US1787921A - Television apparatus - Google Patents

Description

Jan 6, 1931. A. H; wATsoN 1,737,921`

TELEVISION APPARATUS Filed April 22. 1929 lllnIllllllllll/Ilffl C' i! l Y Z0 /r A 1 2a f7@ y 15 and the 40 scanning `mechanism Patented Jan. 6, 1931 ARTHUR H. "WATSON, F CHICAGO, ILLINOIS TELEVISION. APPARATUS animation nica April 22,

This invention relates to improvements in television apparatus and particularly to the scanning mechanism forming. the essential part ofthe apparatus.

The present invention is an improvement over that type of apparatus described and illustrated in my co-pending application for patent, Serial No. 345,005, filed March 7, 1929.

An object of the invention is to provide an improved television apparatus.

In the transmission and reception of television pictures today two distinct types of pictures are formed, one consisting o a plurality of substantially straight parallel lines other consisting of a plurality of curved parallel lines. This condition is brought about bythe employment of apparatus in the first instance including a drum scanning mechanism,-that is, a rotating drum, from-which beams of light pass subl stantially radially to scan the object at the transmitting end and, in the case of the re- 'ceivng' apparatus, to traverse a screen. L Such an arrangement of apparatus produces what is known as a straight line picture.

. Other types of apparatus incor orate what isknown as the circularscanning iscthrough or from which rays ass or are reflected in a direction substantially parallel with the axis of rotation in both the transmittin and receiving apparatus. The result or: this arrangement is the forming of what is known as a curved line picture.

I shall not describe in detail the construc- 3ation or operation of thecdrum type scanner or *the* "disci type Scanner, as this mechanism is well knownin-theart. L l

.The` principal object offmy resentinvention is to incorporate in television apparatus formin a part of the apparatus which is capableo producing both straight line and curved hne pictures at will. Another object is to provide televislon apparatus wherein the change from straight line to curved line pictures or vice versa may be accomplished by the mere shifting of position of the scanning mechanism. Another object is to provide .television apparatus which is extremely compact and 5 simple in construction.

' housing A, cluding the drum B `1929. Serial No. 356,944.

. Other objects and advantages willbe hereinafter set forthin the following description and appended claims. f'

Apparatus embodying my invention is illustrated in the accompanying drawings forming a part of this application wherein: Fig. 1 is a vertical sectional view through the apparatus;

Fig. 2 is a front elevation of the apparatus illustrated in Fig. 1;

Fig. 3 is similar to Fig. 1 illustrating the f scanning mechanism in its shifted position to produce curved line pictures;

Fig. 4 is a schematic illustration showing the scanning mechanism adjusted for a straight line picture;

Fig. .5 is a schematic illustration similar to Fig. 1 but showing the scanning mechanism set for a curved line picture; and

Fig. 6 is a diagrammatic view illustrating the electrical circuit for controlling the motor and glow lamp.

In general, my improved television apparatus comprises a housing A, a scanning drum B, the construction of which has been particularly set forth in ny aforementionedpending application, a motor C for driving the drum, a glow lamp D instantaneously responsive to the output current from` a radio receiver arranged so that its light may be reilected from the drum B upon a translucent screenE. disposed at the front wall of the the entire scanning mechanism ing and motor C being shiftable to either o f the positions illustrated in Figs. 1 and 3 at will.

The housing A may be constructed of wood or metal.' and made substantially light-proof with itstop wall 10 forming a cover inged at 11` so as to facilitate access to the interior of the housing. The glow lamp D is mounted in a tube 12 which projects fthrough an annular ring 13 having a rack and pinion adjustably `associated therewith for moving the lamp D along its optical axis toward or away from the drum B. This structure permits th'e focusing of the light spot reflected from the Idrum upon the screen E. The lamp D may be any type of'lamp which is capa le of assumin brilliancy and falling back to total dar esi in intervals of time not longer than onetwenty thousandth of a second. For this purpose neon gas glow lamps of the crater type have been widely used. The light produced is highly concentrated so that it may be reproduced on the screen E in substantially the same size and shape.

The scanning drum B is rotatably mounted upon a frame 15 and geared through a speed reduction mechanism enclosed in housing 16 to the motor C. In the present embodiment of the invention I contemplate using a variable speed motor, the speed of which may be controlled by the operator by rheostat 17, the current for which may be turned on and ofl' by manipulation of a switch 18.

Both the motor C and the frame 15 upon which the scanning drum is mounted are carried upon a plate 19 which is secured by bolts and wing nuts 20 to either the bottom wall 21 or the rear wall 22 of the housing A, depending upon the nature of the picture required, i. e., straight line or curved line pictures.

The drum B has a plurality of separate concave reflectors 30 mounted thereupon, the number of which determines the number of lines in the picture, each of which is so adjusted as to cause light reected from the lamp D to traverse the screen E in a succession of substantially parallel lines close enough to one another to illuminate the entire screen when the disc is rotated at a speed of substantially 900` R. P. M. This phenomena is caused by the persistency of vision and is wellknown in television practice.

The concave reflectors 30 comprise optical elements which cause a focusing of the light from the lamp D to a spot such as represented at 32 upon the screen which is virtually an image of the visibly illuminated part of the amp.

The lamp D is controlled in general by a variable resistance 35 in series therewith so that the operator may increase or decrease the general illumination of the picture.

In operation the output terminals of a radio receiver are connected to the input terminals 36 (see Fig. 6) of the lamp D and the alternating current so conducted to the lamp changes in proportion to the signal strength of the broadcast picture and causes the lamp D to rise and fall in illumination, which constant change in intensity of illumination is perceived upon the screen E asthe drum B revolves at substantially 900 R. P. M. or at such speed as is prescribed by the broadcasting station. It should be noted here that the speed and relative position of the drum B must exactly coincide with the similar rotat- ,ing part of the scanning mechanism at the broadcast station. Hence the rheostat 17.

Assuming that the apparatus is assembled as shown in Fig. 1, and with reference to Fig. 4, it will be seen that the light reflected from lamp D will be reflected from the reflectors 30 along Substantially radial paths with respect to the axis of the drum,-hence the line drawn by the moving spot 32 will be a straight line and as the drum continues to revolve a plurality of straight lines will be so formed to comprise a complete picture, the persistency of vision operating to maintain the picture wholly upon the screen for one revolution of the drum. Upon the next revolution a new picture will be formed.

It is important that the scanning apparatus embodying my invention shall be constructed with the concave reflectors 30 set at substantially 45 degrees from the axis of rotation as otherwise a shift from straight line to curved line pictures would be difficult to accomplish.

Let us assume now that it is desirous to produce a curve line picture because the broadcasting station in operation at this time is broadcasting with apparatus including a disc type scanner. The operator then will shift the plate 19 bearing the motor and scanning drum to the position shown in Fig. 3 and schematically in Fig. 5, at the same time throwing the reversing switch 40 on motor C. The result of this change in assembly will cause light reflected from the lamp D to be projected away from the reflectors 30 on the rum along axes which are substantially concentric with the axis of rotation and a curved line will be produced as the spot 32 traverses screen E.

What I claim is new and desire to secure by Letters Patent of the United States is:

l. Television apparatus comprising a source of concentrating light, a screen, a rotatable drum and a plurality of focusing re'- flectors, said reflectors being so arranged as to reflect and focus said concentrated light upon the screen along axes substantially radial to the axis of the drum when the axis of the direct light beams from said light are perpendicular to the vplane of rotation of the drum, whereby a line described by the focused light upon the screen when said drum is rotated is substantially straight.

2. Television apparatus comprising a source of concentrated light, a screen, a rotatable drum and a plurality of focusing reflectors carried on said drum, said reflectors being arranged circumferentially about the drum and having their reflecting surfaces inclined at substantially 45 degrees from the axes of the drum, said light source having its optical axis perpendicular to an axis perpendicularly intersecting the center of said screen, both ofsaid axes intersecting in the lane of said reflectors, each of said reflectors ginning with Vone certain reflector having its angle of inclination slightly less than the next adjacent and succeedmg reflector thereby causing the successively described lines 'upon the screen to lie one beneath the other.

mamar 3. In a television apparatus, a rotatable member, a plurality of reflectinig surfaces on said member angularly disposed with respect to the axis of rotation thereof, a fixed source of light, a fixed viewing screen and means permitting the shifting of the axis of rotation of said rotatable member to vary the path of light from said light source as it is relected from said surfaces to said screen to scan in straight or curved lines at will.

4. 1n a television apparatus, a. rotatable member, a plurality of reflecting surfaces on said member angularly disposed` with respect to the axis of rotation thereof, a source of 1i ht, a viewing screen and means for permitting relative movement between said li ht source and the axis of said rotatable mem r to Vary the path of light from said light source as it is reiected from said surfaces to said screen to scan in straight or curved lines at will.

In witness whereof, l hereunto subscribe my name this 19 day of April, 1929.

. ARTHUR H. WATSON.

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