JP2019169644A - Semiconductor laser device - Google Patents

Abstract

To provide a semiconductor laser device capable of protecting a laser element part having a plurality of light-emitting portions from a surge voltage or the like.SOLUTION: A semiconductor laser device 1 includes a base (sub-mount 40), a laser element part (semiconductor laser array element 10) that is arranged above the base and has a plurality of light-emitting parts that emit laser light, and a Zener diode 20 disposed above the base and electrically connected to the laser element part.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a semiconductor laser device.

  Since semiconductor laser elements have advantages such as long life, high efficiency, and small size, they are used as light sources for various products including light sources for image display devices such as projectors and displays. In recent years, semiconductor laser elements are often used in projectors that project images on a large screen, such as theaters and projection mapping in large halls. In particular, projection mapping is used in the art field as a new entertainment tool.

  A semiconductor laser element used in a projector is desired to have a high output with a light output greatly exceeding 1 watt. For example, a high output of several tens of watts or more is desired. However, it is difficult to obtain a high output with one laser beam. For this reason, in order to increase the output, a semiconductor laser array device in which a plurality of semiconductor laser elements are arranged or a semiconductor laser array element having a plurality of emitters (light emitting portions) is used.

  When a surge voltage (a large transient voltage due to static electricity, etc.) is applied to the semiconductor laser element, a large current flows instantaneously in the semiconductor laser element, causing strong laser oscillation, causing a so-called end face breakdown and causing the semiconductor laser element to fail. End up. For this reason, in order to protect the semiconductor laser element, a technique is known in which a Zener diode having a pn junction opposite to the pn junction of the semiconductor laser element is connected in parallel with the semiconductor laser element (Patent Document 1). When the Zener diode reaches a predetermined reverse voltage (for example, 5 V), a large current flows through the avalanche breakdown phenomenon, so that the resistance value is substantially zero. That is, a resistance having a resistance value of almost zero is connected in parallel with the semiconductor laser element. Thus, by connecting a Zener diode in parallel to the semiconductor laser element, it is possible to prevent a surge voltage from being applied to the semiconductor laser element.

JP-A-8-52582

  Generally, a semiconductor laser element (semiconductor laser chip) is incorporated in a package and sold as a semiconductor laser device. That is, a component manufacturer that manufactures and sells a semiconductor laser device incorporates a semiconductor laser element into a package and sells it as a semiconductor laser device. A set manufacturer purchases a semiconductor laser device in which a semiconductor laser element is incorporated from a component manufacturer, and mounts the semiconductor laser device on a set product (for example, a projector) in an assembly process. For this reason, even if the set manufacturer protects the semiconductor laser element with a Zener diode as disclosed in Patent Document 1, the Zener diode is disposed outside the semiconductor laser device.

  In this case, the semiconductor laser element in the semiconductor laser device is not protected from the surge voltage before the Zener diode is arranged. For this reason, when a set maker handles a semiconductor laser device in the assembly process, static electricity existing in the assembly process is transmitted to the semiconductor laser element through a support member in the semiconductor laser device, and the semiconductor laser element is subjected to electrostatic breakdown. May cause. At this time, the laser light emitting end face of the semiconductor laser element is damaged even if the semiconductor laser element is not completely destroyed (that is, in a state where no laser light is output). As a result, there is a problem that the life of the semiconductor laser element, and by extension, the semiconductor laser device is reduced, and the reliability guaranteed by the component manufacturer that manufactures the semiconductor laser device cannot be obtained.

  In particular, when a semiconductor laser device incorporating a multi-emitter structure semiconductor laser array element having a plurality of emitters (light emitting portions) as a semiconductor laser element is mounted on a set product, a surge voltage (transient voltage) or Surge current (transient current) is likely to enter.

  A multi-emitter semiconductor laser array element having a plurality of emitters has a structure in which emitters are connected in parallel as an electric circuit. For example, in a semiconductor laser array element having n emitters, it is necessary to pass a large current of n × I in order to operate each emitter with a current I.

  In this case, if the contact resistance between the package electrode portion of the semiconductor laser device and the power supply line is large, the loss due to a large current increases. Therefore, a semiconductor laser device using a multi-emitter structure semiconductor laser array element is mounted on a set product. At this time, the package electrode portion and the power supply line are connected and fixed with screws. That is, by connecting the package electrode part and the power supply line by screws, the package electrode part and the power supply line are brought into close contact with each other to reduce the contact resistance.

  Further, the connection of the package electrode unit and the power supply line by screws is also for ensuring safety. This is because, in the unlikely event that the package electrode section and the power supply line are disconnected, a large current for operating the semiconductor laser array element may be short-circuited to induce ignition. In order to avoid such a problem, the package electrode part and the power supply line are connected by screws.

  As described above, when a semiconductor laser device using a semiconductor laser array element having a multi-emitter structure is mounted on a set component, the package electrode portion and the power supply line are often connected by screws.

  In this case, since the process of screwing the package electrode portion and the power supply line involves a rotation operation, static electricity is likely to occur. For this reason, when the semiconductor laser device is mounted on a set product, there is a high possibility that a surge voltage or surge current will be caused by static electricity.

  Since a single-emitter semiconductor laser element having a single light-emitting portion has a small drive current, when a semiconductor laser device incorporating a single-emitter semiconductor laser element is mounted on a set product, Simply inserts the lead pin of the semiconductor laser device into the connector.

  Thus, a semiconductor laser device incorporating a semiconductor laser array element having a multi-emitter structure is more sensitive to static electricity or the like when handled in an assembly process or the like than a semiconductor laser device incorporating a semiconductor laser element having a single emitter structure. There is a high possibility that a surge voltage or surge current will enter, and there is a problem that the semiconductor laser device is likely to fail.

  The present disclosure has been made to solve such a problem, and an object thereof is to provide a semiconductor laser device capable of protecting a laser element portion having a plurality of light emitting portions from a surge voltage or the like.

  In order to achieve the above object, an aspect of a semiconductor laser device according to the present disclosure includes a base, a laser element unit that is disposed above the base and has a plurality of light emitting units that emit laser light, and A Zener diode disposed above the base and electrically connected to the laser element portion.

  Since the laser element portion having a plurality of light emitting portions can be protected from a surge voltage or the like, a highly reliable semiconductor laser device excellent in surge resistance can be realized.

1 is an external perspective view of a semiconductor laser device according to a first embodiment. 1 is a perspective view showing an internal structure of a semiconductor laser device according to a first embodiment. 1 is a perspective view showing a configuration of a main part of a semiconductor laser device according to a first embodiment. 1 is a perspective view of a semiconductor laser array element incorporated in a semiconductor laser device according to a first embodiment. FIG. 4 is a diagram showing an electric circuit on a submount of the semiconductor laser device according to the first embodiment. FIG. 5 is a perspective view showing an internal structure of a semiconductor laser device according to a second embodiment. FIG. 5 is a diagram showing an electric circuit on a submount of a semiconductor laser device according to a second embodiment. FIG. 10 is a perspective view showing a configuration of a main part of a semiconductor laser device according to Modification 1 of Embodiment 2. FIG. 10 is a perspective view of relevant parts of a semiconductor laser device according to a second modification of the second embodiment. FIG. 10 is a perspective view showing a configuration of a main part of a semiconductor laser device according to Modification 3 of Embodiment 2. FIG. 10 is a perspective view showing a configuration of a main part of a semiconductor laser device according to Modification 4 of Embodiment 2. FIG. 10 is a perspective view showing a configuration of a main part of a semiconductor laser device according to Modification 5 of Embodiment 2. FIG. 11 is a plan view showing a configuration of a main part of a semiconductor laser device according to Modification 5 of Embodiment 2. It is a figure which shows the relationship of the geometric distance of the semiconductor laser array element and Zener diode in the semiconductor laser apparatus which concerns on the modification 5 of Embodiment 2. FIG. FIG. 10 is a perspective view showing a configuration of a main part of a semiconductor laser device according to Modification 6 of Embodiment 2. FIG. 10 is a perspective view showing a configuration of a main part of a semiconductor laser device according to Modification 7 of Embodiment 2. FIG. 24 is a perspective view showing a modified example of the Zener diode used in the semiconductor laser device according to Modified Example 7 of Embodiment 2. FIG. 12 is a perspective view showing another modification example of the Zener diode used in the semiconductor laser device according to Modification Example 7 of Embodiment 2. 6 is a schematic diagram of a projector according to Embodiment 3. FIG. It is a perspective view which shows the internal structure of the semiconductor laser apparatus which concerns on a modification. 6 is a perspective view of a semiconductor laser array element according to Modification 1. FIG. 10 is a perspective view of a semiconductor laser array element according to Modification 2. FIG.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, component arrangement positions and connection forms, steps (steps) and order of steps, and the like shown in the following embodiments are merely examples and limit the present disclosure. It is not the purpose to do. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present disclosure are described as arbitrary constituent elements.

  Each figure is a mimetic diagram and is not necessarily illustrated strictly. Accordingly, the scales and the like do not necessarily match in each drawing. In each figure, substantially the same components are denoted by the same reference numerals, and redundant descriptions are omitted or simplified.

(Embodiment 1)
[Semiconductor laser device]
First, the configuration of the semiconductor laser device 1 according to the first embodiment will be described with reference to FIGS. FIG. 1 is an external perspective view of a semiconductor laser device 1 according to the first embodiment. FIG. 2 is a perspective view showing the internal structure of the semiconductor laser device 1, and shows a state in which the cap 70 is removed in FIG. FIG. 3 is a perspective view showing the configuration of the main part of the semiconductor laser device 1.

  The semiconductor laser device 1 is a light emitting device in which a semiconductor laser array element 10 that emits laser light is packaged. As shown in FIGS. 1 and 2, the semiconductor laser device 1 according to the present embodiment is a light emitting device of a CAN package type in which a semiconductor laser array element 10 is covered with a cap (can) 70 constituting a package.

  As shown in FIGS. 2 and 3, the semiconductor laser device 1 includes a semiconductor laser array element 10 and a Zener diode 20, a surface electrode 30 to which the semiconductor laser array element 10 and the Zener diode 20 are connected, and a surface electrode 30. The submount 40 is provided. The submount 40 is a base on which the semiconductor laser array element 10 and the Zener diode 20 are arranged. In the present embodiment, the surface electrode 30 is formed on the submount 40.

  The semiconductor laser device 1 further includes a heat sink block 50 for mounting the submount 40, a package base 60 to which the heat sink block 50 is fixed, and a cap 70 that covers the semiconductor laser array element 10 and the Zener diode 20. . The semiconductor laser array element 10 and the Zener diode 20 are accommodated in a cap 70 constituting a package.

  The semiconductor laser array element 10 is disposed above the submount 40. In the present embodiment, the semiconductor laser array element 10 is mounted on the submount 40 on which the surface electrode 30 is formed. Specifically, the semiconductor laser array element 10 is mounted on the surface electrode 30 and is electrically and mechanically connected to the surface electrode 30. As an example, the semiconductor laser array element 10 is soldered to the surface electrode 30 by AuSn solder. A specific configuration of the semiconductor laser array element 10 will be described later.

  The Zener diode 20 is disposed above the submount 40. In the present embodiment, the Zener diode 20 is mounted on the submount 40 on which the surface electrode 30 is formed, like the semiconductor laser array element 10. Specifically, the Zener diode 20 is mounted on the surface electrode 30 and is electrically and mechanically connected to the surface electrode 30. As an example, the Zener diode 20 is also soldered to the surface electrode 30.

  When the emitting direction of the laser light emitted from the semiconductor laser array element 10 is the front and the direction orthogonal to the front is the side, the Zener diode 20 is disposed on the side of the semiconductor laser array element 10. That is, the semiconductor laser array element 10 and the Zener diode 20 are arranged side by side.

  The Zener diode 20 is a constant voltage diode having a pn junction. As an example, the Zener diode 20 has a structure in which an n layer and an n + layer are stacked on a p-type silicon substrate. In the present embodiment, the breakdown voltage of the Zener diode 20 is about 5V.

  Zener diode 20 is electrically connected to semiconductor laser array element 10. Specifically, the semiconductor laser array element 10 and the Zener diode 20 are connected in parallel via the surface electrode 30. The semiconductor laser array element 10 and the Zener diode 20 are electrically mounted so that the pn junction of the semiconductor laser array element 10 and the pn junction of the Zener diode 20 are in the opposite directions. As will be described later, in the present embodiment, the semiconductor laser array element 10 is an n-type substrate, and is connected to the surface electrode 30 by face-up mounting. Therefore, the Zener diode 20 using the p-type substrate has a surface on the substrate side so that the semiconductor laser array element 10 and the Zener diode 20 are electrically connected with the pn junction in the reverse direction through the surface electrode 30. It is joined to the electrode 30.

  The surface electrode 30 is formed on the upper surface of the submount 40. The surface electrode 30 is a metal thin film made of a metal material such as copper or silver. The submount 40 is made of a metal material such as aluminum or copper, or a high thermal conductivity material such as diamond or SiC. The submount 40 may be made of a conductive material or may be made of an insulating material. In the present embodiment, the submount 40 is made of SiC.

  The submount 40 on which the semiconductor laser array element 10 and the Zener diode 20 are mounted via the surface electrode 30 is fixed to the heat sink block 50. The heat sink block 50 is a post portion protruding from the package base 60. The heat sink block 50 is made of a metal material such as copper, for example. In this case, the submount 40 is soldered to the surface of the heat sink block 50 by AuSn solder.

  The package base 60 is a disk-shaped metal support member made of a metal material such as aluminum. In the present embodiment, the package base 60 and the heat sink block 50 are separated from each other. However, the package base 60 and the heat sink block 50 may be configured as a single body.

  A pair of lead pins 61 a and 61 b fixed by an insulating low melting point glass 62 is attached to the package base 60. The pair of lead pins 61a and 61b receives power to be supplied to the semiconductor laser array element 10 from the outside. The pair of lead pins 61 a and 61 b penetrate the package base 60, and a part of the lead pins 61 a and 61 b is exposed to the outside as a package electrode part of the semiconductor laser device 1. When the semiconductor laser device 1 is mounted on another component or product, the lead pins 61a and 61b exposed to the outside are connected to a supply power line. In this case, the lead pins 61a and 61b and the power supply line are connected by, for example, screwing.

  One electrode (the electrode on which crystal growth has been performed) of the semiconductor laser array element 10 is electrically connected to the lead pin 61a by wires 81 (five in FIG. 2). On the other hand, the other electrode (electrode on the back side of the substrate) of the semiconductor laser array element 10 is electrically connected to the lead pin 61b via the surface electrode 30 and the wire 82. The wire 82 is connected to the surface electrode 30 and the lead pin 61b.

  One electrode (the electrode on which crystal growth has been performed) of the Zener diode 20 is electrically connected to the lead pin 61a by a wire 82. On the other hand, the other electrode (electrode on the back side of the substrate) of the Zener diode 20 is electrically connected to the lead pin 61 b through the surface electrode 30 and the wire 83. That is, the wire 83 is electrically connected to both the semiconductor laser array element 10 and the Zener diode 20 via the surface electrode 30.

  The wires 81, 82, and 83 are Au wires, for example, and are stretched by wire bonding mounting.

  A cap 70 is fixed to the package base 60. The cap 70 is disposed so as to cover the heat sink block 50 in which the semiconductor laser array element 10 and the Zener diode 20 mounted on the submount 40 are disposed. The cap 70 is a metal cylindrical body constituting the package. A window glass 71 is attached to the cap 70. The window glass 71 is an example of a translucent member that transmits laser light emitted from the semiconductor laser array element 10, and is a plate glass in the present embodiment. The cap 70 is filled with an inert gas for protecting the laser end face of the semiconductor laser array element 10.

[Semiconductor laser array element]
Here, the configuration of the semiconductor laser array element 10 according to the present embodiment will be described with reference to FIG. FIG. 4 is a perspective view of the semiconductor laser array element 10 incorporated in the semiconductor laser device 1 according to the first embodiment.

  The semiconductor laser array element 10 is an example of a laser element unit having a plurality of emitters 130 (light emitting units) that emit laser light, and includes a substrate 120 and a laser array unit 110 positioned on the substrate 120. The semiconductor laser array element 10 has a plurality of emitters 130 on the same substrate 120.

  In the laser array section 110, a plurality of emitters 130 that emit laser light are arranged side by side. That is, the semiconductor laser array element 10 is a semiconductor laser element having a multi-emitter structure including a plurality of emitters 130. Each emitter 130 is a light emitting region that emits light when current is injected into the laser array unit 110.

  The laser array unit 110 includes a first clad layer 111, a first guide layer 112, an active layer 113, a second guide layer 114, a second clad layer 115, and a contact layer 116 laminated in this order. Is the body. Note that the layer structure of the laser array unit 110 is not limited to the above-described stacked body, and an electron overflow suppression layer or the like may be formed in addition to the above layers.

  The laser array unit 110 has a pair of first end face 10 a and second end face 10 b that face each other in the resonator length direction of the semiconductor laser array element 10. In the present embodiment, the first end face 10a is a front end face from which laser light is emitted (laser light emission end face), and the second end face 10b is a rear end face. Note that a reflective film made of a dielectric multilayer film may be formed on the first end face 10a and the second end face 10b as an end face coat film. In this case, it is preferable that a low reflection film is formed on the first end surface 10a from which the laser light is emitted, and a high reflection film is formed on the second end surface 10b.

  The laser array section 110 has a ridge waveguide structure having a ridge section 140. Specifically, the laser array unit 110 has a plurality of ridge portions 140. In the present embodiment, five ridge portions 140 are formed in the laser array portion 110. The second cladding layer 115 and the contact layer 116 are separated into a plurality by five ridge portions 140. Each ridge 140 extends linearly in the laser resonator length direction (laser beam oscillation direction).

  In the present embodiment, the ridge portion 140 is formed from the boundary between the second guide layer 114 and the second cladding layer 115, but the ridge is formed from the middle of the second guide layer 114 or the second cladding layer 115. The part 140 may be formed.

  Each of the plurality of ridge portions 140 corresponds to each of the plurality of emitters 130. That is, the emitter 130 and the ridge portion 140 correspond one to one. In the present embodiment, since the laser array unit 110 is provided with the five ridges 140, the laser array unit 110 includes five emitters 130.

  The five emitters 130 are arranged in a straight line along a direction orthogonal to the laser resonator length direction (that is, the width direction of the ridge portion 140). That is, in the laser array unit 110, five emitters 130 are arranged in the horizontal direction.

  Further, the semiconductor laser array element 10 is provided with a first electrode 151 and a second electrode 152 in order to inject current into the laser array unit 110. The first electrode 151 is an ohmic electrode formed so as to be in contact with the contact layer 116 of each ridge portion 140. The second electrode 152 is an ohmic electrode provided on the back surface of the substrate 120.

  In addition, an insulating layer 160 is formed so as to cover the side surface of the ridge portion 140 and the flat portion extending laterally from the root of the ridge portion 140. By forming the insulating layer 160, the injected current can be prevented from flowing into a region between the two adjacent ridge portions 140.

  The semiconductor laser array element 10 configured as described above is mounted on the submount 40 on which the surface electrode 30 is formed. Specifically, the second electrode 152 of the semiconductor laser array element 10 is soldered to the surface electrode 30 by AuSn solder. Thereafter, the first electrode 151 and the lead pin 61 a are wire bonded by the wire 81. Further, the surface electrode 30 joined to the second electrode 152 and the lead pin 61 b are wire-bonded by the wire 83.

  When a voltage is applied to the first electrode 151 and the second electrode 152 by the pair of lead pins 61 a and 61 b, a current flows between the first electrode 151 and the second electrode 152. That is, current is injected into the laser array unit 110. The current injected into the laser array part 110 flows only below the ridge part 140. As a result, a current is injected into the active layer 113 immediately below the ridge portion 140, and electrons and holes are recombined in the active layer 113 to emit light.

  The light generated in the active layer 113 is, in the substrate vertical direction (longitudinal direction), the first cladding layer 111, the first guide layer 112, the active layer 113, the second guide layer 114, the second cladding layer 115, and the contact. It is confined by the refractive index difference between each layer of the layer 116. On the other hand, the light generated in the active layer 113 has a refractive index between the inside of the ridge 140 (second clad layer 115 and contact layer 116) and the outside of the ridge 140 (insulating layer 160) in the horizontal direction (lateral direction) of the substrate. Trapped by the difference. As described above, the semiconductor laser array element 10 in the present embodiment is a refractive index waveguide type semiconductor laser.

  The light generated in the active layer 113 resonates by reciprocating between the first end face 10a and the second end face 10b, and gain is obtained by the injection current, so that the high-intensity laser light having the same phase is obtained. 10L is emitted from the emitter 130 of the first end face 10a. In the present embodiment, since the five ridge portions 140 are formed, the laser light 10L is emitted from each of the five emitters 130. That is, five laser beams 10L are emitted from the laser array unit 110. The point where the laser beam 10L is emitted from the first end face 10a is the emission point of the emitter 130.

  The oscillation wavelength (emission color) of the laser beam can be adjusted by changing the material of each layer of the laser array unit 110. For example, red, green, and blue laser beams can be oscillated.

The semiconductor laser array element 10 in the present embodiment is configured to emit red laser light. In this case, a semiconductor substrate made of a GaAs substrate is used as the substrate 120, and the laser array unit 110 is made of Al _x Ga _y In _1-xy As _z P _1-z (where 0 ≦ x, y, z ≦ 1, The semiconductor laser array element 10 that emits red laser light can be obtained by using a semiconductor material made of a group III-V compound semiconductor represented by 0 ≦ x + y ≦ 1.

  Specifically, an n-type GaAs substrate having a thickness of 80 μm and a main surface of (100) plane can be used as the substrate 120. In this case, as the laser array unit 110 made of an AlGaInP-based semiconductor material, an n-type cladding layer is used as the first cladding layer 111, an undoped n-side guide layer is used as the first guide layer 112, and an undoped layer is used as the active layer 113. An active layer can be used, an undoped p-side guide layer can be used as the second guide layer 114, a p-type cladding layer can be used as the second cladding layer 115, and a p-type contact layer can be used as the contact layer 116.

As an example, the first cladding layer 111 is n- (Al _0.6 Ga _0.4 ) _0.5 In _0.5 P with a thickness of 1 μm, and the first guide layer 112 has a thickness of 0.1 μm. u- (Al _0.4 Ga _0.6 ) _0.5 In _0.5 P, the active layer 113 is u-In _0.5 Ga _0.5 P with a thickness of 10 nm, and the second guide layer 114 had a thickness of 0.1μm of _{u- (Al 0.4 Ga 0.6) 0.5} in 0.5 P, the second cladding layer 115 has a thickness of 0.5μm of p- (Al _0.6 Ga _0.4 ) _0.5 In _0.5 P, and the contact layer 116 is p-GaAs having a thickness of 0.1 μm. The first electrode 151 is a p-side electrode, and the second electrode 152 is an n-side electrode, and each is made of a metal material such as Cr, Ti, Ni, Pd, Pt, or Au.

  The element width of the semiconductor laser array element 10 is 1200 μm, and the resonator length of the semiconductor laser array element 10 is 1 mm. In this case, the ridge width of one ridge portion 140 is 5 μm, and the interval between two adjacent emitters 130 (emitter interval) is 200 μm.

[Effects]
As described above, in a semiconductor laser device in which a semiconductor laser array element having a plurality of emitters (light emitting portions) is incorporated, a large current needs to flow through the semiconductor laser array element. When the integrated semiconductor laser device is mounted on a set product, the package electrode portion and the power supply line are connected by screws. For this reason, static electricity is likely to be generated in the process of screwing the package electrode portion and the power supply line, and a surge voltage or surge current is likely to enter the semiconductor laser device.

  Therefore, in the semiconductor laser device 1 according to the present embodiment, the electrically connected semiconductor laser array element 10 and the Zener diode 20 are disposed above the same submount 40. That is, the semiconductor laser array element 10 and the Zener diode 20 are incorporated in the semiconductor laser device 1 in which the semiconductor laser array element 10 is packaged. Specifically, the semiconductor laser array element 10 and the Zener diode 20 are connected in parallel via a surface electrode 30 formed on the upper surface of the submount 40.

  With this configuration, a surge protection circuit that protects the semiconductor laser array element 10 from surge voltage or surge current by the Zener diode 20 can be provided in the package of the semiconductor laser device 1.

  As a result, even if a surge voltage or the like is generated when the semiconductor laser device 1 including the semiconductor laser array element 10 having a plurality of light emitting portions is handled, the surge voltage is generated inside the semiconductor laser device 1. It is possible to prevent the semiconductor laser array element 10 from being damaged due to the above. That is, the Zener diode 20 can protect the semiconductor laser array element 10 from a surge voltage or the like, and can prevent the semiconductor laser array element 10 from failing. That is, surge resistance can be improved.

  For example, when a surge voltage enters the semiconductor laser device 1 in an assembly process of a set manufacturer that mounts the semiconductor laser device 1 as a component on a set product, the surge voltage is transmitted via the lead pins 61a and 61b or the package base 60. The semiconductor laser array element 10 is directed to, but since the Zener diode 20 is electrically connected in parallel to the semiconductor laser array element 10, the surge voltage propagates through the Zener diode 20. Thereby, since it is possible to prevent the surge voltage from being applied to the semiconductor laser array element 10, it is possible to suppress the failure of the semiconductor laser array element 10 due to the surge voltage.

  Moreover, since the semiconductor laser device 1 is delivered in the state shown in FIG. 1 from the manufacturer (component manufacturer) that manufactures the semiconductor laser device 1, the user who purchased the semiconductor laser device 1 (set the semiconductor laser device 1) A set manufacturer or the like mounted on the product does not directly contact the semiconductor laser array element 10. Therefore, the semiconductor laser array element 10 and the Zener diode 20 can be protected from mechanical contact.

  As described above, according to the semiconductor laser device 1 according to the present embodiment, the semiconductor laser array element 10 can be mechanically and electrically protected, so that the highly reliable semiconductor laser device 1 can be realized. it can.

  In the present embodiment, the Zener diode 20 is disposed on the side of the semiconductor laser array element 10.

  With this configuration, the Zener diode 20 can be mounted on the same submount 40 as the semiconductor laser array element 10 without affecting the laser light emitted from the semiconductor laser array element 10. For example, it can be avoided that the laser light emitted from the semiconductor laser array element 10 is blocked by the Zener diode 20.

(Embodiment 2)
Next, the semiconductor laser device 2 according to the second embodiment will be described.

  When the Zener diode 20 is built in the packaged semiconductor laser device 1 as in the semiconductor laser device 1 according to the first embodiment, the Zener diode 20 and the semiconductor laser array element 10 are electrically connected to each other such as an electric wiring. It is connected via a member. Specifically, as shown in FIG. 2, in the first embodiment, the Zener diode 20 and the semiconductor laser array element 10 are electrically connected via the surface electrode 30.

  In this case, a resistance component such as the surface electrode 30 exists between each emitter 130 (ridge portion 140) of the semiconductor laser array element 10 and the Zener diode 20. Specifically, between the n side (substrate 120 side) of each emitter 130 of the semiconductor laser array element 10 and the Zener diode 20, each layer in the semiconductor laser array element 10 including the resistance component of the surface electrode 30. Resistance components (electrical resistance) such as the resistance component of the substrate 120, the resistance component of the substrate 120, and the resistance component of the submount 40 (when the submount 40 has conductivity). In particular, since the surface electrode 30 is a thin film, it cannot be largely ignored as a resistance component.

  Considering the resistance component between each emitter 130 of the semiconductor laser array element 10 and the Zener diode 20, the semiconductor laser array element 10 and the Zener diode 20 are electric circuits having resistance components R1 to R5 as shown in FIG. Will be configured. FIG. 5 is a diagram showing an electric circuit on the submount 40 of the semiconductor laser device 1 according to the first embodiment.

  As shown in FIG. 5, when the five emitters 130 of the semiconductor laser array element 10 are represented as E1 to E5, resistance components R1 to R5 are generated between the five emitters E1 to E5 and the Zener diode 20, respectively. Yes.

  At this time, the resistance between the Zener diode 20 and each emitter 130 of the semiconductor laser array element 10 varies depending on the distance between the Zener diode 20 and each emitter 130 of the semiconductor laser array element 10. Specifically, the resistance with the Zener diode 20 increases as the emitter 130 is located farther from the Zener diode 20. In particular, when the submount 40 is insulative, the value of the resistance component between the Zener diode 20 and each emitter 130 increases.

  For this reason, when a surge voltage enters the semiconductor laser device 1, a time delay occurs in how the surge voltage is transmitted to each emitter 130 due to a time constant difference associated with the resistance components R1 to R5. The protection effect of each emitter 130 by the Zener diode 20 differs according to the magnitude of the resistance between the emitter 130 and the resistor 130.

  Specifically, the emitter 130 having a small resistance to the Zener diode 20 (for example, the emitter E1 close to the Zener diode 20) is easily protected by the Zener diode 20 because the time constant associated with the resistance component is small. The emitter 130 having a large electric resistance with the diode 20 (for example, the emitter E5 far from the Zener diode 20) has a relatively large protection time due to the resistance component, and therefore the protection effect by the Zener diode 20 is relatively small.

  Therefore, in the semiconductor laser device 1 according to the first embodiment, there is a problem with respect to surge resistance as the entire device. This problem is particularly caused when the number of emitters of the semiconductor laser array element is large (for example, 20 or more), or This is particularly noticeable when the element width of the semiconductor laser array element is large (for example, around 1 mm) or when face-down mounting described later.

  Therefore, in order to eliminate the influence of the protective effect of the Zener diode 20 due to this resistance component difference, the semiconductor laser device 2 according to the present embodiment, as shown in FIG. It is arranged on both sides of the side. In other words, in the present embodiment, the Zener diodes 20 are arranged on one side and the other side of the semiconductor laser array element 10. In this case, the two Zener diodes 20 are preferably arranged at substantially symmetrical positions around the semiconductor laser array element 10. Each of the two Zener diodes 20 is connected to the lead pin 61a by the wire 82 as in the first embodiment. In addition, the two Zener diodes 20 are both bonded to the surface electrode 30 on the substrate side as in the first embodiment.

  In this case, considering the resistance component between each emitter 130 of the semiconductor laser array element 10 and the Zener diode 20, the semiconductor laser array element 10 and the Zener diode 20 have resistance components R1 to R6 as shown in FIG. The electric circuit which has is comprised. FIG. 7 is a diagram showing an electric circuit on the submount 40 of the semiconductor laser device 2 according to the second embodiment.

  As shown in FIG. 7, in the semiconductor laser device 2 according to the present embodiment, since the Zener diodes 20 are arranged on both sides of the semiconductor laser array element 10, each of the five emitters E1 to E5 has two Zeners. Resistance components R <b> 1 to R <b> 6 are generated between the diode 20. A resistance component R7 is also generated between the two Zener diodes 20.

  At this time, the emitters E1 and E5 close to the Zener diode 20 are protected by the Zener diode 20. On the other hand, the resistance component between the center emitter E3 and the Zener diode 20 is larger than that of the emitters E1 and E5, but the resistance component between the Zener diode 20 and the Zener diode 20 is about half that of the first embodiment. Therefore, the protection effect by the Zener diode 20 can be improved as compared with the first embodiment.

  As described above, according to the semiconductor laser device 2 according to the present embodiment, the Zener diodes 20 are arranged on both sides of the semiconductor laser array element 10.

  With this configuration, for each emitter 130 of the semiconductor laser array element 10, the difference in resistance component between the Zener diode 20 and each emitter can be reduced, so that the resistance component between each emitter 130 and the Zener diode 20 can be reduced. Can be made uniform. Thereby, since it is possible to suppress the surge voltage from being concentrated on the specific emitter 130, the surge resistance of the entire semiconductor laser device 2 can be improved.

  In the present embodiment, the substrate side (n side) of the semiconductor laser array element 10 is bonded to the surface electrode 30, but the crystal growth side (p side) electrode of the semiconductor laser array element 10 is enhanced in order to improve heat dissipation. May be bonded to the surface electrode 30. That is, the semiconductor laser array element 10 may be face-down mounted (junction down mounted) on the submount 40 on which the surface electrode 30 is formed. In this case, the Zener diode 20 is also subjected to junction down mounting so that the pn junction of the semiconductor laser array element 10 and the pn junction of the Zener diode 20 are opposite to each other, or the Zener diode 20 is mounted on the n-type substrate. A p-layer and a p + layer may be used.

(Modification 1 of Embodiment 2)
Next, a semiconductor laser device 2A according to Modification 1 of Embodiment 2 will be described with reference to FIG. FIG. 8 is a perspective view showing the configuration of the main part of the semiconductor laser device 2A according to the first modification of the second embodiment.

  In the semiconductor laser device 2 shown in FIG. 6, the semiconductor laser array element 10 or the Zener diode 20 and the lead pins 61a and 61b are electrically connected using the wires 81 to 83. There is a resistance component. For this reason, there are some electrical resistance components on the p-side of each emitter 130 and the n-side of the Zener diode 20 of the semiconductor laser array element 10, thereby obstructing the uniformity of the resistance component between the emitter 130 and the Zener diode 20. To do.

  Therefore, in the semiconductor laser device 2A according to the present modification, as shown in FIG. 8, the semiconductor laser array element 10 and the two Zener diodes 20 are connected in parallel without using the wires 81-83.

  Specifically, a conductive metal block (lower metal block) is used as the heat sink block 50, and a metal block 50A (upper metal block) is further used. The metal block 50A is arranged at a position opposite to the heat sink block 50 (submount 40) with the semiconductor laser array element 10 and the Zener diode 20 in between.

  Then, the semiconductor laser array element 10 and the Zener diode 20 are joined in a state of being sandwiched between the heat sink block 50 and the metal block 50A. Each of the heat sink block 50 and the metal block 50A, and the semiconductor laser array element 10 and the Zener diode 20 are electrically and mechanically joined by a conductive adhesive such as solder.

  In FIG. 8, the conductive adhesive is not shown, and the semiconductor laser array element 10 and the Zener diode 20 and the metal block 50A are shown as being separated from each other. The laser array element 10 and the Zener diode 20 and the metal block 50A are connected by a conductive adhesive.

  As the heat sink block 50 and the metal block 50A, for example, a copper block made of copper can be used. In this modification, the submount 40 may also have conductivity. This facilitates electrical conduction through the heat sink block 50, and an electrical conduction path from the heat sink block 50 to the semiconductor laser array element 10 and the Zener diode 20 can be easily secured.

  Thus, according to the semiconductor laser device 2A according to the present modification, the semiconductor laser array element 10 and the two Zener diodes 20 are sandwiched between the two metal blocks without using the thin wires 81 to 83 having a high resistance component. It is connected in parallel.

  With this configuration, the resistance components on the p side of each emitter 130 and the n side of the Zener diode 20 of the semiconductor laser array element 10 can be made uniform as compared with the semiconductor laser device 2 shown in FIG. The surge resistance can be improved.

  The semiconductor laser device 2A according to this modification and the semiconductor laser device 2 shown in FIG. 6 have the same configuration except that the metal block 50A is used instead of the wires 81-83.

(Modification 2 of Embodiment 2)
Next, a semiconductor laser device 2B according to Modification 2 of Embodiment 2 will be described with reference to FIG. FIG. 9 is a perspective view showing a configuration of a main part of a semiconductor laser device 2B according to the second modification of the second embodiment.

  As shown in FIG. 9, in the semiconductor laser device 2B according to this modification, when the emitting direction of the laser light emitted from the semiconductor laser array element 10 is the front and the direction opposite to the front is the rear, the Zener diode 20 Are arranged behind the semiconductor laser array element 10. That is, in this modification, only one Zener diode 20 is used, but the Zener diode 20 is disposed at a position facing the second end face 10 b (rear end face) of the semiconductor laser array element 10. Specifically, the Zener diode 20 is disposed behind the semiconductor laser array element 10 at a position that passes through the central axis J of the semiconductor laser array element 10.

  In this case, if the distance between the Zener diode 20 and the semiconductor laser array element 10 is L and the distance between the emitters 130 (ridge portions 140) at both ends is W, atan (W / 2L) <acos (0.9) ≈25 deg. By setting L so as to satisfy, the difference between the resistance component between the emitter 130 located at the extreme end and the Zener diode 20 and the resistance component between the emitter 130 located at the center and the Zener diode 20 can be obtained. 10% or less.

  As a result, the resistance component between each emitter 130 and the Zener diode 20 can be made uniform for each emitter 130 of the semiconductor laser array element 10, so that the surge resistance of the entire semiconductor laser device 2B can be improved.

  The semiconductor laser device 2B according to the present modification and the semiconductor laser device 2 shown in FIG. 6 have the same configuration except for the number and position of the Zener diodes 20.

(Modification 3 of Embodiment 2)
Next, a semiconductor laser device 2C according to Modification 3 of Embodiment 2 will be described with reference to FIG. FIG. 10 is a perspective view showing a configuration of a main part of a semiconductor laser device 2C according to Modification 3 of Embodiment 2.

  As shown in FIG. 10, in the semiconductor laser device 2 </ b> C according to this modification, three or more zener diodes 20 are arranged around the semiconductor laser array element 10. Thereby, for each emitter 130 of the semiconductor laser array element 10, the resistance component between each emitter 130 and the Zener diode 20 can be easily uniformized.

  Specifically, in the present modification, one is disposed on each side and rear of the semiconductor laser array element 10, and a total of three Zener diodes 20 are disposed around the semiconductor laser array element 10. ing.

  As described above, according to this modification, the resistance component between each emitter 130 and the Zener diode 20 can be made uniform for each emitter 130 of the semiconductor laser array element 10, so that the surge resistance of the entire semiconductor laser device 2C can be improved. Can be improved.

  The semiconductor laser device 2C according to the present modification and the semiconductor laser device 2 shown in FIG. 6 have the same configuration except for the number and position of the Zener diodes 20.

(Modification 4 of Embodiment 2)
Next, a semiconductor laser device 2D according to Modification 4 of Embodiment 2 will be described with reference to FIG. FIG. 11 is a perspective view showing a configuration of a main part of a semiconductor laser device 2D according to the fourth modification of the second embodiment.

  As shown in FIG. 11, in the semiconductor laser device 2D according to this modification, the surface electrode 30D formed on the submount 40 is divided into a plurality of parts. Specifically, the surface electrode 30 </ b> D is electrically separated into a plurality corresponding to each of the plurality of emitters 130 of the semiconductor laser array element 10. That is, the semiconductor laser device 2D has the same number of surface electrodes 30D as the number of emitters 130 (ridge portions 140). Further, the surface electrodes 30D have the same shape. Accordingly, each of the plurality of surface electrodes 30D has the same resistance component.

  In this modification, the semiconductor laser array element 10 is face-down mounted (junction down mounted). That is, the semiconductor laser array element 10 is bonded to the surface electrode 30 such that the first electrode 151 (p-side electrode) is on the surface electrode 30 side. Specifically, each of the plurality of first electrodes 151 is bonded to each of the plurality of surface electrodes 30D on a one-to-one basis.

  A plurality of Zener diodes 20 are arranged according to the plurality of separated surface electrodes 30D. That is, the Zener diode 20 is disposed on each of the plurality of surface electrodes 30D. In the present modification, five surface electrodes 30D are formed in accordance with the five emitters 130, so that one zener diode 20 (five in total) is mounted on each of the five surface electrodes 30D. In this case, the Zener diode 20 is also subjected to junction down mounting so that the pn junction of the semiconductor laser array element 10 and the pn junction of the Zener diode 20 are opposite to each other, or the Zener diode 20 is mounted on the n-type substrate. A p-layer and a p + layer are used.

  As described above, according to the present modification, the surface electrode 30D and the Zener diode 20 are provided for each emitter 130 of the semiconductor laser array element 10. Therefore, the resistance component between each emitter 130 and the Zener diode 20 is reduced. It can be almost uniform. Therefore, the surge resistance of the entire semiconductor laser device 2D can be further improved.

  The semiconductor laser device 2D according to the present modification and the semiconductor laser device 2 shown in FIG. 6 have the same configuration except for the above. In the present modification, the surface electrode 30D is separated into a plurality corresponding to each of the plurality of emitters 130. However, the present invention is not limited to this, and the surface electrode 30D is separated into a plurality corresponding to some of the plurality of emitters 130. May be. That is, the number of surface electrodes 30D and the number of emitters 130 (ridge portions 140) may not be the same. For example, when the number of surface electrodes 30D is smaller than the number of emitters 130, a plurality of electrodes corresponding to the plurality of emitters 130 are connected to one surface electrode 30D of the plurality of surface electrodes 30D.

(Modification 5 of Embodiment 2)
Next, a semiconductor laser device 2E according to Modification 5 of Embodiment 2 will be described with reference to FIG. FIG. 12 is a perspective view showing a configuration of a main part of a semiconductor laser device 2E according to Modification 5 of Embodiment 2.

  As shown in FIG. 12, in the semiconductor laser device 2E according to the present modification, one Zener diode 20E is provided behind the semiconductor laser array element 10 as in the semiconductor laser device 2B according to Modification 2 shown in FIG. Has been placed.

  The semiconductor laser device 2E according to the present modification example and the semiconductor laser device 2B according to the modification example 2 shown in FIG.

  Specifically, the Zener diode 20E according to the present modification has a concave curved end surface 20a facing the second end surface 10b (rear end surface) of the semiconductor laser array element 10. In this modification, the top view shape of the end face 20a of the Zener diode 20E is an arc shape as shown in FIG. 13A.

  Thus, by making the end surface 20a of the Zener diode 20E an arc-shaped curved surface, the distance between each emitter 130 of the semiconductor laser array element 10 and the Zener diode 20E can be made uniform. The resistance component between each emitter 130 and the Zener diode 20E can be made uniform. Thereby, the surge resistance of the entire semiconductor laser device 2E can be improved.

  Here, as shown in FIG. 13A, the radius of curvature of the arc of the end face 20a of the Zener diode 20E is R, and the distance between the center emitter and the outermost emitter among the five emitters 130 of the semiconductor laser array element 10 is set as follows. Assuming that a is the distance between the outermost emitter and the Zener diode 20E, and b is the distance between the center emitter and the Zener diode 20E, the following relational expression (Formula 1) is obtained by geometric calculation. Is guided.

  b = R−a / sin {arctan [a / (R−c)]} (Formula 1)

  Here, when α = a / c, β = R / c, and γ = b / c, (Expression 1) is expressed by the following relational expression (Expression 2).

  γ = β−α / sin {arctan [α / (β−1)]} (Formula 2)

  If this (formula 2) is represented by a graph, it is represented by the curve shown in FIG. 13B. As shown in FIG. 13B, it can be seen that the larger the value of a, the larger the radius of curvature R is required. At this time, making the distances between the emitters 130 and the Zener diodes 20E substantially uniform is considered to satisfy 0.9 ≦ γ ≦ 1. Substituting this into (Expression 2) yields the following relational expression (Expression 3).

  0.9 ≦ β−α / sin {arctan [α / (β−1)]} ≦ 1 (Formula 3)

Therefore, by designing the radius of curvature R of the end face 20a of the Zener diode 20E so as to satisfy this (Equation 3), the distance between each emitter 130 and the Zener diode 20E can be made substantially uniform. For example, as shown in FIG. 13B, when α = 0.5, β ≧ 2.2, and when α = 1, β ≧ 6, and α
In the case of 1.5, the design should be such that β ≧ 13.

  Here, in this modified example, as in the first embodiment, the emitter spacing of the five emitters 130 is 200 μm, and therefore a = 400 μm. At this time, if c = 600 μm, α = c / a = 1.5, and β ≧ 13 should be satisfied. That is, since β = R / c ≧ 13, R ≧ 13 × r = 13 × 600 μ = 7800 μm.

  Therefore, in this modification, a Zener diode 20E having an end face 20a having a radius of curvature R = 1 cm (10,000 μm) was produced. The arc-shaped end face 20a can be manufactured by, for example, subjecting the end face of the element to focused ion beam processing after the element is separated from the wafer and separated into individual pieces.

  The semiconductor laser device 2E according to this modification and the semiconductor laser device 2 shown in FIG. 6 have the same configuration in the shape of the Zener diode 20.

(Modification 6 of Embodiment 2)
Next, a semiconductor laser device 2F according to Modification 6 of Embodiment 2 will be described with reference to FIG. FIG. 14 is a perspective view showing the configuration of the main part of a semiconductor laser device 2F according to Modification 6 of Embodiment 2.

  As shown in FIG. 14, in the semiconductor laser device 2F according to the present modification, one Zener diode 20F is provided behind the semiconductor laser array element 10 in the same manner as the semiconductor laser device 2B according to Modification 2 shown in FIG. Has been placed.

  The semiconductor laser device 2F according to the present modification and the semiconductor laser device 2B according to the second modification shown in FIG. 9 are different in the shape of the Zener diode.

  Specifically, the Zener diode 20F in the present modification is elongated, and when the direction orthogonal to the front of the semiconductor laser array element 10 is the lateral direction, the lateral length of the Zener diode 20F is the semiconductor laser. It is longer than the length of the array element 10 in the horizontal direction. That is, the element width of the Zener diode 20F is longer than the element width of the semiconductor laser array element 10. That is, when the lateral length (element width) of the semiconductor laser array element 10 is W1, and the lateral length (element width) of the Zener diode 20F is W2, the relational expression of W1 ≦ W2 is satisfied. In the present modification, as in the first embodiment, the lateral length W1 of the semiconductor laser array element 10 is 1200 μm, so the lateral length W2 of the Zener diode 20F is 1500 μm.

  Further, the Zener diode 20F is disposed such that both end portions in the element width direction (lateral direction) of the Zener diode 20F protrude from both end portions in the element width direction (lateral direction) of the semiconductor laser array element 10. Yes.

  Thus, according to the semiconductor laser device 2F according to the present modification, the lateral length of the Zener diode 20F is longer than the lateral length of the semiconductor laser array element 10, so that the semiconductor laser array element 10 The difference in the resistance component in the oblique direction between each emitter 130 and the Zener diode 20F can be suppressed. Thereby, since the resistance component between each emitter 130 and Zener diode 20F can be equalized about each emitter 130, the surge resistance of the whole semiconductor laser apparatus 2F can be improved.

  The semiconductor laser device 2F according to the present modification and the semiconductor laser device 2 shown in FIG.

(Modification 7 of Embodiment 2)
Next, a semiconductor laser device 2G according to Modification 7 of Embodiment 2 will be described with reference to FIG. FIG. 15 is a perspective view showing a configuration of a main part of a semiconductor laser device 2G according to the modification 7 of the second embodiment.

  As shown in FIG. 15, in the semiconductor laser device 2G according to the present modification, one Zener diode 20G is provided behind the semiconductor laser array element 10 in the same manner as the semiconductor laser device 2B according to Modification 2 shown in FIG. Has been placed.

  The distance between the Zener diode and the semiconductor laser array element 10 is different between the semiconductor laser device 2G according to this modification and the semiconductor laser device 2B according to Modification 2 shown in FIG.

  Specifically, in the semiconductor laser device 2G according to the present modification, the distance between the Zener diode 20G and the semiconductor laser array element 10 is reduced as compared with the semiconductor laser device 2B according to Modification 2 shown in FIG. . In this case, as shown in FIG. 15, the Zener diode 20G and the semiconductor laser array element 10 may be disposed close to each other, or the Zener diode 20G and the semiconductor laser array element 10 are disposed in close contact with each other. Also good.

  By doing in this way, the difference of the resistance component of the diagonal direction between each emitter 130 of the semiconductor laser array element 10 and the Zener diode 20G can be suppressed. Thereby, since the resistance component between each emitter 130 and Zener diode 20G can be equalized about each emitter 130, the surge resistance of the whole semiconductor laser apparatus 2G can be improved.

  The semiconductor laser device 20G in the present modification example is not only different in the distance between the zener diode 20G and the semiconductor laser array element 10 from the semiconductor laser device 2B in the modification example 2 shown in FIG. The shape of 20G is also different. Specifically, the element width of the Zener diode 20G is made substantially the same as the element width of the semiconductor laser array element 10. The element width of the Zener diode 20G may not be the same as the element width of the semiconductor laser array element 10.

  In the present modification, the Zener diode 20G and the semiconductor laser array element 10 are brought close to or in close contact with each other. In this case, if the laser light leaks from the second end face (rear end face) of the semiconductor laser array element 10 and enters the Zener diode 20G, the Zener diode 20G may malfunction. In addition, an electron / hole pair is formed by the laser light absorbed in the Zener diode 20G and a current may flow, but this current is a reactive current. In other words, the absorption of the laser light by the Zener diode 20G is equivalent to a decrease in the efficiency of the semiconductor laser array element 10.

For this reason, as shown in FIG. 16A, a light incident prevention film 21 that suppresses the incidence of laser light may be formed on the side surface of the Zener diode 20G on the semiconductor laser array element 10 side. As the light incident preventing film 21, a highly reflective film (reflectance> 90%) made of an interference film in which two pairs of alumina (Al ₂ O ₃ ) and amorphous silicon are laminated with an optical length λ / 4 can be used. Note that λ is the center wavelength of the semiconductor laser array element 10.

In the case where the Zener diode 20G and the semiconductor laser array element 10 are brought into close contact with each other, the light incident prevention film 21 is preferably insulative in order to suppress leakage current. In this case, as the light incident prevention film 21, for example, a multilayer film of alumina (Al ₂ O ₃ ) and titanium oxide (TiO ₂ ) may be used.

  When the height of the emitter 130 serving as the light emitting point of the semiconductor laser array element 10 is higher than the height of the upper surface of the Zener diode 20G, the amount of laser light irradiated on the upper surface of the Zener diode 20G increases. Therefore, as shown in FIG. 16B, the light incidence preventing film 21 may be formed on the upper surface of the Zener diode 20G.

  Further, the light incident prevention film 21 may be formed on both the upper surface and the end surface of the Zener diode 20G, not on either the upper surface or the end surface (side surface) of the Zener diode 20G. In this case, it may be formed not only on the end face of the Zener diode 20G facing the semiconductor laser array element 10, but also on the end face opposite to this end face. Thus, by forming the light incident preventing film 21 on the surface of the Zener diode 20G, it is possible to more effectively block the laser light incident on the Zener diode 20G.

  The light incidence preventing film 21 formed in this way is not limited to the present modification, and may be applied to other modifications of the first and second embodiments. As a result, laser light incident on the Zener diode can be more effectively blocked, and malfunction of the Zener diode can be suppressed.

  Note that the position and shape of the Zener diode 20 are the same in the semiconductor laser device 2G according to this modification and the semiconductor laser device 2 shown in FIG.

(Embodiment 3)
Next, projector 200 according to Embodiment 3 will be described with reference to FIG. FIG. 17 is a schematic diagram of projector 200 according to the third embodiment.

  As shown in FIG. 17, the projector 200 is an example of an image display device using a semiconductor laser device. In the projector 200 according to the present embodiment, as a light source, for example, there are a semiconductor laser device 201R that emits red laser light, a semiconductor laser device 201G that emits blue laser light, and a semiconductor laser device 201B that emits green laser light. Used. In addition, as the semiconductor laser device 201R, the semiconductor laser device 201G, and the semiconductor laser device 201B, for example, the semiconductor laser device in the first or second embodiment is used.

  The projector 200 includes a lens 210R, a lens 210G and a lens 210B, a mirror 220R, a dichroic mirror 220G and a dichroic mirror 220B, a spatial modulation element 230, and a projection lens 240.

  The lens 210R, the lens 210G, and the lens 210B are, for example, collimating lenses, and are disposed in front of the semiconductor laser device 201R, the semiconductor laser device 201G, and the semiconductor laser device 201B, respectively.

  The mirror 220R reflects the red laser light emitted from the semiconductor laser device 201R. The dichroic mirror 220G reflects the green laser light emitted from the semiconductor laser device 201G and transmits the red laser light emitted from the semiconductor laser device 201R. The dichroic mirror 220B reflects the blue laser light emitted from the semiconductor laser device 201B, transmits the red laser light emitted from the semiconductor laser device 201R, and transmits the blue laser light emitted from the semiconductor laser device 201B. To do.

  The spatial modulation element 230 is configured to output red laser light from the semiconductor laser device 201R, green laser light from the semiconductor laser device 201G, and blue laser light from the semiconductor laser device 201B in accordance with an input image signal input to the projector 200. Are used to form a red image, a green image, and a blue image. As the spatial modulation element 230, for example, a liquid crystal panel or a DMD (digital mirror device) using a MEMS (microelectric mechanical system) can be used.

  The projection lens 240 projects the image formed by the spatial modulation element 230 onto the screen 250.

  In the projector 200 configured as described above, the laser light emitted from the semiconductor laser device 201R, the semiconductor laser device 201G, and the semiconductor laser device 201B is made almost parallel by the lens 210R, the lens 210G, and the lens 210B, and then the mirror 220R. Then, the light enters the dichroic mirror 220G and the dichroic mirror 220B.

  The mirror 220R reflects the red laser light emitted from the semiconductor laser device 201R in the 45 ° direction. The dichroic mirror 220G transmits the red laser light from the semiconductor laser device 201R reflected by the mirror 220R and reflects the green laser light emitted from the semiconductor laser device 201G in the 45 ° direction. The dichroic mirror 220B transmits the red laser light from the semiconductor laser device 201R reflected by the mirror 220R and the green laser light from the semiconductor laser device 201G reflected by the dichroic mirror 220G and is emitted from the semiconductor laser device 201B. The blue laser beam is reflected in the 45 ° direction.

  The red, green, and blue laser beams reflected by the mirror 220R, the dichroic mirror 220G, and the dichroic mirror 220B are incident on the spatial modulation element 230 in a time-sharing manner (for example, red → green → blue are sequentially switched at a period of 120 Hz). In this case, the spatial modulation element 230 displays a red image when the red laser beam is incident, displays a green image when the green laser beam is incident, and emits the blue laser beam. When incident, a blue image is displayed.

  As described above, the red, green, and blue laser lights that have undergone spatial modulation by the spatial modulation element 230 become red images, green images, and blue images, and are projected onto the screen 250 through the projection lens 240. In this case, each of the red image, the green image, and the blue image projected onto the screen 250 in a time-sharing manner is a single color, but since it is switched at high speed, the human eye has an image of a mixed color, That is, it is recognized as a color image.

  As described above, in the projector 200 in the present embodiment, the semiconductor laser array element or the semiconductor laser device in the first to fifth embodiments is used as the semiconductor laser device 201R, the semiconductor laser device 201G, and the semiconductor laser device 201B. That is, a semiconductor laser device is used that can emit a plurality of laser beams without conspicuous speckle noise and without reducing color purity.

  Thereby, speckle noise does not occur at the center of the screen 250. Further, even if speckle noise occurs due to laser beam interference, it occurs at a position away from the center of the screen 250. Therefore, speckle noise is less likely to be felt by a person viewing the image projected on the screen 250. In addition, since the color purity is increased, the vividness of the image projected on the screen 250 is not deteriorated.

(Modification)
Although the semiconductor laser device according to the present disclosure has been described based on the embodiments, the present disclosure is not limited to the above embodiments.

  For example, in the first and second embodiments, a multi-emitter semiconductor laser device is configured by using a monolithic semiconductor laser element in which a plurality of light emitting portions (emitters) are formed in one semiconductor laser array element. As shown in FIG. 18, a multi-emitter semiconductor laser device 1A is formed by using a plurality of semiconductor laser elements 10A in which one light emitting portion (emitter) is formed in one semiconductor laser array element to form a hybrid structure. It may be configured. That is, a multichip array constituted by a plurality of semiconductor laser elements 10A may be used. When such a multichip array is used, each semiconductor laser element can be oscillated at different wavelengths by producing each semiconductor laser element with a different semiconductor composition. For example, in the case of a projector red light source, the oscillation wavelengths of five semiconductor laser elements are set to 656 nm, 658 nm, 660 nm, 662 nm, and 664 nm. The spectrum can be widened and the coherence can be reduced. As a result, the generation of speckle noise can be suppressed and a good image can be obtained. Also in such a multi-chip array semiconductor laser device 1A, surge resistance can be improved by mounting the Zener diode 20 on the submount 40 on which the plurality of semiconductor laser elements 10A are mounted.

In the first and second embodiments, the semiconductor laser array element 10 that emits red laser light is used. In the first and second embodiments, the semiconductor laser array element that emits blue laser light is used. May be. A semiconductor laser array element that emits blue laser light uses, for example, a GaN substrate as the substrate 120, and the laser array unit 110 is formed of Al _x Ga _y In _1-xy N (where 0 ≦ x, y ≦ 1). And 0 ≦ x + y ≦ 1.) The semiconductor material may be made of a group III nitride semiconductor represented by: Specifically, an n-type GaN substrate is used as the substrate 120, n-Al _0.2 Ga _0.8 N is used as the first cladding layer 111, u-GaN is used as the first guide layer 112, and the active layer 113 is used. U-In _0.18 Ga _0.82 N is used as the second guide layer 114, u-GaN is used as the second cladding layer 114, p-Al _0.2 Ga _0.8 N is used as the second cladding layer 115, and the contact layer 116 is used. P-GaN can be used.

In the first and second embodiments, a semiconductor laser array element that emits green laser light may be used. A semiconductor laser array element that emits green laser light uses, for example, a GaN substrate as the substrate 120, and the laser array unit 110 is replaced with Al _x Ga _y In _1-xy N (where 0 ≦ x, y ≦ 1). And 0 ≦ x + y ≦ 1.) The semiconductor material may be made of a group III nitride semiconductor represented by: Specifically, an n-type GaN substrate is used as the substrate 120, n-Al _0.2 Ga _0.8 N is used as the first cladding layer 111, u-GaN is used as the first guide layer 112, and the active layer 113 is used. U-In _0.3 Ga _0.7 N is used, u-GaN is used as the second guide layer 114, p-Al _0.2 Ga _0.8 N is used as the second cladding layer 115, and the contact layer 116. P-GaN can be used.

  In the first and second embodiments, the semiconductor laser array element 10 having the ridge waveguide structure having the ridge portion 140 is used. However, the present invention is not limited to this.

  Specifically, as shown in FIG. 19, a semiconductor laser array element 10B in which no ridge portion is formed may be used. In the semiconductor laser array element 10B, the emitter 130 is formed only by the divided first electrodes 151a and 151. The semiconductor laser array element 10B configured in this manner is called a gain waveguide type because the difference in the refractive index in the horizontal direction of the emitter 130 is given by the difference in the imaginary part of the refractive index caused by the gain due to current injection. The gain-guided semiconductor laser array element has a simple structure and can manufacture the laser array unit 110 at a lower cost than the refractive index-guided semiconductor laser array element.

  As another example of the semiconductor laser array element in which the ridge portion is not formed, the semiconductor laser array element 10C having the structure shown in FIG. 20 may be used. In the semiconductor laser array element 10 </ b> C, after dividing the second cladding layer 115, a buried layer 117 is formed between the adjacent second cladding layers 115. The buried layer 117 has a conductivity type different from that of the second cladding layer 115 and has a refractive index lower than that of the second cladding layer 115. The contact layer 116 is formed on the entire surface of the second cladding layer 115 and the buried layer 117 across the second cladding layer 115 and the buried layer 117. The first electrode 151 is also formed on the entire surface of the contact layer 116. Due to the difference in conductivity type between the second cladding layer 115 (eg, p-type semiconductor layer) and the buried layer 117 (eg, n-type semiconductor layer), a reverse bias is applied to the pn junction in the operating state, and the buried layer 117 has No current flows, and the injected current is confined only to the second cladding layer 115. Thereby, the light generated in the active layer 113 is confined by the refractive index difference between the second cladding layer 115 and the buried layer 117 in the horizontal direction of the substrate. That is, the semiconductor laser array element 10 </ b> C in the present modification is a refractive index waveguide type, similar to the semiconductor laser array element 10 in the first embodiment. The semiconductor laser array element 10 </ b> C configured in this way has a large contact area between the contact layer 116 and the first electrode 151, so that low contact resistance (in other words, low voltage operation) is possible.

In the semiconductor laser array element 10C of the present modification shown in FIG. 20, the embedded layer 117 is n- (Al ₀₎ when applied to the semiconductor laser array element that emits red laser light according to the first embodiment. _.6 Ga _0.4 ) _0.5 In _0.5 P. Further, when applied to a semiconductor laser array element that emits blue laser light and when applied to a semiconductor laser array element that emits green laser light, the buried layer 117 can be made of n-GaN.

  Further, the semiconductor laser array elements 10B and 10C shown in FIGS. 19 and 20 are exemplified as the semiconductor laser array elements in which the ridge portion is not formed, but the semiconductor laser array elements in which the ridge portion is not formed are other than these. In addition, a vertical cavity surface emitting laser (VCSEL) or the like may be used.

  In the first and second embodiments, the number of the ridge portions 140 is five, but is not limited thereto. For example, the number of ridge portions 140 may be six or more. That is, the number of emitters 130 is not limited to five. For example, the number of ridges 140 and emitters 130 may be 20. As a result, a high-power (for example, 100 W class) semiconductor laser array element greatly exceeding 1 W can be realized.

  In the third embodiment, the case where the semiconductor laser device in the first and second embodiments is used as the light source of the projector is exemplified. However, the semiconductor laser device in the first and second embodiments is limited to the light source of the projector. Instead, you may use for the light source of another apparatus. For example, it can be used as a light source of a laser processing apparatus.

  In addition, the configurations and functions in each of the first and second embodiments can be arbitrarily set without departing from the gist of the present disclosure, and the modes obtained by making various modifications conceived by those skilled in the art with respect to the first and second embodiments. A form realized by combination is also included in the present disclosure.

  The semiconductor laser device according to the present disclosure can be used as a light source of various devices such as an image display device such as a projector or a laser processing device, and is particularly useful as a light source of a device that requires a relatively high light output. It is.

1, 1A, 2, 2A, 2B, 2C, 2D, 2E, 2F, 2G, 201R, 201G, 201B Semiconductor laser device 10, 10B, 10C Semiconductor laser array element 10a First end face 10b Second end face 10A Semiconductor laser element 20 , 20E, 20F, 20G Zener diode 20E Zener diode 20a End face 21 Light incident prevention film 30, 30D Surface electrode 40 Submount 50 Heat sink block 50A Metal block 60 Package base 61a, 61b Lead pin 62 Low melting point glass 70 Cap 71 Window glass 81, 82, 83 Wire 110 Laser array section 111 First cladding layer 112 First guide layer 113 Active layer 114 Second guide layer 115 Second cladding layer 116 Contact layer 117 Buried layer 120 Substrate 130 D Jitter 140 ridges 151,151a first electrode 152 second electrode 160 insulating layer 200 projectors 210R, 210G, 210B lens 220R mirror 220G, 220B dichroic mirror 230 the spatial modulation element 240 the projection lens 250 Screen

Claims (12)

The base,
A laser element unit disposed above the base and having a plurality of light emitting units for emitting laser light;
A Zener diode disposed above the base and electrically connected to the laser element unit. A semiconductor laser device. Furthermore, a surface electrode formed on the upper surface of the base,
The semiconductor laser device according to claim 1, wherein the laser element section and the Zener diode are connected in parallel via the surface electrode. When the emission direction of the laser beam emitted from the laser element portion is the front, and the direction orthogonal to the front is the side,
The semiconductor laser device according to claim 1, wherein the Zener diode is disposed on the side of the laser element unit. The semiconductor laser device according to claim 3, wherein the Zener diode is disposed on both sides of the side of the laser element portion. When the emission direction of the laser light emitted from the laser element portion is the front and the direction opposite to the front is the rear,
The semiconductor laser device according to claim 1, wherein the Zener diode is disposed behind the laser element unit. The semiconductor laser device according to claim 5, wherein an end surface of the Zener diode on the laser element portion side is arcuate. The semiconductor laser device according to claim 5, wherein a length of the Zener diode in a direction orthogonal to the front is longer than a direction orthogonal to the front of the laser element unit. The surface electrode is electrically separated into a plurality corresponding to each of the plurality of light emitting portions or corresponding to some of the plurality of light emitting portions,
The semiconductor laser device according to claim 2, wherein a plurality of the Zener diodes are arranged according to the plurality of separated surface electrodes. The semiconductor laser device according to claim 1, wherein the laser element unit and the Zener diode are connected in parallel by a metal block disposed on the side opposite to the base. The semiconductor laser device according to claim 1, wherein the laser element unit is a semiconductor laser array element having the plurality of light emitting units on the same substrate. The semiconductor laser device according to claim 1, wherein the laser element unit is configured by a plurality of semiconductor laser elements. The semiconductor laser device according to claim 1, wherein the laser element unit and the Zener diode are housed in one package.

Images