Holographic Microstructures for Large Backlight Units
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Solution Overview
Problem
Nanoimprint technology faces challenges in manufacturing large-sized products with complex optical microstructures, as it is difficult to create imprint stencils, prone to defects, and experiences phase distribution changes due to lamination or filling between film layers, limiting mass production feasibility and product reliability.
Innovation Solution
A method involving the formation of a photopolymer film on a light guide plate, followed by holographic exposure to create planar refractive index modulated phase-type microstructures, which allows for the manufacture of large-sized products with cross-scale optical microstructures without altering the phase distribution of holographic lenses, thereby enhancing mass production feasibility and product reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If nanoimprint technology is used to form complex optical microstructures on large-sized products, then manufacturing cost is reduced and output is increased, but it is difficult to create imprint stencils and defects are prone to occur
Solution Approach 1:
The patent replaces the mechanical nanoimprint process with a holographic exposure process. Instead of using mechanical force to imprint patterns, the invention uses optical fields to directly write holographic microstructures into the photopolymer film, eliminating the need for complex mechanical stencils and reducing defects associated with mechanical imprinting.
Solution Approach 2:
The patent changes the fundamental parameter of the manufacturing process from mechanical deformation to optical field interaction. By using holographic exposure with specific wavelength light and photopolymer materials, the invention achieves microstructure formation through photochemical reactions rather than mechanical pressing, thereby improving precision and reducing defects.
2Ease of manufacture
If nanoimprint technology is used to form optical microstructures, then cost is reduced, but phase distribution changes occur due to lamination or filling between film layers
Solution Approach 1:
The patent performs the holographic exposure and microstructure formation in advance, before any lamination or filling processes occur. By pre-forming the optical microstructures in the photopolymer film at the desired location and orientation, the invention ensures that the phase distribution is established early and remains stable through subsequent manufacturing steps like lamination or filling.
3Device complexity
If conventional methods are used to form optical microstructures, then manufacturing process is simple, but it is difficult to manufacture large-sized products with complex microstructures
Solution Approach 1:
The patent transitions from two-dimensional planar patterning to three-dimensional holographic microstructure formation. By using volumetric holography, the invention creates complex three-dimensional optical microstructures directly within the photopolymer film, enabling large-sized products with intricate microstructures that cannot be achieved with conventional two-dimensional methods.
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 approach enables the production of large-sized products with complex optical microstructures, avoiding phase distribution changes during lamination or filling, thus improving the feasibility and reliability of mass production.
Implementation Method 1
forming a photopolymer film on one of the light incident surface and the light exit surface of the light guide plate; and performing holographic exposure on the photopolymer film to form the optical microstructure layer
Implementation Method 2
each of the plurality of optical microstructures is configured to cause at least a portion of light emitted from a corresponding LED chip to propagate in the light guide plate by total internal reflection
Data Source
AI summary
A backlight unit, a method for manufacturing the same and a display device are provided. The backlight unit includes a light guide plate, an LED layer and an optical microstructure layer. The light guide plate includes a light incident surface and a light exit surface opposite to the light incident surface. The LED layer is provided on the light incident surface of the light guide plate, and includes plural LED chips arranged in an array. The optical microstructure layer is provided on one of the light incident surface and the light exit surface of the light guide plate, and includes plural optical microstructures in one-to-one correspondence with the plural LED chips. Each of the plural optical microstructures is configured to cause at least a portion of light emitted from a corresponding LED chip to propagate in the light guide plate by total internal reflection.