Resin Projection Lens Mounting for Thermal Expansion Stability
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Solution Overview
Problem
Existing projection lenses made of resin face challenges in maintaining performance under high-temperature environments due to thermal expansion, leading to deformation and potential cracking, especially when used in transportation equipment like automobiles.
Innovation Solution
A projection lens design featuring a first holding frame made of fiber-reinforced resin with a higher thermal expansion coefficient than a second metal holding frame, which absorbs thermal expansion and maintains lens alignment by acting as a buffer, preventing deformation and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a resin lens is used in a projection optical device, then weight is reduced and manufacturing cost is lowered, but the lens deforms and cracks under high-temperature conditions due to thermal expansion
Solution Approach 1:
The patent changes the thermal expansion parameter by selecting a holding frame material with a thermal expansion coefficient higher than that of the resin lens. This allows the holding frame to expand more than the lens during temperature changes, creating compressive stress that prevents lens deformation and cracking while maintaining the benefits of using a lightweight resin material.
Solution Approach 2:
The patent utilizes differential thermal expansion between the resin lens and the holding frame. By choosing a holding frame material (such as aluminum or aluminum alloy) with a higher thermal expansion coefficient than the resin lens, the system leverages the greater expansion of the holding frame to apply compressive stress on the lens during heating, preventing lens failure while maintaining optical performance.
2Reliability
If the holding frame is made of a material with high thermal expansion coefficient, then thermal expansion stress is increased, but this prevents resin lens deformation and cracking
Solution Approach 1:
The patent converts the potentially harmful thermal expansion stress into a beneficial compressive stress. By using a holding frame material with higher thermal expansion coefficient than the resin lens, the differential expansion during heating creates compressive stress on the lens that prevents deformation and cracking, transforming what could be a damaging force into a protective mechanism.
3Manufacturing precision
If the holding frame directly contacts the lens, then positioning precision is improved, but thermal expansion causes lens deformation and cracking
Solution Approach 1:
The patent changes the material parameter of the holding frame to have a higher thermal expansion coefficient than the resin lens. This parameter change allows the holding frame to expand more during temperature changes, creating compressive stress that prevents lens deformation while maintaining direct contact for precise positioning.
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 design effectively maintains lens performance by absorbing thermal expansion, ensuring precise optical alignment and preventing deformation or cracking of resin lenses under high-temperature conditions.
Implementation Method 1
a thermal expansion coefficient of the first holding frame is higher than a thermal expansion coefficient of the second holding frame
Data Source
AI summary
A projection lens includes a lens that is made of a resin, a first holding frame that holds the lens, and a second holding frame that is not in contact with the lens and holds the first holding frame; and a thermal expansion coefficient of the first holding frame is higher than a thermal expansion coefficient of the second holding frame.