Backlight Unit Light Guide Structure for Slim, Uniform Displays
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Solution Overview
Problem
Existing liquid crystal display apparatuses face challenges in achieving a slim form factor due to the structural limitations of conventional backlight units, which hinder the development of thinner displays.
Innovation Solution
A backlight unit design featuring a light guide member with surface roughness and a light emitting device configuration that minimizes upward light emission, utilizing a substrate with blocking patterns and a matrix arrangement of light emitting devices to enhance lateral light distribution, thereby reducing the overall thickness and improving light uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional backlight unit structures are used, then light can be supplied to the liquid crystal panel, but the display apparatus cannot achieve a slim form factor due to structural limitations
Solution Approach 1:
The patent combines the light guide member and diffuser function into a single integrated component. The light guide member itself is designed with light-diffusing particles distributed throughout its volume, eliminating the need for separate diffuser sheets and reducing overall structure thickness while maintaining light uniformity.
Solution Approach 2:
The patent employs thin-film structures for the light guide member and optical layers. By using flexible, thin-film designs with controlled thicknesses, the backlight unit achieves a compact profile while maintaining structural integrity and optical performance.
2Illumination intensity
If light emitting devices emit light uniformly in all directions, then maximum light output is achieved, but light uniformity across the display panel is poor due to upward light intensity
Solution Approach 1:
The patent implements local light emission control by positioning light-emitting devices at specific locations within the light guide member and using light-extraction structures only in regions where light is needed. The upward-facing surfaces are designed without extraction structures, while the downward-facing display area incorporates light-diffusing particles and extraction features for optimal light uniformity.
Solution Approach 2:
The patent controls light emission parameters by adjusting the orientation and emission characteristics of LED devices. LEDs are positioned and oriented to emit light primarily in downward directions toward the display panel, with emission angles and intensities optimized to achieve uniform illumination across the panel surface.
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 proposed backlight unit achieves a significantly thinner profile and improved light uniformity by maximizing lateral light emission and reducing upward light intensity, allowing for a more compact display apparatus with enhanced image quality.
Implementation Method 1
the light guide member having a surface roughness on an upper surface thereof to diffuse light
Implementation Method 2
a light emitting device disposed on the substrate and including a blocking pattern to have an intensity of light emitted in an upward direction to be equal to or less than about 80% of a maximum light intensity of the light emitting device
Data Source
AI summary
A display apparatus including a display panel, a light source configured to emit light, and a light guide disposed on the light source and covering a side of the light source, the light source including a substrate, a light emitter including a light emitting stacked layer and disposed on the substrate, a light blocking layer disposed on a side surface of the light emitting stacked layer, and a reflector disposed between the substrate and the light guide, in which the light emitter has a first length direction and a second length direction, wherein orientation angles of the light emitter in the first and second length directions are different from each other, the substrate includes a first pad electrode and second pad electrode electrically connected to the light emitter, and the first and second pad electrodes are spaced apart from each other by at least 50 μm.