GB2193817A - Collimator device - Google Patents

Abstract

A collimator device useful for optical sighting and alignment comprises (a) a positive lens or lens system 10 as eyepiece, (b) a graticule 14 having a reflective or semi-reflective surface and a central transparent sighting portion 18, (c) a barrel 12 whereby the graticule is fixed in the focal plane of the lens and (d) a cover 20 fixed over the outside of the graticule to exclude ambient light. The graticule 14 is of glass silvered on its rear surface 16 except at the cross-shaped sighting portion 18. A self-illuminating capsule 22 can be mounted to fit beneath the cover over the graticule end of the barrel, for use in darkness. A pyramidal prism 24 can be placed over the eyepiece, to allow alignment in multiple directions to be checked simultaneously. One of the user's eyes views through the device; the other views the target. When the system is in collimation the marked portion 18 on the graticule stays stationary in relation to the target when the head is moved. <IMAGE>

Description

SPECIFICATION Collimator device This invention relates to an improved collimator which is useful for optical sighting and alignment. The device may be used to sight or align accurately by eye on to a target or mark, either in daylight or in darkness.

Known devices of this type have some form of graticule (or reticule), which hitherto have had an opaque image on a clear background, or in use require background light to allow the image to be seen. We have devised a new form of such device with a different form of graticule.

According to the invention we provide a collimator device useful for optical sighting and alignment which comprises (a) a positive lens or lens system as eye-piece, (b) a graticule having a reflective or semi-reflective surface and a central transparent sighting portion, (c) a mounting means whereby the graticule is fixed in the focal plane of the lens or lens system, and (d) a cover fixed over the outside of the graticule.

In practice, the graticule is conveniently made of glass which is on one surface silvered, aluminised or otherwise made reflective except at the sighting portion.

For use in darkness, the device also comprises a self-illuminating capsule which is removably mountable on the device outside the graticule.

The invention will be further described by reference to the preferred embodiment thereof shown in the accompanying drawing, wherein; Figure 1 is a longitudinal section of an embodiment of the device according to the invention; and Figure 2 is a view of the graticule of the device of Fig. 1.

An optical lens (eyepiece or viewing lens) 10 is mounted as eye-piece at one end of a barrel 12, at the other end of which is fixed, in the focal plane of the lens, a graticule 14 which made of a disc of glass silvered on its rear face 16 having a clear cross-shaped area 18 in its centre. Thus the clear marking is surrounded by a reflecting surface.

For use in darkness, a removable cover 20 containing a self-illuminating capsule 22 is placed over the end of the device to cover the graticule.

The barrel 12 does not have to be solid but could be an open framework. The graticule does not have to be fully reflective, and its surface could be semi-reflective, provided that sufficient light is reflected back through the eye piece.

The device is used as follows. One of the user's eye's views through the device, simultaneously the other eye views the object or target. When the optical system is set correctly in collimation, the marking 18 on the graticule 14 will remain stationary in relation to the target when the head is moved (a situation of no parallax).

When used in daylight, ambient light is reflected from the user's eye through the positive lens or lens system onto the reflective surface of the graticule and back through the lens or lens system into the eye. Due to the small amount of reflection from the clear part of the graticule this appears dark against the brighter background produced by the fully reflective surface.

If the device is used without the cover and self-illuminating capsule, in daylight the transparent sighting portion seen by the eye is bright. With the cover on, but with no selfilluminating capsule fitted, in daylight the transparent sighting portion is dark. With the cover on and the self-illuminating capsule fitted, in daylight the transparent sighting portion is dark, but in darkness this portion is seen because the self illuminating capsule emits light which the eye sees. The device functions with the cover either on or off.

In darkness there is little or no ambient light to be reflected from the operator's eye and the fully reflective part of the graticule appears dark. The self-illuminating capsule glows and the emitted light passes through the clear part of the graticule and is clearly seen by the operator's eye.

The device can be incorporated into any known aiming or maligning device, into a fire arm (e.g. a rifle or pistol) as the sight, and can also be used for aligning of floodlights, airfield runway and taxiway edgelights, or searchlights, and for setting out points at predetermined angles and/or positions.

If a pyramidal prism is placed over the eyepiece, alignment in four 90" directions can be checked simultaneously; such a prism is shown in dotted lines 24 in the drawings. If an angle setting device is also incorporated, the "toein" and "toeout" of airfield lights can be checked, by rotating the prism and the device about a common centre.

Further uses are as follows. Whereas our device is set to infinity any target inside the infinity range of the device will show parallax.

Either by the use of separate lens elements or by making the lens system focusable, targets inside the infinity range could be sighted accurately. This modification could apply to all applications described above.

The device can also be used for measurement of distances, angles, heights and levels.

A further advantage is that the device gives good eye distance relief, since the observing eye may be placed a considerable distance away from the lens or lens system. It is this feature which allows the use of the pyramid prism, whereby all five images can be seen simultaneously.

The self-illuminating capsule 22 can conveniently be a tritium-gas-filled unit, and in such a case it should not be easily removable, in view of the slight risk to health from the minute levei of radioactivity. If the capsule is otherwise constructed there is no problem with the capsule and cover being removable.

The cover is desirably kept fitted to protect the graticule from damage or dirt.

Claims (5)

1. A collimator device useful for optical sighting and alignment which comprises (a) a positive lens or lens system as eye-piece, (b) a graticule having a reflective or semi-reflective surface and a central transparent sighting portion, (c) a mounting means whereby the graticule is fixed in the focal plane of the lens or lens system and (d) a cover fixed over the outside of the graticule to exclude ambient light.

2. A device as claimed in Claim 1, wherein the graticule is made of glass which is reflective on one surface except at the sighting portion.

3. A device as claimed in Claim 1 or 2, together with a seif-illuminating capsule mounted to fit over the graticule end of the barrel, for use in darkness.

4. A device as claimed in Claim 1, 2 or 3, together with a multi faced prism adapted to be placed over the eyepiece, to allow alignment in multiple directions to be checked simultaneously.

5. A collimator device subsequently as hereinbefore described with reference to the accompanying drawing.