JP7288221B2 - light emitting device - Google Patents

Description

The present invention relates to light emitting devices.

a base body, a semiconductor laser element fixed to the upper surface of the base body, a lid provided so as to surround the semiconductor laser element, a translucent member joined to the lid so as to block the through hole of the lid, is known. In this light emitting device, the lid body is formed with a curved portion having a substantially U-shaped cross section so as to surround the through hole when viewed from above. The curved portion absorbs the deformation due to the expansion of the lid, thereby preventing the translucent member from cracking (for example, FIG. 1 of Patent Document 1).

JP 2002-289958

In such a light emitting device, there is room for further reducing damage to the translucent member.

A light-emitting device according to an aspect of the present invention includes a base body having a main body portion, a frame portion provided on the upper surface of the main body portion and having an upper surface forming a first opening, and one or more laser elements provided on the upper surface of the main body; a support portion fixed to the upper surface of the frame and provided with a second opening inside the first opening of the frame; a light-transmitting portion provided to block an opening; and a lens body disposed on the support portion inside the first opening of the frame and above the light-transmitting portion. , provided.

FIG. 1 is a perspective view of a light emitting device according to an embodiment. FIG. 2 is a top view of the light emitting device according to the embodiment. FIG. 3 is a cross-sectional view along III--III in FIG. FIG. 4 is an enlarged view of the broken-line frame in FIG. 5 is a cross-sectional view taken along line VV of FIG. 2. FIG. FIG. 6 is a perspective view of a light emitting device including a light guide member and a lid. FIG. 7 is a cross-sectional view along VII-VII in FIG.

A mode for carrying out the present invention will be described below with reference to the drawings. However, the embodiments shown below are for embodying the technical idea of the present invention, and do not limit the present invention. Note that the sizes and positional relationships of members shown in each drawing may be exaggerated for clarity of explanation. In this specification, the light extraction surface side of the light emitting device (upper side in FIG. 3) is referred to as upper side, and the opposite side (lower side in FIG. 3) is referred to as lower side. A direction parallel to the direction in which the lead pins 13 extend is called the X direction, and a direction perpendicular to the direction in which the lead pins 13 extend is called the Y direction.

<Embodiment>
FIG. 1 shows a perspective view of a light emitting device 200 according to this embodiment, FIG. 2 shows a top view of the light emitting device 200, FIG. 3 shows a cross-sectional view along III-III in FIG. 2, and FIG. An enlarged view within a dashed frame is shown, and FIG. 5 shows a cross-sectional view taken along line VV of FIG.

As shown in FIGS. 1 to 5, the light emitting device 200 includes a base body 10 having a main body portion 11 and a frame portion 12 provided on the upper surface of the main body portion 11, and an upper surface of the main body portion 11 inside the frame portion 12. one or more laser elements 20 provided on the upper surface of the frame portion 12, a support portion 31 fixed to the upper surface of the frame portion 12 and provided with an opening inside the frame portion 12, and a light transmitting portion 32 provided so as to close the opening. and a lens body 40 arranged above the translucent portion 32 . At this time, the support portion 31 includes a first portion 31a fixed to the upper surface of the frame portion 12 and a lens body 40 provided inside the first portion 31a at a position lower than the first portion 31a. A second portion 31b and a third portion 31c provided at a position lower than the second portion 31b inside the second portion 31b, where the light transmitting portion 32 is disposed, and the light transmitting portion 32 and the lens A difference in thermal expansion coefficient from the body 40 is smaller than a difference in thermal expansion coefficient between the translucent portion 32 and the main body portion 11 .

According to the light emitting device 200, it is possible to reduce breakage of the translucent portion 32 sealing the space in which the laser element 20 is arranged. This point will be described in detail below.

Since a laser element generates heat more easily than a light-emitting diode element, the laser element is generally mounted on a main body made of a material with relatively high thermal conductivity. Materials with high thermal conductivity include, for example, metal materials such as copper, and these materials have relatively large coefficients of thermal expansion. That is, the main body tends to have a larger coefficient of thermal expansion than other members. Therefore, when the heat generated by driving the laser element is transferred to the main body, the main body expands and tends to spread outward, so the frame fixed to the main body also tends to spread outward, and the translucent part 32 is easily damaged.

Therefore, in the light emitting device 200, the support portion 31 included in the lid 30 includes a first portion 31a fixed to the upper surface of the frame portion 12 and a portion provided inside the first portion 31a at a position lower than the first portion 31a. a second portion 31b where the lens body 40 is arranged, and a third portion 31c where the translucent portion 32 is arranged, which is provided at a position lower than the second portion 31b inside the second portion 31b; I am using something that contains In other words, two or more steps are provided, and the lens body 40 is arranged in one step, and the translucent portion 32 is arranged in the step located inside the step. The difference in thermal expansion coefficient between the translucent portion 32 and the lens body 40 is made smaller than the difference in thermal expansion coefficient between the translucent portion 32 and the main body portion 11 . With these configurations, the lens body 40 can reduce the stress applied to the translucent portion 32 , and thus damage to the translucent portion 32 can be reduced.

Components of the light emitting device 200 will be described below.

(Substrate 10)
The base 10 has a body portion 11 and a frame portion 12 provided on the top surface of the body portion 11 .

Since the laser element 20 is mounted on the main body 11, a material with relatively high thermal conductivity is used. In the light-emitting device 200, a metal material containing copper as a main component is used as the body portion 11. As shown in FIG. In the present specification, the term "contained as a main component" means containing a material exceeding 50% of the total weight. As the body portion 11, it is preferable to use one containing copper in an amount of 99% or more of the total weight.

In the light emitting device 200, the area where the laser element 20 is arranged on the upper surface of the main body 11 is located above the area where the frame 12 is fixed. That is, the body part 11 is partially convex upward, and the laser element 20 is arranged on the upper surface of the convex part. This can reduce peeling of the laser element 20 due to warping of the main body 11 .

The frame portion 12 is fixed to the upper surface of the body portion 11 so as to surround all the laser elements 20 fixed to the body portion 11 when viewed from above. As the frame portion 12, it is preferable to use a material having a coefficient of thermal expansion close to that of the support portion 31 of the lid 30, which will be described later. Thereby, it is possible to suppress damage to the translucent portion 32 due to heat generated when the frame portion 12 and the support portion 31 are welded together. As the frame portion 12, for example, a material containing iron as a main component can be used. In the light-emitting device 200, a nickel-iron alloy is used as a material containing iron as a main component. In addition, materials containing iron as a main component include stainless steel and kovar. In the light emitting device 200, the frame portion 12 is composed of a first frame portion including a portion for fixing the lid 30 and a second frame portion provided on the outer surface of the first frame portion. However, it may be composed only of the first frame.

The outer edge of the upper surface of the frame portion 12 is square when viewed from above. As a result, the laser elements 20 can be arranged in a straight line, so that variations in the arrangement of the laser elements 20 can be reduced. The outer edge of the upper surface of the frame portion 12 may be circular. In this case, since the stress applied to the support portion 31 can be made uniform over the entire support portion 31, breakage of the translucent portion 32 can be easily reduced. Four lead pins 13 are fixed to the frame portion 12 . The number of lead pins 13 can be changed according to the number of laser elements 20 in the Y direction.

(laser element 20)
One or more laser elements 20 are arranged on the upper surface of the body portion 11 of the base 10 . It is preferable that two or more laser elements 20 are arranged on the upper surface of the body portion 11, and 14 laser elements 20 are arranged here. As the number of laser elements 20 increases, the amount of heat generated by the laser elements 20 as a whole increases, and the main body 11 is more likely to warp. Preferably, the number of laser elements 20 in the X direction is greater than the number of laser elements 20 in the Y direction. This is because the spread of the laser light in the X direction is narrower than the spread of the laser light in the Y direction, so the number of laser elements 20 that can be arranged in the main body 11 can be increased without increasing the size of the main body 11 . In addition, since there is no need to increase the size of the body portion 11, it is possible to prevent the body portion 11 from easily warping.

At least one of the two or more laser elements 20 arranged in the main body 11 preferably contains a nitride semiconductor, more preferably a GaN-based semiconductor. Since the laser element 20 including a GaN-based semiconductor easily collects dust, the effect of reducing dust collection by hermetic sealing is remarkable. In light-emitting device 200, all laser elements 20 include GaN-based semiconductors. As a GaN-based semiconductor, for example, one containing at least one of GaN, InGaN, and AlGaN can be used. The emission peak wavelength of the laser element 20 is preferably within the range of 420 nm to 570 nm, more preferably within the range of 430 nm to 550 nm.

As shown in FIGS. 3 to 5, the laser element 20 is arranged so that light is emitted in parallel with the upper surface of the main body 11. As shown in FIGS. In other words, the laser element 20 is arranged so that its light emitting end surface is perpendicular to the upper surface of the main body 11 . As a result, the main surface of the laser element 20 can be mounted in parallel with the main body 11, so that the heat generated in the laser element 20 can be easily dissipated. Each laser element 20 is fixed to each submount 70 , and the laser element 20 is mounted on the main body 11 via the submount 70 . As a result, the distance from the light emitting point on the light emitting end face of each laser element 20 to the upper surface of the main body 11 can be increased by the thickness of the submount 70, so that the light emitted from the laser element 20 can be emitted efficiently. A light reflector 90, which will be described later, can be irradiated with the light.

Submount 70 preferably has a thermal expansion coefficient between that of main body 11 and that of each laser element 20 . As a result, peeling of the laser element 20 and peeling of the submount 70 can be suppressed. When a material containing a nitride semiconductor is used as the laser element 20, the submount 70 is made of aluminum nitride or silicon carbide, for example. Each submount 70 is provided with a metal film, and each laser element 20 is fixed to each submount 70 by a conductive layer such as Au--Sn.

As shown in FIGS. 3 and 4, each laser element 20 is electrically connected to the lead pin 13 by a wire 60 (fine metal wire). Here, a submount 80 on which no laser element is arranged is arranged below the lead pin 13 . Then, the laser element 20 arranged at one end of the two or more laser elements 20 arranged in the X direction and the submount 80 are electrically connected by wires 60, and the submount 80 and the lead pins 13 are electrically connected by wires 60. properly connected. As a result, it is possible to reduce the lengthening of the wire 60 , thereby making it easier to suppress breakage of the wire 60 . A material similar to that of the submount 70 can be used for the submount 80 .

As shown in FIG. 5, one or more light reflectors 90 are arranged on the upper surface of the body portion 11 and inside the frame portion 12 . The light reflector 90 reflects the light emitted from each laser element 20 toward the transparent portion 32 . Here, the same number of light reflectors 90 as the number of laser elements 20 are fixed to the main body 11 without interposing the submount 70 therebetween. By using the light reflector 90, compared with the case where the light from each laser element 20 is directly irradiated to the light transmitting portion 32 without passing through the light reflector 90, the light from the light emitting end face of each laser element is projected onto the lens. Since the path of the light to the light incident surface of the body 40 can be lengthened, the influence of mounting misalignment between the light reflector 90 and each laser element 20 can be reduced.

As the light reflector 90, an optical element having at least one light reflecting surface is used. As an optical element, the main material is made of glass such as quartz or BK7, metal such as aluminum, or heat-resistant material such as Si, and the light reflecting surface is made of a material with high reflectance such as metal or dielectric multilayer film. can use things.

(Lid 30)
A lid 30 is fixed to the upper surface of the frame portion 12 . The lid 30 has a support portion 31 that opens inside the frame portion 12 when viewed from above, and a translucent portion 32 that closes the opening. In the following description of the lid body 30, "parallel" includes not only being completely parallel to the reference plane, but also being inclined by 10 degrees or less. In addition, "perpendicular" includes not only being completely perpendicular to the reference plane, but also being inclined by 10 degrees or less.

A material having a relatively low thermal conductivity is used for the material of the support portion 31 so as to facilitate welding with the frame portion 12 . For example, materials similar to those exemplified for the frame 12 can be used. In the light-emitting device 200 , the space in which the laser element 20 is arranged is hermetically sealed by the base 10 and the lid 30 .

As shown in FIG. 4, the support portion 31 includes a first portion 31a fixed to the upper surface of the frame portion 12, and a lens body 40 provided inside the first portion 31a at a position lower than the first portion 31a. and a third portion 31c provided inside the second portion 31b at a position lower than the second portion 31b and having the translucent portion 32 disposed thereon. As shown in FIG. 4, the first to third portions 31a to 31c preferably include regions parallel to the lower surface of the main body portion 11. As shown in FIG. Thereby, fixing to the frame part 12 and fixing of the lens body 40 and the translucent part 32 can be easily performed. Note that the second portion 31b does not have to include a flat region.

In the light emitting device 200, the support portion 31 is provided between the second portion 31b and the third portion 31c when viewed from above, at a position lower than the second portion 31b and higher than the third portion 31c. It has a fourth portion 31d. As a result, when the supporting portion 31 and the translucent portion 32 are joined using the first joining material 33, the first joining material 33 can be prevented from creeping up to the second portion 31b. becomes easier to fix. The fourth portion 31 d includes a region parallel to the bottom surface of the main body portion 11 . Note that the fourth portion 31d may be omitted. That is, the second portion 31b and the third portion 31c may be connected by a sixth portion 31f, which will be described later.

The support portion 31 can have a fifth portion 31e connecting the first portion 31a and the second portion 31b. In the light emitting device 200, the fifth portion 31e is bent inwardly from the frame portion 12 so as to protrude downward at a position lower than the second portion 31b. In other words, the fifth portion 31e extends from the first portion 31a to a position lower than the second portion 31b so as not to come into contact with the frame portion 12, and then bends inward and upward to be connected to the second portion 31b. is provided as follows. As a result, the downwardly extending region of the fifth portion 31e can be elastically deformed to facilitate stress absorption. Furthermore, since physical strength can be ensured in the upward bending region, breakage of the lens body 40 and the translucent portion 32 can be reduced. Further, by providing the curved region in the fifth portion 31e, the excess second bonding material 50 can be retained. When the second bonding material and the first bonding material come into contact with each other, light from the laser element hits the second bonding material, possibly degrading the second bonding material. By arranging the second bonding material 50 to the outside, it is possible to suppress the second bonding material 50 from entering the inside and coming into contact with the first bonding material 33 . The length from the top to the bottom of the fifth portion 31e can be, for example, within the range of 1.5 mm or more and 4 mm or less. The lowest portion of the fifth portion 31e is preferably lower than the lowest portion of the third portion 31c. As a result, the length from the top to the bottom of the fifth portion 31e can be increased, so stress can be easily absorbed.

The support portion 31 has a sixth portion 31f connecting the second portion 31b and the fourth portion 31d. The sixth portion 31f includes a slanted region extending from the inside to the outside. At this time, it is preferable that the surface is inclined within a range of 30 degrees or less from a plane perpendicular to the lower surface of the main body portion 11 . As a result, the sixth portion 31f that connects the fourth portion 31d and the second portion 31b can be formed as a steep region to some extent. .

The support portion 31 has a seventh portion 31g connecting the third portion 31c and the fourth portion 31d. This makes it easier to align the translucent portion 32 . It is preferable that the seventh portion 31g includes a region that is inclined in a range of 15 degrees or less from a plane perpendicular to the lower surface of the main body. This makes it easier to reduce the creeping up of the first bonding material 33 to the fourth portion 31d.

Preferably, the support portion 31 is relatively thin and has a constant thickness. That is, it is preferable that the supporting portion 31 is a thin plate. As a result, the support portion 31 can be manufactured by press working, so that manufacturing costs can be reduced. For example, the thickness of the supporting portion 31 as a whole is preferably in the range of 0.03 mm or more and 0.2 mm or less, and more preferably in the range of 0.05 mm or more and 1.5 mm or less. In the light-emitting device 200, a region of the supporting portion 31 excluding at least the region fixed to the frame portion 12 has a constant thickness. That is, the second portion 31b to the seventh portion 31g have the same thickness. Note that when the first portion 31a is fixed to the frame portion 12 by welding, that portion may become slightly thin. The thickness here means the length in the vertical direction for the first to fourth portions 31a to 31d, and the length in the horizontal direction for the fifth to seventh portions 31e to 31g. In addition, the term "same thickness" as used herein includes a difference in thickness of ±10% or less.

The translucent portion 32 is fixed to the third portion 31c so as to block the opening of the support portion 31. As shown in FIG. Here, the translucent portion 32 is fixed to the upper surface of the third portion 31c, and the outer edge of the translucent portion 32 is positioned outside the outer edge of the opening when viewed from above.

In the light-emitting device 200 , glass is used as the material of the translucent portion 32 . In addition, for example, sapphire can be used. The thickness (vertical length) of the translucent portion 32 is preferably in the range of 0.5 mm or more and 1 mm or less. The strength of the translucent portion 32 can be ensured by making it equal to or greater than the aforementioned lower limit, and the distance from the light reflector 90 to the lens body 40 can be reduced by making it equal to or less than the aforementioned upper limit.

The translucent portion 32 is fixed to the support portion 31 with a first bonding material 33 . As the first bonding material 33, a material having a coefficient of thermal expansion relatively close to that of the translucent portion 32 and the support portion 31 can be used. The first bonding material 33 is preferably an inorganic material in order to reduce dust collection on the laser element 20 . Low-melting-point glass, for example, can be used as the first bonding material 33 .

(Lens body 40)
The lens body 40 is spaced upward from the translucent portion 32 and controls the light distribution of the light from the laser element 20 . The lens body 40 is fixed inside the inner edge of the first portion 31 a of the support portion 31 . This makes it easier to fix other members to the upper surface of the first portion 31a. For example, as shown in FIGS. 6 and 7, in order to reduce dust collection on the lens body 40, a tubular light guide member 100 is fixed to the upper surface of the first portion 31a, and the end portion of the light guide member 100 is can be covered with lid 110 . That is, one end of the light guide member 100 and the first portion 31a are fixed, and the other end of the light guide member 100 and the lid 110 are fixed. Accordingly, it is possible to reduce the adhesion of relatively large dust or the like to the lens body 40 . The space formed by the support portion 31, the light guide member 100, and the lid 110 is preferably an airtightly sealed space. As a result, it is possible to prevent relatively small dust from entering the space where the lens body 40 is arranged, so that the reliability of the light emitting device 200 can be improved.

In the light-emitting device 200, a cylindrical light-guiding member 100 having a truncated square pyramid with a hollow inside is used. As the cylindrical light guide member 100, a square prism having a hollow inside, a cylindrical shape having a hollow inside, or the like may be used. In FIGS. 6 and 7, the light guide member 100 used has a width that narrows from one end to the other end of the light guide member 100. One that is provided or one that widens from one end to the other may be used. As the lid 110, a translucent material such as glass or sapphire can be used. A member such as a wavelength conversion member or a lens may be arranged in the space formed by the support portion 31 , the light guide member 100 and the lid 110 .

In the light emitting device 200, a collimating lens is used as the lens body 40 so that the light passing through the lens portion 41 provided in the lens body 40 approaches parallel light. Note that the collimator lens referred to here also includes a lens unit 41 that completely parallelizes light.

It is preferable that the difference in thermal expansion coefficient between the lens body 40 and the translucent portion 32 is as small as possible. This makes it easier to reduce damage to the translucent portion 32 . The difference in thermal expansion coefficient between the lens body 40 and the translucent portion 32 can be, for example, 5×10 ⁻⁶ /° C. or less, preferably 2×10 ⁻⁶ /° C. or less. As the lens body 40, glass such as "B270" and "BK7" (borosilicate glass) manufactured by SCHOTT can be used.

As shown in FIG. 2 , the lens body 40 has a plurality of lens portions 41 and a non-lens portion 42 surrounding the plurality of lens portions 41 when viewed from above. Here, the plurality of lens portions 41 and the non-lens portions 42 are integrally formed of the same material. Then, as shown in FIG. 4 , the non-lens portion 42 and the second portion 31 b are connected by the second bonding material 50 . This makes it possible to fix the lens body 40 to the support portion 31 while reducing the incidence of the laser light hitting the second bonding material 50 . When viewed from above, the second portion 31b is provided along the inner edge of the frame portion 12, and the lens body 40 is fixed in a frame shape at the second portion 31b. That is, the lens body 40 is fixed to the support portion 31 inside the frame portion 12 in any vertical cross section of the light emitting device 200 . As a result, even if the frame portion 12 is pulled so as to expand outward, the lens body 40 can suppress the expansion, so that damage to the translucent portion 32 can be reduced. The thermal expansion coefficient of the entire lens body 40 is close to the thermal expansion coefficient of the translucent portion 32, and the lens portion 41 and the non-lens portion 42 are made of different materials. good too.

The lens portion 41 is provided continuously with adjacent lens portions in the direction in which the spread of the laser light is small. That is, the lens portions 41 are provided continuously in the X direction. As a result, the lens body 40 can be made smaller, and the light emitting device 200 as a whole can be made smaller.

The second bonding material 50 is preferably made of a material having a Young's modulus smaller than that of the first bonding material 33 . Since the second bonding material 50 is provided in a region closer to the frame portion 12 than the first bonding material 33, stress is likely to be applied thereto. 40 breakage can be reduced. As the second bonding material 50, it is preferable to use a resin, and it is more preferable to use an ultraviolet curable resin. By using an ultraviolet curable resin, it is not necessary to adjust the lens body 40 while considering the time until the second bonding material 50 is cured, so the position of the lens body 40 can be accurately adjusted. In FIG. 4, the second bonding material 50 is in contact with the fifth portion 31e that relieves the stress in the support portion 31, but it may be provided only in the second portion 31b. In this way, even when in contact with the fifth portion 31e, since a material with a small Young's modulus is used, it is considered that the effect of stress relaxation in the fifth portion 31e can be obtained.

The light emitting device 200 described in the embodiments can be used for projectors and the like.

DESCRIPTION OF SYMBOLS 10... Base|substrate 11... Main-body part 12... Frame part 13... Lead pin 20... Laser element 30... Cover body 31... Support part 31a... 1st site|part 31b... 2nd site|part 31c... 3rd site|part 31d... 4th site|part 31e... 5th site Part 31f Sixth part 31g Seventh part 32 Translucent part 33 First bonding material 40 Lens body 41 Lens part 42 Non-lens part 50 Second bonding material 60 Wire 70, 80 Submount 90... Light reflector 100... Light guide member 110... Lid 200... Light emitting device

Claims (7)

a base body having a main body portion and a frame portion provided on the upper surface of the main body portion and having an upper surface forming a first opening;
one or more laser elements provided on the upper surface of the main body inside the frame and below the upper surface of the frame;
A lid having a support portion fixed to the upper surface of the frame portion and provided with a second opening inside the first opening of the frame portion, and a light-transmitting portion provided to close the second opening. body and
and a lens body disposed on the support portion inside the first opening of the frame portion and above the translucent portion when viewed from above . The support part is
a first portion fixed to the upper surface of the frame;
a second portion provided at a position lower than the first portion inside the first portion, where the lens body is arranged;
2. The light-emitting device according to claim 1, further comprising a third portion provided inside said second portion and at a position lower than said second portion, where said translucent portion is arranged. 3. The light emitting device according to claim 2, wherein said second portion and said third portion of said support portion have the same thickness. The lens body has a lens portion,
The light emitting device according to claim 1, wherein the apex of the lens portion of the lens body is located higher than the upper surface of the frame portion. The light-emitting device according to claim 1, wherein the thickness of the lens body is greater than the thickness of the translucent portion. The lens body has a lens portion and a non-lens portion surrounding the lens portion,
2. The light-emitting device according to claim 1, wherein said non-lens portion of said lens body has a thickness greater than that of said translucent portion. 7. The light-emitting device according to claim 5, wherein the thickness of said translucent portion is 1 mm or less.

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