JP2003014538A - Thermal radiation detector - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To enable signal processing for reducing the influence of environmental temperature, signal processing for reducing the influence of light amount fluctuation of a light source, image correction processing, and the like. A thermal radiation detection effective element (10) is provided on a substrate (1).
1 and a thermal radiation detection invalid element 102 are provided. The effective element 101 has a supported part. The supported portion includes an infrared absorbing portion that receives infrared rays and converts it into heat, a displacement portion that displaces with respect to the substrate 1 in accordance with heat generated by the infrared absorbing portion, and a displacement that occurs in the displacement portion. A reflection plate used to obtain a predetermined change corresponding to the reflection plate. Invalid element 1
Numeral 02 has substantially the same structure as that of the effective element 101, but is configured not to respond to infrared rays to be incident.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal radiation detecting device such as a thermal infrared detecting device.

[0002]

2. Description of the Related Art A conventional thermal infrared detecting device of a capacitance type or a light reading type is provided with a base and at least one thermal radiation detecting element provided on the base and having a supported portion. (JP-A-8-193888, US Pat. No. 3,896,309, JP-A-10-253447.
No. The supported part includes an infrared absorption part that receives infrared rays and converts it into heat, a displacement part that is displaced by the bimetal principle with respect to the base body according to heat generated in the infrared absorption part, and a displacement part. A displacement reading member used to obtain a predetermined change according to the generated displacement. The incident radiation is converted into heat by the infrared absorption section, and the displacement section is curved and displaced according to the heat.

In the case of a light-reading type thermal infrared detecting device, as the displacement reading member, for example, a reflecting plate that reflects the received reading light is used. The reading light is applied to the reflecting plate, and the displacement generated in the displacement portion is read as a change in the reflection angle of the reading light, whereby the incident infrared ray amount is detected.

Further, in the case of the capacitive thermal infrared detector, for example, a movable electrode portion is used as the displacement reading member, and the fixed electrode portion is fixed to the base so as to face the movable electrode portion. To be done. The change in the height of the movable electrode section (the distance between the movable electrode section and the fixed electrode section) due to the displacement generated in the displacement section is read out as the capacitance between both electrode sections, and the incident infrared ray amount is detected by this. To be done.

[0005]

The conventional thermal radiation detection device is based on the principle that radiation is detected by the displacement caused by heat. Therefore, unless a temperature controller such as a Peltier element is used and the temperature of the substrate is strictly controlled with high responsiveness to keep the substrate temperature strictly constant, even if the incident infrared ray amount is the same. However, the displacement amount of the displacement portion changes due to the influence of the environmental temperature. By devising the structure of the supported portion, it is theoretically possible to eliminate the influence of the environmental temperature without using a temperature controller, but due to the manufacturing variations in the dimensions of each structure, etc. It is practically difficult to completely eliminate the effect. Therefore, the infrared detection device using the conventional thermal displacement element cannot accurately detect infrared rays or the like from the target object unless the temperature of the substrate is strictly controlled. If the temperature of the substrate is strictly controlled, the influence of environmental temperature can be reduced and the radiation detection accuracy can be improved, but the cost is inevitable.

Further, in the case of the optical readout type thermal radiation detection device, a light source of readout light for irradiating the element is required.
If the amount of light from this light source fluctuates, it will be affected and
Radiation detection accuracy is reduced.

Further, in the case of an optical readout type thermal radiation detection device, a plurality of thermal radiation detection elements are arranged two-dimensionally,
The displacement reading member of each element is irradiated with the readout light by using a readout optical system, and based on the readout light emitted from each element and changed according to the displacement of the displacement portion, An image of incident radiation can be obtained by forming an optical image according to the displacement of the displacement portion and capturing the optical image with a CCD camera or the like. In this case, if the components of the readout optical system are misaligned due to vibration, shock, thermal expansion, etc., the resulting image of incident radiation undergoes fluctuations such as rotation, distortion, and magnification fluctuations, resulting in deterioration of image quality. To do. However, the conventional optical readout type thermal radiation detection device cannot correct such image fluctuations.

The present invention has been made in view of the above circumstances, and is a signal process for reducing the influence of the ambient temperature, a signal process for reducing the influence of the light amount fluctuation of the light source, and an image correction process. It is an object of the present invention to provide a thermal radiation detection device capable of appropriately performing the above.

[0009]

In order to solve the above-mentioned problems, a thermal radiation detection device according to a first aspect of the present invention comprises a base and at least one thermal radiation effective detection element provided on the base. And at least one thermal radiation detection invalid element provided on the base. And said at least one thermal radiation detection effective element,
A supported portion supported by the base, which absorbs radiation and converts it into heat; a displacement portion that is displaced with respect to the base according to heat generated in the radiation absorption portion; A supported portion having a displacement reading member used for obtaining a predetermined change according to the displacement generated in the displacement portion.
The at least one thermal radiation detection invalid element has substantially the same structure as the thermal radiation detection effective element, but is configured not to respond to incident radiation.

According to the first aspect, unlike the conventional thermal radiation detecting device, not only the thermal radiation detecting element but also the thermal radiation detecting invalid element is provided on the same substrate as the thermal radiation detecting effective element. Has been. The thermal-type radiation detection invalid element has substantially the same structure as the thermal-type radiation detection effective element, but is configured not to respond to incident radiation. Therefore, by correcting the output obtained from the thermal-type radiation detection effective element by using the output obtained from the thermal-type radiation detection invalid element, signal processing for reducing the influence of the environmental temperature and variation of the light amount of the light source are performed. Signal processing for reducing the influence, image correction processing, and the like can be appropriately performed.

In the thermal type radiation detecting apparatus according to the second aspect of the present invention, in the first aspect, the at least one thermal type radiation detection ineffective element is provided with respect to the radiation absorption section of the thermal type radiation detection ineffective element. It has a shielding part for shielding the incidence of the radiation.

In the thermal type radiation detecting device according to the third aspect of the present invention, in the first aspect, the at least one thermal type radiation detection ineffective element has no radiation absorbing portion.

The second and third aspects are specific examples of the thermal radiation detection invalid element, but the thermal radiation detection null element is not limited to these configurations.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the following description, an example in which the radiation is infrared rays and the reading light is visible light will be described. However, in the present invention, the radiation may be X-rays other than infrared rays, ultraviolet rays, and various other radiations. Alternatively, the reading light may be light other than visible light.

FIG. 1 is a schematic plan view schematically showing an optical readout type thermal radiation detection device 100 according to an embodiment of the present invention. For convenience of explanation, as shown in FIG. 1, an X axis, a Y axis, and a Z axis which are orthogonal to each other are defined. 2 to 9 described later also show the X axis, the Y axis, and the Z axis corresponding to the X axis, the Y axis, and the Z axis in FIG. 1, respectively.

The radiation detector 100 according to the present embodiment
As shown in FIG. 1, a substrate 1 such as a Si substrate (its surface is parallel to the XY plane) as a substrate that transmits infrared rays, and a plurality of thermal radiation detection effective provided on the substrate 1. An element 101 and a plurality of thermal radiation detection invalid elements 102 provided on the substrate 1 are provided. Although not shown in the drawing, in the present embodiment, infrared rays are incident from the back side of the paper surface in FIG. 1 to the front side of the paper surface, and the reading light is incident from the front side of the paper surface in FIG. 1 to the back side of the paper surface. It has become.

In this embodiment, as shown in FIG. 1, a plurality of effective elements 101 are two-dimensionally arranged in a rectangular effective element region on the substrate 1. Multiple invalid elements 102
Are arranged in a plurality of rows all around the effective element. However, the arrangement and number of the elements 101 and 102 are not limited to this example. For example, the radiation detection device 1
When 00 is used as an infrared point sensor, the number of elements 101 and 102 may be one each.

FIG. 2 shows a thermal radiation detection effective element 1 in FIG.
It is a schematic plan view which shows an example of 01 typically. 3 is a schematic sectional view taken along line X1-X2 in FIG. 2, and FIG. 4 is a schematic sectional view taken along line X3-X4 in FIG. However, FIGS. 2 to 4 show the radiation detecting apparatus 100 according to the present embodiment.
2 shows a state before the sacrifice layer 20 is removed during the manufacture of. The sacrificial layer 20 is shown in FIGS. 3 and 4, but is omitted in FIG. This sacrificial layer 20 is
Finally, it is removed by ashing or the like. Although not shown in the drawing, the schematic cross-sectional view taken along line X5-X6 in FIG. 2 is similar to FIG. 4, and the schematic cross-sectional view taken along line X7-X8 in FIG. 2 is similar to FIG. . For convenience of explanation,
As shown in FIG. 2, the directions of + X direction and −X direction opposite to each other along the X-axis direction are defined.

FIGS. 5A to 5C are views schematically showing the completed state of the effective element 101 shown in FIG. 2 after the sacrifice layer 20 is removed, and arrows X9-X10 in FIG. It corresponds to the view. FIG. 5A shows a state in which the thermal equilibrium is reached and the temperatures of the substrate and each part of the element are also T0 when the environmental temperature is T0 in a state where the infrared ray i from the target object is not incident. ing. FIG. 5B shows that when the infrared temperature i from the target object is not incident and the environmental temperature is T1 (T1 ≠ T0), thermal equilibrium is reached and the temperatures of the substrate 1 and the entire element are also T1. It shows how it looks. In FIG. 5C, the ambient temperature and the substrate temperature are T
In the case of 0, the infrared ray i from the target object is incident. Note that, in order to facilitate understanding, in FIG. 5, the curved states of the displacement portions 5 and 9 are exaggerated.

The effective element 101 shown in FIG. 2 includes a supported portion 2 supported by a substrate 1 and infrared ray shielding films 13, 1 described later.
4 and. The supported portion 2 is supported in a floating state on the substrate 1 via the two leg portions 3 and 4 which stand up from the substrate 1 in the Z-axis direction (vertical direction). The supported portion 2 includes two first displacement portions 5 and 6, two heat separation portions 7 and 8 having high thermal resistance, and two second displacement portions 9 and 10.
An infrared absorbing section 11 that receives infrared rays i and converts it into heat, and a displacement reading member used to obtain a predetermined change according to the displacement generated in the second displacement sections 9 and 10 of the supported section 2, A reflector 12 for reflecting the received read light,
have.

The effective element 101 shown in FIG. 2 is constructed symmetrically with respect to FIG. 2, and the leg portion 4, the first displacement portion 6, the heat separation portion 8 and the second displacement portion 10 are respectively the leg portion 3, the third portion. The first displacement portion 5, the heat separation portion 7, and the second displacement portion 9 correspond to the leg portion 4, the first displacement portion 6, the heat separation portion 8, and the second displacement portion 9.
The description of the displacing section 10 will be omitted. Effective element 1 shown in FIG.
In 01, in order to obtain mechanical structural stability, the legs,
Two sets of the first displacement part, the heat separation part, and the second displacement part are provided, but the number of the sets may be one or more.

The first displacement portion 5 is in the Z-axis direction (vertical direction).
Is formed of two films (layers) 21 and 22 that are overlapped with each other, and one end portion (starting point portion) thereof is connected to the leg portion 3. Therefore, the first displacement portion 5 is
It is mechanically continuous without the interposition of the heat separation section 7. In the stage where the sacrificial layer 20 is not removed, the first displacement portion 5 is held by the sacrificial layer 20 and is not curved and extends straight in the X-axis direction parallel to the substrate 1 as shown in FIG. There is.

The membrane 21 and the membrane 22 are made of different materials having different expansion coefficients, and the first displacement portion 5 has a so-called bi-material element.
Also called. ) Is composed. Therefore, the sacrificial layer 20
When the first displacement portion 5 receives heat and rises in temperature after completion of removal, when the expansion coefficient of the lower film 21 is smaller than the expansion coefficient of the upper film 22 depending on the temperature. Bends downward (or reduces the amount of bending upwards),
In the opposite case, it bends upward (or the degree of downward bending decreases). In the effective element 101 shown in FIG. 2, the lower film 21 is made of a SiN film, and the upper film 22 is made of an Al film (its expansion coefficient is larger than that of the SiN film). When the temperature of the member 5 is increased by receiving heat, the member 5 bends downward (or the degree of upward bending decreases) depending on the temperature.

In the effective element 101 shown in FIG. 2, the leg portion 3
Is the SiN film 21 and A constituting the first displacement portion 5.
The I film 22 is formed by continuously extending as it is, and the thermal resistance of the leg portion 3 is extremely small. As described above, it is preferable that the thermal resistance of the leg portion 3 is small.
May have a high heat resistance by, for example, being composed only of a material having a high heat insulating property.

The other end (end point) of the first displacement portion 5 is
It is connected to one end of the heat separating section 7. The direction from the start point portion to the end point portion of the first displacement portion 5 is the + X direction. The heat separating portion 7 is made of a material having a high heat insulating property, and is made of a SiN film in this example. Heat separation part 7
Is L mainly extending in the X-axis direction and then slightly extending in the Y-axis direction.
It has a letter shape. In the figure, 3a and 4a indicate contact portions of the leg portions 3 and 4 on the substrate 1, respectively.

One end (starting point) of the second displacement section 9 is connected to the other end of the heat separating section 7. As a result, the second displacement portion 9 is mechanically continuous with the substrate 1 via the heat separation portion 7 and the first displacement portion 5. Second
In the stage where the sacrificial layer 20 is not removed, the displacement portion 9 is held by the sacrificial layer 20 and is not curved and extends straight in the X-axis direction parallel to the substrate 1 as shown in FIG. The other end portion (end point portion) of the second displacement portion 9 is the reflection plate 1
Connected to 2. The direction from the starting point portion to the ending point portion of the second displacement portion 9 is the −X direction. This direction is opposite to the direction from the starting point portion to the ending point portion of the first displacement portion 5.

The second displacing portion 9 is composed of two films (layers) 23 and 24 which are overlapped with each other in the Z-axis direction (vertical direction), like the first displacing portion 5, and has a bimorph structure (bi- mat
Also called erial element. ) Is composed. In the effective element 101 shown in FIG. 2 to FIG. 4, the two layers 21 and 22 of the first displacement portion 5 and the two layers 23 and 24 of the second displacement portion 9 have the same substances constituting each layer. In addition, the overlapping order of layers of each substance is the same. In particular,
The film 23 under the second displacement portion 9 is a SiN film, like the film 21 under the first displacement portion 5. The film 24 on the upper side of the second displacement portion 9 is the film 22 on the upper side of the first displacement portion 5.
Like the above, it is an Al film.

In the effective element 101 shown in FIGS. 2 to 4,
As shown in FIG. 2, the length L1 from the start point portion to the end point portion of the first displacement portion 5 and the length L2 from the start point portion to the end point portion of the second displacement portion 9 are substantially equal. Has been done. Further, the film thicknesses of the films 21 and 23 below the displacement portions 5 and 9 are substantially equal to each other, and the films 22 and 2 above the displacement portions 5 and 9 are substantially the same.
The film thicknesses of 4 are also substantially the same.

Further, in the effective element 101 shown in FIG. 2, the reflection plate 12 is made of an Al film. The infrared absorption section 11 is composed of an infrared absorption film such as gold black, and is used as the reflection plate 1.
2 is formed on the lower surface. Therefore, in the present example, the infrared absorbing section 11 includes the second displacing section 9 via the reflecting plate 12.
Is thermally coupled to. As a result, the infrared absorption section 1
1 is a heat separation part 7 and a first displacement part 5 with respect to the substrate 1.
Are mechanically continuous through.

In the effective element 101 shown in FIG. 2, infrared rays i
Is incident from the lower side of the substrate 1, but this infrared ray i
Infrared ray shielding films 13 and 14 made of an Al film or the like are formed on the substrate 1 below the first displacement portions 5 and 6 as shielding portions that shield the displacement portions 5 and 6. Therefore, the SiN which is the lower film 21 of the first displacement parts 5 and 6
Although the film has an infrared absorbing property, it does not cause a decrease in detection sensitivity. However, the infrared light shielding films 13 and 14 do not necessarily have to be formed. Further, since the heat separating portions 7 and 8 are made of the SiN film having infrared absorbing property, the light shielding films 13 and 14 can extend below the portion, but it is not always necessary to shield this portion. .

Further, in this example, as shown in FIGS. 2 to 4, when the first and second displacement parts 5 and 9 are not curved, the first and second displacement parts 5 are formed. , 9, the heat separating section 7, the infrared absorbing section 11, and the reflecting plate 12 are located in the same layer one step higher than the surface of the substrate 1.

In the effective element 101 shown in FIG. 2, the two films 21 and 22 of the first displacement portion 5 and the second displacement portion 9 are arranged.
The two films 23 and 24 are simultaneously formed for each corresponding layer. That is, the lower film 21 of the first displacement portion 5 and the lower film 23 of the second displacement portion 9 can be simultaneously formed, and thereafter, the upper film 22 of the first displacement portion 5 and the second film of the second displacement portion 9 can be formed. It has a structure capable of simultaneously forming the upper film 24 of the displacement portion 9.

When the sacrificial layer 20 is finally removed, the holding by the sacrificial layer 20 is released, so that the first and second displacement portions 5 and 9 are each film 21 which is determined by the conditions of film formation during manufacturing. The internal stress of .about.24 causes the initial bending.
Now, the environmental temperature at this time (for example, a predetermined room temperature) is T0.
And the temperature of the substrate 1 and each part of the element reaches T after the thermal equilibrium is reached.
If it is 0, the first and second displacement parts 5, 9
Since the temperature of is the same T0, the reflector 12 is parallel to the substrate 1 as shown in FIG.

Next, consider the case where the environmental temperature changes from T0 to T1 as shown in FIG. 5 (b). When thermal equilibrium is reached and the temperatures of the substrate 1 and the entire element reach T1, the temperatures of the first and second displacement parts 5 and 9 also become T1. Therefore, as shown in FIG. 5B, the angles θ1 and θ2 change as compared with the case of FIG. However, even in this case, the angles θ1 and θ2 are the same because the dimensions L1 and L2 are equal. For this reason,
The reflector 12 remains parallel to the substrate 1. That is, if only the environmental temperature (or the substrate temperature) changes, the end point of the second displacement portion 9 and the reflection plate 12 remain parallel to the substrate.

Although this explanation is a theoretical explanation, in reality, due to manufacturing variations and the like, the dimensions L1 and L2 are not always equal. The angle may change.

On the other hand, from the state shown in FIG. 5A, consider the case where the element is irradiated with infrared rays i from the target object, as shown in FIG. 5C. When the infrared ray i is irradiated from the back surface of the substrate 1, the infrared ray i passes through the substrate 1, is absorbed by the infrared absorbing section 11, and is converted into heat. Since the heat separating unit 7 controls the flow of heat, this heat is transmitted to the second displacing unit 9, and the temperature of the second displacing unit 9 rises by an amount corresponding to the incident infrared ray amount, for example, the temperature T2. Rise to. In addition, the amount of heat generated in the infrared absorbing portion 11 flowing into the first displacement portion 5 and the amount of heat flowing out of the first displacement portion 5 to the substrate 1 are substantially equal to each other. The temperature of 5 does not rise. The infrared ray i is shielded by the infrared ray shielding film 11 and does not reach the first displacement portion 5. Therefore,
The first displacement portion 5 does not increase in temperature and maintains the temperature T0.

In this state, the first and second displacement parts 5,
Since there is a temperature difference between 9 and 9, the angles θ1 and θ2
Are different from each other. Therefore, as shown in FIG. 5C, the angle θ3 formed by the end point of the second displacement portion 9 with respect to the substrate 1, that is, the angle θ of the reflection plate 12 with respect to the substrate 1.
3 does not become 0 degree, and the reflection plate 12 is inclined with respect to the substrate 1.
The temperature T2 of the second displacement portion 9 depends on the amount of incident infrared rays, and the angle θ3 depends on the temperature T2 of the second displacement portion 9. Therefore, the angle θ3 reflects the incident infrared ray amount, and the incident infrared ray amount can be detected as the tilt angle θ3 of the reflecting plate 12.

FIG. 6 is a schematic plan view schematically showing an example of the thermal radiation detection ineffective element 102 in FIG. 1 which can be used together with the thermal radiation detection effective element 101 shown in FIG. In FIG. 6, elements that are the same as or correspond to the elements in FIG. 2 are assigned the same reference numerals, and duplicate descriptions thereof will be omitted.

The ineffective element 102 shown in FIG. 6 has substantially the same structure as the effective element 101 shown in FIG. 2, but is constructed so as not to respond to the infrared ray i which is about to enter. Specifically, the ineffective element 102 shown in FIG. 6 is different from the effective element 101 shown in FIG. 2 in place of the light-shielding films 13 and 14 below the entire supported portion 2 (that is, in the infrared absorbing portion 11). The infrared light shielding film 51 such as an Al film is formed on the substrate 1 (including the lower part), and the contact portions 3a and 4a of the legs 3 and 4 are in contact with the light shielding film 51. In other respects, the reactive element 1 shown in FIG.
02 is also configured exactly the same as the effective element 101 shown in FIG. Therefore, the invalid element 102 shown in FIG. 6 operates in exactly the same manner as the effective element 101 shown in FIG. 2 except that it does not respond to the incident infrared ray i.

The thermal radiation detection ineffective element 10 in FIG. 1 which can be used together with the effective element 101 shown in FIG. 2 described above.
As another example of No. 2, although not shown in the drawing, an element obtained by removing the infrared absorption section 11 from the effective element 101 shown in FIG. 2 can be cited. This invalid element 102 is also
Except that it does not respond to the incident infrared ray i, it operates exactly the same as the effective element 101 shown in FIG.

FIG. 7 shows a thermal radiation detection effective element 1 in FIG.
It is a schematic plan view which shows the other example of 01 typically. In FIG. 7, elements that are the same as or correspond to the elements in FIG. 2 are assigned the same reference numerals, and duplicate descriptions thereof will be omitted. The effective element 101 shown in FIG. 7 is different from the effective element 101 shown in FIG. 2 in that the first displacement parts 5 and 6, the infrared ray shielding films 13 and 4 are removed, and the heat separating parts 7 and 8 are replaced by legs. Only the points 57 and 58 are provided. The leg portions 57 and 58 have the same shape as the heat separating portions 7 and 8 and are made of the same material in a plan view. However, the leg portions 57 and 58 extend in an L shape after rising from the substrate 1, Each is connected.
In FIG. 7, 57a and 58a are the substrates 1 in the legs 3 and 4.
The contact portions to the top are respectively shown.

According to the effective element 101 shown in FIG. 7,
The displacement portions 9 and 10 are curved according to the amount of the infrared rays i that have entered the infrared absorption portion 11 from the back side of the paper surface in FIG.
2 leans. In addition, in the effective element 101 shown in FIG.
Unlike the effective element 101 shown in FIG. 3, it does not have a special structure for reducing the amount of displacement with respect to the ambient temperature, and when the ambient temperature changes, the inclination of the reflector 12 fluctuates relatively correspondingly.

FIG. 8 is a schematic plan view schematically showing an example of the thermal type radiation detection ineffective element 102 in FIG. 1 which can be used together with the thermal type radiation detection effective element 101 shown in FIG. In FIG. 8, elements that are the same as or correspond to the elements in FIG. 7 are assigned the same reference numerals, and overlapping descriptions thereof will be omitted.

The ineffective element 102 shown in FIG. 8 has substantially the same structure as the effective element 101 shown in FIG. 7, but is constructed so as not to respond to the infrared ray i which is about to enter. Specifically, the ineffective element 102 shown in FIG. 8 is different from the effective element 101 shown in FIG. 7 on the substrate 1 below the entire supported portion 2 (that is, below the infrared absorbing portion 11). An infrared ray shielding film 52 such as an Al film is formed,
Further, it is only that the contact portions 57a and 58a of the leg portions 57 and 58 are in contact with the light shielding film 52. In other respects, the ineffective element 102 shown in FIG. 8 is also configured exactly the same as the effective element 101 shown in FIG. Therefore, according to the ineffective element 102 shown in FIG.
It operates in exactly the same way as the effective element 101 shown in FIG. 7 except that it does not respond to.

The thermal radiation detection ineffective element 10 in FIG. 1 which can be used together with the effective element 101 shown in FIG. 7 described above.
As another example of No. 2, although not shown in the drawing, an element obtained by removing the infrared absorption section 11 from the effective element 101 shown in FIG. 7 can be cited. This invalid element 102 is also
Except that it does not respond to the incident infrared ray i, it operates exactly the same as the effective element 101 shown in FIG.

In the radiation detecting apparatus 100 according to the present embodiment described above, the film formation and patterning, the sacrifice layer formation and removal, etc. can be performed regardless of which of the above-described configurations is adopted as the elements 101 and 102. It can be manufactured using semiconductor manufacturing technology.

Here, an example of an imaging device using the radiation detection device 100 according to this embodiment will be described with reference to FIG. FIG. 9 is a schematic configuration diagram showing this visualization device.

In addition to the radiation detecting device 100, this imaging device includes a reading optical system and a two-dimensional CC as an image pickup means.
D30 and the infrared rays i from the heat source 31 as an observation target (target object) are condensed to form an infrared image of the heat source 31 on the surface on which the infrared absorption section 11 of the radiation detection apparatus 100 is distributed. And an image forming lens 32 for infrared rays.

In this imaging device, the readout optical system is an LED 33 as a readout light supply means for supplying readout light, and the readout light from the LED 33 is reflected by all the elements 101 and 102 of the radiation detection device 100. The first lens system 34 guided to the plate 12 and a desired light beam bundle among the light beam bundles of the reading light reflected by the reflection plates 12 of all the elements 101 and 102 after passing through the first lens system 34 are selectively selected. And the first lens system 34 in cooperation with the light flux limiting portion 35 that passes the light flux limiting portion 35 to form a position conjugate with the reflection plate 12 of each of the elements 101 and 102, and the light flux limiting portion 3 at the conjugate position.
And a second lens system 36 that guides the bundle of rays that has passed through 5. The light receiving surface of the CCD 30 is arranged at the conjugate position, and the reflecting plates 12 of all the elements 101 and 102 and the light receiving surface of the CCD 30 are optically conjugated by the lens systems 34 and 36.

The LED 33 has an optical axis O of the first lens system 34.
Is arranged on one side (right side in FIG. 9) with respect to
The reading light is supplied so that the reading light passes through the region on the one side. In this example, the LED 33 is arranged in the vicinity of the focal plane on the second lens system 36 side of the first lens system 34, and the read light that has passed through the first lens system 34 becomes a substantially parallel light flux and all the elements 101, 102 are connected. The reflection plate 12 is irradiated. In order to enhance the contrast of the optical image on the CCD 30, a reading light diaphragm may be provided in front of the LED 33. In this example, the radiation detection device 100
Are arranged so that the surface of the substrate 1 (in this example, parallel to the surface of the film 12 as a reflection portion when infrared rays do not enter) is orthogonal to the optical axis O. However, the arrangement is not limited to this.

The ray bundle limiting section 35 is arranged such that a portion for selectively passing only the desired ray bundle is located on the other side (left side in FIG. 9) with respect to the optical axis O of the first lens system 34. Is configured. In this example, the light flux limiting unit 35
Is composed of a light shielding plate having an opening 35a and is configured as an aperture stop. In this example, any effective element 101
When the infrared ray is not incident on the infrared absorbing section 11 of the heat source 31 and the reflection plates 12 of all the elements 101 and 102 are parallel to the substrate 1, the infrared rays are reflected by the reflection plates 12 of all the elements 101 and 102. The light flux limiting unit 35 is arranged so that the light flux (the bundle of individual light fluxes reflected by each reflecting plate 12) is focused by the first lens system 34 at the position of the focal point and the position of the opening 35a. It is arranged. Also, the opening 3
The size of 5a is determined so as to substantially match the size of the cross section of this bundle of rays at the converging point. However,
The arrangement and size are not limited to this.

According to the imaging device shown in FIG. 9, the LED 3
The light beam bundle 41 of the readout light emitted from 3 enters the first lens system 34 and becomes a substantially parallel light beam bundle 42. Next, the substantially collimated light beam 42 is transmitted to the radiation detection device 1
The light is incident on the reflectors 12 of all the elements 101 and 102 of No. 00 at a certain angle with respect to the normal line of the substrate 1.

On the other hand, the heat source 31 is formed by the imaging lens 32.
The infrared light from the heat source 31 is collected, and an infrared image of the heat source 31 is formed on the surface of the radiation detecting device 100 where the infrared absorbing parts 11 are distributed. As a result, infrared rays enter the infrared absorption section 11 of each of the elements 101 and 102 of the radiation detection apparatus 100. The incident infrared rays are reflected by the reflection plate 1 of each effective element 101.
Converted to a slope of 2. On the other hand, the incident infrared rays do not change the inclination of the reflection plate 12 of each ineffective element 101.

Now, it is assumed that infrared rays from the heat source 31 are not incident on the infrared ray absorbing portions 11 of all the effective elements 101, and the reflection plates 12 of all the elements 101 and 102 are parallel to the substrate 1. Reflector 12 of all elements 101, 102
The light beam bundle 42 which is incident on is reflected by these reflecting plates 12 to become a light beam bundle 43, which again enters the first lens system 34 from the side opposite to the LED 33 side and converges the light flux 4
4, the light beam 44 is condensed at the position of the opening 35a of the light flux limiting portion 35 arranged at the position of the light condensing point. As a result, the condensed light flux 44 is transmitted through the opening 35a and becomes a divergent light flux 45 and enters the second lens system 36. The divergent light beam 45 that has entered the second lens system 36 becomes, for example, a substantially parallel light beam 46 by the second lens system 36 and enters the light receiving surface of the CCD 30. Here, the reflector 1 of each of the elements 101 and 102
2 and the light-receiving surface of the CCD 30 have a conjugate relationship with each other by the lens systems 34 and 36, so that the reflecting plates 12 of the elements 101 and 102 are provided at the corresponding portions on the light-receiving surface of the CCD 30, respectively.
Image is formed, and as a whole, all the elements 101, 10
An optical image that is a distribution image of the second reflection plate 12 is formed.

Now, a certain amount of infrared rays are incident from the heat source 31 on the displacement portion 9 of a certain effective element 101, and the reflection plate 12 of the effective element 101 is moved relative to the surface of the substrate 1 by an amount corresponding to the incident amount. It shall be inclined. The individual ray bundles of the ray bundles 42 that are incident on the reflecting plate 12 are reflected by the reflecting plate 12 in directions different from each other by the amount of inclination thereof, and therefore, after passing through the first lens system 34, the individual ray bundles are changed according to the amount of inclination. The light flux limiting unit 3 focuses the light at a position deviated from the position of the light condensing point (that is, the opening 35a) by an amount, and an amount corresponding to the amount of inclination.
It will be blocked by 5. Therefore, the CCD 30
The light amount of the image of the reflection plate 12 of the effective element 101 in the entire optical image formed above is reduced by an amount corresponding to the tilt amount of the reflection plate 12. On the other hand, the inclination of the reflection plate 12 of the ineffective element 102 does not change depending on the incident amount of infrared rays, but changes, for example, due to a change in environmental temperature.

Therefore, the optical image of the reflection plate 12 of the effective element 101 formed by the reading light formed on the light receiving surface of the CCD 30 reflects the infrared image incident on the radiation detecting apparatus 100. On the other hand, the optical image of the reflection plate 12 of the ineffective element 102 formed by the readout light formed on the light receiving surface of the CCD 30 does not reflect the incident infrared image,
For example, it reflects the fluctuation amount of the environmental temperature. These optical images are picked up by the CCD 30.

Needless to say, the structure of the reading optical system is not limited to the above-mentioned structure.

Further, the imaging device shown in FIG. 9 detects the amount of light emitted from the LED 33, which is the light source of the readout light, and the amount of light emitted from the LED 33 (that is, the readout amount based on the detection signal from the light amount sensor 60). Light intensity)
Feedback control to keep the LED constant
And a drive control circuit 61 for driving the. Therefore, even if the characteristics of the LED 33 change due to changes in the environmental temperature, the light amount of the read light does not change and is stably kept constant.

Further, the imaging device shown in FIG. 9 has a signal processing unit 62 composed of, for example, a microcomputer or the like.
And an image memory 63 and a memory 64.

An example of the operation of the signal processing section 62 will be described with reference to FIG. FIG. 10 is a schematic flowchart showing an example of the operation of the signal processing unit 62. When the signal processing unit 62 starts its operation, first, it fetches an initial image from the CCD 30 and stores it in the image memory 63 (step S1). Next, the signal processing unit 62 determines the predetermined invalid element 102 in the initial image data captured in step S1.
Brightness value of the image of the reflection plate 12 (for example, a plurality of ineffective elements 1
The average value of the brightness values of the image of the reflection plate 12 of No. 02 may be used. )
Is stored in the memory 64 as the initial output of the invalid element 102 (step S2).

Next, the signal processor 62 proceeds to step S1.
Each invalid element 1 based on the initial image data captured in
The position of the reflection plate 12 of No. 02 is calculated, and the position data is stored in the memory 64 as initial position data (step S
3).

Thereafter, the signal processing section 62 determines whether or not a new image is obtained from the CCD 30 (step S
4) If not, wait until a new image is obtained. When a new image is obtained from the CCD 30, the signal processor 62 receives this image (the reflection plate 12 of the elements 101 and 102).
(The image showing the optical image of) is stored in the image memory 63 (step S5).

Next, the signal processing unit 62 outputs the luminance value of the image of the reflection plate 12 of the predetermined invalid element 102 (current output) in the latest image data captured in step S5.
And the invalid element 10 stored in the memory 64 in step S2.
The difference (output difference) from the initial output (luminance value) of 2 is calculated (step S6). After that, the signal processing unit 62 calculates the output difference calculated in step S6 from the brightness value (current output) of the image of the reflection plate 12 of each effective element 101 among the image data most recently captured in step S5. Then, the level of the image data by each effective element 101 is adjusted (step S7).

Next, the signal processor 62 proceeds to step S5.
Each invalid element 1 in the image data that was captured most recently
The position (current position) of the image of the reflection plate 12 of No. 02 is calculated (step S8). Thereafter, the signal processing unit 62 adjusts the level in step S7 based on the current position of each invalid element 102 calculated in step S8 and the initial position of each invalid element 102 stored in the memory 64 in step S3. Corrected image data is obtained by performing image transformation processing on the image data obtained by each effective element 101 so that the current position returns to the initial position (step S10).

After that, the signal processor 62 proceeds to step S1.
The corrected image data obtained at 0 is output, and the process returns to step S4.

In the imaging device shown in FIG. 9, the light quantity of the read-out light is kept constant without changing as described above.
In the radiation detection device 100 used in the imaging device shown in FIG. 9, the ineffective element 102 is the effective element 101.
It has substantially the same structure as and does not respond to incident radiation. Therefore, the reactive element 102 performs the same operation as the effective element 101 with respect to the fluctuation of the environmental temperature, but does not respond to the incident radiation. Therefore, the invalid element 102
The output fluctuation (the output difference calculated in step S6) obtained from the above corresponds to the output fluctuation (offset fluctuation component) of the effective element 101 due to the environmental temperature. Therefore,
In the imaging apparatus shown in FIG. 9, since the output fluctuation obtained from the invalid element 102 is removed from the output obtained from each effective element 101 in the step S7,
The corrected image output from the signal processing unit 62 has a reduced influence of environmental temperature variations, and the image quality is improved.

When a deviation occurs in the above-mentioned components of the reading optical system due to vibration, shock, thermal expansion, etc., the CCD
The image obtained from 30 undergoes fluctuations such as rotation, distortion, and fluctuations in magnification, which deteriorates the image quality. However, in the imaging device shown in FIG. 9, the initial position and the current position on the image of the ineffective element 102 arranged so as to surround the area of the effective element 101 are obtained (steps S3 and S8), and based on these, Correction is performed (step S9). Therefore, the corrected image output from the signal processing unit 62 has been corrected for the rotation, distortion, magnification variation, and the like,
From this point as well, the image quality is improved. The invalid element 102
Since the output from is independent of the amount of incident infrared rays, the correction can always be appropriately performed regardless of the amount of incident infrared rays.

In FIG. 10, steps S2 and S
6, S7 may be removed. Even in this case, it is possible to obtain the advantage that the rotation, the distortion, the variation in the magnification, and the like can be corrected. Further, in FIG. 10, steps S3, S8 and S9 may be omitted. in this case,
In step S10, the image data whose level has been adjusted in step S7 may be output as corrected image data. Even in this case, it is possible to obtain the advantage of being able to reduce the influence of the fluctuation of the environmental temperature.

By the way, the imaging apparatus shown in FIG. 9 may be modified as follows. In this modified example, the light amount sensor 60 in FIG. 9 is removed, and instead of the drive control circuit 61, LE is used.
A drive circuit that simply turns on D33 is used. Therefore, the amount of read light emitted from the LED 33 varies depending on the environmental temperature. Further, in this modified example, the radiation detection apparatus 100 is housed in a container (not shown), a temperature controller such as a Peltier element is used, and this is strictly controlled with high responsiveness.
Make sure that the outputs of 1, 102 do not fluctuate.

In this modification, the signal processor 62
However, instead of the operation shown in FIG. 10, the operation shown in FIG. 11 is performed. The operation shown in FIG. 11 differs from the operation shown in FIG. 10 only in that steps S6 and S7 in FIG. 10 are replaced with steps S20 and S21. In step S20, the signal processing unit 62 sets the brightness value (current output) of the image of the reflection plate 12 of the predetermined invalid element 102 among the image data captured most recently in step S5 and the memory 64 in step S2. The ratio (output ratio) with respect to the initial output (luminance value) of the invalid element 102 stored in FIG. In step S21, the signal processing unit 62
Of the image data captured most recently in step S5,
The brightness value (current output) of the image of the reflector 12 of each effective element 101 is multiplied by the output ratio calculated in step S20 to adjust the level of the image data by each effective element 101.

In this modification, the fluctuation of the light quantity of the reading light appears as the fluctuation of the gain of the signal in the image signal obtained from the CCD 30. In this modification, as described above, the elements 101, 10 may be changed depending on the environmental temperature.
No change occurs in the output of 2. Therefore, the invalid element 10
The output fluctuation obtained from 2 (the output ratio calculated in step S20) is the effective element 1 due to the fluctuation of the light quantity of the reading light.
This corresponds to the output gain fluctuation of 01. Therefore, in this modified example, since the output gain fluctuation obtained from the invalid element 102 is removed from the output obtained from each effective element 101 in the step S21, the corrected image output from the signal processing unit 62 is executed. Means that the influence of the fluctuation of the light amount of the reading light is reduced, and the image quality is improved.

Further, this modification also has an advantage that the rotation, the distortion, the variation of the magnification, and the like can be corrected, as in the imaging device shown in FIG. In addition, in FIG. 11, steps S3, S8, and S9 may be omitted. In this case, in step S10, the image data whose level has been adjusted in step S21 may be output as corrected image data. Even in this case, it is possible to obtain the advantage that it is possible to reduce the influence of the fluctuation of the light amount of the reading light.

Although the above is an example of the imaging device, in FIG. 9, as the radiation detection device 100, a radiation detection device having only one effective element 101 and one invalid element 102 is used, and the two-dimensional CCD 30 is replaced. Thus, by using a photodetector having only two light receiving portions, it is possible to configure a detection device as a so-called point sensor for infrared rays.

Although one embodiment and modification of the present invention have been described above, the present invention is not limited to these. For example, the present invention can be applied not only to an optical readout type thermal radiation detection device but also to a capacitance type thermal infrared detection device.

[0075]

As described above, according to the present invention,
Not only the thermal radiation detection effective element, but because the thermal radiation detection invalid element is provided, signal processing for reducing the influence of the environmental temperature, signal processing for reducing the influence of the light amount fluctuation of the light source, It is possible to provide a thermal radiation detection device capable of appropriately performing image correction processing and the like.

[Brief description of drawings]

FIG. 1 is a schematic plan view schematically showing an optical readout type thermal radiation detection device according to an embodiment of the present invention.

FIG. 2 is a schematic plan view schematically showing an example of the thermal radiation detection effective element in FIG.

FIG. 3 is a schematic sectional view taken along line X1-X2 in FIG.

FIG. 4 is a schematic sectional view taken along line X3-X4 in FIG.

5 is a diagram schematically showing a completed state of the thermal radiation detection effective element shown in FIG. 2 after removing a sacrifice layer.

6 is an example of a thermal radiation detection invalid element in FIG. 1 which can be used with the thermal radiation detection effective element shown in FIG.
It is a schematic plan view which shows typically.

7 is a schematic plan view schematically showing another example of the thermal radiation detection effective element in FIG.

8 is an example of a thermal radiation detection invalid element in FIG. 1 which can be used with the thermal radiation detection effective element shown in FIG.
It is a schematic plan view which shows typically.

FIG. 9 is a schematic configuration diagram showing the thermal radiation detection device shown in FIG.

FIG. 10 is a schematic flowchart showing an example of the operation of the signal processing unit.

FIG. 11 is a schematic flowchart showing another example of the operation of the signal processing unit.

[Explanation of symbols]

1 substrate 2 Supported part 3,4 legs 5,6 First displacement part 7,8 Heat separation part 9,10 Second displacement part 12 Reflector 100 Thermal radiation detector 101 Thermal radiation detection effective element 102 Thermal radiation detection invalid element

Claims (3)

[Claims] 1. A base, at least one thermal radiation detection effective element provided on the base, and at least one thermal radiation detection ineffective element provided on the base. The thermal radiation detection effective element is a supported portion supported by the base body, and a radiation absorption portion that receives radiation and converts it into heat, and a radiation absorption portion for the base body according to the heat generated in the radiation absorption portion. A supported portion having a displacement portion that is displaced according to the displacement and a displacement reading member that is used to obtain a predetermined change according to the displacement generated in the displacement portion, wherein the at least one thermal radiation detection ineffective element is A thermal-type radiation detecting device, which has substantially the same structure as the thermal-type radiation-detecting effective element, but is configured not to respond to incident radiation. 2. The at least one thermal-type radiation detection-ineffective element has a shielding portion that blocks incidence of the radiation on a radiation-absorption portion of the thermal-type radiation detection-ineffective element. Thermal radiation detector. 3. The thermal radiation detection device according to claim 1, wherein the at least one thermal radiation detection ineffective element has no radiation absorption section.