Inclined LED Backlight for Uniform Large LCD Illumination
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Solution Overview
Problem
Existing LED backlight systems for large liquid crystal displays face challenges in achieving uniform luminance and reducing size, as they either require complex manufacturing processes or fail to effectively utilize low-angle radiation light, leading to limited screen size and increased thickness.
Innovation Solution
A backlight system with a wedge-shaped optical guide member that inclines LED light sources and uses a combination of flat planes to efficiently direct and reflect light, reducing the optical guide distance and allowing for a thinner, more cost-effective design that uniformly illuminates large areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If LED light sources are disposed on the side plane of the optical guide plate (side light type), then the structure is simpler, but the radiation distance becomes longer as display size increases, causing luminance to lower and screen size to be limited
Solution Approach 1:
The patent transitions from the side light type (LEDs on the side plane) to the just-under light type (LEDs on the back plane), changing the spatial dimension of LED placement. This dimensional change shortens the radiation distance from LEDs to the display surface, thereby maintaining high luminance even for large displays while keeping the structure relatively simple.
Solution Approach 2:
The patent changes the inclination angle parameter of the optical axis of LED light sources relative to the optical guide plate. By optimizing this angle, the system achieves uniform luminance distribution across large display areas while maintaining a compact structure, resolving the contradiction between structural simplicity and luminance maintenance.
2Length of stationary object
If conventional LED backlight systems are used for large displays, then the radiation distance is short, but luminance uniformity deteriorates due to LED directivity
Solution Approach 1:
The patent applies different inclination angles to different regions of the optical guide plate. The inclination angle is designed to gradually change from the center toward the edges, creating local variations in light reflection angles. This local quality adjustment ensures that light from LEDs with directivity is uniformly distributed across the entire display surface, solving the luminance uniformity problem.
Solution Approach 2:
The patent optimizes the inclination angle parameter of the optical axis of LED light sources. By setting the optical axis at a specific inclination angle relative to the optical guide plate, the system effectively utilizes light emission in the direction of highest luminance while achieving uniform illumination across large display areas, thereby maintaining both short radiation distance and high luminance uniformity.
3Manufacturing precision
If the number of LED light sources is increased to illuminate large areas uniformly, then luminance uniformity improves, but the thickness and cost of the display increase
Solution Approach 1:
The patent optimizes the inclination angle parameter of the optical axis of LED light sources relative to the optical guide plate. This parameter optimization allows a reduced number of LEDs to achieve uniform luminance distribution across large display areas, thereby reducing display thickness while maintaining luminance uniformity.
Solution Approach 2:
The patent designs the optical guide plate with continuous inclined surfaces that systematically redirect light from LEDs. This continuous optical path ensures that light from fewer LEDs is efficiently distributed across the entire display surface, maintaining uniform illumination without requiring additional light sources that would increase 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 solution enables high luminance and uniform illumination of large liquid crystal displays while reducing the number of light sources and the thickness of the display, making it thinner and more cost-effective.
Implementation Method 1
an optical guide member having an optical guide portion of a wedge shape on a plane facing each light emitting element, and the optical guide portion has a first flat plane generally perpendicular to the optical axis of each light emitting element for receiving light from each light emitting element and a second flat plane having a predetermined angle relative to the optical axis and intersecting the first flat plane at an acute angle for reflecting light
Data Source
AI summary
A light source includes a plurality of light emitting elements, and each light emitting element is disposed in such a manner that a direction of an optical axis of the light emitting element having a highest luminance is disposed at a predetermined inclination angle relative to a plane of the liquid crystal display. The optical guide member has an optical guide portion of a wedge shape having a first flat plane generally perpendicular to the optical axis of each light emitting element for receiving light from each light emitting element and a second flat plane having a predetermined angle relative to the optical axis and intersecting the first flat plane at an acute angle for reflecting light. A plurality of optical guide portions are disposed in a plane and formed integrally along a predetermined direction corresponding to the inclination direction of the light emitting elements.