US 1848888 A
Description (OCR text may contain errors)
March 8, 1932. J KENDALL 1,848,888
TRANSMISSION AND RECEPTION OF PICTURES Filed Aug. 20 1929 Inventor-t J ame s M.Kendau,
" 20 the receiving station.
Patented Mar. 8, 1932 p uNiT IEo 'SETATES PATE T}- JAMES 1m KENDALL, or SCHENECTADY, new: You, nssienoit'ro COMPANY, A oonrona'rronornnw prom; a 1
, rmsmssron AND-RECEPTION or rro'runns Application filed August 20,1929. Seria111q'o."387,1 76.
My invention relates to the transmission and reception of pictures and the like, and has for-its principal object the provision of an improved apparatus and method of operaj5 tin whereby pictures may .be transmitted and received without flicker and with a high degree of efiiciency in the utilization of the light provided for illuminating the screen upon which the picture is produced.
In the past various types of picture transmitting apparatus including either a radio transmitter andreceiver or a transmitter and receiver connected together by electrical conductors have been provided; -Many of 3 1 .these apparatus involved the use of means for producing a light dependent on the shade .of the picture to be transmitted and means for converting such light -intoelectrical-im- .pulses whichmust be reconverted to light at Such apparatus has not proved altogether satisfactory in practical use for the reason that they are more or less complicated. in structure and involve variable illuminationand-visibility of the 25 screen onwhich the, picture is reproduced.
I In accordance withmy invention these difficulties are avoided by the provision of an improved light control screen which is continuously. illuminated and involves a plurality of small movable sections or shutters which are readily controlled in accordance with the shade ofthe corresponding areas of the picture to be transmitted.
My invention will be better understood from the following description when con sideredin connection with the accompanying drawings and ,its scope will be' pointed out in the appended claims. r
Referring .to the drawings, Fig. 1 illustrates apicture receiving apparatus wherein my invention has been embodied; Figs. 2 and 8 show details oi a light control screen which forms a part of the apparatus illustrated by in the electrical connections by which the operation of the lightcontrol screen is controlled.
The apparatus illustrated by Fig. 1 includes a light control screen 10 which is interposed between a light source 11 and the tween these members;
- readily understood if it be assumed thateach 1 picture receiving member '12 and iscontrolled in accordance-"with the signals received through a radio receiver 131 Suitablelenses 14 and 15 are interposed between" the light source 11 and the screen 10 and between the screen 10 and the picture'receiving member 12. As will. hereinafter-appear more fully, the operation of the light control screen 10 is controlledby means of a contact device 16 which may be driven a motor 17 Ca- 0 'paoitance elements 18 Fare connected to the receiver '13 in shunt with the rnovable and fined elements of the screen 10 for.=intensifying the efiect-o't the capacitive Tcoupling'be- 1 The screen 10 comprises a plurality of movable" elements 19 which are pivoted at' 20 and form one plate of an electrical condenser, the otherplates of each condenser being one ot-the members 21. The condenser plates 21 aremounted on and elctric ally insulated from the members 22 whichare supported by endz'supports '23. iTheTcondenser plates 21 are electrically insulated from the rest-of the light control screen and are connected to different segments of the contact device. 16.
. Referring.morerparticularly to Figf":4c,:it
will be observed that the condensers-18 are arranged to be connected to the radio receiver 13 through the contact device 16, each conso denser '18) being connected "to one segment of the contact device in parallel with a condenser formed by 'one pair of the plates 19 and'21. Any suitable means such as' a motor 17 maybe provided for driving the:contact device in synchronismwith the picture scanningand transmitting apparatus.
- y The small-condenser plates 19;may be made of thin aluminum, gold leat' or the like, and are ,so arranged that they:assume;a position 590 dependent on thecharge imparted to them through the particular contact device segments with'which they; are connected. Fig. 2; and Fig. 1 illustrates certain details .The operation of the apparatus-:will-be of the small movable condenser plates 19 represen'tsa unit area of the picture and'each row of the plates 19 represents a :row or;line
ofunit orelementary picture areas. ;;Under these conditions the condenserplates 19 are 1-100 successively connected to the radio receiver 13 through the contact device 16 and successively receive electrical charges which are dependent upon the shade of that part of the picture to which the condenser plate corrsponds. Due to these charges the plates 19 are moved more or less toward the cooperating condenser plates 21. Thus if the condenser plate corresponds to a white part of the picture the charge it receives is comparatively large. It is moved comparatively close to its cooperating plate 21 and admits a comparatively large amount of light from the light source 11 to the picture receiving member 12. If the plate 19 corresponds to a darker part of the picture however, it is moved through a smaller angle and permits a reduced amount of light to be projected on the member 12. the voltage applied through the radio receiver 13 being at each instant dependent on the shade of the particular elemental are being scanned at that time.
It will of course be understood that the brush of the contact maker 16 is rotated synchronously with the signals received. As the brush passes each segment. it charges the corresponding condenser 19 21 almost instantly to a potential dependent upon the signal received. The condenser holds its charge and remains at practically the same potential until the brush passes over the distributive segment again. If there is no motion in the part of the picture corresponding to the movable plate of the condenser, the movable plate thus remains stationary and the light projected on the part of the receiving member which it controls is unchanged. If the part of the picture corresponding to the particular plate 19 has moved, the potential applied to the condenser 19-21 is changed and more or less light is projected on the part of the receiving member which it controls, the amount of light of course depending on whether the charge has increased or decreased.
As will be readily understood by those skilled in the art, the use of the improved light controlled screen is advantageous in that it permits the use of a very intense source of illumination and may be utilized to produce clearly defined pictures of any desired size. The small shutters or condenser plates '19 are not required to respond faster than in the order of 1/24. of a second. and of course do not have to move that often when the corresponding part of the picture remains however, that the invention is susceptible of being modified to meet the different conditions encountered in its use and I therefore aim to cover by the appended claims all modifications within the true spirit and scope of my invention.
\Vhat I claim asnew and desire to secure by Letters Patent of the United States is:
1. A picture producing apparatus comprising a light control screen including aplu- *ality of electro-staticall controlled pivotaly mounted shutters, means for projecting ight through said screen, and means for ausing said shutters to assume positions of light interception dependent on the shade of the picture to be produced.
2. A picture producing apparatus comprising a light control screen provided with a plurality of el ctro-st-atically controlled pivotally mounted shutters, a picture receiving member, means for causing said shutters to assume positions dependent on the shading of the picture to be produced, and means for projecting light through said screen upon said picture receiving member.
3. A picture producing apparatus including a light control screen provided with a plurality of electro-statically controlled pivotally mounted shutters, a picture receiving member, a source of illumination arranged to project light through said light control. screen upon said picture receiving member, a device for receiving signals dependent on the shading of the picture to be produced, and a contact device arranged to cause said shutters to be operated in accordance with said signals.
4. Picture producing apparatus including screen comprising a plurality of pivotally mounted condenser plates forming shutters arranged to variably intercept the passage of light through the screen, and means for ca using said plates to assume positions dependent upon. the shading of the picture to be produced.
5. Picture producing apparatus including a picture receiving member, a source of light, a screen therebetween comprising a plurality of pivotally mounted condenser plates form- .ing shutters arranged to variably intercept the passage of light through the screen, and means for charging said plates to cause them to assume posit-ions dependent upon the shading of the picture to be produced.
In witness whereof, I have hereunto set my hand this 19th day of August. 1929.
JAMES M. KENDALL.