Camera Module Testing Opaque Mask Impulse Response
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Solution Overview
Problem
Current camera module testing procedures are tedious, time-consuming, and prone to errors due to the need for precise alignment and multiple test targets to measure optical performance, which complicates the assessment of lens sharpness, vignetting, and lens tilt.
Innovation Solution
A method involving an opaque mask with predetermined-sized holes is illuminated, allowing the camera module to form a two-dimensional impulse response image, which is used to determine optical characteristics such as focus uniformity, vignetting, and geometrical distortion, enabling a single target and fully automated testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple test targets and careful alignment are used to measure optical performance, then measurement precision is improved, but device complexity and time consumption increase
Solution Approach 1:
The patent combines multiple test targets into a single integrated target that includes both a resolution chart and a reflective target. This single target enables simultaneous measurement of multiple optical parameters (lens sharpness, vignetting, lens tilt) without requiring separate targets or repeated alignment procedures, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The single test target is designed to serve multiple functions: it contains patterns for measuring lens sharpness, reflective surfaces for measuring vignetting and lens tilt, and geometric features for alignment reference. This multi-functional target eliminates the need for multiple specialized targets and procedures, simplifying the overall testing system while preserving comprehensive optical performance assessment.
2Measurement precision
If multiple test targets and careful alignment are used to measure optical performance, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent combines multiple test targets into a single integrated target that includes both a resolution chart and a reflective target. This single target enables simultaneous measurement of multiple optical parameters (lens sharpness, vignetting, lens tilt) without requiring separate targets or repeated alignment procedures, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The test target is pre-designed with all necessary measurement features (resolution patterns, reflective surfaces, alignment markers) integrated in a single configuration. This preliminary preparation eliminates the need for multiple setup steps and repeated alignment during testing, significantly reducing testing duration while maintaining comprehensive measurement capability.
3Measurement precision
If ad-hoc testing procedure with multiple targets is used, then measurement comprehensiveness is improved, but ease of operation deteriorates
Solution Approach 1:
The patent combines multiple test targets into a single integrated target that includes both a resolution chart and a reflective target. This single target enables simultaneous measurement of multiple optical parameters (lens sharpness, vignetting, lens tilt) without requiring separate targets or repeated alignment procedures, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The single test target is designed to serve multiple functions: it contains patterns for measuring lens sharpness, reflective surfaces for measuring vignetting and lens tilt, and geometric features for alignment reference. This multi-functional target eliminates the need for multiple specialized targets and procedures, simplifying the overall testing system while preserving comprehensive optical performance assessment.
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 simplifies image analysis and reduces alignment precision, allowing for efficient and automated determination of camera module optical characteristics, improving testing efficiency and accuracy.
Implementation Method 1
An opaque mask having a number of holes may be illuminated from the rear of the opaque mask. Each of the holes may have a predetermined size such that a camera module is unable to resolve some of the holes, which then become point sources of illumination for the camera module.
Implementation Method 2
Each of the holes may have a predetermined size such that a camera module is unable to resolve some of the holes, which then become point sources of illumination for the camera module
Implementation Method 3
A two-dimensional impulse response image of the illuminated opaque mask may be formed using the camera module. The two-dimensional impulse response image of the illuminated opaque mask may include a point spread function of the camera module for each hole that is a point source of illumination.
Data Source
AI summary
In a particular embodiment, a method is disclosed that includes illuminating an opaque mask having a plurality of holes formed therein, each hole of the plurality of holes having a predetermined size. The method includes forming a two-dimensional impulse response image of the illuminated opaque mask using a camera module. The method further includes determining at least one optical characteristic of the camera module based on the two-dimensional impulse response image of the illuminated opaque mask.