DE3338496A1 - AFOCAL THERMAL DEVICE - Google Patents

Description

The invention relates to an afocal, designed as an attachment for an optical device, e.g. a visor Thermal imaging device, with an image pickup part in the infrared for generating electrical image signals, which is a Input optics, a scanning device and a detector "device, and with one, with the image pickup part connected image reproduction part for generating an image in the visible from the electrical image signals as well as with an output optics, wherein the image recording and reproduction part together form an imaging ratio by ^ i. : 1 have and their optical axes are aligned parallel.

A device of this type is known from DE-PS 26 23 399. This device assumes that a

2Q axis harmonization can be omitted if the opti- ' see axes of the receiving part and the reproducing part are parallel, since this is the only way that the afocal attachment device is insensitive to adjustment in relation to the downstream target device will. Such a parallelism can be created by installing the devices with the appropriate precision, however, maintaining this state can be particularly useful when the devices are used in rough conditions or when the Temperature differences cannot be guaranteed.

₃ Q It is therefore an object of the invention to provide an afocal thermal imaging device of the above type to provide, which enables easy Achsharmonisierung.

This object is achieved by a thermal imaging device designed according to the characterizing features of patent claim 1 solved.

MBB

Patent department

3338456

9442

10

15th

The axis harmonization takes place in the thermal imaging device according to the invention in a simple manner by means of an known shift of the image in the cathode ray tube until it appears on the screen Line mark is brought to coincide with the line mark applied on the outside of the screen. There the image of the infrared line mark, which is fixed in the beam path of the recording device, is displayed on the screen appears, if this mark is congruent with the one that is also permanently affixed to the cathode ray tube Line mark ensures the parallelism of the optical axes of the image recording and playback part. With further line marks attached outside of the optical axes, which cover the area are brought, the accuracy of the 1: 1 image can also be checked and, if necessary, checked Correct electrical adjustment of the image size.

The invention is described below with reference to an exemplary embodiment shown partially schematically in the figure.

A thermal imaging device 3 is arranged in front of the exit opening of a visor 1 with a directional mirror 2, which can be rotated together with the visor or the directional mirror, so that the optical axis 4 of the visor 1 is always parallel to axis 5 of the thermal imaging device. The thermal imaging device 3 consists of an image pickup part 3.1 and an image display part 3.2. The image recording part 3.1 essentially has infrared optics 6, a line mark 7 arranged in an intermediate image plane / effective in the infrared, a further infrared optics 8, an optical scanning device 9 and an infrared detector 10. When using a detector surface array the image field scanning would be purely electrical

BATH ORIGINAL

MBB

Patent department

9442

20th

25th

35

Ways take place.

The infrared radiation picked up by the detector is converted into visible radiation in one Image display part 3.2, which essentially comprises a cathode ray tube 11, a screen applied to its screen, the line mark 12 defining the optical axis 15, an output optics 13 and a partially transparent one Corner mirror 14 through which the image of the Cathode ray tube is reflected in the beam path 4 of the visor 1, has. The processing of the image signals of the detector 10 to video signals is done in a manner known per se and is therefore not shown in more detail in the exemplary embodiment. The optical axes 5 and 15 of the image recording and reproducing part 3.1 and 3.2 are aligned parallel to each other.

The, the optical axis 5 and thus the image center defining the IR line mark 7 is together with that of the Surroundings detected by IR optics 6 are imaged on detector 10 and thus appears by transmission to the cathode ray tube 11 on its screen. There on the Screen of the cathode ray tube 11 another that The line mark 12 defining the optical axis of the image display part 3.2 is firmly applied, can by comparison this figurative mark with the figurative mark appearing in the picture (= image of the IR line mark 7) the axis harmonization to be checked. Since the image of the cathode ray tube 11 by corresponding deflection voltages can be moved within the image plane, both line marks can be brought into congruence and thus an axis harmonization can be established.

An essential additional criterion for axis harmonization to other devices is that the

BATH ORIGINAL

Patent department

3 3 3 d 4 9

9442

Image capturing and reproducing part an aspect ratio of 1: 1. This can be checked and, if necessary, adjusted by adding to the IR line mark 7 a further line mark 7 'is arranged, for example in an image corner, which is marked with a corresponding line mark 12 'on the screen the cathode ray tube 11 corresponds. after the Line marks 7 and 12 have been made to coincide, can then be changed electronically to the image size the image of the mark 7 'with the mark 12' applied to the screen is also displayed on the screen Cover to be brought. This then ensures that the mapping ratio is precisely adhered to.

BATH

Claims (2)

PATENT CLAIMS 1. Afocal, designed as an attachment for an optical device, e.g. a visor, with an image recording part in the infrared for generating electrical image signals, which has an input optics, a scanning device and a detector device, and with an image reproduction part connected to the image recording part for generating a Image in the visible, from the electrical image signals as well as with an output optics, whereby the image recording and reproduction part together have an imaging ratio of 1: 1 and their optical axes are aligned in parallel, characterized by the following features:
a) the image recording part (3.1) has in the image plane or in an intermediate image plane of the input optics (6) a line mark (7) which defines its optical axis (5) and is effective in the infrared, b) the image display part (32) has a cathode ray tube (11) on, c) is on the screen of the cathode ray tube (11) a line mark which defines the optical axis (15) of the image display part (32) and is effective in the visible (12) applied and d) the line mark appearing on the screen as an image of the image recording part (3.1) is through electrical Shifting the image in the cathode ray tube (11) with that applied to the screen Line mark (12) harmonized. 35 3338436 Patent department 9442 2. Afocal thermal imaging device according to claim 1, characterized in that in addition to the line marks (7,12) of the image recording and reproducing part (3.1, 3.2) defining the optical axes (5, 15), at least one further outside the respective ^{Line mark (7 1} , 12 ') that is arranged on the optical axis and harmonized with one another is provided. ÖAD ORfGiNAL