Photodiode Array Wiring Segmentation for Temporal Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing photodiode arrays face challenges in improving temporal resolution due to increased time constants when adding capacitance, which can degrade performance.
Innovation Solution
The photodiode array design includes a semiconductor substrate with avalanche photodiodes, quenching resistors, and a unique wiring configuration where the resistance value per unit length of peripheral wiring is lower than relay wiring, allowing for reduced signal readout path resistance and improved temporal resolution, further enhanced by capacitors connected in parallel and strategically positioned electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitance is added in parallel to a quenching resistor to acuminated output waveform, then temporal resolution is improved, but time constant increases which degrades temporal resolution
Solution Approach 1:
The patent divides the wiring structure into multiple segments with different resistance characteristics: peripheral wiring connecting adjacent photodiodes has higher resistance to limit crosstalk, while relay wiring connecting to readout circuits has lower resistance to reduce time constant. This segmentation allows simultaneous optimization of both temporal resolution and time constant.
Solution Approach 2:
Different wiring regions are assigned different resistance values based on local requirements: peripheral wiring uses higher resistance for signal isolation, while relay wiring uses lower resistance for fast signal extraction. This local quality differentiation resolves the contradiction between waveform acumination and time constant reduction.
2Measurement precision
If peripheral wiring with low resistance is used to reduce signal readout path resistance, then temporal resolution improves, but crosstalk between adjacent photodiodes increases
Solution Approach 1:
The wiring is segmented into peripheral wiring for inter-photodiode connections and relay wiring for readout connections. Peripheral wiring has higher resistance to prevent crosstalk, while relay wiring has lower resistance for fast signal extraction, resolving the contradiction between temporal resolution and crosstalk.
Solution Approach 2:
The peripheral wiring acts as an intermediary with controlled high resistance between adjacent photodiodes, allowing signal isolation while the relay wiring provides a low-resistance path to readout circuits. This intermediary structure prevents direct low-resistance coupling that would cause crosstalk.
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 significantly improves temporal resolution by decreasing time constants and enabling higher signal transmission efficiency.
Implementation Method 1
a plurality of avalanche photodiodes which are operated in the Geiger mode
Implementation Method 2
a plurality of avalanche photodiodes (APDs) which are operated in the Geiger mode
Implementation Method 3
capacitors which are respectively connected in parallel to the respective quenching resistors
Implementation Method 4
the time constants are increased by a capacitor and a resistor, which may degrade temporal resolution
Data Source
Figure 1
Figure 2
Figure 3
AI summary
This photodiode array 10 includes quenching resistors 7 which are connected in series to respective avalanche photodiodes APDs, a peripheral wiring WL which surrounds a region in which the plurality of avalanche photodiodes APDs are formed, and a plurality of relay wirings 8 which are electrically connected to the peripheral wiring WL, so as to respectively connect at least two places of the peripheral wiring WL. One of an anode and a cathode of each avalanche photodiode APD is electrically connected to any one of the relay wirings 8 via the quenching resistor 7, and the other of the anode and the cathode of each avalanche photodiode APD is electrically connected to another electrode 6 provided on a semiconductor substrate.