Lens unit and method for setting origin of lens unit

Abstract

To set an origin in a short time.SOLUTION: An origin setting device includes a control unit that sets an origin of a movable part of a linear motor by driving the linear motor by two different driving methods.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This technology Lens Unit and Method for Setting Origin of Lens Unit relates to a technology for setting the origin of a linear motor, and more particularly to a technology for setting the origin of a linear motor.

Background Art

[0002] Conventionally, in a linear motor, an incremental type position detection sensor is provided to detect the position of a movable part. The position detection sensor can detect the relative position of the movable part by adding or subtracting a counter each time it detects magnetic marks or optical marks arranged at equal intervals. However, with an incremental type position detection sensor, the absolute position of the movable part cannot be detected.

[0003] Therefore, in a linear motor, in addition to an incremental type position detection sensor, an origin detection sensor for detecting the origin of the movable part is provided. When the linear motor starts, for example, as described in Patent Document 1, after the movable part is reciprocated a plurality of times so that the signal detected by the origin detection sensor changes, the movable part is finally moved and stopped at the position that becomes the origin, and this position is set as the origin. As a result, in a linear motor, it becomes possible to detect the absolute position of the movable part based on the origin.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the above-described method for setting the origin, after the movable part is reciprocated a plurality of times, it is necessary to stop the movable part at the position that becomes the origin. Therefore, it has been difficult to set the origin in a short time.

[0006] Therefore, the present technology aims to set the origin in a short time.

Means for Solving the Problem

[0007] The present technology Lens Unit includes A linear motor for moving a lens, and after driving the linear motor in a first driving method driven by open-loop control, driving the linear motor in a second driving method driven by closed-loop control a control unit that, when driven, sets the origin of the movable part of the linear motor. The first driving method energizes the coil of the linear motor with a predetermined excitation pattern, the second driving method energizes the coil of the linear motor with an excitation pattern corresponding to the position of the movable part, and the control unit sets, as an initial excitation pattern in the first driving method, an excitation pattern that is less than 180° in electrical angle shifted toward the movable range where the movable part can move from a regulating member that restricts the movement of the movable part . As a result, the origin setting device can move the linear motor relatively fast and with low accuracy to roughly temporarily set the origin, and then move the linear motor relatively slowly and with high accuracy to set the origin.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0009] The following describes the embodiments in the following order. <1. Linear motor> [1.1 Configuration of the linear motor] [1.2 Configuration of the linear motor system] [1.3 Control of the linear motor] [1.4 Origin setting process] [1.5 Temporary origin setting process] [1.6 True origin setting process] [1.7 Specific example of the origin setting process] <2. Application examples of the linear motor system> <3. Modification examples> <4. Summary of the embodiments> <5. This technology>

[0010] <1. Linear motor> [1.1 Configuration of the linear motor] FIG. 1 is a diagram for explaining the configuration of a linear motor 1 as an embodiment according to the present technology. As shown in FIG. 1, the linear motor 1 includes a fixed portion 2 and a movable portion 3. The movable portion 3 is relatively movable with respect to the fixed portion 2. Hereinafter, the moving direction of the movable portion 3 may be referred to as the movable direction. In the embodiment, the movable portion 3 moves in the left-right direction in FIG. 1.

[0011] The fixed portion 2 includes a fixed support portion 11, a permanent magnet 12, regulating members 13a and 13b, an origin detection sensor 14, and a position detection sensor 15. The fixed support portion 11 is a member for supporting other components of the fixed portion 2, and supports the permanent magnet 12, the regulating members 13a and 13b, the origin detection sensor 14, and the position detection sensor 15. Note that the origin detection sensor 14 and the position detection sensor 15 may be provided on the movable portion 3.

[0012] The permanent magnet 12 is provided with a permanent magnet having an N pole disposed on the fixed portion 2 side (hereinafter referred to as an N pole magnet) and a permanent magnet having an S pole disposed on the fixed portion 2 side (hereinafter referred to as an S pole magnet).

[0013] The permanent magnets 12 are arranged such that the N - pole magnets and the S - pole magnets are alternately arranged along the moving direction. In FIG. 1, six permanent magnets 12 are provided, but the number can be any number. Also, as long as the N - pole and the S - pole are alternately generated along the moving direction, other arrangements may be used.

[0014] The restricting members 13a and 13b are arranged to face the movable part 3 in the moving direction and function as so - called mechanical ends. The restricting member 13a abuts when the movable part 3 moves leftward in FIG. 1 and restricts further movement in the leftward direction. The restricting member 13b abuts when the movable part 3 moves rightward in FIG. 1 and restricts further movement in the rightward direction. That is, the movable part 3 can move in the moving direction within the movable range between the restricting member 13a and the restricting member 13b.

[0015] The origin detection sensor 14 is, for example, a photo - interrupter having a pair of light - emitting elements and light - receiving elements, and is arranged to face the movable part 3 at a predetermined position in the moving direction, and outputs origin detection signals of different values (high, low) depending on the position of the movable part 3 with respect to a predetermined position.

[0016] For example, the origin detection sensor 14 outputs a high origin detection signal when the movable part 3 is on the left side of the predetermined position in FIG. 1, and outputs a low origin detection signal when the movable part 3 is on the right side of the predetermined position in FIG. 1. Note that the origin detection sensor 14 may be a sensor other than a photo - interrupter as long as it can output origin detection signals of different values depending on the position of the movable part 3 with respect to a predetermined position.

[0017] The position detection sensor 15 is, for example, an incremental - type sensor and is arranged to face the movable part 3 at a predetermined position in the moving direction. A magnet sheet with magnetic marks provided at predetermined intervals is attached to the surface of the movable part 3 that faces the position detection sensor 15.

[0018] When the movable part 3 moves from the regulating member 13a side to the regulating member 13b side, the position detection sensor 15 adds a counter each time it detects the magnetism emitted from the magnetic mark of the magnetic sheet. Also, when the movable part 3 moves from the regulating member 13b side to the regulating member 13a side, the position detection sensor 15 subtracts the counter each time it detects the magnetism emitted from the magnetic mark of the magnetic sheet. Then, the position detection sensor 15 outputs the counter value of the added or subtracted counter as a position detection signal.

[0019] Note that the position detection sensor 15 may be an incremental type sensor, for example, it may be a sensor that outputs a position detection signal each time it detects an optical mark. Also, when the position detection sensor 15 detects an optical mark, an optical scale provided with optical marks at predetermined intervals may be attached to the movable part 3.

[0020] The movable part 3 includes a movable support part 21 and a coil 22. The movable part 3 is supported so as to be movable only in the movable direction while maintaining a distance from the permanent magnet 12 by, for example, a guide rail (not shown).

[0021] The movable support part 21 supports the coil 22. Also, a magnetic sheet is attached to the surface of the movable support part 21 facing the position detection sensor 15.

[0022] A current of a predetermined electrical angle (phase) in a sine wave shape is passed through the coil 22 by being PWM (Pulse Width Modulation) controlled. Specifically, the coil 22 receives an excitation signal of an excitation pattern corresponding to a predetermined electrical angle in a sine wave shape, and is energized in an excitation pattern based on the input excitation signal.

[0023] The coil 22 is provided with a phase A coil 22a and a phase B coil 22b to which excitation signals having an electrical angle difference of 90° (see FIG. 5) are input. The phase A coil 22a and the phase B coil 22b face the permanent magnet 12 and are supported by the movable support portion 21 so as to be aligned in the movable direction. When an excitation signal is input, the coil 22 is energized and magnetized, and generates a magnetic field.

[0024] The movable part 3 moves in the movable direction by the magnetic field or current generated when the coil 22 is energized in the excitation pattern and the magnetic field generated by the permanent magnet 12.

[0025] [1.2 Configuration of Linear Motor System] FIG. 2 is a diagram for explaining the configuration of the linear motor system 30. As shown in FIG. 2, a linear motor system 30, which is an example of a origin setting device in the embodiment including the linear motor 1, includes a host control unit 31, a motor drive control unit 32, and an electric circuit 33.

[0026] The host control unit 31 is an integrated circuit (IC: Integrated Circuit) that comprehensively controls the linear motor system 30, and comprehensively drives and controls the linear motor 1.

[0027] The motor drive control unit 32 is an integrated circuit (IC: Integrated Circuit) that drives and controls the linear motor 1 together with the host control unit 31, and functions as a stepper drive signal generation unit 41, a linear drive signal generation unit 42, a selection unit 43, a position detection unit 44, and a position control unit 45.

[0028] The motor drive control unit 32 is connected to the host control unit 31, and drives and controls the linear motor 1 based on various signals output from the host control unit 31. Note that the host control unit 31 may be provided in the same integrated circuit as the motor drive control unit 32.

[0029] The stepper drive signal generation unit 41 outputs a stepper drive signal of an excitation pattern based on the target position signal input from the upper control unit 31 to the selection unit 43. The target position signal is a signal indicating the target position that is the movement target of the movable unit 3.

[0030] When the coil 22 is energized with an excitation pattern based on the stepper drive signal, the movable unit 3 is pulled into a stable position where the attractive and repulsive forces between the magnetic field generated by the coil 22 and the magnetic field generated by the permanent magnet 12 are balanced and stops. In this way, the drive method of driving the linear motor 1 based on the stepper drive signal is referred to as stepper drive.

[0031] Stepper drive has the same drive principle as a stepping motor and can move the movable unit 3 to the target position by open-loop control in which the coil 22 is energized with a predetermined excitation pattern. Therefore, it can be driven even when the position of the movable unit 3 is indefinite. Also, although the movement accuracy of stepper drive is lower compared to the linear drive described later, the movable unit 3 can be moved at high speed.

[0032] The linear drive signal generation unit 42 outputs a linear drive signal of an excitation pattern in which the Lorentz force generated in the coil 22 is maximized, based on the target position signal input from the upper control unit 31 and the position of the movable unit 3 detected by the position detection sensor 15, to the selection unit 43. When the coil 22 is energized with an excitation pattern based on the linear drive signal, the movable unit 3 moves by the Lorentz force generated in the coil 22. In this way, the drive method of driving the linear motor 1 based on the linear drive signal is referred to as linear drive.

[0033] Since linear drive can move the movable unit 3 to the target position by closed-loop control (feedback control), compared to stepper drive, the movement accuracy is high while the movable unit 3 is moved at a low speed. Therefore, in the origin setting process described later, linear drive can cross the movable unit 3 at a controlled speed with high position accuracy at the position where the origin detection signal switches.

[0034] Based on the selection signal input from the upper control unit 31, the selection unit 43 outputs one of the stepper drive signal input from the stepper drive signal generation unit 41 and the linear drive signal input from the linear drive signal generation unit 42 to the electric circuit 33 as a control signal.

[0035] When the position detection unit 44 acquires the origin detection signal and the position detection signal input from the signal processing circuit 52 described later, it outputs the acquired origin detection signal and position detection signal to the upper control unit 31.

[0036] Further, the position detection unit 44 calculates the position of the movable part 3 in the absolute coordinate system (the position based on the counter value with the origin as a reference) based on the origin detection signal and the position detection signal, and outputs a position signal indicating the calculated position to the position control unit 45.

[0037] Furthermore, the position detection unit 44 calculates the electrical angle according to the calculated position of the movable part 3 in the absolute coordinate system and outputs it to the linear drive signal generation unit 42 as a phase signal.

[0038] When the position control unit 45 acquires the target signal from the upper control unit 31 and the position detection signal from the position detection unit 44, it calculates the deviation between the target position and the position of the movable part 3 in the absolute coordinate system based on the target signal and the position detection signal. Then, the position control unit 45 determines the amplitude (the amplitude of the sine wave) of the voltage applied to the coil 22 in order to minimize the calculated deviation, and outputs an amplitude signal indicating the determined amplitude to the linear drive signal generation unit 42.

[0039] Therefore, in the linear drive signal generation unit 42, an excitation pattern with the electrical angle indicated by the phase signal acquired from the position detection unit 44 and the amplitude corresponding to the amplitude signal acquired from the position control unit 45 will be determined.

[0040] The electric circuit 33 includes a drive circuit 51 and a signal processing circuit 52. When the drive circuit 51 acquires the control signal input from the selection unit 43 of the motor drive control unit 32, it generates an excitation signal for driving the coil 22 in the excitation pattern indicated by the control signal and outputs it to the coil 22. Thereby, the coil 22 will be energized in the excitation pattern.

[0041] When the signal processing circuit 52 acquires the origin detection signal from the origin detection sensor 14 and the position detection signal from the position detection sensor 15, it amplifies these signals and outputs them to the position detection unit 44.

[0042] [1.3 Control of Linear Motor] In the linear motor system 30, when the origin of the movable part 3 is set, a control signal for selecting linear drive is input from the upper control unit 31 to the selection unit 43. Therefore, in the linear motor system 30, based on the selection signal, the selection unit 43 selects a linear drive signal and outputs it to the electric circuit 33 as a control signal, so the linear motor 1 will be linearly driven. Thereby, the linear motor 1 can accurately move the movable part 3.

[0043] However, when the origin of the movable part 3 is not set, such as when the power is turned on, the linear motor 1 cannot be driven by linear drive. Therefore, first, it is necessary to set the origin of the movable part 3.

[0044] Therefore, in the linear motor system 30 of this embodiment, when setting the origin, the following origin setting process is executed.

[0045] [1.4 Origin Setting Process] FIG. 3 is a flowchart showing the flow of the origin setting process. In the linear motor system 30, when the power is turned on, the origin setting process shown in FIG. 3 is executed.

[0046] In step S1, the upper control unit 31 executes a temporary origin setting process of driving the linear motor 1 in a stepper drive mode to set a temporary origin. The details of the temporary origin setting process will be described later.

[0047] When the temporary origin setting process ends, in step S2, the upper control unit 31 executes a drive mode switching process of switching the drive of the linear motor 1 from stepper drive to linear drive.

[0048] When the drive mode switching process ends, in step S3, the upper control unit 31 executes an actual origin setting process of driving the linear motor 1 in a linear drive mode to set an origin. The details of the actual origin setting process will be described later.

[0049] [1.5 Temporary Origin Setting Process] FIG. 4 is a flowchart showing the flow of the temporary origin setting process. When the temporary origin setting process starts, in step S11, the upper control unit 31 outputs a selection signal for selecting stepper drive to the selection unit 43. As a result, in the linear motor system 30, it becomes possible to drive the linear motor 1 based on the stepper drive signal generated by the stepper drive signal generation unit 41.

[0050] Subsequently, in step S12, the upper control unit 31 outputs a target position signal indicating a predetermined initial target position to the stepper drive signal generation unit 41. When receiving the target position signal, the stepper drive signal generation unit 41 determines an initial excitation pattern for moving the movable part 3 to the initial target position indicated by the target position signal.

[0051] Here, the initial excitation pattern differs according to the value (high, low) of the origin detection signal detected by the origin detection sensor 14.

[0052] Figures 5 to 9 are diagrams for explaining the initial excitation pattern. In Figures 5 to 9, the electrical angle (phase) of the A-phase coil 22a is indicated by a thin line, and the electrical angle (phase) of the B-phase coil 22b is indicated by a thick line. As shown in Figure 5, the initial target position is determined in advance according to the value of the origin detection signal detected by the origin detection sensor 14, that is, the position of the movable part 3.

[0053] And the initial target positions are respectively set to positions corresponding to less than 180° of electrical angle from the restricting members 13a and 13b toward the movable range side. Therefore, the initial excitation pattern is set to a value shifted by less than 180° of electrical angle from the restricting members 13a and 13b toward the movable range side.

[0054] As described above, it is unknown where the movable part 3 is located when the power is turned on. Therefore, the initial excitation pattern is set so that the movable part 3 does not collide with the restricting members 13a and 13b when the coil 22 is energized, that is, so that the movable part 3 is drawn into the moving range.

[0055] And as shown in Figure 5, when the movable range of the movable part 3 is less than one cycle of the electrical angle and the origin detection signal switches at a position where the electrical angle is 90° or more from the restricting members 13a and 13b, the initial excitation pattern (initial target position) when the origin detection signal is high is set to a value shifted by 90° of electrical angle from the restricting member 13a toward the movable range side (right side). Note that 90° of electrical angle is the angle at which the most thrust is generated on the movable part 3 by the excitation of the coil 22.

[0056] Also, the initial excitation pattern when the origin detection signal is low is set to a value shifted by 90° of electrical angle from the restricting member 13b toward the movable range side (left side).

[0057] By setting the initial excitation pattern in this way, no matter where the movable part 3 is located, the movable part 3 will be attracted to a position shifted by 90° of electrical angle from the restricting members 13a and 13b toward the movable range side.

[0058] Also, as shown in FIG. 6, when the movable range of the coil 22 is less than one cycle of the electrical angle and the origin detection signal switches at a position where the electrical angle is less than 90° from the regulating member 13a, the initial excitation pattern when the origin detection signal is high is set to a value with an electrical angle shift of 90° to the movable range side (right side) from the regulating member 13a.

[0059] Also, the initial excitation pattern when the origin detection signal is low is set to a value with an electrical angle less than 180° to the movable range side (left side) from the regulating member 13b and an electrical angle less than 180° from the position (predetermined position) where the origin detection signal switches to the regulating member 13b side. That is, the initial excitation pattern when the origin detection signal is low is set to a value that draws the movable part 3 to the initial target position regardless of the position of the movable part 3.

[0060] By setting the initial excitation pattern in this way, the movable part 3 will be moved within the movable range regardless of its position.

[0061] Also, as shown in FIG. 7, when the movable range of the coil 22 is less than one cycle of the electrical angle and the positions with an electrical angle shift of 90° from both the regulating members 13a and 13b cross, the initial excitation pattern when the origin detection signal is high is set to a value with an electrical angle shift of 90° to the movable range side (right side) from the regulating member 13a.

[0062] Also, the initial excitation pattern when the origin detection signal is low is set to a value with an electrical angle shift of 90° to the movable range side (left side) from the regulating member 13b.

[0063] By setting the initial excitation pattern in this way, the movable part 3 will be moved to a position with an electrical angle shift of 90° to the movable part 3 side from the regulating members 13a and 13b regardless of the position of the movable part 3.

[0064] Also, as shown in FIG. 8, when the movable range of the coil 22 is one or more electrical angle cycles, the initial excitation pattern when the origin detection signal is high is set to a value with an electrical angle shift of 90° from the regulating member 13a toward the movable range side (right side).

[0065] Also, the initial excitation pattern when the origin detection signal is low is set to a value with an electrical angle shift of 90° from the regulating member 13b toward the movable range side (left side).

[0066] By setting the initial excitation pattern in this way, no matter where the movable part 3 is located, the movable part 3 will move to a position with an electrical angle shift of 90° from the regulating members 13a and 13b toward the movable range side, or to a position with an electrical angle shift of 360° from the initial target position within the movable range.

[0067] Returning to FIG. 4, in step S13, the upper control unit 31 determines whether the value of the origin detection signal detected by the origin detection sensor 14 has changed. Here, it is determined whether the movable part 3 has passed in front of the origin detection sensor 14 by the initial excitation.

[0068] And when the value of the origin detection signal has changed (Yes in step S13), the upper control unit 31 stores the counter value (the counter value detected by the position detection sensor 15) when the value of the origin detection signal has changed, skips the processes of steps S14 to S16, and moves the process to step S17.

[0069] On the other hand, when the value of the origin detection signal has not changed (No in step S13), in step S14, the upper control unit 31 outputs a target position signal indicating a position for moving the movable part 3 in the direction where the origin detection sensor 14 is provided (the direction in which the value output from the origin detection sensor 14 becomes different) to the stepper drive signal generation unit 41. Thereby, the linear motor 1 moves the movable part 3 toward the origin detection sensor 14 at high speed by stepper drive. Note that in stepper drive, the movable part 3 is driven at a speed that does not cause out-of-step.

[0070] Subsequently, in step S15, the upper control unit 31 determines whether the value of the origin detection signal detected by the origin detection sensor 14 has changed. Here, it is determined whether the movable unit 3 has passed in front of the origin detection sensor 14 by stepping drive.

[0071] Then, until the origin detection signal changes (No in step S15), steps S14 and S15 are repeatedly executed. When the value of the origin detection signal changes (Yes in step S15), in step S16, the upper control unit 31 stores the counter value when the origin detection signal changes, and outputs a target signal and a selection signal to the stepper drive signal generation unit 41 and the selection unit 43 so as to stop the linear motor 1. As a result, the linear motor 1 stops.

[0072] In step S17, the upper control unit 31 sets the position of the movable unit 3 corresponding to the counter value when the origin detection signal changes as a temporary origin, sets a temporary phase used in linear drive with reference to the temporary origin, and ends the temporary origin setting process. Thereafter, as described above, after the drive mode switching process is performed in step S2, the true origin setting process is performed in step S3.

[0073] [1.6 True Origin Setting Process] FIG. 9 is a flowchart showing the flow of the true origin setting process. When starting the true origin setting process, in step S21, the upper control unit 31 outputs a target position signal indicating a position for moving the movable unit 3 in the direction where the origin detection sensor 14 is provided to the linear drive signal generation unit 42. As a result, the linear motor 1 moves the movable unit 3 to the origin detection sensor 14 side by linear drive.

[0074] Subsequently, in step S22, the upper control unit 31 determines whether the value of the origin detection signal detected by the origin detection sensor 14 has changed. Here, it is determined whether the movable unit 3 has passed in front of the origin detection sensor 14 by linear drive.

[0075] Then, until the value of the origin detection signal changes (No in step S22), step S21 is repeatedly executed. When the value of the origin detection signal changes (Yes in step S22), in step S23, the host control unit 31 stores the counter value when the origin detection signal changes, and outputs a target signal and a selection signal to the linear drive signal generation unit 42 and the selection unit 43 so as to stop the linear motor 1. As a result, the linear motor 1 stops.

[0076] In step S24, the host control unit 31 sets the position of the movable part 3 corresponding to the counter value when the value of the origin detection signal changes as the origin, and sets the phase (phase in the absolute coordinate system) used in the linear drive with the origin as a reference, and ends this origin setting process.

[0077] [1.7 Specific Example of Origin Setting Process] FIG. 10 is a diagram for explaining a specific example of the origin setting process. As shown in FIG. 10, when the power is turned on, the movable part 3 is located on the side of the regulating member 13a, and it is assumed that the detection signal from the origin detection sensor 14 is high.

[0078] In such a case, the origin setting process is started. When the linear motor 1 is driven in the initial excitation pattern in the temporary origin setting process, as shown by the arrow A1, the movable part 3 moves toward the origin detection sensor 14 side (the direction in which the value of the origin detection signal changes). Then, as shown by the arrow A2, the movable part 3 is moved toward the origin detection sensor 14 side by the stepper drive. When the value of the origin detection signal changes, the movable part 3 is stopped. And the position when the value of the origin detection signal changes is set as the temporary origin P1. However, since the movable part 3 is controlled to move at high speed by the stepper drive for the temporary origin P1, the accuracy is not very good.

[0079] After that, when switching from stepper drive to linear drive, as shown by arrow A3, the movable part 3 may move slightly. Then, as shown by arrow A4, when the movable part 3 is moved toward the origin detection sensor 14 by linear drive and the value of the origin detection signal changes, the movable part 3 is stopped. At this time, the position when the value of the origin detection signal changes is set as the origin P2. However, since the movable part 3 is accurately moved and controlled at a low speed by linear drive, the origin P2 has high accuracy.

[0080] As described above, in the linear motor system 30, after driving the linear motor 1 at high speed by stepper drive to set the temporary origin P1, the linear motor 1 is driven at low speed and with high accuracy by linear drive to set the origin P2. Thereby, the linear motor system 30 can set the origin accurately at an early stage.

[0081] <2. Application Examples of Linear Motor System> FIG. 11 is a diagram for explaining the configuration of an imaging device which is an application example of the linear motor system 30. The above-described linear motor 1 can be considered to be adapted as an actuator for moving lenses of an imaging device such as a digital still camera, specifically, a focus lens, a zoom lens, a diaphragm mechanism, a shake correction lens, etc. Here, the case where the linear motor 1 is adapted as an actuator for driving the focus lens of the camera will be described.

[0082] As shown in FIG. 11, the imaging device 100 includes a main body part 101 and an interchangeable lens 102. The imaging device 100 can attach and detach the interchangeable lens 102 with respect to the main body part 101. Note that the imaging device 100 may be an integrated type in which the interchangeable lens 102 cannot be attached and detached with respect to the main body part 101.

[0083] The main body part 101 captures a subject to generate image data, and records the generated image data as image content (still image content or moving image content).

[0084] The interchangeable lens 102 is an interchangeable lens unit attached to the main body 101. The interchangeable lens 102 includes a zoom lens 211, a zoom position detection unit 212, a focus lens 221, a focus lens drive motor 222, a diaphragm mechanism 231, a diaphragm drive motor 232, a motor driver 240, and a lens control unit 250. It also includes a ROM 260 (Read Only Memory) and a RAM (Random Access Memory) 270. It further includes an interface unit 201.

[0085] The zoom lens 211 is a lens that moves in the optical axis direction by either electric or manual drive to adjust the focal length. That is, the zoom lens 211 is a lens that drives forward and backward with respect to the subject in order to enlarge or reduce the subject included in the captured image. Also, the zoom function is realized by the zoom lens 211.

[0086] The zoom position detection unit 212 detects the position of the zoom lens 211 driven by a zoom operation by the user, and outputs the detection result to the lens control unit 250.

[0087] The focus lens 221 is a lens that moves in the optical axis direction by the drive of the focus lens drive motor 222 to adjust the focus. That is, the focus lens 221 is a lens used to focus on the subject (bring it into focus). Also, the autofocus function is realized by the focus lens 221.

[0088] The focus lens drive motor 222 drives the focus lens 221 based on the control of the motor driver 240.

[0089] The diaphragm mechanism 231 adjusts the amount of incident light passing through the zoom lens 211 and the focus lens 221, and the adjusted light is supplied to the imaging element 111. The diaphragm mechanism 231 is driven by the diaphragm drive motor 232, and the aperture opening is adjusted.

[0090] The aperture drive motor 232 drives the aperture mechanism 231 based on the control of the motor driver 240.

[0091] That is, the zoom lens 211 and the focus lens 221 are lens groups that condense incident light from the subject, and the light condensed by these lens groups is incident on the imaging element 111 through the aperture mechanism 231.

[0092] The motor driver 240 drives the focus lens drive motor 222 and the aperture drive motor 232 based on the control of the lens control unit 250.

[0093] The lens control unit 250 controls each part (such as the focus lens 221 and the aperture mechanism 231) that constitutes the interchangeable lens 102. The lens control unit 250 is constituted by, for example, a CPU (Central Processing Unit).

[0094] The ROM 260 stores unique information regarding each member that constitutes the interchangeable lens 102, and programs to be executed by the CPU as the lens control unit 250, etc. The RAM 270 is used as a work area when the lens control unit 250 executes arithmetic processing. The interface unit 201 communicates with the main body unit 101.

[0095] Next, the main body 101 includes a system bus 180, an imaging device 111, an analog signal processing unit 112, and an A / D (Analog / Digital) conversion unit 113. Further, the main body 101 includes a digital signal processing unit 114, a display unit 115, and a recording device 116. Further, the main body 101 includes a vertical driver 117, a timing generator 118, an operation unit 120, and a control unit 130. Further, the main body 101 includes an EEPROM (Electrically Erasable and Programmable Read Only Memory) 140, a ROM (Read Only Memory) 150, and a RAM (Random Access Memory) 160. Further, the main body 101 includes and an interface unit 119. Further, the main body 101 includes a detection unit 170.

[0096] Note that the digital signal processing unit 114, the vertical driver 117, the timing generator 118, the operation unit 120, and the detection unit 170 are connected via the system bus 180 so as to be communicable with, for example, the control unit 130 and the like. Also, the EEPROM 140, the ROM 150, and the RAM 160 are connected via the system bus 180 so as to be communicable with the control unit 130 and the like.

[0097] The imaging device 111 is a photoelectric conversion element that receives light (incident light) supplied via a zoom lens 211, a focus lens 221, and a diaphragm mechanism 231, converts this incident light into an electrical signal, and supplies the converted electrical signal to the analog signal processing unit 112. Further, the imaging device 111 is driven by the vertical driver 117. Note that, as the imaging device 111, for example, a CCD (Charge Coupled Device) sensor, a CMOS (Complementary Metal Oxide Semiconductor) sensor, or the like can be used.

[0098] The analog signal processing unit 112 performs analog signal processing such as noise removal processing on the electrical signal supplied from the imaging device 111 according to the timing instructed by the timing generator 118. The analog signal on which the analog signal processing has been performed by the analog signal processing unit 112 is supplied to the A / D conversion unit 113.

[0099] The A / D conversion unit 113 converts the analog signal supplied from the analog signal processing unit 112 into a digital signal according to the timing instructed by the timing generator 118, and supplies the converted digital signal to the digital signal processing unit 114.

[0100] The digital signal processing unit 114 performs image processing such as black level correction, white balance adjustment, and gamma correction on the digital signal supplied from the A / D conversion unit 113 based on the control of the control unit 130. Then, the digital signal processing unit 114 supplies the image data on which the image processing has been performed to the display unit 115 and the recording device 116. For example, the digital signal processing unit 114 performs compression processing on the image data on which the image processing has been performed, and supplies the image data (compressed image data) on which this compression processing has been performed to the recording device 116. As the compression method, for example, the JPEG (Joint Photographic Experts Group) method can be adopted. Also, it is possible to supply the image data in the RAW data format without compression processing to the recording device 116. Further, the digital signal processing unit 114 performs decompression processing on the compressed image data recorded in the recording device 116, and supplies the image data on which this decompression processing has been performed to the display unit 115. Note that the digital signal processing unit 114 can be realized by a signal processing device as a DSP (Digital Signal Processor).

[0101] The display unit 115 is a display device that displays the image data supplied from the digital signal processing unit 114. The display unit 115, for example, displays the image data subjected to image processing by the digital signal processing unit 114 as a through image. Further, for example, the display unit 115 displays the image data recorded in the recording device 116 as a list image. As the display unit 115, for example, a display panel such as an organic EL (Electro Luminescence) panel or an LCD (Liquid Crystal Display) can be used.

[0102] The recording device 116 records the image data subjected to image processing by the digital signal processing unit 114. Further, the image data recorded in the recording device 116 is supplied to the digital signal processing unit 114. Note that the recording device 116 may be built into the main body unit 101 or may be detachable from the main body unit 101. Further, as the recording device 116, various devices such as a semiconductor memory, an optical recording medium, a magnetic disk, and an HDD (Hard Disk Drive) can be used. Note that as the optical recording medium, for example, a recordable DVD (Digital Versatile Disc), a recordable CD (Compact Disc), a Blu-ray Disc (registered trademark), etc. can be used.

[0103] The vertical driver 117 drives the imaging element 111 based on the control of the control unit 130. The timing generator 118 indicates the operation timing in each of the analog signal processing unit 112 and the A / D conversion unit 113 based on the reference clock supplied from the control unit 130. Specifically, this indication of the operation timing is performed, for example, by outputting a timing signal generated based on the above reference clock to the analog signal processing unit 112 and the A / D conversion unit 113.

[0104] The operation unit 120 is provided with operation members such as buttons and switches for performing various operations, receives operation inputs from the user, and outputs the content of the received operation inputs to the control unit 130 via the system bus 180. In addition to the operation members such as buttons arranged on the outer surface of the main body unit 101, a touch panel may be provided on the display unit 115 to receive operation inputs from the user on the touch panel.

[0105] The EEPROM 140 is a memory that retains data even when the main body unit 101 is powered off, and various setting conditions and the like are recorded therein. The ROM 150 is a non-volatile memory that stores programs and various data to be executed by the control unit 130. The RAM 160 is a volatile memory that holds data to be temporarily retained and rewritable data when the control unit 130 operates, and is used, for example, as a working memory when the control unit 130 operates.

[0106] The interface unit 119 executes communication with the interchangeable lens 102 by being connected to the interface unit 201 on the side of the interchangeable lens 102 attached to the main body unit 101.

[0107] The control unit 130 is composed of, for example, a CPU that executes programs stored in the ROM 150, and is a part that controls each part of the main body unit 101 based on each piece of information stored in the ROM 150. The control unit 130 controls, for example, exposure, white balance, focus, flash emission, etc. Also, for example, at the time of imaging, the control unit 130 generates a control signal based on the user's operation input from the operation unit 120 and the image information from the digital signal processing unit 114. Then, the generated control signal is output to the motor driver 240, the vertical driver 117, the timing generator 118, etc., and by operating the focus lens 221, the aperture mechanism 231, etc., control of exposure, white balance, focus, flash, etc. is performed.

[0108] Also, when the control unit 130 records the image data that has been subjected to image processing by the digital signal processing unit 114, it outputs a control signal to the digital signal processing unit 114 based on the user's operation input from the operation unit 120. Then, the digital signal processing unit 114 records the compressed image data as a still image file in the recording device 116. Also, when the control unit 130 displays the still image file recorded in the recording device 116, it outputs a control signal to the digital signal processing unit 114 based on the user's operation input from the operation unit 120. Then, it causes the display unit 115 to display an image corresponding to the still image file recorded in the recording device 116.

[0109] The detection unit 170 performs detection to extract the contrast component from the image signal in correspondence with the autofocus control by the contrast method employed by the main body unit 101, and obtains an evaluation value regarding the contrast. The control unit 130 executes autofocus control to move the focus lens 221 so as to be in the in-focus state based on the evaluation value generated by the detection unit 170. In actuality, the detection unit 170 may be configured as, for example, one function executed by the digital signal processing unit 114. Alternatively, it may be configured such that at least a part of the signal processing function is executed by the control unit 130.

[0110] In the imaging device 100 having such a configuration, the linear motor 1 can be adapted as the focus lens drive motor 222 that drives the focus lens 221. Specifically, the focus lens 221 is fixed to the movable part 3 of the linear motor 1, and the focus lens 221 is moved together with the movable part 3.

[0111] Also, in the imaging device 100, the motor driver 240 can be adapted as the drive circuit 51 of the electric circuit 33. Further, in the imaging device 100, the lens control unit 250 can be adapted as the upper control unit 31 and the motor drive control unit 32.

[0112] By doing so, when the imaging device 100 is activated, it becomes possible to set the origin of the focus lens 221 quickly and accurately. In the imaging device 100, the power is repeatedly turned on and off, and it is desired to set the origin early, which is particularly useful.

[0113] <3. Modification Example> Note that the embodiment is not limited to the specific examples described above, and configurations as various modification examples can be adopted.

[0114] For example, in the embodiment, the linear motor system 30 is applied to the imaging device 100, but the linear motor system 30 may be applied to other devices.

[0115] Also, in the embodiment, the upper control unit 31 and the motor drive control unit 32 are provided as separate functional units, and they function as the control unit of the embodiment. However, the upper control unit 31 and the motor drive control unit 32 may be provided as one functional unit and function as the control unit of the embodiment.

[0116] Also, in the embodiment, the permanent magnet 12 is provided in the fixed part 2, and the coil 22 is provided in the movable part 3. However, the coil 22 may be provided in the fixed part 2, and the permanent magnet 12 may be provided in the movable part 3.

[0117] <4. Summary of the Embodiment> As described above, in the origin setting device (linear motor system 30) of the embodiment, a control unit (upper control unit 31, motor drive control unit 32) for setting the origin of the movable part 3 of the linear motor 1 is provided by driving the linear motor 1 in two different driving methods. Thereby, the origin setting device can set the origin by moving the linear motor 1 relatively quickly and with low accuracy to roughly set a temporary origin, and then moving the linear motor 1 relatively slowly and with high accuracy. Therefore, the origin setting device can set the origin of the movable part 3 in a short time with high precision.

[0118] Also, the drive method may include a first drive method (stepper drive) for driving the linear motor 1 in open-loop control and a second drive method (linear drive) for driving the linear motor 1 in closed-loop control. Thereby, after the origin setting device moves the linear motor 1 relatively fast and with low precision in open-loop control to roughly set a temporary origin, it can move the linear motor 1 relatively slowly and with high precision in closed-loop control to set the origin.

[0119] Also, it is conceivable that in the first drive method, the coil 22 of the linear motor 1 is energized with a predetermined excitation pattern, and in the second drive method, the coil 22 of the linear motor 1 is energized with an excitation pattern corresponding to the position of the movable part 3. Thereby, after the origin setting device moves the linear motor 1 relatively fast and with low precision with an excitation pattern to roughly set a temporary origin, it can move the linear motor 1 relatively slowly and with high precision with an excitation pattern to set the origin.

[0120] Also, it is conceivable that the control unit (upper control unit 31, motor drive control unit 32) drives the linear motor 1 in the first drive method and then drives the linear motor in the second drive method. Thereby, after moving the linear motor 1 by stepper drive, it becomes possible to move the linear motor 1 by linear drive.

[0121] Also, the initial excitation pattern of the first drive method may be set to a value deviated by less than 180° in electrical angle to the movable range side where the movable part 3 can move from the restricting members 13a and 13b that restrict the movement of the movable part 3. Thereby, when the coil 22 is energized with the initial excitation pattern, it is possible to reduce the possibility that the movable part 3 collides with the restricting members 13a and 13b.

[0122] Further, an origin detection sensor 14 that outputs different values depending on the position of the movable part 3 with a predetermined position as a boundary is provided, and it is conceivable that the initial excitation pattern is set for each output value of the origin detection sensor. Thereby, regardless of the output value of the origin detection sensor, it is possible to reduce the possibility that the movable part 3 collides with the regulating members 13a and 13b when the coil 22 is energized in the initial excitation pattern.

[0123] Also, the control unit (upper control unit 31, motor drive control unit 32) energizes the coil 22 of the linear motor 1 in the initial excitation pattern, and when the value output from the origin detection sensor 14 is the same before and after energization, the linear motor 1 is driven in the first driving method in a direction such that the value output from the origin detection sensor 14 becomes different. When the value output from the origin detection sensor 14 is different, it is conceivable to terminate the first driving method and stop the linear motor 1. Thereby, if the value output from the origin detection sensor 14 does not change when the coil 22 is energized in the initial excitation pattern, it becomes possible to drive the linear motor 1 in the first driving method (stepper drive) to set a temporary origin. Thereby, the origin of the movable part 3 can be set at an early stage.

[0124] Also, the control unit (upper control unit 31, motor drive control unit 32) energizes the coil 22 of the linear motor 1 in the initial excitation pattern, and when the value output from the origin detection sensor 14 is different before and after energization, it is conceivable to terminate the first driving method and stop the linear motor 1. Thereby, if the value output from the origin detection sensor 14 changes when the coil 22 is energized in the initial excitation pattern, it becomes possible to set the switched position as a temporary origin without performing the first driving method (stepper drive). Thereby, the origin of the movable part 3 can be set even earlier.

[0125] Further, after terminating the first driving method, the control unit (the upper control unit 31 and the motor drive control unit 32) may drive the linear motor in the second driving method so as to move the movable part in a direction in which the value output from the origin detection sensor 14 becomes different. By driving the linear motor in the second driving method in this way, it becomes possible to accurately set the origin.

[0126] Further, while driving the linear motor 1 in the second driving method, the control unit (the upper control unit 31 and the motor drive control unit 32) may set a position where the value output from the origin detection sensor 14 is different as the origin. By driving the linear motor in the second driving method in this way, it becomes possible to accurately set the origin.

[0127] Further, while driving the linear motor 1 in the second driving method, if the value output from the origin detection sensor 14 is different, the control unit (the upper control unit 31 and the motor drive control unit 32) may terminate the second driving method and stop the linear motor 1. This makes it possible to terminate the origin setting process at an early stage.

[0128] Further, the initial excitation pattern of the first driving method may be set to a value with an electrical angle shifted by 90° to the movable range side where the movable part 3 can move from the restricting members 13a and 13b that restrict the movement of the movable part 3. This makes it possible to most efficiently draw the movable part 3 to the initial target position.

[0129] Further, the linear motor 1 may be an actuator (focus lens drive motor 222) provided in the lens unit (interchangeable lens 102) of the imaging device 100. This makes it possible to early and accurately set the origin of the actuator provided in the lens unit.

[0130] In addition, the linear motor 1 can be considered to drive the lens (focus lens 221) of the imaging device 100. Thereby, the origin of the actuator that drives the lens of the imaging device 100 can be set early and with high accuracy.

[0131] As described above, the origin setting method of the embodiment sets the origin of the movable part 3 of the linear motor 1 by driving the linear motor 1 in two different driving methods.

[0132] Note that the effects described in this specification are merely examples and are not limited, and there may be other effects.

[0133] <5. This technology> This technology can also adopt the following configuration. (1) A control unit that sets the origin of the movable part of the linear motor by driving the linear motor in two different driving methods An origin setting device including the same. (2) The driving method includes A first driving method of driving the linear motor by open-loop control, and a second driving method of driving the linear motor by closed-loop control The origin setting device according to (1). (3) The first driving method energizes the coil of the linear motor with a predetermined excitation pattern, The second driving method energizes the coil of the linear motor with an excitation pattern corresponding to the position of the movable part The origin setting device according to (2). (4) The control unit drives the linear motor by the first driving method and then drives the linear motor by the second driving method The origin setting device according to (3). (5) The initial excitation pattern of the first driving method is set to a value that is less than 180° in electrical angle toward the movable range side where the movement of the movable part is possible from a regulating member that restricts the movement of the movable part. The origin setting device according to (3) or (4). (6) It includes an origin detection sensor that outputs different values depending on the position of the movable part with a predetermined position as a boundary. The initial excitation pattern is set respectively for each output value of the origin detection sensor. The origin setting device according to (5). (7) The control unit energizes the coil of the linear motor with the initial excitation pattern, and when the values output from the origin detection sensor before and after energization are the same, drives the linear motor in the first driving method in a direction such that the values output from the origin detection sensor become different. When the values output from the origin detection sensor are different, the first driving method is terminated and the linear motor is stopped. The origin setting device according to (6). (8) The control unit energizes the coil of the linear motor with the initial excitation pattern, and when the values output from the origin detection sensor before and after energization are different, terminates the first driving method and stops the linear motor. The origin setting device according to (6) or (7). (9) The control unit After terminating the first driving method, drives the linear motor in the second driving method so as to move the movable part in a direction such that the values output from the origin detection sensor become different. The origin setting device according to any one of (6) to (8). (10) The control unit While driving the linear motor in the second driving method, sets the position where the values output from the origin detection sensor are different as the origin. The origin setting device according to (9). (11) The control unit is while the linear motor is being driven by the second driving method, if the value output from the origin detection sensor is different, the second driving method is terminated and the linear motor is stopped The origin setting device according to (10). (12) The initial excitation pattern of the first driving method is set to a value with an electrical angle shifted by 90° to the movable range side where the movement of the movable part is possible from the restricting member that restricts the movement of the movable part. The origin setting device according to any one of (5) to (9). (13) The linear motor is an actuator provided in the lens unit of the imaging device. The origin setting device according to any one of (1) to (12). (14) The linear motor drives the lens of the imaging device. The origin setting device according to (13). (15) By driving the linear motor in two different driving methods, the origin of the movable part of the linear motor is set. Origin setting method.

Explanation of symbols

[0134] 1 Linear motor 3 Movable part 13 Restricting member 22 Coil 30 Linear motor system 31 Upper control unit 32 Motor drive control unit

Claims

1. A linear motor for moving a lens, a control unit that sets the origin of the movable part of the linear motor by driving the linear motor in a first driving method driven by open-loop control and then driving the linear motor in a second driving method driven by closed-loop control; comprising: in the first driving method, the coil of the linear motor is energized with a predetermined excitation pattern, in the second driving method, the coil of the linear motor is energized with an excitation pattern corresponding to the position of the movable part, the control unit sets, as an initial excitation pattern in the first driving method, an excitation pattern that is less than 180° electrically shifted from the movable range side where the movable part can move from a restricting member that restricts the movement of the movable part; a lens unit.

2. comprising an origin detection sensor that outputs different values depending on the position of the movable part with a predetermined position as a boundary, the initial excitation pattern is set for each output value of the origin detection sensor The lens unit according to claim 1.

3. the control unit energizes the coil of the linear motor with the initial excitation pattern, and if the values output from the origin detection sensor before and after energization are the same, drives the linear motor in the first driving method in a direction such that the values output from the origin detection sensor become different. If the values output from the origin detection sensor are different, the first driving method is terminated and the linear motor is stopped; The lens unit according to claim 2.

4. the control unit energizes the coil of the linear motor with the initial excitation pattern, and if the values output from the origin detection sensor before and after energization are different, the first driving method is terminated and the linear motor is stopped; The lens unit according to claim 2.

5. the control unit after terminating the first driving method, drives the linear motor in the second driving method so as to move the movable part in a direction such that the values output from the origin detection sensor become different; The lens unit according to claim 2.

6. the control unit sets, as the origin, the position where the values output from the origin detection sensor are different while driving the linear motor in the second driving method; The lens unit according to claim 5.

7. the control unit While driving the linear motor by the second driving method, if the value output from the origin detection sensor is different, the second driving method is terminated and the linear motor is stopped. The lens unit according to claim 6.

8. The initial excitation pattern of the first driving method is set to an excitation pattern in which the electrical angle is shifted by 90° to the movable range side where the movement of the movable part is possible from the restricting member that restricts the movement of the movable part. The lens unit according to claim 1.

9. After driving a linear motor that moves a lens by a first driving method that drives in open-loop control, the control unit executes an origin setting process for setting the origin of the movable part of the linear motor by driving the linear motor by a second driving method that drives in closed-loop control. The first driving method energizes the coil of the linear motor with a predetermined excitation pattern. The second driving method energizes the coil of the linear motor with an excitation pattern according to the position of the movable part. In the origin setting process, as the initial excitation pattern in the first driving method, it is set to an excitation pattern in which the electrical angle is shifted by less than 180° to the movable range side where the movement of the movable part is possible from the restricting member that restricts the movement of the movable part. A method for setting the origin of a lens unit.

Images