Flat and thin led-based luminary providing collimated light

Abstract

The present invention provides a light-emitting device (100), comprising a plurality of light emitting diodes (107) arranged spaced apart from each other on a substrate (108), is provided. The device further comprises a light guide plate (101) having a front surface (102) and an opposing back surface (103) that is provided with an array of protrusions (104) extending towards said substrate. The light guide plate is arranged such that light-emitting diodes emits light towards light receiving faces (105) of the protrusions (104). Further, collimators (110) are arranged between the light emitting diodes and the light receiving faces, to collimate the light before it enters the light guide plate. The light from the plurality of LEDs will be transmitted in to the light guide plate and will be distributed therein before exiting the light guide plate via the front side thereof. Thus, the present invention provides a light-emitting device that provides well-distributed and collimated light from a plurality of point light sources.

Description

technical field [0001] The invention relates to a light-emitting device, which includes a plurality of light-emitting diodes spaced apart from each other and a light guide plate arranged on a substrate. Background technique [0002] Especially if the lighting device is applied eg in an office or professional environment, the lighting device should fulfill several requirements. First, the light source should have a sufficiently long service life. Traditional lighting fixtures are usually based on fluorescent tubes, which have a relatively limited lifespan. In a typical office environment, the lamps themselves would need to be replaced every 6,000 hours. This equates to a replacement every two years, at added cost to the owner. [0003] Second, the light output of the luminaire should be robust against dust and other dirt. Lighting fixtures that accumulate dust are less effective because dirt blocks light. Since cleaning lighting equipment is an expensive affair, its desi...

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Problems solved by technology

[0005] However, as mentioned above, fluorescent tubes have a limited lifespan and are expensive to replace

Furthermore, in this prior art lighting fixture, the failure of a single fluorescent tube can have a serious negative impact on the light emitting ability of the lighting panel and the uniformity of the light from the lighting panel

In this way, when one of the lamp tubes is damaged, the damaged lamp tube must be replaced immediately

[0006] Furthermore, fluorescent tubes emit a constant spectrum, which limits the color variability capabilities of such lighting panels

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