Thin Backlight Unit Light Diffusing Film Brightness
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Solution Overview
Problem
Conventional backlight units with thin light conducting plates experience a reduction in brightness for the frontal direction due to the mismatch between the light diffusing films and the thinner plates, as the films are designed for thicker plates and fail to improve brightness effectively.
Innovation Solution
An edge light type backlight unit is developed using a light conducting plate with a thickness of 1.0 mm or smaller, combined with a light diffusing film featuring a binder resin and a light diffusing agent with a coefficient of variation in particle size distribution of 30% or smaller, which enhances the uniformity of the surface profile and suppresses interference patterns, ensuring high brightness for the frontal direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a thin light conducting plate is used to make the backlight unit thinner, then the thickness of the backlight unit is reduced, but brightness for the frontal direction decreases
Solution Approach 1:
The invention changes the particle size distribution parameters of the light diffusing agent (coefficient of variation ≤30%, mean particle size 5-10 μm) to optimize light diffusion characteristics. This parameter optimization ensures that even with a thin light conducting plate (1.0 mm or smaller), the light diffusion film can effectively redirect light at 60-90° angles toward the frontal direction, maintaining brightness while enabling thinner backlight unit design.
Solution Approach 2:
The invention applies a specifically designed light diffusion layer with controlled particle distribution to the light projecting surface of the thin light conducting plate. This localized treatment creates a uniform surface profile with appropriate convex portions that selectively redirect oblique light rays, compensating for the reduced light conducting capability of the thin plate in specific regions where brightness is needed.
2Device complexity
If a conventional light diffusing film is used with a thin light conducting plate, then the structure is simple, but brightness for the frontal direction is reduced
Solution Approach 1:
The invention optimizes the particle size parameters of the light diffusing agent (coefficient of variation ≤30%, mean particle size 5-10 μm) to create effective light diffusion without adding structural complexity. This parameter-optimized single-layer light diffusion film replaces conventional multi-layer structures, maintaining simplicity while achieving superior brightness performance with thin light conducting plates.
Solution Approach 2:
The invention creates a composite light diffusion layer by combining binder resin with light diffusing agents of specifically controlled particle size distribution. This composite material structure provides both mechanical integrity and optimized optical properties, enabling effective light diffusion in a single layer without requiring multiple conventional film layers, thus maintaining structural simplicity.
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 maintains high brightness for the frontal direction even with a thin light conducting plate, preventing the reduction in brightness typically seen with thinner designs, while also allowing for a thinner backlight unit structure.
Implementation Method 1
a light diffusing layer formed from a binder resin and a light diffusing agent, and the light diffusing agent has a coefficient of variation of particle size distribution of 30% or smaller
Data Source
AI summary
A backlight unit does not show decrease of brightness for the frontal direction even when made thin-shaped. An edge light type backlight unit 1 includes a light conducting plate 14, a light source 13 disposed along at least one end portion of the light conducting plate 14, and a light diffusing film 15 disposed on a light projecting surface of the light conducting plate 14. The light conducting plate 14 has a thickness of 1.0 mm or smaller, the light diffusing film 15 has a light diffusing layer formed from a binder resin and a light diffusing agent, wherein the coefficient of variation of particle size distribution of the light diffusing agent is in the range of 30% or smaller.