Autofocus Testing Device Using Pre-positioned Targets
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Solution Overview
Problem
Existing autofocus testing devices for camera modules are inefficient due to the manual or mechanical repositioning of test members, which results in low operational efficiency and inconvenient testing processes.
Innovation Solution
An autofocus testing device and method that fixes at least two test members at different positions on an axis, using a voice coil motor to adjust the lens focus, capturing images, and recording driving currents when sharpness reaches a preset threshold, generating a correspondence table for quick focus adjustment in subsequent use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual or mechanical repositioning of test members is used, then device complexity is low, but productivity is low due to repeated repositioning operations
Solution Approach 1:
The patent pre-arranges multiple test members at different distances from the camera module before testing begins. This preliminary positioning eliminates the need for repeated repositioning operations during testing, thereby improving productivity without requiring complex dynamic adjustment mechanisms.
Solution Approach 2:
The patent uses multiple identical test members (such as cards with patterns) placed at different distances to represent different object distances. These copies allow the system to test multiple scenarios simultaneously without physically moving the test target, thus improving efficiency while keeping the device structure simple.
2Measurement precision
If multiple test members are repositioned for each test, then measurement precision can be maintained, but loss of time increases due to repeated repositioning operations
Solution Approach 1:
The test members are pre-positioned at multiple predetermined distances from the camera module before the testing sequence starts. This allows the autofocus system to immediately test different focus distances without time-consuming repositioning operations, maintaining measurement precision while significantly reducing test time.
Solution Approach 2:
The patent combines multiple testing scenarios (different object distances) into a single static arrangement of test members. By merging these scenarios spatially rather than temporally, the system can evaluate multiple focus distances in one test sequence without repeated setup operations, thus reducing time loss while preserving accuracy.
3Productivity
If manual operation is used for focus testing, then device complexity is minimal, but productivity is low and operation is inconvenient
Solution Approach 1:
The patent enables the autofocus system to automatically test itself by capturing images of pre-positioned test members and evaluating focus status without manual intervention. The system self-evaluates sharpness and determines focus accuracy, thereby improving productivity and ease of operation while keeping the device structure relatively simple.
Solution Approach 2:
The patent incorporates a feedback mechanism where the captured images are automatically evaluated for sharpness, and the focus status is determined based on this evaluation. This automated feedback loop eliminates manual assessment, improves testing throughput, and simplifies operation while maintaining measurement precision through objective image quality analysis.
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
The solution significantly improves test efficiency by automating the focus testing process, reducing test time and cost, while ensuring accurate data collection and quick focus adjustment for camera modules.
Implementation Method 1
using a voice coil motor to adjust the lens focus
Data Source
AI summary
A method for testing an autofocus function of a camera module fixes a camera module and at least two test members sequentially spaced at different positions on an axis pointing straight away from the camera. The camera module is controlled to focus and capture images of each test member and record driving currents of the camera module to achieve those focuses at those distances. When a sharpness of image of a test member reaches a preset threshold value a correspondence table between the driving currents and object distances is generated. An autofocus testing device is further provided.