Light Guide Plate Complementary Color Dots for Edge-Lit Display Uniformity
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Solution Overview
Problem
Edge light type lighting devices with wavelength converting members suffer from color unevenness due to primary light rays exiting from areas linearly extending from the ends of the wavelength converting member, which are tinted with the color of the primary light rays more than other areas, leading to inconsistent light emission.
Innovation Solution
A lighting device configuration featuring a light source array, a wavelength converting member with a holding portion and a non-wavelength converting portion, and a light guide plate with a light reflecting and scattering pattern, where the wavelength converting member is disposed between the light guide plate and the light source array, and the light reflecting and scattering pattern includes complementary color dots to absorb primary light rays and reduce color unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a wavelength converting member is used to convert primary light rays to secondary light rays, then color rendering is improved, but color unevenness occurs in areas linearly extending from the ends of the wavelength converting member
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of wavelength converting members along the light guide plate. Specifically, the density or presence of wavelength converting members is varied in different regions - with fewer or no wavelength converting members at the end regions that linearly extend from the ends of the wavelength converting member, and more wavelength converting members in intermediate regions. This local variation in composition allows different parts of the light guide plate to have different optical properties, thereby compensating for the color unevenness that would otherwise occur in the end regions.
2Use of energy by moving object
If the wavelength converting member is disposed between the light source array and the light guide plate, then light conversion efficiency is improved, but primary light rays still exit from end areas causing color inconsistency
Solution Approach 1:
The patent maintains the wavelength converting member between the light source array and the light guide plate for efficient light conversion, but introduces local quality variations by controlling the distribution of wavelength converting members. The end regions of the light guide plate (those linearly extending from the ends of the wavelength converting member) have reduced or absent wavelength converting members, while intermediate regions have full distribution. This spatially selective arrangement preserves conversion efficiency in the main area while preventing color inconsistency at the ends.
Solution Approach 2:
The patent segments the light guide plate into different functional regions based on the distribution of wavelength converting members. The plate is effectively divided into end regions (with fewer or no wavelength converting members) and intermediate regions (with full wavelength converting member distribution). This segmentation allows each region to perform its specific function - the intermediate regions provide efficient light conversion while the end regions allow primary light rays to pass through with minimal conversion, thereby maintaining color consistency across the entire plate.
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 configuration effectively reduces color unevenness by ensuring that light rays exiting from sections linearly extending from the ends of the wavelength converting member are less tinted with the primary light color, resulting in more uniform light emission.
Implementation Method 1
When primary light rays emitted by the LEDs (e.g., blue light rays) are supplied to the phosphor tube, some of the light rays excite the quantum dot phosphors inside the phosphor tube and the rest of the light rays pass through the phosphor tube. When the quantum dot phosphors are excited by the primary light rays, the quantum dot phosphors emit secondary light rays with wavelengths different from the wavelength of the primary light rays (e.g., green light rays and red light rays).
Implementation Method 2
the light reflecting and scattering pattern includes complementary color dots that are disposed along a light emitting direction of the light source on a light guide plate side of the non-wavelength converting portion and configured to absorb the primary light rays
Data Source
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AI summary
A lighting unit 12 according to the present invention includes a light source array 170, a wavelength converting member 30, and a light guide plate 19. The light source array 170 includes light sources 17 configured to emit primary light rays. The wavelength converting member 30 includes a wavelength converting portion 31, a holding portion 32, and non-wavelength converting portions 34 and 35. The wavelength converting portion 31 contains phosphors configured to emit secondary light rays when excited by the primary light rays. The holing portion 32 holds the wavelength converting portion 31 therein. The non-wavelength converting portions 34 and 35 are end sections of the holding portion32 through which the primary light rays pass. The wavelength converting member 30 is disposed between the light guide plate 19 and the light source array 170. The light guide plate 19 includes a light entering surface 19c, a light exiting surface 19a, an opposite surface 19b, and a light reflecting and scattering pattern 220 that is formed on the opposite surface 19b. The light reflecting and scattering pattern 220 includes complementary color dots 22a formed in sections of the light guide plate on a non-wavelength converting portion 34 side and a non-wavelength converting portion 35 side along a light emitting direction of the light sources 17. The complementary color dots 22a absorb the primary light rays.