JP2000133834A - Optical semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical semiconductor device with high signal intensity by employing the focal design of a lens which takes into consideration the reflection on a reflective surface, related to a device wherein an optical signal is deflected on a reflective surface with a lens provided on the side surface of a sealing body. SOLUTION: Light-receiving elements 2 and 3 are fixed on islands 21 and 22, which is molded with a transparent resin to provide a sealing body 24. A groove 26 is formed at the upper part of each element 2 and 3 to form a reflecting surface 27, and a signal light 6 is reflected on the reflecting surface 27 and allowed to enter/exit from one side surface 25b of the sealing body 25. A lens 28 is provided on one side surface. A centerline 41 of the lens 28 is positioned almost at the center of the pattern of a photodiode PD and the reflecting surface 27. The focal point of the lens 28 is positioned almost on the surface of these elements after taking deflection on the reflection surface 27 into due consideration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device in which 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 data communication according to the IrDA standard, 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. 4 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 apparatus main body 1 of FIG. 4 is mounted so that the optical signal 6 is introduced in a direction perpendicular to the printed circuit board, the height of the apparatus 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, as shown in FIG. 5, 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 to make the lenses 4 and 5 horizontal. 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 a semiconductor element having a light receiving surface or a light emitting surface for converting an optical signal into an electric signal is covered with a resin layer. An optical semiconductor device that forms a reflection surface with the resin layer, bends an optical signal at the reflection surface, and transmits and receives the optical signal from one side surface of the resin layer, wherein one side surface of the resin layer A lens body for condensing the optical signal,
A center line of the lens body substantially coincides with a center of a light receiving surface or a light emitting surface of the semiconductor element via the reflection surface.

[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, the light receiving element 2 and the light emitting element 3 are housed in one package. FIG. 1 is a plan view showing the structure of the present invention.
FIG. 2A is a cross-sectional view showing a cross-sectional view of the light emitting element 3 and FIG.
(B) is a sectional view of the light receiving element 2 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. Aluminum electrode pads 30 are formed on the surface of the semiconductor chip, and the electrode pads 30 and the lead terminals 23 are connected by bonding wires 24.

The light emitting element 3 is an LED provided as a semiconductor chip and emitting, for example, infrared light having a wavelength of 870 nm.
Chip. An 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 optical signal 6 from the light emitting element 3 fixed to the center of the island 22 is reflected by the inclined side wall of the “bowl”. In this way, the light is collected in one direction. The island 22 serves as one terminal of the anode (A) or the cathode (B) of the light emitting element 3, and the electrode pad 30 formed on the chip surface serves as the other terminal.

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 at least infrared light, including the tip of the lead 23. The resin layer forms the sealing body 25 and the sealing body 2
5, the back surface of the islands 21 and 22 is the sealing body 2
5 Exposed in the same plane as the surface.

The lead terminal 23 is connected to the other side surface 25 of the sealing body 25.
derived from a to be suitable for surface mounting applications,
It is bent in a Z-shape.

A groove 26 is formed in the upper part of the light emitting element 3 by denting the resin of the sealing body 25 to a predetermined depth, and a flat reflecting surface 27 is formed by the side wall of the groove 26. The reflection surface 27 is formed by forming a male portion corresponding to the groove 26 in a mold when transfer molding the sealing body 25, or shaving the surface of the sealing body 25 after completion. It is formed by things. And the reflection surface 27
The signal light 6 emitted from the light emitting element 3 has a function of being reflected by the reflection surface 27 and emitted from one side surface 25b of the sealing body 25 to the outside.

On one side face 25b of the sealing body 25, a lens 28 for condensing the emitted light signal 6 is formed integrally with the sealing body 25. The lens 28 is, for example, a hemisphere designed with a predetermined radius, and its focal point is located near the surface of the light emitting element 3 in consideration of the reflection on the reflection surface 27.

On the other hand, similarly to the light emitting element 3, a groove 26 and a reflection surface 27 are formed above the light receiving element 2 side. The reflecting surface 27 formed on the upper part of the light receiving element 3 has a function of reflecting the optical signal 6 introduced from one side surface 25b of the sealing body 25 on the reflecting surface 27 and reaching the photodiode portion PD of the light receiving element 2. . A lens 28 is also formed of a resin layer on one side surface 25b of the sealing body 25, and collects an optical signal 6 incident from the outside.

These reflecting surfaces 27 become reflecting surfaces due to the difference in the refractive index of the material at the boundary. for that reason,
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. Reflective surface 2 to improve reflectivity
7 may be covered with a light-shielding metal film or the like.

The reflecting surface 27 has an inclination angle of about 45 degrees with respect to the surface of the semiconductor chip, and the entire surface of the photodiode portion PD and the chip of the light emitting element 3 are viewed in plan view (observed as shown in FIG. 1). It is formed so as to cover the entire surface. As a result, the deepest portion of the groove 26 is located on the other side surface 25a side with respect to the photodiode portion PD of the light emitting element 3 and the light receiving element 2.
The position of the deepest part of the groove 26 substantially coincides with the light emitting element 3 side and the light receiving element 2 side.

The lens 28 is formed of a spherical body having a radius of 1.8 mm, for example, when the height of the sealing body 25 (FIG. 2A: t in the drawing) is 2.5 mm, and protrudes upward and downward. The portion is cut into a flat surface 25a. When viewed in a plan view (observed as shown in FIG. 1), the center line 41 connecting the foremost portion 40 of the lens 28 and the focal point of the lens 28 is reflected by the reflection surface 27 and the light receiving pattern of the photodiode PD. To reach almost the center of. When viewed in a cross-sectional view along the center line 41 (observed as shown in FIG. 2B), the lens 28
A center line 41 connecting the foremost portion 40 of the lens and the focal point of the lens 28
Is reflected by the reflection surface 27 and reaches almost the center of the light receiving pattern of the photodiode PD. Locations that do not conform to this design are provided with an inclination angle such that the reflected light does not reach each element, like the second slope 27a of the groove 26.

FIG. 3 shows a state in which the lens 28 is observed from one side surface 25b of the sealing body 25. Lens 28
Is located at the center of the reflecting surface 27 and substantially at the center of the light receiving pattern of the photodiode PD projected on the reflecting surface 27. The situation is the same on the light emitting element 3 side, so that the center line 41 of the lens 28 is located substantially at the center of the reflection surface 27 and reaches almost the center of the pattern of the light emitting element 3 projected on the reflection surface 27. The positional relationship between the three is designed (shown in FIG. 2A). Then, along these center lines 41, the sum of the distance from the lens 28 to the reflecting surface and the distance from the reflecting surface 27 to the surface of the photodiode PD or the surface of the light emitting element 2 substantially match the focal point of the lens 28. Design is made.

According to such a design, a portion having the highest light intensity of the optical signal 6 condensed by the lens 28 can be concentrated on the light receiving element 2, so that the receiving sensitivity of the photodiode PD can be increased. The light signal 6 having a high light intensity can also be emitted from the light emitting element 3 side. Further, the reflection surface 2
By making the centers coincide with each other also with respect to 7, it is possible to secure a wide range that can be received by the reflection surface 27 when the optical signal 6 enters from a direction shifted from the center line 41.

As described above, the semiconductor device of the present invention can be configured by bending the transmission path of the optical signal 6
A semiconductor device in which the thickness t of the sealing body 25 is small can be obtained. Thereby, when such a device is surface-mounted on a printed circuit board, the height of the entire printed circuit board can be kept low, and furthermore, the optical signal 6 can be emitted to and emitted from the printed circuit board in the horizontal direction. It can promote the thinning of electronic devices.

[0024]

As described above, according to the present invention, by providing the reflecting surface 27 with the groove 26, there is an advantage that an optical semiconductor device capable of transmitting and receiving the optical signal 6 from the side surface 25b of the resin can be realized. In this device, the overall thickness t 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 matching the focus design of the lens 28 to the photodiode PD or the substantially central portion of the light emitting element 3, there is an advantage that the optical signal 6 with high light intensity can be transmitted and received.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating the present invention.

FIG. 2 is a sectional view illustrating the present invention.

FIG. 3 is a diagram for explaining the present invention.

FIG. 4 is a perspective view illustrating a conventional example.

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

Continuation of the front page (72) Ko Ochiai 2-5-2-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Hiroshi Inoguchi 2-5-2-5 Keihanhondori, Moriguchi-shi, Osaka Inside Sanyo Electric Co., Ltd. (72) Inventor Tsutomu Ishikawa 2-5-2-5 Keihanhondori, Moriguchi-shi, Osaka Prefecture Inside Sanyo Electric Co., Ltd. (72) Inventor Satoshi 2-5-2 Keihanhondori, Moriguchi-shi, Osaka Prefecture No. 5 Sanyo Electric Co., Ltd. (72) Inventor Hiroshi Kobori 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 5F041 AA39 AA47 CB32 DA57 EE23 FF16 5F088 AA01 BA15 BB10 EA09 JA11 5F089 AA03 AC10 AC11 BC02 BC11 BC15 BC23 BC24 CA16 CA20 EA04

Claims (4)

[Claims] 1. A semiconductor element having a light receiving surface or a light emitting surface for converting an optical signal into an electric signal is covered with a resin layer, and a reflection surface is formed by the resin layer above the semiconductor element. An optical semiconductor device that bends an optical signal and transmits and receives the optical signal from one side surface of the resin layer, comprising: a lens body that collects the optical signal on one side surface of the resin layer; Wherein the center line substantially coincides with the center of the light receiving surface or the light emitting surface of the semiconductor element via the reflection surface. 2. The optical semiconductor device according to claim 1, wherein a center line of said lens body also coincides with a center of said reflection surface. 3. The optical semiconductor device according to claim 1, wherein said light receiving element is an integrated circuit, and includes a photodiode for receiving light and a peripheral driving circuit for said photodiode. 4. The semiconductor device according to claim 1, wherein said lens body is integrated by said resin layer.