GB2068584A - Reticule For Camera Viewfinder - Google Patents

Abstract

The illuminated reticule is disposed in the focal plane of an optical viewing device and is provided with any desired marking, preferably with field marks for the viewfinder of a camera. To permit an illumination of the reticule without need for a beam splitter, marking lines (3) are scribed or etched on the reticule and the reticule provided with the marking is artificially illuminated by light emitted onto its edge by at least one lamp (2). <IMAGE>

Description

SPECIFICATION Reticule for Optical Viewing Devices This invention relates to an illuminated reticule, which is disposed in the focal plane of an optical viewing device and is provided with any desired marking, preferably with field marks for the viewfinder of a camera.

In so-called bright-frame viewfinders of cameras, the field is indicated by a frame, which is brightened by daylight. Such reticules in optical viewing devices may have to be used when no daylight is available or when the daylight which is available is inadequate, for instance, in cameras to be used at night. For such cases, means for an artificial illumination of the reticules or field masks are known and an illumination of the reticule is ensured in that an existing field mask which is artificially illuminated and has the required marking is injected by a beam splitter into the path of the device with the same focus as the actual optical image.

U.S. Patent Specification 41 01 916 discloses a reticule provided with reflecting lines which have been applied by vapor deposition. By means of a beam splitter disposed in the viewing device, these lines are so illuminated that the viewer sees the illuminated reflecting marking. It is an object of the invention so to improve a reticule of the kind described first hereinbefore that it is illuminated without the use of a beam splitter.

In a reticule of the kind described first hereinbefore, this object is accomplished in that marking lines are scribed or etched on the reticule and the reticule provided with the marking is artificially illuminated by light emitted onto its edge by at least one lamp. The reflecting lines emit light because they are recessed and are illuminated from the periphery. The reticule is illuminated at its periphery approximately at right angles to its thickness.

For a maximum utilization of the light which is emitted by the reticule because the light reflected from the scribed or etched lines falls into the viewer's eye, the marking of a preferred embodiment of the reticule is provided on that side which faces away from the viewer.

According to a preferred further feature of the invention, the reticule is provided on both sides with antireflection coatings. This wiil avoid the disturbing reduction of contrast known from the reticules of the state of the art.

The means for illuminating the reticule may consist of one or more miniature lamps or, for larger reticules, may consist of an externally disposed annular lamp. For special purposes, the reticule may be illuminated by currentless beta light.

An embodiment of the invention will be explained by way of example hereinafter with reference to the accompanying drawing, in which: Figure 1 is a top plan view showing a reticule according to the invention and Figure 2 is a diagrammatic view showing an illuminating device and a reticule according to the invention.

The reticule 1 is illuminated by four lamps 2, which emit light onto the edge of the reticule at right angles to its thickness. The reticule 1 has a scribed or etched marking 3.

The sectional view of Figure 2 indicates the recessed lines 3 on that side 4 of the reticule 1 which faces away from the viewer. Reference numbers 5 designate the symbols for the anti reflection coatings provided on both sides of the reticule 1. Other parts of the viewing device consist of a field lens 6 and a viewing eyepiece 7.

The viewer's eye is designated 8.

In the embodiment shown by way of example on the drawing, the reticule consists of glass.

Claims

1. An illuminated reticule, which is disposed in the focal plane of an optical viewing device and is provided with any desired marking, preferably with field marks for the viewfinder of a camera, characterized in that marking lines are scribed or etched on the reticule and the reticule provided with the marking is artificially illuminated by light emitted qnto its edge by at least one lamp.

2. A reticule according to claim 1, characterized in that the marking of the reticule is provided on that side which faces away from the viewer.

3. A reticule according to claim 1 or 2, characterized in that the reticule is provided on both sides with antireflection coatings.

4. An illuminated reticule for an optical viewing device constructed and arranged substantially as hereinbefore described and shown in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Reticule for Optical Viewing Devices This invention relates to an illuminated reticule, which is disposed in the focal plane of an optical viewing device and is provided with any desired marking, preferably with field marks for the viewfinder of a camera. In so-called bright-frame viewfinders of cameras, the field is indicated by a frame, which is brightened by daylight. Such reticules in optical viewing devices may have to be used when no daylight is available or when the daylight which is available is inadequate, for instance, in cameras to be used at night. For such cases, means for an artificial illumination of the reticules or field masks are known and an illumination of the reticule is ensured in that an existing field mask which is artificially illuminated and has the required marking is injected by a beam splitter into the path of the device with the same focus as the actual optical image. U.S. Patent Specification 41 01 916 discloses a reticule provided with reflecting lines which have been applied by vapor deposition. By means of a beam splitter disposed in the viewing device, these lines are so illuminated that the viewer sees the illuminated reflecting marking. It is an object of the invention so to improve a reticule of the kind described first hereinbefore that it is illuminated without the use of a beam splitter. In a reticule of the kind described first hereinbefore, this object is accomplished in that marking lines are scribed or etched on the reticule and the reticule provided with the marking is artificially illuminated by light emitted onto its edge by at least one lamp. The reflecting lines emit light because they are recessed and are illuminated from the periphery. The reticule is illuminated at its periphery approximately at right angles to its thickness. For a maximum utilization of the light which is emitted by the reticule because the light reflected from the scribed or etched lines falls into the viewer's eye, the marking of a preferred embodiment of the reticule is provided on that side which faces away from the viewer. According to a preferred further feature of the invention, the reticule is provided on both sides with antireflection coatings. This wiil avoid the disturbing reduction of contrast known from the reticules of the state of the art. The means for illuminating the reticule may consist of one or more miniature lamps or, for larger reticules, may consist of an externally disposed annular lamp. For special purposes, the reticule may be illuminated by currentless beta light. An embodiment of the invention will be explained by way of example hereinafter with reference to the accompanying drawing, in which: Figure 1 is a top plan view showing a reticule according to the invention and Figure 2 is a diagrammatic view showing an illuminating device and a reticule according to the invention. The reticule 1 is illuminated by four lamps 2, which emit light onto the edge of the reticule at right angles to its thickness. The reticule 1 has a scribed or etched marking 3. The sectional view of Figure 2 indicates the recessed lines 3 on that side 4 of the reticule 1 which faces away from the viewer. Reference numbers 5 designate the symbols for the anti reflection coatings provided on both sides of the reticule 1. Other parts of the viewing device consist of a field lens 6 and a viewing eyepiece 7. The viewer's eye is designated 8. In the embodiment shown by way of example on the drawing, the reticule consists of glass. Claims

1. An illuminated reticule, which is disposed in the focal plane of an optical viewing device and is provided with any desired marking, preferably with field marks for the viewfinder of a camera, characterized in that marking lines are scribed or etched on the reticule and the reticule provided with the marking is artificially illuminated by light emitted qnto its edge by at least one lamp.

2. A reticule according to claim 1, characterized in that the marking of the reticule is provided on that side which faces away from the viewer.

3. A reticule according to claim 1 or 2, characterized in that the reticule is provided on both sides with antireflection coatings.

4. An illuminated reticule for an optical viewing device constructed and arranged substantially as hereinbefore described and shown in the accompanying drawings.