Light Source Module with Dual Light Guiding Cavities for Thin Backlight
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Solution Overview
Problem
Conventional backlight modules for flat displays face challenges in achieving both reduced thickness and 2D local dimming, leading to either increased thickness or display quality issues such as honeycomb or chessboard-like bright and dark zones due to splicing edges in edge-type modules.
Innovation Solution
A light source module design featuring two layers of light guiding cavities with a reflection plate, light extraction plate, sidewall structure, light source, and diffusion plate, where the light source is positioned at an angle greater than 45 degrees, reducing total thickness and improving light emitting efficiency while minimizing noticeable junctions between lighted and non-irradiated regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a direct-type backlight module with splicing-type light guiding plates is used to reduce thickness, then the thickness is reduced, but splicing edges become visible causing honeycomb or chessboard-like bright and dark zones that deteriorate display quality
Solution Approach 1:
The light guiding plate is divided into multiple light guiding units with individual light sources, allowing independent control of each segment. This segmentation enables local dimming functionality while maintaining thin profile, as each unit can be optimized independently to avoid splicing edge visibility issues.
Solution Approach 2:
Different regions of the backlight module are assigned different luminance characteristics through local control of light guiding units. This allows dark zones to be suppressed in specific areas while maintaining overall thickness reduction, improving display quality by making splicing edges less noticeable in critical regions.
2Length of stationary object
If an edge-type backlight module is used to reduce thickness, then the thickness is reduced, but the function of 2D local dimming cannot be performed
Solution Approach 1:
The backlight module is segmented into multiple independently controllable light guiding units, each with its own light source. This segmentation transforms the edge-type module into a system capable of 2D local dimming by allowing selective activation of different regions, thereby gaining adaptability without increasing thickness.
Solution Approach 2:
The backlight module incorporates dynamically controllable light sources in each light guiding unit, enabling real-time adjustment of luminance distribution. This dynamic control provides 2D local dimming functionality while maintaining the thin profile characteristic of edge-type modules.
3Adaptability or versatility
If a direct-type backlight module is used to achieve 2D local dimming, then the contrast and power efficiency are improved, but the light-mixing distance increases resulting in significant thickness
Solution Approach 1:
The patent transitions from a conventional single-layer light guiding structure to a multi-layer stacked configuration. By arranging light guiding units in multiple layers along the thickness direction, the design achieves sufficient light mixing and uniformity without requiring excessive thickness, thus resolving the contradiction between local dimming capability and thickness.
Solution Approach 2:
Multiple light guiding units are nested in a stacked configuration, with each layer containing functional elements that contribute to light distribution. This nested arrangement maximizes the use of vertical space, achieving effective light mixing and 2D local dimming within a minimized overall thickness.
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 design achieves a reduced thickness and improved display quality by ensuring uniform light distribution and reducing the visibility of dark zones between bright regions, enhancing the overall luminance uniformity and contrast of the display.
Implementation Method 1
a reflection plate 110, a light extraction plate 120, and a sidewall structure 130 together constitute a first light guiding cavity 104
Implementation Method 2
The diffusion plate is located above the light extraction plate, and a second light guiding cavity is formed between the light extraction plate and the diffusion plate
Data Source
AI summary
A light source module includes a plurality of light emitting units, and each of the light emitting units includes a reflection plate, a light extraction plate, a sidewall structure, a light source, and a diffusion plate. The light extraction plate has a plurality of first holes, and the light extraction plate and the reflection plate are opposite to each other. The sidewall structure having a plurality of second holes is located between the reflection plate and the light extraction plate, and the reflection plate, the light extraction plate, and the sidewall structure together constitute a first light guiding cavity. The light source is located in the first light guiding cavity and adjoins the sidewall structure. The diffusion plate is located above the light extraction plate, and a second light guiding cavity is formed between the light extraction plate and the diffusion plate.