Ultraviolet light monitoring system for a fiber curing system

Abstract

System (100) for monitoring fiber hardening, comprising: an elliptical reflecting chamber (302, 303) comprising at least two light-sensing apertures (320, 321); at least two light sources (112, 113), each of the at least two light sources (112, 113) being directed towards a curing tube (126), the curing tube (126) being positioned between the at least two light sources (112, 113) and in at least one section of the elliptical reflecting chamber (302, 303); and a light receiver (155, 156) which is in optical contact with the at least two light detection apertures (320, 321).

Description

BACKGROUND / SUMMARY

[0001] Optical fibers can be used to transmit light from an emitting source to a receiver. The light source can convey data in emitted light to support communication between two ends of the optical fibers. The optical fibers can be protected from scratches and abrasion by a coating covering the length of the optical fiber. The protective coating can be cured by exposure to a specific wavelength of light energy. In one example, the coating cures when exposed to ultraviolet (UV) light. The time required to cure the coating can depend on the light intensity and the length of time the coating is exposed to the light.If the light intensity intended for the optical fiber and its coating is greater than a target light intensity, the lighting system may consume too much power, and the lighting system cooling may not be sufficient to cool the light source. If the light intensity intended for the optical fiber and its coating is lower than a target light intensity, the optical fiber coating may not cure as desired.

[0002] A system for curing coatings on optical fibers is described in US Patent No. 5,418,369. It includes an elliptical reflective chamber, a UV bulb, and two UV detectors positioned outside the elliptical reflective chamber. The first UV sensor monitors the amount of light emitted by the UV lamp, the second UV sensor monitors light passing through a curing tube, and an average of the light bypassing the curing tube is described. However, the elliptical reflective chamber and bulb described in US Patent No. 5,418,369 may not be as efficient as desired, and some of the light exiting the elliptical reflective chamber may not reach the UV sensor because the UV sensor is positioned remotely from the elliptical reflective chamber. Further prior art is known from JP S63- 277 538 A, JP 2003- 131 090 A and US 2013 / 0 068 969 A1.

[0003] The present inventor has recognized the above-mentioned problems and developed a system for monitoring fiber curing, comprising: an elliptical reflective chamber including at least two light detecting apertures; at least two light sources, each of the at least two light sources directed toward a curing tube, the curing tube positioned between the at least two light sources and in at least a portion of the elliptical reflective chamber; and a light receiver in optical communication with the at least two light detecting apertures.

[0004] By detecting light from two light sources directed onto a curing tube in an elliptical reflection chamber, it may be possible to combine light energy from two or more locations around the circumference of the elliptical reflection chamber to determine an average amount of light energy directed onto the curing tube. Furthermore, the two light-detecting apertures may accommodate optical fibers that begin flush with the elliptical chamber wall, so that light striking the optical fiber is detected rather than being able to exit the elliptical chamber without reaching a photodetector. This eliminates the need for a light receiver to be in a clear line of sight to the light source.Furthermore, the elliptical reflection chamber can be configured so that all sides of a fiber being cured receive similar amounts of light energy, so that the fiber cures more evenly and so that the curing system uses less energy to cure a coating applied to the fiber.

[0005] The present description may offer several advantages. In particular, the method may provide improved estimation of the average light energy delivered to a fiber curing chamber. Furthermore, the method may be useful for controlling fiber curing system operation and indicating whether or not light source degradation is present. Furthermore, the method may also provide light energy monitoring for a more energy-efficient fiber curing system.

[0006] The foregoing advantages and other advantages and features of the present description will be readily apparent from the following detailed description taken alone or in conjunction with the accompanying drawings.

[0007] It should be understood that the foregoing summary is provided to introduce, in a simplified form, a selection of concepts that are further described in the detailed description. It is not intended to identify crucial or essential features of the claimed subject matter, the scope of which is determined solely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE CHARACTERS Fig. Figure 1 shows a schematic representation of a fiber curing system; Fig. Figure 2 shows a schematic diagram of exemplary fiber curing system subsystems; Fig. 3A shows an exemplary cross-section of a fiber curing system illustrating light energy capture apertures; Fig. Figure 3B shows an exemplary longitudinal cross-section of a fiber curing system illustrating light energy capture apertures; Fig. Figure 4 shows an exemplary cross-section of a fiber curing system illustrating devices that determine the transparency of the curing tube; Fig. 5 shows an exemplary method for determining the light energy emitted by a fiber curing system; and Fig. Figure 6 shows an exemplary method for determining cure tube transparency or light transmission for a fiber curing system. Fig. 3A, Fig. 3B and Fig. 4 are shown approximately to scale. DETAILED DESCRIPTION

[0008] The present description relates to a fiber curing system for curing a coating applied to a fiber. Fig. Figure 1 shows an exemplary fiber curing system that includes an elliptical reflective chamber that focuses light toward a coated chamber. Energy from the light delivered into the elliptical reflective chamber is used to cure the coating applied to the fiber. The fiber curing system can be configured as shown in Fig. 2. Light energy in the elliptical reflecting chamber can be captured by means of light capture apertures, as shown in Fig. 3. The transparency and / or light transmission of a curing tube in the fiber curing system can be determined by means of devices as shown in Fig. 4 is shown. In Fig. 5 describes a method for determining the amount of light energy emitted by a fiber curing system. Finally, Fig. 6 describes a method for determining transparency or translucency of a curing tube.

[0009] With reference now to Fig. Figure 1 shows a schematic representation of a fiber curing system. In this example, the fiber curing system is used to cure a fiber protective coating applied to a single fiber. However, in other examples, the fiber curing system may be in a form that cures a coating applied to multiple fibers arranged in a ribbon. Furthermore, the systems and methods described herein may be applicable to fiber curing systems with other configurations.

[0010] A liquid-coated fiber 175 is pulled through a body 133 and a curing tube 126 during operation of the fiber curing system 100. The curing tube 126 may be formed of fused silica or another material that allows light to pass through the curing tube 126. Light energy is directed onto the fiber 175 in an elliptical reflective chamber (not shown) within the body 133. The light energy cures the protective coating, forming a solid protective layer over the fiber 175. During the curing process, vapors may be emitted from the protective coating as it cures. The vapor may condense on the inside of the curing tube 126, reducing the light transmission of the curing tube 126 and decreasing the efficiency of the fiber curing system 100. Inert gas, such as nitrogen (N2), may flow through the curing tube 126 to remove vapors from the curing tube 126.However, precipitates may form on the curing tube 126 even if inert gas flows through the curing tube 126.

[0011] The fiber curing system 100 includes a body 133 containing elliptical reflective chambers (not shown). The body 133 may consist of multiple sections coupled together. A first light source 112 and a second light source 113 are coupled to the body 133 and arranged longitudinally with a long axis 170. The first light source 112 directs light into the body 133 and in a direction toward the second light source 113. The second light source 113 similarly directs light into the body 133 and in a direction toward the first light source 112. Thus, both the first light source 112 and the second light source 113 direct light energy toward the curing tube 126. The first light source 112 and the second light source 113 may be cooled by a liquid coolant supplied from a cooling device (not shown) via coolant lines 130.

[0012] A third light source 122 and a fourth light source 123 provide light used to determine the transparency and / or translucency of the curing tube 126. Light detectors or receivers are positioned on a side of the body 133 opposite the side 105 to receive light from the third light source 122 and the fourth light source 123. Note that while the present example includes two light sources and receivers for determining transparency and / or translucency of the curing tube 126, another example may include 1 to N light sources and receivers for determining transparency and / or translucency of the curing tube 126. Optical fibers 114 and 115 are also coupled to the body 133.

[0013] The first light source 112 and the second light source 113 may include multiple light-emitting arrays. In one example, each light-emitting array includes multiple light-emitting diodes (LEDs). The light-emitting arrays may be arranged in a column along the long axis 170. For example, the first light source 112 and the second light source 113 may include three light-emitting arrays arranged in a single column comprising three rows, the column being formed in the direction of the long axis 170. In other examples, the first 112 and second 113 light sources may be configured with different numbers of rows and columns of light-emitting arrays. The light-emitting arrays direct light energy toward the fiber 175 inside the body 133.

[0014] Left optical fibers 114 and right optical fibers 115 transmit light energy emitted by the first light source 112 and the second light source 113 to a plurality of photodetectors 155. Alternatively, left optical fibers 114 and right optical fibers 115 may be grouped together and input to a single photodetector 156. Left optical fibers 114 enter the body 133 in a columnar arrangement between the first light source 112 and the curing tube 126. Right optical fibers 115 enter the body 133 in a columnar arrangement between the second light source 113 and the curing tube 126. In one example, one optical fiber is provided for each light array in the first light source 112 and the second light source 113. Each right optical fiber 115 is positioned at an equal distance between adjacent right optical fibers 115.Each left optical fiber 114 is similarly positioned at the same distance between adjacent left optical fibers 114.

[0015] In one example, the third light source 122 and the fourth light source 123 consist of collimated light sources, for example, laser light. The collimated light source can reduce the amount of light not directed to a corresponding light receiver, so that the signal-to-noise ratio for detecting a blocked curing tube, partially blocked curing tube, or a curing tube with reduced light transmission can be improved.

[0016] Fig. 1 also shows the positions of cross sections AA, BB and CC. Cross section AA is in Fig. 4, cross section BB is in Fig. 3A, cross section CC is shown in Fig. 3B. Cross section AA shows details of the curing tube's transparency and / or translucency system. Cross section BB shows details of a portion of the UV power monitoring system. Cross section CC shows a longitudinal view of a portion of the UV power monitoring system.

[0017] With reference to Fig. Figure 2 shows a schematic diagram of the fiber curing system subsystems. The fiber curing system 100 includes an illumination subsystem 200, a coolant subsystem 202, and an inert gas subsystem 204.

[0018] The lighting system 200 includes one or more light-emitting devices 210 in thermal communication with a heat sink 231. In this example, the light-emitting devices 210 are light-emitting diodes (LEDs). Each LED 210 includes an anode 220 and a cathode 222. A switching power source (not shown) supplies 48V DC to a voltage regulator 240 via a path or conductor 264. The voltage regulator 240 supplies DC to the anodes 220 of the LEDs 210 via conductor or path 242. The voltage regulator 240 is also electrically connected to cathodes 222 of the LEDs 210 via a conductor or path 244. The voltage regulator 240 is shown with reference to ground 260 and, in one example, may be a buck regulator.

[0019] The controller 208 is shown in electrical communication with the voltage regulator 240. In other examples, discrete input-generating devices (e.g., switches) may be substituted for the controller 208 if desired. The controller 208 includes a central processing unit (CPU) 290 for executing instructions. The controller 208 also includes inputs and outputs (I / O) 288 for operating the voltage regulator 240, communicating with an external controller 228, and operating other devices. A read-only memory 292 may store non-volatile executable instructions, while a random access memory 294 may store variables. The voltage regulator 240 supplies an adjustable voltage and current to the LEDs 210. The controller 208 may provide control signals to the voltage regulator 240 to adjust the output voltage of the voltage regulator.The controller 208 may also receive input from the optical fibers 114 and 115 via the photodetectors 155.

[0020] A switching device or variable resistor 280 in the form of a field-effect transistor (FET) receives an intensity signal voltage from the controller 208 or via another input device. While the present example describes the variable resistor as a FET, it should be noted that the circuit may utilize other forms of variable resistors. By adjusting a control signal to the variable resistor 280, the controller 208 adjusts the current flow through the LEDs 201 and the light intensity produced by the LEDs 210.

[0021] In this example, at least one element of the illumination array 271 comprises solid-state light-emitting elements such as light-emitting diodes (LEDs) or laser diodes that generate light. The elements can be configured as a single array on a carrier, multiple arrays on a carrier, multiple arrays either individually or multiple on multiple interconnected carriers, etc. Although in Fig. 2 only a single LED array is shown, the first light source 112 and the second light source 113 can be Fig. 1 may comprise one or more light arrays as shown. Each array 271 in the first and second light sources may be powered by a single voltage regulator 240 so that all light arrays receive the same amount of power. Alternatively, each light array 271 in the first and second light sources may be powered by its own dedicated voltage regulator 240 so that different amounts of electrical power may be supplied to each light array 271 simultaneously. In this way, the amount of electrical power supplied to each light array 271 may be adjusted without adjusting the electrical power to other light arrays. Similarly, the illuminance of each light array 271 may be adjusted without adjusting the illuminance of other light arrays in the fiber curing system 100.

[0022] The Fig. The lighting system circuit shown in Figure 2 is a closed current control loop. Variable resistor 280 receives a magnitude voltage control signal via conductor or path 230 through drive circuit 222. Variable resistor 280 receives its control signal from driver 222. The voltage between variable resistor 280 and array 271 is controlled to a desired voltage determined by voltage regulator 240. The desired voltage value may be provided by controller 108 or another device, and voltage regulator 240 controls voltage signal 242 to a value that provides the desired voltage in a current path between array 271 and variable resistor 280. Variable resistor 280 controls the current flow from array 271 to current sensing resistor 255 in the direction of arrow 245.

[0023] The target voltage can also be adjusted in response to the type of lighting device, the type of working fiber, curing parameters, and various other operating parameters. An electrical current signal can be passed back along conductor or path 236 to the controller 208 or other device that adjusts the intended intensity voltage control signal. In particular, if the electrical current signal differs from a desired electrical current, the intensity voltage control signal passed via conductor 230 is increased or decreased to adjust the electrical current through the array 271. A current feedback signal indicating electrical current flow through the array 271 is passed via conductor 236. The current feedback signal is a voltage value that changes as the electrical current flowing through the current sensing resistor 255 changes.

[0024] In addition, the controller 208 can adjust the light intensity control signal in the conductor 230 to increase or decrease the intensity of light emitted by the array 271 based on light detected from the optical fibers 114 and 115 by the photodetector 155. In one example, the light intensity of multiple arrays 271 is adjusted to a same value by the controller 208 in response to input from multiple optical fibers 114 and 115, as in the fiber curing system 100 of Fig. 1. In other examples, the light intensity of each array 271 is individually adjusted in response to the optical fiber 114 / 115 receiving light from a selected array 271. For example, in one shown in Fig. 1, which comprises three light arrays and three optical fibers that detect light emitted by the three arrays, the light intensity of a first array is adjusted in response to light detected by a first optical fiber, the light intensity of a second array is adjusted in response to light detected by a second optical fiber that is different from the first optical fiber, etc.

[0025] The controller 208 may also increase the resistance of the variable resistor 280 to operate it as a switch and stop current flow through LEDs 210. Further, the controller 208 may, according to the methods of Fig. 5 and Fig. 6 work to adjust the light intensity emitted by LEDs 210.

[0026] In an example where the voltage between variable resistor 280 and array 271 is set to a constant voltage, the current flow through array 271 and variable resistor 280 is adjusted by adjusting the resistance of variable resistor 280. Thus, a voltage signal carried along conductor 244 from variable resistor 280 does not reach array 271 in this example. Instead, the voltage feedback between array 271 and variable resistor 280 follows conductor 244 and goes to voltage regulator 240. Voltage regulator 240 then outputs a voltage signal 242 to array 271. Consequently, voltage regulator 240 adjusts its output voltage in response to a voltage downstream of array 271, and the current flow through array 271 is adjusted by means of variable resistor 280.Controller 208 may include commands for adjusting a resistance value of variable resistor 280 in response to an array current fed back as a voltage via conductor 236. Conductor 244 provides electrical connection between the cathodes 222 of LEDs 210, an input 299 (e.g., a drain of an N-channel MOSFET) of variable resistor 280, and the voltage feedback input 293 of voltage regulator 240. Thus, the cathodes 222 of LEDs 210, an input side 299 of variable resistor 280, and the voltage feedback input 293 have the same voltage potential.

[0027] The variable resistor can take the form of a FET, a bipolar transistor, a digital potentiometer, or any electrically controllable current-limiting device. Alternatively, a manually controllable current-limiting device can be used as a variable resistor. The drive circuit can take different forms depending on the variable resistor used.

[0028] The heat sink 231 can be air- or liquid-cooled. In this example, the heat sink 231 is liquid-cooled using coolant flowing from the cooling device 249 via a coolant pump 264 and a coolant flow control valve 265. The controller 208 can adjust the coolant flow rate to the heat sink 231 in response to an amount of electrical power delivered to the LEDs 210. For example, if the power delivered to the LEDs 210 is increased, the coolant flow rate from the cooling device 249 to the heat sink 231 can be increased by increasing the coolant pump power and / or the amount of opening of the coolant valve 265. Similarly, if the power supplied to the LEDs 210 is reduced, the coolant flow rate from the cooling device 249 to the heat sink 231 can be reduced by reducing the coolant pump power and / or the opening amount of the coolant valve 265.Alternatively, the control unit 208 may provide an indication to an external control unit to adjust the coolant flow rate.

[0029] In this example, the inert gas subsystem 204 includes an external controller 228, a gas pump 226, a gas control valve 225, a gas scrubber or filter 224, and a gas storage vessel 223. The positions of the gas pump 226, the gas control valve 225, the filter 224, and the gas storage vessel 223 can be rearranged as needed.

[0030] The controller 208 can communicate with the external controller 228 to increase or decrease an amount of inert gas flowing through the curing tube 126. In one example, the external controller 228 increases the power of the gas pump 226 and opens the gas valve 225 in response to a transparency or translucency of the curing tube 126 decreasing at a rate greater than desired to increase the life of the curing tube. Alternatively, the external controller decreases the power of the gas pump 226 and closes the gas valve 225 in response to a transparency or translucency of the curing tube 126 decreasing at a rate less than desired to reduce gas usage.

[0031] Additionally, controller 208 may communicate the degradation rate of the transparency or translucency to external controller 228 so that external controller 228 can adjust the amount of coating applied to fiber 175. The signal-to-noise ratio of the curing tube transparency and / or translucency provided by collimated light sources 122 and 123 may be sufficient to provide estimates of the curing tube transparency and / or translucency that indicate more than degraded / not degraded.

[0032] With reference now to Fig. Figure 3A shows a cross-section of the light energy detection apertures for a UV power monitoring and control system. Fig. 3A is the Fig. 1 shown cross section BB.

[0033] The body 133 includes a first elliptical reflective chamber 302 and a second elliptical reflective chamber 303 for concentrating light emitted from the first light source 112 and the second light source 113 onto the fiber 175. The first elliptical reflective chamber 302 has a center position 370. The second elliptical reflective chamber 303 has a center position 371. LEDs of the first light source 112 are positioned along a plane passing through a first focal point of the first elliptical reflective chamber 302, and LEDs direct light in a direction shown by arrow 330. LEDs of the second light source 113 are positioned along a plane passing through a first focal point of the second elliptical reflective chamber 303, and LEDs direct light in a direction shown by arrow 331.Light from the first light source 112 and the second light source 113 converges at 310, which is a second focal point for both the first elliptical reflecting chamber 302 and the second elliptical reflecting chamber 303, as well as the center of the body 133. Centers of the fiber 175 and the curing tube 126 are positioned at 310 such that the lengths of the fiber 175 and the curing tube 126 are exposed to light throughout the length of the body 133. Such an arrangement focuses light from the first light source 112 and the second light source 113 at the fiber 175.

[0034] Optical fibers 114 enter body 133 through light-detecting apertures 320. Optical fibers 115 enter body 133 through light-detecting apertures 321. Light-detecting apertures 320 and 321 are positioned between centers 370 and 371 in a region of the periphery of first elliptical reflecting chamber 302 and second elliptical reflecting chamber 303 where light is collimated and representative of the light energy reaching fiber 175. Optical fibers 114 and 115 end or begin flush with first elliptical reflecting chamber 302 and second elliptical reflecting chamber 303.

[0035] The third light source 122 and the photodetector 360 for determining transparency or translucency (the ability of a material to allow incident radiation to pass completely through the material) are also shown.

[0036] With reference now to Fig. Figure 3B shows a cross-section of the light energy detection apertures for a UV power monitoring and control system. Fig. 3B is a Fig. 1 shown cross section CC and the CC cross section runs longitudinally with the body 133.

[0037] The optical fibers 115 are positioned along the length of the body 133, and the distances between the optical fibers 357 and 358 are substantially equivalent (e.g., ± 3.5 mm). The second light source 113 also extends along the length of the body 133. A top surface of the second elliptical reflective chamber 303 is also shown extending along the length of the body 133.

[0038] With reference now to Fig. Figure 4 shows a cross-section of a monitoring and control system for the transparency and / or translucency of the curing tube. Fig. 4 is the Fig. 1 shown cross section AA. The cross section of Fig. 4 includes many of the cross-sections of Fig. 3A, and the elements that are the same are identified by the same numerical designations. Therefore, for the sake of brevity, a description of elements already described is omitted.

[0039] The third light source 122 is positioned offset from the second focal point 310 of the first elliptical reflecting chamber 302 and the second elliptical reflecting chamber 303. By offsetting the third light source 122, light from the third light source 122 can pass through the curing tube 126 without striking or impinging on the fiber 175. A centerline 415 of the third light source 122 is shown offset from the fiber 175. A similar arrangement applies to the fourth light source 123 and fiber 175.

[0040] In one example, the third light source 122 is a source of collimated light, such as a laser. Light comes from the third light source 122 and passes through the transmissive light aperture 440 of the curing tube before reaching the curing tube 126. Light that makes it through the curing tube 126 can reach the receiver or photodetector 360, where a voltage or current proportional to the light power (e.g., watts / m 2 ) is output from the photodetector 360. Light from the third light source 122 can pass through the transparency detection opening 441 of the curing tube before reaching the photodetector 360.

[0041] If the curing tube 126 is relatively transparent, a larger amount of light provided by the third light source can be received by the photodetector 360. If the curing tube 126 is covered or partially covered with material, a smaller amount of light provided by the third light source can be received by the photodetector 360. If the curing tube 126 blocks more than a desired amount of light from the third light source, the curing tube 126 can be replaced with a new curing tube.

[0042] Thus, the system of Fig. 1-4 proposes a system for monitoring fiber curing, comprising: an elliptical reflective chamber including at least two light-detecting apertures; two light sources, each of the two light sources directed toward a curing tube, the curing tube positioned between the two light sources and in at least a portion of the elliptical reflective chamber; and a light receiver in optical communication with the at least two light-detecting apertures. The system further comprises a controller including executable instructions stored in non-volatile memory for indicating degradation of the two light sources. The system comprises the light receiver being coupled to the at least two light-detecting apertures by at least two optical fibers.

[0043] In some examples, the system includes a first of the at least two light sensing apertures positioned between a first of the two light sources and the curing tube, and the second of the at least two light sensing apertures positioned between a second of the two light sources and the curing tube. The system includes a first of the two light sources consisting of a plurality of LED arrays arranged in a first column, and the second of the two light sources consisting of a plurality of LED arrays arranged in a second column. The system also includes the elliptical reflective chamber further comprising light sensing apertures for each LED array in the first and second columns. The system includes the first column and the second column being arranged along a long axis of the curing tube.The system further includes a controller including executable instructions stored in non-volatile memory for indicating a desire to reduce, but not stop, fiber throughput for a fiber UV curing system.

[0044] The system of Fig. 1-4 also provides a system for monitoring and controlling fiber curing, comprising: a dual elliptical reflective chamber including first and second light detection apertures, the first light detection aperture being positioned in a first elliptical reflective chamber of the dual elliptical reflective chamber, the second light detection aperture being positioned in a second elliptical reflective chamber of the dual elliptical reflective chamber; two light sources, each of the two light sources being directed toward a curing tube, the curing tube being positioned between the two light sources and in at least a portion of the elliptical reflective chamber; and two light receivers in optical communication with the at least two light detection apertures.

[0045] The system includes the first and second light-detecting apertures being arranged longitudinally along a length of the curing tube. The system further includes third, fourth, fifth, and sixth light-detecting apertures contained within the dual elliptical reflective chamber, the first, third, and fifth light-detecting apertures being arranged along a long axis of the curing tube, and the second, fourth, and sixth light-detecting apertures being arranged along a long axis of the curing tube. The system includes the first, third, and fifth light-detecting apertures being arranged on an opposite side of the curing tube from the second, fourth, and sixth light-detecting apertures.The system further includes a third optical receiver coupled to the third light-detecting aperture, a fourth optical receiver coupled to the fourth light-detecting aperture, a fifth optical receiver coupled to the fifth light-detecting aperture, and a sixth optical receiver coupled to the sixth light-detecting aperture. The system further includes a controller including executable instructions stored in non-volatile memory for adjusting the output of the two light sources in response to output from the first, second, third, fourth, fifth, and sixth optical receivers.

[0046] With reference now to Fig. 5 shows a method for determining light energy output from a fiber curing system. The method of Fig. 5 can be stored in a non-volatile memory as executable instructions for a control unit, such as the one in Fig. 2 shown control unit 208. The method of Fig. 5 may be part of the Fig. 1-4 shown system.

[0047] At 502, method 500 determines whether or not to activate a fiber curing system. The fiber curing system may be activated in response to an operator or controller input. If method 500 determines to activate the fiber curing system, method 500 proceeds to 504. Otherwise, method 500 ends.

[0048] At 504, the method 500 activates two light sources (e.g., 112 and 113 of Fig. 1) on two opposite sides of the two elliptical reflective chambers. In one example, the light sources consist of one or more illumination device arrays. The arrays can be supplied with electrical power according to an illumination profile based on a position of each illumination array in the respective light sources. In one example, the illumination profile provides an equal amount of electrical power to the array in the respective light sources. In other examples, each array can be supplied with a unique amount of electrical power based on a position of the array in the light source according to the illumination profile.

[0049] For example, a lighting profile may specify that a light source with lighting arrays organized in a single column with three rows provides X watts to the lighting array at position (1,1) (e.g., (rows, columns)), X+5 watts to the lighting array at position (2,1), and X+10 watts to the lighting array at position (3,1). Each of the light arrays can be controlled by a system as described in Fig. 2. By adjusting each light array according to an illumination profile, it may be possible to influence the curing rate of the fiber coating along the length of the fiber curing system. By controlling the amount of electrical power delivered to each array, it may further be possible to compensate for illumination arrays that output more or less energy than desired by adjusting the power delivered to illumination arrays adjacent to degraded illumination arrays that receive more or less electrical power than desired. Method 500 proceeds to 506 after activating the two light sources.

[0050] At 506, the method 500 receives a portion of the light emitted by the two illumination sources at the inner surfaces of two elliptical reflective chambers. As in Fig. 3A, Fig. 3B and Fig. 4, optical fibers receive light from inside the first elliptical reflecting chamber 302 and the second elliptical reflecting chamber 303. The optical fibers may enter the elliptical reflecting chambers at positions between the centers of the two elliptical reflecting chambers, as shown in Fig. 3A and Fig. 3B. The optical fibers may all be input to a single photodetector. Alternatively, the optical fibers may each be input to a single photodetector that accommodates only one optical fiber. Method 500 proceeds to 508 after a portion of the light from the two light sources has been received.

[0051] At 508, method 500 decides whether or not to determine an average light intensity in the first and second elliptical reflective chambers. In some examples, it may be desirable to signal to an operator or controller when the average light intensity is less than a threshold light intensity. In other examples, the average light intensity may not be determined to save computation time or because it is not currently desired. If method 500 decides to determine the average light intensity in the two elliptical reflective chambers, the answer is yes, and method 500 proceeds to 510. Otherwise, the answer is no, and method 500 proceeds to 518.

[0052] At 510, method 500 adds the light intensity from multiple positions in the two elliptical reflective chambers. In an example where optical fibers are bundled together and input to a single photodetector, the photodetector outputs a sum of light energy from each position in the two elliptical reflective chambers where light is detected. The output from the photodetector can be sampled and averaged over a fixed period of time or a number of data sets to determine the average light intensity in the two elliptical reflective chambers.

[0053] In examples where multiple optical fibers are individually input to multiple photodetectors receiving input from a single optical fiber, the output of each photodetector may be added to the output of all other photodetectors and averaged over time or a number of data sets to determine the average light intensity in the two elliptical reflective chambers. Method 500 proceeds to 512 after determining the average light intensity in the two elliptical reflective chambers.

[0054] At 512, method 500 determines whether the average luminous intensity in the two elliptical reflection chambers is less than a first threshold luminous intensity value or greater than a second threshold luminous intensity value. The first and second threshold luminous intensity values ​​may vary depending on fiber coating, ambient temperature, and other conditions. If method 500 determines that the average luminous intensity in the two elliptical reflection chambers is less than a first threshold luminous intensity value or greater than a second threshold luminous intensity value, the answer is yes, and method 500 proceeds to 514. Otherwise, the answer is no, and method 500 proceeds to 518.

[0055] At 514, method 500 indicates degradation of the fiber curing system. The indication of degradation may be the illumination of a light, the sending of a message to an external control device that changes fiber processing, or the setting of a bit in memory. In some examples, a degradation condition may be indicated more than once before taking action such as reporting to an operator or external control device. For example, a degraded illuminance value might be observed three times before degradation is indicated. Further, adjustments to the electrical power supplied to the illumination arrays may be attempted to bring the average illuminance in the two elliptical reflection chambers to a desired value before degradation is indicated to an operator or an external system.After processing the degradation of the average illuminance, the procedure moves 500 to 516.

[0056] At 516, the method 500 adjusts the throughput of the fiber curing system (e.g., a rate at which fiber is pulled through the fiber curing system) in response to the sensed average illuminance. In one example, a table or function of empirically determined adjustments to a base fiber throughput through the fiber curing system is stored in memory and indexed based on a difference between a desired average illuminance and the measured average illuminance. For example, if the illuminance is Y watts / m 2 is less than a desired average illuminance, the rate at which the fiber moves through the fiber curing system can be reduced by N meters / second. Similarly, if the illuminance is Y watts / m 2greater than the desired average illuminance, the rate at which the fiber moves through the fiber curing system can be increased to reduce energy waste.

[0057] Further, in one example, a current flow through a plurality of light arrays may be increased when the average illuminance in the first and second elliptical reflective chambers is less than a first threshold illuminance. Similarly, a current flow through the plurality of light arrays may be decreased when the average illuminance in the first and second elliptical reflective chambers is greater than a second threshold illuminance. Thus, the illuminance may be a closed-loop control controlled to improve the efficiency of the fiber curing system. After making adjustments to the fiber curing system, method 500 proceeds to 518.

[0058] At 518, method 500 decides whether or not to determine an illuminance at each optical fiber position. In one example, the luminance at which an optical fiber samples luminance in one of the two elliptical reflective chambers may indicate a luminance of a particular illumination array. The output of a specific illumination array may thus be determined from the output of a specific optical fiber sampling a position in one of the two elliptical reflective chambers.

[0059] The method 500 may determine that it is desirable to determine the illuminance at each optical fiber position in response to an average light intensity determined at 510 or other conditions such as curing system operating time. If the method 500 determines to determine the illuminance at each optical fiber position, the answer is yes, and the method 500 proceeds to 520. Otherwise, the answer is no, and the method 500 proceeds to the end.

[0060] At 520, method 500 determines the illuminance emitted by each optical fiber entering one of the two elliptical reflective chambers. In one example, the output from multiple photodetectors is converted into multiple illuminance values ​​with units of watts / m 2converted. Each of the plurality of illuminance values ​​corresponds to an illuminance at a position in one of the two elliptical reflection chambers. Method 500 proceeds to 522 after the illuminance at the plurality of positions is determined.

[0061] At 522, a decision is made as to whether or not the light intensity at one or more of the positions in the two elliptical reflective chambers is less than a first threshold or greater than a second threshold. In some examples, first and second thresholds are provided for each optical fiber that detects light in the two elliptical reflective chambers. The output from each optical fiber photodetector pair is compared to the first and second thresholds corresponding to the optical fiber. If the output from one or more optical fiber photodetector pairs is less than a first threshold or greater than a second threshold, the answer is yes, and method 500 proceeds to 524. Otherwise, the answer is no, and method 500 proceeds to the end.

[0062] At 524, the method 500 determines whether or not to adjust electrical power to one or more illumination arrays having an illumination intensity less than a first value or greater than a second value. In one example, the method 500 may adjust the electrical power to one or more illumination arrays in response to whether or not the fiber curing system has been activated for a threshold amount of time. If the method 500 determines to adjust the electrical power delivered to one or more illumination arrays, the answer is yes, and the method 500 proceeds to 526. Otherwise, the answer is no, and the method 500 proceeds to the end.

[0063] At 526, method 500 adjusts power supplied to illumination arrays that emit light at a luminous intensity below a first threshold or above a second threshold. In particular, electrical power supplied to an illumination array that directs a portion of its emitted light to an optical fiber that detects light in an elliptical reflective chamber may be adjusted when the optical fiber and its associated photodetector detect a luminous intensity below a first threshold or above a second threshold. Specifically, if it is determined that a particular illumination array is emitting less than a desired luminous intensity, current flow to the particular illumination array may be increased to increase the luminous intensity emitted by the particular illumination array. Electrical power supplied to surrounding light arrays is not adjusted.Similarly, if it is determined that a particular lighting array is emitting more than a desired light intensity, current flow to the particular lighting array may be reduced to reduce the light intensity emitted by the particular lighting array. Method 500 adjusts electrical power to lighting arrays that emit light intensity above or below a desired illumination range intensity bounded by the first and second light intensity thresholds and proceeds to 528.

[0064] At 528, method 500 adjusts a coolant flow for cooling lighting arrays. In one example, the coolant flow rate is adjusted in response to adjusting the amount of electrical energy added to or subtracted from a base amount of electrical energy supplied to the lighting arrays by illumination sources to compensate for a light intensity that is less than or greater than a desired light intensity. For example, if a current supplied to a light array reduces an electrical power supplied to the light array by 100 watts, the coolant flow to the light source may be reduced by 5%. Similarly, if a current supplied to a light array increases the electrical power supplied to the light array by 100 watts, the coolant flow to the light source may be increased by 5%. After adjusting the coolant flow, method 500 proceeds to 530.

[0065] At 530, method 500 determines whether one or more illumination arrays are not responding as desired to electrical power adjustments. Specifically, at 520, light is received from optical fibers as described, and the light intensity is compared to a target light intensity for each optical fiber after the electrical power adjustments are made at 526. If one or more illumination arrays are not responding to the electrical power adjustments, the answer is yes, and method 500 proceeds to 532. Otherwise, the answer is no, and method 500 proceeds to the end.

[0066] At 532, method 500 attempts to compensate for the output of lighting arrays that do not respond as desired to electrical power adjustments. Note that electrical power adjustments (e.g., adjusting current flow to a lighting array) are used to adjust the light intensity emitted by light arrays. In one example, the electrical power is adjusted to lighting arrays that are adjacent or near the lighting array that does not respond as desired to electrical power. By adjusting the electrical power delivered to adjacent lighting arrays, it may be possible to provide an equal average light intensity, as if all lighting arrays were operating as desired. Therefore, it may be possible to continue operating the fiber curing system even if one lighting array is not operating as desired.Alternatively, it may be possible to stop the application of fiber coating and cure a fiber coating that was already applied before stopping the fiber curing system in order to retain one or more illumination arrays that are not responding as desired.

[0067] For example, if an illumination source comprises illumination arrays arranged in three rows and one column (3, 1), and wherein the illumination array in the second row directs a portion of its light output toward the position of a second optical fiber in the first elliptical reflective chamber, and the second optical fiber and its associated photodetector output a light intensity outside a specified range, a current supplied to the illumination arrays in the first and second rows can be adjusted while maintaining the current supplied to the illumination array in the second row at its current value. Note that light output by the first and third illumination arrays lies within a threshold light intensity range determined by the optical fiber and photodetectors that receive a portion of the light output by the first and third illumination arrays.The electrical power supplied to the first and third light arrays can be adjusted by changing the resistance of variable resistors, as shown in . Fig. 2 is described.

[0068] At 534, method 500 outputs an indication of degradation of the fiber curing system, as described at 514. After outputting the degradation of the fiber curing system, method 500 proceeds to 536.

[0069] At 536, method 500 reduces the fiber curing system throughput. Because the fiber curing system may be part of a larger fiber manufacturing system, in response to degradation of the illumination system, the fiber curing system may send a message to an external controller to reduce the rate at which fiber flows through the fiber curing system. In one example, a message to reduce the throughput of fiber through the fiber curing system is based on a difference between a desired average light intensity in the elliptical reflective chambers of the fiber curing system and an actual average light intensity in the elliptical reflective chambers of the fiber curing system. For example, if the average light intensity of the elliptical reflective chamber of the fiber curing system is 5% lower than desired, the rate of fiber flowing through the fiber curing system may be reduced by X meters / second.In this way, a fiber flowing through the fiber curing system can be exposed to light long enough for the coating to cure, even if the illuminance in the elliptical reflective chambers is lower than desired. In some examples, the fiber throughput can be reduced to zero if the average illuminance in the elliptical reflective chambers of the fiber curing system is less than a threshold illuminance. After adjusting the fiber curing system throughput, method 500 proceeds to completion.

[0070] Thus, the procedure of Fig. 5 provides a method of operating a fiber curing system, comprising: receiving an amount of light energy emitted by two light sources providing light to a dual elliptical reflective chamber; and adjusting operation of a fiber curing system in response to the amount of light energy. The method includes adjusting operation of the fiber curing system comprising providing an indication of degradation to a controller or operator. The method further includes adjusting the output of one or more light arrays in one of the two light sources in response to an amount of light energy detected in an elliptical reflective chamber of the dual elliptical reflective chamber. The method also includes adjusting operation of the fiber curing system comprising providing an indication to reduce fiber curing system fiber throughput.The method includes adjusting the operation of a fiber curing system comprising providing an indication to adjust the coolant flow to at least one of the two light sources. The method includes adjusting the operation of a fiber curing system comprising adjusting electrical energy supplied to at least one of the two light sources.

[0071] With reference now to Fig. 6 shows a method for determining the transparency and / or light transmission for a fiber curing system. The method of Fig. 56 can be stored in a non-volatile memory as executable instructions for a control unit, such as the one in Fig. 2 shown control unit 208. The method of Fig. 6 may be part of the Fig. 1-4 shown system.

[0072] At 602, method 600 determines whether or not to activate a fiber curing system. The fiber curing system may be activated in response to an operator or controller input. If method 600 determines to activate the fiber curing system, method 600 proceeds to 604. Otherwise, method 600 ends.

[0073] At 604, the method 600 activates two light sources (e.g., 112 and 113 of Fig. 1) on two opposite sides of the two elliptical reflecting chambers. In one example, the light sources consist of one or more illumination device arrays. The arrays can be supplied with electrical power according to an illumination profile based on a position of each illumination array in the respective light sources. In one example, the illumination profile provides an equal amount of electrical power to each array in the respective light sources. In other examples, each array can be supplied with a unique amount of electrical power based on a position of the array in the light source according to the illumination profile, as in Fig. 5. The method 600 proceeds to 606 after activating the two light sources.

[0074] At 606, method 600 activates the fiber curing tube's transparency and / or translucency light source and the light beam receivers. In one example, the fiber curing tube's transparency and / or translucency monitoring and control system activates two light sources and two light beam receivers (e.g., photodetectors). The two light sources and two light beam receivers may be located at opposite ends of a curing tube. Method 600 proceeds to 608 after the two light sources and two light beam receivers are activated.

[0075] At 608, method 600 compares the outputs of the light beam receivers to light beam threshold values. In one example, the light beam receiver outputs are compared to a table or function of empirically determined curing tube transparency and / or light transmission values ​​stored in memory. The table or function outputs a transparency and / or light transmission value from 0 to 1 for each light beam receiver based on an output from each light beam receiver. A light transmission value of zero corresponds to no light energy passing through the curing tube from the curing tube transparency light source positioned opposite the curing tube transparency photodetector.A light transmittance value of one corresponds to more than a predetermined threshold amount of light energy passing through the curing tube from the curing tube's translucent light source positioned opposite the curing tube's translucent photodetector. It should also be noted that the curing tube's translucent light source may have a different wavelength than the fiber curing light source, so that the curing tube's translucent photodetector is not affected by light from the fiber curing light source. In other examples, the curing tube's translucent light source may be of the same wavelength as the fiber curing light source.

[0076] In some examples, the estimated curing tube light transmittance for the plurality of curing tube positions may be stored in memory so that a curing tube light transmittance degradation rate may be determined. For example, an estimate of the curing tube light transmittance at a prior time may be subtracted from a curing tube light transmittance at the current time, and the result may be divided by the time difference between the prior time and the current time to provide a light transmittance degradation rate. After determining the curing tube transparency and / or light transmittance at a plurality of curing tube positions, method 600 proceeds to 610.

[0077] At 610, method 600 determines whether or not the transparency or light transmittance of the curing tube at the plurality of curing tube positions is less than a first threshold light transmittance. The first threshold light transmittance may vary with the type of coating applied to the fiber and / or other curing system conditions. If method 600 determines that the transparency or light transmittance of the curing tube is less than a first threshold light transmittance value, the answer is yes, and method 600 proceeds to 630. Otherwise, the answer is no, and method 600 proceeds to 612.

[0078] At 612, method 600 adjusts the light output intensity of a plurality of light arrays in response to the transparency or translucency of the curing tube. By adjusting the current supplied to the light arrays, the light intensity may be able to compensate for a degradation in the transparency and / or translucency of the curing tube. For example, if the translucency of the curing tube is reduced by 5%, the light intensity may be increased to compensate for the reduced translucency of the curing tubes.In one example, a table or function of empirically determined adjustments to the illumination array current may be provided such that the illumination array current changes the emitted light intensity of the illumination array to provide an equivalent amount of light energy after the curing tube begins to be covered with material, compared to before the curing tube begins to be covered with material. In this way, a substantially equivalent amount of light energy (e.g., the baseline light energy + 5%) may be delivered to the fiber for at least a period of time after material begins to accumulate in the curing tube.

[0079] Furthermore, if electrical current is delivered to multiple lighting arrays according to a profile that specifies a potentially unique amount of current for each light array in the fiber curing system, the current amounts in the profile can be adjusted by a curing tube transparency or translucency modifier, so that the current delivered to the lighting arrays is provided according to a scaled version of the lighting current profile. Note that light arrays on both sides of the curing tube are adjusted in response to curing tube translucency.

[0080] Further, the method 600 may compare the desired light intensity, including adjustments for curing tube light transmission, with detected light, as in Fig. 5. Thus, the light intensity, which includes adjustments for curing tube light transmission, can be adjusted in a closed-loop manner so that a desired amount of light energy reaches the fiber. After adjusting the current supplied to the light arrays, method 600 proceeds to 614.

[0081] At 614, method 600 communicates with an external controller or adjusts a pump and / or valve to change a flow of inert gas through the curing tube in response to the degradation rate of the light transmittance of the curing tube. In one example, a gas flow adjustment of the inert gas flowing through the curing tube is based on the light transmittance of the curing tube. The external controller may adjust the power of a pump and / or a flow control valve to adjust the inert gas flow rate. By adjusting the inert gas flow rate, it may be possible to reduce the degradation rate of the light transmittance of the curing tube.If the curing tube light transmittance deteriorates at an expected rate, the inert gas flow rate is maintained at its current rate, or the inert gas flow rate may be reduced if the curing tube light transmittance deteriorates at a rate slower than expected. After adjusting the inert gas flow rate, method 600 proceeds to 616.

[0082] At 616, method 600 communicates with an external controller or adjusts a pump and / or valve to change a coolant flow through a lighting array heat sink in response to lighting array current adjustments provided at 612. In one example, an adjustment of the coolant flow rate to the heat sink is based on a change in the electrical current or power supplied to the lighting arrays. The external controller may adjust the power of a pump and / or a flow control valve to adjust the coolant flow rate. By adjusting the coolant flow rate, it may be possible to maintain the LEDs of the lighting arrays at a target temperature. After adjusting the coolant flow rate, method 600 proceeds to 618.

[0083] At 618, method 600 may store curing tube light transmission values, illumination array currents, the rate and / or extent of curing tube light transmission degradation, and other control variables in memory. Further, method 600 may report operating conditions and indications of curing tube degradation to an operator or an external controller so that the fiber curing system and other fiber manufacturing systems can take desired actions, such as adjusting fiber throughput and adjusting the amount of coating applied to the fiber. After reporting the fiber curing system conditions and / or storing them in memory, method 600 proceeds to exit.

[0084] At 630, method 600 adjusts the light output intensity of a plurality of light arrays in response to the transparency or translucency of the curing tube, as described at 612. After adjusting the light output intensity, method 600 proceeds to 632.

[0085] At 632, method 600 communicates with an external controller or adjusts a pump and / or valve to change a flow of inert gas through the curing tube in response to the degradation rate of the light transmittance of the curing tube, as described at 614. After adjusting the inert gas flow, method 600 proceeds to 634.

[0086] At 634, method 600 communicates with an external controller or adjusts a pump and / or valve to vary coolant flow through a lighting array heat sink in response to adjustments to the lighting array electrical current provided at 630, as described at 616. After adjusting the coolant flow rate, method 600 proceeds to 636.

[0087] At 636, method 600 communicates with an external controller or adjusts the fiber throughput or fiber flow rate through the fiber curing system in response to an estimate of the light energy reaching the fiber through the curing tube. In one example, an estimate of light energy at the fiber is based on an amount of light energy emitted by the illumination arrays and the estimated light transmittance of the curing tube. In one example, the light transmittance may be assigned as a number from 0 to 1, as described at 608, and the assigned value is multiplied by an illumination efficiency factor and the light energy emitted by the light arrays to determine an amount of light energy at the fiber. The fiber throughput is adjusted based on the estimated light energy at the fiber.The fiber throughput adjustment can be determined empirically and stored in a table or function indexed by the estimate of the light energy at the fiber. After adjusting the fiber throughput, the method 600 proceeds to 638.

[0088] At 638, method 600 may store curing tube light transmission values, illumination array electrical currents, the rate and / or extent of curing tube light transmission degradation, and another control variable in memory, as described at 618. After recording and / or reporting fiber curing system degradation, method 600 proceeds to 640.

[0089] At 640, method 600 determines whether the curing tube light transmittance is less than a second predetermined threshold light transmittance. If yes, the answer is yes and method 600 proceeds to 642. Otherwise, the answer is no and method 600 proceeds to end.

[0090] At 642, method 600 indicates that a high cure tube degradation value is present. The indication of cure tube degradation may be provided to an external controller so that actions such as adjusting fiber throughput may be provided. In some examples, the fiber throughput may be reduced to zero when the second cure tube degradation value is determined. After indicating the second cure tube degradation value, method 600 proceeds to the end.

[0091] It should be mentioned that the procedures of Fig. 5 and Fig. 6 can be performed and executed together, so that the fiber curing system benefits from both processes. Furthermore, the two processes can exchange information, such as light intensity information for the elliptical reflecting chambers.

[0092] As will be apparent to a person of ordinary skill in the art, the Fig. 5 and Fig.6 may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. Thus, various steps or functions shown may be performed in the order shown, in parallel, or in some cases skipped. Similarly, the order of processing is not required to achieve the objects, features, and advantages described herein, but is provided for ease of illustration and description. Although not specifically shown, one of ordinary skill in the art will recognize that one or more of the steps or functions shown may be performed repeatedly depending on the particular strategy employed.

[0093] This concludes the description. A reading of the description by those skilled in the art may suggest many modifications and variations without departing from the spirit and scope of the description. For example, illumination sources that produce different wavelengths of light may benefit from the present description.

Claims

[1] A system (100) for monitoring fiber curing, comprising: an elliptical reflective chamber (302, 303) comprising at least two light detecting apertures (320, 321); at least two light sources (112, 113), each of the at least two light sources (112, 113) being directed toward a curing tube (126), the curing tube (126) being positioned between the at least two light sources (112, 113) and in at least a portion of the elliptical reflective chamber (302, 303); and a light receiver (155, 156) which is in optical connection with the at least two light detection openings (320, 321). [2] The system (100) of claim 1, further comprising a controller (208) having executable instructions stored in a non-volatile memory (292) for indicating degradation of the at least two light sources (112, 113). [3] The system (100) of claim 1, wherein the light receiver (155, 156) is coupled to the at least two light sensing apertures (320, 321) by means of at least two optical fibers (114, 115). [4] The system (100) of claim 1, wherein a first (320) of the at least two light sensing apertures (320, 321) is positioned between a first (112) of the at least two light sources (112, 113) and the curing tube (126), and wherein a second (321) of the at least two light sensing apertures (320, 321) is positioned between a second (113) of the at least two light sources (112, 113) and the curing tube (126). [5] The system (100) of claim 1, wherein a first (112) of the at least two light sources (112, 113) consists of a plurality of LED arrays arranged in a first column, and wherein a second (113) of the at least two light sources (112, 113) consists of a plurality of LED arrays arranged in a second column. [6] The system (100) of claim 5, wherein the elliptical reflective chamber (302, 303) further comprises light sensing apertures (320, 321) for each LED array in the first and second columns. [7] The system (100) of claim 5, wherein the first column and the second column are arranged along a long axis (170) of the curing tube (126). [8] The system (100) of claim 1, further comprising a controller (208) having executable instructions stored in a non-volatile memory (292) for indicating a desire to reduce, but not stop, fiber throughput for a fiber UV curing system.

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