JPH049922A - Projection type color liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a bright display and to prevent a lens array from being damaged in a production process by arranging a microlens on the liquid crystal side and laminating a microsheet on the lens array. CONSTITUTION:A projection type liquid crystal display panel consists of an active matrix base 27 and a counter base 22, the microlens array 2 consists of many microlenses 12 is arranged on the side of a liquid crystal layer 8. On the other hand, a thin plate glass 4 to be a microsheet is stuck to a lens side face with ultraviolet curing resin. Consequently, a distance between the microlens 12 and the aperture part of a black matrix 5 can be set up to a small value and light made obliquely incident upon the lens 12 can also be led into the layer 8. Since the microsheet is used, then lens array 2 of conventional thickness can be used and prevented from being damaged in the production process.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a projection type color liquid crystal display device having a microlens for focusing irradiation light onto each picture element.

(Prior Art) A projection type color liquid crystal display device is used to realize a large screen display using a lightweight and compact device. In a projection type color liquid crystal display device, light is irradiated from behind a liquid crystal panel and a color image is projected onto a screen. Projection type color liquid crystal display devices include those of a three-panel type and those of a one-panel type. In the three-panel system, red,
Three liquid crystal panels for green and blue are used, and images corresponding to each color are superimposed. In this way, the three-panel system requires a liquid crystal panel for each color, which has the disadvantage that the display device is large and relatively heavy, and the manufacturing cost is high. On the other hand, in the one-panel method, a color image is projected by providing red, green, and blue color filters on one panel. Therefore, by using a single panel system, it is possible to reduce the size, weight, and cost of the display device.

However, in order to obtain the same resolution with a single-panel system as with a three-panel system, the number of picture elements to be formed on one panel must be made three times the number of pixels on each panel used in the three-panel system. It becomes necessary. To increase the number of picture elements in this way,
Each picture element would have to be made very small. The size of the switching element provided corresponding to each picture element, the width of each bus wiring, etc. cannot be made smaller in proportion to the picture element electrode if the picture element electrode falls below a certain size.
In a single-panel display device having small picture element electrodes, the aperture ratio (the ratio of the total area of the picture element electrodes to the entire display screen) is low. If a projection type color liquid crystal display device with a low aperture ratio is used, the resulting display screen will be dark even if a light source of the same brightness is used.

In order to solve these problems, a projection type color liquid crystal display device having a microlens array has been developed (Japanese Patent Application Laid-Open No. 60-165621-4, Japanese Patent Application Laid-open No. 61-1).
1788, and JP-A-62-36636-7). An example of a liquid crystal panel of a projection type color liquid crystal display device having a microlens array is shown in FIGS. 4 and 5. The display device shown in FIG. 4 includes an active matrix substrate 27 and a counter substrate 22.
and has. The active matrix substrate 27 includes a transparent substrate 7, a pixel electrode 16, and a thin film transistor (hereinafter referred to as rTFT) 1 that functions as a switching element.
5 is formed. The counter substrate 22 has a configuration in which a counter electrode 17 is formed on a microlens array 2 having a large number of microlenses 12, and a color filter 6 corresponding to the pixel electrode 16 on the active matrix substrate 27 is further formed. There is. Although not shown in FIG. 4, a black matrix 5 is provided between the microlens array and the counter electrode 17 (FIG. 6). The microlens array 2 has a structure in which microlenses 12 are formed on a transparent substrate 32.
2 is formed on the surface of the substrate 32 opposite to the surface on which the counter electrode 17 is formed. Active matrix substrate 27
A liquid crystal layer 8 as a display medium is sandwiched between and the counter substrate 22.

The microlens array 2 shown in FIG.
It has a configuration in which a large number of microlenses 12 are formed,
The counter substrate 22 of the display device shown in FIG. 5 has a structure in which a transparent substrate 34 is pasted to a transparent substrate 33 on the opposite side of the liquid crystal panel. In this display device, the microlens 12 is formed on the surface of the substrate 34 on the substrate 33 side. The configuration of other parts is similar to that of FIG. 4.

In a projection type color liquid crystal display device provided with a microlens, as shown in FIG. 6, light incident on the microlens 12 is focused and enters the liquid crystal layer 8 without being blocked by the black matrix 5. By providing the microlens 12 in this manner, the irradiated light can be focused on the picture element electrode 16, and the display screen can be prevented from becoming dark due to a decrease in the aperture ratio.

(Problem to be Solved by the Invention) However, since the light (parallelism θ) that is incident obliquely from the direction of the optical axis of the microlens 12 is blocked by the black matrix 5 as shown in FIG. There is a problem that the light condensing effect of the microlens 12 cannot be obtained.

In order to solve this problem, the following improvement measures can be considered.

(1) Transparent substrate 32 of microlens array 2 in FIG. 4
The distance between the microlens 12 and the liquid crystal layer 8 is reduced by reducing the thickness of the microlens 12 or by reducing the thickness of the transparent substrate 33 shown in FIG.

(2) The parallelism of the incident light is improved so that the incident light enters the microlens 12 in a state close to parallel to the optical axis.

Of these two improvement measures, (2) is less practical because the light source 19 cannot be a point light source.

In the improvement measure (1), as shown in FIG. 8, incident light with parallelism θ is also guided into the liquid crystal layer by the microlens 12. However, when the thickness of the transparent substrate 32 of the microlens array 2 shown in FIG. 4 is reduced, there is a problem that the substrate 32 is damaged during the process of applying and baking the alignment film. Moreover, if the thickness of the transparent substrate 33 in FIG. 33 is damaged.

The present invention solves these problems, and an object of the present invention is to provide a projection type color liquid crystal display device that has a bright display screen and does not increase the occurrence of breakage during the manufacturing process. .

(Means for Solving the Problems) A projection type color liquid crystal display device of the present invention includes an active matrix substrate having a large number of picture element electrodes, and a microlens array having microlenses corresponding to each picture element electrode. A projection type color liquid crystal display device comprising a counter substrate and a liquid crystal layer sandwiched between the active matrix substrate and the counter substrate, the microlens being provided on the liquid crystal layer side of the microlens array. and a microsheet is provided on the microlens array, thereby achieving the above object.

Further, the microlens is provided on the liquid crystal layer side of the microlens array, the color filter is provided on the microlens array, and the microsort is provided on the entire surface of the color filter. You can also do it.

Furthermore, the microsheet may be made of either thin glass or polymer film.

(Example) Examples of the present invention will be described below.

FIG. 1 shows a schematic configuration diagram of an embodiment of a projection type color liquid crystal display device of the present invention. The projection type color liquid crystal display device of this embodiment includes a light source 19, a reflecting mirror 13, and a condenser lens 10.
, a liquid crystal panel 1, and a projection lens 11. The image obtained by this display device is projected onto the screen 14.

The light sources include halogen lamps, metalloid lamps,
A xenon lamp or the like is used. The reflecting mirror is provided to reflect the light emitted from the light source to the side opposite to the condenser lens 10 toward the condenser lens 10. Although the present embodiment shows the case of Koehler illumination, it can also be applied to other cases such as telecentric illumination.

FIG. 2 shows a cross-sectional view of the liquid crystal panel l. The liquid crystal panel 1 has an active matrix substrate 27 and a counter substrate 22. Active matrix substrate 27 and counter substrate 2
A liquid crystal layer 8 is sandwiched between 2 and 2. LCD panel 1
Although twisted nematic mode was used as the display mode, other display modes may also be used. Polarizing plates are used in many display modes. The polarizing plate can also be attached directly to the liquid crystal panel 1. However, when using a high-intensity light source, it is preferable not to attach the polarizing plate directly to the liquid crystal layer 8 because the temperature increase due to light absorption by the polarizing plate will adversely affect the operating characteristics of the liquid crystal layer 8. The polarizing plate may be installed at any position as long as nothing that changes the polarization characteristics of light is inserted between the polarizing plate and the liquid crystal panel 1.

As shown in FIG. 2, in the active matrix substrate 27, a picture element electrode 16 is provided on the transparent substrate 7, and a transistor connected to the picture element electrode 16 functions as a switching element.
FT15 is formed.

An alignment film 18 is formed on the entire surface of this substrate 7, covering the picture element electrodes 16 and TFTs 15.

The microlens array 2 constituting the counter substrate 22 has a configuration in which a large number of microlenses 12 are formed on a transparent substrate 32. The following method has been proposed as a method for forming the microlens array 2.

■A method of molding plastic or glass using a mold.

■A method of forming a convex lens by exposing a photosensitive resin film in a certain pattern and utilizing the phenomenon that unreacted monomer moves from the unexposed area to the exposed area, causing the exposed area to bulge.

■A thermoplastic resin film is patterned into the shape of the lens in plan view using a known photolithography method, and then heated to a temperature above the softening point of the resin to cause sagging at the edges of the pattern. method to form a convex lens.

(2) A method of forming a convex lens by subjecting a photosensitive resin film to proximity exposure and creating a distribution in the amount of photoreactants depending on the blurring of the edges of the exposed pattern.

■A method of creating a lens effect by irradiating a photosensitive resin film with light with an intensity distribution and forming a refractive index distribution that corresponds to the intensity of the light.

■A method to obtain a gradient index lens by selective ion diffusion.

■A method of forming convex lenses by irradiating photosensitive glass with light and utilizing the shrinkage caused by crystallization.

In this example, a microlens array 2 formed by the selective ion diffusion method (2) among the above methods was used.

On the surface of the microlens array 2 on which the microlenses 12 are formed, a thin plate glass 4, which is a microsheet, is attached using an ultraviolet curing resin 3. The thickness of the thin glass sheet 4 is preferably in the range of 0.1 to 0.5. In this example, 0.2 mm thin glass was used.

As the ultraviolet curing resin 3, one manufactured by Nippon Loctite was used.

The microlens array 2 and the thin glass 4 are bonded together by dropping ultraviolet curing resin 3 onto the microlens array 2.
Place the thin glass 4 on top of it to prevent air bubbles from entering,
This was done by irradiating with ultraviolet light.

A black matrix 5 is formed on the thin glass 4. The black matrix 5 was formed by patterning a film of black resist (manufactured by Fuji Hunt Electronics). For the black matrix 5, an interference color filter containing an inorganic material, a metal film, etc. can also be used. A color filter 6 having a larger area than the opening is patterned in the opening of the black matrix 5. The color filter 6 was formed by buttering films of red resist, green resist, and blue resist (all manufactured by Fuji Hunt Electronics).

An interference color filter containing the above-mentioned inorganic material can also be used as the color filter 6. Furthermore, the entire surface of the black matrix 5 and color filter 6 is coated with ITO.
A counter electrode 17 is formed. Counter electrode 17
An alignment film 18 is formed thereon.

In the projection type color liquid crystal display device of this embodiment, a microlens 12 is provided on the surface of the microlens array 2 on the liquid crystal layer 8 side, and a thin glass plate 4 is provided on the microlens array 2.
, the distance between the microlens 12 and the liquid crystal layer 8 within the opening of the black matrix 5 can be set small. Due to this i-formation, much of the light incident on the microlens 12 at an angle from the direction of the optical axis of the microlens element 2 can be guided to the liquid crystal layer 8 within the opening of the black matrix 5. Further, since the microlens array 2 can have the same thickness as the conventional one, the occurrence of damage to the microlens array 2 during the manufacturing process does not increase.

FIG. 3 shows another embodiment of the liquid crystal panel used in the projection type color liquid crystal display device of the present invention. The structure of the active matrix substrate 27 of the liquid crystal panel 1 of this embodiment is the same as that of the embodiment shown in FIG. 2 described above. On the counter substrate 22, a microlens array 2 similar to the embodiment shown in FIG.
Red, green, and blue color filters 6 are formed corresponding to each microlens 12. A thin plate glass 4 serving as a micronotebook is pasted onto these color filters using an ultraviolet curing resin 3. The thickness of the thin glass top 4 is 0. It is 2mm.

A black matrix 5 having openings corresponding to each color filter 6 is formed on the thin glass 4, and furthermore, an IT
A counter electrode 17 made of O is formed. Counter electrode 1
An alignment film 18 is formed on the substrate 7 .

Also in the projection type color liquid crystal display device of this embodiment, the microlens 12 and the liquid crystal layer 8 within the opening of the black matrix 5
Since the distance between the microlens 12 and the microlens 12 is set small, most of the light incident on the microlens 12 at an angle from the direction of the optical axis of the microlens 12 can be guided to the liquid crystal layer 8 within the opening of the black matrix 5. Furthermore, the occurrence of damage to the microlens array 2 during the manufacturing process does not increase.

Next, still another embodiment of the liquid crystal panel of the projection type color liquid crystal display device of the present invention will be described. The structure of this embodiment is similar to that of the embodiment shown in FIG. 2, except that a polymer film is used as the micro/tooth. When a polymer film exhibiting optical anisotropy, such as a polyester film, is used, a problem arises in that the film appears rainbow-colored due to the two polarizing plates. Therefore,
It is necessary to select and use a polymer film that does not exhibit optical anisotropy. In this example, a polycarbonate film with a thickness of 0.2 mm was used.

Also in the projection type color liquid crystal display device of this embodiment, the microlenses 1 are tilted from the direction of the optical axis of the microlens array 2.
2 can be guided to the liquid crystal layer 8 within the opening of the black matrix 5. Furthermore, the occurrence of damage to the microlens array 2 during the manufacturing process does not increase.

(Effects of the Invention) In the projection type color liquid crystal display device of the present invention, the microlens is provided on the liquid crystal layer side of the microlens array, and the micronote is provided on the microlens array. The distance to the microlens layer can be set small. With this configuration, most of the light incident on the microlens at an angle from the direction of the optical axis of the microlens can be guided to the liquid crystal layer. Since the thickness can be freely set, the occurrence of damage to the microlens array during the manufacturing process is also reduced.
There is no reduction in manufacturing yield.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of a projection type color liquid crystal display device of the present invention, FIG. 2 is a sectional view of a liquid crystal panel constituting the display device of FIG. 1, and FIG. 4 and 5 are cross-sectional views of a conventional liquid crystal panel used in a conventional projection-type color liquid crystal display device, and FIGS. 6 to 8 are cross-sectional views of the example, and FIGS. FIG. 1...Liquid crystal panel, 2...Microlens array,
3... Ultraviolet curing resin, 4... Thin glass, 5...
・Black matrix, 6... Color filter, 7,
32... Transparent substrate, 8... Liquid crystal layer, 10... Condenser lens, 11... Projection lens, 12... Micro lens, 13... Reflector, 14... Screen, 15... ...T P T. 16... Picture element electrode, 17... Counter electrode, 18...
Alignment film, 19... Light source, 22... Counter substrate, 27.
・Actitu matrix board. that's all

Claims (1)

[Claims] 1. An active matrix substrate provided with a large number of picture element electrodes, a counter substrate provided with a microlens array having microlenses corresponding to each picture element electrode, and the active matrix substrate and the counter substrate. a projection type color liquid crystal display device comprising: a liquid crystal layer sandwiched between the microlens array and the liquid crystal layer, the microlens being provided on the liquid crystal layer side of the microlens array; Projection type color liquid crystal display device. 2. An active matrix substrate equipped with a large number of picture element electrodes, a counter substrate equipped with a microlens array having microlenses corresponding to each picture element electrode, and a color filter corresponding to each microlens, and the active matrix substrate. and a liquid crystal layer sandwiched between the counter substrate, the microlens being provided on the liquid crystal layer side of the microlens array, and the color crystal layer being disposed on the microlens array. A projection type color liquid crystal display device provided with a filter and a microsheet provided on the entire surface of the color filter. 3. The projection type color liquid crystal display device according to claim 1 or 2, wherein the microsheet is either a thin plate glass or a polymer film.