Demodulation Pixel for High Dynamic Range Imaging
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Solution Overview
Problem
Existing image sensors struggle to generate images with a higher dynamic range effectively from recording two original images without time artifacts and complex control mechanisms.
Innovation Solution
An image sensor with a matrix of demodulation pixels, featuring a separation device that separates charge carriers into two streams in alternating time periods, allowing for simultaneous storage and optimal charge current flow, and a readout device that converts stored charge carriers into electrical signals without time offsets, using a 2-tap demodulation pixel structure with doped substrates and modulation gates for efficient exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If charge carriers are separated sequentially in one period, then charge current flows optimally and exposure completes quickly, but time artifacts occur due to time offset between the two original images
Solution Approach 1:
The patent applies periodic action by using alternating time periods (first time period and second time period) within each pixel cycle to separate charge carriers into different storage devices. This periodic separation allows both original images to be captured and stored simultaneously without time offset, eliminating time artifacts while maintaining efficient charge current flow through the structured temporal pattern
2Manufacturing precision
If complex control mechanisms are used to generate images with higher dynamic range, then image quality improves, but device complexity increases
Solution Approach 1:
The patent segments the pixel structure into distinct functional components: a conversion area for generating charge carriers, a separation device with first and second storage devices for temporal separation, and a readout device. This segmentation allows each component to perform its function independently and efficiently, achieving high dynamic range imaging through simple, dedicated structures rather than complex control mechanisms
3Loss of time
If sequential charge carrier separation is used, then exposure time is reduced, but time offsets between images occur causing time artifacts
Solution Approach 1:
The patent resolves the time conflict by introducing a spatial dimension - using separate storage devices (first storage device and second storage device) positioned at different locations within the pixel to store charge carriers from different time periods. This spatial separation of temporal data allows simultaneous capture of both original images without time offset, eliminating time artifacts while maintaining fast exposure
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 solution enables the generation of images with higher dynamic range without time artifacts, simplifies control, and allows for quick exposure completion, achieving effective image processing and reduced time offsets.
Implementation Method 1
each with a conversion area for generating charge carriers from the received radiation
Implementation Method 2
The separator has a drift gate on top of the substrate for attracting charge carriers from the conversion region into the separator
Implementation Method 3
The separation device has two modulation gates on the upper side of the substrate, in particular at opposite points of the drift gate, for alternately directing and separating the charge carriers
Data Source
Figure 1
AI summary
The image sensor (10) according to the invention is an image sensor with a matrix of pixels for generating a resulting image with a higher dynamic range from the acquisition of 2 original images, wherein the pixels of the image sensor are designed as demodulation pixels, each with a conversion area (20) for generating charge carriers from the received radiation (90), a separation device (30) for temporally separating the generated charge carriers into 2 charge carrier streams, a storage device (40) with 2 storage elements for separately storing the charge carriers of the 2 charge carrier streams, and a readout device (50) for converting the stored charge carriers into electrical signals, wherein the separation device is configured to perform the separation of the charge carriers generated in one period in 2 different time periods.