JP2534634Y2 - Surface light source device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a surface light source device used for a backlight or the like of a liquid crystal display device, and relates to a surface light source device using a light guide.

[Conventional technology]

A conventional surface light source device using a light guide has a configuration as shown in FIG. That is, in FIG. 3, reference numeral 1 denotes a linear light source such as a cold-cathode tube or the like, 2 denotes a light guide made of a transparent body, and is arranged such that the incident end face 2a is located near the light source 1;
Is a reflection plate disposed on the back surface of the light guide 2, and 5 is a tube holder covering the light source 1.

In the surface light source device having such a configuration, light from the light source 1 is made incident on the incident end face 2a of the light guide 2, reflected on the front and rear surfaces thereof, and transmitted from the incident end face 2a to the opposite end face. In the meantime, some light is emitted from the surface of the light guide 2 through the diffusion plate 3 as diffused light. Diffusion light of uniform luminance emitted from the surface of the diffusion plate 3 becomes illumination light.

The surface light source device using such a light guide has a tube holder 5 so that light from the light source 1 enters the light guide 2 from the incident end face 2a as much as possible and is effectively used, and a bright light source is obtained. An aluminum or silver vapor deposition sheet is adhered to the inner surface 5a as a reflection sheet.

[Problems to be solved by the invention]

When a surface light source device using a conventional light guide as described above is used as, for example, a light source of a liquid crystal display panel, conductive parts such as a substrate on the liquid crystal display panel side are arranged near the light source 1 and the like. When the reflection sheet is provided in the tube holder as described above because a part thereof is grounded, when the light source 1 and the reflection sheet are in contact with or extremely close to each other, the high-frequency The current leaks to the external component side via the reflection sheet, and the light amount of the light source decreases, leading to a decrease in brightness. As a countermeasure against this, a design is taken in consideration of the amount of leakage of the current, and a means for flowing an extra current to the light source 1 is adopted. In other words, the light source current is set to a rated light source current suitable for actual use at the stage of the assembling work or the like. However, this method has problems such as an increase in power consumption when a large number of devices are used.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a surface light source device having a configuration capable of effectively utilizing light from a light source and having no current leakage.

[Means for solving the problem]

The surface light source device of the present invention has a linear light source, a light guide having an incident end face arranged close to the light source, a reflection surface provided on the back surface of the light guide, and an inner surface covering the light source reflected. In order to solve the above-mentioned problem, the outer peripheral portion of the light source is formed in a region at both ends in the longitudinal direction of the light source and a central region located between the two end regions. Each is provided with a non-conductive elastic member to provide a gap between the light source, the light guide, and the tube holder.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a view showing a light source (cold cathode tube) used in the embodiment. In these figures, 1 is a light source, 2 is a light guide, 3 is a diffusion plate, 4 is a reflection plate, and 5 is a tube holder, which are basically the same as the conventional example shown in FIG. Reference numeral 6 denotes an O-ring made of a non-conductive elastic member, which is fitted on the cold-cathode tube as the light source 1 at a predetermined interval as shown in FIG. When the light source 1 provided with the non-conductive O-ring 6 is disposed in the tube holder 5 in this manner, the light source 1 and the tube holder 5 do not come into contact with each other by the O-ring 6, and a certain gap is provided. This eliminates the disadvantages of the prior art. That is, since a gap is formed between the light source 1 and the tube holder 5 by the non-conductive O-ring 6, current leakage can be prevented and the width of the O-ring 6 is small.
This arrangement has almost no effect on the amount of light emitted from the light source 1 and there is no reduction in luminance. Furthermore, at the time of transportation, this O-ring 6 prevents the influence of vibration,
For example, there is also an effect of preventing the light source 1 from being damaged due to the contact between the light source 1 and the light guide 2 due to vibration.

The width of the O-ring 6 should be as narrow as possible. Also, the number of the arrangements may be appropriately determined in consideration of the length of the tube and the like, and in consideration of stable holding and the point that the light from the light source has an appropriate luminance distribution on the diffusion plate as illumination light.

Further, the O-ring 6 may be made of any non-conductive material. For example, whether or not the O-ring 6 is an elastic body is not a fundamental problem. However, an elastic material is preferable in terms of easy attachment to a light source and setting of a desired position, and also in terms of earthquake resistance.
It is more preferable that the film has transparency.

As a material of the O-ring 6, a synthetic resin, rubber, or the like can be considered.

Further, the non-conductive material provided on the surface of the light source 1 is not limited to a material such as an O-ring, and a non-conductive material having a certain height may be intermittently adhered and applied.

[Effect of the invention]

Since the lighting device of the present invention does not generate a leak current,
There is no need to use extra power consumption, there is also the effect of deriving earthquake resistance, and the effect of preventing damage to the light source is also obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a view showing a light source of the above embodiment, and FIG. 3 is a sectional view of a conventional surface light source device.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-166585 (JP, A) JP-A-1-239702 (JP, A) JP-A 62-27306 (JP, U) JP-A 63-27306 200871 (JP, U) Japanese Utility Model Hei 2-62418 (JP, U) Japanese Utility Model Showa 64-7707 (JP, U) Japanese Utility Model Utility Model Showa 59-7506 (JP, U)

Claims (3)

(57) [Scope of request for utility model registration] 1. A linear light source, a light guide arranged such that an incident end face is located near the light source, a reflecting surface provided on a back surface of the light guide, and an inner surface covering the light source being reflected. In a surface light source device comprising a tube holder which is a surface, the light source is disposed so as to form a gap between the light guide and the tube holder, and a region of both ends in the longitudinal direction of the light source and the both ends A non-conductive elastic member is provided on an outer peripheral portion of the light source in a central region located between the regions. 2. The surface light source device according to claim 1, wherein said elastic member is made of synthetic resin or rubber. 3. The surface light source device according to claim 1, wherein said elastic member is an O-ring and is fitted to said light source.