Active thermal pattern sensor comprising a passive matrix of pixels

A thermal pattern sensor comprising a matrix of several lines and columns of pixels, each pixel including at least:

• a pyroelectric capacitance formed by at least one portion of pyroelectric material arranged between a lower electrode and an upper electrode, in which a first of the lower and upper electrodes corresponds to a reading electrode of the pixel, and
• a heating element able to heat the portion of pyroelectric material of the pyroelectric capacitance of said pixel during a measurement of the thermal pattern by the pyroelectric capacitance of said pixel, and in which:
• for each line of pixels, the heating elements of the pixels of said line are configured to heat the portions of pyroelectric material of the pixels of said line independently of the heating elements of the pixels of the other lines, and
• for each column of pixels, the reading electrodes of each pixel of said column are electrically connected together and formed by at least one first electrically conductive portion in contact with the portions of pyroelectric material of the pixels of said column and distinct from the first electrically conductive portions forming the reading electrodes of the pixels of the other columns.

A method for producing a thermal pattern sensor comprising a matrix of several lines and columns of pixels, including at least the implementation of the following steps:

• producing, for each pixel, a pyroelectric capacitance formed by at least one portion of pyroelectric material arranged between a lower electrode and an upper electrode, in which a first of the lower and upper electrodes corresponds to a reading electrode of the pixel, and
• producing a heating element able to heat the portion of pyroelectric material of the pyroelectric capacitance of said pixel during a measurement of the thermal pattern by the pyroelectric capacitance of said pixel, and in which:
• for each line of pixels, the heating elements of the pixels of said line are able to heat the portions of pyroelectric material of the pixels of said line independently of the heating elements of the pixels of the other lines, and
• for each column of pixels, the reading electrodes of each pixel of said column are electrically connected together and formed by at least one first electrically conductive portion in contact with the portions of pyroelectric material of the pixels of said column and distinct from the first electrically conductive portions forming the reading electrodes of the pixels of the other columns.