JPH10321900A - Optical module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To monitor light intensity, without sacrificing radiated light. SOLUTION: A light-emitting element LD and a light-receiving element PD mounted on a lead frame 10 are integrally sealed by a resin which is transparent with respect to the wavelength of a light radiated from the light-emitting element. In a resin molded portion 12, a condenser lens 14 aligned with an optical axis with the light-emitting element LD, and reflection surfaces 16, 18 located at positions which deviate from the optical axis on the periphery of the condenser lens 14 and adapted for reflecting unnecessary leakage light of the radiated light to the light-receiving element PD are formed. The condenser lens 14 and the reflection surfaces 16, 18 are formed at the same time by a metal mold in resin sealing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module including a light emitting element and a light receiving element for observing the intensity of light emitted from the light emitting element.

[0002]

2. Description of the Related Art An optical module for introducing light into an optical waveguide such as an optical fiber comprises a light emitting element for emitting light and a light receiving element for monitoring the actual intensity of the emitted light. Feedback control such as maintaining the output light of the light emitting element at an optimum intensity based on the monitor output of the light receiving element is enabled.

In a conventional optical module, as shown in FIG. 5A, light is emitted from a light emitting surface AR into a module housing 2 and introduced into an optical fiber FB or the like via collimating lenses 4 and 6. Light emitting element LD such as an edge emitting semiconductor laser, and a rear end face HR (High Reflectivit
y) That is, a light receiving element PD is provided opposite to the rear end face HR that constitutes a resonator together with the light exit surface AR, and light leaking from the rear end face HR is monitored by the light receiving element PD. .

In another optical module, FIG.
As shown in FIG. 1, a half mirror 8 is arranged in the optical axis of the light emitted from the light emitting element LD, and the light split by the half mirror 8 is monitored by the light receiving element PD.

[0005]

However, FIG.
In the conventional optical module shown in (a), when the edge emitting light emitting element LD is mounted on a coaxial module, it is necessary to provide a monitor light receiving element PD behind the light emitting element LD such as a semiconductor laser chip. However, there is a problem that a special package needs to be specially mounted. Furthermore, in this optical module, when a surface-emitting light emitting element LD is used, it is substantially impossible to provide a monitoring light receiving element PD behind the light emitting element LD.

In the conventional optical module shown in FIG. 5B, since the half mirror 8 is provided in the optical axis, the structure becomes complicated or the amount of emitted light introduced into optical communication or the like is sacrificed. There was a problem of doing.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and it is possible to reliably monitor the light intensity with a light receiving element regardless of whether an edge emitting type or a surface emitting type is used. The purpose is to provide a module.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a light emitting device and a light receiving device mounted on a substrate with respect to the wavelength of light emitted from the light emitting device. In an optical module integrally sealed with a transparent resin, a surface of the resin that integrally seals the light emitting element and the light receiving element, and a portion deviated from an optical axis of the light emitting element, is provided from the light emitting element. It is configured to include a reflection unit that reflects leaked light of the emitted light to the light receiving element.

[0009]

In the light emitting device, only unnecessary leakage light out of the light emitted from the light emitting device is reflected by the reflection means provided at a portion shifted from the optical axis of the light emitting device and is monitored.
Light necessary for optical communication or the like does not pass through the reflection means, and is emitted without sacrificing the light amount. These functions can be obtained by using a structure using any of a light emitting element of a surface emitting type and an edge emitting type. When the light emitting element and the light receiving element are integrally sealed with a transparent resin using a mold, the reflecting means can also be integrally formed with the resin, thereby simplifying the manufacturing process.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical module according to the present invention will be described below with reference to FIGS. FIG. 1 is a longitudinal sectional view schematically showing the structure of the optical module.
FIG. 3 is a vertical cross-sectional view taken along a virtual plane including a normal to a light emitting surface of a light emitting element and a normal to a light receiving surface of a light receiving element. 2 to 4 are vertical cross-sectional views schematically showing the structure of the modified example.

In FIG. 1, a lead frame 1 made of metal is used.
0, a light emitting element LD such as a surface emitting semiconductor laser or a light emitting diode and a light receiving element PD such as a photodiode or a Schottky diode are arranged at predetermined intervals in a bare chip state. Is fixed by die bonding, and bonding pads and lead frames 1 provided on the respective elements LD and PD are further fixed.
0 and a predetermined internal lead are connected by wire bonding.

A lead frame 10 to which wire bonding has been performed is mounted on a mold, and a light emitting element LD and a light receiving element PD are mounted.
By integrally sealing the element mounting portion of the lead frame 10 with a resin, the resin molded portion 12 having a shape matched to the mold is integrated.

As the sealing resin, a material transparent to the wavelength of the light emitted from the light emitting element LD is used, and the light emitting surface a of the light emitting element LD and the optical axis The combined convex lens 14 having a convex shape on the outside and the condenser lens 1
4, reflection surfaces 16 and 18 are formed on the periphery.

The reflecting surfaces 16 and 18 are flat surfaces of an appropriate shape formed on the resin surface at portions deviated from the optical axis Q of the light emitting element. Among the light emitted from the light emitting element LD at a radiation angle, The light beam is formed at a predetermined inclination angle so as to reflect a light beam (hereinafter, referred to as leakage light) excluding the light beam passing through the condenser lens 14. Then, due to the difference between the inclination angle and the refractive index between the resin and the outside air, the leaked light incident on the reflection surfaces 16 and 18 is almost totally reflected and is incident on the light receiving element PD.

Also, as an optional matter, the reflecting surfaces 16,
A structure is adopted in which the outer surface of the light-emitting element 18 is coated with a metal thin film so that the total reflection of the leaked light toward the light receiving element PD is further ensured. Further, the reflecting surfaces 16 and 18 are provided not only at the two positions sandwiching the condenser lens 14 along the arrangement direction of the light emitting element LD and the light receiving element PD, but also at the outer periphery of the condenser lens 14 to receive the leakage light. There is also adopted a structure in which a reflection surface for reflecting light toward the element PD is formed in an arc shape.

Next, a structure of a modification will be described with reference to FIG. In FIG. 2, the same or corresponding parts as those in FIG. 1 are indicated by the same reference numerals. The difference between the optical module shown in FIG. 1 and FIG. 2 is as follows. In FIG. 2, the reflecting surfaces 20 and 22 located on the periphery of the condenser lens 14 are both a light emitting surface a of the light emitting element LD and a light receiving surface of the light receiving element PD. It is formed in a concave curved surface toward b. In other words, by forming the surface of the resin molded part 12 to have a convex curved surface toward the outside, due to the difference in the refractive index between the resin and the outside air, the concave curved reflective surface 20, 22 are realized. These reflection surfaces 20 and 22 are also formed at portions deviated from the optical axis Q of the light emitting element, and the light flux (excluding the light flux passing through the condenser lens 14) of the light emitted from the light emitting element LD at a radiation angle. The reflected light is reflected and condensed by a concave curved surface, and is emitted to the light receiving surface b of the light receiving element PD.

Further, by coating the outer surfaces of the reflecting surfaces 20 and 22 with a metal thin film, total reflection of the leaked light to the light receiving element PD side can be made more reliable, or the reflecting surfaces 20 and 22 can be more reliably reflected.
2 are provided not only at two places with the condenser lens 14 interposed along the arrangement direction of the light emitting element LD and the light receiving element PD, but also on the outer periphery of the condenser lens 14 to reflect the leaked light toward the light receiving element PD. There is also adopted a structure in which a reflecting surface to be formed is formed in an arc shape.

Next, another modified example will be described with reference to FIG. 3 and FIG. 3 and 4, the same or corresponding parts as those in FIGS. 1 and 2 are denoted by the same reference numerals. The optical module shown in FIGS. 1 and 2 uses a surface-emitting type light emitting element. The optical module shown in FIGS. 3 and 4 has a light emitting element L such as an edge emitting type semiconductor laser or a light emitting diode.
D is used. This end emission type light emitting element LD
The light emitting surface a is aligned with the condenser lens 14 in optical axis, and is fixed to a side end of a chip carrier member 24 fixed to the lead frame 10. Then, the reflecting surface 16, 18, or 20, 2, 2 having the same shape as in FIGS.
2. Alternatively, the emitted leakage light is reflected to the light receiving surface b of the light receiving element PD by the reflecting surface formed in an arc shape on the peripheral edge of the condenser lens 14, and the intensity of the emitted light can be monitored. ing.

In the embodiment including the modification described above, the light emitting element LD and the light receiving element P are provided on the lead frame.
D is mounted, but at least the light emitting element LD
Also, the present invention can be applied to an optical module in which an insulating substrate provided with an electric wiring pattern on the mounting surface side of the light receiving element PD, for example, a hybrid integrated circuit substrate is integrally sealed with a transparent resin.

[0020]

As described above, according to the present invention, a reflection means is provided at a portion shifted from the optical axis of a light emitting element, and only unnecessary leakage light out of light emitted from the light emitting element is transmitted to the light receiving element. Since the light is reflected, the intensity of the emitted light can be monitored without sacrificing the amount of light necessary for optical communication or the like. Further, this effect can be applied to a coaxial module using a surface-emitting type light-emitting element, regardless of the structure using either a surface-emitting type or an edge-emitting type light-emitting element.

Further, by integrally sealing the light emitting element and the light receiving element with a transparent resin using a mold, the reflecting means can be formed integrally with the resin, thereby simplifying the manufacturing process. And the like.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a structure of an embodiment.

FIG. 2 is a longitudinal sectional view showing a structure of a modification of the embodiment.

FIG. 3 is a longitudinal sectional view showing the structure of another modification of the embodiment.

FIG. 4 is a longitudinal sectional view showing a structure of still another modification of the embodiment.

FIG. 5 is an explanatory view schematically showing the structure of a conventional optical module.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Lead frame, 12 ... Resin molding part, 14 ... Condensing lens, 16, 18, 20, 22 ... Reflection surface, 24 ... Chip carrier member, LD ... Light emitting element, PD ... Light receiving element, a
... light emitting surface, b ... light receiving surface.

Claims (9)

[Claims] 1. An optical module comprising a light emitting element and a light receiving element mounted on a substrate integrally sealed with a resin substantially transparent to a wavelength of light emitted from the light emitting element. A part of the surface of the resin which integrally seals the light emitting element and the light receiving element and which is off the optical axis of the light emitting element reflects leakage light of light emitted from the light emitting element to the light receiving element. An optical module comprising a reflection unit. 2. The optical module according to claim 1, wherein the reflection unit is a flat reflection surface that reflects light leaked from the light emitting element to a light receiving surface of the light receiving element. 3. The reflection means reflects the light leaked from the light emitting element to a light receiving surface of the light receiving element, and forms a concave surface toward the light emitting surface of the light emitting element and the light receiving surface of the light receiving element. The optical module according to claim 1, wherein the optical module is a surface. 4. The reflection means is characterized in that a surface portion of the resin on which the reflection surface is formed is coated with a metal film that totally reflects light leaked from the light emitting element. Or the optical module according to any one of 3. 5. A light collecting means which is aligned with an optical axis of the light emitting element is integrally formed on a portion of the surface of the resin other than the reflecting means.
The optical module according to any one of the above. 6. The optical module according to claim 1, wherein the substrate is a lead frame on which the light emitting element and the light receiving element are mounted. 7. The optical module according to claim 1, wherein the substrate is an insulating substrate provided with an electric wiring pattern on at least a mounting surface of the light emitting element and the light receiving element. 8. The optical module according to claim 1, wherein the light emitting device is a surface light emitting type light emitting device. 9. The light according to claim 1, wherein the light-emitting element is an edge-emitting light-emitting element, and is mounted on the substrate via a chip carrier member. module.