Non-Point-Symmetric Reflector for Uniform Backlighting
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Solution Overview
Problem
Conventional backlight devices in liquid crystal display devices suffer from luminance unevenness due to point-symmetric distribution of light reflecting and transmissive portions, which becomes more noticeable when the distance between the light source and diffusion plate is reduced or the plate is made thinner.
Innovation Solution
A lighting device with a reflector having a non-point-symmetric distribution of light reflecting and transmissive portions, where the area ratio of the light reflecting portions is higher in the light source overlapping region and lower in the peripheral region, and vice versa, to ensure uniform light exit and reduce luminance unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a point-symmetric dimming dot pattern is used on the diffusion plate, then the light distribution is simple and easy to control, but luminance unevenness becomes readily visually recognizable
Solution Approach 1:
The patent applies asymmetry by changing the dimming dot pattern from point-symmetric to non-point-symmetric distribution. The dimming dots are arranged with different densities in different regions: higher density in the light source overlapping region and lower density in the peripheral region. This asymmetric arrangement prevents regular light-dark patterns while maintaining uniform luminance distribution across the display surface.
Solution Approach 2:
The patent applies local quality by varying the properties of the dimming dot pattern across different regions of the diffusion plate. Specifically, the dot density and size are adjusted locally: the light source overlapping region has higher dot density to suppress direct light transmission, while the peripheral region has lower dot density to allow sufficient light transmission. This localized variation optimizes luminance uniformity for each region's specific lighting conditions.
2Length of moving object
If the distance between the light source and diffusion plate is reduced or the diffusion plate is made thinner, then the device thickness is decreased, but luminance unevenness becomes more likely to be visible
Solution Approach 1:
The patent applies local quality by varying the properties of the dimming dot pattern across different regions of the diffusion plate. Specifically, the dot density and size are adjusted locally: the light source overlapping region has higher dot density to suppress direct light transmission, while the peripheral region has lower dot density to allow sufficient light transmission. This localized variation optimizes luminance uniformity for each region's specific lighting conditions.
Solution Approach 2:
The patent applies asymmetry by changing the dimming dot pattern from point-symmetric to non-point-symmetric distribution. The dimming dots are arranged with different densities in different regions: higher density in the light source overlapping region and lower density in the peripheral region. This asymmetric arrangement prevents regular light-dark patterns while maintaining uniform luminance distribution.
3Illumination intensity
If the area ratio of light reflecting portions is increased in the light source overlapping region, then direct light transmission is suppressed, but the overall light transmission efficiency may be reduced
Solution Approach 1:
The patent applies local quality by varying the properties of the dimming dot pattern across different regions of the diffusion plate. Specifically, the dot density and size are adjusted locally: the light source overlapping region has higher dot density to suppress direct light transmission, while the peripheral region has lower dot density to allow sufficient light transmission. This localized variation optimizes luminance uniformity for each region's specific lighting conditions.
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 non-point-symmetric distribution of light reflecting and transmissive portions in the reflector results in a complex and smooth luminance distribution, making luminance unevenness less visually recognizable, even when the thickness of the backlight device is decreased.
Implementation Method 1
The light reflecting portion is configured to reflect the light rays
Implementation Method 2
The light transmissive portion is configured to transmit the light rays
Data Source
AI summary
A lighting device includes a reflector including a unit light source region, a light reflecting portion, and a light transmissive portion. The unit light source region includes a light source overlapping region and a light source peripheral region. The light reflecting portion is included in the unit light source region and has a higher area ratio in the light source overlapping region than in the light source peripheral region. The light transmissive portion is included in the unit light source region and has a higher area ratio in the light source peripheral region than in the light source overlapping region. The unit light source region includes unit regions arranged to cover a plane surface of the unit light source region and the light reflecting portion and the light transmissive portion are allocated to the unit regions to have a non-point-symmetric distribution in the unit light source region.