Backlight Unit Light Guide Plate Inclined Reflective Surface
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Solution Overview
Problem
Liquid crystal display (LCD) devices face issues with luminance uniformity due to the hot spot phenomenon caused by an increased number of point light sources in backlight units, leading to reduced display quality.
Innovation Solution
A backlight unit design incorporating a reduced number of point light sources, a light guide plate with specific side surfaces for light incidence and reflection, and a wavelength converting unit using quantum dot particles to enhance luminance uniformity, including a glass tube with a phosphor and a reflective member like a silver film to distribute light efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an increased number of point light sources are used in the backlight unit, then the illumination intensity is improved, but the hot spot phenomenon occurs causing reduced luminance uniformity
Solution Approach 1:
The patent extracts the problematic hot spot phenomenon by removing excessive point light sources and retaining only the necessary number. By taking out the excess light sources that cause hot spots, the system maintains adequate illumination intensity while achieving luminance uniformity.
Solution Approach 2:
The light guide plate serves as an intermediary between the point light sources and the display panel. It mediates the light distribution by guiding and redistributing light from the reduced number of point sources across the entire display area, preventing hot spots while maintaining uniform illumination.
2Manufacturing precision
If a reduced number of point light sources are used in the backlight unit, then the luminance uniformity is improved, but the illumination intensity may be insufficient
Solution Approach 1:
The patent transitions from point-source illumination to area-source illumination by using the light guide plate to distribute light across a two-dimensional surface. This dimensional change allows a reduced number of point sources to provide sufficient illumination intensity through distributed light delivery, achieving both uniformity and adequate brightness.
Solution Approach 2:
The light guide plate performs multiple functions: it acts as a light guide, a light distributor, and a uniformity controller. This multi-functionality enables the system to maintain adequate illumination intensity while achieving luminance uniformity with fewer point light sources.
3Illumination intensity
If more point light sources are used to ensure sufficient illumination, then the illumination intensity is improved, but the device complexity increases
Solution Approach 1:
The patent merges the functions of multiple point light sources into a single light guide plate system. Instead of having separate illumination control for each light source, the light guide plate integrates and distributes light uniformly across the display area, reducing device complexity while maintaining illumination intensity.
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 achieves improved luminance uniformity, reduces manufacturing costs, and enhances display quality by preventing hot spots and utilizing blue light emitting diodes with wavelength conversion to provide uniform illumination.
Implementation Method 1
a reflective side surface thereof which is adjacent to the light-incident side surface and reflects light within the light guide plate
Implementation Method 2
a wavelength converting unit between the light-incident side surface of the light guide plate and the point light source
Data Source
AI summary
A backlight unit includes: a point light source which generates light, a light guide plate defining upper and lower surfaces thereof opposing one another, a side surface provided in plural each connecting the upper and lower surfaces to each other; and among the plural side surfaces a light-incident side surface thereof at which the point light source is disposed and on which is incident the light generated from the point light source; and a reflective side surface thereof which is adjacent to the light-incident side surface and reflects light within the light guide plate, and which forms a first angle with respect to the light-incident side surface; and a wavelength converting unit between the light guide plate and the point light source.