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A light source for LCD back-lit displays utilizing embedded light detectors

A light source, photodetector technology, used in light guides, optics, instruments, etc.

Inactive Publication Date: 2006-11-01
AVAGO TECH WIRELESS IP SINGAPORE PTE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As the thickness of the light box decreases, the above-mentioned problems become more serious

Method used

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  • A light source for LCD back-lit displays utilizing embedded light detectors
  • A light source for LCD back-lit displays utilizing embedded light detectors
  • A light source for LCD back-lit displays utilizing embedded light detectors

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0015] by reference figure 1 with figure 2 , the manner in which the present invention provides its advantages can be more readily understood, figure 1 with figure 2 A prior art light box arrangement for illuminating an LCD display 16 is shown. figure 1 is a top view of the light source 10, figure 2 is through figure 1 A cross-sectional view of light source 10 is shown in line 2-2. The light source 10 illuminates a light pipe 12 using an LED array 11 . The LEDs are mounted on a circuit board 13 mounted on a second board 15 that supplies power to the LEDs. The LEDs are positioned such that light exiting the top of each LED illuminates the end face 23 of the light pipe 12 through the lens 24 . Light rays entering light pipe 12 at less than the critical angle relative to surface 21 are reflected back and forth within light pipe 12 until the light rays are absorbed or scattered by particles 22 on surface 17 . Light scattered by impinging on surface 21 at an angle greate...

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PUM

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Abstract

A light source having a photodetector embedded in a light pipe is disclosed. The light pipe includes a layer of transparent material having top and bottom surfaces and first and second opposing side surfaces that intersect the top and bottom surfaces. In one embodiment, the photodetector is embedded in the layer at a location that is adjacent to the second side surface and a plurality of light emitters are positioned so as to couple light into the layer of material through the first side edge at angles less than or equal to the critical angle for the layer of material. The bottom surface can include protrusions for scattering light toward the top surface. A controller adjusts the intensity of the various light emitters in response to changes in light intensity detected by the photodetector. Light leaving the top surface of the light pipe can be used to illuminate a display.

Description

technical field [0001] The invention relates to a light source for an LCD backlight display. Background technique [0002] Liquid crystal displays (LCDs) are widely used in computers and consumer devices such as TVs. A backlit LCD is an array of pixels where each pixel acts as a shutter, allowing or blocking light from a light source located behind that pixel. Color displays are achieved by equipping pixels with color filters so that each pixel transmits or blocks light of a specific color. The intensity of light from each pixel is set by the time that pixel is in the transmissive state. [0003] Displays are typically illuminated by a white light source that provides a uniform light intensity across the entire rear of the display. Fluorescence-based illumination sources are particularly attractive because of their high light output per watt-hour of power consumption. However, such light sources require high drive voltages, which makes them less attractive for battery-op...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02F1/1335
CPCG01J1/32G02B6/0036G02B6/0061G02B6/0068
Inventor 邢淳恩郑泰明郭春源周春杰
Owner AVAGO TECH WIRELESS IP SINGAPORE PTE