TOF Sensor Demodulation Pixels Sharing Common Aperture
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Solution Overview
Problem
Existing TOF distance sensors have limitations in sensitivity and resolution due to the design of individual demodulation pixels, which restricts their ability to effectively capture distance information and generate high-quality 3D images.
Innovation Solution
The TOF distance sensor employs a pixel matrix with demodulation pixels that share a common aperture and evaluation region, utilizing a semiconductor substrate with a thinned conversion region and a separating device comprising drift, modulation, storage, and transfer gates to enhance sensitivity and resolution, allowing for smaller pixel dimensions and improved charge carrier management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual demodulation pixels are used with separate apertures and evaluation regions, then each pixel can independently process charge carriers, but the sensitivity and resolution of the TOF distance sensor are limited
Solution Approach 1:
Multiple demodulation pixels share a common aperture and a common evaluation region, merging previously separate components. This allows charge carriers generated in the conversion region to be collectively evaluated, increasing sensitivity and resolution while reducing the overall number of separate evaluation regions needed in the pixel matrix
Solution Approach 2:
The patent transitions from front-side reception to rear-side reception of radiation by the demodulation pixels. This dimensional change in the reception approach allows for improved charge carrier management and enables the common aperture and evaluation region configuration to function effectively
2Productivity
If pixel dimensions are reduced to increase pixel matrix density, then more pixels can be packed into the sensor, but sensitivity decreases due to smaller aperture area
Solution Approach 1:
By merging multiple pixels to share a common aperture, the effective aperture area per pixel group is increased, compensating for the reduction in individual pixel dimensions. This allows higher pixel matrix density while maintaining or improving sensitivity through the collective aperture area
Solution Approach 2:
The pixel matrix is segmented into groups where multiple demodulation pixels share common resources (aperture and evaluation region). This segmentation strategy allows smaller individual pixel dimensions while maintaining overall system sensitivity through the combined aperture area of each group
3Measurement precision
If the conversion region is thinned to improve charge carrier generation efficiency, then photoelectric conversion is enhanced, but charge carrier management and separation become more difficult
Solution Approach 1:
A drift gate is introduced as an intermediary component between the thinned conversion region and the evaluation region. This drift gate facilitates the efficient transport and management of charge carriers through the thinned substrate, overcoming the challenges of charge carrier control in a reduced-thickness conversion region
4Measurement precision
If rear-side reception of radiation is implemented in demodulation pixels, then charge carrier generation is improved, but the separating device must be redesigned to handle charge carriers from the opposite side
Solution Approach 1:
The demodulation pixels are inverted to receive radiation from the rear side rather than the front side. This inversion changes the direction of charge carrier generation and requires the separating device to be configured accordingly, with the conversion region positioned to receive radiation from the side facing away from the separating device and evaluation region
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 design enhances the sensitivity and effectiveness of the TOF distance sensor, enabling more precise distance measurement and improved image generation, particularly in 3D imaging, by efficiently managing charge carriers and maintaining spatial information.
Implementation Method 1
a conversion region for generating charge carriers from the received radiation
Implementation Method 2
the separating device comprises a drift gate for attracting the charge carriers from the conversion region into the separating region
Data Source
AI summary
TOF distance sensor for capturing the distance to an object by receiving radiation reflected by the object, said radiation emanating from a radiation source modulated by a modulation frequency, comprising a pixel matrix for recording a pixel image. The pixel matrix consists of demodulation pixels which are designed for rear-side reception of the radiation. The demodulation pixels comprise a conversion region for generating charge carriers from the received radiation, and a separating device for separating the charge carriers in accordance with the modulation frequency, and also a stop for partitioning-off the conversion region from the separating device in relation to the charge carriers, and also an aperture for passing the charge carriers from the conversion region into the separating device. The TOF distance sensor is embodied in such a way that in each case at least two demodulation pixels form a common aperture.