Endoscope Image Pickup Unit Phase Reference Pixel Design
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Solution Overview
Problem
Endoscopes face signal delay issues due to varying transmission cable lengths and electronic component performance, which necessitates video phase adjustment, but existing solutions either increase the size of the insertion portion or require a timing generator, complicating the image pickup unit design.
Innovation Solution
The image pickup unit incorporates a phase reference pixel region outside the effective pixel region, allowing light to reach a phase reference pixel for video phase adjustment, enabling compact design without a timing generator, and reducing the size of the image pickup optical system member and peripheral circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a timing generator is provided on the image pickup device side to perform video phase adjustment, then video phase adjustment can be performed to synchronize the image pickup device with the camera control unit, but the size of the electronic circuit around the image pickup device increases, which results in an increase in the diameter of the insertion portion of the endoscope
Solution Approach 1:
The patent extracts the phase reference function from a separate timing generator and integrates it directly into the image pickup device's pixel array. By defining a phase reference pixel region within the pixel forming region, the invention eliminates the need for external timing generator circuits, thereby reducing the electronic circuit size and insertion portion diameter while maintaining video phase adjustment capability
Solution Approach 2:
The image pickup device's pixel array is made multi-functional by incorporating both the effective pixel region for image capture and the phase reference pixel region for timing synchronization. This universal design allows the same device to perform both imaging and phase adjustment functions without requiring separate dedicated components
2Ease of operation
If the transmission cable length is increased to accommodate the image pickup device outside the insertion portion, then the camera control unit can be positioned outside for reduced size, but signal delay occurs due to variation in length and electrical performances of incorporated electronic components
Solution Approach 1:
The patent implements a feedback mechanism by using the phase reference pixel region to generate signals that enable the camera control unit to adjust sampling timings based on actual signal conditions. This feedback loop compensates for signal delay variations caused by cable length and component performance variations, ensuring stable and reliable signal transmission over long distances
3Reliability
If video phase adjustment is performed to synchronize the image pickup device with the camera control unit, then signal delay can be compensated, but the size of the electronic circuit and transmission cable must be increased to reduce tolerances
Solution Approach 1:
The invention extracts the essential phase reference function from complex external timing generator circuits and implements it directly within the image pickup device's pixel array. This extraction eliminates the need for additional electronic circuits and reduces overall device complexity while maintaining accurate video phase adjustment capability
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 allows for effective video phase adjustment without increasing the size of the image pickup unit, maintaining a compact form factor and facilitating easier insertion while reducing the size of the distal end portion of the endoscope.
Implementation Method 1
the objective optical system member is configured such that an intersection point at which an optical axis of the objective optical system member intersects with the effective pixel region is arranged shifted to a position closer to the phase reference pixel region with respect to a center of the effective pixel region so as to allow light transmitted through the objective optical system member to reach the phase reference pixel region
Data Source
AI summary
In this invention, an image pickup unit for endoscope including an image pickup device includes, in an optical black region of the image pickup device, a phase reference pixel region in which a pixel that outputs a signal capable of being used for phase adjustment of the video by receiving light is disposed, and an optical axis of an objective optical system member having an image circle which is narrower than an effective pixel region of the image pickup device is arranged at a position closer to the phase reference pixel region with respect to a center of the effective pixel region such that light transmitted through the objective optical system member can reach the phase reference pixel region.