Biaxial Oriented Polyester Reflection Film With Grid Light Focusing Structures
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Solution Overview
Problem
Existing reflection films for liquid crystal displays (LCDs) face challenges in maintaining dimensional stability and reflective properties during high-temperature forming processes, leading to deformation and reduced light interference management.
Innovation Solution
A biaxially oriented polyester reflection film with a core layer containing voids, homo-polyester, copolymer polyester, an incompatible resin, and inorganic particles, and a skin layer with specific composition and thickness ratios, arranged in a grid pattern with concave light focusing structures, is developed to enhance formability and dimensional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If high temperature heating is applied to form the reflection film, then the film can be shaped into desired concave portions and holes, but the existing reflection film deforms and loses dimensional stability causing voids to deform and reflective properties to degrade
Solution Approach 1:
The patent applies parameter changes by carefully controlling temperature and time parameters during the heating process. The reflection film is heated to a specific temperature range (Tg+10℃ to Tm-10℃) for a controlled duration, which enables sufficient formability while preventing excessive deformation and maintaining dimensional stability after forming.
Solution Approach 2:
The patent uses a composite material structure consisting of a polyester base resin combined with specific additives including void-forming agents and inorganic particles. This composite formulation enhances both the formability during heating and the dimensional stability after forming, while maintaining reflective properties through the controlled creation and stabilization of void structures.
2Shape
If high temperature heating is applied to form the reflection film, then the film can be shaped into desired concave portions and holes, but the mounted LEDs may be separated due to dimensional change
Solution Approach 1:
The patent controls the heating parameters (temperature and time) to enable formability while minimizing dimensional changes that would cause LED separation. The temperature is maintained within a specific range and the heating duration is optimized to achieve the desired shape without excessive expansion or contraction that would displace mounted LEDs.
Solution Approach 2:
The patent incorporates dimensional stability considerations into the film formulation and processing design beforehand. By using a composite material with controlled thermal properties and optimized void structure, the film is pre-conditioned to resist excessive dimensional changes during heating, thereby protecting mounted LEDs from separation before the forming process even begins.
3Illumination intensity
If voids are formed in the reflection film to improve reflective properties, then light reflection is enhanced, but the voids may deform during high temperature forming process
Solution Approach 1:
The patent uses a composite material system where the polyester base resin is combined with specific void-forming agents and inorganic particles. This composite structure enables the formation of stable voids that maintain their shape and distribution during high-temperature forming, while still providing the desired reflective properties through controlled light scattering and reflection.
Solution Approach 2:
The patent controls the thermal processing parameters to prevent void deformation while maintaining reflective properties. By heating within a specific temperature range and for a controlled time, the voids are formed and stabilized without excessive deformation, preserving both the reflective function and structural integrity.
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 film maintains excellent reflective properties and dimensional stability before and after forming, enabling effective light management for local dimming in LCDs, with spectral reflectivity of 95% or higher and minimal change, and a dimensional change rate of less than 5% over time.
Implementation Method 1
a reflection film which reflects light back to the front when light is lost to the back of a display
Implementation Method 2
a prism film which focuses the diffused light onto the front
Data Source
AI summary
A biaxially oriented polyester reflection film according to an embodiment of the present invention includes: a core layer having a plurality of voids, and containing homo-polyester, copolymer polyester, a resin incompatible with polyester, and inorganic particles; and a skin layer formed at least one surface of the core layer, and containing homo-polyester, copolymer polyester, and inorganic particles, wherein the biaxially oriented polyester reflection film is formed to have a plurality of light focusing structures, each of which has a concave center portion, and which are arranged in a grid pattern.