JP2004085645A - Holding device for reflective liquid crystal display panel, optical unit using reflective liquid crystal display panel, projection display optical system, and projection image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems of a lowering in contrast and the occurrence of brightness in a reflective liquid crystal display panel due to warpage caused by difference in thermal expansion coefficients between a glass substrate and a silicon substrate. <P>SOLUTION: A holding device for the reflective liquid crystal display panel LCD comprising a liquid crystal sealed in between the glass substrate 4 and the semiconductor substrate 2 is constructed by using a holding member 1 with a flat surface part 1b and and a pressurizing member 7 to press one substrate out of the glass substrate and the semiconductor substrate to the side of the other substrate so as to press the other substrate to the flat surface part of the holding member. Thereby the warpage of the reflective liquid crystal display panel caused by difference in thermal expansion coefficients between the glass substrate and the semiconductor substrate is corrected and the reflective liquid crystal display panel is flattened. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reflection type liquid crystal display panel holding device, a projection type display optical system using the same, and a projection type image display device.
[0002]
[Prior art]
2. Description of the Related Art In recent years, a projection type image display device using a liquid crystal display panel has become widespread. Some projection image display devices use a reflection type liquid crystal display panel.
[0003]
The reflective liquid crystal display panel is generally called LCOS, and can reduce the pixel pitch and achieve a high aperture ratio as compared with the transmissive liquid crystal display panel. It has the feature that a fine image and a smooth image can be displayed with a high aperture ratio.
[0004]
Such a reflective liquid crystal display panel has a structure in which liquid crystal is filled between a silicon substrate provided with a transistor for modulating each pixel, a pixel electrode and a reflective layer, and a glass substrate provided with a counter electrode. have.
[0005]
The specific structure of the reflection type liquid crystal display panel is proposed in, for example, JP-A-8-334770 and JP-A-7-72491.
[0006]
In the structure of the reflection type liquid crystal display panel disclosed in Japanese Patent Application Laid-Open No. 8-334770, a gap is formed between the glass substrate and the silicon substrate by providing a spacer on the outer peripheral portion of the liquid crystal display panel, and the liquid crystal is formed in the gap. Is to be sealed.
[0007]
Further, the structure of the reflection type liquid crystal display panel proposed in Japanese Patent Application Laid-Open No. 7-72491 is such that a spacer is provided for each pixel of the liquid crystal display panel to form a gap between the glass substrate and the silicon substrate. The part is sealed to seal the liquid crystal in the gap.
[0008]
Further, as a technique for forming a gap between substrates in a liquid crystal display panel, a method of spraying so-called bead spacers at a predetermined density in the gap is known.
[0009]
On the other hand, a structure for holding a reflective liquid crystal display panel is proposed in, for example, Japanese Patent Application Laid-Open No. Hei 10-91102. In the holding structure proposed in Japanese Patent Application Laid-Open No. Hei 10-91102, a glass substrate is bonded and fixed to a holder so that no stress is applied to the liquid crystal display panel even when an external force is applied to the holder.
[0010]
Further, Japanese Patent Application Laid-Open No. Hei 10-91102 proposes, as a conventional technique, an example in which a reflective liquid crystal display panel is bonded and fixed to a holder.
[0011]
[Problems to be solved by the invention]
By the way, in a reflection type liquid crystal display panel combining a glass substrate and a silicon substrate, and a reflection type liquid crystal display panel proposed in Japanese Patent Application Laid-Open No. 8-314770, when a glass substrate and a silicon substrate are bonded and sealed, about 160 ° is required. However, since the respective substrates have different coefficients of linear expansion (coefficients of thermal expansion), the amounts of strain at the commonly used temperature of 20 ° C. to 60 ° C. are different from each other, as shown in FIG. In addition, the reflective liquid crystal display panel warps, the cell gap becomes non-uniform, and a stress is generated in the glass substrate, and the polarization direction of light transmitted through the glass substrate is disturbed by the influence of photoelasticity. Therefore, the contrast of light from the reflection type liquid crystal display panel is reduced, and brightness unevenness occurs.
[0012]
Further, when a spacer for securing a gap for each pixel is provided as in a reflection type liquid crystal display panel proposed in Japanese Patent Application Laid-Open No. 7-72491, the above-mentioned effects of non-uniform cell gap and photoelasticity are reduced. However, since the pixel spacing of a reflection type liquid crystal display panel used in a projection type image display device is 8 μm to 15 μm, illumination light is diffracted by a spacer provided for each pixel, and a part of the pupil of a projection lens is used. Going outside, the light use efficiency decreases. Also, the diffracted light reflected by a part of the color separation optical system is mixed and the polarization is disturbed, and the diffracted light remains in the pupil of the projection lens even in the black display state due to the angular characteristics of the polarization beam splitter used in the color separation optical system. There is a possibility that the light will be incident to lower the contrast.
[0013]
Further, as described above, in a reflection type liquid crystal display panel used in a projection type image projection device, since the pixels are small, when the bead spacers are scattered, the pixels in which the bead spacers are present and the pixels in which the bead spacers are not present exist. This may cause uneven brightness, which may make it impossible to display a high-quality image.
[0014]
On the other hand, even when the method of fixing a reflective liquid crystal display panel proposed in Japanese Patent Application Laid-Open No. Hei 10-91102 is used, the temperature at which the glass substrate and the silicon substrate are bonded and sealed, and the actual operating temperature, as described above. Therefore, the reflective liquid crystal display panel is adhered to the reflective liquid crystal display panel in a state in which deformation (warpage) as shown in FIG. 5 has occurred, so that it is not possible to suppress the reduction in contrast and the occurrence of uneven brightness.
[0015]
Therefore, the present invention can flatten the warp of the reflective liquid crystal display panel due to the difference in the coefficient of thermal expansion between the glass substrate and the semiconductor substrate, and provide the reflective liquid crystal display panel with high contrast characteristics and high brightness. An object of the present invention is to provide a holding device for a reflection type liquid crystal display panel, a projection type display system, and a projection type image display device which can be held in a state where the unevenness is extremely small.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a holding device for a reflection type liquid crystal display panel in which liquid crystal is sealed between a glass substrate and a semiconductor substrate, a holding member having a flat portion, and a glass substrate and a semiconductor substrate. A pressing member that presses one of the substrates toward the other substrate and presses the other substrate against the flat portion of the holding member is used.
[0017]
That is, without providing a spacer or a bead spacer for each pixel, the reflective liquid crystal display panel is warped due to a difference in the coefficient of thermal expansion between the glass substrate and the semiconductor substrate, and the reflective liquid crystal display panel is corrected. Flattening prevents a change in characteristics due to warpage of the reflective liquid crystal display panel. That is, the gap (liquid crystal) between the two substrates is made uniform, and the effect of photoelasticity is reduced by approaching a state in which no bending stress is generated in the glass substrate.
[0018]
This eliminates the effects of light diffraction by the spacers provided for each pixel and the effects of light blocking by the bead spacers, and displays images with high light use efficiency, high contrast, and uniform brightness. It can be so.
[0019]
In addition, by interposing a heat transfer member between the other layer and the flat portion of the holding member, it is possible to enhance heat dissipation.
[0020]
In addition, by providing a fixing portion for fixing the holding member to another member on an axis parallel to the panel surface through a substantially center of the reflection type liquid crystal display panel in the holding member, the reflection type liquid crystal due to a temperature change is provided. It is possible to prevent the displacement of the display panel.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1A is a cross-sectional view of a holding device for a reflective liquid crystal display panel according to an embodiment of the present invention, and FIG. 1B is a perspective view of the holding device. FIG. 1A is a sectional view taken along the line AA shown in FIG. 1B and viewed from the direction of the arrow.
[0022]
In these figures, reference numeral 1 denotes a holder (holding member), which is made, for example, by metal injection. The surface 1c of the holder 1 is provided with a rectangular concave portion 1a for holding the reflective liquid crystal display panel LCD, and the flat portion 1b is provided at a portion corresponding to the bottom surface of the concave portion 1a.
[0023]
First and second mounting arms (fixed portions) 1d and 1e are provided on both sides of the holder 1 on axes parallel to the panel screen through the center in the short side direction of the reflective liquid crystal display panel LCD. . These mounting arms 1d and 1e are used for fixing the holder 1 to a liquid crystal panel mounting plate (117 to 119 in FIG. 4) constituting an optical system of a projection type image display device described later.
[0024]
Further, the holder 1 is formed with a groove 1f connected to the recess 1a. The groove portion 1f is for passing a flexible printed circuit board FPC which is connected to the reflective liquid crystal display panel LCD accommodated in the concave portion 1a and transmits an electric signal for driving the reflective liquid crystal display panel LCD.
[0025]
The reflection type liquid crystal display panel LCD includes a silicon substrate (layer) 2, a glass substrate (layer) 4, a spacer 5 for forming a predetermined gap between the substrates 2 and 4, and sealing in the gap. And the liquid crystal 3 formed.
[0026]
The silicon substrate 2 is provided with a transistor for controlling the polarization state of each pixel and a circuit for inputting a voltage signal to be applied to the pixel from an external driving circuit via the flexible printed circuit board FPC. There are provided a reflection layer for reflecting light, an alignment film for controlling liquid crystal, and the like.
[0027]
The glass substrate 4 is provided with a counter electrode. The spacer 5 is located near the outer periphery of the silicon substrate 2 and the glass substrate 4, and the substrates 2 and 4 are bonded and fixed in a state where a gap for sealing the liquid crystal 3 is formed by the spacer 5.
[0028]
Reference numeral 7 denotes a pressing plate, which is formed, for example, by pressing a stainless steel plate into a rectangular frame shape. Inside the pressing plate 7, first to fourth spring portions 7a, 7b, 7c, 7d are formed.
[0029]
Reference numeral 8 denotes a holding plate, which is formed in a rectangular frame shape by, for example, pressing a stainless steel plate. By pressing the pressing plate 7 between the holding plate 8 and the outer portion of the concave portion 1a on the surface of the holder 1 and fixing the holding plate 8 to the holder 1 with screws 9a, 9b, 9c, 9d, the pressing plate 7 The holder in a state where the first to fourth spring portions 7a, 7b, 7c, 7d are in contact with the peripheral portion (portion outside the effective screen area) of the surface of the glass substrate 4 of the reflection type liquid crystal display panel LCD. Fixed to 1.
[0030]
Reference numeral 6 denotes a heat transfer sheet, which is disposed between the silicon substrate 2 of the reflection type liquid crystal display panel LCD and the flat portion 1b of the holder 1.
[0031]
In the reflective liquid crystal display panel LCD alone, since the temperature at which the glass substrate 4 and the silicon substrate 2 are bonded to each other is high, at a temperature of about 20 to 60 ° C. at which the reflective liquid crystal display panel LCD is assembled or used. Due to the difference (generally, A <B) between the coefficient of thermal expansion A of the glass substrate 4 and the coefficient of thermal expansion B of the silicon substrate, deformation (warpage) such that the surface of the glass substrate becomes concave as shown in FIG. ) Occurs.
[0032]
As a result, internal stress is generated in the glass substrate 2, and the polarization state of light transmitted through the glass substrate 2 is disturbed at a predetermined ratio due to the influence of photoelasticity. In addition, the gap in which the liquid crystal 3 is sealed is deformed, and the action on polarized light loses uniformity.
[0033]
When such a reflection type liquid crystal display panel LCD is fitted into the concave portion 1a of the holder 1 and the pressing plate 7 is fixed to the holder 1 with screws 9a to 9d via the pressing plate 8, the first to fourth springs of the pressing plate 7 The parts 7a to 7d push the glass substrate 4 of the reflective liquid crystal display panel LCD toward the silicon substrate 2. With this pressing force, the substantially entire surface of the silicon substrate 2 is pressed against the flat portion 1b of the holder 1 via the heat transfer sheet 6, and the reflective liquid crystal display panel LCD (the silicon substrate 2 and the glass substrate 4) is returned to a flat shape. . Thereby, the gap between the silicon substrate 2 and the glass substrate 4 becomes uniform.
[0034]
That is, the deformation force generated in the reflective liquid crystal display panel LCD due to the difference between the coefficient of thermal expansion of the glass substrate 4 and the coefficient of thermal expansion of the silicon substrate is canceled by the pressing force received from the pressing plate 7, and the reflective liquid crystal display panel LCD Is an original flat shape.
[0035]
Thus, the stress applied to the glass substrate 4 is also eliminated, and the effect of photoelasticity is reduced. Strictly speaking, a compressive stress acts on the glass substrate 4 to cause an effect of photoelasticity, but the amount is small.
[0036]
Although the spacer 5 also receives a compressive force, the value of the gap changes. However, since the thickness of the spacer 5 is as thin as 2 to 5 μm, the amount of deformation is small, and the performance of the reflective liquid crystal display panel LCD is limited by the gap. This is improved by making the glass substrate 4 uniform and reducing the influence of the photoelasticity of the glass substrate 4.
[0037]
Further, a flexible printed circuit board FPC required for electrical connection for driving the reflection type liquid crystal display panel LCD is led out of the holder 1 through a groove 1f formed in the holder 1, and is provided on the reflection type liquid crystal display panel LCD. Are connected to a driving circuit for driving the. With such a structure, it is possible to prevent a variation in the pressing force of the reflection type liquid crystal display panel LCD by the pressing plate 7 between a portion where the flexible printed circuit board FPC is led out of the holder 1 and other portions. Can be prevented.
[0038]
Next, FIGS. 2A, 2B, 3A, and 3B show how the characteristics of the reflective liquid crystal display panel LCD are changed by holding by the holding device described above. ).
[0039]
2 (a), 2 (b), 3 (a), and 3 (b) are views showing the viewing angle characteristics of the reflection type liquid crystal display panel LCD. And the azimuth angle when right above is set to 0 °, and the radial direction of the graph indicates the contrast value. The inclination angle from the normal direction of the panel screen is defined as the inclination angle, and the above figures show data of the inclination angles of 4 °, 8 °, and 12 °. This tilt angle corresponds to how much F-number is illuminated when the reflection type liquid crystal display panel LCD is used for a projection type image display device, and 12 ° generally corresponds to F2.3.
[0040]
Also, the contrast value in the figure is a method in which illumination light in a polarization state in the short side direction of the panel is incident as a light beam, and the reflected light is analyzed by a polarizing plate whose polarization direction is oriented in the long side direction of the panel. The luminance in black display and the luminance in white display are measured, and the ratio is shown as a contrast value. The azimuth was measured every 22.5 °.
[0041]
The characteristics shown in FIG. 2A are measured values of the reflection type liquid crystal display panel alone at normal temperature (about 25 ° C.). FIG. 2B is an enlarged view of the origin part of the characteristic shown in FIG. As can be seen from FIG. 2A, the highest contrast value is obtained when the tilt angle is 12 ° and the azimuth angle is 247.5 °, but the contrast value is low under other conditions. In particular, as can be seen from FIG. 2B, when the tilt angle is 4 degrees, which is a condition with a small tilt angle close to the ideal condition, the contrast value is at most about 1000: 1.
[0042]
Also, the contrast values at the azimuth angles 135 ° and 315 ° when the inclination angle is 12 ° are very low values. In the case of a reflective liquid crystal display panel, a larger tilt angle does not indicate a higher contrast, and it can be seen from this measurement result that the reflective liquid crystal display panel cannot exhibit the characteristics that it should originally exhibit.
[0043]
On the other hand, the characteristic shown in FIG. 3A is that the reflection type liquid crystal display panel is incorporated in the holder 1 of the present embodiment under the same conditions as those shown in FIGS. 7 shows characteristics when a pressing force is applied. FIG. 3B is an enlarged view of the origin part of the characteristic shown in FIG.
[0044]
As can be seen from FIG. 3A, when the tilt angle is 4 degrees, the contrast value is the highest, and when the tilt angle is 8 degrees or 12 degrees, a cross-shaped contrast characteristic is obtained. You can see that it is working.
[0045]
Further, as can be seen from FIG. 3B, when the tilt angle is 8 °, a contrast value of at least 1500: 1 is obtained, and the contrast characteristic is greatly improved as compared with the case of the reflection type liquid crystal display panel alone. I have. Further, the contrast value is improved to about 300: 1 even at the inclination angles of 12 ° and the azimuth angles of 135 ° and 315 ° where the contrast value is the lowest.
[0046]
As described above, the reflection type liquid crystal display panel LCD is held by the holding device of the present embodiment, and the warpage caused by the difference in the coefficient of thermal expansion between the substrates 2 and 4 is flattened. The characteristics can be improved.
[0047]
Next, the configuration of a projection display optical system of a projection type image display device using the reflection type liquid crystal display panel LCD held by the above-described holding device will be described with reference to FIG.
[0048]
4, reference numeral 101 denotes a light source that emits white light in a continuous spectrum, and 102 denotes a reflector that collects light in a predetermined direction. 103a is a first fly-eye lens in which rectangular lenses are arranged in a matrix, and 103b is a second fly-eye lens composed of a lens array corresponding to each lens of the first fly-eye lens 103a.
[0049]
Reference numeral 104 denotes a polarization conversion element for converting unpolarized light into predetermined polarized light, 105a a condenser lens, 105b a field lens, and 105c a mirror.
[0050]
Reference numeral 106 denotes a dichroic mirror that reflects light in the blue and red wavelength regions and transmits light in the green wavelength region. 108a and 108b convert the polarization direction of the blue light by 90 degrees, and change the polarization direction of the red light. A first color-selective phase plate and a second color-selective phase plate which are not used.
[0051]
Reference numerals 110a, 110b, and 110c denote a first polarizing beam splitter, a second polarizing beam splitter, and a third polarizing beam splitter that transmit P-polarized light and reflect S-polarized light. Thus, a color separation / synthesis optical system as a light guide optical system is configured.
[0052]
R, G, and B are a reflection type liquid crystal display panel for red, a reflection type liquid crystal display panel for green, and a reflection type liquid crystal display panel for blue, which reflect light and modulate and display an image. These reflective liquid crystal display panels R, G, B include the above-mentioned flexible printed circuit board FPC (flexible printed circuit board FPCG for green liquid crystal display panel G, flexible printed circuit board FPCR for red liquid crystal display panel R, blue liquid crystal display). A drive circuit (not shown) is connected via a flexible printed circuit board FPCB for the panel B, and an image signal from an image information supply device such as a personal computer, video, or DVD player is input to the drive circuit. The drive circuit drives the reflection type liquid crystal display panels R, G, B based on the input image signal, and displays an image corresponding to the image signal.
[0053]
111 is a liquid crystal display panel unit (optical unit), 111a is a base of the liquid crystal display panel unit 111, and 112, 113 and 114 are reflective liquid crystal display panels R, G and B for green, red and blue. This is the above-mentioned holding device for holding. The holder (1) of each holding device is made of metal.
[0054]
117 is a green panel mounting plate, 118 is a red panel mounting plate, 119 is a blue panel mounting plate, 120 is a light guide case, 121 is an exterior case, 122 is a lamp case, and 123 is a projection lens.
[0055]
Next, the optical function will be described. Light emitted from the light source 101 is collected in a predetermined direction by the reflector 102. Here, the reflector 102 has a paraboloidal shape, and light from the focal position of the paraboloid becomes a light beam parallel to the symmetry axis of the paraboloid. However, since the light source 101 is not an ideal point light source but has a finite size, the light beam to be collected contains many light components that are not parallel to the symmetry axis of the paraboloid.
[0056]
These condensed light beams enter the first fly-eye lens 103a. The first fly-eye lens 103a is configured by combining lenses having a rectangular shape and having a positive refractive power in a matrix shape, and the incident light beam is divided into a plurality of light beams corresponding to each lens, and is condensed. A plurality of light source images are formed in the form of a matrix near the polarization conversion element 104 via the second fly-eye lens 103b.
[0057]
The polarization conversion element 104 includes a polarization separation surface, a reflection surface, and a half-wave plate, and a plurality of light beams condensed in a matrix by the fly-eye lenses 103a and 103b are applied to the polarization separation surface corresponding to the column. The incident light is split into a P-polarized light component transmitted through the polarization splitting surface and an S-polarized light component reflected by the polarization splitting surface.
[0058]
The light of the S-polarized light component reflected on the polarization splitting surface is reflected on the reflecting surface and exits in the same direction as the P-polarized light component. On the other hand, the light of the P-polarized light component transmitted through the polarization separation surface is transmitted through the half-wave plate and converted into the same polarized light component as the S-polarized light component. As a result, all of the light emitted from the polarization conversion element 104 becomes light with the same polarization direction.
[0059]
The plurality of light beams that have been polarization-converted by the polarization conversion element 104 reach the condensing optical system 105 including a condenser lens 105a and a field lens 105b as divergent light beams. The mirror 105c has no refractive power.
[0060]
In the optical path from the field lens 105b to the reflective liquid crystal display panels R, G, and B, the light condensed on the reflective liquid crystal display panels R, G, and B is shifted with respect to the optical axis of the condenser optical system 105. It is almost telecentric.
[0061]
The dichroic mirror 106 and the polarizing beam splitters 110a, 110b, 110c are composed of optical thin films, and the characteristics change depending on the angle of incidence on these optical thin films. Therefore, by setting the illuminating luminous flux for the reflective liquid crystal display panels R, G, and B to be telecentric, a change in characteristics generated in the optical thin film does not occur on the reflective liquid crystal display panels R, G, and B. ing.
[0062]
The dichroic mirror 106 reflects blue (430-495 nm) and red (590-650 nm) light and transmits green (505-580 nm) light. Here, the transmittance of the S-polarized light component of the green light is set to 1% or less at 550 nm, which is the center wavelength of the green wavelength range, to prevent a decrease in the color purity of the other two color lights.
[0063]
In FIG. 4, the light that has been S-polarized light in the polarization conversion element 104 is also S-polarized light with respect to the dichroic mirror 106.
[0064]
In the light path of the green light, the light transmitted through the dichroic mirror 106 enters the first polarization beam splitter 110a as S-polarized light, is reflected by the polarization splitting surface of the first polarization beam splitter 110a, and The light passes through the / 4λ plate to reach the reflective liquid crystal display panel G for green. In the reflective liquid crystal display panel G for green, green light is image-modulated and reflected. The S-polarized component of the image-modulated green light (reflected light) is reflected again by the polarization splitting surface, returned to the light source side, and removed from the projected light. The P-polarized component of the image-modulated green light is transmitted through the polarization splitting surface and becomes projection light.
[0065]
The light transmitted through the first polarization beam splitter 110a also enters the third polarization beam splitter 110c as P-polarized light, passes through the polarization splitting surface, and reaches the projection lens 123.
[0066]
The red and blue lights reflected by the dichroic mirror 106 enter the first color-selective phase difference plate 108a. The first color-selective phase difference plate has an action of rotating the polarization direction of only blue light by 90 degrees, whereby blue light is converted into P-polarized light, and red light is converted into S-polarized light by the second polarizing beam splitter 110b. Incident. Therefore, in the second polarization beam splitter 110b, the blue light passes through the polarization splitting surface, passes through a 図 示 λ plate (not shown), and reaches the reflective liquid crystal display panel B for blue. The red light is reflected by the polarization splitting surface, passes through a ４λ plate (not shown), and reaches the reflective liquid crystal display panel R for red.
[0067]
Blue light is image-modulated and reflected by the reflective liquid crystal display panel B for blue. The P-polarized component of the image-modulated blue light (reflected light) passes through the polarization splitting surface again, returns to the light source side, and is removed from the projection light. The S-polarized light component of the image-modulated blue light is reflected by the polarization splitting surface to become projection light.
[0068]
Similarly, in the reflective liquid crystal display panel R for red, the red light is image-modulated and reflected. The S-polarized component of the image-modulated red light (reflected light) is reflected again by the polarization splitting surface, returned to the light source side, and removed from the projected light. The P-polarized light component of the image-modulated red light passes through the polarization splitting surface and becomes projection light. Thereby, the blue and red projection lights are combined into one light flux.
[0069]
The combined red and blue projection light is incident on the second color-selective phase difference plate 108b. The second color-selective phase difference plate 108b rotates only the polarization direction of the red light by 90 degrees and changes the polarization direction to the S-polarized light. The red light and the blue light, both of which become S-polarized light in this manner, enter the third polarization beam splitter 110c, and are reflected by the polarization splitting surface and are combined with the green projection light.
[0070]
The synthesized red, green, and blue projection lights are projected by a projection lens 123 onto a projection surface such as a screen. As a result, a full-color image corresponding to the original image displayed on the reflective liquid crystal display panels R, G, and B is projected and displayed.
[0071]
Although not shown in FIG. 4, the purpose of inserting a quarter-wave plate between the reflection type liquid crystal display panels R, G, B and the polarization beam splitters 110a, 110b is to project a projected image having higher contrast. To get it.
[0072]
A panel mounting plate 117 for green is adhered to the first polarizing beam splitter 110a, and the holding device 112 for the reflective liquid crystal display panel G for green is mounted on the first polarizing beam splitter 110a as shown in FIGS. 1 (a) and 1 (b). The arms 1d and 1e are fixed to the first polarizing beam splitter 110a by soldering to the green panel mounting plate 117.
[0073]
As described above, the silicon substrate of the reflective liquid crystal display panel G for green is pressed against the flat portion (1b) of the fixing device 112 for green via a sheet (or paste) having good heat conductivity. . Thereby, in the reflection type liquid crystal display panel G for green, the stress of the glass substrate is reduced and the gap is kept uniform so that the incident illumination light can be modulated with high contrast.
[0074]
In addition, since the silicon substrate of the reflective liquid crystal display panel G for green and the holder of the holding device 112 for green are thermally connected via a sheet (or paste) having good thermal conductivity, the reflection for green is performed. The heat dissipation of the liquid crystal display panel G is enhanced, and even if the reflective liquid crystal display panel G for green is illuminated with strong light, it is possible to prevent a thermal problem from occurring.
[0075]
A red panel mounting plate 118 and a blue panel mounting plate 119 are adhered to the second polarizing beam splitter 110b, and red and blue reflective liquid crystal displays are respectively attached to the fixing plates 118 and 119. The red holding device 113 and the blue holding device 114 holding the panels R and B, respectively, are fixed similarly to the green holding device 112.
[0076]
On the flat portions of the holders of the holding devices 113 and 114 for red and blue, the silicon substrates of the reflective liquid crystal display panels R and B for red and blue respectively have sheets (or pastes) with good heat conductivity. Have been pushed through. As a result, in the reflective liquid crystal display panels R and B for red and blue, the stress of the glass substrate is reduced and the gap is kept uniform so that the incident illumination light is modulated with high contrast. can do.
[0077]
In addition, the silicon substrates of the reflection liquid crystal display panels R and B for red and blue and the holders of the holding devices 113 and 114 for red and blue are thermally connected to each other via a sheet (or paste) having good heat conductivity. The connection enhances the heat dissipation of the reflective liquid crystal display panels R and B for red and blue, so that even if the reflective liquid crystal display panels R and B for red and blue are illuminated with strong light, the heat dissipation is reduced. Problems can be prevented.
[0078]
The holding devices 112, 113, 114 for green, red, and blue and the panel mounting plates 117, 118, 119 for green, red, and blue are made of metal, respectively, and three reflective liquid crystal display panels R, The positions of the corresponding pixels G and B are adjusted so that the corresponding pixels are projected on the corresponding positions on the screen, and the holding devices 112, 113, and 114 are fixed to the panel mounting plates 117, 118, and 119 by soldering or bonding. Have been.
[0079]
The light source 101 is fixed to a reflector 102, and the reflector 102 is fixed to a lamp case 122. The light guide case 120 is made of plastic, and a lamp case 122 is fixed to the light guide case 120.
[0080]
In the light guide case 120, the above-described first fly-eye lens 103a, second fly-eye lens 103b, polarization conversion element 104, condenser lens 105a, field lens 105b, and mirror 105c are fixedly positioned.
[0081]
A cover member (not shown) prevents dust from entering the light guide case 120 from the first fly-eye lens 103a to the field lens 105b. The state where the member was removed is shown.
[0082]
Further, the light guide case 120 includes a base 111a of the liquid crystal display panel unit 111, first and second positioning pins 120x and 120y provided on the light guide case 120, and a first base provided on the base 111a. And the second positioning pins 111x and 111y are fitted to each other, and are fixed by the first and second screws 140 and 141. The projection lens 123 is further fixed to the light guide case 120.
[0083]
A dichroic mirror 106 and first, second, and third polarization beam splitters 110a, 110b, and 110c are fixedly positioned on the base 111a, respectively. The first polarization beam splitter 110a has a green color. The reflective liquid crystal display panel G is positioned and fixed as described above, and the second polarizing beam splitter 110b is provided with a reflective liquid crystal display panel R for red and a reflective liquid crystal display panel B for blue. Is positioned and fixed.
[0084]
In the above embodiment, the case where the peripheral portion of the glass substrate 4 is pressed toward the silicon substrate 2 by the pressing plate 7 to press the silicon substrate 2 against the flat portion 1b of the holder 1 has been described. Accordingly, even if the glass substrate is pushed toward the glass substrate and the peripheral surface of the glass substrate is pressed against a flat portion provided in a rectangular frame shape on the holder, the warp of the reflective liquid crystal display panel can be flattened.
[0085]
【The invention's effect】
As described above, by holding the reflective liquid crystal display panel by the holding device of the present invention, the difference in the coefficient of thermal expansion between the glass substrate and the semiconductor substrate can be obtained without providing a spacer or a bead spacer for each pixel. This corrects the warpage of the reflective liquid crystal display panel due to the above, flattens the reflective liquid crystal display panel, and prevents a change in characteristics due to the warp of the reflective liquid crystal display panel. As a result, the gap (liquid crystal) between the two substrates can be made uniform, and the effect of photoelasticity can be reduced by approaching a state where bending stress does not occur in the glass substrate. Therefore, the light use efficiency of the reflective liquid crystal display panel can be improved, and the reflective liquid crystal display panel can display an image having high contrast and without uneven brightness.
[0086]
If the holding device of the present invention holds the reflective liquid crystal display panel used in the projection display optical system or the projection image display device, the display device is bright, has high contrast, and has no uneven brightness. A projection image can be obtained.
[Brief description of the drawings]
FIG. 1A is a sectional view of a main part of a reflection type liquid crystal display panel holding device according to an embodiment of the present invention, and FIG. 1B is a perspective view of the holding device.
FIG. 2A is a view showing a viewing angle-contrast characteristic when the holding device is not used, and FIG. 2B is an enlarged view of a central portion of FIG. 2A.
FIG. 3A is a view showing a viewing angle-contrast characteristic when the holding device is used, and FIG. 3B is an enlarged view of a central portion of FIG. 3A.
FIG. 4 is an explanatory diagram of a projection type image display device using the holding device.
FIG. 5 is an explanatory diagram showing warpage of a reflective liquid crystal display panel.
[Explanation of symbols]
1 Holder
1b Flat part
1f groove
2 Silicon substrate
3 liquid crystal
4 Glass substrate
5 Spacer
6 Heat transfer sheet
7 Press plate
8 Holding plate
9a, 9b, 9c, 9d Screw
FPC Flexible Printed Circuit Board
101 light source
102 reflector
103a, 103b Fly eye lens
104 polarization conversion element,
105a condenser lens
105b field lens
105c mirror
106 dichroic mirror
108a, 108b Color-selective phase difference plate
110a, 110b, 110c Polarizing beam splitter
R, G, B reflective liquid crystal display panel
111 LCD panel unit
111a base
112, 113, 114 holding device
117, 118, 119 Panel mounting plate
120 Light guide case
121 outer case
122 lamp case
123 Projection lens
FPCG, FPCR, FPCB Flexible printed circuit board

Claims (10)

A reflection type liquid crystal display panel holding device in which liquid crystal is sealed between a glass substrate and a semiconductor substrate,
A holding member having a flat portion,
A reflection type liquid crystal display panel comprising: a pressing member that presses one of the glass substrate and the semiconductor substrate toward the other substrate and presses the other substrate against a flat portion of the holding member. Holding device. 2. The pressing force of the pressing member has a magnitude to flatten warpage of the reflective liquid crystal display panel caused by a difference in thermal expansion coefficient between the glass substrate and the semiconductor substrate. Of a reflective liquid crystal display panel. 3. The holding device according to claim 1, wherein the one substrate is a glass substrate, and the other substrate is a semiconductor substrate. 4. 4. The holding device according to claim 3, wherein the pressing member presses a peripheral portion of the glass substrate, and substantially the entire surface of the semiconductor substrate is pressed against a flat portion of the holding member. . 4. The holding device for a reflection type liquid crystal display panel according to claim 3, wherein a heat transfer member is interposed between the semiconductor substrate and a plane portion of the holding member. The reflection type liquid crystal display according to any one of claims 1 to 5, wherein a groove portion for passing a flexible wiring board connected to the reflection type liquid crystal display panel is formed in the holding member. Panel holding device. A fixing portion for fixing the holding member to another member is provided on an axis parallel to a panel surface of the holding member through a substantially center of the reflection type liquid crystal display panel. Item 7. A device for holding a reflective liquid crystal display panel according to any one of Items 1 to 6. The holding device according to claim 1, the reflective liquid crystal display panel held by the holding device, an optical path of light incident on the reflective liquid crystal display panel, and the reflective liquid crystal display panel. An optical unit using a reflective liquid crystal display panel, comprising: an optical system for forming an optical path of reflected light. 8. The holding device according to claim 1, the reflection type liquid crystal display panel held by the holding device, a projection optical system for projecting light to a projection surface, and the reflection of light from a light source. And a light guiding optical system for guiding the light reflected by the reflective liquid crystal display panel to the projection optical system. A projection type image display device comprising the optical unit according to claim 8 or the projection type display optical system according to claim 9.

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