JP2001215569A - Optical finder device, photographing lens unit and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the length (axial length of a cam ring, etc.), of a mechanism for a finder longer by as much as a collapsible area cam as this collapsible area cam is disposed by avoiding a zoom area cam, when a cam mechanism for the finder is continuously provided with the zoom area cam and the collapsible area cam. SOLUTION: This optical finder device has a cam member 34, rotating cooperatively with the operation in the zoom region and housing region of a photographing lens and is formed with the plural zoom area cam sections 34a and 34b1, which are respectively engaged with plural finder lenses 22 and 23 and drive the respective finder lenses to zoom, by accompanying the zoom operation of the photographing lens. Both ends of at least one (34a) among these plural zoom area cam sections are made continuous in the rotating direction of the cam members. The finder lenses are engaged with both the zoom area cam sections, when the photographing lens exists at the zoom region, and when the photographing lens exists at the housing region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical finder device used for a camera, a video camera, a digital still camera and the like.

[0002]

2. Description of the Related Art A photographing zoom lens has a plurality of movable lenses for zooming (variable magnification). These movable lenses are moved in the optical axis direction by a cam mechanism (cam ring or the like) for the photographing zoom lens. The position is adjusted.

An optical zoom finder device arranged around a photographing zoom lens also has a plurality of movable lenses for zooming (variable magnification). These movable lenses are provided with a cam mechanism (camera) for a finder. The position is adjusted in the optical axis direction by a gear train or the like so as to interlock with the zoom operation of the photographing zoom lens.

Here, in the case of a so-called collapsible zoom lens in which the mechanical length is shortened (stored) when the photographing zoom lens is not photographed, the cam mechanism for the photographing zoom lens includes:
A cam in the zoom area and a cam in the collapsed area are provided continuously.

Since the cam mechanism for the photographing zoom lens and the cam mechanism for the finder are linked by a gear train or the like, the cam mechanism for the finder also has a cam in the zoom area and a cam in the collapsible area. Must be provided.

[0006]

However, in a cam mechanism for a finder, when a cam in a zoom region and a cam in a collapsed region are continuously provided, it is necessary to provide the cam in the collapsed region avoiding the cam in the zoom region. The length of the cam mechanism for the viewfinder (the axial length of the cam ring etc.)
This leads to a problem that the size of the finder device becomes longer, which leads to an increase in the size of the entire finder device.

FIG. 5 shows a cam cylinder used in a conventional finder cam mechanism, which is developed in a circumferential direction. The cam barrel 134 has a first zoom area cam groove (a1 to a3 portion) 134a1 for driving the first finder zoom lens and a second zoom area cam groove (for driving the second finder zoom lens). b1 to b3)
134b1 is formed over substantially the entire circumference of the cam cylinder 134. In the cam barrel 134, a first collapsible area cam groove (shaded portions a3 to a5) 134a2 that engages with the first finder variable power lens when the photographing lens is in the collapsible area is provided in the first zoom area. A first collapsible area cam groove (b3 to b5) 134b formed continuously with one end of the cam groove 134a1 and also engaged with the second finder variable magnification lens when the photographing lens is in the collapsible area.
2 is formed continuously with one end of the second zoom area cam groove 134b1.

As can be seen from this figure, the first retractable area cam groove 134a2 is different from the first zoom area cam groove 134a1 and the second zoom area cam groove 134a1.
Since the second zoom area cam groove 134b1 extends between the first zoom area cam groove 13b1
4a1 must be provided in the axial direction of the cam cylinder 134. As a result, the axial length of the cam cylinder 134 increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a compact optical viewfinder apparatus for a retractable photographing lens, in which the cam mechanism of the viewfinder is made smaller, the unity of the viewfinder apparatus as a whole is good.

[0010]

In order to achieve the above object, the present invention has a cam member which rotates in conjunction with the operation of a taking lens in a zoom region and a storage region. An optical finder device formed with a plurality of zoom area cam portions that engage with each of the finder lenses and drive each of the plurality of finder lenses in accordance with the zoom operation of the photographing lens.
At least one of both ends of the plurality of zoom area cam portions is continuous in the rotation direction of the cam member, and the zoom area cam portion has a viewfinder both when the photographing lens is in the zoom area and when it is in the storage area. The lens is engaged.

[0011] This makes it possible to provide another zoom area cam section closer to the zoom area cam section having both ends continuous in the axial direction of the cam member, thereby reducing the axial length of the cam member. Thus, it is possible to reduce the size of the entire finder device.

If the zoom area cam having both ends continuous and the storage area cam section with which the finder lens is engaged when the taking lens is in the storage area have a continuous zoom area cam section, the cam can be provided. It is possible to easily secure the required zoom performance of the finder optical system while reducing the size of the members.

[0013]

FIG. 4 shows a taking lens unit according to an embodiment of the present invention. In this photographing lens unit, a photographing zoom lens unit A and an optical zoom finder (OVF) unit B are integrally combined to form a unit. The taking lens unit is attached to a camera body (not shown).

In the photographing zoom lens section A, reference numeral 1 denotes a photographing zoom lens main body, reference numeral 3 denotes a first-group barrel which is retractable with respect to the photographing zoom lens body 1, and reference numeral 4 denotes a photographing held by the first-group barrel 3. This is the front lens of the lens. Reference numeral 5 denotes a main body cam gear for transmitting the operation of the photographing zoom lens unit A to the optical zoom finder unit B.

The first lens barrel 3 is retracted to the position shown by the solid line when not photographing, and is retracted (stored) with respect to the photographing zoom lens body 1. When photographing, it protrudes to the position 3 '(dotted line).

In the photographing zoom lens unit A, a plurality of variable power lenses (not shown) inside are driven by a lens barrel cam mechanism (not shown), thereby performing a zoom operation of the photographing lens. As a driving source (not shown) for this zoom operation, a step motor or the like housed inside the lens barrel is used to reduce the size of the photographing zoom lens unit A.
The driving force from the driving source drives the lens barrel cam mechanism via the gear train. The main body cam gear 5 is one of the gear trains.
One.

Next, referring to FIG. 1 and FIG.
The part B will be described. FIG. 1 shows a front view (A) of the OVF section B and a plan view (B) showing the OVF section B with the cover member removed, and FIG. 2 shows a rear view of the OVF section B. (A) and a side cross section of the OVF portion B (FIG. 1 (A)
(B-) of FIG.

Reference numeral 31 denotes an OVF base member fixed to the photographing zoom lens unit A, and reference numeral 21 denotes an OVF objective lens held at the front end of the OVF base member 31. 2
Reference numerals 2 and 23 respectively denote an OVF first variable power lens and an OVF second variable power held by first and second moving frames 22 a and 23 a guided in the optical axis direction by a guide bar 33 in the OVF base member 31. It is a lens (a finder lens referred to in the claims). Reference numeral 28 denotes an OVF eyepiece window held at the rear end of the OVF base member 31.

Reference numeral 34 denotes an OVF cam cylinder (a cam member referred to in the claims).
The OVF cam gear 35 is provided integrally. Also,
37 is a diopter adjustment dial.

In the photographing lens unit configured as described above, when the lens barrel cam mechanism in the photographing zoom lens unit A is driven and the photographing zoom lens unit A performs a zoom operation,
OVF cam gear 35 meshing with main body cam gear 5
, And the OVF cam cylinder 34 is rotationally driven.

A first cam groove 34a and a second cam groove 34b, which will be described later, are formed on the outer periphery of the OVF cam cylinder 34, and cam followers 22b and 23b (FIG. 3) which engage with these cam grooves 34a and 34b, respectively. The first and second moving frames 22a and 23a (that is, the first
OVF variable power lens 22 and second OVF variable power lens 2
3) Zoom drive.

The first cam groove 34a and the second cam groove 34b formed on the outer periphery of the OVF cam cylinder 34
F first variable power lens 22 and second OVF variable power lens 23
Is formed so that the zoom state between the telephoto end and the wide end is always the same as the zoom state between the telephoto end and the wide end of the photographing zoom lens unit A.

As shown in FIG. 4, when the photographing zoom lens unit A is shortened to the wide end, the vertical view angle of the OVF unit B is in the V range, and the horizontal view angle is in the H range. However, between the V range of the angle of view in the vertical direction and the first-group barrel 3 ′ in the wide-angle shortened state, the first-group barrel 3 ′ can be seen by the photographer looking through the OVF section B. A certain clearance must be provided so that there is no clearance.

Therefore, the distance D between the optical axes between the front lens 4 of the photographing lens and the OVF objective lens 21, which determines the positional relationship between the photographing zoom lens unit A and the OVF unit B, is made smaller than the value for ensuring the clearance. Can not do. Therefore, a certain amount of space is generated between the photographing zoom lens unit A and the OVF unit B.

Therefore, in this embodiment, the main body cam gear 5, the OVF cam cylinder 34 and the OVF cam gear 3
5, thereby effectively utilizing the space, which is essentially a dead space, to make the taking lens unit compact and cohesive.

Next, the shape and arrangement of the cam grooves in the OVF cam cylinder 34 will be described with reference to FIG. FIG.
FIG. 5 is a diagram in which the OVF cam cylinder 34 is developed twice in the circumferential direction.

When the zoom lens unit A performs a zoom operation from the telephoto end to the wide end (zoom area), the OVF cam cylinder 34
Is rotated, the cam follower 22b formed in the first moving frame 22a moves in the first cam groove 34a through a1 → a2 → a3.
Will move to Further, the cam follower 23b formed in the second moving frame 23a moves in the second cam groove 34b from b1 to b2 to b3. As a result, the first and second moving frames 22a and 23a become the first and second moving frames, respectively.
It moves in the optical axis direction according to the lift of the cam grooves 34a and 34b.

Here, the first cam groove 34a is an endless cam groove whose both ends (tele end and wide end) are smoothly continuous.

The cam follower 22b formed on the first moving frame 22a is moved by the retracting operation of the photographing zoom lens unit A from the wide end to the retracted end (retracted area).
Is again in the first cam groove 34a, a3 (a1) → a4
(A2) → a5 (a3).

That is, the first moving frame 22a (OVF first
The zoom lens 22) is entirely engaged with the first cam groove 34a, which is a zoom area cam section, both when the photographing zoom lens section A is in the zoom area and in the retracted area.

On the other hand, the second cam groove 34b is
A retractable area cam part 34b2 that engages only when the photographing zoom lens part A is in the retracted area continues from one end of the zoom area cam part 34b1 that drives the zoom lens 3a.
Are formed as cam grooves extending over approximately two turns.

For this reason, the cam follower 23b formed on the moving frame 23a is moved by the retracting operation of the photographing zoom lens unit A from the wide end to the retracted end (retracted area).
The inside of the collapsed area cam portion 34b of the second cam groove 34b is b3
→ b4 → b5.

As described above, when the photographing zoom lens unit A performs the retracting operation, the first moving frame 22 moves in the optical axis direction according to the lift of the first cam groove 34a, while the second moving frame 22 moves in the optical axis direction.
The moving frame 23 is kept almost stopped by the second cam groove 34b.

By setting the cam groove of the OVF cam cylinder 34 in this manner, as shown in FIG.
The second cam groove 34b can be made closer to the cam groove 34a in the cam cylinder axial direction. Therefore, the OVF cam cylinder 3
4 can be shortened in the axial direction, and the OVF section B can be compactly assembled. Furthermore, this OV
The entire photographing lens unit having the F portion B and the entire camera can be made compact.

The triangular prism 25 and the roof prism 26 shown in FIG. 2 are fixed to the OVF base member 31. O
VF objective lens 21, OVF first variable power lens 22, OV
The light beam passing through the F second variable power lens 23 and the fixed OVF lens 24 is reflected and bent by the triangular prism 25 and the roof prism 26 a total of five times, and finally, at a position separated by the distance T, the original OVF The light beam has an optical axis parallel to the optical axis, passes through the OVF eyepiece 27 and the OVF eyepiece window (protective glass) 28, and reaches the photographer's eyeball.

Next, the diopter adjustment mechanism will be described.
A sleeve portion 27b is formed on the eyepiece moving frame 27a that holds the OVF eyepiece lens 27 so as to fit with the guide bar 29 and receive the guide in the optical axis direction by the guide bar 29. Note that both ends of the guide bar 29 are fixed to the OVF base member 31 so as to be parallel to the OVF optical axis.

The diopter adjustment dial 37 is a dial that rotates around the axis of the stop screw 38. The diopter adjustment dial 37 has a cam groove 37a for adjusting the position of the eyepiece moving frame 27a in the OVF optical axis direction. Are formed.

The cam follower 27c provided near the sleeve portion 27b is provided with a cam groove 37 of the diopter adjustment dial 37.
When the diopter adjustment dial 37 is rotated in the range of ± 40 ° around the axis of the stop screw 38, the cam follower 27c of the eyepiece moving frame 27a moves along the cam groove 37a, and as a result, The OVF eyepiece 27 moves in the optical axis direction, and the diopter of the OVF unit A can be adjusted.

The click ball 40 is formed on an uneven surface provided on the back surface of the diopter adjusting dial 37 (for example, the unevenness formed by rotating the diopter adjusting dial 10 ° at one time) by the force of the coil spring 39. It is imposed. Thereby, diopter adjustment of ± 4 steps from the diopter adjustment reference can be performed. Therefore, it is possible to finely adjust the OVF diopter according to the variation of the diopter of the photographer.

In this embodiment, the case where two cam grooves 34a and 34b are formed in the cam cylinder 34 has been described. However, in the present invention, three or more cam grooves are formed in the cam cylinder (cam member). It can also be applied to the case.

[0041]

As described above, according to the present invention,
Since the other zoom area cam section can be provided closer to the zoom area cam section having both ends continuous in the axial direction of the cam member, the length of the cam member in the axial direction can be reduced, and the entire finder device (therefore, the taking lens) Unit and camera)
Can be made more compact.

If the zoom area cam having both ends continuous and the storage area cam section with which the finder lens engages when the taking lens is in the storage area have a continuous zoom area cam section, the cam can be provided. The required zoom performance of the finder optical system can be easily ensured while the members and the entire finder device are made compact.

[Brief description of the drawings]

FIGS. 1A and 1B are a front view and a plan view of an OVF unit constituting a taking lens unit according to an embodiment of the present invention. FIGS.

FIG. 2 is a rear view and a side sectional view of the OVF unit.

FIG. 3 is a development view of a cam cylinder of the OVF section.

FIG. 4 is a front view, a side view, a plan view, and a rear view of the photographing lens unit.

FIG. 5 is a development view of a conventional cam barrel of an OVF section.

[Explanation of symbols]

 A photographing zoom lens section B optical zoom finder (OVF) section 3 first lens barrel 4 front lens of photographing lens 5 main body cam gear 21 OVF objective lens 22 OVF first variable power lens 23 OVF second variable power lens 25 triangular prism 26 roof prism 27 OVF eyepiece 28 OVF eyepiece window (protective glass) 29, 33 Guide bar 30 OVF lid member 31 OVF base member 34 OVF cam cylinder 34 a, 34 b Cam groove 35 OVF cam gear 36 OVF camshaft 37 Diopter adjustment dial 39 Coil spring 40 Click ball

Claims (4)

[Claims] 1. A cam member which rotates in conjunction with the operation of a photographing lens in a zoom region and a storage region, and the cam member engages with each of a plurality of finder lenses to perform a zoom operation of the photographing lens. In the optical finder device formed with a plurality of zoom area cam sections for driving each of the plurality of finder lenses in accordance with the above, at least one end of the plurality of zoom area cam sections is rotated in the rotation direction of the cam member. An optical viewfinder apparatus, wherein the viewfinder lens is engaged with the zoom area cam section both when the photographing lens is in a zoom area and when it is in a storage area. 2. The cam member is connected to one end of a zoom area cam part other than the zoom area cam part whose both ends are continuous in the plurality of zoom area cam parts in the rotation direction of the cam member, 2. The optical viewfinder device according to claim 1, wherein a storage area cam portion with which the viewfinder lens is engaged when the photographing lens is in the storage area is formed. 3. A photographic lens unit comprising: the optical finder device according to claim 1; and a photographic lens operable in a zoom area and a storage area. 4. A camera comprising: the optical viewfinder device according to claim 1; and a photographing lens operable in a zoom region and a storage region.