JPH06265842A - Projection type liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve the contrast ratio of an image reproduced on a screen and to obtain an image of high picture quality by the projection type liquid crystal display device, which projects an image of a reflection type light scatter mode liquid crystal panel on the screen by using a reflection type optical system, by preventing reflected light, generated on the border surface of optical components when lamp light passes through the optical system, from being projected on the screen. CONSTITUTION:A piano-convex lens which has only a convex surface on the side of a projection lens 12 is used as a 2nd condenser lens 7; and the condenser lens and a color separating and composing element, and the color separating and composing element and the reflection type light scatter mode liquid crystal panel are coupled across transparent optical media. Therefore, unnecessary reflected light generated on the incidence surface of the 2nd condenser lens 7 is scattered over a wide range, so the majority of the unnecessary reflected light is converged and cut off by a lens barrel, a light shield plate, etc., not to reach the screen, thereby providing the projection type display device which can reproduces an image of high picture quality with an improved contrast ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal display device for projecting an image displayed on a reflection type light scattering mode liquid crystal panel onto a screen by using a projection lens, and more particularly to a reflected light generated inside an optical system. The present invention relates to a projection-type liquid crystal display device that improves the image quality and reproduces a high-quality image with a good contrast ratio.

[0002]

2. Description of the Related Art Conventionally, as a large screen image display device, a projection type display device using a cathode ray tube has been generally used. However, because of the problem that the device is large and heavy,
Development of a lightweight display device has been desired, and a downsized projection type liquid crystal display device has been put into practical use by using a small, lightweight and thin liquid crystal panel. Most of projection type liquid crystal display devices use three transmissive TN (Twisted Nematic) liquid crystal panels or one transmissive TN liquid crystal panel to reproduce a color image on a screen. On the other hand, instead of the TN liquid crystal panel, for example, nematic liquid crystal is dispersed in a transparent polymer material, and the state of light transmitted through the liquid crystal panel is scattered or non-scattered depending on the magnitude of the voltage applied from the outside. A projection type liquid crystal display device using a transmission type light scattering mode liquid crystal panel is disclosed in Japanese Patent Laid-Open No. 4-113344.

A projection type liquid crystal display device using a reflection type light scattering mode liquid crystal panel is disclosed in Japanese Patent Laid-Open No. 19492/1992.
No. 1 publication is disclosed. This known example uses a projection optical system in which the central axis of lamp light for illuminating a reflection type light scattering mode liquid crystal panel is different from the central axis of light reflected from the liquid crystal panel.

[0004]

However, the projection type liquid crystal display device using the transmissive TN liquid crystal panel among the above-mentioned prior art uses two polarizing plates for the TN liquid crystal panel, and therefore about 60% of the incident light is absorbed. It will be absorbed by the polarizing plate. In addition, since the wiring electrodes and the active element portion necessary for driving the pixel must be made of an opaque material, the aperture ratio of the pixel portion (the ratio of the portion of the pixel portion through which the lamp light can pass) is small. Therefore, the light transmittance of the liquid crystal panel becomes about 10%. Therefore, about 90% of the lamp light is lost, and the reproduced image on the screen is dark, and the lamp must be used in a dark room. Further, when a high-power lamp is used to improve the screen brightness, there are problems that the power consumption increases, the temperature rise of the liquid crystal panel increases, and the operation becomes unstable.

On the other hand, in order to improve the light utilization rate of the liquid crystal panel, a light scattering mode liquid crystal panel which does not require a polarizing plate has been developed. Further, in order to solve the problem that the aperture ratio of the transmissive liquid crystal panel is small, a reflective scattering mode liquid crystal panel is formed in which a reflective electrode is formed on the wiring electrode and the active element part to improve the lamp light utilization rate. It has been proposed to improve the brightness of a reproduced image projected on a screen by using a reflective optical system. However, in the conventional reflection type projection optical system as shown in FIG. 10, the reflected light 18 is likely to be generated at the interface between the condenser lens 7 and the color separation / synthesis element 9, and the contrast ratio of the screen reproduced image is lowered. There was a problem. In particular, the surface from which the lamp light exits the condenser lens 7 of the biconvex lens is a concave surface, and therefore the reflected light 18 generated on the surface is converged and directed toward the screen 16 as if reflected by a concave mirror, It passes through the diaphragm 13 and is projected on the screen 16. When the unnecessary reflected light generated inside the optical system is projected on the screen in this way, the unnecessary reflected light is superimposed on the black portion of the reproduced image, and the brightness of the black portion of the reproduced image increases. As a result, the contrast ratio defined by the ratio of the brightness of the bright part and the brightness of the black part of the image reproduced on the screen is lowered, which causes a problem that a high-quality image cannot be reproduced.

An object of the present invention is to improve unnecessary reflected light generated inside an optical system in a projection type liquid crystal display device using a reflection type light scattering mode liquid crystal panel capable of displaying a bright reproduced image on a screen. It is an object of the present invention to provide a projection type liquid crystal reproducing device for reproducing a high quality image having a good contrast ratio.

[0007]

The above-mentioned object is to converge the light flux emitted from the lamp onto the mirror by the first condensing optical system, and to change the traveling direction of the lamp light by the mirror.
A second condenser lens, which is a plano-convex lens having a convex surface on the projection lens side, is arranged between the projection lens and the color separation / combination element at an interval of the focal length of the condenser lens from the mirror,
A substantially parallel lamp light is incident on a color separation / combination element coupled through the second condenser lens and an optical medium, and the lamp light is decomposed into light having different spectral components, and the color separation / combination element and the optical element are combined. At least two coupled through a medium
Illuminate more than one reflective light scattering mode liquid crystal panel, modulated according to the video signal content supplied to the scattering mode liquid crystal panel, the light reflected from the plurality of reflective light scattering mode liquid crystal panels, This is achieved by synthesizing by the color separation / synthesis element and projecting on the screen through the second condensing lens and the projection lens.

Further, in the case of a projection type liquid crystal display device using a single reflection type light scattering mode liquid crystal panel, the luminous flux emitted from the lamp is converged on the mirror by the first condensing optical system. Then, change the traveling direction of the lamp light by the mirror,
A second condenser lens composed of a plano-convex lens having a convex surface on the projection lens side is arranged between the projection lens and the reflection type light scattering mode liquid crystal panel at an interval of the focal length of the condenser lens from the mirror, Video signal contents supplied to the light-scattering mode liquid crystal panel by injecting substantially parallel lamp light into the reflection-type light-scattering mode liquid crystal panel coupled to the second condenser lens via an optical medium. It is achieved by projecting the light modulated and reflected in accordance with the above, onto the screen through the second condenser lens and the projection lens.

[0009]

By providing a second condenser lens having a convex surface on the side of the projection lens between the projection lens and the reflection type light scattering mode liquid crystal panel, it is possible to prevent the lamp light from entering the second condenser lens. The unnecessary reflected light generated on the convex surface of the lens is determined by the incident angle of the lamp light and the normal direction of the lens surface at the incident point. The unnecessary reflected light generated on the surface of the second condenser lens is as if reflected by the convex mirror.
The light is divergent while spreading over a wide range from the convex surface side of the second condenser lens. Therefore, most unnecessary reflected light can be blocked by the lens barrel of the projection lens, the diaphragm arranged between the projection lens and the second condenser lens, the light blocking plate, etc., and the unnecessary reflected light reaching the screen can be significantly reduced. . As a result, it is possible to reduce unnecessary light that has been superimposed on the black portion of the image reproduced on the screen, and it is possible to reproduce a high-quality image with a good contrast ratio.

Further, between the second condenser lens material and the color separation / synthesis element material, between the color separation / synthesis element material and the glass material of the reflection type light scattering mode liquid crystal panel, or the second condenser lens material. By coupling with the glass material of the reflective light scattering mode liquid crystal panel via an optical medium whose refractive index is substantially the same as that of the optical component material, unnecessary reflected light generated at the interface of the optical component is reduced, and a reproduced image is obtained. It is possible to prevent an increase in the brightness of the black portion of the image and reproduce a high-quality image with a good contrast ratio.

[0011]

EXAMPLES Examples of the projection type liquid crystal display device of the present invention will be described in detail below, but the present invention is not limited to the examples.

(Embodiment 1) FIG. 1 is a schematic configuration diagram showing a first embodiment. The main components of the projection type liquid crystal display device of the present embodiment are a lamp 1, a parabolic reflector 2, a light source section including a first condenser lens 5, a second condenser lens 7 including one plano-convex lens, A projection lens unit including a projection lens 12, a mirror 6, a light shielding plate 14, and a projection lens barrel 15, a color separation / synthesis element 9 for separating red, green, and blue light from white lamp light, and three primary color lights independently. The three reflection type light scattering mode liquid crystal panels 11R, 11G and 11B and the screen 16 which are modulated.

White light emitted from a lamp 1 such as a metal halide lamp, a xenon lamp or a halogen lamp is converted into a substantially parallel luminous flux by a lamp reflector 2 having a paraboloid of revolution. Infrared light of the lamp light is transmitted by the cold mirror 3 and visible light is reflected. Further, the cold filter 4 reflects infrared light and ultraviolet light from the lamp light to obtain light in the visible range. The first condensing lens (focal length f1) 5 and the mirror 6 in the lens barrel 15 of the projection lens are arranged so that the distance between them is substantially equal to the focal length f1 of the first condensing lens 5, and substantially parallel lamp light is emitted. It is converged on the mirror 6 by the first condenser lens 5. The traveling direction of the lamp light is changed by about 90 degrees by the mirror 6, and the projection lens 1
One second condenser lens having a convex surface on the second side (focal length f
2) The lamp light 157 is incident on 7. The second condenser lens 7 is a plano-convex lens having one convex surface, and the mirror 6
And the distance between the second condensing lens 7 and the focal length f2 of the lens.
The lamp light converged on the mirror 6 is converted into substantially parallel light by the second condenser lens 7 and is made incident on the color separation / combination element 9.

As the color separation / synthesis element 9, for example, a dichroic prism in which four triangular prisms are adhered and two kinds of dichroic films 9R and 9B are formed on the two diagonal surfaces thereof are used. The dichroic film 9R reflects the red light component from the white lamp light and transmits the blue and green light, and the dichroic film 9B reflects the blue light component from the lamp light and transmits the green and red light. Is transmitted through the dichroic films 9R and 9B and passes through the dichroic prism 9
Go straight on and exit. Therefore, the dichroic prism 9 splits the incident white lamp light into three primary color lights of red, green, and blue and emits the lights to different side surfaces, and a reflection type that displays images based on the red, green, and blue drive signals, respectively. The light scattering mode liquid crystal panels 11R, 11G, and 11B are illuminated.

The light-scattering mode liquid crystal panel used in this embodiment is, for example, a polymer dispersion type liquid crystal (Polymer Disp.
rsedLiquid Crystal hereinafter referred to as PDLC) is used. In addition to PDLC, polymer network liquid crystal (Polymer Network Liquid C
rystal), a liquid crystal material of smectic A phase, or the like can be used.

The sectional structure of the reflection type PDLC panel is, for example, one in which the PDLC is sandwiched between two substrates 10 and 150 as shown in FIG. One substrate 150 is a silicon single crystal or polycrystalline wafer, and the active element 15 such as a transistor or a diode is formed on the wafer.
1 is formed in large numbers, and a metal electrode 152 having a high reflectance such as aluminum which functions as a light reflection electrode is connected to the active element. The other substrate 10 is a transparent front plate substrate, and a transparent electrode 156 is provided on glass (or a plastic film). This is a structure in which a large number of nematic liquid crystals 154 microcapsulated in a substantially spherical shape are dispersed in a transparent resin material (polymer material) 153 provided between the substrates 150 and 10. The PDLC controls the light incident on the liquid crystal panel in a scattered or non-scattered state by utilizing the matching between the refractive index of the nematic liquid crystal and the refractive index of the polymer material forming the capsule.

When an electric field is not applied to the liquid crystal layer and the liquid crystal layer is OFF, the rod-shaped molecules of the liquid crystal are oriented along the capsule interface, and the liquid crystal molecules are oriented in various directions. Therefore, there is a difference in refractive index between the liquid crystal and the capsule (polymer material), and the incident light 157 is reflected by the reflective electrode 152 and then refracted in various directions at the capsule interface. The refracted light is further refracted in various directions in a chain in other surrounding capsules, and becomes scattered reflected light 158 that spreads in a wide range.
Since the light is emitted from the DLC panel, the pixel becomes cloudy and opaque.

On the other hand, when the liquid crystal layer is turned on by applying an electric field, the rod-shaped molecules of the liquid crystal are oriented in the direction of the electric field. At this time,
If a material is selected such that the difference in refractive index between the nematic liquid crystal and the capsule is small, refraction of light does not occur between the liquid crystal and the capsule. Therefore, the PDLC of the pixel becomes transparent, the incident light 157 is reflected by the reflective electrode 152, and the non-scattered light 159 is emitted from the PDLC panel. When the PDLC is turned on, the transmittance reaches nearly 85%, the light utilization efficiency can be more than doubled as compared with the TN liquid crystal using a polarizing plate, and a bright image can be reproduced on the screen.

The reflection type PDLC panel 11R, depending on the contents of the red, green and blue driving signals supplied to the PDLC panel,
The lamp lights of the three primary colors modulated by 11G and 11B are incident on the dichroic prism 9 again in a scattered or non-scattered state. The red light modulated by the PDLC panel 11R is the dichroic film 9R, the PDLC panel 11
The blue light modulated by B is reflected to the second condenser lens 7 side by the dichroic film 9B, and the PDLC panel 11
The green light modulated by G has two dichroic films 9R,
After passing through 9B, it is combined into a white light beam and emitted from the dichroic prism 9. When the PDLC panel of each color is ON, the non-scattered lamp light 159 exits the dichroic prism 9 as substantially parallel light, and enters the second condenser lens 7. The non-scattered light 159 is converged by the second condenser lens 7 in the vicinity of the opening of the diaphragm 13 arranged in the vicinity of the mirror 6, and then projected onto the screen 16 by the projection lens 12. Since the mirror 6 is arranged so as to be displaced from the central axis of the second condenser lens 7, the reflective PDLC panel 11 is provided.
Non-scattered lamp light 1 reflected from R, 11G, 11B
The second condenser lens 7 converges the light beam 59 at a position different from that of the mirror 6, passes through the aperture of the diaphragm 13, is projected by the projection lens 12, and reproduces a bright color image on the screen 16.

On the other hand, reflective PDLC panels 11R, 11
When G and 11B are OFF, scattered light 158 that spreads in various directions is reflected from the PDLC panel, but most of it is reflected by the portion other than the aperture of the diaphragm 13 and the projection lens barrel 1.
5, the light is blocked by the light shielding plate 14 or the like, or is reflected by the mirror 6 toward the first condenser lens 5 side, and the screen 1
The screen 16 is dark because it cannot reach 6. In this way, the diaphragm 13 and the second condensing lens 7 etc. make it possible to use the reflection type P
The so-called Schlieren optical system, which selects scattered light 158 and non-scattered light 159 modulated by the DLC panels 11R, 11G, and 11B, improves the contrast ratio of the image projected on the screen.

By the way, when the lamp light 157 enters the second condenser lens 7 from the air, the reflected light 18 shown by the dotted line is generated at the interface due to the difference in refractive index between the air and the lens material. I will end up. From air (refractive index na ≈ 1) to glass (eg crown glass, refractive index ng ≈
It is known that about 4.3% of the reflected light is generated at the interface when light is incident on 1.52). In order to reduce the reflected light generated at the interface between the air and the glass, magnesium fluoride or the like is vapor-deposited to form an antireflection film on the surface of the glass. About 4% of the reflected light is generated from about 1% to 0. Two
It is often done to improve the percentage.

However, in the reflection type optical system as in this embodiment, when the lamp light passes through the optical parts such as the lens, the reflection light generated on the surface thereof (hereinafter, in order to reproduce an image on the screen, Most of the unnecessary light is called unnecessary reflection light) and is directed to the screen 16 side, which causes a reduction in the contrast ratio of the image projected on the screen. Therefore, prevent unnecessary reflection light from reaching the screen surface. There is a need to. Especially in the optical system of the present embodiment, the unnecessary reflected light 18 generated by the lamp light 157 incident on the second condenser lens 7 is a main cause of lowering the contrast ratio. By the way, the unnecessary reflected light generated by the lamp light at the interface of the second condenser lens 7 generates unnecessary reflected light 18 in the direction according to Snell's law at the incident point. Second condenser lens 7
The relationship between the incident surface shape and the intensity of the unwanted reflected light projected on the screen was measured, and it was found that the intensity of the unwanted reflected light reaching the screen in the order of the concave surface, the plane, and the convex surface can be reduced. did. For example, unnecessary reflected light generated on a concave surface such as the exit surface of a biconvex lens or an incident surface of a concave lens becomes light that converges toward the screen direction as if reflected by a concave mirror, and most of the unnecessary reflected light is The screen 16 passes through the opening of the diaphragm 13.
Since the intensity of unnecessary reflected light projected on the screen is high, the contrast ratio is significantly reduced.
Further, when the incident surface such as the color separation / combination element 9 is a flat surface, the unnecessary reflected light is in a substantially parallel state, so that the unnecessary reflected light easily passes through the opening of the diaphragm 13 and reaches the screen 16. The contrast ratio decreases. On the other hand, when the incident surface is a convex surface, the unnecessary reflected light becomes light that diverges in a wide range as if it was reflected by the convex mirror, and most of the unnecessary reflected light is blocked by the diaphragm 13, the lens barrel 15, etc. It is possible to reduce the amount of light which reaches the screen 16 through the opening of the. Therefore, in order to improve the contrast ratio of the image reproduced on the screen, it is necessary to configure the second condenser lens 7 with a lens having a convex surface on the projection lens 12 side.

Therefore, in this embodiment, the second condenser lens 7 is a plano-convex lens (n having a convex surface on the projection lens 12 side).
g≈1.517, f2 = 123.0 mm, R2 = 63.
5 mm, R2 / D = 0.93). The antireflection film (not shown) is formed on the convex surface side of the second condenser lens 7 to reduce unnecessary reflected light generated at the interface between the air and the convex surface, and the lamp light 157 is secondly condensed. The light is made incident from the convex surface side of the lens 7 so that unnecessary reflected light generated on the incident surface is spread over a wide range so as not to proceed in the screen direction. That is, since the incident surface of the lamp light is a convex surface, the normal line direction of the convex surface at the incident point differs depending on the incident point, and the unnecessary reflected light 18 generated according to Snell's law at each incident point spreads in various directions. Most of the unnecessary reflected light 18 is blocked by the diaphragm 13, the light shielding plate 14, the lens barrel 15 and the like, and the unnecessary reflected light that reaches the screen 16 through the aperture of the diaphragm 13 is a second condenser lens including a concave surface. It was reduced to about 1/5 as compared with the case of. The direction (spreading degree) of the unnecessary reflected light 18 has a radius of curvature R2 of the convex surface.
And the angle of incidence of the lamp light. The radius of curvature R2 of the convex surface of the second condenser lens 7 is determined from (Equation 1) according to the refractive index ng of the lens material and the focal length f2 of the lens.

R2≈f2 (ng-1) (Equation 1) The relationship between the intensity of the unnecessary reflected light reaching the screen and the radius of curvature R2 of the convex surface of the second condenser lens was measured. Value R2 / normalized by lens aperture D
D is between 0.5 and 1.5, preferably 0.5 <R2 /
Within the range of D <1, the brightness due to the unnecessary reflected light can be reduced to a level at which there is no practical problem, and a reproduced image with a high contrast ratio can be obtained.

On the other hand, since the entrance surface and the exit surface of the dichroic prism 9 and the glass substrate 10 of the reflection type PDLC panel are flat surfaces, the unnecessary reflected light generated as described above becomes substantially parallel light and the aperture of the aperture 13 is opened. It easily passes through and is projected on the screen, which causes a reduction in the contrast ratio of the reproduced image on the screen. Therefore, the second condenser lens 7
In order to suppress unnecessary reflected light at the interfaces between the dichroic prism 9 and the dichroic prism 9 and the reflection type PDLC panels 11R, 11G, and 11B, it is transparent between the plane portion of the second condenser lens 7 and the incident surface of the dichroic prism 9. Optical medium 8 and dichroic prism 9
A transparent optical medium 8 is provided between the reflective PDLC panel 11R, the glass substrate 10 of the PDLC panel 11G, and the glass substrate 10 of the reflective PDLC panel 11B. The unnecessary reflected light generated at the interface between the optical component and the optical medium can be reduced by making the refractive index ratio between the optical component and the optical medium close to 1, and the refractive index of the optical medium is nm and the refractive index of the optical component material is ng. Assuming that the ratio of the two refractive indexes is p = nm / ng, the reflectance R of the unnecessary light generated at the interface between the optical component and the optical medium is expressed by Equation 2.

R = (1−p) · (1−p) / {(1 + p) · (1 + p)} (Equation 2) For example, crown glass (refractive index ng
.Apprxeq.1.517), a silicon oil having a refractive index substantially equal to the above-mentioned refractive index, for example, Immersion Oil A (MAX20234, nm.apprxeq.1.51) manufactured by Nikon
5) Alternatively, the reflectance R of the unnecessary reflected light can be reduced from about 0.00004% to 0.0005% by using an optical adhesive or an Artel adhesive Optocrail UT-20H (nm≈1.51). . By the experiment using the optical medium, the unnecessary reflected light generated at the interface of the optical component can be significantly reduced as compared with the above antireflection film, and a good result is obtained.

The optical medium is not limited to silicon oil or an optical adhesive, and it is preferable that the refractive index ratio p is approximately 1 in accordance with the refractive index of the optical component material, for example, silicon gel (nm≈). 1.42, Dow Corning Sylpot 368,184 or Shin-Etsu Chemical KE1
051, KE105, etc.), an ultraviolet curable resin (nm≈1.
47), an aqueous solution in which glycerin and ethylene glycol were mixed (nm≈1.42) and an ethylene glycol aqueous solution with a weight of 50% or more (nm≈1.45) also gave good experimental results.

Further, in this embodiment, after the optical components are brought into close contact with each other via the optical medium 8, the periphery thereof is sealed with a sealing material (for example,
Dow Corning 784 ELECTRICAL S
Although it is surrounded by EALANT), it goes without saying that the thickness of the optical medium layer can be set arbitrarily by providing a seal structure that prevents the optical medium from leaking.

(Embodiment 2) FIG. 3 is a schematic configuration diagram showing a second embodiment of the projection type liquid crystal display device of the present invention. The same parts as those in the first embodiment (FIG. 1) are designated by the same reference numerals. Attached. The projection type liquid crystal display device of this embodiment has one reflection color P
The difference from the first embodiment is that the DLC panel 11C is used and the dichroic prism 9 in the first embodiment is omitted. Since the reflection type PDLC panel 11C having a built-in color filter can reproduce a color image with only one liquid crystal panel, the projection type liquid crystal display device can be made compact and inexpensive.
The operations of the second condensing lens 7 made of a plano-convex lens and the optical medium 8 are the same as those in the first embodiment, and thus the description thereof is omitted.

(Embodiment 3) FIG. 4 is a schematic structural view showing a third embodiment of the projection type liquid crystal display device of the present invention. The same parts as those in the first embodiment (FIG. 1) are designated by the same reference numerals. Attached. The projection type liquid crystal display device of this embodiment is the same as that of the second embodiment shown in FIG.
In contrast to the first embodiment, a glass block 19 having the same shape and the same glass material as the dichroic prism is used instead of the dichroic prism 9 which is the color separation / synthesis element in the first embodiment. . The reflection type PDLC panel 11C with a built-in color filter is 1
A color image can be reproduced only with a single liquid crystal panel, so that the projection type liquid crystal display device can be made compact and inexpensive as in the second embodiment. By providing the glass block 20, the projection type liquid crystal display device can be used in the first embodiment. The same back focus as the projection lens 12 (from the projection lens 12 to the PDLC panel 1
Since the optical distance can be set to 1C), the projection lens 12 can be shared with the first embodiment using three PDLC panels, and the cost of the optical system can be reduced. The operations of the second condensing lens 7 made of a plano-convex lens and the optical medium 8 are the same as those in the first embodiment, and thus the description thereof is omitted.

(Embodiment 4) FIG. 5 is a schematic constitutional view showing a fourth embodiment of the projection type liquid crystal display device of the present invention. The same components as those in the first embodiment (FIG. 1) are designated by the same reference numerals. Attached. The projection type liquid crystal display device of this embodiment is a red and blue two-color PDLC panel 11RB and a monochrome PDL for green.
By using the C panel 11G, instead of the dichroic films 9R and 9B for separating and combining the three primary colors in the first embodiment,
It is different from the first embodiment in that a dichroic prism 90 having a dichroic film 9RB that reflects red and blue lights and transmits green light is provided. The dichroic film 9RB formed on the dichroic prism 90 reflects red and blue light from white lamp light and transmits green light, so that the PDLC having red and blue color filters is used.
The panel 11RB is illuminated with red and blue light, and the monochrome PDLC panel 11G is illuminated with green light. When the PDLC panels 11G and 11RB having the same number of pixels are used, the number of pixels of the PDLC panel 11G for green can be doubled for red and blue. Therefore, since the number of green pixels that most contributes to the resolution can be increased, it is possible to reproduce a color image having a higher resolution than in the embodiments shown in FIGS. Therefore, using two reflective PDLC panels,
Although the resolution is slightly inferior to that of the first embodiment using a single PDLC panel, a projection type liquid crystal display device having good resolution can be realized at low cost. The operations of the second condensing lens 7 made of a plano-convex lens and the optical medium 8 are the same as those in the first embodiment, and thus the description thereof is omitted.

(Embodiment 5) FIG. 6 is a schematic constitutional view showing a fifth embodiment of the projection type liquid crystal display device of the present invention. The same components as those in the first embodiment (FIG. 1) are designated by the same reference numerals. Attached. The projection type liquid crystal display device of this embodiment is different from that of the first embodiment shown in FIG. 1 in that the second condenser lens has a plano-convex lens 70 having a convex surface facing the projection lens 12 and a convex surface facing the projection lens 12 side. The difference is that the convex meniscus lens 71 is provided. The second condenser lens 7 having a convex surface facing the projection lens 12 side
The operations of 0 and 71 and the optical medium 8 are the same as those in the first embodiment, and therefore their explanations are omitted. Further, the number of the second condensing lenses is not limited to two, and the point is that the second condensing lens may be configured by a lens having no concave surface on the projection lens 12 side.

(Embodiment 6) FIG. 7 is a schematic structural view showing a sixth embodiment of the projection type liquid crystal display device of the present invention. The same parts as those in the first embodiment (FIG. 1) are designated by the same reference numerals. Attached. The projection type liquid crystal display device of this embodiment is different from the first embodiment shown in FIG. 1 in that it has two types of dichroic mirrors 91R and 9R combined in an X shape instead of the dichroic prism 9.
It is different in that it is provided with 1B filled with an optical medium 8 such as silicon oil. The operation of these dichroic mirrors is similar to that of the dichroic prism 9, and the purpose is to reduce the manufacturing cost thereof as compared with the dichroic prism. The operations of the second condensing lens 7 made of a plano-convex lens and the optical medium 8 are the same as those in the first embodiment, and thus the description thereof is omitted.

(Embodiment 7) FIG. 8 is a schematic constitutional view showing a seventh embodiment of the projection type liquid crystal display device of the present invention. The same components as those in the first embodiment (FIG. 1) are designated by the same reference numerals. Attached. The projection type liquid crystal display device of this embodiment is different in the lamp reflector 20 from the first embodiment shown in FIG. The lamp reflector 20 is an ellipsoidal mirror, in which the lamp 1 is arranged at the first focal point position and the mirror 6 is arranged at the second focal point position so that the lamp light is almost in the second focal point position only by the ellipsoidal mirror. The first condensing lens, which was necessary for the first embodiment, was omitted by converging on. It should be noted that the second lens composed of a plano-convex lens
Since the operations of the condenser lens 7 and the optical medium 8 are the same as those in the first embodiment, the description thereof will be omitted.

The lamp reflector is not limited to a parabolic mirror or an ellipsoidal mirror, but may be a combination of a spherical mirror and a plurality of lenses, and a lamp reflector combining a plurality of surface shapes is used. Is also good.

(Embodiment 8) FIG. 9 is a schematic structural view showing an eighth embodiment of the projection type liquid crystal display device of the present invention. The same parts as those in the first embodiment (FIG. 1) are designated by the same reference numerals. Attached. The projection type liquid crystal display device of this embodiment is different from the first embodiment shown in FIG. 1 in that the arrangement of the projection lens 12, the lamp 1, the lamp reflector 2 and the first condenser lens 3 is exchanged.
With this configuration, the depth dimension of the optical system (the dimension between the tip of the projection lens 12 and the PDLC panel 11B) can be reduced. The operations of the second condensing lens 7 made of a plano-convex lens and the optical medium 8 are the same as those in the first embodiment, and thus the description thereof is omitted.

[0037]

According to the present invention, since a polarizing plate is not necessary, a light scattering mode liquid crystal panel having a small light loss is a reflection type liquid crystal panel, thereby increasing the light utilization rate and reproducing a bright image on a screen. In the display device, by spreading the unnecessary reflected light generated in the reflection type optical system over a wide range, most of the unnecessary reflected light is stopped, blocked by a lens barrel, a light shielding plate, etc. so as not to reach the screen, To realize a projection display device for reproducing a high-quality image having a good contrast ratio.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a projection type liquid crystal display device showing a first embodiment of the present invention.

FIG. 2 is a diagram illustrating the structure and operation of a reflective light scattering mode liquid crystal used in the projection type liquid crystal display device of the present invention.

FIG. 3 is a schematic configuration diagram showing a projection type liquid crystal display device showing a second embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing a projection type liquid crystal display device showing a third embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a projection type liquid crystal display device showing a fourth embodiment of the present invention.

FIG. 6 is a schematic configuration diagram showing a projection type liquid crystal display device showing a fifth embodiment of the present invention.

FIG. 7 is a schematic configuration diagram showing a projection type liquid crystal display device showing a sixth embodiment of the present invention.

FIG. 8 is a schematic configuration diagram showing a projection type liquid crystal display device showing a seventh embodiment of the present invention.

FIG. 9 is a schematic configuration diagram showing a projection type liquid crystal display device showing an eighth embodiment of the present invention.

FIG. 10 is a schematic configuration diagram showing a conventional projection type liquid crystal display device.

[Description of Reference Signs] 1 ... Lamp, 2, 20 ... Lamp reflector, 5 ... First condenser lens, 7, 70, 71 ... Second condenser lens, 8 ... Optical medium, 9, 90 ... Dichroic prism, 11R, 1
1G, 11B, 11C, 11RB ... Reflective light scattering mode liquid crystal panel, 12, 120 ... Projection lens, 13 ... Aperture, 14
... Shading plate, 15 ... Lens barrel, 16 ... Screen

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeru Mori 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa, Ltd. Inside Hitachi Media Media Research Laboratories

Claims (13)

[Claims] 1. A projection type liquid crystal display device comprising a lamp, a condensing optical system, a projection lens and a reflection type light scattering mode liquid crystal panel, wherein a projection lens is provided between the projection lens and the reflection type light scattering mode liquid crystal panel. A projection type liquid crystal display device comprising a lens having no concave surface on its side. 2. A projection type liquid crystal display device having a lamp, a condensing optical system, a projection lens, a color separation / combination element, and a plurality of reflective light scattering mode liquid crystal panels, wherein the projection lens and the color separation / combination element are combined. In the meantime, one plano-convex lens having a convex surface on the projection lens side is coupled via the color separation / synthesis element and an optical medium, and the color separation / synthesis element and a plurality of reflective light scattering mode liquid crystal panels are optically coupled. A projection type liquid crystal display device characterized by being coupled via a medium. 3. A projection type liquid crystal display device having a lamp, a condensing optical system, a projection lens, and one reflection type light scattering mode liquid crystal panel, wherein the projection lens and the reflection type light scattering mode liquid crystal panel are provided between the projection lens and the reflection type light scattering mode liquid crystal panel. A projection type liquid crystal display device characterized in that one plano-convex lens having a convex surface on the projection lens side is coupled to the reflection type light scattering mode liquid crystal panel via an optical medium. 4. A means for converging a light beam emitted from a lamp by a first condensing optical system and changing a traveling direction of the lamp light by a mirror arranged inside a lens barrel of the projection lens, and the projection lens. A second condenser lens composed of a plano-convex lens having a convex surface on the projection lens side is arranged between the color separation / synthesis element and the color-separation / synthesis element at an interval of a focal length of the second condenser lens from the mirror, thereby providing a second collection lens. Means for injecting substantially parallel lamp light to a color separation / combination element coupled through an optical lens and an optical medium; and light having different spectral components from the lamp light, and through the color separation / combination element and an optical medium. Means for illuminating at least two reflective light-scattering mode liquid crystal panels coupled to each other, and a plurality of the light-scattering mode liquid crystal panels modulated according to the contents of the video signal supplied to the liquid crystal panels. A projection type liquid crystal having means for synthesizing emitted light by the color separation / synthesis element, and means for reproducing an image by projecting on the screen through the second condenser lens and the projection lens. Display device. 5. The second condenser lens comprises a spherical lens or an aspherical lens having a convex surface on the projection lens side,
Ratio R2 / D of radius of curvature R2 of the convex surface and lens aperture D
Is between 0.5 and 1.5. 5. The projection type liquid crystal display device according to claim 1, wherein 6. The projection type liquid crystal display device according to claim 5, wherein the ratio R2 / D is between 0.5 and 1.0. 7. A refractive index ratio p (where p <1) between the optical medium and the second condensing lens material is 0.9 or more, and the optical medium and the color separation / synthesis element are combined. 6. The projection according to claim 2, wherein a refractive index ratio with a material and a refractive index ratio between the optical medium and the front transparent plate material of the reflection type light scattering mode liquid crystal panel are 0.9 or more. Liquid crystal display device. 8. The ratio p is 0.93 or more, and the refractive index ratio between the optical medium and the color separation / combination element material and the front transparency of the optical medium and the reflection type light scattering mode liquid crystal panel. 8. The projection type liquid crystal display device according to claim 7, wherein the refractive index ratio to the plate material is 0.93 or more. 9. The projection type liquid crystal display device according to claim 2, wherein the thickness of the optical medium is 10 mm or less. 10. The projection type liquid crystal according to claim 9, wherein the thickness of the optical medium is such that one optical component and the other optical component through the optical medium are substantially brought into close contact with each other. Display device. 11. The projection type liquid crystal display device according to claim 2, wherein the second condenser lens comprises one plano-convex lens and a plurality of convex meniscus lenses. 12. The projection lens, the second condenser lens,
12. The projection type liquid crystal display device according to claim 2, wherein the mirror, the diaphragm, and the light shielding plate are provided inside a lens barrel. 13. The reflective light scattering mode liquid crystal panel,
A nematic liquid crystal is dispersed and held in a smectic A-phase liquid crystal material or a polymer material, and a structure including capsular nematic liquid crystals independently dispersed in the polymer material or in the polymer material is provided. 13. The projection type liquid crystal display device according to claim 2, wherein the projection type liquid crystal display device has a structure in which a nematic liquid crystal that is continuous through a porous slit is included.