TW201545150A - Sensing apparatus of display panel - Google Patents

Abstract

The sensing apparatus includes a sensor and a sampling amplifier. The sensor includes switches, capacitors and gain amplifiers. Second terminals of first and second switches respectively coupled to first and second terminals of third switch. First and second terminals of the first capacitor respectively coupled to a reference voltage and the second terminal of the first switch. Input terminals of the first and the second gain amplifiers respectively coupled to the second terminals of the first and the second switches, and output terminals of the first and the second gain amplifiers respectively coupled to the first and the second input terminals of the sampling amplifier. The first terminal of the second switch coupled to a common mode voltage. The first terminal of the first switch coupled to the pixel circuit via the data line of the display panel.

Description

Display panel sensing device

The present invention relates to an electronic device, and more particularly to a sensing device for a display panel.

1 is a circuit block diagram illustrating a conventional active matrix organic light emitting diode (AMOLED) display. The AMOLED display includes a gate driver 110, a source driver 120, and a display panel 130. The display panel 130 has a plurality of scan lines (gate lines, such as scan lines S_1 and scan lines S_2), a plurality of data lines (source lines, such as data lines D_1 and data lines D_2), and a plurality of pixel circuits (eg, pixel circuits) 131). The pixel circuit 131 has a switch 132, a current source transistor 133, and an organic LED (OLED) 134.

The gate driver 110 can sequentially scan different scan lines of the display panel 130 to allow the source driver 120 to write data voltages to the pixel circuits. Taking the pixel circuit 131 shown in FIG. 1 as an example, during the period in which the gate driver 110 turns the switch 132 through the scan line S_1, the source driver 120 can transmit the data voltage to the current source through the data line D_1 and the switch 132. The gate of the transistor 133. The gate voltage of the current source transistor 133 can determine the current I1 of the current source transistor 133. The current I1 flowing through the organic light-emitting diode 134 can determine the brightness of the organic light-emitting diode 134. The relationship between the gate-source voltage V _{GS of the} current source transistor 133 and the current I1 is I1=k(V _GS -Vt) ² , where the coefficient k is a real number and Vt represents the threshold voltage of the current source transistor 133 (threshold voltage) ). The threshold voltages of the current source transistors in different pixel circuits may differ from each other due to process drift or other factors. Differences/drifts in threshold voltage may result in Mura (uneven source) or other artifacts of the image. If the threshold voltage of the current source transistor 133 can be detected, the source driver 120 can adjust the data voltage written in the pixel circuit 131 to compensate for the drift of the threshold voltage.

The present invention provides a sensing device for a display panel that can sense a threshold voltage of a current source transistor in a pixel circuit of the display panel.

Embodiments of the present invention disclose a sensing device for a display panel. The sensing device includes a sensor and a sampling amplifier. The input end of the sensor is coupled to the pixel circuit via a data line of the display panel to sense a threshold voltage of the current source transistor in the pixel circuit during sensing. The first input end and the second input end of the sampling amplifier are respectively coupled to the first output end and the second output end of the sensor. The sensor includes a first switch, a second switch, a third switch, a first capacitor, a first gain amplifier, and a second gain amplifier. The first end of the first switch is coupled to the pixel circuit via a data line. The first end of the second switch is coupled to a common mode voltage. The first end and the second end of the third switch are respectively coupled to the second end of the first switch and the second end of the second switch end. The first end and the second end of the first capacitor are respectively coupled to the first reference voltage and the second end of the first switch. The input end of the first gain amplifier is coupled to the second end of the first switch, and the output end of the first gain amplifier is coupled to the first input end of the sampling amplifier as a first output end of the sensor. The input end of the second gain amplifier is coupled to the second end of the second switch, and the output end of the second gain amplifier is coupled to the second input of the sampling amplifier as a second output of the sensor.

Another embodiment of the present invention discloses a sensing device for a display panel. sense The measuring device includes a sensor and a sampling amplifier. The input end of the sensor is coupled to the pixel circuit via a data line of the display panel to sense a threshold voltage of the current source transistor in the pixel circuit during sensing. The first input end and the second input end of the sampling amplifier are respectively coupled to the first output end and the second output end of the sensor. The sampling amplifier includes a differential amplifier, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first switch, a second switch, a third switch, a fourth switch, a fifth switch, and a sixth switch. The first output end and the second output end of the differential amplifier are respectively coupled to the first output end and the second output end of the sampling amplifier. The first end and the second end of the first capacitor are respectively coupled to the first output end of the sensor and the first input end of the differential amplifier. The first end and the second end of the second capacitor are respectively coupled to the second output end of the sensor and the second input end of the differential amplifier. The first end of the third capacitor is coupled to the first input of the differential amplifier. The first end of the fourth capacitor is coupled to the second input of the differential amplifier. The first end and the second end of the first switch are respectively coupled to the first input end of the differential amplifier and the first output end of the differential amplifier. The first end and the second end of the second switch are respectively coupled to the second end of the third capacitor and the common mode voltage. The first end and the second end of the third switch are respectively coupled Connected to the second end of the third capacitor and the first output of the differential amplifier. The first end and the second end of the fourth switch are respectively coupled to the second input end of the differential amplifier and the second output end of the differential amplifier. The first end and the second end of the fifth switch are respectively coupled to the second end of the fourth capacitor and the common mode voltage. The first end and the second end of the sixth switch are respectively coupled to the second end of the fourth capacitor and the second output end of the differential amplifier.

Based on the above, an embodiment of the present invention provides a sensing device for a display panel, which can reduce an offset of an amplifying circuit in a sensor and/or a sampling amplifier. Therefore, the sensing device can accurately sense the threshold voltage of the current source transistor in the pixel circuit of the display panel.

The above described features and advantages of the invention will be apparent from the following description.

110, 210‧‧ ‧ gate driver

120, 220‧‧‧ source drive

130, 230‧‧‧ display panel

131, 231‧‧‧ pixel circuits

132, 232, 236, 237‧ ‧ switch

133‧‧‧current source transistor

134‧‧‧Organic Luminescent Diodes

200‧‧‧ display device

233‧‧‧current source transistor

234‧‧‧Lighting diode

235‧‧‧ storage capacitor

300‧‧‧Sensing device

310_1, 310_2, 310_n‧‧‧ sensors

320‧‧‧Sampling amplifier

330‧‧‧ Analog Digital Converter

410‧‧‧First Gain Amplifier

420‧‧‧second gain amplifier

510‧‧‧current mirror

511, 512‧‧‧ PMOS transistor

520‧‧‧Optoelectronics

530‧‧‧current source

710‧‧‧Differential Amplifier

B[K:1]‧‧‧ digital detection results

C1‧‧‧first capacitor

C2‧‧‧second capacitor

C3‧‧‧ third capacitor

C4‧‧‧fourth capacitor

C5‧‧‧ fifth capacitor

C6‧‧‧ sixth capacitor

C7‧‧‧ seventh capacitor

C8‧‧‧ eighth capacitor

D_1, D_2, D_n‧‧‧ data lines

g _m1 , g _m2 , M*g _m2 ‧‧‧ transduction

GND‧‧‧ Grounding voltage

I1, I2‧‧‧ current

I _IN ‧‧‧current of current source 530

M_1, M_2, M_m‧‧‧ mode lines

R _IN ‧‧‧ Internal resistance of the first gain amplifier 410

S_1, S_2, S_m‧‧‧ scan lines

SW1‧‧‧ first switch

SW2‧‧‧second switch

SW3‧‧‧ third switch

SW4‧‧‧fourth switch

SW5‧‧‧ fifth switch

SW6‧‧‧ sixth switch

SW7‧‧‧ seventh switch

SW8‧‧‧ eighth switch

SW9‧‧‧ninth switch

SW10‧‧‧ tenth switch

SW11‧‧‧ eleventh switch

VCM‧‧‧ Common mode voltage

VDD‧‧‧ system voltage

VI‧‧‧ input of the first gain amplifier 410

VIN_GA‧‧‧ second input of sampling amplifier 320

The first input of the VIP_GA‧‧ sampling amplifier 320

VO‧‧‧output of the first gain amplifier 410

The second output of the VON‧‧ sensor 310_n

VON_GA‧‧‧ second output of sampling amplifier 320

The first output of the VOP‧‧ sensor 310_n

VOP_GA‧‧‧ first output of sampling amplifier 320

1 is a circuit block diagram illustrating a conventional active organic light emitting diode display.

2 is a circuit diagram showing a display device in accordance with an embodiment of the invention.

3 is a circuit diagram illustrating a sensing device in accordance with an embodiment of the invention.

4 is a circuit diagram showing the sensor of FIG. 3 according to an embodiment of the invention.

FIG. 5 is a circuit diagram showing the gain amplifier of FIG. 4 according to an embodiment of the invention.

FIG. 6 is a circuit diagram showing the sensor of FIG. 3 according to another embodiment of the present invention.

FIG. 7 is a circuit diagram showing the sampling amplifier of FIG. 3 according to an embodiment of the invention.

"Coupling" used in the full text of this prospectus (including the scope of patent application) The term "接接" can refer to any direct or indirect means of attachment. For example, if the first device is described as being coupled to the second device, it should be construed that the first device can be directly connected to the second device, or the first device can be connected through other devices or some kind of connection means. Connected to the second device indirectly. In addition, wherever possible, the elements and/ Elements/components/steps that use the same reference numbers or use the same terms in different embodiments may refer to the related description.

2 is a circuit diagram illustrating a display device 200 in accordance with an embodiment of the invention. The display device 200 includes a gate driver 210, a source driver 220, and a display panel 230. The display panel 130 has a plurality of scan lines (or gate lines, such as scan lines S_1, S_2, ..., S_m), a plurality of data lines (or source lines, such as data lines D_1, D_2, ..., D_n), and A plurality of pixel circuits (eg, pixel circuit 231). The pixel circuit 231 has a switch 232, a current source transistor 233, a light emitting diode 234, a storage capacitor 235, a switch 236, and a switch 237. The light emitting diode 234 can be an organic light emitting diode (organic) LED, OLED) or other types of light-emitting diodes. Other pixel circuits in the display panel 130 can be analogized with reference to the related description of the pixel circuit 231.

During normal operation, the gate driver 210 can set the signals of the mode lines M_1, M_2, . . . , M_m to a first logic level (eg, a low logic level). When the signals of the mode lines M_1~M_m are at a low logic level, the switch 236 of each pixel circuit in the display panel 230 is turned off, and the switch 237 is turned on. During normal operation, the gate driver 210 can also scan the different scan lines S_1~S_m of the display panel 230 in order to allow the source driver 220 to write the data voltage through the data lines D_1~D_n into the pixel circuit. Taking the pixel circuit 231 shown in FIG. 2 as an example, during the period in which the gate driver 210 turns the switch 232 through the scan line S_m, the source driver 220 can transmit the data voltage to the current source through the data line D_n and the switch 232. The gate of the transistor 233. This data voltage can be stored in the storage capacitor 235. The gate voltage of the current source transistor 233 can determine the current I2 of the current source transistor 233. The current I2 flowing through the organic light-emitting diode 234 can determine the brightness of the organic light-emitting diode 234. The relationship between the gate-source voltage V _{GS of the} current source transistor 233 and the current I2 is I2=k(V _GS -Vt) ² , where the coefficient k is a real number and Vt represents the threshold voltage of the current source transistor 233 (threshold voltage) ).

During sensing, the gate driver 210 can set the signals of the mode lines M_1~M_m to a second logic level (eg, a high logic level). When the signals of the mode lines M_1~M_m are at a high logic level, the switch 236 of each pixel circuit in the display panel 230 will turn on, and the switch 237 will turn off. During sensing, the gate-source voltage V _{GS of the} current source transistor 233 can be pulled down to near 0V due to the conduction of the switch 236. During the sensing, the gate driver 210 can also scan the different scan lines S_1 S S_m of the display panel 230 in order to allow the sensing device 300 (described later) of the source driver 220 to pass through the data lines D_1~D_n. The threshold voltage of the current source transistor in different pixel circuits is measured. Taking the pixel circuit 231 shown in FIG. 2 as an example, during the period in which the gate driver 210 turns the switch 232 through the scan line S_m, the sensing device 300 inside the source driver 220 can be transmitted through the data line. D_n and switch 232 sense the threshold voltage of current source transistor 233 in pixel circuit 231. After the threshold voltage of the current source transistor 233 is sensed, the source driver 220 can adjust the data voltage to be written to the pixel circuit 231 to compensate for the drift of the threshold voltage.

FIG. 3 is a circuit diagram illustrating a sensing device 300 in accordance with an embodiment of the invention. Referring to FIGS. 2 and 3 , the sensing device 300 of the display panel 230 can be embedded in the source driver 220 . The sensing device 300 includes a sensor (such as the sensors 310_1, 310_2, ..., 310_n shown in FIG. 3), a sampling amplifier 320, and an analog-to-digital converter 330. The input ends of the sensors 310_1~310_n are coupled to the data lines D_1~D_n of the display panel 230 in a one-to-one manner. For example, the input end of the sensor 310_n is coupled to the pixel circuit 231 of the display panel 230 via the data line D_n of the display panel 230 to sense the threshold voltage of the current source transistor 233 in the pixel circuit 231 during sensing. And then output the sensed result to the input of the sampling amplifier 320. The first input terminal VIP_GA and the second input terminal VIN_GA of the sampling amplifier 320 are respectively coupled to the first output end and the second output end of the sensors 310_1~310_n, for example, coupled to the first output end VOP of the sensor 310_n. And the second output terminal VON. sampling The amplifier 320 can sample and amplify the outputs of the sensors 310_1~310_n, and correspondingly output the analog detection results to the input of the analog-to-digital converter 330. The analog digital converter 330 can convert the analog detection result into a digital detection result B[K:1]. Therefore, the source driver 220 can adjust the drift of the threshold voltage according to the digital detection result B[K:1] (or according to the analog detection result) correspondingly adjusting the data voltage to be written into the pixel circuit.

FIG. 4 is a circuit diagram showing the sensor 310_n of FIG. 3 according to an embodiment of the invention. Other sensors shown in FIG. 3 can be analogized with reference to the relevant description of the sensor 310_n. Referring to FIG. 2, FIG. 3 and FIG. 4, the sensor 310_n includes a first switch SW1, a second switch SW2, a third switch SW3, a first capacitor C1, a second capacitor C2, a first gain amplifier 410, and a second gain. Amplifier 420. The first end of the first switch SW1 is coupled to the pixel circuit (eg, the pixel circuit 231 or the like) of the display panel 230 via the data line D_n. The first end of the second switch SW2 is coupled to a common mode voltage VCM. The first end and the second end of the third switch SW3 are respectively coupled to the second end of the first switch SW1 and the second end of the second switch SW2.

The first end and the second end of the first capacitor C1 are respectively coupled to the first reference voltage VR1 and the second end of the first switch SW1. The first reference voltage VR1 may be a fixed voltage of any level, such as a system voltage VDD, a ground voltage GND, or other fixed voltage. The first end and the second end of the second capacitor C2 are respectively coupled to the second reference voltage VR2 and the second end of the second switch SW2. The second reference voltage VR2 can be a fixed voltage of any level, such as a system voltage VDD, a ground voltage GND, or Other fixed voltages. The first reference voltage VR1 may be the same or different from the second reference voltage VR2.

The input end of the first gain amplifier 410 is coupled to the second end of the first switch SW1. The output of the first gain amplifier 410 is coupled to the first input terminal VIP_GA of the sampling amplifier 320 as the first output terminal VOP of the sensor 310_n. The input end of the second gain amplifier 420 is coupled to the second end of the second switch SW2. The output of the second gain amplifier 420 is coupled to the second input terminal VIN_GA of the sampling amplifier 320 as the second output terminal VON of the sensor 310_n. The first gain amplifier 410 and the second gain amplifier 420 can be any type of amplification circuit. For example, in the present embodiment, the first gain amplifier 410 and the second gain amplifier 420 may be unit Gain amplifiers.

When the display panel 230 operates during the sensing period, during the first period (first phase) T1 of the sensing period, the first switch SW1 and the second switch SW2 are turned on, and the third switch SW3 is turned off. Therefore, in the first period T1, the output VOP (T1) of the first gain amplifier 410 = D_n + V _offset1 , and the output VON (T1) of the second gain amplifier 420 = VCM + V _offset2 . Wherein, V _offset1 represents the voltage offset of the first gain amplifier 410, and V _offset2 represents the voltage offset of the second gain amplifier 420. The sampling amplifier 320 can calculate VOP(T1) - VON(T1) = (D_n + V _offset1 ) - (VCM + V _offset2 ) in the first period T1. During the second period (second phase) T2 of the sensing period, the first switch SW1 and the second switch SW2 are turned off, and the third switch SW3 is turned on. Therefore, in the second period T2, the output VOP (T2) of the first gain amplifier 410 = V _reset + V _offset1 , and the output VON (T2) of the second gain amplifier 420 = V _reset + V _{offset 2} . Wherein V _reset represents the input terminal voltage of the first gain amplifier 410 and the second gain amplifier 420 when the third switch SW3 is turned on. The sampling amplifier 320 can calculate VOP(T2) - VON(T2) = V _offset1 - V _offset2 in the second period T2. The sampling amplifier 320 can calculate [VOP(T1)-VON(T1)]-[VOP(T2)-VON(T2)]=D_n-VCM. Therefore, the voltage offset of the first gain amplifier 410 and the second gain amplifier 420 can be eliminated.

The first gain amplifier 410 and the second gain amplifier 420 can be any type of amplification circuit. For example, FIG. 5 is a circuit diagram illustrating the first gain amplifier 410 of FIG. 4 in accordance with an embodiment of the present invention. Other gain amplifiers shown in FIG. 4 can be analogized with reference to the related description of the first gain amplifier 410. Referring to FIG. 5, the first gain amplifier includes a current mirror 510, a transistor 520, and a current source 530. In the present embodiment, the current mirror 510 includes a P-channel metal oxide semiconductor (PMOS) transistor 511 and a PMOS transistor 512. The gate of the PMOS transistor 511 is coupled to the drain of the PMOS transistor 511 and the gate of the PMOS transistor 512. The PMOS transistor 511 can provide the main current path of the current mirror 510, while the PMOS transistor 512 can provide the servant current path of the current mirror 510. In this embodiment, the channel aspect ratio of the PMOS transistor 512 may be M times the channel aspect ratio of the PMOS transistor 511. That is, if the transduction of the PMOS transistor 511 is g _m2 , the transduction of the PMOS transistor 512 is M*g _m2 .

The first end of the main current path of the current mirror 510 is coupled to the first end of the current path to the system voltage VDD, and the second end of the current path of the current mirror 510 is coupled to the output end of the first gain amplifier 410. . A control terminal (e.g., a gate) of the transistor 520 is coupled to the input terminal VI of the first gain amplifier 410. A first end (eg, a drain) of the transistor 520 is coupled to a second end of the main current path of the current mirror 510. One end of the current source 530 is coupled to the second end of the transistor 520 (eg, the source) and the second end of the current path of the current mirror 510. The other end of the current source 530 is coupled to the ground voltage GND. Assuming that the current of current source 530 is I _IN , then I _IN = g _m1 VI+ Where g _m1 represents the transduction of the transistor 520. Internal resistance of the first gain amplifier 410 . Therefore, the internal resistance R _{IN of the} first gain amplifier 410 can be effectively reduced.

FIG. 6 is a circuit diagram illustrating the sensor 310_n of FIG. 3 according to another embodiment of the present invention. Other sensors shown in FIG. 3 can be analogized with reference to the relevant description of the sensor 310_n. Referring to FIG. 2, FIG. 3 and FIG. 6, the sensor 310_n includes a first switch SW1, a second switch SW2, a third switch SW3, a fourth switch SW4, a fifth switch SW5, a first capacitor C1, and a second capacitor C2. a third capacitor C3, a fourth capacitor C4, a first gain amplifier 410, and a second gain amplifier 420. The embodiment shown in FIG. 6 can be analogized with reference to the related description of FIG. The first end of the first switch SW1 is coupled to the pixel circuit (eg, the pixel circuit 231 or the like) of the display panel 230 via the data line D_n. The first end of the second switch SW2 is coupled to the common mode voltage VCM. The first end and the second end of the third switch SW3 are respectively coupled to the second end of the first switch SW1 and the second end of the second switch SW2.

The first end and the second end of the first capacitor C1 are respectively coupled to the first reference voltage VR1 and the second end of the first switch SW1. The first end and the second end of the second capacitor C2 are respectively coupled to the second reference voltage VR2 and the second end of the second switch SW2. The first end and the second end of the third capacitor C3 are respectively coupled to the second end of the first switch SW1 and the input end of the first gain amplifier 410. The first end and the second end of the fourth capacitor C4 are respectively coupled to the second end of the second switch SW2 and the input end of the second gain amplifier 420. The first end and the second end of the fourth switch SW4 are respectively coupled to the input end of the first gain amplifier 410 and the bias voltage V _BIAS . The first end and the second end of the fifth switch SW5 are respectively coupled to the input end of the second gain amplifier 420 and the bias voltage V _BIAS . The output of the first gain amplifier 410 is coupled to the first input terminal VIP_GA of the sampling amplifier 320 as the first output terminal VOP of the sensor 310_n. The output of the second gain amplifier 420 is coupled to the second input terminal VIN_GA of the sampling amplifier 320 as the second output terminal VON of the sensor 310_n. In the present embodiment, the first gain amplifier 410 and the second gain amplifier 420 may be unit gain amplifiers. Embodiments of the first gain amplifier 410 and/or the second gain amplifier 420 can be analogized with reference to the related description of FIG.

When the display panel 230 is operated during the sensing period, the first switch SW1, the second switch SW2, the fourth switch SW4, and the fifth switch SW5 are turned on during the first period (first phase) T1 of the sensing period. The third switch SW3 is turned off. Therefore, in the first period T1, the output VOP (T1) of the first gain amplifier 410 = V _BIAS + V _offset1 , and the output VON (T1) of the second gain amplifier 420 = V _BIAS + V _{offset 2} . Wherein, V _offset1 represents the voltage offset of the first gain amplifier 410, and V _offset2 represents the voltage offset of the second gain amplifier 420. The sampling amplifier 320 may calculate VOP(T1) - VON(T1) = (V _BIAS + V _offset1 ) - (V _BIAS + V _offset2 ) = V _offset1 - V _offset2 in the first period T1. During the second period (second phase) T2 of the sensing period, the first switch SW1, the second switch SW2, the fourth switch SW4, and the fifth switch SW5 are turned off, and the third switch SW3 is turned on. Therefore, in the second period T2, the output VOP of the first gain amplifier 410 (T2) = V _BIAS + V _offset1 - And the output of the second gain amplifier 420 is VON(T2)=V _BIAS + . The sampling amplifier 320 can calculate VOP(T2) - VON(T2) = (V _offset1 - V _offset2 ) - (D_n - VCM) in the second period T2. The sampling amplifier 320 can calculate [VOP(T1)-VON(T1)]-[VOP(T2)-VON(T2)]=D_n-VCM. Thus, the voltage gain of the first amplifier 410 and the offset voltage V _offset1 second gain offset V _offset2 amplifier 420 can be eliminated.

FIG. 7 is a circuit diagram showing the sampling amplifier 320 of FIG. 3 in accordance with an embodiment of the invention. Referring to FIG. 2, FIG. 3 and FIG. 7, the sampling amplifier 320 includes a differential amplifier 710, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a sixth switch SW6, and a seventh switch SW7. The eighth switch SW8, the ninth switch SW9, the tenth switch SW10, and the eleventh switch SW11. The first output terminal (eg, the non-inverting output terminal) and the second output terminal (eg, the inverting output terminal) of the differential amplifier 710 are coupled to the first output terminal VOP_GA and the second output terminal VON_GA of the sampling amplifier 320, respectively. The first end of the fifth capacitor C5 serves as the first input terminal VIP_GA of the sampling amplifier 320 to be coupled to the first output end of the sensors 310_1~310_n. The second end of the fifth capacitor C5 is coupled to the first input end of the differential amplifier 710 (eg inverting input). The first end of the sixth capacitor C6 serves as the second input terminal VIN_GA of the sampling amplifier 320 to be coupled to the second output end of the sensors 310_1~310_n. The second end of the sixth capacitor C6 is coupled to the second input of the differential amplifier 710 (eg, a non-inverting input).

The first end of the seventh capacitor C7 is coupled to the first input end of the differential amplifier 710. The first end of the eighth capacitor C8 is coupled to the second input of the differential amplifier 710. The first end and the second end of the sixth switch SW6 are respectively coupled to the first input end of the differential amplifier 710 and the first output end of the differential amplifier. The first end and the second end of the seventh switch SW7 are respectively coupled to the second end of the seventh capacitor C7 and the common mode voltage VCM. The first end and the second end of the eighth switch SW8 are respectively coupled to the second end of the seventh capacitor C7 and the first output end of the differential amplifier 710. The first end and the second end of the ninth switch SW9 are respectively coupled to the second input end of the differential amplifier 710 and the second output end of the differential amplifier 710. The first end and the second end of the tenth switch SW10 are respectively coupled to the second end of the eighth capacitor C8 and the common mode voltage VCM. The first end and the second end of the eleventh switch SW11 are respectively coupled to the second end of the eighth capacitor C8 and the second output end of the differential amplifier 710. In this embodiment, the capacitance value of the fifth capacitor C5 is the same as the sixth capacitor C6, and the capacitance value of the seventh capacitor C7 is the same as the eighth capacitor C8.

When the display panel 230 is operated during the sensing period, the sixth switch SW6, the seventh switch SW7, the ninth switch SW9, and the tenth switch SW10 are turned on during the first period (first phase) T1 of the sensing period. The eighth switch SW8 and the eleventh switch SW11 are turned off. The charge of the fifth capacitor C5 and the seventh capacitor C7 in the first period T1 is -VCM], where V _offset represents the voltage offset of the differential amplifier 710 and A represents the gain value of the differential amplifier 710. In the second period (second phase) T2, the sixth switch SW6, the seventh switch SW7, the ninth switch SW9, and the tenth switch SW10 are turned off, and the eighth switch SW8 and the eleventh switch SW11 are turned on. The charge of the fifth capacitor C5 and the seventh capacitor C7 in the second period T2 is C5*[VIP_GA'-(VCM+ Where VIP_GA' represents the voltage at the first input of the differential amplifier 710 during the second period T2.

By arranging the equation Available . and so, . Therefore, the voltage offset _{Voffset of the} differential amplifier 710 can be lowered.

In summary, the sensing device 300 provided by the above embodiments can reduce the offset of the amplifying circuit in the sensors 310_1~310_n and/or the sampling amplifier 320. Accordingly, the sensing device 300 can accurately sense the threshold voltage of the current source transistor 233 in the pixel circuit of the display panel 230.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

300‧‧‧Sensing device

310_1, 310_2, 310_n‧‧‧ sensors

320‧‧‧Sampling amplifier

330‧‧‧ Analog Digital Converter

B[K:1]‧‧‧ digital detection results

D_1, D_2, D_n‧‧‧ data lines

VIN_GA‧‧‧ second input of sampling amplifier 320

The first input of the VIP_GA‧‧ sampling amplifier 320

The second output of the VON‧‧ sensor 310_n

VON_GA‧‧‧ second output of sampling amplifier 320

The first output of the VOP‧‧ sensor 310_n

VOP_GA‧‧‧ first output of sampling amplifier 320

Claims (17)

A sensing device for a display panel, comprising: a sensor, wherein an input end is coupled to a pixel circuit of the display panel via a data line of the display panel to sense a pixel circuit during a sensing period a threshold voltage of a current source transistor; and a sampling amplifier, a first input end and a second input end are respectively coupled to a first output end and a second output end of the sensor; The sensor includes: a first switch having a first end coupled to the pixel circuit via the data line; a second switch having a first end coupled to a common mode voltage; and a third switch having a first end The second end is coupled to the second end of the first switch and the second end of the second switch; a first capacitor, the first end and the second end are respectively coupled to a first reference voltage and the second capacitor a second end of the first switch; a first gain amplifier having an input coupled to the second end of the first switch, and an output of the first gain amplifier as the first output of the sensor And coupled to the first input of the sampling amplifier; and a second increase An amplifier having an input coupled to the second end of the second switch, and an output of the second gain amplifier coupled to the second input of the sampling amplifier as the second output of the sense amplifier end. The sensing device of the display panel of claim 1, wherein the first switch and the second switch are turned on during a first period, and the third switch is For the second period, the first switch and the second switch are turned off, and the third switch is turned on. The sensing device of the display panel of claim 1, wherein the first gain amplifier and the second gain amplifier are both unit gain amplifiers. The sensing device of the display panel of claim 1, wherein the sensor further comprises: a second capacitor, wherein the first end and the second end are respectively coupled to a second reference voltage and the first The second end of the second switch. The sensing device of the display panel of claim 1, wherein the sensor further comprises: a third capacitor coupled to the input end of the first gain amplifier and the second end of the first switch a fourth capacitor coupled between the input end of the second gain amplifier and the second end of the second switch; a fourth switch having a first end and a second end coupled to the first An input end of a gain amplifier and a bias voltage; and a fifth switch, the first end and the second end of which are respectively coupled to the input end of the second gain amplifier and the bias voltage. The sensing device of the display panel of claim 5, wherein the first switch, the second switch, the fourth switch, and the fifth switch are turned on, and the third The switch is cut off; During a second period, the first switch, the second switch, the fourth switch, and the fifth switch are turned off, and the third switch is turned on. The sensing device of the display panel of claim 1, wherein the first gain amplifier comprises: a current mirror, a first end of a main current path coupled to a first end of a servant current path Connected to a system voltage, a second end of the current path of the current mirror is coupled to the output end of the first gain amplifier; a transistor having a control end coupled to the first gain amplifier a first end of the transistor is coupled to a second end of the main current path of the current mirror; and a current source coupled to a second end of the transistor and the current mirror The second end of the servant current path. The sensing device of the display panel of claim 1, wherein the sampling amplifier comprises: a differential amplifier, wherein a first output end and a second output end are respectively coupled to the first of the sampling amplifiers An output terminal and a second output terminal; a fifth capacitor, a first end and a second end are respectively coupled to the first output end of the sensor and a first input end of the differential amplifier a sixth capacitor, a first end and a second end are respectively coupled to the second output end of the sensor and a second input end of the differential amplifier; a seventh capacitor, a first One end is coupled to the first input end of the differential amplifier; An eighth capacitor having a first end coupled to the second input of the differential amplifier; a sixth switch having a first end and a second end coupled to the first input of the differential amplifier And the first output end of the differential amplifier; a seventh switch, wherein the first end and the second end are respectively coupled to a second end of the seventh capacitor and the common mode voltage; an eighth switch The first end and the second end are respectively coupled to the second end of the seventh capacitor and the first output end of the differential amplifier; a ninth switch, the first end and the second end are respectively coupled to The second input end of the differential amplifier and the second output end of the differential amplifier; a tenth switch, wherein the first end and the second end are respectively coupled to a second end of the eighth capacitor and the a common mode voltage; and an eleventh switch, wherein the first end and the second end are respectively coupled to the second end of the eighth capacitor and the second output end of the differential amplifier. The sensing device of the display panel of claim 8, wherein the first switch, the second switch, the sixth switch, the seventh switch, the ninth switch and the first period The tenth switch is turned on, and the third switch, the eighth switch and the eleventh switch are turned off; and in a second period, the first switch, the second switch, the sixth switch, the seventh The switch, the ninth switch and the tenth switch are turned off, and the third switch, the eighth switch and the eleventh switch are turned on. A sensing device for a display panel, comprising: a sensor, the input end of which is coupled to a pixel circuit of the display panel via a data line of the display panel to sense a threshold voltage of a current source transistor in the pixel circuit during a sensing period; And a sampling amplifier, a first input end and a second input end are respectively coupled to a first output end and a second output end of the sensor; wherein the sampling amplifier comprises: a differential amplifier A first output end and a second output end are respectively coupled to a first output end and a second output end of the sampling amplifier; a first capacitor and a first end and a second end are respectively coupled to The first output end of the sensor and a first input end of the differential amplifier; a second capacitor, a first end and a second end are respectively coupled to the second output of the sensor And a second input terminal of the differential amplifier; a third capacitor coupled to the first input end of the differential amplifier; a fourth capacitor coupled to the first end of the fourth capacitor a second input of the differential amplifier; a first switch, the first end and the second The first input end of the differential amplifier is coupled to the first output end of the differential amplifier, and the second end of the second switch is coupled to the first end of the third capacitor a second terminal and a common mode voltage; a third switch having a first end and a second end coupled to the second end of the third capacitor and the first output end of the differential amplifier; a fourth switch, the first end and the second end are respectively coupled to the second input end of the differential amplifier and the second output end of the differential amplifier; a fifth switch, the first end thereof The two ends are respectively coupled to a second end of the fourth capacitor and the common mode voltage; and a sixth switch, wherein the first end and the second end are respectively coupled to the second end of the fourth capacitor and the second end The second output of the differential amplifier. The sensing device of the display panel of claim 10, wherein the first switch, the second switch, the fourth switch, and the fifth switch are turned on, and the third The switch and the sixth switch are turned off; and in a second period, the first switch, the second switch, the fourth switch and the fifth switch are turned off, and the third switch and the sixth switch are turned on . The sensing device of the display panel of claim 10, wherein the sensor comprises: a seventh switch, the first end of which is coupled to the pixel circuit via the data line; and an eighth switch The first end is coupled to the common mode voltage; the first end and the second end are respectively coupled to the second end of the seventh switch and the second end of the eighth switch; a fifth capacitor The first end and the second end are respectively coupled to a first reference voltage and a second end of the seventh switch; a sixth capacitor, the first end and the second end are respectively coupled to a second reference voltage And a second end of the eighth switch; a first gain amplifier having an input coupled to the second of the seventh switch And the output end of the first gain amplifier is coupled to the first input end of the sampling amplifier as the first output end of the sensor; and a second gain amplifier having an input end coupled to the The second end of the eighth switch, and the output of the second gain amplifier is coupled to the second input of the sampling amplifier as the second output of the sensor. The sensing device of the display panel of claim 12, wherein the first switch, the second switch, the fourth switch, the fifth switch, the seventh switch and the first period The eighth switch is turned on, and the third switch, the sixth switch and the ninth switch are turned off; and in a second period, the first switch, the second switch, the fourth switch, the fifth switch The seventh switch and the eighth switch are turned off, and the third switch, the sixth switch, and the ninth switch are turned on. The sensing device of the display panel of claim 12, wherein the first gain amplifier and the second gain amplifier are both unit gain amplifiers. The sensing device of the display panel of claim 12, wherein the first gain amplifier comprises: a current mirror, a first end of a main current path coupled to a first end of a servant current path Connected to a system voltage, a second end of the current path of the current mirror is coupled to the output end of the first gain amplifier; a transistor having a control end coupled to the first gain amplifier a first end of the transistor coupled to a second end of the main current path of the current mirror; A current source is coupled to a second end of the transistor and the second end of the current path of the current mirror. The sensing device of the display panel of claim 10, wherein the sensor comprises: a seventh switch, the first end of which is coupled to the pixel circuit via the data line; and an eighth switch The first end is coupled to the common mode voltage; the first end and the second end are respectively coupled to the second end of the seventh switch and the second end of the eighth switch; a fifth capacitor The first end and the second end are respectively coupled to a first reference voltage and a second end of the seventh switch; a sixth capacitor, the first end and the second end are respectively coupled to a second reference voltage a second end of the eighth switch; a first capacitor coupled to the second end of the seventh switch; a first capacitor coupled to the second end of the eighth switch a first gain amplifier having an input coupled to the second end of the seventh capacitor, and an output of the first gain amplifier coupled to the sample amplifier as the first output of the sensor The first input end; a second gain amplifier having an input end coupled to the second end of the eighth capacitor, and the The output end of the second gain amplifier is coupled to the second input end of the sampling amplifier as a second output end of the sensor; a tenth switch, the first end and the second end are respectively coupled to the first An input of a gain amplifier and a bias voltage; An eleventh switch, the first end and the second end are respectively coupled to the input end of the second gain amplifier and the bias voltage. The sensing device of the display panel of claim 16, wherein the first switch, the second switch, the fourth switch, the fifth switch, the seventh switch, the first period The eighth switch, the tenth switch and the eleventh switch are turned on, and the third switch, the sixth switch and the ninth switch are turned off; and in a second period, the first switch, the second switch The switch, the fourth switch, the fifth switch, the seventh switch, the eighth switch, the tenth switch and the eleventh switch are off, and the third switch, the sixth switch and the ninth switch To be conductive.