Lighting device

Abstract

Lighting device (1, 201), comprising: a laser light source (42) that emits laser light; a wavelength converter that converts a wavelength of the laser light and emits wavelength-converted light; a first lens (46) which focuses the wavelength-converted light emitted by the wavelength converter (44); a second lens (47), which further focuses the wavelength-modified light from the first lens (46); and a linear optical fiber (6, 6b, 206, 206b, 306, 306b) which is elongated and guides the wavelength-modified light from the second lens (47) which is introduced longitudinally through an end face (61a, 63a), wherein the linear optical fiber (6, 6b, 206, 206b, 306, 306b) comprises a side surface (62, 262, 362) which emits the wavelength-modified light from the linear optical fiber (6, 6b, 206, 206b, 306, 306b) which is guided through the linear optical fiber (6, 6b, 206, 206b, 306, 306b), and the proportion of wavelength-modified light emitted through the side surface (62, 262, 362) gradually increases with increasing optical path length in the linear optical fiber (6, 6b, 206, 206b, 306, 306b).

Description

[Technical field]

[0001] The present disclosure relates to a lighting device. [State of the art]

[0002] A conventional vehicle lamp comprising a laser light source and a light guide that transmits the laser light emitted by the laser light source is known (see, for example, patent document (PTL) 1 or patent document (PTL) 2).

[0003] Patent document PTL 2 describes a lighting device for a motor vehicle, comprising a light guide, wherein light from at least one laser light source can be coupled in via at least one coupling surface at an end face of the light guide. The light guide further comprises an output coupling surface arranged along the direction of light propagation for coupling out light, which exits the light guide at an exit surface arranged along the direction of light propagation, thereby overriding the total internal reflection condition. [Document List][Patent Document]

[0004] [PTL 1] Japanese unexamined patent application with publication number JP 2014-17 060 A; PTL 2: DE 10 2011 085 385 A1. [Summary of the invention][Technical problem]

[0005] Typically, the longer the optical fiber, the more inconsistent the light emission from it becomes. Therefore, there is a need for a lighting device that increases the uniformity of the light emitted by the optical fiber.

[0006] In this respect, it is an objective of the present disclosure to provide an efficient lighting device that can emit very uniform light. [Solution to the problem]

[0007] To solve the problem described above, a linear lighting device comprising the features specified in claim 1 or claim 10 is included. [Advantageous effects of the invention]

[0008] With the present disclosure, very uniform light can be emitted. [Brief description of the drawings] Fig. Figure 1 is a perspective view of a linear lighting device according to embodiment 1; Fig. Figure 2 is an enlarged cross-sectional view of line II-II in the Fig. 1, which shows a light source module in the linear lighting device according to embodiment 1; Fig. Figure 3A shows a top view and a cross-sectional view of a linear light guide in the linear lighting device according to embodiment 1; Fig. Figure 3B shows a cross-sectional view of the linear light guide in the linear lighting device according to embodiment 1; Fig. Figure 4A shows a cross-sectional view of a linear light guide in a linear lighting device according to a variation of embodiment 1; Fig. Figure 4B shows a cross-sectional view of a linear light guide in a linear lighting device according to a variation of embodiment 1; Fig. Figure 5 is a perspective view of a linear lighting device according to embodiment 2; Fig. Figure 6A shows a top view and a cross-sectional view of a linear light guide in the linear lighting device according to embodiment 2; Fig. Figure 6B shows a cross-sectional view of the linear light guide in the linear lighting device according to embodiment 2; Fig. Figure 7 shows light emitted from linear light guides in the linear lighting devices; Fig. Figure 8A shows a cross-sectional view of a linear light guide in a linear lighting device according to a variation of embodiment 2; and Fig. Figure 8B shows a cross-sectional view of a linear light guide in a linear lighting device according to a variation of embodiment 2. [Description of embodiments]

[0009] Embodiments are described below with reference to the drawings. The embodiments described below each represent a preferred, specific example of the present disclosure. The numerical values, shapes, materials, elements, arrangement, and connection of the elements, etc., specified in the following embodiments are merely examples and are therefore not intended to limit the present disclosure. Therefore, those elements in the following embodiments that are not specified in any of the broadest independent claims are described as optional elements.

[0010] Furthermore, in the case of "roughly the same", "roughly" means not only exactly the same, but also what would be considered to be essentially the same.

[0011] It should be noted that the drawings are schematic and not necessarily exact representations. Additionally, reference symbols indicate corresponding elements in the drawings, and repeated descriptions of these elements have been omitted or simplified.

[0012] The following describes embodiments of a linear lighting device according to the present disclosure. EXECUTION FORM 1 (Configuration)

[0013] The Fig. Figure 1 is a perspective view of a linear lighting device 1 according to embodiment 1.

[0014] In the Fig. Figure 1 shows the X, Y, and Z directions. The direction in which the laser light source 42 emits light corresponds to the positive X-axis direction, the direction towards the top of the drawing from the linear light guide 6 corresponds to the positive Y-axis direction, and the direction towards the ceiling on which the linear lighting device 1 is installed corresponds to the positive Z-axis direction. The Fig. The directions shown in section 1 correspond to those in the Fig. 2 directions shown. This also applies to the drawings according to the Fig. 2, with the exception of drawings in which the X, Y and Z directions are not specified.

[0015] As it is in the Fig. As shown in Figure 1, the linear lighting device 1 is a linear light that is elongated along the X-axis and is installed on a part of a building, such as the ceiling or a wall. The linear lighting device 1 is an example of the lighting device. The linear lighting device 1 comprises a housing 3, a light source module 4, a linear light guide 6, a reflector plate 7, and a translucent plate 8.

[0016] The housing 3 is a box elongated along the X-axis. The housing 3 contains the light source module 4, the linear light guide 6, the reflective plate 7, and the translucent plate 8. The housing 3 has an opening 3a on its surface, located in the negative Z-axis direction. Wavelength-modified light emitted through the linear light guide 6 passes through the opening 3a.

[0017] The Fig. Figure 2 is an enlarged cross-sectional view of line II-II in the Fig. 1, which shows the light source module 4 in the linear lighting device 1 according to embodiment 1.

[0018] As it is in the Fig. As shown in Figure 2, the light source module 4 is a device that emits laser light. The light source module 4 comprises a housing 41, a laser light source 42, a substrate 43 on which the laser light source 42 is mounted, a phosphor body 44, a heat sink 45, a first lens 46, and a second lens 47.

[0019] The housing 41 is a box containing the laser light source 42, the substrate 43, the phosphor body 44, the heat sink 45, the first lens 46, the second lens 47, and one end of the linear light guide 6 in the longitudinal direction. Within the housing 41, the following components are arranged in the specified order in the positive X-axis direction starting from the heat sink 45: the substrate 43, the laser light source 42, the phosphor body 44, the first lens 46, the second lens 47, and the linear light guide 6. The laser light source 42, the substrate 43, the phosphor body 44, the heat sink 45, the first lens 46, and the second lens 47 are mounted within the housing 41, for example, using a fastening device.

[0020] The laser light source 42 is a light source that emits laser light. The laser light source 42 emits laser light to the entrance surface 61, which is the end surface in the longitudinal direction at the end of the negative x-axis direction of the linear optical fiber 6. The laser light is excitation light that excites the phosphor in the phosphor body 44. For example, the wavelength of the laser light extends from the blue wavelength band to the violet wavelength band and can cause the phosphor body 44 to emit wavelength-transformed light.

[0021] The linear illumination device 1 according to this embodiment is an optical system in which laser light emitted by the laser light source 42 is converted into wavelength-modified light by the phosphor body 44 and then introduced into the linear optical fiber 6. In such an optical system, it is known that the quantity referred to as the "light conductance" is preserved as long as the light is not, for example, scattered. The light conductance is defined as the product of the emitting surface area of ​​the laser light source 42 and the aperture angle of the laser light emitted by the laser light source 42. Accordingly, the light conductance is a measure of the ability of the laser light emitted by the laser light source 42 to be introduced through the entrance surface 61, i.e., the magnitude of the ability of the linear optical fiber 6 to absorb the light it receives.For example, if the optical conductivity of the entry surface 61 in the linear optical guide 6 is smaller than the optical conductivity of the laser light source 42, the linear optical guide 6 cannot absorb all the laser light emitted by the laser light source 42, resulting in some loss.

[0022] Laser light, which has a small emitting surface area and is highly directional, exhibits a low optical conductivity. Accordingly, by emitting laser light into the phosphor body 44, fluorescent light with a low optical conductivity can be emitted from the phosphor body 44. It is therefore possible to improve the efficiency of the combination of laser light source 42 and linear light guide 6.

[0023] The emission of laser light from the laser light source 42 is controlled by a control device. The laser light source 42 can be implemented as a semiconductor laser that emits laser light whose wavelength range extends from the ultraviolet band to the blue band; that is, it emits light with a wavelength shorter than blue laser light. The laser light source 42 can also be implemented, for example, as an InGaN laser diode or an AllnGaN laser diode.

[0024] It should be noted that the laser light emitted by the laser light source 42 can be, for example, light emitted by an LED, as long as the light can excite a phosphor. Although a single laser light source 42 is used as an example, two or more laser light sources 42 can be used.

[0025] The phosphor body 44 is arranged between the laser light source 42 and the linear light guide 6 and converts the wavelength of the laser light so that wavelength-converted light is emitted. In particular, the phosphor body 44 is arranged between the laser light source 42 and the first lens 46. The phosphor body 44 is fixed within the housing 3 such that it lies on the optical axis of the laser light emitted by the laser light source 42.

[0026] The phosphor body 44 is, for example, a fluorescent wheel. The phosphor body 44 rotates on an axis of rotation that is parallel to the optical axis of the laser light. The phosphor body 44 is rotatably driven by a motor. In this embodiment, the phosphor body 44 is approximately perpendicular to the optical axis of the laser light emitted by the laser light source 42.

[0027] The phosphor body 44 generates wavelength-converted light from the laser light emitted by the laser light source 42. Specifically, the phosphor body 44 converts the laser light into predetermined wavelength-converted light. The phosphor body 44 comprises a phosphor that is a wavelength converter and emits wavelength-converted light when irradiated with the laser light. In other words, the wavelength-converted light is fluorescent light. The phosphor is, for example, a yttrium aluminum garnet (YAG) or BAM phosphor. The phosphor can be selected according to the type of laser light emitted by the laser light source 42. In this embodiment, the laser light introduced into the phosphor body 44 generates white wavelength-converted light.

[0028] The phosphor body 44 is produced by dispersing fine particles of a specified phosphor in a binder, which is a transparent material, such as a ceramic or a silicone resin. In other words, the binder is the medium that holds the phosphor of the phosphor body 44. The binder incorporated into the phosphor body 44 is not limited to a ceramic or a silicone resin; other transparent materials, such as transparent glass, can be used for the binder.

[0029] It should be noted that the phosphor can contain, for example, red, green, and blue phosphors and, as a result of excitation by excitation light, can emit red, green, and blue light. In such cases, the wavelength-converted red, green, and blue light can be mixed to obtain white light.

[0030] The phosphor body 44 can comprise a plurality of phosphors that absorb a portion of the blue laser light from the laser light source 42 and convert the wavelength of the absorbed light to produce green to yellow light. With such a phosphor body 44, for example, when the laser light source 42 emits blue laser light, the green to yellow fluorescent light emitted as a result of the phosphor body 44 absorbing a portion of the blue laser light is mixed with the blue laser light that passes through the phosphor without being absorbed, resulting in pseudo-white wavelength-converted light.

[0031] The phosphor body 44 is an example of a wavelength converter. It should be noted that a phosphor not held by a binder can also be used as a wavelength converter.

[0032] The heat sink 45 is a heat dissipation component that dissipates heat generated by the laser light source 42. On the side of the negative x-axis direction of the heat sink 45, i.e., on the side opposite the laser light source 42, fins are exposed on the housing 41.

[0033] The first lens 46 is a plano-convex lens. The first lens 46 is arranged in the housing 41 such that the planar surface of the first lens 46 is approximately perpendicular to the optical axis of the laser light source 42.

[0034] The second lens 47 is a plano-convex lens. The second lens 47 is arranged in the housing 41 such that its planar surface is approximately perpendicular to the optical axis of the laser light source 42. The convex surface of the second lens 47 faces the convex surface of the first lens 46, and the planar surface of the second lens 47 faces the entrance surface 61 of the linear optical fiber 6. The first lens 46 and the second lens 47 focus wavelength-modified light emitted by the phosphor body 44.

[0035] The Fig. Figure 3A shows a top view and a cross-sectional view of the linear light guide 6 in the linear lighting device 1 according to embodiment 1.

[0036] As it is in the Fig. 2 and the Fig. As shown in Figure 3A, the linear light guide 6 is a cylindrical, rod-shaped component made of a transparent material and is, for example, an optical fiber cable. The linear light guide 6 is fixed within the housing 3 such that it is approximately parallel to the X-axis. The elongated linear light guide 6 receives wavelength-converted light emitted by the phosphor body 44 through its entrance surface 61, which is an end surface in the longitudinal direction, and transmits the received wavelength-converted light. The linear light guide 6 is optically coupled to the laser light source 42 by means of an optical lens. It should be noted that the shape of the linear light guide 6 is not limited to a cylindrical shape; the linear light guide 6 can have any type of column shape, such as a polygonal column. In this embodiment, the linear light guide 6 has a diameter of approximately 2 mm.

[0037] The linear optical fiber 6 comprises the entrance surface 61, the first emission surface 62 and the second emission surface 63.

[0038] The entrance surface 61 is a surface through which the wavelength-modified light, generated by the phosphor body 44 upon receiving the laser light from the laser light source 42 and focused by the first lens 46 and the second lens 47, is introduced. The entrance surface 61 is directed towards the second lens 47. The entrance surface 61 is also directed towards the laser light source 42, with the first lens 46, the second lens 47, and the phosphor body 44 positioned between them.

[0039] As it is in the Fig. As shown in Figure 3A, the linear light guide 6 comprises a light emission device (included in the side surface) that emits the guided wavelength-converted light from the first emission surface 62 of the linear light guide 6. In this embodiment, the light emission device is an uneven surface structure on the first emission surface 62 of the linear light guide 6. The first emission surface 62 is the outer diameter surface of the linear light guide 6; that is, the first emission surface 62 is a side surface of the linear light guide 6 that intersects the radial direction of the linear light guide 6. Light guided through the linear light guide 6 is emitted from the first emission surface 62.

[0040] The proportion of wavelength-modified light emitted by the light-emitting device gradually increases with increasing optical path length in the linear light guide 6. The proportion of wavelength-modified light emitted by the light-emitting device gradually increases with the distance from the entrance surface 61. In other words, the density of depressions 64 or protrusions in the uneven surface structure, which is the light-emitting device, gradually increases with the distance from the entrance surface 61. In this embodiment, a plurality of depressions 64, which are incorporated into the uneven surface structure, are formed in the linear light guide 6. The density of depressions 64 formed in the first emission surface 62 gradually increases with the distance from the entrance surface 61.The depressions 64 are prisms with each of the following shapes: a circular cone, a hemisphere, a truncated circular cone, a truncated pyramid, and a pyramid. The . Fig. Figure 3B shows a cross-sectional view of the linear light guide 6b in the linear lighting device 1 according to embodiment 1. Fig. Figure 3B shows a linear optical fiber 6b which has a plurality of protrusions 64b in the uneven surface structure.

[0041] It should be noted that in this embodiment, as described in the Fig. As shown in Figure 3A, depressions 64, which are incorporated into the uneven surface structure, are formed in the first emission surface 62; however, protrusions, which are incorporated into the uneven surface structure, may be formed on the first emission surface 62. Accordingly, the uneven surface structure is not limited to depressions 64. It should be noted that the protrusions, which are incorporated into the uneven surface structure, have the inverse structure of depressions 64, and as such, a detailed description of them has been omitted.

[0042] Here, the proportion of wavelength-modified light emitted by the light emission device is defined as the proportion of the amount of light emitted in the circumferential direction from the first emission surface 62 relative to the amount of light guided through the linear light guide 6.

[0043] It should be noted that the light emission device is not fixed to an uneven surface structure and can, for example, be a light-scattering medium such as a silicone resin or silicon oxide. In such cases, the light-scattering medium can be contained within the linear light guide 6 or, alternatively, applied to the first emission surface 62. The density of the scattering medium in the linear light guide 6 gradually increases with the distance from the entrance surface 61.

[0044] It should be noted that a light scattering function can be achieved by printing a pattern of dots onto the first emission surface 62 of the linear light guide 6.

[0045] The second emission surface 63 is located at the opposite end of the linear optical fiber 6 relative to the entrance surface 61. Wavelength-modified light, which is guided through the linear optical fiber 6, is emitted from the second emission surface 63.

[0046] A laser cutting device can be used to create the depressions 64 in the base material used for the linear optical fiber 6. The laser cutting device comprises, for example, a laser emitter, a galvanic scanner, and an fθ lens. The laser from the laser emitter is emitted onto the base material used for the linear optical fiber 6 after it has been reflected by the galvanic scanner and transmitted through the fθ lens. This causes the base material used for the linear optical fiber 6 to rotate and be pressed in the axial direction. This forms depressions 64 in the first emission surface 62 of the base material used for the linear optical fiber 6.

[0047] As it is in the Fig. As shown in Figure 1, the reflecting plate 7 is a mirror that reflects the wavelength-modified light emitted through the linear optical fiber 6. The reflecting plate 7 is curved in the positive Z-axis direction. This allows the reflecting plate 7 to reflect and emit the wavelength-modified light from the linear optical fiber 6 in the negative Z-axis direction. The wavelength-modified light emitted through the linear optical fiber 6 illuminates the surrounding area. It should be noted that the reflecting plate 7 is not limited to a sheet material; the reflecting plate 7 can be a reflective film. In other words, the reflecting plate 7 is an example of a reflector.

[0048] The translucent plate 8 covers the opening 3a of the housing 3. The wavelength-modified light emitted through the linear light guide 6 passes through the translucent plate 8. The translucent plate 8 is made of a transparent material, such as acrylic or glass.

[0049] In the linear illumination device 1, configured as described above, the laser light emitted by the laser light source 42 is introduced into the phosphor body 44. The phosphor in the phosphor body 44 converts the wavelength of the laser light, producing wavelength-converted light. The wavelength-converted light emitted by the phosphor body 44 is focused by the first lens 46 and the second lens 47 and then enters the linear light guide 6 through the entrance surface 61. The wavelength-converted light is emitted by depressions 64 in the first emission surface 62 as it passes through the linear light guide 6. The density of depressions 64, or protrusions in the uneven surface structure on the first emission surface 62, gradually increases with distance from the entrance surface 61.Accordingly, the proportion of guided, wavelength-modified light extracted through the linear optical fiber 6 is greater the greater the distance from the entrance surface 61. This makes it easy to emit uniform wavelength-modified light from the first emission surface 62, characterized by reduced brightness variation. (Operating advantages)

[0050] Next, the operational advantages of the linear lighting device 1 according to this embodiment will be described.

[0051] As described above, the linear illumination device 1 according to this embodiment is elongated. The linear illumination device 1 comprises a laser light source 42 that emits laser light, a phosphor body 44 that converts the wavelength of the laser light and emits wavelength-converted light, and the linear light guide 6, which is elongated and guides the wavelength-converted light emitted by the phosphor body 44 and introduced through the entrance surface 61. The linear light guide 6 includes a light emission device that emits the guided wavelength-converted light from the first emission surface 62 of the linear light guide 6. The proportion of wavelength-converted light emitted by the light emission device gradually increases with increasing optical path length in the linear light guide 6.

[0052] As a result, the proportion of wavelength-modified light emitted by the light-emitting device gradually increases with increasing optical path length in the linear light guide 6. This makes it possible to emit a significant amount of wavelength-modified light from the first emission surface 62 at locations remote from the entrance surface 61. This enables the emission of uniform wavelength-modified light, characterized by reduced luminance variation, from the first emission surface 62; that is, it allows for the straightforward emission of light from the first emission surface 62.

[0053] Accordingly, it is possible to emit a very uniform light with the linear lighting device 1.

[0054] In the linear illumination device 1 according to this embodiment, the light emission device is an uneven surface structure defined by depressions 64 in or protrusions on the first emission surface 62 of the linear light guide 6. The density of the depressions 64 or the protrusions of the uneven surface structure gradually increases with distance from the entrance surface 61.

[0055] In this way, the density of the depressions 64 or protrusions in the uneven surface structure gradually increases with distance from the entrance surface 61. This enables a significant amount of wavelength-modified light to be emitted from depressions 64 or protrusions at locations farther from the entrance surface 61. This makes it easy to emit uniform wavelength-modified light from the first emission surface 62, which is characterized by reduced brightness variation.

[0056] In the linear illumination device 1 according to this embodiment, the light emission device is an uneven surface structure defined by depressions 64 in or protrusions on the side surface of the linear light guide 6. The depressions 64 or the protrusions in the uneven surface structure are prisms with any of the following shapes: a circular cone, a hemisphere, a truncated circular cone, a truncated pyramid, and a pyramid.

[0057] In the linear illumination device 1 according to this embodiment, the light emission device is an uneven surface structure defined by depressions 64 in or protrusions on the side surface of the linear light guide 6. In a top view of the depressions or protrusions in the uneven surface structure, each of the depressions 64 or protrusions has approximately the same inner diameter or outer diameter.

[0058] The linear illumination device 1 according to this embodiment further comprises a reflective plate 7, which reflects the wavelength-modified light emitted through the linear light guide 6; a transparent plate 8, which transmits the wavelength-modified light; and a housing 3, which accommodates the laser light source 42, the fluorescent body 44, the linear light guide 6, and the reflective plate 7, and which holds the transparent plate 8 in the opening 3a through which the wavelength-modified light passes. The reflective plate 7 is oriented in the housing 3 such that it reflects the wavelength-modified light in the direction of the opening 3a.

[0059] The linear illumination device 1 according to this embodiment is elongated. The linear illumination device 1 comprises a laser light source 42 that emits laser light, a phosphor body 44 that converts the wavelength of the laser light and emits wavelength-converted light, and a linear optical fiber 6 that is elongated and guides the wavelength-converted light emitted by the phosphor body 44 and introduced through the entrance surface 61. The linear optical fiber 6 comprises a side surface that emits the guided wavelength-converted light from the linear optical fiber 6. The proportion of wavelength-converted light emitted through the side surface gradually increases with increasing optical path length in the linear optical fiber 6. VARIATION OF EXECUTION FORM 1

[0060] The Fig. Figure 4A shows a cross-sectional view of a linear light guide 6 in the linear lighting device 1 according to a variation of embodiment 1.

[0061] In this variation, the recesses 164 differ from those of embodiment 1 in that their depth varies. Furthermore, unless otherwise specified, the linear lighting device 1 in this variation has the same configuration as in embodiment 1. Accordingly, corresponding elements have corresponding reference numerals in the drawings, and a repeated detailed description of these elements is omitted.

[0062] As it is in the Fig. As shown in Figure 4A, a plurality of depressions 164 are formed in the first emission surface 62 of the linear optical fiber 6. The depth or height of the depressions 164, or of the protrusions of the uneven surface structure, gradually increases with the distance from the entrance surface 61. In this embodiment, the depressions 164 are used. In particular, each depression 164 has the same diameter, but the depth of the depressions 164 gradually increases with the distance from the entrance surface 61.

[0063] With this configuration, the light emission device in the linear illumination device 1 according to this embodiment is an uneven surface structure defined by a plurality of depressions 164 in or protrusions on the first emission surface 62 of the linear light guide 6. The depth or height of the depressions 164 or the protrusions of the uneven surface structure gradually increases with distance from the end surface in the longitudinal direction.

[0064] In this way, the depth or height of the depressions 164 or the protrusions gradually increases with distance from the entrance surface 61. This allows a significant amount of wavelength-modified light to be emitted from the depressions 164 or protrusions at locations farther from the entrance surface 61. This makes it easy to emit uniform wavelength-modified light, characterized by reduced brightness variation, from the first emission surface 62. Fig. Figure 4B shows a cross-sectional view of the linear light guide 6b in the linear lighting device 1 according to a variation of embodiment 1. Fig. Figure 4B shows a linear light guide 6b comprising a plurality of protrusions 164b in the uneven surface structure.

[0065] These variations also achieve the other operational advantages achieved by embodiment 1. EXECUTION FORM 2

[0066] The Fig. Figure 5 is a perspective view of a linear lighting device 201 according to embodiment 2. Fig. Figure 6A shows a top view and a cross-sectional view of a linear light guide 206 in the linear lighting device 201 according to embodiment 2.

[0067] This embodiment differs from embodiment 1 in that laser light from laser light sources 42, which are arranged at both ends in the longitudinal direction of the linear light guide 206, is introduced into the linear light guide 206. Accordingly, the second emission surface 63 according to embodiment 1 corresponds to the second entry surface 63a according to this embodiment, and the first emission surface 62 according to embodiment 1 corresponds to the emission surface 262 according to this embodiment.

[0068] Furthermore, unless otherwise specified, the linear lighting device 201 according to this embodiment has the same configuration as embodiment 1 and its variations. Accordingly, corresponding elements have corresponding reference numerals in the drawings, and a repeated detailed description of these elements is omitted.

[0069] As it is in the Fig. As shown in Figure 6A, the linear lighting device 201 comprises a first light source module 4a and a second light source module 4b. The first light source module 4a and the second light source module 4b have the same configuration. Fig. Figure 6B shows a cross-sectional view of the linear light guide 206b in the linear lighting device 201 according to embodiment 2. Fig. Figure 6B shows the linear light guide 206b, which includes a plurality of protrusions 64b in the uneven surface structure.

[0070] As it is in the Fig. As shown in Figure 6A, the phosphor body 44 comprises a first phosphor body arranged between the first laser light source and the linear light guide 206, and a second phosphor body arranged between the second laser light source and the linear light guide 206.

[0071] The first light source module 4a is arranged on one side of the linear light guide 206, which is the side in the negative X-axis direction. The second light source module 4b is arranged on the other side of the linear light guide 206, which is the side in the positive X-axis direction. In other words, the first light source module 4a and the second light source module 4b are each arranged at the two ends along the longitudinal direction of the linear light guide 206.

[0072] The wavelength of the laser light emitted by the first laser light source in the first light source module 4a is converted by the first phosphor body. This first wavelength-converted light enters the linear light guide 206 through the first entrance surface 61a, which is the end surface in the longitudinal direction along the negative x-axis. The wavelength of the laser light emitted by the second laser light source in the second light source module 4b is converted by the second phosphor body. This second wavelength-converted light enters the linear light guide 206 through the second entrance surface 63a, which is the end surface in the longitudinal direction along the positive x-axis.

[0073] The density of depressions 64 or protrusions in the uneven surface structure of the linear light guide 206 gradually increases with the distance from the first entry surface 61a to the central region of the linear light guide 206 and from the second entry surface 63a to the central region of the linear light guide 206.

[0074] The linear light guide 206 is optically connected to the first light source module 4a and the second light source module 4b. In addition to the first entrance surface 61a, the linear light guide 206 comprises an emission surface 262 and a second entrance surface 63a.

[0075] The emission surface 262 is the outer diameter surface of the linear light guide 206 and intersects the radial direction of the linear light guide 206. Light passed through the linear light guide 206 is emitted from the emission surface 262.

[0076] The second entry surface 63a is the surface through which light emitted by the laser light source 42 in the second light source module 4b is introduced into the linear optical fiber 206.

[0077] The second entry surface 63a is the end surface in the longitudinal direction, which is located at the end in the positive X-axis direction of the linear optical fiber 206, which is at the opposite end of the linear optical fiber 206 relative to the first entry surface 61a. (Test results)

[0078] The Fig. Figure 7 shows light emitted by linear light guides in linear lighting devices. In the Fig. 7. Laser light sources 42 are arranged at both ends in the longitudinal direction of each linear optical fiber, as is the case in this embodiment. A 200 mm long optical fiber made of acrylic and having a refractive index of n = 1.49 was used for each of the linear optical fibers.

[0079] In the Fig. Figure 7 shows (a) a graph of the brightness of light emitted from the surface in the positive Y-axis direction of the linear optical fiber 6a in which no depressions 64 are formed, (b) shows the direction in which light is emitted from the side surface of the linear optical fiber 6a in which no depressions 64 are formed, and (c) shows the brightness distribution for a linear optical fiber 6a in which no depressions 64 are formed.

[0080] As it progresses through (a) to (c) in the Fig. As shown in Figure 7, if no depressions 64 are formed in the linear optical fiber 6a, light is emitted disproportionately in the vicinity of the laser light sources 42, and the brightness decreases with increasing distance from the entrance surfaces. This demonstrates that with such a linear optical fiber 6a, the luminance of light emitted from the emission surface is uneven.

[0081] In the Fig. Figure 7 shows (d) a graph of the brightness of light emitted from the surface in the positive y-axis direction of the linear optical fiber 6b in which uniformly spaced depressions 64 are formed, (e) shows the direction in which light is emitted from the side surface of the linear optical fiber 6b in which uniformly spaced depressions 64 are formed, and (f) shows the brightness distribution for the linear optical fiber 6b in which uniformly spaced depressions 64 are formed. In (d) to (f) in the Fig. The recesses 64 are spaced approximately 2 mm apart.

[0082] As it progresses through (d) to (f) in the Fig. As shown in Figure 7, when uniformly spaced depressions 64 are formed in the linear optical fiber 6b, light is emitted disproportionately in the vicinity of the laser light sources 42, and the brightness decreases with the distance from the entrance surfaces. With the linear optical fiber 6b configured as described above, the brightness is significantly lower compared to the linear optical fiber 6a, which is configured (a) to (c) in the Fig. 7 corresponds to a more uniform brightness, however, the brightness in the central area of ​​the linear light guide 6b is low, resulting in an unevenness in the luminance of the light emitted from the emission surface.

[0083] In the Fig. Figure 7 shows (g) a graph of the brightness of light emitted from the surface in the positive Y-axis direction of the linear light guide 206 according to this embodiment, (h) shows the direction in which light is emitted from the side surface of the linear light guide 206 according to this embodiment, and (i) shows the brightness distribution for the linear light guide 206 according to this embodiment.

[0084] As it progresses through (g) to (i) in the Fig. As shown in Figure 7, in the case of the linear light guide 206 according to this embodiment, the brightness does not decrease even at locations far from the first entry surface 61a. Compared to the linear light guides 6a and 6b, shown in (a) to (f) in the Fig. As shown in Figure 7, it is evident that the linear optical fiber 206 configured as described above produces a more uniform brightness. Accordingly, as shown in (g) to (i) in the Fig. Figure 7 shows the linear optical fiber 206 according to this embodiment compared with the linear optical fibers 6a and 6b, which are (a) to (f) in the Fig. 7 corresponds to a superior result. (Operating advantages)

[0085] Next, the operational advantages of the linear lighting device 201 according to this embodiment will be described.

[0086] As described above, in the linear illumination device 201 according to this embodiment, the laser light source 42 comprises a first laser light source arranged on a first side of the linear light guide 206, and a second laser light source arranged on a second side of the linear light guide 206. The phosphor body comprises a first phosphor body arranged between the first laser light source and the linear light guide 206, and a second phosphor body arranged between the second laser light source and the linear light guide 206. The first wavelength-converted light emitted by the first phosphor body enters the linear light guide 206 through the first entry surface 61a, which is a first end surface in the longitudinal direction.The second wavelength-modified light emitted by the second phosphor body enters the linear light guide 206 through the second entry surface 63a, which is a second end surface in the longitudinal direction.

[0087] This means that laser light sources 42 are arranged at both ends along the longitudinal direction of the linear light guide 206, and light enters the linear light guide 206 through both ends along its longitudinal direction. This enables the emission of a significant amount of light even in the central region of the linear light guide 206, far from the laser light sources 42, since the light is directed from both ends along its longitudinal direction to the central region of the linear light guide 206. This makes it easy to emit uniformly wavelength-converted light from the emission surface 262, which is characterized by reduced brightness variation.

[0088] In the linear illumination device 201 according to this embodiment, the light emission device is an uneven surface structure defined by depressions 64 or protrusions in or on the emission surface 262 of the linear light guide 206. The density of the depressions 64 or the protrusions in the uneven surface structure gradually increases with the distance from the first entry surface 61a to the central region of the linear light guide 206 and from the second entry surface 63a to the central region of the linear light guide 206.

[0089] As a result, the density of the depressions 64 or the protrusions in the uneven surface structure gradually increases with the distance from the first entry surface 61a to the central region of the linear optical fiber 206 and from the second entry surface 63a to the central region of the linear optical fiber 206. This makes it possible to emit a significant amount of light even in the central region of the linear optical fiber 206, which is located away from the laser light sources 42, since the light is guided longitudinally from both ends to the central region of the linear optical fiber 206. This makes it easy to emit uniformly wavelength-transformed light from the emission surface 262, which is characterized by reduced brightness inconsistency.

[0090] This embodiment also achieves further operational advantages that are achieved by embodiment 1. (Variation of embodiment 2)

[0091] The Fig. Figure 8A shows a cross-sectional view of a linear light guide 306 in a linear lighting device 201 according to a variation of embodiment 2.

[0092] In this variation, the recesses 164 or the protrusions differ from embodiment 1 in that their depth or height varies. Furthermore, unless otherwise specified, the linear lighting device 201 in this embodiment has the same configuration as in embodiment 2. Accordingly, corresponding elements have corresponding reference numerals in the drawings, and a repeated detailed description of these elements is omitted.

[0093] As it is in the Fig. As shown in Figure 8A, a plurality of depressions 164 are formed in the emission surface 362 of the linear optical fiber 306. The depth or height of the depressions 164, or the protrusions in the uneven surface structure, gradually increases with the distance from the first entry surface 61a to the central region of the linear optical fiber 306 and from the second entry surface 63a to the central region of the linear optical fiber 306. Each depression 164 has the same diameter.

[0094] With this configuration, in the linear illumination device 201 according to this variation, the light emission device is an uneven surface structure defined by a plurality of depressions 164 in or protrusions on the first emission surface 362 of the linear light guide 306. The depth or height of the depressions 164 or the protrusions in the uneven surface structure gradually increases with the distance from the first entry surface 61a to the central region of the linear light guide 306 and from the second entry surface 63a to the central region of the linear light guide 306. Fig. Figure 8B shows a cross-sectional view of the linear light guide 306 in the linear lighting device 201 according to a variation of embodiment 2. Fig. Figure 8B shows a linear optical fiber 306b comprising a plurality of protrusions 164b in the uneven surface structure.

[0095] As it is in the Fig. As shown in Figure 8A, the depth or height of the depressions 164 or the protrusions gradually increases with the distance from the entrance surface 61. This makes it possible to emit a significant amount of light even in the central region of the linear optical fiber 306, which is located away from the laser light sources 42, since the light is guided longitudinally from both ends to the central region of the linear optical fiber 206. This makes it easy to emit uniformly wavelength-converted light from the emission surface 362, which is characterized by reduced brightness variation.

[0096] These variations also achieve further operational advantages, which are achieved by embodiment 2. (Further variations, etc.)

[0097] The present disclosure has been described above on the basis of embodiments 1 and 2 and variations of embodiments 1 and 2, but the present disclosure is not limited to embodiments 1 and 2 and variations of embodiments 1 and 2 described above.

[0098] For example, a reflective component that reflects light can be arranged on the first emission surface in the linear light guide according to embodiments 1 and 2 and variations of embodiments 1 and 2. This reflective component can be made of metal or, for example, of an opaque white resin, such as polybutylene terephthalate.

[0099] The linear lighting device according to embodiments 1 and 2 and variations of embodiments 1 and 2 can be flexible. For example, the linear light guide, the housing, the reflective plate, and the translucent plate can be flexible.

[0100] Embodiments obtained by a person skilled in the art by carrying out various modifications with each of embodiments 1 and 2 and variations 1 and 2 of embodiments 1 and 2, as well as embodiments realized by any combination of structural components and functions in embodiments 1 and 2 and variations 1 and 2 that do not deviate from the essence of the present disclosure, are included in the present disclosure. [List of reference symbols] 1, 201 Linear lighting device (lighting device) 6, 6b, 206, 206b, 306, 306b Linear optical fiber 42 Laser light source 44 Fluorescent lamps (wavelength converters) 61 Entry surface (end surface in the longitudinal direction) 61a First entry surface (end surface in the longitudinal direction) 62 First emission surface (side surface) 63a Second entry surface (end surface in the longitudinal direction) 64, 164 Recess (light emission device, uneven surface structure) 64b, 164b Protrusion (light emission device, uneven surface structure) 262, 362 Emission surface (side surface or side surface)

Claims

[1] Lighting device (1, 201), comprising: a laser light source (42) that emits laser light; a wavelength converter that converts a wavelength of the laser light and emits wavelength-converted light; a first lens (46) which focuses the wavelength-converted light emitted by the wavelength converter (44); a second lens (47), which further focuses the wavelength-modified light from the first lens (46); and a linear optical fiber (6, 6b, 206, 206b, 306, 306b) which is elongated and guides the wavelength-modified light from the second lens (47) which is introduced longitudinally through an end face (61a, 63a), wherein the linear optical fiber (6, 6b, 206, 206b, 306, 306b) comprises a side surface (62, 262, 362) which emits the wavelength-modified light from the linear optical fiber (6, 6b, 206, 206b, 306, 306b) which is guided through the linear optical fiber (6, 6b, 206, 206b, 306, 306b), and the proportion of wavelength-modified light emitted through the side surface (62, 262, 362) gradually increases with increasing optical path length in the linear optical fiber (6, 6b, 206, 206b, 306, 306b). [2] Lighting device (1) according to claim 1, wherein the side surface (62) comprises an uneven surface structure defined by depressions (64) in or protrusions (64b) on the side surface (62) of the linear light guide (6), and the density of the depressions (64) or protrusions (64b) of the uneven surface structure gradually increases with the distance from the end surface (61) in the longitudinal direction. [3] Lighting device (1) according to claim 1 or 2, wherein the side surface (62) comprises an uneven surface structure defined by depressions (164) in or protrusions (164b) on the side surface (62) of the linear light guide (6b), and the depth or height of the depressions (164) or protrusions (164b) of the uneven surface structure gradually increases with the distance from the end face (61) in the longitudinal direction. [4] Lighting device (201) according to claim 1, wherein the laser light source (42) comprises a first laser light source arranged on a first side of the linear light guide (206, 206b, 306, 306b) and a second laser light source arranged on a second side of the linear light guide (206, 206b, 306, 306b), the wavelength converter (44) comprises a first wavelength converter arranged between the first laser light source and the linear optical fiber (206, 206b, 306, 306b), and a second wavelength converter arranged between the second laser light source and the linear optical fiber (206, 206b, 306, 306b), the first wavelength-converted light emitted by the first wavelength converter enters the linear optical fiber (206, 206b, 306, 306b) in the longitudinal direction through a first end surface (61a), and the second wavelength-converted light emitted by the second wavelength converter enters the linear optical fiber (206, 206b, 306, 306b) through a second end surface (63a) in the longitudinal direction. [5] Lighting device (201) according to claim 4, wherein the side surface (262) comprises an uneven surface structure defined by depressions (64) in or protrusions (64b) on the side surface (262) of the linear light guide (206, 206b), and the density of the depressions (64) or protrusions (64b) in the uneven surface structure gradually increases from the first end face (61a) in the longitudinal direction to a central area of ​​the linear optical fiber (206, 206b) and from the second end face (63a) in the longitudinal direction to the central area. [6] Lighting device (201) according to claim 4 or 5, wherein the side surface (362) comprises an uneven surface structure defined by depressions (164) in or protrusions (164b) on the side surface (362) of the linear light guide (306, 306b), and the depth or height of the depressions (164) or protrusions (164b) in the uneven surface structure gradually increases from the first end face (61a) in the longitudinal direction to a central area of ​​the linear optical fiber (306, 306b) and from the second end face (63a) in the longitudinal direction to the central area. [7] Lighting device (1, 201) according to one of claims 1 to 6, wherein the side surface (62, 262, 362) comprises an uneven surface structure defined by depressions (64, 164) in or protrusions (64b, 164b) on the side surface (62, 262, 362) of the linear light guide (6, 6b, 206, 206b, 306, 306b), and the depressions (64, 164) or the protrusions (64b, 164b) in the uneven surface structure are prisms, each of which has any of the following shapes: a circular cone, a hemisphere, a truncated circular cone, a truncated pyramid and a pyramid. [8] Lighting device (1, 201) according to one of claims 1 to 7, wherein the side surface (62, 262, 362) comprises an uneven surface structure defined by depressions (64, 164) in or protrusions (64b, 164b) on the side surface (62, 262, 362) of the linear light guide (6, 6b, 206, 206b, 306, 306b), and in a top view of the depressions (64, 164) or the protrusions (64b, 164b) in the uneven surface structure each of the depressions (64, 164) or the protrusions (64b, 164b) has approximately the same inner diameter or outer diameter. [9] Lighting device (1, 201) according to any one of claims 1 to 8, further comprising: a reflector (7) that reflects the wavelength-modified light emitted through the linear optical fiber (6, 6b, 206, 206b, 306, 306b); a translucent plate (8) which allows the wavelength-modified light to pass through; and a housing (3) that accommodates the laser light source (42), the wavelength converter (44), the linear optical fiber (6, 6b, 206, 206b, 306, 306b) and the reflector (7) and includes the light-transmitting plate (8) in an opening (3a) through which the wavelength-converted light passes, wherein the reflector (7) is aligned in the housing (3) such that it reflects the wavelength-modified light in the direction of the opening (3a). [10] Lighting device (1, 201), comprising: a laser light source (42) that emits laser light; a wavelength converter (44) that converts a wavelength of the laser light and emits wavelength-converted light; a first lens (46) that focuses the wavelength-converted light emitted by the wavelength converter (44); a second lens (47), which further focuses the wavelength-modified light from the first lens (46); and a linear optical fiber (6, 6b, 206, 206b, 306, 306b) which is elongated and guides the wavelength-modified light from the second lens (47) which is introduced longitudinally through an end face (61a, 63a), wherein the linear optical fiber (6, 6b, 206, 206b, 306, 306b) comprises a light emission device which emits from a side face of the linear optical fiber (6, 6b, 206, 206b, 306, 306b) the wavelength-converted light which is guided through the linear optical fiber (6, 6b, 206, 206b, 306, 306b), and the proportion of wavelength-modified light emitted by the light emission device gradually increases with increasing optical path length in the linear optical fiber (6, 6b, 206, 206b, 306, 306b).

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