Curved Edge Light Guide Plate for Backlight Brightness Uniformity
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Solution Overview
Problem
Backlight devices for liquid crystal displays with curved outlines suffer from brightness unevenness due to localized increases in exiting light rays, which affect display quality.
Innovation Solution
A lighting device with a light guide plate featuring a curved edge surface and a light collecting portion non-forming section, where the light rays are totally reflected and distributed to reduce excessive light exit through specific areas, minimizing brightness unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the light guide plate has a curved outline to match the display region, then the design appearance is improved, but brightness unevenness occurs due to localized increase in exiting light rays
Solution Approach 1:
The patent applies local quality by creating a light collecting portion non-forming section at the curved opposite edge portion, where light collecting portions are intentionally omitted. This localized modification addresses the brightness unevenness specifically at the curved edge region without affecting other areas of the light guide plate, thereby maintaining the overall curved outline design while eliminating the harmful brightness concentration effect
2Use of energy by moving object
If light collecting portions are formed across the entire light exit plate surface, then light extraction efficiency is improved, but brightness unevenness is exacerbated at curved edge portions
Solution Approach 1:
The patent extracts or removes the light collecting portions from the curved opposite edge portion to create a light collecting portion non-forming section. This extraction eliminates the source of brightness unevenness at the curved edge while light collecting portions are retained in other regions to maintain overall light extraction efficiency
3Illumination intensity
If the curved edge surface is used to guide light rays, then light distribution is improved, but excessive light exit occurs at specific areas causing brightness hotspots
Solution Approach 1:
The patent converts the harmful effect of the curved edge surface causing brightness hotspots into a beneficial design feature by deliberately creating a light collecting portion non-forming section at that location. The curved edge surface continues to guide light rays effectively, but the absence of light collecting portions prevents excessive light extraction, thereby converting the potential harm into an acceptable design compromise
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 effectively reduces brightness unevenness by controlling light distribution, ensuring consistent light exit and improved display quality.
Implementation Method 1
the light rays are totally reflected by the curved edge surface having a curved plan view shape in the opposite edge portion. The totally reflected light rays are reflected by the curved edge surface at an angle of reflection according to the angle of incident on the curved edge surface
Data Source
AI summary
A backlight device 12 includes LEDs 15, a light guide plate 17 having a light entering edge surface 17a opposite the LEDs 15 and having plate surfaces one of which is alight exit plate surface 17b, and a light collecting portion 22 including unit light collecting portions 22a that extend in a normal direction of the light entering edge surface 17a on the light exit plate surface 17b and are arranged in a perpendicular direction perpendicular to the normal direction. The light guide plate 17 includes an opposite edge portion 23 that is opposite from an end portion thereof having the light entering edge surface 17a, the opposite edge portion 23 has an edge surface a part of which is a curved edge surface 24 having a curved planar shape and the opposite edge portion 23 has the light exit plate surface 17b a part of which is a light collecting portion non-forming section 25 on which no light collecting portion 22 is formed.