JP5402588B2 - Optical scanning device - Google Patents

Description

  The present invention relates to an optical scanning device.

Scan projectors of the two-mirror type (for example, a type that draws with two mirrors, a horizontal scanning mirror using resonance and a vertical scanning mirror such as a galvano mirror), emit light emitted from the light emitting unit to the projection surface. In addition to scanning in the horizontal direction (horizontal scanning: main scanning) and scanning in the vertical direction (vertical scanning: sub-scanning) at a scanning speed slower than the horizontal scanning speed, the projection surface An image (video) is drawn on top. The deflection angle (amplitude) about the rotation center axis of the horizontal scanning mirror is constant.
In such a scan projector, when drawing an image on the projection surface, distortion caused by the optical path difference to the projection surface, for example, in the horizontal direction (upper and lower sides of the image drawn on the projection surface) Since distortion called “trapezoidal distortion” having different lengths in the horizontal direction occurs, correction is necessary.

  By the way, as shown in FIG. 26, the locus of light on the projection surface 21 when the light is two-dimensionally scanned on the projection surface in the light emission state where the light is emitted from the light emitting portion of the scan projector 300. Among the plurality of drawing lines (scanning lines) 141, the left side portion of the left drawing limit line and the right side portion of the right drawing limit line each have a low angular velocity (speed) of the horizontal scanning mirror, and drawing is performed. Not suitable for. For this reason, an area between the left drawing limit line and the right drawing limit line on the projection surface 21 is used as a drawable area 143 in which an image can be drawn, and the image is stored in the drawable area 143. A drawing area 142, which is a drawing area, is set. That is, the drawable area 143 is divided into a drawing area 142 that is an area where an image is drawn and a non-drawing area that is an area where an image is not drawn. The drawing area 142 is located at the center of the drawable area 143 and is set to form a rectangle (including a square). The right and left portions of the drawing area 142 are non-drawing areas.

  In order to prevent (correct) the trapezoidal distortion, normally, as described above, the rectangular drawing area 142 is set on the projection surface 21, and the light emitted from the light emitting portion is projected into the drawing area 142 ( The driving of the light emitting part is controlled so that the light is irradiated. That is, within the drawing region 142, every time corresponding to one pixel on the projection surface 21 according to the angle of the vertical scanning mirror and the angle of the horizontal scanning mirror (this time also depends on the drawing position, so the angle of the mirror). In general, the light source is modulated and the image is corrected and displayed (pixel density correction).

  However, when viewed from the horizontal direction, the larger the angle (angle) formed by the optical axis of the light emitted from the scan projector 300 toward the projection surface 21 and the projection surface, the greater the distortion correction is required. . For example, as shown in FIG. 27, when projecting an image from the oblique direction in the vertical direction with respect to the projection plane 21, the position farther from the scan projector 300 in the vertical direction is the horizontal direction of one drawing line 141. The length (the horizontal fluctuation width of the light on the projection surface in the light emitting state where light is emitted from the light emitting portion) is increased, thereby increasing the non-drawing area and the time aperture ratio (image drawing). The ratio of the period during which the light source is performed is reduced, the luminance per pixel is lowered, and the light source needs to be modulated at high speed.

As means for solving the above-described problem, a technique has been proposed in which the deflection angle (amplitude) about the rotation center axis of the horizontal scanning mirror is made variable and gradually changed (see, for example, Patent Document 1).
That is, as shown in FIG. 28, in the scan projector 300 of Patent Document 1, when scanning light onto the projection surface 21, the vertical position on the projection surface 21 where the light is scanned is from the scan projector 300. The farther away, the smaller the deflection angle of the horizontal scanning mirror is, and the trapezoidal distortion of the image is prevented.
In addition, since the driving frequency of the horizontal scanning mirror is high, an energy-efficient resonance driving type (using resonance) is usually used as the horizontal scanning mirror.

  However, in the scan projector 300 of Patent Document 1, the magnitude of the drive signal that is a voltage signal or current signal supplied to the horizontal scanning mirror is changed to change the deflection angle of the horizontal scanning mirror. If the magnitude of is changed, the resonance frequency also changes accordingly. As a result, the driving frequency of the mirror for horizontal scanning deviates from the resonance frequency, so that resonance driving cannot be performed, and there is a problem in that it cannot be driven efficiently.

JP 2007-199251 A

  An object of the present invention is to provide an optical scanning device that can prevent trapezoidal distortion of an image while increasing the time aperture ratio and can be driven efficiently.

Such an object is achieved by the present invention described below.
The optical scanning device of the present invention is configured to draw an image by scanning light on a projection surface,
A light emitting portion for emitting light;
Reflecting the light emitted from the light emitting part and having at least one reflecting surface rotatably provided, the light emitted from the light emitting part is directed to the projection surface in a first direction. An optical scanning unit that scans two-dimensionally by scanning in a second direction orthogonal to the first direction at a scanning speed slower than the scanning speed in the first direction;
Control means for controlling the operation of the optical scanning unit,
The optical scanning unit has a scanning mechanism that resonates and drives a reflecting surface that scans in the first direction by being supplied with a drive signal that is a voltage signal or a current signal having a predetermined magnitude and a predetermined frequency. ,
The control means includes changing means for changing the magnitude of the drive signal and the frequency of the drive signal at different timings when scanning in the first direction.

Thereby, it is possible to prevent the trapezoidal distortion of the image while increasing the time aperture ratio, and to drive efficiently.
Further, since the reflection surface that scans in the first direction by changing the magnitude and frequency of the drive signal is resonantly driven, it can be driven efficiently. In particular, since the magnitude of the drive signal and the frequency of the drive signal are changed at different timings, it is possible to reliably resonate the reflecting surface that scans in the first direction.

In the optical scanning device according to the aspect of the invention, in the light emitting state in which light is emitted from the light emitting unit, the fluctuation width of the light on the projection surface in the first direction is the magnitude of the driving signal and the driving signal. Compared with the case where the frequency is constant, the magnitude of the drive signal and the frequency of the drive signal that are aligned along the second direction and cause the reflection surface that scans in the first direction to resonate Having storage means for storing drive signal data including data;
Preferably, the changing unit includes a determining unit that determines the magnitude of the driving signal to be changed and the frequency of the driving signal based on the driving signal data.
Thus, it is possible to reliably resonate the reflecting surface that scans in the first direction while preventing trapezoidal distortion of the image.

In the optical scanning device of the present invention, it has an angle detection means for detecting the angle of the reflecting surface that scans in the first direction,
The changing unit determines a timing for changing one of the magnitude of the driving signal and the frequency of the driving signal and then changing the other based on the detection result of the angle detecting unit and the frequency of the driving signal. It is preferable to be configured.
Thus, it is possible to reliably resonate the reflecting surface that scans in the first direction while preventing trapezoidal distortion of the image.
In the optical scanning device according to the aspect of the invention, it is preferable that the changing unit is configured to change the one when the reflecting surface that scans in the first direction rotates to the maximum.
Thus, it is possible to reliably resonate the reflecting surface that scans in the first direction while preventing trapezoidal distortion of the image.

In the optical scanning device of the present invention, the changing unit includes a deflection angle estimation unit that estimates the deflection angle based on a detection result of the angle detection unit and a frequency of the drive signal,
A determination unit that determines whether or not the estimated value of the deflection angle and the target value of the deflection angle match;
When the estimated value of the deflection angle and the target value of the deflection angle coincide with each other, it is preferable that the other is changed.
Thus, it is possible to reliably resonate the reflecting surface that scans in the first direction while preventing trapezoidal distortion of the image.

In the optical scanning device according to the aspect of the invention, it is preferable that the changing unit is configured not to change the other when the estimated value of the deflection angle and the target value of the deflection angle do not match.
Thereby, the resonance state of the reflecting surface that scans in the first direction can be reliably maintained.
In the optical scanning device according to the aspect of the invention, when the estimated value of the deflection angle and the target value of the deflection angle do not match, the changing unit next changes one of the magnitude of the drive signal and the frequency of the drive signal. In this case, it is preferable to have a correction unit that corrects the one set scheduled value.
Thereby, the trapezoid distortion of an image can be prevented more reliably.

In the optical scanning device according to the aspect of the invention, the changing unit may be configured to change the magnitude of the drive signal first and change the frequency of the drive signal later when increasing the deflection angle. preferable.
Thus, it is possible to reliably resonate the reflecting surface that scans in the first direction while preventing trapezoidal distortion of the image.

In the optical scanning device according to the aspect of the invention, the change unit may be configured to change the frequency of the drive signal first and to change the magnitude of the drive signal later when the deflection angle is decreased. preferable.
Thus, it is possible to reliably resonate the reflecting surface that scans in the first direction while preventing trapezoidal distortion of the image.

In the optical scanning device of the present invention, the changing means changes the magnitude of the drive signal first, changes the frequency of the drive signal later, and changes the frequency of the drive signal first. A second mode in which the magnitude of the drive signal is changed later, and when the deflection angle is increased, the second mode is operated, and when the deflection angle is decreased, the second mode is selected. It is preferable to be configured to operate in this mode.
Thus, it is possible to reliably resonate the reflecting surface that scans in the first direction while preventing trapezoidal distortion of the image.

In the optical scanning device of the present invention, the scanning in the second direction is performed in each of the forward path and the backward path, and the scanning in the first direction is performed in each of the forward path and the backward path of the scanning in the second direction. Is preferably configured to draw.
Thereby, it is possible to prevent the trapezoidal distortion of the image without abruptly changing the deflection angle around the rotation central axis of the reflecting surface that scans in the first direction.

In other words, since the image is drawn by performing the scan in the first direction in each of the forward path and the backward path in the second direction, when switching from the forward path to the backward path in the scan in the second direction, or from the return path to the forward path When switching, it is not necessary to suddenly change the deflection angle of the reflecting surface that scans in the first direction, and thus the deflection angle of the reflecting surface that scans in the first direction can be easily and reliably changed. it can.
Further, since the image is drawn by performing the scanning in the first direction in each of the forward path and the backward path in the second direction, there is no blanking period in the second direction. The ratio of the display period can be reduced. Accordingly, when the image is drawn by performing scanning in the first direction only in the scanning path in the second direction and when the angular velocity (speed) of the reflecting surface scanned in the first direction is the same, only the traveling path is provided. As compared with the case of drawing an image, the number of frames (frame number) per unit time can be increased, and thereby, it is possible to easily cope with a fast movement in a moving image. In other words, when the image is drawn by scanning in the first direction only in the forward path of the second direction and when the number of frames per unit time is the same, the image is drawn only in the forward path As compared with the above, it is possible to reduce the angular velocity of the reflecting surface that scans in the first direction, thereby stably drawing an image.

The optical scanning device of the present invention has temperature detection means for detecting the temperature of the scanning mechanism,
Preferably, the changing unit is configured to change the magnitude of the drive signal and the frequency of the drive signal in consideration of the detection result of the temperature detection unit.
Thereby, the reflective surface scanned in the first direction can be made to resonate more reliably.

The optical scanning device of the present invention has temperature detection means for detecting the temperature of the scanning mechanism,
The storage means stores the drive signal data for each temperature,
It is preferable that the determination unit is configured to determine the magnitude of the drive signal to be changed and the frequency of the drive signal based on the detection result of the temperature detection unit and the data for the drive signal.
Thereby, the reflective surface scanned in the first direction can be made to resonate more reliably.
In the optical scanning device of the present invention, temperature detecting means for detecting the temperature of the scanning mechanism;
It is preferable to have temperature adjusting means for adjusting the temperature of the scanning mechanism to a target temperature based on the detection result of the temperature detecting means.
Thereby, the reflective surface scanned in the first direction can be made to resonate more reliably.

In the optical scanning device according to the aspect of the invention, the scanning mechanism is rotatably provided and has a movable plate having a reflection surface that scans in the first direction, and a support portion that rotatably supports the movable plate; An actuator comprising a connecting portion for connecting the movable plate and the support portion, and a driving means for rotating the movable plate;
The optical scanning unit preferably includes a galvanometer mirror having a reflecting surface that scans in the second direction.
As a result, the reflective surface that scans in the first direction and the reflective surface that scans in the second direction can be driven separately, so that the first The reflecting surface scanning in the direction can be made to resonate.

It is a perspective view which shows 1st Embodiment of the optical scanning device of this invention. It is a figure which shows the optical scanning device shown in FIG. It is a typical perspective view which shows the actuator of the optical scanning device shown in FIG. FIG. 2 is a schematic cross-sectional view showing driving of an actuator of the optical scanning device shown in FIG. 1. It is a figure which shows the galvanometer mirror of the optical scanning device shown in FIG. FIG. 2 is a block diagram illustrating an operation control unit, an optical scanning unit, and a light source unit of the optical scanning device illustrated in FIG. 1. It is a figure for demonstrating operation | movement of the optical scanning device shown in FIG. 1 (a is a side view, b is a front view). 2 is a graph showing a deflection angle (change in deflection angle with time) of a movable plate of an actuator during operation of the optical scanning device shown in FIG. 1. It is a graph which shows the angle (change with time of an angle) of the mirror of a galvanometer mirror in operation | movement of the optical scanning device shown in FIG. It is a figure which shows the structural example of the table (calibration curve) memorize | stored in the calibration curve memory | storage part of the optical scanning device shown in FIG. It is a graph which shows the frequency characteristic of the actuator of the optical scanning device shown in FIG. It is a graph which shows the frequency characteristic of the actuator of the optical scanning device shown in FIG. 2 is a graph showing a drive signal of an actuator and an angle of a movable plate of the optical scanning device shown in FIG. 2 is a graph showing a drive signal of an actuator and an angle of a movable plate of the optical scanning device shown in FIG. It is a figure which shows the modification of the optical scanning device shown in FIG. 1, and its operation | movement (a is a side view, b is a front view). It is a flowchart which shows the control operation | movement at the time of the error processing of the optical scanning device concerning 2nd Embodiment of this invention. It is a flowchart which shows the control operation | movement at the time of the error processing of the optical scanning device concerning 2nd Embodiment of this invention. It is a block diagram of the optical scanning device concerning a 3rd embodiment of the present invention. It is a typical perspective view which shows the actuator of the optical scanning device which concerns on 3rd Embodiment of this invention. It is a block diagram of the optical scanning device concerning a 4th embodiment of the present invention. It is a typical top view showing an actuator with which an optical scanning device concerning a 5th embodiment of the present invention is provided. It is the BB sectional view taken on the line in FIG. It is a block diagram which shows the voltage application means of the drive means with which the actuator shown in FIG. 21 is provided. It is a figure which shows an example of the voltage which generate | occur | produces in the 1st voltage generation part shown in FIG. 23, and a 2nd voltage generation part. It is a figure for demonstrating operation | movement of the optical scanning device which concerns on 5th Embodiment of this invention (a is a side view, b is a front view). It is a figure for demonstrating operation | movement of the conventional scan projector (a is a side view, b is a front view). It is a figure for demonstrating operation | movement of the conventional scan projector (a is a side view, b is a front view). It is a figure for demonstrating operation | movement of the conventional scan projector (a is a side view, b is a front view).

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of an optical scanning device (image forming apparatus) according to the invention will be described with reference to the accompanying drawings. In the present embodiment, the first direction is typically described as “horizontal direction” and the second direction as “vertical direction”.

<First Embodiment>
First, a first embodiment of the optical scanning device of the present invention will be described.
FIG. 1 is a perspective view showing a first embodiment of the optical scanning device of the present invention. FIG. 2 is a diagram showing the optical scanning device shown in FIG. FIG. 3 is a schematic perspective view showing an actuator of the optical scanning device shown in FIG. FIG. 4 is a schematic cross-sectional view showing driving of an actuator of the optical scanning device shown in FIG. FIG. 5 is a diagram showing a galvanometer mirror of the optical scanning device shown in FIG. 6 is a block diagram showing an operation control unit, an optical scanning unit, and a light source unit of the optical scanning device shown in FIG. 7 is a diagram for explaining the operation of the optical scanning device shown in FIG. 1, FIG. 7 (a) is a side view, and FIG. 7 (b) is a front view. FIG. 8 is a graph showing the deflection angle (change in deflection angle over time) of the movable plate of the actuator during operation of the optical scanning device shown in FIG. FIG. 9 is a graph showing the angle of the galvanometer mirror (change in angle over time) during operation of the optical scanning device shown in FIG. FIG. 10 is a diagram illustrating a configuration example of a table (calibration curve) stored in the calibration curve storage unit of the optical scanning device illustrated in FIG. 11 and 12 are graphs showing the frequency characteristics of the actuator of the optical scanning device shown in FIG. FIG. 13 and FIG. 14 are graphs showing the driving signal of the actuator of the optical scanning device shown in FIG. 1 and the angle of the movable plate, respectively. 15A and 15B are diagrams showing a modification of the optical scanning device shown in FIG. 1 and its operation. FIG. 15A is a side view and FIG. 15B is a front view. Hereinafter, for convenience of explanation, the upper side in FIGS. 3, 4, 7, and 15 is referred to as “upper”, the lower side as “lower”, the right side as “right”, and the left side as “left”.

As shown in FIG. 1, the optical scanning device (image forming apparatus) 1 shown in these drawings is an apparatus that is used by being mounted on a support table 2 such as a desk, for example. The optical scanning device 1 uses the surface of the support 2 (the surface on which the optical scanning device 1 is placed) as a projection surface 21, and scans light on the projection surface 21 to form an image (video). It is a device for (drawing) (projecting). That is, the vicinity of the surface of the support base 2 is used as a screen, and a predetermined image such as a still image or a moving image is drawn on the projection surface 21 by scanning the light with the optical scanning device 1. Since the optical scanning device 1 is used by being placed on the projection surface 21 of the support base 2, the positional relationship between the optical scanning device 1 and the drawing area 142 on the projection surface 21 is constant.
As shown in FIG. 2, the optical scanning device 1 includes a light source unit (light emitting unit) 4 that emits light, an optical scanning unit 5 that scans light projected from the light source unit 4 with respect to the projection surface 21, and a light source. An operation control device (control means) 8 that controls the operation (drive) of the unit 4 and the optical scanning unit 5 is provided.
As shown in FIG. 2, the light source unit 4 includes laser light sources 41r, 41g, and 41b for each color, collimator lenses 42r, 42g, and 42b, and dichroic mirrors provided corresponding to the laser light sources 41r, 41g, and 41b for each color. 43r, 43g, 43b.

  As shown in FIG. 6, each color laser light source 41r, 41g, 41b has a drive circuit 410r, 410g, 410b, a red light source 420r, a green light source 420g, and a blue light source 420b, respectively. As shown in FIG. 2, red, green, and blue laser beams RR, GG, and BB are emitted. The laser beams RR, GG, and BB are emitted in a modulated state corresponding to drive signals transmitted from a light source modulation unit 84 (to be described later) of the operation control device 8, and collimator lenses 42r that are collimating optical elements, The beams are collimated by 42g and 42b to form a thin beam.

The dichroic mirrors 43r, 43g, and 43b have characteristics of reflecting the red laser beam RR, the green laser beam GG, and the blue laser beam BB, respectively, and combine the laser beams RR, GG, and BB of the respective colors into one laser beam. (Light) LL is emitted.
A collimator mirror can be used in place of the collimator lenses 42r, 42g, and 42b. In this case as well, a narrow beam of parallel light beams can be formed. Further, when parallel light beams are emitted from the laser light sources 41r, 41g, and 41b of the respective colors, the collimator lenses 42r, 42g, and 42b can be omitted. Further, the laser light sources 41r, 41g, and 41b can be replaced with light sources such as light emitting diodes that generate similar light beams. The order of the laser light sources 41r, 41g, 41b, the collimator lenses 42r, 42g, 42b, and the dichroic mirrors 43r, 43g, 43b in FIG. 2 is merely an example, and the combination of the colors (red indicates the laser light source 41r , Collimator lens 42r, dichroic mirror 43r, green is laser light source 41g, collimator lens 42g, dichroic mirror 43g, blue is laser light source 41b, collimator lens 42b, dichroic mirror 43b) and the order is freely set it can. For example, a combination of blue, red, and green is also possible in the order closer to the optical scanning unit 5.

Next, the optical scanning unit 5 will be described.
The optical scanning unit 5 scans the laser light LL emitted from the light source unit 4 in the horizontal direction (first direction) with respect to the projection surface 21 (horizontal scanning: main scanning) and is slower than the horizontal scanning speed. Two-dimensional scanning is performed by scanning (vertical scanning: sub-scanning) in the vertical direction (second direction orthogonal to the first direction) at the scanning speed. The optical scanning unit 5 includes an actuator (first direction scanning unit) (scanning mechanism) 51 that is a horizontal scanning mirror that scans the projection surface 21 with the laser light LL emitted from the light source unit 4 in the horizontal direction. Angle detecting means (behavior detecting means) 52 for detecting an angle (behavior) of a movable plate 511a (reflecting surface of the light reflecting portion 511e) to be described later of the actuator 51, and the laser light LL emitted from the light source unit 4 on the projection surface 21 On the other hand, an angle for detecting the angle (behavior) of a galvano mirror (second direction scanning unit) 12 that is a vertical scanning mirror that scans in the vertical direction and a mirror 121 (reflection surface of the mirror 121) described later of the galvano mirror 12. And detecting means (behavior detecting means) 13.

As shown in FIG. 3, the actuator 51 is of a so-called resonance driven form (using resonance) and is of a so-called one-degree-of-freedom vibration system, and faces the base 511 and the lower surface of the base 511. And a spacer member 512 provided between the base body 511 and the counter substrate 513.
The base 511 includes a movable plate 511a, a support portion 511b that rotatably supports the movable plate 511a, and a pair of connecting portions 511c and 511d that connect the movable plate 511a and the support portion 511b.

  The movable plate 511a has a substantially rectangular shape in plan view. A light reflecting portion (mirror) 511e having light reflectivity is provided on the upper surface of the movable plate 511a. The surface (upper surface) of the light reflecting portion 511e constitutes a reflecting surface (first reflecting surface) that reflects light. The light reflecting portion 511e is made of a metal film such as Al or Ni, for example. A permanent magnet 514 is provided on the lower surface of the movable plate 511a.

The support portion 511b is provided so as to surround the outer periphery of the movable plate 511a in a plan view of the movable plate 511a. That is, the support portion 511b has a frame shape, and the movable plate 511a is located inside thereof.
The connecting portion 511c connects the movable plate 511a and the support portion 511b on the left side of the movable plate 511a, and the connecting portion 511d connects the movable plate 511a and the support portion 511b on the right side of the movable plate 511a. Yes.

Each of the connecting portions 511c and 511d has a longitudinal shape. Further, each of the connecting portions 511c and 511d can be elastically deformed. The pair of connecting portions 511c and 511d are provided coaxially with each other, and the movable plate 511a supports the shaft (hereinafter referred to as “rotation center axis J”) as a center (rotation center). It rotates with respect to the part 511b.
Such a substrate 511 is made of, for example, silicon as a main material, and a movable plate 511a, a support portion 511b, and connection portions 511c and 511d are integrally formed. As described above, by using silicon as a main material, it is possible to realize excellent rotation characteristics and to exhibit excellent durability. Further, fine processing (processing) is possible, and the actuator 51 can be downsized.

The spacer member 512 has a frame shape, and its upper surface is joined to the lower surface of the base 511. The spacer member 512 is substantially equal to the shape of the support portion 511b in the plan view of the movable plate 511a. Such a spacer member 512 is made of, for example, various glasses, various ceramics, silicon, SiO ₂ or the like.
The method for joining the spacer member 512 and the substrate 511 is not particularly limited. For example, the spacer member 512 may be joined via another member such as an adhesive, or anodic bonding may be used depending on the constituent material of the spacer member 512. May be used.

Similar to the spacer member 512, the counter substrate 513 is made of, for example, various types of glass, silicon, SiO ₂ or the like. A coil 515 is provided on the upper surface of the counter substrate 513 and on a portion facing the movable plate 511a.
The permanent magnet 514 has a plate bar shape and is provided along the lower surface of the movable plate 511a. Such a permanent magnet 514 is magnetized (magnetized) in a direction orthogonal to the rotation center axis (first rotation center axis) J in a plan view of the movable plate 511a. That is, the permanent magnet 514 is provided so that a line segment connecting both poles (S pole and N pole) is orthogonal to the rotation center axis J. As shown in FIG. 4, in the present embodiment, the left side of the rotation center axis J is an N pole, and the right side is an S pole.

The permanent magnet 514 is not particularly limited, and for example, a neodymium magnet, a ferrite magnet, a samarium cobalt magnet, an alnico magnet, or the like can be used.
The coil 515 is provided so as to surround the outer periphery of the permanent magnet 514 in a plan view of the movable plate 511a.
The actuator 51 also has means for supplying (flowing) current to the coil 515, that is, energization means (drive circuit) 516 for supplying a drive signal that is a current signal to the coil 515. The energization means 516 is configured to change (adjust) each condition such as the current value (magnitude) and frequency of the drive signal to be supplied. The energizing unit 516, the coil 515, the permanent magnet 514, and the like constitute a driving unit 517 that rotates the movable plate 511a.
The coil 515 is supplied with a predetermined drive signal from the energizing means 516 under the control of the operation control device 8, and a predetermined current flows.

  For example, when an alternating current is supplied from the energizing means 516 to the coil 515 under the control of the operation control device 8, the alternating current flows through the coil 515 and a magnetic field in the thickness direction of the movable plate 511a (vertical direction in FIG. 4) is generated. In addition, the direction of the magnetic field is periodically switched. That is, a state A in which the vicinity of the upper side of the coil 515 is the S pole and the vicinity of the lower side is an N pole, and a state B in which the vicinity of the upper side of the coil 515 is the N pole and the vicinity of the lower side is an S pole are alternately switched.

In the state A, as shown in FIG. 4A, the right side of the permanent magnet 514 is displaced upward by the repulsive force with the magnetic field generated by energizing the coil 515, and the left side of the permanent magnet 514 is the magnetic field. It is displaced downward by the suction force. Thereby, the movable plate 511a rotates counterclockwise and tilts.
On the contrary, in the state B, as shown in FIG. 4B, the right side of the permanent magnet 514 is displaced downward and the left side of the permanent magnet 514 is displaced upward. As a result, the movable plate 511a rotates clockwise and tilts.

By alternately repeating the state A and the state B, the movable plate 511a rotates (vibrates) around the rotation center axis J while twisting and deforming the connecting portions 511c and 511d. In this case, the energizing means 516 resonates and drives (resonates) the movable plate 511a by supplying a drive signal having a predetermined magnitude and a predetermined frequency, which will be described later, to the coil 515.
Further, by changing the drive signal supplied from the energization means 516 to the coil 515 under the control of the operation control device 8, the vibration about the rotation center axis J of the movable plate 511a (the reflection surface of the light reflecting portion 511e) is changed. The angle (amplitude) can be changed. Therefore, the energizing means 516 and the operation control device 8 constitute the main part of the deflection angle changing means for changing the deflection angle around the rotation center axis J of the movable plate 511a. In this embodiment, the deflection angle changing unit changes the deflection angle according to an angle of a mirror 121 (a reflection surface of the mirror 121) described later of the galvano mirror 12.

  The deflection angle is when the movable plate 511a rotates in a predetermined direction when the initial state of the actuator 51 (the state where no drive signal is supplied to the coil 515) is used as a reference (angle is 0 °). Is the maximum angle (rotation angle) (deflection angle). That is, the deflection angle is an angle formed between the light reflecting portion 511e when the actuator 51 is in the initial state and the light reflecting portion 511e when the movable plate 511a is rotated to the maximum in a predetermined direction.

  The configuration of the actuator 51 is not particularly limited as long as the movable plate 511a can be rotated. For example, the driving method is replaced with electromagnetic driving using the coil 515 and the permanent magnet 514. For example, piezoelectric driving using a piezoelectric element or electrostatic driving using electrostatic attraction may be used. In the case of the piezoelectric drive or electrostatic drive, a voltage signal is used as a drive signal.

  As shown in FIG. 5, the galvanometer mirror 12 has a reflection surface (second reflection surface) that reflects light on the surface, and rotates about a rotation center axis (second rotation center axis) Ja. A mirror 121 provided in a possible manner, and a drive unit 124 having a motor (drive source) 122 for rotating the mirror 121 and a drive circuit 123 for the motor 122 are provided. In the galvano mirror 12, the motor 122 repeats forward rotation and reverse rotation alternately by the drive circuit 123, whereby the mirror 121 rotates (vibrates) around the rotation center axis Ja.

  As shown in FIG. 2, the actuator 51 and the galvanometer mirror 12 are provided so that their rotation center axes J and Ja are orthogonal to each other. By providing the actuator 51 and the galvanometer mirror 12 in this manner, the laser light LL emitted from the light source unit 4 can be scanned two-dimensionally (in two directions orthogonal to each other) on the projection plane 21. Thereby, a two-dimensional image can be drawn on the projection surface 21 with a relatively simple configuration.

  The light emitted from the light source unit 4 is reflected by the reflecting surface of the light reflecting portion 511e of the actuator 51, then reflected by the reflecting surface of the mirror 121 of the galvanometer mirror 12, and projected (irradiated) onto the projection surface 21 of the support base 2. Is done. Then, while rotating the light reflecting portion 511e (simultaneously) and rotating the mirror 121 at an angular velocity slower than the angular velocity (speed), the laser light LL emitted from the light source unit 4 is directed to the projection surface 21. In addition to being scanned in the horizontal direction (simultaneously), it is scanned in the vertical direction at a scanning speed slower than the horizontal scanning speed. Thereby, the laser beam LL emitted from the light source unit 4 is scanned two-dimensionally with respect to the projection surface 21, and an image is drawn on the projection surface 21.

The light emitted from the light source unit 4 may be first reflected by the reflecting surface of the mirror 121 of the galvano mirror 12 and then reflected by the reflecting surface of the light reflecting portion 511e of the actuator 51. . That is, it may be configured such that the vertical scanning is performed first and then the horizontal scanning is performed.
Next, the angle detection means 52 for detecting the angle of the movable plate 511a (the reflection surface of the light reflecting portion 511e) of the actuator 51 will be described.

As shown in FIG. 3, the angle detection means 52 includes a piezoelectric element 521 provided on the connecting portion 511 c of the actuator 51, an electromotive force detection unit 522 that detects an electromotive force generated from the piezoelectric element 521, and an electromotive force detection. And an angle detection unit (behavior detection unit) 523 that obtains (detects) an angle (behavior) of the movable plate 511a based on the detection result of the unit 522.
When the connecting portion 511c is torsionally deformed as the movable plate 511a rotates, the piezoelectric element 521 is deformed accordingly. When the piezoelectric element 521 is deformed from a natural state to which no external force is applied, the piezoelectric element 521 has a property of generating an electromotive force having a magnitude corresponding to the deformation amount. Therefore, the angle detection unit 523 includes the electromotive force detection unit 522. The degree of twist of the connecting portion 511c is obtained on the basis of the magnitude of the electromotive force detected in Step 1, and the angle (rotation angle) of the movable plate 511a (the reflection surface of the light reflecting portion 511e) is determined from the degree of twist. Ask. In addition, the angle detection unit 523 obtains a deflection angle around the rotation center axis J of the movable plate 511a. A signal including information on the angle and deflection angle of the movable plate 511 a is transmitted from the angle detection unit 523 to the operation control device 8.

  The angle of the movable plate 511a to be detected is predetermined by the movable plate 511a when the actuator 51 is in an initial state (a state where no drive signal is supplied to the coil 515) as a reference (angle is 0 °). It is an angle (rotation angle) (deflection angle) when rotating in the direction. That is, the detected angle of the movable plate 511a is an angle formed by the light reflecting portion 511e when the actuator 51 is in the initial state and the light reflecting portion 511e when the movable plate 511a is rotated in a predetermined direction.

Further, the detection of the angle of the movable plate 511a may be performed in real time (continuously) or intermittently. Needless to say, the angle detection means 52 is not limited to the one using the piezoelectric element as in the present embodiment as long as the angle of the movable plate 511a can be detected.
Next, the angle detection means 13 for detecting the angle of the mirror 121 (the reflecting surface of the mirror 121) of the galvanometer mirror 12 will be described.

As shown in FIG. 5, the angle detection means 13 receives an encoder 131 provided in the galvano mirror 12 and a signal sent from the encoder 131, and the angle (behavior) of the mirror 121 based on the information included in the signal. And an angle detection unit (behavior detection unit) 132 for (detecting).
When the mirror 121 is rotated by the operation of the driving unit 124, a signal is transmitted from the encoder 131 to the angle detection unit 132 accordingly. The angle detection unit 132 obtains the angle (rotation angle) of the mirror 121 based on information included in the signal transmitted from the encoder 131. A signal including information on the angle of the mirror 121 is transmitted from the angle detection unit 132 to the operation control device 8.

The angle of the mirror 121 to be detected may be set to an angle when any state of the galvano mirror 12 is used as a reference (angle is 0 °).
The angle of the mirror 121 may be detected in real time (continuously) or intermittently. Needless to say, the angle detection means 13 is not limited to the one using the encoder as in the present embodiment as long as the angle of the mirror 121 can be detected.

Next, the operation control device 8 will be described.
As shown in FIG. 6, the operation control device 8 includes a video data storage unit (video data storage unit) 81 that stores video data (image data) used when drawing an image, a video data calculation unit 82, A drawing timing generation unit 83, a light source modulation unit (light modulation unit) 84, a deflection angle calculation unit (amplitude calculation unit) 85, an angle instruction unit 86, and a calibration curve storage unit (a calibration curve storage unit) that stores a calibration curve 87). The deflection angle calculation unit 85 includes a comparison calculation unit 851 and a drive signal instruction unit 852. The deflection angle calculation unit 85 includes a function of a changing unit including a determination unit, a determination unit, a deflection angle estimation unit, and the like. That is, the comparison calculation unit 851 has functions of a deflection angle estimation unit and a determination unit, and the drive signal instruction unit 852 has a function of a determination unit.

  Here, the optical scanning device 1 performs scanning in the vertical direction (second direction) (hereinafter also simply referred to as “vertical scanning”) in each of the forward path and the backward path, and in each of the forward path and the backward path of the vertical scanning, An image is drawn by scanning in the horizontal direction (first direction) (hereinafter also simply referred to as “horizontal scanning”) in each of the forward path and the backward path. Then, the optical scanning device 1 performs laser scanning on the projection surface 21 in a light emitting state in which laser light (light) LL is emitted from the light source unit 4 (hereinafter also simply referred to as “light emitting state”) when performing horizontal scanning. The horizontal deflection width of the light LL (hereinafter, also simply referred to as “laser beam (light) LL deflection width”) is a deflection angle (hereinafter simply referred to as “movable plate”) about the rotation center axis J of the movable plate 511a. Compared to the case where the change is not made ”(compared to the case where the magnitude of the drive signal and the frequency of the drive signal are made constant), they are aligned along the vertical direction and the movable plate 511a. Is configured so as to change the deflection angle of the movable plate 511a so as to resonate. In particular, it is preferable that the deflection angle of the movable plate 511a is changed so that the deflection width of the laser beam LL is constant along the vertical direction in the light emission state and the movable plate 511a resonates. . Thereby, it is possible to prevent the trapezoidal distortion of the image while increasing the time aperture ratio, and to drive efficiently. In the present embodiment, a case will be described in which the deflection angle of the movable plate 511a is changed so that the deflection width is constant along the vertical direction and the movable plate 511a resonates.

  The deflection width is the position of the laser beam LL on the projection surface 21 when the movable plate 511a rotates to a maximum angle in a predetermined direction (clockwise or counterclockwise) in the light emitting state, Subsequently, the distance (interval) in the horizontal direction from the position of the laser beam LL on the projection surface 21 when the movable plate 511a rotates to the maximum angle in the opposite direction. That is, the fluctuation width is a locus of the laser light LL on the projection surface 21 when the laser light LL is two-dimensionally scanned on the projection surface 21 in a light emitting state as shown in FIG. Each of the drawing lines (scanning lines) 141 has a horizontal length.

  As shown in FIG. 7, the plurality of drawing lines 141 are arranged in a zigzag manner. Of each drawing line 141, the left end portion and the right end portion each have a small angular velocity (speed) of the mirror 121 and are not suitable for drawing. Therefore, except for the left end portion and the right end portion, A drawing area 142, which is an area for drawing an image, is set. The drawing area 142 is set to form, for example, a rectangle (including a square).

  When the deflection angle of the movable plate 511a is constant, the deflection width of the laser beam LL in the light emission state changes according to the angle of the mirror 121, and the vertical direction on the projection surface 21 on which the laser beam LL is scanned. The position becomes longer as the position (the position in the vertical direction of the drawing line 141) is farther from the optical scanning device 1. Therefore, in this optical scanning device 1, the deflection angle of the movable plate 511 a is changed according to the angle of the mirror 121. That is, as the vertical position (the vertical position of the drawing line 141) on the projection surface 21 scanned with the laser light LL is farther from the optical scanning device 1, the deflection angle of the movable plate 511a is reduced to reduce the light beam. The fluctuation width of the laser beam LL in the emission state is made constant along the vertical direction.

Specifically, when the vertical position on the projection surface 21 on which the laser beam LL is scanned approaches the optical scanning device 1 (in the case of vertical scanning from far to near), the deflection angle of the movable plate 511a is gradually increased. Thus, the fluctuation width of the laser light LL in the light emission state is made constant along the vertical direction.
On the other hand, when the vertical position on the projection surface 21 on which the laser beam LL is scanned moves away from the optical scanning device 1 (in the case of vertical scanning from near to far), the deflection angle of the movable plate 511a is gradually decreased. The fluctuation width of the laser beam LL in the light emission state is made constant along the vertical direction.

In changing the deflection angle of the movable plate 511a, the deflection angle calculation unit 85 changes the magnitude (amplitude) and frequency of the drive signal at different timings. That is, the change in the magnitude of the drive signal and the change in the frequency of the drive signal are performed with a time difference. Thereby, the movable plate 511a can be reliably resonated and driven efficiently.
Note that when the swing angle of the movable plate 511a is gradually increased, the magnitude and frequency of the drive signal are gradually increased, and when the swing angle of the movable plate 511a is gradually decreased, the magnitude of the drive signal is increased. Gradually decrease the length and frequency respectively.

In addition, the deflection angle calculation unit 85 changes the magnitude of the drive signal first, changes the frequency of the drive signal later, and changes the frequency of the drive signal first, thereby changing the magnitude of the drive signal. And a second mode to be changed later.
When the deflection angle of the movable plate 511a is gradually increased to make the deflection width of the laser beam LL constant in the vertical direction, the deflection angle calculation unit 85 operates in the first mode. First, the magnitude of the drive signal is changed, and then the frequency of the drive signal is changed. The reason is as follows.

  First, when increasing the deflection angle of the movable plate 511a, the magnitude and frequency of the drive signal are increased. Further, the frequency characteristics of the actuator 51 are as shown in FIG. 11, and the swing angle of the movable plate 511a decreases rapidly from the vicinity where the drive frequency of the actuator 51 exceeds the resonance frequency f0. For this reason, when the drive frequency is set near the resonance frequency f0 and the movable plate 511a is resonating, the magnitude and frequency of the drive signal are increased simultaneously or the frequency of the drive signal is increased first. In some cases, the drive frequency of the actuator 51 becomes higher than the resonance frequency f0, and the movable plate 511a does not resonate or stops. However, in this optical scanning device 1, since the magnitude of the drive signal is first increased and then the frequency of the drive signal is increased, the above-described problem can be prevented and the movable plate 511a is reliably resonated. be able to.

On the other hand, when the deflection angle of the movable plate 511a is gradually decreased so that the deflection width of the laser beam LL in the light emission state is constant along the vertical direction, the deflection angle calculation unit 85 is in the second mode. In operation, the frequency of the drive signal is changed first, and the magnitude of the drive signal is changed later. The reason is as follows.
First, when reducing the deflection angle of the movable plate 511a, the magnitude and frequency of the drive signal are reduced. Further, the frequency characteristic of the actuator 51 changes as shown by a broken line from the solid line in FIG. 12 when the magnitude of the drive signal is decreased. For this reason, when the drive frequency is set near the resonance frequency f0 and the movable plate 511a is resonating, the magnitude and frequency of the drive signal are simultaneously reduced, or the magnitude of the drive signal is reduced first. Then, the resonance frequency of the actuator 51 decreases from f0 to f0 ′, the drive frequency of the actuator 51 becomes higher than the resonance frequency f0 ′, and the movable plate 511a may not resonate or stop. However, in this optical scanning device 1, since the frequency of the drive signal is reduced first and the magnitude of the drive signal is reduced later, the above-mentioned problem can be prevented and the movable plate 511a is reliably resonated. be able to.

Here, the time difference (time interval) between the change in the magnitude of the drive signal and the change in the frequency is preferably 0.5% or more of the cycle of the drive signal, and is 0.5% or more and 100% or less. More preferably, it is 1% or more and 80% or less. Specifically, the magnitude of the time difference is preferably 0.1 μsec or more, more preferably 0.1 μsec or more and 150 μsec or less, and 0.3 μsec or more and 100 μsec or less. Is more preferable.
If the time difference is smaller than the lower limit value, the movable plate 511a may not resonate or stop depending on other conditions. If the time difference is larger than the upper limit value, the effect of preventing trapezoidal distortion of the image may be reduced.

  In the calibration curve storage unit 87 which is a storage means, the fluctuation width of the laser light LL is constant along the vertical direction in the light emission state (the fluctuation width of the laser light LL in the light emission state is the magnitude of the drive signal and the drive). Compared with the case where the frequency of the signal is constant, they are aligned along the vertical direction), and the vertical position on the projection surface 21 of the laser light LL that scans the projection surface 21 satisfies the condition that the movable plate 511a resonates. Tables and arithmetic expressions indicating the relationship between (the position in the vertical direction of the drawing line 141), the magnitude of the drive signal of the actuator 51, the frequency of the drive signal, and the target value (target shake angle) of the swing angle of the movable plate 511a. A calibration curve such as (function) is stored (stored). That is, the calibration curve storage unit 87 stores the magnitude of the drive signal corresponding to the vertical position on the projection plane 21 of the laser beam LL scanned on the projection plane 21, the frequency of the drive signal, and the deflection angle of the movable plate 511a. Drive signal data including data such as target values is stored. When drawing an image, the calibration curve is used to drive the magnitude of the drive signal, the frequency of the drive signal, and the frequency of the movable plate 511a corresponding to the vertical position on the projection plane 21 of the laser light LL that scans the projection plane 21. Each target value of the deflection angle is acquired. The calibration curve can be obtained by calculation or experiment, and is stored in the calibration curve storage unit 87 in advance. The optical scanning device 1 is used by being placed on the projection surface 21 of the support base 2, and the positional relationship between the optical scanning device 1 and the drawing area 142 on the projection surface 21 is constant, so that one pattern A calibration curve can be created and stored.

  FIG. 10 shows a table as a configuration example of the calibration curve. In this table, on the projection surface 21 of the laser beam LL that scans the projection surface 21, the fluctuation width of the laser beam LL is constant along the vertical direction in the light emitting state, and the condition that the movable plate 511 a resonates is satisfied. The relationship between the position in the vertical direction, the magnitude of the drive signal of the actuator 51, the frequency of the drive signal, and the target value of the deflection angle of the movable plate 511a is shown.

That is, in the table shown in FIG. 10, the deflection angle of the movable plate 511a is set according to each position in the vertical direction on the projection surface 21 of the laser light LL that scans the projection surface 21 so as to satisfy the above condition. The target value, the frequency of the drive signal, and the magnitude of the drive signal are defined.
For example, at a predetermined position in the vertical direction, the target value of the deflection angle of the movable plate 511a is defined as “10 °”, the frequency of the drive signal is “8000 Hz”, and the magnitude of the drive signal is “20 mA”.

At another predetermined position in the vertical direction, the target value of the deflection angle of the movable plate 511a is “10.1 °”, the frequency of the drive signal is “8001 Hz”, and the magnitude of the drive signal is “20.3 mA”. It is prescribed.
Further, at another predetermined position in the vertical direction, the target value of the deflection angle of the movable plate 511a is “10.2 °”, the frequency of the drive signal is “8002 Hz”, and the magnitude of the drive signal is “20.4 mA”. It is prescribed.

Here, the timing for changing one of the magnitude of the driving signal and the frequency of the driving signal (the one to be changed first), and the timing for changing the other (the one to be changed later) after changing one of them, It is not specifically limited, It can set suitably according to various conditions.
In this embodiment, the timing for changing the one is when the movable plate 511a is rotated to the maximum in a predetermined direction.

  The timing for changing the other is determined based on the detection result of the angle detection means 52 and the frequency of the drive signal. That is, based on the detection result of the angle detection means 52 and the frequency of the drive signal, the deflection angle of the movable plate 511a is estimated, and when the estimated value of the deflection angle and the target value of the deflection angle match, It is time to change the other. If the estimated value of the deflection angle does not match the target value of the deflection angle, the other change is not performed. The estimation of the deflection angle of the movable plate 511a and the determination of whether or not the estimated value of the deflection angle and the target value of the deflection angle coincide with each other are performed by the comparison calculation unit 851 of the deflection angle calculation unit 85, respectively.

The frequency (period) of the drive signal used for estimation of the deflection angle is the frequency after the change when the frequency of the drive signal is changed first, and the frequency of the drive signal is changed when the frequency of the drive signal is changed later. The frequency to be changed.
In addition, the drive signal may be changed for each line or for each of a plurality of lines. In the following, a case where the drive signal is typically changed for every two lines (every period of the drive signal) will be described. To do.

That is detected by the angle detecting means 52 at time t when measured from the time you change one of the magnitude and frequency of the target value of the deflection angle of the movable plate 511a theta _n, drive signal (How to change earlier) Θ (t), the difference between the angle detected by the angle detection means 52 at time t and the angle detected by the angle detection means 52 immediately before it is Δθ (t), and the frequency of the drive signal is f When the period of the drive signal is T and the following formula 1 or formula 2 is satisfied, the timing of changing the other of the drive signal magnitude and frequency (the one to be changed later) is changed. Note that, as described above, f and T are the frequency and period after the change when the frequency of the drive signal is changed first, and are scheduled to be changed when the frequency of the drive signal is changed later. Frequency and period.

θ _n − {| Δθ (t) | / 2πf · | cos (2πft) |} = 0
(However, 0 ≦ t <T / 8, 3T / 8 ≦ t <5T / 8, 7T / 8 ≦ t <T) (Formula 1)
θ _n − {θ (t) / | sin (2πft) |} = 0
(However, T / 8 ≦ t <3T / 8, 5T / 8 ≦ t <7T / 8) (Formula 2)
The value of “| Δθ (t) | / 2πf · | cos (2πft) |” in Equation 1 and the value of “θ (t) / | sin (2πft) |” in Equation 2 are The estimated value of the deflection angle of the movable plate 511a after the change, and satisfying Equation 1 or Equation 2 is synonymous with the agreement between the estimated value of the deflection angle and the target value of the deflection angle. That is, when Expression 1 or Expression 2 is satisfied, it means that the deflection angle of the movable plate 511a becomes equal to the target value after the other change.

Hereinafter, specific examples will be described with reference to FIGS. 13 and 14.
First, when the deflection angle of the movable plate 511a is gradually increased so that the deflection width of the laser beam LL in the light emission state is constant along the vertical direction, the first mode is operated and the drive is performed first. The magnitude (amplitude) of the signal is changed, and then the frequency of the drive signal is changed. That is, as shown in FIG. 13, first, when the angle of the movable plate 511a is maximized in a predetermined direction, the amplitude (current value) of the current signal (drive signal) is changed from I1 to I2. Note that the amplitude of the current signal may be changed when the angle of the movable plate 511a becomes maximum in the opposite direction.

Next, from the time when the amplitude of the current signal is changed from I1 to I2, angle detection is performed at any time by the angle detection means 52 to determine whether or not Expression 1 or Expression 2 is satisfied, and Expression 1 or Expression 2 is satisfied. And the frequency of the current signal is changed. In addition, when neither Equation 1 nor Equation 2 is satisfied, the current value is maintained for the frequency.
Next, similarly, when the angle of the movable plate 511a becomes maximum in a predetermined direction, the amplitude of the current signal is changed from I2 to I3. After that, angle detection is performed at any time by the angle detection means 52 to determine whether or not Expression 1 or Expression 2 is satisfied. When Expression 1 or Expression 2 is satisfied, the frequency is changed.

Similarly, when the angle of the movable plate 511a is maximized in a predetermined direction, the amplitude of the current signal is changed from I3 to I4. After that, angle detection is performed at any time by the angle detection means 52 to determine whether or not Expression 1 or Expression 2 is satisfied. When Expression 1 or Expression 2 is satisfied, the frequency is changed. Hereinafter, since it is similar, description is abbreviate | omitted.
In addition, when the deflection angle of the movable plate 511a is gradually decreased to make the deflection width of the laser beam LL constant in the vertical direction in the light emission state, the second mode is operated first. The frequency of the signal is changed, and the magnitude (amplitude) of the drive signal is changed later. That is, as shown in FIG. 14, first, when the angle of the movable plate 511a is maximized in a predetermined direction, the frequency of the current signal (drive signal) is changed from f1 to f2. In this case as well, the frequency of the current signal may be changed when the angle of the movable plate 511a reaches the maximum in the opposite direction.

Next, from the time when the frequency of the current signal is changed from f1 to f2, the angle detection unit 52 performs angle detection at any time to determine whether or not Expression 1 or Expression 2 is satisfied, and Expression 1 or Expression 2 is satisfied. Then, the amplitude (current value) of the current signal is changed. In addition, when neither Equation 1 nor Equation 2 is satisfied, the current value is maintained for the amplitude.
Next, similarly, when the angle of the movable plate 511a is maximized in a predetermined direction, the frequency of the current signal is changed from f2 to f3. Then, after that, angle detection is performed by the angle detection means 52 at any time to determine whether or not Expression 1 or Expression 2 is satisfied. If Expression 1 or Expression 2 is satisfied, the amplitude of the current signal is changed.

Similarly, when the angle of the movable plate 511a is maximized in a predetermined direction, the frequency of the current signal is changed from f3 to f4. Then, after that, angle detection is performed by the angle detection means 52 at any time to determine whether or not Expression 1 or Expression 2 is satisfied. If Expression 1 or Expression 2 is satisfied, the amplitude of the current signal is changed. Hereinafter, since it is the same, description is abbreviate | omitted.
Further, in the optical scanning device 1, in the drawing region 142, the vertical spacing between the adjacent drawing lines 141 is constant for each odd-numbered drawing line 141 from the upper side. With respect to the drawing lines 141, it is preferable to adjust the angle and angular velocity of the mirror 121 so that the vertical spacing between adjacent drawing lines 141 is constant. Thereby, the distortion of the image in the vertical direction can be prevented.

  In the present embodiment, for example, at the left end and the right end of the drawing area 142 at the start of drawing of each drawing line 141, the vertical spacing between adjacent drawing lines 141 is constant. The angle of the mirror 121 is adjusted, and the angular velocity of the mirror 121 is set to a predetermined value. That is, for each drawing line 141, the angle of the mirror 121 is adjusted so that the vertical interval between adjacent drawing start points is constant, and the angular velocity of the mirror 121 is set to a constant value for each drawing line 141. . Note that the angular velocity of the mirror 121 is set smaller as the vertical position of the drawing line 141 is farther from the optical scanning device 1. Thereby, it is possible to prevent distortion of the image in the vertical direction with relatively simple control.

Next, the operation (action) of the optical scanning device 1 when drawing an image on the projection surface 21 will be described.
First, video data is input to the optical scanning device 1. The input video data is temporarily stored in the video data storage unit 81, read from the video data storage unit 81, and an image is drawn using the video data. In this case, the drawing of the image may be started after all of the video data is stored in the video data storage unit 81, and after a part of the video data is stored in the video data storage unit 81, Drawing may be started, and the subsequent video data may be stored in the video data storage unit 81 in parallel with the drawing of the image.

  When drawing an image after a part of the video data is stored in the video data storage unit 81, first, at least one frame, preferably two frames or more and all frames or less (for example, two frames). ) Is stored in the video data storage unit 81, and then image drawing is started. This is because the optical scanning device 1 performs horizontal scanning in each of the forward and backward passes of vertical scanning to draw an image (hereinafter also simply referred to as “reciprocating drawing in the vertical direction”). The drawing order of the video data from the video data storage unit 81 is reversed between when the image is drawn in the scanning forward path and when the image is drawn in the vertical scanning backward path, so that the image drawing is performed in the vertical scanning backward path. This is because at least one frame of video data used for drawing an image on the return path needs to be stored in the video data storage unit 81 in order to read the video data from the opposite side when starting the video.

The drawing timing generation unit 83 generates drawing timing information and drawing line information, respectively. The drawing timing information is sent to the video data calculation unit 82, and the drawing line information is sent to the deflection angle calculation unit 85.
The drawing timing information includes drawing timing information and the like. Further, the drawing line information includes information on the position (angle of the mirror 121) in the vertical direction of the drawing line 141 on which drawing is performed. Note that the position of any part of the drawing line 141 may be set as the vertical position of the drawing line 141, and examples include the left end, the right end, and the center.

Based on the drawing timing information input from the drawing timing generation unit 83, the video data calculation unit 82 reads the video data corresponding to the pixel to be drawn from the video data storage unit 81, performs various correction calculations, and the like. The luminance data of each color is sent to the light source modulator 84.
The light source modulation unit 84 modulates the light sources 420r, 420g, and 420b via the drive circuits 410r, 410g, and 410b based on the luminance data of each color input from the video data calculation unit 82. That is, the light sources 420r, 420g, and 420b are turned on / off, the output is adjusted (increased / decreased), and the like.

  The angle detection means 52 on the actuator 51 side detects the angle and swing angle of the movable plate 511a, and uses the angle and swing angle information (angle information of the movable plate 511a) as the drawing timing generation unit 83 of the operation control device 8 and This is sent to the deflection angle calculation unit 85. Further, the angle detection means 13 on the galvano mirror 12 side detects the angle of the mirror 121 and sends the angle information (angle information of the mirror 121) to the angle instruction unit 86 of the operation control device 8.

  When the drawing of the current drawing line 141 is completed, the drawing timing generation unit 83 is synchronized with the time when the laser beam LL is applied to the drawing start point of the drawing line 141 to be drawn next on the angle instruction unit 86. Target angle information (angle instruction) indicating the target angle of the mirror 121 is sent out. The target angle of the mirror 121 is set so that the vertical interval between adjacent drawing start points is constant. The angle instructing unit 86 compares the angle of the mirror 121 detected by the angle detecting unit 13 with the target angle of the mirror 121 and performs correction so that the difference becomes 0, thereby driving the galvano mirror 12. Drive data is sent to 124.

The driving unit 124 drives the motor 122 based on the driving data. Accordingly, when the drawing start point is irradiated with the laser beam LL, the angle of the mirror 121 becomes the target angle.
In this embodiment, in each drawing line 141, the angular velocity of the mirror 121 may be constant from the drawing start point to the drawing end point, and the vertical scanning speed of the laser beam LL may be constant. The angular velocity may be gradually changed, and the scanning speed in the vertical direction of the laser beam LL may be gradually changed.

Further, the drawing timing generation unit 83 sends drawing line information, that is, information on the position of the drawing line 141 in the vertical direction to be drawn next, to the deflection angle calculation unit 85.
The deflection angle calculation unit 85 uses the calibration curve read from the calibration curve storage unit 87, and based on the vertical position information of the drawing line 141 to be drawn next input from the drawing timing generation unit 83. Next, the target value of the deflection angle of the movable plate 511a in the drawing line 141 for drawing, the magnitude of the drive signal of the actuator 51, and the frequency of the drive signal are acquired. Then, the drive signal instruction unit 852 of the deflection angle calculation unit 85 sends drive data (data indicating the magnitude and frequency of the drive signal) to the drive unit 517 of the actuator 51.

Based on the drive data, the drive means 517 supplies a corresponding drive signal to the coil 515, passes a current of a predetermined magnitude and a predetermined frequency, generates a predetermined magnetic field, and resonates the movable plate 511a.
Here, as described above, the magnitude and frequency of the drive signal are changed at different timings, but here, typically, the magnitude of the drive signal is changed first, and then the frequency of the drive signal is changed later. The case of changing is described.

  First, the deflection angle calculation unit 85 changes the magnitude of the drive signal when the movable plate 511a rotates to the maximum in a predetermined direction. That is, the drive signal instruction unit 852 reads the magnitude of the corresponding drive signal from the table stored in the calibration curve storage unit 87 based on the information on the position in the vertical direction of the drawing line 141 to be drawn next. The magnitude of the drive signal to be changed is determined as the magnitude of the read drive signal. Then, the drive signal instruction unit 852 sends drive data indicating the magnitude of the read drive signal to the drive unit 517. The drive means 517 changes the magnitude of the drive signal supplied to the coil 515 based on the drive data.

  Further, the comparison calculation unit 851 determines whether or not Expression 1 or Expression 2 is satisfied based on the angle detected by the angle detection unit 52 from the time when the magnitude of the drive signal is changed. And if Formula 1 or Formula 2 is satisfy | filled, the deflection angle calculating part 85 will change the frequency of a drive signal. That is, the drive signal instruction unit 852 reads the frequency of the corresponding drive signal from the table stored in the calibration curve storage unit 87 based on the information on the vertical position of the drawing line 141, and changes the drive signal. Is determined as the frequency of the read drive signal. Then, the drive signal instruction unit 852 sends drive data indicating the frequency of the read drive signal to the drive unit 517. The drive means 517 changes the frequency of the drive signal supplied to the coil 515 based on the drive data.

Similarly, thereafter, the deflection angle calculation unit 85 changes the magnitude of the drive signal when the movable plate 511a rotates to the maximum in the same direction as described above. Change the frequency of the signal.
In the case where the frequency of the drive signal is changed first and the magnitude of the drive signal is changed later, the order of changing the frequency and the order of changing the magnitude are only the reverse of the above. The description is omitted.

In this way, while changing the swing angle of the movable plate 511a so that the swing angle of the movable plate 511a becomes the target swing angle and the movable plate 511a resonates, The laser beam LL is sequentially scanned to draw an image.
In addition, the drawing timing generation unit 83 manages whether a frame to be drawn is an odd frame (odd number frame) or an even number frame (even number frame). The moving direction (moving direction) and the reading order of the video data from the video data storage unit 81 are determined. That is, the video data reading order is reversed between when an image is drawn in an odd frame (vertical scanning forward path) and when an image is drawn in an even frame (vertical scanning backward path).

Further, the laser beam LL is scanned on the same line on the projection surface 21 in the odd frame and the even frame. That is, the laser beam LL is scanned so that each drawing line 141 of the odd frame matches each drawing line 141 of the even frame.
Specifically, for example, as shown in FIG. 7, for the first frame (odd-numbered frame), the drawing starts from the upper left, draws to the lower right zigzag, and the second frame (even-numbered frame) For the frame), the rotation direction of the mirror 121 is reversed, and drawing is performed from the lower right to the upper left in the opposite direction. Thereafter, similarly, the odd-numbered frame is drawn from the upper left to the lower right, and the even-numbered frame is drawn from the lower right to the upper left.

In this embodiment, the vertical scanning forward path is an odd frame and the vertical scanning backward path is an even frame. However, the present invention is not limited to this, and the vertical scanning backward path is an odd frame. The scanning forward path may be an even frame.
In the present embodiment, the drawing start position for the first frame is at the upper left, but is not limited thereto, and may be, for example, the upper right, the lower left, the lower right, or the like.
Further, the laser beam LL may be scanned on different lines on the projection surface 21 in the odd-numbered frame and the even-numbered frame.
Here, the change with time of the deflection angle of the movable plate 511a and the change with time of the angle of the mirror 121 during the drawing of the image are as follows.

In the horizontal scanning, as shown in FIG. 8, the swing angle of the movable plate 511a gradually increases from the minimum swing angle, reaches the maximum swing angle, gradually decreases, reaches the minimum swing angle, and then again. The operation is gradually increased, and thereafter the operation is repeated in the same manner.
Thus, in this optical scanning device 1, the swing angle of the movable plate 511a does not change abruptly. Therefore, the swing angle of the movable plate 511a of the actuator 51 configured to operate using resonance is easily and reliably changed. be able to.

In the vertical scanning, as shown in FIG. 9, a display period (drawing period) in which an image is drawn in an odd frame (vertical scanning forward path) and an image in an even frame (vertical scanning backward path). A non-display period (non-drawing period) in which an image is not drawn is provided between a display period in which drawing is performed. In this display period, each timing such as a timing for starting drawing of the next frame can be adjusted.
Since the image is drawn both in the forward and backward passes of the scanning in the vertical direction, that is, when the mirror 121 is rotated in a predetermined direction and when it is rotated in the opposite direction, the conventional method is used. A vertical blanking period becomes unnecessary, and the non-display period can be shortened. Thereby, a time aperture ratio (ratio of the period which draws an image) can be made high.

In other words, the vertical non-display period in one frame can be shortened by reciprocatingly drawing, thereby increasing the vertical time aperture ratio and drawing an image by performing horizontal scanning only in the forward path of vertical scanning. When the angular velocity (velocity) of the movable plate 511a is the same as the case, the number of frames (frame number) per unit time can be increased compared to the case where an image is drawn only on the forward path. It can easily cope with movement. In other words, when the image is drawn by performing horizontal scanning only in the forward path of the vertical scanning and when the number of frames per unit time is the same, the angular velocity of the movable plate 511a is larger than when the image is drawn only in the forward path. Can be made smaller, whereby an image can be stably drawn. In the above case, when the angular velocity of the movable plate 511a is not changed, drawing with higher vertical resolution is possible.
As described above, according to the optical scanning device 1, it is possible to prevent the trapezoidal distortion of the image without increasing the deflection angle of the movable plate 511a while increasing the time aperture ratio. It can be driven efficiently.

Next, a modified example will be described based on FIG.
In the optical scanning device 1 shown in FIG. 15, the fluctuation width of the laser light LL is not constant along the vertical direction in the light emission state, but the fluctuation width of the laser light LL in the light emission state is that of the movable plate 511a. Compared to the case where the deflection angle is not changed (compared to the case where the magnitude of the drive signal and the frequency of the drive signal are made constant), they are aligned along the vertical direction and the movable plate 511a resonates. The swing angle of the movable plate 511a is changed. As a result, the width on the upper side of the drawable area 143 where the image can be drawn decreases, the shape of the drawable area 143 approaches a rectangle (including a square), and the non-drawn area can be reduced.
In this optical scanning device 1, a rectangular drawing area 142 is set on the projection surface 21, that is, in the drawable area 143, and the laser light LL emitted from the light source unit 4 is projected (irradiated) into the drawing area 142. Thus, the drive of the light source unit 4 is controlled. Thereby, the trapezoid distortion of an image can be prevented.

Second Embodiment
Next, a second embodiment of the optical scanning device of the present invention will be described.
FIG. 16 and FIG. 17 are flowcharts showing control operations in error processing of the optical scanning device according to the second embodiment of the present invention.
Hereinafter, the optical scanning device according to the second embodiment will be described focusing on the differences from the first embodiment described above, and description of similar matters will be omitted.

In the optical scanning device 1 according to the second embodiment, if neither of the formula 1 and the formula 2 is satisfied, that is, if the estimated value of the deflection angle of the movable plate 511a does not match the target value of the deflection angle, an error occurs. It is configured to perform processing. The deflection angle calculation unit 85 includes a function of changing means including a determination unit, a determination unit, a deflection angle estimation unit, a correction unit, and the like.
First, error processing when operating in the first mode in which the magnitude of the drive signal is changed first and the frequency of the drive signal is changed later will be described.

Note that the target value of the current deflection angle of the movable plate 511a is “θ _n ”, and the current value that is the current amplitude of the current signal (driving signal) is set to “I (θ _n )”. It is assumed. Further, as described above, whether or not Expression 1 or Expression 2 is satisfied is determined until drawing for two horizontal lines is completed, and only when the expression is satisfied, the frequency of the current signal is changed.
As shown in FIG. 16, first, when the deflection angle calculation unit 85 of the optical scanning device 1 finishes drawing for two horizontal lines (step S101), in the current signal change this time, It is determined whether Equation 2 is satisfied and the frequency of the current signal has been changed (step S102).

When the frequency of the current signal has been changed, the current value I (θ _{n + 1} ), which is the amplitude to be set next to the current signal, is stored in the calibration curve storage unit 87 when the current value is changed next time. For example, it is obtained from a table (step S103). Then, the current value is changed (set) to the current value I (θ _{n + 1} ) scheduled to be set (step S104). That is, the current value I (θ _{n + 1} ) is not corrected.

On the other hand, if the frequency of the current signal has not been changed, error processing is executed. That is, in the error process, first, a difference θd between the target value θ _n of the current deflection angle of the movable plate 511a and the estimated value of the current deflection angle is obtained (step S105). Then, a difference current value Id that is an amplitude (amplitude increase) of the current signal corresponding to the difference θd is obtained (step S106), and the next set current value I (( θ _{n + 1} ) is corrected. That is, the difference current value Id is added to the current value I (θ _{n + 1} ).

The differential current value Id is obtained by linear interpolation based on the current value I (θ _n ) of the current signal and the current value I (θ _n−1 ) that is the previous amplitude of the current signal. Specifically, the current value I (θ _n ) of the current signal, the previous current value I (θ _n−1 ), the target value θ _n of the current deflection angle, and the previous deflection By substituting the target value θ _{n−1 of the} angle into the following formula 3, a differential current value Id is obtained.
Id = θd · {I (θ _n ) −I (θ _n−1 )} / (θ _n −θ _n−1 ) (Equation 3)

Next, when the current value is changed, the obtained differential current value Id is added to the current value I (θ _{n + 1} ) to be set, and the current value is added (corrected value) “I (θ _{n + 1} )”. It is changed (set) to “+ Id” (step S107). Thereby, the trapezoid distortion of an image can be prevented more reliably.
In addition to I (θ _{n + 1} ), θ _n−1 , θ _n , θ _{n + 1} , I (θ _n−1 ), and I (θ _n ) are also stored in the calibration curve storage unit 87. For example, it can be obtained from a table.

Next, error processing when operating in the second mode in which the frequency of the drive signal is changed first and the magnitude of the drive signal is changed later will be described.
It is assumed that the target value of the current deflection angle of the movable plate 511a is “θ _n ” and the current frequency of the current signal (drive signal) is set to “f (θ _n )”. Further, as described above, it is determined whether or not Expression 1 or Expression 2 is satisfied until drawing for two lines in the horizontal direction is completed. Only when the expression is satisfied, the current value that is the amplitude of the current signal is Be changed.

As shown in FIG. 17, first, when the deflection angle calculation unit 85 of the optical scanning device 1 finishes drawing for two horizontal lines (step S201), in the current current signal change, the equation 1 or the It is determined whether the current value of the current signal has been changed while satisfying Expression 2 (step S202).
When the current value of the current signal is changed, when the frequency is changed next, the frequency f (θ _{n + 1} ) to be set next to the current signal is stored in the calibration curve storage unit 87, for example, Obtained from the table (step S203). Then, the frequency is changed (set) to the scheduled frequency f (θ _{n + 1} ) (step S204). That is, the frequency f (θ _{n + 1} ) is not corrected.

On the other hand, if the current value of the current signal has not been changed, error processing is executed. That is, in the error process, first, a difference θd between the target value θ _n of the current deflection angle of the movable plate 511a and the estimated value of the current deflection angle is obtained (step S205). Then, a difference frequency fd, which is a frequency (frequency increase) of the current signal corresponding to the difference θd, is obtained (step S206), and the next set frequency f (θ _{n + 1} ) is set using the difference frequency fd. Correct. That is, the difference frequency fd is added to the frequency f (θ _{n + 1} ).

The difference frequency fd is obtained by linear interpolation based on the current frequency f (θ _n ) of the current signal and the previous frequency f (θ _n−1 ) of the current signal. Specifically, the current frequency f (θ _n ) of the current signal, the previous frequency f (θ _n−1 ), the target value θ _n of the current deflection angle, and the previous deflection angle The target value θ _n−1 is substituted into the following equation 4 to obtain the difference frequency fd.
fd = θd · {f (θ _n ) −f (θ _n−1 )} / (θ _n −θ _n−1 ) (Expression 4)

Next, when changing the frequency, the obtained difference frequency fd is added to the frequency f (θ _{n + 1} ) to be set, and the frequency is changed to the added value (corrected value) “f (θ _{n + 1} ) + fd”. (Set) (Step S207). Thereby, the trapezoid distortion of an image can be prevented more reliably.

In addition to the f (θ _{n + 1} ), the θ _n−1 , θ _n , θ _{n + 1} , f (θ _n−1 ), and f (θ _n ) are also stored in the calibration curve storage unit 87. For example, it can be obtained from a table.
Also by such 2nd Embodiment, the effect similar to 1st Embodiment can be exhibited.
Moreover, this 2nd Embodiment is applicable also to the 3rd-5th embodiment mentioned later.
In the present embodiment, when obtaining the difference θd between the target value theta _n of the current deflection angle, although using the estimated value of the current deflection angle, the present invention is not limited thereto, for example, the angle detecting means The detected value (measured value) of the deflection angle detected by 52 may be used.

<Third Embodiment>
Next, a third embodiment of the optical scanning device of the present invention will be described.
FIG. 18 is a block diagram of an optical scanning device according to the third embodiment of the present invention, and FIG. 19 is a schematic perspective view showing an actuator of the optical scanning device according to the third embodiment of the present invention.
Hereinafter, the optical scanning device according to the third embodiment will be described focusing on the differences from the first embodiment described above, and description of similar matters will be omitted.

  As shown in FIGS. 18 and 19, the optical scanning device 1 of the third embodiment has a temperature detection means 61 that detects the temperature of the actuator 51. Since the resonance frequency of the actuator 51 changes according to the temperature, the optical scanning device 1 detects the detection result of the temperature detection means 61 and the vertical position (the drawing line 141) on the projection surface 21 where the laser light LL is scanned. The magnitude and frequency of the drive signal are each changed based on the vertical position). Thereby, the movable plate 511a can be reliably resonated.

  The temperature detection unit 61 includes a temperature sensor 611 and a temperature detection unit 612. The temperature sensor 611 detects, as the temperature of the actuator 51, the temperature of the connecting portion 511d, which is a portion having a large influence on the resonance frequency of the actuator 51, and is provided on the connecting portion 511d. As the temperature sensor 611, for example, a thermistor, a device using a semiconductor resistor, or the like can be used.

The temperature detection unit 612 detects the voltage output from the temperature sensor 611 and obtains (detects) the temperature of the actuator 51 based on the detected value. A signal including the detected temperature information is transmitted from the temperature detection unit 612 to the deflection angle calculation unit 85 of the operation control device 8.
The calibration curve storage unit 87 also scans the projection surface 21 with a laser beam LL having a constant amplitude along the vertical direction in the light emission state and satisfying the condition for the movable plate 511a to resonate. The vertical position of the LL on the projection plane 21 (the vertical position of the drawing line 141), the temperature detected by the temperature detection means 61, the magnitude of the drive signal of the actuator 51, the frequency of the drive signal, and the movable plate A calibration curve such as a table or an arithmetic expression (function) indicating the relationship between the target angle (target target angle) of the swing angle 511a is stored. That is, the calibration curve storage unit 87 stores drive signal data for each temperature. In other words, the table described in the first embodiment is provided for each temperature. When drawing an image, the calibration curve is used, and the magnitude of the drive signal corresponding to the position of the laser beam LL scanned on the projection plane 21 in the vertical direction on the projection plane 21 and the temperature detected by the temperature detection means 61. Then, the frequency of the drive signal and the target value of the deflection angle of the movable plate 511a are respectively acquired, and the magnitude and frequency of the drive signal are changed as described above.
According to the third embodiment, the same effect as that of the first embodiment can be exhibited.
The third embodiment can also be applied to the second embodiment and a fifth embodiment to be described later.

<Fourth embodiment>
Next, a fourth embodiment of the optical scanning device of the present invention will be described.
FIG. 20 is a block diagram of an optical scanning device according to the fourth embodiment of the present invention.
Hereinafter, the optical scanning device according to the fourth embodiment will be described focusing on the differences from the first embodiment described above, and description of similar matters will be omitted.

  As shown in FIG. 20, the optical scanning device 1 according to the fourth embodiment includes a temperature detection unit 61 that detects the temperature of the actuator 51, a temperature control unit 62, a heater control unit 63, and a heater that heats the actuator 51 ( Heating means) 64. Since the resonance frequency of the actuator 51 changes according to the temperature, the temperature control unit 62, the heater control unit 63, and the heater 64 adjust the temperature of the actuator 51 to the target temperature based on the detection result of the temperature detection unit 61. . Therefore, the temperature control unit 62, the heater control unit 63, and the heater 64 constitute a temperature adjusting unit. Note that the temperature detection means 61 is the same as that of the third embodiment described above, and a description thereof will be omitted.

The heater 64 is provided in the vicinity of the connecting portions 511c and 511d of the actuator 51, and mainly heats the connecting portions 511c and 511d. As the heater 64, for example, a heating wire or the like can be used, and heating is performed by applying a voltage from the heater control unit 63 to the heater 64.
A signal including information on the temperature detected by the temperature detector 61 is transmitted to the temperature controller 62. The temperature control unit 62 controls the operation (drive) of the heater 64 via the heater control unit 63 so that the detected temperature becomes the target temperature.

  In other words, the temperature control unit 62 compares the detected temperature with the target temperature, obtains a difference between the detected temperature and the target temperature, and if the detected temperature is lower than the target temperature, the heater 64 corresponds to the difference. And the temperature of the actuator 51 is increased. Further, when the detected temperature is higher than the target temperature, the temperature control unit 62 stops the heater 64 and lowers the temperature of the actuator 51. This control is repeatedly performed, and the temperature of the actuator 51, in particular, the temperatures of the connecting portions 511c and 511d, which are portions having a large influence on the resonance frequency of the actuator 51, are maintained at the target temperature. Thereby, the movable plate 511a can be reliably resonated. Note that the target temperature is set to a temperature sufficiently higher than the room temperature.

  Note that the calibration curve storage unit 87 projects the conditions corresponding to the target temperature, the fluctuation width of the laser beam LL is constant along the vertical direction in the light emission state, and the condition that the movable plate 511a resonates. The vertical position (the vertical position of the drawing line 141) on the projection surface 21 of the laser light LL that scans the surface 21, the magnitude of the drive signal of the actuator 51, the frequency of the drive signal, and the swing of the movable plate 511a A calibration curve such as a table indicating a relationship with a target value (target deflection angle) of a corner and an arithmetic expression (function) is stored.

According to the fourth embodiment, the same effect as that of the first embodiment can be exhibited.
The fourth embodiment can also be applied to the second embodiment and a fifth embodiment to be described later.
In the present invention, as a cooling means for cooling the actuator 51, for example, a Peltier element or the like may be provided. Further, instead of the heater 64, for example, a Peltier element or the like may be provided as a heating / cooling means capable of performing heating and cooling. According to this, the temperature of the actuator 51 can be more reliably held at the target temperature.

<Fifth Embodiment>
Next, a fifth embodiment of the optical scanning device of the present invention will be described.
FIG. 21 is a schematic plan view showing an actuator provided in the optical scanning device according to the fifth embodiment of the present invention. 22 is a cross-sectional view taken along line BB in FIG. FIG. 23 is a block diagram showing voltage applying means of driving means provided in the actuator shown in FIG. FIG. 24 is a diagram illustrating an example of voltages generated in the first voltage generation unit and the second voltage generation unit illustrated in FIG. 23. 25A and 25B are diagrams for explaining the operation in the odd-numbered frame of the optical scanning device according to the fifth embodiment of the present invention. FIG. 25A is a side view and FIG. 25B is a front view. is there. In the following, for convenience of explanation, the front side in FIG. 21 is referred to as “up”, the back side in FIG. 21 is referred to as “down”, the right side is referred to as “right”, and the left side is referred to as “left”. The upper side, the lower side is called “lower”, the right side is called “right”, and the left side is called “left”.

Hereinafter, the optical scanning device according to the fifth embodiment will be described focusing on the differences from the first embodiment described above, and description of similar matters will be omitted.
The optical scanning device of the fifth embodiment is the first embodiment except that the configuration of the actuator provided in the optical scanning unit is different and that the trajectory of scanning (horizontal scanning) in the first direction on the projection surface 21 is not a straight line. It is almost the same as the form.
The optical scanning unit 5 has one actuator 53 of a so-called two-degree-of-freedom vibration system.

  The actuator 53 includes a base 54 having a first vibration system 54 a, a second vibration system 54 b, and a support portion 54 c as shown in FIG. 21, a counter substrate 56 disposed to face the base 54, and a base 54. A spacer member 55 provided between the substrate 56, a permanent magnet 57, and a coil 58 are provided. The second vibration system 54b side constitutes the main part of the horizontal scanning mechanism.

The first vibration system 54a includes a frame-shaped drive unit 541a provided inside the frame-shaped support unit 54c, and a pair of first connection units 542a that support the drive unit 541a on the support unit 54c. 543a.
The second vibration system 54b includes a movable plate 541b provided inside the drive unit 541a, and a pair of second coupling portions 542b and 543b that support the movable plate 541b on both sides of the drive unit 541a. Yes.
The drive unit 541a has an annular shape in a plan view of FIG. The shape of the drive unit 541a is not particularly limited as long as it has a frame shape. For example, the drive unit 541a may have a quadrangular ring shape in a plan view of FIG. A permanent magnet 57 is joined to the lower surface of the driving unit 541a.

  Each of the first connecting portions 542a and 543a has a longitudinal shape and can be elastically deformed. The first connecting portions 542a and 543a connect the driving portion 541a and the supporting portion 54c so that the driving portion 541a can be rotated with respect to the supporting portion 54c, respectively. Such first connecting portions 542a and 543a are provided coaxially with each other, and the drive portion 541a is connected to the support portion 54c around this axis (hereinafter referred to as “rotation center axis J1”). And is configured to rotate.

The first connecting portion 542a is provided with a piezoelectric element 521 for detecting the angle (rotation angle around the rotation center axis J1) (behavior) of the movable plate 541b.
The movable plate 541b has a circular shape in plan view of FIG. However, the shape of the movable plate 541b is not particularly limited as long as the movable plate 541b can be formed inside the drive unit 541a. For example, the movable plate 541b may have an elliptical shape or a rectangular shape in plan view of FIG. It may be done. A light reflecting portion 544b having light reflectivity is formed on the upper surface of the movable plate 541b.

  Each of the second connecting portions 542b and 543b has a longitudinal shape and can be elastically deformed. The second connecting portions 542b and 543b connect the movable plate 541b and the drive portion 541a so that the movable plate 541b can be rotated with respect to the drive portion 541a, respectively. Such second connecting portions 542b and 543b are provided coaxially with each other, and the movable plate 541b is located with respect to the drive portion 541a around this axis (hereinafter referred to as “rotation center axis J2”). It is configured to rotate.

The second connecting portion 542b is provided with a piezoelectric element 521 for detecting the angle (rotation angle around the rotation center axis J2) (behavior) of the movable plate 541b.
As shown in FIG. 21, the rotation center axis J1 and the rotation center axis J2 are orthogonal to each other. Further, the centers of the drive unit 541a and the movable plate 541b are respectively located on the intersections of the rotation center axis J1 and the rotation center axis J2 in the plan view of FIG.

As shown in FIG. 22, the base 54 as described above is bonded to the counter substrate 56 via the spacer member 55. A coil 58 that generates a magnetic field acting on the permanent magnet 57 is provided on the upper surface of the counter substrate 56.
In the plan view of FIG. 21, the permanent magnet 57 passes through the intersection of the rotation center axis J1 and the rotation center axis J2, and is inclined with respect to the rotation center axis J1 and the rotation center axis J2. It is provided along the line segment M.

Such a permanent magnet 57 has an S pole on one side in the longitudinal direction and an N pole on the other side with respect to the intersection of the rotation center axis J1 and the rotation center axis J2. In FIG. 22, the left side in the longitudinal direction of the permanent magnet 57 is the S pole and the right side is the N pole.
Further, as shown in FIG. 22, a concave portion 57 a is formed on the upper surface of the permanent magnet 57. The recess 57a is an escape portion for preventing contact between the permanent magnet 57 and the movable plate 541b. By forming such a recess 57a, it is possible to prevent the movable plate 541b from coming into contact with the permanent magnet 57 when the movable plate 541b rotates around the rotation center axis J2.

  The coil 58 is formed so as to surround the outer periphery of the drive unit 541a in a plan view of FIG. Thereby, when the actuator 53 is driven, the contact between the drive unit 541a and the coil 58 can be reliably prevented. As a result, the distance between the coil 58 and the permanent magnet 57 can be made relatively short, and the magnetic field generated from the coil 58 can be applied to the permanent magnet 57 efficiently.

  The coil 58 is electrically connected to the voltage applying means 59. When a predetermined voltage is applied to the coil 58 by the voltage applying means 59, a predetermined current flows through the coil 58, and the rotation axis of the coil 58 is rotated. Magnetic fields in the axial direction perpendicular to the respective axes of J1 and rotation center axis J2 are generated. In this embodiment as well, as in the first embodiment, the drive signal is a current signal, but here, a description will be given assuming that a predetermined current flows when a predetermined voltage is applied by the voltage applying means 59.

As shown in FIG. 23, the voltage applying means 59 includes a first voltage generator 591 that generates a first voltage V1 for rotating the movable plate 541b about the rotation center axis J1, and a movable plate 541b. A second voltage generator 592 for generating a second voltage V2 for rotating around the rotation center axis J2, and the first voltage V1 and the second voltage V2 are superimposed, and the voltage is applied to the coil 58. And a voltage superimposing portion 593 applied to the.
As in FIG. 9 of the first embodiment, the first voltage generator 591 has a first voltage V1 (vertical scanning) that periodically changes at a period T1 that is twice the frame frequency, as shown in FIG. Voltage).

  The first voltage V1 has a waveform like a triangular wave. Therefore, the actuator 53 can perform vertical reciprocating scanning (sub scanning) of light effectively. Note that the waveform of the first voltage V1 is not limited to this. Here, the frequency (1 / T1) of the first voltage V1 is not particularly limited as long as it is a frequency suitable for vertical scanning, but is preferably 15 Hz or more and 40 Hz or less (about 30 Hz).

In the present embodiment, the frequency of the first voltage V1 is different from the torsional resonance frequency of the first vibration system 54a configured by the drive unit 541a and the pair of first coupling portions 542a and 543a. Has been adjusted.
On the other hand, as shown in FIG. 24B, the second voltage generator 592 generates a second voltage V2 (horizontal scanning voltage) that periodically changes at a period T2 different from the period T1. .
The second voltage V2 has a waveform like a sine wave. Therefore, the actuator 53 can perform main scanning of light effectively. Note that the waveform of the second voltage V2 is not limited to this.

  The frequency of the second voltage V2 is not particularly limited as long as it is higher than the frequency of the first voltage V1 and is suitable for horizontal scanning, but is preferably 10 kHz or more and 40 kHz or less. Thus, by setting the frequency of the second voltage V2 to 10 kHz or more and 40 kHz or less, and setting the frequency of the first voltage V1 to about 30 Hz as described above, the frequency suitable for drawing on the projection surface 21 is obtained. The movable plate 541b can be rotated around the rotation center axis J1 and the rotation center axis J2. However, if the movable plate 541b can be rotated around the rotation center axis J1 and the rotation center axis J2, the combination of the frequency of the first voltage V1 and the frequency of the second voltage V2 can be obtained. There is no particular limitation.

In the present embodiment, the frequency of the second voltage V2 is adjusted to be equal to the torsional resonance frequency of the second vibration system 54b configured by the movable plate 541b and the pair of second coupling portions 542b and 543b. Has been. Thereby, the rotation angle around the rotation center axis J2 of the movable plate 541b can be increased.
When the resonance frequency of the first vibration system 54a is f ₁ [Hz] and the resonance frequency of the second vibration system 54b is f ₂ [Hz], f ₁ and f ₂ are f ₂ > f. ₁ is preferably satisfied, and more preferably f ₂ ≧ 10f ₁ is satisfied. As a result, the movable plate 541b is rotated more smoothly around the rotation center axis J1 at the frequency of the second voltage V2 while being smoothly rotated at the frequency of the first voltage V1. Can do.

The first voltage generator 591 and the second voltage generator 592 are each connected to the operation control device 8 and are driven based on a signal from the operation control device 8. A voltage superimposing unit 593 is connected to the first voltage generating unit 591 and the second voltage generating unit 592.
The voltage superimposing unit 593 includes an adder 593 a for applying a voltage to the coil 58. The adder 593a receives the first voltage V1 from the first voltage generator 591 and receives the second voltage V2 from the second voltage generator 592 so that these voltages are superimposed and applied to the coil 58. It has become.
The actuator 53 configured as described above is driven as follows.

For example, the first voltage V1 as shown in FIG. 24A and the voltage V2 as shown in FIG. 24B are superimposed by the voltage superimposing unit 593, and the superimposed voltage is applied to the coil 58 ( This superimposed voltage is also referred to as “voltage V3”.
Then, by the voltage corresponding to the first voltage V1 in the voltage V3, the magnetic pole which tries to attract the south pole side of the permanent magnet 57 to the coil 58 and separate the north pole side from the coil 58, and permanent The magnetic pole 57 is alternately switched to the magnetic field to be attracted to the coil 58 while the south pole side of the magnet 57 is to be separated from the coil 58. As a result, the drive unit 541a rotates around the rotation center axis J1 at the frequency of the first voltage V1 together with the movable plate 541b while twisting and deforming the first coupling portions 542a and 543a.

  The frequency of the first voltage V1 is set to be extremely lower than the frequency of the second voltage V2, and the resonance frequency of the first vibration system 54a is the resonance frequency of the second vibration system 54b. Designed lower than. Therefore, the first vibration system 54a is easier to vibrate than the second vibration system 54b, and the movable plate 541b is rotated around the rotation center axis J2 by the first voltage V1. Can be prevented.

On the other hand, a magnetic field that attempts to attract the south pole side of the permanent magnet 57 to the coil 58 and separates the north pole side from the coil 58 by a voltage corresponding to the second voltage V2 in the voltage V3, The magnetic pole 57 is alternately switched to the magnetic field to be attracted to the coil 58 while the south pole side of the magnet 57 is to be separated from the coil 58. As a result, the movable plate 541b rotates around the rotation center axis J2 at the frequency of the second voltage V2 while twisting and deforming the second connecting portions 542b and 543b.
Since the frequency of the second voltage V2 is equal to the torsional resonance frequency of the second vibration system 54b, the movable plate 541b is predominantly rotated around the rotation center axis J2 by the second voltage V2. Can do. Therefore, it is possible to prevent the movable plate 541b from rotating around the rotation center axis J1 by the second voltage V2.

  According to the actuator 53 as described above, laser light (light) can be scanned two-dimensionally with one actuator, and space saving of the optical scanning unit 5 can be achieved. Further, for example, when an actuator and a galvanometer mirror are used as in the first embodiment, the relative positional relationship between the actuator and the galvanometer mirror must be set with high accuracy. Therefore, manufacturing can be facilitated.

In this embodiment, unlike FIG. 7 of the first embodiment, as shown in FIG. 25, the laser beam LL is projected on the projection surface 21 in the light emission state in which the laser beam (light) LL is emitted from the light source unit 4. A plurality of drawing lines (scanning lines) 141 that are trajectories of the laser beam LL on the projection surface 21 when two-dimensionally scanning are arranged in a zigzag manner and distorted.
In addition, since the scanning line is distorted, the video data calculation unit 82 reads out data from the video data storage unit 81 while calculating data corresponding to pixel data to be drawn on the line to be scanned, and draws the drawing timing. Based on the drawing timing information input from the generation unit 83, after performing various correction calculations, the luminance data of each color is sent to the light source modulation unit 84.

Regarding the processing other than the above, the same processing as in the first embodiment is performed so that the fluctuation width of the laser light LL is constant along the vertical direction in the light emission state, and the movable plate 541b resonates in horizontal scanning. It has become.
According to the fifth embodiment, the same effect as that of the first embodiment can be exhibited.
The fifth embodiment can also be applied to the second to fourth embodiments.

The optical scanning device of the present invention has been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each part is replaced with an arbitrary configuration having the same function. can do. In addition, any other component may be added to the present invention.
Further, the present invention may be a combination of any two or more configurations (features) of the above embodiments.

  Further, in the above-described embodiment, the optical scanning device is described which is placed on a support base and draws an image using the surface of the support base as a projection surface. However, the present invention is not limited to this, for example, Alternatively, an image may be drawn on a screen or a wall. When an image is drawn on a screen, the screen may or may not be included as a constituent element of the present invention.

  In the first to third embodiments, the optical scanning unit is configured to be resonantly driven (operated using resonance) as the first direction scanning unit (scanning mechanism) that scans in the first direction. Although the galvanometer mirror is used as the second direction scanning unit that scans in the second direction using the actuator of the present invention, the present invention is not limited to this, and the second direction scanning unit is replaced with a galvano mirror. For example, a polygon mirror, an actuator driven in resonance, or the like may be used.

Further, in the present invention, the vertical scanning may be performed only in the forward path, and the image may be drawn by performing the horizontal scanning in each of the forward path and the backward path in the vertical scanning path.
In the embodiment, the first direction is the “horizontal direction” and the second direction is the “vertical direction”. However, the present invention is not limited to this. For example, the first direction is the “vertical direction”. The second direction may be the “horizontal direction”.
In the embodiment, the dichroic mirrors 43r, 43g, and 43b are used to combine the red laser light RR, the green laser light GG, and the blue laser light BB to emit one laser light (light) LL. For example, a dichroic prism may be used for coupling.

  DESCRIPTION OF SYMBOLS 1 ... Optical scanning device 2 ... Support stand 21 ... Projection surface 4 ... Light source unit (light emission part) 41r, 41g, 41b ... Laser light source 410r, 410g, 410b ... Drive circuit 42r, 42g, 42b ... ... collimator lens 420r, 420g, 420b ... light source 43r, 43g, 43b ... dichroic mirror 5 ... optical scanning part 51 ... actuator 511 ... base 511a ... movable plate 511b ... support part 511c, 511d ... Connecting portion 511e …… Light reflecting portion 512 …… Spacer member 513 …… Counter substrate 514 …… Permanent magnet 515 …… Coil 516 …… Energizing means 517 …… Drive means 52 …… Angle detecting means 521 …… Piezoelectric element 522… ... electromotive force detector 523 ... angle detector 53 ... actuator 5 …… Substrate 54a …… First vibration system 541a …… Drive parts 542a, 543a …… First connection part 54b …… Second vibration system 541b …… Movable plates 542b, 543b …… Second connection part 544b …… Light reflecting portion 54c …… Supporting portion 55 …… Spacer member 56 …… Counter substrate 57 …… Permanent magnet 57a …… Recessed portion 58 …… Coil 59 …… Voltage applying means 591 …… First voltage generating portion 592… ... second voltage generator 593 ... voltage superimposing unit 593a ... adder 61 ... temperature detection means 611 ... temperature sensor 612 ... temperature detection unit 62 ... temperature control unit 63 ... heater control unit 64 ... Heater 300 …… Scan projector 8 …… Operation control device 81 …… Video data storage unit 82 …… Video data calculation unit 83 …… Drawing timing Generation unit 84 …… light source modulation unit 85 …… deflection angle calculation unit 851 …… comparison calculation unit 852 …… drive signal instruction unit 86 …… angle instruction unit 87 …… calibration curve storage unit 12 …… galvano mirror 121 …… Mirror 122 ... Motor 123 ... Drive circuit 124 ... Drive means 13 ... Angle detection means 131 ... Encoder 132 ... Angle detector 141 ... Drawing line 142 ... Drawing area 143 ... Drawable area S101 to S107 …… Steps S201 to S207 …… Steps LL, RR, GG, BB …… Laser beam J, Ja, J1, J2 …… Rotation center axis

Claims (12)

A light emitting portion for emitting light;
The light emitted from the light emitting section is scanned in a first direction and in a second direction orthogonal to the first direction at a scanning speed slower than the scanning speed in the first direction. An optical scanning unit;
Control means for controlling the optical scanning unit,
The optical scanning unit includes: a reflective surface that scans the light emitted from the light emitting unit in the first direction; and a scanning mechanism that resonantly drives the reflective surface when a predetermined drive signal is supplied. Have
The frequency characteristic of the scanning mechanism is that when the driving frequency exceeds the resonance frequency, the deflection angle that is the angle at which the reflecting surface is rotated to the maximum decreases rapidly, and the driving frequency becomes larger than the resonance frequency. The reflective surface does not resonate or stops, and when the magnitude of the drive signal is reduced, the resonance frequency is reduced,
When increasing the deflection angle , the control means increases the magnitude of the drive signal first, then increases the frequency of the drive signal, and when decreasing the deflection angle, An optical scanning device comprising a changing means for reducing the frequency first and then reducing the magnitude of the drive signal . The scanning mechanism so that the fluctuation width in the first direction of the light emitted from the light emitting unit is aligned along the second direction on the projection surface on which light is projected by the light scanning unit. Storage means for storing drive signal data including the drive signal data supplied to
The optical scanning device according to claim 1, wherein the changing unit includes a determining unit that determines a magnitude of the driving signal and a frequency of the driving signal based on the driving signal data. Angle detecting means for detecting the angle of the reflecting surface;
The change means detects the timing of changing the other of the magnitude of the drive signal and the frequency of the drive signal after changing one of the magnitude of the drive signal and the frequency of the drive signal. The optical scanning device according to claim 1, wherein the optical scanning device is determined based on a result and a frequency of the drive signal. The change means includes a deflection angle estimation unit that estimates the deflection angle based on the detection result of the angle detection means and the frequency of the drive signal,
A determination unit that determines whether or not the estimated value of the deflection angle and the target value of the deflection angle match;
The optical scanning device according to claim 3, wherein when the estimated value of the deflection angle and the target value of the deflection angle coincide with each other, the other of the magnitude of the drive signal and the frequency of the drive signal is changed.   The light according to claim 4, wherein the changing unit does not change the other of the magnitude of the drive signal and the frequency of the drive signal when the estimated value of the shake angle and the target value of the shake angle do not match. Scanning device.   The changing means, when the estimated value of the deflection angle and the target value of the deflection angle do not match, when changing one of the magnitude of the drive signal and the frequency of the drive signal next The optical scanning device according to claim 5, further comprising: a correction unit that corrects the value of.   The changing means changes the magnitude of the drive signal first, changes the frequency of the drive signal later, changes the frequency of the drive signal first, and sets the magnitude of the drive signal. 2. A second mode to be changed later, wherein when the deflection angle is increased, the operation is performed in the first mode, and when the deflection angle is decreased, the operation is performed in the second mode. 7. The optical scanning device according to any one of items 6 to 6. Performs scanning of the second direction outward and the return path of each in each of the forward and backward of the second direction of scanning, claims 1 to draw the image by performing scanning of said first direction 7 The optical scanning device according to any one of the above. Temperature detecting means for detecting the temperature of the scanning mechanism;
It said changing means, based on a detection result of said temperature detecting means, the optical scanning apparatus according to any one of claims 1 to 8 to change the frequency of the magnitude and the driving signal of the driving signal. Temperature detecting means for detecting the temperature of the scanning mechanism;
The storage means stores the drive signal data for each temperature,
The optical scanning device according to claim 2, wherein the determination unit determines the magnitude of the drive signal to be changed and the frequency of the drive signal based on a detection result of the temperature detection unit and the data for the drive signal. . Temperature detecting means for detecting the temperature of the scanning mechanism;
On the basis of the detection result of the temperature detecting means, the optical scanning apparatus according to any one of claims 1 to 8 having a temperature adjusting means for adjusting the target temperature the temperature of the scanning mechanism. The scanning mechanism is rotatably provided, the movable plate having the reflection surface, a support portion that rotatably supports the movable plate, a connecting portion that connects the movable plate and the support portion, An actuator comprising a driving means for rotating the movable plate;
The optical scanning unit includes an optical scanning device according to any one of claims 1 to 11 comprising a galvano mirror having a reflecting surface for scanning the light emitted from the light emitting portion in the second direction.

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