JPH1020119A - Hologram color filter and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of static electricity and to prevent the adhesion of dust and intrusion of bubbles in the case where color filters are adhered to glass substrates. SOLUTION: At least one surface of hologram color filters 31 formed on the substrate 30, at least one surface of both adhesive surfaces of the hologram color filters 31 and this substrate 30 and at least one surface of both surfaces of the substrate 33 arranged opposite to the hologram color filter 31 and both surfaces of the hologram color filters 31 are subjected to an antiustatic treatment. As a result, the generation of the static electricity is prevented and the adhesion of the dust and the intrusion of the bubbles to the adhesive material 32 at the time of adhering the substrates 30 and 33 to the hologram color filters 31 are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hologram color filter, and more particularly, to the use of a hologram color filter in a liquid crystal display device or the like, to prevent dust from adhering to an adhesive surface or an exposed surface between a surface of the color filter and a substrate such as glass. The present invention relates to a hologram color filter for preventing bubbles from being mixed into an adhesive and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art The present applicant disclosed in Japanese Patent Application No. 5-12170 and the like a color filter using a hologram and a liquid crystal display using the same in order to greatly improve the efficiency of using a backlight for a liquid crystal display. Proposed a device,
The liquid crystal display device using such a hologram color filter is changed to a projection type, and a liquid crystal projection display device which displays a bright color image on a screen is also disclosed in Japanese Patent Application No. 5-242.
292, etc.

Hereinafter, a liquid crystal display device and a liquid crystal projection display device using such a hologram color filter will be briefly described. First, a liquid crystal display device using a hologram color filter of the first type will be described with reference to the sectional view of FIG. In the figure, a hologram array 5 constituting a color filter is spaced apart from a liquid crystal display element 6 which is regularly divided into liquid crystal cells 6 '(pixels) and on a light incident side of a backlight 3. On the back of the liquid crystal display element 6,
A black matrix 4 provided between the liquid crystal cells 6 'is arranged. In addition to the above, polarizing plates (not shown) are arranged on the incident side of the hologram array 5 and on the exit side of the liquid crystal display element 6. In addition, between the black matrix 4,
As in the case of the conventional color liquid crystal display device, an absorption type color filter that transmits light of colors corresponding to R, G, and B color separation pixels may be additionally arranged.

The hologram array 5 has a repetition period of R, G, and B color separation pixels, that is, a set of three liquid crystal cells 6 ′ adjacent to each other in the direction of the liquid crystal display element 6 in the plane of the paper. The micro holograms 5 'are arranged in an array at the same pitch as the repetition pitch. The micro holograms 5' are aligned with each set of three liquid crystal cells 6 'adjacent to each other in the direction of the plane of the liquid crystal display element 6, and each hologram 5' Each of the micro holograms 5 ′ corresponds to the light of the green component in the backlight 3 that enters at an angle θ with respect to the normal to the hologram array 5 and corresponds to the micro hologram 5 ′. It is formed in a Fresnel zone plate shape so that light is condensed on the liquid crystal cell G at the center of the three color separation pixels R, G, and B. The micro hologram 5 ′ has a relief type, which has no or little wavelength dependence of the diffraction efficiency.
It consists of transmission holograms such as phase type and amplitude type. Here, the fact that there is no or little wavelength dependence of the diffraction efficiency means that only a specific wavelength is diffracted and other wavelengths are hardly diffracted as in a Lippmann hologram. The diffraction grating having a small wavelength dependence of the diffraction efficiency diffracts at different diffraction angles according to the wavelength.

[0005] With such a configuration, when the white backlight 3 that enters at an angle θ with respect to the normal line from the surface of the hologram array 5 opposite to the liquid crystal display element 6 is incident, the wavelength is reduced. Accordingly, the diffraction angle of the minute hologram 5 'is different, and the light condensing position for each wavelength is dispersed in a direction parallel to the hologram array 5 surface. Among them, the red wavelength component is located at the position of the liquid crystal cell R displaying red, the green component is located at the position of the liquid crystal cell G displaying green, and the blue component is located at the position of the liquid crystal cell B displaying blue. By arranging the hologram array 5 so as to diffract and condense, each color component passes through each liquid crystal cell 6 'with little attenuation by the black matrix 4, and the color components of the liquid crystal cell 6' at the corresponding position. Color display according to the state can be performed. The angle of incidence θ of the backlight 3 on the hologram array 5 depends on the hologram recording conditions, hologram array 5
Of the hologram array 5, the distance between the hologram array 5 and the liquid crystal display element 6, and the like.

As described above, by using the hologram array 5 as a color filter, each wavelength component of a conventional backlight for a color filter can be made incident on each liquid crystal cell 6 'without waste and without absorption. Can be greatly improved.

Next, a liquid crystal display device using a hologram color filter of the second type will be described with reference to the sectional view of FIG. In the figure, a hologram color filter 10 of the second type comprises a hologram 7 and a condensing microlens array 8, and microlenses 8 'constituting the microlens array 8 perform R, G, B color separation. The pixels are arranged in an array at the same pitch as the repetition cycle of the pixels, that is, each set of three liquid crystal cells 6 ′ adjacent to each other in the direction of the paper surface of the liquid crystal display element 6. The hologram 7 is composed of parallel and uniform interference fringes acting as a diffraction grating, and is formed of a transmission hologram such as a relief type, a phase type, and an amplitude type having little or no wavelength dependence of diffraction efficiency. On the back surface of the liquid crystal display element 6, a black matrix 4 provided between the liquid crystal cells 6 'is arranged. In addition to the above, polarizing plates (not shown) are arranged on both sides of the liquid crystal display element 6. It should be noted that an absorption type color filter that transmits light of colors corresponding to R, G, and B color separation pixels is additionally arranged between the black matrix 4 as in the conventional color liquid crystal display device. You may do so.

With such a configuration, the hologram 7
When the backlight 3 is incident on the surface opposite to the liquid crystal display element 6 at an angle θ with respect to the normal line, the light is diffracted at different angles depending on the wavelength and dispersed on the exit side of the hologram 7. . Due to the microlenses 8 ′ arranged on the incident side or the exit side of the hologram 7, this dispersed light
The light is separated and focused on the focal plane for each wavelength. Among them,
The red wavelength component is diffracted and condensed at the position of the liquid crystal cell R for displaying red, the green component is diffracted and condensed at the position of the liquid crystal cell G for displaying green, and the blue component is condensed at the position of the liquid crystal cell B for displaying blue. As described above, by arranging and arranging the color filter 10,
Each color component passes through each liquid crystal cell 6 'with almost no attenuation by the black matrix 4, and a color display corresponding to the state of the liquid crystal cell 6' at the corresponding position can be performed.

In such an arrangement, as the hologram 7, a transmission hologram having uniform interference fringes and having a small wavelength dependency of diffraction efficiency, which is not a light-collecting property, can be used. And the pitch of the microlens array 8 is different from that of each liquid crystal cell 6 '.
It is three times as large as the conventional case where one microlens is arranged corresponding to each, and is characterized in that it is easy to manufacture and easy to align.

As a modification of FIG. 4, as shown in FIG. 5, the arrangement of the microlens array 8 and the liquid crystal display element 6 is as shown in FIG. Hologram 7 into micro lens array 8
Even if it is disposed in the backlight 3 so as to be substantially perpendicular to the traveling direction, each wavelength component of the backlight can be similarly incident on each liquid crystal cell 6 ′ without waste and without absorption. Thus, a color filter whose use efficiency is greatly improved can be realized.

Although the hologram 7 is actually laminated on the glass substrate, the microlens array 8 may be arranged on the opposite side of the hologram 7 from the glass substrate.

Further, a liquid crystal display device using a hologram color filter having the structure shown in FIGS. 3 to 5 can be used as it is as a direct-view type liquid crystal display device, or used as a spatial light modulator for projection display. Thus, it can be used as a liquid crystal projection display device. FIG. 6 is a cross-sectional view of the case where the liquid crystal display device of FIG. 3 is configured as a liquid crystal projection display device (the same applies to FIGS. 4 and 5). The plate 12 has a second polarizing plate 13 disposed close to or integrally with the emission side of the liquid crystal display element 6. The color liquid crystal display device 11 is illuminated by a white parallel backlight 3 from an illumination device 14 composed of a combination of a metal halide lamp 15 and a parabolic mirror 16, for example, and is modulated by the color liquid crystal display device 11. The image is enlarged by a projection lens 18 via a field lens 17 disposed near the liquid crystal display device 11 and is enlarged and formed on a screen 19, so that a bright projected image can be obtained.

In the liquid crystal display device using the hologram color filter as described above, the liquid crystal display element 6 including the black matrix 4 is actually, for example, as shown in a cross section in FIG. For example, a liquid crystal layer 25 of twisted nematic or the like sandwiched between two glass substrates 21 and 22 is provided. The inner surface of the backlight-side glass substrate 21 is uniformly transparently opposed to the black matrix 4. An electrode 23 is provided, and a transparent pixel electrode 24 and a TFT (not shown) are provided independently for each of the liquid crystal cells R, G, and B on the inner surface of the glass substrate 22 on the display surface side. An alignment layer (not shown) is also provided on the liquid crystal layer 25 side of the electrodes 23 and 24. Then, a hologram color filter 5 or 10 provided close to or adhered to the glass substrate 21 on the backlight side and provided on the surface of the substrate 26 on the side of the liquid crystal display element 6 is arranged, and the polarizing plate 12 is provided on the backlight side of the substrate 26. The polarizers 13 are attached to the outer surface of the glass substrate 22 on the viewing side of the liquid crystal display element 6, for example, and their transmission axes are arranged to be orthogonal to each other. In addition, the polarizing plate 12 on the backlight side is
Instead of attaching to the backlight side of the substrate 26, FIG.
In some cases, as shown by a dotted line inside, it may be arranged in the optical path of the backlight 3 away from the hologram color filter 5.

By controlling the voltage applied between the transparent pixel electrode 24 and the transparent counter electrode 23 for each pixel of the liquid crystal display element 6 as described above to change the transmission state, color display is possible. .

[0015]

The hologram color filter as described above is laminated on a glass substrate. For example, in a layer configuration as shown in FIG. 7, the color filter 5 and the glass substrate 21 are bonded with an adhesive.
If static electricity is generated on the surface of the glass substrate or color filter, dust adheres or bubbles are mixed into the adhesive, and light is reflected at that portion, impairing the function as a hologram color filter. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and when a color filter is bonded to a glass substrate, it is possible to prevent dust and bubbles from being mixed and obtain a color filter having no defect. With the goal.

[0017]

According to the present invention, at least one surface of a hologram color filter formed on a substrate, at least one surface of both adhesive surfaces of the hologram color filter and the substrate, and a hologram color filter are opposed to each other. Antistatic treatment is applied to at least one of both surfaces of the placed substrate and both surfaces of the hologram color filter, thereby preventing the generation of static electricity and adhering dust when bonding the substrate to the hologram color filter. , Characterized in that bubbles are prevented from being mixed into the adhesive.

[0018]

Embodiments of the present invention will be described below. FIG. 1 is a diagram for explaining an antistatic treatment according to the present invention. FIG. 1A shows a hologram color filter 31 formed on a glass substrate 30 and a counter glass substrate 33.
Are laminated by bonding with an adhesive layer 32. FIG.
(B) shows a case where the adhesive layer 32 is not provided. The hologram color filter 31 and the opposing glass substrate 33 are adhered at four corners with adhesives 34, and the hologram surface B and the opposing glass substrate surface C are exposed. I have. Hologram color filter 3
Reference numeral 1 denotes a hologram color filter 5 described in FIG. 3 in which each elementary hologram has a spectral function and a condensing function, or a hologram color filter 1 described in FIG.
Each elementary hologram may have only a spectral function, such as 0, and the light-collecting function may be performed by a microlens array. In the case where no light-collecting function is provided, the microlens array is provided on the back side of the glass substrate 30. .

The adhesive layer 32 and the adhesive 34 are for bonding the hologram color filter 31 and the opposing glass substrate 33. When static electricity is generated on the bonding surface during bonding, dust adheres to the hologram color filter 31 and the adhesive. Bubbles are mixed in, and light is reflected at this portion, thereby impairing the function of the hologram color filter. Therefore, in the present invention, antistatic treatment is performed on at least one of the surfaces A and B on the hologram color filter side and the surfaces C and D on the counter glass substrate side, and desirably on all of these surfaces.

In the above description, the adhesion of dust between the hologram color filter 31 and the opposing glass substrate 33 has been described.
The same effect can be obtained by performing the same antistatic treatment on the surface E indicated by the broken line in FIGS. In this case, the glass substrate 3
0 and hologram color filter 31
At least one surface is subjected to an antistatic treatment.

The antistatic treatment of the surface of the hologram color filter is performed by adding fine particles of a conductive substance such as metal powder or carbon to the surface to impart conductivity, or by applying a lubricant to reduce the frictional resistance of the surface. Apply a film that has been made smaller, a film that has a hydroxyl group or a sulfone group and has a hydrophilic property to increase its hygroscopicity, a surface treatment with an antistatic agent, mainly a surfactant, or a film into which an antistatic agent is kneaded. Alternatively, a similar treatment is directly applied to the surface of the color filter to prevent charging.

The surfactant has a hydrophilic group and a lipophilic group, and the hydrophilic group is arranged outward toward the air, and the lipophilic group is arranged inside to form a continuous film. It absorbs ionic molecular water in it and lowers the electrical resistance of the surface to prevent charging.

Examples of the surfactant include: cationic surfactants: primary amines, tertiary amines, quaternary ammonium compounds, pyridine derivatives, anionic surfactants: sulfated oils, sulfated ester oils, sulfated amide oils, Olefin sulfate, fatty alcohol sulfate, alkyl sulfate, fatty acid ethyl sulfonate, alkyl sulfonate, alkylbenzene sulfonate, mixture of naphthalene sulfonate and formalin, succinate sulfonate, phosphoric acid Ester salt Nonionic activator: Partial fatty acid ester of polyhydric alcohol, ethylene oxide adduct of fatty alcohol, ethylene oxide adduct of fatty acid, ethylene oxide adduct of fatty amino or fatty acid amide, ethylene oxide addition of alkylphenol , Ethylene oxide adducts of alkyl naphthol, partial fatty acid ethylene oxide adduct amphoteric surfactant ... carboxylic acid derivatives of esters of polyhydric alcohols, imidazoline derivatives and the like are used.

In addition, there are also fatty acid amides, aliphatic amines, urea derivatives and the like, which are used alone or in combination with the above-mentioned surfactants. Further, as an inorganic compound, silicon tetrachloride is used, and when it is treated with an organic solvent such as benzol to form an inorganic polymer film, it has hygroscopicity, lowers surface resistance, and provides an antistatic effect.

Similarly, the antistatic treatment of the opposing glass substrate is performed by applying an antistatic agent such as a lubricant or a surfactant.

As described above, the hologram color filter 31
The surface of the glass substrate 33 and the surface of the opposite glass substrate 33 are subjected to an antistatic treatment to suppress generation of static electricity, thereby preventing dust from adhering when adhering with an adhesive and preventing bubbles from being mixed into the adhesive. Can be.

FIG. 2 is a diagram showing an example in which the antistatic treatment of FIG. 1 is applied to the liquid crystal display of FIG. Liquid crystal display element 6
Is the same as that shown in FIG. 7 (however, the polarizing plate is omitted), and the detailed description is omitted. The liquid crystal display element 6 and the hologram color filter 5 formed on the glass substrate 26 are bonded with the bonding layer 32. At this time, the hologram color filter 5 and the surface of the glass substrate 21 are subjected to the antistatic treatment described with reference to FIG. Therefore, generation of static electricity at the time of bonding is suppressed, adhesion of dust and mixing of bubbles are prevented, and the function of the hologram color filter is not hindered.

[0028]

As described above, according to the present invention, at least one of the surface of the hologram color filter and the surface of the opposing glass substrate is subjected to an antistatic treatment, whereby generation of static electricity is suppressed, and dust is generated during bonding. Can be prevented from adhering and bubbles can be mixed into the adhesive.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an antistatic process according to the present invention.

FIG. 2 is a diagram illustrating an example in which antistatic processing is applied to a liquid crystal display device.

FIG. 3 is a schematic sectional view of a liquid crystal display device using a hologram color filter of a first type.

FIG. 4 is a schematic sectional view of a liquid crystal display device using a second type of hologram color filter.

FIG. 5 is a schematic sectional view of a liquid crystal display device using the hologram color filter of the modification of FIG.

6 is a sectional view of a liquid crystal projection display device using the liquid crystal display device of FIG.

FIG. 7 is a sectional view of a liquid crystal display element.

[Explanation of symbols]

3 ... Backlight, 3B ... Backlight separated B
Component, 3G ... G component of the backlight, 3R ...
R component separated from backlight, 4 black matrix, 5 hologram array (hologram color filter), 5 'small hologram, 6 liquid crystal display element, 6' liquid crystal cell, 7 hologram, 8 collection Optical microlens array, 8 'microlens, 10 hologram color filter, 11 color liquid crystal display,
12, 13: polarizing plate, 14: lighting device, 15: metal halide lamp, 16: parabolic mirror, 17: field lens, 18: projection lens, 19: screen, 21: backlight-side glass substrate, 22: display surface Side glass substrate, 2
Reference numeral 3 represents a transparent counter electrode, 24 represents a transparent pixel electrode, 25 represents a liquid crystal layer, 26 represents a substrate, 30 represents a glass substrate, 31 represents a hologram color filter, 32 represents an adhesive layer, and 33 represents a counter glass substrate.

Claims (4)

[Claims] 1. An element condensing hologram array comprising: an array of element condensing holograms; each element condensing hologram transmits white light incident at a predetermined angle to a normal to a hologram recording surface substantially along the hologram recording surface; A hologram color filter that disperses and disperses wavelengths in the direction, or a hologram or diffraction grating composed of parallel and uniform interference fringes and an array of element condensing lenses, each of which is a hologram or In cooperation with the diffraction grating, a hologram color filter that disperses and disperses the wavelength of white light incident on the recording surface of the hologram or diffraction grating at a predetermined angle in a direction substantially along the surface of the array of element condensing lenses, A hologram color filter obtained by performing an antistatic treatment on at least one surface of the hologram color filter. 2. The hologram color filter according to claim 1, wherein the hologram color filter is laminated on a substrate, and an antistatic treatment is applied to at least one of both bonding surfaces of the hologram color filter and the substrate. A hologram color filter, characterized in that: 3. The hologram color filter according to claim 1, wherein a counter substrate is disposed on the hologram color filter, and at least one of both surfaces of the hologram color filter, both surfaces of the hologram color filter and the substrate, and both surfaces of the counter substrate. A hologram color filter having one surface subjected to an antistatic treatment. 4. A liquid crystal display device using a hologram color filter according to claim 3, wherein a liquid crystal display element is laminated on the opposing substrate in the hologram color filter according to claim 3.