JP2001141936A - Optical wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical wiring board that is high in reliability against external stress. SOLUTION: A holding part 10 for firmly retaining an optical fiber 11 is provided in a boundary between the body 12 of the optical wiring board and an optical fiber projection 13 protruding from the body 12; a stress imparted to the boundary is thereby dispersed and reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wiring board for optically connecting optical elements or optical circuits.

[0002]

2. Description of the Related Art Conventionally, in a board (optical board) on which an optical element is mounted, to connect optical elements on the optical board, a pigtail optical fiber coming out of one element is connected to the other element. It was connected by fusing with an optical fiber.

In the case of such fusion splicing, a considerably long extra length is required for setting the optical fiber in the fusion splicer outside the board, and this extra length must be accommodated in the board after the connection.

[0004] Alternatively, a method of connecting optical elements with a fiber with a connector using a pigtail with a connector is also used. Also in this case, the optical fiber needs an extra length, and a bundle of optical fibers appears.

[0005]

In order to solve such a problem relating to the extra length of the optical fiber, that is, the appearance of the bundle of optical fibers, an optical wiring board as disclosed in Japanese Patent No. 2574611 and the like has been proposed. There is. In addition, Japanese Patent Application Laid-Open No. H11-119034 discloses a technique related to automatic wiring of optical fibers.

However, in the conventional optical wiring board, very few proposals have been made to alleviate the stress at the portion where the optical fiber protrudes from the optical wiring board main body.
Although there is a proposal in which a base film as shown in 74611 is extended in a tab shape, the main purpose is to protect an optical fiber.
It is not intended to reduce the stress applied to the optical wiring board main body and the optical fiber protrusion.

As described above, in the conventional optical wiring board,
Since the fiber protruding from the wiring board does not have a structure to relieve stress, artificial stress load during or after the installation of the optical wiring board, or the fiber is installed in a bent state, and the fiber There is a danger that a temporary increase or a permanent increase in light loss may occur due to the load of the bending stress. In recent optical transmission systems, a method of transmitting a plurality of wavelengths to one fiber, separating the wavelengths for each wavelength, performing signal processing, and multiplexing again is going to be used.

[0008] In such an optical system, the optical wiring in the optical board and the optical wiring between the boards connecting the optical boards are required.
The number of optical fibers used is large, and the optical fibers protruding from the optical wiring board main body need to be long.

In addition, wiring in an optical board requires wiring in a limited space between optical elements, and it is assumed that a fiber protruding during mounting may be bent. further,
In the inter-board wiring, it is assumed that an optical wiring board is installed outside the rack housing the optical board and the protruding optical fiber is routed outside the rack in order to connect the boards.

As described above, in the optical wiring board, various stresses may be applied to the protruding optical fiber, and it is important to provide a structure that ensures reliability.

However, in the conventional optical wiring board, there is no optical wiring board in which special measures are taken against external force applied to the optical fiber protruding from the optical wiring board.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical wiring board which is highly reliable against external stress.

[0013]

According to the present invention, one or more optical fibers are wired on a substrate, and both ends of the optical fiber are extended outside the substrate. An optical wiring board on which a protrusion is formed,
An optical wiring board is formed by providing a holding portion for holding the optical fiber over the substrate and the optical fiber projecting portion. Here, a fixing member for fixing the optical fiber wired on the substrate may be provided, and the fixing member may be joined to a holding portion or may be formed integrally with the holding portion.

[0014] The holding section may be provided at least above the substrate.

[0015] The holding portion may reduce one or both of the thickness and the width of the holding portion outside the substrate with respect to an increase in the distance from the substrate.

[0016] The holding portion may have a bending stress greater than that of the optical fiber.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Example] A first embodiment of the present invention will be described with reference to FIGS.

(Background) First, the background of the present invention will be described.

In the optical wiring board, a large number of optical fibers protrude from the wiring board main body and are connected to various other optical components or optical boards. When connected to an optical component on an optical board, the optical component is generally preferentially arranged on a limited optical board, and the optical wiring board is generally arranged in an empty space. For this reason, the optical wiring board is required to have flexibility, and in many cases, the optical fibers protruding from the wiring board and the wiring board main body are bent and mounted. In this case, a bending stress is applied to a boundary portion between the optical fiber and the optical wiring board body, that is, a root portion where the optical fiber protrudes from the substrate of the optical wiring board.

In an optical wiring board for connecting optical boards,
Since the optical wiring board is installed outside the frame that houses the optical board, there is a risk that an unexpected stress may be applied to the optical fiber protruding from the optical wiring unit body during the operation.

Further, when the length of the protruding fiber is long, the fiber bends due to the weight of the fiber and stress is applied. Also between the optical boards, stress concentrates on the root portion where the optical fiber protrudes from the optical wiring board. This is known because stress concentrates on portions having different elastic moduli.

Therefore, in this example, in order to prevent stress concentration due to such external stress, a boot portion as a holding portion for relaxing the stress is provided at the boundary between the optical fiber and the optical wiring board. Is provided.

(Specific Example) Next, a specific example of an optical wiring board having a boot portion will be described.

FIG. 1 shows an example of the configuration of an optical wiring board provided with a boot 10.

Each of the one or more optical fibers 11 is wired on a substrate 12 as a main body of an optical wiring board using a one-stroke technique.

In the optical wiring board having such a wiring structure, the optical fiber projecting portion 13 as a portion of the optical fiber 11 protruding from one end of the substrate 12 and the substrate 12 on which the optical fiber 11 is wired straddle both. And the optical fiber 11
A boot portion 10 is provided as a portion for relaxing bending stress.

The boot portion 10 has a role of fixing the optical fiber 11 to the substrate 12 in order to relieve the stress, and a role of relieving the stress against bending or sudden movement of the optical fiber 11. ing.

The end A indicates an input / output end, and the end B indicates an output end. As described above, the optical wiring board is provided with a large number of optical fibers 11, and the optical fibers 11 project from the substrate 12, which is the main body of the optical wiring board.

This optical wiring board has a structure in which an optical fiber 11 is fixed on a substrate 12 with an adhesive in an optical wiring board main body, and further, a film or a resin is provided on an upper portion of the bonded optical fiber 11. ing.

Therefore, the optical fiber 11 is relatively firmly fixed on the substrate 12 which is the main body of the optical wiring board, but the optical fiber 11 of the optical fiber protrusion 13 protruding from the substrate 12 is a free end. ing.

However, since the boot portion 10 is provided near the optical fiber projecting portion 13 of the projecting optical fiber 11, stress is applied to the projecting optical fiber 11, and the optical fiber projecting portion of the optical fiber 11 is exposed. Even when stress concentrates on the portion near the portion 13, the stress concentration can be avoided, and further, the optical fiber 11 does not break or the curvature becomes small, so that the optical loss does not increase.

(Production Example) Next, an example of producing an optical wiring board will be described.

Here, a method of manufacturing the optical wiring board shown in FIG. 1 by using a typical wiring pattern and an operation result thereof will be described. Note that the booting effect does not depend on the wiring pattern of the optical wiring board.

First, the lowermost substrate 12 is set in a wiring device for automatically wiring the optical fiber 11,
Are wired one by one.

The substrate 12 is made of a polyethylene terephthalate (PET) film or a polyimide film having a thickness of 50.
A 25 μm-applied rubber-based pressure-sensitive adhesive was used. The adhesive sheet was covered as a protective layer on the wired optical fiber 11.

Here, one end A of the input / output terminal is 72
The two optical fibers 11 are divided into two sets, and a further 12 of the sets are taped, and the taped optical fibers 11 are arranged at a narrow interval of 1 mm.

The other end B is taped in units of eight or four optical fibers 11. The length of the protruding optical fiber 11 is about 10 cm.

The boot section 10 is made by using an injection device to apply silicone rubber as a material to the optical fiber 11.
It is manufactured by precisely applying the taped portion to the vicinity of the boundary between the tape fiber (that is, the optical fiber protrusion 13) and the substrate 12. In this case, the substrate 12
After applying silicone rubber to the upper and lower surfaces of
Leave to cure day and night. The length of the boot 10 is 15 mm from the end of the substrate 12.

At the end B where the tape fibers are arranged at a certain interval, each tape is booted independently. On the other hand, at the end A, three tape fibers having a small interval are collectively booted.

Then, an MT connector is attached to the end of the optical wiring board booted in this way, light is input to the position of the end A of the optical loss measuring device, and light is detected at the position of the end B. Connect the parts and measure the light loss. In this case, the tape fiber is bent at 90 degrees with respect to the substrate 12, and the wavelength is 1.55.
The optical loss variation at μm, 1.31 μm is measured.

As a result of the measurement, the loss fluctuation was 0.01 dB or less at both wavelengths. This is considered to be because the curvature radius of the tape fiber and the substrate 12 became 15 mm or more due to the booting, and loss due to bending was prevented.

On the other hand, when the boot is not used, the increase in the loss due to the 90-degree bending is such that the radius of curvature between the tape fiber and the substrate 12 is about 8 mm, and about 0.3 dB at 1.55 μm.
It was about 0.03 dB at 1.31 μm.

As described above, the effect of preventing an increase in light loss due to bending stress due to the booting has been clarified.

In the present embodiment, an example is shown in which the taped optical fiber 11 is booted. However, a single optical fiber may be booted, and the same effect can be obtained in this case. .

(Modification) Next, a modification of the optical wiring board will be described with reference to FIGS.

FIGS. 2 and 3 show an example in which a large number of taped optical fibers 11 are booted only at the upper and lower portions to form a boot portion 10 and integrated with the structure of the optical wiring board. is there.

FIG. 2 is a top view, and FIG. 3 is a sectional view. Since the optical fiber 11 formed into a tape has a certain strength in the left-right direction, the reliability can be maintained even if the optical fiber 11 is booted only in the up-down direction.

Needless to say, if boots are formed in the left-right direction, the strength is further increased.

Although the description has been given of the optical fiber taped here, the present invention can be similarly applied to a single optical fiber.

[Second Example] Next, a second embodiment of the present invention will be described with reference to FIGS. The description of the same parts as those in the first example is omitted, and the same reference numerals are given.

In the first example described above, various stresses applied to the optical fiber 11 are reduced by the boot portion 10, but the optical fiber 11 protruding from the optical wiring board is described.
In many cases, a plurality of optical fibers 11 are usually bundled in a tape shape. In this case, the stress applied to the optical fiber 11 is larger than that of one optical fiber.

If the optical fiber 11 is suddenly stressed, for example, if the optical fiber 11 is artificially hooked, an extremely large stress is applied to the boot portion 10.

Therefore, in this embodiment, the boot portion 10 is fixed by simultaneously covering the boot portion 10 and the upper portion of the optical wiring portion with the same material or the like, or the substrate 1 which is the optical wiring board main body portion.
A fixing member is provided so as to be joined to a part of the second member.

By providing such a fixing member, the stress can be widely dispersed throughout the optical fiber 11 and the entire wiring board or at the boundary, so that the deformation caused by the stress applied to the optical fiber 11 can be prevented by the optical fiber 11 and the boot portion. 10, an optical fiber 11 that spreads over a substrate 12 and causes an increase in light loss
Deformation at the boundary between the main body and the optical wiring board.

(Specific Example) Next, a specific example of an optical wiring board having a fixing member will be described.

FIG. 4 shows a configuration example in which the fixing member and the boot portion are integrated. Reference numeral 20 denotes a protective material as a fixing member that covers the entire upper surface of the optical wiring board. Since the protective member 20 is filled around the optical fiber 11 and is integrally formed of the same material as the boot portion 10, the stress applied to the optical fiber 11 can be reduced in the entire optical wiring board.

FIG. 5 shows a configuration example in which a weir 21 as a fixing member is provided at an end of the optical wiring board, and this weir 21 and the boot 10 are joined. In this case, the boot portion 10 is disposed above, below, right and left of the optical fiber 11 and is provided so as to surround one optical fiber.

The end of the optical wiring board can be reinforced by the weir 21, and the influence of the external force applied to the optical fiber 11 can be suppressed, so that the stress applied to the boot 10 can be dispersed.

(Production Example) Next, an example of producing an optical wiring board will be described.

On the substrate 12, the same pattern of the optical fiber 11 as in the first example was wired in the same manner, the wired optical fiber 11 was covered with a silicone resin, and the high hardness silicone was placed on the edge of the substrate 12. A weir is made of resin.

For booting, the boot portion 10 is manufactured by applying portions of the optical fiber projecting portion 13, the substrate 12, and the weir 21 where the optical fiber 11 protrudes, using silicone rubber.

By forming the boot portion 10 integrally with the weir 21 in this manner, when a bending stress is applied to the optical fiber 11, the deformation of the optical wiring board due to the bending disperses the stress over a wide range, and Loss and deformation of the optical wiring board can be reduced.

(Modification) Next, a modification of the optical wiring board will be described.

Various methods are conceivable for disposing the boot portion 10.

In view of this, first, the optical wiring board is provided so as to be wrapped around the substrate 12 and the optical fiber protruding portion 13 from above the optical fiber 11.

With such a structure, an effect of dispersing stress can be obtained. However, in this case, since the device is manufactured from the upper portion, the manufacturing time is shortened, and the lower portion of the optical wiring board is flat without protrusions. become weak.

Therefore, the boot 10 is connected to the optical fiber 11.
The structure is such that it is provided over both the substrate 12 and the substrate 12 and is installed from both the upper and lower directions of the substrate 12.

By providing the boots 10 from both directions, the above-mentioned disadvantage of weakening the stress can be overcome. In this case, although it takes time to manufacture, it can cope with the stress from above and below the wiring board.

[Third Example] Next, a third embodiment of the present invention will be described with reference to FIGS. The description of the same parts as those in the above-described examples is omitted,
The same reference numerals are given.

The external stress applied to the optical fiber 11 causes
Although stress concentrates at the boundary between two materials having different elasticities between the optical fiber 11 and the substrate 12, means for reducing the stress may be provided.

Therefore, in this example, the thickness of the boot 10
This is an example of a case where one or both of the widths are formed so as to gradually decrease as the distance from the wired substrate 12 to the outside thereof increases.

In this case, the length of the boot portion 10 may be at least 5 mm from the edge of the substrate 12 with respect to the longitudinal direction of the optical fiber 11.

Further, the material constituting the boot portion 10 may have a higher elasticity than the optical fiber 11 used.

(Specific Example) Next, a specific example of an optical wiring board having a different boot shape will be described.

FIGS. 6 and 7 show examples in which the width and thickness of the boot portion 10 are gradually reduced. FIG. 6 shows the boot 1
FIG. 7 shows an example in which the width of 0 is tapered, and FIG. 7 shows an example in which the thickness is tapered.

As described above, the substrate 1 serving as the optical wiring board main body is
By gradually decreasing one or both of the width and the thickness as the distance from the optical fiber 2 increases, when a bending stress is applied to the optical fiber 11, the optical fiber can be bent in a state close to a circle. Thereby, the loss due to the curvature can be minimized.

(Production Example) Next, an example of producing an optical wiring board will be described.

The optical fiber 11 is wired on the substrate 12 in the same manner as in the first example, and the upper portion is covered with an adhesive sheet to produce an optical wiring board.

The booting is to apply a silicone resin from the substrate 12 in the direction of the tape fiber (that is, the optical fiber protrusion 13) using an injection device, and to reduce the application pressure applied to the resin as the distance from the substrate 12 increases. This reduces the amount of resin to be applied.

This coating operation is performed on the upper and lower surfaces of the substrate 12, respectively, and the upper and lower sides of the tape fiber are booted.

As a result, the thickness of the boot part 10 is
2 and the tip of the boot had different shapes. That is, the shape of the boot portion 10 on the substrate 12 is 2 m thick.
m and a width of 5 mm, and at the tip of the boot portion 10 having a length of 20 mm, the thickness was about 0.3 mm and the width was almost the same as that of the tape fiber.

The end of the booted tape fiber manufactured as described above is held, and even if it is bent by 90 degrees or more with respect to the surface of the substrate 12, the radius of curvature of the boot portion 10 is 15 degrees.
mm or more could be obtained.

As described above, the structure of the boot portion 10 is such that the one or both of the width and the thickness of the boot portion 10 decrease as the distance from the wiring board increases, so that the thickness and the thickness of the boot portion 10 can be reduced at the portion away from the substrate 12. The width can be reduced to have almost the same elasticity as that of the optical fiber 11. On the other hand, as the distance from the substrate 12 increases, the thickness and the width increase, and the elasticity of the boot portion 10 increases to withstand large stress. Can be made.

Further, it is also possible to spread a part of the boot portion 10 on the substrate 12 horizontally wide like a weir structure so as to disperse the stress.

Further, the length of the boot portion 10, that is, the length of the boot portion 10 extending in the longitudinal direction of the optical fiber 11 from the edge of the substrate 12, which is the wiring board main body, is determined when the bending stress acts on the optical fiber 11. Greatly affects the curvature of As is well known, the bending loss of the optical fiber 11 increases rapidly as the curvature decreases. In this case, by setting the length of the boot portion 10 to 5 mm or more, light loss when a bending stress is applied can be reduced.

The material used for the boot portion 10 is such that the elasticity of the actually used boot portion structure is as follows.
What is necessary is just to be larger than the optical fiber 11. This means that the boot portion 10 can be made very small with a material having a large elastic modulus, and conversely, even with a material having a smaller elastic modulus than the optical fiber 11, the boot portion 10 can be formed as a booting material by increasing the structure of the boot portion 10. It means that it can be used.

[0088]

As described above, according to the present invention,
A holding portion for holding the optical fiber is provided at the boundary between the optical wiring board main body and the optical fiber protrusion protruding from the main body, so that the bending and tensile stress applied to the boundary is dispersed and reduced. Therefore, the optical loss fluctuation and the shape change can be reduced, whereby an optical wiring board having a very high reliability can be realized with respect to the external stress on the optical fiber or the taped optical fiber protruding from the substrate. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of an optical wiring board according to a first embodiment of the present invention.

FIG. 2 is a top view showing a modification of the optical wiring board.

FIG. 3 is a sectional view of the optical wiring board of FIG. 2;

FIG. 4 is a perspective view showing a configuration in which an optical wiring board main body and a boot according to a second embodiment of the present invention are integrated.

FIG. 5 is a perspective view showing a configuration in which a weir of an optical wiring board main body and a boot are joined.

FIG. 6 is a top view showing a configuration in which a width of a boot portion according to a third embodiment of the present invention is tapered.

FIG. 7 is a cross-sectional view showing a configuration in which the thickness is tapered.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Boot part (holding part) 11 Optical fiber 12 Substrate 13 Projection part of optical fiber 20 Protective material (fixing member) 21 Weir (fixing member)

Claims (5)

[Claims] 1. An optical wiring in which one or a plurality of optical fibers are wired on a substrate and both ends of the optical fiber are extended outside the substrate, so that an optical fiber projecting portion is formed at an end of the substrate. An optical wiring board, comprising: a holding portion for holding the optical fiber over the substrate and the optical fiber protrusion. 2. A fixing member for fixing the optical fiber wired on the substrate, wherein the fixing member is joined to a holding part or formed integrally with the holding part. 2. The optical wiring board according to claim 1, wherein: 3. The optical wiring board according to claim 1, wherein the holding section is provided at least above the substrate. 4. The holding section, outside the substrate,
4. The optical wiring board according to claim 1, wherein one or both of the thickness and the width of the holding portion decrease as the distance from the substrate increases. 5. The optical system according to claim 1, wherein the holding section has a bending stress greater than that of the optical fiber.
The optical wiring board according to any one of the above.