Light box

Abstract

To provide a thin light box employing a light source of strong directivity such as an LED, or a light box in which occurrence of unevenness in surface illuminance is suppressed even when the number ofLEDs is reduced by a factor of 4-9 as compared with prior art. ¢MEANS FOR SOLVING PROBLEMS! The light box (1) comprises a plurality of spot light sources (4), and a light reflector (21) having recesses (22) surrounding the spot light sources (4), respectively. The spot light sources are inserted into insertion holes (23) formed in the bottom of the containing recesses (22), respectively. When theincident angle of light exiting the spot light source (4) is 0 DEG and the spot light sources (4) are spaced apart by 350 mm, the illuminance is 15000 cd/m<2> or less and the light exiting the spotlight source (4) is reflected partially or entirely on the inner surface of the containing recesses (22) before offering illumination.

Description

technical field [0001] The present invention relates to a light box, and more particularly to an interior-illuminated light box using point light sources such as LEDs (Light Emitting Diodes), and more specifically, to an interior-illuminated light box applicable to electric signboards, interior-illuminated signs, and liquid crystal display devices. Light boxes for backlights and lighting fixtures. Background technique [0002] Conventionally, straight tube-shaped light sources such as fluorescent lamps and cold-cathode tubes have been used in interior-illuminated light boxes. However, the service life of fluorescent lamps is relatively short. For example, for a 40W ordinary straight tube fluorescent lamp, its service life is about 12,000 hours. Since the fluorescent lamps are replaced every time they are disconnected, the fluorescent lamps are replaced at the same time once a year. However, there is a problem that it is necessary to work at high places at night. [0003] I...

AI Technical Summary

Problems solved by technology

[0006] However, since the light emitted by LEDs has strong directivity, when LEDs are arranged on a planar light-reflecting surface, there is a problem in that there are bright spots on the surface of the light box where the light of the LEDs directly reaches, and dark spots where the light does not reach. parts, so that the surface illuminance of the light box is uneven

[0007] If only a concave lens or prism is added in front of the LED to diffuse the emitted light, and only a light reflection plate with a visible light diffusion reflectance of 90% or more is used together with the LED, then for a thinner light box or reduce the number of LEDs There are a large number of light boxes, and there is a problem that the surface illuminance of the light boxes cannot be prevented from being uneven

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