JP2021086862A - Multi-chip package, projector - Google Patents

Abstract

To realize a multi-chip package that can reduce speckle.SOLUTION: The multi-chip package (1) comprises a plurality of semiconductor laser chips (4), a plurality of beam splitters (5, 6) comprising passive elements that correspond to each of the plurality of semiconductor laser chips (4) and split the laser beams emitted from each of the plurality of semiconductor laser chips (4) into a plurality of sub-beams, and one or more reflectors (7) that reflect the plurality of sub-beams to the outside of the multi-chip package (1).SELECTED DRAWING: Figure 1

Description

The present invention relates to a multi-chip package and a projector provided with the multi-chip package.

Various multi-chip packages have been known conventionally, and Patent Documents 1 to 4 are mentioned as an example.

The light emitting device of Patent Document 1 includes a substrate, a lens array having a plurality of lens portions, and a plurality of semiconductor laser elements arranged on the substrate.

The laser diode device of Patent Document 2 includes a deflection element, and the deflection element deflects a laser emitted from a laser diode chip toward a cover member.

The system of Patent Document 3 is a system for reducing speckle, and combines a plurality of lasers emitted from a plurality of laser light sources.

The device of Patent Document 4 is a device for reducing speckle, and includes a microscanner and a holographic diffuser. The microscanner is composed of active elements, and the refractive index changes depending on the applied voltage.

JP-A-2016-219779 U.S. Patent Application Publication No. 2013/0272329 International Patent Application Publication No. 2018/141407 International Patent Application Publication No. 2012/136970

Lasers have the advantages of high brightness, long life, and high color gamut obtained by superimposing multiple lasers with a narrow band spectrum. Therefore, the laser is used as a light source of a high-power projector or the like. On the other hand, when a laser is used as a light source for a projector, there may be a problem that a perceptible speckle is generated in the projected image.

Therefore, in order to reduce speckle, an active element such as a diffuser that vibrates mechanically is used. However, the active element has a shorter average time to failure than other components (laser light source, etc.) included in the projector. In addition, the diffuser causes light loss, so that the brightness is lowered and heat is generated.

Neither the light emitting device of Patent Document 1 nor the laser diode device of Patent Document 2 is provided with an optical element for reducing speckle, and the laser beam emitted from each laser is split into two or more beams. Does not have a beam splitter.

The system of Patent Document 3 is difficult to apply to a multi-chip package. Further, in the system of Patent Document 3, an optical member (microlens array or the like) is movable. Therefore, the system of Patent Document 3 has problems in compactness, robustness, energy efficiency, sound, and the like.

The device of Patent Document 4 is difficult to apply to a multi-chip package. Further, the apparatus of Patent Document 4 uses an active element in order to reduce speckle.

One aspect of the present invention is to realize a multi-chip package capable of reducing speckle by using a passive element.

(1) In order to solve the above problems, the multi-chip package according to one aspect of the present disclosure corresponds to a plurality of semiconductor laser chips and each of the plurality of semiconductor laser chips, and the plurality of semiconductor laser chips. A plurality of beam dividing parts composed of passive elements that divide the laser beam emitted from each into a plurality of subbeams, and one or more reflecting parts that reflect the plurality of subbeams to the outside of the multi-chip package. To be equipped.
(2) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration of (1) above, each of the plurality of beam splitting portions is one or more beams that split the laser beam into the plurality of subbeams. It includes a splitter and one or more reflectors that reflect at least one of the plurality of subbeams split by the one or more beam splitters.
(3) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration of (2) above, the one or more reflectors include at least a first reflector, a second reflector, and a third reflector. The one or more beam splitters include at least a first beam splitter, and the one or more reflecting portions are at least the first reflector, the second reflector, and the first beam splitter among the plurality of subbeams. The sub-beam circulating in the configured circulating optical path is reflected to the outside of the multi-chip package.
(4) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration of (2) or (3) above, one or more beam splitters are polarization-dependent beam splitters.
(5) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration of (1) above, at least one beam dividing portion among the plurality of beam dividing portions uses the laser beam as the plurality of subbeams. It is provided with a beam dividing function unit that divides the beam into the above, and a base unit that includes the beam dividing function unit inside or on the surface.
(6) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration according to any one of (1) to (5) above, the plurality of sub-beams emitted to the outside of the multi-chip package are parallelized. It is provided with one or more collimating portions that promote.
(7) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration of (6) above, the one or more collimating portions are located between the plurality of semiconductor laser chips and the plurality of beam dividing portions. It is a lens provided in.
(8) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration of (6), the one or more collimating portions are located between the plurality of semiconductor laser chips and the plurality of beam dividing portions. It is a curved mirror provided in.
(9) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration of (6) above, the one or more collimating portions are provided on the wake side of the one or more reflecting portions.
(10) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration according to any one of (6) to (9) above, the one or more collimating portions include a plurality of collimating portions, and the plurality of collimating portions are included. The collimated parts of are irregularly arranged.
(11) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration according to any one of (1) to (10), the one or more reflecting portions are at least one of the plurality of subbeams. The subbeam is reflected in a different direction from the other subbeams.
(12) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration according to any one of (1) to (11), the one or more reflecting portions are at least one of the plurality of subbeams. The subbeam is emitted in a direction different from that of other subbeams.
(13) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration according to any one of (1) to (12) above, light transmission having a non-uniform thickness in the optical path of the plurality of subbeams. It has a sex optical path length change part.
(14) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration according to any one of (1) to (13) above, the one or more reflecting portions are two laser beams incident from different directions. Has at least two laser reflecting surfaces that intersect.
(15) Further, in addition to the configuration according to any one of (1) to (14), the multi-chip package according to one aspect of the present disclosure includes at least one semiconductor laser chip among the plurality of semiconductor laser chips and another. Semiconductor laser chips have different speed axis directions.
(16) Further, the multi-chip package according to one aspect of the present disclosure includes a polarized rotator in the circulating optical path in addition to the configuration of (3).
(17) Further, in the multi-chip package according to one aspect of the present disclosure, in addition to the configuration of (5) above, the beam dividing function portion is a dielectric or one or more metal reflective films, and the substrate portion is glass. is there.
(18) Further, the projector according to one aspect of the present disclosure includes the multi-chip package according to any one of (1) to (17) above.

FIG. 1 is a schematic view of a multi-chip package according to the present embodiment, the upper view is a top view, and the lower view is a side view. FIG. 2 is a schematic diagram illustrating a beam split having a simple configuration. It is a schematic diagram explaining the cavity type beam split, the left figure shows the case where the beam splitter 5 is a polarization independent beam splitter, and the right figure shows the case where the beam splitter 5 is a polarization dependent beam splitter. It is a schematic view for demonstrating the lens provided on the upper part of a cover, the upper figure is a top view, and the lower figure is a side view. It is a schematic view for demonstrating the lens provided on the upper part of a cover, the upper figure is a top view, and the lower figure is a side view. It is a schematic view for demonstrating the lens provided on the upper part of a cover, the upper figure is a top view, and the lower figure is a side view. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the lens included in the multi-chip package which concerns on another embodiment. It is the schematic of the multi-chip package which concerns on another embodiment, the upper figure is a top view, and the lower figure is a side view. It is a top view of the multi-chip package which concerns on other embodiments. It is a schematic view of the multi-chip package according to another embodiment, the upper figure is a top view, and the lower figure is a view showing how a laser beam is parallelized by a curved lens. It is a side view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is the schematic of the multi-chip package which concerns on other embodiment. It is a schematic view of the multi-chip package according to another embodiment, the upper figure is a top view, and the lower figure shows how a laser beam is irradiated from a semiconductor laser chip. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a top view of the multi-chip package which concerns on other embodiments. It is a perspective view of the multi-chip package which concerns on another embodiment. It is the schematic of the projector which concerns on this embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The embodiments described below are an example as means for realizing the present disclosure, and should be appropriately modified or changed depending on the configuration of the device to which the present disclosure is applied or various conditions, and the present disclosure is the following embodiments. It is not limited to. Further, in the drawings described below, the same or functionally similar components are designated by the same reference numerals, and the repeated description thereof will be omitted. Further, each drawing is shown for easy understanding when referred to together with the following description, and is not necessarily drawn at a certain ratio of scale.

[Example of application of multi-chip package]
In recent years, a high-power multi-chip package has been used as a light source instead of the To-CAN package. This is because the multi-chip package is compact and it is easy to realize cost reduction. The multi-chip package is ideally designed so that the speckle is reduced behind the light source by reducing the coherence characteristics of the multi-chip package. This design eliminates the need to provide an element that reduces speckle in the optical path behind the light source, and makes it easier to use a passive element that does not easily affect the cost and life of the projector.

For convenience of explanation, first, a configuration example of the projector 200 provided with the multi-chip package 1 (described later) according to the present disclosure will be described. FIG. 30 is a schematic view of the projector 200 according to the present disclosure.

〔projector〕
The projector 200 includes a multi-chip package 1, a beam forming optical system 201, a homogenizer 202, a spatial light modulation unit 203, a projection optical system 204, and a screen 205. Known techniques may be used for the beam forming optical system 201, the homogenizer 202, the spatial light modulation unit 203, the projection optical system 204, and the screen 205.

The projector 200 includes a multi-chip package 1 (described later) according to the first embodiment. The projector 200 may include another multi-chip package according to the present disclosure instead of the multi-chip package 1. Hereinafter, the projector 200 will be described as including the multi-chip package 1. The laser beam emitted from the multi-chip package 1 is incident on the beam forming optical system 201.

The beam forming optical system 201 is used to obtain the laser beam required for projection on the screen 205. The beam forming optical system 201 refracts the laser beam emitted from the multi-chip package 1 and focuses it on the homogenizer 202. The beam forming optical system 201 may be composed of, for example, one or more lenses.

The homogenizer 202 forms the laser beam incident from the beam forming optical system 201 into a laser beam having a uniform light intensity distribution. As the homogenizer 202, for example, a method using a fly-eye lens in which single lenses are arranged in an array, a method using an aspherical lens, or a method using a diffractive optical element may be adopted. The homogenizer 202 may also include a diffuser or an optical pipe.

The spatial and temporal coherence characteristics of the laser beam incident on the homogenizer 202 are preferably lower than in conventional multi-chip packages in order to reduce speckle. To this end, the projector 200 includes a multi-chip package 1 according to an aspect of the present invention.

The spatial light modulation unit 203 changes (modulates) the laser beam by electrically controlling the spatial distribution (amplitude, phase, polarization, etc.) of the laser beam incident from the homogenizer 202.

The projection optical system 204 synthesizes a laser beam modulated by the spatial light modulation unit 203 and projects it on the screen 205.

The projector 200 includes a multi-chip package 1. As will be described in detail later, the multi-chip package 1 variously changes the angle, spatial spread, and / or optical path length of the laser beam. As a result, the projector 200 can reduce the speckle.

The multi-chip package 1 includes a plurality of semiconductor laser chips 4, and the plurality of semiconductor laser chips 4 are separated from each other. Therefore, the heat sink (sub-mount 3) according to the present disclosure can be made simpler and smaller than the heat sink used in the existing multi-chip package.

On the other hand, when the diffuser is provided inside the multi-chip package, the angle, spatial spread, and / or optical path length of the laser beam can be changed in various ways, but the light loss and stray light are unacceptable. Can occur.

The projector 200 uses the multi-chip package 1 as a light source. The multi-chip package 1 can emit a high-intensity laser beam with reduced speckle and low light loss. Therefore, the projector 200 can also enjoy the same effect as that obtained by the multi-chip package 1.

Hereinafter, the multi-chip package according to each embodiment will be described.

[Embodiment 1]
FIG. 1 is a schematic view of the multi-chip package 1 according to the first embodiment, the upper view is a top view, and the lower view is a side view. The multi-chip package 1 is used, for example, as a light source for the projector 200.

The multi-chip package 1 includes a package 2, a plurality of submounts 3, a plurality of semiconductor laser chips 4, a plurality of beam splitters 5, a plurality of folding mirrors 6 (reflectors), a plurality of angle mirrors 7 (reflectors), and a cover 8. To be equipped.

In FIG. 1, the multi-chip package 1 includes a submount 3, a semiconductor laser chip 4, a beam splitter 5, and a folding mirror 6 as one set, for a total of 16 sets. Further, the multi-chip package 1 includes two angle mirrors 7. Eight sets of submounts 3, semiconductor laser chips 4, beam splitters 5, and folding mirrors 6 correspond to one angle mirror 7.

Note that FIG. 1 is an example, and the number of each of the above-mentioned members included in the multi-chip package 1 is not limited to a specific number.

Further, each of the beam splitter 5 and the folding mirror 6 may be collectively referred to as a “beam splitting portion”. Similarly, in the second embodiment described later, one or more optical elements arranged between the semiconductor laser chip 4 and the angle mirror 7 (or the curved mirror 37 in the third embodiment) are collectively referred to as a “beam dividing unit”. May be called. This beam dividing portion is composed of a passive element.

Package 2 is composed of a substrate 2a and a side wall 2b. The substrate 2a supports a plurality of submounts 3, a plurality of beam splitters 5, a plurality of folding mirrors 6, and a plurality of angle mirrors 7. The side wall 2b surrounds the substrate 2a. Package 2 is preferably made of a highly thermally conductive material, tough and hard to break. The multi-chip package 1 is sealed by a substrate 2a, a side wall 2b, and a cover 8. The substrate 2a and the side wall 2b may be made of the same material or different materials.

Each of the plurality of submounts 3 is supported by the substrate 2a, and the heat generated by each of the plurality of semiconductor laser chips 4 is transferred to the substrate 2a. The plurality of submounts 3 are formed of, for example, a semiconductor material, a metal, or a semiconductor material and a metal. When the plurality of submounts 3 are made of a semiconductor material, the coefficient of thermal expansion of the plurality of submounts 3 and the coefficient of thermal expansion of the plurality of semiconductor laser chips 4 can be made close to each other. When the plurality of submounts 3 are made of metal, the metal has high heat transfer properties, so that the temperature rise of the plurality of semiconductor laser chips 4 can be suppressed. When the plurality of submounts 3 are formed of the semiconductor material and the metal, the advantages of the semiconductor material and the metal can be utilized.

The plurality of submounts 3 are preferably regularly arranged on the substrate 2a. Each of the plurality of submounts 3 mounts the corresponding semiconductor laser chip 4 among the plurality of semiconductor laser chips 4.

Each of the plurality of semiconductor laser chips 4 is mounted on the corresponding submount 3 of the plurality of submounts 3. Each of the plurality of semiconductor laser chips 4 has a configuration in which a plurality of semiconductor layers including an active layer are laminated. For example, each of the plurality of semiconductor laser chips 4 has at least an n-type clad layer (first clad layer), an active layer, a p-type clad layer (second clad layer), and a p-type contact layer on an n-type semiconductor substrate. It may have a configuration in which they are laminated in this order. Each of the plurality of semiconductor laser chips 4 is supplied with a predetermined injection current to emit a laser beam having a predetermined oscillation wavelength from at least one end face. The oscillation wavelength of the laser beam emitted by each of the plurality of semiconductor laser chips 4 is not particularly limited.

Each of the plurality of beam splitters 5 splits the laser beam emitted from the corresponding semiconductor laser chip 4 among the plurality of semiconductor laser chips 4 into two. A part of the laser beam incident on each of the plurality of beam splitters 5 is reflected, and the other is transmitted. Hereinafter, the divided laser beam may be referred to as a "sub beam".

The subbeam reflected by each of the plurality of beam splitters 5 is incident on the corresponding folding mirror 6 among the plurality of folding mirrors 6. The subbeam transmitted by each of the plurality of beam splitters 5 is incident on the corresponding angle mirror 7 of the two angle mirrors 7. The plurality of beam splitters 5 may be any of a prism type, a flat type, and a wedge substrate type, respectively. Further, the plurality of beam splitters 5 may be either a polarized beam splitter or a non-polarized beam splitter, respectively.

When the plurality of beam splitters 5 are polarizing beam splitters, preferably, the axes of the plurality of beam splitters 5 are tilted by about 45 degrees with respect to the polarization direction of the laser beams incident from each of the plurality of semiconductor laser chips 4. .. As a result, the laser beam incident on each of the plurality of beam splitters 5 is split into two sub-beams having two orthogonally polarized light components having substantially equal outputs.

When the plurality of beam splitters 5 are unpolarized beam splitters, preferably, the plurality of beam splitters 5 have substantially equal outputs of laser beams incident from the corresponding semiconductor laser chips 4 among the plurality of semiconductor laser chips 2. Split into two subbeams. The beam splitter 5 will be described in detail later with reference to FIG. 2 and the like.

Each of the plurality of folded mirrors 6 reflects the incident sub-beam in the direction of the corresponding angle mirror 7 of the two angle mirrors 7. The plurality of folding mirrors 6 are not limited to a specific type as long as they perform the same function.

Each of the two angle mirrors 7 reflects the plurality of incident subbeams in the direction of the cover 8. Specifically, each of the two angle mirrors 7 reflects a plurality of incident sub-beams from the x-axis direction to the z-axis direction (FIG. 1, lower figure). The two angle mirrors 7 are not limited to a specific type as long as they perform the same function.

Each component of the multi-chip package 1 has been described above. The plurality of submounts 3, the plurality of semiconductor laser chips 4, the plurality of beam splitters 5, the plurality of folding mirrors 6, and the plurality of angle mirrors 7 are regularly arranged on the substrate 2a.

The cover 8 is provided on the side wall 2b and seals the space surrounded by the substrate 2a and the side wall 2b. The cover 8 is made of one or more materials that transmit at least a portion of the laser beam. The cover 8 prevents moisture or dust from entering the inside of the multi-chip package 1.

As described above, the multi-chip package 1 includes a submount 3, a semiconductor laser chip 4, a beam splitter 5, and a folding mirror 6 as one set, for a total of 16 sets. The sub-beams emitted to the outside of the multi-chip package 1 via each set are preferably non-parallel to each other. The plurality of beam splitters 5 and / or the plurality of folding mirrors 6 are arranged so that the sub-beams emitted to the outside of the multi-chip package 1 are non-parallel. As a result, the angle, spatial extent, and / or optical path of the light irradiation field can be varied in the rear (downstream side) of the multi-chip package. As a result, the multi-chip package 1 can reduce the speckle on the downstream side thereof.

[Beam Splitter 5]
Hereinafter, the beam splitter 5 will be further described with reference to FIGS. 2 and 3.

FIG. 2 is a schematic diagram illustrating a beam split having a simple configuration. Since the configuration of FIG. 2 is the same as the configuration described with reference to FIG. 1, the description thereof will be omitted here.

FIG. 3 is a schematic view illustrating a cavity-type beam split, the left figure shows a case where the beam splitter 5 is a polarization-independent beam splitter, and the right figure shows a case where the beam splitter 5 is a polarization-dependent beam splitter. Show.

In FIG. 3, the laser beam incident on the beam splitter 5 from the semiconductor laser chip 4 is split into a plurality of subbeams in the beam splitter 5.

Specifically, the laser beam is split into two subbeams in the beam splitter 5 (first and second subbeams). The first subbeam is reflected in the direction of the folded mirror 6a. The second subbeam passes through the beam splitter 5 and is incident on the folded mirror 6b. The second sub-beam is reflected by the folding mirror 6b, the folding mirror 6c, and the folding mirror 6d, and is incident on the beam splitter 5 again.

The second subbeam is further split by the beam splitter 5 into two subbeams (third and fourth subbeams). The third sub-beam reflects in the direction of the folded mirror 6b and circulates in the cavity again. The fourth subbeam passes through the beam splitter 5 and is incident on the folded mirror 6a.

In this way, the plurality of subbeams circulate in the circulating optical path formed by the beam splitter 5 and the plurality of folded mirrors 6. This circulating optical path is called a cavity. The cavity type beam split refers to a method in which a plurality of subbeams are circulated in the cavity and the plurality of subbeams are taken out of the multi-chip package 1 via at least one folded mirror (folded mirror 6a).

The beam splitter 5 may be substantially either a polarization-independent beam splitter or a polarization-dependent beam splitter.

When the beam splitter 5 is a polarization-independent beam splitter, the reflectance and transmittance are appropriately selected. In the case of FIG. 2, the reflectance and the transmittance are preferably about 50%, respectively. In the case of the left figure of FIG. 3, the ratio of the laser beam entering the cavity and the ratio of the laser beam taken out of the cavity each time it circulates in the cavity are adjusted according to the reflectance and the transmittance. ..

When the beam splitter 5 is a polarization-dependent beam splitter, the axis of the beam splitter 5 is preferably oriented at an angle θ with respect to the polarization direction of the incident laser beam. By adjusting the angle θ, the reflectance and transmittance of the beam splitter 5 are determined.

When a polarization-dependent beam splitter is used in a cavity-type beam split (right figure in FIG. 3), a polarization rotator 9 may be provided in the optical path so that the subbeam circulates in the cavity. The polarized rotator 9 determines the proportion of the laser beam taken out of the cavity each time the subbeam circulates in the cavity.

When it is not possible to sufficiently lose the speckle patterns of a plurality of laser beams simply by changing the traveling direction of the laser beam, a configuration is adopted in which the laser beam is divided into a plurality of saw beams having different polarization components. It is preferable to do so. This configuration can reduce speckle more efficiently than splitting the laser beam into a plurality of subbeams having the same polarization component.

In both the simple beam split (FIG. 2) and the cavity beam split (FIG. 3), the plurality of subbeams emitted to the outside of the multi-chip package 1 are preferably non-parallel to each other. .. By changing the angles of the plurality of subbeams in various ways, it is possible to reduce the speckle generated behind the multichip package 1. An optical element can be provided behind the multi-chip package 1 to further reduce speckle.

In the cavity type beam split, the optical path length when the subbeam circulates once in the cavity is preferably longer than the coherence length (lc) of the semiconductor laser chip 4. Multiple subbeams are not coherent to each other. As a result, the intensity pattern generated from each of the plurality of subbeams can be added to an arbitrary region on which the intensity pattern is superimposed, with almost no limitation on the optical element provided behind the multi-chip package 1. Since the emission angles of the plurality of subbeams are different from each other, arbitrary speckle intensity changes do not share with each other.

Similarly, the optical path length difference between the two subbeams divided by the beam split having a simple configuration is preferably longer than the coherence length of the semiconductor laser chip 4. The optical path length is the distance between the emission point of the laser beam of the semiconductor laser chip 4 and the emission point of the laser beam emitted from the multi-chip package 1.

The maximum value of the angle difference between the plurality of subbeams emitted from the multi-chip package 1 is determined by the optical element used behind the multi-chip package 1. It is not preferable that the optical element has an angular difference so that it cannot capture most of the laser beam.

When the laser beam before being incident on the cavity type beam split that easily dissipates energy is not parallelized, even if a lens or the like is provided behind the multi-chip package 1, a plurality of sub-beams emitted from the multi-chip package 1 are provided. Is difficult to parallelize. This is because the two divided subbeams have different optical path lengths and intersect in space. Therefore, when it is necessary to reduce the angle difference between the two divided subbeams, it is preferable to parallelize the laser beam before it is incident on the beam splitter 5. Here, "parallelization" is not limited to making the light completely parallel, but also includes the meaning of making the light closer to parallel. This also applies to other embodiments.

[Lens 10]
Next, the lens 10 provided on the upper part of the cover 8 will be described with reference to FIGS. 4 to 6.

FIG. 4 is a schematic view for explaining the lens 10 provided on the upper portion of the cover 8. The upper view is a top view and the lower view is a side view.

When the cover 8 is simply glass, it is preferable to provide a lens array composed of a plurality of lenses 10 on the upper part of the cover 8. As a result, the efficiency of coupling to an optical element (for example, a homogenizer) provided behind the multi-chip package 1 can be improved.

FIG. 4 shows a state in which 16 lenses 10 are provided on the upper part of the cover 8. Each of the 16 lenses 10 corresponds to two beam splitters 5 adjacent to each other in the x-axis direction or two folding mirrors 6 adjacent to each other in the x-axis direction, and the corresponding angle mirror of the two angle mirrors 7. It is located above 7. As a result, all of the plurality of subbeams pass through any one of the 16 lenses 10.

FIG. 5 is a schematic view for explaining the lens 10 provided on the upper portion of the cover 8, the upper view is a top view, and the lower view is a side view.

FIG. 5 shows a configuration in which 32 lenses 10 are provided on the upper portion of the multi-chip package 11, which is a modification of the multi-chip package 1. The multi-chip package 11 includes four angle mirrors 7a. The 32 lenses 10 correspond to one beam splitter 5 and one folding mirror 6, respectively, and are located above the corresponding angle mirror 7a among the four angle mirrors 7a. As a result, all the sub-beams reflected by the four angle mirrors 7a pass through any one of the 32 lenses 10.

FIG. 6 is a schematic view for explaining the lens 10 provided on the upper portion of the cover 8, the upper view is a top view, and the lower view is a side view. Since the multi-chip package 12 is different from the multi-chip package 11 in that the arrangement of the components is changed, detailed description thereof will be omitted.

With the above configuration, the multi-chip package 1, the multi-chip package 11, and the multi-chip package 12 can all improve the coupling efficiency to the optical element provided at the rear.

The lens 10 may be provided on the lower surface of the cover 8 instead of the upper portion of the cover 8.

[Multi-chip package 15]
FIG. 7 is a top view of the multi-chip package 15 according to the present embodiment, which is a modification of the multi-chip package 1. The multi-chip package 15 differs from the multi-chip package 1 in the following (1) to (3).

(1) Two semiconductor laser chips 4 adjacent to each other in the x-axis direction are separated from each other by a distance Δy in the y-axis direction.

(2) Two beam splitters 5 adjacent to each other in the x-axis direction are separated from each other by a distance Δy in the y-axis direction.

(3) Two folded mirrors 6 adjacent to each other in the x-axis direction are separated from each other by a distance Δy in the y-axis direction.

According to the above (1) to (3), the positions of the plurality of subbeams emitted from the multi-chip package 15 can be variously changed in the y-axis direction. As a result, the multi-chip package 15 can obtain the spatial spread of a plurality of subbeams. As a result, the multi-chip package 15 can reduce the speckle behind the multi-chip package 15.

[Embodiment 2]
FIG. 8 is a top view of the multi-chip package 20 according to the embodiment of the present invention. The multi-chip package 20 differs from the multi-chip package 1 in the following points.

Specifically, the multi-chip package 20 includes a plurality of collimating lenses 16 (collimating portions). The plurality of collimating lenses 16 parallelize the plurality of subbeams. Each of the plurality of collimating lenses 16 is provided in the wake of the plurality of angle mirrors 7. For example, the plurality of collimating lenses 16 are provided on the upper surface of the cover 8 or the lower surface of the cover 8, respectively. The plurality of collimating lenses 16 are regularly arranged. In FIG. 8, the plurality of collimating lenses 16 are arranged in a grid pattern.

Each of the plurality of collimating lenses 16 is provided corresponding to each of the plurality of sub-beams emitted from the multi-chip package 20 to the outside, and parallelizes the plurality of sub-beams. Each of the plurality of subbeams is incident on the vicinity of the lens center position of the corresponding collimating lens 16 among the plurality of collimating lenses 16. The incident positions of the plurality of subbeams can be adjusted, for example, by inclining the folding mirror 6 at an appropriate angle. By tilting the folded mirror 6 in this way, the traveling directions of the plurality of subbeams can be made non-parallel to the Z axis.

The plurality of collimating lenses 16 may have different lens characteristics. The optical path length between the sub-beam incident surface of each of the plurality of collimating lenses 16 and the semiconductor laser chip 4 corresponding to each of the plurality of collimating lenses 16 among the plurality of semiconductor laser chips 4 may be different. Therefore, in order to control the total angle spread of the plurality of subbeams emitted to the outside of the multi-chip package 20, it is preferable that the focal lengths of the plurality of collimating lenses 16 are different.

By providing the above configuration, the multi-chip package 20 can vary the angles, spatial spreads, and / or optical path lengths of the plurality of subbeams. As a result, the multi-chip package 20 can reduce the speckle.

Next, the multi-chip package 21, which is a modification of the multi-chip package 20, will be described with reference to FIG.

FIG. 9 is a top view of a plurality of collimating lenses 16 included in the multi-chip package 21 according to the embodiment of the present invention. In FIG. 9, members other than the plurality of collimating lenses 16 are not shown. The multi-chip package 21 has the same configuration as the multi-chip package 20 except for the following points.

Specifically, in the multi-chip package 21, the collimating lenses 16 are not arranged in a grid pattern but are arranged irregularly. The intersection of the grids is called the grid position. The degree or direction of the positional deviation between the lens center position of each of the plurality of collimating lenses 16 and the corresponding grid positions may be randomly determined. Each of the plurality of subbeams is incident on the vicinity of the lens center position of the corresponding collimating lens 16 among the plurality of collimating lenses 16. The incident positions of the plurality of subbeams can be adjusted, for example, by inclining the folding mirror 6 at an appropriate angle. In this way, the lattice position, the center position of the collimating lens 16, and the beam center position of the sub-beam may be different positions. The multi-chip package 21 is an example.

By providing the above configuration, the multi-chip package 21 can vary the angles, spatial spreads, and / or optical path lengths of the plurality of subbeams. As a result, the multi-chip package 21 can reduce the speckle.

[Embodiment 3]
FIG. 10 is a schematic view of a multi-chip package 30 according to an embodiment of the present invention, with an upper view being a top view and a lower view being a side view. The multi-chip package 30 differs from the multi-chip package 1 in the following points.

Specifically, the multi-chip package 30 includes a plurality of curved mirrors 37 (collimating portions) instead of the two angle mirrors 7. Each of the plurality of curved mirrors 37 emits the corresponding subbeam out of the plurality of subbeams to the outside of the multi-chip package 30, and parallelizes the plurality of subbeams to each other.

The curvature and focal length of each of the plurality of curved mirrors 37 are determined by the optical distance from the corresponding semiconductor laser chip 4. The curvature of the curved mirror 37 that reflects the subbeam that has passed through the beam splitter 5 may be larger than the curvature of the curved mirror 37 that reflects the subbeam that has reflected the beam splitter 5.

The multi-chip package 30 includes a plurality of curved mirrors 37 corresponding to each of the plurality of subbeams. Thereby, the multi-chip package 30 can change the angle, spatial spread, and / or optical path length of the plurality of subbeams in various ways. As a result, the multi-chip package 30 can reduce the speckle.

[Embodiment 4]
FIG. 11 is a top view of the multi-chip package 40 according to the embodiment of the present invention. The multi-chip package 40 differs from the multi-chip package 1 in the following points.

Specifically, the multi-chip package 40 includes a plurality of collimating lenses 41 (collimating portions) for parallelizing the laser beam. Each of the plurality of collimating lenses 41 is provided between the corresponding semiconductor laser chip 4 and the corresponding beam splitter 5.

By providing the above configuration, the multi-chip package 40 can suppress the angular spread of the laser beam incident on the beam splitter 5 as compared with the multi-chip package 1. As a result, the multi-chip package 40 can prevent the situation where the subbeam does not enter the beam splitter 5, the folding mirror 6, or the angle mirror 7.

Further, the multi-chip package 40 can (1) suppress unnecessary stray light, (2) increase the efficiency of the multi-chip package, and (3) miniaturize the optical elements in the multi-chip package 40. It has a further effect.

The optical axis of each of the plurality of collimating lenses 41 may be deviated from the beam center of the corresponding laser beam. As a result, the multi-chip package 40 can increase the angular spread of the plurality of sub-beams emitted from the multi-chip package 40 and further reduce the speckle.

The plurality of collimating lenses 41 can be suitably used for the cavity type beam split for the following reasons.

Specifically, in the cavity type beam split, the sub-beam circulates in the cavity many times, and the optical path becomes long. Therefore, when a plurality of collimating lenses 41 are not used, the angular spread in the cavity may become too large. Therefore, by using a plurality of collimating lenses 41 in the configuration related to the cavity type beam split, it is possible to suppress the angular spread in the cavity.

By providing the multi-chip package 40 with the above configuration, the speckle can be reduced. The configuration relating to the plurality of collimating lenses 41 can also be applied to the multi-chip package according to other embodiments (for example, embodiments 1, 6, 7, 8, 9, 10, 11, 12, 13 and the like). ..

[Embodiment 5]
FIG. 12 is a schematic view of the multi-chip package 50 according to the embodiment of the present invention, the upper view is a top view, and the lower figure shows a state in which a laser beam is parallelized by a curved lens 51 (colimating portion). It is a figure. The multi-chip package 50 differs from the multi-chip package 40 in the following points.

Specifically, the multi-chip package 50 includes a plurality of curved lenses 51 instead of the plurality of collimating lenses 41. Each of the plurality of curved lenses 51 parallelizes the laser beam incident in the y-axis direction in the direction of the beam splitter 5 (x-axis direction). This makes it possible to suppress the angular spread of the laser beam incident on the beam splitter 5. The multi-chip package 41 can prevent the subbeam from incident on the beam splitter 5, the folding mirror 6, or the angle mirror 7.

Further, the multi-chip package 41 can (1) suppress unnecessary stray light, (2) increase the efficiency of the multi-chip package, and (3) miniaturize the optical elements in the multi-chip package 41. It has a further effect.

By providing the multi-chip package 50 with the above configuration, speckle can be reduced. The plurality of curved lenses 51 can also be applied to the multi-chip package according to other embodiments (for example, embodiments 1, 6 to 13).

[Embodiment 6]
FIG. 13 is a side view of the multi-chip package 60 according to the embodiment of the present invention. The multi-chip package 60 differs from the multi-chip package 1 in the following points.

Specifically, the multi-chip package 1 includes an angle mirror 7. In the angle mirror 7, the angle formed by the incident surface on which the subbeam is incident and the substrate 2a is about 45 degrees.

On the other hand, the multi-chip package 60 includes an angle mirror 7b. In the angle mirror 7b, the angle (angle α in FIG. 13) formed by the incident surface on which the subbeam is incident and the substrate 2a is not 45 degrees. As a result, as shown in the sub-beams L1 and L2 in FIG. 13, in the multi-chip package 60, a plurality of sub-beams emitted from the angle mirror 7b to the outside of the multi-chip package 60 can intersect with each other. The angle α may be a different numerical value for each angle mirror 7b. In other words, the angle mirror 7b has at least two laser reflecting surfaces that intersect two laser beams incident from different directions.

By providing the above configuration, the multi-chip package 60 can change the angular spread of the plurality of sub-beams emitted from the multi-chip package 60. As a result, the multi-chip package 60 can reduce the speckle.

FIG. 14 is a top view of the multi-chip package 61 according to the embodiment of the present invention. The multi-chip package 61 differs from the multi-chip package 1 in the following points.

Specifically, the multi-chip package 61 includes a plurality of angle mirrors 7b. The plurality of angle mirrors 7b are provided for each of the plurality of beam splitters 5 and each of the plurality of folding mirrors 6.

Each or at least one of the plurality of angle mirrors 7b is non-parallel to the x-axis. In FIG. 14, the plurality of angle mirrors 7b have angles β with respect to the x-axis. The angle β may be different for each angle mirror 7b.

By providing the above configuration, the multi-chip package 61 can change the angular spread of the plurality of sub-beams emitted from the multi-chip package 61. As a result, the multi-chip package 61 can reduce the speckle.

FIG. 15 is a schematic view of a multi-chip package 62 according to an embodiment of the present invention. The multi-chip package 62 differs from the multi-chip package 1 in the following points.

It is assumed that the semiconductor laser chip 4 emits a laser beam parallel to the x-axis. In this case, in the multi-chip package 1, the angle formed by the laser beam incident surface of the beam splitter 5 and the x-axis is about 45 degrees, and the angle formed by the sub-beam light incident surface of the folding mirror 6 and the x-axis is also about about 45 degrees. It is set to 45 degrees.

On the other hand, in the multi-chip package 62, the angle formed by the laser beam incident surface of the beam splitter 5 and the x-axis is about 45 degrees. However, the angle γ formed by the sub-beam incident surface of the folded mirror 6 and the x-axis is set to be larger than 45 degrees or smaller than 45 degrees.

In the multi-chip package 62, the angle between the x-axis and the sub-beam incident surface of the folding mirror 6 is about 45 degrees, and the angle between the x-axis and the laser beam incident surface of the beam splitter 5 is larger than 45 degrees. Alternatively, it may be set to be smaller than 45 degrees.

In this way, by changing the angle at which the beam splitter 5 and / or the folding mirror 6 is provided, the angles at which the plurality of subbeams are incident on the angle mirror 7 can be changed.

By providing the above configuration, the multi-chip package 62 can change the angular spread of the plurality of sub-beams emitted from the multi-chip package 62. As a result, the multi-chip package 62 can reduce the speckle.

[Embodiment 7]
FIG. 16 is a schematic view of the multi-chip package 70 according to the embodiment of the present invention, the upper view is a top view, and the lower figure shows a state in which a laser beam is irradiated from the semiconductor laser chip 4. The multi-chip package 70 differs from the multi-chip package 1 in the following points.

Specifically, the multi-chip package 70 is provided on the substrate 2a by rotating at least a pair of submounts 3 and a semiconductor laser chip 4 in the multi-chip package 1 by 90 degrees. As a result, in one semiconductor laser chip 4, the fast axis (X2) is along the x-axis, the slow axis (X1) is along the y-axis, and in the other semiconductor laser chip 4, the slow axis (X1) is along the x-axis. , The speed axis (X2) is along the y axis (Fig. 16, right figure). In other words, at least one of the plurality of semiconductor laser chips 4 and the other semiconductor laser chip 4 have different speed axis directions from each other.

By providing the above configuration, the multi-chip package 70 can change the angular spread of the laser beam emitted from the multi-chip package 70. As a result, the multi-chip package 70 can reduce the speckle.

"Rotation by 90 degrees" is an example, and rotation angles such as 30 degrees and 45 degrees may be used.

[Embodiment 8]
FIG. 17 is a top view of the multi-chip package 80 according to the embodiment of the present invention. The multi-chip package 80 differs from the multi-chip package 1 in the following points.

Specifically, the multi-chip package 1 includes a total of 16 sets including a submount 3, a semiconductor laser chip 4, a beam splitter 5, and a folding mirror 6. In the multi-chip package 1, the laser beam emitted from the semiconductor laser chip 4 is split into two sub-beams by the beam splitter 5.

On the other hand, the multi-chip package 80 includes a submount 3, a semiconductor laser chip 4, a folding mirror 6 as a set, and two beam splitters 5 (beam splitter 5a, beam splitter 5b) as a set. A total of 16 sets are provided. In the multi-chip package 80, the laser beam emitted from the semiconductor laser chip 4 is split into three subbeams by the beam splitter 5a and the beam splitter 5b.

In the multi-chip package 80, the laser beam emitted from one semiconductor laser chip 4 is divided into three sub-beams. The reflectance and transmittance of the beam splitter 5a and the beam splitter 5b are set so that the three subbeams have substantially equal outputs to each other. For example, the beam splitter 5a has a transmittance of about 33% and a reflectance of about 67%. The beam splitter 5b has a transmittance of about 50% and a reflectance of about 50%. In this way, the three subbeams are set to have substantially equal outputs to each other, without considering light loss.

The beam splitter 5a and the beam splitter 5b may be either a polarization-independent beam splitter or a polarization-dependent beam splitter which is substantially polarization-independent, or may be a combination of the two. When a polarization-dependent beam splitter is used, the axial direction of the beam splitter may be adjusted to determine the split ratio of the laser beam.

As described above, the multi-chip package 80 can obtain the spatial spread of the sub-beams by increasing the number of sub-beams divided from the laser beams. As a result, the multi-chip package 80 can reduce the speckle.

FIG. 18 is a top view of the multi-chip package 81 according to a modification of the multi-chip package 80. The multi-chip package 81 can be obtained by performing the following (1) and (2) on the multi-chip package 80.

(1) The positions of the beam splitter 5a, the beam splitter 5b, and the folding mirror 6 located in the second and fourth rows in the x-axis direction of the multi-chip package 80 are inverted. Then, the inverted beam splitter 5a, the beam splitter 5b, and the folding mirror 6 are shifted in the y-axis direction.

(2) The semiconductor laser chips 4 located in the second and fourth rows in the x-axis direction of the multi-chip package 80 are shifted in the y-axis direction. The semiconductor laser chip 4 is shifted to a position where the laser beam is incident on the center of the beam splitter 5a.

From the above (1) and (2), the multi-chip package 81 can obtain the spatial spread of the subbeam. As a result, the multi-chip package 81 can reduce the speckle.

FIG. 19 is a top view of the multi-chip package 82 according to a modification of the multi-chip package 80. The multi-chip package 82 can be obtained by performing the following (1) and (2) on the multi-chip package 80.

(1) The positions of the beam splitter 5a, the beam splitter 5b, and the folding mirror 6 located in the second and third rows in the x-axis direction of the multi-chip package 80 are inverted. The positions of the inverted beam splitter 5a, the beam splitter 5b, and the folding mirror 6 are shifted in the y-axis direction.

(2) The semiconductor laser chips 4 located in the second and third rows in the x-axis direction of the multi-chip package 80 are shifted in the y-axis direction. The semiconductor laser chip 4 is shifted to a position where the laser beam is incident on the center of the beam splitter 5a.

By providing the multi-chip package 82 with the above configuration, it is possible to obtain a spatial spread of the subbeam. As a result, the multi-chip package 82 can reduce the speckle.

[Embodiment 9]
FIG. 20 is a top view of the multi-chip package 90 according to the embodiment of the present invention. The multi-chip package 90 differs from the multi-chip package 1 in the following points.

Specifically, the multi-chip package 90 includes a total of 16 sets including one beam splitter 5 and four folding mirrors 6. The laser beam emitted from the semiconductor laser chip 4 is split into two subbeams (first and second subbeams) by the beam splitter 5. The first subbeam passes through the beam splitter 5 and heads toward the angle mirror 7. The second subbeam is reflected by the beam splitter 5, then reflected by the four folding mirrors 6 (folding mirrors 6a to 6d), and then incidents on the beam splitter 5 again.

The second subbeam is further split by the beam splitter 5 into two subbeams (third and fourth subbeams). The third subbeam passes through the beam splitter 5, is then reflected by the four folding mirrors 6 (folding mirrors 6a to 6d), and is incident on the beam splitter 5 again. The fourth subbeam is reflected by the beam splitter 5 and directed toward the angle mirror 7.

As described above, the multi-chip package 90 has a configuration corresponding to a cavity type beam split. As a result, the multi-chip package 90 can make a plurality of sub-beams incident on the angle mirror 7 and emit the plurality of sub-beams to the outside of the multi-chip package 90.

By appropriately adjusting the arrangement of the one beam splitter 5 and the four folding mirrors 6, the optical path (angle) of the subbeam can be slightly changed before and after the subbeam circulates once in the cavity. By changing the angle of the sub-beam, the angle, spatial spread, and / or optical path book of the sub-beam emitted to the outside of the multi-chip package 90 can be changed in various ways. As a result, the multi-chip package 90 can reduce speckle behind the multi-chip package 90.

In reality, the number of circulations of the subbeam circulating in the cavity is limited due to the angular spread of the laser beam emitted from the semiconductor laser chip 4 and the angular spread of the subbeam circulating in the cavity. In order to keep the subbeam in the cavity for as long as possible, the optical path length when circulating once in the cavity is preferably made as short as possible. When the laser beam emitted from the semiconductor laser chip 4 is not parallelized, the number of times the sub-beam circulates in the cavity is about several times.

The reflectance and transmittance of the beam splitter 5 take into consideration the efficiency of the multi-chip package, the reduction rate of speckle, or the requirements required when controlling the stray light (diffused light) emitted from the multi-chip package. You just have to decide. When the reflectance of the beam splitter 5 is high, the number of times the subbeam circulates in the cavity increases, and the speckle tends to decrease. However, the efficiency of multi-chip packages is reduced and a large diffuser may be required. In practice, it is considered that there are few cases where the beam splitter 5 is optimal when the reflectance exceeds 70%.

The beam splitter 5 may be either a polarization-independent beam splitter or a polarization-dependent beam splitter that is substantially polarization-independent. When the beam splitter 5 is a polarization-dependent beam splitter, the first beam split is adjusted by selecting the axial direction of the beam splitter 5 with respect to the polarization direction of the laser beam incident from the semiconductor laser chip 4. Each time the sub-beam circulates in the cavity, the sub-beam is emitted to the outside of the cavity. A polarized rotator (not shown) may be provided in the optical path of the cavity in order to control the sub-beam emitted to the outside of the cavity.

As described above, the multi-chip package 90 includes a cavity type beam split, which can reduce speckle.

FIG. 21 is a top view of the multi-chip package 91 according to the present embodiment, which is a modification of the multi-chip package 90. The multi-chip package 91 differs from the multi-chip package 90 in the following (1) to (3).

(1) Of the plurality of semiconductor laser chips 4, the semiconductor laser chips 4 located in the central two rows in the x-axis direction of the multi-chip package 90 are shifted by a distance Δy'in the y-axis direction.

(2) The beam splitter 5 and the folding mirror 6 corresponding to the semiconductor laser chip 4 shifted by Δy'are also shifted by a distance Δy'in the y-axis direction.

(3) The size of the angle mirror 7, the cover 8, and / or the package 2 is increased as necessary in order to utilize the laser beams emitted from all the semiconductor laser chips 4.

According to the above (1) to (3), the positions of the plurality of subbeams emitted from the multi-chip package 91 can be variously changed in the y-axis direction. As a result, the multi-chip package 91 can further reduce the speckle generated behind the multi-chip package 91.

[Embodiment 10]
FIG. 22 is a top view of the multi-chip package 100 according to the embodiment of the present invention. The multi-chip package 100 is different from the multi-chip package 90 in that it has the cavity configuration shown on the left side of FIG. Since the specific contents have been described with reference to FIG. 3, the description here will be omitted.

By providing the above configuration, the multi-chip package 100 can have a more compact cavity than the multi-chip package 90. As a result, the multi-chip package 100 itself can be miniaturized. Further, the multi-chip package 100 is provided with the above configuration to improve the efficiency of the multi-chip package and reduce the angular spread of the sub beam generated each time the sub beam circulates in the cavity so as to reduce stray light. It can be suppressed.

FIG. 23 is a top view of the multi-chip package 101 according to the present embodiment, which is a modification of the multi-chip package 100. The multi-chip package 101 is the same as the multi-chip package 100 except that the beam splitter 5 and the folding mirror 6 located in the second and fourth rows in the x-axis direction of the multi-chip package 100 are rotated by 180 degrees. It has a configuration.

In FIG. 23, S1 and S2 each indicate the incident positions of the plurality of subbeams incident on the angle mirror 7. By providing the above configuration, the multi-chip package 101 can be separated from S1 and S2 as compared with the multi-chip package 100.

By providing the multi-chip package 101 with the above configuration, it is possible to obtain a spatial spread of the subbeam. As a result, the multi-chip package 101 can reduce the speckle.

[Embodiment 11]
FIG. 24 is a top view of the multi-chip package 110 according to the embodiment of the present invention. The multi-chip package 110 differs from the multi-chip package 100 in the following points.

Specifically, the multi-chip package 110 includes a total of 16 sets including one beam splitter 5 and three folding mirrors 6.

By providing the above configuration, the multi-chip package 110 can have a more compact cavity than the multi-chip package 100. As a result, the multi-chip package itself can be miniaturized. Further, the multi-chip package 110 is provided with the above configuration to improve the efficiency of the multi-chip package and reduce the angular spread of the sub beam generated each time the sub beam circulates in the cavity so as to reduce stray light. It can be suppressed. In the multi-chip package 110, the optical path length when the sub-beam circulates once in the cavity is preferably longer than the coherence length of the semiconductor laser chip 4.

FIG. 25 is a top view of the multi-chip package 111 according to the present embodiment, which is a modification of the multi-chip package 110. The multi-chip package 111 differs from the multi-chip package 110 in the following points.

Specifically, the beam splitter 5 and the folding mirror 6 located in the second and fourth rows in the x-axis direction of the multi-chip package 110 are rotated by 180 degrees. The multi-chip package obtained by the rotation is the multi-chip package 111.

In FIG. 25, S1 and S2 each indicate the incident positions of the plurality of subbeams incident on the angle mirror 7. By providing the above configuration, the multi-chip package 111 can be separated from S1 and S2 as compared with the multi-chip package 110.

By providing the multi-chip package 111 with the above configuration, it is possible to obtain a spatial spread of the subbeam. As a result, the multi-chip package 111 can reduce the speckle.

[Embodiment 12]
FIG. 26 is a top view of the multi-chip package 120 according to the embodiment of the present invention. The multi-chip package 120 differs from the multi-chip package 100 in the following points.

Specifically, the multi-chip package 120 includes a beam splitter 18 instead of the beam splitter 5 and the folding mirror 6 that form the cavity.

The beam splitter 18 is composed of, for example, a beam splitting function unit that divides a laser beam into a plurality of subbeams, and a base unit that includes a beam splitting function unit inside or on the surface.

The substrate portion may be, for example, glass or synthetic resin.

The beam dividing function unit reflects a plurality of sub-beams. The beam dividing function unit is composed of, for example, a dielectric or a reflective film. The reflective film may be, for example, a metal material. The beam dividing function portion may be a thin film having a plurality of layers different from the substrate portion, which is provided on the surface of the substrate portion.

In the multi-chip package 120, the beam dividing function unit functions as a cavity. The beam dividing function unit may totally reflect the sub-beam. The surface of the substrate portion may be coated with the beam dividing function portion. The substrate portion may include a beam dividing function portion inside.

By providing the above configuration, the multi-chip package 120 can be assembled more easily than the multi-chip package 100. Further, when a plurality of subbeams propagate through the beam splitting function portion of the beam splitter 18, the plurality of subbeams have different optical path lengths from each other. This difference in optical path length is amplified by the refractive index of the dielectric material.

By providing the above configuration, the multi-chip package 120 can vary the angles, spatial spreads, and / or optical path lengths of the plurality of subbeams. As a result, the multi-chip package 120 can reduce the speckle.

FIG. 27 is a top view of the multi-chip package 121 according to the present embodiment, which is a modification of the multi-chip package 120. The multi-chip package 121 differs from the multi-chip package 120 in the following points.

Specifically, the beam splitters 18 located in the second and fourth rows in the x-axis direction of the multi-chip package 120 are rotated 180 degrees. The multi-chip package obtained by the rotation is the multi-chip package 121.

In FIG. 27, S1 and S2 show the incident positions of the plurality of subbeams incident on the angle mirror 7, respectively. By providing the above configuration, the multi-chip package 121 can be separated from S1 and S2 from the multi-chip package 120.

By providing the multi-chip package 121 with the above configuration, the speckle can be further reduced.

[Embodiment 13]
FIG. 28 is a top view of the multi-chip package 130 according to the embodiment of the present invention. FIG. 29 is a perspective view of the multi-chip package 130. The multi-chip package 130 differs from the multi-chip package 80 in the following points.

Specifically, the multi-chip package 130 includes two optical path length changing units 19 for changing the optical path length. The two optical path length changing portions 19 are provided above the corresponding angle mirrors 7 of the two angle mirrors 7, respectively.

Each of the two optical path length changing portions 19 has a dielectric formed in a stepped shape, and has a plurality of steps of non-uniform thickness in the z-axis direction. A plurality of sub-beams are incident from the angle mirror 7 at each of the portions having a plurality of stages of thickness. As a result, the difference in the optical path length between the plurality of subbeams changes greatly. As a result, the multi-chip package 130 can reduce the speckle. The optical path length changing unit 19 may be included in the multi-chip package according to another embodiment (for example, the first to eighth embodiments).

The two optical path length changing portions 19 may be provided above the corresponding angle mirror 7 of the two angle mirrors 7 and on the lower surface of the cover 8. Alternatively, the two optical path length changing portions 19 may be provided between the beam splitter 5 and the folding mirror 6 and the angle mirror 7, respectively. Each of the two optical path length changing portions 19 may be formed of a light-transmitting medium having a non-uniform thickness in the optical paths of a plurality of subbeams. The number of optical path length changing portions 19 may be 1 or 3 or more.

[Matters common to each embodiment]
The multi-chip package according to each embodiment has been described above. The numbers of the semiconductor laser chip 4, the beam splitter 5, the folding mirror 6, the angle mirror 7, and the like shown in each figure are examples, and are not limited to the numbers shown in the drawings.

(Example 1) In FIG. 1, 16 sets of a submount 3, a semiconductor laser chip 4, a beam splitter 5, and a folding mirror 6 are shown as one set. However, the number of sets may be 2 sets or 48 sets. The angle mirror 7 may be appropriately provided according to the number of sets thereof.

(Example 2) In the description according to the second embodiment, the multi-chip package 20 is described as including a plurality of collimating lenses 16. However, the multi-chip package 20 may be realized by a configuration including one collimating lens 16. This is because even this configuration is useful for reducing speckle.

(Example 3) In the description according to the third embodiment, the multi-chip package 30 is described as including a plurality of curved mirrors 37. However, the multi-chip package 30 may be realized by a configuration including one curved mirror 37.

As described above, in the multi-chip package according to the present disclosure, the number of constituent members can be flexibly changed.

The multi-chip package according to the present disclosure may be combined with configurations corresponding to each embodiment. For example, the multi-chip package according to the present disclosure may be realized by combining the configurations corresponding to the first embodiment, the second embodiment, and the third embodiment, respectively.

In FIG. 9, the collimating lenses 16 are irregularly arranged, and therefore the multi-chip package 21 can vary the angles, spatial spreads, and / or optical path lengths of the plurality of subbeams. Explained. Similarly, the plurality of curved mirrors 37 in FIG. 10 may be arranged irregularly with each other. This also applies to the curved lens 51 and the like in FIG.

The present disclosure is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

1,11,12,15,20,21,30,40,50,60,61,62,70,80,81,82,90,91,100,101,110,111,120,121,130 multi Chip Package 2 Package 2a Substrate 2b Side wall 3 Submount 4 Semiconductor laser chip 5, 5a, 5b Beam splitter (beam splitting part)
6, 6a, 6b, 6c, 6d Folded mirror (beam splitting part, reflector)
7, 7a, 7b angle mirror (reflecting part)
8 Cover 9 Polarized rotator 10 Lens 16, 41 Collimated lens (colimated part)
18 Beam splitter (beam splitting part)
19 Optical path length change part 37 Curved mirror (colimate part)
51 Curved lens (collimated part)
200 Projector 201 Beam forming optical system 202 Homogenizer 203 Spatial light modulator 204 Projection optical system 205 Screen

Claims (18)

It's a multi-chip package
With multiple semiconductor laser chips
A plurality of beam dividing portions composed of passive elements, which correspond to each of the plurality of semiconductor laser chips and divide the laser beam emitted from each of the plurality of semiconductor laser chips into a plurality of subbeams.
A multi-chip package including one or more reflecting portions that reflect the plurality of sub-beams to the outside of the multi-chip package. Each of the above multiple beam divisions
One or more beam splitters that split the laser beam into the plurality of subbeams,
The multi-chip package according to claim 1, further comprising one or more reflectors that reflect at least one of the plurality of subbeams split by the one or more beam splitters. The one or more reflectors include at least a first reflector, a second reflector, and a third reflector.
The one or more beam splitters include at least a first beam splitter.
Among the plurality of sub-beams, the one or more reflecting portions are external to the multi-chip package, the sub-beams circulating in the circulating optical path composed of at least the first reflector, the second reflector, and the first beam splitter. The multi-chip package according to claim 2, which reflects on the surface. The multi-chip package according to claim 2 or 3, wherein the one or more beam splitters are polarization-dependent beam splitters. At least one beam dividing part among the plurality of beam dividing parts
A beam division function unit that divides the laser beam into the plurality of sub-beams,
A substrate portion containing the beam dividing function portion inside or on the surface, and a substrate portion.
The multi-chip package according to claim 1. The multi-chip package according to any one of claims 1 to 5, further comprising one or more collimating portions that promote parallelization of the plurality of sub-beams emitted to the outside of the multi-chip package. The multi-chip package according to claim 6, wherein the one or more collimating portions are lenses provided between the plurality of semiconductor laser chips and the plurality of beam dividing portions. The multi-chip package according to claim 6, wherein the one or more collimating portions are curved mirrors provided between the plurality of semiconductor laser chips and the plurality of beam dividing portions. The multi-chip package according to claim 6, wherein the one or more collimating portions are provided on the wake side of the one or more reflecting portions. The above-mentioned one or more collimating portions include a plurality of collimating portions, and includes a plurality of collimating portions.
The multi-chip package according to any one of claims 6 to 9, wherein the plurality of collimating portions are irregularly arranged. The multi-chip package according to any one of claims 1 to 10, wherein the one or more reflecting units reflect at least one of the plurality of subbeams in a direction different from that of the other subbeams. The multi-chip package according to any one of claims 1 to 11, wherein the one or more reflecting units emit at least one of the plurality of subbeams in a direction different from that of the other subbeams. The multi-chip package according to any one of claims 1 to 12, wherein an optical path length changing portion having a non-uniform thickness is provided in the optical path of the plurality of subbeams. The multi-chip package according to any one of claims 1 to 13, wherein the one or more reflecting portions have at least two laser reflecting surfaces that intersect two laser beams incident from different directions. The multi-chip package according to any one of claims 1 to 14, wherein at least one of the plurality of semiconductor laser chips and the other semiconductor laser chips have different speed axis directions. The multi-chip package according to claim 3, further comprising a polarized rotator in the circulating optical path. The multi-chip package according to claim 5, wherein the beam dividing function portion is a dielectric or one or more metal reflective films, and the base portion is glass. A projector provided with the multi-chip package according to any one of claims 1 to 17.

Images