JPH0570828B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an illumination device for a liquid crystal display element that can be used in a large screen display device comprising a plurality of transmissive liquid crystal display elements.

Conventional configurations and their problems In recent years, in addition to large-screen display devices that use three primary color fluorescent lamps or three primary color cathode tubes (CRTs), liquid crystals are used as light switches to display three primary color displays. A method using color filters is being considered.

A conventional illumination system for a liquid crystal display element will be described below with reference to the drawings.

In FIG. 2 for explanation, a white fluorescent lamp 4
When the light emitted from the liquid crystal display (LCD) 1 enters the liquid crystal display (LCD) 1, the LCD adjusts the amount of light passing therethrough according to an external signal and enters the color filter 3 layer.

The filter consists of three color filters B, G, and R (B, G, and R refer to color filters for converting white light into blue light, green light, and red light, respectively) corresponding to one picture element. The light that has passed through this is mixed again in an additive manner to form color picture elements, and a color image is displayed on the front panel 5 at position 7.

The size of a single liquid crystal display element that can currently be manufactured is from 6 inches to 12 inches square, and to construct a larger screen, it is necessary to arrange multiple panels. However, since the wiring portion 2 is generally located at the edge of a liquid crystal display, there is a problem in that the joint 6 appears as a black line (FIG. 3, 8) in a large screen display.

OBJECTS OF THE INVENTION The lighting device for a liquid crystal display device of the present invention relates to a lighting device for a liquid crystal display device that prevents the joints between a plurality of liquid crystal displays from becoming obvious even when a plurality of liquid crystal displays are used.

Structure of the Invention In order to form a large screen liquid crystal display element by arranging a plurality of transmissive liquid crystal display elements, the lighting device for a liquid crystal display element of the present invention has a lower surface facing toward the liquid crystal display part at a position corresponding to the joint thereof. With the light source as the apex,
A deformed prism whose inclination gradually decreases from the apex to the bottom edge is arranged so that the illumination light enters the edge of the liquid crystal display element from an oblique direction, so that the joints are not noticeable on the front panel of the liquid crystal display element. As a result, the seams are not visible as black lines and are less noticeable.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 best illustrates the invention.

In addition to the basic components of the conventional example shown in FIG. 2, a deformed prism 10 is added. The operation of the embodiment configured as above will be described below. A beam of light 11 emitted from the illumination light source 4 is bent by the deforming prism 10 in the direction of the LCD seam,
It passes through the picture element 15 of the LCD and reaches 16 on the front panel 5. If parts 13 and 16 are placed adjacent to each other with a gap, part 1, which originally did not receive light,
3 and 16 show information about picture elements 12 and 15 on the outer edge of the LCD, so if the front panel is configured to use these as light sources and emit light in all directions,
People viewing this display from the front can see the image as if there were no LCD seams.

As described above, according to this embodiment, by adding an illumination light prism, it is possible to display a large screen with unnoticeable seams.

As shown in Figure 4, the length l of the bottom of the prism
is selected depending on how many picture elements are used for this joint. That is, where d is the length of the part without picture elements of each LCD, n is the required number of pixels, and d ₁ is the size of the pixel, then lnd ₁ +2d is obtained. The curvature R of the deformed prism decreases as the refractive index of the material of the deformed prism decreases, and as the distance L between the LCD and the front panel decreases, and decreases as the length l of the bottom portion increases. It is also possible that the curvature gradually increases as it approaches the bottom.

In the lighting device of the present invention, in addition to the general light source, prisms are arranged along the rows of a plurality of LCD plates, so that the deformed prisms are arranged in a mesh shape as shown in Fig. 5. It consists of a network of arranged prisms. The intersection between the prisms is shaped like a horizontal prism passing through a vertical prism.

Effects of the Invention As is clear from the above description, the present invention provides a prism with the liquid crystal section as the bottom surface on the illumination light side of the joint between the liquid crystal display elements.
A light beam obliquely enters the display portion near the outer edge of the liquid crystal display element, covering the seams through which no light normally passes, and providing an excellent effect of enabling display with no visible seams.

Furthermore, by using a deformed prism, it is possible to obtain an effect that the connection of images between adjacent liquid crystal blocks is extremely natural.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the basic components of the present invention, Figure 2 is a diagram showing the basic components of the present invention.
The figure shows a conventional illumination system, Figure 3 shows a display image when using the conventional illumination system, Figure 4 shows the positional relationship between the deformed prism and the front panel of the liquid crystal plate, and Figure 5 1 is a diagram illustrating the arrangement of prisms that are components of the lighting device according to the present invention. 1...Liquid crystal section, 2...Wiring section of liquid crystal section, 3...
Color filter, 4... light source, 5... front panel,
6... Joint, 7... Image display section, 8... Black line at the joint, 10... Prism, 11, 14...
...Light flux, 12,15...Pixel, 13,16...Position of adjacent picture elements on the front panel.

Claims (1)

[Claims] 1. When forming a large-screen liquid crystal display element by arranging a plurality of transmissive liquid crystal display elements, a liquid crystal display element is placed at a position corresponding to the joint of the elements, with the liquid crystal display side as the bottom surface,
A deformed prism is arranged with the light source as the apex and the inclination gradually decreases from the apex to the edge of the bottom surface, and the illumination light is incident on the edge of the liquid crystal display element from an oblique direction. An illumination device for a liquid crystal display element, characterized in that it is made inconspicuous.