JP3389742B2 - Method of manufacturing interference filter and liquid crystal device using interference filter - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an interference filter and a liquid crystal device using the interference filter.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 3-140903 discloses a method of manufacturing an interference filter using an optical fiber. In the manufacturing method, light having the three primary colors of light, that is, half the wavelengths of R, G, and B, is incident on the optical fiber bundle.
The opposite end of the optical fiber bundle is arranged on the photosensitive material (optical fiber) in accordance with the arrangement of the light modulation filters in the liquid crystal panel. A metal film such as aluminum is deposited on the back surface of the substrate on which the photosensitive material is formed. The color light emitted from the optical fiber bundle enters the photosensitive material, and the light transmitted through the photosensitive material is reflected by the metal film. As a result, two lights interfere with each other in the photosensitive material and a periodic light intensity distribution is formed in the photosensitive material. Thus, the refractive index of the photosensitive material is periodically modulated, and this refractive index distribution functions as an interference filter. The metal film deposited on the back surface of the photosensitive material is removed with an acid after the interference filter is formed.

[0003]

With the rapid increase in demand for liquid crystal display devices in recent years, higher definition of display images is increasing as a market demand. As a result, the number of pixels of the liquid crystal display panel is increasing, and accordingly, the required pixel size is decreasing. For example, in the case of a high-definition television-compatible liquid crystal panel, the number of pixels is up to 1000 × 1000 and the pixel size is 50 × 50 μm or less. Each pixel has an optical modulation filter such as an interference filter. Further, there are various arrangements of the respective color elements of the light modulation filter. Considering the actual situation as described above, it is extremely difficult to accurately arrange a large number of optical fibers in accordance with the arrangement of the interference filters of the liquid crystal panel. Therefore, it is technically difficult to mass-produce the interference filter by the above-described method of manufacturing the interference filter using the optical fiber.

However, considering the characteristics of the interference filter as a light modulation filter, the market needs for liquid crystal display devices using the interference filter are very high. Therefore, a technique for mass-producing interference filters with high accuracy and easily has long been desired in the market.

[0005]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems of the prior art, and provides a method of manufacturing an interference filter by a simple means and a liquid crystal device using the interference filter. To do.

The method of manufacturing an interference filter of the present invention has the following features.

A light beam containing a plurality of color components is transmitted through a mask having a pattern formed of a plurality of color elements, and the light beam split into the plurality of color components by passing through the mask is afocal optical. After passing through the system, one surface of the base material made of a photosensitive material is irradiated, and a light beam having a specific phase relationship with the light beam irradiated to the one surface of the base material is applied to the other surface of the base material. The surface of the substrate, the light beam irradiated on the one surface of the substrate, and the light beam irradiated on the other surface of the substrate are caused to interfere with each other to change the refractive index of the substrate, and the pattern It is characterized by forming a color pattern corresponding to.

Further, a reflecting plate is disposed on the other surface side of the base material, and a light beam applied to one surface of the base material is transmitted through the base material and then reflected by the reflecting plate. The light reflected by the reflection plate irradiates the other surface of the base material.

Further, a light ray composed of a plurality of color components is separated into a first light ray and a second light ray by an amplitude separating means, and the first mask is formed on the mask in which a pattern composed of a plurality of color elements is formed. After passing a light beam and passing the first light beam, which has been demultiplexed into the plurality of color components by passing through the mask, through the afocal optical system, one surface of the base material made of a photosensitive material is And irradiating the other surface of the base material with the second light ray, and changing the refractive index of the base material by causing the first light ray of the base material and the second light ray to interfere with each other. Then, a color pattern corresponding to the pattern is formed.

Further, one surface of the interference filter manufactured by the manufacturing method according to any one of claims 1 to 3 and one surface of the base material made of a photosensitive material are arranged so as to face each other. , Irradiating a ray containing a plurality of color components from the other surface side of the base material, the light ray passing through the base material,
The same color pattern as the color pattern of the interference filter is changed by changing the refractive index of the base material by causing the light ray reflected by the interference filter and passing through the base material and the light ray reflected by the interference filter to interfere with each other. Is formed.

The liquid crystal device of the present invention has the following features.

An interference filter obtained by the manufacturing method according to any one of claims 1 to 4, wherein a first transparent substrate having a first transparent electrode on one surface and a second transparent electrode on the other surface. And a second substrate arranged in such a manner that the first transparent electrode and the interference filter face each other, and a second substrate arranged between the first substrate and the second substrate. And a liquid crystal layer that is formed.

[0013]

[0014]

According to the first aspect of the present invention, a light beam containing a plurality of color components is transmitted through a mask on which a pattern composed of a plurality of color elements is formed, and the light beams containing the plurality of color components are transmitted to the plurality of color components. After passing the demultiplexed light beam through the afocal optical system, it is irradiated on one surface of the base material made of a photosensitive material, and a specific phase relationship with the light beam irradiated on the one surface of the base material is established. A light ray having is applied to the other surface of the base material, and a light ray applied to the one surface of the base material,
The refractive index of the base material is changed by interfering with the light beam applied to the other surface of the base material, and a color pattern corresponding to the pattern is formed. Therefore, the interference filter having the same arrangement as the pattern formed on the mask can be easily manufactured with high accuracy. The plurality of color elements formed on the mask in this embodiment are preferably RGB,
The light beam is preferably a white laser beam containing RGB color components or a beam composed of a plurality of laser beams. These points are the same in the following.

Further, in claim 2 of the present invention, a reflecting plate is arranged on the other surface side of the base material, and a light beam irradiated on one surface of the base material passes through the base material. rear,
The light reflected by the reflector and reflected by the reflector illuminates the other surface of the base material. For this reason,
Since it is not necessary to separately make a light beam for irradiating from one surface of the substrate and a light beam for irradiating from the other surface of the substrate,
It is possible to cause light interference very efficiently. Furthermore, the incident angle of light from the other surface can be easily adjusted. By changing the incident angle of the two light fluxes to be interfered with each other, the fringes of the refractive index distribution can be tilted, so that an interference filter capable of reflecting obliquely incident light in the front direction is realized. According to a third aspect of the present invention, a light beam composed of a plurality of color components is separated into a first light beam and a second light beam by an amplitude separation means, and a mask formed with a pattern composed of a plurality of color elements is formed. After passing the first light beam and the first light beam, which has been split into the plurality of color components by passing through the mask, through the afocal optical system, a substrate made of a photosensitive material is formed. Irradiating one surface, irradiating the second light ray to the other surface of the base material, and causing the first light ray of the base material and the second light ray to interfere with each other. Change the refractive index,
A color pattern corresponding to the pattern is formed. Therefore, as in the case of the second embodiment, the first light ray and the second light ray can be generated from the same light source, so that light interference can be very efficiently performed.

According to a fourth aspect of the present invention, one surface of the interference filter obtained by the manufacturing method according to any one of the first to third aspects and one surface of the base material made of a photosensitive material are provided. Are arranged so as to face each other, a light ray containing a plurality of color components is irradiated from the other surface side of the base material, the light ray passing through the base material is reflected by the interference filter, and the base material is The light ray that has passed through and the light ray that has been reflected by the interference filter are interfered with each other to change the refractive index of the base material and form the same color pattern as the color pattern of the interference filter. Therefore, it is possible to mass-produce the high-precision interference filter with a very simple device based on one high-precision interference filter.

According to the present invention, the first transparent substrate having the first transparent electrode on one surface and the second transparent electrode on the other surface are provided by the manufacturing method according to any one of claims 1 to 4. A second substrate in which the obtained interference filters are sequentially arranged, and the first transparent electrode and the interference filter are arranged to face each other; the first substrate; and the second substrate. A liquid crystal device having a liquid crystal layer disposed between the two. This realizes a bright and high-definition pixel liquid crystal display element.

[0018]

[0019]

【Example】

(Embodiment 1) FIG. 1 shows the structure of an optical system for producing an interference filter. A beam emitted from a white laser light source having three primary colors of RGB is converted into expanded parallel light 101 and applied to a mask 102. A color filter is formed on the mask 102. RG in the color filter
A part of the sequence of B is shown in FIG. This arrangement is equal to the arrangement that is widely adopted for color liquid crystal panels. The color filter on the mask has a transmission wavelength range only in the vicinity of the main wavelengths of RGB, and demultiplexes the RGB light obtained from the white laser light source. This color filter can be manufactured by a manufacturing method of a color filter used in a conventional liquid crystal panel, for example, a printing method.

An image of the mask 102 is formed on the photosensitive material 105 using an afocal optical system composed of the lens 103 and the lens 104. A light reflective member 106 is arranged behind the substrate on which the photosensitive material 105 is formed. The light transmitted through the photosensitive material 105 is reflected by the light reflecting member 106 to obtain reflected light. The light incident on the photosensitive material 105 and the reflected light interfere with each other to form a periodic intensity distribution in the photosensitive material 105. A refractive index matching agent is filled between the substrate of the photosensitive material 105 and the light reflecting member 106 to prevent reflected stray light.

After the interference exposure, a periodical refractive index distribution can be formed in the photosensitive material 105 by subjecting the photosensitive material 105 to an appropriate treatment, if necessary. This refractive index distribution functions as an interference filter and reflects only light in a specific wavelength range. The fringes of the refractive index distribution formed on the photosensitive material 105 are substantially parallel to the surface of the photosensitive material. The cycle of stripes differs for each colored light.

The reflection spectra of the produced interference filter are shown in FIGS. 5 (a), 5 (b) and 5 (c). An interference filter for color light B, an interference filter for color light G, and an interference filter for color light R, respectively. The width of the reflection wavelength region can be controlled by changing the modulation depth of the refractive index. Generally, the width of the reflection wavelength band is narrowed by increasing the thickness of the photosensitive material to reduce the refractive index modulation degree (Bell. Syst.
See Tech. J. 48, 2909 (1969)). In this example, a hologram recording photopolymer was used as the photosensitive material. In this example, the thickness of the photopolymer layer is approximately
The photopolymer layer has a refractive index modulation degree Δn of about 0.010 to 0.10. An example of this type of photopolymer is the holographic photopolymer of DuPont (see Proc. SPIE 1212, 30 (1990)).

By the manufacturing method of the present invention, it is possible to easily and accurately manufacture an interference filter array having an arbitrary array. Although a white laser is used as a light source in the embodiment, beams from a plurality of lasers having different wavelengths may be combined and used instead.

(Embodiment 2) FIG. 3 shows the structure of an optical system for producing an interference filter. Expands the beam emitted from the color laser light source having the three primary colors of RGB, parallel light 1
The value is set to 01 and the beam splitter 301 performs amplitude division. One beam 302 is applied to the mask 102. The mask is the same as that used in Example 1, the color filter on the mask has a transmission wavelength range only in the vicinity of the main wavelengths of RGB, and demultiplexes the RGB light obtained from the white laser light source.

An image of the mask 102 is formed on the photosensitive material 105 by using an afocal optical system composed of the lens 103 and the lens 104. The other split beam 3
03 is applied to the photosensitive material from the side facing the beam 302. A periodic light intensity distribution is formed in the photosensitive material by the interference of the two beams.

After the interference exposure, a periodical refractive index distribution can be formed in the photosensitive material 105 by subjecting the photosensitive material 105 to an appropriate treatment, if necessary. This refractive index distribution functions as an interference filter and reflects only light in a specific wavelength range. The fringes of the refractive index distribution formed on the photosensitive material 105 are substantially parallel to the surface of the photosensitive material in the arrangement of FIG. The cycle of stripes differs for each colored light. The reflection spectrum of the manufactured interference filter is similar to that shown in FIG.

It should be noted that the angle between the two light beams to be interfered (see FIG.
In the case of, the fringes of the refractive index distribution can be easily tilted by changing (180 degrees). By doing so, it becomes possible to shift the reflection direction of the light from the interference filter from the direction determined by the regular reflection condition. This effect will be described in Example 4.

By the manufacturing method of the present invention, it is possible to easily and accurately manufacture an interference filter array having an arbitrary array. Although a white laser is used as a light source in the embodiment, beams from a plurality of lasers having different wavelengths may be combined and used instead.

(Embodiment 3) FIG. 4 shows a structure for producing an interference filter. A beam emitted from a color laser light source having the three primary colors of RGB is converted into expanded parallel light 401 and applied to a photosensitive material to be subjected to interference exposure. 4 in the figure
Reference numeral 02 is a glass substrate, and 403 is a photosensitive material.

An interference filter (referred to as a master filter) manufactured by the method of Embodiment 1 or 2 is arranged below or under the photosensitive material so as to be close to or in contact therewith. 40 in the figure
4 is a photosensitive material on which an interference filter is formed, 405
Is a glass substrate. A beam illuminating the photosensitive material to be subjected to interference exposure from above is interfered with a beam reflected from the master filter to form a periodic light intensity distribution in the photosensitive material.

After the interference exposure, a periodical refractive index distribution can be formed in the photosensitive material 403 by subjecting the photosensitive material 403 to an appropriate treatment, if necessary. This refractive index distribution functions as an interference filter and reflects only light in a specific wavelength range. The refractive index distribution formed in the photosensitive material 403 is the same as the refractive index distribution in the master filter, so that the reflection spectrum is also the same.

By the manufacturing method of the present invention, it is possible to easily and accurately manufacture an interference filter array having an arbitrary array. Although a white laser is used as a light source in the embodiment, beams from a plurality of lasers having different wavelengths may be combined and used instead.

(Embodiment 4) A liquid crystal panel of the present invention is a reflection type liquid crystal panel having an interference filter manufactured by the manufacturing method described in Embodiments 1 to 3. FIG. 6 shows a sectional view of the liquid crystal panel. When viewed from the viewer 601 side, the interference filter is arranged behind the liquid crystal layer of the liquid crystal panel. In the figure, 602 is a transparent substrate, 603 is a transparent electrode, 604 is a liquid crystal layer, 605 is an interference filter, 606 is a transparent electrode, and 607 is a transparent substrate.

The illumination light 608 is white light from a general room light. Of course, it may be sunlight. Transparent substrate 602
Light incident on the liquid crystal layer 604 passes through the interference filter 605.
To For example, focusing on the interference filter of the colored light G,
G light of the illumination light is reflected, and R and B lights pass through the interference filter. The reflected G light is intensity-modulated while passing through the liquid crystal layer, goes out of the liquid crystal panel, and appears to the viewer 6
01. On the other hand, the R and B lights that have passed through the interference filter 605 are processed so as not to reach the viewer after passing through the transparent substrate 607 as they are. Similar wavelength selection functions can be obtained for the interference filter for the color light R and the interference filter for the color light B.

As described in the second embodiment, the obliquely incident light (608 in FIG. 6) can be reflected in the front direction by inclining the fringes in the interference filter with respect to the surface thereof. By doing so, the information (pictures, characters, etc.) displayed on the liquid crystal panel can be efficiently transmitted to the viewer.

By using the interference filter array manufactured by the manufacturing method of the present invention, bright and excellent color reproducibility can be realized.

In this embodiment, the reflection type liquid crystal display device has been described, but it goes without saying that the interference filter of the present invention can be used in a transmission type liquid crystal display device.

[0038]

According to the method of manufacturing an interference filter of the present invention, an interference filter having an arbitrary array can be manufactured easily and accurately. Further, by using the interference filter in the liquid crystal panel, it is possible to realize a bright liquid crystal device having excellent color reproducibility.

[0039]

[Brief description of drawings]

FIG. 1 is a diagram showing a first color filter manufacturing method of the present invention.

FIG. 2 is a plan view showing an arrangement of color filters on a mask.

FIG. 3 is a diagram showing a second color filter manufacturing method of the present invention.

FIG. 4 is a diagram showing a third color filter manufacturing method of the present invention.

FIG. 5 is a diagram showing a reflection spectrum of the color filter of the present invention. (A) Reflection spectrum of interference filter for color light B (b) Reflection spectrum of interference filter for color light G (c) Reflection spectrum of interference filter for color light R

FIG. 6 is a cross-sectional view of a liquid crystal display panel equipped with the interference filter of the present invention.

[Explanation of symbols]

101 beam 102 Mask with color filter 103 lens 104 lens 105 Photosensitive material 106 reflective member 107 reflected light 201 mask 301 beam splitter 302 beam 303 beam 401 beam 402 glass substrate 403 Photosensitive material 404 Photosensitive material (interference filter formed) 405 glass substrate 601 viewer 602 transparent substrate 603 transparent electrode 604 Liquid crystal layer 605 Interference filter 606 transparent electrode 607 transparent substrate 608 illumination light

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-244004 (JP, A) JP-A-3-113402 (JP, A) JP-A-3-198004 (JP, A) JP-A-6- 313812 (JP, A) JP-A-2-244086 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 5/32 G02B 5/18 G02B 5/20

Claims (4)

(57) [Claims] 1. A light beam containing a plurality of color components is transmitted through a mask having a pattern formed of a plurality of color elements, and the light beam containing the plurality of color components is transmitted through the mask to be divided into the plurality of color components.
After the wave rays passed through the afocal optical system, is irradiated on one surface of a substrate made of a photosensitive material, having a specific phase relationship with the beam applied to said one surface of said substrate A light ray is applied to the other surface of the base material, and a light ray applied to the one surface of the base material and a light ray applied to the other surface of the base material are caused to interfere with each other. A method of manufacturing an interference filter, which comprises changing a refractive index to form a color pattern corresponding to the pattern. 2. A reflection plate is disposed on the other surface side of the base material, and a light beam applied to one surface of the base material is transmitted through the base material and then reflected by the reflection plate. The method of manufacturing an interference filter according to claim 1, wherein the light reflected by the reflection plate irradiates the other surface of the base material. 3. A first light ray and a second light ray which are composed of a plurality of color components are separated by an amplitude separating means, and the first mask is formed on the mask in which a pattern composed of a plurality of color elements is formed. A light ray is transmitted, and by being transmitted through the mask, it is divided into the plurality of color components.
The waved first light beam is passed through an afocal optical system, and then is irradiated on one surface of a substrate made of a photosensitive material, and the second light beam is irradiated on the other surface of the substrate. An interference filter characterized by changing the refractive index of the base material by causing the first light ray of the base material and the second light ray to interfere with each other to form a color pattern corresponding to the pattern. Manufacturing method. 4. The manufacturing method according to claim 1.
One surface of the interference filter manufactured by the manufacturing method and one surface of the base material made of a photosensitive material are arranged so as to face each other, a light ray containing a plurality of color components from the other surface side of the base material. And the light ray passing through the base material is reflected by the interference filter, and the light ray passing through the base material and the light ray reflected by the interference filter are caused to interfere with each other to thereby obtain a refractive index of the base material. Is formed to form the same color pattern as the color pattern of the interference filter.