JP7182153B2 - lighting equipment - Google Patents

Description

The present invention relates to a lighting device having a rod-shaped light guide.

2. Description of the Related Art Conventionally, there has been known a lighting device in which light emitted from a light source enters from the end of a rod-shaped light guide and is emitted from the outer peripheral surface of the light guide (see, for example, Patent Document 1).

JP 2014-199752 A

However, when a light source is arranged at each of the longitudinal ends of a long light guide and the light is made incident on the light guide from both longitudinal ends of the light guide, heat, moisture, or the like causes the light to enter the light guide. There is a problem that the light body expands or shrinks, and the light incident efficiency of the light emitted from the light source into the light guide body is lowered.

The present invention has been made to solve such problems. It is an object of the present invention to provide a lighting fixture capable of suppressing a decrease in the light incidence efficiency of the light.

To solve the above problems, a lighting device according to an aspect of the present invention includes a rod-shaped light guide having a light extraction region on an outer peripheral surface and having at least one end surface serving as a light incident surface; a light source for irradiating light toward the light incident surface of the light guide; Prepare.

ADVANTAGE OF THE INVENTION According to this invention, even if a light guide expands or shrinks, the illuminating device which can maintain the positional relationship of the light source and the edge part of a light guide can be provided.

FIG. 1 is a perspective view of a lighting device according to an embodiment. FIG. 2 is a cross-sectional view of the lighting device according to the embodiment. FIG. 3 is a cross-sectional view of the lighting device according to the embodiment. 4 is a cross-sectional view of a lighting device according to Modification 1. FIG. FIG. 5 is a cross-sectional view of a lighting device according to Modification 2. FIG. FIG. 6 is a cross-sectional view of a lighting device according to Modification 3. As shown in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. All of the embodiments described below represent preferred specific examples of the present invention. Therefore, the numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of the constituent elements, etc. shown in the following embodiments are examples and are not intended to limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in independent claims representing the highest level concept of the present invention will be described as optional constituent elements.

Each figure is a schematic diagram and is not necessarily strictly illustrated. Moreover, in each figure, the same code|symbol is attached|subjected to the substantially same structure, and the overlapping description is abbreviate|omitted or simplified.

A lighting device according to an embodiment of the present invention will be described below.

[Constitution]
First, the configuration of a lighting device according to an embodiment of the present invention will be described. FIG. 1 is a perspective view of a lighting device 10 according to an embodiment. FIG. 2 is a cross-sectional view of lighting device 10 according to the embodiment. FIG. 3 is a cross-sectional view of lighting device 10 according to the embodiment. Specifically, FIG. 2 is a cross-sectional view of a cross-sectional view including the II-II cutting line in FIG. 3, and FIG. 3 is a cross-sectional view of a cross-sectional view including the III-III cutting line in FIG. is. In the present embodiment, lighting device 10 is installed on the ceiling of a building, and illumination light is emitted downward from lighting device 10 as an example. Note that, depending on the installation posture of the illumination device 10, the illumination light emission direction may not be downward.

As shown in FIGS. 1 to 3, the illumination device 10 includes a housing 20, a pair of light sources 30, a light guide 40, and a reflecting member 50. As shown in FIGS. In addition, in FIG. 1, the housing|casing 20 is illustrated with the broken line.

The housing 20 houses a pair of light sources 30 , a light guide 40 and a reflecting member 50 . In addition to these, the housing 20 accommodates a power supply unit (not shown) electrically connected to an external power supply. The power supply section is electrically connected to the pair of light sources 30 and supplies power to each light source 30 . Specifically, the power supply unit includes a control unit, and the control unit controls power supply to each light source 30 to control lighting and extinguishing of each light source 30 . The control unit can also perform dimming and color control of each light source 30 .

The housing 20 is formed in the shape of an elongated box, and a part thereof is translucent. Specifically, the housing 20 has translucency in a portion facing the outer peripheral surface of the light guide 40 . The light emitted from the outer peripheral surface of the light guide 40 passes through the translucent portion of the housing 20 and is emitted to the outside of the housing 20 . In the present embodiment, the case where the portion having translucency in housing 20 is an opening is exemplified, but the portion may be formed of a member having translucency. Examples of translucent members include transparent members, light diffusing members, and lens members.

As shown in FIGS. 2 and 3, the housing 20 is shaped like a rectangular box with an open bottom. Inside the housing 20, a reflective member 50 and a light guide 40 are arranged in this order from the top. As shown in FIG. 2 , the light guide 40 is directly sandwiched between the pair of long side walls 21 of the housing 20 .

Further, as shown in FIG. 3, light sources 30 are fixed to the pair of short side walls 22 of the housing 20, respectively. A pair of light sources 30 are arranged so as to face each end surface of the light guide 40 .

The housing 20 is a support portion that supports the light guide 40 so that the positions of both ends of the light guide 40 are fixed while allowing the light guide 40 to bend due to expansion due to temperature or moisture absorption. is. Specifically, the housing 20 has a pair of light source protection members 25 that sandwich the light guide 40 in the longitudinal direction. Each light source protection member 25 is a member that protects the light source 30 by being interposed between the light guide 40 and the light source 30 . Each of the pair of light source protection members 25 is fixed within the housing 20 at a position spaced apart from each light source 30 by a predetermined distance. Each light incident surface 41 of the light guide 40 is in contact with each of the pair of light source protection members 25 . That is, the pair of light source protection members 25 sandwich the light guide 40 in the longitudinal direction. Each light source protection member 25 has such rigidity that the light source protection member 25 does not deform even if the light guide 40 expands due to temperature or moisture absorption. Therefore, the light source protection member 25 prevents the light guide 40 from contacting the light source 30 and the light source protection member 25 itself from contacting the light source 30 . Thus, the light source protection member 25 protects the light source 30 . Further, since the light guide 40 is sandwiched between the pair of light source protection members 25 , the positions of both ends of the light guide 40 are fixed within the housing 20 .

The pair of light source protection members 25 sandwich the light guide 40 while applying a predetermined compressive force in the axial direction of the light guide 40 to the light guide 40 before expansion due to temperature or moisture absorption. there is The predetermined compressive force may be a compressive force that slightly compresses and deforms the light guide 40 before expansion due to temperature or moisture absorption. Since the light guide 40 is previously compressed and deformed in this manner, the light guide 40 can be smoothly bent when the light guide 40 thermally expands. When bent, the bending of the light guide 40 is guided downward by the pair of long side walls 21 of the housing 20 . As described above, since the housing 20 is open at the bottom, even if the light guide 40 is bent and displaced downward, the bending is not restricted. That is, the housing 20 accommodates the light guide 40 while allowing the light guide 40 to bend.

A through hole 26 is formed in each light source protection member 25 along the optical axis direction of the light source 30 . Thereby, the light from each light source 30 enters each end surface of the light guide 40 through the through hole 26 of each light source protection member 25 . Each end surface of the light guide 40 is hereinafter referred to as a light incident surface 41 .

The light source 30 includes a substrate and a light emitting element. The substrate is a rectangular substrate and is arranged so as to face each light incident surface 41 of the light guide 40 . A light emitting element is mounted on the main surface of the substrate facing the light incident surface 41 of the light guide 40 .

The light emitting element is a so-called SMD (Surface Mount Device) type LED element. The SMD type LED element is specifically a package type LED element in which an LED chip is mounted in a resin-molded cavity and the cavity is filled with a phosphor-containing resin. Note that the light source 30 is not limited to such a configuration, and a COB (Chip On Board) type light source in which an LED chip is directly mounted on a substrate may be used. In addition, the light emitting element of the light source 30 is not limited to an LED element, and may be, for example, a semiconductor light emitting element such as a semiconductor laser, or an EL element such as an organic EL (Electro Luminescence) or an inorganic EL or other solid light emitting element. It may be an element.

The reflecting member 50 is a sheet-like optical member that reflects light leaked from a light extraction region 44 (described later) of the light guide 40 . Specifically, the reflecting member 50 is made of a metal material having light reflectivity, such as aluminum (Al). The reflecting member 50 is arranged so as to overlap the light extraction region 44 of the light guide 40 . The reflecting member 50 reflects the light leaked from the light extraction region 44 of the light guide 40 and causes the light to enter the light guide 40 again.

Next, the light guide 40 will be described in detail. As shown in FIGS. 2 and 3, the light guide 40 is a rod-shaped light guide having a generally uniform outer shape when viewed in the axial direction. Specifically, the light guide 40 is a substantially cylindrical elongated and compact light guide. The light guide 40 is made of translucent resin such as polycarbonate or acrylic resin, but may be made of other translucent materials.

Here, the “substantially columnar shape” is based on a circular outer shape when viewed in the axial direction. In other words, any shape may be used as long as it can be recognized at first glance that a circle is the reference. A substantially cylindrical shape includes not only a circular shape when viewed in the axial direction, but also a shape in which a part of the circle is notched, a shape in which a part of the circle protrudes, or a circular shape with minute irregularities on the outer periphery. Formed shapes shall be included. These shapes may be combined. Also, the circular shape may include an elliptical shape and an oval shape. In the present embodiment, the light guide 40 has a circular shape with a part cut away when viewed in the axial direction.

The light guide 40 has a planar portion 42 partially notched and an arcuate curved surface portion 43 when viewed in the axial direction. The curved surface portion 43 is a curved surface that is smooth as a whole. The light guide 40 is arranged in the housing 20 in such a posture that the flat surface portion 42 faces upward and the curved surface portion 43 faces downward.

A flat portion 42 of the light guide 40 is provided with a light extraction region 44 for reflecting light traveling in the light guide 40 and extracting the light from the curved surface portion 43 to the outside. Therefore, the light extraction region 44 is also flat. Although FIG. 2 illustrates the case where the light extraction region 44 is formed on a portion of the planar portion 42 , the light extraction region 44 may be formed on the entire planar portion 42 . A reflecting member 50 is superimposed on the light extraction region 44 so as to be in contact therewith. Between the planar portion 42 of the light guide 40 and the reflective member 50, an adhesive portion 60 is provided to join the light guide 40 and the reflective member 50 together. The adhesive portion 60 is formed of an adhesive, and is arranged at a location that has a small optical effect on the light guide 40 . Since the light guide 40 and the reflective member 50 are bonded together by the bonding portion 60, even if the light guide 40 is bent, the contact between the light guide 40 and the reflective member 50 is maintained. That is, the bonding portion 60 is a maintaining portion that maintains the contact of the reflecting member 50 with the light extraction region 44 when the light guide 40 is bent.

In the light extraction region 44 , a plurality of recesses 45 that are recessed toward the inside of the light guide 40 are arranged in a matrix. In other words, the light extraction region 44 can also be said to be a region in which a plurality of concave portions 45 are formed.

The concave portion 45 is a point-like prism in plan view. Specific shapes of the concave portion 45 include, for example, a truncated cone shape, a truncated pyramid shape, a cone shape, a pyramid shape, and the like. Note that the concave portion 45 may be an elongated groove-shaped prism. Here, the plurality of recesses 45 included in the light extraction region 44 are formed by laser processing. When the light extraction region 44 is flat, it is easy to focus the laser when forming any of the recesses 45 . Therefore, the plurality of recesses 45 can be processed with high precision.

The light traveling through the light guide 40 is reflected by the inner surfaces of the recesses 45 of the light extraction region 44 toward the curved surface portion 43, and finally emitted downward from the curved surface portion 43 to become illumination light. By the way, part of the light traveling through the light guide 40 is not reflected by the light extraction region 44 but is transmitted therethrough and leaks to the outside. Leaked light from the light extraction region 44 is reflected by the reflecting member 50 and enters the light guide 40 from the flat portion 42 again. The light entering from the light extraction region 44 is emitted downward from the curved surface portion 43 of the light guide 40 to become illumination light.

Further, when the light source 30 is turned on, the light guide 40 expands due to heat transfer from the light source 30, an increase in ambient temperature, moisture absorption, or the like. In FIGS. 2 and 3, the light guide 40 and the reflecting member 50 after being expanded are indicated by a chain double-dashed line L1.

Since the light guide 40 is sandwiched between the pair of light source protection members 25 , the central portion of the light guide 40 moves downward while being guided by the pair of long side walls 21 of the housing 20 due to expansion due to temperature or moisture absorption. and bend. Since the direction of bending is downward, which is the same as the direction in which the illumination light is emitted, the light guide body 40 receives the illumination light from the same position in the width direction (horizontal direction in FIG. 2) even during or after bending. can be emitted. Also, the light guide 40 is not twisted and the output direction is not changed. In other words, the pair of long side walls 21 are guide portions that guide the bending of the light guide 40 toward the direction in which the light from the light guide 40 is emitted.

In addition, since the reflecting member 50 is joined to the light guide 40 by the bonding portion 60 , the reflecting member 50 bends following the bending of the light guide 40 . That is, even if the light guide 40 is bent, the contact state between the reflecting member 50 and the light extraction region 44 of the light guide 40 is maintained. Therefore, even after expansion due to temperature or moisture absorption, the leaked light from the light extraction region 44 can be reliably reflected by the reflecting member 50 to enter the light guide 40 again.

The pair of light source protection members 25 sandwich the light guide 40 to fix the positions of both ends of the light guide 40 in the housing 20 . Thereby, even if the light guide 40 expands due to temperature or moisture absorption, the positional relationship between the pair of light incident surfaces 41 of the light guide 40 and the pair of light sources 30 is maintained.

Here, if the radius of curvature r1 (see FIG. 3) of the light guide 40 in the bent state is five times or more the diameter d1 (see FIG. 2) of the light guide 40 in cross section, then , "curvature radius when the light guide 40 is bent" is the radius of curvature when the light guide 40 expands due to heat transfer from the light source 30 and is bent due to temperature or moisture absorption. The radius of curvature in this state can be estimated at the time of design by performing various experiments or simulations. If the light guide body 40 is sharply curved, light may leak from that part. Leakage light from the body 40 can be suppressed to a substantially negligible amount.

It should be noted that when the light source 30 is turned off, the heat transfer to the light guide 40 ceases, so the light guide 40 shrinks. The light guide 40 also shrinks when the ambient temperature drops. As a result, the bending of the light guide 40 is eliminated and the light guide 40 is restored to its original shape. During restoration, the central portion of the light guide 40 moves upward while being guided by the pair of long side walls 21 of the housing 20 .

[Effects, etc.]
As described above, the illumination device 10 according to the present embodiment includes the rod-shaped light guide 40 having the light extraction region 44 on the outer peripheral surface and having at least one end surface serving as the light incident surface 41; The light guide is supported so that the positions of both ends of the light guide 40 are fixed while allowing the light source 30 to irradiate the light toward the light incident surface 41 of the light guide 40 and the bending of the light guide 40. A housing 20 (supporting portion) is provided.

According to this, the housing 20 allows the light guide 40 to bend due to expansion due to temperature or humidity, and the light guide 40 is fixed in position at both ends of the light guide 40 . support. Therefore, even if the light guide 40 bends due to heat transfer from the light source 30, the positional relationship between the light incident surface 41 of the light guide 40 and the light source 30 can be maintained. Therefore, it is possible to suppress the disturbance of the light distribution characteristics of the illumination light caused by the expansion of the light guide 40 due to temperature or humidity.

In the above-described embodiment, the case where the light guide 40 is bent due to expansion due to temperature or humidity is exemplified. However, even if the light guide 40 bends due to its own weight or due to aged deterioration, the positions of both ends of the light guide 40 are fixed. It is also possible to maintain the positional relationship between the light incident surface 41 of 40 and the light source 30 .

Further, the housing 20 supports the light guide 40 while applying a compressive force along the axial direction of the light guide 40 to the light guide 40 .

According to this, since the light guide 40 is given a predetermined compressive force by the housing 20, it is in a state of being compressed and deformed before expansion due to temperature or humidity. If the light guide 40 is compressed and deformed in advance, the light guide 40 can be smoothly bent when the light guide 40 thermally expands. Conversely, when the light guide body 40 shrinks, part of the pre-applied compressive force is released, the deflection becomes small, and the influence on the light distribution characteristics can be suppressed in the same manner as described above. be.

Further, the housing 20 has a light source protection member 25 that is arranged between the light incident surface 41 of the light guide 40 and the light source 30 and applies a compressive force to the light guide 40 .

For example, a compressive force can be applied to the light guide 40 by bringing the light source 30 into contact with the light incident surface 41 of the light guide 40 . However, in this case, the load also acts on the light source 30, which may damage the light source 30. FIG. As described above, the light source protection member 25 arranged between the light incident surface 41 of the light guide 40 and the light source 30 applies a compressive force to the light guide 40, and thus protects the light source 30. can do.

The lighting device 10 also includes a pair of long side walls 21 ( guide part).

According to this, since the pair of long side walls 21 guide the bending of the light guide body 40 in the direction in which the illumination light is emitted, the light guide body 40 can move in the width direction (horizontal direction in FIG. 2) even during or after the bending. ), the illumination light can be emitted from the same position as before bending. Furthermore, since twisting of the light guide body 40 due to bending can be suppressed, it is possible to avoid a change in the emission direction. Therefore, the illumination light output performance can be maintained before and after bending.

In addition, the lighting device 10 includes the reflecting member 50 arranged so as to overlap with the light extraction region 44 of the light guide 40, and the reflection member 50 with respect to the light extraction region 44 when the light guide 40 is bent. and a bonding portion 60 (maintenance portion) for maintaining contact.

According to this, since the reflecting member 50 is joined to the light guide 40 by the bonding portion 60 , the reflecting member 50 bends following the bending of the light guide 40 . That is, even if the light guide 40 is bent, the contact state between the reflecting member 50 and the light extraction region 44 of the light guide 40 is maintained. Therefore, even after expansion due to temperature or humidity, the leaked light from the light extraction region 44 can be reliably reflected by the reflecting member 50 to enter the light guide 40 again. Therefore, the influence on light distribution and optical efficiency due to expansion of the light guide 40 due to temperature or humidity can be suppressed.

In addition, the light guide 40 has a substantially circular outer shape in a cross-sectional view in the axial direction of the light guide 40, and the radius of curvature r1 when the light guide 40 is bent is is five times or more the diameter d1 in a cross-sectional view.

According to this, if the radius of curvature r1 and the diameter d1 satisfy the above relationship, the bending amount of the light guide 40 in the bent state can be reduced. Therefore, light leakage from the light guide 40 can be suppressed, and the influence on light distribution and optical efficiency caused by expansion or contraction of the light guide 40 due to temperature or humidity can be suppressed.

Each of the pair of end surfaces of the light guide 40 is a light incident surface 41 , and a plurality of light sources 30 are provided so as to correspond to each of the pair of light incident surfaces 41 .

According to this, even when a plurality of light sources 30 are provided so as to correspond to each of the pair of light incident surfaces 41, the housing 20 allows the light guide 40 to flex. The light guide 40 is supported so that the positions of both ends of the light guide 40 are fixed. Therefore, even if the light guide 40 bends, the positional relationship between each of the plurality of light sources 30 and each of the pair of light incident surfaces 41 of the light guide 40 can be maintained. Therefore, it is possible to suppress the disturbance of the light distribution characteristics of the illumination light caused by the expansion or contraction of the light guide 40 due to temperature or humidity.

[Modification 1]
In the above-described embodiment, the adhesive portion 60 made of adhesive was exemplified as the maintaining portion. However, the maintaining portion may maintain the contact of the reflective member with the light extraction region by a method other than adhesion. In Modified Example 1, a case will be described in which a part of the reflective member 50a is fitted into the light guide 40a to maintain the contact of the reflective member with the light extraction region. In the following description, parts that are the same as those in the above-described embodiment are denoted by the same reference numerals, and description thereof may be omitted.

FIG. 4 is a cross-sectional view of a lighting device 10A according to Modification 1. As shown in FIG. Specifically, FIG. 4 is a diagram corresponding to FIG. As shown in FIG. 4, the housing 20a has a pair of long side walls 21a facing each other with a width wider than the diameter of the light guide 40a. Both ends 501 a of the reflecting member 50 a protrude downward between the pair of long side walls 21 a and the light guide 40 . Both end portions 501a of the reflecting member 50a are provided with projections 502a, and the projections 502a are fitted into notches 49a formed on the outer peripheral surface of the light guide 40a. As a result, the reflecting member 50a bends following the bending of the light guide 40a. That is, the protrusion 502a of the reflecting member 50a is an example of a maintaining portion that maintains the contact of the reflecting member 50a with the light extraction region 44. FIG. Note that the notch 49a is preferably arranged at a location with a small optical influence on the light guide 40a.

[Modification 2]
In the above-described embodiment, the adhesive portion 60 made of adhesive was exemplified as the maintaining portion. However, the maintaining portion may maintain the contact of the reflective member with the light extraction region by a method other than adhesion. In Modified Example 2, a case will be described in which the light extraction region 44 slides along the reflection member 50 when the light guide 40 is bent, thereby maintaining the contact of the reflection member with the light extraction region. In the following description, parts that are the same as those in the above-described embodiment are denoted by the same reference numerals, and description thereof may be omitted.

FIG. 5 is a cross-sectional view of a lighting device 10B according to Modification 2. As shown in FIG. Specifically, FIG. 5 is a diagram corresponding to FIG. As shown in FIG. 5 , the housing 20 b has a pair of long side walls 21 b facing each other with a width wider than the diameter of the light guide 40 . A cover member 61b is provided at the lower end of the housing 20b to close the opened portion. The cover member 61b is formed of, for example, a translucent member as described above. The cover member 61b contacts the lower end of the light guide 40 and supports the light guide 40 while being fixed to the housing 20b. Also, the cover member 61b is arranged parallel to the reflecting member 50 . Since the light guide 40 is sandwiched between the cover member 61b and the reflection member 50 in the vertical direction, the deflection of the light guide 40 is along the cover member 61b and the reflection member 50 in the width direction ( Left and right direction). In FIG. 5, the light guide 40 after expansion due to temperature or humidity is indicated by a chain double-dashed line L2. That is, since the light extraction area 44 of the light guide 40 also slides along the reflecting member 50 in the width direction, the contact between the light extraction area 44 and the reflecting member 50 is maintained. In this manner, the cover member 61b is an example of a maintaining portion that maintains the contact of the reflecting member 50 with the light extraction region 44 when the light guide 40 is bent.

As described above, the cover member 61b supports the light guide 40 so that the light extraction region 44 slides along the reflecting member 50 when the light guide 40 is bent.

According to this, when the light guide 40 is bent, the light extraction region 44 slides along the reflection member 50, so that the contact state between the reflection member 50 and the light extraction region 44 of the light guide 40 is maintained. It is Therefore, even after expansion due to temperature or humidity, the leaked light from the light extraction region 44 can be reliably reflected by the reflecting member 50 to enter the light guide 40 again.

Further, since the light extraction region 44 slides along the reflecting member 50, even if the light guide 40 is bent, the light guide 40 does not rotate in a cross-sectional view. Thereby, even if the light guide 40 is bent, the emission direction of the illumination light can be maintained.

[Modification 3]
In the above-described embodiment, the substantially cylindrical long light guide 40 is exemplified. Modification 3 will be described by exemplifying a light guide 40c with both ends bent. In the following description, parts that are the same as those in the above-described embodiment are denoted by the same reference numerals, and description thereof may be omitted.

FIG. 6 is a cross-sectional view of a lighting device 10C according to Modification 3. As shown in FIG. Specifically, FIG. 6 is a diagram corresponding to FIG.

As shown in FIG. 6, a light guide 40c provided in a lighting device 10C according to Modification 3 has a substantially U-shape with both ends bent. Specifically, the light guide 40c includes a first portion 401c and a pair of second portions 402c. The first part 401c is formed in a straight line and arranged so that its lower end faces the opening of the housing 20c. Further, the upper end portion of the first portion 401c is a flat portion 42c, and a light extraction region 44c is formed substantially over the entire length of the flat portion 42c. Also, the reflecting member 50 is arranged on the plane portion 42c so as to overlap the light extraction region 44c.

A pair of second portions 402c extend continuously from both ends of the first portion 401c and are bent in the middle. Specifically, the pair of second portions 402c are partially curved in a convex shape facing outward so that the tip surfaces thereof face upward. As a result, the second portion 402c is more flexible than the first portion 401c in terms of shape.

A pair of light sources 30 are arranged in the housing 20c so as to face the tip surfaces of the pair of second portions 402c. The light from each of the pair of light sources 30 enters the inside of the second portion 402c from the distal end surface of each of the pair of second portions 402c. That is, the tip surface of each of the pair of second portions 402c is the light incident surface 41c.

Further, the housing 20c provided in the illumination device 10C has a recess 29c having a depth such that the pair of light sources 30, the pair of light source protection members 25, and the light guide 40c are arranged in order from the top so that they do not protrude. ing. Each light source protection member 25 is a member that protects the light source 30 by being interposed between the light guide 40 c and the light source 30 . Each of the pair of light source protection members 25 is fixed within the housing 20 at a position spaced apart from each light source 30 by a predetermined distance. Each of the pair of light source protection members 25 is in contact with each light incident surface 41c of the light guide 40c and supports the light guide 40c. As a result, the positions of both ends of the light guide 40c are fixed within the housing 20c. In this state, when the light guide 40c expands due to the heat from the light source 30, the first portion 401c expands in the axial direction. At this time, in the pair of second parts 402c, since stress is concentrated on the bent portions, the bent parts bend so as to absorb the elongation of the first parts 401c (two-dot chain line L3 in FIG. 6). reference). Therefore, even if the light guide 40c bends due to heat transfer from the light source 30, the positional relationship between the light incident surface 41c of the light guide 40c and the light source 30 can be maintained. The radius of curvature of this bent portion is preferably five times or more the diameter of the light guide 40c in a cross-sectional view. Specifically, it is preferable that the radius of curvature of the inner peripheral portion of the bent portion is five times or more the diameter of the light guide 40c in a cross-sectional view.

Here, the pair of long side walls 21c of the housing 20c directly sandwich the light guide 40c, and the deflection of the pair of second portions 402c of the light guide 40c is controlled in a predetermined direction (parallel to the plane of FIG. 6). direction).

As described above, the light guide 40c includes a linear first portion 401c having a light extraction region 44c, and a second portion 402c continuous from one end of the first portion 401c and having a tip surface forming the light incident surface 41c. and at least a portion of the second portion 402c is curved.

According to this, in the light guide 40c, since at least a portion of the second portion 402c continuous with the first portion 401c is bent, the bent portion of the second portion 402c is bent when expanded due to temperature or humidity. , the linearity of the first portion 401c can be maintained. Therefore, the light extraction region 44c of the first portion 401c is less likely to deform, and the disturbance of the light distribution characteristics of the illumination light caused by the expansion of the light guide 40c due to temperature or humidity can be further suppressed.

Note that Modified Example 3 exemplifies the case where the first portion 401c and the pair of second portions 402c are integrally molded as a whole. However, an integrated light guide may be formed by joining the first part and the pair of second parts, which are originally separate bodies. In this case, it is possible to form the first portion and the pair of second portions from different materials. Therefore, from the viewpoint of material, it is possible to form the second portion more flexibly than the first portion.

Moreover, although the substantially U-shaped light guide 40c is illustrated in the modification 3, a substantially L-shaped light guide may be used. In this case, one second portion is provided for one light guide.

[others]
As described above, the illumination device according to the present invention has been described based on the above-described embodiment and each modified example, but the present invention is not limited to the above-described embodiment and each modified example.

For example, in the above embodiment, the shape of the light guide 40 in the axial direction is substantially circular, but each light guide may have any shape in the axial direction. Other shapes include an elliptical shape, an oval shape, a polygonal shape, and the like. By adjusting the axial view shape of the light guide 40, it is possible to obtain illumination light with a desired light distribution.

Moreover, in the above embodiment, the case where the light extraction region 44 is flat is exemplified. However, the light extraction area may be curved.

Further, although the light source 30 is provided for each end surface of the light guide 40 in the above embodiment, the light source may be provided for only one end surface of the light guide. Also, a plurality of light sources may be arranged for each end face of the light guide.

Further, in the above-described embodiment, the case where the housing 20 supports the light guide 40 while applying a predetermined compressive force in the axial direction of the light guide 40 is exemplified. However, as long as the positions of both ends of the light guide are fixed, the housing does not have to apply a compressive force to the light guide.

In addition, it can be realized by applying various modifications to each embodiment that a person skilled in the art can think of, or by arbitrarily combining the constituent elements and functions of each embodiment without departing from the spirit of the present invention. Forms are also included in the present invention.

10, 10A, 10B, 10C lighting devices 20, 20a, 20b, 20c housing (supporting portion)
21 long side wall (guide part)
25 light source protection member 30 light sources 40, 40a, 40b, 40c light guides 41, 41b, 41c light incidence surfaces 44, 44b, 44c light extraction area 50 reflection member 60 adhesion part (maintenance part)
61a cover member (maintenance part)
401c first part 402c second part 502a projection (maintenance part)
d1 diameter r1 radius of curvature

Claims (8)

a rod-shaped light guide having a light extraction area on its outer peripheral surface and having at least one end surface as a light incident surface;
a light source that irradiates light toward the light incident surface of the light guide;
a supporting portion that supports the light guide so that the positions of both ends of the light guide are fixed while allowing the light guide to flex;
a wall-shaped guide portion that guides the bending of the light guide in a direction in which light is emitted from the light guide when the light guide is bent ;
At least part of the guide portion is in contact with the light guide before the light guide is bent . The lighting device according to claim 1, wherein the supporting portion supports the light guide while applying a compressive force along the axial direction of the light guide to the light guide. The lighting device according to claim 2, wherein the supporting portion includes a light source protection member that is arranged between the light incident surface of the light guide and the light source and that applies the compressive force to the light guide. . a reflecting member arranged so as to overlap the light extraction region of the light guide;
The lighting device according to any one of claims 1 to 3, further comprising a maintaining portion that maintains contact of the reflecting member with the light extraction region when the light guide is bent. The lighting device according to claim 4, wherein the maintaining section supports the light guide such that the light extraction region slides along the reflecting member when the light guide is bent. The light guide includes a linear first portion having the light extraction region, and a second portion continuous from one end of the first portion and having a tip surface forming the light incident surface,
The lighting device according to any one of claims 1 to 5, wherein at least part of the second portion is curved. The light guide has a substantially circular outer shape in a cross-sectional view in the axial direction of the light guide,
The lighting device according to any one of claims 1 to 6, wherein the radius of curvature of the light guide in a bent state is five times or more the diameter of the light guide when viewed in cross section. each of the pair of end surfaces of the light guide is the light incident surface;
The lighting device according to any one of claims 1 to 7, wherein a plurality of the light sources are provided so as to correspond to each of the pair of light incident surfaces.

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