US3756696A

US3756696A - Optical image transfer apparatus

Info

Publication number: US3756696A
Application number: US00205574A
Authority: US
Inventors: C Gardiner
Original assignee: Itek Corp
Current assignee: Northrop Grumman Guidance and Electronics Co Inc
Priority date: 1971-12-07
Filing date: 1971-12-07
Publication date: 1973-09-04
Anticipated expiration: 1990-09-04
Also published as: CA976394A; JPS4865954A; GB1417412A; DE2259936A1

Abstract

A method and apparatus for transferring a plurality of characters from a first medium wherein said characters are arranged in a first array to a second medium wherein the same characters are rearranged into a second array different from the first array. The technique employs an arrangement of mirrors or other optical elements positioned to optically divide the first array of characters into a plurality of segments and to then reassemble those segments together into the second array. The system is particularly designed for use in Computer-OutputMicrofilm recording units to transfer data from the face of an inexpensive cathode ray tube readout display to microfilm but may also be employed in many other image transfer operations. Large expensive CRT readout displays are thus eliminated for COM operations.

Description

United States Patent 1 Gardiner OPTICAL IMAGE TRANSFER APPARATUS [75] lnventor: Charles W. Gardiner, Manchester,

[21] Appl. No.: 205,574

[52] US. Cl. 350/169 [51] Int. Cl. G02b 27/10 [58] Field of Search 350/169, 171, 172

[ 56] References Cited UNITED STATES PATENTS 2,627,199 2/1953 O'Brien 350/169 2,207,236 7/1940 Uden .1 355/46 2,390,439 12/1945 Johnson 350/291 2,727,428 12/1955 Herman 350/304 X 2,900,884 8/1959 Coleman.... 350/172 X 3,216,317 11/1965 Nail 350/301 X 3,564,128 2/1971 Hosterman 178/63 [111 3,756J696 [451 Sept. 4, 1973 Primary ExaminerDavid H. Rubin Atlorney- Homer Q Blair Robert L. Nathans et a1.

[57] ABSTRACT A method and apparatus for transferring a plurality of characters from a first medium wherein said characters are arranged in a first array to a second medium wherein the same characters are rearranged into a second array difierent from the first array. The technique employs an arrangement of mirrors or other optical elements positioned to optically divide the first array of characters into a plurality of segments and to then reassemble those segments together into the second array. The system is particularly designed for use in Computer-Output-MicrofilirT recording units to transfer data from the face of an inexpensive cathode ray tube read out display to microfilm but may also be employed in many other image transfer operations. Large expensive CRT readout displays are thus eliminated for COM operations.

7 Claims, 7 Drawing Figures OPTICAL IMAGE TRANSFER APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical assembly for manipulating an array of characters. More particularly, the present invention relates to a method and apparatus for transferring characters from a first medium wherein the characters are arranged in a first array to a second medium wherein the same characters are rearranged into a second array different from the first array.

2. Description of the Prior Art In all computer installations, some type of output system must be provided to enable the computer effectively to communicate with the outside world. Of the various systems available, probably the most common is a line printer with which the computer may print out its response on paper. In addition to a line printer, however, many computer systems also include equipment for recording the output on microfilm. These devices are known in the art as Computer-Output-Microfilmrecorders, or, more generally, as COM units. Conventionally, they consist of a cathode ray tube for displaying the output data from the computer, and a microfilm camera for photographing the display directly from the face of the tube.

Often, it is desirable to utilize both a line printer and a COM unit so that the computer's response may be placed on paper for immediate use or review and simultaneously placed on microfilm for more permanent and economical storage. Futherrnore, it is generally desirable that both the printed and the microfilmed infonnation be maintained in the same format, and it is in this respect that most systems are not fully satisfactory.

The reason for this deficiency is the fact that most line printers are designed to print as many as 132 alphanumeric characters on a single line and, as a result, it is also desirable to be able to record the same 132 character line on the microfilm. Conventional cathode ray tubes, as employed in home television sets, however, simply do not have the resolution to display 132 characters on a single line and, accordingly, it has been necessary to employ much more expensive and sophisticated CRT's that do have the required resolution. Such tubes are extremely expensive and may cost several thousands of dollars. Conventional T.V. tubes, on the other hand, only cost a few dollars and if they could be effectively used, the cost of COM units would be reduced significantly. It is toward this goal that the present invention is primarily directed.

Basically, although a conventional T. V. tube does not have sufficient resolution to display 132 alphanumeric characters on a single line, it is capable of displaying that many characters over its entire surface. Therefore, if a suitable optical system can be provided to assemble the characters displayed on the screen into one long line for recordation on the microfilm, the effective resolution of the T.V. tube may be increased sufficiently to enable its use in a COM unit.

In U.S. Pat. No. 3,564,128 to Harry L. I-Iosterman, a technique for optically assembling two lines displayed on the face of a CRT into one line for recordation on film is described. This sytem, however, suffers from several significant disadvantages making it unsuitable for use in COM units. Initially, the optics would become quite complex when attempts are made to combine more than two lines into one line and this would be necessary in a COM unit as well as in many other applications. Furthermore, displays on inexpensive cathode ray tubes are subject to drift due to variations in power, magnetic fields and the like, and; in the above cited patent, such drift, particularly vertical drift, can seriously affect the positioning of the final assembled image and prevent the two lines on the TV. screen from being placed in perfect alignment on the film.

In general, what is needed is a system that can take a plurality of lines that are displayed on the face of a cathode ray tube and optically realign them into one single line for recordation on film. The system must be simple, compact, easy to position, and unaffected by normal image drift on the T.V. screen. Furthermore, it must provide a high quality image on the film.

SUMMARY OF THE PREFERRED EMBODIMENT In accordance with the present invention, many of the abovementioned problems have been substantially overcome by providing an optical system which can effectively assemble a plurality of lines of characters into a single line for recordation on film or for other purposes. In accordance with a preferred embodiment, the system employs an arrangement of mirrors capable of optically dividing an array of characters into segments and then reassembling those segments to form them into a second array. By slight modification of the system, the structure can also be used to convert one line into a plurality of lines as well as perform a myriad of other manipulations to produce desired character arrays.

Besides being much more versatile than systems employed in the prior art, the present system also overcomes many of the problems found therein. Initially, it is not as sensitive to image drift as many prior art devices and in general, slight amounts of drift will not affect the alignment of the final image. Furthermore, the system is quite simple in design and will not become unduly complex as the number of lines being manipulated increases. Also, it may be assembled and positioned with little difficulty and requires a minimum number of components. Finally, it is constructed of common, inexpensive materials making it readily usable in a wide variety of image transfer operations.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I illustrates, in schematic form, a top view of the optical system of the present invention employed in conjunction with a COM unit.

FIG. 2 illustrates the optical system of the present invention looking in the direction of arrows 22 in FIG. 1.

FIG. 3 illustrates an image displayed on the face of the cathode ray tube of FIG. 1.

FIGS. 4 and 5 are provided to illustrate the operation of the optical system of the present invention.

FIG. 6 illustrates the realigned image which may be recorded on the microfilm of FIG. 1 and the manner in which that image may be produced.

FIG. 7 illustrates masking structure that may be employed with the optical system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT To enable a clear understanding of the present invention, it will be described hereinafter primarily as it might be employed in conjunction with a COM unit to transfer information from the screen of a cathode ray tube to microfilm. It should be clearly understood, however, that the invention is not limited to use in COM units but could just as readily be employed to transfer information between other mediums for a variety of other purposes. It should also be understood that the term characters" as used herein is not restricted to alphanumeric characters but may include any other type of symbol or indicia that it may be desired to rearrange.

FIG. I illustrates, in schematic form, a top view of a preferred form of the optical system of the present invention (generally designated by the reference number 1) being employed to transfer information from a CRT to microfilm. Reference number 2 refers to a cathode ray tube which in the preferred embodiment comprises a commerical TV monitor of conventional type. As described previously, a goal of the invention is to be able to record a line of I32 alphanumeric characters onto microfilm to correspond to the 132 character line of conventional line printers. As also explained previously, the face of a conventional T.V. tube does not have sufficient resolution to display that many characters on a single line, but it can adequately display four lines having 33 characters on each line. Thus, appropriate logic is provided in the COM unit (or alternatively, in the computer) to display the 132 character line printed out by the line printer in an array of four lines or segments aligned consecutively reading from left to right and from top to bottom in the normal manner. Such a display is illustrated in FIG. 3 wherein the face 3 of the CRT contains four lines 6-9 of 33 alphanumeric characters each (for ease of illustration, only eight characters are shown in each line).

In order to place the four lines 6-9 onto microfilm as one continuous line to correspond to the line printer output, the optical system 1 of the present invention is provided. As illustrated in FIG. 1, this system includes four sets of

mirror pairs

11a and 11b, 12a and 12b, 13a and 13b, and 14a and 14b suitably mounted by structure to be described hereinafter with reference to FIG. 2. The mirrors are positioned such that the image on the face 3 of the CRT will be reflected off of each mirror Ila, 12a, 13a and 14a onto

mirrors

11b, 12b, 13b and 1417, respectively, and then into a lens 16 incorporated in a microfilm camera 17.

Each of the two mirrors forming a mirror pair are aligned in parallel, and, as understood by those skilled in the art, act to shear" the image on the CRT face (i.e., displace it laterally without rotation as seen by the lens 16). As is also understood, the amount of image displacement is a function of the spacing between the mirrors and the angle between the mirrors and the CRT face. Thus, by properly positioning the four mirror pairs, it becomes a relatively simple matter to produce four images that are each identical to the image on the face of the CRT but displaced by different amounts. In practicing the present invention, the mirrors are positioned to place the four images in alignment and directly adjacent each other as illustrated in FIG. 4 wherein

images

3a, 3b, 3c, and 3d may be seen by lens 16.

In order to now assemble the initial four lines 6-9 into a single line for recordation on the microfilm 18 (FIG. 1) it is only necessary to displace the four images 3a-3d relative to each other such that line 6 in image 3a, line 7 in image 3b, line 8 in image 3c, and line 9 in image 3d will all be in alignment. This may readily be accomplished by independently rotating each of the four images by an amount sufficient to bring the appropriate line of each image into alignment as illustrated in FIG. 5. On doing this, a single line 19 is formed which consists of each of the four lines 6-9 of original image 3 arranged in the proper order.

The relative displacement between the images 3a 3d can be accomplished by tilting the TV face 3 through a small angle, in which case the camera lens 16 would see" the image shown in FIG. 5. In this arrangement, however, it would also be necessary to tilt the camera so that the film 18 would be aligned properly to position line 19 thereon as shown in FIG. 5.

It is preferable, therefore, to maintain both the CRT and the camera in their normal upright position and instead tilt the mirror assembly I. This is illustrated more clearly in FIG. 2 which is a view of the system of FIG. 1., looking in the direction of arrows 2-2 with portions removed for clarity. As can be seen, the mirrors are mounted on a support table 22 having appropriate legs 23 and 24 (only two of which are shown). The legs are adjstable in height to enable the table 22 and hence the mirrors to be tilted relative to the TV screen 3 and the camera (not shown). I have found that by properly choosing the angle of tilt, which will generally be around 6, an image as illustrated in FIG. 6 will be presented to the lens 16 of camera 17 wherein line 19 is aligned horizontally for recordation on film 18. In this regard, it should be pointed out that the images illustrated in FIG. 4 and 5 would never be actually presented to the lens 16 when the mirrors are tilted relative to the camera and T.V. screen as shown in FIG. 2 but that image in FIG. 6 is the one seen" by the lens. The images of FIG. 4 and 5 are illustrated simply for explanation of the invention. It should also be understood that the image in FIG. 6 is actually identical to that shown in FIG. 5 except for being tilted so that the line 19 will appear horizontal.

Inasmuch as it is desired to record only the single reassembled line 19 onto the film, and not the remaining segments shown in FIG. 6, appropriate masking structure must be provided to blank out the remaining portions of the image. This masking structure may take several forms. The simplest technique would be to simply position a small slit in the camera directly in front of the film plane such that only line 19 will be able to reach the film. This structure has certain disadvantages, however, because the slit must be made very thin and thus is susceptible to becoming clogged with dust and other debris. Accordingly, it is preferable to mount the masking device in the light path between the TV screen and the mirror assembly to permit the slits to be made much larger. This may be done fairly simply by providing a mask 26 as illustrated in FIG. 7 having four

separate slits

26a, 26b, 26c, and 26d. The slits are positioned such that only line 6 on the T.V. screen 3 will reach mirror lla, only line 7 will reach mirror 12a, only line 8 will reach mirror 13a, and only line 9 will reach mirror 140. As a result, only line 19 will appear on the film l8 and the remaining image segments shown in FIG. 6 for illustration purposes will be blocked out. Preferably, the mask 26 is positioned in the area shown schematically in FIG. I. If it were placed closer to the TV screen where the light beams intersect each other, positioning would be much more difficult.

By synchronizing the motion of the film (which would be perpendicuar and upward from the plane of FIG. I and in the direction 21 in FIG. 6) with the electron beam in the TV set, successive lines may be formed on the film in the same format that they are printed out on the line printer. Synchronizing circuitry for accomplishing this is well-known in the prior art and need not be detailed here.

Referring again to FIG. 6, it might be noted that independent rotation of the images 3a 3d to form the line I9 causes portions of certain characters, for example the I and the Q", to extend off of the particular image plane in which it was originally contained. It has been found, however, that these entire characters will still be visible to the lens 16 and may be recorded on the film. The reason for this phenomenon may be explained by the fact that what the lens actually sees" is a plurality of images which appear to originate from some point behind the mirrors. Thus, the mirrors 11b 14b may be considered to be the optical equivalents of four apertures allowing light from each image to reach the lens. Since each of these mirrors 11b 14b act as apertures, at least portions of the lens will receive light from the entire images and thus, the entire images will be seen" by the lens. Due to vignetting, however, these portions of the characters will not be as bright as other portions of the characters, but they are clear and sufficiently bright to form a good image on the film. This phenomenon is well understood by those skilled in the art and a more detailed discussion of the optical theory involved need not be discussed here. Suffice it to say that a clear image of line 19 may be readily recorded onto the microfilm 18 in its entirety.

The positioning of the mirrors to align the images in the prescribed manner is important but not particularly difficult. The basic requirements in this preferred embodiment is that the mirror pairs lla 11b, 12a 12b, and so forth be parallel to each other to act as shearing mirrors to displace the images laterally. By properly selecting the angles between the mirror pairs and the television screen the amount of lateral displacement can readily be adjusted. The mirrors should also be positioned such that they will not interfere with light beams reflected 011' of other mirrors. This again can be readily done with slight amount of experimentation. In general, the mirror pairs may be positioned in many different ways, both symmetrical and non-symmetrical, to achieve the same final image illustrated in FIG. 6.

What has been specifically described above is an optical system that can take four lines of characters and optically rearrange them into one single line for recor dation on film. By simply reversing the camera and the TV tube, one line of characters may also be converted into four lines without further modification of the system. By slight modifications other character manipulations may also be readily performed. It is also not necessary to use mirrors in the present invention. In some applications prisms or fiber optical bundles could also be employed to produce multiple images.

Although the invention has been described in conjunction with a COM unit for transferring information from a TV screen to film it may be readily emloyed in many other applications. For example, it may also find use in the facsimile field. In such equipment for example, the optical system of the present invention could be used to separate one long line of characters irito four lines to be picked up by an ordinary TV camera and sent over long distances to a TV receiver. Another optical system can then be provided at the receiver to reconvert the four lines into the original one line for recordation. Accordingly, it should be understood that numerous alterations, omissions, and additions may be made without departing from the spirit of the invention, and it should'be limited only as required by the scope of the following claims.

I claim:

I. Apparatus comprising:

a. a first medium having a first character array thereon, said first character array consisting of a plurality of substantially stationary characters arranged in a first number of lines;

b. optical means for optically multiplying said first character array to produce a plurality of images of said first array;

c. means for aligning a first portion of the first image of said first array with a second portion of the second image of said first array and so forth throughout said plurality of images of said first array to form an image of a second array consisting of said plurality of characters rearranged into a second number of lines; and

d. means for placing said image of said second array of characters on a second medium.

2. Apparatus as recited in claim 1 wherein said first array comprises said characters arranged in a plurality of lines and said second array comprises said same characters rearranged into a single line.

3. Apparatus as recited in claim 2 wherein said optical means includes means for optically multiplying said first array to produce a number of images of said first array equal to the number of lines in said first array, and wherein said aligning means includes means for displacing said plurality of images relative to each other to align the first line of characters from the first image of said first array with the second line of characters from the second image of said first array and so forth throughout said plurality of images of said first array to fonn said single line of said characters.

4. Apparatus as recited in claim 1 wherein said optical means comprises a first plurality of reflecting means upon which said first array is imaged and a second plurality of reflecting means for receiving said images reflected ofi said first plurality of reflecting means and for placing said plurality of images in alignment.

5. Apparatus as recited in claim 4 wherein said aligning means comprises means for mounting said plurality of first and second reflecting means at an angle relative to said first array.

6. Apparatus as recited in claim 5 wherein said first and second reflecting means comprise a plurality of parallel mirror pairs, said first array being imaged on the first mirror of each of said mirror pairs and reflected therefrom onto the second mirror of each of said mirror pairs for placing said plurality of images in alignment.

7. Apparatus as recited in claim 1 and further including masking means for placing only said second array on said second medium and for blocking all remaining portions of each of said plurality of images of said first array from said second medium.

Claims

1. Apparatus comprising: a. a first medium having a first character array thereon, said first character array consisting of a plurality of substantially stationary characters arranged in a first number of lines; b. optical means for optically multIplying said first character array to produce a plurality of images of said first array; c. means for aligning a first portion of the first image of said first array with a second portion of the second image of said first array and so forth throughout said plurality of images of said first array to form an image of a second array consisting of said plurality of characters rearranged into a second number of lines; and d. means for placing said image of said second array of characters on a second medium.

3. Apparatus as recited in claim 2 wherein said optical means includes means for optically multiplying said first array to produce a number of images of said first array equal to the number of lines in said first array, and wherein said aligning means includes means for displacing said plurality of images relative to each other to align the first line of characters from the first image of said first array with the second line of characters from the second image of said first array and so forth throughout said plurality of images of said first array to form said single line of said characters.

4. Apparatus as recited in claim 1 wherein said optical means comprises a first plurality of reflecting means upon which said first array is imaged and a second plurality of reflecting means for receiving said images reflected off said first plurality of reflecting means and for placing said plurality of images in alignment.