JPH0843692A - Light emitting element module - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] It is an object of the present invention to provide a light-emitting element module capable of further suppressing return light in each optical component constituting the module. [Structure] A light-emitting device 1 mounted on a substrate 5, an optical fiber 4, and an optical system that integrally guides the light emitted from the light-emitting device 1 to one end face of the optical fiber 4 and converges the light-emitting device. In the element module, the optical axis of the emitted light of the light emitting element 1 is configured so as not to coincide with the optical center axis of the first optical component 2 closest to the light emitting element 1 among the optical components forming the optical system. There is. Here, "not coincident" means that both optical axes are parallel and offset from each other and both optical axes are not parallel to each other and are in a positional relationship such that they form a predetermined angle. Is included.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device module. More specifically, the present invention relates to a novel configuration of a light emitting element module configured by integrating a light emitting element with a lens, an isolator, an optical fiber and the like.

[0002]

2. Description of the Related Art FIG. 19 is a vertical longitudinal sectional view showing a typical structure of a light emitting device module.

As shown in FIG. 1, a light emitting element module is constructed by integrating a light emitting element 1, an optical system and an optical fiber 4. The light emitting element 1 is mounted on the substrate 5 together with the monitor photodiode 8 and the first lens 2. Here, the light emitting element 1 is mounted on the substrate 5 via the chip carrier 7, and the first lens 2 is mounted on the substrate 5 via the lens holder. Further, the substrate 5 is fixed to the bottom surface of the package 6 via a temperature control element such as a Peltier effect element.

On the other hand, a window sealed with hermetic glass 9 is formed on one side surface of the package 1, and an isolator 10 and a lens holder 11 are sequentially mounted on the outside of this window. The lens holder 11 supports the second lens 3, and the ferrule holder 12 is fixed to the other end of the lens holder 11. The ferrule 13 holding the end of the optical fiber 4 is inserted into the ferrule holder 12.

In the light emitting element module configured as described above, the emitted light emitted from the light emitting element 1 is
After passing through the lens 2, the isolator 10, the second lens 3 and the like in order, they are finally coupled to the end face of the optical fiber 4. Here, normally, the first lens 2 has a function of converting the emitted light of the light emitting element 1 into parallel light, and the second lens 3 converts the parallel light emitted from the first lens 2 into an optical fiber 4. Has a function of converging on the incident end face of.

As shown in FIG. 20, the functions of the first lens 2 and the second lens 3 are integrated into one optical component, and the physical structure is such that the mounting of the second lens is omitted. There is also an optical module.

[0007]

In the light emitting element module having the above-described structure, reflection is inevitably generated on the incident surface and the emission surface of the optical elements such as the first lens 2, the isolator 10, the second lens 3 and the like.

On the other hand, in a semiconductor light emitting element such as a light emitting diode or a semiconductor laser, if the above-mentioned reflected light returns during operation and is re-injected, the emission wavelength and output are unstable due to the effect of multiple reflection. Therefore, there is a problem that return light noise and distortion increase.

The isolator 10 used in the light emitting device module shown in FIG. 19 or 20 is provided for the purpose of blocking this kind of reflected light, and for reducing the end face reflection of the optical fiber. In addition, a contrivance such as obliquely polishing the end face of the optical fiber has been proposed and has already been implemented. However, this kind of device has no effect on the reflection generated on the surface of the first lens 2 mounted inside the module package.

Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art in the light emitting element module and to provide a novel structure capable of further suppressing the returning light in each optical component constituting the module. I am trying.

[0011]

According to the present invention, a light emitting device mounted on a substrate, an optical fiber, and an optical system for guiding and converging emitted light of the light emitting device to one end face of the optical fiber. In a light-emitting element module integrally configured with a light-emitting element, the optical axis of the emitted light of the light-emitting element is the optical center axis of the first optical component closest to the light-emitting element among the optical components forming the optical system. There is provided a light emitting device module, which is configured so as not to match with.

[0012]

The main feature of the light emitting device module according to the present invention is that the optical axis of the emitted light of the light emitting device and the optical center of the optical component through which the emitted light first passes do not coincide. There are features.

That is, in the conventional light emitting element module, each component is positioned so that the optical centers of the respective components are aligned on a straight line, mainly from the viewpoint of increasing the coupling efficiency. However, when the light emitted from the light emitting element passes through the optical components, reflected light that returns to the light emitting element is inevitably generated upon entering and exiting each optical component, which causes deterioration of the characteristics of the light emitting element. It was

On the other hand, in the light emitting element module according to the present invention, the optical axis of the optical component arranged immediately after the light emitting element is constructed so as not to coincide with the optical axis of the emitted light of the light emitting element. . The meaning of "not coincident" means that the two optical axes are parallel to each other and are offset from each other, and that the two optical axes are not parallel to each other and have a predetermined angle. Both are included.

With such a layout, since the optical axes of the reflected light on the incident surface and the output surface of the optical component inside the package deviate from the light emitting portion of the light emitting element, the return light returning to the light emitting portion of the light emitting element becomes small. . There is no loss caused by the deviation of the central axis of the emitted light from the central axis of the lens, but this loss does not become a substantial problem as will be described later.

In the light emitting device module according to the present invention having the above-described structure, the light emitting device and the optical component are not physically aligned with each other. Further, when the invention of the present application is realized by the angle shift, the mounting angle of the light emitting element or the optical component also changes. Therefore, the following configurations are preferable in order to facilitate the positioning of each component during manufacturing.

That is, in the light emitting element module, the substrate that supports the electronic components such as the light emitting element includes a horizontal portion on which the electronic components such as the light emitting element are mounted and a vertical portion that supports the optical components such as the lens as a whole. It has a V-shaped cross section. Here, by tilting the side surface of the vertical portion of the substrate at an appropriate angle and forming a groove, a step, etc. for guiding the chip carrier having the light emitting element mounted on the horizontal portion of the substrate, a special position can be obtained. , Or positioning at a special angle becomes easy. With such a method, the light emitting device module according to the present invention can be manufactured without lowering the productivity.

Hereinafter, the present invention will be described more specifically with reference to the drawings, but the following disclosure is merely an example of the present invention.
The technical scope of the present invention is not limited in any way.

[0019]

【Example】

[Embodiment 1] FIG. 1 is a horizontal vertical cross-sectional view showing a specific configuration example of a light emitting element module in which the present invention is realized by a method of offsetting a radiation optical axis of a light emitting element and an optical axis of an optical system. It should be noted that this light emitting element module is configured by the same constituent elements as the conventional light emitting element module shown in FIG. 11, and each constituent element is given a common reference numeral.
The peculiar feature of this light emitting element module is the arrangement and posture of each element as described later.

In this light emitting element module, the center axis of the emitted light of the light emitting element 1 is offset from the propagation optical axis of the optical system including the first lens 2, the optical isolator 10, the second lens 3 and the optical fiber 4. Are positioned so that

FIG. 2 is a diagram showing an extracted positional relationship between the light emitting element and the lens in the light emitting element module shown in FIG.

As shown in the figure, in this light emitting element module, the light emitting element 1 is arranged such that the light emitting portions thereof are spaced apart from the central axis of the lens 2 by a distance D. However, here, the optical axis of the light emitted from the light emitting element 1 and the central axis of the lens 2 are parallel to each other.

FIG. 3 is a graph showing the relationship between the offset amount of the light emitting element and the returned light amount in the arrangement shown in FIG. As shown in the figure, the returning light amount decreases as the offset amount increases.

On the other hand, FIG. 4 is a graph showing the relationship between the offset amount of the light emitting element 1 and the change in the relative light amount emitted from the lens 2.

As shown in the figure, the change in the relative light amount due to the offset is very small compared to the change in the returning light amount. Therefore, the decrease in the relative light amount can be neglected in consideration of the fact that the operation of the light emitting element is stable and the practically usable optical power increases due to the reduction of the returning light amount.

In the light emitting element module shown in FIG. 1, the monitor photodiode 8 behind the light emitting element 1 is also mounted so that its light receiving surface is inclined with respect to the monitor light. Return light due to reflection on the light receiving surface is also prevented.

[Embodiment 2] FIG. 5 is a view showing another embodiment of the light emitting device module according to the present invention. Note that, in FIG. 5, common reference numerals are given to constituent elements common to FIG.

As shown in the figure, this light emitting element module basically has the same structure as the light emitting element module shown in FIG. The feature of this light emitting element module is that the chip carrier 7 on which the light emitting element 1 is mounted is mounted so as to be inclined with respect to the vertical portion of the substrate 5 so that the emission optical axis of the light emitting element 1 is the propagation optical axis of the optical system. It is arranged to intersect with.

FIG. 6 is a diagram for explaining the relative position of the light emitting element and the lens and the action thereof in the light emitting element module according to the present invention.

As shown in the figure, in the light emitting element module according to the present invention, the center of the emitted light of the light emitting element 1
The lens 2 is arranged so as to form a predetermined angle δ with the central axis of the lens 2. Incidentally, such an arrangement can be actually realized by rotating either one or both of the light emitting element 1 and the lens 2.

FIG. 7 is a graph showing the relationship between the tilt angle of the light emitting element and the amount of returned light in the arrangement shown in FIG. From the figure, it can be seen that the amount of returning light decreases as the tilt angle increases.

On the other hand, FIG. 8 shows the displacement angle of the light emitting element 1,
6 is a graph showing a relationship with a change in relative light amount emitted from the lens 2.

As shown in the figure, the change in the relative light amount due to the angle shift is very small as compared with the change in the returning light amount. Therefore, the decrease in the relative light amount can be neglected in consideration of the fact that the operation of the light emitting element is stable and the practically usable optical power increases due to the reduction of the returning light amount.

[Embodiment 3] FIG. 9 is a diagram showing an example in which the light emitting device module according to the present invention shown in FIG. 5 is modified into a structure that is easier to manufacture. Here, common reference numerals are given to constituent elements common to FIG.

That is, in this light emitting element module, the surface of the vertical portion 5a of the substrate 5 on the light emitting element 1 side is formed to be inclined. Therefore, when the chip carrier 7 loaded with the light emitting element 1 is mounted on the substrate, the chip carrier 7 can be extremely easily positioned by pressing it against the inclined vertical portion 5a. Therefore, the structure shown in FIG. 5 can be realized with good reproducibility only by using the substrate 5 having a predetermined shape.

Similar to FIG. 9, FIG. 10 is a modified example of the light emitting device module shown in FIG. 5, in which the outer surface of the vertical portion 5a of the substrate 5 is tilted to support the first lens 3. The holder is tilted. With such a shape of the substrate 5, as a result, the same function as that of the light emitting element module shown in FIG. 5 is realized.

In each of the above embodiments, the first and second
Although the light emitting element module including the pair of lenses has been described as an example, it goes without saying that these configurations are also effective for the single lens type light emitting element module shown in FIG.

[Embodiment 4] FIG. 11 shows another modification of the light emitting element module shown in FIG. 5, and common constituent elements are designated by the same reference numerals as those in FIG. Further, in this figure, only the substrate 5 and the members loaded therein are shown.

In this light emitting device module, the shape of the vertical portion 5a of the substrate 5 is the same as that shown in FIG. On the other hand, in the horizontal portion 5b of the substrate 5, as shown in FIG.
As shown in (b), the groove 5c is cut. This groove 5c
Has substantially the same width as the chip carrier 7,
Moreover, it is formed to be inclined at a predetermined angle with respect to the outer edge of the horizontal portion 5c. Therefore, by loading so that the bottom of the chip carrier 7 fits in this groove, the chip carrier 7 can be loaded in a state in which it is tilted at a predetermined angle, as shown in FIG. 11 (a).

[Embodiment 5] FIG. 12 shows a further modification of the light emitting device module shown in FIG. 5, and the constituent elements common to those in FIG. 5 are designated by common reference numerals. Also in this figure, only the substrate 50 and the members loaded therein are shown.

The substrate 50 shown in FIGS. 12 (a) and 12 (b) basically has the same shape as the substrate 5 used in the conventional light emitting device module shown in FIG. 19 or FIG. . However, at the rear end of the substrate 50, as shown in FIG. 12 (b), a step for positioning a ceramic wiring substrate 51 described later is formed.

That is, in this light emitting device module, the substrate
After loading the ceramic wiring substrate 51 on the chip 50, the chip carrier 7 on which the light emitting element 1 is mounted is further mounted.
Here, the front end of the ceramic wiring board 51 is obliquely cut as shown in FIG. 12 (a). Therefore, the length of the ceramic wiring board 51 is different between the left and the right. The chip carrier 7 is positioned so as to be pressed against the oblique front end of the ceramic wiring board 51, and is arranged obliquely with respect to the board vertical portion 50a on which the lens holder is mounted.

With the above structure, substantially the same function as that of the light emitting device module shown in FIG. 5 is realized. In this configuration, if only the ceramic wiring board 51 is processed, the remaining manufacturing steps are completely the same as those of a general light emitting element module, which is advantageous from the viewpoint of productivity.

13 to 15 show a modification of the light emitting device module shown in FIG. 12, and the same components as those in FIG. 12 have the same reference numerals. Also in this figure, the substrate
Only 50 and the components loaded into it are shown.

The substrate 50 shown in FIG. 13 uses a ceramic wiring substrate 51 having the same shape as that shown in FIG. 12,
The chip carrier 7 is positioned by a step formed near the vertical portion 50a of the substrate 50. In the light emitting element module having such a configuration, the positioning can be easily performed only by bringing the chip carrier into contact with the step.

The board 50 shown in FIG. 14 also uses the ceramic wiring board 51 having the same shape as that shown in FIG. 12, but the vertical portion 50a of the board 50 is formed in the same manner as in the embodiment shown in FIG. The chip carrier 7 is positioned by having an inclined shape. With such a configuration, since the lens is mounted vertically to the lens bonding surface of the chip carrier, the accuracy of the jig used for fixing the lens is easy to obtain, and the manufacturing of the light emitting element module is facilitated.

The substrate 50 shown in FIG. 15 is a substrate having the same shape as that of the conventional light emitting element module, a ceramic wiring substrate.
51 is used, and the structure of the present invention is realized by inclining the outer surface of the vertical portion 50a of the substrate 50. With such a configuration, since the angle of the optical axis of the light emitting element can be defined by simple processing of the chip carrier, the light emitting element module can be manufactured at low cost.

The structure of each embodiment shown in FIGS. 11 to 15 can be applied to both the two-lens type light emitting element module shown in FIG. 19 and the single lens type light emitting element module shown in FIG. Of course, it can be applied to both.

[Sixth Embodiment] FIG. 16 is a diagram for explaining a technique known in the prior art for reducing the return light generated by the reflection on the end face of an optical fiber.

That is, the end face reflection of the optical fiber cannot be ignored as one of the causes of the returning light to the light emitting element in the light emitting element module. Therefore, in the past, FIG.
As shown in (a), the end face of the optical fiber is obliquely polished to prevent the end face of the optical fiber and the light emitting element from facing each other. However, if the end face of the optical fiber is slanted, the optical axis of the coupled light to the optical fiber will form a predetermined angle with the propagation optical axis of the optical fiber according to Snell's law. Moreover, the coupling efficiency with respect to the optical fiber is reduced. Therefore, conventionally, as shown in Fig. 16 (b), the angle of the incident light with respect to the optical fiber can be adjusted by inclining the optical fiber or by injecting the light obliquely from the direction away from the propagation optical axis of the optical fiber. To improve the coupling efficiency.

FIG. 17 is a schematic diagram showing the structure of an optical system of a light emitting element module in the case where the technique for reducing the end facet reflection of an optical fiber as described above is combined with the structure according to the present invention shown in FIGS. 1 and 2. FIG.

As shown in the figure, the optical axes of the light emitting element 1, the first lens 2, the second lens 3 and the optical fiber 4 are sequentially offset and arranged so that the light emitted from the light emitting element 1 is emitted from the optical fiber. The light entering 4 becomes at a predetermined angle with respect to the propagation optical axis of the optical fiber.

FIG. 18 is a diagram schematically showing the structure of the optical system of the light emitting element module when the above-mentioned technique is combined with the structure according to the present invention shown in FIGS. 5 and 6.

When the arrangement of the present invention shown in FIGS. 5 and 6 is applied to the structure of an optical system composed of an optical fiber, a lens and a light emitting element as shown in FIG. 18, as shown in FIG.
The optical axes of the first lens 2, the second lens 3 and the optical fiber 4 are sequentially offset and arranged, and the light emitting element 1 is installed so as to be inclined so that the light is emitted from the light emitting element 1 and enters the optical fiber 4. The light comes to form a predetermined angle with respect to the propagation optical axis of the optical fiber.

With the above-described structure, it is possible to reduce the return light due to the reflection on the end face of the optical fiber, and at the same time, to improve the coupling efficiency of the light to the optical fiber whose end face is inclined. In the entire module, it is possible to reduce both the return light and improve the coupling efficiency with a simple configuration.

Further, as described above, a layout has been known in which the angle of the incident optical axis is shifted with respect to the propagation optical axis of the optical fiber in order to improve the coupling efficiency with respect to the optical fiber whose end face is inclined. According to a preferred aspect of the present invention, when the emission optical axis of the light emitting element is further shifted from the optical axis of the optical system arranged on the incident optical axis, the deviation of the emission optical axis from the propagation optical axis of the optical fiber becomes small. By offsetting the arrangement of the light emitting elements to the side, it is possible to reduce the offset amount between the optical fiber and the light emitting element in the entire light emitting element module.

[0057]

As described in detail above, according to the present invention, it is possible to effectively reduce the amount of light returning from each optical component in the light emitting element module to the light emitting element, so that the operation of the light emitting element is stabilized. Therefore, the characteristics of the entire light emitting element module can be improved.

Further, the light emitting element module according to the present invention is basically realized by using the same members as the conventional light emitting element module and only by changing the layout. Therefore, it can be realized without increasing the manufacturing cost and the manufacturing man-hour.

[Brief description of drawings]

FIG. 1 is a horizontal cross-sectional view showing a basic configuration of a light emitting device module according to the present invention.

FIG. 2 is a diagram for explaining a positional relationship between a light emitting element and a lens in the light emitting element module shown in FIG.

3 is a graph showing the relationship between the offset amount of the light emitting element and the amount of light returned to the light emitting element in the light emitting element module shown in FIG.

FIG. 4 is a graph showing a relationship between an offset amount of a light emitting element and a relative light amount emitted from a lens in the light emitting element module shown in FIG.

FIG. 5 is a horizontal vertical cross-sectional view showing another basic configuration of the light emitting device module according to the present invention.

6 is a diagram for explaining the positional relationship between a light emitting element and a lens in the light emitting element module shown in FIG.

7 is a graph showing the relationship between the tilt angle of the light emitting element and the amount of light returning to the light emitting element in the light emitting element module shown in FIG.

8 is a graph showing the relationship between the tilt angle of the light emitting element and the relative amount of light emitted from the lens in the light emitting element module shown in FIG.

9 is a diagram showing a modification of the light emitting element module shown in FIG.

10 is a diagram showing another modification of the light emitting device module shown in FIG.

11 is a diagram showing another modification of the substrate that can be used in the light emitting device module shown in FIG.

12 is a diagram showing another modification of the substrate that can be used in the light emitting device module shown in FIG.

13 is a diagram showing another modification of the substrate that can be used in the light emitting device module shown in FIG.

14 is a diagram showing another modification of the substrate that can be used in the light emitting device module shown in FIG.

15 is a diagram showing another modification of the substrate that can be used in the light emitting device module shown in FIG.

FIG. 16 is a diagram for explaining a conventionally known technique for reducing return light generated by reflection on the end face of an optical fiber.

17 is a diagram schematically showing a basic configuration when the technique shown in FIG. 16 is applied to the light emitting device module according to the present invention shown in FIG.

18 is a diagram schematically showing a basic configuration when the technique shown in FIG. 16 is applied to the light emitting device module according to the present invention shown in FIG.

FIG. 19 is a vertical vertical sectional view showing a typical configuration of a conventional light emitting device module.

FIG. 20 is a vertical longitudinal sectional view showing another typical configuration of a conventional light emitting device module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light emitting element, 2 ... 1st lens, 3 ... 2nd lens, 4 ... Optical fiber, 5, 50 ... Substrate, 6 ... Package, 7 ... Chip carrier , 8 ... Photodiode for monitor, 9 ... Hermetic glass, 10 ... Isolator, 11 ... Lens holder, 12 ... Ferrule holder, 13 ... Ferrule

Claims (10)

[Claims] 1. A light emitting device comprising a light emitting device mounted on a substrate, an optical fiber, and an optical system for guiding and converging the emitted light of the light emitting device to one end face of the optical fiber. In the module, the optical axis of the emitted light of the light emitting element is configured so as not to coincide with the optical center axis of the first optical component closest to the light emitting element among the optical components forming the optical system. A light emitting device module characterized by the above. 2. The light emitting element module according to claim 1, wherein the optical axis of the emitted light of the light emitting element is parallel to the optical center axis of the first optical component. module. 3. The light emitting element module according to claim 1, wherein an optical axis of emitted light of the light emitting element and an optical axis of the first optical component are not parallel to each other, and light emission of the light emitting element. A light-emitting element module, which is characterized by intersecting at a position other than the center. 4. The light emitting element module according to claim 3, wherein the substrate includes a horizontal portion supporting the light emitting element and a vertical portion supporting the first optical component.
At least one surface of the vertical portion has a predetermined angle which is not a right angle with respect to the optical axis of the emitted light of the light emitting element. 5. The light emitting device module according to claim 3, wherein the light emitting device is mounted on the substrate via a chip carrier, and a step for guiding the chip carrier is provided on the substrate. A light emitting element module, which is formed. 6. The light emitting device module according to claim 5, wherein the step is formed by a trapezoidal small substrate loaded on a horizontal portion of the substrate. 7. The light emitting element module according to claim 1, wherein the optical isolator included in the optical system is a surface perpendicular to the optical axis of the emitted light of the light emitting element. The light emitting element module is mounted so as to form a predetermined angle of less than 90 degrees with respect to. 8. The light emitting element module according to claim 1, wherein the incident end face of the optical fiber is not perpendicular to the propagation optical axis of the optical fiber. A light-emitting element module that is molded. 9. The light emitting element module according to claim 8, wherein the optical system comprises: a first optical component that collimates light emitted from the light emitting element into parallel light; and an end surface of the optical fiber. And a second optical component for converging the emitted light, the emission optical axis of the light emitting element is parallel to the optical center axis of the first optical component, and the end face of the optical fiber is of the optical fiber. The light emitting portion of the light emitting element is disposed so as to deviate from the optical center axis of the first optical component on the side where the angle formed with respect to the propagation optical axis is an obtuse angle, and the light is emitted from the optical system. The incident angle of the light injected into the end face of the fiber is an optimum incident angle obtained according to Snell's law based on the angle formed by the end face of the optical fiber with respect to the propagation optical axis of the optical fiber. Light emitting element module. 10. The light emitting element module according to claim 8, wherein the optical system comprises: a first optical component that collimates light emitted from the light emitting element into parallel light; and an end surface of the optical fiber. And a second optical component for converging the emitted light, wherein the emission optical axis of the light emitting element forms a predetermined angle of less than 90 degrees with respect to the optical center axis of the first optical component, The emission optical axis of the light emitting element is arranged so that the end face of the optical fiber is at an acute angle to the propagation optical axis of the optical fiber, and the emission optical axis of the light emitting element deviates from the optical center axis of the first optical component. And the incident angle of the light injected from the optical system to the end face of the optical fiber is determined according to Snell's law based on the angle formed by the end face of the optical fiber with respect to the propagation optical axis of the optical fiber. Luminescent element characterized by an optimum incident angle Module.