JP6380471B2 - Three color light source - Google Patents

Description

  The present invention relates to a three-color light source used for a display, illumination, communication, analysis, medical equipment, or the like.

  Patent Document 1 describes a laser projection device that is a projection display that projects an image on a screen. The laser projection device includes a red laser light source, a blue laser light source, a green laser light source, and a heat radiating unit. The heat radiating unit emits heat in the housing of the laser projection device to the outside by outputting cooling water into the housing. The cooling water output from the heat radiating part cools the red laser light source, then takes heat from the blue laser light source and the green laser light source, and returns to the heat radiating part. In this manner, the red laser light source is preferentially dissipated by the cooling water over the blue laser light source and the green laser light source, so that the temperature of the red laser light source is kept low.

  Patent Document 2 describes a multiple laser coaxial light source device. The multiple laser coaxial light source device includes a collimator lens, a semiconductor laser array having three light emitting points, pulse lighting control means for selectively lighting the light emitting points, and a relative position between the collimator lens and the semiconductor laser array. Relative position control means for changing The relative position control means adjusts the relative position between the collimator lens and the semiconductor laser array so that the optical axis of the collimator lens is positioned on the optical axis of each laser beam emitted by the pulse lighting in accordance with the pulse lighting timing. To control. Each laser beam is converted into parallel light by the collimator lens, and each laser beam is quasi-coaxially formed in the overlapping portion of the passing regions of the laser beams.

  Patent Document 3 describes a planar illumination device. This planar illumination device includes a laser light source that emits laser beams of three colors having different wavelengths, a fiber that emits laser beams of three colors from one end and emits the laser light from the other end as emitted light, And a transmissive optical member that converts the emitted light into planar illumination light. The plurality of laser beams have different NAs according to different wavelengths and enter one end of the fiber.

International Publication No. 2007/040089 JP 2011-165715 A JP 2009-266463 A

  In the three-color light source as described above, when a white light source is configured by mounting an LD (Laser Diode) that emits red, green, and blue laser light, chromatic dispersion appearing in the condensed light is taken into consideration. There is a need. In particular, an LD that emits red laser light has a large temperature coefficient of the wavelength of the emitted light, and the wavelength is likely to fluctuate due to changes in the ambient environmental temperature. That is, the red laser light has a larger temperature characteristic than the green laser light and the blue laser light. For example, when an LD that emits red laser light using an AlGaInP-based material is configured, the wavelength is 10 nm at the longest and the light output (luminous efficiency) changes by about 40% in the range of the environmental temperature of 20 ° C. to 70 ° C.

  In addition, the combined light of each light converted into collimated light by a collimating lens corresponding to the light emitted from each LD may be condensed via a scanning optical system (MEMS or the like). Therefore, when the collimating property of each light is not maintained in the collimating lens, color blur such as astigmatism and spherical aberration may occur when the light is condensed through the scanning optical system. Further, as described above, the red LD, in particular, has a problem that it is difficult to maintain the quality because the temperature characteristic is greatly influenced and the refractive index of the lens and the focal position of the lens are liable to change depending on the temperature.

  It is an object of the present invention to provide a three-color light source that is less susceptible to environmental temperature and can maintain collimating properties.

  A three-color light source according to an aspect of the present invention is a three-color light source that combines and outputs red, green, and blue laser beams, and is configured by a GaAs-based material that emits a first laser beam. And a second laser diode composed of a GaN-based material that emits a second laser light, and a third laser light composed of a GaN-based material and having a wavelength different from that of the second laser light. A third laser diode; a first collimating lens that collimates the first laser light; a second collimating lens that collimates the second laser light; and a third collimating lens that collimates the third laser light. And transmitting the first laser light collimated by the first collimating lens and reflecting the second laser light collimated by the second collimating lens, A first wavelength filter that outputs a first combined light obtained by combining the light and the second laser light, and transmits or reflects one of the first combined light and collimates by a third collimating lens. A second wavelength filter that outputs the second combined light obtained by combining the first combined light and the third laser light by performing the other one of transmission and reflection on the third laser light thus generated; A carrier on which first to third laser diodes, first to third collimating lenses and first and second wavelength filters are mounted, and a temperature control element on which the carrier is mounted.

  According to the present invention, it is possible to provide a three-color light source that is less susceptible to environmental temperature and can maintain collimating properties.

FIG. 1 is a perspective view showing a three-color light source according to the first embodiment of the present invention. FIG. 2 is a perspective view showing a state in which the cap of the three-color light source shown in FIG. 1 is removed. FIG. 3 is a graph showing the relationship between the wavelength of the laser beam and the light receiving sensitivity . FIG. 4A is a perspective view showing the carrier and the intermediate assembly, and FIG. FIG. 3 is a perspective view showing a TEC and a base member. FIG. 5 is a perspective view showing a state where the carrier is mounted on the TEC. In FIG. 6, each component on the base member and each lead pin are wired. It is a perspective view which shows a state. 7 is a perspective view showing a state in which a collimating lens is mounted on the carrier of FIG. It is. FIG. 8 is a perspective view showing a state in which a wavelength filter is mounted on the carrier of FIG. FIG. 9 is a chart showing the beam pattern of each color . FIG. 10 is a perspective view showing a three-color light source according to the second embodiment of the present invention. FIG. 11 is a perspective view showing a state in which the cap of the three-color light source shown in FIG. 10 is removed.

  Hereinafter, embodiments of a three-color light source according to the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
FIG. 1 is a perspective view showing a three-color light source 1 according to the first embodiment of the present invention. FIG. 2 is a perspective view showing a state in which the cap 2 is removed from the three-color light source 1. As shown in FIG. 1 and FIG. 2, the three-color light source 1 generates a first combined light L1 obtained by combining the red laser light LR and the green laser light LG, and the first combined light L1 and the blue laser light. A second combined light L2 obtained by combining LB is generated. The three-color light source 1 includes a red LD 11, a green LD 12, a blue LD 13, a first submount 21, a second submount 22, a third submount 23, a carrier 30, a TEC (temperature control element) 40, and a base member 50. , A mirror 91, a PD (photodiode) 92, and a thermistor (temperature measuring resistor) 93.

  In the following, the terms “vertical direction”, “front-rear direction”, and “left-right direction” are used in the drawings, but these terms are for convenience based on the illustrated state. In the following description, the upward direction is the normal direction of the carrier 30 (the emission direction of the combined light L2), the forward direction is the emission direction of the red laser light LR from the red LD 11, and the right direction is the green color from the green LD 12. This is the emission direction of the laser beam LG (the emission direction of the blue laser beam LB from the blue LD 13).

  The base member 50 has a flat main surface 50a. Eighteen lead pins 51 are passed through the base member 50. Of the 18 lead pins 51, nine lead pins 51 are arranged in the front-rear direction on the left side of the TEC 40, and the remaining nine lead pins 51 are arranged in the front-rear direction on the right side of the TEC 40. Each lead pin 51 protrudes on the main surface 50 a of the base member 50.

  In addition, eight 18 lead pins 51 are assigned for signals supplied to the anode and the cathode of each of the LDs 11 to 13 and PD 92, and two for supplying current to the TEC 40, and the other lead pins 51 are assigned. Are assigned as GND lines. Instead of the base member 50, for example, a general-purpose coaxial package having an outer diameter of 5.6 mm, a square ceramic package, or a bare substrate (hybrid IC substrate) such as AlN, SiC, or sapphire can be used.

  The TEC 40 is mounted on the main surface 50 a of the base member 50. The wiring pads of the TEC 40 are electrically connected to the lead pins 51 through the bonding wires B8. A carrier 30 is mounted on the TEC 40. The wiring pads of the carrier 30 are electrically connected to the lead pins 51 through bonding wires B7. The carrier 30 has a first main surface 30a and a second main surface 30b. The second main surface 30b is formed by cutting out the front side and the right side of the first main surface 30a from above, and the height of the second main surface 30b is higher than the height of the first main surface 30a. It is low.

  That is, the carrier 30 has a first main surface 30a and a second main surface 30b having different heights, and a step is formed by these main surfaces 30a and 30b. Further, the shape of the carrier 30 in plan view is, for example, a square shape having a side of about 10 mm. In plan view, the first main surface 30a is formed in an L shape. The first main surface 30a is an LD mounting area on which the red LD 11, the green LD 12, and the blue LD 13 are mounted. The first to third submounts 21, 22, and 23 also have flat main surfaces 21a, 22a, and 23a, respectively.

  The red LD 11 is the first laser diode in the present embodiment, and emits red laser light (first laser light) LR. The red LD 11 is a red semiconductor laser made of, for example, a GaAs material. Here, the GaAs-based material refers to a semiconductor material lattice-matched to GaAs, and includes, for example, GaAs, AlGaInP, and the like. The red LD 11 is mounted on the main surface 21 a of the first submount 21, and is mounted on the first main surface 30 a of the carrier 30 via the first submount 21. The red LD 11 is electrically connected to the first submount 21 via the bonding wire B1, and the first submount 21 is electrically connected to the lead pin 51 via the bonding wire B2. The red LD 11 emits red laser light LR with an optical axis along the first main surface 30a. The wavelength of the red laser light LR emitted from the red LD 11 is, for example, 640 nm.

  The green LD 12 is the second laser diode in the present embodiment, and emits green laser light (second laser light) LG. The green LD 12 is mounted on the main surface 22 a of the second submount 22, and is mounted on the first main surface 30 a of the carrier 30 via the second submount 22. The green LD 12 is electrically connected to the second submount 22 via the bonding wire B3, and the second submount 22 is electrically connected to the lead pin 51 via the bonding wire B4. The green LD 12 emits the green laser light LG along the optical axis along the first main surface 30a. In the present embodiment, the emission direction of the green laser light LG from the green LD 12 is perpendicular to the emission direction of the red laser light LR from the red LD 11. The wavelength of the green laser beam LG is, for example, 535 nm. The green LD 12 is made of, for example, a GaN-based material. Typically, GaN itself is applicable, but not limited thereto. Any material that can output green light having a wavelength of about 500 to 550 nm may be used.

  The blue LD 13 is the third laser diode in the present embodiment, and emits blue laser light (third laser light) LB. The blue LD 13 is mounted on the main surface 23 a of the third submount 23, and is mounted on the first main surface 30 a of the carrier 30 via the third submount 23. The blue LD 13 is electrically connected to the third submount 23 via the bonding wire B5, and the third submount 23 is electrically connected to the lead pin 51 via the bonding wire B6. The blue LD 13 emits the blue laser light LB along the optical axis along the first main surface 30a. In the present embodiment, the emission direction of the blue laser light LB from the blue LD 13 is perpendicular to the emission direction of the red laser light LR from the red LD 11, and the emission direction of the green laser light LG from the green LD 12. Is parallel to. The wavelength of the blue laser beam LB is, for example, 440 nm. The blue LD 13 is made of a GaN-based material, for example. Typically, GaN itself is applicable, but not limited thereto. Any material that can output blue light having a wavelength of about 410 to 460 nm may be used.

  In the present embodiment, the height of the laser light emission point of the red LD 11, the height of the laser light emission point of the green LD 12, and the laser light emission of the blue LD 13 when the first main surface 30 a of the carrier 30 is used as a reference. The heights of the submounts 21 to 23 are set so that the heights of the points are equal to each other. That is, the optical axis of the red laser light LR, the optical axis of the green laser light LG, and the optical axis of the blue laser light LB are substantially at the same height with respect to the first main surface 30a. In addition, the height of the light emission end face of each laser beam LR, LG, LB in each LD 11-13 is substantially the same as the height of the upper end of each LD 11-13.

  As a material of the first to third submounts 21 to 23, a material having a thermal expansion coefficient close to that of the semiconductor material constituting the red LD 11, the green LD 12, and the blue LD 13 can be used, for example, AlN, SiC, Si, or diamond. Etc. can be used. Each of the red LD 11, the green LD 12, and the blue LD 13 is fixed to each of the first to third submounts 21 to 23 by, for example, Au, Sn, SnAgCu, or Ag paste.

  The three-color light source 1 further includes a first collimating lens 61, a second collimating lens 62, a third collimating lens 63, a first sub-base member 71, a second sub-base member 72, and a third sub-base. A member 73, a first wavelength filter 81, a second wavelength filter 82, a fourth sub-base member 74, and a fifth sub-base member 75 are provided. The second main surface 30b of the carrier 30 is a lens mounting area on which the first collimating lens 61, the second collimating lens 62, and the third collimating lens 63 are mounted. The thickness of the first to fifth sub-base members 71 to 75 is, for example, about 0.1 mm.

  The first collimating lens 61 is optically coupled to the light emitting end face of the red LD 11 and collimates (collimates) the red laser light LR emitted from the red LD 11. The first collimating lens 61 is mounted on the first sub-base member 71, and is mounted on the second main surface 30 b of the carrier 30 via the first sub-base member 71.

  The second collimating lens 62 is optically coupled to the light emitting end face of the green LD 12 and collimates the green laser light LG emitted from the green LD 12. The second collimating lens 62 is mounted on the second sub-base member 72, and is mounted on the second main surface 30 b of the carrier 30 via the second sub-base member 72.

  The third collimating lens 63 is optically coupled to the light emitting end face of the blue LD 13 and collimates the blue laser light LB emitted from the blue LD 13. The third collimating lens 63 is mounted on a third sub-base member 73 arranged side by side (front) of the second sub-base member 72. The third collimating lens 63 is mounted on the second main surface 30 b of the carrier 30 via the third sub-base member 73.

  The optical axes of the first to third collimating lenses 61 to 63 and the optical axes of the LDs 11 to 13 are adjusted so as to substantially coincide with each other. As an example, the thickness of each of the first to third submounts 21 to 23 is 0.15 mm, and the height of the laser beam emission point of each of the LDs 11 to 13 with respect to the main surfaces 21a to 23a of each of the submounts 21 to 23 is. Is 0.1 mm, and the height of the laser beam emission point with respect to the first main surface 30a is 0.25 mm.

  Here, the first to third collimating lenses 61 to 63 are, for example, lenses that are held by a side-view square lens holder having a side of 1.0 mm, and the lens is arranged from one side of the lens holder in the side view. When the distance to the center is 0.5 mm and the height of the step between the first main surface 30a and the second main surface 30b is about 0.25 mm, the optical axis height of the LDs 11 to 13 and the collimating lens 61 The optical axis heights of ~ 63 are approximately the same.

  Further, the height of the step between the first main surface 30a and the second main surface 30b in the carrier 30 is the alignment cost in the vertical direction when the collimating lenses 61 to 63 are aligned, and the collimating lenses 61 to 63. In consideration of the coating thickness of the ultraviolet curable resin for fixing each lens holder on the second main surface 30b, it is desirable that the lens holder be made higher by several hundred μm than 0.25 mm. Therefore, for example, the thickness of the carrier 30 itself (the thickness of the LD mounting region of the carrier 30) is 1.0 mm, and the thickness of the second main surface 30b of the carrier 30 (the thickness of the lens mounting region of the carrier 30) is The height of the step between the first main surface 30a and the second main surface 30b is 0.6 mm.

  The first wavelength filter 81 is a multilayer filter formed on, for example, a glass substrate, and is mounted on the second main surface 30 b of the carrier 30 via a fourth sub-base member 74. One surface of the first wavelength filter 81 is optically coupled to the first collimating lens 61, and the other surface of the first wavelength filter 81 is optically coupled to the second collimating lens 62. Yes. The first wavelength filter 81 transmits the red laser light LR collimated by the first collimating lens 61 and reflects the green laser light LG collimated by the second collimating lens 62 forward. The optical axis of the red laser light LR transmitted through the first wavelength filter 81 and the optical axis of the green laser light LG reflected by the first wavelength filter 81 are adjusted so as to substantially coincide with each other. Thus, the first wavelength filter 81 outputs the combined light L1 obtained by combining the red laser light LR and the green laser light LG.

  Similar to the first wavelength filter 81, the second wavelength filter 82 is a multilayer filter formed on, for example, a glass substrate, and the fifth sub-base member 75 is provided on the second main surface 30b of the carrier 30. Is mounted via. One surface of the second wavelength filter 82 is optically coupled to the other surface of the first wavelength filter 81, and the other surface of the second wavelength filter 82 is optically coupled to the third collimating lens 63. Combined.

  The second wavelength filter 82 transmits the red laser light LR and the green laser light LG (combined light L1) emitted from the first wavelength filter 81 and is collimated by the third collimating lens 63 to the blue laser light LB. Reflect forward. The optical axes of the red laser light LR and the green laser light LG transmitted through the second wavelength filter 82 and the optical axis of the blue laser light LB reflected by the second wavelength filter 82 are adjusted so as to substantially coincide with each other. The

  Note that the heights of the center positions of the first wavelength filter 81 and the second wavelength filter 82 when the second main surface 30b of the carrier 30 is used as a reference are based on the second main surface 30b. In this case, it is desirable that the height of the optical axis of each laser beam LR, LG, LB is substantially the same.

  The collimating lenses 61 to 63 and the wavelength filters 81 and 82 are fixed to the sub-base members 71 to 75, for example, with Ag paste or solder. The material of the sub-base members 71 to 75 is desirably a material having a thermal expansion coefficient close to that of the collimating lenses 61 to 63 and the wavelength filters 81 and 82, for example, glass. Further, the sub base members 71 to 75 may be made of ceramic or metal. The area of the mounting surface (upper surface) of the sub-base members 71 to 75 is an area where an amount of UV curable resin necessary for fixing the collimating lenses 61 to 63 and the wavelength filters 81 and 82 mounted thereon can be applied, for example, It is desirable to be about 0.3 to 0.5 square millimeters.

  The mirror 91 is mounted on the second main surface 30 b of the carrier 30 via the sixth sub-base member 76. The mirror 91 is disposed in front of the second wavelength filter 82. The mirror 91 reflects a part of the combined light L2 upward and transmits the remaining part forward. The mirror 91 has a right triangle shape having a slope 91a, a bottom surface 91b, and a side surface 91c in a side view. That is, the mirror 91 has a slope 91a that is inclined with respect to the direction in which the optical axis of the combined light L2 extends, and a bottom surface 91b. The inclined surface 91a forms an angle of substantially 45 degrees with respect to the second main surface 30b. The bottom surface 91 b is fixed to the carrier 30.

  The inclined surface 91a of the mirror 91 reflects the combined light L2 in a direction intersecting the second main surface 30b. For example, a translucent film is formed on the slope 91a, and the light reflectance on the slope 91a is 95%, and the light transmittance on the slope 91a is 5%. The transmitted light that passes through the inclined surface 91a is refracted in the direction approaching the second main surface 30b on the inclined surface 91a.

  The PD 92 is mounted on the second main surface 30 b of the carrier 30. The PD 92 is used for monitoring the laser beams LR, LG, and LB. The PD 92 is electrically connected to the lead pin 51 by a bonding wire B9. The PD 92 is disposed obliquely below the side surface 91 c of the mirror 91. The PD 92 can detect the intensity of the combined light L2 by receiving light refracted on the inclined surface 91a of the mirror 91.

  The PD 92 desirably has high sensitivity to each of the red laser light LR, the green laser light LG, and the blue laser light LB. FIG. 3 is a graph showing a typical example of sensitivity characteristics when a Si PD is used as the PD 92. As shown in FIG. 3, although the sensitivity of the green laser light LG (wavelength of about 535 nm) and the blue laser light LB (wavelength of about 440 nm) is lower than that of the red laser light LR (wavelength of about 640 nm), Since PD has significant sensitivity, it is possible to monitor the combined light L2 mixed with three colors.

  The thermistor 93 is arranged on the left side of the red LD 11 on the first main surface 30 a of the carrier 30. The thermistor 93 is electrically connected to the lead pin 51 by a bonding wire B10.

  In the three-color light source 1 configured as described above, red laser light LR, green laser light LG, and blue laser light LB are emitted from the red LD 11, green LD 12, and blue LD 13, respectively. These laser beams LR, LG, and LB are collimated when passing through the first collimating lens 61, the second collimating lens 62, and the third collimating lens 63, respectively. The red laser light LR and the green laser light LG are combined by the first wavelength filter 81 to output the combined light L1. The combined light L1 and the blue laser light LB are combined by the second wavelength filter 82. Then, the second combined light L2 is output. The combined light L2 composed of the red laser light LR, the green laser light LG, and the blue laser light LB is reflected in the normal direction of the second main surface 30b of the carrier 30 by the inclined surface 91a of the mirror 91, and the outside of the three-color light source 1 Is emitted.

  Next, a method for manufacturing the three-color light source 1 will be described. First, as shown in FIG. 4A, the LD11 to LD13 are mounted on the main surfaces 21a, 22a, and 23a of the submounts 21 to 23, respectively. Then, electrical conduction is ensured by wire bonding from the upper surface electrodes of the respective LD11 to LD13 to the patterns of the respective submounts 21 to 23, and intermediate assemblies C1, C2, each including the LD11 to LD13 and the respective submounts 21 to 23 are secured. C3 is generated. Then, the intermediate assemblies C1 to C3 are mounted on the first main surface 30a of the carrier 30, respectively.

  The submounts 21 to 23 are first mounted on the first main surface 30a of the carrier 30, and then the LDs 11 to 13 are mounted on the main surfaces 21a to 23a of the submounts 21 to 23, and finally by wire bonding. You may ensure the electrical continuity with submount 21-23 and LD11-13. In this case, the process temperature when the submounts 21 to 23 are mounted on the first main surface 30a is higher than the process temperature when the LDs 11 to 13 are mounted on the main surfaces 21a to 23a, and the main surfaces 21a to 23a. The process temperature when mounting LD 11 to 13 is higher than the process temperature in the wire bonding.

  As described above, by making the process temperature when mounting the submounts 21 to 23 on the first main surface 30a higher than the process temperature when mounting the LDs 11 to 13 on the main surfaces 21a to 23a, the LD11 to It is possible to avoid a situation in which the positions of the submounts 21 to 23 change when the 13 is mounted. Moreover, the situation where the position of LD11-13 changes at the time of wire bonding is avoided by making process temperature when mounting LD11-13 on main surface 21a-23a higher than the process temperature in wire bonding. Is possible.

  The TEC 40 is mounted on the main surface 50a of the base member 50 in parallel with the mounting of the submounts 21 to 23 and the LDs 11 to 13 on the carrier 30 described above. As shown in FIG. 4B, the TEC 40 has an upper plate portion 41, and the upper surface of the upper plate portion 41 is a flat main surface 41a. After mounting the TEC 40 on the main surface 50a, the carrier 30 is mounted on the main surface 41a of the upper plate portion 41.

  As shown in FIGS. 5 and 6, after the carrier 30 is mounted on the main surface 41 a of the TEC 40, the PD 92 is mounted on the second main surface 30 b of the carrier 30 and the thermistor 93 is mounted on the second surface 30 b of the carrier 30. 1 on the main surface 30a. Then, wire bonding between each lead pin 51 and the wiring pad on the carrier 30, wire bonding between each lead pin 51 and the wiring pad of the TEC 40, and wire bonding between each lead pin 51 and each of the submounts 21 to 23 are performed.

  Here, the process temperature (melting point of eutectic solder) for mounting the TEC 40 on the main surface 50 a of the base member 50 is higher than the process temperature for mounting the carrier 30 on the main surface 41 a of the TEC 40. Moreover, the process temperature in mounting the carrier 30 on the main surface 41a is higher than the process temperature in the wire bonding.

  Thus, the position of the TEC 40 is changed when the carrier 30 is mounted by making the process temperature for mounting the TEC 40 on the main surface 50a higher than the process temperature for mounting the carrier 30 on the main surface 41a. It becomes possible to avoid the situation. Further, by making the process temperature for mounting the carrier 30 on the main surface 41a higher than the process temperature for wire bonding, it is possible to avoid a situation in which the position of the carrier 30 changes when wire bonding is performed. .

  Next, mounting of the collimating lenses 61 to 63 will be described.

  As shown in FIG. 7, when the collimating lenses 61 to 63 are mounted, the collimating lenses 61 to 63 are adjusted by adjusting the positions of the collimating lenses 61 to 63 while observing the projection pattern of the emitted light from the collimating lenses 61 to 63. Perform optical alignment of ~ 63.

  When the positions of the collimating lenses 61 to 63 are adjusted, it is confirmed whether or not the light emitted from the collimating lenses 61 to 63 is collimated. Here, if the quality of the collimator is low (if collimation is not good), aberrations (astigmatism and spherical aberration) in the combined light L2 of the red laser light LR, the green laser light LG, and the blue laser light LB. May increase, for example, and may cause a problem that image quality deteriorates. Therefore, in this embodiment, the optical alignment of the three collimating lenses 61 to 63 is performed by the following procedure in order to maintain high collimating properties.

  First, the relative position between the red LD 11 and the first collimating lens 61 is determined. At this time, the first collimating lens 61 is mounted on the second main surface 30 b of the carrier 30 via the first sub-base member 71. Then, the first collimating lens 61 is fixed on the first sub-base member 71 while causing the red LD 11 to emit light. Here, the red laser light LR from the red LD 11 goes straight forward without being reflected.

  In addition, the vertical position of the first collimating lens 61 is adjusted so that the optical axis of the red laser light LR is substantially parallel to the main surfaces 30 a and 30 b of the carrier 30. At this time, for example, the upper and lower positions of the collet are adjusted while adsorbing the first collimating lens 61 with a collet or the like while applying the ultraviolet curable resin to the first sub-base member 71 and securing the thickness thereof. Thereby, the turning angle of the red laser light LR with respect to the main surfaces 30a and 30b is adjusted.

  Then, for example, an image sensor such as a CCD is disposed at a position a predetermined distance (for example, 1 to 2 m) ahead of the light emitting end face of the red LD 11, and the beam diameter of the red laser light LR projected onto the CCD is observed. While aligning the first collimating lens 61, one focal point of the first collimating lens 61 and the light emitting end face of the red LD 11 are made to coincide. Thus, by making one focal point of the first collimating lens 61 coincide with the light emitting end face of the red LD 11, the red laser light LR output from the first collimating lens 61 becomes substantially collimated light.

  When the distance between the first collimating lens 61 and the light emitting end face of the red LD 11 is shorter than the focal length of the first collimating lens 61, the red laser light LR emitted from the first collimating lens 61 is divergent. It becomes light. On the other hand, when the distance between the first collimating lens 61 and the light emitting end face is longer than the focal length, the red laser light LR emitted from the first collimating lens 61 becomes convergent light.

  However, in the present embodiment, as described above, one focal point of the first collimating lens 61 and the light emitting end surface of the red LD 11 are matched, so that the red laser light LR emitted from the first collimating lens 61 The luminous flux is substantially parallel, and the projection pattern can be observed even at a position several m away. As described above, after making one focal point of the first collimating lens 61 coincide with the light emitting end surface of the red LD 11, the ultraviolet curable resin on the first sub-base member 71 is cured to cure the first collimating lens 61. Is fixed on the first sub-base member 71.

  Next, the relative position between the green LD 12 and the second collimating lens 62 is determined. At this time, the second collimating lens 62 is mounted on the second main surface 30 b of the carrier 30 via the second sub-base member 72. Then, the second collimating lens 62 is fixed on the second sub-base member 72 while causing the green LD 12 to emit light. Here, the green laser beam LG from the green LD 12 goes straight to the right without being reflected.

  Further, the vertical position of the second collimating lens 62 is adjusted so that the optical axis of the green laser light LG is substantially parallel to the main surfaces 30a and 30b of the carrier 30. At this time, for example, the upper and lower positions of the collet are adjusted while adsorbing the second collimating lens 62 with a collet or the like while applying the ultraviolet curable resin to the second sub-base member 72 and securing the thickness thereof. Thereby, the turning angle of the green laser light LG with respect to the main surfaces 30a and 30b is adjusted.

  Then, for example, an image sensor such as a CCD is arranged at a position a predetermined distance (for example, 1 to 2 m) to the right from the light emitting end face of the green LD 12, and the beam diameter of the green laser light LG projected on the CCD is observed. However, by aligning the second collimating lens 62, one focal point of the second collimating lens 62 and the light emitting end face of the green LD 12 are matched. Thus, by making one focal point of the second collimating lens 62 coincide with the light emitting end face of the green LD 12, the green laser light LG output from the second collimating lens 62 becomes substantially collimated light.

  Instead of the above-described arrangement of the CCD or the like, an observation mirror that reflects the green laser light LG forward is disposed at a position that is a predetermined distance away from the light emitting end face of the green LD 12 and the front of the observation mirror. The above-described alignment may be performed by disposing an image sensor such as a CCD on the center.

  Subsequently, the relative position between the blue LD 13 and the third collimating lens 63 is determined. At this time, similarly to the step of determining the relative position between the green LD 12 and the second collimating lens 62, the third focal point of the third collimating lens 63 and the light emitting end face of the blue LD 13 are made to coincide with each other. The blue laser light LB output from the collimating lens 63 is set as collimated light. In each step described above, it is desirable that the optical axis of the red laser light LR, the optical axis of the green laser light LG, and the optical axis of the blue laser light LB be the same height.

  Next, as shown in FIG. 8, the first wavelength filter 81 is mounted on the second main surface 30 b of the carrier 30. At this time, the angle of the first wavelength filter 81 is adjusted so that the projection pattern of the green laser beam LG in the above-described imaging device such as a CCD substantially matches the projection pattern of the red laser beam LR. Here, as shown in FIG. 9, the projection pattern of the red laser light LR is an ellipse that is long in the X direction, and the projection patterns of the green laser light LG and the blue laser light LB are substantially circular. Therefore, as in the present embodiment, each laser beam LR is obtained by matching each projection pattern of the green laser beam LG and the blue laser beam LB with the projection pattern of the red laser beam LR with reference to the projection pattern of the red laser beam LR. , LG, LB can be easily adjusted.

  Specifically, first, the first wavelength filter 81 is placed on the optical axis of the green laser beam LG, and the first wavelength filter 81 reflects the green laser beam LG to project a projection pattern onto a projection surface such as a CCD. Let Then, by adjusting the deflection angle and the tilt angle of the first wavelength filter 81, the projection pattern of the green laser light LG is substantially matched with the projection pattern of the red laser light LR. After adjusting the deflection angle and the tilt angle of the first wavelength filter 81 to substantially match the projection pattern of the green laser light LG with the projection pattern of the red laser light LR, the fourth sub-base member 74 is moved. The first wavelength filter 81 is fixed to the fourth sub-base member 74 by curing the ultraviolet curable resin.

  Note that the projection pattern of the red laser light LR is slightly translated by the first wavelength filter 81 under the influence of the thickness of the first wavelength filter 81. However, if the projection pattern of the green laser beam LG and the blue laser beam LB is substantially matched to the projection pattern of the red laser beam LR that has been translated, alignment can be performed without any problem.

  Subsequently, the second wavelength filter 82 is mounted on the second main surface 30 b of the carrier 30. At this time, as in the case where the first wavelength filter 81 is mounted, the deflection angle and the tilt of the second wavelength filter 82 are set so that the projected pattern of the blue laser light LB substantially coincides with the projected pattern of the red laser light LR. Adjust the corners. In addition, the second wavelength filter 82 is arranged so that the light reflection surface of the first wavelength filter 81 and the light reflection surface of the second wavelength filter 82 are parallel to each other. A specific adjustment method is the same as the arrangement procedure of the first wavelength filter 81 described above.

  Next, the mirror 91 is mounted on the second main surface 30 b of the carrier 30. The mirror 91 is mounted on the second main surface 30b with the inclined surface 91a forming an angle of 45 degrees with respect to the second main surface 30b. The mirror 91 is fixed on the sixth sub-base member 76 with an ultraviolet curable resin. Thereafter, the main surface 50a of the base member 50 is covered with the cap 2, and a hermetic seal is applied in a state where the opening 2a of the cap 2 is positioned above the inclined surface 91a of the mirror 91, whereby the three-color light source 1 is completed.

  As described above, in the three-color light source 1, the red LD11, the green LD12, the blue LD13, the first collimating lens 61, the second collimating lens 62, the third collimating lens 63, the first wavelength filter 81, and the second wavelength filter. 82 is mounted on the carrier 30. The carrier 30 is mounted on the TEC 40. Therefore, by controlling the temperature of the TEC 40 using an ATC (Automatic Temperature Controller), the temperatures of the red LD 11, the green LD 12, and the blue LD 13 are maintained constant. Accordingly, the light emitting characteristics of the red LD 11, the green LD 12, and the blue LD 13 can be maintained constant because they are not easily affected by the ambient environmental temperature.

  In addition, by maintaining the temperature constant by the TEC 40, it is possible to suppress fluctuations in the optical coupling state between the LDs 11 to 13 and the collimating lenses 61 to 63. Therefore, the collimating properties of the laser beams LR, LG, and LB emitted from the collimating lenses 61 to 63 can be maintained high. Therefore, when the three-color mixed beam (combined light L2) is condensed in the scanning optical system connected to the subsequent stage of the three-color light source 1 (the output side of the combined light L2), astigmatism and spherical aberration are greatly reduced. It is possible to reduce the possibility of color blurring.

  In the three-color light source 1, the laser beams LR, LG, and LB (combined light L <b> 2) are reflected by the mirror 91 in a direction intersecting the main surfaces 30 a and 30 b of the carrier 30. Therefore, since the opening 2a of the cap 2 can be enlarged without increasing the height of the cap 2, the beam diameter of the combined light L2 can be easily increased.

  In the three-color light source 1, each of the collimating lenses 61 to 63 is disposed corresponding to each of the three color LDs 11 to 13. These collimating lenses 61 to 63 are mounted on the second main surface 30b of the carrier 30 via three sub-base members 71 to 73 that are independent from each other. According to such a structure, it can prevent that resin for fixing the collimating lenses 61-63 flows out to the fixing position of another collimating lenses 61-63. Accordingly, it is possible to suppress optical axis fluctuations of the red laser light LR, the green laser light LG, and the blue laser light LB emitted from the LDs 11 to 13 and perform optical axis adjustment with high accuracy.

(Second Embodiment)
Next, the three-color light source 101 according to the second embodiment will be described. 10 is a perspective view showing the appearance of the three-color light source 101, and FIG. 11 is a perspective view showing a state where the cap 102 is removed from the three-color light source 101. As shown in FIG. In FIG. 11, for the sake of convenience, some of the bonding wires B1 to B10 and the like are not shown.

  As shown in FIGS. 10 and 11, the three-color light source 101 has a first embodiment in that the output direction of the combined light L <b> 2 is a direction (front) substantially parallel to the main surfaces 30 a and 30 b of the carrier 30. Is different. The three-color light source 101 includes a cap 102 having an opening 102a on the front side. The three-color light source 101 includes a beam splitter 191 and a PD 192 in place of the mirror 91 and the PD 92 of the first embodiment. The beam splitter 191 is a translucent mirror, for example. The function of the PD 192 is the same as the function of the PD 92 of the first embodiment.

  The beam splitter 191 is held in an inclined state in contact with the inclined surface 131 a of the pedestal 131 located at the front end of the carrier 30. The beam splitter 191 has an inclined surface 191 a, and the inclined surface 191 a forms an angle of, for example, 45 degrees with respect to the second main surface 30 b of the carrier 30. The PD 192 is disposed below the slope 191a.

  Further, for example, a dielectric multilayer film is attached to the inclined surface 191a of the beam splitter 191. The inclined surface 191a has a function of reflecting a part of the combined light L2 downward. That is, the beam splitter 191 reflects a part of the combined light L2 emitted from the second wavelength filter 82 downward and transmits the remaining part forward. Thus, the inclined surface 191a is a reflecting surface that reflects the laser beams LR, LG, and LB. Laser beams LR, LG, and LB reflected downward on the inclined surface 191a enter the PD 192. The PD 192 can detect the intensity of the combined light L2 by receiving the light reflected by the inclined surface 191a of the beam splitter 191.

  Even in the three-color light source 101 of the second embodiment configured as described above, since the carrier 30 is mounted on the TEC 40, the same effect as that of the first embodiment can be obtained.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to the said embodiment, It deform | transforms in the range which does not change the summary described in each claim, or applied to another thing. There may be. That is, the present invention can be variously modified without changing the gist of the present invention.

  For example, in each of the above embodiments, the first wavelength filter that transmits the red laser light LR collimated by the first collimating lens 61 and reflects the green laser light LG collimated by the second collimating lens 62 forward. 81 is used, but it is also possible to use a wavelength filter that reflects the red laser light LR and transmits the green laser light LG instead of the first wavelength filter 81. Further, instead of the second wavelength filter 82 that transmits the combined light L1 and reflects the blue laser light LB, a wavelength filter that reflects the combined light L1 and transmits the blue laser light LB may be used.

DESCRIPTION OF SYMBOLS 1,101 ... Three color light source, 2,102 ... Cap, 2a, 102a ... Opening, 11 ... Red LD (1st laser diode), 12 ... Green LD (2nd laser diode), 13 ... Blue LD (1st) 3 laser diode), 30 carrier, 30a first main surface (main surface), 30b second main surface (main surface), 40 TEC (temperature control element), 61 first collimating lens 62 ... second collimating lens, 63 ... third collimating lens, 71 ... first sub-base member, 72 ... second sub-base member, 73 ... third sub-base member, 74 ... fourth sub Base member, 75 ... fifth sub-base member, 76 ... sixth sub-base member, 81 ... first wavelength filter, 82 ... second wavelength filter, 91 ... mirror, 91a ... slope, 91b ... bottom surface, 91c ... side, 92,1 2 ... PD (photodiode), 191 ... beam splitter, L1 ... first combined light, L2 ... second combined light, LR ... red laser light (first laser light), LG ... green laser light (second Laser beam), LB ... blue laser beam (third laser beam).

Claims (10)

A three-color light source that combines and outputs red, green, and blue laser beams,
A first laser diode chip that emits a first laser beam;
A second laser diode chip that emits a second laser beam having a wavelength different from that of the first laser beam;
A third laser diode chip for emitting a third laser beam having a wavelength different from that of the second laser beam;
A first collimating lens that is focused on the light emitting end face of the first laser diode chip and that collimates the first laser light;
A second collimating lens that is focused on the light emitting end face of the second laser diode chip and collimates the second laser light;
A third collimating lens that is focused on the light emitting end face of the third laser diode chip and that collimates the third laser light;
The first laser light collimated by the first collimating lens is transmitted, the second laser light collimated by the second collimating lens is reflected, and the first laser light and the first laser light are reflected. A first wavelength filter that outputs a first combined light obtained by combining two laser beams so that optical axes of the first and second laser beams substantially coincide with each other ;
One of transmission and reflection is performed on the first combined light, and the other of transmission and reflection is performed on the third laser light collimated by the third collimating lens. A second wavelength filter that outputs a second combined light obtained by combining the first combined light and the third laser light so that optical axes of the first combined light and the third laser light substantially coincide with each other. When,
A carrier on which the first to third laser diode chips , the first to third collimating lenses, and the first and second wavelength filters are mounted;
A temperature control element on which the carrier is mounted;
With
The first and second wavelength filters are independent parts so that the optical axes can be adjusted individually,
The carrier is formed with a step so that the first to third laser diode chips are mounted at a position higher than the first to third collimating lenses and the first and second wavelength filters. And
The carrier is directly fixed to a surface higher than the surface on which the first to third collimating lenses and the first and second wavelength filters are mounted, and each is a single first to third submount. In addition, the first to third laser diode chips are directly fixed,
The second combined light is collimated only by the first to third collimating lenses without using other lenses .
Three-color light source. The first laser beam is red, one of the second or third laser beam is green, and the other of the second or third laser beam is blue;
The three-color light source according to claim 1. A mirror that reflects part of the second combined light and transmits the remaining part;
A photodiode for detecting the intensity of the second combined light transmitted through the mirror;
The three-color light source according to claim 1 or 2. The second combined light is reflected by the mirror in a direction intersecting the main surface of the carrier.
The three-color light source according to claim 3. The mirror has a slope that is inclined with respect to the direction in which the optical axis of the second combined light extends, and a bottom surface.
The bottom surface is fixed to the carrier;
The photodiode detects the intensity of the second combined light refracted at the inclined surface of the mirror;
The three-color light source according to claim 3 or 4. The second and third laser diode chips are arranged such that the emission directions of the second and third laser beams from the second and third laser diode chips are the first and second laser diode chips from the first laser diode chip. Arranged so as to be substantially perpendicular to the laser beam emission direction,
The three-color light source according to any one of claims 1 to 5 . A base member having a main surface;
A cap covering the main surface of the base member;
Further comprising
In the space defined by the base member and the cap, the first to third laser diode chips, the first to third collimating lenses, the first and second wavelength filters, the carrier, and The temperature control element is accommodated ,
The temperature control element is provided on the main surface of the base member,
The carrier is provided on a surface opposite to the base member in the temperature control element,
The three-color light source according to any one of claims 1 to 6 . The first laser diode chip is made of a GaAs material,
The second and third laser diode chips are made of a GaN-based material,
The three-color light source according to any one of claims 1 to 7. The first and second wavelength filters are directly fixed to the flat sub-base member on the carrier by an ultraviolet curable resin,
The three-color light source according to any one of claims 1 to 8 .   The height of the optical axis of the first to third laser diode chips and the height of the optical axes of the first to third collimating lenses and the first and second wavelength filters are the same.
The three-color light source according to any one of claims 1 to 9.

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