Light-emitting device and light source device

Abstract

To provide a novel light-emitting device and a light source device, which were improved as an example.SOLUTION: A light-emitting device comprises: a capacitor lens into which, for example, a plurality of light beam arrays paralleled with an interval to a second direction while being progressed to a first direction is input; and a light emission unit group that is a light emission unit group containing a plurality of light emission units outputting a beam contained in each array, in which an optical path length that each light emission unit becomes a single mode in the second direction, outputs a beam that becomes a multi-beam in a third direction orthogonal to the first direction and the second direction, and outputs the beam as the beam output from each light emission unit is far from the beam positioned on an end of a direction opposite to the second direction of each array and the capacitor lens is long. A center line positioned at a center in the second direction of each array of each beam output from the plurality of light emission units contained in the light emission unit group is deviated to a direction opposite to the second direction to an optical shaft of the capacitor lens.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a light emitting device and a light source device. [Background technology]

[0002] Conventionally, semiconductor laser modules having multiple chip-on submounts have been known (for example, Patent Document 1). In the semiconductor laser module of Patent Document 1, an array of laser light beams output from the multiple chip-on submounts is focused by a focusing lens and coupled to an optical fiber. The semiconductor laser module is an example of a light-emitting device, the chip-on submount is an example of a light-emitting unit, and the optical fiber is an example of a coupled part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-164671 Summary of the Invention [Problem to be solved by the invention]

[0004] In a light-emitting device having a configuration in which an array of light beams output from multiple light-emitting units is focused by a focusing lens, as in Patent Document 1, there may be differences in the optical path length from each light-emitting unit to the focusing lens.

[0005] Through diligent research by the inventors, it was found that beams with a long optical path length from the light-emitting unit to the focusing lens tend to spread more easily than other beams with a short optical path length, and as a result, the coupling efficiency to the coupled part is lower than that of the other beams, and ultimately the overall coupling efficiency of multiple beams to the coupled part may be lower.

[0006] Therefore, one of the objects of the present invention is to provide an improved new light emitting device, and a light source device equipped with such a light emitting device, which can suppress a decrease in the overall coupling efficiency of the multiple beams to the coupled portion, for example, in a light emitting device having a configuration in which an array of multiple light beams is focused by a focusing lens. [Means for solving the problem]

[0007] The light emitting device of the present invention may, for example, comprise: a focusing lens whose optical axis is along a first direction and focuses light in a second direction orthogonal to the first direction, into which an array of a plurality of light beams traveling in the first direction and arranged at intervals in the second direction is input; and a light emitting unit group including a plurality of light emitting units that output the beams included in the array, each of which outputs a beam that is single mode in the second direction and multimode in a third direction orthogonal to the first direction and the second direction, and the light emitting unit group such that the farther the beam output from the light emitting unit is from a beam located at the end of the array opposite to the second direction, the longer the optical path length between the light emitting unit outputting the beam and the focusing lens, and a center line located at the center in the second direction of the array of the beams output from the plurality of light emitting units included in the light emitting unit group is shifted in the opposite direction to the second direction with respect to the optical axis of the focusing lens.

[0008] The light emitting device may include a plurality of light emitting unit groups each having a different average value of the optical path length between the plurality of light emitting units included in the light emitting unit group and the focusing lens, and the amount of deviation of the center line corresponding to each of the plurality of light emitting unit groups from the optical axis may be different from each other.

[0009] In the light-emitting device, the plurality of light-emitting unit groups may include a first light-emitting unit group and a second light-emitting unit group, and the polarization plane of the light contained in the array corresponding to the plurality of light-emitting units contained in the first light-emitting unit group and the polarization plane of the light contained in the array corresponding to the second light-emitting unit group may be orthogonal to each other.

[0010] In the light emitting device, the group of light emitting units may include the plurality of light emitting units arranged in an array.

[0011] In the light emitting device, the plurality of light emitting units included in the light emitting unit group may be arranged to be shifted from one another in the second direction.

[0012] The light emitting device may include an optical system that shifts a plurality of light beams output from the plurality of light emitting units included in the light emitting unit group and traveling along an optical path perpendicular to the second direction in a direction opposite to the second direction, and outputs the beams in a direction perpendicular to the second direction.

[0013] In the light emitting device, the optical system may include an optical component having a plurality of reflecting surfaces.

[0014] In the light emitting device, the optical system may include an optical component having a plurality of refractive surfaces.

[0015] In the light emitting device, the optical system may include a plurality of optical components each having a reflective surface.

[0016] In the light emitting device, when the width of the beam of light output from the plurality of light emitting units included in the light emitting unit group is w, the deviation of the center line corresponding to the light emitting unit group from the optical axis of the focusing lens may be 0.25w or more and w or less.

[0017] In the light emitting device, the wavelength of the light output from the light emitting unit may be 400 nm or more and 550 nm or less.

[0018] The light source device of the present invention may include the light emitting device. [Effects of the Invention]

[0019] According to the present invention, a novel and improved light emitting device and light source device can be provided. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is an exemplary schematic plan view of the optical device according to the first embodiment. [Figure 2] FIG. 2 is an exemplary schematic perspective view of a base included in the optical device of the first embodiment. [Figure 3] FIG. 3 is an exemplary schematic side view of a subunit included in the optical device of the first embodiment. [Figure 4] FIG. 4 is an exemplary schematic side view of an array of light beams input to a condenser lens of the optical device of the first embodiment. [Figure 5] FIG. 5 is an exemplary schematic cross-sectional view of an array of light beams input to a condenser lens of the optical device of the first embodiment. [Figure 6] FIG. 6 is an exemplary schematic side view of an optical system included in the optical device of the second embodiment. [Figure 7] FIG. 7 is an exemplary schematic side view of an optical system included in the optical device of the third embodiment. [Figure 8] FIG. 8 is an exemplary schematic side view of an optical system included in the optical device of the fourth embodiment. [Figure 9] FIG. 9 is an exemplary schematic plan view of the optical device according to the fifth embodiment. [Figure 10] FIG. 10 is an exemplary schematic plan view of the optical device according to the sixth embodiment. [Figure 11] FIG. 11 is an exemplary schematic perspective view of the optical device according to the seventh embodiment. [Figure 12] FIG. 12 is an exemplary configuration diagram of a light source device according to the eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] Exemplary embodiments of the present invention are disclosed below. The configurations of the embodiments described below, as well as the actions and results (effects) brought about by the configurations, are merely examples. The present invention can also be realized by configurations other than those disclosed in the following embodiments. Furthermore, according to the present invention, it is possible to obtain at least one of the various effects (including derivative effects) obtained by the configurations.

[0022] The following embodiments have similar configurations. Therefore, according to the configurations of each embodiment, similar actions and effects based on the similar configurations can be obtained. Furthermore, in the following, similar configurations are given similar reference numerals, and duplicated descriptions may be omitted.

[0023] In this specification, ordinal numbers are given for convenience to distinguish between parts, portions, directions, etc., and do not indicate priority or order.

[0024] In each figure, the X1 direction is represented by an arrow X1, the X2 direction is represented by an arrow X2, the Y direction is represented by an arrow Y, and the Z direction is represented by an arrow Z. The X1 direction, Y direction, and Z direction intersect with each other and are perpendicular to each other. The X1 direction and the X2 direction are opposite directions.

[0025] 1, 3, 4, and 6 to 10, the optical path of the laser light (beam) is indicated by a solid arrow.

[0026] [First embodiment] [Overall configuration] FIG. 1 is a schematic configuration diagram of a light emitting device 100A (100) according to the first embodiment, and is a plan view of the interior of the light emitting device 100A as viewed in the opposite direction to the Z direction.

[0027] 1, the light emitting device 100A includes a base 101, a plurality of subunits 100a, a light combining unit 108, condenser lenses 104 and 105, and an optical fiber 107. The laser light output from the light emitting unit 10A of each subunit 100a is transmitted to an end (not shown) of the optical fiber 107 via the mirror 103, the light combining unit 108, and the condenser lenses 104 and 105 of each subunit 100a, and is optically coupled to the optical fiber 107.

[0028] The base 101 is made of a material with high thermal conductivity, such as a copper-based material or an aluminum-based material. The base 101 may be composed of a single component or multiple components. The base 101 is covered with a cover (not shown). The multiple subunits 100a, the multiple mirrors 103, the light combining unit 108, the condenser lenses 104 and 105, and the end of the optical fiber 107 are all provided on the base 101 and housed in a housing chamber (not shown) formed between the base 101 and the cover. The housing chamber is hermetically sealed.

[0029] The optical fiber 107 is an output optical fiber, and is fixed to the base 101 via a fiber support portion 106a that supports the end of the optical fiber.

[0030] The fiber support portion 106a may be configured integrally with the base 101 as part of the base 101, or the fiber support portion 106a may be configured as a separate member from the base 101 and attached to the base 101 via a fastener such as a screw.

[0031] Each of the subunits 100a includes a light-emitting unit 10A that outputs a laser beam, a plurality of lenses 41A to 43A, and a mirror 103. The lenses 41A to 43A and the mirror 103 are examples of optical components. The lenses 42A and 43A collimate the laser beam in the fast axis and the slow axis.

[0032] The light-emitting device 100A also includes two arrays A1 and A2 in which a plurality of subunits 100a are arranged at predetermined intervals in the Y direction. In the subunit 100a1 (100a) of the array A1, the light-emitting unit 10A outputs laser light in the X1 direction, the lenses 41A to 43A transmit the laser light from the light-emitting unit 10A in the X1 direction, and the mirror 103 reflects the laser light traveling in the X1 direction into the Y direction. On the other hand, in the subunit 100a1 (100a) of the array A2, the light-emitting unit 10A outputs laser light in the X2 direction, the lenses 41A to 43A transmit the laser light from the light-emitting unit 10A in the X2 direction, and the mirror 103 reflects the laser light traveling in the X2 direction into the Y direction.

[0033] In this embodiment, the subunits 100a1 of array A1 and the subunits 100a2 of array A2 are aligned in the X1 direction (X2 direction). Aligning the subunits 100a1 and 100a2 in the X1 direction has the advantage of reducing the size of the light emitting device 100A in the Y direction, for example. However, this is not limiting, and the subunits 100a1 and 100a2 may be offset from each other. For example, each subunit 100a2 may be aligned in the X1 direction across the gap between two adjacent subunits 100a1 in the Y direction.

[0034] FIG. 2 is a perspective view of the base 101. As shown in FIG. 2, the surface 101b of the base 101 has a plurality of steps 101b1 (step surfaces) on which the positions of the subunits 100a are shifted in the opposite direction to the Z direction as they move in the Y direction. For each of the arrays A1 and A2 in which the subunits 100a are arranged at predetermined intervals (e.g., constant intervals) in the Y direction, the subunits 100a are provided on the respective steps 101b1. As a result, the Z-direction positions of the subunits 100a included in the array A1 shift in the opposite direction to the Z direction as they move in the Y direction, and the Z-direction positions of the subunits 100a included in the array A2 also shift in the opposite direction to the Z direction as they move in the Y direction. With this configuration, in each of the arrays A1 and A2, parallel laser beams traveling in the Y direction and aligned in the Z direction can be input from the plurality of mirrors 103 to the light combining unit 108. In array A1, the light-emitting units 10A are arranged in an array along a direction between the Y direction and the opposite direction to the Z direction, and in array A2, the light-emitting units 10A are arranged in an array along a direction between the Y direction and the opposite direction to the Z direction. That is, in array A1, the light-emitting units 10A are arranged with a shift from one another in the Z direction, and in array A2, the light-emitting units 10A are arranged with a shift from one another in the Z direction.

[0035] As shown in FIG. 1, the laser beams from the mirrors 103 are input to the light combining section 108 and combined therein.

[0036] The light combining unit 108 includes a combiner 108a, a mirror 108b, and a half-wave plate 108c. The combiner 108a, the mirror 108b, and the half-wave plate 108c are examples of optical components.

[0037] Mirror 108b directs the laser light from subunit 100a of array A1 through half-wave plate 108c to combiner 108a, which rotates the plane of polarization of the light from array A1 by 90°.

[0038] On the other hand, the laser light from the subunit 100a of array A2 is directly input to the combiner 108a. Therefore, the polarization plane of the laser light from the subunit 100a of array A2 and the polarization plane of the laser light from the subunit 100a of array A1 are orthogonal to each other.

[0039] The combiner 108a combines the laser beams from the two arrays A1 and A2. The combiner 108a is also called a polarization combining element.

[0040] The laser light from the combiner 108a is focused by the focusing lenses 104 and 105 toward an end (not shown) of the optical fiber 107, optically coupled to the optical fiber 107, and transmitted through the optical fiber 107. The focusing lens 104 focuses the laser light in the Z direction. Here, focusing the laser light in the Z direction means that the laser light that is away from the optical axis of the focusing lens 104 in the Z direction is directed toward a focusing point on the optical axis. Furthermore, the focusing lens 105 focuses the laser light in the X1 direction or the X2 direction. Here, focusing in the X1 direction or the X2 direction means that the laser light that is away from the optical axis of the focusing lens 104 in the X1 direction or the X2 direction is directed toward a focusing point on the optical axis. The focusing lenses 104 and 105 are examples of optical components.

[0041] The base 101 is also provided with a refrigerant passage 109 that cools the subunit 100a (light-emitting unit 10A), fiber support unit 106a, condenser lenses 104 and 105, combiner 108a, shielding wall 101d (described later), and the like. A refrigerant, such as a cooling liquid, flows through the refrigerant passage 109. The refrigerant passage 109 passes, for example, near the mounting surface of each component on the base 101, for example, directly below or in the vicinity thereof, and the inner surface of the refrigerant passage 109 and the refrigerant (not shown) within the refrigerant passage 109 are thermally connected to the components and parts to be cooled, i.e., the subunit 100a (light-emitting unit 10A), fiber support unit 106a, condenser lenses 104 and 105, combiner 108a, and the like. Heat is exchanged between the refrigerant and the components and parts via the base 101, thereby cooling the components. Inlet 109a and outlet 109b of refrigerant passage 109 are provided at opposite ends of base 101 in the Y direction, for example, but may be provided at other positions.

[0042] [Subunit] 3 is a plan view showing the configuration of the subunit 100a1 (100a) of the array A1. The subunit 100a2 of the array A2 has the same configuration as the subunit 100a1, although the arrangement of the optical components and the direction of transmission of the laser light are opposite to those of the subunit 100a1.

[0043] The light-emitting unit 10A has a chip-on submount 30 and a case 20 that houses the chip-on submount 30. Note that in Fig. 3, the light-emitting unit 10A is drawn with the interior of the case 20 visible.

[0044] The case 20 is a rectangular box and houses the chip-on submount 30. The case 20 has a wall member 21 and a window member 22. The wall member 21 is made of, for example, a metal material.

[0045] The case 20 also has a base 21a. The base 21a has a plate-like shape that intersects with the Z direction. The base 21a is, for example, a part (bottom wall) of the wall member 21. The base 21a is made of a metal material with high thermal conductivity, such as oxygen-free copper. Oxygen-free copper is an example of a copper-based material. The base 21a may be provided separately from the wall member 21.

[0046] An opening 21b is provided at the end of the wall member 21 in the X1 direction. A window member 22 that transmits laser light L is attached to the opening 21b. The window member 22 intersects and is perpendicular to the X1 direction. The laser light L emitted from the chip-on submount 30 in the X1 direction passes through the window member 22 and exits the light-emitting unit 10A. The laser light L is emitted from the light-emitting unit 10A in the X1 direction.

[0047] The boundaries between the multiple members (not shown) that make up the wall member 21 (case 20) and the boundary between the wall member 21 and the window member 22 are sealed to prevent gas from passing through. In other words, the case 20 is hermetically sealed. The window member 22 is also a part of the wall member 21.

[0048] The chip-on submount 30 includes a submount 31 and a light-emitting element 32 .

[0049] The submount 31 has, for example, a plate shape that intersects with and is perpendicular to the Z direction. The submount 31 can be made of an insulating material with relatively high thermal conductivity, such as aluminum nitride, ceramic, or glass. A metallized layer 31a is formed on the submount 31 as an electrode that supplies power to the light-emitting element 32.

[0050] The submount 31 is mounted on the base 21a. The light-emitting element 32 is mounted on the top surface of the submount 31. That is, the light-emitting element 32 is mounted on the base 21a via the submount 31, and is also mounted on the base 101 via the submount 31 and the case 20.

[0051] The light-emitting element 32 is, for example, a semiconductor laser element having a fast axis (FA) and a slow axis (SA). The light-emitting element 32 has an elongated shape extending in the X1 direction. The light-emitting element 32 emits laser light L in the X1 direction from an emission opening (not shown) provided at an end portion in the X1 direction. The chip-on submount 30 is mounted so that the fast axis of the light-emitting element 32 is aligned with the Z direction and the slow axis is aligned with the Y direction. The Z direction is an example of the fast axis direction, and the Y direction is an example of the slow axis direction.

[0052] The light emitting element 32 outputs laser light L having a wavelength of, for example, 400 nm or more and 1200 nm or less. The laser light L is output from the light emitting element 32 in a single mode in the fast axis direction (Z direction) and in a multimode in the slow axis direction (Y direction).

[0053] Laser light L emitted from light-emitting element 32 passes through lens 41A, lens 42A, and lens 43A in this order, and is collimated at least in the Z direction and the Y direction. Lens 41A, lens 42A, and lens 43A are all provided outside case 20.

[0054] In this embodiment, the lens 41A, the lens 42A, and the lens 43A are arranged in this order in the X1 direction. The laser light L emitted from the light-emitting element 32 passes through the lens 41A, the lens 42A, and the lens 43A in this order. Furthermore, the optical axis of the laser light L is linear and extends along the X1 direction or the X2 direction from the time it leaves the light-emitting element 32, passes through the lens 41A, the lens 42A, and the lens 43A, and reaches the mirror 103. Furthermore, during this time, the fast axis direction of the laser light L extends along the Z direction, and the slow axis direction of the laser light L extends along the Y direction.

[0055] The lens 41A is slightly spaced apart from the window member 22 in the X1 direction, or is in contact with the window member 22 in the X1 direction.

[0056] The laser light L that has passed through the window member 22 is incident on the lens 41A. The optical functional portion of the lens 41A has, for example, an axisymmetric shape with respect to a central axis Ax along the optical axis, and has the shape of a body of revolution around the central axis Ax. The lens 41A is disposed so that the central axis Ax is along the X1 direction and overlaps with the optical axis of the laser light L. The incident surface 41a and the exit surface 41b of the lens 41A each have a surface of revolution around the central axis Ax that extends in the X1 direction. The exit surface 41b is a convex curved surface that is convex in the X1 direction. The exit surface 41b protrudes more than the incident surface 41a. The lens 41A is a so-called convex lens, and is also called a condenser lens.

[0057] The beam width of the laser light L emitted from the lens 41A narrows as it travels in the X1 direction. The beam width is the width of a region in the beam profile of the laser light where the light intensity is equal to or greater than a predetermined value. The predetermined value is, for example, 1 / e of the peak light intensity. 2 The lens 41A focuses the laser light L in the Z direction, the Y direction, and a direction between the Z direction and the Y direction, which has the effect of reducing the aberration of the laser light L.

[0058] Lens 42A has a plane-symmetric shape with respect to imaginary center plane Vc2, which is a plane that intersects with and is perpendicular to the Z direction. Incident surface 42a and exit surface 42b of lens 42A have cylindrical surfaces that extend in the Y direction and have generatrices along the Y direction. Incident surface 42a is a convex curved surface that is convex in the direction opposite to the X1 direction. Also, exit surface 42b is a concave curved surface that is concave in the X1 direction.

[0059] The lens 42A collimates the laser light L in the Z direction, i.e., in the fast axis, such that the beam width Wzc in the Z direction is smaller than the beam width Wza in the Z direction at the incident surface 41a of the lens 41A. The lens 42A is a concave lens in a cross section perpendicular to the Y direction. The lens 42A is also referred to as a collimating lens.

[0060] Furthermore, lens 42A is positioned closer to lens 41A than the focal point Pcz in the Z direction of laser light L formed by lens 41A. If lens 42A were positioned farther from lens 41A than the focal point Pcz in the Z direction, the focal point Pcz in the Z direction would appear on the optical path of laser light L between lens 41A and lens 42A. In this case, there is a risk of problems such as dust accumulating at the focal point Pcz in the Z direction, where the energy density is high. In this regard, in the present embodiment, lens 42A is positioned closer to lens 41A than the focal point Pcz in the Z direction, so that laser light L is collimated by lens 42A before reaching the focal point Pcz. In other words, according to the present embodiment, the focal point Pcz in the Z direction does not appear on the optical path of laser light L, and therefore, problems caused by the focal point Pcz can be avoided.

[0061] The focal point (not shown) of the laser light L in the Y direction appears between the lens 41A and the lens 42A, but since the energy density at the focal point in the Y direction is not very high, problems such as dust accumulation do not occur.

[0062] The beam width in the Y direction of laser light L emitted from light-emitting element 32 and passing through lenses 41A and 42A increases as it travels in the X1 direction. Laser light L, which is tapered and expanding in the Y direction, enters lens 43A via lens 42A.

[0063] The optically functional portion of lens 43A has a shape that is plane-symmetrical with respect to an imaginary center plane that intersects with and is perpendicular to the Y direction. Incident surface 43a and exit surface 43b of lens 43A have cylindrical surfaces that extend in the Z direction and have generatrices along the Z direction. Incident surface 43a is a plane that is perpendicular to the X1 direction. Exit surface 43b is a convex curved surface that is convex in the X1 direction.

[0064] Lens 43A collimates laser light L in the Y direction, i.e., in the slow axis. Lens 43A is a convex lens in a cross section perpendicular to the Z direction. Lens 43A is also called a collimating lens.

[0065] [Array of beams of laser light] 4 is a side view showing the optical paths of a plurality of laser beams B from subunit 100a2 included in array A2 (see FIG. 1) of subunit 100a2, passing through condenser lenses 104 and 105 to optical fiber 107 as a coupled portion. Note that each optical path shown in FIG. 4 indicates the central axis (optical axis) of each beam B.

[0066] As described above, in array A2 of subunit 100a2, the multiple laser beams B reflected by each mirror 103 all travel in the Y direction, are arranged at approximately equal intervals in the Z direction, and are parallel to each other. From FIGS. 1 and 2, it can be seen that the beams B are reflected by mirrors 103 that are farther from condenser lens 104 in the Y direction as the beams B are farther from surface 101b in the Z direction. The optical path lengths of beams B from light-emitting unit 10A (light-emitting element 32) in subunit 100a2 to mirror 103 are the same. Therefore, for the multiple beams B shown in FIG. 4, the farther from surface 101b, in other words, the farther from beam Bn located at the end opposite in the Z direction, or further forward in the Z direction (upward in FIG. 4), the longer the optical path length from light-emitting unit 10A to condenser lens 104.

[0067] As described above, the laser light is output from the light-emitting element 32 in a single mode in the fast axis direction and in a multimode in the slow axis direction. Here, in the range shown in FIG. 4, the fast axis direction of the beam B of the laser light is the Z direction, and the slow axis directions are the X1 and X2 directions. The Y direction, which is the direction in which the optical axis Ax1 of the focusing lens 104 extends and the direction in which the beam B incident on the focusing lens 104 travels, is an example of a first direction, the Z direction in which the beam is in single mode is an example of a second direction, and the X1 and X2 directions in which the beam is in multimode are examples of a third direction.

[0068] In such a configuration, the inventors have found that, in the array Ar of laser beam B shown in Fig. 4, the longer the distance from light-emitting unit 10A (light-emitting element 32) of beam B to condenser lens 104, i.e., the farther beam B is from beam Bn, the lower the coupling efficiency to optical fiber 107, resulting in a lower overall coupling efficiency of array Ar of multiple beams B to optical fiber 107. This is presumably because, in the direction in which laser beam B output from light-emitting unit 10A (light-emitting element 32) becomes multimode (X1 direction and X2 direction in the range shown in Fig. 4), the longer the optical path length from light-emitting unit 10A (light-emitting element 32) becomes, the greater the beam width in the direction in which multimode becomes.

[0069] 4, the light-emitting device 100 of this embodiment is configured so that a center line C located at the center in the Z direction of the array Ar of multiple beams B is shifted in the opposite direction of the Z direction with respect to the optical axis Ax1 of the condenser lens 104. Specifically, for example, in the light-emitting device 100, the step 101b1, the light-emitting unit 10A, the subunit 100a, the mirror 103, the condenser lens 104, the optical fiber 107, etc. are arranged so that such a shift occurs. Note that the center line C is located between the optical axis of the beam B1 located at the end in the Z direction and the optical axis of the beam Bn located at the end in the opposite direction in the Z direction, and is a virtual line extending in the Y direction.

[0070] For multiple beams B passing through the focusing lens 104 that focuses in the Z direction, due to the influence of aberrations of the focusing lens 104 and the like, the farther from the optical axis Ax1 the beam is, the lower its coupling efficiency to the optical fiber 107, and the closer to the optical axis Ax1 the beam is, the higher its coupling efficiency to the optical fiber 107. Therefore, by shifting the center line C in the opposite Z direction relative to the optical axis Ax1, beam B with a long optical path length from the light-emitting unit 10A can be brought closer to the optical axis Ax1, thereby increasing the coupling efficiency of the beam B to the optical fiber 107. When the wavelength of the laser light is 400 nm or more and 550 nm or less, the width of the beam B tends to widen. Therefore, the effect of shifting the center line C in the opposite Z direction relative to the optical axis Ax1 is particularly effective when the wavelength of the laser light is 400 nm or more and 550 nm or less.

[0071] Furthermore, here, an example has been given of the array Ar of beams B shown in Figure 4 being composed of beams B of laser light output from multiple light-emitting units 10A included in array A2 of subunit 100a2, but an array Ar similar to that of Figure 4 can also be composed of beams B of laser light output from multiple light-emitting units 10A included in array A1 of subunit 100a1, and the effect of shifting the center line C in the opposite direction of the Z axis relative to the optical axis Ax1 can be obtained, as in the case of array A2 of subunit 100a2.

[0072] FIG. 5 is a cross-sectional view of an array Ar of beams B. As shown in FIG. 5, in the array Ar, multiple beams B have the same width w in the Z direction and are arranged at a substantially constant pitch p in the Z direction. The pitch p is set to, for example, a value substantially equal to the width w. Note that the width w of beam B is the width of a region in the beam profile of the laser light where the light intensity is equal to or greater than a predetermined value. The predetermined value is, for example, 1 / e of the peak light intensity. 2 In FIG. 5, the widths of the multiple beams B in the X1 and X2 directions are all drawn to be the same, but in reality, the widths become wider as they are positioned further forward in the Z direction (upward in FIG. 5).

[0073] The inventors conducted experimental studies on the offset δ (see FIG. 4 ) of the center line C in the opposite direction to the Z direction and found that when the offset δ exceeds w (≒p), i.e., when the offset is excessive, the coupling efficiency of the beam Bn (B) located at the end in the opposite direction to the Z direction to the optical fiber 107 decreases, and as a result, the overall coupling efficiency of all beams B included in the array Ar to the optical fiber 107 decreases. Conversely, when the offset δ falls below 0.25w (≒0.25p), i.e., when the offset is insufficient, the coupling efficiency of the beam B1 (B) located at the end in the Z direction to the optical fiber 107 decreases, and as a result, the overall coupling efficiency of all beams B included in the array Ar to the optical fiber 107 decreases. That is, the inventors conducted experimental studies and found that it is preferable for the offset δ to be greater than or equal to 0.25w and less than or equal to w, or greater than or equal to 0.25p and less than or equal to p.

[0074] Furthermore, the inventors have found through experimental research that, within a range of the misalignment δ between 0.25w and w, the misalignment δ at which the overall coupling efficiency of the multiple beams B included in the array Ar to the optical fiber 107 is highest differs between the array A1 of the subunit 100a1 and the array A2 of the subunit 100a2. This is presumably due to the difference between the average optical path length between the light-emitting units 10A included in the array A1 and the condenser lens 104 and the average optical path length between the light-emitting units 10A included in the array A2 and the condenser lens 104. Therefore, it is preferable to appropriately set the misalignment δ for each of the multiple light-emitting units 10A (hereinafter referred to as a light-emitting unit group) that output the multiple beams B that constitute the array Ar. The multiple light-emitting units 10A included in the subunit 100a1 are an example of a first light-emitting unit group, and the multiple light-emitting units 10A included in the subunit 100a2 are an example of a second light-emitting unit group. As described above, the polarization plane of the beam B of laser light from the plurality of light-emitting units 10A included in subunit 100a1 and the polarization plane of the beam B of laser light from the plurality of light-emitting units 10A included in subunit 100a2 are perpendicular to each other.

[0075] As described above, in this embodiment, as shown in Fig. 4, the center line C in the Z direction of the array Ar is shifted in the opposite direction of the Z direction with respect to the optical axis Ax1 of the condenser lens 104. With this configuration, the beam B, whose coupling efficiency to the optical fiber 107 in the X1 and X2 directions is reduced due to the long optical path length from the light-emitting unit 10A, is positioned closer to the optical axis Ax1, thereby making it possible to increase the coupling efficiency of the beam B to the optical fiber 107 in the Z direction compared to when there is no such shift. This makes it possible to further increase the overall coupling efficiency of the plurality of beams B to the optical fiber 107 of the array Ar.

[0076] [Second embodiment] FIG. 6 is a side view of the optical system 110 included in the light emitting device 100B (100) of the second embodiment.

[0077] The optical system 110 shown in FIG. 6 is provided before the condenser lens 104, i.e., between the light combining unit 108 and the condenser lens 104. The optical system 110 includes an optical component 111B, such as a Dove prism, having two reflecting surfaces 111b1 and 111b2. In this case, the optical system 110 reflects the laser beam B at the reflecting surfaces 111b1 and 111b2, thereby shifting the beam B traveling in the Y direction in the opposite direction to the Z direction and outputting it in the Y direction. Note that although FIG. 6 shows the optical path of only one beam B, all beams B included in the array Ar (see FIG. 4) can pass through the optical system 110. In other words, the optical system 110 can shift all beams B included in the array Ar collectively in the opposite direction to the Z direction.

[0078] According to this configuration, by adding the optical system 110 upstream of the condenser lens 104, it is possible to relatively easily shift the center line C in the Z direction of the array Ar with respect to the optical axis Ax1 of the condenser lens 107 in the opposite direction to the Z direction, without, for example, adjusting the step 101b1 or the relative positions of the light-emitting unit 10A, the subunit 100a, the mirror 103, the condenser lens 104, the optical fiber 107, etc. That is, according to this embodiment, it is relatively easy to achieve a state in which the overall coupling efficiency of the plurality of beams B to the optical fiber 107 of the array Ar is higher. Furthermore, by preparing a plurality of optical systems 110 with different shift amounts δ and selectively installing an optical system 110 that provides a shift amount δ that results in higher coupling efficiency even when manufacturing variations occur, it is possible to relatively easily achieve a state in which the overall coupling efficiency is even higher.

[0079] The specifications of optical component 111B can be changed in various ways. For example, the number of reflecting surfaces 111b1 and 111b2 may be three or more, and the inclination angles of reflecting surfaces 111b1 and 111b2 with respect to the Y and Z directions may be different from those in the example of FIG.

[0080] [Third embodiment] FIG. 7 is a side view of the optical system 110 included in the light emitting device 100C (100) of the third embodiment.

[0081] The optical system 110 shown in FIG. 7 is also provided upstream of the condenser lens 104, i.e., between the light combining unit 108 and the condenser lens 104. The optical system 110 is an optical component 111C, such as a parallel plate, that has two refracting surfaces 111c1 and 111c2 and transmits the beam B. In this case, the optical system 110 refracts the laser beam B at the refracting surfaces 111c1 and 111c2, thereby shifting the beam B traveling in the Y direction in the opposite direction to the Z direction and outputting it in the Y direction. Note that although FIG. 7 shows the optical path of only one beam B, all beams B included in the array Ar (see FIG. 4) can pass through the optical system 110. That is, the optical system 110 can shift all beams B included in the array Ar in the opposite direction to the Z direction all at once. That is, the optical system 110 can shift all beams B included in the array Ar in the opposite direction to the Z direction all at once.

[0082] This embodiment also provides the same effects as the second embodiment. Furthermore, this embodiment also provides the advantage that the amount of deviation δ can be changed relatively easily by changing the tilt angle of the optical component 111C relative to the Z direction or the Y direction. The specifications of the optical component 111C, such as thickness, length, and shape, can be changed in various ways.

[0083] [Fourth embodiment] FIG. 8 is a side view of the optical system 110 included in the light emitting device 100D (100) of the fourth embodiment.

[0084] The optical system 110 shown in FIG. 8 is provided before the condenser lens 104, i.e., between the light combining unit 108 and the condenser lens 104. The optical system 110 has two optical components 111D, such as mirrors, each having a reflecting surface 111d. In this case, the optical system 110 reflects the laser beam B at the two reflecting surfaces 111d, thereby shifting the beam B traveling in the Y direction in the opposite direction to the Z direction and outputting it in the Y direction. Note that although FIG. 8 shows the optical path of only one beam B, all beams B included in the array Ar (see FIG. 4) can pass through the optical system 110. In other words, the optical system 110 can shift all beams B included in the array Ar collectively in the opposite direction to the Z direction.

[0085] This embodiment also provides the same effects as the second embodiment. Another advantage of this embodiment is that the deviation amount δ can be changed relatively easily by changing the arrangement of the two optical components 111D. The specifications of the optical components 111D can be changed in various ways. For example, the number of optical components 111D may be three or more, and the inclination angle of the reflecting surface 111d relative to the Y direction and the Z direction may be different from that shown in FIG. 8.

[0086] [Fifth embodiment] 9 is a plan view of a light emitting device 100E (100) according to the fifth embodiment. The light emitting device 100E has the same configuration as the light emitting device 100A (100) according to the first embodiment, except for the configuration of the optical components of the subunit 100a.

[0087] In this embodiment, the subunit 100a includes a light-emitting unit 10E, a lens 42B, a lens 43B, and a mirror 103. The light-emitting unit 10E does not include a case 20 (see FIG. 3) as in the first embodiment, but includes a chip-on submount 30. The chip-on submount 30 is exposed inside the accommodation chamber of the light-emitting device 100D. The lens 42B collimates the laser light from the light-emitting element 32 in the Z direction, i.e., in the fast axis. The lens 43B collimates the laser light from the lens 42B in the Y direction, i.e., in the slow axis.

[0088] In this embodiment, for example, by adjusting the relative positions of the step 101b1 (see FIG. 2) and the light-emitting unit 10E, subunit 100a, mirror 103, condenser lens 104, optical fiber 107, etc. as in the first embodiment, or by adding an optical system 110 as in the second to fourth embodiments before the condenser lens 104, the center line C in the Z direction of the array Ar can be shifted in the opposite direction of the Z direction with respect to the optical axis Ax1 of the condenser lens 104, as in FIG. 4. That is, this embodiment can also achieve the same effects as the first to fourth embodiments.

[0089] [Sixth embodiment] 10 is a plan view of a light emitting device 100F (100) according to the sixth embodiment. The light emitting device 100F has a similar configuration to the light emitting device 100E according to the fifth embodiment, except that the light emitting elements 32 output laser beams of mutually different wavelengths (λ1, λ2, . . . , λn-1, λn) and the light emitting device 100F does not include a half-wave plate 108c. The intervals between the multiple wavelengths are, for example, 5 nm to 20 nm between the center wavelengths. The light combined here may also include blue laser beam.

[0090] In this embodiment, for example, by adjusting the relative positions of the step 101b1 (see FIG. 2) and the light-emitting unit 10E, subunit 100a, mirror 103, condenser lens 104, optical fiber 107, etc. as in the first embodiment, or by adding an optical system 110 as in the second to fourth embodiments before the condenser lens 104, the center line C in the Z direction of the array Ar can be shifted in the opposite direction of the Z direction with respect to the optical axis Ax1 of the condenser lens 104, as in FIG. 4. That is, this embodiment can also achieve the same effects as the first to fourth embodiments.

[0091] [Seventh embodiment] Fig. 11 is a perspective view of a light emitting device 100G (100) according to the seventh embodiment. As shown in Fig. 11, in this embodiment, a plurality of light emitting units 10A are arranged on a single, flat, level surface 101b of a base 101. Laser beams from these light emitting units 10A are arranged at equal intervals in the Y direction.

[0092] Light traveling in the opposite direction of the Z direction from light-emitting unit 10A through lenses 43B and the like is first reflected in the X direction by mirror 103a, then reflected in the Y direction by mirror 103b, and travels toward condenser lens 104. Base 101 has multiple side surfaces 101f (steps) facing the Z direction and arranged in a staircase pattern. Each of side surfaces 101f intersects with the Z direction and extends in the X and Y directions. Furthermore, side surfaces 101f are offset in a step-like manner in the Z direction as they travel in the opposite direction of the Y direction. Optically connected sets of mirrors 103a and 103b are mounted on each side surface 101f. With this configuration, the light traveling in the Y direction from each mirror 103b toward condenser lens 104 is parallel to each other and arranged at equal intervals in the Z direction on the incident surface of condenser lens 104. Light from each light-emitting unit 10A is coupled to optical fiber 107 via condenser lenses 104 and 105.

[0093] In this embodiment, too, the laser light beams input to the condenser lens 104 have the same arrangement as that shown in FIG. 4. Therefore, according to this embodiment, for example, as in the first embodiment, by adjusting the relative arrangements of the side surface 101f, the mirrors 103a and 103b, the condenser lens 104, the optical fiber 107, and the like, it is possible to shift the center line C in the Z direction of the array Ar in the opposite direction to the Z direction with respect to the optical axis Ax1 of the condenser lens 104. Also in this embodiment, by adding the optical system 110 as in the second to fourth embodiments before the condenser lens 104, it is possible to shift the center line C in the Z direction of the array Ar in the opposite direction to the Z direction with respect to the optical axis Ax1 of the condenser lens 104. That is, this embodiment can also achieve the same effects as the first to fourth embodiments.

[0094] [Eighth embodiment] [Light source device] 12 is a configuration diagram of a light source device 200 of an eighth embodiment in which the light emitting device 100 of any one of the first to seventh embodiments is mounted. The light source device 200 includes a plurality of light emitting devices 100 as excitation light sources. Laser light output from the plurality of light emitting devices 100 is transmitted to a combiner 201 serving as an optical coupling unit via an optical fiber 107. The output ends of the optical fibers 107 are respectively coupled to a plurality of input ports of the combiner 201, which has multiple inputs and one output. Note that the light source device 200 is not limited to one including a plurality of light emitting devices 100, and it is sufficient that the light source device 200 includes at least one light emitting device 100.

[0095] According to the light source device 200 of this embodiment, by including the light emitting device 100 of the first to seventh embodiments, it is possible to obtain the same effects as those of the first to seventh embodiments.

[0096] While the embodiments of the present invention have been described above, they are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of each configuration, shape, and the like (structure, type, direction, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate. [Explanation of symbols]

[0097] 10A, 10E...Lighting unit 20…case 21...Wall components 21a...bass 21b...Opening 22...Window material 30...Chip-on-submount 31...Submount 31a...metallized layer 32...Light emitting element 41A...Lens 41a...Incidence surface 41b...Emission surface 42A, 42B...Lens 42a...Incidence surface 42b...Emission surface 43A, 43B...Lens 43a...Incidence surface 43b...Emission surface 100, 100A~100F...Light emitting device 100a, 100a1, 100a2... subunits 101...Bass 101b…Surface 101b1...step 101d…shielding wall 101f...Side (step) 103...Mirror 103a, 103b...Mirror 104, 105...Condenser lenses 106a...Fiber support part 107...Optical fiber 108...Photosynthesis division 108a…Combiner 108b...Mirror 108c…1 / 2 wavelength plate 109...refrigerant passage 109a...Entrance 109b…Exit 110...Optical system 111B...Optical components 111b1,111b2…Reflecting surface 111C...Optical components 111c1, 111c2...refractive surface 111D...Optical components 111d…Reflective surface 200...Light source device 201... Combiner Ax…center axis Ax1…Optical axis A1, A2...Array Ar…Array B, B1, Bn...Beam C…Center line L...laser light Pcz…Focus point p...pitch Vc2: Virtual center plane Wza: Beam width Wzc: Beam width w…width X1…direction (third direction) X2…direction (third direction) Y…direction (first direction) Z…direction (second direction) δ...deviation amount

Claims

1. a focusing lens having an optical axis along a first direction and configured to focus light in a second direction perpendicular to the first direction, the focusing lens receiving an array of light beams traveling in the first direction and spaced apart in the second direction; a light-emitting unit group including a plurality of light-emitting units that output the beams included in the array, each light-emitting unit outputting the beams that are single-mode in the second direction and multi-mode in a third direction perpendicular to the first direction and the second direction, and the farther the beams outputted from the light-emitting units are from the beams located at the end of the array opposite to the second direction, the longer the optical path length between the light-emitting unit that outputs the beams and the condenser lens; Equipped with A light emitting device, wherein a center line located at the center in the second direction of the array of the beams output from the plurality of light emitting units included in the light emitting unit group is shifted in the opposite direction to the second direction with respect to the optical axis of the focusing lens.

2. The light-emitting unit group includes a plurality of light-emitting unit groups each having a different average value of the optical path length between the plurality of light-emitting units included in the light-emitting unit group and the condenser lens, The light emitting device according to claim 1 , wherein the center lines corresponding to the plurality of light emitting unit groups are offset from the optical axis by amounts different from one another.

3. the plurality of light-emitting unit groups include a first light-emitting unit group and a second light-emitting unit group; 3. The light emitting device according to claim 2, wherein the polarization plane of the light contained in the array corresponding to the plurality of light emitting units included in the first light emitting unit group and the polarization plane of the light contained in the array corresponding to the second light emitting unit group are orthogonal to each other.

4. 4. The light emitting device according to claim 1, wherein the group of light emitting units includes the plurality of light emitting units arranged in an array.

5. 5. The light emitting device according to claim 1, wherein the plurality of light emitting units included in the light emitting unit group are arranged to be shifted from one another in the second direction.

6. A light emitting device according to any one of claims 1 to 5, comprising an optical system that shifts a plurality of light beams output from the plurality of light emitting units included in the light emitting unit group and traveling along an optical path perpendicular to the second direction in the opposite direction to the second direction, and outputs them in a direction perpendicular to the second direction.

7. The light emitting device according to claim 6 , wherein the optical system includes an optical component having a plurality of reflecting surfaces.

8. The light emitting device according to claim 6 , wherein the optical system includes an optical component having a plurality of refractive surfaces.

9. The light emitting device according to claim 6 , wherein the optical system includes a plurality of optical components each having a reflective surface.

10. When the width of the beam of light output from the plurality of light-emitting units included in the light-emitting unit group is w, the deviation of the center line corresponding to the light-emitting unit group from the optical axis of the focusing lens is 0.25w or more and w or less. A light-emitting device according to any one of claims 1 to 9.

11. 11. The light emitting device according to claim 1, wherein the wavelength of light output from the light emitting unit is 400 nm or more and 550 nm or less.

12. A light source device comprising the light emitting device according to any one of claims 1 to 11.

Images