Lens Device Focus Shift Correction via External Temperature Sensors
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Solution Overview
Problem
Existing lens devices face challenges in preventing focus shift due to heat without compromising design freedom, as temperature sensors either directly attached to lenses or placed within the lens barrel can interfere with optical characteristics and reduce design flexibility.
Innovation Solution
A lens device with a first temperature sensor outside the lens barrel to detect the lens barrel's temperature and a second temperature sensor outside to detect a target with a different temperature characteristic, using this information to control a correction lens and correct focus shifts without the need for sensors within the lens barrel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is directly attached to a lens within the lens barrel, then focus shift correction accuracy is improved, but the degree of freedom of design decreases due to interference with optical characteristics and wiring routing
Solution Approach 1:
The temperature sensor is extracted from the interior of the lens barrel and relocated to the exterior surface. This allows the sensor to measure the temperature of the lens barrel without being physically attached to the lenses, thereby maintaining optical characteristics while enabling focus shift correction
Solution Approach 2:
The lens barrel serves as an intermediary object between the temperature sensor and the lenses. By measuring the lens barrel's temperature instead of directly attaching sensors to lenses, the system indirectly obtains temperature information relevant to focus shift while avoiding optical interference
2Measurement precision
If a temperature sensor is placed within the lens barrel, then temperature measurement of lenses is improved, but device complexity increases due to space constraints and wiring routing requirements
Solution Approach 1:
The temperature sensor is extracted from the constrained interior space of the lens barrel and positioned on the exterior surface. This eliminates the need for complex wiring routing through the lens barrel and removes space constraints, significantly reducing device complexity
Solution Approach 2:
The temperature measurement approach transitions from a three-dimensional interior placement problem to a two-dimensional surface mounting problem. By moving the sensor to the exterior surface, the system gains spatial freedom and avoids the complexity of interior wiring and space management
3Measurement precision
If temperature sensors are placed inside the lens barrel, then focus shift detection is improved, but manufacturing costs increase due to additional components and assembly complexity
Solution Approach 1:
The temperature sensor is relocated from the interior to the exterior of the lens barrel, simplifying the assembly process. This reduces manufacturing costs by eliminating the need for precise interior mounting and complex wiring integration, while still enabling accurate focus shift detection
Solution Approach 2:
The lens barrel itself serves as the mounting structure for the temperature sensor, utilizing its own surface area and thermal mass. This self-service approach eliminates the need for additional interior mounting components and reduces assembly complexity, thereby lowering manufacturing costs
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 approach effectively prevents focus shifts caused by heat changes while maintaining design flexibility and reducing manufacturing costs by eliminating the need for sensors within the lens barrel, improving correction accuracy and reducing stray light and light shielding issues.
Implementation Method 1
a first temperature sensor that is provided outside the lens barrel to detect a temperature of the lens barrel
Implementation Method 2
a second temperature sensor that is provided outside the lens barrel to detect a temperature of a target of which a temperature characteristic indicating a temperature change with a time change is different from a temperature characteristic of the lens barrel
Implementation Method 3
a lens which causes a focus shift of the imaging optical system due to expansion or contraction caused by the influence of heat
Data Source
AI summary
Provided are a lens device capable of preventing a focus shift of an imaging optical system due to heat without reducing a degree of freedom of design, an imaging device comprising the same, and a focus shift correction method of a lens device. A lens device 100 includes an imaging optical system 20 that includes a plurality of lenses, a lens barrel 10 that accommodates the imaging optical system 20, a temperature sensor 30 that is provided outside the lens barrel 10 to detect a temperature of the lens barrel 10, a temperature sensor 50 that is provided outside the lens barrel 10 to detect a temperature of a member 40 of which a temperature characteristic indicating a temperature change with a time change is different from a temperature characteristic of the lens barrel 10, and a focus correction unit 60 that corrects a focus shift of the imaging optical system 20 by controlling a relay lens 25 as a correction lens included in the imaging optical system 20 based on temperature information items respectively detected by the temperature sensor 30 and the temperature sensor 50.