JPH0271212A - Zoom lens driving mechanism - Google Patents

Abstract

PURPOSE:To obtain a compact mechanism and to improve the reliability of whirl stop by providing a zoom cam ring, which moves first and second group lenses, and a first group driving part, which has a focus cam which moves the first group lens, together on a zoom shaft and using a guide shaft as the whirl stop of the zoom shaft. CONSTITUTION:A zoom cam ring 120 and the first group driving part are provided together on one zoom shaft 122, and a freely moving focus cam 132 is provided, and cam followers are engaged with first and second cam grooves of the cam ring 120 and the cam groove of the cam 132. Consequently, when the cam ring 120 is rotated, not only a first group lens 102 but also a second group lens 104 is moved to perform zooming. When the cam 132 is moved, only the lens 102 is moved to perform focusing. Meanwhile, a whirl stop fork 138B is so attached that it clips a guide shaft 112, and the zoom shaft 122 is not rotated. Thus, the whirl stop precision is improved with the compact mechanism.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a zoom lens drive mechanism, and more particularly to a zoom lens that performs zoom drive and focus drive of a zoom lens that is composed of a front group lens and a rear group lens. Regarding the drive mechanism.

[Conventional technology]

Generally, a zoom lens is composed of four groups: a focus lens group, a variator lens group, a convencator lens group, and a mask lens group.

Therefore, the object image passing through the zoom lens is first formed by the focus lens group, and this image is magnified and formed by the variator lens group. Furthermore, after the image point movement of the image magnified by the variator lens group is corrected by the compensator lens group, it is transferred to the surface of the imaging device as a subject image by the mask lens group, which is stopped and does not participate in zooming. is imaged.

Such a zoom lens adjusts the focus by, for example, rotating the focus ring and moving the focus lens group in the optical axis direction, and rotates the zoom ring to move the variator lens group and the compensator lens group in a fixed relationship in the optical axis direction. By moving the lens to , it is possible to change the magnification without moving the focal point.

[Problem that the invention seeks to solve]

By the way, since the above zoom lens is composed of four lens groups, the movement of the focus lens group for performing focus adjustment and the movement of the variator lens and compensator lens groups during zooming do not interfere with each other. . However, when a zoom lens consists of two groups, a front lens group and a rear group lens, only the front group lens must be moved when adjusting focus, and the front and rear group lenses must be moved simultaneously when zooming. It has been difficult to realize these movements without interfering with each other and with a simple configuration.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a zoom lens drive mechanism that can realize the drive of a zoom lens consisting of a front group lens and a rear group lens with a simple and compact mechanism. With the goal.

[Means for solving problems]

In order to achieve the above object, the present invention provides a first group lens and a second group lens forming a zoom lens, each of which is disposed movably in the optical axis direction by a guide shaft, and which is disposed parallel to the guide axis. a zoom cam ring rotatably disposed on the zoom shaft and having first and second cam grooves around the zoom cam ring; and a first group movably disposed on the zoom shaft in the axial direction. a first group driving member having a rotation preventing member that engages with the guide shaft to prevent the first group driving member from rotating in a direction around the zoom axis;
a focus cam member that moves in the zoom axis direction together with the group drive member and is movable with respect to the first group drive member, and the first group drive member is provided in the first and second cam grooves of the zoom cam ring, respectively. and engaging a cam follower provided on the second group lens, and engaging a cam follower provided on the first group lens with a cam groove formed in the focus cam member to rotate the zoom cam ring. By this, the first group lens and the second group lens are moved in the optical axis direction in a fixed relationship, and the first group lens is moved in the optical axis direction by moving the focus cam member. It is characterized by

[Effect]

According to the present invention, a zoom axis is disposed parallel to a guide axis of a zoom lens made up of a first group lens and a second group lens, a zoom cam ring is rotatably disposed on this zoom axis, and the kite axis by means of a detent member engaged with the first
The group driving member is arranged to be movable only in the zoom axis direction.

That is, a zoom cam ring and a first group driving member are provided together on one zoom axis. Furthermore, a focus cam member is provided that moves in the zoom axis direction together with the first group drive member and is movable relative to the first group drive member. and,
The first and second cam grooves of the zoom cam ring each have a first groove.
The group driving member and the cam follower provided on the second group lens are engaged with each other, and the cam follower provided on the first group lens is engaged with the cam groove of the focus cam member.

Therefore, when the zoom cam ring is rotated, the first group lens moves and the second group lens simultaneously moves via the first group driving member and the focus cam member, thereby performing zooming. Furthermore, when the focus cam member is moved, only the first lens group moves and focus adjustment is performed.

〔Example〕

Preferred embodiments of the zoom lens drive mechanism according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a perspective view of a mechanism section of a camera optical system including a zoom lens drive mechanism according to the present invention, and FIG. 2 is a perspective view of the mechanism section of FIG. 1 separated into a zoom lens section 100 and a finder section 200. It is a perspective view showing a state.

[Zoom lens drive mechanism]

First, the drive mechanism of the zoom lens will be explained. Third
The figure is a cross-sectional view of the zoom lens unit 100 shown in FIG. 2, where the upper side of the optical axis of the zoom lens shows the case where the zoom lens is located at the telephoto end, and the lower side shows the case where the zoom lens is located at the wide end. It shows the case.

FIG. 4 is an exploded perspective view of the main components of the zoom lens drive mechanism.

As shown in FIGS. 3 and 4, the front sliding frame 102A and the rear sliding frame 104A are connected to the lens barrel body 106 and the barrier 108.
The main guide bar 112 and the subordinate guide bar 114 are arranged between the main guide bar 112 and the front fixing plate 110, which are provided with a front fixing plate 110, and are slidably guided in the optical axis direction.

Here, the zoom lens is composed of two groups, a front group lens 102 and a rear group lens 104, and the front group lens 102 includes a lens 102c and a spacer ring 1 in a front lens frame 102B.
After inserting 02D, lenses 102E and 102F,
A retainer ring 102G is screwed on (see FIG. 5(A)), and the front lens frame 102B is screwed on the front sliding frame 102A.

On the other hand, in the rear group lens 104, a lens 104C is attached from the front inside the rear lens frame 104B, and the lens 104C is attached from the rear.
After inserting D, 104E, light shielding plate 104F, and lens 104G, the presser ring 104H is screwed on (see Fig. 5 (B)).
Furthermore, this rear lens frame 104B is inserted into the rear sliding frame 104A and fixed by a rear lens holding ring 104I (see FIG. 5(C)).

Next, a zoom cam ring 120 for moving the front group lens 102 and the rear group lens 104, a front group drive collar 130,
The focus cam ring 132 will be explained.

As shown in FIG. 3, the zoom cam l1120 is rotatably disposed on a zoom shaft 122 that is arranged in parallel with the main guide bar 112 and the secondary guide bar 114 of the zoom lens, and the front group drive collar 130 is also rotatably mounted on the zoom shaft 122. is slidably inserted in the axial direction.

The focus cam ring 132 is the front group drive collar 130.
It is arranged so that it can rotate freely.

That is, the E IJ song 2 is located approximately at the center of the zoom axis 122.
4A is fitted and inserted, and the spring presser washer 124B1, spring presser plate 124C, spring 124D and zoom cam ring 120 are inserted in order into the rear zoom shaft of this E IJ song 24A. .128 (see Figure 6)
.

On the other hand, a focus cam ring 132, a spring 134A, and a washer 134B are sequentially inserted into the front group drive collar 130, and the washer 134B is locked by an E-ring 134C (see FIG. 7).

That is, the focus cam ring 132 is biased by the spring 134A so as to come into contact with the side surface of the front group drive collar 130. Note that the focus cam ring 132 has gear 1.
36 are fitted.

The front group drive collar 130 equipped with the focus cam [132] is inserted into the zoom shaft 122 as shown in FIG. 8 (see FIG. 4), and then the zoom cam ring 120
An operating shaft 138 having a roller 138A and a rotation prevention fork 138B is installed in the front group drive collar 130 through the cam groove 120Δ.

In this way, the zoom shaft 122 into which the zoom cam ring 120, the front group drive collar 130, etc. are inserted is fixed at one end to the front fixing plate 110 and at the other end to the adjustment collar 140, as shown in FIG. inserted. At this time, as described above, the zoom cam ring 120 is biased by the spring 124D disposed between the zoom cam ring 120 and the zoom shaft 122 so that the rear end of the zoom cam ring 120 comes into contact with the tip of the adjustment collar 140, and the zoom shaft 122 is biased such that one end thereof comes into contact with the front fixing plate 110.

Further, the adjustment collar 140 can move in the axial direction of the zoom shaft 122 to fix the zoom cam ring 120 at any position in the axial direction of the zoom shaft 122. That is,
The adjustment collar 140 has a lens barrel main body 1 as shown in FIG.
Adjustment pin 14 through cam groove 106A formed in 06
2 is implanted, and this adjustment pin 142 is inserted into the cam groove 10.
6A, the adjustment collar 140 can be moved forward and backward in the axial direction of the zoom shaft 122. This adjustment collar 140 can be fixed at any position by tightening a set screw 144.

Now, the zoom cam ring 120 has two
Two cam grooves 120A and 120B are formed, and a roller 138A on an operating shaft 138 provided on the front group drive collar 130 is slidably engaged with the cam groove 120A as shown in FIG. A roller 105 provided on the rear sliding frame 104A is slidably engaged with the groove 120B.

Further, the anti-rotation fork 138B on the operating shaft 138 provided on the front group drive collar 130 is attached so as to sandwich the main guide bar 112, as shown in FIG. It is designed not to rotate in the direction around the shaft 122. In addition, main guide bar 1
12 is a highly reliable member, and this main guide bar 1
By using 12 as a rotation stopper, it is possible to maintain high accuracy in preventing rotation in the direction around the axis on the zoom shaft 122 of the front group drive collar 130.

On the other hand, a cam groove 132A is formed in the focus cam ring 132, as shown in FIG.
As shown in FIG. 3, a roller 103 provided on the front sliding frame 102A is slidably engaged with the roller 2A.

Therefore, when the zoom cam ring 120 is rotated, the front group drive collar 130 and the rear sliding frame 104, with the rollers 138A and 105 engaged in their cam grooves 120A and 120B, are rotated.
Δ moves in the axial direction of the zoom axis 122 with a constant relationship. That is, as described above, the front group drive collar 130 can only move in the axial direction of the zoom shaft 122 by the anti-rotation fork 138B.
0, the focus cam ring 132 and the row 10 move.
3. The front group lens 102 moves via the front sliding frame 102A, and the rear group lens 1 moves as the rear sliding frame 104A moves.
04 moves. The front group lens 102 and the rear group lens 104 that make up these zoom lenses fit into the cam grooves 120A and 1 of the zoom cam ring 120 during zooming.
20B, they move in different ways so that there is no movement of the focal point.

Here, as is clear from Fig. 3, the zoom cam ring 1
20 is formed so that a part thereof (the part where the cam groove 120A is formed) is hollow, and a part of the front group drive collar 130 and the focus cam ring 132 can enter into this hollow part 120C. ing. Further, as shown in FIG. 6, the end 120D of the zoom cam l1120 on the cam groove 120A side is cut out, so that the roller 1 engaged with the cam groove 132A of the focus cam ring 132 is cut out.
03 (FIG. 3) and the zoom cam ring 120 can be avoided.

That is, the zoom cam ring 120 configured as described above allows the length of the zoom lens drive mechanism in the zoom axis direction to be shortened.

On the other hand, when the focus cam ring 132 is rotated, the front sliding frame 1 with the roller 103 engaged with the cam groove 132A
02A, that is, the front lens group 102 is connected to the guide bar 112.1
14 in the axial direction. And this front group lens 10
Focusing is performed by movement 2.

Note that the cam groove 1 formed in the focus cam ring 132
32A is a groove linear with respect to the rotation angle, and if the rotation angle range actually used is 100 degrees, the cam groove 132A is formed over a range of 200 degrees including 50 degrees before and after the rotation angle range. has been done. The reason why the cam groove 132A is formed to extend far beyond the rotation range actually used is to perform zoom adjustment.

Generally, zoom adjustment of a zoom lens is performed so that the focal point does not shift during zooming, and this zoom adjustment is performed as follows.

That is, as shown in FIG. 3, by moving the adjustment collar 140 in the axial direction of the zoom shaft 122, the position of the zoom cam ring 120 on the zoom shaft 122 that contacts the adjustment collar 140 is adjusted.

Thereby, the entire front group lens 102 and rear group lens 104 can be moved in the optical axis direction.

On the other hand, the distance between the front group lens 102 and the rear group lens 104 can be adjusted by adjusting the rotation range of the cam groove 132A formed in the focus cam ring 132 that is actually used.
This is done by appropriately setting the reference position (home position) of the focus cam ring 132 during focus adjustment. Note that the details of setting this home position will be described later.

In Figure 3, the light passing through the zoom lens is t=”
- An image is formed on the light-receiving surface of the CCD sensor 154 via the mass fritter 150A, the low-pass filter 150B, and the shutter 152. Charges corresponding to the subject are accumulated on the light-receiving surface of the CCD sensor 154, and an electrical signal corresponding to the charge pattern is output. And this electrical signal is
The information is magnetically recorded on a video floppy (not shown).

Further, the light split by the beam splitter 150A is transmitted through automatic exposure (AE) lenses 150G, 150I,
The light is received by the AE sensor 156 via the Fresnel lens 150L. Based on the amount of light received by this AE sensor 156, the rear group lens 104 and the beam splitter 1
The aperture plate 182 disposed between the aperture plate 50A and the aperture plate 182 is rotationally controlled to an appropriate rotational position. Note that the aperture plate 182 is formed with a plurality of holes having different diameters, and the amount of incident light is controlled by selecting one of these holes.

FIG. 9 is an exploded perspective view of the prism box section in which the optical system is housed, and the beam splitter 150A is inserted from the front of the prism box 150. Note that a prism mask 150E is provided on the upper surface side of the beam splitter 150A.
is inserted, and a pressing spring 150F is inserted into the lower surface side.

Furthermore, the low-pass filter 150B is connected to the prism box 1.
50 is inserted from the rear, and the presser plates 150C and 150D
Fixed by In addition, as shown in FIG.
After being positioned, the CCD holder 158 is fixed by a presser plate 159 having a light-shielding rubber 159A, and then this CCD holder 158 is fixed to the rear of the prism box 150.

On the other hand, facing the upper surface of the beam splitter 150A, a lens 150G and a light shielding sheet 150H are arranged in order.

A lens 150■ and a lens holder 150J are inserted from above the prism box 150, and finally an AE sensor mask 150K and a Fresnel lens 150L are fixed.
The sensor frame 157 is screwed.

Next, the zoom drive unit 160 for rotating the zoom cam ring 120, the focus drive unit 170 for rotating the focus cam ring 132, the iris drive unit 180 for rotating the aperture plate 182, etc. will be described.

These drive units 160, 170, and 180 are respectively arranged around the lens barrel body 106, as shown in FIG. Note that the iris drive section 180 is not shown in FIG.

As shown in FIG. 10, the zoom drive section 160 is composed of a zoom motor (gear morph) 162, a gear train 163, gears 165, 166 on a zoom interlocking shaft 164, etc., and the output from the zoom motor 162 is The speed is decelerated through the column 163 and transmitted to the gear 165 on the zoom interlocking shaft 164. The other gear 166 on the zoom-linked shaft 164 moves the movable lens in the finder in conjunction with zooming, and its details will be described later.

The gear 165 is connected to the zoom cam ring 12 as shown in FIG.
Therefore, when the zoom motor 162 is driven, its driving force is transmitted to the gear train 1.
63, zoom cam ring 120 via gear 165.126
The zoom cam ring 120 is rotated. When the zoom cam ring 120 rotates, the front group lens 102 and the rear group lens move in the optical axis direction in a fixed relationship as described above, and zooming is performed.

Further, zoom information of the zoom lens driven as described above is detected as follows.

That is, as shown in FIGS. 11(A) and 11(B), a brush 167 is attached to the rear sliding frame 104A, and on the other hand, a rear sliding frame is mounted on the zoom code plate 168 on which this brush 167 slides. A zoom code indicating the absolute position of the frame 104A is formed. Therefore, when the brush 167 moves on the zoom code as the rear sliding frame 104A moves during zooming with the zoom lens, a code signal (zoom information) corresponding to the moving position is obtained. Note that this zoom information is used, for example, for AE system control (stroboscopic control). Further, the zoom code plate 168 has elongated holes 168A, 1
68A and 168A are formed, so that the zoom code plate 168 can be moved in the direction along the optical axis. The zoom code plate 168 is fixed with screws 169 and 169 after its position is adjusted so that desired zoom information is output when the zoom lens is moved to the telephoto end, for example.

As shown in FIG. 12, the focus drive section 170
Moke 172, gear part main plate 173A and gear part upper plate 173
It is comprised of a gear train including gears 174 and 175 between it and B, a light shielding plate 177 on the AF interlocking shaft 176, an AF drive cam 178, and the like.

The output from the ΔF moke 172 is reduced in speed and transmitted to the gear 174 via a gear train (not shown), and the output is transmitted to the gear 174.
The signal is transmitted to gear 175 that meshes with gear 74. The gear 174 is fixed to the AF interlocking shaft 176, and the gear 175 is fixed to the AF interlocking shaft 176.
is meshed with a gear 136 fixed to a focus cam ring 132, as shown in FIG.

Therefore, when the AF motor 172 is driven, its driving force is transmitted to the gear train (not shown) and the gears 174, 175, 136.
is transmitted to the focus cam ring 132 via the focus cam ring 132, and the focus cam ring 132 is rotated. When the focus cam ring 132 rotates, the front lens group 132 rotates, as described above.
2 moves in the optical axis direction, and focus adjustment is performed. The gear 175 has teeth long enough to mesh with the gear 136 even when the gear 136 fixed to the focus cam ring 132 moves in the axial direction of the zoom shaft 122 together with the front group drive collar 130 during zooming. There is.

Further, as the gear 174 rotates, the light shielding plate 177 and the AF drive cam 178 fixed to the AF interlocking shaft 176 also rotate at the same time. Here, the light shielding plate 177 and the AF drive cam 17
8, a photo ink club button and a limit switch (not shown) are provided respectively, and when the notch 177A formed in the light shielding plate 177 comes to a predetermined detection position, the photo ink club button turns ONL and limit switch. switch is AF
The drive cam 178 turns on and off. These photo ink rubber and limit switches are used to detect the home position during automatic focus adjustment.

The AF motor 172 is a pulse motor, and the focus cam ring 13 is controlled by counting the number of pulses output to the AF motor 172 from the time when the home position is detected.
The current position of 2 can be detected. Then, automatic focus adjustment is performed by measuring the distance to the subject using the distance measuring means and driving the AF motor 172 so that the rotational position of the focus cam ring 132 comes to a position corresponding to the measured distance.

Further, as shown in FIG. 13, the light shielding plate 177 and the AF drive cam 178 are inserted into the AF interlocking shaft collar 179A and locked by the E'J link 179B, and the AF interlocking shaft collar 179A is inserted into 176,
The AF drive cam 178 is fixed onto the AP interlocking shaft 176 by a screw 179C passing through the AF interlocking shaft collar 179A (FIG. 12). Note that the mounting position of the light shielding plate 177 and the like on the AF interlocking shaft 176 is, for example, the focus cam ring 132.
Adjustments are made so that home position detection is performed when is at a position corresponding to the infinity end. Further, the AF drive cam 178 moves the objective lens in the finder up and down in order to correct parallax, the details of which will be described later.

The iris drive unit 180 also serves as a barrier drive unit, and as shown in FIG.
81, an aperture plate 182 rotatably disposed on a main plate 183 having a hole 183A, an iris motor 181 and an aperture plate 1;
82, a gear train 184 provided between the barrier reducer 1
86, a drive arm 188, etc.

The iris motor 181 is configured such that output can be taken out from both ends of the drive shaft, one output is transmitted to the diaphragm plate 182 via the gear train 184, and the other output is transmitted to the drive arm 188 via the barrier reducer 186. communicated.

The center of the hole 183A of the main plate 183 coincides with the optical axis of the zoom lens.
Five holes 182A, 18 with different diameters facing the hole 183A of
2B, . . . are formed at equal pitch intervals. The iris motor 181 is controlled based on the amount of light received from the subject detected by the AE sensor 156, so that one of the holes of the diaphragm plate 182 faces the hole 183A of the main plate 183 so that the required amount of incident light is obtained. Aperture plate 18
Rotate 2. In addition, the aperture plate 1g2 has a notch 182C.
is formed, and the home position in automatic exposure control is detected by the output of a photo ink clubter (not shown) that detects this notch 182C.

On the other hand, the output of the iris motor 181 is
After being decelerated at 86, it is applied to the drive arm 188, causing the drive arm 186 to rotate.

This drive arm 186 opens and closes the barrier 108 as described later by its rotation.

Note that the present invention is not limited to the above-described embodiment, and the front and rear lenses of the front lens group 102 and the rear lens group 104 may be configured in reverse.

[Barrier opening/closing mechanism]

Next, the barrier opening/closing mechanism will be explained in detail.

FIG. 15(A) is a front view of the barrier opening/closing mechanism, and FIG. 15(B) is a bottom view including a partial cross section of FIG. 15(Δ).

As shown in these drawings, the barrier opening/closing mechanism mainly includes the barrier 108, tension spring 191, drive plate 192,
A drive arm 186 driven by a switch cam 194, a torsion spring 195, and the aforementioned iris motor 181.
It is composed of etc.

The barrier 108 is disposed on the front fixing plate 110 so as to be rotatable around a support shaft 108A, and the barrier 108 is moved in the direction in which the hole 110A formed in the front fixing plate 110 is opened by the tension spring 191, that is, in the direction in which the hole 110A formed in the front fixing plate 110 is opened. It is biased clockwise around the shaft 108A.

The drive plate 192 is fixed to a drive shaft 193 rotatably disposed on the front fixed plate 110, and the drive plate 192 has a long hole 19 that engages with a pin 108B provided on the barrier 108.
2A is formed and the pin 1 to which the driving force is transmitted.
92B is planted.

The switch cam 194 is rotatably disposed on the drive shaft 193, has a cam portion 194A for turning the limit switch 196 ON and OFF, and is provided with a pin 194B. The coil portion of the torsion spring 195 is inserted into the switch cam 194, and both ends thereof are engaged to sandwich the pins 192B and 194B.

Further, the rotation center of the drive arm 186 driven by the iris motor 181 is coaxial with the drive shaft 193 on which the switch cam 194 is disposed.
6 can come into contact with the side surface of the switch cam 194 depending on its rotational position.

Next, the operation of the barrier drive mechanism configured as described above will be explained.

FIG. 15(A) shows the barrier closed state.

In this state, the biasing force of the tension spring 191 is sequentially applied to the pin 108B on the barrier 108, the driving plate 192, and the driving plate 19.
Pin 192B on 2, torsion spring 195, switch cam 1
94 to the pin 194B on the switch cam 194.
However, since the drive arm 186 is in contact with the side surface of the switch cam 194, the rotation of the switch cam 194 is prevented, and the barrier The closed state is maintained. Also, at this time, since the required pressing force is not applied to the lever 196A of the limit switch 196 from the cam portion 194A of the switch cam 194, the limit switch 196 is in the OF position.
It is F.

From this state, when the drive arm 186 is rotated counterclockwise to the position shown in FIG.
8 is rotated clockwise by the biasing force of the tension spring 191 to be half opened, and the drive arm 186 is rotated as shown in FIG. 16(B).
When the barrier 108 is rotated counterclockwise to the position shown in , the barrier 108 is further rotated clockwise and fully opened. In the state shown in FIGS. 16(A) and 16(B), the lever 196A of the limit switch 196 is pressed by the cam portion 194A of the switch cam 194, and the limit switch 196
is ON.

When the drive arm 186 is further rotated counterclockwise from the state shown in FIG. move away from the sides. Then, automatic exposure control is performed in a predetermined area after the barrier 108 is fully opened and the drive arm 186 is separated from the side surface of the switch cam 194.

That is, as the iris motor 181 rotates to open and close the barrier 108 from the barrier closed state shown in FIG. 15(A) to the barrier open state shown in FIG. 16(B), the aperture plate 182 rotates about two revolutions. ing. Then, for example, the position where the aperture plate 182 has rotated three times is set as the home position for automatic exposure control, and exposure control is performed by controlling the rotation of the aperture plate 182 thereafter. Note that the home position is reached at the notch 18 formed in the aperture plate 182 after the output of the limit switch 196 rises from OFF to ON.
The rotation of the diaphragm plate 182 is controlled by the iris motor (pulse motor) 181 according to the exposure control from the time when the home position is detected. This is done by applying a different number of drive pulses.

On the other hand, from the state shown in FIG. 16(B), the drive arm 186
When the switch is rotated clockwise, the rotation force is sequentially applied to the pin 194B on the switch cam 194.

It is transmitted to the torsion spring 195, the pin 192B on the drive plate 192, the drive plate 192, and the pin 108B on the barrier 108,
The barrier 108 is rotated counterclockwise against the biasing force of the tension spring 191. In this way, barrier 10
8 is fully closed as shown in FIG. 15(A), the limit switch 196 goes to 0FFL and the rotation of the iris motor 181 is stopped.

Note that if the rotation of the barrier 108 is blocked by an obstacle during the closing operation of the barrier 108, the drive plate 192 stops together with the barrier 108, but the switch cam 194 continues to rotate in the clockwise direction. This allows pin 194B on switch cam 194 and pin 1 on drive plate 192 to
92B are separated from each other, and both ends of the torsion spring 195 that sandwich the pins 194B and 192B gradually open against the biasing force of the torsion spring 195. Therefore, when the obstacle is removed, the barrier 108 is instantly rotated to a position corresponding to the rotation position of the switch cam 194 by the biasing force of the torsion spring 195.

[Parallax correction mechanism and zoom finder tertiary,
The vararax correction mechanism and zoom finder will be explained. As shown in FIGS. 1 and 2, the finder section 200 is arranged above the zoom lens section 100, and the finder section 200 further includes a finder main plate section 2.
00A and a finder case section 200B above it.

The finder main plate section 200A mainly serves as a zoom drive section 160 and a focus drive section 17 of the zoom lens section 100.
It functions as a transmission means for transmitting the driving force from 0 to the finder case portion 200B.

FIG. 17 is an exploded perspective view of this finder main plate portion 200A.

In the figure, a pin 202A on the main plate 202.

An F cam 204, an F cam floor 206, and an AFJ moving lever part 220 are rotatably inserted into 202B and 202C, respectively, and a holding member 20 is inserted to prevent these from falling off.
8 is fixed to the main plate 202 by screws 210 and 210. In addition, the ΔF interlocking lever unit 220 holding member 20
A torsion spring 212 is disposed between the AF linking lever part 220 and the torsion spring 212, and the AF interlocking lever detail 220 is biased in six directions by the arrows.

Further, an F intermediate lever 216 is rotatably disposed on the main plate 202 via an F short bar shaft 214.
14 is supported by a bridge holder 218 which is fixed to the main plate 202 with screws 217 and 217.

Now, the F cam 204 is provided with a gear 204A, and this gear 204A meshes with a gear 166 on the zoom interlocking shaft 164 of the zoom drive section 160, as shown in FIG. Further, the F cam floor 206 has its lower end 206A in sliding contact with the cam surface of the F cam 204, and its upper end 206A.
6B is engaged with the lower end portion 216A of the F intermediate lever 216.

Therefore, when the F cam 204 rotates in conjunction with the zoom drive, the F cam blower 206 causes the F intermediate lever 21 to rotate.
6 will start rotating.

On the other hand, a roller 228 is located at the lower end of the AF interlocking lever detail 220.
This roller 228 is in contact with an AFF moving cam 178 on an AFF moving shaft 176 in a focus drive section 170, as shown in FIG. Therefore, when the AFF moving cam 178 of the focus drive unit 170 rotates in conjunction with automatic focusing, the AF interlocking lever detail 220 rotates, and the tip portion 220A of the AF interlocking lever detail 220 moves down the road.

Here, the details of the AF interlocking lever 220 will be explained in more detail.

As shown in FIG. 18, it has an AF interlocking lever detail 220, a finder AF interlocking lever 222, and a passive lever 224, and these levers 222 and 224 are connected by an interlocking lever collar 225 and an eccentric pin 226.

Further, the roller 22 mentioned above is attached to the lower end of the passive lever 224.
8 is attached by a roller shaft 229.

By rotating the eccentric pin 226, the passive lever 224 can be rotated slightly around the interlocking lever collar 225 relative to the bar 222 in conjunction with the finder AF. That is, the mounting angles of the finder AF interlocking lever 222 and the passive lever 224 can be finely adjusted, and by this fine adjustment, balax correction, which will be described later, is performed satisfactorily.

The finder case section 200B includes an objective lens 232 that moves up and down during balax correction, a moving lens 234 for zooming, a half lens 236, and an eyepiece 2.
a finder optical system consisting of 38, a light projection lens 250,
A distance measuring means including a light receiving lens 252 and the like is housed therein.

FIG. 19 is an exploded perspective view of the finder case 200B. The light emitting lens 250 and the light receiving lens 252 are housed on both sides of the finder case 230, and an infrared diode (not shown) is housed behind the light emitting lens 250. A light emitting frame 254 is provided on which a light receiving lens 252 is mounted, and two silicon photodiodes (SPDs) (not shown) are provided behind the light receiving lens 252. That is, the distance measuring means provided in this finder case part 200B is
It uses an active triangulation method, in which an infrared diode emits infrared light onto the subject, the infrared light reflected by the subject enters two SPDs, and the output ratio of the two SPDs determines the distance to the subject. Measure the distance.

Further, in the center of the finder case 230, an objective lens 232, a moving lens 234, and a half lens 236 are arranged in order.
, a reticle plate 237, and an eyepiece lens 238 are housed.

The objective lens 232 is movably guided in a direction (up and down) perpendicular to the finder optical axis by a moving frame 232A, and the moving frame 232A has a moving frame spring 232B for biasing the objective lens 232 downward. It is arranged.

The movable lens 234 is movably guided in the direction of the finder optical axis by its movable frame 234A, movable frame holder 234B, and the like. A pin is provided on the lower surface of the moving frame 234A, and the elongated hole 24 of the frame lever 240 is connected to the pin.
0A is engaged.

Further, the base end portion of the frame lever 240 is fixed to the rotating shaft portion of a lens lever 242, and furthermore, this lens lever 242 is biased in the six directions of arrows by a tension spring 244.

In addition, in FIG. 19, 246 is the ΔF substrate, 247 is the upper lid,
248 is a lower lid.

Now, the tip of the F intermediate lever 216 disposed on the finder main plate 20OA side can engage with a pin 242A provided on the lower surface of the lens lever 242. Therefore, when the F cam 204 rotates in conjunction with the zoom driving of the zoom lens, the lens lever 216 rotates via the F cam float 206 and the F intermediate lever 216. The rotation of the lens lever 216 causes the frame lever 240 to rotate, and the movable frame 234A1, that is, the movable lens 234, whose pin is engaged with the elongated hole 240 at the tip of the frame lever 240, moves in the direction of the finder optical axis. I can do it. Thereby, the angle of view of the finder is made to match the angle of view of the zoom lens. Note that when the zoom lens is driven to the telephoto side, the movable lens 234 moves backward, and when the zoom lens is driven to the wide side, the movable lens 234 moves backward.
moves forward.

On the other hand, the tip part 220A of the AF interlocking lever detail 220 disposed on the finder main plate part 200A side is connected to the objective lens 230A.
It is designed so that it can come into contact with the lower end of. Therefore, when the AFF moving cam 178 of the focus drive unit 170 rotates in conjunction with automatic focusing, the AF interlocking lever detail 220 rotates. Then, by rotating this AF interlocking lever detail 220, its tip 220A moves down the road, and the objective lens 23
2 is moved up and down, thereby performing vararax correction.

In addition, when the zoom lens is focused at an infinite distance, the objective lens 232 is moved from the AF interlocking lever detail 220.
is pushed up to the upper end against the biasing force of the moving frame spring 232B, and as the zoom lens focuses on the near side, the objective lens 232 is lowered.

〔Effect of the invention〕

As explained above, according to the zoom lens drive mechanism according to the present invention, the zoom axis is disposed parallel to the guide axis of the zoom lens consisting of the first group lens and the second group lens, and the first
A zoom cam ring that moves the group lens and the second group lens, and a first group drive member having a focus cam member that moves the first group lens are arranged on the zoom axis, so that the zoom drive and the zoom lens of the zoom lens are Focus drive can be realized with a simple and compact mechanism. In addition, since the guide shaft of the zoom lens is used to prevent rotation of the first group drive member disposed on the zoom axis, the reliability of the rotation prevention is high and the number of parts required for rotation prevention is minimized. It can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a mechanism section of a camera optical system including a zoom lens drive mechanism according to the present invention, and FIG. 2 is a perspective view showing a state in which the mechanism section of FIG. 1 is separated into a zoom lens section and a finder section. Figure 3 is a sectional view of the zoom lens section shown in Figure 2, Figure 4 is an exploded perspective view of the main components of the zoom lens drive mechanism, and Figures 5 (A) and (B) are the front group, respectively. An exploded perspective view of the lens and rear group lens, Figure (C) is a perspective view of the rear lens holding ring, Figure 6 is an exploded perspective view of the zoom cam ring etc. inserted through the zoom shaft, Figure 7 is the front group drive collar. , an exploded perspective view of the focus cam ring, etc., FIG. 8 is a perspective view showing how the zoom cam ring and front group drive collar are attached to the zoom axis, FIG. 9 is an exploded perspective view of the prism box section, and FIG. 10 is an exploded perspective view of the prism box section. A perspective view of the zoom drive section, FIGS. 11A and 11B are a front view and a plan view of the zoom information detection section, respectively.
The figure is a perspective view of the focus drive section, FIG. 13 is an exploded perspective view of the light shielding plate, AFF movement cam, etc. disposed on the AFF movement axis of the focus drive section, and FIG. 14 is a perspective view of the iris drive section.
Figure 15 (A) is a front view of the barrier opening/closing mechanism, and Figure 15 (B) is a front view of the barrier opening and closing mechanism.
) is a bottom view including a partial cross section of FIG. 16(A), and FIG.
) and (B) are front views of the barrier opening/closing mechanism showing the barrier half-open and fully open states, respectively, FIG. 17 is an exploded perspective view of the finder main plate, and FIG. 18 is an exploded perspective view of a part of the AF interlocking lever. FIG. 19 is an exploded perspective view of the finder case section. 102...Front group lens, 104...Rear group lens,
112...Main guide bar 114...Sub guide bar 120/zoom cam ring, 120A, 120B, 1
32A...Cam groove, 122...Zoom axis,
130: Front group drive collar 132: Focus cam ring, 138B: Anti-rotation fork.

Claims (1)

[Scope of Claims] A first group lens and a second group lens constituting a zoom lens, each of which is disposed movably in the optical axis direction by a guide shaft, and a zoom axis disposed parallel to the guide axis. , a zoom cam ring rotatably disposed on the zoom shaft and having first and second cam grooves around the zoom cam ring; and a first group driving member disposed on the zoom shaft so as to be movable in the axial direction. , a first group driving member having a rotation preventing member that engages with the guide shaft to prevent the first group driving member from rotating in a direction around the zoom axis;
a focus cam member that moves in the zoom axis direction together with the first group drive member and is movable with respect to the first group drive member, the first group being disposed in the first and second cam grooves of the zoom cam ring, respectively; A driving member and a cam follower provided on the second group lens are engaged, and a cam follower provided on the first group lens is engaged with a cam groove formed in the focus cam member, and the zoom cam ring is rotated. By rotating the
The first group lens and the second group lens are moved in the optical axis direction in a fixed relationship, and the first group lens is moved in the optical axis direction by moving the focus cam member. A zoom lens drive mechanism.