JP2014228817A - Image display device and head-mounted display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device and a head-mounted display which can be miniaturized.SOLUTION: An image display device 1 includes: laser light sources 21R, 21G and 21B for emitting light; a photosynthesis part 23 for synthesizing the light emitted from the laser light sources 21R, 21G and 21B; an optical scanning part 4 for scanning the light synthesized by the photosynthesis part 23; and a frame 7 loaded with the laser light sources 21R, 21G and 21B, the photosynthesis part 23 and the optical scanning part 4, and mounted on a head H of an observer. An optical path until the light emitted from the laser light sources 21R, 21G and 21B is made incident to the optical scanning part 4 is disposed on a surface F as the same virtual plane, and the surface F follows the vertical direction (X-axial direction) of the head H when the frame 7 is mounted on the head H.

Description

  The present invention relates to an image display device and a head mounted display.

An image display device that displays an image by two-dimensionally scanning light from a light source is known (see, for example, Patent Document 1).
For example, an image display device according to Patent Document 1 includes three semiconductor lasers, three coupling lenses that respectively convert laser beams emitted from the three semiconductor lasers into substantially parallel beams, and laser beams that have been converted into parallel beams. Two dichroic mirrors that synthesize the color, a condensing lens on which the color-synthesized laser beam is incident, a flat mirror that deflects the laser beam that has passed through the condensing lens, and a laser beam that is deflected by the flat mirror And a beam scanning unit for two-dimensionally scanning.

  In the image display device according to Patent Document 1, the optical path until the laser beam deflected by the plane mirror enters the beam scanning unit is the optical path until the laser beam emitted from each semiconductor laser enters the plane mirror. It is out of the plane containing. For this reason, the thickness of the entire optical system from each semiconductor laser to the beam scanning unit is increased, resulting in a problem that the entire image display apparatus is increased in size.

Japanese Unexamined Patent Publication No. 2011-154344

  An object of the present invention is to provide an image display device and a head mounted display that can be miniaturized.

Such an object is achieved by the present invention described below.
The image display device of the present invention includes a plurality of light source units that emit light,
A light combining unit that combines light emitted from the plurality of light sources;
An optical scanning unit that scans the light combined by the light combining unit;
The light source unit, the light combining unit, and the optical scanning unit are mounted, and the frame is mounted on the observer's head,
The optical path until the light emitted from the light source unit enters the optical scanning unit is on the same virtual plane,
The virtual plane is characterized by being along the vertical direction of the head when the frame is attached to the head.
According to such an image display device, it is possible to reduce the thickness of a structure (unit) including a plurality of light source units, a light combining unit, and an optical scanning unit.
Such a thinned structure can be arranged along a direction perpendicular to the thickness direction of the frame. As a result, the entire image display apparatus can be reduced in size.

In the image display device according to the aspect of the invention, it is preferable that the image display apparatus includes a housing that is supported by the frame and that houses the light source unit, the light combining unit, and the light scanning unit.
Thereby, a light source part, a photosynthesis part, and an optical scanning part can be protected. In addition, the positional relationship among the light source unit, the light combining unit, and the light scanning unit can be stably fixed by the housing or a member fixedly provided on the case. Furthermore, the light source unit, the light combining unit, and the optical scanning unit can be unitized together with the housing, and can be attached to and detached from the frame.

In the image display device according to the aspect of the invention, it is preferable that the housing is rotatable with respect to the frame.
Thereby, the position where the light (scanning light) scanned by the optical scanning unit is projected can be adjusted.
In the image display device of the present invention, it is preferable that the casing has a flat shape along the virtual plane.
Accordingly, the light source unit, the light combining unit, and the optical scanning unit can be accommodated in the thinned casing.

In the image display device of the present invention, the frame includes a front part and a temple part connected to the front part,
It is preferable that the light source unit, the light combining unit, and the optical scanning unit are mounted on the temple unit.
Thereby, the size reduction of the eyeglass-type image display device can be achieved.

In the image display device according to the aspect of the invention, the light scanning unit swings around each of the first axis and the second axis that intersect with each other, and reflects the light combined by the light combining unit. It is preferable to have a light reflecting plate provided with a reflecting surface.
Thereby, compared with the case where separate light reflecting plates are provided around the first axis and the second axis, the optical scanning unit can be reduced in size.

In the image display device according to the aspect of the invention, the optical scanning unit includes a base that swings around the first axis and the second axis, and a spacer that connects the base and the light reflecting plate. And
The light reflecting surface is preferably perpendicular to the virtual plane when the optical scanning unit is not driven.
Thereby, the dimension of the direction along the plane containing the 1st axis | shaft and 2nd axis | shaft of an optical scanning part can be made small. Then, by arranging the light scanning unit so that the light reflecting unit is perpendicular to the virtual plane, the thickness along the direction perpendicular to the virtual plane of the image display device can be reduced.

In the image display device according to the aspect of the invention, the optical scanning unit supports a frame body portion provided so as to surround the base portion, and the base portion is swingably supported around the first axis with respect to the frame body portion. Preferably, the first shaft portion and the second shaft portion that supports the frame body portion so as to be swingable about the second shaft are provided.
As a result, while the dimensions in the direction along the plane including the first axis and the second axis of the optical scanning unit are reduced, the oscillations around the first axis and the second axis of the light reflecting plate are reduced. The moving angle can be increased.

In the image display device according to the aspect of the invention, the optical scanning unit includes a permanent magnet provided in the frame body part, and a coil that is disposed to face the frame body part and generates a magnetic field that acts on the permanent magnet. It is preferable.
This increases the thickness along the direction perpendicular to the first axis and the second axis of the optical scanning unit, but the width along the plane including the first axis and the second axis of the optical scanning unit. Can be reduced.

The image display device of the present invention is an image display device used by being worn on the observer's head,
A plurality of light source units that emit light;
A light combining unit that combines light emitted from the plurality of light sources;
An optical scanning unit that scans the light combined by the light combining unit,
The optical path until the light emitted from the light source unit enters the optical scanning unit is on the same virtual plane along the side surface or the front surface of the head at the time of use.
According to such an image display device, it is possible to reduce the thickness of a structure (unit) including a plurality of light source units, a light combining unit, and an optical scanning unit.
The thinned structure can be arranged along a direction perpendicular to the thickness direction of the image display device. As a result, the entire image display apparatus can be reduced in size.

The head-mounted display of the present invention includes a plurality of light source units that emit light,
A light combining unit that combines light emitted from the plurality of light sources;
An optical scanning unit that scans the light combined by the light combining unit;
The light source unit, the light combining unit, and the optical scanning unit are mounted, and the frame is mounted on the observer's head,
The optical path until the light emitted from the light source unit enters the optical scanning unit is on the same virtual plane,
The virtual plane is characterized by being along the vertical direction of the head when the frame is attached to the head.

According to such a head mounted display, it is possible to reduce the thickness of a structure (unit) including a plurality of light source units, a light combining unit, and an optical scanning unit.
Such a thinned structure can be arranged along a direction perpendicular to the thickness direction of the frame. As a result, the entire head mounted display can be reduced in size.

It is a figure which shows schematic structure of the image display apparatus (head mounted display) which concerns on embodiment of this invention. (A) is a front view of the image display apparatus shown in FIG. 1, (b) is the sectional view on the AA line in (a). It is a figure explaining the image display unit and reflection member of the image display apparatus shown in FIG. It is a schematic plan view of the image display unit of the image display apparatus shown in FIG. It is a figure which shows the cross section of the laser beam which the laser light source of the image display unit shown in FIG. 4 radiate | emits. It is a side view of the image display unit shown in FIG. It is a top view which shows the optical scanning part (optical scanner) which the image display unit shown in FIG. 4 has. It is sectional drawing of the optical scanner shown in FIG. It is a block diagram of the voltage application part which the optical scanner shown in FIG. 8 has. It is a figure which shows an example of the voltage generated in the 1st voltage generation part shown in FIG. 9, and a 2nd voltage generation part. It is a figure which shows the difference of the drawable area | region by arrangement | positioning of an optical scanner.

Hereinafter, preferred embodiments of an image display device and a head mounted display of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a diagram showing a schematic configuration of an image display device (head mounted display) according to an embodiment of the present invention, FIG. 2A is a front view of the image display device shown in FIG. 1, and FIG. FIG. 3 is a cross-sectional view taken along line AA in FIG.
In FIGS. 1 and 2, for convenience of explanation, the X axis, the Y axis, and the Z axis are illustrated as three axes orthogonal to each other, and the tip side of the illustrated arrow is indicated by “+ (plus)”. The end side is “− (minus)”. A direction parallel to the X axis is referred to as “X axis direction”, a direction parallel to the Y axis is referred to as “Y axis direction”, and a direction parallel to the Z axis is referred to as “Z axis direction”.
Here, with respect to the X axis, the Y axis, and the Z axis, when the image display device 1 described later is mounted on the head H of the observer, the X axis direction is the vertical direction of the head H, and the Z axis direction is the head H. The left-right direction and the Y-axis direction are set to be the front-rear direction of the head H. Note that the X-axis direction is a straight line orthogonal to a straight line connecting the eyes of the observer when viewed from the front of the observer.

An image display device 1 shown in FIG. 1 is a see-through head-mounted display (head-mounted image display device). In other words, the image display device 1 is used by being worn on the observer's head H, and allows the observer to visually recognize an image based on a virtual image superimposed on an external image.
The image display device 1 includes a frame 7 having an appearance like glasses worn on the head H, a reflective member 81, a transparent member 82, and an image display unit 10 supported by the frame 7.

  In such an image display device 1, when the frame 7 is mounted on the head H (hereinafter also referred to as “in use”), an observer can visually recognize an external field image via the reflecting member 81 and the transparent member 82. The image display unit 10 irradiates the reflecting member 81 with scanning light (hereinafter, also simply referred to as “scanning light”) scanned two-dimensionally by the light, and the scanning light reflected by the reflecting member 81 is applied to the right eye of the observer. By projecting onto EY, an image that can be visually recognized by an observer is formed as a virtual image.

  In the present embodiment, an example in which the image display unit 10 is provided only on the right side of the frame 7 and only a virtual image for the right eye is formed will be described, but the left side of the frame 7 is used in combination with the image display unit 10. By providing a unit having the same configuration as the image display unit 10, a virtual image for the left eye may be formed together with the virtual image for the right eye. Further, instead of the image display unit 10, a unit having the same configuration as that of the image display unit 10 may be provided on the left side of the frame 7, so that only a virtual image for the left eye may be formed. Further, when forming a virtual image only on the right side and only on the left side, the transparent member 82 may be omitted.

Hereinafter, each part of the image display device 1 will be sequentially described in detail.
(flame)
As shown in FIGS. 1 and 2A, the frame 7 has a function of supporting the reflecting member 81, the transparent member 82, and the image display unit 10.
As shown in FIG. 1, the frame 7 has a shape like a spectacle frame. That is, the frame 7 includes a front portion 72 that supports the nose pad portion 71, a pair of temple portions (vine portions) 73 that are connected to the front portion 72 and come into contact with the ears EA of the observer, and each temple portion 73. And a modern part 74 that is the end opposite to the front part 72.

The nose pad portion 71 abuts on the nose NS of the observer when in use, and supports the image display device 1 with respect to the head H of the observer.
The nose pad portion 71 is configured to be able to adjust the position of the frame 7 with respect to the head H in use.
The front portion 72 includes a pair of left and right rim portions 75 and a bridge portion 76 provided between the pair of rim portions 75. The right rim portion 75 supports the reflecting member 81, and the left rim portion 75 supports the transparent member 82.

Further, as shown in FIG. 2, one temple portion 73 on the right side of the pair of temple portions 73 supports the image display unit 10. Thereby, laser light sources 21R, 21G, and 21B, a light combining unit 23, and a light scanning unit 4 included in the image display unit 10 described later are mounted on the frame 7.
Note that the image display unit 10 may be supported by the front portion 72. Further, each temple portion 73 may be formed integrally with the front portion 72 or may be formed separately from the front portion 72. The shape of the frame 7 is not limited to that shown in the drawing as long as it can be attached to the head H of the observer.

(Reflective member and transparent member)
As shown in FIGS. 1 and 2A, the reflecting member 81 is attached to the rim portion 75 on the right side of the frame 7 described above. The transparent member 82 is attached to the left rim 75 of the frame 7 described above.
That is, the reflecting member 81 is disposed so as to be positioned in front of one (right side) eye EY of the observer when in use. In addition, the transparent member 82 is disposed so as to be positioned in front of the other (left side) eye EY of the observer during use.

Each of the reflecting member 81 and the transparent member 82 has transparency to visible light. Thereby, the observer can visually recognize external light through the reflecting member 81 and the transparent member 82.
Further, the reflecting member 81 is reflective to the light (scanning light) emitted from the image display unit 10. More specifically, the reflecting member 81 has a function of reflecting light emitted from the image display unit 10 toward the eye EY of the observer at the time of use. Thereby, the observer can visually recognize the image by the image display unit 10.

  In the present embodiment, the reflecting member 81 is a half mirror. Thereby, the reflection member 81 can reflect the light (scanning light) emitted from the image display unit 10 and can transmit external light from the outside of the reflection member 81 toward the observer's eye EY during use. . Therefore, the observer can visually recognize the virtual image (image) formed by the scanning light while visually recognizing the external image. That is, a see-through type head mounted display can be realized.

Although not shown, the reflecting member 81 includes, for example, a transparent substrate (translucent portion) that transmits external light and a diffraction grating that is supported by the transparent substrate and reflects scanning light from the image display unit 10. Accordingly, the diffraction grating can have various optical characteristics, the number of parts of the optical system can be reduced, and the degree of design freedom can be increased. For example, by using a hologram element as the diffraction grating, the emission direction of the scanning light reflected by the reflecting member 81 can be adjusted. In addition, by providing the diffraction grating with a lens effect, the imaging state of the scanning light reflected by the reflecting member 81 can be adjusted.
Note that the reflecting member 81 is not limited to the above-described configuration, and for example, a transflective film formed of a metal thin film, a dielectric multilayer film, or the like may be formed on a transparent substrate. Further, the reflecting member 81 may not have transparency to visible light. In this case, it is preferable to arrange the reflecting member 81 at a position that does not obstruct the view of the observer.

In the present embodiment, the reflecting member 81 has a curved shape along the curvature of the frame 7. As a result, the reflecting member 81 can have a lens effect. Further, the design of the image display device 1 can be made excellent. The shape of the reflecting member 81 is determined according to the configuration and arrangement of the image display unit 10, the optical characteristics of the reflecting member 81, and the like, and is not limited to the illustrated one.
On the other hand, the transparent member 82 does not need to have light reflectivity, and may have a different configuration from the reflection member 81 as long as it has transparency to visible light, or is configured in the same manner as the reflection member 81. May be. The transparent member 82 may be omitted.

(Image display unit)
Next, the image display unit 10 will be described.
3 is a diagram for explaining the image display unit and the reflecting member of the image display device shown in FIG. 1, FIG. 4 is a schematic plan view of the image display unit of the image display device shown in FIG. 1, and FIG. FIG. 6 is a side view of the image display unit shown in FIG. 4, and FIG. 6 is a side view of the laser beam emitted from the laser light source of the image display unit shown in FIG. 7 is a plan view showing an optical scanning unit (optical scanner) included in the image display unit shown in FIG. 4, and FIG. 8 is a cross-sectional view of the optical scanner shown in FIG. FIG. 9 is a block diagram of a voltage application unit included in the optical scanner shown in FIG. 8, and FIG. 10 shows an example of voltages generated in the first voltage generation unit and the second voltage generation unit shown in FIG. FIG. FIG. 11 is a diagram illustrating a difference in the drawable area depending on the arrangement of the optical scanner.

3 to 6 and FIG. 11, for convenience of explanation, the X ′ axis, the Y ′ axis, and the Z ′ axis are illustrated as three axes that are orthogonal to each other. The “+ side” and the base end side are referred to as “− side”. A direction parallel to the X ′ axis is referred to as “X ′ axis direction”, a direction parallel to the Y ′ axis is referred to as “Y ′ axis direction”, and a direction parallel to the Z ′ axis is referred to as “Z ′ axis direction”. A plane parallel to both the X ′ axis and the Y ′ axis is referred to as an “X′Y ′ plane”.
Here, for convenience of explanation, the Z ′ axis coincides with the Z axis, and the X ′ axis and the Y ′ axis coincide with the X axis and the Y axis rotated by an angle α around the Z axis, respectively. The Z ′ axis may be inclined with respect to the Z axis, and the inclination angle is preferably 45 ° or less, and more preferably 30 ° or less.

As shown in FIG. 3, the image display unit 10 is attached to one of the temple portions 73 of the frame 7 described above, and emits scanning light obtained by scanning the drawing laser light LL toward the reflecting member 81.
As shown in FIG. 4, the image display unit 10 includes a drawing light source unit 2 that emits a drawing laser beam LL, an optical axis of the drawing laser beam LL, and a cross-sectional shape of the drawing laser beam LL. A prism (optical member) 3 that deforms the light, a light scanning unit 4 that scans the drawing laser beam LL that has passed through the prism 3, a detection unit 5 that detects the intensity of the drawing laser beam LL, and a drawing light source unit 2 And a control unit 6 for controlling the operation of the optical scanning unit 4 and a housing 9 for housing them.

Hereinafter, each part structure of the image display unit 10 is demonstrated sequentially.
(Light source unit for drawing)
As shown in FIG. 4, the drawing light source unit 2 includes red, green, blue, and laser light sources 21R, 21G, and 21B (light source units) for each color, and collimators provided corresponding to the laser light sources 21R, 21G, and 21B. Meter lenses 22R, 22G, and 22B and dichroic mirrors 23R, 23G, and 23B are provided.

<Light source part>
Each of the laser light sources 21R, 21G, and 21B has a light source and a drive circuit (not shown). The laser light source 21R emits red laser light RR, the laser light source 21G emits green laser light GG, and the laser light source 21B emits blue laser light BB. The laser beams RR, GG, and BB are emitted corresponding to the drive signals transmitted from the control unit 6, and are converted into parallel light or substantially parallel light by the collimator lenses 22R, 22G, and 22B.

In the present embodiment, the laser light sources 21R, 21G, and 21B are arranged in the −Y′-axis direction in the order of the laser light source 21R, the laser light source 21B, and the laser light source 21G, and the left side (−X ′) of the housing 9 in FIG. It is arranged at the end on the axial direction side. The laser light sources 21R, 21G, and 21B emit laser beams RR, GG, and BB in the + X ′ axis direction, respectively. With this arrangement, the laser light sources 21R, 21G, and 21B can be arranged in a smaller space. Therefore, the image display unit 10 (housing 9) can be downsized. The arrangement of the laser light sources 21R, 21G, and 21B is not limited to the above arrangement.
As such laser light sources 21R, 21G, and 21B, for example, a semiconductor laser such as an edge emitting semiconductor laser or a surface emitting semiconductor laser can be used. By using a semiconductor laser, the laser light sources 21R, 21G, and 21B can be downsized.

  When semiconductor lasers are used as the laser light sources 21R, 21G, and 21B, generally, the contour shape of the light intensity distribution of the laser light RR, GG, and BB emitted from the laser light sources 21R, 21G, and 21B (so-called FFP) : Far Field Pattern) is substantially elliptical. In the following, the “cross-sectional shape” of the laser beams RR, GG, and BB is used in the same meaning as the “contour shape of the light intensity distribution” of the laser beams RR, GG, and BB. That is, in this case, it can be said that the laser beams RR, GG, and BB emitted from the laser light sources 21R, 21G, and 21B each have a substantially elliptical cross-sectional shape. Here, the cross-sectional shape is a shape in a cross section perpendicular to the optical axes of the laser beams RR, GG, and BB.

  As shown in FIG. 5, the laser light sources 21R, 21G, and 21B emit laser beams RR, GG, and BB each having a substantially elliptical (oval) cross-sectional shape. In these laser light sources 21R, 21G, and 21B, the major axis of the ellipse formed by the cross-sections of the laser beams RR, GG, and BB almost coincides with the Z ′ axis, and the minor axis almost coincides with the Y ′ axis. Is disposed in the housing 9. In other words, each of the laser light sources 21R, 21G, and 21B has an emission angle in the Z′-axis direction (normal direction of the X′Y ′ plane) in the Y′-axis direction (in-plane direction of the X′Y ′ plane). Laser beams RR, GG, and BB larger than the radiation angle are emitted. Thereby, for example, compared to the case opposite to the above (when the radiation angle in the Z′-axis direction is smaller than the radiation angle in the Y′-axis direction), the three laser light sources 21R, 21G, and 21B arranged in the Y′-axis direction are used. Can be arranged at a narrow pitch. Therefore, it is possible to suppress the spread of the housing 9 in the X′Y ′ plane direction. Therefore, the image display unit 10 can be reduced in size.

  The laser beams RR, GG, and BB emitted from the laser light sources 21R, 21G, and 21B are each linearly polarized light. The laser beams RR, GG, and BB are s-polarized light that is a polarization component perpendicular to the reflection surface / transmission surface (incident surface) of the dichroic mirrors 23R, 23G, and 23B and the incident surface of the prism 3, respectively. That is, each of the laser light sources 21R, 21G, and 21B is polarized light whose vibration direction (polarization direction) is the Z′-axis direction, and the laser light RR in which the vibration direction matches the major axis direction of the ellipse having a cross-sectional shape. , GG, and BB are emitted. By making the laser beams RR, GG, BB s-polarized light, the loss of the laser beams RR, GG, BB at the dichroic mirrors 23R, 23G, 23B and the prism 3 can be reduced.

<Photosynthesis unit>
The dichroic mirror 23R has a characteristic of reflecting the laser light RR. The dichroic mirror 23B has a characteristic of reflecting the laser beam BB and transmitting the laser beam RR. The dichroic mirror 23G has characteristics of transmitting the laser light GG and reflecting the laser lights RR and BB. These dichroic mirrors 23R, 23G, and 23B match or substantially match (synthesize) the optical axes of the laser beams RR, GG, and BB of the respective colors, and one drawing laser beam LL is emitted in the + X′-axis direction. That is, the dichroic mirrors 23R, 23G, and 23B constitute a light combining unit 23 that combines the laser beams RR, GG, and BB.

  In the present embodiment, following the arrangement of the laser light sources 21R, 21G, and 21B, the dichroic mirror 23R, the dichroic mirror 23B, and the dichroic mirror 23G are arranged side by side in the −Y′-axis direction. The dichroic mirror 23R is provided so as to reflect the laser light RR emitted in the + X′-axis direction from the laser light source 21R in the −Y′-axis direction. The dichroic mirror 23B reflects the laser light BB emitted from the laser light source 21B in the + X′-axis direction in the −Y′-axis direction and transmits the laser light RR reflected in the −Y′-axis direction by the dichroic mirror 23R. To be provided. Further, the dichroic mirror 23G transmits the laser light GG emitted in the + X′-axis direction from the laser light source 21G and reflects the laser beams RR and BB reflected in the −Y′-axis direction by the dichroic mirrors 23R and 23B to the + X′-axis. It is provided to reflect in the direction. Thereby, the drawing laser beam LL formed by combining the laser beams RR, GG, and BB is emitted from the light combining unit 23 in the + X′-axis direction.

Here, the dichroic mirrors 23R, 23G, and 23B are arranged so that the incident angle to the prism 3 becomes larger as the laser light has a shorter wavelength in consideration of the dispersibility caused by the refractive index difference depending on the wavelength of the laser light. Is preferred. That is, the dichroic mirror 23R satisfies the relationship of (incident angle θ _B of blue laser light BB)> (incident angle θ _G of green laser light GG)> (incident angle θ _R of red laser light RR). , 23G, and 23B are arranged with the reflecting surface slightly shifted around the Z ′ axis.

(prism)
The prism 3 has a first function for inclining the optical axis of the drawing laser beam LL formed by combining the laser beams RR, GG, and BB, and a second function for deforming the shape (cross-sectional shape) of the drawing laser beam LL. And a third function that controls (condenses, etc.) the radiation angle of the drawing laser beam LL. The prism 3 is a substantially colorless and transparent polyhedron made of glass or quartz. Such a prism 3 is not particularly limited as long as it has the above function, and for example, a triangular prism having a substantially triangular prism shape can be used. For example, each corner of the triangular prism may be chamfered as long as it does not affect the function.

  First, the first function will be described. The prism 3 emits the drawing laser beam LL incident from the incident surface 31 in a direction inclined in the + Y′-axis direction with respect to the + X′-axis direction (a direction toward the center side of the housing 9) from the emission surface 32. . That is, the optical axis of the drawing laser beam LL is inclined around the Z ′ axis (in the X′Y ′ plane). According to such a prism 3, the drawing laser beam LL can be directed toward the center of the housing 9. In the housing 9, there is a sufficient space for arranging members on the extended line in the direction in which the laser light sources RR and BB are emitted from the laser light sources 21 </ b> R and 21 </ b> B, and the optical scanning unit 4 is disposed in this space. The internal space of the housing 9 can be used efficiently. That is, by tilting the optical axis of the drawing laser beam LL toward the center side of the housing 9, the dead space in the housing 9 (a useless space where no member is arranged) can be reduced, and image display can be performed. The unit 10 can be downsized.

  Next, the second function will be described. The prism 3 shapes the cross-sectional shape perpendicular to the optical axis of the drawing laser beam LL from a substantially elliptical shape to a substantially circular shape. Specifically, the prism 3 is used for drawing by increasing the width in the X′Y ′ in-plane direction while keeping the width in the Z′-axis direction of the cross-sectional shape of the incident drawing laser beam LL substantially constant. The cross-sectional shape of the laser beam LL is shaped into a substantially circular shape. In other words, the prism 3 increases the length of the minor axis of the ellipse, which is a sectional shape, and shapes the sectional shape of the drawing laser beam LL so that the ratio of the minor axis to the major axis (aspect ratio) is approximately 1. To do. Thus, by making the cross-sectional shape of the drawing laser beam LL substantially circular, the image display unit 10 can exhibit excellent image display characteristics. Here, as described above, it is only necessary to rotate the prism 3 in the X′Y ′ plane by making the cross-sectional shape of the drawing laser beam LL substantially elliptical with the Z′-axis direction as the major axis. For this reason, it can arrange | position so that the length of the thickness direction (Z'-axis direction) of the housing | casing 9 which the prism 3 follows may become the minimum. Therefore, the image display unit 10 can be downsized (thinned).

Next, the third function will be described. The emission surface 32 of the prism 3 is formed of a curved convex surface (lens surface), functions as a condensing lens, and condenses (converges) the drawing laser light LL incident on the prism 3 as parallel light. By converging the drawing laser beam LL in this way, a clearer image (high-resolution image) can be displayed. Further, by causing the emission surface 32 to function as a condensing lens, it is not necessary to provide a condensing lens separately from the prism 3, the number of parts can be reduced, and the image display unit 10 can be downsized. Note that the configuration of the emission surface 32 of the prism 3 is not limited to the convex surface (condensing lens) as long as the radiation angle can be controlled, and may be, for example, a concave surface (diverging lens).
In the image display unit 10, the prism 3 is used as an optical member. However, any optical member other than the prism may be used as long as the same effect as the function of the prism 3 described above can be exhibited.

  The drawing light source unit 2 and the prism 3 have been described in detail above. In the image display unit 10, as shown in FIG. 6, the optical paths until the laser beams RR, GG, and BB enter the optical scanning unit 4 are positioned on a plane F (X′Y ′ plane) that is the same virtual plane. doing. That is, in the plane F, the laser light sources 21R, 21G, and 21B emit laser beams RR, GG, and BB, and the light combining unit 23 combines the laser beams RR, GG, and BB to emit drawing laser light LL. The prism 3 inclines the optical axis of the drawing laser beam LL within the X′Y ′ plane.

(Optical scanning part)
The optical scanning unit 4 has a function of two-dimensionally scanning the drawing laser light LL that has passed through the prism 3. The optical scanning unit 4 is not particularly limited as long as the drawing laser beam LL can be two-dimensionally scanned. For example, an optical scanner 40 having the following configuration can be used.
As shown in FIGS. 7 and 8, the optical scanner 40 includes a movable portion 41, a pair of shaft portions 421 and 422 (first shaft portion), a frame body portion 43, two pairs of shaft portions 441, 442, 443, 444 (second shaft portion), a support portion 45, a permanent magnet 46, a coil 47, a magnetic core 48, and a voltage application portion 49 are provided.

  Here, the movable portion 41 and the pair of shaft portions 421 and 422 constitute a first vibration system that swings (reciprocates) around the first axis J1. The movable portion 41, the pair of shaft portions 421, 422, the frame body portion 43, the two pairs of shaft portions 441, 442, 443, 444 and the permanent magnet 46 swing around the second axis J2 (reciprocating rotation). A second vibration system that moves). Moreover, the permanent magnet 46, the coil 47, and the voltage application part 49 comprise the drive part which drives the 1st vibration system mentioned above and the 2nd vibration system.

Hereinafter, each part of the optical scanner 40 will be described in detail sequentially.
As shown in FIGS. 7 and 8, the movable portion 41 includes a base 411 and a light reflecting plate 413 fixed to the base 411 via a spacer 412. A light reflecting portion 414 having light reflectivity is provided on the upper surface (one surface) of the light reflecting plate 413. And the surface of the light reflection part 414 comprises the light reflection surface 414a which reflects the drawing laser beam LL. As described above, the movable portion 41 swings around the first axis J1 and the second axis J2. That is, it can be said that the base 411, the spacer 412, the light reflecting plate 413, and the light reflecting surface 414a constituting the movable portion 41 also swing around the first axis J1 and the second axis J2.

The light reflecting plate 413 is separated from the base 411 and the shaft portions 421 and 422 in the thickness direction, and overlaps the shaft portions 421 and 422 when viewed from the thickness direction (hereinafter also referred to as “plan view”). Is provided.
Therefore, the area of the plate surface of the light reflecting plate 413 can be increased while shortening the distance between the shaft portion 421 and the shaft portion 422. In addition, since the distance between the shaft portion 421 and the shaft portion 422 can be shortened, the size of the frame body portion 43 can be reduced. Furthermore, since the size of the frame body portion 43 can be reduced, the distance between the shaft portions 441 and 442 and the shaft portions 443 and 444 can be shortened. For this reason, by connecting the base 411 and the light reflecting plate 413 with the spacer 412, the optical scanner 40 can be downsized even if the area of the plate surface of the light reflecting plate 413 is increased. That is, the dimension in the direction along the plane including the first axis J1 and the second axis J2 of the optical scanning unit 4 can be reduced. Then, by arranging the optical scanner 40 (optical scanning unit 4) so that the light reflecting surface 414a is perpendicular to the surface F, the direction perpendicular to the surface F of the image display device 1 (Z′-axis direction). ) Can be reduced.

  The light reflecting plate 413 is formed so as to cover the entire shaft portions 421 and 422 in plan view. In other words, each of the shaft portions 421 and 422 is located inside the outer periphery of the light reflecting plate 413 in plan view. Thereby, the area of the plate | board surface of the light reflection board 413 becomes large, As a result, the area of the light reflection part 414 can be enlarged. Further, unnecessary light (for example, light that could not be incident on the light reflection plate 413) can be prevented from being reflected by the shaft portions 421 and 422 and becoming stray light.

The light reflecting plate 413 is formed so as to cover the entire frame body portion 43 in plan view. In other words, the frame body part 43 is located on the inner side with respect to the outer periphery of the light reflecting plate 413 in plan view. Thereby, the area of the plate | board surface of the light reflection board 413 becomes large, As a result, the area of the light reflection part 414 can be enlarged. Further, it is possible to prevent unnecessary light from being reflected by the frame body portion 43 and becoming stray light.
Furthermore, the light reflecting plate 413 is formed so as to cover the entire shaft portions 441, 442, 443, and 444 in plan view. Thereby, the area of the plate | board surface of the light reflection board 413 becomes large, As a result, the area of the light reflection part 414 can be enlarged. Further, it is possible to prevent unnecessary light from being reflected by the shaft portions 441, 442, 443, and 444 and becoming stray light.

In the present embodiment, the light reflecting plate 413 has a circular shape in plan view. In addition, the planar view shape of the light reflection plate 413 is not limited to this, and may be a polygon such as an ellipse or a quadrangle.
A hard layer 415 is provided on the lower surface of the light reflecting plate 413 (the other surface, the surface on the base 411 side of the light reflecting plate 413).

  The hard layer 415 is made of a material harder than the constituent material of the light reflecting plate 413 main body. Thereby, the rigidity of the light reflecting plate 413 can be increased. Therefore, it is possible to prevent or suppress the bending when the light reflecting plate 413 is swung. Further, the thickness of the light reflecting plate 413 can be reduced, and the moment of inertia when the light reflecting plate 413 swings around the first axis J1 and the second axis J2 can be suppressed.

  The constituent material of the hard layer 415 is not particularly limited as long as it is a material harder than the constituent material of the light reflecting plate 413 body. For example, diamond, crystal, sapphire, lithium tantalate, potassium niobate, A carbon nitride film or the like can be used, but it is particularly preferable to use diamond. The hard layer 415 is provided as necessary, and can be omitted.

Further, the lower surface of the light reflecting plate 413 is fixed to the base portion 411 via a spacer 412. Accordingly, the light reflecting plate 413 can be swung around the first axis J1 while preventing contact with the shaft portions 421 and 422, the frame body portion 43, and the shaft portions 441, 442, 443, and 444.
The base 411 is located on the inner side with respect to the outer periphery of the light reflecting plate 413 in plan view. The area of the base 411 in plan view is preferably as small as possible as long as the base 411 can support the light reflection plate 413 via the spacer 412. Thereby, the distance between the shaft part 421 and the shaft part 422 can be reduced while increasing the area of the plate surface of the light reflecting plate 413.

  The frame part 43 has a frame shape and is provided so as to surround the base part 411 of the movable part 41 described above. In other words, the base 411 of the movable portion 41 is provided inside the frame body portion 43 having a frame shape. The frame body portion 43 is supported by the support portion 45 via shaft portions 441, 442, 443, and 444. Further, the base portion 411 of the movable portion 41 is supported by the frame body portion 43 via the shaft portions 421 and 422.

  Further, the length of the frame body portion 43 in the direction along the first axis J1 is longer than the length in the direction along the second axis J2. That is, when the length of the frame body portion 43 in the direction along the first axis J1 is a and the length of the frame body portion 43 in the direction along the second axis J2 is b, a> b. Satisfy the relationship. Accordingly, it is possible to suppress the length of the optical scanner 40 in the direction along the second axis J2 while securing the length necessary for the shaft portions 421 and 422. As will be described later, since the optical scanner 40 is disposed in the housing 9 so that the second axis J2 is parallel to the Z ′ axis, the optical scanner 40 satisfies the above-described relationship of a> b, so The thickness (length in the Z′-axis direction) of the body 9 can be reduced.

  In addition, the frame body portion 43 has a shape along the outer shape of the structure including the base portion 411 of the movable portion 41 and the pair of shaft portions 421 and 422 in plan view. As a result, the frame body portion allows the vibration of the first vibration system configured by the movable portion 41 and the pair of shaft portions 421, 422, that is, the swing of the movable portion 41 around the first axis J1. 43 can be reduced in size. The shape of the frame body portion 43 is not limited to the illustrated shape as long as it is a frame shape.

  The shaft portions 421 and 422 and the shaft portions 441, 442, 443, and 444 can be elastically deformed, respectively. The shaft portions 421 and 422 connect the movable portion 41 and the frame body portion 43 so that the movable portion 41 can swing around the first axis J1. Further, the shaft portions 441, 442, 443, and 444 make the frame body portion 43 and the support portion 45 so that the frame body portion 43 can swing around the second axis J2 orthogonal to the first axis J1. It is connected.

  The shaft portions 421 and 422 are arranged so as to face each other via the base portion 411 of the movable portion 41. In addition, each of the shaft portions 421 and 422 has a longitudinal shape extending in a direction along the first axis J1. Each of the shaft portions 421 and 422 has one end connected to the base 411 and the other end connected to the frame body 43. In addition, the shaft portions 421 and 422 are arranged so that the central axis coincides with the first axis J1. Each of the shaft portions 421 and 422 is torsionally deformed as the movable portion 41 swings around the first axis J1.

  The shaft portions 441 and 442 and the shaft portions 443 and 444 are arranged so as to face each other with the frame body portion 43 interposed therebetween. In addition, the shaft portions 441, 442, 443, and 444 each have a longitudinal shape extending in the direction along the second axis J2. Each of the shaft portions 441, 442, 443, 444 has one end connected to the frame body portion 43 and the other end connected to the support portion 45. The shaft portions 441 and 442 are disposed so as to face each other via the second axis J2. Similarly, the shaft portions 443 and 444 are disposed so as to face each other via the second axis J2. ing. Such shaft portions 441, 442, 443, and 444 are twisted and deformed as a whole by the swing of the frame body portion 43 around the second axis J2, respectively. .

As described above, the movable portion 41 can be swung around the first axis J1, and the frame body portion 43 can be swung around the second axis J2. ) Can be swung around two axes of a first axis J1 and a second axis J2 orthogonal to each other.
Note that the shapes of the shaft portions 421 and 422 and the shaft portions 441, 442, 443, and 444 are not limited to those described above. You may do it.

The base portion 411, the shaft portions 421, 422, the frame body portion 43, the shaft portions 441, 442, 443, 444 and the support portion 45 as described above are integrally formed.
In this embodiment, the base part 411, the shaft parts 421, 422, the frame part 43, the shaft parts 441, 442, 443, 444 and the support part 45 are composed of the first Si layer (device layer) and the SiO ₂ layer (box Layer) and a second Si layer (handle layer) are formed by etching the SOI substrate. Thereby, the vibration characteristics of the first vibration system and the second vibration system can be made excellent. Further, since the SOI substrate can be finely processed by etching, the base portion 411, the shaft portions 421 and 422, the frame portion 43, the shaft portions 441, 442, 443, and 444 and the support portion 45 are formed using the SOI substrate. By forming, the dimensional accuracy can be improved, and the optical scanner 40 can be downsized.

  The base portion 411, the shaft portions 421 and 422, and the shaft portions 441, 442, 443, and 444 are each composed of the first Si layer of the SOI substrate. Thereby, the elasticity of the shaft portions 421 and 422 and the shaft portions 441, 442, 443, and 444 can be made excellent. Further, it is possible to prevent the base portion 411 from coming into contact with the frame body portion 43 when rotating around the first axis J1.

Further, frame 43 and the support portion 45, respectively, a first Si layer of the SOI substrate, and a stack of the SiO ₂ layer and the second Si layer. Thereby, the rigidity of the frame part 43 and the support part 45 can be made excellent. In addition, the SiO ₂ layer and the second Si layer of the frame part 43 have not only a function as a rib that increases the rigidity of the frame part 43 but also a function of preventing the movable part 41 from contacting the permanent magnet 46. Have.

Further, in plan view, the portions of the upper surfaces of the shaft portions 421 and 422, the shaft portions 441, 442, 443, and 444, the frame body portion 43, and the support portion 45 that are located outside the light reflecting plate 413 are prevented from being reflected It is preferable that the treatment is performed. Thereby, it is possible to prevent unnecessary light irradiated to other than the light reflection plate 413 from becoming stray light. Such an antireflection treatment is not particularly limited, and examples thereof include formation of an antireflection film (dielectric multilayer film), roughening treatment, and black treatment.
Note that the above-described constituent materials and forming methods of the base portion 411, the shaft portions 421 and 422, and the shaft portions 441, 442, 443, and 444 are examples, and the present invention is not limited thereto.

In the present embodiment, the spacer 412 and the light reflecting plate 413 are also formed by etching the SOI substrate. The spacer 412 is composed of a laminate composed of the SiO ₂ layer and the second Si layer of the SOI substrate. Further, the light reflecting plate 413 is composed of a first Si layer of an SOI substrate. In this manner, by forming the spacer 412 and the light reflecting plate 413 using the SOI substrate, the spacer 412 and the light reflecting plate 413 joined to each other can be manufactured easily and with high accuracy.
Such a spacer 412 is bonded to the base 411 by a bonding material (not shown) such as an adhesive or a brazing material.

A permanent magnet 46 is joined to the lower surface of the frame body portion 43 described above. The joining method of the permanent magnet 46 and the frame body portion 43 is not particularly limited, but for example, a joining method using an adhesive can be used. The permanent magnet 46 is magnetized in a direction inclined with respect to the first axis J1 and the second axis J2 in plan view.
In the present embodiment, the permanent magnet 46 has a longitudinal shape (bar shape) extending in a direction inclined with respect to both the first axis J1 and the second axis J2. The permanent magnet 46 is magnetized in the longitudinal direction. That is, the permanent magnet 46 is magnetized so that one end is an S pole and the other end is an N pole. Further, the permanent magnet 46 is provided so as to be symmetric with respect to the intersection of the first axis J1 and the second axis J2 in plan view.

The inclination angle θ in the magnetization direction (extending direction) of the permanent magnet 46 with respect to the second axis J2 is not particularly limited, but is preferably 30 ° or more and 60 ° or less, and is 45 ° or more and 60 ° or less. Is more preferable, and it is still more preferable that it is 45 degrees. By providing the permanent magnet 46 in this manner, the movable portion 41 can be swung around the second axis J2 smoothly and reliably.
As such a permanent magnet 46, for example, a neodymium magnet, a ferrite magnet, a samarium cobalt magnet, an alnico magnet, a bond magnet, or the like can be suitably used. Such a permanent magnet 46 is obtained by magnetizing a hard magnetic material, and is formed, for example, by magnetizing a hard magnetic material before magnetization in the frame portion 43. This is because if the permanent magnet 46 that has already been magnetized is to be installed in the frame body portion 43, the permanent magnet 46 may not be installed at a desired position due to the influence of the magnetic field of the outside or other components.

A coil 47 is provided immediately below the permanent magnet 46. Thereby, the magnetic field generated from the coil 47 can be efficiently applied to the permanent magnet 46. Thereby, power saving and size reduction of the optical scanner 40 can be achieved. The coil 47 is provided by being wound around a magnetic core 48. Thereby, the magnetic field generated by the coil 47 can be efficiently applied to the permanent magnet 46. The magnetic core 48 may be omitted.
Such a coil 47 is electrically connected to the voltage application unit 49. Then, when a voltage is applied to the coil 47 by the voltage application unit 49, a magnetic field having a magnetic flux orthogonal to the first axis J1 and the second axis J2 is generated from the coil 47.

  As shown in FIG. 9, the voltage application unit 49 includes a first voltage generation unit 491 that generates a first voltage V1 for rotating the movable unit 41 around the first axis J1, and a movable unit 41. A second voltage generator 492 for generating a second voltage V2 for rotating around the second axis J2, and a voltage superimposing unit 493 for superimposing the first voltage V1 and the second voltage V2. The voltage superimposed by the voltage superimposing unit 493 is applied to the coil 47.

  As shown in FIG. 10A, the first voltage generator 491 generates a first voltage V1 (main scanning voltage) that periodically changes at a period T1. The first voltage V1 has a waveform like a sine wave. The frequency (1 / T1) of the first voltage V1 is preferably 10 to 40 kHz, for example. In the present embodiment, the frequency of the first voltage V1 is set to be equal to the torsional resonance frequency (f1) of the first vibration system including the movable portion 41 and the pair of shaft portions 421 and 422. Yes. Thereby, the rotation angle of the movable portion 41 around the first axis J1 can be increased.

On the other hand, as shown in FIG. 10B, the second voltage generator 492 generates a second voltage V2 (sub-scanning voltage) that periodically changes at a period T2 different from the period T1. . The second voltage V2 has a sawtooth waveform. The frequency (1 / T2) of the second voltage V2 may be different from the frequency (1 / T1) of the first voltage V1, and is preferably 30 to 80 Hz (about 60 Hz), for example. In the present embodiment, the frequency of the second voltage V <b> 2 includes the movable portion 41, the pair of shaft portions 421 and 422, the frame body portion 43, the two pairs of shaft portions 441, 442, 443 and 444 and the permanent magnet 46. The frequency is adjusted to be different from the torsional resonance frequency (resonance frequency) of the second vibration system.
The frequency of the second voltage V2 is preferably smaller than the frequency of the first voltage V1. As a result, the movable portion 41 is swung around the first axis J1 at the frequency of the first voltage V1, while swinging around the second axis J2 at the frequency of the second voltage V2, more reliably and smoothly. Can be moved.

Further, when the torsional resonance frequency of the first vibration system is f1 [Hz] and the torsional resonance frequency of the second vibration system is f2 [Hz], f1 and f2 satisfy the relationship of f2 <f1. Is preferable, and it is more preferable to satisfy the relationship of 10f2 ≦ f1. As a result, the movable part 41 is rotated more smoothly around the first axis J1 at the frequency of the first voltage V1 and at the frequency of the second voltage V2 around the second axis J2. be able to. On the other hand, if f1 ≦ f2, the vibration of the first vibration system may occur due to the frequency of the second voltage V2.
The first voltage generation unit 491 and the second voltage generation unit 492 are connected to the control unit 6 and are driven based on signals from the control unit 6. A voltage superimposing unit 493 is connected to the first voltage generating unit 491 and the second voltage generating unit 492.
The voltage superimposing unit 493 includes an adder 493 a for applying a voltage to the coil 47. The adder 493a receives the first voltage V1 from the first voltage generator 491 and receives the second voltage V2 from the second voltage generator 492, and superimposes these voltages and applies them to the coil 47. It has become.

  Next, a method for driving the optical scanner 40 will be described. The frequency of the first voltage V1 is set equal to the torsional resonance frequency of the first vibration system, and the frequency of the second voltage V2 is different from the torsional resonance frequency of the second vibration system. In addition, the frequency is set to be lower than the frequency of the first voltage V1 (for example, the frequency of the first voltage V1 is set to 18 kHz and the frequency of the second voltage V2 is set to 60 Hz). .

For example, the first voltage V 1 as shown in FIG. 10A and the second voltage V 2 as shown in FIG. 10B are superimposed by the voltage superimposing unit 493, and the superimposed voltage is applied to the coil 47. Apply.
Then, the first voltage V <b> 1 tries to attract one end (N pole) of the permanent magnet 46 to the coil 47 and the other end (S pole) of the permanent magnet 46 from the coil 47. (This magnetic field is referred to as “magnetic field A1”) and one end (N pole) of the permanent magnet 46 is to be separated from the coil 47, and the other end (S pole) of the permanent magnet 46 is attracted to the coil 47. (The magnetic field is referred to as “magnetic field A2”) alternately.

  As the magnetic field A1 and the magnetic field A2 are alternately switched in this way, vibration having a torsional vibration component around the first axis J1 is excited in the frame portion 43, and the shaft portions 421 and 422 are accompanied by the vibration. The torsional deformation of the movable part 41 swings around the first axis J1 at the frequency of the first voltage V1. Since the frequency of the first voltage V1 is equal to the torsional resonance frequency of the first vibration system, the movable portion 41 can be largely swung by resonance vibration.

  On the other hand, the second voltage V <b> 2 is used to attract one end (N pole) of the permanent magnet 46 to the coil 47 and to magnetically separate the other end (S pole) of the permanent magnet 46 from the coil 47. (This magnetic field is referred to as “magnetic field B1”) and one end (N pole) of the permanent magnet 46 is to be separated from the coil 47, and the other end (S pole) of the permanent magnet 46 is attracted to the coil 47. (The magnetic field is referred to as “magnetic field B2”) alternately.

  As the magnetic field B1 and the magnetic field B2 are alternately switched in this way, the frame portion 43 together with the movable portion 41 and the second voltage V2 while twisting and deforming the shaft portions 441 and 442 and the shaft portions 443 and 444, respectively. Oscillates around the second axis J2. As described above, the frequency of the second voltage V2 is set to be extremely lower than the frequency of the first voltage V1, and the torsional resonance frequency of the second vibration system is higher than the torsional resonance frequency of the first vibration system. Therefore, the movable portion 41 can be prevented from rotating around the first axis J1 at the frequency of the second voltage V2.

  As described above, in the optical scanner 40, by applying a voltage obtained by superimposing the first voltage V1 and the second voltage V2 to the coil 47, the movable portion 41 is moved around the first axis J1. It is possible to rotate around the second axis J2 at the frequency of the second voltage V2 while rotating at the frequency of the voltage V1. As a result, the cost and size of the apparatus are reduced, and the movable portion 41 is swung around each of the first axis J1 and the second axis J2 by an electromagnetic drive method (moving magnet method). The drawing laser beam LL reflected by the light reflecting portion 414 can be two-dimensionally scanned. In addition, since the number of parts (permanent magnets and coils) constituting the drive source can be reduced, a simple and small configuration can be achieved. Further, since the coil 47 is separated from the vibration system of the optical scanner 40, it is possible to prevent an adverse effect of the heat generated by the coil 47 on the vibration system.

  The configuration of the optical scanner 40 has been described in detail above. According to the two-dimensional scanning optical scanner 40 having the gimbal type as described above, since the drawing laser beam LL can be two-dimensionally scanned by one apparatus, for example, a one-dimensional scanning optical scanner is used. Compared with the configuration in which the drawing laser beam LL is two-dimensionally scanned in combination, the optical scanning unit 4 can be reduced in size and alignment can be easily adjusted. In particular, each of the first axis J1 and the second axis J2 of the light reflecting plate 413 is reduced while reducing the dimension in the direction along the plane including the first axis J1 and the second axis J2 of the optical scanning unit 4. The swing angle around the axis can be increased.

  The optical scanner 40 is an electromagnetically driven optical scanner that is driven using a permanent magnet 46 and a coil 47. By adopting such a configuration, as shown in FIG. 8, the permanent magnet 46 and the coil 47 must be arranged to face each other, so the thickness of the optical scanner 40 (the first axis J1 and the second axis J2). The length in the direction of the axis J3 intersecting with the intersection of the two axes is thicker), but on the contrary, the size (width) in the in-plane direction including the first axis J1 and the second axis J2 is decreased. can do. As described above, the optical scanner 40 is an optical scanner suitable for the image display unit 10 by reducing the size in the in-plane direction rather than the thickness direction.

  As shown in FIGS. 4 and 6, in the optical scanner 40 having the configuration described above, the light reflecting portion 414 has an X′Y ′ plane in a non-driven state (a state where no voltage is applied to the coil 47). It is arrange | positioned in the housing | casing 9 so that it may become perpendicular | vertical to. In other words, in the non-driven state, the optical scanner 40 has a housing so that the plane including the first axis J1 and the second axis J2 is orthogonal to the X′Y ′ plane (the axis J3 is located in the plane F). It is arranged in the body 9. Here, as described above, since the size of the optical scanner 40 in the in-plane direction of the plane including the first axis J1 and the second axis J2 is kept small, by adopting such an arrangement. Thus, the image display unit 10 (housing 9) can be downsized (thinned). Although the optical scanner 40 is not so thin in the direction of the axis J3, the image display unit 10 is arranged so that the axis J3 is located in the plane F, and accordingly the size of the apparatus is minimally increased. It is limited to the limit.

The drawing laser light LL that has passed through the prism 3 enters the light reflecting portion 414 from a direction inclined with respect to the axis J3. While the optical scanner 40 is not driven, the angle formed by the axis J3 and the drawing laser beam LL incident on the light reflecting portion 414 is not particularly limited, but is preferably about 30 ° or more and 60 ° or less.
In this manner, the drawing laser beam LL scanned by the optical scanner 40 is incident on the light reflecting unit 414 from the direction inclined with respect to the axis J3 (the normal line of the light reflecting surface 414a). Can be emitted to the outside of the housing 9 without interfering with other members (for example, the prism 3). Therefore, it is not necessary to install a plane mirror, a prism, or the like that changes the optical path of the drawing laser beam LL scanned by the optical scanner 40, so that the image display unit 10 can be downsized.

In the optical scanner 40, the first axis J1 (shaft portions 421, 422) is parallel to the in-plane direction of the X′Y ′ plane (matches the surface F), and the second axis J2 (shaft portions 441, 442, 443, 444) are arranged in parallel with the Z ′ axis. Here, in the optical scanner 40, the amplitude (oscillation angle) of the movable portion 41 around the first axis J1 that is resonant drive is larger than the amplitude of the movable portion 41 around the second axis J2 that is non-resonant drive. large. As described above, the optical scanner 40 is arranged such that the amplitude of the movable portion 41 having the amplitude in the Z′-axis direction is larger than the amplitude of the movable portion 41 in the in-plane direction of the X′Y ′ plane. . By adopting such an arrangement, the following effects can be exhibited.
As described above, since the drawing laser beam LL is incident on the light reflecting unit 414 from a direction inclined with respect to the axis J3, the scanning light composed of the drawing laser beam LL two-dimensionally scanned by the light reflecting unit 414 is obtained. The shape of the drawable area S that can be drawn on the virtual screen along the cross section is not an accurate rectangle but is distorted.

As in the present embodiment, the optical scanner 40 in which the amplitude (swing angle) of the movable part 41 around the first axis J1 is larger than the amplitude of the movable part 41 around the second axis J2 is used as the first axis J1. 11 is parallel to the in-plane direction of the X′Y ′ plane and the second axis J2 is parallel to the Z ′ axis, the shape of the drawable region S is as shown in FIG. In addition, distortion is reduced.
On the other hand, the optical scanner 40 in which the amplitude (swing angle) of the movable part 41 around the first axis J1 is larger than the amplitude of the movable part 41 around the second axis J2, and the second axis J2 is X ′. When arranged so that it is parallel to the in-plane direction of the Y ′ plane and the first axis J1 is parallel to the Z ′ axis, the shape of the drawable region S is distorted as shown in FIG. Becomes larger.

  For this reason, the drawable area S shown in FIG. 11A is more effective than the drawable area S shown in FIG. It is possible to increase the area of the region (S ′) where the image is displayed by irradiating the drawing laser beam LL. Accordingly, since the drawable area S shown in FIG. 11A has a larger area that can be effectively used for drawing than the drawable area S shown in FIG. 11B, a more efficient and larger image can be drawn. Can do.

  The arrangement of the optical scanner 40 is preferably such that the first axis J1 is parallel to the in-plane direction of the X′Y ′ plane and the second axis J2 is parallel to the Z ′ axis. The arrangement may be such that the second axis J2 is parallel to the in-plane direction of the X′Y ′ plane and the first axis J1 is parallel to the Z ′ axis. In this case, if the amplitude (swing angle) of the movable part 41 around the second axis J2 is larger than the amplitude of the movable part 41 around the first axis J1, the drawable area as shown in FIG. S can be realized.

(Detection unit)
The detection unit 5 shown in FIG. 4 has a function of detecting the intensity of the drawing laser beam LL (respective laser beams RR, GG, and BB). Such a detection unit 5 includes a light receiving element 51 such as a photodiode provided in the housing 9. The incident surface 31 of the prism 3 described above is configured to slightly reflect each laser beam RR, GG, BB (for example, a reflectance of about 0.1%), and a light receiving element on the optical path of the reflected light 51 is located. The light receiving element 51 outputs a signal (voltage) having a magnitude corresponding to the intensity of the received reflected light, and based on this signal, the intensity of each laser beam RR, GG, BB can be detected.

Information regarding the intensity of each detected laser beam RR, BB, GG is sent to the control unit 6, and the control unit 6 controls driving of the laser light sources 21R, 21G, 21B based on the received information.
Specifically, the reflectance and transmittance of the laser beams RR, GG, and BB of the collimator lenses 22R, 22G, and 22B and the dichroic mirrors 23R, 23G, and 23B and the laser beams RR and GG of the incident surface 31 in advance. , The reflectance of BB is measured, and these pieces of information are stored in a memory (not shown) of the control unit 6.

  Next, for example, before starting drawing an image, a drive signal of a predetermined magnitude (voltage) is transmitted from the control unit 6 to the drive circuit, and the laser light RR is emitted from the laser light source 21R. A part of the laser light RR is reflected by the incident surface 31 of the prism 3, and the light receiving element 51 receives this reflected light, and the intensity of the reflected light is detected. Then, the actual intensity of the laser light RR emitted from the laser light source 21R is obtained based on the reflectance of the laser light RR of each part stored in the memory. Thereby, the relationship between the intensity of the laser beam RR and the magnitude (voltage value) of the drive signal is obtained, and the magnitude of the drive signal necessary for emitting the laser beam RR having a predetermined intensity becomes clear.

Such a relationship is stored in the memory. And when drawing an image, based on this relationship, the control part 6 transmits a desired drive signal to a drive circuit so that laser light RR of desired intensity is emitted from the laser light source 21R. Similarly, for the laser beams GG and BB, the relationship between the intensity of the laser beams GG and BB and the magnitude of the drive signal is obtained. Based on the obtained relationship, the laser beams GG and BB having the desired intensity are obtained from the laser light sources 21G and 21B. The control unit 6 transmits a desired drive signal to the drive circuit so that is emitted.
Thereby, the drawing laser beam LL having a desired color and luminance can be generated, and the image display characteristics are improved.

  In the above description, the case where the relationship between the intensity of the laser beam RR and the magnitude (voltage value) of the drive signal is obtained before the drawing of the image has been described. For example, the image may be in the middle of drawing. As described above, the drawing laser beam LL is applied to the effective drawing area S ′ in the drawable area S and is not applied to other parts (non-drawing area S ″). Therefore, an image is drawn. When the movable portion 41 (light reflecting portion 414) is directed to the non-drawing region S ″ and the drawing laser beam LL is not emitted, the intensity of the laser beam RR and the drive signal are as described above. You may obtain the relationship with the magnitude | size (voltage value) of.

(Control part)
The control unit 6 shown in FIG. 4 has a function of controlling the operations of the drawing light source unit 2 and the light scanning unit 4. Specifically, the control unit 6 drives the optical scanner 40 to swing the movable unit 41 around the first axis J1 and the second axis J2, and in synchronization with the swing of the movable unit 41. The drawing laser beam LL is emitted from the drawing light source unit 2. For example, based on image data transmitted from an external computer, the control unit 6 emits laser beams RR, GG, and BB having a predetermined intensity from the laser light sources 21R, 21G, and 21B at a predetermined timing, and outputs a predetermined color and intensity ( (Luminance) drawing laser beam LL is emitted at a predetermined timing. Thereby, an image according to the image data can be displayed.

(Casing)
The housing 9 is supported by the frame 7 as shown in FIG. 3, and houses the light source unit 2 for drawing, the prism 3, the light scanning unit 4, the detection unit 5 and the control unit 6 as shown in FIG. doing. Thereby, the laser light sources 21R, 21G, and 21B, the light combining unit 23, the optical scanning unit 4, and the like can be protected. Further, the positional relationship among the laser light sources 21R, 21G, and 21B, the light combining unit 23, the light scanning unit 4 and the like can be stably fixed by the housing 9 or a member fixedly provided on the case 9. Furthermore, the laser light sources 21R, 21G, and 21B, the light combining unit 23, the light scanning unit 4, and the like can be unitized together with the housing 9 so as to be detachable from the frame 7. In addition, the control part 6 may be accommodated in the housing | casing 9 like this embodiment, and the control part 6 may be provided in the outer side of the housing | casing 9. FIG.

  In the present embodiment, the housing 9 is supported by one temple portion 73 of the frame 7. That is, the laser light sources 21R, 21G, and 21B, the light combining unit 23, and the optical scanning unit 4 are mounted on the temple unit 73. Thereby, with a simple configuration, the scanning light emitted from the image display unit 10 can be reflected by the reflecting member 81 and guided to one eye EY. Therefore, the eyeglass-type image display device 1 can be reduced in size.

  The housing 9 can be rotated with respect to the frame 7. Specifically, as shown in FIGS. 2A and 3, the housing 9 includes a first member 92 provided on the housing 9 side, a second member 79 provided on the frame 7 side, The hinge is constituted by a pin 93 penetrating the first member 92 and the second member 79 and is rotatable with respect to the frame 7. Thereby, the position where the light (scanning light) scanned by the optical scanning unit 4 is projected can be adjusted.

  Such a hinge is, for example, a torque hinge, and can hold the rotation angle of the housing 9 with respect to the frame 7 (the aforementioned angle α) at an arbitrary position. In the present embodiment, the pin 93 penetrates the first member 92 and the second member 79 in the Z′-axis direction, and the housing 9 is rotated around the axis parallel to the Z′-axis with respect to the frame 7. It is possible. Therefore, the angle α described above can be arbitrarily changed.

  The rotation center axis of the housing 9 with respect to the frame 7 is determined according to the positional relationship between the reflecting member 81 and the housing 9, the degree of necessity of adjusting the projection position of the scanning light, etc. Z ′ It may be inclined with respect to the axis, and may be parallel or inclined with respect to the Y ′ axis or the Z ′ axis. Moreover, as a structure which enables the housing | casing 9 to rotate with respect to the flame | frame 7, it is not limited to the thing of illustration, For example, well-known various hinges can be used. Further, the reflection member 81 and the housing 9 may be integrally moved or rotated with respect to the frame 7 while maintaining the relative position and posture relationship between the reflection member 81 and the housing 9. .

The housing 9 has a flat shape along the surface F. That is, the housing 9 has an extension along the X′Y ′ plane and has a height in the Z ′ axis direction. In the housing 9, the drawing light source unit 2, the prism 3, the optical scanning unit 4, and the detection unit 5 are arranged and accommodated along the X′Y ′ plane. As a result, the laser light sources 21R, 21G, and 21B, the light combining unit 23, the light scanning unit 4, and the like can be housed in the casing 9 that has been reduced in thickness.
The housing 9 of the present embodiment has a substantially rectangular outer shape when viewed from the thickness direction. The housing 9 is provided with a window 91 made of, for example, a transparent member (glass, plastic, etc.), and a drawing laser scanned by the light scanning unit 4 through the window 91. Light LL (scanning light) is emitted outside the housing 9.

The configuration of the image display unit 10 has been described in detail above.
In such an image display unit 10, each member, that is, the laser light sources 21R, 21G, and 21B, the collimator lenses 22R, 22G, and 22B, the dichroic mirrors 23R, 23G, and 23B, the prism 3, the optical scanner 40, and the light receiving element 51 are provided. , Are arranged in a plane (in the same virtual plane) in the X′Y ′ plane direction. The optical axes of the laser beams RR, GG, BB emitted from the laser light sources 21R, 21G, 21B, and the drawing laser beam LL, which is a combination thereof, are X′Y until they enter the optical scanner 40, respectively. 'Located on the same virtual plane (plane F) parallel to the plane. That is, the optical paths until the laser beams RR, GG, and BB emitted from the laser light sources 21R, 21G, and 21B enter the optical scanning unit 4 are provided on the same plane F (virtual plane). Thereby, the structure (image display unit 10) including the laser light sources 21R, 21G, and 21B, the light combining unit 23, and the light scanning unit 4 can be thinned.

  Here, the light reflecting surface 414a is disposed so as to be orthogonal to the surface F. In addition, since the image display unit 10 tilts the optical axis of the drawing laser beam LL within the plane F by the prism 3, each component (particularly the optical scanner 40) can be arranged in a plane. Therefore, the alignment of each component of the image display unit 10 can be made planar, and the assemblability of the image display unit 10 can be made excellent. Furthermore, since the image display unit 10 shapes the drawing laser beam LL by the prism 3, it can exhibit excellent image display characteristics. Further, the number of parts can be reduced, and the size can be reduced accordingly.

  In particular, the surface F is along the vertical direction of the head H (that is, the Z-axis direction) when the frame 7 is attached to the head H. More specifically, the surface F is along the side surface or front surface of the head H in use. Thereby, as described above, the thinned image display unit 10 can be arranged along the direction perpendicular to the thickness direction of the frame 7. As a result, the entire image display device 1 can be reduced in size.

As described above, the image display device and the head mounted display of the present invention have been described based on the illustrated embodiment, but the present invention is not limited to this, and the configuration of each unit is an arbitrary configuration having the same function Can be substituted. In addition, any other component may be added to the present invention.
In the above-described embodiment, the configuration has been described in which the frame body portion of the optical scanner is formed thicker in the lower side in FIG. 8 than the base portion of the movable portion, and the permanent magnet is fixed to the lower surface of the frame body portion. The configuration of the part is not limited to this, and for example, the frame part may be formed to the same thickness as the base part. In this case, in order to avoid contact of the base with the permanent magnet fixed to the lower surface of the frame body portion, a concave portion (escape portion) may be formed on the upper surface of the permanent magnet.

  In the above-described embodiment, the case where the image display unit (the light source, the light combining unit, and the optical scanning unit) is provided along the side surface of the observer's head when in use is described as an example. However, the image display unit is used. It may be provided along the front of the observer's head at the time. In this case, the image display unit may be arranged so as to be positioned above or below the eyes of the observer at the time of use, or arranged so as to be located between the eyes of the observer at the time of use. Also good.

  In the above-described embodiment, the example in which the present invention is applied to the eyeglass-type head mounted display has been described. However, the image display device of the present invention is not limited to this, and other types such as a helmet type, a headset type, and the like. The present invention can be applied to a head-mounted image display device. Moreover, the image display apparatus of this invention may not be provided with the flame | frame with which a head is mounted | worn if it displays an image as a virtual image on an observer's eyes.

DESCRIPTION OF SYMBOLS 1 ... Image display device 2 ... Light source unit for drawing 3 ... Prism 4 ... Optical scanning part 5 ... Detection part 6 ... Control part 7 ... Frame 9 ... Case 10 ... Image display unit 21B ... Laser light source 21G Laser light source 21R Laser light source 22R Collimator lens 22G Collimator lens 22B Collimator lens 23 Photosynthesis unit 23B Dichroic mirror 23G Dichroic mirror 23R Dichroic Mirror 31 ... Incident surface 32 ... Output surface 40 ... Optical scanner 41 ... Movable part 43 ... Frame body part 45 ... Support part 46 ... Permanent magnet 47 ... Coil 48 ... Magnetic core 49 ... Voltage application Part 51 ... Light receiving element 71 ... Nose pad part 72 ... Front part 73 ... Temple part 4. Modern part 75 ... Rim part 76 ... Bridge part 79 ... Second member 81 ... Reflective member 82 ... Transparent member 91 ... Window part 92 ... First member 93 ... Pin 411 ... Base part 412 ... Spacer 413 ... Light reflector 414 ... Light reflector 414a ... Light reflector 415 ... Hard layer 421 ... Shaft 422 ... Shaft 441 ... Shaft 442 ... Shaft 443 ... Shaft part 444 ... Shaft part 491 ... First voltage generation part 492 ... Second voltage generation part 493 ... Voltage superposition part 493a ... Adder EA ... Ear EY ... Eye F ... Face H ... Head J1 ... First axis J2 ... Second axis J3 ... Axis LL ... Drawing laser beam NS ... Nose RR ... Laser beam GG ... Laser beam BB ... Laser beam S ... Drawable area S '... Effective drawing Area S "‥‥ non-imaging region T1 ‥‥ period T2 ‥‥ period V1 ‥‥ first voltage V2 ‥‥ second voltage alpha ‥‥ angle theta ‥‥ inclination angle

Claims (11)

A plurality of light source units that emit light;
A light combining unit that combines light emitted from the plurality of light sources;
An optical scanning unit that scans the light combined by the light combining unit;
The light source unit, the light combining unit, and the optical scanning unit are mounted, and the frame is mounted on the observer's head,
The optical path until the light emitted from the light source unit enters the optical scanning unit is on the same virtual plane,
The image display device according to claim 1, wherein the virtual plane is along a vertical direction of the head when the frame is attached to the head.   The image display apparatus according to claim 1, further comprising a housing that is supported by the frame and that houses the light source unit, the light combining unit, and the optical scanning unit.   The image display device according to claim 2, wherein the housing is rotatable with respect to the frame.   The image display device according to claim 2, wherein the housing has a flat shape along the virtual plane. The frame includes a front part and a temple part connected to the front part,
5. The image display device according to claim 1, wherein the light source unit, the light combining unit, and the optical scanning unit are mounted on the temple unit. 6.   The light scanning unit swings around each of the first axis and the second axis that intersect each other, and is provided with a light reflecting surface that reflects the light combined by the light combining unit 6. The image display device according to claim 1, further comprising a plate. The optical scanning unit includes a base that swings around the first axis and the second axis, and a spacer that connects the base and the light reflecting plate,
The image display device according to claim 6, wherein the light reflecting surface is perpendicular to the virtual plane when the light scanning unit is not driven.   The optical scanning section includes a frame body portion provided so as to surround the base portion, a first shaft portion that supports the base portion so as to be swingable around the first axis with respect to the frame body portion, The image display apparatus according to claim 7, further comprising: a second shaft portion that supports the frame body portion so as to be swingable around the second axis.   The image display according to claim 8, wherein the optical scanning unit includes a permanent magnet provided in the frame body part, and a coil that is disposed opposite to the frame body part and generates a magnetic field that acts on the permanent magnet. apparatus. An image display device used by being worn on the observer's head,
A plurality of light source units that emit light;
A light combining unit that combines light emitted from the plurality of light sources;
An optical scanning unit that scans the light combined by the light combining unit,
An image display in which an optical path until light emitted from the light source unit enters the optical scanning unit is on the same virtual plane along a side surface or a front surface of the head at the time of use. apparatus. A plurality of light source units that emit light;
A light combining unit that combines light emitted from the plurality of light sources;
An optical scanning unit that scans the light combined by the light combining unit;
The light source unit, the light combining unit, and the optical scanning unit are mounted, and the frame is mounted on the observer's head,
The optical path until the light emitted from the light source unit enters the optical scanning unit is on the same virtual plane,
The virtual plane is a head-mounted display that is along the vertical direction of the head when the frame is attached to the head.

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