JP2010204218A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which time aperture rate is enhanced and the trapezoidal distortion and a distortion in a second direction of an image are easily and certainly prevented with a simple configuration. <P>SOLUTION: The image forming apparatus 1 includes: a light emission part; a first reflection face and a second reflection face which are turnably furnished; and an optical scanning part 5 which two-dimensionally scans the light emitted from the light emission part in the first direction and the second direction on the projection face 21. When viewed from the turning center axis of the second reflection face, the irradiation position on the second refection face of the light reflected on the first reflection face is varied by the turning of the second reflection face, the second reflection face has a curved shape such that the swing width of light in the first direction on the projection face 21 is kept constant along the second direction and pitch of the plot lines running along the second direction on the projection face 21 is kept constant when the light is emitted from the light emission part and the light emitted from the light emission part is scanned two-dimensionally on the projection face 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus.

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. 19, the light locus 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 area 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 mirror angle 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. . In particular, as shown in FIG. 20, 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). There is a problem that the ratio of the period during which the image processing is performed decreases, and the luminance per pixel decreases. Further, since the time aperture ratio is reduced, the drawing time per pixel is shortened, and it is necessary to increase the modulation speed of the light source, and the modulation speed of the light source may be insufficient.

Further, in the scan projector 300, as the distortion caused by the optical path difference to the projection surface 21, the interval between the drawing lines 141 arranged along the vertical direction on the projection surface 21 is not constant, and the distortion in the vertical direction is also generated. Is required.
Normally, the drive of the vertical scanning mirror is controlled so that the interval between the drawing lines 141 arranged along the vertical direction on the projection surface 21 is constant within the drawing region 142. That is, the angular speed control (speed control) is performed to decrease the angular speed (speed) of the vertical scanning mirror as the position of the portion of the drawing area 142 that scans the light is farther from the scan projector 300 in the vertical direction.

However, a greater distortion correction is required at a position farther from the scan projector 300 in the vertical direction. That is, as the position is farther from the scan projector 300 in the vertical direction, the variation in the interval of the drawing line 141 with respect to the displacement of the angle of the vertical scanning mirror becomes larger. In particular, as shown in FIG. When projecting an image from an oblique direction, it is very difficult to control the angle of the vertical scanning mirror. For example, when the light is scanned on one drawing line 141, the rotation angle of the vertical scanning mirror may be less than the resolution of the angle detection means for detecting the angle of the vertical scanning mirror. .
As means for solving the above-described problem, a technique for preventing trapezoidal distortion and vertical distortion of an image by providing a plurality of mirrors has been proposed (for example, see Patent Documents 1 and 2).
However, the scan projectors of Patent Documents 1 and 2 require a plurality of mirrors, and it is necessary to arrange each mirror with high accuracy, resulting in a complicated configuration.

JP 2003-75767 A JP 2004-252012 A

  An object of the present invention is to provide an image forming apparatus that can easily and reliably prevent trapezoidal distortion and distortion in the second direction with a simple configuration and a high time aperture ratio. .

Such an object is achieved by the present invention described below.
The image forming apparatus of the present invention is configured to draw an image by scanning light on a projection surface,
A light emitting portion for emitting light;
A first reflection surface that is rotatably provided to reflect light emitted from the light emitting portion, and a rotation member that is capable of reflecting light reflected by the first reflection surface toward the projection surface. The second reflecting surface, and by rotating each of the first reflecting surface and the second reflecting surface, the light emitted from the light emitting unit is directed to the projection surface. An optical scanning unit that scans two-dimensionally by scanning in a first direction and scanning in a second direction orthogonal to the first direction at a scanning speed slower than the scanning speed in the first direction; With
When viewed from the direction of the rotation center axis of the second reflecting surface, the second reflecting surface rotates, so that the light reflected by the first reflecting surface is directed to the second reflecting surface. The irradiation position is configured to change,
The second reflection surface is in a light emitting state in which light is emitted from the light emitting unit, and when the light emitted from the light emitting unit is scanned two-dimensionally with respect to the projection surface, The fluctuation width of the light in the first direction is constant along the second direction, and the interval between the drawing lines arranged along the second direction on the projection plane is constant. It has a curved surface shape.

As a result, the fluctuation width in the first direction of the light on the projection surface in the light emitting state in which light is emitted from the light emitting portion is constant along the second direction, so that the non-drawing region is greatly reduced. Thus, the trapezoidal distortion (distortion in the first direction) of the image can be prevented while increasing the time aperture ratio.
Further, complicated control for the second reflecting surface is not required, and distortion of the image in the second direction can be prevented easily and reliably.

Since the time aperture ratio can be increased, the drawing time per pixel can be lengthened, and thereby the luminance per pixel can be increased. In addition, the modulation speed of the light source can be lowered, and the modulation speed of the light source can be prevented from being insufficient, and an image can be reliably drawn.
Further, by specifying the shape of the second reflecting surface, the trapezoidal distortion of the image and the distortion in the second direction are prevented, so that the configuration is simple and the number of parts can be reduced.

In the image forming apparatus of the present invention, the shape of the first reflecting surface is a plane,
It is preferable that a deflection angle around the rotation center axis of the first reflecting surface is constant.
Thereby, the trapezoidal distortion of the image and the distortion in the second direction can be prevented with a simpler configuration.
In the image forming apparatus according to the aspect of the invention, it is preferable that the angular velocity of the second reflecting surface is constant.
Thereby, the trapezoidal distortion of the image and the distortion in the second direction can be prevented with a simpler configuration.

In the image forming apparatus according to the aspect of the invention, it is preferable that the second reflecting surface is provided at a position separated from a rotation center axis of the second reflecting surface.
Thereby, the trapezoidal distortion of the image and the distortion in the second direction can be prevented with a simpler configuration.
In the image forming apparatus of the present invention, the curvature of the second reflecting surface in a cross section perpendicular to the rotation center axis of the second reflecting surface changes along the second reflecting surface. It is preferable.
Thereby, the distortion of the image in the second direction can be prevented more easily and reliably.

In the image forming apparatus of the present invention, the second reflecting surface has a curved concave surface portion curved in a concave shape,
It is preferable that the curvature of the curved concave surface in a cross section perpendicular to the rotation center axis of the second reflecting surface changes along the curved concave surface.
Thereby, the distortion of the image in the second direction can be prevented more easily and reliably.

In the image forming apparatus according to the aspect of the invention, when light emitted from the light emitting unit is scanned two-dimensionally with respect to the projection surface in a light emitting state in which light is emitted from the light emitting unit, correspondingly, The light reflected by the first reflecting surface is two-dimensionally scanned on the second reflecting surface,
The curve corresponding to the position in the second direction having the longest distance in the second direction from the image forming apparatus among the areas corresponding to the curved concave surface in the drawing area for drawing the image on the projection surface. The curvature gradually increases from the position on the concave surface toward the position on the curved concave surface corresponding to the position in the second direction with the shortest distance in the second direction from the image forming apparatus. Preferably it is.
Thereby, the distortion of the image in the second direction can be more reliably prevented.

In the image forming apparatus of the present invention, the second reflecting surface has a curved convex surface portion curved in a convex shape.
It is preferable that a curvature of a portion of the curved convex surface in a cross section perpendicular to the rotation central axis of the second reflecting surface changes along the curved convex surface.
Thereby, the distortion of the image in the second direction can be prevented more easily and reliably.
In the image forming apparatus according to the aspect of the invention, when light emitted from the light emitting unit is scanned two-dimensionally with respect to the projection surface in a light emitting state in which light is emitted from the light emitting unit, correspondingly, The light reflected by the first reflecting surface is two-dimensionally scanned on the second reflecting surface,
Of the region corresponding to the curved convex surface in the drawing region for drawing the image on the projection surface, the curve corresponding to the position in the second direction with the shortest distance in the second direction from the image forming apparatus. The curvature gradually increases from the position on the convex surface toward the position on the curved convex surface corresponding to the position in the second direction with the longest distance in the second direction from the image forming apparatus. Preferably it is.
Thereby, the distortion of the image in the second direction can be more reliably prevented.

In the image forming apparatus according to the aspect of the invention, the curvature of the second reflecting surface in a cross section perpendicular to the direction on the second reflecting surface corresponding to the second direction is the second direction. It is preferable to change along the direction on the corresponding second reflecting surface.
Thereby, the trapezoid distortion of an image can be prevented more easily and reliably.
In the image forming apparatus of the present invention, the second reflecting surface has a curved concave surface portion curved in a concave shape,
The curvature of the curved concave surface in a cross section perpendicular to the direction on the second reflecting surface corresponding to the second direction is on the second reflecting surface corresponding to the second direction. It is preferable that it is changing along the direction.
Thereby, the trapezoid distortion of an image can be prevented more easily and reliably.

In the image forming apparatus according to the aspect of the invention, when light emitted from the light emitting unit is scanned two-dimensionally with respect to the projection surface in a light emitting state in which light is emitted from the light emitting unit, correspondingly, The light reflected by the first reflecting surface is two-dimensionally scanned on the second reflecting surface,
The curve corresponding to the position in the second direction with the shortest distance in the second direction from the image forming apparatus among the areas corresponding to the curved concave surface in the drawing area for drawing the image on the projection surface. The curvature gradually increases from the position on the concave surface toward the position on the curved concave surface corresponding to the position in the second direction with the longest distance in the second direction from the image forming apparatus. Preferably it is.
Thereby, the trapezoidal distortion of the image can be prevented more reliably.

In the image forming apparatus of the present invention, the second reflecting surface has a curved convex surface portion curved in a convex shape.
The curvature of the curved convex surface in a cross section perpendicular to the direction on the second reflecting surface corresponding to the second direction is on the second reflecting surface corresponding to the second direction. It is preferable that it is changing along the direction.
Thereby, the trapezoid distortion of an image can be prevented more easily and reliably.

In the image forming apparatus according to the aspect of the invention, when light emitted from the light emitting unit is scanned two-dimensionally with respect to the projection surface in a light emitting state in which light is emitted from the light emitting unit, correspondingly, The light reflected by the first reflecting surface is two-dimensionally scanned on the second reflecting surface,
The curve corresponding to the position in the second direction with the longest distance in the second direction from the image forming apparatus among the areas corresponding to the curved convex surface in the drawing area for drawing the image on the projection surface. The curvature gradually increases from the position on the convex surface toward the position on the curved convex surface corresponding to the position in the second direction with the shortest distance in the second direction from the image forming apparatus. Preferably it is.
Thereby, the trapezoidal distortion of the image can be prevented more reliably.

In the image forming apparatus according to the aspect of the invention, the optical scanning unit is rotatably provided, has a movable plate having the first reflecting surface, a support unit that rotatably supports the movable plate, and the movable plate. And an actuator comprising: a connecting portion that connects the support portion; and a driving means that rotates the movable plate;
It is preferable to include a galvanometer mirror having the second reflecting surface.
Thereby, it is possible to prevent trapezoidal distortion and distortion in the second direction of the image with high energy efficiency and more reliably increasing the time aperture ratio.
The image forming apparatus of the present invention preferably includes a screen having the projection surface.
Thereby, the visibility of an image improves.

1 is a diagram illustrating a first embodiment of an image forming apparatus of the present invention. FIG. 2 is a schematic perspective view showing an actuator of the image forming apparatus shown in FIG. 1. FIG. 2 is a schematic cross-sectional view showing driving of an actuator of the image forming apparatus shown in FIG. 1. It is a figure which shows the galvanometer mirror of the image forming apparatus 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 image forming apparatus illustrated in FIG. 1. FIG. 2 is a diagram for explaining an operation and the like of the image forming apparatus illustrated in FIG. 1 (a is a side view, b is a front view, and c is a bottom view). FIG. 2 is a diagram illustrating an example of a galvanometer mirror of the image forming apparatus illustrated in FIG. 1 (a is a plan view, and b and c are cross-sectional views). It is a figure which shows the other example of the mirror of the galvanometer mirror of the image forming apparatus shown in FIG. 1 (a is a top view, b and c are sectional drawings). 2A and 2B are diagrams for explaining a shape of a mirror of a galvanometer mirror of the image forming apparatus shown in FIG. 1 (a is a side view, and b is a front view). 2A and 2B are diagrams for explaining a shape of a mirror of a galvanometer mirror of the image forming apparatus shown in FIG. 1 (a is a side view, and b is a front view). 2A and 2B are diagrams for explaining a shape of a mirror of a galvanometer mirror of the image forming apparatus shown in FIG. 1 (a is a side view, and b is a front view). 2A and 2B are diagrams for explaining a shape of a mirror of a galvanometer mirror of the image forming apparatus shown in FIG. 1 (a is a side view, and b is a front view). 2A and 2B are diagrams for explaining a shape of a mirror of a galvanometer mirror of the image forming apparatus shown in FIG. 1 (a is a side view, and b is a front view). It is a figure which shows the mirror of the galvanometer mirror of the image forming apparatus shown in FIG. FIG. 2 is a diagram showing a mirror of a galvano mirror and a movable plate of an actuator of the image forming apparatus shown in FIG. 1 (a is the closest distance scan, and b is the farthest distance scan). It is a figure which shows 2nd Embodiment of the image forming apparatus of this invention (a is a side view, b is a front view). It is a figure which shows an example of the mirror of the galvanometer mirror of the image forming apparatus shown in FIG. 16 (a is a top view, b and c are sectional drawings). It is a figure which shows the other example of the mirror of the galvanometer mirror of the image forming apparatus shown in FIG. 16 (a is a top view, b and c are sectional drawings). 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, preferred embodiments of an image forming apparatus of 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 image forming apparatus of the present invention will be described.

1 is a diagram illustrating a first embodiment of an image forming apparatus according to the present invention, FIG. 2 is a schematic perspective view illustrating an actuator of the image forming apparatus illustrated in FIG. 1, and FIG. 3 is an image forming apparatus illustrated in FIG. FIG. 4 is a diagram showing a galvano mirror of the image forming apparatus shown in FIG. 1, and FIG. 5 is an operation control unit, an optical scanning unit, and a light source of the image forming apparatus shown in FIG. It is a block diagram which shows a unit. 6 is a diagram for explaining the operation and the like of the image forming apparatus shown in FIG. 1. FIG. 6 (a) is a side view, and FIG. 6 (b) is for a projection plane. FIG. 6C is a bottom view of the front view. 7 is a diagram illustrating an example of a mirror of the galvanometer mirror of the image forming apparatus illustrated in FIG. 1. FIG. 7A is a plan view, and FIG. 7B is a diagram in FIG. FIG. 7C is a sectional view taken along line AA, and FIG. 7C is a sectional view taken along line BB in FIG. 8 is a diagram showing another example of the galvanometer mirror of the image forming apparatus shown in FIG. 1, in which FIG. 8 (a) is a plan view, and FIG. 8 (b) is FIG. 8 (a). FIG. 8C is a cross-sectional view taken along the line D-D in FIG. 8A. FIG. 9 is a diagram for explaining the shape of the mirror of the galvanometer mirror of the image forming apparatus shown in FIG. 1. FIG. 9 (a) is a side view, and FIG. 9 (b) is a projection plane. FIG. 10 is a diagram for explaining the shape of the galvanometer mirror of the image forming apparatus shown in FIG. 1, FIG. 10 (a) is a side view, and FIG. 10 (b) is a projection plane. FIG. 11 is a diagram for explaining the shape of the galvanometer mirror of the image forming apparatus shown in FIG. 1, in which FIG. 11 (a) is a side view and FIG. 11 (b) is a projection surface. FIG. 12 is a diagram for explaining the shape of the galvanometer mirror of the image forming apparatus shown in FIG. 1, FIG. 12 (a) is a side view, and FIG. 12 (b) is a projection plane. FIG. 13 is a diagram for explaining the shape of the galvanometer mirror of the image forming apparatus shown in FIG. 1. FIG. 13 (a) is a side view, and FIG. 13 (b) is a projection surface. FIG. FIG. 14 is a view showing a mirror of the galvanometer mirror of the image forming apparatus shown in FIG. 15 is a diagram showing the mirror of the galvano mirror and the movable plate of the actuator of the image forming apparatus shown in FIG. 1. FIG. 15 (a) is a diagram showing the closest distance scanning, and FIG. It is a figure which shows the time of farthest distance scanning.
In the following, for convenience of explanation, the upper side in FIGS. 2, 3, and 6 to 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, an image forming apparatus 1 includes a screen (object) 2 and an image forming apparatus main body 3 that scans light on the screen 2 to form (draw) (project) an image (video). Have. Hereinafter, these will be sequentially described.
The surface of the screen 2 on the image forming apparatus main body 3 side constitutes an optical scanning surface on which light is scanned by the image forming apparatus main body 3, that is, a projection surface 21. A predetermined image such as a still image or a moving image is drawn on the projection surface 21 by scanning light with the image forming apparatus main body 3. By using such a screen 2, the visibility of the image is improved.

  The constituent material of the screen 2 is not particularly limited, and for example, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamide, acrylic resin, ABS resin, fluorine resin, epoxy resin, silicone resin, or these are mainly used. Copolymers, blends, polymer alloys and the like can be mentioned, and one or more of these can be used in combination.

Next, the image forming apparatus main body 3 will be described.
As shown in FIG. 1, the image forming apparatus main body 3 includes a light source unit (light emitting unit) 4 that emits light, a light scanning unit 5 that scans light emitted from the light source unit 4 with respect to the projection surface 21, and It has an operation control device (control means) 8 for controlling the operation (drive) of the light source unit 4 and the optical scanning unit 5.

As shown in FIG. 1, the light source unit 4 includes laser light sources 41r, 41g, 41b for each color, collimator lenses 42r, 42g, 42b and dichroic mirrors provided corresponding to the laser light sources 41r, 41g, 41b for each color. 43r, 43g, 43b.
As shown in FIG. 5, each color laser light source 41r, 41g, 41b has drive circuits 410r, 410g, 410b, a red light source 420r, a green light source 420g, and a blue light source 420b, respectively. As shown in FIG. 1, 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. In addition, 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. , 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) 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, and an actuator 51 described later. The angle detection means (behavior detection means) 52 for detecting the angle (behavior) of the movable plate 511a (reflection surface of the light reflecting portion 511e), and the laser light LL emitted from the light source unit 4 in the direction perpendicular to the projection plane 21 Angle detecting means for detecting the angle (behavior) of a galvano mirror (second direction scanning unit) 12 that is a vertical scanning mirror that scans the mirror and a mirror 121 (reflecting surface 125 of the mirror 121) described later of the galvano mirror 12 ( Behavior detecting means) 13.

As shown in FIG. 2, the actuator 51 is a so-called resonance driven type (using resonance), and is 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, and the shape thereof is a plane (planar shape). 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. 3, 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.
In addition, the actuator 51 includes voltage application means (drive circuit) 516 that applies a voltage to the coil 515. The voltage application unit 516 is configured to be able to adjust (change) each condition such as the voltage value and frequency of the voltage to be applied. The voltage applying unit 516, the coil 515, the permanent magnet 514, and the like constitute a driving unit 517 that rotates the movable plate 511a.

A predetermined voltage is applied to the coil 515 from the voltage applying unit 516 under the control of the operation control device 8, and a predetermined current flows.
For example, when an alternating voltage is applied from the voltage application unit 516 to the coil 515 under the control of the operation control device 8, a current flows accordingly, and a magnetic field in the thickness direction of the movable plate 511a (up and down direction in FIG. 3) is generated. And 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. 3A, the right side of the permanent magnet 514 is displaced upward by a 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. 3B, 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.

Also, the current applied can be adjusted by adjusting the voltage applied from the voltage application means 516 to the coil 515 under the control of the operation control device 8, whereby the movable plate 511 a (the reflecting surface of the light reflecting portion 511 e). The swing angle (amplitude) about the rotation center axis J) can be adjusted. In the present embodiment, the deflection angle of the movable plate 511a is made constant. The deflection angle is a maximum angle when the movable plate 511a rotates clockwise (predetermined direction) and a maximum angle when the movable plate 511a subsequently rotates counterclockwise (opposite direction). It is a difference.
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.

  As shown in FIG. 4, the galvanometer mirror 12 has a reflection surface (second reflection surface) 125 that reflects light on the surface, and rotates around a rotation center axis (second rotation center axis) Ja. A mirror 121 provided so as to be movable, and a driving means 124 having a motor (driving source) 122 for rotating the mirror 121 and a driving 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. The shape of the reflection surface 125 of the mirror 121 will be described in detail later.

  As shown in FIG. 1, 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 125 of the mirror 121 of the galvanometer mirror 12, and projected (irradiated) on the projection surface 21 of the screen 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.

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. 2, the angle detection means 52 includes a piezoelectric element 521 provided on the connecting portion 321 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.

Note that the angle of the movable plate 511a to be detected may be set to an angle based on any state of the actuator 51 (the angle is 0 °). For example, the initial state of the actuator 51 (coil 515). The angle when the voltage is not applied to the reference (angle 0 °) can be set.
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 of the galvanometer mirror 12 (the reflection surface 125 of the mirror 121) will be described.
As shown in FIG. 4, 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 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. 5, 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 instruction unit (amplitude instruction unit) 85, and an angle instruction unit 86 are provided. The detailed description of the operation control device 8 will be made together with the description of the operation of the image forming apparatus 1 described later.
In this image forming apparatus 1, the galvanometer mirror 12 of the optical scanning unit 5 is rotated by the mirror 121 (reflection surface 125) when viewed from the direction of the rotation center axis Ja, so that the light reflection unit of the movable plate 511 a is rotated. The irradiation position of the laser beam (light) LL reflected by the reflecting surface 511e to the reflecting surface 125 is changed.

In the present embodiment, as shown in FIG. 15, the reflection surface 125 is provided at a position separated from the rotation center axis Ja, whereby the mirror 121 rotates to reflect the light reflection portion 511 e. The irradiation position of the laser beam LL reflected by the surface to the reflection surface 125 changes. For example, when the laser beam LL is scanned in the horizontal direction so that the vertical distance from the reflecting surface 125 of the mirror 121 in the drawing area 142 passes through the shortest (near) part, the scanning direction shown in FIG. As shown, the laser beam LL is irradiated and reflected on one end (upper right in FIG. 15) of the reflection surface 125. On the other hand, when the laser beam LL is scanned in the horizontal direction so that the vertical distance from the reflecting surface 125 of the mirror 121 in the drawing area 142 passes through the longest (far) part, the laser beam LL is scanned as shown in FIG. As shown, the laser beam LL is irradiated to the other end (lower left in FIG. 15) of the reflection surface 125 and reflected. That is, in the present embodiment, when the laser light LL emitted from the light source unit 4 is scanned two-dimensionally with respect to the projection surface 21 in the light emission state in which the laser light LL is emitted from the light source unit 4, it corresponds to that. Thus, the laser beam LL reflected by the reflecting surface of the light reflecting portion 511e is scanned two-dimensionally on the reflecting surface 125. Further, the angular velocity of the mirror 121 (reflection surface 125) is made constant.
The separation distance of the rotation center axis Ja from the reflecting surface 125 is not particularly limited, and is appropriately determined according to various conditions such as the spot size of the laser beam LL on the reflecting surface 125 and the vertical resolution. Can be set.

  As shown in FIG. 6, the reflecting surface 125 of the mirror 121 is emitted from the light source unit 4 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 the projected laser beam LL is scanned two-dimensionally with respect to the projection plane 21, the horizontal deflection width of the laser beam LL on the projection plane 21 (hereinafter simply referred to as "the deflection width of the laser beam (light) LL"). Also has a curved surface shape that is constant along the vertical direction. In particular, in this embodiment, since the deflection angle around the rotation center axis J of the movable plate 511a (hereinafter, also simply referred to as “the deflection angle of the movable plate 511a”) is constant, the reflecting surface 125 is configured to emit light. When the laser beam LL emitted from the light source unit 4 is two-dimensionally scanned with respect to the projection surface 21 in a state where the deflection angle of the movable plate 511a is constant, the deflection width of the laser beam LL is: It has a curved surface shape that is constant along the vertical direction. Accordingly, the configuration is simple, and the trapezoidal distortion (distortion in the horizontal direction) (distortion in the first direction) of the image can be prevented while increasing the time aperture ratio (ratio of the period during which the image is drawn). .

  The deflection width is the position of the laser beam LL on the projection surface 21 when the movable plate 511a is rotated clockwise (predetermined direction) to the maximum angle in the light emitting state, and subsequently the movable plate. The horizontal distance (interval) from the position of the laser beam LL on the projection plane 21 when 511a is rotated counterclockwise (in the opposite direction) to the maximum angle, that is, as shown in FIG. When the laser beam LL is two-dimensionally scanned on the projection surface 21 in the light emitting state, the horizontal direction of each of a plurality of drawing lines (scanning lines) 141 that are the locus of the laser beam LL on the projection surface 21 Is the length of

Further, as shown in FIG. 6, the reflection surface 125 of the mirror 121 is in the light emission state, and when the laser light LL emitted from the light source unit 4 is scanned two-dimensionally with respect to the projection surface 21, the projection surface 21. It has a curved surface shape such that the interval between drawing lines (scanning lines) 141 arranged along the upper vertical direction is constant. In particular, in this embodiment, since the angular velocity of the mirror 121 is constant, the reflecting surface 125 emits the laser light LL emitted from the light source unit 4 in a light emitting state and in a state where the angular velocity of the mirror 121 is constant. When the projection surface 21 is scanned two-dimensionally, it has a curved surface shape such that the interval between the drawing lines 141 is constant. Accordingly, it is possible to easily and surely prevent distortion in the vertical direction of the image (distortion in the second direction) with a simple configuration.
Further, the image forming apparatus 1 performs scanning in the vertical direction (second direction) (hereinafter also simply referred to as “vertical scanning”) only in the forward path, and in the horizontal path (first direction) in the forward path of the vertical scanning. This scanning (hereinafter also simply referred to as “horizontal scanning”) is performed in each of the forward path and the backward path to draw an image.

  When the laser light LL emitted from the light source unit 4 in the light emission state is scanned two-dimensionally on the projection surface 21, the locus of the laser light LL on the projection surface 21 is zigzag. That is, 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 on the projection plane 21 so as to form, for example, a rectangle (including a square). As described above, in the drawing area 142, the vertical intervals between the adjacent drawing lines 141 are constant for the odd-numbered drawing lines 141 from the upper side, and similarly, the even-numbered drawing lines from the upper side. For 141, the vertical interval between adjacent drawing lines 141 is constant.

  In addition, when the laser light LL emitted from the light source unit 4 in the light emission state is scanned two-dimensionally with respect to the projection surface 21, the region on which the image on the projection surface 21 is drawn (the laser light LL is scanned). With regard to (region), it is possible to draw an image regardless of whether or not all parts are suitable for drawing, and the region is referred to as a “drawable region”. An area on the reflecting surface 125 corresponding to the drawable area (an area that may be used for drawing) is referred to as a “usable area”.

Next, the operation (action) of the image forming apparatus 1 when an image is drawn on the projection surface 21 of the screen 2 will be described.
First, as shown in FIG. 5, video data is input to the image forming apparatus main body 3. 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.

In the case where drawing of an image is started after a part of the video data is stored in the video data storage unit 81, it is preferably at least one frame, more preferably two frames or more (for example, two frames). ) Is stored in the video data storage unit 81, and then image drawing is started.
The drawing timing generation unit 83 generates drawing timing information, and the drawing timing information is sent to the video data calculation unit 82. The drawing timing information includes drawing timing information and the like.

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 instruction 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.

Based on the angle information of the mirror 121 input from the angle detection unit 13, the angle instruction unit 86 supplies drive data to the drive unit 124 of the galvano mirror 12 so that the angular velocity of the mirror 121 becomes a predetermined value (a constant value). Is sent out. The driving unit 124 drives the motor 122 based on the driving data, and thereby the angular velocity of the mirror 121 becomes the predetermined value.
In addition, the swing angle instruction unit 85 determines the swing angle of the movable plate 511a based on the information on the swing angle of the movable plate 511a input from the angle detection unit 52 so that the swing angle of the movable plate 511a becomes a predetermined value (a constant value). Drive data is sent to the drive means 517. Based on the driving data, the driving unit 517 applies a voltage to the coil 515 to cause a current to flow, thereby generating a predetermined magnetic field. Thereby, the deflection angle of the movable plate 511a becomes the predetermined value. In this way, the drive of the galvanometer mirror 12 is controlled so that the angular velocity of the mirror 121 is always a constant value, and the drive of the actuator 51 is controlled so that the deflection angle of the movable plate 511a is always a constant value, The laser beam LL is sequentially scanned on each drawing line 141 in the drawing area 142 to draw an image.
As described above, for each frame, for example, drawing is started from the upper left, and drawing is performed zigzag to the lower right.

Next, the shape of the reflecting surface 125 of the mirror 121 will be described in more detail with reference to FIG.
First, as shown in FIG. 7C, a cross-section perpendicular to the direction (y-axis) on the reflection surface 125 corresponding to the vertical direction (cross-section along the line BB in FIG. 7) (hereinafter “ The curvature (average value) of the reflecting surface 125 in the second cross section ”) changes along the y-axis. That is, as the cross section of the reflective surface 125, the second cross section is continuously taken along the y axis, and when the curvature of the reflective surface 125 in each second cross section is compared, the curvature is along the y axis. It has changed.

As a form of such a reflecting surface 125, the reflecting surface 125 is, for example, a curved concave surface curved in a concave shape along the direction of the rotation center axis Ja and a convex shape along the direction of the rotation center axis Ja. And the case of having one or both of the curved convex surface portions curved in the above manner.
In this case, in the curved concave surface portion of the reflective surface 125, the curvature of the curved concave surface portion in the second cross section changes along the y-axis. That is, on the curved concave surface corresponding to the vertical position where the distance in the vertical direction from the image forming apparatus main body 3 (image forming apparatus 1) is the shortest among the regions corresponding to the curved concave surface of the reflecting surface 125 in the drawing region 142. The curvature gradually increases from the position at the position toward the position on the curved concave surface corresponding to the position in the vertical direction having the longest vertical distance from the image forming apparatus main body 3.

  Further, in the curved convex surface portion of the reflecting surface 125, the curvature of the curved convex surface portion in the second cross section changes along the y axis. That is, on the curved convex surface corresponding to the vertical position where the vertical distance from the image forming apparatus main body 3 (image forming apparatus 1) is the longest among the regions corresponding to the curved convex surface of the reflecting surface 125 in the drawing region 142. The curvature gradually increases from the position at the position toward the position on the curved convex surface corresponding to the position in the vertical direction where the vertical distance from the image forming apparatus main body 3 is the shortest.

Further, as shown in FIG. 7B, reflection at a cross section (cross section taken along the line AA in FIG. 7) perpendicular to the rotation center axis Ja (hereinafter also referred to as “first cross section”). The curvature of the surface 125 changes along the reflective surface 125.
As a form of such a reflective surface 125, for example, the reflective surface 125 includes a curved concave surface portion curved in a concave shape along the y-axis direction, and a curved convex surface portion curved convexly along the y-axis direction. The case where it has either one or both is mentioned.

  In this case, in the curved concave surface portion of the reflecting surface 125, the curvature of the curved concave surface portion in the first cross section changes along the curved concave surface. That is, on the curved concave surface corresponding to the vertical position where the distance in the vertical direction from the image forming apparatus main body 3 (image forming apparatus 1) is the longest among the areas corresponding to the curved concave surface of the reflecting surface 125 in the drawing area 142. The curvature gradually increases from the position at the position toward the position on the curved concave surface corresponding to the vertical position where the vertical distance from the image forming apparatus main body 3 is the shortest.

  Further, in the curved convex surface portion of the reflecting surface 125, the curvature of the curved convex surface portion in the first cross section changes along the curved convex surface. That is, on the curved convex surface corresponding to the vertical position where the vertical distance from the image forming apparatus main body 3 (image forming apparatus 1) is the shortest among the regions corresponding to the curved convex surface of the reflecting surface 125 in the drawing region 142. The curvature gradually increases from the position at the position toward the position on the curved convex surface corresponding to the position in the vertical direction having the longest vertical distance from the image forming apparatus main body 3.

Further, when the reflecting surface 125 has a curved concave surface portion and a curved convex surface portion, the region from the image forming apparatus main body 3 (image forming device 1) out of the region corresponding to the reflecting surface 125 in the drawing region 142. The part of the reflecting surface 125 corresponding to the position with the shorter distance in the vertical direction is the curved concave surface, and the part of the reflecting surface 125 corresponding to the longer position is the curved convex surface.
Next, the shape of the reflecting surface 125 of the mirror 121 is specified using mathematical expressions. That is, the angle formed by the normal 127 in each part of the reflecting surface 125 in the first cross section and the optical axis 71 of the laser beam LL (incident light) reflected by the light reflecting part 511e and incident on each part of the reflecting surface 125. (Angle) β (see FIG. 7) is shown, and a normal line 127 in each part of the reflecting surface 125 in the second section and a straight line extending in a direction on the reflecting surface 125 corresponding to the vertical direction ( An expression representing an angle (angle) γ (see FIG. 7) formed with a straight line 61 parallel to the y-axis described later is shown, and thereby the shape of the reflecting surface 125 is specified.

In the present embodiment, a case of oblique projection in which an image is projected from a diagonal direction on the projection surface 21 will be described. As for the shape of the reflection surface 125 in the first cross section, the case where the reflection surface 125 has a curved convex surface curved in a convex shape will be described.
First, as shown in FIG. 6, the vertical length (height) of the drawing area 142 on the projection surface 21 is D, the horizontal length (width) is W, and the mirror 121 in the drawing area 142 is The distance in the vertical direction between the portion closest to the reflecting surface 125 and the reflecting surface 125 is L (the Y-axis direction is “positive”), the distance between the reflecting surface 125 and the projection surface 21 is H, and the reflecting surface 125 and the light. Let h be the distance from the reflecting surface of the reflecting portion 511e. Further, as shown in FIG. 6, assuming the X axis and the Y axis orthogonal to each other, the coordinates of the current drawing position on the projection surface 21 are (X, Y) (−W / 2 ≦ X ≦ W / 2, 0 ≦ Y ≦ D). The Y-axis direction is the vertical direction, and the X-axis direction is the horizontal direction.

Also, the total number (vertical resolution) of the vertical drawing lines 141 in the drawing area 142 is Vres [line], and the rotation angle (angular velocity) of the mirror 121 when scanning the laser light LL on one drawing line 141 is ω. [Rad / line].
Further, as shown in FIG. 7, the length of the direction on the reflection surface 125 corresponding to the vertical direction of the use area 129, which is the area on the reflection surface 125 corresponding to the drawing area 142 (area used for drawing). It is assumed that (height) is d and the length (width) in the direction on the reflecting surface 125 corresponding to the horizontal direction of the use area 129 is w. Further, as shown in FIG. 7, on the reflection surface 125 side, the x-axis and y-axis orthogonal to each other corresponding to the X-axis and Y-axis are assumed, and the coordinates of the current drawing position on the projection surface 21 ( The coordinates on the reflection surface 125 corresponding to (X, Y) are set to (x, y). The y-axis direction is the direction on the reflecting surface 125 corresponding to the vertical direction, and the x-axis direction is the direction on the reflecting surface 125 corresponding to the horizontal direction. Further, FIG. 7 shows a use area 129 that is an area (area used for drawing) on the reflective surface 125 corresponding to the drawing area 142.

  Further, as shown in FIG. 14, an angle reference line 62 is set. In the first cross section, the angle reference line 62 transmits the laser beam LL in the horizontal direction so that it passes through the portion of the drawing region 142 where the vertical distance from the reflecting surface 125 of the mirror 121 is the shortest (near). When scanning (hereinafter also simply referred to as “recent distance scanning”), the vertical distance from the reflecting surface 125 of the mirror 121 in the drawing region 142 passes through the longest (far) part. When the laser beam LL is scanned in the horizontal direction (hereinafter also simply referred to as “at the farthest distance scan”), a portion on the reflection surface 125 (hereinafter simply referred to as “the farthest distance”). It is also referred to as a “part on the reflecting surface 125 corresponding to the time of scanning”) and a rotation center axis Ja.

Further, as shown in FIG. 7, the 0th line of the drawing line 141 is used as a reference line, the laser light LL is scanned on the nth line (n is an integer), and the mth dot (m is an integer). X ₀ = −w / 2), that is, the mirror 121 connects the portion on the reflection surface 125 corresponding to the farthest distance scanning on the angle reference line 62 and the rotation center axis Ja. The intersection (reflection point) Q of the optical axis 71 of the laser beam LL incident on the reflection surface 125 and the reflection surface 125 when the straight line 63 is rotated by an angle of nω from the state where the straight line 63 is positioned (during the closest distance scan). Is set to (x _m , y _n ). Incidentally, the intersection point Q is in fact, at any point on the locus of laser light LL scans the reflecting surface 125 on the n-th line, x _m varies in the range of -w / 2 of w / 2.

Then, the normal 127 of the part of the coordinate (x _m , y _n ) of the reflecting surface 125 and the optical axis of the laser beam LL incident on the part of the coordinate (x _m , y _n ) of the reflecting surface 125 in the first cross section. The angle (angle) formed with 71 is β, and the projection surface 21 forms the optical axis 72 of the reflected light of the laser beam LL at the position of the coordinates (x _m , y _n ) of the reflecting surface 125 in the first cross section. The angle (angle) is α. In addition, the normal 127 of the part of the coordinate (x _m , y _n ) of the reflective surface 125 in the second cross section and a straight line (parallel to the y axis) extending in the direction on the reflective surface 125 corresponding to the vertical direction. An angle (angle) formed with the straight line 61 is γ.
Under such conditions (premise), an angle (angle) γ formed by the normal 127 and the straight line 61 at the position of the coordinates (x _m , y _n ) of the reflecting surface 125 is expressed by the following formula (1). . Note that the angle in the counterclockwise direction in FIG.

Further, the optical axis 72 of the reflected light of the laser light LL at a site coordinate y _n of the reflecting surface 125, the angle (angle) alpha with the projection surface 21, represented by the following formula (2).

Therefore, the the normal 127 of the site coordinate _{y n} of the reflecting surface 125, the angle between the optical axis 71 of the laser beam LL entering the site coordinates _{y n} of the reflection surface 125 (angle) beta is the following formula ( 3).

Here, as shown in FIG. 7C, when the shape of the reflecting surface 125 in the second cross section is a concave curved shape, that is, when the shape of the reflecting surface 125 is a concave curved shape, FIG. Γ at the position shown in (c) is a positive angle.
On the other hand, as shown in FIG. 8C, when the shape of the reflective surface 125 in the second cross section is a convex curved shape, that is, when the shape of the reflective surface 125 is a convex curved surface shape, Γ at the position indicated by 8 (c) is a negative angle.
Although not shown, when the shape of the reflecting surface 125 in the second cross section is linear, γ is 0 °.

  Further, when the following formula (4) is satisfied, as shown in FIG. 9, the horizontal direction so that the vertical distance from the reflecting surface 125 of the mirror 121 in the drawing region 142 passes through the shortest (nearest) part. When the laser beam LL is scanned in the direction, the first part of the reflection surface 125 (hereinafter, also simply referred to as “part on the reflection surface 125 corresponding to the closest distance scan”) scanned with the laser beam LL. The shape of the cross section 2 is linear (planar). Further, as shown in FIG. 10, the shape of the reflecting surface 125 in the second cross section at the upper part in FIG. 10 with respect to the part on the reflecting surface 125 corresponding to the closest distance scan is the mirror in the drawing region 142. When the laser beam LL is scanned in the horizontal direction so that the vertical distance from the 121 reflecting surface 125 passes through the longest (far) part, the laser beam LL is scanned on the reflecting surface 125. It is a concave curve shape (curved surface shape) up to the part (part on the reflection surface 125 corresponding to the farthest distance scanning). The curvature of the reflecting surface 125 in the second cross section gradually increases from the portion on the reflecting surface 125 corresponding to the nearest distance scanning toward the portion on the reflecting surface 125 corresponding to the farthest distance scanning.

  When the following formula (5) is satisfied, the shape of the reflection surface 125 in the second cross section is the same as the shape on the reflection surface 125 corresponding to the farthest distance scanning from the portion on the reflection surface 125 corresponding to the nearest distance scanning. The curved surface shape (curved surface shape) is concave to the part, and the curvature of the reflecting surface 125 in the second cross section is the reflecting surface 125 corresponding to the farthest distance scanning from the part on the reflecting surface 125 corresponding to the nearest distance scanning. It gradually increases toward the upper part.

  Further, when the following formula (6) is satisfied, as shown in FIG. 12, the shape of the portion on the reflection surface 125 corresponding to the farthest distance scanning in the second cross section is linear (planar). . Further, as shown in FIG. 11, the shape of the reflecting surface 125 in the second cross section in the lower part in FIG. 11 than the part on the reflecting surface 125 corresponding to the nearest distance scanning corresponds to the nearest distance scanning. A convex curve shape (curved surface shape) is formed up to a portion on the reflecting surface 125. The curvature of the reflecting surface 125 in the second cross section gradually increases from the portion on the reflecting surface 125 corresponding to the farthest distance scanning toward the portion on the reflecting surface 125 corresponding to the nearest distance scanning.

  When the following expression (7) is satisfied, the shape of the reflection surface 125 in the second cross section is from the portion on the reflection surface 125 corresponding to the farthest distance scanning to the reflection surface 125 corresponding to the nearest distance scanning. Up to a portion, it is a convex curved shape (curved surface shape), and the curvature of the reflecting surface 125 in the second cross section is the reflecting surface corresponding to the nearest distance scanning from the portion on the reflecting surface 125 corresponding to the farthest distance scanning. There is a gradual increase toward the region above 125.

Further, when the following formula (8) is satisfied, as shown in FIG. 13, between the part on the reflecting surface 125 corresponding to the nearest distance scanning and the part on the reflecting surface 125 corresponding to the farthest distance scanning. The shape in the 2nd cross section of the site | part 128 located is linear (planar shape).
In addition, the shape of the reflecting surface 125 in the second cross section of the portion above the portion 128 in FIG. 13 is a concave curved shape (curved surface shape) up to the portion on the reflecting surface 125 corresponding to the farthest distance scanning. The curvature of the reflecting surface 125 in the second cross section gradually increases from the portion 128 toward the portion on the reflecting surface 125 corresponding to the farthest distance scanning.
Further, the shape of the reflecting surface 125 in the second cross section at the lower part in FIG. 13 with respect to the part 128 is a convex curved shape (curved surface shape) up to the part on the reflecting surface 125 corresponding to the nearest distance scanning. The curvature of the reflection surface 125 in the second cross section gradually increases from the portion 128 toward the portion on the reflection surface 125 corresponding to the closest distance scan.

The Y coordinate (Y _base ) of the part 128 satisfies the following formula (9) and is a positive number smaller than D (0 <Y _base <D).

As described above, according to the image forming apparatus 1, since the fluctuation width of the laser light LL in the light emitting state is constant along the vertical direction, the non-drawing area can be made very small. Thereby, it is possible to prevent the trapezoidal distortion of the image while increasing the time aperture ratio.
Further, complicated control on the mirror 121 is not required, and the distortion of the image in the vertical direction can be prevented easily and reliably.

Since the time aperture ratio can be increased, the drawing time per pixel can be lengthened, and thereby the luminance per pixel can be increased. In addition, the modulation speed of the laser light sources 41r, 41g, and 41b can be lowered, the modulation speed of the laser light sources 41r, 41g, and 41b can be prevented from being insufficient, and an image can be reliably drawn. it can.
Further, by specifying the shape of the reflecting surface 125 of the mirror 121, trapezoidal distortion and vertical distortion of the image are prevented, so that the configuration is simple and the number of parts can be reduced.

<Second Embodiment>
Next, a second embodiment of the image forming apparatus of the present invention will be described.
FIG. 16 is a diagram illustrating a second embodiment of the image forming apparatus according to the present invention, in which FIG. 16A is a side view, and FIG. 16B is a front view when a projection surface is targeted. . 17 is a diagram illustrating an example of the galvanometer mirror of the image forming apparatus illustrated in FIG. 16. FIG. 17A is a plan view, and FIG. 17B is a diagram in FIG. FIG. 17C is a cross-sectional view taken along the line E-E, and FIG. 17C is a cross-sectional view taken along the line F-F in FIG. 18 is a view showing another example of the galvanometer mirror of the image forming apparatus shown in FIG. 16, FIG. 18 (a) is a plan view, and FIG. 18 (b) is a view shown in FIG. 18 (a). FIG. 18C is a cross-sectional view taken along the line H-H in FIG. 18A.
In the following, for convenience of explanation, the upper side in FIGS. 16 to 18 is referred to as “upper”, the lower side is referred to as “lower”, the right side is referred to as “right”, and the left side is referred to as “left”.

Hereinafter, the image forming apparatus according to the second embodiment will be described with a focus on differences from the first embodiment described above, and description of similar matters will be omitted.
As shown in FIG. 16, in the second embodiment, a case of normal projection in which an image is projected from the front direction on the projection surface 21 will be described.
The image forming apparatus 1 that performs normal projection is the same as the image forming apparatus 1 that performs oblique projection shown in FIG. ) It can be realized by rotating it 90 ° clockwise.

First, as shown in FIG. 16, it passes through the intersection P between the perpendicular 211 drawn from the reflection surface 125 of the mirror 121 to the projection surface 21 and the projection surface 21 and the center of the drawing area 142 on the projection surface 21 in the vertical direction. The distance in the vertical direction from the center line M extending in the horizontal direction is L1. Further, as shown in FIG. 17, the optical axis 72 of the reflected light of the laser light LL at a site coordinate y _n of the reflecting surface 125 of the first section, a perpendicular 211 drawn on the projection plane 21 from the reflecting surface 125 Let α be the angle formed by.
The α is represented by the following formula (10). Note that the angle α when the optical axis 72 of the reflected light is located on the upper side in FIG. 17B from the intersection P is “positive”, and the angle α when the optical axis 72 is located on the lower side in FIG. “Negative”.

Thus, a portion of the normal 127 of the coordinate _{y n} of the reflecting surface 125 of the first section, the angle between the optical axis 71 of the laser beam LL entering the site coordinates _{y n} of the reflection surface 125 (angle) beta is Is represented by the following formula (11).

Further, γ is the same as the above formula (1), and as shown in FIG. 17C, when the shape of the reflecting surface 125 in the second cross section is a concave curved shape, that is, the reflecting surface 125. Is a concave curved surface shape, γ at the position shown in FIG. 17C is a positive angle. Further, as shown in FIG. 18C, when the shape of the reflecting surface 125 in the second cross section is a convex curved shape, that is, when the shape of the reflecting surface 125 is a convex curved surface shape, Γ at the position shown in 18 (c) is a negative angle. Although not shown, when the shape of the reflecting surface 125 in the second cross section is a straight line, γ is 0 °.
Here, when L1 = 0 and L = −D / 2, normal projection perpendicular to the projection surface 21 is obtained.

  Further, when H = (W−w) · h / w holds, the optical axis of the laser beam LL in the drawing region 142 is the projection plane in a side view (when viewed from the direction of the rotation center axis Ja). When the laser beam LL is scanned in the horizontal direction so as to pass through a region perpendicular to the region 21, the region on the reflection surface 125 on which the laser beam LL is scanned (hereinafter simply referred to as “corresponding to center scanning”). In other words, the shape of the portion on the reflecting surface 125 corresponding to the closest distance scanning is a straight line (planar).

Also by such 2nd Embodiment, the effect similar to 1st Embodiment can be exhibited.
The image forming apparatus 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 unit 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.
In the above-described embodiment, the image forming apparatus that draws an image on the screen has been described. However, the present invention is not limited to this. For example, the image forming apparatus may draw an image on a wall or the like. .

In the present invention, the screen may not be included as a component.
Further, the present invention provides an apparatus configured to view the reflected light of the light projected on the projection surface and an apparatus configured to view the transmitted light of the light projected onto the projection surface, for example, transmitted / diffused light using a light diffusion plate or the like. It can be applied to any device that is configured to view
In the embodiment, the deflection angle around the rotation center axis of the first reflecting surface is constant. However, in the present invention, the deflection angle of the first reflecting surface is not constant. In this case as well, the shape of the second reflecting surface is such that when the light emitted from the light emitting portion is scanned two-dimensionally with respect to the projection surface in the light emitting state, The runout width in the direction 1 is a curved surface shape that is constant along the second direction.

  In the embodiment, the angular velocity of the second reflecting surface is constant. However, in the present invention, the angular velocity of the second reflecting surface may not be constant. Also in this case, the shape of the second reflecting surface is the same as the second direction on the projection surface when the light emitted from the light emitting portion is scanned two-dimensionally with respect to the projection surface in the light emitting state. The curved surface shape is such that the intervals between the drawn lines are constant.

  Further, in the above-described embodiment, the optical scanning unit uses an actuator that is resonantly driven (operated using resonance) as the first direction scanning unit that scans in the first direction, and uses the second direction. Although the galvanometer mirror is used as the second direction scanning unit that scans in the second direction, the present invention is not limited to this. For example, a polygon mirror, which is driven by resonance, is used as the second direction scanning unit instead of the galvanometer mirror. A form of actuator or the like may be used. In addition, when using the actuator of the form driven by resonance as a 2nd direction scanning part, it is preferable to shorten the distance of a 1st reflective surface and a 2nd reflective surface.

Further, the present invention may be configured to perform vertical scanning in each of the forward path and the backward path, and to draw an image by performing horizontal scanning in each of the forward path and the backward path in each of the vertical scanning. .
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 ... Image forming apparatus 2 ... Screen 21 ... Projection surface 211 ... Perpendicular 3 ... Image forming apparatus main body 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 section 51 ... Actuator 511 ... Base 511a ... Movable plate 511b ...... Supporting part 511c, 511d ...... Connecting part 511e ...... Light reflecting part 512 ...... Spacer member 513 ...... Opposing substrate 514 ...... Permanent magnet 515 ...... Coil 516 ...... Voltage applying means 517 ...... Driving means 52 ...... ... Angle detection means 521 …… Piezoelectric element 522 …… Electromotive force detection unit 23 …… Angle detection unit 300 …… Scan projector 61, 63 …… Straight line 62 …… Angle reference line 71, 72 …… Optical axis 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 instruction unit 86 …… Angle instruction unit 12 …… Galvano mirror 121 …… Mirror 122 …… Motor 123 …… Drive circuit 124 …… Drive means 125 ...... Reflecting surface 127 ...... Normal 128 ...... Part 129 ...... Used area 13 ...... Angle detection means 131 ...... Encoder 132 ...... Angle detector 141 ...... Drawing line 142 ...... Drawing area 143 ...... Drawable area LL, RR, GG, BB ... Laser beam J, Ja ... Rotation center axis

Claims (16)

The projection surface is configured to draw an image by scanning light,
A light emitting portion for emitting light;
A first reflection surface that is rotatably provided to reflect light emitted from the light emitting portion, and a rotation member that is capable of reflecting light reflected by the first reflection surface toward the projection surface. The second reflecting surface, and by rotating each of the first reflecting surface and the second reflecting surface, the light emitted from the light emitting unit is directed to the projection surface. An optical scanning unit that scans two-dimensionally by scanning in a first direction and scanning in a second direction orthogonal to the first direction at a scanning speed slower than the scanning speed in the first direction; With
When viewed from the direction of the rotation center axis of the second reflecting surface, the second reflecting surface rotates, so that the light reflected by the first reflecting surface is directed to the second reflecting surface. The irradiation position is configured to change,
The second reflection surface is in a light emitting state in which light is emitted from the light emitting unit, and when the light emitted from the light emitting unit is scanned two-dimensionally with respect to the projection surface, The fluctuation width of the light in the first direction is constant along the second direction, and the interval between the drawing lines arranged along the second direction on the projection plane is constant. An image forming apparatus having a curved shape. The shape of the first reflecting surface is a plane,
The image forming apparatus according to claim 1, wherein a deflection angle of the first reflecting surface about a rotation center axis is constant.   The image forming apparatus according to claim 1, wherein an angular velocity of the second reflecting surface is constant.   4. The image forming apparatus according to claim 1, wherein the second reflecting surface is provided at a position separated from a rotation center axis of the second reflecting surface. 5.   The curvature of the said 2nd reflective surface in the cross section perpendicular | vertical with respect to the rotation center axis | shaft of a said 2nd reflective surface is changing along this 2nd reflective surface. The image forming apparatus described in 1. The second reflecting surface has a curved concave surface portion curved in a concave shape,
The image according to any one of claims 1 to 5, wherein a curvature of a portion of the curved concave surface in a cross section perpendicular to the rotation center axis of the second reflecting surface changes along the curved concave surface. Forming equipment. When light emitted from the light emitting portion is scanned two-dimensionally with respect to the projection surface in a light emitting state where light is emitted from the light emitting portion, the second reflecting surface is In addition, the light reflected by the first reflecting surface is configured to be scanned two-dimensionally,
The curve corresponding to the position in the second direction having the longest distance in the second direction from the image forming apparatus among the areas corresponding to the curved concave surface in the drawing area for drawing the image on the projection surface. The curvature gradually increases from the position on the concave surface toward the position on the curved concave surface corresponding to the position in the second direction with the shortest distance in the second direction from the image forming apparatus. The image forming apparatus according to claim 6. The second reflecting surface has a curved convex surface curved in a convex shape,
The image according to any one of claims 1 to 7, wherein a curvature of a portion of the curved convex surface in a cross section perpendicular to the rotation center axis of the second reflecting surface changes along the curved convex surface. Forming equipment. When light emitted from the light emitting portion is scanned two-dimensionally with respect to the projection surface in a light emitting state where light is emitted from the light emitting portion, the second reflecting surface is In addition, the light reflected by the first reflecting surface is configured to be scanned two-dimensionally,
Of the region corresponding to the curved convex surface in the drawing region for drawing the image on the projection surface, the curve corresponding to the position in the second direction with the shortest distance in the second direction from the image forming apparatus. The curvature gradually increases from the position on the convex surface toward the position on the curved convex surface corresponding to the position in the second direction with the longest distance in the second direction from the image forming apparatus. The image forming apparatus according to claim 8.   The curvature of the second reflecting surface in a cross section perpendicular to the direction on the second reflecting surface corresponding to the second direction is the second reflecting surface corresponding to the second direction. The image forming apparatus according to claim 1, wherein the image forming apparatus changes along the above direction. The second reflecting surface has a curved concave surface portion curved in a concave shape,
The curvature of the curved concave surface in a cross section perpendicular to the direction on the second reflecting surface corresponding to the second direction is on the second reflecting surface corresponding to the second direction. The image forming apparatus according to claim 1, wherein the image forming apparatus changes in a direction along the line. When light emitted from the light emitting portion is scanned two-dimensionally with respect to the projection surface in a light emitting state where light is emitted from the light emitting portion, the second reflecting surface is In addition, the light reflected by the first reflecting surface is configured to be scanned two-dimensionally,
The curve corresponding to the position in the second direction with the shortest distance in the second direction from the image forming apparatus among the areas corresponding to the curved concave surface in the drawing area for drawing the image on the projection surface. The curvature gradually increases from the position on the concave surface toward the position on the curved concave surface corresponding to the position in the second direction with the longest distance in the second direction from the image forming apparatus. The image forming apparatus according to claim 11. The second reflecting surface has a curved convex surface curved in a convex shape,
The curvature of the curved convex surface in a cross section perpendicular to the direction on the second reflecting surface corresponding to the second direction is on the second reflecting surface corresponding to the second direction. The image forming apparatus according to claim 1, wherein the image forming apparatus changes in a direction along the line. When light emitted from the light emitting portion is scanned two-dimensionally with respect to the projection surface in a light emitting state where light is emitted from the light emitting portion, the second reflecting surface is In addition, the light reflected by the first reflecting surface is configured to be scanned two-dimensionally,
The curve corresponding to the position in the second direction with the longest distance in the second direction from the image forming apparatus among the areas corresponding to the curved convex surface in the drawing area for drawing the image on the projection surface. The curvature gradually increases from the position on the convex surface toward the position on the curved convex surface corresponding to the position in the second direction with the shortest distance in the second direction from the image forming apparatus. The image forming apparatus according to claim 9. The optical scanning unit is rotatably provided, and connects the movable plate having the first reflecting surface, a support unit that rotatably supports the movable plate, and the movable plate and the support unit. An actuator comprising a connecting portion and a driving means for rotating the movable plate;
The image forming apparatus according to claim 1, further comprising a galvanometer mirror having the second reflecting surface.   The image forming apparatus according to claim 1, further comprising a screen having the projection surface.

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