JPH05232437A - Television image receiver and its image display method - Google Patents

Abstract

PURPOSE:To obtain a full-color projection type television which is rewritable in real time and to provide a projection type television image receiver which is more inexpensive, lighter in weight, and more compact than a television image receiver which utilizes a cathode-ray tube, by using one display, three liquid crystal light shutters and three optical amplifying cells. CONSTITUTION:The projection type television image receiver which enlarges and projects the image of the display body such as a cathode-ray tube decomposes the image of the display body 1 where an original image is displayed into light beams corresponding to the primary colors, the image signals included in the light beams are converted into the light of the light source 112 which is decomposed by the primary colors while substantially amplified by optical amplifying cells 5, 6, and 7, and the light beams having the image signals of the primary colors are put together by a half-mirror to obtain a projection image 13.

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. The present invention relates to an image display device having sufficient contrast and brightness even on a large screen by substantially amplifying an original image.

[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.

In the case of a diagonal of 30 inches, the depth thereof 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, when the display surface exceeds 30 inches, the total weight easily exceeds 100 kg. It is difficult to place a heavy object exceeding 100 kg in a general household unless the place is limited, and the weight is difficult to move manually when the layout is changed. It was an obstacle to the spread to the home.

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. In addition, although many projections using TFT panels are produced, the production yield is slow to increase due to the complexity of the TFT production process, and the reality is that it has not always succeeded industrially.

In addition, since the color liquid crystal projection type television receiver uses three or more active matrix type liquid crystal display devices as display bodies for which complicated wiring patterns must be formed, the yield is further lowered. There was a fundamental problem of cost increase.

[0008]

Therefore, in the present invention, 1
The present invention provides a high-performance, light-luminance projection having three display bodies, three high-speed liquid crystal shutters, and three liquid crystal cells having a light amplification function.

A first aspect of the present invention is a television receiver having the following four components. (1) A light-transmitting conductive film, a photoconductor whose resistance decreases when it receives light, a first substrate having a dielectric thin film that blocks light, a light-transmitting conductive film, and a uniaxial orientation means. A three-body optical amplifying section composed of a ferroelectric liquid crystal layer or an antiferroelectric liquid crystal layer sandwiched between two substrates. (2) One display that provides an image and its image light
An image in which image light is incident from the first substrate side of the optical amplification section of the three bodies, which has a mirror body that distributes in three directions and an optical shutter that transmits and does not transmit the image light distributed in the three directions, respectively. Writing section. (3) In the previous period, a light source and a polarizer that allow light to enter from the second substrate side, an analyzer that receives the reflected light, and the three optical amplifying units for separating the light incident from the substrate side are paired. Image reading unit with red, green, and blue color filters. (4) The reflected light from the light amplification unit corresponding to red (R), green (G), and blue (B) that has passed through the image reading unit is set to 1
Imaging unit that creates two composite images.

An example having the above-mentioned four invention components will be shown below, and the above-mentioned four configurations will be described in detail.

FIG. 1 shows a block diagram of an embodiment of the present invention.
In FIG. 1, a display body 1 for displaying a television image is red,
It is a device that sequentially forms images corresponding to blue and green. The light is split by the mirror body 112, and is then transmitted or not transmitted by the three optical shutters 2, 3, 4 and then sent to the optical amplification units 5, 6, 7.

As the display 1 in this case, a CRT, a multiplex driving liquid crystal panel having a light source behind it, an electroluminescence panel, a plasma display or the like can be used. Since this display body is merely for forming an image, it does not need to be a color display, and may be black and white or two colors corresponding thereto.

As the optical shutter, a ferroelectric liquid crystal panel, an antiferroelectric liquid crystal panel, or a dispersion type liquid crystal panel is used. The image light from the display body corresponding to each of R, G, and B colors is sent to the three optical amplification units 5, 6, and 7 to become a write signal.

In the case of FIG. 1, since the color display is made by synthesizing red (R), blue (B), and green (G), it has three optical amplifiers. A larger number of light amplification units may be provided for color display, or another color may be combined.

FIG. 2 shows a schematic structure of the optical amplification units 5, 6, and 7. As shown in FIG.
A light-transmitting conductive film 20 formed thereon, and a photoconductor 21 having a property of lowering electrical resistance when irradiated with light,
A dielectric layer 22 that reflects light thereon, a first substrate that further includes a light blocking layer 23, a translucent conductive film 25 formed on a glass substrate, and a ferroelectric liquid crystal or an antiferroelectric liquid crystal. A uniaxial alignment film 26 for uniaxially aligning
In this substrate, a ferroelectric liquid crystal layer or an antiferroelectric liquid crystal 28 sandwiched between the first substrate and the second substrate.

As shown in FIG. 2, writing light 29 and reading light 30 are incident on both sides of this portion.
The reading light 30, which is each color signal of R, G, B, is generated by an appropriate light source such as a halogen lamp,
The dichroic mirrors 8, 9 and 10 shown in FIG. 1, which are color filters for splitting the light into different wavelengths, split the light and irradiate the respective light irradiation sections.

In FIG. 1, 03 is the writing light and 0
Reference numeral 1 is a reading light, and 02 is an image actually used for projection. The 02 light is the 01 light reflected by the optical amplification section 5, and the 02 light is the writing light 03.
By converting the image contained in (29 in FIG. 2), the image of the light 03 from the display body is amplified to 02
Light will be projected as an image.

In the above description, the three primary colors R
Although it is for any one color signal of (red), G (green), and B (blue), the same applies to other color signals.

In the configuration of the present invention, neither writing light nor reading light is transmitted through the optical amplification section. In FIG. 2, the light (that is, the writing signal 29) from the display body (1 in FIG. 1) which is the light having the image is the first substrate side (the glass substrate 24).
The incident light from the side reduces the resistance of the photoconductor 21 in a portion where a large amount of light having an image is irradiated. As a result, only that part of the liquid crystal is switched, and the writing light 2
The same image as that included in 9 is displayed on the liquid crystal layer 2 of the optical amplification unit.
8 can occur.

Further, since the liquid crystal layer 28 uses the ferroelectric liquid crystal or the anti-ferroelectric liquid crystal, the image has a remarkable feature that it is held not only when writing but also when not writing. Since it has the effect of being able to hold this image, it is possible to obtain the same effect as using a plurality of display bodies at the same time, although one display body is used. For example, when an attempt is made to display a color image using a single display, conventionally, three images corresponding to R, G, and B are sequentially displayed to form a color image using the afterimage phenomenon. However, when a ferroelectric liquid crystal having an image memory property as in the configuration of the present invention is used, the previous image is retained,
The R, G, and B images are combined at the same time. The intensity of the writing light is 0.5 to 5.0 mW / cm.
^{Is 2} .

Read light 30 is applied to the image of the liquid crystal layer 28 formed by the write signal 29 having this image.
By irradiating with, the reflected light reflected according to the alignment direction of the liquid crystal is obtained. Then, by passing through the deflecting plate, reflected light having the same image as the image written on the liquid crystal 28 by the display body can be obtained.

Then, the reflected lights corresponding to R, G, and B are combined by the half mirror 11 and passed through the optical system 12, whereby the image light 13 can be obtained.

In this case, the display 1 for displaying the first image
The light of (Fig. 1) is not used directly but the light of the display 1 controls the read light which is another light. Therefore, the light source is appropriately selected and the intensity of the light of the three primary colors which is the read light is selected. However, if the amount of light is sufficient, an image having extremely high brightness can be obtained.

In the structure of the present invention, the reason why the light amplification section is named is that the light quantity projected is much larger than the light quantity of the display unit of the writing section, and the light amplification is substantially achieved. It is based on being.

According to a second aspect of the present invention, image writing light corresponding to red, blue and green generated from one display member is switched by a light switching shutter to irradiate one surface of the liquid crystal layer to write the image. The process of generating a ferroelectric liquid crystal layer or an antiferroelectric liquid crystal layer having the same image as light, and red from the other surface of the ferroelectric liquid phase layer or the antiferroelectric liquid crystal layer,
By irradiating the image reading light corresponding to blue and green, the process of generating the reflected image light and the red,
This is an image display method for a television receiver characterized by displaying images by combining reflected image lights corresponding to blue and green.

The present invention applies to red, green, blue or R, G,
By irradiating light having an image corresponding to B to one surface of the liquid crystal layer corresponding to each of R, G, and B with an optical shutter at appropriate times, an image corresponding to each of R, G, and B is generated in the liquid crystal layer. By further irradiating the other surface of this liquid crystal layer with the light split into R, G, and B,
A reflected image light having an image corresponding to R, G, B generated on the liquid crystal layer is obtained, and the reflected image light corresponding to R, G, B is combined to obtain a color projection image. ..

As the liquid crystal layer, it is preferable to use a ferroelectric liquid crystal (FLC) or an antiferroelectric liquid crystal having a high-speed response and a memory property, but it is also possible to use another liquid crystal. The configuration of the present invention will be described in detail below with reference to examples.

[0028]

【Example】

[Example 1] An example using the present invention will be described.
The structure of the apparatus in this embodiment is as shown in FIG.

As the image display body, a CR having normal light intensity is used.
T was used. This image is decomposed into three directions by the half mirror 112, passed through optical shutters 2, 3 and 4, and the shutters are turned on and off to sequentially amplify the image light corresponding to red, blue and green. Proceed to cells 5, 6 and 7 to form an image in the amplification cell

First, the structure of the optical shutters 2, 3 and 4 will be described. A panel using a ferroelectric liquid crystal is used for the optical shutter. FIG. 3 shows its configuration diagram. The ferroelectric liquid crystal panel can obtain a high-speed response of about 100 μsec and is optimal as an optical shutter. Of course, other optical shutters such as optical shutters using dispersed liquid crystal may be used here.

The method of manufacturing this optical shutter will be described below. In FIG. 3, 500 to 2000 liters of ITO 32, which is a transparent conductive film, was formed on a transparent glass substrate 31 by a sputtering device. Then, apply polyimide 33 by spinner or offset printing method,
It was baked at 280 ° C. As polyimide, L manufactured by Hitachi Chemical
Q5200 was used. Then rub it with a roll of cotton velvet and then 1.6 to 1.8μ
It was fixed to the other substrate via an epoxy resin at an interval of m. Next, the ferroelectric liquid crystal 34 containing the phenylpyrimidine skeleton was kept at a temperature of about 100 ° C. and injected by the vacuum method.
After that, polarizing plates 35 ^, 35 were attached to form a cell for an optical 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.

Next, the structure of the optical amplification section shown by 5, 6, and 7 in FIG. 1 will be described with reference to FIG. As a substrate on the optical writing side, ITO 20 which is a light-transmissive conductive film was formed on a glass substrate 24 which was a light-transmissive substrate by the same method as in the previous period. The film thickness is 500 to 2000Å. next,
Then, bismuth silicon oxide is used as a photoconductor layer 21 by sputtering or vapor deposition from 100 to 3000.
A film was formed to a thickness of 0Å. In this case, amorphous silicon may be used as the photoconductor layer. This photoconductor layer has a function of lowering the resistance by 3 to 4 digits by light irradiation. A dielectric layer 22 for reflecting light was formed thereon. As the film forming method, a film having a thickness of 1000 to 4000 Å was formed by vapor deposition or sputtering.

On the other hand, as the substrate on the light reading side, a substrate on which ITO25 was formed on a glass substrate 27 in the same manner as ITO20, and then a polyimide film as an alignment film 26 was formed and subjected to uniaxial alignment treatment was used. .. The substrate on the optical reading side and the substrate on the optical writing side in the previous period 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 28 having an optically active group in the liquid crystal molecule was injected by the vacuum method to complete a light amplification cell. With this cell thickness, the bright transmitted color of the liquid crystal is white. The optical amplification cell was constructed as described above.

In FIG. 1, this optical amplification unit has a 200
Light from the mW / cm ² high-pressure halogen lamp 112 is split into R, G, and B by the three dichroic mirrors 8, 9, and 10 and is irradiated.

The light incident through the polarizer 16 in the light amplifying portion is reflected according to the ferroelectric liquid crystal image of the light amplifying portion (light amplifying cell) formed by the image of the display 1 and passes through the analyzer 19. Focused on the imaging mirror or optics 12. Then, the projected image 13 is projected on the wall or the screen. The contrast ratio at that time is 1
It is from 00 to 200.

Polarizer and optical inspection are 16 and 1 in FIG.
It refers to a set of polarizing plates that are formed in the form of 90 ° shifts. In the present embodiment, these polarizing plates are configured so as to be offset by 90 degrees from each other, but they may be configured in other relationships. Further, 18 and 15, 17 and 14 are also a polarizer and an analyzer having the same configuration as described above.

An example of drive waveforms and cell responses for actually operating the television receiver in this embodiment will be described with reference to FIG. R, G, and B in FIG. 4 correspond to the light separated by any of the dichroic mirrors 8, 9, and 10 in FIG.

As shown in FIG. 4, first, the optical shutter corresponding to red (R) is in a transmissive state at a voltage of 10 V for 5 milliseconds, and is in a non-transmissive state for the next 10 milliseconds. In the meantime, green (G) and blue (B) are sequentially transmitted (that is, with a delay of 5 msec as shown in FIG. 4). At the same time, the CRT image corresponding to each color is sent to the amplification cell. This makes it possible to draw 60 screens of red (R), green (G), and blue (B) per second.

Next, driving 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, the electric field is applied to the liquid crystal only in that portion, and the liquid crystal responds.

The time required for the liquid crystal to respond in the light amplification cell is as shown in FIG. 4 because of the use of the ferroelectric liquid crystal.
Very fast, about 100 μs. 5 optical shutters
Even if a dark state occurs after m seconds, the image does not disappear, and the image is held until 15 m seconds after the next optical writing image arrives. Therefore, even if the optical shutter is in the transmissive state for 5 msec and the image of the amplification cell is rewritten, the rewriting time is very fast and the image is held, so that each amplification cell is almost always You will have an image. Therefore, the image by the projection light is always drawn by the image of three colors, and a very bright projection image is captured.

For example, when a light amplification cell using a nematic liquid crystal or a dispersion type liquid crystal is used, the projected image is always drawn in any one color because these cells have no memory property. In other words, by observing momentary continuous images, colors are combined on the viewer's interval. However, the configuration of the present invention is characterized in that the colors are combined by combining the three primary colors that are always performed at the same time.

[Embodiment 2] This embodiment is an example in which a TFT (thin film transistor) is used as a pixel driving element of the display 1 in FIG. The liquid crystal cell in this embodiment is a liquid crystal cell having 320 × 220 pixels and not having a color filter. In this case, since it is not necessary to provide a color filter inside the cell, the fractional distillation for producing the cell is relatively high. The TFT is manufactured by using amorphous silicon or polysilicon for the semiconductor layer. If a backlight is provided behind this liquid crystal cell, the light intensity will be 1
Thus, a liquid crystal panel having a high contrast ratio of 5 mW / cm ² and a contrast ratio of 100: 1 can be obtained. This liquid crystal cell was placed at the display shown in FIG. 6 and the whole was driven. The projected image on the wall was a bright display with a contrast ratio of 100: 1 and a maximum brightness of 150 cd / cm ² .

Example 3 Optical amplification sections (optical amplification cells) shown by 5, 6, and 7 in FIG. 1 were similarly manufactured by the method described in Example 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.
Further, a silicon oxide film having a thickness of about 100 Å was formed on the electrodes of the pair of substrates. As a result, the substrate spacing is 1.5 μm
Due to the narrow width, the occurrence of short circuits between the upper and lower electrodes, which occurred during the production of the liquid crystal cell, was reduced, and the yield of the liquid crystal cell was improved. Further, in this example, an antiferroelectric liquid crystal material was used as the liquid crystal material used. Other configurations are in the first embodiment.
It is similar to the case of.

FIG. 5 shows the driving method of the liquid crystal cell portion of the television receiver of the present embodiment and the optical response to the driving method. The optical shutter portion was driven by the same driving method as in Example 1. For example, a voltage of ± 20 V is applied between the electrodes 20 and 25 to the light amplification cell. Since the conductivity changes in the portion where the photoconductor 21 is irradiated with light, a voltage is applied to the antiferroelectric liquid crystal material existing next. In this way, the same image as the image of the light with which the photoconductor 21 is irradiated is formed in the light amplification cell, that is, the image emitted by the display body 1 is an image of three lights of red, green, and blue. It is formed on the light amplification cells 5, 6, 7.

Each of the three light images is continuously held until the signal voltage level of the period T1 shown in FIG. 5 is applied to the light amplification cell. When the signal voltage level during this period T1 is applied between the electrodes 20 and 25, a low voltage of this level is applied to the antiferroelectric liquid crystal, and the display becomes black (dark). This low level voltage may be zero level,
As shown in FIG. 5, when changing the signal level from a positive voltage to a negative voltage, if the level is set to a slightly small negative value, the response time of the liquid crystal in the period T1 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 method, as a method for displaying the entire light amplification cell in black (dark) or white (bright), the period T1
The same result can be obtained by irradiating the entire surface of the photoconductor 21 with light emitted from the display 1 while applying the signal of 1. The response time can be further shortened.

[0047]

As described above, by using the one display member, the three liquid crystal optical shutters, and the three optical amplification cells, which are the constitutions of the present invention, full-color projection type real-time rewriting is possible. It was possible to obtain a possible television, and it was possible to realize a projection type television receiver that is cheaper, lighter and more compact than a television receiver that conventionally uses a cathode ray tube.

In particular, since the liquid crystal optical shutter and the optical amplification cell do not need to be patterned at all, the problem of yield which has been a problem in the past can be solved, and a projection type CRT manufactured at a low cost can be displayed. It has the feature that it can be used for. Further, by using a ferroelectric liquid crystal or an antiferroelectric liquid crystal having a high-speed response and a memory property for the optical shutter and the optical amplification cell, it was possible to obtain a fine image having high brightness.

[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]

 DESCRIPTION OF SYMBOLS 1 Display body 11 Mirror body 113 Mirror 2, 3, 4 Optical shutter 5, 6, 7 Optical amplification cell 8, 9, 10 Dichroic mirror 13 Projection image 112 Halogen lamp 20, 25 Transparent conductive film 21 Photoconductive film 22 Dielectric film 23 Light-shielding film 26, 33 Uniaxial alignment film

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 (4)

[Claims] 1. A translucent conductive film, a photoconductor whose resistance decreases when it receives light, a first substrate having a dielectric thin film that blocks light, a translucent conductive film, and a uniaxial orientation means. Optical amplifying section composed of a ferroelectric liquid crystal layer or an anti-ferroelectric liquid crystal layer sandwiched between a second substrate having an optical element, one display body for providing an image, and the image light in three directions. An image writing unit having a distributing mirror body and an optical shutter for transmitting and non-transmitting the image light distributed in the three directions, and injecting the image light from the first substrate side of the optical amplifying unit of the three bodies. An image reading unit having a red light source, a light source for injecting light from the second substrate side, and a red, green, and blue color filter unit paired with the three light amplification units for receiving the reflected light; Image forming unit that converts reflected light from the optical amplification unit that has passed through the reading unit into one combined image And a television receiver characterized by having. 2. 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. 3. An image writing light corresponding to red, blue, and green generated from one display body is switched by a light switching shutter to irradiate one surface of the liquid crystal layer, and the same image as the image writing light is formed. The process of forming the ferroelectric liquid crystal layer having the above and irradiating the image reading light corresponding to red, blue, and green from the other surface of the ferroelectric liquid phase layer to generate the reflected image light. An image display method for a television receiver, characterized in that an image is displayed by synthesizing a process and reflected image lights corresponding to the red, blue and green. 4. The optical shutter according to claim 3,
A television receiver characterized by being a ferroelectric liquid crystal panel, an antiferroelectric liquid crystal panel or a dispersion type liquid crystal panel.