Optical scanner

The present invention relates to an optical scanning device using a deflection mirror.

In recent years, an optical scanning device that scans an optical beam has been used for scanning an optical beam in an optical disk, a laser printer, or the like. As an optical scanning device using these, a device having a configuration in which a minute mirror using silicon micromachining technology is oscillated has been proposed.

Such micromirror devices are roughly classified according to their drive methods, and electromagnetic drive methods and electrostatic drive methods have been proposed. Patent Document 1 proposes a method using a magnetic field generating means. Further, Patent Document 2 proposes a method using an electrostatic induction generating means. In such a conventional proposal, as a drive method for a movable part of a micromirror, a drive voltage is constantly applied as a sinusoidal AC signal in a drive method using a magnetic field generating means or a driving method using an electrostatic induction generating means. It is a method of driving.

As a typical example, FIG. 1 shows an optical scanning device that swings a mirror by an electrostatic attraction disclosed in Patent Document 3. In FIG. 1, a mirror 102 is arranged in a recess provided in the support substrate 101, and the mirror is supported by the support substrate 101 via an integrally provided torsion bar 103. Both sides of the mirror 102 can swing in the direction perpendicular to the plane of the mirror by the twisting action of the torsion bar 103.

The torsion bar 103 is made of a conductive member, and both ends thereof are electrically connected to a pad 104 provided on the support substrate 101. Further, fixed electrodes 107 are supported on both sides of the recesses of the support substrate 101 via insulators 106.

The fixed electrode 107 has a configuration in which the positional relationship with the mirror electrode portions 105 on both sides of the mirror 102 is arranged at a position higher than the initial position of the mirror electrode portion 105 along the swing direction, and the mirror electrode portion At the initial position of 105, the mirror electrode portion 105 and the fixed electrode portion 107 are arranged with a height difference.

This device applies a high voltage between the pad 108 of the fixed electrode 107 and the pad 104 to which the torsion bar 103 is connected to generate an electrostatic force between the fixed electrode 107 and the mirror 102, and the electrostatic attraction is generated. One side surface of the mirror 102 is attracted to the fixed electrode 107 side.

This suction operation twists and deforms the torsion bar 103 while swinging the mirror 102 in the direction perpendicular to the plane of the mirror. When the repression applied to the fixed electrode 107 is released immediately after this swinging operation, the mirror is swung in the opposite direction due to the torsional restoration force of the torsion bar 103.

By repeating this voltage application and stop, the mirror 102 can be swung, and by reflecting the light from the light source by the mirror 102, the light can be deflected and scanned.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2002-78368</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 8-211320</text></patcit><patcit num="3"><text>Japanese Patent No. 3011144</text></patcit><patcit num="4"><text>Japanese Unexamined Patent Publication No. 2000-162538</text></patcit><patcit num="5"><text>Japanese Unexamined Patent Publication No. 9-68666</text></patcit>

<p> In any of the above proposals, the swing angle of the mirror is configured to be used so as to obtain the maximum angle by swinging at a period at a resonance frequency that resonates with the natural frequency of the mirror movable member. However, in general, driving at a resonance frequency resonated with the natural frequency is used at a position where the Q value is high, so the driving frequency may be caused by fluctuations in the drive signal voltage or natural frequency fluctuations due to the temperature of the moving member. The swing angle of the mirror is reduced.</p><p> In order to keep the swing angle of the mirror constant, it is necessary to detect the swing position of the mirror and adjust the timing of driving the mirror. Further, when driving a plurality of mirrors at the same resonance frequency in a system using a plurality of mirrors, it is necessary to detect the swinging positions of the plurality of mirrors and drive them in synchronization with each other.</p><p> As described above, in order to apply the drive pulse in synchronization with the swing of the mirror in any case, it is necessary to measure the swing position of the mirror, and Patent Document 3 detects a change in the capacitance of the drive electrode. The position of the mirror is detected. Further, in Patent Document 1, a coil is used to detect the swing position of the mirror. Further, in Patent Document 5, the angle of the mirror is detected by detecting the light beam.</p><p> Further, conventionally, since the Q value is high and the deflection angle of the light beam is accurately detected, there are problems that it is necessary to install a large number of high-precision sensors, the detection circuit becomes complicated, and the manufacturing cost increases.</p><p> In view of these problems, an object of the present invention is to provide an optical scanning device that accurately detects the optical beam scanning position by the deflection mirror.</p>

<p> In order to solve the above problems, the present invention includes a light beam generating means for generating a light beam, a light beam deflecting means for incident the light beam and deflecting and emitting the light beam by a driveable deflection mirror. When the light beam deflected and scanned by the light beam deflection means scans and passes through a predetermined position, the position detection signal generation means that detects the light beam and outputs a position detection signal and the position detection signal according to the position detection signal. A synchronization reference signal generation means that generates a synchronization reference signal in synchronization with the drive cycle of the deflection mirror, a drive signal that drives the deflection mirror based on the synchronization reference signal, and a drive control of the deflection mirror. The deflection mirror driving means, the reference clock generating means for generating the reference clock for measuring the time difference between the position detection signals based on the synchronization reference signal, and the reference clock generating means for generating the reference clock, and the time difference between the arbitrary position detection signals are measured based on the reference clock. It is characterized by having a measuring means to be used.</p><p> Further, in order to solve the above problems, in the present invention, the position detection signal generation means is an optical sensor that detects the light beam and generates a position detection signal when the light beam scans and passes through a predetermined position. It is characterized by being.</p><p> Further, in order to solve the above problems, the present invention is characterized in that the optical sensor is provided both in the vicinity of the scanning start position and the vicinity of the scanning end position of the light beam based on the deflection mirror.</p><p> Further, in order to solve the above problems, the present invention is characterized in that the reference clock is newly generated every time in synchronization with the synchronization reference signal.</p><p> Further, in order to solve the above problems, in the present invention, the deflection mirror driving means sets a value measured based on a position detection signal generated by each optical sensor as a preset reference value. It is characterized in that the drive signal is generated and the deflection mirror is controlled.</p><p> Further, in order to solve the above problems, in the present invention, the deflection mirror driving means sets a value measured based on a position detection signal generated by each optical sensor as a preset reference value. It is characterized in that the voltage to the drive signal is controlled.</p><p> Further, in order to solve the above problems, in the present invention, the measured value is a value determined from the interval between the first position detection signal and the second position signal, which are signals generated by the optical sensor. It is characterized by being.</p><p> Further, in order to solve the above problems, the present invention is characterized in that the first and second position detection signals are signals generated by the same optical sensor.</p><p> Further, in order to solve the above problems, the present invention is characterized in that the first and second position detection signals are signals generated by different optical sensors.</p><p> Further, in order to solve the above problems, in the present invention, the scanning directions of the respective light beams detected when the optical sensor generates the first and second position detection signals are the same. It is characterized by.</p><p> Further, in order to solve the above problems, in the present invention, the scanning directions of the respective light beams detected when the optical sensor generates the first and second position detection signals are different directions. It is characterized by.</p><p> In order to solve the above problems, the present invention includes a movable member which is disposed said deflecting mirror, swingably supported to said movable member and a support member for lifting the deflecting mirror driving unit, It is characterized in that the movable member is oscillated in a frequency region excluding a resonance frequency that resonates with the natural frequency of the movable member.</p>

<p> As described above, the present invention can provide an optical scanning device that accurately detects the optical beam scanning position by the deflection mirror.</p>

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows an outline of a writing device using the optical scanning device according to the present embodiment. In FIG. 2, an example in which the beam generating means is a laser beam will be described.

In FIG. 2, a laser light source 200, a condenser lens 201, an aperture 202, a cylinder lens A203, a deflection mirror 40, an fθ lens 207, 208, an optical path change mirror 209, a cylinder lens B210, and a photoconductor 211 are shown. , Synchronous detection mirror 213 and optical sensors 215a, 215b are shown. The position detection signals generated by these 215a and 215b correspond to the first and second position detection signals.

The light beam emitted from the laser light source 200 is made into parallel light by the condenser lens 201, only the required beam diameter is taken out by the aperture 202 having a slit portion according to the dot size, and the appropriate beam diameter is taken out by the cylinder lens A203. Is formed in the lens, and is scanned in the main scanning direction, which is the long axis direction of the photoconductor, by the deflection mirror 40, which is an optical beam deflecting means.

An fθ lens 207,208 for converting equiangular scanning to constant velocity scanning, an optical path deflection mirror 209, and a cylinder lens B210 for condensing in the direction of rotation of the photoconductor are arranged on the optical path, and a minute laser beam is arranged on the surface of the photoconductor 211. The spot is imaged.

The beam folded back by the synchronization detection mirror 213 is applied to the optical sensor 215 to generate a synchronization signal. By providing the optical sensor in this way, the position of the optical beam can be detected.

In FIG. 2, the optical sensors 215a and 215b are arranged near the optical scanning start position or the optical scanning end position of the optical beam, respectively. By arranging the optical sensors at both ends of the scanning region of the light beam in this way, it is possible to monitor the scanning time for scanning the scanning effective region of the light beam.

Next, a block diagram of the optical scanning device will be described with reference to FIG. In FIG. 3, RAM 33, ROM 32, MPU 31, clock 30, address / data bus 34, drive signal generation timing control unit 36, programmable oscillator / drive signal generator 39, voltage variable unit 47, and Driver amplifier unit 41, optical beam generation unit 51, deflection mirror 40, optical sensors 215a and 215b, sensor amplifier unit 42, position signal generation unit 38, reference clock generation unit 48, and time measurement unit 49. , The synchronization signal generation unit 37 and the time difference calculation circuit 46 are shown.

Of these, the light beam generating unit 51 corresponds to the light beam generating means. The deflection mirror 40 corresponds to a light beam deflection means. The position detection signal generation unit 38 corresponds to the position detection signal generation means. The synchronization signal generation unit 37 corresponds to the synchronization signal generation means. The reference clock generation unit 48 corresponds to the reference clock generation means. The time measuring unit 49 corresponds to the measuring means.

The drive unit 500 composed of the voltage variable unit 47, the drive signal generation timing control unit 36, the programmable transmitter / drive signal generation unit 39, and the driver amplifier unit 41 makes the deflection mirror 40 of the optical scanning device 43 swingable. The drive unit 500 corresponds to the deflection mirror drive means.

The detection unit 520, which is composed of the sensor amplifier unit 42, the position detection signal generation unit 38, the synchronization reference signal generation unit 37, and the reference clock generation unit 48, detects and stores the signal extracted from the signal detection unit of the optical scanning device. .. The MPU31, ROM32, RAM33, and address / data bus 34 constitute the data signal processing unit 510.

The drive unit 500 sets the voltage applied to the electrodes in the voltage variable unit 47 according to the control instruction from the data signal processing unit 510, and the drive signal generation timing control unit 36 stores data on the drive frequency of the signal applied to the electrodes. Then, the programmable transmitter / drive signal generation unit 39 generates a drive frequency corresponding to the data stored in the drive signal generation timing control unit 36.

The signal generated by the programmable transmitter / drive signal generation unit 39 is connected to the driver amplifier unit 41. In the driver amplifier section 41, the signal applied voltage can be arbitrarily changed by the voltage variable section 47.

The output of the driver amplifier unit 41 is connected to a terminal arranged in the optical scanning device and gives a signal to each electrode. The detection unit amplifies the signal extracted from the signal detection unit of the optical scanning device by the sensor amplifier unit 42, generates the position detection signal by the position detection signal generation unit 38, and generates the position detection signal from the position detection signal by the synchronization reference signal generation unit 37. Generate a synchronization reference signal.

Further, the reference clock generation unit 48 generates a clock synchronized with the synchronization reference signal and uses it to measure the time between each synchronization reference signal. Data or commands are exchanged between the data signal processing unit 510, the drive unit 500, and the detection unit 520 via the address / data bus 34, and the data signal processing unit 510 operates according to a predetermined control processing procedure. Do.

The time chart of the operation in the optical scanning apparatus described above will be described with reference to FIG. Figures A to E are shown in FIG. Graph A shows the scanning locus of the light beam. Graph B shows each position signal detected by an optical sensor arranged near the optical scanning start position or the optical scanning end position. Graph C shows a synchronization reference signal. Graph D shows the reference clock generated. Graph E shows the drive signal.

When a drive signal of an arbitrary frequency is applied, the deflection mirror reciprocates, and a light beam trajectory having a simple vibration waveform shown in Graph A is generated. The optical sensors 215a and 215b are arranged near the optical scanning start position or the optical scanning end position of the optical beam, respectively, and the position signals detected by each are shown in Graph B of FIG. 3 as shown below. There is. PS (a, n), PS (b, n), PS (c, n), PS (d, n), PS (a, n + 1), PS (b, n + 1), PS (c, n + 1), PS (d, n + 1) ... (integer of n 1) Synchronizing with these position signals, the following synchronization reference signals shown in Graph C are generated. P (a, n), P (b, n), P (c, n), P (d, n), P (a, n + 1), P (b, n + 1), (c, n +1), P (d, n + 1), The drive timing of the optical scanning device is controlled with reference to these synchronization reference signals. Further, the reference clock shown in Graph D is generated in synchronization with the synchronization signals such as P (a, n), P (b, n), P (c, n), P (d, n). ..

The reference clock is newly generated each time in synchronization with the synchronization reference signal, and the time between arbitrary signals of the position signal is measured by this reference clock.

Next, with reference to FIG. 5, a case where the amplitude is the same and the sinusoidal vibration period fluctuates with respect to the standard sinusoidal vibration locus waveform will be described. The locus shown in FIG. 5 is a case where the period of the drive waveform is longer than that of the standard waveform. In this case, by measuring each timing of the signal obtained by the locus of the standard waveform, the fluctuation amount is corrected and controlled so as to be the same as the standard waveform.

Focusing on the signals in FIG. 5, the time T (a, 1) of S (a, n) and S (a, n + 1) of the standard signal and the signal PS (a, 1) obtained from the drive waveform Comparing the time T'(a, 1) of n) and PS (a, n + 1), T'(a, 1)&gt; T (a, 1).

Also, the time T (b, 1) of the standard signals S (b, n) and S (b, n + 1) and the signals PS (b, n) and PS (b, n + 1) obtained from the drive waveform. Comparing the time T'(b, 1) of), T'(b, 1)&gt; T (b, 1), and it is inferred from these facts that the period of the drive waveform is longer than that of the standard waveform.

Therefore, in order to reduce the cycle, the drive signal generation timing control unit 36 (see FIG. 3) changes the drive signal application timing and supplies it to the driver unit 41. At this time, the frequency change amount is determined by storing the frequency change amount in one clock unit of the reference clock as a change amount table in advance and referring to this change amount table.

In the case of Fig. 5, it can be realized by increasing the drive frequency. The application of the correction drive signal in FIG. 5 will be described.

As a result of the calculation at the time of detecting the position detection signal PS (a, n + 1), T'(a, 1)&gt; T (a, 1), and when it is detected that the drive cycle fluctuates and becomes long, it is driven. It is necessary to adjust the signal application timing. In this case, the drive signal HD1 is applied before and after the detection signal PS (b, n + 1) as the next drive signal from the time of PS (a, n + 1). At this time, the drive signal HD1 is applied so as to increase the swing speed of the deflection mirror by adjusting the timing Tn with reference to PS (a, n + 1).

Also, adjust the drive signal HD1 application time Tl time. Similarly, when T'(c, 1)&gt; T (c, 1) is obtained as the calculation result at the time of detection of the detection signal PS (c, n + 1), the detection signal PS (c, n + 1) is used as a reference. When the drive signal HD2 is applied, the timing Tn2 and the signal application time Tl2 are adjusted so that the speed increases.

The values of timing Tn, Tn2, application time Tl, and Tl2 are stored in advance as a change amount table as values in one clock unit of the reference clock, and are determined by referring to this change amount table.

By detecting the scanning position detection signal of the light beam in this way, it is possible to control the swing drive of the deflection mirror.

Next, the deflection mirror drive control will be described. FIG. 6 shows an example when the sinusoidal vibration frequency is the same and the amplitude fluctuates with respect to the standard sinusoidal vibration locus waveform, and the amplitude becomes larger than the standard waveform.

The control here is a control that corrects the fluctuation amount and makes it the same as the standard waveform by measuring each timing of the signal obtained by the locus of the standard waveform. Focusing on the signals in FIG. 6, the time tabs of the standard signals S (a, n) and S (b, n) and the signals PS (a, n) and PS (b, b, obtained from the drive waveforms) Comparing the time T'ab of n), T'ab&gt; Tab.

Also, comparing the time Tcd of the standard signals S (c, n) and S (d, n) with the time T'cd of the signals PS (c, n) and PS (d, n) obtained from the drive waveform. T'cd&gt; Tcd. From this, it is presumed that the amplitude of the drive waveform is larger than that of the standard waveform. Therefore, in order to reduce the amplitude, the applied voltage is variable by the voltage variable section 47 (see FIG. 3) and supplied to the driver amplifier section 41.

At this time, the amount of change in voltage is determined by storing the amount of potential change in one clock unit of the reference clock in advance as a amount of change table and referring to this amount of change table. In the case of FIG. 6, it can be realized by reducing the applied voltage.

Further, the deflection mirror drive control will be described with reference to FIG. FIG. 7 shows an example when the amplitude and the period fluctuate with respect to the standard sinusoidal vibration locus waveform, and shows the case where the period of the drive waveform is longer and the amplitude is larger than the standard waveform.

In this case, by measuring each timing of the signal obtained from the locus of the standard waveform, the fluctuation amount is corrected and controlled so as to be the same as the standard waveform. In FIG. 7, paying attention to the signal, the time T (a, 1) of S (a, n) and S (a, n + 1) of the standard signal and the signal PS (a, n) obtained from the drive waveform. Comparing the time T'(a, 1) of PS (a, n + 1) with T'(a, 1)&gt; T (a, 1). Also, the time T (b, 1) of the standard signals S (b, n) and S (b, n + 1) and the signals PS (b, n) and PS (b, n + 1) obtained from the drive waveform. ) Time T'(b, 1) is T'(b, 1)&gt; T (b, 1).

From this, it is presumed that the period of the drive waveform is longer than that of the standard waveform. Therefore, in order to reduce the period, the drive signal generation timing control unit 36 (see FIG. 3) changes the drive signal application timing and supplies it to the driver amplifier unit 41.

At this time, the frequency change amount is determined by storing the frequency change amount in one clock unit of the reference clock as a change amount table in advance and referring to this change amount table.

Next, the time Tab of the standard signals S (a, n) and S (b, n) is compared with the time T'ab of the signals PS (a, n) and PS (b, n) obtained from the drive waveform. Then T'ab&gt; Tab. Also, comparing the time Tcd of the standard signals S (c, n) and S (d, n) with the time T'cd of the signals PS (c, n) and PS (d, n) obtained from the drive waveform. T'cd&gt; Tcd.

From this, it is presumed that the amplitude of the drive waveform is larger than that of the standard waveform. Therefore, in order to reduce the amplitude, the applied voltage is variable by the voltage variable section 47 (see FIG. 3) and supplied to the driver 41 section.

The amount of change in voltage at this time is determined by referring to the amount of change table in which the amount of potential change in one clock unit of the reference clock is stored in advance. In the case of Fig. 7, it can be realized by reducing the applied voltage.

Even if the amplitude and period of the drive waveform fluctuate at the same time in this way, it is simply the same as the standard simple vibration waveform by performing the amplitude correction and cycle correction by detecting the optical beam scanning position in combination with each other. Can be done.

Next, the control algorithm will be described with reference to the flowchart of FIG. In step S101, the drive signals PS (a, n) and PS (b, n) are detected. In the next step S102, an operation for finding T'ab is performed. In the next step S103, the standard signals S (a, b) and S (b, n) are referenced.

In the next step S104, an operation for finding T'ab is performed. The obtained Tab and T'ab are compared in step S105. As a result of the comparison, if it is determined in step S106 that Tab and T'ab are equal, the process ends.

If Tab and T'ab are not equal, the magnitude relationship between Tab and T'ab is determined in step S107, and if Tab is larger, the drive signal applied voltage amount is calculated in step S108 to lower the potential. Is applied. When Tab is smaller, the amount of drive signal applied voltage is calculated in step S109, and the potential is increased and applied.

Next, the control algorithm will be described with reference to the flowchart of FIG. In step S201, the drive signals PS (a, n) and PS (a, n + 1) are detected. In the next step S202, an operation for finding T'(a, 1) is performed. In the next step S203, the standard signals S (a, n) and S (a, n + 1) are referenced.

In the next step S204, an operation for finding T (a, 1) is performed. The obtained T (a, 1) and T'(a, 1) are compared in step S205. As a result of the comparison, if it is determined in step S206 that T (a, 1) and T'(a, 1) are equal, the process ends.

If T (a, 1) and T'(a, 1) are not equal, step S207 determines the magnitude relationship between T (a, 1) and T'(a, 1) and T'(a, 1). If 1) is larger, the drive signal application frequency is calculated in step S208, and the frequency is increased and applied. When T (a, 1) is smaller, the drive signal application frequency is calculated in step S209, and the frequency is reduced and applied.

Next, the control algorithm will be described with reference to the flowcharts of FIGS. 10 and 11. This flowchart is a combination of the flowcharts of FIGS. 8 and 9.

In step S301, the drive signals PS (a, n) and PS (a, n + 1) are detected. In the next step S302, an operation for finding T'(a, 1) is performed. In the next step S303, the standard signals S (a, n) and S (a, n + 1) are referenced.

In the next step S304, an operation for finding T (a, 1) is performed. The obtained T (a, 1) and T'(a, 1) are compared in step S305. As a result of the comparison, if it is determined in step S306 that T (a, 1) and T'(a, 1) are equal, the process proceeds to step S310.

If T (a, 1) and T'(a, 1) are not equal, step S307 determines the magnitude relationship between T (a, 1) and T'(a, 1) and T'(a, 1). If 1) is larger, the drive signal application frequency is calculated in step S308, and the frequency is increased and applied. When T (a, 1) is smaller, the drive signal application frequency is calculated in step S309, and the frequency is reduced and applied.

From step S310, it is the flowchart of FIG. In step S311, the drive signals PS (a, n) and PS (b, n) are detected. In the next step S312, an operation for finding T'ab is performed. In the next step S313, the standard signals S (a, b) and S (b, n) are referenced.

In the next step S314, an operation for finding T'ab is performed. The obtained Tab and T'ab are compared in step S315. As a result of the comparison, if it is determined in step S316 that Tab and T'ab are equal, the process ends.

If Tab and T'ab are not equal, the magnitude relationship between Tab and T'ab is determined in step S317, and if Tab is larger, the drive signal applied voltage amount is calculated in step S318 to lower the potential. Is applied. If Tab is smaller, the amount of drive signal applied voltage is calculated in step S319, and the potential is increased and applied.

The above is the explanation of the processing contents. The implementation will be described below. First, the deflection mirror will be described with reference to FIG. The deflection mirror is formed using silicon micromachining technology.

This deflection mirror is composed of a silicon substrate 1, a support member 2, a fixed electrode 3, a movable member arrangement electrode 4, a mirror portion 9, and a movable member 10.

The silicon substrate 1 is formed of a rectangular single-layer thick plate. The movable member 10 is formed with a movable member disposing electrode 4 and a mirror portion 9. The support member 2 is integrally formed on both sides of the fixed electrode 3 and the movable member 10 so as to face the movable member-arranged electrode 4, and is fixed to a silicon substrate at both ends. As a result, the movable member 10 can swing in a direction perpendicular to the plane direction of the mirror portion 9 by twisting the support member 2.

A configuration in which this deflection mirror is installed on a base will be described. FIG. 13 shows the deflection mirror and the base 20. A contact 23 connected to a pad (not shown) of the deflection mirror is arranged on the base 20. FIG. 14 shows a state in which the deflection mirror is installed on the base 20 using the contact 23.

As described above, in an optical scanning device having a movable member provided with a deflection mirror and a support member for swingably supporting the movable member, and making the movable member swingable, the normal drive frequency is movable. It is often set to a resonance frequency that resonates with the natural frequency of the member.

This is because the swing angle of the movable member is maximized at the resonance frequency point. FIG. 15 is a swing characteristic diagram of the deflection mirror. In the swing characteristic diagram of FIG. 15, the resonance frequency region that resonates with the natural frequency of the movable member is narrow, and the driving object has a high Q value. Conventionally, since the Q value is high, there are problems that it is necessary to install a large number of high-precision sensors in order to accurately detect the deflection angle of the light beam, the detection circuit becomes complicated, and the manufacturing cost increases.

The drive frequency used in this embodiment is a method of driving the movable member using a frequency deviating from the resonance frequency in FIG. By using a frequency having a low Q value in this way, the fluctuation of the mirror swing angle with respect to the frequency fluctuation is small, that is, the fluctuation of the mirror swing angle is small even if the mirror drive frequency is changed.

Therefore, it becomes easy to control to reduce the occurrence of jitter and the like of the mirror swing characteristic, and when a plurality of mirrors are used, it is easy to match the drive frequencies of the plurality of mirrors. Further, the method of detecting the swing position of the mirror for applying the drive pulse can be simplified.

<figref num="1">It is a figure which shows the outline of the conventional optical scanner.</figref><figref num="2">It is a figure which shows an example of the optical writing apparatus using an optical scanning apparatus.</figref><figref num="3">It is a block diagram of an optical scanning apparatus drive apparatus.</figref><figref num="4">It is a figure which shows the optical scanning apparatus deflection beam scanning locus, signal detection, drive signal time chart.</figref><figref num="5">It is a figure which shows the state that the period of the light beam locus of an optical scanning apparatus fluctuates.</figref><figref num="6">It is a figure which shows the state that the amplitude of the light beam locus of an optical scanning apparatus fluctuated.</figref><figref num="7">It is a figure which shows the state which the period and the amplitude of the light beam locus of an optical scanning apparatus fluctuated.</figref><figref num="8">It is a flowchart which shows the correction drive control of the amplitude fluctuation of the optical beam locus of an optical scanning apparatus.</figref><figref num="9">It is a flowchart which shows the correction drive control of the periodic fluctuation of the optical beam locus of an optical scanning apparatus.</figref><figref num="10">It is a flowchart which shows the correction drive control of the period and the amplitude fluctuation of the optical beam locus of an optical scanning apparatus (the 1).</figref><figref num="11">It is a flowchart which shows the correction drive control of the period and the amplitude fluctuation of the optical beam locus of an optical scanning apparatus (the 2).</figref><figref num="12">It is a schematic block diagram of the deflection mirror which constitutes an optical scanning apparatus.</figref><figref num="13">It is a figure which shows the positional relationship which arranges an optical scanning apparatus on a base.</figref><figref num="14">It is a figure which shows the state which set the optical scanning apparatus on a base.</figref><figref num="15">It is a figure which shows the swing characteristic of an optical scanning apparatus.</figref>

Code description

1 Silicon substrate 2 Support member 3 Fixed electrode 4 Movable member Disposition electrode 9 Mirror part 10 Movable member 20 Base 23 Contact 30 Clock 31 MPU 32 ROM 33 RAM 34 Address / Data bus 36 Drive signal generation timing control 37 Synchronous reference signal 38 Position detection signal generator 39 Programmable oscillator / drive signal generator 40 Deflection mirror 41 Driver amplifier section 42 Sensor amplifier section 44 Optical beam generator section 46 Time difference calculation circuit 47 Voltage variable section 48 Reference clock generator section 49 Time measurement section 101 Board 102 Mirror 103 Torsion bar 104, 108 Pad 105 Mirror electrode part 106 Insulator 107 Fixed electrode 200 Multiple laser light sources 201 Collimated lens 202 Aperture 203 Cylinder lens A 207, 208 fθ lens 209 Folded mirror 210 Cylinder lens B 211 Photoreceptor 212 Imaging spot sequence 213 Synchronous detection mirror 215a, 215b Optical sensor