US3709598A

US3709598A - Optical system for capsule inspection

Info

Publication number: US3709598A
Application number: US00183199A
Authority: US
Inventors: W Vandenberg; H Chae; E Stewart; W Palmer; H Padgitt
Original assignee: Eli Lilly and Co
Current assignee: Eli Lilly and Co
Priority date: 1971-09-23
Filing date: 1971-09-23
Publication date: 1973-01-09
Anticipated expiration: 1990-01-09
Also published as: BE788990A; CH571213A5; IE36903B1; ATA817072A; BR7206597D0; YU240072A; HU167593B; CA998453A; IL40314A; AU4683072A; ES406940A1; DE2246088A1; AT351298B; DK144000B; SE390668B; IE36903L; DD100078A5; IT965472B; DK144000C; NL175343B

Abstract

Medicinal-capsule inspection apparatus. Successive capsules spun on their axis in an inspection position are illuminated by intense light originating at a single lamp filament and reflected onto the capsule from a mirror in the form of a narrow band cut from an ellipsoid and positioned so that the filament is adjacent to one focus and the capsule adjacent to the other focus. The mirror wraps around the capsule endwise and produces on the capsule, as seen by a side-viewing lens and two end-viewing lenses, a narrow well-defined and continuous glare line area which is unique in that it curves over the ends substantially to the axis. The lenses project images of the capsule in side and end elevation. Masks at the image planes block the glare light from acceptable capsules, but contain apertures in selected relation to the image glare light areas, which pass light specularly reflected from defects in selected observation areas on the spinning capsules. Such light acts on light sensors behind the apertures to generate electrical control signals which provide inspection output information.

Description

Vandenberg et al.

Jan. 9, 1973 154] OPTICAL SYSTEM FOR CAPSULE INSPECTION [75] Inventors: Willard J. Vandenberg; H1 Chul Chae, both of Indianapolis; Elmer R. Stewart, Camby; Wayne R. Palmer, Mooresville, all of Ind.; Howard R. Padgitt, Park Ridge, 111.

[73] Assignee: Eli Lilly and Company, Indianapolis,

Ind.

[22] Filed: Sept. 23, 1971 [21] App1.No 183,199

[52] US. Cl.. ..356/l98, 209/111.7, 250/224, 350/293, 356/209, 356/237 [5 I] Int. Cl. ..G01n 21/22, G01n 21/48 [58] Field of Search ..209/111.5,111.6,111.7; 250/224; 356/198, 209, 237; 350/293 56] References Cited UNITED STATES PATENTS 3,123,217 3/1964 McMillan et al. ..209/1 1 1.5

Primary Examiner-Ronald L. Wibert Assistant Examiner-F. L. Evans Attorney-Verne A. Trask et al.

[57] ABSTRACT Medicinal-capsule inspection apparatus. Successive capsules spun on their axis in an inspection position are illuminated by intense light originating at a single lamp filament and reflected onto the capsule from a mirror in the form of a narrow band cut from an ellipsoid and positioned so that the filament is adjacent to one focus and the capsule adjacent to the other focus. The mirror wraps around the capsule endwise and produces on the capsule, as seen by a side-viewing lens and two end-viewing lenses, a narrow welldefined and continuous glare line area which is unique in that it curves over the ends substantially to the axis. The lenses project images of the capsule in side and end elevation. Masks at the image planes block the glare light from acceptable capsules, but contain apertures in selected relation to the image glare light areas, which pass light specularly reflected from defects in selected observation areas on the spinning capsules. Such light acts on light sensors behind the apertures to generate electrical control signals which provide inspection output information.

51 Claims, 20 Drawing Figures PATENTED JAN 9 I975 SHEEI 1 BF 6 PAIENTEflJAu Basra 3.709.598

sum s or 6 PATENTEDJAN 9191a SHEEI 8 [1F 6 OPTICAL SYSTEM FOR CAPSULE INSPECTION CROSS REFERENCES The optical system of this application is especially useful in the inspection apparatus disclosed in the copending application of William D. Wagers, Jr., et al., Ser. No. 105,262, filed Jan. ll, I971. The ellipsoidal mirror lighting system disclosed is claimed in a copending application of Howard R. Padgitt, Ser. No. 223,199 filed Feb. 3, 1972. The output signals may be processed as disclosed in copending application of Hi Chul Chae et al., application Ser. No. 183,948 filed Sept. 27, l 97 l BACKGROUND OF THE INVENTION This invention relates to an optical system for rapidly inspecting large numbers of medicinal capsules positioned successively in an inspection position where each capsule is spun on its axis to expose its entire surface for inspection.

Medicinal capsules are made in large numbers on complex and sensitive machines, from gelatin or other material. Gelatin capsules consist of caps and bodies which are formed by dipping pins in a gelatin solution, causing the coatings on the pins to set, stripping the set coatings, cutting them to length, and telescopically assembling the empty caps and bodies with sufficient tightness to stay together during handling as empty capsules but sufficiently loose to permit disassembly for filling. The empty capsules must be as free as possible of imperfections, not only as a matter of product quality, but especially to provide proper operation of the machines in which they are filled, to avoid waste and improper dosage of the medicinal material, and to avoid production of imperfect filled capsules.

The requisite capsule quality requires I percent inspection of empty capsules before their use or sale to others for use. Heretofore, this has been done by visual observation by inspectors as the capsules are conveyed in a single-thickness layer across an illuminated screen. Such visual inspection is expensive, and not fully effectrve.

Representative capsules consist of caps and bodies each having a deep cupshape with a generally cylindrical side wall and a rounded end. The telescopically assembled capsule may vary considerably in length. The skirt of its cap is commonly formed with an outward flare or taper. The external surfaces may be out of round either because of variation in wall thickness or because of distortion. Several other permissible variations may occur in acceptable capsules. Thus, even good capsules present a somewhat irregular shape which renders inspection a difficult problem.

Effective inspection is also made difficult by the large number and variety of defects which can occur. Defects which should be found on inspection include split or cracked capsules, capsules with holes or notches in their wall, mashed or flattened capsules, telescopically deformed capsules, cuttings encircling or otherwise attached to the capsules, incomplete capsules, crimps, turned edges on the caps, black specks, dents, bubbles, depressed ends, ragged edges on the cap, scrapes, pin marks, thin spots, etc. These different defects respond differently to optical inspection, and some require different inspection conditions than others. Also, inspection apparatus should be able to detect defects in colorless and transparent capsules as well as in capsules of various colors and degrees of translucency and in two-color capsules, that is with caps and bodies of different colors. inspection should also apply to capsules of different shapes, including those with hemispherical ends and those of parabolic shape.

It has been found especially difficult to inspect for defects in the rounded shoulder areas at the ends of the capsules, between the generally straight edges and the rounded ends, and especially in the parabolic surfaces of capsules having parabolic body ends.

Inspection must also take account of deviations built into the capsules for special purposes. In some capsules, a pair of diametrically opposite internal bosses are formed in the cap to bind the caps and bodies of empty capsules against separation. Also, some capsules have a plurality of circumferentially-spaced internal lands in the caps to retain together the caps and bodies of assembled filled capsules, such as disclosed in Hostetler et al., US. Pat. No. 3,173,840 of Mar. 16, 1965, entitled Separation-Resistant Capsules. Such internal bosses and lands produce external surface deviations similar to some defects.

Automatic or machine inspection has not previously been accomplished. ln a previous study for the assignee of this application, some 10 years ago, Stanford Research institute the final report of Stanford Research Institute is of record in the cited copending application of Wagers et al., Ser. No. 105,262 proposed an inspec tion system in which capsules were rotated rapidly in front of a moving set of small photosensitive scanning apertures, and built a hand-fed laboratory scanning machine for studying this proposal. While the optical system of that study appeared promising, no means was available to handle and present capsules for the inspection at a sufficiently high rate, and when such a means had been developed as disclosed in the aforesaid copending application of William D. Wagers, J r., et al., it was then found that the proposed optical system was inadequate, and much development work has been necessary to produce the present operatively-useful system.

The present invention provides an effective optical system for inspecting capsules presented in succession in a uniform position and orientation and rapidly spun on their axis to present their entire surface for such optical inspection. it provides for inspecting not only the generally cylindrical side surfaces of capsules, but also the rounded ends and the shoulder portions between the sides and ends, so that a complete inspection may be accomplished in a single inspection cycle at the same inspection station.

The invention is applicable to transparent or colorless capsules as well as to capsules of uniform color and to two-color capsules. [t is also applicable to capsules having normal surface deviations resulting from internal bosses and lands, and to capsules of different sizes and shapes, including both those with generally spherical ends, and those in which the body end has a parabolic or bullet shaped configuration.

It is convenient to discuss inspection lighting and viewing with reference to specular reflection or glare lines on the surfaces of good capsules; yet it is to be remembered that the inspection is not so much to observe conditions on good capsules but rather to see defects for which the capsules should be rejected. In inspection of true surfaces of revolution such as those of bearing rollers, it has been proposed, as in Stevens US. Pat. No. 2,944,667, to observe light which was specularly reflected from glare lines, and to sense light decreases in such observed specular reflection. This is not effective for capsule inspection, in part because permissible irregularities of capsule shape make the glare unstable, and also because of the variety and obscurity of the defects which must be found.

SUMMARY OF THE INVENTION In accordance with the invention, each successive capsule is rapidly spun on its axis at a predetermined inspection position in a groove between a pair of spinning drive rolls while held in the groove by air flow to a suction passage at the bottom of the groove. Such rotation in itself performs an inspection function, in that excessively deformed or incomplete capsules are thrown off the rolls and effectively rejected. Each capsule, during its rotation on its axis in the inspection position undergoes optical inspection both of its side area and of its end and shoulder areas. Preferably, the side and end inspections are performed simultaneously, and use a common lighting system, but it is contemplated that side and end inspection could be done separately or with separate lighting means.

The capsule presents a convex reflective surface which forms part of the optical system, and the lighting system produces specular reflection from that surface into the viewing lens systems over glare line areas which can vary in shape and definition depending both on the shape of the capsule and on the shape of the light beam with which it is illuminated.

in general, a preferred inspection apparatus includes (1) viewing apparatus which may comprise a side-inspection lens system and two end inspection lens systems; (2) a lighting system which casts light onto the capsule from a series of points in an elongated narrow area which wraps around" the capsule lengthwise and, as seen by the lens systems, produces specular reflection over a glare line which is substantially continuous from end to end along the capsule and over its rounded ends; (3) image planes to which the lens system project images of the side and ends of the capsule, and (4) light sensors which sense light in such images over linear areas spaced from the glare lines therein. The inspection cycle for each spinning capsule is continued through a plurality of capsule revolutions, for example five revolutions, to provide redundancy in the inspection.

The side-inspection lens system sees the glare line over the entire length of the generally cylindrical side surface and may to some extent see the glare line on the adjoining shoulder surfaces of the capsule. Side inspection preferably utilizes a series of light sensors responsive to light in different portions of a substantially continuous linear area parallel with and spaced from the glare line the side image of the capsule, and one or more of these sensors may sense built-in deviations as from separation-resisting internal lands and bosses in the capsule wall.

inspection of end and shoulder areas of the capsule is greatly facilitated by the "wrap-around" lighting system, which produces an elongated glare line over substantially the whole lengthwise curved surface of the capsule end, as seen by a single lens system located beyond the capsule end. Without such warp-around lighting only a small spot of glare appears. The wraparound lighting and linear glare line permits the viewing system to see defects in all parts of the difficult end and shoulder areas.

With an end-viewing lens system which sees the capsule end-on, the elongated glare line appears as a radial line on the image of the capsule end. The end inspection may utilize only a single light sensor arranged to sense light in radial linear areas of the end-image, spaced angularly from the radial position of the glare line.

With the side and end sensors arranged to sense light in image areas spaced from the glare areas, they are responsive to both decreases and increases in light. They will thus see decreases in difi'use light from their inspection areas such as may be caused by black spots, holes, cuts, and the like in such inspection areas. Also, and especially, they will see increases in light caused by specular reflection into the sensors from defects such as bubbles, crirnps, and the like which produce abrupt changes in the curvature of the capsule surface.

The sensors are connected to electrical circuits in which they produce signals which contain variations or spikes corresponding to light variations representing the observed capsule defects. These signals are processed and analyzed, as to control the operation of accept-reject mechanism to accept or reject the inspected capsules and to count both the accepted and rejected capsules.

In signals from light sensors arranged to observe defects in areas of the capsule which contain no built-in deviations, the occurrence of a single spike of prede termined size on each revolution of the capsule may be taken as sufiicient to cause rejection of the capsule. Where the light sensor is one which sees built-in deviations the signal processing and analysis must take account of the appearance in the signal of the variations corresponding to such built-in deviations. A preferred method of processing signals containing such built-in spikes is to measure the time interval between spikes so that the presence of a defect-caused spike will produce a time measurement between successive spikes which is shorter than the predetermined normal time between spikes from built-in deviations. A reject signal can then be derived from the abnormal short time measurement.

The substantially continuous end-to-end glare line on the capsule is produced by specular reflection of light rays suitably directed onto the surface of the spinning capsule from a plurality of points over an elongated narrow light source area.

The narrowness is desirable to delineate a narrow glare line area on the capsule and in its image, so that a predetermined and uniform relationship is obtained between the glare line area and the light sensing area. The elongation of the light source area is desirable to produce uniform end-to-end illumination of the capsule. The light source area should extend over a wide angle in the capsule plane so that the light rays converge on to the capsule over that wide angle to produce a substantially continuous end-to-end glare line.

Operative illumination may be obtained in various ways. For example, an elongated narrow light source area may be provided by the use of one or more lamps having elongated line filaments, by shaped luminescent tubes, by means of light conducting fiber optics, beamsplitting optical devices, etc. We have found, however, that best results are obtained by the use of a single light source and a shaped mirror in the form of a narrow segment of an ellipsoidal surface, with the mirror disposed in such a way that the light source is adjacent to one focus of the ellipsoidal mirror surface and the capsule is adjacent to the other focus of that ellipsoidal surface, as shown in the aforesaid copending application of Howard R. Padgitt. That illumination system produces a thin wedge-shaped beam of converging light rays directed toward the capsule from over a wide angle and which wraps around the ends of the capsule to produce specular reflection over a narrow glare line which is continuous end-to-end along the surface of the spinning capsule.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate the invention, and show a preferred specific embodiment of the invention. In such drawings:

FIG. 1 is a sectional view showing in side elevation mechanism for supplying capsules in sequence at high feed rates to an indexing inspection head;

FIG. 2 is a plan view, with parts broken away, of the inspection head, with an optical inspection system in accordance with the invention shown diagrammatically;

FIG. 3 is a vertical section on the line 3-3 of FIG. 2;

FIG. 4 is a side elevation, on an enlarged scale, one of the drive rolls of the inspection head, in relation to to a representative capsule;

FIG. 5 is a plan view of optical inspection mechanism embodying the invention, shown in relation to the inspection position on the inspection head;

FIG. 6 is an end elevation of the optical mechanism shown in FIG. 5;

FIG. 7 is a side elevation of the optical mechanism shown in FIGS. 5 and 6;

FIG. 8 is a side elevation, with the cover plate removed, of a preferred illumination system, showing diagrammatically the positions of the light source and capsule in relation to the foci of the ellipsodial mirror;

FIG. 9 is a front elevation of the illumination mechanism shown in FIG. 8, with the front window removed and with parts shown in section;

FIG. 10 is a side elevation of the illuminated capsule as seen from the point of view of the side scanning lens system;

FIG. 11 is an end elevation of the illuminated capsule as seen from the point of view of the top scanning lens system;

FIG. 12 is a side elevation like that of FIGv 11 showing an illuminated capsule of the type having a parabolic end, sometimes referred to as a paracap" capsule;

FIG. 13 is a diagram of the side-inspection optical system, taken substantially as a horizontal section on the line l313 of FIG. 8;

FIGS. 14a and 14b are enlarged portions of the optical system of FIG. 13;

FIG. 15 is a view of the image of a capsule as it appears at the image plane of the side-viewing optical system, showing the relationship of the glare line and the mask openings;

FIG. 16 is a diagrammatic vertical section showing the relationship of the image-plane mask and four photo detector devices used to inspect four areas of the capsule as seen in FIG. 15;

FIG. 17 is a diagram of the end-inspection optical system taken substantially as a vertical section in the plane of FIG. 8;

FIG. 18 is an enlarged portion of the diagram of FIG. 17; and

FIG. 19 is a view showing the image of the capsule end as seen in the image plane of FIG. 17 and showing the relationship of the glare line to a preferred form of mask opening.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A representative capsule 25, as shown in FIGS. 4 and 10, comprises a body 50 having a generally cylindrical or slightly flaring side wall 49 and a hemispherical end 51. A cap 52 is telescopically received over the open end of the body 50 and includes a hemispherical end 53 and a side wall or skirt portion 55 which is generally cylindrical but commonly flares outward toward its open end. The cap is formed with two diametrically opposite internal bosses 54 for gripping the body 50 to resist cap and body separation and these appear as slight depressions in the outer surface of the cap. The cap is also formed with three broad internal lands 56 at the shoulder portion where the end 53 joins the side 55, and these produce three sets of depressions and ribs on the surface of the cap shoulder. The deviations thus occurring on the surface of the capsule, which is otherwise designed as a surface of revolution, are taken into account in processing and analyzing the inspection results.

The capsule handling and feeding mechanism shown in FIG. 1 comprises a hopper 10 for reception of bulk capsules, having a reciprocating agitating bar 12 at its bottom adapted to feed capsules from the hopper 10 to a bottom trough and there to the upper stretch of a chain conveyor 14 trained about a lower sprocket I6 and an upper sprocket or transfer wheel 18. As the conveyor leaves the hopper 10 it passes through a rectifying station comprising a brush 20 and a belt 22 operative in conjunction with the shape of the buckets 15 of the conveyor to reverse the position of body-forward capsules so that all of the capsules in the conveyor are uniformly presented in a cap-forward position. The capsules then pass over the upper sprocket or transfer wheel 18 where internal plungers I9 lift the capsules from the'conveyor buckets and transfer them successively to the indexing inspection head 24.

The inspection head 24, FIGS. 2 and 3, comprises a circumferential series of spaced vertical rollers 26, forming between them a circumferential series of capsule receiving grooves 28. The bottom of each groove is open to a suction passage 30 for communication with control chambers and passages within the head. Suction applied through such passages 30 retains the capsules 25 in the grooves, and release of the suction and/or an air blast discharges the capsules off the head.

The inspection head 24 rotates clockwise as seen in FIG. 2 and carries capsules from a LOAD station at the bottom through three indexing steps to an INSPECT station at the right and then through three additional indexing steps to a REJECT station at the top and an ACCEPT station just beyond the reject station.

The indexing drive to the inspection head 24, is through a central shaft 32 shown in FIG. 3. This drives a hub 34 on which a ball bearing 36 supports a ring gear 38 which is continuously driven by a spinner drive gear 40 and which drives pinion gears 42 fixed on the shafts 43 of the capsule drive rollers 26. This drive train causes the rollers 26 to spin the capsules 25 in the grooves 28 during each indexed stop position of the inspection head. The ring gear 38 is desirably driven continuously in the same direction as the indexing hub 34, which produces the desired spinning rotation of the drive rolls 26 and capsules 25 during indexed stops and temporarily reduces such rotation during indexing movements.

The capsule driving rollers 26 are desirably shaped as shown in FIG. 4, with an upper cylindrical half 44, a lower frusto-conical half 46, and a sharply defined shoulder 48 between the two. The capsule is in capdown position, so that its cylindrical body side wall 49 bears against the cylindrical upper half 44 of the roll 26 and the upper end edge of the cap 52 abuts against the shoulder 48 of the roller 26. The lower conical surface 46 of the roll 26 stands clear of the flared side wall 55 of the capsule cap 52 but engages the capsule cap 52in a substantially circular portion between the

indentations

54 and 56. Each pair of rollers 26 thus supports a capsule 25 for substantially stable rotation on its axis, and drive the capsule in that rotation.

For applying suction or air flow control of the capsules, the upper portion of the inspection head 24 is formed of a ring 58 defining a cylindrical cavity in which is seated a valve block 60 held in fixed position within the ring 58 by a manifold 62. As seen in FIG. 2, the valve block 60 has a main suction chamber 64 which applies suction to the suction passages 30 throughout the travel of the capsule grooves 28 from the loading station to, but short of, the reject station. Opposite the REJECT station, the valve block has a suction chamber 66 which is normally connected to a suction supply line 63 through a valve 65 but which is switched to an air pressure supply 67 through a valve 69 when the capsule in that position is to be rejected, so that instead of the capsule being held in the groove 28 by suction, it will be ejected by an air blast through the passage 30. The

valves

65 and 69 can be shifted simultaneously by solenoids. Opposite the ACCEPT station, the valve block 60 has an air pressure port 68 which is continuously connected to the air pressure supply 67 to feed air under pressure to the passage 30 at this index position and thereby eject from the inspection head all capsules which are not ejected at the reject position. With this arrangement, control of the

valves

65 and 69 determines whether suction or air is applied to the control chamber 66 and this determines whether each capsule which reaches the reject station will be rejected or retained for discharge at the accept station. Such control may be effected in response to the inspection output signal from the inspection which occurs at the inspection station.

The inspection which occurs at the INSPECT station is indicated diagrammatically in FIG. 2 and is more fully described below. The capsule at this position is illuminated from a high intensity lamp 70 by way of a mirror 72 in the form of a narrow band cut from an ellipsoidal surface. As shown in FIG. 8, the mirror band extends in the plane 74 of the capsule axis through an arc of approximately 160 about the center of the capsule so that it extends substantially to the capsule axis itself. This projects onto the capsule a circumferentially-narrow, longitudinally-wide beam or wedge of light rays which approach the capsule from points distributed over a wide angle in the plane of its axis. This produces specular reflection into the lens of the side-viewing lens system on the axis 78, and causes that specular reflection to occur from a narrow and welldefined glare area along the entire side of the capsule. The side-viewing lens 80 projects an image of the capsule at an image plane 82. Here, the light from the glare line is blocked by a mask 84 containing an aperture 86 close beside the image of the glare line. Light sensing means, shown as a photo detector device 88, is positioned behind the aperture, and this is preferably set to respond both to decreases in the observed light and especially also to light increases caused by specularly reflected rays directed through the aperture by capsule defects.

The optical mechanism is more fully shown in FIGS. 5, 6, and 7. It comprises a mounting table 90 adjustably carrying a base 92 having fixed thereto a lens supporting column 94 in which are adjustably mounted an upper lens tube 96 for viewing the top of the capsule, a lower lens tube 98 for viewing the bottom of the capsule and a middle lens tube 100 for viewing the side of the capsule. The column 94 also supports a mirror mount 102 carrying a mirror 104 in position to fold light rays from the top of the capsule 25 to a horizontal position into the lens tube 96. Similarly, the column 94 supports a mirror mounting 106 having a mirror 108 for folding the light rays from the bottom of the capsule to a horizontal direction into the lower lens tub 98.

The lens tubes carry viewing lens assemblies 109, 1 l0, and 1 1 1 and at the rear carry adjustment supports 112 for supporting mask carriers 116 at the image planes of the lens assemblies. Each adjustment support 112 comprises a guide way 114 adapted to receive a mask carrier 116 slidable laterally in the guide way 114. The upper and lower carriers 116 are adjusted in their support by adjustment screws 118 mounted in side plates 120. For convenience in resetting the sideviewing optical system to a predetermined adjustment, the mask carrier 116 (not shown) on the middle lens tube 100 is engaged at one side by an adjustable spring plunger 119 and at the opposite side by a micrometer adjustment screw 122.

Each lens tube is adjustable axially of itself, to focus on the capsule, by an adjustment screw 124 which rotates in a fixed position in the column 94 and drives a runner 126 fixed to the lens tube.

Each mask carrier 116 comprises a body and a cover plate 117. The body forms a seat for removably mounting a rectangular mask in the image plane of the lens system, and provides for mounting one or more photo detector devices immediately behind the mask in position to react to light passing through the aperture areas of the mask. Preferably, single photo detectors are used in the top and bottom carriers for inspecting the capsule-ends, and a plurality of photo detectors are used in the carrier on the middle lens tube 100, for inspectin g different longitudinal areas of the capsule side. The carrier 116 may also contain electronic components used with the photo detector, used as a preamplifier.

For aligning and focusing the system and the mask, the cover plate 117 of a mask carrier 116 may be removed and replaced with a frame 129 holding a ground-glass image screen at the image plane, either with or without the mask being present. In FIG. 6, the capsule-side lens tube 100 is shown as provided with such a frame 129 and an image screen 128. An image 25' of the capsule 25 and its glare line is shown on that screen 128.

In the arrangement shown in FIGS. -7, the optical systems for viewing the side and the ends of the capsule have their centerlines in the same plane, and such plane passes through or lies closely parallel to the vertical axis on which the capsule 25 is rotated at the inspection position on the inspection head 24. However, the side and end viewing systems may be in different planes.

The illumination system shown in FIGS. 5-9 comprises a mounting block 130 mounted on the base 92 and supporting a mounting post 132 on which a clamp 134 supports a mirror block 136. The outer side wall of the mirror block 136 carries a lamp housing 138 in which the lamp 70 is mounted in a pre-focusing base.

As shown in FIGS. 8-9, the mirror block 136 is machined and polished to form the mirror surface 72 in the form of a narrow strip or band extending through a very wide angle in the plane of the capsule axis. The mirror shown extends over an angle of approximately I60". The mirror should be shaped to reflect light from the lamp 70 onto the capsule over the whole end-toend surface of the capsule and to direct the light in rays which converge toward the capsule in the plane of the capsule so that the capsule receives light from a multiplicity of points in a narrow elongated area extending over a wide arc about the capsule. Desirably the mirror surface is also shaped with a transversely concave surface to concentrate light from its entire width onto the capsule. Further, for uniformity of illumination the length of the light paths from the lamp 70 to the mirror and thence to the capsule should be approximately uniform in all parts of the system.

One geometric surface which satisfies these requirements to a high degree is an ellipsoidal surface. The mirror surface 72 shown is thus a narrow band of the surface of an ellipsoid having its two foci F-] and F2 substantially in the positions shown in FIGS. 8 and 13. The central plane 74 of the mirror section is not on the axis of revolution RR of the ellipsoid, but is at an angle thereto as shown in FIG. 13. The two foci F-! and F-2 are, of course, on the axis of revolution R-R. The characteristic of the ellipsoidal mirror surface 72 is such that light emanating from the focus F-l is reflected from any and all points of the mirror surface 72 to the opposite focus F-2. The lamp 70 has a coil filament 142 which is desirably located substantially on the axis of revolution R-R, close to the focus F-l, and the mirror block 136 is so mounted that the capsule 25 lies close to the secondary focus F-2. Preferably, and as shown, both the lamp filament I42 and the capsule 25 are slightly defocused and located to the right of the foci. This arrangement places the capsule in the light rays converging toward the focus F-2. From the point of view of the capsule, each point on the surface of the narrow band of ellipsoidal mirror takes on substantially the full brightness of the filament 142. From the point of view of the capsule, the mirror is the source of light and that source is in the form of an elongated narrow area from all points of which rays of light are directed toward and converge onto the capsule 25. The area source of light is narrow circumferentially of the capsule, but extends in a wide angle of nearly 180 in the plane of the capsule 25.

Direct illumination from the lamp to the capsule is desirably avoided. The front of the mirror block 136, to the left in FIGS. 8 and 13 is closed by a window 146 which desirably has a concave shape as shown in FIG. 8. Such window 146 is fully open to pass all light from the mirror surface 72 to the capsule 25, but its front face is blackened over an edge portion to form a mask 148 to block direct illumination of the capsule from the lamp 70.

The capsule surface is itself a smooth convex reflective surface, at least approximating a surface of revolution. Light from the mirror 72 will be specularly reflected by that capsule surface into the sideand endviewing lenses from a lengthwise glare area on the capsule surface and will appear as an intense glare line. The narrow uniform width of the mirror will aid in causing the glare line to be uniform in width and sharply defined at its edges. The elongated arcuate shape of the mirror will cause the glare line to be substantially continuous from end to end along the surface of the capsule and to wrap around the curved shoulder and end portions; and this is of special importance for inspecting those portions.

FIG. 10 shows a capsule 25 as seen from the point of view of the side-scanning lens 110, when illuminated by the illumination system of FIGS. 8-9. This illumination produces on the capsule 25 a well defined narrow glare line 150 which extends axially along the surface of both the body 50 and the cap 52, with the portion on the cap 52 slightly offset from that on the body 50 because of the larger diameter of the cap 52. While a glare line on a cylindrical surface would normally be relatively narrow, the glare line 150 on the capsule is well defined and especially narrow by reason of the narrowness of the mirror 72 from which it is illuminated. In effect, the narrow glare line is an image on the convex reflective surface of the capsule of the narrow surface of the elliptical mirror 72.

The ends 152 of the glare line 150 extend beyond the

cylindrical portions

49 and 55 of the capsule 25 and up into the

hemispherical end portions

51 and 53 of the body and cap. This is the result of the wrap around characteristics of the ellipsoidal mirror 72, in that that mirror extends in a wide angle of approximately l60 about the center of the capsule in the plane of the capsule. As shown in FIG. 8, a bundle of rays 0 from the filament 142 which strikes the mirror 72 at a point close to its centerline Y will be reflected as reflected rays a'onto the side of the capsule 25, and this will produce specular reflection horizontally into the entrance pupil of the side-viewing lens 110. Also, a bundle of rays 1) from the filament 142 which is reflected from a point on the mirror spaced upward from the horizontal axis Y will be reflected as a bundle of rays b which will strike the upper end of the capsule from an upward inclination, and such rays will cause specular reflection from the hemispherical end surface of the capsule in a generally horizontal direction into the same entrance pupil of the side-viewing lens 110. It is thus because of this wrap around light source arrangement that the glare line 150 on the capsule shown in P10. is caused to extend the full length of the cylindrical side surface and there-beyond into the hemispherical end surface. That same wrap around feature produces an elongated glare line on the end of the capsule as seen by the end-viewing lens 109 or 111, as shown in FIG. 11, and this will be discussed in more detail later.

Inspection of the side area of the capsule is carried out as shown diagrammatically in FlGS. 13 and 14a, b. As has been described, the filament 142 of the lamp 70 supplies light to the narrow band of ellipsoidal mirror 72, and from the point of view of the capsule 25 high intensity light is reflected from the full width of that band of mirror surface 72 in converging rays 156 toward the capsule 25. The side-viewing lens 110 projects an image 125 of the capsule 25 on the face of the mask 160. A thin wedge-shaped pencil of converging rays 156 are specularly reflected from the glare line area 150 on the capsule, as diverging rays 156', into the entrance pupil of the side-viewing lens 110, and such lens produces an image of the glare line area at an area 150' in the image plane on the face of the mask 160. The lens 110 shown diagrammatically in FIG. 13 is in practice a lens system, preferably one of high quality specifically designed for l:l magnification in this application. The plane in which it is focused can have a significant bearing on the results. For example, because of the divergence of the light rays 156' reflected from the convex specularly-reflecting surface area 150 of the capsule, the glare appears to come from a line source 151 inside the capsule where the divergent rays 156' intersect. The lens 110 should not be focused on that glare line source 151 but instead should be focused on the glare surface 150 of the capsule.

At the image plane, all the light rays 156' from the glare line area 150 which enter the lens 110 are directed to the glare line image area 150' on the mask, and since this portion of the mask is opaque, all such glare light is blocked. Close beside the glare line the mask contains an aperture 162, behind which a series of photo detectors l65a-d are located to sense light transmitted through the aperture 162. Specularly reflected light from the vicinity of the observed face of the spinning capsule normally does not enter the lens 110 and reach the mask aperture 162, provided the capsule has no defects. However, when a surface irregularity such as a bubble 164 rotates through the vicinity of the glare line area 150, as shown in FIG. 14, a different condition will exist. The surface irregularity or bulge at the bubble 164 may cause some variation in the specular reflection of light from the glare line area 150, but any such variation at the glare-line image 150' on the mask 160 has no effect in the inspection process, since all light striking the mask at that area is blocked. However, as the bubble 164 approaches the glare line area 150 its surface irregularity or bulge will pass through a viewing area 163 adjacent the glare area 150 and will cause rays of light such as the ray 166 to be specularly reflected as a reflected ray 166' directly into the aperture 162 in the mask 160. This produces a large increase in the light entering the aperture 162 and sensed by the photo detector 165, which causes a large variation or spike in the electrical output signal from the inspection sensing device.

The arrangement just described has been found effective to sense capsule imperfections such as bubbles, crimps, turned edges, telescopically mashed capsules, and the like which cause variations from the circular configuration of the capsule surface and hence cause specular reflection of the intense light into the aperture 162. The photo detectors at that aperture can also sense decreases in diffused light, such as is caused by splits, black spots, holes or cuts occurring in manufacture etc. However, it is preferable not to rely wholly on observation of such light-decreases by the detectors 165 which may be set to operate at high light intensity levels. For more reliable detection of such other imperfections, and especially splits and cracks at the edge of the capsule cap 52, the mask 160 is provided with a second aperture 168 and detector 170 responsive to light from a viewing area 172 positioned outside the glare area 150, conveniently for example, on the opposite side of the capsule-lens center line from the glare line area 150. A cut or split passing through that area 172 will cause a variation in the diffusely reflected light reaching the aperture 168, and this will activate the photo detector 170 located behind that aperture. As shown in FIG. 14, a light ray 169 strikes a cut 171 as it passes through the area 172 and this will produce variation in the light ray 169' which enters the aperture 168. The detector 170 is desirably set to respond to light decreases.

It will be seen that the cut-line observation area is substantially in the same transverse plane as the glare area 150. This permits both to be in focus for the lens 110. To obtain this result, in the arrangement shown, the angle between the mirror plane 74 and the lens axis is desirably about 50.

FIG. 15 shows an enlarged image of a capsule as such image appears at the image plane at the face of the mask 162. The capsule is in inverted position by reason of the inversion caused by the lens 110. The glare line image appears as a shaded line with its upper capsection displaced to the right of the lower body section. A bulbous enlargement 164 of the glare line image represents the image of the bubble 164. The apertures of the mask are super imposed on the capsule image. The principal aperture 162 is shown as an open linear area of narrow width having an upper section offset to the right of the lower section so that both sections lie close to and parallel with the glare line image 150'. The bulbous image 164' of the bubble 164 is shown to cross the lower section of the aperture 162 and represents the passage of light through such aperture to activate a photo detector 165. FIG. 15 also shows the image 171' of the edge split 171 on the cap of the capsule, and shows the aperture 168 in a position to receive light as the image 171' of the split passes the aperture 168.

The capsule is of the type in which the cap contains a pair of internal bosses 54 for producing separation resistance of empty capsules, and a series of internal lands 56 for producing separation resistance in filled capsules. These appear at different levels on the image 125 of the capsule as shown in FIG. 15 so that they may be detected by separate photo detectors placed at corresponding levels.

For detecting defects in the side-scanning system described, a plurality of detectors 165 a-d are used behind the aperture 162, as shown in FIG. 16. Here, an upper detector 165a is disposed at a level to observe light reflected through the aperture 162 by the indentations or lands 56 and by defects in their vicinity, a second photo detector l65b for detecting light variations produced by the indentations 54 and by defects in their vicinity, a detector l65c for detecting defects over the upper portion of the capsule body image, and a detector 165d for detecting defects in the lower part of the body image. The latter is longer than the others to take account of normal variations in capsule length. A greater or lesser number of detectors might be used, but we have found four to give good results. Any of various types of photo detector devices might be used, but we have found it convenient to use edge-contact silicon photovoltaic cells.

The capsule-end illumination and scanning system is shown diagrammatically in FIGS. 17 and 18. As explained in connection with FIGS. 8-9, the filament 142 lying substantially at the principal focus R1 of the ellipsoidal mirror surface 72 directs rays of light to all points on that surface 72 and such rays are reflected toward the capsule 25 located substantially at the secondary focus F-2 of the ellipsoidal surface. That narrow, elongated ellipsoidal surface directs light toward the capsule 25 over a wide angle in the plane of the capsule so that the mirror light source is in eflect wrapped around the ends of the capsule. Thus, in FIG. 8, the bundle of rays c are reflected from near the lower end of the mirror 72 and thence upward as rays c toward the lower end of the capsule 25. This wrap around is especially important in the end-scanning operation, since it produces a glare line area observable by the end scanning lens 1 11 which is of uniquely long length on the curved end surface of the capsule. Illumination of that spherical surface from a spot light source, such as the filament 142 of the lamp 70, would produce only a small spot of specularly reflected light as that end surface is seen by the viewing lens system, and such illumination provides only limited inspection of the end surface and fails to reveal all the defects. In contrast to this, the illumination system here shown produces a long linear area of specular reflection and greatly increases the effectiveness of the end inspec- IlOI'l.

In the optical diagram of FIG. 17, a light ray d from the filament I42 is reflected from the mirror surface 72 at a at a point 173 well below its centerline y, and is reflected as a ray d toward the capsule 25 and strikes the spherical end surface of the capsule at a point D on its shoulder only a short distance above its line of juncture with the cylindrical side surface of the capsule. The capsule surface reflects the ray as a ray d" into the entrance pupil of the end-viewing lens 111 of the top end-scanning optical system. Another ray of light e from the filament 142 is reflected from the mirror surface 72 at a point 174 far above the centerline y of the mirror and is reflected toward the capsule as a ray e which strikes such capsule at a point E only a short distance from the axis of the capsule. The capsule sur face specularly reflects the ray e" into the entrance pupil of the relay lens 111. The points D and E of incidence of the rays d and e' and of reflection of the rays d" and e" are shown on the large scale FIG. 18 and it is seen that they lie far apart on the arcuate surface of the end of the capsule. The entire linear area 176 between the points D and E will of course be illuminated by light rays reflected from points on the mirror surface 72 between the

points

173 and 174 at which the rays d and e are reflected. Such illumination will be specularly reflected from the entire linear area between the points D and E on the capsule end surface into the lens 111. A glare line is thereby produced on the spherical end of the capsule which extends substantially from the line of juncture of the end and side surfaces up to the axis of the capsule. The width of that glare line will be limited in part by the circumferential curvature of the end surface, but will also be limited by the narrowness of the mirror 72 from which the light rays are directed onto the capsule.

By this means, the wrap-around light source formed by the mirror 72 produces an elongated linear glare line area on the spherical or similarly curved end surface of the capsule as seen by the end-on viewing lens 111. Such lens 111 projects an image of the capsule end on the face of a mask 178. In that image 225, shown enlarged in FIG. 19, the glare line area appears as a radial linear area 176'. The mask 178 is arranged to block the glare light in the glare line area 176' and is provided with one or more apertures to pass light specularly reflected from the end of the capsule by defects therein. A preferred form of mask aperture 180 is superimposed on the image 225 of the capsule in FIG. 18, and consists of a generally Y-shaped opening in the mask, so positioned that the radial glare line area 176' lies between the radial arms of the Y and generally opposite from the leg of the Y. Y

A single photo detector 182 is positioned behind a mask 178 to detect variations in the light seen through the aperture 180. The detector may be made to sense both light increases and decreases, but we have found it effective to make the detector responsive to light increases. Large light increases at the aperture 180 will be caused by specular reflection from surface irregularities in a manner analogous to those caused by the bubble 164 in the side inspection, as explained in connection with FIGS. 13 and 14.

It is found that the arrangement described is effective to detect substantially all capsule end defects, including not only eccentric surface deformities but also concentric dimples in the end of the capsule.

The wrap around lighting system also produces good inspection results on capsules 200 having parabolic end portions 202 as shown in FIG. 12. As such capsules are seen by the side-viewing lens 110, the ellipsoidal mirror produces a glare line area 204 which extends along the cap 206 in the same manner as on the capsule in FIG. 10, and extends along the parabolic end portion of the body 208 in a continuous curved line leading well into the shoulder and rounded end of the body. In end-on view, as seen by the end-viewing lens 111, the capsules 200 present an appearance similar to that of the spherical-end capsules as shown in FIG. 11, except that the radial glare line area may be foreshortened at its outer end.

The same apparatus shown may be used to inspect parabolic capsules 200. If desired, however, the sideviewing mask 160 may be replaced by one having a principal aperture shaped to extend parallel with the curved glare line area 250 in the image of the capsule on the face of the mask.

OPERATlON Operation is as follows: Bulk capsules from the hopper are transferred in uniform cap-down position from the buckets of the conveyor to the inspection head 24 at the LOAD station of that head. The capsules 25 are carried in the grooves 28 between the rolls 26 of the head to the INSPECT station at the left of FIG. 2. Here, each capsule is spun on its axis in a fixed position, located horizontally by the positions of the supporting rollers 26 and vertically by engagement of the end of the cap 56 against the shoulder 48 of such rollers. It is held in such position by air flow into the suction passage to the suction chamber 64.

While spinning on its axis in this fixed inspection position, the capsule 25 is illuminated by the lighting system shown in FIGS. 5-9, 13 and 17. All points on the elongated narrow band of ellipsoidal mirror surface 72 reflect high intensity light from the filament 142 adjacent the principal focus F-] of the ellipsoid and direct that light toward the capsule adjacent the secondary focus F-2 of the ellipsoid. From the point of view of the capsule, each point on the surface of the mirror takes on the brightness of the filament and the capsule sees the mirror as the source of light, in the form of an elongated narrow band in and adjacent the plane of the capsule and extending in that plane through a wide arc of approximately l, including on each side of a centerline perpendicular to the axis of the capsule. This directs high intensity light onto the capsule in the form of a thin but wide wedge of light rays which converge toward the capsule over a wide end-to-end angle. As the result, the side-scanning lens I10 sees on the capsule a glare line of specularly reflected light which extends the full length of the cylindrical side surfaces of the capsule body 50 and cap 52 and has end portions which curve into the spherical or otherwise curved closed ends of the body and cap, as shown in FIGS. 10 and 12. The lens 110 produces an image of the illu minated capsule on the surface of the mask at the image plane, as shown in FIG. 15. The mask blocks specularly reflected light in the image of the glare line area I50 but has a narrow aperture 162 closely beside that glare line image which passes light specularly reflected through that aperture from defects such as the bubble 164 (FIG. 14) and such light is sensed by one of the photo detectors 16$ positioned behind the aperture 162.

The glare line area 150 is sharply-defined by reason of the narrow uniform width of the ellipsoidal mirror 72 from which it is illuminated.

On each end surface of the capsule, the thin, wideangle wedge of converging light rays from the ellipsoidal mirror 72 produces a long glare line area 176 which extends from a point close to the base of the end curve to a point close to the axis of the capsule. Specular reflection from that glare line enters the end-viewing lens 111 (or 109) and appears as a generally radial bar 176' on the image 225 of the capsule end (FIG. 19). The light from that glare line is blocked by the mask 178, but light specularly reflected from surface imperfections in the vicinity of the glare line passes through the Y-shaped aperture 180 to be sensed by the photo detector 182. The optical system shown in FIGS. 18 and 19 for the top end of the capsule is duplicated in a similar system containing the lens 109 for the bottom end of the capsule.

The

light detectors

165, 170, and 182 are connected to control electrical circuits having output signals, and so arranged that variations in light reaching the detectots produces variations or spikes in the electrical signals. Such signals are processed and analyzed to control the acceptance or rejection of the capsules and to provide other information as desired. A suitable processing apparatus is disclosed in the aforesaid Chae et al. application.

The optical system for inspection capsules exemplified by the preferred embodiment shown combines illumination and viewing features to produce effective inspection at high rates of a wide variety of defects in medicinal capsules, and is effective both with transparent colorless capsules and with capsules of various colors and of mixed colors. The illumination is characterized by the use of means to direct light onto the capsule in a beam of converging light rays which is thin circumferentially of the capsule but very wide in a plane containing the axis of the capsule, extending in that plane over a wide angle of approximately 80 in each direction from a radial centerline of the capsule so that the illumination wraps around" the capsule endwise. Such thin, wide-angled beam of light rays produces, from the point of view of the side-scanning lens, a welldefined narrow glare line on the side of the capsule which extends the full length of the cylindrical side walls and into the curved ends of the capsule. It also produces on the ends of the capsule a long glare line which extends over a wide arc of the lengthwise curvature of the capsule end, as distinguished from the glare spot produced by a conventional light source which does not wrap around the capsule through the wide angle provided by the present illumination system.

The masks of the optical viewing systems block the light from such glare line areas, and such light is not used in the inspection. However, the production of the continuous, elongated, and well defined glare line areas characterize the illumination which, in the inspection, produces reflections from defects which reveal the presence of those defects with a degree of certainty and reliability not previously available.

In the illustrated embodiment, a single ellipsoidal mirror 72 and illumination system is used to illuminate both the side and the ends of the capsule and this is preferred. It is not essential, however, that the ends be illuminated by the same lighting mechanism as the side, nor that the end-lighting be in the same plane as the side-lighting, since with end-on viewing the plane of the end lighting may be freely rotated about the axis of the capsule, whereas the plane of side lighting must be closely coordinated with the plane of the side-viewing system.

While we consider the single lighting system as shown to be highly advantageous and efficient, it will be possible to obtain similar useful results with other lighting systems which provide illumination in a similar configuration and in which the light planes for the ends may be different from the light plane of the side illumination. For example, instead of using a single compact filament 142 and a narrow elongated mirror surface 72, useful results may be obtained by using an elongated light source such as a long-filament lamp or an elongated flurorescent or other radiant tube extending either curved or straight in the desired plane of illumination. One or both ends of the capsule might be illuminated with the elongated light sources separate from that used to illuminate the side of the capsule. Also, instead of using an elongated light source, one might use an elongated series of separate light sources to produce a somewhat similar result. The accompanying claims are intended to cover such variations of our invention.

We claim:

1. An optical system for inspecting medicinal capsules or the like having longitudinally curved surfaces, while each capsule is spinning on its axis in an inspection position, comprising an optical viewing system including one or more viewing lenses arranged to form at their image planes an image representation of an inspection area of the capsule surface, which area includes both a side surface of the capsule and a longitudinally curved end surface at at least one end of the capsule,

an illumination system including light source means for directing light rays on to said inspection area for specular reflection therefrom into said viewing system, with said light rays emanating from a plurality of points in a light source area which extends endwise of the capsule over a wide are that wraps around at least one end of the capsule, so as to produce on the capsule as seen by the viewing system a glare line area of specular reflection which includes both a linear side portion on the side of the capsule and a lineal end portion over an elongated are on the longitudinally curved end surface of the capsule, and

photo detector means responsive to light in said image representation over one or more areas thereof in spaced relation to the position of said glare line area therein.

2. An optical inspection system as in claim 1 in which the side and end of the capsule is illuminated from a single continuous light source area extending along side the capsule and around at least one end thereof.

3. An optical inspection system as in claim 2 in which said light source area comprises a reflective surface which lies transverse to a plane containing the axis of the capsule and extends in said plane through an arc endwise about the capsule, and means to supply light for reflection from said surface on to the capsule.

4. An optical system as in claim 3 in which said reflective surface extends in said plane through a substantially elliptical arc having one of its foci adjacent to the capsule, and a light source adjacent to its other focus.

5. An optical inspection system as in claim 4 in which said reflective surface is substantially in the form of an ellipsoidal surface about said two foci.

6. An optical inspection system as in claim 5 in which said light source means is an incandescent filament not centered on said other focus.

7. An optical inspection system as in claim 1 in which said light source area is of substantially uniform width along its length endwise of the capsule and is narrow circumferentially of the capsule so as to limit the width of the glare line area produced by specular reflection therefrom into said viewing system.

8. An optical inspection system as in claim 5 in which said ellipsoidal reflective surface is a narrow elongated band cut from the ellipsoid at an angle to its axis of revolution.

9. An inspection system as in claim 1 in which said light source means illuminates said inspection area sub stantially uniformly over its entire length.

10. An optical inspection system as in claim 1 in which the light rays from said inspection area which is thin transversely of the capsule and elongated endwise of the capsule, and in which the rays converge toward the capsule over a wide angle in the plane of elongation of the beam.

11. An optical inspection system as in claim 1 in which said viewing system includes a side-viewing lens arrayed to form an image of a side-surface portion of the capsule, and an end-viewing lens arrayed to form an image of an end-surface portion of the capsule.

12. An optical inspection system as in claim 10 in which said viewing system includes a side-viewing lens arrayed to form an image of a side-surface portion of the capsule, and an end-viewing lens arrayed to form an image of an end-surface portion of the capsule.

13. An optical inspection system as in claim 11 in which the end-viewing lens is arranged to view the capsule end-on.

14. An optical inspection system as in claim 13 with the addition of a mirror opposite the end of the capsule, the end-viewing lens being positioned with its axis at an angle to the capsule axis and viewing the capsule through said mirror.

15. An optical inspection system as in claim 1 in which said viewing system includes a side-viewing lens and two end-viewing lenses, and said inspection area includes longitudinally curved end surfaces at both ends of the capsule,

said side viewing lens being arrayed so as to form an image of an inspection area extending the full length of the capsule side and including an image of the glare line area on the side of the capsules and each end-viewing lens being arrayed so as to form an image of an inspection area at one end of the capsule which includes an image of the lineal glare area extending over an elongated arc of the curved end surface of the capsules,

the glare line areas imaged by the three lenses form ing a composite image extending substantially the full length of the capsule, whereby the entire surface of the capsule is inspected simultaneously.

16. An optical inspection system as in claim 1 in which the photo detector means includes at least one detector responsive to light in a capsule end image and at least one detector responsive to light in a capsule side image.

17. An optical inspection system as in claim in which the photo detector means includes separate photo detector devices responsive to light in the separate end and side images respectively.

18. An optical inspection system as in claim 1 in which said inspection area includes a substantial portion of the side surface of the capsule, and said photo detector means includes a plurality of detectors responsive to light from different portions of said side surface.

19. An optical inspection system as in claim 1 in which said viewing system includes a side viewing lens and two end viewing lenses, said lenses being arrayed to form separate inspection-area images which together form a composite image of an inspection area extendin g substantially continuously the full length of the capsule and over its longitudinally curved ends, and said photo detecting means including a plurality of detectors responsive to light in different portions lengthwise of said composite inspection area image.

20. An optical inspection system as in claim 19 in which said capsule intermediate its ends includes one or more built-in deviations, there being a photo detector separate from the others which is responsive to light in an inspection area portion in which such deviations appear.

21. An optical inspection system as in claim 1 in which the capsule includes one or more built-in deviations which produce a light variation similar to that of a defect, there being a separate photo detector responsive to light in the inspection area in which such deviations occur, the inspection results from said detector being processed to determine whether additional light variations occur to indicate the presence of such a defect.

22. Optical inspection apparatus for inspecting medicinal capsules or the like, comprising means to support and rotate each capsule on its axis in an inspection position with its ends exposed axially and its side exposed laterally for inspection,

a side-viewing lens system having its axis normal to the axis of the capsule axis,

at least one end viewing lens system having its axis at an angle to the capsule axis and positioned at the same side of the capsule as said side-viewing lens system, and a mirror on the axis of the capsule and disposed to reflect an end-on view thereof into said end-viewing lens system.

23. Optical inspection apparatus as in claim 22 which comprises an end-viewing lens system for each end of the capsule, mounted with their axes parallel with the axis of the side viewing lens system and in the same plane therewith, and a mirror on the axis of the capsule at each end thereof disposed to reflect into the end viewing lens system end-on views of the two ends of the capsule.

24. Optical inspection apparatus as in claim 23 further comprising an illumination system including a light originating source and a reflective surface transverse to a plane at a dihedral angle to the plane of said lens system and extending in said plane through a wide are which wraps around the ends of the capsule, said surface being disposed and shaped to reflect light from said source onto said capsule in a narrow elongated beam of converging rays.

25. Optical inspection apparatus as in claim 24 in which said reflective surface extends in said plane in an arc of an ellipse having one focus adjacent said light source and the other focus adjacent said capsule.

26. Optical inspection apparatus as in claim 25 in which said reflective surface is a strip-shaped section of an ellipsoidal surface.

27. Optical inspection apparatus as in claim 22 in which said dihedral angle is approximately 50, and said side-viewing lens projects an image of said capsule and of a glare line area thereon, and light sensing means at the plane of said image for sensing light in an elongated narrow area of the capsule image at one side of the glare line area thereon and responsive to specular reflection from capsule surface irregularities, and a second light sensing means for sensing light variations in an area of the image on the opposite side of the glare line area thereof.

28. Medicinal-capsule inspection apparatus, comprising means for spinning successive capsules on their axis in an inspection position, means for illuminating the capsules by intense light originating at a single lamp filament and reflected onto the capsule from a mirror in the form of a narrow band cut from an ellipsoid and positioned so that the filament is adjacent to one focus and the capsule adjacent to the other focus, and wherein the mirror wraps around the capsule endwise and produces on the capsule, as seen by a side-viewing lens and two end-viewing lenses, a narrow well-defined and continuous glare line area which curves over the ends substantially to the axis of the capsule, lenses projecting images of the capsule in side and end elevation on to masks at the image planes thereof which block the glare light from acceptable capsules, but contain apertures in spaced relation to the image glare light areas, which pass light specularly reflected from defects in selected observation areas on the spinning capsules, and light sensors behind the apertures to generate electrical control signals which provide inspection output information.

29. An optical system for inspecting medicinal capsules or the like having a generally cylindrical side surface, while each capsule is spinning on its axis at an inspection position, comprising,

a side viewing lens system having its axis substantially in a viewing plane containing the axis of the capsule and arranged to form at an image plane an image of the side of the capsule,

an illumination system including light source means for directing light rays on to the capsule in the direction of a lighting plane containing the capsule axis and at a dihedral angle to said viewing plane so as to produce specular reflection into said viewing system from a glare line area extending lengthwise of the capsule substantially within said dihedral angle, said glare line area being included in said capsule image,

first photo detector means responsive to light in a narrow area of said capsule image representing a first viewing area on the capsule at that side of said glare line area thereon toward said illumination plane,

whereby to sense capsule surface irregularities by specular reflection therefrom at angles greater than that from said glare line area.

30. An optical inspection system as in claim 29 further comprising second photo detector means responsive to light in a limited area of the capsule image representing a second viewing area on the capsule remote from the glare line area thereon and on the opposite side of the viewing plane from the glare line area, whereby to sense light reflected from the edges of longitudinal splits and the like in said capsule.

31. An optical inspection system as in claim 30 wherein said dihedral angle is approximately 50.

32. An optical inspection system as in claim 30 wherein said first and second viewing areas are substantially in the same focal plane of the viewing lens system.

33. An optical inspection system as in claim 29 in which said first detector means comprises a plurality of light sensing elements responsive respectively to different portions of the light of said glare line area.

34. An optical inspection system as in claim 29 wherein said illumination system comprises light source means for directing on to the capsule light rays emanating from a light source area which extends endwise of the capsule over a substantial distance beyond the ends of the capsule so as to converge toward the capsule in the said illumination plane,

said light source area being of uniform narrow width in the direction normal to said illuminating plane to delineate the glare line area on the capsule as a uniform narrow area. 35. An optical inspection system as in claim 29 wherein said illumination system comprises light source means for directing on to the capsule light rays emanating from a plurality of points in a light source area which extends endwise of the capsule over a wide arc in said illumination plane so that such rays converge on to said capsule from a wide angle in said illumination plane.

36. An optical system for inspecting medicinal capsules or the like having a generally cylindrical side surface, while each capsule is spinning on its axis at an inspection position, comprising a side-viewing lens arranged to form at an image plane an image of the side surface of the capsule,

an illumination system including light source means for directing light rays on said capsule for specular reflection into said viewing system from a narrow glare line area extending over substantially the whole length of the capsule side,

and photo detector means responsive to light in said image over an elongated narrow viewing area parallel with and separate from the image of said glare line area therein,

said detector means including a plurality of light sensing elements respectively responsive to light variations at different portions of the length of said viewing area.

37. An optical inspection system as in claim 36 wherein said light source means directs on to the capsule light rays emanating from a light source area which extends endwise of the capsule over a wide are so that such rays converge on to the capsule from a wide angle, whereby to improve observation of surface variations in the vicinity of said glare line area.

38. An optical system for inspecting capsules or like inspection workpieces having a spherical or other convex surface of revolution of a convexly curved line about an axis, while the workpiece is rotated on its axis of revolution, comprising an optical viewing system for viewing the convex surface from a predetermined direction,

an illumination system including light source means for directing light rays on to said convex surface for specular reflection therefrom into said viewing system,

said rays converging on to said convex surface from a plurality of points in a light source area distributed in a wide are which wraps around said convex surface, so as to produce on said surface as seen by said viewing system a glare line area of specular reflection extending over an elongated arc on said convex surface,

said optical viewing system including means for sensing light variations in a viewing area of the thus-illuminated convex surface as the workpiece is rotated.

39. An optical inspection system as in claim 38 in which said arclies substantially in a plane containing the axis of rotation of the workpiece.

40. An optical inspection system as in claim 38 in which said viewing system views the workpiece in the direction of its axis of revolution.

41. An optical inspection system as in claim 39 in which said viewing system views the workpiece in the direction of its axis of revolution.

42. An optical inspection system as in claim 38 in which said light source area is of substantially uniform narrow width in the direction normal to the plane of said arc, so as to limit said glare line area to a narrow linear area.

43. An optical inspection system as in claim 38 in which said light source area comprises a reflective sur face extending in an are about said convex surface, and means to supply light to said reflective surface for reflection on to said workpiece.

44. An optical inspection system as in claim 38 further comprising a light originating element, said light source area comprising a reflective surface extending in an are about said workpiece surface and disposed to receive light from said element and reflect the same in converging rays on to said convex surface.

45. An optical inspection system as in claim 44 in which said reflective surface extends in an elliptical arc having one focus adjacent the light originating element and the other focus adjacent the workpiece surface.

46. An optical inspection system as in claim 45 in which said reflective surface is a section of an ellipsoid.

47. An optical inspection system as in claim 44 in which said reflective surface extends in an arc of a conic section.

48. An optical inspection system as in claim 44 in which said reflective surface is a portion of a surface of revolution of a conic section.

49. An optical inspection system as in claim 38 in which said viewing area is an elongated area beside and separate from said glare line area.

50. An optical inspection system as in claim 39 in which said glare line area as seen by the axial viewing system is a generally radial area and the viewing area includes radial areas on both sides of the glare line area.

51. An optical inspection system as in claim 50 in which the viewing area includes an area diametrically opposite from said glare line area.

l i i t

Claims

1. An optical system for inspecting medicinal capsules or the like having longitudinally curved surfaces, while each capsule is spinning on its axis in an inspection position, comprising an optical viewing system including one or more viewing lenses arranged to form at their image planes an image representation of an inspection area of the capsule surface, which area includes both a side surface of the capsule and a longitudinally curved end surface at at least one end of the capsule, an illumination system including light source means for directing light rays on to said inspection area for specular reflection therefrom into said viewing system, with said light rays emanating from a plurality of points in a light source area which extends endwise of the capsule over a wide arc that wraps around at least one end of the capsule, so as to produce on the capsule as seen by the viewing system a glare line area of specular reflection which includes both a linear side portion on the side of the capsule and a lineal end portion over an elongated arc on the longitudinally curved end surface of the capsule, and photo detector means responsive to light in said image representation over one or more areas thereof in spaced relation to the position of said glare line area therein.

9. An inspection system as in claim 1 in which said light source means illuminates said inspection area substantially uniformly over its entire length.

15. An optical inspection system as in claim 1 in which said viewing system includes a side-viewing lens and two end-viewing lenses, and said inspection area includes longitudinally curved end surfaces at both ends of the capsule, said side viewing lens being arrayed so as to form an image of an inspection area extending the full length of the capsule side and including an image of the glare line area on the side of the capsules and each end-viewing lens being arrayed so as to form an image of an inspection area at one end of the capsule which includes an image of the lineal glare area extending over an elongated arc of the curved end surface of the capsules, the glare line areas imaged by the three lenses forming a composite image extending substantially the full length of the capsule, whereby the entire surface of the capsule is inspected simultaneously.

17. An optical inspection system as in claim 15 in which the photo detector means includes separate photo detector devices responsive to light in the separate end and side images respectively.

19. An optical inspection system as in claim 1 in which said viewing system includes a side viewing lens and two end viewing lenses, said lenses being arrayed to form separate inspection-area images which together form a composite image of an inspection area extending substantially continuously the full length of the capsule and over its longitudinally curved ends, and said photo detecting means including a plurality of detectors responsive to light in different portions lengthwise of said composite inspection area image.

22. Optical inspection apparatus for inspecting medicinal capsules or the like, comprising means to support and rotate each capsule on its axis in an inspection position with its ends exposed axially and its side exposed laterally for inspection, a side-viewing lens system having its axis normal to the axis of the capsule axis, at least one end viewing lens system having its axis at an angle to the capsule axis and positioned at the same side of the capsule as said side-viewing lens system, and a mirror on the axis of the capsule and disposed to reflect an end-on view thereof into said end-viewing lens system.

23. Optical inspection apparatus as in claim 22 which comprises an end-viewing lens system for each end of the capsule, mounted with their axes parallel with the axis of the side viewing lens system and in the same plane therewith, and a mirror on the axis of the capsule at each end thereof disposed to reflect into the end-viewing lens system end-on views of the two ends of the capsule.

24. Optical inspection apparatus as in claim 23 further comprising an illumination system including a light originating source and a reflective surface transverse to a plane at a dihedral angle to the plane of said lens system and extending in said plane through a wide arc which wraps around the ends of the capsule, said surface being disposed and shaped to reflect light from said source onto said capsule in a narrow elongated beam of converging rays.

27. Optical inspection apparatus as in claim 22 in which said dihedral angle is approximately 50*, and said side-viewing lens projects an image of said capsule and of a glare line area thereon, and light sensing means at the plane of said image for sensing light in an elongated narrow area of the capsule image at one side of the glare line area thereon and responsive to specular reflection from capsule surface irregularities, and a second light sensing means for sensing light variations in an area of the image on the opposite side of the glare line area thereof.

29. An optical system for inspecting medicinal capsules or the like having a generally cylindrical side surface, while each capsule is spinning on its axis at an inspection position, comprising, a side viewing lens system having its axis substantially in a viewing plane containing the axis of the capsule and arranged to form at an image plane an image of the side of the capsule, an illumination system including light source means for directing light rays on to the capsule in the direction of a lighting plane containing the capsule axis and at a dihedral angle to said viewing plane so as to produce specular reflection into said viewing system from a glare line area extending lengthwise of the capsule substantially within said dihedral angle, said glare line area being included in said capsule image, first photo detector means responsive to light in a narrow area of said capsule image representing a first viewing area on the capsule at that side of said glare line area thereon toward said illumination plane, whereby to sense capsule surface irregularities by specular reflection therefrom at angles greater than that from said glare line area.

31. An optical inspection system as in claim 30 wherein said dihedral angle is approximately 50*.

34. An optical inspection system as in claim 29 wherein said illumination system comprises light source means for directing on to the capsule light rays emanating from a light source area which extends endwise of the capsule over a substantial distance beyond the ends of the capsule so as to converge toward the capsule in the said illumination plane, said light source area being of uniform narrow width in the direction normal to said illuminating plane to delineate the glare line area on the capsule as a uniform narrow area.

35. An optical inspection system as in claim 29 wherein said illumination system comprises light source means for directing on to the capsule light rays emanating from a plurality of points in a light source area which extends endwise of the capsule over a wide arc in said illumination plane so that such rays converge on to said capsule from a wide angle in said illumination plane.

36. An optical system for inspecting medicinal capsules or the like having a generally cylindrical side surface, while each capsule is spinning on its axis at an inspection position, comprising a side-viewing lens arranged to form at an image plane an image of the side surface of the capsule, an illumination system including light source means for directing light rays on said capsule for specular reflection into said viewing system from a narrow glare line area extending over substantially the whole length of the capsule side, and photo detector means responsive to light in said image over an elongated narrow viewing area parallel with and separate from the image of said glare line area therein, said detector means including a plurality of light sensing elements respectively responsive to light variations at different portions of the length of said viewing area.

37. An optical inspection system as in claim 36 wherein said light source means directs on to the capsule light rays emanating from a light source area which extends endwise of the capsule over a wide arc so that such rays converge on to the capsule from a wide angle, whereby to improve observation of surface variations in the vicinity of said glare line area.

38. An optical system for inspecting capsules or like inspection workpieces having a spherical or other convex surface of revolution of a convexly curved line about an axis, while the workpiece is rotated on its axis of revolution, comprising an optical viewing system for viewing the convex surface from a predetermined direction, an illumination system including light source means for directing light rays on to said convex surface for specular reflection therefrom into said viewing system, said rays converging on to said convex surface from a plurality of points in a light source area distributed in a wide arc which wraps around said convex surface, so as to produce on said surface as seen by said viewing system a glare line area of specular reflection extending over an elongated arc on said convex surface, said optical viewing system including means for sensing light variations in a viewing area of the thus-illuminated convex surface as the workpiece is rotated.

39. An optical inspection system as in claim 38 in which said arc lies substantially in a plane containing the axis of rotation of the workpiece.

43. An optical inspection system as in claim 38 in which said light source area comprises a reflective surface extending in an arc about said convex surface, and means to supply light to said reflective surface for reflection on to said workpiece.

44. An optical inspection system as in claim 38 further comprising a light originating element, said light source area comprising a reflective surface extending in an arc about said workpiece surface and disposed to receive light from said element and reflect the same in converging rays on to said convex surface.