JPS62265614A - Radiant scanning/detection system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field 1] The present 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 known, which are designed to receive collimated light from a distant scene, Miniaturization of the system 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 an l@+ line scanning/detection system having the following configuration. In other words, it is an optical system that receives scanning radiation and is easy to enter.
ssible) an optical system comprising an exit pupil and forming an external real image of the received radiation; and a scanning system that scans the radiation emitted by the optical system, the optical conjugate imaging means of the exit pupil. a scanning system comprising: a first scanning device located in the exit pupil; and a second scanning device 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 the system, the detection system comprising optical conjugate imaging means for the real image and a radiation detector located at the conjugate real image; is characterized in that it constitutes a substantially spherical concave mirror located substantially concentrically with the detector real image locus imaged by the second scanning device when the detector is used as a radiation source.

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 scans the frame by swinging at a relatively slow speed;
The cylinder two scanning device is preferably configured in a line scanning manner with a rotor rotating at a relatively high speed, said rotor being generally substantially perpendicular to the axis of rotation of the rotor and having planar reflective facets integral with the circumference of the rotor. are doing.

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 composed of a transfer lens, a radiation switching rotor that is substantially installed on the detected 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. 2,115,174, 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 scan locus imaged by the first scan %NH 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 the exit pupil. If the loci have different curved surfaces, preferably the external real image of the optical system has a visual field curved surface commensurate with 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.
Contains. This optical system 11 receives radiation (for example, infrared rays) from an objective space 12, and is made up of refractive optical elements for forming a real image 13 into which the received radiation is likely to enter into the image space of the optical system. , this optical system 11 has an exit pupil 14 through which the radiation PAID passes before the arriving real image 13. Further, an optical system 11 is formed by lens elements A, B, C, and D arranged on a common optical axis 9, and this optical system 1
The locus of a radiation ray passing through 1 is expressed by a selected radiation ray bundle.

The radiation traversing the optical system 11 is subject to orthogonal scanning by a radiation scanning system 16, said radiation scanning system being conjugated with the exit pupil 14 and a first scanning device 11 in the form of a swinging flap mirror located in the exit pupil 14. a second scanning device 1 in the form of a polyhedral rotor, formed by a substantially spherical concave mirror 20 located in the pupil 19 and forming part of the scanning system 16, and located in the configuration described above;
It consists of 8.

After the scanning system 16, the radiation is collected in a detection system 22 which includes a device 23 for imaging the optical conjugate of the real image 13 at a station 24 and a radiation detector 25 located at the station 24. When the detector 25 is used as a radiation source, the detected real image formed by the device 23 is moved by the scanning device 18 to a conventional circular locus, and the conjugate pupil in the form of a concave surface 1' 120 is located almost centrally at the real image locus. Due to the focal nature of the optical system 11, the concave mirror 20 may be located close to or located at the real image locus, omitting the angular range of the mirror 20 and 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. In actual use, the radiation passing through the system 10 is reflected by the refracting mirror 2.
8. Refract at 29.30. The scanning device 18 is located in its own housing with gas bearings and a window 31 through which radiation passes. 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 #AG, a mirror surface H formed on a part of the element F, and a lens element i.
Configure L in SJ.

In each of the embodiments of FIG. 1.2, the device 23 for imaging the optical conjugate of the real image 13 is in the form of a simple transfer lens; in the arrangement shown in FIG.
．． 115.174. Thus, in FIG. 3, transfer lens 44 forms a real image of detector 25 at station 45, which rotates past polyhedral radiation switching rotor 46, which in this embodiment is rotor 46 of scanning device 18. Become one with. The real image of the station 45 is conjugate with the real image 13 of the optical system 60 due to the arrangement and orientation of the substantially spherical concave mirror 47 and the components (mirrors) 44, 45, 47, as shown in sections in FIG. 4 for clarity. . The orientation of the rotor 46 with respect to the device 18 is also described in the aforementioned British Patent No. 2.115.174 for the purpose of creating a facet sensing motion on the facets of the scanning device 18. In use, returning again to FIG. 3, system 10 includes mirrors 48, 49, 50, 51 for redirecting optical paths. In the system 10 of FIG. 3, the real image 13 formed by the optical system 60 is not located on the surface of the concave mirror 20 in order to prevent dust 120 or the like from concentrating on the detector 25.

Regarding the aT4 diagram, the optical system 60 has its front axis 61
is shown in a straight line, and the optical system 60 has an exit pupil 14 and a real @1
3 is not shown in FIG. 3 for clarity, and is shown separately from the residual image of the system 10. A refractive optical system 60 is formed of lens elements (11N, P, Q, and R), element H is an objective element, and a lens element is formed from the material to match the radius of the curved surface of the refractive surface, and the exit pupil 14 is The spaces of each conjugate refractive surface are lens elements H, 81P, Q,
As a result, since it is outside the aggregate of H, 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. Table I shows the parameters of the optical system 60 and for each lens element the refractive surface of the lens element is designated by the symbol 1.2, and in each case the surface closest to the objective space 12, designated for example by the lens element N, is designated by the symbol 1. This is the list shown.

According to the invention, the concave mirror 20 has a curved surface that corresponds to the trajectory of the real image 13 caused by the scanning device 17. When the mirror 20 coincides with the locus, no optical aberration is introduced, and as mentioned above, dust particles or surface defects are detected by the detector 2.
5 is clearly imaged. Concave! ? When 120 is concentric with this locus, the magnification of the detector real image is (when used as a radiation source)
Independently of the position of the scanning locus, the scanning device @18 is rotated at a constant speed and the detector real image is also arranged to move at a constant speed along the real image by the concave mirror 20. Concave surface 120
Placing the system 10 between the scanning locus and the scanning device 18 naturally makes the system 10 very compact, but it also makes the design of the optical system 11 much more difficult! 1!20 and the F-number of the radiation beam in the area of the scanning device 11 is relatively small.

Placing the scanning locus between concave surface Wt 20 and scanning arrangement 218 increases the F-number of the radiation beam, which increases the arch distance of mirror 20 but reduces the complexity of the optical design of optical system 11. By setting the focal length of the concave surface lA20, the scanning locus can be set on four planes t? It should be noted that there are no examples of isolation from I20. 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 magnification for imaging can be independently selected, certain applications may be possible.

Regarding the optical system 11 shown in Table 1 and FIG. It is the material.

Table I Note 2: All dimensions are 1II C = concave V = convex Book = aspherical surface

[Brief explanation of drawings]

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.
The figure is a side view showing a part of the third embodiment of the radiation detection system of the present invention, and FIG. 4 is a side view showing another part of the system shown in FIG. The figure shows the objective lens system or the scanning/detection system separated for clarity. 10... Radiation scanning/detection system 11... Optical system 12... Objective space, 13... External real image 1
4...Exit pupil, 16...Scanning system 17...
First scanning device, 18...Second scanning device 19...
Conjugate pupil, 2o... Concave mirror 23... Conjugate pupil forming device, 22... Detection system 24... Conjugate image,
25...Detector 28.29.30...Kagami Barr & Stroud Limited agent (7
134) Patent attorney Naoe Ashida (7222) Patent attorney Masayuki Asakura
month day

Claims (1)

[Scope of Claims] 1. An optical system that receives scanning radiation and is provided with an exit pupil that allows easy entry of the radiation and forms an external real image of the received radiation; a scanning system for scanning a radiation ray comprising: an optical conjugate imaging means of the exit pupil; a first scanning device located in the exit pupil; and a second scanning device located in the conjugate pupil; Said first,
a scanning system in which second scanning devices are arranged in scanning directions orthogonal to each other; and a detection system for detecting radiation emitted by the scanning system, the optical conjugate imaging means for the real image and the radiation located in the conjugate real image. a detection system comprising a detector, the conjugate pupil imaging means being substantially concentric with the detector real image locus imaged by the second scanning device when the detector is the radiation source; A radiation scanning and detection system characterized by a spherical concave mirror. 2. The first scanning device has a configuration in which a plane flap mirror swings at a relatively slow speed to perform frame scanning, while the second scanning device has a configuration in which a rotor rotates at a relatively high speed to perform line scanning; 2. The system of claim 1, wherein the rotor has planar reflective facets that are generally substantially perpendicular to the axis of rotation of the rotor and are 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, or The system according to paragraph 2. 4. The conjugate real image imaging means is composed of a transfer lens, a radiation switching rotor that is installed substantially 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 form a real image. The system according to claim 1 or 2, which is installed between the relay device and the relay real image formed thereon. 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, thereby creating an axisymmetric optical system. , a 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 paragraphs 1 to 4. 7. System according to claim 1, in which the optical system is formed by lens elements M, N, P, Q, R, element M is a symmetrical element, and the parameters of the optical system are set out in Table I.