JPH0210513Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a focus position adjustment device for a distance measurement sensor used in a TTL distance measurement device that detects a focused point by measuring light transmitted through a photographic lens with a distance measurement sensor. The present invention relates to a device for adjusting the optical path length of a ranging sensor.

For single-lens reflex cameras, TTL distance measuring devices have already been put into practical use that detect the in-focus point by measuring the light that passes through the photographic lens with a distance-measuring sensor. This TTL rangefinder uses a half mirror as the finder mirror, and the light that passes through this is incident on the rangefinder mirror, where it is reflected below the mirror box and guided to the rangefinder sensor. ing. This distance measurement sensor is
Various types have been proposed, one of which is the TCL module (manufactured by Honeywell, USA), which has a CCD line sensor placed behind the focal plane of the photographic lens. The distance measurement principle of this TCL module utilizes the phenomenon that the order of the light passing through the upper and lower halves of the photographic lens is reversed in front and behind the focal plane.

In the TTL distance measuring device described above, in order to perform accurate distance measurement, it is necessary to correctly position the distance measurement sensor on the focal plane of the photographing lens. For this reason, high processing precision was required for the mounting surface of the distance measuring sensor, and position adjustment was quite troublesome.

Based on the above background, it is an object of the present invention to provide a device that can easily adjust the optical path length of a distance measuring sensor.

The present invention is characterized in that a movable stage movable in the direction of the optical axis of the photographic lens is provided, and a distance measuring mirror and a distance measuring sensor are attached to this movable stage.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In FIGS. 1 and 2, light transmitted through a photographic lens 1 is reflected upward by a viewfinder mirror 2, passes through a focusing glass 3, a pentaprism 4, and an eyepiece 5 before entering the photographer's eyes. The finder mirror 2 is fixed to a mirror holder 7 supported on a shaft 6. This mirror holder 7 is biased counterclockwise, its tip is positioned by a rubber pin 8, and is normally inclined at 45 degrees with respect to the optical axis 9 of the photographic lens 1.

The finder mirror 2 is a half mirror, and the light transmitted therethrough passes through the opening 7a of the mirror holder 7 and enters the distance measuring mirror 11. This distance measuring mirror 11 is connected to the arm lever 1.
2 and reflects the incident light downward to enter the distance measuring sensor 13. The arm lever 12 is supported by a shaft 15 on a U-shaped moving table 14 . When shooting, arm lever 12
rotates clockwise around the shaft 15, retracts the distance measuring mirror 11, and moves the finder mirror 2 with a pin 16 provided on the arm lever 12.
is pushed up to block the finder optical path 10 as shown in FIG. The arm lever 12 is biased counterclockwise and remains stationary at a position where a portion thereof touches a rubber pin 17.

The viewfinder mirror 2 is mounted inside a mirror box 19. A movable table 14 is housed within this mirror box 19, and the two are connected via an adjustment screw 20, with a spring 21 interposed therebetween.

FIG. 3 shows the main part of the present invention. When the adjustment screw 20 is turned, the movable table 14 moves within the mirror box 19. When the moving table 14 moves forward by a distance a from the solid line position, the focal plane of the photographic lens 1 moves to position A. Conversely, when the moving table 14 is moved backward by a distance b, the focal plane of the photographic lens 1 moves to position B. By moving this moving table 14, adjustment can be made so that the light receiving surface of the distance measuring sensor 13 coincides with the focal plane.

In the present invention having the above configuration, a distance-measuring mirror and a distance-measuring sensor are attached to the movable base so that the movable base moves along the optical axis of the photographic lens, so that the position of the movable base can be adjusted. This makes it possible to easily adjust the optical path length of the ranging sensor. Furthermore, since the distance measurement mirror and the distance measurement sensor move together, the optical axis of the distance measurement sensor does not change before and after adjustment.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the present invention showing the viewfinder mirror in a lowered state, Fig. 2 is a sectional view showing the finder mirror in its raised state, and Fig. 3 is a main part of the invention showing the adjusted state. FIG. DESCRIPTION OF SYMBOLS 1...Photographing lens, 2...Finder mirror, 11...Distance measurement mirror, 13...Distance measurement sensor, 14...Movement base, 20...Adjustment screw, 21
……Spring.

Claims (1)

[Claims for Utility Model Registration] (1) Behind a finder mirror arranged at an angle of 45 degrees, a distance measuring mirror is arranged to reflect downward the light that has passed through the finder mirror. In a TTL distance measurement device in which light reflected by a distance mirror is incident on a distance measurement sensor, the distance measurement mirror and distance measurement sensor are attached to a movable base, and this movable base is aligned with the optical axis of the photographic lens. 1. An optical path length adjustment device for a distance measuring sensor, characterized in that it can move in a direction. (2) the moving table is placed on a mirror box;
The optical path length adjusting device for a distance measuring sensor according to claim 1, wherein both are coupled via an adjusting screw.