JP2739052B2 - Camera auto focus device - Google Patents

Description

The present invention relates to an automatic focusing device for a camera, and more particularly, to an automatic focusing device for a camera.
The present invention relates to an automatic focus adjustment device for a camera that can confirm an operation of a distance member from a start position to a transition of a taking lens to a focusing position.

[Prior Art] As shown in FIG. 6, in a conventional automatic focusing apparatus for a camera, a photographic lens focusing mechanism is provided on a shutter unit side. The drive member 1 rotatably attached to the substrate on the shut unit side is driven by a step motor 4 via an idler 3 meshing with a sector gear 1a on the periphery, and the step motor 4 is combined according to a preset program. It is configured to rotate in forward and reverse directions in response to performing forward and reverse rotations for focus, exposure, and return. A sector opening / closing cam 1b for opening / closing a sector (not shown) is formed so as to protrude.

On the other hand, reference numeral 6 denotes a distance member for operating a photographic lens (not shown) via a lens driving section 6a and moving and setting the photographic lens to a focus position. Mounted to get. The distance member 6 is provided with a sector gear 6b that meshes with a pinion 7a integral with the ratchet wheel 7, and is provided with a clockwise rotation behavior in the figure by a spring 6c so as to rotate together with the drive member 1. Have been. Reference numeral 8 denotes a locking lever pivotally supported by a pin on the substrate 2 in a state where dextrorotation is given by a spring 8a, and is configured to be attracted and held by the electromagnet 9 via an iron piece 9a connected to one end thereof. When the electromagnet 9 (also called the AF magnet) is demagnetized, it rotates clockwise in the figure,
The claw at the tip is engaged between the teeth of the ratchet wheel 7 to lock the distance member 6 at the in-focus position.

On the other hand, the pinion 11a fixed to one end of the step motor 4 for driving the driving member 1 rotates the ratchet wheel 7 clockwise via the driving member 1 and the distance member 6 by the reverse rotation of the step motor 4 to push up the locking lever 8. . And
When the electromagnet 9 is energized at that time, the locking lever 8 is held at a position where the tip end does not lock the teeth of the ratchet wheel 7.

Next, the step motor 4 shifts to forward rotation for focusing operation, and transmits this rotation to the driving member 1 disposed on the substrate 2 via a pinion 11a fixed to the rotation transmission shaft, and the spring 6c
By rotating the distance member 6 following this in the clockwise direction in the figure, the scanning lever (not shown) scans the held light emitting element by rotating the distance member 6, and the light receiving element (not shown) The light from the light emitting element is received as reflected light from the subject, and a focus signal is output at the focal point to display distance information in the finder. Further, the power supply to the electromagnet 9 is cut off by the focus signal, the locking lever 8 is turned clockwise, the ratchet wheel 7 is locked, the distance member 6 is locked, and the taking lens is positioned at the focus position.

When the step motor 4 further rotates, the driving member 1 rotates clockwise, and the pin 5a of the sector opening / closing lever 5 is turned leftward by the cam portion 1b. When the pin 5a turns to the left, the stepping motor 4 which controls the rotation of the distance member 6 is disconnected by locking the ratchet wheel 7 by the locking lever 8 to perform a predetermined shutter opening / closing operation. The forward and reverse rotations of the step motor 4 are performed by phase pulses generated by the step motor drive circuit 4a.

When the distance member 6 is in the starting position, the distance member 6 is constantly urged clockwise by the elasticity of the spring 6c, and the home switch HS provided as distance member position confirmation means is provided.
Is open. When the distance member 6 transitions from the starting position to the focusing operation, the home switch HS is closed, so that the distance member 6
It turns out that the operation of is normal.

[Problems to be Solved by the Invention] In the automatic focusing device for a camera having the above configuration, since the home switch HS is used for the pin 6d of the distance member 6, the step motor 4 is reversed, and the ratchet wheel 7 is moved clockwise. And the locking lever 8 is pushed up so that the tip of the locking lever 8 is held at a position where the tooth portion of the ratchet wheel 7 is not locked. From the first tooth portion of the ratchet wheel 7, a minimum stroke in which the tooth portion cannot be provided is required until the distance member 6 rotates forward through the pinion 7a and the home switch HS is closed. Normally, the tooth portion is provided with 30 to 40 steps, but the minimum stroke of the ratchet wheel 7 without the tooth portion is required to be 8 pulses in terms of the number of pulses, and is about 20% of 30 to 40 of the tooth portion. , And this stroke cannot be used for the focusing operation.

In addition, since the engagement between the tooth portion and the leading end of the locking lever 8 is precisely processed so as to be extremely small, the first tooth portion and the locking lever 8 are not properly engaged with each other while the following engagement is performed. There is a problem that the operation by the distance member is performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described difficulties, and has a means for confirming a position at an operation monitoring point provided during the operation of a driving member, and a distance in response to an output signal of the position confirmation means. An object of the present invention is to provide an automatic focusing device for a camera in which a means for controlling execution of a focusing operation of a member is provided, thereby reducing an invalid stroke of a distance member that can be used at a lens focusing position. .

It is another object of the present invention to provide an automatic focusing device for a camera that can expect a normal focusing operation by providing a means for preventing an abnormal restraint at an initial position of a distance member.

[Means for Solving the Problems] An automatic focusing apparatus for a camera according to the present invention includes a motor capable of rotating forward and reverse, a driving member operated by the motor to perform a shutter exposure operation, and a driving member following the driving member. A distance member that operates to set the taking lens to the initial position, and extends the distance member, a distance member locking mechanism that locks the distance member at a predetermined extension position including the initial position, and during the operation of the driving member. A driving member position confirmation unit that confirms the position of the driving member at the provided operation monitoring point and outputs a position confirmation signal; and the predetermined distance from the starting position of the distance member at the initial position in response to the position confirmation signal. And control means for controlling the execution of the operation until being locked at the feeding position.

In addition, the automatic focusing apparatus for a camera according to the present invention includes a motor capable of rotating forward and backward, a driving member operated by the motor to perform a shutter exposure operation, and a photographing lens operated following the driving member to move the photographing lens to an initial position. And a distance member to be extended, a distance member locking mechanism for locking the distance member to a predetermined extended position including the initial position, and the operation monitoring point provided during the operation of the driving member. A driving member position confirmation means for confirming the position of the driving member and outputting a position confirmation signal, and being locked at the predetermined extended position from the starting position of the distance member at the initial position in response to the position confirmation signal. And a distance member abnormal lock prevention means for preventing abnormal lock at the initial position of the distance member.

[Embodiment] Hereinafter, an embodiment of an automatic focusing apparatus for a camera according to the present invention will be described in detail with reference to FIGS.

1 to 4 and FIG. 5, the same components are denoted by the same reference numerals and description thereof will be omitted.

A pin 1c is provided in a concave portion provided on the outer peripheral portion of the driving member 1 shown in FIG. Pin 1c is supported the front end of the movable contact h ₁ of constructed home switch HS in a normally open contact, the drive member 1
There movable contact h ₁ and the fixed contact h2 rotates clockwise to close.

The opening and closing of the home switch HS is controlled by the control circuit CPU shown in Fig. 2.
Is input to the main control unit 19 via the data bus 20 of FIG.

The opening and closing of the home switch HS is determined by the operation check points SOB ₁ , SOB ₂ , and SOB ₃ of the operation check program ANL shown in FIG. _{3 in} the determination boxes FH ₁ , FH ₂ , and FH ₃ . Also, the operation check point SOB ₄
Opening and closing of the home switch HS in the photometer shown in FIG.
It is determined by the exposure program EXC ₃ no decision box FH _4.
Incidentally, to determine an operation check point SOB ₁ In process execution program EXC ₂ shown in FIG. 3 in box FH _'1.

The forward / reverse rotation pulse transmitting section 15, the AF magnet driving section 16, the shutter speed calculating section 17, the focus adjustment calculating section shown in FIG.
18 photometer 17a, photometric data from ranging unit 18b, the inputted distance measurement data, under the control of the various programs EXC ₁ ~EXC ₅ and ANL.

The distance measuring program EXC ₁ shown in FIG. 3 judges whether the release button SW shown in FIG. 2 is on or off in a decision box F _{1. When} the release button SW is on, the power is held in a process F ₂ , and the process F ₂ is performed. Measure the distance with ₃ . When the distance measurement is executed, the operation check program ANL is started. Operation check program ANL is the operation check point
The opening and closing of the home switch HS in SOB ₁ , SOB ₂ , and SOB ₃ is checked, and if abnormal, the process indicator PI is set to 1, 2, or 3 in processes F ₇ , F ₈ , and F ₁₆ , and the process execution program EXC ₂ Pass control to If it is normal, set the process indicator PI to 8 in process 15, and set the metering and exposure program
Pass control to EXC ₃ .

Operation confirmation program ANL checks the operation check point SOB ₁ in box FH _1, when the normal processing F _4, F _5, reversed F ₆ 3
Executes pulse, AF magnet ON, and 3 forward rotation pulses.

Next, check the operation check point SOB ₂ in box FH _2, when normal, the lens drive stroke sends a forward pulse by the processing F ₁₄ until the end at decision box F _9, the lens drive stroke When finished, proceed as described above
At 15, PI = 8. Forward rotation 5 during the lens drive process
To confirm the operation check point SOB ₃ in th pulse at the decision box FH _3. Except for the fifth pulse of the normal rotation, the decision box F ₁₂ and the process F ₁₃ are executed, and then, one pulse of the normal rotation is transmitted in the process 14.

Process execution program EXC ₂ has PI = 1, PI = 2, PI =
The flow branches at 3 to transit to processing F ₁₇ , F ₂₁ , and F 23. When PI = 1, processing F ₁₇ , F ₁₈ , and decision box F ₁₉ are executed to transmit 4 reverse rotation pulses, add 1 to the counter, and determine whether or not the operation has been repeated n times. In decision box FH ₄ , the operation check point SOB _{1 is determined.} Check. If there is no abnormality as a result of monitoring, PI = 0 in process 20 and
Start the metering and exposure program EXC ₃ . AF magnet OFF in the processing F _21, F ₂₂ when the PI = 2, executes the reverse rotation 4 pulsing. PI = 3 AF magnet in the processing F _23, F ₂₄ when the
OFF, 9 pulses of reverse rotation are executed.

The photometry and exposure program EXC ₃ uses PI =
0, PI = 8 and branch at PI ≠ 0, PI ≠ 8, PI ≠ 0, PI
# 8 becomes an illegal function ILL and sends an alarm according to a flow not shown. Process F when PI = 0
_{At 25} , the power hold is set to L, and all operations are completed.
When PI = 8, the operation is normal, and the processes F ₂₆ , F ₂₇ ,
_{F 28, F 29, F 30} , AF magnet OFF in F 31, photometry, AF magnet ON, the exposure operation, AF magnet OFF, the executing the operation program of the reverse rotation to the initial position.

Operation check point SOB ₄ determines at decision box FH _4, in a normal case initiates the abnormal Kakawatome prevention program EXC _4. Abnormal case processing F _32, to confirm the normality of the decision box F _33, tested with a flow of process F ₃₄ points SOB _4.

Abnormal Kakawatome prevention programs EXC ₄ is reversed 1 subroutine F _35, and sends a forward rotation pulse, it is ensured the engagement of claws of the first teeth and the locking lever 8 of the ratchet wheel 7 as shown in Figure 1 Control.

The film feed program EXC ₅ feeds one frame of the film in the process F ₃₆ , sets PI = 0 in the process 37, and jumps to the process 25.

To confirm the operation check point SOB ₁ as shown in FIG. 5 in box FH ₁ to flow from the distance measuring program EXC ₁ to operation confirmation program ANL camera autofocus system of the above configuration [Operation of the invention. Since operation check point SOB ₁ sends out a reverse 3 pulses at normal if processing F4, the rotation angle of the driving member 1 AF magnet in theta ₂ next process F ₅ from theta ₁ is turned ON. Forward rotation 3 in processing F ₆
When a pulse is transmitted, the operation confirmation point SOB ₂ is again detected at the rotation angle θ ₁ ′.
And the operation confirmation point SOB ₃ is obtained at the eighth pulse from the rotation angle θ. Rotation angle is θ _3. Final operation check point SOB ₄ is 4th
Check the photometry and exposure program EXC _{3 in} the decision box FH ₄ in the figure. Reversed to its initial position flow to the final operation check point SOB ₄ that lens return stroke from the process F _31.
Also, a determination of the end position of the lens drive stroke starting from the initial position of the distance members in box F ₉ and F _12.

Incidentally, the partial rotation angle theta ₄ is at the maximum rotation angle of the point of the sector which is not shown in the exposure operation stroke is opened in the sector cams of the driving member 1 of FIG. 1.

Note that the home switch in the above embodiment is not limited to a mechanical contact, and a semiconductor element such as a fort coupler may be used. Further, the driving member and the distance member may be formed on a straight line. Further, the motor may be a sound wave motor or the like.

[Effects of the Invention] An automatic focusing apparatus for a camera according to the present invention includes a motor capable of rotating forward and backward, a driving member operated by the motor to perform a shutter exposure operation, and a photographing lens operated following the driving member to operate. A distance member for setting and extending the distance member to an initial position, a distance member locking mechanism for locking the distance member at a predetermined extension position including the initial position, and an operation monitor provided during the operation of the driving member. A driving member position confirming means for confirming the position of the driving member at a point and outputting a position confirmation signal; and, in response to the position confirmation signal, engaging the predetermined distance from the starting position of the distance member at the initial position. Since the control means controls the execution of the operation until the operation is stopped, there is an effect that the position of the driving member can be confirmed at the operation check point and abnormal operation can be prevented. Further, it is possible to set the stop position of the distance member from the initial position as the lens drive stop position, thereby reducing an invalid stroke that cannot be used as a focusing operation related to the distance member locking mechanism.

A forward / reversely rotatable motor, a driving member that is operated by the motor to perform a shutter exposure operation, a distance member that operates following the driving member to set the photographing lens to an initial position, and that extends; A distance member locking mechanism for locking the distance member at a predetermined extended position including the initial position, and a position confirmation signal for confirming the position of the drive member at an operation monitoring point provided during the operation of the drive member. Drive member position confirmation means for outputting, and control means for controlling execution of an operation from a start position of the distance member at the initial position to being locked at the predetermined extension position in response to the position confirmation signal. Further, since the distance member is provided with a distance member abnormal restraint preventing means for preventing abnormal restraint at the initial position of the distance member, abnormal restraint of the distance member can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an automatic focusing apparatus for a camera according to the present invention, FIG. 2 is a block diagram relating to FIG. 1, and FIGS. 3 and 4 are flowcharts of programs relating to FIG. FIG. 5 is a time chart showing the operation of the program shown in FIGS. 3 and 4, and FIG. 6 is a block diagram of a conventional automatic focusing apparatus for a camera. 1 ... driving member 2 ... substrate 4 ... step motor 6 ... distance member HS ... home switch (drive member position confirmation means) ANL ... operation confirmation program (control means) EXC ₄ ... abnormal restraint prevention program (means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tadashi Ishikawa 934-13 Shiwatari, Yokkaido, Chiba Pref. Seikosha Chiba Works (56) References JP-A-62-200337 (JP, A) JP-A-62 -156634 (JP, A) JP-A-1-252910 (JP, A)

Claims (2)

(57) [Claims] 1. A motor capable of rotating forward and reverse, a driving member operated by the motor to perform a shutter exposure operation, and a distance which operates following the driving member to set a taking lens to an initial position and extend the photographing lens. A member, a distance member locking mechanism for locking the distance member at a predetermined extended position including the initial position, and a position for confirming the position of the drive member at an operation monitoring point provided during the operation of the drive member. A drive member position confirmation unit that outputs a confirmation signal, and controls execution of an operation from the start position of the distance member at the initial position to the engagement of the distance member at the predetermined extension position in response to the position confirmation signal. An automatic focusing device for a camera, comprising: a control unit. 2. A motor which can be rotated forward and backward, a driving member which is operated by the motor to perform a shutter exposure operation, and a distance which operates following the driving member to set the photographing lens at an initial position and extend the photographing lens. A member, a distance member locking mechanism for locking the distance member at a predetermined extended position including the initial position, and a position for confirming the position of the drive member at an operation monitoring point provided during the operation of the drive member. A drive member position confirmation unit that outputs a confirmation signal, and controls execution of an operation from the start position of the distance member at the initial position to the engagement of the distance member at the predetermined extension position in response to the position confirmation signal. An automatic focus adjusting device for a camera, comprising: a control unit; and a distance member abnormal lock prevention unit that prevents abnormal lock at an initial position of the distance member.