DE2623399A1 - SPECTRAL CONVERTER AS ADD-ON DEVICE - Google Patents

Description

Dipl.-Ing. leonhari Reichert, Nussloch

Spectral converter as an attachment

The invention relates to an afocal spectral converter as Attachment for existing aiming and straightening devices for conversion for example a »färmeoildes into a visible one Image. The front-end device should be designed in such a way that it can be attached in front of the main device without adjustment can without changing the aiming direction of the aiming or viewing device.

Afocal attachments are known from geometrical optics, the task of which is to carry out a magnification changeover. All of these attachments cause a change in the target direction if the optical axis of the telescopic sight does not coincide with the optical axis of the afocal attachment. Only with a magnification of 1: 1 and with parallelism of the entry and exit beams, such an attachment does not determine the direction of the target even if the optical axis of the attachment does not coincide with the optical axis of the telescopic sight. In visual optics, however, attachments with a magnification of 1: 1 are of no interest because they have no optical effect.

The invention is based on the object of providing an afocal spectral converter as an attachment of a simple, lightweight construction to create where the incoming IR rays converted into visible rays that can be observed through the main unit. Here the view should are not affected by the main unit.

According to the invention, an afocal spectral converter is designed as an attachment for existing straightening devices in such a way that

709849/0260

BATH ORIGINAL

~ i ~ 2623389

an infrared image recording unit is combined with an image reproduction unit in the form of the overall system
has the magnification 1: 1, that the connection of the attachment to the main unit is such that the optical axis of the image recording unit runs parallel to the optical axis of the main unit, and that the parallel bundle of rays of the image display unit so into the The main device is reflected in such a way that the main device is not influenced.

i-

the

709849/0260

(directly after page 2), -, ~ ~ ο η Ω

2623333

In the .Bauart according to the invention, the conversion of thermal to visible radiation with no efficiency based on the principle of a frequency converter. By enlarging 1: 1 it is achieved that in the parallel beam path the contours of the thermal image correspond exactly to the visible image and daner decicuxigsgxexoii can be reflected with this. the The parallelism of the optical axis of the image pickup unit with the optical axis of the main unit enables the parallel To reflect the beam of the image display unit into the main unit in such a way that the main unit is not influenced.

The principle underlying the invention allows a normal Operation during the day, whereby the thermal image is reflected in the visible on the same scale and contour-covering. Ea This creates a mixed image in which the red and green spectral lines with their thermal content in the visible spectral range are displayed. The thermal image is in adjustable in intensity. The mixed image combines the advantages of daytime vision with those of thermal vision. For example, are Easily identify optically camouflaged targets in the thermal area.

If you train the device so that the optical axis is reproduced Unit runs parallel to the optical axis of the image recording unit, so one can use one to record the thermal image Set the polygonal prism with the polygonal prism writing the visible image on a common shaft and thereby in both Palls enable exactly synchronous sampling, .uie conversion the heat signals picked up by a detector into an optical one Image can be carried out in a manner known per se via one or more luminescence diodes /.

From the geometrical optics, afocal attachments are used to switch the magnification known. All of these intentions cause a change in the direction of the target, if not the optical axis of the Telescopic sight coincides with the optical axis of the afocal attachment.

With a magnification of 1: 1 and with parallelism, the entry and Exit rays, such an intent changes the target

109949/0260

-4-

SUBMITTED

there resolutions

262339

Direction not even if the optical axis of the attachment does not coincide with the optical axis of the main unit.

ijje ;; e basic idea applied to a thermal image means that the ■ Image pickup unit and the image display unit of a thermal imaging device are designed to each other so that the overall system has the magnification 1ß1 and the optical axis of the image pickup unit runs parallel to that of the picture display unit.

Thus, on the same optical axis, the IR beam entering at the angle \ is reversed into the plane of an IR detector. ilach conversion of IR radiation into visible to the eye radiation over luminescence diodes, the rays exit at the same angle i <the header (converter), and can-device target occur in a suitable manner in the entrance pupil of an optical sealing or. This fulfills the condition for EaIl by entering a parallax-free system, namely that the axis of the attachment for the beam entry and exit runs parallel and is thus independent of the adjustment to the main device.

It is therefore also an essential feature of the device according to the invention that there is only an offset of the field of view in the thermal image When observed through the sight of the main unit shows without affecting the aiming accuracy if the sighting line of the main device does not exactly match that of the attachment.

Of course, an adaptation of the WärmeDild converter can in principle also take place in separate i'upillen. Then it should be ensured that the internal device angle of the main device with the • Angle of the attachment for the entry and exit of the beams is identical.

With normal polygonal prisms, the line offset must be effected with the help of an additional element, e.g. a tilting mirror. The line offset can be made easier and easier by using of a polygon with set lateral surfaces. Each lateral surface of such a polygonal prism senses one from the other line of the overall picture, Su uaß that with one turn The entire image is scanned from left to right and from top to bottom. By corresponding v '/ ahl the setting angle of the side the axis of the prism can also be represented by

709849/0280

-5-

generate a coarse-fine grid. This means that the goals which normally have a higher temperature than the subsurface, appear coarse while the background is green.

In order to be able to readjust the parallel position of the recording unit and the playback unit of the device if necessary, it is It is expedient that an element for the parallel adjustment is arranged in one of the two optical channels.

The reflection of the visible thermal image in the The main device takes place via a spectral splitter which, when the front-end device is attached, is in front of the entrance pupil of the main device is arranged. This spectral splitter is designed so that it lets through rays of the visible range and those from the luminescent diodes outgoing rays reflected. This means that daytime visibility is not obstructed by the main unit and that by the front-end unit But coming rays are reflected and into the beam path of the main device. The thermal image made visible is superimposed on the one perceived by the main device, natural picture.

Together with the main unit, the front-end unit forms an overall dination. both as a day vision device and as an Elachtoichtgorät can be used / grounded. Even with normal daytime operation, the thermal can be seen on the same scale Image can be reflected. At dawn or hazy weather, target tracking is done with the pure day vision device sometimes suddenly disturbed, so that the desire arises to switch on the night vision device. In these cases it is useful if the attachment can be attached to the main unit in just a few simple steps and can be attached to it. It will therefore continue proposed the device with an easily detachable fastening element to connect to the main unit.

The pictures show:

Fig.1 shows in schematic form the operation of the device in Assembly with the main unit;

2 the 'optical structure of the front attachment schematically;

Fig. 3 the attachment of the device to a standard observation and Target device.

Pag Versat? Gerä ^ -fcestehfr-Äus-Äwei -iiiaheü «», - d & ^ - recording ·

709849/0260

I SUBSCRIBED TO J

The attachment consists of two units, the recording unit 1, in which the IR rays emitted by the object are scanned and fed to the detector, and the v / ieder unit 2, in which the rays emitted by the luminescent diodes are combined into an image and passed on, üie dividing line 6 represents the entire electronics, in which the conversion of the recorded IR rays via a video signal and luminescent diodes is made into visible rays. The incoming IR rays 17 are initially through the mirror 15 deflected, then focused through the lens group 11/21 and thus arrive at the detector. The grain of the luminescent diodes Menden visible rays are in the collimator Ίη parallel Beams are converted and thus arrive at a spectral splitter 3 »which they pass through the exit opening 32 and the entrance pupil 41 reflected in the beam path of the main unit. The optics of the basic device are denoted by 46. The beam splitter 3 is like this designed so that it transmits the natural visible rays and reflects the rays coming from the luminescent diodes. Opposite the exit opening 32 is an entrance pupil 31 arranged by showing the visible rays in the front attachment can enter. In this way, the (J-round device recognizable, natural image is superimposed on a thermal image that shows the different temperatures occurring on the observed object displays in different colors. The 1: 1 magnification ensures that both images are congruent.

Figure Z shows the internal structure of the front attachment schematically. The entry lens is designated by 11. 12 is a polygonal prism, which sits on a 22 v / elle with a second polygonal-prism and is driven by a common motor ⁵ Ir T. As a result, an exactly synchronous Dr.efto movement of the two i'o ± _< y & «jnal prisms is achieved. Behind the polygonal i'rism 12 is a transformation optics 13 is arranged, from which the incoming IR rays are fed to a detector 14. The IR rays recorded by the detector are converted into visible rays in a manner known per se via a video signal and luminescent diodes 24. The visible rays emanating from the luminescent diodes reach the polygonal

JO9849 / 02S0 - 7 -

Prism 22, which writes the visible thermal image, and then Via a collimator 23 to a deflecting mirror 25. The deflecting mirror 25 reflects the rays and guides them to the ripectral splitter 3, from which they are reflected in the beam path of the basic device in the manner described. In the case that surrounds the spectral splitter 3, an exit opening 32 is provided for this purpose. Located opposite the outlet opening 32 an entry opening 31 for the visible rays, which after passing through the spectral splitter 3 also in reach the entrance pupil of the basic device. There is a hole 33 in the beam splitter for testing purposes.

Figure 3 shows the attachment of the attachment 5 to the basic device 4 can be seen. The same designations apply to the parts already discussed as in the previous illustrations. A deflecting prism 42 is arranged behind the entrance pupil 41 of the basic device, which deflects the beams and a second deflecting prism 43. After being deflected again by the prism 43, the rays enter the eyepiece 44.

909849/0260

Blank page

Claims (8)

Claims 1./Afocal spectral converter as an attachment for existing ■ target and directional devices for converting, for example, a thermal image into a visible image, characterized by the combination of an infrared image recording unit with an image reproduction unit such that the overall system has the magnification 111 further characterized in that the connection of the attachment to the main unit is such that the optical axis of the image pickup unit runs parallel to the optical axis of the main unit, and that the parallel beam of rays from the image display unit is reflected into the main unit, that there is no influence on the main unit. 2. Spectral converter according to claim 1, characterized in that the optical axis of the image display unit runs parallel to the optical axis of the image recording unit. 3 »Spectral converter according to claims 1 and 2, characterized by the combination of a rotating polygonal prism for Cartesian scanning of the thermal image in the beam path of the recording unit with a polygonal prism for converting the electrical signals emitted by the recording unit into a visible image in the beam path of the playback unit in such a way that both sit on a shaft which is driven by a common drive motor. 4. spectral conversion according to claims 1 to 3 _f marked in terized in that the two polygonal prisms are formed as geschränkte polygonal prisms * 709849/0280 5. Spectral converter according to claim 3 « characterized in that the group consisting of the polygonal prisms and their drive motor is mounted tiltably around an axis that intersects the axis of the drive shaft and is perpendicular to it and is equipped with an electric drive to generate the tilting movement . 6. Spectral converter according to one or more of claims 1 to 5 » characterized in that an element for parallel adjustment is arranged in one of the two optical channels. 7. Spectral converter according to one or more of Claims 1 to 6, characterized in that a beam splitter and / or a spectral splitter is arranged in the parallel beam path of the image display unit. 8. Spectral converter according to one or more of claims 1 to 7 _t, characterized in that the device is equipped with an easily detachable fastening element for connection to the main device. 709849/0260