Illumination system for an electronic device

Abstract

A light conduit to be used in conjunction with a light source in a hand-held electronic device for illuminating the keys and display of the device. The light conduit has a planar light guiding section with a plurality of light escape elements located in the keys to allow portions of the received light to escape for illuminating the keys. An light escapement section, located near the display, is extended from or optically coupled to the light guiding section to allow a further portion of the received light to escape from the light escapement section for illuminating the display. The light source can be located near the light guide section or near the light escapement section. light guide section or near the light escapement section.

Description

technical field [0001] The present invention relates generally to a lighting system for illuminating keys, buttons or display areas on a handheld electronic device, and more particularly to a system that uses total internal reflection to distribute light received from a light source to reach those keys and light guides in the display area. Background technique [0002] Handheld electronic devices such as mobile phones, personal digital assistant (PDA) devices, and communication devices have illuminated user interfaces so that users can view and use the user interfaces even when natural lighting is insufficient. One of the most common approaches is to use multiple light emitting diodes (LEDs) to independently illuminate different areas of the user interface. Using multiple LEDs for lighting results in a large drain on the power available to the electronic device. In particular, when lambertian emitting LEDs are used to illuminate user areas, only a small fraction of the ele...

AI Technical Summary

Problems solved by technology

[0003] While light guides as disclosed in Nousiainen provide an efficient method of illuminating user interfaces, making one step at a time to provide a stepped surface reduces the thickness of the light guide, thus increasing the illuminated area away from the light source. The light guide generally becomes thinner the farther

In electronic devices with many separate illuminated areas, the thickness of the light guide can become very non-uniform, so that some parts of the light guide may be too thick while other parts may be too thin

Setting up such light guides in small handheld devices can be difficult

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