Fiber optic slip ring with through bore

The current disclosure shows a fiber optic slip ring with through bore, or an off-axis fiber optic rotary joint to provide transmission of optic data between mechanically rotational interface with a through bore. Said fiber optic slip ring with through bore may include a ring assembly and a brush block assembly within a rotor and a stator. Said ring assembly may include a ring, a ring holder and a fiber. Said brush block assembly may include a fiber brush, a brush block, an optic index matching fluid, and shaft seals. Said ring may be a donut-shaped waveguide with flat surface on one side. Said fiber brush may have an angled-surface, which is fully contacted with said flat surface on said ring at any time so that during the rotation of said rotor, the optic signal can be transmitted between said fiber and said fiber brush in either direction.

BACKGROUND

1. Technical Field

The disclosure is related generally to the field of apparatus for fiber optic communication, and more particularly, off-axis fiber optic rotary joint to provide transmission of optic data between mechanically rotational interface with a through bore.

2. Description of Related Art

It is well known that the devices to transmit optical data between two independently rotational members are called fiber optical rotary joints (FORJ), or fiber optic slip rings. A typical FORJ, consists of a fixed fiber collimator holder and a rotatable fiber collimator holder which are relatively rotatable to each other to allow transmission of optical signals through the rotational interface from fiber collimators on any one of the holders to the fiber collimators on another holder. There are single channel, two channel and multi-channel fiber optical rotary joints.

Almost all of FORJs on the market are categorized as on-axis fiber optical rotary joints because the optical paths are located along the axis of rotation or occupy the central space along the axis of rotation. If the central space along the rotational axis is not accessible, the optical light paths would not be allowed to pass through the central area along the rotational axis. Such devices are usually called off-axis fiber optic rotary joints, or fiber optic slip rings with through bore. Usually there is a through bore along the rotational axis to provide routing space for hydraulics, pneumatics, RF, or other physical media. Application examples of FORJs with through bore, include CT scanners, MRI scanners, tank turrets, marine propulsion systems, helicopters, machine tools, and winches.

In most prior teachings, the off-axis fiber optic rotary joints consist of a plurality of optical transmitters located on the rotor side, and multiple photo diodes on the stator side. The photo diodes are capable of receiving signals from the rotor side. In U.S. Pat. No. 6,907,161, the use of multiple inputs and pick-ups is required to keep the optical signals at a level that is sufficiently high to permit the photodiode receivers to operate. U.S. Pat. No. 6,980,714 proposed an improved off-axis fiber optic rotary joint with an associated reflector assembly trying to provide relatively large data rates, such as 1.25 Gbit/sec and greater. As the data rate increases, a photodiode having a smaller active area is required. The increased ratio of the fiber diameter to the photodiode area makes it more difficult to focus multiple optical signals onto the relatively small active area. In U.S. Pat. No. 8,611,753, an angular position encoder is used to track the location of the rotor relative to the stator such that the channel selector can appropriately switch the various 5.0 Gbit/sec signal streams to their respective sources. The rotor position encoder provides the locations at which the lasers are switched to carry data from another input signal stream.

As a counterpart, electrical slip rings are electromechanical devices that consist of rotatable parts (rotors) and stationary parts (stators). They allow the transmission of electrical signals and power between rotors and stators. A conventional electrical slip ring consists of conductive rings and brushes. Said rings are mounted on said rotor and insulated from it. Said brushes are usually fixed on said stators and run in contact with said rings, rubbing against the peripheral surfaces of the rings, transferring electrical power or signals to the rotor side.

SUMMARY

An objective of the current disclosure is to disclose a fiber optic slip ring with through bore for transmission of optic data between mechanically rotational interfaces with a through bore. The fiber optic slip rings can be single channel or multi-channel.

DETAIL DESCRIPTION

Detailed explanation of some embodiments are disclosed as follows.

FIG. 1shows an embodiment of a single channel fiber optic slip ring. Said slip ring assembly may include rotor31and stator41. They may be relatively rotational through ball bearings81and82. Said rotor31has a through bore01. Inside said stator, there are a ring assembly (shown inFIG. 3) and a brush block assembly (shown inFIG. 5). Said ring assembly includes ring71, ring holder51and optic fiber11. Said brush block assembly includes fiber brush21, brush block42, optic index matching fluid43, shaft seal61and62.FIG. 2is the enlarged view for ring assembly and brush block assembly.

FIG. 4shows the perspective view of an embodiment of ring71. Said ring71is a donut-shaped waveguide with a flat surface on one side. Said ring holder51may have a material that is the same material as the cladding material of said optic fiber11. Said ring holder51has a ring groove with the same donut-shape as said ring71so that said ring71can fit into said ring groove in ring holder51. Said optic fiber11can be fused into said ring holder51from one side of ring holder51. Said ring assembly may be mounted on said rotor31as shown inFIG. 1.

Said brush block42may have a block groove with the same donut-shape as said ring holder51. Said block groove may be filled up with said optic index matching fluid43and sealed by said shaft seals61and62. Said fiber brush21may have an angled-surface on one end. Said brush block42may have a block material that is the same material as the cladding material of said fiber brush21. Said fiber brush21can be fused into said brush block42from one side of brush block42. Said brush block assembly may be fixed with said stator41and has the clearance space “c” relative to said rotor31and said ring assembly respectively.

Said angled-surface on said fiber brush21may be fully contacted with said flat surface on said ring71at any time. So during the rotation of said rotor31, the optic signal can be transmitted between said optic fiber11and said fiber brush21and, in either direction, with either optic fiber11or the fiber brush21transmitting or receiving.

FIG. 6shows an embodiment of a multi-channel fiber optic slip ring. The multi-channel fiber optic slip ring may include multiple ring assemblies and brush block assemblies, Ch1, Ch2, Ch3, Ch4, and more. The quantity of said assembly can be any number. All said ring assemblies may be mounted on the same rotor31, and all said brush block assemblies may be mounted inside said the same stator41. The optic fibers on rotor31are11,12,13,14, and more. The optic fibers on stator41side are21,22,23,24, and more. During the rotation of said rotor31, the optic signal can be transmitted from said optic fibers11,12,13,14and any other optic fibers on the rotor; to said optic fibers21,22,23,24, and any other optic fibers on the stator. With the same configuration the optic signal can be received by optic fibers11,12,13,14and any other optic fibers on the rotor; and transmitted from optic fibers21,22,23,24, and any other optic fibers on the stator.