Optical Sheet Laminate for Backlight Luminance and Power
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Solution Overview
Problem
Portable information devices such as laptops and tablets require lower power consumption while maintaining high luminance, which existing direct-type backlight units fail to achieve efficiently with conventional optical sheet configurations.
Innovation Solution
An optical sheet laminate comprising a diffusion sheet with inverted quadrangular pyramid recesses and a pair of prism sheets with perpendicular prism directions, arranged at specific intersecting angles to enhance luminance uniformity and reduce power consumption, is integrated into the backlight unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional optical sheet configurations are used in direct-type backlight units, then the structure is simple and easy to manufacture, but the luminance is insufficient and power consumption is high
Solution Approach 1:
The patent changes the geometric parameters of the optical sheets by specifying precise intersecting angles (20-70 degrees) between the diffusion sheet recesses and prism sheet extending directions. This parameter optimization maximizes light extraction efficiency and luminance output while minimizing the required light source power, directly resolving the contradiction between achieving high luminance and reducing power consumption
Solution Approach 2:
The patent employs a composite optical sheet laminate structure combining a diffusion sheet with inverted quadrangular pyramid recesses and prism sheets with perpendicular extending directions. This composite configuration synergistically enhances light diffusion and extraction efficiency, achieving high luminance with reduced power consumption by optimizing the interaction between different optical components
2Illumination intensity
If the intersecting angle between diffusion sheet recesses and prism sheet extending direction is near 0° or 90°, then the arrangement is simple, but the luminance is lower
Solution Approach 1:
The patent optimizes the intersecting angle parameter to a specific range (20-70 degrees) to maximize luminance output. This parameter change transforms the optical interaction between diffusion and prism structures, achieving superior light extraction efficiency compared to conventional 0° or 90° arrangements, while the angle specification remains within manufacturable ranges
3Stability of the object's composition
If multiple diffusion sheets are arranged in layers, then the luminance uniformity improves, but the backlight unit thickness increases
Solution Approach 1:
The patent optimizes the configuration parameters of the diffusion sheet recesses (shape, size, arrangement density) to achieve maximum luminance uniformity with minimal sheet thickness. By precisely controlling the recess geometry and intersecting angles, the patent achieves uniform light distribution while minimizing the cumulative thickness of multiple diffusion sheets, resolving the contradiction between uniformity and 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 higher luminance with lower power consumption by optimizing the angle between the diffusion sheet's recesses and prism sheets, improving luminance uniformity and reducing the backlight unit's thickness.
Implementation Method 1
an optical sheet such as a diffusion sheet or a prism sheet is used to diffuse light emitted from a light source such as a light emitting diode (LED) to improve uniformity of luminance
Implementation Method 2
a pair of prism sheets having prism extending directions perpendicular to each other
Data Source
AI summary
An optical sheet laminate 100 is to be incorporated into a backlight unit 40 having white light sources 42. The optical sheet laminate 100 include: a diffusion sheet 43 having a first surface 21a having a plurality of recesses 22 having a substantially inverted quadrangular pyramid shape; and a pair of prism sheets 44 and 45 having prism extending directions perpendicular to each other. The diffusion sheet 43 includes one or a plurality of diffusion sheets in layers. The plurality of recesses 22 are arranged in a two-dimensional matrix, and the intersecting angle between an arrangement direction of the plurality of recesses 22 and the prism extending direction is 20° or more and 70° or less.