JP2009237239A - Optical scanner and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanner where fatigue breakdown during a plotting process is prevented. <P>SOLUTION: The optical scanner 10 comprises an optical scanner part 1, which is turnably configured and a driving part 4 for turn-driving the optical scanner part 1, and scans an object with the light reflected by the optical scanner part 1 by turning the optical scanner part 1. The optical scanner, further, includes a resonance frequency detecting part 7, which detects the resonance frequency of the optical scanner part 1 and a driving stop and control part 8 which stops the driving of the optical scanner part 1, when the resonance frequency of the optical scanner part 1 is equal to or lower than a predetermined threshold. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical scanner device and an image forming apparatus.

As an optical device that is used in a projector, a laser printer, or the like and performs drawing by optical scanning, an optical device that uses a torsional vibrator is known for the purpose of downsizing.
For example, in the optical device described in Patent Document 1, a light reflecting part made of aluminum is directly provided on a plate-like movable part made of silicon by a pair of torsion springs on both sides thereof. It is supported so that it can rotate. Then, optical scanning is performed by rotating (vibrating) the movable portion while twisting and deforming the pair of torsion springs. When such an optical device is used for a long time, the torsion spring may be fatigued.

By the way, in a projector or a laser printer, if the movable part of the optical device is destroyed during the drawing process, the laser light irradiated on the light reflecting part may leak out of the apparatus and directly enter the eyes of the user. Stopping the operation before the optical device breaks is an important safety issue.

On the other hand, when such an optical device is used for a long time, a part of the light irradiated to the light reflecting part becomes heat and the moving part rises in temperature, and the material property of the torsion spring changes, and the resonance of the moving part There is a tendency for the frequency to decrease.
Japanese Patent Laid-Open No. 7-92409

Therefore, the present invention provides an optical scanner device and an image forming apparatus that can stop driving before fatigue failure by grasping the driving state of the optical scanner by using the change over time of the resonance frequency. Objective.

An optical scanner device according to the present invention includes a mirror unit configured to be rotatable about a predetermined axis, and a drive unit for rotating the mirror unit, and rotates the mirror unit. Thus, an optical scanner device that scans an object reflected by the light reflected by the mirror unit, the resonance frequency detection unit for detecting the resonance frequency of the mirror unit, and the resonance frequency of the mirror unit is a predetermined threshold or less In this case, a drive stop control unit for stopping the drive of the mirror unit is provided.

According to the present invention, it is possible to stop the driving of the mirror unit before the fatigue breakage by grasping the driving state of the mirror unit by using the temporal change of the resonance frequency of the mirror unit.

In addition, the mirror unit includes a mass part including a light reflecting part having light reflectivity, a support part for supporting the mass part, and a connecting part for rotatably connecting the mass part to the support part. The connecting portion includes an elastic portion, and the mirror portion can be rotated while torsionally deforming the elastic portion by operating the driving portion.

The resonance frequency detection unit detects the resonance frequency of the mirror unit at startup, and the drive stop control unit stops driving of the mirror unit when the detected resonance frequency is equal to or lower than the threshold value. Is desirable.
At the time of start-up, since the process of acquiring the resonance frequency is always performed so that the drive unit can drive at the resonance frequency of the mirror unit itself, the acquired resonance frequency can be reused and efficient processing becomes possible. .

In addition, the resonance frequency detection unit detects a resonance frequency of the mirror unit after activation and is not irradiated with the light, and the drive stop control unit detects the detected resonance. When the frequency is equal to or lower than the threshold value, the driving of the mirror unit may be stopped.
By periodically acquiring the resonance frequency during a period in which the mirror unit is not irradiated with light, the latest state of the mirror unit can be grasped even when a long time has elapsed since startup.

A drive stop notification unit for notifying that the driving of the mirror unit will be stopped soon when the difference between the resonance frequency detected by the resonance frequency detection unit and the threshold value is equal to or less than a predetermined value; Is desirable.
As a result, the user can know in advance the parts replacement time and the like, and can be prevented from suddenly stopping and receiving inconvenience.

Based on the drive detection unit that detects the drive state of the mirror unit during the light irradiation period, and the drive state of the mirror unit that is detected by the drive detection unit, the drive unit detects the mirror unit itself. A drive control unit that controls to drive at the resonance frequency of the mirror unit, and the drive stop control unit, when the resonance frequency of the mirror unit detected by the drive detection unit is less than or equal to the threshold value, The drive is stopped.
Accordingly, the resonance frequency can be acquired even during a period in which the mirror portion is irradiated with light, the driving state of the mirror portion can be grasped, and the mirror portion can be reliably prevented from being broken during driving.

A temperature measurement unit that measures a temperature around the mirror unit, wherein the resonance frequency detection unit corrects the detected resonance frequency of the mirror unit based on the ambient temperature measured by the temperature measurement unit; desirable.
It is desirable to measure the resonance frequency in the same temperature state. However, according to the present invention, even if the ambient temperature changes, the change in temperature condition can be compensated for by correction.

An image forming apparatus according to the present invention is an image forming apparatus provided with the above optical scanner device,
The drive unit rotates the mirror unit to scan the light reflected by the mirror unit to form an image on the object.
The control by the drive control unit is preferably performed every scan.
As a result, the resonance frequency of the mirror portion changes and the amplitude becomes extremely small, and the width in the scanning direction of the output image is not constant for each scan, and the image can be prevented from being distorted.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of an optical scanner device 10 according to the first embodiment. As shown in the figure, the optical scanner device 10 includes an optical scanner unit (mirror unit) 1, a drive unit 4, a drive detection unit 5, a drive control unit 6, a resonance frequency detection unit 7, a drive stop control unit 8, and a drive stop notification. Part 9 is provided.

The optical scanner device 10 can be preferably applied to an image forming apparatus such as a projector, a laser printer, an imaging display, a barcode reader, a scanning confocal microscope, and the like. As a result, an image forming apparatus having excellent drawing characteristics can be provided.
For example, a projector (image forming apparatus) 90 as shown in FIG. 2 will be described. For convenience of explanation, the longitudinal direction of the screen S is referred to as “lateral direction (horizontal direction)”, and the direction perpendicular to the longitudinal direction is referred to as “vertical direction (vertical direction)”.

The projector 90 includes light source devices 911, 912, 913 that emit light such as a laser, a cross dichroic prism 92, a pair of optical scanner devices 93, 94, and a fixed mirror 95.
The light source devices 911, 912, and 913 respectively include a red light source device 911 that emits red light.
A blue light source device 912 that emits blue light and a green light source device 913 that emits green light.
The cross dichroic prism 92 is configured by bonding four right-angle prisms,
It is an optical element that combines light emitted from each of the red light source device 911, the blue light source device 912, and the green light source device 913.

Such a projector 90 synthesizes light emitted from each of the red light source device 911, the blue light source device 912, and the green light source device 913 based on image information from a host computer (not shown) by a cross dichroic prism 92, The combined light is scanned by the optical scanner devices 93 and 94 and further reflected by the fixed mirror 95 to form a color image on the screen S.
Here, the optical scanning of the optical scanner devices 93 and 94 will be specifically described.

First, the light combined by the cross dichroic prism 92 is scanned in the horizontal direction by the optical scanner device 93 (hereinafter also referred to as “main scanning”). The light scanned in the horizontal direction is further scanned in the vertical direction by the optical scanner device 94 (hereinafter also referred to as “sub-scan”). Thereby, a two-dimensional color image can be formed on the screen S.
By using the optical scanner device according to the present invention as such optical scanner devices 93 and 94, it is possible to provide a projector 90 that is small in size and has excellent drawing characteristics.

In general, the rotation speed of the optical scanner device 94 that performs sub-scanning is lower than the rotation speed of the optical scanner 93 that performs main scanning. Generally, the rotation frequency of the optical scanner device 94 that performs sub-scanning is about 60 kHz, and the rotation frequency of the optical scanner device 93 that performs main scanning is 10 although it depends on the type and size of the image to be formed. It is about ~ 256kHz. From this point of view, by using the optical scanner device of the present invention as the optical scanner devices 93 and 94, an optical scanner device having a torsion spring constant suitable for each of main scanning and sub-scanning can be easily provided. Can do. Therefore, it is possible to provide a projector 90 that is small and exhibits excellent drawing characteristics. However, the configuration of the projector 90 is not particularly limited as long as a color image can be formed on the screen S.

Next, the configuration and operation of the optical scanner unit 1, the drive unit 4, and the drive detection unit 5 will be described with reference to FIGS.
3 is a perspective view for explaining the configuration of the optical scanner unit 1, FIG. 4 is a cross-sectional view taken along line AA in FIG.
5 is a diagram for explaining the configuration of the drive unit 4 and the drive detection unit 5, FIG. 6 is a cross-sectional view taken along the line BB of FIG. 1, and FIG. 7 is a circuit configuration diagram for explaining the drive detection unit 5. .
In the following, for convenience of explanation, the upper side of FIGS. 4 and 6 is referred to as “upper”, the lower side is referred to as “lower”, the right side is referred to as “right”, and the left side is referred to as “left”.

The optical scanner unit 1 includes a base 2 having a one-degree-of-freedom vibration system as shown in FIG. 3 and a support substrate 3 that supports the base 2. The optical scanner unit 1 is connected to a drive unit 4 for rotating the mass unit 21 and a drive detection unit 5 for detecting the drive state of the mass unit 21.
The base body 2 includes a mass portion 21, a pair of connecting portions 22 and 23, and a pair of support portions 24 and 25. Each of the connecting portions 22 and 23 is formed of an elastic portion having a longitudinal shape and elastically deformable. Therefore, hereinafter, for convenience of explanation, the connecting portion 22 is also referred to as “elastic portion 22”.
The connecting portion 23 is also referred to as “elastic portion 23”.

Such an optical scanner unit 1 is configured to rotate the mass unit 21 while twisting and deforming the pair of elastic units 22 and 23 by applying a voltage to a coil 43 described later. . At this time, the mass portion 21 rotates about the rotation center axis X shown in FIG.
The pair of elastic portions 22 and 23 are provided so as to be substantially symmetrical with respect to the mass portion 21 in a plan view of the mass portion 21 when not driven. In other words, the optical scanner unit 1 is formed so as to be substantially symmetrical with respect to the mass unit 21 in a plan view of the mass unit 21 when not driven.

The mass portion 21 is a plate-like resin provided so as to be surface-bonded to a plate-like silicon portion 211 made of silicon as a main material and a lower surface of the silicon portion 211 (a surface facing the support substrate 3). Part 212 and a light reflecting part 213 provided on the upper surface of the silicon part 211 (surface opposite to the resin part 212). That is, the mass part 21 includes the silicon part 211 and the resin part 21.
2 and the light reflecting part 213 have a laminated structure in which the silicon part 211 is laminated in the thickness direction. In other words, the mass part 21 includes the silicon part 211, the resin part 212, and the light reflecting part 213.
It is formed so as to be sandwiched between. A coil 43 described later is provided on the lower surface of the resin portion 212 (the surface opposite to the silicon portion 211).

The support part 24 is a plate-like silicon part 241 made of silicon as a main material, and a plate-like resin part 242 made so as to be surface-bonded to the lower surface of the silicon part 241 and made of a resin material as a main material. It has. That is, the silicon part 241 and the resin part 242 are laminated in the thickness direction. Similarly, the support part 25 is a plate-like silicon part 251 made of silicon as a main material, and a plate made of resin material as a main material provided so as to be surface-bonded to the lower surface of the silicon part 251. The resin part 252 is provided. Such a support 24
, 25, an amplifier circuit 52 described later is formed on the lower surface of the silicon portion 241 of the support portion 24.

The elastic part 22 connects the mass part 21 and the support part 24 so that the mass part 21 can be rotated with respect to the support part 24. Similarly, the elastic portion 23 connects the mass portion 21 and the support portion 25 so that the mass portion 21 can be rotated with respect to the support portion 25. Such elastic part 22 and elastic part 23 have the same shape and the same dimensions.
The elastic portion 22 and the elastic portion 23 are provided coaxially with each other, and the mass portion 21 is rotatable with respect to the support portions 24 and 25 with the rotation central axis (rotation axis) X as the rotation portion. .
The elastic portion 22 is provided with a stress detection element 51 described later. The elastic part 22 is
A silicon part 221 composed mainly of silicon and bonded to the silicon part 221;
It is comprised with the resin part 222 comprised by using the resin material as the main material.

The base 2 has a laminated structure of a silicon layer and a resin layer.
The silicon layer includes a silicon part 211 of the mass part 21 and a silicon part 221 of the elastic part 22.
The silicon part 231 of the elastic part 23, the silicon part 241 of the support part 24, and the silicon part 251 of the support part 25 are integrally formed.
On the other hand, the resin layer includes a resin part 212 of the mass part 21, a resin part 222 of the elastic part 22, a resin part 232 of the elastic part 23, a resin part 242 of the support part 24, and a resin part 252 of the support part 25. Are integrally formed. Such a resin material is not particularly limited as long as the mass portion 21 can be rotated, but various thermoplastic resins and various thermosetting resins can be used.

The substrate 2 is supported on the support substrate 3.
The support substrate 3 has a pair of convex portions 32 and 33 formed on the upper surface thereof (the surface on the side facing the base 2) at a position facing the support portion 24. In other words, the recess 30 is formed on the upper surface of the support substrate 3. The support substrate 3 supports the base 2 by bonding the upper surfaces of the convex portions 32 and 33 and the lower surfaces of the support portions 24 and 25.

Further, an opening 31 is formed in a portion corresponding to the mass portion 21 on the bottom surface of the recess 30. The opening 31 constitutes an escape portion that prevents contact with the support substrate 3 when the mass portion 21 rotates (vibrates). By providing the opening part (relief part) 31, the deflection angle (amplitude) of the mass part 21 can be set larger while preventing the entire optical scanner part 1 from being enlarged.

Note that the relief portion as described above does not necessarily have to be opened (opened) on the lower surface of the support substrate 3 (surface opposite to the base 2) as long as the above-described effect can be sufficiently exerted. In other words, the escape portion can also be configured by a recess formed on the upper surface of the support substrate 3. Also, the recess 3
When the depth of 0 (height of the convex portions 32 and 33) is larger than the deflection angle (amplitude) of the mass portion 21, the opening 31 may not be provided. Further, the support substrate 3 may be omitted depending on the shape of the support portions 24 and 25 of the base 2. The support substrate 3 is made of, for example, glass or silicon as a main material.

Next, the drive part 4 for rotating the mass part 21 is demonstrated using FIG. FIG.
These are the fragmentary sectional enlarged views of the lower surface (surface which opposes the support substrate 3) of the base | substrate 2. FIG.
The drive unit 4 is opposed to the coil 43 provided in the resin unit 212 of the mass unit 21, an AC power supply 44 that applies a voltage to the coil 43, and the mass unit 21 in a direction perpendicular to the rotation center axis X. It has a pair of magnets 41 and 42 provided so as to. The drive unit 4 vibrates the mass unit 21 with respect to the support units 24 and 25 by applying an AC voltage from the AC power supply 44 to the coil 43 (
It is configured to rotate).

The coil 43 is formed in a spiral shape over almost the entire lower surface of the resin portion 212 of the mass portion 21 (surface opposite to the silicon portion 211). Since the resin part 212 functions as an insulating layer, a short circuit between the wirings of the coil 43 can be prevented. The patterning shape of the coil 43 is not limited to a spiral shape as long as the mass portion 21 can be rotated.

One of both ends of the electric wire (wiring) forming the coil 43 is connected to a terminal 431 provided on the support portion 24, and the other is connected to a terminal 432 provided on the support portion 25.
An AC power supply 44 is connected to the terminals 431 and 432, and the AC power supply 44 can generate a magnetic field from the coil 43 by applying an AC voltage to the coil 43.

The magnet 41 and the magnet 42 are connected to the rotation center axis X via the mass portion 21 in a plan view of the mass portion 21.
Are provided opposite to each other in a direction perpendicular to. Further, the magnets 41 and 42 are provided so that the surface of the magnet 41 facing the magnet 42 and the surface of the magnet 42 facing the magnet 41 are different magnetic poles.
Although it does not specifically limit as magnets 41 and 42, permanent magnets (hard magnetic material), such as a neodymium magnet, a ferrite magnet, a samarium cobalt magnet, and an alnico magnet, can be used conveniently.

The drive unit 4 rotates (drives) the mass unit 21 as follows.
For convenience of explanation, as shown in FIG. 5, as a representative case, the surface of the magnet 41 facing the magnet 42 is an S pole, and the surface of the magnet 42 facing the magnet 41 is an N pole. explain. Further, the upper side of FIG. 6 is “upper” and the lower side is “lower”.
First, a case where current is passed through the coil 43 from the terminal 431 to the terminal 432 by the AC power supply 44 (hereinafter referred to as “first state”) will be described. In this case, a downward electromagnetic force in FIG. 6 acts on the portion of the mass portion 21 closer to the magnet 42 than the rotation center axis X (Fleming's left-hand rule). On the other hand, an upward electromagnetic force acts in FIG. 6 on a portion of the mass portion 21 closer to the magnet 41 than the rotation center axis X. Thereby, the mass part 21 rotates counterclockwise around the rotation center axis X.

On the other hand, when a current is passed through the coil 43 from the terminal 432 to the terminal 431 by the AC power supply 44 (hereinafter referred to as “second state”), the magnet 42 in the mass portion 21 is located more than the rotation center axis X. On the side, an upward electromagnetic force is generated in FIG. On the other hand, a lower electromagnetic force is generated in FIG. 6 on the magnet 41 side of the mass portion 21 with respect to the rotation center axis X. Thereby, mass part 21
Rotates clockwise about the rotation center axis X.

And by repeating such a 1st state and a 2nd state alternately, elastic part 2
The mass part 21 can be rotated with respect to the support part 24 while twisting and deforming 2 and 23.
Furthermore, by using the AC power supply 44 as the voltage application means, the first state and the second state can be switched periodically and smoothly, and the mass portion 21 can be smoothly rotated. . However, as a voltage application means, if a voltage can be applied to the coil 43,
For example, a DC power supply may be used. In this case, for example, the mass portion 21 can be rotated with respect to the support portion 24 by intermittently applying a DC voltage to the coil 43.

Next, the drive detection part 5 which detects the drive state of the mass part 21 is demonstrated.
As shown in FIGS. 5 and 7, the drive detection unit 5 includes a stress detection element 51 provided on the lower surface (surface on the resin portion 222 side) of the silicon portion 221 of the elastic portion 22 and the silicon portion 24 of the support portion 24.
1 and an amplification circuit 52 that is electrically connected to the stress detection element 51. A plurality of through holes 53 for connecting the stress detection element 51 and the amplifier circuit 52 are formed in the resin portion 242 of the support portion 24. Further, the resin portion 242 of the support portion 24 has an input terminal 52.
1 and an output terminal 522 are formed, and these are electrically connected to the amplifier circuit 52, respectively. As the stress detection element 51, for example, a piezoresistive element (can be used).

The drive detection unit 5 is configured to detect the drive state of the mass unit 21 based on a signal from the amplification circuit 52. Specifically, the stress detection element 51 has a property that the resistance value changes in accordance with the amount of deformation. By providing such a stress detection element 51 on the elastic part 22, the resistance value of the stress detection element 51 can be changed corresponding to the degree of torsional deformation (swing angle) of the elastic part 22.
By changing the resistance value of the stress detection element 51, the current value (electric signal) flowing through the stress detection element 51 changes, and the change in the electric signal is amplified by the amplification circuit 52. Based on the amplified signal, The driving state of the mass unit 21 is detected. Thereby, the drive state of the vibration system of the optical scanner unit 1 can be detected more accurately.
In addition, since the change of the current value (electric signal) based on the resistance value change of the stress detection element 51 is weak, the electric signal is amplified by the amplifier circuit 52 as in the present embodiment, so that the mass part 21 The driving state can be detected more accurately. The amplifier circuit 52 is formed in the silicon portion 241 of the support portion 24.

8 and 9 are diagrams for explaining the principle of detecting the driving state of the mass portion 21 when the piezoresistive element 105 c is used as the stress detecting element 51.
As shown in FIG. 8, the piezoresistive element 105 c is installed in the elastic part 22 of the optical scanner unit 1, and as shown in FIG. 9, the output corresponding to the torsional motion of the optical scanner unit 1 is output from the piezoresistive element 105 c. Is obtained. For this reason, the amplitude, phase, and frequency of the vibration system of the optical scanner unit 1 are obtained.

As another example of the drive detection unit 5, as shown in FIGS. 10 and 11, two photodiodes (PD) 105a and 105b can be used.
As shown in FIG. 10, two photodiodes 105a and 105b are arranged side by side, and at the moment when the light deflected by the optical scanner unit 1 passes, the photodiodes 105a and 1b.
A pulse is output from 05b. The torsional vibration motion of the optical scanner unit 1 is the photodiode 1
It can be represented by a sine waveform connecting the output values of 05a and 105b. As a result, the amplitude, phase, and frequency of the vibration system of the optical scanner unit 1 are obtained.

Next, the operation of the drive control unit 6 will be described.
The drive control unit 6 controls the operation of the drive unit 4 based on the detection result of the drive detection unit 5. The drive control unit 6 adjusts the frequency of the voltage applied by the AC power supply 44 based on the signal from the amplifier circuit 52, and controls the vibration system of the optical scanner unit 1 to vibrate at its own resonance frequency. Thereby, the light reflection part 213 of the optical scanner part 1 can be displaced greatly, and the scanning angle by the optical scanner part 1 can be enlarged.

A frequency characteristic as shown in FIG. 12 exists between the amplitude (swing angle) of the vibration system of the optical scanner unit 1 and the drive frequency. As shown in the figure, the drive frequency is the resonance frequency f0 of the vibration system.
The maximum amplitude is obtained. However, when a part of the light irradiated to the light reflecting portion 213 becomes heat and the temperature of the elastic portions 22 and 23 rises, the physical properties of the material constituting the elastic portions 22 and 23 change, and the resonance frequency changes. End up. In order to obtain the maximum amplitude of the vibration system, it is necessary to change the frequency of the voltage applied from the AC power supply 44 in accordance with the resonance frequency of the vibration system. If driving is continued without changing the applied voltage, the amplitude becomes extremely small, the width of the output image in the scanning direction is not constant, and the image is distorted. Therefore, the optical scanner device 10 according to the present embodiment adjusts the frequency of the voltage applied by the AC power supply 44 by feeding back the detection result of the drive detection unit 5.

Next, operations of the resonance frequency detection unit 7 and the drive stop control unit 8 will be described. The resonance frequency detection unit 7 detects the resonance frequency of the vibration system of the optical scanner unit 1. The resonance frequency detector 7
The resonance frequency can be detected by the same method as that of the drive detection unit 5.

The resonance frequency detection unit 7 acquires the resonance frequency of the vibration system of the optical scanner unit 1 when the projector 90 is activated. The resonance frequency detection unit 7 supplies the acquired resonance frequency to the drive stop control unit 8. The drive stop control unit 8 compares the supplied resonance frequency with a predetermined threshold value. The threshold value is a frequency that is lower than the reference resonance frequency (initial value) by a predetermined value or more. The initial value can be, for example, a resonance frequency measured at the time of product shipment or a resonance frequency measured at the time of initial activation. As the operation time of the optical scanner unit 1 increases, the resonance frequency tends to decrease. This is because part of the light applied to the light reflecting portion 213 becomes heat, and when the temperature of the elastic portions 22 and 23 rises, the physical properties of the materials constituting the elastic portions 22 and 23 change. Therefore, the fact that the resonance frequency has decreased by a predetermined value from the initial value can be used as an indicator of fatigue failure due to deterioration with time of the optical scanner unit 1. The predetermined value is determined in advance by an experiment or the like.

When it is determined that the resonance frequency is equal to or less than the threshold value, the drive stop control unit 8 controls the operation of the drive unit 4 to stop the drive of the optical scanner unit 1.
By stopping the optical scanner unit 1 when the resonance frequency becomes lower than a predetermined threshold value, the optical scanner unit 1 is fatigued and destroyed during the drawing process, thereby preventing an accident that the laser beam leaks out of the apparatus. be able to.

When the drive detection unit 5 detects the drive state of the vibration system of the optical scanner unit 1 at the time of activation, the detection result of the resonance frequency may be supplied from the drive detection unit 5 to the drive stop control unit 8. Good.

In addition, the resonance frequency detection unit 7 acquires the resonance frequency of the vibration system of the optical scanner unit 1 during the period in which the light reflection unit 213 is not irradiated with light after the projector 90 is activated, and the drive stop control unit 8. You may make it supply to. By acquiring the resonance frequency periodically during the period when the light reflecting unit 213 is not irradiated with light after startup, the latest state can be grasped even when a long time has passed since startup. Since it is not preferable from the viewpoint of safety that the optical scanner unit 1 is fatigued during the period in which the light reflecting unit 213 is irradiated with light (during the drawing process), the light reflecting unit 21
The safety of the apparatus can be improved by periodically inspecting the resonance frequency during a period when light is not irradiated to 3 (other than the drawing process period).

In addition, the optical scanner device 10 according to the present embodiment includes a drive stop notification unit 9. The drive stop notification unit 9 notifies that the operation of the projector 90 will stop soon when the drive stop control unit 8 determines that the resonance frequency of the vibration system of the optical scanner unit 1 is equal to or lower than the threshold value.
The notification method includes, for example, a method of displaying a message on a part of the display image by the projector 90, turning on a lamp of the apparatus main body, displaying a message on an operation screen, and notifying by sound through a speaker. .
In this way, by notifying the stop of the operation of the projector 90 in advance, the user can know in advance the parts replacement time and the like, and can be prevented from suddenly stopping and receiving inconvenience.

FIG. 13 is a block diagram showing a configuration of an optical scanner device according to a modification of the first embodiment of the present invention. As shown in the figure, the optical scanner device 10 includes a temperature measurement unit 11. The temperature measurement unit 11 measures the temperature in the vicinity of the elastic units 22 and 23 and displays the measurement result as the resonance frequency detection unit 7.
To supply. The resonance frequency detection unit 7 corrects the detected resonance frequency based on the supplied measurement result, and supplies the corrected resonance frequency to the drive stop control unit 8.

Specifically, the resonance frequency detection unit 7 calculates a change amount (correction value) due to a temperature change of the resonance frequencies of the elastic units 22 and 23 based on the temperature information output from the temperature measurement unit 11. The obtained correction value corresponds to a deviation from the resonance frequency (reference frequency) of the vibration system in the initial state.
The reference frequency may be a predetermined constant resonance frequency or the latest measured resonance frequency.

As shown in FIG. 12, the resonance frequency of the vibration system of the optical scanner unit 1 changes under the influence of a part of the light irradiated to the light reflecting unit 213 becoming heat. Although it is desirable to measure the resonance frequency at the same temperature, according to the present embodiment, even if the ambient temperature of the vibration system changes, the change in temperature condition can be compensated for by correction.

The measurement temperature is supplied to the resonance frequency detection unit 7 at the same timing as the resonance frequency detection unit 7 detects the resonance frequency of the vibration system of the optical scanner unit 1. The measurement temperature may be supplied to the resonance frequency detection unit 7 at a timing different from the detection of the resonance frequency of the vibration system of the optical scanner unit 1 by the resonance frequency detection unit 7.

Further, the amount of light applied to the light reflection unit 213 may be provided to the resonance frequency detection unit 7. That is, for example, based on image information held by the host computer of the projector 90, the irradiation amount of light emitted from the light source devices 911, 912, 913 is calculated and provided to the resonance frequency detection unit 7. The resonance frequency detection unit 7 can obtain a necessary correction value based on the irradiation amount of the supplied light, and can correct the detected resonance frequency.

As described above, according to the first embodiment, the resonance frequency detection unit 7 detects the resonance frequency of the vibration system of the optical scanner unit 1, and the drive stop control unit 8 determines that the detected resonance frequency is equal to or less than a predetermined threshold value. If it is determined that the optical scanner unit 1 is stopped by controlling the operation of the drive unit 4, the optical scanner unit 1 is used as an index that the resonance frequency is lower than a predetermined threshold.
By grasping the driving state, the driving can be stopped before the optical scanner unit 1 is fatigued.

Further, the drive stop notification unit 9 may notify the stop of the operation of the projector 90 in advance, so that the user can know in advance the parts replacement time and the like, and the apparatus is suddenly stopped and inconvenienced. Can be prevented.

In addition, the structure of each part of the optical scanner device 10 of the present invention can be replaced with an arbitrary structure that exhibits the same function, and an arbitrary structure can be added.

Embodiment 2. FIG.
FIG. 14 is a block diagram showing a configuration of the optical scanner device 15 according to the second embodiment. As shown in the figure, the optical scanner device 15 includes an optical scanner unit (mirror unit) 1, a drive unit 4, a drive detection unit 5, a drive control unit 6, a resonance frequency detection unit 7, and a drive stop control unit 8. Yes.

In the second embodiment, the resonance frequency of the vibration system of the optical scanner unit 1 detected by the drive detection unit 5 is
The driving of the optical scanner unit 1 is also stopped when it is below the predetermined threshold.
Similar to the first embodiment, the drive detection unit 5 periodically detects the resonance frequency of the vibration system of the optical scanner unit 1 during the drawing process. In the second embodiment, the resonance frequency detected by the drive detection unit 5 is supplied to the drive stop control unit 8. The drive stop control unit 8 controls the operation of the drive unit 4 to stop driving the optical scanner unit 1 when the supplied resonance frequency is equal to or lower than a predetermined threshold value. Other operations of the optical scanner device 15 according to the second embodiment are the same as those of the first embodiment.

According to the second embodiment, the resonance frequency is acquired from the drive detection unit 5 even during the period in which the light reflection unit 213 is irradiated with light (during the drawing process), and the drive state of the optical scanner unit 1 is grasped. Therefore, it is possible to reliably prevent the optical scanner unit 1 from being broken during driving.

It is a block diagram which shows the structure of the optical scanner apparatus by Embodiment 1 of this invention. 1 is a schematic diagram for explaining an image forming apparatus of the present invention. It is a perspective view which shows the structure of an optical scanner part. FIG. 4 is a sectional view taken along line AA in FIG. 3. It is a figure for demonstrating a drive part. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is a figure for demonstrating a drive detection part. It is a figure for demonstrating the principle which detects the drive state of a mass part in the case of using a piezoresistive element as a stress detection element. It is a figure for demonstrating the principle which detects the drive state of a mass part in the case of using a piezoresistive element as a stress detection element. It is a figure for demonstrating the principle of the drive detection part using a photodiode. It is a figure for demonstrating the principle of the drive detection part using a photodiode. It is a figure which shows the relationship between the amplitude of the vibration system of an optical scanner part, and a drive frequency. It is a block diagram which shows the structure of the optical scanner apparatus by the modification of Embodiment 1 of this invention. It is a block diagram which shows the structure of the optical scanner apparatus by Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical scanner part, 10 Optical scanner apparatus, 2 Base | substrate, 21 Mass part, 211 Silicon part, 212 Resin part, 213 Light reflection part, 22, 23 Elastic part (connection part), 221, 23
1 Silicon part, 222, 232 Resin part, 24, 25 Support part, 241, 251 Silicon part, 242, 252 Resin part, 3 Support substrate, 30 Recess (space), 31 Opening part (
Escape part), 32, 33 convex part, 4 drive part, 41, 42 magnet, 43 coil, 431,
432 terminals, 44 AC power supply (voltage application means), 5 drive detection unit, 51 stress detection element, 52 amplifier circuit (semiconductor circuit), 521 input terminal, 522 output terminal, 53 through hole, 6 drive control unit, 7 resonance frequency Detection unit, 8 drive stop control unit, 9 drive stop notification unit,
DESCRIPTION OF SYMBOLS 11 Temperature measurement part, 90 Projector, 911 Red light source device, 912 Blue light source device, 913 Green light source device, 92 Cross dichroic prism, 93, 94 Optical scanner, 95 Fixed mirror

Claims (9)

A mirror portion configured to be rotatable around a predetermined axis;
A drive unit for rotationally driving the mirror unit,
An optical scanner device that scans the object reflected by the mirror unit by rotating the mirror unit,
A resonance frequency detection unit for detecting a resonance frequency of the mirror unit;
An optical scanner device comprising: a drive stop control unit that stops driving of the mirror unit when a resonance frequency of the mirror unit is equal to or lower than a predetermined threshold value. The mirror part is
A mass part provided with a light reflecting part having light reflectivity;
A support part for supporting the mass part;
A connecting part that rotatably connects the mass part to the support part,
The connecting portion includes an elastic portion,
The optical scanner device according to claim 1, wherein the mirror unit is rotated while the elastic unit is twisted and deformed by operating the driving unit. The resonance frequency detection unit detects a resonance frequency of the mirror unit at startup,
3. The optical scanner device according to claim 1, wherein the drive stop control unit stops driving the mirror unit when the detected resonance frequency is equal to or lower than the threshold value. The resonance frequency detection unit detects a resonance frequency of the mirror unit after startup and in a period in which the light is not irradiated on the mirror unit,
4. The optical scanner according to claim 1, wherein the drive stop control unit stops driving the mirror unit when the detected resonance frequency is equal to or lower than the threshold value. 5. apparatus. A drive stop notification unit for notifying that the drive of the mirror unit will be stopped soon if the difference between the resonance frequency detected by the resonance frequency detection unit and the threshold value is less than or equal to a predetermined value; 5. The optical scanner device according to claim 1, wherein the optical scanner device is characterized in that: A drive detection unit for detecting a drive state of the mirror unit during a period of irradiation with the light;
A drive control unit that controls the drive unit to drive the mirror unit at its resonance frequency based on the drive state of the mirror unit detected by the drive detection unit;
6. The drive stop control unit stops driving the mirror unit when a resonance frequency of the mirror unit detected by the drive detection unit is equal to or lower than the threshold value. An optical scanner device according to any one of the above. A temperature measuring unit for measuring the temperature around the mirror unit;
The said resonance frequency detection part correct | amends the resonance frequency of the said mirror part detected based on the ambient temperature measured by the said temperature measurement part, The Claim 1 characterized by the above-mentioned. Optical scanner device. An image forming apparatus comprising the optical scanner device according to any one of claims 1 to 7,
An image forming apparatus that forms an image on an object by scanning the light reflected by the mirror unit when the driving unit rotates the mirror unit. The image forming apparatus according to claim 8, wherein the control by the drive control unit is performed for each scan.

Images