Image Sensor Pixel Structure for Dynamic Range and Saturation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image pickup apparatuses using solid-state image sensing devices struggle to faithfully reproduce subject images due to unnatural image results from combining low and high sensitive light reception cells, which leads to issues like white splattering and difficulty in correcting saturation problems.
Innovation Solution
An image pickup apparatus with a solid-state image sensing device featuring multiple types of photoelectric conversion elements for different wave ranges, including visible light and infrared, generates monochrome and color image data, and combines contour information to produce record image data, ensuring faithful reproduction by adjusting exposure conditions and applying appropriate voltage to prevent signal saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If low sensitive light reception cell and high sensitive light reception cell are partially combined into one image, then wide dynamic range is achieved, but unnatural image results occur due to S/N ratio differences and time-space differences
Solution Approach 1:
The image sensor is divided into multiple independent pixel types (first photoelectric conversion pixels for visible light, second photoelectric conversion pixels for infrared light, and third photoelectric conversion pixels for other wave ranges). Each pixel type captures specific wavelength information independently, allowing selective combination based on illumination conditions rather than arbitrary mixing of all pixel outputs.
Solution Approach 2:
Different regions of the image are processed differently based on local illumination characteristics. The image processing apparatus determines appropriate pixel combinations and processing methods for different areas individually, applying local quality adjustments to maintain natural image appearance while achieving wide dynamic range where needed.
2Manufacturing precision
If image quality degradation area is corrected by replacing with corresponding area from other image, then white splattering and black batter are reduced, but correction becomes difficult when output is saturated
Solution Approach 1:
Multiple images at different exposure levels are captured in advance before saturation occurs. The image processing apparatus stores these pre-acquired images and selectively uses appropriate exposure data during processing, performing correction actions before saturation becomes a problem rather than attempting correction after saturation occurs.
Solution Approach 2:
The system changes exposure parameters by capturing images at multiple different exposure levels simultaneously. This allows the processing apparatus to select optimal exposure data for different image regions, enabling effective correction of saturation issues through parameter variation rather than attempting to correct saturated data.
3Reliability
If multiple types of photoelectric conversion elements are used for different wave ranges, then faithful subject image reproduction is achieved, but device complexity increases
Solution Approach 1:
The image sensor integrates multiple photoelectric conversion elements within a single pixel structure, where each pixel can function as different types of photoelectric conversion pixels based on the wavelength of incident light. This multi-functionality allows the device to capture visible light, infrared light, and other wave ranges using the same physical structure, reducing overall device complexity.
Solution Approach 2:
Different photoelectric conversion elements are nested within the same pixel structure, with the first photoelectric conversion pixels, second photoelectric conversion pixels, and third photoelectric conversion pixels all occupying the same spatial location. This nesting allows multiple functions to coexist in a compact arrangement, achieving wide spectral coverage without proportionally increasing device size or 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
The apparatus effectively reproduces subject images with improved dynamic range and reduced white splattering, maintaining image quality even under high illumination conditions by combining color and contour data, and providing high-resolution infrared data.
Implementation Method 1
a photoelectric conversion film that is formed above a semiconductor substrate for absorbing light in a specific wave range and generating a charge responsive thereto
Implementation Method 2
photoelectric conversion elements for detecting light in different wave ranges, of visible light, and absorbs light in a wave range different from the wave ranges detected in the at least three types of photoelectric conversion elements and generates a charge responsive to the absorbed light
Data Source
AI summary
An image pickup apparatus includes: a solid-state image sensing device that includes a plurality of pixels, each of the pixels including: a photoelectric conversion film; and a photoelectric conversion element that is formed in the semiconductor substrate below the photoelectric conversion film, are made up of at least three types of photoelectric conversion elements for detecting light in different wave ranges, of visible light, and absorbs light in a wave range different from the wave ranges detected in the at least three types of photoelectric conversion elements and generates a charge responsive to the absorbed light, the image pickup apparatus further including: a monochrome image data generation unit; a color image data generation unit; and a record image data generation unit.