Negative-Positive Lens Pair for Thermal Focus and Aberration Control
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Solution Overview
Problem
Existing optical systems for imaging apparatuses face challenges in controlling focal position variations due to environmental temperature changes while also correcting various aberrations, as they often require lenses with limited material selection due to specific refractive index and Abbe number requirements.
Innovation Solution
An optical system is designed with a negative lens and a positive lens adjacent to each other, where the interval between them and their curvature radii satisfy specific inequalities, allowing for temperature compensation and aberration correction regardless of the sign of the temperature coefficient, enhancing material selection flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pair of positive lens and negative lens having large differences in refractive index and Abbe number is employed to control focal position variation, then temperature compensation is achieved, but material selection freedom is reduced and aberration correction becomes difficult
Solution Approach 1:
The patent changes the approach from using large differences in refractive index and Abbe number to using specific relationships between curvature radii and interval. By defining the relationship between the curvature radii of facing surfaces (R1 and R2) and the interval (d1) through specific inequalities, the patent achieves temperature compensation without requiring extreme material property differences, thus maintaining material selection freedom while achieving reliable focal position control
2Reliability
If lenses with specific refractive index and Abbe number requirements are used to control focal position variation, then temperature compensation is achieved, but aberration correction becomes difficult
Solution Approach 1:
The patent shifts from controlling focal position through material properties (refractive index, Abbe number) to controlling it through geometric parameters (curvature radii R1, R2 and interval d1). By establishing specific relationships between these geometric parameters through inequalities, the patent simultaneously achieves both focal position control and aberration correction, as geometric parameters can be optimized independently of material selection
Solution Approach 2:
The patent introduces a dynamic relationship between the interval d1 and temperature changes. The interval is designed to vary with temperature in a controlled manner, allowing the optical system to maintain focus across different temperatures. This dynamic adjustment of the interval compensates for thermal effects while maintaining aberration correction through the established geometric parameter relationships
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 system effectively controls focal position variations and corrects aberrations across varying environmental temperatures, maintaining good image forming performance as demonstrated by modulation transfer function curves at different temperatures.
Implementation Method 1
An optical system includes a negative lens and a positive lens adjacent to each other, in which an interval on an optical axis between the negative lens and the positive lens satisfies the following inequality (1)... curvature radii of facing lens surfaces of the negative lens and the positive lens satisfy the following inequality (2)
Data Source
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AI summary
An optical system includes a negative lens and a positive lens adjacent to each other, wherein the following inequalities are satisfied: 0.00 ≤ DAB ≤ 1.00, and 0.80 ≤ RA/RB ≤ 1.20, where DAB[mm] denotes a distance on an optical axis between the negative lens and the positive lens, and RA and RB denote curvature radii of facing lens surfaces of the negative lens and the positive lens, respectively, and wherein specific inequalities are satisfied.