JPS624694B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a single lens reflex camera using a penta structure such as a penta prism. This relates to an eye reflex camera.

When displaying photographic information within the viewfinder field of view, firstly, the photographic information must be easy to see.
Second, by introducing the light from the photographic information body into the viewfinder, it is possible to prevent the viewfinder system from becoming more compact, especially the penta structure.
It is necessary that there are no difficulties in manufacturing. 1st
In order to display information on the viewfinder in an easy-to-read manner, the distance from the eye to the viewable information image must be approximately the same as the viewfinder subject image, for ergonomic reasons to minimize eye fatigue even when viewed for long periods of time. It is said that it is best for the position of the information to be visible within the field of view below and outside the viewfinder screen. A known example of a single-lens reflex camera that forms a photographic information image below and outside the viewfinder screen within the viewfinder field of view will be described below.

In FIG. 1, 1 is an objective lens, 2 is a swing-up mirror, 3 is a focusing screen, 4 is a condenser lens, and 5 is a penta structure, and the drawing shows a penta prism. The pentagonal prism 5 has an entrance surface 5a on which light from the screen 3 enters, a roof surface 5b, a front reflective surface 5c, an output surface 5d, and a front non-reflective surface 5e. 6
is an eyepiece, and 7 is an observer's eye. Reference numeral 8 denotes a sub-prism fixed to the lower part of the entrance surface of the pentaprism 5. The light incident on the sub-prism from the information body 9 is reflected by the reflection surface 8a of this sub-prism, and is reflected from the entrance surface 5a of the pentaprism 5. The light enters the prism 5. The information light that has entered the pentaprism 5 is reflected by the roof surface 5b and the front reflective surface 5c, and then is emitted from the exit surface 5d of the pentaprism 5 in the direction of the eyepiece 6 and reaches the eye 7. At this time, in order to form an information image outside the finder screen at the bottom, the information light must be reflected outside the finder light beam reflection area of the front reflective surface 5c of the pentaprism. Therefore, the height of this pentaprism must be high enough to reflect the information light. In other words, when making the pentaprism smaller, at least an area for reflecting information light must be left below the front reflecting surface of the pentaprism.

FIG. 2 also shows a known example of a single-lens reflex camera in which it is impossible to make the pentaprism too small. 5f is an information light introduction surface created by specially cutting out the vicinity of the exit surface of the prism.
5g is a reflective surface provided opposite to the introduction surface 5f. The information light introduced from the introduction surface 5f is reflected by the reflection surface 5g, and then reflected by the reflection surface on the front side of the roof surface of the pentaprism, and is directed toward the eyepiece 6. In this single-lens reflex camera as well, the pentaprism cannot be made very small for the same reason as in the camera shown in FIG.

An object of the present invention is to provide a single-lens reflex camera that eliminates this drawback. This objective is achieved by configuring the information light beam to be reflected within the finder light beam reflection area of the front reflecting surface. In order to reflect the information light within the finder beam reflection area, the information light is introduced from the upper part of the exit surface of the pentaprism, reflected by the front reflecting surface, and taken out again from the upper part of the exit surface of the pentaprism, and this light is converted into the finder beam. This is done by passing the light across the eyepiece and guiding it into the eyepiece from below.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 shows a first embodiment of the invention. The light from the information carrier 9 enters into the pentaprism 5 from the exit surface 5b of the pentaprism 5, is reflected by the lower part of the phantom beam reflection area of the front reflecting surface 5c, and is emitted again from the upper part of the exit surface 5d. The information light emitted from the exit surface 5d is emitted from the exit surface 5.
A mirror 12 fixed at the upper part between d and the eyepiece 6 directs the light toward the lower part of the exit surface. 1
Reference numeral 3 denotes a mirror fixed to the lower part of the exit surface, and this mirror directs the information light from the mirror 12 to the lower part of the eyepiece. In this way, in this embodiment, since the information light is reflected in the flooder beam reflection area of the front reflection surface 5c of the pentaprism, there is no need to provide a special area for reflecting the information light on the front reflection surface 5c. It becomes possible to reduce the height of the pentaprism and thus make the camera more compact.

FIG. 4 shows a second embodiment of the invention. This second embodiment is characterized in that a plane-parallel plate is disposed between the exit surface of the pentaprism and the eyepiece, and the surface of this plane-parallel plate is used wisely.

14 is a parallel plane plate. The information light is introduced from the lower incident surface 14c of this plane-parallel plate, is internally reflected by the pentaprism-side surface 14a of the plane-parallel plate, and is further reflected by the upper reflection surface 14d.
After passing through the surface 14a, it is introduced into the prism 5. This information light takes the same optical path as shown in FIG.
The light passes through and enters the field. This light is reflected by the upper reflective surface 14d.
After being reflected by the lower reflecting surface 14e, the light is emitted from the eyepiece side exit surface 14b.

This parallel plane plate 14 can be modified in various ways as shown by number 15 in FIG. 5, number 16 in FIG. 6, number 17 in FIG. 7, and number 18 in FIG.

FIG. 9 shows a second embodiment of the invention. This embodiment can selectively display two types of information. One information carrier 9-1 is arranged near the upper inclined transmission surface 19d of the parallel plane plate 19, and the other information carrier 9-2 is arranged near the lower surface 19c. 20 is a mirror for information selection. This mirror 20 is movable along the inclined surface 19d. When the mirror 20 is in the state shown in the figure, the light from the information carrier 9-1 passes through the inclined transmission surface 19d, enters the pentaprism λ, is reflected by the front reflective surface 5c, and exits the pentaprism again. Injected parallel plane plate 1
After being reflected by the reflective surface 19f provided on the eyepiece side of the inclined surface 19d of No. 9 and the reflective surface 19e provided on the pentaprism side, the light is directed downward from the eyepiece. At this time, the light from the other information body 9-2 is transmitted through the inclined surface 19d and is not reflected in the direction of the pentaprism. When the mirror 20 is moved in the direction of the arrow, the light from one of the information carriers 9-1 is blocked by this mirror and does not go toward the prism 5. On the other hand, the light from the information carrier 19-2 is reflected by the front total reflection surface 19 and the mirror 20 and enters the prism 5. This light is reflected by the front reflective surface 5c, then reflected by the reflective surfaces 19f and 19e, and then heads toward the lower part of the eyepiece. FIG. 10 shows the footer field of view of FIG. 9, where 21 is the footer screen and 21-1 is an information image. By moving the mirror 20, this information image is changed into a display such as shutter seconds.

A third embodiment of the invention is shown in FIGS. 11, 12 and 13. In this embodiment, as shown in FIG. 13, two pieces of information can be displayed simultaneously on the outer lower part of the footer screen 23 within the field of view. Two information bodies 9
-1 and 9-2 are the same as in the second embodiment, but the information body 9-1 is placed in the front direction of the drawing, and the information body 9-2 is placed in the depth direction. As shown in FIG.
1 and a mirror surface 22d-2 are formed. Therefore, the light from the information carrier 9-1 can pass through the transmitting section 22d-1. Further, the light from the other information body 9-2 and the light from the information body 9-1 reflected by the prism front reflection surface can be reflected by the mirror surface 22d-2.

FIG. 14 shows a fourth embodiment of the invention. This embodiment uses a ghost cut prism instead of a parallel plane plate. 24 is a ghost cut prism, and 25 is an optical path correction prism. The light from the information body 9 is transmitted to the lower surface 2 of the prism 25.
5c and is directed toward the total reflection surface 24a of the ghost cut prism 24 by the total reflection surface 25b.
The light from the total reflection surface 24a is directed toward the front reflection surface 5c of the pentaprism 5 by the mirror surface 24d. The light from the reflective surface 5c passes through the reflective surface 24c and the total reflection surface 25.
b, reflected by the reflecting surfaces 25a and 25c and directed downward to the eyepiece 6. Incidentally, the ghost cut prism can be modified in various ways as shown by 26 and 27 in FIG.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams showing the viewfinder optical system of a conventional single-lens reflex camera, FIG. 3 is a diagram showing the first embodiment of the present invention, and FIGS. 4 to 8 are diagrams showing the first embodiment. FIG. 9 is a diagram showing a modified example of the parallel plane plate of the example, and FIG. 9 is a diagram showing a second embodiment of the present invention.
FIG. 0 is a diagram showing the funder field of view of the second embodiment, FIGS. 11 to 13 are diagrams showing the third embodiment of the present invention, FIG. 14 is a diagram showing the fourth embodiment of the present invention, and FIG. The figure shows a modification of the fourth embodiment. In the figure, 1 is an objective lens, 2 is a swing-up mirror, 3 is a focusing plate, 4 is a field lens, and 5
is a pentaprism, 6 is an eyepiece, 9 is an information carrier, and 12 and 13 are mirrors.

Claims (1)

[Claims] 1. In a single-lens reflex camera having a finder system for observing an object image formed in the vicinity of an entrance surface of the pentagonal structure through an eyepiece disposed on the exit surface side of the pentagonal structure, the pentagonal A parallel plane plate having first and second parallel planes that transmit the object image is provided between the structure and the eyepiece, and the parallel plane plate has a first transmitting section that transmits the first information and a second parallel plane that transmits the object image. a second transmitting section that transmits information from the first and second transmitting sections, and a second transmitting section that reflects light from the first and second information that has passed through the first and second transmitting sections and entered the pentagonal structure and is again introduced into the parallel plane plate. 1. The first transmitting section has a second reflective surface, and the first transmitting section further includes a reflective surface that reflects light from the second information, so that the first and second information can be displayed simultaneously. A single-lens reflex camera that is characterized by: