JPWO2017104047A1 - Lighting device and endoscope system - Google Patents

Abstract

  The distribution unit (77) of the illuminating device (60) is disposed at least in the intensity region (93), and at least in order to reduce the intensity of the primary light (63) in the intensity region (93), the primary light (63). A path changing member (79) that changes at least a part of the traveling direction, and primary light (63) whose traveling direction has been changed by the path changing member (79) is reflected toward the emission surface (71b), and The first reflecting member (81) reflects the secondary light (65) traveling in the direction opposite to the exit surface (71b) toward the exit surface (71b).

Description

  The present invention relates to an illumination device and an endoscope system having the illumination device.

  For example, in the illumination device disclosed in Patent Document 1, a part of excitation light, which is primary light guided by an optical fiber after being emitted from an excitation light source, is output to an output unit disposed at the tip of the optical fiber. The wavelength is converted to generate secondary light that is wavelength-converted light. The illumination device mixes the primary light and the secondary light and emits them as illumination light.

The excitation light source has a laser diode element that emits primary light having an emission peak wavelength in the vicinity of 405 nm. The laser diode element is a GaN-based semiconductor element. The optical fiber is a silica-based optical fiber. The output unit includes a wavelength conversion member that absorbs a part of the primary light, converts the wavelength, and emits secondary light in a predetermined wavelength range. The wavelength converting member has a fluorescent substance contained in the silicone resin, phosphor _{Ca 10 (PO 4) 6 C} l2: and _{Eu, Lu 3 Al 5 O 12} : and Ce, (Ca, _{Sr) 2} Si ₅ N ₈ : Eu is used. The fluorescent material is uniformly mixed in the silicone resin.

  The primary light emitted from the laser diode element passes through a lens arranged in the excitation light source and is condensed by the lens on the emission part of the excitation light source. The emission part is optically connected to the optical fiber, and the primary light emitted from the emission part enters the optical fiber and is guided by the optical fiber. And primary light is radiate | emitted toward the output part from the output end surface of an optical fiber. The wavelength conversion member of the output unit absorbs a part of the primary light and generates secondary light. And illumination light is emitted.

  The illumination light is emitted in white, the average color rendering index (Ra) of the illumination light is 80 or more, and the special color rendering index (R9) indicating a red color chart is particularly high. As a result, a lighting device having high color rendering properties is provided.

JP 2005-205195 A

  Here, the central axis of the primary light emitted from the emission end face of the optical fiber toward the output unit is referred to as an optical axis. The optical axis periphery includes the optical axis. The wavelength conversion member is disposed at least on the optical axis.

  Since the directivity of the primary light that is the excitation light is strong, the primary light can be incident on the optical fiber with high efficiency by the lens and the emitting portion. However, since the directivity is strong, the spread angle of the primary light emitted from the emission end face of the optical fiber is small. Therefore, when the primary light irradiates the wavelength conversion member, even if a transparent member is disposed between the output end face of the optical fiber and the wavelength conversion member in the optical axis direction, the irradiation region of the primary light in the wavelength conversion member is narrow. This narrow irradiation region has a peripheral region that is a region around the optical axis, and an outer edge region that is disposed on the inner side of the irradiation region and on the outer side of the peripheral region and is an outer edge side region of the irradiation region. The intensity of the primary light is further increased in the peripheral region as compared to the outer edge region. Further, when the wavelength conversion member generates secondary light, heat is generated in the wavelength conversion member by generation, and most of the heat is generated from the peripheral region. In the peripheral region of the wavelength conversion member, deterioration is accelerated by the high intensity of primary light and heat. Further, the conversion efficiency for converting the primary light into the secondary light, in other words, the illumination light extraction efficiency decreases due to this deterioration, and the output of the illumination light decreases. Therefore, there is a demand for an illuminating device that can reduce the intensity of primary light in the peripheral region, has high extraction efficiency of illumination light, and high output of illumination light.

  The present invention has been made in view of these circumstances, and an illumination device capable of reducing the intensity of primary light in the peripheral region of the optical axis, having high illumination light extraction efficiency, and high illumination light output, and the illumination It is an object of the present invention to provide an endoscope system having the apparatus.

  In one aspect of the illumination device of the present invention, a part of the optical characteristics of the primary light emitted from the emission part of the light source unit toward the illumination unit is converted by the light conversion member of the illumination unit to convert the secondary light. The generated illumination light is emitted from the exit surface of the illumination unit. When the central axis of the primary light emitted from the emission part is defined as an optical axis and the light conversion member is assumed to be directly irradiated with the primary light emitted from the emission part, the light conversion is performed. An irradiation region irradiated with the primary light in the member is defined as a first irradiation region, and a region in the first irradiation region where the intensity of the primary light is a predetermined value or more is defined as an intensity region. The lighting device is disposed in the lighting unit, reduces at least the intensity of the primary light in the intensity region, and reduces the intensity of the primary light corresponding to the reduced region other than the intensity region in the light conversion member. And a distribution unit that distributes the irradiation area to a second irradiation area wider than the first irradiation area. The distribution unit is disposed at least in the intensity region, and at least a course changing member that changes a traveling direction of the primary light in order to reduce the intensity of the primary light in the intensity region; The primary light whose traveling direction has been changed by the path changing member is reflected toward the exit surface, and the secondary light traveling in the direction opposite to the exit surface is reflected toward the exit surface. 1 reflective member.

  One aspect of the endoscope system of the present invention includes an endoscope, a light source unit having an emission part that emits primary light, and the above-described illumination device disposed in the endoscope.

  ADVANTAGE OF THE INVENTION According to this invention, the intensity | strength of the primary light in the peripheral area | region of an optical axis can be reduced, the illuminating device with high extraction efficiency of illumination light and high output of illumination light, and an endoscope system having this illuminating device are provided. it can.

FIG. 1 is a schematic diagram of an endoscope system according to the first embodiment of the present invention. FIG. 2A is a diagram illustrating a first configuration of the light source unit and the illumination device. Drawing 2B is a figure showing the 1st type of the 2nd composition of a light source unit and an illuminating device. FIG. 2C is a diagram illustrating a second type of the second configuration of the light source unit and the illumination device. FIG. 3A is a diagram illustrating an example of the configuration of the illumination device in the first configuration illustrated in FIG. 2A. FIG. 3B is a diagram illustrating a relationship between various angles in the illumination unit of the illumination device illustrated in FIG. 3A. FIG. 3C is a diagram illustrating an example of the configuration of the illumination device in the first configuration illustrated in FIG. 2A. FIG. 3D is a diagram illustrating an example of the configuration of the illumination device in the first configuration illustrated in FIG. 2A. FIG. 4A shows an example of a configuration of an illumination device in which a course changing member is not arranged, and a diagram showing a positional relationship among a first irradiation region, an intensity region, and a first outer edge region in a light conversion member arranged in this configuration. It is. 4B is a diagram illustrating a primary light intensity distribution which is a relationship between the primary light intensity and the primary light spreading angle in the irradiation region of the light conversion member illustrated in FIG. 4A. 4C is a diagram showing the intensity distribution of the primary light shown in FIG. 4A and the intensity distribution of the primary light in the configuration shown in FIG. 3A. FIG. 5A is a diagram illustrating an example of the configuration of the illumination device according to the second embodiment. FIG. 5B is a diagram illustrating a first modification of the configuration of the illumination device illustrated in FIG. 5A. FIG. 5C is a diagram illustrating a second modification of the configuration of the lighting device illustrated in FIG. 5A. FIG. 6 is a diagram illustrating an example of the configuration of the illumination device according to the third embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in some drawings, illustration of some of the members is omitted for clarity of illustration. For clarity of illustration, for example, only a part of each of the primary light 63, the secondary light 65, and the illumination light 67 is illustrated.

[First Embodiment]
[Constitution]
A first embodiment will be described with reference to the drawings.
[Endoscope system 10]
An endoscope system 10 as shown in FIG. 1 is provided, for example, in an examination room or an operating room. The endoscope system 10 is an image (not shown) that performs image processing on an image of the endoscope 20 that is imaged by an imaging unit (not shown) of the endoscope 20 and an endoscope 20 that images the inside of the channel such as a patient's lumen. And a control device 30 having a processing unit. The endoscope system 10 includes a display device 40 that is connected to the control device 30 and displays an image subjected to image processing by the image processing unit.

  In the present embodiment, the medical flexible endoscope 20 will be described as an example of an insertion device to be inserted into the insertion target body, but the present invention is not limited to this. The insertion device is, for example, a medical rigid endoscope, an industrial flexible endoscope, an industrial rigid endoscope, a catheter, a treatment tool, or the like, and an insertion unit 21 that is inserted into an inserted body. As long as it has. The insertion portion 21 of this embodiment may be soft or hard. The object to be inserted is not limited to a person, but may be an animal or another structure.

  As shown in FIG. 1, the endoscope 20 includes a hollow and elongated insertion portion 21 that is inserted into a duct portion, and an operation portion 23 that is connected to a proximal end portion of the insertion portion 21 and operates the endoscope 20. Have The endoscope 20 includes a universal cord 25 that extends from the side surface of the operation unit 23. The universal cord 25 has a connection portion 25 a that can be attached to and detached from the control device 30.

[Configuration of Light Source Unit 50 and Lighting Device 60]
As shown in FIGS. 2A, 2B, and 2C, the endoscope system 10 includes a light source unit 50 and an illumination device that is disposed in the endoscope 20 and generates illumination light 67 emitted from the endoscope 20. 60. The light source unit 50 may be included in the lighting device 60. The illumination light 67 is emitted for imaging.

  In the first configuration of the light source unit 50 and the illumination device 60 shown in FIG. 2A and the second configuration of the light source unit 50 and the illumination device 60 shown in FIGS. 2B and 2C, the configuration of the illumination device 60 is the same. However, the configuration of the light source unit 50 is different.

  In the first configuration and the second configuration, the illumination device 60 includes an illumination unit 70 that emits illumination light 67 based on the primary light 63 emitted from the light source unit 50. Specifically, the illuminating device 60 converts a part of the optical characteristics of the primary light 63 emitted from the later-described emission unit of the light source unit 50 toward the illumination unit 70 by the light conversion member 73 of the illumination unit 70. Thus, the secondary light 65 is generated. For example, the illumination device 60 emits illumination light 67 in which the primary light 63 and the secondary light 65 are mixed from the emission surface 71 b of the illumination unit 70.

In the first configuration shown in FIG. 2A, the light source unit 50 includes a light source 51, a condensing unit 53, and a light guide member 55, and the illumination unit 70 is an output unit 59 of the light guide member 55 that is an output unit of the light source unit 50. To be optically connected.
In the second configuration shown in FIG. 2B and FIG. 2C, the light source unit 50 includes a light source 51, and the illumination unit 70 is optically connected to the light source 51 that is an emission part of the light source unit 50.

  In the first configuration, for example, the light source 51 and the light collecting unit 53 are built in the control device 30 or the operation unit 23, the light guide member 55 is built in the endoscope 20, and the illumination unit 70 is the tip of the insertion unit 21. Built in. In the second configuration, the light source unit 50 and the illumination unit 70 are built in the distal end portion of the insertion portion 21.

  In the first configuration and the second configuration, the central axis of the primary light 63 emitted from the emission part of the light source unit 50 toward the illumination unit 70 is defined as an optical axis 61. Specifically, in the first configuration, the central axis of the primary light 63 emitted from the emission part 59 of the light guide member 55 toward the illumination unit 70 is defined as the optical axis 61. In the second configuration, the central axis of the primary light 63 emitted from the light source 51 toward the illumination unit 70 is defined as the optical axis 61.

  In the first configuration shown in FIG. 2A, the primary light 63 emitted from the light source 51 is guided to the illumination unit 70 by the light guide member 55 and irradiates the illumination unit 70.

  In the second configuration shown in FIGS. 2B and 2C, the primary light 63 emitted from the light source 51 directly illuminates the illumination unit 70. In the second configuration, the first type (see FIG. 2B) that emits the primary light 63 having a wide beam divergence angle desired by the light source 51 such as a lamp or a light emitter Aode, and the light source 51 such as a laser diode is desired. And a second type (see FIG. 2C) that emits primary light 63 having a narrow beam divergence angle.

  In the following, the present embodiment will be described based on the first configuration.

[Light source unit 50]
The light source unit 50 shown in FIG. 2A includes one or more light sources 51 that emit primary light 63 in a specific wavelength range, and a light collecting unit that condenses the primary light 63 emitted from the light source 51 on the light guide member 55. 53 and a light guide member 55 that guides the primary light 63.

  The light source 51 is, for example, one of a laser diode, a light emitting diode, a surface emitting semiconductor laser, and a lamp. In the present embodiment, when the light source 51 is optically coupled to the light guide member 55 via the light condensing unit 53, the optical coupling efficiency is high, the reliability as the light source 51 is high, and the laser diode is the light source 51. As preferred. A plurality of light sources 51 that emit primary light 63 in different wavelength ranges may be disposed, and the primary light 63 may be combined by a combining unit such as a fiber coupler and incident on the light guide member 55.

  The condensing part 53 is an optical member such as a lens, for example.

  The light guide member 55 has flexibility and flexibility, for example, and is bent by receiving an external force. The light guide member 55 is elongate and has a cylindrical shape, for example. The light guide member 55 includes an incident portion 57 into which the primary light 63 collected by the condensing portion 53 is incident, and an emitting portion 59 that emits the primary light 63 toward the illumination unit 70. The incident portion 57 is disposed at the focal position of the light collecting portion 53. The planar incident portion 57 is disposed at one end portion of the light guide member 55, and the planar exit portion 59 is disposed at the other end portion of the light guide member 55. The light guide member 55 guides the primary light 63 from the incident part 57 toward the emission part 59.

  The light guide member 55 is, for example, one of a light guide, a light pipe, a light guide path, a bundle fiber, and an optical fiber. In the present embodiment, the light guide member 55 is a single-wire optical fiber. As shown in FIG. 3A, the optical fiber includes a core 55a and a clad 55b that covers the outer periphery of the core 55a. An incident portion 57 is disposed at one end of the core 55a, and an emitting portion 59 is disposed at the other end of the core 55a. As this optical fiber, for example, a multimode single-wire optical fiber having a numerical aperture Fna of approximately 0.22 and a core 55a diameter of 50 μm is used. The primary light 63 is emitted from the emission part 59 at an angle formed with the optical axis 61 according to the numerical aperture Fna.

[Lighting unit 70]
As shown in FIG. 3A, the central axis of the illumination unit 70 is preferably located on the optical axis 61.
The illumination unit 70 includes a frustoconical transparent member 71, a columnar light conversion member 73, and a distribution unit 77. The distribution unit 77 includes a course changing member 79 and a first reflecting member 81. The light conversion member 73 and the course changing member 79 are embedded in the transparent member 71. The central axis of the transparent member 71, the central axis of the light conversion member 73, and the central axis of the course changing member 79 are preferably disposed on the optical axis 61. The 1st reflection member 81 is arrange | positioned at the taper-shaped outer peripheral surface of the transparent member 71 which is a surface except the entrance surface 71a and the output surface 71b mentioned later.

[Transparent member 71]
As shown in FIG. 3A, the transparent member 71 has an incident surface 71 a that is optically connected to the emitting portion 59 and the primary light 63 is incident on the transparent member 71, and an emitting surface 71 b that emits the illumination light 67. . The diameter of the entrance surface 71a is smaller than the diameter of the exit surface 71b. The incident surface 71 a is a planar end surface of the transparent member 71, and the emission surface 71 b is a planar other end surface of the transparent member 71. The outer diameter of the incident surface 71 a is substantially the same as the outer diameter of the light guide member 55. The outer diameter of the incident surface 71a may be larger than the outer diameter of the light guide member 55. In this case, the first reflecting member 81 is disposed on the exposed portion of the incident surface 71a exposed to the light guide member 55. It is preferable.

  The transparent member 71 is a member that transmits the primary light 63 and the secondary light 65 with almost no absorption and attenuation. The transparent member 71 is an optically transparent member having a high transmittance with respect to the primary light 63 and the secondary light 65. Such a member is, for example, silicone resin, glass, or quartz glass.

  The transparent member 71 releases heat when the light conversion member 73 generates heat as the secondary light 65 is generated. The transparent member 71 is preferably a member having high thermal conductivity in order to efficiently release heat. Such a member is, for example, glass or glass-based resin. In order to efficiently release heat to the outside when heat is generated, the holding portion 85 that holds the other end portion of the light guide member 55 and the lighting unit 70 preferably has high thermal conductivity.

The transparent member 71 may be disposed between the emitting portion 59 and the light conversion member 73 in the direction of the optical axis 61.
[Light conversion member 73]
As shown in FIG. 3A, the light conversion member 73 embedded in the transparent member 71 is disposed between the emission portion 59 (incident surface 71a) and the emission surface 71b in the direction of the optical axis 61, and the incident surface 71a and the emission surface. 71b away from each other. The light conversion member 73 has, for example, a cylindrical shape. The light conversion member 73 has an incident surface 73a that is disposed on a plane that faces the emitting portion 59 and that receives at least the primary light 63, and a back surface 73b that is disposed on the back side of the incident surface 73a. Secondary light 65 is also incident on the incident surface 73a as shown by the broken line in FIG. 3A. In the direction of the optical axis 61, the incident surface 73a is separated from the incident surface 71a, and the back surface 73b is separated from the exit surface 71b. With such a positional relationship, the light conversion member 73 is reliably embedded in the transparent member 71. The peripheral surface of the light conversion member 73 including the incident surface 73a and the back surface 73b is a flat surface.

  Here, an angle formed between the first reflecting member 81 and the direction of the optical axis 61 is defined as an angle φ3 (see FIG. 3B). If a deviation occurs between the light quantity of the primary light 63 and the light quantity of the secondary light 65 reflected by the first reflecting member 81 at the angle φ3, the illumination light 67 will be uneven in color. For this reason, it is preferable that at least the edge 73 c of the light conversion member 73 is in contact with the first reflecting member 81. Thereby, uneven color is suppressed. Note that the edge portion 73 c indicates the edge portion 73 c of the incident surface 73 a of the light conversion member 73.

The light conversion member 73 converts the optical characteristics of the primary light 63 by being irradiated with the primary light 63, and generates and emits the secondary light 65. The optical property conversion is, for example, any one of wavelength conversion, light distribution (spreading angle) conversion, color unevenness reduction, and good color mixing of the primary light 63 and the secondary light 65. Indicates.
Below, an example of the light conversion member 73 is demonstrated easily, without using a figure.

The light conversion member 73 has, for example, one or more wavelength conversion members.
The wavelength converting member absorbs a part of the primary light 63 by being irradiated with the primary light 63, converts the wavelength of the absorbed primary light 63, and converts the secondary light 65 different from the primary light 63. Is generated. The wavelength conversion member includes a fluorescent material that converts the primary light 63 into light having a desired wavelength. In this case, the primary light 63 and the secondary light 65 are mixed and emitted as illumination light 67. .

  In addition, as a structure of a wavelength conversion member, a wavelength conversion member may have a some wavelength conversion substance mixed with respect to each other. In this case, each of the wavelength conversion materials generates secondary light 65 having a different wavelength. Or as a structure of a wavelength conversion member, you may laminate | stack one wavelength conversion member on the other wavelength conversion member. In this case, each of the wavelength conversion members generates secondary light 65 having different wavelengths. Then, the secondary lights 65 having different wavelengths are mixed and emitted as illumination light 67.

  In the present embodiment, the light conversion member 73 is a wavelength conversion member, and the illumination light 67 is described as a mixed color of the primary light 63 and the secondary light 65. In order to generate the illumination light 67 and reduce the color unevenness, the light conversion member 73 is preferably arranged perpendicular to the optical axis 61.

  The light conversion member 73 may include a diffusion member that diffuses the primary light 63 to generate the secondary light 65, for example. The diffusion member includes a transparent member and a diffusion material (not shown) called a filler added to the transparent member. The diffusing member widens the spread angle of the primary light 63 with respect to the optical axis 61, thereby generating the secondary light 65 having a wide spread angle. When the primary light 63 is laser light, the diffusing material repeatedly reflects or scatters the primary light 63. For this reason, a diffusing member reduces the coherence characteristic of laser light. In the diffusing member, in order to increase the extraction efficiency of the illumination light 67, it is important to minimize loss due to scattering. For this reason, for example, alumina is preferable as the diffusion material.

  When laser beams having a plurality of different wavelengths are combined, the diffusing member is irradiated to reduce coherence. Further, the diffusing member reduces uneven color due to the emission position of the illumination light 67 and realizes good color mixing light.

[Distribution unit 77]
Here, as shown in FIG. 4A, it is assumed that the course changing member 79 is not disposed and the light conversion member 73 is directly irradiated with the primary light 63 emitted from the emission unit 59. An irradiation area irradiated with the primary light 63 in the light conversion member 73 at this time is defined as a first irradiation area 91, and an area where the intensity of the primary light 63 is equal to or higher than a predetermined value in the first irradiation area 91 is an intensity area. 93. The predetermined value is a first intensity IS described later shown in FIGS. 4B and 4C. The intensity region 93 is a region around the optical axis 61. The first irradiation area 91 includes an intensity area 93 and a first outer edge area 95 that is an area on the outer edge side of the intensity area 93. The first outer edge region 95 is disposed inside the first irradiation region 91 and outside the intensity region 93.

  Here, the solid line in FIG. 4B and the dotted line in FIG. 4C indicate the relationship between the intensity of the primary light 63 and the spread angle of the primary light 63 in the irradiation region of the light conversion member 73 shown in FIG. 4A. Intensity distribution. The solid line in FIG. 4C is the intensity distribution in the configuration shown in FIG. 3A. As indicated by the solid line in FIG. 4B, the intensity of the primary light 63 is further increased in the intensity region 93 as compared with the first outer edge region 95. In the first irradiation region 91, an angle formed between the primary light 63 and the optical axis 61 is φ0. In the intensity region 93 existing inside the first irradiation region 91, an angle formed between the primary light 63 and the optical axis 61 is defined as φ1. The angle φ1 is smaller than the angle φ0.

  For example, also in FIG. 3A, the intensity region 93, the first outer edge region 95, and the first irradiation region 91 under the above assumption are illustrated.

  The first irradiation region 91 having the intensity region 93 and the first outer edge region 95 is a spot of the primary light 63 disposed on the incident surface 73 a of the light conversion member 73.

  The distribution unit 77 of this embodiment adjusts the intensity distribution indicated by the solid line in FIG. 4B and the dotted line in FIG. 4C to the intensity distribution indicated by the solid line in FIG. 4C, thereby adjusting the area of the irradiation region. In other words, the distribution unit 77 changes the intensity distribution and the area of the irradiation region. As shown in FIGS. 4B and 4C, the distribution unit 77 has an intensity that reduces the intensity of the primary light 63 in the intensity region 93, increases the extraction efficiency of the illumination light 67, and increases the output of the illumination light 67. The intensity of the primary light 63 in the area 93 is reduced, and the intensity of the reduced primary light 63 is an area other than the intensity area 93 in the light conversion member 73, for example, the first outer edge area 95 and the second outer edge area 99. And distribute to. The distribution unit 77 expands the irradiation area to the second irradiation area 97 wider than the first irradiation area 91 by distribution, and increases the intensity of the primary light 63 in the first outer edge area 95 and the second outer edge area 99. . For this reason, the distribution unit 77 includes a route changing member 79 and a first reflecting member 81. Note that the second irradiation region 97 is a spot of the primary light 63 disposed on the incident surface 73 a of the light conversion member 73. The second outer edge region 99 is disposed inside the second irradiation region 97 and outside the first outer edge region 95. The second outer edge region 99 is a region on the outer edge side of the second irradiation region 97.

[Course Change Member 79]
As shown in FIG. 3A, the course changing member 79 is disposed at least in the intensity region 93, and at least a part of the irradiated primary light 63 is reduced in order to reduce the intensity of the primary light 63 in at least the intensity region 93. Change the direction of travel. In other words, the course changing member 79 functions as a traveling direction changing member that changes the traveling direction, and functions as an adjusting member that adjusts the traveling direction. The course changing member 79 functions as an optical path changing member that changes the optical path of the primary light 63 when the course changing member 79 is not disposed. For example, the path changing member 79 reflects at least a part of the primary light 63 toward the first reflecting member 81 in order to change the propagation direction of the primary light 63 toward the first reflecting member 81. The course changing member 79 may be disposed at least in the strength region 93, for example, may be disposed so as to protrude to the first outer edge region 95, or may be disposed in the entire first irradiation region 91 as illustrated in FIG. 3A. Alternatively, it may be arranged so as to protrude further outward from the first irradiation region 91.

  As shown in FIGS. 3A, 3C, and 3D, the course changing member 79 includes, for example, a conical or hemispherical optical member 79a. The surface of the optical member 79a faces the emission part 59 side. For example, the maximum diameter of the optical member 79a may be the same as or larger than the diameter of the intensity region 93, and may be the same as or larger than the diameter of the first irradiation region 91, for example. The conical optical member 79a is preferably, for example, a right cone. In this case, the central axis of the optical member 79a is disposed on the optical axis 61, and an angle φ2 is formed between the optical axis 61 and the generatrix of the conical optical member 79a as shown in FIG. 3B. The optical member 79a reflects the primary light 63 on the surface of the optical member 79a. The refractive index n1 of the transparent member 71 is larger than the refractive index n2 of the optical member 79a.

  In the present embodiment, the incident angle of the primary light 63 incident on the conical tip of the conical optical member 79a is larger than the critical angle. Therefore, as shown in FIG. 3A, the optical member 79a totally reflects the primary light 63 on the surface of the optical member 79a. And the primary light 63 which permeate | transmits the optical member 79a is suppressed. For example, when the transparent member 71 is glass (n = 1.44), the optical member 79 a is a transparent member having a refractive index smaller than that of the transparent member 71. The critical angle is determined by, for example, the refractive index of the transparent member 71 and the refractive index of the optical member 79a.

  When the difference between the refractive index n1 and the refractive index n2 is small, total reflection is not performed. In this case, as shown in FIG. 3B, a part of the primary light 63 is reflected toward the first reflecting member 81 by the optical member 79a. Further, in the state where the spread angle between the remaining part of the primary light 63 and the optical axis 61 is widened so that the remaining part of the primary light 63 is separated from the periphery of the optical axis 61, The remaining part passes through the optical member 79 a and travels toward the light conversion member 73. That is, the optical member 79a separates the primary light 63 into reflected light and refracted transmitted light. The remaining part of the primary light 63 is refracted in the direction away from the optical axis 61 by the optical member 79a and passes through the optical member 79a.

  When total reflection does not occur, as shown in FIG. 3C, the path changing member 79 is disposed on the surface of the conical optical member 79 a, for example, inclined with respect to the optical axis 61, and the primary light 63. May be included in the second reflecting member 79 b that reflects the first reflecting member 81 toward the first reflecting member 81. The second reflecting member 79b is disposed at least in a region where total reflection does not occur in the optical member 79a in the vicinity of the optical axis 61. This region is arranged coaxially with the intensity region 93 in the direction of the optical axis 61, for example. For example, the second reflecting member 79b is disposed around the optical axis 61 and at the conical tip of the optical member 79a. Thus, the second reflecting member 79 b reliably reflects the primary light 63 in the vicinity of the optical axis 61 toward the first reflecting member 81.

  The reflectance of the second reflecting member 79b is preferably 90% or more. The second reflecting member 79b is, for example, a dielectric multilayer film that reflects the primary light 63 with a high reflectance.

  When the incident angle of the primary light 63 is smaller than the critical angle, the second reflecting member 79b may be disposed at least from the optical axis 61 to a region where the incident angle becomes the critical angle.

  Although not shown for simplicity, the optical member 79a in a region where the second reflecting member 79b is irradiated with a part of the primary light 63 and the second reflecting member 79b is not disposed in a state where total reflection does not occur. Is assumed to be irradiated with the remaining part of the primary light 63. In this case, a part of the primary light 63 is reflected toward the first reflecting member 81 by the second reflecting member 79b. Further, in the state where the spread angle between the remaining part of the primary light 63 and the optical axis 61 is widened so that the remaining part of the primary light 63 is separated from the periphery of the optical axis 61, The remaining part passes through the optical member 79 a and travels toward the light conversion member 73. That is, the optical member 79a separates the primary light 63 into reflected light and refracted transmitted light. The remaining part of the primary light 63 is refracted in the direction away from the optical axis 61 by the optical member 79a and passes through the optical member 79a.

  As shown in FIG. 3D, the course changing member 79 includes, for example, a third reflecting member 79c disposed on the surface of the hemispherical optical member 79a, and a random reflecting portion 79d that is at least part of the surface of the third reflecting member 79c. You may have.

  For example, the third reflecting member 79c is disposed on the entire surface of the optical member 79a. The third reflecting member 79c faces the emitting part 59 side. The third reflecting member 79 c reflects the primary light 63 toward the first reflecting member 81. The reflectance of the third reflecting member 79c is preferably 90% or more. The third reflecting member 79c suppresses the attenuation of the primary light 63 by the third reflecting member 79c, has wavelength selectivity, and reflects the secondary light 65 low. For this reason, the third reflecting member 79c is a dielectric multilayer film having wavelength selectivity in which reflection is repeatedly performed by the third reflecting member 79c and the primary light 63 is not attenuated, rather than a metal film having a high reflectance. Is preferred.

  Although illustration is omitted for simplification, most of the primary light 63 that irradiates the third reflecting member 79c is reflected toward the first reflecting member 81 by the third reflecting member 79c. The remaining part of the primary light 63 passes through the third reflecting member 79c without being reflected by the third reflecting member 79c. The primary light 63 passes through the optical member 79a toward the focal direction of the optical member 79a and irradiates the light conversion member 73.

  As shown in FIG. 3D, the irregular reflection portion 79d is disposed at least around the optical axis 61, and is disposed coaxially with the intensity region 93 in the optical axis 61 direction. The surface of the third reflecting member 79c, which is the irregular reflection portion 79d, has an uneven shape, and the height, size, or period of the unevenness is irregular. The height of the unevenness is equal to or less than the wavelength of the primary light 63. The irregular reflection part 79d diffusely reflects the primary light 63 that irradiates the irregular reflection part 79d, and reflects the primary light 63 toward other than the emission part 59.

  Although illustration is omitted for simplification, it is assumed that a planar reflection member is disposed in the irregular reflection portion 79d. In this case, the primary light 63 enters the light guide member 55 from the emission part 59 by reflection and returns to the light source 51. For example, when 10% or more of the primary light 63 emitted from the emission part 59 returns, the amount of this return light cannot be ignored. In this case, the phase of the return light and the phase of the primary light 63 emitted from the light source 51 interfere with each other, the output of the light source 51 fluctuates, and the output of the illumination device 60 becomes unstable. For this reason, it is necessary to suppress return light.

  For this reason, in this embodiment, the irregular reflection part 79d suppresses the primary light 63 from entering the light guide member 55 and returning to the light source 51 by irregular reflection. For this reason, the fluctuation | variation of the output of the light source 51 is suppressed, and the output of the illuminating device 60 is stabilized.

[First reflective member 81]
As shown in FIG. 3A, the first reflecting member 81 reflects the primary light 63 whose traveling direction has been changed by the path changing member 79 toward the exit surface 71b and travels in the opposite direction to the exit surface 71b. The secondary light 65 is reflected toward the emission surface 71b. The first reflecting member 81 reflects the primary light 63 toward a region other than the intensity region 93, for example, for the second irradiation region 97. The first reflecting member 81 is disposed from the emitting portion 59 to the emitting surface 71b in the direction of the optical axis 61, and is disposed so as to surround the light conversion member 73 and the course changing member 79. The first reflecting member 81 extends in a tapered shape from the emitting portion 59 toward the emitting surface 71b.

  The first reflecting member 81 reflects the primary light 63 and the secondary light 65 toward the exit surface 71b in order to change the propagation direction of the primary light 63 and the secondary light 65 toward the exit surface 71b. . Moreover, since the 1st reflection member 81 has spread in the taper shape, it will have the function to control the light distribution characteristic of the primary light 63, the secondary light 65, and the illumination light 67. FIG. The angle φ3 in the first reflecting member 81 controls the light distribution characteristics.

  The first reflecting member 81 is, for example, a dielectric multilayer film or a metal film having a high reflectance with respect to the primary light 63 and the secondary light 65. The metal is, for example, Ag or Al.

  A scattering film that suppresses scattering loss may be disposed on the surface of the first reflecting member 81. Thereby, the spread of the reflection angle in the first reflection member 81 is increased, the intensity distribution of the primary light 63 in the light conversion member 73 is uniform, and the color unevenness in the emission surface 71b is reduced.

  3B depends on the angle of the outer peripheral surface of the transparent member 71 with respect to the optical axis 61. The angle φ3 shown in FIG.

[Action]
The primary light 63 emitted from the light source 51 is condensed on the incident portion 57 of the light guide member 55 by the light collecting portion 53 and guided to the emission portion 59 by the light guide member 55. As shown in FIG. 3A, the primary light 63 emitted from the emission part 59 enters the transparent member 71 from the incident surface 71 a and passes through the transparent member 71.

  Here, as shown in FIG. 3B, it is assumed that the primary light 63 is incident on the optical member 79a from the incident position P on the generatrix of the conical optical member 79a. The incident position P is not the apex of the optical member 79a located on the optical axis 61 but a part of the tapered outer peripheral surface of the optical member 79a.

Here we define:
Angle formed between the primary light 63 emitted from the emission part 59 and the optical axis 61: angle φ1
When the primary light 63 is incident on the optical member 79a with the angle φ1, the incident angle of the primary light 63 with respect to the normal at the incident position P of the optical member 79a: ψ1
When the primary light 63 is refracted by the optical member 79a and then passes through the optical member 79a, a refraction angle formed between the refracted primary light 63 and the optical axis 61: ψ2
The relationship between the incident angle ψ1 and the refractive angle ψ2 depends on the difference Δn between the refractive index n1 of the transparent member 71 and the refractive index n2 of the optical member 79a.

  If the total reflection condition is satisfied, the primary light 63 is totally reflected at the incident position P, and the primary light 63 is reflected toward the first reflecting member 81 as shown in FIG. 3A. The primary light 63 is reflected again by the first reflecting member 81, and the reflected primary light 63 irradiates a region other than the intensity region 93 and enters the light conversion member 73 from this region.

  If the condition of total reflection is not satisfied, as shown in FIG. 3B, a part of the primary light 63 is reflected toward the first reflecting member 81 by the optical member 79a at the incident position P. A part of the primary light 63 is reflected again by the first reflecting member 81, irradiates a region other than the intensity region 93, and enters the light conversion member 73 from this region. Further, in the state where the spread angle between the remaining part of the primary light 63 and the optical axis 61 is widened so that the remaining part of the primary light 63 is separated from the periphery of the optical axis 61, The remaining part passes through the optical member 79 a, travels toward the light conversion member 73, and enters the light conversion member 73.

  Whether the total reflection condition is satisfied or not satisfied, the course changing member 79 is arranged and the primary light 63 is reflected toward the first reflecting member 81. For this reason, for example, the first optical path length (not shown) of the primary light 63 is longer than the second optical path length (not shown) of the primary light 63. The first optical path length is a length by which the primary light 63 travels from the incident surface 71 a to the light conversion member 73 via the path changing member 79 and the first reflecting member 81. The second optical path length is a length in which the primary light 63 travels directly from the incident surface 71a to the light conversion member 73 in a state where the course changing member 79 is not disposed. Further, the course changing member 79 is disposed, and the primary light 63 enters the light conversion member 73 from a region other than the intensity region 93. Therefore, as shown in FIG. 4C, the intensity of the primary light 63 in the intensity region 93 is reduced, and the reduced intensity of the primary light 63 is distributed to areas other than the intensity area 93 in the light conversion member 73. In addition, due to the distribution, the irradiation region in the light conversion member 73 extends from the first irradiation region 91 to the second irradiation region 97, and the intensity of the primary light 63 in the region other than the intensity region 93 increases.

  As shown in FIG. 3A, a part of the primary light 63 incident on the light conversion member 73 is absorbed by the light conversion member 73 and converted into the secondary light 65. The remaining part of the primary light 63 is emitted from the light conversion member 73 toward the emission surface 71 b without being absorbed by the light conversion member 73. The primary light 63 emitted from the incident surface 73a is reflected toward the light conversion member 73 by the first reflecting member 81, and the above-described operation is repeated again.

  As shown in FIG. 3A, a part of the secondary light 65 is emitted from the light conversion member 73 toward the emission surface 71b. The remaining part of the secondary light 65 is emitted from the incident surface 73 a toward the first reflecting member 81, is reflected by the first reflecting member 81, and passes through the light conversion member 73. The secondary light 65 is mixed with the primary light 63 emitted from the light conversion member 73 without being absorbed by the light conversion member 73, and is emitted from the emission surface 71 b as illumination light 67.

Next, with reference to FIG. 4A, FIG. 4B, and FIG. 4C, the reduction | decrease of the intensity | strength of primary light and distribution of primary light are demonstrated.
FIG. 4A shows a state in which the route changing member 79 is not disposed and the light conversion member 73 is directly irradiated with the primary light 63 emitted from the emission unit 59. A transparent member 71 is disposed between the emitting portion 59 and the light conversion member 73 in the direction of the optical axis 61. The transparent member 71 ensures a longer length from the emitting portion 59 to the light converting member 73 than in a contact state where the transparent member 71 is not disposed and the emitting portion 59 is in contact with the light converting member 73.

  As indicated by the solid line in FIG. 4B, the intensity of the primary light 63 is further increased in the intensity region 93 as compared with the first outer edge region 95. When the light conversion member 73 generates the secondary light 65, heat is generated in the first irradiation region 91 due to the generation, and most of the heat is generated from the intensity region 93.

Therefore, the intensity region 93 is a heat deterioration acceleration region in which the deterioration of the light conversion member 73 may be accelerated due to the high intensity of the primary light 63 and the heat generated by the generation of the secondary light 65. . Hereinafter, the deterioration of the light conversion member 73 caused by the high intensity and heat of the primary light 63 is referred to as heat deterioration. As shown in FIG. 4B, the strength region 93 includes a heat deterioration region 93a that is a central region and a heat deterioration warning region 93b that is an outer region of the heat deterioration region 93a. The intensity of the primary light 63 in the intensity region 93 is from the peak intensity IP to a predetermined first intensity IS. The peak intensity IP is the highest intensity. The first intensity IS is an intensity that depends on the light conversion efficiency of the light conversion member 73 at a high temperature in consideration of conduction of generated heat. As an example of the actual setting of the first intensity IS, IS = IP × 1 / e ² . e is a natural logarithm. The first intensity IS is a predetermined value of the primary light in the intensity region 93 and indicates, for example, 1 / e ² with respect to the peak intensity IP that is the peak value of the intensity of the primary light.

  The intensity of the primary light 63 in the thermally deteriorated region 93a is from the peak intensity IP to a predetermined second intensity ID. The second intensity ID indicates between the peak intensity IP and the first intensity IS and is set as desired. The heat deterioration region 93a indicates a portion where the intensity of the primary light 63 is highest in the irradiation region and the acceleration of heat deterioration is the highest in the light conversion member 73.

  The intensity of the primary light 63 in the heat deterioration warning area 93b is from the second intensity ID to the first intensity IS. The heat deterioration warning area 93b is a portion where the intensity of the primary light 63 is lower than that of the heat deterioration area 93a and the acceleration of the heat deterioration is next to the heat deterioration area 93a, and the deterioration is watched.

  The first outer edge region 95 is a safety region outside the heat deterioration warning region 93b and inside the first irradiation region 91, and indicates a region that can be regarded as having no acceleration of heat deterioration. The intensity of the primary light 63 in the first outer edge area 95 is lower than that in the heat deterioration warning area 93b, and is less than the first intensity IS to 0. The intensity of the primary light 63 in the first outer edge region 95 is a safe intensity that can be regarded as no acceleration of thermal degradation.

  When thermal degradation occurs, the conversion efficiency for conversion to the illumination light 67, in other words, the extraction efficiency of the illumination light 67 decreases, and the output of the illumination light 67 decreases.

  For this reason, in this embodiment, as shown in FIG. 3A, the course changing member 79 is disposed at least in the strength region 93 (the heat deterioration region 93a and the heat deterioration warning region 93b), and the first reflecting member 81 is also disposed. The Therefore, as shown in FIG. 4C, the intensity of the primary light 63 in the intensity region 93 is reduced, and the reduced intensity of the primary light 63 is distributed to areas other than the intensity area 93 in the light conversion member 73. In addition, due to the distribution, the irradiation region in the light conversion member 73 extends from the first irradiation region 91 to the second irradiation region 97, and the intensity of the primary light 63 in the region other than the intensity region 93 increases. As a result, the intensity distribution is changed to a donut shape indicated by a solid line in FIG. 4C. In the intensity region 93, as described above, the intensity of the primary light 63 is reduced, so that a reduced region 99a is generated. The reduced region 99a is a region surrounded by a dotted line and a solid line in the intensity region 93 of FIG. 4C. 3B and 4C, the irradiation region extends from the first irradiation region 91 to the second irradiation region 97, the angle φ0 extends to the angle φ0 ′, and regions other than the intensity region 93 are also included in the first outer edge region 95. And the second outer edge region 99. As shown in FIG. 3B, the angle φ0 ′ is a straight line connecting the emitting portion 59 and the incident position on the incident surface 73a when the primary light 63 reflected by the first reflecting member 81 irradiates the incident surface 73a. , The maximum angle formed with the optical axis 61. When the irradiation region extends from the first irradiation region 91 to the second irradiation region 97, an increased region 99b is generated. The increase region 99b has a total intensity of the primary light 63 that is substantially the same as that of the decrease region 99a. The increase area 99b is an area surrounded by a dotted line and a solid line in an area other than the intensity area 93 in FIG. 4C. The total intensity of the primary light 63 in the first outer edge region 95 and the second outer edge region 99 also increases substantially equally by the reduced primary light 63.

  The heat generated in the light conversion member 73 is efficiently transmitted to the holding unit 85 via the transparent member 71 and the first reflecting member 81 by the donut-shaped intensity distribution (expansion of irradiation area). Therefore, heat generation in the intensity region 93 far from the holding portion 85 from the heat transfer flow is suppressed, and the temperature distribution of the light conversion member 73 can be made uniform. When the light conversion member 73 is a wavelength conversion member, the wavelength conversion member has temperature dependency with respect to the peak wavelength of the spectrum of the primary light 63. For this reason, if the distribution unit 77 is not arranged, color unevenness occurs in the color of the illumination light 67. However, the distribution unit 77 eliminates uneven color.

Next, with reference to FIG. 3B, the reflection at the course changing member 79 and the reflection at the first reflecting member 81 will be described.
Here we define:
Angle formed between the primary light 63 emitted from the emission part 59 and the optical axis 61: φ1
Maximum angle of angle φ1: φ0
With the central axis of the optical member 79a disposed on the optical axis 61, an angle formed between the bus bar of the conical optical member 79a and the optical axis 61: φ2
Angle formed between the first reflecting member 81 and the direction of the optical axis 61: φ3
When the primary light 63 is incident on the optical member 79a with the angle φ1, the incident angle of the primary light 63 with respect to the normal at the incident position P of the optical member 79a: ψ1
When the primary light 63 is refracted by the optical member 79a and then passes through the optical member 79a, a refraction angle formed between the refracted primary light 63 and the optical axis 61: ψ2
Refractive index of transparent member 71: n1
Refractive index of the optical member 79a: n2
Based on this definition, the propagation direction of the primary light 63 changed by the route changing member 79 is examined.
Here, it is assumed that the conditions of n2 <n1 and 0 ≦ φ1 ≦ φ0 <φ2 occur.

First, the following formula (1) is established by n1 and ψ1, and n2 and ψ2.
n1 × sin ψ1 = n2 × sin ψ2 (1)
Here, when the critical angle in total reflection is ψt, the following equation (2) is established.
sinψt = n2 / n1 (2)
When the incident angle ψ1 is larger than the critical angle ψt, as shown in FIG. 3A, the primary light 63 is not refracted by the optical member 79a and does not pass through the optical member 79a, and is totally reflected. For this reason, the following equation (3) is established by the relationship between the incident angle ψ1, the critical angle ψt, and the angles φ1 and φ2 at the incident position P, and the equation (4) is calculated from the equations (3) and (4). This is a condition for total reflection.
ψt <ψ1 = π / 2− (φ2−φ1) (3)
φ2 <π / 2 + φ1-ψt (4)
φ2 is fixed, φ1 is an increasing function, and ψ1 is an increasing function.

Further, the angle φ2 is formed between the bus and the incident surface 73a of the light conversion member 73 so that the primary light 63 traveling toward the bus travels to the first reflecting member 81 at the same reflection angle as the incident angle on the bus. It must be smaller than the angle. For this reason, the following formula (5) needs to be satisfied.
2ψ1 <π / 2 + φ2 (5)
Since the primary light 63 is reflected by the optical member 79a and travels to the first reflecting member 81 with the angle φ1, the equation (3) is substituted into ψ1 of the equation (5), and the following equation (6a ) Needs to be satisfied.

2 (π / 2− (φ2−φ1)) <π / 2 + φ2
π-2φ2 + 2φ1 <π / 2 + φ2
π / 2 + 2φ1 <3φ2
π / 6 + 2 / 3φ1 <φ2 Formula (6a)
Since the angle φ1 changes from 0 ° to the maximum angle φ0, the following equation (6b) needs to be satisfied based on the equation (6a).
30 + 2 / 3φ0 <φ2 Formula (6b)
Since the angle φ1 changes from 0 ° to the maximum angle φ0, the following equation (7) needs to be set in order to perform total reflection based on the equation (4).
φ2 <π / 2 + φ1-ψt ≦ π / 2 + φ0−ψt (7)
For example, when the refractive index n1 of the transparent member 71 is 1.6 and the refractive index n2 of the optical member 79a is 1.35, the critical angle ψt is 57.5 °.

  When Na of the optical fiber is 0.22, in the medium having the refractive index of 1.6 of the transparent member 71, the full width at half maximum, which is the angle of the beam that is halved with respect to the peak intensity, is 7.9. Assuming that the angle formed with the optical axis 61 that is 1/4 or less with respect to the center intensity is 11.9 °, which is three times the half value, that is, φ0 = 12.0. Set with °.

  Substituting φ0 = 12.0 ° into equation (6b), 38 ° <φ2 is calculated from the condition that the primary light 63 is incident on the first reflecting member 81 shown in equation (6b).

  If the critical angle ψt in the equation (4) is larger than the critical angle ψt on the optical axis 61, the incident angle ψ1 also increases as the angle φ1 increases. For this reason, in Formula (4), if (phi) 2 is set to 32.5 degrees used as (pi) / 2-psit, for example, total reflection will be implemented in the surface of the optical member 79a. However, in this case, the condition for the reflected light to enter the first reflecting member 81 is not satisfied. For this reason, the second reflecting member 79b is disposed around the optical axis 61, and the ratio of the amount of reflected light is higher than the ratio of the amount of transmitted light in the ratio of the amount of transmitted light and the amount of reflected light. Distribution is distributed.

  That is, if Expression (6b) is satisfied, the primary light 63 is separated into reflected light and refracted transmitted light around the optical axis 61.

  In the present embodiment, the irradiation area extends from the first irradiation area 91 to the second irradiation area 97. That is, the angle formed between the primary light 63 and the optical axis 61 extends from the angle φ0 to the angle φ0 ′. Therefore, the light conversion member 73 needs to receive the primary light 63 having a spread angle of at least the angle φ0 ′. Therefore, φ0 <φ3. For example, it is preferable to set φ3 = 20 °.

  The primary light 63 having a high intensity in the intensity region 93 needs to be reliably reflected toward the first reflecting member 81. For this reason, as shown in FIG. 3C, the second reflecting member 79b is preferably disposed at least at the tip of the cone. The second reflecting member 79b reliably reflects most of the incident primary light 63 toward the second reflecting member 79b. As a result, the intensity of the primary light 63 in the intensity region 93 is reduced. The first reflecting member 81 reflects the primary light 63 toward the light conversion member 73. The reduced intensity of the primary light 63 is distributed to areas other than the intensity area 93 in the light conversion member 73. In addition, due to the distribution, the irradiation region in the light conversion member 73 extends from the first irradiation region 91 to the second irradiation region 97, and the intensity of the primary light 63 in the region other than the intensity region 93 increases.

  Consider that the primary light 63 is reflected at the reflection point Q of the first reflecting member 81.

  An incident angle that is a normal line at the reflection point Q is defined as ψ3. Here, the following formula (8) is established.

ψ3 = 2ψ1 + (φ3-φ1) −π / 2 Formula (8)
Substituting equation (3) into ψ1 in equation (8), the following equation (9) holds: ψ3 = 2 (π / 2− (φ2−φ1)) + (φ3−φ1) −π / 2
ψ3 = π-2φ2 + 2φ1 + φ3-φ1-π / 2
ψ3 = π / 2 − [(φ2−φ3) + (φ2−φ1)] (9)
In Expression (9), in order for the primary light 63 reflected by the first reflecting member 81 to be incident on the light conversion member 73 with respect to the angle φ1, ψ3 <π / 2 and (φ2−φ3 ) + (Φ2−φ1)> 0 needs to be satisfied.

  That is, φ3 <φ2 and φ1 ≦ φ0 <φ2 need to be satisfied.

Since φ1 <φ3, satisfying the following formula (10) is a condition for the primary light 63 reflected by the first reflecting member 81 to enter the light converting member 73.
φ1 <φ3 <φ2 Formula (10)
When the illumination device 60 is actually used, the maximum diameter of the emission surface 71b is defined according to the arrangement position of the illumination device 60. Therefore, the angle φ3 and the length from the entrance surface 71a to the exit surface 71b are limited by the maximum diameter.

[effect]
In the present embodiment, the course changing member 79 of the distribution unit 77 is disposed in the intensity region 93 and reflects the primary light 63 around the optical axis 61 toward the first reflecting member 81. For this reason, the intensity of the primary light 63 in the intensity region 93 can be reduced. Further, the first reflecting member 81 of the distribution unit 77 reflects the primary light 63 reflected by the route changing member 79 toward an area other than the intensity area 93 on the incident surface 73 a of the light converting member 73. For this reason, the irradiation region extends from the first irradiation region 91 to the second irradiation region 97, and the intensity of the primary light 63 in the region other than the intensity region 93 increases. Therefore, the extraction efficiency of the illumination light 67 can be increased, and the output of the illumination light 67 can be increased.

  In the present embodiment, since the intensity of the primary light 63 in the intensity region 93 is reduced, thermal deterioration of the light conversion member 73 can be suppressed. Further, since the irradiation area extends from the first irradiation area 91 to the second irradiation area 97, the distribution of heat generated by the generation of the secondary light 65 can be made substantially uniform.

  The first reflecting member 81 is disposed so as to surround the light conversion member 73 and the course changing member 79. For this reason, the first reflecting member 81 can reflect the primary light 63 and the secondary light 65 toward the region other than the intensity region 93 without leaking. The first reflecting member 81 extends in a tapered shape. For this reason, the first reflecting member 81 can reliably reflect the primary light 63 and the secondary light 65 toward an area other than the intensity area 93. The illumination light 67 can have a predetermined spread angle.

  The refractive index of the transparent member 71 is larger than the refractive index of the optical member 79a. For this reason, the primary light 63 can be reflected toward the first reflecting member 81 with a simple configuration.

  When total reflection is not performed, in a state where the spreading angle between the remaining part of the primary light 63 and the optical axis 61 is widened so that the remaining part of the primary light 63 is separated from the periphery of the optical axis 61, The remaining part of the primary light 63 passes through the optical member 79 a and travels toward the light conversion member 73. At this time, since the primary light 63 travels to a region other than the intensity region 93, the intensity of the primary light 63 in the intensity region 93 can be reduced.

  The second reflecting member 79b can reliably reflect the primary light 63 toward the first reflecting member 81 even if total reflection is not performed.

  The irregular reflection part 79 d can diffusely reflect the primary light 63 toward the first reflecting member 81 and can prevent the primary light 63 from returning to the light source 51.

  In FIG. 2C, the course changing member 79 has a columnar shape, for example, a cylindrical shape. In this case, the course changing member 79 may diffuse the primary light.

[Second Embodiment]
The second embodiment will be described with reference to FIG. 5A. In the present embodiment, only the parts different from the first embodiment will be described.

  The course changing member 79 of this embodiment diffuses at least a part of the primary light 63 toward the first reflecting member 81. For this reason, the course changing member 79 is disposed between the columnar diffusing member 79e that diffuses a part of the primary light 63, and the diffusing member 79e and the incident surface 73a of the light converting member 73 in the optical axis 61 direction. A fourth reflecting member 79f that reflects the remaining part of the primary light 63 toward the first reflecting member 81;

  The diffusion member 79e has, for example, a cylindrical shape. The diffusing member 79e includes a transparent member and a diffusing substance called a filler added to the transparent member. The diffusing member 79e widens the spreading angle of the primary light 63 with respect to the optical axis 61. When the primary light 63 is a laser, the diffusing material repeatedly reflects or scatters the primary light 63. For this reason, the diffusing member 79e reduces the coherence characteristic of laser light. In the diffusing member 79e, in order to increase the extraction efficiency of the illumination light 67, it is important to minimize loss due to scattering. For this reason, for example, alumina is preferable as the diffusion material.

  The concentration distribution of the diffusing substance in the transparent member of the diffusing member 79e corresponds to the angle φ1 and the intensity of the primary light 63. As the angle φ1 increases, the concentration decreases in inverse proportion. For example, the angle φ1 and the density N may be calculated so that the ratio I / N between the intensity I and the density N of the primary light 63 is constant. In order to suppress diffusion loss, it is preferable that the concentration of the diffusing substance is higher as it is closer to the optical axis 61 and lower as it is farther from the optical axis 61.

  In the direction of the optical axis 61, the diffusing member 79e is stacked on the fourth reflecting member 79f, and the fourth reflecting member 79f is stacked on the incident surface 73a of the light converting member 73. The fourth reflecting member 79f is disposed at least around the optical axis 61. The fourth reflecting member 79 f has a high reflectance with respect to the wavelength of the primary light 63. The fourth reflecting member 79f has wavelength selectivity. The fourth reflecting member 79f is, for example, a dielectric multilayer film.

  As the fourth reflecting member 79f and the transparent member 71, a member having high thermal conductivity is preferable in order to efficiently release heat to the light source 51.

[Action]
The primary light 63 emitted from the emission part 59 is transmitted through the transparent member 71 and incident on the diffusion member 79e in a state having an angle φ1. Part of the primary light 63 is diffused in various directions by the diffusing material and travels toward the first reflecting member 81. The remaining part of the primary light 63 is diffused by the diffusing material, then reflected by the fourth reflecting member 79f, diffused again by the diffusing material, and having a spreading angle larger than the angle φ1, the first reflecting member 81. Proceed toward. The primary light 63 is reflected by the first reflecting member 81 and enters the light conversion member 73.

  A part of the primary light 63 incident on the light conversion member 73 is absorbed by the light conversion member 73 and converted into the secondary light 65. The remaining part of the primary light 63 is emitted from the light conversion member 73 toward the emission surface 71 b without being absorbed by the light conversion member 73. The primary light 63 emitted from the incident surface 73a is reflected toward the light conversion member 73 by the first reflecting member 81, and the above-described operation is repeated again.

  A part of the secondary light 65 is emitted from the light conversion member 73 toward the emission surface 71b. The remaining part of the secondary light 65 is emitted from the incident surface 73 a toward the first reflecting member 81, is reflected by the first reflecting member 81, and passes through the light conversion member 73. The secondary light 65 is mixed with the primary light 63 emitted from the light conversion member 73 without being absorbed by the light conversion member 73, and is emitted from the emission surface 71 b as illumination light 67.

[effect]
In the present embodiment, the configuration of the course changing member 79 can be simplified, and the course changing member 79 can be easily manufactured. In this embodiment, since the primary light 63 is diffused by the diffusing member 79e, the primary light 63 can surely travel to the first reflecting member 81. The primary light 63 that has not been diffused can be reliably reflected toward the first reflective member 81 by the fourth reflective member 79f.

  In the present embodiment, the course changing member 79 may include only the diffusion member 79e.

[First Modification]
A first modification of the second embodiment will be described with reference to FIG. 5B. In this modification, only the parts different from the second embodiment will be described.
[Constitution]
The transparent member 71 spreads in a parabolic shape from the emitting portion 59 (incident surface 71a) toward the emitting surface 71b.
The first reflecting member 81 is disposed on the curved outer peripheral surface of the transparent member 71 and spreads in a parabolic shape from the emitting portion 59 toward the emitting surface 71b. The material of the first reflecting member 81 in this modification is the same as the material of the first reflecting member 81 in the first embodiment. The first reflecting member 81 reflects the primary light 63 substantially parallel to the optical axis 61 and reflects the primary light 63 toward a region other than the intensity region 93.

  In order to make the illumination light 67 substantially parallel to the optical axis 61, the light conversion member 73 is preferably disposed at a predetermined position in the vicinity of the emitting portion 59. The light conversion member 73 is disposed avoiding the focal position of the first reflecting member 81. As a result, the primary light 63 reflected by the first reflecting member 81 is irradiated to the light conversion member 73 substantially parallel avoiding at least the periphery of the optical axis 61, and the generated illumination light is also substantially parallel by the first reflecting member 81. Emitted.

[Action]
The primary light 63 emitted from the emission part 59 is transmitted through the transparent member 71 and incident on the diffusion member 79e in a state having an angle φ1. Part of the primary light 63 is diffused in various directions by the diffusing material and travels toward the first reflecting member 81. The remaining part of the primary light 63 is reflected by the fourth reflecting member 79f, diffused again by the diffusing material, and travels toward the first reflecting member 81 in a state of having a spread angle larger than the angle φ1. The primary light 63 is reflected substantially parallel to the optical axis 61 by the first reflecting member 81 and enters the light conversion member 73. The primary light 63 traveling substantially parallel to the optical axis 61 is referred to as parallel light.

  Part of the parallel light incident on the light conversion member 73 is absorbed by the light conversion member 73 and converted into the secondary light 65. The remaining part of the parallel light is not absorbed by the light conversion member 73 but is emitted from the back surface 73b toward the emission surface 71b. Parallel light (not shown) emitted from the incident surface 73a is reflected by the first reflecting member 81 toward the light conversion member 73, and the above-described operation is repeated again.

  A part of the secondary light 65 is emitted substantially parallel to the optical axis 61 from the back surface 73b toward the emission surface 71b. The remaining part of the secondary light 65 is emitted toward the first reflecting member 81 from the incident surface 73a. The secondary light 65 is reflected by the first reflecting member 81 toward the light conversion member 73 substantially parallel to the optical axis 61 and passes through the light conversion member 73. The secondary light 65 substantially parallel to the optical axis 61 emitted from the back surface 73 b is mixed with the parallel light emitted from the back surface 73 b without being absorbed by the light conversion member 73, and is substantially the same as the optical axis 61. The light is emitted from the emission surface 71 b as parallel illumination light 67.

[effect]
In the present modification, since the first reflecting member 81 is parabolic, the spread angle of the illumination light 67 can be suppressed, and the illumination light 67 substantially parallel to the optical axis 61 can be provided.

[Second Modification]
A second modification of the second embodiment will be described with reference to FIG. 5C. In this modification, only the parts different from the second embodiment will be described.
[Constitution]
The transparent member 71 spreads in a horn shape from the emitting portion 59 (incident surface 71a) toward the emitting surface 71b.
The first reflecting member 81 is disposed on the curved outer peripheral surface of the transparent member 71 and spreads in a horn shape from the emitting portion 59 toward the emitting surface 71b. The material of the first reflecting member 81 in this modification is the same as the material of the first reflecting member 81 in the first embodiment. The first reflecting member 81 reflects the primary light 63 toward a region other than the intensity region 93.

  The light conversion member 73 is disposed at a focal position where the horn-shaped transparent member 71 spreads.

[Action]
The primary light 63 emitted from the emission part 59 is transmitted through the transparent member 71 and incident on the diffusion member 79e in a state having an angle φ1. Part of the primary light 63 is diffused in various directions by the diffusing material and travels toward the first reflecting member 81. The remaining part of the primary light 63 is reflected by the fourth reflecting member 79f, diffused again by the diffusing material, and travels toward the first reflecting member 81 in a state of having a spread angle larger than the angle φ1. The primary light 63 is reflected by the first reflecting member 81 and enters the light converting member 73. At this time, by increasing the optical path length of the primary light 63, the irradiation area of the primary light 63 is widened, and the intensity distribution of the primary light 63 indicated by a solid line in FIG. 4C is further expanded from the donut-shaped intensity distribution. Specifically, the angle φ0 shown in FIG. 4C is further expanded than the angle φ0 ′, and the intensity of the primary light 63 in the intensity region 93 (thermal degradation region 93a) is greatly reduced. The intensity of the primary light 63 in the area is greatly increased, and the intensity distribution in the irradiated area becomes substantially uniform.

  A part of the primary light 63 incident on the light conversion member 73 is absorbed by the light conversion member 73 and converted into the secondary light 65. The remaining part of the primary light 63 is emitted from the light conversion member 73 toward the emission surface 71 b without being absorbed by the light conversion member 73. The primary light 63 emitted from the incident surface 73a is reflected toward the light conversion member 73 by the first reflecting member 81, and the above-described operation is repeated again.

  A part of the secondary light 65 is emitted from the light conversion member 73 toward the emission surface 71b. Although not shown, the remaining part of the secondary light 65 is emitted from the incident surface 73 a toward the first reflecting member 81, reflected by the first reflecting member 81, and transmitted through the light conversion member 73. Then, the secondary light 65 is mixed with the primary light 63 emitted from the light conversion member 73 without being absorbed by the light conversion member 73, and is emitted as illumination light 67 having a widening angle and a substantially uniform intensity distribution. The light is emitted from the surface 71b.

[effect]
In the present modification, since the first reflecting member 81 has a horn shape, the light distribution characteristic of the illumination light 67 can be changed, specifically, the spread angle of the illumination light 67 can be expanded. In this modification, it is possible to provide the illumination light 67 having a weak directivity and a substantially uniform intensity distribution.

[Third Embodiment]
The third embodiment will be described with reference to FIG. In the present embodiment, only the parts different from the first embodiment will be described.

[Constitution]
The course changing member 79 includes a fifth reflecting member 79g disposed between the emitting portion 59 and the light converting member 73 in the direction of the optical axis 61, and an irregular reflecting portion 79h that is at least a part of the surface of the fifth reflecting member 79g. Have

  The fifth reflecting member 79g is disposed at least around the optical axis 61. The fifth reflecting member 79 g has a high reflectance with respect to the wavelength of the primary light 63. The fifth reflecting member 79g has wavelength selectivity. The fifth reflecting member 79g is, for example, a dielectric multilayer film.

  The irregular reflection portion 79 h faces the emission portion 59. The irregular reflection portion 79h is disposed at least around the optical axis 61, and is disposed coaxially with the intensity region 93 in the optical axis 61 direction. The surface of the fifth reflecting member 79g, which is the irregular reflection portion 79h, has an uneven shape, and the height, size, or period of the unevenness is irregular.

  Since the intensity of the primary light 63 in the intensity region 93 is reduced and the intensity of the primary light 63 in the region other than the intensity region 93 is increased, the height of the unevenness is at least in the intensity region 93. It is below the wavelength. Therefore, the loss of light at the interface having a difference in refractive index is reduced, and the primary light 63 is scattered by the irregular reflection portion 79h.

  As a method of forming the unevenness, in the diffraction grating pattern creation corresponding to the wavelength of the primary light 63 created by the interference exposure pattern in the semiconductor process, multiple exposures in which the direction of the interference wavelength or the pitch of the diffraction grating is changed are used. Create with non-uniform spacing.

[Action]
The primary light 63 emitted from the emission part 59 is transmitted through the transparent member 71 and incident on the fifth reflecting member 79g in a state having an angle φ1. Part of the primary light 63 is diffusely reflected by the irregular reflection portion 79 h and travels toward the first reflecting member 81. The remaining part of the primary light 63 is reflected by the fifth reflecting member 79g, is diffusely reflected again by the irregular reflecting portion 79h, and travels toward the first reflecting member 81. The primary light 63 is reflected by the first reflecting member 81 and enters the light conversion member 73. And illumination light 67 is radiate | emitted from the output surface 71b similarly to 1st Embodiment.

[effect]
In this embodiment, since the unevenness of the irregular reflection portion 79h is easy to manufacture, the configuration of the course changing member 79 can be simplified, and the course changing member 79 can be easily manufactured.

  The present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment.

Claims (23)

A part of the optical characteristics of the primary light emitted from the light emission unit of the light source unit toward the illumination unit is converted by the light conversion member of the illumination unit to generate secondary light, and the illumination light is converted into the illumination unit. An illumination device that emits light from an exit surface,
The central axis of the primary light emitted from the emission part is defined as an optical axis,
When it is assumed that the light conversion member is directly irradiated with the primary light emitted from the emission part, an irradiation region irradiated with the primary light in the light conversion member is defined as a first irradiation region, In the first irradiation area, an area where the intensity of the primary light is a predetermined value or more is defined as an intensity area,
Disposed in the lighting unit, reducing at least the intensity of the primary light in the intensity region, and distributing the reduced intensity of the primary light to a region other than the intensity region in the light conversion member; A distribution unit that spreads the irradiation area into a second irradiation area wider than the first irradiation area by distribution;
The dispensing unit is
A course changing member that is disposed at least in the intensity region and changes a traveling direction of at least a part of the primary light in order to reduce the intensity of the primary light in at least the intensity region;
The primary light whose traveling direction has been changed by the path changing member is reflected toward the exit surface, and the secondary light traveling in a direction opposite to the exit surface is reflected toward the exit surface. A first reflecting member;
A lighting device comprising: The light conversion member is disposed between the emission part and the emission surface in the optical axis direction,
The first irradiation region and the second irradiation region including the intensity region are disposed on a plane facing the emitting portion and disposed on an incident surface of the light conversion member on which the primary light is incident,
The lighting device according to claim 1, wherein the path changing member reflects or diffuses at least a part of the primary light toward the first reflecting member.   The lighting device according to claim 2, wherein the first reflecting member is disposed from the emitting portion to the emitting surface in the optical axis direction, and is disposed so as to surround the light conversion member and the route changing member. The course changing member has a right conical or hemispherical optical member,
The lighting device according to claim 3, wherein the optical member reflects the primary light on a surface of the optical member. The illumination unit has a transparent member disposed between the emitting portion and the optical member in the optical axis direction,
The lighting device according to claim 4, wherein a refractive index of the transparent member is larger than a refractive index of the optical member.   When the incident angle of the primary light incident on the conical tip of the conical optical member is larger than a critical angle determined by the refractive index of the transparent member and the refractive index of the optical member, the optical member The illumination device according to claim 5, wherein the primary light is totally reflected. The lighting device according to claim 1, wherein the predetermined value is 1 / e ² with respect to a peak value of the intensity of the primary light.   The path changing member is disposed on a surface of the conical optical member, and is disposed to be inclined with respect to the optical axis, and a second reflecting member that reflects the primary light toward the first reflecting member. The lighting device according to claim 5.   When the incident angle of the primary light incident on the conical tip of the conical optical member is smaller than the critical angle, the second reflecting member is disposed at least from the optical axis to a region where the incident angle is a critical angle. The lighting device according to claim 8. The first reflecting member extends in a tapered shape from the emitting portion toward the emitting surface,
The angle formed between the conical bus of the optical member and the optical axis is such that the primary light traveling toward the bus travels to the first reflecting member at the same reflection angle as the angle of incidence on the bus. Thus, the illuminating device of Claim 5 smaller than the angle formed between the said bus-line and the entrance plane of the said light conversion member. An angle formed between the primary light emitted from the emission part and the optical axis is φ1,
With the central axis of the optical member being disposed on the optical axis, an angle formed between the bus and the optical axis is φ2,
When the primary light is incident on the optical member with the angle φ1, the incident angle of the primary light with respect to the normal at the incident position of the optical member is ψ1,
When the primary light is refracted by the optical member and then passes through the optical member, a refraction angle formed between the refracted primary light and the optical axis is ψ2,
The refractive index of the transparent member is n1,
The refractive index of the optical member is n2,
Then,
Under the condition of n2 <n1 and 0 ≦ φ1 ≦ φ2,
Equations (1) and (2) hold,
n1 × sin ψ1 = n2 × sin ψ2 Expression (1)
ψ1 = π / 2− (φ2−φ1) (2)
Formula (3) is satisfied because the angle φ2 is smaller than the angle formed between the bus and the incident surface of the light conversion member,
2ψ1 <π / 2 + φ2 Formula (3)
Equation (4) is satisfied because the primary light is reflected by the optical member and travels to the first reflecting member. Π / 6 + 2 / 3φ1 <φ2 (Equation (4))
The lighting device according to claim 10. The course changing member is
A third reflecting member disposed on the surface of the hemispherical optical member;
An irregular reflection portion that is at least part of the surface of the third reflecting member and is disposed at least around the optical axis;
Have
The illuminating device according to claim 5, wherein the surface of the third reflecting member which is the irregular reflection portion has an uneven shape, and the height, size, or period of the unevenness is irregular.   The lighting device according to claim 3, wherein the route changing member includes a columnar diffusion member that diffuses the primary light.   The lighting device according to claim 13, wherein the path changing member includes a fourth reflecting member that is disposed between the diffusing member and the light converting member in the optical axis direction and reflects the primary light.   The lighting device according to claim 4, wherein the first reflecting member extends in a tapered shape from the emitting portion toward the emitting surface. An angle formed between the primary light emitted from the emission part and the optical axis is φ1,
With the central axis of the optical member disposed on the optical axis, an angle formed between the optical axis and the generatrix of the conical generating member is φ2,
An angle formed between the tapered first reflecting member and the optical axis direction is φ3,
Defined as
The lighting device according to claim 15, wherein φ1 <φ3 <φ2.   The lighting device according to claim 3, wherein the first reflecting member has a parabolic shape or a horn shape, and reflects the primary light to the light conversion member in a portion excluding the periphery of the optical axis. The course changing member is
A fifth reflecting member disposed between the emitting portion and the light converting member in the optical axis direction;
An irregular reflection portion that is at least part of the surface of the fifth reflecting member and is disposed at least around the optical axis;
Have
The lighting device according to claim 3, wherein the surface of the fifth reflecting member that is the irregular reflection portion has an uneven shape, and the height, size, or period of the unevenness is irregular.   The lighting device according to claim 1, wherein the light conversion member includes a wavelength conversion member that converts the wavelength of the primary light to generate the secondary light.   The lighting device according to claim 1, wherein the light conversion member includes a diffusion member that diffuses the primary light to generate the secondary light.   The illuminating device according to claim 1, wherein the illumination unit is optically connected to the emission unit disposed in a light guide member that guides the primary light emitted from the light source of the light source unit.   The illuminating device according to claim 1, wherein the illuminating unit is disposed in a light source of the light source unit and is optically connected to the emitting unit that emits the primary light. An endoscope,
A light source unit having an emission part for emitting primary light;
The illuminating device according to claim 1, which is disposed in the endoscope,
An endoscope system comprising:

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