Transfer Film With Optically Anisotropic Layer For Image Display
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Solution Overview
Problem
Transfer films with optically anisotropic layers used in image display apparatus often exhibit defects when observed under external light, due to issues like wrinkles caused by dust or dimensional changes, which affect the accuracy of defect inspection and the quality of the final product.
Innovation Solution
A transfer film with a temporary support having an in-plane retardation of 0 to 20 nm at 550 nm, an optically anisotropic layer formed from a liquid crystal compound with specific alignment and twist angles, and a method involving curing and potential superheated steam treatment to minimize dimensional changes and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transfer film with optically anisotropic layer is used in image display apparatus, then the apparatus can achieve optical compensation functions, but defects such as wrinkles and dimensional changes occur when observed under external light
Solution Approach 1:
The patent applies parameter changes by precisely controlling the in-plane retardation of the temporary support substrate to be 0 to 20 nm at 550 nm, and controlling the dimensional change rate of the optically anisotropic layer to within ±0.05% after 8 days of standing. These parameter specifications resolve the contradiction by ensuring both optical compensation performance and dimensional stability through controlled material properties and environmental exposure.
Solution Approach 2:
The patent implements preliminary action by pre-aligning the liquid crystal compound in the optically anisotropic layer before final assembly, and by pre-controlling the in-plane retardation of the temporary support substrate. This preliminary preparation prevents wrinkles and dimensional changes from developing during subsequent handling and assembly processes, thereby eliminating defects while maintaining optical compensation functionality.
2Measurement precision
If defect inspection is performed on transfer films, then quality control is improved, but wrinkles and dimensional changes cause false defects to be detected
Solution Approach 1:
The patent resolves the contradiction between defect detection accuracy and surface flatness by controlling the in-plane retardation parameter of the temporary support to be 0 to 20 nm and the dimensional change rate of the optically anisotropic layer to within ±0.05%. These parameter controls prevent the formation of wrinkles and dimensional variations that would otherwise be detected as defects during inspection, thereby improving both measurement precision and manufacturing precision simultaneously.
3Manufacturing precision
If the optically anisotropic layer is allowed to stand for 8 days in controlled environment, then dimensional stability is assessed, but significant dimensional changes occur with conventional materials
Solution Approach 1:
The patent applies parameter changes by specifying that the dimensional change rate of the optically anisotropic layer must be within ±0.05% after 8 days of standing in a controlled environment (25°C, 60% RH). This parameter specification ensures both dimensional stability and structural integrity by selecting materials and conditions that prevent excessive dimensional changes while maintaining layer structure integrity during the assessment period.
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 accurate defect inspection and reduces the occurrence of wrinkles, resulting in image display apparatus with fewer defects when observed under external light, improving the overall quality and reliability of the product.
Implementation Method 1
An optically anisotropic layer having refractive index anisotropy is applied to various applications such as an antireflection film of an image display apparatus and an optical compensation film of a liquid crystal display device.
Implementation Method 2
the optically anisotropic layer is a layer formed of a liquid crystal compound, and in a case where the optically anisotropic layer obtained by peeling the temporary support from the transfer film is allowed to stand for 8 days in an environment with a temperature of 25° C. and a relative humidity of 60%
Data Source
AI summary
A transfer film in an image display apparatus includes a temporary support including a substrate and an optically anisotropic layer, in which an in-plane retardation of the substrate at a wavelength of 550 nm is 0 to 20 nm, the optically anisotropic layer is formed of a liquid crystal compound, and where the optically anisotropic layer obtained by peeling the temporary support from the transfer film is allowed to stand in a predetermined environment, and then a maximum value of a dimensional change rate in an in-plane direction of the optically anisotropic layer is defined as ΔL (max) and a minimum value of the dimensional change rate is defined as ΔL (min), the transfer film satisfies at least one of Expression (1) ΔL (max)/ΔL (min)≤1.5 or Expression (2) ΔL (max)≤0.08%.