JP2924895B1 - Backlight unit for liquid crystal display - Google Patents

Abstract

An object of the present invention is to provide a backlight unit that prevents erroneous insertion of a lens sheet in a process of assembling a backlight unit of a liquid crystal display device and that can confirm erroneous insertion even after unit assembly. SOLUTION: The backlight unit of the present invention has a lens sheet 6 and 7 provided with ears 8 and 9 which do not overlap each other outside the angle of view, and an optical component provided with a cutout 3 for accommodating the ears. And a support 1. The number and order of the inserted lens sheets can be visually confirmed by observing the shape of the ear of the notch 3 from a specific direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a backlight unit of a liquid crystal display device used for a personal computer or the like.

[0002]

2. Description of the Related Art Liquid crystal display devices are portable notebook computers,
Widely used for applications such as portable liquid crystal TVs. Since such a portable liquid crystal display device is driven by a battery, the power consumption of the liquid crystal display device has been an obstacle to prolonging the battery life. Above all, the power consumption of the backlight used in liquid crystal display devices is large,
The brightness of the display screen is increased with small power consumption by improving the optical efficiency of the backlight.

FIG. 7 shows a general structure of such a backlight. In FIG. 7, reference numeral 50 denotes a light source such as a cathode ray tube, which is disposed to face the side surface of the light guide plate 51. To effectively introduce light from the light source 50 to the light guide plate 51, the rear surface of the light source 50 is covered with a reflection sheet 52. Light guide plate 51
A reflection sheet 53 is provided on the lower surface of the device, and a diffusion plate 54 and lens sheets 55 and 56 are provided on the upper surface in close contact with each other to form a backlight unit 57. Backlight unit 57
A liquid crystal panel 58 is disposed above and separated by a distance to form a liquid crystal display panel unit.

Light emitted from a light source 50 is incident on a light guide plate 51, and the light propagates through the light guide plate 51 and spreads over the entire surface, and is incident on lens sheets 55 and 56 via a diffusion plate 54. The incident light is refracted in the lens sheets 55 and 56 and is converged in a viewing area up to about 70 degrees toward the viewer. By inserting the lens sheets 55 and 56, the light reaching the viewer doubles.

The lens sheets 55 and 56 are formed by arranging minute prisms on a transparent film. The lens sheets 55 and 56 are arranged so that the prisms are arranged at right angles to each other so that the viewing angles in the X and Y directions can be increased. I make them different. In FIG. 7, the prism row of the lens sheet 56 is perpendicular to the paper surface,
Is parallel to the page.

FIG. 8 shows an example of positioning of a lens sheet in a conventional backlight unit. In the figure,
Reference numeral 59 denotes a support for supporting the lens sheets 55 and 56, and reference numeral 60 denotes a notch provided at a corner of the lens sheets 55 and 56. The notch 60 allows the lens sheet 55,
It is possible to prevent wrong assembling of the front and back of 56.

However, in this method, if two lens sheets are originally inserted, it is difficult to find even if one is forgotten. Even if two sheets are inserted, the lens sheets 55, 5
No. 6 insertion order cannot be confirmed. Furthermore, since the diffusion plate 54, the light guide plate 51, and the reflection sheet 53 are inserted on the lens sheet 56 in a stacked manner, the backlight unit 57 is completed after the backlight unit 57 is completed.
It was not possible to physically check whether the 7 mounted components were correctly attached. Therefore, conventionally, the liquid crystal panel 58 is attached, the display screen is operated, and the luminance, the viewing angle, and the like are observed to perform the unit inspection. Those with abnormal operations were dropped from the assembly line and disassembled inside for repair.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to eliminate errors in the number of lens sheets to be inserted and the number of lens sheets to be inserted in a process of assembling a backlight unit of a liquid crystal display device. It is an object of the present invention to provide a backlight unit capable of visually confirming the number and order of insertion of lens sheets even after assembly.

[0009]

SUMMARY OF THE INVENTION In order to solve this problem, the present invention provides a non-overlapping ear portion outside the angle of view of a lens sheet, and a notch for accommodating the ear in an optical component support. It is a backlight unit of the provided liquid crystal display device. The reflected light reflected from the back of the lens sheet is
It greatly differs depending on the arrangement direction of the micro prisms arranged on the surface of the lens sheet. Utilizing this phenomenon, the backlight unit of the present invention can confirm the number and order of the inserted lens sheets by observing the shape of the notch ears even after assembling the backlight unit.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first invention of the present invention provides a plurality of lens sheets having ear portions which do not overlap each other in a certain area outside the range of the angle of view and having different viewing angle characteristics. A backlight unit for a liquid crystal display device having a cutout portion corresponding to an ear portion, and the cutout portion has a support that is exposed from the back surface of the backlight unit. In the assembling process, the operator does not mistake the front and back of the lens sheet. Also, even after assembling the backlight unit,
By observing the ear of the notch, the number of inserted lens sheets can be confirmed.

A second invention of the present invention is the invention according to the first aspect, wherein the ear portions are composed of a portion overlapping with each other and a portion not overlapping with each other. The number of inserted lens sheets and the order of insertion can be confirmed.

According to a third aspect of the present invention, in the backlight unit according to the second aspect, the order of inserting the lens sheets is determined by observing the ears accommodated in the cutouts from a specific direction. This is a method of inspecting a backlight unit, which is characterized by making a determination. The number of inserted lens sheets and the insertion order of the lens sheets incorporated in the backlight unit can be confirmed by a simple visual inspection.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) FIG. 1A is a perspective view of a support for supporting components mounted on a backlight unit, and FIG.
2A is a cross-sectional view taken along line AA, FIG. 2 is a front view of a lens sheet and ears of the lens sheet, FIG. 3 is a cross-sectional view of a completed backlight unit, and FIG. 4 is a front view of a completed backlight unit. It is.

1 to 3, reference numeral 1 denotes a support for supporting a backlight unit-mounted component, 2 denotes a support shelf for supporting the backlight-mounted component, 3 denotes a cutout provided in the support 1, and 4 denotes a light source. The storage section 5, 5 is a support shelf for supporting the liquid crystal panel, 6, 7 are lens sheets, and 8, 9 are ears provided on each lens sheet.

The notch 3 is provided so as to open the upper part of the support 1, and the bottom surface is flush with the support shelf 2. The position of the notch 3 may be provided on any of the four sides of the support 1, but it is necessary to shift the notch 3 from the center point of the side.

The ears 8 and 9 are provided outside the angle of view of the lens sheet, and are provided at positions where the ears 8 and 9 are housed in the cutouts 3 when inserted into the support 1. Each of the ears 8 and 9 shown in FIG. 2 has a shape formed by overlapping portions and non-overlapping portions when overlapped.

The base material of the lens sheets 6 and 7 is, for example, t =
It is a 145 μm polyester film, on the surface of which fine prisms 10 and 11 made of acrylic resin and having a pitch of 30 to 50 μm are arranged. Prism row 1
Reference numerals 0 and 11 are provided in directions orthogonal to each other when the lens sheets 6 and 7 are overlapped. Of course, the ears 8, 9 have prism rows 10, 11 orthogonal to each other. The lens sheets 6 and 7 are attached such that the surfaces of the prism rows 10 and 11 face the liquid crystal panel and the opposite surfaces face the light source incident direction.

The lens sheets 6 and 7 concentrate the diffused light incident from the diffuser plate in the direction of the viewer by the action of a prism.
Can be doubled. The lens sheets 6 and 7 not only differ in the arrangement direction of the prisms, but are also devised so as to optimize the viewing angle, brightness, and sharpness in the X and Y axis directions by changing the material, the prism pitch, the prism angle, and the like. ing. Therefore, it is necessary to assemble the lens sheets 6 and 7 so that the front and back, the number, and the insertion order are not mistaken.

Next, a method of assembling the backlight unit will be described. First, the lens sheet 6 is stored in the support 1 with the position of the ear 8 and the position of the notch 3 aligned. At this time, since the cutout portion 3 is provided at a position other than the center point of the side of the support, the front and back of the lens sheet 6, that is, the prism forming surface will not be mistaken. It is preferable that the positioning of the lens sheet 6 be a part of the inner surface of the support 1 and the ear 8 should not be used as a reference for positioning. Next, the lens sheet 7 is stored in the same manner.

Thereafter, the diffusion plate 12,
The light guide plate 13 and the reflection sheet 14 are sequentially attached, and finally the light source 15 is attached to complete the backlight unit.
In the actual assembling process, the diffusion plate 12, the light guide plate 13,
Since the reflection sheet 14 previously integrated with the tape 16 is inserted, if the lens sheets 6 and 7 are properly attached, erroneous attachment of mounted components does not occur in subsequent steps.

FIG. 4 is a front view of the backlight unit according to the embodiment (the side opposite to the mounting surface of the liquid crystal panel).
The ears 8 and 9 stored in the notch 3 are exposed. Since the ears 8 and 9 can be seen in the figure, it can be confirmed that two sheets have been inserted, but it is difficult to confirm which is attached first. Since the lens sheets 6 and 7 are translucent, it is difficult to confirm the order of insertion simply by observing the shapes of the ears 8 and 9 and it is not practical.

FIG. 5 illustrates a method for distinguishing the arrangement direction of the prisms using the optical characteristics of the lens sheet. The figure is a view in which the surface of the lens sheet is observed by reflected light while looking at the lens sheets A and B with the prism surface facing down. A is a case where eyes are placed in the A direction parallel to the lens row, and most of the light incident on the lens sheet substrate is reflected by the prism surface and passes through the substrate again to reach the eye A. It looks so shiny. B
Is the case where the eyes are placed in the B direction orthogonal to the prism row. In this case, most of the light passes through the base film and the prism, and thus looks dark.

By utilizing the above phenomenon, the order of inserting the lens sheets 6 and 7 can be confirmed by observing the ears 8 and 9 of the cutout 3. In FIG. 4, prism row 1
When the eyes are placed in a direction parallel to 0 (indicated by C) and the ears 8 and 9 are observed with reflected light, the bright and dark portions are clearly observed. This is shown in FIG. In the embodiment, since the lens sheet 6 is first placed and the lens sheet 7 is placed thereon,
The correct order is that the concave ear 9 is above and the convex ear 8 is below it. Since only the portion where the prism array is parallel to the eye position and is exposed at the top shines, the bright portion is elongated (a) when correct, and the bright portion is wide (b) when incorrect. The pattern difference between (a) and (b) is remarkable, and erroneous insertion can be easily found.

If the eye is placed at the position D (rotated 90 degrees from C) in FIG. 4, the light and darkness are reversed, so that (a) is incorrect and (b) is the correct appearance.

In the above embodiment, the edge type backlight unit has been described. However, the present invention can be applied to backlight units of other types.

[0026]

As described above, the backlight unit according to the present invention can assemble a plurality of lens sheets without mistaken front and back, and after completing the backlight unit, the number of lens sheets,
The order of insertion can be easily confirmed by visual inspection.
Therefore, the manufacturing efficiency is improved as compared with the conventional method in which after the liquid crystal display device is completed, the liquid crystal panel is operated to detect an abnormality in mounting the mounted components.

[Brief description of the drawings]

FIG. 1A is a perspective view of a support for supporting a backlight unit mounting component according to an embodiment of the present invention. FIG. 1B is a cross-sectional view taken along line AA in FIG.

FIG. 2 is a front view of a lens sheet according to an embodiment of the present invention.

FIG. 3 is a sectional view of a completed backlight unit according to one embodiment of the present invention;

FIG. 4 is a front view of a completed backlight unit according to one embodiment of the present invention.

FIG. 5 is a diagram illustrating reflection on the back surface of a lens sheet.

FIGS. 6A and 6B are diagrams for explaining how a notch looks like an ear;

FIG. 7 is a sectional view showing the structure of a general liquid crystal display device.

FIG. 8 is a perspective view showing positioning of a conventional lens sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Support body 3 Notch part 6,7 Lens sheet 8,9 Ear 10,11 Prism arrangement

Claims (3)

(57) [Claims] A plurality of lens sheets having ear portions which do not overlap with each other in a certain region outside a view angle range and having viewing angle characteristics different from each other; and a notch portion corresponding to said ear portion. And a support in which the cutout portion is exposed from the back surface of the backlight unit. 2. The backlight unit for a liquid crystal display device according to claim 1, wherein said ear portions comprise a portion overlapping each other and a portion not overlapping. 3. The inspection of the backlight unit according to claim 2, wherein the order of inserting the lens sheets is determined by observing the ears accommodated in the cutouts from a specific direction. Method.