SE457684B - BILDAATERGIVNINGSANORDNING - Google Patents

Description

457 684 - "21 kärrh pipes.

The object of the invention is thus to develop a simpler and cheaper possibility of reproducing color images. According to the invention, this task is solved by means of a cathode ray tube with the features which appear from the characterizing part of claim 1. Advantageous embodiments are stated in the dependent claims. According to the invention, a single cathode ray tube generates two symmetries: mirror images. In this case, too, a single light screen can be used, but it must be divided into two parts, which are arranged symmetrically in the same plane and comprise different light elements. Likewise, only a single electron gun is needed inside the tube jacket, the two light shield portions suitably being arranged symmetrically with respect to the beam axis of the electron gun. As with the conventional tubes, a deflection system is connected to the outgoing electron beam, the tube, however, comprising special devices for generating the mirror image raster, which devices ensure that the electron beam scans the two portions of the light screen one after the other according to the mutually inverted raster patterns. As a result, lysamakamana produces both batches of images of the same pre-narrow aiika colors, which at the game of efvariyaningana duration have the iyaamnev used, together with the inertia of the human eye, visible simultaneously on the screen. These two color images are mirror images which are symmetrical relative to each other and the axis of the electron beam emanating from the electron gun.

Starting from such a picture tube, it is now possible to superimpose the two mirror images with different colors by connecting an optical system to the light screen and reproducing a single multicolor image in a common plane.

These and other details of the invention are described in more detail below with reference to the exemplary embodiments shown in the drawing. Fig. 1 shows a color rendering device according to the invention in schematic view in axial section; Fig. 2 shows the tube shown in Fig. 1 in section along line 2-2, seen in the direction of the arrow; Fig. 3 shows the light screen of the tube shown in Fig. 1 in plan view; Fig. 4 is a schematic diagram of the inverting scan circuit for the deflection device shown in Fig. 1; Fig. 5 is an overview of waveforms generated using the circuit shown in Fig. 4; and Fig. 6 shows an alternative embodiment of the optical system shown in Fig. 1 connected to the light screen shown in Fig. 3.

Equal parts are denoted throughout by the same reference numerals.

Fig. 1 shows a color image rendering apparatus 10, which comprises a cathode ray tube type tube 12 having a funnel-shaped housing 14, which has a central axis 15 and is made of any suitable dielectric material such as glass. The housing 14 comprises a neck portion 16, which terminates with a clamping foot 18 closed along the periphery, through which a circular array 3! 457 684. ning connecting pin 19 passes hermetically sealed. The pins 19 serve to provide electrical connections to the respective elements of an electron gun 20, which is located axially within the neck portion 16 of the housing 14.

The electron gun 20 comprises a filament 22, the ends of which are electrically connected via associated connecting pins 19 to an external glow current source (not shown), which supplies electrical current for heating the filaments 22. The filament 22 is axially located inside an inverted cathode shell 26. , which has a closed end with an outer coating (not shown) of electron-emitting material. The cathode shell 26 is spaced within an inverted first grid shell 28 with an opening 30 located centrally at the closed end and aligned with the adjacent closed end of the cathode shell 26. The closed end of the inverted first grid shell 28 is located near the closed end of a right-facing second grid shell 32. Centrally in the closed end of the second grid shell 32 is an opening 34, which has a larger diameter than the aligned opening 30, which is arranged centrally in the adjacent end of the first grid shell 28. The opposite open end of the second grid shell 32 insulates in isolation a reduced diameter end of an elongate focusing bowl 36. The closed end of the focusing shells 36 is provided with an opening 38 which has a larger diameter than the opening 34 and is axially aligned with the apertures 34 and 30. Thus, the electron gun 20 is arranged to generate and direct an electron beam 40 axially out of the opposite, open end of the focusing the electrode, which end constitutes the output end portion of the gun 20.

The beamforming electrodes 28, 32 and 36 in the gun 20 are insulated in isolation by means of axially extending dielectric rods 42, which as shown in Fig. 2 are spaced apart around the gun. Each of the beamforming electrodes 28, 32 and 36 is fixed, for example by welding, in bent portions on associated metal arms 44, which have foot portions which are attached to one of the rods 42. Thus, the respective beamforming electrodes form a subassembly. supported by the clamping foot 18 in that the first grid shell 28 is electrically attached to three connecting pins 19 arranged at angular intervals. Focusing electrode 36 is surrounded by axially spaced rings 46, which have inner flange portions attached by e.g. welding in annular portions on the electrode 36.

As shown in Fig. 2, each ring 46 has a resilient, projecting portion 47 and two angled rigid projecting portions 48 extending from the centerline of the focusing electrode 36 outwardly a radial distance approximately equal to the radius of the neck portion 16. Accordingly, pressure is maintained. a substantially field-free room. ' '457 684 I 4' the resilient projecting portion 47 against the adjacent wall of the housing 14, forcing the rigid projecting portions 44 to abut against the inner surface of the neck portion 16, whereby the central 30, 34 and 38 of the beamforming electrodes 28, 32 and 36 cows lie approximately on the axis centerline 15 of the housing.

The neck portion 14 is connected in one piece to an opposite end portion 50 of larger diameter on the housing 12 over an intermediate cone portion 52. The end portion 50 of larger diameter terminates with a circumferentially closed front plate 54, which is made of reaching material, eg glass. The openings are more transparent. An exit light screen 60 is deposited in a conventional manner on the inner surface of the faceplate 58 and includes two halves 56 and 58.

Half 56 is made of a light substance, for example with europium activated yttrium oxide, which emits a red light locally when it is hit by electrons from the beam 40. Half 58 is made of another light substance, eg with manganese activated zinc silicate, which locally indicates a green light when it is struck by electrons from the beam 40. Thus, the two halves 56 and 58 of the light screen 60 are arranged in the same plane and have adjacent edge portions, which are located approximately at a bang mit fl inje 15 in nzsijef 12.

Arranged on the inner surface of the light screen 60 is an anode coating 62 of electrically conductive material, for example aluminum, which reflects visible light. The coating 62 not only extends over the entire inner surface of the larger diameter end portion 50, but also extends both axially and annularly into the conical portion 52 of the housing 12. The anode coating 62 is electrically connected to an anode connection knob 64 which passes hermetically sealed through. the wall of the funnel-shaped portion 52 to serve as an electrical connection to the anode electrode of the tube 12. The anode connection knob 64 and the anode coating 62 are electrically connected to a further anode coating 66, which extends from the knob 64 towards the neck portion 14. The coating 66 is made of a suitable electrical conductive material, e.g. carbon, which extends axially and annular along the sloping inner surface of the conical portion 52 and into the neck portion 16.

Inside the neck portion 16, the anode coating 66 is terminated so that it with intermediate spaces surrounds the exit portion of the gun 20, from which the axially directed electron beam 40 emanates. Thus, the two anode coatings 66 and 62 substantially form an inverted, cup-shaped anode electrode, in which upright In operation, as shown sohematically in Fig. 1, the cathode of the gun 20 may be electrically connected through a conductor 68 to a cathode voltage socket on a polarized voltage source. 70. The first grid electrode 28 of the gun 20 can be electrically connected through a conductor 72 to a voltage socket at the source 70, which is electrically negative, to control the electron flow in the beam 40. The second grid electrode 32 of the gun 20 can be electrically connected through an associated conductor 74 to an associated voltage socket at source 70, which is more positive relative to the cathode voltage socket, and the focusing electrode 36 of the gun 20 can be connected through an associated conductor 76 to an associated voltage socket at source 70, which is even more positive relative to the source 70 cathode - voltage outlet. The anode connection knob 64 can be electrically connected through a conductor 78 to an anode voltage socket at source 70, which is at a high electrical potential relative to the cathode voltage socket of source 70. Thus, the various cup-forming electrodes 28, 32 and 36 of the gun 20 and the cup-shaped anode electrode of the tube 12 are held at suitable electrical potentials relative to the potential of the cathode 26 to focus the electrons of the beam 40 against a small spot on the light screen 60, so that locally visible light was emitted from the hit light.

A beam deflection system 80 includes an electromagnetic deflection yoke 82 located around the outside of the neck portion 16, near the conical portion 52 of the housing 14, and through which the fire duo beam 40 emitted from the gun 20 passes; The yoke 82 includes an opposite pair of interconnected line deflection coils (not shown) which are electrically connected via a conventional line amplifier 83 to a conventional line oscillator 84. The yoke 82 also includes an opposite pair of interconnected image deflection coils, as connected via a conventional image deflection amplifier 85 to an inverting deflection circuit 86. The deflection circuit 86 receives deflection signals from a conventional image sweep generator 87 and drive signals from a conventional sync device 88. The sync device 88 includes a portion of the control signal circuit 81. the drive signals to the line oscillator 84. The inverting deflection circuit 86 also receives signals from conventional video signals 89, which include an additional portion of the source 81, and supplies output signals through a normal video amplifier 134 to the first grid electrode 28 on the tube 12.

As shown in Fig. 4, the inverting deflection circuit 86 includes a dual operational amplifier device 90 of the commercial type, such as Op Amp MC 1747 from Motorola Semiconductor Products in Phoenix, Arizona. The device 90 comprises an operational amplifier 92, which has a positive input electrically connected to the output of the image deflection generator 87 and a negative input electrically connected to the contact arm of a DC control potentiometer 94 connected to a positive bias voltage. The device 90 also comprises an operational amplifier 96, which has a negative input electrically connected to the output of the image deflection generator 87 and a positive input 457 684 6 'electrically connected to the contact arm of a DC voltage potentiometer 98 connected to negative bias voltage.

The outputs of operational amplifiers 92 and 96 are electrically connected to corresponding inputs on one half of an integrated switch 100, such as Dual-in-line Package DG 201 PB, Quad SPST, CMOS Analog Switch, from Siliconix in Santa Clara, California, which has an output electrically connected to the image deflection amplifier 85. The other half of the switch 100 has its inputs connected to the contact arms of video amplification potentiometers 102 and 104, respectively, and has an output electrically connected through a conductor 106. The conductor 106 is electrically connected via the video amplifier 134 and the conductor 72 to the first grid electrode 28 (Fig. 1). Each half of the switch 100 has an associated control input connected to an output 108 of a flip-flop (F / F) 110, and has an associated control input; connected to an outlet 112 on the device 110. The device 110 'may be of any commercially available type, such as Model SN 7473 Dual J-K With Clear, from the Motorola Semiconductor Division in Phoenix, Arizona.

The device 110 has a claw] or sync input 114, which is electrically connected to the sync source 88.

Accordingly, the sync source 88 applies a drive signal voltage to the input 114 of the flip-flop 110, which as shown in Fig. 5 may be represented by the waveform 116 with regularly occurring pulses 118. When device <110 receives a pulse 118, it switches from one to the other of two switching states and thereby changes the voltages at its outputs 108 and 112 accordingly. As shown by the associated waveforms 120 and 122, a pulse 118 at the input 114 thus causes the device 110 to apply a positive voltage pulse to its output 112 for a predetermined time interval, while a zero voltage pulse is applied to the output 103. When the device 110 receives the next drive pulse 118 at its input 114, it switches states to apply a positive voltage pulse to its output 108 for an equally long predetermined time interval, while a zero voltage pulse is applied to the output 112.

Accordingly, during the predetermined interval, the switch 100 is controlled to connect the output of the operational amplifier 96 to the car deflection amplifier 85, so that it receives a voltage signal, represented by the falling sawtooth wave 124. Thereafter, the switch 100 is controlled for an equally long predetermined period. closing the output of the operational amplifier 92 to the image deflection amplifier 85, whereby it will receive a voltage signal, represented by the rising sawtooth wave 126. Consequently, the image deflection amplifier 85 will receive a composite voltage signal, represented by a waveform , 11 457 684 which starts at the maximum value A below the center value 131, corresponding to ¿the connecting edges of the screen portions 56 and 58, and ends with a value B, which deviates from the center value 151 with the setting on the potentiometer 98. The waveform 128 then has an inverted , stiganne S¿gtandSpu1s 13; which begins at a maximum value C above the center value 131, and ends with a value D, which deviates from the center value 131 with the setting on the potentiometer 94.

The deflection amplifier 85 is of the usual kind for converting the received voltage signal 128 into an equivalent electric current flowing through the yoke 82 to establish a corresponding magnetic deflection field for the electron beam 40. Consequently, the electron beam 40 is deflected (Fig. 1). successive lines to scan a grid area on the screen portion 56 from near the periphery of the faceplate 54 toward the centerline 15 of the tube 12 in the direction indicated by the double arrow 135 (Fig. 5). Thereafter, the electron beam is deflected vertically in the direction of the arrow 135 to a point near the opposite periphery of the faceplate 54 and deflected in the lateral direction in successive lines to scan a symmetrically inverted grating area on the screen portion 58 from the periphery 58 of the tube Thus, the inverting deflection circuit 86, together with the line and image deflection generators 84 and 87, respectively, constitute a mirror raster generator which causes the beam 40 to scan mutually symmetrically inverted raster areas on the display portions 56 and 58.

As shown in Fig. 1, the video circuit 89 operates via the inverting deflection circuit 86 and the video amplifier 134 in such a way that it momentarily switches the potential of the first grid electrode 28 relative to the potential of the cathode 26, thereby causing corresponding instantaneous changes in the electron current in the beam 40. when it scans the mirror grid areas on the screen portions 56 and 58.

Referring again to Fig. 4, which shows that when the switch 100 is controlled to connect the output of the operational amplifier 92 to the image deflection amplifier 85, it also connects the contact arm of the potentiometer 102 via the output conductor 106, the video amplifier 134 and the conductor 72 to the first grid electrode 28 of the tube 12. Similarly, when the switch 100, when controlled to connect the output of the operational amplifier 96 to the deflection amplifier 85, will also connect the contact arm of the potentiometer 104 to the first grid electrode 28 of the tube 12. When the beam 40 scans the respective inverted grating areas on the both halves 56 and 58 of the light screen 60, accordingly, the video signal from the video circuit 89 applied to the first grid electrode 457 684 "28 can be set to provide the desired brightness of the respective light elements in the screen portions 56 and 58.

Accordingly, as shown in Fig. 3, differently colored mirror images 136 and 138 of the same object will be generated on the screen portions 56 and 58, such as a flag 139 projecting from a flagpole 137.

Image 136 is generated »by local emission of red light from the light element in the screen portion 56, and image 138 is generated by local emission of green light from another light element in the screen portion 58. However, it is important to note that the cushion distortion in both images 136 and 138 has been exaggerated to show that this distortion is also mirror-symmetrical. Thus, due to the physical symmetry obtained in the described operation of the tube 12, image errors occurring in the image 136 when the beam 40 scans the red portion 56 of the screen 60 on one side of the centerline of the tube 12 will also be repeated symmetrically in the image. 138 when the beam 40 scans the green portion 58 of the screen 60 on the other side of the centerline of the tube 12. Consequently, if the two mirror images 136 and 138 are folded congruently over each other along their edges adjacent the center line 15, not only the two straight flagpoles 137 near the center line 15 will coincide, but also the curved edge portions of the two symmetrically placed flags 139 will coincide. without the need for any compensation or correction for image errors.

Referring again to Fig. 1, there is shown an optical system 140 optically coupled to the light screen 60, which is located in an exact, fixed relationship relative to the plane of the screen portions 56 and 58. The system 14Ö comprises a dichroic mirror 144, which transmits red light and reflects green light, is placed flush with the center line of the tube 12 and the connecting edges of the screen portions 56 and 58. A second mirror 142 reflects red light from the screen portion 56, is located at an angle of about 45 degrees to the plane of the screen portion 56 and to the dichroic mirror: 144 planes. A beam splitter 146, which transmits red light and partially transmits, partially reflects green light, is located at an angle of about 45 degrees to the plane of the screen portion 58 and to the plane of the dichroic mirror 144.

In operation, red light is reflected from the image 136 generated by the screen portion 56 from the mirror 142 and passes through the mirror 144 to the beam splitter 146; where a significant portion of the red light continues through the beam splitter 146 to the eye 148. On the other hand, green light is reflected from the image 138 generated by the screen portion 58 partially from the beam splitter 146 to the dichroic mirror 144, where it is also reflected back to the beam splitter. 146. A significant portion of the green light continues through the beam splitter 146 to the eye 148. Emcdan the images:, son 9 '457 684 136 and 138 are symmetrical mirror images and the system of optical components is calculated to provide equal optical path lengths for the red and the green rays from the corresponding discrete areas of these images to the eye, and the red and green light rays from the corresponding discrete areas hit the eye from identical directions, these corresponding discrete areas will be seen by the eye 148 as coincident. The virtual image plane 150 represents the surface in which the images 136 and 138 appear to be located and superimposed on the eye 148. The optical distance from the virtual image plane 150 to the eye 148 is identical to the optical distance from the images 136 and 138 to the eye 148, and can be seen as created by unfolding the paths of the light rays at the reflection surfaces. The color of each of the discrete areas of the multicolor image is determined by the relative brightnesses of the red and green lights in the corresponding discrete areas of the images 136 and 138. The red brightness of the image 136 and the green brightness of the image 138 can be controlled by the amplitudes of the video signals applied between the grating 28 and the cathode 26 during the time intervals when the beam 40 scans the red portion 56 and the green portion 58, respectively, of the light screen 60.

As shown in Fig. 6, an alternative embodiment 140a of the optical system 140 may include the optical elements 142a, 144a and 146a which are similar to the corresponding optical elements 142, 144 and 146 in the system 140, and a further mirror 152. The mirror 152 is highly reflective of green light from the screen portion 58 and is located on the outside of the beam splitter 146a, parallel to the screen portion 58, and at an optical distance from the screen portion 58 which is equal to the optical distance from the screen portion 58 to the dichroic mirror 144a. Accordingly, the component of each light beam from the screen portion 58 passing directly through the beam splitter 146a will be reflected by the mirror 152 back to the beam splitter 146a, where a portion of said component is reflected by the beam splitter 146a to the eye 148 along the same optical path as that of the component. reflected by the mirror 152. Since the optical paths of these different green light beam components are identical when they hit the eye 148 and are equal in total length from each light emitting point to the eye, each such light emitting point will be seen as a single pixel. of the eye 148. It should be appreciated that the purpose of the mirror 152 is to recover a significant portion of the green light that would otherwise be lost to the system due to the beam splitter 146. As with the embodiment of Fig. 1, corresponding discrete areas are seen. of the images 136 and 138 of the eye superimposed on the virtual image plane 150. Adhesives, such as those used to fa 457 684 10 These and other modifications should be apparent to those skilled in the art. For example, the composite waveform 128 from the inverting deflection circuit 86 may be changed to cause the beam 40 to scan the grating area 136 of Fig. 3 from near the centerline 15 outwardly toward the periphery of the faceplate 54, and then the return beam. to pass the center line 15 to scan the grid area 138 from in the vicinity of the center line 15 outwards towards the opposite peripheral part of the front plate 5 4. Likewise, the mirrors 142, 144 and 146 in rig 1 can be replaced with suitably coated surfaces on rectangular prisms located above the screen portion 56 respectively 58 on the display 60. Alternatively, the mirrors 142, 144 and 146 can be kept aligned with each other and relative to the light screen 60 by filling the spaces between the faceplate 54 and the mirrors with optically clear, index-matched implosion panels on faceplates on picture tubes. Furthermore, it may be desirable to insert any suitable optical element, such as a circular polarizer, between the screen portion 58 and the beam splitter 146 or 146a to improve contrast by preventing green light from a point on the screen 58 from being reflected back in excessive extent and illuminate the remaining part of the screen portion 58. Furthermore, the front panel of fiber optic or other suitable character attan 54 can be made of material with light transmission elements other than those of glass. Furthermore, the deflection yoke, when aligned in the desired manner, can be mounted firmly on the outside of the tube 12 in a conventional manner for the manufacture of tough cathode ray tubes. Furthermore, a magnifying lens, contrast enhancement filter and / or other types of optical means can be placed between the optical system 140 and 148 to magnify the final multicolor image, increase the contrast of images and / or produce a projected real image. 56 and see aaresseras airekt, eg 1 aatorbiiaterminaier, instead of through the described scan.

Overall, the invention thus enables the reproduction of multicolor images in simpler and cheaper ways than with the devices mentioned in the introduction. Furthermore, it should be clear from the description above that the invention can be modified in many ways without the actual idea of the invention. Invent to the described embodiments. thereby leaving no one is thus not limited

Claims (7)

457 684 11 P a t e n t k r a v: Image display device, comprising a cathode ray tube (12) with devices for generating and deflecting an electron beam (40) and a light shield (60), and deflection circuits, characterized in that the tube has a single electron gun, that the light screen (60) consists of two parts (56, 58) which each give their own color in the case of electron irradiation, that the deflection circuits are designed to control the deflection of the electron beam (40) so that it generates mutually mirror-symmetrically arranged images on the two light screen portions (56, 58). , 138, Fig. 3) in different colors of the same image content, and that an optical device (140) is arranged on the outside of the tube in front of the light screen (60) and is designed so that it combines the two images into a common , virtual multicolor image (150), which can be viewed from the side of the tube. Device according to Claim 1, characterized in that the two parts (56, 58) of the light screen (60) are arranged symmetrically. Device according to Claim 1 or 2, characterized in that the two parts (56, 58) of the light screen (60) lie in a plane aligned with the front plate (54) of the tube. Device according to one of the preceding claims, characterized in that the casing (14) of the tube has an center axis (15), and in that the two parts (56, 58) of the light screen (60) are symmetrically located relative to the center axis (15) of the tube. Device according to one of the preceding claims, characterized in that the two parts (56, 58) of the light screen (60) are each made of a different light substance, which gives its own color. Device according to one of the preceding claims, characterized in that the tube 1 has devices (20, 80) for directing the electron beam (40) towards corresponding fields on the two parts (56, 58) of the shield (60) for generating the mirror symbols. - the metric images (136, 138). ' Device according to claim 6, characterized in that it has control circuits for momentarily varying the current of the electron beam (40) during the scanning of the two parts (56, 58) of the light screen (60).