Backlight Unit With Grooved Reflector and Optical Patterns
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Solution Overview
Problem
Current display devices, particularly those used in smartphones and tablets, face challenges in achieving high light efficiency and low power consumption while maintaining image quality, especially in backlight units where light distribution is uneven, leading to hotspots and luminance inconsistencies.
Innovation Solution
A backlight unit design featuring light emitting elements with a flip chip structure, a reflector with grooves, and a transparent sheet with optical path changing patterns that diffuse light and reduce hotspots, enhancing light distribution and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional backlight units use standard light emitting elements without optical path control, then the structure is simple, but light distribution is uneven causing hotspots and luminance inconsistencies
Solution Approach 1:
The optical path control layer is segmented into multiple discrete optical elements (microlenses, prisms, or reflectors) positioned at specific locations between the light emitting elements and display panel. Each optical element independently controls the light path from its corresponding light emitting element, dividing the optical control function into multiple manageable segments that collectively achieve uniform luminance distribution.
Solution Approach 2:
The patent applies optical path control only in specific regions where needed - specifically between the light emitting elements and the display panel in the direct-type backlight unit. The optical elements are positioned to locally modify light paths only in areas requiring correction, rather than uniformly across the entire backlight structure, thereby achieving luminance uniformity without excessive complexity.
2Illumination intensity
If more light emitting elements are used to improve light coverage, then luminance uniformity improves, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent introduces an optical path control layer as an intermediary component between the existing light emitting elements and the display panel. This intermediary layer redirects and distributes light from the original light emitting elements more effectively, achieving improved light coverage and luminance uniformity without needing to add more light emitting elements, thereby avoiding increased manufacturing cost.
Solution Approach 2:
The patent modifies the optical parameters (direction, path, distribution) of light emitted by the existing light emitting elements through the optical path control layer. By changing how light travels and distributes rather than changing the number or intensity of light sources, the patent achieves better light coverage while maintaining the same light emitting element configuration and associated manufacturing costs.
3Loss of energy
If conventional reflector designs are used, then manufacturing is simple, but light extraction efficiency is low leading to energy loss
Solution Approach 1:
The patent employs optical elements with curved surfaces (such as microlenses with spherical or aspherical profiles, or prismatic structures) in the optical path control layer. These curved surfaces efficiently redirect light rays through refraction or reflection, improving light extraction and directional control compared to flat reflector surfaces, while maintaining a relatively simple layered structure that can be manufactured using standard optical fabrication techniques.
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 improves image quality and light efficiency by reducing the number of light emitting elements required, lowering manufacturing costs and ensuring consistent luminance across the display panel.
Implementation Method 1
a transparent sheet disposed on the reflector and the plurality of light emitting elements and including a plurality of optical path changing patterns disposed at positions overlapping the plurality of light emitting elements
Implementation Method 2
a reflector disposed between the plurality of light emitting elements and having a plurality of grooves each having a predetermined size on an upper surface of the reflector
Data Source
AI summary
Embodiments of the present disclosure include a backlight unit and a display device using the backlight unit comprising a plurality of light emitting elements disposed on a substrate and each having a flip chip structure. A reflector is disposed between the plurality of light emitting elements and includes a plurality of grooves each having a predetermined size on an upper surface of the reflector. A transparent sheet is disposed on the reflector and the plurality of light emitting elements and includes a plurality of optical path changing patterns disposed at positions overlapping the plurality of light emitting elements on an opposite side of a surface of the transparent sheet adjacent to the plurality of light emitting elements and each having a central region thicker than an outer region.