JP2010097092A - Oscillating body apparatus, deflection device using the same, and method of controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oscillating body apparatus that achieves stable drive of an oscillation system regardless of conditions such as the individual difference of an oscillation system or a drive environment, and to provide a deflection device or the like. <P>SOLUTION: In the oscillating body apparatus, a position detection means 106 detects an oscillation waveform of the oscillation system. A drive command waveform update means 102 performs feedback control of a drive command waveform data set, based on an oscillation waveform data set converted by a conversion means 107 and an ideal waveform data set stored in an ideal waveform storage means 101. A drive means 104 drives the oscillation system, based on the output of the drive command waveform update means. A frequency characteristic detection means 109 detects an amplitude ratio or a phase difference between the drive command waveform data set and the oscillation waveform data set about each component of oscillation. A control means 110 controls one of the fundamental frequency of the oscillation and the resonance frequency of the oscillation system, based on the output of the frequency characteristics detection means. The oscillation system is driven, while the frequency that maximizes a rate of change of the amplitude ratio or the phase difference in the oscillation system is not matched with each frequency of the oscillation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to an oscillating body device having an oscillating system having an oscillating body that can oscillate, a one-dimensional or two-dimensional deflection device using the oscillating body device, a control method of the oscillating body device, and the like.

2. Description of the Related Art Conventionally, a scanning projector is known as an optical device having a deflecting device that deflects light. In the above deflecting device, utilizing the fact that the laser beam traveling along the light path is easily narrowed to one small light spot, the light beam emitted from the light source is condensed on the small light spot and irradiated onto the object surface, A light spot displayed on the scanning plane is defined as one pixel. These pixels are arranged two-dimensionally by main scanning and sub-scanning in a direction substantially perpendicular to the main scanning, and the display surface of the projector is configured using the afterimage effect of the human eye.

In the projection apparatus as described above, in order to configure the display surface by arranging the light spots, the first deflection apparatus scans the light spots in the main scanning direction, and then uses the second deflection apparatus to change the main scanning line. They are sequentially arranged in the sub-scanning direction. Such a scanning method is called raster scanning. In order to perform drawing with high accuracy by raster scanning, scanning by the second deflecting device is required to have a constant drawing speed on the drawing surface, that is, high linearity of the drawing locus.

In order to satisfy such a requirement, in Patent Document 1 and Patent Document 2, the output of the sensor that detects the deflection position of the deflection device is used as the amplitude / phase information of the fundamental frequency component of the repeated deflection and its integer harmonic component. handle. Based on the obtained amplitude / phase information, a feedback operation of the drive command waveform is performed in the frequency domain, and the function generator is driven from the result to generate a drive current.
JP-A-11-231253 JP 2005-080355 A

FIG. 15 shows an example of the relationship between the amplitude ratio of the deflection waveform to the drive command waveform of the one-dimensional deflection apparatus and the frequency. The amplitude ratio is indicated by a value normalized by the amplitude ratio at the resonance frequency of the vibration system of the deflecting device. In a deflection device having resonance characteristics, the gain (amplitude ratio between the drive command waveform [corresponding to the motion command] and the deflection waveform [corresponding to the actual motion] changes significantly depending on the frequency, and is the largest near the resonance frequency. Become. In particular, it is assumed that waveform control of repetitive deflection with non-resonant driving is performed by synthesizing frequency components for a control target having characteristics as shown in FIG. In this case, the gain fluctuates greatly for each frequency component (repetitive fundamental frequency component and its integer harmonic component) used for control. As a result, in the conventional waveform control by frequency synthesis, when using a frequency component that crosses the resonance frequency of the resonance characteristics, one of the frequencies used for control coincides with the resonance frequency, resulting in an unexpectedly high gain. Can happen. If measures against such a situation are not taken, there may be a problem that a large overshoot occurs at the frequency component that matches the resonance frequency, and the convergence of the control becomes slow.

On the other hand, in a micro-electro-mechanical-systems (MEMS) scanner, it is widely known that there is a large variation in resonance frequency for each individual. Also, the resonance frequency of the MEMS scanner is likely to change due to changes over time and environmental changes.

However, in Patent Document 1 and Patent Document 2, no consideration is given to the resonance characteristics of the deflecting device. Therefore, in order to cope with the resonance characteristics determined by various conditions as described above, it is generally necessary to set the feedback gain of the controller small.

In view of the above problems, an oscillator device having an oscillation system including an oscillator according to the present invention includes a clock generation means, an oscillation system, a position detection means, a conversion means, an ideal waveform storage means, and a drive command waveform update means. And a function generation means, a drive means, a frequency characteristic detection means, and a control means. The vibration system includes a rocking body that repeatedly vibrates in synchronization with the output of the clock generation means. The position detecting means detects a vibration waveform of the oscillator of the vibration system. The converting means converts the output of the position detecting means into a vibration waveform data set composed of the fundamental frequency component of the repeated vibration and the amplitude and phase of the integer harmonic component thereof. The ideal waveform storage means stores an ideal waveform data set composed of ideal amplitude and phase values targeted for the vibration waveform with respect to the fundamental frequency component of repetitive vibration and its integer harmonic components. The drive command waveform update means is composed of the amplitude and phase of the drive command waveform to the vibration system with respect to the fundamental frequency component of the repeated vibration and its integer harmonic component based on the vibration waveform data set and the ideal waveform data set. Feedback control is performed on the drive command waveform data set. The function generator generates a vibration system drive command signal based on the output of the drive command waveform update unit. The driving means drives the vibration system based on the output of the function generating means. The frequency characteristic detecting means detects the amplitude ratio or phase difference between the drive command waveform data set and the vibration waveform data set for the fundamental frequency component of repetitive vibration and its integer harmonic component. The control means controls one of the fundamental frequency of repetitive vibration and the resonance frequency of the vibration system based on the output of the frequency characteristic detection means. Then, the vibration system is driven in a state where the frequency at which the change rate of the amplitude ratio or the phase difference is maximum in the vibration system does not match the fundamental frequency of the repeated vibration and the integer harmonic frequency thereof.

In view of the above problems, the deflection device of the present invention includes the oscillator device, and the oscillator of the oscillation system includes an optical deflection element for deflecting incident light.

In view of the above problems, the two-dimensional deflection apparatus of the present invention deflects incident light in a second direction substantially perpendicular to the first direction and a first deflection apparatus for deflecting incident light in the first direction. A second deflection device which is the deflection device for. The second deflecting device is configured to operate in synchronization with the first deflecting device.

Moreover, in view of the said subject, the control method of the oscillator device of this invention includes the following process.
A conversion step of converting a vibration waveform of a vibrating body of a vibration system that repeatedly vibrates in synchronization with a clock into a vibration waveform data set composed of the amplitude and phase of the fundamental frequency component of the repeated vibration and its integer harmonic component.
A comparison step of comparing an ideal waveform data set composed of ideal amplitude and phase values of the vibration waveform with respect to the fundamental frequency component of the repetitive vibration and its integer harmonic component with the vibration waveform data set.
A feedback control step of feedback-controlling a drive command waveform data set composed of the amplitude and phase of the drive command waveform for the vibration system with respect to the fundamental frequency component of repeated vibration and its integer harmonic component based on the result of the comparing step.
A driving process for driving the vibration system based on the drive command waveform data set.
A detection step of detecting an amplitude ratio or phase difference between the drive command waveform data set and the vibration waveform data set with respect to the fundamental frequency component of the repeated vibration and its integer harmonic component.
Based on the detected amplitude ratio or phase difference, the frequency at which the change rate of the amplitude ratio or phase difference is maximum in the vibration system does not match the fundamental frequency of the repeated vibration and its integer harmonic frequency. A control process for controlling at least one of the fundamental frequency and the resonance frequency of the vibration system.

According to the present invention, the frequency at which the rate of change of the amplitude ratio or phase difference in the vibration system is maximized, the fundamental frequency of the repeated vibration or deflection, and the integer harmonic frequency thereof do not coincide with each other. Control at least one of the frequency and the resonance frequency of the vibration system. Since driving conditions suitable for the control target are set in this way, the frequency with the highest gain and the frequency components used for control are independent of various conditions such as individual differences in vibration systems such as MEMS scanners and driving environments. And a stable vibration system can be realized.

Embodiments of the present invention will be described below. What is important in the present invention is the following. That is, when the gain between the drive command waveform and the vibration waveform varies greatly within the range of the frequency component used to form the drive command waveform, it is possible to appropriately select at least one of the fundamental frequency and the resonance frequency of the repeated vibration. This means that the variation in frequency characteristics can be absorbed. In the present invention, paying attention to this point, the gain or phase difference is detected for each frequency component used for control, and the frequency at which the gain is maximized is estimated from the result. Then, a drive correction value is calculated such that the frequency at which the gain is maximized, the fundamental frequency of the repetitive vibration, and its integer harmonic frequency do not match, and the drive condition is set using this. By setting the driving conditions suitable for the controlled object in this way, the frequency at which the gain is maximized and the fundamental frequency of repeated deflection are independent of the individual differences of the oscillator device such as the MEMS scanner and the driving environment. And their integer harmonics can be prevented from matching. Here, when estimating the frequency at which the gain is maximized, the gain itself may be detected and estimated, or the phase difference may be detected and estimated from the change rate of the phase difference. This is because the change rate of the phase difference is maximized where the gain is maximized.

Based on the above concept, the basic embodiment of the oscillator device of the present invention includes the above-described clock generation means, vibration system, position detection means, conversion means, ideal waveform storage means, and drive command waveform update. Means, function generation means, drive means, frequency characteristic detection means, and control means. A basic embodiment of the deflecting device includes this oscillator device, and the oscillator of the oscillation system includes an optical deflection element for deflecting incident light. Further, the basic embodiment of the two-dimensional deflecting device includes a first deflecting device for deflecting incident light in the first direction and a deflecting device for deflecting incident light in a second direction substantially orthogonal to the first direction. A second deflection device which is the deflection device; The second deflecting device is configured to operate in synchronization with the first deflecting device.

Further, the basic embodiment of the control method of the oscillator device of the present invention includes the conversion step, the comparison step, the feedback control step, the driving step, the detection step, and the control step described above.

On the basis of the basic configuration, the following configuration can also be adopted. The control means can be configured to be connected to the clock generation means in order to control the clock cycle (see the example of FIG. 2 described later). In this case, an ideal waveform generation unit that reconfigures an ideal waveform according to the cycle of a signal generated by the clock generation unit can be provided, and the control unit can be configured to be connected to the ideal waveform generation unit (described later). (See the example in FIG. 11). In addition, a frequency characteristic adjusting means for adjusting the resonance frequency of the vibration system can be provided, and the control means can be configured to be connected to the frequency characteristic adjusting means (see the example of FIG. 6 described later). .

In the two-dimensional deflection apparatus, the control unit is connected to a drive cycle generation unit for controlling a deflection cycle of the first deflection unit, and the drive cycle generation unit sets an output cycle of the clock generation unit. It can be configured to be connected to clock generation means for control. This is shown in the example of FIG. 13 described later. The first deflecting device may include a frequency characteristic adjusting unit, and the control unit may be connected to the frequency characteristic adjusting unit in order to control the resonance frequency of the first deflecting device (described later). (See the example in FIG. 14).

In the control method of the oscillator device, the control step may include the following steps (see an example of FIG. 3A described later). That is, a step of estimating the frequency at which the change rate of the amplitude ratio or phase difference is the largest. A step of selecting two consecutive order frequency components in the vicinity of the frequency giving the maximum rate of change of the amplitude ratio or phase difference from the fundamental frequency component of the repetitive vibration and its integer harmonic component. Calculating a correction value of the fundamental frequency of the repetitive vibration or the resonance frequency of the vibration system so that the change rate of the amplitude ratio or the phase difference between the two consecutive order frequency components coincides.

Further, in the control method of the oscillator device, the control step may include the following steps (see an example of FIG. 3B described later). That is, a step of selecting a set of frequency components composed of two frequency components from the fundamental frequency component of the repetitive vibration for estimating the frequency at which the change rate of the amplitude ratio or the phase difference is maximized and the integer harmonic components thereof. Calculating a correction value of the fundamental frequency of the repetitive vibration or the resonance frequency of the vibration system so that the B / A value matches a predetermined value determined from the set of frequency components for the selected set of frequency components; Here, the change rate of the amplitude ratio or phase difference in one frequency component is A, and the change rate of the amplitude ratio or phase difference in the other frequency is B. In this case, the control step selects a plurality of sets of frequency components, calculates a correction value for each of the plurality of sets, and the basic frequency of repetitive vibration or resonance of the vibration system from the correction values obtained for the plurality of sets. A step of determining a frequency correction value may be included.

In the control method for the oscillator device, the control step may include a step of manipulating the output frequency of the clock generation means for generating the clock based on a correction value of the fundamental frequency of repetitive vibration. In this case, the control step may include a step of setting a frequency generated by the clock generation unit and a step of reconfiguring the ideal waveform data set according to a cycle of a signal generated by the clock generation unit. (See the example of FIG. 11 described later). Further, the control step may include a step of manipulating the resonance frequency of the vibration system based on the correction value of the resonance frequency of the vibration system (see the example of FIG. 6 described later).

A preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a preferred embodiment of the present invention. This deflection apparatus using the oscillator device includes an ideal (target) waveform storage means 101, a drive waveform update means 102, a function generator 103, a driver 104, a deflector 105, a sensor unit 106, a Fourier transformer 107, a clock in the frequency domain. The generation circuit 108 is configured. In addition to these, a frequency characteristic detection means 109 and a control unit 110 as control means are provided. The function generator 103 is function generating means for outputting a drive command signal, the driver 104 is drive means, the sensor unit 106 is position detection means, the Fourier transformer 107 is conversion means, and the clock generation circuit 108 is Clock generation means. The drive waveform update unit 102 that is a drive command waveform update unit includes an adder 1021, a divider 1022, an adder 1023, and a drive command waveform storage unit 1024.

This deflection apparatus calculates the amplitude and phase of the fundamental frequency component of the repeated deflection and the integer harmonic component thereof for the deflection waveform that is the driving result of the deflector 105 including the vibration system, and provides one cycle of the drive position command value. The drive command waveform representing the change in the frequency is feedback controlled in the frequency domain.

This feedback control will be described in detail. The clock generation circuit 108 generates a signal having a constant period, and defines a repetition period of deflection of the deflector 105. In this deflection apparatus, the deflector 105 is driven according to the cycle of the clock generation circuit 108. The drive command waveform storage means 1024 stores the amplitude and phase of the drive command waveform for one cycle for the fundamental frequency component of repetitive deflection and its integer harmonic component. This is called a drive command waveform data set. The function generator 103 generates a position command waveform obtained by superimposing all the drive position command waveforms stored in the storage device 1024, and sends it to the driver 104. The driver 104 converts the signal from the function generator 103 into a driving current for the deflector 105. The deflector 105 is driven by this driving current, and this movement is acquired by the sensor unit 106 as a deflection position.

A deflection waveform (time change data of the deflection position) acquired by the sensor unit 106 is collected for one period of the fundamental frequency of the repeated deflection, and the fundamental frequency component of the repeated deflection and its integer order harmonic component by the Fourier transformer 107. Is converted into amplitude and phase information. The information on the amplitude and phase of each frequency component obtained here is called a deflection or vibration waveform data set.

On the other hand, the ideal waveform storage means 101 stores a set of coefficients for each frequency component of the amplitude and phase of the target ideal deflection waveform. This is called an ideal waveform data set.

The deflection waveform data set is input to the drive waveform update unit 102 together with the ideal waveform data set, and the amplitude and phase of each frequency component included in the drive command waveform data set are corrected. As a result, a new drive command waveform is generated. By repeating this series of procedures, the drive command waveform is formed in a shape that can drive the deflector 105 with the ideal waveform stored in the ideal waveform storage means 101.

The present invention relates to a method for setting drive conditions in a repetitive vibration or deflection apparatus as shown in FIG. In order to set drive conditions, the present embodiment includes a frequency characteristic detection unit 109 in a repetitive deflection deflector that feedback-controls a drive command waveform in the frequency domain. Then, based on the output, a correction value is calculated according to a driving condition such that the frequency at which the gain is maximized, the fundamental frequency of repetitive deflection, and the integer harmonic frequency thereof are not matched, and driving is performed using the correction value. A control unit 110 for setting conditions is provided.

The frequency characteristic detection means 109 is a drive command waveform data set composed of the amplitude and phase of the fundamental frequency component of the drive command waveform and its integer harmonic component, and the fundamental frequency component of the deflection waveform and the amplitude of the integer harmonic thereof. And a deflection waveform data set composed of and phase. Then, by comparing these, the gain or phase difference (the phase difference between the drive command waveform and the deflection waveform of each frequency component) of the fundamental frequency component of the repeated deflection and the integer harmonic component thereof is calculated. The control unit 110 uses the gain or phase difference calculated by the frequency characteristic detection means 109 to match the frequency at which the rate of change of the gain or phase difference is maximum with the fundamental frequency of repeated deflection and its integer harmonic frequency. The correction value of the driving condition that is not allowed is calculated. More specifically, a correction value related to a driving condition that reduces the maximum value of the gain of the fundamental frequency component of the repeated deflection and its integer harmonic component until a specific condition is satisfied is calculated.

In the present invention, in order not to make the frequency with the highest gain coincide with the frequency component used for control, at least one of the fundamental frequency of repetitive vibration or deflection and the resonance frequency of the oscillator device is operated. Embodiments of the present invention will be described below with reference to the drawings.

In the following description, fv0 represents the fundamental frequency of repeated deflection, and n represents the fundamental frequency of repeated deflection and the order of its integer harmonics. Further, it is assumed that up to the Nth (for example, 20th) harmonic of the fundamental frequency of repeated deflection is used for waveform formation. Further, the vibration system of the deflector includes, for example, one oscillating body having a mirror, and the resonance frequency of the natural vibration mode is one.

When the resonance frequency of the vibration system is 2 or more, for example, a correction value is calculated for a plurality of sets of frequency components sandwiching the resonance frequency, and the average is used as a final correction value, or the largest correction value is finally determined. It may be used as a correct correction value.

Example 1
In the first embodiment, the frequency at which the gain is highest (resonance frequency) is not matched with the frequency component used for control. For this purpose, in this embodiment, a correction value for the fundamental frequency of repeated deflection is calculated, and driving conditions are corrected by the fundamental frequency of repeated deflection.

FIG. 2 shows the system configuration of this embodiment. This embodiment is different from the above embodiment described with reference to FIG. 1 in that the control unit 110 is connected to the clock generation circuit 108. In FIG. 2 of the present embodiment, the same reference numerals as those in FIG.

In this embodiment, the drive waveform update unit 102, the function generator 103, the frequency characteristic detection unit 109, and the control unit 110 can be realized by a calculation unit such as a microcomputer. The function generator 103 may use a microcomputer or an arbitrary waveform generator. The driver 104 is implemented by means such as a PWM circuit, although the implementation method differs depending on the form of the function generator 103. The sensor unit 106 can be realized by combining an A / D converter with a capacitance type sensor, for example.

FIG. 3A is a flowchart showing the process of calculating the correction amount of the repetition period from the fundamental frequency of the repeated deflection and the gain at the integer harmonic using the control unit 110 in this embodiment. FIGS. 4 (a) and 4 (b) are diagrams showing the fundamental frequency component of the repetitive deflection before and after the correction and the gain for the integer harmonic component thereof, respectively. The gains in FIGS. 4 (a) and 4 (b) are shown as values normalized by the gain of the resonance frequency.

In this embodiment, in order not to make the frequency with the highest gain coincide with the frequency component used for the control, first, a frequency that maximizes the gain is searched from the output of the frequency characteristic detecting means 109. Further, two consecutive order frequency components in the vicinity of the frequency that gives the maximum gain are selected from the fundamental frequency component of the repetitive deflection and the integer harmonic components thereof. Then, the repetition frequency is adjusted so that the gains in the two selected frequency components match. As a result, after the repetition frequency adjustment is completed, the fundamental frequency component of the repeated deflection and the gain of the integer harmonic component thereof have a constant (equal) relationship as shown in FIG. 4B, for example. Hereinafter, a specific procedure of this embodiment will be described based on the flowchart of FIG.

In the flowchart of FIG. 3A, in S101, the control unit 110 stops the waveform update loop in correcting the repetition period output from the clock generation circuit 108. In S102, the fundamental frequency component of the repetitive deflection acquired by the frequency characteristic detecting means 109 and the gain of its integer harmonic component {Gain (fv0), Gain (2 × fv0), Gain (3 × fv0),... From (N × fv0)}, the frequency f _{Amax at} which the gain is maximized is estimated. The gains of these frequency components are {Gain (fv0), Gain (2 × fv0), Gain (3 × fv0),..., Gain (N × fv0)}. Here, the three frequencies f1, f2, and f3 are selected from the one with the largest gain, and the frequency that maximizes the gain is searched by applying to the following equation.
f _Ama = {f1 × Gain (f1) + f2 × Gain (f2) + f3 × Gain (f3)} / {Gain (f1) + Gain (f2) + Gain (f3)}
(Formula 1)

In S103, an integer n such that n × fv0 ≦ f _Amax <(n + 1) × fv0 is obtained. In S104, using the n derived in S103, a slope amount X with respect to the gain frequency in the section of (n−1) × fv0 ≦ f ≦ n × fv0 is derived according to the following equation (see FIG. 5).

Similarly, the slope amount Y with respect to the frequency of the gain in the section of (n + 1) × fv0 ≦ f ≦ (n + 2) × fv0 is calculated according to the following equation (see FIG. 5).

In S105, the repetition frequency adjustment amount Δfv0 at which the gain ratio is 1 is calculated for the two frequency components of n × fv0 and (n + 1) × fv0 according to the following equation.

この式は、Gain(n×fv0)+Ｘ×(n×Δfv0))＝Gain((n+1)×fv0)+Ｙ((n+1)×(Δfv0))の関係式から導かれるものである。

This formula is derived from the relational expression Gain (n × fv0) + X × (n × Δfv0)) = Gain ((n + 1) × fv0) + Y ((n + 1) × (Δfv0)) It is.

In S106, as shown by the following expression, the derived Δfv0 is added to the current repetition frequency fv0 to obtain a new repetition frequency, and a new fv0 is instructed to the clock generation circuit 108.
fv0 ← fv0 + Δfv0 × G (← indicates substitution) (Formula 5)
G is an adjustment gain and is in the range of 0 <G <1. It may be set according to the Q value of the deflector 105 to be applied.

In S107, it is determined whether to repeat the operations from S102 to S106. The condition is whether or not the gain ratio is 1 in two frequency components of n × fv0 and (n + 1) × fv0. In this embodiment, the gain change with respect to the frequency is approximated using the slope of the gain curve, and the basic frequency of the repeated deflection is reset. Therefore, fv0 that satisfies the above condition is calculated by repeating this operation several times.

In S108, the drive waveform update unit 102 that has been stopped in S101 is operated again. By repeating this series of operations, the fundamental frequency of the repeated deflection can be set so as to minimize the maximum value of the fundamental frequency component of the repeated deflection and the integer harmonic component thereof. As a result, even for a control target such as a MEMS scanner in which the resonance mode is likely to occur in the vicinity of the drive frequency, the feedback gain is suitably set without considering the gain variation of each drive frequency due to individual differences, changes over time, and environmental changes. Can be set. In this way, the control performance as designed can always be obtained.

As described above, in this embodiment, the gain ratio for two frequency components near the frequency at which the gain is maximized is set to 1. As a result, the basic frequency of the repeated deflection is set so that the maximum value of the fundamental frequency component of the repeated deflection and the integer harmonic component thereof is suitably kept small without measuring the deflection device characteristics in advance. It becomes possible to do.

(Example 2)
In the first embodiment, the ratio of gains in two frequency components near the frequency with the highest gain is set to 1, but the embodiment of the present invention is not limited to this. For example, the gain ratio between two desired frequency components can be set to a value P determined from the two selected frequencies. The second embodiment has such a configuration. A flowchart in this case is shown in FIG.

In S204, any two different frequency components a × fv0 and b × fv0 (a and b are integers) are selected using n derived in S103. Further, slope amounts A and B with respect to the frequency of the gain in the vicinity of the selected frequency are derived based on the following equations.

In S205, the repetition frequency is set so that the gain ratio for the two frequency components of a × fv0 and b × fv0 is a value P (a, b) determined from two integer values a and b according to the following equation. The adjustment amount Δfv0 is calculated.

この式は、Gain(a×fv0)+Ａ(a×Δfv0)＝P×{Gain(b×fv0)+Ｂ(b×Δfv0))の関係式から導かれるものである。

This equation is derived from the relational expression Gain (a × fv0) + A (a × Δfv0) = P × {Gain (b × fv0) + B (b × Δfv0)).

Note that P (a, b) used at this time is P (a, b) under a driving condition in which the ratio of gains of two frequency components sandwiching the resonance frequency of the vibration system of the deflector 105 is 1. The value of may be measured and used in advance. A value predicted based on the Q value or the resonance frequency may be used.

In S207, it is determined whether to repeat the operations from S102 to S106. The condition is whether or not the ratio of the gains of the two selected frequencies is P. In this embodiment, since the curve indicating the relationship between the gain and the frequency is approximated by using the slope, fv0 that satisfies the condition is calculated by repeating this operation several times.

In S204 and S205 of this embodiment, the gain ratio of a set of frequency components selected from the fundamental frequency component of repetitive deflection and its integer order harmonic component is constant determined by the selected frequency. The correction amount of the repetition frequency is calculated so that the value P becomes. However, regarding the selection of the two frequencies used in this embodiment, it is desirable that a and b be as close to n as possible. This is because the gain near the resonance frequency is larger and it is easier to detect an error from the target drive state. Further, it is desirable to select a frequency that satisfies the condition of a ≦ n or n + 1 ≦ b. This is because a and b are selected across the resonance frequency, so that both frequencies can select values closer to the resonance frequency. S204 and S205 may be performed for a plurality of sets of frequency components, and one of them may be selected to obtain an output. By adopting such a configuration, even when the amplitude of a specific frequency component is 0, it is possible to obtain a driving frequency suitable for the control target. This method can also be employed in the first embodiment.

Further, the correction amount may be determined by performing the operations of S204 and S205 for a plurality of sets of frequency components and taking the average thereof. By doing in this way, the influence of noise which is superimposed only on a specific frequency component can be suppressed small. This method can also be employed in the first embodiment. Further, this method can be employed when the resonance frequency of the vibration system is 2 or more as described above.

The correction of the driving condition described in the present embodiment may be performed only at the time of starting, or may be performed at regular time intervals during the control. If it is executed only at the time of startup, it is possible to cope with individual differences of devices and changes with time. Furthermore, when it is executed at regular time intervals, it is possible to follow even when a change in the environment in which the apparatus is placed fluctuates greatly. These are the same in other embodiments.

Also in the present embodiment, the configuration in which the fundamental frequency of repetitive deflection is manipulated from the relationship between the gain and frequency detected by the frequency characteristic detecting means 109 has been described. In the present embodiment, the same effect as that of the first embodiment can be achieved.

(Example 3)
In the third embodiment, the correction value related to the resonance frequency characteristic of the deflector 105 is calculated in order to prevent the frequency that gives the maximum gain, the fundamental frequency component of repeated deflection, and the integer harmonic component thereof from matching. Execute. Further, the present invention relates to a preferable method for realizing correction of driving conditions using the resonance frequency characteristics of the deflecting device.

FIG. 6 is a diagram illustrating the configuration of the deflection apparatus according to the present embodiment. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment. In the first embodiment (see FIG. 2), the manipulated variable of the fundamental frequency of the repeated deflection is calculated from the gain of the fundamental frequency component of the repeated deflection and the integer harmonic component thereof. In this embodiment, the operation amount is as follows. . The frequency f _{Amax at} which the gain is _maximized is estimated from the gain of the fundamental frequency component of the repeated deflection and the integer harmonic component thereof, so that the following (Equation 9) is satisfied.
n × fv0 ≦ f _Amax ≦ (n + 1) × fv0 (Formula 9)
That is, the correction amount of the resonance frequency of the deflector 105 is calculated so that f _Amax is controlled to be intermediate between the frequency of the nth-order harmonic and the n + _1th- order harmonic of the repetitive deflection frequency.

For this reason, the following components differ from Example 1. The deflector 105 includes a deflection frequency characteristic adjusting unit 212, and the control unit 210 is connected to the frequency characteristic adjusting unit 212. Further, a thermal characteristic storage unit 211 for storing the characteristics of the deflector 105 is provided for the operation of the frequency characteristics.

The thermal characteristic storage unit 211 stores a movement amount T (Hz / ° C.) measured in advance according to the temperature of the resonance frequency of the deflector 105. The control unit 210 calculates the operation amount of the frequency characteristic adjusting unit 212 based on the contents of the frequency characteristic detecting unit 109 and the thermal characteristic storage unit 211 (a calculation method will be described later). The frequency characteristic adjusting means 212 can be constituted by means such as a heater or a Peltier element, for example.

FIG. 7 is a flowchart illustrating a process in which the control unit 210 determines the operation amount of the frequency characteristic adjusting unit 212 in the present embodiment. FIGS. 8A and 8B are diagrams showing the fundamental frequency components of repetitive deflection before and after correction and the gains of their integer harmonic components. Here again, the gain is shown as a value normalized by the gain of the resonance frequency.

In this embodiment, the control unit 210 moves the frequency f _Amax of the deflector to the maximum between the two adjacent frequencies of the fundamental frequency of repetitive deflection and its integer harmonics. A correction amount of the resonance frequency is calculated. Based on this correction amount, the frequency characteristic adjusting means 212 is used for correction. As a result, after the repetition frequency adjustment is completed, the gain of the fundamental frequency component of the repeated deflection and the integer harmonic component thereof has a certain relationship as shown in FIG. 8B, for example. Below, the specific procedure is demonstrated based on the flowchart of FIG.

In S301, the frequency f _{Amax at} which the gain is _maximized is estimated from the fundamental frequency of the repetitive deflection acquired by the frequency characteristic detecting means 109 and the gain of its integer harmonic. The gains of these frequency components are {Gain (fv0), Gain (2 × fv0), Gain (3 × fv0),..., Gain (N × fv0)}. Again, the three frequencies f1, f2, and f3 are selected from the one with the largest gain, and the frequency at which the gain is maximized is estimated by applying to the above (Equation 1). In S302, an integer n such that n × fv0 ≦ f _Amax <(n + 1) × fv0 is obtained.

In S303, using n derived in S302, the frequency f _{Amax at} which the gain is maximized according to the following (Equation 10), and the intermediate between the nth and n + 1th harmonics of the fundamental frequency of repeated deflection. The difference Δf with respect to the frequency (n + 0.5) fv0 is obtained.
Δf = f _Amax − (n + 0.5) fv0 (Formula 10)

In S 304, the temperature change characteristic T (Hz / ° C.) of the resonance frequency of the deflector 105 is read from the thermal characteristic storage unit 211.

In S305, the necessary temperature change ΔW is calculated according to the following equation, and the frequency characteristic adjusting unit 212 is operated.
ΔW = Δf / T (Formula 11)

In S306, the process waits until the temperature change of the deflector 105 subject to temperature change is completed. In S307, it is determined whether to repeat the operations from S301 to S306. The condition is whether or not the ratio of gain is 1 for the two selected frequency components.

By repeating the operation of the present embodiment, the frequency f _Amax at which the gain of the deflector 105 is maximized is controlled so as to be positioned between two adjacent frequency components of the frequencies used for control. With this configuration, it is possible to set the driving conditions while avoiding the influence of the discontinuity of the target waveform that occurs when switching the fundamental frequency of repeated deflection.

Alternatively, only the temperature raising / cooling of the deflector by the frequency characteristic adjusting means 212 may be defined. In this case, in S306, a wait for a fixed time is performed, and the determination loop for setting the driving condition is continuously executed until the temperature holding determination condition is satisfied. When the control loop is configured in this way, only the positive / negative temperature characteristics of the deflector 105 need be stored in the temperature characteristic storage unit 211. This eliminates the need for a temperature holding mechanism, thus simplifying the system.

When the correctable temperature is also stored in the thermal characteristic storage unit 211 and the drive condition is corrected by adjusting the resonance frequency described in this embodiment, the following may be performed. That is, when the adjustment amount exceeding the range in which the resonance frequency can be adjusted is required, the repetition frequency correction unit described in the first embodiment may be operated.

FIG. 9 shows a flowchart relating to this other technique. The difference from FIG. 7 is that there is a calculation step (S308) of the total temperature correction amount, and a determination step (S309) for determining whether or not the current temperature correction amount exceeds the maximum correctable temperature Wmax. It is a point that the fundamental frequency of deflection is repeatedly adjusted (S310) only when the value exceeds. The maximum correctable temperature Wmax is determined by the limit of the capability of the frequency characteristic adjusting unit 212, such as a current that can flow through the heater. With this configuration, both control continuity, which is a merit of the method for adjusting the resonance frequency of the deflector 105, and a wide controllable range, which is a merit of the method for adjusting the basic frequency of repeated deflection, are achieved. It becomes possible.

Also in the present embodiment, the frequency with the largest amplitude (that is, gain) may be estimated from the fundamental frequency of repeated deflection and the phase of its integer harmonic. As described above, since the rate of change of the phase difference changes the most at the frequency where the gain becomes the largest, this estimation is possible.

Example 4
The fourth embodiment relates to a two-dimensional deflection apparatus using a deflection apparatus using an oscillator device according to the present invention. In FIG. 10, the typical block diagram of the two-dimensional deflection | deviation apparatus of a present Example is shown. In the present image display device, the laser light output from the modulation light source 321 that emits the red laser deflects the light in the first direction deflecting device 315 that deflects in the first direction and the second direction substantially orthogonal to the first direction. Scanning is performed by the deflector 105 described in the above embodiment. The first direction deflecting device 315 is controlled by a first direction scanning control device 319, and the deflector 105 is controlled by a second direction scanning control device 320 connected to the first direction deflecting device 315. Thus, a scanning line is formed on the screen 322. In the image display apparatus according to the present embodiment, the deflection in the second direction is performed in synchronization with the deflection in the first direction. A two-dimensional image is displayed on the screen 322 by modulating the output of the light source 321 with gradation information generated from the image information. Here, the modulation current may be controlled for each pixel period in accordance with the modulation signal corresponding to the pixel of the image on the screen 322.

Of the two deflecting devices included in the two-dimensional deflecting device of the present embodiment, in the deflector 105 in the second direction, the time for scanning on the screen at a constant speed is defined within the repeated deflection period. This is called a constant velocity deflection period. Time other than the effective drawing period is called a blanking period. Such a waveform is called a sawtooth wave. The first deflecting device 315 repeatedly performs a predetermined number of deflections during this constant velocity deflection period, and configures a scanning region on the screen 322 in which scanning lines are arranged at equal intervals.

In such a system, when the deflection cycle is repeatedly changed for the deflector 105 in the second direction, the number of scanning lines arranged in the second direction is maintained at a specified number. Therefore, it is necessary to change the length of the blanking period while keeping the constant velocity deflection period constant. At this time, it is necessary to reconstruct the ideal waveform.

FIG. 11 shows the system configuration of this embodiment. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment. The two-dimensional deflection apparatus according to this embodiment includes a first direction deflection apparatus 315 that repeatedly performs deflection in the first direction, in addition to the deflector 105 that repeatedly performs deflection in the second direction. The first direction deflecting device 315 includes a drive cycle generation circuit 313 and performs deflection in the first direction at a cycle generated by the drive cycle generation circuit 313. The deflection position of the first direction deflection device 315 is detected by the sensor unit 316 and sent to the drive signal generation unit 314. The drive signal generation unit 314 is driven based on the deflection position information so as to maintain the deflection operation of the first direction deflection device 315 constant.

On the other hand, the clock generation circuit 308 that defines the repetition cycle of the deflector 105 in the second direction generates a second deflection clock by dividing the signal of the drive cycle generation circuit 313 by k. That is, for every k pulses output from the drive cycle generation circuit 313, the clock generation circuit 308 outputs one pulse. Furthermore, this system configuration includes an ideal waveform generation unit 317 that reconstructs an ideal waveform according to the frequency division ratio in the clock generation circuit 308.

In this embodiment, in order to maintain the length of the effective scanning period in one scan, the division ratio k of the clock generation circuit 308 is operated to adjust the fundamental frequency of repetitive deflection. At the same time, the ideal waveform generation unit 317 reconstructs the ideal waveform and rewrites the ideal waveform data set in the ideal waveform storage unit 101.

FIG. 12 shows a flowchart of the control procedure of the period of the fundamental frequency of repetitive deflection in this embodiment. Steps for performing the same operation as the control procedure for the period of the fundamental frequency of repetitive deflection in the first embodiment are given the same symbols.

In S401, an integer k satisfying the following value is calculated for fv0 after the change. At this time, the deflection frequency of the deflecting device 315 in the first direction is f _H.
k ≦ f _H / fv0 <k + 1 (Formula 12)

In S402, a drive waveform corresponding to the frequency division ratio k is calculated. The generation of the drive waveform is performed in the time domain. For example, when driving in a sawtooth shape in the second direction, an ideal waveform is generated using a known method so as to smoothly connect a blanking period after generating a signal of an area where constant speed scanning is performed. The calculated ideal waveform is Fourier-transformed and then written in the ideal waveform storage means 101.

In S403, a new frequency division ratio k is written in the clock (synchronization signal) generation circuit 308. With the configuration described above, it is possible to adjust the drive characteristics of the deflector 105 in the second direction while keeping the number of scanning lines in the first direction constant during the effective drawing period.

The first direction deflecting device 315 of the present embodiment can be configured by a polygon mirror that rotates light in a certain direction and deflects light, or a galvano scanner that performs reciprocal deflection. Further, the control unit 310 and the ideal waveform generation means 317 can be realized by a calculation means such as a microcomputer. Further, the driving cycle generation circuit 313 can be realized by an oscillator, and the clock generation circuit 308 can be realized by a frequency divider.

(Example 5)
The fifth embodiment relates to another method for realizing a two-dimensional deflection apparatus using the oscillator device of the present invention. In the fourth embodiment, in order to repeatedly operate the fundamental frequency of deflection by the deflector 105 in the second direction, the clock generation circuit 308 operates the division ratio, and the ideal waveform generation unit 317 performs reconstruction of the ideal waveform. The configuration is to be performed. On the other hand, in the present embodiment, the configuration is such that the fundamental frequency of the repeated deflection of the deflector 105 is indirectly operated by operating the drive cycle of the deflecting device 315 in the first direction. And different.

FIG. 13 shows a partial configuration of the two-dimensional deflection apparatus according to the present embodiment. The control unit 410 operates the drive cycle generation unit 413 to generate a repetitive deflection cycle in the second direction that satisfies the following (Equation 13). fv0 is a fundamental frequency of repeated deflection in the deflector 105 calculated by the control unit 410, and k is a frequency division ratio of the fundamental frequency of repeated deflection in the second direction to the driving frequency in the first direction.
f _H = fv0 × k (Formula 13)

By changing the output frequency of the drive cycle generation unit 413, the fundamental frequency of the repeated deflection in the second direction generated by the clock generation circuit 308 is also changed at the same time.

Even with this configuration, in the two-dimensional deflection apparatus, it is possible to change the driving conditions while maintaining the number of first-direction scans included in the effective drawing period of the second-direction deflector 105.

FIG. 14 shows another configuration according to the present embodiment. In the present embodiment, a method of operating the frequency of the second direction deflector 105 by operating the driving cycle of the first direction deflecting device 315 is described, but the other configuration is controlled as follows.

The two-dimensional deflection apparatus includes a first direction deflection apparatus 515 that is driven to resonate. Then, by collecting the drive data by the sensor unit 316, the drive cycle generation unit 513 is controlled by the drive cycle correction unit 517 so that the first direction deflecting device 515 maintains the resonance state. In such a system, when the temperature of the first direction deflecting device 515 is controlled by the frequency characteristic adjusting means 518, the resonance frequency of the first direction deflecting device 515 changes, and the output frequency of the drive cycle generating unit 513 is changed accordingly. be changed.

With this configuration, it is possible to adjust the fundamental frequency of the repeated deflection of the second direction deflector 105 and set the driving conditions without destroying the resonance driving state of the first direction deflecting device 515.

The block diagram which shows embodiment of the deflection | deviation apparatus using the oscillator device of this invention. 1 is a block diagram showing a system configuration of a deflection apparatus according to Embodiment 1 of the present invention. (a) is a flowchart 1 for calculating a correction value of a repetition frequency in the first embodiment, and (b) is a flowchart 2 for calculating a correction value of a repetition frequency in the deflecting device according to the second embodiment. FIG. 5A is a diagram showing a normalized gain for each frequency component before adjusting the fundamental frequency of repeated deflection, and FIG. 5B is a diagram showing a normalized gain for each frequency component after adjusting the fundamental frequency of repeated deflection. The figure explaining calculation of the frequency where a gain becomes the maximum. FIG. 6 is a block diagram illustrating a configuration of a deflecting device according to a third embodiment of the invention. 9 is a flowchart 3A for calculating a resonance frequency correction value according to the third embodiment. (a) is a figure which shows the normalization gain for every frequency component before resonance frequency adjustment, (b) is a figure which shows the normalization gain for every frequency component after resonance frequency adjustment. 9 is a flowchart 3B related to calculation of a correction value of a resonance frequency in the third embodiment. The perspective view which shows the system configuration | structure of the two-dimensional deflection | deviation apparatus which concerns on Example 4 of this invention. FIG. 9 is a block diagram showing a system configuration of Embodiment 4. 10 is a flowchart 4 for controlling the period of the fundamental frequency of repetitive deflection according to the fourth embodiment. FIG. 9 is a block diagram showing a configuration of a two-dimensional deflection apparatus according to Embodiment 5 of the present invention. The block diagram which shows the structure of the two-dimensional deflection | deviation apparatus which concerns on another structure of Example 5 of this invention. The figure which shows the amplitude ratio of the deflection waveform with respect to the drive frequency of a MEMS scanner.

Explanation of symbols

101 Ideal waveform storage means 102 Drive command waveform update means (drive waveform update means)
103 Function generation means (function generator)
104 Driving means (driver)
105 Deflector (second direction deflector)
106 Position detection means (sensor unit)
107 Conversion means (Fourier transformer)
108, 308 Clock generation means (clock generation circuit)
109 Frequency characteristic detection means 110, 210, 310, 410, 510 Control means (control unit)
212, 518 Frequency characteristic adjustment means 313, 413, 513 Drive cycle generation circuit 314 Drive signal generation section 315, 515 First direction deflection device 317 Ideal waveform generation section (ideal waveform generation means)

Claims (10)

Clock generating means for generating a clock;
A vibration system including a rocking body that repeatedly vibrates in synchronization with the output of the clock generation means;
Position detecting means for detecting a vibration waveform of the oscillator of the vibration system;
Conversion means for converting the output of the position detection means into a vibration waveform data set composed of the amplitude and phase of the fundamental frequency component of the repeated vibration and its integer harmonic component;
Ideal waveform storage means for storing an ideal waveform data set composed of ideal amplitude and phase values of the vibration waveform for the fundamental frequency component of repetitive vibration and its integer harmonic components;
Based on the vibration waveform data set and the ideal waveform data set, drive command waveform data composed of the amplitude and phase of the drive command waveform for the vibration system with respect to the fundamental frequency component of repetitive vibration and its integer harmonic component Drive command waveform update means for feedback control of the set;
Function generating means for generating a drive command signal of the vibration system based on an output of the drive command waveform updating means;
Driving means for driving the vibration system based on the output of the function generating means;
A frequency characteristic detecting means for detecting an amplitude ratio or phase difference between the drive command waveform data set and the vibration waveform data set for a fundamental frequency component of repetitive vibration and an integer harmonic component thereof;
Based on the output of the frequency characteristic detection means, one of the fundamental frequency of repetitive vibration and the resonance frequency of the vibration system is controlled, and the change rate of the amplitude ratio or the phase difference is maximized in the vibration system. Control means for driving the vibration system in a state where the frequency and the fundamental frequency of the repetitive vibration and its integer harmonic frequency do not match,
An oscillator device comprising: The oscillator device according to claim 1,
The deflecting device, wherein the oscillator of the oscillation system includes an optical deflection element for deflecting incident light. 3. A second deflecting device according to claim 2, wherein the first deflecting device deflects incident light in a first direction and the deflecting device according to claim 2 for deflecting incident light in a second direction substantially orthogonal to the first direction. Including a device,
The two-dimensional deflection apparatus, wherein the second deflection apparatus operates in synchronization with the first deflection apparatus. The control means is connected to the clock generation means and an ideal waveform generation means for reconstructing an ideal waveform according to the period of the clock generated by the clock generation means, and the control means operates the clock generation means, 4. The two-dimensional changing device according to claim 3, wherein the ideal waveform generation means is connected to the ideal waveform storage means and rewrites the ideal waveform data set. The control means is connected to a drive cycle generator for controlling the deflection cycle of the first deflecting device, and the drive cycle generator is used for controlling the output cycle of the clock generator. The two-dimensional deflection apparatus according to claim 3, wherein the two-dimensional deflection apparatus is connected to the two-dimensional deflection apparatus. The first deflection apparatus includes a frequency characteristic adjusting unit, and the control unit is connected to the frequency characteristic adjusting unit to control a resonance frequency of the first deflection apparatus. The two-dimensional deflection apparatus according to 3, 4 or 5. Convert the vibration waveform of the oscillator of the vibration system that repeatedly vibrates in synchronization with the clock into a vibration waveform data set composed of the amplitude and phase of the fundamental frequency component of the repeated vibration and its integer harmonic component,
An ideal waveform data set composed of ideal amplitude and phase values of the vibration waveform for the fundamental frequency component of repetitive vibration and its integer harmonic components is compared with the vibration waveform data set, and the fundamental frequency of repetitive vibration Feedback control of the drive command waveform data set composed of the amplitude and phase of the drive command waveform for the vibration system for the component and its integer harmonic component
A control method for an oscillator device for driving the vibration system based on the drive command waveform data set,
A detection step of detecting an amplitude ratio or phase difference between the drive command waveform data set and the vibration waveform data set for a fundamental frequency component of repetitive vibration and an integer harmonic component thereof;
Based on the detected amplitude ratio or phase difference, the frequency at which the rate of change of the amplitude ratio or phase difference in the vibration system is maximum does not match the fundamental frequency of repetitive vibration and its integer harmonic frequency. A control step for controlling at least one of a fundamental frequency of repetitive vibration and a resonance frequency of the vibration system;
A control method for an oscillator device characterized by comprising: The control step includes
Estimating a frequency at which a change rate of the amplitude ratio or the phase difference is maximized;
Selecting a frequency component of two consecutive orders in the vicinity of a frequency that gives a maximum rate of change of the amplitude ratio or the phase difference from the fundamental frequency component of the repetitive vibration and the integer harmonic component thereof;
Calculating a correction value of the fundamental frequency of the repetitive vibration or the resonance frequency of the vibration system so that the change rate of the amplitude ratio or the phase difference of the frequency components of the two consecutive orders matches.
The method of controlling an oscillator device according to claim 7, comprising: The control step includes
Selecting a set of frequency components consisting of two frequency components from the fundamental frequency component of the repetitive vibration and its integer harmonic components;
For a selected set of frequency components, B / A, where A is the rate of change of the amplitude ratio or phase difference in one frequency component and B is the rate of change of the amplitude ratio or phase difference in the other frequency Calculating a correction value of the fundamental frequency of the repetitive vibration or the resonance frequency of the vibration system so that the value of the frequency coincides with a predetermined value determined from the set of frequency components;
The method of controlling an oscillator device according to claim 7, comprising: The control step includes
Selecting a plurality of sets of frequency components, and calculating each of the correction values in a plurality of sets;
Determining a correction value of a fundamental frequency of repetitive vibration or a resonance frequency of the vibration system from the correction values obtained in a plurality of sets;
The method of controlling an oscillator device according to claim 9, comprising:

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