JP2007101648A - Reflection type liquid crystal display element, method for manufacturing the same, and reflection type liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily manufacturing a reflection type liquid crystal display element by using interference light, and to provide a reflection type liquid crystal display device that uses the element. <P>SOLUTION: The reflective liquid crystal display element is obtained, by applying a sealing material in a ring region around the display region of a liquid crystal display element portion formed on a single crystal silicon substrate, having a reflective electrode on its upper face and laminating a glass substrate, having a transparent electrode formed on one surface with the sealing material, wherein transparent oxide films are formed to the thickness in terms of λ=4nd, corresponding to respective wavelengths λ of R (red), G (green) and B (blue) on the reflection type electrode on the single-crystal silicon substrate. The display element is manufactured by first forming a transparent oxide film of the film thickness, corresponding to a R filter, dry etching the transparent oxide film over a pixel, corresponding to B to a predetermined film thickness, while the transparent oxide film over pixels corresponding to R and G is masked, and dry etching the transparent oxide film over a pixel corresponding to G to a predetermined film thickness, while the transparent oxide film over pixels corresponding to T and B is masked. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reflective liquid crystal display element, a manufacturing method thereof, and a reflective liquid crystal display device.

  A liquid crystal display element in which a circuit network necessary for a liquid crystal display element is formed on the surface of a single crystal silicon substrate and liquid crystal is sandwiched between the single crystal silicon substrate and a transparent substrate is used as an LCOS (Liquid Crystal On Silicon). This is a display element that is advantageous for miniaturization and high definition, and is used in liquid crystal projectors and viewfinders. Conventionally, color display of a liquid crystal display element has been realized by mounting a color filter on a liquid crystal cell, so in LCOS, it has a layer structure of a color filter, a transparent substrate, a liquid crystal, a reflective electrode, and a liquid crystal drive circuit from the top. Yes.

  FIG. 4 is a sectional view of a reflective liquid crystal display device according to the prior art. A reflection substrate comprising a silicon substrate 5 having a reflective electrode 6 on the upper surface and a glass substrate 3 having a transparent electrode formed on the entire surface, bonded to each other via a sealing material 4 applied in an annular manner to the outer periphery of the display area of the liquid crystal display element portion. The color filter 1 is bonded to a type liquid crystal panel, and the color filter 1 includes a red filter 2R, a green filter 2G, a blue filter 2B, and a black matrix.

  The reflective liquid crystal panel is mounted on a substrate having an electrical wiring pattern such as a flexible substrate, the display pixels of the reflective liquid crystal panel and the pixels of the color filter are accurately aligned, and attached to the upper surface of the reflective liquid crystal panel.

  In the structure as shown in FIG. 4, the aperture ratio is limited by the black matrix formed in the color filter, and the luminance is lowered due to the light absorption of the color filter. In addition to these functional problems, as a manufacturing problem, it is necessary to precisely align each display pixel of the reflective liquid crystal panel and the pixel of the color filter, and when the color filter is bonded, the reflective liquid crystal Problems such as air accumulation or dust entering between the panel and the color filter occur.

  A color liquid crystal display element that does not use a color filter has been developed as a color liquid crystal display element that eliminates the above-described drawbacks. For example, it is a reflection type liquid crystal display element using interference light, and light whose light path difference between light reflected from the reflection plate and light reflected on the thin film is an integral multiple of the wavelength is strengthened. Conversely, light other than an integral multiple uses light interference that is weakened. (For example, Patent Document 1)

JP 2002-122894 A

  An easy manufacturing method of a reflective liquid crystal display element using interference light and a reflective liquid crystal display device using the same are provided.

  At least, a sealing material is annularly applied to the outer periphery of the display region of the liquid crystal display element portion formed on the single crystal silicon substrate having a reflective electrode on the upper surface, and a glass substrate having a transparent electrode formed on one surface is interposed through the sealing material. In the reflective liquid crystal display element bonded to the single crystal silicon substrate, the wavelengths of R (red), G (green), and B (blue) are set on the reflective electrode on the single crystal silicon substrate with λ = 4nd. A reflective liquid crystal display element having a transparent oxide film having a thickness corresponding to λ is formed. Here, n is the refractive index of the oxide film, and d is the thickness of the transparent oxide film.

  At least a step of forming a plurality of liquid crystal display element portions in a matrix at a predetermined distance on a single crystal silicon mother substrate, and each wavelength of R, G, and B with λ = 4nd on the reflective electrode of the liquid crystal display element portion a step of forming a transparent oxide film having a thickness corresponding to λ, a step of applying a sealing material to the outer periphery of the display region of the liquid crystal display element portion, a glass mother substrate having a transparent electrode formed on one surface, and the single crystal silicon Manufacturing of a reflective liquid crystal display device comprising a step of bonding a mother substrate through the sealing material, a step of dividing the mother substrate into individual liquid crystal display device portions, and a step of injecting and sealing liquid crystal into the individual liquid crystal display device portions The method.

  A step of forming a transparent oxide film having a thickness corresponding to the filter of R, a mask on the pixels corresponding to R and G of the transparent oxide film, and a transparent oxide film on the pixel corresponding to B being a predetermined film Production of a reflective liquid crystal display device comprising a step of dry etching to a thickness and a step of performing a dry etching to a predetermined thickness of a transparent oxide film on a pixel corresponding to G by masking the pixel corresponding to R and B The method.

  At least a circuit board, the reflective liquid crystal display element mounted on the circuit board with a display surface facing upward, a light emitting element mounted on the circuit board and emitting light on the circuit board surface, and an upper surface of the light emitting element A light guide plate arranged to be positioned, a diffusion member and a polarizing plate arranged in front of the inner side surface of the light guide plate, and reflecting light emitted in parallel to the circuit board from the polarizing plate, A casing incorporating a transflective reflection sheet disposed in front of the parallel light so as to enter the reflective liquid crystal display element, and the casing is mounted on top of the reflective liquid crystal display element; A reflection type liquid crystal display device.

  In the present invention, since a color of R (red), G (green), and B (blue) is realized only by adjusting the thickness of the transparent oxide film formed on the reflective electrode, a display with a high aperture ratio and a high luminance is achieved. realizable.

  In the invention of claim 4, since the light incident on the reflective liquid crystal display element becomes vertical, a clear image can be obtained.

  At least, a sealing material is annularly applied to the outer periphery of the display region of the liquid crystal display element portion formed on the single crystal silicon substrate having a reflective electrode on the upper surface, and a glass substrate having a transparent electrode formed on one surface is interposed through the sealing material. In the reflective liquid crystal display element bonded to the single crystal silicon substrate, the wavelengths of R (red), G (green), and B (blue) are set on the reflective electrode on the single crystal silicon substrate with λ = 4nd. A reflective liquid crystal display element having a transparent oxide film having a thickness corresponding to λ is formed, and the manufacturing method thereof is to first form a transparent oxide film having a film thickness corresponding to the R filter, A mask is formed on the pixel corresponding to G and G, and the transparent oxide film on the pixel corresponding to B is dry-etched to a predetermined thickness, and the mask corresponding to R and B is masked on the pixel corresponding to G. A transparent oxide film with a predetermined thickness The manufacturing method is dry etching.

  FIG. 3 is a diagram for explaining the principle of the present invention. In FIG. 3, d is the thickness of the transparent oxide film 8, and n is the refractive index of the transparent oxide film 8. When the parallel incident light 7 having the wavelength λ is incident on the transparent oxide film 8 at an incident angle i, the 2nd cosj between the reflected light 7a reflected by the upper surface of the transparent oxide film 8 and the reflected light 7b reflected by the reflective electrode 6 is 2nd cosj. An optical path difference of (i + j = 90 degrees) occurs. The transparent oxide film 8 is, for example, titanium oxide having a refractive index of 2.4, and the liquid crystal has a refractive index of about 1.5. Since the transparent oxide film 8 is in contact with the liquid crystal on the upper surface, the phase of the light reflected on the upper surface of the transparent oxide film 8 is inverted by reflection from the fixed end. That is, the wavelength is shifted by 1/2. Therefore, when the optical path difference is λ / 2, the reflected light is strengthened by interference. Expressing this in the equation, λ / 2 = 2nd cosj. In the reflection type liquid crystal display element, since light enters the liquid crystal display element perpendicularly, j = 90 degrees, and the above formula is λ / 2 = 2nd (λ = 4nd). That is, R, G, and B can be realized by selecting the transparent oxide film thickness d corresponding to each wavelength λ of R, G, and B.

  FIG. 1 is a diagram for explaining the principle of the present invention. A silicon substrate 5 having a reflective electrode 6 on the upper surface and a glass substrate 3 on which a transparent electrode (not shown) is formed on one surface are pasted via a sealing material 4 that is applied annularly to the outer periphery of the display area of the liquid crystal display element portion. In the reflection type liquid crystal display device formed in combination, a transparent oxide film 8 is formed on the reflective electrode 6 in red 8R, green 8G, and blue 8B for the three primary colors. The thicknesses of the transparent oxide films 8R, 8G, and 8B can be obtained from the R, G, and B wavelengths λ according to the previous equation. Each wavelength is, for example, R = 660 nm, G = 520 nm, and B = 450 nm.

  FIG. 2 is a side cross-sectional view of each step for explaining a method for producing a transparent oxide film of a reflective liquid crystal display device according to the present invention. In step (A), a transparent oxide film 8 having a film thickness corresponding to the R filter requiring the thickest transparent oxide film is formed on all the pixels of the liquid crystal display element portion formed on the single crystal silicon substrate 5 in the step (A). In (B), a mask 9 is first formed on the pixels corresponding to R and G, and the transparent oxide film 8 on the pixels corresponding to B is dry-etched to a predetermined thickness. Next, in step (C), the mask 9 is formed on the pixels corresponding to R and B, and the transparent oxide film 8 on the pixels corresponding to G is dry-etched to a predetermined film thickness. In step (D), the mask 9 is removed. Since the transparent oxide film 8 on the pixel corresponding to R is already a predetermined thickness at the time of film formation, there is no need for etching. Thus, transparent oxide films 8R, 8G, and 8B corresponding to the three primary colors are completed.

  FIG. 1 is a cross-sectional view of one reflective liquid crystal display element (actually, a large number of R, G, and B are formed to form a display element). In normal mass production, it is integrally formed between a pair of mother substrates. Dividing the plurality of liquid crystal display element portions to manufacture a plurality of independent liquid crystal display elements is generalized as a method for manufacturing a liquid crystal display element.

  FIG. 5 is a front sectional view of a reflective liquid crystal display device according to the present invention. The reflective liquid crystal display device 10 is for viewing images from the direction of the eyes 17 shown in the figure. Light (arrow A) from the light emitting element 12 is introduced into the light guide member 13 from the lower surface of the light guide member 13. The introduced light is diffused by the diffusing member 14 disposed in front of the inner surface of the light guide member 13, and only linearly polarized light (hereinafter referred to as P wave) transmitted through the polarizing plate 15 proceeds in the direction of arrow B. The transflective reflection sheet 16 reflects the P wave, and the P wave reflected by the transflective reflection sheet 16 advances to the arrow C, and is reflected on the reflective liquid crystal display element 11 placed on the circuit board 18. A transflective reflection sheet 16 is arranged so as to be incident. Reference numeral 19 denotes a housing.

  The reflective liquid crystal display element 11 is arranged so that the P wave passes through the liquid crystal as it is in the power-off state, and the P wave reflected by the reflective liquid crystal display element 11 proceeds in the direction of the arrow. The polarizing plate 16b of the transflective reflection sheet 16 is disposed so as not to transmit the P wave, and is in a black display state when the power is off.

  In the power-on state of the reflective liquid crystal display element 11, the P wave is polarized by the liquid crystal, and the polarized light polarized and reflected by the reflective liquid crystal display element 11 travels in the direction of the arrow. Since the polarizing plate 16b of the transflective reflection sheet 16 is disposed so as to transmit the light reflected in the power-on state, it proceeds in the arrow direction D, so that the white display state is obtained in the power-on state.

  Color display is performed by turning on / off the R, G, and B elements of the reflective liquid crystal display element. However, in this embodiment, since the light entering the eyes 17 is perpendicular to the reflective liquid crystal display element 11, a clear image is obtained. can get.

The figure for demonstrating the principle of this invention Side surface sectional drawing of each process for demonstrating the manufacturing method of the transparent oxide film of the reflection type liquid crystal display element by this invention The figure for demonstrating the principle of this invention Cross-sectional view of a reflective liquid crystal display device according to the prior art Front sectional view of a reflective liquid crystal display device according to the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color filter 2R Red filter 2G Green filter 2B Blue filter 3 Glass substrate 4 Sealing material 5 Silicon substrate 6 Reflective electrode 7 Incident light 7a Reflected light 7b Reflected light 8 Transparent oxide film 8R Transparent oxide film for red 8G Transparent oxide film for green 8B Blue transparent oxide film 9 Mask 10 Reflective liquid crystal display device 11 Reflective liquid crystal display element 12 Light emitting element 13 Light guide member 14 Diffusing member 15 Polarizing plate 16 Transflective reflective sheet 16b Polarizing plate 17 Eye 18 Circuit board 19 Housing

Claims (4)

  At least, a sealing material is annularly applied to the outer periphery of the display region of the liquid crystal display element portion formed on the single crystal silicon substrate having a reflective electrode on the upper surface, and a glass substrate having a transparent electrode formed on one surface is interposed through the sealing material. In the reflective liquid crystal display element bonded to the single crystal silicon substrate, the wavelengths of R (red), G (green), and B (blue) are set on the reflective electrode on the single crystal silicon substrate with λ = 4nd. A reflective liquid crystal display element, wherein a transparent oxide film having a thickness corresponding to λ is formed. (N is the refractive index of the oxide film, d is the thickness of the transparent oxide film) At least a step of forming a plurality of liquid crystal display element portions at a predetermined distance in a matrix on a single crystal silicon mother substrate;
Forming a transparent oxide film having a thickness corresponding to each of the wavelengths λ of R, G, and B with λ = 4nd on the reflective electrode of the liquid crystal display element portion;
Applying a sealing material to the outer periphery of the display area of the liquid crystal display element unit;
Bonding the glass mother substrate having a transparent electrode formed on one surface and the single crystal silicon mother substrate through the sealing material;
Dividing into individual liquid crystal display element parts;
A method of manufacturing a reflective liquid crystal display element, comprising the step of injecting and sealing liquid crystal into each liquid crystal display element part. Forming a transparent oxide film having a film thickness corresponding to the R filter;
Masking the pixels corresponding to R and G of the transparent oxide film and dry etching the transparent oxide film on the pixels corresponding to B to a predetermined film thickness;
3. The reflective liquid crystal display element according to claim 2, further comprising a step of masking the pixels corresponding to R and B and dry etching the transparent oxide film on the pixels corresponding to G to a predetermined thickness. Manufacturing method.   At least a circuit board, the reflective liquid crystal display element mounted on the circuit board with a display surface facing upward, a light emitting element mounted on the circuit board and emitting light on the circuit board surface, and an upper surface of the light emitting element A light guide plate arranged to be positioned, a diffusion member and a polarizing plate arranged in front of the inner side surface of the light guide plate, and reflecting light emitted in parallel to the circuit board from the polarizing plate, A casing incorporating a transflective reflection sheet disposed in front of the parallel light so as to enter the reflective liquid crystal display element, and the casing is mounted on top of the reflective liquid crystal display element; A reflection-type liquid crystal display device.

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