JP2007109978A - Semiconductor light source module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor light source module that is excellent in assembly ease, can cope with a change in environment, and can increase the utilization efficiency of light. <P>SOLUTION: Conversion luminous flux reflected by a half mirror MR enters the light reception surface of a light receiving element PD. In this case, the center of the light reception surface of the light receiving element PD corresponds to the center of an optical transmission path. Therefore, when the main ray of incident luminous flux passes through the center of the optical transmission path, the center of spot light SB for forming an image on the light reception surface coincides with the center of the light reception surface, thus maximizing combination efficiency. When the main ray of incident luminous flux does not pass through the center of the optical transmission path, the center of spot beams SB does not coincide with the center of the light reception surface, thus driving a lens L2 so that the center of the spot beams SB coincides with the center of the light reception surface. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor light source module that can irradiate convergent light onto end faces of, for example, optical fibers and SHG elements.

2. Description of the Related Art There is known a semiconductor light source module that condenses laser light emitted from a semiconductor laser on an end surface of an optical fiber, an SHG element, or the like (referred to as an SHG element) that forms an optical transmission path via a condensing optical system. Here, since the aperture diameter of the optical waveguide of the SHG element is about several μm, in order to increase the use efficiency of the light for condensing the spot with high accuracy, the semiconductor laser, the condensing optical system, the SHG element, etc. Need to be positioned accurately with respect to each other. However, even if they are securely fixed at the time of assembly, there is a risk that the mutual positional relationship will be distorted according to environmental changes such as temperature changes. Therefore, Patent Document 1 discloses a technique for combining the wavelength conversion element and the laser light source using a lens barrel having the same or approximate thermal expansion coefficient as that of the wavelength conversion element, thereby suppressing the influence of temperature change. ing.
JP-A-3-223727

  However, even if a lens barrel having the same or similar thermal expansion coefficient as that of the wavelength conversion element is used, it is difficult to completely eliminate the influence of the temperature change. In addition, when the humidity changes or the like, or due to vibration or the like, the positional relationship among the semiconductor laser, the condensing optical system, the SHG element, and the like may be shifted. Further, there is a demand for further simplifying the assembly of the semiconductor light source module.

  The present invention has been made in view of the problems of the prior art, and an object thereof is to provide a semiconductor light source module that is excellent in assembling property, can cope with environmental changes, and can improve the light utilization efficiency. To do.

  The semiconductor light source module according to claim 1 is a semiconductor light source that emits a light beam having a predetermined wavelength, a condensing optical system that collects a divergent light beam emitted from the semiconductor light source, and a light that is emitted from the condensing optical system. It comprises an SHG element that converts a convergent light beam into a light beam of a different wavelength and emits it, and a drive means for driving an optical element that constitutes the condensing optical system.

  According to the present invention, since the optical element is driven by the driving unit, the laser light beam that has passed through the optical element can be accurately condensed on the end of the optical transmission path. It can cope with deterioration and can be easily adjusted during assembly.

  According to a second aspect of the present invention, there is provided the semiconductor light source module according to the first aspect of the invention, in which the driving means bends or translates the optical axis of the principal ray of the light beam emitted from the semiconductor light source. Since the optical element that constitutes the condensing optical system is driven, the laser light beam that has passed through the optical element can be accurately condensed on the end of the optical transmission path.

  According to a third aspect of the present invention, there is provided the semiconductor light source module according to the first aspect of the invention, wherein the driving unit configures the condensing optical system to move a beam spot position formed by the condensing optical system. Since it has the drive means which drives the optical element to perform, the laser beam that has passed through the optical element can be focused on the end of the optical transmission line with high accuracy.

  A semiconductor light source module according to a fourth aspect is the invention according to any one of the first to third aspects, wherein the condensing optical system is composed of a plurality of optical elements, and the driving means is at least one of them. Therefore, a low-cost configuration is provided.

  According to a fifth aspect of the present invention, there is provided the semiconductor light source module according to the fourth aspect of the invention, wherein the plurality of optical elements include an optical system having a positive refractive power or a refractive power of zero and having a positive refractive power. Since the elements have different powers, the amount of movement of the spot light is smaller than the driving amount of the optical element, and high-accuracy positioning is possible. Further, when the optical element closest to the optical transmission path is driven to move the position of the spot light, the optical coupling efficiency to the optical transmission path is reduced with respect to the deviation of the optical element from the predetermined position. It can be kept low.

  The semiconductor light source module according to claim 6 is the invention according to claim 5, wherein the refractive power of the optical element closest to the semiconductor light source is higher than the refractive power of the optical element closest to the optical transmission path. Therefore, the amount of movement of the spot light is smaller than the driving amount of the optical element, and positioning with high accuracy is possible. Further, when the optical element closest to the optical transmission path is driven to move the position of the spot light, the optical coupling efficiency to the optical transmission path is reduced with respect to the deviation of the optical element from the predetermined position. It can be kept low.

  The semiconductor light source module according to claim 7 is characterized in that, in the invention according to claim 5, the light beam from the semiconductor light source is collimated into substantially parallel light by the optical element closest to the semiconductor light source. For example, if the optical element closest to the semiconductor light source converts the divergent light beam emitted from the semiconductor light source into a substantially parallel light beam, and the optical element closest to the optical transmission path converts the substantially parallel light beam into a convergent light beam. The drive amount of the optical element closest to the optical transmission path is equal to the movement amount of the spot light position, and high-accuracy positioning is possible. Further, when the optical element closest to the optical transmission path is driven to move the position of the spot light, the optical coupling efficiency to the optical transmission path is reduced with respect to the deviation of the optical element from the predetermined position. It can be kept low.

  The semiconductor light source module according to claim 8 is characterized in that, in the invention according to claim 7, the collimated light beam is condensed on the optical transmission line via a single condensing element. Cost reduction and compactness can be achieved.

  According to a ninth aspect of the present invention, in the semiconductor light source module according to the eighth aspect of the present invention, an aperture limiting diaphragm is integrally provided in the one light condensing element. Unnecessary light that does not propagate can be cut.

  The semiconductor light source module according to claim 10 is characterized in that, in the invention according to claim 7, the collimated light beam is condensed on the optical transmission line via two condensing elements. The amount of movement of the spot light position is smaller than the driving amount of the optical element, and high-precision positioning is possible. For example, the focal length of the first optical element is F, the focal length of the second optical element is f, the displacement amount of the spot position is δ, and when the first optical element is driven, the movement amount is Δ. Then, δ / Δ = f / F, and if this is less than 1, the spot position is displaced as compared with the case where the collimated light beam is condensed on the optical transmission line through only one optical element. Since the amount of displacement of the optical element with respect to the amount can be reduced, more accurate positioning is possible.

The semiconductor light source module according to claim 11 is the invention according to any one of claims 1 to 10, wherein f is a focal length of the optical element driven by the driving means, and When the distance to the output end of the optical transmission line is L, the following conditional expression is satisfied.
0.18 ≦ f / L ≦ 0.45 (1)

  Conditional expression (1) defines the appropriate relationship between the focal length f of the optical element driven by the driving means and the distance L from the emission end of the semiconductor light source to the emission end of the optical transmission line. When the value f / L exceeds the lower limit of the conditional expression (1), a large spot correction allowable range can be secured. On the other hand, when the value f / L is made lower than the upper limit of the conditional expression (1), it is possible to secure a sufficient length of the optical transmission line and increase the conversion efficiency of the SHG element.

  A semiconductor light source module according to a twelfth aspect is characterized in that, in the invention according to any one of the eighth to eleventh aspects, the optical element is an anamorphic element. Even if it has a circular cross section, it can be shaped.

  The semiconductor light source module according to claim 13 is characterized in that, in the invention according to any one of claims 5 to 12, in the condensing optical system, a parallel plate is disposed in an optical path of convergent light. By tilting the parallel plate with respect to the optical axis, the position of the spot light can be arbitrarily adjusted.

  A semiconductor light source module according to a fourteenth aspect is the invention according to any one of the fifth to twelfth aspects, wherein the condensing optical system is different in the direction perpendicular to the optical axis of the incident light in the optical path of the convergent light. Since the prism whose thickness changes in the two directions is arranged, the position of the spot light can be arbitrarily adjusted by displacing the prism in the direction perpendicular to the optical axis. In addition, the spot position can be adjusted because the displacement direction of the prism is not limited to the direction orthogonal to the optical axis, so that the optimum displacement direction can be selected according to the layout of the entire optical system.

  A semiconductor light source module according to a fifteenth aspect is characterized in that, in the invention according to any one of the fourth to fourteenth aspects, the driving means drives only one of the plurality of optical elements.

  A semiconductor light source module according to a sixteenth aspect is the invention according to any one of the fourth to fourteenth aspects, wherein the driving unit drives two or more of the plurality of optical elements.

  According to a seventeenth aspect of the present invention, there is provided the semiconductor light source module according to the fifth to twelfth and sixteenth aspects, wherein the driving means is the plurality of optical elements, and the optical elements having different positive refractive powers. The optical element having the smallest power is driven.

  According to an eighteenth aspect of the present invention, in the semiconductor light source module according to the eighth or ninth aspect, the driving means drives the one light collecting element.

  According to a nineteenth aspect of the present invention, in the semiconductor light source module according to the tenth aspect, the driving means drives the two light condensing elements.

  A semiconductor light source module according to a twentieth aspect of the present invention is the semiconductor light source module according to any one of the first to twentieth aspects, wherein the driving means includes an optical element constituting the condensing optical system and an optical axis direction of the semiconductor light source Since it is characterized in that it is driven in the vertical direction, it is possible to adjust the shift of the focusing position due to a temperature change. Also, initial adjustment becomes easy.

  A semiconductor light source module according to a twenty-first aspect is the invention according to any one of the first to nineteenth aspects, wherein the driving means includes an optical element constituting the condensing optical system and an optical axis direction of the semiconductor light source. It is characterized by being driven in one vertical direction.

  A semiconductor light source module according to a twenty-second aspect is the invention according to any one of the first to nineteenth aspects, wherein the driving means includes an optical element constituting the condensing optical system and an optical axis direction of the semiconductor light source. Driven independently in two directions: a vertical X-axis direction and an optical axis direction and a Y-axis direction perpendicular to the X-axis direction. Here, when there are a plurality of optical elements, one optical element is driven in the X-axis direction orthogonal to the optical axis, and the other optical element is driven in the Y-axis direction orthogonal to the optical axis and the X-axis direction. .

  A semiconductor light source module according to a twenty-third aspect is the invention according to any one of the first to twenty-second aspects, wherein the driving means moves an optical element constituting the condensing optical system in an optical axis direction of the semiconductor light source. It is characterized by being driven along.

  A semiconductor light source module according to a twenty-fourth aspect is the invention according to any one of the first to twenty-second aspects, wherein the driving means moves an optical element constituting the condensing optical system in an optical axis direction of the semiconductor light source. It is characterized by rotating around a vertical axis.

  A semiconductor light source module according to a twenty-fifth aspect is the invention according to any one of the first to twenty-second aspects, wherein the driving means moves an optical element constituting the condensing optical system in an optical axis direction of the semiconductor light source. It is characterized by being rotated only around one vertical axis.

  A semiconductor light source module according to a twenty-sixth aspect is the semiconductor light source module according to any one of the first to twenty-second aspects, wherein the driving means moves an optical element constituting the condensing optical system in an optical axis direction of the semiconductor light source. It is characterized by being rotated about a first axis and a second axis which are vertical axes and perpendicular to each other.

  A semiconductor light source module according to a twenty-seventh aspect is the invention according to any one of the first to twenty-fifth aspects, wherein the driving means includes an electromechanical conversion element and a driving member fixed to one end of the electromechanical conversion element. A movable member connected to the optical element constituting the condensing optical system and movably held on the driving member, and the electromechanical conversion element is controlled in speed in the extending direction and the contracting direction. It is characterized in that the movable member is moved by repeatedly expanding and contracting.

  According to the drive means of the present invention, the electromechanical transducer is slightly expanded or contracted by applying a drive voltage such as a sawtooth-shaped pulse to the electromechanical transducer for a very short time. The speed of expansion or contraction can be changed depending on the shape of the pulse. Here, when the electromechanical conversion element is deformed at a high speed in the extending or contracting direction, the movable member does not follow the operation of the driving member due to the inertia of the mass and remains in the same position. On the other hand, when the electromechanical conversion element is deformed in the opposite direction at a slower speed, the movable member moves following the operation of the drive member by the friction force acting therebetween. Therefore, when the electromechanical conversion element repeats expansion and contraction, the movable member can continuously move in one direction. That is, by using the driving means of the present invention having high responsiveness, the optical element connected to the movable member can be moved at a high speed and can be moved by a minute amount.

  A semiconductor light source module according to a twenty-eighth aspect is characterized in that, in the invention according to the twenty-seventh aspect, the drive member is provided with an anti-rotation mechanism.

  A semiconductor light source module according to a twenty-ninth aspect is the invention according to the twenty-eighth aspect, wherein the rotation preventing mechanism is configured such that the driving member has a rectangular cross-sectional shape and the movable member has a shape corresponding to the cross-sectional shape. It is characterized by comprising.

  A semiconductor light source module according to a thirty-third aspect is characterized in that, in the invention according to any one of the first to thirty-ninth aspects, the optical transmission line is an optical fiber.

  A semiconductor light source module according to a thirty-first aspect is the invention according to any one of the first to thirty-ninth aspects, wherein the optical transmission line is a SHG (Second Harmonic Generation) element.

  According to the present invention, it is possible to provide a semiconductor light source module that is excellent in assemblability, can cope with environmental changes, and can improve the light utilization efficiency.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a semiconductor light source module according to the present embodiment. In FIG. 1, the base BS reflects only a part of the light, a semiconductor laser LD that is a semiconductor light source, a lens L1 on the semiconductor laser LD side having a positive refractive power, a second harmonic generator H2, and the like. A half mirror MR that transmits the remainder and a light receiving element PD that receives reflected light from the half mirror MR and transmits a signal to the control circuit CNT according to the amount of received light are fixedly disposed. Further, a driving mechanism (also referred to as driving means) DR disposed on the base BS has a lens L2 on the second harmonic generator H2 side having a positive refractive power smaller than that of the lens L1 in accordance with a signal from the control circuit CNT. And the aperture stop S are driven in the direction perpendicular to the optical axis. A condensing optical system is constituted by the lens L1 and the lens L2, which are optical elements.

  The lens L1 has the surface with the larger curvature facing the optical transmission path side opposite to the semiconductor laser LD side, and the lens L2 has the surface with the larger curvature facing the semiconductor laser LD side. The lens L1 is preferably an anamorphic element. Alternatively, it is preferable that the semiconductor laser LD side of the lens 1 is a flat surface, and the other surface is an aspheric surface whose curvature decreases as the distance from the optical axis increases.

When the focal length of the lens 1 is f1 and the focal length of the lens 2 is f2, the following conditional expression is satisfied.
0.2 ≦ f1 / f2 ≦ 0.7 (1)

  FIG. 2 is a perspective view of the second harmonic generator H2. As shown in FIG. 2, the second harmonic generation device H2 has a thermoelectric cooling device HC mounted on the base BS, and is condensed on the lens L2 and is disposed on one end side of the optical waveguide (also referred to as an optical transmission path) HT. An optical waveguide SHG element HS that generates a second harmonic of incident laser light, a support HD that supports the optical waveguide SHG element HS, and a support HD that supports the optical waveguide SHG element HG. A cover HV is provided. A groove HG for placing the optical waveguide type SHG element HS is formed in the support HD.

  The optical waveguide type SHG element HS has a characteristic of converting the light passing through the optical waveguide HT into a second harmonic using a non-linear optical crystal and outputting it, and is described in Japanese Patent Application Laid-Open No. 2003-338895 etc. It is well known and will not be described in detail. The incident aperture diameter of the optical waveguide HT is not less than 1 μm and not more than 15 μm.

  FIG. 3 is a perspective view of the driving device DR. The lens L2 and the aperture stop S are held by a lens holder DH and are moved integrally. The lens holder DH serving as a movable member has a connecting portion DHa that receives a driving force.

  The connecting portion DHa is provided with a square groove DHb having a shape corresponding to and in contact with the quadrangular columnar X-axis drive axis XDS, and the leaf spring XSG with the X-axis drive axis XDS sandwiched between the square groove DHb. Is attached. An X-axis drive axis XDS, which is a drive member sandwiched between the connecting portion DHa and the leaf spring XSG, extends in a direction (X-axis direction) orthogonal to the optical axis of the lens L2, and the leaf spring XSG It is pressed moderately by the urging force. One end of the X-axis drive shaft XDS is a free end, and the other end is connected to an X-axis piezoelectric actuator XPZ that is an electromechanical transducer. The X-axis piezoelectric actuator XPZ has a connecting portion PZa.

  The connecting portion PZa is provided with a square groove PZb having a shape corresponding to and in contact with the quadrangular columnar Y-axis drive shaft YDS, and the leaf spring YSG with the Y-axis drive shaft YDS sandwiched between the square groove PZb. Is attached. The Y-axis drive shaft YDS, which is a drive member sandwiched between the connecting portion PZa and the leaf spring YSG, extends so as to be orthogonal to the optical axis and the X-axis direction of the lens L2, and is attached to the leaf spring YSG. It is moderately pressed by power. One end of the Y-axis drive shaft YDS is a free end, and the other end is connected to a Y-axis piezoelectric actuator YPZ that is an electromechanical transducer. The Y-axis piezoelectric actuator YPZ is attached to the base BS. The piezoelectric actuators XPZ and YPZ, the drive shafts XDS and YDS, the connecting portions DHa and PZa, and the leaf springs XSG and YSG constitute a drive device DR.

  The piezoelectric actuators XPZ and YPZ are formed by laminating piezoelectric ceramics formed of PZT (zircon / lead titanate) or the like. Piezoelectric ceramics have a property in which the center of gravity of the positive charge and the center of gravity of the negative charge in the crystal lattice do not coincide with each other, are themselves polarized, and extend when a voltage is applied in the polarization direction. However, since the distortion of the piezoelectric ceramics in this direction is very small and it is difficult to drive the driven member by the amount of distortion, a plurality of piezoelectric ceramics PE are stacked between the electrodes as shown in FIG. A laminated piezoelectric actuator having a structure in which C is connected in parallel is provided as a practical one. In the present embodiment, this stacked piezoelectric actuator PZ is used as a drive source.

  Next, a driving method of the lens L2 will be described. In general, a multilayer piezoelectric actuator has a small displacement when a voltage is applied, but has a large generated force and a sharp response. Therefore, when a pulse voltage having a substantially sawtooth waveform with a sharp rise and a slow fall as shown in FIG. 5A is applied to the piezoelectric actuator XPZ, the piezoelectric actuator XPZ suddenly expands and It shrinks more slowly when it falls. Therefore, when the piezoelectric actuator XPZ is extended, the X-axis drive shaft XDS is pushed to the front side in FIG. 3 by the impact force, but the connecting portion DHa of the lens holder DH holding the lens L2 and the leaf spring XSG are caused by its inertia. , It does not move together with the X-axis drive axis XDS, but slips between the X-axis drive axis XDS and stays in that position (may move slightly). On the other hand, when the pulse falls, the X-axis drive shaft XDS returns more slowly than when the pulse rises. Therefore, the connecting portion DHa and the leaf spring XSG do not slide with respect to the X-axis drive axis XDS, and are integrated with the X-axis drive axis XDS. Therefore, it moves to the back side of FIG. That is, the lens holder DH holding the lens L2 and the aperture stop S can be continuously moved in the X-axis direction at a desired speed by applying a pulse whose frequency is set to several hundreds to tens of thousands of hertz. it can. As is clear from the above, the lens holder DH can be moved in the opposite direction by applying a pulse in which the voltage rises slowly and sharply falls as shown in FIG. In the present embodiment, since the X-axis drive shaft XDS has a quadrangular prism shape (non-rotation mechanism), the anti-rotation function of the lens holder DH is exhibited and the tilt of the lens L2 is suppressed, so that a separate guide shaft is provided. There is no need.

  Similarly, when a pulse voltage having a substantially sawtooth waveform with a sharp rise and a slow fall as shown in FIG. 5A is applied to the piezoelectric actuator YPZ, the piezoelectric actuator YPZ expands rapidly at the rise of the pulse, It shrinks more slowly at the fall. Therefore, when the piezoelectric actuator YPZ is extended, the Y-axis drive shaft YDS is pushed upward in FIG. 3 by the impact force, but the connecting portion PZa of the piezoelectric actuator XPZ and the leaf spring YSG are affected by the inertia of the Y-axis drive shaft YDS. It does not move together with the Y-axis drive shaft YDS and slips in the Y-axis drive shaft YDS and stays in that position (may move slightly). On the other hand, when the pulse falls, the Y-axis drive axis YDS returns more slowly than when it rises, so that the connecting portion PZa and the leaf spring YSG do not slide with respect to the Y-axis drive axis YDS and are integrated with the Y-axis drive axis YDS. Therefore, it moves downward in FIG. That is, by applying a pulse whose frequency is set to several hundred to several tens of thousands of hertz, the piezoelectric actuator XPZ can be continuously moved together with the lens holder DH at a desired speed in the Y-axis direction. As is clear from the above, as shown in FIG. 5B, when a pulse with a slow rise and a sharp fall is applied, the piezoelectric actuator XPZ is moved in the opposite direction together with the lens holder DH. Can do. In the present embodiment, since the Y-axis drive shaft YDS has a quadrangular prism shape (non-rotation mechanism), the anti-rotation function of the piezoelectric actuator XPZ is exhibited and the tilt of the lens L2 is suppressed, so that a separate guide shaft is provided. There is no need.

  FIG. 6 is a graph showing an example of the coupling efficiency of the SHG element. In general, the light quantity of a laser beam has a Gaussian distribution with the center at its maximum. Therefore, if the chief ray of the laser beam does not coincide with the center of the optical transmission line of the SHG element, the coupling efficiency decreases. When the coupling efficiency is set to 100% in a state where the chief ray of the laser beam coincides with the center of the optical transmission path of the SHG element, and the lens is shifted from there, the center of the chief ray and the optical transmission path is thereby shifted. As shown in FIG. 6, the coupling efficiency decreases. However, the decrease in the coupling efficiency varies depending on the focal length f of the lens. That is, when the focal length f of the lens is shortened, it can be seen that the coupling efficiency of the SHG element is greatly reduced according to the displacement of the spot position. In other words, when the focal length f is shortened, the allowable range of lens shift is narrowed.

  The operation of the semiconductor light source module according to this embodiment will be described. When a laser beam having a wavelength λ is emitted from the semiconductor laser LD, the laser beam is converted into a substantially parallel light beam by the first lens L1, passes through the aperture stop S, and is condensed by the second lens L2, and then the second harmonic. It enters the optical transmission line of the wave generator H2. Here, a converted light beam converted into the second harmonic, that is, a converted light beam having a half wavelength (2 / λ) is emitted from the second harmonic generator H2, and a part of the converted light beam is reflected by the half mirror MR. The rest is output to the outside.

  The converted light beam reflected by the half mirror MR enters the light receiving surface of the light receiving element PD. Here, the center of the light receiving surface of the light receiving element PD corresponds to the center of the optical transmission path. Therefore, when the chief ray of the incident light beam passes through the center of the optical transmission path, the center of the spot light SB imaged on the light receiving surface becomes coincident with the center of the light receiving surface, so that the coupling efficiency is maximized. It becomes. On the other hand, if the principal ray of the incident light beam does not pass through the center of the optical transmission line, the center of the spot light SB does not coincide with the center of the light receiving surface as shown in FIG. Therefore, the lens L2 is driven to bend or translate the principal axis of the incident light beam so that the center of the spot light SB coincides with the center of the light receiving surface.

  FIG. 8 is a diagram showing an embodiment of the light receiving element PD. A more specific control mode will be described. In the state shown in FIG. 8A, since the light receiving amount of the light receiving unit is low, the control circuit CNT drives the driving device DR to drive the lens L2 in the positive direction of the X axis. To do. Then, as shown in FIG. 8B, the light intensity peak region LMX of the spot light SB moves accordingly, and the amount of light received by the light receiving unit increases, but if the lens L2 is moved too much in the X-axis direction. As shown in FIG. 8C, the amount of light received by the light receiving portion is low, and it is understood that the lens L2 has moved too much in the X-axis direction. Alternatively, when the lens L2 is driven in the positive direction of the X axis, the amount of light received by the light receiving unit may be low. In such a case, the position where the amount of received light becomes maximum can be detected by driving the lens L2 in the reverse direction of the X axis. In addition, by driving the lens L2 in the Y-axis direction, the position where the amount of received light is maximized can be similarly detected. In order to improve the detection accuracy, it is desirable not to drive the lens L2 when the light receiving element PD detects the amount of received light.

  Further, as another control method, when the amount of received light detected by the light receiving element PD exceeds a predetermined value, the center of the spot light SB is regarded as substantially coincident with the center of the light receiving surface, and the lens L2 is driven. Can also be omitted, which can save energy.

  When assembling the semiconductor light source module of the present embodiment, the semiconductor laser LD is assembled to the base BS, and the light beam emitted therefrom is converted into a parallel light beam via the lens L1 held by the lens holder LH. Next, using an autocollimator or the like, these parallel light beams are arranged in a line so that they pass through the optical transmission path of the second harmonic generator H2. Further, it is attached to the base BS of the lens L2 via the driving device DR. At this time, the driving device DR places the connecting portions DHa and PZa at the center of the driving axes XDS and YDS, that is, the X axis direction and the Y axis direction, respectively. In the state set at the center of the adjustment position in FIG. The fine adjustment may be performed by driving the lens L2 as described with reference to FIG. If the initial setting is performed in this way, even if the principal ray of the incident light beam is displaced in any direction with respect to the center of the optical transmission path of the second harmonic generation device H2 due to environmental changes or changes over time, Maximum correction can be performed so as to match these.

  FIG. 9 is a schematic configuration diagram of a semiconductor light source module according to the second embodiment. The present embodiment is different from the above-described embodiment in that the condensing optical system is only one lens L2. Since other configurations and operations are the same as those in the above-described embodiment, the same reference numerals are given and description thereof is omitted.

  FIG. 10 is a schematic configuration diagram of a semiconductor light source module according to the third embodiment. The present embodiment is different from the above-described embodiment in that the condensing optical system includes only three lenses L1, M, and L2. Here, only the lens M is displaced in the X-axis direction and the Y-axis direction by the driving device DR, but the lens L1 or L2 is further driven in the X-axis direction and the Y-axis direction by the same driving device. Alternatively, the lens M may be displaced only in the X-axis direction, and the lens L1 or L2 may be driven in the Y-axis direction. Since other configurations and operations are the same as those in the above-described embodiment, the same reference numerals are given and description thereof is omitted.

  Here, when the displacement amount of the spot position is δ, the optical element displacement amount is Δ, the focal length of the lens M is F, and the focal length of the lens L2 is f, δ / Δ = f / F, which is less than 1. By doing so, the amount of displacement of the optical element relative to the amount of displacement of the spot position can be made smaller than in the case of displacing one of the two optical elements, so that more accurate positioning is possible.

In the present embodiment, the lens L1 has the surface with the larger curvature facing the optical transmission path side opposite to the semiconductor laser LD side, and the lens L2 has the surface with the larger curvature facing the semiconductor laser LD side. It is aimed. In addition, a lens M having a refractive power lower than that of the lens 2 is arranged between the lens 1 and the lens 2, and the focal length of the lens 1 is f1, the focal length of the lens 2 is f2, and the focal length of the lens M is fM. The following conditional expression is satisfied.
0.1 ≦ f1 / f2 ≦ 0.6 (2)
2 ≦ | fM | / f2 ≦ 5 (3)

  In the above embodiment, the lens L2 or another lens may be displaced in the optical axis direction (in the Z-axis direction) by a similar driving device.

  FIG. 11 is a diagram illustrating a modification of the optical element. In this modification, the prism PS is driven by the driving device DR instead of the lens L2. The prism PS decreases in thickness in the X-axis direction orthogonal to the optical axis, and decreases in thickness in the Y-axis direction orthogonal to the optical axis and X-axis direction. Accordingly, since the optical path of the light beam passing through the prism PS changes according to the position where the incident light beam IL is incident, the position of the outgoing light beam OL is shifted (translated). That is, the driving device DR adjusts the principal ray of the incident luminous flux to pass through the center of the optical transmission path of the second harmonic generation device H2 by displacing the prism PS in the X-axis direction or the Y-axis direction. be able to. Since the incident light beam IL and the outgoing light beam OL are non-parallel, it is necessary to match the directions of the semiconductor laser LD and the second harmonic generator H2. It is to be noted that one prism whose thickness decreases in the X-axis direction perpendicular to the optical axis is driven in the X-axis direction, and another prism whose thickness decreases in the Y-axis direction orthogonal to the optical axis. You may make it drive in a Y-axis direction.

  FIG. 7 is a diagram showing another modification of the optical element. In this modification, a parallel plate PP is used instead of the lens L2. If the parallel plate PP is independently rotated about the axis I orthogonal to the optical axis of the semiconductor laser LD and the axis II orthogonal to the optical axis and the axis I, the position where the incident light beam enters. Accordingly, the optical path of the light beam passing through the parallel plate PP changes, so that the position of the emitted light beam shifts (translates). That is, by rotating the parallel plate PP around at least one of the axis I and the axis II by a driving device (not shown), the center of the optical transmission path of the second harmonic generator H2 is adjusted to the principal ray of the incident light beam. Can be adjusted to pass. Note that two parallel flat plates PP may be arranged, one of which rotates about the axis I and the other of which rotates about the axis II.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. For example, an optical fiber can be used instead of the second harmonic generator H2. In this case, the inside of the optical fiber becomes an optical transmission line. Furthermore, although the optical element is displaced in the above-described embodiment, it goes without saying that any one or more of the semiconductor light source, the optical element, and the optical transmission path may be relatively displaced. In addition, the light detected by the light receiving element is the wavelength converted by the SHG element (for example, 1 / of the wavelength of the semiconductor light source) even if the light is emitted from the optical waveguide (having the same wavelength as the semiconductor light source) without being wavelength converted by the SHG element. 2) Light may be used.

It is a schematic block diagram of the semiconductor light source module concerning this Embodiment. It is a perspective view of 2nd harmonic generator H2. It is a perspective view of drive device DR. FIG. 3 is a perspective view showing a multilayer piezoelectric actuator PZ having a structure in which a plurality of piezoelectric ceramics PE are stacked and electrodes C are connected in parallel therebetween. It is a figure which shows the waveform of the voltage pulse applied to the piezoelectric actuator PZ. It is a graph which shows the example of the coupling efficiency of a SHG element. It is a figure which shows another modification of an optical element. It is a figure which shows the modification of light receiving element PD. It is a schematic block diagram of the semiconductor light source module concerning 2nd Embodiment. It is a schematic block diagram of the semiconductor light source module concerning 3rd Embodiment. It is a figure which shows the modification of an optical element.

Explanation of symbols

BS Base C Electrode CNT Control circuit DH Lens holder DHa Connecting portion DHb Square groove DR Drive device H2 Harmonic wave generator HC Thermoelectric cooling device HD Support HG Groove HS Element HT Optical waveguide HV Cover IL Incident light beam L1, L2 Lens M Lens LD Semiconductor laser LH Lens holder LMX Light intensity peak area MR Half mirror OL Emitted light beam PD Light receiving element PDa Light receiving part PDb Light receiving part PDc Light receiving part PDd Light receiving part PE Piezoelectric ceramics PP Parallel plate PS Prism PZ Piezoelectric actuator PZa Connection part PZb Angular groove S Opening Aperture SB Spot light XDS X-axis drive axis XPZ X-axis piezoelectric actuator YDS Y-axis drive axis YPZ Y-axis piezoelectric actuator

Claims (31)

  A semiconductor light source that emits a light beam of a predetermined wavelength, a condensing optical system that condenses the divergent light beam emitted from the semiconductor light source, and a convergent light beam emitted from the condensing optical system is converted into a light beam of a different wavelength. A semiconductor light source module, comprising: a SHG element that emits light; and a driving unit that drives an optical element that constitutes the condensing optical system.   The drive means drives an optical element constituting the condensing optical system in order to bend or translate an optical axis of a principal ray of a light beam emitted from the semiconductor light source. 1. A semiconductor light source module according to 1.   2. The semiconductor light source module according to claim 1, wherein the driving means drives an optical element constituting the condensing optical system in order to move a beam spot position formed by the condensing optical system.   4. The semiconductor light source module according to claim 1, wherein the condensing optical system includes a plurality of optical elements, and the driving unit drives at least one of them.   5. The semiconductor light source module according to claim 4, wherein the plurality of optical elements have a positive refractive power or an optical system having a refractive power of zero, and optical elements having positive refractive power have different powers.   6. The semiconductor light source module according to claim 5, wherein the refractive power of the optical element closest to the semiconductor light source is larger than the refractive power of the optical element closest to the optical transmission path.   6. The semiconductor light source module according to claim 5, wherein a light beam from the semiconductor light source is collimated into substantially parallel light by an optical element closest to the semiconductor light source.   8. The semiconductor light source module according to claim 7, wherein the collimated light beam is condensed on the optical transmission line through a single condensing element.   9. The semiconductor light source module according to claim 8, wherein an aperture limiting diaphragm is provided integrally with the one light collecting element.   8. The semiconductor light source module according to claim 7, wherein the collimated light beam is condensed on the optical transmission line through two light condensing elements. When the focal length of the optical element driven by the driving means is f and the distance from the emission end of the semiconductor light source to the emission end of the optical transmission path is L, the following conditional expression holds: The semiconductor light source module according to claim 1, wherein the semiconductor light source module is a semiconductor light source module.
0.18 ≦ f / L ≦ 0.45 (1)   The semiconductor light source module according to claim 8, wherein the optical element is an anamorphic element.   13. The semiconductor light source module according to claim 5, wherein a parallel plate is arranged in the optical path of the convergent light in the condensing optical system.   13. The condensing optical system according to claim 5, wherein a prism whose thickness changes toward two different directions in a direction perpendicular to the optical axis of the incident light is disposed in the optical path of the convergent light. The semiconductor light source module in any one.   The semiconductor light source module according to claim 4, wherein the driving unit drives only one of the plurality of optical elements.   15. The semiconductor light source module according to claim 4, wherein the driving unit drives two or more of the plurality of optical elements.   17. The drive unit according to claim 5, wherein the drive unit drives the optical element having the smallest power among the plurality of optical elements having positive refractive powers different from each other. A semiconductor light source module according to claim 1.   10. The semiconductor light source module according to claim 8, wherein the driving unit drives the one light condensing element.   The semiconductor light source module according to claim 10, wherein the driving unit drives the two light collecting elements.   The semiconductor light source module according to claim 1, wherein the driving unit drives an optical element constituting the condensing optical system in a direction perpendicular to an optical axis direction of the semiconductor light source. .   The semiconductor light source according to claim 1, wherein the driving unit drives an optical element constituting the condensing optical system in one direction perpendicular to an optical axis direction of the semiconductor light source. module.   The driving means moves the optical elements constituting the condensing optical system in two directions: an X-axis direction perpendicular to the optical axis direction of the semiconductor light source, and an Y-axis direction perpendicular to the optical axis direction and the X-axis direction. 20. The semiconductor light source module according to claim 1, wherein the semiconductor light source module is driven independently.   23. The semiconductor light source module according to claim 1, wherein the driving unit drives an optical element constituting the condensing optical system along an optical axis direction of the semiconductor light source.   24. The semiconductor according to claim 1, wherein the driving unit rotates an optical element constituting the condensing optical system about an axis perpendicular to an optical axis direction of the semiconductor light source. Light source module.   24. The drive unit according to claim 1, wherein the driving unit rotates the optical element constituting the condensing optical system only around one axis perpendicular to the optical axis direction of the semiconductor light source. The semiconductor light source module described.   The drive means rotates the optical element constituting the condensing optical system about a first axis and a second axis that are perpendicular to the optical axis direction of the semiconductor light source and perpendicular to each other. The semiconductor light source module according to claim 1, wherein the semiconductor light source module is a light source module.   The drive means is connected to an electromechanical conversion element, a drive member fixed to one end of the electromechanical conversion element, and an optical element constituting the condensing optical system, and is movably held on the drive member. The movable member is configured to move the movable member by repeatedly expanding and contracting the electromechanical conversion element at different speeds in an extension direction and a contraction direction. Item 27. The semiconductor light source module according to any one of Items 1 to 26.   28. The semiconductor light source module according to claim 27, wherein the drive member is provided with a rotation prevention mechanism.   29. The semiconductor light source module according to claim 28, wherein the rotation preventing mechanism is configured by the drive member having a rectangular cross-sectional shape and the movable member having a shape corresponding to the cross-sectional shape. .   30. The semiconductor light source module according to claim 1, wherein the optical transmission path is an optical fiber. 30. The semiconductor light source module according to claim 1, wherein the optical transmission line is an SHG element.

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