US2146937A - Multiplex scanning system - Google Patents

Description

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A, J CAWLEY 2,146337 MULT I FLEX SCANNING SYSTEM Filed May 29, 1931 2 Sheets-Sheet 1 A. .1. CAWLEY MULTIPLEX SCANNING SYSTEM Filed May 29, 1951 Patented at. iese e I are as 8 @lairns.

An important object of the invention is what I term multiplex scanning, i. e., the number of lines that are ordinarily scanned by a scanning element, such as a Nipkow disk are increased by any desired multiple. This multiplication of scan-- ning lines is accomplished by optical means. Several such means for accomplishing this result are described and illustrated using either refraction or reflection. Any of those means are placed in the path or" an ordinary scanning light beam in such manner that it is made to change its direction at one or more points so that it describes several parallel lines instead of a single line. An image results that is made up of several times the number of lines than an ordinary image.

The reflex optical lever is used in some of the modifications as an adjunct to the multiplex scanning. The scanning light beam is speeded up before it is acted upon by the multiplex elements.

Means are also disclosed by which the scanning beam is refracted or diverted laterally in order that it may describe a longer path before this path is broken up into several shorter parallel paths, thus giving desired symmetry to the resultant image which might otherwise be too narrow.

A simple modification is also described in which the ordinary projection apparatus is used to increase the path of the scanning light beam before it is caused to describe its series of parallel paths.

A reflex optical lever arrangement is disclosed also which employs a two cylinder single rotating element, one of the cylinders bearing a circle of spherical lenses and the other bearing a series of helically arranged cylindrical lenses. The light beam, whose speed of scanning has been increased is then caused to impinge upon a series of totally reflecting prisms which are slightly displaced in more than one plane with respect to each other.

A modification is also described in which a standard scanning element, such as a Nipkow disk is used in such manner that several images are projected in superposition resulting in a composite image which is made up of several images each of which is scanned in a different direction. This multidirectional scanning results in great detail if the image.

The multiplex scanning principle is also applied to such a multiplex scanning arrangement with the result that the number of lines in each image is increased, resulting in further detail.

- The reflex optical lever principle may also be applied to this modification whereby the scanning speed of the light beam is sped up before it encounters the multiplex scanning means, whether consisting of lenses or prisms, which give the desirable result of increased number of scanning lines.

By the means disclosed in this specification it is possible to produce a composite image made up of, for instance, four separate images, each of which is scanned in a different direction, and each of these images may be made up of four times the number of lines as the disk used would produce if ordinary scanning were used on a single image.

This application is a continuation-impart application of my applications Serial Number 391,541, filed September 10, 1929, for Scanning process; Serial Number 468,117, filed July 15, 1930, for Television apparatus; Serial Number 473,660, filed August '7, 1930, for Scanning apparatus covering a special reflex scanning principle, and Serial Number 513,373, filed February 4, 1931, for Reflex television system, issued as Patent No. 1,956,482, March 13, 1934.

I attain the above objects by the apparatus illustrated in the accompanying drawings, in which like reference characters have similar means, and in which, I

Figure 1 is an elevation view of an arrangement for producing multiplex scanning with or without the optical reflex lever principle.

Figure 2 is a plan view of the means used in Figure 1 for producing the multiplex scanning.

Figure 3 is a plan View of another modification for producing multiplex scanning.

Figure 4 is an elevational view of a modification for producing both multiplex scanning and a reflex optical lever effect, the scanning element being shown in cross section.

Figure 5 is an elevational view of a means of producing multidirectional scanning from a single rotating scanning medium and also illustrating the application of the reflex optical lever thereto.

Figure 6 is an elevational view of still another apparatus for accomplishing multidirectional and multiplex scanning together with the application of the reflex optical lever thereto.

Figure 1 is a representation of a receiving apparatus in which an image is formed upon the screen S. A glow lamp, such as one of neon, is illustrated at l. The light from this lamp passes through the series of spirally arranged spherical lenses 2, which forms a series of moving light beams. Those beams cooperate with'the prisms 3, 1 and 5, as described in the above mentioned application for reflex scanning, in order to increase the speed of traversal, or scanning, of those beams. The lenses are here illustrated as being spirally arranged on an ordinary Nipkow disk D. The final result of the passage of the light through the prisms 3, etc., is a series of rapidly, moving beams each describing a path such as represented by the arrow 8. Suitable optical means is interposed in this path, which acts to divide the beam into several portions whose directions are modified both in the horizontal and vertical planes in such manner as to cause the beam to describe successively a plurality 01 parallel lines. In Figure l, I have illustrated an optical means consisting of three cylindrical lenses A, B and C having their axes placed horizontally. It will be noticed that the line representing the path of the beam as it comes from the prism 5 and a corresponding spherical lens, is broken up into three parts a, b and c by the lenses A, B and 0. Lens A is placed vertically, but its left edge is nearer the screen than the right. It will, therefore, direct its portion of the line to the right and maintain it at its origi nal level. Lens B is placed parallel to the screen S, but its top edge is nearer the screen than the bottom edge. It produces the line 2) directly under the line a, which was scanned by the lens A. Similarly, lens C has its top edge still nearer the screen than has lens B. Also, its right edge is nearer the screen than its left. It therefore, scans the line 0 which is under line b. There fore, when the original beam describes a line such as abc on the three lenses A, B and C, this line is modified so as to produce three parallel lines a, b and c on the screen. Thus a number of lines will be scanned that is equal to three times the number of holes or lenses on the scanning medium, such as disk D. This is an immense advantage. The optical lever, represented by the prisms 3, 4 and 5 cooperating with the lenses increases the rate of movement of the light beam emanating from the neon lamp i. This rate of movement has been amplified three-fold by the prisms illustrated in this figure. The three lenses A, B, and C act to cause this beam of light to describe three parallel paths instead of the single path.

The three cylindrical lenses A, B and C are illustrated in Figure 2. This is a plan view. It

will be noted that the lens A has its left edge turned toward the screen. B is parallel to the screen, but has its upper edge bent forward towards the screen. C is bent forward still more than B and has its right edge nearer the screen than the left. A permits the light to pass at the same level as the original beam, but turns the beam inward to draw the first line a. B does not alter the direction of the beam as regards right and left, but lowers it, so that it takes its place under a to draw the line b. 0 acts to turn the beam inward and downward in order to draw the line 0.

Figure 3 illustrates an embodiment of the invention which does not make use of the optic lever principle. Light passes from the glow lamp I through lens such as 2 carried on Nipkow disk D. As 2 moves to the right, a beam of light sweeps over the screen S, and describes a line thereon which is many times longer than the distance traversed by the lens 2. A concave cylindrical lens E is interposed in the path of the light beams in order to increase the distance which those beams travel. The object is to procure an image area on the screen S that is several times as wide as it is high. It is then only necessary to cause each line in this image area tc-be broken up into several lines of correspondof the beams in their respective areas.

ingly less length than the original line. In the figure the original beam describes the long path ac, also indicated by the arrow 6. When each lens 2 in disk D describes their individual paths or lines, the result is an area covered by those paths which is (in this illustration) three times as wide as it is high. But there is interposed in this area the refracting elements represented by the prisms l and 9, which modify the course The result is that prism "i acts by its refractive powers to bend its portion of the light inward and up- "ward; --The'p'rism is shown tilted back away from the screen S, and this acts to raise the beam, therefore line a is drawn on the screen. 8 is merely an ordinary piece of plate glass, which is perfectly symmetrical. It may be omitted. Therefore, it permits the light to go forward Without any modification. It therefore, scans line b. and since it is tilted towards the screen, as shown, it also acts to lower the beam. The result is that it scans line 0. It will thus be seen that as the lens 2 moves to the right, line a is first scanned.

Then the light beam instantly shifts back and sufficiently when the paths of the beams are broken up into a plurality of paths to produce a square or otherwise symmetrical image. A projecting lens or projecting optical element is not shown in this figure, but such may be used. If the distance between the lenses 2 on the disk D is one half inch, if the arrow 5 representing the path of the scanning beam before being broken up into a plurality of beams, is six feet, it is evident that this beam moves this six feet in the same time that the lens 2 moves one-half inch. Projection, therefore affords an optic lever effeet, and this principle is used in many scientific recording instruments. The tilting of the refracting elements is greatly exaggerated for illustration purposes. This is simply a matter of adjustment in the apparatus. No projection means has been shown with Figures 3 or 6, the projecting effect of the spherical lenses being relied on. Standard projecting means may readily be added.

Another modification of the invention is shown in Figure t. Here a disk D is provided with two cylindrical portions F and H. The disk is mounted on the shaft of motor M. The glow lamp, or photoelectric element, is shown at l. A suitable number of prisms 3, 4, etc., is provided to give the desired optical lever effect. Those prisms cooperate with the spherical lenses 2 carried. on cylinder H. The resultant beam is moved laterally (according to the well known principles of scanning) by the helically arranged cylindrical lens G. As the cylinder is revolved, the beam of light would move from left t right in the figure and up and down on the screen S.

The light beam after leaving the lens G meets the three totally reflecting prisms d, c and I, which may be replaced by any reflecting means, such as three mirrors. The beam of light is thus turned to the right and impinged upon the screen S. Prism e is placed perfectly vertical Prism Q bends the light beam inward in the figure, prism d is as shown bent away from the screen, and it therefore scans line a. Prism c scans line b. Prism 1 is turned toward the screen, as shown and therefore scans line lower than the others. Prism 2 is placed perfectly parallel to the screen when the screen is viewed from above, while prisms d and f are turned inwardly at their outermost edges in order that all three lines may be placed directly parallel to each other. However, it is a very simple matte to arrange the prisms or mirrors in order to cause them to project the light beam which impinges upon them in the maner illustrated on the screen S of Figure 6.

The disk D in Figure 5 is an ordinary Nipkow disk in which the lenses 2 are arranged in a spiral in the usual manner. It will be noticed that four scanning apertures are provided at four points on the disk D which are located forty five degrees apart. Projection means N are provided at each of those four points, as described in the above mentioned application of mine. All four of those projection means project their individual images superposed upon the screen S. The projection means shown at the top of the disk projects its image upon the screen S and scans it in a horizontal direction as indicated by the arrow 9. scans its image at an angle to this, as indicated by the arrow h. The next projection means N scans its image in a vertical direction, as indicated by the arrow 2', while the last projection means scans its image in a direction indicated by the arrow There are thus produced four images scanned in different directions which are combined by superprojection or superposition to form a composite image of great detail. All four photoelectric elements i may be actuated by four distinct sets of wave trains. In another modification, they may be all actuated by the same wave train, but in that case, the number of holes or lense 2 should be reduced to one-fourth of the usual number, In this event, each projection means will be actuated in its turn, and only one will be in action at any time. This is due to the fact that the reduced number of lenses only permit the light of one projection means to pass at any time. In this modification, however, the number of lines in each image is one-fourth that of the number of lenses 2 in the disk D. The scanning speed may be increased by adding the optical lever principle. Therefore, each of the projecting means has coacting with it the prisms 3, l, 5 and L, which increase the speed of the light beam coming from the glow lamp l.

Several modifications are possible with Figure 5. For instance, a disk having the full number of cylindrical lenses 2, four photoelectric elements 5 and four projecting means N located at four different points of the disk and projecting four different images scanned in different directions and superposed to produce a composite image without the use of the optical lever principie. With this arrangement it is possible to supply each photoelectric element with its own individual current supply giving each a different set of wave trains. Or, all photoelectric elements may be supplied with the same source of image-varied current, thus keeping down the number of wave trains used.

If each photoelectric element is supplied individually a composite image will be formed made up of four images, each of which will have the same number of lines as there are spherical lenses on the disk D.

The next projection means However, if all are supplied by the same wave channel or current source, then it is necessary to reduce the number of lenses on the disk to one-quarter, i. e., every second, third and fourth lense is out out. They are now four times as far apart as before, with the result that only one lens will be in an image field at any one time. The different photoelectric elements I are therefore, alternately exposed for projection of its light upon the screen. There will be produced, therefore, four superposed images each having one quarter the number of lines as before.

The reflex optical lever principle may be added to either of the above modifications, and is illustrated in Figure 5. It is necessary to move the photoelectric elements i away from the projecting means N to allow for the prisms of the lever. The photoelectric element 3 has its intensity varied in-accordance with the image being transmitted. Its image-varied light is formed into moving beams by the lenses 2. Those beams enter the prism 3 and are reflected back through a neighboring lens into prism l, when it is again reflected back through a neighboring lens. Its speed has thus been amplified and it now sweeps over the screen S to describe its line, such as g. In a similar manner, the other elements at each of the other three points on the disk act to scan lines it, i and a'. or course, the four lines on screen in the illustration serve to illustrate the equivalent of scanning one line of the images. There is, of course a constant shifting of the lines in accordance with the images being produced. It is to be noted that the lines are scanned in the difierent image fields in an intercalated manner, i. e., a line is scanned in each image field alternately instead of scanning all of one image first and then a second, and so on.

If aperson, for any reason could not afford to have a photoelectric element and projecting means at each of the points on the disk described, they may all be left out except one, as a sufficiently satisfactory picture will result. This is due to the fact that each image is scanned as completely as an image is scanned by other means. If he could only afford two elements at two points on the screen, these may be added. It is very important to note that if synchronism is attained for one of the photoelectric elements l and its projecting means N, then all images are in synchronism. It is well known that intercalated scanning of itself gives greater detail, and it is also well known that scanning in different directions also of itself gives greater detail. Both are employed in this invention.

It is also very important to call attention to the fact that the other half or the disk may also be provided with projecting scanning means, andcombined to produce an image that may be placed side by side with that illustrated on the screen. We thus have an oblong image (similar to the view of a stage or the view obtained in field glasses) iving enormous detail. Or, the disk may be provided throughout its entire periphery with scanning-projecting means, say a total of eight. Each two located 90 degrees apart may be superposedly projected to form a composite image, resulting in four distinct images side by side in the form of a square.

Figure 6 shows a modification embodying the optical lever and multiplex scanning principles. A helix of lenses 2 is arranged on the cylinder C. When used as a receiving apparatus, the glow lamp I transmits its light through the lenses 2 and the series of prisms 3 and 4, in the all. gra es? manner described in connection with the optical lever in my application covering reflex scanning. The final speed-amplified beam traverses the prisms O and P similar to the manner of operation described in connection with Figure 4. This beam is reflected by the prisms O and P in the manner already described, with the result that the single path described by the image varied light beam emanating from the lens 2 is broken up into two parallel paths, thus two lines m and n are scanned on the screen S where only one would be scanned if the prisms O and P were not used. In a similar manner, the prisms The result t and u describe the lines It and Z. is that two images are projected in superposition upon the screen S, which are scanned in directions which are at right angles to each other, and those two images are combined to form a composite image which ha much greater detail than that possessed by either image alone. If the photoelectric elements, such as glow lamp are each supplied by a distinct wave train and source of illumination, then two images will be superposed that will be scanned in directions at right angles to each other, and each of those images will contain twice as many lines as there are lenses 2. Or twice as many lines as would ordinarily be scanned by the lens cylinder if the prisms t, u, and O, P were not used. This is due to the fact that each ordinarily scanned line is divided into two parallel lines, such as it and Z. This is the modification illustrated in Figure 6, where the number of lenses 2 is unreduced. The reflex optical lever is also shown in this modification. However, it may be omitted, and the lenses 2 and prisms t, u, 0 and P used without it. Instead of the prisms t, u, 0 and P, mirrors may be used. Of course, when the reflex optical lever is not used, the photoelectric element mustbe moved directly opposite the point on the cylinder C where the image is projected upon the screen S.

If it is desired to supply the same wave train and source of power to both glow lamps simultaneously, and thus keep down the width of the transmission channel in the ether, then in order to cause them to project their images alternately, the number of lenses 2 will be reduced one half. In other words, every second lens will be eliminated from the cylinder C, and this will mean that the lenses are spaced twice as far apart as before. With this arrangement, when one lens is in the path of the light coming from the glow lamp l at the top of the figure, there will be no lens in the path of the light from the glow lamp l at the right of the figure. The result is that two images will be superposed, each of which will be scanned in directions at right angles to each other and each image will contain twice as many lines as there are now lenses Lion the cylinder C, or stat-- ing it in other words, each image will contain a number of lines equal to the number of lenses originally on the disk.

It is to be noted that the difference between the elements A, B and C of Figures 1 and 2, and of 'l, 8 and 9 of Figure 3, d,c and f of Figure 4 and O, P, t, u of Figure 6 is greatly exaggerated in the illustrations. This is to bring out clearly their difference of arrangement. actual dif ferences are quite small. This is particularly true as regards the tilting of the elements nec essary to bring the light beam in contact with the screen below the line last scanned. The various elements maybe cut to fit closely together when they may be cemented by such substances as Canada balsam forming a single unit. They are shown as separate as possible in order to bring out their horizontal and vertical inclination. The composite image of Figure 5 will be a literal net-work of scanning lines running in different directions. r

Having described my invention, I claim as new and desire to secure by Letters Patent: ,1. A television apparatus consisting of an electro-optical element, a moving element, a plurality oi light modifying elements carried on said moving elementand producing a series of mov- 'ing"""lig'ht beams from said electro-optical element, optical means including a plurality of plane inclined reflecting surfaces, for increasing the length or" the paths described by said beams, a plurality of stationary differently inclined and difierentiy turned optical elements in the path of said bean-is causing each of said beams to describe a plurality of parallel paths and a screen upon which said paths are described to produce a visible image.

2. A television apparatus consisting of a source of image varied light, a rotating element provided with two cylindrical portions, a plurality of lenses arranged in a circle carried on one of said cylindrical portions and producing a series of image-varied light beams moving in the same plane, a helically arranged cylindrical lens carried on the other of said cylindrical portions producing a lateral shifting of said light beams, a series of stationary diiierently inclined and differently turned reflecting elements acting to cause each of said beams to describe a plurality of parallel paths and a screen upon which said beams describe said paths in order to produce a visible image.

3. A television apparatus consisting of a source of image-varied light, a rotating element pro- 1 vided with two cylindrical portions, a plurality of circularly arranged spherical lenses carried on one of said cylindrical portions and producing a series of image varied light beams moving in one plane, a plurality of prisms coacting with said beams and said lenses to augment the speed of movement of said beams, helically arranged cylindrical lenses on the other of said cylindrical portions to produce a lateral shifting of said beams, a series of stationary differently inclined and differently turned reflecting elements acting to cause each of said beams to describe a plurality of parallel paths and a screen upon which said beams describe said paths in order to produce a visible image having a large number of scanning lines.

4. A television apparatus consisting of a rotating element, a plurality of image varied light sources adjacent different points on said rotating element, a series of light mochi'ying means carried on said rotating element acting to produce a plurality of series of moving image-varied light beams from each of said light sources, stationary differently inclined and differently turned optical means placed in the path of each of said beams produced at said points to cause said beams to describe a plurality of parallel paths producing an image of increased number of lines at each of said points, the paths of said light modifying elements being at different an les to the axis of said light sources causing each of said images to be scanned in difierent directions, means for superposing said images and a screen upon which said images are received.

5. A television apparatus consisting of a roamass? S tating element, a plurality of image-varied light sources adjacent difierent points on said rotating element, a series of light modifying means carried on said rotating element acting to produce a plurality of series of moving image-varied light beams from each of said light sources, a plurality of groups of reflecting prisms constituting a reflex optical lever coacting with said light modifying means at said different points in order to increase the speed of movement of said beams, stationary differently inclined and differently turned optical means placed in the path of each of said beams produced at said points to cause each of said beams to describe a plurality of parallel paths producing an image of increased number of lines at each of said points, each of said images being thus scanned in different directions, means for superposing said images and a screen upon which said images are received.

6. A process of scanning consisting of producing a plurality of series of successive, image-varied light beams in an image area, causing each of said beams to describe a definite path in said image area, the direction of the path described by each series of beams being at an angle to each other, the paths of said beams being parallel, increasing the speed of movement of each of said beams in order to increase the length of each of said paths, refracting said beams in two directions at right angles to each other in order to periodically vary the direction of each of said beams while each of said beams describes its lengthened path in order that each of said lengthened paths shall be broken up into a plurality of parallel paths so that the number of scanned lines ordinarily described in said image area shall be multiplied and a composite image scanned in difierent directions formed therein.

'7. A scanning apparatus consisting of means for forming and moving a series of light beams to describe parallel paths, means including a plurality of plane inclined reflecting surfaces for increasing the length of said paths, differently inclined and differently turned stationary optical means in cooperative relation with said beams along said paths for deflecting said beams hori zontally and vertically in order to cause said lengthened paths to be converted into a series of parallel sub-paths and a screen upon which said paths are described to form an image consisting of a plurality of paths.

8. A television receiving apparatus consisting of a plurality of electro-optical elements disposed at cliiTerent points each projecting a beam of light in scanning relation upon an image area, a rotatable scanning element in cooperative relation with each of said electro-optical elements to produce scanning movements of said beams in different directions, means in cooperative relation with said electro-optical elements and said scanning element for increasing the speed of 1 movement of each of said beams, means for converting the paths of said beams into a multiplicity of parallel paths and a screen upon which said beams impinge toproduce a composite image consisting of a plurality of superposed images.

ALOYSI'US J. CAWLEY.

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