JPH0915594A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: To allow a light transmission plate to be fitted to a casing without using any other members and to make the whole device thinner and light weight. CONSTITUTION: A casing 3, on the side where a wire-shaped light source 7 of the light transmission plate 6 is situated, is provided with projection 3a, and fulfills its duty to control the detaching of the light transmission plate 6. The light transmission plate 3 has a wedge shape with the first end surface 6a on the wire-shaped light source 7 side being thick and the second end surface 6b on the opposite side being thin in thickness to make the gross weight light. A recessed groove 3b having a U-letter shaped section is formed in the casing 3 so as to be fitted with the second end surface 6b. Further, both side surface of the light transmission plate 6 to be fitted with an approximately L-letter shaped notched part is provided with protruding parts 6c biased toward one side of the thickness direction of the light transmission plate 6. Rigidity as a whole is improved for inserting the light transmission plate 6 into the casing 3, and further, erroneous vertical and lateral insertion of the light transmission plate 6 at the time of assembly is prevented because the protruding part 6c of the light transmission plate 6 is biasedly installed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device used as a display body for liquid crystal televisions, personal computers and the like.

[0002]

2. Description of the Related Art In recent years, transmissive liquid crystal display devices have been widely used for display devices such as notebook personal computers and portable televisions. As a surface light source device used for these liquid crystal display devices, an edge light type backlight system in which a light guide plate is placed on the back surface of a display body and a linear light source is arranged on the end surface of the light guide plate, and a light source is provided on the back surface of the display body. There is known a direct type backlight system provided in. When comparing these two, the direct type can obtain relatively high brightness but is not suitable for thinning, and the edge light type is excellent in thinness and brightness uniformity of the light emitting surface, but is disadvantageous in high brightness. Can be said. As a backlight system of a liquid crystal display device used in a notebook personal computer or the like, an edge light type backlight system is often adopted in consideration of thinness.

The structure of a conventional liquid crystal display device will be described below with reference to the drawings. FIG. 6 is a sectional view showing a liquid crystal display device including an edge light type backlight unit. In FIG. 6, 1 is a liquid crystal panel, 2 is a light source,
A backlight unit including a light guide plate and a reflection sheet,
Reference numeral 3 is a housing that holds the backlight unit 2 in a predetermined position, 4 is a frame, and 5 is a backlight fixing plate that is fixed to the housing 3 from the back side with screws or the like to support and fix the backlight unit 2.

FIG. 7 is a partial sectional view showing the structure of a backlight unit used in a liquid crystal display device. FIG.
In the figure, 6 is a flat transparent light guide plate for transmitting light, and 7
Is a linear light source provided close to one of the four sides of the light guide plate 6, 8 is a reflector plate that collects the light emitted from the linear light source 7 at the end face of the light guide plate 6, and guides it inside. Is a reflection sheet which is arranged on the back surface of the light guide plate 6 and which returns the light emitted from the back surface of the light guide plate 6 back into the light guide plate 6 to increase the illumination light emitted from the emission surface, and 10 is the emission surface of the light guide plate 6. Is a diffusion sheet installed on the side of to distribute and evenly distribute the illumination light.

The backlight unit 2 constructed as described above is fixed to the housing 3 by a backlight fixing plate 5 by a method such as screwing. Alternatively, the light guide plate 6 may be directly screwed to the housing 3.

[0006]

However, the liquid crystal display device having such a structure requires a fixing plate for fixing the backlight unit and a means such as a screw for attaching the fixing plate to the housing. There has been a problem of hindering the miniaturization and weight reduction of the liquid crystal module.

The present invention solves the above-mentioned problems of the prior art, and provides a liquid crystal display device in which the light guide plate can be attached to the housing without using any other member, and the overall thickness and weight are reduced. The purpose is to do.

[0008]

To achieve this object, the present invention provides at least a liquid crystal display panel, a housing for holding the liquid crystal display panel, and an edge light type backlight arranged on the back surface of the liquid crystal display panel. In a liquid crystal display device including a light guide plate of a type, a housing has a substantially cross-section with a second end surface opposite to the first end surface on the side where the linear light source of the light guide plate is arranged. It is characterized in that it has a concave groove having a V-shape, and a substantially L-shaped notch that engages with a convex portion formed on each side surface of the light guide plate.

Further, the convex portions formed on both side surfaces of the light guide plate are characterized in that they are formed closer to one side than the central portion in the thickness direction of the light guide plate.

Further, the case is characterized in that it has a protrusion for preventing separation, which holds down the first end face of the light guide plate in a state where the second end face of the light guide plate is inserted into the concave groove.

The light guide plate has a thick first end surface and a second end surface.
The end surface of is formed in a thin wedge shape.

[0012]

According to the above construction, the convex portion of the light guide plate and the substantially L-shaped notch portion are engaged and slid, and the second end face of the light guide plate is inserted into the substantially U-shaped concave groove to guide the light. Attach the light plate to the housing.

Further, the convex portion on the side surface of the light guide plate is formed closer to one side than the central portion in the thickness direction to prevent erroneous mounting of the light guide plate.

Further, when the second end face of the light guide plate is inserted into the groove and mounted on the housing, the projection for pressing the first end face is elastically deformed to retract the housing or the light guide plate, and is deformed after mounting. By returning, the protrusion prevents the light guide plate from coming off.

Further, by forming the light guide plate into a wedge shape having a thick first end surface and a thin second end surface, it is possible to reduce the thickness and weight.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the structure of a liquid crystal display device according to an embodiment of the present invention. Further, the same members described in FIGS. 6 and 7 of the conventional example are denoted by the same reference numerals, and the same applies to each of the following drawings.

In FIG. 1, 1 is a liquid crystal panel, 2 is a backlight unit, 3 is a housing, 3a is a protrusion provided on the housing 3, 3b is a groove, 4 is a frame, 6 is a light guide plate, and 6a is a light guide plate. First end face 6b from which light from linear light source 7 of 6 enters
Is a second end surface of the end opposite to the first end surface 6a of the light guide plate 6, 6c is a convex portion provided on each side surface of the light guide plate, 7 is a linear light source, 8 is a reflection plate, and 9 is reflection. Sheet, 10 is a diffusion sheet, 11 is on the same plane as the liquid crystal panel 1, and the liquid crystal panel 1
A tape carrier package (hereinafter referred to as TCP) connected to electrodes provided on the outer edge of the liquid crystal panel, 12 is a liquid crystal panel driving LSI mounted on the TCP 11, and 13 is the TCP 11
Is a printed circuit board for signal supply connected to.

The backlight unit 2 in the liquid crystal display device having the above structure is installed on the back side of the liquid crystal panel 1 through the housing 3 and adopts the edge light type backlight system. Further, a transparent transparent light guide plate 6 for transmitting light, a linear light source 7 such as a cold cathode tube provided along one side of the light guide plate 6, and a light emitted from the linear light source 7 are guided. A reflector 8 is arranged on the end face of the light plate 6 and is guided to the inside. Further, a reflection sheet 9 is arranged on the back surface side of the light guide plate 6, and the light emitted from the back surface of the light guide plate 6 is returned to the inside of the light guide plate 6 again to increase the illumination light emitted to the liquid crystal panel 1 side. It has a role to Further, a diffusion sheet 10 is installed on the front surface side of the light guide plate 6 in order to make the illumination light of the backlight uniform and dispersed.

As shown in FIG. 1, the linear light source 7 of the light guide plate 6 is provided.
Protrusions 3a are provided on the housing 3 on the side where is located, and play a role of restricting the detachment of the light guide plate 6. Further, the light guide plate 6 has the first end face 6 on the side of the linear light source 7 for weight reduction.
The thickness of a is thick and the second end surface 6b on the opposite side has a thin wedge shape. A concave groove 3b having a U-shaped cross section is formed in the housing 3 so as to fit with the portion of the second end surface 6b of the light guide plate 6. Further, the convex portions 6c on the side surface of the light guide plate 6 are provided at two locations, one on each side surface, and a substantially L-shaped notch 3c provided on the side surface of the housing 3.
It is provided closer to one side than the central part in the thickness direction of the light guide plate 6 so as to be fitted with (see FIG. 2). As described above, since the structure in which the light guide plate 6 is sandwiched in the housing 3 is taken, the rigidity as a whole is improved, and the convex portion 6c on the side surface of the light guide plate 6 is closer to the central portion in the thickness direction of the light guide plate 6. Since it is installed close to one side, it is possible to prevent erroneous insertion vertically and horizontally in the assembling direction.

Next, FIG. 2 is an enlarged perspective view showing the back side by partially enlarging the shapes of the housing and the light guide plate in this embodiment. In FIG. 2, reference numeral 3c is a notch formed in a substantially L shape that fits with the convex portion 6c provided on the housing 3.
FIG. 3 is a diagram showing a method of assembling the housing and the light guide plate in this embodiment. FIG. 4 is a view showing a state where the housing and the light guide plate in this embodiment are assembled. FIG.
FIG. 3 is an enlarged perspective view showing a back side by partially enlarging an example of the shapes of the housing and the light guide plate in the present embodiment. 3d is a cutout portion and 6d is a convex portion.

The procedure for mounting the light guide plate 6 on the housing 3 of this embodiment will be described below with reference to FIGS. 2, 3 and 4. As shown in FIG. 2 in which the housing 3 and the light guide plate 6 are partially enlarged and viewed from the back side, the convex portion 6c of the light guide plate 6 is dropped from the back side into the opening of the notch 3c provided in the housing 3. At this time, as shown in FIG. 3, the light guide plate 6 is installed in the direction of arrow A.
The housing 3 is pressed against the projection 3a of the above and partially elastically deformed in the direction of the arrow B. Here, the housing 3 is formed of a thin resin material, and can be easily deformed by bending elasticity within a certain range. Further, the light guide plate 6 is also made of a resin material and can be deformed by bending elasticity relatively easily as in the case 3.

Subsequently, by sliding the light guide plate 6 in the direction of arrow C, the second end face 6b of the light guide plate 6 is moved to the housing 3.
Insert into the U-shaped concave groove 3b. At the same time, the projections 6c on both side surfaces of the light guide plate 6 are slidably fitted into the notches 3c of the housing 3, and the first end surface 6a of the light guide plate 6 completely enters the inside of the projection 3a of the housing 3 and is elastic. By returning the deformed housing 3 to the original state, the light guide plate 6 is mounted and fixed to the housing 3 as shown in FIG.

Further, the height of the protrusion 3a of the housing 3 is to control the detachment of the light guide plate 6 after the light guide plate 6 is incorporated in the housing 3 in order to reduce the deformation amount of the housing 3 during assembly. The minimum required height is sufficient, and it may be about half the thickness of the light guide plate 6.

Finally, as shown in FIG. 1, the linear light source 7,
The liquid crystal panel 1 to which the reflection plate 8 and the like are attached, and the printed board 13 and the TCP 11 are connected in advance is placed on the housing 3,
The frame 4 is attached to complete the liquid crystal display device.

In the above embodiment, the notch 3c and the protrusion 6c are provided at two positions on both sides of the housing 3 and the light guide plate 6. However, it is not always necessary to provide the notch 3c and the protrusion 6c, and the light guide plate 6 is surely provided. It may be provided as needed so as to be fixed. Further, as shown in FIG. 5, if the cutout portion 3d of the housing 3 is provided in a slit shape and the convex portion 6d of the light guide plate 6 is also provided accordingly, it is possible to perform a reliable fixing even with a slight slide amount. . Also in the above case, the number of the cutouts 3d and the projections 6d is arbitrary.

[0026]

As described above, according to the present invention,
By engaging and sliding the convex portion of the light guide plate and the substantially L-shaped notch, inserting the second end surface of the light guide plate into the substantially U-shaped concave groove, and mounting the light guide plate in the housing. Since the light guide plate is sandwiched between the housings, the rigidity as a whole can be significantly improved by incorporating the light guide plate even if the rigidity of the housing alone is low.

Further, by disposing the convex portions of the light guide plate at positions displaced in the thickness direction, erroneous insertion in the assembling direction can be prevented, and assembling efficiency and stability can be improved.

When the light guide plate is mounted on the housing, the first
By elastically deforming the projections that hold down the end faces of the housing or the light guide plate and retracting it, the light guide plate can be assembled into and removed from the housing without using a special member, simplifying the assembly and maintenance of the liquid crystal display module. It is possible to improve the sex.

Further, by forming the light guide plate into a wedge shape having a thick first end surface and a thin second end surface, the weight is further reduced.
This has the effect of achieving a reduction in thickness and cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing the back side by partially enlarging the shapes of the housing and the light guide plate in the present embodiment.

FIG. 3 is a diagram showing a method of assembling the housing and the light guide plate in this embodiment.

FIG. 4 is a diagram showing a state in which a housing and a light guide plate in this embodiment are assembled.

FIG. 5 shows the shapes of the housing and the light guide plate in the present embodiment.
It is an expansion perspective view which partially enlarged the example and illustrated the back side.

FIG. 6 is a cross-sectional view showing a liquid crystal display device including a conventional edge light type backlight unit.

FIG. 7 is a partial cross-sectional view showing a configuration of a backlight unit used in a conventional liquid crystal display device.

[Explanation of symbols]

1 ... Liquid crystal panel, 2 ... Backlight unit, 3 ...
Housing, 3a ... Protrusion, 3b ... Recessed groove, 3c, 3d ... Notch,
4 ... Frame, 6 ... Light guide plate, 6a ... 1st end surface,
6b ... 2nd end surface, 6c, 6d ... Convex part, 7 ... Linear light source, 8 ... Reflector, 9 ... Reflection sheet, 10 ... Diffusion sheet, 11 ... Tape carrier package (TCP), 12 ...
Drive LSI, 13 ... Printed board.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Watanabe 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Hiroshi Takahashi, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A liquid crystal display device comprising at least a liquid crystal display panel, a housing for holding the liquid crystal display panel, and an edge light type backlight type light guide plate arranged on the back surface of the liquid crystal display panel, The housing has a concave groove having a substantially U-shaped cross section that sandwiches a second end surface of the light guide plate opposite to the first end surface on the side where the linear light source is arranged, and both sides of the light guide plate. And a substantially L-shaped cutout portion that engages with a convex portion formed on each of the surfaces, and the convex portion of the light guide plate and the substantially L-shaped cutout portion are engaged and slid to form the second end surface. A liquid crystal display device, characterized in that the light guide plate is inserted into the substantially U-shaped groove and the light guide plate is attached to the housing. 2. The liquid crystal display according to claim 1, wherein the convex portions formed on both side surfaces of the light guide plate are formed closer to one side than the central portion in the thickness direction of the light guide plate. apparatus. 3. The housing has a detachment preventing protrusion that holds down the first end face of the light guide plate in a state where the second end face of the light guide plate is inserted into the groove, and the light guide plate is provided with the protrusion. 2. The liquid crystal display device according to claim 1, wherein, when mounted on the housing, the housing or the light guide plate is elastically deformed to retract the protrusion. 4. The liquid crystal display device according to claim 1, wherein the light guide plate is formed in a wedge shape having a thick first end surface and a thin second end surface.