GB2130388A

GB2130388A - An arrangement of display indicators for reflex cameras

Info

Publication number: GB2130388A
Application number: GB08329379A
Authority: GB
Inventors: Rolf Jurenz
Original assignee: Pentacon Dresden VEB
Current assignee: Pentacon GmbH Foto und Feinwerktechnik
Priority date: 1982-11-04
Filing date: 1983-11-03
Publication date: 1984-05-31
Also published as: GB8329379D0; GB2130388B; DD211191A1; DE3331295A1; FR2535861B1; FR2535861A1

Abstract

An arrangement of display indicators in the viewfinder system of reflex cameras is provided in which the display indicator (3), in conjunction with at least one optical component (2) is arranged, directly in the shooting direction or directly behind the cover hood (4), at the top obliquely towards the front. The reflection ray path extends approximately parallel to the image erecting surface of the pentagonal prism (1), there being effected in the further ray path a real projection of the display in the viewfinder image plane. <IMAGE>

Description

SPECIFICATION An arrangement of display indicators for reflex cameras The invention relates to an arrangement of display indicators in the viewfinder system of reflex cameras.

The arrangement of display indicators in the form of scales, symbols, pointers, marks, LED and LCD displays in the viewfinder system of reflex cameras is as a rule in the vicinity of the viewfinder image plane between the image field lens and the pentagonal prism, possibly with the insertion of optical deflection means, or fitting is effected directly on the image field lens. Unless such indicators are selfluminous devices, such as LED displays, their visibility in the viewfinder image plane is dependent on the illumination conditions prevailing at the indicator location. If there is a dark object detail at this point, then the indicator is inadequately or not discernible.

There are also known arrangements where the reflection of such indicators is effected with additional optical aids from a plane that is equivalent to the viewfinder image plane. This results in more favourable illumination conditions, but it is disadvantageous that so-called finder hood viewing cannot be excluded, which, unless one looks exactly centrically into the viewfinder, leads to a more or less vignetted reflection field. This means that the indicator is only visible without any disturbance if the observation conditions are clearly defined.

It is the object of the invention to improve the presentation of indicator displays in the viewfinder image plane of reflex cameras.

The task underlying the invention is to reflect indicators which are not self-luminous in an easily discernible manner into the viewfinder ray path, along with a space-saving arrangement of optical components, and to display the reflection field without any vignetting.

According to the invention, the problem is solved in that the display indicator, in conjunction with at least one optical component, is arranged, directly in the shooting direction or directly behind the cover hood, at the top obliquely towards the front and in that the reflection ray path extends approximately parallel to the image erecting surface of the pentagonal prism. Subsequently, there occurs a real projection of the display in the viewfinder image plane. It is advantageous if the optical component is a reflecting prism which is arranged upstream or downstream of the display indicator and allows the reflection ray path to be deflected parallel to the image erecting surface of the pentagonal prism.For solving the problem, it is also favourable if one surface of the optical component arranged in front of the display indicator is diffusedly scattering or if a scattering foil is associated with this component or if the cover disc is designed so as to be diffusedly scattering. Furthermore, provision has been made according to the invention for the display indicators to be arranged so as to be displaceable in preferably at least one direction for the purpose of adjustment and/or for displaying multiple information at one point. If the quantity of light that is incident from the outside is insufficient for the illumination, then provision has been made for the arrangement of an optical component in front of the display indicator in such a way that an additional illumination can be directed into the regular reflection ray path.For this optical component, there may be used various forms of prisms, for example a cylindrical prism, a triangu lar prism, a Bauernfeind prism or other appropriately designed prisms giving multiple reflections. In order to create the most favourable illumination conditions for the reflection ray path, it is advantageous to arrange in front of the optical component for the additional illumination a compensation wedge component, which may be designed as a two-part pivoting or rotating wedge, so as to allow optimum illumination conditions to be set by means of a change of the wedge angle.

The invention will now be explained in more detail with the aid of some exemplified embodiments. In the accompanying drawings: Figure la shows a sectional representation of the viewfinder system with indicator reflection, Figure ib shows a front view of the cover hood, Figure ic shows the viewfinder image plane with the reflected indicator display, genuinely projected, Figures 2 and 3 show variants of the indicator arrangement, and Figures 4 and 5 shows variants of the indicator arrangement with additional illumination.

In Figure 1 a, there is shown the indicator reflection in conjunction with the viewfinder system. The display indicator 3 is illuminated by the outside light which, from the front in the shooting direction, first impinges on a reflecting prism 2. Due to the further light guidance in the interior of the cover hood 4 and of the camera, preferably at a short distance from and approximately parallel to the image erecting surface of the pentagonal prism 1, a space-saving arrangement is simultaneously brought about. A real projection of the display indicator 3 is effected in the viewfinder image plane (see Figure Ic) so that the reflection field is displayed in a trouble-free manner without any vignetting.

It emerges from Figure 2 that it is also possible for the reflecting prism 2 to be arranged downstream of the display indicator. The arrows in the individual figures illustrate which components can be moved in which direction for the adjustment and/or setting. As the indicators 3, there are preferably used LCDs which are also capable of providing coloured information if coloured filters or sheeting is inserted.

However, there may also be used conventional display means, such as symbol and scale plates, etc.

on film material, sheeting and other carriers in a negative and positive construction.

The optical component arranged upstream of the display indicator 3 may have a refracting effect; it may have a surface which is designed so as to be diffusedly scattering or with which a scattering sheet is associated. For example, the cover disc 5 (see Figure 3) may be diffusedly scattering.

If the quantity of light that is incident from the outside is not sufficient for the illumination, then provision is made according to the invention for supplementary lighting from a light source 7 arranged beneath the cover hood 4. These light sources may be miniature lamps, light-emitting diodes or other light-emitting elements. As is apparent from Figure 4, the light of the supplementary lighting passes through the transparent part of the display indicator 3, impinging on a cylindrical prism 6, and is directed by this prism into the regular reflection ray path. During this process, there occurs a twofold reflection on the cylindrical surface of the prism 6 and a single reflection on the plane surface thereof. Instead of a cylindrical prism 6, there may be used a triangular prism 8 (see Figure 5) or another suitable multiple reflection prism. In order to adapt the reflection ray path from the outside to the most favourable illumination conditions, it is expedient to arrange a compensation wedge component upstream of the optical component for the supplementary lighting. This component may be designed as a two-part pivoting or rotating wedge and, by changing the wedge angle, one can provide the respective optimum illumination conditions.

Claims

1. An arrangement of display indicators in the viewfinder system of reflex cameras, characterised in that the display indicator (3), in conjunction with at least one optical component, is arranged, directly in the shooting direction or directly behind the cover hood (4), at the top obliquely towards the front, and in that the reflection ray path extends approximately parallel to the image erecting surface of the pentagonal prism (1), there being effected in the further ray path a real projection of the display in the viewfinder image plane.

2. An arrangement of display indicators as claimed in Claim 1, characterised in that the optical component is a reflecting prism (2) which is arranged upstream or downstream of the display indicator (3) and allows the reflection ray path to be deflected parallel to the image erecting surface of the pentagonal prism (1).

3. An arrangement of display indicators as claimed in Claim 2, characterised in that one surface of the optical component arranged upstream of the display indicator (3) is diffusedly scattering or a scattering foil is associated with this component or the cover disc (5) is designed so as to be diffusedly scattering.

4. An arrangement of display indicators as claimed in Claim 1, characterised in that upstream of the indicator or the reflection component there is arranged a pivoting or rotating wedge pair.

5. An arrangement of display indicators as claimed in Claim 2, characterised in that as the display indicators (3) there are preferably provided LC displays which are displaceable in at least one direction.

6. An arrangement of display indicators as claimed in Claim 1, characterised in that an optical component is so arranged upstream of the display indicator (3) that supplementary lighting can be directed into the regular reflection ray path.

7. An arrangement of displayindicators as claimed in Claim 6, characterised in that the optical component is a cylindrical prism (6), a triangular prism (8) or another suitable prism.

8. An arrangement of display indicators as claimed in Claim 6, characterised in that there is provided in the regular reflection ray path upstream of the optical component for the suppiementary lighting a compensation wedge component which is designed as a two-part pivoting or rotating wedge.

9. An arrangement of display indicators for reflex cameras substantially as described with reference to any one of the examples shown in the accompanying drawings.