Backlight Device with Light Absorbers for Uniform Illumination
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Solution Overview
Problem
Existing LCD television backlights face challenges in achieving thinness while maintaining uniform light intensity and reducing power consumption, often requiring numerous expensive LEDs and complex light guide concepts.
Innovation Solution
A lighting device with a semi-transparent masking element and light absorbers or retro-reflectors is used to control or eliminate bright rings around light sources, allowing for a thin design with uniform light distribution and individually controllable light sources for improved contrast and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of the LCD backlight is reduced, then the television becomes thinner and more attractive, but the capability to illuminate the LC display with uniform light intensity deteriorates
Solution Approach 1:
The patent applies local quality by creating non-uniform light absorption characteristics at different locations. Light absorbers are strategically positioned closer to LED regions where light intensity is highest, creating localized compensation zones. This allows each region to have tailored optical properties that compensate for the inherent non-uniformity in thin backlight structures, achieving overall uniform illumination despite reduced thickness.
Solution Approach 2:
The patent changes optical parameters by introducing light absorbers with specific absorption coefficients and positioning them at optimized distances from LEDs. By adjusting the absorption strength and spatial distribution, the system transforms the light propagation characteristics to achieve uniform output from a thin structure, resolving the contradiction between thickness reduction and uniformity maintenance.
2Use of energy by moving object
If individual segment control is added to improve contrast and reduce power consumption, then the backlight can dim specific segments, but the device thickness increases
Solution Approach 1:
The patent makes the light absorbers multi-functional by designing them to simultaneously achieve uniform illumination and enable segment control. The same light absorber structure that compensates for non-uniformity also serves as the control element for individual segment dimming, eliminating the need for separate control mechanisms and maintaining thin profile while enabling both uniformity and power management.
Solution Approach 2:
The patent merges the uniformity compensation function and the segment control function into a single integrated light absorber system. By combining these functions, the design avoids adding separate thick control layers, achieving both uniform illumination and individual segment controllability within a thin overall structure.
3Adaptability or versatility
If numerous small LED's are used to limit thickness increase in segmented backlights, then individual control is possible, but the cost increases
Solution Approach 1:
The patent extracts the control function from the LED quantity requirement by introducing light absorbers as the primary control mechanism. Instead of relying on numerous individually controllable LEDs, the system uses a smaller number of LEDs combined with controllable light absorbers to achieve segment control, reducing the total component count while maintaining versatility.
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
The solution enables a thin, uniformly illuminated backlight with reduced energy consumption and the ability to form various light patterns, addressing the limitations of previous technologies by effectively managing light distribution and intensity.
Implementation Method 1
By arranging a light absorber, alternatively a retro-reflector, as defined, the brightness of the undesired bright ring can be controlled or eliminated
Implementation Method 2
By arranging a light absorber, alternatively a retro-reflector, as defined, the brightness of the undesired bright ring can be controlled or eliminated
Implementation Method 3
Some of the light which is partially diffused back into the light guide by the diffusing surface of the semi-transparent hits an area surrounding the light source
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a backlight (100) for illuminating e.g. LC displays (198) of LCD televisions. In order to enable a thin design of the backlight (100) and a high uniformity of the light emitted by the backlight (100) the invention suggest a design where transparent and diffusing masking elements (120, 121, 122) mask the individual light sources (110, 111, 112) and diffuses light back into the light guide (101). Absorbing elements (130, 131, 132) or retro-reflective elements are arranged so that they surround the light sources (110, 111, 112) in order to avoid generation of bright spots or rings around the light sources (110, 111, 112).