Luminance-Equalizing Sheet Curvature for Backlight Uniformity
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Solution Overview
Problem
Conventional image display apparatuses, such as liquid crystal televisions, face challenges in achieving uniform luminance across the screen due to the limited internal space in the peripheral areas, which restricts the use of common display mechanisms and results in luminance unevenness from the center to the periphery.
Innovation Solution
The image display apparatus incorporates a luminance-equalizing sheet made of polyethylene terephthalate (PET) with microscopic bubbles, strategically positioned support pins, and a diffuser panel to ensure uniform light distribution, with the luminance-equalizing sheet having varying hole diameters to smooth light emission from LEDs and the diffuser panel further reducing luminance unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a direct-lit backlight system is used to achieve a thin appearance, then the device thickness is reduced, but luminance uniformity from center to periphery deteriorates
Solution Approach 1:
The patent applies local quality by varying the hole diameters in the luminance-equalizing sheet - larger holes in peripheral areas and smaller holes in central areas. This non-uniform structure compensates for the natural luminance drop-off at the edges, achieving uniform luminance distribution while maintaining the thin direct-lit backlight design.
Solution Approach 2:
The patent changes the physical parameter of hole diameter across different regions of the luminance-equalizing sheet. By gradually varying the hole diameter from the center to the periphery, the light distribution is optimized to achieve uniform luminance while maintaining the thin profile of the direct-lit backlight system.
2Shape
If the peripheral portion is made thinner to achieve a thin appearance, then the aesthetic appearance is improved, but the ability to employ common display mechanisms deteriorates
Solution Approach 1:
The patent implements local quality through the non-uniform hole diameter distribution in the luminance-equalizing sheet, with different regions having optimized hole sizes tailored to their specific luminance requirements, allowing the thin peripheral design to achieve uniform luminance without compromising display quality.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the hole diameter parameter across the luminance-equalizing sheet to compensate for the thickness variation, enabling the thin peripheral portion to maintain proper light distribution and display mechanism functionality.
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 enables the image display apparatus to achieve greater luminance uniformity across the screen, maintaining the thin appearance while ensuring consistent image quality from the center to the peripheral areas.
Implementation Method 1
a luminance-equalizing sheet 107 having an outer edge 107e that substantially overlaps the outer edge 102e of the active area 102a
Implementation Method 2
a diffuser panel 106 that diffusely emits light from the light sources 113
Implementation Method 3
a reflective sheet 108 that is positioned between the light sources 113 and the luminance-equalizing sheet 107
Data Source
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AI summary
An image display apparatus (10) includes: a display panel (102); a back frame (111) including a flat portion (111A) and a side wall (111B); light sources (113) arranged in rows and columns at substantially equal intervals in the flat portion (111A); support pins (112) arranged in rows and columns at substantially equal intervals in positions in the flat portion (111A) and away from the light sources (113); a diffuser panel (106) diffusely emitting light from the light sources (113) toward the display panel (102); and a luminance-equalizing sheet (107) that is supported at intermediate positions on the support pins (112), between the diffuser panel (106) and the back frame (111), has an outer edge that substantially overlaps an outer edge of an active area of the display panel (102), and transmits part of the light from the light sources (113) toward the diffuser panel (106). The luminance-equalizing sheet (107) protrudes in a curved manner toward the side wall (111B) between the diffuser panel (106) and the side wall (111B) such that distance between the luminance-equalizing sheet (107) and the back frame (111) gradually decreases from an outer edge of the flat portion (111A) to an outer edge of the side wall (111B).