Stacked Image Sensor Layout for Independent Phase-Detection AF
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Solution Overview
Problem
Conventional auto-focusing methods in electronic cameras face issues with spurious signals and require sophisticated pixel interpolation processing or complex optical systems, especially when using dedicated pixels or sensors for focus detection.
Innovation Solution
A solid-state imaging device with a second image sensor having an organic photoelectric conversion film and a first image sensor stacked on the same semiconductor substrate, where the second image sensor is arranged in a specific color array and shares the same optical path, allowing for focus detection without the need for complex pixel interpolation or optical systems, using a phase-difference AF method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pixel for focus detection is arranged at some of the pixels for imaging of an image sensor, then focus detection can be performed, but a spurious signal of vertical stripe or horizontal stripe is generated requiring sophisticated pixel interpolation processing
Solution Approach 1:
The image sensor is divided into two distinct layers: a first image sensor for imaging and a second image sensor for focus detection. This segmentation allows each layer to perform its specific function independently, eliminating the need for complex pixel interpolation processing while maintaining focus detection capability.
Solution Approach 2:
The solution transitions from a two-dimensional arrangement of focus detection pixels within the imaging plane to a three-dimensional stacked configuration with separate imaging and focus detection layers. This dimensional change enables independent optimization of each sensor's function without the spurious signal problems of planar arrangements.
2Ease of operation
If a dedicated image sensor for focus detection is used, then focus detection can be performed independently, but a complicated optical system for dividing incoming light is required
Solution Approach 1:
The first image sensor and second image sensor are merged into a single stacked sensor module sharing common semiconductor substrate and optical path. This integration eliminates the need for complicated optical systems for light division, as both sensors receive light through the same optical path without requiring beam splitters or other complex optical components.
Solution Approach 2:
The stacked sensor module serves multiple functions: the first image sensor performs imaging while the second image sensor performs focus detection. Both functions are achieved within a single unified structure that shares the optical path, eliminating the need for separate dedicated optical systems.
3Adaptability or versatility
If the second image sensor is arranged in a specific color array as a color filter, then color information can be captured, but the structure becomes more complex
Solution Approach 1:
The second image sensor serves dual purposes: it acts as both a color filter array for capturing color information and as a focus detection sensor. This multi-functionality eliminates the need for separate color filter structures while maintaining color capture capability, thereby reducing overall structural complexity.
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 high-speed auto-focusing independently of imaging pixels, eliminating the need for sophisticated interpolation processing and complex optical systems, while efficiently utilizing incoming light and maintaining image quality.
Implementation Method 1
a second image sensor 103 having an organic photoelectric conversion film
Data Source
AI summary
A solid-state imaging device includes a second image sensor having an organic photoelectric conversion film transmitting a specific light, and a first image sensor which is stacked in layers on a same semiconductor substrate as that of the second image sensor and which receives the specific light having transmitted the second image sensor, in which a pixel for focus detection is provided in the second image sensor or the first image sensor. Therefore, an AF method can be realized independently of a pixel for imaging.