Polarizing Optical Element Bonding via Pressure-Sensitive Adhesive
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Solution Overview
Problem
Existing methods for manufacturing polarizing optical elements, such as ophthalmic lenses, face challenges in achieving sufficient cohesion between the base optical element and the polarizing film, controlling the film's positioning, and maintaining optical quality, especially when using thermosetting or thermoplastic materials, which can lead to uncontrolled heating and deformation.
Innovation Solution
A method involving a layered structure with a pressure-sensitive adhesive material is used to bond a polarizing film containing oriented dichroic dyes to a base optical element, allowing for simple and inexpensive application without prolonged heating, ensuring precise positioning and maintaining optical quality, particularly suitable for progressive ophthalmic lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the polarizing film is placed inside the mold of the base optical element and polymerized by heating to 90-130°C for 20 hours, then the polarizing film is incorporated in a durable manner, but the tint of the polarizing film can vary, the polarization efficiency can be reduced, and the dimensional stability may be altered
Solution Approach 1:
The polarizing film is pre-formed to the desired curvature and positioned inside the mold before polymerization begins. This preliminary positioning ensures that the film maintains its correct location throughout the lengthy 20-hour polymerization process, preventing the uncontrolled fluctuations that occur when positioning is attempted during or after polymerization.
Solution Approach 2:
The monomer liquid acts as an intermediary medium that fills the mold around the polarizing film during polymerization. This intermediary substance allows the film to be incorporated durably while maintaining its position, as the polymerizing monomer provides a stable environment that prevents film displacement.
2Reliability
If the mold is heated to a maximum temperature of between 90° C. and 130° C. for polymerization, then the monomer liquid is polymerized to incorporate the polarizing film, but the polarization efficiency of the film can be reduced and the dimensional stability may be altered
Solution Approach 1:
The patent specifies a controlled temperature range of 90-130°C for polymerization. This parameter change optimizes the polymerization process to ensure complete curing of the monomer liquid while minimizing thermal damage to the polarizing film, thus maintaining its polarization efficiency and dimensional stability.
3Ease of manufacture
If the position of the polarizing film inside the mold is affected by the method of filling, then the position with respect to the front face can fluctuate, but this fluctuation is detrimental to the precision necessary for certain applications
Solution Approach 1:
The polarizing film is positioned inside the mold before the monomer liquid is poured in. This preliminary positioning ensures that subsequent filling operations do not displace the film, maintaining precise positioning throughout the manufacturing process.
4Ease of manufacture
If it is difficult to ensure parallelism between a face of the mold and the surface of the polarizing film, then the manufacture of progressive ophthalmic lenses is penalized, but parallelism is necessary for lenses whose radius of curvature varies continuously
Solution Approach 1:
The polarizing film is pre-formed to the desired curvature before being placed in the mold. This preliminary shaping ensures that the film's surface is already parallel to the mold face, eliminating the difficulty of achieving parallelism during the manufacturing process itself.
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 results in a polarizing optical element with improved optical quality, reduced thickness, and enhanced comfort due to weight reduction, while preserving the dioptric properties of the lens, and allows for flexible integration with various optical elements.
Implementation Method 1
A method involving a layered structure with a pressure-sensitive adhesive material is used to bond a polarizing film containing oriented dichroic dyes to a base optical element
Implementation Method 2
By dichroic dye is meant a species which may be of molecular or crystalline nature and which exhibits a privileged absorption of visible electromagnetic radiation for a particular spatial orientation
Implementation Method 3
stretching the film uniaxially so as to orient the molecules of dichroic dyes and/or or dichroic iodine crystals along the direction of stretching
Data Source
AI summary
The invention concerns a polarizing optical element comprising a basic transparent optical element (1) and a layered structure (2) incorporating a polarizing film (2a). The polarizing film is of the dichroic colouring type and uniaxially oriented. The layered structure is bonded on the basic optical element via a layered structure (3) including at least one pressure-sensitive adhesive material layer. Through the use of pressure-sensitive adhesive material, the polarizing film (2a) maintains during bonding a high polarizing efficiency and an optical quality compatible with the numerous applications of the optical element, in particular ophthalmological applications.