JPH0584938U - Surface light source - Google Patents

Abstract

(57) [Summary] [Object] To provide a display device having a high luminous flux utilization rate and a high luminous intensity by efficiently using three or more fluorescent tubes. [Configuration] At least three aperture type fluorescent tubes 3 are used as light sources arranged on the end surface 24 of the light guide 22, and the fluorescent tubes 3 are arranged in a Δ-shaped overlap.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an edge light type surface light source device of a liquid crystal display device used for a display of a portable type small personal computer.

[0002]

[Prior Art]

 Conventionally, a display device of this type is disclosed in, for example, Japanese Patent Laid-Open No. 63-309918, and as shown in FIG. Arranges the light diffusion layer 21 on the front surface and the light guide plate 2 having the light guide 22 having the reflection layer 23 formed on the back surface, and faces the light guide plate 2 by using the aperture type fluorescent tube 3 as a light source. It is equipped with a surface light source device with a structure called an edge light type that is arranged, and is designed to be as thin as possible to make it compact and lightweight, and for thin-walled display cases that open to the main body with a keyboard. It is easy to store.

The cross section of the aperture-type fluorescent tube 3 is usually formed by a glass tube 31, a fluorescent film 32, a window 33, etc., and the light flux emitted from the fluorescent film 32 is concentrated in the window 33 and emitted to the outside. Has become.

The light flux emitted from the window portion 33 is configured to enter the end face 24 of the light guide plate 2 and to be emitted as uniformly as possible from the diffusion layer 21 which is the emission plane of the light guide plate.

[0005]

[Problems to be solved by the device]

Recently, with the progress of full-color liquid crystal display devices, there has been a strong demand for higher brightness of the above-mentioned surface light source device. In a color liquid crystal display device, this is a color filter, a TFT, a polarizing plate arranged on a liquid crystal panel. This is because the total transmissivity of light passing through such as is very low at several percent or less, and the surface luminance required for the surface light source device is 6000 to 7000 Cd / m ^2, which is several times as ^{high as} that of the monochrome liquid crystal display device. Has become.

For this reason, a fluorescent tube having a high luminous flux is required to be arranged at the end portion of the light guide plate, but there is no product satisfying the demand, and two fluorescent tubes may be used in parallel.

However, as the size of the display screen becomes larger, even if two fluorescent tubes are insufficient, it has been attempted to use two or more fluorescent tubes, but the thickness of the light guide plate is 10 mm or less, and It was not effective to arrange two or more fluorescent tubes having a diameter of about 5 mm on the end face of the light guide in a plane because the utilization factor of the luminous flux was low.

[0008]

[Means for Solving the Problems]

 The present invention has been made to solve such a problem. At least three aperture type fluorescent tubes are used as a light source arranged at the end face portion of the light guide body, and these fluorescent tubes are overlapped in a triangular shape. Arranged.

Further, the end surface portion of the light guide plate was formed obliquely, and three aperture type fluorescent tubes were arranged so as to face the end surface formed obliquely.

Further, the end face portion of the light guide plate is formed so that the mold has three end faces, and three aperture type fluorescent tubes are arranged so as to face each of the three end faces.

Further, the end face portion of the light guide plate is formed obliquely to form a reflection film, and three aperture type fluorescent tubes are arranged on the opposite side of the oblique end face on which the reflection film is formed.

[0012]

【Example】

 FIG. 1 shows a first embodiment of the present invention, 1 is an LCD panel, 2 is a light guide plate, and 3 is a fluorescent tube.

The LCD panel 1 includes an upper polarizing plate 11, an upper glass 14, a liquid crystal substance 12, a lower glass 15, and a lower polarizing plate 13 in this order from the top of the display surface. The color filter is usually formed on the liquid crystal material side of the upper glass plate 14, and the TFT (thin film transistor) is formed on the liquid crystal material side of the lower glass plate 15.

The light guide plate 2 has a light diffusion layer 21 formed on the upper side and a light reflection layer 23 formed on the lower side of a light guide 22 made of acrylic or the like, and a light beam incident from the long side end face 24. A part of the light is diffusely reflected by the reflection layer and enters the LCD panel 2 via the diffusion layer 21.

In the first embodiment, the fluorescent tubes 3 are arranged close to the end surface 24, and three fluorescent tubes 3 are arranged in a triangle shape, the two tubes on the end surface side are separated by an interval D smaller than the diameter of the fluorescent tube, and the other one. Is located at the rear of this gap, and the outgoing light beam passes through this gap and enters the end face. The three fluorescent tubes 3 are surrounded by a reflector 4.

FIG. 2 shows an embodiment corresponding to claim 3, wherein the end face 24 is formed obliquely long, and three fluorescent tubes are arranged facing the lengthened end face.

FIG. 3 shows an embodiment corresponding to claim 4, in which the end face 24 is formed to have three faces on the mold, and the three fluorescent tubes 3 face each of these three faces. Are arranged.

FIG. 4 shows an embodiment corresponding to claim 5, in which the end face 24 is formed obliquely long, and the reflective layer 25 is formed on the long end face. The three fluorescent tubes 3 are arranged on the upper surface where the diffusion layer 21 is formed on the side opposite to the oblique surface, and the light flux emitted downward is reflected by the reflective layer 24 on the oblique surface and guided. Head inside the body.

[0019]

[Effect of the device]

 As described above, at least three aperture type fluorescent tubes 3 are used as the light sources arranged on the end surface 24 of the light guide 22, and the fluorescent tubes 3 are arranged so as to be overlapped in a Δ shape, so that three fluorescent tubes are arranged. It is possible to efficiently use such a fluorescent tube, to provide a display device with high luminous efficiency and high luminous intensity.

[Submission date] August 21, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

In the first embodiment, the fluorescent tubes 3 are arranged close to the end surface 24, and three fluorescent tubes 3 are arranged in a triangle shape, the two tubes on the end surface side are separated by an interval D smaller than the diameter of the fluorescent tube, and the other one. Is located at the rear of this gap, and the outgoing light beam passes through this gap and enters the end face. The three fluorescent tubes 3 are surrounded by a reflector 4. The opening end of the reflection plate 4 is fixed to the end of the light guide 22 with a screw 16. In this fixing, it is desirable that the fixing position of the reflection plate 4 be aligned with the boundary portion between the reflection curved surface and the fixing portion and the edge portion of the light guide 22. In particular, when this reflecting plate 4 is adopted, the reflecting layer of the fluorescent tube 3 can be omitted.

[Brief description of drawings]

FIG. 1 is a side view of a surface light source device according to a first embodiment.

FIG. 2 is a side view of a second embodiment of the surface light source device.

FIG. 3 is a side view of a surface light source device according to a third embodiment.

FIG. 4 is a side view of a surface light source device according to a fourth embodiment.

FIG. 5 is a side view of a conventional surface light source device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LCD panel 11 Upper polarizing plate 12 Liquid crystal substance 13 Lower polarizing plate 14 Upper glass plate 15 Lower glass plate 2 Light guide plate 21 Diffusion layer 22 Light guide 23 Reflective layer 24 End face 3 Fluorescent tube 31 Glass tube 32 Fluorescent layer 33 Window part ( Aperture) 4 Reflector

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[Procedure amendment]

[Submission date] August 21, 1992

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (5)

[Scope of utility model registration request] 1. A surface light source device in which one surface is a light transmitting surface, and a light source is arranged at one end surface portion of a light guide plate having light transmitting property, which is provided with a light reflecting means on the other surface side opposite thereto. A surface light source device characterized in that at least three aperture type fluorescent tubes are used as the light sources arranged at the end face portion, and the fluorescent tubes are arranged so as to overlap each other in a Δ shape. 2. Two of the three aperture type fluorescent tubes are arranged on the end surface of the light guide plate with a gap equal to or smaller than the tube diameter of the fluorescent tube, and the others are arranged at the rear of the gap. The surface light source device according to claim 1. 3. A surface light source device in which a light source is disposed on one end surface of a light-transmitting light guide plate having a light-transmitting surface on one side and a light-reflecting means on the other surface side facing the light-transmitting surface. A surface light source device characterized in that at least three aperture type fluorescent tubes are arranged so as to face the one end surface portion of the light guide plate obliquely formed, and the light source arranged at the end surface portion. 4. A surface light source device in which one surface is a light transmitting surface and a light source is arranged at one end surface portion of a light transmitting plate having a light transmitting means, which is provided with a light reflecting means on the other surface side opposite to the light transmitting surface. A light source to be disposed on the end face portion is provided by disposing three aperture-type fluorescent tubes facing three end faces of one end face portion of the light guide plate formed to have three end faces on the mold. A surface light source device characterized by being configured. 5. A surface light source device in which a light source is disposed on one end surface portion of a light-transmitting light guide plate having a light transmitting surface on one side and a light reflecting means on the other surface side facing the light transmitting surface. The light source arranged on the end face portion is configured by arranging at least three aperture type fluorescent tubes facing the opposite side of the one end face portion of the light guide plate formed obliquely and having a reflection film formed thereon. A surface light source device.