Light Guide Plate Edge Microstructures for Backlight Stray Light Control
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Solution Overview
Problem
Conventional edge-type backlight modules suffer from large-view-angle stray light due to molten deposits formed during laser processing of light guide plates, which disrupts light reflection and refraction paths, making it difficult to concentrate light-emitting viewing angles and enhance brightness.
Innovation Solution
A light guide plate with specific light-scattering microstructures having small-size edge portions that reduce stray light by controlling the height and depth of these microstructures, combined with an inverse prism sheet and reflective sheet to concentrate light-emitting viewing angles and enhance brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser processing is used to manufacture the die core of the light guide plate, then the light guide plate can be formed with light-scattering microstructures, but molten deposits are formed on the surface which destroy reflection paths and refraction paths, resulting in large-view-angle stray light
Solution Approach 1:
The patent converts the harmful molten deposits formed during laser processing into beneficial light-scattering microstructures. By controlling the laser processing parameters and using a die core with specific surface treatment, the molten deposits are transformed into controlled microstructures that scatter light effectively, eliminating the need for additional processing steps to remove defects.
Solution Approach 2:
The patent changes the physical and chemical parameters of the light guide plate material and processing conditions. By adjusting the laser power, scanning speed, and die core surface treatment parameters, the molten deposits are controlled to form the desired light-scattering microstructures with specific size distributions and surface profiles, achieving both manufacturing ease and precision.
2Illumination intensity
If additional optical films are added to concentrate light-emitting viewing angles, then the viewing angles can be concentrated, but the backlight module becomes thicker and the effect is limited
Solution Approach 1:
The patent extracts the light concentration function from separate optical films and integrates it directly into the light guide plate structure. The light-scattering microstructures are formed as an integral part of the light guide plate, eliminating the need for additional optical films and reducing the overall module thickness while maintaining effective light concentration.
Solution Approach 2:
The patent merges the light scattering function and light guide function into a single integrated structure. The light-scattering microstructures are formed directly on the light guide plate surface, combining multiple functions into one component, thereby reducing the number of layers and overall thickness of the backlight module.
3Illumination intensity
If the edge portion of light-scattering microstructures has large height or depth, then more light can be scattered, but stray light in large viewing angles increases
Solution Approach 1:
The patent applies different surface profiles and height/depth characteristics to different regions of the light-scattering microstructures. The body portion has specific dimensions while the edge portion has controlled, smaller dimensions, creating local quality variations that optimize light scattering in the desired direction while minimizing stray light generation at the edges.
Solution Approach 2:
The patent uses partial action by forming light-scattering microstructures with controlled, moderate dimensions rather than maximizing height or depth. The edge portion dimensions are deliberately kept smaller than the body portion, providing sufficient light scattering functionality while avoiding excessive action that would generate harmful stray light.
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 stray light, concentrating light-emitting viewing angles and improving brightness by directing light beams to enter at smaller angles, resulting in a more efficient backlight module with reduced thickness.
Implementation Method 1
a bottom surface, opposite to the light-emitting surface, of the light guide plate is further provided with light-scattering microstructures to uniformly reflect light beams incident to the bottom surface to the light-emitting surface
Implementation Method 2
uniformly reflect light beams incident to the bottom surface to the light-emitting surface
Implementation Method 3
The light guide plate can guide light beams generated by the light-emitting elements to be emitted from a light-emitting surface
Data Source
AI summary
A backlight module includes a light-emitting element and a light guide plate. The light guide plate includes a first surface disposed opposite to the light-emitting element, a second surface and the third surface connected to opposite sides of the first surface. The second surface is provided with a plurality of light-scattering microstructures, and each of the light-scattering microstructures is provided with a body portion and an edge portion. The edge portion surrounds the body portion, and the body portion and the edge portion protrude from or are recessed into the second surface. The edge portion has a first height for protruding from the second surface, or a first depth for being recessed into the second surface, and the first height and the first depth range from 0.2 μm to 1.4 μm.