A light-emitting device improves the beam quality of emission light from a single emitter light source in the slow-axis direction, and includes a light source 10 having a single emitter and a beam shaping module that splits the emission light from the light source into to a plurality of split-lights in the slow-axis direction, and shapes the split-lights as a shaped-beam arrayed in the fast-axis direction, and outputs the shaped-beam.

CROSS REFERENCE TO RELATED APPLICATIONS

This application relates to, and claims priority from JP 2017-237374 filed Dec. 12, 2017, the entire contents of which are incorporated herein by reference.

FIGURE SELECTED FOR PUBLICATION

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a light-emitting device that shapes the lights emitted from the light source and outputs the shaped light.

Description of the Related Art

The light-emitting device is used to guide the converged light into the light receiving device such as an optical fiber to obtain a high-power output. Such a light-emitting device is adopting the method to converge the emitted light from the light emission diode (LED) or a semiconductor laser as a light source by using an optical element such as a lens or a prism.

In addition, with regard to the emission-light such as semiconductor laser, an improvement of the beam quality of the slow-axis, of which beam quality is lower than the beam quality of the fast-axis, is under study. For example, the method, in which the emission light of the semiconductor laser array in which a plurality of the light-emitting areas (emitters) in the slow-axis (horizontal) direction are paralleled light is split by the optical element in the slow-axis direction, and the split laser lights are paralleled in the fast-axis direction, is proposed.

RELATED PRIOR ART DOCUMENTS

Patent Document

Patent Document 1: JP Patent Published 2003-279885

Aspects and Summary of the Invention

Objects to be Solved

Even when a light source for the single emitter is used, it is desirable that the beam quality in the slow-axis direction is improved. For example, when the emission light of the high-power semiconductor laser having the single emitter is coupled to the optical fiber having a small core and a low numerical aperture (NA), the beam quality in the fast-axis (vertical) direction is not concerned, but the beam quality in the slow-axis direction is low (poor), so that the emission light cannot be coupled in a high-efficiency.

Considering the above issues, the purpose of the present invention is to provide a light-emitting device that improves the beam quality in the slow-axis direction of the emission light from a single emitter light source.

Means for Solving the Problem

According to the aspect of the present invention, the present invention provides a light-emitting device that comprises a light source having a single emitter and a beam shaping module that splits the emission light from the light source to a plurality of split-lights in the slow-axis (horizontal) direction, shapes the plurality of split-lights to create the shaped-beam that are arrayed in the fast-axis (vertical) direction, and outputs such a shaped-beam.

Effect of the Invention

According to the aspect of the present invention, the present invention provides the light-emitting device that improves the beam quality of the emission light from the single emitter light source in the slow-axis (horizontal) direction is provided.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Those of skill in the art have great skill, having advanced training understand all the conventionally known circuits, elements, and arrangements and understand that any circuit, element, or related computational type system includes an input device for receiving data (of any type), an output device for outputting data in any tangible form (e.g. single, data, display, light, etc., any suitable memory for storing data as well as computer code, and for executing the same.

Although only a few embodiments have been disclosed in detail above, other embodiments are possible and the inventors intend these to be encompassed within this specification. The specification describes certain technological solutions to solve the technical problems that are described expressly and inherently in this application. This disclosure describes embodiments, and the claims are intended to cover any modification or alternative or generalization of these embodiments which might be predictable to a person having ordinary skill in the art.

Referring to all the figures (FIGS.), the inventors set forth the Embodiments of the present invention. Referring to FIGS., the same or similar element has the same or similar sign. However, it must be paid attention that FIGS. are schematic. In addition, hereinafter, the aspect of the Embodiment is an example to specify the technology aspect of the present invention and the structure and the arrangement of the components are not limited to the aspect of the Embodiment. The aspect of the Embodiment of the present invention can be modified in a variety of aspects within the scope of claimed claims of the present invention.

Referring toFIG. 1, according to the aspect of the Embodiment 1 of the present invention, the light-emitting device1comprises a light source10having a single emitter and a beam shaping module30that splits the emission light L10from the light source10to a plurality of split-lights L11-L1nin the slow-axis direction, shapes the split-lights L11-L1nas the shaped-beam L20arrayed in the fast-axis direction, and outputs such a shaped-beam (n is an integer at least 2).

Referring toFIG. 1, the light-emitting device1further comprises a collimator20that collimates the emission light L10of the light source10in the fast-axis direction of the emission light L10and the slow-axis direction thereof. Specifically, the emission light L10that is collimated in the fast-axis direction and the slow-axis direction is guided *(induced) into the beam shaping module30, and the collimator20, referring toFIG. 1, comprises the F-axis collimator lens21that collimates the emission light L10in the fast-axis direction and the S-axis collimator lens22that collimates the emission light L10in the slow-axis direction. Referring toFIG. 1, the F-axis collimator lens21is in-place right near the light source10and the S-axis collimator lens22is in-place in a constant interval from the F-axis collimator lens21.

Specifically, the emission light L10is collimated by the F-axis collimator lens21followed by being collimated by the S-axis collimator lens22. The beam shaping module30outputs the shaped-beam L20that is the shaped collimated emission light L10.

The shaped-beam L20output from the beam shaping module30is converged by the light converging device3and then, guided to the light receiving device2. The light receiving device2is e.g., an optical fiber, and the shaped-beam L20is converged into the core of the optical fiber. The converging device3is e.g., a converging lens.

For example, the light source10is the single emitter high-power semiconductor laser. With regard to such as a semiconductor laser having the single emitter, the beam shape of the perpendicular cross-section to the traveling direction of the emission light (hereinafter, called traveling surface) is an ellipse (oval shape). For example, with regard to the emission light from the edge-emitting type single emitter semiconductor laser, the beam thereof largely broadens in the direction in which the emitter size is smaller. Specifically, referring toFIG. 2, the broad-size direction of the emitter area A is a slow-axis direction S and the narrow-size direction of the emitter area A is the fast-axis direction F.

With regard to the emission light L10of the light source10, the beam quality in the slow-axis direction S is lower than in the fast-axis direction F. Specifically, the edge of the beam in the slow-axis direction S is poor (less focused) compared to the fast-axis direction F and as a result, a sharp shape cannot be obtained when converging the light. Therefore, when the emission light L10of the light source10couples as-is with the optical fiber, it is problematic that the coupling efficiency worsens.

Whereas the light-emitting device1, referring toFIG. 1, improves the beam quality in the slow-axis direction S of the emission light L10due to the beam shaping module30. Specifically, the emission light L10is split in the slow-axis direction S in which the beam quality is poor and then, the split-lights L11-L1nare overlapped in the fast-axis direction F. In such a way, the length of the shaped-beam L20in the slow-axis direction S shortens, and as a result, the coupling efficiency improves.

At the same time, the quality of the shaped-beam L20in the fast-axis direction F worsens. Whereas the beam quality in the fast-axis direction F is several ten times better than in the slow-axis direction S, so that a decrease of the coupling efficiency is never concerned.

Hereinafter, the inventor sets forth an operation of the light-emitting device1.

Referring toFIG. 1, the emission light L10emitted from the light source10is first collimated in the fast-axis direction F by the F-axis collimator lens21. The beam quality in the fast-axis direction F is high, so that the interval between the light source10and the F-axis collimator lens21is arbitrary, whereas the narrower the interval is, the smaller the size of the light-emitting device1can be.

The emission light L10of which the beam shape in the traveling surface is broadening in the slow-axis direction S is guided into the S-axis collimator lens22that is in-place in the constant interval from the F-axis collimator lens21, and the emission light L10is collimated in the slow-axis direction S. Then, the emission light L10having a long and thin beam shape in the slow-axis direction S is guided into the beam shaping module30.

The beam shaping module30comprises the light splitting element31and the light-path modifying element32. The light splitting element31divides the emission light L10to a plurality of the split-lights L11˜L1nby modifying the light-axis from the original light-axis thereof relative to the part of the collimated emission light L10. The light-path modifying element32propagates the divided lights L11˜L1nrespectively in the different light-path. In addition, the light-path modifying element32comprises respective light paths of the split-lights L11˜L1nso that the split-lights L11˜L1nare arrayed in the fast-axis direction F.

The light splitting element31splits the emission light L10so as to change the light-axis of at least one split-light of the split-lights L11˜L1n. Accordingly, for example, the split-lights L11˜L1ntravel (propagate) in parallel to and in split from each other. Or the emission light L10is split so that the light-axis of the beam of the part passing the light splitting element31and the light-axis of the beam of the part not passing cross with a constant angle so that the split-lights L11˜L1ntravel respectively in the different direction from each other.

The light splitting element31may include e.g., a laser window, a beam splitter (e.g., splitter), an optical mirror, a prism and so forth. In addition, an optical mirror, a prism and so forth is applicable to the light-path modifying element32.

Referring toFIG. 3, 4, the laser splitter (window)310as the light splitting element31is in-place tilting to the light-axis and the light-path modifying element32is the optical mirror320. Specifically, the tilting laser splitter (window)310splits the emission light L10two lights consisting of the split-light L11and the split-light L12in the slow-axis direction S. In such a way, the laser splitter310is applied to the light splitting element31, so that the light-axis of the split-light L11that transmits the laser splitter310changes (shifts) from the light-axis of the emission light L10before splitting. On the other hand, the light-axis of the split-light L12does not change from the emission light L10before splitting.

Now, the light path of the split-light L11is modified by the optical mirror320, and the split-light L11and the split-light L12overlap and are arrayed in the fast-axis direction F.

Referring toFIG. 5, for example, the beam shaping module30splits the emission light L10, of which the traveling surface has the long and thin beam shape in the slow-axis direction S, is split in the slow-axis direction S. Then, the shaped-beam L20is obtained, wherein the split-light L11of the emission light L10and the split-light L12thereof overlap in the fast-axis direction F.

In addition, referring toFIG. 6, the beam shape of the traveling surface is obtained by dividing the emission light L10equally to two portions. Specifically, the light splitting element31is in-place at the location where a half of the beam along the slow-axis direction passes through. For example, with respect to the half of the beam passing through the laser splitter310, the laser splitter310is in-place with the shifting angle from the light-axis of the beam of which the light-axis is not passing the laser splitter310.

Regardless of splitting the emission light L10equally to two, the shaped-beam L20of which the shape of the traveling surface is a rectangular shape is obtained by that the beam shaping module30splits the emission light L10equally as the respective lengths of the split-lights in the slow-axis direction S are the same.

In addition, when the laser splitter310is applied to the light splitting element31, the smaller angle between the incidence surface of the laser splitter, to which the emission light L10is incident, and the light-axis of the emission light L10is, the larger the shift amount of the light-axis is. In addition, the example in which the split-lights are overlapped without a gap in the fast-axis direction F is set forth, a gap can be set up between the split-lights along the fast-axis direction F.

As set forth above, according to the light-emitting device1, the split-lights L11˜L1nobtained by splitting the emission light L10along the slow-axis direction S, in which the beam quality is poor, are overlapped and arrayed in the fast-axis direction F. In such a way, the poor quality in the slow-axis direction S is dispersed in the fast-axis direction F, so that the beam quality in the slow-axis direction S improves. As a result, the shaped-beam L20, in which the beam quality improves, is obtained.

In addition, according to the light-emitting device1, the beam shaping module30made of the inexpensive optical elements such as a laser splitter, an optical mirror and a prism improves the beam quality in the slow-axis direction S. Specifically, the shaped-beam L20, in which the beam quality improves despite the low cost, is obtained.

FIG. 7Ais illustrating the Embodiment relative to the beam diameter of the converging beam that the light converging device3converges the shaped-beam L20. The horizontal axis is the distance Z in the positive direction, in which the converging beam travels toward the converging spot from the reference point (0 mm) that is an arbitrary location after the converging beam passed the light converging device3. In addition,FIG. 7Ais illustrating the Embodiment relative to the beam diameter of the converging beam overlapped in the fast-axis direction F after the beam shaping module30split the emission light L10to two in the slow-axis direction S by almost the same strength.

In addition,FIG. 7Bis illustrating the beam diameter of the converging beam of the comparative Embodiment, in which the beam shaping module30does not conduct the beam shaping.FIG. 7Bis illustrating the beam diameter of the converging beam when the light converging device3is in-place at the same location as the case inFIG. 7Ain the state in which the beam shaping module30is not in-place.

ComparingFIG. 7AandFIG. 7B, the converging diameter where the beam diameter of the converging beam is thinnest after converging is approximately half of the comparison Embodiment by conducting a beam shaping with the beam shaping module30. In addition, M-square value is approximately half of the M-square value of the comparison Embodiment. In such a way, the light-emitting device1, according to the aspect of the Embodiment, improves the beam quality.

As set forth above, according to the aspect of the Embodiment of the present invention, the light-emitting device1splits the emission light L10emitted from the light source10having the single emitter to a plurality of split-lights in the slow-axis direction S and layers and arrays such split-lights in the fast-axis direction F. As a result, with respect to the emission light L10, the beam quality thereof in the slow-axis direction S improves and the shaped-beam L20converges into the smaller diameter with the high-quality thereof. Accordingly, for example, the emission light L10couples with an optical fiber having a small diameter and a low NA in a high-efficiency.

In addition, with regard to the light-emitting device1, the beam diameter in the slow-axis direction S is shorter, for example, as illustrated in the comparison Embodiment referring toFIG. 8, a decrease of the coupling efficiency due to the side-drop of the edge of the beam L outside the light receiving device2is prevented.

In addition, the beam shape of the shaped-beam L20also depends on the collimator20. Therefore, according to the beam quality of the light source10and the specification of the light receiving device2, the property and arrangement of the collimator lens should be examined.

According to the above Embodiment, the beam of the emission light L10is equally split to two. Whereas, the beam shaping module30may split the emission light L10to provide a plurality of split-light of which at least one split-light has the different length in the slow-axis direction S from other split-lights.

Referring toFIG. 9, for example, the beam quality in the slow-axis direction S improves by just splitting the emission light L10without particularly splitting equally to two lights. According to the Embodiment referring toFIG. 9, the ratio of the split-light L11that passes through the laser splitter310uses as the light splitting element31, is less than half. Accordingly, referring toFIG. 10, the beam shape of traveling surface of the combined shaped-beam L20of the split-light L11and the split-light L12in the fast-axis direction F is not a rectangular shape.

When splitting the emission light L10equally into two, the edge of the light splitting element31locates at the center of the beam of which the strength of the emission light L10is highest. Therefore, when a part of the emission light L10is dispersed or absorbed at the edge of the light splitting element31, a decreasing rate of the strength of the emission light L10might be big.

On the other hand, referring toFIG. 9, given the edge location of the light splitting element31shifts from the center of the beam, the decreasing rate of the strength of the emission light L10is suppressed.

As set forth above, the emission light L10of the light source10is split to two, the emission light L10can be split to more than 3 using a plurality of the light splitting elements31. For example, referring toFIG. 11, the first laser splitter310aand the second laser splitter310bsplit the emission light L10to3, i.e., the split-light L11, the split-light L12and the split-light L13.

Accordingly, referring toFIG. 12, the shaped-beam L20, of which the split-light L11—the split-light L13are overlapped thrice in the fast-axis direction F, is obtained. As a result, the beam quality in the slow-axis direction S improves three times.

An optical element other than the laser splitter is applied to the light splitting element31. For example, a right-angle prism splits the emission light L10.

Specifically, referring toFIG. 13, a part of the emission light L10, as a split-light L11, is guided to the second prism313for retroreflection by the first prism312. The split-light L11is retroreflected (folding back) inside the second prism313and then guided to the third prism (mirror)314. Now, the split-light L11reflected at the third prism (mirror)314and the split-light L12, which is another part of the emission light L10, that transmits the third prism (mirror)314overlap in the fast-axis direction F.

Referring toFIG. 14, the light-emitting device1according to the aspect of the Embodiment 2 of the present invention comprises the first light source10aand the second light source10b, and each of which polarization direction differs from each other.

The first emission light L10afrom the first light source10ais collimated by the first F-axis collimator lens21afollowed in the fast-axis direction F followed by being collimated by the first S-axis collimator lens22ain the slow-axis direction S. Then, the collimated first emission light L10ais guided to the beam shaping module30. The second emission light L10bfrom the second light source10bis collimated by the second F-axis collimator lens21bin the fast-axis direction F followed by being collimated by the second S-axis collimator lens22bin the slow-axis direction S. Then, the collimated second emission light L10bis guided to the beam shaping module30.

The beam shaping module30according to the aspect of the Embodiment 2 carries out beam shaping of the first emission light L10aof the first light source10aby the first light splitting element31aand the first light-path modifying element32a. Specifically, the first shaped-beam L20ais obtained by overlapping the split-lights L11a˜L1nain the fast-axis direction F following splitting the first emission light L10ato a plurality of split-lights L11a˜L1nain the slow-axis direction S.

As well as, the beam shaping module30according to the aspect of the Embodiment 2 carries out beam shaping of the second emission light L10bof the second light source10bby the second light splitting element31band the second light-path modifying element32b. Specifically, the first shaped-beam L20bis obtained by overlapping the split-lights L11b-L1nbin the fast-axis direction F following splitting the first emission light L10bto a plurality of split-lights L11b˜L1nbin the slow-axis direction S.

Referring toFIG. 14, the beam shaping module30combines the first shape beam L20aand the second shaped-beam L20bof which the light-path is modified by the optical mirror33by the polarization beam splitter34. In such a way, the first emission light L10afrom the first light source10aand the second emission light L10bfrom the second light source10bare polarized and combined and then, the shaped-beam L20, of which beam quality in the slow-axis direction S is improved, is output from the beam shaping module30.

In addition, a beam splitter may be inserted between the polarization beam splitter34and the first light-path modifying element32aor the second light-path modifying element32b. Each beam shape of the first shaped-beam L20aand the second shaped-beam L20bcan be confirmed by monitoring the beam split by the beam splitter.

According to the aspect set forth above, the number of the light sources10, of which polarization direction differs from each other, is two, but the number of the light sources10can be larger than 3. With respect to the light-emitting device1according to the aspect of the Embodiment 2, a plurality of shaped-beams of which the respective emission lights from a plurality of light source, of which each polarization direction differs from each other, is polarized and combined and then, the shaped-beam L20of which the beam quality is improved in the slow-axis direction S is obtained. In addition, a plurality of shaped-beams is polarized and combined to increase the strength of the shaped-beam L20. Other aspects are the same as the Embodiment 1 and the duplicate description is skipped.

Other Embodiments

As set forth above, the present invention is described according to the aspect of the Embodiments, but it should not be understood that any parts, description and FIGS., of the present disclosure may limit the present invention. According to the present disclosure, a person skilled in the art can realize that a variety of the alternative Embodiment and applicable technology are clear.

For example, according to the aspect of the Embodiment 1 set forth above, the number of the beam shaping module30is one. However, for example, referring toFIG. 15, a plurality of beam shaping modules30can be multiplied and connected. Referring toFIG. 15, with respect to the light-emitting device1, the shape beam L20output from each beam shaping module30is guided to the beam shaping module30in the next position. The number of connected beams shaping modules30is arbitrarily set up depending on the beam quality of the emission light L10from the light source10and a required diameter for the shaped-beam L20or the specification of the light receiving device2.

In addition, as set forth above, the light emitting device1comprises the collimator20that collimates the emission light L10from the light source10. However, when the light source10that emits the collimated emission light L10is used, the collimator20can be eliminated.

In addition, the light emitting device1according to the aspect of the Embodiment is applicable to a variety of light sources10of which the beam quality in the slow-axis direction S is relatively poor compared to the beam quality in the fast-axis direction F. Specifically, for example, a solid laser other than the semiconductor laser light source can be applied to the light source10.

In addition, according to the aspect of the Embodiment as set forth above, whereas the emission light L10is coupled to the light receiving device2after converging lights by the converging device3, the light emitting device1can be applied to the other use. For example, the aspect of present invention is also applicable to the use in which the shaped-beam L20from the beam shaping module30is directly irradiated to a target.

Needless to say, the present invention may include a variety of Embodiments that are not described here.

REFERENCE OF SIGNS

Also, the inventors intend that only those claims which use both ‘means’ and ‘for’ in combination as the words “means for” are intended to be interpreted under 35 USC 112, sixth paragraph/(f). Moreover, no limitations from the specification are intended to be read into any claims, unless those limitations are expressly included in the claims.