Backlight Unit Light Guide Plate Grating Recycle
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Solution Overview
Problem
Current backlight units suffer from non-uniform luminance and inefficiency in light output, leading to suboptimal image quality, particularly in mobile devices where power consumption is a concern.
Innovation Solution
The design incorporates a light source, input and output gratings, and recuperation elements on a light guide plate to optimize light path and intensity distribution, utilizing a dichroic layer and mirror coatings to enhance light recycling and reflection, ensuring uniform and efficient light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a powerful light source is used to improve nonuniform luminance or inefficiency, then the luminance uniformity and light output efficiency are improved, but the power consumption increases
Solution Approach 1:
The patent implements a light recovery system where a recovery grating and mirror reflect light that would otherwise be lost from the fourth surface of the light guide plate back into the light guide plate. This recovered light is then utilized by the output grating to improve luminance uniformity without requiring additional power from the light source, directly resolving the contradiction between improving luminance uniformity and reducing power consumption
2Productivity
If a powerful light source is used to improve nonuniform luminance or inefficiency, then the light output efficiency is improved, but the power consumption increases
Solution Approach 1:
The light recovery system comprising the recovery grating and mirror captures light exiting through the fourth surface and redirects it back into the light guide plate. This increases the overall light output efficiency by utilizing previously wasted light, thereby improving productivity without increasing power consumption from the light source
3Volume of moving object
If the light guide plate is designed for minimal thickness, then the device size is reduced, but the light path optimization and uniformity control become more difficult
Solution Approach 1:
The patent employs gratings (input grating, output grating, and recovery grating) that operate in the optical dimension to control light propagation. These gratings create diffraction patterns that precisely control light paths within the thin light guide plate, enabling effective light path optimization and uniformity control despite the minimal thickness of the device
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
This configuration significantly improves light uniformity and efficiency, enabling high-quality image formation with reduced power consumption, as demonstrated by increased intensity and uniformity of output light compared to traditional designs.
Implementation Method 1
an input grating provided on the light guide plate adjacent to the third surface, the input grating being configured to input the light emitted by the light source into the light guide plate such that the light input is totally reflected inside of the light guide plate
Implementation Method 2
an output grating provided on one of the first surface and the second surface of the light guide plate, the output grating being configured to diffract light that is incident on the output grating from inside of the light guide plate and output the light toward an outside of the light guide plate
Implementation Method 3
a first recuperation element provided on the one of the first surface and the second surface of the light guide plate and adjacent to the fourth surface, the first recuperation element including a first recycle grating
Implementation Method 4
a second recuperation element provided on the other one of the first surface and the second surface of the light guide plate opposite to the first recuperation element in the first direction, the second recuperation element being configured to direct, to the first recuperation element, the light propagating inside the light guide plate that is incident on the second recuperation element
Data Source
AI summary
Provided is a backlight unit including a light source emitting coherent light, a light guide plate propagating the light emitted by the light source, an input grating inputting the light from the light source into the light guide plate, an output grating provided on one surface of the light guide plate and diffracting light incident from inside the light guide plate and outputting the light, in a direction toward the outside of the light guide plate, a first recuperation element provided on one surface of the light guide plate and including a first recycle grating, and a second recuperation element provided opposite to the first recuperation element and directing, to the first recuperation element, incident light that is propagating inside the light guide plate.