Solid State Imaging Device Temperature Sensor Noise Reduction
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Solution Overview
Problem
Solid state imaging devices experience noise due to temperature sensors, which is not effectively addressed in existing technologies, as they do not provide adequate solutions for reducing noise caused by the temperature sensors themselves.
Innovation Solution
Incorporating a current control circuit that manages the current supplied to the temperature sensor, allowing a predetermined current in one period and reducing or stopping it in another, to minimize light emission and subsequent noise during image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is provided in the solid state imaging device to correct image signals based on temperature, then temperature-based image correction is improved, but noise is generated due to light emission from the temperature sensor
Solution Approach 1:
The temperature sensor operates periodically rather than continuously. A control circuit supplies current to the temperature sensor only during specific periods (e.g., during vertical blanking periods between frame readings), allowing temperature measurement while minimizing light emission noise during active image capture. This periodic operation resolves the contradiction by enabling temperature correction functionality while suppressing noise generation.
Solution Approach 2:
Temperature measurement is performed in advance during blanking periods before the next frame of image data is captured. By obtaining temperature data preliminarily and using it for subsequent image correction, the system achieves accurate temperature-based correction without the temperature sensor being active during image capture, thereby eliminating noise contamination.
2Measurement precision
If current is continuously supplied to the temperature sensor for accurate temperature measurement, then measurement precision is improved, but light emission and noise increase
Solution Approach 1:
Current supply to the temperature sensor is made periodic rather than continuous. The control circuit activates the temperature sensor only during specific time windows (such as vertical blanking periods) when no image data is being captured, thereby achieving necessary temperature measurements while completely eliminating light emission noise during active imaging periods.
Solution Approach 2:
The temperature measurement function is extracted from the continuous operation mode and separated into discrete periodic measurement intervals. By taking out the temperature sensing action from continuous operation and confining it to specific blanking periods, the system achieves measurement precision without the harmful continuous light emission that would contaminate image data.
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 approach significantly reduces noise in the output signal by controlling the current to the temperature sensor, thereby improving image quality by minimizing the impact of temperature sensor-induced noise.
Implementation Method 1
a temperature sensor configured to output a signal in accordance with a temperature
Implementation Method 2
each of the pixels having a photoelectric conversion element
Data Source
AI summary
Provided is an imaging device including a pixel array including pixels; a readout circuit that reads out signals from the pixels; a temperature sensor that outputs a signal in accordance with a temperature; and a current control circuit that controls a current supplied to the temperature sensor. The current control circuit performs control in a first period such that a predetermined current is supplied to the temperature sensor, and performs control in a second period such that a current supplied to the temperature sensor becomes smaller than the predetermined current or stops. The first period is set in a first blanking period between a process in which the first readout circuit reads out one frame of signals output from the pixels and a process in which the first readout circuit reads out next one frame of signals output from the pixels.