# US 2019/0172993 A1 · Thermal pattern sensor with pyroelectric capacitance and hard protective layer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0172993 A1 - Document ID: US20190172993A1 - Status: Published application - Kind: A1 - Application number: 16/207,653 - Filed: 2018-12-03 - Published: 2019-06-06 - Earliest claimed: 2017-12-04 - Assignees: Commissariat A L'energie Atomique Et Aux Energies Alternatives - Applicants: Commissariat A L'energie Atomique Et Aux Energies Alternatives - Inventors: Mohammed BENWADIH; Christophe SERBUTOVIEZ - Web page: https://patentgrep.com/patent/US20190172993A1 ## CPC - H10N 15/10: Thermoelectric devices using thermal change of the dielectric constant, e.g. working above and below the Curie point - G01J 5/34: using capacitors, e.g. pyroelectric capacitors - G06V 40/1306: {non-optical, e.g. ultrasonic or capacitive sensing} - G06V 40/1329: {Protecting the fingerprint sensor against damage caused by the finger} - H10N 19/00: Integrated devices, or assemblies of multiple devices, comprising at least one thermoelectric or thermomagnetic element covered by groups H10N10/00 - H10N15/00 - H10N 15/15: {Thermoelectric active materials} - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING ## Abstract Thermal pattern sensor comprising several pixels arranged on a substrate, each pixel including at least: a pyroelectric capacitance formed by at least one portion of pyroelectric material arranged between at least one lower electrode and at least one upper electrode, with the lower electrode arranged between the substrate and the portion of pyroelectric material, a dielectric layer such that the upper electrode is arranged between the portion of pyroelectric material and the dielectric layer, a heating element including at least one deposition of electrically conductive particles and such that the dielectric layer is arranged between the upper electrode and the heating element, a protective layer arranged between the dielectric layer and the heating element and including at least one material of which the Shore A hardness is greater than or equal to around 60. ## Claims ### Claim 1 Thermal pattern sensor comprising several pixels arranged on a substrate, each pixel including at least: a pyroelectric capacitance formed by at least one portion of pyroelectric material arranged between at least one lower electrode and at least one upper electrode, with the lower electrode arranged between the substrate and the portion of pyroelectric material, a dielectric layer such that the upper electrode is arranged between the portion of pyroelectric material and the dielectric layer, a heating element including at least one deposition of electrically conductive particles and such that the dielectric layer is arranged between the upper electrode and the heating element, a protective layer arranged between the dielectric layer and the heating element and including at least one material of which the Shore A hardness is greater than or equal to around 60. ### Claim 2 (depends on 1) Thermal pattern sensor according to claim 1, in which the thickness of the protective layer is between around 100 nm and 600 nm. ### Claim 3 (depends on 1) Thermal pattern sensor according to claim 1, in which the protective layer comprises at least one cross-linkable organic polymer material and/or at least one inorganic material of sol-gel and/or SOG type and/or a ceramic material of sol-gel type. ### Claim 4 (depends on 3) Thermal pattern sensor according to claim 3, in which the cross-linkable organic polymer material corresponds to one of the following materials: epoxy, polyurethane, acrylic, or in which the SOG corresponds to one of the following materials: PMMSQ, MSQ, polyquinoxaline, or in which the inorganic material of sol-gel type comprises at least one of the following compounds: Al2O3, TiO2, WO3, SiO2. ### Claim 5 (depends on 1) Thermal pattern sensor according to claim 1, in which the heating element comprises at least one layer of silver particles. ### Claim 6 (depends on 1) Thermal pattern sensor according to claim 1, in which the substrate includes at least one plastic material. ### Claim 7 (depends on 1) Thermal pattern sensor according to claim 1, in which the lower and upper electrodes comprise at least one of the following materials: silver, gold, copper, nickel, carbon, graphene, conductive polymer. ### Claim 8 (depends on 1) Thermal pattern sensor according to claim 1, in which said thermal pattern sensor is a finger print sensor. ### Claim 9 Method for producing a thermal pattern sensor comprising several pixels arranged on a substrate, each produced by the implementation of the following steps: producing at least one lower electrode on a substrate; producing at least one portion of pyroelectric material at least on the lower electrode; producing at least one upper electrode on the portion of pyroelectric material; producing at least one dielectric layer at least on the upper electrode; producing at least one protective layer on the dielectric layer; producing at least one heating element on the protective layer; in which the lower electrode, the upper electrode and the portion of pyroelectric material form a pyroelectric capacitance, and in which the protective layer comprises a material of which the Shore A hardness is greater than or equal to around 60. ### Claim 10 (depends on 9) Method according to claim 9, in which the heating element comprises at least one layer of silver particles formed by a printing deposition. ### Claim 11 (depends on 9) Method according to claim 9, in which the lower electrode and/or the upper electrode and/or the portion of pyroelectric material are produced by printing depositions. ### Claim 12 (depends on 9) Method according to claim 9, in which said thermal pattern sensor is a finger print sensor.