JP6091926B2 - Semiconductor light emitting device - Google Patents

Description

  The present invention relates to a semiconductor light emitting device, and more particularly to a semiconductor light emitting device including a semiconductor laser element and a wavelength conversion member that converts the wavelength of laser light from the semiconductor laser element.

  Conventionally, as this type of semiconductor light-emitting device, for example, one having a structure as shown in FIG.

  The pedestal 80 is constituted by a lead electrode 81, a pedestal bottom portion 82 having the lead electrode 81, and a pedestal column portion 83 provided on the pedestal bottom portion 82, and the side surface of the pedestal column portion 83 is interposed with an adhesive member. A semiconductor laser element 84 is mounted. On the upper surface of the pedestal bottom portion 82, a bottomed cylindrical shape that extends in the vertical direction from the periphery of the upper surface of the pedestal bottom portion 82 so as to cover the pedestal column portion 83 and the semiconductor laser element 84 mounted on the pedestal column portion 83. The cap (made of metal) 85 is adhered and fixed.

  The cap upper portion 86 is provided with a through hole 87, and a wavelength conversion member 88 is mounted on the upper surface of the through hole 87 by eutectic bonding or via an adhesive so as to cover the through hole 87. The through-hole 87 is positioned so that its central axis substantially overlaps the outgoing optical axis of the semiconductor laser element 84.

  As a result, the laser light emitted from the semiconductor laser element 84 passes through the through-hole 87 of the cap 85 and is irradiated to the wavelength conversion member 88, and the light converted into the wavelength converted by the wavelength conversion member 88 and the light (laser not converted). Light) is emitted from the wavelength conversion member 88, and the mixed color light is irradiated to the outside.

JP 2011-14587 A

  By the way, in the semiconductor light emitting device of Patent Document 1 described above, for example, when the wavelength conversion member 88 is detached from the cap upper portion 86 in an environment where external strong vibration or impact is received, the laser light emitted from the semiconductor laser element 84 is emitted. The light passes through the through hole 87 and is irradiated to the outside as it is. As a result, when the semiconductor light-emitting device is used as a light source for a lighting device or a display device, there is a risk that the safety (eye safety) for the eyes of the viewer is impaired.

  Therefore, the present invention was devised in view of the above problems, and an object thereof is a semiconductor light emitting device including an optical system that irradiates laser light from a semiconductor laser element to the outside through a wavelength conversion member. Even if the wavelength conversion member is detached from the optical system for some reason, a configuration capable of reliably ensuring eye safety for the viewer is realized.

In order to solve the above-described problem, the invention described in claim 1 of the present invention includes a semiconductor laser element having a pair of electrodes, and a semiconductor laser element that covers the semiconductor laser element and allows light from the semiconductor laser element to pass through. A protective cap having a light-transmitting window formed so as to close the first through-hole and the first through-hole, and a second for allowing light from the semiconductor laser element to pass through the protective cap. A circuit pattern forming substrate in which a through hole is formed; and a laser beam radiated from the semiconductor laser element and disposed so as to close the second through hole of the circuit pattern forming substrate. in is excited with a phosphor plate made by mixing phosphor particles in glass or light transmitting ceramic emits fluorescence, and the the phosphor plate the semiconductor laser Child are conductors formed anywhere other than the portion to be irradiated, wherein is connected the circuit pattern formed on the circuit pattern electrically formed on the substrate, the semiconductor laser device, Power is supplied from the power source to the pair of electrodes via the conductor and the circuit pattern on the circuit pattern forming substrate .

  In the invention described in claim 2 of the present invention, in claim 1, the conductor includes a metal film formed of any one of Ag, Ag alloy, Al, Al alloy, Rh, and Rh alloy. It is characterized by.

  In addition, the invention described in claim 3 of the present invention further comprises a substrate and a circuit pattern formed on one surface of the substrate in claim 1 or 2, wherein the circuit pattern and The conductor is electrically connected by any one of a bump, a eutectic metal, and solder.

  The invention described in claim 4 of the present invention is characterized in that, in claim 3, the substrate is formed of any one of AlN, alumina, SiC, and SiN.

  A semiconductor light emitting device of the present invention is provided with a first circuit having a semiconductor laser element, a semiconductor pattern that is positioned in the direction of laser light emission of the semiconductor laser element, has a conductor pattern, and converts the wavelength of the laser light from the semiconductor laser element to the outside. A second circuit having a phosphor plate that irradiates toward the semiconductor laser element is connected to form a current-carrying path for the semiconductor laser element. If the phosphor plate is detached, the current-carrying path to the semiconductor laser element is cut and the semiconductor is The oscillation of the laser element stops and the emission of laser light stops.

  As a result, the laser beam is prevented from directly entering the eyes of the viewer. Thereby, the eye safety for the viewer can be reliably ensured.

It is a top view of the semiconductor light-emitting device of an embodiment. It is AA sectional drawing of FIG. It is explanatory drawing of a circuit pattern formation board | substrate. It is a top view of a fluorescent substance plate with a reflective electrode. It is BB sectional drawing of FIG. It is sectional explanatory drawing of the mounting method of the fluorescent substance plate with a reflective electrode. It is a drive circuit diagram of a semiconductor laser element. It is a ray tracing figure of a laser beam. It is explanatory drawing of the detached state of the fluorescent substance plate with a reflective electrode. It is sectional explanatory drawing of the fluorescent substance plate with a reflective electrode. Similarly, it is sectional explanatory drawing of the fluorescent substance plate with a reflective electrode. It is explanatory drawing of a prior art example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 11 (the same parts are given the same reference numerals). The embodiments described below are preferable specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. Unless stated to the effect, the present invention is not limited to these embodiments.

  FIG. 1 is a plan view of the semiconductor light emitting device of this embodiment, and FIG. 2 is a cross-sectional view taken along the line AA of FIG.

  As shown in FIGS. 1 and 2, the semiconductor light emitting device 30 of the present embodiment is provided with a pair of through holes 1 a and 1 b in a disk-shaped base 1 made of metal, and a pair of through holes 1 a and 1 b. The metal lead electrodes 2 and 3 are inserted and fixed in an electrically insulated state.

  A metal-made columnar heat sink 4 is mounted on the upper surface 1c of the pedestal 1, and a semiconductor laser element 5 is adhered and fixed to a side surface of the heat sink 4 via a heat conductive insulating adhesive (not shown). Yes. The semiconductor laser element 5 has a pair of element electrodes (not shown), and each element electrode is formed on the pedestal 1 of the lead electrodes 2 and 3 by a conductive connecting member (not shown) such as a metal wire. It is electrically connected to the protruding portions 2a and 3a protruding from the upper surface 1c.

  The upper surface 1c of the pedestal 1 is further provided with a through hole in the upper center so as to cover the heat sink 4, the semiconductor laser element 5 adhered and fixed to the heat sink 4, and the protruding portions 2a and 3a of the pair of lead electrodes 2 and 3, respectively. A metal protective cap 6 made of metal provided with 6a is attached.

  A glass window 7 is attached to the upper inner surface 6 c of the protective cap 6 so as to close the through hole 6 a of the protective cap 6. The glass window 7 has a function of transmitting laser light emitted from the semiconductor laser element 5 and at the same time preventing external foreign matters such as moisture, dust and gas from entering the protective cap 6 through the through hole 6a. doing.

  As described above, the pedestal 1, the pair of lead electrodes 2 and 3, the heat sink 4, the semiconductor laser element 5, the protective cap 6 and the glass window 7 constitute a semiconductor laser 8.

On the upper upper surface 6b of the protective cap 6 constituting the semiconductor laser 8, a disc-shaped circuit pattern forming substrate 10 provided with a through hole 10a in the center is mounted. The circuit pattern forming substrate 10 has a base portion 10d formed of AlN (aluminum nitride) and a pair of circuit patterns 10b and 10c that are electrically separated from each other on both sides of the through hole 10a. are (see FIG. 3 (illustration of the circuit pattern forming substrate)), the circuit pattern 10b with matching the central axis X ₁ of the through hole 10a to the central axis X ₂ of the through hole 6a of the protective cap 6, 10c is formed It is placed with its surface facing up.

  On the surface of the circuit pattern forming substrate 10 on which the circuit patterns 10b and 10c are formed, a phosphor plate with a reflective electrode so as to close the through hole 6a of the protective cap 6 and the through hole 10a of the circuit pattern forming substrate 10. 11 is implemented.

  As shown in FIG. 4 (plan view) and FIG. 5 (BB sectional view of FIG. 4), the phosphor plate 11 with a reflective electrode is a phosphor formed by mixing phosphor particles in glass or light-transmitting ceramic. A light reflecting electrode 11b made of Ag, Ag alloy, Al, Al alloy, Rh, Rh alloy having high light reflectivity and high electrical conductivity is formed on substantially the entire surface other than the center of one surface of the substrate 11a. Has a circular opening 11c in which the light reflecting electrode 11b is not formed, and the phosphor substrate 11a is exposed in the opening 11c.

When the phosphor plate 11 with a reflective electrode is mounted on the circuit pattern forming substrate 10, as shown in FIG. 6 (cross-sectional explanatory view of the mounting method of the phosphor plate with a reflective electrode), the opening of the phosphor plate 11 with the reflective electrode is opened. a central axis X ₃ parts 11c in a state of being aligned with the center axis X ₁ of the through hole 10a of the circuit pattern forming substrate 10, the circuit of the light reflective electrode 11b side and the circuit pattern forming substrate 10 of the reflective electrode with the phosphor plate 11 The patterns 10b and 10c are opposed to each other, and the light reflecting electrode 11b and the circuit patterns 10b and 10c are mechanically and electrically joined by Au bumps 12 to be mounted.

Accordingly, the central axis X ₁ of the through hole 10a of the circuit pattern forming substrate 10, the central axis X ₂ of the through hole 6a of the protective cap 6, and the central axis X ₃ of the opening portion 11c of the phosphor plate 11 with the reflecting electrode are all one. In addition, they are located on the same line and coincide with the optical axis of a semiconductor laser element (not shown).

  Further, referring back to FIGS. 1 and 2, the circuit pattern forming substrate 10 has a pair of external connection electrodes 13, 14 whose one end is electrically connected to each of the circuit patterns 10 b, 10 c of the circuit pattern forming substrate 10. Is extended.

  When the semiconductor light emitting device 30 having the above configuration is used as a light source of a lamp such as an illumination lamp or a display lamp, the circuit configuration with a peripheral circuit is configured as shown in FIG. 7 (semiconductor laser element drive circuit diagram). Thus, the semiconductor laser element 5 can be driven by supplying power.

  Specifically, one of the pair of lead electrodes 2 and 3 (for example, lead electrode 2) and one of the pair of external connection electrodes 13 and 14 (for example, external connection) The electrode 13) is electrically connected, and a driving voltage of the semiconductor laser element 5 is applied between the other lead electrode 3 and the other external connection electrode.

  In this case, when the lead electrode 3 is connected to the anode electrode of the semiconductor laser element 5 (the lead electrode 2 is connected to the cathode electrode), a voltage on the (+) side is applied to the lead electrode 3 and the external connection electrode 14 (−) Side voltage is applied to. On the contrary, when the lead electrode 3 is connected to the cathode electrode of the semiconductor laser element 5 (the lead electrode 2 is connected to the anode electrode), a voltage on the (−) side is applied to the lead electrode 3, and the external connection electrode 14. (+) Side voltage is applied to.

  In this embodiment, it is assumed that the lead electrode 3 is connected to the anode electrode of the semiconductor laser element 5, the lead electrode 2 is connected to the cathode electrode of the semiconductor laser element 5, and the (+) side voltage is applied to the lead electrode 3. Is applied, and a voltage on the (−) side is applied to the external connection electrode 14.

  Then, in order from the (+) output terminal of the power supply 20, the lead electrode 3, the semiconductor laser element 5, the lead electrode 2, the short bar 21 for electrically connecting the lead electrode 2 and the external connection electrode 13, the external connection electrode 13, The circuit pattern 10b of the circuit pattern forming substrate 10, the Au bump 12, the light reflecting electrode 11b of the phosphor plate 11 with the reflecting electrode, the Au bump 12, the circuit pattern 10c of the circuit pattern forming substrate 10, and the external connection electrode 14 are used. An energization path to the (−) output terminal is formed, and the drive current of the semiconductor laser element 5 flows through this energization path, and the semiconductor laser element 5 enters an oscillation state and emits laser light.

Laser light (for example, blue light having a wavelength of 450 nm) L ₁ emitted from the semiconductor laser element 5 passes through the glass window 7 and then passes through the protective cap 6 as shown in FIG. Through the through-hole 6a, the through-hole 10a of the circuit pattern forming substrate 10 and the opening 11c of the phosphor plate 11 with the reflecting electrode to reach the light incident surface 11aa of the phosphor substrate 11a exposed to the opening 11c. The light enters the phosphor substrate 11a from the incident surface 11aa.

  The blue laser light incident on the phosphor substrate 11a partially excites phosphor particles mixed in the phosphor substrate 11a, and is transmitted through the phosphor substrate 11a as it is from the light emitting surface 11ab. Color mixed light of the light and wavelength converted light that has been wavelength-converted by excitation of the phosphor particles is emitted.

  In this case, for example, if the phosphor particles mixed in the phosphor substrate 11a are yellow phosphor particles that are excited by blue light and converted into yellow light that is complementary to the blue light, Light of a hue close to white light can be obtained by additive color mixing with yellow light whose wavelength has been converted by exciting a portion of the blue laser light with the yellow phosphor particles.

  Instead of yellow phosphor particles, mixed phosphor particles of green phosphor particles that are excited by blue light and converted to green light and red phosphor particles that convert wavelength to red light are used. Of green light whose wavelength is converted by exciting a green phosphor particle and a part of blue laser light and red light whose wavelength is converted by exciting red phosphor particles White light can also be obtained by mixing colors.

  Furthermore, light of various hues other than white light can be obtained by appropriately combining the wavelength of the laser light and the type of phosphor particles.

  In addition, the wavelength conversion light by the laser beam and the phosphor particles in the phosphor substrate 11a of the phosphor plate 11 with the reflecting electrode is emitted from the direct light emitting surface 11ab to the outside, and light by internal reflection or scattering. Some of them are directed in directions other than the exit surface 11ab.

Among them, the light traveling toward the light reflecting electrode 11b by internal reflection or scattering is reflected by the light reflecting electrode 11b, and the reflected light is emitted to the outside from the light emitting surface 11ab. In other words, the light quantity of the outgoing light L ₂ from the light emitting surface 11ab is increased by providing the light-reflection electrode 11b which serves as a light reflecting function and electrode function on the reflective electrode with phosphor plate 11, the light use efficiency of Can be improved.

  By the way, in the semiconductor light emitting device 30 having the above configuration, when the phosphor plate 11 with the reflecting electrode is detached from the circuit pattern forming substrate 10 for some reason such as strong external vibration or impact, power is supplied to the semiconductor laser element 5. Accordingly, the reflecting electrode-equipped phosphor plate 11 constituting a part of the energization path is removed from the energization path, whereby the energization path is interrupted and the energization to the semiconductor laser element 5 is stopped to supply power. Is cut off, the oscillation of the semiconductor laser element 5 stops and the emission of the laser light stops (see FIG. 9 (an explanatory diagram of the detached state of the phosphor plate with a reflective electrode)).

  Moreover, even if the phosphor plate 11 with a reflective electrode does not come off, the light reflective electrode 11b may be broken by the entry of a flack. This is also the same in that the laser beam is prevented from leaking directly to the outside through the crack by cutting the energization path.

  That is, it is assumed that the phosphor plate 11 with a reflecting electrode that constitutes a part of the optical system until the laser beam emitted from the semiconductor laser element 5 is irradiated outward is optically detached from the circuit pattern forming substrate 10. At the same time, an electrical circuit cut state is formed, the emission of the laser light from the semiconductor laser element 5 is stopped, and the laser light is prevented from directly entering the eyes of the viewer. Thereby, the eye safety for the viewer can be reliably ensured.

  In addition to the above configuration, the reflecting electrode-equipped phosphor plate 11 is mixed with glass or light-transmitting ceramic on one side with a transparent or scattering plate 25 sandwiched between them as shown in FIG. 10 (cross-sectional view). It is good also as a structure which provided the fluorescent substance substrate 11a formed in this way, and formed the light reflection electrode 11b except the center opening part 11c in the other side.

  As a result, the laser light that has passed through the opening 11c of the light reflecting electrode 11b and entered the transparent or scattering plate 25 is diffused and scattered by the transparent or scattering plate 25 and then enters the phosphor substrate 11a. Therefore, light with less luminance unevenness is emitted from the phosphor substrate 11a toward the outside.

  Alternatively, as shown in FIG. 11 (cross-sectional view), a transparent or scattering plate 25 is provided on one side across the phosphor substrate 11a, and the light reflecting electrode 11b is formed on the other side except for the central opening 11c. It is good also as a structure.

  As a result, the light that passes through the opening 11c of the light reflecting electrode 11b, enters the phosphor substrate 11a, is guided through the phosphor substrate 11a, and is emitted is diffused and scattered by the transparent or scattering plate 25 to obtain luminance. Light with less unevenness is emitted toward the outside. At the same time, the transparent or scattering plate 25 contributes to heat dissipation of the phosphor substrate 11a heated by irradiation with the laser light. Therefore, a decrease in the fluorescence characteristics of the phosphor particles is suppressed, and a decrease in the amount of emitted light is suppressed.

  The electrical connection between the light reflecting electrode 11b of the phosphor plate 11 with the reflecting electrode and each of the circuit patterns 10b and 10c of the circuit pattern forming substrate 10 is not limited to the Au bump 12 described above. Bonding with AuSn eutectic or solder may be used.

  Moreover, the base material part of the circuit pattern formation board | substrate 11 is not restricted to AlN (aluminum nitride), For example, it forms with an alumina ceramic with favorable heat conductivity, SiC (silicon carbide), SiN (silicon nitride). It is also possible.

  Further, the light reflecting electrode 11b of the phosphor plate 11 with a reflecting electrode may be formed in a multilayer structure in order to improve the bonding property of the bonding member connecting the circuit patterns 10b and 10c of the circuit pattern forming substrate 10. Is possible. In that case, for example, a three-layer structure of Ag / TiW / Au is used, the side having a reflecting function is Ag, and the joining side of the joining member is Au.

  Moreover, the opening part 11c in which the light reflection electrode 11b is not formed of the phosphor plate 11 with the reflection electrode is not limited to the circular shape, and may be a triangle, a quadrangle, or another polygon.

DESCRIPTION OF SYMBOLS 1 ... Base 1a ... Through-hole 1b ... Through-hole 1c ... Upper surface 2 ... Lead electrode 2a ... Projection part 3 ... Lead electrode 3a ... Projection part 4 ... Heat sink 5 ... Semiconductor laser element 6 ... Protection cap 6a ... Through-hole 6b ... Upper upper surface 6c ... Upper inner surface 7 ... Glass window 8 ... Semiconductor laser 10 ... Circuit pattern forming substrate 10a ... Through hole 10b ... Circuit pattern 10c ... Circuit pattern 10d ... Base material 11 ... Phosphor plate 11a with reflecting electrode 11a ... Phosphor substrate 11aa ... Light incident surface 11ab ... Light emitting surface 11b ... Light reflecting electrode 11c ... Opening 12 ... Au bump 13 ... External connection electrode 14 ... External connection electrode 20 ... Power supply 21 ... Short bar 25 ... Transparent or scattering plate 30 ... Semiconductor light emitting device

Claims (4)

A semiconductor laser element having a pair of electrodes;
A protective cap that covers the semiconductor laser element and includes a first through hole through which light from the semiconductor laser element passes and a translucent window formed so as to close the first through hole;
A circuit pattern forming substrate disposed on the protective cap and having a second through-hole for allowing light from the semiconductor laser element to pass through;
Glass or light transmission that is arranged in the radiation direction of the laser light emitted from the semiconductor laser element so as to close the second through hole of the circuit pattern forming substrate and is excited by the laser light to emit fluorescence. A phosphor plate formed by mixing phosphor particles in a ceramic ,
The phosphor plate is formed with a conductor at any place other than the portion irradiated with the semiconductor laser element,
The conductor is electrically connected to a circuit pattern formed on the circuit pattern forming substrate;
In the semiconductor laser device, power is supplied from a power source to the pair of electrodes via the conductor and a circuit pattern on the circuit pattern forming substrate .   The semiconductor light emitting device according to claim 1, wherein the conductor includes a metal film formed of any one of Ag, Ag alloy, Al, Al alloy, Rh, and Rh alloy.   And a circuit pattern formed on one surface of the substrate, wherein the circuit pattern and the conductor are electrically connected by any one of a bump, a eutectic metal, and solder. The semiconductor light-emitting device according to claim 1, wherein the light-emitting device is a semiconductor light-emitting device.   4. The semiconductor light emitting device according to claim 3, wherein the substrate is made of any one of AlN, alumina, SiC, and SiN.

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