Locally Dimmable Light Guide Plate with Optical Path Changing Units
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Solution Overview
Problem
Conventional edge-illumination type backlight units in LCDs operate in a fully turned-on state, leading to continuous uniform brightness across the display panel, resulting in excessive power consumption, as they do not support selective regional or local dimming techniques to adjust brightness according to image content.
Innovation Solution
A locally dimmable edge-illumination type backlight unit is designed with a light guide plate that includes optical path changing units and refractors to redirect and adjust light output from individually dimmable light sources, allowing for selective brightness control in specific areas of the display panel by bounding light output to predetermined regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If edge-illumination type backlight unit operates in fully turned-on state, then uniform brightness is provided across the entire display panel, but power consumption increases excessively
Solution Approach 1:
The backlight unit is divided into multiple independently controllable light sources arranged in an array, allowing selective activation of specific regions. Each light source corresponds to a specific display region, enabling localized brightness control rather than uniform illumination of the entire panel.
Solution Approach 2:
Different regions of the display panel are provided with different brightness levels according to the actual image content requirements. The optical path changing units redirect light locally to specific areas, creating non-uniform illumination patterns that match the display needs, thereby reducing power consumption in dark regions while maintaining brightness in bright regions.
2Device complexity
If conventional edge-illumination backlight unit is used, then simple structure is maintained, but selective regional dimming capability is lost
Solution Approach 1:
The backlight unit is segmented into multiple independently controllable light sources, with each light source corresponding to a specific display region. This segmentation enables selective activation and dimming of individual regions, providing adaptability for local dimming while maintaining a relatively simple overall structure.
Solution Approach 2:
Optical path changing units are introduced as intermediary components between the light sources and the display panel. These units redirect light from specific light sources to corresponding display regions, enabling selective regional dimming functionality without requiring complex control systems or additional hardware.
3Volume of moving object
If light sources are provided in vicinity of side edge portion, then slimness is achieved, but light distribution control becomes difficult
Solution Approach 1:
Multiple light sources are arranged in an array along the side edge of the light guide plate, maintaining the slim profile of the backlight unit. Each light source is independently controllable and corresponds to a specific display region, enabling precise light distribution control despite the edge-illumination configuration.
Solution Approach 2:
Optical path changing units serve as intermediaries that redirect light from the edge-mounted light sources to specific display regions. This intermediary mechanism enables precise control of light distribution across the display panel while maintaining the slim form factor achieved through edge illumination.
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 solution enables the reduction of power consumption by adjusting brightness in controllable display areas, optimizing light usage based on image content, thereby reducing unnecessary light output in darker regions and improving energy efficiency.
Implementation Method 1
The optical path changing units are aligned along at least the bottom surface of the top surface and the bottom surface at a predetermined repeat interval while protruding in parallel to a reference line perpendicular to the light incident surface
Implementation Method 2
The light guide plate may further include light refractors protruding outward from its light-outputting top surface and corresponding to the optical path changing units of its bottom surface
Data Source
AI summary
In a light guide plate and a backlight unit, a light guide plate includes a light incident surface, an opposite surface, a top surface, a bottom surface, and a plurality of optical path changing units. The optical path changing units are aligned on at least the bottom surface of the top surface and the bottom surface at a predetermined interval while protruding in parallel to a reference line perpendicular to the light incident surface. Accordingly, power consumption used to generate the light may be reduced.