US2867916A - Apparatus for optically mixing colors - Google Patents

Description

Jan. 13, 1959 s. H. BIRDSEYE APPARATUS FOR OPTICALLY MIXING COLORS 2 Sheets-Sheet 1 Filed Oct. 19, 1954 Sidney H. Birdseye IN VEN TOR.

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Jan. 13, 1959 s. H. BIRDSEYE APPARATUS FOR OPTICALLY MIXING COLORS Filed Oct. 19, 1954 2 Sheets-Sheet 2 N% wk h t wk on mm mm .m\ C y R mm mm an Sidney hf Birdseye INVENTOR.

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Auorn United States Patent 2,8618% Patented Jan. 13, 1959 2,867,916 APPARATUS FOR OPTICALLY MIXING COLORS Sidney H. Birdseye, Arlington, Va., assignor of fifty percent to Bertram Michael Landemann,

. Application October 19, 1954, Serial No. 463,155

4 Claims. (Cl. 35-19) thereby adjusting the intensity of the various colored lights which permits the mixing of these lights into a resultant color tint of spectral quality.

Another object of the present invention isto provide an apparatus for optically mixing colors which will provide various shades of tinted colors on a viewing screen or ground lens, thereby permitting the formation of colors with a desired, spectral tint.

A still further object of the present invention is to provide an apparatus for optically mixing colors conformable to the preceding objects wherein the variable density scale is calibrated so that the relative intensity of the various colors may be determined for reference purposes. 7

Still another important object of the present invention is to provide an apparatus for optically combining colors which is simple in construction, easy to use, adaptable for various uses and purposes and relatively inexpensive to manufacture.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation, as more fully hereinafter described and claimed, reference ,being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure 1 is a side elevational view of the apparatus utilized in optically mixing colors with portions thereof broken away showing various details of construction;

Figure 2 is a top plan view of the construction of Figure 1 showing the relationship of various elements of the invention;

Figure 3 is a transverse, vertical sectional view taken substantially upon the plane, passing along section line 33 of Figure 1 showing the details of construction of the density scale reels;

Figure 4 is a detailed sectional view taken substantially upon a plane passing along section line 44 of Figure 2 showing the details of construction of the color filter holder and the guide for the variable density scale;

Figure 5 is a perspective view showing the construction of one of the color filters; and

Figure 6 is a fragmentary perspective view showing the construction of the density scale having blocks thereon of varying degrees of opaqueness.

Referring now specifically to the drawings, it will be seen that the numeral 10 generally designates the apparatus for optically combining and mixing colors of the present invention. The apparatus 10 generally includes a; supporting base 12 of any desirable rectangular con figuration which is provided at one end thereof with an upstanding and inverted U-shaped supporting bracket 1.4 havinga socket 16 receiving a projector-type light bulb 18 therein. A suitable electrical conductor 20 is at- Washington,

tached to the socket 16 and an on-and-ofi switch 22 is provided for controlling the electrical current to the light source 18. A casing 24 is provided forwardly of the light source 18 and may be of any desirable opaque construction' and positioned behind the light source 18 is a parabolic reflector 26 having a suitable reflective surface on the inner surface thereof.

Positioned in a horizontal plane and extending through the casing 24 in a radial position are three rods 28, 30 and 32 which are constructed of. plastic material, such as Lucite, which transmits light from the source of light 18 along the longitudinal length of the rods 28, 30 and 32, wherein the rods 28, 30 and 32 extend in a horizontal plane with the outer rods 28 and 32 diverging and then extending in parallel spaced relation to the center rod 30. The other ends of the rods 28, 30 and 32 converge with the outer rods 28 and 32 converging towards the center rod 30, wherein they terminate in a Lucite collecting rod 34 which is larger than the rods 28, 30 and 32. Positioned at the forward end of the Lucite rod 34 is a projecting lens 36 which is removably positioned thereon by a screw threaded cap 38 which permits removal or replacement of the projecting lens 36.

The Lucite collecting rod 34 used to mix colors is supported on an upstanding bracket 40 which terminates in a U-shaped portion 42 which engages and supports the Lucite rod 34. The inner end of the Lucite rod 34 is positioned in a split cap 44 having clamp screws 46 detachably clamping the Lucite rod 34 in the split cap 44. With this particular construction, it will be noted that both the lens 36 and the Lucite member 34 may be removed and changed as desired.

Positioned centrally in each of the rods 28, 30 and 32 is a color filter holder and a density scale holder generally designated by the numeral 48, the details of which are illustrated in Figure 4.

Referring specifically to the holder 48, it will be see that this device is generally formed in a tubular polygonal sleeve 50 having an entrance slot 52 for slidably and removably positioning a primary optical color filter 54 which may be straight or provided with an offset handle. The rod 30 as Well as the other rods are sectional and terminate in an enlarged polygonal collar 56 and the filter 54 is positioned between the. enlarged collarv 56 on one portion of the rod 30, and the enlarged collar 58 on the other portion of the rod 30 wherein light will pass through the filter 54 along the rod 38. Extending integrally from the upper and lower surface of the sleeve 50 is a tubular guide 60 for receiving a movable density scale 62 which is positioned forwardly of the color filter 54. The density scale ,62 is'provided with a series of blocks 64 of varying degrees of opaqueness or transparency wherein the intensity of the light passing through the color filter 54 may be varied. The tubular member 60 extending upwardly and downwardly from the sleeve 50 terminates in cylindrical housings 66 and 68, with one of the cylindrical housings 66 being positioned above the rod and one of the housings 68 being positioned below the cylindrical rod 30.

The upper cylindrical housing 66 is provided with a re movable cap 78 and a central handle and shaft 72 on which a reel 74 is positioned for receiving the density scale 62. The lower cylindrical housing 68 is provided with a removable cap 76 having a cylindrical reel 78 mounted therein for receiving the density scale 62. The reel 78 is secured to a rotatable shaft 80 which projects outwardly of the cap 76 and is provided with a pointer 82 thereon for registry with indicia 84 on the outer surface of the lower cap 76, thereby calibrating the density scale 62 on the calibrated indicia 84 for determining the position of the density scale so that the relative intensity of the light passing through each of the rods 28, 30, and

32 may be determined. It is noted that each of the rods 28, 30 and 32 is provided with an identical structure for a supporting a color filter and supporting the movable density scale 62. It is'noted that the color filter 62 ,on

the rods 28 and 32 is removable from the side while the color filter 62 on the central rod 30 is removable from the top.

.The upper and lower reel housing 66 and 68 are supported from rear brackets 86 and a forward bracket 88 is provided for supporting the housing 66and .68 in proper relation to the central rod 30. The bracket 38 is positioned forwardly of the brackets 86.

In operation, the light from the light source 18 passes along the transmission rods 28, 30 and 32 through the color filters 54 which may be of any of the primary colors and then through the density scale 62 which varies the intensity of the light passing along-the rods 28, 30 and 32. This varies the intensity of the prime colors and the light then passes into the collecting rod 34 and is projected by the lens 36 onto a suitable viewing area, or the device may be utilized with a glass screen for forming a viewing area substantially in the plate of the projecting lens 36.

If desired, the entire device may be covered with a removable cover 90, and the source of light may be ventilated, and the particular structural details for mixing colors has been previously described.

The white light maybe transmitted from the source through the primary color filters and the density gray scales by use of tubes employing a series of mirrors therein or any suitable system of lenses, prisms or combination thereof, and then, projecting the tints from the hollow tubes. It will be understood that a minimum of three primary colors are to be used and it may be advisable to add one or more secondary colors with accompanying transmission means such as rods or tubes plus color filters and density scales.

It will be understood that the device may be utilized in any particular orientation in which it is desirable to mix colors for various purposes where resultant tints of true spectral quality are essential, such as comparative analysis, interior decoration, testing purposes, metallurgical heat testing and control, and paint manufacture. The scale may be calibrated to set up various standards and by computing various problems with these standards, it will be possible to establish a test and analysis procedure.

From the foregoing, the construction and operation of thejdevice will be readily understood and further explanation is believed to be unnecessary. However, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the appended claims.

What is claimed as new is as follows:

1. A color mixing device comprising a source of light, means for transmitting the light along a plurality of paths, means for coloring the light in each path, means for varying the intensity of the colored light in each path, and means for converging and projecting the colored light thereby forming a variable resultant color, said means for converging and projecting the colored lights including a solid collecting and mixing rod for projecting the mixed colors onto a viewing area in true spectral quality.

2. A color mixing device comprising a source of light, means for transmitting the light along a plurality of paths, means for coloring the light in eachpath, means for varying the intensity of the colored light in each path, and means for converging and projecting the colored light thereby forming a variable resultant color of true spectral quality, said light transmitting means including a plurality of light transmitting rods, said rods extending radially from said light source in a plurality of parallel paths, said rods converging radially inwardly remote from said light source for directing the light toward a common projection point, said means for coloring the light including a removable color filter positioned in each path of light, said filters imparting prime color to the light, said filters being insertable for changing the color of each light path, said means for varying the intensity of the light in each path including a movable density scale positioned adjacent the coloring means for varying the intensity of the light after it has been colored, said scale being wound on reels on opposite sides of said path of light for positioning selective areas of the density scale in the path of light, and a calibrated scale on one of said reels for indicating the portion of the scale in the path of light thereby determining the intensity of the light.

3. A color mixing device comprising a source of light, means for transmitting the light' along a plurality of paths, means for coloring the light in each path, means for varying the intensity of the colored. light in each path, and means for converging and projecting the colored light thereby forming a variable resultant color,

said light transmitting means including a plurality. of light transmitting rods, said rods extending radially from said light source'and bending the light to travel in a plurality of parallel paths, said rods converging v radially inwardly remote from said light source for directing the light toward a common projection point, said means for coloring the light including a removable color filter positioned in each path of light, said filters imparting prime color to the light, said filters being insertable for changing the color-of each light path, said means for varying the intensity of the lightin each path including a movable density scale positioned adjacent the coloring means for varying the intensity of the light after it has been colored, said scale being'wound on reels on opposite sides of said path-of light for positioning selective areas of the density scale in the path'of light, and a calibrated scale on one of said reels for indicating the portion of the scale in the path of light thereby determining the intensity of the light, said means for converging and projecting the colored lights including a solid collecting and mixing rod for projecting the mixed colors onto a viewing area in true spectral quality.

4. A device for optically mixing primary colors and producing color tints of true spectral quality comprising a source of white light of substantially constant intensity, a plurality of light transmitting rods receiving light from said source, a removable prime color filter References Cited in the file of this patent I UNITED STATES PATENTS ,091 Parsons -L. June 21, 1932 1,981,999 French Aug. 20, 1932 72.646 Schmidt Feb. 10, 1942 67 Ford .a July 25, 1944 2,431,091 Thomas NOV. 18, 1947 91 Morrison a, Jan; 10, 1950 2,589,569 ,Peter Mar. 18, 1952 :OTHER REFERENCES p g Light With Acrylic Materials by Henry Pear- O rMQdern .stics, August 1946, pp. 123-127..

and bending the light to travel

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