JPH0246434A - Image pickup device - Google Patents

Abstract

PURPOSE:To precisely and readily adjust the positions of a focusing screen and an image pickup element and to manufacture an image pickup device at a low cost by movably supporting an image pickup optical system and a finder optical system along an identical guide axis. CONSTITUTION:The image pickup optical system 2 which is fixed in the holding frame body of a camera main body and is composed of groups of zoom lenses 3, 4 and 5 is movably supported by a pair of guide axes 18a and 18b in the optical axis direction of a group of relay lenses 6. Then the pair of the guide axes are extended. Through the use of focusing screen fixing frames 15 and 16, fixing arms 8a and 8b and supporting arms 12a and 12b, a beam splitter 7, the focusing screen 10, a half mirror 11 and such members relating with the finder optical system 9 as the image pickup element 8 and an eyepiece lens 12 are disposed on the pair of the guide axes 18a and 18b in the way that they are readily and minutely adjustable. Therefore, adjusting and assembling the image pickup device 1 is highly efficiently performed and the device can be manufactured at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imaging device, and more particularly, to a support structure for lenses, mirrors, etc. of an imaging optical system and a finder optical system in an imaging device such as an electronic camera.

[Prior Art] As is well known, in imaging devices such as video cameras and electronic cameras, the imaging optical system includes a zoom optical system in addition to a focusing optical system. Furthermore, since the object light transmitted through the imaging optical system is guided onto the image sensor and to the finder optical system, these must be placed in positions that are accurately related to the imaging optical system. , their structures are becoming increasingly complex and expensive.

The arrangement of the optical system of this imaging device is, for example, approximately similar to the arrangement of the optical system of a single-lens reflex camera that uses silver halide film. A beam splitter for splitting the finder optical path is arranged in the imaging optical system in front of the camera, and a focusing screen is arranged above the splitter at an optical position conjugate with the image sensor. A half mirror is arranged, and the finder eyepiece is arranged on the optical path reflected backward by the half mirror. The imaging optical system is composed of a zoom optical system including a focusing lens group, and the light transmitted through the finder half mirror is received by a photometric sensor.

In the arrangement of such an optical system, the focusing screen must be placed accurately in a position that is optically conjugate with the imaging element surface with respect to the photographing lens, so the position of the focusing screen must be adjusted with a washer or a Adjustments are made using spacers.

However, this adjustment means not only requires a lot of time and effort, but also requires preparing and managing a large number of parts while assembling and adjusting them.

Therefore, in order to reduce the number of adjustment means, in the imaging device described in Japanese Patent Publication No. 62-44466, each component of the imaging optical system and the finder optical system is separated from the left and right by a support frame that is divided into two parts. They are clamped and held together, which simplifies assembly and adjustment while guaranteeing the accuracy of the camera.

[Problem to be solved by the invention] However, at first glance, the assembly method described in Japanese Patent Publication No. 62-44466 seems to guarantee assembly accuracy, but it depends on the molding accuracy of the frame, and the optical system Since there is no reference for the direction of the optical axis, a separate reference part is required, which may make the adjustment more complicated.

SUMMARY OF THE INVENTION Therefore, the purpose of the present invention is to solve the two problems, uniquely determine the reference for the optical axis direction of the optical system, reduce assembly and adjustment man-hours to a large rIJ, and extremely reduce the number of parts used. An object of the present invention is to provide an imaging device that can be manufactured at low cost.

[Means for Solving the Problems and Effects] The imaging device according to the present invention is characterized in that an imaging optical system and a finder optical system are supported movably along the same guide axis.

[Example] The present invention will be specifically described below with reference to the drawings. 1st
The figure is a perspective view of an imaging device showing an embodiment of the present invention.

This imaging device] has an imaging optical system 2. Noahinter optical system 9
．． The main part thereof is composed of the image sensor 8 and the same guide shafts 18a and 1.8b that support the image sensor 8 so as to be movable in the optical axis direction. The imaging optical system 2 includes a focusing lens group 3. Varieta lens group 4. Convensatorence group 5. The zoom lens group is composed of four lance groups of the relay lens group 6, and at the rear position of the upstream relay lens group 6 on the optical axis 0 of the imaging optical system 2, COD and M
An image sensor 8 composed of an OS, etc. is arranged, and a beam splitter 7 is arranged in front of it on the optical axis O, which splits a part of the imaging optical path upward and guides it to the finder optical system. . The beam splitter 7 is formed of a semi-transparent prism, and above it, a focusing screen]-0 is disposed at a position optically conjugate with the imaging surface of the image sensor 8.

The finder optical system 9 is refracted backward by the focusing screen 10, a half mirror which is installed obliquely above the screen 10 and horizontally reflects the finder optical path backward, and the mirror 11. +1lIf is formed with the eyepiece lens 12 disposed on the finder optical path 01, and the eyepiece lens 12 passes through the half mirror 11 to the focusing screen 10.
The object light image formed above is observed.

Further, above the half mirror 1 of the finder optical system constructed in this manner, a photometric sensor 4 is arranged via a photometric lens 13, as shown in FIG. In the center of this photometric sensor 4, a photometric light receiving section 1.4a formed of, for example, a hybrid IC or the like is disposed.

Returning to FIG. 1, the optical system and image sensor configured in this way are connected to a pair of guide shafts 18a and 18a attached to a holding frame 2 which is integrally fixed to the immovable part of the camera body.
], 8b is supported as follows. That is, the holding frame 21 has a pair of U-shaped frames 21 facing each other.
a 21b and a semicircular connecting frame 21c that connects the front parts of both frame bodies, and is fixed approximately in the center of the camera body so as to penetrate from the front to the rear. Both ends of a pair of round bar-shaped guide shafts 18a and 18b are respectively fixed to the front and rear bent ends of the pair of frames 21a and 21b.
a, 18b are parallel to each other, and the above-mentioned frames 21a, 2
], b are arranged and fixed so as to be parallel to each other.

The pair of guide shafts 18a18b arranged in this way are
For the imaging optical system 2, it serves as a guide rail for moving the lens group and as a mounting member, and for the finder optical system 9 and the image sensor 8, it serves as a mounting member whose mounting position can be adjusted. That is, support arms 3a, 3b, 4a, 4b, 5a.

5b extends left and right, and by tightly fitting the tips of these arms to the pair of guide shafts 18a and 18b, each lens group 3, 4°5 is accurately aligned on the optical axis 0. Each of these lens groups 3, 4.5 is moved back and forth by a lens drive mechanism (not shown). Further, after the lens frame holding the relay lens group 6 has the support arms 6, a, and 6b extending from the left and right centers thereof fitted into the pair of guide shafts 18a and 18b at their middle portions,
Each tip end is integrally fixed to the pair of frames 21a and 21b, and the relay lens group 6 is arranged on the optical axis O.

On the other hand, the imaging device 8 disposed behind the imaging optical system 2 thus disposed also has mounting arms 8a extending from opposite left and right sides of its holding frame.

8b, the imaging surface is aligned with the optical axis O by tightly fitting each tip portion into the pair of guide shafts 18a18b.
is placed on top.

The beam splitter 7 disposed in front of the image sensor 8 and behind the relay lens group 6 includes a focusing screen 10 disposed above it, and a half mirror disposed above it. 11 and this mirror 1], a photometric lens 13. As shown in FIG. 2, the photometric sensor 14 and the photometric sensor 14 are integrally arranged by focusing screen mounting frames 15 and 16. That is, the mounting frames 15 and 16 are formed as cubes that stand vertically on the optical axis O,
The cube is made up of split molds that are roughly symmetrically divided into left and right sides. On the opposing inner surfaces of the two split molds, from below to above, there is a concave portion 17 for accommodating the beam splitter 7, a four section 19 for accommodating the focusing screen 10, and a four section 20 for accommodating the half mirror 11.
．． A recessed portion 23 for housing the al11 optical lens 13. In order to accommodate the photometric sensor 14 in the four parts 24, each recess is vertically connected and bored so as to strictly regulate the arrangement dimensions of each optical member and accommodate half of each optical member. . Openings 15a and 16a for incident light are formed in front of the four parts 17 that house the beam splitter 7 located on the optical axis O, and openings 15a and 16a for incident light are formed at the rear in the vertical communication passages below the four half mirror housing parts 20. Output light openings 15b, 1
6b are arranged in series. In addition, the focusing screen 15.16 in which the optical member storage recesses 17, 19.20, 23.24 are formed on the opposing inner surface in this way,
A coupling protrusion 15c, 1 is provided on the inner surface of one of the fitting parts 15.
5d, and these coupling protrusions 15c and L5d are tightly fitted into the four coupling parts (not shown) formed on the inner surface of the other mounting member 16, so that the two mounting parts shrines 1516 are combined. and become one. Mounting protrusions 15e and 16e are provided at lower positions on each of the left and right outer peripheral surfaces of the members 15 and 16 configured in this way. By tightly fitting the drilled through holes in the optical axis direction to the pair of guide shafts 18a and 18b, the focusing screen mounting members 15 and 16 are installed between the relay lens group 6 and the image pickup device 8. It is arranged in an upright state.In this arrangement position, the incident light opening 15a is placed on the optical axis O.
.

16a is located, and this opening 15
A part of the subject light incident from a+ 16 a is reflected upward by the beam splitter 7 disposed within the recess 17, and this reflected light forms an image on the focusing screen 1o disposed within the fourth section 19. . Further, this image formation state is observed through an eyepiece lens 12 through a half mirror 11 disposed above it, and the light reflected upward by the beam splitter 7 passes through a focusing screen 10. It is bent horizontally backward by the half mirror 11, passes through the exit light openings 15b and 16b,
A finder optical path is formed to emit the light to the outside of the shrines 15 and 16. The eyepiece lens 12 is disposed at a position facing the emitted light openings 15b and 16b of the mounting member 15, 16.

That is, this eyepiece 12 has inverted-shaped support arms 1.2a and 12b integrally provided on the left and right sides of the lens frame holding the eyepiece, respectively, and the lower ends of each of the arms 12a and 12b. portion is the pair of guide shafts 18a.
, 18b, and is disposed on the finder optical path.

As described above, the configuration of the imaging device 1 according to the present invention includes a pair of guide shafts 1 that support the imaging optical system 2 movably in the optical axis direction.
8a, 131) and attach the focusing screen (=I frame 15, 16, image sensor mounting arm 8a,
8b and eyepiece support] ] Arms 12a, 1.2b support beam splitter 7.
, Focusing screen] 0 Half mirror 1, 1
and image sensor 8. Since the parts related to the finder optical system 9, such as the eyepiece lens 2, etc., are arranged in a manner that allows for easy and fine adjustment, mj assembly can be done very efficiently.

Moreover, FIGS. 3(A) and 3(B) show a side view and a front view of the optical system in the imaging device according to this embodiment,
As can be seen from this figure, in the present invention, two guide shafts 18a disposed on both sides of the focusing lens group 3,
Since all component shrines are supported by 18b, the space for placing mechanical parts and electrical parts is limited in the vertical direction.
Especially the lower part is very empty. Also, compared to the focusing lens group 3, the variator lens group 4. Compensator lens group 5. Since the relay lens group 6 is composed of a lens group with a small diameter, the relay lens group 6 avoids the focusing lens group 3 and covers a very long range parallel to the tunoids 18a and 18b from the rear lower part thereof, for example, a large printed wiring board 2.
5 can be placed close to the optical axis. In this way, by arranging a large printed wiring board parallel to the guide rail, the mounting density can be improved. In the case of the figure, the large printed wiring board 25 is connected to an electric circuit board 26 for the imaging cable 8 by a flexible printed circuit board 27 for use.

In this embodiment configured as described above, fine adjustments to accurately obtain the subject image on the focusing screen 10 are made using the focusing screen mounting frame shown in FIG. 8a and 18b in the front-rear direction, the optical path length up to the focusing screen 10 changes, so that the focusing screen 10 can be placed at a position optically conjugate with the image sensor 8. Therefore, the same subject image as that obtained on the image sensor 8 can be obtained on the focusing screen 10.

The photographer can check with his or her own eyes whether the object image thus obtained on the focusing screen 10 is in focus using the finder optical system 9. Further, this in-focus state is also displayed by the in-focus display LED 12c disposed within the finder lens frame. Also,
The eyepiece 12 has its support arm 12'a 12
By moving b along the guide shafts 18a and 18b and displacing it in the optical axis direction, the diopter of the finder can be adjusted.

Also, the focusing operation is usually performed by moving the focusing lens group 3 in the optical axis direction, or by moving the focusing lens group 3 in the optical axis direction, or by moving the focusing lens group 3 in the optical axis direction.
Alternatively, this can be done by moving the image sensor 8 in the optical axis direction.

[Effects of the Invention] As described above, according to the present invention, since the imaging optical system and the finder optical system are movably supported along the same guide axis, the positions of the focusing screen and the imaging device can be adjusted accurately. , it can be easily carried out, and the remarkable effect that the imaging device can be manufactured at low cost is exhibited.

[Brief explanation of the drawing]

1 is a perspective view of an imaging device showing an embodiment of the present invention; FIG. 2 is an exploded perspective view showing the mounting arrangement structure of the finder optical system in FIG. 1; FIG. 3(A); (B) is a side view and a front view showing the arrangement of the optical section II in the imaging device shown in FIGS. 1 and 2 above. 1......Imaging device 2...
......Imaging optical system 8...
...Image sensor 9...Finder optical system 18a, 18b...Guide shaft

Claims (1)

[Claims] (1) An imaging device characterized in that an imaging optical system and a finder optical system are supported movably along the same guide axis.