Lighting Device with Spatially Varying Reflectance for Display Uniformity
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Solution Overview
Problem
Conventional liquid crystal display devices experience color unevenness due to the white diffusion layer in lighting devices, which affects the output light's luminance and color consistency.
Innovation Solution
A lighting device comprising a light transmissive plate with a higher optical reflectance than transmittance, sectioned into a light source overlapping region and a peripheral region, where the light reflecting portion has a higher distribution density in the overlapping region to reflect more light and a lower distribution in the peripheral region to allow more light to pass through, accompanied by a coloring portion that adjusts the tint of the light to match or complement the specific tint caused by the light reflecting portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a white diffusion layer is used to uniformize light luminance distribution, then luminance uniformity is improved, but color unevenness is caused in the output light
Solution Approach 1:
The patent applies local quality by using different optical properties in different regions of the light transmissive plate. The light reflecting portion has higher optical reflectance than optical transmittance, while the light transmissive portion has lower optical reflectance than optical transmittance. This spatial variation in optical properties allows the plate to simultaneously achieve luminance uniformity and color consistency by compensating for the color tint in specific regions.
Solution Approach 2:
The patent utilizes color changes by introducing a coloring portion that imparts a specific tint to compensate for the color unevenness caused by the white diffusion layer. The coloring portion is strategically positioned and designed to adjust the color temperature and tint of the transmitted light, thereby eliminating the color cast introduced by the diffusion layer while maintaining luminance uniformity.
2Ease of operation
If light reflecting portion with higher optical reflectance is used, then light distribution control is improved, but color tint in transmitted light is caused
Solution Approach 1:
The patent applies segmentation by dividing the light transmissive plate into distinct functional regions: a light reflecting portion with higher optical reflectance and a light transmissive portion with lower optical reflectance. This segmentation allows independent optimization of each region's optical properties, enabling precise control over light distribution while managing color tint through the complementary light transmissive portion.
Solution Approach 2:
The light transmissive plate acts as an intermediary element between the light source and the display panel. By incorporating both light reflecting and light transmissive portions with specific optical properties, it mediates the light path to achieve both luminance uniformity and color consistency, compensating for the color tint introduced by the light reflecting portion.
3Illumination intensity
If white diffusion layer is used to reflect light, then luminance uniformity is improved, but optical transmittance is reduced
Solution Approach 1:
The patent applies local quality by creating spatially varying optical properties in the light transmissive plate. The light reflecting portion has higher optical reflectance to redirect light paths and improve uniformity, while the light transmissive portion has lower optical reflectance (higher transmittance) to minimize energy loss in regions where direct transmission is beneficial. This local differentiation optimizes both luminance uniformity and optical efficiency.
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 minimizes color unevenness by ensuring that the output light from both regions has a consistent tint, reducing differences in luminance and color, thus enhancing display quality and convenience.
Implementation Method 1
The light reflecting portion is disposed on a plate surface of the light transmissive plate, has a higher optical reflectance than an optical transmittance, and provides at least transmitted light with a specific tint
Implementation Method 2
The coloring portion colors light travelling from the light source toward the light source overlapping region with a tint having a complementary relationship with the specific tint, or colors light travelling from the light source toward the light source peripheral region with a tint having a corresponding or similar color relationship with the specific tint
Data Source
AI summary
The lighting device includes a light source, a light transmissive plate opposed to the light source, a light reflecting portion disposed on the light transmissive plate and providing at least transmitted light with a specific tint, and a coloring portion disposed on the light source and/or the light transmissive plate. The light transmissive plate includes a light source overlapping region and a light source peripheral region. The light reflecting portion is disposed with a higher distribution density in the light source overlapping region than in the light source peripheral region. The coloring portion colors light travelling from the light source toward the light source overlapping region with a tint having a complementary relationship with the specific tint, or colors light travelling from the light source toward the light source peripheral region with a tint having a corresponding or similar color relationship with the specific tint.