GB2245988A

GB2245988A - Telescopic sight of solid transparent material

Info

Publication number: GB2245988A
Application number: GB9111613A
Authority: GB
Inventors: Fraser Scott; Raymond George Budden
Original assignee: Ring Sights Ltd
Current assignee: Ring Sights Ltd
Priority date: 1990-05-30
Filing date: 1991-05-30
Publication date: 1992-01-15
Also published as: GB9111613D0; GB9011978D0

Abstract

A solid glass (or other transparent material) telescopic sight having a double prism image erecting system, comprises an objective lens 1 adapted to face a target, a graticule 5 disposed substantially at the focal length of the objective lens, a pair of orthogonally arranged prisms 6, 7 to erect the image, and an ocular lens 2 adapted to face an eye of the user. A third lens 4 disposed at the focal length and comprising a doublet lens having the graticule (5) between the components of a doublet lens or adjacent thereto, may be provided. <IMAGE>

Description

TELESCOPIC SIGHT The present invention relates to a telescopic sight. More particularly, it relates to a telescopic sight having a double prism image erecting system, and being cemented together into a solid transparent optical system.

It is known to provide sights having an image erecting system, hut such sights contain voids. It is necessary to purye such voids and fill then with dry nitroyen in order to maintain the usefulness of the sight.

It is an object of the present invention to provide a sight which is a solid unitary whole whereby such disadvantages may be overcome.

According to the present invention there is provided a telescopic sight comprising an objective lens adapted to face a target, a graticule disposed substantially at the focal length of the objective lens, a pair of othogonally arranyed prisms to erect the image, and an ocular lens adapted to face an eye of the user.

A third lens may be provided substantially at the focal length, said third lens comprising a doublet lens having the graticule between the components of a doublet lens or adjacent thereto.

Preferably, the graticule has an opaque pattern.

An embodiment of the present invention will now be more particularly described by way of' eample and with reference to the accompanying drawings, in which: Figure 1 is a side elevation of the sight; Figure 2 is a plan view of the siyht; and Figure 3 is an elevation of the taryet end of the sight.

Referring now to the drawings, there is shown a telescopic siyht which comprises a plurality of transparent units cemented together to form a unitary whole.

In the embodiment shown, an objective lens 1 and an ocular lens 2 each comprise a triplet arranyement of similar design it is possible that these lenses I and 2 need not: be triplets, but may be doublets or any other suitable converging lens arrangement Light rays passing from the target, through the objective lens 1, then pass through a solid block of transparent material 3 to a field lens/graticule arrangement 4, disposed at the focal length of the objective lens 1. In the embodiment shown, the field lens is a doublet arrangement with a graticule plate attached thereto at its front face.

The provision of the doublet field lens is not necessarily essential, and the graticule plate 5 may, if so desired, be located between the two lenses of the doublet arrangement, or on the eyeward facing side of the lens.

The graticule bears an opaque graticule pattern so that, as seen by the eye of the user, the graticule shows black against the target scene. Since it is disposed at the focal point of the lens, there is negligible parallax against the target scene.

The image is then erected by the light ray passing firstly through a first prism 6, reversing in a horizontal plane and then through a second prism 7, reversing in a errical lane. The light then passes to the ocular lens 2 and then co tulle eye of the user 8.

It is preferred that the overalllength of the sight is 91. mn in which case the ideal position for the eve of the user 8 is 64.4 mm from the ocular lens 2. The oral! cross sectional dimensions are preferably 25 mm acruss and 2 5 mm high.

Such a lens has a field of vie of 8" and an exit pupi diameter of 10 mm. Since the magnification is very close to unity, the views through and around the sight should match in the eye of the user.

The sight as described above may be mounted in a housing which can incorporate a means for zeroing.

Claims

CLAIMS:

1. A telescopic sight comprising a transparent objective lens adapted to face a target, a yraticule disposed substantially at the focal length of the objective lens, a pair of orthogonally arranged transparent prisms to erect the image, a transparent ocular lens adapted to face an eye of the user, and transparent means fixedly connectiny said lenses and prisms whereby the sight forms a unitary solid body.

2. A sight as claimed in claim 1, wherein a third lens is provided substantially at said focal length, said third lens comprising a doublet lens having the graticule between the components of said doublet lens.

3. A sight as claimed in claim 1, wherein a third lens is provided substantially at said focal length, said third lens conrising a doublet lens having the graticule adjacent to said doublet lens.

4. A sight as claimed in any one of the preceding claims, wherein the graticule has an opaque pattern.