JP2006352047A - Optical semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical semiconductor device capable of emitting a high-intensity light toward immediately above thereof, and having high directivity. <P>SOLUTION: The semiconductor device is provided with a semiconductor light-emitting device arranged on the upper surface of a substrate; a case to be arranged on the upper surface of the substrate so as to surround the semiconductor light-emitting device from the lower part of the substrate to an opening; and a lens formed at least up to such a predetermined height as to cover the semiconductor light-emitting device from the lower part of the substrate in a space formed by the case, and arranged on the upper part of a sealing section in a space formed by the sealing section having the upper surface made of a flat light transmitting material and the case. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical semiconductor device including a semiconductor light emitting element. In particular, the present invention relates to an optical semiconductor device used as a light source for display or illumination.

  A conventional optical semiconductor device including a light emitting element includes a light emitting element in a concave casing, and fills the concave portion with a light-transmitting resin so as to cover the light emitting element (see, for example, Patent Document 1). ).

  A configuration example of a conventional optical semiconductor device is shown in FIG. In FIG. 1, reference numeral 81 denotes a light emitting element, 82 denotes a sealing portion that covers the light emitting element 81, 83 denotes a concave casing, and 84 denotes a substrate on which the light emitting element 81 and the like are mounted.

  After the housing 83 is arranged on the substrate 84, the light emitting element 81 is mounted, and the electrode of the light emitting element 81 and the wiring pattern on the substrate 84 are connected by leads.

JP 2002-261333 A

  The sealing part 82 uses an epoxy resin or a silicone resin as a material. When the housing 83 is initially filled with such a resin, the upper surface of the sealing portion 82 is flat. However, as this is dried and cured, the material shrinks, and the upper surface of the sealing portion 82 is Indentation occurs as shown in FIG.

  In such a case, the light emitted from the light emitting element 81 is diffused on the upper surface of the sealing portion 82, and the intensity of the light emitted directly above the optical semiconductor device is weakened. The optical semiconductor device is for supplying light to a display unit such as a display provided directly above the light emitting element 81. Therefore, it is preferable that the intensity of light emitted directly above is high.

  In view of such a problem, an object of the present invention is to provide an optical semiconductor device having high directivity that can emit light having a high intensity directly above the optical semiconductor device.

  In order to achieve the above object, an optical semiconductor device according to the present invention has a casing disposed around a semiconductor light emitting element, a sealing portion is formed in a space formed in the casing, and the top of the sealing portion is formed. Is equipped with a lens.

  Specifically, an optical semiconductor device according to the present invention includes a semiconductor light emitting element disposed on an upper surface of the substrate, and an upper surface of the substrate so as to surround the periphery of the semiconductor light emitting element from the lower part on the substrate side toward the opening. And a space formed by the casing, and is formed from a lower part on the substrate side to a predetermined height that covers at least the semiconductor light emitting element, and is made of a translucent material having a flat upper surface. A sealing portion and a lens disposed on an upper surface of the sealing portion in a space formed by the casing are provided.

  A semiconductor light emitting element is provided in a concave portion that is a space formed by a housing, a sealing part is formed so as to cover the semiconductor light emitting element, and a lens is disposed on the upper surface of the sealing part, so that the sealing part is cured. However, when a dent occurs on the upper surface, the light emitted in the direction of diffusing from directly above the sealing portion can be collected and emitted upward.

  In the optical semiconductor device according to the present invention, the lens may have a cylindrical shape, and a part of a circumference of the cylindrical shape may be in contact with the upper surface of the sealing portion. By setting it as a cylindrical lens, it can arrange | position on a sealing part, without being influenced by the flatness of a sealing part. It is suitable when the sealing portion is cured and a dent is generated on the upper surface of the sealing portion.

  Furthermore, in the optical semiconductor device according to the present invention, the lens has a semi-cylindrical shape, and the axial plane surface side of the semi-cylindrical shape is in contact with the upper surface of the sealing portion. The semi-cylindrical shape is a shape formed by extending a plane formed by an arc and a string connecting both ends of the arc into a columnar shape in a direction perpendicular to the plane. The plane side in the axial direction is the plane shape side of the plane formed in the direction perpendicular to the plane formed by the arc and the string connecting the ends of the arc. By using a semi-cylindrical lens, the flat surface of the lens can be brought into contact with the upper surface of the sealing portion, and light that diffuses in a direction other than the upward direction from the upper surface of the sealing portion can be efficiently collected. it can.

  In the optical semiconductor device according to the present invention, the uppermost part of the lens arranged in the space formed by the casing and the plane forming the opening in the casing have substantially the same height. It is preferable. When the top of the lens and the upper plane of the housing are substantially the same height, there is no gap between the optical semiconductor device and the display when used in combination with a display using the optical semiconductor device. The light emitted from the device can be efficiently emitted to the display.

  In addition, the optical semiconductor device according to the present invention includes that the lens and the upper surface of the sealing portion are bonded with a transparent adhesive. By using a transparent adhesive, it is possible to reduce light loss between the sealing portion and the lens or light loss due to refractive index mismatch between the sealing portion and air or between the lens and air.

  According to the present invention, light with high intensity can be emitted directly above an optical semiconductor device, and an optical semiconductor device with high directivity can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to embodiment shown below.

  The optical semiconductor device according to this embodiment is disposed on the upper surface of the substrate so as to surround the semiconductor light emitting element disposed on the upper surface of the substrate and the semiconductor light emitting element from the lower portion on the substrate side toward the opening. A sealing portion made of a light-transmitting material having a flat upper surface formed from a lower portion on the substrate side to a predetermined height that covers at least the semiconductor light emitting element in a space formed by the housing; And a lens disposed on the upper surface of the sealing portion in the space formed by the housing.

  The structure of the optical semiconductor device of the present invention will be described with reference to FIGS. FIG. 2 is a perspective view of the optical semiconductor device 100 according to the present embodiment. 3 is a cross-sectional view of the optical semiconductor device 100 taken along line A-A ′ in the perspective view of FIG. 2.

  2 and 3, the optical semiconductor device 100 includes a semiconductor light emitting element 1, a substrate 2, a housing 3, a sealing unit 4, and a lens 5. The sealing unit 4 and the lens 5 are accommodated in a space 6 formed by the housing 3. 2 and 3, the lens 5 has a cylindrical shape, but in the present embodiment, it may be a semi-cylindrical lens described later, or may have another shape. The upper surface 7 of the sealing portion 4 and the lens 5 are bonded by an adhesive 8.

  The semiconductor light emitting element 1 is connected to a lead frame 11 provided on the surface of the substrate 2 through bonding wires 12. The lead frame 11 is connected to, for example, a through hole 13 that penetrates the substrate 2 and whose inner wall is covered with metal.

  The substrate 2 is made of an insulator. For example, ceramic or glass epoxy.

The semiconductor light emitting element 1 is disposed on the upper surface of the substrate 2 and emits light at a predetermined wavelength by a current supplied by the bonding wire 12. The semiconductor light emitting device 1 is a nitride made of a group III nitride compound represented by Al _x Ga _y In _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). An example is a physical semiconductor light emitting device. In addition, a compound having a composition such as ZnCdSe, ZnTeSe, GaP, AlGaInP, or AlGaAs may be used. When the semiconductor light emitting device 1 includes a semiconductor layer formed on, for example, a sapphire substrate, the semiconductor light emitting device 1 may be directly mounted on the substrate 2 or may be mounted on the lead frame 11. When the semiconductor light emitting device 1 includes a semiconductor layer formed on a semiconductor substrate, the semiconductor light emitting device 1 is preferably mounted on the lead frame 11 in order to reduce the bonding wires 12. Even when the semiconductor light emitting device 1 includes a semiconductor layer formed on an insulator, the semiconductor light emitting device 1 is preferably mounted on the lead frame 11 in order to improve heat dissipation.

  A housing 3 is disposed on the upper surface of the substrate 2 so as to surround the semiconductor light emitting element 1. The housing 3 has an opening 9 directed from the substrate surface to the upper part. The housing 3 reflects light emitted from the semiconductor light emitting element 1 on the inner side surface of the housing 3 toward the opening 9. The inner side surface of the housing 3 may be formed at a right angle to the upper surface of the substrate 2, and may be gradually tapered toward the opening 9 as a tapered shape. Further, in the case of a taper shape, it may be linear, wavy or stepped. It suffices that at least a part of the inner side surface of the housing 3 has a surface that reflects the light from the semiconductor light emitting element 1 in the upward direction of the substrate 2.

  In FIG. 2, the opening is a quadrangle parallel to the substrate 2, but it may be a polygon, a circle, or an ellipse. Moreover, the housing | casing 3 is good also as a single material and a single structure, and may be comprised with a some material or may combine a some structure.

  The surface in contact with the sealing portion 4 of the housing 3 is preferably roughened. When the casing 3 is roughened, the adhesion between the casing 3 and the sealing portion 4 is improved and peeling can be prevented. The total reflection that occurs at the interface is stably generated. When total reflection occurs stably, the optical semiconductor device 100 can obtain stable emission efficiency.

  The material of the housing 3 may be a light transmissive material. For example, an epoxy resin can be exemplified. The casing 3 preferably contains reflective particles. As the reflective particles, for example, a metal foil or metal powder such as silver or aluminum may be mixed. White liquid crystal polymer may be used as the housing material. When the casing 3 includes such reflective particles, light incident on the casing 3 from the sealing portion 4 is absorbed in the casing 3, and thus biased to the emission pattern from the optical semiconductor device 100. There is no constant shape.

  The sealing portion 4 is formed in a space 6 formed by the housing 3 from a lower portion on the substrate 2 side to a predetermined height that covers at least the semiconductor light emitting element 1. The sealing unit 4 may be formed so as to contact the inner side surface of the housing 3, and an air layer may be provided between the sealing unit 4 and the housing 3. When the sealing portion 4 and the inner side wall of the housing 3 are in contact with each other, peeling can be prevented, and thus total reflection that occurs at the interface between the sealing portion 4 and the housing 3 is stably generated. . When total reflection occurs stably, the optical semiconductor device 100 can obtain stable emission efficiency.

  The material of the sealing part 4 is a translucent material. In order to efficiently emit light from the semiconductor light emitting element 1, the refractive index of the material of the sealing portion 4 is preferably close to that of the semiconductor layer of the semiconductor light emitting element 1. Examples of materials that have a relatively high refractive index and can be easily processed include glass, silicone resin, epoxy resin, and PMMA (polymethyl methacrylate).

  The sealing part 4 may not be a single material or a single structure. A plurality of materials may be used, or a plurality of structures may be combined.

  The refractive index of the material of the sealing part 4 is set larger than the refractive index of the material of the housing 3. When light from the semiconductor light emitting element 1 enters the housing 3 from the sealing portion 4, total reflection generated at the interface between the sealing portion 4 and the housing 3 can be used. The emission efficiency can be increased.

  Further, the phosphor 14 may be added to the sealing portion 4. The phosphor 14 has an energy gap smaller than the wavelength of the light emitted from the semiconductor light emitting device 1, and thus can be converted into light having a long wavelength in response to the light emitted from the semiconductor light emitting device 1. The phosphor 14 may be a YAG (Yttrium Aluminum Garnet) phosphor, or a TAG phosphor or an RGB phosphor. For example, the light from the semiconductor light emitting element 1 that emits blue light may be converted into a complementary color of blue and additively mixed to produce white light, or may be emitted with various spectra by additive color mixing. .

  The lens in the present embodiment is preferably provided as a cylindrical lens 5 as shown in FIG. 3 so that a part of the circumference of the cylindrical shape is in contact with the upper surface 7 of the sealing portion 4. By using a cylindrical lens, the flatness of the sealing portion 4 is not affected, and the lens can be disposed on the upper surface 7 of the sealing portion 4 and collects light diffused on the upper surface 7 of the sealing portion 4. can do. It is suitable when the sealing part 4 is hardened in the manufacturing process and a dent is generated on the upper surface 7 of the sealing part 4.

  Further, the lens in the present embodiment is preferably provided as a semi-cylindrical lens 20 as shown in FIG. 4 so that the semi-cylindrical axial plane side is in contact with the upper surface 7 of the sealing portion 4. The semi-cylindrical shape is a shape formed by extending a plane formed by an arc and a string (string portion 21) connecting both ends of the arc into a columnar shape in a direction perpendicular to the plane. The plane formed by the arc and the chord portion 21 may be a semicircular shape or a plane formed by using the arc as a parabola. The plane side in the axial direction is the plane shape side of the plane formed in the direction perpendicular to the plane formed by the arc and the chord portion 21 connecting both ends of the arc. By using a semi-cylindrical lens, the upper surface 7 of the sealing portion 4 can be brought into contact with the flat surface of the lens, and light diffused from the upper surface 7 of the sealing portion 4 in a direction other than the upward direction can be efficiently collected. can do. Hereinafter, the optical semiconductor device 100 according to the present embodiment will be described with the form using the lens 5 described with reference to FIG.

  Further, in the lens 5, it is preferable that the uppermost portion 22 of the lens 5 disposed in the space 6 formed by the housing 3 and the plane that forms the opening 9 of the housing 3 have substantially the same height. . When the top surface 22 and the plane of the opening 9 are substantially the same height, when used in combination with a display (not shown) using the optical semiconductor device 100, the optical semiconductor device 100 and the display (not shown) are between. There is no gap, and the light emitted from the optical semiconductor device 100 can be efficiently emitted to a display (not shown).

  The material of the lens can be exemplified by glass, silicone resin, epoxy resin, PMMA (polymethyl methacrylate) and the like as materials having a relatively high refractive index and easy processing.

  It is preferable that the lens 5 and the upper surface 7 of the sealing portion 4 are bonded with a transparent adhesive 8. By using the transparent adhesive 8, it is possible to reduce light loss between the sealing portion 4 and the lens 5 or light loss due to refractive index mismatch between the sealing portion 4 and air or between the lens 5 and air. . Examples of the material of the adhesive 8 include an epoxy adhesive.

  A through hole 13 is provided in the substrate 2, and a lead frame 11 on the upper surface of the substrate 2 and a lead frame (not shown) on the lower surface of the substrate 2 are connected by metal wiring covering the inner wall of the through hole 13. Such a lead frame 11 enables flip chip connection on a circuit board or a flexible wiring board.

  Each of the components of the optical semiconductor device 100 (sealing part 4, adhesive, lens (lens 5 or lens 20)) and the refractive index of air may be any of the following. Here, the air refers to the air surrounding the optical semiconductor device 100. (1) Sealing part 4> Adhesive> Lens> Air, (2) Sealing part 4 = Adhesive> Lens> Air, (3) Sealing part 4> Adhesive = Lens> Air, (4) Sealing Part 4 = Adhesive = Lens> Air, (5) Sealing part 4 = Adhesive <Lens> Air, (6) Sealing part 4> Adhesive <Lens> Air.

  (1) to (6) in FIG. 5 show six views when the lens 5 is used in the optical semiconductor device 100 of the present embodiment. 5 (1) is a front view, FIG. 5 (2) is a rear view, FIG. 5 (3) is a right side view, FIG. 5 (4) is a left side view, FIG. 5 (5) is a plan view, and FIG. 6) is a bottom view.

  In FIGS. 5A and 5B, the upper quadrangular shape indicates the housing 3, and the lower quadrangular shape indicates the substrate 2. 5 (3) and 5 (4), the upper quadrangular shape indicates the housing 3, and the lower side indicates a state in which the through hole 13 is provided on the surface of the substrate 2. FIG. In FIG. 5 (5), a cylindrical lens 5 is provided in the inner square shape (see the cross-sectional view of FIG. 3). In FIG. 5 (6), the semicircle at the center of the left and right sides indicates the through hole 13. 5 (3) and 5 (4), the cylindrical lens 5 provided inside is indicated by a dotted line.

  6 (1) to (6) are hexahedral views when the lens 20 is used in the optical semiconductor device 100 of the present embodiment. 6 (1) is a front view, FIG. 6 (2) is a rear view, FIG. 6 (3) is a right side view, FIG. 6 (4) is a left side view, FIG. 6 (5) is a plan view, and FIG. 6) is a bottom view.

  6 (1) and 6 (2), the upper quadrangular shape indicates the casing 3, and the lower quadrangular shape indicates the substrate 2. FIG. 6 (3) and 6 (4), the upper quadrangular shape indicates the housing 3, and the lower side indicates a state in which the through hole 13 is provided on the surface of the substrate 2. FIG. In FIG. 6 (5), a semi-cylindrical lens 20 is provided in the inner square shape (see the cross-sectional view of FIG. 4). In FIG. 6 (6), the semicircle at the center of the left and right sides indicates the through hole 13. 6 (3) and 6 (4), the semicylindrical lens 20 provided inside is indicated by a dotted line.

  A method for manufacturing an optical semiconductor device including the cylindrical lens of the present invention will be described. 7A to 7D are views for explaining a method of manufacturing an optical semiconductor device. 7 (1) to 7 (4), the same reference numerals as those in FIG. 2 or 3 represent the same meaning.

  First, a through hole 13 that penetrates the substrate 2 on which a plurality of semiconductor light emitting elements 1 can be mounted is formed, and the inner wall of the through hole 13 is plated with metal to connect the upper surface and the lower surface of the substrate 2. Is formed (FIG. 7 (1)). Lead frames 11 are formed in a predetermined pattern on the upper and lower surfaces of the substrate 2 (FIG. 7A). Either the wiring on the inner wall of the through hole 13 or the lead frame 11 may be formed first.

  The semiconductor light emitting element 1 is mounted on the upper surface of the substrate 2, and the electrode of each semiconductor light emitting element 1 and the lead frame 11 are connected by bonding wires 12.

  Next, the casing 3 having a predetermined shape is mounted on the substrate 2 (FIG. 7 (2)). The casing 3 may be one obtained by curing a resin with a mold, or may be one obtained by cutting the cured resin. The inner side surface of the housing 3 may be roughened by, for example, blasting in order to improve the adhesion with the sealing portion 4.

  The space 6 formed by the housing 3 is filled with, for example, PMMA, which is a material that becomes the sealing portion 4. (FIG. 7 (3)). The sealing portion 4 is filled from the upper surface of the substrate 2 to a predetermined height that covers at least the semiconductor light emitting element 1. This height should just leave the height required in order to mount a lens among the spaces 6 formed by the housing 3. After filling the material of the sealing part 4, the sealing part 4 is cured. The curing method may be thermal curing or ultraviolet curing.

  After the sealing part 4 is cured, it is preferable to perform a surface treatment so that the upper surface 7 of the sealing part 4 becomes flat. This is because the lens 5 is mounted on the upper surface 7 of the sealing portion 4.

  After curing and surface treatment of the sealing part 4, an adhesive 8 is applied to the upper surface 7 of the sealing part 4. Thereafter, the lens 5 is disposed on the upper surface 7 of the sealing portion 4 to which the adhesive 8 is applied. At this time, it is preferable to dispose the gap between the adhesive 8 and the lens 5.

  Each optical semiconductor device 100 is cut out along the cutting line (FIG. 7 (4)). Cutting may be thermal cutting with a laser or mechanical cutting with dicing. The housing 3 may be cut when the substrate 2 is cut out, or the housing 3 separated in FIG. 7B may be mounted on the substrate 2.

  By such a manufacturing method, an optical semiconductor device capable of emitting strong light just above the optical semiconductor device can be mass-produced.

  Next, mounting of the optical semiconductor device 100 will be described. The optical semiconductor device 100 may be a top view in which the substrate 2 is mounted so as to be in contact with the surface of the flexible cable or the mounting substrate and emitted in the normal direction of the flexible cable or the mounting substrate. Alternatively, a side view may be employed in which the substrate 2 and the housing 3 of the optical semiconductor device 100 are mounted so as to face the surface of the flexible cable or the mounting substrate, and are emitted in the surface direction of the flexible cable or the mounting substrate.

  FIG. 8 shows the implementation of the side view method. In FIG. 8, the optical semiconductor device 100 is mounted such that the substrate 2 and the housing 3 face the upper surface of the flexible cable 31. The optical semiconductor device 100 is connected to the flexible cable wiring portion 32 on the flexible cable 31 with solder 33 via a lead frame (not shown), and current is supplied to the semiconductor light emitting element (not shown). Light emitted from a semiconductor light emitting element (not shown) is collected by the lens 5 and emitted almost parallel to the surface of the flexible cable 31. The same applies to a mounting board instead of the flexible cable 31.

  The optical semiconductor device of the present invention can be used as a light source mounted on lighting, communication, sensors, display devices, and the like.

It is a figure explaining the structural example of the conventional optical semiconductor device. 1 is a perspective view of an optical semiconductor device according to an embodiment of the present invention. In the perspective view of FIG. 2, it is sectional drawing in a surface perpendicular | vertical to a board | substrate including A-A 'line. It is sectional drawing in a surface perpendicular | vertical to a board | substrate at the time of mounting the semicylindrical lens 20 in an optical semiconductor device. FIG. 6 is a six-sided view illustrating an external shape of an optical semiconductor device on which a lens 5 is mounted. FIG. 6 is a six-sided view showing an external shape of an optical semiconductor device on which a lens 20 is mounted. It is a figure explaining the manufacturing method of an optical semiconductor device. It is a figure explaining mounting of an optical semiconductor device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, Semiconductor light-emitting device 2, Board | substrate 3, Case 4, Sealing part 5, Lens 6, Space 7 formed by the case, Upper surface 8 of sealing part, Adhesive 9, Opening part 11, Lead frame 12, Bonding wire 13, through hole 14, phosphor 20, lens 21, string portion 22, uppermost portion 31, flexible cable 32, flexible cable wiring portion 33, solder 81, light emitting element 82, sealing portion 83, housing 84, substrate 100, optical semiconductor device

Claims (5)

A semiconductor light emitting device disposed on an upper surface of the substrate;
A housing disposed on the upper surface of the substrate so as to surround the periphery of the semiconductor light emitting element from the lower part on the substrate side toward the opening;
Of the space formed by the housing, a sealing portion made of a light-transmitting material having a flat upper surface formed from the lower part on the substrate side to a predetermined height that covers at least the semiconductor light emitting element;
An optical semiconductor device comprising: a lens disposed on an upper surface of the sealing portion in a space formed by the housing.   The optical semiconductor device according to claim 1, wherein the lens has a cylindrical shape, and a part of a circumference of the cylindrical shape is in contact with an upper surface of the sealing portion.   2. The optical semiconductor device according to claim 1, wherein the lens has a semi-cylindrical shape, and an axial plane surface side of the semi-cylindrical shape is in contact with an upper surface of the sealing portion.   The uppermost part of the lens arranged in a space formed by the casing and a plane forming the opening in the casing are substantially the same height. 2. The optical semiconductor device according to 2 or 3. The optical semiconductor device according to claim 1, wherein the lens and the upper surface of the sealing portion are bonded with a transparent adhesive.

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