JPH05307365A - Surface light emission device - Google Patents

Abstract

PURPOSE:To enhance the incident efficiency from tubular light sources to a light transmission plate and to attain surface light emission of high brightness by forming recessed parts having recessed surfaces corresponding to the tubular light sources on the end faces of the light transmission plate and disposing a part of the tubular light sources within the recessed parts. CONSTITUTION:An electric illumination panel formed by applying this surface light emission device is constituted by disposing the surface light emission device having the light transmission plate 3, the tubular light sources 4, lighting circuit, etc., within a rectangular frame and disposing the image plate 2 thereon. The surface light emission device is disposed with two pieces of the tubular light sources 4, 4 along the end faces on both sides of the light transmission plate 3 and the length of the tubular light sources 4 is set at about the same length of the end faces of the light transmission plate 3. The recessed parts 3e having the recessed surfaces 3d corresponding to the outer peripheral surfaces of the tubular light sources 4 are formed on the end faces on both sides of the light transmission plate 3 and the tubular light sources 4 are disposed approximately apart the specified spacing in proximity to the recessed parts 3e. Then, the light released from the tubular light sources 4 enters the inside of the light transmission plate 3 from the recessed surfaces 3d and is reflected by a reflection layer 3b on the rear surface. The light diffused by a light diffusion layer 3c is uniformly radiated from the front surface of the light transmission plate 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface light emitting device used for an illumination display panel, a backlight for a display device or the like.

[0002]

2. Description of the Related Art As a surface emitting device of this type, the surface emitting device shown in FIG.
As shown in FIG.
There is known a surface emitting device in which is arranged along the end surface 40a. As shown in FIG. 9, this surface emitting device guides the light emitted from the tubular light source 41 into the light guide plate 40 from the end surface 40a of the light guide plate 40, and the reflection layer 42 provided on the back surface emits the light to the front surface. It is configured to be reflected in a direction and emit light from the front surface of the light guide plate 40.

[0003]

However, in this type of surface emitting device, only a part of the light emitted from the tubular light source such as a fluorescent lamp is effectively used, that is, the end face 40a of the light guide plate.
The light other than the light emission angle θ of the tubular light source 41 corresponding to the above is not introduced into the light guide plate 40, and there is a problem that the brightness of the light emitting surface is insufficient particularly when the light guide plate 40 has a large area.

Further, the problem that the efficiency of light incident from the tubular light source 41 to the light guide plate is low is particularly remarkable when the thickness of the light guide plate 43 is smaller than the diameter of the tubular light source 41 as shown in FIG. , And as shown in FIG. 11, the light guide plate 44
Even if the thickness of the is larger than the diameter of the tubular light source 41,
Light other than the constant emission angle θ is totally reflected from the end surface 44a of the light guide plate, so that the efficiency of incidence of light on the light guide plate is low. Therefore, there is a problem that a high-luminance tubular light source that is expensive and consumes a large amount of power is inevitably used.

The present invention has been made in order to solve the above problems, and provides a surface emitting device capable of realizing high-luminance surface emission by improving the efficiency of incidence of light from the tubular light source to the light guide plate. The purpose is to provide.

[0006]

To this end, the surface emitting device of the present invention has a light guide plate having a reflective layer on the back surface and guiding the light incident from the end surface to the inside and emitting the light from the front surface. In a surface emitting device having a tubular light source arranged along the end face, a concave portion having a concave surface corresponding to the outer peripheral curved surface of the tubular light source is formed on the end face of the light guide plate, and at least a part of the tubular light source is in the concave portion. Or a tubular light source is disposed adjacent to the recess.

[0007]

In the surface emitting device having such a structure, when the tubular light source is turned on, the light emitted from the light source enters the light guide plate through the concave surface of the recess and is reflected by the reflecting layer on the back surface. It directly reaches the front surface and is uniformly radiated from the front surface of the light guide plate.

A recess having a concave surface corresponding to the outer peripheral curved surface of the tubular light source is formed on the end face of the light guide plate, and at least a part of the tubular light source is located in the recess or in the vicinity thereof, so that the tubular light source emits light. When the generated light enters the light guide plate, the light is efficiently incident on the light guide plate from the concave surface. Therefore, light can be made incident on the light guide plate with a high incidence efficiency, and a sufficient amount of light can be made incident on the light guide plate to cause the light emitting surface to emit light with high brightness. Therefore, it is possible to form a high-luminance light emitting surface by using an ordinary tubular light source that is relatively inexpensive and consumes less power.

[0009]

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

FIG. 1 is a perspective view of an electric decoration panel to which the surface emitting device of the present invention is applied. This illuminated panel includes a light guide plate 3, a tubular light source 4, and a frame 1 formed in a rectangular shape.
A surface emitting device having a lighting circuit and the like is provided, and an image plate 2 on which an image is printed with transparency is arranged on the upper surface thereof.

In the surface emitting device, as shown in FIG. 2, two tubular light sources 4 and 4 are arranged along the end faces on both sides of the light guide plate 3. A cylindrical discharge lamp such as a fluorescent lamp is used as the tubular light source 4, and its length is substantially the same as the length of the end surface of the light guide plate 3.

In the light guide plate 3, as shown in FIG. 3, a reflective layer 3b made of a white polyester film or the like is adhered to the rear surface of a transparent plate 3a such as a transparent acrylic resin, and a light diffusion layer 3c is formed on the front surface of the transparent plate 3a. Are formed by bonding. Light diffusion layer 3c
For this, for example, a polyester film whose surface has been roughened by matte treatment is used.

The thickness of the light guide plate 3 is formed to be substantially the same as the diameter of the tubular light source 4. Further, on both end surfaces of the light guide plate 3, recesses 3e having a recessed surface 3d corresponding to the outer peripheral curved surface of the tubular light source 4 (a part of the outer peripheral curved surface of the cylinder) are formed by cutting or the like.
The tubular light source 4 is arranged close to the concave portion 3e with a substantially constant interval.

That is, as shown in FIG. 3, the concave surface 3d at the end of the light guide plate is formed by a part of the outer peripheral curved surface of the cylinder, and the cylindrical tubular light source 4 has its outer peripheral surface and the concave surface 3d located concentrically. It is arranged so as to consist of a part of an arc, whereby the outer peripheral surface of the tubular light source 4 and the concave surface 3d are arranged at equal distances.

In the surface emitting device having such a structure, when the tubular light source 4 is turned on, the light emitted from the light source is concave 3
The light diffusing layer 3c enters the inside of the light guide plate 3 from d and is reflected by the back reflecting layer 3b or directly reaches the front light diffusing layer 3c.
The diffused light diffused by is uniformly radiated from the front surface of the light guide plate 3.

A part of the tubular light source 4 is a recess 3e at the end of the light guide plate.
Since the concave surface 3d is located inside and is disposed so as to cover a part of the tubular light source 4, when the light emitted from the tubular light source 4 enters the light guide plate 3, the concave surface 3d efficiently and efficiently from the concave surface 3d. Is injected inside. For this reason, light can be made to enter the light guide plate with high incidence efficiency, and a sufficient amount of light can be made to enter the light guide plate, and its light emitting surface can be made to emit light with high brightness.

As shown in FIG. 3, a part of the tubular light source 4 is located in the concave portions 3e on both sides of the light guide plate 3, that is, in the space connecting the upper end and the lower end of the concave surface 3d, but the entire tubular light source is You may make it enter a recessed part. In addition, as shown in FIG. 4, the concave surface 13 d of the light guide plate 13 has a small curvature,
If the volume of e is small, the tubular light source 4 does not necessarily have to enter the recess 13e, and if it is close to the recess 13e, the effect of improving the incidence efficiency can be obtained.

FIG. 5 shows another embodiment. In this example, the reflection layer 23b is adhered to the front surface near both ends of the light guide plate 23. The light diffusion layer 23 is formed on the other part of the front surface in the same manner as above.
c is adhered on the transparent plate 23a, and the reflective layer 2 is provided on the back surface thereof.
3b is bonded to the whole.

As described above, since the reflection layer 23b is adhered to both ends of the light guide plate 23, that is, the front surface near the recess 23e,
The light emitted from the tubular light source 4 and entering the light guide plate 23 from the vicinity of the end of the concave surface 23d is reflected by the reflection layer 23b on the front surface thereof and guided to the vicinity of the center of the light guide plate 23.

If the reflective layer is not attached to the front surface near the recess 23e, a large amount of light is likely to be emitted from that portion because it is close to the light source.
The light is guided inside the light guide plate, and the light emitting surface can be uniformly emitted with sufficient brightness. Note that, as shown in FIG. 5, the thickness of the light guide plate 23 may be made slightly thicker than the diameter of the tubular light source 4.

FIG. 6 and FIG. 7 show still another embodiment. In this embodiment, concave portions 33e provided on both end faces of the light guide plate 33 are provided.
Is formed not by cutting or molding but by adhering other members. That is, both ends of the transparent plate 33a (made of transparent acrylic resin), which is the base of the light guide plate 33, are cut at right angles, and the thin triangular prisms 33f made of the same transparent acrylic resin (the cross section has a substantially right angle) are cut at the upper and lower ends of the end surface. The triangular shape) is adhered by a transparent adhesive along the longitudinal direction of the end face.

Then, a reflection layer 33b similar to the above is adhered to the back surface of the transparent plate 33a, and the light diffusion layer 33 is formed on the front surface thereof.
The light guide plate 33 is configured by bonding c.

When the concave portions 33e are formed on both end surfaces of the light guide plate 33 by the adhesion of the triangular prisms 33f as described above, the concave surfaces are not the accurate curved surfaces as described above, but the incidence efficiency of the light from the tubular light source 4 is high. Light guide plate 3
The end face 3 can be processed at low cost.

In the above embodiment, the light sources are provided with the tubular light sources on both end faces of the light guide plate, but the light sources need not necessarily be disposed on both end faces of the light guide plate. A tubular light source may be arranged on the peripheral end face.

[Brief description of drawings]

FIG. 1 is a perspective view of an electric decoration panel to which the surface emitting device of the present invention is applied.

FIG. 2 is a perspective view of an embodiment of the surface emitting device.

FIG. 3 is an enlarged sectional view thereof.

FIG. 4 is a partial perspective view of another embodiment.

FIG. 5 is an enlarged cross-sectional view of still another embodiment.

FIG. 6 is a partial perspective view of another embodiment.

FIG. 7 is an enlarged cross-sectional view of still another embodiment.

FIG. 8 is a perspective view of a conventional surface emitting device.

FIG. 9 is an enlarged cross-sectional view thereof.

FIG. 10 is an enlarged cross-sectional view of another conventional device.

FIG. 11 is an enlarged cross-sectional view of another conventional device.

[Explanation of symbols]

3-light guide plate, 3b-reflection layer, 3d-concave surface, 3e-recess,
4-Tubular light source.

Claims (1)

[Claims] 1. A surface emitting device comprising a light guide plate having a reflective layer on the back surface, which guides the light incident from the end face to the inside, and emits the light from the front face, and a tubular light source arranged along the end face of the light guide plate. In the device, a concave portion having a concave surface corresponding to an outer peripheral curved surface of the tubular light source is formed on an end surface of the light guide plate, at least a part of the tubular light source is located in the concave portion, or the tubular light source is close to the concave portion. A surface-emitting device characterized by being arranged.