Image Pickup Unit Prism Rotation Focus Shift Compensation
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Solution Overview
Problem
Conventional endoscope image pickup units face challenges in maintaining a favorable depth of field when changing the visual field direction, particularly as the angle of rotation exceeds 30°, leading to a shift in the focused range towards the near-point side, which affects image quality.
Innovation Solution
The image pickup unit incorporates a prism rotating section and a focusing section that adjusts the air space between the prism and the lens group, allowing the focused range to move towards the near-point side as the visual field direction angle increases beyond 30°, ensuring a stable depth of field through the rotation of the prism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the prism is rotated to change the visual field direction, then the visual field direction can be changed, but the focused range shifts toward the near-point side when the rotation angle exceeds 30°, affecting image quality
Solution Approach 1:
The patent applies the dynamics principle by making the air space between the prism and lens group variable rather than fixed. The focusing section dynamically adjusts the air space based on the prism rotation angle, allowing the system to adapt the optical path length to maintain proper focusing across different visual field directions. This resolves the contradiction by enabling visual field changes while compensating for the resulting focus shift.
Solution Approach 2:
The patent changes the physical parameter of air space distance between the prism and lens group according to the prism rotation angle. By varying this parameter through the focusing section, the system compensates for the focus shift that occurs during prism rotation, thereby maintaining image quality while achieving visual field direction changes.
2Device complexity
If the air space between the prism and lens group is fixed, then the structure is simple, but the depth of field becomes unstable when the visual field direction angle changes
Solution Approach 1:
The patent transitions from a fixed air space structure to a dynamic one where the focusing section adjusts the air space distance in response to prism rotation. This dynamic adjustment stabilizes the depth of field across different visual field directions, resolving the contradiction between structural simplicity and depth of field stability.
Solution Approach 2:
The focusing section acts as a feedback mechanism that detects the prism rotation angle and adjusts the air space accordingly. This feedback loop compensates for optical changes during rotation, maintaining stable depth of field while adding only minimal structural complexity through the focusing section mechanism.
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 enables the image pickup unit to maintain a favorable depth of field and prevent image rotation due to prism rotation, ensuring high-quality imaging across varying visual field directions.
Implementation Method 1
a front group FG which includes a prism P1, P2, and P3 which can be rotated for changing a visual field direction
Implementation Method 2
a rear group RG which includes a lens group LNS and an image pickup element 15
Data Source
AI summary
There is provided an image pickup unit which is capable of achieving a focused image of a favorable depth of field while changing a visual field direction of observation.An image pickup unit, comprises a front group which includes a prism that can be rotated for changing a visual field direction, and a rear group which includes a lens group and an image pickup element, wherein the image pickup unit includes a prism rotating section which rotates the prism for changing the visual field direction, and a focusing section which does not change a focused range, as an angle of visual field direction with respect to a longitudinal direction of the image pickup unit becomes smaller than a specific angle, and which moves the focused range toward a near-point side, as an angle of visual field direction with respect to the longitudinal direction of the image pickup unit becomes larger than the specific angle, in accordance with a rotation of the prism, and the focusing section, in a case in which the specific angle is not smaller than 30°, moves the focused range toward the near-point side.