JP7163244B2 - optical equipment - Google Patents

Description

The present invention relates to an interchangeable lens, an imaging device, or other optical equipment that moves a lens in the optical axis direction using a cam member.

In the optical apparatus as described above, the distance between lenses adjacent to each other in the optical axis direction can be made as narrow as possible, thereby securing the amount of movement of the movable lens during zooming.

However, in order to prevent the adjacent lenses from colliding with each other when an external force such as an impact is applied to the optical device, a lens and a lens holding member for holding the adjacent lens are separated as disclosed in Patent Document 1. A configuration is adopted in which these lenses are brought into contact with each other before they are brought into contact with each other.

JP 2011-017930 A

However, in the structure in which a lens and a lens holding member adjacent thereto are brought into contact with each other as disclosed in Japanese Patent Laid-Open No. 2002-200014, there is a risk that the lens with which the lens holding member abuts may be damaged, such as a scratch or a crack.

SUMMARY OF THE INVENTION The present invention provides an optical instrument capable of reducing lens damage when an external force is applied.

An optical apparatus as one aspect of the present invention includes a base member, a first lens holding member that holds a first lens and is movable in the optical axis direction with respect to the base member, and is arranged on the image side of the first lens. a second lens holding member that holds the second lens and is movable with respect to the base member in the optical axis direction; a cam member having a first cam portion and a second cam portion that engage with the provided first cam follower and the second cam follower provided on the second lens holding member, respectively. One of the base member and the cam member has a third cam portion that moves the cam member relative to the base member in the optical axis direction by rotation of the cam member. A stopper portion is provided on the cam member. In the first state where the distance between the first lens and the second lens in the optical axis direction is the shortest first distance, the second lens holding member is the second distance in the optical axis direction with respect to the stopper portion. It has a stopper receiving part that approaches up to. The second distance is shorter than the first distance.

According to the present invention, it is possible to reduce damage when an external force is applied to an optical device.

1 is an exploded perspective view of an interchangeable lens device that is an embodiment of the present invention; FIG. 1 is a first cross-sectional view of an interchangeable lens device according to an embodiment; FIG. 4 is a perspective view of the first lens holding member in the interchangeable lens device of the embodiment; FIG. FIG. 4 is a perspective view of a second lens holding member in the interchangeable lens device of the embodiment; 4 is a perspective view of a cam cylinder in the interchangeable lens device of the embodiment; FIG. FIG. 3 is a perspective view of a guide cylinder in the interchangeable lens device of the embodiment; 2 is a second cross-sectional view of the interchangeable lens device of the embodiment; FIG. 4 is a perspective view of an operation ring in the interchangeable lens device of the embodiment; FIG. 3 is a third cross-sectional view of the interchangeable lens device of the embodiment; FIG. 4 is a fourth cross-sectional view of the interchangeable lens device of the embodiment; FIG. 5 is a fifth cross-sectional view of the interchangeable lens device of the embodiment; FIG. The figure which expanded a part of FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 show the configuration of an interchangeable lens device (optical device) that can be attached to and detached from an imaging device such as a digital camera or video camera. The interchangeable lens device has a first lens 101 and a second lens in order from the object side (hereinafter also referred to as the front side) on the left side of the drawing to the image side (image plane side: hereinafter also referred to as the rear side) on the right side of the drawing. 104 , a third lens 114 and a fourth lens 115 . These first to fourth lenses 101, 104, 114 and 115 constitute an imaging optical system. Each of the first to fourth lenses 101, 104, 114, 115 is composed of one or a plurality of lenses, and can also be called a lens group or a lens unit. A in FIG. 2 indicates the optical axis of the imaging optical system, the direction in which the optical axis A extends is called the optical axis direction, and the direction perpendicular to the optical axis A is called the radial direction. A circumferential direction around the optical axis A is referred to as a direction around the optical axis or a circumferential direction. The first to fourth lenses 101, 104, 114 and 115 are independently moved in the optical axis direction to perform zooming.

A first lens holding member 102 holds the first lens 101 . FIG. 3 shows the first lens holding member 102 viewed obliquely from the rear side. Reference numeral 103 denotes first cam followers attached to the inner peripheral portion of the first lens holding member 102 at three locations in the circumferential direction. Fourth cam followers 119 are attached to the outer peripheral portion of the first lens holding member 102 at three locations in the circumferential direction. Each of the first and fourth cam followers 106 and 119 has a through hole at its center, and the male threaded portion of the screw inserted therein is tightened into the female threaded portion of the first lens holding member 102, thereby opening the first lens. It is fixed to the holding member 102 .

In FIGS. 1 and 2, 105 is a second lens holding member that holds the second lens 104 . FIG. 4 shows the second lens holding member 105 as viewed obliquely from the front side. Second cam followers 106 are attached to the outer peripheral portion of the second lens holding member 105 at three locations in the circumferential direction in the same manner as the first and fourth cam followers 103 and 119 .

As shown in FIG. 2, the maximum outer diameter D1 of the first lens 101 is set larger than the maximum outer diameter D2 of the second lens holding member 105 (the maximum outer diameter of the cylindrical portion excluding the second cam follower 106). there is

In FIGS. 1 and 2, 107 is a cam cylinder as a cam member, and 108 is a guide cylinder as a guide member arranged radially inside the cam cylinder 107 . The rear end of the guide tube 108 is integrally fixed to the fixed tube 110, and together with the fixed tube 110 constitutes a base member of the interchangeable lens device.

The cam barrel 107 is rotatable around the optical axis with respect to the guide barrel 108 on the outer circumference of the guide barrel 108 . FIG. 5 shows the cam cylinder 107 as viewed obliquely from the front side. The cam cylinder 107 has a radial fitting portion 107h that radially fits with the outer peripheral portion of the guide cylinder 108 on its inner peripheral portion. The cam tube 107 has a first cam groove portion 107a as a first cam portion that engages with the first cam follower 103 and a second cam groove portion 107b as a second cam portion that engages with the second cam follower 106. Three lines are formed in each direction. 9 and 10 show the state in which the first and second cam followers 103, 106 are engaged with the first and second cam grooves 107a, 107b, respectively.

The cam cylinder 107 has a third cam portion that engages with third cam followers 109 attached at three locations in the circumferential direction on the outer periphery of the guide cylinder 108 as shown in FIG. Three third cam groove portions 107c are formed in the circumferential direction. FIG. 7 shows a state in which the third cam follower 109 is engaged with the third cam groove portion 107c. The third cam portion may be provided on one of the cam cylinder 107 and the guide cylinder 108 , and the third cam follower may be provided on the other of the cam cylinder 107 and the guide cylinder 108 .

Further, cam followers 114b and 115b provided on the outer periphery of a fourth lens holding member 114a holding a fourth lens 114 and a fifth lens holding member 115a holding a fifth lens 115 are engaged with the cam cylinder 107, respectively. Three cam grooves 117i and 117j are formed in the circumferential direction. FIG. 9 shows the cam followers 114b and 115b engaged with the cam grooves 117i and 117j, respectively.

As shown in FIGS. 2 and 5, stopper portions 116a project radially inward from the cam cylinder 107 at three locations in the vicinity of the front end of the cam cylinder 107 in the circumferential direction. The stopper portion 116a is provided using a threaded member 116 having a male threaded portion near the head portion and a tip shaft portion having a smaller diameter than the male threaded portion on the distal end side of the male threaded portion. That is, the stopper portion 116a is provided using a member separate from the cam cylinder 107. As shown in FIG. The screw member 116 is fixed to the cam cylinder 107 by screwing its male threaded portion into a female threaded hole formed in the cam tube 107, and the tip shaft protruding radially inward of the cam tube 107 from the female threaded hole serves as a stopper. 116a.

Stopper receiving portions 105a are formed on the front surface of the second lens holding member 105 shown in FIG. 4 at three locations in the circumferential direction corresponding to the three stopper portions 116a. In the second lens holding member 105, the stopper receiving portion 105a is provided at a different position (phase) in the circumferential direction from the second cam follower 106, and has a shape slightly recessed rearward from the front surface of the second lens holding member 105 (Fig. 2). As a result, the movement stroke can be ensured by arranging the guide groove portion with which the second cam follower 106, which will be described later, is engaged without being obstructed by the stopper portion 116a.

1 and 2, reference numeral 111 denotes a mount for detachably attaching the interchangeable lens device to an imaging device 117 such as a digital camera. The imaging device 117 includes an imaging device 118 that photoelectrically converts (captures) a subject image, which is an optical image formed by the imaging optical system.

112 is an operation ring. As shown in FIG. 9, the operation ring 112 is coupled to the bayonet portion 110a of the fixed barrel 110 so as to be rotatable about the optical axis. be. As shown in FIGS. 1 and 2, a rubber ring 113 is attached to the outer peripheral surface of the operation ring 112 to prevent slipping when the user rotates the operation ring 112 . Further, as seen obliquely from the front side in FIG. A fourth cam follower 119 attached to the first lens holding member 102 is engaged with the fourth cam groove portion 112a.

The guide tube 108 shown in FIG. 6 includes a first guide portion that engages with the first cam follower 103 to guide the first lens holding member 107 in the optical axis direction (prevents rotation in the direction around the optical axis). and a second guide groove portion 108b as a second guide portion that engages with the second cam follower 106 and guides the second lens holding member 106 in the optical axis direction linearly in the optical axis direction. formed to extend. The first guide groove portion 108a and the second guide groove portion 108b are respectively provided at three locations in the guide cylinder 108 in the circumferential direction. Although the first guide groove portion 108a and the second guide groove portion 108b are provided separately in this embodiment, they may be integrated as one guide groove portion.

Near the front end of the outer circumference of the guide cylinder 108, as shown in FIG. is attached by the method of FIG. 7 shows the third cam follower 109 engaging with the third cam groove portion 107c. Further, as shown in FIG. 6 , a radial fitting portion 108 e that is radially fitted with a radial fitting portion 107 h of the cam cylinder 107 is formed on the outer peripheral portion of the guide cylinder 108 .

In the interchangeable lens device configured as described above, when the operation ring 112 is rotated, the fourth cam groove portion 112 a provided in the operation ring 112 moves to the fourth cam follower 119 provided in the first lens holding member 102 . rotate with respect to Therefore, the first lens holding member 102 is driven in the optical axis direction via the fourth cam follower 119 by the lift of the fourth cam groove portion 112a. When the first lens holding member 102 is driven in the optical axis direction, the first cam follower 103 provided on the first lens holding member 102 moves the cam barrel 107 through the first cam groove portion 107a provided on the cam barrel 107. It rotates around the optical axis. The cam barrel 107 is driven in the optical axis direction with respect to the guide barrel 108 by engaging the third cam follower 109 provided on the guide barrel 108 with the third cam groove portion 107c.

When the cam cylinder 107 rotates, the second lens holding member 105 is driven in the optical axis direction by engaging the second cam follower 106 provided on the second lens holding member 105 with the second cam groove portion 107b. be done. Since the cam cylinder 107 rotates while moving in the optical axis direction, the second lens holding member 105 is driven in the optical axis direction by the sum of the amount of movement of the cam cylinder 107 in the optical axis direction and the lift of the second cam groove portion 107b. be done.

Similarly, the cam followers 114b and 115b provided on the fourth and fifth lens holding members 114a and 115a are engaged with the cam grooves 107i and 107j, so that the fourth and fifth lens holding members 114a and 115a are engaged with each other. axially driven. At this time, the fourth and fifth lens holding members 114a and 115a are driven in the optical axis direction by the sum of the amount of movement of the cam cylinder 107 in the optical axis direction and the lift of the cam groove portions 107i and 107j.

In the cam barrel 107 shown in FIG. 5, an engagement position 107d of the second cam portion 107b at which the second cam follower 106 engages in the wide-angle end (WIDE) state and an engagement position 107d in which the second cam follower 106 engages in the telephoto end (TELE) state. Let C be the difference in the optical axis direction from the position 107e, that is, the amount of movement of the second lens 104 (second lens holding member 105) between the WIDE state and the TELE state. In this embodiment, the second lens 104 moves from the object side to the image side in the optical axis direction from the WIDE state to the TELE state.

The difference in the optical axis direction between the engagement position 107f where the third cam follower 109 engages in the WIDE state and the engagement position 107g where the third cam follower 109 engages in the TELE state in the third cam groove portion 107c, that is, the WIDE state and the TELE state. In this embodiment, the cam barrel 107 moves from the image side toward the object side from the WIDE state toward the TELE state.

In this embodiment, the first cam groove portion 107a and the second cam groove portion 107b are grooves penetrating the cylindrical portion of the cam cylinder 107 in the radial direction in order to ensure the strength of the cam cylinder 107 in which a large number of cam groove portions are formed. While formed in a shape, the third cam groove portion 107c is formed in a groove shape that does not penetrate the cylindrical portion.

Further, as shown in FIG. 6, recesses 108c are formed at three locations in the circumferential direction on the front end of the guide tube 108 so as to accommodate the three stopper portions 116a provided on the cam tube 107 in the optical axis direction. . The concave portion 108c accommodates the stopper portion 116a at least in the WIDE state, thereby preventing the stopper portion 116a and the guide tube 108 from interfering with each other. The recessed portion 108c is provided at a position different in the circumferential direction from the first guide groove portion 108a and the second guide groove portion 108b in the guide cylinder 108 . The first guide groove portion 108a and the second guide groove portion 108b extend forward from the rear end surface (bottom surface) of the recess portion 108c. With such a configuration, the length of the guide tube 108 in the optical axis direction is not extended, and the required length of the first and second guide grooves 108a and 108b is ensured. interference can be avoided.

2, 7, 9 and 10 show the WIDE state as a state (first state) in which the first lens 101 and the second lens 104 are closest in the optical axis direction. In this state, when the user drops the interchangeable lens device and the first lens holding member 102 collides with the ground or the like, the impact causes the first lens holding member 102 to move from the operation ring 112 and the cam cylinder 107 to the cam follower and the cam groove. It is displaced to the image side due to backlash between them and deformation of each member. On the other hand, the second lens holding member 105 is displaced toward the object side with respect to the cam cylinder 107 due to inertial force corresponding to its weight. As a result, the distance between the first lens 101 and the second lens 104 becomes narrower than in the WIDE state, and the first lens 101 and the second lens 104 may abut (collide). If the distance in the optical axis direction between the first lens 101 and the second lens 104 in the WIDE state is increased in order to avoid such contact between the first lens 101 and the second lens 104, optical design constraints.

For this reason, in the present embodiment, as described above, the cam cylinder 107 is provided with the stopper portion 116a projecting radially inward, and the stopper portion 116a can contact the second lens holding member 105 in the optical axis direction. A portion 105a is provided. In the normal WIDE state, a small space is provided between the stopper portion 116a and the stopper receiving portion 105a in the optical axis direction.

FIG. 11 shows cross sections of the interchangeable lens device of this embodiment in the TELE state and the WIDE state. The TELE state is shown on the upper side of the figure, and the WIDE state is shown on the lower side. By rotating the operation ring 112 from the WIDE state to the TELE state, the first lens 101 and the second lens 104 move toward the object side. At this time, the cam cylinder 107 also moves toward the object side while rotating around the optical axis.

The movement amount A of the cam barrel 107 in the optical axis direction from the WIDE state to the TELE state is the lift amount of the third cam groove portion 107c corresponding to the amount of rotation of the cam barrel 107 about the optical axis from the WIDE state to the TELE state. is. The movement amount B of the second lens 104 in the optical axis direction from the WIDE state to the TELE state is equal to the movement amount A of the cam barrel 107, and the rotation of the cam barrel 107 about the optical axis from the WIDE state to the TELE state. This is an amount obtained by adding a movement amount C corresponding to the lift amount of the second cam groove portion 107b corresponding to the amount.

Here, as shown in FIG. 5, the second cam groove portion 107b is formed in the cam barrel 107 so as to be located closer to the image side as the WIDE state approaches the TELE state. Further, the third cam groove portion 107c is formed in the cam barrel 107 so as to be located closer to the object side as the WIDE state approaches the TELE state. Therefore, the amount of movement of the cam cylinder 107 from the WIDE state in all zoom states (second state) other than the WIDE state in the zoom region (optical effective region) from the WIDE state (first state) to the TELE state A becomes larger than the movement amount B of the second lens 104 . In other words, the movement amount B of the second lens 104 is smaller than the movement amount A of the cam barrel 107 in all zoom states other than the WIDE state.

Therefore, the optical axis direction distance between the stopper portion 116a provided on the cam barrel 107 and the stopper receiving portion 105a of the second lens holding member 105 is It is shortest in the closest WIDE state (first state) and sufficiently long in other zoom states (second state). Moreover, as shown in FIG. 12, in the WIDE state, the optical axis direction distance (first distance) L1 between the stopper portion 116a and the stopper receiving portion 105a of the second lens holding member 105 is the closest. It is shorter than the optical axis direction distance (second distance) L2 between the first lens 101 and the second lens 104 .

Therefore, even in the WIDE state (and any other zoom state), when an external force such as an impact acts on the interchangeable lens device, the stopper portion 116a and the second lens 104 do not contact each other before the first lens 101 and the second lens 104 come into contact with each other. Abutment between the first lens 101 and the second lens 104 is avoided by abutting the two-lens holding member 105 .

As described above, according to this embodiment, it is possible to avoid or reduce damage to the first and second lenses 101 and 104 when an external force is applied to the interchangeable lens device. It is possible to increase the degree of freedom of arrangement, in other words, to reduce restrictions on optical design.

In the above embodiments, the interchangeable lens apparatus has been described, but the embodiments of the optical apparatus of the present invention include an image pickup apparatus in which an image pickup optical system is provided integrally (non-removably), and a lens barrel that is integrally attached to the image pickup apparatus. including.

Further, in the above embodiment, the case where the rotation of the operation ring 112 causes the first lens holding member 102 to move in the direction of the optical axis, and the movement of the first lens holding member 102 causes the cam barrel 107 to rotate around the optical axis has been described. However, the cam barrel may be rotated by the rotation of the operation ring, and the cam portion provided on the cam barrel may move the first and second lens holding members in the optical axis direction.

Each embodiment described above is merely a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

101 First lens 102 First lens holding member 104 Second lens 105 Second lens holding member 107 Cam barrel 108 Guide barrel 116a Stopper portion

Claims (7)

a base member;
a first lens holding member that holds a first lens and is movable in the optical axis direction with respect to the base member;
a second lens holding member that holds a second lens arranged closer to the image side than the first lens and is movable in the optical axis direction with respect to the base member;
A second cam follower that is rotatable about the optical axis with respect to the base member and engages with each of a first cam follower provided on the first lens holding member and a second cam follower provided on the second lens holding member. a cam member having a first cam portion and a second cam portion;
one of the base member and the cam member has a third cam portion for moving the cam member relative to the base member in the optical axis direction by rotation of the cam member;
The cam member is provided with a stopper portion,
In a first state in which the distance in the optical axis direction between the first lens and the second lens is the shortest first distance, the second lens holding member is arranged to hold the optical axis with respect to the stopper portion. has a stopper receiving portion that approaches a second distance in a direction,
An optical instrument, wherein the second distance is shorter than the first distance. 2. An optical instrument according to claim 1, wherein the maximum outer diameter of said first lens is larger than the maximum outer diameter of said second lens holding member. Between the first state and the second state, which are all states in which the position of the second lens holding member in the optical axis direction differs from the first state, the position of the cam member from the first state is changed. 3. The optical apparatus according to claim 1, wherein the amount of movement in the direction of the optical axis is larger than the amount of movement of the second lens holding member in the direction of the optical axis. 4. The optical apparatus according to any one of claims 1 to 3, wherein the base member has a concave portion that accommodates, in the first state, the stopper portion that moves in the optical axis direction together with the cam member. . the base member has a first guide portion and a second guide portion that guide the first lens holding member and the second lens holding member, respectively, in the optical axis direction;
5. The optical device according to claim 4, wherein the concave portion is provided at a different position from the first guide portion and the second guide portion in the direction around the optical axis in the base member. 6. The second lens holding member according to any one of claims 1 to 5, wherein the stopper receiving portion is provided at a position different from that of the second cam follower in the direction around the optical axis. optics. 7. The optical apparatus according to any one of claims 1 to 6, wherein the stopper portion is provided by attaching a member different from the cam member.

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