Alicyclic Polyester Optical Lens for High Heat Resistance
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Solution Overview
Problem
Conventional optical lens materials, such as calcium fluoride, aromatic ring-containing polyester resins, and bisphenol A-based polycarbonates, face challenges including high production costs, poor heat resistance, high birefringence, and high water absorption, making them unsuitable for applications requiring superior optical characteristics and environmental resistance, especially in close proximity to heat sources like vehicle-mounted cameras.
Innovation Solution
An optical lens comprising a polyester resin with a specific alicyclic structure, which includes a unit with a particular formula, offering improved heat resistance, low water absorption, and optimal optical characteristics like refractive index, Abbe's number, and photoelastic coefficient, thereby addressing the limitations of existing materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If optical glasses are used, then heat resistance and transparency are improved, but material cost and processing complexity increase
Solution Approach 1:
The patent modifies the chemical structure parameters of polyester resin by introducing specific alicyclic structures (cyclohexane rings) and controlling the molar ratios of structural units. This changes the material's fundamental properties to achieve heat resistance comparable to optical glasses while maintaining the moldability advantages of plastics. The glass transition temperature is elevated to 120°C or higher through these structural modifications.
Solution Approach 2:
The patent creates a composite-like structure within the polyester resin by incorporating multiple functional structural units: alicyclic units for heat resistance, specific diol units for optical property control, and balancing units for mechanical stability. This multi-component molecular architecture achieves the performance of composite materials while remaining a processable thermoplastic resin.
2Ease of manufacture
If conventional polyester resins are used, then ease of manufacture is improved, but optical characteristics (birefringence, photoelastic coefficient) worsen
Solution Approach 1:
The patent applies local quality by strategically placing specific structural units at different positions within the polymer chain. The alicyclic structural units are positioned to provide localized heat resistance, while specific diol units are arranged to control optical anisotropy. This spatial arrangement of functional groups within the resin structure enables simultaneous optimization of manufacturability and optical precision.
Solution Approach 2:
The patent precisely controls the molar ratios of different structural units as key parameters: alicyclic structural units (5-50 mol%), specific diol units (10-60 mol%), and balancing units (10-50 mol%). By adjusting these compositional parameters, the patent optimizes both the ease of manufacture and the optical characteristics, achieving low birefringence and photoelastic coefficient while maintaining good moldability.
3Illumination intensity
If polymethyl methacrylate is used, then transparency is improved, but water absorption and heat resistance worsen
Solution Approach 1:
The patent extracts the problematic ester linkages and hydrophobic groups from polymethyl methacrylate that cause high water absorption. Instead, it incorporates hydrophobic alicyclic structures (cyclohexane rings) and carboxylic acid groups that provide both low water absorption and high transparency. The resulting polyester resin achieves water absorption of 0.2% or less while maintaining excellent optical clarity.
Data Source
Figure 1~2
Figure 3
AI summary
An object is to provide an optical lens having low water-absorbing capacity and superior in heat resistance, transparency, and optical characteristics (refractive index, Abbe's number, and photoelastic coefficient). The optical lens includes a polyester resin containing a unit (A) of the following formula (1).