Optical Member with Patterned Diffuser for Backlight Brightness Uniformity
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Solution Overview
Problem
Existing direct type backlight units suffer from brightness non-uniformity due to light reflection at interfaces and high manufacturing costs, primarily caused by the use of multiple diffusion films which also lead to light transmittance deterioration.
Innovation Solution
An optical member with a pattern part for light diffusion and an adhesive part is used, where the pattern part is non-adhesive only in areas corresponding to the light source, and the adhesive part is used elsewhere, allowing for an optical film to be stacked with an air layer only over the pattern part, minimizing light refraction and enhancing brightness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple diffusion films are used to prevent Mura defects, then brightness uniformity is improved, but manufacturing cost increases and thickness increases
Solution Approach 1:
The patent combines the functions of multiple diffusion films into a single optical member that integrates light diffusion and light guide capabilities. The optical member includes a light incident side and a light outgoing side with specific optical properties, eliminating the need for separate diffusion films while maintaining brightness uniformity.
Solution Approach 2:
The optical member performs multiple functions simultaneously: it acts as a light guide, a diffuser, and an optical interface. By making the optical member universal for these functions, the patent reduces the overall component count and simplifies the backlight unit structure.
2Illumination intensity
If multiple optical films are stacked with air layer, then light diffusion is improved, but light transmittance deteriorates due to refraction at interfaces
Solution Approach 1:
The patent extracts and eliminates the air layers from between the optical films. By removing this harmful intermediate medium, the patent prevents light refraction and reflection at interfaces, thereby improving light transmittance while maintaining light diffusion through the optimized optical member structure.
3Ease of manufacture
If adhesive part is applied to entire surface, then manufacturing simplicity is improved, but light reflection at interface increases causing brightness non-uniformity
Solution Approach 1:
The patent applies adhesive only to specific areas (the adhesive part) rather than the entire surface. The optical member is divided into a pattern part (non-adhesive) and an adhesive part, allowing localized bonding that prevents light reflection at interfaces in critical areas while maintaining manufacturing 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
This solution effectively diffuses light from the source to peripheral areas, balances light intensity, and reduces manufacturing costs by minimizing the need for multiple diffusion films, resulting in improved brightness uniformity and reduced light loss.
Implementation Method 1
a pattern part adjusting the intensity of a light
Implementation Method 2
light may be refracted at the interface between the optical film and the air layer
Data Source
AI summary
The present invention relates to an optical member, comprising: a light incidence surface; and a light-emitting surface which comprises a patterned portion intended for adjusting the intensity of light and formed at an area corresponding to a light source, and an adhesive portion disposed in an area other than the patterned portion. When the optical member of the present invention is applied to a backlight unit, the patterned portion, which diffuses the light from the light source, is formed in the area corresponding to the light source so as to effectively diffuse the light from the light source into the peripheral area. Also, the optical member and a diffusion plate are stacked via an air layer in the area corresponding to the light source (the area in which the patterned portion is disposed), and the optical member and the diffusion plate closely contact each other without an air layer in the remaining area, such that the intensity of the light transmitted between a light source portion and the peripheral portion may be adjusted with an improvement in the balance of brightness and uniformity.