Lighting device with fiber optic module and method for manufacturing a fiber optic module

Abstract

Lighting device (1), comprising: a light source element (51) that emits laser light; a fiber optic module (2) into which the laser light is introduced; and a wavelength converter (60) that converts the laser light passed through the optical fiber module (2) into light with a different wavelength, the optical fiber module (2) comprises: an optical fiber (11) containing a glass component; and a sleeve (20) which is tubular and covers an outer circumferential surface (11a) in an end section (11c) of the optical fiber (11), wherein the outer circumferential surface (11a) of the optical fiber (11) and an inner circumferential surface (20a) of the sleeve (20) are connected by a silicone resin (30) which contains siloxane bonds at crosslinking points, and wherein the optical fiber (11) and the silicone resin (30) are irradiated with laser light when the laser light is introduced into the optical fiber module (2).

Description

[Technical field]

[0001] The present disclosure relates to a lighting device comprising an optical fiber module and a method for manufacturing an optical fiber module. [State of the art]

[0002] Conventionally known optical fiber modules comprise an optical fiber that guides laser light emitted by a light source. As an example of such an optical fiber module, PTL 1 discloses an optical fiber module comprising an optical fiber and a tubular sleeve into which an end section of the optical fiber is inserted. PTL 1 discloses fixing the optical fiber within the sleeve using an epoxy adhesive.

[0003] PTL 2 discloses a method for surface treatment of the fiber when the optical fiber is connected to a connector by means of a resin mold, and it describes the applicability to a fiber-to-fiber connection part when the optical fiber is used as an optical conventional transmission medium.

[0004] PTL 3 discloses a light guide in the form of an optical fiber bundle for transmitting illumination light from a light source device to an object to be observed, which allegedly has improved durability.

[0005] PTL 4 discloses a method for driving a light source device from which no light harmful to the human body is emitted. [Document List][Patent Document] [PTL 1] JP 2013- 125 195 A [PTL 2] JP S57- 125 915 A [PTL 3] JP 2 705 830 B2 [PTL 4] US 2014 / 0 015 413 A1 [Summary of the invention][Technical problem]

[0006] In the fiber optic module, laser light is introduced into an optical fiber by irradiating an end surface of the fiber with laser light emitted by a light source. During this irradiation, the epoxy adhesive bonding the fiber and the ferrule may also be irradiated in some cases. The problem is that the epoxy adhesive emits light when irradiated with laser light. Furthermore, this light emission reduces the accuracy of detecting the presence or absence of a break in the optical fiber within the illumination device that houses the fiber optic module.

[0007] Accordingly, it is an object of the present disclosure to provide an optical fiber module or the like which can suppress light emission from an adhesive by which an optical fiber and a sleeve are connected. [Solution to the problem]

[0008] The problem is solved by the lighting device comprising an optical fiber module and a method for manufacturing an optical fiber module according to the claims. [Advantageous effects of the invention]

[0009] The optical fiber module of the lighting device according to the present invention can suppress light emission from an adhesive by which an optical fiber and a sleeve are connected. [Brief description of the drawings] Fig. Figure 1 is a schematic view showing a lighting device according to a comparative example. Fig. Figure 2 is a perspective view showing an optical fiber module according to a comparative example. Fig. Figure 3A is a diagram showing a spectrum of optical feedback detected by an optical feedback sensor in a lighting device. Fig. 3B is a diagram showing a spectrum of light emitted by an epoxy resin alone. Fig. Figure 4 is a diagram showing the results of an accelerated high-temperature aging test performed on optical fiber modules. Fig. Figure 5 is a diagram showing a silicone resin used as an adhesive for the optical fiber module. Fig. Figure 6 is a diagram showing the presence / absence of damage to the end surface of the optical fiber module. Fig. Figure 7 is a schematic view showing a lighting device according to one embodiment. Fig. Figure 8 is a perspective view showing an optical fiber module of the lighting device according to one embodiment. Fig. Figure 9 is a front view and a cross-sectional view of an optical fiber module of the lighting device according to one embodiment. Fig. Figure 10 is a flowchart showing a method for manufacturing an optical fiber module according to one embodiment. [Description of embodiments]

[0010] (Underlying knowledge which forms the basis of the present disclosure)

[0011] First, the underlying knowledge that forms the basis of the present disclosure will be discussed with reference to the Fig. 1 to 6.

[0012] The Fig. Figure 1 is a schematic view showing the lighting device 101 according to the comparative example.

[0013] The lighting device 101 according to the comparative example comprises the light source device 150, the optical fiber module 102, which includes the optical fiber cable 110 and the sleeve 120, and the wavelength converter 160. The optical fiber cable 110 is formed with an optical fiber 111 and a coating material 112 that covers the optical fiber 111.

[0014] The light source device 150 comprises the light source element 151, the dichroic mirror 153, the converging lens 154 and the optical feedback sensor 156.

[0015] The laser light emitted by the light source element 151 is directed through the dichroic mirror 153 and the converging lens 154 into the optical fiber module 102. The laser light entering the optical fiber module 102 is then emitted by the optical fiber 111 and directed into the wavelength converter 160. The wavelength converter 160 converts the emitted laser light into light with a different wavelength and emits the light.

[0016] The optical feedback sensor 156 is a sensor for detecting the presence or absence of an interruption in the optical fiber 111. In the light emitted by the wavelength converter 160, the optical feedback sensor 156 detects optical feedback that returns via the optical fiber module 102, the converging lens 154, and the dichroic mirror 153. If this optical feedback is detected with an intensity within a predetermined range, the illumination device 101 determines that the optical fiber 111 is uninterrupted.

[0017] The Fig. Figure 2 is a perspective view showing the optical fiber module 102 according to the comparison example.

[0018] The optical fiber module 102 according to the comparative example comprises the optical fiber 111 and the tubular sleeve 120, which covers an outer circumferential surface in the end section 111c of the optical fiber 111. The outer circumferential surface of the optical fiber 111 and the inner circumferential surface of the sleeve 120 are bonded together by the epoxy adhesive 130. As described above, the problem is that the epoxy adhesive 130 emits light when irradiated with laser light emitted by the light source element 151.

[0019] Furthermore, the light emission of the epoxy adhesive 130 reduces the accuracy of detecting the presence / absence of an interruption in the optical fiber 111 in the lighting device 101. This is shown with reference to the Fig. 3A and Fig. 3B described.

[0020] The Fig. Figure 3A is a diagram showing a spectrum of optical feedback detected by the optical feedback sensor 156 in the lighting device. Fig. Figure 3A shows the optical feedback spectrum when the wavelength converter 160 is removed from the illumination device, creating a pseudo-interrupted state of the optical fiber 111 instead of a state where the wavelength converter 160 is mounted on the illumination device.

[0021] As shown in the drawing, the optical feedback includes light L1, which returns to the core of the optical fiber 111 after the arrival of laser light emitted by the light source element 151, and light emission from the core; light L2, which returns to the sleeve 120 after the arrival of laser light emitted by the light source element 151, and light emission from the sleeve 120; and light L3, which returns to the epoxy adhesive 130 located between the optical fiber 111 and the sleeve 120 after the emission of laser light by the light source element 151, and light emission from the epoxy adhesive 130.In the spectrum of this optical feedback, the light L1 returning from the optical fiber 111 and the light L2 returning from the sleeve 120 each appear as a steep and sharp waveform, while the light L3 returning from the epoxy adhesive 130 has a low intensity over wavelengths in the range of 500 nm to 700 nm and appears as a broad waveform.

[0022] The Fig. Figure 3B is a diagram showing the spectrum of light emitted by an epoxy resin alone. As shown in the diagram, the spectrum of light emitted by the epoxy resin alone exhibits a broad waveform over wavelengths in the range of 500 nm to 700 nm.

[0023] The majority of the laser light emitted by the light source element 151 is emitted to the end surface 111b of the optical fiber 111. The remaining portion of the laser light, which corresponds specifically to the lower part of the laser light when considering the light intensity distribution, is also emitted to the epoxy adhesive 130 located on the outer circumference of the optical fiber 111. This causes the epoxy adhesive 130 to emit light as shown in the spectrum described in the Fig. 3B is shown. The spectrum of light emitted by the epoxy resin alone, which is in the Fig. As shown in Figure 3B, there is a region that overlaps the spectrum of the light returning from the wavelength converter 160 (predominantly at a wavelength of 500 nm to 700 nm). This makes it difficult for the optical feedback sensor 156 to distinguish the light emitted by the epoxy adhesive 130 from the light returning from the wavelength converter 160. Therefore, the illumination device 101, as shown in the comparative example, has a problem in that the accuracy of detecting the presence / absence of a break in the optical fiber 111 is reduced.

[0024] In contrast, the inventors of the present invention have verified that the light emission of the adhesive can be suppressed by using a silicone resin adhesive instead of the epoxy adhesive 130.

[0025] The Fig. Figure 4 is a diagram showing the results of an accelerated high-temperature aging test performed on the optical fiber module. The abscissa in the Fig. 4 is the cumulative time of high-temperature storage of the optical fiber module and the ordinate in the Fig. 4 is the output voltage of the optical feedback sensor. In the Fig. 4 The output voltage of the optical feedback sensor was measured in the state in which the wavelength transducer 160 was removed from the lighting device, instead of the state in which the wavelength transducer 160 was mounted on the lighting device.

[0026] In this test, four epoxy adhesives, made from epoxy resins A, B, C, and D, were prepared as bonding agents to the optical fiber and the sleeve. An accelerated aging test at 150 °C was performed on the optical fiber modules containing epoxy resins A and C, and an accelerated aging test at 180 °C was performed on the optical fiber modules containing epoxy resins B and D. An accelerated aging test at 180 °C was also performed on the optical fiber module containing a silicone resin adhesive.

[0027] As it is in the Fig. As shown in Figure 4, in the optical fiber modules containing epoxy resins, a longer cumulative high-temperature storage time leads to a higher output voltage of the optical feedback sensor, regardless of the type of epoxy resin. In contrast, in the optical fiber module containing a silicone resin resin, the output voltage of the optical feedback sensor does not change significantly even when the cumulative high-temperature storage time is extended. This is because the silicone resin has a higher transmittance to laser light than the epoxy resin. The output voltage of the optical feedback sensor increases in the case of the epoxy resin because exposure to a high-temperature environment accelerates its discoloration, resulting in increased absorption of laser light and increased intensity of emission light.

[0028] As described above, when the optical fiber is bonded to the sleeve via the silicone resin, light emission from the silicone resin acting as the adhesive can be suppressed because the silicone resin hardly absorbs laser light, even when irradiated with it. Excessive temperature increases of the silicone resin acting as the adhesive beyond what is necessary can also be suppressed, since the silicone resin hardly absorbs laser light.

[0029] The present inventors have verified that the strength of the fixation of the optical fiber to the sleeve can be increased by connecting the optical fiber and the sleeve from a large number of types of silicone resins by a silicone resin that contains siloxane bonds at crosslinking points.

[0030] The Fig. Figure 5 is a diagram showing a silicone resin used as an adhesive for the optical fiber module. (a) in the Fig. 5 presents a comparative example and (b) in the Fig. 5 presents an example in accordance with the present revelation.

[0031] The silicone resin in the comparison example has polymer carbon atoms before a crosslinking reaction and exhibits carbon-carbon bonds (CC bonds) at its crosslinking points after the crosslinking reaction. In contrast, the silicone resin in the example has polymer carbon atoms before the crosslinking reaction and no carbon-carbon bonds at its crosslinking points after the crosslinking reaction, and each crosslinking point is composed of a siloxane bond (Si-O-Si). Since the siloxane bond has a higher bond energy than that of the carbon-carbon bond, the silicone resin in the example is generally more heat-resistant than the silicone resin in the comparison example and exhibits greater hardness, i.e., higher mechanical strength, than the silicone resin in the comparison example.Furthermore, the silicone resin in the example has a greater number of crosslinking points per unit volume than the comparison example, which reduces the freedom of the main chains. Consequently, the silicone resin in the example exhibits increased mechanical strength compared to the silicone resin in the comparison example.

[0032] The Fig. Figure 6 is a diagram showing the presence / absence of damage to an end surface of the optical fiber module. (a) of Fig. 6 presents a comparative example and (b) of Fig. Figure 6 is an example.

[0033] The drawing shows an image after polishing the end surface of the optical fiber module using a polishing machine. While the end surface of the optical fiber in the comparison example is partially damaged, the end surface of the optical fiber in the example shows no damage. This is assumed to be due to the higher mechanical strength of the silicone resin in the example compared to the comparison example, thus providing greater strength in fixing the optical fiber to the sleeve.

[0034] Consequently, a reduction in strength during fiber optic fixation can be suppressed by using a silicone resin containing siloxane bonds at crosslinking points as the silicone resin bonding the fiber optic cable and the ferrule. This can prevent damage to the end surface of the fiber optic module.

[0035] Embodiments according to the present disclosure are described below with reference to the drawings and the like. The embodiments described below show specific examples of the present disclosure.

[0036] The drawings are schematic views and are not always strictly accurate. Identical reference symbols are assigned to essentially identical configurations in the drawings, and repetition of their descriptions may be omitted or simplified in some cases. [Design options][1. Construction of the lighting device]

[0037] The construction of the lighting device according to one embodiment is described below with reference to the Fig. 7 described.

[0038] The Fig. Figure 7 is a schematic view showing the lighting device 1 according to one embodiment.

[0039] The illumination device 1 is a device that converts the wavelength of laser light and emits illumination light. As shown in the drawing, the illumination device 1 comprises a light source device 50 that emits laser light, an optical fiber module 2, and a wavelength converter 60.

[0040] The optical fiber module 2 is a light transmission medium that guides the laser light emitted by the light source device 50 and transmits the laser light to the wavelength converter 60. The optical fiber module 2 comprises an optical fiber 11 containing a glass component and a tubular sleeve 20 that covers the outer circumferential surface in the end section 11c of the optical fiber 11. The optical fiber 11 comprises a core through which the laser light propagates and a sheath arranged around the core. The end section of the optical fiber module 2 comprises an end surface 2b that is irradiated with laser light emitted by the light source device 50.

[0041] The wavelength converter 60 is a device that converts the laser light emitted by the optical fiber module 2 into light of a different wavelength and emits the resulting light. The wavelength converter 60 generates fluorescence by irradiating it with laser light as excitation light and scatters and emits light that has a plurality of wavelengths and is visible as a whole, for example, as white. This emitted light is used as illumination light.

[0042] The light source device 50 comprises a light source element 51, a filter 52, a dichroic mirror 53, a converging lens 54, a filter 55, and an optical feedback sensor 56. The light source device 50 comprises the light source element 51, the filter 52, the dichroic mirror 53, the converging lens 54, the filter 55, and the housing 59 in the form of a box that accommodates the optical feedback sensor 56.

[0043] A socket 58, fitted into the sleeve 20, is arranged on an outer wall of the housing 59. The optical fiber module 2 is detachably attached to the housing 59 by means of the socket 58.

[0044] The light source element 51 is a semiconductor laser element that emits laser light with a wavelength corresponding to a blue-violet to blue color (wavelength: 430 nm or more and 490 nm or less).

[0045] Filter 52 is a bandpass filter that transmits light from the light source element 51 with a laser oscillation wavelength. Filter 52 allows light emitted by the light source element 51 with a wavelength corresponding to a blue-violet to blue color to pass through.

[0046] The dichroic mirror 53 is a mirror that reflects light with a specific wavelength and transmits light with a wavelength different from that wavelength. The dichroic mirror 53 reflects the light with a wavelength that has passed through the filter 52 and transmits the light with a wavelength emitted by the wavelength converter 60.

[0047] The converging lens 54 is a lens that directs laser light into the optical fiber module 2. The converging lens 54 is arranged between the dichroic mirror 53 and the optical fiber module 2. The converging lens 54 directs the laser light, which is reflected by the dichroic mirror 53, to the end surface of the optical fiber 11 and into one end of the optical fiber module 2. The laser light, which has been introduced into the optical fiber module 2, is transmitted through the optical fiber 11, is emitted from the other end of the optical fiber 11, and is introduced into the wavelength converter 60.

[0048] Filter 55 is a bandpass or longpass filter that transmits light with a wavelength within a specified range. Of the light with a wavelength emitted by the wavelength converter 60, filter 55 allows only the light passing through the optical fiber module 2, the converging lens 54, and the dichroic mirror 53 to pass through.

[0049] The optical feedback sensor 56 is a sensor for detecting the presence or absence of an interruption in the optical fiber 11. In the light emitted by the wavelength converter 60, the optical feedback sensor 56 detects the optical feedback returning from the optical fiber module 2 through the filter 55. The illumination device 1 includes a processor (not shown) configured with a program and a CPU that executes the program. The program determines that the optical fiber 11 is uninterrupted when the optical feedback is detected at an intensity within a predetermined range, and determines that the optical fiber 11 is uninterrupted when the optical feedback is detected at an intensity outside the predetermined range.

[0050] According to the lighting device 1, the illumination light can be emitted to a location different from the location of the light source device 50 using the optical fiber 11. Since the presence or absence of an interruption in the optical fiber 11 can be determined using the optical feedback sensor 56, faults in the lighting device 1 can be detected at an early stage. [2. Structure of the optical fiber module]

[0051] Next, the structure of the optical fiber module 2 will be described with reference to the Fig. 8 and Fig. 9 described.

[0052] The Fig. Figure 8 is a perspective view showing the optical fiber module 2. Fig. Figure 9 shows a front view and a cross-sectional view of the optical fiber module 2.

[0053] As it is in the Fig. 8 and Fig. As shown in Figure 9, the optical fiber module 2 comprises the optical fiber cable 10 and the sleeve 20, which is tubular.

[0054] The optical fiber cable 10 is formed with the optical fiber 11, which contains a glass component, and the coating material 12, which covers the optical fiber 11. The optical fiber 11 has, for example, a diameter of 100 µm or more and 1000 µm or less. The optical fiber 11 has, for example, a length of 1 m or more and 100 m or less.

[0055] As it is in the Fig. As shown in Figure 9, the optical fiber 11 has an outer circumferential surface 11a, which is a side surface, and an end surface 11b orthogonal to the fiber axis F1 of the optical fiber 11. The end surface 11b forms part of the end surface 2b of the optical fiber module 2. The coating material 12 is removed from the distal end 11c1 of the end section 11c of the optical fiber 11, exposing the outer circumferential surface 11a. The end 11c of the optical fiber 11 with the exposed distal end 11c1 is inserted into the sleeve 20. Although an example in which the end surface 11b of the optical fiber 11 is orthogonal to the fiber axis F1 is shown in the preceding description, the arrangement is not limited to this. For example, the end surface 11b can be inclined to the fiber axis F1 at an angle of 0° or more and 10° or less.

[0056] The sleeve 20 covers the outer circumferential surface 11a in the end section 11c of the optical fiber 11. The sleeve 20 has an inner circumferential surface 20a, which is an inner side surface, and an end surface 20b, which is orthogonal to the fiber axis F1. The end surface 20b forms part of the end surface 2b of the optical fiber module 2. The end surface 20b of the sleeve 20 and the end surface 11b of the optical fiber 11 are polished surfaces, formed simultaneously using a polishing device or the like, and are flush with each other.

[0057] The sleeve 20 comprises a sleeve body 21 and a flange 22 into which the sleeve body 21 is pressed.

[0058] The sleeve body 21 is a cylindrical element and has a through-hole 21a with a diameter larger than that of the optical fiber 11. The inner circumferential surface of the through-hole 21a forms part of the inner circumferential surface 20a of the sleeve 20. The distal end 11c1 of the end section 11c of the optical fiber 11 is inserted into the through-hole 21a. The sleeve body 21 is, for example, made of a calcined ceramic body made of zirconium oxide.

[0059] The flange 22 is a cylindrical element with a rim and has a through-hole 22a with a diameter larger than that of the coating material 12. The inner circumferential surface of the through-hole 22a forms part of the inner circumferential surface 20a of the sleeve 20. A section of the end 11c of the optical fiber 11, excluding the distal end 11c1 (i.e., a section covered with the coating material 12), is inserted into the through-hole 22a. The flange 22 is made of a metallic material, such as stainless steel.

[0060] Both the sleeve body 21 and the flange 22 can be made of stainless steel. In this case, the sleeve 20 has a structure in which the sleeve body 21 and the flange 22 are integrated and made of stainless steel.

[0061] In the optical fiber module 2 of the lighting device 1 according to the present embodiment, the outer circumferential surface 11a of the optical fiber 11 and the inner circumferential surface 20a of the sleeve 20 are connected by the silicone resin 30, which contains siloxane bonds instead of carbon-carbon bonds at its crosslinking points.

[0062] In particular, the distal end 11c1 of the end section 11c of the optical fiber 11 and the through-hole 21a of the sleeve body 21 are connected by the aforementioned silicone resin 30. The section of the end section 11c of the optical fiber 11, excluding the distal end 11c1, and the through-hole 22a of the flange 22 are connected by the aforementioned silicone resin 30. In other words, an adhesive layer made of the aforementioned silicone resin 30 is arranged between the optical fiber 11 and the sleeve 20. The thickness of the adhesive layer near the end surface is, for example, 10 µm or less. This adhesive layer has an end surface that connects the end surface 11b of the optical fiber 11 flush with the end surface 20b of the sleeve 20.

[0063] By connecting the optical fiber 11 to the sleeve 20 using the silicone resin 30 described above, an increase in temperature and light emission can be suppressed even when the silicone resin 30, located between the optical fiber 11 and the sleeve 20, is irradiated with laser light, since the silicone resin 30 hardly absorbs laser light. Because the light emission of the silicone resin 30 can be suppressed, a reduction in the accuracy of detecting the presence or absence of an interruption in the optical fiber 11 in the illumination device 1 can be prevented.

[0064] Furthermore, the heat resistance and mechanical strength of the silicone resin 30 can be improved because the silicone resin 30 is made from a resin containing siloxane bonds at its crosslinking points and lacking carbon-carbon bonds at its crosslinking point. Accordingly, for example, the strength when fixing the optical fiber 11 to the sleeve 20 can be improved, and damage to the end surface 11b can be suppressed if the end surface 11b of the optical fiber 11 is polished. [3. Method for manufacturing an optical fiber module]

[0065] Next, a method for manufacturing an optical fiber module 2 is described.

[0066] The Fig. Figure 10 is a flowchart showing a process for manufacturing the optical fiber module 2.

[0067] First, a liquid silicone resin with polymer carbon atoms is filled between the outer circumferential surface 11a of the optical fiber 11 and the inner circumferential surface 20a of the sleeve 20 (step S11). The filling of the liquid silicone resin is implemented, for example, by applying the liquid silicone resin to at least one of the outer circumferential surfaces 11a in the end section 11c of the optical fiber 11 and the inner circumferential surface 20a of the sleeve 20, and then inserting the end section 11c of the optical fiber 11 into the inner circumferential surface 20a of the sleeve 20. Alternatively, filling is implemented by inserting the end section 11c of the optical fiber 11 into the inner circumferential surface 20a of the sleeve 20 and then injecting a liquid silicone resin with a suitable viscosity between the outer circumferential surface 11a in the end section 11c of the optical fiber 11 and the inner circumferential surface 20a of the sleeve 20.

[0068] The polymer carbon atoms represent an alkoxy group, such as CH3CH2OH, and exist in the form of a reactive group in the liquid silicone resin before heat curing of the liquid silicone resin (see the structure of the starting material polymer in (b) in the Fig. 5) Examples of liquid silicone resin include polysilsesquioxanes (SR series) manufactured by Konishi Chemical Inc. Co., Ltd.

[0069] Next, the liquid silicone resin is heated to a temperature of 140 °C or higher to accelerate the crosslinking reaction, thereby curing the liquid silicone resin (step S12). The heating temperature is preferably 140 °C or higher and 210 °C or lower. Upon heating, the polymer carbon-derived product generated during the crosslinking reaction evaporates and is removed from the silicone resin. As a result, the crosslink points of the silicone resin 30, which connects the optical fiber 11 and the sleeve 20, are composed only of siloxane bonds, and the main chains (the main chains excluding side chains) of the silicone resin 30 have a carbon-carbon bond-free structure (cf. the product generated during the crosslinking reaction in (b) in the Fig.5 is generated). It should be noted that silicone resin 30 is also referred to as condensation silicone resin. Condensation silicone resin is a resin polycondensed by a dealcoholization or dehydration reaction between a hydroxyl group bonded to a silicon atom and an alkoxy or hydroxyl group bonded to another silicon atom. Although an example has been shown in which the liquid silicone resin is heated to a temperature of 140 °C or higher, a preparative heating step at 140 °C or less may be included before a main heating at 140 °C or higher to remove the solvent from the silicone resin.

[0070] Next, the end surface 11b of the optical fiber 11 and the end surface 20b of the sleeve 20 are simultaneously polished using a polishing device (step S13). This creates a polished surface where the end surfaces 11b and 20b are flush. These steps S11 to S13 produce the optical fiber module 2.

[0071] As described above, the liquid silicone resin is cured by heating, bonding the optical fiber 11 and the sleeve 20 with the silicone resin 30, which has no carbon-carbon bonds in its main chains. This prevents a reduction in strength when fixing the optical fiber 11 to the sleeve 20 and also prevents damage to the end surface 11b of the optical fiber 11 during polishing in step S13. [4. Effects]

[0072] The optical fiber module 2 of the lighting device according to the present embodiment comprises an optical fiber 11 containing a glass component and a sleeve 20, which is tubular and covers the outer circumferential surface 11a in the end section 11c of the optical fiber 11. The outer circumferential surface 11a of the optical fiber 11 and the inner circumferential surface 20a of the sleeve 20 are connected by the silicone resin 30, which contains siloxane bonds at its crosslinking points.

[0073] By connecting the optical fiber 11 to the sleeve 20 with the silicone resin 30, as described above, light emission from the silicone resin 30 acting as an adhesive can be suppressed even when the silicone resin 30, located between the optical fiber 11 and the sleeve 20, is irradiated with laser light, since the silicone resin 30 hardly absorbs laser light. Because the silicone resin 30 hardly absorbs laser light, an excessive increase in the temperature of the silicone resin 30 acting as an adhesive beyond what is necessary can be suppressed.

[0074] The heat resistance and mechanical strength of the silicone resin 30 can be increased because the silicone resin 30 is made from a resin containing siloxane bonds at its crosslinking points. Accordingly, the strength when fixing the optical fiber 11 to the sleeve 20 can be increased, and damage to the end surface 11b can be suppressed, for example, when the end surface 11b of the optical fiber 11 is polished.

[0075] The crosslinking points of the silicone resin 30 can only be composed of siloxane bonds.

[0076] Accordingly, the strength of fixing the optical fiber 11 to the sleeve 20 can be increased and damage to the end surface 11b can be suppressed, for example by polishing the end surface 11b of the optical fiber 11.

[0077] Furthermore, the silicone resin 30 does not need to contain carbon-carbon bonds at its crosslinking points.

[0078] Accordingly, the strength of fixing the optical fiber 11 to the sleeve 20 can be increased and damage to the end surface 11b can be suppressed, for example by polishing the end surface 11b of the optical fiber 11.

[0079] Furthermore, the optical fiber 11 and the sleeve 20 can have end surfaces 11b and 20b that are flush with each other.

[0080] Accordingly, the end section 11c of the optical fiber module 2 can be fixed using the sleeve 20 and the laser light can be introduced more efficiently from the end surface 11b of the optical fiber 11.

[0081] The lighting device 1 according to the present embodiment comprises a light source element 51 which emits laser light, an optical fiber module 2 into which the laser light is introduced, and a wavelength converter 60 which converts the laser light introduced through the optical fiber module 2 into light with a different wavelength.

[0082] In the lighting device 1, which includes the aforementioned optical fiber module 2, light emission from the silicone resin 30, acting as an adhesive, can be suppressed even when the silicone resin 30, located between the optical fiber 11 and the sleeve 20, is irradiated with laser light, since the silicone resin 30 absorbs very little laser light. Furthermore, an excessive increase in the temperature of the silicone resin 30, acting as an adhesive, can be suppressed beyond what is necessary, since the silicone resin 30 absorbs very little laser light.

[0083] Furthermore, the illumination device 1 can also include a converging lens 54 that converges laser light to the end surface 11b of the optical fiber 11.

[0084] Accordingly, the amount of laser light emitted to the silicone resin 30 can be reduced, since a large part of the laser light can be introduced into the end surface 11b of the optical fiber 11 using the converging lens 54. This allows the light emission of the silicone resin 30 to be suppressed.

[0085] Furthermore, the lighting device 1 can also include an optical feedback sensor 56 which detects the light returning through the optical fiber module 2 from the light emitted by the wavelength converter 60.

[0086] Accordingly, a reduction in the accuracy of detecting the presence / absence of an interruption of the optical fiber 11 in the illumination device 1 can be suppressed even if the silicone resin 30, which is located between the optical fiber 11 and the sleeve 20, is irradiated with laser light, since light emission from the silicone resin 30 can be suppressed.

[0087] The laser light can have a wavelength of 430 nm or more and 490 nm or less.

[0088] Since the lighting device 1 includes the optical fiber module 2 in which the silicone resin 30 with a transmittance for laser light with a wavelength of 430 nm or more and 490 nm or less is used as an adhesive, light emission from the silicone resin 30 can be suppressed even when the silicone resin 30 is irradiated with the laser light.

[0089] The method for manufacturing the optical fiber module 2 according to the present embodiment is a method for manufacturing the optical fiber module 2, comprising the optical fiber 11, which contains a glass component, and the sleeve 20, which is tubular and covers the outer circumferential surface 11a in the end section 11c of the optical fiber 11, wherein the method comprises filling a liquid silicone resin with polymer carbon atoms between the outer circumferential surface 11a of the optical fiber 11 and the inner circumferential surface 20a of the sleeve 20; curing the liquid silicone resin by heating at a temperature of 140 °C or higher; and simultaneously polishing the end surface 11b of the optical fiber 11 and the end surface 20b of the sleeve 20.

[0090] By curing the liquid silicone resin through heating, as described above, the optical fiber 11 and the sleeve 20 can be fixed by the silicone resin 30, which has no carbon-carbon bonds in its main chains. This prevents a reduction in strength when fixing the optical fiber 11 to the sleeve 20 and prevents damage to the end surface 11b of the optical fiber 11 during polishing. [Other embodiments]

[0091] Although the optical fiber module has been described above on the basis of the embodiments according to the present disclosure, the present disclosure is not limited to these embodiments.

[0092] For example, although the preceding description shows an example in which the liquid silicone resin contains polymer carbon atoms, the liquid silicone resin is not limited to this. The liquid silicone resin can be a liquid silicone resin that has a hydroxyl group instead of polymer carbon atoms.

[0093] Although a situation has been described above in which the presence / absence of an interruption in the optical fiber 11 is determined when the light source element 51 emits laser light as excitation light, determining the presence / absence of an interruption is not limited to such a situation. For example, the illumination device 1 can determine the presence / absence of an interruption in the optical fiber 11 by attempting to emit light with a lower luminous intensity and a wider spectral bandwidth than that of excitation light before the light source element 51 emits the excitation light, and by detecting whether this light returns normally. According to the present embodiment, light emission from the adhesive can also be suppressed in a situation where the light is experimentally emitted. [List of reference symbols] 1 lighting device 2 fiber optic modules 2b Final surface 11 Optical fiber 11a Outer circumferential surface 11b Final surface 11c Final Section 20 sleeve 20a Inner circumferential surface 20b Final surface 30 silicone resin 51 light source element 54 Converging lens 56 Optical feedback sensor 60 wavelength converters F1 fiber axis

Claims

[1] Lighting device (1) comprising: a light source element (51) that emits laser light; an optical fiber module (2) into which the laser light is introduced; and a wavelength converter (60) which converts the laser light passed through the optical fiber module (2) into light with a different wavelength, wherein the optical fiber module (2) comprises: an optical fiber (11) containing a glass component; and a sleeve (20) which is tubular and covers an outer peripheral surface (11a) in an end portion (11c) of the optical fiber (11), wherein the outer peripheral surface (11a) of the optical fiber (11) and an inner peripheral surface (20a) of the sleeve (20) are bonded by a silicone resin (30) containing siloxane bonds at crosslinking points, and wherein the optical fiber (11) and the silicone resin (30) are irradiated with laser light when the laser light is introduced into the optical fiber module (2). [2] Lighting device (1) according to claim 1, further comprising: a converging lens (54) which converges the laser light onto an end surface (11b) of the optical fiber (11). [3] Lighting device (1) according to claim 1 or 2, further comprising: an optical feedback sensor (56) which detects light returning through the optical fiber module (2) from the light emitted by the wavelength converter (60). [4] The lighting device (1) according to any one of claims 1 to 3, wherein the laser light has a wavelength of 430 nm or more and 490 nm or less. [5] Lighting device (1) according to one of claims 1 to 4, wherein the crosslinking points of the silicone resin (30) are composed only of the siloxane bonds. [6] Lighting device (1) according to one of claims 1 to 5, wherein the silicone resin (30) does not contain a carbon-carbon bond in main chains. [7] Lighting device (1) according to one of claims 1 to 6, wherein the optical fiber (11) and the sleeve (20) have end surfaces (2b, 11b, 20b) which are flush with each other. [8] A method for manufacturing an optical fiber module (2) comprising an optical fiber (11) containing a glass component and a sleeve (20) which is tubular and covers an outer peripheral surface (11a) in an end portion (11c) of the optical fiber (11), the method comprising: Filling a liquid silicone resin (30) comprising polymer carbon atoms between the outer peripheral surface (11a) of the optical fiber (11) and an inner peripheral surface (20a) of the sleeve (20); Curing the liquid silicone resin (30) by heating at a temperature of 140 °C or higher to form a silicone resin (30) containing siloxane bonds at crosslinking points; and simultaneously polishing an end surface (11b) of the optical fiber (11) and an end surface (20b) of the sleeve (20).

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