JPH0728113A - Automatic focusing camera - Google Patents

Abstract

PURPOSE:To enhance the operating easiness by allowing the drive to continue only by separation of the hand even in case it touches a lens barrel undeliberately by furnishing a means to change over a photographing lens driving means into the intermittent drive. CONSTITUTION:When a focusing motor 9 lying in the reset position is put in regular rotating and advances in the optical axis direction (to the left), the first timer is started to commence counting of the drive pulses. If judgement is such that the specified number of pulses is not attained within a certain time, changing-over into the pulse drive (intermittent) and the focusing motor 9 is driven. According to the arrangement, the motor 9 is changed over into the intermittent drive in case the camera user has by mistake stopped the motion of a photographing lens 1 during focusing, or under the focusing return, so that it is free from risk of heat emission of the motor 9 because of flowing of a lock current, allows movement of the lens 2, and enables the focusing movement and the returning motion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an autofocus camera which moves an image pickup lens in the optical axis direction.

[0002]

2. Description of the Related Art In a conventional autofocus camera of this type, when the photographing lens does not reach a predetermined position within a predetermined time,
The sequence has been stopped by stopping the power supply to the lens driving means.

[0003]

In a conventional camera in which a lens barrel projects from a camera cover to perform a focusing or zooming operation, when a photographer carelessly touches the lens barrel, the lens is not moved within a predetermined time. When the lens barrel does not reach the predetermined position, the driving of the lens barrel is stopped, and there is a drawback that not only shooting is not possible but also it is not possible to recover without complicated operation. Further, if the energization is continued without performing the stop control, the motor may generate abnormal heat and burn.

The present invention has been made in view of the above problems, and when the photographer carelessly touches the lens barrel,
Even when the lens barrel does not reach a predetermined position within a predetermined time, it is possible to continue driving by releasing the touched hand, improve operability, and prevent abnormal heat generation of the motor.

[0005]

In order to achieve this object, an autofocus camera according to the present invention comprises an imaging lens, an imaging lens driving means for moving the imaging lens to a predetermined position in the optical axis direction, and an imaging lens. The imaging lens position detecting means for detecting the position in the optical axis direction, the starting operation switch for instructing the imaging lens driving means to move the imaging lens, the detection output of the imaging lens position detecting means, and the state of the starting operation switch are used to determine the imaging lens. And a control means for controlling the driving means,
When the photographing lens does not reach the predetermined position within a predetermined time after operating the start-up operation switch, the control means is configured to switch the photographing lens driving means to the intermittent drive to move the photographing lens.

[0006]

In the autofocus camera having the above structure, the control means switches the image pickup lens drive means to the intermittent drive and moves the image pickup lens when the predetermined position is not reached within a predetermined time after the start operation switch is operated. Therefore, even if the photographer touches the lens barrel, the drive source can continue to be energized, and heat is not generated. Therefore, even if the photographer touches his / her hand and stops, the drive is continued if he / she removes his / her hand from the lens barrel, and a complicated restoration operation becomes unnecessary.

[0007]

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

FIG. 1 is a block connection diagram showing an embodiment of an autofocus camera according to the present invention.

In FIG. 1, an image pickup lens 1 is composed of a single focus lens or a variable power lens having a plurality of lens groups,
It is held by the lens frame 5. A guide hole 5a and a female screw hole 5b are formed at the upper end of the lens frame 5. The guide hole 5a guides the movement of the lens frame 5 in the optical axis direction (left and right direction in FIG. 1) by sliding with the rod 4, and the female screw hole 5b is screwed with the feed screw 3 to allow the lens frame 5 to move. Are driven in the optical axis direction. On the side of the photographic film 16 of the lens frame 5, a shutter 2 also serving as a diaphragm is provided, and a sliding brush 6 is attached and fixed to the lower end portion. The lens frame 5, the diaphragm / shutter 2 and the sliding brush 6 are integrally moved in the optical axis direction.

A gear 3a is fixed to the right end of the feed screw 3 coaxially with the feed screw 3. The gear 3a is screwed with the pinion gear 9a, and the pinion gear 9a is fixed to the focusing motor 9b of the focusing motor 9. Therefore, when the focusing motor 9 rotates, the feed screw 3 is rotationally driven to move the lens frame 5 in the optical axis direction. The rotation of the lens frame 5 is controlled by the CPU circuit 14 via the focusing motor driver 10 and the lens position command means 17. The rotation amount of the lens frame 5 is detected by a combination of the rotary plate 8 attached to the focusing motor 9b and the photo interrupter 7, and is supplied to the CPU circuit 14 as an output pulse signal of the photo interrupter 7.

The sliding brush 6 attached to the lower end of the lens frame 5 forms a sliding switch S3 together with the conductor patterns 6a and 6b. That is, the conductor pattern 6a forms a mover of the sliding switch S3, and the conductor patterns 6a and 6a
b forms the stator of the sliding switch S3. The conductor patterns 6a and 6b have different lengths, and are divided into a region A where the conductor pattern 6a contacts both conductor patterns 6a and 6b, and a region B where only the conductor pattern 6b contacts.

From the sliding switch S3, when the sliding brush 6 is in the area A, an "L" level signal is output from the CPU circuit 1.
4 is output, and when the sliding brush 6 is in the area B, "
An H "level signal is output to the CPU circuit 14. This allows the CPU circuit 14 to detect whether the lens frame 5 is in the area A or the area B. Focusing the lens frame 5 and the like. In the reset state before the operation, the sliding brush 6 is placed in the area B. Since the sliding brush 6 is moved to the area A by the forward rotation of the focusing motor 9, the CPU circuit 14 outputs the output pulse of the photo interrupter 7. The normal operation is to start counting the signal and stop the focusing motor 9 when the signal reaches a predetermined value.

The exposure control means 11 controls the aperture / shutter 2 by a control signal from the CPU circuit 14 based on the photometric value from the photometric means 12. The distance measuring means 13 measures the subject distance and supplies a distance measuring signal to the CPU circuit 14. The CPU circuit 14 calculates the in-focus position of the imaging lens 1 based on this distance measurement signal, and the lens position command means 17
Then, the focusing motor 9 is rotated in the normal direction via the focusing motor driver 10. As a result, the lens frame 5 starts moving leftward in FIG. CPU circuit 14
Stops the rotation of the focusing motor 9 when the count value of the output pulse signal of the photo interrupter 7 matches a predetermined value.

The switch S1 connected to the CPU circuit 14 is a half-press switch for instructing the photometry by the photometry means 12 and the distance measurement by the distance measurement means 13. The switch S2 is a full-press switch for instructing rotation control of the focusing motor 9 and exposure (exposure of the photographic film 16) by the shutter 2 that also serves as the diaphragm. Both are operation switches pressed by the photographer. The film feeding means 15 is
Controlled by the CPU circuit 14, shooting (shooting film 16
After the exposure), the photographing film 16 is wound up one frame to prepare for the next photographing, and when the photographing of all the photographing films 16 is finished, it is rewound.

Next, the operation of the CPU circuit 14 will be described with reference to the flowchart of FIG.

In step S101, it is determined whether the half-press switch S1 is on or off. If the switch S1 is on, photometry and distance measurement are performed in steps S102 and S103, and focusing calculation is performed based on the distance measurement value (step S104). , The number of pulses (N) corresponding to the lens stop position is determined (step S105). Step S1
At 06, the exposure value is calculated based on the photometric result. In step S107, it is determined whether the full-press switch S2 is on or off.

If the switch S2 is off, step S1
At 09, it is determined whether the switch S1 is on or off. If the switch S1 is on, the process returns to step S107 to switch S1.
If 1 is off, the program ends. Step S10
When it is determined in step 7 that the switch S2 is on, the focusing motor 9 is normally rotated in step S108. In step S110, the switch S3 is "L" or "H".
Determine the output.

When the focusing motor 9 in the reset position advances in the optical axis direction (to the left) due to the normal rotation of the focusing motor 9, the output of the switch S3 changes from "H" to "L". After waiting for the output of the switch S3 to become "L", the process proceeds to step S111 to start the first timer. Further, in step S112, counting of drive pulses is started. In step S113, it is determined whether the timer started in step S111 has timed out. If the time is not up, it is determined in step S114 whether the pulse count has reached the number of pulses (N) determined in step S105. That is, step S113 and step S1
In 14, when it is determined that the predetermined number of pulses (N) is not reached within the predetermined time, the process proceeds to step S115. When it is determined in step S114 that the predetermined number of pulses (N) has been reached within the predetermined time, the process proceeds to step S117.

In step S115, the focusing motor 9 is driven by switching to pulse driving (intermittent driving).
The pulse count is a predetermined number of pulses (N) due to pulse drive
Is reached (step S116), and when a predetermined pulse is reached, the process proceeds to step S117. When it is determined that the predetermined number of pulses (N) is not reached, step S11
Returning to step 5, the intermittent driving of the focusing motor 9 is repeated.

In step S117, since the imaging lens 1 has reached the in-focus position, the focusing motor 9 is deenergized. In step S118, step S1
The aperture / shutter 2 is driven based on the exposure value determined in 06 to perform the exposure operation. In step S119, the focusing motor 9 is rotated in the reverse direction in order to drive the imaging lens 1 that has been driven to the in-focus position back to the reset position (area B). A second timer is started in step S102, and steps S121 and S122 are performed.
Then, the imaging lens 1 is reset within the predetermined time (area B)
It is determined whether or not the output has returned to "H" depending on whether or not the output of the switch S3 has become "H".

If the image pickup lens 1 has not returned to the reset position (area B), the flow advances to step S124 to change to pulse driving and intermittently drive the focusing motor 9. In step S125, it is determined whether the imaging lens 1 has returned to the reset position, and if it has returned to step S12
Then, the process proceeds to 3 to stop energizing the focusing motor 9. Then, in step S126, the film is wound up one frame, the first and second timers are reset, and the program ends.

According to the above operation, if the photographer mistakenly stops the movement of the imaging lens 1 during focusing or focusing return, the focusing motor 9 is switched to the intermittent drive. Therefore, the imaging lens 1 can be moved without the fear that the lock motor flows and the focusing motor 9 generates heat, and the focusing movement and the return movement can be performed.

In this embodiment, when the focusing motor 9 is started to be driven, the focusing motor 9 is energized by directly applying a power supply voltage or by intermittent driving so that the speed is constant regardless of fluctuations in the power supply voltage. It is also envisaged that it will be performed. However, it is preferable to set the intermittent drive during an abnormality in the present invention so as to have a slower speed than the intermittent drive that has the constant speed described above.

Further, in this embodiment, the switch S3, the photo interrupter 7 and the rotary plate 8 are used to detect the position of the lens frame 5, but the combination of the photo interrupter 7 and the rotary plate 8 is used to detect the absolute position of the lens frame 5. If the position can be detected, the switch S3 can be omitted.

Further, in this embodiment, the case where the image pickup lens is moved for focusing has been described as an example.
The present invention can be applied to the case where the imaging lens is moved for zooming.

[0026]

As described above, according to the autofocus camera of the present invention, even when the photographer carelessly touches the lens barrel, even if the lens barrel does not reach the predetermined position within the predetermined time,
By releasing the touched hand, the driving can be continued and the operability can be improved, and the abnormal heat generation of the motor can be prevented.

[Brief description of drawings]

FIG. 1 is a block connection diagram showing an embodiment of an autofocus camera according to the present invention.

FIG. 2 is a flowchart showing an embodiment of an autofocus camera according to the present invention.

[Explanation of symbols]

 1 Imaging Lens 2 Shutter / Shutter 5 Lens Frame 6 Sliding Brush 6a Conductor Pattern 6b Conductor Pattern 7 Photointerrupter 8 Rotating Plate 9 Focusing Motor 10 Focusing Motor Driver 11 Exposure Control Means 12 Photometric Means 13 Distance Measuring Means 14 CPU Circuit 15 Film Supply Sending means 16 Photographic film 17 Lens position commanding means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03B 13/36 8411-2K G03B 3/00 A

Claims (1)

[Claims] 1. An image pickup lens, an image pickup lens drive means for moving the image pickup lens to a predetermined position in the optical axis direction, a photographing lens position detection means for detecting a position of the photographing lens in the optical axis direction, and the image pickup lens. The image pickup lens comprises: a start operation switch for instructing a drive unit to move the image pickup lens; and a control unit for controlling the image pickup lens drive unit based on the detection output of the image pickup lens position detection unit and the state of the start operation switch. However, when the predetermined position is not reached within a predetermined time after the activation operation switch is operated, the control means switches the imaging lens driving means to intermittent driving and moves the taking lens. An autofocus camera.