JP4650227B2 - Optical scanning device and image display device - Google Patents

Description

The present invention relates to an optical scanning device and an image display device, and more particularly to a technology of an optical scanning device used for an image display device that displays an image by scanning a beam light modulated in accordance with an image signal.

In recent years, projectors and displays using laser light sources have been proposed with the increase in output of semiconductor lasers and the development of blue semiconductor lasers. Since the laser beam has a single wavelength, it has characteristics such as high color purity, high coherence, and easy shaping. By using a laser light source, it is considered possible to reduce the size and the number of components as compared with a conventional projector or the like.
For this reason, it is expected that a laser beam is used to display an image with high resolution and good color reproducibility with a small configuration. For example, Japanese Patent Application Laid-Open No. H10-228707 proposes a technique for achieving a configuration suitable for downsizing in an image display device that scans light beams. Patent Document 1 discloses a configuration in which a plurality of light beams are simultaneously scanned using a galvano mirror that reflects the light beams.

JP 2003-21804 A

In order to display an image by scanning with laser light, a high-power laser light source is used. In order to ensure the brightness of the image, in particular, as the screen becomes larger, higher output laser light is required. In the configuration proposed in Patent Document 1, a plurality of color lights from a plurality of light sources are concentrated on one reflection mirror. When the reflectance of the reflection mirror is low with respect to the laser beam, it is considered that the reflection mirror is deformed or burnt out due to heat absorbed by the reflection mirror. In order to reduce the deterioration of the reflecting mirror for high output laser light,
The reflectance of the reflecting mirror is desirably 99% or more, for example. On the other hand, it is extremely difficult to realize a high reflectance of about 99% for a plurality of lights having different wavelength regions.

Since the reflection mirror is supported by a rotating shaft such as a torsion spring, the heat stored in the reflecting mirror is released not only by propagation through the rotating shaft but also by divergence into the air. In order to efficiently release the heat accumulated in the reflecting mirror, it is conceivable to increase the size of the torsion spring. On the other hand, if the reflecting mirror becomes large as the torsion spring becomes large, it becomes difficult to perform high-speed and stable scanning of the laser light. From the viewpoint of scanning the laser beam stably and at high speed, it is desired to make the reflecting mirror small. On the other hand, it is considered that the concentration of each laser beam on the small reflecting mirror promotes the deterioration of the reflecting mirror. As described above, according to the conventional technique, there is a problem that it is difficult to scan the light beam with a small and highly reliable configuration. The present invention has been made in view of the above problems,
It is an object of the present invention to provide an optical scanning device and an image display device capable of scanning a light beam with a small and highly reliable configuration.

In order to solve the above-described problems and achieve the object, according to the present invention, there are provided a plurality of light source units that supply light beams of different colors and a scanning unit that scans the light beams from the light source units. The scanning unit includes a reflecting mirror provided for each color, and the reflecting mirror has a beam incident on the reflecting mirror in comparison with the beam light of another color different from the color of the beam light incident on the reflecting mirror. It is possible to provide an optical scanning device that reflects light with high reflectivity.

Different colors refer to having non-identical and non-approximate wavelength regions.
The reflection mirror can realize a high reflectance relatively easily for light in a narrow wavelength region. By providing a reflection mirror for each color, it is possible to allow only light beams in a wavelength region that can achieve high reflectivity to be incident on the reflection mirror, and to reduce the beam light absorbed by the reflection mirror. it can. By reducing the absorption of the beam light to the reflection mirror, heat accumulation in the reflection mirror can be reduced. By reducing the accumulation of heat in the reflection mirror, the deterioration of the reflection mirror can be reduced and high reliability can be obtained. In addition, since the reflecting mirrors are arranged corresponding to the light source units for the respective color lights, the light source units can be arranged with a higher degree of freedom compared with the case where each beam light is scanned by a single reflecting mirror. By improving the degree of freedom of configuration, it is possible to easily achieve a configuration suitable for downsizing. Thereby, an optical scanning device capable of scanning the light beam with a small and highly reliable configuration can be obtained.

According to a preferred aspect of the present invention, the reflecting mirror desirably has a dielectric multilayer film. By using the dielectric multilayer film, it is possible to make a configuration capable of reflecting the color light incident on the reflection mirror with high reflectance.

According to a preferred aspect of the present invention, the reflection mirror is provided on the metal layer that reflects the beam light from the light source unit, and on the side of the metal layer that reflects the beam light. And an increased reflection film formed with a film thickness corresponding to the wavelength region. By using the metal layer and the increased reflection film, the color light incident on the reflection mirror can be reflected with high reflectance. Furthermore, the increased reflection film can also function as a protective layer for protecting the metal layer. By providing the increased reflection film, deterioration of the reflection mirror can be reduced and high reliability can be obtained.

As a preferred embodiment of the present invention, it is desirable that the light source unit supplies the same color and a plurality of light beams. The same color means having the same or similar wavelength region. Thereby, the light quantity of each color light can be increased. In the present invention, the light beams having the same color can be reflected with high reflectance by the reflecting mirror. If the light beams have the same color, deterioration of the reflecting mirror can be reduced even if the light amount is increased, and high reliability can be maintained. Further, in the present invention, the light source unit and the reflection mirror can be arranged with a high degree of freedom. Therefore, even when a large array light source unit is used, the size can be easily reduced.

As a preferred aspect of the present invention, the scanning unit scans the beam light in the first direction, and the beam light from the first reflection mirror is substantially perpendicular to the first direction. A second reflection mirror that scans in the direction of the first reflection mirror, and the first reflection mirror is different from the color of the beam light incident on the first reflection mirror in comparison with the beam light of another color. It is desirable to reflect the beam light incident on the surface with high reflectivity. Thereby, the light beam can be scanned in the first direction and the second direction.

Moreover, as a preferable aspect of the present invention, it is desirable that more first reflection mirrors are provided than second reflection mirrors. Thereby, compared with the case where the same number of second reflection mirrors as the first reflection mirrors are provided, the number of parts can be reduced, and a more compact configuration can be achieved. Light beams with dispersed intensities are incident on the second reflecting mirror by scanning with the first reflecting mirror. For this reason, it is possible to reduce the deterioration of the second reflection mirror even if light beams of different colors are simultaneously incident on the second reflection mirror. Therefore, high reliability can be maintained.

Moreover, as a preferable aspect of the present invention, it is desirable that the second reflecting mirror is larger than the first reflecting mirror. Thereby, the beam light scanned in the first direction by the first reflecting mirror can be incident on the second reflecting mirror. Further, it is possible to sufficiently disperse the beam light with the large second reflection mirror, and further, it is possible to reduce the deterioration of the second reflection mirror. Therefore, higher reliability can be obtained. In the present invention, the laser beam can be reciprocated a plurality of times in the main scanning direction by the first reflection mirror while the beam beam is scanned once in the sub-scanning direction by the second reflection mirror. If high-speed driving of the second reflecting mirror is unnecessary, it can be considered that even if the second reflecting mirror is made large, the influence on the beam light scanning is small.

As a preferred aspect of the present invention, it is desirable that the reflection mirror scans the beam light in the first direction and in a second direction substantially orthogonal to the first direction. Thereby, the light beam can be scanned in the first direction and the second direction. By adopting a configuration in which beam light is scanned in two directions with a single reflection mirror, the number of components is reduced and the configuration is made smaller than when a combination of reflection mirrors that scan beam light in one direction is used. Can do.

As a preferred embodiment of the present invention, the scanning unit includes a polygon mirror, the reflection mirror scans the beam light from the light source unit in the first direction, and the polygon mirror receives the beam light from the reflection mirror. It is desirable to scan in a second direction substantially orthogonal to the first direction. Thereby, the light beam can be scanned in the first direction and the second direction.

Moreover, as a preferable aspect of the present invention, the polygon mirror rotates a plurality of mirror pieces and scans a plurality of light beams using one mirror piece directed to a specific side among the plurality of mirror pieces. Is desirable. In the case of such a configuration, by adjusting the incident angle of each beam light to one mirror piece directed to a specific side, it can be easily adjusted so that each beam light scans on the irradiated surface. . By scanning the beam light with the reflection mirror, the beam light from the reflection mirror is dispersed in the mirror piece of the polygon mirror. For this reason, it is possible to reduce deterioration of the polygon mirror even if light beams of different colors are simultaneously incident on one mirror piece. Therefore, high reliability can be maintained.

Moreover, as a preferable aspect of the present invention, the polygon mirror rotates a plurality of mirror pieces and scans a plurality of light beams using two or more mirror pieces directed to a specific side among the plurality of mirror pieces. It is desirable. With the configuration in which the beam light is incident on two or more mirror pieces, the light source unit and the reflection mirror can be separated for each color light. Thereby, the freedom degree of a structure can further be improved and it can be set as the structure suitable for size reduction. Further, it is possible to sufficiently disperse the beam light with two or more mirror pieces, and further, it is possible to reduce deterioration of the polygon mirror. Therefore, higher reliability can be obtained.

As a preferred aspect of the present invention, it is desirable that the scanning unit scans the beam light by causing the reflection mirror to resonate. Thereby, the amount of displacement of the reflection mirror can be increased, and the beam light can be efficiently scanned with less energy. In the present invention, since it is possible to reflect the color light incident on the reflection mirror with high reflectance, deterioration of the reflection mirror can be reduced even if the beam light is concentrated on a small reflection mirror. Therefore, high reliability can be maintained even when the light beam is scanned at high speed by resonating the small reflecting mirror.

Furthermore, according to the present invention, it is possible to provide an image display device characterized in that an image is displayed by scanning the light beam modulated in accordance with an image signal using the above optical scanning device. . By using the above-described optical scanning device, it is possible to scan the light beam with a small and highly reliable configuration. As a result, an image display apparatus capable of displaying an image with a small and highly reliable configuration can be obtained.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of an image display apparatus 10 according to Embodiment 1 of the present invention. Image display device 1
0 supplies laser light to the irradiated surface S which is one surface of the screen 18, and the screen 18
This is a so-called rear projector that observes an image by observing light emitted from the other surface. The image display device 10 displays an image by scanning the light beam modulated according to the image signal.

The image display device 10 includes an R light source unit 11R, a G light source unit 11G, and a B light source unit 1.
1B. The light source section 11R for R light is a red laser beam (hereinafter referred to as “R light”) that is beam light.
That's it. ). The G light source unit 11G is a green laser beam (hereinafter referred to as “beam light”).
It is called “G light”. ). The light source unit 11B for B light supplies blue laser light (hereinafter referred to as “B light”) that is beam light. As each color light source unit 11R, 11G, 11B,
For example, an edge emitting semiconductor laser can be used. Each color light source 11R, 11G
, 11B supply laser light modulated according to the image signal. As the modulation according to the image signal, either amplitude modulation or pulse width modulation may be used.

A first reflecting mirror 12R for R light is provided on the emission side of the light source unit 11R for R light. R
The first reflection mirror for light 12R receives the R light from the R light source unit 11R on the irradiated surface S.
Scan in the X direction, which is the first direction. A G light first reflection mirror 12G is provided on the light emission side of the G light source unit 11G. The first reflecting mirror 12G for G light is a light source unit 11G for G light.
The G light is scanned in the X direction, which is the first direction, on the irradiated surface S. A first reflection mirror 12B for B light is provided on the emission side of the light source unit 11B for B light. The first reflection mirror 12B for B light scans the B light from the light source unit 11B for B light in the X direction that is the first direction on the irradiated surface S. Thus, each 1st reflective mirror 12R, 12G, 12B is provided for every color. Each of the first reflection mirrors 12R, 12G, and 12B scans the laser beam by rotating around the rotation axis while reflecting the laser beam.

The 2nd reflective mirror 14 is provided in the position where the laser beam from each 1st reflective mirror 12R, 12G, 12B irradiates on the same area | region. The second reflection mirror 14 scans the laser light from the first reflection mirrors 12R, 12G, and 12B in the Y direction on the irradiated surface S. The Y direction is a second direction substantially orthogonal to the first direction. The second reflection mirror 14 scans the laser beam by rotating about the rotation axis while reflecting the laser beam. Each of the first reflecting mirrors 12R, 12G, 12B and the second reflecting mirror 14 may be driven by an electrostatic force corresponding to a potential difference, or may be driven by using a stretching force or an electromagnetic force of a piezoelectric element. it can.

In this embodiment, since one second reflection mirror 14 is used for the three first reflection mirrors 12R, 12G, and 12B, three second reflection mirrors corresponding to the first reflection mirrors 12R, 12G, and 12B are used. The number of parts can be reduced as compared with the case of using, and the configuration can be made smaller. In addition, it is not restricted to the structure which provides the one 2nd reflective mirror 14 with respect to the three 1st reflective mirrors 12R, 12G, and 12B. Any structure may be used as long as the first reflecting mirror is provided more than the second reflecting mirror.

Each of the first reflection mirrors 12R, 12G, and 12B and the second reflection mirror 14 is a scanning unit that scans the laser beams from the light source units 11R, 11G, and 11B for the respective color lights. Light source unit 1 for each color light
1R, 11G, 11B and the scanning unit constitute an optical scanning device 20. The image display device 10
An image is displayed by scanning the laser beam modulated according to the image signal using the optical scanning device 20.

Light from the second reflecting mirror 14 enters the reflecting portion 15. The reflection unit 15 reflects the laser light from the second reflection mirror 14 toward the screen 18. The screen 18 has a housing 17.
Are provided on the observer side. The housing 17 seals the space inside the housing 17. The screen 18 is a transmissive screen that transmits laser light modulated in accordance with an image signal. The screen 18 includes, for example, a Fresnel lens that converts the angle of light toward the viewer, a lenticular lens that diffuses light, a diffuser plate that has light diffusibility (all not shown), and the like. The observer observes the image by observing the light emitted from the screen 18.

FIG. 2 illustrates scanning of laser light from each color light source unit 11R, 11G, 11B. In FIG. 2, for the sake of convenience, illustration of components unnecessary for description is omitted. Each of the first reflecting mirrors 12R, 12G, and 12B reciprocates the laser light in the X direction, while the second
The reflection mirror 14 repeats flyback scanning in which the laser beam is scanned in one direction, for example, only in the downward direction in the Y direction. The second reflecting mirror 14 is Y during one frame period of the image.
While the laser beam is scanned once in the direction, each of the first reflection mirrors 12R, 12G, and 12B
The laser beam is reciprocated several times in the direction.

It is desirable to use the resonance operation of each of the first reflecting mirrors 12R, 12G, and 12B for scanning the laser beam in the X direction. Each of the first reflecting mirrors 12R, 12G, and 12B can increase the amount of displacement by resonating. By increasing the displacement amount of each of the first reflecting mirrors 12R, 12G, and 12B, it is possible to scan the laser beam with less energy and at high speed. From the viewpoint of scanning the laser beam stably and at high speed, the first reflecting mirrors 12R, 1R, 1
2G and 12B are as small as possible. The first reflecting mirrors 12R, 12G, 1
2B may be configured to reciprocate and rotate by an operation other than the resonance operation.

The second reflection mirror 14 is formed to be larger than the first reflection mirrors 12R, 12G, and 12B to such an extent that laser light that is scanned in the X direction by the first reflection mirrors 12R, 12G, and 12B can be made incident. ing. Since the second reflection mirror 14 is used for scanning the laser beam in the sub-scanning direction, the drive can be performed at a lower speed than the first reflection mirrors 12R, 12G, and 12B. Therefore, it can be considered that even if the second reflecting mirror 14 is made large, the influence on the scanning of the laser light is small.

Each of the first reflection mirrors 12R, 12G, and 12B is configured, for example, by forming a dielectric multilayer film on a surface that reflects laser light in a substrate that is a parallel plate. The dielectric multilayer film formed on the first reflection mirror 12R for R light is compared with other color light different from R light,
R light incident on the first reflecting mirror 12R for R light is reflected with a high reflectance. The first reflection mirror for G light 12G is configured to reflect the G light incident on the first reflection mirror for G light 12G with a higher reflectance than other color light different from the G light. The first reflection mirror 12B for B light is different from the other color light different from the B light, and the first reflection mirror 12 for B light.
It is configured to reflect B light incident on B with a high reflectance.

The dielectric multilayer film is configured by alternately stacking high refractive index layers and low refractive index layers. By superimposing a high refractive index layer and a low refractive index layer formed with an optical thickness of about one-fourth of a specific wavelength, it is possible to reflect light of this specific wavelength with the maximum reflectance. It becomes. In order to widen the wavelength region of light having high reflectivity, it is conceivable to provide a layer having a continuously variable thickness in addition to a plurality of layers having different thicknesses. However, when the wavelength region including all of R, G, and B is reflected by one dielectric multilayer film, the reflectance is likely to be uneven as shown in FIG. For this reason, for a plurality of lights having different wavelength regions, 9
It is extremely difficult to achieve a high reflectance of about 9%.

FIG. 4 illustrates the reflection characteristics of the dielectric multilayer film used for each of the first reflection mirrors 12R, 12G, and 12B. Here, the relationship between the reflectance and the wavelength is shown by taking a dielectric multilayer film used for the first reflection mirror 12G for G light as a representative example. The dielectric multilayer film can realize a high reflectivity relatively easily for light in a narrow wavelength region including one color light. For example, assuming that the wavelength of G light from the G light source unit 11G is 527 nm, the dielectric multilayer film provided on the first G light reflecting mirror 12G is nearly 100% in a narrow wavelength region centered at 527 nm. It is formed to have a reflectance. The R light first reflection mirror 12R and the B light first reflection mirror 12B are also formed so as to have a reflectance close to 100% for the B light.

By providing the first reflection mirrors 12R, 12G, and 12B for each color, it is possible to allow only the laser light in the wavelength region that can realize high reflectance to be incident on the first reflection mirrors 12R, 12G, and 12B. And the laser light absorbed by the first reflecting mirrors 12R, 12G, and 12B can be reduced. Note that the reflection characteristics of the dielectric multilayer film described with reference to FIG. 4 may vary depending on the incident angle of the laser beam to the dielectric multilayer film. For this reason, even when a single wavelength laser beam is used, it is desirable to provide a certain width in the wavelength region where the reflectance is high. Thereby, the incident angle of the laser beam is set to the first reflection mirrors 12R and 12G.
Even when it changes due to the vibration of 12B, a high reflectance can be maintained.

In the present invention, even if the laser light is concentrated on the small first reflection mirrors 12R, 12G, and 12B, the first reflection mirror is reduced by reducing the laser light absorbed by the first reflection mirrors 12R, 12G, and 12B. Accumulation of heat in 12R, 12G, and 12B can be reduced. By reducing the accumulation of heat in the first reflecting mirrors 12R, 12G, and 12B, it is possible to reduce deterioration due to deformation, burnout, and the like of the first reflecting mirrors 12R, 12G, and 12B with respect to high output laser light. .

Whereas each of the first reflection mirrors 12R, 12G, and 12B uses a dielectric multilayer film, the second reflection mirror 14 is made of, for example, aluminum or silver on the surface of the parallel plate that reflects the laser light. It can be configured by forming a metal thin film. To the second reflecting mirror 14, the first
Laser beams with dispersed intensities are incident upon scanning by the reflection mirrors 12R, 12G, and 12B. The large second reflection mirror 14 can sufficiently disperse the beam light. For this reason, even if the 2nd reflective mirror 14 is a structure which reflects the laser beam of a mutually different color with a metal thin film, it is possible to reduce deterioration.

As described above, the image display apparatus 10 can obtain high reliability by reducing the deterioration of the first reflection mirrors 12R, 12G, and 12B and the second reflection mirror 14. Also,
The first reflecting mirrors 12R, 12G, 1 are associated with the color light source units 11R, 11G, 11B.
Compared with the case where each laser beam is scanned by a single reflecting mirror to arrange 2B,
The light source units 11R, 11G, and 11B can be arranged with a high degree of freedom. By improving the degree of freedom of configuration, it is possible to easily achieve a configuration suitable for downsizing. This produces an effect that an image can be displayed with a small and highly reliable configuration.

FIG. 5 illustrates an optical scanning device 50 according to the first modification of the present embodiment. The optical scanning device 50 can be applied to the image display device 10 described above. The R light scanning unit 54R scans the R light from the R light source unit 11R. The G light scanning section 54G is a G light source section 1.
G light from 1G is scanned. The B light scanning unit 54B scans the B light from the B light source unit 11B. Each of the scanning units 54R, 54G, and 54B has a so-called double gimbal structure including a reflection mirror 52 and an outer frame portion 53 provided around the reflection mirror 52.

The reflection mirror 52 transmits the laser beam to the X axis by a rotation axis between the reflection mirror 52 and the outer frame portion 53.
Rotate to scan in the direction. The outer frame portion 53 rotates together with the reflection mirror 52 so as to scan the laser light in the Y direction. With this configuration, the reflection mirror 52 scans the laser light in the X direction and the Y direction. By adopting a configuration in which the laser beam is scanned in two directions with one reflection mirror 52, the number of components is reduced and the configuration is made smaller than when a combination of reflection mirrors that scan the laser beam in one direction is used. be able to.

The reflection mirror 52 is provided with a dielectric multilayer film. The dielectric multilayer film provided on the reflection mirror 52 of the R light scanning unit 54R is formed so as to reflect the R light with a higher reflectance than other color lights other than the R light. The dielectric multilayer film provided on the reflection mirror 52 of the G light scanning unit 54G is formed so as to reflect the G light with a higher reflectance than other color lights other than the G light. The dielectric multilayer film provided on the reflection mirror 52 of the B light scanning section 54B is formed so as to reflect the B light with a higher reflectance than other color lights other than the B light. Also in this modified example, the laser beam can be scanned with a small and highly reliable configuration.

FIG. 6 illustrates an optical scanning device 60 according to the second modification of the present embodiment. The optical scanning device 60 can be applied to the image display device 10 described above. The optical scanning device 60 includes a polygon mirror 64 provided at a position where the laser beams from the first reflection mirrors 12R, 12G, and 12B are incident. The polygon mirror 64 scans the laser beams from the first reflection mirrors 12R, 12G, and 12B in the Y direction by rotating the plurality of mirror pieces 65 around the rotation axis 66. The first reflecting mirrors 12R, 12G, and 12B and the polygon mirror 64 are scanning units that scan the laser beams from the color light source units 11R, 11G, and 11B. The polygon mirror 64 repeats flyback scanning in which the laser beam is scanned in one direction, for example, only in the downward direction in the Y direction.

The polygon mirror 64 is one of the plurality of mirror pieces 65 directed to the screen 18 side.
Each color light is scanned using two mirror pieces 65. In the case of such a configuration, the irradiated surface S is adjusted by adjusting the incident angle of each color light to one mirror piece 65 directed to the screen 18 side.
It can be easily adjusted so that each color light scans. In the mirror piece 65, laser light with dispersed intensity is incident upon scanning by the first reflecting mirrors 12R, 12G, and 12B. Therefore, the polygon mirror 64 transmits laser beams of different colors to one mirror piece 65.
It is possible to reduce the deterioration even if the light is incident simultaneously on the surface. Also in this modified example, the laser beam can be scanned with a small and highly reliable configuration.

The optical scanning device is not limited to the configuration in which each color light is scanned using one mirror piece 65 directed to a specific side of the polygon mirror 64. For example, each color light may be scanned using two mirror pieces 65 of the polygon mirror 64 directed toward the screen 18 as in the optical scanning device 70 shown in FIG. The optical scanning device 70 includes R light from the first mirror 12R for R light,
And the G light from the first mirror 12G for G light is incident on one mirror piece 65. The B light from the first B light mirror 12B is incident on the mirror piece 65 adjacent to the mirror piece 65 on which the R light and the G light are incident. Thereby, the light source part 11B for B light and the 1st reflective mirror 12B for B light
Are arranged at positions away from the other light source units 11R and 11G and the other first reflection mirrors 12R and 12G. Furthermore, each color light may be scanned using three mirror pieces 65. In this case, R light, G light, and B light are configured to enter different mirror pieces 65.

By adopting a configuration in which laser light is incident on two or more mirror pieces 65, the light source units 11R and 11
G and 11B and the first reflecting mirrors 12R, 12G, and 12B can be arranged separately for each color light. Thereby, the freedom degree of a structure can further be improved and it can be set as the structure suitable for size reduction. Further, it is possible to sufficiently disperse the laser light by the two or more mirror pieces 65, and it is possible to further reduce the deterioration of the polygon mirror 64. In addition,
The configuration is not limited to the configuration in which the laser beam is incident on the mirror piece 65 directed toward the screen 18 side, and the laser beam may be incident on the mirror piece 65 directed in a direction other than the direction of the screen 18.

Each of the above optical scanning devices is not limited to a configuration that scans one laser beam for each color.
For example, the same color and a plurality of laser beams can be scanned. The amount of light of each color can be increased by scanning the same color and a plurality of laser beams. For example, as the light source unit for each color light, as shown in FIG. 8, an array light source unit 81 that supplies five laser beams of the same color from five light emitting units 82 can be used. The same color means having the same or similar wavelength region. As the array light source unit 81, for example, a surface emitting semiconductor laser can be used.

The array light source unit 81 advances the five laser beams substantially in parallel. The intervals between the five laser beams from the array light source unit 81 are narrowed by the converging action by the convex lens 83 and the diffusing action by the concave lens 84. In this way, a configuration can be adopted in which a plurality of laser beams of the same color are incident on a small reflection mirror. In addition, it is not restricted to the structure which narrows the space | interval about the same color and a several laser beam, For example, it is good also as a structure condensed with a reflective mirror. Further, the combination of a plurality of laser beams is not limited to the case where the convex lens 83 and the concave lens 84 are used, and another lens system may be used. Further, when the interval between the plurality of laser beams can be reduced to a certain extent that the light can enter the reflecting mirror, the convex lens 83 and the concave lens 84 may be omitted. Furthermore, as the array light source unit 81, a plurality of edge-emitting semiconductor lasers that supply laser beams of the same color may be used.

In the present invention, it is possible to reflect laser beams having the same color with a high reflectance by the reflection mirror, so that even if the amount of beam light incident on the reflection mirror is increased, deterioration of the reflection mirror is reduced. High reliability can be maintained. In the present invention, each color light source 11R,
Since 11G and 11B can be arranged with a high degree of freedom, a large array light source unit 81 is provided.
Even if it is a case where it uses, size reduction can be achieved easily.

Further, the reflection mirror provided corresponding to each color light is not limited to the configuration using the dielectric multilayer film. The reflection mirror may be configured to use a metal layer and an increased reflection film. The reflection mirror 92 whose cross-sectional configuration is shown in FIG. 9 is configured by sequentially laminating a substrate 93, a metal layer 94, and an increased reflection film 95. The metal layer 94 is formed on the surface of the substrate 93 that is a parallel plate on the side that reflects the laser light. The metal layer 94 reflects the laser light from the light source unit. The increased reflection film 95 is
The metal layer 94 is provided on the side that reflects the laser beam.

The metal layer 94 can be configured using any of highly reflective metal members such as neodymium silver, silver, gold, and aluminum. The increased reflection film 95 can be configured using a strong and highly stable transparent member, for example, Si ₂ O ₃ . The increased reflection film 95 can be formed with an optical thickness that is approximately a quarter of the wavelength of the laser light incident on the reflection mirror 92. In this case, the light L1 reflected at the interface between the increased reflection film 95 and the air and the light L2 reflected at the interface between the increased reflection film 95 and the metal layer 94 have the same phase, and the laser beam can be reflected with a high reflectance. It becomes possible.

FIG. 10 shows the reflection characteristic R1 when only the metal layer 94 is used, and the metal layer 94 and the increased reflection film 9.
The reflection characteristic R2 when 5 is used is shown. When the metal layer 94 is used, it is possible to obtain a reflectivity of about 90% or less for light in a relatively wide wavelength region. In contrast, the metal layer 9
By laminating the reflective reflection film 95 on 4, a high reflectance of about 97% can be realized for light in a narrow wavelength region including one color light.

In this way, by forming the increased reflection film 95 with a film thickness corresponding to the wavelength region of the laser light reflected by the reflection mirror 92, the color light incident on the reflection mirror 92 can be reflected with high reflectance. Can do. Therefore, even when the metal layer 94 and the increased reflection film 95 are used, high reliability can be obtained. Further, the increased reflection film 95 can function as a protective layer for protecting the metal layer 94. By providing the increased reflection film 95, corrosion of the metal layer 94 and adhesion of scratches can be prevented, and deterioration of the reflection mirror 92 can be reduced. Thereby, higher reliability can be obtained.

FIG. 11 shows a schematic configuration of an image display apparatus 110 according to the second embodiment of the present invention. The image display device 110 supplies laser light to a screen 115 provided on the observer side, and the screen 1
This is a so-called front projection type projector in which an image is viewed by observing light reflected at 15. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The laser light from the optical scanning device 20 passes through the emission window 111 and then enters the screen 115. In the case of this embodiment as well, as in the first embodiment, an image can be displayed with a small and highly reliable configuration.

In the above embodiment, each color light source unit uses a semiconductor laser. However, the present invention is not limited to this as long as it can supply beam-shaped light. For example, each color light source unit may be configured to use a solid laser, a liquid laser, or a gas laser.

As described above, the optical scanning device according to the present invention is suitable for use in an image display device that displays an image by scanning a plurality of light beams modulated according to an image signal.

1 is a diagram illustrating a schematic configuration of an image display apparatus according to Embodiment 1 of the present invention. The figure explaining the scanning of the laser beam from the light source part for each color light. The figure explaining the relationship between the reflectance and wavelength of a dielectric multilayer film. The figure explaining the reflective characteristic of the dielectric multilayer film used for a 1st reflective mirror. FIG. 6 is a diagram illustrating an optical scanning device according to a first modification of the first embodiment. FIG. 6 is a diagram illustrating an optical scanning device according to a second modification of the first embodiment. The figure explaining the structure which scans each color light using two mirror pieces. The figure which shows the structure for making the same color and several laser beams enter into a reflective mirror. The figure which shows the cross-sectional structure of a reflective mirror provided with a metal layer and a reflective reflection film. The figure explaining a reflection characteristic. FIG. 5 is a diagram illustrating a schematic configuration of an image display device according to a second embodiment of the invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image display apparatus, 11R R light source part, 11G G light source part, 11B B light source part, 12R R light 1st reflective mirror, 12G G light 1st reflective mirror, 12B B light 1st Reflective mirror, 14 Second reflective mirror, 15 Reflector, 17 Housing, 18 Screen, 20 Optical scanning device, S Irradiated surface, 50 Optical scanner, 52 Reflective mirror, 53 Outer frame, 54RR light scanning unit , 54G G light scanning unit, 54B B light scanning unit, 60 light scanning device, 64 polygon mirror, 65 mirror piece, 66 rotation axis, 70 light scanning device,
81 Array light source unit, 82 Light emitting unit, 83 Convex lens, 84 Concave lens, 92 Reflection mirror, 93 Substrate, 94 Metal layer, 95 Intensive reflection film, 110 Image display device, 111 Exit window, 115 screen

Claims (13)

A plurality of light source sections for supplying light beams of different colors;
A scanning unit that scans the beam light from the light source unit,
The scanning unit includes a reflection mirror provided for each color,
The reflection mirror reflects the beam light incident on the reflection mirror with a high reflectance as compared with a beam light of another color different from the color of the beam light incident on the reflection mirror. Optical scanning device.   The optical scanning device according to claim 1, wherein the reflection mirror includes a dielectric multilayer film. The reflection mirror is
A metal layer that reflects the light beam from the light source unit;
An increased reflection film provided on a side of the metal layer that reflects the light beam and having a thickness corresponding to a wavelength region of the light beam that is reflected by the reflection mirror. Item 4. The optical scanning device according to Item 1. The optical scanning device according to any one of claims 1 to 3,
The light source unit includes a plurality of light emitting units that supply light of the same color,
The optical beam scanning apparatus according to claim 1, wherein the beam light is obtained by converging or condensing light from a plurality of light emitting units that supply the light of the same color . The optical scanning device according to any one of claims 1 to 4,
The reflection mirror scans the beam light from the light source unit in a first direction,
It said scanning unit, before the light beam from Kihan morphism mirror, said first direction to further optical scanning device you further comprising a second reflection-mirror which scans in a second direction substantially perpendicular . Before Kihan morphism mirror, an optical scanning apparatus according to claim 5, characterized in that it is provided more than the second reflecting mirror. The second reflecting mirror, an optical scanning device according to claim 5 or 6, characterized in that before a large than Kihan morphism mirror.   5. The light according to claim 1, wherein the reflection mirror scans the beam light in a first direction and a second direction substantially orthogonal to the first direction. 6. Scanning device. The scanning unit includes a polygon mirror,
The reflection mirror scans the beam light from the light source unit in a first direction,
5. The optical scanning according to claim 1, wherein the polygon mirror scans the beam light from the reflection mirror in a second direction substantially orthogonal to the first direction. 6. apparatus.   The polygon mirror rotates a plurality of mirror pieces, and scans the plurality of light beams using one mirror piece directed to a specific side among the plurality of mirror pieces. The optical scanning device according to 1.   The polygon mirror rotates a plurality of mirror pieces, and scans the plurality of beam lights by using two or more mirror pieces directed to a specific side among the plurality of mirror pieces. 9. The optical scanning device according to 9.   The optical scanning device according to claim 1, wherein the scanning unit scans the beam light by causing the reflection mirror to resonate.   An image display device, wherein an image is displayed by scanning the light beam modulated in accordance with an image signal using the optical scanning device according to claim 1.

Images