JPH085979A - Projection type display device having filter - Google Patents

Abstract

PURPOSE:To obtain a good color balance and projected images of a high contrast ratio. CONSTITUTION:This projection type display device is provided with a light source optical system, a first filter 1, a first diaphragm 17, a condenser lens 13, a liquid crystal display element 15, a second diaphragm 18, a second filter 2 and a projecting optical system so as to constitute a Schlieren optical system. The light passage characteristics of the first and second filters are so changed as to compensate the wavelength spectral characteristics of the scatterability of the liquid crystal display element 15. The transmission quantity or reflection quantity of the light source light is adjusted according to the spectra of RGB, by which the dependency of the scatterability of the liquid crystal display element 15 on wavelengths is compensated and the light source light having high directivity is obtd. The bright and easily visible projected image light is thus obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission / scattering type display device, and more particularly to a projection type display device using a liquid crystal display device and an illuminating device using the same.

[0002]

2. Description of the Related Art A display element is roughly classified into a light absorption type element and a light scattering type element according to its optical function. As an example of the former, a TN liquid crystal display element (TN-L) using a polarizing plate is used.
CD). As the latter, a dynamic scattering type liquid crystal display element (DS-LCD), a display element in which a minute dipole responsive to an electromagnetic field is sandwiched between electrodes, and the like are already known.

This light-scattering type display element obtains a display function by modulating light using scattering and non-scattering (transmission) of light in the functional layer. As this new light scattering type liquid crystal display element,
A liquid crystal display device including a liquid crystal solidified composite having various characteristics (liquid crystal solidified matrix composite, hereinafter referred to as LCSM) has been proposed (hereinafter, a liquid crystal display device including the liquid crystal solidified composite). Is referred to as LCSM-LCD).

The basic structure thereof is LCS in which a nematic liquid crystal having positive dielectric anisotropy is dispersed and held in a solidified matrix such as a resin in which a polymer is cured between substrates with electrodes.
The M layer is sandwiched. And the ordinary refractive index (n ₀ ) of the liquid crystal in which the refractive index (n _P ) of the solidified matrix is used,
It is matched with either the extraordinary light refractive index (n _e ) or the refractive index (n _x ) when the liquid crystal is randomly aligned. LCS is generated by turning on and off the applied voltage between both electrodes.
The liquid crystal molecules in the M layer are controlled by an electric field to obtain an optically transparent state (light transmission) and a light shielding state (light scattering).

Since the light control principle of this LCSM-LCD depends on the refractive index matching and the light scattering in the microstructure in the LCSM layer, the relation between the light scattering property and the wavelength is not always constant. In addition, when a transmission type scattering liquid crystal display element having the above wavelength characteristics is used in combination with a projection type display device among various modes for realizing a display function, the display characteristic has a wavelength (image display). The color tends to change depending on the color tone. For example, there is a tendency that the black portion becomes dark brown.

Usually, L having a transmission / scattering type operation mode
The scattering power of CSM-LCD depends on the wavelength, and the shorter the wavelength, the higher the scattering power. In addition, although it depends on the combination of the solidified material and the liquid crystal, the shorter the wavelength, the lower the transmittance in the transparent state.
FIG. 20 shows an example of the spectral transmittance characteristics of the LCSM-LCD in the scattering state, the transparent state and the intermediate state. This is because the divergence angle of the incident light on the LCSM-LCD and the converging angle of the light projected from the LCSM-LCD on the screen through the projection lens are 7 °.
Is measured as a spectral transmittance characteristic.

FIG. 21 shows the wavelength dependence characteristic of the contrast ratio represented by the transmittance ratio in the transparent state and the scattering state (related to the light-dark ratio on a certain projection screen). It is measured under the same conditions as in FIG. The contrast ratio is lower on the longer wavelength side.

Therefore, when the LCSM-LCD is used for a projection type display device, short wavelength light is short and long wavelength light is excessive in the modulated image light, so that the projected image having a lower color temperature than the light source color. Becomes Particularly, from a dark level of an image display to a halftone level, an excessive amount of projection light accompanied by a low scattering power of long wavelength light causes the color tone of a projection screen to become dark brown, resulting in deterioration of image quality.

In order to improve such problems, the following conventional examples are known. LC in Conventional Examples 1 to 4
The present invention relates to a liquid crystal display device having a light modulation function layer having almost the same function as SM.

Conventional example 1 is the invention disclosed in Japanese Patent Laid-Open No. 3-98022. In the projection type liquid crystal display device, white light emitted from a single light source system is color-divided into three colors of R, G, and B by a dichroic mirror and then made incident on three liquid crystal display elements respectively, and the emitted light is dichroic. After color combination with a mirror, a single projection lens is used to project on a screen. The feature of the prior art example 1 is that the balance of the projected image contrast ratio of each color can be controlled by configuring the liquid crystal display element provided for each color differently according to the color wavelength.

Specifically, the particle size of the liquid crystal particles in the resin used as the solidified substance is set to be different for each of R, G, and B so that the maximum scattering power can be obtained in each color wavelength range. Alternatively, by changing the thickness of the LCSM layer and increasing the thickness of the LCD (also referred to as an LC cell or panel) capable of supporting long wavelengths, the three LCDs have almost the same scattering ability. In the case of the conventional example 1, three Ls of RGB
It is necessary to make different specifications for each CD.

FIG. 22 is a schematic diagram showing an example of the system configuration of the projection type display device of the first conventional example. The color separation / combination optical system is referred to as "Proceeding of Japan Display", 1992, p. 113.
It is the same as that disclosed in Japan display '92 p113 ".

Next, as prior art 2, WO93 / 2378
The invention disclosed in No. 7 will be described. Its constitution is characterized by mixing a red-color absorbing dichroic dye in the liquid crystal, and there is almost no red absorption in the transparent state in which a voltage is applied, and the red transmittance is generated in the scattering state in which no voltage is applied. And to reduce the wavelength dependence of the contrast ratio.

In this case, a red dichroic dye is required. Further, when a projection light source with high illuminance is used, the temperature rise inside the LCD due to the absorption of red light cannot be ignored. In general, liquid crystals and dyes have problems in durability and property maintenance at high temperatures. Therefore, in a projection display device that requires the use of a light source for projection with high illuminance, a cooling means, for example, must be separately used in order to use a light absorber. May be required.

Conventional example 3 is the invention disclosed in Japanese Patent Laid-Open No. 5-158019. In this invention, RG is set for each pixel.
A projection type color display device is constructed by using a single LCD (single plate full color) having a B color filter.
The feature is that by changing the thickness of each of the R, G, and B color filters inside one LCD, the conventional example 1
Similarly, by providing different LCSM layers for each color, the projected image contrast ratio of each color can be made substantially the same. Therefore, it is necessary to adjust the thickness of the color filter or the film formed thereon for each RGB.

Generally, the cell gap between the glass substrates holding the LCSM layer has a diagonal size of 2 sizes (inch) or more.
In the case of CD, it is usually made uniform by scattering spacers. However, in this Conventional Example 3, since the unevenness is provided in the cell, it is very difficult to control the uniform cell gap in the plane of the LCD more than ever. Alternatively, it is necessary to achieve uniform cell gap without spacers. A new manufacturing technique is required to make the concavo-convex color filter of Conventional Example 3 effectively function.

Next, the conventional example 4 in which the light from the light source is divided into a plurality of light beams to obtain a good optical effect will be described. Japanese Patent Laid-Open No. 5-
It is the invention described in 210165. The feature is that the light source light is split into at least two light fluxes by the split aperture, then made incident on the LCD, and combined with the diaphragm which is another optical element to obtain a bright and high-contrast projection image. . In addition, the shape of the aperture of the aperture may be a non-circular rectangle or an ellipse (half circle + rectangle +
The semicircle), the ellipse, etc. are used to further effectively use the luminous flux. In the present invention, since the divided aperture can function as a new secondary light source, it is possible to improve the directivity of light.

Finally, a system configuration of a basic optical system in a projection type display device using a transmission / scattering type display element will be described. A Schlieren optical system is generally used to display a projected image with a high contrast ratio. The construction is, for example, by Dayway et al., Proceeding of SID Vol. 18/2 Vol. 1977 No. 13
Pp. 5-146 ("Proceedings of S.
I. D vol. 18/2, 1977 page 13
5 to 146 (A. G. Deway) ").

The basis of the Schlieren optical system is to form a conjugate image of a light emitting source in a light source optical system or a secondary radiation light source on the side of a projection optical system via a transmission / scattering type display element. This is to distinguish the component in which the azimuth of the emitted light has changed from the azimuth of the incident light and the component that does not change, and project one of them on a screen or the like.

In a transmission / scattering type display element that does not use the diffractive action of light, it is necessary to project a light component (for example, light that has passed through an LCD in a transparent state) whose azimuth of incident light does not change. It is preferable in terms of improving the light utilization efficiency as a whole and achieving a high contrast ratio.

Therefore, the light source in the light source optical system,
Alternatively, a diaphragm having an opening with the same shape as the conjugate image of the secondary radiation source is placed at the position where the conjugate image of the secondary radiation source is formed, and the transmission and scattering type display element blocks the light component whose incident light direction has changed. It is preferable to provide such a configuration on the projection optical system side.

[0022]

DISCLOSURE OF THE INVENTION The present invention provides a projection type display device using a transmission scattering type display element in which the scattering power changes depending on the wavelength, and by providing auxiliary optical means, the arrangement is simple. It is an object of the present invention to provide a high-performance projection display device and an application device using the same, by reducing the wavelength dependence of the contrast ratio of the projected image and the change of the color balance in the halftone even if there is any.

[0023]

In the present invention, a light source optical system, a transmission / scattering type liquid crystal display element, and a projection optical system are provided, and light source light emitted from the light source optical system passes through the liquid crystal display element. A projection type display device that is projected from a projection optical system, and is a liquid crystal at the position of a virtual light source between the light source optical system and the liquid crystal display element in the optical path from the light source optical system to the projection optical system. A filter for compensating the display characteristics of the display element is arranged. Then, it functions to adjust the contrast characteristic and the spectral characteristic of the projected image.

The configuration will be described more specifically. First,
A light source optical system including a light source, a transmission / scattering type liquid crystal display element, and a projection optical system are provided, and the light source optical system, the liquid crystal display element, and the projection optical system are arranged to form a Schlieren optical system, A projection type display device in which light emitted from a light source is passed through a liquid crystal display element and then projected from a projection optical system, wherein a virtual light source is set in an optical path from the light source to the liquid crystal display element, and the virtual light source The filter has a plurality of regions, and at least one region allows only a certain wavelength region of the light to pass therethrough, and further, there is an optical path from the virtual light source to the projection optical system. Thus, a first projection display device is provided in which a liquid crystal display element is arranged at a non-imaging position of a virtual light source.

Here, the light passing surface substantially refers to a functional surface that is provided on the light incident surface or the light emitting surface, the inside of the filter, or the like, and determines light transmission and light shielding. Each area has the same function as a so-called independent color correction filter.

Further, a light source optical system having a light source, a transmission / scattering type liquid crystal display element and a projection optical system are provided, and the light source optical system, the liquid crystal display element and the projection optical system constitute a Schlieren optical system. A projection type display device in which the light emitted from the light source is passed through the liquid crystal display element and then projected from the projection optical system, and a virtual light source is set in the optical path from the light source to the liquid crystal display element. The first filter (1) is arranged at the position of the virtual light source, and the light passing surface of the first filter (1) is provided with a plurality of regions, and at least one region is only a certain wavelength band of light. Further, the liquid crystal display element is disposed in the optical path from the virtual light source to the projection optical system in the non-imaging position of the virtual light source, and further in the optical path after the liquid crystal display element. At the image forming position of the filter (1) Providing a second projection type display apparatus characterized by a filter (2) is disposed.

Further, a light source optical system, a transmission / scattering type liquid crystal display element (15) and a projection optical system are provided, and light source light emitted from the light source optical system is passed through the liquid crystal display element (15). Then, the light is projected from the projection optical system, and the light source optical system includes a light source (11), an elliptical mirror (12), and a first diaphragm (1).
7) and a light source (11) near the position of the first focal point of the elliptical mirror (12) and a first diaphragm (17) near the position of the second focal point of the elliptic mirror (12). A first filter (1) is further arranged in the vicinity of the first diaphragm (17),
A plurality of regions s _X (X
= 1 to n, n ≧ 2), and at least one region allows only a certain wavelength region of light to pass therethrough, and the liquid crystal display device (1
The effective aperture area of the region of the first filter (1) corresponding to the wavelength region of low scattering power of 5) is smaller than the effective aperture area of the region of the first filter (1) corresponding to the wavelength region of high scattering power. Is provided so as to be relatively small, and a condenser lens (13, 13) is provided at a position before or after the liquid crystal display element (15) or both before and after the liquid crystal display element (15) in the optical path from the light source optical system to the projection optical system. 131, 132) are provided, and the diffused light that has passed through the first diaphragm (17) is collected by the condenser lens (13, 13).
1, 132), a conjugate image of the first diaphragm (17) is formed at substantially the pupil position of the projection optical system, and a second diaphragm (18) is provided near the image plane. , The aperture shape of the second diaphragm (18) is formed so as to substantially match the conjugate image of the first diaphragm (17), and the second filter (2) is provided in the vicinity of the second diaphragm (18). And a plurality of regions s _Y (Y = 1 to n, n ≧ 2) are provided on the light passage surface of the second filter (2) as in the first filter (1), and at least one region is provided. Provides a third projection type display device characterized by allowing only a certain wavelength range of light passing through the liquid crystal display element (15) and the second diaphragm (18) to pass therethrough.

In the above-mentioned second or third projection type display device, the first filter (1) or the second filter (2) may have a light-passing surface or the first filter (1).
When both the light-transmissive surface of the second filter (2), a region s _A to allowed to pass only the wavelength band A in the central wavelength lambda _A, area center wavelength allowed to pass through only the wavelength range B of lambda _B s _B And the areas occupied by the regions s _A and s _B on the light passage surface are K _A and K _B , respectively, the fourth projection is characterized by satisfying the relationship of Formula 1. Provide a type display device. Here, s _A and s _B mean any two areas of the plurality of areas.

[0029]

[Equation 1]

In the above second or third projection type display device, either the first filter (1) or the second filter (2), or the first filter (1) and the second filter (2). Both filters (2) of R (red), G
(Green) and B (blue) are provided with regions corresponding to three wavelength ranges,
A fifth projection display device is provided, in which the effective aperture areas K _R , K _G , and K _{B of} each region are changed according to the scattering power of the liquid crystal display element.

In the fifth projection type display device described above, R (red), G (green) and B of the second filter (2) are used.
The aperture shapes of the respective regions corresponding to the three wavelength regions of (blue) are the regions corresponding to the three wavelength regions of R (red), G (green) and B (blue) of the first filter (1). A sixth projection display device is provided so as to substantially match the conjugate image of the aperture shape.

Further, in the projection type display device according to any one of the second to fifth aspects, the first filter (1) and the second filter
Filter (2) is W (white), B (blue), BG (blue +
A seventh projection type display device is provided, wherein each region is divided and provided according to three wavelength regions of (green). Here, W (white) means that wavelengths in the entire visible range are transmitted.

Further, there is provided an eighth projection type display device characterized in that, in any one of the above first to seventh projection type display devices, a light transmission type filter is used.

Further, there is provided a ninth projection type display device characterized by using a light reflection type filter in any one of the above first to seventh projection type display devices.

Further, in any one of the above-mentioned first to ninth projection type display devices, each region divided according to the wavelength range of the light passing through the filter is fan-shaped and as a whole is substantially radial. A tenth projection-type display device is provided which is provided with arranged filters.

Further, in the projection display device according to any one of the first to ninth embodiments, a filter in which each region divided according to the wavelength range of light passing through the filter is provided in a stripe shape is used. An eleventh projection-type display device is provided.

Further, in the projection display device according to any one of the first to ninth embodiments, a filter is used in which the shape of the region divided according to the wavelength range of the light passing through the filter is substantially circular. A twelfth projection-type display device is provided.

In the projection display device according to any one of the first to twelfth aspects, the light source optical system has an elliptical mirror (1
2) and the light source is arranged in the vicinity of the first focal position, and the cone is arranged in the vicinity of the second focal position, and the cone is a light-transmitting cone-shaped prism. A convex cone-shaped prism having an apex angle α1 of 90 ° to 175 ° on the cone surface of
Alternatively, a thirteenth projection display device is provided which is a concave pyramidal prism having an apex angle β1 of 185 ° to 270 °.

In the projection display device according to any one of the first to twelfth aspects, the light source optical system includes an elliptic mirror (1
2) and the light source is arranged in the vicinity of the first focus position thereof, and the cone is arranged in the vicinity of the second focus position, and the cone is a light-reflecting cone-shaped reflector. The convex cone-shaped reflector having an apex angle α2 of the conical surface of the reflector of 150 ° to 177 ° or the concave cone-shaped reflector having an apex angle β2 of 183 ° to 210 °. The projection type display device is provided.

In the projection display device according to any one of the first to fourteenth aspects, the liquid crystal display element holds the nematic liquid crystal having positive dielectric anisotropy dispersed in the solidified matrix between the substrates with electrodes. A liquid crystal display device of the transmission and scattering type, which has a liquid crystal solidified substance composite material and in which the refractive index of the solidified substance matrix is matched with the ordinary light refractive index (n ₀ ) of the liquid crystal used. 15 projection-type display devices are provided.

In the projection display device according to any one of the first to fifteenth aspects, the liquid crystal display element has a reflection layer, and the incident light is reflected normally by the reflection layer and then emitted. A sixteenth projection type display device characterized in that projection is provided.

Further, there is provided an illuminating device characterized by using any one of the above-mentioned projection type display devices.

In the present invention, the wavelength range or spectrum means light having a continuous or discrete spectrum in a wavelength band of at least 100 nm or more.
In most cases, it shows light in the visible wavelength region spectrum.

[0044]

Unlike the so-called simple color correction filter, the filter of the present invention can adjust the contrast ratio of the projected image and the color balance. That is, the spectral light amount and the spectral luminous flux of the light passing through the filter are adjusted (shape and size), and white light source light that normally has the entire spectrum is adjusted according to the spectral transmission characteristics of the liquid crystal display element having wavelength dependence. By compensating, the directivity of light is adjusted for each spectrum to make the projected image bright and have a high contrast ratio.

In general, in a projection type display device using a transmission / scattering type display element, the light source optical system, the projection optical system and the transmission / scattering type display element are constituted so as to satisfy the positional relationship of the Schlieren optical system. It is possible to display the contrast (contrast) of the projected image. At this time, the brightness of the projected image depends on the directivity of light emitted from the light source optical system and incident on the display element, the scattering ability of the display element, and the numerical aperture (F number) that determines the converging angle of the projection optical system. It depends. This is significantly different from the case of a transmissive absorption type display element in which bright and dark (contrast) display is determined by the characteristics of the display element itself and has little dependence on the optical system.

In particular, in a scattering state (intermediate state) where a completely transparent state cannot be achieved, the proportion of scattered transmitted light that contributes to the projection light is determined by the light incident from the light source optical system in the Schlieren optical system to the transmissive scattering type display element. It changes depending on the directivity and the converging angle of the projection optical system. That is, when the scattering power of the transmission-scattering type display element is different depending on the wavelength, in the Schlieren optical system, the filter according to the present invention is changed by the above-mentioned configuration according to the wavelength so as to reduce the wavelength dependence. Just do it.

As shown in FIG. LCSM-LCD
In the scattering state (T _ON ) until reaching the transparent state (T _ON ).
_{In the OFF} ) and intermediate state (T _M ), the scattering power is usually lower in the longer wavelength region, and the conventional projection type display optical system tends to have a relatively high transmittance in the long wavelength region.

According to the configuration of the projection type display device of the present invention,
In the scattering state (T _OFF ) and the intermediate state (T _M ) up to the transparent state (T _ON ), the wavelength dependence of the transmittance is reduced, and the color balance from spectral dark to bright is achieved. Can be suppressed, and the on / off contrast ratio for each color can be made uniform.

Further, since the filter of the present invention is installed at a distance from the display element and the light transmitted through the filter becomes diffused light and enters the display element, the color distribution existing on the filter surface is reflected on the display element surface. Is hard to be reflected. In other words, the filter is arranged at the virtual image forming position of the light source, and the light amount and the luminous flux for each wavelength region (spectrum) are adjusted (actually, the diaphragm area).
In the Schlieren optical system described above, the light from the light source is dispersed in the optical path, and there is a position where the light is emitted almost uniformly (non-imaging positions of the light source and the virtual light source).

By disposing the display element at this position, a substantially uniform full-color display image can be obtained. Further, the conjugate image of this filter is formed by the condenser lens, and its position coincides with the pupil position of the projection lens, so that the illuminance distribution and the color distribution existing on the filter surface do not affect the projection image. The illumination method for such a display element is called a uniform illumination method (Keller illumination method).

Examples of system configurations in the present invention are shown in FIGS. 1 to 4 for each arrangement of condenser lenses. 1 to 3 show the case where the transmission / scattering type display element is used in a transmission type (through mode), and FIG. 4 shows a case where a reflection layer is provided inside or on the non-incident surface side of the transmission / scattering type display element. Is used in a reflection type (reflection mode) in which light is reciprocated through a light modulation functional layer (a layer that causes light scattering). Here, a lens is used as a light emitting source in a light source optical system or an optical element that forms a conjugate image of a secondary radiation light source, but instead, an imaging action such as an elliptical mirror or a spherical mirror may be used. .

Each component will be described with reference to FIGS. First filter 1, first diaphragm 17, first condenser lens 131 (used as a substantially collimating lens), liquid crystal display element 15, second condenser lens 132, second filter 2, Two diaphragms 18 are provided. The condensing lens is not a two-lens constitution, but the condensing lens 1 as shown in FIGS.
A single sheet like 3 may be used. The first filter and the second filter are arranged in the vicinity of the first diaphragm and the second diaphragm. Almost all can be configured. In addition,
Illustration of the color separation / combination optical system is omitted.

At this time, the size and shape of the first diaphragm that will form the light emission source or the secondary radiation light source (virtual light source) in the light source optical system, and the transmission / scattering type display element or the condenser lens. The directivity of the incident light to the transmission / scattering type display element is determined by the positional relationship of. Then, the transmission / scattering display is performed by the positional relationship between the second diaphragm having an opening having substantially the same shape as the conjugate image of the light emission source or the secondary radiation light source in the light source optical system and the transmission / scattering display element or the condenser lens. Of the transmitted light of the element, the directivity of the emitted light that passes through the projection optical system and is projected on the screen or the like is determined.

In the present invention, in the projection type display device using the transmission / scattering type display element in which the scattering characteristic has wavelength dependence, the direction of the incident light to the transmission / scattering type display element in the basic configuration of the Schlieren optical system described above is directed. And the directivity of outgoing light that is transmitted through the transmissive-scattering display element and projected onto a screen or the like is adjusted to be different depending on the wavelength, thereby compensating for the wavelength dependence of the scattering characteristics of the transmissive-scattering display element. , The wavelength dependence of the contrast ratio of the projected image and the change in the color balance in the halftone are reduced.

Specifically, first, the size of the first diaphragm serving as a light emitting source or a secondary radiation source in the light source optical system
The size and shape of the second diaphragm having the same shape as the conjugate image of the first diaphragm formed by the condenser lens are changed.

The present invention is generally applicable to an optical system using a transmission / scattering type display element, but is specifically directed to a general-purpose liquid crystal display element (LCD).

As the transmission / scattering type (light scattering type) LCD, several systems such as DS-LCD and liquid crystal phase change mode have been reported. Among them, the above-mentioned LCSM-LCD
Is particularly preferable because it can operate at a low voltage (≦ 10 V) and has a high scattering ability. Usually, the structure of an LCSM-LCD used for a projection type display device is such that a nematic liquid crystal having a positive dielectric anisotropy is high between a first substrate on which electrodes and driving elements are formed and a second substrate on which a counter electrode is formed. An LCSM layer composed of dispersed and held molecules in a solidified matrix such as a cured resin is sandwiched. Further, the refractive index of the solidified matrix is usually matched with the ordinary refractive index (n ₀ ) of the liquid crystal used.

The structure of the LCMS layer is such that liquid crystals are enclosed in liquid bubbles of a solidified matrix made of resin or the like,
A substantially single particle shape (spherical shape, spheroidal shape, etc.) is preferable from the optical effect, but individual liquid crystal capsules may not be completely independent but may be partly in communication. It suffices if it has a microstructure capable of substantially equivalently functioning as a single particle. Further, liquid bubbles of individual liquid crystals may be communicated with each other through a slit such as porous glass or porous resin.

The physical properties of the liquid crystal used are 0.20 ≦
The range of Δn ≦ 0.25 and 5 <Δε <13 is preferable because a low hysteresis characteristic in the VT curve and a contrast ratio during transmission and scattering (high transmittance and high scattering) can be obtained. In addition, when the refractive index (n _P ) of the resin or the like used as the solidified matrix and the ordinary refractive index (n _O ) of the liquid crystal substantially match each other, a transmissive state is established. For example, n _O −
It is preferably used so as to satisfy the relationship of 0.03 <n _P <n _O +0.05.

In the case of a projection type display device using an LCSM-LCD having such a transmission / scattering type operation mode, a projection image is obtained by using the optical system (projection type display device 100) of the entire system shown in FIG. Angle dependence (contrast ratio T _ON when the applied voltage is 7 V and the transmittance T _OFF when there is no applied voltage, T _ON / T _OFF ) of the contrast ratio (red contrast ratio C _R at wavelength 610 nm, wavelength Green contrast ratio C _G at 540 nm, blue contrast ratio C at wavelength 470 nm
_B ) is shown in FIG.

This projection type display device 100 is provided with an elliptical mirror 12, a light source 11 and a first diaphragm 17 in a light source optical system. The total reflection mirror M and the collimating lens 731 adjust the luminous flux of the light source light. Further, dichroic mirrors 141 and 142 and total reflection mirrors M2 and M3 set at an incident angle of 30 ° are provided. Further, liquid crystal optical elements 75R, 75G, and 75B are provided for each color light, and condenser lenses 732R, 732G, and 732B are provided after the respective optical paths. The second diaphragm 18 is arranged at a position in the optical path where a conjugate image of the first diaphragm 17 is formed. Further, a projection optical system including the projection lens 19 is arranged.

In FIG. 23, the converging angle indicates the directivity of projection light, which will be described later. As shown in this figure, the smaller the converging angle (which means closer to parallel light), the higher the contrast ratio, and the larger the converging angle, the lower the contrast ratio tends to be. .

Further, as can be seen from C _R , C _G , and C _B measured at the main wavelengths of each band of RGB, the light-convergence angle dependence of the contrast ratio changes according to the wavelength. Therefore, in general, when an LCSM-LCD is used, the longer the wavelength, the lower the contrast ratio, and the projected image does not become gray, especially at a dark level, but becomes brownish. Furthermore, FIG.
As shown in, even in the halftone region where the transparent state (T _ON ) is not reached, the transmittance (T _M ) becomes higher as the wavelength becomes longer, as in the scattering state (T _OFF ).

On the other hand, the contrast ratio is the incidence on the display element.
High directivity depends on the directivity of the light and the directivity of the projected light.
The higher the contrast ratio, the higher the value. In addition,
Even in the region, the transmittance of the scattering state (T_OFF ) As well as fingers
Light with a higher directivity has a transmittance (T _M ) Will be low. Accordingly
The longer the projected light in the wavelength range, the higher the directivity of the light.
By providing an optical system, the contrast ratio of the projected image
Balun in the halftone region and wavelength dependence in
It is possible to reduce the change in voltage.

1 to 4, the aperture diameter determined by the size and shape of the light emitting source or secondary radiation source in the light source optical system is D1, and the conjugate image of this light emitting source or secondary radiation source is Let D2 be the aperture diameter of the diaphragm arranged at the position where the conjugate image is formed and having the same shape as the conjugate image. Here, when it corresponds to the light emitting portion of the light emitting source, or when the light emitted from the light emitting source is condensed at a focal position by an elliptical mirror or the like, an aperture stop is arranged at the focal position, and the aperture is secondary. When used as a radiation source, D1 means its average diameter.

That is, this light emitting portion (first in FIGS.
S1 is the total area (corresponding to the aperture area of the diaphragm of).

[0067]

[Equation 2]

Here, there are a plurality of light emitting portions or a plurality of separated regions or openings s _X (X = 1 to n, n ≧
When the aperture stop is composed of 2), S1 is approximated by its total area Σs _X.

Similarly, regarding the second diaphragm provided at the position where the conjugate image of the light emitting portion is generated, if the total area of the openings of the second aperture diaphragm is S2, D2 is given by the following equation. To be done. Here, s _Y is defined similarly to s _X. S
2 = Σs _Y (Y = 1 to n, n ≧ 2).

[0070]

(Equation 3)

At this time, the dispersion angle φ (φ which represents the directivity of the light emitted from the light source optical system and incident on the transmission / scattering type display element.
_A , φ _B , φ _C ) can be approximated by the following equation, where L1 is the shorter one of the intervals between the light emitting section, the condenser lens, and the transmission / scattering type display element.

[0072]

[Equation 4]

Further, the converging angle δ (δ _A , δ _B , δ _C ) representing the directivity of the outgoing light which passes through the internal projection optical system of the transmitted light of the transmissive-scattering type display element and is projected onto the screen is , Of the distances between the second diaphragm, the condenser lens, and the transmission-scattering type display element, whichever is shorter, is approximated by the following equation.

[0074]

(Equation 5)

Therefore, in order to change the directivities φ and δ of the incident light and the projected light to the transmission / scattering type display element according to the wavelength, D1, L1, which are related by the equations 4 and 5,
Either D2 or L2 may be changed according to the wavelength. In the present invention, it means that among these, D1 and D2 are substantially adjusted for each spectrum to improve the directivity.

In order to maintain the brightness, that is, the projection efficiency without deteriorating the contrast ratio of the projected image, the dispersion angle φ
And condensing angle δ are approximately equal to D1, L1, D
It is preferable to set 2 and L2. In order to adjust L1 and L2, it is necessary to change the focal length of the optical lens, which complicates the configuration of the entire system. In particular, three types of optical lenses are required when configuring a color separation / combination optical system of RGB three colors. On the other hand, when D1 and D2 are adjusted, it is possible to achieve them with a single component even if the color separation / combination optical system is used.

Further, when the transmission power of the transmission scattering type display element used is low, when the first aperture stop and the second aperture stop are composed of a plurality of separated regions or apertures s _X and s _Y , or An aperture having a long outer peripheral length is preferable because it has a higher contrast ratio than a single circular aperture stop. Note that, here, the description will be made assuming that the diaphragm and the filter are substantially integrated.

As shown in FIGS. 20, 21, and 23, when an LCSM-LCD having a tendency of wavelength dependence or light collection angle dependence of transmittance and contrast ratio is used,
A plurality of regions having different transmission characteristics (transmission and cutoff) are provided on the light passage surfaces of the first filter (1) and the second filter (2).

For example, light is divided into three wavelength bands of BGR, two of which are wavelength bands A and B, and the central wavelengths of the respective wavelength bands are λ _A and λ _B. The first filter 1 and the second filter 2 may be configured so as to satisfy the relationship of the above-described Expression 1 when the areas occupied by the respective wavelength regions on the light passing surface of the filter are K _A and K _B. preferable. Furthermore, it is more preferable to satisfy the relationship of Expression 6.

[0080]

(Equation 6)

In the present invention, R indicating the wavelength range is about 590 to 670 nm, G is about 500 to 560 nm, and B is about 420 to 460 nm.
It refers to the wavelength band of 490 nm. The cutoff wavelength may be shifted and used depending on the relationship with other optical elements used. Further, although a gap is provided between the wavelength bands in order to improve color purity, the gap amount can be adjusted in relation to the entire system.

[0082]

【Example】

(Embodiment 1) FIG. 5 shows a projection type display device 10. In this embodiment, the light source 11 is a first ellipsoidal mirror 12 (spheroidal mirror).
The light emitted from the light source 11 is placed at the focal point and the elliptic mirror 1
The light is reflected by 2 and is incident from the plane side of the convex cone-shaped prism 3 provided substantially at the second focal position, and the light is refracted on the plane and propagates inside the prism, and further refracted on the cone surface to be convex. By exiting from the conical surface of the conical prism 3, the azimuth distribution of the light flux after exiting through refraction transmission changes. And
The light enters the first condensing lens 131, becomes substantially parallel light, and enters the transmission / scattering type liquid crystal display element 15.

The non-scattered light which is transmitted without being scattered by the functional layer of the liquid crystal display element 15 and has passed through the liquid crystal display element 15 is
The light collecting lens 132 collects the light substantially at the position of the projection lens 19 and projects it on a screen (not shown). However, the scattered light scattered by the liquid crystal display element 15 deviates from the regular optical path, for example, the second light. It is removed by the diaphragm 18 and is not projected on the screen.

The vicinity of the opening of the first diaphragm 17 and the second diaphragm 1
A first filter and a second filter are arranged near the opening of 8, respectively. The filter used in this embodiment is a filter formed so that each optical path area and the amount of passing light can be adjusted according to the wavelength range (spectrum) of passing light. In practice, it may be formed almost integrally with the first or second diaphragm.

The light source 11 used here is a discharge light emission type metal halide lamp, a xenon lamp, a filament light emission type halogen lamp or the like, and any of them is an electrode of the light source section, a tube glass, a heat insulating film, a filament or the like. Since the light shielding portion is present, the emitted light in the vicinity of the parallel azimuth angle with the optical axis emitted from the light source is small, and the reflected light from the elliptical mirror 12 has a small amount of the emitted light component in the vicinity of the parallel azimuth angle with the optical axis.

As a result, in the case of the conventional example shown in FIG. 22 in which the cone-shaped prism 3 is not used, there is a shortage of light whose angle with the optical axis at the second focal point of the elliptical mirror 12 is about 10 ° or less,
A shadow was formed near the center of the transmission / scattering type display element (75R, 75G, 75B), but when the conical prism 3 was used,
The refraction at the prism interface changes the azimuth angle of the light flux, compensating for the lack of light whose angle with the optical axis is less than about 10 °, and correcting the light intensity non-uniformity near the center of the transmission / scattering display element to make it uniform Was done.

The pyramidal prism can be used by arranging the flat surface on the exit surface side and the conical surface on the entrance surface side in addition to the illustrated arrangement. Further, in this case, since the filter of the present invention can be provided on the flat surface side, it is more preferable because a simpler integrated structure can be taken. This is advantageous when adjusting the aperture size using an iris diaphragm.

A spheroidal mirror is usually used as the condenser mirror of the light source optical system, but in principle, it should have a function of forming a point light source secondarily. For example, there is a combination of a parabolic mirror and a condenser lens although the directivity is lowered. Further, as the elliptic mirror, a smooth quadric surface is not used, but a multi-mirror elliptic mirror in which minute regions are combined intricately to form an elliptic mirror as a whole can be used. Further, an elliptical mirror in which two or more kinds of elliptical surfaces are combined can be used. Further, according to the shape of the diaphragm or the shape of the liquid crystal display element, it is possible to use a flat elliptical mirror body in which the cross section of the elliptical mirror shows a substantially ellipse in the plane whose normal is the optical axis.

Each part constituting this embodiment (FIG. 5) will be described. In this embodiment, a counter substrate having an ITO transparent electrode and an active matrix driving substrate having a TFT formed for each pixel ITO electrode are used, and a sealing material is applied to form a cell having a constant space gap. afterwards,
A liquid mixture of a liquid crystal and a polymer is injected into the cell, and the polymer is cured by irradiating it with ultraviolet rays to form a resin, forming an LCSM. In particular, what is formed by using a polymer is called a liquid crystal polymer composite (liquid crystal polymer composite: hereinafter referred to as LCPC).

Then, a transmission / scattering type liquid crystal display device was obtained.
Here, the LCPC layer provided in the liquid crystal display element has a form in which a nematic liquid crystal having positive dielectric anisotropy is dispersed and held in a resin. In this case, it is preferable that the so-called liquid crystal capsules are partially communicated with each other or have a form of substantially independent particles in order to obtain high scattering ability.

The display portion of the liquid crystal display element 15 has a diagonal size of 3, the pixel aperture ratio is 40%, and the maximum transmittance is 30.
%.

The light source optical system includes a light source 11 (metal halide lamp with a light emission arc length of 4 mm and 150 W), an elliptical mirror 12 (first focal length f1 = 22 mm, second focal length f).
2 = 105 mm, total depth H = 50 mm, convex cone-shaped prism 1 (vertical angle α1 = 114 °, bottom cross-sectional diameter 30 m)
m, height 12 mm, but the height of the inclined surface of the conical prism is 9.74 mm). First as a condenser lens
Condensing lens 131 (plano-convex lens with focal length 150 mm) and second condensing lens 132 (focal length 150 mm
Plano-convex lens).

A first diaphragm 17 using an iris diaphragm with a variable aperture diameter is provided between the conical prism 3 and the condenser lens 131 near the second focal position of the elliptical mirror 12.

Of the light that has passed through the liquid crystal display element 15, only the light that has passed through the second diaphragm 18 is the projection lens 1
An image is formed on the screen as a liquid crystal display image through 9.

At this time, an iris diaphragm with a variable aperture diameter is similarly used at the pupil position of the projection lens, which is the position where the conjugate image of the aperture diameter of the first diaphragm 17 is formed by the second condenser lens 132. The second diaphragm 18 that has been used is arranged.

Next, a structure for changing the directivity of light according to the wavelength in this embodiment will be described below.

In the vicinity of the opening of the first diaphragm 17 and in the vicinity of the opening of the second diaphragm 18, radial first and second filters 1 and 2 having an optical axis as a symmetrical axis as shown in FIG. 6 are respectively provided. Install it so that the longer the wavelength range, the smaller the area occupied by the aperture diameter. The spectral characteristics are shown in FIG.

Specifically, as shown in FIG. 6, R / G / B
A filter in which the optical path area is divided for each of the three color spectra of is used. In this filter, the aperture diameter is determined from the above-described equations 3 and 4 according to the occupied area S corresponding to the wavelength range of each color.
Further, the dispersion angle φ and the light collection angle δ are determined by the equations 4 and 5. Here, δ = φ, and the first condenser lens 131
Since the focal length of the second condenser lens 132 is 150 mm, L1 = L2 = 150 mm. Therefore, when δ = 6 ° with respect to R, the occupied area becomes K _R = 1.95 cm ² .

Here, the relationship with the characteristics of the liquid crystal display element will be described. When a transmissive-scattering liquid crystal display device including an LCPC layer having the wavelength dependence and the collection angle dependence of the contrast ratio shown in FIG. 23 is used, G and B have the same contrast ratio as R. For this purpose, the light collection angle δ may be set to 6.6 ° (G) and 7.4 ° (B).

Therefore, the first filter 1 and the second filter 1
In the filter 2 of No. ² , the respective occupied areas for the wavelength regions G and B are K _G = 2.36 cm ² and K _B = 2.98 cm ² . That is, the RGB occupation area ratio of the filter in FIG. 6 may be divided so as to satisfy K _R : K _G : K _B = 1: 1.21: 1.53. In the example of FIG. 6, R / G
・ B has two areas each and is divided into 6 areas in total.

An iris diaphragm is used as the first diaphragm 17 and the second diaphragm 18 in which the circumference of the opening is substantially maintained and the outer circumference is increased or decreased to change the opening area. With the iris diaphragm that determines the actual aperture diameter, the total aperture area is S = K _R + K _G + K _B = 7.29c
As will be m ^2, i.e., the opening diameter 30. 5 mm
And it is sufficient. In this case, the wavelength dependence of the projected image is reduced, and the contrast ratio of 1 over almost the entire visible light range.
00: 1 or more is obtained.

By making the color division of the first filter 1 and the second filter 2 into a shape as shown in FIG.
Even if 1 and D2 are changed by the iris diaphragm, the area ratio for each wavelength region does not change and remains substantially constant. Therefore, the opening diameter D1, depending on the brightness of the surroundings where the projected image is to be used,
By changing D2 with the iris diaphragm, the brightness and contrast ratio of the projected image can be adjusted at the same time. Under a certain brightness environment, even if both aperture stops are set so as to obtain an optimum contrast ratio, a display that is easy to see and a color balance is constant.

Generally, when a light source other than a point light source is used,
It is difficult to efficiently obtain highly directional light from the light source optical system, and the smaller the dispersion angle φ, the lower the light utilization efficiency. Therefore, when the directivity of R, G, B is different for each wavelength band as in the present embodiment and the converging angle δ = φ is smaller on the longer wavelength side,
The ratio of the projected light flux tends to be a distribution in which long-wavelength light is relatively reduced as compared with the spectral distribution of light emitted from the light source.

Therefore, it is preferable that the emission spectrum of the lamp used as the light source for projection has a low color temperature containing a relatively large amount of R component. Specifically, the color temperature is 30
A lamp having an emission spectrum of 00K to 7000K is effective.

In particular, when a halogen lamp having a low color temperature is used as the light source for projection, the color temperature of the secondary radiation light source light and the projected image light is increased to improve the white color close to a natural color.

In FIG. 6, R (red), G (green), B (blue)
Occupied areas K _R , K _G , and K _B for the three colors
But,

[0107]

(Equation 7)

R, G, B to satisfy the magnitude relation of
A three-color transmission type interference filter is used. The spectral transmittance is schematically shown in FIG. Although FIG. 6 shows an example in which the filter is divided into 6 by combining RGB, other numbers may be used.
It is preferable that the number of divisions is large because the light amount distribution over the entire screen can be made more uniform. Even with a small number of divisions, a diffusion image of light in the optical path of the Schlieren optical system can effectively produce a projection image without any problem. Practically, about 6 to 18 divisions can be used. More preferably, 12 to 18 divisions are used.

The filter used for such a purpose is
Since high heat resistance and light resistance are required, it is preferable to use a dielectric multilayer interference filter that is a transflective filter rather than a light absorption filter. In this case, since the color separation characteristic and the transmittance are superior to those of the light absorption type filter, the spectral filter has high color purity.

The dielectric multilayer interference filter is formed by alternately stacking dielectric films having different refractive indexes on the substrate by a vacuum deposition method or a sputtering method. In addition, FIG.
The patterning of the RGB filter as described above can be formed by a conventional technique such as a mask vapor deposition method or lift-off in which the underlying copper film is used as a resist.

As another filter configuration, as shown in FIG. 8, a part of the opening radially reflects only R, an interference filter that transmits BG and an interference filter that reflects only RG and transmits B, and the remaining filter. The region (W) may form a transmission surface that transmits the entire wavelength range, and may satisfy the magnitude relationship of the expression (7). The spectral transmittance is shown in FIG.

The filter used does not necessarily have to be radial with the optical axis as the axis of symmetry, and stripes as shown in FIG. 10, lattice (zigzag mosaic) as shown in FIG. It may be a spotted shape (circular shape) as shown, or a donut shape having a complete opening in the central portion as shown in FIG. In either case, the occupied areas K _R , K _G , and K _B for the three colors of RGB may be configured to satisfy the magnitude relationship of Expression (5). Further, the opening shape does not have to be circular and may be rectangular.

In the filter of the present invention, a glass substrate on which a dielectric multilayer interference filter is formed may be provided in the optical path, or the surface of the cone-shaped prism 3 in the light source optical system on the light emission side ( It may be formed on a conical surface or a flat surface). Further, a light absorption type filter may be used as long as it is within the allowable range in terms of heat resistance and light resistance.

In order to secure high directivity of the light from the light source, it is preferable to use a cone (conical prism or cone reflector), but a lens array or diffuser plate is installed instead of the cone. May improve the uniformity of the projected light. When a cone is used, light source light having a light collection angle of 2 ° to 10 °, preferably 6 ° to 10 ° can be obtained. A major feature is that both high light source light utilization efficiency and high directivity can be achieved at the same time.

In the present embodiment, the structure in which the transmitted light of the filter provided in the optical path is used is shown, but a reflection type color separation filter (dichroic mirror) may be used. For example, as shown in FIG. 14, the occupied areas K _r , K _g , and K _b of the regions r, g, and b for the respective colors of the dichroic mirror that reflect the respective colors of RGB satisfy the magnitude relation of the expression 7. Used for. The spectral reflectance is shown in FIG. The reflection type uses less light loss and further improves the light utilization efficiency of the entire system.

In this case, instead of the cone-shaped prism, as shown in FIG.
4, a cone-shaped reflector (convex apex angle α2 = 165
°, bottom cross-sectional diameter 30 mm, height 12 mm, but the height of the conical reflector of the inclined surface is 1.97 mm), and the above dichroic mirror is formed on the inclined surface (conical surface).

Further, a cold mirror which transmits / absorbs infrared rays and ultraviolet rays and reflects only visible light occupies most of the openings, and a color separation filter which partially transmits or absorbs only R and transmits or absorbs only RG is provided. It may be formed.

Also in the case of such a reflection type color separation filter (dichroic mirror), a dichroic mirror may be formed on the surface of the cone-shaped reflector, the lens array or the diffuser plate.

As a result, according to the present invention, the dependence of the contrast ratio of the projected image on the wavelength is reduced, and even when a single transmission / scattering type liquid crystal display element is used, the color shift from the dark level to the bright level is achieved. It is possible to efficiently obtain a projected image having a black-and-white gradation with a small number of pixels, and achieve a projected image with a high contrast ratio and a high brightness and high uniformity.

In the present embodiment, a mosaic RG is formed for each pixel on the counter electrode substrate of the transmission / scattering type liquid crystal display element.
By using the color liquid crystal display element having the B color filter formed thereon, a projection type color display device using a single transmission / scattering type display element can be realized with the above-mentioned characteristic improvement.

Comparing with the same aperture area of the aperture, in the present embodiment, the light source light is lost by about 1/3 in the filter portion as compared with the case where the filter is not used.
However, when the filter of this embodiment is used, the aperture diameter is increased to increase the total amount of light, and high directivity in the light in the wavelength range corresponding to each divided area is ensured.

For example, under the condition of a certain diagonal size liquid crystal display element and other optical elements, an aperture diameter of about 1.5 cm (first 1 stop). When the filter of this embodiment is arranged, the opening diameter is increased by setting it to about 1.7 cm. Then, the total amount of light can be made approximately the same, and the light collection angle can be made equal or larger.

(Example 2) In Example 1, instead of a single transmission / scattering type display element, three transmission / scattering type liquid crystal display elements having LCPC layers of the same specifications (three are almost the same standard). Which have almost the same characteristics) are used for each color of RGB. FIG. 16 shows the overall system configuration of the projection display device 20.

The light emitted from the light source optical system includes two types of dichroic mirrors 141a used as a color separation / combination system.
After being separated into three colors of B, G, and R by 141b,
The light is incident on each of the first condenser lenses 131B, 131G, and 131R and becomes substantially parallel light.

The non-scattered light that has passed through the liquid crystal display elements 15B, 15G and 15R is the second condenser lenses 132B and 132.
G and 132R collect the light at the position of the projection lens 19 and project it on a screen (not shown) by the projection optical system lens, but scattered light is removed by the second diaphragm 18 and is not projected on the screen. The other configurations are similar to those of the first embodiment.

Further, in the optical system of the projection type display apparatus 100 of FIG. 22 shown as a conventional example, the first filter 1 and the first filter 1 of the present invention are provided near the first diaphragm 17 and near the second diaphragm 18, respectively. Two filters 2 may be further installed.

As described above, by using the filter in combination with the system configuration using three transmission / scattering type display elements having the same structure, the brightness is improved as compared with the conventional example, and the single plate type mosaic color filter is used. It is possible to realize a projection type color display device in which the definition of the display element is kept higher than that of the panel.

Even if the transmission-scattering type display elements having the same structure are used, the difference in the contrast ratio due to the difference in the colors of RGB is reduced, so that it is not necessary to form the display elements for each wavelength. In this case, mass production of a single product is possible, which is an advantageous system configuration.

In this embodiment, instead of the dichroic mirror with an incident angle of 45 ° which is usually used as a color separation / synthesis system, the incident angle is set to about 30 ° in order to improve the light utilization efficiency without reducing the color purity. Although the dichroic mirrors are arranged as described above, the dichroic mirrors having an incident angle of 45 ° may be arranged as in the conventional case.

Further, by using at least a first filter having a spectral characteristic as shown in FIG. 7 or FIG. 15, the color purity in the RGB wavelength range of the light source light can be regulated, so that the color separation / synthesis optical system can be defined. The color separation / synthesis wavelength accuracy of the dichroic mirror used in the system is relaxed. In particular, 570 which causes deterioration of color purity of G and R
By removing the yellow light in the wavelength range of ˜590 nm with the first filter, a high color purity of G · R is achieved.

Example 3 A reflective liquid crystal display element is obtained by forming a light reflection layer on the side opposite to the light incident side of the transmission / scattering type liquid crystal display element in Example 1. Specifically, the ITO transparent electrode formed for each pixel is used as a reflective electrode, and light is incident from the counter electrode side. The reflective electrode may be a metal film of aluminum, silver, or the like, or a translucent dielectric film having a different refractive index is alternately changed by changing the refractive index (large refractive index / small refractive index) depending on the thickness of the light wavelength order. A dielectric multilayer mirror having a laminated structure may be used.

Using such a reflective display element, as shown in FIG.
A projection type display device 30 as shown in FIG. 18 is manufactured.
The incident light is 2 with respect to the vertical line of the reflective surface of the reflective liquid crystal display
The light emitted from the optical system of the light source advances along the optical axis ax by being incident with an inclination of about 10 ° (tilt angle), and is condensed by the condenser lens 13 on the reflective liquid crystal display element 15. This incident light is normally reflected by the reflecting surface of the liquid crystal display element 15 (its incident angle is τ), passes through the condenser lens 13 again, and an image conjugate with the first aperture stop 17 of the light source optical system is formed. An image is formed at a position that does not overlap the first aperture stop 17. The second diaphragm 18 is arranged at this conjugate image position.

Here, the filters arranged in the vicinity of the first aperture stop 17 and the second aperture stop 18 are the same as in the first embodiment, and various forms can be used. In addition, in order to avoid unnecessary superimposition of interface reflection on the projected image, an antireflection film or fine irregularities are formed on the ITO electrode surface of the counter substrate, and a condenser lens is bonded to the counter substrate to eliminate the interface. It is preferable to reduce interface reflection.

By using the transmissive / scattering type liquid crystal display element 15 of the reflective type, light reciprocates through the LCPC layer, so that the scattering ability is dramatically improved as compared with the transmissive type, and as a result, the contrast ratio of the projected image is increased. Is improved.

As in the first embodiment, a full color projection display device using a single transmission / scattering liquid crystal display element is used by using a color display element in which a mosaic RGB color filter is formed for each pixel. 30 can be realized.

Example 4 In the optical system of Example 3,
Instead of a single reflection-type transmission / scattering type display element, three reflection-type transmission / scattering type liquid crystal display elements having the same configuration are used.
Used for each color of GB. The overall structure of the projection type display element 40 is shown in FIG.

The light emitted from the light source optical system is used as two types of dichroic mirrors 144 and 1 used as a color separation / synthesis system.
After being color-separated into three colors of R, G, and B by 45, they are incident on the condenser lenses 13B, 13G, and 13R, respectively, and become substantially parallel light.

The non-scattered light which passes through the liquid crystal display elements 15B, 15G and 15R having the reflective layer on the back surface and having the transmission / scattering type operation mode after being reflected and reciprocated through the condenser lens 13B,
13G and 13R collect the light at the position of the projection lens 19 and project it on a screen (not shown) by a projection optical system lens (not shown), but scattered light is removed by the second diaphragm 18 and is not projected on the screen. .

Further, the diagonal length of the display portion of the reflection type liquid crystal display element 15 is two sizes (inch), and the elliptic mirror 12a (first focal length f1 = 20 mm, second focal length f
2 = 100 mm, total depth H = 25 mm) and spherical mirror 12
b (curvature radius R = 45 mm, display element side opening diameter DQ = 4
5 mm) is used, and it is arranged so that the center of curvature of the spherical mirror coincides with the first focus of the elliptical mirror.

The convex cone-shaped prism 3 (vertical angle 130
°, bottom cross-section diameter 40 mm, height 12 mm, but the height of the inclined surface of the conical prism 3 is 9.33 mm), and the first filter 1 is provided on the conical surface on the exit surface side. Further, the second filter 2 is arranged after the second diaphragm 18. Other configurations are substantially the same as those in the third embodiment.

By adopting the structure using the three transmission / scattering type display elements having the same structure, the brightness is improved and the definition of the display element is kept high as compared with the third embodiment.

In particular, in the light source optical system, if the condenser mirror is a compound mirror of an elliptic mirror and a spherical mirror, the condenser efficiency is further improved and the brightness of the projected image is increased as the whole system.

In this embodiment, a dichroic mirror with an incident angle of 45 °, which is usually used as a color separation / combination system, is used.
Instead of the incident dichroic prism, the dichroic mirror is arranged so that the incident angle is about 30 ° in order to improve the light utilization efficiency without reducing the color purity. A configuration using a dichroic prism or the like may be used.

Example 5 In the optical system of Example 1,
Instead of the active matrix substrate, two substrates each having an ITO transparent electrode formed on the entire surface are used to fabricate a cell to obtain a transmission / scattering shutter. Then, instead of the projection lens, a bundle of fibers formed by bundling optical fibers is arranged immediately after the second diaphragm 18. Other configurations are the same as those of the first embodiment.

The present invention also provides various filters that can be used in the above-mentioned projection type display device. It can be applied to various LCSM-LCDs and other transmission / scattering type display elements by changing the area and patterning arrangement of the region corresponding to each wavelength region.

Further, by using the projection type display device of the present invention as one optical device for an illumination device, a high-speed light control device with little change in color temperature can be obtained. Further, as in the third embodiment, a reflection type transmission / scattering type shutter may be used to provide an illumination device.

[0147]

In the projection type display device of the present invention, the wavelength dependence of the contrast ratio of the projected image is reduced even though the single or plural transmission / scattering type liquid crystal display elements having the same element structure are used. It is reduced and high color reproducibility is achieved.

Further, as compared with the projection type display device using the conventional transmission / scattering type display element, higher light utilization efficiency can be obtained with the same contrast ratio, and higher contrast can be obtained with the same light utilization efficiency. The ratio is obtained.

Further, the RGB of the color separation filter of the filter
By appropriately setting the spectral characteristics, it is possible to correct the emission spectrum of the light source, which can improve the color purity.

The effect of the first embodiment is that a single-panel panel is used, so that a small projection type display device can be obtained.

The effect of the second embodiment is that the bright projection type display device can be obtained without lowering the definition of the image because the three panels are used.

Since the single plate reflection type panel is used, the effect of the third embodiment is higher than that of the transmission type panel, and a brighter projection type display device can be obtained with the same brightness or the same contrast ratio. To be

The effect of the fourth embodiment is that, since the three-plate reflection type panel is used, a bright projection type color display device can be obtained without lowering the definition of the image.

The present invention can be used in various other applications as long as the effect is not lost. For example, a laser shutter using a liquid crystal optical element or a photoconductive material is used as a reflective LCS.
It can be used in a spatial light modulator (SLM or the like) used as an image writing medium of an M-LCD.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a first example of a positional relationship between a display element of the present invention and a condenser lens.

FIG. 2 is a schematic diagram showing a second example of the positional relationship between the display element of the present invention and a condenser lens.

FIG. 3 is a schematic diagram showing a third example of the positional relationship between the display element of the present invention and a condenser lens.

FIG. 4 is a schematic diagram showing a fourth example of the positional relationship between the display element of the present invention and a condenser lens.

FIG. 5 is a schematic diagram showing Embodiment 1 of the projection type display device of the present invention.

FIG. 6 is a plan view of a first example of a filter according to the present invention.

FIG. 7 is a graph showing a spectral transmittance characteristic of the filter of the first example.

FIG. 8 is a plan view of a second example of the filter according to the present invention.

FIG. 9 is a graph showing the spectral transmittance characteristics of the filter of the second example.

FIG. 10 is a plan view of a third example of the filter according to the present invention.

FIG. 11 is a plan view of a fourth example of the filter according to the present invention.

FIG. 12 is a plan view of a fifth example of the filter according to the present invention.

FIG. 13 is a plan view of a sixth example of the filter according to the present invention.

FIG. 14 is a plan view of a seventh example of a filter according to the present invention.

FIG. 15 is a graph showing the spectral transmittance characteristics of the filter of the seventh example.

FIG. 16 is a schematic diagram showing Embodiment 2 of the projection type display device of the present invention.

FIG. 17 is a schematic plan view of Example 3 of the projection type display device of the present invention.

FIG. 18 is a schematic side view of Example 3 of the projection type display device of the present invention.

FIG. 19 is a schematic view of Example 4 of the projection type display device of the present invention.

FIG. 20 is a graph showing the spectral characteristics of a liquid crystal display device including a liquid crystal solidified composite when a conventional projection display device is used.

FIG. 21 is a graph showing the wavelength dependence of the contrast ratio of a transmission / scattering type display element when a conventional projection type display device is used.

FIG. 22 is a schematic view showing a projection type display device of a conventional example.

FIG. 23 is a graph showing the wavelength dependence and the converging angle dependence of the contrast ratio when a conventional transmission / scattering projection display device is used.

FIG. 24 is a schematic diagram showing a light source optical system in Example 5 of the projection type display device of the present invention.

[Explanation of symbols]

 1, 2: Filters 3: Conical prisms 4: Conical reflectors 10, 20, 30, 40, 50: Projection type liquid crystal display device 11: Light source 12, 12A: Elliptical mirror 12B: Spherical mirror 13: Condenser lens 15: Liquid crystal display element 17: First diaphragm 18: Second diaphragm 19: Projection lens

Claims (8)

[Claims] 1. A light source optical system including a light source, a transmission / scattering type liquid crystal display element, and a projection optical system are provided, and the light source optical system, the liquid crystal display element, and the projection optical system constitute a Schlieren optical system. It is a projection type display device in which the light emitted from the light source is passed through the liquid crystal display element and then projected from the projection optical system.A virtual light source is set in the optical path from the light source to the liquid crystal display element. The filter is arranged at the position of the virtual light source, the light passage surface of the filter has a plurality of regions, and at least one region allows only a certain wavelength region of light to pass. A projection type display device characterized in that a liquid crystal display element is arranged at a non-imaging position of a virtual light source in an optical path to reach. 2. A light source optical system including a light source, a transmission / scattering type liquid crystal display element, and a projection optical system are provided, and the light source optical system, the liquid crystal display element, and the projection optical system constitute a Schlieren optical system. It is a projection type display device in which the light emitted from the light source is passed through the liquid crystal display element and then projected from the projection optical system.A virtual light source is set in the optical path from the light source to the liquid crystal display element. The first filter (1) is arranged at the position of the virtual light source, the light passing surface of the first filter (1) has a plurality of regions, and at least one region has only a certain wavelength band of light. Further, the liquid crystal display element is arranged in the optical path from the virtual light source to the projection optical system at the non-imaging position of the virtual light source, and further in the optical path after the liquid crystal display element. At the image forming position of the filter (1) Filter (2) projection display apparatus characterized by is disposed. 3. A light source optical system, a transmission / scattering type liquid crystal display element (15) and a projection optical system are provided, and light source light emitted from the light source optical system is passed through the liquid crystal display element (15). A projection type display device that is subsequently projected from a projection optical system, wherein the light source optical system includes a light source (11), an elliptical mirror (12) and a first diaphragm (17). Of the light source (11) near the position of the first focus of the first ellipsoidal mirror (12), and the first stop (17) near the position of the second focus of the elliptical mirror (12). 17) further arranged near the light passage surface of the first filter (1) to form a plurality of regions s _X (X
= 1 to n, n ≧ 2), at least one region of which allows only a certain wavelength region of light to pass therethrough, and a first filter (corresponding to a wavelength region in which the liquid crystal display element (15) has a low scattering ability ( It is provided so that the effective aperture area of the region 1) is relatively smaller than the effective aperture area of the region of the first filter (1) corresponding to the wavelength range with high scattering power. A condenser lens (13, 131, 132) is provided in front of or behind the liquid crystal display element (15) in the optical path leading to the system, or both in front of and behind the liquid crystal display element (15), and passes through the first diaphragm (17). The diffused light generated by the condenser lens (1
3, 131, 132), a conjugate image of the first diaphragm (17) is formed at almost the pupil position of the projection optical system, and the second diaphragm (18) is formed near the image plane. The second aperture (18) is provided so that the aperture shape of the second aperture (18) substantially coincides with the conjugate image of the first aperture (17), and the second filter (2) includes the second aperture (18). And a plurality of regions s _Y (Y = 1 to n, n ≧ 2) provided on the light passage surface of the second filter (2) in the vicinity of
And a liquid crystal display device (1
5) and a projection type display device, which allows only a certain wavelength range of light passing through the second diaphragm (18) to pass therethrough. 4. The projection type display device according to claim 2 or 3, wherein the first filter (1) or the second filter (2) has a light passage surface, or the first filter (1) and the second filter (2). _A region s _A that allows only the wavelength region A having a center wavelength of λ _A to pass through both light passage surfaces of the filter (2).
And a region s _B that allows only the wavelength region B having the center wavelength λ _B to pass.
And the areas occupied by the regions s _A and s _B on the light passage surface are K _A and K _B , respectively, 0.5 ≦ (K _A / K _B ) ^0.5 × (λ _A / λ _B ) ≦ A projection type display device, characterized in that the structure satisfies the relationship of 1.5. 5. The projection display device according to claim 2, wherein either the first filter (1) or the second filter (2), or the first filter (1) and the second filter are used. Both (2) are provided with regions corresponding to three wavelength regions of R (red), G (green), and B (blue), and the effective aperture areas K _R , K _G , and K _{B of} each region are liquid crystal display elements. A projection-type display device characterized in that it is changed according to the scattering power of the. 6. The projection type display device according to claim 5, wherein R (red), G (green) and B (blue) of the second filter (2).
The aperture shapes of the respective regions corresponding to the three wavelength regions of are the R (red), G (green), and B (blue) of the first filter (1).
The projection type display device is provided so as to substantially match the conjugate image of the aperture shape of each region corresponding to the three wavelength regions. 7. The projection type display device according to claim 1, wherein the regions divided according to the wavelength range of light passing through the filter are fan-shaped, and are arranged substantially radially as a whole. A projection-type display device, characterized in that the filtered filter is used. 8. The projection type display device according to claim 1, wherein the liquid crystal display element has a substrate with electrodes, and nematic liquid crystal having positive dielectric anisotropy is dispersed and held in a solidified matrix. Ordinary refractive index (n ₀ ) of a liquid crystal having a liquid crystal solidified substance composite and using the refractive index of the solidified substance matrix
A projection type display device, which is a transmission / scattering type liquid crystal display element matched with the above.