JP2000214793A - Backlight structure in display device - Google Patents

Abstract

(57) [Problem] To prevent light irradiation unevenness occurring at a portion where a light guide is fixed in an edge light type display device. SOLUTION: A portion of a convex portion 8 provided for supporting the light guide 1 and continuously contacting the outer periphery of the light guide 1 has a substantially arc shape 11, and light L emitted from a lamp is substantially arc shaped. When the light hits the shape 11, the light L is prevented from leaking to the outside, and a change in the light reflection state at the protrusion 8 is not caused.

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 for illuminating a display unit such as a liquid crystal display device.

[0002]

2. Description of the Related Art A display device using a backlight is used in various display devices for the purpose of reducing the thickness and weight of the device, and is also used, for example, in the field of liquid crystal display panels.

A display device using liquid crystal has features such as low power, light weight, and space saving, which are not present in conventional displays, and its commercial power has been enhanced by progress in peripheral technology, and it has been used in various products. Liquid crystal display devices that perform matrix display are classified into an active matrix and a simple matrix in structure. Among them, an active matrix liquid crystal display device that uses a thin film transistor as a switching element for each pixel has a crosstalk. Since a clear image display can be obtained, the display of a notebook type personal computer or EW
It is used for S displays and the like, and its market is rapidly expanding. In this liquid crystal display device, an edge light type backlight is mainly used due to a demand for low power consumption or compactness.

FIG. 5 is a vertical sectional side view showing the structure of a conventional edge light type backlight, and FIG. 6 is a front cross sectional view showing the structure of the edge light type backlight. The backlight of this type utilizes a critical angle phenomenon due to a difference in light substance. Light from a lamp 2 is incident on an end face of a light guide 1 made of a transparent member made of an acrylic resin or the like, and the inside of the light guide is changed. The light is efficiently guided from the surface of the light guide 1 uniformly by the reflection pattern 3 and the reflection plate 4 arranged on the back surface of the light guide 1 to be used as a light source of the display panel 5.

Further, due to recent demands for miniaturization, the outer peripheral portion of the display panel 5 other than the display area is reduced. At that time, the light guide 1 does not function as a light source for illuminating the entire display unit unless it is larger than the display size.
The light guide 1 is designed to be almost the outer shape, and a member for supporting the light guide plate 1 is approaching the vicinity of the display unit.

As shown in FIG. 6, the conventional structure for supporting the light guide 1 of a backlight has a projection 8 projecting from a side surface in the thickness direction of the light guide 1, and the projection 8 is attached to the outer frame 6. The light guide 1 is fitted into a concave portion 9 formed in the outer periphery of a housing 7 for holding the lamp 2 and the like provided inside the light guide 1.
Is positioned in the apparatus and is prevented from moving due to external stress or the like.

[0007]

In the notebook type personal computer, a liquid crystal display device is used as a display from the viewpoint of emphasizing functionality and energy saving, and a desktop type display unit is also used. Liquid crystal display devices have come to be used as displays with low power consumption and space savings and low heat generation. At present, the screen diagonal size of the liquid crystal display devices used in these devices has been shifted from 30 cm (12.1 inches) to 35 cm (14 inches). For this reason, the backlight size used for the liquid crystal display device exceeds 30 cm diagonally.

[0008] In such a size, the light guide becomes large and heavy, and if not securely fixed, the light guide moves due to a drop impact or the like, and collides with the lamp to break the lamp. Will occur. In order to solve this, a support structure for the light guide 1 as shown in FIG. 6 is employed.

However, in this supporting structure, as shown in FIG. 7, the light L emitted from the lamp 2 exceeds the critical angle at the wall 10 of the side of the projection 8 which is continuous with the outer periphery of the light guide 1. Since the light L strikes at a large angle, the light L escapes at this portion, and the portion is darkened, and the escaped light L is reflected, causing a problem that it appears as irradiation unevenness.

This problem has not been a problem if the peripheral structure has a margin as in the prior art because it is farther from the display range. The size was very small, and the irradiation unevenness as described above could not be ignored.

An object of the present invention is to solve the above-mentioned conventional problems. Irradiation unevenness in a portion for supporting a light guide, which is caused by downsizing of an outer shape of a display device against an increase in screen size of a display device. It is an object of the present invention to provide a backlight structure of a display device, which can prevent occurrence of an image.

[0012]

In order to achieve the above object, the present invention is directed to a configuration in which light from a lamp is incident from an end face of a light guide, and the inside of the light guide is guided to illuminate a display unit. In a backlight structure in a display device in which a convex portion is provided on a part of the light guide, an outer periphery of the convex portion is formed to be continuous in a substantially arc shape with an outer periphery of the light guide. It is characterized by the following.

Further, the present invention has a configuration in which light from a lamp is made incident from an end face of the light guide to guide the inside of the light guide to irradiate a display portion, and a concave portion is provided in a part of the light guide. In the backlight structure of the display device described above, the inner periphery of the concave portion is formed so as to be continuous in a substantially arc shape with the bottom of the concave portion.

According to the above configuration, light does not escape from the projections or recesses provided in the light guide, and it is possible to prevent a decrease in display quality due to irradiation unevenness caused when the light escapes.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. Members having the same functions as those described with reference to FIGS. 5 to 7 are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a front cross-sectional view showing an edge-light type backlight structure of a liquid crystal display device for explaining a first embodiment of the present invention. The backlight structure in the first embodiment is substantially rectangular. A plurality of (four in the figure) convex portions 8 are provided on the outer periphery of the light guide 1 having a shape, and a concave portion 9 fitted to each convex portion 8 is provided on the inner periphery of the housing 7 supporting the light guide 1. ing. In the state shown in FIG. 1, since the light guide 1 is positioned by fitting to the housing 7, the light guide 1 does not shift from a predetermined position even when a drop impact or the like is applied. The number and interval of the projections 8 and the depressions 9 are appropriately set according to specifications, and are not limited to this example as long as the light guide 1 can be supported.

Further, a portion of the convex portion 8 which is continuously in contact with the outer periphery of the light guide 1 has a substantially arc shape 11. Since this substantially arcuate shape 11 is formed continuously with the outer periphery of the light guide 1, as shown in FIG. 2, when the light L emitted from the lamp 2 strikes the substantially arcuate shape 11 portion, Since the angle of incidence is very close to 0 ° at the portion near the outer periphery of the light body 1, the light L does not escape to the outside, and the angle of incidence only changes gently even if it is headed toward the tip of the projection 8. . As a result, a point at which the convex portion 8 is in contact with the outer periphery of the light guide 1 is not known, and therefore, a change in light reflection does not occur.

Here, the width of the projection 8 may be sufficient to support the light guide 1, and if the width is too large, the housing 7 at that portion is cut off, and the rigidity of the housing 7 itself is reduced. May fall, resulting in a backlight structure having low intensity.

As described above, in the first embodiment, the light guide 1 is provided with the convex portion 8 for support, and the concave portion 9 is provided in the housing 7 corresponding to the convex portion 8, so that the convex portion 8 and the concave portion are provided. 9 and the light guide 1 is fixed to the housing 7 so that the light guide plate 1
It is possible to prevent the lamp 2 from being broken due to misalignment, and to have a structure that does not generate the uneven light distribution (irradiation) unlike the related art caused by the presence of the convex portion 8.

In FIGS. 1 and 2, a plurality of convex portions 8 are shown.
In the right-hand side of the above, both sides of the light incident side and the counter-light-in side from the lamp 2 are formed into a substantially circular arc shape 11, but only the counter-light-incoming side is formed into a substantially circular arc shape 11 like the left side. Similarly, the light distribution unevenness can be prevented.

When the projection 8 is provided on the light guide 1, in this embodiment, the projection 8 is formed in a substantially circular arc in contact with the outer periphery of the light guide 1.
As shown in FIG. 7, the same effect can be obtained even if a contact angle A occurs instead of a tangent. Further, there is no problem if the substantially circular arc is not a perfect circle but a curve such as an ellipse.

FIG. 4 is a front cross-sectional view showing an edge-light type backlight structure of a liquid crystal display device for explaining a second embodiment of the present invention. The backlight structure in the second embodiment is the same as that of the first embodiment. The difference from the backlight structure of the embodiment is that a plurality of light guides (4 in FIG.
), And a projection 16 that fits into each of the recesses 15 is provided on the inner periphery of the housing 7 that supports the light guide 1.

Further, a portion of the inner periphery 15a of the concave portion 15 which is continuously in contact with the bottom side 15b of the concave portion 15 is formed into a substantially circular arc shape 11. Since the substantially circular arc shape 11 in the concave portion 15 is formed continuously with the bottom 15b of the concave portion 15, when the light L emitted from the lamp 2 hits the substantially circular arc shape 11 portion, it is close to the bottom 15b of the concave portion 15. Since the incident angle is very close to 0 ° at the portion, the light L does not escape to the outside, and the incident angle only changes gently even toward the opening side of the concave portion 15. As a result, a point where the inner circumference 15a of the concave portion 15 contacts the bottom side 15b is not known, so that a change in light reflection does not occur.

Therefore, in the second embodiment, the light guide 1
A concave portion 15 for support, and a convex portion 16 provided on the housing 7 at a position corresponding to the concave portion 15 so that the convex portion 16 and the concave portion 15 are provided.
And the light guide 1 is fixed to the housing 7 to prevent the light guide plate 1 from being shifted and the lamp 2 from being cracked. The structure does not cause such light distribution (irradiation) unevenness.

In FIG. 4, the right side of the plurality of recesses 15 has a substantially arcuate shape 11 on both sides of the light incident side from the lamp 2 and the counter light incident side. Even when only the light incident side has a substantially arc shape 11, the light distribution unevenness can be similarly prevented.

When the recess 15 is provided in the light guide 1,
In this example, the inner circumference of the concave portion 15 is a substantially circular arc contacting the bottom side. However, as described in the first embodiment, a similar effect can be obtained even if a contact angle is generated instead of a tangent as described in the first embodiment. Can be. Further, there is no problem if the substantially circular arc is not a perfect circle but a curve such as an ellipse.

In each of the above embodiments, the arrangement of the convex portions 8 or the concave portions 15 in the light guide 1 is as shown in the drawings.
It is provided on each of the upper and lower sides of the light guide 1 that is parallel to the direction of the emitted light of the lamp 2. In some cases, a similar effect can be obtained.

[0028]

As described above, according to the backlight structure of the present invention, the light guide of the display device is provided with a convex or concave portion, and the convex or concave portion is continuous with the outer periphery of the light guide. Has a substantially arc shape, it is possible to realize a display device in which light distribution unevenness caused by a convex portion or a concave portion is eliminated.

Further, the light guide can be prevented from moving due to an impact or the like by fitting the convex portion or the concave portion with the concave-convex portion provided at the corresponding portion of the supporting housing.

[Brief description of the drawings]

FIG. 1 is a front cross-sectional view showing a backlight structure of a liquid crystal display device for explaining a first embodiment of the present invention.

FIG. 2 is an explanatory view of a traveling state of light at a convex portion of the light guide according to the first embodiment of the present invention.

FIG. 3 is a diagram showing another example of the arc shape of the convex portion of the light guide according to the first embodiment of the present invention.

FIG. 4 is a front cross-sectional view showing a backlight structure of a liquid crystal display device for explaining a second embodiment of the present invention.

FIG. 5 is a side longitudinal sectional view showing a structure of a conventional edge light type backlight portion.

FIG. 6 is a front cross-sectional view showing the structure of a conventional edge light type backlight portion.

FIG. 7 is an explanatory view showing a light traveling state at a convex portion of the light guide of the backlight shown in FIGS. 5 and 6;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light guide 2 lamp 3 reflection pattern provided on light guide 4 reflection plate provided on light guide 5 display panel 6 outer frame 7 housing 8 projection of light guide 9 recess of housing 11 projection 15 arcuate shape of light guide 16 convex portion of housing

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/1335 530 G02F 1/1335 530 (72) Inventor Takafumi Kashiwagi 1006 Odakadoma, Kadoma, Osaka Matsushita Electric Within Sangyo Co., Ltd. (72) Inventor Toshiyuki Tsubota 1006 Kazuma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.F-term (reference)

Claims (8)

[Claims] 1. A structure in which light from a lamp is made incident from an end face of a light guide to guide the inside of the light guide to irradiate a display unit, wherein a projection is provided on a part of the light guide. The backlight structure in a display device according to claim 1, wherein an outer periphery of said convex portion is formed to be continuous in a substantially arc shape with an outer periphery of said light guide. 2. The backlight structure in a display device according to claim 1, wherein a shape of the outer periphery of said convex portion on the side opposite to the light incident side is substantially arc-shaped. 3. The backlight structure according to claim 1, wherein the convex portion is a support portion that fits into a concave portion formed in a light guide supporting housing. 4. The display according to claim 1, wherein the light guide has a substantially rectangular shape, and a projection is provided on at least one of four sides in the thickness direction of the light guide. Backlight structure in the device. 5. A configuration in which light from a lamp is made incident from an end face of a light guide to guide the inside of the light guide to irradiate a display unit, and a recess is provided in a part of the light guide. A backlight structure for a display device, wherein an inner periphery of the concave portion is formed to be continuous in a substantially arc shape with a bottom of the concave portion. 6. The backlight structure in a display device according to claim 5, wherein a shape of the inner periphery of the concave portion on the light incident side is substantially circular. 7. The backlight structure according to claim 5, wherein the concave portion is a support portion that fits with a convex portion formed on a light guide supporting housing. 8. The display device according to claim 5, wherein the light guide has a substantially rectangular shape, and a recess is provided on at least one of four sides in the thickness direction of the light guide. Backlight structure.