JPH04134321A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To increase the utilization efficiency of light and to improve the brightness of a display image by converging the light from a light source through convex lenses in picture element units and guiding the light to the respective picture elements of a liquid crystal panel. CONSTITUTION:On at least one surface of each picture element of the liquid crystal panel P, a convex lens 5 which is larger than the area of each picture element is provided, and the light from the light source L is converted by the lens 5 and guided to each picture element of the liquid crystal panel P. further, the convex lens 5 uses a convex lens in an aspherical and asymmetrical sectional shape so as to have focus in a direction along the high-contrast axis direction of the liquid crystal panel. Consequently, the high-contrast axis direction is set apparently perpendicular to the liquid crystal panel P and the utilization efficiency of the light is greatly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a liquid crystal display device, and particularly to a liquid crystal projector using a liquid crystal panel as an original image.

(b) Prior Art In recent years, liquid crystal projectors using liquid crystal panels have become popular as devices that can easily display large images. Currently, most liquid crystal panels used in such liquid crystal projectors are active matrix type panels that have good display characteristics such as contrast and response.

However, in the case of active matrix liquid crystal display panels, one active element, such as a TPT (thin film transistor) or a nonlinear element with an MIM structure, is built into each pixel, so the effective pixel aperture ratio tends to be small. .

Therefore, when a liquid crystal projector is constructed using such a liquid crystal panel, the effective pixel aperture ratio is small, so the light utilization efficiency is low, and the display image obtained on the screen cannot have sufficient brightness. There were drawbacks.

It is thought that this drawback can be alleviated to some extent by using a high-brightness light source for the liquid crystal projector.
In this case, the power consumption of the entire device increases, or
There was a concern that the high heat generated by the use of a high-intensity light source would impede the operating characteristics of active elements in active matrix liquid crystal display panels.

On the other hand, in a normal liquid crystal display panel as shown in FIG. 4, the angle (
For example, about 6 degrees), there is a preferred viewing angle direction (high contrast axis direction) indicated by an arrow. In the figure, l is a transparent pixel electrode substrate, 2 is a transparent counter electrode substrate, and 3 is a sealant that seals the periphery of both of these substrates, and a liquid crystal 4 is inside the cell constituted by these. It is enclosed. This liquid crystal 4 has a light-shielded portion 40 (position 71 in the figure) that is light-shielded by a light-shielding mask provided on the counter electrode substrate.
Pixel separation is performed in

When configuring a projector using a liquid crystal panel with such a high contrast axis direction, as shown in the schematic configuration diagram in Fig. This panel will be installed diagonally to match the viewing direction. That is, the parallel light from the light source lens R1, which converts light from the light source into parallel light, is efficiently transmitted along the preferred viewing angle direction of the obliquely provided panel P, and this transmitted light is transmitted through the enlarged projection lens R2. and is projected onto the screen S.

In such a projector, the liquid crystal panel P must be arranged at an angle, which not only has the drawback of complicating the structure of the device, but also poses a risk that adjustment of the angle of inclination of the panel P may become complicated. .

(c) Problems to be Solved by the Invention The present invention has been made in view of the above-mentioned drawbacks, and includes:
An object of the present invention is to provide a liquid crystal display device that improves light utilization efficiency and provides a brighter screen to eliminate the drawback that sufficient brightness cannot be obtained for displayed images.

Further, the present invention provides a liquid crystal display device in which the high contrast axis direction can be apparently perpendicular to the liquid crystal panel.

(d) Means for Solving the Problems The liquid crystal display device of the present invention combines a light transmission type liquid crystal panel that adjusts the amount of transmitted light for each of a large number of pixels arranged in rows and columns with a light source. A convex lens having an area larger than the area of each pixel is provided on at least one side of each pixel, and a structure is provided in which the convex lens condenses light from a light source and supplies it to each pixel of the liquid crystal panel.

Further, the liquid crystal display device of the present invention uses an aspherical asymmetrical cross-sectional convex lens as the convex lens so as to have a focal point in a direction along the high contrast axis direction of the liquid crystal panel.

Further, in the liquid crystal display device of the present invention, the liquid crystal panel is provided with a light-shielding mask for blocking light leakage from areas other than pixels, and the convex lens is attached to a photocurable resin coated on the entire surface of the liquid crystal panel. On the other hand, it is formed by exposure patterning using light transmitted through the liquid crystal panel itself.

(E) Function According to the liquid crystal display device of the present invention, the light from the light source is condensed by the convex lens and supplied to each pixel of the liquid crystal panel, so the efficiency of light utilization is greatly increased.

Further, according to the liquid crystal display device of the present invention, a pair of aspherical asymmetric light condensing convex lenses can be arranged in front and behind the liquid crystal panel, corresponding to each pixel. Due to this lens shape, the incident light is refracted along the high contrast axis direction of the liquid crystal panel, and the outgoing light from this panel is refracted again and transmitted as light in the same direction as the incident light, that is, parallel light. Become.

Furthermore, according to the liquid crystal display device of the present invention, the inter-pixel light-shielding mask that is originally provided in the liquid crystal panel in order to improve display contrast can be used to form the above-mentioned lenses. That is, by exposing and patterning the photocured citrus resin coated on the liquid crystal panel with the light that has passed through the liquid crystal panel with the inter-pixel light-shielding mask, an aspherical asymmetrical cross-sectional convex lens can be obtained.

(F) Embodiment FIG. 1 shows a sectional view of a liquid crystal panel of a liquid crystal display device of the present invention. In the figure, 1 is a transparent pixel electrode substrate, 2 is a transparent counter electrode substrate, 3 is a sealant that seals the periphery of both substrates, 4 is a liquid crystal, and 40 is provided on the counter electrode substrate 2. The portions (hatched positions in the figure) blocked by the light blocking mask are shown, and these may be the same as the conventional device shown in FIG. 4.

The liquid crystal display device of the present invention shown in the same figure is different from the conventional device shown in FIG. The convex lenses 5.5 condense light from the light source and supply it to each pixel.

Furthermore, the convex lenses 5.5... are formed with an aspherical asymmetrical cross-sectional shape so as to have a focal point in the direction along the high-contrast direction axis of the liquid crystal panel. The incoming light is condensed and refracted in the high-contrast axis direction, and the outgoing light from the panel P is again condensed by the convex lens 5.5 and refracted in the direction perpendicular to the panel P. Become.

Therefore, when such a liquid crystal panel P is adopted in a projector, as shown in the schematic configuration diagram in FIG. can be matched. That is, the parallel light from the light source lens R1, which converts the light from the light source into parallel light, is efficiently transmitted along the apparent high-contrast axis direction of the vertically arranged panel P, and this transmitted light is transmitted through the enlarged projection lens. It is projected onto the screen S via R2.

In a liquid crystal panel using an active switching element such as TPT or MIM, the aperture ratio of the pixel becomes small depending on the size of the element and the wiring, and therefore the light transmittance becomes small, but in the liquid crystal display device of the present invention, The lens 5. is arranged on the surface of the pixel without wasting the light irradiated to the aperture of the pixel, that is, the part other than the effective display area.
The light is focused by 5. and passed through the pixel aperture along the high-contrast axis direction of the liquid crystal, and after passing through the panel, it can be further parallelized by lens 5.5, which improves the efficiency of light utilization. is greatly improved.

Next, an example of a manufacturing method for the lenses 5,5, etc. described above will be outlined based on FIGS. 3(a) and 3(b).

First, as shown in FIG. 3(a), a polarizing plate (not shown) is attached to one surface of the liquid crystal panel P, and an ultraviolet curing resin is applied to the polarizing plate. Light is irradiated from the opposite side. The light irradiated in this way is transmitted only to the pixel area by a light-shielding mask that blocks light leakage from areas other than the pixel, and this transmitted light has a high contrast inside the panel P, as shown by the arrow in the figure. The light is refracted in the axial direction and is incident on the ultraviolet curable resin layer, where it is cured.

Note that the light irradiation at this time is from the opposite side of panel P.
However, in order to obtain an aspherical asymmetric cross-sectional shape that is larger than the pixel area, additional light is irradiated from an angle slightly offset from the perpendicular direction to the panel P. .

In this way, an array of lenses 5, 5, . . . can be manufactured on one surface of the liquid crystal panel P, as shown in FIG.

Furthermore, if a lens array is to be formed on the other side of the liquid crystal panel P, the first lens array shown in FIG. Then, with a second polarizing plate attached to the other surface, an ultraviolet curable resin is applied onto this polarizing plate, and exposure patterning is performed in the same manner as described above to form a second lens array. do. Then, the first lens array may be attached to one surface of the panel P again.

(G) Effects of the Invention The liquid crystal display device of the present invention has a structure in which the light from the light source is collected by a convex lens for each pixel and supplied to each pixel of the liquid crystal panel, so the efficiency of light utilization is increased and the display The brightness of the image can be increased.

Furthermore, according to the liquid crystal display device of the present invention, since a pair of aspherical asymmetric condensing convex lenses can be arranged for each pixel in front and behind the liquid crystal panel, the incident light is directed along the high contrast axis direction of the liquid crystal panel. The light emitted from this panel is refracted and transmitted in the same direction as the incident light, that is, as parallel light. Using this, the structure of the projector can be simplified and miniaturized. .

Furthermore, since the inter-pixel light-shielding mask that is originally provided in the liquid crystal panel to improve display contrast can be used to form the above-mentioned lenses, the liquid crystal display device of the present invention can be realized by a simple manufacturing method.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a liquid crystal panel used in the liquid crystal display device of the present invention, Fig. 2 is a conceptual configuration diagram of a projector equipped with the liquid crystal display device of the present invention, and Fig. 3 shows the manufacturing process of the device of the present invention. 4 is a sectional view of a conventional liquid crystal panel, and FIG. 5 is a conceptual diagram of a conventional projector. 4...Liquid crystal, 5...Lens, 50...Ultraviolet curing resin layer, P...Liquid crystal panel.

Claims (3)

[Claims] (1) In a liquid crystal display device that combines a light transmission type liquid crystal panel that adjusts the amount of transmitted light for each of a large number of pixels arranged in rows and columns with a light source, at least one side of each pixel of the liquid crystal panel has an area larger than the area of each pixel. A liquid crystal display device comprising a convex lens having a large area, the convex lens condensing light from a light source and supplying it to each pixel of a liquid crystal panel. (2) A liquid crystal display device according to claim 1, wherein the convex lens is formed to have an aspheric asymmetric cross-sectional shape so as to have a focal point in a direction along a high contrast direction axis of the liquid crystal panel. (3) In the liquid crystal display device according to claim 1 or 2, the liquid crystal panel is provided with a light shielding mask for blocking light leakage from areas other than pixels, and the convex lens is arranged on the entire surface of the liquid crystal panel. A liquid crystal display device that is formed by exposing and patterning a photocurable resin coated on the liquid crystal panel using light that has passed through the liquid crystal panel itself.