JP2002236051A - Bolometer type infrared sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-priced and compact infrared sensor with high- sensitivity by applying a bolometer material having hysteresis in resistance temperature characteristics to the infrared sensor. SOLUTION: A bolometer heat-sensitive part, which has hysteresis characteristics given a temperature cycle in which temperature is raised and fallen periodically repeatedly. Here, a temperature difference ΔTc of the temperature cycles is so determined, that ΔTc>ΔT+|ΔTobj|, where ΔTobj is the temperature variation accompanying light quantity variation, after one cycle. To actualize the temperature cycles, a current is periodically supplied to a bolometer is generate Joule's heat. At the same time, a resistance value is also measured at the same time, by making good use of the supply of the current. This current control and read operation for the resistance value are performed, together by an IC circuit which is adjacent to an element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a bolometer type infrared sensor, and more particularly to a bolometer type infrared sensor using a bolometer material having hysteresis in resistance temperature characteristics.

[0002]

2. Description of the Related Art A bolometer type infrared sensor is a sensor which irradiates infrared rays to a thermally separated bolometer material and detects infrared rays by a resistance change caused by a temperature change. FIG. 4 is a diagram showing the structure of a conventional example of this type of bolometer-type infrared sensor. FIG. 4A is a plan view, and FIG.
3 is a sectional view taken along line AA ′ of FIG. As shown in FIG. 2B, the diaphragm 10 is formed on the bolometer thin film 5 and the support film 3 formed thereunder, a protective film formed on the upper surface of the bolometer thin film 5, and an outer surface of the protective film. The infrared absorption film 7 is provided. The diaphragm 10 has the electrodes 4 on both ends of the bolometer thin film 5. The electrode 4 is connected to the electrode wiring 14, and infrared rays are detected by applying a voltage to the electrode 4 and reading a resistance change caused by a temperature change of the bolometer thin film 5.

[0003] This infrared sensor is designed such that a diaphragm 10 is suspended by beams 12, 12 ', whereby the bolometer thin film 5 is thermally separated. A complete reflection film 1 is provided on a substrate 2, a cavity 9 is provided between the reflection film 1 and the diaphragm 10, and the distance between the reflection film 1 and the diaphragm 10 is optimally limited, whereby a diaphragm is provided. Most of the incident infrared light 11 absorbed by the infrared absorption film 7 on the surface is absorbed by the diaphragm 10 including the bolometer thin film 5 without being lost. As a result, the temperature of the diaphragm increases, and the resistance of the bolometer thin film 5 changes. In FIG.
The bank 16 on the substrate 2 forms the side wall of the cavity 9, and the gap between the diaphragm 10 and the bank 16 is thermally shut off by the slit 8. It should be noted that reference numerals 13, 13 'in FIG.
Are the roots of the beams 12, 12 ', respectively,
5 is a contact for the electrode wiring.

As a bolometer material of such a bolometer type infrared sensor, a temperature coefficient of resistance (TCR), which is a resistance change rate per one degree of temperature change, is used.
Materials having high entof resistance ([% / K]) are desired. Metals, metal oxides, and semiconductors having such characteristics have been reported. For example, Japanese Patent Application Laid-Open No. Hei 5-2065
26, U.S. Pat. No. 7,688,801 discloses a technique using n-type or p-type doped amorphous silicon (a-Si) as a bolometer material. Also, vanadium oxide or a material based on it is commonly used in bolometers and is described in the literature Solar Energy Materia
ls 14, 205 (1986) and references Physical Review B 22, 2626
(1980) and their properties have been reported.

[0005]

Although the a-Si bolometer material has a relatively high TCR value of about 3% / K, it has a high specific resistance exceeding 1000 Ωcm. As described above, when the specific resistance is high, large Johnson noise is added when reading out the resistance value, and the substantial sensitivity to infrared rays does not become very high. On the other hand, when the specific resistance is extremely small, the effect of the wiring resistance appears and high sensitivity cannot be obtained. Therefore, the specific resistance is 0.01
A desirable value is about 1 Ωcm.

On the other hand, vanadium oxide or a material based on vanadium oxide has a relatively low specific resistance (up to 0.1 Ωcm) and a TCR of about 2% / K. However, in order to aim for a sensor with higher sensitivity, a larger TCR
Is required. Larger TC using vanadium oxide
In order to obtain R, there is a method utilizing the phase transition of vanadium oxide. Before and after the phase transition of vanadium oxide, a resistance change of two digits or more is generally observed. Further, by doping vanadium oxide with various metals, the transition temperature can be controlled to an appropriate temperature. For this reason, if vanadium oxide is used as a bolometer, high-sensitivity infrared detection characteristics can be expected.

However, it is known that the specific resistance of vanadium oxide has hysteresis with respect to the cycle of temperature change. Conventionally, a bolometer material having a specific resistance temperature characteristic having a hysteresis cannot be used as an infrared light receiving element material for the following reason.

FIG. 5 is a diagram showing a hysteresis curve of a material having a hysteresis in the specific resistance-temperature characteristic. In FIG. 5, the low temperature side stable phase is a first phase, and the high temperature side stable phase is a second phase. In the following description, a point in the figure (that is, a set of a bolometer temperature and a bolometer resistance corresponding to the temperature) is referred to as a “state” of the bolometer.

The specific resistance ρ of the bolometer material shown in FIG. 1 (indicated by logarithm in FIG. 5) changes as follows with a change in temperature. First, when the temperature is increased from the state a of the first phase, the specific resistance gradually changes until reaching the critical state b. When the temperature is further increased beyond the critical state b, phase transition starts and the specific resistance sharply decreases. When the state c is reached in this way, even if the temperature is further increased, the abrupt change in the specific resistance no longer occurs, and the specific resistance gradually changes again. That is, the bolometer material undergoes a phase transition from the first phase to the second phase between the state b and the state c, ends the phase transition in the critical state c, and shifts to the second phase, which is a high-temperature-side stable phase. In the following description, the curve bc is referred to as a heating curve.

Next, when the temperature of the bolometer material is lowered from the state f of the second phase, no phase transition occurs even if the temperature reaches the temperature corresponding to the state c, and the bolometer material maintains the second phase. In this temperature range, the specific resistance of the bolometer material changes slowly. When the temperature is further lowered to reach the state d, a phase transition starts and the specific resistance sharply increases. Then, the specific resistance continues to rise sharply to the temperature corresponding to state e. When the temperature is further lowered after the state e, the specific resistance of the bolometer material gradually changes in this temperature range. In the following description, the curve de is referred to as a cooling curve. The bolometer material undergoes a phase transition from the second phase to the first phase in a temperature range corresponding to the temperature drop curve.

It is important to note that when using this type of bolometer material, the phase transition represented by the heating and cooling curves is an irreversible process. Now, let us consider a case where the state of the bolometer material is shifted from the first phase state a to the point p1 on the temperature rise curve via the critical state b, and then the temperature is lowered. At this time, the state of the bolometer material is
Rather than transitioning from the state p1 on the temperature rise curve in the direction of the critical state b in the opposite direction, the transition from the state p1 toward the low temperature side is substantially parallel to the curve ab (leftward from the point p1 in FIG. Transition towards). Then, when the state of the bolometer material reaches the state represented by the point p in FIG. 5 through such a process, when the temperature of the material is increased again, the specific resistance becomes the curve p in FIG. After a gradual change along -p1,
Only when the state of the material reaches the point p1 on the heating curve, the material rapidly changes along the heating curve.

A similar phenomenon occurs when the temperature of the bolometer material is lowered starting from the second phase state f.
Now, consider a case in which the state of the bolometer material is shifted from the second phase state f to the point p2 on the temperature drop curve via the critical state d, and then the temperature is increased. At this time, the state of the bolometer material changes from the state p2 to the critical state d on the temperature drop curve in the opposite direction.
, But from the state p2 toward the high temperature side almost in parallel to the curve df (from the point p2 in FIG. 5 to the right). Then, when the state of the bolometer material reaches the state represented by the point p in FIG. 5 through such a process, when the temperature of the material is decreased again, the specific resistance becomes the curve p in FIG. After a gradual change along -p2, the state of the material changes abruptly along the cooling curve only when the state of the material reaches the point p2 on the cooling curve.

Therefore, in order to obtain a high infrared detection sensitivity using the phase transition, the physicochemical structure corresponding to one point p1 on the heating curve (crystal structure, crystal structure when the bolometer material is a single crystal, Even if a bolometer material having imperfections, the crystal structure of crystal grains when the bolometer material is polycrystalline, crystal imperfections, and the energy state of the crystal grain boundaries is used (for example, in FIG. It can be realized by setting the state to the state p1 on the heating curve and then lowering the temperature to the state p),
Unless the operating temperature is set at the transition temperature corresponding to the state p1, a highly sensitive change in resistivity (change along a hysteresis curve) cannot be realized.

However, since the conventional bolometer operates using the ambient temperature as the operating temperature, even if the physicochemical structure of the bolometer material is the same as the physicochemical structure corresponding to the state on the hysteresis curve, There is a problem that it is not always possible to realize a rapid change in specific resistance along the hysteresis curve.

This problem will be described in detail as follows. Temperature resolution (NETD) of infrared sensor is 0.1 ℃
The degree is common. Therefore, the temperature change of the bolometer caused by infrared rays from the subject for which high sensitivity detection is required is of this magnitude. As a result, the temperature change of the bolometer caused by such an object is usually sufficiently smaller than the temperature width ΔTt of the hysteresis. In fact, the temperature range ΔTt of this hysteresis was reported to be 1 ° C for VO2, 1 ° C for bolometer material of bulk single crystal, 2 ° C for polycrystalline thin film, and 10 ° C for thin film with poor crystallinity. (J. Vac.Sci. Tchnol.A15, 1113 (199
7)). A value of 50 ° C has been reported for V2O3 doped with 1 mol% Cr ((Physical Review
B 22, 2626 (1980)). Under such conditions, when infrared light is incident on the bolometer in the state p (temperature Tobj) in the figure, the bolometer resistance value varies within the hysteresis temperature range as shown by the solid line arrow in the figure. At this time, since the temperature change ΔTobj of the bolometer is smaller than the hysteresis temperature width ΔTt, the temperature Tobj of the bolometer does not reach the transition temperature (the temperature T1 corresponding to the point p1 on the temperature rising curve). Therefore, no phase transition occurs. As a result, a high TCR cannot be obtained, and thus a high infrared detection sensitivity cannot be obtained.

Further, when a material having a temperature hysteresis is used for a bolometer, it cannot be used unless the temperature history (whether the material is in the process of increasing or decreasing) is clear. There's a problem. For example, to realize the state p in FIG. 5, there are two heat treatment processes. The first step is the first phase state a
Starting from, the state p on the heating curve via the critical state b
This is the process of reaching 1 and lowering the temperature from state p1 to state p. The second step starts from state f of the second phase,
After reaching the state p2 on the cooling curve via the critical state d, the state p
This is the process of raising the temperature from 2 to reach the state p.

When the material temperature in the state p generated by the first process is increased from Tobj, the specific resistance ρ (in FIG. 5,
logρ) changes slowly along the curve p-p1, and when the temperature of the material reaches T1 corresponding to the state p1, thereafter changes sharply with increasing temperature. However, when the temperature of this material is lowered from Tobj corresponding to the state p, the specific resistance becomes
It changes gently almost along the extension of the straight line p1-p. At that time, even if the extension line intersects with the temperature drop curve, a gradual change is continued without phase transition. The reason is that this material is in a state where only the temperature is changed while the physicochemical constitution in the state p1 on the temperature rising curve is frozen, so that the phase transition is performed unless the temperature returns to the state p1 again. Because they cannot do it.

When the material temperature in the state p generated by the second process is decreased from Tobj, the specific resistance ρ gradually changes along the curve p-p2, and the temperature of the material becomes the temperature corresponding to the state p2. Once reached, it then rises sharply with decreasing temperature. However, the temperature of this material is set to T
When the resistance is increased from obj, the specific resistance gradually changes almost along the extension of the straight line p2-p. At that time, even if the extension line intersects with the temperature rise curve, a gradual change is continued without phase transition. The reason is that this material
Since only the temperature has changed while the physicochemical composition in the state p2 on the temperature drop curve is frozen, the phase transition cannot be performed unless the temperature returns to the temperature corresponding to the state p2 again. Because.

For these reasons, even if the bolometer materials have the same chemical composition (the same doping concentration) and are in the same state p, they perform the opposite operation depending on the history of the heat treatment. This is the second reason that hysteretic materials cannot be used in bolometers. Due to the above problems, there is no report that a material having hysteresis is applied to a bolometer type infrared sensor.

The present invention has been made in view of such a conventional situation, and has as its object to solve the problem of hysteresis in the resistivity-temperature characteristic and to provide a high-sensitivity bolometer-type infrared sensor utilizing a phase transition. And

[0021]

In order to achieve the above object, a bolometer type infrared sensor according to the present invention uses a material having hysteresis in resistance temperature characteristics as a bolometer material and performs a temperature cycle on a bolometer heat-sensitive part. Means to give.

The temperature cycle gives a periodic temperature shift to the bolometer temperature sensitive part. By this temperature shift, the operating temperature of the bolometer temperature sensing section (a reference temperature (zero point temperature) that determines a temperature change caused by a change in the amount of irradiated infrared light) can be set on the hysteresis curve. Thus, a change in specific resistance with respect to a change in temperature can be detected with high sensitivity. The following advantages can be realized by performing the temperature shift periodically. 1) Since the temperature shift is performed periodically, an infrared detection signal (detected as a resistance change) is also detected as a periodic signal. The periodic signal can be easily detected by synchronous signal processing (for example, synchronous rectification) even if it is a weak signal buried in noise. 2) The operating temperature of the bolometer temperature sensing part can be alternately placed on both of the two hysteresis curves (heating curve and cooling curve) by the periodic temperature shift. As a result, both an increase and a decrease in the amount of infrared light can be detected.

In order to realize the advantage of the above 2) in a stable operation, the temperature fluctuation width ΔTc of the temperature cycle is defined as ΔTc> ΔTt
It is desirable to set so as to be + │ΔTobj│. Here, ΔTt is the temperature width of the hysteresis, and ΔTobj is the temperature change of the bolometer heat-sensitive part due to the change in the amount of infrared light emitted from the subject after one cycle of the temperature cycle.

Such a setting is made for the following reason. As described above, in order to use both of the two hysteresis curves, the range of the temperature shift, that is, the fluctuation width ΔTc of the temperature cycle needs to be at least as large as the temperature width ΔTt of the hysteresis. However, if the variation width ΔTc is set as ΔTc = ΔTt, the following problem occurs. For example, when ΔTobj> 0, the bolometer temperature sensing part is warmed by infrared rays, so that the variation width ΔTc of the temperature cycle is Δ
It will be shifted to the heating curve side by Tobj. Therefore,
The operating temperature of the bolometer temperature sensing part is away from the temperature drop curve by ΔTobj, and infrared detection can be performed using the temperature rise curve, but infrared detection cannot be performed using the temperature drop curve. Conversely, when ΔTobj <0, infrared detection cannot be performed using the temperature rise curve.

In order to avoid such a problem, a value obtained by adding | Tobj | to ΔTt in advance is set as the temperature fluctuation width ΔTc, so that the infrared light amount follows the hysteresis curve even if there is any positive or negative fluctuation. Infrared detection using specific resistance change characteristics can be performed.

However, even if the temperature fluctuation width ΔTc is set as described above, the object of the present invention cannot be achieved if the temperature cycle is performed in a temperature region remote from the hysteresis curve. Therefore, the temperature range in which the temperature cycle is performed must be set to a temperature range close to the hysteresis curve. That is, the temperature cycle is
The temperature is set to a temperature range in which a specific resistance change along a hysteresis curve occurs during the temperature cycle.

In order to realize a temperature cycle, in one embodiment of the present invention, a current is intermittently applied to the bolometer heat-sensitive portion to generate Joule heat. In this case,
The temperature rise ΔTc due to the Joule heat is ΔTc> ΔTt +
A current is supplied so that | ΔTobj |.

Further, in order to apply a temperature cycle, in the embodiment of the present invention, when a current is supplied to the bolometer heat-sensitive portion, the bolometer temperature information is read from the current value.

Further, according to the present invention, a plurality of bolometer-type elements are arranged in an array, and the application of a temperature cycle and the reading of temperature information are simultaneously performed by a readout circuit prepared for each pixel. Thereby, a highly sensitive and inexpensive infrared sensor can be obtained.

[0030]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a graph showing a specific resistance temperature characteristic of a bolometer temperature sensing part for explaining the operation principle of the infrared sensor of the present invention. Also in FIG. 1, the bolometer specific resistance ρ is expressed in logarithmic notation (log ρ). In the bolometer, the temperature rise and fall are periodically repeated with a temperature fluctuation width ΔTc larger than the hysteresis temperature width ΔTt. Here, ΔTc is a formula ΔTc> Δ
Tt + ΔTmax is set so as to be satisfied, and ΔTmax is the maximum value of the temperature change of the bolometer thermosensitive part caused by the expected change in the amount of infrared light.

When the amount of infrared light is the set reference value, the bolometer is set to the state A (temperature Tobj) on the temperature drop curve.
And start the temperature cycle. First, when the temperature rise is started, the bolometer raises the temperature without a physicochemical structural change and the specific resistance curve (represented by A → B in the figure)
Crosses the temperature rise curve in state B. Since ΔTc> ΔTt, the bolometer temperature further rises. State B temperature
Beyond TB, the bolometer rises in temperature with a physicochemical structural change and reaches state C (temperature Tc = Tobj + ΔTc).

Next, when the temperature is lowered, the temperature drops without a change in physicochemical structure, and the specific resistance curve (represented by C → D in the figure) crosses the temperature lowering line in state D. The temperature drops from the temperature in the state D to the first temperature Tobj with a physicochemical structural change.

When the amount of infrared light decreases, the amount of heat emitted from the bolometer due to the decrease in the amount of infrared light during this temperature cycle is constant, and this amount of heat acts to lower the temperature of the bolometer by ΔTobj. Therefore, the temperature cycle shifts to the low temperature side (left side in the figure) by ΔTobj. Point A ′ in FIG. 1 is the starting point of the next temperature cycle. Thus, by detecting ΔTobj,
A change in the amount of infrared light can be detected while maintaining a high TCR.

In the embodiment shown in FIG. 1, the case where the starting point of the temperature cycle is set on the cooling curve is described. However, the same result can be obtained when the starting point of the temperature cycle is other than the hysteresis curve. FIG. 2 is a diagram illustrating an example of a temperature cycle when the start point of the temperature cycle is set to a point other than the hysteresis curve.

FIG. 2 shows a point C on the outer side (higher temperature side) of the heating curve.
Is set as the start point of the temperature cycle, and the bolometer temperature is first decreased and then increased. The temperature range in which the temperature cycle is performed is T1 to T2, and this temperature range is in the range of the temperature range TD to TU where hysteresis of the resistivity-temperature characteristic occurs. The temperature fluctuation width ΔTc> ΔTt.

Referring to FIG. 2, starting from state C (temperature T2), the bolometer temperature is decreased. The bolometer material reaches the point D on the temperature drop curve across the temperature rise curve without causing a physicochemical structural change. When the temperature is further lowered, the state A (temperature T1) is reached along the temperature drop curve (while undergoing physicochemical structural change). In the next heating process, the bolometer material reaches the state B on the heating curve without causing a physicochemical structural change. As the temperature of the bolometer material further rises, the material follows the temperature rise curve (while producing a physicochemical structural change) at a point E (temperature T) on the temperature rise curve.
2) reach. This ends the first cycle. Since the second cycle starts from the point E on the temperature rising curve, the operation is exactly the same as the temperature cycle in FIG. Therefore, if the infrared detection is performed in the temperature cycle after the second cycle, the same method as that in FIG. 1 can be applied.

The conditions for causing the bolometer type infrared sensor of the present invention to perform a stable operation are as follows.
Tc is defined as ΔTobj, where ΔTobj is the temperature change due to the light quantity change after one cycle, and ΔTc is determined so that ΔTc> ΔTt + | ΔTobj | (1). Is set within the temperature range TD to TU where the temperature occurs.

In the infrared sensor of the present invention, in order to realize a temperature cycle, a current is intermittently supplied to the bolometer to generate Joule heat. As a result, a special temperature raising / lowering device was not required, and a compact sensor was realized. At the same time, the resistance value was measured using the flow of current. Such current control and resistance reading operation were performed collectively by an IC circuit adjacent to the element.

FIG. 3 is a diagram illustrating a temperature cycle in which a current is supplied to the bolometer and the temperature is repeatedly increased and decreased for each frame. The resistance value is measured by the applied voltage and the flowing current. The temperature difference ΔTc in this case is represented by ΔTc = VB2 (1−exp (−τro / τT)) / G RB (2) Here, VB is the bias voltage applied to the bolometer, t ro is the read time, t T is the thermal time constant, G is the thermal conductance, and RB is the resistance of the bolometer. In the present embodiment, the elements shown in FIG. 4 were arranged at 50 μm intervals to form an array element, and ΔTc was designed to be 12.9 ° C. In addition, a VO2 thin film with intentionally increased oxygen defects was used as a bolometer material so as to reach a transition point near room temperature. The TCR of this film is 10% / K. The TCR of VO2 in a region where there is no ordinary phase transition is about 2% / K. The hysteresis temperature width ΔTt of this film is 5 ° C. Such materials cannot be used in conventional bolometer-type infrared sensors.

When the temperature resolution of the infrared sensor thus obtained was measured, a temperature resolution of 0.02 K was obtained. This is five times the sensitivity of the conventional device using VO2 having no hysteresis, and a high-sensitivity infrared sensor can be realized.

[0042]

As described above, according to the present invention, a periodic temperature bias is applied to a bolometer material having a hysteresis of the specific resistance temperature characteristic, and a minute temperature change generated by infrared absorption at an arbitrary temperature is detected. By converting to a temperature change near the transition temperature, it becomes possible to apply steep specific resistance temperature characteristics due to phase transition to infrared sensors, and as a result, high sensitivity using the specific resistance change due to phase transition of bolometer material An infrared sensor can be realized. In addition, by applying a power cycle to the bolometer material to realize a temperature cycle by Joule heat and measuring the resistance value by the current and voltage to generate the temperature cycle, the infrared sensor including the temperature cycle function can be manufactured at low cost. -It can be realized compactly.

[Brief description of the drawings]

FIG. 1 is a specific resistance temperature characteristic diagram of a bolometer thermosensitive part for explaining the operation principle of an infrared sensor of the present invention.

FIG. 2 is a diagram illustrating an example of a temperature cycle when a start point of the temperature cycle is set to a point other than a hysteresis curve.

FIG. 3 is a diagram illustrating a temperature cycle in which a current is supplied to a bolometer and the temperature is repeatedly increased and decreased for each frame.

4A and 4B are diagrams showing the structure of a conventional example of a bolometer-type infrared sensor, wherein FIG. 4A is a plan view and FIG. 4B is a cross-sectional view along AA ′ of FIG.

FIG. 5 is a diagram illustrating a hysteresis curve of a material having hysteresis in specific resistance-temperature characteristics.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Perfect reflection film 2 Substrate 3 Protective film 4 Electrode 5 Bolometer thin film 6 Protective film 7 Infrared absorption film 8 Slit 9 Cavity 10 Diaphragm 11 Infrared light 12 and 12 'Beams 13 and 13' Base of beam 14 Electrode wiring 15 Contact 16 Bank

Claims (7)

[Claims] 1. An infrared sensor having a temperature-sensitive part using a bolometer material, wherein a material having hysteresis in specific resistance temperature characteristics is used as the bolometer material, and means for giving a temperature cycle to the bolometer heat-sensitive part is provided. A bolometer type infrared sensor characterized by the following. 2. The temperature fluctuation range of the temperature cycle is ΔTc,
Assuming that the temperature width of the hysteresis is ΔTt and the temperature change of the bolometer heat-sensitive part due to a change in the amount of infrared light from the subject after one cycle of the temperature cycle is ΔTobj, ΔTc> ΔTt
+ | ΔTobj |, the temperature fluctuation width ΔTc is set,
2. The bolometer type infrared sensor according to claim 1, wherein the temperature cycle is set in a temperature region in which a specific resistance change along a hysteresis curve occurs during the temperature cycle. 3. The bolometer type according to claim 1, wherein the means for giving the temperature cycle includes a Joule heat generating means for generating a Joule heat by intermittently supplying a current to the bolometer heat sensitive part. Infrared sensor. 4. The temperature rise due to the Joule heat is ΔTc, the temperature width of the hysteresis is ΔTt, and the temperature change due to a change in the amount of light from the subject after one cycle of the temperature cycle is ΔTc.
When Tobj, the Joule heat generating means is ΔTc> Δ
4. The bolometer-type infrared sensor according to claim 3, wherein a current is supplied so as to be Tt + | ΔTobj |. 5. The bolometer-type infrared ray according to claim 3, further comprising temperature reading means for measuring a current of the bolometer heat-sensitive portion to give a temperature cycle and reading temperature information of the bolometer from the current value. Sensor. 6. The method according to claim 3, wherein a plurality of bolometer-type elements are arranged in an array, and the application of a temperature cycle and the reading of temperature information are simultaneously performed by a readout circuit prepared for each pixel. A bolometer-type infrared sensor as described in the above. 7. An infrared detection method for detecting infrared light using a bolometer material, wherein the bolometer material undergoes a phase transition at a known phase transition temperature, and at this phase transition temperature, the specific resistance sharply changes with temperature. Using a material having a changing resistance temperature characteristic, at the time of infrared detection, a temperature bias is applied to the bolometer material to shift the temperature of the material to a phase transition temperature, and the bolometer material is generated in response to the temperature change of the bolometer caused by absorption of infrared light An infrared detection method comprising: detecting a rapid change in specific resistance; and detecting infrared intensity from the change in specific resistance.