Light Guide Plate Recessed Microstructures for Backlight Luminance
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Solution Overview
Problem
Conventional backlight modules face challenges in achieving uniform forward luminance and are prone to bright spot defects due to electrostatic adsorption, with existing light guide plates not effectively guiding light to maximize luminance distribution.
Innovation Solution
A backlight module design incorporating a light guide plate with recessed microstructures having specific included angles and a prism sheet configuration, which directs light beams to enhance forward luminance and avoid bright spot defects by optimizing light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional light guide plates are used, then the backlight module can be manufactured, but the forward luminance is insufficient and uniformity is poor
Solution Approach 1:
The light guide plate incorporates microstructures with different geometric characteristics at different locations: first microstructures (15-27 degrees) near the light incident surface and second microstructures (50-90 degrees) near the light emitting surface. This local differentiation optimizes light extraction and distribution at each region, improving both forward luminance and uniformity simultaneously
Solution Approach 2:
The invention introduces a vertical dimension by creating recessed microstructures with specific depth ranges (first microstructures: 5-20 μm, second microstructures: 10-30 μm). This three-dimensional configuration enables controlled light extraction angles and improves luminance distribution without compromising manufacturing feasibility
2Ease of manufacture
If conventional light guide plates are used, then the backlight module can be manufactured, but bright spot defects occur due to electrostatic adsorption
Solution Approach 1:
The invention modifies geometric parameters of the microstructures (inclination angles of 15-27 degrees for first microstructures and 50-90 degrees for second microstructures, with specific depth ranges) to change the light extraction characteristics. These parameter optimizations prevent electrostatic adsorption and eliminate bright spot defects while maintaining manufacturing feasibility through standard molding processes
3Illumination intensity
If existing light guide plate microstructures are used, then light can be guided, but luminance distribution is not maximized
Solution Approach 1:
The light guide plate is segmented into multiple functional zones with different microstructure configurations: a first region near the light incident surface with first microstructures (15-27 degrees) for initial light extraction, and a second region near the light emitting surface with second microstructures (50-90 degrees) for final light distribution. This segmentation maximizes luminance distribution by optimizing light guidance at each stage
Solution Approach 2:
The invention adds vertical depth dimension to the microstructures (first microstructures: 5-20 μm, second microstructures: 10-30 μm) to create three-dimensional light extraction paths. This dimensional enhancement enables more efficient light guidance and maximizes luminance distribution across the viewing angle range
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 enhances forward luminance and uniformity of the light output while minimizing bright spot defects, providing a more efficient light distribution within a specific viewing angle range.
Implementation Method 1
a light beam provided by a light source disposed at a light incident surface of a light guide plate is transmitted in internal of the light guide plate, and an optical microstructure (for example, an etching pattern or a screen printing pattern) at bottom of the light guide plate may spoil a total reflection of the light beam
Implementation Method 2
at least one prism sheet disposed above the light emitting surface of the light guide plate
Data Source
AI summary
A backlight module includes a light guide plate (LGP), a light source, and at least one prism sheet. The LGP includes a light emitting surface, a bottom surface, a light incident surface, and a plurality of first microstructures on the bottom surface. Each of the first microstructure is a recessed structure and includes a first surface and a second surface. An included angle between the first surface and the bottom surface ranges from 15 degrees to 27 degrees. An included angle between the second surface and the bottom surface ranges from 50 degrees to 90 degrees. The light source provides a light beam, and an included angle between a light emitting direction of the light beam emitted from the light emitting surface of the LGP and a normal direction of the light emitting surface is greater than 30 degrees. The prism sheet is disposed above the light emitting surface.