# US 2017/0286747 A1 · Unit pixel of fingerprint sensor and fingerprint sensor including the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0286747 A1 - Document ID: US20170286747A1 - Status: Published application - Kind: A1 - Application number: 15/392,242 - Filed: 2016-12-28 - Published: 2017-10-05 - Earliest claimed: 2016-03-29 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Sun Kwon KIM; Choong Hoon LEE; Yun Jeong KIM - Web page: https://patentgrep.com/patent/US20170286747A1 ## CPC - G06V 40/1365: {Matching; Classification} - G06V 40/1306: {non-optical, e.g. ultrasonic or capacitive sensing} - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING ## Abstract A unit pixel of a fingerprint sensor is provided. The unit pixel includes a sensing electrode located to form a capacitance with an object touching a touch surface, a first switch connected between a first node and a second node to transmit at least one driving voltage input through the second node, the first node connected to the sensing electrode, the switch configured to the sensing electrode, an amplifier configured to receive a signal from the sensing electrode and amplify the signal, and a first capacitor connected between a first input terminal and an output terminal of the amplifier, the first capacitor configured to transmit the signal from the sensing electrode to the output terminal. The amplifier is configured to output a different output voltage according to the at least one driving based on an operation of the first switch. ## Claims ### Claim 1 A unit pixel comprising: a sensing electrode located to form a capacitance with an object touching a touch surface; a first switch operably connected between a first node and a second node, the first node connected to the sensing electrode, the first switch configured to transmit at least one driving voltage input through the second node to the sensing electrode; an amplifier configured to receive a signal from the sensing electrode and amplify the signal; and a first capacitor operably connected between a first input terminal and an output terminal of the amplifier, the first capacitor configured to transmit the signal from the sensing electrode to the output terminal, wherein the amplifier is configured to output a different output voltage according to the at least one driving voltage based on an operation of the first switch. ### Claim 2 (depends on 1) The unit pixel of claim 1, wherein, the unit pixel is configured to charge the capacitance between the object and the sensing electrode with a first driving voltage based on a first control signal for controlling the operation of the first switch, and the unit pixel is configured to connect the first input terminal and the output terminal of the amplifier to each other and reset the first capacitor. ### Claim 3 (depends on 2) The unit pixel of claim 2, wherein the unit is configured to transfer a signal based on the capacitance to the first input terminal of the amplifier, the unit pixel configured to transfer the signal based on a second control signal and after the first control signal is generated. ### Claim 4 (depends on 3) The unit pixel of claim 3, wherein the first driving voltage is higher than an operating voltage of the amplifier. ### Claim 5 (depends on 1) The unit pixel of claim 1, wherein during a first period, the unit pixel charges the capacitance between the object and the sensing electrode with a first driving voltage and the amplifier outputs a first output voltage based on the capacitance that has been charged with the first driving voltage; and during a second period, the unit pixel charges the capacitance between the object and the sensing electrode with the third driving voltage and the amplifier outputs a second output voltage based on the capacitance that has been charged with the second driving voltage. ### Claim 6 (depends on 5) The unit pixel of claim 5, wherein correlated double sampling is performed on the first and second output voltages. ### Claim 7 (depends on 5) The unit pixel of claim 5, wherein the first driving voltage is lower than an external power supply voltage and higher than a common voltage, a second input terminal of the amplifier is configured to receive the common voltage, and the second driving voltage is lower than the common voltage and higher than a ground voltage. ### Claim 8 (depends on 1) The unit pixel of claim 1, further comprising: a first metal layer forming the sensing electrode, the first metal layer including a top configured to form the capacitance, the metal layer further including a bottom connected to the first node; and a second metal layer connected to the first input terminal of the amplifier, wherein the first metal layer is closer to the touch surface than the second metal layer. ### Claim 9 (depends on 8) The unit pixel of claim 8, wherein the capacitance with the object is a first capacitance, the first metal layer and the second metal layer form a second capacitance, the second metal layer and a substrate form a third capacitance, and the second capacitance is higher than the third capacitance. ### Claim 10 (depends on 9) The unit pixel of claim 9, wherein the second metal layer is configured to discharge the second capacitance and the third capacitance based on a first control signal. ### Claim 11 A fingerprint sensor comprising: a pixel array including a plurality of unit pixels; and a voltage generator configured to generate at least one driving voltage, wherein each of the unit pixels includes, a sensor configured to sense a capacitance generated from a sensing electrode based on the at least one driving voltage; a transmitter configured to transmit a signal output from the sensor; and an amplifier configured to amplify the signal output from the sensor and output an amplified signal to an output node, wherein the amplifier is configured to output a different output voltage according to the at least one driving voltage. ### Claim 12 (depends on 11) The fingerprint sensor of claim 11, wherein the sensor is configured to sense the capacitance generated from the sensing electrode based on a first driving voltage and the amplifier is configured to be reset based on a first control signal, and the transmitter is configured to transmit the signal output from the sensor to the amplifier based on a second control signal and after the first control signal is generated. ### Claim 13 (depends on 12) The fingerprint sensor of claim 12, wherein the sensor includes a first transistor configured to operate in response to the first control signal, and the transmitter includes a second transistor configured to operate in response to the second control signal. ### Claim 14 (depends on 11) The fingerprint sensor of claim 11, wherein during a first period, the transmitter transmits the signal output from the sensor based on a first driving voltage and the amplifier outputs a first output voltage based on the signal output from the sensor; and during a second period, the sensor outputs a signal generated from the sensing electrode based on a second driving voltage and the amplifier outputs a second output voltage based on the signal output from the sensor. ### Claim 15 (depends on 14) The fingerprint sensor of claim 14, further comprising: a correlated double sampling (CDS) circuit configured to perform CDS on the first and second output voltages transmitted from the unit pixel. ### Claim 16 A fingerprint sensor comprising: a pixel, the pixel including, a first layer configured to establish a capacitance with a top surface of the pixel upon the top surface being contacted by an object in a first operating phase, the first layer configured to receive a driving voltage in the first operating phase, and an amplifier configured to receive a signal based on the capacitance and receive a common voltage, the amplifier configured to output an output voltage based on the signal in the second operating phase, the amplifier further configured to output the common voltage in the first operating phase. ### Claim 17 (depends on 16) The fingerprint sensor of claim 16, wherein the pixel further includes, a first switch operably connected between a first node and a voltage source, the first node being connected to the first layer, the first switch configured to provide the driving voltage to the first layer in the first operating phase. ### Claim 18 (depends on 17) The fingerprint sensor of claim 17, wherein the pixel further includes, a second switch operably connected between the first node and an input terminal of the amplifier, the second switch configured to provide the signal based on the capacitance in the second operating phase. ### Claim 19 (depends on 17) The fingerprint sensor of claim 17, wherein the pixel further includes, a capacitor operably connected between an input terminal of the amplifier and an output terminal of the amplifier; and a second switch connected in parallel with the capacitor. ### Claim 20 (depends on 19) The fingerprint sensor of claim 19, wherein the fingerprint sensor is configured to close the second switch in the first operating phase.