Optical waveguides – With disengagable mechanical connector – Optical fiber/optical fiber cable termination structure
Reexamination Certificate
2002-02-07
2004-02-10
Zarroli, Michael C. (Department: 2839)
Optical waveguides
With disengagable mechanical connector
Optical fiber/optical fiber cable termination structure
C385S092000, C385S077000
Reexamination Certificate
active
06688780
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a light-blocking shutter in a fiber-optic connector or adapter that prevents light emissions from the fiber-optics of the connector when the adapter is open (i.e., when no mating connector is inserted). This prevents eye damage if a person should look into the open end of the connector that is carrying an optical signal. More specifically, the invention relates to light-blocking shutters in fiber-optic adapters that automatically block the opening through which the light signal is transmitted when a mating connector is removed and automatically open when the mating connector is inserted.
2. Description of the Prior Art
FIG. 1
, labeled “Prior Art,” shows a typical fiber-optic connector C with a ferrule F, having centrally-located optical fiber (or fibers) O terminating at its surface, extending from the end of a connector body B
1
. Outer body B
2
slides over connector body B
1
. It is well known that damage to the end of the optical fiber O itself (dirt or scratches) can also cause severe scattering of the light beam emitted from the optical fiber O and insertion loss, potentially rendering the connector C inoperative.
Since the light used in fiber optic communications is generated by lasers, the light can potentially cause damage to the eyes. The recent trend toward more powerful signal lasers has made fiber optics more dangerous than they were previously. Thus, a number of patents disclose fiber-optic adapters with spring-loaded shutters that are pushed inward by the insertion of a male connector to prevent light emissions from the adapter. U.S. Pat. No. 6,004,043 to Abendschein et al., for example, discloses a spring-loaded shutter door that is disposed at an angle &thgr; inwardly into the receptacle and is pushed out of the way by the inserted male connector (Col. 3, lines 50-54). The inserted male connector contacts the shutter near the sping-loaded hinge, which requires a greater force than if the connector contacted the shutter at a distance from the spring-loaded hinge.
U.S. Pat. No. 6,142,676 to Lu discloses an internal beam stop door. The door is biased by a spring and limited by stop posts (Col. 4, lines 6-21). The door is angled at about 20° off the transverse. As seen in FIGS. 23-27, the door is first pushed inward by a cover and then by a prong (FIG. 24). Once the door is held up out of the way, continued insertion operates a cam mechanism that raises the cover (FIG. 26) so that it comes to rest against the raised door (FIG. 27).
It is noted in Lu that slanting the shutter does not actually increase the leverage and does nothing to solve the leverage problem discussed above, as long as the engagement is laterally near to the hinge. This is because the torque required to open the shutter is the product of the force and the distance from the line of the force to the hinge. The line of force extends parallel to the motion of the male connector.
U.S. Pat. No. 6,108,482 to Roth discloses as one of its objects the prevention of damage to the tip of a male optical-fiber connector (Col. 1, line 61, to Col. 2, line 6). Roth shows a spring-loaded shutter in which the shutter surface is divided into a recessed area and a surrounding ledge having a raised surface (Col. 3, lines 47-49 and lines 59-61). The male connector that pushes open the shutter has a projecting optical fiber ferrule with a “front mating face” that “engages outer surface of shutter and automatically opens the shutter” (Col. 4, lines 11-14). The shutter's recess is intended to protect the central area of the mating face, where the fiber termination is located: “Recessed area has a depth such that the polished ends of the optical fibers are protected” (Col. 4, line 17). The fiber termination, but not the ferrule itself, is protected.
The structure disclosed in Roth has several disadvantages. When the ferrule hits the shutter it is subjected to forces that would better be taken by the shoulder of the connector body surrounding it. Roth actually teaches against opening the shutter by pushing it with anything except for the ferrule, stating that the recess “should be designed with a depth slightly less than the distance the ferrule projects from the fiber optic connector” (Col. 3, lines 53-55; Col. 2, lines 32-34).
The above-cited hinged or spring-loaded shutters also have the disadvantage that they require additional manufacturing steps to insert both the shutter and the hinges and/or springs associated with the shutter. In addition, if the hinges or springs fail, the shutter will become inoperative within the adapter because the shutter will fail to automatically return to the light blocking position. Non-spring loaded shutters, like those mounted in a cantilevered manner, would potentially eliminate this problem.
U.S. Pat. No. 5,104,242 to Ishikawa, for example, discloses a flexible, light-impermeable shutter that covers the optical path of light from a fiber optic source by blocking a portion of the insertion passage inside the adapter. It is connected near the opening of the passage in a cantilevered manner as best seen in FIGS. 1 and 3. Although the shutter is curved so that the sensitive tip of the ferrule does not contact the spring, the ferrule housing contacts the spring during insertion of the connector, as shown in FIG. 3. In Ishikawa, the shutter is located interiorly of the ferrule insertion hole (FIG. 1), which is separate from the insertion passage for the connector body.
U.S. Pat. No. 5,570,445 to Chou et al. discloses a hinged (FIG. 1A) or optionally “resilient tongue” (Col. 8, lines 1-5) light-blocking shutter disposed within a fiber optic adapter. The shutter is attached to the inner surface of the housing of the adapter. Given the configuration of the connector, the ferrule tip (FIG. 2C) contacts the shutter directly when the connector is inserted into the adapter.
U.S. Pat. No. 5,708,745 to Yamaji et al. discloses a pair of mating optical shields formed over the opening of an adaptor insertion passage (FIG. 1) and connected to the opening of the adapter in a cantilevered manner with a spring bias that disposes the shields in a closed position to prevent optical emissions.
U.S. Pat. No. 6,302,592 to Züllig discloses as the prior art, an interiorly disposed, hinged shutter for use with fiber optic adapters for preventing emissions of light (citing U.S. Pat. No. 5,363,460 to Marazzi et al.). Specifically, Züllig shows a spring-loaded, hinged “radiation protection” shutter attached to the housing of the adaptor and forming a cantilever (FIG. 1). A leaf-spring is attached to the lower portion of the shutter to hold the shutter in a light-blocking position when there is no male connector situated in the insertion passage of the adapter (FIG. 1).
SUMMARY AND OBJECTS OF THE INVENTION
In view of the foregoing, it should be apparent that there still exists a need for an apparatus for blocking light emissions from a fiber optic connector in an open adapter using a cantilevered shutter that does not require a hinge or spring, that is designed to swing open by a force exerted far from the connection point, and that uses a simple, inexpensive, and foolproof shape that ensures that the delicate tip of the inserted connector does not contact the shutter, risking damage.
It is, therefore, an object of the invention to provide a fiber optic adapter that has a light-blocking shutter inside the insertion passage of the adapter that prevents light emissions from a fiber optic cable connected to one end of the adapter from causing eye injury.
It is another object of the invention to provide a fiber optic adapter that has a shutter that is attached to the adapter in a cantilevered manner.
It is still another object of the invention to provide a fiber optic adapter that has a shutter made of a material that automatically returns the shutter into a light-blocking position inside the adapter when a male connector is removed from the adapter.
It is another object of the invention to provide a fiber optic adapter that has
Amphenol Corporation
Blank Rome LLP
Zarroli Michael C.
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