Multi-Layer Light Guide Illumination for Thin Local Dimming
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Solution Overview
Problem
Existing side-lighting illumination devices with local dimming control are often bulky and lack the ability to adjust luminance levels effectively in thinner profiles.
Innovation Solution
The illumination device incorporates multiple light guide plates with scattering portions and illuminators arranged to overlap each other, allowing for local dimming control with a thinner profile by scattering light from different regions of the upper surface, enabling precise light quantity adjustment and preventing luminance reduction at boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a side-lighting illumination device is designed with local dimming control capability, then luminance adjustment precision is improved, but device thickness increases
Solution Approach 1:
The illumination device is segmented into multiple light guide plates (first light guide plate, second light guide plate, etc.), each with its own scattering portions. This segmentation allows independent control of luminance in different regions through different light guide plates, enabling high-resolution local dimming without requiring a single thick structure.
Solution Approach 2:
The patent transitions from a single-plane illumination structure to a multi-layer stacked structure where light guide plates are arranged in the thickness direction (Z-axis). By overlapping scattering portions from different light guide plates in the thickness direction, the system achieves fine luminance control resolution without increasing the planar area, effectively solving the contradiction between precision and thickness.
2Measurement precision
If multiple scattering portions are arranged in a single light guide plate for local dimming, then luminance control resolution is improved, but the light guide plate becomes thicker
Solution Approach 1:
Instead of placing all scattering portions in a single thick light guide plate, the patent divides them across multiple thinner light guide plates. Each light guide plate contains specific scattering portions (e.g., first scattering portion, second scattering portion in different regions), and their combined effect achieves high-resolution luminance control.
Solution Approach 2:
The scattering portions that would traditionally be arranged in the planar direction within a single plate are instead distributed across multiple plates in the thickness direction. This dimensional reorganization allows the system to achieve the same luminance control resolution while reducing the thickness of individual light guide plates.
3Length of moving object
If local dimming control is implemented in a thin profile device, then device compactness is improved, but luminance uniformity deteriorates
Solution Approach 1:
Different light guide plates and their scattering portions are configured to provide different local illumination characteristics. The first light guide plate with its scattering portions covers certain regions, while the second light guide plate covers other regions, with their scattering portions strategically positioned to ensure overlapping coverage and luminance uniformity across the entire display surface.
4Measurement precision
If scattering portions are positioned to overlap in the thickness direction, then local dimming resolution is improved, but alignment precision requirements increase
Solution Approach 1:
The scattering portions are segmented across multiple light guide plates with clear functional differentiation. Each light guide plate's scattering portions are designed to complement rather than precisely overlap with others, reducing the stringent alignment requirements while maintaining high local dimming resolution.
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 allows for high-resolution local dimming control with reduced thickness, improving power efficiency and contrast while maintaining alignment and luminance consistency across the illumination surface.
Implementation Method 1
a scattering portion on the lower surface of the light guide plate, the scattering portion being configured to scatter light that comes into a light guide plate through a side surface thereof
Data Source
AI summary
An illumination device includes: a first light guide plate including a first and a second scattering portions and a first region not having the first and second scattering portions arranged therein; a second light guide plate including a third and a fourth scattering portions; a first illuminator emitting light to a first side surface of the first light guide plate; a second illuminator emitting light to a second side surface opposite to the first side surface; a third illuminator emitting light to a third side surface of the second light guide plate; and a fourth illuminator emitting light to a fourth side surface opposite to the third side surface. The second light guide plate overlaps the first light guide plate as viewed from a direction of the thicknesses thereof. The third and fourth scattering portions overlap the first region as viewed from the direction of the thicknesses.