JPH09113899A - Reflection type image display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve brightness and to reduce the diameter of a projecting lens by combining flat plate type microlens arrays with a reflection type image display element. SOLUTION: A translucent panel 2 constituting the reflection type liquid crystal display element 1 is constituted by laminating the first and second microlens flat plate type arrays 11, 12. The first flat plate type microlens array 11 is provided with lens parts 14 formed by packing a high-refractive index resin into the recessed parts 13 formed on a glass substrate 12 and is so formed as to condense irradiation light by these lens parts 14. The second flat plate type microlens arrays 12 is provided with the lens parts 17 formed by packing the high-refractive index resin into the recessed parts 16 formed on a glass substrate 15 and is so formed as to refract the irradiation light transmitted through the lens parts 14 of the first flat plate type microlens array 11 perpendicular to a reflection film 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective image display device incorporated in a liquid crystal projector or a projector television (PTV) for enlarging and displaying a television screen or a computer screen.

[0002]

2. Description of the Related Art A projector using a liquid crystal display element capable of brightening a screen according to the brightness of an irradiation light source has come to be used instead of a cathode ray tube type projector. As such a liquid crystal display element, a transmissive liquid crystal display element and a reflective liquid crystal display element, in which irradiation light is incident on a liquid crystal layer on which an image is formed, and irradiation light transmitted through the liquid crystal layer is projected onto a screen through an optical system. There is.

A structure of a color projector using a reflection type liquid crystal display element will be described with reference to FIG. 8. Illumination light from a white light source 100 is incident on a dichroic prism 102 through a beam splitter 101 to make white light red. The reflected light is divided into light, blue light, and green light, and the respective irradiation lights are made incident on the reflective liquid crystal display element 103. On the other hand, each reflective liquid crystal display element 103 has a corresponding CRT 10
The image of No. 4 is projected, this image is read out as the reflected light of the irradiation light, this read-out light is transmitted through the beam splitter 101, and the composite image of each color is projected on the screen 105.

The structure of the reflective liquid crystal display element 103 is as follows.
As shown in FIG. 9, the transparent electrodes 112 and 117 are formed on the opposing surfaces of the pair of glass substrates 111 and 118.
A photoconductor layer 1 such as α-Si or CdS on
13, the light shielding layer 114 and the mirror layer 115 are formed. A liquid crystal layer 116 is sealed between this and the opposite side glass substrate 118, and cells are assembled as shown in FIG.
Apply voltage across 17.

The image projected on the CRT 104 is imaged on the photoconductor layer 113 via an imaging lens. Since the resistance of the photoconductor layer 113 changes in proportion to the light intensity of this image, the electric field applied to the liquid crystal layer 116 also changes accordingly, so that the illuminating light is emitted from the opposite surface.
The image written by the CRT image is read out as reflected light by illuminating.

[0006]

In the color projector, the liquid crystal display elements 103 and C corresponding to the three primary colors are used.
The RT 104 is required, and the entire device becomes large.
Therefore, if one liquid crystal display element 103 is sufficient, the device can be downsized.

With regard to the transmissive liquid crystal display element, Japanese Patent Laid-Open No. 4-60538 proposes to reduce the size of the device without reducing the brightness of irradiation light with one liquid crystal display element. As shown in FIG. 10, the transmissive liquid crystal display element disclosed in this publication has scanning electrodes 121a and signal electrodes 122a formed on opposing surfaces of glass substrates 121 and 122, and a glass substrate formed by spacers 123. 12
A liquid crystal 124 is filled in the gap between the first and the second 122, and a flat plate type microlens array 125 is further bonded to the glass substrate 121 on the side where the irradiation light is incident, so that the respective red, blue and green irradiation lights are signal electrodes 122a (pixels). It is intended to concentrate on the opening).

However, if the above-mentioned method is directly incorporated in the reflection type liquid crystal display element, the reflected light does not pass through the center of the lens portion of the flat plate type microlens array 125 as shown in FIG. It will be difficult.

In order to make effective use of the irradiation light, it is conceivable to arrange the lens portion and the pixels as shown in FIG. By doing so, the reflected light passes through the center of the lens portion of the flat plate type microlens array 125 as shown in FIG. However, as is clear from FIG. 12, in order for the reflected light to pass through the center of the lens portion, the pixel electrodes cannot be arranged in a straight line and must be arranged irregularly. There are great restrictions on the design of the members, and the total disadvantage is great.

[0010]

In order to solve the above-mentioned problems, the first invention of the present application is the reflection of a reflection type image display device for controlling the reflectance of the light ray incident on each pixel corresponding to the image to be displayed. A light-transmissive panel is provided on the light reading side, and the light-transmissive panel is configured by stacking first and second flat plate type microlens arrays. Irradiation light is collected on the first flat plate type microlens array. A lens portion for irradiating light is provided, and a lens portion for refracting the irradiating light is provided in the second flat plate type microlens array so that the irradiating light transmitted through the first flat plate type microlens array strikes the reflecting surface at a right angle.

In order to solve the above-mentioned problems, the second invention of the present application is such that the translucent panel provided on the reading side of the reflection type image display device is composed of a flat plate type microlens array. Forms a lens part on both sides of the glass substrate, the lens part provided at a position apart from the liquid crystal layer collects the irradiation light, and the lens part provided near the liquid crystal layer reflects the irradiation light on the reflection film. Refraction is performed so that the light hits at a right angle.

In the reflective image display device according to the present invention, a liquid crystal layer is provided between a pair of translucent panels, a reflective surface is provided on the back side of the liquid crystal layer, and the liquid crystal layer is formed by the reflective surface. The reflection type liquid crystal display device which reflects the irradiation light applied to the substrate and emits the reflected light as the reading light, or the above-mentioned transmission side to the reading side of the reflected light of a micro mirror array having a micro mirror for each pixel. A micromirror array type image display device is provided which controls the reflection pattern of the irradiation light for irradiating the micromirror array by providing an optical panel and controlling the angle of the micromirrors for each pixel.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a cross-sectional view of a reflective liquid crystal display element as a reflective image display element according to the present invention, and FIG. 2 is a view taken along the line AA of FIG.

In the reflective liquid crystal display element 1, transparent electrodes 2a and 3a are formed on opposite surfaces of a pair of translucent panels 2 and 3, and a photoconductive layer 4, a light shielding layer 5 and a reflective film 6 are formed on the transparent electrodes 3a. The liquid crystal 7 is filled in the gap between the reflective film 6 and the translucent panel 2, and the pixel electrode 8 is formed on the reflective film 6.

In the first invention of the present application, the translucent panel 2 is provided with the first and second flat plate type microlens arrays 1.
1 and 12 are laminated. In the first flat plate type microlens array 11 located on the side away from the liquid crystal 7, the concave portion 14 formed in the glass substrate 13 is provided with a lens portion 15 filled with a high refractive index resin. The second flat plate type microlens array 12 is arranged on the side close to the liquid crystal 7 so that the irradiation light can be condensed.
In this case, the concave portion 17 formed in the glass substrate 16 is provided with the lens portion 18 filled with the high refractive index resin, and the lens portion 18 is used to form the first flat plate type microlens array 11 described above.
The irradiation light transmitted through the lens portion 15 is refracted so as to vertically strike the reflection film 6.

Further, the lens portions 15 and 18 are provided so as to correspond to each other so that their optical axes are common, and the center of the pixel electrode 8 is evenly arranged at the apex position of the triangle in one region of the lens portion. It is arranged. In this arrangement, each pixel of red (R), blue (B), and green (G) is linearly arranged over a plurality of lens regions as shown by a dotted line in the figure.

As for the arrangement of the lens parts 15 and 18 and the pixel electrode 8, as shown in FIG. 3, red (R), blue (B), and green (G) pixels are arranged linearly and 1 It may be housed in one of the lens portions 15 and 18, or the contour shape of the lens portion may be square instead of hexagonal as shown in FIG.

Further, the flat plate type microlens array 1
Reference numerals 1 and 12 adjust the thickness of the glass substrates 13 and 16 by polishing in order to match the focal length and the like with the set values. When forming the lens portions 15 and 18 of the flat plate type microlens arrays 11 and 12, the glass substrate 13,
The concave portions 14 and 17 are formed by etching on the smooth surface of 16 which is not polished, and the concave portions 14 and 17 are filled with high-refractive-index resin to form the lens portions 15 and 18. Thus, by etching the smooth surface, the recess 1
By forming Nos. 4 and 17, since the etchant does not flow along the polishing scratches, it is possible to form the opening-shaped recesses that are not biased in plan view. Further, since the surface on which the concave portion is not formed is polished, fine polishing scratches remain, but since the polishing scratches are filled with the high refractive index resin as an adhesive, there is no optical problem.

In the above, the image projected on the CRT is photo-electrically converted by the photoconductor 4 and the same image as the image projected on the CRT is formed on the liquid crystal layer 7. On the other hand, as shown in FIG. 5, the irradiation lights divided into the three primary colors are at different angles from the lens portion 1 of the flat plate type microlens array 11.
Although it is incident on the light beam 5, the light is focused by the lens portion 15 and refracted by the lens portion 18 of the flat plate type microlens array 12 so as to vertically hit the reflection film 6, and the reading light reflected by the reflection film 6 is irradiated. It emits following the same optical path as the light.

Therefore, when the irradiation light enters from the center of the lens unit 15, the reflected light corresponding to the irradiation light also exits from the center of the lens unit 15, and the effective use of the irradiation light can be achieved.

FIG. 6 is a sectional view similar to FIG. 1 showing another embodiment using a liquid crystal. In this embodiment, the translucent panel 2 is composed of one flat plate type microlens array. doing. That is, the concave portions 21 and 22 are formed on both surfaces of the glass substrate 20 of the flat plate type microlens array, and the concave portions 21 and 22 are formed.
22 is filled with high refractive index resin to form lens portions 23 and 24. The operation is similar to that of the liquid crystal display element described above.

FIG. 7 is a sectional view similar to FIG. 1 showing another embodiment (digital mirror device) using a micromirror array. In this embodiment, the Si substrate 30 is etched, A part of the Si substrate 30 is left as the micro mirror 31. That is, by performing isotropic etching such that the back side of the micro mirror 31 is hollowed, a micro mirror 31 partially connected to the Si substrate 30 is manufactured, and the micro mirror 31 is tilted on the back side of the micro mirror 31. A micro mirror drive system 32 is provided.

Further, the S on which the micromirror 31 is manufactured
The glass substrate 20 is attached to one surface side of the i substrate 30 via a spacer 33. Lens parts 23 and 24 filled with a high-refractive-index resin are formed on both surfaces of the glass substrate 20, and a micro mirror 31 is tilted between the glass substrate 20 and one surface of the Si substrate 30. Space 34
Is formed.

Here, when the micro mirror 31 is not tilted, the reflected light is almost 100% returned and projected on the screen, and when the micro mirror 31 is tilted, the reflected light is tilted, and therefore passes through the lens portions 23 and 24. After that, the light quantity of the screen is reduced by the projection lens. That is, by applying an electric drive (video) signal to the micromirror drive system 32, the micromirror 31 is tilted in accordance with the signal, whereby a grayscale image is displayed on the screen.

The method of forming the lens portion of the flat plate type microlens array is not limited to the method of filling the high-refractive index resin in the recess formed by etching, and the refractive index is gradually changed by ion exchange. You may form a lens part. Further, in the diagram showing the operation of FIG. 6, the reflection type liquid crystal display element used for the single plate type projector is shown, but the reflection type liquid crystal display element according to the present invention can be incorporated in various projectors.

[0026]

As described above, according to the first invention of the present application, the light-transmissive panel on the reading side among the pair of light-transmissive panels holding the liquid crystal layer of the so-called reflective liquid crystal display element is
The first and second flat-plate microlens arrays are laminated, and the first flat-plate microlens array is provided with a lens portion that collects irradiation light, and the second flat-plate microlens array is provided with a first lens. Since the lens portion for refracting the irradiation light transmitted through the flat plate type microlens array of No. 1 so as to vertically hit the reflection film is provided, the irradiation light is condensed on the pixel electrode portion of the liquid crystal and the reflection light is irradiated. Can be read through the same optical path as

Particularly, the lens portion of the flat plate type microlens array is formed as a lens portion by forming a concave portion on a smooth surface which is not polished by etching and filling the concave portion with a high refractive index resin. Further, it is possible to carry out etching that diffuses uniformly, and it is possible to obtain an optically excellent microlens array.

Further, according to the second invention of the present application, the translucent panel on the reading side among the pair of translucent panels holding the liquid crystal layer of the reflective liquid crystal display element is constituted by a flat plate type microlens array. , This flat plate type microlens array has lens parts formed on both sides of a glass substrate, and the lens part provided at a position apart from the liquid crystal layer collects irradiation light, and the lens part provided at a position close to the liquid crystal layer. Since the irradiation light is refracted so as to hit the reflection film perpendicularly, the same effect as that of the first invention is exhibited.

Particularly in the case of the second aspect of the invention, since the lens portions are formed on both surfaces of one flat plate type microlens array, the number of parts can be reduced and the above effects can be exhibited.

[Brief description of the drawings]

FIG. 1 is a sectional view of a reflective image display device according to the present invention.

FIG. 2 is a view taken in the direction of arrows AA in FIG. 1;

FIG. 3 is a view similar to FIG. 2 showing another embodiment of the arrangement of the lens portion and the pixels.

FIG. 4 is a view similar to FIG. 2 showing another embodiment of the arrangement of the lens portion and the pixels.

FIG. 5 is a diagram showing optical paths of irradiation light and reflected light.

FIG. 6 is a sectional view similar to FIG. 1, showing another embodiment using a liquid crystal.

FIG. 7 is a sectional view similar to FIG. 1, showing another embodiment using a micromirror array.

FIG. 8 is an overall view of a projector using a conventional reflective liquid crystal display element.

FIG. 9 is a sectional view of a conventional reflective liquid crystal display device.

FIG. 10 is a cross-sectional view of a conventional transmissive liquid crystal display element used in a single-plate color liquid crystal projector.

FIG. 11 is a diagram showing a problem when a transmissive liquid crystal display device is applied to a reflective liquid crystal display device in FIG.

FIG. 12 is a diagram showing an arrangement of a lens unit and pixels which can be considered to complete the problem shown in FIG.

FIG. 13 is a diagram showing optical paths of incident light and reflected light in the case of the arrangement of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reflective liquid crystal display device, 2, 3 ... Translucent panel, 4 ...
Photoconductive layer, 5 ... Shading layer, 6 ... Reflective film, 7 ... Liquid crystal, 8 ... Pixel electrode, 11 ... First flat plate type microlens array, 1
2 ... Second flat plate type microlens array, 13, 16,
20 ... Glass substrate, 14, 17, 21, 22, ... Recessed portion, 1
5, 18, 23, 24 ... Lens part, 31 ... Micro mirror.

Claims (4)

[Claims] 1. A reflective image display element for controlling the reflectance of a light ray incident on each pixel corresponding to an image to be displayed, wherein the reflective image display element has a translucent panel on the side where the reflected light is read out. This translucent panel is formed by stacking first and second flat plate type microlens arrays, and a lens portion for converging irradiation light is provided on the first flat plate type microlens array. The flat-plate type microlens array 2 is provided with a lens portion for refracting the flat-type microlens array so that the flat-type microlens array transmits the illuminating light at right angles to the reflecting surface. Image display device. 2. A reflective image display element for controlling the reflectance of a light ray incident on each pixel corresponding to an image to be displayed, wherein the reflective image display element has a translucent panel on the side where the reflected light is read out. This translucent panel is composed of a flat plate type microlens array, and the flat plate type microlens array has lens portions formed on both sides of a glass substrate, and the lens portion provided at a position apart from the liquid crystal layer is A reflection-type image display device, which collects irradiation light and refracts the irradiation light so that the lens portion provided near the liquid crystal layer hits the reflection film at a right angle. 3. The reflective image display element according to claim 1 or 2, wherein a liquid crystal layer is provided between a pair of panels, at least one of which is the translucent panel. , A reflection type liquid crystal display element is provided on the back side of the liquid crystal layer, and the light displayed on the liquid crystal layer is reflected by this reflection surface to extract the image displayed on the liquid crystal layer as reflected light. Characteristic reflective image display device. 4. The reflection type image display device according to claim 1 or 2, wherein the reflection type image display device comprises a micromirror array having a micromirror for each pixel, and the reflection of the micromirror array. A micromirror array type in which the translucent panel is provided on the light reading side and the angle of the micromirrors is controlled for each pixel to control the reflection pattern of the irradiation light for irradiating the micromirror array to display an image. A reflection type image display device characterized by being an image display device.