JPH10339818A - Optical wiring component and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical wiring component and its manufacture capable of performing mass-producing and reducing a connection cost by shortening connection work while securing reliability and saving space by reducing the occupancy space of a wiring part. SOLUTION: In this optical wiring component for maintaining a wiring shape by fixing at least a part of plural coated optical fibers 11, thermocompression- bondable films 15 and 16 or films with an adhesive are used for fiber fixation. Then, the fibers are cut to a length corresponding to the route length of a wiring route, the end parts are aligned to have a position and an angle at a prescribed input/output terminal and fixed and thereafter, fixed ends re arranged at a prescribed position. Further, the fibers between the fixed end s are aligned and at least a part of the aligned fibers is fixed by the thermocompression bondable films or the films with the adhesive.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical wiring component for optically connecting various optical components and a method of manufacturing the same.

[0002]

2. Description of the Related Art With the opticalization of telecommunication networks, various optical components,
2. Description of the Related Art Optical connections for transmitting information between optical boards and various optical signal processing devices by optical signals are widely used. Conventionally, in this type of optical connection, a single-core or multi-core optical fiber having connectors at both ends is used, and the connection between the terminals is manually performed one by one.

[0003] Single-core optical fibers are widely used for connection between terminals having complicated wiring routes because of their high wiring flexibility. Especially in the case of optical connections with a large number of wires, in addition to the connection work between the terminals, work to bundle and fix them together to prevent entanglement or entanglement between wires with the same wiring route It is carried out. On the other hand, a multi-core optical fiber is a tape made by arranging a plurality of fibers, such as four, eight, and sixteen, in a line, and has a low wiring flexibility. Since there is an advantage that the connection can be performed collectively and the connection work time can be reduced, the wiring path is widely used for optical connection between terminals having a relatively simple wiring path.

[0004]

However, as described above, in the conventional method, the connection work is performed manually, and therefore, when manufacturing an optical mounting board having tens of optical components, the work involved in wiring is required. The greatest disadvantage is that the time is enormous, and the cost of the optical wiring work and, consequently, the product cost are greatly increased. In addition to these fundamental disadvantages, there are various problems, such as mistakes such as misconnection of connection terminals during wiring work, which tends to reduce the reliability of products, and the large space occupied by wiring parts, making it difficult to miniaturize equipment. Problems.

[0005] In addition, a tape fiber used for the purpose of shortening the connection work time has a structure that is hardly bent in the tape arranging direction, so that it is used for connection between input and output terminals at an arbitrary position on a plane. At present, it is not a drastic solution to shorten the versatile connection work.

[0006] Therefore, a problem in the optical wiring component is to realize a mass production and a reduction in the connection cost by shortening the connection work while securing the reliability, and at the same time, to save the space occupied by the wiring portion, thereby saving. An object of the present invention is to provide an optical wiring component capable of realizing a space and a method of manufacturing the same.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and an optical wiring component according to the present invention has a wiring shape by fixing at least a part of a plurality of optical fiber cores. In the maintained optical wiring component, a thermocompression bonding film or a film with an adhesive is used for fixing the fiber.

In the method for manufacturing an optical wiring component according to the present invention, the fiber is cut into a length corresponding to the length of the wiring path, and the ends are aligned at predetermined positions and angles at input / output ends. The wiring component is fixed by fixing the fixed end to a predetermined position, further aligning the fibers between the fixed ends, and fixing at least a part of the aligned fibers with a thermocompression-bondable film or a film with an adhesive. Is manufactured.

According to the present invention, an optical wiring board is manufactured by manufacturing in advance a wiring component in which only an optical fiber and a connector or an optical fiber are shaped into a wiring path shape, and arranging this on a support substrate or in a support substrate. It enables mass production and cost reduction.

[0010]

Embodiment 1 An example in which an optical wiring component (FIG. 1a) for 8-core batch connection having an S-shaped wiring path is manufactured will be described.

In manufacturing the optical wiring component of the present invention,
First, the eight optical fibers 11 drawn from the eight optical fiber bobbins 12 are closely aligned in parallel on the same plane, and fixed by the fixing jig 13. Next, the other end of the fiber array is fixed by a fixing jig 14 (FIG. 1B). At this time, the fixing jig 14 is attached at a position where the lengths of the eight fibers between the fixing jigs 13 and 14 are the same. This is because, in the S-shaped wiring path, the wiring path length of each fiber is the same. Next, the fixing jig 14 is cut on the fiber bobbin side. Next, the fixing jigs 13 and 14 are arranged in the same positional relationship as the optical wiring input / output end position of the optical wiring component (FIG. 1).
c).

At this time, since the bending stress of the eight fibers sandwiched between the jigs is applied, the fibers are rearranged so that the bending stress is minimized three-dimensionally, and when observed from a direction perpendicular to the fiber arrangement direction, FIG. As shown in the figure, some of the wiring paths overlap. When viewed from the vertical direction, FIG.
The fiber 11 is arranged with undulations relative to the fiber arrangement surface as indicated by d ′. The optical fiber portion of the fiber with the fixing jig in this state is connected to a pair of thermocompression bonding films 15 and 1.
By sandwiching the fiber from the vertical direction in the arrangement plane at 6, the eight fibers are automatically arranged and aligned on the same plane (FIG. 1).
a).

According to such an alignment method, the optical fiber is fixed only at both ends and the portion between the terminals can be freely bent. Therefore, in the in-plane direction, the optical fiber can be freely bent so as to minimize the stress due to the strain. It can be bent and arranged. As a result, a component with extremely small residual stress in the fiber portion can be realized.

Since the thermocompression bonding film does not have adhesiveness in a normal state, it does not hinder the rearrangement of the fiber when the fiber is sandwiched between the thermocompression bonding films. For this reason, it is particularly effective when the fibers need to be rearranged when sandwiched between films as in this embodiment.

Next, the thermocompression-bondable film is thermocompressed to fix the fiber portion. After this, remove the fixing jig,
The coating is removed from the end of the fiber array, the excess length of the fiber is processed by cleaving the end face, and the end face of the fiber is processed to complete the component.

Using the above manufacturing method, polychlorotrifluoroethylene (PCTF)
E), polyvinylidene chloride (PVdCl), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyethylene terephthalate (PE)
T), ethylene-tetrafluoroethylene copolymer (E
Table 1 shows the results of examining the moisture absorption rate and moisture permeability, which are evaluation factors of the element reliability, of the optical wiring component manufactured using TFE).
The results are as shown in the following, and the moisture absorption rate is 1% or less, and the moisture permeability is 1 g · mm / m ² · day or less, which is a good value. It became clear that it was. As shown in Table 1, PCTFE has the best moisture-proof property.
It is desirable to select FE as the film material. On the other hand, since PET is widely distributed in the market, has high versatility and is inexpensive, it is desirable to use PET in order to further reduce the price of optical wiring components.

Table 1 Table showing moisture absorption and moisture permeability of film materials. Film material moisture absorption (%) Moisture permeability (g · mm / m ² · day) PCTFE 0 0.010 to 0.0022 PVdCl 0 0.080 to 0.24 FEP <0.01 0.16 PET <0.8 0.4-0.5 ETFE <0.02 0.65

Further, the fixing jig 13 used in the above embodiment,
2, a pedestal 1 having eight V-grooves is formed as shown in FIG.
A resin-made part composed of 7 and a holding lid 18 with a pawl was used. Eight V-grooves are formed on the pedestal 17 with a pitch interval of 250 microns and a pitch error of 1 micron or less, and if the fibers are arranged thereon, the fibers can be precisely aligned.
When the fibers are aligned and then held down by the holding lid 18, the claws formed on the holding lid are fitted into the recesses formed at the predetermined positions of the pedestal, so that the fiber ends can be fixed. The use of the resinous component is effective not only in preventing damage to the fixing jig during the working process and damage to the interposed fiber, but also in reducing the complexity of the structure shown in FIG. This is because it can be easily manufactured. Further, in order to maintain the pitch interval and the pitch accuracy, a resin-made V-grooved pedestal is made of epoxy resin mixed with quartz beads having high molding accuracy. In addition, an injection molding method suitable for mass production and suitable for cost reduction of parts was used.

The optical wiring component manufactured as described above has an 8
Since the core optical fibers can be connected collectively, the time required for the connection can be reduced to 1/8 compared with the conventional optical wiring in which eight single-core optical fibers are connected, and the arrangement order of the wiring at the terminal positions Is fixed in advance, so that no wiring error occurs. Further, according to the above-described method for manufacturing a wiring component, the cost of the wiring component itself can be significantly reduced because high-speed and mass-production can be performed by an automation device. Also, since the present optical wiring component is in the form of a flat film, the space occupied by the optical wiring component has been reduced,
The miniaturization of the device using the optical wiring component has been realized.
Furthermore, since this optical wiring component is flexible with respect to bending in the optical fiber arrangement direction and the vertical direction, the optical input / output terminal mounted on the optical board has a large tolerance for slight positional displacement, and the optical It has the advantage of high convenience in mounting.

Further, as described above, since the residual stress in the fiber portion is extremely small in the present optical wiring component, there is an advantage that the long-term reliability is high as compared with the conventional wiring method in which eight fibers are bundled and fixed. doing.

In the above embodiment, since the production of the optical wiring component and the mounting on the optical board were performed continuously, the fiber was fixed with a thermocompression bonding film, and then the fixing jig was removed. When manufacturing and mounting on an optical board were performed separately, the resin fixing jigs 13 and 14 were left attached. This is because the fiber end of the optical wiring component is protected by the resin fixing jig and a large amount of the optical wiring component can be prepared. The optical wiring components that were mass-produced and packaged in a lump in this way were later transported to the mounting department, where the fixing jig was removed and mounted on the optical board during mounting. In this way, if the fixing jig is left attached, the end portion can be protected and a large amount of optical wiring components can be packed and delivered with high reliability. The resin fixing jig used at this time can be disposable if a resin fixing jig formed by injection molding is used, and the workability is further improved. This is because the price of the resin-made fixing jig by injection molding is extremely low, and the effect of reducing the work cost by improving the workability by disposables exceeds the price of the fixing jig.

[0022]

[Embodiment 2] An example in which an optical wiring component (Fig. 3a) for eight-core batch connection having a J-shaped wiring path is manufactured will be described.

In manufacturing the optical wiring component of the present invention,
First, eight optical fibers drawn from the eight optical fiber bobbins 32 are closely aligned in parallel on the same plane, and are fixed with a fixing jig 33. Next, the other end of the fiber array is fixed with a fixing jig 34 (FIG. 3B). At this time, the attachment position of each fiber to the fixing jig 34 is determined by the product of the pi and the bending radius when the fiber length between the fixing jigs 33 and 34 is based on the fiber length at the most end. The position is set to be longer by the length corresponding to This reflects the difference in the wiring path length between the fibers in the J-shaped wiring path. Next, the fixing jig 34 is cut on the fiber bobbin side. Thereafter, the fixing jigs 33 and 34 are arranged at predetermined positions of the optical wiring component (FIG. 3C). At this time, since the fiber length of each fiber is set to be equal to the length of the wiring path, each fiber is automatically arranged in the same plane by the proper position of the fixing jigs 33 and 34. Thereafter, the eight fibers are fixed by sandwiching the optical fiber portion between the pair of films with adhesive 35 and 36 from the direction perpendicular to the arrangement surface. FIG. 3D is a diagram observed from the fiber arrangement direction and the vertical direction. The films 35 and 36 with adhesive are arranged so as to cover the wiring portion, and are cut into a J-shape according to the wiring shape. FIG. 3d 'is a diagram observed from the fiber arrangement direction. Thereafter, the fixing jig was removed, the end of the fiber array was removed, the excess length of the fiber was processed by cleaving the end face, and the end face of the fiber was processed to complete the optical connection component.

In an optical component having a wiring configuration that does not require rearrangement of the fibers when fixing the fiber as in the present embodiment, a film with an adhesive can be used for fixing the fiber, which is necessary when a thermocompression bonding film is used. Is unnecessary. Therefore, the optical wiring component can be manufactured more quickly.

The optical wiring component manufactured as described above has an 8
Since the core optical fibers can be connected collectively, the time required for the connection can be reduced to 1/8 compared with the conventional optical wiring in which eight single-core optical fibers are connected, and the arrangement order of the wiring at the terminal positions Is fixed in advance, so that no wiring error occurs. Further, according to the above-described method for manufacturing a wiring component, the cost of the wiring component itself can be significantly reduced because high-speed and mass-production can be performed by an automation device. Also, since the present optical wiring component is in the form of a flat film, the space occupied by the optical wiring component has been reduced,
The miniaturization of the device using the optical wiring component has been realized.
Furthermore, since this optical wiring component is flexible with respect to bending in the optical fiber arrangement direction and the vertical direction, the optical input / output terminal mounted on the optical board has a large tolerance for slight positional displacement, and the optical It has the advantage of high convenience in mounting.

[0026]

Embodiment 3 An example in which an optical wiring component for outputting eight optical signals input from one terminal to two different terminals alternately by four is described.

The optical wiring component 31 has the wiring configuration shown in FIG. 3A, and the optical wiring component 41 alternately converts eight optical signals output from the 8-core V-groove optical demultiplexing circuit 42 from above into V-grooves. The optical receiver array 43 is guided to a 4-core MT connector 44 which is an optical output terminal.

In manufacturing the optical wiring component of the present invention,
First, 8 is cut to a predetermined length in advance,
The optical fibers of the book are closely aligned in parallel on the same plane,
It is fixed with a fixing jig 45 (FIG. 4B). The eight optical fibers 51, 52, 53, 54, 55, 56, 57, 58
Among them, 52, 54, 56, and 58 have the same wiring path length because they are the same, and for 51, 53, 55, and 57, the length of each fiber reflects the difference in the wiring path length. The length is increased by a length corresponding to the product of the pi and the bending half with reference to the length of 51. Next, the other end of the fiber row is alternately fixed to the MT connector 44 and the fixing jig 46 from the left (FIG. 4C). Thereafter, as shown in FIG. 4D observed from the fiber arrangement direction and the perpendicular direction, and FIG. 4D ′ observed from the fiber arrangement direction, the MT connector 44 and the fixing jigs 45 and 46 are arranged at predetermined positions of the optical wiring component. The optical fiber portion was sandwiched between the pair of thermocompression-bonding films 48 and 49 from the direction perpendicular to the arrangement plane, and eight fibers were arranged and aligned on the same plane. Finally, the thermocompression-bondable film was heat-compressed to fix the fiber portion, thereby completing an optical connection component.

The optical wiring component manufactured in this manner is placed in advance on an optical mounting board on which an output from an 8-core V-groove optical demultiplexing circuit 42 and an optical receiver array 43 with V-groove are mounted. Fiber terminals were fixed and mounted on V-grooves provided in the wave circuit 42 and the optical receiver array 43. In this optical wiring component, since the optical fiber ends are arranged and arranged, they can be arranged and arranged collectively when mounted on the V-groove, so that the fiber can be fixed with an automated device and connected with a single-core optical fiber. The work time required for connection can be reduced to 1/5 or less as compared with the optical wiring, and the arrangement order of the wiring at the terminal positions is fixed in advance, so that no wiring error occurs. Further, according to the above-described method for manufacturing a wiring component, the cost of the wiring component itself can be significantly reduced because high-speed and mass-production can be performed by an automation device. Also, since the present optical wiring component is in the form of a flat film, the space occupied by the optical wiring component has been reduced,
The miniaturization of the device using the optical wiring component has been realized.
Furthermore, since this optical wiring component is flexible with respect to bending in the optical fiber arrangement direction and the vertical direction, the optical input / output terminal mounted on the optical board has a large tolerance for slight positional displacement, and the optical It has the advantage of high convenience in mounting.

In the above embodiment, the fiber lengths are set so that the fibers having the same wiring route are closely connected to each other. It is also possible to set the fiber length for the purpose of adjusting the skew (difference in the propagation speed of the signal transmitted in the fiber). It was able to be realized.

[0031]

Embodiment 4 This is an embodiment showing a method of fixing aligned fibers held at least partially between a thermocompression bonding film or a film with an adhesive, and heating / vacuum using a heat sealing film. Shown below is how to produce an optical fiber laminate by pressing under pressure. Here, a polyethylene ionomer was used as the heat sealable film.

First, the wired optical fiber 61 is laminated with a laminating film 62 such as polyvinyl chloride, polyethylene terephthalate film and a thermal adhesive (melting point 80
C.) 63 (FIG. 5a). Next, the heat sealing film 64 is heated by the heater 65 under vacuum (1).
30 [deg.] C.) so that heat sealing is possible (FIG. 5).
b). The heated heat-sealable film 64 is extended and arranged on the upper part of the laminating film 62 (FIG. 5).
C), heat sealable film 64 under heating and vacuum
Over the laminating film 62 (FIG. 5).
d). Thus, the heat-sealing film 64 starts sealing, and presses the laminating film 62. The optical fiber laminate produced by this method did not show any damage to the optical fiber, and sufficient pressure was applied to the details corresponding to the irregularities of the optical fiber.

As the laminating film / substrate used here, various plastics, metals and ceramics could be similarly laminated.

The conventional method of laminating an optical fiber is that the wired optical fiber is sandwiched between a laminating film or a substrate coated with an adhesive, and then pressed by using a rubber roller or a flat plate press at room temperature or under heating. (Eg, RA Nordin, “Op.
physical Interconnection Fou
nations and Application
s ", Artech House, Inc., p65
(1994)). However, since the optical fiber lacks mechanical strength, pressurization by this method causes breakage. In addition, the diameter of the optical fiber is as small as about 0.3 mm, and minute irregularities are formed during lamination. With this method, it is not possible to apply sufficient pressure to the details corresponding to the irregularities. However, by laminating the optical fiber by applying pressure under heating and vacuum using a heat-sealing film as in the method of Example 4, it is possible to prevent damage to the optical fiber and to provide a sufficient amount of detail corresponding to the unevenness of the optical fiber. Can be pressurized.

[0035]

Embodiment 5 Next, a method for producing an optical fiber laminate by pressing at least a part of the aligned fibers using a heat-sealing film under heating and vacuum will be described. That is, it shows a manufacturing method when a heat-sealing film is used as a laminating film. As the heat-sealing film, a polyethylene ionomer was used.

The wired optical fiber 61 is formed on a laminating film 62 such as polyvinyl chloride, polyethylene terephthalate film, and a heat adhesive (melting point 80 ° C.) 63 (FIG. 6A). That is, in the state of FIG. 5A of the fourth embodiment, the configuration is such that the upper laminating film 62 is removed. Next, the heat sealing film 6
4 is heated (130 ° C.) by a heater 65 under vacuum to make it heat sealable (FIG. 6B). The heated heat-sealable film 64 is extended and arranged on the aligned optical fibers 61 (FIG. 6C), and the heat-sealable film 64 is put on the upper part while heating and under vacuum (FIG. 6D).

When this manufacturing method was used, good lamination was possible without applying pressure reflecting the heat sealing property, and no breakage of the optical fiber was observed. That is, when the heat-sealing film is used as the upper laminating film in Example 5, lamination can be performed without applying pressure.

[0038]

As described above, according to the optical wiring component and the method of manufacturing the same according to the present invention, the problems of the conventional optical wiring component can be solved, labor can be saved in the connection work, and the connection work time can be reduced. The optical board can be shortened, mass production and cost reduction of the optical board can be realized, the space occupied by the wiring portion is reduced, and high-density mounting of optical components and miniaturization of the device are realized. Further, if the optical fiber is laminated by applying pressure under heating and vacuum using a heat-sealing film, damage to the optical fiber can be prevented, and sufficient pressure can be applied to the details corresponding to the unevenness of the optical fiber. When the heat-sealing film is used as a laminating film, lamination can be performed without applying pressure.

[Brief description of the drawings]

FIG. 1a is a diagram showing an embodiment of a first optical wiring component.

FIG. 1b is a process chart showing an embodiment for manufacturing a first optical wiring component.

FIG. 1c is a process chart showing an embodiment for manufacturing a first optical wiring component.

FIG. 1d is a process chart showing an embodiment for manufacturing a first optical wiring component.

FIG. 1d ′ is a view of FIG. 1d as seen from a vertical direction.

FIG. 2 is a perspective view showing an example of a fixing jig.

FIG. 3A is a diagram showing an embodiment of a second optical wiring component.

FIG. 3B is a process diagram showing an embodiment for manufacturing the second optical wiring component.

FIG. 3c is a process diagram showing an embodiment for manufacturing the second optical wiring component.

FIG. 3d is a process chart showing an embodiment for manufacturing the second optical wiring component.

FIG. 3d 'is a view of FIG. 3d as seen from the vertical direction.

FIG. 4A is a diagram showing an embodiment of a third optical wiring component.

FIG. 4b is a process chart showing an embodiment for manufacturing a third optical wiring component.

FIG. 4c is a process chart showing an embodiment for manufacturing a third optical wiring component.

FIG. 4D is a process drawing showing an embodiment for manufacturing the third optical wiring component.

FIG. 4d 'is a view of FIG. 4d as seen from the vertical direction.

FIG. 5A is a process chart showing an embodiment for manufacturing a fourth optical wiring component.

FIG. 5B is a process chart showing an embodiment for manufacturing a fourth optical wiring component.

FIG. 5c is a process chart showing an embodiment for manufacturing a fourth optical wiring component.

FIG. 5D is a process drawing showing an embodiment for manufacturing the fourth optical wiring component.

FIG. 6a is a process chart showing an embodiment for manufacturing a fifth optical wiring component.

FIG. 6B is a process chart showing an embodiment for manufacturing a fifth optical wiring component.

FIG. 6c is a process chart showing an embodiment for manufacturing a fifth optical wiring component.

FIG. 6D is a view showing the step of the embodiment for manufacturing the fifth optical wiring component;

[Explanation of symbols]

11, 21, 51, 52, 53, 54, 55, 56, 5
7, 58, 61 Single-core optical fiber 15, 16, 35, 36, 48, 49, thermocompression-bondable film 13, 14, 33, 34, 45, 46 Fixing jig 12, 32 Fiber bobbin 17 Resin for fixing jig Pedestal with flexible V-groove 18 Holding lid with resin nail for fixing jig 42 8-core V-groove optical demultiplexing circuit 43 V-groove optical receiver array 44 4-core MT connector 62 Laminating film 63 Heat adhesive 64 Heat seal Film 65 heater

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04B 10/13 10/12 (72) Inventor Shunichi Higashino 3-19-2 Nishishinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Koji Sato Nippon Telegraph and Telephone Corporation, 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo (72) Inventor Yoshito Shuto 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (7)

[Claims] 1. An optical wiring component in which a wiring shape is maintained by fixing at least a part of a plurality of optical fiber core wires, wherein the fiber is fixed using a thermocompression bonding film or a film with an adhesive. 2. The optical wiring component according to claim 1, wherein the film material is polychlorotrifluoroethylene (PC).
TFE), polyvinylidene chloride (PVdCl),
Tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyethylene terephthalate (PE
T), ethylene-tetrafluoroethylene copolymer (E
An optical wiring component using any one of TFE). 3. The optical wiring component according to claim 1, wherein the end is terminated by a multi-core connector. 4. A fiber is cut to a length corresponding to the length of a wiring path, and its ends are aligned and fixed at predetermined positions and angles at input / output ends. The optical wiring component is manufactured by arranging the fibers between the fixed ends and fixing at least a part of the aligned fibers with a thermocompression-bondable film or a film with an adhesive. Manufacturing method of wiring components. 5. The method for manufacturing an optical wiring component according to claim 4, wherein a resin component having a V-groove for fixing an end is used. 6. The method for manufacturing an optical wiring component according to claim 4, wherein at least a part of the aligned fibers is fixed by sandwiching with a thermocompression film or a film with an adhesive. A method for producing an optical wiring component, wherein the method uses a contact pressure action. 7. A method for manufacturing an optical wiring component according to claim 4, wherein at least a part of the fibers arranged on the thermocompression bonding film or the film with adhesive is fixed by covering with a heat sealing film. Manufacturing method of optical wiring components.