JPH05232438A - Television receiver - Google Patents

Abstract

PURPOSE:To obtain the projection type television receiver which is lower in cost, lighter in weight and smaller in size than television receivers constituted by using cathode ray tubes and has high production efficiency. CONSTITUTION:This television receiver has an image display device 1 of a CRT, etc., a ferroelectric liquid crystal layer or an optical amplifier cell 2 having the ferroelectric liquid crystal layer, optical shutters 7, 8, 9 for selecting red, green and blue light beams and a light source 3. The videos corresponding to the red, green and blue displayed by a display body 1 are written into the optical amplifier cell 2 and the images corresponding to the respective colors written in the optical amplifier cell 2 are read out by the red, green and blue light beams selected by the optical shutters 7, 8, 9. These images are synthesized, by which color projected images 12 are obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention specifically relates to a video signal transmitted from a terrestrial television station, a satellite television station, a cable television station or a television image recording device (a video deck, a laser disc, a magneto-optical disc, etc.) provided individually. It proposes a device for displaying on.

[0002]

2. Description of the Related Art Conventionally, as a device for concretely displaying a video signal transmitted from a terrestrial television station, a satellite television station, a cable television station, or a television image recording device (a video deck, a laser disc, a magneto-optical disc, etc.) provided individually. Has adopted a method in which an electron beam is blown in a vacuum tube called a cathode ray tube or a CRT to cause a fluorescent surface as an object to emit light.

Initially, the diagonal of the display body was often 12 to 14 inches, but in recent years, the size of 20 inches, not to mention 30 inches, has come to appear due to the demand of the world.

When the diagonal is 30 inches, the depth is about 30 inches, and the thickness of the glass forming the glass exceeds 1 cm in order to maintain the strength. Further, as another device, a system of enlarging and displaying a high-luminance CRT with an optical system and projecting it on a screen has been proposed, and is used for a large display area.

[0005]

In the case of a television receiver using a cathode ray tube, if the display surface exceeds 30 inches, the total weight will easily exceed 100 kg.
In general households, it is difficult to place a heavy load exceeding 100 kg unless the place is limited.
In addition, it is difficult to move the weight manually when the layout is changed, which has been an obstacle to its spread to general households.

Therefore, a projection-type television receiver has been proposed for solving the weight or for obtaining a large screen more easily, but there is a limit to the improvement of the brightness of the original high-brightness cathode ray tube, and the expansion. The brightness itself on the screen was very low. Therefore, not only the screen is dark, but also the contrast ratio in the front is high because the image is magnified by the optical system, but the contrast ratio from the oblique direction is very inferior to that of the cathode ray tube method. Further, although many projections using TFT panels are produced, there is a problem that the production yield is not easily increased due to the complexity of the TFT production process.

Further, since three active matrix type display devices are used as the display body, and the low yield can be raised to the third power, the overall yield is extremely low, which causes an increase in cost. It was

[0008]

Therefore, in the present invention, 1
The images from the two low-brightness display bodies are dispersed, and the image of the dispersed light is selectively written on one surface of the optically writable liquid crystal cell in correspondence with the images of the three primary colors. By irradiating and reflecting the reading light spectrally divided into the three primary colors on the surface of, the image written in the liquid crystal cell is read, and the images read from this liquid crystal cell are combined to obtain the light brightness and high performance. It realizes color projection.

In this case, a low-luminance CRT, which has been used in production so far, can be used as a display member, and color projection can be performed while optically amplifying. Further, a TFT panel, electroluminescence, plasma display or the like can be used as the display.

FIG. 1 shows a block diagram of an example of the present invention. The display body 1 showing a television image is an object that sequentially forms images corresponding to red, blue, and green for a certain period of time. The light is sent to the optical amplification section 2. In this case, the display body is a CRT, a multiplex drive liquid crystal panel having a light source behind it, an electroluminescence panel,
A plasma display or the like is used.

This display body is merely for forming an image and does not have to be a color, but is black and white or two colors corresponding thereto. These lights are sent to the cells of the amplification section and become write signals.

The optical amplification section 2 will be described. FIG. 2 shows a schematic diagram thereof. A translucent conductive film 17 formed on the glass substrate 16, a photoconductor 18 whose electric resistance decreases when irradiated with light, and a dielectric layer 1 which further reflects light thereon.
9. A second substrate having a first substrate on which a light blocking layer 20 is further formed, a translucent conductive film 22 formed on a glass substrate 21 and a uniaxial alignment film 23 for uniaxially aligning a ferroelectric liquid crystal.
The second substrate is composed of a ferroelectric liquid crystal layer or an antiferroelectric liquid crystal layer 24 held between the first and second substrates at a constant interval.

The writing light 26 is incident from the first substrate side. Then, the resistance of the photoconductor in the light irradiation part having an image is reduced, and the electric field is applied to the liquid crystal only in that part, so that the liquid crystal is switched and the same image as the write signal is obtained in the light amplification part liquid crystal layer 24. It will be a matter. Furthermore, since the ferroelectric liquid crystal or the antiferroelectric liquid crystal is used for the liquid crystal layer, the image is retained not only when writing in the amplifying section but also when not writing. The writing light intensity is 0.5 to 5.0 mW / cm ² .

The 300 W metal halide lamp 3 shown in FIG.
The light emitted from the light passes through the dichroic mirrors 4, 5, 6 and is split into blue, green, and red, and then the light to be sent next is selected by the liquid crystal light shutters arranged for the respective colors. Then, by collecting the red, green, and blue lights by the half mirrors 13, 14, and 15, the selected blue, green, and red lights are
The light is incident from the second substrate side through the deflector 13 which is a deflecting plate.

The reflected light from the liquid crystal layer passes through the analyzer 10 which is a deflector plate paired with the deflector 13 to form an image with light and dark. Through the lens system,
It is a system for projecting a large area of 50 inches (the size is not limited) on the wall. The maximum luminance on the wall at this time was 200 cd / m ² . The light amount is much larger than the light amount of the display unit of the writing unit, and the light amplification is substantially performed. Therefore, a sharp color TV image with extremely high brightness was obtained on the wall.

Although red, green, and blue are used as the three primary colors in the structure of the present invention, a combination of other colors may be used.

[0017]

【Example】

[Example 1] An example using the present invention will be described.
The structure of the apparatus is as shown in FIG. As the image display body 1, a 3 inch CRT for normal light and black display was used. In this image, images corresponding to red, blue, and green are displayed for 5 milliseconds each, and the light corresponding to each primary color can be sequentially advanced to the amplification cell by shifting to the next image.

Next, the structure of the optical amplification section shown in FIG. 2 will be described. As the substrate 16 on the optical writing side, an ITO film 17 as a transparent conductive film was formed on a transparent substrate 16 such as glass by a sputtering method or a vapor deposition method. The film thickness is 500 to 2
It is 000Å. Next, bismuth silicon oxide was formed as a photoconductor layer 18 thereon by sputtering or vapor deposition. Alternatively, photoconductive amorphous silicon or the like may be formed by a CVD method. These reduce the resistance by light irradiation by about 3 to 4 digits.

An insulating dielectric film 19 and a reflective film 20 are formed on the film by vapor deposition or sputtering. The film thickness is 100
It is from 0 to 4000Å. This completely separated the light on the writing side and the light on the reading side. If this is not done completely, the resistance of the photoconductive layer will be reduced by the light on the reading side with a large amount of light, and the liquid crystal will respond.

On the other hand, as a substrate on the light reading side, ITO 22 was formed on a glass substrate 21 and then polyimide 23 was formed on the glass substrate 21 and uniaxially oriented. The optical reading side substrate and the optical writing side substrate were fixed at a constant interval of 1.6 to 1.8 μm. In order to keep the distance, a catalyst sphere made of catalysis was used. Next, a ferroelectric liquid crystal material 24 having an optically active group in the liquid crystal molecule was injected by the vacuum method. With this cell thickness, the bright transmitted color of the liquid crystal becomes white.

This optical amplification section forms an image by optical writing as described above. Since the resistance of the photoconductive layer in the light irradiation part of the image irradiated from the display body is lowered, an electric field is applied to the liquid crystal part to respond. Further, the liquid crystal in the portion not irradiated with light does not respond. Therefore, an image similar to that of the display body is formed on the liquid crystal portion.

The reading section of the optical amplifying section will be described with reference to FIG. The light of the high-pressure halogen lamp 3 of 200 mW / cm ² passes through the three dichroic mirrors 4, 5 and 6 and is split into three colors. Further, only one color of each color is selected by the optical shutters 7, 8 and 9 and the light amplification section. Is irradiated from the side of the second substrate. Deflection plate 1 which is a deflector in the amplification section
The light that has passed through 3 and is incident is reflected according to the alignment direction of the liquid crystal, and passes through the polarizing plate 10 that is an analyzer to form a bright and dark image. Placing the optical shutter in front of the optical amplification cell is easier in terms of manufacturing because it is not necessary to focus the image.

The configuration of the optical shutter will be described. For the optical shutter, a panel using ferroelectric liquid crystal was used. The block diagram is shown in FIG. Ferroelectric liquid crystal panel has 10
It is a product that enables a high-speed response of about 0 μsec and a high contrast ratio. In the case of the television receiver according to the present invention, high speed response is indispensable, and the ferroelectric liquid crystal cell is very useful.

A method for manufacturing the optical shutter will be described below.
First, a set of 500 to 2000 liters of a transparent conductive film ITO 29 is formed on a transparent glass substrate 28 by a sputtering device. Then, one substrate side was coated with polyimide 30 by a spinner or offset printing method, and baked at 280 ° C. LQ5200 manufactured by Hitachi Chemical was used as the polyimide. Then, it was rubbed by a roll made of cotton velvet and fixed to the other substrate with epoxy resin at an interval of 1.6 to 1.8 microns. Next, a ferroelectric liquid crystal 31 containing a phenylpyrimidine skeleton was injected at about 100 ° C. by a vacuum method. After that, the polarizing plates 32 and 32 'were pasted to form a cell for a light shutter. When the cell was driven by a square wave of 10 V, the response speed was 1/10000 second and the contrast ratio was 50: 1 to 150: 1.

The voltage waveform applied to each cell and the optical response in the system described above will be described. First, the drive of the optical amplification cell will be described. The switching of the ferroelectric liquid crystal is performed by the difference of the driving voltage direction. Considering this, it is necessary to write the image of the display body in real time. Therefore, the cell surface was darkened with a voltage of 10 V, and then a voltage of -5 V was applied. At that time, since the resistance value of the photoconductor layer in the portion irradiated with light is lowered, an electric field is applied to the liquid crystal only in that portion to respond, and an image similar to the CRT image can be formed in the liquid crystal cell. Like It is necessary to sequentially write images corresponding to red, green, and blue in the light amplification cell every 5 msec.

Next, the response of the optical shutter, the drive waveform, the drive waveform of the optical amplification cell, and the relationship between the CRT and the projected image will be described. This will be described below with reference to FIG. First, the optical shutter corresponding to red (R) is 5 at a voltage of 10 volts.
It is in the transparent state for milliseconds. In the meantime, green (G),
A voltage of −10 V is applied to the blue (B) optical shutter to make it non-transmissive. At this time, the light amplification cell is irradiated with only red light, and a red image is formed on the wall. Then, in the next 5 milliseconds, the green optical shutter is in the transmissive state and the red and blue are in the non-transmissive state. At this time, a green image is displayed on the wall. In this way, red, green, and blue sequentially form images of respective colors on the wall. Of course, the CRT that is the display
Displays the image corresponding to each color signal every 5 milliseconds in accordance with the operation of the optical shutter.

At this time, since a pulse voltage of 10 V is applied to the optical amplification cell at intervals of 5 ms, the image is rewritten every 5 ms. Thus, as shown in FIG. 4, the red image, the green image, and the blue image are sequentially
It is formed according to the image sent from the display body.

FIG. 4 shows the response of a part of the liquid crystal, and it goes without saying that the liquid crystal responds according to the image sent at the place of the liquid crystal.

By the above operation, 180 images of each screen of red, green and blue are drawn in 1 second and 60 images of the composite image of 3 colors are drawn in 1 second by amplifying the image of the CRT which is the display. Can be done.

[Embodiment 2] In this embodiment, the writing light display body 1 is a liquid crystal cell having a TFT. The liquid crystal cell is a liquid crystal cell that does not have a color filter having 320 × 220 pixels. Fractional distillation for cell production is relatively high because there is no color filter inside the cell. The TFT has a semiconductor layer made of amorphous silicon or polysilicon. If a backlight is provided behind this liquid crystal cell, the light intensity will be 1 to 5 m.
A liquid crystal panel having a high contrast ratio of W / cm ² and a contrast ratio of 100: 1 can be obtained. This liquid crystal cell was placed at the display shown in FIG. 1 and the whole was driven. The projected image on the wall has a contrast ratio of 100: 1 and a maximum brightness of 150.
A bright display of cd / cm ² was obtained.

[Embodiment 3] An optical amplifying section (optical amplifying cell) shown by 2 in FIG. 1 was similarly produced by the method described in Embodiment 1. However, in the present example, a liquid crystal cell was manufactured with the size of the ball-shaped ball serving as a spacer being 1.5 μm in diameter. Also,
A silicon oxide film having a thickness of about 100Å was formed on the electrodes of the pair of substrates. As a result, the occurrence of short circuits between the upper and lower electrodes, which occurred during the production of the liquid crystal cell due to the narrow substrate gap of 1.5 μm, was reduced, and the yield of the liquid crystal cell was also improved. Further, in this example, an antiferroelectric liquid crystal material was used as the liquid crystal material used. Other configurations are the same as those in the first embodiment.

FIG. 5 shows a driving method of the liquid crystal cell portion of the television receiver of the present embodiment and a state of optical response to the driving. The optical shutter portion was driven by the same driving method as in Example 1. The optical amplification cell requires a voltage signal with a large absolute value and a voltage signal with a small absolute value. For example, ± 20V and ± 2V. Electrode 1
20V is applied between 7 and 22. Since the conductivity of the portion of the photoconductive film 18 irradiated with light changes, a voltage is applied to the next antiferroelectric liquid crystal material. In this way, the same image as the image of the light applied to the photoconductive film 18 is formed in the light amplification cell, that is, the image emitted by the display 1 is formed on the light amplification cell 2.

In this way, blue, red, and green images are sequentially displayed on the light amplifying cell, and this may be repeated to perform color display. Further, the liquid crystal of the light amplifying cell continues to hold the applied signal until the signal voltage level of the period T1 shown in FIG. 5 is applied. When the signal voltage level of this period T1 is applied between the electrodes 17 and 22, a low voltage of this level is applied to the antiferroelectric liquid crystal, and the display becomes black (dark). The low voltage of this level may be zero level, but when changing the signal level from a positive voltage to a negative voltage as shown in FIG. 5, if the level is set to a slightly negative small value, the response of the liquid crystal during the period T1. The time can be shortened. Similarly, when changing the signal level from a negative voltage to a positive voltage, the response time can be shortened by adding a slightly positive voltage.

In addition to the above-mentioned method, as a method of making the display of the light amplifying cell entirely black (dark) or white (bright), the period T1
The same result can be obtained by irradiating the entire surface of the photoconductive film 18 with light emitted from the entire surface of the display 1 while applying the signal of 1. The response time can be further shortened.

[0035]

As described above, an image display device such as a CRT having the structure of the present invention, a light amplification cell having a ferroelectric liquid crystal layer, three optical shutters for selecting red, green, and blue light and a light source are provided. In the television receiver that has, write the image corresponding to red, green and blue displayed on the display body to the optical amplification cell,
Red selected by the optical shutter corresponding to red, green, blue,
It was possible to obtain a color projection image by reading out the image corresponding to each color written in the light amplification cell by the green and blue lights and synthesizing these images.

As compared with the conventional television receiver using the cathode ray tube, it is possible to obtain a projection type television receiver which is inexpensive, lightweight and compact. Further, since the projection type CRT manufactured at low cost can be used for the display body, the effect of high manufacturing efficiency can be obtained.

[Brief description of drawings]

FIG. 1 shows a structure of a television receiver of the present invention.

FIG. 2 shows a structure of a light amplification cell.

FIG. 3 shows a structure of an optical shutter.

FIG. 4 shows a drive table according to the first embodiment.

FIG. 5 shows a drive table according to a third embodiment.

[Explanation of symbols]

 1 Display 7, 8, 9 Optical Shutter 2 Optical Amplifying Cell 4, 5, 6 Dichroic Mirror 12 Projected Image 3 Halogen Lamp 17, 22 Transparent Conductive Film 18 Photoconductive Film 19 Dielectric Film 20 Light-Shielding Film 23, 30 Uniaxial Alignment Film 24, 31 Ferroelectric liquid crystal

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical indication location H04N 5/74 K 9068-5C 9/31 B 8943-5C

Claims (3)

[Claims] 1. A light-transmitting conductive film, a photoconductor that reduces resistance when light is sensed, a first light-transmitting substrate having a dielectric thin film that blocks light, a light-transmitting conductive film, and a uniaxial film. An optical amplifying section composed of a ferroelectric liquid crystal layer or an antiferroelectric liquid crystal layer sandwiched between a second light transmissive substrate having an alignment means, and one display for providing an image from the first substrate side. An image writing unit having a body, a light source and its light are separated into three colors of red, green and blue by using three dichroic mirrors, a liquid crystal optical shutter and a mirror body,
An image is formed by one display body which is selected by using them, and which is composed of an image reading unit for making light incident from the second substrate, a mirror body, and an image forming unit for projecting an image on a screen by a lens. A television receiver characterized by: 2. The display body according to claim 1, is a CRT.
Alternatively, a television receiver characterized by being a matrix-driven liquid crystal display having a light source behind it, an electroluminescence display, or a plasma display. 3. The optical shutter according to claim 1,
A television receiver characterized by being a ferroelectric liquid crystal panel, an antiferroelectric liquid crystal panel or a dispersion type liquid crystal panel.