Optical Lens with Annular Coating for Uniform Backlight Distribution
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Solution Overview
Problem
Existing direct-lit backlight systems require a large number of LEDs to achieve uniform light distribution, leading to increased costs due to the narrow light intensity distribution range of LEDs and the presence of 'hot spots' in light emission.
Innovation Solution
An optical lens with coating portions or structures on its bottom surface is used to refract and scatter light, ensuring uniform light distribution across a target surface, reducing the number of LEDs needed and eliminating 'hot spots' by absorbing or redirecting light effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a large number of LEDs are used to achieve uniform light distribution, then luminance uniformity is improved, but device cost increases
Solution Approach 1:
The patent segments the light distribution function by dividing the lens into different zones with distinct optical properties. The lens includes a first region with a first refractive index and a second region with a second refractive index, allowing each zone to contribute differently to light distribution and achieve uniform luminance without needing multiple LEDs
Solution Approach 2:
The patent applies local quality by giving different regions of the lens different refractive indices. The first region has a first refractive index optimized for certain light distribution characteristics, while the second region has a second refractive index for different characteristics, enabling each local area to optimize its light distribution contribution
2Quantity of substance
If the spot size of each LED is increased to reduce the number of LEDs, then device cost decreases, but light distribution uniformity deteriorates due to hot spots
Solution Approach 1:
The lens is segmented into multiple regions with different refractive indices to control light distribution. This segmentation allows the single LED's light to be redistributed uniformly across the display surface, preventing hot spots while maintaining cost-effectiveness
Solution Approach 2:
The patent changes the optical parameters of the lens by using regions with different refractive indices. This parameter variation allows precise control over light propagation paths, transforming the light distribution pattern from concentrated (hot spots) to uniform across the display surface
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 achieves a wider light distribution without 'hot spots', reducing the overall cost of direct-lit backlight devices and enhancing luminance uniformity, making it suitable for applications requiring a broader light transfer function.
Implementation Method 1
A coating portion may cover at least a portion of the mounting surface, wherein the coating portion absorbs at least a fraction of light originating from the light source and refracted from the lens
Implementation Method 2
A structure portion may cover at least a portion of the mounting surface, wherein the structure portion scatters and redirects at least a fraction of light originating from the light source and refracted from the lens
Implementation Method 3
an optical lens coupled to, and located above, the light source and the annular mounting surface... refracted from the lens
Data Source
AI summary
Optical lens and light emitting device designs achieve uniform light distribution without producing a light “hot spot”, with a benefit of reducing the number of light sources needed and overall cost for direct-lit backlight device. The optical lens includes coating portions or structures on the bottom surface thereof, and a backlight device, or other light emitting device, incorporating said lens, to produce a uniform distribution of light at a target surface. The disclosed lens and light emitting device are particularly useful when an extremely wide transfer function of backlight is needed.