Edge Light Lighting Device Color Uniformity
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Solution Overview
Problem
Light exiting from the edge areas of an edge light type lighting device is tinted more in primary light colors, such as blue, due to fewer instances of wavelength conversion compared to the center area, resulting in color unevenness.
Innovation Solution
A lighting device with a light guide plate featuring a light reflecting and scattering pattern, including complementary color dots and white dots on its opposite surface, which absorbs and scatters primary light rays to reduce color unevenness by increasing the density of dots towards the edges and forming a frame pattern with complementary color dots surrounding white dots, along with a wavelength converting member to emit secondary light rays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light rays travel through the light guide plate with fewer reflections (edge areas), then the structure is simpler and light transmission is more direct, but the color uniformity deteriorates due to insufficient wavelength conversion
Solution Approach 1:
The patent applies local quality by placing complementary color dots specifically at edge areas of the light guide plate where primary light rays exit directly with fewer reflections. This localized intervention converts the color of edge-emitted light to match the center area, resolving the color uniformity issue without affecting the overall light transmission efficiency of the system
Solution Approach 2:
The patent changes the optical parameter (color/wavelength) of light rays by introducing complementary color dots that perform wavelength conversion. These dots convert primary light rays (e.g., blue) to complementary colors (e.g., yellow), thereby adjusting the color temperature and achieving uniform color output across different areas of the light guide plate
2Manufacturing precision
If complementary color dots are added to convert primary light rays, then color uniformity is improved, but the device complexity increases due to additional optical components
Solution Approach 1:
The patent merges the wavelength conversion function into the light guide plate structure itself by integrating complementary color dots directly onto the plate. This integration combines the light guiding function and the color correction function into a single component, avoiding the need for separate color correction modules and thereby reducing overall device complexity
Solution Approach 2:
The complementary color dots act as an intermediary element between the primary light source and the final output. These dots mediate the color transformation by absorbing primary light rays and emitting complementary colors, thereby achieving color uniformity without requiring complex optical systems or multiple separate components
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 color unevenness in the exiting light by ensuring that the light is less tinted in primary light colors at the edges compared to the center, resulting in a more uniform color output.
Implementation Method 1
The wavelength converting member contains phosphors that are configured to emit secondary light rays in a wavelength range different from the wavelength range when excited by the primary light rays
Implementation Method 2
The complementary color dots are formed on the opposite surface along light source non-opposed adjacent end portions and configured to absorb the primary light rays and exhibit a color that makes a complementary color pair with a reference color exhibited by the primary light rays
Implementation Method 3
The light reflecting and scattering pattern includes dots having light reflectivity and light scattering properties
Data Source
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AI summary
A lighting unite 12 according to an embodiment includes a light source 17, a light guide plate 19, and a wavelength converting member. The light source 17 is configured to emit primary light rays. The light guide plate 19 includes a light entering surface 19c through which the primary light rays enter, a light exiting surface 19a through which the primary light rays exit, and a light reflecting and scattering pattern 220. The light reflecting and scattering pattern 220 includes complementary color dots 22a formed in edge areas of the opposite surface 19b and white dots 22b formed inner than the complementary color dots 22a. The complementary color dots 22a absorb primary light rays and exhibit a color that makes a complementary color pair with a reference color exhibited by the primary light rays. The white dots 22b exhibit a white color. The wavelength converting member covers the light exiting surface 19a and passes some of the primary light rays to emit planar light.