JPH0651168A - Light signal transmission device - Google Patents

Abstract

PURPOSE:To inexpensively build an optical parallel transmission module advantageous for transmission of image information in and out of image processing equipment. CONSTITUTION:This optical signal transmission device is constituted to transmit light signals by coupling a solid-state light emitting element array disposed with plural pieces of solid-state light emitting elements 1 which emit light from the end faces in accordance with energization in an array form and a holding member holding the optical fiber array disposed with plural pieces of the optical fibers 2 in an array form and optically coupling the respective exit light rays of the respective solid-state light emitting elements 1 to the respective optical fibers 2. The above-mentioned solid-state light emitting element array is constituted by forming an LED array and optical fiber array as a multimode type optical fiber sheet. The respective light output ends of the respective solid-state light emitting elements 1 are provided with reflection members 4 for reflecting the exit light rays thereof and introducing these light rays to the corresponded optical fibers 2. The light transmission which assures the necessary signal band of several tens MHz and the transmission distance of several hundreds m in and out of the image processing equipment is attained at a low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical signal transmission device for transmitting a signal using a plurality of solid state light emitting elements and an optical fiber array when transmitting digital data at high speed between devices or inside a device.

[0002]

2. Description of the Related Art In recent image processing equipment and the like, image data is used inside and outside the equipment as a digital value having a gradation (1 pixel data corresponds to a plurality of bits, for example, 8 bits). . Then, it is necessary to transmit these digital data inside and outside the device.
In particular, multiple bit data are often transmitted, and parallel data can be transmitted as it is at a relatively high speed (several MHz) rather than using a high-speed optical transmission device that performs parallel-to-serial conversion of signals and then transmits. It can be said that the transmission is advantageous in terms of radiated noise, because the parallel-serial and serial-parallel conversion circuits are not required, and the maximum data rate in the system is low.

From such a point of view, JP-A-2-2898
According to Japanese Patent Laid-Open No. 03, a parallel transmission optical module is proposed in which a plurality of signals are transmitted using a solid state light emitting element array and an optical fiber array. In particular, according to the above-mentioned publication, regarding the coupling between the solid-state light-emitting element and the optical fiber array, a light beam is directly incident on the fiber end face, or an imaging element (lens) is interposed between the optical fiber and the solid-state light-emitting element. I am trying.

[0004]

However, when a semiconductor laser (LD) is used for the solid-state light emitting device, the light flux emitted from the LD is narrow, the coupling efficiency with the optical fiber is good, and high-speed transmission (about several GHz) is supported. Possible, but costly. Moreover, when a single mode optical fiber is used as the optical fiber array used, high speed transmission (several GH
However, since the diameter of the optical transmission part (core) of the optical fiber is several μ, highly accurate alignment is required and the manufacturing cost becomes high.

[0005]

According to a first aspect of the present invention, a solid-state light-emitting element array in which a plurality of solid-state light-emitting elements that emit light from an end face when energized are arranged in a row, and a plurality of optical fibers are arranged in a row. In an optical signal transmission device configured to couple a holding member that holds the optical fiber array arranged in a shape, optically couple each emitted light of each solid state light emitting element to each optical fiber, and transmit an optical signal. The solid-state light-emitting element array was an LED array, the optical fiber array was a multi-mode optical fiber sheet, and a reflection member for reflecting the emitted light and guiding it to the corresponding optical fiber was provided at each light output end of each solid-state light-emitting element.

In this case, according to the second aspect of the present invention, the diameter of each light output end face of each solid state light emitting element is made smaller than the diameter of the optical waveguide portion of each optical fiber, and each solid state light emitting element side of each light output end is formed. Solid-state light-emitting element array and optical-fiber array with reflecting members in which conical-shaped reflecting holes that spread concentrically so that the diameter on the side of each optical fiber is larger than the diameter of And fixed together.

In the invention described in claim 3, instead of the reflection hole described in claim 2, the solid-state light emitting element is expanded so that the width on each optical fiber side is larger than the width on each optical output end side. It was a pyramidal reflection hole.

According to the invention described in claim 4, instead of such a reflection hole, there is provided a reflection groove which expands so that the width of each optical fiber side is larger than the width of each light output end side of each solid state light emitting element. did.

In the invention according to claim 5, the material of these reflecting members is a material that can be etched.

In addition, according to the invention described in claim 6, a pair of positioning portions are formed on the holding member for fixing and holding the optical fiber array and the reflecting member so as to be coupled to each other for positioning.

Further, in the invention according to the seventh aspect, the holding member for fixing and holding the optical fiber array and the reflecting member,
A pair of positioning portions that are coupled to each other for positioning are formed, the light emitting portion of the solid state light emitting element array is positioned inside the reflection groove, and the solid state light emitting element is positioned and fixed on the reflecting member.

[0012]

According to the first aspect of the invention, the edge-emitting type L
Since the ED array and the multimode optical fiber sheet are coupled by the reflecting member, the optical transmission that secures a signal band of tens of MHz and a transmission distance of hundreds of meters required inside and outside the image processing device is low. Realized at a price.

In this case, according to the second to fourth aspects of the present invention, since the reflection member having the reflection hole or the reflection groove which is expanded from the solid-state light emitting element side to the optical fiber side is used, it is coupled to the optical fiber. Efficiency is improved. In particular, a conical or quadrangular pyramid-shaped reflection hole or a spread-shaped reflection groove makes it easy to manufacture a reflection member having a simple shape and uses only plane reflection. Therefore, it is not necessary to make the focal length and the optical axis accuracy severe. In addition, when the reflection groove is used, it can be easily manufactured on a flat substrate, and connection with an optical fiber or a solid-state light emitting element is easy.

Further, according to the invention of claim 5, since the material of the reflecting member is an etchable material,
The reflecting member can be manufactured by using a semiconductor manufacturing process, and highly accurate reflecting members can be mass-produced to reduce the cost. In particular, among the materials that can be etched, if the same material as that of the solid-state light-emitting element side is used, there is almost no difference in thermal expansion between the two, so that relative displacement between the solid-state light-emitting element and the reflecting member is prevented.

Further, in the invention according to claim 6,
Since the holding member for the optical fiber array and the reflecting member are formed of a pair of positioning pins and positioning holes, and a pair of positioning portions that are coupled to each other are formed, assembly with high positional accuracy can be easily ensured.

According to the present invention, the solid-state light emitting element array is fixed on the reflecting member, and the optical fiber array is positioned and fixed on the reflecting member using the positioning portion. The optical module based on the member can be easily integrated.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. In this embodiment, a GI type (multimode type) optical fiber sheet is used as the optical fiber array to satisfy the required data transfer rate inside and outside the image processing apparatus (tens of M).
It is possible to transmit a signal of several hundred meters in Hz), and an edge emitting solid-state light emitting element array that can be used in this band, specifically L
Basically, a low-cost optical signal transmission device is configured by using the ED array.

Here, when the edge emitting LED array and the GI optical fiber array are used, the emission pattern of the LED array is wide (close to perfect diffusion) in the array direction (direction parallel to the substrate) and vertical. Since it is narrow in the direction (direction perpendicular to the substrate) (close to the emission pattern of the LD), the coupling efficiency with the optical fiber is lower than that of the LD.

In consideration of such a point, in this embodiment, in addition to the above-mentioned basic structure, the light flux in the array direction of the light from each LED of the edge-emitting LED array is provided with an array-shaped reflecting member. By utilizing this, the optical fibers are efficiently coupled to each optical fiber of the optical fiber array to perform optical transmission.

FIG. 1 shows a conceptual basic structure of the solid-state light-emitting element array of the edge-emitting type (LED structure) 1 and a corresponding optical fiber 2 in the GI-type optical fiber array. And a reflection member 4 having a reflection path 3 is integrally fixed and interposed between the two. Here, the optical fiber 2 is composed of a core (optical waveguide portion) 5 and a clad 6 surrounding the core 5, and the diameter of the core 5 is set to be larger than the diameter of the light output end face of the solid state light emitting device 1. Corresponding to such a difference in diameter, the reflection path 3 is viewed in the array direction,
The solid light emitting element 1 has a shape that expands toward the optical fiber 2 side.

In such a configuration, the light emitted from each solid-state light emitting element 1 is combined in a state where the light flux in the array direction is reflected in the reflection path 3 of the reflecting member 4 and the incident light flux to the optical fiber 2 is increased. Therefore, the coupling efficiency is increased. At this time, the luminous flux transmitted by the optical fiber 2 is equivalent to the N.V. Only the light flux of A or less, and a high reflection film may be formed on the reflection surface of the reflection path 3 in the reflection member 4, or the reflection member 4 itself may be formed of a material having a high reflectance. In particular, when using a material having a high reflectance, the shape of the reflection path 3 may be formed with high accuracy, and it is not necessary to form a reflection film.

By the way, in the example shown in FIG. 1, the light beam emitted from the solid-state light-emitting element 1 is incident on the reflecting surface of the reflecting path 3 at angles α ₂ and β ₂ and is equivalent to the optical fiber 2. A light beam incident at an angle of A (0.5: about 11.5 °) or less is transmitted. Incidentally, the incident angles α ₁ and β _{1 with} respect to the optical fiber 2 are α ₁ = 90 ° − (α ₂ + γ) <11.5 ° β ₁ = 90 ° − (, where γ is the spread angle of the reflection path 3. β ₂ + γ) <11.5 ° and α ₂ + γ> 78.5 ° β ₂ + γ> 78.5 °. Therefore, by providing the reflecting member 4, the N.V. equivalent to the optical fiber 2 is provided. A large number of light beams are incident at an angle of A or less, and the coupling efficiency is improved.

Here, a specific example of the reflection member 4 is illustrated in FIG. FIG. 1A shows a configuration in which the reflection holes 3a that expand into a conical shape are arranged in rows as the reflection paths 3. The same figure (b) shows the reflection hole 3b which spreads out in a quadrangular pyramid
The reflection paths 3 are arranged in a row. FIG. 3C shows a configuration in which the reflection grooves 3c having an expanded shape are arranged in rows as the reflection paths 3. With the conical reflection hole 3a, manufacturing is relatively easy. In the case of the quadrangular pyramidal reflection hole 3b, the light flux in the array direction can be efficiently guided to the optical fiber 2 side. In the case of the reflection groove 3c, the light flux is reflected by both surfaces (both walls) of the groove and guided to the optical fiber 2 side, but the planar shape is equivalent to the expanded quadrangular pyramid shape and is efficiently guided to the optical fiber 2.

In any case, if the material of the reflecting member 4 is an etchable material, it can be formed by a semiconductor manufacturing process, and the positions and shapes of the holes and the grooves 3a to 3c are highly accurate. can do. In particular, if the same material as the solid-state light-emitting element 1 is used, the expansion coefficient due to heat becomes close, and the relative positional accuracy with the solid-state light-emitting element array can be maintained.

GI with a large core diameter of about 50 μm
By using the mold optical fiber array, the relative position accuracy of the solid state light emitting element array, the reflecting member 4, and the optical fiber array may be about several μm, and if the accuracy of each component is controlled, the assembly becomes relatively easy. .

Particularly, when the optical fiber array 5 and the reflecting member 4 are assembled, as shown in FIG. 3 or 4, cylindrical holes 6 as positioning portions are formed with high precision on both sides of the reflecting member 4 in the array direction. On the other hand, a cylindrical pin 8 serving as a positioning portion corresponding to the cylindrical hole 6 is formed with high precision on both sides of the holding member 7 holding the optical fiber array 5 in the array direction, and the cylindrical pin 8 is formed into a cylindrical hole. If it is fitted and connected to 6,
Easy and highly integrated. The cylindrical hole 6 and the cylindrical pin 8 may be used only for positioning, and an adhesive may be used for integrally fixing them. Further, the cylindrical hole 6 and the cylindrical pin 8 are relative to each other, and the cylindrical pin 8 may be formed on the reflecting member 4 side and the cylindrical hole 6 may be formed on the holding member 7 side. . However, if the holding member 7 having the cylindrical pin 8 is used, a general MF connector can be used to connect the optical fiber arrays.

In order to integrate the reflecting member 4 and the solid state light emitting element array, it is preferable to fix the solid state light emitting element array substrate on the reflecting member 4. At this time, if the back surface of the solid state light emitting element array substrate is used as a reference, it can be fixed on the reflecting member 4. In this case, the parallelism between the back surface of the solid state light emitting element array substrate and the element surface determines the coupling efficiency.

Therefore, in the present embodiment, the reflection member 4 and the solid state light emitting element array are fixed with reference to the element surface 9a of the solid state light emitting element array substrate 9 as shown in FIG. Each solid-state light emitting element 1 is provided in each reflection groove 3c above.
Highly accurate assembly is possible by fixing the light emitting end surface 1a of the above (see FIG. 6) and fixing the substrate surface between each solid state light emitting element 1 and the upper surface of the wall forming the reflection groove 3c with an adhesive. Becomes

[0029]

According to the invention of claim 1, the solid-state light-emitting element array is an LED array, the optical fiber array is a multimode optical fiber sheet, and the emitted light is reflected at each light output end of each solid-state light-emitting element. Since a reflection member for guiding the corresponding optical fiber is provided, it is possible to realize optical transmission at a low price, which secures a required signal band of several tens of MHz and a transmission distance of several hundred meters inside and outside the image processing device. You can

In this case, according to the second to fourth aspects of the invention, since the reflection member having the reflection hole or the reflection groove having the shape expanded from the solid state light emitting element side to the optical fiber side is used, the optical fiber is used. It is possible to improve the coupling efficiency with respect to, and in particular, a conical or quadrangular pyramid-shaped reflection hole or a spread-shaped reflection groove has a simple shape and facilitates the manufacture of a reflection member, and also provides planar reflection. Only the lens is used, so it is not necessary to make the focal length and optical axis accuracy strict like a lens. In addition, when using a reflection groove, it can be easily manufactured on a flat substrate. In addition, it is possible to easily connect to an optical fiber or a solid-state light emitting element.

Further, according to the invention of claim 5, since the material of the reflecting member is an etchable material, the reflecting member can be manufactured by utilizing a semiconductor manufacturing process, and a highly accurate reflecting member can be obtained. It can be mass-produced to reduce the cost, and in particular, if the same material as the solid-state light-emitting element side is used among the materials that can be etched, there is almost no difference in thermal expansion between the two, so that the solid-state light-emitting element can be manufactured. -It is possible to prevent relative displacement between the reflecting members.

Further, according to the invention of claim 6, a pair of positioning portions which are made of a combination of a positioning pin and a positioning hole and are coupled to each other are formed in the holding member and the reflecting member for the optical fiber array. Therefore, assembly with high positional accuracy can be easily ensured.

According to the seventh aspect of the invention, the solid state light emitting element array is fixed on the reflecting member, and the optical fiber array is positioned and fixed on the reflecting member using the positioning portion. Therefore, it is possible to easily realize the integration of the optical module based on the reflecting member.

[Brief description of drawings]

FIG. 1 is a plan view of an essential part showing an embodiment of the present invention.

FIG. 2 is a perspective view showing several examples of the configuration of a reflecting member.

FIG. 3 is an exploded perspective view showing an example of coupling between the optical fiber array side and a reflecting member.

FIG. 4 is an exploded perspective view showing another example of the coupling between the optical fiber array side and the reflecting member.

FIG. 5 is a perspective view showing an example of making an optical module.

FIG. 6 is a perspective view showing a portion A in FIG. 5 in an enlarged manner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solid-state light emitting element 2 Optical fiber 2a Optical waveguide part 3a Conical reflection hole 3b Square pyramidal reflection hole 3c Reflection groove 4 Reflecting member 5 Optical fiber array 6 Positioning part 7 Holding member 8 Positioning part

Claims (7)

[Claims] 1. A holding device for holding a solid-state light-emitting element array in which a plurality of solid-state light-emitting elements that emit light from an end face when energized are arranged in a row, and an optical fiber array in which a plurality of optical fibers are arranged in a row. In the optical signal transmission device configured to couple a member and optically couple each emitted light of each solid state light emitting element to each optical fiber to transmit an optical signal, the solid state light emitting element array is an LED array, An optical signal transmission device characterized in that a fiber array is a multimode optical fiber sheet, and a reflection member for reflecting the emitted light and guiding it to a corresponding optical fiber is provided at each light output end of each solid state light emitting element. 2. The diameter of each light output end face of each solid state light emitting element is formed smaller than the diameter of the optical waveguide part of each optical fiber, and the diameter of each solid state light emitting element is closer to each optical fiber side than the diameter of each light output end side. The conical reflection holes that spread concentrically so that the size of the solid-state light-emitting element array and the optical fiber array are integrally fixed to each other. The optical signal transmission device according to claim 1, wherein 3. The diameter of each light output end face of each solid-state light-emitting element is formed smaller than the diameter of the optical waveguide portion of each optical fiber, and the width of each solid-state light-emitting element is closer to each optical fiber side than to each optical output end side. The reflection member having a quadrangular pyramid-shaped reflection hole that expands so as to increase the size is arranged in a row corresponding to each solid-state light-emitting device, and is integrally fixed between the solid-state light-emitting device array and the optical fiber array. The optical signal transmission device according to claim 1, wherein 4. The width of each light output end face of each solid-state light-emitting element is formed smaller than the diameter of the optical waveguide portion of each optical fiber, and the width of each solid-state light-emitting device is closer to each optical fiber than to each light output end. Characterized in that a reflection member having a reflection groove that expands so as to increase the size is arranged in a row corresponding to each solid state light emitting element is integrally fixed between the solid state light emitting element array and the optical fiber array. The optical signal transmission device according to claim 1. 5. The optical signal transmission device according to claim 2, 3 or 4, wherein the material of the reflecting member is a material that can be etched. 6. The optical signal transmission device according to claim 5, wherein a pair of positioning portions that are mutually coupled and positioned are formed on the holding member and the reflecting member that fix and hold the optical fiber array. 7. A pair of positioning portions, which are coupled to each other and are positioned, are formed on a holding member for fixing and holding the optical fiber array and a reflecting member, and the light emitting portion of the solid state light emitting element array is positioned inside the reflection groove. The optical signal transmission device according to claim 4, wherein the solid state light emitting element is positioned and fixed on the reflecting member.