Optical fiber connector system

Fiber Optic Connector System

Technical field

The invention relates to an optical fiber splicing system. Specifically, the present invention relates to a joint assembly for optically connecting a circuit board and a back plate.

Background technique

The use of optical fiber for high-capacity and high-speed communications has been widely established. With the increase in the capacity of transmitting information, the use of optical cables including multiple optical fibers and the use of multi-optical cable systems continue to grow.

It has long been desired to increase the number of optical fibers that can be detachably connected in a given space. So far, the interconnection of optical fibers has been limited to single or dual specifications using industry standard connectors such as SC, ST, and LC. These solutions are similar to single-ended electrical cable terminations that were popular before the invention of ribbon electrical cables and IDC connectors that can be terminated in large numbers.

At present, fiber optic terminals are developing from a single terminal to a large-scale terminal. In the past few years, ribbon-shaped multi-fiber cables were developed. With the development of these cables, ferrules for installing multi-fibers have also been developed.

Traditional electrical box designs are now being used to accommodate optical and optoelectronic devices. In the design of a traditional electrical box, the electrical box includes a box with a plurality of internal slots or guide rails that are substantially parallel to each other. The components are mounted on a flat substrate, which is called a circuit board or daughter board, and they are designed to slide into slots or rails in the box.

For cables, it is necessary to provide a measure that allows optical fiber signals to pass through the rear panel of the electrical box. The latter name comes from the base (end) surface of the parallelepiped box, which is basically perpendicular to the circuit board. In the present invention, the term "rear plate" refers to an interconnection plane that can form a plurality of interconnections such as a common bus or other external devices. For ease of description, the rear panel is described as having a front or inner surface and a rear or outer surface.

An example of a backplane connection application is the interconnection of telephone switching equipment. In this application, a circuit board with optical and electronic wireless communication components is slid into the box. It is necessary to have an optical fiber terminal that can be detached from the front and rear sides of the rear panel. In addition, as a function of inserting and removing the optical drive card from a track connected to the rear plate, the connection and detachment of the optical connection in the drive card are completed in a concealed manner.

In order to maintain proper transmission of optical signals, the fiber ends should be carefully aligned along the three-dimensional motion (x, y, and z) axes and the angular directions should also be aligned. As the number of optical fibers to be aligned increases, the difficulty of alignment will increase, and the geometric tolerances will decrease. Regarding the alignment and mating force issues along the interconnecting axes, the concealed mating of the circuit board mounting parts and the backplane joints will present special challenges.

For ease of description here, the axis of interconnection is referred to as the longitudinal or x-axis, and it is formed by the longitudinal alignment of the optical fibers at the connection point. Generally, in the application of the rear panel, the longitudinal axis is collinear with the movement axis of the circuit board and the connection axis of the optical fiber in and out of the electrical box. The lateral or y-axis is defined by being perpendicular to the x-axis and the flat surface of the circuit board. Finally, the transverse or z-axis is defined by orthogonal to the x-axis and the rear plate surface. The angular alignment is due to the angular orientation of the circuit board relative to the x-axis.

In a preferred embodiment, the movement of the circuit board sliding into the receiving slot simultaneously realizes the optical interconnection. The "optical gap" distance along the longitudinal axis between the fiber end and the interconnected optical element is an important consideration. Larger gaps hinder effective connections, thus causing loss of optical signals. On the other hand, excessive pressure on the mating surface, such as the pressure caused by a "hard plug" into the circuit board, may cause damage to the fragile fiber ends and mating components. The traditional optical gap tolerance is about less than 1 micron.

The current joint assembly includes a ferrule mounted with a forward biased spring. The biasing spring has two purposes. The first is to absorb a limited amount of overtravel of the ferrule during the mating process, and the second is to provide a predetermined spring biasing force so that when the ferrule is in their mating position, the sleeve The circles are pushed together tightly.

Another issue to consider is the gap between the circuit boards, especially when dealing with back-board connector systems. The circuit board gap refers to the distance maintained between the rear edge of the circuit board and the inner or front surface of the rear board. Generally speaking, designers and users of rear plate connection systems believe that it is extremely difficult to control the position of the circuit board relative to the rear plate within the precise range required for optical interconnection. The circuit board gap (also defined as the circuit board insertion distance) will be affected by many variables. These variables include the length of the circuit board, the position of the components on the surface of the circuit board, the tolerances of the circuit board stop pins, and the position of the components on the rear board.

When the circuit board is inserted relative to the inner surface of the rear plate, a set of conditions are presented, in which, when the components of the rear plate connector are fixed in a mating situation, these components will be subjected to excessive compressive stress. In some cases, the compressive stress is sufficient to cause actual damage to the connector element and the optical fiber contained therein.

Therefore, there is a need for a joint system that can prevent component damage caused by excessive force by the operator, compensate for longitudinal circuit board misalignment, and accurately control the optical fiber gap distance and matching force.

Another issue to consider is the radial misalignment of the circuit board. When the operator inserts the circuit board into a slot, it is often difficult to keep the edge of the circuit board completely aligned with the lateral axis of the rear board. FIG. 1 shows a circuit board 10 with an angular misalignment, and the circuit board 10 has a connector 12 that is matched with a rear plate connector 14. On the other hand, the circuit board is correctly aligned along the y and z axes. At the contact point between the connectors 12 and 14, the angular misalignment can prevent the correct gap space between the optical fibers 16 and cause excessive pressure on one end of the connector and the corresponding fiber end face.

In addition to correct alignment, there are other issues that need to be considered in the rear panel interconnection system. With the emergence of laser optical cables and other high-intensity light sources, eye safety protection has become a major issue related to users of rear panel connectors. The safety problem is more prominent due to the fact that the amount of light has doubled due to the increase in the number of optical fibers. Therefore, compared with the original single optical fiber, the array of ribbon optical fibers will be more dangerous. .

The current system (as discussed in U.S. Patent No. 5,080,461) discusses the use of complex door systems installed on the fiber-terminated splices, but its main purpose is to prevent damage or contamination to the fiber ends. Since the diameter of the light transmission core of a single-mode optical fiber is only about 8 microns, even a small amount of dust accumulation may cause the optical fiber to fail to work. However, the previous system requires a complicated termination at each fiber end, and can only be matched with another corresponding male-female connector pair, but cannot be matched with a standard connector, which makes the use of this system very inconvenient.

EMI (Electromagnetic Interference) control has also become a problem in the design of the rear panel connector. Since connecting the optoelectronic device through the back plate often needs to form an actual hole through the back plate of the electrical box, there is a hidden danger of EMI leakage through the back plate. Electrical connections try to solve this problem by using several sophisticated EMI shielding techniques. However, current optical fiber connectors cannot meet this requirement.

Finally, another issue related to the application of rear plate optical connectors is the control of the bending radius. Due to gravity, operator's misoperation or practical restrictions, such as when the box is pressed against a wall, the horizontal connection of the box is often affected by bending stress. Optical fibers are made of glass, and they rely on total internal reflection to transport optical signals. When the optical fiber is bent beyond a certain critical angle, cracking may occur in the glass, causing the fiber to break or be damaged. Moreover, under certain bending angles, even if the glass optical fiber does not break, the optical signal may not be completely kept inside the optical fiber, so the optical signal may be lost or may be lost.

People try to use several methods and devices to control the bending radius of the optical cable. These methods and devices include pre-formed shields that can slide on the optical cable, external devices such as clips or clamps, and carefully molded components. The shape of these components is set to be when connected to the optical cable At the same time, the optical cable can obtain the shape of the molded structure.

Since backplane connection often involves connecting a large number of optical fibers in a small space, there is a need for a device that can control the bending radius of the optical fibers.

Summary of the invention

The invention relates to an optical fiber connection system, which can provide longitudinal and angular alignment control, contaminant control, visual safety protection, and bending radius control. In a specific embodiment, the optical connection system of the present invention realizes the connection of several arrays of optical cables in a single or collective mode.

The optical fiber connector system of the present invention is designed to connect at least one optical cable installed near the edge of a circuit board on a flat substrate through a back plate. Each optical fiber cable includes a plurality of optical fibers and an end-junction ferrule, and the longitudinal orientation of the optical fiber in the end-junction ferrule forms a longitudinal axis and a forward direction toward the rear plate. Each optical cable can be terminated by a ferrule having a first longitudinal movement range x1 relative to the holding member and a ferrule spring part having a longitudinal ferrule spring force fn.

The optical fiber connector system includes a circuit board or base housing assembly and a back plate housing assembly. The circuit board housing assembly is mounted on a flat substrate or circuit board, and includes at least one ferrule receiving cavity for receiving an optical fiber ferrule. The circuit board housing assembly includes a circuit board housing spring. The circuit board housing assembly has a longitudinal movement range x2 relative to the circuit board, and the circuit board housing assembly spring can control the movement of the circuit board housing assembly along the longitudinal movement range. The circuit board spring has a spring force h in the longitudinal direction, where: h>Σ1nfn]]> That is, the spring force of the circuit board spring can offset the opposite spring force of all ferrule springs. It should be understood that the ferrule spring may include one or more separate spring parts. In an embodiment of the present invention, the circuit board spring includes two more springs laterally spaced apart from each other, thereby forming an independent circuit board suspension, which can compensate for angular misalignment along the xy plane.

The back plate member has a first surface and a second surface. The rear panel housing includes at least one longitudinal receiving cavity, which is matched with a corresponding cavity in the circuit board housing assembly. The receiving cavity has a front opening along the first surface of the rear plate member and a rear opening along the second surface of the rear plate member. One front door covers the front opening, and one rear door covers the rear opening. In a particular embodiment, these doors are spring parts, which are made of flexible, conductive material and are biased to a closed position. To provide EMI protection, the door can be electrically grounded. In another embodiment, the back plate housing includes two members, the first one is connected to the first side of the back plate, and the second one is connected to the second side of the back plate. In order to provide EMI protection, one of the components may include electrically grounded conductive materials.

The connection system may also include one or more optical cables including bending radius control members, which can control the bending radius of the optical cable. The bending radius control member includes a deformation-proof heat-shrinkable outer sheath surrounding the optical cable, wherein the heat-shrinkable outer sheath has a required bending radius curvature.

Description of the drawings

Figure 1 is a side view of a circuit board with a certain angular misalignment and a rear board connector.

Figure 2 is a perspective isometric view of a first embodiment of a joint system according to the present invention in a connected circuit board position.

Figure 3 is an isometric view of the joint system shown in Figure 2 in an unconnected circuit board position.

Fig. 4 is an exploded isometric view of the joint system shown in Fig. 2.

Fig. 5 is an isometric view of the back plate housing assembly of the joint system shown in Fig. 2.

Fig. 6 is an isometric view of the circuit board housing assembly of the joint system shown in Fig. 2.

Fig. 7 is an isometric view of the circuit board-facing surface of the housing assembly of the joint system shown in Fig. 2.

Fig. 8 is a side view of the rear plate connection system, in which the connecting parts are aligned along the interconnecting axis, and the circuit board is inclined with respect to the interconnecting axis.

Fig. 9 is an isometric view of the plug portion of the connection system shown in Fig. 4.

Fig. 10 is an isometric exploded perspective view of the plug shown in Fig. 4, which shows the plug fully assembled except that the cover is not installed.

Fig. 11 is an isometric view of the plug shown in Fig. 4 with the cover installed.

Figure 12 is an isometric view of the plug shown in Figure 4 fully assembled.

Figure 13 is an isometric view of the plug assembly shown in Figure 11 surrounding a shaped fixture.

Figure 14 is an exploded isometric view of the rear panel housing assembly.

detailed description

2 and 3 show an embodiment of the optical interconnection system 100 according to the present invention. The optical interconnection system 100 can connect the circuit board or the daughter board 102 and the back board 104 and pass through the back board. The circuit board 102 is a flat substrate, such as a circuit board or a daughter board, which may include optical, optoelectronic, and electronic components. The circuit board 102 can be slidably inserted into the slot formed by the circuit board guide 106. The back plate 104 includes a through hole 108, a first inner surface 110 and a second outer surface 112.

The optical interconnection system 100 includes a back plate housing 120 placed in the opening 108. In this embodiment, the back plate housing 120 includes a first part 122 and a second part 124. The first part 122 includes a male positioning feature 126 that can mate with a corresponding female feature (not shown) on the rear surface of the second part 124. During assembly, positioning features can help ensure accurate positioning between the back plate housing portions 122 and 124. It should be understood that in some other embodiments, the housing parts 122 and 124 do not need to be separated, but are molded as one piece. However, separating the shell parts 122 and 124 allows more freedom in the design of the core.

In this embodiment, a number of fixing members 128 fix the rear plate housing assembly 120 to the rear plate 104. These fixing members 128 include metal inserts with threads, which are inserted through mating holes 130 in the first and second parts 122 and 124 of the rear plate housing 120. Those skilled in the art can easily understand that the mounting screw can be used in combination with the fixing member 128, and various fixing mechanisms, adhesives, interference fits, and other devices known in the art can also be used to align the back plate shell. The body assembly 120 is aligned and fixed.

In FIG. 4, the back plate housing assembly 120 forms an array of four receiving cavities 132. In other embodiments, it may also include a single receiving cavity, or other required number of cavities capable of accommodating each fiber optic cable connector. Each receiving cavity 132 includes a front opening 134 and a rear opening 136. In order to facilitate the description of the present invention, the terms "rear", "front", "forward" or "backward" are merely illustrative, so as to assist in describing the illustrated embodiments with reference to the accompanying drawings. The folded front door 138 is connected to close the front opening 134, and the rear door 140 is connected to close the rear opening 136. The front and rear doors 138, 140 in this embodiment include flat spring metal members, which are hinged to the front and rear openings 134, 136. The doors 138 and 140 are designed such that when the plug is inserted into the opening of the receiving cavity 132, these doors can be folded down into a flat shape. In this embodiment, the rear plate housing assembly 120 includes a molded plastic part of an insulating material, which can exhibit the structural strength and dimensional stability required to maintain the position of the optical fiber. These materials include (but are not limited to) thermoplastic cast-molded polymers with or without reinforcements, and transfermoldable polymers such as epoxy resins. polymers). The doors 138, 140 are made of conductive metal materials, such as tempered stainless steel, beryllium/copper alloy or other materials, and they are connected to provide a grounded circuit. The doors 138 and 140 have three functions: 1) Provide a practical barrier to restrict the entry of environmental pollutants into the assembled joint housing; 2) Realize absorption and transmission to ground electromagnetic interference, otherwise these electromagnetic interference will pass through the back plate The cavity 132 of 104 leaks; and 3) Provide eye protection to prevent light signals emitted from either end of the back plate.

The back plate housing assembly 120 may include mating features corresponding to a normal plug or ferrule. The double door design makes it possible to seal the optical connection without including a special door terminal at each joint. The dual door configuration also allows at least one door to be closed at any time when the receiving cavity is not filled by the rear and front plugs. Finally, the use of a conductive metal door held in the conductive housing assembly 124 allows the use of a relatively simple and sophisticated design to accommodate and ground EMI components. In embodiments where the user does not involve the above-mentioned problems, the use of these doors is optional, and they will not affect the performance and functions of the rear panel housing assembly 120.

Another useful feature of the housing assembly 120 is the use of side stop pin receiving features 142. When traditional plug retention features such as those in traditional telephone plugs are placed on top of the connector plug and the receiving housing, it can be found that such a configuration will unnecessarily interfere with the accumulation of ribbon-shaped flat fiber optic cables. The present invention solves this problem by arranging the stop pin receiving features along the same plane defined by the optical fiber array in an optical fiber ribbon cable. This allows multiple flat ribbon cables to be stacked vertically in a small space.

When the circuit board 102 slides into the guide slot 106, the front end of the rear board housing assembly 120 is mated with a circuit board housing assembly 150. The circuit board housing assembly includes a housing member 152 that includes a number of hollow protrusions 154 whose size is set to correspond to the front opening 134 of the rear board housing 120 and fit therein. The circuit board housing assembly 150 includes a circuit board connection feature 156 having a barbed end 158. The circuit board connection feature 156 is designed to be inserted through a receiving slot 160 in the flat base 102. When the circuit board connection feature 156 fixes the circuit board housing assembly to the circuit board in the lateral and lateral directions, a certain range of freedom of movement along the longitudinal axis is allowed. In this embodiment, the length of the slot 160 exceeds the width of the positioning feature 156. While allowing free movement in the x-direction, a person of ordinary skill in the art can easily think of other methods for connecting the circuit board housing assembly 150 to the flat substrate 102. Other embodiments may include connecting devices such as mechanical fasteners, spring clips, and the like.

The convex part 154 in this embodiment is hollow, and its shape is rectangular, and they end with a truncated pyramid-shaped front part 162. The pyramid-shaped front portion 162 allows to compensate for some misalignment by guiding the circuit board housing assembly protrusion 154 into the receiving cavity 132 of the rear board housing assembly. In addition, the shape of the convex portion 154 is set to achieve alignment with respect to the inner wall of the receiving cavity 132. The protrusion 154 can also provide an automatic pressure for opening the front door 138 during the mating process. The inner wall of the convex portion 154 forms a stepped cavity 164, and the cavity 164 provides a guide for the fiber optic ferrule 170 so that it can be seated in the stepped cavity 164. In this embodiment, the shape of the stepped cavity 164 is set to receive an industry standard ferrule such as an MT-type optical ferrule. The stepped cavity 164 is designed in such a way that it includes a front and a rear rectangular openings 166 and 168, respectively. The size of the front opening 166 is set to allow the ferrule 170 to be inserted upwardly into an inner flange 172. A typical MT-type connector includes a ferrule mounted on the shaft of the optical fiber 174, the ferrule and a buffer body part (detente body portion) 176 sliding connection. The ferrule 170 has a limited range of motion x1 along the longitudinal axis. The shaft of the optical fiber 174 is allowed to move relative to the buffer body portion 176. A spring part located between the ferrule and the buffer body portion deflects the ferrule forward toward the front end of the range of motion.

In this embodiment, the circuit board housing assembly 150 includes a number of rear openings 168 which are designed to receive an MT connector including a buffer body portion 176. The buffer body portion 176 remains abutted against the flange 173, and the ferrule 170 is allowed to extend upward inside the protrusion 154 and through the rear opening 168. The buffer member 176 is designed in such a way that the member 176 is inserted into the front end of the stepped cavity 164 and the spring is compressed between the buffer member 176 and the ferrule 170. The flange 180 formed in the ferrule 170 can prevent the ferrule 170 from freely running through the rear opening 168. The flange 180 is formed such that when the flange 180 is mated with the inner flange 172, the flange 180 can function as an operation stop of the ferrule 170. The buffer member 176 is provided with a pin-stop feature that can be matched with the rear opening 168 of the circuit board housing assembly 150. Preferably, the pin stop feature is provided on both sides of the housing assembly 150 and the cushioning member 176. In some cases it is desirable to be able to remove the cushioning member 176 from the housing assembly. For these cases, a release feature may be provided on the side of the housing. The release feature is cantilevered and allows it to pivot, thereby allowing the release feature to pop out, thereby releasing the corresponding detent feature.

The running length of the circuit board 102 along the circuit board guide 106 can be selected such that the circuit board housing assembly 150 can exert a spring force on the rear board housing assembly 120 when in the connecting position. In a preferred embodiment, the width of the circuit board gap should be greater than 0, and preferably should be greater than the combined stroke (usually 1 to 2 mm) of the spring-biased ferrules relative to their corresponding housings.

The operating range x2 of the circuit board housing assembly 150 relative to the circuit board 102 is sufficient to correct the allowable error in the movement range of the circuit board 102 along the circuit board guide 106, and may be provided in the rear board housing 120 or the circuit board guide 106 Before some stop features stop the circuit board, when the circuit board slides, the operating range x2 is sufficient to absorb any excessive force applied by the user. The present invention solves the problem of excessive compression by allowing the circuit board to be connected with joint parts that move relative to the circuit board. Therefore, in the connected position, the circuit board housing assembly 150 is held in close contact with the back of the rear board housing assembly 120, and is subjected to a constant spring bias provided by the spring assembly 184. The advantage of providing a constant spring bias is that even if the circuit board 102 moves during its operation, close contact can be ensured between the housing components 150 and 120.

FIG. 5 shows a detailed cut-away perspective view of the rear panel housing assembly 120 with front and rear doors 138,140. The door 138 is designed such that when the convex portion 154 of the circuit board housing assembly 150 is inserted into the front opening 134, the pyramid-shaped front portion 162 of the convex portion 154 forces the front door 138 to fold down. Similarly. When the plug 190 is inserted into the rear opening 136, the insertion of the plug 190 causes the rear door 140 to fold down. The doors 138 and 140 are preferably formed of an elastic material, which should withstand multiple cycles of being folded to an open position, and then restored to a closed position when the plug 190 or protrusion 154 is removed. In the case of EMI protection, the rear door 140 and the first part 124 of the rear panel housing may be composed of conductive materials such as metal. When the back door 140 and the first part 124 are made of conductive materials, they will absorb most of the EMI radiation that may escape through the cavity 132. Then, the first portion 124 is electrically connected to the ground terminal feature. In another embodiment, the door 140 or the first part of the back plate housing 122 may be made of an insulating material, leaving only one conductive part. The remaining conductive part should be grounded.

By providing the front door 138 and the rear door 140 covering the front opening 134 and the rear opening 136, the removal of the plug 190 or the circuit board housing assembly 150 will close one of the two doors, which can reduce any possible visual safety Hidden dangers. It should be understood that each door can function independently of the other door. Therefore, this means that if only one plug 190 is inserted into the rear opening 136, the rear door 140 holding the receiving cavity 132 will remain closed. To further ensure that the doors 138 and 140 can fit snugly in the openings 134 and 136, a number of frame features may be formed on the side walls of the receiving cavity 132 that match the side profile and overlap the side edges of the doors 138 and 1140 144. This feature can form a tighter seal to prevent contamination, maintain EMI, and prevent light leakage.

FIG. 14 shows a rear panel housing assembly 120 according to the present invention, which includes another embodiment of a folding front door 338 and a folding rear door 340. In this example, the structure of the folding front door 338 and the folding rear door 340 includes a pair of biasing members 342, 344 of substantially equal size, which pass through an elongated hinge plate located between the biasing members 342, 344 and integrally formed therewith. 346 are connected together. The overall appearance of each folding door 338, 340 is a V-shaped folded flat element, which includes a hinged plate 346 substantially in the middle. The opposite longitudinal edges of the hinged plate 346 are connected with biasing members 342, 344. The pressing members extend outward from these sides of the hinge plate 346.

After the biasing members 342, 344 of each folding door 338, 340 are installed in the housing assembly 120, they may open one of the front openings 134 or the rear openings 136 of a pair of adjacent receiving cavities 132 Provide closure at the place. In the embodiment shown in FIG. 14, the installation of the folding doors 338 and 340 requires the first stop pin 348 and the second stop pin 350 to be arranged adjacent to the longitudinal edge of each hinge plate 346. The stop pins 348 and 350 cooperate with an upper stop pin seat 352 and a lower stop pin seat 354, which are formed as recesses in the upper and lower surfaces of an intermediate wall 356 between adjacent receiving cavities 132. Using, for example, a hinge plate 346 aligned with the intermediate wall 356 and the biasing members 342, 344 positioned on the openings 134 of the adjacent pair of receiving cavities 132, and a stop pin 348 positioned to be mated with the stop pin seats 352, 354 , 350, the pressure applied to the hinge plate 346 connects the folding door 340 with the housing assembly 120. In this way, the connection between the folding door 340 and the intermediate wall 356 is realized by the interference fit between the stop pins 348 and 350 and the stop pin seats 352 and 354. When the plug 190 is inserted into or extracted from the receiving cavity 132, the fixed connection of the hinge plate 346 adjacent to the intermediate wall restricts the movement of the hinge plate 346, but allows the biasing members 342, 344 to deform independently of each other. The manufacture of the biasing members 342, 344 requires the use of a durable material that can maintain its shape, allowing it to cycle repeatedly between a retracted condition and a closed condition, where it can be It is allowed to pass into the receiving cavity 132, and in the closed condition, the biasing members 342, 344 can be filled into an opening 134, 136 to become a barrier to prevent contaminants such as dirt, dust, moisture and the like. Preferably, this durable material may be a flexible metal such as a stainless steel alloy, a beryllium/copper alloy or a similar elastic material, and this material can basically return to its original shape even after a deformation force is applied multiple times.

FIGS. 6 and 7 show the positioning of the spring 184 inserted into the spring receiving opening 186 and the housing assembly 150. The spring 184 is a wire spring, and the wire diameter is set so that the wire spring 184 can provide a slight pressure fit between the spring, the board connection feature 156, and the receiving circuit board slot 160. With the spring 184 inserted into the spring receiving opening 186, the circuit board connection feature 156 can be prevented from bending, thereby locking the housing assembly 150 and the circuit board 102. With particular reference to FIG. 6, one should understand how the slot 160 provides a passage through the circuit board 102 for the circuit board connection feature 156. The barbed end 158 of the circuit board connection feature 156 is designed to grip the back side of the plug-in board 102, thereby fixing the housing assembly 150 to the daughter board 102 along the transverse axis. The size of the slot 160 is set such that the circuit board housing assembly 150 has a movement range x2 along the longitudinal axis on the surface of the circuit board 102. The combination of the forward deflection of the spring assembly 182 and the degree of freedom x2 of the movement of the housing assembly 150 makes it possible to compensate for errors in the alignment of the circuit board 102 with respect to the rear board 104. The combined force of the spring 184 of the spring assembly 182 is selected to be greater than the sum of all relative spring forces such as those of the individual springs 178 of the individual ferrule assembly. Otherwise, the coupling force of the spring 178 of the ferrule assembly will push the housing assembly backward, thereby preventing the required connection between the circuit board housing assembly 150 and the rear plate housing assembly 120. However, since the forward movement of the circuit board housing assembly 150 will be restricted by the flange 151, the individual ferrules will still maintain their range of movement, thereby ensuring a tight fit on each individual fiber connection.

As shown in FIGS. 6 and 7, the longitudinal movement of the circuit board housing assembly 150 is controlled by the spring assembly 182. The term "spring" refers to a returnable or elastic member, such as a coil spring, a biasing clip, an elastic band, a compressed foam material, or other similar devices known in the art. In this embodiment, the spring assembly 182 includes two spring clips 184 that are laterally spaced apart from each other, and they are basically located at the lateral ends of the circuit board housing assembly 150. The spring assembly 182 can perform three functions: (a) Apply a forward force along the longitudinal axis on the circuit board housing assembly 150, thereby connecting the circuit board housing assembly 150 and the circuit board on which the circuit board housing assembly 150 is installed. A spring bias is formed between 102; (b) the circuit board locking feature 156 is locked, thereby preventing the circuit board housing assembly 150 from being unintentionally removed from the circuit board; and (c) providing compensation for the angular misalignment of the circuit board.

The spring assembly 182 preferably biases the circuit board housing assembly 150 toward the front or mating edge of the daughter board, so that when the circuit board housing assembly 150 moves by a force opposite to the normal force of the spring 184 , Forcing the circuit board housing assembly 150 to move against the resistance of the spring 184.

In addition, as shown in FIG. 8, the two springs 184 (see FIG. 7) at laterally spaced apart positions allow correction of angular misalignment, thereby reducing the pressure on the front edge of the rear plate housing assembly 150 and possible Damage, and can compensate for the angular misalignment of the hole.

Figures 9-11 show the plug assembly 190. The plug assembly 190 is designed to receive a conventional MT-type connector ferrule and provides connection features that can mate with the back plate housing assembly 120. It is easily understood by those skilled in the art that the plug assembly can be molded to accept different types of connectors. In another embodiment of the present invention, the shape of the back plate housing assembly can be designed to directly receive a traditional joint assembly.

The plug assembly 190 is composed of a lower housing member 192 and a housing cover 194. As mentioned above, an MT-type joint assembly includes a collar 170 and a collar spring 178. The MT type connector is used to terminate a multi-fiber ribbon cable 196 surrounded by a protective sheath 198.

The lower housing assembly 192 includes a front opening 200 defined by the flange surface 202, a receiving recess 204, and a retaining spring lip 206. The ferrule 170 has a front portion 171 and a flange 172. The front part 171 passes through the opening 200. However, the size of the opening 200 is set such that the flange 172 is too large to pass through the opening 200 and the flange 172 abuts the flange surface 202. When the end 179 of the ferrule spring 178 is properly placed in the lower housing 192, as shown in FIG. 10, it rests in the receiving recess 204 and is compressed between the flange 172 and the retaining spring lip 206 . The compression of the ferrule spring 178 generates a force applied against the flange 172 and the lip 206, wherein the spring biases the ferrule 170 forward through the opening 200.

FIG. 11 shows the housing cover 194 positioned to connect to the lower housing 192. This connection can be conveniently achieved by placing the mating feature 208 of the housing cover 194 in the engagement cavity 210 present in the side wall of the lower housing part 192. When the housing cover 194 is rotated downward, the mating feature 208 may be embedded in the mating cavity 210. As the rotation progresses, the male snap stop pin 212 can cooperate with the corresponding female stop pin receiving feature 214 to lock the lower housing part 192 and the housing cover together.

An opening 216 is provided in the lower housing part 192 to provide a path for the reinforcement member 218 to pass through. The strengthening member 218 is generally present in the optical fiber cable, and is usually connected to the housing of the optical fiber connector to relieve the axial stress on the optical fiber of the cable.

The lower housing part 192 also includes a number of cavities 220, and the posts 222 of the housing cover 194 can be inserted during the assembly process, so that the housing cover 194 and the lower housing member 192 are laterally aligned and locked.

FIG. 12 shows the plug assembly 190 assembled on the optical cable 196, and the cable is equipped with a bending radius control member 230. The bending radius control member 230 that can achieve the purpose described here is composed of shrinkable pipes, and these shrinkable pipes are applied to the rear housing part 232 of the plug assembly 190, the cable protective sleeve 198, and the cable reinforcing member 182 on. The bending radius control member 230 is heated and contracted into a position where the cable 196 and the plug 190 are fixed.

FIG. 13 shows a cable forming device 250 which includes a vertical support 252 fastened to the base plate 254 and one or more forming mandrels 256 connected to the vertical support 252. The radius of the mandrel 256 exceeds the critical bending radius of the optical cable 196. The angle between the mandrels 256 corresponds to the desired path of the optical cable 196.

To apply the bending radius control member 230, the retractable tube or sheath 262 first slides or surrounds the plug assembly 190 and the optical cable 196. The term "heat-shrinkable sheath or tube material" includes tubes, sheaths, tapes, wraps, or covers made of heat-shrinkable materials, which can be wrapped on the desired part of the optical cable. The term "heat-shrinkable sheath" refers to a material that when it is heated, it collapses and shrinks around the optical cable, and when it returns to ambient temperature, it can maintain this collapsed shape. This material Such as heat-shrinkable plastic.

The cable 196 and the shrinkable tube wrap around the mandrel 256. The device 250 shown produces a double bend in which the cable 196 is shaped downwards and to the left, thereby creating a combined bend. Then, the shrinkable tube material is heated to a temperature sufficient to cause the tube to shrink. In this embodiment, the heat radiation required to collapse the heat-shrinkable material is selected to avoid any harmful effects on the optical cable, but is higher than the normal operating range of the optical cable. The heat source may include a high temperature air gun, a heat emitting element, a heating mandrel, or other suitable heat sources. The heating can be done before or after placing the fiber optic cable 196 on the mandrel 256. While the tube is cooling, the shrinkable tube 262 and cable 196 remain wrapped around the mandrel 256. Once cooled, the cable 196 will acquire the desired shape and bend radius. The hardness of the formed cable will be controlled by the thickness and hardness of the material forming the shrinkable tube.

In some cases, heat-activated adhesives may be applied to the inner surface of the shrinkable tube. These adhesives may form a protective cover with the optical cable 196 and a bond with the rear housing portion 232. The bending radius control member can be applied to any part of the cable that needs to be bent. Workshop applications can be carried out using wrapable shrink materials and portable heat sources, such as high-temperature air guns or lamps.

It should be pointed out that the present invention is not limited to the use of shrinkable pipes to achieve strain relief and bending radius control. However, the use of shrinkable pipes can provide a low-cost solution, thereby avoiding the problem of high costs.

Those of ordinary skill in the art can understand that the present invention can be used when precise alignment is required to connect various optical devices or even non-optical devices. Although the present invention is described with reference to the preferred embodiments, the present invention can also be embodied in other special forms without departing from the spirit of the invention. Therefore, it should be understood that the embodiments described and illustrated herein are only exemplary and should not be regarded as limiting the scope of the present invention. Other changes and improvements can be made in accordance with the spirit and scope of the present invention.