JPH03184020A - Liquid crystal display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid crystal display device. More specifically, the present invention relates to, for example, an active matrix liquid crystal display device.

Conventional technology Thin film transistors (T
I+in Film Transistor, hereinafter referred to as TP
An active matrix type liquid crystal display device using a display electrode substrate formed by arranging electrodes (abbreviated as T) in a matrix has a fast response speed of the liquid crystal, and there are restrictions on the area of the insulating substrate used as the display electrode substrate. However, it has the advantage that it can be applied to both reflective and transmissive types, so it is considered promising as a large-capacity display device.

FIG. 3 is a sectional view schematically showing the conventional structure of such an active matrix color liquid crystal display device.

In FIG. 3, a plurality of transparent picture element electrodes 2 and a plurality of TFTs 3 connected to each transparent picture element electrode 2 in a one-to-one correspondence are arranged in a matrix on a transparent insulating substrate 1. It is formed.

On the other hand, on the surface side facing the other transparent insulating substrate 1 of another transparent insulating substrate 4 disposed opposite to the transparent insulating substrate 1, color filters 5 are provided at positions facing each transparent picture element electrode 2. are formed, and a light shielding layer 6 is formed at a position facing each TFT 3 and a pass line (not shown). Furthermore, a common electrode 7 is provided on the entire surface.
is formed.

A liquid crystal layer 8 is interposed between these two substrates, and the liquid crystal layer 8 is sealed by a seal member (not shown).

Also, the common amount f of the transparent insulating substrate 4! An upper polarizing plate 9 is disposed on the surface opposite to the surface on which the transparent picture element electrodes 2 are formed, and a lower polarizing plate 9 is disposed on the surface opposite to the surface on which the transparent picture element electrodes 2 are formed on the other transparent insulating substrate 1. has been done.

Further, a backlight source 11 is arranged on the side where the upper polarizing plate 9 is arranged on the transparent insulating substrate 4 .

In the above color) α-crystal display device, the light shielding layer 6 allows backlight light to pass through the gap between the color filters 5,
This is provided in order to prevent not only the color filter corresponding to the picture element part but also the peripheral part from emitting light and reducing the contrast.

Problems to be Solved by the Invention In such a conventional liquid crystal display device, a part of the backlight light is reflected by the light shielding layer 6 without being transmitted, so it does not contribute as a backlight, and the light source cannot be used effectively. The problem is that there is no.

In particular, current efforts are being made to increase the density of display in liquid crystal display devices, and as a result, the aperture ratio, which indicates the area of a display picture element portion relative to the unit area of a picture element, tends to decrease. This is because as the display density increases, the display pixel portion corresponding to the transparent pixel pole 2 becomes smaller, while the source path lines and gate path lines remain almost the same size. This is due to the fact that the size of the light shielding layer 6 provided above the exclusive portion of the line or gate pass line is almost the same size.

When the aperture ratio is reduced in this way, there is a problem that the displayed image becomes dark and loses its sharpness when the brightness of the backlight is the same as before the aperture ratio was reduced.

Therefore, an object of the present invention is to make effective use of the backlight light blocked by the light blocking layer 6 to make displayed images bright and sharp.

Means for Solving the Problems The present invention provides a liquid crystal display device having a light shielding layer formed between picture elements. This is a liquid crystal display device characterized by arranging a light condensing material corresponding to each picture element.

Function According to the present invention, the backlight light, which was hitherto irradiated onto the light-shielding layer and was blocked and did not contribute to the brightness of the displayed image, is refracted and irradiated onto the display pixel portion by the light condensing material. By effectively using the light emitted from the backlight in this way, the reduction in image brightness caused by the reduction in aperture ratio that accompanies the increased display density of liquid crystal display devices can be alleviated, making it possible to obtain bright and sharp images. can.

Embodiment 1 (2I is a schematic cross-sectional view of a liquid crystal display device that is an embodiment of the present invention.

That is, in the first [N], on the transparent insulating substrate 1, a plurality of transparent picture element electrodes 2 and a plurality of TFTs 3 connected to each transparent picture element electrode 2 on a one-to-one basis with an interval of 1 inch are arranged in a matrix form. It is formed by arranging.

On the other hand, on the surface side facing the other transparent insulating substrate 1 of another transparent insulating substrate 4 disposed opposite to the transparent insulating substrate 1, a backlight is provided at a position facing each transparent picture element electrode 2. Of these, red (R), green (G), blue (
A color filter 5 is formed that transmits only one of the wavelengths of light of B). In addition, a light shield M6 is formed at a position facing each TFT 3 and a pass line (not shown). Further, a common electrode 7 is formed on the entire surface of the color filter 5 and the light shielding layer 6.

A liquid crystal layer 8 is interposed between these two substrates, and the liquid crystal layer 8 is sealed by a seal member (not shown).

Further, an upper polarizing plate 9 is disposed on the surface of the transparent insulating substrate 4 opposite to the surface on which the common electrode 7 is formed, and an upper polarizing plate 9 is disposed on the surface of the other transparent insulating substrate 1 on the opposite side to the surface on which the transparent picture element electrode 2 is formed. A side polarizing plate 10 is arranged.

Further, on the surface of the upper polarizing plate 9 on the side opposite to the transparent insulating substrate 4 side, a condensing material 1 or a convex lens, for example, is arranged so that each transparent picture element corresponds to the pole 2, and a backlight source is placed above it. Place 11.

In the conventional liquid crystal display device, the backlight light that is irradiated onto the light shielding layer 6 indicated by the symbol Wl in FIG. 1, does not pass through, and does not contribute to the brightness of the displayed image. As shown by the arrow mark 13, the light can be refracted and irradiated onto the color filter 5 by the condensing material 12 in the same way as the light irradiated onto the area shown by the reference numeral W2 in FIG. As a result, the backlight light that was lost in the light-shielding layer 6 can be effectively used, the darkening of the displayed image due to the reduction in the aperture ratio is improved, and a bright display can be obtained.

Furthermore, in the liquid crystal display device of this embodiment having a structure in which the above-described backlight source 11, light condensing material 12, and upper polarizing plate 9 are laminated in this order, heat from the backlight source 11 is transferred to the light condensing material 12. It is possible to prevent the upper polarizing plate 9 from deteriorating due to a temperature rise.

FIG. 2 is a plan view of the above-described liquid crystal display device. Second
In the figure, source bus electrodes 14 are formed parallel to each other at equal intervals, and gate bus electrodes 15 are also formed parallel to each other at equal intervals. These source bus electrodes 14 and gate bus electrodes 15 are arranged to cross each other at right angles with an insulating film interposed therebetween.

A TPT 3 is formed at each intersection of the source bus electrode f114 and the gate bus electrode 15, and the transparent picture element electrode 2 corresponding to each picture element of the liquid crystal display device is connected to the source bus electrode 1.
4 and the gate bus electrode 15 are formed so as to substantially fill these regions. The source electrode of TPT is the source bus electrode 14, the gate electrode is the gate bus electrode 15, and the drain electrode is the corresponding transparent picture element electrode f! 2 are connected to each other.

In the figure, the source bus electrode 14 is indicated by a diagonal line extending from the upper right to the lower left, and the gate bus electrode 15 is indicated by a diagonal line extending from the upper left to the lower right.

A brief overview of the operation of the liquid crystal display device of the present invention is as follows.

In the liquid crystal display device of the present invention, switching of the TPT 3 is controlled by the voltage applied from each pass line 14 and 15, and by controlling the voltage applied between the common electrode 7 and the TPT 3, the voltage applied to the liquid crystal 8 for each pixel is controlled. Control voltage. At this time, as a characteristic of liquid crystal,
When a voltage is applied, the liquid crystal molecules are arranged uniformly in the 1 (up and down) direction, and the backlight light that has passed through the upper 1 polarizing plate 9 passes through the liquid crystal 8, at which time the plane of polarization is rotated by 90 degrees. . Therefore, if the lower polarizing plate 10 is arranged with its polarization plane shifted by 90 degrees with respect to the upper polarizing plate 9, the backlight light will pass through the liquid crystal display device when the above-mentioned voltage is applied.

Conversely, when no voltage is applied to the liquid crystal 8, the liquid crystal molecules remain randomly arranged and the incident light is reflected diffusely, so that it is not transmitted.

Effects of the Invention As described above, according to the liquid crystal display device of the present invention, in order to cope with the decrease in aperture ratio due to the increase in the density of picture elements in liquid crystal display devices, it is possible to reduce the amount of light incident on the light shielding layer on the backlight light incident side. Insufficient brightness of displayed images can be improved by arranging a condensing lens for refraction in the picture element portion and effectively utilizing backlight light.

The liquid crystal display device of the present invention is suitable for use as a viewfinder, which is a liquid crystal display device included in a television camera so that an operator can visually check images captured by the television camera. This is particularly useful because viewfinders are naturally required to be small, and therefore liquid crystal display devices with high pixel density are required.

For example, in the case of a liquid crystal display device with a diagonal of 1 inch and 70,000 pixels, the pixel pitch is approximately 60 μm, and the total light-shielding layer portion is 20 μm.
If m, the display picture element portion will be 40 μm, and therefore the aperture ratio will be approximately 40%. In order to further increase the density, it would be difficult to make each pass line width extremely small.

This is because the display detection portion becomes narrower and the aperture ratio becomes smaller, resulting in a darker displayed image. In such a case, by using the liquid crystal display device of the present invention, backlight light can be used effectively and a bright display can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a liquid crystal display device according to an embodiment of the present invention, second numeral 21 is a plan view of the liquid crystal display device, and FIG. 3 is a sectional view of a conventional liquid crystal display device.

Claims (1)

[Scope of Claims] In a liquid crystal display device having a light-shielding layer formed between picture elements, each picture element is provided on the light source side of the light-shielding layer, directly above the picture element and across the light-shielding layer of that picture element. A liquid crystal display device characterized in that a light condensing material corresponding to the above is arranged.