KR20210093633A - Design and Fabrication Techniques of an Underwater High-luminance Rescue-rope by the Side-emission Control of Optic Fiber - Google Patents

Abstract

Presented is the design and manufacturing technology of an underwater visible lifeline by optical fiber surface luminance control technology. An underwater visible lifeline system proposed in the present invention includes: a light source unit including a device on board (DOB) and a heat sink for high-density light integration; a light condensing system applying a multi-layer glass lens so that all the light flux transmitted from the light source unit is focused on the core of the optical fiber; a jacket layer consisting of three layers of a core, a cladding, and a jacket and controlling the side reflection of the light flux; and a lifeline designed as a reflective cap to increase the surface luminance by reflecting the light flux at the distal end of the optical fiber.

Description

Design and Fabrication Techniques of an Underwater High-luminance Rescue-rope by the Side-emission Control of Optic Fiber

The present invention relates to a method and apparatus for designing and manufacturing an underwater visualization lifeline by high-brightness emission control technology of optical fiber.

The underwater lifeline has been used for the smooth activities of divers, such as lifesaving, search, investigation and filming, and to secure a return route in the water. A previous study was conducted to visualize the lifeline by applying a side-emitting optical fiber and LED instead of a non-luminous rope made of Nylon, PE or PP material, and experimentally confirmed that it can be used sufficiently in the water. However, in previous studies, the optical fiber was damaged due to heat from the light source, making it impossible to use for a long time. Therefore, it was necessary to study the low-current driving of the LED and the high efficiency of the light.

The radiated light of the prototype underwater visualization lifeline is a green wavelength of 525 nm with excellent light transmittance, and the surface brightness is 120 cd/m ² , which solves the fundamental problem of the existing non-luminous lifeline. In a previous study of the visual lifeline, the maximum luminance of the optical fiber end surface at 10 A was 1,500 [cd/m ² ], but damage to the optical fiber due to the heat of the LED occurred frequently.

The technical problem to be achieved by the present invention is to provide a design and manufacturing technology for an underwater visualization lifeline by optical fiber surface brightness control technology that can be used stably with high brightness for a long time by maximizing electro-optical characteristics.

In one aspect, the underwater visualization lifeline system proposed in the present invention applies a light source unit including a DOB (Device on Board) and a heat sink, and a multi-layer glass lens for high integration of light, the luminous flux transmitted from the light source unit It consists of a condensing system to be focused on the core of the optical fiber, a core-clad-jacket, and the outermost jacket layer includes a lifeline designed for reflection.

The lifeline includes a jacket for preventing a decrease in surface luminance due to an increase in a luminous flux emitted to the outside as the optical fiber moves away from the incident point of the light transmitted from the light source in the longitudinal direction.

On the outside of the jacket, a 100cm-long auxiliary jacket with a transmittance of 20% and a reflectance of 50% is installed at regular intervals.

The lifeline includes a reflective cap to increase the brightness of the surface by reflecting the beam of light at the end of the optical fiber.

The beam angle of the multi-layer glass lens of the condensing system is within 60°, and it is inserted between the light source unit and the optical fiber.

The light source unit adjusts the current to vary the amount of light or luminance.

In another aspect, the method for controlling the surface luminance of the underwater visualization lifeline proposed in the present invention comprises the steps of controlling the amount of light or luminance by controlling the current through the light source unit, and a multi-layer glass lens in the condensing system. Applying so that all the luminous flux transmitted from the light source unit is concentrated on the core of the optical fiber, as the optical fiber moves away from the incident point of the light transmitted from the light source unit through the jacket in the longitudinal direction, the luminous flux emitted to the outside increases and the surface luminance decreases and increasing the luminance of the surface by reflecting the light beam through a reflective cap at the end of the optical fiber.

In the step of controlling the amount of light or luminance by controlling the current through the light source, commercial alternating current (AC) and capacitor (DC) are used together in consideration of portability and long-term use.

The step of controlling the amount of light or luminance by controlling the current through the light source unit controls to display the amount of residual energy of the storage battery when the power is cut off during the underwater rescue or search operation.

According to the embodiments of the present invention, it is possible to provide a design and manufacturing technology for an underwater visualization lifeline by an optical fiber surface brightness control technology that can be used stably for a long time with high brightness by maximizing the electro-optical characteristics. As the core technology proposed, the optimal condensing system for LED light source and optical fiber, shielding and reflection control of the optical fiber jacket, and applying a reflector to the end of the optical fiber resulted in an increase in surface brightness by more than 180% at the same power consumption.

1 is a view showing the structure of an optical fiber according to an embodiment of the present invention.
Figure 2 is a view showing the configuration of the underwater visualization lifeline system according to an embodiment of the present invention.
3 is a view showing the structure of a light collecting system according to an embodiment of the present invention.
Figure 4 is a view showing the structure of the jacket according to an embodiment of the present invention.
5 is a view showing the structure of a reflective cap according to an embodiment of the present invention.
6 is a flowchart for explaining a method for controlling the surface brightness of an underwater visualization lifeline according to an embodiment of the present invention.
7 is a graph showing a change in surface luminance at the end of an optical fiber when all three luminance increasing methods according to an embodiment of the present invention are applied.
8 is a current-luminance graph according to an embodiment of the present invention.

The material of the optical fiber applied to the visualization of the underwater lifeline is PMMA (Poly-methyl methacrylate), and there is no problem with corrosion or electrical insulation in the water, and the light attenuation rate at the core is 0.16 db/m. The quantitative evaluation index of the lifeline is the brightness at which a diver can recognize the lifeline from a certain distance, so the surface luminance cd/m ² of the optical fiber is the standard. The specification of the light source used in the experiment was a DOB (Device on Board) type 525nm green LED shown in Table 1, and the same as that of the previous study was used. A key factor in selecting a light source for an underwater lifeline is that the luminous area should be within the core area of the optical fiber, and the luminous flux per unit area (lm/mm ² ) should be high. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Table 1>

1 is a view showing the structure of an optical fiber according to an embodiment of the present invention.

Fig. 1(a) shows an optical fiber for optical communication, and Fig. 1(b) shows an optical fiber for side emission.

The structure of optical communication and side-emitting optical fiber is generally composed of a core, a clad, and a jacket as shown in FIG. 1 . The core is a light transmission path, and the cladding for optical communication blocks the light propagating inside the core, while the cladding for side emission is to emit a certain amount of light to the outside perpendicular to the light propagation path. In addition, the jacket for optical communication only serves to protect the clad, but for side light emission, a material with high transmittance is used to sufficiently radiate the light emitted from the clad to the outside while protecting the clad.

The specifications of the optical fiber used as the underwater lifeline in the present invention are shown in Table 2.

<Table 2>

In order to increase the surface luminance of the side-emitting optical fiber, an experimental study was conducted on the following contents.

- LED light source and optical fiber condensing system

- Shielding and reflection control of fiber optic jacket

- Application of reflector

Figure 2 is a view showing the configuration of the underwater visualization lifeline system according to an embodiment of the present invention.

The proposed underwater visualization lifeline system includes a light source unit 230 , a light collecting system 210 , and a lifeline 220 .

The light source unit 230 includes a power supply unit and a charging unit 231 , a control unit 232 , and an LED 233 . The light source 230 includes a device on board (DOB) and a heat sink for high integration of light.

The light condensing system 210 applies a multi-layer glass lens so that all of the light flux transmitted from the light source unit is concentrated on the core of the optical fiber. The beam angle of the multi-layer glass lens of the condensing system 210 is within 60°, and is inserted between the light source unit and the optical fiber.

3 is a view showing the structure of a light collecting system according to an embodiment of the present invention.

The beam angle of the LED is 110˚ or more unless a separate lens is applied, and the high-power LED has a temperature of 100°C or more due to radiant heat from the light emitting surface, so that the light emitting surface of the LED and the core of the optical fiber are in direct contact. Doing so will cause damage to the optical fiber. As shown in Fig. 3(a), it is necessary to space the LED and the optical fiber at least 10 mm apart to prevent damage to the optical fiber from radiant heat. In this case, only about 60% of the radiant flux from the LED is condensed on the core and the rest is lost. Therefore, in order to maximize the use of the radiated flux, it is necessary to focus light between the LED and the optical fiber.

Therefore, in the present invention, an optimal light condensing structure in which the light flux from the LED is concentrated on the core of the optical fiber is applied by applying the multi-layer glass lens secured in the LED searchlight research and development process.

The beam angle of the condensing system of the 4-layer glass lens is within 60°, and the height is 10 mm and is inserted between the LED and the optical fiber as shown in FIG. 3(b). The light collection efficiency of Fig. 3(a) without the light condenser and Fig. 3(b) with the light condenser is compared from the ratio of the emission area at a distance of 10 mm from the LED as follows.

In FIG. 3(a) , the radius through which the light beam passes for a beam angle of 120° is 17.32 mm, and the solid angle cross-sectional area at this time is about 940 mm ² . Among them, only the light beam incident on a cross-sectional area of 200 mm ^{2 corresponding to a radius of 8 mm passes through the core.} In FIG. 3(b), since the radius through which the light beam passes at the beam angle of 60° becomes 5.75 mm, all the light beams corresponding to the beam angle of 120° are focused on the core.

As such, by applying the light condensing system with a beam angle of 60°, the luminous flux focused on the core increases by about 470%, and even considering the transmission and reflection loss of 30% in the optical system, it increases by 330% compared to the case without the optical system.

According to the embodiment of the present invention, the surface luminance of the end of the optical fiber was increased by about 170% by applying the condenser in the experiment of the 20 m-long optical fiber with the forward current of the LED constant at 5A.

The lifeline 220 is composed of three layers of the core 221 - the clad (that is, the shield) 223 - the jacket 222, and the outermost jacket layer is designed to be reflective. The lifeline 220 includes a jacket 222 for preventing a decrease in surface brightness due to an increase in the luminous flux emitted to the outside as the optical fiber moves away from the incident point of the light transmitted from the light source in the longitudinal direction.

4 is a view showing the structure of the jacket according to an embodiment of the present invention.

The light emitted from the surface of the optical fiber is diffused into the water, and the higher the surface brightness, the more divers can perceive from a distance at the same turbidity.

Therefore, in the present invention, as the optical fiber is farther away from the incident point of light on the optical fiber in the longitudinal direction, the surface luminance decreases due to the large amount of luminous flux emitted to the outside. Auxiliary jackets were installed at intervals of 10 cm.

5 is a view showing the structure of the jacket according to an embodiment of the present invention.

The lifeline 220 includes a reflective cap for increasing the luminance of the surface by reflecting the light beam at the end of the optical fiber.

The luminance of the cross section of the optical fiber is several tens of times greater than the surface luminance, and the light flux passing through the cross section is radiated into the water.

6 is a flowchart for explaining a method for controlling the surface brightness of an underwater visualization lifeline according to an embodiment of the present invention.

The method of controlling the surface luminance of the underwater visualization lifeline includes the step of controlling the amount of light or the luminance by controlling the current through the light source unit (610), and applying a multi-layer glass lens to the condensing system so that all of the luminous flux transmitted from the light source unit is Step of concentrating on the core of the optical fiber (620), as the optical fiber moves away from the incident point of the light transmitted from the light source through the jacket in the longitudinal direction, the luminous flux emitted to the outside increases to prevent the decrease in surface luminance (630) ) and reflecting the light beam through the reflective cap at the end of the optical fiber to increase the luminance of the surface (640).

In step 610, the light quantity or luminance is controlled by adjusting the current through the light source unit.

In the visualization lifeline system to which all of the proposed optical fiber surface luminance increase methods are applied, the power supply unit can be used in combination with commercial alternating current (AC) and capacitor (DC) in consideration of portability and long-term use. If the lifeline is cut off during underwater rescue or search operation, there is a risk to the activities of divers and securing the return route, so the amount of energy remaining in the battery is displayed.

In step 620, a multi-layer glass lens is applied to the condensing system so that all of the luminous flux transmitted from the light source is focused on the core of the optical fiber.

In step 610, as the optical fiber moves away from the incident point of the light transmitted from the light source through the jacket in the longitudinal direction, the luminous flux emitted to the outside increases, thereby preventing a decrease in surface luminance.

In step 640, the luminance of the surface is increased by reflecting the light beam through the reflective cap at the end of the optical fiber.

For the LED, the same DOB type as in the previous study was used, and a constant current type step-down converter was used to drive the LED. The prototype is operated at 5A, 4.7V, and the fiber optic jacket and reflector are applied to design a high-brightness lifeline system that can be used in environments with high turbidity.

7 is a graph showing the change in surface luminance at the end of an optical fiber when all three luminance increasing methods according to an embodiment of the present invention are applied.

As the number of jackets increases, it can be seen that the surface luminance greatly increases when the reflective cap is installed at each stage. This is because, as described above, the luminous flux lost to the outside of the optical fiber core is reduced and the internal luminous flux is increased with the reflective cap. It was evaluated as a maximum of 280% with the auxiliary jacket and a maximum of 430% of the cumulative brightness increase due to the application of the reflective cap.

Divers are expecting a high-brightness lifeline that can be used even in an environment with high turbidity due to floating matter or microorganisms at the level, so in the present invention, a condensing system that concentrates the light beam from the LED on the core of the existing side-emitting optical fiber, a jacket ) shielding and reflectance control, and by applying a reflector to the end of the optical fiber, a study was conducted to stably improve the surface brightness of the LED under the same conditions as in previous studies. As such, lifelines using side-emitting optical fibers do not require separate electrical wiring, so electrical insulation and waterproofing are fundamentally solved in the water, and by securing high brightness, systems such as ship construction, railroad platform safety lines, induction lines and landscapes of tunnels It is expected that it can be used in a variety of ways with technological and economic differentiation.

8 is a current-luminance graph according to an embodiment of the present invention.

As a prototype, the luminance of the end surface of the optical fiber was compared with the results of previous studies. In the previous study, the driving current of the LED was increased to increase the luminance, and as shown in FIG. 8 , the maximum was 1,650 cd/m ^{2 at 10A and 970 cd/m 2} at the driving current of 5A. By applying the LED and optical fiber condensing system, the shielding and reflection control of the optical fiber jacket, and the reflective cap proposed in the present invention, it was possible to obtain a luminance increase of about 180% ^{at 1,750 cd/m 2 at the same driving current of 5A.}

The present invention proposes a high-brightness scheme for an underwater lifeline. In the optimal light condensing system of LED light source and optical fiber, only about 60% of the radiation beam from the LED light source is condensed on the core, and the rest is incident on the outside of the cladding and is lost. The radius through which the light beam passes for a beam angle of 120° is 17.32 mm, and the solid angle cross-sectional area at this time is about 940 mm ² . Among them, only the light beam incident on a cross-sectional area of 200 mm ^{2 corresponding to a radius of 8 mm passes through the core.} Since the radius through which the light beam passes at a beam angle of 60° becomes 5.75 mm, all of the light beams corresponding to the beam angle of 120° are focused on the core. As such, by applying the light condensing system with a beam angle of 60°, the luminous flux focused on the core increases by about 470%, and even considering the transmission and reflection loss of 30% in the optical system, it increases by 330% compared to the case without the optical system. In the shielding and reflection control of the optical fiber jacket, the farther the optical fiber is from the light incident point of the optical fiber in the longitudinal direction, the more the luminous flux radiates to the outside, and the surface luminance decreases. Therefore, a 100 cm-long auxiliary jacket having a transmittance of 20% and a reflectance of 50% is attached to the outside of the optical fiber jacket at an interval of 10 cm. In this way, a dotted line can be produced and the light attenuation rate is reduced. In the application of the reflector, the luminance at the cross section of the optical fiber is several tens of times higher than the maximum luminance on the surface of the optical fiber, and the luminous flux passing through the cross section is radiated into the water. Therefore, a maximum of 280% with the auxiliary jacket and a maximum of 430% of the cumulative luminance increase due to the application of the reflective cap were evaluated.

In the previous study, the maximum luminance was 1,650 cd/m ² at 10 A, but it was possible to obtain a luminance increase of about 180% from 5 A to 1,750 cd/m ^{2 through the high luminance method.} These three high luminance methods achieved a drastic increase in the existing luminance. This increase in brightness is expected to help the various rescue activities of existing divers, and is also expected to enable utilization in various fields.

In the present invention, an LED light system to which an optical fiber is applied is proposed to visualize the lifeline required for efficient underwater activities and return of divers. According to an embodiment of the present invention, light is transmitted at a green wavelength (525 nm) of optimal visibility using an LED module having a power consumption of 40 W. By applying optical fiber as a lifeline, sufficient tensile strength could be obtained, and it has strong durability against bending and damage from external impacts, and no additional waterproof structure is required, so it is optimal as an underwater lifeline function.

The luminance of the surface of the lifeline at 5 A in the proposed visualization lifeline system is 1,750 cd/cm ² , which is 14.5 times higher than that of the surface luminance of 120 cd/cm ^{2 in the experimental underwater lifeline system.} do. The manufactured visualization lifeline system is expected to be widely used as it can produce various colors and control brightness by changing the light source according to the purpose.

The device described above may be implemented as a hardware component, a software component, and/or a combination of the hardware component and the software component. For example, devices and components described in the embodiments may include, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA), It may be implemented using one or more general purpose or special purpose computers, such as a programmable logic unit (PLU), microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For convenience of understanding, although one processing device is sometimes described as being used, one of ordinary skill in the art will recognize that the processing device includes a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that can include For example, the processing device may include a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as parallel processors.

Software may comprise a computer program, code, instructions, or a combination of one or more of these, which configures a processing device to operate as desired or is independently or collectively processed You can command the device. The software and/or data may be any kind of machine, component, physical device, virtual equipment, computer storage medium or device, to be interpreted by or to provide instructions or data to the processing device. may be embodied in The software may be distributed over networked computer systems, and stored or executed in a distributed manner. Software and data may be stored in one or more computer-readable recording media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, etc. alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiment, or may be known and available to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic such as floppy disks. - includes magneto-optical media, and hardware devices specially configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like.

As described above, although the embodiments have been described with reference to the limited embodiments and drawings, various modifications and variations are possible for those skilled in the art from the above description. For example, the described techniques are performed in a different order than the described method, and/or the described components of the system, structure, apparatus, circuit, etc. are combined or combined in a different form than the described method, or other components Or substituted or substituted by equivalents may achieve an appropriate result.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (9)

a light source unit including a device on board (DOB) and a heat sink for high integration of light;
a condensing system that applies a multi-layer glass lens so that all of the light flux transmitted from the light source is focused on the core of the optical fiber; and
The lifeline consists of three layers of core-clad-jacket and the outermost jacket layer is reflective design.
Including an underwater visualization lifeline system. According to claim 1,
lifeline,
A jacket for preventing a decrease in surface luminance due to an increase in the luminous flux emitted to the outside as the optical fiber moves away from the incident point of the light transmitted from the light source in the longitudinal direction
An underwater visualization lifeline system comprising a. 3. The method of claim 2,
A 100cm-long auxiliary jacket with 20% transmittance and 50% reflectance is installed on the outside of the jacket at regular intervals.
Underwater visualization lifeline system. According to claim 1,
lifeline,
Reflective cap to increase the luminance of the surface by reflecting the light flux at the end of the optical fiber
Including an underwater visualization lifeline system. According to claim 1,
The beam angle of the multi-layer glass lens of the condensing system is within 60°, and the
Underwater visualization lifeline system. According to claim 1,
light source,
By controlling the current, the amount of light or brightness
Underwater visualization lifeline system. controlling the amount of light or luminance by controlling the current through the light source;
applying a multi-layer glass lens to the condensing system so that all of the luminous flux transmitted from the light source unit is concentrated on the core of the optical fiber;
preventing a decrease in surface luminance due to an increase in the luminous flux emitted to the outside as the optical fiber moves away from the incident point of the light transmitted from the light source through the jacket in the longitudinal direction; and
Reflecting the light beam through a reflective cap at the end of the optical fiber to increase the luminance of the surface
A method of controlling the surface brightness of an underwater visualization lifeline comprising a. 8. The method of claim 7,
The step of controlling the amount of light or luminance by controlling the current through the light source unit,
Considering portability and long-term use, commercial alternating current (AC) and capacitors (DC) are used in combination.
A method of controlling the surface brightness of an underwater visualization lifeline. 8. The method of claim 7,
The step of controlling the amount of light or luminance by controlling the current through the light source unit,
When the lifeline is cut off during underwater rescue or search operation, it is a control system that displays the amount of energy remaining in the battery.
A method of controlling the surface brightness of an underwater visualization lifeline.

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