DE1215505B - Photographic viewfinder based on the Albada principle - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Inta .:

■ Number:
File number:
Registration date:
Display day:

G03b

German KL: 57 a - 9/01

1215 505
V22757IXa / 57a
July 7, 1962
April 28, 1966

The 'invention relates to a photographic viewfinder based on the Albada principle with in the viewfinder image appearing image field framing, with '· your a partially transparent spherical concave mirror through which the viewer see the objective to be sighted perceives a frame attached to a plane surface in the vicinity of the focal plane of the concave mirror imaged in a collimator-like manner approximately at infinity, in order to increase the contrast of the reflected frame compared to the. Finder field the flat frame support surface common to all frame parts optical axis of the viewfinder system is inclined in such a way that its upper edge is visible to the looking eye is too inclined, according to patent 1039 357 b.

In a modification of the embodiment of the Main patent drawn and described block shape with a translucent block made of glass or plastic between the viewfinder front element and the frame support can be one. Viewfinder, roughly off Reasons of simplification, cheaper and weight reduction, as is well known Create in such an "open" way that there is an air space in place of the connecting glass block occurs. In the latter case it is common to combine the individual viewfinder parts with a corresponding air gap in one To accommodate a common viewfinder housing, which is closed on the eye side by a pane of glass is. Occasionally the frame to be mirrored is applied to this glass pane so that it also serves as a frame support. However, disturbing light reflections often occur on this glass surface on, which are superimposed on the viewfinder image and caused by the aforementioned inclination of the Frame girder's improved contrast again, a disadvantage, especially in poor lighting can be significant.

The object of the invention is to remedy this disadvantage in a further development and an advantageous embodiment to reduce or reduce the subject matter protected in the main patent to a minimum that is no longer disruptive. to fix completely.

Using the measure known per se to avoid disruptive reflected light to arrange these slightly crooked on optically effective parts, while maintaining the initially mentioned inclination of the frame to be mirrored or its support for the purpose of increasing the contrast to solve the problem proposed according to the invention that the viewfinder housing to the eye to be closed opposite the viewfinder optical axis is inclined forward by about 2 to 10 ° upwards and consists of two

1 photographic viewfinder for the Albada
'■ - principle'., * "- '· - ' - - ■

Addition to patent: 1039 357 b -

Applicant:

Voigtländer Aktiengesellschaft, *

Braunschweig, Berliner Str. '53

. Named as inventor:
Dipl.-Phys. Friedrich Papke, Braunschweig

there is cemented to each other parts, the common flat cemented surface in a known manner carries to be mirrored frame and in the opposite direction as the disc containing them is inclined about 2 to 4 ° with respect to the optical viewfinder axis.

The invention will be explained in more detail using a drawn exemplary embodiment. In

Fig. 1 is a viewfinder according to the invention is shown schematically; in

F i g. 2 is the mode of operation of the embodiment according to FIG. 1 clarifies.

The viewfinder of FIG. 1 has as a front lens a non-refractive meniscus 1, on the looking in, held in the optical axis 2 eye 3 of the observer facing concave surface a partially transparent concave mirror 4 applied, for. B. is evaporated. The front lens 1 is in the housing 5 stored, in the example by inserting it into a recess 6 that acts as a receptacle, in which it is held by a subsequently inserted 'frame 7. The frame 20 to be mirrored is embedded in a manner known per se between two cemented glass surfaces. This is the putty area inclined by about 2 to 4 ° with respect to the optical axis, so that the upper frame part faces the eye is inclined. This measure has the effect that the frame is better illuminated and thus has a higher contrast appears in the image field. Opposite this frame inclination are the plane-parallel boundary surfaces of the plane-parallel frame support member created by cementing, inclined in the opposite direction, thus those occurring on these surfaces

609 560/281

Claims (1)

No reflections via the partially transparent hollow mirror through which the mirror 4 is directed into the eye. The inclination that the viewer perceives the object to be aimed at, this surface in relation to the optical axis in the opposite sense to the inclination of the picture frame in the vicinity of the focal plane of the concave mirror, is between 2 and 10 ° for a frame attached to a plane surface. In this way, without collimator-like, approximately at infinity, additional aids are obtained that are surprisingly reflex-free, with the aim of increasing the contrast of the mirrored-in Albada viewfinder. This cemented plate over the frame opposite the viewfinder field , so in this case both the task of the _Rahmenteile common flat frame support mirror carrier and the role of the inclined surface to the optical axis of the viewfinder system reflex deflecting cover plate. io obliquely, namely with its upper edge the In F i g. 2, the mode of operation of the embodiment-looking eye is too inclined, is shown schematically according to patent form according to FIG. 1. The partial 1039 357b, and in which the viewfinder components with transmissive concave mirror 4 is accommodated in a housing, for example from air distance, a light beam parallel to the optical axis 2, which penetrates on the eye side through a transparent 25, the plane-parallel pane _{on the inclined end plate 1S} is complete, since 23/24 stops. 'On both glass luff surfaces. The beam 26 reflected from the surface "24 |> viewer housing (5) to your eye (3)" or the target shooting from the surface 23 opposite the optically reflected remainder of the beam 25 still hits the viewer axis (2 ) 'throughout upi etj ^ a 2 .to IQ.? the concave mirror 4, the "from this" reflected beam _a o ciben naGjj rorjn. , is inclined and .this from zw, ei 27 and 27 a, however, there is certainly parts cemented to one another at the pupil, the parts of the observing eye 3 bypassing them. common .even putty surface (2J, -22) in an sjeji well-known frame to be mirrored Rate entitlement: ßffj , bears and those in the opposite direction Photographic viewfinder for the Albada- ₂₅ how dje "she containseao.de Spjieibe about 2 to Ä? principle with the image field appearing in the viewfinder image compared to the pp _iS tis, chen * ^ cher axis (2) frame, in which a partially permeable spher-, jst tends. 1 sheet of drawings 609 560/281 4.66 © Bundesdruckerei Berlin