JP2892192B2 - Lens movement control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens movement control device for moving a lens position for performing zooming control, focusing control, and the like.

[0002]

2. Description of the Related Art Zooming in a camera generally includes:
Cylindrical body (zoom ring) engaged with lens barrel by cam mechanism
Is rotated, and the zoom position information is indispensable as a parameter when performing shooting control such as determination of a focal length and aperture control. Therefore, when zooming is performed, the zoom position is detected. Like that.
Conventionally, as a device for detecting a zoom position, a bit-compatible switch contact is attached to a peripheral surface of a zoom ring to indicate zoom position information by a binary code, and a bit-compatible switch that is turned on when a brush contacts the switch contact. Is provided at a predetermined position, and an on / off signal of each detection switch when the zoom ring is rotated is output as a binary code (zoom position information).

However, in this device, for example, when the zoom position information is expressed by 4 bits, four detection switches are required. To detect a large number of zoom positions, too many switch contacts are required. For this reason, there were drawbacks that the cost was high and the reliability was poor due to many contact points.

Therefore, as an apparatus which has solved such a drawback, a pulse generator for generating a number of pulses corresponding to the amount of rotation of the zoom ring is provided, and the number of pulses from the pulse generator is counted to determine a predetermined position. One that recognizes the zoom position by detecting the moving distance from the camera has been realized.

[0005]

However, this device is
Since zoom position information does not exist in the zoom ring itself, for example, once zooming is performed and then the battery is replaced and the power is turned off, the zoom position information is lost.

If a backup power supply and a non-volatile memory are provided to prevent such a loss of the zoom position information, the cost increases. Therefore, in general, in order to recover the lost lens position information, when the battery is mounted again and the power is turned on, the current position is returned from the current position to the storage position while counting the number of pulses, and then moved again by the counted pulses. I have to.

However, in order to recover the lost zoom position information, it is necessary to return to the storage position without fail. Therefore, it takes time to set the zoom position, and a shutter chance may be missed. In addition, a similar problem has occurred in the case of lens movement for focus control.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a lens movement control device for performing a lens movement control while counting and storing a movement distance from a predetermined position, which is lost by turning off a power supply. The present invention is to enable quick recovery of the obtained lens position information with an inexpensive configuration.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a lens movement control apparatus for performing lens movement control while counting and storing a movement distance from a predetermined position. And a cylinder that is engaged with the lens barrel by a cam mechanism and moves the lens barrel in the optical axis direction by a rotation operation, and generates a number of pulses corresponding to the rotation amount of the cylinder as lens movement amount information. A pulse generating means, a switch provided at a predetermined position facing the peripheral surface of the cylindrical body, and a switch provided at the peripheral surface of the cylindrical body, rotating with the rotation of the cylindrical body and facing the switch. A short and long section for turning on the switch when the switch is moved to a position where the switch is turned on; a pulse generated by the pulse generating means during the rotation of the cylinder when the power is turned on; / Off credit On the basis of the change situation, and a lens position data recovery means for recovering the lens position data lost by the previous power-off.

[0010]

Now, for example, in response to the operation of the zoom button, the cylinder is rotated and the lens barrel and the lens are moved to perform zooming, and then the button is operated to perform the release. Assume that the batteries have been exhausted and the batteries have been replaced.

In such a case, the zoom position data held (stored) in a register or the like has been lost by turning off the power. Then, the lens position data recovery means rotates the cylinder, and based on the pulse generated by the pulse generation means at the time of rotation and the changing state of the switch ON / OFF signal, the lens position data lost by the power OFF. To recover.

[0012]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of an electronic camera equipped with a lens movement control device according to an embodiment of the present invention. In front of the camera, a photographing lens 1, a flash light emission window 2, a finder 3, and a light emitting device for distance measurement are provided. A window 4, a light-receiving window 5 for distance measurement, a light-receiving window 6 for photometry, and a self-timer LED 7 indicating that a self-timer mode is being set are arranged. A main switch button B1, a shutter release button B2, and a zoom button B3 are provided on the upper surface of the camera. Lens barrel 8
Is configured to advance and retreat in the optical axis direction in accordance with a change in the focal length, and is in a housed state in the figure. When the main switch is turned on by operating the main switch button B1, the lens barrel 8 automatically raises (projects) from the retracted state to the wide end position, and the main switch button B1 is operated when the main switch is on. It is configured to automatically collapse when turned off.

FIG. 2 is a perspective view of the lens movement control device. A lens barrel 8 holding the photographing lens 1 is inserted into a fixed barrel 9 and a rotating barrel 10. The fixed body 9 is fixed to the main body, and a plurality of elongated guide holes 9a are formed at predetermined intervals in the axial direction. The rotating drum 10 is rotatable in the circumferential direction, and the movement in the optical axis direction is restricted by a regulating member (not shown). A gear 10a and a plurality of obliquely elongated cam holes 10b are formed in the rotating drum 10, and a pin 8a formed in the lens barrel 8 has a guide hole 9a formed in the lens barrel 8 in the cam hole 10b. Are engaged through. When the rotation of the zoom motor M is transmitted to the gear 10a via the gear 11, and the rotating body 10 rotates, the lens barrel 8 moves forward and backward in the optical axis direction by the action of the pins 8a, the guide holes 9a, and the cam holes 10b. Then, the movement (zooming) of the photographing lens 1 is performed.

A gear 12 is engaged with the gear 11, and the gear 1
A disk 13 is connected to 2. A plurality of holes 13a are formed in the disk 13, and when the disk 13 rotates during zooming, the holes 13a are detected by the photo interrupter 14. Since this detection signal is a pulse signal corresponding to the zooming amount, it is hereinafter referred to as a zoom pulse.

On the outer periphery of the rotary drum 10, elongated cams A and B projecting in the radial direction are provided (FIG. 3).
reference). Cam A is longer in the circumferential direction than cam B,
The distance between the cam A and the cam B is longer than the length of the cam A. A cam switch CSW is provided near the rotating body 10. The cam switch CSW has a fixed contact Pa made of a highly rigid metal and a movable contact Pb made of a flexible metal. The switch is turned on by being pushed to the fixed contact Pa side and contacting both contacts.

FIG. 3 is a front view of the lens movement control device.
Shown in The positions of D1, D2, D3, and D4 shown in FIG. 3 correspond to the retracted, wide, tele, and macro positions, respectively. Further, as shown by an arrow in FIG. 3, when the rotating body 10 rotates in the clockwise direction, the photographing lens 1 is extended in the optical axis direction (hereinafter, referred to as zoom-up), and when rotated in the opposite direction. The photographing lens 1 is retracted in the optical axis direction (hereinafter, referred to as zoom-down).

The on / off state of the cam switch CSW when zooming up and zooming down is as shown in FIG. That is, the on / off state of the cam switch CSW is reversed between the collapsed position (D1) and the macro position (D4), which are both ends of the lens movement area. Also, as shown in FIG. 4, the user can zoom to an arbitrary focal length only in the region between the wide position and the tele position, and in the region between the retracted position and the wide position, and between the tele position and the macro position. The position of the photographing lens 1 cannot be set in the area between them. That is, when the main switch is turned on, zooming is automatically performed from the retracted position to the wide end position at a stretch, and a photographing is enabled. When the macro mode is set, zooming is performed at a stretch to the macro position. The area between the collapsed position and the end of the cam A, the area between the end of the cam A and the cam B, the area between the start and the end of the cam B, and the area between the end of the cam B and the macro position To the regions E1, E2, E3, E
4, and the numbers of zoom pulses corresponding to the respective regions are a, b, c, and d, respectively.

FIG. 5 is a diagram showing an electric circuit configuration of the electronic camera.

This electronic camera is configured to control a series of photographing sequences with the CPU 50 as a core.
The CPU 50 includes a distance measuring circuit 51 for measuring a subject distance,
A photometric circuit 52 for measuring the brightness of the subject, a flash light emitting circuit 53 for charging a flash capacitor and emitting a flash, a battery E
A motor drive circuit 5 that drives and controls a regulator 54, a lens driving motor 55a (including a zoom motor M), a shutter driving motor 55b, and a film feeding motor 55c, which converts the voltage from the camera into a constant voltage and supplies it to the CPU 50.
5. Main switch SW provided for each button
1, zooming switch SW2, macro setting switch S
W3, the cam switch CSW, and the photo interrupter 14 are connected. Then, the CPU 50 determines various photographing conditions based on ON / OFF signals of various switches and signals from the distance measuring circuit 51 and the photometric circuit 52, and sends various signals to the EF circuit 53 and the motor drive circuit 55 according to the determination result. The control signal is output to execute the photographing process. Also, CPU
50 is a zoom pulse from the photo interrupter 14,
And lens movement control is performed based on the ON / OFF signal of the cam switch CSW.

Next, an operation of returning the lens barrel 8 to the retracted position in a state where the zoom position has been lost due to the detachment of the power supply battery or the like will be described with reference to FIG.

In this case, the CPU 50 sets the cam switch C
It is determined whether or not the SW is in the ON state (step F-1). When the cam switch CSW is turned on, that is, when the cam switch CSW is turned on by the cam A or the cam B, first, zoom-up is started (step F-2). It is not known at this time whether the cam switch CSW is turned on by the cam A or the cam B when the zoom-up operation is performed first. If the cam switch CSW is turned on by the cam A, the zoom-down operation is performed. If this occurs, it collides with a mechanical abutting member (not shown) formed further in the zoom-down direction than the collapsed position, and an excessive load is generated in the drive transmission system from the motor M to the lens barrel 8, causing gear loss or the like. This is because jumping of gears or the like occurs, and a state in which an overcurrent flows in the motor M is continued, which adversely affects the motor M.

Next, after the cam A or the cam B has passed the position of the cam switch CSW, it waits until the cam switch CSW is turned off (step F-).
3) Start zoom-down (step F-4).
If it is determined in step (F-1) that the cam switch CSW is in the off state, that is, it is determined that the cam switch CSW is not turned on by the cam A or the cam B, the above-described problem occurs. Since there is no possibility of occurrence, without going through steps (F-2) to (F-3),
Proceed to step (F-4).

After the zoom down is started in step (F-4), the camera waits for the cam switch CSW to turn on (step F-5), and counts the number of zoom pulses after the cam switch CSW starts to turn on. Is started (step F-6). Then, it is determined whether or not the count value of the zoom pulse has reached the number “a” corresponding to the area of the cam A (step F-7). As a result, if it has not reached the area of the cam A, it is determined whether or not the cam switch CSW has been turned off (step F-8).
If the SW has not turned off, the process returns to step (F-7). When the cam switch CSW is turned off, it means that the original zoom position is within the range of the area E3 (cam B) in FIG. 4 and has passed the starting point of the cam B due to the zoom down. Is stopped, the count value is reset (step F-9), and the process returns to step (F-5). If the original position is the position corresponding to the cam A, the cam switch SCW does not change to off in step (F-8).

If it is determined in step (F-7) that the count value of the zoom pulse has reached the area "a" of the cam A, it means that the lens barrel 8 has been returned to the retracted position. Therefore, the zoom-down operation is stopped (step F-1).
0), the number of zoom pulses "0" is set in the register Z for storing the zoom position (step F-11), and the processing is terminated.

Next, referring to FIG. 7, when the power is turned off in a state where the taking lens 1 is set at an arbitrary position in the lens moving area and the memory of the set lens position is lost,
An operation of reproducing the storage of the lens position and setting the photographing lens 1 at the position when the power is turned off will be described.

After zooming to the position where the cam switch CSW is ON, that is, the position of the area E1 corresponding to the cam A or the area E3 corresponding to the cam B shown in FIG. 4, the power supply battery is removed and the power supply battery is removed again. Take the case of loading.

In this case, it is unknown at present whether the region is the region E1 or E3, and if the zoom-down operation is performed in the case of the region E1, the collision with the mechanical abutting member occurs as described above. First, zoom-up is started (step F-21), and counting of zoom pulses is started (step F-22). Then, it waits until the cam switch CSW is turned off (step F-
23) The count of the zoom pulse is stopped from the time when the cam switch CSW is turned off, and the current count value is set in the register N (step F-24). This count value corresponds to the number of pulses for the region from the original position to the end of the cam A or the cam B.

Next, the zoom-down is started (step F-25), and it is confirmed that the cam switch CSW is turned on (step F-26). Then, the count of the zoom pulse is started when the cam switch CSW is turned on. (Step F-27). Then, it is determined whether or not the count value of the zoom pulse has reached the pulse number “a” for the area of the cam A (step F-28). As a result, if the pulse number “a” for the area of the cam A has not been reached, the cam switch CS
It is determined whether W has turned off (step F-2).
9). As a result, if it has not changed to off, the flow returns to step (F-28), and it is determined again whether or not the count value of the zoom pulse has reached the pulse number “a” for the area of the cam A.

On the other hand, when the cam switch CSW is turned off, it means that the power has been turned off when the original position is in the area E3, so that the zoom up is started to return to that position (step F-30). . Then, it waits for the cam switch CSW to be turned on (step F-31), and starts counting zoom pulses from the time the cam switch CSW is turned on (step F-32). Then, it is determined whether or not the counted zoom pulse becomes a value {c- (N)} obtained by subtracting the number of pulses in the register N from the number of pulses “c” for the area E3 (step F-33). As a result, when the above subtraction value is reached, it means that the camera has returned to the original position, and the zooming is stopped (step F).
-34). Then, the above subtraction value is added to the number of pulses (a + b) from the retracted position to the area E3, and the addition result {a + b + c- (N)} is set in the register Z as zoom position information (step F-). 35), end. If it is determined in step (F-28) that the count value of the zoom pulse has reached the pulse number "a" for the area of the cam A, the power supply is turned off when the zoom lens is in the retracted position. Since this means that the camera has returned to the position, the zoom-down is stopped (step F-36), "0" is set in the register Z as zoom position information (step F-35), and the process ends. In other words, in this embodiment, after the battery is removed from the position between the wide end and the tele end or at the macro position, when the battery is loaded, the battery is returned to the position where the battery was removed, and other areas are detected. If so, it is returned to the storage position.

Note that when the cam switch CSW is off,
That is, after zooming to the position of the area E2 or area E4 in FIG. 4, the power is turned off, and the power is turned on again. In order to prevent a malfunction from occurring, a zoom-down operation is performed first, and a count of zoom pulses is started. And the cam switch CSW
Is turned on, the count of the zoom pulse is stopped from the time when the cam switch CSW is turned on, and the count value is compared with the pulse number “d” corresponding to the area E4 stored in advance, (1) When the count value is larger than the pulse number "d", it is determined that the lens barrel 8 is located in the area E2, and the count value is set in a register. By driving the lens barrel 8 by the count value stored in the register after the power is turned off, it is possible to return to the position where the power is turned off.

(2) When the count value is equal to or smaller than the pulse number "d", the lens barrel 8 is set in the region E2 or the region E2.
4 cannot be determined, the count value is set in the register N, zoom-down is performed as it is, and the cam switch CSW is turned on in the area E3.
Is determined to be longer than the pulse number “c” corresponding to the area E3, and if the cam switch CSW continues to be turned on even when the pulse number “c” corresponding to the area E3 is exceeded, it is located in the area E1. And the pulse number “c” corresponding to the area E3
Is exceeded and the cam switch CSW is turned off, it is determined that it is located in the area E2. Subsequently, zoom-up is performed, and zoom-in is performed by the count value stored in the register N from the point in time when the cam switch CSW is switched from on to off, whereby it is possible to return to the power-off state.

As described above, since the zoom position data at the time of turning off the power is recovered by using the on / off state of the cam switch CSW based on the cams A and B, the zoom position returns to the retracted position (initial position). Since there is no necessity and the amount of movement is small, zoom position data at the time of power-off can be quickly recovered. In addition, the absolute position of the zoom
There is no need to attach a position detection device , store zoom position data in a non-volatile memory, or back up with a separate power supply, so that there is no increase in cost.

The present invention is not limited to the above embodiment, but can be applied to, for example, a case where data of a lens position moved for focus control is recovered.

As an application example, in this embodiment, the number of pulses in the area E1 corresponding to the cam A, the area E3 corresponding to the cam B, the area E2 without the cam, and the pulse E4 are stored in the CPU 50, and the shape of the cam is The area of the cam B is shorter than the area of the cam A, and the area E4 is shorter than the area E2 in the area without the cam. However, the present invention is not limited to this. In the area without a cam, the area E4 is shorter than the area E2. In the area without the cam, the area B4 is shorter than the area E2. The number of pulses may be simply stored in the CPU 50. (2) Three cams are provided and the on / off of the cam switch is formed as shown in FIG. 8, so that the length of the cam in the circumferential direction is shortened in the order of the area of cam A> cam B> cam C. And the length on the circumference of the area without the cam is D>E>
G is set so as to be sequentially shorter, and the length on the circumference of the cam is cam A> cam B> cam C, and the length on the circumference of the area without the cam is D>E> G. And the number of pulses in the cam A area are stored in the CPU 50.

In addition, although various modifications can be considered, basically, the area of the cam section at one end is formed longer than the area of the other cam section in the lens moving area, and It is a necessary condition that the number of pulses corresponding to the cam section is stored, and that different signals are output at both ends in the lens movement area.

[0037]

As described above, according to the present invention,
In a lens movement control device that performs lens movement control while counting and storing a movement distance from a predetermined position, lens position information that has disappeared due to power-off can be quickly recovered with an inexpensive configuration.

[Brief description of the drawings]

FIG. 1 is a perspective view of an electronic camera equipped with a lens movement control device according to one embodiment of the present invention.

FIG. 2 is a perspective view of a lens movement control device.

FIG. 3 is a front view of the lens movement control device of FIG. 2;

FIG. 4 is a time chart showing an on / off state of a cam switch during lens movement control by the lens movement control device;

FIG. 5 is a diagram showing an electric circuit configuration of the electronic camera of FIG. 1;

FIG. 6 is a flowchart showing a control operation when returning to a retracted position.

FIG. 7 is a time chart showing a control operation when restoring zoom position data when the power is turned off.

FIG. 8 is a time chart showing an on / off state of a cam switch during lens movement control by a lens movement control device according to another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shooting lens 8 Lens barrel 10 Rotating barrel 14 Photo interrupter 50 CPU A Cam B Cam CSW Cam switch

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-85810 (JP, A) JP-A-3-2707 (JP, A) JP-A-58-90622 (JP, A) JP-A-2- 51020 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G02B 7/08

Claims (1)

(57) [Claims] In a lens movement control device for performing lens movement control while counting and storing a movement distance from a predetermined position, a lens barrel holding a lens, and a lens mechanism engaged with the lens barrel by a cam mechanism to rotate the lens. A cylindrical body for moving the lens barrel in the optical axis direction, pulse generating means for generating a number of pulses corresponding to the amount of rotation of the cylindrical body as lens movement amount information, and a predetermined face facing the peripheral surface of the cylindrical body And a long and short switch provided on the peripheral surface of the cylinder, turning on the switch when the cylinder is rotated and moving the switch to a position facing the switch. When the power is turned on, the cylinder rotates when the power is turned on. Based on a pulse generated by the pulse generating means at the time of rotation and a change state of the on / off signal of the switch, a previous power off is performed. Disappeared by And a lens position data recovery unit for recovering the lens position data.