JPH0466486B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF INDUSTRIAL APPLICATION This invention relates to scanning and detection systems for radiation, such as infrared radiation. [Prior Art and its Problems] Various forms of radiation scanning and detection systems are already well known, but they are designed to receive collimated light from far-field scenes, and the compactness of the systems had also reached its limit. It is an object of the present invention to provide a new and improved compact radiation scanning and detection system. [Means for solving the problems] The present invention provides a radiation scanning system having the following configuration.
A detection system is provided. That is, an optical system that receives scanning radiation, has an accessible exit pupil, and forms an external real image of the received radiation; and radiation emitted by the optical system. a scanning system for scanning a line, comprising: an optical conjugate imaging means of the exit pupil; a first scanning device located in the exit pupil;
a second scanning device located in the conjugate pupil, and the first and second scanning devices are arranged in mutually orthogonal scanning directions; a detection system for detecting radiation emitted by the scanning system; , a detection system comprising optical conjugate imaging means for the real image and a radiation detector located at the conjugate real image; It is characterized in that it constitutes a substantially spherical concave mirror located approximately concentrically with the detector real image locus that is imaged by the device. Since the system according to the present invention does not require positioning the real image locus of the detector on the focal surface of the concave mirror as in conventional systems, the angular area of the concave mirror can be substantially omitted and the related system can be extremely miniaturized. Ru. This is because the radiation-receiving optical system becomes a focal point and forms a real image of a distant scene that is easily incident. Preferably, the first scanning device is configured such that a plane flap mirror oscillates at a relatively slow speed for frame scanning, while the second scanning device is preferably configured such that a rotor rotates at a relatively high speed for line scanning. The rotor is generally substantially perpendicular to the rotor's axis of rotation and has a planar reflective facet integrated around the rotor. The conjugate real image imaging means is constituted by a simple transfer lens, in which case the second scanning device is placed intermediate the lens and the detected real image formed thereby. Furthermore, the conjugate real image imaging means may be constituted by a transfer lens, a radiation switching rotor substantially installed on the detection real image formed by the transfer lens, and a real image relay device in the form of a concave mirror for convenience; in this case, A second scanning device is installed between the real image relay device and the relay real image formed thereon. Such conjugate real image imaging means are described in British Patent No. 2115174, which is incorporated as prior art to the present invention. The real image of the detection locus imaged by the conjugate pupil forming means preferably has a curved surface centered on the exit pupil. The reason for this is that the scanning locus imaged by the first scanning device is also centered on the exit pupil, so that the axisymmetric optical system can utilize an external real image with a field curve centered on said exit pupil. If the loci have different curved surfaces, preferably the external real image of the optical system has a visual field curved surface that meets the compromise value. Embodiments of the present invention will be described as examples based on the drawings. [Example] As shown in FIG. 1, a system 10 of the present invention includes an optical system 11. This optical system 11 receives radiation (for example, infrared radiation) from an objective space 12,
The optical system 11 consists of a refractive optical element for forming a real image 13 into which the received radiation is likely to enter into the image space of the optical system, and this optical system 11 has an exit pupil 14 through which the radiation passes before the arriving real image 13. Equipped with. Further, the optical system 11 is formed of lens elements A, B, C, and D arranged on a common optical axis 9, and the locus of the radiation ray passing through this optical system 11 is represented by a selected radiation ray bundle. The radiation that crosses the optical system 11 is transmitted through the radiation scanning system 16.
The radiation scanning system includes a first oscillating flap mirror located in the exit pupil 14.
a scanning device 17 and a second scanning device 18 in the form of a polyhedral rotor, formed by a substantially spherical concave mirror 20 located in the pupil 19 conjugate to the exit pupil 14 and forming part of the scanning system 16, and located in the configuration described above. It consists of After the scanning system 16, the real image 13 is placed on the station 24.
A device 23 and a station 24 for imaging the optical conjugate of
Radiation is collected by a detection system 22 including a radiation detector 25 located at. When the detector 25 is used as a radiation source, the detected real image formed by the device 23 is moved to a normal circular locus by the scanning device 18, and the concave mirror 20
The conjugate pupil of the form is located almost centrally at the real image locus. Due to the focal nature of the optical system 11, the concave mirror 20
can be located close to or at the real image locus, and the angular region of mirror 20 can be omitted, resulting in a compact system 10. A real image 13, which in this example is similar to the detection locus, is located on the surface of the concave mirror 20. System 10 for actual use
The radiation passing through is refracted by refracting mirrors 28, 29, and 30. The scanning device 18 is located in its own housing with gas bearings and a window 31 through which radiation passes. The detector 25 is itself located within a cryogenically cooled housing 32. The embodiment of FIG. 2 differs from optical system 11 of FIG. 1 only in optical system 40, which reduces the axial distance of system 10. The optical system 40 includes an objective lens element,
Mirror G, a mirror surface H formed on a part of the element F
and lens elements i, J, K, and L. In each of the embodiments shown in FIGS. 1 and 2, the device 23 for imaging the optical conjugate of the real image 13 is of the form of a simple transfer lens, and in the arrangement shown in FIG.
3 comprises components of the type described in British Patent No. 2115174. In this way, in FIG. 3, the transfer lens 44 is the polyhedral radiation switching rotor 4.
Station 45 where you pass by rotating 6
A real image of the detector 25 is formed at , and in this embodiment the rotor 46 is integrated with the rotor of the scanning device 18 .
The real image of the station 45 is shown in FIG.
7 and the arrangement and direction of components (mirrors) 44, 45, and 47, it becomes conjugate with the real image 13 of the optical system 60. Also, the orientation of the rotor 46 with respect to the device 18 is
The said British Patent No. 2115174 for the purpose of causing a facet detection motion on the facets of 8.
is explained in. In use, returning again to FIG. 3, the system 10 includes a mirror 48 for refracting the optical path;
Including 49, 50, 51. System 10 in Figure 3
In this case, the real image 13 formed by the optical system 60 is not positioned on the surface of the concave mirror 20 in order to prevent dust on the mirror 20 or scratches on the surface of the mirror 20 from concentrating on the detector 25. Referring to FIG. 4, the optical system 60 has its optical axis 61 shown in a straight line, and the optical system 60 is separated from the residual shadow of the system 10 shown in FIG. show. A refractive optical system 60 is formed by lens elements M, N, P, Q, and R, and element M is an objective element.
A lens element is formed from the material to match the radius of the curved surface of the refractive surface, and the space of each conjugate refractive surface of the exit pupil 14 is formed by lens elements M, N, P,
Since it is outside the aggregate of Q and R, it is easy to enter the external real image 13, and the external real image 13 maintains a curved surface concentrating on the exit pupil 14. The table shows the parameters of the optical system 60 and, for each lens element, the symbols 1, 2 designate the refractive surfaces of the lens elements, and in each case the surface closest to the objective space 12, designated for example by lens element N, is designated by the symbol 1. It is a list. According to the invention, the concave mirror 20 has a curved surface that coincides with the locus of motion of the real image 13 caused by the scanning device 17. When the mirror 20 coincides with the locus, no optical aberrations are introduced and, as mentioned above, dust particles or surface defects are clearly imaged on the detector 25. When the concave mirror 20 is concentric with this locus, the magnification of the real detector image is independent of the position of the scanning locus (in the case of a radiation source), and by rotating the scanning device 18 at a constant speed, the real image of the detector is is also arranged to move at a constant speed. Placing a concave mirror 20 between the scanning locus and the scanning device 18 naturally makes the system 10 very compact, but the F- of the radiation beam in the region of the mirror 20 and the scanning device 17 makes the design of the optical system 11 quite difficult. The number is relatively small. When the scanning locus is placed between the concave mirror 20 and the scanning device 18, the mirror 20
The F-number of the radiation beam increases, which increases the arch distance of the optical system 11 but reduces the complexity of the optical design of the optical system 11. It should be noted that there is no example of separating the scanning locus from the concave mirror 20 by setting the focal length of the concave mirror 20. This is to collimate the resulting radiation beam. If the concave mirror 20 is not exactly concentric with the scan locus (considered as a radiation source) and the magnification of the detector 25 changes along the scan locus, and if the scan speed changes, the scan pupil will Since the imaging magnification can be independently selected, certain applications may be possible. Regarding the optical system 11 described in connection with the table and FIG. 4, the material used for the lens element is
It is an infrared transmitting material, either germanium (Ge) or chalcogenide glass, manufactured and sold by Barr & Stroud and labeled BS1.

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 is a side view showing a first embodiment of the radiation scanning/detection system of the present invention, FIG. 2 is a side view of the second embodiment, and FIG. 3 is a side view of the radiation detection system of the present invention. FIG. 4 is a side view showing a part of the third embodiment, and FIG. 4 is a side view showing another part of the system shown in FIG.
3 and 4 show the objective lens system or the scanning/detection system separately for clarity. 10... Radiation scanning/detection system, 11...
...Optical system, 12...Objective space, 13...External real image, 14...Exit pupil, 16...Scanning system, 17
...first scanning device, 18...second scanning device,
19...Conjugate pupil, 20...Concave mirror, 23...
Conjugate pupil forming device, 22...detection system, 24...
Conjugate image, 25...Detector, 28, 29, 30...
mirror.

Claims (1)

[Claims] 1. An optical system that receives scanning radiation,
an optical system that is provided with an exit pupil that is easy to enter and forms an external real image of the received radiation; and a scanning system that scans the radiation emitted by the optical system, and an optical conjugate imaging means for the exit pupil. and,
a scanning system comprising a first scanning device located in the exit pupil and a second scanning device further located in the conjugate pupil, the first and second scanning devices being arranged in mutually orthogonal scanning directions; a detection system for detecting radiation emitted by a detector, the detection system comprising an optical conjugate imaging means for the real image and a radiation detector located at the conjugate real image, the conjugate pupil imaging means comprising: A radiation scanning and detection system characterized in that it is a substantially spherical concave mirror located substantially concentrically with a detector real image locus imaged by a second scanning device when the detector is used as a radiation source. 2. The first scanning device is configured such that a plane flap mirror swings at a relatively slow speed to perform frame scanning, while the second scanning device is configured such that a rotor rotates at a relatively high speed to perform line scanning, and the rotor rotates at a relatively high speed to perform line scanning. 2. The system of claim 1, wherein the rotor has a planar reflective facet generally perpendicular to the axis of rotation of the rotor and integral with the circumference of the rotor. 3. The conjugate real image forming means is constituted by a simple transfer lens, and a second scanning device is installed between the lens and the detected real image formed by the conjugate real image forming means. The system described in Section 2. 4. The conjugate real image forming means is a transfer lens,
A radiation switching rotor substantially installed on the detection real image formed by the transfer lens, and a real image relay device in the form of a concave mirror, and the second scanning device is configured to connect the real image relay device and the relay real image formed here. The system according to claim 1 or 2, which is installed intermediately. 5. The real image of the detection locus imaged by the conjugate pupil forming means has a curved surface centered on the exit pupil, and the scanning locus imaged by the first scanning device is also centered on the exit pupil, whereby the axisymmetric optical system 5. The system according to any one of claims 1 to 4, which can utilize an external real image having a field curved surface centered on the exit pupil. 6. The detection real image locus imaged by the conjugate pupil forming means, the scanning locus imaged by the first scanning device, and the external real image of the optical system have a visual field curved surface commensurate with the compromise value of each locus. The system according to any one of Items 1 to 4. 7 Optical system with lens elements M, N, P, Q,
2. System according to claim 1, in which the element M is a symmetrical element and the parameters of the optical system are described in a table.