Image sensor

Abstract

The invention provides an image sensor, and the image sensor comprises at least two identical sub-pixel units; each sub-pixel unit comprises a charge exposure transfer structure and a capacitance feedback transconductance amplifier, and each capacitance feedback transconductance amplifier comprises an integrating capacitor, an initialization transistor and a source follower. Two ends of the blocking capacitor are respectively coupled with the charge exposure transfer structure and a grid electrode of the source follower, and a source electrode of the source follower is connected with a reference voltage; two ends of the integrating capacitor are respectively coupled with a grid electrode and a drain electrode of the source electrode follower and are used for carrying out integral amplification on a signal to be output by the source electrode follower, and a source electrode and a drain electrode of the initialization transistor are respectively coupled with two ends of the integrating capacitor and are used for resetting the integrating capacitor. According to the invention, the pixel is divided into a plurality of sub-pixel units for segmented driving, and the CTIA is configured in each sub-pixel unit, so that the parasitic capacitance of the input end of the CTIA is reduced, the noise of the CTIA is reduced, the signal-to-noise ratio of the image sensor is improved, and the imaging effect is improved.

Description

technical field [0001] The invention relates to the technical field of CMOS image sensors, in particular to a CMOS image sensor based on a CTIA pixel structure. Background technique [0002] At present, spectral imaging is widely used in mineral resource exploration, biomedical identification, food detection, atmospheric research and other fields. The spectrometer mainly includes a light source system, a spectroscopic imaging system and a receiving device. The atoms of the elements emit spectral lines under the action of the excitation light source. The spectral lines are separated by the spectroscopic imaging system to form a spectrum. Each element has its own characteristic spectral lines. The intensity of the spectral lines represents the content of the elements in the sample. Each spectrum of the image sensor is photoelectrically converted by the photosensitive array of the image sensor, then analog-to-digital converted by the readout circuit, and finally the data is pr...

AI Technical Summary

Problems solved by technology

[0005] Because the CTIA is located on one side of the pixel array, the column bus is too long, the parasitic capacitance at the input end of the CTIA is too large, and the noise of the CTIA is too large, which will reduce the signal-to-noise ratio of the CMOS image sensor and affect the imaging effect.

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