LED Backlighting with Reflector Cavities and Heat Sink Fins
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Solution Overview
Problem
Existing LCD display backlighting technologies, such as edge lighting with fluorescent cold cathode tubes, are inefficient, leading to significant light loss and increased thickness and power consumption, while semiconductor LEDs offer improvements but require careful placement and optical elements for uniform illumination.
Innovation Solution
A planar array of LED devices is closely spaced to the LCD devices, emitting light perpendicular to the LCD array, with reflector cavities and heat sink fins in a solid metal block to provide uniform backlighting, potentially eliminating the need for diffusing elements and reducing thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fluorescent cold cathode tubes are used for backlighting, then illumination is provided, but light loss increases significantly (up to 50% or more)
Solution Approach 1:
The patent extracts the light guiding function from the illumination system by using a separate light guide plate that directs light from edge-mounted LEDs uniformly across the display area, separating light generation from light distribution to reduce loss
Solution Approach 2:
A light guide plate is introduced as an intermediary element between the edge-mounted LEDs and the LCD panel, efficiently transferring and distributing light while minimizing loss through optimized optical paths
2Illumination intensity
If an array of fluorescent cold cathode tubes is placed behind the LCD array, then uniform illumination may be achieved, but the thickness of the LCD display increases
Solution Approach 1:
The patent transitions from a two-dimensional array of tubes behind the panel to a one-dimensional edge-mounted LED configuration with a light guide plate, changing the spatial dimension of light source placement to reduce thickness while maintaining uniformity
Solution Approach 2:
The backlighting system is segmented into separate functional components: edge-mounted LED light sources, a light guide plate for uniform distribution, and the LCD panel, allowing optimized placement that reduces overall thickness
3Illumination intensity
If an array of fluorescent cold cathode tubes is placed behind the LCD array, then illumination is provided, but power consumption increases
Solution Approach 1:
The patent changes the fundamental parameter of light source technology from fluorescent cold cathode tubes to LEDs, which have superior energy efficiency, thereby reducing power consumption while maintaining or improving illumination brightness
4Loss of energy
If LED devices are used for edge illumination, then light loss is reduced, but uniform illumination requires careful placement and optical elements
Solution Approach 1:
The patent applies local quality by positioning LEDs at specific locations along the edges and using a light guide plate with varying optical properties to achieve uniform illumination, optimizing each region's light distribution characteristics
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances optical efficiency, reduces thickness, and provides uniform illumination, improving the overall performance of LCD displays by minimizing light loss and power consumption.
Implementation Method 1
a planar array of LED devices that is closely spaced apart from the planar array of LCD devices... in operation, the planar array of LED devices provides backlighting for the planar array of LCD devices
Implementation Method 2
The first metal face includes therein an array of reflector cavities... in operation, the reflector cavity reflects light that is emitted by the at least one LED device that is mounted therein away from the reflector cavity
Implementation Method 3
The second metal face includes therein a plurality of heat sink fins
Data Source
AI summary
A display panel for a flat panel display includes a planar array of LCD devices and a planar array of LED devices that is closely spaced apart from the planar array of LCD devices, at least some of the LED devices being disposed within a periphery of the array of LCD devices such that, in operation, the planar array of LED devices provides backlighting for the planar array of LCD devices. The planar array of LED devices can include at least one solid metal block having first and second opposing metal faces. The first metal face includes therein an array of reflector cavities, and the second metal face includes therein heat sink fins that are exposed at the back face of the flat panel display.