JP2677435B2 - Color image display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention uses, for example, a transmissive color liquid crystal display device, and a color image display realized as a device for projecting the color image on a screen by light from a light source. Regarding the device.

<Prior Art> In order to realize a relatively large screen with a small and lightweight device, a transmissive liquid crystal display element is used, and light is emitted from a light source on the rear side to project a color image on the screen. Projection type color image display device (hereinafter abbreviated as image display device)
Is used. As the configuration of the liquid crystal display element used, red, green, and blue color signals in the image signal,
A configuration is employed in which three liquid crystal display elements that form images of these colors are used and the transmitted light from these is superimposed on the screen. However, in such a configuration, there are limitations on downsizing and weight reduction because three liquid crystal display elements are required and an optical system for aligning light of each color on the screen is separately required. It also adds to the cost.

As a second conventional example for solving such a problem, a technique of using a matrix-driven liquid crystal display device and forming a color filter for obtaining red, green, and blue transmitted light for each picture element is adopted. However, such a conventional example, in particular, a switching element such as a thin film transistor or an MIM (metal-insulator-metal) element, an individual display electrode connected to the switching element, and a drive signal line for supplying a drive signal to the display electrode Alternatively, in the case of an active matrix drive type liquid crystal display device using a scanning signal line or the like for supplying a control signal for scanning the switching element, a display electrode in a unit area and various signal lines not covered by the display, The ratio of the area occupied by the switching element and the like (hereinafter referred to as the aperture ratio) is reduced as compared with the case of other configurations. When a color image is displayed, it is necessary to downsize the display electrode and increase the pixel density. Therefore, the area of the light-shielding region that is not kept in the display is relatively increased, and the aperture ratio is increased. Is further reduced.

Due to such a reduction in the aperture ratio, there is a problem that the amount of light transmitted through the liquid crystal display device is reduced and the displayed image becomes dark.

As a third conventional example for solving the problem in the second conventional example, a technique of forming a microlens array corresponding to each picture element on the light source side of a single liquid crystal display device is adopted. The microlens array collects incident light on the display electrodes to prevent the above-mentioned decrease in the amount of transmitted light.

The following method has been proposed as a method for forming the microlens array.

A method of molding synthetic resin material or glass with a mold.

When a specific type of photosensitive resin is exposed in a pattern corresponding to, for example, a microlens array, the unreacted monomer of the photosensitive resin moves from the exposed portion to the exposed portion,
A method of forming a convex lens by utilizing the phenomenon that the exposed area rises.

Thermoplastic resin by well-known photography technology,
A method of forming a convex lens by patterning into a flat plate shape corresponding to a microlens array, and then heating to a temperature equal to or higher than the softening point to impart fluidity and causing edge sag.

A method of forming a convex lens by subjecting a photosensitive resin to proximity exposure to give a distribution to the amount of the photoreactant according to the blur of the transferred image on the photosensitive resin at the edge of the mask used for the exposure.

A method in which a photosensitive resin is irradiated with light having an intensity distribution to form a refractive index distribution according to the intensity of the light to obtain a configuration equivalent to a lens.

A method of obtaining a structure equivalent to a lens by forming a distribution of refractive index by a selective ion diffusion method with respect to a transparent substrate such as glass.

A method of forming a convex lens by utilizing the shrinkage caused by crystallization caused by light irradiation on the photosensitive glass.

Further, a method has been proposed in which the microlens array is selectively colored with a pigment or a dye as in the case of the color filter, thereby performing color display.

<Problems to be Solved by the Invention> In the third conventional example, the following problems occur because the microlens array is dyed to realize the function of the color filter. Even if you try to control the spectral characteristics that are the function of the color filter by its shape,
Since this color filter is also a microlens, it is difficult to change the shape determined based on the required lens characteristics. In addition, when it is configured as a microlens, the selection range of materials is relatively small in terms of refractive index, molecular structure, melting point, etc., and the material of the lens is limited, so the range of pigments and dyes used is also limited. There is a problem that restrictions are greatly imposed.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above technical problems, to provide a color image display device which has a compact and lightweight structure and which can significantly improve the brightness of a displayed image.

<Means for Solving the Problems> In the present invention, a light source and display picture elements that selectively transmit light from the light source are arranged in a matrix, and a light-shielding area is formed around each display picture element. And a translucent substrate provided on the light source side of the display means and having a plurality of microlenses embedded therein, wherein each microlens is provided on one side in the thickness direction of the translucent substrate. And a translucent substrate such that a color selection member for selecting the transmitted light into a predetermined color is formed at a position corresponding to the translucent substrate. A color image display device characterized in that light which is exposed to the element and is filled with a translucent material between the elements and which should enter the display element and the light-shielding region from the light source is condensed only on the display pixel by the microlens. Is.

<Operation> According to the present invention, the light from the light source is transmitted through either one of the translucent substrate formed by embedding a plurality of microlenses or the color selection member to the other, and the pixel is Light of a predetermined color is selected for each, and these lights are condensed by the microlens for each picture element of the display unit. In the display means, a light-shielding area which is a non-transmissive area is formed around each display picture element, and the light that should enter the display picture element and the light-shielding area from the light source by the function of the microlens is the display picture element. Only focused on. Therefore, as described above, the sizes of the microlens and the color selection member are formed to be larger than the size of the display picture element. Therefore, a bright color image can be obtained. A color image is displayed by the light selectively transmitted through the display unit for each picture element.

<Embodiment> FIG. 1 is a sectional view showing the configuration of a color image display device 1 according to an embodiment of the present invention. The image display device 1 is a white light source 2.
Light source light from the white light source 2 and the reflecting mirror 3 is incident on the display means 6 via, for example, a pair of condenser lenses 4 and 5. The display means 6 is constructed by stacking a color selection member 9 and a liquid crystal display element 10 in this order from the light source 2 side. The light from the display means 6 is projected on the screen 8 by the projection lens 7 to form a color image.

FIG. 2 is a sectional view showing the structure of the display means 6.
FIG. 3 shows a picture element electrode 13 as a display picture element of the liquid crystal display element 10.
It is an enlarged plan view of the vicinity. The color selection member 9 is arranged on the light source 2 side of the liquid crystal display element 10. This liquid crystal display element 10 is
For example, it is an active matrix drive type, and as shown in FIG. 3, for example, ITO (indium tin oxide) is used.
The pixel electrode 13 made of a transparent conductive material such as
The drive signals are arranged in a matrix on the display electrodes 13, and drive signals to the display electrodes 13 are supplied from drive signal lines 14 via switching elements 15 such as thin film transistors (TFT). The switching element 15 is turned on / off by inputting the scanning signal from the scanning signal line 16, and turns on / off the driving signal.

Referring again to FIG. 2, the structure of the picture element electrode 13 and the like is provided on the glass substrate 19 on the light source 2 side of the liquid crystal display element 10, and the opposite glass substrate 20 faces the picture element electrode 13 and is formed of ITO or the like. A counter electrode 21 made of a transparent conductive material is formed over the entire surface of the glass substrate 20.

In such a liquid crystal display element 10, the pixel electrode 13
Constitutes a transmissive region 17, and the drive signal line 14, the scanning signal line 16, the switching element 15 and the like constitute a light shielding region 18 which does not transmit light.

FIG. 4 is a sectional view for explaining the manufacturing process of the display means 6, and FIG. 5 is a plan view for explaining the manufacturing process. In the glass substrate 11 of FIGS. 4 (1) and 5 (1) arranged on the light source 2 side of the liquid crystal display element 10, the ions have an intensity distribution by the well-known selective ion diffusion method, and the glass substrate 11 A region having a refractive index larger than that of the glass substrate 11 is formed in a convex lens shape in the glass substrate 11, and the microlens 22 individually corresponding to the pixel electrode 13 of the liquid crystal display element 10 is As shown in FIG. 4 (2) and FIG. 5 (2), a microlens array arranged in a matrix is formed.

Color filters 23R, 23G, and 23B that are color selection members for each microlens 22 on the liquid crystal display element 10 side of the glass substrate 11 and select transmitted light as red, green, and blue, respectively.
(Collectively designated by reference numeral 23 when necessary) are formed as shown in FIGS. 4 (3) and 5 (3), respectively. The microlens 22 is a liquid crystal display device in which light incident from the light source 2 through the condenser lenses 4 and 5 is passed through each color filter 23.
Its shape is chosen so that it is incident into the 10 pixel electrodes 13. That is, if the microlens 22 is not provided, not only the light that should enter the pixel electrode 13 from the light source 2 but also the light that should enter the light-shielding region 18 will not be reflected by the microlens 22.
Is collected. To form the color filter 23,
Red, green, a synthetic resin material in which blue pigments are dispersed may be formed in a predetermined pattern for each color, and an inorganic oxide film having a different optical refractive index on the liquid crystal display element 10 side of the glass substrate 11 by sputtering. Selectively stack multiple layers,
Light from the light source 2 is red, green,
Each interference color of blue may be realized.

A glass substrate on which the color filter 23 is formed in this way
11 is a microlens with a translucent adhesive 24
Therefore, the color filters 23 and the pixel electrodes 13 are aligned with each other and fixed to the glass substrate 19. In this way, the display means 6 is integrally configured.

At this time, the light that enters the display means 6 from the light source 2 via the condenser lenses 4 and 5 is condensed by the microlens 22 on each of the picture element electrodes 13 of the liquid crystal display element 10,
When passing through the liquid crystal layer, it undergoes intensity modulation corresponding to the drive signal. After this light passes through the liquid crystal display element 10, the numerical aperture (NA) determined with respect to the microlens 22.
The aperture D1 of the projection lens 7 is selected so that it can be diffused into the cone corresponding to the solid angle determined by the above, but can receive such a light flux from any of the microlenses 22.
This makes it possible to prevent the light passing through the liquid crystal display element 10, that is, the display image, from being limited by the projection lens 7.

In this way, the light from the light source 2 passes only through the transmissive region 17 of the liquid crystal display element 10, so that the brightness of the image formed on the screen 8 is increased without unnecessarily increasing the illuminance of the light source 2. can do. Further, it is possible to reduce the size and weight of the configuration as compared with the configuration using three liquid crystal display devices corresponding to red, blue and green described in the conventional example.

The light source 2 is a white light source, and a halogen lamp, a metal halide lamp, a xenon lamp or the like is used.

<Effects of the Invention> According to the present invention as described above, the light from the light source is emitted from either one of the light-transmissive substrate formed by embedding a plurality of microlenses or the color selection member, and the other one. Light of a color that is transmitted and predetermined for each display picture element is selected, and these lights are condensed by the microlens for each display picture element of the display means. A color image is displayed by the light selectively transmitted through the display means for each display picture element. This eliminates the need for a configuration in which the display means and the light source are individually used for each color, and the size and weight of the configuration can be reduced. A light-shielding area is formed around each of the display picture elements arranged in a matrix in the display means, and light to be incident on the display picture element and the light-shielding area from the light source by the function of the microlens is transmitted to the display picture element. Therefore, the size of each microlens and the color selection member is formed larger than the size of the display pixel in the present invention.

Therefore, it is possible to prevent the situation where the transmitted light amount of the entire display means is attenuated. Therefore, the brightness of the display image can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an image display device 1 according to an embodiment of the present invention, FIG. 2 is a sectional view showing a configuration example of a display means 6,
FIG. 3 is an enlarged plan view of a part of the liquid crystal display element 10, FIG. 4 is a cross-sectional view illustrating a manufacturing process of the display means 6, and FIG. 5 is a plan view illustrating the manufacturing process. 1 ... Image display device, 2 ... White light source, 6 ... Display means, 9 ... Color selection member, 10 ... Liquid crystal display element, 11, 19,
20 …… glass substrate, 13 …… picture element electrode, 17 …… transparent region,
18 ... Shading area, 22 ... Micro lens, 23R, 23G, 23B
...... Color filter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Hamada 22-22 Nagaike-cho, Abeno-ku, Osaka City, Osaka Prefecture Sharp Corporation (56) References JP-A-3-51882 (JP, A) JP-A-2- 115889 (JP, A) Actual development Sho 60-80492 (JP, U)

Claims (1)

(57) [Claims] 1. A light source, display means for arranging display pixels for selectively transmitting light from the light source in a matrix, and a light-shielding area formed around each display pixel, and the display means. A light-transmitting substrate provided on the light source side of the light-transmitting substrate and formed by embedding a plurality of microlenses. And a translucent substrate on which a color selection member for selecting a predetermined color is formed.The color selection member of the translucent substrate faces each display picture element of the display means and transmits light between them. A color image display device characterized in that light to be incident on a display element and a light shielding region from a light source, which is filled with a conductive material, is condensed only on a display pixel by a microlens.