Image Sensor Pupil Division for Accurate Manual Focus
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Solution Overview
Problem
Existing digital cameras without a reflex mirror face challenges in displaying accurate split images for manual focus, as they rely on contrast detection systems, which can lead to color shifts and inaccuracies in focus adjustment.
Innovation Solution
An image capture device with color filters and pixel groups that pupil-divide object images, generating split images without color shifts by displaying focusing confirmation images on a live-view display, allowing for accurate focus adjustment during manual focus operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a contrast detection system is used for manual focus in digital cameras without a reflex mirror, then the device complexity is reduced, but the measurement precision of focus state is insufficient leading to color shifts
Solution Approach 1:
The pixel array is divided into first pixel groups and second pixel groups that are spatially separated to receive light from different object regions. This segmentation enables the generation of a split image that provides accurate focus state information without requiring a reflex mirror, thus maintaining low device complexity while improving measurement precision.
Solution Approach 2:
Different regions of the image sensor are assigned different functions: the first pixel groups detect light from a first object region while the second pixel groups detect light from a second object region. This local differentiation allows the system to display focus state information in specific local areas of the displayed image, improving measurement precision without increasing overall device complexity.
2Measurement precision
If a mechanical aperture diaphragm shifting mechanism is used to create split images, then the measurement precision of focus state is improved, but the device complexity increases due to additional mechanical components
Solution Approach 1:
The patent replaces the mechanical aperture diaphragm shifting mechanism with an electronic solution using spatially separated pixel groups on the image sensor. Instead of mechanically moving components to create split images, the system uses electronically controlled light reception areas that are fixed in space, thereby maintaining high measurement precision while reducing device complexity.
Solution Approach 2:
The system creates multiple virtual images of the object on the image sensor by using pixel groups that receive light from different object regions. These copied images are then processed and displayed as a split image, providing accurate focus state information without requiring physical mechanical components to create the split effect.
3Ease of operation
If color information is added to split image without pupil division, then the ease of operation is improved, but the measurement precision deteriorates due to color shifts
Solution Approach 1:
The pixel array is segmented into first and second pixel groups that are spatially separated to receive light from different object regions. Each pixel group maintains its spatial relationship to the optical axis, allowing color information to be preserved while avoiding the color shifts that occur when color information is added without proper pupil division. This enables accurate focus measurement with full color capability.
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
Enables precise focus adjustment without color shifts, improving the accuracy of manual focus operations by generating split images that reflect the focus state accurately, even in digital cameras without reflex mirrors.
Implementation Method 1
an imaging lens, and an image capture element
Implementation Method 2
photoelectrically converting a first object image and a second object image
Data Source
AI summary
An image capture element includes phase difference pixel groups (first and second pixel groups) corresponding to first and second images with a phase difference according to a focus shift, includes a third pixel group corresponding to a normal third image, outputs a first image and a second image with Bayer arrays from the first and second pixel groups, and outputs a third image with the same color array as a RAW image from the third pixel group. A color split image is generated based on the first and second images acquired from the image capture element, a color image for display is generated based on the third image, and the color split image is synthesized with part of the generated color image for display to thereby display a live-view image in which the split image is synthesized.