JP2002188964A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To acquire a natural image. SOLUTION: Reflection parts 9 of all pixels of a radiation-displacement conversion device 100 are irradiated with readout light through a first lens system 11. Reflected light from the reflection parts 9 of each pixel passes the first lens system 11 again and forms a spot on a ray bundle restriction part 12. The shape of a ray bundle passing part 12a of the ray bundle restriction part 12 is set so that the change of the quantity of light at the position on a CCD 20 conjugated with the reflection part 9 relative to the change of inclination of each reflection part 9 is not reversed. Light passing the passing part 12a of the ray bundle restriction part 12 is guided to the CCD 20 through a second lens system 13. The reflection plate 9 and the CCD 20 are conjugated each other by the first and the second lens systems 11, 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device for converting radiation such as infrared rays reaching a predetermined range into an optical image.

[0002]

2. Description of the Related Art The present inventors convert radiation such as infrared rays into heat, convert the heat into displacement, read the displacement with a reading light using a reading optical system, and reach a predetermined range. An imaging device for converting radiation into an optical image was invented (Japanese Patent Application Laid-Open Nos.
No. 28437).

In such an imaging apparatus, an optical system for converting the displacement of the displacement unit into a change in the amount of light is used as the readout optical system. As one of the readout optical systems, Japanese Patent Laid-Open No. 2000-28437 discloses the following optical system.

[0004] In this optical system, readout light is applied to a reflecting portion whose inclination changes according to the displacement of the displacement portion, and the light reflected by the reflecting portion is collected. A pinhole plate having a circular pinhole having substantially the same diameter as the spot is provided near the position of the spot (focus point). As a result of the position of the spot moving according to the inclination of the reflecting portion, the area of the spot overlapping the pinhole changes, and the amount of light passing through the pinhole changes. Therefore, the displacement of the displacement section is converted into a change in the amount of light.

[0005]

However, as a result of the research by the present inventors, it has been found that the following inconveniences occur in the imaging apparatus using the above-mentioned conventional optical system.

First, since the conventional imaging apparatus uses a pinhole plate having a circular pinhole having substantially the same diameter as the spot, an obtained image may be unnatural. It turned out to be.

[0007] This point will be described with reference to FIGS. 14 and 15 by taking as an example a case where the radiation is infrared rays and an infrared image is converted into an optical image. FIG. 14 is a diagram showing a state of a spot S0 formed by light reflected by a certain reflection portion on a pinhole plate 80 having a pinhole 80a in a conventional imaging device. In the example shown in FIG. 14, when the temperature of the target object rises (that is, the amount of infrared light incident from the target object increases), the inclination of the reflector changes, and the spot S0 moves rightward in FIG. It has become. The pinhole 80a has a circular shape having substantially the same diameter as the spot S0.

Now, consider a case where the temperature of the target object rises from a low state. The spot S0 first reaches a position where its right side is in contact with the left edge of the pinhole 80a, as shown by the solid line in FIG. Thereafter, the spot S0 starts to overlap with the pinhole 80a, and the area where the spot S0 overlaps with the pinhole 80a gradually increases, and
The passing light amount of 0a gradually increases. Then, when the spot S0 just overlaps the pinhole 80a,
The area where the spot S0 overlaps the pinhole 80a is maximized, and the amount of light passing through the pinhole 80a is maximized. When the temperature of the target object further rises, the area where the spot S0 overlaps the pinhole 80a gradually decreases, and the amount of light passing through the pinhole 80a gradually decreases. Eventually, Figure 1
As shown by the broken line in FIG. 4, even if the left side of the spot S0 reaches a position in contact with the right edge of the pinhole 80a and the temperature of the target object further rises and the spot S0 moves rightward, The passing light amount at 80a remains zero.
Therefore, in the conventional imaging device, as shown in FIG. 15, a change in the temperature of the target object (that is, a change in the amount of incident infrared rays from the target object, and thus, a change in the inclination of the reflecting portion) causes the pinhole 80a to change. The change in the amount of passing light reverses from increasing to decreasing on the way.

Conventionally, only a range in which the amount of transmitted light monotonically increases (for example, a range in FIG. 15) or a range in which the passing light amount monotonously decreases (for example, b in FIG.
It has been considered that it is only necessary to be able to convert the light amount into a light amount corresponding to the temperature of the target object only by using the range (2). Then, when changing the temperature range to be observed, it has been considered that the positional relationship between the pinhole 80a and the spot S0 should be adjusted according to the observed temperature range.

However, actually, there are many objects whose temperature is extremely out of the temperature range to be observed. For example, when the temperature range to be observed is a temperature range near room temperature, the temperature of the sun or a cigarette fire is a very high temperature, which is extremely outside the temperature range around room temperature.

Now, consider a case where an object having a temperature near normal temperature is to be observed, and the temperature range near normal temperature is set to the range a in FIG. In this case, in the observation temperature range near room temperature, the higher the temperature of the target object, the higher the amount of light passing through the pinhole 80a. Therefore, since the temperature of the sun and the like is high, even if an object having a temperature near room temperature is to be observed, the amount of light passing through the pinhole 80a is originally high when infrared rays from the object such as the sun enter. Should. However, since the temperature of the sun and the like is extremely high as shown by c in FIG. 15, when the temperature extremely deviates from the range of a in FIG. 15 and infrared rays from an object such as the sun enter, The amount of light passing through the pinhole 80a becomes zero, and an obtained image becomes unnatural.

Next, a second disadvantage of the conventional imaging apparatus will be described. Although the plurality of reflecting portions are distributed, even in an initial state where radiation such as infrared rays from the target object is not incident, the inclination of each reflecting portion varies due to variation in characteristics of the corresponding displacement portion. Therefore, the positions of the spots due to the respective reflection portions vary. For this reason, in the conventional imaging device, since the pinhole plate having a circular pinhole having substantially the same diameter as the spot is used, the position of the pinhole is adjusted with reference to the spot by a certain reflection portion. Even if it is performed, the movement range of the spot by another certain reflection unit may completely deviate from the position of the pinhole.

FIG. 16 shows an example of this state. In FIG. 16, the same or corresponding elements as those in FIG. 14 are denoted by the same reference numerals, and overlapping description will be omitted. S in FIG.
1 and S2 respectively show spots formed in an initial state in which infrared rays from the target object are not incident on any of the pixels including the respective reflection portions, and S1 is the most in FIG. The spot formed on the left side is shown, and S2 shows the spot formed on the rightmost side. From this state, when the same amount (maximum allowable amount) of infrared rays is incident on all the pixels from the target object, the spots S1 and S2 move rightward to become spots S1 'and S2'. For the spot S2, a change in the overlapping area with the pinhole 80a occurs appropriately. For example, for the spot S1, no change in the overlapping area with the pinhole 80a occurs.

As described above, in the conventional imaging apparatus,
Due to the variation, the spot S1 due to a certain reflection portion
Is completely displaced from the position of the pinhole 80a, so that a pixel including the reflective portion has a situation similar to a pixel defect. Moreover, although not shown in the drawing, since other spots are distributed between the spots S1 and S2, it can be understood that the same situation as a pixel defect occurs in many other spots. . Therefore, in the conventional video apparatus, the image quality of the obtained image is significantly reduced due to the variation.

The present invention has been made in view of the above circumstances, and has as its object to provide an imaging apparatus capable of obtaining a natural image.

Further, according to the present invention, it is possible to reduce the rate of occurrence of pixels which cause the same situation as a pixel defect even if the characteristics of the displacement portion vary, and to improve the image quality of the obtained image. It is intended to provide a device.

[0017]

According to a first aspect of the present invention, there is provided an imaging apparatus for converting radiation arriving within a predetermined range into an optical image. It has a mold radiation-displacement converter and a readout optical system. The light-reading type radiation-displacement converter includes a plurality of radiation absorbers that are arranged at a plurality of locations located within the predetermined range and convert radiation received at the plurality of locations into heat, respectively, and the plurality of radiations. It includes a plurality of displacement units that convert each heat converted by the absorption unit into displacements at positions corresponding to the plurality of locations, and a plurality of reflection units whose inclinations change according to the displacements of the plurality of displacement units. The readout optical system, a readout light supply unit for supplying readout light, a first lens system that guides the readout light to a plurality of reflection units of the light readout type radiation-displacement conversion unit,
A light beam restricting unit that selectively passes only a desired light beam among light beams of the read light reflected by the plurality of reflecting units after passing through the first lens system; And a second lens system that forms a conjugate position with the plurality of reflecting portions and guides the light beam that has passed through the light beam restricting portion to the conjugate position. The reading light supply unit,
The readout light is supplied so that the readout light passes through a region on one side of the optical axis of the first lens system. The light beam restricting unit is configured such that a passage portion for selectively passing only the desired light beam is disposed in a region on the other side with respect to the optical axis of the first lens system. Then, the shape of the passing portion of the light beam restricting portion, the change in the amount of light at a position conjugate with the reflecting portion, with respect to the change in the inclination of each of the reflecting portions, does not reverse.
Is set.

In the first aspect, the shape of the passing portion of the light beam restricting portion is different from that of the conventional imaging device, and the change in the amount of light at a position conjugate to the reflecting portion with respect to the change in the inclination of each reflecting portion. , So that it does not reverse. Therefore, according to the first aspect, there is no possibility that the relationship between the magnitude of the incident radiation and the magnitude of the light amount is reversed, and the obtained image is a natural image.

An imaging device according to a second aspect of the present invention comprises:
In the first aspect, the shape of the light passing portion of the light beam restricting portion may be such that a change characteristic of a light amount at a position conjugate with the reflection portion with respect to a change in inclination of each reflection portion is a monotonous change region and the monotonous change region. The characteristic is set so as to have a characteristic having a continuous area and a continuous area.

According to the second aspect, the change characteristic is a combination of a monotone change region and an invariant region. Therefore, compared to a case where the change characteristic is only a monotone change region, an obtained image can be obtained. A more natural image is obtained.

An imaging device according to a third aspect of the present invention comprises:
In the first or second aspect, the shape of the passing portion of the light beam restricting portion may be such that each spot formed on the light beam restricting portion by the readout light reflected by each of the reflecting portions is the respective spot. Within the range of a predetermined distance along the moving direction in which the reflecting portion moves in accordance with the change in the inclination, the overlapping area or the non-overlapping area with the spot decreases as the spot is located on one side in the moving direction. Or, it is set to be large. The predetermined distance is based on a distribution width in the movement direction due to an initial variation of a plurality of spots respectively formed on the light flux limiting unit by the reading light reflected by the plurality of reflecting units. long. Here, the initial variation refers to a variation in a case where radiation from the target object is not incident on any of the pixels including the respective reflective portions. This is the same for a fourth embodiment described later.

According to the third aspect, the inclination of the plurality of reflecting portions varies due to the variation in the characteristics of the corresponding displacement portions, and the initial variation of the plurality of spots formed on the light beam limiting portion is reduced. Even if it occurs, the number of pixels in which the amount of light reflected by the reflecting portion and passing through the light beam limiting portion does not change at all even though the corresponding displacement portion is displaced is reduced as compared with the related art. Therefore, according to the third aspect,
Even if the characteristics of the displacement portion vary, it is possible to reduce the rate of occurrence of pixels that cause the same situation as a pixel defect, and to improve the image quality of the obtained image.

An imaging device according to a fourth aspect of the present invention comprises:
An imaging device for converting radiation that reaches a predetermined range into an optical image includes an optical readout radiation-displacement conversion unit and a readout optical system. The light-reading type radiation-displacement converter includes a plurality of radiation absorbers that are arranged at a plurality of locations located within the predetermined range and convert radiation received at the plurality of locations into heat, respectively, and the plurality of radiations. It includes a plurality of displacement units that convert each heat converted by the absorption unit into displacements at positions corresponding to the plurality of locations, and a plurality of reflection units whose inclinations change according to the displacements of the plurality of displacement units. The readout optical system includes a readout light supply unit for supplying readout light, a first lens system that guides the readout light to a plurality of reflection units of the optical readout radiation-displacement conversion unit, and a first lens system. A light beam limiting unit that selectively passes only a desired light beam among the light beams of the readout light reflected by the plurality of reflecting units after passing through the first light source unit;
A second lens system that forms a conjugate position with the plurality of reflecting portions in cooperation with the lens system and guides the light beam that has passed through the light beam restricting portion to the conjugate position. The readout light supply unit supplies the readout light so that the readout light passes through a region on one side of the optical axis of the first lens system. The light beam restricting unit is configured such that a passage portion for selectively passing only the desired light beam is disposed in a region on the other side with respect to the optical axis of the first lens system. The shape of the passing portion of the light beam restricting portion is such that each spot formed on the light beam restricting portion by the read light reflected by each of the reflecting portions moves according to a change in the inclination of each of the reflecting portions. Within a range of a predetermined distance along the moving direction, the overlapping area or the non-overlapping area with the spot is set to be smaller or larger as the spot is located on one side in the moving direction. The predetermined distance is longer than the distribution width in the movement direction of the plurality of spots formed on the light flux limiting unit by the readout light reflected by the plurality of reflecting units, respectively, due to an initial variation.

According to the fourth aspect, similarly to the third aspect, even if the characteristics of the displacement portion vary, the rate of occurrence of pixels that are in the same situation as a pixel defect can be reduced. The quality of the obtained image can be improved.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an imaging device according to the present invention will be described with reference to the drawings. In the following description, an example will be described in which the radiation is infrared light and the readout light is visible light. However, in the present invention, the radiation may be X-rays, ultraviolet rays, or other various radiations other than infrared light, May be other light than visible light.

[First Embodiment]

FIG. 1 is a schematic configuration diagram showing an imaging device according to the first embodiment of the present invention. FIG. 2 is a diagram showing an optical readout radiation-displacement conversion device 100 used in the present embodiment. For convenience of explanation, an X axis, a Y axis, and a Z axis that are orthogonal to each other are defined as shown in the drawing.

As shown in FIG. 1, the imaging device according to the present embodiment includes an optical readout radiation-displacement conversion device 100. As shown in FIG. 2, the conversion apparatus 100 includes a substrate 1 such as a silicon substrate that transmits infrared rays i,
And a supported portion 3 supported in a state of floating above the substrate 1 with a space 6 therebetween via the leg portion 2. The supported part 3 is
It has two membranes 4, 5 that overlap each other. On the lower surface of the lower film 4, a film 7 is formed as an infrared absorbing portion that receives infrared rays and converts them into heat. One end of each of the membranes 4 and 5 is supported via the leg portion 2 to form a cantilever. The film 4 and the film 5 are made of different materials having different expansion coefficients from each other, and form a so-called thermal bimorph structure (also referred to as a bi-material element). Therefore, in the present embodiment, the film 4,
Reference numeral 5 denotes a displacement unit that is displaced with respect to the substrate 1 according to heat generated in the film 7. When the expansion coefficient of the lower film 4 is larger than the expansion coefficient of the upper film 5, the film is curved upward by the heat. Here, it is assumed that the plate is bent downward according to the heat. A part of the reflection part 9 is fixed to the tip of the film 5. The remaining portion of the reflection section 9 is disposed above the film 5 with a space therebetween, and covers almost the entire unit pixel. Therefore, the inclination of the reflecting portion 9 changes according to the displacement of the films 4 and 5. As a result, the reflection unit 9 receives the readout light j from above, and reflects the received readout light in a reflection direction according to the displacement of the films 4 and 5.

Although not shown in the drawings, the membranes 4, 5, 7,
The legs 2 and the reflection portions 9 are used as unit pixels (unit elements), and the pixels are two-dimensionally arranged on the substrate 1. The direction in which the supported portion 3 extends from the leg portion 2 in each pixel is the same. The conversion device 100 is arranged in FIG. 1 so that the X, Y, and Z directions in FIG. 1 match the X, Y, and Z directions in FIG.

The conversion apparatus 100 can be manufactured by using semiconductor manufacturing techniques such as formation and patterning of a film and formation and removal of a sacrificial layer.

Referring again to FIG. 1, the imaging apparatus according to the present embodiment collects infrared rays from a readout optical system, a two-dimensional CCD 20 as an image pickup means, and a heat source (target object) 31 as an observation target. An infrared imaging lens 30 for imaging an infrared image of the heat source 31 on the surface of the converter 100 on which the film 7 as an infrared absorbing portion is distributed.

In the present embodiment, the readout optical system includes an LD (laser diode) 10 as a readout light supply unit for supplying readout light, and a plurality of reflection units of the conversion device 100 for reading out the readout light from the LD 10. 9, a first lens system 11 for guiding the light beam to the first lens system 11, and a light beam limiter for selectively passing only a desired light beam among the light beams of the readout light reflected by the plurality of reflection units 9 after passing through the first lens system 11. Unit 12 and the first lens system 11 cooperate with each other to form a conjugate position with the plurality of reflection units 9 and to set the light beam limiting unit 1 at the conjugate position.
And a second lens system 13 for guiding the light beam passing through the second lens system 2. The light receiving surface of the CCD 20 is arranged at the conjugate position. In the present embodiment, the conversion device 1
The reflecting section 9 of 00 is arranged near the focal plane of the first lens system 11 on the side of the imaging lens 30, but is not necessarily limited to such an arrangement.

The LD 10 is disposed on one side (the right side in FIG. 1) with respect to the optical axis O of the first lens system 11, and supplies the reading light so that the reading light passes through the one side area. I do. In the present embodiment, the LD 10 is disposed near the focal plane of the first lens system 11 on the side of the second lens system 13, and the readout light passing through the first lens system 11 is converted into a substantially parallel light flux to form a plurality of reflection units. 9 is illuminated. In the present embodiment, the conversion device 100 includes the substrate 1
(In the present embodiment, parallel to the surface of the reflecting section 9 when infrared rays from the heat source (target object) 31 do not enter) are arranged so as to be orthogonal to the optical axis O. However, it is not limited to such an arrangement.

The light beam restricting section 12 has a passing portion for selectively passing only the desired light beam in an area on the other side (left side in FIG. 1) with respect to the optical axis O of the first lens system 11. It is configured to: In the present embodiment, the light beam restricting unit 12 is configured by a light-shielding plate having an opening 12a and a light-shielding region 12b surrounding the opening 12a, and the opening 12a includes a passage portion that selectively allows only the desired light beam. Has become.

The shape of the opening 12a is set so that a change in the amount of light at a position conjugate with the reflection section 9 with respect to a change in the inclination of the reflection section 9 of each pixel does not reverse. In the present embodiment, the opening 12a is specifically shaped as shown in FIG. FIG. 3 is a diagram illustrating a state of a spot S0 formed by light reflected by a certain reflection unit 9 on the light flux limiting unit 12. In the present embodiment, when the temperature of the target object increases (that is, the amount of infrared light incident from the target object increases), the inclination of the reflector 9 changes, and the spot S0 moves in the X direction. I have. The shape of the opening 12a is an elongated shape extending in the X direction, the width in the Y direction is slightly wider than the diameter of the spot S0, and both sides of the opening 12a in the X direction are semicircular shapes each having a diameter slightly larger than the diameter of the spot S0. Has become.

Since the shape of the opening 12a is such a shape, the change in the temperature of the target object (that is, the change in the amount of incident infrared rays from the target object, and the change in the inclination of the reflection unit 9) causes the change in the reflection unit. The change in the amount of light passing through the light beam restricting unit 12 (the amount of light passing through the opening 12a) after reflecting the light 9 is
As shown in FIG. That is, the passing light amount of the light beam limiting unit 12 is zero when the temperature of the target object is low, gradually increases from a predetermined temperature to a predetermined temperature higher than the predetermined temperature, and increases at a temperature higher than that. Keep as it is. As described above, in the present embodiment, the change characteristic of the amount of light passing through the light beam limiting unit 12 after reflecting off the reflecting unit 9 (that is, the amount of light at the position on the CCD 20 conjugate with the reflecting unit 9) is monotonous. The characteristic has a changing region (in this embodiment, a monotonically increasing region), a zero-invariable invariable region and a maximum invariant invariant region that are respectively continuous with the monotonic changing region.

According to the present embodiment, the light beam 41 of the reading light emitted from the LD 10 enters the first lens system 11 and becomes a substantially parallel light beam 42. Next, the substantially collimated light beam 42 enters the reflection units 9 of all the pixels of the conversion device 100 at an angle with respect to the normal line of the substrate 1.

On the other hand, the infrared rays from the heat source (target object) 31 are collected by the imaging lens 30 and
An infrared image of the heat source 31 is formed on the surface on which the film 7 as the infrared absorbing portion is distributed. Thereby, infrared rays from the heat source 31 enter the film 7 of the supported part 3 of each pixel of the conversion device 100. This incident infrared ray is absorbed by the film 7 and converted into heat. In response to the heat generated in the film 7, the films 4 and 5 constituting the cantilever are displaced downward and tilt. For this reason, each of the reflecting portions 9 is inclined with respect to the surface of the substrate 1 by an amount corresponding to the amount of infrared light that has entered the infrared absorbing portion 7 corresponding to the reflecting portion 9 from the heat source 31.

The light beam 4 incident on the reflecting portions 9 of all the pixels
2 is a light beam 43 (a set of individual light beams reflected by the individual reflecting portions 9) reflected by these reflecting portions 9;
This time, the light is again incident on the first lens system 11 from the side opposite to the side of the LD 10 and becomes a condensed light flux 44.
Is converged on the light beam restricting unit 12 disposed at the position of the light condensing point. At this time, each individual light beam from the reflection unit 9 of each pixel forms a spot on the light beam restriction unit 12 at a position corresponding to the inclination of the reflection unit 9. Therefore, each individual light beam from the reflection unit 9 of each pixel is adjusted to the amount of light according to the inclination of the reflection unit 9 (that is, according to the amount of infrared light incident on the infrared absorption unit 7 of the pixel from the heat source 31). Then, the light passes through the opening 12 a of the light beam restricting unit 12 and becomes a divergent light beam 45 as a whole, and the second lens system 13
Incident on. Divergent light beam 45 incident on the second lens system 13
Are incident on the light receiving surface of the CCD 20 as a substantially parallel light flux 46 by the second lens system 13, for example. Here, since the plurality of reflecting portions 9 and the light receiving surface of the CCD 20 are conjugated by the lens systems 11 and 13, an image of each reflecting portion 9 is formed on each corresponding portion on the light receiving surface of the CCD 20,
As a whole, an optical image which is a distribution image of the plurality of reflection portions 9 is formed.

As described above, the amount of light of the image of the reflection portion 9 of the pixel in the entire optical image formed on the CCD 20 depends on the amount of infrared rays incident from the heat source 31 to the infrared absorption portion 7 of the pixel. CCD2
The optical image formed by the readout light formed on the light receiving surface 0 is
This reflects the infrared image incident on the converter 100 from the heat source 31. This optical image is captured by the CCD 20. Note that the optical image may be observed with the naked eye using an eyepiece or the like without using the CCD 20 (the same applies to each embodiment described later).

In the present embodiment, as described above, since the shape of the opening 12a of the light beam restricting portion 12 is as shown in FIG. 3, the amount of light passing through the light beam restricting portion 12 is shown in FIG. It has the characteristics shown. Therefore, the positional relationship between the opening 12a and the spot is adjusted and set so that the temperature range of the heat source 31 to be observed is, for example, a range a in FIG. For example, when observing an object having a temperature near normal temperature, the temperature range near normal temperature is set to be the range of FIG. In this case, in the observation temperature range near room temperature, the higher the temperature of the target object, the higher the amount of light passing through the opening 12a, and the higher the amount of light of the image of the corresponding reflection unit 9 on the CCD 20. Therefore, since the temperature of the sun or the like is high, even if an object having a temperature near room temperature is to be observed, the amount of light passing through the opening 12a is originally high when infrared rays from the object such as the sun are incident. , The light quantity of the image of the corresponding reflection section 9 on the CCD 20 should be high. The temperature of the sun and the like is very high as shown by c in FIG. 4, but in the present embodiment,
Since the characteristics shown in FIG. 4 are obtained, the opening 12
The amount of light passing through “a” increases, and the amount of light of the image of the corresponding reflection unit 9 on the CCD 20 increases. Therefore, according to the present embodiment, a natural image can be obtained.

This embodiment may be modified as follows. That is, the opening 12a and the light shielding region 12b in FIG. 3 may be exchanged. In this case, for example, a transparent plate having a light shielding film formed in a region corresponding to the opening 12a in FIG. In this case, C
The light / dark state of the optical image formed on the CD 20 is reversed.

Further, in the present embodiment, for example, instead of the light beam limiting unit 12 shown in FIG. 3, the light beam limiting unit 12 shown in FIGS. 5, 6 and 7 may be used. In the light beam restricting unit 12 shown in FIG. 5, the opening 12a is formed in a trumpet shape. In the light flux limiting unit 12 shown in FIG.
A light-transmitting region 1 is defined by a boundary line 12c having a semicircular portion having a diameter slightly larger than the diameter of the spot S0 extending mainly in the Y direction.
2a and the light shielding area 12b are divided. The light beam limiting unit 12 shown in FIGS. 5 and 6 can obtain the same characteristics as those shown in FIG. Ray bundle limiting unit 1 shown in FIG.
In FIG. 2, the light-transmitting region 12a and the light-shielding region 12b are separated by a straight boundary line 12c extending in the Y direction. FIG.
The same characteristics as the characteristics shown in FIG. 4 can also be obtained by the light beam limiting unit 12 shown in FIG. In the case of FIGS. 6 and 7, for example, a transparent plate in which a light-shielding film is formed in a region corresponding to the light-shielding region 12 b may be used.
A light-shielding plate having only the light-shielding region 12b having the boundary 12c as an edge may be used. In FIGS. 5, 6, and 7, it goes without saying that the light-transmitting region (including the opening) 12a and the light-shielding region 12b may be interchanged.

[Second Embodiment]

FIG. 8 is a schematic configuration diagram showing an imaging device according to the second embodiment of the present invention. 8, elements that are the same as elements in FIG. 1 or that correspond to elements in FIG. 1 are given the same reference numerals, and overlapping descriptions are omitted.

This embodiment is different from the first embodiment in that the reading light supply section is constituted by a xenon lamp 60, a condenser lens 61, a reflection mirror 62 and an illumination light stop 63 instead of the LD 10. Only points. The illumination light stop 63 has a light-shielding plate constituting the light beam restriction unit 12 extending therethrough. The LD 10 in FIG.
Is provided by providing an opening 63a at a position corresponding to the readout light emission position of the above. However, the illumination light stop 63 may be configured to be independent of the light beam restriction unit 12.

The light beam 4 emitted from the xenon lamp 60
7 is condensed by the condenser lens 61 and reflected by the reflection mirror 62, and then condensed on the opening 63a. The divergent light beam 41 emitted from the opening 63a is transmitted to the first lens system 11
And is made substantially parallel. The subsequent operation is the same as in the first embodiment.

According to this embodiment, the same advantages as those of the first embodiment can be obtained. The illumination light stop 63 is not necessarily provided, but it is preferable to provide the illumination light stop 63 in order to increase the contrast of the optical image on the CCD 20. In the first embodiment, the LD
A readout light stop may be provided at the front of 10.

[Third Embodiment]

FIG. 9 is a schematic configuration diagram showing an imaging device according to the third embodiment of the present invention. In FIG. 9, the same or corresponding elements as those in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

The present embodiment is different from the first embodiment in that a light beam limiting unit 70 which uses reflected light as a transmitting light instead of the light beam limiting unit 12 which uses transmitted light as a transmitted light is used. ,
The only difference is that the arrangement of the second lens system 13 and the CCD 20 is changed accordingly.

The light beam restricting section 70 is provided with the aperture 12a shown in FIG.
And the light-shielding region 1 in FIG.
2b.
The light flux restricting unit 70 can be formed of, for example, a transparent plate having a reflective film formed in a region corresponding to the reflective region 70a. In the present embodiment, the area of the reflection area 70a of the light beam restricting unit 70 is a part that selectively passes (reflects in the present embodiment) only the desired light beam, and the second lens system Reference numeral 13 guides the light beam reflected by the reflection area 70a to the conjugate position.

According to this embodiment, advantages similar to those of the first embodiment can be obtained.

In this embodiment, instead of the light beam restricting portion 70, the light beam restricting portions 12 shown in FIGS. 5, 6 and 7 are replaced by a light transmitting region 12a serving as a reflecting region and a light shielding region. What deform | transformed so that 12b may become a translucent area | region may be used. It goes without saying that in the present embodiment and the above-described modifications, the translucent region and the reflective region may be interchanged.

[Fourth Embodiment]

FIG. 10 shows the state of spots S1 and S2 formed by light reflected by the two reflecting portions 9 on the light beam restricting portion 12 in the imaging device according to the fourth embodiment of the present invention. FIG. 10, elements that are the same as or correspond to the elements in FIG. 3 are given the same reference numerals, and duplicate descriptions thereof will be omitted.

This embodiment is different from the above-described first embodiment shown in FIGS. 1 to 3 in that the shape of the opening 12a of the light beam restricting portion 12 is a wedge shape as shown in FIG. It is only a point.

In this embodiment as well as in each of the embodiments described above, the conversion device 100 is ideally manufactured, and no infrared light from the target object is incident on the infrared absorbing portions 7 of any of the pixels. In the initial state, if the surfaces of the reflecting portions 9 of all the pixels are parallel to the surface of the substrate 1, the individual light beams from the reflecting portions 9 of all the pixels are completely To form the same spot.

However, when the conversion device 100 is actually manufactured, the angle of the surface of the reflection portion 9 varies for each pixel in an initial state in which no infrared light from the target object is incident on any pixel. , As shown in FIG.
The positions of the spots formed by the individual light beams from each pixel vary. FIG. 10 shows a spot S1 formed most on the −X direction side and a spot S2 formed most on the + X direction side. Thus, the spot is mainly X
The variation in the direction is due to the structure of the pixel shown in FIG. The distance L1 in the X direction from the spot S1 to the spot S2 is an initial variation of a plurality of spots formed on the light flux limiting unit 12 by the readout light reflected by the reflecting units 9 of all the pixels. , The distribution width in the X direction (the moving direction of the spot). From this state, when the same amount (maximum allowable amount) of infrared rays is incident on all the pixels from the target object, the spots S1, S
2 move in the X direction, respectively, and spots S1 'and S2'
Becomes

As shown in FIG. 10, in the shape of the wedge-shaped opening 12a of the light beam restricting portion 12, as the spot is located on the −X direction side within the range of the distance L2, the overlapping area with the spot becomes smaller. (In other words, such that the closer the spot is to the + X direction side, the larger the overlapping area with the spot becomes). In the present embodiment, the distance L2 is set to be the same as the distance from the position of the spot S1 to the position of the spot S2 '.

In this embodiment, since the shape of the opening 12a of the light beam restricting section 12 is set as described above, the spot and the opening 12a are located within the temperature range to be observed.
Is set as shown in FIG. 10, even if the spots vary greatly as spots S1 and S2, they can be moved between spots S1 'and S2' respectively. , The passing light amount changes.
Therefore, according to the present embodiment, even though the amount of incident infrared light from the target object with respect to the pixel changes, the light amount of the image corresponding to the pixel in the optical image formed by the reading light does not change at all. However, the same situation as a pixel defect does not occur. Therefore, the image quality of the obtained image can be significantly improved.

By the way, if the distance L2 is set to be equal to or longer than the distance from the position of the spot S1 to the position of the spot S2 'as in the present embodiment, all the dispersed spots are changed before and after the movement. Since the amount of transmitted light changes, the same situation as a pixel defect does not occur for all pixels, which is very preferable. However, in the present invention, the distance L2 may be equal to or longer than the distribution width L1. Even if the distance L2 is the same as the distribution width L1, as can be seen from FIG. 10, the passing light amount changes before and after movement of many spots, and the same situation as a pixel defect does not occur for many pixels.
The image quality is remarkably improved as compared with the related art described with reference to FIG.

In the present embodiment, for example, instead of the light beam restricting unit 12 shown in FIG. 10, a light beam restricting unit 12 shown in FIGS. 11, 12 and 13 may be used.

In the ray bundle restricting section 12 shown in FIG. 10, the oblique sides on both sides of the wedge-shaped opening 12a are straight,
1, the oblique sides on both sides of the opening 12a are curved. When the oblique side is formed by a straight line as in the case of FIG. 10, the light intensity distribution of the spot is not uniform, and the intensity increases toward the center. The amount of light passing through 12 (therefore, the amount of light on the CCD 20) does not change linearly. If the oblique side of the opening 12a is formed as a curve as shown in FIG. 11, it is also possible to linearly change the amount of light passing through the light flux limiting unit 12 with respect to a change in the amount of incident infrared rays from the target object.

The aperture 12 of the light beam restricting section 12 shown in FIG.
a has both the features of the opening 12a of the light beam limiting unit 12 shown in FIG. 10 and the features of the opening 12a of the light beam limiting unit 12 shown in FIG. That is, the opening 12a of the light beam restricting unit 12 shown in FIG. 12 has a shape combining a wedge-shaped portion and an elongated portion extending in the X direction, which is slightly wider than the spot diameter in the Y direction. Therefore, by using the light flux limiting unit 12 shown in FIG. 12, both the advantage of the first embodiment (obtaining natural pixels) and the advantage of the fourth embodiment (improvement of image quality) are obtained. Obtainable.

The light transmitting area 12a of the light beam restricting section 12 shown in FIG.
And the light transmitting area 12a of the light beam restricting unit 12 shown in FIG.
It has the features of Therefore, even if the light beam restricting unit 12 shown in FIG. 13 is used, both the advantage of the first embodiment (obtaining natural pixels) and the advantage of the fourth embodiment (improvement of image quality) are obtained. Can also be obtained.

In the light beam limiting section 12 shown in each of FIGS. 10 to 13, the light transmitting area (including the aperture) 12
It is needless to say that a and the light-shielding region 12b may be interchanged. If the optical system is configured in the same manner as in FIG.
In the light beam restricting unit 12 shown in FIGS. 10 to 13 and the modifications thereof, the light transmitting region 12a may be modified to be a reflection region and the light shielding region 12b may be modified to be a light transmitting region.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

[0069]

As described above, according to the present invention,
Natural images can be obtained.

Further, according to the present invention, even if the characteristics of the displacement portion vary, it is possible to reduce the rate of occurrence of pixels that cause the same situation as a pixel defect, and to improve the quality of the obtained image. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an imaging device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an optical readout type radiation-to-displacement conversion device used in the first embodiment of the present invention.

FIG. 3 is a diagram showing a light beam restricting portion used in the first embodiment of the present invention and a state of a spot formed thereon.

FIG. 4 is a characteristic diagram illustrating a relationship between the temperature of the target object and the amount of light passing through the light flux limiting unit according to the first embodiment of the present invention.

FIG. 5 is a view showing a state of a light beam restricting portion according to a modification of the light beam restricting portion shown in FIG. 3 and spots formed thereon.

FIG. 6 is a diagram showing a state of a light beam restricting unit according to another modification of the light beam restricting unit shown in FIG. 3 and spots formed thereon.

FIG. 7 is a diagram showing a light beam restricting portion according to still another modification of the light beam restricting portion shown in FIG. 3 and a state of a spot formed thereon.

FIG. 8 is a schematic configuration diagram illustrating an imaging device according to a second embodiment of the present invention.

FIG. 9 is a schematic configuration diagram showing an imaging device according to a third embodiment of the present invention.

FIG. 10 is a diagram showing a state of a light beam restricting unit used in an imaging device according to a fourth embodiment of the present invention and a spot formed thereon.

FIG. 11 is a diagram illustrating a state of a light beam restricting unit according to a modification of the light beam restricting unit illustrated in FIG. 10 and spots formed thereon.

FIG. 12 is a diagram showing a light beam restricting unit according to another modification of the light beam restricting unit shown in FIG. 10 and a state of a spot formed thereon.

FIG. 13 is a diagram showing a light beam restricting unit according to still another modification of the light beam restricting unit shown in FIG. 10 and a state of a spot formed thereon.

FIG. 14 is a diagram showing a light beam restricting portion used in a conventional imaging device and a state of a spot formed thereon.

FIG. 15 is a characteristic diagram showing a relationship between the temperature of a target object and the amount of light passing through a light flux limiting unit in a conventional imaging device.

FIG. 16 is a diagram showing another state of a light beam restricting portion used in a conventional imaging device and a spot formed thereon.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 9 Reflecting part 10 LD (laser diode) 11 1st lens system 12 Ray bundle limiting part 12a Opening (or translucent area) 12b Shielding area 13 2nd lens system 20 CCD 30 Imaging lens 31 Heat source (target object) 34 First lens system 100 Optical readout radiation-displacement converter

Continued on front page F-term (reference) 2G065 AA04 AA11 AB02 AB05 BA04 BA34 BB06 BB11 BB46 DA18 DA20 2G066 BA14 BA20 BA22 BA25 CA02 CA08

Claims (4)

[Claims] 1. An imaging device for converting radiation arriving within a predetermined range into an optical image, wherein the radiation is arranged at a plurality of positions within the predetermined range, and the radiation received at the plurality of positions is converted into heat. A plurality of radiation absorbing portions to be converted, a plurality of displacement portions each of which converts each heat converted by the plurality of radiation absorption portions into displacements at positions corresponding to the plurality of portions, and according to displacements of the plurality of displacement portions. A light-reading radiation-displacement converter including a plurality of reflectors each having a change in inclination; a reading light supply unit for supplying reading light; and a plurality of the light-reading radiation-displacement converters for reading the reading light. A first lens system for guiding the light beam to the reflecting portion, and a light beam for selectively passing only a desired light beam among the light beams of the readout light reflected by the plurality of reflecting portions after passing through the first lens system. A restricting unit; A second lens system that forms a conjugate position with the plurality of reflecting portions in cooperation with the lens system and guides the light beam that has passed through the light beam limiting portion to the conjugate position. The reading light supply unit supplies the reading light so that the reading light passes through a region on one side with respect to an optical axis of the first lens system, and the light beam limiting unit includes the desired light beam. The passage portion for selectively passing only the bundle is arranged in a region on the other side with respect to the optical axis of the first lens system. An imaging apparatus characterized in that a change in the amount of light at a position conjugate with the reflection section with respect to a change in the inclination of the section is set so as not to reverse. 2. A shape of the passing portion of the light beam restricting portion is such that a change characteristic of a light amount at a position conjugate with the reflecting portion with respect to a change in inclination of each of the reflecting portions is a monotone changing region and a monotonic changing region. 2. The imaging apparatus according to claim 1, wherein the characteristic is set so as to have an invariable area continuous with the image. 3. The shape of the light passing portion of the light beam restricting portion is such that each spot formed on the light beam restricting portion by the readout light reflected by each of the reflecting portions has an inclination of each of the reflecting portions. Within a range of a predetermined distance along the moving direction in which the spot moves in accordance with the change, the overlapping area or the non-overlapping area with the spot becomes smaller or larger as the spot is located on one side of the moving direction. The predetermined distance is a distribution in the movement direction of the plurality of spots respectively formed on the light flux limiting unit by the readout light reflected by the plurality of reflection units, due to an initial variation. 3. The imaging device according to claim 1, wherein the width is equal to or longer than the width. 4. An imaging device for converting radiation arriving within a predetermined range into an optical image, wherein the radiation is arranged at a plurality of positions located within the predetermined range, and the radiation received at the plurality of positions is converted into heat. A plurality of radiation absorbing portions to be converted, a plurality of displacement portions each of which converts each heat converted by the plurality of radiation absorption portions into displacements at positions corresponding to the plurality of portions, and according to displacements of the plurality of displacement portions. A light-reading radiation-displacement converter including a plurality of reflectors each having a change in inclination; a reading light supply unit for supplying reading light; and a plurality of the light-reading radiation-displacement converters for reading the reading light. A first lens system for guiding the light beam to the reflecting portion, and a light beam for selectively passing only a desired light beam among the light beams of the readout light reflected by the plurality of reflecting portions after passing through the first lens system. A restricting unit; A second lens system that forms a conjugate position with the plurality of reflecting portions in cooperation with the lens system and guides the light beam that has passed through the light beam limiting portion to the conjugate position. The reading light supply unit supplies the reading light so that the reading light passes through a region on one side with respect to an optical axis of the first lens system, and the light beam limiting unit includes the desired light beam. The passage portion for selectively passing only the bundle is configured to be arranged in a region on the other side with respect to the optical axis of the first lens system. Within a range of a predetermined distance along a moving direction in which each spot formed on the light beam restricting unit by the readout light reflected by the unit moves in accordance with a change in the inclination of each reflecting unit, the spot is One side of the moving direction The overlapping area or the non-overlapping area with the spot is set to be smaller or larger as the position is located, and the predetermined distance is limited by the light flux by reading light reflected by each of the plurality of reflecting portions. An imaging apparatus characterized in that a plurality of spots respectively formed on a portion have a distribution width equal to or longer than a distribution width in the movement direction due to an initial variation.