JP3385478B2 - camera - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera equipped with a zoom lens barrel for switching focal lengths and focusing using motors which are the same drive source.

[0002]

2. Description of the Related Art In order to simplify the mechanism of a camera, a plurality of lens groups are moved in the optical axis direction using a motor as a drive source.
2. Description of the Related Art Conventionally, a camera has been proposed in which focusing is performed by switching a plurality of focal lengths stepwise and setting a predetermined focal length, and then using the same motor as a driving source to move a plurality of lens groups in the optical axis direction. An example using a digital pattern or a potentiometer to detect this focal length switching is known.

For example, there is a means for preparing a different pattern for each focal length using a digital pattern and detecting the focal length based on the difference in the pattern. In this case, the number of brushes in the pattern is large and the pattern is reliable. Lacks sex.

Further, there is a means for detecting the focal length by extracting each signal from the digital pattern provided for each focal length, but in this case, the number of detected bits becomes large.

When a potentiometer is used, since the output signal is an analog signal, it needs to be digitally converted for signal processing, but the conversion takes time.

[0006]

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art described above, without providing a dedicated lens group position detecting means for stopping and controlling the drive motor when switching the focal length. A camera equipped with a zoom lens that stops a drive motor based on a pulse signal and can perform focusing with high accuracy even when the lens is slightly displaced from a stop position set at the time of switching the focal length for some reason It is a thing.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there are provided a plurality of lens groups, a lens barrel for moving the plurality of lens groups in the optical axis direction for performing focal length switching and focusing, and a focal length. A single motor for driving the lens barrel at the time of switching and focusing, a first pulse generating means for generating a pulse based on the driving of the motor, and a pulse interval longer than a pulse generated by the first pulse generating means. Second pulse generating means for generating the short pulse of the motor based on the driving of the motor, and the drive control of the motor at the time of switching the focal length is performed based on the number of pulses generated by the first pulse generating means. The drive control of the motor during focusing is performed by using the pulse generated by the first pulse generating means as a trigger. It is accomplished by a camera and performing based on the number of pulses generated by the pulse generating means.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the mechanical operation of the present invention will be described in detail with reference to FIGS.

FIG. 1 is an exploded perspective view of a zoom lens barrel according to the present invention, FIG. 2 is a cross-sectional view thereof, in which the upper half of the barrel has a wide focal length, and the lower half of the barrel has a focal length. FIG. 3 is a view showing the assembling of the fixing plate, and FIG.

Reference numeral 1 denotes a fixed barrel integrally fixed to the camera body, and a female helicoid 1a is screwed on the inner periphery of the fixed barrel.
Straight guides to be described later are provided on the left and right sides of the female helicoid 1a.
A guide groove 1b for 21 is provided across the female helicoid 1a. Reference numeral 2 denotes a movable barrel, which has a male helicoid 2a and a large gear 2b screwed onto the outer periphery of the female helicoid 1a.
Are integrally formed, and a female helicoid 2c and a cam groove 2d (inner cam) are formed on the inner periphery of the flange 2 inwardly of the rear end portion.
e is provided. The tooth circle of the large gear 2b is formed smaller than the root diameter of the male helicoid 2a. When the movable body 2 and the large gear 2b are integrally molded with resin, the large gear 2b is arranged on the rear end surface of the movable body 2. By doing so, the molding die can be molded in one piece in the die cutting direction instead of dividing the molding die, so that highly accurate parts can be manufactured with a simple die structure. 3 is an FC sliding frame, F with a combined focal length of (+)
The FC lens frame 4 holding the C lens group 5 is attached from the front by screws. On the outer circumference of the FC sliding frame 3, a male helicoid 3a screwed with a female helicoid 2c and a guide groove 3b for a straight guide 21 described later are provided, and a hole 3c for a guide shaft 11 described later is formed. There is. 6
Is an RC sliding frame, and R with a combined focal length of (-) on the inner circumference
A C-lens group 7 is held, a guide groove 6a for a straight guide 21 to be described later is provided on the outer periphery, an RC cam pin 8 that engages with the cam groove 2d is embedded, and a guide shaft 11 is projected in the front. Reference numeral 13 is a shaft spring inserted into the guide shaft 11, and 12 is an E-shaped retaining ring for preventing the shaft spring 13 from coming off. Reference numeral 21 denotes a straight-moving guide, which is slidably engaged with the guide groove 1b of the fixed body 1 at the left and right protruding portions 21a, and the other protruding portion.
A drive gear 44, which will be described later, is rotatably supported by 21b, and is slidably engaged with the guide groove 3b and the guide groove 6a by the arm portion 21c bent forward. Reference numeral 22 is a guide fixing plate that connects the movable body 2 and the straight guide 21 and 23 is a straight guide 21 and the guide fixing plate 22.
Is a guide fixed shaft for connecting the movable barrel 2 with the flange 2e, and 24 is a set screw for holding the straight guide 21 on the guide fixed shaft 23. 31 is a lens barrel drive motor, the propeller 33 for LDP1 is attached to the shaft 32,
The signal LDP1 is generated by the photo interrupter 34 for DP1. 35 is a pinion directly connected to the motor,
The rotation of 31 is the first gear 36, the second gear 37, the third gear 38, the fourth gear.
A fifth gear 43 having a long gear in the optical axis direction by the gear 42
To the drive gear 44. Drive gear 44
Meshes with the large gear 2b of the movable barrel 2. A propeller 40 for LDP2 is attached to the shaft 39 of the third gear 38,
A signal LDP2 is generated by the photo interrupter 41 for LDP2. The signals LDP1 and LDP2 are signals for controlling the lens barrel drive motor, and will be described in detail later.

Reference numeral 52 is a shutter, and 53 is a shutter driving motor, which is mounted on the FC sliding frame 3. 51 is FP
It is a C board, and connects the shutter driving motor 53 and the printed board 54 on which the electrical components of the main body are mounted. F
After connecting to the shutter driving motor 53, the PC board 51 passes through a gap between the arm portion 21c of the straight guide 21 and the inner circumference of the movable barrel 2 toward the rear of the camera, and is folded back at the rear end 2f of the movable barrel 2 It passes through the gap between the outer periphery of the movable barrel 2 and the fixed barrel 1 in the forward direction. A hole 1c is provided in front of the camera from the rear end 2f of the movable body 2 when the movable body 2 is most extended to the fixed body 1. The FPC board 51 passes through the hole 1c and the fixed body 1
And is connected to the main body side printed circuit board 54. Reference numeral 51a indicates the FPC board 51 at the position where the lens barrel is most retracted. Reference numeral 61 is the external appearance of the camera, the decorative ring 62 is attached to the movable barrel 2, and the front cylinder 63 is attached to the FC sliding frame 3.

Next, the basic operation of the zoom lens barrel will be described.

First, when the drive motor 31 rotates, its driving force is transmitted to the fifth gear 43 through the gear trains 36, 37, 38, 42, and the fifth gear 43 is attached to the drive gear 44 attached to the linear guide 21. , Transmit the driving force. Drive gear 44 is large gear 2b
And the movable barrel 2 is rotated to move the fixed barrel 1 and the movable barrel 2 screwed with the helicoid in the optical axis direction. At this time, the movable barrel 2 moves forward or backward in the optical axis direction according to the rotation direction of the drive motor 31, and the drive gear 44 also moves forward or backward, so that the teeth in the optical axis direction with the fifth gear 43 meshed with each other. Although the engagement position changes, the fifth gear 43 has a long tooth width in the optical axis direction, so that the engagement does not deviate. Movable torso 2
The guide fixing plate 22, the guide fixing shaft 23,
The straight guide 21 is integrally attached by the set screw 24, but the straight guide 21 is prevented from rotating by the left and right protruding portions 21a and the guide groove 1b of the fixed barrel 1, and only moves in the optical axis direction. Similarly, the FC slide frame 3 is prevented from rotating in the guide groove 3b by the straight guide 21. Further, since the guide shaft 11 protruding from the RC sliding frame 6 penetrates the FC sliding frame 3, the RC sliding frame 6 is also prevented from rotating together with the FC sliding frame 3. Therefore, when the movable body 2 is rotationally moved, the F that is in a helicoidal connection with the movable body 2
The RC sliding frame 6 cam-connected to the C sliding frame 3 and the movable barrel 2 only moves forward or backward in the optical axis direction. The FC sliding frame 3 moves at a rate about twice that of the movable barrel 2. This ratio is determined by the leads of the inner helicoid and the outer helicoid of the movable barrel. Since the leads are set to be almost the same in the embodiment, the ratio is as described above. Although the meshing position of the fifth gear 43 and the drive gear 44 changes in the optical axis direction as the movable barrel 2 moves, the fifth gear 43 is a gear having long teeth in the optical axis direction. The meshing is always maintained regardless of the movement of the movable barrel 2. Further, the flange 2e of the movable barrel 2 has a bearing surface for receiving the rotation of the movable barrel 2 in addition to the thrust slip-out prevention of the straight guide 21, so that the movable barrel 2 is prevented from being deformed when the driving force is transmitted. There is.

The RC sliding frame 6 for holding the RC lens is driven by the cam groove 2d as described above, and its cam shape is made to be a focusing area so that focusing and focal length switching can be driven by the same driving source. , Focal length switching area.

Guide shaft 11 projecting from RC sliding frame 6
Penetrates the FC sliding frame 3 and holds the shaft spring 13 in a compressed state by the E-shaped retaining ring 12 at the tip thereof, so that the RC sliding frame 6 constantly keeps the spring force of the FC sliding frame 3. Attracted in the direction. Therefore, the cam groove 2d of the movable barrel 2
Is using only one side of the cam. Therefore, the cam groove width is larger than the cam pin width, and the groove width has a margin. In order to increase the cam operating efficiency, the standing angle of the cam groove 2d is set as close as possible to the side of the shaft spring 13 to which force is applied, and the standing angle of the cam groove is asymmetrical in the front and rear so that plastic molding can be performed. Further, during focusing, the spring force moves in the direction of increasing spring force, and during zooming up, the spring force moves in the direction of decreasing spring force. Since the cam groove 2d is open in the front direction of the optical axis, R
When the C sliding frame 6 is incorporated into the movable barrel 2, it is incorporated from the front of the movable barrel 2. This RC sliding frame 6 is an FC sliding frame 3
Since it is connected to the guide shaft 11 (including the shutter 52, etc.), it is incorporated into the movable barrel 2 as an FC / RC sliding frame unit. At that time, the RC sliding frame 6 is FC
If it is pulled toward the sliding frame 3, the workability of assembly is good. Moreover, by making the RC sliding frame 6 cover the RC sliding frame 6, it is possible to prevent the RC lens group 7 of the RC sliding frame 6 from being damaged.

Normally, lens performance such as projection resolving power is inspected at the stage of the movable barrel unit including the FC / RC sliding frame unit. However, if the movable barrel on the outer surface of the current unit is rotated, the focal length is increased. Since you can select and adjust the focus,
The inspection efficiency is very high and does not require extensive electrical jigs. If the lens performance such as the projection resolution can be inspected in this state, defects and the like can be detected quickly, and the time and cost for disassembly repair can be saved. This unit has a shutter drive, F
It is easy to replace the FC lens due to a defect caused by the FC lens because the PC, the lens cover, etc. do not need to be incorporated, and the focusing mechanism is not included. The straight guide 21 is incorporated, and two guide fixing plates 22 for retaining rotation receivers of the straight guide 21 are incorporated. This is shown in FIG.
And FIG. 3B. In FIG. 3 (A),
In order to improve the assembling workability, the two fixing plates 22 are temporarily fixed to the rectilinear guide 21 one by one with the setscrews 24, and after the rectilinear guide 21 is incorporated into the movable barrel 2 from the rear of the camera,
By rotating the set screw 24 in the clockwise direction, as shown in FIG. 3B, the set screw 24 and the set screw 25 are screwed and connected to the straight guide 21 at a total of 6 positions. In this way the straight guide 21
Since it is possible to guide the fixed barrel 1 and the FC sliding frame 3 in a straight line with a single component, the FC sliding frame 3 has a high precision of straight line movement, and the efficiency of the driving force for performing the straight line movement is high.

The movable barrel 2 moves in synchronization with the linear guide 21 in the optical axis direction. A drive gear 44 is attached to the linear guide 21. Therefore, even if the movable barrel 2 moves in the optical axis direction, the position of the drive gear in the optical axis direction does not change.
The large gear 2b shown in 1 has a simple shape having a tooth width only a predetermined length from the rear end surface. This is to reduce the size of the large gear 2b in the optical axis direction as much as possible.

Next, drive control of the zoom lens barrel will be described in detail.

FIG. 4 is a timing chart of control signals, showing changes in each signal when the lens barrel drive motor is normally rotated and the lens barrel moves from the retracted end to the telephoto end.

The signal used for the drive control is L for detecting the rotation of the lens barrel drive motor 31 by the photo interrupter 34.
It is controlled by three components: DP1, LDP2 for detecting the rotation of the third gear 38 in the gear train by the photo interrupter 41, and SPOS for detecting the retracted end position of the lens barrel by a unit Sw (not shown). Every time the lens barrel drive motor makes one rotation, L
DP1 changes by 6 pulses. During one cycle of LDP2 (from the rising edge of the signal to the next rising edge), LDP1 changes about 214 pulses. LDP1 is about 24 while LDP2 is logical value "1".
The pulse changes. The position where the first SPOS is "1" is the collapse end. The wide end position is the state position where LDP2 is "1" after SDP changes to the logical value "0" and LDP2 changes by 5 pulses. Later LDP2
The lens barrel standby position is set for each state of “1” that is changed by 2 pulses, and a total of five lens barrel standby positions including the wide end position and the tele end position are set.

The focal length is divided into F at the wide (W) ∞ focus image forming position and at the tele (T) ∞ focus image forming position.
The distance difference from the focus surface of the C lens is divided into integers.
This is because the focal length is controlled by the LDP2 that periodically generates a signal. As a method of selecting the focal length for each fixed amount of motor rotation, L
This is because the generation of DP2 is cheaper, smaller, and can be performed without contact. In other words, wide (W) ∞, middle 1 (M1) ∞, middle 2 (M2) ∞, middle 3 (M3)
The positions of the FC lens group 5 at the image forming positions at ∞ and tele (T) ∞ are at equal intervals, and the amount of rotation of the motor is also the same amount. Although it is not always necessary to equidistantly set, the lens driving at the time of focusing becomes the same for each focal length if set to equal intervals, so that no unnecessary focusing time is generated for each focal length. In addition, there is no loss for each focal length in setting the allowable focus adjustment amount.

The LDP2 used for this focal length control is used as a trigger for starting the count of the feed pulse during focusing, and the focus can be adjusted by mechanically changing the generation timing of this LDP2. . Specifically, the LDP is lightly press-fitted into the third gear 38.
The generation position of LDP2 is changed by slipping the 2nd propeller 40 in the rotation direction. The adjustment space for changing the position of the propeller that periodically occurs can be minimized, and focus adjustment can be performed in a small space. This adjustment is performed as a general focus adjustment action of the lens barrel unit before it is attached to the main body, and ∞ adjustment is performed at the wide end where the error sensitivity is low. After that, in the finished camera product, focus adjustment is performed for each focal length, and the deviation from the rough adjustment and the deviation for each focal length are stored in the EEPROM as pulse numerical data.

Focus adjustment is performed by changing the timing of LDP2 generation or by correcting the pulse counted from the trigger, and in either case, it is performed only by adjusting the rotation angle of the cam barrel.

The LDP 2 is also used as a trigger signal for starting the stop control of the stop control when the focal length is selected.
The width of the Hi level of LDP2 is about 23 pulses. This is when the motor is controlled by the feeding side (ZOOM-UP) and stopped, and when the motor is controlled by the feeding side (ZOOM-DOWN) and stopped. It is set to generate almost the same pulses as the required number of pulses added.

LDP2 pulse width = ZOOM-UP stop pulse + ZOOM-DOWN stop pulse With this setting, no matter which direction the lens barrel is stopped,
DP2 is stopped at Hi. Furthermore, even if it stops from any direction, it stops at almost the same position.

Even when the zoom operation is performed with a button or the like outside the camera, whether or not to shift to the zoom stop control is evaluated when the LDP 2 rises. Therefore, since the focal length changeover switch is evaluated only when the rise of the LDP 2 changes, the focal length changeover switch does not cause a problem even if Sw has a lot of chattering, and the lens barrel does not malfunction even if the switch is operated intermittently. .

Since it is premised that the LDP 2 of the lens barrel is stopped at the Hi position at any focal length at the time of photographing, when the LDP 2 at the start of focusing is not Hi,
The lens barrel is initialized because it is judged as an external operation error (manually rotating the cam barrel).

The LDP2 has the following functions.

1. Position management when selecting the focal length (number of pulses from the initial position) 2. 2. Stop control trigger signal when selecting the focal length for external operation 3. Outgoing count trigger signal during focus control 4. 4. Stop control trigger signal for position return control after focus control External erroneous operation detection function 6. Focus adjustment function In conventional zoom cameras, in the case of a lens barrel that has a backlash during zoom control, in order to improve focus performance, for example, during reverse rotation control, the lens is stopped last in the normal rotation drive state, and the backlash of the mechanism is reduced to the normal rotation side. It was absorbed in the driving state. However, after zooming, if you touch the lens barrel with your hand, the backlash that was absorbed will be released, and if you release your hand afterwards, the focus will change significantly.

In the case of the present invention, the drive unit for switching the focal length and the drive unit for performing the focus have the same mechanism. Therefore, by controlling on the forward rotation side at the time of focusing, backlash in the focal length switching operation can be controlled by an external device. Even if the backlash is released by the operation, or if the lens barrel is intentionally moved back and forth, the backlash will be removed at the time of focusing, so the backlash absorption control of the lens barrel is unnecessary and stable focusing performance is obtained. be able to.

Next, the lens barrel drive motor control will be described in detail with reference to FIGS.

FIG. 5 is a block diagram of the control circuit of the camera.

The CPU 71 controls all the cameras including SW input, information processing, motor drive control, and liquid crystal display drive. Connected to the CPU 71 are a power supply circuit 72 that supplies a constant voltage to the battery power and supplies it to the CPU 71, an EEPROM 73 that stores various information processing data for shooting, a main body of release, main, zoom up, and zoom down. SW group 74, DX input circuit 75 for inputting ISO sensitivity of DX film, collapsing SW76 for outputting signal SPOS for detecting the collapsing end of the lens barrel, strobe circuit 77 for auxiliary lighting, photometric circuit 78 for measuring subject brightness, Distance measuring circuit 79 for measuring subject distance, motor driving circuit for driving lens barrel driving motor, shutter motor, film feeding motor
80, signal LDP1 for detecting the amount of rotation of the lens barrel drive motor,
A lens barrel drive detection circuit 81 for outputting LDP2, a film feed detection circuit 82 for detecting the film feed amount, a shutter drive detection circuit 83 for detecting the movement of the shutter, a liquid crystal display section 84 for displaying photographing information, a mode, Rewind back cover SW
There is a group 85.

The lens barrel drive motor control has the following items.

Collapse: Initial setting of the lens barrel that stores the entire lens barrel in the camera body: Zooming to set the lens barrel to an initial position where shooting is possible Zooming: Changing the focal length Focusing: Adjusting the focus position Stop position check: Check that the lens barrel is stopped in the normal position.

FIG. 6 shows a flow chart of the collapsing control. Position where SPOS becomes 1 (Collapse end position)
The purpose is to move the lens barrel. When the camera is not used, it can be compact and portable if it is stored in the body of the camera with the shortest lens length.

At step 100, the CPU 71 causes the SPOS
Is detected to determine whether the current lens barrel position is at the retracted end (state 1) or at the image-capturing position (state 0). If SPOS is 0, the process proceeds to step 104. SP
If the OS is 1, the CPU rotates the lens barrel drive motor 31 forward in step 101 and waits until SPOS becomes 0 in step 102. When SPOS becomes 0, the lens barrel drive motor 31 is stopped in step 103. In step 104, the lens barrel is at a position other than the retracted end. The CPU 71 reverses the lens barrel drive motor 31 to move it to the retracted end position. After waiting until SPOS becomes 1 in step 105, the lens barrel drive motor 31 is stopped in step 106.

By the above-mentioned collapsing control, it is possible to move the lens barrel to the collapsing end position regardless of the position.

FIG. 7 shows a flowchart of the lens barrel initial setting control. The objective is to move the lens barrel at the retracted end position to the wide end position and wait so that shooting is possible.

In step 200, the CPU 71 rotates the lens barrel drive motor 31 forward, and in step 201, waits until SPOS becomes zero. When SPOS becomes 0, step 20
In 2 to 206, 5 pulses of 2 LDP pulses are counted. The count ends when the state of LDP2 is 1. In step 207, the CPU 71 stops the lens barrel drive motor 31, and in step 208 sets a plurality of divided focal length position information (hereinafter referred to as zoom zone) at the wide end and stores it. In the photographable area, the LDP 2 is controlled to stand by in the state of 1 regardless of the focal length of the lens barrel.

FIG. 8 shows a flowchart of zooming control. The purpose is to change the focal length according to the operation of the zoom switch.

In step 300, the CPU 71 detects the state of the zoom-up switch, and if it is on, proceeds to step 313. If it is off, the state of the zoom down switch is detected in step 301, and if it is off, the flow ends.
If it is on, it is determined in step 302 whether the zoom zone is at the wide end, and if it is the wide end, the flow ends. If it is not the wide end, the lens barrel drive motor is reversed in step 303. In steps 304 to 308, two LDP pulses are counted. The count is 1 for LDP2
Ends with. The focal length is moved by counting two pulses, and in step 309, one zone down of the zoom zone is stored. It is set so that one zoom zone changes when the LDP2 pulse changes by two pulses, and the standby position is not set in the meantime. LDP2
When the number of pulses is counted by 2 and the LDP2 pulse is 1, the zoom down SW state is detected in step 310, and if it is off, the lens barrel drive motor 31 is stopped in step 312. If it is on, it is judged at step 311 whether the zoom zone is at the wide end. If it is at the wide end, the lens barrel drive motor 31 is stopped at step 311. If it is not at the wide end, the process returns to step 304 to continue counting LDP2 pulses. Zoom down while driving the lens barrel drive motor
Instead of constantly monitoring the SW status, step 304
By detecting the state of the zoom down SW only when the count of ~ 308 is completed and the LDP2 pulse is in the state of 1,
It is possible to simplify the control. Step 31
In 3 to 322, basically the control is the same as the control in steps 302 to 311 except that the rotation direction of the lens barrel drive motor is different and that the zoom zone is limited at the tele end, so description thereof will be omitted. .

FIG. 9 is a flow chart of focusing control, and FIG. 10 is a timing chart of focusing control, showing the voltage between terminals of the lens barrel drive motor and changes in each signal.

The CPU 71 calculates the defocus amount to the in-focus position in each zoom zone from the distance measurement result,
It is converted into the count number of LDP1 pulses based on the falling edge of LDP2. The purpose of this conversion is to move the lens barrel to the in-focus position.

In step 400, the CPU causes the lens barrel drive motor 31 to rotate normally. Regardless of the zoom zone where the lens barrel is located at this point, the state of LDP2 must be 1, and in step 401 LDP2 changes from 1 to 0.
Wait until the status changes to. When the trailing edge of LDP2 is detected in this manner, counting of the leading edge of the LDP1 pulse is started in step 402 with this position as the base point. In step 403, it waits until the rising edge count value of the LDP1 pulse reaches the defocus amount conversion value, and in step 404, the lens barrel drive motor 31 is braked and stopped. The lens routine drive motor braking routine is not mentioned in the flowchart, but
As shown in the timing chart of 10, the reverse and forward voltages are applied to the motor terminals alternately to brake.
Further, the LDP 2 is used not only for detecting the zoom zone in the lens barrel initial setting control and zooming control but also for detecting the base point position of the focus position adjustment in the focusing control.

FIG. 11 shows a flowchart of the stop position confirmation control. In the imageable area, the lens barrel controls the LDP 2 to stop at the position of 1 as described above. However, when the lens barrel is erroneously operated from the outside, the LD
In some cases, P2 may move to the state of 0. Before and after the lens barrel initial setting control, zooming control, and focusing control, whether or not the state of LDP2 is 1 is checked, and if the state is not 1, the objective is to move the lens barrel to a normal position. In step 500, the CPU 71 sets LDP2
The state is detected, and if the state is 1, the flow ends. If the state is 0, the aforementioned collapse control is performed in step 501,
Move the lens barrel to the retracted end position. In step 502, the above-described lens barrel initial setting control is performed to move the lens barrel at the retracted end position to the wide end position and wait. In this embodiment,
Although it is moved to the wide end position, it may be stopped at the retracted end position. As described above, according to the present embodiment, the pulse signal LDP2 is used as a stop control trigger signal when switching and selecting the focal length from wide to tele or from tele to wide, and when the lens barrel is erroneously operated from the outside. Since it is used as the erroneous operation detection signal, the remarkable effect that a camera with a zoom lens having a simplified signal generation circuit can be realized.

[0047]

As described above, according to the present invention, focal length switching and focusing are performed by driving a common motor, and drive control of the motor at the time of focal length switching is based on the number of pulses generated by the first pulse generating means. In addition, the drive control of the motor during focusing is performed based on the number of pulses generated by the second pulse generating means by using the pulse generated by the first pulse generating means as a trigger. It is not necessary to provide a separate lens group position detection means exclusively for motor drive control at the time of focal length switching, and the motor drive control at the time of focusing can obtain a highly accurate and stable focusing performance. Play.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a zoom lens barrel according to the present invention.

FIG. 2 is a cross-sectional view of a zoom lens barrel.

FIG. 3 is a view showing an assembling of a fixing plate.

FIG. 4 is a timing chart of control signals.

FIG. 5 is a block diagram of a control circuit of the camera.

FIG. 6 is a flowchart of retractable control.

FIG. 7 is a flowchart of a lens barrel initial setting control.

FIG. 8 is a flowchart of zooming control.

FIG. 9 is a flowchart of focusing control.

FIG. 10 is a timing chart of focusing control.

FIG. 11 is a flowchart of stop position confirmation control.

[Explanation of symbols]

1 fixed body 2 movable torso 21 Straight ahead guide 31 Lens barrel drive motor 33 Propeller for LDP1 34 Photointerrupter for LDP1 40 Propeller for LDP2 41 Photointerrupter for LDP2 43 5th gear 44 Drive gear 71 CPU 76 Crash SW 79 Distance measuring circuit 80 motor drive circuit 81 Lens barrel drive circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02B ⁷ /02-7/16

Claims (2)

(57) [Claims] 1. A plurality of lens groups, a lens barrel for moving the plurality of lens groups in an optical axis direction for switching focal lengths and focusing, and driving the lens barrel during focal length switching and focusing. A single motor, first pulse generating means for generating a pulse based on the driving of the motor, and a pulse having a pulse interval shorter than the pulse generated by the first pulse generating means based on the driving of the motor. A second pulse generating means for generating the second pulse, and for controlling the drive of the motor at the time of switching the focal length,
While performing based on the number of pulses generated by the pulse generating means, the drive control of the motor during focusing,
A camera characterized in that the pulse generated by the first pulse generating means is used as a trigger, and the trigger is performed based on the number of pulses generated by the second pulse generating means. 2. The first pulse generating means and the second pulse generating means each include a rotating member that is rotated in association with driving of the motor, and each pulse is generated by rotation of each rotating member. Claim 1 characterized by the above.
The camera described in.