JP7047240B2 - Lighting equipment - Google Patents

Description

The present invention relates to a lighting device that utilizes light emitted from a light source that emits a small amount of etendue light as illumination light.

For example, a large number of lighting light sources that emit light via an optical fiber have been developed and can be used (Patent Document 1, Non-Patent Document 1, Non-Patent Document 2, Non-Patent Document 3). These light sources can be considered as point light sources (point radiation sources). The etandue of the emitted light from these light sources is small. The application of such a light source to a lighting device is being studied (Patent Documents 2 and 3).

Japanese Unexamined Patent Publication No. 2005-205195 Japanese Unexamined Patent Publication No. 2011-243373 Japanese Unexamined Patent Publication No. 2012-234846 Japanese Unexamined Patent Publication No. 2011-049076 Japanese Unexamined Patent Publication No. 2017-059543

High-power white laser module "NEON BOX", Internet (URL: https://www.ushio.co.jp/jp/products/1031.html) RGB-One (registered trademark) full-color laser module, Internet (URL: http://www.sei.co.jp/products/laser-module/pdf/JSP008.pdf) NecselTM RGB NovaLum 1200, Internet (URL: http://necsel.com/pdf/NovaLum-1200-Prelim.pdf)

When the above light source is used as illumination light, the brightness of the light source is higher than the brightness of what the human eye sees (object to be seen, object to be viewed) when the light source enters the field of view. For this reason, there may be concerns that the object may be difficult to see (reduced glare) or that the object may feel unpleasant (unpleasant glare).

Further, when the light distribution characteristics of the light source are represented by a Cartesian coordinate system in which the horizontal axis is the angle and the vertical axis is the light intensity, the light source may have a characteristic that the light intensity gradually decreases as the distance from the optical axis is increased with the optical axis as the center. In such a case, for example, when the headlight for a vehicle is used, the light-dark boundary line between the range to be irradiated and the range not to be irradiated is not clear, which may cause glare to the oncoming vehicle. Further, for example, when used for signboard lighting, light protruding from the signboard may cause light pollution.

The present invention provides a lighting device capable of suppressing glare with a configuration in which the number of parts is reduced.

According to one aspect of the present invention, the lighting device has a light source, a central portion, and a peripheral portion having a refractive index lower than the refractive index of the central portion, and guides light from the light source. It includes a portion, a reflecting member, and a translucent member provided at the light emitting end of the light guide portion and transmitting light emitted from the light guide portion. The translucent member has a first light reflecting surface that reflects light emitted from the light guide portion. The reflecting member has a second light reflecting surface to which light reflected by the first light reflecting surface is incident and emits the incident light forward. An intersection of a plane including the optical axis of the light guide portion, a normal having the first light reflecting surface, and a normal having the second light reflecting surface, and the first light reflecting surface. Is a part of the first conical curve, and the intersection line between the plane and the second light reflecting surface is a part of the second conical curve.

According to one aspect of the present invention, glare can be suppressed by a configuration in which the number of parts is reduced.

It is a schematic cross-sectional view of the lighting apparatus of 1st Embodiment. It is a schematic cross-sectional view of the lighting apparatus of 2nd Embodiment. It is a schematic cross-sectional view of the lighting apparatus of 2nd Embodiment. It is a schematic cross-sectional view of the lighting apparatus of 3rd Embodiment. It is a schematic front view seen from the light emission side of the light guide part and the light-transmitting member in the lighting apparatus of 3rd Embodiment. It is a schematic front view seen from the light emission side of the light guide part and the light-transmitting member in the lighting apparatus of 3rd Embodiment. It is a schematic cross-sectional view of the lighting apparatus of 4th Embodiment. It is a schematic cross-sectional view of the lighting apparatus of 5th Embodiment. It is a schematic cross-sectional view of the lighting apparatus of 6th Embodiment. It is a schematic cross-sectional view of the lighting apparatus of 7th Embodiment. It is a schematic cross-sectional view of the lighting apparatus of 8th Embodiment. It is a schematic cross-sectional view of the lighting apparatus of 9th Embodiment. It is a schematic front view seen from the light emission side of the lighting apparatus of 9th Embodiment.

Hereinafter, embodiments (embodiments) for carrying out the present invention will be described with reference to the drawings as appropriate. However, the lighting device described below is for embodying the technical idea of the present invention, and the present invention is not limited to the following unless otherwise specified. Moreover, the contents described in each of the plurality of embodiments are applicable to each other. Among the configurations described in the plurality of embodiments, those given the same name indicate members of the same or the same quality, and detailed description thereof will be omitted as appropriate. In order to facilitate the explanation, the size and positional relationship of the members shown in each drawing may be exaggerated, and the illustration may be omitted.

The lighting device of one embodiment includes a light source, a light guide unit, a reflecting member, and a translucent member. The light guide portion has a central portion (core portion) and a peripheral portion (clad portion) having a refractive index lower than that of the central portion, and guides light from a light source. The light transmitting member is provided at the light emitting end of the light guide portion and transmits the light emitted from the light guide portion. The translucent member has a first light reflecting surface that reflects light emitted from the light guide portion. The reflecting member has a second light reflecting surface to which light reflected by the first light reflecting surface is incident and emits the incident light forward. The light-transmitting member can further have a first light-transmitting surface orthogonal to a light beam traveling from the first light-reflecting surface to the second light-reflecting surface. Here, the front represents the front in the traveling direction of the light emitted from the light guide unit. The angle between the optical axis of the light emitted from the light guide and the optical axis of the light emitted from the lighting device is less than 90 degrees.

Alternatively, the lighting device of another embodiment is provided at a light source, a light guide unit that guides light from the light source, and a light emitting end of the light guide unit, and transmits light emitted from the light guide unit. It is equipped with a member. The translucent member has a first light reflecting surface that reflects the light emitted from the light guide portion and a second light reflection that the light reflected by the first light reflecting surface is incident and emits the incident light forward. Has a face. The translucent member can further have a second light transmitting surface orthogonal to the light beam reflected by the second light reflecting surface.

The light in each embodiment is light for illumination and is mainly visible light, but may also include near-ultraviolet rays and near-infrared rays.

As the light source, for example, a light source that emits light via the optical fiber described in Patent Document 1, Non-Patent Document 1, Non-Patent Document 2, and Non-Patent Document 3 can be used. Not limited. Small light bulbs, light emitting diodes, various lasers, and / or combinations of these with light guide paths (eg, optical fibers, light guide rods, light guide plates, light guides, light guides, etc.) can be light sources in embodiments. The projected shape of the light source is not limited to a circle, but may be a rectangle, a polygon, or a line. An optical connector can be appropriately provided at the tip of a light guide path such as an optical fiber in order to connect to a lighting device. The spread of light emitted from the light source can be controlled by the structure of the light guide path at the exit end. For example, when an optical fiber is used as a light guide path, the spread of light emitted from the light source depends on the numerical aperture of the optical fiber.

The light guide portion may have a core portion, a clad portion surrounding the core portion, and a covering portion surrounding the clad portion. The interface between the clad portion and the covering portion can be a mirror surface. The clad portion and the covering portion may be omitted. An optical connector can be used to connect the light guide unit and the light source. For example, a plug or jack may be provided on the light source side, and a receptacle corresponding to the plug or jack may be provided on the light guide portion side.

It is preferable that the numerical aperture of the light guide portion on the light source side is equal to or larger than the numerical aperture of the light source in order to increase the optical coupling efficiency between the light source and the light guide portion. The numerical aperture of the light guide portion on the translucent member side is preferably small in order to reduce the size of the lighting device. The numerical aperture of the light guide portion on the light source side and the numerical aperture on the translucent member side are, for example, 0.5 or less.

The translucent member in one embodiment may have a first light reflecting surface and a first light transmitting surface.
Further, the translucent member in another embodiment may have a first light reflecting surface, a second light reflecting surface, and a second light transmitting surface.
Further, the translucent member in one embodiment includes a first light reflecting surface, a first light transmitting surface, a third light reflecting surface, a fourth light reflecting surface, and a fourth light transmitting surface. And can have.
Further, the light-transmitting member in another embodiment includes a first light-reflecting surface, a second light-reflecting surface, a second light-transmitting surface, a third light-reflecting surface, and a third light-transmitting surface. And can have.
Further, the translucent member in one embodiment may have a first light reflecting surface, a first light transmitting surface, a third light reflecting surface, and a third light transmitting surface.
Further, the translucent member in another embodiment includes a first light reflecting surface, a second light reflecting surface, a second light transmitting surface, a third light reflecting surface, and a fourth light reflecting surface. And a fourth light transmitting surface.

A part of the surface of the translucent member in the traveling direction of the light emitted from the light guide portion functions as the first light reflecting surface. A light reflecting film can be provided on at least a part of the surface of the translucent member that functions as the first light reflecting surface. This is preferable because the light transmission loss on the first light reflecting surface can be further suppressed. The light reflecting film may be, for example, a metal film of Al, Ag, Pt, Au, Cr, or an alloy thereof. Further, the light reflecting film may be, for example, a multilayer film made of two or more kinds of dielectrics (for example, two kinds selected from TiO ₂ , Ta ₂ O ₅ , Al ₂ O ₃ , SiO ₂ , MgF ₂ , etc.). However, a combination of a metal film and a dielectric film may be used. By providing such a light reflecting film, it is possible to reduce the absorption loss of light on the first light reflecting surface and suppress the influence of heat. When the angle of incidence on the first light reflecting surface satisfies the total reflection condition, the light reflecting film does not have to be on the first light reflecting surface. As an example in which the angle of incidence on the first light reflecting surface satisfies the total reflection condition, the refractive index (n) of the translucent member in the air and the angle of incidence on the first light reflecting surface (θ) are , The case where the following relational expression is satisfied can be mentioned.

sinθ ≧ 1 / n

The translucent member is made of a material having good transmittance (high transmittance) of light emitted from the light guide portion, for example, glass or plastic for an optical lens. The translucent member is preferably composed of a single member or a plurality of members having the same refractive index. This is because if the translucent member is composed of a plurality of members having different refractive indexes, the number of parts increases and light loss at the bonding interface occurs.

It is preferable that the translucent member and the light guide portion are directly bonded by a method such as welding with the same refractive index or adhesion with an optical adhesive. That is, it is preferable that the translucent member is made of a material having a refractive index equal to the average refractive index of the central portion of the light guide portion, and the translucent member and the light guide portion are joined. This makes it possible to suppress light loss at the joint surface.

The first light reflecting surface is a part of the surface of the translucent member. The first light reflecting surface can be designed in a desired shape. For example, when the light emitting end of the light guide can be close to a point, the first light reflecting surface is such that the line of intersection with the plane including the vertical cross section of the light guide is part of the conic section. be able to. Here, the conic section is any one of a two straight line, a hyperbola, a parabola, an ellipse, and a circle. In addition, a curve whose intersection line with the plane including the vertical cross section of the light guide is convex downward (for example, a part of a quadratic curve, a part of a catenary curve, a part of a cycloid, a part of an exponential curve, etc.). It may be set to. The first light reflecting surface may be a rotating surface or a curved surface orthogonal to a plane including a vertical cross section of the light guide portion. Further, the first light reflecting surface of the embodiment may be a combination of a flat surface and a curved surface.

The first light transmitting surface of one embodiment is a part of the surface of the light transmitting member. The first light transmitting surface is located between the first light reflecting surface and the second light reflecting surface, and transmits the light rays reflected by the first light reflecting surface. The first light transmitting surface can be designed to have a desired shape. The first light transmitting surface preferably has a low reflection film (also referred to as an antireflection film or an antireflection film) in a region through which light rays pass in order to suppress light reflection loss. The low-reflection film may be a single-layer film of a dielectric or a multilayer film composed of two or more kinds of dielectrics.

The second light reflecting surface of the other embodiment is a rotating surface when the first light reflecting surface is a rotating surface. Alternatively, when the first light reflecting surface is a plane, a curved surface, or a combination thereof, the second light reflecting surface is a plane, a curved surface, or a combination thereof.

The second light reflecting surface may be the surface of the reflecting member or the surface of the light reflecting film provided on the reflecting member, or may be a part of the surface of the translucent member.

The second light transmitting surface is a part of the surface of the light transmitting member. The second light transmitting surface transmits the light rays reflected by the second light reflecting surface. The second light transmitting surface can be designed in a desired shape. For example, when the light emitting end of the light guide unit can be approximated to a point, the optical axis of the light guide unit, the normal line having the first light reflecting surface, and the normal line having the second light reflecting surface are used. The intersection of the including plane and the second light reflecting surface can be made part of the conical curve. The second light transmitting surface preferably has a low reflection film in a region through which light rays pass in order to suppress light reflection loss.

The third light reflecting surface is a part of the surface of the translucent member. The third light reflecting surface can be designed in a desired shape. For example, when the light emitting end of the light guide can be approximated to a point, the third light reflecting surface is such that the line of intersection with the plane including the vertical cross section of the light guide becomes a part of the conic section. can do. In addition, a curve whose intersection line with the plane including the vertical cross section of the light guide is convex downward (for example, a part of a quadratic curve, a part of a catenary curve, a part of a cycloid, a part of an exponential curve, etc.). It may be set to. The third light reflecting surface may be a rotating surface or a curved surface orthogonal to a plane including a vertical cross section of the light guide portion. Further, the third light reflecting surface may be a combination of a flat surface and a curved surface. The shortest distance between the third light reflecting surface and the light guide portion is larger than the shortest distance between the first light reflecting surface and the light guide portion.

The third light transmitting surface is a part of the surface of the light transmitting member. The third light transmitting surface is located between the third light reflecting surface and the fourth light reflecting surface, and transmits the light rays reflected by the third light reflecting surface. The third light transmitting surface preferably has a low reflection film in a region through which light rays pass in order to suppress light reflection loss.

The fourth light reflecting surface is a rotating surface when the third light reflecting surface is a rotating surface. Alternatively, when the third light reflecting surface is a plane, a curved surface, or a combination thereof, the fourth light reflecting surface is a plane, a curved surface, or a combination thereof.

The fourth light reflecting surface may be the surface of the reflecting member or the surface of the light reflecting film provided on the reflecting member, or may be a part of the surface of the translucent member.

The fourth light transmitting surface is a part of the surface of the light transmitting member. The fourth light transmitting surface transmits the light rays reflected by the fourth light reflecting surface. The fourth light transmitting surface can be designed in a desired shape. For example, when the light emitting end of the light guide unit can be approximated to a point, the optical axis of the light guide unit, the normal line having the third light reflecting surface, and the normal line having the fourth light reflecting surface are used. The intersection of the including plane and the fourth light reflecting surface can be made part of the conical curve. The fourth light transmitting surface preferably has a low reflection film in a region through which light rays pass in order to suppress light reflection loss.

The beam expander expands the beam, that is, expands the diameter of the luminous flux. The beam expander may have at least an incident side optical element (for example, a concave lens) and an emitting side optical element (for example, a convex lens), or may have a special prism in which the incident side optical element and the emitting side optical element are integrated. You may have.

The light emitted from the light guide unit is incident on the first light reflecting surface and reflected, and then passes through the first light transmitting surface forming a part of the surface of the light transmitting member and the second light reflecting surface. Can be incident on. The first light transmitting surface preferably has a low reflection film. It is preferable that the first light transmitting surface is perpendicular to the light beam because it is easy to design and form a low-reflection film.

Further, the light emitted from the light guide unit may be incident on the first light reflecting surface and reflected, and then incident on the second light reflecting surface forming a part of the surface of the translucent member. In this case, it is preferable that at least a part of the surface of the translucent member functioning as the second light reflecting surface is provided with a light reflecting film. If the angle of incidence on the second light reflecting surface satisfies the total reflection condition, the light reflecting film may not be present. The light reflected by the second light reflecting surface passes through the second light transmitting surface forming a part of the surface of the translucent member and is emitted from the illuminating device. The second light transmitting surface preferably has a low reflection film. It is preferable that the second light transmitting surface is perpendicular to the light beam because it is easy to design and form a low-reflection film.

Further, a part of the light emitted from the light guide unit may be incident on the third light reflecting surface. The light incident on the third light reflecting surface is reflected by the third light reflecting surface, and then passes through the third light transmitting surface forming a part of the surface of the translucent member to pass through the fourth light reflecting surface. Can be incident on. It is preferable that the third light transmitting surface is provided with a low reflection film. It is preferable that the third light transmitting surface is perpendicular to the light beam because it is easy to design and form a low-reflection film.

Further, the light incident on the third light reflecting surface may be reflected by the third light reflecting surface and then incident on the fourth light reflecting surface forming a part of the surface of the translucent member. In this case, it is preferable that at least a part of the surface of the translucent member functioning as the fourth light reflecting surface is provided with a light reflecting film. If the angle of incidence on the fourth light reflecting surface satisfies the total reflection condition, the light reflecting film may not be present. The light reflected by the fourth light reflecting surface passes through the fourth light transmitting surface forming a part of the surface of the translucent member and is emitted from the illuminating device. It is preferable that the fourth light transmitting surface is provided with a low reflection film. It is preferable that the fourth light transmitting surface is perpendicular to the light beam because it is easy to design and form a low-reflection film.

The translucent member in another embodiment may have a lens portion that functions as a part of the beam expander in addition to the first light reflecting surface. It is preferable that the surface of the lens portion is provided with a low reflection film in order to suppress light loss.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the optical axis of the light emitted from the light guide portion (hereinafter referred to as “optical axis of the light guide portion”) is represented by a one-dot chain line. In addition, the light beam is represented by a broken line.

(First Embodiment)
FIG. 1 shows a schematic vertical sectional view of the lighting device 1 of the first embodiment.
In the present specification, the "vertical cross section" is a first direction along the optical axis of the light guide portion and a direction from the central portion (core portion) of the light guide portion to the peripheral portion (clad portion). Represents a cross section including a second direction orthogonal to a direction.
The lighting device 1 is axisymmetric with respect to the optical axis (dashed line) of the light guide unit. The lighting device 1 includes a light source 10, a light guide unit 20 that guides light from the light source 10, a light transmissive member 30 that transmits light emitted from the light guide unit 20, and a reflection member (or a second light reflection). It has (support) 41 of a light reflecting film that functions as a surface.

The light guide unit 20 is connected to the light source 10. The light source 10 includes, for example, an optical fiber 11, a wavelength conversion unit 12, and a heat dissipation unit 13 surrounding the wavelength conversion unit 12. The wavelength conversion unit 12 contains a fluorescent substance that is excited by the emitted light of the optical fiber 11 and emits light having a wavelength different from the emitted light. The emitted light of the optical fiber 11 is incident on the wavelength conversion unit 12, and at least a part of the light excites the fluorescent substance. The mixed light of the emitted light of the optical fiber 11 and the synchrotron radiation of the fluorescent substance is incident on the light guide unit 20. In addition, in FIGS. 2 and later, the illustration of the light source is omitted except for FIG.

The shape of the light guide portion 20 is a rotating body shape. The light guide portion 20 has a columnar core portion 21 and a clad portion 22 surrounding the core portion 21. The refractive index of the core portion 21 is higher than that of the clad portion 22. For example, assuming that the refractive index of the core portion 21 is 1.51633 and the refractive index of the clad portion 22 is 1.50, the numerical aperture of the light guide portion 20 on the light source side and the numerical aperture on the translucent member side are 0.222. be.

The light transmitting member 30 is directly joined to, for example, the light guide unit 20 and is provided at the light emitting end of the light guide unit 20. The translucent member 30 is supported by the light guide portion 20. The translucent member 30 is made of a material having a refractive index equal to the average refractive index of the clad portion 22. Alternatively, the translucent member 30 is made of a material having a refractive index equal to the average refractive index of the core portion 21. In this case, it is possible to suppress the reflection of the light emitted from the core portion 21 at the interface between the core portion 21 and the translucent member 30. The contour of the translucent member 30 seen from the light emitting side of the lighting device 1 is, for example, a circle.

The light transmitting member 30 has a first light reflecting surface 31 and a first light transmitting surface 33. A light reflecting film can be provided on the first light reflecting surface 31.

The reflecting member 41 includes a light reflecting film, and has a second light reflecting surface 42 to which light reflected by the first light reflecting surface 31 is incident and emits the incident light forward. Further, the light reflecting film 43 is also provided on the side surface of the clad portion 22 and the side surface of the portion of the translucent member 30 on the light guide portion 20 side.

The first light transmitting surface 33 is orthogonal to the light beam traveling from the first light reflecting surface 31 to the second light reflecting surface 42. This facilitates light transmittance control on the first light transmitting surface 33. A low reflection film can be provided on the first light transmitting surface 33.

The shapes of the first light reflecting surface 31 and the first light transmitting surface 33 can be appropriately designed so that desired irradiation light can be obtained. For example, the shape of the first light reflecting surface 31 may be a rotating surface of a parabola. The shape of the first light transmitting surface 33 may be a part of the side surface of the cylinder which is a rotating surface. The shape of the second light reflecting surface 42 may be a straight rotating surface. The axes of all rotating bodies and rotating surfaces coincide with the optical axis of the light guide.

In the vertical cross section (middle cross section) of the light guide unit 20, the light emitting end of the light guide unit 20 can be located at the focal point of the first light reflecting surface 31 (a part of the parabola). In the meridional cross section, the second light reflecting surface 42 can be a straight line forming 45 degrees with the optical axis of the light guide unit 20. In such a configuration, the light rays emitted from the illuminating device 1 can be aligned in parallel. For example, if the translucent member 30 is made of a material having a refractive index of 1.42 or more (for example, optical glass such as crown glass or optical plastic such as polymethyl methacrylate resin), the total reflection condition is satisfied. Therefore, it is not necessary to provide a light reflecting film on the first light reflecting surface.

According to the first embodiment, since the translucent member 30 has the first light reflecting surface 31, glare can be suppressed with a configuration in which the number of parts is reduced. Further, the depth size of the lighting device 1 can be suppressed.

(Second Embodiment)
FIG. 2 shows a schematic vertical sectional view of the lighting device 2 of the second embodiment.
The lighting device 2 is axisymmetric with respect to the optical axis (dashed line) of the light guide unit. The lighting device 2 includes a light source (not shown), a light guide unit 20, a light transmitting member 30, and a reflecting member 41.

The translucent member 30 of the illuminating device 2 is the same as the illuminating device 1 of the first embodiment, but the shapes of the first light reflecting surface 31 and the first light transmitting surface 33 are different.

In the example shown in FIG. 2, the shape of the first light reflecting surface 31 is a linear rotating surface forming 45 degrees with the optical axis of the light guide unit 20. The shape of the first light transmitting surface 33 is a rotating surface orthogonal to the light rays reflected by the first light reflecting surface 31, and the normal of the rotating surface is the light rays reflected by the first light reflecting surface 31. Matches with. The shape of the second light reflecting surface 42 is a rotating surface of a parabola. The mirror image point of the light emitting end of the light guide unit 20 having the first light reflecting surface 31 as the plane of symmetry can be located at the focal point of the second light reflecting surface 42. As a result, the light rays reflected and emitted by the second light reflecting surface 42 can be aligned in parallel.

That is, a plane including the optical axis of the light guide unit 20, a normal having the first light reflecting surface 31, and a normal having the second light reflecting surface 42, and the first light reflecting surface 31. The intersection line is a straight line, and the intersection line between the plane and the second light reflecting surface 42 is a part of the parabolic line.

Also in the second embodiment, as in the above-mentioned lighting device 1, glare can be suppressed and the depth size of the lighting device 2 can be suppressed by the configuration in which the number of parts is suppressed.

In the second embodiment, as shown in FIG. 3, the size of the irradiation region by the lighting device 2 can be changed by moving the reflection member 41 having the second light reflection surface 42 in the optical axis direction of the light guide unit 20. Can be. That is, the distance between the first light reflecting surface 31 and the second light reflecting surface 42 in the optical axis direction of the light emitted from the light guide unit 20 is variable. The light rays emitted from the illuminating device 2 can be aligned in parallel, and can be focused or diverged. As a means for moving the reflective member 41 in the optical axis direction of the light guide unit 20, for example, a donut-shaped permanent magnet is provided on the neck of the funnel-shaped reflective member 41 on the outside of the light guide unit 20, and an electromagnet is provided in the vicinity of the outside thereof. There may be an electromagnetic means of providing a coil and allowing the current of the coil to flow. Further, it may be a mechanical means by a combination of a spring and a cam.

(Third Embodiment)
FIG. 4 shows a schematic vertical sectional view of the lighting device 3 of the third embodiment.
The lighting device 3 includes a light source (not shown), a light guide unit 23 that guides light from the light source, a light transmissive member 60 that transmits light emitted from the light guide unit 23, and a reflection member (or a second). 46, which is a support for a light-reflecting film that functions as a light-reflecting surface of the above.

The light guide portion 23 has a core portion 24 and a clad portion 25 that surrounds the core portion 24 or is sandwiched from above and below along the second direction. The refractive index of the core portion 24 is higher than that of the clad portion 25.

The light guide unit 23 is formed in a plate shape, for example, and the shape of the light guide unit 23 seen from the light emitting side of the lighting device 3 is, for example, a quadrangle as shown in FIG. Alternatively, the shape of the light guide unit 23 as seen from the light emitting side of the lighting device 3 is, for example, a semicircular shape as shown in FIG.

The light transmitting member 60 is directly joined to, for example, the light guide portion 23, and is provided at the light emitting end of the light guide portion 23. The translucent member 60 is made of a material having a refractive index equal to the average refractive index of the clad portion 25. Alternatively, the translucent member 60 is made of a material having a refractive index equal to the average refractive index of the core portion 24.

As shown in FIG. 5, the contour of the translucent member 60 seen from the light emitting side of the lighting device 3 is, for example, a quadrangle. Alternatively, the contour of the translucent member 60 seen from the light emitting side of the lighting device 3 is, for example, circular as shown in FIG.

As shown in FIG. 4, the translucent member 60 has a first light reflecting surface 61 and a first light transmitting surface 63. A light reflecting film can be provided on the first light reflecting surface 61.

The reflecting member 46 includes a light reflecting film, and has a second light reflecting surface 42 to which light reflected by the first light reflecting surface 61 is incident and emits the incident light forward.

The first light transmitting surface 63 is orthogonal to a light ray traveling from the first light reflecting surface 61 to the second light reflecting surface 42. This facilitates light transmittance control on the first light transmitting surface 63. A low reflection film can be provided on the first light transmitting surface 63.

In the example shown in FIG. 4, the first light reflecting surface 61 is a part of a parabola, and the second light reflecting surface 42 is a straight line forming 45 degrees with the optical axis of the light guide unit 23. In such a configuration, the light rays emitted from the illuminating device 3 can be aligned in parallel.

Also in the third embodiment, since the translucent member 60 has the first light reflecting surface 61, glare can be suppressed by the configuration in which the number of parts is suppressed. Further, the depth size of the lighting device 3 can be suppressed.

(Fourth Embodiment)
FIG. 7 shows a schematic vertical sectional view of the lighting device 4 of the fourth embodiment.
The lighting device 4 is axisymmetric with respect to the optical axis (dashed line) of the light guide unit. The lighting device 4 has a light source (not shown), a light guide unit 20, and a translucent member 30 that transmits light emitted from the light guide unit 20.

The light transmitting member 30 is directly joined to, for example, the light guide unit 20 and is provided at the light emitting end of the light guide unit 20. The translucent member 30 is made of a material having a refractive index equal to the average refractive index of the clad portion 22. Alternatively, the translucent member 30 is made of a material having a refractive index equal to the average refractive index of the core portion 21. The contour of the translucent member 30 seen from the light emitting side of the lighting device 4 is, for example, a circle.

The light transmitting member 30 has a first light reflecting surface 31, a second light reflecting surface 32, and a second light transmitting surface 34. A light reflecting film can be provided on the first light reflecting surface 31 and the second light reflecting surface 32.

The second light transmitting surface 34 is orthogonal to the light rays reflected by the second light reflecting surface 32. This facilitates light transmittance control on the second light transmitting surface 34. A low reflection film can be provided on the second light transmitting surface 34.

In the example shown in FIG. 7, the shape of the first light reflecting surface 31 can be assumed to be a parabolic rotating surface. It can be assumed that the shape of the second light reflecting surface 32 is a straight rotating surface. It can be assumed that the shape of the second light transmitting surface 34 is a donut-shaped plane which is a straight rotating surface. The axes of all rotating bodies and rotating surfaces coincide with the direction of the center of the optical axis of the light guide.

In such a configuration, the light rays emitted from the lighting device 4 can be aligned in parallel in the same manner as the lighting device 1 described above.

According to the fourth embodiment, since the translucent member 30 has the first light reflecting surface 31 and the second light reflecting surface 32, glare can be suppressed with a configuration in which the number of parts is further reduced. Further, the depth size of the lighting device 4 can be suppressed.

Further, the light reflected by the first light reflecting surface 31 passes through the inside of the light transmitting member 30 and is incident on the second light reflecting surface 32 without going out to the outside of the light transmitting member 30. This makes it possible to reduce the light density of the light transmitting surface and suppress light collection.

(Fifth Embodiment)
FIG. 8 shows a schematic vertical sectional view of the lighting device 5 of the fifth embodiment.
The lighting device 5 is axisymmetric with respect to the optical axis (dashed line) of the light guide unit. The lighting device 5 includes a light source (not shown), a light guide unit 20, and a translucent member 30 that transmits light emitted from the light guide unit 20.

The translucent member 30 of the lighting device 5 is the same as the above-mentioned lighting device 4, but the shapes of the first light reflecting surface 31 and the second light reflecting surface 32 are different.

In the example shown in FIG. 8, the shape of the first light reflecting surface 31 is a linear rotating surface forming 45 degrees with the optical axis of the light guide unit 20. The shape of the second light reflecting surface 32 is a rotating surface of a parabolic line, and the mirror image point of the light emitting end of the light guide unit 20 having the first light reflecting surface 31 as a plane of symmetry is the second light reflecting surface 32. Can be located at the focal point of. The shape of the second light transmitting surface 34 is a rotating surface orthogonal to the light rays reflected by the second light reflecting surface 32, and the normal of the rotating surface is reflected by the second light reflecting surface 32. It can be aligned with the rays and be a donut-shaped plane. In such a configuration, the light rays emitted from the illuminating device 5 can be aligned in parallel.

That is, a plane including the optical axis of the light guide unit 20, a normal having the first light reflecting surface 31, and a normal having the second light reflecting surface 32, and the first light reflecting surface 31. The intersection line is a straight line, and the intersection line between the plane and the second light reflecting surface 32 is a part of the parabolic line.

According to the fifth embodiment, as in the lighting device 4 described above, glare can be suppressed by a configuration in which the number of parts is further reduced. Further, the depth size of the lighting device 5 can be suppressed. Furthermore, it suppresses light dust collection.

(Sixth Embodiment)
FIG. 9 shows a schematic vertical sectional view of the lighting device 6 of the sixth embodiment.
The lighting device 6 has a light source (not shown), a light guide unit 23, and a translucent member 60 that transmits light emitted from the light guide unit 23.

The shape of the light guide portion 23 of the lighting device 6 and the contour of the translucent member 60 are the same as in the case of the lighting device 3 described above.

The light transmitting member 60 has a first light reflecting surface 61, a second light reflecting surface 62, and a second light transmitting surface 64. A light reflecting film can be provided on the first light reflecting surface 61 and the second light reflecting surface 62.

The second light transmitting surface 64 is orthogonal to the light rays reflected by the second light reflecting surface 62. This facilitates light transmittance control on the second light transmitting surface 64. A low reflection film can be provided on the second light transmitting surface 64.

In the example shown in FIG. 9, the first light reflecting surface 61 is a straight line forming 45 degrees with the optical axis of the light guide unit 23, and the second light reflecting surface 62 can be a part of a parabola. In such a configuration, the light rays emitted from the illuminating device 6 can be aligned in parallel.

That is, the optical axis of the light guide unit 23, the plane including the normal with the first light reflecting surface 61, the normal with the second light reflecting surface 62, and the first light reflecting surface 61. The intersection line is a straight line, and the intersection line between the plane and the second light reflecting surface 62 is a part of the parabolic line.

According to the sixth embodiment, glare can be suppressed and the depth size can be suppressed as in the third embodiment described above.

Further, the light reflected by the first light reflecting surface 61 passes through the inside of the light transmitting member 60 and is incident on the second light reflecting surface 62 without going out of the light transmitting member 60. This makes it possible to reduce the light density of the light transmitting surface and suppress light collection.

(7th Embodiment)
FIG. 10 shows a schematic vertical sectional view of the lighting device 7 of the seventh embodiment.
The illuminating device 7 is axisymmetric with respect to the optical axis (dashed-dotted line) of the light guide portion, similarly to the illuminating device 1 or the illuminating device 2 described above.

The translucent member 30 of the lighting device 7 is the same as the above-mentioned lighting device 1 or lighting device 2, but has a different shape.

In the example shown in FIG. 10, the shape of the first light reflecting surface 31 can be a rotating surface of a part of the ellipse in the meridional cross section. The shape of the first light transmitting surface 33 is a rotating surface orthogonal to the light rays reflected by the first light reflecting surface 31, and the normal of the rotating surface is reflected by the first light reflecting surface 31. It can be consistent with the light beam. The shape of the second light reflecting surface 42 can be a rotating surface of a parabola. The axes of all rotating bodies and rotating surfaces coincide with the optical axis of the light guide.

In the meridional cross section of the light guide unit 20, the emission end of the light guide unit 20 can be located at one of the focal points of the first light reflecting surface 31 (a part of the ellipse). In the vertical cross section of the light guide section 20, the focal point of the second light reflecting surface 42 can coincide with the other focal point of the first light reflecting surface 31 (a part of the ellipse). In such a configuration, the light rays emitted from the illuminating device 7 can be aligned in parallel.

That is, the optical axis of the light guide unit 20, the plane including the normal with the first light reflecting surface 31, the normal with the second light reflecting surface 42, and the second light reflecting surface 42. The intersection is part of the second conical curve, and the intersection of the plane with the first light reflecting surface 31 is part of the first conical curve. Then, in the plane, the second conic section is a parabola, the first conic section is an ellipse, the light emitting end of the light guide unit 20 is located at one focal point of the ellipse, and the other focal point of the ellipse and the parabola. The focus overlaps.

On a plane including the optical axis of the light guide unit 20 and perpendicularly intersecting the first light reflection surface 31 and the second light reflection surface 42, the side of the first light reflection surface 31 close to the optical axis of the light guide unit 20. After the light beam reflected by the light beam intersects with the light beam reflected on the side far from the optical axis of the light guide portion 20 on the first light reflecting surface 31, the light transmitted through the first light transmitting surface 33 is transmitted to the second light transmitting surface 33. It is incident on the light reflecting surface 42 and reflected.

That is, one of the first light reflecting surfaces 31 in a plane including the optical axis of the light guide unit 20, the normal line having the first light reflecting surface 31, and the normal line having the second light reflecting surface 42. After intersecting the light beam reflected on the end side of the first light reflecting surface 31 and the light ray reflected on the other end side of the first light reflecting surface 31, it is incident on the second light reflecting surface 42 and the second light reflecting surface. It is reflected at 42.

When the intensity distribution of the light emitted from the light guide unit 20 becomes maximum on the optical axis of the light guide unit 20 and decreases monotonically as the distance from the optical axis of the light guide unit 20 increases, the light guide on the first light reflecting surface 31 The light intensity on the side near the optical axis of the unit 20 is strong (the density of the light beam is high), and the light intensity on the side far from the optical axis of the light guide unit 20 on the first light reflecting surface 31 is weak (the density of the light beam is low). ).

The end of the first light reflecting surface 31 on the side close to the light guide unit 20 is provided in a region having a light flux density higher than half the value of the maximum light flux density of the light emitted from the light guide unit 20.

The light rays reflected on the side of the first light reflecting surface 31 near the optical axis of the light guide unit 20 and the light rays reflected on the side of the first light reflecting surface 31 far from the optical axis of the light guide unit 20 By intersecting, the difference in density of the light beam incident on and reflected on the side near the optical axis and the side far from the optical axis of the light guide portion 20 on the second light reflecting surface 42 becomes small. According to such a seventh embodiment, the boundary (bright / dark boundary) between the irradiated area (bright area) and the non-irradiated area (dark area) of the lighting device 7 can be clarified.

According to the seventh embodiment, since the translucent member 30 has the first light reflecting surface 31, glare can be suppressed with a configuration in which the number of parts is reduced. Further, the depth size of the lighting device 7 can be suppressed.

Further, in the seventh embodiment, the size of the irradiation region by the lighting device 7 can be made variable by moving the reflection member 41 having the second light reflection surface 42 in the optical axis direction of the light guide unit 20. .. That is, the distance between the first light reflecting surface 31 and the second light reflecting surface 42 in the optical axis direction of the light emitted from the light guide unit 20 is variable. This is because the light rays emitted from the illuminating device 7 can be aligned in parallel, and can be focused or diverged.

(8th Embodiment)
FIG. 11 shows a schematic vertical sectional view of the lighting device 8 of the eighth embodiment.
The lighting device 8 is axisymmetric with respect to the optical axis (dashed line) of the light guide unit. The lighting device 8 includes a light source, a light guide unit 20, a translucent member 30 that transmits light emitted from the light guide unit 20, and a support 79.

The light guide portion 20 has a columnar core portion 21, a clad portion 22 surrounding the core portion 21, and a covering portion 26 surrounding the clad portion 22. The refractive index of the core portion 21 is higher than that of the clad portion 22. The boundary between the clad portion 22 and the covering portion 26 may have the function of a mirror that reflects the light transmitted through the clad portion 22. This suppresses the temperature rise of the covering portion 26 due to light absorption. The light guide unit 20 is coupled to a connector unit 78 for connecting to a light source.

The light source may include, for example, an optical fiber 80 at the exit end. The optical fiber 80 has a core portion 81, a clad portion 82 surrounding the core portion 81, and a covering portion 86 surrounding the clad portion 82. A ferrule 88 is attached to the end of the optical fiber 80.

The optical fiber 80 and the ferrule 88 are held by the connector portion 89 on the light source side. A spring 87 is provided inside the connector portion 89. The spring 87 presses the ferrule 88 on the light source side against the light guide portion 20 of the lighting device 8.

By coupling the connector portion 89 on the light source side and the connector portion 78 on the lighting device 8 side, the light emitting end portion of the ferrule 88 and the light incident end portion of the light guide portion 20 are optically coupled. The connector portions 89 and 78 facilitate the replacement of the light source.

The light transmitting member 30 is directly joined to, for example, the light guide unit 20 and is provided at the light emitting end of the light guide unit 20. The translucent member 30 is made of a material having a refractive index equal to the average refractive index of the clad portion 22. Alternatively, the translucent member 30 is made of a material having a refractive index equal to the average refractive index of the core portion 21. The contour of the translucent member 30 seen from the light emitting side of the lighting device 8 is, for example, a circle.

The translucent member 30 is held by the support 79. The support 79 is provided integrally with, for example, the connector portion 78.

The translucent member 30 of the lighting device 8 has a first light reflecting surface 31, a second light reflecting surface 32, and a second light transmitting surface 34, similarly to the above-mentioned lighting device 4. A light reflecting film can be provided on the first light reflecting surface 31 and the second light reflecting surface 32.

The second light transmitting surface 34 is orthogonal to the light rays reflected by the second light reflecting surface 32. This facilitates light transmittance control on the second light transmitting surface 34. A low reflection film can be provided on the second light transmitting surface 34.

Further, the lighting device 8 includes a beam expander 95 in a region including the optical axis of the light guide unit 20. In the example shown in FIG. 11, the translucent member 30 has a region on the optical axis of the light guide unit 20 that expands the diameter of a bundle of light rays. A part of the surface of the translucent member 30 (a surface region near and in front of the optical axis of the light guide portion 20) has a lens function (for example, a concave lens 36).

Further, a convex lens 97 is arranged in front of the translucent member 30 with the same axis as the concave lens 36. The convex lens 97 is held by the support 79. The concave lens 36 provided on the translucent member 30 and the convex lens 97 in front of the concave lens 36 constitute the beam expander 95.

The shape of the first light reflecting surface 31 can be a rotating surface of a part of an ellipse in the meridional cross section. The shape of the second light reflecting surface 32 can be a rotating surface of a parabola.

In the vertical cross section of the light guide unit 20, the light emitting end of the light guide unit 20 can be located at one of the focal points of the first light reflecting surface 31 (a part of the ellipse). In the vertical cross section of the light guide section 20, the focal point of the second light reflecting surface 32 can coincide with the other focal point of the first light reflecting surface 31 (a part of the ellipse). In such a configuration, the light rays emitted from the illuminating device 8 can be aligned in parallel.

That is, the optical axis of the light guide unit 20, the plane including the normal with the first light reflecting surface 31, the normal with the second light reflecting surface 32, and the second light reflecting surface 32. The intersection is part of the first conical curve, and the intersection of the plane with the first light reflecting surface 31 is part of the second conical curve. The first conic section is a parabola, the second conic section is an ellipse, the light emitting end of the light guide portion 20 is located at one focal point of the ellipse, and the other focal point of the ellipse and the focal point of the parabola are. Overlap.

On a plane including the optical axis of the light guide unit 20 and perpendicularly intersecting the first light reflection surface 31 and the second light reflection surface 32, the side of the first light reflection surface 31 close to the optical axis of the light guide unit 20. After the light beam reflected by the light beam crosses the light beam reflected on the side far from the optical axis of the light guide unit 20 on the first light reflecting surface 31, the light beam is incident on and reflected on the second light reflecting surface 32.

That is, in a plane including the optical axis of the light guide unit 20, the normal line having the first light reflecting surface 31, and the normal line having the second light reflecting surface 32, one of the first light reflecting surfaces 31. After intersecting the light beam reflected on the end side of the first light reflecting surface 31 and the light ray reflected on the other end side of the first light reflecting surface 31, it is incident on the second light reflecting surface 32 and the second light reflecting surface. It is reflected at 32.

When the intensity distribution of the light emitted from the light guide unit 20 becomes maximum on the optical axis of the light guide unit 20 and decreases monotonically as the distance from the optical axis of the light guide unit 20 increases, the light guide unit on the first light reflecting surface 31 The light intensity on the side near the optical axis of 20 is strong (the density of the light beam is high), and the light intensity on the side far from the optical axis of the light guide portion 20 on the first light reflecting surface 31 is weak (the density of the light beam is low). ..

The end of the first light reflecting surface 31 on the side close to the light guide unit 20 is provided in a region having a light flux density higher than half the value of the maximum light flux density of the light emitted from the light guide unit 20.

The light rays reflected on the side of the first light reflecting surface 31 near the optical axis of the light guide unit 20 and the light rays reflected on the side of the first light reflecting surface 31 far from the optical axis of the light guide unit 20 By intersecting, the difference in density of the light beam incident and reflected on the side near the optical axis and the side far from the optical axis of the light guide portion 20 on the second light reflecting surface 32 becomes small. This clarifies the boundary (bright / dark boundary) between the irradiated area (bright area) and the non-irradiated area (dark area) of the lighting device 8.

Further, according to the eighth embodiment, the beam expander 95 provided in the region including the optical axis of the light guide unit 20 can suppress the darkening of the region near the center of the irradiation region.

As a modification of the eighth embodiment described above, a first light transmitting surface is provided on a part of the surface of the light transmitting member 30, and a second light reflecting surface is provided on a part of the inner surface of the support 79. May be good.

(9th Embodiment)
FIG. 12 shows a schematic vertical sectional view of the lighting device 9 of the ninth embodiment. FIG. 13 is a schematic front view seen from the light emitting side of the lighting device 9.

The lighting device 9 includes a light source (not shown), a housing 151, a light guide unit 23, a light transmitting member 60, and a reflecting member (or a support of a light reflecting film that functions as a second light reflecting surface). It has 141 and. The light guide unit 23, the light transmitting member 60, and the reflecting member 141 are arranged in the housing 151.

The light guide portion 23 has a core portion 24, a clad portion 25 that surrounds the core portion 24 or is sandwiched from above and below along the second direction, and a covering portion 26 that surrounds the clad portion 25. The boundary between the clad portion 25 and the covering portion 26 may have the function of a mirror that reflects the light transmitted through the clad portion 25. This suppresses the temperature rise of the covering portion 26 due to light absorption.

The light guide unit 23 is formed in a plate shape, for example, and the optical axis orthogonal cross-sectional shape of the light guide unit 23 is, for example, a quadrangle.

The light transmitting member 60 includes a first light reflecting surface 61, a first light transmitting surface 63, a third light reflecting surface 65, a fourth light reflecting surface 66, and a fourth light transmitting surface 67. Has. A light reflecting film can be provided on the first light reflecting surface 61, the third light reflecting surface 65, and the fourth light reflecting surface 66. In the ninth embodiment, the translucent member 60 can be composed of a plurality of members having the same refractive index.

The reflecting member 141 includes a light reflecting film, and has a second light reflecting surface 142 to which light reflected by the first light reflecting surface 61 is incident and emits the incident light forward.

The first light transmitting surface 63 is orthogonal to a light ray traveling from the first light reflecting surface 61 to the second light reflecting surface 142. This facilitates light transmittance control on the first light transmitting surface 63. A low reflection film can be provided on the first light transmitting surface 63.

The fourth light transmitting surface 67 is orthogonal to the light rays reflected by the fourth light reflecting surface 66. This facilitates light transmittance control on the fourth light transmitting surface 67. A low reflection film can be provided on the fourth light transmitting surface 67. As shown in FIG. 13, the shape of the fourth light transmitting surface 67 is, for example, a quadrangle.

The third light reflecting surface 65, the fourth light reflecting surface 66, and the fourth light transmitting surface 67 are arranged in front of the first light reflecting surface 61. The light emitted from the light guide unit 23 includes light incident on the first light reflecting surface 61 and light incident on the third light reflecting surface 65.

In the vertical cross section of the light guide unit 23, the light emitting end of the light guide unit 23 can be located at one of the focal points of the first light reflecting surface 61 (a part of the ellipse). In the longitudinal section of the light guide 23, the focal point of the second light reflecting surface 142 can coincide with the other focal point of the first light reflecting surface 61 (part of the ellipse). In the vertical cross section of the light guide unit 23, the light emitting end of the light guide unit 23 can be located at one of the focal points of the third light reflecting surface 65 (a part of the ellipse). In the longitudinal section of the light guide 23, the focal point of the fourth light reflecting surface 66 can coincide with the other focal point of the third light reflecting surface 65 (part of the ellipse). In such a configuration, the light rays emitted from the illuminating device 9 can be aligned in parallel.

The end of the first light reflecting surface 61 on the side close to the light guide unit 23 is provided in a region having a light flux density higher than half the value of the maximum light flux density of the light emitted from the light guide unit 23.

The light rays reflected on the side of the first light reflecting surface 61 near the optical axis of the light guide unit 23 and the light rays reflected on the side of the first light reflecting surface 61 far from the optical axis of the light guide unit 23. By intersecting, the difference in density of the light beam incident on and reflected on the side near the optical axis and the side far from the optical axis of the light guide unit 23 in the second light reflecting surface 142 becomes small.

One end of the third light reflecting surface 65 in a plane including the optical axis of the light guide 23, the normal line having the first light reflecting surface 61, and the normal line having the second light reflecting surface 142. After the light rays reflected on the side intersect with the light rays reflected on the other end side of the third light reflecting surface 65, they are incident on the fourth light reflecting surface 66 and are incident on the fourth light reflecting surface 66. Be reflected.

According to the lighting device 9 of the ninth embodiment as described above, it is possible to prevent the region near the center of the irradiation region from becoming dark.

Further, according to the ninth embodiment, glare can be suppressed and the depth size of the lighting device 9 can be suppressed as in the third embodiment described above.

The lighting devices of the embodiments described above include spotlights, vehicle headlights (automobile headlights), signboard / bulletin board lighting, co-op lighting (indirect lighting that illuminates the ceiling surface), and cornis lighting (on the wall surface). It can be suitably used for indirect lighting that irradiates light) and wall washer lighting.

In addition, medical lighting devices and the like are required not to emit unintended electromagnetic waves (suppression of electromagnetic interference (EMI)). Since the light source for lighting that emits light via the optical fiber can easily move the power supply circuit away from the place where lighting is required, it is easy to suppress the EMI. Therefore, the lighting device of the embodiment can be suitably used for medical lighting such as for surgery and dentistry.

The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. All embodiments that can be implemented by those skilled in the art with appropriate design changes based on the above-described embodiments of the present invention also belong to the scope of the present invention as long as the gist of the present invention is included. In addition, in the scope of the idea of the present invention, those skilled in the art can come up with various modified examples and modified examples, and these modified examples and modified examples also belong to the scope of the present invention.

1 to 9 ... Illumination device 20, 23 ... Light guide unit 30, 60 ... Translucent member 31, 61 ... First light reflecting surface 33, 63 ... First light transmitting surface 32, 42, 62, 142 ... Second Light reflecting surface 34, 64 ... Second light transmitting surface 41, 141 ... Reflecting member 65 ... Third light reflecting surface 66 ... Fourth light reflecting surface 67 ... Fourth light transmitting surface 95 ... Beam expander

Claims (13)

Light source and
A light guide portion having a central portion and a peripheral portion having a refractive index lower than the refractive index of the central portion and guiding light from the light source.
Reflective members and
A translucent member provided at the light emitting end of the light guide portion and transmitting light emitted from the light guide portion.
Equipped with
The translucent member has a first light reflecting surface that reflects light emitted from the light guide portion.
The reflecting member has a second light reflecting surface to which light reflected by the first light reflecting surface is incident and emits the incident light forward .
An intersection of a plane including the optical axis of the light guide unit, a normal having the first light reflecting surface, and a normal having the second light reflecting surface, and the first light reflecting surface. Is part of the first conical curve,
A lighting device characterized in that the line of intersection between the plane and the second light reflecting surface is a part of a second conic section . The lighting device according to claim 1, wherein the light-transmitting member further has a first light-transmitting surface orthogonal to a light ray traveling from the first light-reflecting surface to the second light-reflecting surface. The first conic section is a straight line and the second conic section is part of a parabola.
The illumination according to claim 2 , wherein the distance between the first light reflecting surface and the second light reflecting surface in the optical axis direction of the light emitted from the light guide portion is variable. Device. The first conic section is an ellipse and the second conic section is a parabola.
The illuminating device according to claim 2 , wherein the light emitting end of the light guide portion is located at one focal point of the ellipse, and the other focal point of the ellipse and the focal point of the parabola overlap. In a plane including the optical axis of the light guide portion, the normal having the first light reflecting surface, and the normal having the second light reflecting surface.
After the light beam reflected on one end side of the first light reflecting surface and the light ray reflected on the other end side of the first light reflecting surface intersect, the second light reflecting surface The lighting device according to claim 1 or 2 , wherein the light is incident on the light and is reflected by the second light reflecting surface. A third light reflecting surface and a fourth light reflecting surface are arranged in front of the first light reflecting surface.
The light emitted from the light guide portion includes light incident on the first light reflecting surface and light incident on the third light reflecting surface.
One end of the third light reflecting surface in a plane including the optical axis of the light guide, the normal line having the first light reflecting surface, and the normal line having the second light reflecting surface. After the light beam reflected on the side intersects with the light beam reflected on the other end side of the third light reflecting surface, it enters the fourth light reflecting surface and is incident on the fourth light reflecting surface. The lighting device according to claim 4 or 5 , wherein the light is reflected. Light source and
A light guide unit that guides the light from the light source,
A translucent member provided at the light emitting end of the light guide portion and transmitting light emitted from the light guide portion.
Equipped with
The translucent member has a first light reflecting surface that reflects light emitted from the light guide portion and a second light that is reflected by the first light reflecting surface and emits the incident light forward. It has a light reflecting surface of
A lighting device characterized in that the contour of the translucent member seen from the light emitting side of the lighting device is circular. The lighting device according to claim 7 , wherein the light guide portion has a central portion and a peripheral portion having a refractive index lower than that of the central portion. The illuminating device according to claim 7 , wherein the translucent member further has a second light transmitting surface orthogonal to a light ray reflected by the second light reflecting surface. The lighting device according to any one of claims 7 to 9 , wherein the translucent member further has a region on the optical axis of the light guide portion for expanding the diameter of a bundle of light rays. The light guide portion and the translucent member are joined to each other.
The lighting device according to any one of claims 1 to 10 , wherein the translucent member is made of a material having a refractive index equal to the average refractive index of the central portion of the light guide portion. Claims 1 to 11 are provided in a region where the end of the first light reflecting surface on the side close to the light guide portion is higher than half the value of the maximum luminous flux density of the light emitted from the light guide portion. The lighting device according to any one of the above. The lighting device according to any one of claims 1 to 12 , wherein the numerical aperture of the light guide portion is 0.5 or less.

Images