JPH0651311A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide the structure of the liquid crystal display device which is extremely high in lighting efficiency by increasing the directivity of light by a microlens array. CONSTITUTION:On one glass substrate 22 of a liquid crystal panel 2, pixel electrodes 4, TFTs 5, and wirings 6 are manufactured corresponding to respective pixels. On the opposite surface from the surface where the TFTs 5 are manufactured, a metallic mask 7 is formed so that opening parts at the parts of the pixel electrodes 4 transmit light and light at the parts of the TFTs, electrodes, etc., is not transmitted. The surface of the metallic mask 7 on the side of a fluorescent lamp 1 is formed into a reflecting surface so as to reflect illumination light. On the surface of the glass substrate 22 on the opposite side from a liquid crystal layer 3, the microlens array 9 is provided having respective lenses corresponding to the pixel electrodes 4 one to one. Further, an oblique mirror array 10 equipped with many reflecting oblique surfaces is provide on the fluorescent lamp 1 on the opposite side from the liquid crystal panel 2. This oblique mirror array 10 serves to direct reflected light from the reflecting surfaces on the liquid crystal panel substrate to the pixel opening parts by changing its travel direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device useful for laptop personal computers, notebook personal computers and the like.

[0002]

2. Description of the Related Art A conventional liquid crystal display device of this type illuminates a liquid crystal panel from the back with a backlight having a light source such as a fluorescent lamp, and a pattern is formed by the difference in the transmittance of each pixel of the liquid crystal panel of the backlight illumination. , Display the image. At this time,
In general, a liquid crystal panel has a large area occupied by TFTs (thin film transistors) and wirings, so that the ratio of the area of the pixel opening to the total area of the liquid crystal panel is not so high. That is, when the ratio of the opening area to the area of one pixel is called the aperture ratio, the aperture ratio of the liquid crystal panel is generally 30 to 4
It is as low as 0%, and the remaining illumination light cannot be used.

[0003]

As described above, it is difficult to increase the brightness of the liquid crystal panel in the conventional device, and if an illumination light source with a large light output is used to improve the brightness, power consumption increases. There was a problem.

[0004]

In a device of the present invention, a diffused illumination light source, a liquid crystal panel having a plurality of pixel openings arranged one-dimensionally or two-dimensionally, and the pixel openings have a one-to-one correspondence.
And an array of microlenses arranged in large numbers facing each other. The illumination light source, the pixel aperture, and the microlens array are arranged in this order, and each lens of the microlens array has a function of narrowing the divergence angle of the light beam diverging / emitting from the pixel aperture. Further, a reflector is provided in a portion of the surface of the liquid crystal panel on the side of the illumination light source other than the pixel opening portion, and an optical means for changing the traveling direction of the reflected light on the reflection surface is provided near the illumination light source.

[0005]

According to the present invention, the directivity of light can be improved by the microlens array, and the light which has not been transmitted through the liquid crystal aperture can be utilized by the combination of the reflecting surface and the light traveling direction changing means. Therefore, an extremely bright liquid crystal display device can be realized.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. In FIG. 1, a liquid crystal panel 2 is a fluorescent lamp 1.
The so-called backlight illumination is performed by the white illumination. The liquid crystal panel 2 has a structure in which a liquid crystal layer 3 is sandwiched between a pair of glass substrates 21 and 22, and a pixel electrode 4, a TFT 5 and a wiring 6 are formed on one glass substrate 22 in correspondence with each pixel. There is.

Of these, the TFT 5 and the wiring 6 are portions that do not transmit light, and since the temperature rises when exposed to light, they cannot be used in practice, and the openings that transmit light are transparent. It is only the portion of the pixel electrode 4. Therefore, on the surface opposite to the surface on which the TFT 5 is formed, a metal mask 7 is applied so that the pixel electrode 4 portion transmits light as an opening and the TFT, the electrode, and the like do not transmit light. is there.

The surface 7A of the metal mask 7 on the fluorescent lamp 1 side is a reflecting surface so as to reflect the illumination light. The metal mask 7 can be manufactured by sputtering or vapor-depositing a thin film of Cr or Al on the glass substrate 21 and removing the film in the portion facing the pixel electrode 4 by the photolithography technique. A transparent conductive film 8 made of ITO or the like is formed on the metal mask 7.

A microlens array 9 is provided on the surface of the glass substrate 22 opposite to the liquid crystal layer 3, with each lens corresponding to the pixel electrode in a one-to-one correspondence. The micro lens array 9 is
For example, it can be manufactured as an array of gradient index lenses by an ion exchange method. In addition to directly forming the lens array in the liquid crystal cell substrate as described above, the microlens array 9
May be manufactured as a separate glass plate and adhered to the glass substrate 22.

Further, an oblique mirror array 10 having a large number of reflective inclined surfaces is provided on the side of the fluorescent lamp 1 opposite to the liquid crystal panel 2. The oblique mirror array 10 has a function of changing the traveling direction of the reflected light by the reflecting surface 7A on the liquid crystal panel substrate and directing it toward the pixel opening.

Of the illumination light emitted from the fluorescent lamp 1, a light ray (for example, a light ray 100) incident on a pixel opening portion (light transmitting portion of the metal mask 7) has a narrow directivity due to the microlens array 9 and thus the liquid crystal panel. Eject from 2. On the other hand, a light ray (for example, the light ray 101) that enters the portion of the illumination light other than the pixel aperture is reflected by the reflecting surface 7A of the metal mask 7 and is reflected by the oblique mirror array 10 in different directions, and then the aperture is opened. Then, the light enters the liquid crystal panel 2 and is transmitted through the liquid crystal panel 2. Of course, all such reflected light does not enter the opening, but it is possible to greatly improve the brightness in consideration of multiple reflection.

[0012]

As described above, according to the present invention, illumination light incident on a portion other than the opening, which cannot be used conventionally, can be used, and since the directivity of the light beam emitted from the liquid crystal panel can be narrowed, the light within that angle can be used. An extremely bright liquid crystal display device with increased strength can be realized. Therefore, bright display is possible even with a relatively low-luminance fluorescent lamp, and low power consumption can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 1 Fluorescent Lamp 2 Liquid Crystal Panel 3 Liquid Crystal Layer 4 Pixel Electrode 5 TFT 6 Wiring Part 7 Metal Film 7A Reflecting Surface 8 Transparent Conductive Film 9 Microlens Array 10 Oblique Mirror Array 21 Glass Substrate 22 Glass Substrate 100 Light Emitting Light from Fluorescent Lamp 101 Fluorescent Light rays emitted from a lamp

Claims (5)

[Claims] 1. A diffused illumination light source, a liquid crystal panel having a plurality of one-dimensionally or two-dimensionally arranged pixel openings, and an array of a plurality of microlenses arranged in one-to-one correspondence with the pixel openings. And a light source, a pixel aperture, and a microlens array are arranged in this order, and each lens of the microlens array narrows a divergence angle of a light beam diverging / emitting from the pixel aperture. Has a function and
The liquid crystal panel is provided with a reflector in a portion other than the pixel opening portion on the illumination light source side, and further provided with optical means for changing the traveling direction of the reflected light on the reflection surface in the vicinity of the illumination light source,
Therefore, at least a part of the reflected light reaches the pixel opening again. 2. The liquid crystal display device according to claim 1, wherein the optical means for changing the traveling direction of the reflected light is a mirror array having a plurality of oblique reflecting surfaces. 3. The liquid crystal display device according to claim 1, wherein the optical means for changing the traveling direction of the reflected light is a light diffusion plate. 4. The reflector on the surface of the liquid crystal panel is a metal film such as Cr or Al coated on one of the two glass substrates forming the liquid crystal panel. 5. The liquid crystal display device according to any one of 3 and 3. 5. The liquid crystal display device according to claim 1, wherein the microlens array is an array of gradient index lenses formed near the surface of a glass substrate.