JPH05313118A - Image display device - Google Patents

Abstract

PURPOSE:To structure a system which is visually nondefective by using a defective liquid crystal light valve module for a projection type image display device which uses an electrooptic modulating element such as an liquid crystal light valve. CONSTITUTION:In the display device which projects the light output from the electrooptic modulator through a projection optical system, at least one electrooptic modulating element 113 for defect correction which has nearly the same function is installed in addition to necessary irreducible electrooptic modulating elements 109, 111, and 112 and their light outputs can be combined and guided in the optical system 117. The added electrooptic modulating element 113 is so driven as to compensate defects of the electrooptic modulating elements 109, 111, and 112.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device,
In particular, the present invention relates to a technique for improving the performance of a projection type image display device using an electro-optical modulator such as a liquid crystal light valve.

[0002]

2. Description of the Related Art In recent years, an image display device using a liquid crystal material, that is, a liquid crystal display is more flexible than a CRT (cathode ray tube), which is a typical conventional display, and therefore has been applied in various fields. Has been actively studied. However, to date, liquid crystal displays are not powerful enough to completely replace CRTs. There are various possible reasons for this, but typical ones are the problem of display quality, the problem of manufacturing cost, and the problem of defective display due to defects.

Of these, the problem of display quality is largely due to the performance of liquid crystal materials, driving elements, etc., and the improvement of these performances is the solution. Further, the problem of manufacturing cost and the problem of display failure due to a defect have a common cause, and the occurrence of the defect is the fundamental cause in both cases.

FIG. 5 shows an example of the configuration of a conventional color type projection type liquid crystal display using a liquid crystal light valve. In FIG. 5, a light beam emitted from a metal halide lamp 501, which is a light source, passes through an ultraviolet ray cut filter 502 and an infrared ray cut filter 503 to visually remove excess components, and then a total reflection mirror 50.
The optical path can be bent at 4. The total reflection mirror 504 is installed only to make the configuration of the present optical system compact, and can be omitted if the position of the light source is changed. The light beam reflected by the total reflection mirror 504 goes to the dichroic mirror 505 for separating the red light component. Dichroic mirror 505 for separating red light component
Reflects only the red component of the incident light component, the reflected red light component passes through the total reflection mirror 506 to the red component modulation light valve 507, and the remaining component light component is green. It goes to the dichroic mirror 508 for separating the light components. The dichroic mirror 508 for separating the green light component reflects only the green component out of the components of the incident light beam, and the reflected green light component is left in the modulation light valve 509 for the green component. Rays of
That is, the blue component light goes to the blue component modulating light valve 510.

The light beams thus separated and modulated are recombined into one optical path by the following paths.

The blue component modulated light modulated by the blue component modulating light valve 510 is reflected by the total reflection mirror 511, transmitted through the semi-transparent mirror 512, and projected by the projection lens 513.
Head to. Also, the light valve 509 for modulating the green component
The modulated light of the green component modulated by is reflected by the semi-transparent mirror 514 and the semi-transparent mirror 512, and travels toward the projection lens 513. Further, the red component modulated light modulated by the red component modulating light valve 507 passes through the semi-transparent mirror 514, is reflected by the semi-transparent mirror 512, and travels toward the projection lens 513.

In this way, the light beams separated and modulated for each component are finally put together in one optical path, and can be projected on a screen or the like. A condenser lens 515 is installed on the light incident side of all the liquid crystal light valves in order to improve the light utilization efficiency.
The line indicated by the alternate long and short dash line in the drawing indicates the optical axis of the present optical system.

[0008]

In the case of a display, including the cases as in the above-mentioned conventional example, if even one place is defective in one display area, the value as a product is very high. Will fall. However, since the liquid crystal display has a very long manufacturing process and the element area of a cutout unit is significantly larger than that of an integrated circuit, the frequency of occurrence of this defect is very high. However, in the past, the defects could only be repaired by a technique that required a great deal of manpower. For example, a typical method is to connect terminals for repair, which are installed in advance on both ends of a broken wire, by using a method such as soldering or wire bonding.

Therefore, an object of the present invention is to obtain a visually defect-free display image by using a defective liquid crystal light valve module without using the conventional manual defect repair work of the liquid crystal display. Image display device.

[0010]

In order to achieve the above object, the present invention provides an image display device for projecting light output from one or more electro-optical modulators through a projection optical system.
At least one electro-optical modulation element required at least, at least one electro-optical modulation element having a function substantially equivalent to the electro-optical modulation element for defect correction, and a display defect of the minimum required electro-optical modulation element In accordance with the above, the control signal of the minimum required electro-optical modulation element and the added electro-optical modulation element for defect correction is modulated, and only one of the optical outputs of both is transmitted to the projection optical system. It is characterized by comprising a driving means to be introduced.

Further, according to one aspect of the present invention, an optical filter for correcting the display defect is provided on the surface of the electro-optical modulator for defect correction.

[0012]

In the image display device of the present invention, a defective liquid crystal light valve is used, for example, in the case of a color system, R
-It is configured so that one system for G / B can be used as one system, and one additional liquid crystal light valve is driven to compensate for the defects of the other R, G, and B light valves. Therefore, it is possible to construct a liquid crystal light valve system that is visually defect-free by using a liquid crystal light valve including defects. That is, it becomes possible to manufacture a useful product as a product by using the liquid crystal light valve that has been excluded as a defective product on the manufacturing line at present.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows the construction of an optical system of a color type projection type liquid crystal display using a liquid crystal light valve according to an embodiment of the present invention. In FIG. 1, a light beam emitted from a metal halide lamp 101, which is a light source, is an ultraviolet cut filter 102 and an infrared cut filter 1.
The optical path is bent by the total reflection mirror 104 after the excess component is visually removed via 03. The total reflection mirror 104 is installed only to make the configuration of the present optical system compact, and can be omitted if the position of the light source 101 is changed.

The path of the light beam reflected by the total reflection mirror 104 is separated into two directions by the semitransparent mirror 105. One light ray goes to the dichroic mirror 106 for separating the red light component, and the other light ray goes to the total reflection mirror 107.

The dichroic mirror 106 for separating the red light component reflects only the red component of the incident light ray component, and the reflected red light component passes through the total reflection mirror 108 and becomes the red component. The light beam of the remaining component goes to the modulation light valve 109, and goes to the dichroic mirror 110 for separating the green light component.

The dichroic mirror 110 for separating the green light component reflects only the green component of the incident light components, and the reflected green light component is directed to the green component modulating light valve 111. The light beam of the remaining component, that is, the light of the blue component goes to the light valve 112 for modulating the blue component. Further, the light rays reflected by the total reflection mirror 107 are introduced into the added liquid crystal light valve 113.

The light beams thus separated and modulated are recombined into one optical path by the following paths.

The blue component modulated light modulated by the blue component modulating light valve 112 is reflected by the total reflection mirror 114, passes through the semi-transparent mirror 115 and the semi-transparent mirror 116, and goes to the projection lens 117. The modulated light of the green component, which is modulated by the light valve 111 for modulating the green component, is reflected by the semi-transparent mirror 118 and the semi-transparent mirror 115, passes through the semi-transparent mirror 116, and travels toward the projection lens 117. Further, the red component modulated light modulated by the red component modulating light valve 109 is transmitted through the semi-transparent mirror 118, and the semi-transparent mirror 1 is transmitted.
The projection lens 1 is reflected by 15 and passes through the semi-transparent mirror 116.
Head to 17. Also, an additional liquid crystal light valve 11
The modulated light modulated by 3 is reflected by the semi-transparent mirror 116,
Heading to the projection lens 117.

In this way, the light rays separated / modulated for each component and the light rays modulated by the added liquid crystal light valve 113 are finally combined into one optical path, and a screen or the like (not shown). Can be projected on. A condenser lens 119 is installed on the light incident side of all the liquid crystal light valves in order to improve the light utilization efficiency. The line indicated by the alternate long and short dash line in the drawing indicates the optical axis of the present optical system. In addition, the arrow in the drawing indicates the traveling direction of the light beam.

FIG. 2 shows an example of installation of an optical filter on the surface of the added liquid crystal light valve 113 of FIG. 1 according to an embodiment of the present invention. In FIG. 2, on the surface of the added liquid crystal light valve 113, an optical filter 202 that transmits only a red component (R), optical filters 203 and 204 that transmits only a green component (G), and only a blue component (B) are provided. A transparent optical filter 205 is attached. These filters are installed in a shape including a defect of the liquid crystal light valve for modulating the corresponding color component.

FIG. 3 shows a control signal for switching the minimum required electro-optical element and the added electro-optical modulation element according to one embodiment of the present invention, and corresponds to the optical filter shown in FIG. An example of what is configured is shown. The numbers shown in FIG. 3 are symbols showing the following.

0: No additional liquid crystal light valve is used.

1: The added liquid crystal light valve is used as a red modulation element.

2: The expanded liquid crystal light valve is used as a green modulation element.

3: The additional liquid crystal light valve is used as a blue modulation element.

In the actual device configuration, the numbers shown are
It is digital signal information stored in a 2-bit memory array (not shown). Using this signal, the display signal is switched, and the modulated light outputs of the originally existing liquid crystal light valves 109, 111, and 112 for modulation and the added liquid crystal light valve 113 are combined so that there is no visual effect. Build a defective liquid crystal light valve system.
That is, when the symbol shown in the figure is 0, the input image signal is used as it is for the liquid crystal light valve 10 for modulation of each color.
The black signal is input to the expanded liquid crystal light valve 113. On the other hand, when the symbol shown in the figure is 1, the input image signal is input to the liquid crystal light valves 111 and 112 for modulating green and blue, and the black signal is input to the liquid crystal light valve 109 for modulating red.
A red image signal is input to the added liquid crystal light valve 113. The same applies when the symbols shown are 2 and 3. Here, the black signal is an input voltage value at which no optical output is produced.

However, according to the above convention, if two or more liquid crystal light valves are defective at the same location, they cannot be dealt with. However, in practice, it is possible to easily know which position of the liquid crystal light valve to be used is defective in the inspection process before assembling (assembling) the constituent elements. Is extremely easy.

FIG. 4 shows an example of a circuit configuration for controlling switching between the minimum required electro-optical element and the added electro-optical modulation element according to an embodiment of the present invention. In this example, the display is binary, and the black signal has a low level,
It is a circuit configuration example when a high level is used as a light emission signal.

The switching control signal obtained from the 2-bit memory array 401 storing the switching control signal as shown in FIG. 3 is analyzed by the decoder 402.
This decoder 402 interprets 2-bit information,
It has a function of simply outputting which value from 0 to 3. Here, it is the address signal provided via the clock signal that determines which data of the 2-bit memory array 401 that stores the switching control signal is used as the control signal. The control signal obtained by the decoder 402 is interpreted by the logic circuit group 403 for realizing the function described in FIG. 3, and the red display liquid crystal light valve 109, the green display liquid crystal light valve 111, and the blue display liquid crystal light. The image signals of the respective colors given to the bulb 112 and the added liquid crystal light bulb 113 are distributed.

[0031]

As described above, according to the present invention,
In a display device for projecting an optical output from an electro-optical modulator through an optical system, at least one electro-optical modulator for defect correction, which has at least one and substantially the same function in addition to the minimum required electro-optical modulator. And has a structure that allows the combination of their optical outputs to be introduced into the projection optical system, and by installing an optical filter on the surface of the expanded electro-optical modulator, The same application can be applied to the image, and the control signal of the electro-optical element that is the minimum required according to the defect of the electro-optical element and the control signal of the added electro-optical modulation element are modulated, and either of the optical outputs of both is output. Since only one of them is introduced into the projection optical system, visually the same display characteristics as in the case of combining a normal defect-free panel can be obtained. That is,
According to the present invention, it is possible to obtain an effect that a liquid crystal light valve can be used to construct a system that is visually defect-free even if a defective liquid crystal light valve module is used.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an optical system of a color type projection liquid crystal display using a liquid crystal light valve according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of installing an optical filter on a surface of the added liquid crystal light valve 113 of FIG. 1 according to an embodiment of the present invention.

FIG. 3 shows a control signal for switching between the minimum required electro-optical element and the added electro-optical modulation element according to one embodiment of the present invention, which is configured to correspond to the optical filter shown in FIG. It is a figure which shows an example.

FIG. 4 is a diagram showing an example of a circuit configuration for performing switching control of a minimum required electro-optical element and an added electro-optical modulation element according to an embodiment of the present invention.

FIG. 5 is a diagram showing an example of the configuration of a conventional color type projection type liquid crystal display using a liquid crystal light valve.

[Explanation of symbols]

101 metal halide lamp 102 ultraviolet cut filter 103 infrared cut filter 104 total reflection mirror 105 semi-transparent mirror 106 dichroic mirror for separating red light component 107 total reflection mirror 108 total reflection mirror 109 light valve for modulation of red component 110 green light component Separation dichroic mirror 111 Green component modulation light valve 112 Blue component modulation light valve 113 Added liquid crystal light valve 114 Total reflection mirror 115 Semi-transparent mirror 116 Semi-transparent mirror 117 Projection lens 118 Semi-transparent mirror 119 Condenser lens 202 Red Optical filters 203, 204 that transmit only the component Optical filters that transmit only the green component 205 Optical filter 401 that transmits only the blue component 401 Store a switching control signal Bit memory array 402 decoder 403 logic circuits

Claims (2)

[Claims] 1. In an image display device for projecting a light output from one or more electro-optical modulation elements via a projection optical system, at least one or more electro-optical modulation elements which are required at least, and the electro-optical modulation elements are almost At least one defect-correcting electro-optical modulation element having an equivalent function, and the minimum necessary electro-optical modulation element and the defect correction added in accordance with the minimum display defect of the electro-optical modulation element. For controlling the control signal of the electro-optical modulator for use so that only one of the optical outputs of the both is introduced into the projection optical system. .. 2. The image display device according to claim 1, wherein an optical filter for correcting the display defect is provided on the surface of the defect-correcting electro-optical modulator.