US2281637A - Cathode ray television receiver - Google Patents

Description

May 5, 1942, T. w. SUKUMLYN 2,231,637

- CATHODE RAY TELEVISION RECEIVER Filed April 2, 1938 3 Sheets-Sheet 1 Hmm mul INVENTOR Thomas W. SuKumlyn BY ATTORNEY T. W. SUKUMLYN cA'rHoDE RAY TELEVISION RECEIVER May '5, 1942.

Filed Ap'ril 2, 1938 3 Sheets-Sheet 2 INVENTOQ Tho qs WS BY j umlyn d/MA/ ATTORN EY May 5, 1942.

T. W. SUKUMLYN CATHODE RAY TELEVISION RECEIVER Filed April 2, 1938 3 Sheets-Sheet 3 INVENTOR Thomas W Su umlyn WMA/'21110 ATTORNEY 'Patented May-5, 1942 Usl-reo STATES PA'rsNr orsics CATHODE BAY 2,231,637 TELEVISION iiscsrvsn Thomas W. Snkumlyn, Los Angeles, Calif.

Application April 2, 1938, Serial No. 199,687

(CielQSd-S gli? l Ardclaims.

This invention relates to a television receiver, in which a cathode ray tube is utilized.

In television reception, the ultimate function of the receiver is to produce an image corresponding to the scene transmitted. invariably, this image is produced on a screen by illuminating elemental areas in succession at a rapid rate. This process is called scanning. The intensity of illumination is varied in accordance with the requirements oi the image to be produced: and

the entire screen is scanned often enough thatA the image produced is seen in its entirety by .virtue of the phenomenon oi persistence of vision.

' All this is well understood. In using a cathode vide a lens or projection system for use with a ray tube lor television reception, it has been proposed to use a iiuorescent screen as one wall oi the tube, and to cause iuorescence of elemental areas in succession, by scanning the screen with an elemental beam of electrons.

The 'uorescent screen is viewed by the audience. In all such devic, one of the important problems is to produce a sumciently brilliant image, in spite oi the fact that the illuminating beam passes over the elemental` areas rapidly. l.

It is one o2 the obiects ci this invention to prolong the period ci illumination on a screen; and particularly by ensuring that elemental areas ci the screen are lett illuminated for a short period, even after the scanning beam has passed'. For example, the scanning beam ci electrons in a cathode ray device may be operative to open light valves, which remainopen for ,a period even after the beam passes. In one the type oi reilecticn can be such that the area does not immediately revert to diiuse reiiection tion to make it possible to alter the character of" reilection of elemental areas in succession.

Instead of a change in redaction properties. the same effect may be obtained by alterins the refractive character of the member upon which the beam strikes. For example, the elemental areas may ne arranged to become translucent instead of opaque. Under any circumstance. the

scanning system that improves the quality ci' the image on the viewing screen this is accomplished.

by providing means to prevent diused light in the system reaching the screen.-

This invention possesses many other advantages, and has other objects which may be made more easily apparent from :a consideration oi several embodiments oi the invention. For this purpose there are shown a lew iorms in the drawinss accompanying and forming part o! the present specication. These forms will now be described in detail, illustrating the general principles oi the invention; but it is to be understood that this detailed description is not to be' in a limiting sense, since the scope oi the invention is best deilned by the appended claims.

Referring to the drawings:

Figure 1 is a diagrammatic representation ci a system incorporating the invention, the cathode ray tube being shown in section: and

Fiss. 2. 3, 4, E, 6, and 'I are fragmentary views similar to Fis. l, oi modified forms oi the invention. A

The television system illustrated is to provide two functions that are in general common to many television receivers. A light beam (such as si) is caused to aii'ect elemental portions oi a receptor screen i in succession at a rapid rate to scan the screen completely; often asmanyassixteentimeaperseccnd. Theother function' is a variation oi the intensity or the beam t5 which scans the screen I in accordance with the variations in the light values ci the corresponding elemental portion o! the scene that is beine reproduced.

m the present instance, die electrical :niguna corresponding to the variations in this light intensity are translated in a modulation receiver 2, shown as llsvins,v an elevated collector or antenna t. and a ground connection 6. Since the ability of the surface or member to transmit ilcircuits and amplifiers included in such a modu- Ythe cathode ray beam I4.

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lation receiver are well known, further explanation thereof is unnecessary.

The output leads and 5 from the receiver 2 may be connected to a device energized in accordance with the impulses received by the receiver 2. This der/*ice is illustrated as a cathode ray tube l. This tube is shown in this instance as having its small end 8 made of glass or the like, appropriately sealed and joined to the metallic diverglng portion 9. The glass portion 8 is provided to make it possible readily to seal therethrough the leading in wires or connectors for the various electrodes. One of these electrodes is a lament III heated as by a battery II and serving as a source or electrons. Near this electrode Ill is the .control electrode or grid I2. An anode I3 of tubular form serves to direct the cathode ray or electron stream I4 from the heating filament ID toward the large end of the tube l.

Since one of the leads 6 from the receiver 2 is connected to the control electrode or grid i2, and since the other lead 5 is connected to the lament III, the impulses passing to these two electrodes in the form of varying potential diierences produce corresponding variations in the intensity of the cathode ray I4 in a well understood manner. The tubular directing anode I3 is arranged to be kept at a positive potential with respect to the illament I0, as by the aid of the battery I5.

The directing anode I3 with its battery I5 serves to accelerate the stream of electrons passing through the anode I3. In order further to accelerate the electrons, the metallic portion 9 of the tube 'I is connected to the positive end of battery Il, whereby this metallic portion serves also as an accelerating electrode.

The mode of operation ef such tubes being we known, further description is unnecessary.

The large end of the tube I is closed tightly by a member I8 which may be in the form o a thin membrane. either of metal or of non-conducting material. It is held in gas tight relation with the end of the tube For example, this may be accomplished by a member 20 forming a vacuum chamber 22 on the right hand side of the member I8. This member 20 is shown as provided with a flange 2I through which the bolts or screws I9 may pass for clamping the membrane I8 tightly to the end of the tube l. The chamber 22 formed by the member 20 is utilized in a manner to be hereinafter described in connection with the transmission of illumination to the screen I.

The membrane I8 is arranged to be scanned by This can be accomE plished, for example, by the aid of the scanning receiver 23, having the elevated collecting conductors or antenna 24 and a ground connection 25. This receiver 23 is caused to affect two sets of influencing devices 26 (either coils or condenser plates), for deflecting the beam I4 in a horizontal direction. Thus the elements 26 can be connected as by leads 2l to the receiver 23 by way of a high band pass illter 28. These elements 26 can be arranged in such a way as to deflect the beam I4 in a horizontal direction. can be arranged to pass only high frequency impulses to elements 28, whereby a very rapid to and fro motion of the beam I4 is secured.

In order to deflect the beam I4 simultaneously at a slowerrate in a vertical direction, elements such as-28 (either coils or condenser plates), are fed low frequency currents through conductors The lter 28 3U and a lowband pass lter 3|. These elements 75 accres? are disposed at right angles to the elements 28, with respect to the axis of tube I.

The combined results of the elements 28 and 25 are cyclically to cause the beam I4 to trace a series of substantially horizontal lines on the membrane I6, each line being vertically spaced from the preceding one. By proper arrangement of the circuits, this scanning is produced at the desired rapid rate. At the same time, the control electrode I2 of the tube I causes a variation in the intensity of the cathode ray Id.

In accordance With Well understood arrangements, such a television receiver could comprise a fluorescent screen in place of the membrane I8. In that case the screen-is excited by the cathode rays to luminesce the elemental areas in accordance with the intensity of the rays which strike these elemental areas.

` In accordance with the present invention, however, the membrane Ii! is so arranged that elemental areas affected by or receiving the beam I4 are caused to vary the capability of the membrane to transmit illumination, either by reflection or refraction. The variation in the light transmission qualities 1s such that even after the beam I4 leaves an elemental area of membrane I8, this variation is nevertheless effective for a short interval. Accordingly, the period of illuminationof corresponding elemental portions of the screen I is very greatly increased, with an attendant greatly improved brilliance. In other words, the elemental areas of member I8 act only as valves for controlling a rather intense source ot illumination; this source is independent of the ray I4; accordingly greatly increased light energy may be thus utilized to produce the desired image on screen I.

In the present instance, a beam from n itense source of light 32 externalof the tube 'I is shown as passing through a collimating lens system 33, and through the transparent window 34 of member 20, to illumine the right hand surface of the membrane I8. Light thus falls over the whole active area of the membrane Il,

but due to the action of the stream of electrons` carried by ray I4, the light reflecting qualities ot that portion of the area which is subjected to the eiIect of the ray, is altered.

For example, it is known that the impingement of electrons upon a member, such as Il, causes the evolution of heat. This heat could be used for example to aifect a layer 35 deposited on the right hand face of member Il so as to expose the surface of layer I8-adjacent the ray I4, while the heating eifect of ray I4 continues.

Layer l!! is formed on membrane I3 before the membrane is placed in the tube assembly. Thus 'it forms in effect an integral part of membrane I8 and may be termed an integral layer. This right hand surface of member I8 can be specu4 larly reflecting, as for example by the ald of a polished surface. The layer 35 can be a thin lm of parafiln, wax or'the like, that may be readily melted and thereby to form a transparent layer when melted, in place of'a substantially opaque layer when solidified. Accordingly, the heat generated by the striking of the ray I4 on the left hand surface oi membrane I8 produces a. melting of the wax to expose the specularly reilecting surface of this member Il. Since the wax remains melted for an appreciable period, even after the ray I4 sweeps away from it, it is seen that the specular reilection persists for a much longer period than the impingement of the ray I4.

period oi` light eillciently to screen I.

"rnc man@ m the reflective quality o: the membrane I8 is illustrated in Fig. 1. Thus for areas not ailected by the heat of ray I4, the reiiection of light from source 32 is diused as indicated by the arrows 33. However, at the spot l .31 where the layer Ilis melted, there is specular reilecticn of the elemental light beam 38 along the focal point of the lens system and is of auch size as to pass only an elemental ray from lens QI to lens 44.' 'I'he diiused light reected by the membrane I3 from source 32 through lens 6I is not passed to screen I since it is not focussed by lens 4I 'on aperture 42, but an elemental beam, or ray. as 33, is focused on the aperture 42 and is thus passed without hindrance. This results in an improved image on the screen, since the cutting oi! of this diil'used light results in a e darker screen.

Now as the ray I4 alters its position, the specular-ly reflecting elemental area on membrane I8 is correspondingly altered. The result is that the direction of the reflected beam, such as 39, also alters. There is thus a corresponding change in the position of ray 45, and therefore screen I is scanned in accordance with the scanning of the diaphragm I8.

This layer of wax 35 is but one material that could be used for obscuring the surface of member I8. When it is melted'by the heat produced by the electron stream of ray I4, it remains transparent, but resolidiies upon member I8 after a short period oi time. In the meanwhile, of course, the melted spot is eective to pass Thus a brilliant source of light 32 can be properly controlled.

It is not essential that the layer 35 be of wax. Other materials operate in substantially the same Imanner. For example in Fig. 2 the membrane 46,

corresponding to membrane I8 of Fig. 1, is shown as having a thin volatile metallic layer 31 on its right hand surface. This material when deposited may form a specular reilecting surface. When it is evaporated from a spot such as 94. the corresponding surface of member 4 6 forms a diuse reilector. Under any circunistances, there is a change in the light transmisc sion quality of the surface exposed to the light rays; accordingly, as illustrated, the image produced in this form of the invention is negative. This is true because there is a reduction in lllumination where ray I4 strikes membrane 48, the diuse reflecting surface of the membrane 'serving to disperse the light instead of reilectlng it.

In order to insure that the vaporized material will recondense upon the membrane 4B and not upon any other part of the tube 1, provisions may be made for heating the other parts of the tube; as for example by an electrical heating coil 49 placed upon an extension 50 of the member 48. In this way the recondensation of the volatilized or vaporized material is conilned to the right hand surface of member 4S.

In thelens system shown in Fig. l, each reected ray 33 is caused to pass through the focal' aperture 42, and thence through the lens system 44 on to the screen I. As the position of ray I4 changes, the position of the reilected ray 33 corf ray I4. In this form only a single window 53 is provided for the end member 54 of tube l. An intense light from a source 55 is passed through a focal aperture 58 in a screen IDG and thence through a collimating lens system 5l. This light illuminates the entire active area of the coating 52. That elemental area adjacent the place where ray I4 strikes the membrane 6I maybe rendered specularly reilecting, or diiusely reflecting. The ray 53 reflected from that spot is intended to pass through the lens 5l, which is so arranged as to pass all such reected rays through another focal aperture 59 in screen |90. Thence the reilected ray is passed through the lens 60 and on to a screen, not shown. In this way the lens system 51 replaces both of the lenses 33 and 4I. As in the first form, aperture 69 is only large enough to pass the elemental ray 58, hence screen |00 prevents the diiused light from lens 5l being passed to the screen and improves thequality of the image projected there.

In the form of the invention illustrated in Fig. 4, the membrane 6I is shown as forming one boundary for a narrow space 62. The other boundary is formed by a thick member 63 capable of transmitting light; for example, a heavy piece of glass. Volatillzable material is placed within thel narrow space 62 which is normally condensed upon the corresponding surface of member 63. This member is purposely made with a large exposed area to cool the surface upon which the material is to be condensed. 'I'he material on the member 63 adjacent the place where ray I4 strikes the membrane 6I is evaporated, and a change in the In this case the volatile material is intended to provide specular reection except for that area which is subjected to the heat of ray I4; at that point, the light passes through the space 52 and is diffused on the surface of membrane 6I.

In the forms of the invention thus far described, the light is caused to be reiected from a surface of a membrane. In the form of the invention illustrated in Fig. 5, a refraction arrangement is illustrated.' In this form the tube 34 is shown as having a membrane 65 held in place by a cap or cover 6l. Here light from the source 68- passes through the colllmating lens system 38 and the transparent window lil formed in the extension II is caused to illuminate the entire active area of the membrane 65. This membrane 65 may be made of translucent material to refract the light provided the layer 'I2 on the right hand side ofn light transmitting quality of the surface of member 63 is varied.

or tube 64. The light S8 thuspated at the exposed surface.

may be of such a character that it melts rst and then evaporates, later recondensing on the membrane 55.

The refracted ray is shown as passing through a transparent window 'l5 formed in the member 61, and thence through a condensing lens 'I6 and focal aperture Il' in a screen IBI through alens system 18 on to the screen 1S.

The scanning of the screen 'i9 occurs as described in connection with the form of the invention shown in Fig. 1, except that the ray illuminating the screen 'i9 is refracted instead of being reflected. This refraction occurs for a period corresponding to the period of volatilization of the layer 12 from the spot affected by the heat of the ray I4.

In the form of the invention illustrated in Fis. 6, the tube G4 is shown as being provided with an end cover member 88 of heavy glass, such as member 63 in the form of Fig. 4. In this form the membrane I in coniunction with the ad jacent surface of the member 35 forms a confined space 8e2 lor the volatile material. Due to the large cooling surface of the member 30, this volatile material is caused normally to condense on the adjacent surface of member lill. When the ray id, however, volatilizes the material at a spot, a corresponding ray 83 is retracted and passed through a lens system @e te a screen, not shown.

The cooling effect to insure that the volatile material will recondense upon the desired surfaces may be of the type shown in Fig. 7. In this form the tube 85 is shown as having an entering extension 86 and an exit extension al. The source 88 passes light into the-tube l'i, which light is intended to be reected from the surface of member 89, upon the left hand side of which is deposited the volatile layer 90. In

- order to insure that the volatilized or vaporized material will recondense upon the member di), a'

cooling coil 9| in contact with the member as may be utilized. This may be in the form of an air or water circulating coil.-

The refracting lenses in this form of the invention may be quite similar to those illustrated in Fig. 1. Whenl ray I4 strikes any elemental area 96, the volatile layer 90 is removed and reection is prevented because the light is dissi- Accordingly in this form a negative image is formed on the screen. If desired a protective transparent membrane or plate B1 for the volatile material SU may be provided.

The forms of the invention illustrated in Figs. l, 3 and 4, are made the subject matter oi a fh visional application Serial No. 229,146, filed February 2, 1942, and entitled "Cathode ray television receiver.

What is claimed is:

1. In combination, a cathode ray tube, a memmember by the ray, a source of illumination for said surface, a volatilizabie coating on said member normally obscuring the reilectlng surface, and volatilized by the heat of the ray, means forming a chamber of which said member forms a Wall, and in which said coating is volatilizfed,

and means adapted to maintain said member at a temperature below that of the chamber, thereby ensuring that the volatilized matter will recondense on the member.

2. The process of transmitting light in accordance with television signals and by the aid of a moving cathode ray, which comprises passing the ray successively over elemental areas of a light transmitting member, illuminating the surface of the member, said surface being arranged to cause dispersion of the illumination, causing the ray where it impinges on the meniber to vary the transmission of light by the member so that an elemental ray oi light is passing the transmitted light through a converging lens system, and then through a focal aperture in a focal screen, said aperture being substantially only large enough to pass said elemental ray. whereby the dispersed light transmitted by the lens system is prevented substantially from passing the screen. -1

3. In a scanning system operated by transmitted light ,and including a source of light emitting substantially parallel rays, a transmitting member .upon which said rays implnge, said member causing dispersion of the rays, means for varying in accordance with received television signals, the light transmitting qualities of ele.- mental areas of said member to reduce the dispersion of said areas so thatl elemental rays are transmitted thereby, a converging lens system adapted to receive the light from the transmitting member, and means forming a focal aperture 'at the point of convergence. said aperture being capable of passing substantially only said elemental rays.

4: In a cathode ray tube, means forming a chamber having a. wall forming a light transmitting member and adapted to be scanned by the cathode ray, seid chamber having a vapor pressure neighboring a vacuum, said wall serving to divide the chamber from the tube, material on the wall and within the chamber i'or varying the light transmitting qualities of said member in response to impingement of said ray on the wall, said ray being modulated in accordance with received television signets. and means for controlling the temperature of the chamber independently of the temperature of the tube.

THOMAS W. SUKUmYN.

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