JP2004325673A - Sector driving device for camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized, inexpensive sector driving device for camera. <P>SOLUTION: The sector driving device is provided with a base plate 1 with an aperture 1a, a sector 12 for opening/closing the aperture 1a formed in the base plate 1, an electromagnetic actuator 4 for driving the sector 12, a drive transmission means T for transmitting the drive of the electromagnetic actuator 4 to the sector 12, a 1st detecting means for detecting a state where the sector 12 opens the aperture 1a and a 2nd detecting means for detecting a state where the sector 12 closes the aperture 1a, and the 1st detecting means and the 2nd detecting means are constituted of movable switches 17 and 19 and a fixed switch used in common. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sector drive device such as a camera shutter.
[0002]
[Prior art]
A conventional camera sector drive device has a fully closed position of a sector as an initial position, and has a home switch including a spring and a spring receiver for detecting the initial position (Japanese Patent Laid-Open No. 2002-196392). . The spring of this home switch is supported by a shaft fixed to the main plate, one end of which is fixed and the other end is open. The spring receiver is fitted on a shaft fixed to the main plate, and is provided at a position where the open end of the spring can be elastically contacted with a predetermined elastic force. The state where the open end is separated from the spring receiver is the OFF state of the home switch, which is set to the initial position of the sector drive ring.
[0003]
When the shaft and the pinion of the rotor are rotated by the actuator in the initial position where the home switch is in the off state, the pinion of the gear rotates in conjunction with this rotation, thereby rotating the sector drive ring. The rotation of the sector drive ring starts opening the sector. At the same time, the drive pin moves clockwise, releasing the pressing force of the switch drive lever against the arm. Then, the switch drive lever becomes free and releases the pressing force exerted on the open end of the spring, so that the spring resiliently contacts the open end with a predetermined elastic force to the spring receiver by its own elastic force to turn on the home switch. To When the home switch is inverted from the off state to the on state, the opening operation of the sector is detected. When the necessary exposure time has elapsed, the actuator is rotated in the reverse direction, and the sector drive ring is returned to the initial position. Then, the home switch is turned from the on state to the off state, and it is detected that the sector has returned to the initial position.
[0004]
In the focal plane shutter, the above-described switch is provided at the end of operation of each of the sector drive levers of the front curtain and the rear curtain to detect the end of travel of the sector drive lever.
[0005]
[Patent Document 1]
JP-A-2002-196392 [0006]
[Problems to be solved by the invention]
As described above, conventionally, detection of movement of a sector or return to the initial position has been performed using one switch. This is because increasing the number of switches is disadvantageous in terms of space. Further, the focal plane shutter which is a relatively large shutter is provided with two switches as described above to detect the end of the travel of the lever. This is because the focal plane shutter is often large, and it is easy to provide two switches because there is enough space. An object of the present invention is to provide a small-sized and low-cost sector drive device having a small number of components.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a sector drive device for a camera according to the present invention includes a base plate having an aperture, a sector provided on the base plate, the aperture of which can be opened and closed, a drive unit for driving the sector, and a sector provided with an aperture. A first detecting means for detecting a state in which the sector is open, and a second detecting means for detecting a state in which the sector closes the aperture, wherein the first detecting means and the second detecting means Are provided with movable switches, respectively, and between the movable switch of the first detecting means and the movable switch of the second detecting means, there are provided a fixed switch with which the movable switches abut and a switch actuation which operates in conjunction with the sector. And a switch actuating member, wherein the movable switch of the first detecting means or the movable switch of the second detecting means is provided when the sector has the aperture opened. It is moved away one from the fixed switch, in the state in which the sector is closed the aperture and so as to separate the other movable switch from the fixed switch.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. Here, a sector driving device for driving a sector of a light shielding device of a digital camera will be mainly described. FIGS. 1 and 2 show a main part of a light shielding device of a digital camera according to an embodiment of the present invention. In these drawings, in order to clearly show the internal configuration, a printed board P described later and a top plate portion of the support board 3 described later are omitted, and only the outline of the board is shown. As shown in FIGS. 1 and 2, this light-shielding device is similar to a focal-plane shutter in that an image frame (aperture) can be opened and closed by a group of light-shielding blades (sectors) that are superimposed and developed. It has become something. However, it does not have a front curtain and a rear curtain like a focal plane shutter, but is a simple one having only one light shielding curtain corresponding to one of the front and rear curtains. In this embodiment, a sector unit U in which sector arms 13 and 14 and a sector 12 serving as a light shielding curtain are attached to a base plate 1 and a sector drive unit D that opens and closes the sector unit U are mounted on the base plate 1 of the sector unit U. Easy to put on and take off.
[0009]
The base plate 1 of the sector unit U is formed of a substantially rectangular plate-like body, and an aperture 1a is provided near the center thereof. On the lower surface of the main plate 1, there are provided sectors 12 and sector arms 13, 14, which will be described later. A sector drive unit D that drives the sector 12 via the sector arm 13 is mounted on the upper surface of the main plate 1. The sector drive unit D is positioned by a positioning pin (not shown) projecting from the upper surface of the main plate 1 and fixed to the main plate 1 by screws 10 as fixing means (see FIG. 3).
[0010]
The sector drive unit D includes an electromagnetic actuator (hereinafter, referred to as “actuator”) 4 which is a driving unit previously mounted on the support substrate 3 via an intermediate member 6 which will be described later, a synchro switch 5 which is a sector position detecting unit which will be described later, and A drive transmitting means T is provided on the lower surface side of the intermediate member 6 (see FIG. 4). A printed circuit board P for supplying electric power to the actuator 4 and the synchro switch 5 is provided above the sector drive unit D in the drawing.
[0011]
FIG. 4 is an enlarged sectional view showing a main part of each mechanism of the sector drive unit D and the sector unit U. Of the drive mechanism of the sector drive unit D, the drive section including the actuator 4 and the synchro switch 5 is fixed to one surface (lower surface) of the support substrate 3 via an intermediate member 6 which is undetachably mounted. . On the other surface (upper surface) of the support substrate 3, a printed circuit board P is fixed. The support substrate 3 has a base plate portion 3a formed of a rectangular plate-like body (see FIG. 1), and a hook portion 3b for holding the intermediate member 6 is provided at both ends. The intermediate member 6 is capable of holding the actuator 4 and the synchro switch 5 and has a mounting portion 6f for attaching to the main plate 1. Since the unitized sector drive unit D is an independent unit that can be easily attached to and detached from the sector unit U, it can be attached to various sector units.
[0012]
The above-described actuator 4 is a kind of a known pulse motor, and includes a stator 4a, a driving coil 4b, and a rotor 4c made of a permanent magnet. The actuator 4 has a static stable position in which the rotor 4c is kept de-energized by the position of the magnetic pole of the rotor 4c and the position of the magnetic pole provided on the stator 4a. For this reason, the magnetic poles of the rotor 4c move between the magnetic poles of the stator 4a by being energized, and are stopped at a static stable position to hold the rotor 4c. The static stable position is determined by the number of magnetic poles of the rotor 4c and the number of magnetic poles provided on the inner peripheral portion of the concave portion of the stator 4a surrounding the rotor. In this case, the rotor 4c has two magnetic poles and the stator 4a has By using a combination of four magnetic poles, two stable stable positions are provided. The actuator 4 is fixed in a state where the actuator 4 is pressed against the base plate 3 a of the support substrate 3 by the intermediate member 6. A rotating shaft 4d integral with the rotor 4c is provided so as to penetrate the intermediate member 6 and protrude downward.
[0013]
A drive lever 8 constituting drive transmission means T is fixed to a tip (lower end in FIG. 4) of a rotary shaft 4d integral with the rotor 4c of the actuator 4. A sector drive lever 9 which constitutes a drive transmission means T which can be linked with the drive lever 8 is swingably supported on a support shaft 6 b protruding from the lower surface of the intermediate member 6. The sector drive lever 9 can be interlocked with the drive lever 8 by engaging the teeth 9a with the teeth 8a of the drive lever 8. As shown in FIGS. 3 and 4, the drive lever 8 is formed of a fan-shaped plate having a small opening degree, and a portion corresponding to the pivot of the fan is fixed to the rotation shaft 4d of the actuator 4 so as to be integrally rotatable. I have. An arc portion formed at the tip of the drive lever 8 is a tooth portion 8a formed by engraving the gear tooth profile. The sector drive lever 9 is formed in an arc shape within a range of a predetermined distance from the center of rotation, and a tooth portion 9a which can mesh with the tooth portion 8a of the drive lever is provided in a part around the arcuate portion. is there. An arm 9b extending outward is formed on a part of the arc portion where the tooth portion 9a is not provided. On the upper surface of the arc portion (see FIG. 4), a contact pin 9c, which will be described later, protrudes upward at the tip of the short arm 9e. A drive pin 9d that engages with the sector arm 13 for driving the sector unit U is provided on the lower surface of the distal end of the arm 9b.
[0014]
In this way, the drive transmission means T is such that the drive lever 8 swings by the rotation of the actuator 4, and the sector drive lever 9 is interlocked with the drive lever 8 via the gear transmission mechanism. Angle. The swing angle of the sector drive lever 9 is the same as the swing angle of the sector arm 13. As a result, the reciprocating amount of the sector 12 is determined by the swing angle of the sector drive lever 9 and the length of the sector arm 13. Has become. When the swing angle of the sector drive lever 9 is changed, the gear ratio may be changed or a contact member may be provided to limit the swing angle.
[0015]
Next, the above-mentioned synchro switch 5 will be described. The synchro switch 5 used in this sector drive device detects a drive state of the sector drive lever 9 by two detection means and detects that the sector 12 is fully open or fully closed at the time of exposure. This is a detection sensor. Then, as shown in FIG. 3, a detection pin 18 which is a fixed switch and detection springs 17, 19 which are movable switches and biasing members provided at symmetrical positions with the detection pin 18 interposed therebetween, the detection springs 17, 19 and 19 And a contact / separation pin 9c, which is a switch actuating member that can swing between them. The detection spring 17, which is the first detection means, employs a torsion coil spring having a straight portion extending at both ends in opposite directions. The coil portion located at the center of the spring is inserted into a shaft portion 6g protruding from the intermediate member 6, and one of the linear portions abuts on the contact / separation pin 9c of the sector drive lever 9 when the sector 12 is overlapped. It is possible. The other straight portion is in contact with a protrusion 6 c protruding from the upper surface of the intermediate member 6. The other straight portion is bent at a right angle at the front end and extends upward. The front end is electrically connected to the printed circuit board P to serve as the information output section 17a, and thereby the CPU as the control means of the camera main body is provided. The detected data can be output (see FIG. 4).
[0016]
The detection spring 19, which is the second detection means, has the same configuration as the detection spring 17, and employs a torsion coil spring having straight portions extending at both ends in opposite directions. The coil portion located at the center of the spring is inserted into a shaft portion 6h protruding from the intermediate member 6, and one linear portion is connected to the contact / separation pin 9c of the sector drive lever 9 when the sector 12 is unfolded. 18 can be contacted. The other straight portion is in contact with a protrusion 6 i projecting from the upper surface of the intermediate member 6. The other straight part is bent at a right angle at the end like the detection spring 17 and extends upward, and the end is electrically connected to the printed circuit board P to be used as an information output part, so that the camera body can be used. The detected data can be output to the CPU.
[0017]
The detection pin 18 is made of a conductive rod material, and both ends of the detection pin 18 are supported between the printed board P and the intermediate member 6, and the terminal 18a at one end thereof is electrically connected to the printed board P. I have. When the sector 12 is expanded and the aperture 1a is in the fully closed state, the detection pin 18 can abut on the intermediate position of the linear portion of the detection spring 17, and when the sector 12 is superimposed and fully opened. The detection spring 19 is provided at a position where an intermediate position of the linear portion can be brought into contact. That is, the detection spring 17 and the detection spring 19 share the detection pin 18. Detection data for detecting the contact / separation state between the detection spring 17 and the detection spring 19 and the detection pin 18 can be output from terminal portions 17a and 18a provided on the printed circuit board P. The contact / separation operation is performed by the detection spring 17 or the detection spring 19 following the swing of the contact / separation pin 9c integral with the sector drive lever 9.
[0018]
The detection springs 17, 19, which are the first and second detection means, employ torsion coil springs having linear portions extending in opposite directions at both ends, and each detection spring is sandwiched by a common detection pin 18. 17 and 19, and the contact / separation pin 9c, which is a switch actuating member, is provided between the detection spring 17 having the detection pin 18 and the detection spring 19 so as to be swingable. The detecting means can be provided in the sector driving device. For this reason, it is possible for the conventional detecting means to detect two states of the start and end of the operation of one member without increasing the size of one.
[0019]
As shown in FIG. 4, the integral connection between the base plate 1 of the sector unit U and the drive unit D is performed by positioning pins (not shown) provided at a plurality of locations on the upper surface of the base plate 1 and mounting portions 6 f of the intermediate member 6. This is performed by aligning the positioning holes 6a provided, pressing the two in a direction approaching each other, and further tightening them with screws 10 as fixing means. FIG. 4 shows a state in which the sector drive unit D is mounted on the main plate 1. By this mounting, the sector drive lever 9 swingably supported by the shaft portion 6b protruding from the intermediate member 6 is stably supported by the protrusion 1g protruding from the main plate 1, The drive pin 9b penetrates the arc groove 1c of the main plate and protrudes to the rear side.
[0020]
A sector 12 for opening and closing the aperture 1a and sector arms 13 and 14 are attached to the other surface (back surface) of the main plate 1. The main unit 1, the sector 12, and the sector arms 13 and 14 constitute a sector unit U. As shown in FIGS. 1 and 2, the sector drive mechanism is a parallel link mechanism including a plurality of sectors 12 (only one is shown) and a pair of sector arms 13 and 14 for reciprocating the sectors. . Among the sector arms constituting the parallel link mechanism, a sector arm 13 located below is swingably supported by a shaft 1d (see FIG. 3) concentric with the rotation center of the sector drive lever 9. A drive pin 9d of the sector drive lever 9 is fitted into a hole provided at an intermediate position of the sector arm 13, so that the arm can be driven by the sector drive lever 9. The distal end of the first sector arm 13 is connected to the sector 12 via a connection pin 13a. On the other hand, the sector arm 14 located above the sector arm 13 is swingably supported on the upper surface of the base plate 1 at a position slightly away from the support point of the sector arm 13. The distal ends of the sector arms 13 and 14 are swingably connected to the sector 12, so that a parallel link mechanism is established and the sector 12 can be moved in parallel. Note that the sector 12 is protected by a blade holding plate 15.
[0021]
Next, the operation of this embodiment will be described with reference to the sequence chart shown in FIG. The open / close lever in FIG. 5 indicates the sector drive lever 9, the close switch indicates the detection spring 19, and the open switch indicates the detection spring 17. First, in the initial state, the power supply to the drive coil 4b of the actuator 4 is turned off, so that both the sector drive lever 9 and the sector 12 are stationary at the initial position (statically stable position). At this time, in the sync switch 5, the detection spring 17 and the detection pin 18 are in contact (short) with each other (see FIGS. 1 and 3). The detection spring 19 and the detection pin 18 are separated (open). Next, when a release switch (not shown) of the camera body is turned on, a negative current flows from the CPU to the drive coil 4b of the actuator 4, the rotor 4c rotates forward, and the sector 12 is moved via the drive transmission means T. Start opening the aperture 1a. At this time, the sector 12 is easier to start because the urging force of the detection spring 19 can be used for the driving force. For this reason, power consumption at the time of driving is small, and acceleration is also easy to occur, so that power saving and speeding up of sector driving are facilitated. By the drive of the drive transmission means T, the contact / separation pin 9c rotates clockwise, and the detection spring 19 and the detection pin 18 contact (short). Signal data generated by this state change is output to the CPU.
[0022]
When the contact / separation pin 9c further rotates, the contact / separation pin 9c pushes the detection spring 17 to separate (open) the detection spring 17 and the detection pin 18 (see FIG. 2). Signal data generated by this state change is output. At this time, the sector 12 is braked by the urging force of the detection spring 17, so that the impact and collision sound at the end of traveling of the sector 12 are reduced. The CPU confirms the end of the opening operation of the sector 12 based on signals from the two detection means of the detection spring 17 and the detection spring 19. Then, the power supply to the drive coil 4b is turned off. This position is another static stable position of the rotor 4c, and can be stopped at this position even in a non-energized state. Further, since the urging force of the detection spring 17 is transmitted to the drive transmission means T via the contact / separation pins 9c, the drive transmission means T and the sector arm are in a loose state. During this power-off period, the image sensor is driven by the CPU, and exposure (image capture in FIG. 5) by the image sensor is performed. In FIG. 5, a plurality of arrows are drawn when the state of each switch is changed, which indicates that the switch is switched at a certain timing because the switch switching position is not constant due to a problem of component accuracy or the like.
[0023]
The above-described exposure is started when the CPU receiving the output of the signal data change of the detection spring 17 and the detection spring 19 confirms that the aperture 1a is open, and issues an exposure start signal to the image sensor. During the exposure operation, the power supply to the drive coil 4b of the actuator 4 is turned off, so that noise can be prevented from being generated during the exposure and power consumption can be reduced. Since the rotor 4c is kept in the statically stable position and de-energized even when the power to the drive coil 4b is turned off, the sector 12 does not move on its own.
[0024]
When the exposure operation that has already been started is completed, the CPU drives the drive coil 4b of the actuator in accordance with the positive current to rotate the sector drive lever 4 in the direction in which the sector 12 is developed, thereby rotating the sector drive lever 9 and simultaneously rotating the sector 12 Starts closing the aperture 1a. By the drive of the drive transmission means T, the contact / separation pin 9c rotates counterclockwise, and the detection spring 17 and the detection pin 18 contact (short). Signal data generated by this state change is output to the CPU.
[0025]
When the contact / separation pin 9c further rotates, the contact / separation pin 9c pushes the detection spring 19 to separate (open) the detection spring 19 and the detection pin 18. At this time, the sector 12 is braked by the urging force of the detection spring 19, so that the impact and the collision sound at the end of traveling of the sector 12 are reduced. The CPU receiving the signal change output of the detection spring 17 and the detection spring 19 confirms that the aperture 1a is closed. Thus, the sector 12 returns to the initial position, that is, the aperture 1a is closed, and the CPU turns off the power supply to the drive coil 4b of the actuator. Since the initial position is a static stable position, it can be stopped at the initial position even in a non-energized state. At the same time as the energization of the drive coil 4b is stopped, the image data accumulated in the image sensor by exposure (image capture in FIG. 5) is output to the CPU (data read in FIG. 5), thereby completing one operation of photographing. The data read from the imaging device is stored by being output to the storage device of the camera body.
[0026]
In the above description, this sector drive device can be applied to a focal plane shutter, a lens shutter, an aperture device, and the like in addition to the above-described light shielding device. Further, the number of magnetizations of the rotor of the electromagnetic actuator is not limited to two, and may be more. In this case, two or more static stable positions are formed, but two adjacent static stable positions may correspond to the fully open position and the fully closed position of the aperture. Also, the description has been given on the assumption that the current is supplied to the drive coil by the constant voltage circuit. However, it is of course possible to employ a constant current circuit. Although a gear mechanism is employed as the transmission mechanism of the drive transmission means, a link mechanism, a slider / crank mechanism, or the like may be employed. Further, in the present embodiment, the state where the sector has opened the aperture is detected by the first detection means being opened and the second detection means is being short-circuited, and the state where the sector is closing the aperture is detected by the first detection means. Although the detection is performed in a state where the first detection unit is short-circuited and the second detection unit is opened, the detection may be reversed. That is, when the first detecting means is open and the second detecting means is short-circuited, the closing is detected, and when the first detecting means is short-circuited and the second detecting means is opened, the opening is detected. You may. The driving means is not limited to the electromagnetic actuator, but may be driven by a biasing member such as a spring.
[0027]
【The invention's effect】
The sector drive device according to the present invention has a configuration in which the fixed switch and the switch operating member are arranged between the movable switch of the first detecting means and the movable switch of the second detecting means, and the fixed switch is shared. Therefore, the number of parts can be reduced, and the size and cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a plan view showing a state where an aperture is fully closed.
FIG. 2 is a plan view showing a state where an aperture is fully opened.
FIG. 3 is an enlarged view of a main part.
FIG. 4 is an enlarged sectional view of a main part.
FIG. 5 is a sequence chart showing an operation of one embodiment.
[Explanation of symbols]
U Sector unit D Sector drive unit T Drive transmission means 1 Ground plate 1a Aperture 3 Support substrate 4 Driving means (actuator)
5 Sector position detection means (sync switch)
6 Fixing member 8 Drive lever 9 Sector drive lever 9c Contact / separation pin 12 Sector 13, 14 Sector arm 15 Blade holding plate 17, 19 Detection spring 18 Detection pin

Claims (1)

A base plate having an aperture;
A sector provided on the base plate and capable of opening and closing the aperture;
Driving means for driving the sector;
First detection means for detecting a state in which the sector has opened the aperture;
Second detection means for detecting a state in which the sector has closed the aperture,
Has,
The first detection means and the second detection means each include a movable switch, and a movable switch is provided between the movable switch of the first detection means and the movable switch of the second detection means. A fixed switch contacted by a switch and a switch operating member that operates in conjunction with the sector are arranged,
The switch operating member, when the sector has opened the aperture, causes one of the movable switch of the first detecting means or the movable switch of the second detecting means to be separated from the fixed switch, and Wherein the other movable switch is separated from the fixed switch when the aperture is closed.

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