Endoscope Lens Arrangement for Chief Ray Angle Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Endoscopes face limitations in image resolution due to the size constraints of high-resolution image sensors, which are often designed for consumer electronics and automotive applications, resulting in a steep chief ray angle that complicates the design of compact optical assemblies.
Innovation Solution
The integration of a lens assembly with negative power near the focal plane to steepen the chief ray angle, incorporating a micro-lens array with non-linearly progressive offsets and a plano-concave lens to match the chief ray angle required by advanced image sensors, allowing for higher resolution capabilities within the endoscope shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution image sensors from consumer electronics are used in endoscopes, then image resolution is improved, but the chief ray angle becomes too steep for compact optical assemblies
Solution Approach 1:
The patent modifies the chief ray angle parameter by introducing a lens assembly with negative optical power between the objective lens and image sensor. This negative power lens group adjusts the angular distribution of light rays, reducing the steepness of chief rays while maintaining the high resolution capability of consumer electronics sensors in compact endoscope configurations
2Ease of manufacture
If sensors designed for consumer electronics are used, then manufacturing cost is reduced, but the chief ray angle characteristic does not match compact endoscope optical requirements
Solution Approach 1:
The patent introduces a lens assembly with negative optical power as an intermediary component between the objective lens and the consumer electronics image sensor. This intermediary lens group adapts the optical characteristics, specifically adjusting the chief ray angle to match the requirements of compact endoscope optical assemblies while maintaining compatibility with mass-produced consumer electronics sensors
3Volume of moving object
If the distal end portion of the endoscope shaft is made smaller to accommodate high-resolution sensors, then sensor integration is improved, but image resolution capabilities are limited
Solution Approach 1:
The patent changes the optical parameters by incorporating a lens assembly with negative optical power that enables compact distal end design. This optical configuration allows high-resolution consumer electronics sensors to be integrated into smaller distal end portions while maintaining their full resolution capability by properly controlling the chief ray angle characteristics
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 solution enables the successful integration of high-resolution image sensors with steep chief ray angles, enhancing the image resolution capabilities of endoscopes while maintaining a compact design, effectively addressing the limitations of existing sensor designs.
Implementation Method 1
a second lens group having a negative optical power including a plano-concave lens, the plano-concave lens optically positioned between the objective lens or lens group and the image sensor, the negative optical power modifying a chief ray angle characteristic of the lens assembly
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Videoendoscope designs are provided including an objective and image sensor (216, 218), preferably in the distal region, the image sensor having a micro-lens array with micro-lens offsets designed for a designated chief ray angle. The scope further includes a lens group having negative optical power optically arranged adjacent to the image sensor (216, 218). The negative optical power serves to modify the chief ray angle characteristic of the lens group to more closely match that required by the image sensor (216, 218) and micro-lens array. Some designs include a non-linear distortion in the second lens group (108) to compensate for non-linearly varying offsets in the sensor micro-lenses (140). Various lens group designs and sensor arrangements are provided.