JP3240542B2 - Zoom lens focus adjustment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for adjusting the focus of a zoom lens provided in an optical apparatus such as a film-loaded camera, an electronic still camera, a video camera, and a copy machine.

[0002]

2. Description of the Related Art A zoom lens provided in a camera has a cam frame having an elongated cam hole extending along the periphery thereof, and a cam follower projecting into the cam hole. In many cases, a plurality of movable frames are provided, and the cam frames are rotated to move each movable frame, and the photographing lens is displaced in the optical axis direction to change the magnification.

However, since such a zoom lens uses a cam frame that requires high precision in design and production, it becomes a costly product. Therefore, today, a zoom lens that does not use any cam frame is used. Murrens are being developed.

FIG. 20A is a simplified view of a zoom lens which is driven by a motor without using a cam frame. As shown, a first moving frame 13 is provided in the fixed frame 11 so as to move along the optical axis 12.

A shutter mounting frame 14 is fixed to the first moving frame 13, and a front group lens 15 is mounted on the shutter mounting frame 14. Note that shutter blades are provided on the back side of the shutter mounting frame 14.

The first moving frame 13 is connected to a driving ring 16 and is pushed out and pulled back by the driving ring 16. That is, the male helicoid screw provided outside the drive ring 16 is screwed into the female helicoid screw on the inner surface of the fixed frame 11, and the drive ring 16 is
It is rotationally driven by the motor 17 to move in the optical axis direction,
The first moving frame 13 is moved forward and backward without rotating.

A rear group lens 18 is provided inside the first moving frame 13.
The second moving frame 19 to which is attached is provided. This second
A part of the moving frame 19 is screwed to a lead screw 20 supported by the first moving frame 13, and the lead screw 20 is driven to rotate by a second motor 21 disposed on the shutter mounting frame 14. As a result, the second moving frame 19 is
Move along.

FIG. 20A shows a state in which the zoom lens is retracted in the camera. When the main switch is turned on in this retracted state, first, the first motor 17 is driven to rotate in one direction. The ring 16 is moved forward while rotating. Therefore, the first moving frame 13 is extended to the photographing position shown in FIG.

When the first moving frame 13 moves to this photographing position, the first motor 17 is stopped and the second motor 21 is driven to rotate by the detection signal. As a result, the second
The moving frame 19 moves backward as shown in FIG.
The shooting state of E is set.

When photographing in the WIDE state, focusing is performed by rotating the first motor 17 again according to the release. That is, by the movement of the first moving frame 13, both the front group lens 15 and the rear group lens 18 fluctuate to perform focusing.

In the zooming, the first motor 17 is driven to rotate, the first moving frame 13 and the second moving frame 19 are both extended, and then the second motor 21 is driven to rotate so that the second motor 21 rotates. Only the moving frame 19 is moved.

For example, when the WIDE end of FIG.
Then, the front group lens 15 and the rear group lens 18 advance together, and at the TELE end, the state shown in FIG. Thereafter, the second motor 21 is driven to rotate, and FIG.
As shown in (B), the rear lens group 18 moves forward and TELE
Shooting state.

After zooming in this manner, the first mode
Focusing is performed by driving the rotation of the heater 17 in accordance with the release. However, when the distance measurement is performed at a shorter distance than the closest distance, the second mode is operated in response to the release operation.
The rear group lens 18 is driven to rotate and the rear lens group 18 is displaced to a predetermined position to perform tele-macro focusing.

The zoom lens described above has already been applied for a patent by the present applicant as Japanese Patent Application No. 358015/1991.

[0015]

In the above-mentioned conventional zoom lens, the displacement of the flange back is adjusted by inserting a washer between the lens barrel and the camera body. Measure the flange back with the washer in between, and if the flange back is still misaligned as a result of the measurement, the lens barrel must be removed and another washer must be sandwiched in order to perform the adjustment work. Had become.

Further, since the adjustment by the adjusting means is limited by the minimum thickness of the washer, it cannot be adjusted for a deviation of about 0.02 mm. In addition, flange back adjustment is performed by displacing the mounting position of the lens barrel with a cam or a screw. However, this adjustment means requires a skill and requires a long time for the adjustment work. There's a problem.

The shift is adjusted by adjusting the distance between the front lens group 15 and the rear lens group 18. For example, the adjustment is mechanically performed by loosening the mounting screw of the front lens group 15, moving the front lens group 15 in the optical axis direction with respect to the rear lens group 18, and then tightening the mounting screw. In addition, this shift adjustment is performed by changing between lens groups, and
It is performed so that the flange back at the IDE end is the same.

Accordingly, the shift adjustment performed in this manner involves the work of loosening and tightening the mounting screws, which makes automation difficult. This will increase costs. In addition, in the case of mechanically adjusting, there is a problem that, in addition to an operation requiring skill, an adjustment operation takes time. In addition, it was not possible to adjust the shift shift in the middle of zooming.

FIG. 22 is a focus curve showing the adjustment of the flange back and the shift performed for one zoom lens of a conventional example. In this figure, 22A indicates a focus curve before adjustment, 22B indicates a focus curve after adjustment, 22C indicates a reference flange back, and 22D indicates an allowable range. In the case of such a zoom lens, the shift amount 22F is adjusted by the flange back adjustment, and the shift amount 22S is adjusted by the shift adjustment.
Are respectively corrected. However, even with such adjustment, a large shift shift remains in the middle of the zoom position.

FIG. 23 is a focus curve showing the adjustment of the flange back and shift performed for another zoom lens. In this figure, 23A is the focus curve before adjustment, 2
3B is a focus curve after adjustment, 23C is a reference flange back, 23D is an allowable range, 23F is a displacement of the flange back, and 23S is a displacement of the shift. In the case of such a zoom lens, it can be adjusted within an allowable range, but a slight shift shift remains in the middle of the zoom position.

In view of the above circumstances, the present invention measures in advance the shift between the flange back and the shift, corrects the lens movement performed by zooming and focusing based on the measured value, and performs the shift of the flange back and the shift. It is an object of the present invention to develop a zoom lens focus adjustment apparatus that automatically adjusts the zoom lens.

[0022]

According to the present invention, at least two or more lens units that move during zooming and at least the same number of lens units as the number of moving lens units are provided.
And position detecting means provided for each lens group to detect the position of the lens group by code detection and counting of encoder pulses. Each motor is controlled in accordance with the detection of the position detecting means. In a zoom lens having a configuration in which zooming and focusing are performed, a correction amount of flange back and shift of the lens is measured in advance, and the memory means for storing the correction amount as data, and the most repetitive operation of the lens.
In the zooming position where projection is small, the above-mentioned memory means is used.
Lens movement amount for zooming according to the correction data
To correct the shift, and move the lens for focusing.
To compensate for flange back, and other zooming positions.
In accordance with the correction data of the memory means described above,
And change the lens movement amount for zooming and flange back.
Correct and shift by changing the amount of lens movement for focusing
The present invention proposes a zoom lens focus adjusting device comprising a motor control means for correcting .

[0023]

The zooming and focusing are performed, and the amount of shift between the flange back and the shift of the lens at the zooming position is measured by an adjuster in advance, and the measured value is stored in the memory means as correction data. The correction de read from the storage means to the detection signal of the position detecting means - data signal is added,'s I was to these signals - zooming and follower - Kashingu rows of Umo - controls the data, most of the lens
In the zooming position where the extension is small, the zooming
Shift correction by changing the lens movement amount, and focus
The amount of lens movement to compensate for flange back, and
At other zooming positions, the zoom lens movement amount
Change and correct flange back, focusing lens
The shift is corrected by changing the amount of movement, and the amount of shift between the flange back and the shift is measured again.

This measured value is stored in the memory means as correction data. Subsequently, in the same manner as described above, the mode is changed according to the detection signal of the position detecting means and the correction data of the memory means.
Data, zooming and focusing are performed, and the amount of deviation between the flange back and the shift is measured. As a result of this measurement, if the flange back and the shift have been sufficiently corrected, the camera is removed from the adjusting device while the stored contents of the memory means are kept, and the adjustment of the flange back and the shift is completed. If the correction is insufficient, the displacement between the flange back and the shift is repeatedly measured in the same manner as described above, and the correction data is obtained.
The data is stored in the memory means, and the adjustment is completed when the correction is sufficiently made.

The above-described adjustment of the flange back and the shift can be performed by electrical information communication between the camera and the adjuster, so that the adjustment operation is simplified.
The size of the adjusting machine is not increased, and a highly accurate adjustment result can be obtained.

[0026]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view of a lens barrel of a zoom lens provided in a camera having a finder optical system having a configuration different from that of a photographing lens, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. FIG. 4 is a cross-sectional view taken along line CC of FIG. 1, and FIG. 5 is an end view cut along line DD of FIG. The lens barrel is configured to be housed in the camera body. In these drawings, 31 is a fixed frame, 32 is a first moving frame, 33 is a second moving frame, 34 is a first motor, and 35 is a second motor.

The fixing frame 31 is a cylindrical frame, and a flange 31a provided at the rear end thereof is fixed to the camera body. As can be seen from FIGS. 1 and 2, a helicoid screw (female) 31b is provided on the inner surface of the fixed frame 31, and a drive ring 36 provided inside the rear of the fixed frame 31 is screwed to the helicoid screw 31b. are doing.

That is, the drive ring 36 is provided with a helicoid screw (male) 36a around its outer periphery, and this helicoid screw 36a is screwed to the helicoid screw 31b of the fixed frame 31. The drive ring 36 has a gear 36b engraved around its front outer periphery (the outer periphery on the right end side in FIG. 2), and the gear 36b is rotated in conjunction with an output gear described later.

The driving ring 36 is connected to the first moving frame 32 by a friction spring 37. That is, the other end bent portion of the friction spring 37 having one end fixed to the locking projection 32 a of the first moving frame 32 is pressed against the rear surface of the drive ring 36. With this connection, the drive ring 36 that rotates according to the helicoid screw advances and retreats the first moving frame 32 that moves without rotating. The friction springs 37 are provided at four locations above and below the drive ring 36 (FIG. 1). Also, this friction spring 37 is
Although formed separately from the moving frame 32, it can be formed integrally with the first moving frame 32.

On the other hand, on the inner surface of the fixed frame 31, key grooves 31c linearly provided in the front-rear direction are respectively provided at three equally spaced positions, and each key groove 31c provided around the rear end of the first movable frame 32 Key
32b protrudes into these key grooves 31c.

The first moving frame 32 is a circular frame which is slightly smaller in diameter than the fixed frame 31 and is provided inside the fixed frame 31.
b is guided by the key groove 31c and moves in the optical axis direction (left and right direction in FIG. 2) without rotating. In other words, the drive ring 36 is rotated by the helicoid screws 31b and 36a and is moved in the optical axis direction while being pulled and not rotated.

The drive ring 36, as detailed in FIG.
The first motor 34 is rotationally driven by an interlocking mechanism including an output gear 38, a reduction gear 39, a long gear 40, and a moving gear 41. The first motor 34 is a DC motor, which is mounted on a fixed plate 42 provided on the fixed frame 31 and is controlled by a pulse using a photo interrupter 43. Note that 43
a indicates an encoder.

A reduction gear 39 linked to the output gear 38 and a long gear 40 linked to the reduction gear 39 are supported by a fixed frame 31. Further, a moving gear 41 interlocked with the long gear 40 is supported by a bearing upright portion 32c provided on the first moving frame 32 so that the gear 41 meshes with a gear 36b of the drive ring 36. .

By this interlocking mechanism, the rotational driving force of the first motor 34 is transmitted to the moving gear 41, and the moving gear 41
As a result, the drive ring 36 rotates. Therefore, the drive ring 36 moves according to the helicoid screws 31b and 36a, and moves the first moving frame 32 in the optical axis direction. At this time, the moving gear 41 moves along the long gear 40.

A shutter mounting frame 44 is screwed to the first moving frame 32, and a front lens 45 is supported by a cylindrical portion 44a of the shutter mounting frame 44. Near the rear side, a shutter blade 46 is provided together with a shutter blade holder. The shutter blade 46 is a motor disposed around the outside of the cylindrical portion 44a.
The opening / closing operation is performed in conjunction with the data drive source 47.

The cylindrical portion 44a of the shutter mounting frame 44
Around the outside, a second mode for driving the second moving frame 33 to move.
And an interlocking mechanism therefor. This interlocking mechanism
As shown in FIGS. 1 and 4, the output gear 4 of the second motor 35 is used.
8, a reduction gear 49 to 52, an interlocking gear 53 fixed to the lead screw 54, and a cylindrical screw (female) 55 fixed to the rising portion 33a of the second moving frame 33.

The second motor 35 is a DC motor.
As with the motor 34, pulse control is performed using a photo interrupter and an encoder. The interlocking gear 53 is a reduction gear 5 at the end.
It rotates in conjunction with 2. And this interlocking gear 53
The upright portion 33 of the shutter mounting frame 44 and the second moving frame 33
a that is pulled out backward (leftward in FIG. 4) through
It is fixed to one end of the screw 54.

The lead screw 54 is arranged so that the interlocking gear 53 is pressed against the shutter frame 44.
Are urged by the holding plate 58. Also,
A cylindrical screw 55 is screwed into the lead screw 54. The cylindrical screw 55 is screwed by the rotation of the lead screw 54 to move the second moving frame 33 in the optical axis direction (FIG. 4). Left and right directions).

The second moving frame 33 is a cylindrical frame movable within the first moving frame 32, and supports a rear lens group 56. As shown in FIG. 5, the second moving frame 33 is guided by a guide shaft 57 provided on the first moving frame 32 and moves in the optical axis direction without rotating.

That is, the second movable frame 33 is provided with a protruding arm 33b which protrudes forward (to the right in FIG. 5) through the notch 44b of the shutter mounting frame 44.
The guide shaft 57 is slidably passed through shaft holes formed in the upright pieces 33c and 33d of FIG. The guide shaft 57
Are supported by shaft stoppers 32d and 32e protruding from the front and rear ends of the first moving frame 32 into the frame.

On the other hand, the fixed frame 31 and the first moving frame 32 are provided with first code detecting means as shown in FIGS. The first code detecting means mounts a first code board 59 so as to cover a through hole 31d provided on the side surface of the fixed frame 31, and the first code board 59 is mounted on the first moving frame 32. A first code brush 60 that slides on the printed circuit board 59 is attached. The first code detecting means reads the code and detects the relative position between the fixed frame 31 and the first moving frame 32.

FIG. 6 shows the first code board 59.
a, 59b, 59c, 59d are the respective code substrates (59
a is ground), ZC1 to ZC7 are zoom code, ZP
1 to ZP6 are zoom positions, HP1 to HP6 are zoom positions.
The home positions corresponding to the front group lens 45 (first moving frame) when the camera is trimmed are shown. In addition, HP
0 is a home position corresponding to the front lens group 45 when the first moving frame 32 is stored in the camera body. In this case, the zoom code is ZC0 and the zoom position is ZC0.
It is P0.

The first moving frame 32 and the second moving frame 33 are provided with a second code detecting means as shown in FIGS. The second code detecting means includes a second code brush 61 mounted on the projecting plate portion 44c of the shutter mounting frame 44.
And attached to the protruding arm 33b of the second moving frame 33,
Second code board 62 in which the brush 61 slides.
To detect the relative position between the first moving frame 32 and the second moving frame 33.

FIG. 7 shows the second code board 62,
HP6 is a home position corresponding to the rear lens group 56 (second moving frame 33) when zooming, and HP0 is a rear lens group 56 when the lens barrel is housed in the camera.
The home position corresponding to, and A to D are divided cores.
Is shown. FIG. 8 shows the second code board 62 similarly to FIG. 7, but this figure shows the moving direction of the rear lens group 56 by focusing.

FIG. 9 is a simplified block diagram showing a drive control circuit for the above-mentioned lens barrel. As shown, a controller 63 inputs ON / OFF signals of a main switch 64, a WIDE switch 65, and a TELE switch 66, and receives a first motor 34 (hereinafter referred to as DC1) and a second motor.
Drive 35 (hereinafter referred to as DC2). As a result, the front group lens 45 and the rear group lens 56 move to perform zooming.

When the shutter switch 67 is operated after the zooming is completed, the controller 63 controls the driving of the DC1 or DC2 again to perform focusing. Further, the controller 63 operates the shutter sequence circuit 68 after the focusing is completed to operate the shutter.

The amount of shift between the flange back of the lens barrel and the shift is measured by an adjuster, and the measured value is used as correction data for the shift as an EEPROM as memory means.
In advance. The adjustment of the flange back and the shift is performed as follows.

A. Adjustment of Flange Back At the zoom position ZP1 (WIDE end), the number of pulses (the number of encoder pulses) generated by the rotation drive of the DC1 during the focusing operation is corrected by correction data read from the EEPROM 70. In the other zoom positions ZP2 to ZP6, the number of pulses generated by the rotation drive of DC1 during the zooming operation is EE.
The correction is performed by the correction data of the PROM 70.

B. Shift Adjustment The number of pulses generated by the rotation drive of the DC2 in the EEPROM 70 during the zoom operation of the zoom position ZP1 (WIDE end) and the focusing operation of the zoom position ZP6 (TELE end) are stored in the EEPROM 70. The correction is performed using the correction data. In this case, the zoom positions ZP1, ZP
The same pulse number correction is performed in P6. The shift correction in the middle of the zoom (zoom positions ZP2 to ZP5) is performed by correcting the number of pulses generated by the rotation driving of the DC2 during the focusing operation by using correction data of the EEPROM 70.

FIG. 1 shows the operation of the controller 63.
The operation of the above-mentioned lens barrel will be described in detail with reference to the flowcharts of FIGS. The lens barrel described above is housed in the camera by turning off the main switch 64. In this housed state, the first code brush 60 contacts the position of HP0 on the first code board 59, and the second The code brush 61 is located on the second code board 62 at B,
Contacting either C or D.

(1) Main switch ON The main switch 64 in a state where the lens barrel is housed.
Is turned on, the ZCO signal is input to the controller 63 from the first code detection means (59, 60), and the controller operates as shown in the flowchart of FIG. (See Fig. 6)

That is, when the main switch 64 is turned on, the controller 63 drives and controls the DC1 to the TELE side in response to the ZC0 signal. (FIG. 10, step ST1
00, ST101) Therefore, the drive ring 36 rotates and the first moving frame 32
From the storage position (HP0).

When the first moving frame 32 advances to the TELE side, the first code detecting means (59, 60) sets the code ZC.
The signal is switched from 0 to ZC1, and the controller 63 starts counting encoder pulses from the time when the ZC1 signal is input. (FIG. 10, Steps ST103 and ST104) The encoder pulse is output by the photointerrupter 43 provided in the DC1.

By counting the encoder pulses, it is determined whether or not the count has exceeded the number of addition / subtraction pulses between the number of set pulses at the WIDE end and the number of shift correction pulses.
When this number of pulses has elapsed, controller 63 sets DC1
Stop control. The shift correction pulse is stored in the EEPROM 70
Is obtained by performing pulse conversion on the WIDE end shift correction data read out. (FIG. 10, steps ST104, ST10
5)

When the DC1 stops, the first code brush 60 moves to the position HP of the first code board 59.
1 and the front group lens 45
This means that it has been fed out to the E end.

The controller 63 controls the drive of the DC2 immediately after stopping the DC1. (FIG. 10, step S
T106) In this case, the DC2 is driven to the WIDE side, and the rotation of the lead screw 54 moves the second moving frame 33 toward the WIDE side. As a result, the second code brush 61 advances toward the code A from any one of the codes B, C, and D on the second code board 62.

By this operation, the second code detecting means (6
When (1, 62) switches from code B to A, the controller 63 recognizes the input of the code A signal and counts encoder pulses from this point. (FIG. 10, steps ST107 and ST108) The encoder pulse is output from an autointerrupter linked to DC2.

When the pulse count exceeds the number of pulses obtained by adding / subtracting the preset number of WIDE-end pulses and the number of WIDE-end shift correction pulses, the control is started.
The DC 63 is controlled to be stopped by the controller 63. The shift correction pulse is obtained by converting the shift correction data read from the EEPROM 70 into a pulse. (FIG. 10, Steps ST109 and ST110) When the DC2 stops in this way, the second code brush 61 contacts the position of the position HP1 on the second code board 62, and the WIDE of the rear group lens 56. Move to the end.

Thus, the main switch 64 is turned on.
Then, the lens barrel is extended from the storage position to the WIDE end, and a photographing state is enabled.

Next, the zooming operation will be described.
The zooming is performed by operating the WIDE switch 65 and the TELE switch 66. By operating these switches 65 and 66, first, the DC1 is driven and controlled.
The zooming operation is performed according to the flowchart shown in FIG.

(2) Zooming by DC1 When the TELE switch 66 is turned on with the lens barrel extended to the WIDE end as described above, the controller 63 which has input the ON signal moves DC1 to the TELE side. Drive control. (FIG. 11, steps ST200 to ST20)
3) Therefore, the first moving frame 32 advances, and the front group lens 45 moves to the TELE side. In this case, the second moving frame 3
Since 3 advances together with the first moving frame 32, both the front group lens 45 and the rear group lens 56 move toward the TELE side.

When the tele switch 66 is continuously operated until the tele end is reached, the first code detecting means (5)
The controller 63 determines whether or not (9, 60) detected the code ZC6 immediately before the TELE end code ZC7. (FIG. 11, steps ST204, ST20
5) That is, when the first code brush 60 comes into contact with the code ZC6 of the first code board 59, the controller 63 recognizes this code ZC6 (current code Z), and And the first
The encoder pulse is counted from the time when the code brush 60 switches from the code ZC6 to the code ZC7. (FIG. 11,
Steps ST206 to ST208)

When the count of the encoder pulse exceeds the designated number of pulses, the DC1 is controlled to stop. (FIG. 11, steps ST209 and ST210) The designated pulse number at this time is the number of addition / subtraction pulses between the TELE end set pulse number and the converted pulse number of the flange back correction data read from the EEPROM 70. At this time, the first code brush 60 is moved to the first code board 5.
The first moving frame 32 advances so as to come into contact with the position HP6 at position 9, and the front group lens 45 moves to the TELE end. After stopping the DC1, the controller 63 immediately shifts to the drive control of the DC2. (FIG. 11, step ST21
1) The driving of DC2 will be described later.

If the operation of the TELE switch 66 is released before reaching the TELE end, the switch 66
The controller 63 recognizes the zoom code (current code Z) at the time of FF. (FIG. 11, step S
T204, ST206) After that, steps ST207 to ST207 are performed as described above.
Operation 211 is performed.

For example, when the zoom position ZP3 is
Assuming that the operation of the E switch 66 has been released, the controller 63 recognizes the code ZC4 as the current code Z, and subsequently, the code which is one TELE side from the code ZC4. The counting of the encoder pulse is started from the time when the ZC5 is recognized. (FIG. 11, step ST20
4, ST206 to ST208)

When the count of the encoder pulse has exceeded the designated number of pulses, DC1 is stopped, and the operation shifts to DC2 drive control. (FIG. 11, steps ST209 to ST2)
11) In this case, the designated pulse number is the number of addition / subtraction pulses of the set pulse number of the zoom position ZP4 and the converted pulse number of the flange back correction data read from the EEPROM 70. At this time, the first code brush 60 is
The front group lens 45 is brought out to the zoom position ZP4 by contacting the position of the position HP4 of the code board 59.

On the other hand, when the WIDE switch 65 is operated, the controller 63 drives and controls the DC1 to the WIDE side unless the lens barrel is at the WIDE end. (Figure 1
1. Steps ST212 and ST213) Then, the operation of the WIDE switch 65 is continued and the WIDE switch 65 is operated.
When zooming to the end, the controller 63 controls the WI
An encoder pulse is counted from the time when the DE end code ZC1 is recognized, and when the pulse count exceeds a designated number of pulses, DC1 is stopped, and then, the drive control of DC2 is started. The designated pulse number at this time is WIDE
This is the number of addition / subtraction pulses between the number of set pulses at the end and the number of converted pulses of WIDE end shift correction data read from the EEPROM 70. (FIG. 11, steps ST214 to ST214
T219) In this case, the first code brush 60 is connected to the first code board 5.
9 comes into contact with the position HP1 and the front group lens 45
Pulled back to DE end.

If the operation of the WIDE switch 65 is released before the lens barrel reaches the WIDE end, the controller 63 recognizes the current code Y at the time when the operation is released. It is determined when the current code Y has proceeded to one WIDE-side code, and from this time the encoder pulse is counted. (FIG. 11, step ST21
4, ST220 to ST222)

When the pulse count exceeds the preset number of offset pulses, the DC1 is stopped and the above-described steps ST204, ST205 to ST21 are performed.
Move on to operation 1. That is, when the number of offset pulses has elapsed, the DC1 is temporarily stopped, and the DC1 is drive-controlled to the TELE side. Then, the current code Z at the time when the DC1 starts driving is recognized, and the encoder pulse is counted from the time when the code Z shifts to the code on the TELE side by one,
When this pulse count exceeds the designated number of pulses, D
C1 is stopped, and then the operation shifts to DC2 drive control. The designated pulse number is the number of addition / subtraction pulses between the set pulse number and the converted pulse number of the flange back correction data as described above.

The above-described zooming operation will be specifically described with reference to FIG. For example, when the operation of the WIDE switch 65 is released, the first code brush 60 moves to the code ZC.
Assuming that the position is a in FIG.
When the brush 60 slides to the WIDE side and moves to the code ZC3, an encoder pulse is counted. Then, at the position b of the code ZC3 where the pulse count exceeds the number of offset pulses, DC
1 is temporarily stopped.

Subsequently, the DC1 is driven and controlled to the TELE side, the controller 63 recognizes the code ZC3, and the encoder pulse starts from the time when the first code brush 60 enters the code ZC4. Count. Then, when the pulse count exceeds the designated number of pulses, DC1 is stopped. The designated number of pulses is the zoom position Z
This is the number of addition / subtraction pulses between the set pulse number of P3 and the converted pulse number of the flange back correction data. At this time,
The first code brush 60 contacts the position of the position HP3, and the front group lens 45 is pulled back to the zoom position ZP3.

When the lens barrel is at the TELE end, TE
If the LE switch 66 is operated, and the WIDE switch 65 is operated while it is at the WIDE end, the controller 63 immediately recognizes the TELE end code ZC7 or the WIDE end code ZC1. -No ming operation is performed. (FIG. 11, steps ST202, ST2
12)

After the front group lens 45 is moved to the respective zoom positions by the driving of DC1 as described above, D
The drive of C2 is controlled, and the rear group lens 56 moves to each zooming position according to a flowchart shown in FIG.

(3) Zooming by DC2 In this operation, the controller 63 sets the front group lens 45 to W
It is determined whether or not it is at the IDE end. (FIG. 12, step ST300) If it is at the WIDE end, it is determined whether or not the current code is A (FIG. 7). (FIG. 12, step ST308) At this time, the second code brush 61 is moved to the second code board 62.
If the code A is currently set to A, the DC2 is driven to rotate toward the TELE side, and when the code B is switched, the encoder pulse is counted. (Figure 1
2. Steps ST308 to ST311)

Subsequently, when the pulse count has exceeded the number of offset pulses, the DC2 is temporarily stopped, and then the DC2 is rotationally driven to the WIDE side to reach the target code (code A in this case). Counts the encoder pulse when
When the count exceeds the designated number of pulses, DC2 is stopped. The designated number of pulses at this time is the number of set pulses at the WIDE end. (FIG. 12, step ST31)
2, ST313, ST302 to ST305) Note that this operation is the same as the one-sided pulse control shown in FIG. By this operation, the second code brush 61 comes into contact with the position HP1 of the second code board 62, and the rear lens group 56 moves to the zoom position at the WIDE end.

When the front lens 45 is located at the WIDE end,
When the code brush 61 is not on the code A of the second code board 62, that is, when it is in contact with any of the codes B, C, and D, the DC2 is driven and controlled to the WIDE side. The encoder pulse is counted from the point when the target code A is switched, and the second code brush 61 contacts the position HP1, and the rear lens group 56
Move to E end. (FIG. 12, steps ST308 and ST308)
302 to ST305)

When the DC1 is stopped and the front lens group 45 is not at the WIDE end, the current code is compared with the target code. (FIG. 12, steps ST300, ST30
1) Codes A, B, C, and D are weighted, and D> C
>B> A.

That is, if the target code for moving the rear lens group 56 is smaller than the current code (FIG. 7) at the time of the drive control of the DC2, the DC2 is driven and controlled to the WIDE side, and the target code is controlled. The encoder pulse is counted when the operation proceeds to the first mode. Then, the DC2 is stopped when the pulse count has exceeded the designated number of pulses. (FIG. 12, steps ST301 to ST305)

For example, if the current code is B and the target code is
If the code is A, the DC2 is stopped when the encoder pulse counted from the switching point between the codes A and B has passed the designated number of pulses.
Is reached at the position HP1 or HP4, the DC2 is stopped, and the rear lens group 56 moves to the zoom position of the zoom position ZP1 or ZP4. The designated number of pulses is the zoom position ZP1 or ZP1.
4 is the set pulse number.

If the target code is larger than the current code, the DC2 is driven and controlled to the TELE side, and when the target code is reached, the encoder pulse is counted. To move. (FIG. 12, step S
(T306, ST307, ST303 to ST305) This operation is for the case where the target codes required for zooming are B, C, and D, assuming that the current code is A.

When shifting to driving of DC2, if the current code and the target code are the same, DC2 is kept stopped. (FIG. 12, steps ST301, ST30
6) For example, when the front lens 45 is moved to the zoom position ZP4, if the current code is A, the current
Since both the code and the target code are A, the DC2 is not driven.

At this time, the focusing operation (DC
2 drive) to move the rear lens group 56 to a position corresponding to the position HP4. Positions HP2 and HP5
Is the current code and the target code, and also when the positions HP3 and HP6 are the current code and the target code, the rear group lens 56 is similarly moved by the focusing operation.

(4) Focusing After the zooming as described above, the shutter switch 6
7 is operated, focusing is performed according to the flowcharts of FIGS. This shutter switch 67 is linked to a shutter button. The small circles 69a and 69b in FIGS. 13 and 14 indicate connectors.

For focusing, the drive control of DC1 is performed when the lens barrel is at the WIDE end, and the drive control of DC2 is performed when the lens barrel is at a position zoomed from the WIDE end. If the lens barrel is at the WIDE end, DC1
Is turned on to the TELE side to recognize one TELE side code, that is, code ZC2, and count encoder pulses from this point. (FIG. 13, FIG. 14, step S
T400, ST416 to ST418)

When the pulse count exceeds the number of pulses obtained by adding / subtracting the number of automatic ranging signal pulses (AF pulses) and the number of flange back correction pulses, DC1 is stopped. Note that the flange back correction pulse is stored in the EEPROM 7
It is obtained by performing pulse conversion on the flange back correction data read from 0. (FIG. 14, steps ST419, ST
420) In this focusing operation, the front group lens 45 and the rear group lens 56 are extended integrally to control focusing. Subsequently, the shutter is opened and closed by the shutter sequence circuit 68. (FIG. 14, step ST421).

After the shutter operation, the DC1 is driven and controlled to the WIDE side, an encoder pulse is counted from the time when the WIDE end code ZD1 is recognized, and the DC1 is stopped when the pulse count exceeds the designated number of pulses. (Figure 1
4. Steps ST422 to ST426) At this time, the first code brush 60 is moved to the first code board 59.
And the lens barrel is in contact with the position HP1.
It returns to the zoom position ZP1 at the DE end.

If the lens barrel is zoomed to a position other than the WIDE end, the zoom position ZP2 or ZP3
Or other zoom positions ZP4, Z
Judgment is made separately based on whether it is P5 or ZP6, and the drive of DC2 is controlled. (FIG. 13, steps ST400, ST40
1)

When the zoom position is ZP2 or ZP3, DC2 is driven and controlled to the WIDE side, and encoder pulses are counted from the time when the target code is reached. The pulse count is determined by the number of AF pulses and the number of shift correction pulses. DC2 is stopped when the number of pulses obtained by adding and subtracting has elapsed. The shift correction pulse is stored in the Z stored in the EEPROM 70.
It is obtained by pulse-shifting the P2 and ZP3 shift correction data. (FIG. 13, steps ST402 to ST407)

For example, if the lens barrel is in the zoom position Z
In the case of P2, as shown in FIG.
By controlling the drive to the E side, the second code brush 61 is controlled.
The encoder pulse is counted from the point when the control signal reaches the switching point of code A or B. When the pulse count exceeds the number of addition / subtraction pulses of the number of AF pulses and the number of shift correction pulses, DC2 is stopped and focus control is performed. . When the lens barrel is at the zoom position ZP3, encoder pulses are counted from the point of switching of the codes B and C, and the same focusing control is performed.

The lens barrel is in the zoom position ZP4 to ZP.
If any of P6, DC2 is TELE
Side, and when the target code is reached, an encoder pulse is counted. And the pulse count is A
When the number of addition / subtraction pulses between the number of F pulses and the number of shift correction pulses elapses, DC2 is stopped and focus control is performed. The shift correction pulse is stored in the ZP stored in the EEPROM 70.
4 to ZP6 are obtained by pulse conversion of shift correction data. (FIG. 13, steps ST403 to ST407)

For example, if the lens barrel is in the zoom position Z
If it is at P4, as shown in FIG. 8, encoder pulses are counted from the switching point of codes A and B, and the pulse count passes the number of addition / subtraction pulses between the number of AF pulses and the number of shift correction pulses. DC2 is stopped and focus control is performed. The lens barrel has a zoom position ZP5
Or when in ZP6, code B, C or C, D
The encoder pulse is counted from the switching point of
Focus control is performed in the same manner as described above.

After the above focusing, the shutter
The shutter is opened and closed by the operation of the cans circuit 68, and subsequently, control is performed to return the rear lens group 56 to the original zoom position. (FIG. 13, step ST408)

In this return control, the zoom position is divided into the zoom position ZP2 or ZP3 and the other zoom positions in the same manner as described above. When focusing at the zoom position ZP2 or ZP3, DC2 is shifted to the TELE side. At the time of focusing at other zoom positions, the DC2 is driven and controlled to the WIDE side. (FIG. 13, step ST409,
ST411) Then, the encoder pulse is counted when each target code is reached, and the DC2 is stopped when the pulse count exceeds the designated number of pulses. (FIG. 13, step ST
412-ST415)

(5) Main switch OFF When the main switch 64 is turned off, the flow shown in FIG.
The lens barrel is stored in the camera body according to the chart. In this storing operation, the code of the second code board 62 is
If the rear group lens 56 is at a position corresponding to any of the codes B, C, and D, DC1 is set to WIDE.
Drive control to the side. (FIG. 15, step ST500, S
T506)

The encoder pulse is counted from the time when the first code brush 60 comes into contact with the OFF code, that is, the code ZC0 of the first code board 59, and the pulse count indicates the number of stored set pulses. DC1
To stop. In this case, the first code brush 60 is
The lens barrel contacts the position of the position HP0 of the code board 59 and moves to the storage position.

When the rear switch lens 56 is at a position corresponding to the code A on the second code board 62 when the main switch 64 is turned off, the DC2 is driven and controlled to the TELE side, and The encoder pulse is counted from the time point when the code B is recognized. (FIG. 15, steps ST500 to ST
503)

When the pulse count exceeds the designated number of pulses, DC2 is stopped. (FIG. 15, steps ST504, ST505) By this operation, the rear group lens 56 approaches the front group lens 45, and thereafter, the DC1 is drive-controlled, and the process proceeds to steps ST506 to ST510 described above, where the lens barrel moves to the storage position. .

As described above, at the WIDE end (ZP1), the zoom extension amount (all the lens units) by DC1 is shift-corrected, and the focus extension amount (all the lens units) by DC1 is flange-back corrected. Then, adjust the shift between the flange back and the shift.

Other zoom positions (ZP2 to ZP)
In step 6), the zoom-out extension amount by DC1 (all lens groups) is corrected by flange back, and the extension amount by DC2 (rear group lens) is shift-corrected to adjust the shift between flange back and shift.

The correction values for flange back and shift to be written in the EEPROM 70 are determined as follows. Note that M
₁ ~M ₇ is correction de - is another. M ₁ DC1 flange back correction value M ₂ DC2 ZP1 (WIDE end) shift correction value M ₃ DC2 ZP2 shift correction value M ₄ DC2 ZP3 shift correction value M ₅ DC2 ZP4 shift correction value M ₆ DC2 ZP5 shift correction value M ₇ DC2 ZP6 (TELE end) shift correction value Of M _{1 to} M ₇ , the shift correction value of ZP1 (WIDE end) and the shift correction value of ZP6 (TELE end) are the same.

The above-mentioned correction values are set as follows. The unadjusted camera is set on the adjuster, and the flange back at the WIDE end (ZP1) and the TELE end (ZP6) is measured. Then, the measured values at the WIDE end and the TELE end are compared, and the shift correction values of the correction data M ₂ and M ₇ are obtained from the difference and written into the EEPROM 70.

The flange back at the WIDE end and the TELE end is measured again to confirm whether the values are the same.
Incidentally, the driving of DC1, DC2 is measured correction de - is corrected by motor M _2, M _7. At this time, if there is a difference in the flange back between the WIDE end and the TELE end, the correction data
Data M ₂ and M ₇ are rewritten with new shift correction values.

When there is no difference in the flange back between the WIDE end and the TELE end, and when the difference disappears, the difference between the measured value of the flange back at that time and the reference flange back value is obtained, and this difference is calculated as DC1 flange back correction as the correction value data of - writing the data M ₁ to the EEPROM 70.
As described above, the flange back and shift correction data at the WIDE end and the TELE end are written in the EEPROM 70.

The setting of the above correction values (flange back and shift) will be specifically described with reference to a focus curve 17A of an unadjusted camera as shown in FIG. WID
E end (ZP1) and TELE end flange back 17F ₁ and 17F ₂ of (ZP6) was measured, W from their difference 17S
The results shift correction de calculates the shift correction value of the IDE end - written as data M ₂ to EEPROM 70. At this time, the shift correction value is calculated such that the WIDE end shift correction value and the TELE end shift correction value are the same.

Then, the flange back at the WIDE end and the TELE end is measured again. If 17F ₁ = 17F ₂ , the measured value is compared with the reference flange back 17C, and the difference 17F ₀ is compared with the DC1. The data is written in the EEPROM 70 as a flange back correction value (correction data M ₁ ). In addition, 17D of FIG. 17 has shown the permissible range.

Next, the lens is set at the zoom position ZP2, the flange back is measured, the measured value is compared with a reference flange back, and a shift correction value of ZP2 is obtained from the difference to obtain correction data M. ₃ is written to the EEPROM 70. The same applies to the zoom positions ZP3 to ZP5. The lenses are sequentially set to ZP3 to ZP5,
Each of the flange back is measured, comparing the measured value with the flange back reference, determine the shift correction value ZP3~ZP5 from the difference, the correction de - EEPR as motor M ₄ ~M ₆
Write to OM70.

FIG. 18 shows the shift correction amounts 18S _{2 to} 18S ₅ obtained from the difference between the measured value and the reference flange back 18C as described above. These shift correction amounts are the correction data M as ₃ ~M ₆ will be written to the EEPROM 70. 18A shows a focus curve adjusted by flange back, and 18B shows an adjusted focus curve.

As can be seen from the above description, DC
1. The lens drive of DC2 is performed by the correction data of the EEPROM 70.
As a result, the adjusted focus curve 18B coincides with the reference flange back 18C as shown in an example in FIG. 18, so that a zoom lens free of a focus error due to the flange back and shift deviation is obtained.

FIG. 19 is a flowchart showing the correction value setting operation of the camera and the adjuster. As already mentioned, W
A flange back (f · b) between the IDE end and the TELE end is measured, and a shift correction value between the WIDE end and the TELE end is obtained from the difference, and written to the EEPROM 70. (Figure 1
9, Steps ST600, ST605, ST606)

When the difference between the flange back at the WIDE end and the flange back at the TELE end disappears, the correction value of the flange back is obtained from the difference between the measured value and the reference flange back.
It is written to the PROM 70. (FIG. 19, step ST
600 to ST602, ST606 ', ST607)

When the correction values for the WIDE end and the TELE end are set as described above, the zoom positions ZP2 to ZP are set.
Move on to P5 shift correction setting. In this case, shift measurement is performed for each of the zoom positions ZP2 to ZP5 to calculate a shift correction value, and the correction value is written to the EEPROM 70 as correction data. (FIG. 19, steps ST603, ST604, ST608, ST609)

[0112]

As described above, in the zoom lens focus adjusting apparatus according to the present invention, the correction values of the flange back and the shift are stored in advance in the memory means as correction data, and the correction data of the memory means are stored. Since the focus adjustment is performed by correcting the motor drive amount of the motor, the adjustment of the flange back and the shift can be easily and automatically performed by the adjuster without requiring any special parts or configuration.

In addition, the flange back and shift can be adjusted in the middle of zooming, the adjustment accuracy can be increased at each zooming position, and furthermore, the variation of assembly accuracy and the assembling time can be improved. Since the shift can be corrected even if the shift is increased due to the variation, a high-performance zoom lens can be provided.

[Brief description of the drawings]

FIG. 1 is a front view showing a lens barrel of a zoom lens embodying the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view taken along line BB in FIG. 1;

FIG. 4 is a sectional view taken along line CC in FIG.

FIG. 5 is an end view cut along the line DD in FIG. 1;

FIG. 6 is a first view illustrating a zooming operation of the front group lens.
FIG.

FIG. 7 is a second column showing the zooming operation of the rear group lens.
FIG.

FIG. 8 is a simplified view of a second code board showing a focusing operation.

FIG. 9 is an electrical block diagram showing the drive control device for the lens barrel described above.

FIG. 10 is a flowchart showing an operation of turning on a main switch.

FIG. 11 is a flowchart showing a zooming operation by DC1.

FIG. 12 is a flowchart showing a zooming operation by DC2.

FIG. 13 is a flowchart showing a focusing operation.

FIG. 14 is a flowchart showing a focusing operation.

FIG. 15 is a flowchart showing the operation of turning off the main switch.

FIG. 16 is a partial simplified view of a first code board for explaining a zooming operation.

FIG. 17 is a focus curve for explaining setting of a correction value of flange back.

FIG. 18 is a focus curve for explaining setting of a shift correction value.

FIG. 19 is a flowchart showing an operation for setting a correction value for flange back and shift.

FIG. 20 shows a conventional zoom lens, and FIG.
(B), (C) is a simplified diagram showing the operation process of extending the zoom lens to the shooting position.

21A and 21B show a zooming operation process of the conventional zoom lens. FIG. 21A shows a state in which a front group lens and a rear group lens are integrally advanced, and FIG. 21B shows a rear group. It is a simplified diagram showing each state where the lens was advanced.

FIG. 22 is a focus curve for explaining adjustment of flange back and shift in a conventional zoom lens.

FIG. 23 is a focus curve for explaining adjustment of flange back and shift in another conventional zoom lens.

[Explanation of symbols]

 Reference Signs List 31 fixed frame 32 first moving frame 33 second moving frame 34 first motor (DC1) 35 second motor (DC2) 36 drive ring 37 friction spring 43 photo interrupter 44 shutter frame 45 front group lens 54 reel Screw 56 Rear lens 59 First cord board 60 First cord brush 61 Second cord brush 62 Second cord board 63 Controller 64 Main switch 65 WIDE switch 66 TELE switch 67 Shutter switch 70 EEPROM

Continuation of the front page (56) References JP-A-4-367809 (JP, A) JP-A-5-119247 (JP, A) JP-A-5-19362 (JP, A) JP-A-3-5111 (JP) , U) (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B ⁷ /02-7/105

Claims (1)

(57) [Claims] 1. A lens system comprising at least two or more lens groups that move by zooming and the same number of motors as the number of moving lens groups, and provided for each lens group to detect the position of the lens group. And a position detecting means for detecting by counting encoder pulses, and controlling the respective motors according to the detection of the position detecting means to perform zooming and focusing. A memory means for measuring back and shift correction amounts in advance and storing the correction amounts as data, and the lens is most extended.
In the zooming position where there is little, the above-mentioned memory means is supplemented.
The lens movement amount for zooming is changed according to the positive data.
Shift correction to change the focusing lens movement amount.
At the other zooming position.
According to the correction data of the memory means described above.
-Flange back correction by changing the lens movement amount of the lens
Shift correction by changing the focusing lens movement amount
To motor - it's characterized by being more configuration and motor control means - zoom lens focus adjustment device.