JPH0529442Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention relates to a plate-shaped illumination device for a backlighting device suitable for a thin-plate display device, particularly a liquid crystal display device.

(Background of the invention) Currently, liquid crystal displays are widely used as displays that can be made thinner and with low current. Another disadvantage is that the display is difficult to see in a dark room.

In the past, people relied on external lighting to overcome this drawback, but recently the method of lighting from the back of the display surface has become popular, and it uses small light sources (such as miniature bulbs and LEDs) and It was illuminated through a light guide plate.

In this method, since the light from the light source is simply guided to the irradiation surface through only the resin light guide plate, there is a large amount of light leakage from portions other than the irradiation surface, such as side surfaces. In recent years, liquid crystal displays have been applied to various devices, and with the demand for miniaturization of these devices, devices with multiple display sections have to be brought closer together to reduce the distance between each light source. If the light source is placed like this, light leakage from the side of the light guide plate of a lit light source may cause light to enter an adjacent light guide plate that is not lit, making it appear as if the light source is lit, causing misunderstandings. It was the cause of this.

In order to prevent this, conventionally, as shown in the perspective cross-sectional view of FIG. 3, a reflective sheet 26 was attached to the side surface other than the irradiated surface, or a reflective material was painted to avoid the problem.

However, in such a light leakage prevention method, the number of parts and work steps increase, and the difficulty of workability also increases. In addition, as equipment becomes more compact, the thickness and size of attached parts such as reflective materials have become issues that cannot be ignored, and in terms of design and production technology, they are inconvenient and cannot be considered effective measures. It was hot.

(Purpose of the invention) In view of the above-mentioned disadvantages, the present invention prevents light leakage to the outside from the side surfaces etc. by making the light guide plate itself prevent light from leaking to the outside, which could not be achieved conventionally by adding reflective sheets to the light guide plate. without sacrificing the same effect as
It is an object of the present invention to provide a plate-shaped lighting device that can extremely easily meet the demand for miniaturization of equipment, and also has new effects in terms of mass production, such as reducing the number of parts and shortening and reducing the work process. purpose.

(Structure of the invention) The above purpose is to provide a light source on one side of the light guide plate,
This is achieved by forming the peripheral side surface of the light guide plate with a knurling having an angle equal to or greater than the critical angle of the material constituting the light guide plate, and by providing a slope on the reflective surface facing the irradiation surface.

The details will become clear from the embodiments of the present invention described in detail below.

(Embodiment of the invention) FIG. 1 is a perspective view showing one embodiment of the invention, and FIG. 2 is a perspective sectional view showing another embodiment of the invention.

First, a first embodiment in which the present invention is applied to an LED chip will be described with reference to FIG.

Reference numeral 1 denotes a light guide plate made of a light-transmitting material such as acrylic resin.

2 is an irradiation surface, and a display board (not shown) is arranged above this.

Reference numeral 3 denotes a knurling, which has an angle and height set to have a critical angle at which light is totally reflected, and the number and spacing thereof can be changed as necessary.

Reference numeral 4 denotes a reflective surface, which has a sloped surface in order to efficiently reflect light on the irradiation surface.

5 is a light emitting part.

When a current is passed through the lead wire 5a from a power source (not shown), the light emitting section 5 starts emitting light.

When the light emitting section 5 emits light, the light emitted therefrom is diffused into the light guide plate 1 as diffused light.

The light directed toward the irradiation surface 2 is emitted to the outside almost unchanged.

The angle of the light directed toward the reflective surface 4 is changed to the irradiation surface depending on the position and angle at which it hits, and is emitted from the irradiation surface 2 to the outside.

Light directed toward the periphery of the light guide plate 1 is reflected by the knurling 3 provided around the light guide plate 1 and remains within the light guide plate 1 without being emitted to the outside.

In this embodiment, since the light guide plate 1 is made of acrylic resin, the critical angle required for total reflection of light is 45°, so the knurl 3
When setting, consider having an angle greater than this.

Of course, when using other translucent materials, the angle should be set according to the angle of view of the material.

In addition, the installation interval and number of knurlings will vary depending on the distance between the light guide plate and the light emitting part, or the size.
It can be changed as appropriate, and more efficient settings can be made.

Further, another embodiment of the present invention is shown in FIG.

The light source 15 was inserted into a hole 11a bored in the side surface of the light guide plate 11.

Further, the reflective surface 14 is subjected to a hairline surface treatment in order to further increase the reflection efficiency, and a reflective sheet 16 is attached using an adhesive 17.

This increases the brightness of the irradiation surface 12, but from the perspective of the assembly process, the reflective sheet 16 is
Needless to say, it is much easier to just attach it to the surface than the conventional example, which involves attaching it to the surrounding area.

Moreover, the reflection surface 14 that has been subjected to a hairline-like surface treatment has the effect of increasing the brightness of the irradiation surface 12 and reducing uneven illuminance.

This kind of processing on the reflective surface and pasting of the reflective sheet,
It goes without saying that the present invention can be applied to the first embodiment described above.

(Effects of the invention) As mentioned above, by implementing the invention,
There is no need to attach reflective sheets or paint reflective materials to the sides of the light guide plate, and by simply forming the light guide plate into a shape with knurling on the sides, it is possible to create a light guide that also prevents light leakage from the sides. A light plate can be provided.

Furthermore, by adopting such a shape, when arranging a plurality of plate-shaped lighting devices, it is possible to arrange the knurled surfaces of each illumination device adjacently by directly fitting and abutting each other. The uneven shape also adds a fixing effect, so
It is advantageous and extremely easy to realize a high-density arrangement in miniaturization.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing one embodiment of the present invention, Fig. 2 is a perspective sectional view showing another embodiment of the invention, and Fig. 3 is a perspective sectional view showing a conventional example. be. 1, 11, 12...Light guide plate, 2, 12, 22...
...irradiation surface, 3,13...knurling, 4,14...
... Reflective surface, 5, 15, 25 ... Light source, 16, 26
...Reflective sheet.

Claims (1)

[Scope of Claim for Utility Model Registration] A light guide plate made of a translucent material and having an irradiation surface and a reflective surface with a slope formed opposite to the irradiation surface; and on one side of the light guide plate. and a light source provided on the light guide plate, wherein the light source is provided on a surface different from the irradiation surface and the reflective surface of the light guide plate, and the light guide plate Knurling notches having an angle equal to or larger than the critical angle of the light-transmitting material constituting the light guide plate are formed on the peripheral side surface of the surface other than the surface including the surface on which the light source is provided. The reflective surface is subjected to a hairline surface treatment, a reflective sheet is provided on the back surface of the reflective surface, and an adhesive layer is provided between the reflective sheet and the light guide plate. A plate-shaped lighting device featuring: