JP2009265285A - Rocking member apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rocking member apparatus with which a relatively high resonance frequency of an oscillation system is derived by a resonance frequency detection operation, and to provide a method of detecting the resonance frequency. <P>SOLUTION: The rocking apparatus has: an oscillation system 100 having a rocking member; a driving part 120 which drives the oscillation system; detection means 140 and 152; a driving amplitude control part 154; and a driving frequency control part 156. The detection means detects the rocking amplitude of the rocking member. The driving amplitude control part performs a feedback control of the amplitude of a driving signal. The driving frequency control part controls the frequency of the driving signal input to the driving part 120. In the resonance frequency detection operation, the feedback gain of the driving amplitude control part 154 is set at a lower value than the feedback gain at other operating states, and the driving amplitude control part controls the driving amplitude so that the detected rocking amplitude may become a target value. In this state, the driving frequency control part determines the driving frequency at which the driving amplitude becomes minimum as the resonance frequency of the oscillation system on the basis of the frequencies at the respective driving states at a plurality of driving frequencies and the controlled amplitude. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a technique of an oscillating device having an oscillating body supported so as to be able to oscillate. More specifically, the present invention relates to an oscillating device such as a resonant oscillating device, an optical deflection device using the oscillating device, a method for detecting a resonance frequency of a vibration system of the oscillating device, and the like. This optical deflecting device is suitably used for an optical apparatus such as an image forming apparatus such as a scanning display, a laser beam printer, or a digital copying machine.

In recent years, an optical scanning device that scans a light beam is used to scan the light beam by an optical disk, a laser beam printer, or the like. Further, there has been proposed an optical scanning device using an optical deflecting device in which a minimal mirror is driven to resonate using silicon micromachining technology. Such a resonant optical deflecting device can be significantly reduced in size as compared with a device using a rotating polygon mirror such as a polygon mirror. In addition, low power consumption, theoretically no tilting of the mirror surface, especially the optical deflection device made of Si single crystal manufactured by the semiconductor process has no metal fatigue and excellent durability. There are features such as.

Conventional resonance type optical deflecting devices are generally driven by fixing the drive frequency of the drive signal to a frequency near the resonance frequency. In this case, the position of the scanning beam deflected and scanned by the oscillating body of the oscillating system or the detecting means for detecting the displacement angle of the oscillating body is used to detect the time when the scanning beam reaches the predetermined scanning position or Measure the time. The time is controlled to be equal to the reference time (see Patent Document 1).

However, when the resonance frequency varies depending on the environment such as manufacturing variation and temperature, the resonance frequency of the vibration system must be detected at the start of driving. As a method for detecting the resonance frequency of the vibration system, a method is known in which the drive frequency of the drive signal is repeatedly changed, and the drive frequency having the highest efficiency among them is used as the resonance frequency (see Patent Document 2). .
JP 2005-292627 A JP 2005-241482 A

However, in a high-efficiency resonance type vibration system having an oscillating body and an elastic support portion, when the driving frequency is changed, a certain amount of time is required until the oscillating frequency of the oscillating body becomes equal to the driving frequency. Particularly in the vicinity of the resonance frequency, since the driving force is small with respect to the inertial force, the change in the oscillation frequency has a time constant, and the time required for the oscillation frequency change tends to be long. For example, when the Q value of the resonance characteristics of the vibration system is around 1000, it may take about 0.5 seconds in the vicinity of the resonance frequency.

Further, it is necessary to change the driving frequency with the required frequency accuracy. Therefore, if the initially set drive frequency is significantly different from the resonance frequency, it may be necessary to change the drive frequency many times before finding the resonance frequency. For example, if the drive frequency is changed 50 times before finding the resonance frequency, and a standby time of 0.5 seconds is provided for each change, it takes about 25 seconds to find the resonance frequency. For example, when this is used for a laser beam printer, it may affect the time required to start driving.

In view of the above problems, the oscillator device of the present invention includes an oscillation system having an oscillation body that is supported so as to be capable of oscillation, a resonance frequency, a drive unit that supplies a drive force to the oscillation system based on a drive signal, and a detection Means, a drive amplitude control unit, and a drive frequency control unit. The detection means detects at least the swing amplitude of the swing body. The drive amplitude control unit feedback controls the drive amplitude of the drive signal. The drive frequency control unit controls the drive frequency of the drive signal supplied to the drive unit. In the resonance frequency detection operation, the feedback gain of the drive amplitude control unit is set to a value lower than the feedback gain set in other operation states, and the drive amplitude control unit sets the swing amplitude detected by the detection means to the target It is assumed that the drive amplitude of the drive signal is controlled to be a value. In this state, the drive frequency control unit determines that the drive amplitude of the drive signal is the minimum based on the information including the drive frequency and the controlled drive amplitude in each drive state with the drive signals having a plurality of drive frequencies. Is obtained as the resonance frequency of the vibration system.

In view of the above problems, an optical deflecting device of the present invention includes the oscillator device, wherein the optical deflector is disposed on at least one oscillator, and deflects the light beam incident on the optical deflector. And

In view of the above problems, an optical apparatus such as an image forming apparatus according to the present invention includes the light deflecting device, and the light deflecting device deflects a light beam from a light source, and at least part of the light beam is light. It is made to enter into an irradiation target object.

In view of the above problems, the detection method of the present invention includes a vibration system having a rocking body supported so as to be rockable and having a resonance frequency, and a drive unit that supplies a driving force to the vibration system based on a drive signal. Then, the resonance frequency of the vibration system of the oscillator device that feedback-controls the drive amplitude of the drive signal is detected. In the resonance frequency detection method, in the resonance frequency detection operation, the feedback gain is set to a value lower than the feedback gain set in another operation state, and the oscillation amplitude of the oscillator driven by the drive unit is a target value. The drive amplitude of the drive signal is controlled so that In this state, the oscillator is driven by drive signals having a plurality of drive frequencies, and the drive amplitude of the drive signal is minimized based on the information including the drive frequency and the controlled drive amplitude in these drive states. Is obtained as the resonance frequency of the vibration system.

According to the present invention, in the resonance frequency detection operation, the frequency that can be regarded as the resonance frequency of the vibration system by setting the feedback gain of the drive amplitude control unit to a value lower than the feedback gain in other operation states. Can be obtained at a relatively high speed.

Embodiments of the present invention will be described below. A basic embodiment of an oscillator device according to the present invention includes an oscillation system having an oscillation body that can swing and having a resonance frequency, a drive unit that supplies a driving force to the oscillation system by a drive signal, and an oscillation of the oscillator. It has a detection means for detecting the dynamic amplitude and a drive amplitude control section. The drive amplitude control unit performs feedback control of the drive amplitude of the drive signal, and uses the amplitude of the oscillator and the target amplitude as a control deviation, and feeds back a value obtained by multiplying the control deviation by a gain to the drive unit. Furthermore, a drive frequency control unit that controls the drive frequency of the drive signal supplied to the drive unit is provided. In the oscillator device, in the resonance frequency detection operation, the feedback gain of the drive amplitude control unit is set to a value lower than the feedback gain set in another operation state such as a steady state. Then, the drive amplitude control unit controls the drive amplitude of the drive signal so that the swing amplitude detected by the detection means becomes a target value. In this state, the drive frequency control unit drives the drive signal with the minimum drive amplitude based on the information including the drive frequency and the controlled drive amplitude in each drive state with the drive signals having a plurality of drive frequencies. The frequency is acquired as the resonance frequency of the vibration system.

When there is one oscillating body of the vibration system, the vibration system has one resonance frequency, the drive signal can be generated with a signal component of one frequency, and the vibration of the oscillating body has one frequency component. Therefore, the detection means detects the swing amplitude of one swing body, the drive amplitude control unit feedback-controls one drive amplitude of the drive signal, and the drive frequency control unit controls one drive frequency of the drive signal. Good.

When there are a plurality of oscillators in the vibration system, the vibration system has a plurality of resonance frequencies, the drive signal needs to be generated with signal components having a plurality of frequencies, and the vibration of the oscillator has a plurality of frequency components. Therefore, it is necessary to control the phase difference between the signal components of the plurality of frequencies of the drive signal so that the phase difference between the plurality of frequency components included in the vibration of the oscillator has a predetermined value. At this time, the control unit changes the frequency while maintaining the integer ratio of the frequency of the plurality of signal components, and the frequency of the signal component of the drive signal corresponding to the frequency component of the vibration of the oscillator and the amplitude of the frequency component of the vibration And a plurality of drive frequencies are controlled based on the measurement result.

That is, the resonance frequency of the vibration system has an n-fold frequency that is approximately n times the fundamental frequency of the fundamental wave and the fundamental frequency of the n-fold wave (n is an integer of 2 or more). The drive frequency control unit supplies a drive signal composed of drive components having a drive frequency ratio of 1 to n corresponding to the fundamental wave and the n-th harmonic to the drive unit to drive the vibration system to detect The means detects the swing amplitude of the swing component corresponding to the fundamental wave or the n-th harmonic wave of the swing body of the vibration system. The drive amplitude control unit feedback-controls the drive amplitude of the drive component corresponding to the fundamental wave or the nth harmonic wave of the drive signal. In the resonance frequency detection operation, the feedback gain to the drive amplitude of the drive component corresponding to the fundamental wave and the nth harmonic wave of the drive amplitude control unit is set to a value lower than the feedback gain set in the other operation states, respectively. . Then, the drive amplitude control unit is configured to drive the fundamental wave or the nth harmonic wave of the drive signal so that the oscillation amplitude of the oscillation component corresponding to the detected fundamental wave or the nth harmonic wave of the oscillator is a target value. It is assumed that the drive amplitude of the drive component corresponding to is controlled. In this state, the drive frequency control unit is information including the drive frequency and the controlled drive amplitude in each drive state in the drive signal of the drive frequency of the drive component corresponding to the plurality of fundamental waves or n-th harmonic wave. Based on the above, the resonance frequency of the fundamental wave or n-th harmonic wave of the vibration system is acquired. That is, the drive frequency that minimizes the drive amplitude of the drive component corresponding to the fundamental wave or the nth harmonic wave of the drive signal is acquired as the resonance frequency of the fundamental wave or the nth harmonic wave of the vibration system.

Typically, the drive frequency control unit supplies a drive signal having a drive frequency determined based on the resonance frequency of the vibration system to the drive unit in a steady operation state. The feedback gain in the resonance frequency detection operation can be stored in advance in the storage means.

In addition, the basic embodiment of the detection method according to the present invention includes a vibration system having a rocking body supported so as to be rockable and having a resonance frequency, and a drive unit that supplies a driving force to the vibration system using a drive signal. Then, the resonance frequency of the vibration system of the oscillator device that feedback-controls the drive amplitude of the drive signal is detected. In the resonance frequency detection method, in the resonance frequency detection operation, the feedback gain is set to a value lower than the feedback gain set in another operation state. Then, the drive amplitude of the drive signal is controlled so that the swing amplitude of the swing body driven by the drive unit becomes a target value. In this state, the oscillator is driven by drive signals having a plurality of drive frequencies, and the drive signal having the minimum drive amplitude is driven based on the information including the drive frequency and the controlled drive amplitude in these drive states. The frequency is acquired as the resonance frequency of the vibration system.

In this manner, in the resonance frequency detection operation, the resonance frequency can be obtained by measuring the amplitude of the drive signal performed every time the drive frequency is changed in a short time, and the time until the resonance frequency is obtained can be obtained. Can be shortened.

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

(Example 1)
FIG. 1 and FIG. 2 show a configuration diagram of Embodiment 1 in which the oscillator device of the present invention is applied to an optical deflection device. FIG. 1 shows details of the control unit 150, and FIG. 2 shows an optical deflection unit (optical scanner) of the optical deflection apparatus. In this embodiment, the light deflection unit includes a vibration system 100 including one oscillator 200 and a torsion spring 212 that is an elastic support unit, and a support unit 211 that supports the vibration system 100. The driving unit 120 that is a driving unit that applies a driving force to the vibration system 100 is configured to receive a driving signal and supply the driving force to the vibration system 100 by an electromagnetic method, an electrostatic method, a piezoelectric method, or the like. In the case of electromagnetic driving, for example, a permanent magnet may be provided on the oscillating body, and a coil for applying a magnetic field to the permanent magnet may be arranged in the vicinity of the oscillating body, or the permanent magnet and the coil may be arranged oppositely. Good. In the case of electrostatic driving, an electrode is formed on the oscillating body, and an electrode that applies an electrostatic force to the electrode is formed in the vicinity of the oscillating body. In the case of piezoelectric driving, a piezoelectric element is provided on a vibration system or a fixed support portion of the vibration system and a driving force is applied. Further, a control unit 150 that is a control unit that controls the drive unit 120 is provided.

The oscillating body 200 has a light deflection element such as a reflection mirror 230 on the surface, and scans by reflecting and deflecting the light beam 132 from the light source 131. Thus, the light deflecting element is arranged on the oscillator, and an optical deflecting device for deflecting the light beam incident on the light deflecting element is configured. Further, a light receiving element 140 constituting a detecting means is arranged, and the light receiving element 140 detects the timing at which the scanning light 133 passes through the light receiving element 140. The control unit 150 generates a drive signal based on the time that the scanning light 133 passes through the light receiving element 140 and supplies the drive signal to the drive unit 120.

FIG. 3 shows the deflection angle of the scanning light 133 by the reflection mirror 230 of the oscillator 200 of the optical deflection apparatus. The light receiving element 140 is disposed at a position where the scanning light 133 having a deflection angle smaller than the maximum deflection angle θamp of the optical scanner can be received (position of the installation angle θBD from the scanning center). In FIG. 3, the light receiving element 140 is arranged on the scanning locus of the optical scanner, but the light receiving element may be arranged in the optical path of the scanning light further deflected by a reflection mirror or the like provided separately. FIG. 4 shows time t1 and t2 related to the time change of the deflection angle θ of the scanning light 133 by the optical scanner and the time when the scanning light 133 passes through the installation angle θBD of the installation position of the light receiving element 140. For example, if the oscillating body 200 is oscillating with an amplitude θamp, the scanning light 133 passes through the light receiving element 140 twice in one oscillation period of the oscillating body. The determination method of t1 and t2 is determined as t1 when the detection time is equal to or less than a half cycle of the drive signal, and t2 as the other. That is, a period with a short interval is t1, and a period with a long interval is t2. The time change of the deflection angle θ of the scanning light 133 corresponds to the oscillating motion in which the oscillating body 200 is oscillating at a certain oscillating frequency.

A detailed configuration and operation of the control unit 150 will be described.
The time measuring unit 152 constituting the detecting unit takes in the output signal of the light receiving element 140 and measures the times t1 and t2 related to the detection time of the scanning light 133. In the control unit 150, the controller 151 sets a target time 153 to control the oscillator 200 to a target vibration displacement. The drive amplitude control unit 154 multiplies the difference between the target time 153 and the detection time by a feedback gain, and adds the result to the drive command value 159. The added value is multiplied by the signal output from the waveform generator 157, and the signal is output to the drive unit 120. The waveform generator 157 generates a waveform having a frequency set by the drive frequency control unit 156.

The drive phase detection unit 155 detects the drive phase φ of the oscillator 200 based on the detection times t1 and t2 output from the time measurement unit 152 and the waveform output from the waveform generator 157. The drive phase φ is the phase of the oscillating motion of the oscillator 200 with respect to the phase of the drive signal. As will be described later, when the drive frequency is smaller than the resonance frequency, the drive phase φ is smaller than the drive phase φ ₀ when the drive frequency is the resonance frequency f ₀ (the phase delay of the vibration motion is small), and the drive frequency is greater than the resonant frequency, the drive phase is greater than phi _0. Here, since it is only necessary to determine the amplitude of the drive signal and the drive phase φ based on the output of the time measuring unit 152, the detection means may be configured to measure the detection times t1 and t2 by providing one light receiving element 140.

The drive information recording unit 158 sets the amplitude of the drive signal controlled by the drive amplitude control unit 154 so that the oscillator 200 of the vibration system 100 has a target amplitude, and the drive frequency control unit 156 sets the waveform generator 157. Record the drive frequency fd. In this embodiment, the drive frequency control unit 156 determines the drive frequency fd based on the amplitude and drive frequency of the drive signal recorded in the drive information recording unit 158 and the drive phase φ detected by the drive phase detection unit 155. Set to the waveform generator 157. That is, the drive frequency control unit 156 determines the drive frequency of the next drive signal based on the drive phase of the oscillator with respect to the phase of the drive signal at the current drive frequency.

FIG. 5 shows an operation flow of the drive frequency control unit 156 and the drive information recording unit 158 in the present embodiment. It demonstrates along this. At the start of driving, the driving frequency control unit 156 sets the driving frequency fd ₁ based on the resonance frequency at the time of manufacture, the driving frequency at the previous driving, and the like to the waveform generator 157 and starts driving (S101). For example, the resonance frequency at the time of manufacture or the drive frequency at the previous drive may be used as it is, or may be set in consideration of the temperature at that time (generally, the resonance frequency decreases as the temperature rises). This setting may be performed automatically on the apparatus side or manually by the user. Moreover, setting the gain G ₁ at the time of feedback control of the oscillation system 100 of the oscillator device in determining the driving frequency in the present embodiment (S102).

After the start of driving (S103), it is confirmed that a signal (BD signal) enters the light receiving element 140 (S104). In this initial operation, the start drive frequency is set in the waveform generator 157 of the control unit 150, and the initial drive amplitude is set. As the start drive frequency, an average value of possible resonance frequencies, a resonance frequency at the time of the previous stop, and the like are set. The drive amplitude is set to an initial value sufficient for the scanning light 133 to enter the light receiving element 140. When the oscillating body 200 vibrates by application of a drive signal to the drive unit 120 and a signal enters the light receiving element 140, amplitude control is started (S105). That is, the drive amplitude control unit 154 controls the drive signal amplitude A _{1 so} that the oscillating body 200 of the vibration system 100 becomes the target oscillation amplitude at the drive frequency fd ₁ . The drive information recording unit 158 records the drive frequency fd ₁ and the drive signal amplitude A ₁ at this time (S106).

FIG. 6 shows the direction of drive frequency change by drive phase comparison. The drive frequency control unit 156 compares the drive phase φ ₁ detected by the drive phase detection unit 155 with the drive phase φ ₀ when driving at the resonance frequency f ₀ (this is measured and stored in advance). As a result, when the current drive phase φ ₁ is smaller than the drive phase φ _{0 at the} resonance frequency f ₀ (the oscillation phase delay is small), the following is performed. Drive frequency control unit 156 sets the drive frequency fd ₂ raising the frequency by a predetermined frequency change increment f _{the add} than the drive frequency fd ₁ to the waveform generator 157. On the other hand, when the current drive phase φ ₁ is larger than the drive phase φ _{0 at the} resonance frequency f ₀ , the drive frequency control unit 156 reduces the drive frequency by a predetermined frequency change step f _add from the drive frequency fd _1. fd ₂ is set in the waveform generator 157 (S107). At this time, similarly to the case where the drive frequency is fd ₁ , the drive information recording unit 158 uses the drive signal amplitude A _{2 and} the drive frequency so that the oscillator 200 of the vibration system 100 has a target amplitude at the drive frequency fd ₂ . fd ₂ is recorded (S108).

The frequency change increment f _add is determined in consideration of the temperature change from the previous driving, the scheduled frequency of frequency change, the required resonance frequency accuracy, and the like. For example, it is assumed that the resonance frequency has changed by about αHz considering the temperature change from the previous drive, and the drive frequency fd ₁ is set to the place where it has changed, and the frequency change is also included in the initial setting When performing three times, the frequency change increment f _add is α / 2 Hz or more. When the frequency change is scheduled to be performed twice including the first one, the frequency change increment f _add is set to α Hz or more. In other words, the frequency change increment is set so as to exceed the resonance frequency from the first set drive frequency to the last set drive frequency.

FIG. 7 and FIG. 8 show the direction of drive frequency change by comparing the drive signal amplitude. This cannot be applied when the driving frequency is changed for the first time, and the above-described driving phase comparison method may be applied for the first driving frequency change. The drive frequency control unit 156 compares the magnitudes of the drive amplitude signal A ₂ and the drive amplitude signal A ₁ recorded in the drive information recording unit 158. As a result, when A ₁ is larger than A ₂ , the drive frequency fd ₃ changed by a predetermined frequency change increment f _{add in} the same direction as the previous frequency change is set in the waveform generator 157 (drive signal in FIG. 8). (See Amplitudes A _n , A _n-1 , A _n-2 ). In the case of FIG. 8, since the drive phase is smaller than the drive phase φ _{0 at the} resonance frequency f ₀ , the drive frequencies fd _n−3 , fd _n−2 , and fd _n−1 are sequentially increased.

Conversely, as shown in FIG. 7, when A ₁ is smaller than A ₂ , in this embodiment, the drive frequency control unit 156 doubles the frequency change increment f _{add in} the direction opposite to the previous frequency change. The drive frequency fd ₃ whose frequency is changed by only this is set in the waveform generator 157 (S109). In this case, since the driving phase φ ₁ is larger than the driving phase φ _{0 at the} resonance frequency f ₀ , the driving frequency fd ₂ is lowered from the driving frequency fd _1, but the driving phase φ ₂ is lower than the driving phase φ _0. Since it is small, the driving frequency fd ₃ is increased from the driving frequency fd ₂ . Here, as in the case where the drive frequency is fd ₁ , the drive information recording unit 158 records the drive signal amplitude A ₃ such that the oscillator 200 of the vibration system 100 has a target amplitude at the drive frequency fd ₃ ( S110). In this manner, the drive frequency control unit 156 determines the drive frequency of the next drive signal based on the drive frequency and drive amplitude of the drive signal recorded in the drive information recording unit 158. More specifically, when changing the drive frequency of the drive signal, the drive frequency control unit 156 compares the drive amplitude of the drive signal of the current drive frequency with the drive amplitude of the drive signal of the previous drive frequency. The drive frequency of the next drive signal is determined.

Next, the drive frequency control unit 156 compares the drive signal amplitude recorded at the drive frequency close to the drive frequency fd ₃ out of the drive frequencies fd ₁ and fd ₂ recorded in the drive information recording unit 158 with A ₃ ( S111). As a result, when A ₃ is large, performs the driving frequency and driving amplitude is recorded in the drive information storage unit 158, wherein 1-1, wherein 1-2 below, the quadratic curve interpolation using Equation 1-3 Then, the drive frequency fd ₀ corresponding to the resonance frequency that minimizes the drive amplitude A is obtained (S114). In this way, the drive frequency fd ₀ that can be regarded as the resonance frequency can be acquired. In the following equation, “a” is a coefficient of the quadratic term of the quadratic equation passing through the three points in FIG. 7, and “b” is a coefficient of the primary term.

Next, the drive frequency control unit 156 sets the drive frequency fd ₀ in the waveform generator 157. In this way, the drive frequency control unit 156 supplies the drive signal of the drive frequency acquired as the resonance frequency of the vibration system to the drive unit 120, and drives the oscillation amplitude detected by the detection unit to be a target value. The rocking body 200 is driven by the unit 120. Intentionally, the drive frequency control unit 156 can drive the oscillator 200 by setting the drive frequency shifted from the drive frequency fd ₀ by a predetermined value in the waveform generator 157. In other words, in a steady state, which is the intended operating state of the apparatus, it may be driven at a frequency near the resonance frequency while performing feedback control, or may be driven near a frequency shifted from the resonance frequency by a predetermined value.

Conversely, if the A ₃ smaller, as the drive signal amplitude at the center frequency as shown in a portion surrounded by a broken line in FIG. 8 is smaller than the other two drive signal amplitude further changes the drive frequency The drive signal amplitude is recorded in the drive information recording unit 158. Specifically, to set the drive frequency fd _n changing the frequency by f _{the add} in the same direction as the previous drive frequency changes to the waveform generator 157 (S112). The driving information recording unit 158, the vibration system records the amplitude and comprising such a drive signal amplitude A _n of the target in the drive frequency fd _n (S113). Then, the driving frequency control unit 156 repeats the frequency changes until the drive signal amplitude A _n-1 is smaller than the driving signal amplitude A _n. Thereafter, from the drive frequencies fd _n , fd _n−1 , fd _n−2 and the drive amplitudes A _n , A _n−1 , A _n−2 recorded in the drive information recording unit 158, the above formula 1-1, formula A quadratic curve interpolation is performed from the same expressions as 1-2 and 1-3 to obtain the drive frequency fd _{0 at} which the drive amplitude is minimized. In this way, the drive frequency control unit 156 performs the next time so that the drive amplitude of the drive signal at the center drive frequency among the three consecutive different drive frequencies is smaller than the drive amplitude of the drive signal at the other drive frequency. The drive frequency of the drive signal is determined.

The present embodiment described above has the drive information recording unit 158 that records the drive frequency and amplitude of the drive signal, and the drive information recording unit has the oscillator 200 in each drive state with drive signals of a plurality of drive frequencies. Record the drive frequency and amplitude of the drive signal to be the target swing amplitude. Then, the drive frequency control unit 156 acquires the drive frequency at which the drive amplitude of the drive signal is the minimum as the resonance frequency of the vibration system 100 based on the recorded drive frequency and drive amplitude information of the plurality of drive signals.

In this embodiment, when the drive signal amplitude at the central drive frequency is not smaller than the other drive signal amplitudes among the three drive frequencies, the drive signal amplitude is measured by further changing the drive frequency in the same direction. However, this step is not necessarily performed. For example, when the position of the resonance frequency is found to where it is in the neighborhood previously performs the same quadratic curve interpolation and the putting its premise, also be determined driving frequency fd ₀ corresponding to the resonance frequency Good. Also, the rate of change of the drive signal amplitude is observed (for example, the rate of change is gradually reduced), taking into consideration it, quadratic curve interpolation similar to the above is performed, and the drive frequency fd ₀ corresponding to the resonance frequency is obtained. You may ask for.

In this embodiment, drive signal amplitudes at three drive frequencies are used, but the number is not limited to three, and drive signal amplitudes at a plurality of drive frequencies (n, n is an integer of 4 or more) are used. A negative curve interpolation may be performed. That is, here, the drive frequency control unit performs the drive frequency and the drive of the drive signal in each drive state with the drive signals of n (n is an integer of 3 or more) drive frequencies recorded in the drive information recording unit. N-1 order curve interpolation is performed from the amplitude. Then, the drive frequency that minimizes the drive amplitude of the drive signal is acquired as the resonance frequency of the vibration system.

Further, the frequency at which the amplitude of the drive signal is minimized based on the drive signal amplitude at two or more drive frequencies recorded by the drive information recording unit 158 and the parameters (Q value, etc.) of the vibration system 100 measured in advance. It can also be determined. For example, the drive signal amplitude at two or more drive frequencies may be used, and the drive frequency that minimizes the amplitude A of the drive signal may be obtained using a table created in consideration of the parameters of the vibration system 100 or some function. For example, the rate of change in drive signal amplitude is calculated from drive signal amplitudes at multiple (two or more) drive frequencies, and the amount of deviation of the minimum amplitude frequency among the multiple drive frequencies from the drive frequency with the minimum amplitude A The drive frequency with the minimum amplitude A may be obtained from the change rate table.

In addition, when the variation of the Q value, which is a parameter of the resonance characteristics of the vibration system, due to the environment is small, a obtained by Equation 1-1 can be a fixed value. From the fixed value a, the drive frequencies fd ₁ and fd ₂ and the drive signal amplitudes A ₁ and A ₂ , quadratic curve interpolation is performed using the following formula 1-4 and the above formula 1-3, which corresponds to the resonance frequency. The drive frequency fd ₀ that minimizes the amplitude A of the drive signal may be obtained. In other words, the drive frequency control unit determines the drive amplitude based on the drive frequency and drive amplitude of the drive signal in each drive state with the drive signals of two or more drive frequencies, and the characteristic parameter of the vibration system measured in advance. Is obtained as the resonance frequency of the vibration system.

Further, the drive frequency change increment f _add may be arbitrarily determined according to the accuracy in determining the drive frequency f ₀ and the fluctuation range of the resonance frequency. In this embodiment, the drive frequency change increment f _add is set to a constant value, but f _add may be changed each time the frequency is changed. For example, the change increment f _add may be changed in consideration of the change rate of the drive signal amplitude (for example, in proportion to the change rate).

In the present embodiment, the driving phase is used as a method for determining the next driving frequency fd _2. However, the driving frequency fd ₂ may be determined without using the determination based on the driving phase. For example, the next drive frequency fd ₂ may be changed in a certain direction (increase direction) by starting from a drive frequency lower than the resonance frequency whose approximate existence range is known in advance. Also, the change direction of the drive frequency may be determined in consideration of the change rate of the drive signal amplitude.

The recording of the drive signal amplitude may wait for a time from when the drive frequency is changed until the oscillator 200 actually swings at that frequency. In addition, the drive information recording unit 158 may record the average of the drive signal amplitude in a predetermined time after the change.

Further, in this embodiment, the oscillation frequency of the oscillator 200 is detected using the scanning light 133 and the light receiving element 140, but any detector that can detect the oscillation frequency such as a piezoelectric element or a piezoelectric element may be used. Good. For example, there are a method of providing a piezo sensor on the elastic support 212, a method of using a capacitance sensor, a method of using a magnetic sensor, and the like.

Next, details of the setting of the feedback gain G ₁ (S102) in the resonance frequency detecting operation. In this embodiment, the relationship between the gain G ₁ set at the start of the resonance frequency detection operation and the gain G ₂ set after setting the drive frequency fd ₀ is expressed by the following equation (2).
G ₁ <G ₂ (2)

FIG. 9 shows the drive voltage amplitude fluctuation amount of the drive signal and the displacement amplitude (oscillation amplitude) fluctuation amount of the oscillator 200 in one cycle. As long as the control loop of the drive voltage amplitude of the drive signal is stable, the gain can be made closer to the target swing amplitude as the displacement fluctuation amount of the swing body 200 becomes smaller. On the other hand, when the gain is large, the amplitude fluctuation amount of the drive voltage becomes large. For this reason, in order to obtain an accurate amplitude of the drive signal, it is necessary to perform averaging by many measurements. The multiple measurements, the time it takes to set the drive frequency fd ₀ through the resonance frequency detecting operation increases.

Conversely, when the gain is reduced, the displacement fluctuation amount of the oscillating body 200 increases, but the amplitude fluctuation amount of the drive voltage decreases, and the time required for setting the drive frequency fd ₀ can be shortened. For this reason, if the feedback gain is lowered to the allowable range of the displacement fluctuation amount of the oscillator, the time shortening effect due to the gain reduction is maximized. In the present embodiment, based on such a principle, the gain G ₁ in the resonance frequency detection operation is set as in the equation (2).

According to the present embodiment described above, in the resonance frequency detection operation, the feedback gain of the drive amplitude control unit is set to a value lower than the feedback gain in other operation states, so that the resonance frequency of the vibration system The frequency that can be viewed can be obtained at high speed and with high accuracy. That is, the resonance frequency can be obtained by measuring the amplitude of the drive signal every time the drive frequency is changed, and the time required to obtain the resonance frequency can be shortened. Therefore, after that, the drive frequency is set based on the acquired resonance frequency, and the time until the apparatus starts the intended steady operation can be shortened.

(Example 2)
A second embodiment in which the oscillator device of the present invention is applied to an optical deflecting device will be described with reference to FIGS. 10, 11, and 12. FIG. FIG. 10 is a block diagram of an optical deflecting unit (optical scanner) of the present optical deflecting device, and FIG. 11 is a diagram illustrating a deflection angle of the scanning light 133 by the reflection mirror 230 of the oscillator 200 of the present optical deflecting device. FIG. 12 is a diagram showing details of the control unit 150.

In the present embodiment, as shown in FIG. 10, the light deflection unit (optical scanner) includes at least a first rocking body 200, a second rocking body 201, a first torsion spring 212, and a second torsion spring 213. And a support unit 211 that supports the vibration system 100. A first torsion spring 212 as an elastic support part connects the first rocking body 200 and the second rocking body 201. The second torsion spring 213, which is an elastic support portion, is connected to the second oscillator 201 so as to have a torsion axis common to the torsion axis of the first torsion spring 212. The vibration system 100 of the present embodiment only needs to have at least two oscillating bodies and two torsion springs, and may be configured by three or more oscillating bodies and three or more torsion springs.

In the present embodiment, the first oscillator 200 has a reflection mirror 230 on the surface, and scans the light beam 132 from the light source 131. The function of the drive unit 120, the operation of the control unit 150, and the like are basically the same as in the first embodiment.

As shown in FIG. 11, the optical scanner has first and second light receiving elements 140 and 160, each of which can receive scanning light 133 having a deflection angle smaller than the maximum deflection angle Θamp of the optical scanner (installation angle θBD1). And an installation angle θBD2). Here, in FIG. 11, the first and second light receiving elements 140 and 160 are arranged in the optical path of the scanning light 133. However, the first and second light receiving elements 140 and 160 are arranged in the optical path of the scanning light further deflected by a reflection mirror provided separately. Two light receiving elements may be arranged. Here, it is necessary to obtain at least two amplitudes and phases described later of the vibration motion of the first rocking body 200 based on the output of the time measuring unit 152. Therefore, two light receiving elements are provided so that a larger number of detection times than the number of detection times obtained in the first embodiment can be measured.

In this embodiment, the vibration system 100 is driven by the first vibration motion driven by the fundamental wave that is the fundamental frequency, and by the nth harmonic wave that is a frequency that is approximately an integral multiple (here, approximately twice) of the fundamental frequency. The second vibration motion can be generated simultaneously. That is, the deflection angle θ of the scanning light of the optical deflecting device of this embodiment is as follows. The amplitude, frequency (angular frequency) and phase of the first vibration motion are A, ω ₁ and Ψ ₁ , respectively, and the amplitude, frequency (angular frequency) and phase of the second vibration motion are B, ω ₂ and Ψ ₂ , respectively. When the time when the appropriate time is the origin or the reference time is t, it can be expressed as the following equation (3). Since the vibration motion of the first rocking body 200 and the deflection angle θ of the scanning light have a one-to-one correspondence, the vibration motion of the first rocking body 200 is also expressed in the same format as this equation.
θ (t) = Asin (ω ₁ t + Ψ ₁ ) + Bsin (ω ₂ t + Ψ ₂ ) (3)

In this embodiment, the drive signal for generating the deflection angle θ of the optical deflecting device is also expressed by factors corresponding to A, ω ₁ , Ψ ₁ , B, ω ₂ , Ψ ₂ , and these common symbols are used. . If it is clear from the context whether the deflection angle θ or the driving signal, it will be omitted.

In order to realize such oscillatory motion of the first oscillator 200, the drive signal of the oscillator device having two natural vibration modes according to the present embodiment, the first oscillator 200 has two sinusoidal terms. The vibration system 100 is driven so as to have the vibration represented by the above formula. The drive signal may be any signal as long as the first oscillating body 200 has such a oscillating motion.

In this embodiment, if the drive frequency of the component corresponding to the fundamental wave of the drive signal is determined, the drive frequency of the component corresponding to the nth harmonic wave of the drive signal is automatically determined by multiplying the fundamental frequency drive frequency by n. If it is reversed, the drive frequency of the component corresponding to the fundamental wave of the drive signal is automatically determined by multiplying the drive frequency of the nth harmonic by 1 / n. In this specification, the approximate integer multiple is 0.98N ≦ f ₂ / f ₁ ≦ 1.02N (N is an integer of 2 or more, where f ₁ is the fundamental frequency and f ₂ is the frequency of the nth harmonic) ) Is satisfied.

In this embodiment, the swing amplitude of the first embodiment is the swing amplitude of the first or second oscillatory motion of the first oscillator 200 driven by the fundamental wave or the n-th harmonic wave (the above equation) A or B). The amplitude of the drive signal refers to the amplitude of the component corresponding to the fundamental wave or the nth harmonic wave of the drive signal. Then, the oscillation amplitude corresponding to the fundamental wave or the nth harmonic wave is detected from the detection time measured by the time measuring unit 152, and the drive signal corresponds to the fundamental frequency or the nth harmonic wave so as to be a target value. Controls the drive amplitude of the component. If the oscillation amplitude and the drive signal amplitude in the first embodiment are replaced with these amplitudes, the description of the first embodiment will explain the operation of the present embodiment. When it is desired to obtain the resonance frequency of the fundamental wave, it is replaced with that for the fundamental wave, and when it is desired to obtain the resonance frequency of the nth harmonic wave, it may be replaced with that for the nth harmonic wave. Below, the case where the resonant frequency of a fundamental wave is calculated | required is demonstrated.

In the resonance frequency detection operation for obtaining the resonance frequency of the fundamental wave, an initial operation is first performed. Here, the start drive frequency is set in the waveform generator 157 of the control unit 150, the initial drive amplitude A and Ψ ₁ are set, and the drive is performed with the drive signal of only the fundamental wave. As the start drive frequency, an average value of possible resonance frequencies, a resonance frequency at the time of the previous stop, and the like are set. A sets an initial value sufficient for the scanning light 133 to enter the light receiving elements 140 and 160. The oscillating body 200 vibrates by applying a drive signal to the drive unit 120. It waits until the oscillation amplitude of the oscillator 200 increases and a signal enters the light receiving elements 140 and 160. Subsequently, a harmonic drive signal component is applied. The control unit 150 sets the oscillation amplitude B and Ψ ₂ of the initial harmonic component. After applying the harmonic wave, the control unit 150 starts control so that the desired vibration displacement is obtained. This control is performed, for example, by calculating the operation amount of the amplitude and phase of each frequency component of the drive signal from the time difference between the detection time and the target time by calculation using a matrix. When the oscillator is controlled to converge to the desired vibration displacement, the following control operation is started.

In the present embodiment, the drive amplitude control unit 154 performs the following control based on the difference between the detection time measured by the time measurement unit 152 and the target time 153 set by the controller 151. That is, the amplitude A and the phases ψ ₁ and ψ ₂ of the component corresponding to the fundamental wave of the drive signal are controlled so that the first vibration motion of the vibration system becomes the target vibration motion. More specifically, the amplitude A is a value obtained by multiplying the difference by the feedback gain by the drive amplitude control unit 154 and adding the fundamental wave signal drive command value 159, and the fundamental drive waveform output from the waveform generator 157 Is multiplied by For the phases Ψ ₁ and Ψ ₂ , a value obtained by multiplying the difference by the gain 1102 and adding the drive command value 1104 is sent to the waveform generator 157. The waveform generator 157 outputs a waveform in accordance with the phases ψ ₁ and ψ ₂ .

Here, when obtaining the resonance frequency of the n-th harmonic wave, the amplitude B is a value obtained by multiplying the difference by the feedback gain by the drive amplitude control unit 1101 and adding the fundamental wave signal command value 1103, and from the waveform generator 157 The output is multiplied by the double wave driving waveform.

The waveform generator 157 generates the frequency set by the drive frequency control unit 156 and the waveform of the nth harmonic wave. The drive phase detection unit 155 detects the drive phase φ ₁ related to the first vibration motion of the oscillator 200 of the oscillation system 100 based on the detection time output from the time measurement unit 152 and the waveform output from the waveform generator 157. . The drive information recording unit 158 includes the amplitude of the component corresponding to the fundamental wave of the drive signal controlled by the drive amplitude control unit 154 and the drive frequency control unit 156 in the waveform generator 157 so that the vibration system has a target vibration motion. The drive frequency fd of the component corresponding to the set fundamental wave is recorded.

Based on the amplitude of the drive signal and the drive phase φ ₁ recorded in the drive information recording unit 158, the drive frequency control unit 156 determines the next drive frequency of the component corresponding to the fundamental wave and sets it in the waveform generator 157. At this time, as described above, if the drive frequency of the component corresponding to the fundamental wave is determined, the drive frequency of the component corresponding to the n-th harmonic wave is determined. The operation flow of the drive frequency control unit 156 and the drive information recording unit 158 in the present embodiment is the same as that described in the first embodiment if the above replacement is performed.

On the other hand, when the driving frequency fd ₀ of the second oscillating motion is obtained when obtaining the resonance frequency of the nth harmonic wave, the values used for the calculation are set to the driving frequencies fd ₁ , fd ₂ , and fd ₃ of the nth harmonic wave (this When the fundamental frequency is 1 / n × fd ₁ , 1 / n × fd ₂ , 1 / n × fd ₃ ). Then, by using the amplitudes B ₁ , B ₂ , and B ₃ of the components of the drive signal corresponding to the n-th harmonic wave that becomes the target vibration motion, the drive frequency fd ₀ of the n-th harmonic wave can be obtained. When determining the drive frequency fd ₀ corresponding to the resonance frequency of the second vibration motion and minimizing the amplitude B of the drive signal, when comparing the drive phase, the second vibration of the oscillator 200 of the oscillation system 100 The driving phase φ ₂ related to the motion is used.

As described above, in the present embodiment, the vibration system includes a plurality of oscillators and a plurality of elastic support portions, and the resonance frequency is substantially equal to the fundamental frequency of the fundamental wave and the fundamental frequency of the nth harmonic wave. It has n times the frequency n times (n is an integer of 2 or more). The drive frequency control unit supplies a drive signal having a drive frequency component having a ratio of 1 to n corresponding to the fundamental wave and the n-th harmonic to the drive unit, and causes the drive unit to drive the vibration system. The detection means detects the oscillation amplitude of the oscillation component corresponding to the fundamental wave or the nth harmonic wave of the oscillator of the vibration system, and the drive amplitude control unit detects the oscillation amplitude of the component corresponding to the fundamental wave or the nth harmonic wave of the drive signal. Control the drive amplitude. Then, the drive amplitude control unit corresponds to the fundamental wave or the nth harmonic wave of the drive signal so that the oscillation amplitude of the oscillation component corresponding to the detected fundamental wave or the nth harmonic wave of the oscillator is the target value. In a state where the drive amplitude of the component to be controlled is controlled, the drive frequency control unit operates as follows. Based on the information including the driving frequency and the controlled driving amplitude in each driving state with the driving signal of the driving frequency of the component corresponding to a plurality of fundamental waves or n-th harmonic wave, the fundamental wave or n-th harmonic wave of the vibration system Get the resonance frequency of. This is obtained as a drive frequency at which the drive amplitude of the component corresponding to the fundamental wave or n-th harmonic wave of the drive signal is minimized.

In addition, the same modification as described in the first embodiment can be used in the present embodiment. If the drive frequency of the first vibration motion and the drive frequency of the second vibration motion can be handled in the same way, the resonance frequencies of both can be detected simultaneously.

In the second embodiment described above, the same effects as in the first embodiment can be obtained.

(Example 3)
Example 3 will be described. The third embodiment uses the same optical scanner shown in FIG. 10 as the second embodiment and the control unit 150 shown in FIG. The flow from the detection of the resonance frequency to the determination of the drive frequency is substantially the same as in the first and second embodiments. The difference is in the setting of the gain G ₁ in FIG. In the case of a vibration system having two oscillators, there are two resonance frequencies, and the resonance frequency is approximately 1: 2. The ratio of the resonance frequencies may be approximately 1: n (n is an integer).

As shown in FIG. 13, the two resonance frequencies may deviate slightly from the integer ratio. When this deviation is Δf, the first resonance frequency (fundamental wave) is f ₀ 1, and the second resonance frequency (double wave) is f ₀ 2, the following equation (3) is established.
Δf = f ₀ 2−2 × f ₀ 1 (3)

In general, when controlling the amplitude of the oscillating body, when the feedback gain is the same value, the displacement fluctuation amount of the oscillating body is smaller when the drive frequency is closer to the resonance frequency. As shown in the first embodiment, when the displacement fluctuation amount of the oscillator is small, the amplitude fluctuation amount of the drive voltage is large. As described above, in order to shorten the time required to detect the resonance frequency and determine the drive frequency, it is desired to reduce the amplitude fluctuation amount of the drive voltage. However, as Δf increases, the feedback gain of either the driving fundamental wave or the harmonic wave increases. In this state, when the resonance frequency changes due to an environment such as temperature change, the feedback gain with respect to the sensitivity of the oscillator becomes relatively large, and the amplitude fluctuation amount of the drive voltage becomes large.

Therefore, in the third embodiment, the feedback gain G ₃₁ to the amplitude of the fundamental drive signal and the feedback gain G ₃₂ to the amplitude of the double-wave drive signal set during the resonance frequency detection operation take the magnitude of Δf into consideration. To set that value.

For example, let G _{01 be} the feedback gain to the drive fundamental wave when steady driving is performed after determining the drive frequency fd, and G _{02 be} the feedback gain to the drive harmonic. At this time, the respective feedback gains G ₃₁ and G ₃₂ in the resonance frequency detection operation state are set as in the following equations (4) and (5). Here, α and β are values between 0 and 1 such that G ₃₁ <G ₀₁ and G ₃₂ <G ₀₂ , respectively.
G ₃₁ = α × [(Δf + f ₀ 1) / f ₀ 1] × G ₀₁ = α × [f ₀ 2 / f ₀ 1-1] × G ₀₁ (4)
G ₃₂ = β × [(Δf + f ₀ 2) / f ₀ 2] × G ₀₂ = 2 × β × [1-f ₀ 1 / f ₀ 2] × G ₀₂ (5)

That is, in this embodiment, the feedback gain is set to a difference Δf between a value obtained by multiplying the first resonance frequency (fundamental wave) by an integer and a second resonance frequency value (double wave), or the first resonance frequency value. It is set based on the ratio with the second resonance frequency value.

Also in this embodiment, the same effect as in the second embodiment can be obtained.

(Example 4)
Example 4 will be described. In the fourth embodiment, the same optical scanner shown in FIG. 10 as in the second embodiment and the control unit 150 shown in FIG. 12 are used. The flow up to the determination of the drive frequency is also substantially the same as in the first and second embodiments. The difference is in the setting of the gain G ₁ in FIG.

As described in the third embodiment, in the case of a vibration system having two oscillators, the two resonance frequencies may slightly deviate from the integer ratio as shown in FIG. In such a case, the situation described in Example 3 occurs.

Therefore, in the fourth embodiment, the feedback gain G ₄₁ to the amplitude of the drive signal component of the fundamental wave set during the resonance frequency detection operation is the drive basic when the drive frequency fd is set in the vicinity of the resonance frequency f ₀ 1 during steady drive. Set to feedback gain G ₄₀₁ to wave. On the other hand, the feedback gain G ₄₂ to the amplitude of the drive signal frequency doubled sets the feedback gain G ₄₀₂ to the drive frequency doubled at the time of setting the drive frequency fd in the resonance frequency f ₀ 2 vicinity during steady driving. Thereby, even if the resonance frequency shifts in a direction approaching the drive frequency due to an environment such as a temperature change, the feedback gain with respect to the sensitivity of the oscillator does not exceed the feedback gain at the time of steady driving. Therefore, the amplitude fluctuation amount of the drive voltage during the resonance frequency detection operation can be suppressed to be small.

That is, here, the first gain to the drive fundamental wave set during the resonance frequency detection operation is steady with a drive signal of a composite wave of the first resonance frequency (fundamental wave) and an integer multiple of the resonance frequency. Set to the feedback gain to the driving fundamental wave when driving. Then, the second gain to the drive harmonic is driven when the stationary drive is performed with the drive signal of the composite wave of the second resonance frequency (harmonic) and 1 / integer thereof (1 / n value). Set to feedback gain to harmonic.

Also in this embodiment, the same effect as in the second embodiment can be obtained.

(Example 5)
FIG. 14 is a diagram showing a fifth embodiment relating to an optical apparatus using the light deflection apparatus of the present invention. Here, an image forming apparatus is shown as an optical apparatus. In FIG. 14, 803 is an optical deflecting device according to the present invention, and in this embodiment, incident light is scanned one-dimensionally. Reference numeral 801 denotes a laser light source. Reference numeral 802 denotes a lens or a lens group, and reference numeral 804 denotes a writing lens or a lens group. Reference numeral 805 denotes a photosensitive member, and reference numeral 806 denotes a scanning locus.

The laser light emitted from the laser light source 801 is subjected to predetermined intensity modulation related to the light deflection / scanning timing, and is scanned one-dimensionally by the light deflector 803. The scanned laser light forms an image on the photosensitive member 805 by the writing lens 804. The photosensitive member 805 is uniformly charged by a charger (not shown), and an electrostatic latent image is formed on the portion by scanning light thereon. Next, a toner image is formed on the image portion of the electrostatic latent image by a developing device (not shown), and an image is formed on the paper by transferring and fixing the image on, for example, a paper (not shown). Since it is an image forming apparatus using the optical deflecting device of the present invention capable of quickly obtaining and driving a frequency that can be regarded as a resonance frequency with high accuracy, a high-performance image forming apparatus that can quickly start driving is provided. realizable.

The light deflecting device of the present invention can also be used for other optical devices. In these devices, the light beam from the light source is deflected and at least part of the light beam is incident on the light irradiation target. As such an optical apparatus, there is an optical apparatus that scans a light beam such as an image display apparatus or a barcode reader, in addition to an image forming apparatus such as a laser beam printer.

FIG. 3 is a block diagram showing a configuration example of Example 1 according to an optical deflecting device using the oscillator device of the present invention. 1 is a block diagram of an optical deflector according to Embodiment 1. FIG. FIG. 6 is a diagram for explaining a deflection angle of the optical deflecting device of the first embodiment. 3 is a graph showing a change with time of a deflection angle of the optical deflecting device of Example 1. FIG. 2 is a flowchart of the first embodiment. It is a figure explaining the change of the drive frequency of the drive signal by drive phase comparison. It is a figure explaining the change of the drive frequency of a drive signal by the comparison of a drive signal amplitude. It is a figure which shows three drive frequencies used for quadratic curve interpolation. It is a figure explaining a drive voltage amplitude fluctuation amount and a rocking body displacement fluctuation amount. 6 is a block diagram of an optical deflector according to Embodiments 2 to 4. FIG. FIG. 6 is a diagram for explaining a deflection angle of the optical deflecting devices of Examples 2 to 4. FIG. 6 is a block diagram showing a configuration example of Examples 2 to 4 related to an optical deflecting device using the oscillator device of the present invention. It is a graph which shows the frequency-drive voltage characteristic at the time of control of the vibration system containing two rocking bodies. FIG. 10 is a diagram for explaining an embodiment 5 according to an image forming apparatus using the oscillator device of the present invention for an optical deflecting device.

Explanation of symbols

100 Vibration system
120 Drive unit
131, 801 Light source
132 Light beam
133 Scanning light
140, 160 Detection means (light receiving element)
150 Control unit
151 controller
152 Detection means (time measurement unit)
153 Target time
154, 1101, 1102 Drive amplitude controller (feedback gain)
155 Drive phase detector
156 Drive frequency controller
157 Waveform generator
158 Drive information recording unit
200, 201 Oscillator
230 Optical deflection element (mirror)
803
Optical deflection device
805 Light irradiation object (photoconductor)

Claims (9)

A vibration system having a oscillating body supported so as to be able to oscillate and having a resonance frequency;
A drive unit for supplying a driving force to the vibration system based on a drive signal;
Detection means for detecting at least a swing amplitude of the swing body;
A drive amplitude control unit that feedback controls the drive amplitude of the drive signal;
A drive frequency control unit that controls a drive frequency of a drive signal supplied to the drive unit,
In the resonance frequency detection operation, the feedback gain of the drive amplitude control unit is set to a value lower than the feedback gain set in another operation state, and the swing amplitude detected by the detection unit is detected by the drive amplitude control unit. In the state where the drive amplitude of the drive signal is controlled so that becomes the target value, the drive frequency control unit controls the drive frequency and the controlled frequency in each drive state with the drive signals of a plurality of drive frequencies. An oscillator device characterized in that, based on information including a drive amplitude, a drive frequency that minimizes the drive amplitude of the drive signal is acquired as a resonance frequency of the vibration system. The oscillator device according to claim 1,
The vibration system includes a plurality of oscillators supported so as to be capable of oscillation, and a resonance frequency thereof has a fundamental frequency of a fundamental wave and an n-fold frequency that is approximately n times the fundamental frequency of an n-fold wave (n Is an integer greater than or equal to 2),
The drive frequency control unit supplies the drive unit with a drive signal having a drive frequency with a ratio of 1 to n corresponding to the fundamental wave and the n-th harmonic wave to drive the vibration system to the drive unit. Let
The detecting means detects a swing amplitude of a swing component corresponding to the fundamental wave or the n-th harmonic wave of the swing body of the vibration system;
The drive amplitude control unit feedback-controls the drive amplitude of the drive component corresponding to the fundamental wave or the nth harmonic wave of the drive signal,
In the resonance frequency detection operation, the feedback gain to the drive amplitude of the drive component corresponding to the fundamental wave and the nth harmonic wave of the drive amplitude control unit is lower than the feedback gain set in the other operation state, respectively. And the drive amplitude control section sets the fundamental wave or the drive signal so that the oscillation amplitude of the oscillation component corresponding to the fundamental wave or the n-th harmonic wave of the detected oscillator becomes a target value. In a state where the drive amplitude of the drive component corresponding to the nth harmonic wave is controlled, the drive frequency control unit is configured to drive each of the drive signals having the drive frequency corresponding to the plurality of fundamental waves or nth harmonic wave. Based on the information including the drive frequency and the controlled drive amplitude in the drive state, the drive frequency at which the drive amplitude of the drive component corresponding to the fundamental wave or the n-th harmonic wave of the drive signal is minimized is the fundamental of the vibration system. Wave or n Oscillator device and acquires the resonance frequency of the wave. The oscillator device according to claim 1 or 2,
The drive device according to claim 1, wherein the drive frequency controller supplies a drive signal having a drive frequency determined based on a resonance frequency of the vibration system to the drive unit in a steady operation state. The oscillator device according to any one of claims 1 to 3,
Having storage means;
An oscillator device, wherein a feedback gain in the resonance frequency detection operation is stored in the storage means in advance. The oscillator device according to claim 2,
The feedback gain in the resonance frequency detection operation is the difference between the value obtained by multiplying the fundamental frequency of the fundamental wave by n and the n-fold frequency of the n-fold wave, or the fundamental frequency of the fundamental wave and the n-fold frequency of the n-fold wave. The oscillator device is set based on a ratio of The oscillator device according to claim 2,
The feedback gain to the drive amplitude of the drive component corresponding to the fundamental wave and the n-th harmonic wave of the drive amplitude control unit, respectively, the fundamental frequency of the fundamental wave and the drive component of the drive frequency of the value obtained by multiplying the fundamental frequency by n A feedback gain to a drive amplitude of a drive component of the fundamental frequency drive frequency when driven by a drive signal consisting of: a drive component of a drive frequency of the n-fold frequency and a value of 1 / n of the n-fold frequency An oscillator device characterized in that it is set to a feedback gain to a driving amplitude of a driving component of the driving frequency of the n-fold frequency when driving with a driving signal. The oscillator device according to any one of claims 1 to 6,
An optical deflecting device, wherein an optical deflecting element is disposed on at least one of the oscillators, and deflects a light beam incident on the optical deflecting element. It has an optical deflecting device according to claim 7,
An optical apparatus, wherein the light deflector deflects a light beam from a light source and causes at least a part of the light beam to enter a light irradiation target. A vibration system having a vibration body that is supported so as to be capable of rocking and having a resonance frequency and a drive unit that supplies a driving force to the vibration system based on a drive signal, and that performs feedback control on the drive amplitude of the drive signal. A method for detecting a resonance frequency of a vibration system of a moving body device,
In the resonance frequency detection operation, the feedback gain is set to a value lower than the feedback gain set in other operation states, and the oscillation is driven so that the oscillation amplitude of the oscillation body driven by the drive unit becomes a target value. In a state where the drive amplitude of the signal is controlled, the oscillator is driven with a drive signal having a plurality of drive frequencies, and the drive frequency in each drive state with the drive signals having the plurality of drive frequencies is controlled. A resonance frequency detection method comprising: obtaining a drive frequency that minimizes the drive amplitude of a drive signal as a resonance frequency of the vibration system based on information including the drive amplitude.

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