Backlight Unit Light Guide Plate Zigzag Diffusion Pattern
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Solution Overview
Problem
Tandem-type backlight apparatuses experience luminance non-uniformity due to shadows, dark lines, or bright lines at the boundaries between light guide plates, which existing solutions fail to adequately address, and thermal expansion can exacerbate these issues leading to deformation or breakage.
Innovation Solution
The configuration includes unit light guide plates with LEDs aligned along one side, zigzag unit diffusion patterns on the surface, and additional diffusion patterns on the back, ensuring that the size and pitch of these patterns optimize light distribution to minimize luminance non-uniformity by creating contrasting patterns that reduce the visibility of boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If light guide plates are aligned in a tandem-type configuration, then the thickness of the image display apparatus is reduced, but luminance non-uniformity occurs at the boundaries between adjacent light guide plates
Solution Approach 1:
The patent applies local quality by creating luminance contrasting parts (brighter or darker regions) at specific locations within each backlight block, particularly near the boundaries between adjacent blocks. This is achieved through light guide structures that concentrate or diffuse light locally to create patterns that counteract the boundary effects, making the overall luminance distribution more uniform across the display surface.
Solution Approach 2:
The patent employs asymmetry by intentionally creating asymmetric luminance distributions within each backlight block. The light guide plates and diffusion patterns are designed to produce non-uniform luminance contrasting parts that asymmetrically compensate for the symmetric boundary problems between adjacent blocks, thereby achieving overall luminance uniformity.
2Reliability
If light guide plates are spaced apart with gaps to accommodate thermal expansion, then deformation and breakage are prevented, but shadow, dark line or bright line at boundaries becomes much conspicuous
Solution Approach 1:
The patent applies local quality by creating luminance contrasting parts (brighter or darker regions) at specific locations within each backlight block, particularly near the boundaries between adjacent blocks. This is achieved through light guide structures that concentrate or diffuse light locally to create patterns that counteract the boundary effects, making the overall luminance distribution more uniform across the display surface.
Solution Approach 2:
The patent converts the harmful effect of gaps (which cause conspicuous boundaries) into a benefit by designing light guide structures that create luminance contrasting parts within each block. These contrasting parts actively compensate for the boundary dark lines or bright lines caused by gaps, transforming the gap-induced problem into an opportunity for luminance uniformity enhancement.
3Device complexity
If only superposing light guide plates or adding acrylic plates is used to reduce boundary effects, then structure simplicity is maintained, but luminance non-uniformity cannot be sufficiently reduced
Solution Approach 1:
The patent applies local quality by creating luminance contrasting parts (brighter or darker regions) at specific locations within each backlight block, particularly near the boundaries between adjacent blocks. This is achieved through light guide structures that concentrate or diffuse light locally to create patterns that counteract the boundary effects, making the overall luminance distribution more uniform across the display surface.
Solution Approach 2:
The patent applies segmentation by dividing the backlight apparatus into multiple independent backlight blocks, each containing light guide plates and diffusion patterns. This segmentation allows each block to be optimized independently with specific luminance contrasting parts, while the collective arrangement of multiple blocks achieves overall luminance uniformity across the entire display 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 effectively reduces the conspicuousness of luminance non-uniformity across the entire screen by creating irregular and short intervals of luminance peaks, making bright or dark lines at boundaries less noticeable, while also accommodating thermal expansion without deformation.
Implementation Method 1
a plate-like light guide plate composed of a transparent material such as acrylic or the like... each of which guides surface light converted from light of the light source to a liquid crystal panel side
Implementation Method 2
unit diffusion patterns are formed on a light exit surface of the unit light guide plate... another diffusion pattern is formed on the back of the unit light guide plate
Implementation Method 3
a plurality of LED light sources and a unit light guide plate for guiding light from the light sources
Implementation Method 4
the light guide plate is comprised of resin such as acrylic or the like, so that it will cause thermal expansion due to heat from a light source such as LED
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A plurality of backlight blocks (4) are aligned, each block includes light sources and a unit light guide plate (5) for guiding light from the light sources to the side of a liquid crystal panel (1), unit diffusion patterns (61) are formed in a zigzag alignment on the unit light guide plate and another diffusion pattern is formed on the back of the unit light guide plate. One side of the unit light guide plate is defined as a light entrance surface and LEDs (7) as the light sources are aligned along the light entrance surface to satisfy p ≧ a ≧ c where a indicates the size of the unit diffusion pattern in a direction orthogonal to an exit optical axis of the LEDs, c indicates the size of an LED emission surface in the direction of alignment of the LEDs, and p indicates the pitch of alignment of the light sources.