JPH052204A - Power focus device - Google Patents

Abstract

(57) [Summary] [Objective] The operability at the time of distance adjustment is improved by setting the drive amount or drive speed of the focusing optical system according to the speed of the distance operation ring of the power focus device. A power focus device is provided with a means for detecting a rotation speed of a distance operation ring, and a ratio (distance adjustment ring rotation amount) / (focusing optical system drive) is set according to a rotation speed of the distance operation ring. Amount) or (distance adjustment ring rotation speed) /
A drive amount setting means or a drive speed setting means capable of changing the (driving speed of the focusing optical system) and setting the driving amount or driving speed of the focusing optical system is provided. As a result, for example, when the distance operation ring is rotated faster, the driving amount of the focusing optical system becomes larger or faster, and when the distance operation ring is rotated later, the driving amount of the focusing optical system becomes smaller or slower. Become. Therefore, for example, in distance adjustment, optimum driving is performed in accordance with coarse movement or fine movement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power focus device for converting a manual distance adjustment operation of an interchangeable lens barrel into a drive of a focusing optical system by a motor, and a technique for improving the operability of the distance adjustment operation. Regarding

[0002]

2. Description of the Related Art In recent years, cameras and interchangeable lens barrels having an autofocus (AF) function have been widely used. These are for automatically focusing by driving a focusing optical system by a camera body or a motor provided in the lens barrel based on the output from the focus detection device. The AF function is a very convenient function in normal shooting, but when manual focusing (MF) is required, such as when intentionally performing focus operations or when shooting a subject that is difficult to focus on. There are many. Considering such a shooting situation, it is desirable that the AF operation and the MF operation are compatible with the same operability even in a camera having an autofocus (AF) function. From this point,
Generally, a camera is provided in the camera body or the lens barrel to provide a driving force transmission system between the focusing optical system and the driving motor, and by switching the clutch, both AF operation and MF operation are possible. It is popular.

However, in the camera system having the above-described structure, since the clutch switching operation is required, the switching cannot be done in time and the shooting opportunity is missed.
Alternatively, there are problems such as a time lag for switching the clutch, an impact at the time of switching the clutch, and a sound.

On the other hand, an AF driving motor is used, and the focusing optical system is driven by the motor even during MF operation.
A so-called power focus (PF) function in which the clutch mechanism is abolished has been devised. As a typical power focus device, two button switches for selecting the driving direction of the focusing optical system are provided, and when the photographer selects the driving direction of the focusing optical system necessary for focusing with this switch, Of a type that drives the focusing optical system at a predetermined speed,
Alternatively, there is a system in which a dial type switch is provided and the drive direction and drive speed of the focusing optical system are set by the rotation direction of this switch and the rotation amount from the neutral position, respectively. However, in addition to the drawbacks such as delicate focus adjustment being impossible due to poor stop characteristics, these are remarkably different from the conventional operation method of the distance operation ring, and there is a disadvantage that operability is poor.

On the other hand, in Japanese Patent Laid-Open No. 63-89826, the conventional direction, rotation amount, and rotation speed of the distance operation ring are detected, and based on this, the driving direction, driving amount, and driving of the focusing optical system are detected. A method of setting the speed is disclosed. According to this method, a power focus device that is relatively close to the conventional MF operation feeling can be obtained.

[0006]

However, in the power focus device having the above-described structure, the driving of the focusing optical system by power focus is merely the faithful reproduction of the conventional MF operation by the motor. The advantage of driving the focusing optical system by a motor has not been fully utilized. Therefore, the drawbacks that existed during the conventional MF operation,
For example, the so-called coarse movement for moving the focusing optical system to the in-focus position is slow and troublesome, and the focus adjustment in the vicinity of the in-focus position, so-called fine movement, is difficult to be solved.

Although an embodiment in which the drive speed of the focusing optical system is changed by the switch operation is also disclosed, it is very difficult to change the drive speed by the switch operation in a series of distance adjusting operations. , Lacks in practicality.

Therefore, it is an object of the present invention to drive the focusing optical system according to the intention of the operator, for example, whether the operator intends to perform a coarse movement or a fine movement. The purpose is to enable automatic control of the speed and thus greatly improve the operability of the power zoom device.

[0009]

In order to achieve the above object, a power focus device according to the present invention comprises means for detecting the rotation speed of a distance adjusting ring, and means for detecting the rotation speed of the distance adjusting ring. , Ratio (distance adjustment ring rotation amount) /
Drive amount setting means or drive for setting the drive amount or drive speed of the focusing optical system by changing (driving amount of focusing optical system) or ratio (distance adjusting ring rotation speed) / (driving speed of focusing optical system) And speed setting means.

[0010]

In the above structure, for example, when it is detected that the distance adjusting ring is rotated faster than a predetermined rotation speed, the drive amount setting means or the drive speed setting means,
The drive amount or drive speed of the focusing optical system is set so that the ratio becomes smaller than usual. On the other hand, when it is detected that the distance adjusting ring is rotated slower than another predetermined rotation speed, the drive amount setting means or the drive speed setting means causes the focusing optical system to make the ratio larger than usual. Set the drive amount or drive speed of. Therefore, when the distance adjusting ring is rotated quickly, the focusing optical system is driven more or faster than usual, and when the distance adjusting ring is rotated slowly,
Focusing optics are driven less than normal or slower. Therefore, in the case of coarse movement for bringing the focusing optical system to the focusing position, that is, when the distance adjusting ring is rotated quickly, the focusing optical system can be brought closer to the focusing position, for example, faster.
Further, in the case of fine adjustment of the focus in the vicinity of the in-focus position, that is, when the distance adjusting ring is rotated slowly, the fine adjustment is performed more easily because the focusing optical system moves less or slower. In this case, it is automatically determined whether the operator intends to perform coarse movement or fine movement, and the drive amount or drive speed of the focusing optical system is automatically adjusted, which is extremely convenient. A good power focus device is realized.

[0011]

1 shows the schematic construction of a lens equipped with a power focus device according to a first embodiment of the present invention.
The lens in the figure shows a case of a photographing lens for a camera as an example, and the lens barrel 1, the distance adjusting ring 2,
Pulse generator 3, optical systems L1, L2, L3, speed detecting means 4, rotation amount detecting means 5, rotation direction detecting means 6, speed determining means 10, speed setting means 7, drive amount setting means, drive direction setting means 9 , Drive control means 11, drive motor 12,
The second pulse generating means 13 and the like are used. Then, such a lens barrel 1 is attached to a camera body (not shown) by, for example, a bayonet mount 1a.

Of the optical systems L1, L2 and L3, L2 constitutes a focusing optical system, which is constructed so as to be movable in the optical axis direction for focusing operation. The distance adjusting ring 2 is provided on the lens barrel 1 so as to be rotatable from the outside about the optical axis.
A pulse generator 3 is provided on the distance adjusting ring 2,
The number of pulses generated is proportional to the rotation angle of the distance adjusting ring 2. The pulse generator 3 is composed of, for example, a rotary encoder provided inside the distance adjusting ring 2.

The output of the pulse generator 3 is connected to a speed detecting means 4, a rotation amount detecting means 5, and a rotation direction detecting means 6, respectively. The speed detecting means 4 is the pulse generator 3
The rotation speed V of the distance adjusting ring is detected by counting the pulses generated by the pulse generator for a predetermined time. The rotation amount detecting means 5 detects the rotation angle or the rotation amount L ₀ of the distance adjusting ring by counting the number of pulses generated by the pulse generator 3. Further, the rotation direction detection device 6 receives two types of phase-shifted pulses from the pulse generation device 3, and detects the rotation direction by detecting the phase shift of these pulses. In order to detect such a rotation direction, the encoder of the pulse generator 3 is provided with, for example, two types of aperture rows having different phases on the rotary ring mounted inside the distance adjusting ring 2, and the photo row is provided from these aperture rows. A two-phase pulse is generated by the interrupter.

A rotation speed discriminating means 10 is connected to the output of the rotation speed detecting means 4 and compares the rotation speed detected by the rotation speed detecting means 4 with a reference value to make a rotation speed V _{0 of the} distance adjusting ring. And a reference value is output. The drive speed setting means 7 sets the drive speed of the focusing optical system based on the signal from the rotation speed determination means 10 and the signal directly input from the rotation speed detection means 4. is there. Further, the drive amount setting means 8 is connected to the rotation amount detecting means 5,
This outputs a drive amount setting signal according to the rotation angle of the distance adjusting ring. Further, the drive direction setting means 9 connected to the rotation direction detecting means 6 outputs a signal indicating the drive direction of the focusing optical system according to the rotation direction of the distance adjusting ring.

Further, the drive control means 11 includes the drive speed setting means 7, the drive amount setting means 8 and the drive direction setting means 9.
The drive signal is applied to the drive motor 12 for moving the focusing optical system L2 based on each setting signal from The focusing optical system L2 includes the second pulse generator 1
3 is provided, and the actual drive speed and drive amount of the focusing optical system L2 are fed back to the drive control means 11.

In the apparatus having the above-mentioned structure, the rotational speed discriminating means 10 has two speeds V in advance.
_H , V _L (V _H > V _L ) are stored. When the operator rotates the distance adjusting ring 2, the rotation speed detecting means 4 detects the rotation speed V ₀ of the distance adjusting ring 2 and inputs it to the rotation speed discriminating means 10. The rotation speed determination means 10 determines the magnitude relationship between the rotation speed V ₀ of the distance operation ring 2 and the reference values V _H , _VL , and inputs a signal according to the determination result to the speed setting means 7. The drive speed setting means 7 determines the drive speed V of the focusing optical system on the basis of the signal indicating the determination result and the signal corresponding to the rotation speed V ₀ of the distance adjusting ring 2 directly input from the rotation speed detection means 4. Determine as follows. When V ₀ > V _H V ₀ / V <t _V V _H > V ₀ > V _L When V ₀ / V = t _V V _L > V ₀ When V ₀ / V> t _V where t _V is The relationship between the distance ring rotation speed and the moving speed of the focusing optical system during the normal MF (manual focus) operation is set to be the same. Accordingly, by appropriately setting the reference speeds V _H and _VL , power focusing with the same sensation as during MF operation is performed near the normally used distance ring rotation speed, and the distance ring is rotated faster than usual. Sometimes, the focusing optics can be moved faster, and when the distance ring is rotated slower than usual, the focusing optics can be moved slower.

The rotation amount L ₀ detected by the rotation amount detecting means 5
Is transmitted to the drive amount setting means 8 of the focusing optical system, and the drive amount L is determined as follows. L ₀ / L = t ₁ Here, t ₁ is the same as the relationship between the distance ring rotation amount and the movement amount of the focusing optical system during the normal MF operation.

The rotation direction detected by the rotation direction detection means 6 is transmitted to the drive direction setting means 9 of the focusing optical system, and a signal representing the drive direction set in the predetermined direction is output.

Signals indicating the driving speed, the driving amount, and the driving direction set as described above are input to the drive control means 11, and the driving means 11 drives the motor 12 according to each setting, and the focusing optical system L2. Is moved in the optical axis direction. In this case, the driving speed, the driving amount, etc. of the focusing optical system L2 are set to the second value.
The pulse is fed back to the drive control means 11 by the pulse generation means 13.

FIG. 2 shows a schematic structure of a lens equipped with a power zoom device according to a second embodiment of the present invention. In the lens of FIG. 2, the speed setting means 7 in FIG. 1 is removed, and instead the output of the speed determination means 10 is input to the drive amount setting means 8 to adjust the focusing optical system according to the rotation speed of the distance adjusting ring 2. The drive amount is adjusted. The other parts may be the same as those of the apparatus of FIG. 1, and the same parts are denoted by the same reference numerals.

In the apparatus of FIG. 2, the rotation speed discriminating means 10 stores, for example, two kinds of reference speeds V _H and V _L (V _H > V _L ) in advance, as in the case of FIG.
Rotational speed V ₀ of the distance operation ring 2 detected by the speed detection means 4
Then, the magnitude relation between these reference velocities V _H and V _L is discriminated, and a signal indicating the magnitude relation is inputted to the drive amount setting means 8. On the other hand, the rotation amount L ₀ detected by the rotation amount detecting means 5 is also directly transmitted to the drive amount setting means 8. In the drive amount setting means 8, the drive amount L of the focusing optical system is determined as follows. If V ₀ > V _H , then L ₀ / L <t ₁ V _H > V ₀ > V _L , then L ₀ / L = t ₁ V _L > V ₀ , then L ₀ / L> t ₁ where , T ₁ are the same as the relationship between the distance ring rotation amount and the movement amount of the focusing optical system during the normal MF operation. Accordingly, by appropriately setting the reference speeds V _H and _VL , power focusing with the same sensation as during MF operation is performed near the normally used distance ring rotation speed, and the distance ring is rotated faster than usual. In this case, the focusing optical system is moved more, and when the distance ring is rotated slower than usual, the focusing optical system can be moved less.

The rotation direction detected by the rotation direction detecting means 6 is transmitted to the drive direction setting means 9 of the focusing optical system, and the drive direction is set to a predetermined direction, as in the case of FIG. .

The drive motor 12 is driven by the drive control means 11 in accordance with the drive amount and drive direction thus set, and the focusing optical system L2 is moved in the optical axis direction.

In the above description, the rotation speed discriminating means 10 determines the rotation speed of the distance adjusting ring 2 as two reference values V _H ,
Although the drive speed or drive amount of the focusing optical system is set in three stages by using V _L to determine the speed in three stages, the present invention is not limited to this, and it is also possible to set in any stage. It is also possible to continuously set the drive speed or drive amount of the focusing optical system according to the rotation speed of the distance adjusting ring.
Further, the ratios t ₁ and t _V described above can also be set to arbitrary values. Further, a pulse proportional to the rotation angle of the distance adjusting ring was used to detect the rotation direction, rotation speed, and rotation amount of the distance adjusting ring, but these detection methods are not limited to this, and an optimal method can be used as appropriate. Is.

[0025]

As described above, according to the present invention, when the driving amount or driving speed of the focusing optical system depends on the rotation speed of the distance adjusting ring, for example, when the distance adjusting ring is turned fast, the focusing optical system is rotated. Is driven more or faster than usual, and when the distance adjusting ring is turned slower, the focusing optical system is driven less or slower than usual. Therefore, when the coarse movement for moving the focusing optical system to the focusing position, that is, when the distance adjusting ring is quickly rotated, the focusing optical system can be brought closer to the focusing position faster or a small amount of operation of the distance adjusting ring is performed. Can be used to bring the focus position closer to the in-focus position.On the other hand, when finely adjusting the focus in the vicinity of the in-focus position, that is, when rotating the distance adjustment ring slowly, the focusing optical system moves less or moves slowly, so more precise fine adjustment is possible. Can be done easily. Moreover, in this case, whether the distance adjustment is a coarse movement or a fine movement is automatically determined, and the driving amount or the driving speed of the focusing optical system is automatically adjusted accordingly, so that the power is extremely convenient. A focus device is realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a lens including a power focusing device according to a first example of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a lens including a power focus device according to another embodiment of the present invention.

[Explanation of symbols]

1 lens barrel 2 distance adjustment ring 3 pulse generator 4 Speed detection means 5 Rotation amount detection means 6 Rotation direction detection means 7 Speed setting means 8 Drive amount setting means 9 Drive direction setting means 10 Speed discrimination means 11 Drive control means 12 Drive motor 13 Second pulse generating means 1a bayonet mount L2 focusing optics

Claims (8)

[Claims] 1. A distance adjusting ring that is manually rotated, a driving device that drives a focusing optical system in an optical axis direction, a rotation direction detecting unit that detects a rotation direction of the distance adjusting ring, and the distance adjusting ring. An amount of rotation detecting means for detecting the amount of rotation of the distance adjusting ring, a rotating speed detecting means for detecting the rotating speed of the distance adjusting ring, and a means for setting the drive direction of the drive device based on the detection result of the rotating direction detecting means. A drive amount setting means for setting a drive amount of the drive device based on a detection result of the rotation amount detecting means, and a drive control device for controlling the drive device according to the set drive direction and drive amount. The means sets the drive amount by changing the ratio (distance adjusting ring rotation amount) / (focusing optical system drive amount) according to the rotation speed of the distance adjusting ring detected by the rotation speed detecting means. A power focus device characterized in that. 2. A distance adjusting ring that is manually rotated, a drive device that drives a focusing optical system in the optical axis direction, a rotation direction detecting unit that detects a rotation direction of the distance adjusting ring, and the distance adjusting ring. An amount of rotation detecting means for detecting the amount of rotation of the distance adjusting ring, a rotating speed detecting means for detecting the rotating speed of the distance adjusting ring, and a means for setting the drive direction of the drive device based on the detection result of the rotating direction detecting means. Means for setting the drive amount of the drive device based on the detection result of the rotation amount detection means, and means for setting the drive speed of the drive device based on the detection result of the rotation speed detection means, And a means for controlling the drive of the drive device according to the drive direction, the drive amount, and the drive speed,
The drive speed setting means changes the ratio (distance adjusting ring rotation speed) / (driving speed of the focusing optical system) according to the magnitude of the rotation speed of the distance adjusting ring detected by the rotation speed detecting means. A power focus device characterized by setting a driving speed. 3. The ratio is continuously changed according to the magnitude of the rotation speed detected by the rotation speed detecting means, and when the rotation speed is high, the ratio is small, and when the rotation speed is low, the ratio is small. The power focus device according to claim 1, wherein the drive amount is set so that the ratio becomes large. 4. The ratio is continuously changed according to the rotation speed detected by the rotation speed detecting means, and the ratio is small when the rotation speed is high, and the ratio is low when the rotation speed is low. The power focus device according to claim 2, wherein the drive speed is set to be large. 5. The rotation speed detected by the rotation speed detecting means is adjusted so that the drive amount is smaller than the ratio when the rotation speed detected by the rotation speed detecting means is equal to or higher than a first predetermined speed. A second speed smaller than the first predetermined speed
2. When the speed is equal to or lower than a predetermined speed, the drive amount is set so that the ratio becomes larger than usual.
The power focus device described in 1. 6. The rotation speed detected by the rotation speed detection means is set so that the ratio of the drive speed becomes smaller than usual when the rotation speed detected by the rotation speed detection means is equal to or higher than a first predetermined speed. The power focus device according to claim 2, wherein the drive speed is set so that the ratio becomes higher than normal when the speed is lower than a second predetermined speed that is lower than the first predetermined speed. 7. The rotation amount and the rotation speed of the distance adjusting ring are detected from a pulse signal generated by a number proportional to the rotation angle of the distance adjusting ring. Power focus device. 8. The power focus device according to claim 1, wherein the rotation direction of the distance adjusting ring is detected from a two-phase pulse signal generated in proportion to a rotation angle of the distance adjusting ring.