Curved Reflective Polarizer Wire-Grid Alignment for Stable Transmittance
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Solution Overview
Problem
Existing reflective polarizing optical elements with curved substrates experience partial degradation of transmission characteristics for polarized light due to the stretching of wire grid films during adherence, particularly at the outer circumferential portions.
Innovation Solution
The reflective polarizing optical element is designed with a substrate having a curved surface portion where the arraying direction of the wire grid film is aligned parallel to the short diameter of the substrate, and the extending direction of the wires is orthogonal to the arraying direction, with an angle between them kept within 45°, to minimize stretching and maintain optimal transmission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wire grid film is adhered to a curved substrate, then the reflective polarizing optical element can be formed, but transmission characteristics for polarized light partially degrade
Solution Approach 1:
The patent applies preliminary action by pre-heating the wire grid film to its transition temperature before adherence, and by pre-positioning the film in the desired orientation (with wires parallel to the short diameter direction) before the actual bonding process. This ensures the film is in the optimal state for adherence and maintains its structural integrity during the process, preventing degradation of transmission characteristics.
Solution Approach 2:
The patent utilizes parameter changes by controlling the temperature of the wire grid film during adherence. By heating the film to its transition temperature and maintaining it within a specific temperature range during the bonding process, the film's physical properties are optimized to reduce stretching and maintain uniform wire spacing, thereby preserving transmission characteristics for polarized light.
2Shape
If the wire grid film is stretched during adherence to the curved surface, then the film can conform to the substrate shape, but the spacing between wires becomes non-uniform
Solution Approach 1:
The patent changes the temperature parameter of the wire grid film during adherence, heating it to its transition temperature. This temperature change modifies the film's physical properties, allowing it to conform to the curved substrate surface while minimizing stretching and maintaining uniform wire spacing, thus resolving the contradiction between shape conformity and spacing uniformity.
Solution Approach 2:
The patent applies preliminary action by pre-positioning the wire grid film in the optimal orientation (wires parallel to the short diameter direction) and pre-heating it before adherence. This ensures the film is properly aligned and in the optimal physical state before being stretched to conform to the curved surface, minimizing non-uniform spacing.
3Ease of manufacture
If the wire grid film is adhered at arbitrary orientation, then the manufacturing process is simple, but transmission characteristics for polarized light degrade
Solution Approach 1:
The patent applies preliminary action by pre-positioning the wire grid film in the optimal orientation (with wires parallel to the short diameter direction) before adherence. This pre-alignment ensures that the film is correctly oriented to maintain transmission characteristics for polarized light, while the overall process remains relatively simple and does not require complex alignment mechanisms during the actual bonding process.
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 configuration reduces partial degradation of transmission characteristics for polarized light, ensuring the optical performance is maintained with minimal changes in transmittance and wire spacing, particularly at the outer circumference of the element.
Implementation Method 1
a reflective polarizing film for a polarization beam splitter having a wire grid structure
Data Source
AI summary
Provided is a reflective polarizing optical element includes: a substrate including a curved surface portion forming a curved surface, and having, in a plan view of an optical axis direction, when the curved surface portion has a shape surrounded by a plurality of arcs each forming a part of the same circle in the plan view, and by a line connecting ends of adjacent arcs among the plurality of arcs, a short diameter defined by the shortest diameter among diameters passing through a center point of the same circle; and a reflective polarizing film for a polarization beam splitter having a wire grid structure, the reflective polarizing film being configured to be adhered to the curved surface portion so that an angle formed between an arraying direction of wires in the reflective polarizing film and an extending direction of the short diameter of the substrate falls within 45°.