Curved Beam Control Elements for LCD Backlight Uniformity
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Solution Overview
Problem
Conventional backlights for liquid crystal display devices face challenges in achieving high brightness and uniformity, particularly with linear or dotted beam control elements on light guide plates, which can lead to irregularities in brightness distribution and limitations in maximum product brightness.
Innovation Solution
The solution involves forming beam control elements in a curved pattern around LEDs on the light guide plate and a linear triangular crest-or-groove pattern further away, along with the use of a prism sheet to ensure uniform light incidence, allowing for increased brightness and reduced irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If beam control elements are arranged linearly or in dotted patterns on the light guide plate, then the structure is simple and easy to manufacture, but brightness uniformity deteriorates and irregularities are generated
Solution Approach 1:
The patent applies different beam control element patterns to different regions of the light guide plate. Specifically, curved beam control elements are formed in the vicinity of the LED to address local brightness irregularities, while linear patterns are used in remote regions. This localized differentiation allows the system to maintain manufacturing simplicity while achieving superior brightness uniformity where needed.
Solution Approach 2:
The patent introduces curved beam control elements that follow an arcuate path centered on the LED position. This curvature is specifically designed to compensate for the directional light emission characteristics of LEDs, redistributing light more uniformly across the display panel and eliminating the brightness irregularities that occur with conventional linear arrangements.
2Length of stationary object
If the distance from LED to effective display region is narrowed to reduce picture frame, then device compactness is improved, but brightness irregularities increase
Solution Approach 1:
The curved beam control elements are specifically designed to work with reduced LED-to-display distances. The arcuate pattern centered on the LED creates optimal light distribution paths that compensate for the shorter distance, maintaining brightness uniformity even when the picture frame is narrowed to improve device compactness.
3Illumination intensity
If distance between LEDs is increased to realize higher brightness, then LED brightness is improved, but brightness irregularities in the vicinity of LED increase
Solution Approach 1:
The patent applies enhanced curved beam control elements specifically in the vicinity of each LED to address local brightness irregularities. This localized approach allows the system to use higher brightness LEDs with larger spacing while preventing the formation of brightness hotspots and irregularities through the specialized curved pattern design.
4Manufacturing precision
If concentric or arcuate beam control elements are formed on the whole surface, then brightness uniformity is improved, but device complexity increases and maximum product brightness cannot be increased
Solution Approach 1:
Instead of applying uniform curved beam control elements across the entire light guide plate surface, the patent localizes the curved pattern formation to only the vicinity of the LED. This selective approach achieves the necessary brightness uniformity improvement while avoiding the increased manufacturing complexity that would result from forming curved patterns across the whole surface.
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 enhances brightness uniformity by up to 30-50% in the front direction, reduces part costs and assembly time, and maintains display quality by minimizing brightness irregularities near the LED, making it suitable for various liquid crystal display devices from mobile phones to large screens.
Implementation Method 1
a light guide plate as a light source
Implementation Method 2
light guide plate which can reduce in-plane irregularities
Implementation Method 3
beam control elements in which concave shapes or convex shapes having a triangular cross section are formed linearly
Implementation Method 4
interposing a prism sheet which arranges a prism surface on a light radiation surface side of the light guide plate
Data Source
AI summary
The present invention makes a radiation angle of light at a portion of a light guide plate in front of an LED formed on one edge of a light guide plate and a radiation angle of light at a corner portion of the light guide plate equal to each other as much as possible. A shape of beam control elements which are arranged on a lower surface of a light guide plate is arranged concentrically about the LED.