Zoom Lens Temperature Correction via Segmented Focusing Group
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Solution Overview
Problem
Conventional zoom lens devices require complex mechanisms to correct defocus caused by ambient temperature changes, especially in high magnification systems, which complicates the correction process.
Innovation Solution
A zoom lens device with a temperature-based correction lens that moves independently along the optical axis to correct focal point changes, allowing the focusing lens group positions to remain as initially set, simplifying the correction mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional correcting mechanism is used to correct defocus caused by ambient temperature changes, then defocus correction is achieved, but the correcting mechanism becomes complex requiring calculation of correction amounts for respective positions along the optical axis
Solution Approach 1:
The focusing lens group is segmented into a focusing lens and a separate temperature-based correction lens. The correction lens is independently movable along the optical axis in response to temperature changes, while the focusing lens maintains its preset position. This segmentation allows defocus correction without moving the entire focusing lens group, simplifying the correction mechanism.
Solution Approach 2:
The temperature-based correction function is extracted from the focusing lens group as a separate correction lens. This extracted correction lens operates independently to compensate for thermal defocus, separating the correction function from the primary focusing function and reducing the complexity of the overall correction mechanism.
2Reliability
If the positions of the focusing lens group and variator lens group are changed to correct defocus, then defocus correction is achieved, but the preset mechanism positions can no longer be used
Solution Approach 1:
The focusing lens group is divided into a focusing lens that maintains preset positions and a separate temperature-based correction lens that moves independently to correct defocus. This allows the preset mechanism to remain functional for positioning the focusing lens while the correction lens handles temperature compensation.
Solution Approach 2:
The temperature-based correction lens acts as an intermediary element between the preset mechanism and the requirements for temperature compensation. It absorbs the temperature-induced defocus without interfering with the preset positions established by the preset mechanism, allowing both functions to coexist.
3Reliability
If the focusing lens group is moved to correct defocus on the long focal length side, then defocus correction is achieved, but other lens groups also require temperature-based corrections
Solution Approach 1:
The temperature-based correction lens is specifically designed to address defocus in the focusing lens group on the long focal length side. By localizing the correction function to this specific region, the patent avoids the need for temperature-based corrections in other lens groups, simplifying the overall system.
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
Effectively eliminates defocus on the long focal length side by moving only the temperature-based correction lens, reducing the need for temperature-based corrections in other lens groups and maintaining preset positions irrespective of ambient temperature changes.
Implementation Method 1
a change in shape caused by an ambient temperature change around the focusing lens group on the long focal length side largely affects focusing of the entire zoom lens device
Data Source
AI summary
A zoom lens device includes a focusing lens group arranged on an object side, and a variator lens group next thereto, and a temperature sensor. The focusing lens group includes a focusing lens, and a temperature-based correction lens for correcting changes in focal point caused by temperature changes around the focusing lens group. The temperature-based correction lens is moved by a temperature-based correction lens driving mechanism along an optical axis to a position determined by a temperature detected by the temperature sensor, independently of the positions of the focusing lens or variator lens group. Thereby, the zoom lens device is capable of favorably correcting defocus of the lens group caused by an ambient temperature change with a simple correcting mechanism.