Holographic Waveguide Illumination for LCD Uniformity
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Solution Overview
Problem
Liquid crystal displays face challenges in achieving improved display quality due to non-uniform illumination and high energy consumption, particularly with the use of non-directional light sources like LEDs, which result in varying light intensities across the display, leading to reduced color fidelity and contrast ratios.
Innovation Solution
A lighting device utilizing a light guide substrate with a holographic-optical decoupling substrate and a diffuser module to distribute directed light beams uniformly across the light modulator, ensuring homogeneous intensity and angular distribution, thereby reducing layer thickness and energy consumption while enhancing display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If omnidirectional light sources (LEDs) are used for direct illumination, then light can be distributed homogeneously across the display surface, but energy consumption increases and the number of light sources required increases
Solution Approach 1:
The patent replaces traditional omnidirectional LED light sources with a directional laser light source that guides light through an optical fiber substrate. This substitution transforms the illumination mechanism from broad omnidirectional emission to controlled directional guidance, reducing the number of light sources needed while maintaining homogeneous distribution through the holographic-optical output substrate.
Solution Approach 2:
The patent applies local quality by using a holographic-optical output substrate with specifically designed output areas that have varying diffraction efficiencies. This allows different regions of the substrate to extract light with different characteristics, ensuring homogeneous illumination across the entire display surface while using a single directional light source.
2Illumination intensity
If omnidirectional light sources are used for direct illumination, then light can be distributed homogeneously across the display surface, but the number of light sources required increases
Solution Approach 1:
The patent merges the functions of multiple omnidirectional LED light sources into a single directional laser light source. By combining the light generation function with the light guidance function (through the optical fiber substrate) and the light distribution function (through the holographic-optical output substrate), the system achieves homogeneous illumination with fewer light sources.
Solution Approach 2:
The patent substitutes multiple simple omnidirectional LED sources with a single complex directional laser system that includes an optical fiber substrate and holographic-optical output substrate. This substitution reduces the quantity of light sources while maintaining or improving illumination homogeneity through the integrated optical system.
3Illumination intensity
If light extraction elements are attached to the rear surface of the light guide substrate, then light can be directed forward towards the light modulator, but image quality is reduced
Solution Approach 1:
The patent replaces traditional light extraction elements (printed patterns, roughened surfaces, embossed structures) with a holographic-optical output substrate that uses volumetric holograms. This substitution provides more precise control over light extraction angles and positions, improving image quality while maintaining effective light directionality towards the light modulator.
Solution Approach 2:
The patent uses a composite structure consisting of an optical fiber substrate in optical contact with a holographic-optical output substrate. This composite system combines the light guidance capability of the optical fiber substrate with the precise light extraction capability of the holographic substrate, achieving both good light directionality and high image quality.
4Use of energy by moving object
If spectrally narrowband emitting light-generating devices are used, then energy efficiency and color fidelity increase, but device complexity increases
Solution Approach 1:
The patent makes the directional laser light source multi-functional by integrating it with the optical fiber substrate and holographic-optical output substrate. This single integrated system performs light generation, light guidance, light distribution, and spectral control functions, achieving high energy efficiency and color fidelity without proportionally increasing device complexity.
Solution Approach 2:
The patent creates a composite lighting system that combines a spectrally narrowband laser source with an optical fiber substrate and holographic-optical output substrate. This composite structure leverages the spectral purity of the laser for high energy efficiency and color fidelity while using the optical components to manage the complexity of light distribution.
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 provides a compact, energy-efficient lighting system that achieves improved color fidelity and display quality by ensuring uniform illumination of the liquid crystal display, reducing the number of light sources needed and minimizing energy consumption.
Implementation Method 1
a light guide substrate for guiding at least one directed light beam
Implementation Method 2
a holographic-optical output substrate comprising a plurality of output areas, wherein an output area is configured at least to couple out a portion of the directed light beam in the form of a plurality of partial beams
Implementation Method 3
The diffuser module is configured such that at least the outermost partial beams of two adjacent output areas abut each other before exiting the diffuser module
Data Source
Figure 1~2a
Figure 2b~3
Figure 4~5
AI summary
The invention relates to an illumination device (4) for illuminating at least one light modulator system (6) of a liquid crystal display, the device comprising at least one waveguide substrate (8) for guiding at least one targeted light beam (40) that can be coupled into the waveguide substrate (8). The waveguide substrate (8) is at least in optical contact with at least one holographic optical decoupling substrate (10) comprising a plurality of decoupling regions (12) and a decoupling region (12) is at least designed to decouple part of the targeted light beam (40) in the form of a plurality of sub-beams (42, 44) in the direction of the light modulator system (6). At least one diffuser module (14, 58) is provided, said diffuser module (14, 58) being designed in such a way that at least the outermost sub-beams (46, 48) of two neighbouring decoupling regions (12) are at least adjacent to one another before exiting the diffuser module (14, 58).