Liquid Crystal Display Device With Vibration-Driven Diffusion Plate
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Solution Overview
Problem
Liquid crystal display devices using laser backlighting suffer from speckle noise, which degrades display performance due to the coherent nature of laser light, and existing solutions like optical low-pass filters or vibrating diffusion plates are either costly or complex.
Innovation Solution
A liquid crystal display device design that incorporates a diffusion plate supported by a vibration generation unit, such as a vibration motor or piezo film, to vibrate the diffusion plate in a direction orthogonal to its main surface, reducing speckle noise by disturbing laser light scattering without the need for additional optical filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If laser light is used as illumination light to increase color purity, then color purity is improved, but speckle noise appears and degrades display performance
Solution Approach 1:
The patent applies mechanical vibration to the diffusion plate to reduce speckle noise. The diffusion plate is vibrated in the optical path of the laser light, which changes the scattering pattern over time and reduces the visibility of speckle patterns. This directly addresses the harmful effect of speckle noise while maintaining the use of laser light for high color purity.
2Object-affected harmful factors
If an optical low-pass filter is inserted in the optical path to reduce speckle noise, then speckle noise is reduced, but device complexity and cost increase
Solution Approach 1:
Instead of inserting an optical low-pass filter that会增加 device complexity, the patent uses mechanical vibration of the diffusion plate. This approach reduces speckle noise through dynamic scattering pattern changes without adding complex optical components to the light path.
3Object-affected harmful factors
If a diffusion plate is vibrated within a plane to reduce speckle noise, then speckle noise is reduced, but alignment accuracy may deteriorate
Solution Approach 1:
The patent specifies that the diffusion plate should be vibrated in a direction orthogonal to its main surface rather than within the plane. This orthogonal vibration direction maintains better alignment accuracy while still effectively reducing speckle noise through changes in the optical path and scattering patterns.
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 approach effectively reduces speckle noise and enhances display performance while maintaining cost efficiency by eliminating the need for additional filters and ensuring accurate alignment of the diffusion plate.
Implementation Method 1
a diffusion plate that diffuses the laser light emitted from the light guide plate
Implementation Method 2
speckle noise (a spot pattern generated when light with good coherence like a laser passes through an object or is scattered by the object)
Implementation Method 3
a vibration generation unit provided in the supporting unit and that vibrates the diffusion plate
Implementation Method 4
vibrate the diffusion plate in a direction orthogonal to its main surface, reducing speckle noise by disturbing laser light scattering
Data Source
AI summary
According to one embodiment, a liquid crystal layer is provided between a first substrate and a second substrate. A switching element is provided on the first substrate. A pixel electrode is electrically connected to the switching element. A color filter is provided on a liquid crystal side of the second substrate and corresponds to the pixel electrode. A common electrode is provided on a liquid crystal side of the color filter. A light guide plate guides laser light incident on a side surface and emits the laser light from a main surface. A diffusion plate diffuses the laser light emitted from the light guide plate and applies the laser light to the first substrate. A supporting unit supports the diffusion plate. A vibration generation unit is provided in the supporting unit and vibrates the diffusion plate.