Lens Barrel Eccentricity Measurement Using Transparent Index Plates
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Solution Overview
Problem
Existing methods fail to accurately measure shift and tilt eccentricity amounts in lens frames within a lens barrel, making it difficult to determine if eccentricity is due to the lenses, lens frames, or the assembly process, which hinders modifications to mold shapes and adhesive application in optical devices.
Innovation Solution
The method involves using transparent flat plate members with indexes in each lens cell, where illumination or parallel light is used to measure positional displacement for shift eccentricity and angle displacement for tilt eccentricity, utilizing an image pickup apparatus and processor to obtain accurate eccentricity amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional adjustment methods are used to measure eccentricity in lens barrels, then the measurement process is simple, but the measurement precision is insufficient to accurately determine the source of eccentricity
Solution Approach 1:
A transparent plate with a mark is introduced as an intermediary reference object placed on each lens frame. This plate serves as a mediator between the lens frame and the imaging device, enabling precise measurement of the lens frame's position and orientation by comparing the mark's position to the lens frame's reference features, thereby achieving high measurement precision without directly measuring the lens itself
Solution Approach 2:
The patent replaces conventional mechanical measurement methods with an optical imaging system. Instead of using mechanical gauges or contact-based measurement tools, the system uses an imaging device to capture images of the marks on transparent plates, and processing means to calculate eccentricity from these images, thereby achieving non-contact, high-precision measurement
2Difficulty of detecting and measuring
If no reference marks are used in lens cells, then the assembly process is simpler, but the ability to detect and measure eccentricity is insufficient
Solution Approach 1:
Marks are pre-formed on transparent plates before assembly. The transparent plates with marks are prepared in advance and then placed on the lens frames during assembly, allowing the measurement reference to be established before the final assembly is complete, thereby enabling eccentricity detection without complicating the assembly process
Solution Approach 2:
The patent uses visual contrast through marks on transparent plates. The marks are formed with sufficient contrast against the transparent plate background, enabling easy detection and imaging. This visual differentiation method simplifies the detection process by providing clear, distinguishable reference points without adding complex measurement fixtures
3Measurement precision
If multiple measurement points are taken to determine eccentricity source, then the accuracy in identifying eccentricity source improves, but the measurement time increases
Solution Approach 1:
The patent combines multiple measurement capabilities into a single imaging operation. By capturing an image that contains marks from multiple lens frames simultaneously and processing this single image to extract position and orientation information for each frame, the system achieves comprehensive eccentricity measurement without requiring multiple separate measurement steps, thereby reducing measurement time while maintaining precision
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 allows for precise measurement of shift and tilt eccentricity, enabling accurate feedback for mold modifications and adhesive application, improving the assembly and performance of optical devices.
Implementation Method 1
emitting illumination light to the flat plate members, obtaining pieces of information related to positions of the indexes formed on the flat plate members
Implementation Method 2
emitting parallel light from a position facing a flat plate member arranged at an outermost position among the flat plate members, in such a manner that the parallel light is transmitted through the respective flat plate members
Implementation Method 3
obtaining an angle information obtainment related to an angle of reflected light of the parallel light from each of the flat plate members
Data Source
AI summary
According to one aspect, an eccentricity amount obtainment method is a method of obtaining shift eccentricity amounts of lens frames through in a lens barrel that includes the plurality of lens frames having lens cells, the eccentricity amount obtainment method including arranging, in each of the lens cells, a flat plate member on which an index is formed and which has optical transparency and arranging the lens frames in the lens barrel in a prescribed order so as to assemble an assembly, a emitting illumination light to the flat plate members, obtaining pieces of information related to positions of the indexes formed on the flat plate members, and obtaining, as the shift eccentricity amounts of the lens frames, the positional displacement amounts with respect to the indexes formed on the flat plate members with respect to an arbitrary position.