JP2002228520A - Calibration light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a calibration light source device capable of emitting stable calibration light without being affected by unnecessary infrared rays varying in emission quantity with changes in ambient temperature, and further to provide a calibration light source device applicable to an observation device for observing a wide wavelength band including not only infrared but also visible light and capable of calibrating wavelengths for an observation device having a spectroscope. SOLUTION: In this calibration light source device 1 for calibrating the sensitivity of an observation device 8, an aperture stop 4 is disposed in parallel light beams and a surface of the aperture stop 4 facing the observation device 8 is adapted to be a reflective surface, thereby preventing unnecessary infrared rays emitted by the source device 1 from coming into a detector 10 of the observation device 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a calibration light source device for optically calibrating an observation device installed at a focal point of a telescope, for example.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view showing a conventional infrared observation apparatus provided with a reference light source for calibration disclosed in Japanese Patent Application Laid-Open No. 2-208526. In the figure, reference numeral 25 denotes an object to be observed; 26, an infrared reference light source for calibration; 28, an infrared optical system; an objective lens 29, a field stop 30 provided at the focal point of the objective lens 29, a relay lens 31, and the above-described components. Is constituted by a lens barrel 32 that supports
33 is an infrared detector constituted by a two-dimensional array element, 3
4 is a storage circuit for storing the output of the infrared detector 33;
Is an arithmetic circuit for calculating the output of the infrared detector 33, and 36 is a signal processing circuit composed of a storage circuit 34 and an arithmetic circuit 35.

Next, the sensitivity calibration operation of the infrared observation apparatus provided with the conventional calibration infrared reference light source 26 shown in FIG. 7 will be described. The relay lens 31 is connected to the objective lens 29
The intermediate image of the infrared reference light source 26 and the image of the field stop 30 formed by the above are formed on the infrared detector 33. At this time, the infrared detector 33 receives unnecessary infrared rays emitted by the infrared optical system 28 in addition to the infrared rays emitted by the infrared reference light source 26. In order to remove the unnecessary amount of infrared rays, first, the output of the infrared ray detector 33 obtained by the infrared ray reference light source 26 having a known temperature is stored in the storage circuit 34 as calibration data. Next, the output value recorded in the storage circuit 34 is subtracted by the arithmetic circuit 35 from the output of the infrared detector 33 obtained by changing the temperature of the infrared reference light source 26, so that the radiation amount due to the temperature difference of the infrared reference light source 26 is obtained. Can be detected.

However, if there is a temperature difference in the infrared optical system 28 when the temperature of the infrared reference light source 26 is changed,
The amount of unnecessary infrared radiation emitted by the infrared optical system 28 differs,
Correct calibration cannot be performed. For this reason, when acquiring calibration data using the infrared reference light source 26, the temperature of the infrared optical system 28 is changed and measurement is performed, and the storage circuit 34 is used as a calibration data group.
Must be stored.

[0005] The relay lens 31 is configured to form an image of the field stop 30 in addition to the infrared reference light source 26 on the infrared detector 33. Of the two-dimensional array elements of the infrared detector 33, the field stop 30 The temperature of the infrared optical system 28 can be estimated from the output signals of some of the elements on which the image of the field stop 30 is formed, and from the calibration data group recorded in the storage circuit 34, the element on which the image of the field stop 30 is formed By selecting the calibration data close to the output value corresponding to the above, it is possible to remove the influence of unnecessary infrared rays in a state close to the temperature of the infrared optical system 28 at the time of observation.

[0006]

Since sensitivity calibration in a conventional infrared observation apparatus having an infrared reference light source 26 for calibration is performed by the above-described method, the infrared optical system 28 is used.
In order to calibrate the influence of unnecessary infrared rays emitted from the infrared optical system 28, a large amount of calibration data must be acquired and stored by changing the temperature of the infrared optical system 28 in advance, and the infrared detector 3
Since the image of the field stop 30 is formed in a part of No. 3, there is a problem that the observation field of view is narrowed.

In order to obtain calibration data in which the amount of light of the infrared reference light source 26 required for calibrating the linearity of the output of the infrared detector 33 has to be changed, the temperature of the infrared reference light source 26 must be changed. When the temperature of the infrared reference light source 26 is changed, not only the light amount of the calibration light but also its spectral characteristics change. Therefore, in the case of an observation device that performs spectroscopy, it is necessary to correct the change in the spectral characteristics of the calibration light, and the processing is complicated. There was a problem of becoming. Furthermore, since the infrared reference light source 26 is limited to calibration light having a continuous spectrum, there is a problem that wavelength calibration cannot be performed in an observation device that performs spectroscopic measurement. Furthermore, in order to acquire the calibration data, the opening of the infrared optical system 28 is
In the case of an observation device having a large-diameter infrared optical system 28, there is a problem that the infrared reference light source 26 becomes large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises a reference light source and an infrared optical system. Calibration that can emit stable calibration light without receiving it, can be applied to observation equipment that observes a wide wavelength range including not only infrared light but also visible light, and can also perform wavelength calibration of observation equipment that has a spectrometer. It is intended to obtain a light source device for use.

[0009]

According to the present invention, there is provided a calibration light source device for optically calibrating an observation device according to the present invention, comprising: a light source; a condenser lens for converting the calibration light emitted from the light source into parallel light; An illumination lens for irradiating the focal plane, and an aperture stop arranged in a parallel light beam between the condenser lens and the illumination lens are provided, and the surface of the aperture stop on the observation device side is an infrared reflection surface. Further, in a calibration light source device for optically calibrating an observation device, a light source, a condensing lens for collimating calibration light emitted from the light source, an irradiation lens for irradiating the observation device focal plane with the calibration light, and a condensing lens. An aperture stop arranged in a parallel light beam between the lens and the irradiation lens, and a multilayer filter that provides low reflection in the visible region and high reflection in the infrared region is provided on the surface of the aperture stop on the observation device side. It is.

Also, a reflection type density filter is arranged near the aperture stop. In addition, the size of the aperture stop is matched with the exit pupil of the main optical system of the observation device. In addition, a sub-mirror of an observation device having a reflection type main optical system and a shielding plate corresponding to a supporting mechanism are installed in the aperture stop, and the temperature of the aperture stop is set based on a temperature sensor attached to the sub-mirror. It is intended to be controlled. In addition, a continuous spectrum lamp and a bright line lamp are arranged inside using an integrating sphere as a light source, and are switched on and turned on. Further, a plurality of light sources are provided, and the light sources can be switched by a light source switching mechanism.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 A calibration light source device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram for explaining a calibration light source device according to Embodiment 1 of the present invention. In the figure, reference numeral 1 denotes a light source device for calibration, which comprises a light source 2 composed of, for example, an integrating sphere, a condenser lens 3, an aperture stop 4, and an irradiation lens 5. Reference numeral 6 denotes calibration light, 7 denotes a focal plane of the observation device 8, 9 denotes an observation optical system of the observation device 8, 10 denotes a detector of the observation device 8, and 11 denotes a cold shield for cooling the detector 10. In addition,
The surface of the aperture stop 4 on the observation device 8 side is an infrared reflection surface.

Next, the operation will be described. The calibration light 6 emitted from the light source 2 of the calibration light source device 1 is collimated by the condenser lens 3, the luminous flux diameter is limited by the aperture stop 4, and then condensed by the irradiation lens 5 to be focused on the focal plane 7. 2 is magnified, and the image on the focal plane 7 is received by the observation device 8 which forms the image on the detector 10. When the observation device 8 is an infrared observation device, the detector 10 is generally cooled, and the detector 10 is used to prevent the incidence of unnecessary infrared rays radiated from the surroundings.
Is covered with a cooled cold shield 11, but unnecessary infrared rays emitted by the aperture stop 4 from the opening of the cold shield 11 are incident by diffraction or the like. In order to prevent this, the surface of the aperture stop 4 on the observation device 8 side is an infrared reflecting surface, and when viewed from the detector 10, passes through the edge of the opening of the cold shield 11 as shown by a broken line in FIG. The reflected light is reflected by the infrared reflecting surface of the aperture stop 4 and returns to the cooled detector 10 again.

According to this embodiment, by making the surface of the aperture stop 4 on the observation device 8 side a reflecting surface, unnecessary infrared rays radiated from the aperture stop 4 incident from the opening of the cold shield 11 can be detected. When viewed from the detector 10, the light passing through the edge of the opening of the cold shield 11 is reflected by the infrared reflecting surface of the aperture stop 4 and returns to the cooled detector 10 again. Through the periphery of the opening, the user can see himself / herself cooled down, and can obtain stable calibration light 6 which is not affected by unnecessary infrared rays emitted from the aperture stop 4 which changes depending on the temperature environment of the calibration light source device 1. .

Embodiment 2 FIG. In the first embodiment, the case where the observation device 8 is an infrared observation device is described. However, when the observation device 8 is not an infrared observation device, the light reflected by the detector 10 is reflected by the aperture stop 4. , Again the detector 10
Aperture stop 4 to prevent stray light from entering the aperture stop.
The surface of the observation device 8 is provided with a multilayer filter having low reflection in the visible region and high reflection in the infrared region, and the light reflected by the detector 10 is reflected by the aperture stop 4, and is reflected again by the detector 10. Prevent from entering.

According to the present embodiment, by providing a multilayer filter having low reflection in the visible region and high reflection in the infrared region on the surface of the aperture stop 4 on the observation device 8 side, the visible region other than the infrared region is also provided. It is possible to obtain a calibration light source device that can be applied to an observation device that observes a wavelength range including the above. In addition,
FIG. 2 is a diagram illustrating an example of the spectral reflectance characteristics of the multilayer filter.

Embodiment 3 FIG. 3 is a configuration diagram for explaining a calibration light source device according to Embodiment 3 of the present invention. In the figure, reference numeral 12 denotes a reflection type density filter arranged near the aperture stop 4. The other configuration is the same as that of the first embodiment, and the description is omitted.

In this embodiment, the calibration light 6 is provided by disposing the reflection type density filter 12 near the aperture stop 4.
Can be adjusted by switching the brightness of the observation device 8, and the linearity of the observation device 8 can be easily calibrated. Since the detector 10 looks at itself by the reflection of the reflection type density filter 12, it is possible to obtain the stable calibration light 6 which is not affected by the unnecessary infrared rays emitted from the reflection type density filter 12.

Embodiment 4 FIG. 4 is a configuration diagram for explaining a calibration light source device according to a fourth embodiment of the present invention.
A case where the observation device 8 has a large-diameter main optical system 13 is shown. In the drawing, reference numeral 13 denotes a large-diameter main optical system, 1
Reference numeral 4 denotes a main optical system exit pupil. Note that the configuration of the calibration light source device is the same as in each of the above embodiments, and a description thereof will be omitted.

In this embodiment, the calibration light source device 1 is inserted in the vicinity of the focal plane 7, the size of the aperture stop 4 of the calibration light source device 1 is matched with the size of the exit pupil 14 of the main optical system, and the observation device The F ratio of the main optical system 13 and the F ratio of the calibration light of the calibration light source device 1 are made the same. According to the present embodiment, the size of the aperture stop 4 of the calibration light source device 1 is adjusted by changing the size of the main optical system exit pupil 14.
The calibration light source device 1 can be reduced in size as compared with the main optical system 13 and calibration can be performed under the same conditions as during observation.

Embodiment 5 FIG. 5 is a diagram for explaining a calibration light source device according to a fifth embodiment of the present invention.
(A) is a block diagram, (b) is an enlarged plan view of an aperture stop. In the present embodiment, the case where the main optical system 13 of the observation device 8 is a reflection optical system is shown. In the figure, 15 is a primary mirror, 16 is a secondary mirror, 17 is a spider that supports the secondary mirror 16,
Reference numeral 18 denotes a temperature sensor attached to the sub-mirror 16, 19 denotes a driving mechanism of the light source device 1 for calibration, 20 denotes an aperture stop on which a shielding plate simulating the shadow of the sub-mirror 16 and the spider 17 is mounted, and 21a denotes an aperture stop. Reference numeral 21b denotes a temperature control device attached to the aperture stop 20, and reference numeral 21b denotes a temperature sensor attached to the aperture stop 20. Note that other configurations are the same as those of the above-described embodiments, and a description thereof will not be repeated.

In the present embodiment, the secondary mirror 16 of the observation device 8
Based on the temperature detected by the temperature sensor 18 attached to
The temperature of the aperture stop 20 having the shielding plate is measured by a temperature sensor 21b.
Further, the calibration can be performed under the same conditions as those at the time of observation by controlling with the temperature control device 21a constituted by, for example, a Peltier element.

In each of the above embodiments, a lamp emitting a continuous spectrum is assumed as the light source 2.
In the case where an integrating sphere is used, an emission line lamp having a specific emission line is arranged in addition to the continuous spectrum lamp, and the wavelength is calibrated by switching and lighting the observation device having the spectroscopic device.

Embodiment 6 FIG. FIG. 6 is a configuration diagram for explaining a calibration light source device according to the sixth embodiment, and shows a case where a plurality of light sources are provided. In the figure, 22 is a bright line light source, 23 is a light source switching mechanism in the calibration light source device 1, and 24 is a folding mirror provided in the light source switching mechanism 23. Other configurations are the same as those of the above-described embodiments, and the description is omitted.

In the present embodiment, the light source switching mechanism 2
3 is driven, and the light source device 1 for calibration is
Is switched from the light source 2 to the bright line light source 22 to perform wavelength calibration. According to the present embodiment, by switching the light source, the wavelength configuration of the observation device having the spectroscopic device can be performed, and a wavelength that is brighter than when the bright line lamp is arranged in the integrating sphere used for the light source 2. Calibration light is obtained.

[0025]

As described above, according to the present invention, a calibration light source is provided by arranging an aperture stop whose surface on the observation device side is an infrared reflecting surface in a parallel light beam formed by a condenser lens. It is possible to obtain a calibration light source device that can emit stable calibration light with little influence of unnecessary infrared rays emitted from the device.In addition, the surface of the aperture stop on the observation device side has low reflection in the visible region and high reflection in the infrared region. By providing a multilayer filter, a light source device for calibration with less stray light to the visible observation device can be obtained.

Further, by arranging the reflection type density filter near the aperture stop, it is possible to easily adjust the light amount of the calibration light which is less affected by unnecessary infrared rays. When the observation device has a large-diameter main optical system, the size of the aperture stop is matched with the size of the exit pupil of the observation device main optical system, so that a small calibration light source device can be used for observation. Calibration can be performed under the same conditions as described above. Furthermore, when the main optical system of the observation device is a reflection optical system, a shield plate corresponding to the sub-mirror of the observation device and its support mechanism is attached to the aperture stop, and the temperature is the same as that of the sub-mirror of the main optical system. By controlling so as to obtain a calibration light source device that can emit calibration light under the same conditions as during observation, it is possible to obtain a calibration light source device. In addition, by arranging an emission line lamp in addition to a continuous spectrum lamp as a light source and switching the lighting or selecting a light source by a driving mechanism for switching the light source, performing wavelength calibration of an observation device having a spectroscopic device. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram showing a calibration light source device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a spectral reflectance characteristic of an aperture stop according to a second embodiment of the present invention;

FIG. 3 is a diagram showing a calibration light source device according to Embodiment 3 of the present invention.

FIG. 4 is a diagram showing a calibration light source device according to Embodiment 4 of the present invention.

FIG. 5 is a diagram showing a calibration light source device according to a fifth embodiment of the present invention.

FIG. 6 is a diagram showing a calibration light source device according to Embodiment 6 of the present invention.

FIG. 7 is a diagram showing a conventional observation apparatus provided with a reference light source for this type of calibration.

[Explanation of symbols]

1 is a light source device for calibration, 2 light sources, 3 condenser lenses, 4
Aperture stop, 5 Irradiation lens 5, 6 Calibration light, 7 Focal plane, 8 Observation device, 9 Observation optical system, 10 Detector, 1
1 cold shield, 12 reflection density filter, 1
3 Large diameter main optical system, 14 Main optical system exit pupil, 15
Primary mirror, 16 secondary mirror, 17 spider, 18 temperature sensor, 19 drive mechanism, 20 aperture stop, 21a temperature controller, 21b temperature sensor, 22 bright line light source, 23
Light source switching mechanism, 24 folding mirror.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02B 17/08 G02B 17/08 Z

Claims (7)

[Claims] 1. A calibration light source device for optically calibrating an observation device, comprising: a light source; a condenser lens for collimating calibration light emitted from the light source; and irradiating the observation device focal plane with the calibration light. An illumination lens, and an aperture stop arranged in a parallel light beam between the condenser lens and the illumination lens, wherein the surface of the aperture stop on the observation device side is an infrared reflection surface. Light source device for calibration. 2. A calibration light source device for optically calibrating an observation device, comprising: a light source; a condenser lens for collimating calibration light emitted from the light source; and irradiating the observation device focal plane with the calibration light. An illumination lens, comprising: an aperture stop arranged in a parallel light flux between the condenser lens and the illumination lens; low reflection in the visible range on a surface of the aperture stop on the observation device side;
A calibration light source device comprising a multilayer filter that exhibits high reflection in the infrared region. 3. The calibration light source device according to claim 1, wherein a reflection type density filter is arranged near the aperture stop. 4. The calibration light source device according to claim 1, wherein the size of the aperture stop and the exit pupil of the main optical system of the observation device are matched. 5. A sub-mirror of an observation device having a reflection-type main optical system and a shielding plate corresponding to a support mechanism thereof are attached to an aperture stop, and the aperture is set based on a value indicated by a temperature sensor attached to the sub-mirror. The calibration light source device according to any one of claims 1 to 4, wherein the temperature of the aperture is controlled. 6. A lamp according to claim 1, wherein a continuous spectrum lamp and a bright line lamp are disposed inside using an integrating sphere as a light source, and said lamps are switched and lit.
The light source device for calibration according to any one of claims 1 to 7. 7. The calibration light source device according to claim 1, wherein a plurality of light sources are provided, and said light sources can be switched by a light source switching mechanism.