Photoelectric Conversion Device Shared Time Counter Circuit
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Solution Overview
Problem
The existing photoelectric conversion apparatuses face an increase in circuit size due to the provision of separate photon counters and time counters for each pixel, which is inefficient and costly in terms of space and resources.
Innovation Solution
A photoelectric conversion apparatus is designed with a shared time counter among groups of pixels, where photon counters are provided for each pixel, and a selection circuit switches the connection of photon counters to the time counter when a threshold value is reached, allowing for efficient measurement of time taken for saturation and reducing circuit size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate photon counters and time counters are provided for each pixel, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple time counters into a single shared time counter that is共用 among multiple pixels. The selection circuit switches the connection between the shared time counter and different photon counters based on which pixel's photon counter has reached the threshold value first. This merging approach maintains the ability to measure time for each pixel while significantly reducing the total number of time counters needed, thereby reducing circuit complexity.
Solution Approach 2:
The shared time counter is designed to serve multiple functions by being connected to multiple photon counters through the selection circuit. Instead of having a dedicated time counter for each pixel, one time counter performs the time measurement function for multiple pixels sequentially, achieving multi-functionality and reducing overall device complexity.
2Measurement precision
If separate measurement circuits are provided for each pixel, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
By merging multiple time counters into a single shared resource, the patent reduces the total component count needed for manufacturing. The selection circuit enables this shared time counter to be efficiently allocated to multiple pixels, maintaining measurement precision while reducing manufacturing costs through economies of scale and reduced component requirements.
3Device complexity
If a shared time counter is used among multiple pixels, then device complexity is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent implements preliminary action by having each photon counter independently count photons and determine when its own threshold value is reached. The selection circuit is designed to switch connections based on which pixel reaches its threshold first, ensuring that the time measurement starts and stops correctly for each pixel even though the time counter is shared. This preliminary preparation of switching logic maintains measurement precision.
Solution Approach 2:
The selection circuit acts as an intermediary between the shared time counter and multiple photon counters. It manages the switching connections based on threshold reach events, ensuring that the time counter measures the correct time interval for each pixel without interference from other pixels. This intermediary mechanism preserves measurement precision while enabling resource sharing.
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 allows for accurate photon measurement while significantly reducing circuit size by sharing the time counter among multiple pixels, enabling precise brightness information acquisition and efficient signal processing.
Implementation Method 1
a photoelectric conversion circuit configured to output a signal corresponding to photon incidence
Data Source
AI summary
A photoelectric conversion apparatus includes a pixel including a photoelectric conversion circuit configured to output a signal corresponding to photon incidence. The photoelectric conversion apparatus further includes a first measurement circuit, a second measurement circuit, a selection circuit, and an output circuit. The first measurement circuit is configured to measure the signal output from the pixel. The second measurement circuit is configured to measure a time from when the first measurement circuit starts measuring the signal to when a measured value of the first measurement circuit reaches a first threshold value. The selection circuit is configured to switch a first measurement circuit to be connected to the second measurement circuit among a plurality of the first measurement circuits. The output circuit is configured to output a value of the measured time of the second measurement circuit.