JP2007047245A - Light source apparatus, optical scanner and image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source apparatus which synthesizes a plurality of light beams, particularly the light beams from a plurality of light source parts having the same or similar wavelength region, to provide an optical scanner which stably scans the light beams at high speed by using the light source apparatus, and to provide an image display apparatus. <P>SOLUTION: The light source apparatus has: a first light source part 11 and a second light source apparatus 12 which supply a plurality of light beams which are linear polarized light beams having the same color; and a polarized beam splitter 15 which is a polarized light synthesizing part which synthesizes the light beam from the first light source part 11 and the light beam from the second light source 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  In recent years, a laser projector using laser light has been proposed as an image display device for displaying an image. Laser light is characterized by high monochromaticity and directivity. For this reason, the laser projector has an advantage that an image with good color reproducibility can be obtained. A technique for supplying light from a plurality of light emitting units has been proposed for an illumination device used in an image display device (see, for example, Patent Document 1).

JP 11-352589 A

  When the laser projector is configured to scan the laser light from multiple light source units, the specs are compared to the case where the amount of laser light on the irradiated surface is increased and the laser light from a single light source unit is superimposed. It is also possible to reduce the generation of water. In order to supply a plurality of laser beams, if the laser beams from a plurality of light source units are simply brought close to each other, the width for paralleling the laser beams increases, and therefore it is necessary to increase the size of the scanner that scans the laser beams. Arise. Large scanners are very difficult to drive stably and at high speed. For this reason, it is desired that the laser beams from the plurality of light source units can be emitted in a substantially matched manner. In order to synthesize light from a plurality of light source units so that the light rays are substantially matched, for example, it is conceivable to use a dichroic mirror. However, when the wavelength regions of the laser beams from the respective light source units are the same or approximate, it is a problem because it is very difficult to synthesize a plurality of laser beams using a dichroic mirror. The present invention has been made in view of the above-described problem, and a light source device capable of synthesizing a plurality of light beams, particularly light beams from a plurality of light source units having the same or similar wavelength regions, and a light source device therefor. It is an object of the present invention to provide an optical scanning device and an image display device that can scan a beam light stably and at high speed.

  In order to solve the above-described problems and achieve the object, according to the present invention, a first light source unit and a second light source unit that supply a plurality of light beams that are linearly polarized light of the same color, and from the first light source unit It is possible to provide a light source device including a polarized light combining unit that combines the beam light and the beam light from the second light source unit.

  Here, the light of the same color is assumed to be light having wavelength regions that are substantially the same or approximate. As the polarized light combining unit, for example, a polarized beam splitter that transmits polarized light in the first vibration direction and reflects polarized light in the second vibration direction substantially orthogonal to the first vibration direction can be used. By making the light beams from the first light source unit and the second light source unit incident on the polarized light combining unit as polarized light in the vibration direction according to the transmission characteristics and reflection characteristics of the polarized light combining unit, the light beams from the first light source unit In addition, the light beams from the second light source unit can be combined. The polarized light combining unit synthesizes the beam light from the first light source unit and the beam light from the second light source unit so as to be emitted or condensed substantially in parallel. The light beam from the first light source unit and the second light source unit are superposed so that the light beam from the first light source unit and the light beam from the second light source unit are substantially matched or alternately arranged in parallel using the polarized light combining unit. Can be handled in the same way as if the light from the light source is supplied from one light source unit. As a result, a light source device capable of synthesizing a plurality of light beams, in particular, light beams from a plurality of light source units whose wavelength regions are the same or approximate to each other can be obtained. If light beams from a plurality of light source units can be combined, the width in which the light beams are arranged in parallel can be made substantially the same as when a single light source unit is used.

  According to a preferred aspect of the present invention, it is desirable that the polarized light combining unit combine the beam light from the first light source unit and the beam light from the second light source unit so as to emit substantially in parallel. Thereby, the beam light from the first light source unit and the beam light from the second light source unit can be combined.

  According to a preferred aspect of the present invention, it is desirable that the polarized light combining unit combine the beam light from the first light source unit and the beam light from the second light source unit so as to collect them. Thereby, the beam light from the first light source unit and the beam light from the second light source unit can be combined.

  According to a preferred aspect of the present invention, the polarized light combining unit transmits the polarized light in the first vibration direction and reflects the polarized light in the second vibration direction substantially orthogonal to the first vibration direction. It is desirable to combine the light beams. By using such a polarized light combining unit, it is possible to superimpose the light beam from the first light source unit and the light beam from the second light source unit so as to be substantially coincident or alternately arranged in parallel. Thereby, the beam light from the first light source unit and the beam light from the second light source unit can be combined.

  According to a preferred aspect of the present invention, the first light source unit and the second light source unit are arranged so that the optical axis of the first light source unit and the optical axis of the second light source unit are substantially orthogonal, and the polarized light combining unit is And a polarizing film that transmits polarized light in the first vibration direction and reflects polarized light in the second vibration direction, and the polarizing film is one of the optical axis of the first light source unit and the optical axis of the second light source unit. Also, it is desirable to be arranged so as to be inclined at approximately 45 degrees. By disposing the polarizing film so as to be inclined at approximately 45 degrees with respect to both the optical axis of the first light source unit and the optical axis of the second light source unit, the optical axis of the first light source unit on the emission side of the polarized light combining unit. And the optical axis of the second light source unit can be substantially matched. Thereby, the beam light from the first light source unit and the beam light from the second light source unit can be combined.

  Moreover, as a preferable aspect of the present invention, it is desirable to have a phase plate provided between the first light source unit and the polarized light combining unit or between the second light source unit and the polarized light combining unit. For example, in the case of using a first light source unit and a second light source unit that both supply polarized light in the first vibration direction, a λ / 2 phase plate is provided between the second light source unit and the polarized light combining unit. To do. The polarized light in the first vibration direction from the second light source unit is converted into polarized light in the second vibration direction and enters the polarized light combining unit. As described above, by appropriately arranging the phase plate, it becomes possible to supply the beam light so as to match the transmission and reflection characteristics of the polarized light combining unit. Thereby, beam light can be combined according to the polarization characteristic of the light source unit.

  In a preferred aspect of the present invention, the first light source unit supplies beam light that is polarized light in the first vibration direction, and the second light source unit is beam light that is polarized light in the second vibration direction. It is desirable to supply Thus, the light beam from the first light source unit and the light beam from the second light source unit can be combined with a simple configuration without using a phase plate.

  As a preferred aspect of the present invention, it is desirable that the polarized light combining unit synthesizes the light beam of the light beam from the first light source unit and the light beam of the beam light from the second light source unit approximately coincident with each other. As a result, the same number of bright light beams can be supplied as when a single light source unit is used. Further, by combining the light beams from the two light source units, it is also possible to reduce the generation of speckle as compared with the case of combining the light beams from the single light source units.

  As a preferred aspect of the present invention, it is desirable that the polarized light combining unit synthesizes the beam of light from the first light source unit and the beam of light from the second light source unit alternately in parallel. As a result, it is possible to supply the light beam without greatly changing the width in which the light beams are arranged in parallel with the case where a single light source unit is used.

  Moreover, as a preferable aspect of the present invention, a first polarized light synthesizer for synthesizing the first color light, a second polarized light synthesizer for synthesizing the second color light, and the first color light and the second polarized light from the first polarized light synthesizer. It is desirable to have a color combining unit that combines the second color light from the light combining unit. Thereby, the light beams which are a plurality of color lights can be combined.

  Furthermore, according to the present invention, it is possible to provide an optical scanning device including the light source device described above and a scanning unit that scans light from the light source device. By using the above light source device, it is possible to scan the light beam synthesized by the light source device. In addition, since the width in which the light beams are arranged in parallel can be made substantially the same as when a single light source unit is used, a small scanning unit can be used. As a result, the beam light synthesized by the light source device can be scanned stably and at high speed. When laser light from a plurality of light source units is scanned, a configuration in which laser light is scanned by a plurality of scanning units provided for each light source unit is also conceivable. On the other hand, in this aspect, since the scanning unit can be downsized and a single scanning unit can be used, the optical system can be configured simply.

  In a preferred aspect of the present invention, the illumination optical system is provided between the light source device and the scanning unit, and the illumination optical system emits a plurality of light beams substantially parallel and emitted from the light source device. It is desirable to emit at different intervals. Thereby, the beam light combined by the light source device can be scanned at a desired interval.

  Moreover, as a preferable aspect of the present invention, it is desirable to have an illumination optical system provided between the light source device and the scanning unit, and it is desirable that the illumination optical system collects a plurality of light beams. By condensing a plurality of light beams by the illumination optical system, the scanning unit can be further reduced in size. Further, the light beam can be scanned at a desired interval on the irradiated surface.

  Furthermore, according to the present invention, there is provided an image display device for displaying an image by light from an optical scanning device, wherein the optical scanning device is the optical scanning device described above. Can do. By using the above optical scanning device, the light beam synthesized by the light source device can be scanned stably and at high speed. Thereby, an image display device capable of displaying a bright and high-quality image 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 a light source device 10 according to Embodiment 1 of the present invention. The light source device 10 includes a first light source unit 11 and a second light source unit 12. The first light source unit 11 and the second light source unit 12 supply four light beams having the same color, for example, red linearly polarized light. The light of the same color is light having wavelength regions that are substantially the same or approximate. The first light source unit 11 and the second light source unit 12 both supply p-polarized light that is polarized light in the first vibration direction.

  As the first light source unit 11 and the second light source unit 12, a surface emitting semiconductor laser that supplies laser light that is beam light can be used. The first light source unit 11 is disposed with the optical axis directed in the emission direction of the light source device 10. The first light source unit 11 and the second light source unit 12 are arranged so that the optical axis of the first light source unit 11 and the optical axis of the second light source unit 12 are substantially orthogonal. In the figure, solid line arrows and broken line arrows indicate laser light emitted from the first light source unit 11 in the direction along the optical axis of the first light source unit 11, and light from the second light source unit 12 to the second light source unit 12, respectively. The laser beam emitted in the direction along the axis is shown.

  The polarization beam splitter 15 is provided at a position where the laser light from the first light source unit 11 and the laser light from the second light source unit 12 are incident. The polarization beam splitter 15 is a prism body including a polarizing film 16 and is a polarization light combining unit that combines the laser light from the first light source unit 11 and the laser light from the second light source unit 12 so as to be emitted substantially in parallel. is there. The polarizing film 16 transmits p-polarized light that is polarized light in the first vibration direction and reflects s-polarized light that is polarized light in the second vibration direction. As the polarizing film 16, for example, a dielectric multilayer film can be used. The polarizing beam splitter 15 is disposed so that the polarizing film 16 is inclined at approximately 45 degrees with respect to both the optical axis of the first light source unit 11 and the optical axis of the second light source unit 12. A λ / 2 phase plate 14 is provided on the optical path between the second light source unit 12 and the polarization beam splitter 15.

  The p-polarized light from the first light source unit 11 passes through the polarizing film 16 of the polarization beam splitter 15 and then proceeds as it is in the emission direction. The p-polarized light from the second light source unit 12 is converted into s-polarized light by rotating the vibration direction by 90 degrees by the λ / 2 phase plate 14. The laser light from the second light source unit 12 is converted into s-polarized light and then enters the polarization beam splitter 15. In addition, it is desirable to provide an antireflection film on the incident surface on the first light source unit 11 side and the incident surface on the second light source unit 12 side of the polarization beam splitter 15. By providing the antireflection film, the light from each of the light source units 11 and 12 can be efficiently incident on the polarization beam splitter 15.

  The s-polarized light incident on the polarization beam splitter 15 from the second light source unit 12 side is reflected by the polarizing film 16, so that the optical path is bent approximately 90 degrees. The s-polarized light reflected by the polarizing film 16 travels in the same emission direction as the p-polarized light from the first light source unit 11 that has passed through the polarizing film 16. Since the polarizing film 16 is disposed so as to be inclined at approximately 45 degrees with respect to both the optical axis of the first light source unit 11 and the optical axis of the second light source unit 12, the first is formed on the emission side of the polarizing beam splitter 15. The optical axis of the light source unit 11 and the optical axis of the second light source unit 12 can be substantially matched.

  With this configuration, it is possible to emit the four laser beams from the first light source unit 11 and the four laser beams from the second light source unit 12 in a substantially identical manner. Therefore, as shown in FIG. 2, the light source device 10 forms four spots SP on the irradiated surface I with the laser light from the first light source unit 11 and the laser light from the second light source unit 12. A case where only one of the first light source unit 11 and the second light source unit 12 is used by substantially matching the light beam of the laser light from the first light source unit 11 and the light beam of the laser light from the second light source unit 12; It is possible to supply the same number of laser beams with approximately twice the brightness.

  In this way, the polarization beam splitter 15 which is a polarized light combining unit combines the laser light from the first light source unit 11 and the laser light from the second light source unit 12 so as to be emitted in a substantially parallel and substantially coincident manner. . This produces an effect that a plurality of light beams, in particular, light beams from a plurality of light source units 11 and 12 whose wavelength regions are the same or approximate can be combined. If the laser beams from the plurality of light source units 11 and 12 can be combined, it is possible to increase the amount of the laser beam on the irradiated surface as compared with the case of using a single light source unit. Furthermore, it is configured to supply a plurality of laser beams, and the laser beams from the plurality of light source units 11 and 12 are superposed to reduce the coherence between the laser beams, thereby reducing the generation of speckles. It becomes possible.

  If the laser beams from the plurality of light source units 11 and 12 can be combined, the laser beams can be arranged in parallel at substantially the same width as when a single light source unit is used. For example, the laser light from the light source device 10 can be scanned by a small scanning unit. Therefore, the light source device 10 of the present invention is useful when used in an optical scanning device that scans laser light.

  The polarization beam splitter 15 may be configured to transmit s-polarized light and reflect p-polarized light. In this case, the light source device 10 can be configured to emit laser light in a direction in which the laser light from the second light source unit 12 travels straight. In addition, the λ / 2 phase plate 14 may be provided not between the second light source unit 12 and the polarization beam splitter 15 but between the first light source unit 11 and the polarization beam splitter 15. In this case, the λ / 2 phase plate 14 converts the p-polarized light from the first light source unit 11 into s-polarized light. As described above, by appropriately arranging the λ / 2 phase plate 14, it is possible to supply the laser light in conformity with the transmission and reflection characteristics of the polarization beam splitter 15. Furthermore, the first light source unit 11 and the second light source unit 12 may be configured to supply s-polarized light instead of p-polarized light.

  The 1st light source part 11 and the 2nd light source part 12 should just be the structure which supplies a several laser beam, and are not restricted to the structure which supplies four laser beams. The first light source unit 11 and the second light source unit 12 are not limited to surface emitting semiconductor lasers, and a plurality of end surface emitting semiconductor lasers may be arranged in parallel. In this case, only laser light from some semiconductor lasers may be incident on the λ / 2 phase plate 14 in accordance with the polarization characteristics of each semiconductor laser.

  The light source device is not limited to the configuration using the polarization beam splitter 15 that is a prism body. As in the light source device 30 shown in FIG. 3, a plate-like polarization beam splitter 35 may be used. The polarizing beam splitter 35 is configured by bonding the polarizing film 16 to a substrate made of a transparent glass member. Even when the plate-shaped polarization beam splitter 35 is used, the laser beams from the two light source units 11 and 12 can be combined. As the polarized light combining unit, a wire grid type polarizing plate may be used instead of the polarizing beam splitter 35 including the polarizing film 16.

  Further, the light source device is not limited to the configuration in which the laser light from the first light source unit 11 and the laser light from the second light source unit 12 are emitted in a substantially coincident manner. As in the light source device 40 shown in FIG. 4, the laser light from the first light source unit 11 and the second light source unit 12 may be superposed so as to be substantially parallel and alternately arranged in parallel. The light source device 40 is obtained by shifting the positions of the first light source unit 11 and the second light source unit 12 with respect to the polarization beam splitter 15 as compared with the light source device 10 shown in FIG.

  As shown in FIG. 5, the light source device 40 has a spot SP <b> 1 due to the laser light from the first light source unit 11 and a spot SP <b> 2 due to the laser light from the second light source unit 12 alternately arranged in parallel on the irradiated surface I. Let it form. In the case of the light source device 40 as well, it is possible to supply the laser light without greatly changing the width in which the laser lights are arranged in parallel with the case of using a single light source unit. In addition, by adjusting the positions of the first light source unit 11 and the second light source unit 12 as appropriate, the laser light from the first light source unit 11 and the laser light from the second light source unit 12 are arranged at substantially equal intervals. Can be emitted.

  FIG. 6 shows a schematic configuration of the light source device 60 according to the first modification of the present embodiment. This modification includes a first light source unit 61 that supplies p-polarized light that is polarized light in the first vibration direction, and a second light source unit 62 that supplies s-polarized light that is polarized light in the second vibration direction. It is characterized by having. The first light source unit 61 and the second light source unit 62 are configured by paralleling laser elements 63 and 64 that are a plurality of edge-emitting semiconductor lasers, respectively.

  FIG. 7 illustrates the arrangement of the laser elements 63 and 64. The laser element 63 of the first light source unit 61 is arranged so that the active layer 71 is substantially horizontal. The laser element 63 in which the active layer 71 is disposed so as to be substantially horizontal supplies p-polarized light having a vibration direction in the horizontal direction. On the other hand, the laser element 64 of the second light source unit 62 is arranged so that the active layer 71 is substantially vertical. The laser element 64 in which the active layer 71 is arranged to be substantially vertical supplies s-polarized light having a vibration direction in the vertical direction. The lens 72 provided on the emission side of the laser elements 63 and 64 shapes the laser beam supplied from the active layer 71 and emits it.

  In the light source device 60, it is not necessary to provide a phase plate between the first light source unit 61 and the polarizing beam splitter 15 and between the second light source unit 62 and the polarizing beam splitter 15. Therefore, the laser light from the first light source unit 61 and the laser light from the second light source unit 62 can be combined with a simple configuration without using a phase plate. The first light source unit 61 and the second light source unit 62 may be configured to supply polarized light whose vibration directions are orthogonal to each other. For example, the first light source unit 61 uses the s-polarized light and the second light source unit 62 uses the s-polarized light. It may be configured to supply p-polarized light.

  FIG. 8 shows a schematic configuration of a light source device 80 according to the second modification of the present embodiment. The light source device 80 of this modification is characterized by emitting a plurality of color lights substantially in parallel. The light source device 80 is a first light source unit 11R for R light and a second light source unit 12R for R light that supply red laser light (hereinafter referred to as “R light”) that is first color light, and second color light. The first light source unit 11G for G light and the second light source unit 12G for G light that supply green laser light (hereinafter referred to as “G light”) are provided. The light source device 80 has the same configuration as that of the light source device 10 described above for R light and G light.

  The R light from the R light first light source unit 11R and the R light second light source unit 12R is combined by the R light polarizing beam splitter 15R. The R light polarization beam splitter 15R is a first polarized light combining unit that combines R light that is first color light. The G light from the G light first light source unit 11G and the G light second light source unit 12G is combined by the G light polarizing beam splitter 15G. The G light polarization beam splitter 15G is a second polarized light combining unit that combines the G light that is the second color light. In the R light polarizing beam splitter 15R and the G light polarizing beam splitter 15G, the emission direction of the R light from the R light polarization beam splitter 15R and the emission direction of the G light from the G light polarization beam splitter 15G are substantially orthogonal. Are arranged to be.

  A dichroic mirror 88 is provided at a position where the R light from the R light polarizing beam splitter 15R and the G light from the G light polarizing beam splitter 15G are incident. The dichroic mirror 88 emits the R light from the R light polarizing beam splitter 15R, which is the first polarized light combining unit, and the G light from the G light polarizing beam splitter 15G, which is the second polarized light combining unit, in a substantially parallel manner. This is a color composition unit to be synthesized. The dichroic mirror 88 is configured by bonding a dichroic film 89 to a substrate made of a transparent glass member. As the dichroic film 89, for example, a dielectric multilayer film can be used. Instead of the dichroic mirror 88, a dichroic prism may be used.

  The dichroic film 89 transmits R light and reflects G light. The dichroic mirror 88 is arranged such that the dichroic film 89 is inclined by approximately 45 degrees with respect to both the R light exit direction from the R light polarization beam splitter 15R and the G light exit direction from the G light polarization beam splitter 15G. Is arranged. The R light from the R beam polarizing beam splitter 15R passes through the dichroic mirror 88 and proceeds as it is in the emission direction. The G light from the G light polarizing beam splitter 15G is reflected by the dichroic film 89, whereby the optical path is bent by approximately 90 degrees. The G light reflected by the dichroic film 89 travels in the same emission direction as the R light transmitted through the dichroic film 89. With this configuration, it is possible to emit the four R light and the four G light so that they substantially coincide with each other. In this way, color lights having different wavelength regions can be combined using the dichroic mirror 88.

  The light source device 80 is not limited to the configuration using the light source units 11R and 12R that supply R light and the light source units 11G and 12G that supply G light, and supplies blue laser light (hereinafter referred to as “B light”). It is also possible to employ a configuration using a light source unit. In addition, a configuration for supplying B light similar to that of the light source device 10 may be added to the configuration of the light source device 80. In this case, the laser beams for the three primary colors can be emitted substantially in the same manner.

  FIG. 9 shows a schematic configuration of an optical scanning device 90 according to the second embodiment of the present invention. The optical scanning device 90 includes the light source device 10 described above. The same parts as those of the light source device 10 of the first embodiment are denoted by the same reference numerals, and redundant description is omitted. A convex lens 91 and a concave lens 92 provided on the emission side of the light source device 10 are an illumination optical system 95 provided between the light source device 10 and the scanning unit 93. The illumination optical system 95 supplies the four laser beams to the scanning unit 93 with the converging action of the convex lens 91 and the diffusing action of the concave lens 92 being substantially parallel and having a smaller interval than when emitted from the light source device 10. The scanning unit 93 scans the laser light from the light source device 10.

  FIG. 10 shows a schematic configuration of the scanning unit 93. The scanning unit 93 has a so-called double gimbal structure including a reflection mirror 202 and an outer frame portion 204 provided around the reflection mirror 202. The outer frame portion 204 is connected to a fixed portion (not shown) by a torsion spring 206 that is a rotating shaft. The outer frame portion 204 rotates around the torsion spring 206 using the twist of the torsion spring 206 and the restoration to the original state. The reflection mirror 202 is connected to the outer frame portion 204 by a torsion spring 207 that is a rotation axis substantially orthogonal to the torsion spring 206. The reflection mirror 202 reflects the laser light from the light source device 10. The reflection mirror 202 can be configured by forming a highly reflective member, for example, a metal thin film such as aluminum or silver.

  The reflection mirror 202 is displaced so as to scan the laser beam in the vertical direction on the irradiated surface by rotating the outer frame portion 204 around the torsion spring 206. The reflection mirror 202 rotates about the torsion spring 207 using the twist of the torsion spring 207 and the restoration to the original state. The reflection mirror 202 is displaced so as to scan the laser beam reflected by the reflection mirror 202 in the horizontal direction by rotating about the torsion spring 207. In this way, the scanning unit 93 scans the laser light from the light source device 10 in the two-dimensional direction.

  FIG. 11 illustrates a configuration for driving the scanning unit 93. Assuming that the side on which the reflection mirror 202 reflects the laser light is the front side, the first electrodes 301 and 302 are spaces on the back side of the outer frame portion 204 and are provided at substantially symmetrical positions with respect to the torsion spring 206. Yes. When a voltage is applied to the first electrodes 301 and 302, a predetermined force corresponding to the potential difference, for example, an electrostatic force, is generated between the first electrodes 301 and 302 and the outer frame portion 204. The outer frame portion 204 rotates about the torsion spring 206 by alternately applying a voltage to the first electrodes 301 and 302.

  Specifically, the torsion spring 207 includes a first torsion spring 307 and a second torsion spring 308. A mirror-side electrode 305 is provided between the first torsion spring 307 and the second torsion spring 308. A second electrode 306 is provided in the space behind the mirror side electrode 305. When a voltage is applied to the second electrode 306, a predetermined force according to the potential difference, for example, an electrostatic force, is generated between the second electrode 306 and the mirror side electrode 305. When a voltage having the same phase is applied to any of the second electrodes 306, the reflection mirror 202 rotates about the torsion spring 207. The scanning unit 93 rotates the reflection mirror 202 in this way, thereby scanning the laser light in the two-dimensional direction. The scanning unit 93 can be created by, for example, MEMS (Micro Electro Mechanical Systems) technology.

  In addition, the scanning part 93 is not restricted to the structure driven with the electrostatic force according to an electrical potential difference. For example, the structure driven using the expansion-contraction force or electromagnetic force of a piezoelectric element may be sufficient. The scanning unit 93 may include a reflection mirror that scans the laser beam in the horizontal direction and a reflection mirror that scans the laser beam in the vertical direction. Furthermore, the scanning unit 93 is not limited to a configuration using a galvanometer mirror, and may be a configuration using a polygon mirror that rotates a rotating body having a plurality of mirror pieces.

  By using the light source device 10 described above, the laser light synthesized by the light source device 10 can be scanned. In addition, since the width in which the laser beams are arranged in parallel can be made substantially the same as the case where a single light source unit is used, a small scanning unit 93 can be used. Thereby, the laser beam synthesized by the light source device 10 can be scanned stably and at high speed. When laser light from a plurality of light source units is scanned, a configuration in which laser light is scanned by a plurality of scanning units provided for each light source unit is also conceivable. On the other hand, in the case of the present embodiment, since the scanning unit 93 can be made small and a single scanning unit 93 can be used, the optical system can also have a simple configuration. Further, by using the illumination optical system 95, the laser light synthesized by the light source device 10 can be scanned at a desired interval.

  The illumination optical system 95 is not limited to the configuration using the convex lens 91 and the concave lens 92 as long as the four laser beams can be made substantially parallel and the interval can be reduced. Further, the illumination optical system 95 may be configured to emit a plurality of laser beams substantially parallel and at intervals different from those emitted from the light source device 10, and may be configured to increase the interval of the laser beams.

  FIG. 12 shows a schematic configuration of an optical scanning device 120 according to a modification of the present embodiment. The optical scanning device 120 of this modification has an illumination optical system 121 that condenses a plurality of laser beams. As the illumination optical system 121, a convex lens having a convergence function can be used. By condensing a plurality of laser beams by the illumination optical system 121, the scanning unit 93 can be further reduced in size. Further, laser light can be scanned at a desired interval on the irradiated surface. In this modification, the illumination optical system 121 is configured to form a focal point on the reflection mirror 202 (see FIG. 10) of the scanning unit 93. In addition, the illumination optical system 121 may be configured to form a focal point before or after incidence of the reflection mirror 202 as long as each laser beam can be incident on the reflection mirror 202.

  The optical scanning device according to the present embodiment may be configured to combine the laser beams after the intervals between the plurality of laser beams are changed by the illumination optical system. However, when the interval between the laser beams is made small, it is easier to combine the plurality of laser beams by using a configuration in which the plurality of laser beams are combined and then incident on the illumination optical system as described in this embodiment. Is possible. Further, when an illumination optical system is provided between the light source unit and the polarization beam splitter, it is necessary to use as many illumination optical systems as the number of the light source units. On the other hand, when the configuration is such that the light from the polarization beam splitter is incident on the illumination optical system, there is also an advantage that a single configuration can be provided for the illumination optical system.

  Further, as a configuration for condensing a plurality of laser beams, a configuration in which no illumination optical system is used, such as an optical scanning device 150 shown in FIG. 14, is possible. The light source device 145 of the optical scanning device 150 condenses the laser light from the first light source unit 141 and the laser light from the second light source unit 142 on the scanning unit 93. The laser element 143 of the first light source unit 141 is disposed so as to focus the laser beam on the scanning unit 93 after passing through the polarization beam splitter 15. The laser element 143 of the second light source unit 142 is arranged so as to focus the laser beam on the scanning unit 93 after being reflected by the polarizing film 16 of the polarization beam splitter 15. In this manner, the polarization beam splitter 15 that is a polarized light combining unit may be configured to combine the laser light from the first light source unit 141 and the laser light from the second light source unit 142 so as to be condensed.

  FIG. 13 shows a schematic configuration of an image display apparatus 130 according to the third embodiment of the present invention. The image display device 130 includes the optical scanning device 90 described above. The image display device 130 is a so-called rear projector that supplies laser light to one surface of the screen 140 and observes an image by observing light emitted from the other surface of the screen 140. The image display device 130 displays an image by scanning a laser beam modulated according to an image signal.

  The optical scanning device 90 scans the irradiated surface of the screen 140 in the horizontal X direction and the vertical Y direction. In the figure, the optical scanning device 90 is configured to scan a single color light, but is configured to scan R light, G light, and B light modulated according to an image signal. The optical scanning device 90 may be configured to include three light source devices for each color light, and may be configured to include a light source device that supplies the plurality of color lights described with reference to FIG.

  The laser light from the optical scanning device 90 enters the reflection unit 135 after passing through the projection optical system 133. The projection optical system 133 forms an image of the laser light from the optical scanning device 90 on the screen 140. The reflection unit 135 reflects the laser beam from the optical scanning device 90 toward the screen 140. The housing 137 seals the space inside the housing 137. The screen 140 is provided on a predetermined surface of the housing 137. The screen 140 is a transmissive screen that transmits laser light modulated in accordance with an image signal. The light from the reflection unit 135 enters the screen 140 from the surface on the inner side of the housing 137 and then exits from the surface on the viewer side. The observer observes the image by observing the light emitted from the screen 140.

  The scanning unit 93 of the optical scanning device 90 reciprocates the laser light a plurality of times in the X direction which is the horizontal direction while scanning the laser light once in the Y direction which is the vertical direction in one frame period of the image, for example. Then, the reflecting mirror 202 (see FIG. 10) is displaced. In order to scan the laser beam in the X direction at high speed, the scanning unit 93 preferably has a configuration in which the reflection mirror 202 is resonated around the torsion spring 207 (see FIG. 10). By resonating the reflection mirror 202, the amount of displacement of the reflection mirror 202 can be increased. By increasing the amount of displacement of the reflection mirror 202, the scanning unit 93 can efficiently scan the laser beam with less energy. Note that the reflection mirror 202 may be driven without using resonance.

  The image display apparatus 130 scans four laser beams for each color light every four rows. In this way, by paralleling a plurality of laser beams for each color light, scanning in the irradiated region can be shared by the plurality of laser beams. When scanning is shared by a plurality of laser beams, it is possible to display an image at a lower modulation frequency than when scanning a single laser beam.

  The image display device 130 can scan the laser light synthesized by the light source device 10 stably and at high speed by using the optical scanning device 90 described above. Thereby, a bright and high-quality image can be displayed. The optical scanning device 90 may be used for a so-called front projection type projector. A front projection type projector is an image display device that appreciates an image by supplying laser light to a screen provided on an observer side and observing light reflected by the screen.

  As described above, the light source device according to the present invention is suitable for use in an image display device that displays an image by scanning a light beam modulated in accordance with an image signal.

The figure which shows schematic structure of the light source device which concerns on Example 1 of this invention. The figure which shows the spot formed in a to-be-irradiated surface. The figure which shows the structure using a plate-shaped polarizing beam splitter. The figure which shows the structure which arranges a laser beam in parallel substantially and alternately. The figure which shows the spot formed in a to-be-irradiated surface. FIG. 6 is a diagram illustrating a schematic configuration of a light source device according to a first modification of the first embodiment. The figure explaining arrangement | positioning of a laser element. FIG. 6 is a diagram illustrating a schematic configuration of a light source device according to a second modification of the first embodiment. FIG. 5 is a diagram illustrating a schematic configuration of an optical scanning device according to a second embodiment of the invention. The figure which shows schematic structure of a scanning part. The figure explaining the structure for driving a scanning part. FIG. 10 is a diagram illustrating a schematic configuration of an optical scanning device according to a modification of the second embodiment. FIG. 9 is a diagram illustrating a schematic configuration of an image display device according to a third embodiment of the invention. The figure which shows schematic structure of the other optical scanning device which condenses a some laser beam.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Light source device, 11 1st light source part, 12 2nd light source part, 14 (lambda) / 2 phase plate, 15 polarizing beam splitter, 16 polarizing film, I irradiation surface, SP spot, 30 light source device, 35 polarizing beam splitter, 40 Light source device, SP1, SP2 spot, 60 light source device, 61 first light source unit, 62 second light source unit, 63, 64 laser element, 71 active layer, 72 lens, 80 light source device, first light source unit for 11RR light, 11G G light first light source unit, 12R R light second light source unit, 12G G light second light source unit, 15R R light polarizing beam splitter, 15G G light polarizing beam splitter, 88 dichroic mirror, 89 dichroic film , 90 optical scanning device, 91 convex lens, 92 concave lens, 93 scanning unit, 95 illumination optical system, 202 reflecting mirror, 204 outside Frame portion, 206 torsion spring, 207 torsion spring, 301, 302 first electrode, 305 mirror side electrode, 306 second electrode, 307 first torsion spring, 308 second torsion spring, 120 optical scanning device, 121 Illumination optical system, 130 image display device, 133 projection optical system, 135 reflection unit, 137 casing, 140 screen, 141 first light source unit, 142 second light source unit, 143 laser element, 150 optical scanning device

Claims (14)

A first light source unit and a second light source unit that supply a plurality of light beams that are linearly polarized light of the same color;
A light source device comprising: a polarized light combining unit configured to combine the beam light from the first light source unit and the beam light from the second light source unit.   2. The light source device according to claim 1, wherein the polarized light combining unit combines the beam light from the first light source unit and the beam light from the second light source unit so as to emit substantially in parallel. .   2. The light source device according to claim 1, wherein the polarized light combining unit combines the beam light from the first light source unit and the beam light from the second light source unit so as to be condensed.   The polarized light combining unit transmits the polarized light in the first vibration direction and reflects the polarized light in the second vibration direction substantially orthogonal to the first vibration direction to combine the beam light. The light source device according to claim 1. The first light source unit and the second light source unit are arranged so that the optical axis of the first light source unit and the optical axis of the second light source unit are substantially orthogonal,
The polarized light combining unit includes a polarizing film that transmits polarized light in the first vibration direction and reflects polarized light in the second vibration direction, and the polarizing film includes an optical axis of the first light source unit and The light source device according to claim 4, wherein the light source device is disposed so as to be inclined at approximately 45 degrees with respect to any of the optical axes of the second light source unit.   The phase plate is provided between the first light source unit and the polarized light combining unit or between the second light source unit and the polarized light combining unit. The light source device according to item. The first light source unit supplies the beam light that is polarized light in the first vibration direction,
The light source device according to claim 1, wherein the second light source unit supplies the beam light that is polarized light in the second vibration direction.   The polarized light combining unit synthesizes the light beam of the beam light from the first light source unit and the light beam of the beam light from the second light source unit so as to substantially coincide with each other. The light source device according to any one of the above.   The polarized light combining unit synthesizes the beam of light from the first light source unit and the beam of light from the second light source unit alternately in parallel. 8. The light source device according to any one of 7. A first polarized light combining unit that combines the first color light; a second polarized light combining unit that combines the second color light;
10. A color synthesis unit that synthesizes the first color light from the first polarized light synthesis unit and the second color light from the second polarized light synthesis unit. 10. The light source device according to 1. The light source device according to any one of claims 1 to 10,
And a scanning unit that scans the light from the light source device. An illumination optical system provided between the light source device and the scanning unit;
The optical scanning device according to claim 11, wherein the illumination optical system emits the plurality of light beams substantially in parallel and at intervals different from those emitted from the light source device. An illumination optical system provided between the light source device and the scanning unit;
The optical scanning apparatus according to claim 11, wherein the illumination optical system condenses a plurality of the light beams. An image display device that displays an image by light from an optical scanning device,
The image scanning device according to claim 11, wherein the optical scanning device is an optical scanning device according to claim 11.

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