JP2000056303A - Illuminating unit and liquid crystal display device using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the liquid crystal display device from having a wrinkle and a slack when a resin-made film sheet abuts on a light transmission plate or a housing in high temperature or low temperature environment owing to a difference in coefficient of expansion or from having a flaw owing to a mutual rub. SOLUTION: The light emitted from a fluorescent lamp 8 is homogenized by the light transmission plate 1 to illuminate a liquid crystal panel through the resin-made film sheet 5. Here, the sheet space 11 in the housing 3 has a large clearance enough not to allow the peripheral edge part of the resin-made film sheet about in high temperature (about 85 deg.) or low temperature (about -40 deg.) environment and projection parts 3a, 3b, 3c, and 3d or recess 5a, 5b, 5c, and 5d are provided on the respective side parts of the resin-made film sheet 5 and the recess 5a, 5b, 5c, and 5d or protrusions 3a, 3b, 3c, and 3f are provided nearby the center parts of the respective sides of a sheet mounting part so as to engage in a slidable state in any temperature environment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination unit used for illumination of a transmission type liquid crystal display device and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art Conventionally, in a display device for information equipment such as a laptop or notebook type word processor or a personal computer, an image is displayed on a transmission type liquid crystal panel by utilizing features such as light weight, thinness and low power consumption. Are frequently used.

In recent years, most of the liquid crystal panels have a built-in illumination unit for illuminating the display area of the liquid crystal panel from the back. Most of the lighting units are edge light types using a light guide plate with the spread of notebook-type word processors and personal computers that emphasize portability.

FIG. 3 shows a cross section (a fluorescent lamp arrangement side) of a lighting unit of a conventional edge light type. In this edge light type lighting unit, in order to effectively use the light emitted from the fluorescent lamp 37, the light guide plate 31 is provided on the back surface of the light guide plate 31 which has been subjected to the equalization.
Reflector (or reflection sheet) 32 having the same shape as the outer shape of
A resin film sheet 34 is provided on the surface of the light guide plate 31, and the fluorescent lamp 37 disposed on the side surface of the light guide plate 31 is wrapped by the reflector 36. The above members are housings which are resin outer frames. 33 and is held together with the back cover 35.

[0005]

However, in recent liquid crystal display devices, not only a notebook type word processor and a personal computer but also a liquid crystal monitor as a substitute for a CRT has been increased in demand, so that a higher luminance and a larger screen are required. The demands are getting stronger. However, in the case of a large size of 12 inches or more, expansion and contraction due to heat of the light guide plate, housing, and resin film sheet cannot be ignored.
Due to the difference between the coefficients of expansion, the clearance of the sheet is lost in a high-temperature or low-temperature environment, and the sheet hits the light guide plate or the housing, so that wrinkles, bending, and the like are easily generated. Therefore, in particular, wrinkles, bending and the like are likely to occur, and the resin film sheet that is likely to cause display unevenness is placed in a sheet space that is not subjected to stress or pressure from others, and in the vertical, horizontal, and thickness directions. The need to provide clearance has arisen.

On the other hand, this resin film sheet is composed of a diffusion sheet, a prism sheet, a polarization separation sheet, etc., but because of the clearance provided, when a plurality of sheets are used, the sheets move within the sheet space. There has been a problem that misalignment occurs, and at that time, they rub against each other to cause scratches, which causes display unevenness.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems. The sheet position is maintained in the sheet space while providing sufficient sheet clearance, and the sheets or the sheet and the light guide plate or the frame are connected to each other. It is an object of the present invention to provide a lighting unit having a structure in which the sheet surface is not scratched by friction of the lighting unit, and a liquid crystal display device using the same.

[0008]

According to a first aspect of the present invention, there is provided a lighting unit having a light guide plate having light equalizing means for equalizing incident light for illumination. A fluorescent lamp that is disposed on at least one side surface of the light guide plate and receives light for illumination, a reflector that reflects divergent light from the fluorescent lamp toward the light guide plate, and a back surface of the light guide plate A sheet mounting portion of the frame, on which the substantially rectangular resin film sheet is mounted, comprising a reflector plate covering the light guide plate, a resin film sheet covering the surface of the light guide plate, and a frame on which the respective elements are mounted. Is sufficient so that each side of the resin film sheet does not come into contact in any of a room temperature environment (about 25 ° C.), a high temperature environment (about 85 ° C.), and a low temperature environment (about −40 ° C.). Clear run In the vicinity of the central portion of each side of the sheet mounting portion, a concave portion or a convex portion provided on each side portion of the resin film sheet may be provided under any of the above temperature environments. Also has a protrusion or a recess that engages to the extent that it can slide.

[0009] The liquid crystal display device according to claim 2 is
A liquid crystal panel and a metal frame having a perforated display area of the liquid crystal panel are provided above the lighting unit according to the first aspect.

According to the present invention, even though a sufficient clearance is provided around the sheet, there is almost no displacement between the sheets, so that wrinkling or bending occurs in the sheet due to expansion and contraction of the resin film sheet due to heat. Thus, a structure that does not cause scratches on the sheet surface can be realized.

[0011]

Embodiments of the present invention will be specifically described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a configuration of a lighting unit according to Embodiment 1 of the present invention. FIG. 1 (a) shows a cross section thereof, and FIG. 1 (b) shows a frame body. Respectively show the shapes of the housing and the film sheet.

First, the lighting unit forms a dot pattern for light equalization on the back surface side of the light guide plate 1, and places the reflection plate 2 on the surface of the light guide plate 1, and is formed larger than the light guide plate 1. The rear cover 6 and the housing 3 are attached by fixing them with screws 4. Also,
On the surface side (outgoing light side) of the light guide plate 1, a plurality of resin film sheets 5 made of a diffusion sheet, a prism sheet, a polarization separation sheet, and the like are arranged.

A fluorescent lamp 8 is arranged on the side of the light guide plate 1 in a state where the fluorescent lamp 8 is covered by a reflector 7 except for the incident light side of the light guide plate 1, and the upper part of the reflector 7 is fixed by the housing 3. It has become.

In the lighting unit according to the present embodiment,
The housing 3 includes a resin film sheet 5, a light guide plate 1,
After the reflection plates 2 are inserted in order, the fluorescent lamp 8 is mounted together with the reflector 7, and the back cover 6 is fixed to the housing 3 with screws 4. The reflector and the reflector may be directly fixed to the housing with screws or the like without using the back cover.

In the lighting unit of the present embodiment, the sheet space 11 provided in the housing 3 has a clearance of 1% or more of the sheet size with respect to the resin film sheet 5, and is provided in a room temperature environment (about 25 ° C.). ), In a high-temperature environment (about 85 ° C.) and in a low-temperature environment (about −40 ° C.), the peripheral edge of the sheet does not abut against the housing. Also, a clearance in the thickness direction is provided so that an external stress such as the light guide plate 1 is not directly applied to the resin film sheet 5.

Here, each side of the seat mounting portion of the housing 3 forming the seat space 11 is provided with a convex portion 3a, 3b, 3c, 3d near the center thereof. Each side of the film sheet 5 is provided with a concave portion 5a, 5b, 5c, 5d which is slidably engaged under any of the above-mentioned temperature environments. Specifically, the convex portions 3a, 3b, 3c, 3d of the housing and the concave portions 5a, 5b, 5c, 5d of the resin film sheet 5 are provided.
Has a clearance of 0.1 to 0.5 mm in its width.

In the first embodiment configured as described above, even if the resin-made film sheet 5 expands and contracts due to a change in temperature, the peripheral edge of the resin film sheet 5 abuts against the housing 3.
No wrinkles, deflections, etc. occur, and friction between the sheet films or between the sheet films or the sheet and the light guide plate or frame due to the occurrence of a shift in the plurality of resin film sheets due to the engagement of the four sides. Thus, no scratch is generated on the sheet surface.

In the first embodiment, the convex portion is formed on the housing side and the concave portion is formed on the film sheet side.
The reverse is also possible. Further, the shape of the convex portion and the concave portion may be any shape as long as the shape holds the sheet position. Although the number of fluorescent lamps is one, the configuration may be such that a plurality of fluorescent lamps are arranged on one side or fluorescent lamps are arranged on a plurality of sides.

(Embodiment 2) FIG. 2 shows a liquid crystal display device using the illumination unit according to Embodiment 1 described above. This liquid crystal display device has a configuration in which a liquid crystal panel 9 is placed on a housing 3, and a lighting unit and the liquid crystal panel 9 are held by a metal frame 10 in which a display range of the liquid crystal panel 9 is opened.

According to the above configuration, since a sufficient seat space is ensured, it can be used in any of a room temperature environment (about 25 ° C.), a high temperature environment (about 85 ° C.), and a low temperature environment (about −40 ° C.). Since wrinkles and bending of the sheets do not occur and the sheet position is held in the sheet space, it is possible to realize a structure that does not scratch the sheet surface due to friction between the sheets or between the sheet and the light guide plate or the frame. it can.

[0022]

As described above, according to the present invention, in order to secure a sufficient seat space, a room temperature environment (25
° C), high temperature environment (about 85 ° C), low temperature environment (-
(About 40 ° C.), no wrinkling or bending of the sheet occurs, and at the same time, the sheet is held by the frame, so that the sheet hardly moves in the sheet space of the frame, and the sheet surface is not damaged. can do.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a lighting unit according to Embodiment 1 of the present invention, and is a view taken along an arrow AA.

FIG. 2 is a cross-sectional view illustrating a configuration of a liquid crystal display device using the illumination unit according to Embodiment 1 of the present invention.

FIG. 3 is a cross-sectional view showing a configuration of a conventional lighting unit.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light guide plate 2 reflector 3 housing (frame) 3 a, 3 b, 3 c, 3 d protrusion 4 screw 5 resin film sheet 5 a, 5 b, 5 c, 5 d recess 6 back cover 7 reflector 8 fluorescent lamp 9 liquid crystal panel 10 metal frame 11 Seat space

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor ▲ Hiro Takahashi 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F term (reference) 2H089 HA40 JA10 KA15 QA06 QA11 QA12 TA15 TA16 2H091 FA07Z FA21Z FA23Z FA32Z FB02 FC01 FC14 FC29 FD06 FD15 FD22 LA02 LA04 LA05 LA09 LA11 LA12 LA13 LA18

Claims (2)

[Claims] An illumination unit for illuminating a liquid crystal panel from a back surface thereof, comprising: a light guide plate having light equalizing means for equalizing light incident for illumination; and at least one of the light guide plates. A fluorescent lamp that is disposed on a side surface and receives light for illumination, a reflector that reflects divergent light from the fluorescent lamp toward the light guide plate, a reflector that covers a back surface of the light guide plate, and the light guide plate And a frame body on which the above elements are mounted. The sheet mounting portion of the frame body on which the substantially rectangular resin film sheet is mounted is mounted in a room temperature environment (about 25 ° C.). ), High temperature environment (about 85 ° C), low temperature environment (-40
C)), a sheet space having sufficient clearance such that each side of the resin-made film sheet does not come into contact with any other part, and near the center of each side of the sheet mounting portion, An illumination unit, characterized in that a concave portion or a convex portion provided on each side of a resin film sheet has a convex portion or a concave portion which engages to such an extent that it can slide under any of the above-mentioned temperature environments. 2. A liquid crystal display device, comprising: a liquid crystal panel; and a metal frame having an opening in a display range of the liquid crystal panel, provided above the lighting unit according to claim 1.