JP2007212717A - Electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electronic equipment having high color reproducibility and long lifetime. <P>SOLUTION: The electronic equipment is a liquid crystal projector 11, having a plurality of liquid crystal light valves 12R, 13G, 14B modulating a plurality of kinds of color light having different wavelength bands, respectively according to image information to form an optical image, wherein each liquid crystal light valve has a liquid crystal layer, comprising a liquid crystal material which shows inclined vertical alignment, when no voltage is applied. The liquid crystal material of each liquid crystal light valve has a refractive index anisotropy Δn, which is smaller the shorter the wavelength of the color light is that is to be modulated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic device, and more particularly to an electronic device including a plurality of light modulation units that modulate colored light having different wavelength ranges.

  As an electronic device that displays an image, there is a projection display device that modulates light source light with, for example, a light modulation device using a liquid crystal panel into image light, and projects the image light on an image display unit such as a screen. . In general, as a projection display device capable of color display, each light source light having different wavelengths of R (red) color light, G (green) color light, and B (blue) color light is divided into three different liquid crystal panels. A so-called three-plate projection type color display device that performs color display by combining after modulation is known.

  In addition, a tilted vertical alignment type liquid crystal panel (liquid crystal display device) that controls liquid crystal having negative dielectric anisotropy so as to be aligned vertically when no voltage is applied is known. The tilted vertical alignment type liquid crystal panel controls the transmittance of light incident on the liquid crystal layer by utilizing the difference in refractive index between the major axis and the minor axis of the liquid crystal molecules. It has the property that the transmittance changes depending on the above.

For this reason, when an inclined vertical alignment type liquid crystal panel is used as a light modulation device for each color light of RGB in a three-plate projection type color display device, the applied voltage-transmittance characteristics of each liquid crystal panel are different, and color reproducibility Becomes lower. As a method of canceling the wavelength dependence of the applied voltage-transmittance characteristics of such a tilted vertical alignment type liquid crystal panel, the voltage level of the liquid crystal driving signal for driving each of the liquid crystal panels for each color light of RGB is set. Japanese Laid-Open Patent Publication No. 11-223808 discloses a liquid crystal display device that relaxes the wavelength dependence of applied voltage-transmittance characteristics of a liquid crystal panel for each color light of RGB by controlling in a driver processing circuit.
JP-A-11-223808

  However, as disclosed in Japanese Patent Application Laid-Open No. 11-223808, when the wavelength dependency of the applied voltage-transmittance characteristics of a tilted vertical alignment type liquid crystal panel is controlled by a circuit that drives the liquid crystal panel, The output from the circuit must be adjusted after grasping the wavelength dependency of the applied voltage-transmittance characteristics of the panel, and the adjustment work is complicated and requires time.

  In addition, when a three-plate projection type color display device is used for a long time (thousands to tens of thousands of hours), a liquid crystal panel that transmits B (blue) light is replaced with other R (red) light and G (green). ) The transmittance drops in a short time compared to a liquid crystal panel that transmits colored light. This is because the liquid crystal that transmits the B color light first deteriorates because the wavelength of the B color light is shorter than that of the other R and G color lights and has a higher energy. For this reason, there is a problem that the color reproducibility of the display of the projection type color display device is lowered, and further, the life of the projection type color display device is shortened.

  The present invention has been made in view of the above problems, and an object thereof is to provide an electronic device having high color reproducibility and a long lifetime.

  An electronic apparatus according to the present invention is an electronic apparatus including a plurality of light modulation units that form optical images by modulating a plurality of types of color light having different wavelength bands according to image information, respectively. The light modulation means includes a liquid crystal layer made of a liquid crystal material that has a negative dielectric anisotropy between a pair of substrates facing each other and that is inclined and vertically aligned with respect to at least one of the substrate surfaces when no voltage is applied. The liquid crystal material of the plurality of light modulation means has a smaller refractive index anisotropy as the wavelength of the color light to be modulated becomes shorter.

  According to such a configuration of the present invention, the refractive index anisotropy Δn of the liquid crystal light valve, which is a light modulation means for modulating light having higher energy, can be reduced, and light having high energy is modulated. The life of the liquid crystal light valve can be extended. In addition, by adjusting the value of refractive index anisotropy Δn, the wavelength dependency of the applied voltage-transmittance characteristics of the liquid crystal light valve is eliminated, so that electronic devices with high color reproducibility and long life are provided. can do.

  In the invention, it is preferable that the plurality of types of color light are red (R) color light, green (G) color light, and blue (B) color light, and the light modulation unit that modulates each of the three types of color light. The liquid crystal material has a refractive index anisotropy of ΔnR of the liquid crystal material of the light modulation unit that modulates the red (R) color light, and a refractive index of the liquid crystal material of the light modulation unit that modulates the green (G) color light. When the anisotropy is ΔnG and the refractive index anisotropy of the liquid crystal material of the light modulating means for modulating the blue (B) light is ΔnB, it is preferable that the relationship of ΔnR ≧ ΔnG> ΔnB is satisfied.

  According to such a configuration, the configuration other than the liquid crystal material of the liquid crystal light valve can be made the same and can be easily realized.

  Further, according to the present invention, the plurality of types of color light are red (R) color light, green (G) color light, and blue (B) color light, and the light modulation unit that modulates each of the three types of color light includes: The light modulation means for modulating the green (G) color light with the refractive index anisotropy of the liquid crystal material of the light modulation means for modulating the red (R) light as ΔnR and the thickness of the liquid crystal layer as dR. The refractive index anisotropy of the liquid crystal material is ΔnG, the thickness of the liquid crystal layer is dG, and the refractive index anisotropy of the liquid crystal material of the light modulation means for modulating the blue (B) light is ΔnB, When the thickness of the liquid crystal layer is dB, it is preferable that ΔnR ≧ ΔnG> ΔnB and dR ≦ dG <dB are satisfied.

  According to such a configuration, by increasing the thickness of the liquid crystal layer of the liquid crystal light valve that is a light modulation means for modulating light having higher energy, the liquid crystal light valve that modulates blue light is changed over time. Deterioration can be further suppressed.

  Moreover, it is preferable that the said electronic device is a projection type color display apparatus.

  According to such a configuration, it is possible to provide a projection type color display device that suppresses the collapse of color balance caused by deterioration due to secular change.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5.

  The overall configuration, particularly the optical configuration, of the liquid crystal projector 11 as an example of a projection type color display device, which is an electronic apparatus of the present embodiment, will be described. FIG. 1 is an explanatory diagram showing a schematic configuration of an optical system of the liquid crystal projector 11.

  The liquid crystal projector 11 of the present embodiment includes transmissive liquid crystal light valves 12R, 13G, and 14B, which are light modulation means, for each color light having different wavelength bands of R (red), G (green), and B (blue). 3 is a three-plate projection type color display device. The liquid crystal projector 11 projects and displays an image on the projection surface 60a of the screen 60 as display means. In the following, an observer (not shown) observes an image projected on the projection surface 60a from the same direction as the liquid crystal projector 11 with respect to the projection surface 60a.

  In the casing 11a of the liquid crystal projector 11, a projection optical system 40, an illumination optical system 20, and a color separation / synthesis optical system 30 are disposed.

  The illumination optical system 20 includes a light source 15, two fly eye lenses 16 and 17, and a polarization conversion device 18. The light source 15 includes a lamp 20a such as a high-pressure mercury lamp or a metal halide lamp, and a reflector 20b that reflects light L from the lamp 20a (hereinafter referred to as “light source light L”). Further, in order to make the illuminance distribution of the light source light L uniform in the liquid crystal light valves 12R, 13G, and 14B that are illuminated areas, two fly-eye lenses 16 and 17 are provided. Each fly-eye lens 16 and 17 is comprised by the some lens arrange | positioned two-dimensionally, respectively. In this way, the liquid crystal light valves 12R, 13G, and 14B are illuminated with uniform light intensity by the fly-eye lenses 16 and 17 with the light source light L. The polarization converter 18 is a polarization beam splitter array (not shown) provided on the fly-eye lens 17 side (hereinafter referred to as a PBS array) and 1 (not shown) for converting the polarization direction of polarized light reflected by the PBS array. / 2 wavelength plate, and the polarization direction of the light is aligned in one direction without impairing the light intensity of the light source light L.

  The color separation / combination optical system 30 includes two dichroic mirrors 21, 22, three reflection mirrors 23, 24, 25, three relay lenses 26, 27, 28, and three liquid crystal light valves 12R, 13G, 14B. And a cross dichroic prism 29.

  The dichroic mirrors 21 and 22 are formed, for example, by laminating a dielectric multilayer film having a predetermined wavelength selectivity on a glass substrate. The dichroic mirror 21 transmits the red light LR of the light source light L and reflects the green light LG and the blue light LB. The dichroic mirror 22 reflects the green light LG among the green light LG and the blue light LB reflected by the dichroic mirror 21 and transmits the blue light LB.

  As a result, in the color separation / synthesis optical system 30, the red light LR out of the light source light L incident from the illumination optical system 20 passes through the dichroic mirror 21, and then is reflected by the reflection mirror 23 to be a liquid crystal light for red light. The light enters the valve 12R. After the green light LG is reflected by the dichroic mirror 21, it is reflected by the dichroic mirror 22 and enters the liquid crystal light valve 12R for green light. The blue light LB is reflected by the dichroic mirror 21, then passes through the dichroic mirror 22, passes through a relay system including three relay lenses 26 to 28 and two reflection mirrors 24 and 25, and is a liquid crystal light valve for blue light. 14B.

  In the present embodiment, the liquid crystal light valves 12R to 14B as the light modulators are each configured as an active matrix transmissive liquid crystal light valve, and are driven by a drive circuit based on an image signal. Yes. The liquid crystal light valves 12R, 13G, and 14B display images corresponding to the respective colors. As a result, the red light LR, the green light LG, and the blue light LB that pass through the liquid crystal light valves 12R, 13G, and 14B, respectively, are modulated.

  The cross dichroic prism 29 has a structure in which a right angle prism is bonded, and a dielectric multilayer film that reflects the red light LR and transmits the green light LG is formed on one of the two mirror surfaces orthogonal to the cross shape. On the other side, dielectric multilayer films that reflect the blue light LB and transmit the green light LG are formed. Then, the three color lights of the red light LR, the green light LG, and the blue light LB are combined by the cross dichroic prism 29 to form light IL representing a color image. In the liquid crystal projector 11 of the present embodiment, the light IL is emitted from the cross dichroic prism 29 of the color separation / synthesis optical system 30 toward the projection optical system 40.

The projection optical system 40 includes a projection lens 42 that is a projection unit including an optical lens. The light IL representing the color image formed by the color separation / synthesis optical system 30 is enlarged and projected onto the projection surface 60 a of the screen 60 via the projection lens 42.

  Hereinafter, the configuration of the liquid crystal light valves 12R, 13G, and 14B, which are the liquid crystal device of the present embodiment, will be described below. FIG. 2 is a schematic cross-sectional view schematically showing a main part of the liquid crystal device in a state where no voltage is applied.

In the liquid crystal device 100, a liquid crystal layer 103 is sandwiched between a TFT (Thin Film Transistor) array substrate 101 and a pair of transparent substrates such as glass or quartz of a counter substrate 102.
On the liquid crystal layer 103 side of the TFT array substrate 101, a pixel electrode 104 which is a transparent conductive layer made of ITO (Indium Tin Oxide) or the like is formed. Further, a vertical alignment film 105 is provided on the pixel electrode 104. The vertical alignment film 105 is made of an organic material such as polyimide or an inorganic material made of silicon oxide, titanium oxide, or the like.

  On the other hand, the counter substrate 102 is disposed in parallel to the TFT array substrate 101 at a predetermined interval via a spacer and a seal material (not shown). A counter electrode 106 which is a transparent conductive layer made of ITO is formed on the counter substrate 102 on the liquid crystal layer 103 side, and a vertical alignment film 107 is further provided thereon.

  Further, polarizing plates 108 and 109 are disposed on the opposite sides of the TFT array substrate 101 and the counter substrate 102 from the liquid crystal layer 103, respectively. The arrangement of the polarizing plates 108 and 109 is a crossed Nicol arrangement.

  The liquid crystal layer 103 is injected and sealed in a region between the TFT array substrate 101 and the counter substrate 102 and surrounded by a sealing material (not shown). At this time, the thickness of the liquid crystal layer (hereinafter referred to as cell gap) is d [nm]. Liquid crystal molecules 103a, which are liquid crystal materials used for the liquid crystal layer 103, have negative dielectric anisotropy (Δε <0). Here, the dielectric anisotropy Δε is the dielectric constant (ε‖) in the molecular axis (major axis) direction of the liquid crystal molecule 103a and the dielectric constant (ε⊥) in the direction perpendicular to the molecular axis (short axis). The difference (Δε = (ε‖) − (ε⊥)) is expressed. The liquid crystal molecules 103a have a predetermined refractive index anisotropy Δn. The refractive index anisotropy Δn is a difference between the refractive index (n‖) in the molecular axis (major axis) direction of the liquid crystal molecule 103a and the refractive index (n⊥) in the direction perpendicular to the molecular axis (short axis) (Δn = (N‖)-(n⊥)).

  As shown in FIG. 2, in a state where no voltage is applied between the pixel electrode 104 and the counter electrode 106 (voltage non-application state), the liquid crystal of the liquid crystal layer 103 is controlled by the regulating force of the vertical alignment films 105 and 107. The molecules 103 a are aligned with an inclination substantially such that the major axis direction of the liquid crystal molecules 103 a is aligned with the normal direction of the TFT array substrate 101 and the counter substrate 102. In the liquid crystal molecule 103a, the major axis of the liquid crystal molecule 103a is set to a predetermined pretilt angle θp (for example, 1 to 10) with respect to the normal line of the surface of the TFT array substrate 101 and the counter substrate 102 as a substrate surface when no voltage is applied (Tilt degree) and tilt. In the present embodiment, as shown in FIG. 2, the liquid crystal molecules are aligned so that the major axis direction of the liquid crystal molecules is aligned with the normal direction of the surfaces (substrate surfaces) of a pair of opposing substrates, as shown in FIG. This form is called tilted vertical alignment (generally also called vertical alignment).

  Since the liquid crystal used for the liquid crystal layer 103 has negative dielectric anisotropy, the major axis direction of the liquid crystal molecules 103a of the liquid crystal layer 103 depends on the potential difference between the pixel electrode 104 and the counter electrode 106. The TFT array substrate 101 and the counter substrate 102 are tilted so as to be substantially parallel to the surfaces.

  The liquid crystal device 100 of the present embodiment having the above-described configuration transmits light incident on the liquid crystal layer 103 using a difference in refractive index between the major axis direction and the minor axis direction of the liquid crystal molecules 103a, that is, a birefringence phenomenon. It is what controls the rate.

  When no voltage is applied to the liquid crystal layer 103, the linearly polarized light that has entered the liquid crystal layer 103 through one of the polarizing plates 108 and 109 having orthogonal polarization directions is subjected to birefringence by the liquid crystal layer 103. In other words, the light is not emitted from the other polarizing plate. On the other hand, when a voltage is applied to the liquid crystal layer 103, the linearly polarized light that has entered the liquid crystal layer 103 through one of the polarizing plates 108 and 109 having polarization directions orthogonal to each other is inclined by the tilt angle of the liquid crystal layer 103. It becomes elliptically polarized light or circularly polarized light by birefringence according to the above, and is emitted from the other polarizing plate.

  As described above, the liquid crystal device 100 according to the present embodiment controls the voltage applied to the liquid crystal layer 103 for each of a plurality of pixels, thereby changing the transmittance of each pixel and modulating the light transmitted through the liquid crystal device 100. Is done. The transmittance of the liquid crystal device 100 is determined by the birefringence amount of the liquid crystal layer 103, which is determined by the retardation value Δn · d, which is the product of the refractive index anisotropy Δn and the cell gap d.

  The liquid crystal light valves 12R, 13G, and 14B included in the liquid crystal projector 11 of the present embodiment have the same configuration as the liquid crystal device 100 described above, but the value of the refractive index anisotropy Δn of the liquid crystal layer is respectively Different. Details of the configuration of the liquid crystal light valves 12R, 13G, and 14B will be described below.

  First, the liquid crystal light valves 12R, 13G, and 14B have a common cell gap d, pretilt angle θp, and dielectric anisotropy Δε, respectively, and these values are d = 3000 [nm] and θp = 85 [°. ], [Delta] [epsilon] =-5.0.

  Each of the liquid crystal layers of the liquid crystal light valves 12R, 13G, and 14B has a different refractive index anisotropy Δnx (hereinafter, x is assigned one of R, G, and B, and each of red, green, and blue colors) It represents a liquid crystal light valve for light).

  The liquid crystal layer of the liquid crystal light valve 12R for red light is ΔnR = 0.17, the liquid crystal layer of the liquid crystal light valve 13G for green light is ΔnG = 0.15, and the liquid crystal light valve 14B for blue light In the liquid crystal layer, ΔnB = 0.10.

  That is, each liquid crystal layer of the liquid crystal light valves 12R, 13G, and 14B of the present embodiment is made of a liquid crystal material having a smaller refractive index anisotropy Δn as the wavelength of the color light to be modulated is shorter. It is a well-known technique that the value of the refractive index anisotropy Δn of the liquid crystal material can be varied by adjusting the components of the liquid crystal material as in the present embodiment. A liquid crystal material having Δn can be purchased from a liquid crystal material manufacturer.

  The refractive index anisotropy Δn of the liquid crystal material of each of the liquid crystal layers of the liquid crystal light valves 12R, 13G, and 14B of the present embodiment is the voltage applied to the liquid crystal layer and the incident light of each wavelength as described below. The relationship (applied voltage-transmittance characteristic) with the transmittance of the pixel with respect to is determined to be close to all three.

  Regarding the liquid crystal light valves 12R, 13G and 14B configured as described above, the relationship between the voltage applied to the liquid crystal layer and the transmittance of the pixel with respect to incident light of each wavelength (applied voltage-transmittance characteristics) is shown in FIG. Shown as a graph. In FIG. 3, the horizontal axis represents the applied voltage [V], and the vertical axis represents the pixel transmittance [%]. In FIG. 3, the applied voltage-transmittance characteristics of the liquid crystal light valve 12R for red light, the liquid crystal light valve 13G for green light, and the liquid crystal light valve 13G for green light are shown by curves TR, TG, and TB. Show.

  As shown in FIG. 3, the applied voltage-transmittance characteristic curves TR and TG of the liquid crystal light valves 12R and 13G are substantially the same in the entire region. In addition, the applied voltage-transmittance characteristic curve TB of the liquid crystal light valve 14B substantially matches the other curves TR and TG from 0 [V] to the applied voltage VP at which the maximum transmittance TP is obtained. When the voltage is VP or higher, the transmittance tends to be lower than those of the other curves TR and TG.

  Here, as a comparative example, FIG. 4 shows the applied voltage-transmittance with respect to incident light of each wavelength when the refractive index anisotropy Δn of the liquid crystal layers of the liquid crystal light valves 12R, 13G, and 14B is all the same Δnc. The characteristics are shown as a graph in FIG. At this time, the characteristic values of the liquid crystal light valves are d = 3000 [nm], θp = 85 [°], Δε = −5.0, and Δnc = 0.15. In other words, FIG. 4 shows the applied voltage-transmittance characteristics for each wavelength when the same liquid crystal light valve is used for all color lights in different wavelength bands of red, green, and blue as in the prior art. It is a thing. In FIG. 4, the applied voltage-transmittance characteristics of red, green, and blue light are indicated by curves TR1, TG1, and TB1, respectively.

  As shown in FIG. 4, in the comparative example, the rise of the transmittance with respect to the applied voltage of the curve TR1 for red light is the slowest, and the rise of the curve TB1 for blue light is the steepest. For this reason, the applied voltages for obtaining the respective maximum transmittances of the red, green, and blue color lights are greatly different, and are about 2.4 [V] for blue light, whereas for red light, 5 [V] or more.

  As described above, the liquid crystal projector 11 including the liquid crystal light valves 12R, 13G, and 14B according to the present embodiment has the applied voltage-transmittance characteristics from the voltage non-applied state to the applied voltage VP that provides the maximum transmittance TP. Can be substantially matched. That is, the wavelength dependence of the applied voltage-transmittance characteristics of the liquid crystal light valves 12R, 13G, and 14B is eliminated. For this reason, according to the present embodiment, it is necessary to individually use a circuit having an output characteristic that matches the applied voltage-transmittance characteristic for each liquid crystal light valve that modulates colored light having different wavelength bands as in the prior art. There is no. In addition, according to the present embodiment, the applied voltage-transmittance characteristics of the liquid crystal light valves are almost the same, so that the adjustment operation of the output of the circuit that drives the liquid crystal light valves becomes easy or unnecessary. For this reason, according to this embodiment, there is an effect that the configuration of the circuit that drives each liquid crystal light valve of the liquid crystal projector 11 is simplified and the adjustment is facilitated.

  Conventionally, liquid crystal projectors using liquid crystal light valves using the same configuration and the same liquid crystal material for R (red) light, G (green) light, and B (blue) light have been used for a long time. In this case, there is a problem that the liquid crystal material of the liquid crystal light valve that transmits B (blue) light having a shorter wavelength and higher energy deteriorates faster than others.

  Here, FIG. 5 schematically shows changes in the usage time of the liquid crystal projector and the transmittance of each liquid crystal light valve. In FIG. 5, the vertical axis represents the maximum transmittance TP of the liquid crystal light valve for each color light, and the horizontal axis represents the usage time of the liquid crystal projector. In FIG. 5, TPR represents a change in maximum transmittance of red light, TPG represents green light, and TPB represents blue light. As shown in FIG. 5, in a conventional liquid crystal projector using all the same liquid crystal light valves, the liquid crystal material of the liquid crystal light valve for B (blue) color light deteriorates faster than the others, resulting in longer usage time. The B (blue) light transmittance TPB is significantly lowered as compared with the others, and the color balance is distorted.

  However, each of the liquid crystal layers of the liquid crystal light valves 12R, 13G, and 14B of the present embodiment is made of a liquid crystal material having a smaller refractive index anisotropy Δn as the wavelength of the color light to be modulated is shorter. In general, the smaller the value of the refractive index anisotropy Δn, the smaller the amount of light absorbed by the liquid crystal material, and thus the liquid crystal material is less likely to be deteriorated by light. For this reason, the liquid crystal light valve 14B of the present embodiment has a liquid crystal material that is hardly deteriorated, and can have a longer life than the conventional one. Therefore, according to the present embodiment, it is possible to realize a liquid crystal projector that is an electronic device in which color reproducibility does not deteriorate without losing color balance over a long period of use.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a graph showing applied voltage-transmittance characteristics of each liquid crystal light valve of the second embodiment. The liquid crystal projector of the second embodiment differs from the liquid crystal projector 11 of the first embodiment only in the configuration of each liquid crystal light valve. Therefore, only this difference will be described below, and the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

  The liquid crystal light valves for RGB color lights provided in the liquid crystal projector of this embodiment have different values of the cell gap d and refractive index anisotropy Δn of the liquid crystal layer. Details of the configuration of the liquid crystal light valve will be described below.

  First, the liquid crystal light valves for RGB color lights each have a common pretilt angle θp and dielectric anisotropy Δε, and their values are θp = 85 [°] and Δε = −5.0.

  Each liquid crystal layer of the liquid crystal light valve for each RGB color light has a different refractive index anisotropy Δnx (hereinafter, x is assigned one of R, G, and B, and each of red, green, and blue colors) It represents a liquid crystal light valve for light).

  The liquid crystal layer of the liquid crystal light valve for red light is ΔnR = 0.17, the liquid crystal layer of the liquid crystal light valve for green light is ΔnG = 0.15, and the liquid crystal layer of the liquid crystal light valve for blue light is ΔnB = 0.086.

  The cell gaps of the liquid crystal light valves for red light and green light are both dR = 3000 [nm], and the cell gap of the liquid crystal light valve for blue light is dB = 3500 [nm].

  That is, in this embodiment, each liquid crystal layer of the liquid crystal light valve for each color light of RGB is composed of a liquid crystal material having a smaller refractive index anisotropy Δn as the wavelength of the color light to be modulated is shorter, and further, for blue light. The cell gap dB of the liquid crystal light valve is set larger than the others.

  As shown in FIG. 6, according to the liquid crystal light valve for each color light of RGB configured as described above, each applied voltage-transmittance characteristic curve TR2, TG2, and TB2 is changed from 0 [V] to the maximum transmittance. It is possible to substantially match up to the applied voltage VP at which TP is obtained.

  Further, according to the present embodiment, the refractive index anisotropy Δn of the liquid crystal light valve for blue light is further smaller than that of the first embodiment, and the cell gap which is the thickness of the liquid crystal layer is large. As the cell gap is larger, the progress of deterioration of the liquid crystal material due to light becomes slower. Therefore, the liquid crystal light valve for blue light according to the present embodiment has higher durability against light than the first embodiment. Therefore, according to the present embodiment, it is possible to realize a liquid crystal projector in which the color balance does not go wrong over a longer period of use and the color reproducibility does not deteriorate.

  In the above-described embodiment, the liquid crystal light valve for each color light of RGB uses a liquid crystal material having a smaller refractive index anisotropy as the wavelength of the color light to be modulated is shorter. For example, for red and green light The liquid crystal light valve having the same structure may be used, and a liquid crystal material having a small refractive index anisotropy Δn may be used only for a liquid crystal light valve for blue light that is particularly easily deteriorated.

  In addition, the liquid crystal projector that is the electronic apparatus of the present embodiment is a so-called front-type projection display device that projects and displays an image on the screen from the observer side. A so-called rear projection display device that projects and displays an image on a screen from the side opposite to the observer may be used.

  The present invention is not limited to the above-described embodiments, and various modifications can be made as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification, and electronic devices accompanying such changes can also be used. It is included in the technical scope of the present invention.

It is explanatory drawing which shows schematic structure of the optical system of a liquid crystal projector. It is a cross-sectional schematic diagram which shows schematically the principal part in the voltage non-application state of a liquid crystal device. It is a graph which shows the relationship between the voltage applied to a liquid crystal layer, and the transmittance | permeability of the pixel with respect to the incident light of each wavelength. It is a graph which shows the applied voltage-transmittance characteristic of the conventional liquid crystal light valve. It is explanatory drawing which shows typically the use time of a liquid-crystal projector, and the change of the transmittance | permeability of each liquid-crystal light valve. It is a graph which shows the applied voltage-transmittance characteristic of the liquid crystal light valve of 2nd Embodiment.

Explanation of symbols

  11 liquid crystal projector, 11a housing, 12R liquid crystal light valve for red light, 13G liquid crystal light valve for green light, 14B liquid crystal light valve for blue light, 20 illumination optical system, 30 color separation / combination optical system, 40 projection optical system, 60 screen

Claims (4)

An electronic apparatus comprising a plurality of light modulation means for modulating an optical image by modulating a plurality of types of colored light having different wavelength bands according to image information,
The plurality of light modulators are made of a liquid crystal material that has a negative dielectric anisotropy between a pair of substrates facing each other and that is inclined and vertically aligned with respect to at least one of the substrate surfaces when no voltage is applied. A liquid crystal layer is sandwiched, and the liquid crystal material of the plurality of light modulation means has a smaller refractive index anisotropy as the wavelength of the color light to be modulated becomes shorter. The plurality of types of color light are red (R) color light, green (G) color light, and blue (B) color light,
The liquid crystal material of the light modulation unit that modulates the three kinds of color lights has a refractive index anisotropy of ΔnR and the green (G) of the liquid crystal material of the light modulation unit that modulates the red (R) color light. When the refractive index anisotropy of the liquid crystal material of the light modulation means for modulating color light is ΔnG, and the refractive index anisotropy of the liquid crystal material of the light modulation means for modulating blue (B) color light is ΔnB. In addition,
ΔnR ≧ ΔnG> ΔnB
The electronic device according to claim 1, wherein the relationship is satisfied. The plurality of types of color light are red (R) color light, green (G) color light, and blue (B) color light,
The light modulating means for modulating the three kinds of color light respectively has a refractive index anisotropy ΔnR of the liquid crystal material of the light modulating means for modulating the red (R) light and a thickness of the liquid crystal layer dR. The light that modulates the blue (B) light, where ΔnG is the refractive index anisotropy of the liquid crystal material of the light modulation means that modulates the green (G) light, and dG is the thickness of the liquid crystal layer. When the refractive index anisotropy of the liquid crystal material of the modulation means is ΔnB, and the thickness of the liquid crystal layer is dB,
ΔnR ≧ ΔnG> ΔnB and dR ≦ dG <dB
The electronic device according to claim 1, wherein the relationship is satisfied. The electronic device according to any one of claims 1 to 3, wherein the electronic device is a projection type color display device.

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