Endoscope Optical Splitting for Depth of Field
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Solution Overview
Problem
Existing endoscope technologies face challenges in increasing the depth of field without enlarging the apparatus size, and methods to enhance resolving power often result in poor focus regions and increased noise.
Innovation Solution
An endoscope design incorporating an objective optical system with an optical-path splitting part that splits the subject image into two focused images, captured simultaneously by an imaging device, and a blocking part that cuts out abutting portions of these images, ensuring the condition A+B > C+D is met, allowing for enhanced depth of field while reducing device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple imaging devices are provided to form subject images that are focused differently, then the depth of field is increased, but the size of the imaging apparatus is increased
Solution Approach 1:
The imaging device's imaging surface is segmented into two distinct light-receiving regions that capture optical images with different optical path lengths. This segmentation allows the system to obtain multiple focused images (different depth planes) using a single imaging device, thereby increasing the depth of field without requiring multiple separate imaging devices or increasing the overall apparatus size.
2Measurement precision
If two subject images that are split by an optical-path splitting element and focused differently are formed in one imaging device, then the resolving power is enhanced, but a region in which a good focus cannot be achieved is created between the individual depths of field
Solution Approach 1:
Different regions of the imaging surface are assigned different optical path lengths, creating local quality variations. The first light-receiving region has a first optical path length optimized for one depth plane, while the second light-receiving region has a second optical path length optimized for another depth plane. This local differentiation allows each region to capture sharp images at its optimized depth, enhancing overall resolving power across different focal planes without creating unfocused regions between depth planes.
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 effectively increases the depth of field without increasing the apparatus size, while maintaining image quality and reducing the size of the imaging device, by ensuring the optical images do not overlap and are brought close enough to satisfy the conditional expression.
Implementation Method 1
an optical-path splitting part for splitting the subject image into two optical images having different optical path lengths
Implementation Method 2
two optical images which are arranged on an imaging surface and which are focused differently
Implementation Method 3
an imaging device that acquires two images by capturing the two optical images
Data Source
AI summary
An endoscope includes an objective optical system at a distal end of an inserted portion to acquire a subject image; a part that splits the subject image into two optical images focused differently; an imaging device that acquires two images by simultaneously capturing the optical images arranged on an imaging surface; and a part for cutting out at least abutting portions of the optical images on the imaging device, wherein A+B>C+D, where A is half the maximum length of light-receiving regions for the optical images at the imaging surface; where TW is an entry angle at the imaging surface when A is at the maximum image height and d is an optical-path-length difference between the optical images, B=d×tan TW; C is half the length of the light-receiving regions in a direction of the optical images arranged on the imaging surface; and D is a distance between the two light-receiving regions.