JP2010139664A - Light quantity adjusting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent operation failure caused by twist of a light shield member, while suppressing bound caused when the light shield member stops. <P>SOLUTION: A light quantity adjusting device includes: a base plate 1 having an aperture 9 through which light is passed; a blade 3 for adjusting a light quantity passing through the aperture 9; and a driving part 6 that parallelly reciprocates the blade 3 with respect to the base plate 1. The blade 3 has a long hole 3 extending in a direction different from the direction of parallel reciprocating movement, and a contact portion 3f disposed in contact with the base plate 1 on an inclined surface at an angle with respect to the direction of the parallel reciprocating movement. The driving part 6 includes a drive motor 6a, an arm member 6b connected to the output shaft of the drive motor 6a, and an engaging pin 6c projecting from the arm member 6b and engaged with the long hole 3. When the blade-side contact portion 3f is brought into contact with the base plate 1, the engaging pin 6c is engaged with the contact-face side end 3e of the long hole 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light amount adjustment mechanism used in an optical apparatus.

In a light amount adjusting mechanism used in an optical apparatus such as a digital still camera or a video camera, it is required to suppress a bounce when the light shielding member is stopped while operating the light shielding member functioning as a shutter at a high speed. For this reason, for example, in Patent Document 1, when the light shielding member is stopped, the light shielding member is brought into contact with the slope portion of the ground plane, so that the load received by the light shielding member from the ground plane is orthogonal to the moving direction of the light shielding member. The technique which suppresses the bounce of the light-shielding member by disassembling in the direction is disclosed.
JP 2007-219198 A

  However, in the technique disclosed in Patent Document 1, since the light shielding member is brought into contact with the slope portion, the light shielding member is displaced along the slope portion from the moving direction, and the light shielding member is twisted when the rigidity of the light shielding member is low. May get caught and cause malfunction.

  Accordingly, an object of the present invention is to prevent malfunction caused by twisting of the light shielding member while suppressing a bounce generated when the light shielding member is stopped.

  In order to solve the above problems, a light amount adjusting device according to the present invention includes a ground plate having an opening that allows light to pass through, a light shielding member that adjusts the amount of light that passes through the opening, and the light shielding member with respect to the ground plate. A parallel-reciprocating drive unit, and the light-shielding member has a long hole extending in a direction different from the direction of the parallel reciprocating motion, and the ground plane is inclined at an angle with respect to the direction of the parallel reciprocating motion. An abutting portion that abuts on the driving motor, and the driving portion projects from the driving motor, an arm member coupled to the output shaft of the driving motor, and protrudes from the arm member to engage with the elongated hole. An engaging pin, and the engaging pin engages with the end of the elongated hole on the abutting portion side when the abutting portion abuts on the base plate.

  ADVANTAGE OF THE INVENTION According to this invention, the malfunctioning by the twist of a light shielding member can be prevented, suppressing the bounce which arises when the light shielding member stops.

  Embodiments of the present invention will be described below in detail with reference to the drawings. The embodiment described below is an example as means for realizing the present invention, and the present invention can be applied to a modified or modified embodiment described below without departing from the spirit of the present invention.

<First Embodiment>
FIG. 1 is an exploded perspective view of a light amount adjusting device A according to an embodiment of the present invention. FIG. 2 is a plan view showing the light amount adjusting device A when the opening 9 is closed. FIG. 3 is an enlarged plan view of the ground plane side contact portion 1c of FIG. FIG. 4 is an enlarged plan view of the stopper portion 1e of FIG. FIG. 5 is a plan view showing the light amount adjusting device A when the opening 9 is open. FIG. 6 is a diagram showing the relationship between the energized states in the A phase and B phase of the drive motor 6a, the rotation angle of the arm member 6b, and the operating time of the blades 3 and 4. As shown in FIG.

[Configuration of the light intensity adjusting device A]
The light amount adjusting device A includes a ground plate 1 having an opening 9 that allows light to pass through, two blades 3 and 4 (light shielding members) that adjust the amount of light passing through the opening 9, and blades 3 and 4 with respect to the ground plate 1. And a drive unit 6 for reciprocally moving them in parallel.

  The base plate 1 rotates the guide pins 1a and 1b provided on its upper surface, the base plate side contact portion 1c with which the blade 3 contacts, the base plate side contact portion 1d with which the blade 4 contacts, and the arm member 6b. And a stopper portion 1e to be regulated.

  The guide pin 1a engages with the blade guide grooves 3a and 4a to guide the blade 3 in the parallel reciprocating motion direction (blade moving direction 11). Similarly, the guide pin 1 b engages with the blade guide grooves 3 b and 4 b to guide the blade 4 in the blade movement direction 11.

  As shown in FIG. 3, the base plate side contact portion 1 c regulates the movement of the blade 3 in the blade movement direction 11, and the blade side contact portion 3 f has an angle with respect to the blade movement direction 11 on the inclined surface. It is formed on the ground plane 1 so as to contact. As shown in FIG. 5, the base plate side contact portion 1 d regulates the movement of the blade 4 in the blade movement direction 11, and the blade side contact portion 4 f has an angle with respect to the blade movement direction 11 on the inclined surface. It is formed on the ground plane 1 so as to contact. As shown in FIG. 4, the stopper portion 1 e is a step formed on the base plate 1 so as to restrict the rotation of the arm member 6 b.

  The blade 3 has a long hole 3c extending in a direction different from the direction of the parallel reciprocating motion (blade moving direction 11), and the base plate 1 is inclined at an angle with respect to the blade moving direction 11 when the opening 9 is closed. The blade side contact portion 3f that comes into contact with the blade guide groove 3a, 3b extends in the blade movement direction 11 and engages the guide pins 1a, 1b to be slidable. Accordingly, the blade 3 is configured to be capable of parallel reciprocation along the blade movement direction 11.

  The long hole 3c has a straight portion extending in a direction substantially perpendicular to the blade moving direction 11, and a bent portion 3d formed continuously from the straight portion and bent toward the blade-side contact portion 3f. That is, the bent portion 3 d extends in a direction different from the direction in which the linear portion extends and the blade moving direction 11. In the present embodiment, the bent portion 3d has a vertical portion 3d 'whose extension line intersects the blade side contact portion 3f or the extension line of the blade side contact portion 3f substantially perpendicularly.

  The contact surface side end portion 3e is a long hole end portion that presses the base plate 1 against the base plate side contact portion 1c by the engagement pin 6c. The blade-side contact portion 3f is a portion where the blade 3 contacts the base plate-side contact portion 1c, and is provided on an extension line of the blade guide grooves 3a and 3b.

  The blade 4 includes a long hole 4c extending in a direction different from the direction of the parallel reciprocation (blade movement direction 11), a blade guide groove 4a extending in the blade movement direction 11 and slidably engaged with the guide pins 1a and 1b. 4b. Thereby, the blade | wing 4 is comprised so that a parallel reciprocation is possible along the blade | wing movement direction 11. FIG. The long hole 4c has a straight portion extending in a direction substantially orthogonal to the blade moving direction 11 and an end portion 4e on the contact portion side toward the blade-side contact portion 4f of the straight portion. The abutting surface side end 4e is a long hole end that presses the blade 4 against the main plate side abutting portion 1d by the engaging pin 6d. The blade side contact portion 4f is a portion where the blade 4 contacts the base plate side contact portion 1d.

  Therefore, the long holes 3c and 4c are appropriately changed from the rotational driving force of the arm member 6b to the driving force for performing the parallel reciprocating motion by engaging with the engaging pins 6c and 6d.

  The blades 3 and 4 are sandwiched and supported by the base plate 1 and the blade cover 5. That is, the blade cover 5 is attached to the base plate 1 by the blade cover fixing screw 8 and supports the blades 3 and 4 in the optical axis direction 10 incident on the opening 9.

  The drive unit 6 includes a drive motor 6a, an arm member 6b connected to the output shaft of the drive motor 6a, an engagement pin 6c that protrudes from the arm member 6b and engages with the elongated hole 3c, and an arm member 6b. It has an engaging pin 6d that protrudes and engages with the elongated hole 4c.

  In this embodiment, the drive motor 6a is a stepping motor that adjusts the amount of light passing through the opening 9 by stepping the blades 3 and 4. The drive motor 6 a is fixed to the main plate 1 by a motor fixing screw 7. The drive motor 6a is, for example, a two-phase, ten-pole PM stepping motor disclosed in Japanese Patent Application Laid-Open No. 2006-280174. The drive motor 6a drives the blades 3 and 4 by 1-2 phase excitation.

  The arm member 6b is press-fitted or adhesively fixed to the output shaft of the drive motor 6a, and transmits the rotational driving force of the drive motor 6a to the blades 3 and 4. The engaging pin 6 c engages with the long hole 3 c and transmits a rotational driving force to the blade 3. The engaging pin 6d engages with the long hole 4c and transmits the rotational driving force to the blade 4. The engagement pin 6 c is engaged with the contact surface side end portion 3 e when the blade side contact portion 3 f of the blade 3 contacts the ground plate side contact portion 1 c of the base plate 1, and the blade side of the blade 3 When the contact portion 3f comes into contact with the ground plane side contact portion 1c of the base plate 1, it comes into contact with the contact surface side end portion 4e with a delay from the contact timing.

  According to the above-described configuration, as the drive motor 6a is excited and stepped, the blades 3 and 4 move in the blade moving direction 11 via the arm member 6b, and the amount of light passing through the opening 9 is stepwise. Adjustable.

[Detailed Configuration and Operation Procedure of Light Amount Adjustment Device A]
First, the drive motor 6a step-drives the blades 3 and 4, and the blades 3 and 4 hold the opening 9 in a fully opened state as shown in FIG. Next, the drive motor 6a step-drives the blades 3 and 4 to a predetermined step position, and maintains a predetermined opening state (including a fully opened state) that provides a desired amount of light that passes through the opening 9. Thereafter, the drive motor 6a step-drives the blades 3 and 4 to the step position where the blades 3 and 4 are in the fully closed step position, whereby the blades 3 and 4 perform the shutter operation with the opening 9 in the fully closed state as shown in FIG.

  Here, since the drive motor 6a cannot suddenly stop at the position where the opening 9 is fully closed (fully closed step position), hunting (bounding) occurs due to the large inertial force of the blades 3 and 4. However, the blade 3 is stepped by the base plate side contact portion 1c and the blade side contact portion 3f coming into contact with each other at an angle with respect to the blade movement direction 11 of the blade 3 at the fully closed step position. Reduce hunting in That is, since the base plate side contact portion 1c and the blade side contact portion 3f are set to contact with each other at an inclined surface at an angle with respect to the blade moving direction 11, the bounding force is received by these contact surfaces. The amount of bounce in the blade movement direction 11 is reduced.

  Moreover, the component which acts in the direction different from the blade | wing movement direction 11 among the bound forces received by the above-mentioned contact surface generates the twist operation | movement which twists the blade | wing 3. FIG. Thereby, the catching defect of the blade | wing 3 may generate | occur | produce. However, since one end side of the long hole 3c of the blade 3 is bent in the direction of the blade side contact portion 3f that contacts the ground plate side contact portion 1c of the base plate 1, the twisting operation of the blade 3 is performed in the long hole 3c. It slides around the engaging pin 6c in the bending direction. Then, the abutting surface side end portion 3e of the long hole 3c abuts on the engaging pin 6c of the arm member 6b, and the twisting operation is suppressed so as to be sandwiched between the engaging pin 6c and the base plate side abutting portion 1c.

  Further, since the force applied to the engaging pin 6c is different from the blade moving direction 11, it is applied mainly in the radial direction that is not the rotational driving direction of the arm member 6b, and is supported by the arm member 6b and the output shaft of the driving motor 6a. The

  In the normal operation, the contact surface side end 3e of the elongated hole 3c and the engagement pin 6c of the arm member 6b are not in contact with each other.

  Since the vertical portion 3d ′ on the contact surface side, which is the bending direction of the long hole 3c, is substantially perpendicular to the surface of the base plate side contact portion 1c, the twisting operation of the blade 3 is performed in the long hole 3c as described above. It is easy to slide on the vertical part 3d ′ in the extending direction with the engaging pin 6c as an axis. Further, the abutting surface side end portion 3e of the long hole 3c abuts on the engaging pin 6c of the arm member 6b and acts to reliably press the blade 3 against the main plate side abutting portion 1c.

  Further, when excessive stress is applied to the base plate side contact portion 1c, the blade 3 may be deformed. However, the arm member 6b contacts the other stopper portion 1e of the base plate 1 to deform the blade 3. Can be suppressed.

  In addition, the twisting operation of the blade when the blade 3 is in contact with the base plate side contact portion 1c tries to twist the guide pin 1b closest to the engaging pin 6c, but the blade moves from the guide pin 1b. If the main plate side contact portion 1c is on the extension line in the direction, the twisting operation is eased.

  The engagement pin 6c of the arm member 6b contacts the contact surface side end portion 3e of the elongated hole 3c after the timing at which the blade side contact portion 3f contacts the base plate side contact portion 1c. The arm member 6b contacts the base plate side contact portion 1e of the base plate 1 later than the timing at which the engagement pin 6c contacts the blade side contact portion 3e of the bent portion 3d.

  Here, as shown in the drive pattern shown in FIG. 6, the drive motor 6a is stopped by two-phase excitation at the fully closed step position, and the blade 3 is brought into contact with the main plate side contact portion 1c at the stop position. Thereafter, the drive motor 6a moves further from the contact position to the closing side in the direction of pressing the base plate side contact portion 1c from the position where the blade side contact portion 3f contacts the base plate side contact portion 1c. Drive excitation by drive excitation method. That is, the drive motor 6 a is driven by step 1-phase excitation in the closing direction of the opening 9 later than the timing at which the blade side contact portion 3 f contacts the ground plane 1. Thereby, since the engaging pin 6c hold | maintains so that the blade | wing 3 may be pressed against the baseplate side contact part 1c, a bounce is further reduced.

  In addition, this invention is not limited to the above-mentioned embodiment, Various control is possible. For example, in the above-described embodiment, 1-2 phase excitation or two phase excitation drive is used as the drive method of the drive motor 6a. However, a drive method such as microstep drive may be used. In addition, although it is effective to implement these embodiments alone, in recent years, there has been a demand for further increase in shutter speed for the purpose of preventing camera shake and the like. The goal can be reliably achieved.

  As described above, the drive motor 6a drives the blades 3 and 4 by one step, and the blades 3 and 4 hold the opening 9 in the fully opened state as shown in FIG. Here, similarly to the fully closed position, the drive motor 6a cannot be stopped suddenly at the position where the opening 9 is fully opened (full open step position), so hunting (bounding) is caused by the large inertial force of the blades 3 and 4. ) Occurs. However, the blade 4 is stepped by the base plate-side contact portion 1d and the blade-side contact portion 4f coming into contact with each other at an angle with respect to the blade movement direction 11 of the blade 4 at the fully open step position. Reduce hunting. That is, since the base plate side contact portion 1d and the blade side contact portion 4f are set to contact with each other at an angle with respect to the blade movement direction 11, the bounce force is received by these contact surfaces. The amount of bounce in the blade movement direction 11 is reduced.

  Moreover, the component which acts in the direction different from the blade | wing movement direction 11 among the bound forces received by the above-mentioned contact surface generates the twist operation | movement which twists the blade | wing 4. FIG. Thereby, the catching defect of the blade | wing 4 may generate | occur | produce. However, the contact surface side end 4e which is one end side of the long hole 4c of the blade 4 is in the direction of the blade side contact portion 3f which contacts the ground plate side contact portion 1d of the base plate 1, and the blade moving direction 11 The component acting in a direction different from that of the blade 4 tries to move along the elongated hole 4c of the blade 4, but the abutting surface side end 4e of the elongated hole 4c contacts the engaging pin 6d of the arm member 6b, and the engaging pin The twisting operation is suppressed so as to be sandwiched between 6d and the base plate side contact portion 1d.

  Further, since the force applied to the engaging pin 6d is different from the blade moving direction 11, it is applied mainly in the radial direction that is not the rotational driving direction of the arm member 6b and is supported by the arm member 6b and the output shaft of the driving motor 6a. The In the normal operation, the contact surface side end 4e of the elongated hole 4c and the engagement pin 6d of the arm member 6b are not in contact with each other. Further, the abutting surface side end 4e of the long hole 4c abuts on the engaging pin 6d of the arm member 6b and acts to reliably press the blade 4 against the main plate side abutting portion 1d.

  In this embodiment, each blade is brought into contact with each other at each of the fully open position and the fully closed position. However, all the blades are brought into contact with the inclined surface and the engagement pin is engaged with the end on the contact portion side. You may let them. Further, in the fully open position, the drive motor 6a moves further from the contact position to the opening side in a direction in which the blade side contact portion 4f is pressed against the base plate side contact portion 1d than the position where the blade side contact portion 4f contacts the base plate side contact portion 1d. Drive excitation may be performed by a one-step two-phase drive excitation method.

<Other embodiments>
Note that the light amount adjustment device A according to the first embodiment described above can also be applied to an imaging device B as shown in FIG. FIG. 7 is a diagram illustrating an example in which the light amount adjusting device A is applied to the imaging device B.

  The imaging device B includes an imaging element 13 that captures an image and a photographing optical system 12 that forms an image on the imaging element 13. The image pickup device 13 is, for example, a CCD (Charge Coupled Device) that converts light into an electric signal, and the photographing optical system 12 is, for example, an optical lens.

  According to this embodiment, stable shooting with less bounce of the blades 3 and 4 is possible even at a high shutter speed, and particularly when the subject C moves fast (for example, when the subject is playing sports). Is preferred.

It is a disassembled perspective view of the light quantity adjustment apparatus A which concerns on one Embodiment of this invention. It is a top view which shows the light quantity adjustment apparatus A in the closed state of the opening part 9. FIG. FIG. 3 is an enlarged plan view of a ground plane side contact portion 1 c of FIG. 2. FIG. 3 is an enlarged plan view of a stopper portion 1 e in FIG. 2. It is a top view which shows the light quantity adjustment apparatus A in the open state of the opening part 9. FIG. It is a figure which shows the relationship between the energized state in A phase and B phase of the drive motor 6a, and the rotation angle of the arm member 6b, and blade | wing operation time. It is a figure which shows the example which applied the light quantity adjustment apparatus A to the imaging device B. FIG.

Explanation of symbols

A Light quantity adjusting device 1 Ground plate 1f, 1d Ground plate side contact portion 1e Stopper portion 3, 4 Blade 3c, 4c Long hole 3d, 4d Bending portion 3e, 4e Contact surface side end portion 3f, 4f Blade side contact portion 6 Drive Part 9 Opening

Claims (10)

A ground plane having an opening through which light passes;
A light shielding member for adjusting the amount of light passing through the opening;
A drive part for reciprocating the light shielding member in parallel with respect to the base plate,
The light shielding member is
An elongated hole extending in a direction different from the direction of the parallel reciprocation;
An abutting portion that abuts the ground plane at an angle with respect to the direction of the parallel reciprocating motion;
The drive unit is
A drive motor;
An arm member coupled to the output shaft of the drive motor;
An engaging pin that projects from the arm member and engages with the elongated hole;
The engagement pin engages with an end portion of the elongated hole on the contact portion side when the contact portion contacts the base plate.   The light amount adjusting device according to claim 1, wherein the long hole has a bent portion that is formed at an end portion of the long hole on the contact portion side and bends toward the contact portion.   The light amount adjusting device according to claim 2, wherein the bent portion is formed so that an extension line thereof intersects the contact portion or an extension line of the corresponding contact portion substantially perpendicularly.   The said engaging pin contact | abuts the edge part by the side of the said contact part of the said long hole behind the timing which the said contact part contact | abuts to the said baseplate, The any one of Claim 1 thru | or 3 characterized by the above-mentioned. The light quantity adjusting device according to item 1.   5. The arm member according to claim 1, wherein the arm member abuts on the base plate after a timing at which the engagement pin abuts on an end of the elongated hole on the abutting portion side. The light quantity adjusting device according to item.   6. The stepping motor according to claim 1, wherein the driving motor is a stepping motor that is driven and held by one step in a direction in which the contact portion is pressed against the contact portion rather than a position where the contact portion is in contact with the base plate. The light quantity adjusting device according to claim 1.   The light amount adjusting device according to claim 6, wherein the stepping motor is driven by one step and is excited by one-phase excitation.   The light quantity according to claim 6 or 7, wherein the stepping motor is driven and held one step in a direction in which the contact portion is pressed against the abutting portion with a delay from a timing at which the contact portion abuts on the ground plate. Adjusting device. The ground plate has a guide pin protruding from the ground plate,
The light-shielding member has a guide groove extending in the direction of the parallel reciprocating motion and slidably engaging the guide pin;
The light amount adjusting device according to claim 1, wherein the contact portion is provided on an extension line of the guide groove.   An imaging apparatus comprising the light amount adjusting device according to claim 1.

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