TOF Depth Imaging Timing Control for Stable Pixel Phase
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Solution Overview
Problem
Conventional depth imaging devices using the indirect time of flight (TOF) method face accuracy issues due to fluctuations in the electric potential of power supply and ground, which affect the operation timing of pixels, leading to reduced depth measurement precision.
Innovation Solution
A depth imaging device with a pixel array, control signal output circuit, and delay adjustment circuits that maintain constant phase differences between control and drive signals, ensuring stable operation timing despite fluctuations in power supply and ground potential, and a package design with symmetric electrical paths to minimize timing discrepancies between pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional depth imaging devices use indirect TOF method with pixel arrays and gate electrodes, then depth measurement function is achieved, but measurement precision deteriorates due to fluctuations in power supply and ground electric potential affecting operation timing
Solution Approach 1:
The patent applies equipotentiality by providing separate power supply wirings and ground wirings for each driver circuit, ensuring that each pixel operates at a stable electric potential independent of fluctuations in other pixels. This isolates each pixel's operation timing from potential noise and voltage drops in shared power networks, thereby maintaining consistent timing across all pixels despite power supply variations.
Solution Approach 2:
The patent segments the power supply and ground networks by providing dedicated power supply wirings and ground wirings for each driver circuit rather than using shared common networks. This segmentation prevents timing fluctuations in one pixel from affecting other pixels and maintains stable operation timing for depth measurement across the entire pixel array.
2Measurement precision
If common power supply and ground wirings are used for multiple drivers, then device complexity is reduced, but measurement precision deteriorates due to timing fluctuations caused by electric potential variations
Solution Approach 1:
The patent segments the power supply and ground networks by providing dedicated power supply wirings and ground wirings for each driver circuit rather than using shared common networks. This segmentation prevents timing fluctuations in one pixel from affecting other pixels and maintains stable operation timing for depth measurement across the entire pixel array.
Solution Approach 2:
The patent implements local quality by tailoring the power supply and ground connections to each specific driver circuit's requirements. Each driver receives dedicated power and ground connections optimized for its location and operational characteristics, ensuring locally stable timing for each pixel's depth measurement function.
3Measurement precision
If delay adjustment circuits are added to maintain constant phase differences, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the delay time of control signals in delay adjustment circuits before they reach the gate electrodes. This preliminary timing adjustment compensates for path length differences and ensures that all pixels operate in synchronization, maintaining constant phase differences between control signals and drive signals for accurate depth measurement.
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 solution enables accurate depth measurement by maintaining consistent operation timing across pixels, thereby enhancing the precision of depth measurement even under conditions of power supply and ground potential fluctuations.
Implementation Method 1
each of the plurality of pixels including a photoelectric converter that converts received light into charge
Data Source
AI summary
A depth imaging device includes: a plurality of delay adjustment circuits that adjust a delay time of each of a plurality of control signals that control a plurality of gate electrodes of a plurality of pixels and output a plurality of delayed control signals with adjusted delay times; and a plurality of drivers that receive input of the plurality of delayed control signals and output a plurality of drive signals that drive the plurality of gate electrodes of the plurality of pixels.