In-Vehicle Camera Casing Composition for Warp and Moisture Stability
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Solution Overview
Problem
Existing casing members for in-vehicle cameras fail to maintain dimensional accuracy and prevent gas generation in high temperature and high humidity environments, leading to warp and optical misalignment, especially when exposed to large temperature and humidity changes in vehicle interiors.
Innovation Solution
A casing member made from a resin composition containing 100 to 300 parts by mass of fibrous and non-fibrous inorganic fillers and 10% by mass or less elastomer, with specific molding conditions to ensure shrinkage rates and water absorption rates are within defined limits, enhancing mechanical strength and preventing gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an elastomer is added to improve toughness for press fitting, then toughness is improved, but water absorbency increases and gas is generated in high temperature and humidity environments
Solution Approach 1:
The patent optimizes the elastomer content parameter to 10% by mass or less, balancing toughness improvement with prevention of excessive water absorbency and gas generation. This parameter control ensures the resin composition maintains both mechanical strength for press fitting and dimensional stability in high temperature humidity environments
Solution Approach 2:
The patent creates a composite resin composition combining PAS resin with controlled amounts of elastomer and inorganic fillers. This composite structure achieves synergistic effects where the elastomer provides toughness for press fitting while the PAS resin base and inorganic fillers maintain low water absorbency and prevent gas generation in high temperature humidity conditions
2Manufacturing precision
If PAS resin is used to maintain dimensional accuracy and prevent warp, then dimensional stability is improved, but toughness may be insufficient for press fitting
Solution Approach 1:
The patent creates a composite resin composition combining PAS resin with controlled amounts of elastomer and inorganic fillers. This composite structure achieves synergistic effects where the elastomer provides toughness for press fitting while the PAS resin base and inorganic fillers maintain low water absorbency and prevent gas generation in high temperature humidity conditions
Solution Approach 2:
The patent optimizes the elastomer content parameter to 10% by mass or less, balancing toughness improvement with prevention of excessive water absorbency and gas generation. This parameter control ensures the resin composition maintains both mechanical strength for press fitting and dimensional stability in high temperature humidity environments
3Manufacturing precision
If inorganic filler is added to increase roundness and prevent warp, then dimensional accuracy is improved, but toughness may be reduced
Solution Approach 1:
The patent creates a composite resin composition combining PAS resin with controlled amounts of elastomer and inorganic fillers. This composite structure achieves synergistic effects where the elastomer provides toughness for press fitting while the PAS resin base and inorganic fillers maintain low water absorbency and prevent gas generation in high temperature humidity conditions
Solution Approach 2:
The patent specifies different types of inorganic fillers (fibrous and non-fibrous) with specific particle size ranges (0.1 to 2.0 μm for non-fibrous, 0.01 to 3.0 mm for fibrous). This local quality differentiation optimizes both roundness improvement and toughness maintenance in different regions of the material structure
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 casing member maintains high dimensional accuracy and prevents gas generation, ensuring optical performance under high temperature and humidity conditions, particularly effective in vehicle environments.
Implementation Method 1
an absolute value of (shrinkage rate in a direction perpendicular to a flow direction)−(shrinkage rate in the flow direction) is 0.5% or less
Implementation Method 2
a water absorption rate of a molded product of 80 mm×80 mm×2 mm that is injection molded using the resin composition under conditions of a cylinder temperature of 320° C., a mold temperature of 140° C., and a holding pressure of 70 MPa is 0.3% or less when subjected to a hot water immersion test at 80° C. for 300 hours
Data Source
AI summary
A casing member for an in-vehicle camera, obtained by injection molding a resin composition that comprises 100 to 300 parts by mass of a total of a fibrous inorganic filler and a non-fibrous inorganic filler to 100 parts by mass of a polyarylene sulfide resin and has a content of an elastomer of 10% by mass or less, and satisfying the following conditions (A) and (B). (A) When a molded product of a predetermined shape is injection molded using the resin composition under predetermined conditions, an absolute value of (shrinkage rate in a direction perpendicular to a flow direction)−(shrinkage rate in the flow direction) is 0.5% or less. (B) A water absorption rate of a molded product of a predetermined shape that is injection molded using the resin composition under predetermined conditions is 0.3% or less when subjected to a predetermined hot water immersion test.