JPH0318297A - Mechanism driver in lens - Google Patents

Abstract

PURPOSE:To always effectively and rapidly perform an initial reset confirming operation by storing and holding a phase exciting state in a memory irrespective of ON/OFF of a main power source. CONSTITUTION:An initial position exciting phase is written in an E<2>PROM at the times of assembling and regulating. The initial position exciting phase is first read from the E<2>PROM at the time of operation. A motor is turned ON in the exciting phase, and held at the initial position. Then, if an initial position sensor is not turned ON, the motor is driven by -1 step toward the initial position. This operation is repeated until the sensor is turned ON. If it is turned ON, the motor is stopped to be turned OFF. If the sensor is already turned ON, the motor is once driven toward +1 step. This is repeated until the sensor is turned OFF, and it is then stepped to the sensor side. When the sensor is turned ON, the motor is turned OFF. Thus, an initial reset confirming operation can be always effectively and rapidly performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field in Icheon] This invention relates to an internal lens mechanism drive device, specifically, an aperture mechanism and a focusing lens moving mechanism disposed within a lens mirror of a camera, etc. This invention relates to an in-lens internal drawing drive device that uses a stepping motor to drive the side of the driving device inside the lens, such as the AF device side.

[Prior Art] A stepping motor is used as an actuator for driving the aperture drawing and AF mechanism built into the lens mirror of a camera to control the open loop 1.
Traditionally, it has been commonly carried out, and
It is well known from the publication No. 9.

For example, in the aperture control method of a camera, this open-loop control always starts the aperture from the initial open aperture position and performs the aperture. This is to control so as to return it to the initial position. In other words, it is always held at a constant position (initial position) so that the opening position is set to 1. It is preferred because it can be used.

Further, the initial position is the aperture open position when it is next to the diaphragm, and the infinity position of the lens when it is an AF mechanism.

However, with this open-loop control, it is necessary to check whether the driven mechanism has been accurately reset to the initial position after each photographing session. This reset confirmation means has conventionally provided a position detection sensor at an initial position, and uses this sensor to confirm whether or not the reset has been performed.

[Problem to be resolved whether it is an invention or not] However, in the conventional lower stage of reset confirmation described above, the initial reset is performed based only on the output f≦ of the initial position detection sensor, and the initial position of the stepping motor is not reached. This has the disadvantage that it is inefficient and takes time to return to the initial position regardless of the excitation phase of the camera.Also, this is fatal for cameras where momentary photo opportunities are particularly important. Become.

In addition, recent cameras generally have a large amount of CPU,
RAM is used as the memory means.

Therefore, by using this RAM, once the reset 1 operation is performed, the excitation phase at the initial position of the stepping motor is stored in this RAM, and this information is used thereafter to effectively perform the initial reset 1. Some have done this. However, since this means uses the RAM in the CPU when the power is turned off, this information disappears.
When performing the initial reset operation immediately after the power is turned on again, there is a drawback that it takes time and is inconvenient, similar to the above-mentioned case using the conventional initial position detection sensor.

On the other hand, check the initial reset 1 and operation.
In order to do this quickly, it is necessary to keep the excitation phase of the stepping motor constant at the initial position, such as by adjusting the f1 position of the stepping motor or adjusting the drive force transmission system when adjusting the side of the aperture drive machine or the AF drive mechanism. It is also possible to set it in four phases, but when assembling and adjusting it, the number of T's becomes large because the excitation phase is installed and adjusted so as to have only one pair.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks of the conventional technology, and to provide a camera diaphragm mechanism and an AP machine (7y) that perform open-loop control using a stepping motor, and that are reliable at 'j:'r and have an initial reset at a high speed.・Provides an internal lens drawing drive device that enables confirmation operations.

[Means and operations for solving the problem] The lens mechanism driving device according to the present invention can be used as a drive source for driving driven mechanisms in the lens, such as a lens moving mechanism for adjusting a diaphragm or a sunspot. 5 an initial position sensor that detects that the driven machine is at a predetermined initial position; and 5 an initial position sensor that detects that the driven machine is at the initial position. memory means for storing the phase excitation state of the stepping motor in relation to on/off of the main power supply when the main power supply is turned off, and immediately after the main power supply is turned on again after the main power supply is turned off. The present invention is characterized by comprising: motor drive circuit means for starting excitation drive of the stepping motor from a phase excitation state stored and held in the phase excitation state or a phase excitation state next to the phase excitation state.

[Example] The present invention will be explained below with reference to an illustrated embodiment.

In this embodiment, a case will be described in which the diaphragm mechanism is controlled in an open loop by a stepping motor employing a two-phase excitation drive method having four excitation phases.

FIG. ? 1 is a block diagram schematically showing a loop control system; FIG.

A motor drive pulse control signal is output from a control circuit 1 including a microcomputer to a motor drive circuit 2, and this control signal is sent to the motor drive circuit 2.
is adapted to drive and control the stepping motor 3.

The number of motor drive pulses mentioned above is determined by the motor drive circuit 2 (
6:+The counted counter value is 1*1, and the camera body (not shown) is configured to recognize this counter count value as the aperture value. The stepping motor 3 receives motor drive pulses from the motor drive circuit 2, and
The aperture control of the aperture mechanism 4 is performed f-i. Squeezing machine 1lI'1
4 changes the diaphragm aperture diameter in accordance with the M rotation of the stepping motor 3, so that the ``diaphragm'' always returns to the initial position of the aperture and is maintained in its normal state. The initial position detection sensor 20 detects the aperture opening of the aperture mechanism 4 and gives a predetermined control command to the control path 1.
This detection sensor 20 will be explained in detail later.

The squeeze machine +i'& 4 and the stepping motor 3 are constructed as shown in FIG. That is, the output of the stepping motor 3 is equipped with a pinion gear for driving the aperture.
3a is fixed. This pinion gear 3a meshes with a sector gear 5a formed protrudingly from a part of the arrow wheel 5 of the aperture mechanism 4. The aperture mechanism 4 includes a donut plate-shaped arrow wheel 5 that opens and closes a plurality of aperture blades 6 (only one is shown in the figure), and cam slots 5b for operating the blades, which are bored at equal intervals in the arrow wheel 5. A plurality of aperture blades are rotatably held in support holes 6b by support pins 7b installed at equal intervals on the donut-shaped bottom plate 7a of the storage case 7. 6, and a storage case 7 in which the aperture blades 6 and the arrow wheel 5 are housed, and an elastic C ring 8 for preventing them from falling out is fitted into an inner periphery 7c bored inside the peripheral wall. The pinion gear 3a of the stepping motor 3 meshes with a sector gear 5a which is provided on a part of the arrowhead 5 and projects outward from the storage case 7.

In the diaphragm {j11 which is configured with +M in this way, when the stepping motor 3 is driven by pulse control (=), the sector gear 5a is driven by the pinion gear 3a, and the arrow wheel 5 is rotated by a predetermined angle. The diaphragm blades 6 are opened and closed by the drive pin 6a fitted in the cam slot 5b, thereby changing the diaphragm opening diameter and forming a predetermined diaphragm opening.

FIGS. 3(A) to 3(C) are diagrams showing a specific structure of the detection sensor 20. FIG. The detection sensor 20 shown in FIG. 3(A) has a photointerrupter 21 consisting of a light emitting element and a light receiving element arranged opposite to a support body formed in a U-shape, and arranged so as to straddle a gear 3a. And the same gear
The rotational position range of the arrow wheel 5 is detected by detecting the presence or absence of light passing through the partially arc-shaped through hole 3b provided in the arrow 3a.

The initial position detection sensor 20 shown in FIG. 3(B) is
In addition to the pinion gear 38, a cam disk 22 made of a plate cam is attached to the output leg of the stepping motor 3, and a photointerrupter 21 similar to the one described above is arranged so as to straddle this cam solid plate 22. The detection sensor 20 detects the four-turn position of the arrow rli5 by detecting the presence or absence of light passing through the cut arrow portion 22a provided at the peripheral portion of the cam disc 22.

FIG. 3(C) is an example in which a photo reflector 23 is used as the detection sensor 20. In other words, pinion gear 3
Separately from a, a disc 24 is installed around the periphery of which a reflecting member 24a is provided over a predetermined angle range in response to the co-rotating output of the stepping motor 3, and a photo reflector 23 is provided at a position facing this disc 24. It is something that This detection sensor 20 detects the rotational position of the arrow wheel 5 based on the difference in the ratio of 1.j between the portion where the .n=t member 24a is provided and the portion where it is not provided.

The drive control method of the stepping motor that drives the aperture mechanism in this way is based on the vibration damping speed ".IJ" at the P stop position of the rotor. A well-known two-phase excitation drive system is used.

FIG. 4 shows the electrical control circuit]0 in the apparatus of the present invention, and FIG. 5 is a chart showing the relationship between the CPU output and the excitation phase of the stepping motor 3.

As shown in FIG. 4, in this bipolar excitation drive system, coils Ll and L2 are each wound with one winding on opposing poles in the stator of the stepping motor.
This is a method of excitation by changing the current direction by passing a current from the φ1 side (φ2 side) or by flowing a current from the φ3 side (φ4 side).

Therefore, the driving path is transistors Q5 to Q8.
, Q'9 to Ql2 are bridge-connected, and corresponding coils Ll and L2 are connected between the midpoints of the bridges. Then, these transistor bridges are connected to a DC power source (between Vec and ground). In addition, each transistor Q5 to Q8, Q9 to QI2 has a transistor between the emitter and collector, and a diode D1 of IJI1.
~D4, D5~D8 are connected. Of each transistor, Q5 is located on the diagonal of the bridge.
11 and Q8, Q7 and Q6, Q9 and Q12, QIO and Qll
By turning on and off as a pair according to the excitation sequence, excitation control of the coils Ll and L2 and control of the excitation direction are performed.

The CPU is composed of a microprocessor that performs camera sequences and overall control, and plays the central role of control. PO to P3 are the output ports 1 and 1.
・P4 is a human-powered boat.

Output port 1-PO-P3 is port 1 for controlling the excitation and current direction of the coils Ll and L2, and output port 1-PO is connected to the base of transistor Q1 through resistor R2. There is. The transistor Q1 is for driving the transistor Q5 constituting the bridge, and its collector is connected to the base side of Q5 via a resistor Rll, and its emitter is grounded. Further, the output port PO is connected to the base of the transistor Q8 via a resistor R4.

In addition, the output port P1 is connected to the base of the transistor Q6 via the resistor R3, and is connected to the base of the transistor Q2 via R5. This is for driving the horizontal transistor Q7, and its collector is connected to the bottom side of Q7 via a resistor RI2, and its emitter is grounded.

Output port}P2 is connected to 1 transistor Q3 via resistor R6
The transistor Ql2 is connected to the base of the transistor Ql2 via a resistor R7.

The 1 transistor Q3 is for driving the 1 transistor Q9 forming the +M bridge, and its collector is connected to the base side of the transistor Q9 via a resistor Rl3, and its emitter is grounded.

Further, the output port P3 is connected to the base of the transistor QIO via a resistor R8, and is also connected to the base of the transistor Q4 via a resistor R9. The transistor Q4 is for driving the transistor Ql1 constituting the bridge, and its collector is connected to the base side of Q9 via a resistor RI4, and its emitter is grounded.

In the stepping motor excitation 13 magnetic drive control circuit configured in this way, when the motor is driven, the CPU sequentially sends 1 transistor drive output pulses from its output ports PO to P3 in accordance with the motor excitation sequence. is generated and excites the coils Ll and L2. That is, P.O.
When a driving pulse is generated, Q] is turned on, which turns on Q5, and Q8 is also turned on due to a driving pulse from PO, so that a current flows in the coil L1 in the direction from φ1 to φ3, and it is excited. be done (
Excitation phase A). Next, when switching from PO to P2 and generating a drive pulse, Q3 turns on, which turns on Q9, and also turns on Q12 due to the drive pulse from P2, which causes current to flow in coil L2 in the direction from φ2 to φ4. flows and is excited (excitation phase B). Next, the driving pulse is generated by switching from P2 to P1. Then, Q2 turns on, which turns on Q8, and the
Q6 is also turned on by the drive pulse from . Next, when switching from P1 to 14 P3 and generating a drive pulse, Q4 turns on, which turns on Ql+, and the drive pulse from P3 also turns on QIO, which causes coil L2 to move from φ4 to φ2 direction. A current flows and it is excited (excitation phase D).

Therefore, as shown in FIG. 5, the excitation phase is controlled to four phases by the CPU output. By repeating this sequence, when the excitation phase is excited from A to B-C to D, the motor rotates in the forward direction, and when it is excited from D-C to B-A, the motor rotates in the reverse direction. Do this.

And, for the CPU person Capo 1 and P4, Maemi Figure 3 (
The initial position detection sensor Sl (21.23) consisting of the photoinruptor etc. explained in A) to (C) is connected. That is, the light emitting element Sla of the above-mentioned Kensen sensor S1
is connected between the source and the ground via a pull-up resistor RIO, and the phototransistor, which is the light receiving element Slb, has its collector connected to the input port P4, and a pull-up resistor R1 is connected between the power source and the ground. Connected via 15.

The output of this initial position detection sensor S1 connects the optical path from the light emitting element Sla to the light receiving element S i b to the pinion gear 3a (see FIG. 3(A)) or the cam disk 22 (see FIG. 3(A)).
(see Fig. 3 (B)) or the reflective disk 24 (see Fig. 3 (C)
), etc.), the light receiving element S
1. Since b is turned off, it becomes a high level due to the power supply voltage VCC pulled up by the resistor R1, and becomes a low level when it is not shielded from light.

Therefore, the initial position is set to either high level or low level.

On the other hand, the CPU is provided with a ROM for storing the initial position excitation phase, and this ROM is composed of an E2FROM. It is glued to the data line.

Next, we will discuss the operation including the initial position TIt recognition operation in the aperture mechanism 16 that is open-loop controlled by the stepping motor configured as described above. 3, the initial position excitation phase write operation is performed. This operating procedure is shown in the flowchart of FIG. 6(A). That is, in this state, since the initial position excitation phase is not determined, one of the excitation phases ABCD is read as fixed data. and,
The motor is turned on during this excitation phase.

Next, in this state, it is checked whether the initial position detection sensor is turned on, and if NO, that is, if it is not turned on, the motor is driven 11 steps toward the initial position. After driving by -1 step, it is checked once again whether or not the initial position sensor is on. If not, repeat this. If it is, stop the motor and turn it off. In addition, if the initial position sensor is already turned on while the motor is energized, the initial position sensor will be YES.
Drive toward one step and repeat this until the initial position sensor turns OFF. After that, the initial position sensor steps all the way. Then, I entered the initial position sensor.
Turn off the motor at the 1.9 point, and write this position into the E2PROM from the CPU as the initial position excitation phase. This completes the write operation to the initial position excitation phase.

Next, the initial reset 1 operation when the power is turned on will be described. The sequence flow at this time is as shown in FIG. 6 (I3). First, the initial position excitation phase is read from E2FROM. Next, the motor is turned on in the excitation phase. Therefore, the motor is held at the initial position itself. Next, it is checked whether the initial position sensor is on. If the sensor is not inserted here, the motor is driven -1 step toward the initial position. Then, it is checked once again whether or not the initial position sensor is engaged, and if it is not engaged, this is repeated, and if it is engaged, the motor is stopped in that state and OF18 F is performed. In addition, if the initial position sensor is already inserted, in this case, in order to detect the entry point of the initial position sensor,
Repeat this until the first light position sensor turns OFF by tricking the motor toward the +1 step, and then,
Initial position sensor steps all the way. Then, the motor is turned off when the initial position sensor is detected.

To explain this using the 7th garden, the above E2PR
The initial position excitation phase written in OM is, for example, excitation phase C.
If so, the ON/OFF position of the initial position sensor is
It must match this excitation phase C. Therefore, the initial position sensor is matched with the excitation phase C by driving the motor by +1 step or -1 step.

Next, as shown in Figure 6 (13), when the initial position sensor is inserted, a check is made to see if it is the same as the excitation phase stored in the E2FROM, and if it is the same, it is assumed to be normal. End the operation with YES. Moreover, in the case of No, abnormality processing is performed by turning on a warning light or the like. The above is the initial reset operation when the power is turned on.

Next, the diaphragm driving operation of the iris and iT will be explained with reference to the flowchart of FIG. 6(C). In this aperture AK operation, first, the excitation 1 phase data written in t0 is read out from the E2PROM and the motor is turned on. Then, the exposure operation is performed by controlling the diaphragm to a certain aperture by the 10-step operation of the motor. After that, the motor moves 10 steps and the wringer HLLF turns OFF overnight.
Then, the aperture drive operation ends.

In this way, after the camera is assembled in the factory, the excitation phase that corresponds to the initial position of the step motor for driving the diaphragm mechanism or AF mechanism differs for each camera. Once, the initial position detection sensor was removed and the initial reset operation was performed, and then? The excitation phase information at the initial position is detected and stored in a special memory means, that is, E2FROM or RAM held by a backup battery, so that information will be used from now on. 20.Regardless of whether the camera is turned on or off, it will always be
In addition, the aperture or AF can be initialized quickly, and the time lag until the aperture becomes ready for photographing can be shortened.

[Effects of the Invention] As described above, according to the present invention, when the main power supply is turned off again, the lens starts up quickly, becomes ready to take pictures, and the camera , there is less chance of missing a photo opportunity.

[Brief explanation of the drawing]

FIG. 1 is a block diagram schematically showing an open loop control system for an aperture drive mechanism using a stepping motor to which the present invention is applied; FIG. 2 is an exploded perspective view showing an example of an aperture drive mechanism using a stepping motor; Figure 3 (A), (B), and (C) show the initial
4 is a perspective view showing each example of the position detection sensor, FIG. 4 is an electrical control circuit diagram of the aperture drive mechanism including the stepping motor drive circuit, and FIG. 5 is a diagram showing the relationship between the CPU output and the excitation phase of the stepping motor. Fig. 6 (A) is a flowchart showing the procedure for writing the initial position excitation phase of the stepping motor; Fig. 6 (B) shows the initial reset 1 operation when the power is turned on. Flowchart 1. FIG. 6(C) is a flowchart showing the normal aperture driving operation, and FIG. 7 is a diagram showing the relationship between the excitation phase and the initial position sensor. 2...Motor drive circuit 3...Stepping motor 4...
・・・Drawing by drawing machine

Claims (1)

[Claims] (1) A stepping motor as a drive source for driving a driven mechanism in the lens such as an aperture mechanism or a focusing lens moving mechanism, and an initial position for detecting that the driven mechanism is at a predetermined initial position. a sensor; and a memory means for storing and retaining the phase excitation state of the stepping motor, regardless of whether the main power source is on or off, when the initial position sensor detects that the driven mechanism is at the initial position. Immediately after the main power source is turned off and then turned on again, the stepping motor is excited and driven from the phase excitation state stored in the memory means or the phase excitation state next to this phase excitation state. 1. An intralens mechanism drive device comprising: motor drive circuit means for starting;