It is known to provide infrared sensors in which a plurality of pixels are provided in an array. The pixels are sensitive to temperature, irrespective of whether the temperature change is a result of the ambient temperature around the pixel, for example the temperature of the substrate on which the pixel is provided, or whether the temperature results from infrared radiation impinging on and heating the pixel.
The changes in resistance as a result of a change in temperature can be very small, as can the temperature changes that are being measured. In order to resolve the small differences in resistance, it is known to compare the resistance of each of the temperature dependent resistors of a pixel of the infrared sensor with a reference resistor(s) which is not exposed to the incident infrared radiation, for example, in a Wheatstone bridge arrangement.
Whilst using a bridge or similar arrangement provides enhanced sensitivity to changes in resistance, it can also make the array of sensors vulnerable to mismatch between the resistors.
USPTO Backgrounds
USPTO Backgrounds