Pixel circuit, driving method thereof, array substrate and display device

An array substrate, comprising a plurality of pixel circuits, wherein each pixel circuit of the plurality of pixel circuits comprises:

• a signal inputting sub-circuit, a signal reading sub-circuit, and a photosensitive element;
• wherein the signal inputting sub-circuit is coupled to a signal inputting terminal, an inputting control terminal, and a first terminal of the photosensitive element, and is configured to:
• under control of the inputting control terminal, turn on coupling between the signal inputting terminal and the first terminal of the photosensitive element in a signal writing period, and turn off the coupling between the signal inputting terminal and the first terminal of the photosensitive element in an exposure period and a signal reading period;
• wherein the signal reading sub-circuit is coupled to the first terminal of the photosensitive element, a reading control terminal, and a signal reading terminal, and is configured to:
• under control of the reading control terminal, turn off coupling between the first terminal of the photosensitive element and the signal reading terminal in the signal writing period and the exposure period, and turn on the coupling between the first terminal of the photosensitive element and the signal reading terminal in the signal reading period;
• and
• wherein a second terminal of the photosensitive element is coupled to a common electrode signal inputting terminal;
• wherein the signal reading sub-circuit comprises:
• a signal receiving module, a signal amplifying module, and a signal outputting module;
• wherein the signal receiving module is coupled to the first terminal of the photosensitive element, the reading control terminal, and an input terminal of the signal amplifying module, and is configured to:
• under the control of the reading control terminal, turn off the coupling between the first terminal of the photosensitive element and the input terminal of the signal amplifying module in the signal writing period and the exposure period, and turn on the coupling between the first terminal of the photosensitive element and the input terminal of the signal amplifying module in the signal reading period;
• and wherein the signal outputting module is coupled to an output terminal of the signal amplifying module, the reading control terminal, and the signal reading terminal, and is configured to:
• under the control of the reading control terminal, turn off the coupling between the output terminal of the signal amplifying module and the signal reading terminal in the signal writing period and the exposure period, and turn on the coupling between the output terminal of the signal amplifying module and the signal reading terminal in the signal reading period;
• wherein each pixel circuit of the plurality of pixel circuits further comprises at least one of the following:
• a first noise reduction sub-circuit, coupled to a noise reduction control terminal, the input terminal of the signal amplifying module, and a first level signal inputting terminal, and configured to:
• under control of the noise reduction control terminal, turn on coupling between the input terminal of the signal amplifying module and the first level signal inputting terminal in the signal writing period and the exposure period, and turn off the coupling between the input terminal of the signal amplifying module and the first level signal inputting terminal in the signal reading period;
• or,
• a second noise reduction sub-circuit, coupled to the noise reduction control terminal, the output terminal of the signal amplifying module and the first level signal inputting terminal, and configured to:
• under control of the noise reduction control terminal, turn on coupling between the output terminal of the signal amplifying module and the first level signal inputting terminal in the signal writing period and the exposure period, and turn off the coupling between the output terminal of the signal amplifying module and the first level signal inputting terminal in the signal reading period.

A pixel circuit, comprising:

• a signal inputting sub-circuit, a signal reading sub-circuit, and a photosensitive element;
• wherein the signal inputting sub-circuit is coupled to a signal inputting terminal, an inputting control terminal, and a first terminal of the photosensitive element, and is configured to:
• under control of the inputting control terminal, turn on coupling between the signal inputting terminal and the first terminal of the photosensitive element in a signal writing period, and turn off the coupling between the signal inputting terminal and the first terminal of the photosensitive element in an exposure period and a signal reading period;
• wherein the signal reading sub-circuit is coupled to the first terminal of the photosensitive element, a reading control terminal, and a signal reading terminal, and is configured to:
• under control of the reading control terminal, turn off coupling between the first terminal of the photosensitive element and the signal reading terminal in the signal writing period and the exposure period, and turn on the coupling between the first terminal of the photosensitive element and the signal reading terminal in the signal reading period;
• and
• wherein a second terminal of the photosensitive element is coupled to a common electrode signal inputting terminal;
• wherein the signal reading sub-circuit comprises:
• a signal receiving module, a signal amplifying module, and a signal outputting module;
• wherein the signal receiving module is coupled to the first terminal of the photosensitive element, the reading control terminal, and an input terminal of the signal amplifying module, and is configured to:
• under the control of the reading control terminal, turn off the coupling between the first terminal of the photosensitive element and the input terminal of the signal amplifying module in the signal writing period and the exposure period, and turn on the coupling between the first terminal of the photosensitive element and the input terminal of the signal amplifying module in the signal reading period;
• and wherein the signal outputting module is coupled to an output terminal of the signal amplifying module, the reading control terminal, and the signal reading terminal, and is configured to:
• under the control of the reading control terminal, turn off the coupling between the output terminal of the signal amplifying module and the signal reading terminal in the signal writing period and the exposure period, and turn on the coupling between the output terminal of the signal amplifying module and the signal reading terminal in the signal reading period;
• wherein the signal amplifying module comprises N transistors, a first electrode of each of the N transistors is coupled to a boost signal inputting terminal, and N is a positive integer greater than or equal to 1;
• wherein a gate electrode of a first transistor of the N transistors serves as the input terminal of the signal amplifying module, and a second electrode of an N-th transistor of the N transistors serves as the output terminal of the signal amplifying module, and among the N transistors, a gate electrode of an X-th transistor is coupled to a second electrode of an (X−1)-th transistor, where 1<X≤N;
• and wherein, when N is greater than 1, a width-to-length ratio of a channel of the first transistor to a width-to-length ratio of a channel of the N-th transistor increase successively.