Imaging Pixel With Segmented Photoelectric Units for Ranging and Depth of Field
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Solution Overview
Problem
Imaging devices used in on-vehicle cameras face a challenge in achieving both high ranging performance and deep depth of field, as these requirements are often conflicting and difficult to satisfy simultaneously.
Innovation Solution
The imaging device incorporates a plurality of pixels with three photoelectric conversion units, each with a unique color filter and microlens configuration, allowing for separate signal readout and improved sensitivity, enabling high ranging accuracy and deep depth of field through the use of color filters with different transmittance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the aperture is opened to increase light intake for high ranging performance, then the ranging sensitivity is improved, but the depth of field becomes shallow
Solution Approach 1:
The imaging device segments the pixel structure into multiple photoelectric conversion units (first, second, and third units) within each pixel, allowing separate signal readout for ranging and imaging functions. This segmentation enables independent optimization of ranging sensitivity and depth of field without mutual interference.
Solution Approach 2:
Different color filters with different transmittance characteristics are applied to different photoelectric conversion units within the same pixel. The first and third color filters have higher transmittance for ranging signals, while the second color filter is optimized for imaging signals, creating local quality differences that resolve the contradiction between ranging performance and depth of field.
2Reliability
If the aperture is stopped down to increase depth of field, then the focus range is extended, but the ranging sensitivity decreases
Solution Approach 1:
The pixel is segmented into multiple photoelectric conversion units that can independently process light. By reading out signals from specific units (first and third units) that are optimized for ranging with higher transmittance color filters, the device maintains high ranging sensitivity even when the aperture is stopped down for increased depth of field.
Solution Approach 2:
The first and third color filters are designed with higher transmittance specifically for the ranging photoelectric conversion units, while the second color filter serves the imaging unit. This local quality differentiation allows the system to maintain ranging sensitivity across various aperture settings while achieving deep depth of field.
3Measurement precision
If color filters with high transmittance are used to improve ranging sensitivity, then the ranging performance is enhanced, but the color accuracy for imaging may be compromised
Solution Approach 1:
The imaging device segments the color filter application by unit, with the first and third color filters having high transmittance for ranging units, while the second color filter maintains appropriate transmittance for imaging units. This segmentation allows each unit to be optimized for its specific function without compromising overall color accuracy.
Solution Approach 2:
Different transmittance characteristics are applied locally to different color filters based on their functional requirements. The first and third color filters have higher transmittance for ranging sensitivity, while the second color filter has optimized transmittance for color accuracy in imaging, resolving the contradiction through localized quality differentiation.
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 ranging accuracy and maintains a deep depth of field, even at open F-values, by optimizing the signal processing and aperture control, thus addressing the conflicting requirements of high sensitivity and wide focus range.
Implementation Method 1
a microlens that collects light into the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit
Implementation Method 2
a first color filter through which a light entering the first photoelectric conversion unit passes, a second color filter through which a light entering the second photoelectric conversion unit passes, and a third color filter through which a light entering the third photoelectric conversion unit passes
Implementation Method 3
each of the plurality of pixels includes a first photoelectric conversion unit, a second photoelectric conversion unit, and a third photoelectric conversion unit
Data Source
AI summary
A disclosed imaging device includes a plurality of pixels arranged over a plurality of rows and a plurality of columns. Each of the plurality of pixels includes a first photoelectric conversion unit, a second photoelectric conversion unit, a third photoelectric conversion unit, a microlens that collects light into the first photoelectric conversion unit, the second photoelectric conversion unit, and the third photoelectric conversion unit, a first color filter through which a light entering the first photoelectric conversion unit passes, a second color filter through which a light entering the second photoelectric conversion unit passes, and a third color filter through which a light entering the third photoelectric conversion unit passes. The first to third photoelectric conversion units are arranged in this order in a first direction, and transmittances of the first color filter and the third color filter are different from a transmittance of the second color filter.