JP7016651B2 - Lens unit and optical equipment - Google Patents

Description

The present invention relates to a lens unit and an optical device.

Conventionally, a lens unit that performs focusing or zooming by moving an optical element is known. The lens unit is generally a lens barrel that holds an optical element, a cam follower attached to the lens barrel, a fixed cylinder having a straight groove formed parallel to the optical axis, and an angle with respect to the optical axis direction. It has a cam ring in which a cam groove is formed. For focusing or zooming, the cam follower fits into the straight groove so that it can move in the optical axis direction, and also fits in the cam groove so that it moves in the optical axis direction along the straight groove according to the rotation of the cam ring. It fits.

However, the fitting state of the cam follower with the straight groove and the cam groove changes depending on the component tolerance. The mating state also changes due to linear expansion due to temperature changes, moisture absorption at high humidity, or wear caused by repeated use. If the fitting is weakened and looseness occurs, the lens barrel will tilt or parallel eccentricity due to the looseness, and the optical performance will deteriorate. On the contrary, when the fitting becomes strong, the torque at the time of rotation of the cam ring increases, and focusing or zooming cannot be performed smoothly.

In order to solve the above problem, in Patent Document 1, the direction in which the first cam follower connected to the first lens barrel and the second cam follower connected to the second lens barrel intersect each other with the optical axis direction. An optical device having a urging means for urging is disclosed.

Japanese Unexamined Patent Publication No. 2013-257369

In recent years, due to the high resolution support of the lens unit, the number of lens barrels that move during focusing or zooming has increased, so that the number of lens barrels that are highly sensitive to tilting and parallel eccentricity has increased. Further, the lens unit is required to be further miniaturized.

However, Patent Document 1 does not disclose a configuration for suppressing the occurrence of backlash when three or more lens barrels are in close proximity to each other. Even if the lens barrels are urged to each other, the urging force for removing the backlash of the cam groove and the cam follower or the straight groove and the cam follower may be canceled out, and the deterioration of the optical performance may not be suppressed. Further, depending on the mounting position of the urging means, it is necessary to increase the size of the urging means, which may lead to an increase in the size of the lens unit.

An object of the present invention is to provide a lens unit and an optical device that can be miniaturized while suppressing deterioration of optical performance.

The lens unit as one aspect of the present invention is arranged on the optical device main body side with respect to the first lens barrel to which the first cam follower is attached and the first lens barrel in the optical axis direction. A second lens barrel to which the second cam follower is attached, and a third lens arranged on the main body side of the optical device with respect to the second lens barrel in the optical axis direction and to which the third cam follower is attached. The lens barrel and the first cam groove, the second cam groove, and the third cam groove into which the first cam follower, the second cam follower, and the third cam follower are fitted, respectively, have an angle with respect to the optical axis direction. A fixed cylinder in which a first cam follower, a second cam follower, and a straight groove into which a third cam follower is fitted are formed along an optical axis, and a first and second cam followers. A first urging means for urging the lens barrel in a direction intersecting the optical axis direction, and a second urging means for urging the second and third lens barrels in a direction intersecting the optical axis direction. And, two lens barrels corresponding to the larger spread between the first cam groove and the second cam groove and the wider spread between the second cam groove and the third cam groove. The urging force of the first or second urging means for urging the lens barrel is stronger than the urging force of the first or second urging means for urging the two lens barrels corresponding to the smaller spread. It is characterized by.

According to the present invention, it is possible to provide a lens unit and an optical device that can be miniaturized while suppressing deterioration of optical performance.

It is an exploded perspective view of the lens unit which concerns on embodiment of this invention. It is explanatory drawing of the method of attaching a coil spring to a lens barrel. It is a top view and a side view of a zoom cam ring. It is a figure which shows the moving amount and the tilting amount of each lens barrel corresponding to the sensitivity which breaks the standard of three lens barrels, the weight of each lens barrel, and the intersection angle of a cam groove and a straight groove. It is a schematic diagram of the liquid crystal projector provided with the lens unit of this embodiment. It is a schematic diagram of the image pickup apparatus provided with the lens unit of this embodiment.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings. In each figure, the same member is given the same reference number, and duplicate description is omitted.

FIG. 1 is an exploded perspective view of the lens unit 100 according to the embodiment of the present invention. The lens unit 100 is used by being attached to an optical device main body such as a projector or a camera. The first lens barrel 101, the second lens barrel 102, the third lens barrel 103, the fourth lens barrel 104, the fifth lens barrel 105, and the sixth lens barrel 106 are the first lens group, the second lens group, and the third lens group, respectively. It holds a lens group, a fourth lens group, a fifth lens group, and a sixth lens group. Cam followers 108A to 108F are attached to the outer circumferences of the first to sixth lens barrels 101 to 106 at three locations every 120 degrees in the circumferential direction with screws, respectively.

A mount 112 is screwed to the rear end of the fixed cylinder 111 in the optical axis direction (the end on the sixth lens barrel side). The mount 112 is formed with a flange portion to be attached to the main body of the optical device. A sixth lens barrel 106 holding a relay lens as a sixth lens group is fixed to the rear end of the mount 112 via a cam follower 108F. The focus cam ring 113 is arranged on the front side (first lens barrel side) of the outer circumference of the fixed cylinder 111. Further, the focus cam ring 113 has a gear portion and rotates about the optical axis 116 of the lens unit 100. The zoom cam ring 114 is arranged on the rear side (sixth lens barrel side) of the inner circumference of the fixed cylinder 111, and rotates about the optical axis 116. The zoom ring 115 has a gear portion and is attached to the outer periphery of the fixed cylinder 111 so as to rotate integrally with the zoom cam ring 114 via a connecting member (not shown).

The motor unit 121 includes a motor body such as a stepping motor, a DC motor, and a vibration type motor, and a reduction gear box that decelerates and outputs the rotation of the motor body, and functions as an actuator. The motor unit 121 is fixed to the holding member 122 by screws. When the holding member 122 is fixed to the fixing cylinder 111 with a screw, the motor unit 121 is in a state of meshing with the gear portion of the focus cam ring 113 and the gear portion of the zoom ring 115.

Hereinafter, the focus mechanism will be described. The first lens barrel 101 holds a focal position adjusting lens. In the present embodiment, focusing is performed by moving the first lens barrel 101 along the optical axis 116.

The cam follower 108A of the first lens barrel 101 fits into the straight groove 111A formed along the optical axis 116 at three positions of the fixed cylinder 111 every 120 degrees in the circumferential direction. Further, the cam follower 108A fits into the cam groove 113A formed so as to have an angle with respect to the optical axis direction at three positions of the focus cam ring 113 at every 120 degrees in the circumferential direction. The focus cam ring 113 can rotate around the optical axis 116 in a state where the fixed cylinder 111 is prevented from moving in the optical axis direction by a bayonet coupling structure or the like.

When the motor unit 121 meshed with the gear portion of the focus cam ring 113 is driven, the driving force is transmitted to the gear portion of the focus cam ring 113, and the focus cam ring 113 rotates. When the focus cam ring 113 rotates, the cam follower 108A moves in the optical axis direction along the cam groove 113A and the straight groove 111A. By this movement, the first lens barrel 101 moves along the optical axis 116, and focusing is performed.

Hereinafter, the zoom mechanism will be described. The second to fifth lens barrels 102 to 105 each hold a variable magnification lens as a second to fifth lens group. In the present embodiment, zooming is performed by moving the second to fifth lens barrels 102 to 105 along the optical axis 116.

The cam followers 108B to 108E of the second to fifth lens barrels 102 to 105 are fitted into the straight grooves 111B formed along the optical axis 116 at three positions of the fixed cylinder 111 at every 120 degrees in the circumferential direction. .. Further, the cam followers 108B to 108E are fitted into the first to fourth cam grooves 114A to 114D formed so as to have an angle with respect to the optical axis direction at three positions of the zoom cam ring 114 at every 120 degrees in the circumferential direction. It fits. The zoom cam ring 114 and the zoom ring 115 can rotate around the optical axis 116 in a state where the fixed cylinder 111 is prevented from moving in the optical axis direction by a bayonet coupling structure or the like.

When the motor unit 121 that meshes with the gear portion of the zoom ring 115 is driven, the driving force is transmitted to the gear portion of the zoom ring 115, and the zoom ring 115 rotates. When the zoom ring 115 rotates, the zoom cam ring 114 also rotates around the optical axis 116. When the zoom cam ring 114 rotates, the cam followers 108B to 108E move in the optical axis direction along the first to fourth cam grooves 114A to 114D and the straight groove 111B, respectively. By this movement, the second to fifth lens barrels 102 to 105 move along the optical axis 116, and zooming is performed.

Hereinafter, a coil spring (first lens barrel) is attached to the third lens barrel (first lens barrel) 103, the fourth lens barrel (second lens barrel), and the fifth lens barrel (third lens barrel) 105. A method of attaching the urging means) 107 and the coil spring (second urging means) 109 will be described. FIG. 2 is an explanatory diagram of a method of attaching the coil springs 107 and 109 to the third to fifth lens barrels 103 to 105. The fourth lens barrel 104 is arranged on the optical device main body side of the third lens barrel 103, and the fifth lens barrel 105 is arranged on the optical device main body side of the fourth lens barrel 104. The coil springs 107 and 109 are used to remove backlash in both the cam followers 108B to 108E and the first to fourth cam grooves 114A to 114D, and the cam followers 108B to 108E and the straight groove 111B.

In the coil spring 107, after the rotation control shaft 103B provided in the third lens barrel 103 is inserted into the rotation control hole 104B formed in the fourth lens barrel 104, the third lens barrel 103 and the fourth lens barrel 104 are screwed. Attached to. The coil spring 107 urges the third lens barrel 103 and the fourth lens barrel 104 in a direction intersecting the optical axis direction. Further, in the coil spring 109, after the rotation regulation shaft 105B provided in the fifth lens barrel 105 is inserted into the rotation regulation hole 104B formed in the fourth lens barrel 104, the fourth lens barrel 104 and the fifth mirror are screwed. It is attached to the cylinder 105. The coil spring 109 urges the fourth lens barrel 103 and the fifth lens barrel 104 in a direction intersecting the optical axis direction.

3 (a) and 3 (b) are a top view and a side view of the zoom cam ring 114, respectively. In the present embodiment, the third cam groove 114C and the fourth cam groove (the third cam groove 114C) are compared with the spread between the second cam groove (first cam groove) 114B and the third cam groove (second cam groove) 114C. The spread between the third cam groove) 114D is large. In other words, the difference between the maximum value and the minimum value of the distance between the third cam groove 114C and the fourth cam groove 114D in the optical axis direction is the difference between the second cam groove 114B and the third cam groove 114C in the optical axis direction. It is larger than the difference between the maximum and minimum values of the distance. In the present embodiment, since the coil spring 109 has a larger expansion / contraction amount than the coil spring 107, the urging force of the coil spring 109 is set stronger than the urging force of the coil spring 107. At this time, the coil spring 109 urges the fifth lens barrel 105 on the side where the angle of intersection between the fourth cam groove 114D and the straight groove 111B is wide. Further, the coil spring 107 urges the fourth lens barrel 104 on the side where the intersection angle between the third cam groove 114C and the straight groove 111B is wide. The distance between the cam grooves in the optical axis direction is the distance between the center positions of the groove widths in the optical axis direction of each cam groove.

Further, in the present embodiment, the urging forces of the coil springs 107 and 109 are set to be stronger than the own weights of the third and fifth lens barrels 103 and 105, respectively. Further, the sum of the urging forces of the coil springs 107 and 109 is set to be stronger than the own weight of the fourth lens barrel 104.

FIG. 4 shows the amount of movement and tilt of each lens barrel corresponding to the sensitivity that breaks the standard of the third lens barrel 103, the fourth lens barrel 104, and the fifth lens barrel 105, the weight of each lens barrel, and the cam groove. The angle of intersection between the mirror and the straight groove is shown. As shown in FIG. 4, since the values that divide the standard differ depending on each lens barrel, the urging force of the coil springs 107 and 109 is set based on at least one of the sensitivity, weight, and cross angle of each lens barrel. It is desirable to do.

As described above, the present invention can provide a lens barrel that can be miniaturized while suppressing deterioration of optical performance.

In the present embodiment, the urging force is generated by pulling the coil spring 109, but the urging force may be generated by compressing the coil spring 109. Further, although the sensitivity, the weight, and the intersection angle are treated equally, the coil spring may be set by weighting each value.

FIG. 5 is a schematic diagram of a liquid crystal projector IP including the lens unit LU1 of the present embodiment. The liquid crystal projector IP has a liquid crystal panel LP that produces an image to be projected and displayed. The lens unit LU1 projects the image generated by the liquid crystal panel LP to the outside.

FIG. 6 is a schematic view of an image pickup apparatus IA including the lens unit LU2 of the present embodiment. The lens unit LU2 holds the imaging optical system IOS. The camera body CB holds the image sensor IE. The lens unit LU2 may be integrally configured with the camera body CB, or may be configured to be detachably attached to the camera body CB. Further, the lens unit LU2 may hold the image pickup device IE.

The present invention includes not only an image projection device such as a liquid crystal projector, a lens barrel detachably attached to a camera body, and an optical device such as a lens-integrated camera, but also a photographing device such as a video camera or a surveillance camera, binoculars, and the like. It can also be applied to optical instruments such as observation devices.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof.

100 Lens unit 103 3rd lens barrel (1st lens barrel)
104 4th lens barrel (2nd lens barrel)
105 5th lens barrel (3rd lens barrel)
107 Coil spring (first urging means)
108C Cam Follower (1st Cam Follower)
108D Cam Follower (Second Cam Follower)
108E Cam Follower (Third Cam Follower)
109 Coil spring (second urging means)
111 Fixed cylinder 111B Straight groove 114 Zoom cam ring (cam ring)
114C cam groove (first cam groove)
114D cam groove (second cam groove)
114E cam groove (third cam groove)

Claims (8)

The first lens barrel to which the first cam follower is attached, and
A second lens barrel arranged on the main body side of the optical instrument with respect to the first lens barrel in the optical axis direction and to which a second cam follower is attached.
A third lens barrel arranged on the main body side of the optical device with respect to the second lens barrel in the optical axis direction and to which a third cam follower is attached.
The first cam follower, the first cam groove into which the second cam follower and the third cam follower are fitted, the second cam groove and the third cam groove are angled with respect to the optical axis direction. With the cam ring formed in
A fixed cylinder in which a straight groove into which the first cam follower, the second cam follower, and the third cam follower are fitted is formed along the optical axis.
A first urging means for urging the first and second lens barrels in a direction intersecting the optical axis direction, and a first urging means.
It has a second urging means for urging the second and third lens barrels in a direction intersecting the optical axis direction.
Two lens barrels corresponding to the larger spread between the first cam groove and the second cam groove and the wider spread between the second cam groove and the third cam groove are attached. Make the urging force of the first or second urging means stronger than the urging force of the first or second urging means that urges the two lens barrels corresponding to the smaller spread. A lens unit characterized by that. The spread between the second cam groove and the third cam groove is larger than the spread between the first cam groove and the second cam groove.
The lens unit according to claim 1, wherein the urging force of the second urging means is stronger than the urging force of the first urging means. The first urging means urges the second lens barrel on the side where the angle of intersection between the straight groove and the second cam groove is wide.
The second urging means according to claim 1 or 2, wherein the third lens barrel is urged on the side where the angle of intersection between the straight groove and the third cam groove is wide. Lens unit. The urging force of the first and second urging means is the sensitivity of each of the first to third lens barrels, the weight of each of the first to third lens barrels, and the straight groove and the above. The lens unit according to any one of claims 1 to 3, wherein the lens unit is set based on at least one of the angles of intersection with the first to third cam grooves. The lens unit according to any one of claims 1 to 4, wherein the urging force of the first and second urging means is stronger than the own weight of the first and third lens barrels, respectively. .. The lens unit according to any one of claims 1 to 5, wherein the sum of the urging forces of the first and second urging means is stronger than the own weight of the second lens barrel. An optical device comprising the lens unit according to any one of claims 1 to 6. The optical device according to claim 7, wherein the optical device is a projector including a liquid crystal panel that generates an image to be projected and displayed.

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