JP2000068531A - Optical semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical semiconductor device having increased light condensing efficiency, by a method wherein the semiconductor device is thinly formed by transmitting an optical signal from the side wall of a package and by the combination of surface reflection and a lens. SOLUTION: When at least a light receiving element 2 is fixed to an island 21 and a sealed body 25 is formed by sealing the circumference using a transparent resin. A reflection surface 27 is formed above the light receiving element 2, and a lens 28 is formed on the side face 25b of the sealed body 25. An optical light 6 is made incident from the lens 28, the signal light 6 is reflected by a reflection surface 27 and it reaches the photodiode PD of the light receiving element 2. Besides, the reflection surface 27 and the lens 28 are formed into cylindrical curved surface, and an optical signal 6 is condensed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor device in which a light receiving element or a light emitting element and a light receiving element are sealed with a resin, and more particularly to a thin device.

[0002]

2. Description of the Related Art Recently, multimedia equipment such as a sub-notebook personal computer, a portable information terminal, and an electronic still camera has been remarkably developed. These devices are required to be easy to transmit and receive data to and from the outside because they are required to be portable, and equipped with a device that connects the external device and the main unit in a cordless manner by using optical signals such as infrared rays. There are many. Among them, the IrDA (Infrared Data Association) standard using infrared light having a wavelength of 870 nm as an optical signal is most widely used.

In order to use IrDA communication, both devices to be connected need to be provided with a light emitting element for emitting an infrared signal and a light receiving element for receiving an infrared signal. The light emitting element and the light receiving element may be incorporated in the electronic device as separate packages, respectively, or both may be supplied as a module housed in one package.

FIG. 5 shows an example of a semiconductor device for infrared data communication in which a light emitting element and a light receiving element are housed in one package (for example, Japanese Patent Application Laid-Open No. H10-70304). In this device, a light receiving element 2 and a light emitting element 3 provided in the form of a semiconductor chip are housed in a device main body 1, and are molded with a resin transparent to at least infrared rays. In particular, in the light receiving element 2, the photodiode PD for light reception and peripheral circuits such as an amplifier circuit may be integrated in the same chip.

The photodiode PD of the light receiving element 2 provided on a semiconductor chip has a structure for receiving light in a direction perpendicular to the surface of the semiconductor chip. Therefore, both the light receiving element 2 and the light emitting element 3 are configured to emit / receive the optical signal 6 perpendicular to the semiconductor chip.
Hemispherical lenses 4 and 5 are formed of resin above each element for condensing light.

[0006]

In order to meet the demand for lighter, thinner and smaller electronic devices, it is essential to limit the height of the electronic component itself fixed on the printed circuit board. However, when the device main body 1 of FIG. 5 is mounted so that the optical signal 6 is introduced in a direction perpendicular to the printed circuit board, the height of the device main body 1 is increased due to the presence of the lenses 4 and 5, and the overall thickness is reduced. There was a drawback that was difficult.

On the other hand, it is also possible to introduce the optical signal 6 in the horizontal direction with respect to the printed circuit board 7 by bending the leads and turning the lenses 4 and 5 sideways as shown in FIG. However, since the semiconductor chips of the light receiving element 2 and the light emitting element 3 are mounted so as to stand vertically, it is impossible in principle to make the mounting height less than the size of the semiconductor chip. There was a drawback that shaping was difficult.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a light-receiving element in which a light-receiving element for converting an optical signal into an electric signal is sealed inside a sealing body through which the optical signal can be transmitted. In the semiconductor device, a reflection surface that reflects an optical signal incident from a side surface of the sealing body and reaches the light receiving diode is formed on the sealing body above the light receiving diode, and a sealing surface on which the optical signal is incident. By forming a convex lens on the side surface of the stationary body and combining the reflection surface and the convex lens, light is collected in the vertical direction and the light in the horizontal direction with respect to the surface of the light receiving element. It is characterized by the following.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. In this embodiment mode, a light receiving element 2 and a light emitting element 3 are housed in one package. FIG. 1A is a plan view showing a structure of the present invention.
FIG. 1B is a sectional view taken along line AA, and FIG. 2 is a perspective view showing a main part.

In these figures, 21 is an island on which the light receiving element 2 is mounted, 22 is an island on which the light emitting element 3 is mounted, and 23 is a lead terminal for external connection.
These are provided by a lead frame made of an iron or copper-based material, and the light receiving element 2 and the light emitting element 3 are fixed to the surface of each of the islands 21 and 22 with an adhesive such as solder.

The light receiving element 2 is a PIN photodiode or the like provided as a semiconductor chip, and a peripheral driving circuit or the like may be integrated on the same chip. Reference numeral PD in the drawing indicates a photodiode portion (light receiving surface) of the light receiving element 2. Electrode pads are formed on the surface of the semiconductor chip, and the electrode pads and the leads 23 are connected by bonding wires 24.

The light emitting element 3 is, for example, an LED diode chip that emits infrared light having a wavelength of 870 nm. LED
Is an element that emits light in the entire chip and emits light in all directions. Therefore, the island 22 to which the chip is fixed is processed into a shape like a conical “bowl”, and the island 22 is fixed.
The optical signal 6 from the light emitting element 3 fixed to the center of the island 22 is reflected upward by the inclined side wall of the island 22 to collect light. The island 22 serves as one terminal of the anode or the cathode, and the electrode pad formed on the chip surface serves as the other terminal. The electrode pad serving as the other terminal is connected to a predetermined location by a bonding wire 24.

The light emitting element 2 and the light receiving element 3 fixed to each of the islands 21 and 22 are transfer-molded with a resin transparent to infrared light or ultraviolet light including the tip of the lead 23. The resin forms the sealing body 25, and the back surfaces of the islands 21 and 22 are exposed on one surface of the sealing body 25 so as to be flush with the surface of the sealing body 25. The lead 23 is led out from the middle of one side surface 25a of the sealing body 25, and is bent in a Z-shape so as to be suitable for surface mounting use.

Thus, a groove 26 in which a resin is recessed is formed above the photodiode portion PD of the light receiving element 2.
The reflecting surface 27 is constituted by the side wall of the sixth. A convex lens 28 is formed on the other side surface 25b of the sealing body 25. The vicinity of the reflection surface 27 and the convex lens 28 is shown in FIG.

Referring to FIG. 2, the reflecting surface 27 has a substantially cylindrical concave curved surface (of the sealing body 25) having a focal point at the surface of the photodiode portion PD of the light receiving element 2 or at a position slightly deeper than the surface. (Observed from inside))
Is formed in such a shape as to have a center line 29 extending in the horizontal direction (x direction in the drawing) and a radius r1 with respect to the surface. The concave curved surface may be formed by forming a male portion corresponding to the groove 26 in the mold when transfer molding the sealing body 25, or may be performed after the sealing body 25 is completed.
Formed by shaving the surface of

The reflecting surface 27 serves to reflect the optical signal 6 introduced from the other side surface 25b of the sealing body 25 and reach the photodiode portion PD of the light receiving element 2. At this time, by making the reflection surface 27 parabolic, more light signals 6 are collected on the surface of the photodiode portion PD. The reflection surface 27 plays a role of condensing the optical signal 6 in a direction perpendicular to the surface of the light receiving element 2 (z direction). This can be clearly understood from the path of the optical signal 6 indicated by an arrow in FIG.

On the other hand, the lens 28 formed on the other side surface 25b of the sealing body 25 is positioned on the surface of the photodiode portion PD of the light receiving element 2 or at a position slightly deeper in consideration of the reflection on the reflection surface 27. Has a side wall substantially perpendicular to a substantially cylindrical convex curved surface (observed from the outside of the device) having a focal point, and extends in a direction perpendicular to the surface of the light receiving element 2 (z direction in the drawing). And has a radius r2. It is convenient to form the convex curved surface so as to be integrated with the sealing body 25 when the sealing body 25 is sealed with a resin.

The lens 28 condenses the optical signal 6 introduced from the other side surface 25b of the sealing body 25 in the horizontal direction (x direction in the figure) along the surface of the light receiving element 2. Play a role. That is, light is collected along a plane parallel to the surface of the light receiving element 2. This can be clearly understood from the path of the optical signal 6 indicated by an arrow in FIG.

The light signal 5 is condensed by the reflecting surface 27 and the convex curved surface 28 so that the photodiode PD
Can be incident. This means that the reception sensitivity of the optical signal 6 is increased and the propagation distance is increased. In addition, by providing the light collecting function in the vertical direction to the reflection surface 27, the lens 28 can share only the light collecting function in the horizontal direction. Therefore, by processing the lens 28 into a cylindrical shape, there is an advantage that the surface area on which the optical signal 6 can be incident can be increased as compared with the case where a spherical lens is provided in the same projection area.

The reflecting surface 27 is a reflecting surface due to the difference in the refractive index of the material at the boundary. Therefore, while the entire sealing body 25 is matte-finished, the surfaces of the reflection surface 27 and the lens 28 are mirror-finished with smaller surface roughness. The reflection surface 27 may be covered with a light-shielding metal film or the like in order to improve the reflectance.

Furthermore, the convex lens 28 may have a side wall having a taper angle of 1 to 5 degrees in consideration of the releasability of the resin from the upper and lower molds. This taper angle θ is provided both upward and downward about the position of the lead 23, and is clearly understood from the description of FIGS. 1A and 1B.

In addition to the light receiving element 2, a reflection surface 40 and a convex lens 41 are similarly arranged on the light emitting element 3 side.
The light receiving element 2 is provided separately from the light receiving element 2 in order to make the design such as the curvature different. It has a function of reflecting the signal light 6 emitted from the light emitting element 3 on the reflection surface 40 and emitting the signal light 6 to the outside from the side wall 25 b of the sealing body 25 via the lens 41. It is said that the light is condensed in the horizontal direction by the lens 41 to have a certain degree of directionality.
It has the same function as the light receiving element 2 side. By condensing the signal light 6 with the reflection surface 40 and the lens 41, the propagation distance of the signal light 6 can be increased.

By bending the transmission path of the optical signal 6 as described above, the optical signal 6 can be propagated from the side surface 25b of the sealing body 25 when the device is surface-mounted on a printed circuit board. The height of the entire printed circuit board can be kept low, and thinning of electronic devices can be promoted.

The optical semiconductor device may be a device in which both the light receiving element 2 and the light emitting element 3 are sealed, or a device in which either one is sealed.

FIG. 3 shows a second embodiment of the present invention. Instead of providing the groove 26 as a configuration for obtaining the reflection surface 27, the portion where the reflection surface 27 is formed is made to protrude in a convex shape. Further, the reflection surface 27 and the reflection surface 40 may be constituted by one continuous curved surface without being separated. The same reference numerals are given to the same portions as those in the previous embodiment, and the description is omitted.

FIG. 4 shows a third embodiment of the present invention. The functions of the reflection surface 27 and the lens 28 are reversed.
The reflection surface 27 performs light collection in the horizontal direction (x direction), and the lens 28 performs light collection in the vertical direction (z direction). The same reference numerals are given to the same portions as those in the previous embodiment, and the description is omitted.

[0027]

As described above, according to the present invention,
Since the optical signal 6 is reflected and reaches the light receiving element 2 by providing the reflection surface 27, the side surface 25 of the resin is used.
This has an advantage that an optical semiconductor device capable of entering and exiting the optical signal 6 from b can be realized. In this device, the overall height of the sealing body 25 can be reduced, so that when the device is mounted on a printed circuit board, the thickness can be significantly reduced.

Further, by separating each function such that light is collected in the vertical direction on the reflection surface 27 and light is collected in the horizontal direction by the lens 28, the surface area of the lens 28 is increased.
There is also an advantage that the sensitivity of the device can be increased by increasing the amount of the optical signal 6 that can be collected.

[Brief description of the drawings]

FIG. 1A is a plan view illustrating a first embodiment,
(B) It is sectional drawing.

FIG. 2 is a perspective view illustrating a first embodiment.

FIG. 3A is a plan view illustrating a second embodiment,
(B) It is sectional drawing.

FIG. 4 is a perspective view illustrating a third embodiment.

FIG. 5 is a perspective view illustrating a conventional example.

FIG. 6 is a perspective view illustrating a conventional example.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tsutomu Ishikawa 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Satoshi Sekiguchi 2-5-2 Keihanhondori, Moriguchi-shi, Osaka No. 5 Sanyo Electric Co., Ltd. (72) Inventor Hideo Kunii 2-5-Keihanhondori, Moriguchi-shi, Osaka 2-5-5 Sanyo Electric Co., Ltd. (72) Inventor Kiyoshi Takada 2 Keihan-hondori, Moriguchi-shi, Osaka 5-5-5 Sanyo Electric Co., Ltd. (72) Inventor Hiroshi Inoguchi 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 5F041 AA01 AA06 CB32 DA26 DA55 DA57 EE21 5F088 AA03 BA20 EA09 JA02 JA06 JA11 JA12

Claims (8)

[Claims] 1. Inside a sealing body through which an optical signal can be transmitted,
In an optical semiconductor device in which a light receiving element for converting the optical signal into an electric signal is sealed, a reflection surface for reflecting an optical signal incident from a side surface of the sealing body and reaching the light receiving diode on the light receiving element. Forming a convex lens on the side surface of the sealing body on which the optical signal is incident, and combining the reflective surface and the convex lens to form a convex lens in a direction perpendicular to the surface of the light receiving element. An optical semiconductor device which performs light collection and light collection in a horizontal direction. 2. The optical semiconductor device according to claim 1, wherein said reflecting surface is a cylindrical concave curved surface, and said lens is a cylindrical convex curved surface. 3. The optical semiconductor device according to claim 1, wherein the reflection surface performs the light collection in the vertical direction, and the convex lens performs the light collection in the horizontal direction. 4. The optical semiconductor device according to claim 1, wherein said reflection surface focuses light in said horizontal direction, and said convex lens focuses light in said vertical direction. 5. The optical semiconductor device according to claim 1, wherein the reflection surface is formed on a resin surface of the sealing body. 6. The method according to claim 5, wherein the reflection surface is formed by an inner wall of a groove formed on a surface of the sealing body.
The optical semiconductor device according to the above. 7. The optical semiconductor device according to claim 1, wherein the convex lens is formed of a resin integrated with the sealing body. 8. Inside a sealed body through which an optical signal can be transmitted,
In an optical semiconductor device in which a light emitting element that emits an optical signal from an electric signal is sealed, a reflection surface is formed above the light emitting element to reflect an optical signal emitted from the light emitting element in a horizontal direction with respect to the light emitting element. Then, a convex lens is formed on a side surface of the sealing body from which the optical signal is emitted, and by combining the reflection surface and the convex lens, light is condensed in a direction perpendicular to the surface of the light emitting element. And an optical semiconductor device for condensing light in a horizontal direction.