Low-temperature polycrystalline silicon flat panel detector pixel circuit and flat panel detection method

A flat-panel detector and low-temperature polysilicon technology, applied in the field of flat-panel detection, can solve problems such as threshold voltage drift, electrical signal loss, etc., and achieve the effects of reducing off-state leakage current, suppressing electrical signal loss, and high field-effect mobility

Active Publication Date: 2020-04-03
SHANGHAI IRAY TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a low-temperature polysilicon flat panel detector pixel circuit and a flat panel detection method, which are used to solve the problem that the output current change value of the APS pixel unit circuit in the prior art is affected by the source follower. The impact of threshold voltage drift, and the leakage current when the reset switch is off state leads to the loss of electrical signals and other issues

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  • Low-temperature polycrystalline silicon flat panel detector pixel circuit and flat panel detection method
  • Low-temperature polycrystalline silicon flat panel detector pixel circuit and flat panel detection method
  • Low-temperature polycrystalline silicon flat panel detector pixel circuit and flat panel detection method

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Embodiment 1

[0051] Such as image 3 As shown, this embodiment provides a low temperature polysilicon flat panel detector pixel circuit 2, the low temperature polysilicon flat panel detector pixel circuit 2 includes: a first reset switch T RST1 , storage capacitor C ST , transmission gate T X , photodiode PD, second reset switch T RST2 , compensation switch T CMP , source follower T SF and selector switch T SEL .

[0052] Wherein, the first reset switch T RST1 The first terminal is connected to the reset signal V RST , the control terminal is connected to the first control signal V GRST , the second terminal is connected to the storage capacitor C ST the first plate of

[0053] The transmission gate T X The first terminal of the storage capacitor C is connected ST The first plate, the control terminal is connected to the second control signal V CMP , the second terminal is connected to the cathode of the photodiode PD, and the anode of the photodiode PD is connected to the bia...

Embodiment 2

[0064] Such as Figure 4 ~ Figure 8 As shown, this embodiment provides a flat-panel detection method, which is implemented based on the pixel circuit of the low-temperature polysilicon flat-panel detector in Embodiment 1. The flat-panel detection method includes:

[0065] 1) Reset stage: close the selection switch T SEL , turn on the first reset switch T RST1 , transmission gate T X , the second reset switch T RST2 , compensation switch T CMP and source follower T SF ;Storage capacitor C ST The potential on the first plate is reset to a positive level, and the potential on the second plate is reset to a negative level; the photodiode PD is in a reverse bias state.

[0066] Specifically, such as Figure 4 and Figure 5 As shown, in this embodiment, the third control signal V SEL set high, the selector switch T SEL off; the first control signal V GRST and the second control signal V CMP set low, the first reset switch T RST1 , the transmission gate T X , the second...

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Abstract

The invention provides a low-temperature polycrystalline silicon flat panel detector pixel circuit and a flat panel detection method. The low-temperature polycrystalline silicon flat panel detector pixel circuit comprises a first reset switch and a transmission gate which are sequentially connected between a reset signal and a cathode of a photosensitive diode in series, and an anode of the photosensitive diode being connected with bias voltage; a second reset switch, a source follower and a selection switch which are sequentially connected between the power supply signal output ends in series; a compensation switch connected between the source electrode and the grid electrode of the source electrode follower; and a storage capacitor connected between the drain electrode of the first resetswitch and the grid electrode of the source follower. The first reset switch and the control end of the first reset switch are connected with a first control signal, and the transmission gate and thecontrol end of the compensation switch are connected with a second control signal. The control end of the selection switch is connected with a third control signal. Internal compensation is carried out on threshold voltage drift of a source follower in the circuit, off-state leakage current of the first reset switch is reduced, and high-frame-rate, high-sensitivity and low-dose dynamic flat paneldetection can be realized.

Description

technical field [0001] The invention relates to the field of flat-panel detection, in particular to a low-temperature polysilicon flat-panel detector pixel circuit and a flat-panel detection method. Background technique [0002] Flat panel detectors are generally used in many fields such as medical X-ray radiation imaging, security inspection and security, and industrial non-destructive testing. Generally speaking, flat panel detectors can be divided into direct type and indirect type. Direct flat panel detectors can directly convert X-rays into electrical signals, and can realize direct conversion of X-ray energy. The typical representative is amorphous selenium (a-Se) flat panel detectors, which combine amorphous selenium materials and thin film transistors (TFT) technology has high spatial resolution, but it needs to apply a high voltage on the amorphous selenium film, which may cause components to be easily burned out and fail, and the system stability is poor. The ind...

Claims

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Application Information

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IPC IPC(8): G09G3/32G01T1/24G01T1/161
CPCG01T1/161G01T1/24G01T1/247G09G3/32
Inventor 解海艇金利波朱翀煜
Owner SHANGHAI IRAY TECH
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