JPH0456933A - Camera with zooming photometric optical system - Google Patents

Abstract

PURPOSE:To obtain an inexpensive zooming photometric optical system by providing a zooming photometric optical system which varies a photometric range interlocking with the change of angle of view of a finder optical system and provided with an optical axis different from that of the finder optical system. CONSTITUTION:The zooming photometric optical system is provided at the same holding member separately from a zoom finder optical system, and the zooming of the photometric optical system is performed interlocking with the zooming operation of a zoom finder mechanically. In other words, when a gear 10a provided integrally receives the torque of a zoom driving mechanism 100 and is rotated, the zooming mechanism of a photographic lens in the inside of a rotary cylinder 10 is operated, which varies the focal distance of the photographic lens. At this time, since a zooming cam 9 is rotated integrally with the rotary cylinder 10, a second lens and a third lens are moved along the optical axis of a finder, and the finder optical system is zoomed interlocking with the change of the focal distance of the photographic lens. In such a way, cost down is realized by interlocking with a simple camera.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a zoom photometry optical system that performs zooming in conjunction with a zoom finder.

(Prior technology) In recent years, many compact cameras with built-in auto 7 focus lenses have built-in zoom lenses. The lens is inside! A camera has been proposed.

On the other hand, even in cameras with a built-in zoom lens, many cameras have conventionally used a fixed focus optical system for the measurement light optical system.
When the zoom ratio becomes 3x or more, if the photometric optical system has a fixed focus, it will move to the wide side as shown in Figure 1 (Figure 1 (a)).
The area of the Fuchikoen area on the (tele) side (Fig. 1 (b)) is 9
Since the value also changes by a factor of 1, it is not possible to accurately measure the light and give the appropriate exposure. Therefore, in recent years, cameras with built-in zoom photometry optical systems have been proposed.

(Problems to be Solved by the Invention) Figure 2 shows a zoom optical system of a photometer rrL (TTF-AE) using an objective lens optical system of a fine optical system. A second lens 202 that moves in conjunction with the lens 201 and a zoom drive system (not shown)
and zooming is performed by the third group 203. The AE optical system includes the Faing zoom optical system and the Porro prism 20.
A half mirror is attached to the fourth reflecting surface 204d of the Porro prism 204 in FIG.
The light is guided to the light receiving element 207 via.

With such a configuration, the photometry area can be zoomed by zooming the fine lens in conjunction with changes in the focal length of the photographic lens, and accurate photometry can be achieved. However, the Porro prism requires half-mirror processing and a photometric prism, making it expensive.

It is an object of the present invention to solve the above-mentioned problems and provide a low-cost zoom photometry optical system.

(Means for solving the problem) A zoom photometric optical system is provided on the same holding member separately from the zoom finder optical system, and the photometric optical system is zoomed by mechanically interlocking the zoom operation of the zoom finding device. I did it like that.

(Function) The present invention provides an inexpensive zoom photometry optical system by mechanically interlocking the zoom finding and zoom photometry optical systems. The zoom finding and zoom photometry optical systems are provided on the same base plate, and the photometry optical system driving cam is provided on the zoom finding driving member, thereby ensuring the positional accuracy of the finder optical system and the photometry optical system. This was designed to reduce costs by interlocking the two with a simple mechanism.

(Example) The present invention will be described in detail below with reference to the drawings.

- Finder optical system As shown in FIGS. 5 and 10, the objective lens has three columns, and the second lens 52 is fixed to the objective base plate 1. Second
The lens 52 has a bearing holding hole 52a outside the 7inder optical path in one body with the lens surface, and the bearing 2 is fixed in this hole after being pressed.
is fitted and held in the 7 under optical axis direction, and has a shaft 52b outside the pointing optical path in a direction perpendicular to the optical axis, and this pongee 52b is fitted with the guide 1!1a of the objective base plate 1. Then, the fine optical axis and its surrounding position are determined.

The third lens 53 is fixed to the lens holder 5,
In the lens holder 5, a bearing 5a provided in one body is fitted with a shaft 4 fixed to the objective base plate 1, and the lens holder 5 is held slidably in the optical axis direction. A shaft 5bfJtj' integrally provided on the holder 5 is fitted into a guide groove 1a provided on the mounting plate 1 to determine the position of the pointing and light transfer.

Next, the zooming operation will be described.

The second lens 52 is always biased toward the photographer side by a compression spring 19 fitted in lens 111+3, and is always biased toward the photography side by a zoom linkage shaft, and the zoom cam 9 is pushed by a zoom linkage shaft 52C. cam surface 9a of
(Fig. 4, Fig. 9).

On the other hand, in the tjIJ3 lens 53, the interlocking lever 6 is rotatably held on the objective base plate 1 by a rotating shaft 8 (FIG. 9), and engages with the protrusion 5C on the lens holder 5 to release the spring 7 (the ninth ) is urged toward the subject side, and is pressed against the cam surface 9b of the zoom cam 9 (FIGS. 4 and 9) by the zoom interlocking shaft 5d.

On the other hand, the zoom cam 9 rotates when the gear 10m provided in the zero-rotation barrel 10 fixed to the rotation barrel 10 (FIG. 4) receives the rotational force of the zoom drive system 100 (FIG. 4). , the zoom mechanism of the photographic lens (not shown) located inside the rotary barrel is activated to change the focal length of the photographic lens. At this time, since the zoom cam 9 rotates as one body with the rotating barrel, the second lens 52ttIIJ3 lens 53 moves along the pointing optical axis, and the pointing optical system zooms in conjunction with the change in focal length of the photographing lens. do. At this time, the zoom interlocking shafts 52d and 5d are directed toward the rotation center of the zoom cam 9, so that the rotational force of the rotary barrel is efficiently transmitted to drive the finder lens. As shown in FIG. 8, the eyepiece lens is composed of two lenses, and the sixth lens 56 has protrusions 5f3i and b in the direction perpendicular to the finder optical axis.
It is press-fitted into holes 11a and b provided in the eyepiece base plate 11 and held therein. The fifth lens 55 has protrusions 55 a, b, and e in a direction perpendicular to the finder optical axis, and the eyepiece base plate 1
It is positioned by fitting into m 11 cvdte on 1.

After the second reflecting mirror 58 is positioned by the protrusions 11g, h, and f provided around the opening of the eyepiece base plate 11, *i
It is fixed to the base plates 1,1. The first reflecting mirror 57 (FIG. 10) is also fixed to the eyepiece base plate 11 using a similar holding method. The condenser lens 56 has an optical design that has an image of the eyepiece optical system on the lens surface on the subject side.
A mark indicating the distance measurement range of the AF mechanism is made on the lens surface. Further, a field frame 12 having projections 56b, c and holes 12a, b that fit into the projections is positioned and fixed. After the field frame 12 is fixed, the condenser lens 56 is pressed against the surface 11j of the eyepiece base plate 11 and fixed. As shown in Figure 7,
The roof mirror 55 has a flat part 55b outside the reflective surface 55a, and after being positioned on the surface 11k of the sleeping board 11, the flat part 55c is pressed and held by the spring 12.

The eyepiece base plate 11 and the objective base plate 1 are each positioned and fixed to the side plate 13 to constitute a finder optical system.

Next, g adjustment of the distance measuring frame provided in the finder optical system will be explained.

As mentioned earlier, the distance measuring frame and the field frame are provided in one body on the condenser lens 50, but this measuring frame is located in the viewfinder field of view at a position facing the AF light receiving element (not shown). On the other hand, if the distance deviates significantly, it may cause erroneous distance measurements such as blank measurement. Therefore, in the present invention, the entire finder unit is movable, and the measurement button frame can be viewed from 1! lr! f! The configuration allows for

The configuration will be explained below.

As shown in FIG. 9, the finder unit is held in a front frame 41 so as to be rotatable about a rotation axis 1g on the objective base plate 1, and the rangefinder frame can be adjusted in the horizontal direction. After adjusting r+a, it is fixed to the front frame with screws through a hole provided in the bent portion 13m of the side plate 13. At this time, the rotation axis 1g is located approximately at the center of the movement range of the finder lens 52, 53. When the viewfinder (22) is rotated to adjust 11R, the zoom linking shaft 52c
.

Since the amount of engagement between 5d and the zoom cam 9 changes, this is to minimize the amount of change.

Finally, we will discuss the arrangement of the finder optical system.

In the finder optical system, the objective lens optical system is placed immediately next to the photographing lens, and then the roof mirror reflects the image diagonally upward toward the subject, forming an image on the rear surface of the condenser lens 55, and then transmitting the image through two anti-i* lenses. The photographer observes the image using the eyepiece optical system. This eliminates parallax in the vertical direction and shortens the overall length of the finder optical system, contributing to making the camera more compact.

- Photometric (AE) optical system Next, the AE optical system will be explained. As shown in FIGS. 5 and 8, the AE optical system is composed of two lenses, and the lens 61a is a condenser lens 6 for the AF auxiliary light.
11+, and is fixed to the objective base plate 2. The second lens 62 is fixed to the AE lens holder 21.

The AE lens holder has bearing parts 21a and 21b, and is guided by an id shaft 22, 23 fixed to the objective base plate 1.
It is movable only in the optical axis direction of the AE optical system. A
The E lens holder 21 has an interlocking pin 21e, which engages with the cam 6a of the interlocking lever b. As mentioned above, the third lens 53 of the 7-fin optical system is fixed to the lens holder 5 and moves back and forth along the finder optical axis in conjunction with the focal length of the main lens by rotation of the finder cam 9. However, at this time, since the protrusion 5C on the lens holder 5 is engaged with the interlocking lever 6, the interlocking lever 6 rotates in conjunction with the defocusing of the main lens.

Therefore, by forming the cam surface 6a in an appropriate shape, the focal length of the AE optical system can be linked to the focal length of the main lens for zooming.

The light receiving element 24 is fixed to a holder 25 and is held by being pressed against the GLC of the objective base plate by a spring 26, and is configured to be movable within a plane perpendicular to the optical axis of the AE optical system. This is ;l! in the photometric area. This is for the sake of alignment.

Next, we will discuss the adjustment of the measurement area.

As shown in Fig. 6, the light receiving element used in the AE of the present invention has two areas: a spot area that measures the center of the imaging range and an average area that measures the majority of the imaging range. Backlight detection is possible by measuring the difference in intensity in the average area, but in such systems, if the spot area deviates from the main subject intended by the photographer, this can cause malfunctions. On the other hand, when the focal separation of the AE optical system is shortened in order to make the AE optical system compact, the positional accuracy of each lens and light receiving element becomes very strict, and it is difficult to achieve this with component accuracy. Therefore, in the present invention, the spot area is adjusted by moving the light receiving element. As mentioned earlier, it is possible to adjust the viewing position of the AF light-receiving element in the 7-fin optical system.

On the other hand, since the AE optical system of the present invention is held by the same member as the finder optical system, there is no need for a special jig to align the viewing positions of the AE light receiving element and the AF light receiving element.
By aligning the focus position of the AE light receiving element with the distance measuring frame reference of the finder optical system, the looking position 2 of the AE light receiving element and the AF light receiving element can be adjusted.
It is possible to adjust the E direction rLv4, and it can be said to be useful for simplifying the range line.

- Auxiliary light optical system As shown in Figures 8 and 10, the auxiliary light lens Glb
is integrally molded with the AEN No. 1 lens 61a, and the objective base plate 1
is fixed. @Sukeko MLED31 is holder 32
The pattern mask 33 is also fixed to the holder 31.
is fixed.

The holder 31 is guided by gld, e, and f of the objective base plate 1, is pressed downward by a spring (not shown), and is slidable only in the optical axis direction of the auxiliary light lens 61m. The structure is such that the focus of the pattern mask 33 can be adjusted.

(Effects of the Invention) According to the present invention, as described above, the photometric optical system is linked by simply providing a drive cam on the member that drives the finder optical system, so the Porro prism is processed by half mirror processing. By forming one of the photometry lenses on the same member as the auxiliary light lens, and by holding the AE optical system with the finder base plate in one member, the number of parts can be reduced and costs can be reduced. There is.

Furthermore, by holding the photometric optical system in the same member as the finder base plate, it is possible to adjust the photometric area as a finder unit, simplifying the assembly process.
FIG. 3 is a sectional view showing a photometric optical system, and FIG. 3 is an enlarged top view of a Porro prism of a conventional TTF photometric optical system.

Fig. 4 to Fig. 11 show an embodiment of the present invention, Fig. 4 is a perspective view, Fig. 5 is a perspective view of the objective lens system and the AE second lens, and Fig. 6 is a perspective view of the photometric element. Figure 7 is a right side view, Figure 8 is a cross-sectional view of the finder photometry optical system, Figure 9 is a front sectional view of it, Figure 10 is a longitudinal cross-sectional view of the finder auxiliary light optical system during telephoto mode, FIG. 11 shows the longitudinal cross-section of each when wide.

Patent applicant: Minolta Camera Co., Ltd. Figure 1 is an explanatory diagram showing changes in the photometry area when zoomed. No. figure (a) WIDE M (b) At E position 21st! I No. figure No. figure No. figure

Claims (3)

[Claims] (1) In a camera having a zoom lens with a variable focal length and a zoom finder optical system whose angle of view changes according to the focal length of the zoom lens, the photometry range is adjusted in conjunction with the change in the angle of view of the finder optical system. A camera characterized by having a zoom photometry optical system having a different optical axis from a variable finder optical system. (2) The movable lens of the photometric optical system is moved by a drive member that moves the movable lens of the finder optical system. A camera according to claim 1. (3) The movable lens of the photometric optical system is provided with a cam on the drive member that moves the movable lens of the finder optical system,
3. The camera of claim 2, wherein the camera is moved along the cam.