In a pyroelectric infrared detector in which a pyroelectric element and an integrated circuit performing processing of a detection signal from the pyroelectric element are housed in a package, the integrated circuit includes: a converter that performs analog-to-digital conversion of the detection signal; a signal processor that performs signal processing by a digital filter for the detection signal after the conversion; and an input-output controller that delivers the output data from the signal processor to an external device via serial data communication. A cut-off frequency of the digital filter is settable and changeable by voltage application to the integrated circuit or by a command supplied from the external device via the serial data communication.

A control device may comprise a passive infrared sensing circuit configured to operate in a charging state to charge one or more capacitors to appropriate voltages for operation in an operational state of the sensing circuit. The sensing circuit may comprise a pyroelectric detector configured to generate an output signal in response to received infrared energy, and first and second amplifier circuits configured to amplify the output signal. The control device may comprise a control circuit coupled to receive a sensing signal from the second amplifier circuit. Prior to the operational state, a capacitor of the first amplifier circuit may charge through a diode coupled between an output and an inverting input of an operational amplifier. In addition, prior to the operational state, a capacitor of the passive infrared sensing circuit may charge through the control circuit until the magnitude of a voltage across the capacitor exceeds a threshold voltage.

A temperature sensor includes a first electrode, second electrode, and a pyroelectric layer between the first electrode and the second electrode. The pyroelectric layer includes a ferroelectric polymer and an ionogel.

A temperature sensor includes a first electrode, second electrode, and a pyroelectric layer between the first electrode and the second electrode. The pyroelectric layer includes a ferroelectric polymer and an ionogel.

A detection sensor according to an aspect of the invention includes a vibratable film constituted by a piezoelectric film, a case accommodating the vibratable film, and a circuit board. The vibratable film is configured to be irradiated with infrared rays and thereby generate first electric signals through a pyroelectric effect, and configured to be vibrated by sound waves and thereby generate second electric signals through a piezoelectric effect. The case includes a transmissive part. The transmissive part is configured to transmit at least infrared rays and disposed on one side in a first direction relative to the vibratable film to face the vibratable film. The first direction is a thickness direction of the vibratable film. The circuit board is fixed to the case and disposed on the other side in the first direction relative to the vibratable film. The circuit board has a sound hole to input therethrough sound waves.

A temperature sensor includes a first electrode, second electrode, and a pyroelectric layer between the first electrode and the second electrode. The pyroelectric layer includes a ferroelectric polymer and an ionogel.

A temperature sensor includes a first electrode, second electrode, and a pyroelectric layer between the first electrode and the second electrode. The pyroelectric layer includes a ferroelectric polymer and an ionogel.

A control device may comprise a passive infrared sensing circuit configured to operate in a charging state to charge one or more capacitors to appropriate voltages for operation in an operational state of the sensing circuit. The sensing circuit may comprise a pyroelectric detector configured to generate an output signal in response to received infrared energy, and first and second amplifier circuits configured to amplify the output signal. The control device may comprise a control circuit coupled to receive a sensing signal from the second amplifier circuit. Prior to the operational state, a capacitor of the first amplifier circuit may charge through a diode coupled between an output and an inverting input of an operational amplifier. In addition, prior to the operational state, a capacitor of the passive infrared sensing circuit may charge through the control circuit until the magnitude of a voltage across the capacitor exceeds a threshold voltage.

Described herein are techniques for reducing spike noise arising in pyroelectric infrared sensors due to charge build up. The sensors developed by the inventors and described herein rely on the use of dummy elements positioned to prevent or limit charge build-up in the unused space. A first sensing element comprises a first portion of the first layer of conductive material, a first portion of the layer of pyroelectric material, a first portion of the second layer of conductive material and a first absorption region coupled to the first portion of the first layer of conductive material. A dummy element comprises a second portion of the first layer of conductive material, a second portion of the layer of pyroelectric material and a second portion of the second layer of conductive material. The first layer of conductive material defines a first gap between the first portion of the first layer of conductive material and the second portion of the first layer of conductive material.

Described herein are techniques for reducing spike noise arising in pyroelectric infrared sensors due to charge build up. The sensors developed by the inventors and described herein rely on the use of dummy elements positioned to prevent or limit charge build-up in the unused space. A first sensing element comprises a first portion of the first layer of conductive material, a first portion of the layer of pyroelectric material, a first portion of the second layer of conductive material and a first absorption region coupled to the first portion of the first layer of conductive material. A dummy element comprises a second portion of the first layer of conductive material, a second portion of the layer of pyroelectric material and a second portion of the second layer of conductive material. The first layer of conductive material defines a first gap between the first portion of the first layer of conductive material and the second portion of the first layer of conductive material.