Backlight Device Dual-Region Illumination Control
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Solution Overview
Problem
Conventional backlight devices for dual-display devices, such as mobile phones, require multiple parts and increased thickness to illuminate both main and sub-displays efficiently, leading to a bulky and costly design.
Innovation Solution
A backlight device with a light guide plate and edge light source that includes mode-selecting and power-switching mechanisms to efficiently illuminate a main lighting region and a sub-lighting region using a set of LEDs, where the whole light source is used for the main region and a part of the source for the sub-region, along with diffusion and isotropic prism sheets for improved light control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If separate backlights are provided for main display and sub-display, then illumination efficiency for both displays is improved, but device thickness and part quantity increase
Solution Approach 1:
The patent applies multi-functionality by enabling a single backlight unit to serve dual purposes: illuminating both the main display and sub-display. The light guide plate is designed with specific optical structures that allow light to be directed to different display regions, making one backlight component perform the function of what would traditionally require two separate backlight assemblies.
Solution Approach 2:
The patent merges the illumination functions for the main display and sub-display into a single integrated backlight system. By combining the light guide plate, edge light, and control circuitry into one unit that serves both displays, the design reduces part quantity while maintaining illumination efficiency for both display regions.
2Illumination intensity
If separate backlights are provided for main display and sub-display, then illumination efficiency for both displays is improved, but device thickness increases
Solution Approach 1:
The single backlight unit is designed with multi-functional capability to illuminate both display types simultaneously, eliminating the need for stacked or adjacent separate backlight assemblies that would increase device thickness.
Solution Approach 2:
The patent utilizes the thickness dimension of the light guide plate to differentiate light paths toward the main display and sub-display. By controlling light propagation in the thickness direction through optical structures, the system achieves dual illumination without requiring additional thickness for separate backlight units.
3Device complexity
If a single backlight is used for both displays, then part quantity and device size are reduced, but illumination efficiency for each display decreases
Solution Approach 1:
The light guide plate incorporates local optical structures with varying properties at different positions to optimize light distribution. The refractive index, surface morphology, or structural characteristics change locally to direct light appropriately toward either the main display or sub-display region, ensuring efficient illumination for each specific area despite using a single backlight source.
Solution Approach 2:
The patent segments the light guide plate into functionally distinct regions with different optical characteristics. These segmented zones control light propagation paths differently, allowing efficient light delivery to both the main display and sub-display areas simultaneously, thereby maintaining illumination efficiency while using a unified backlight system.
4Illumination intensity
If multiple light guide plates and light sources are used, then illumination coverage is improved, but manufacturing cost increases
Solution Approach 1:
The single light guide plate is designed with universal optical structures that enable it to illuminate multiple display types (main and sub-displays) simultaneously, eliminating the need to manufacture and assemble multiple separate light guide plates and light sources, thereby reducing manufacturing cost.
Solution Approach 2:
The patent merges the illumination functions for both displays into a single light guide plate assembly, reducing the total number of components that need to be manufactured, inventoried, and assembled. This consolidation directly lowers manufacturing complexity and cost while maintaining adequate illumination coverage for both display regions.
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 design allows for efficient illumination of both displays while reducing the overall device size and parts count, lowering manufacturing costs by using a pair of light guide plates and a light source, and enhancing brightness through controlled light distribution.
Implementation Method 1
the light from the edge light propagates inside the light guide plate, and is reflected on light-emitting means provided on the light guide plate
Implementation Method 2
the light from the edge light propagates inside the light guide plate
Implementation Method 3
A diffusion sheet for diffusing the light emitted from the light guide plate is disposed on one main surface
Implementation Method 4
A plurality of prism-shaped protrusions are formed on the surface of this isotropic prism sheet to condense the light in the direction perpendicular to the ridge lines of the protrusions
Data Source
AI summary
All of LEDs 12a-12d are switched on in a case of illuminating a main display 21 mainly. Thus, each LED 12a-12d has a lighting region 22a-22d respectively, thereby illuminating the main display 21 entirely. Central LEDs 12b, 12c in LEDs 12a-12d are switched on in a case of illuminating a sub-display mainly. Thus, each LEDs 12b, 12c has a lighting region 22b, 22c respectively, thereby illuminating the sub-display 21b.