Asymmetric Focus Detection Pixels for Image Pickup Accuracy
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Solution Overview
Problem
Conventional image pickup apparatuses face challenges in accurately calculating the focus shift due to unequal light amounts incident on focus detection pixels, leading to decreased focus adjustment accuracy.
Innovation Solution
The apparatus employs asymmetrical arrangement of light receiving elements and adjusts the micro lens position to optimize light distribution, ensuring efficient light reception and improved focus detection even at low or high light levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light receiving elements are arranged symmetrically for focus detection, then the structure is simple and manufacturing is easy, but the focus detection accuracy decreases when light amount is low or excessive
Solution Approach 1:
The patent applies asymmetry by arranging the first and second light receiving elements at different positions relative to the micro lens optical axis. Specifically, the first light receiving element is positioned at a first distance from the optical axis while the second light receiving element is positioned at a second distance, where these distances are intentionally made different to create asymmetric light reception characteristics. This asymmetric arrangement enables accurate focus detection across varying light conditions by optimizing the spatial distribution of light reception areas.
2Device complexity
If light receiving elements are positioned to receive equal light amounts, then the calculation is simplified, but focus detection precision deteriorates in low-light or high-light conditions
Solution Approach 1:
The patent applies local quality by giving different light reception characteristics to different regions of the focus detection pixel. The first light receiving element and second light receiving element are positioned at different distances from the micro lens optical axis, creating localized variations in light reception efficiency. This allows each element to optimize its performance for specific light conditions, with the first element potentially optimized for one lighting scenario and the second for another, thereby improving overall focus detection precision across varying light environments.
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 focus adjustment accuracy by efficiently utilizing light across the focus detection pixels, maintaining precision in both low-light and high-light conditions.
Implementation Method 1
a micro lens 311 and a light receiving element 314 having a light receiving surface on which an optical image is formed by the micro lens 311 are provided in each pixel
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A solid-state image pickup device includes a lens, a first light receiving element, a second light receiving element, and an element separation area. The first light receiving element is configured to receive light from the lens. The second light receiving element is configured to receive light from the lens. The element separation area is between the first light receiving element and the second light receiving element. The lens has an optical axis, which is offset from a center of the element separation area.