JPH05100222A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal panel which effectively utilizes the light of a light source by totally reflecting light, which irradiates a black matrix, as to light which is made incident on a glass substrate by a slanting surfaces of a groove and making it incident on a peripheral picture element area. CONSTITUTION:An active switching element 4, a picture element electrode 5 or a common electrode 6 are formed on the surfaces of glass substrates 2 and 3 between which a liquid crystal layer 1 is sandwiched. The black matrix for contrast improvement is formed on this liquid crystal panel. On the light incidence side substrates between the substrates between which the liquid crystal is sandwiched, the groove 11 which has the surface for totally reflecting the incident light is formed opposite the formation position of the black matrix to constitute the liquid crystal display device.

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, and more particularly to improving the aperture ratio of a liquid crystal panel.

[0002]

2. Description of the Related Art As shown in FIG. 3, a liquid crystal display device has a structure in which a liquid crystal layer 1 is sandwiched between two glass substrates 2 and 3. On the surface of the glass substrate 2, an active element 4 and a pixel electrode 5, which are made of, for example, a TFT (thin film transistor), for selecting each pixel and applying a voltage to a liquid crystal layer, and a driving signal is supplied to these elements. Wiring is formed. On the surface of the other glass substrate 3, a common electrode 6 for applying a predetermined drive voltage to the liquid crystal is formed between the glass substrate 3 and the pixel electrode 5. By inputting a signal to the active element 4 and switching it, the pixel electrode 5
Is selected, a drive voltage is supplied, and the common electrode 6 facing each other is selected.
A drive voltage is applied to the liquid crystal layer located between the and, and contributes to display as a pixel.

[0003]

The liquid crystal display device having the above structure has the following structure when a drive voltage is applied to a selected pixel.
Since the voltage is applied to the selected pixel and the same voltage is applied to the wiring connected to this pixel, the voltage corresponding to the drive voltage is also applied to the liquid crystal layer located between the common electrode facing the pixel. It will be added and the display state will be exhibited. This reduces the contrast of the pixels and thus the quality of the image. Therefore, in this type of liquid crystal display device, the contrast is usually improved by forming a light-shielding black matrix 7 at the boundary between adjacent pixels to block light from the wiring portion and the like.

Although the contrast is improved by the above improvement, since the light incident on the black matrix 7 portion does not contribute to the display of an image, the utilization factor of the light is poor, and for the liquid crystal display device having no self-luminous ability, the black matrix portion. The inability to use this light increases the burden on the backlight, and the improvement of the aperture ratio is a problem.

The present invention has been made in view of the above problems of the conventional device, and provides a liquid crystal display device in which the aperture ratio is improved without impairing the contrast.

[0006]

In order to achieve the above object, the present invention forms electrodes and wirings for applying a driving voltage to liquid crystal of a selected pixel portion, and shields light at the boundary of each pixel. In the liquid crystal display device in which the black matrix is formed, a groove having a surface that reflects incident light is formed in the glass substrate on the side where the light is incident, at a position facing the position where the black matrix is formed. A liquid crystal display device is configured.

[0007]

Since the surface of the glass substrate facing the black matrix is formed to reflect the incident light, the light incident on the black matrix is reflected and enters the surrounding pixel area. In addition to the original incident light, the pixel area also contributes to the light of the black matrix portion for display, and a display panel having a high aperture ratio can be obtained. Particularly, in the color liquid crystal display panel, since the filters are overlapped with each other, the utilization factor of light is further lowered, which can be compensated.

[0008]

1 is a cross-sectional view of a liquid crystal panel showing an embodiment of the present invention, and FIG. 2 is an enlarged view of a main part of the same embodiment.
The liquid crystal layer 1 is sandwiched between two glass substrates 2 and 3 facing each other. On the surface of the glass substrate 2, pixel electrodes 5 and switching elements 4 connected to the pixel electrodes for active matrix driving are formed in a matrix. On the other hand, on the other glass substrate 3 side, a common electrode 6 is commonly formed so as to cover the surface of the glass substrate 3. On the surface of the glass substrate 3, on the common electrode 6,
A black matrix 7 is formed at a portion of each pixel on the glass substrate 2 side which is adjacent to each other, and R, R is formed so as to contact the boundaries within the width of the black matrix 7.
G and B color filters 8 are formed. Alignment films and the like are formed on the surfaces of the glass substrates 2 and 3 on which the electrodes for driving the liquid crystal are formed, as is conventionally done, and the polarizing plates 9 and 10 are formed on the outer surfaces of both substrates. Are stacked.

In the liquid crystal panel having the above structure, in order to increase the aperture ratio, V is provided on the glass substrate on the side where the light from the backlight is incident, in this embodiment, the glass substrate 2 side on which the active switching element 4 is formed. The groove 11 is carved. That is, a V groove 11 having a groove width that substantially covers the width of the black matrix 7 is formed at a position of the glass substrate 2 facing the position of the black matrix 7 formed on the glass substrate 3. As shown in FIG. 2, the V groove 11 irradiates the groove slope 11 </ b> A with the light L from the backlight that is directed toward the black matrix 7 and totally reflects the light L, and the light L is incident on the surrounding pixel regions. Then, the light incident on the original pixel region is added to pass through the liquid crystal layer, and the light of the backlight light source is effectively used for display. The groove 11 can be formed by chemical etching or physical processing, and the removed V groove 11 has a reflection condition described later for the incident light on the glass substrate 2. The material that can satisfy the above is filled.

The V-shaped groove 11 is processed to have dimensions satisfying the following conditions. The incident angle of the backlight light L incident on the glass substrate 2 on the V groove wall 11A is θ, the pitch of the black matrix 7 is p, and the black matrix 7 is
And the refractive index of the glass substrate 2 is n,
When the refractive index inside the V groove is N, the critical angle I is I = sin
It is represented by ^-1 N / n. In order to cause total reflection, it is necessary to increase the incident angle θ with respect to the critical angle I. Based on the angle θ thus determined, the shape of the V-shaped groove 11, that is, the height h is determined from the shape of the black matrix 7 already given by the following equation. x and y are V
The coordinates of the groove are shown. tan = 2h / (p-s) y = {2h / (s-p)} x + h

In the above-mentioned embodiment, the V groove 11 is formed around the respective pixels and formed along the entire black matrix portion of the panel. However, as the display pixels, four active switching elements are provided. In consideration of the fact that the amount of incident light is reduced due to the fact that pixels are embedded in the pixel region and the pixels are chipped, it can be implemented as a panel structure in which V-grooves are formed at the black matrix position covering at least the switching element portion. .. With this structure, the incidence of light that decreases due to the formation of the switching element can be compensated.

Further, the panel structure in which the backlight light is incident from the active switching element side 2 has been described, but the invention can be applied to the panel in which the backlight light is incident from the common electrode side 3. Further, the present invention can be applied not only to the case where parallel light rays are emitted from a light source, but also to a panel which is illuminated with diffused light and other light.

[0013]

According to the present invention, by processing the V-grooves on the glass substrate, the aperture ratio can be improved without impairing the contrast improvement by the black matrix, and the light utilization rate is increased, and the liquid crystal display device is improved. It is possible to reduce the burden on the light source, which is a problem of the above.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of a main part of the embodiment.

FIG. 3 is a cross-sectional view of a conventional device.

[Explanation of symbols]

 1 Liquid Crystal Layer 2, 3 Glass Substrate 4 Active Switching Element 5 Pixel Electrode 6 Supply Electrode 7 Black Matrix 11 V-Groove

Claims (2)

[Claims] 1. A liquid crystal display device in which electrodes and wirings for applying a driving voltage are formed on the liquid crystal of a selected pixel portion, and a light-shielding black matrix is formed at the boundary of each pixel, in which light is incident. 2. The liquid crystal display device according to claim 1, wherein a groove having a surface that reflects incident light is formed at a position facing the black matrix formation position. 2. The liquid crystal display device according to claim 1, wherein the groove is formed at a black matrix position that covers at least the active switching element.