Imaging Device Light Blocking Portion for Phase Difference Detection
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Solution Overview
Problem
Imaging devices face challenges in maintaining consistent phase difference detection characteristics across different image heights due to vignetting, which affects the accuracy of focus adjustment in imaging apparatuses.
Innovation Solution
The imaging device incorporates a micro lens, a light sensing element, and a light blocking portion that performs pupil division, with the light blocking portion positioned such that the image forming point and the end portion on the entrance side become distant from each other according to variations in image height, ensuring consistent centroid positions and phase difference detection characteristics across all image heights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the exit pupil is equally divided into two in each phase difference detection pixel, then phase difference detection can be performed with high accuracy, but phase difference detection characteristics of on-axis and off-axis pixels become different due to vignetting
Solution Approach 1:
The patent applies local quality by setting different light blocking portion positions for on-axis and off-axis phase difference detection pixels. Specifically, for off-axis pixels, the light blocking portion is positioned such that the image forming point and the end portion on the entrance side become distant from each other according to variation in image height, compensating for vignetting effects locally at each pixel position while maintaining overall system performance
Solution Approach 2:
The patent changes the positional parameter of the light blocking portion based on image height. By adjusting the distance between the image forming point and the end portion of the light blocking portion on the entrance side according to image height variations, the system maintains consistent phase difference detection characteristics across different field positions
2Ease of operation
If a light blocking mask is positioned to equally divide the exit pupil, then phase difference detection is simplified, but vignetting causes inconsistent detection characteristics across different image heights
Solution Approach 1:
The patent implements local quality by applying different light blocking portion positioning strategies for on-axis and off-axis pixels. For off-axis pixels, the light blocking portion is specifically positioned to account for vignetting, ensuring that phase difference detection accuracy is maintained across the entire image field while keeping the operation simple
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 enhances the accuracy and consistency of phase difference detection, improving the overall focusing determination process by maintaining constant phase difference detection characteristics regardless of image height, thereby enhancing the imaging device's performance.
Implementation Method 1
a micro lens that collects light from a subject
Implementation Method 2
a light sensing element that generates a signal for performing focusing determination through phase difference detection by sensing subject light collected by the micro lens
Data Source
AI summary
An imaging device includes a micro lens that collects light from a subject, a light sensing element that generates a signal for performing focusing determination through phase difference detection by sensing subject light collected by the micro lens, and a light blocking portion that is disposed between the micro lens and the light sensing element and performs pupil division for the subject light by blocking a part of the subject light, wherein the light blocking portion is set such that a position of an image forming point of subject light passing through the micro lens and a position of an end portion of the light blocking portion on an entrance side become distant from each other according to a variation in image height.