JP2003185906A - Optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical device capable of accomplishing an appropriate optical performance by adjusting a backlash between a cam groove and a cam follower. <P>SOLUTION: The optical device is constituted so that one or more movable lenses are held in a housing, and a projection part arranged on the movable lens is engaged with the cam of a cam member which is driven in a controlled manner in a thrust direction and rotated around a holding member, and then, the movable lens is freely moved backward and forward in the thrust direction in accordance with the rotation of the cam member so as to focus or adjust the magnification. The cam member is supported in a state where the distance between the cam surface and the projection part is optionally set. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device such as a camera, a video camera or a digital still camera which drives a movable lens group of an optical system so as to move back and forth in the optical axis direction to perform focus adjustment and magnification control. is there.

[0002]

2. Description of the Related Art FIG. 1 is a view showing a conventional taking lens unit, which is composed of a taking zoom lens section and an optical zoom finder section (the taking zoom lens section and the optical zoom finder section are combined. It shows the state).

FIG. 1 is a front view, a side view, and a rear view from the bottom left, and the top is a top view. Here, as a typical zoom lens, a retractable zoom lens to which an optical zoom finder is attached is mentioned.

In FIG. 1, reference numeral 1 denotes a photographing zoom lens unit,
Reference numeral 2 is an optical zoom finder (OVF) portion, 3 is a retractable type first lens barrel, 4 is a front lens of a photographing lens, and 5 is a main body cam gear attached to the photographing lens portion.

Reference numeral 21 is an objective lens of an optical finder, 2
8 is an OVF eyepiece window, 34 is an OVF cam barrel, and 35 is an OVF
The cam gear 37 is a diopter adjustment dial. The V range in the figure represents the vertical angle of view of the optical viewfinder (when wide) (two-dot chain line), and the H range represents the horizontal angle of view of the optical viewfinder (when wide) (2 Dashed line). The distance D is the front lens 4 of the photographing lens and the OVF objective lens 2.
1 represents the distance between the optical axes and 1.

Next, the mutual operation relationship of FIG. 2 will be described.

Since the main photographing lens is a retractable type, the first lens barrel 3
Is at the position 3 when not being photographed and comes to the position 3 '(dotted line) when being photographed. Further, a plurality of variable magnification lenses (not shown) inside the lens barrel are driven by a lens barrel cam mechanism (not shown), and a zoom operation of the photographing lens is performed.

Usually, a zooming driving means (not shown)
Is a step motor or the like housed inside the lens barrel for downsizing, and drives the lens barrel cam mechanism via a gear train. The main body cam gear 5 is one of the gear trains. The main body cam gear 5 drives the lens barrel cam mechanism and, at the same time, rotates the OVF cam gear 35 to rotate the OVF cam barrel 34.
To rotate.

The OVF cam cylinder 34 is a first OVF cam which will be described later.
The zooming operation of the OVF is performed by driving the variable power lens and the second OVF lens.

Since the main taking lens is a retractable type, the first lens barrel 3
Is at the position 3 when not shooting and comes to the position 3'when shooting. Since the vertical angle of view of the OVF at this time is in the V range, a predetermined clearance must be provided between the first group lens barrel 3 ′ and the V range (because if this clearance is not present, the OVF is (When you look at it, you can see the first lens barrel 3.) Therefore, the distance D that determines the positions of the zoom lens unit 1 and the OVF unit 2 cannot be made smaller than a certain predetermined value, and therefore the zoom lens unit 1 and the OVF unit 2
There will be a space between and. Therefore, the main body cam gear 5, the OVF cam cylinder 34, and the OVF cam gear 35 are arranged in this space.

FIG. 2 is a view in which only the optical zoom finder portion of FIG. 1 is cut out and shown.

In FIG. 2, a bottom view, a front view, a top view, and a rear view are shown from the bottom left, and the top is a development view of the OVF cam cylinder 34 (the top view is for easy understanding of the internal structure. , The OVF part is shown with the lid member removed.

Reference numeral 21 is an OVF objective lens, 22 is a moving frame including an OVF first variable power lens, 23 is a moving frame including an OVF second variable power lens, 24 is a fixed OVF lens, 25 is a triangular prism, 26 is a roof prism, 27 is a moving frame including an OVF eyepiece lens, 28 is an OVF eyepiece window (protective glass),
29 is a guide bar, 30 is an OVF lid member, 31 is an OVF
A base member, 33 a guide bar, 34 an OVF cam barrel,
35 is an OVF cam gear, 36 is an OVF cam shaft, 37 is a diopter adjustment dial, 38 is a stop screw, 39 is a coil spring,
40 is a click ball.

Next, the mutual operation relationship of FIG. 2 will be described.

The OVF objective lens 21 and the fixed OVF lens 24 are fixed to the OVF section base member 31. O
A sleeve for fitting the guide bar 33 to the moving frame 22 including the VF first variable power lens and the moving frame 23 including the OVF second variable power lens, and for moving in the optical axis direction (left-right direction of the top view sheet). There are portions 22-a and 23-a, and the guide bar 3
Both ends of 3 are fixed to the OVF base member 31 in parallel with the optical axis.

The OVF cam cylinder 34 is a cylindrical cam cylinder, and
As shown in the VF cam development view, two cam grooves 34-a and 34-b are provided. Sleeve parts 22-a and 23
Since the cam follower and the cam follower provided in the vicinity of −a are engaged with the cam groove 34-a and the cam groove 34-b, respectively, when the OVF cam cylinder 34 rotates around the OVF cam shaft 36, Moving frame 2 including the first zoom lens
2 and the moving frame 23 including the OVF second variable power lens move along the cam groove to perform the OVF zoom operation.

When the zoom state is changed from tele to wide, the cam follower and the cam follower are respectively a1.
→ a2 → a3 → a4 → a5, b1 → b2 → b3 → b4 →
Each position comes in the order of b5. a1 and b1 are tele positions, and a5 and b5 are wide positions.

The OVF drive is performed so that the OVF cam gear 35 and the above-mentioned main body cam gear 5 mesh with each other.
When the main body cam gear 5 rotates and the OVF cam gear 35 rotates by combining the photographing lens barrel portion 1 with
The VF cam cylinder is rotated, for example, a step motor or DC
Attach an output gear to an actuator such as a motor, and
The OVF cam barrel 34 may be rotated in conjunction with the F cam gear 35. At this time, the output (rotation amount) of the above-mentioned actuator is electrically controlled so that the taking lens barrel 1 and the OVF can be controlled.
The magnification and focal length of the unit 2 are made to match.

The triangular prism 25 and the roof prism 26 are
It is fixed to the OVF base member 31. The light rays that have passed through the OVF objective lens 21, the OVF first variable power lens 22, the OVF second variable power lens 23, and the fixed OVF lens 24 are moved downward (on the paper surface of the top view) five times by the triangular prism 25 and the roof prism 26. It is reflected and bent, and finally becomes a light beam having an optical axis parallel to the original OVF optical axis at a position separated by a distance T, and the OVF eyepiece lens 27 and OV.
It reaches the photographer's eyeball through the F eyepiece window (protective glass) 28.

Further, the diopter adjusting mechanism will be described.

On the moving frame 27 including the OVF eyepiece,
There is a sleeve portion 27-a that fits with the guide bar 29 and moves in the optical axis direction (left and right direction of the top view sheet), and both ends of the guide bar 29 are fixed to the OVF base member 31 in parallel with the OVF optical axis. Has been done. The diopter adjustment dial 37
A cam groove 3 that is a dial that rotates around the axis of the stop screw 38 and that adjusts the position of the moving frame 27 in the OVF optical axis direction.
There is 7-a. Since the cam follower 27-b provided near the sleeve portion 27-a is engaged with the cam groove 37-a, the diopter adjustment dial 37 rotates about the axis of the stop screw 38 within a range of ± 40 °. Then, the cam follower 27-b of the moving frame including the OVF eyepiece lens is connected to the cam groove 37-a.
The OVF eyepiece lens moves in the optical axis direction (left-right direction of the top view sheet) as a result, so that the diopter adjustment of the OVF can be performed. At this time, as shown in the figure, the click ball 40 has an uneven surface (for example, an uneven surface provided on the back surface of the diopter adjustment dial 37 by the force of the coil spring 39).
The diopter adjustment dial is pressed against the diopter adjustment dial by rotating the dial 10 °), and the diopter can be adjusted in ± 4 steps from the diopter adjustment reference. Fine adjustment is possible according to the diopter variation of the photographer.

[0022]

By the way, the cam grooves 34-a and 34-b and the cam follower 22 in the above-mentioned conventional example.
Regarding the engagement states of -a and 23-b, the OVF cam cylinder 34
FIG. 3 shows a developed view of the cam grooves 34-a and 34-b installed in FIG. 3 and a cross section of the cam followers 22-a and 23-b.

In FIG. 3, cam followers 22-a, 2
3-b moves along the cam grooves 34-a and 34-b. At this time, the contact state between the cam followers 22-a and 23-b and the cam grooves 34-a and 34-b is, for example, tele-to-wide shift. When driving, only one surface of the cam grooves 34-a and 34-b of FIG.
In response to the action in the direction a, the force in the direction of the arrow 50-c, which is the Y-direction component of the action of the arrow 50-a, causes the OVF second
The variable power lens 23 is driven. At this time, the OVF first variable power lens 22 is also driven by the same action.

Here, the OVF first variable power lens 22, OV
When driving the F second variable power lens 23, a problem is
This is due to the action of the directional component of arrow 50-b.
The action of the directional component of the arrow 50-b is caused by the OVF first variable power lens 22, the OVF second variable power lens 23, and the guide bar 3.
It is a component that rotates about 3 as a center. Due to this rotational movement, for example, when a subject removes the OVF section 2, the image appears to shake during the zooming operation (this phenomenon is referred to as “image blur” here). If the zoom lens has a constant force acting on the directional component of the arrow 50-b, it does not matter, but during the zooming operation, the action of the directional component of the arrow 50-b does not act on the cam groove 34-. If it changes due to the influence of the accuracy of a, 34-b, etc.
May be noticeable, which may cause a problem in the product.

Further, there is always play between the cam grooves 34-a and 34-b and the cam followers 22-a and 23-b as shown in FIG. FIG. 3 shows the cam groove 34 when the distance is from tele to wide.
The contact states of the a, 34-b and the cam followers 22-a, 23-b are shown, but when this is driven from wide to tele, it comes into contact with the other surface to drive. That is, at the time of switching from tele-to-wide and wide-to-tele, the cam grooves 34-a and 34-b and the cam follower 22-.
OVF first variable magnification lens 2 by a play amount of a and 23-b
2. The OVF second variable power lens 23 rotates about the guide bar 33, which also contributes to "image blur".

In order to deal with the above problem, it is necessary that the cam groove and the cam follower are in a state where the backlash is as small as possible and smooth driving is possible in the tele-wide range. Also, considering the shrinkage of the material due to the temperature change of the member, very minute adjustment is required.

In the basic optical performance, the tele area is particularly sensitive and is affected by a slight deviation from the design value. Therefore, high cam surface accuracy and backlash setting are required. Is not required. This is OV
It is often said not only in F but also in general optical systems.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an optical device capable of exhibiting appropriate optical performance by adjusting the play of the cam groove and the cam follower.

[0029]

In order to achieve the above object, the present invention holds at least one or more movable lenses in a housing, and drives the protrusions installed on the movable lenses in the thrust direction. The cam of the cam member that is regulated and rotates around the holding member is engaged, and the movable lens is movable in the thrust direction by rotating the cam member,
An optical device for performing focus adjustment or magnification adjustment is characterized in that the cam member is supported in a state where a distance between the cam surface and the protrusion is arbitrarily set.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 4 shows a first embodiment of the present invention.
FIG. 6 is a diagram showing a configuration of a variable power lens 51, a second variable power lens 52, a cam ring 54, and a lens barrel 53 at the time of tele (i) and wide (ii). 4 (iii) is a sectional view of the guide bar 56 supporting the cam ring 54 and the bearing portion installed in a part of the lens barrel 53. FIG. 5 is a view showing the structure of the guide bar 56 and the elongated hole for adjusting the guide bar installed in a part of the lens barrel 53.

As shown in FIG. 4 (iii) and FIG. 4, one end of the support of the guide bar 56 supporting the cam ring 54 is a bearing,
The other end is supported by a movable long hole 57. The elongated hole 57 allows the guide bar 56 and the cam followers 51a, 5
Adjust the mutual positional relationship of 1b. In this adjusting mechanism, the cam ring 54 may be adjusted to a position inclined with respect to the optical axis. For the adjustment, the OVF drawing is performed, and while observing the drawing, the proper OVF driving, that is, the state in which the optical problem of the image sway cylinder does not occur, can be used as a guide to configure the positional relationship between the cam ring and the cam follower. . At this time, in the method of positioning the slot 57 and the guide bar 56 according to the present invention, in the present embodiment, the wedge 68 is used as a spacer as shown in FIGS. 4 and 5, and the guide bar 56 is fixed by adhesion 69. However, the guide bar 56 may be fixed by, for example, adjusting the guide bar 56 with a jig (not shown) and fixing it only by adhesion, as long as the guide bar 56 can be positioned and fixed.

When the above-described adjustment is applied to the development view (FIG. 2) of the cam ring 54, especially the second group of cam grooves 34-
The backlash of a can be adjusted. This is because the optical performance in the present embodiment is particularly sensitive to the second lens group, especially the telephoto side.

In the present invention, the rotation of the gear 66 is transmitted to the cam ring 54 to drive the two variable magnification lenses. However, it may be used in an optical system which does not have two variable magnification lenses, for example. Absent. Further, in the present invention, although the drive source of the gear 66 is not mentioned, it may be moved in conjunction with the zoom lens for photographing as in the conventional example.
For example, a magnetic motor such as a step motor or a DC motor may be used.

Considering the normally set play of the cam groove and the cam follower, the amount of play of the cam groove and the cam follower is small as described above, and therefore the gear 66 does not become unable to transmit the power after the adjustment.

<Second Embodiment> FIG. 6 shows a developed view of a cam ring in the present embodiment.

Comparing the development view of the cam ring (FIG. 2) in the first embodiment with the development view (FIG. 6) in the present embodiment, the tele position 60b of the cam groove 58 and the cam groove 60a of the cam groove 59 are compared. The positions in the rotation direction 67 are different, and the positions are substantially the same with respect to the object direction 62.

In the cam groove structure shown in FIG. 6,
When the adjustment of the present invention is performed by using the same mechanism as the cam ring 54 and the cam grooves 58 and 59 shown in FIGS. 4 and 5 similar to the first embodiment, the cam grooves 58 and 59 and the cam follower 51a at the tele position. , 51b can be adjusted. In other words, on the telephoto side, which has a high optical precision required for the image blur, if the high precision adjustment is performed and the play is adjusted in the entire tele-wide area, the OVF drive itself may be deteriorated. Therefore, on the wide side, adjustment based on the idea of leaving an appropriate amount of play can be performed.

In the present invention, the optical performance requirement on the tele side of the optical system is high. However, in the optical system other than the present embodiment, for example, when the optical performance requirement on the wide side is high, the bearing which is the support portion of the guide bar 56. It is also possible to install 58 and the long hole 57 in reverse so as to adjust the wide side. That is, it is possible to perform adjustments corresponding to various optical image blur sensitivity in a range in which the arrangement of the cam grooves can be changed.

When the cam grooves are arranged as shown in the cam ring development view of FIG. 6, the telescopic position 60 of the cam grooves 58 and 59.
The positions of a and 60b with respect to the rotation direction 67 are the same. As a result, the positions of the cam followers 51a and 52a are displaced in the cam ring rotation direction as shown in FIG. Further, when the cam grooves are arranged as in the cam ring development view of FIG. 6, the telescopic position 6 of the cam grooves 58 and 59 is shown.
Since 0a and 60b coincide with the object direction 62, as shown in FIG. 4 (ii), the arm 52b is extended from the second variable power lens 52, and the cutout portion 51b is formed in the first variable power lens 51. It is installed so that the arm 52b passes through the cutout portion 51b.

The relationship between the arm 52b and the cutout portion 51b in FIGS. 7 and 4 (ii) is that the arm 52b is inserted into the cutout portion 51b at or near the telephoto in FIG. 4 (i). In (ii), it will not be inserted. Utilizing this driving state, the arm 52b and the notch 51b
Is fitted and inserted, and the first variable magnification lens 5 in the telephoto
The behaviors of the first and second variable power lenses 52 are synchronized. for example,
Even if the image blur occurs, the first variable magnification lens 51 and the second variable magnification lens 52 are driven in synchronization with each other, so that the subject does not easily notice the image blur and does not cause discomfort. Play a supporting role.

[0042]

As is apparent from the above description, according to the present invention, at least one or more moving lenses are held in the housing, and the projections installed on the moving lenses and the driving in the thrust direction are performed. An optical element for adjusting the focus or magnification by engaging with a cam of a cam member that is regulated and rotates about the holding member, and the movable lens moves in the thrust direction by the rotation of the cam member. In the device, since the cam member is supported in a state where the distance between the cam surface and the protrusion is arbitrarily set, it is possible to exert appropriate optical performance by adjusting the play of the cam groove and the cam follower. can get.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a conventional optical zoom finder unit.

FIG. 2 is a diagram showing a state in which a conventional photographing zoom lens unit and an optical zoom finder unit are combined.

FIG. 3 is a development view of a conventional cam ring.

FIG. 4 is a configuration diagram of a first variable power lens, a second variable power lens and a cam ring of the present invention.

FIG. 5 is a diagram of a cam ring adjusting mechanism of the present invention.

FIG. 6 is a development view of a cam ring according to the present invention.

FIG. 7 is a configuration diagram of a first variable power lens cutout portion and a second variable power lens arm portion of the present invention.

[Explanation of symbols]

1 Shooting zoom lens section 2 Optical zoom finder (OVF) section 3 collapsible type first lens barrel 4 shooting lens front lens 5 Main body cam gear 21 Optical viewfinder objective lens 22 Moving frame including OVF first zoom lens 23 OVF Moving frame including the second zoom lens 24 fixed OVF lens 25 triangular prism 26 Dach Prism 27 Moving frame including OVF eyepiece 28 OVF eyepiece window (protective glass) 29 Guide bar 30 OVF lid member 31 OVF base member 33 Guide bar 34 OVF Cam Tube 35 OVF cam gear 36 OVF camshaft 37 Diopter adjustment dial 38 Stop screw 39 coil spring 40 click ball 51 1st variable power lens

Claims (4)

[Claims] 1. A cam of a cam member, which holds at least one or more movable lenses in a housing, and which rotates around a protrusion provided on the movable lens and a holding member whose drive in the thrust direction is restricted. And are engaged with each other, and the cam member is rotated to move the movable lens in the thrust direction,
An optical device for performing focus adjustment or magnification adjustment, wherein the cam member is supported in a state in which the distance between the cam surface and the protrusion is arbitrarily set. 2. The optical device according to claim 1, wherein the cam member is movable, and the distance between the cam surface of the cam member and the protrusion is arbitrarily set. 3. The cam member is rotatably supported by a guide member, and the guide member is supported in both a parallel state and a non-parallel state with respect to the optical axis. Optical device. 4. The optical device according to claim 1, wherein at least the positions of the cam surface of the cam member in the tele and wide positions in the optical axis direction do not match.