The present invention relates to a connector for two-way optical communication. More particularly, the invention relates to an optical connector in which there are incorporated a light-emitting device, a light-receiving device, and a sleeve for optically connecting the light-emitting device, the light-receiving device, and an optical fiber to which an opposed optical plug is attached.
A pair of housing chambers 12 is formed in a housing 11 of an optical connector 10. A light-emitting device module (a sending module) 13 and a light-receiving device module (a receiving module) 14 are respectively housed in these housing chambers 12. Ahead of each of the two housing chambers 12, a guide pipe 15 which extends forward is provided, and a sleeve 16 is inserted into each of these guide pipes 15. In
On the other hand, as shown in
When the optical plug 20 is fitted into the optical connector 10, the optical connector 10 and the optical plug 20 being constructed as described above, the pair of ferrules 21 holding the optical fiber 22 is inserted into the guide pipe 15 and a leading end surface of the ferrule 21 at which an end surface of the optical fiber 22 is exposed becomes opposed, via a very small gap, to a leading end surface of the sleeve 16 which is inserted into the guide pipe 15, whereby the two optical fibers 22, the light-emitting device module 13, and light-receiving device module 14 are each optically connected via the sleeve 16. Incidentally, the sleeve 16 has such a construction that, for example, an optical fiber 16a is housed in a cylindrical holder 16b (for example, Japanese Patent Application Laid-Open No. 2000-193849).
Incidentally, connectors for two-way optical communication as described above are used in various applications. For example, in the case of car-mounted applications, under some environmental conditions and in some handling ways, such connectors for two-way optical communication have had the problem that chemical substances such as oils and solvents adhere.
However, as shown in
The liquid chemical substance which has entered the gap between the peripheral surface of the sleeve and the hole adheres to the peripheral surface of the sleeve in a wide area, does not vaporize and apt to remain for a long period of time. And it has been difficult to wash away the chemical substance even by cleaning the connector with water and the like.
On the other hand, from the standpoint of cost, sleeves made of resin are generally used. If liquid chemical substances such as oils, solvents and chemicals which adhere to a sleeve are left as they are in a case where the sleeve material is resin, erosion and melting proceed gradually and transmittance and surface roughness worsen, thereby posing the problem that the optical function of the sleeve decreases.
Therefore, the present invention has as its object the provision of an optical connector which can suppress a decrease in the optical function of a sleeve even when a liquid chemical substance enters the connector.
The present invention relates to an optical connector which is connected to an optical plug holding an optical fiber to which a ferrule is attached. An optical connector of the present invention has a light-emitting device or a light-receiving device; a sleeve for light-emitting device which optically connects the light-emitting device or the light-receiving device and the optical fiber; and a guide pipe which positions the sleeve and has a supporting portion on an inner circumferential surface thereof so that a space is formed between the guide pipe and the sleeve.
According to the present invention, the sleeve is not attached by being inserted into a guide pipe as in a conventional way; the sleeve is supported and positioned by a supporting portion which is provided in a protruding manner on an inner circumferential surface of a guide pipe. And when liquid chemical substances such as oils and solvents enter the connector, it is only in places where the supporting member is in contact with the sleeve that the chemical substances may be drawn in by the capillary phenomenon. Therefore, the phenomenon that the chemical substances adhere to the peripheral surface of the sleeve in a wide area and remain as in a conventional manner does not occur. That is, it is possible to suppress the occurrence of the problem that the transmittance and surface roughness of the sleeve worsen due to the adhesion and remaining of liquid chemical substances, resulting in a decrease in the optical function of the sleeve. It is possible to obtain an optical connector suitable as an optical connector which is required to provide chemical resistance and oil resistance, for example, in car-mounted applications.
With reference to the accompanying drawings, how the present invention is to be carried out will be described by using embodiments.
The light-emitting device module 31 and the light-receiving device module 32 each have such a construction that a light-emitting device and a light-receiving device are respectively resin encapsulated and a terminal is drawn out from the resin for encapsulation. The light-emitting device is, for example, a laser diode (LD), and the light-receiving device is, for example, a photodiode (PD). In
A concavity 41 into which a mating optical plug is inserted is formed on a front surface of the connector body 401. A pair of guide pipes 42, into which a ferrule attached to a terminal end of an optical fiber is inserted, is formed in a manner protruding from a bottom surface of this concavity 41. In the inner space of the guide pipe 42, the back side of the connector body 401 is open. A supporting portion which supports and positions the sleeve 35 is formed in a protruding manner on the deep recess side (back side) of an inner circumferential surface of this guide pipe 42.
In this embodiment, the supporting portion is constituted by five convexities 43 which extend in the direction of an axis center of the guide pipe 42. The convexities 43 are arranged at equiangular intervals in the circumferential direction of the inner circumferential surface of the guide pipe 42. The leading end side of each of the convexities 43 facing the axis center of the guide pipe 42 has an acute-angled shape, and the leading end has a shape obtained by slightly cutting the acute-angled shape. Therefore, the area of contact surfaces between the convexity 43 and the sleeve 35 is very small. Incidentally, in this embodiment, wide portions of the convexities 43 on the base side (the side facing the inner circumferential surface of the guide pipe 2) are connected to each other. An end surface 43a of the convexity 43 on the front side (the side where the ferrule is inserted) is a ferrule abutment surface.
The sleeve 35 is attached to a portion where the convexity 43 is formed in the guide pipe 42 by being pressed into this portion. As a result of this, as shown in
The light-emitting device module 31, the light-receiving device module 32, the device holder 33, and the shield cover 34 are attached to the connector body 401, to which the sleeve 35 has been attached. The light-emitting device module 31 and the light-receiving device module 32 are housed in the device holder 33 and held thereby, and this device holder 33 is housed in the shield cover 34 and held thereby. The shield cover 34 is attached to the connector body 401 from the back side thereof, whereby the optical connector is completed. Incidentally, the shield cover 34 is fixed in such a manner that right and left engaging portions thereof (not seen in
The pair of sleeves 35 is provided in such a manner that an end surface on the back side is opposed to a light-emitting surface of the light-emitting device module 31 and a light-receiving surface of the light-receiving device module 32. An end surface of the sleeve 35 on the front side is disposed in the same place as the end surface 43a of the convexity 43 on the front side, which is a ferrule abutment surface. An optical fiber which is inserted into the guide pipe 42 by being held by a ferrule, the light-emitting device module 31, and the light-receiving device module 32 are each optically connected by the sleeve 35 which is thus arranged.
In the optical connector having this construction, the sleeve 35 is supported and positioned by the leading ends of the five convexities 43. That is, the leading ends of the convexities 43 only slightly come into contact with the peripheral surface of the sleeve 35 and the space 44 is present in the greater part of the peripheral surface. Therefore, gaps into which liquid chemical substances may be drawn in by the capillary phenomenon are only small portions with which the leading ends of the convexities 43 are in contact. Accordingly, even when a liquid chemical substance enters the guide pipe 42, the amount of the liquid chemical substance which is drawn in by the capillary phenomenon and remains on the peripheral surface of the sleeve 35 is small. Therefore, it is possible to substantially suppress the occurrence of the phenomenon that the optical function of the sleeve 35 decreases due to the adherence of liquid chemical substances for a long period of time.
When a liquid chemical substance has entered the guide pipe 42, it is possible to wash away the chemical substance with streams of water and the like from the outside by utilizing the space 44. Also in this respect, it is possible to reduce the amount of a chemical substance adhering to the peripheral surface of the sleeve 35.
Incidentally, by giving an acute-angled shape to the leading end side of the convexity 43, it is possible to form the space 44 having sufficient dimensions (width and depth). Furthermore, by making the base side of the convexity 43 wide, it is possible to ensure the strength of the convexity 43.
The construction of the supporting portion which supports and positions the sleeve 35 is not limited to that of this embodiment, and it is possible to adopt various constructions. Other constructions of the supporting portion will be described below. Incidentally, in each of the embodiments given below, the constructions are shown by drawings similar to
In this embodiment, the description has been given of an optical connector which has both a light-emitting device and a light-receiving device and is provided with two sleeves. However, the present invention is not limited to this. The present invention can also be applied to an optical connector which has either a light-emitting device or a light-receiving device and is provided with only one sleeve.
In this embodiment, in the same way as in Embodiment 1, a supporting portion which supports and positions a sleeve 35 is constituted by five convexities 45. As with the convexities 43 of Embodiment 1, these convexities 45 have an acute-angled shape at the leading end side, part of the leading end of each convexity is cut, and the base side is wide. However, in the convexity 43, the inclined surface (side surface) from the leading end to the base is formed by a curved surface widening toward the base, whereas the inclined surface (side surface) of the convexity 45 is flat. That is, the convexity 45 has an acute-angled triangular shape in section.
Unlike the convexities 43, the convexities 45 are not connected to each other on the base side. The convexities 45 are formed on an inner circumferential surface of a guide pipe 42 independently of each other. An end surface 45a of the convexity 45 on the front side is a ferrule abutment surface. Furthermore, an annular ferrule stop 46 is formed on the inner circumferential surface of the guide pipe 42 so as to be flush with the end surface 45a (the leading end side of the convexity 45).
In the construction of this embodiment, as shown in
In the case of the convexities 45 of
In contrast to this, in the case of
In
In this embodiment, as shown in
The sleeve 35 is supported by being fitted into the holes 51 of the two annular plate portions 52. There is a large space 53 between the sleeve 35 and the guide pipe 42 in places other than the places where the sleeve 35 is supported by the annular plate portions 52. Incidentally, out of the two annular plate portions 52, the annular plate portion 52 which is positioned on the side where a ferrule is inserted (the front side) provides a ferrule abutment surface. Around the hole 51 on the back side of each of the annular plate portions 52, there is formed a guiding chamfer (tapered surface) 52a so that the sleeve 45 is easily inserted.
Even in the case of a construction in which the sleeve 35 is supported and positioned by such annular plate portions 52, the area in which supporting portions are in contact with the peripheral surface of the sleeve 35 is small. Therefore, even when a liquid chemical substance has entered the guide pipe 42, it is possible to ensure that the amount of the liquid chemical substance which adheres to the peripheral surface of the sleeve 35 due to the capillary phenomenon and remains therein is small.
In this embodiment, a convex piece 54 is provided in place of the annular plate portion 52 of Embodiment 3. As shown in
Out of the convex pieces 54 in the two places, the pair of convex pieces 54 present in the front side provides a ferrule abutment surface. In this example, an annular ferrule stop 55 is formed in the guide pipe 42 which is flush with the ferrule abutment surface. Incidentally, a chamfer 54b is formed at the leading end of each of the convex pieces 54 on the back side.
By being inserted into a gap between the convex pieces 54 which radially form a pair, the sleeve 35 is supported in a sandwiched manner and positioned by the convex pieces 54. In the case of this embodiment, a supporting portion does not have a construction in which the guide pipe 42 is covered and, therefore, a space 53 is open to the outside. Therefore, even when a liquid chemical substance has adhered to the peripheral surface of the sleeve 35, the optical connector is easily cleaned.
In this embodiment, as shown in
In this embodiment, as shown in
Out of the protrusion 56 in the two places, the protrusion 56 on the front side constitutes a ferrule abutment surface. In this embodiment, an annular ferrule stop 55 is also provided. Incidentally, the five protrusions 56 present in the two fore-and-aft places are arranged so that they do not overlap each other as viewed from the axial direction.
The sleeve 35 is inserted into the parts in the guide pipe 42 where the protrusions 56 are formed and the sleeve 35 is supported and positioned by being pinched between the leading ends of the protrusions 56.
This embodiment is an example in which a groove is added between the convexities 45 within the guide pipe 42 of Embodiment 2. As shown in
In this embodiment, places where a liquid chemical substance is drawn in by the capillary phenomenon are intentionally provided by the fine grooves 57 and these places are limited. By thus forming the fine grooves 57 on the inner circumferential surface of the guide pipe 42 away from a sleeve 35, it is possible to minimize the amount of a liquid chemical substance remaining on the peripheral surface of the sleeve 35.
This embodiment is an example in which a hole 58 as shown in
By thus providing the hole 58 in the guide pipe 42, even when a liquid chemical substance has entered the guide pipe 42, the cleaning of the optical connector can be satisfactorily performed.
In this embodiment, slits 61, 62 shown in
Although in Embodiment 8 the hole 58 is provided in the guide pipe, such slits 61, 62 may be provided. As a result of this, the cleaning of the optical connector can be more easily performed and the cleaning can be efficiently performed.
In the guide pipe 42 of Embodiment 6, the five protrusions 56 are provided in each of the two places in the axial direction. In this embodiment, the five protrusions 56 on the back side are eliminated so that the supporting portion of the guide pipe 42 is provided only in one place. And the connector body 4010 supports and positions a connection 36 which connects the two sleeves 35.
As shown in
The connection 36 is attached to the concavity 63 having the protrusions 64 by being pressed therein. And the four protrusions 64 fix and position the connection 36.
In this embodiment, the supporting portion which comes into contact with the sleeve 35 is only in one place at the leading end of the sleeve 35. Therefore, the number of places where a liquid chemical substance adheres and remains can be further reduced. Incidentally, if a liquid chemical substance adheres to the portion which fixes the connection 36, no problem arises because the connection 36 does not relate to the optical function.
The present invention has been described above by using the various embodiments. Conventional techniques had the problem that due to contact of the whole peripheral surface of a sleeve with a guide pipe, liquid chemical substances are drawn in by the capillary phenomenon. According to the present invention, a sleeve is supported and positioned by supporting portions, such as convexities, annular plate portions, convex pieces and protrusions in the guide pipe. Therefore, because it is possible to reduce the area of contact of the supporting portions with the sleeve, it is possible to substantially reduce the amount of a liquid chemical substance which is drawn in by the capillary phenomenon and remains.
Incidentally, although in Embodiments 1 and 2 five convexities 43, 45 are respectively provided, the number of the convexities is not limited to five and it is necessary only that at least three convexities be provided. The sleeve 35 can be positioned and supported by providing three convexities. Similarly, in Embodiment 6, five protrusions 56 are provided each in two places of the guide pipe 42 in the axial direction. However, it is necessary only that also this protrusion 1 be provided in quantities of at least three in one place.
In Embodiments 3 to 6, supporting portions, such as the annular plate portions 52, the convex pieces 54 and the protrusions 56, are provided each in two places in the axial direction of the guide pipe 42. However, such supporting portions are not limited to two places and may be provided in three or more places in the axial direction of the guide pipe 42.
Although the leading end of the convexities 43, 45 in Embodiments 1 and 2 and the leading end of the protrusions 56 in Embodiment 6 are each cut a little, it is also possible that the leading ends have an acute-angled shape without being cut.
Number | Date | Country | Kind |
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2005-161580 | Jun 2005 | JP | national |
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