JPH0287132A - Finder display device - Google Patents

Abstract

PURPOSE:To allow a photographer to readily recognize an automatic focusing spot by using a hologram plate and displaying information on automatic focusing so as to overlap with an erect virtual image of an object that is focused automatically. CONSTITUTION:Plural light emitting elements 2A to 2E selectively emitting light to display the automatic focusing position are arranged outside a finder optical path. A hologram plate 3 arranged on the finder optical path diffracts the light from the light emitting elements and information on automatic focusing is displayed to overlap with the erect virtual image of the object that is automatically focused. Therefor, even if the virtual image of the object is formed ahead of the camera, hologram can surface the focused position display in the position where the virtual image is formed. Thus, an image of the object and the focused position display can be observed at the same diopter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a finder display device used in a multi-point autofocus camera equipped with a virtual image finder.

[Prior Art] Conventionally, multi-point autofocus cameras that can automatically adjust the focus at multiple locations on a photographic screen have been put into practical use. Such multi-point autofocus cameras can effectively adjust the autofocus even when the subject is outside the center of the shooting screen, but on the other hand, objects other than the intended subject may come into focus. There is also a drawback. Therefore, by adding a display means to the finder optical system, the visible change 1 at the focus point
It is necessary to wake up the enemy.

FIG. 5 shows the structure of a display device in a finder in a conventional single-lens reflex camera. Object light incident through the photographing lens 10 is reflected upward by the reflection mirror 11 and is focused on the focus plate 12 as a real image. A display plate 13 for displaying the in-focus point is placed over the focus plate 12.

The subject image on the focus plate 12 is converted into an erect image via the pentaprism 14 along with the in-focus point displayed on the display plate 13.
It is observed through the eyepiece lens 15.

Specific examples of the display board 13 include, for example, a method using a liquid crystal display board that can selectively display a plurality of display frames (Japanese Patent Application Laid-open No. 184235/1983), A method has been proposed in which one of the plurality of grooves is selectively illuminated by a light emitting element (Japanese Patent Laid-Open No. 17220/1983).

[Problems to be Solved by the Invention] Each of the above-mentioned conventional techniques can be easily implemented when a real image of the subject is formed inside the finder optical system, but it is difficult to implement the virtual image method in which a real image of the object is not formed inside the finder optical system. In a camera equipped with a viewfinder, it is difficult to arrange the display board so that it overlaps with the subject image.

On the other hand, Japanese Patent Publication No. 58-27504 discloses a technique that uses a hologram to match display information and the diopter of a monitor image, and Japanese Patent Application Publication Nos. 59-185319 and 60-23838 disclose , Japanese Patent Publication No. 60-60627
The publication discloses a technology for selectively displaying multiple field frames using multiple holograms and multiple reference beams, but none of these are technologies related to displaying the in-focus point in a multi-point automatic focusing camera. do not have.

In particular, in a multi-point autofocus camera equipped with a virtual image finder, the present invention enables the automatic focus adjustment point to be displayed superimposed on the virtual image of the subject, so that the photographer can easily understand the autofocus adjustment point. The object of the present invention is to provide a finder display device.

[Means for Solving the Problems] In the present invention, in order to solve the above problems, the first
As shown in the figure, a virtual image finder 1 for observing a virtual image of a subject formed by a lens system (objective lens IA)
A viewfinder display device for a multi-point autofocus camera, which is equipped with a viewfinder and is capable of selectively autofocusing multiple locations within the viewfinder's field of view, wherein the device selectively emits light to display the location where autofocusing is being performed. A plurality of light emitting elements 2A~
2E is placed outside the viewfinder optical path, and a hologram plate 3 displays information regarding automatic focus adjustment so that the light from the light emitting element is diffracted and superimposed on an erect virtual image of the subject during automatic focus adjustment.
is arranged in the finder optical path.

[Function] The present invention is a finder display device for a multi-point autofocus camera, which is equipped with a virtual image finder 1 for observing a virtual image of a subject formed by a lens system (objective lens IA). A real image is not formed, and it is difficult to display the in-focus point using a liquid crystal display panel or the like. Therefore, a plurality of light emitting elements 2A to 2E that selectively emit light so as to display the point where automatic focusing is being adjusted are arranged outside the viewfinder optical path, and the light from these light emitting elements is transmitted to a hologram plate placed in the viewfinder optical path. Display related to automatic focus adjustment is performed so as to be diffracted at step 3 and superimposed on the erect virtual image of the subject being automatically focused.In this way, even if a virtual image of the subject is formed in front of the camera, Since the in-focus point display can be highlighted by the hologram at the position where the virtual image is formed, the subject image and the in-focus point display can be observed at the same diopter.

[Example] FIG. 1 is a schematic TL diagram of an embodiment of the present invention.

The finder 1 of this embodiment is of an inverted Galilean type, and uses a concave lens for the objective lens IA and a convex lens for the eyepiece IB.The erect virtual image of the subject formed by the concave lens is enlarged by the convex lens to make it easier to see. . In this type of finder 1, an erect virtual image of the subject is formed closer to the subject than the objective lens IA. Therefore, if an attempt is made to place the display board at the same position as the erect virtual image of the subject, the display board will be located in front of the camera, making it virtually impossible to arrange the display board.

Therefore, in the present invention, a reflective diffraction type hologram plate 3 is placed immediately after the objective lens IA in the finder optical path, so that the in-focus point display image appears ahead of the objective lens IA.

Numerals 2A to 2E are light emitting elements arranged outside the finder optical path, and one of them selectively emits light to irradiate the hologram plate 3 in the finder optical path. These light emitting elements 2A to 2E are usually made of semiconductor lasers that generate coherent light, but the hologram plate 3
Depending on the type of light emitting diode that generates non-coherent light, it is also possible to use a light emitting diode. When the hologram plate 3 reflects the light from the light emitting elements 2A to 2E, it diffracts a part of the reflected light toward the eyepiece lens IB, thereby making an image representing the in-focus point appear ahead of the objective lens IA. Also,
Light from objective lens IA passes through without obstruction. Therefore, from the eyepiece IB, the royal virtual image of the subject formed by the objective lens IA and the in-focus point display image formed by the reflected and diffracted light from the hologram plate 3 are observed in a superimposed manner.

Furthermore, since the diopters of the erect virtual image of the subject and the in-focus point display image are approximately the same, the display is easy to see and is resistant to mouth movements.

FIG. 2 shows a display example of the finder display device of this embodiment. A subject image 4 is formed as a virtual image within the field of view of the finder. 5A to 5E are in-focus point display images by the light emitting elements 2A to 2E, respectively. In the example shown in FIG. 2, since the light emitting element 2B is emitting light, the focused point display image 5B appears superimposed on the subject image 4, and the other focused point display images 5A and 5C to 5E appear. Not yet.

FIG. 3 is an explanatory diagram of the operation of the hologram plate 3 used in this embodiment. Interference fringes 3A are provided on the surface of the hologram plate 3.0 When the reproduction light from the light emitting element 4 is irradiated onto the interference fringes 3A, a part of the transmitted light is diffracted and becomes reproduction light as transmitted diffraction light. . In this case, interference fringes 3 on the hologram plate 3
Since the pitch of A is different, the diffraction angle of the transmitted diffracted light is different, and the hologram plate 3 acts like a convex lens.On the other hand, a part of the reflected light is diffracted and becomes reproduced light as reflected diffracted light. In this case, since the pitch of the interference fringes 3A of the hologram plate 3 is different, the diffraction angle of the reflected diffracted light is different, and the hologram plate 3 has a concave mirror effect.In the embodiment shown in FIG. A reflection hologram is used for reproduction.

The hologram plate 3 in the above embodiment is arranged so that the light emitting elements 2A to 2E located outside the viewfinder optical path can be seen without distortion in the viewfinder field of view due to its concave mirror action, and so as not to affect the subject light within the viewfinder field of view. has been done.

FIG. 4 is a schematic diagram of a distance measuring device used in a multi-point autofocus camera. This distance measuring device measures the distance to a subject using a triangular distance measuring method that includes a light projecting optical system and a light receiving optical system. The light projection optical system includes a light projection lens 6 and a plurality of light emitting elements 7a to 7 arranged in a row perpendicular to the optical axis of the light projection lens 6.
Contains e.

The light-receiving optical system includes a light-receiving lens 8 and a plurality of light-receiving elements 9a-9r arranged perpendicularly to its optical axis.The light-emitting elements 7a-7e emit light in the infrared wavelength range, for example. The light receiving element 9a consists of a light emitting diode that emits
9r is composed of a silicon photodiode that is sensitive to light in the infrared wavelength range, for example. The arrangement direction of each lens 6.8 and each element 7a to 7e.

The arrangement direction of 9a to 9r is parallel to the horizontal direction of the photographing screen, and the subject distance is measured at multiple points along the horizontal direction of the photographing screen so as to correspond to the in-focus point display images 5A to 5E in FIG. It can be measured. A plurality of light emitting elements 7a
~7e sequentially emit infrared light, and the infrared light reflected by the subject is received by any of the light receiving elements 9a~9r,
The distance of the subject in the far and near direction and the position in the left and right direction are detected.

For example, if a subject exists at the position indicated by B in FIG. 4, the photographic lens is driven to focus on the subject distance measured by the distance measuring device.

When the lens driving is completed, the light emitting element 2B (see Fig. 1) emits light to indicate that it is in focus, and as shown in Fig. 2, an in-focus point display image is displayed at the in-focus point on the photographing screen. 5B appears. This allows the observer to know that the subject image 4 with the in-focus point displayed is in focus.

It goes without saying that the present invention is applicable not only to an inverted Galilean type finder but also to any autofocus camera equipped with a type of finder that observes virtual images.

In addition, although a reflective hologram plate is used in the embodiment, a transmissive hologram plate is placed just in front of the eyepiece.
The front surface of the hologram plate may be illuminated with a light emitting element, and the focused point may be displayed using transmitted diffracted light.

[Effects of the Invention] According to the present invention, in a multi-point autofocus camera equipped with a virtual image finder, a hologram board is used to display a display related to autofocus adjustment so as to be superimposed on an erect virtual image of a subject during autofocus adjustment. As a result, even in cameras where a real image of the subject is not formed inside the viewfinder optical system, the display related to automatic focus adjustment can be displayed so as to be superimposed on the subject being automatically focused within the viewfinder field of view. be.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, FIG. 2 is a diagram showing a display example of the same, FIG. 3 is an explanatory diagram of the operation of a hologram plate used in the same, and FIG. 4 is a multi-point diagram used in the same. A schematic configuration diagram of an optical system for automatic focus adjustment, FIG. 5 is a schematic configuration diagram of a conventional example. 1 is a virtual image finder, 2A to 2E are light emitting elements, and 3 is a hologram plate. r--4-1- 2A-2E-Light emitting element 3--Hologram plate

Claims (1)

[Claims] (1) A finder display device for a multi-point autofocus camera that is equipped with a virtual image finder that observes a virtual image of a subject formed by a lens system, and that is capable of selectively autofocusing multiple points within the viewfinder's field of view. A plurality of light-emitting elements that selectively emit light so as to display the point during automatic focus adjustment are arranged outside the viewfinder optical path, and the light from the light-emitting elements is diffracted to create an erect virtual image of the subject during automatic focus adjustment. 1. A finder display device comprising a hologram plate arranged in a finder optical path for displaying information regarding automatic focus adjustment so as to be superimposed on the image.