In-Vehicle Camera Lens Unit Temperature Stability
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Solution Overview
Problem
In-vehicle camera lenses face resolution reduction due to poor temperature characteristics of plastic lenses and expansion/contraction issues when glass lenses are mounted in resin holders.
Innovation Solution
The in-vehicle camera lens unit is configured with a combination of glass and plastic lenses, where the first, second, fifth, and sixth lenses are glass, and the third and fourth lenses are plastic, with the fifth and sixth lenses cemented, to stabilize temperature characteristics and correct focal shifts caused by temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If all lenses are made of plastic to reduce cost, then manufacturing cost is reduced, but temperature characteristics deteriorate and resolution is reduced at extreme temperatures
Solution Approach 1:
The patent applies different materials (glass or plastic) to different lenses based on their specific requirements. The first, second, fifth, and sixth lenses use glass for stable temperature characteristics, while the third and fourth lenses use plastic for cost reduction and aberration correction, achieving local optimization of material selection
Solution Approach 2:
The lens system uses a composite structure combining glass lenses and plastic lenses together in a single optical system. This allows the system to benefit from both the temperature stability of glass and the cost-effectiveness and aberration correction capabilities of plastic materials
2Reliability
If glass lenses are used to improve temperature characteristics, then temperature stability is improved, but cost increases compared to all-plastic lenses
Solution Approach 1:
Glass material is selectively applied only to lenses where temperature stability is critical (first, second, fifth, and sixth lenses), while plastic is used for other lenses, achieving local optimization rather than uniform material selection across the entire system
Solution Approach 2:
Instead of using glass for all lenses (excessive action), the patent uses glass for only the necessary portion of lenses (first, second, fifth, and sixth lenses) where temperature characteristics are most critical, achieving cost-effective partial application
3Reliability
If glass lenses are mounted in resin holders, then temperature characteristics are improved, but resolution is reduced due to holder expansion and contraction
Solution Approach 1:
The patent converts the harmful effect of resin holder expansion and contraction into a beneficial effect by using plastic lenses whose expansion and contraction characteristics match the holder, transforming the potential source of error into a compensating mechanism that maintains focus accuracy
Solution Approach 2:
The patent changes the material parameter of specific lenses from glass to plastic to match the thermal expansion characteristics of the resin holder, thereby changing the physical parameters of the lens system to compensate for holder deformation at extreme temperatures
4Ease of manufacture
If plastic lenses are used, then cost is reduced, but focal position shifts occur due to temperature-induced shape and refractive index changes
Solution Approach 1:
The patent converts the focal position shift caused by plastic lens temperature changes into a beneficial compensation mechanism. The plastic lenses' temperature-induced changes counterbalance the resin holder's expansion and contraction, maintaining overall focus accuracy while using cost-effective plastic material
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 maintains stable temperature characteristics and image resolution across a wide temperature range, reducing costs by using plastic lenses instead of all glass lenses, while ensuring a bright image with reduced aberration and chromatic aberration.
Implementation Method 1
even if the position of a lens is changed due to expansion or contraction of the holder caused by a change in the temperature, an influence of such a change can be corrected by a shift in the focal position caused by a change in the shape or a change in the refractive index of the plastic lens
Implementation Method 2
a shift in the focal position caused by a change in the shape or a change in the refractive index of the plastic lens
Implementation Method 3
aberration is reduced by configuring the fifth lens and the sixth lens to be a cemented lens
Data Source
Figure 1
Figure 2A~2C
AI summary
An in-vehicle camera lens unit having stable temperature characteristics even when lenses are mounted in a resin holder is provided. With an in-vehicle camera lens unit 10, a first lens 1, a second lens 2, a third lens 3, a diaphragm 7, a fourth lens 4, a fifth lens 5, and a sixth lens 6, which are disposed in this order from an object side to an image side, are held in a resin holder 100. The first lens 1, the second lens 2, the fifth lens 5, and the sixth lens 6 are glass lenses, and of the third lens 3 and the fourth lens 4 disposed on both sides of the diaphragm 7, the third lens 3, which is a meniscus lens, is a plastic lens, and the fourth lens 4, which is a double convex lens, is a glass lens.