JP2012138554A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device capable of radiating high-power laser light by combining and collecting laser light from a semiconductor laser with efficiency.SOLUTION: A light source device according to the present invention has: a light source part having a plurality of laser light output parts; an optical element having an incident part to which the light from the light source part enters, a light waveguide part for guiding and combing the incoming light, and an output part for outputting the combined light to exterior; and a light collecting member for collecting the light output from the output part of the optical element. The light waveguide part has a first region and a second region having different refraction indexes in a light axis direction. With respect to the first region, the refraction index is constant, and a surface vertical to the light axis or a cross-sectional shape of the light waveguide part is a circle, ellipse, or polygon close to circle or ellipse. With respect to the second region, the refraction index of the light axis is the largest and the refraction index of the lateral face is the smallest in at least one direction of a cross-section vertical to the light axis. Thereby, the light source device can be downsized and can give a single-peak type combined light.

Description

  The present invention relates to a light source device that combines and collects laser beams emitted from a plurality of light sources and emits high-power laser beams.

For processing using the laser light source, the light source device of the marks, because the required laser beam of high output spot can be obtained, YAG, solid-state laser and a ruby, CO 2, _He-Ne, a gas such as an excimer laser Lasers are mainly used as light sources. However, since the size of the light source itself is large, the apparatus on which the light source is mounted becomes large, and a large man-hour is required for handling such as transportation and installation. Moreover, since the light source is expensive, the apparatus is expensive and difficult to introduce. Therefore, it is desired to use a semiconductor laser that is small, light, easy to handle, and inexpensive as a light source.

  A semiconductor laser has an active layer having a thickness of about several microns sandwiched between clad layers in a semiconductor laminated structure, and emits laser light from the active layer. When the semiconductor laser having such a structure has a high output, the energy density of the end face of the semiconductor layer, which is a laser beam emitting portion, becomes extremely high, causing end face destruction. Therefore, a method for synthesizing laser light from a semiconductor laser emitted with an output that does not cause end face destruction has been proposed.

  For example, Patent Document 1 discloses synthesizing light that has been polarized or dispersed by using a polarizing prism, a dichroic prism, or the like. Patent Document 2 discloses that a rod integrator is used to synthesize laser beams from a plurality of laser light sources.

JP 2008-530596 A WO2007 / 108504 gazette

  However, when an optical prism as disclosed in Patent Document 1 is used, for example, when polarization combining is performed using a polarizing prism, a large number of polarizing prisms are required depending on the number of semiconductor lasers used. In addition, when performing wavelength synthesis using a dichroic prism, it is possible to synthesize laser beams of three wavelengths, but in order to synthesize more laser beams, a large number of dichroic prisms are still required. There is a limit to miniaturization of the device.

  In addition, when a rod integrator whose side surface is parallel to the optical axis as disclosed in Patent Document 2 can be used, it is possible to synthesize laser light incident on the inside of the rod integrator. Since the spread angle (radiation angle) is large, the lens diameter for condensing it becomes large, and it is difficult to reduce the size of the apparatus. Furthermore, if a rod integrator with a rectangular entrance surface (cross section) is used, the intensity distribution on the exit surface becomes a composite light with a uniform intensity. It is difficult to obtain synthetic light.

  In addition, when using a laser light source for processing or marking, the device with the optimum condensing spot diameter must be selected according to the size of the target component, and if the target component is changed, the device is changed. There must be. Further, instead of changing the device itself, another means is known in which the spot diameter is changed to an optimum diameter by blocking the outer peripheral light out of the light from the light source by an aperture or the like (for example, Japanese Patent Application Laid-Open No. 2005-259151). 2006-239743). However, in this case, since the light on the outer periphery is blocked, there is a wasteful amount of light, the use efficiency of the light is lowered, and there is a problem when a high-power laser beam is required.

Means for Solving the Problems and Effects of the Invention

  In order to solve the above problems, the light source device of the present invention includes a light source unit having a plurality of laser beam emitting units, an incident unit to which light from the light source unit is incident, and incident light that is guided and synthesized. The light source device includes an optical element having an optical waveguide section, an output section from which the synthesized light is output to the outside, and a condensing member that condenses the light output from the output section of the optical element. The optical waveguide unit has first and second regions having different refractive indexes in the optical axis direction, and the first region has a constant refractive index and a surface perpendicular to the optical axis of the optical waveguide unit. Alternatively, the cross-sectional shape is any of a circle, an ellipse, a circle, or a polygon close to an ellipse, and the second region has the highest refractive index of the optical axis in at least one direction of the cross section perpendicular to the optical axis, and the side surface. Is characterized by the smallest refractive index.

  With such a configuration, the light emitted from the optical element can be combined light having an intensity distribution having one or two peaks, and the spread of the radiation angle of the combined light can be suppressed. Therefore, the combined light can be efficiently condensed without increasing the diameter of the condensing member, and the combined light having a single-peak intensity distribution can be obtained, and the spot diameter of the condensed combined light is optimal for use. Can be of any size.

FIG. 1A is a diagram illustrating a configuration of a light source device according to an embodiment of the present invention. 1B is a cross-sectional view of the optical element in FIG. FIG. 2 is a graph showing the intensity distribution of the laser beam synthesized by the light source device according to the embodiment of the present invention. FIG. 3A is a cross-sectional view perpendicular to the optical axis of the first region of the optical waveguide portion of the optical element according to one embodiment of the present invention. FIG. 3B is a cross-sectional view perpendicular to the optical axis of the first region of the optical waveguide portion of the optical element according to one embodiment of the present invention. FIG. 4 is a cross-sectional view including the optical axis of the optical element according to one embodiment of the present invention. FIG. 5A is a cross-sectional view perpendicular to the optical axis of the second region of the optical waveguide portion of the optical element according to one embodiment of the present invention. FIG. 5B is a refractive index distribution of the second region of the optical waveguide portion of the optical element according to one embodiment of the present invention. FIG. 6 is a cross-sectional view including the optical axis of the optical waveguide portion of the optical element according to one embodiment of the present invention, and a cross-sectional view perpendicular to the optical axes of the first region and the second region. FIG. 7 is a cross-sectional view perpendicular to the optical axis of the second region of the optical waveguide portion of the optical element according to one embodiment of the present invention. FIG. 8 is a cross-sectional view including the optical axis of the optical waveguide portion of the optical element according to one embodiment of the present invention. FIG. 9 is a perspective view of the second region of the optical waveguide portion of the optical element according to one embodiment of the present invention. FIG. 10 is a cross-sectional view including the optical axis of the optical waveguide portion of the optical element according to one embodiment of the present invention. FIG. 11 is a cross-sectional view including the optical axis of the optical element according to one embodiment of the present invention. FIG. 12 is a cross-sectional view including the optical axis of the optical element according to one embodiment of the present invention. FIG. 13 is a diagram illustrating a configuration of an optical device according to an embodiment of the present invention.

The best mode for carrying out the present invention will be described below with reference to the drawings. However, the form shown below illustrates the light source device for embodying the technical idea of the present invention, and is not limited to the following.
Further, the present specification by no means specifies the member shown in the claims as the member of the embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments are not intended to limit the scope of the present invention only to the extent that there is no specific description. It is just an example. It should be noted that the size and positional relationship of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description will be omitted as appropriate.

<Embodiment 1>
The configuration of the light source device of this embodiment is shown in FIG. 1A. FIG. 1B is a cross-sectional view of the optical element 2 of FIG. 1A along the AA plane including the optical axis Z, and is a diagram for explaining the refractive indexes of the first region and the second region. In the present embodiment, the light source device includes a light source unit 1, an optical element 2, and a lens 3 that is a condensing member. The light source unit 11 includes a plurality of laser light sources 11 in which a semiconductor laser chip is mounted in a package such as metal, resin, or ceramic. Laser light is emitted from each laser light source 11 toward the incident unit 21 of the optical element 2. Exit. The rod-shaped optical element 2 made of a light-transmitting optical member has one end (end face) as an incident part 21 and the other end (end face) as an exit part 23, which are connected via an optical waveguide part 22. The optical waveguide 22 is optically continuous and has an optical axis Z at the center of the optical waveguide 22.

  A plurality of laser beams respectively emitted from the light source unit 1 and introduced into the inside from the incident unit 21 of the optical element 2 travel toward the emitting unit 23 while being repeatedly reflected by the side surface (inner surface) 22a of the optical waveguide unit 22. And synthesized. The combined light emitted from the emission part 23 of the optical element 2 is collected by the lens 3.

  And in this Embodiment, the optical waveguide part 22 of the optical element 2 has the 1st area | region 221 (221a, 221b) from which an optical characteristic differs, and a 2nd area | region, It is characterized by the above-mentioned. Specifically, the first regions 221a and 221b have a constant refractive index inside, and a surface or a cross-sectional shape perpendicular to the optical axis Z of the optical waveguide section is circular, elliptical, circular, or nearly elliptical. The second region 222 has a refractive index distribution in which the refractive index of the optical axis is the largest and the refractive index of the side surface of the optical waveguide portion is the smallest in at least one direction of the cross section perpendicular to the optical axis Z. It is characterized by having. In the present specification, the “refractive index of the optical axis” refers to the refractive index in the vicinity of the optical axis of the optical waveguide section. Similarly, “the refractive index of the side surface” refers to the refractive index of the optical waveguide near the side surface.

  With such a configuration, it is possible to reduce (narrow) the emission angle of the combined light emitted from the emission unit 23 of the optical element 2. Therefore, the light can be efficiently collected by the light collecting member, and the combined light of the laser light having a unimodal intensity distribution as shown in FIG. 2 can be obtained. In the graph shown in FIG. 2, the vertical axis indicates the light intensity and the horizontal axis indicates the spot diameter. According to the present invention, it is possible to obtain a single-peak type combined light with a small spot diameter as shown in this graph. Further, in this specification, the “peak” means a portion of the FFP (far field pattern) intensity distribution which is substantially the maximum intensity, and has several intensities indicating the maximum intensity and the approximate value in the vicinity region. The part shall be included. The “single-peak type combined light” refers to combined light having an intensity distribution having one such peak.

  With reference to FIG. 1B, it is possible to control the radiation angle of the combined light by having the second region having the refractive index different between the optical axis and the side surface in the cross section perpendicular to the optical axis Z in the optical waveguide section 22. I will explain. FIG. 1B is a cross-sectional view including the optical axis Z of the optical waveguide portion 22 of the optical element 2, and an optical waveguide in which a first region 221a, a second region 222, and a first region 221b are provided in this order from the incident portion 21 side. Part 22 is shown. Here, in order to simplify the explanation, the explanation will be given by refraction of laser light from one laser light source among a plurality of laser light sources, and the side surface 22a of the optical waveguide section 22 is parallel to the optical axis. A description will be given using an optical member.

The refractive index between the light source unit and the optical element 2 and between the light collecting member (not shown) and the optical element 2 (that is, around the optical element 2) is n ₀ , and the refractive indexes of the first regions 221a and 221b are set. Let n ₁ and n ₃ respectively. The second region 222 has a refractive index of the center optical axis Z in one direction of the plane perpendicular to the optical axis Z (in this case, the vertical direction in the drawing), n _2, and the side surface ( in the drawings are controlled so that the refractive index towards the upper end and lower end) is small, the side surface has a refractive index n _2-.alpha. also by α min less than n _2. Here, it is assumed that each refractive index has a relationship of n ₀ <n ₁ = n ₃ <n ₂ −α <n ₂ .

The incident angle of the laser beam on the incident portion 21 is θ _0, and the refraction angle of the laser beam incident on the first region 221 of the optical element 2 is θ ₁ . In this case, Snell's law
n ₀ · sin θ ₀ = n ₁ · sin θ ₁ (Formula 1)
Holds.

Since the side surface of the optical waveguide section 22 is parallel to the optical axis Z, the incident angle of the laser light from the first region 221a to the second region 222 is the refraction angle θ _{1 of} the laser light incident on the first region 221a. Is the same as θ ₁ . And if the refraction angle at the optical axis of the laser light incident in the second region 222 is θ ₂ ,
n ₁ · sin θ ₁ = n ₂ · sin θ ₂ (Expression 2)
Holds.

The second region 222 has a refractive index n ₂ of the optical axis Z is higher than the refractive index of the side surface 22a of the optical waveguide section, rather than the laser beam travels straight while refracting angle theta _2, closer to the optical axis Z Propagate while bending. Therefore, the refraction angle θ ₂ ′ at the side surface having the refractive index n ₂ −α is smaller than θ ₂ ,
θ ₂ > θ ₂ ′ (Expression 3)
It becomes.

When the refraction angle θ ₃ of the laser light reflected on the side surface of the second region 222 and propagating to the first region 221b,
(N ₂ −α) · sin θ ₂ ′ = n ₁ · sin θ ₃ (Expression 4)
It becomes.

And by the above (formula 1)-(formula 4),
n ₁ · sin θ ₁ = n ₂ · sin θ ₂ > n ₂ · sin θ ₂ '> (n ₂ -α) · sin θ ₂ ' = n ₁ · sin θ ₃ (Formula 5)
That is,
n ₁ · sin θ ₁ > n ₃ · sin θ ₃ (Formula 6)
Since n ₁ = n ₃ holds,
θ ₁ > θ ₃ (Expression 7)
It becomes.

When the radiation angle θ ₀ ′ of the laser beam emitted from the emission part 23 of the first region 221b to the outside of the refractive index n ₀ is assumed,
n ₁ · sin θ ₃ = n ₀ · sin θ ₀ ′ (Expression 8)
Holds.

From (Expression 1), (Expression 7), and (Expression 8),
θ ₀ > θ ₀ ′ (Equation 9)
It becomes. That is, the angle θ ₀ ′ when emitted to the outside is smaller than the angle θ ₀ incident on the optical element 22.

  As described above, when an optical element capable of reducing the refraction angle of the emitted light of the laser beam is used, a spot having the same degree using only an optical element that does not have a region having a different refractive index (a refractive index is constant). Compared with the case where the light is condensed to a diameter, the diameter of the light condensing member (lens or the like) can be reduced, or the distance between the light emitting portion of the optical element and the light condensing member can be shortened.

  As an example, a light source device including a light source unit and a condensing member as shown in FIG. 1A using an optical element having a constant refractive index of an optical waveguide between an incident part and an emission part. In this case, it is assumed that the radiation angle of the combined light emitted from the emission part is about 20 °. Then, in order to set the spot diameter of the emitted light to 100 μm using such an optical element, a lens having a diameter of about 8 mm is required. On the other hand, when the optical element as in this embodiment having the same length in the optical axis direction and different regions (first region, second region) is used, the refractive index of the second region is used. By controlling the distribution state, for example, the emission angle of the emitted combined light can be reduced to about 10 ° or less, about half. Therefore, the lens diameter for obtaining the same spot diameter of 100 μm can be reduced by about 25% to about 6 mm. Further, if the lens having a reduced diameter of 6 mm has the same numerical aperture (NA) as that of the lens having the diameter of 8 mm, the distance from the light emitting portion of the optical element can be shortened. Can be shortened. In this way, even if the same number of members are used, they can be arranged more compactly (integrated).

  Hereinafter, each component will be described in detail.

(Optical element)
The optical element has an incident part for entering a plurality of laser beams emitted from the light source part, an optical waveguide part for which the light is guided and synthesized, and an emission part for emitting the synthesized light to the outside. In this case, the optical member is not a highly flexible member such as an optical fiber but an optical member using a highly rigid member having a linear shape with a fixed optical axis. And

  In the present embodiment, the optical waveguide portion of this optical element has at least two or more regions having different optical characteristics (refractive index) in the optical axis direction, that is, a first region and a second region. The first region has a constant refractive index inside, and a cross-sectional shape perpendicular to the optical axis of the optical waveguide portion is any of a circle, an ellipse, a circle, or a polygon close to an ellipse. The second region has the highest refractive index of the optical axis and the lowest refractive index of the side surface of the optical waveguide section in at least one direction of the cross section perpendicular to the optical axis.

  The first region has a cross section perpendicular to the optical axis having a specific shape, specifically, a circle, an ellipse, a circle, or a shape close to an ellipse, so that the combined light can be controlled to a single peak type. That is, the intensity distribution of the synthesized light can be controlled. In the second region, a region having a different refractive index is provided in at least one direction of a cross section perpendicular to the optical axis. Specifically, a refractive index distribution is provided in the radial direction to control the refraction angle of the laser beam. can do. That is, the radiation angle of the synthesized light can be controlled. As described above, by providing regions having different optical actions in the optical waveguide section, an optical device capable of emitting high-power synthesized light can be made a compact optical device with a small number of components. Hereinafter, the first region and the second region of the optical waveguide will be described in more detail.

(First region of the optical waveguide)
The first region of the optical waveguide is a region that mainly controls the intensity distribution of the synthesized light. In particular, the cross-sectional shape perpendicular to the optical axis greatly affects the waveform of the intensity distribution. First, the cross-sectional shape perpendicular to the optical axis of the first region will be described. 3A and 3B show a cross-sectional shape perpendicular to the optical axis Z at an arbitrary position in the first region 221a of the optical waveguide portion of the optical element 2. FIG. The first region can control the intensity distribution state of the combined light at the emitting portion by its cross-sectional shape. In the present embodiment, the cross-sectional shape perpendicular to the optical axis of the first region is circular or elliptical. Any of a polygon close to a circle or an ellipse is preferred. In particular, when the light emitted from the optical element is a single-peak type combined light having a peak of intensity distribution at the center, the cross-sectional shape is preferably circular as shown in FIG. 3A.

  Moreover, as shown in FIG. 3B, the single-peak type combined light similar to the above can also be obtained by making the cross-sectional shape of the first region elliptical. In the case of an ellipse, by adjusting the length ratio of the major axis and the minor axis, it can be a combined light having two intensity distribution peaks, and further, by adjusting the ratio thereof, The distance between intensity peak points can be adjusted.

  When the cross section of the first region is circular or elliptical as shown in FIGS. 3A and 3B, the side surface (inner surface) 22a of the optical waveguide section is formed by one continuous surface (curved surface). It is preferable that the combined light at the emission part is a combined light having an intensity distribution having one or two peaks. However, the same effect can be obtained with a polygon close to a circle or an ellipse. For example, when the cross-sectional shape is a hexagon, the side surface of the first region is composed of 64 planes, and in the case of a regular hexagon, the internal angle is about 174 °, so the cross-section is circular ( It is possible to reflect light that is relatively similar to that of a curved surface. In the case of a polygon, since the side surface is an aggregate of planes, the greater the number of corners, the closer to a circle or an ellipse, and the more preferable is a polygon of 64 or more, more preferably 128 or more. . Moreover, it is preferable that it is a regular polygon.

  Further, the first region may have, on its side surface, a region where the laser beam is not substantially irradiated (reflected), that is, a region that does not contribute (does not affect) the synthesis of the laser beam. The cross-sectional shape perpendicular to the optical axis may be a shape other than a circle or an ellipse (including a polygon close to them). As such a configuration, for example, in the case of having an optical waveguide whose cross section perpendicular to the optical axis is the above-mentioned circle or ellipse (including a polygon close to them) and whose side surface is an inclined surface, at least of the emission part A region having a diameter larger than the diameter (hereinafter also referred to as “large-diameter region”) may be provided in one or more regions in any region of the first region.

  Next, a cross-sectional shape parallel to the optical axis of the first region will be described. The side surface of the first region may be parallel to the optical axis as shown in FIGS. 1A and 1B, or may be inclined as shown in FIG. By tilting the side surface of the optical waveguide part, it is possible to control the radiation angle of the synthesized light emitted from the emitting part, and in particular, the inclined surface gradually spreads from the incident part to the emitting part. As a result, the radiation angle of the synthesized light can be reduced. For this reason, it is possible to further reduce the radiation angle of the combined light controlled in the second region. In the case of tilting, the angle β formed by the optical axis Z and the tilted side surface of the first region is preferably 2 ° or more and 10 ° or less, and more preferably 4 ° or more and 6 ° or less. The side surface of the second region may be similarly inclined.

  In order to make the intensity distribution of the synthesized light unimodal, the length in the optical axis direction of the first region (the length of the region having the side surface effective for synthesis) can be repeatedly reflected on that side surface. As such, it needs to be long to some extent. In the present embodiment, at least the length of the optical waveguide portion of the optical element only needs to be longer than the diameter of the emission portion, and further, the length is set to be 5 to 100 times the diameter of the emission portion. In view of handling and the size of the apparatus, it is more preferably 10 times or more and 20 times or less.

  Specifically, when the diameter of the first region is about 2 mm to 20 mm and the cross-sectional shape perpendicular to the optical axis is a circular optical element, the length of the first region in the optical axis direction is about 100 mm to 200 mm. Those are preferred. Note that the length and the diameter 2 of the first region are the regions other than the region that does not contribute to the synthesis of the laser beam, such as the large-diameter region described above, that is, the first region that contributes substantially to the synthesis of the laser beam. The length and diameter in a region having a side surface of one region. Moreover, when the 1st area | region is isolate | separated into plurality, let it be the total length of them.

  The first region is a member having a constant refractive index, and is made of optical glass or hollow. The material to be used is preferably a material that hardly absorbs laser light from the light source unit, and more preferably a material having a refractive index larger than that of the gas around the first region. For example, when the periphery of the optical element is surrounded by air (refractive index 1.0), the light is efficiently guided by using quartz glass (refractive index 1.5) as the first region of the optical element. be able to. Specific examples of the optical glass include inorganic glasses such as soda lime glass, borosilicate glass, aluminosilicate glass, and quartz glass. Among them, BK7 glass, B270 glass, SF11 glass, and PBK40 glass are exemplified. Quartz glass or the like is preferable. In particular, when an ultraviolet to blue semiconductor laser having a wavelength of 450 nm or less is used as the light source part, the change over time (deterioration) can be suppressed by using an optical element in which the first region is quartz glass which is an inorganic compound. It is possible to make it difficult to reduce the efficiency of the light synthesis power. As the organic substance, a resin having optical properties close to glass, such as an acrylic resin and a polycarbonate resin, can be used.

  Furthermore, you may have the coating | coated member which consists of a solid which has a refractive index smaller than the member which comprises the 1st area | region instead of the above gas (air) around the optical waveguide part (side surface). In particular, by using a covering member that is higher in mechanical strength than an optical element or a covering member that is highly malleable, etc., it can be used in an environment where it is susceptible to external impacts, in the process or during transportation. It can be prevented from being damaged when falling. In addition, workability is improved when a mechanical load is applied to the optical element, such as when the optical element is incorporated into a light source device using a fastening part such as an adhesive or a screw, and can be easily and stably fixed. .

  Also, when used in an environment where the ambient temperature tends to be relatively high, by providing a covering member made of a member having a higher thermal conductivity than the first region, the deterioration of the first region is reduced, and the refractive index difference It is possible to obtain a stable synthesized light by reducing the change of. The larger the difference in the refractive index between the first region and the covering member, the more preferable because it is easier to reflect on the side surface of the optical waveguide portion (it is difficult to leak outside), and it is particularly preferable that there is a difference of 0.5 or more.

  As a preferable material for the covering member, a metal, an inorganic compound, an organic compound, or the like can be used. Examples of the metal include metals or alloys such as aluminum, stainless steel, silver, and brass. Examples of the inorganic compound include ceramic and quartz glass. As the organic compound, a thermoplastic resin such as POM, a thermosetting resin, or the like can be used, and an acrylic resin that easily reflects light may be mixed therein. These may be used alone or in combination. Or you may make it laminate | stack. The covering member may also be provided in the second region. In that case, it is preferable that the first region and the second region are integrally covered with the same member, or may be covered with another member. Moreover, you may coat | cover only a 2nd area | region.

  As the first region, in addition to the optical glass, a hollow, that is, a cylindrical optical element having a hollow inside may be used. In this case, it is preferable to provide a reflecting member (mirror) capable of efficiently reflecting light from the light source unit on the side surface of the cylinder. By making the optical waveguide in the first region a cavity filled with a fluid such as gas or liquid instead of solid, light absorption can be reduced and light utilization efficiency can be improved. Therefore, compared with the 1st area | region which 1st area | regions which consist of solids, such as glass, since the frequency | count of reflection in the side surface can be increased, synthetic light can be obtained more efficiently. In other words, since the same composition can be performed with an optical element having a shorter length than the optical element made of a solid such as glass in the first region, the light source device can be further downsized. In addition, by using a fluid that can be arbitrarily moved in and out of the first region as the optical waveguide, the fluid itself in the optical waveguide whose temperature has risen due to heat generated by the synthesis of light can be moved to the outside. The composite light can be stably obtained without being affected by the change of the refractive index due to the temperature change.

When the first region is hollow, the gas filled in the cavity is preferably chemically stable and difficult to absorb the laser light from the light source part, and further, the absolute refractive index changes due to temperature changes. Less is preferred. Specifically, air (N ₂ , O ₂ ) is preferable.

  The pressure of the gas in the cavity of the first region is preferably normal pressure (atmospheric pressure) to vacuum, and the purpose and application in consideration of the wavelength of the light source part, the composition of the gas, and cost and ease of handling. Can be adjusted according to. For example, when using a semiconductor laser having a relatively short wavelength such as ultraviolet light as a light source unit, the absorption of light in the first region can be reduced by using a gas having a low density (for example, vacuum), Synthetic light can be obtained efficiently. Also, when a semiconductor laser with a wavelength that absorbs very little light in a gas at normal pressure, such as visible light, is used as the light source, the atmospheric pressure does not significantly affect the synthesis of light. Therefore, the apparatus and the like are not required, and handling becomes easy.

  As the hollow first region, a single member or a plurality of members stacked in a concentric direction with the optical axis as the center, or a member in which different members are joined in the optical axis direction can be used. In addition, a metal cylinder, or a cylinder provided with a reflection member capable of reflecting laser light on the side surface of a cylinder made of resin or the like can be used. Specifically, aluminum, stainless steel, silver, brass, and the like can be given, and these can be used alone, in an alloy, or laminated. For example, it is possible to use an aluminum cylinder whose side surface is coated with a high laser beam reflectance such as silver or a dielectric multilayer film. Moreover, the side surface of the cylindrical body made of acrylic resin, such as silver or a dielectric multilayer film, etc. can be used.

(Second area of the optical waveguide)
The second region of the optical waveguide section mainly controls the refraction angle (traveling direction) of the laser light guided inside, and controls the radiation angle of the combined light. In particular, by providing a region having a different refractive index in at least one direction in a cross section perpendicular to the optical axis, the refraction angle of laser light and further the emission angle of synthesized light are controlled.

FIG. 5A is a diagram showing a cross section perpendicular to the optical axis Z of the second region 222 of the optical waveguide section of the optical element 2, and regions having different refractive indexes in at least one direction (the vertical direction here) of the cross section. It has shown by the shading from white to black that it has. The white region including the optical axis Z has the highest refractive index, and the black region on the side surface 22a (upper and lower ends in the drawing) has the lowest refractive index in the vertical direction. FIG. 5B is a graph showing the refractive index distribution, where the vertical axis indicates the vertical position of the cross section perpendicular to the optical axis Z, and the horizontal axis indicates the refractive index. In the present embodiment, as shown in FIG. 5B (a), the refractive index n ₂ at the optical axis Z is the largest, and the refractive index n ₂ −α of the side surface 22a of the optical waveguide portion is the smallest. As described above, by having the regions having different refractive indexes in the cross section perpendicular to the optical axis Z, it is possible to guide the laser light so that it is bent rather than straight.

Further, when the difference in refractive index between the optical axis Z and the side surface 22a of the optical waveguide is made larger than that shown in FIG. 5B (a) as shown in FIG. the _{'theta 0 in' θ 0> θ 0} derived from equation 8), may be a smaller _{θ 0 '> θ 0''} . The radiation angle of the synthesized light can be further reduced. In this case, the refractive index distribution is such that the refractive index gradually decreases from the optical axis to the side surface of the optical waveguide portion, whereby the laser light can be efficiently synthesized. However, the refractive index distribution is not limited to such a Gaussian refractive index distribution. If the refractive index of the optical axis is the largest and the refractive index of the side surface is the smallest, it is effective to reduce the radiation angle. At any position, within the above refractive index range, there may be a region where the difference in the refractive index is reversed, or a region where the refractive index is constant.

  When such an optical element having a second region having a different refractive index in one direction in a cross section perpendicular to the optical axis is used, only the component in one direction is synthesized accordingly. Since such synthesized light can be collected into an elliptical spot by condensing, for example, when used as a scriber, it can be efficiently cut by setting the major axis direction of the spot as the cutting direction. Can do.

  FIG. 5C is a cross-sectional view showing the optical element 2 provided with two second regions 222a and 222b capable of multiplexing in one direction, and the first regions 221a, 221b and 221c and the second region 222a. , 222b is a cross-sectional view perpendicular to the optical axis Z. The second region 222a is provided with regions having different refractive indexes in the vertical direction, while the second region 222b is provided with regions having different refractive indexes in the left / right direction. That is, two second regions are provided so that the direction in which the difference in refractive index is provided is different by 90 ° (perpendicular). Thereby, the radiation angle of the laser beam finally synthesized can be controlled in two directions, the vertical direction and the horizontal direction. Further, when the second region having the same refractive index distribution is used, the control of the refraction angle in the vertical direction and the horizontal direction can be made the same.

  Here, the two second regions are arranged by changing the direction in which the refractive index is different by 90 °. However, the present invention is not limited to this and may be arranged at an arbitrary angle and number, for example, You may make it provide four 2nd area | regions so that it may differ 30 degrees. In FIG. 6, the cross-sectional shape perpendicular to the optical axis Z is a circle in the first region and a quadrangle in the second region. In such a case, the area of the second region is larger than the area of the first region. As shown in FIG. 7, the second region that does not overlap the first region is preferably covered with a cover P made of a member that shields the laser beam.

  The second region has a refractive index different from that of the optical axis and the side surface in a cross section perpendicular to the optical axis Z. The control unit can perform such a refractive index distribution by external control. Is preferably provided. By using the control unit, for example, when an optical device is used for processing, it is provided in, for example, liquid crystal so that the refractive index does not fluctuate when the combined light for processing is emitted to the workpiece. It can be controlled by continuously applying a constant voltage to the conductive member, and before processing, so that the combined light has a refractive index so that the desired radiation angle (spot diameter) is obtained. It can be controlled (adjusted) by changing the voltage. That is, by providing the control unit, the second region can function as a refractive index variable region. As a member of the second region having such a control unit, an optical modulation element can be used. Specifically, a liquid crystal having a conductive member as a control unit, an acousto-optic device in which an element generating ultrasonic waves such as a piezoelectric element is bonded to a crystal as a control unit, a nonlinear optical material having a conductive member as a control unit, and the like. It is done.

  Since the refractive index of the second region of the optical waveguide can be changed by external control, it is possible to easily control the refractive index without replacing the component (optical element) itself. The radiation angle of the emitted synthesized light can be controlled. Therefore, it is possible to obtain the optimum spot diameter of the synthesized light with respect to the irradiated object without changing the light condensing member, and it is possible to efficiently perform the work without replacing the parts of the processing machine using the laser light. be able to.

  A case where the second region includes liquid crystal will be described with reference to FIGS. 5A and 8. As shown in FIG. 8, in the second region 222 of the optical element 2, the liquid crystal molecules Q are sandwiched between the plate-like transparent members K1, and the side surface 22a (the upper end and the lower end in the drawing) is refracted. As a control unit for controlling the rate, a conductive member M1 for controlling the alignment state of liquid crystal molecules is provided, and the outside thereof is covered with an insulating member L1. A photoconductive layer is provided on one conductive member M1 (not shown), and a pair of alignment films (not shown) sandwiching the liquid crystal molecules Q are provided thereon. When a voltage is applied to the conductive member M1, liquid crystal molecules having different dielectric constants between the major axis and the minor axis are inclined according to the voltage value. And the inclination angle differs according to the distance from the conductive member M. That is, as shown in FIG. 8, the inclination angle is different between the liquid crystal molecules Q closer to the conductive member M1 and the liquid crystal molecules Q of the optical axis Z away from the conductive member M1. Therefore, the refractive index varies depending on the inclination angle. Since the refractive index difference between the optical axis and the side surface (side surface on which the control unit is provided) increases as the voltage value increases, the refraction of the second region by utilizing such a phenomenon, that is, by controlling the voltage. The rate distribution can be controlled.

  As shown in FIG. 8, when the transparent member K1 is arranged in the optical path, the material of the transparent member K1 is preferably a member whose refractive index is substantially equal to that of the first regions 221a and 221b. It is preferable to use these members.

The conductive member M1 preferably has a high transmittance of laser light from a laser light source and a low resistance. Specifically, indium oxide-tin oxide (ITO), tin oxide-antimony oxide (ATO), Examples include fluorine-doped tin oxide (FTO), indium oxide-zinc oxide (IZO), gallium oxide-zinc oxide (GaZnO), tin dioxide (SnO ₂ ), zinc oxide (ZnO), and combinations thereof. In particular, ITO is preferable because of its high transmittance and low electrical resistance.

  The covering member L1 covers the outer periphery so as to support the conductive member M1 and hold the liquid crystal between the pair of transparent members K1. The covering member L is also preferably a member that hardly absorbs laser light, and the same material as that of the transparent member K1 can be used.

  As the liquid crystal material, nematic liquid crystal, smectic liquid crystal, chiral nematic liquid crystal, cholesteric liquid crystal (lyotropic liquid crystal, thermotropic liquid crystal), ferroelectric liquid crystal (Ferroelectric Liquid Crystal), or anti-ferroelectric liquid crystal (Anti-ferroelectric Liquid Crystal), etc. Is mentioned.

  FIG. 9 is a perspective view showing the second region 222 of the optical element 2 similarly having liquid crystal, and FIG. 10 is an optical element 2 in which the second region 222 shown in FIG. 9 is provided in contact with the first regions 221a and 221b. FIG. The conductive member M2 is an insulating member (not shown) provided on the plate-like transparent member K2 so that different voltages are applied concentrically around the optical axis Z in a cross section perpendicular to the optical axis Z. A plurality (five in FIG. 9) are provided. By using the liquid crystal having such a structure, the inclination angle of the liquid crystal molecules Q is controlled by controlling the value of the voltage applied to each conductive member M2, and the direction from the optical axis to the side surface, that is, perpendicular to the optical axis. In the entire radial direction of a simple cross section, the second region can have the highest refractive index of the optical axis and the lowest refractive index of the side surface. In FIG. 9, five regions having different refractive indexes can be provided by the five conductive members M2 from the optical axis toward the side surface. By further finely dividing regions having different refractive indexes, the refractive index distribution can be made smooth. By making the voltage of the optical axis the highest and the voltage of the side face the lowest, the refractive index distribution of the optical axis is the largest and the refractive index of the side face is the smallest. The rate may be partially reversed. Preferably, the refractive index gradually decreases from the optical axis to the side surface.

  Such a liquid crystal can also use the same material as the liquid crystal having conductive members on the upper and lower ends. In particular, since the conductive member M2 is provided over the entire surface of the optical path, one having high translucency is preferable, and ITO is preferable.

The photoconductor is used for transferring the orientation distribution to the liquid crystal, and one having a high transmittance is used. Specifically, hydrogenated amorphous silicon (α-Si: H), amorphous hydrogenated silicone carbide (α-SiC: H), cadmium sulfide (CdS), organic photoreceptor (OPC, for example, poly-N— Vinyl carbazole, poly-N-vinylcarbazole derivatives, poly-9-vinylanthracene, or poly-9- (P-vinylphenylanthracene)), crystalline Si, crystalline GaAs, Bi ₁₂ SiO ₂₀ single crystal, etc. Can be mentioned. The film thickness is preferably 3 μm or less, particularly preferably 1 μm or less.

  The alignment film is for aligning the liquid crystal, and specific examples thereof include polyvinyl alcohol, polyimide, and polyvinyl cinnamate. The film thickness is preferably about several nm to several tens of nm, and is preferably about 50 nm. A polyimide film is particularly preferable.

  Examples of the optical modulation element constituting the second region include an acousto-optic element and a nonlinear optical element in addition to the above-described liquid crystal. The acousto-optic device is caused to vibrate with ultrasonic waves to generate a stress distribution according to its frequency and change the refractive index by photoelasticity. As a control unit of such an acousto-optic element, a piezoelectric element for generating ultrasonic waves and the like can be cited.

Nonlinear optical crystals include, for example, KTa _x Nb _1-x O ₃ (KTN), LiB ₃ O ₅ (LBO), LiNbO ₃ , LiTaO ₃ , KNbO ₃ , KTiOPO ₃ (KTP), Ba ₂ NaNb ₅ O ₁₅ ( _{BNN), K 3 Li 2 Nb} 5 O 15 (KLN), Ba 2 LiNb 5 O 15 (BLN), ZnO, LiIO 3, Sr x Ba 1-x Nb 2 O 6 (SBN), BaTiO 3, PbTiO 3, _{KH 2 PO 4 (KDP),} KD 2 PO 4 (KDP), NH 4 H 2 PO 4 (ADP), InPS 4, β-BaB 2 O 4 (BBO) , and the like. These have an electro-optic effect, and a change in refractive index proportional to the square of the electric field due to the applied voltage occurs. Therefore, like the liquid crystal, a pair of positive and negative conductive members is used as the control unit.

(First region and second region of optical waveguide)
The first region and the second region as described above can be provided one by one or two or more in the optical waveguide unit. Moreover, about arrangement | positioning, you may arrange | position alternately, respectively, 1st area | regions from which refractive index etc. differ may be adjoined, and 2nd area | regions from which refractive index distribution differs may be adjoined. When using two or more, respectively, it is good also considering each as the same member or a different member.

Regarding the relationship between the refractive indexes of the first region and the second region, it is only necessary that the refractive index of the optical axis of the second region is the largest, and for the other regions, an appropriate refractive index depending on the size of the light source device and the like. Each member can be selected so as to satisfy the following relationship. For example, as shown in FIG. 1B, the first region 221a (refractive index n ₁ ), the second region 222 (refractive index n _{2 to} n ₂ −α), and the first region 221b (refractive index n ₃ ) from the incident part side. of the optical member 2 having three areas, when placed in the atmosphere of the refractive index _{n 0, n} 0 above _{<n 1} = n 3 _{<other n 2 -α <n 2, n} 0 <n ₃ ≦ n ₁ <n ₂ −α <n ₂ , n ₀ <n ₂ −α <n ₁ = n ₃ <n ₂ , n ₀ <n ₂ −α <n ₃ ≦ n ₁ <n _{2 and the} like It may be made to become.

In particular, the refractive index (n _{2 to} n ₂ −α) of the entire second region is preferably larger than the refractive indexes n ₁ and n _{3 of} the first region, and n ₀ <n ₁ = n ₃ <n. other _{2 -α <n 2, n 0} <n 3 ≦ n 1 <n 2 -α <n 2, preferably with. Thereby, the radiation angle of synthetic light can be made small, suppressing the loss of light. In order to reduce the refraction angle of the synthesized light, it is effective to increase the difference in refractive index between the optical axis and the side surface of the second region, but depending on the material used, the refractive index of the optical axis of the second region. The difference between n ₂ and the refractive indices n ₁ and n _{3 of} the first region may not be large. In such a case, the refractive index n ₂ −α may be smaller than the refractive index n ₁ of the first region. In this case, although there is some light that is not incident on the second region, the radiation angle of the combined light can be further reduced by increasing the refractive index difference between n ₂ and n ₂ −α.

In the case where a plurality of first regions are provided, it is preferable that the refractive index on the side closer to the emitting portion is equal or smaller than the refractive index of the first region disposed on the side closer to the incident portion. That is, when two first regions are provided as shown in FIG. 1B, it is preferable to satisfy n ₁ ≧ n ₃ . Thus, the 'theta _0' in the above-described (Equation 1) ~ _{0 θ} derived from the equation (8)> θ _0, may be smaller _{θ 0 '> θ 0''} .

  The first region and the second region can be provided with arbitrary lengths, respectively. Preferably, the first region is preferably 1000 times or more and 100000 times or less that of the second region, and more preferably 1000 times or more and 10,000 times times. The following is preferable. For example, when the diameter of the first region is about 2 mm to 20 mm and the length of the first region in the optical axis direction is about 100 mm to 200 mm as exemplified above, the length of the second region in the optical axis direction The thickness is preferably 10 μm to 200 μm. When a liquid crystal is used as the second region, a length (thickness) in the direction of the optical axis of about 1 μm to 10 μm is preferable because it is easy to handle and easily obtainable. It is preferable to make the length. Therefore, even if the second region is added, the total length of the optical waveguide portion does not become extremely long. Thus, since it is preferable that the length of the second region in the optical axis direction is shorter than that of the first region, the side surface shape hardly affects the synthesis of the laser light. Therefore, for the second region, the shape of the cross section perpendicular to the optical axis may not be a specific shape, and a shape that can be easily provided by the control unit, that is, a quadrangle or a rectangle is preferable. In particular, when liquid crystal is used, the refractive index is controlled by the distance from the conductive part that is the control part. Therefore, if a different distance between the conductive members is used, the control becomes complicated. A shape in which the members are provided in parallel is preferable.

  Further, the interface between the first region and the second region is preferably an interface perpendicular to the optical axis as shown in FIG. 1A and the like, but not limited to this, as shown in FIG. The second region 222 is shaped so that the surface in the optical path of the optical element 2 is inclined with respect to the optical axis Z, that is, the interface between the first region 221 and the second region 222 is relative to the optical axis Z. It may be arranged so as to be inclined. When the first region 221 is hollow, the second region 222 can be disposed in the hollow of the cylindrical body of the optical element 2 as shown in FIG.

  The first region and the second region are preferably provided so as to be in contact with each other in the optical waveguide section. Thereby, it is possible to prevent an air layer or the like from intervening therebetween, and it is possible to efficiently combine laser beams.

In addition, although not shown in figure, you may coat | cover a part of entrance plane if it is a position which does not inhibit the entrance of the light from a light source part. Further, a part of the emission surface may be covered as long as the position does not hinder the emission of the light synthesized in the optical waveguide unit. In addition, by adjusting the film thickness and refractive index, a dielectric protective film (non-reflective coating / AR coating) in which the reflection of the laser light is reduced is applied to the incident portion (incident surface) and the emission of the optical waveguide portion of the optical element. You may provide in a part (output surface). As such an AR coat, for example, in the case of a light source unit using a semiconductor laser having a dominant wavelength of about 405 nm, AlN, Nb ₂ O ₅ , Al ₂ O ₃ , SiO _2, etc. have a thickness of about several nm to several μm. By providing this, an AR coat can be obtained.

(Light source)
The light source unit has a plurality of laser beam emitting units, and emits each laser beam toward the incident unit of the optical element. In this case, a semiconductor laser chip having a single laser light emitting portion, a light source portion having a plurality of laser light sources mounted on a package of metal, resin, ceramic, or the like, or a semiconductor laser chip having two or more emitting portions are provided. Alternatively, two or more laser light sources can be used.

  Each laser light source is preferably arranged with its angle adjusted so that its optical axis intersects the optical axis of the optical element. When the optical axis of the laser light source is tilted with respect to the optical axis of the optical waveguide of the optical element, the diameter of the incident part of the optical waveguide, the distance between the laser light source and the optical element, and the laser from the laser light source It can be arbitrarily adjusted according to the radiation angle of light. It is preferable that at least 80% or more of the total luminous flux of the laser light is incident on the incident portion of the optical waveguide, and more preferably, the entire FFP is incident. Further, the distance between the emission part of each laser light source and the incident part of the optical element can be arbitrarily selected. For example, the distances may be equal to each other, or the distances may be different. You may arrange so that it may become.

  Further, the laser light from the light source unit may be directly incident on the incident part of the optical element, or may be incident indirectly through various lenses. As the lens used here, one or two or more lenses can be used for one laser beam.

A semiconductor laser having an arbitrary wavelength can be selected, and visible light, ultraviolet light, infrared light, or the like can be used. For example, semiconductor lasers capable of oscillating ultraviolet light, blue light, and green visible light include II-VI group compound semiconductors (ZnSe and the like) and nitride semiconductors (In _X Al _Y Ga _1-XY N, 0 ≦ X, 0 ≦ Y, X + Y ≦ 1), and those using GaP can be applied. As the red semiconductor laser, GaAlAs, AlInGaP, or the like can be used. Furthermore, a semiconductor laser made of a material other than this can be used, and the wavelength, number, etc. can be appropriately selected according to the purpose and application. When the light source device is used as a laser scribe light source, it is preferable to use an ultraviolet to blue semiconductor laser whose main wavelength is 400 nm to 500 nm and whose longitudinal mode is single or multi, for example, a nitride semiconductor laser chip capable of outputting 800 mW By using twelve semiconductor lasers mounted on a metal package, a light source device capable of emitting a synthesized laser beam of about 10 W can be obtained.

(Condensing member)
A condensing member condenses the synthetic | combination light radiate | emitted from the output part of an optical element, and can use various lenses and a mirror. The combined light emitted from the optical element is a combined light composed of divergent light having a single-peak intensity distribution when a cross-sectional shape perpendicular to the optical axis is circular or a polygonal optical element close to a circle is used. By condensing the light with the condensing member, it is possible to obtain laser combined light having a single-peak intensity distribution with a small spot diameter. In addition, when an optical element having a cross-sectional shape perpendicular to the optical axis as an optical element having an elliptical shape or a polygonal shape close to an elliptical shape is used, the combined light having one or two peaks in intensity distribution can be obtained.

  The diameter of the condensing member can be selected according to the radiation angle of the synthesized light emitted from the optical element, and at least 80% or more of the total luminous flux of the synthesized light, preferably the total luminous flux of the synthesized light is incident Those having an effective diameter as described above are preferred. Furthermore, it is preferable to have an effective diameter that is about the same as or larger than the luminous flux diameter of the combined light and about 10% larger.

  As the lens, a lens having a circular cross section perpendicular to the optical axis is preferable. For example, a lens known as a condensing lens such as a convex lens, a concave lens, or a Fresnel lens can be used. Further, a GRIN lens or an axicon prism may be used. They can be variously selected according to the characteristics of the combined light from the optical element, the purpose, etc., with respect to the light collecting ability, the numerical aperture, the radius of curvature, the effective radius, the thickness in the optical axis direction, and the like. Specific examples of the lens material include inorganic compounds such as soda lime glass, borosilicate glass, aluminosilicate glass, and quartz glass. Among them, BK7 glass, B270 glass, SF11 glass, PBK40 glass, and quartz can be used. Various glasses such as glass are preferable, and they may be further subjected to a surface treatment such as an antireflection film. An organic compound can also be used, and for example, a resin having optical properties close to glass, such as an acrylic resin and a polycarbonate resin, can be used.

  One lens or mirror may be used as the light collecting member, or a plurality of lenses or mirrors may be used. In that case, what is necessary is just to be comprised so that it may have a condensing function by multiple sheets. Further, both the lens and the mirror may be used as a light collecting member.

<Embodiment 2>
The structure of the light source device of this embodiment is shown in FIG. FIG. 13 shows a light source device that uses the light source device described in Embodiment 1 as a light source unit 10 by using a plurality of sets. In the second embodiment, combined laser light is used as a light source and further combined to further reduce the coupling efficiency (light utilization efficiency) with the optical element even when many semiconductor lasers are used. Can do. When the number of semiconductor lasers to be used is increased, the tilting angle tends to be large when entering the incident portion of one optical element, and the place where the light can be efficiently incident is limited. By synthesizing in two steps or three or more steps, synthesized light can be obtained with high coupling efficiency.

  The optical element 2 used in the light source unit 10 and the optical element 20 to which the combined light is incident are the same in both the size of the first region and the second region, the cross-sectional shape, the angle of the inclined surface, and the like. A thing may be used, or a different thing may be used. Here, the second region 222 of the optical element 2 of the light source unit 10 is sandwiched between the first regions 221, and the optical element 20 of the optical element 20 is also the second region 2222 sandwiched between the first regions 2221. Used. As the lens 30, the condensing lens described in Embodiment 1 can be used for condensing the synthesized laser light, and the same lens as the lens used in the light source unit 10 or a different lens can be used. . The combined light from the light source unit 10 is preferably incident so that the optical axis thereof intersects the optical axis of the optical waveguide unit of the optical element 20. In this case, the focus of the combined light from the light source unit 10 may be made coincident with the incident part of the optical waveguide part of the optical element 20, and the focus is on the optical axis inside the incident part as shown in FIG. It is preferable to make it enter so that. In addition, by setting the spot diameter to be approximately equal to the area of the incident portion of the optical element 20, it is possible to reduce the load applied to the incident surface of the optical element 20 and suppress deterioration of light resistance. For example, the second region 222 and the second region 2222 have the same liquid crystal, and the refractive index is controlled by making the voltage applied to the second region 222 lower than the voltage applied to the second region 2222. The radiation angle of the synthesized outgoing light can be controlled.

  The light source device according to the present invention is an optical element that controls combined light obtained by combining a plurality of laser beams so as to have an intensity distribution having one or two peaks, and combines the laser beams. The optical waveguide section is provided with regions having different refractive indexes in the direction perpendicular to the optical axis, and the radiation angle can be controlled by controlling the refractive index. Therefore, without increasing the lens diameter for condensing, it is a light source device that can emit a combined light of laser light having a unimodal intensity distribution, for processing such as laser scribe, or It can be used for marks.

DESCRIPTION OF SYMBOLS 1, 10 ... Light source part 11 ... Laser light source 2, 20 ... Optical element 21 ... Incident part 22 ... Optical waveguide part 221a, 221b, 221c, 2221 ... 1st area | region 222, 222a, 222b, 2222 ... 2nd area | region K1, K2 ... Transparent members L1, L2 ... Coating members M1, M2 ... Control part (conductive member)
P ... Cover Q ... Liquid crystal molecule 22a ... Side (inner surface)
223 ... Cylinder 23 ... Output part 3, 30 ... Condensing member (lens)

Claims (13)

A light source unit having a plurality of laser beam emitting units;
An optical element having an incident part into which light from the light source part is incident, an optical waveguide part in which the incident light is guided and synthesized, and an emitting part from which the synthesized light is emitted to the outside;
A condensing member that condenses the light emitted from the emitting portion of the optical element;
A light source device comprising:
The optical waveguide unit includes a first region and a second region having different refractive indexes in the optical axis direction,
The first region has a constant refractive index, and a surface or a cross-sectional shape perpendicular to the optical axis of the optical waveguide portion is a circle, an ellipse, a circle, or a polygon close to an ellipse,
The light source device, wherein the second region has the highest refractive index of the optical axis and the lowest refractive index of the side surface in at least one direction of a cross section perpendicular to the optical axis.   2. The light source device according to claim 1, wherein the second region has the largest refractive index in the vicinity of the optical axis and the smallest refractive index in the vicinity of the side surface in the entire radial direction of the cross section perpendicular to the optical axis.   The light source device according to claim 1, wherein the second region has a refractive index distribution in which a refractive index gradually decreases from the vicinity of the optical axis to the side surface.   4. The light source device according to claim 1, wherein the second region has a control unit capable of changing a refractive index by external control. 5.   The optical device according to any one of claims 1 to 4, wherein the second region is an optical modulation element.   The light source device according to claim 5, wherein the optical modulation element includes a liquid crystal.   The optical device according to claim 5, wherein the optical modulation element includes an acoustooptic element.   The optical device according to claim 5, wherein the optical modulation element includes a nonlinear optical crystal.   9. The optical device according to claim 1, wherein the second region has a refractive index larger than that of the first region in the entire region.   The light source device according to claim 1, wherein the first region is made of optical glass or hollow.   The optical waveguide unit includes a plurality of first regions, and a refractive index of the first region closer to the emitting unit is equal to or smaller than a refractive index of the first region on the incident unit side. The light source device according to claim 10.   12. The optical device according to claim 1, wherein in the first region, a side surface of the optical waveguide portion is inclined with respect to the optical axis.   The light source device according to any one of claims 1 to 12, wherein the first region and the second region are disposed in contact with each other.