1. An integrated-circuit, continuous-time, sigma-delta analogue-to-digital converter having a single-ended analogue input, a converter reference input, and a ground connection, wherein the converter comprises an input resistor having a first end connected to the single-ended analogue input, and an offset resistor having a first end connected to ground, wherein the second ends of the input and offset resistors are connected to an input to a differential amplifier in an RC integrator circuit, wherein the input to the differential amplifier is also selectably connectable through a reference resistor to either the converter reference input or to ground, and wherein the gain of the converter is determined as a function of the ratio of the input resistor value to the reference resistor value and of the ratio of the offset resistor value to the reference resistor value.
2. The analogue-to-digital converter of claim 1, wherein a first end of the reference resistor is connected to a switching arrangement, arranged to maintain the voltage at the first end of the reference resistor at either ground or a voltage at the converter reference input, with the second end of the reference resistor being connected to the differential amplifier input.
3. The analogue-to-digital converter of claim 1, comprising first and second reference resistors and configured to maintain a first end of the first reference resistor at ground and to maintain a first end of the second reference resistor at a voltage at the converter reference input, with the input to the differential amplifier being connected to a switching arrangement, arranged to connect the input either to the second end of the first reference resistor or to the second end of the second reference resistor.
4. The analogue-to-digital converter of claim 3, wherein the first and second reference resistors have the same nominal value.
5. The analogue-to-digital converter of claim 1, wherein the mid-scale of the converter is determined as a further function of the ratio of the input resistor value to the reference resistor value and of the ratio of the offset resistor value to the reference resistor value.
6. The analogue-to-digital converter of claim 1, comprising a clocked comparator arranged to receive an output from the integrator, and a counter arranged to receive the binary output of the comparator.
7. The analogue-to-digital converter of claim 6, wherein the counter is arranged to receive a clock signal and to count for how many clock cycles the output of the comparator is high, or to count for how many clock cycles the output of the comparator is low, over a time period, and wherein the converter is arranged so that the counter and the comparator receive the same clock signal.
8. The analogue-to-digital converter of claim 1, wherein the converter is an incremental converter.
9. The analogue-to-digital converter of claim 1, wherein the input resistor and the offset resistor are variable, and the converter is arranged to receive an input representative of a desired gain or mid-scale, and to adjust the input and offset resistors so that the converter provides the desired gain or mid-scale.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A bolometer type infrared detector comprising:
a bolometer thin film serving as infrared ray detecting element, said bolometer thin film being divided into a plurality of rectangular elements, said elements being connected in series.
2. A bolometer type infrared detector as set forth in claim 1, wherein number of said elements is determined with reference to an allowable value of a Joule heat to be generated by said bolometer thin film.
3. A bolometer type infrared detector as set forth in claim 1, wherein said bolometer thin film is consisted of a plurality of said elements having mutually different widths.
4. A bolometer type infrared detector as set forth in claim 1, wherein said bolometer thin film is arranged in a two-dimensional matrix on a signal read out circuit wafer.
5. A bolometer type infrared detector comprising:
a thermoelectric converting portion consisted of a supporting film, a bolometer thin film provided on said support film and a protection layer provided on said bolometer thin film, said thermoelectric converting portion being supported on a beam for forming a diaphragm structure,
said bolometer thin film being divided into a plurality of rectangular elements, and said plurality of rectangular elements being connected in series.
6. A bolometer type infrared detector as set forth in claim 5, wherein number of said elements is determined with reference to an allowable value of a Joule heat to be generated by said bolometer thin film.
7. A bolometer type infrared detector as set forth in claim 5, wherein said bolometer thin film is consisted of a plurality of said elements having mutually different widths.
8. A bolometer type infrared detector as set forth in claim 5, wherein said bolometer thin film is arranged in a two-dimensional matrix on a signal read out circuit wafer.