JP5724757B2 - Semiconductor light emitting device - Google Patents

Description

  The present invention relates to a semiconductor light emitting device using a semiconductor light emitting element such as an LED element.

Communication LED (Light Emitting Diode) devices that use radiated light incident on an optical fiber or an optical waveguide have a low proportion of light that is not introduced into the optical fiber or optical waveguide, and the amount of light introduced into the optical fiber or optical waveguide is low. What has a low insertion loss is required.
As a communication LED device, for example, there is a device in which a green light emitting LED element is mounted on a flat lead frame and a lens is provided on the front surface of the package to collect light and increase the coupling efficiency.
However, since the emitted light from the LED element spreads in all directions, there is light that does not even enter the lens. For this reason, the ratio (coupling loss) of the light which does not enter into an optical fiber or an optical waveguide among the emitted light of an LED element is large. In addition, the low directivity causes a large insertion loss of light introduced into an optical fiber or an optical waveguide. A general display LED has low directivity and has the same problem.

  Therefore, as a composite coupling mirror that reduces the coupling loss, Patent Document 1 discloses that a parabola and a curve obtained by rotating the parabola around the focal point are rotated about the axis of symmetry of the parabola as a rotation axis. The surface obtained is a rotating mirror surface.

JP 2003-262663 A

  However, in the composite type coupling mirror of Patent Document 1, it is difficult to guide the radiated light emitted from the side surface of the LED element to the opening, so that it is difficult to sufficiently reduce the coupling loss to the optical fiber or the optical waveguide. Conceivable.

  Accordingly, an object of the present invention is to provide a semiconductor light emitting device in which a coupling loss to an optical fiber, an optical waveguide, or the like is reduced.

In order to solve the above-described problems, a semiconductor light emitting device of the present invention includes a semiconductor light emitting element, a circular mounting surface on which the semiconductor light emitting element is mounted, and the semiconductor standing up from an outer edge of the mounting surface. surrounds the lateral side of the light emitting element, wherein possess a reflecting surface for reflecting the emitted light of the semiconductor light emitting element, a semiconductor light emitting device for communication incident radiation into an optical fiber or an optical waveguide, the reflection surface The plane curve on a plane passing through the center of the mounting surface and orthogonal to the mounting surface is rotated about a line passing through the center of the mounting surface as a rotation axis. The plane curve is a first curve extending from a lower end point on the outer edge to an intermediate point above the lower end point, and from the intermediate point above the intermediate point, and the reflective surface A second curve extending to the upper end point that is the upper end of the Of the crossing angles between the perpendicular of the axis of rotation and the first straight line extending from the lower end point to the middle point, the angle θ1 of the minor angle is 56.61 ° ≦ θ1 ≦ 74.63 °, and the first straight line to the first straight line The length I1 of the longest first vertical line of the first straight line extending to the curve (where I1 takes a negative value when the first vertical line extends above the first straight line, and the first vertical line is the first vertical line) A value obtained by dividing the first straight line by a length S1 is −0.011 ≦ I1 / S1 ≦ 0.110, and the vertical axis of the rotating shaft; Of the intersecting angles with the second straight line extending from the intermediate point to the upper end point, the minor angle θ2 is 63.74 ° ≦ θ2 ≦ 66.30 °, and extends from the second straight line to the second curve. , The length I2 of the longest second perpendicular to the second straight line (where I2 is the second perpendicular Is taken to be a negative value if it extends above the second straight line and takes a positive value if the second perpendicular extends below the second straight line) by the length S2 of the second straight line. The value obtained is 0.041 ≦ I2 / S2 ≦ 0.078.

Although it does not specifically limit as a semiconductor light emitting element, A light emitting diode (LED) element, a laser diode element, etc. can be illustrated.
The semiconductor light emitting device can be exemplified by a plate shape that is substantially square in plan view and rectangular in side view.
Although the magnitude | size of a semiconductor light-emitting device is not specifically limited, It is preferable that thickness is 0.01-0.3 mm. If the thickness is less than 0.01 mm, the strength of the semiconductor light emitting device is low and it is difficult to handle. On the other hand, if it exceeds 0.3 mm, the semiconductor light emitting device itself becomes too large.

  The minimum distance from the semiconductor light emitting element to the lower end point of the plane curve is not particularly limited, but is preferably 0.01 to 0.05 mm. If the minimum distance is less than 0.01 mm, it is difficult to set the semiconductor light emitting element on the mounting surface. On the other hand, if it exceeds 0.05 mm, the coupling loss increases. More preferably, it is 0.02-0.04 mm.

  The height from the placement surface to the midpoint of the plane curve is not particularly limited, but is preferably 0.7 to 1.25 times the height from the placement surface to the upper end of the semiconductor light emitting element. If it is less than 0.7 times, the emitted light of the semiconductor light emitting device that is not reflected by the rotation surface of the first curved portion of the plane curve (mainly the emitted light from the side surface of the semiconductor light emitting device) increases, and the directivity decreases. On the other hand, if it exceeds 1.25 times, the second curve becomes shorter, so the rotation surface of the second curve portion of the plane curve becomes smaller and the directivity becomes lower.

  The height from the mounting surface to the upper end point of the plane curve is not particularly limited, but when forming the mounting surface and the reflecting surface by pressing a lead frame used in a semiconductor light emitting device, 0.5 to 1 mm. It is preferable that If it is less than 0.5 mm, directivity is difficult to obtain. On the other hand, if it exceeds 1 mm, the mounting surface and the reflecting surface are likely to be deformed.

Applications of the semiconductor light-emitting device, as described above, a communication semiconductor light emitting device such as a communication LED light-emitting device incident radiation into an optical fiber or an optical waveguide.

  ADVANTAGE OF THE INVENTION According to this invention, the semiconductor light-emitting device which made small the coupling loss to an optical fiber, an optical waveguide, etc. (for example, coupling loss is 4 dB or less) can be provided.

It is a top view of the LED light-emitting device of the Example of this invention. It is the top view and sectional drawing which expanded the recessed part vicinity of the LED light-emitting device. It is explanatory drawing of the plane curve of the reflective surface of the LED light-emitting device. It is a cross-sectional schematic diagram of the use condition of the LED light-emitting device. It is a figure of the plane curve of an Example and a comparative example.

  The LED light-emitting device 10 of the Example of this invention is demonstrated using FIGS.

  The LED light emitting device 10 is made of a LED element 11 and a copper alloy having a silver plating on the surface, the lead frame 12 on which the LED element 11 is placed on the upper surface, a transparent resin, and a lead. A sealing material 15 covering a part of the frame 12 and the LED element 11 is provided.

  The lead frame 12 has a recess 18 formed on the upper surface thereof by press working. The bottom surface 19 of the recess 18 is a substantially circular plane. This bottom surface 19 is a mounting surface on which the LED element 11 is mounted. The side surface 20 of the recess 18 is rotated on a plane curve 21 on a plane passing through the center of the bottom surface 19 and orthogonal to the bottom surface 19, passing through the center of the bottom surface 19, with the perpendicular of the bottom surface 19 being the rotation axis 17. It is a rotating surface whose inner diameter always increases toward the surface. The side surface 20 is a reflection surface that reflects the radiation light i of the LED element 11.

  The plane curve 21 is a curve that extends from the outer edge 19 c of the bottom surface 19 that appears in a cross section when the recess 18 is cut in a plane that passes through the center of the bottom surface 19 and is orthogonal to the bottom surface 19, and is located above the bottom surface 19. The first curve 22 below the intermediate point B and the second curve 27 above the intermediate point B.

  The LED element 11 has a substantially square plate shape and is placed at the approximate center of the bottom surface 19 with the light emitting surface facing upward. The radiated light i of the LED element 11 rises upward from the outer edge 19 c of the bottom surface 19, is reflected by the side surface 20 of the recess 18 surrounding the side of the LED element 11, and is guided to the opening of the recess 18. .

  Here, three types of LED light emitting devices 10 according to Examples having different shapes of the recesses 18 were prepared, and the respective coupling losses were measured. Moreover, three types of LED light emitting devices of comparative examples having different concave shapes were prepared, and their coupling loss was also measured. Table 1 below shows the shape of the recesses and the measured values of coupling loss in the examples and comparative examples. Each plane curve is shown in FIG. The LED element 11 has a height of 0.1 mm and a minimum distance between the corner 11b of the bottom surface and the outer edge 19c of the bottom surface 19 of the recess 18 is 0.03 mm.

  Describing each value in Table 1 in detail, the C point height H1 is the height from the bottom surface 19 to the upper end point C (opening of the recess 18) of the plane curve 21, that is, the depth of the recess 18; The point height H2 is the height from the bottom surface 19 to the middle point B of the plane curve 21, and the chip height H3 is the height from the bottom surface 19 to the upper surface 11a of the LED element 11. The bottom surface radius R is the radius of the circular bottom surface 19, and the gap G is the shortest distance from the bottom surface corner 11 b of the LED element 11 to the lower end point A of the planar curve 21.

  θ <b> 1 is an inferior angle among the intersection angles of the first straight line 23 extending from the lower end point A to the intermediate point B of the plane curve 21 and the perpendicular of the rotating shaft 17. S1 is the length of the first straight line 23, I1 is the length of the first perpendicular 24 that is the longest line among the perpendiculars of the first straight line 23 extending from the first straight line 23 to the first curve 22, and I1 / S1 is a value obtained by dividing the value of I1 by the value of S1. However, I1 takes a negative value when the first perpendicular 24 extends above the first straight line 23, that is, when the first curve 22 is a convex curve, and the first perpendicular 24 is below the first straight line 23. When the first curve 22 is a downwardly convex curve, it takes a positive value.

  θ <b> 2 is an inferior angle among the intersection angles of the second straight line 28 extending from the intermediate point B to the upper end point C of the plane curve 21 and the perpendicular of the rotating shaft 17. S2 is the length of the second straight line 28, and I2 is the length of the second vertical line 29 that is the longest line among the perpendicular lines of the second straight line 28 extending from the second straight line 28 to the second curve 27. Yes, I2 / S2 is a value obtained by dividing the value of I2 by the value of S2. However, I2 takes a negative value when the second perpendicular line 29 extends above the second straight line 28, that is, when the second curve 27 is a convex curve, and the second perpendicular line 29 becomes the second straight line 28. When it extends further downward, that is, when the second curve 27 is a downwardly convex curve, it takes a positive value.

  As shown in FIG. 4, the coupling loss is caused by interposing the glass plate 32 (thickness 0.1 mm) of BK7 in the LED light emitting device 10 in which the thickness of the sealing material 15 is 0.2 mm, and the optical fiber 30. When the outer diameter was 1.20 mm and the diameter of the core 31 was 0.98 mm, the ratio of the radiated light i of the LED element 11 that did not enter the optical fiber 30 was measured.

  As shown in Table 1, in Examples 1 to 3, the coupling loss was 3.6 dB or less, which was small. Moreover, insertion loss could be reduced. On the other hand, in Comparative Example 1 in which the value of I1 / S1 was 0.142 and Comparative Examples 2 and 3 in which θ1 was 90 °, the coupling loss was 4.1 dB or more.

  In addition, this invention is not limited to the said Example, In the range which does not deviate from the meaning of invention, it can change suitably and can be actualized.

DESCRIPTION OF SYMBOLS 10 LED light-emitting device 11 LED element 11a Upper surface 17 Rotating shaft 19 Bottom surface 19c Outer edge 20 Side surface 21 Plane curve 22 First curve 23 First straight line 24 First perpendicular line 27 Second curved line 28 Second straight line 29 Second perpendicular line A Bottom point B Middle point C Top point i Synchrotron radiation

Claims (3)

A semiconductor light emitting element (11), a circular mounting surface (19) on which the semiconductor light emitting element (11) is mounted, and the semiconductor light emitting device standing upward from an outer edge (19c) of the mounting surface (19). It surrounds the lateral side of the element (11), wherein possess a reflecting surface for reflecting (20) the emitted light (i) of the semiconductor light emitting element (11), communication incident radiation into an optical fiber or an optical waveguide The semiconductor light emitting device (10) of
The reflection surface (20) passes through the center of the placement surface (19) through a plane curve (21) on a plane passing through the center of the placement surface (19) and orthogonal to the placement surface (19). It is a rotating surface in which the inner diameter is always increased toward the top, which is rotated with the line as the rotation axis (17),
The plane curve (21) includes a first curve (22) extending from a lower end point (A) on the outer edge (19c) to an intermediate point (B) above the lower end point (A), and the intermediate point A second curve (27) extending from (B) to the upper end point (C) which is above the intermediate point (B) and is the upper end of the reflecting surface (20);
Of the intersecting angles between the perpendicular line of the rotation axis (17) and the first straight line (23) extending from the lower end point (A) to the intermediate point (B), the minor angle θ1 is 56.61 ° ≦ θ1 ≦ 74. .63 °,
The length I1 of the longest first perpendicular (24) of the first straight line (23) extending from the first straight line (23) to the first curved line (22) (where I1 is the first perpendicular to the first straight line) A value obtained by dividing a negative value when extending further upward and a positive value when the first perpendicular extends below the first straight line by the length S1 of the first straight line (23), −0.011 ≦ I1 / S1 ≦ 0.110,
Of the intersecting angles between the perpendicular line of the rotating shaft (17) and the second straight line (28) extending from the intermediate point (B) to the upper end point (C), the minor angle θ2 is 63.74 ° ≦ θ2. ≦ 66.30 °,
The length I2 of the longest second perpendicular (29) of the second straight line (28) extending from the second straight line (28) to the second curve (27) (where I2 is the second perpendicular When it extends above the second straight line, it takes a negative value, and when the second perpendicular extends below the second straight line, it takes a positive value) by the length S2 of the second straight line (28). A semiconductor light emitting device, wherein the divided value is 0.041 ≦ I2 / S2 ≦ 0.078. The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting element (11) has a substantially square plate shape in a plan view and a rectangular plate shape in a side view . A height H2 from the placement surface (19) to the intermediate point (B) is 0.7 to a height H3 from the placement surface (19) to the upper end (11a) of the semiconductor light emitting element (11). 3. The semiconductor light emitting device according to claim 1 or 2 , wherein the semiconductor light emitting device is 1.25 times.

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