Laser Backlight Light Guide Plate for Uniform Display Luminance
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Solution Overview
Problem
Edge-lit backlights using lasers as light sources suffer from luminance non-uniformity due to the high directionality of the light, leading to visible striped patterns and uneven luminance.
Innovation Solution
A backlight design incorporating a light guide plate with a sloping rear surface and a reflector, featuring line sections with curved surfaces and protruding or recessed shapes, where laser light is reflected and diffused to eliminate alignment of adjacent tips, thereby preventing luminance non-uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a laser is used as a light source in an edge-lit backlight, then the light source can be positioned away from the light-emitting area, but luminance non-uniformity and striped patterns occur due to the high directionality of the light
Solution Approach 1:
The light guide plate incorporates curved surface line sections that diffract the directional laser light into multiple directions. The curved surfaces are formed by moving straight lines around axes, creating cylindrical or conical diffraction patterns that scatter the light uniformly across the emission area, eliminating striped patterns while maintaining the benefit of remote light source positioning
Solution Approach 2:
Different regions of the light guide plate are designed with different surface properties - the front surface has curved line sections for light diffusion while the rear surface has specific slope angles for light redirection. This local differentiation ensures that the laser light is properly distributed only where needed, preventing luminance non-uniformity without affecting other areas
2Shape
If a wedge-shaped light guide plate is used to redirect light upward, then the light can be directed toward the emission area, but luminance non-uniformity still occurs due to the high directionality of laser light
Solution Approach 1:
The curved surface line sections on the front surface diffract the laser light into multiple directions, complementing the wedge-shaped rear surface that redirects light upward. This combination ensures uniform light distribution across the emission area while maintaining effective light direction control
Solution Approach 2:
The light guide plate is divided into functional regions with different surface characteristics - the rear surface with wedge-shaped slopes for light redirection and the front surface with curved line sections for light diffusion. This segmentation allows each region to perform its specific function optimally, preventing luminance non-uniformity while controlling light direction
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 design effectively eliminates striped patterns and ensures uniform luminance by diffusing laser light through curved surfaces, ensuring consistent illumination across the display area.
Implementation Method 1
the laser light incident on the first end face being reflected off the front surface, the rear surface, and the reflector
Implementation Method 2
each of the line sections having a curved surface formed by moving a straight line, parallel to an axis extending in the first direction, around the axis
Data Source
AI summary
A backlight includes a light guide plate, a laser, and a reflector. The laser light incident on the first end face is reflected off the front surface, the rear surface, and the reflector, propagates inside the light guide plate, and exits from the front surface. The front surface has line sections each in a protruding or recessed shape in a region where the laser light is reflected. The line sections extend in a first direction between the first end face and the second end face, and are adjacent in a second direction perpendicular to the first direction. Each of the line sections has a curved surface formed by moving a straight line, parallel to an axis extending in the first direction, around the axis. An adjacent pair of the line sections has respective tips in the first direction that are not aligned with each other.