JP2017079177A - Luminaire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a luminaire capable of effectively making light emitted from a light source incident on a transparent material while holding the transparent material.SOLUTION: An optical member 3 used for a luminaire includes: a convex lens part 31 located between a light source 2 and an edge face 10 of a transparent material 1; a total reflection lens part 33 protruding from the convex lens part 31 toward the peripheral side of the light source 2; and a cylindrical guide lens part 32 surrounding a peripheral surface 11 of the transparent material 1. The convex lens part 31 includes: a surface 31a confronting the edge face 10 of the transparent material 1; and a light focus surface 31b curved in a convex shape toward the light source 2 and having a diameter smaller than that of the surface 31a. An outer peripheral surface 33b of the total reflection lens part 33 is an elliptic arc surface which is a part of an ellipsoid of revolution K. The light source 2 is positioned at one focal point of two focal points of the ellipsoid of revolution K and the other is positioned within the transparent material 1. A diameter D of an outer peripheral surface 32b of the guide lens part 32 and a minor axial length Y the ellipsoid of revolution K have a relationship of D≥Y.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an illumination device including a lens that makes light from a light source incident on a light guide.

  2. Description of the Related Art Some vehicle lighting devices include a long light guide and a light source that makes light incident on the light guide. When light from a light source is incident from the end face of the light guide, light is emitted by leaking part of the light while guiding light in the longitudinal direction.

  Here, in order for the light guide to emit light brightly, it is desired that light be efficiently incident on the light guide.

  For example, Patent Document 1 discloses an optical member having a convex lens portion disposed between a light source and a light guide and a cylindrical guide portion surrounding the peripheral surface of the light guide. Since the convex lens portion has a condensing surface that curves in a convex shape toward the light source, the light emitted from the light source is collected at the convex lens portion and incident on the end surface of the light guide.

  However, in Patent Document 1, light emitted from the side portion of the light source is emitted to the outside and is not incident on the light guide. For this reason, it cannot be said that the light emitted from the light source is effectively used.

  Therefore, Patent Document 2 proposes an optical member in which a total reflection lens portion is provided on a side portion of a light source in addition to a convex lens portion.

Patent No. 4097927 Japanese Patent No. 5152577

  However, the optical member disclosed in Patent Document 2 does not have a structure for holding the light guide, and the light guide is held by a holding member different from the lens.

  Then, this inventor considered adding the guide part of patent document 1 to the optical member provided with the convex lens part and total reflection lens part of patent document 2. FIG. However, if a guide part is simply added to the optical member, light incident from the light source is scattered by the guide part, and light cannot be efficiently incident on the light guide.

  This invention is made | formed in view of this situation, and it aims at providing the illuminating device which can make the light emitted from the light source efficiently inject into a light guide while holding a light guide. .

The lighting device of the present invention is a lighting device including a light source, a light guide, and an optical member disposed between the light source and the light guide,
The optical member includes a convex lens portion positioned between the light source and an end surface of the light guide, a total reflection lens portion protruding from the convex lens portion toward the periphery of the light source, and a periphery of the light guide. A guide lens portion for holding the surface,
The convex lens portion has an exit surface facing the end face of the light guide, and a condensing surface curved in a convex shape toward the light source and having a diameter smaller than the diameter of the exit surface,
The outer peripheral surface of the total reflection lens part is an elliptical arc surface forming a part of a spheroid, and the light source is located at one of the two focal points of the spheroid, and the other is in the light guide. Located in the
When the diameter of the outer peripheral surface of the guide lens portion is D and the short axis length of the spheroid is Y, there is a relationship of D ≧ Y.

  According to the present invention, the optical member is disposed between the light source and the light guide, the end surface of the light guide is held by the exit surface of the convex lens portion of the optical member, and the light is guided by the inner peripheral surface of the guide lens portion. Holds the circumference of the body. For this reason, a light guide can be stably hold | maintained with an optical member.

  Moreover, the diameter of the condensing surface of the convex lens portion is smaller than the diameter of the exit surface. For this reason, the light incident on the condensing surface can be efficiently incident on the end surface of the light guide from the exit surface.

  The outer peripheral surface of the total reflection lens portion is an elliptical arc surface that forms a part of a spheroid. The light source is located at one of the two focal points of the spheroid. Since the light source is located at one focal point of the spheroid, light emitted mainly from the side of the light source out of the light emitted from the light source is incident on the total reflection lens unit, and the total reflection lens unit It is reflected by the outer peripheral surface of. The reflected light is incident on the light guide through the convex lens portion or the guide lens portion from the end surface or the peripheral surface as the incident surface of the light guide.

  The other focal point of the spheroid is located in the light guide. Most of the light emitted from the light source and reflected by the total reflection lens portion has a small incident angle (an angle with respect to the normal of the incident surface) incident on the light guide. When this incident angle is small, the angle of light toward the peripheral surface of the light guide (the angle with respect to the normal of the peripheral surface of the light guide) increases. In the light guide, the angle of light toward the peripheral surface is equal to or greater than the critical angle. For this reason, it becomes difficult for light to leak from the peripheral surface of the light guide, and the inside of the light guide can be guided further. Note that the critical angle is the smallest incident angle at which total reflection occurs when light is incident on a sparse medium (substance having a low refractive index) from an optically dense medium (substance having a high refractive index).

  When the other focal point of the spheroid is closer to the light source than the light guide, that is, between the light source and the light guide (for example, a convex lens portion), the light incident on the light guide The incident angle of the light increases, and the angle of light toward the peripheral surface of the light guide decreases. The angle of light toward the peripheral surface of the light guide is less than the critical angle. The amount of light leaking from the peripheral surface of the angle light guide increases, and the light guide cannot be guided far away.

  Further, when the diameter of the outer peripheral surface of the guide lens portion is D and the minor axis length of the spheroid is Y, there is a relationship of D ≧ Y. In this case, light that is not incident on the total reflection lens unit but is incident on the outside of the convex lens unit, in particular, near the boundary between the condensing surface of the convex lens unit and the inner peripheral surface of the total reflection lens unit. Light enters the guide lens section. The light that has entered the guide lens unit is reflected by the outer peripheral surface of the guide lens unit, and enters the light guide from the peripheral surface. For this reason, according to the optical member of this invention, the light emitted from the light source can be efficiently incident on the light guide.

  As described above, according to the present invention, it is possible to provide an illuminating device that can hold a light guide and can efficiently cause light emitted from a light source to enter the light guide.

It is AA arrow sectional drawing of FIG. 3 for showing the illuminating device of embodiment of this invention. It is an expanded sectional view around the light source of the optical member of this embodiment. It is a top view of the optical member of this embodiment. It is sectional drawing of the optical member for showing the dimensional relationship of this embodiment. It is a section explanatory view of an optical member for showing a course of light of this embodiment. It is explanatory drawing of the course of light when the focus of a spheroid of this embodiment is located in a light guide. Explanatory drawing of the path | route of light when the focus of a spheroid of a reference form is located in the area | region closer to a light source than a light guide. It is explanatory drawing for showing the course of light when the diameter of the outer peripheral surface of a guide lens part of this reference form is shorter than the short-axis length of a spheroid. It is sectional explanatory drawing of the illuminating device at the time of changing the major axis length of a spheroid of this embodiment.

  An illumination device according to an embodiment of the present invention will be described in detail with reference to the drawings.

  The illuminating device of this embodiment is an illuminating device such as a DRL (daytime lighting) or a turn lamp provided together with a vehicle headlamp. As shown in FIG. 1, the lighting device includes a light guide 1, a light source 2, and an optical member 3 disposed between the light source 2 and the light guide 1.

  The light guide 1 uses a cylindrical light guide rod. The light guide 1 should just be a transparent material, for example, uses glass and resin. Examples of the resin used for the light guide 1 include polycarbonate and acrylic. A light source 2 and an optical member 3 are respectively disposed at both ends of the light guide 1 in the longitudinal direction, and the entire light guide emits light.

  Examples of the light source 2 include an LED and a light emitting diode, and an LED is preferable. Among LEDs, CSP (chip size package) -LED is preferable. In the present embodiment, a CSP-LED having a length of 2.0 mm × width of 1.6 mm × thickness of 0.8 mm is used. The light source 2 is joined to the wiring pattern 22 on the substrate 21 by soldering. On the upper surface of the light source 2, a square light emitting surface 20 of □ 0.6 mm is provided.

  The optical member 3 should just be a transparent material, for example, uses resin and glass. Examples of the resin used for the light guide 1 include polymethyl methacrylate, polycarbonate, cyclic polyolefin, and acrylic.

  When the material used for the optical member 3 is a resin, the resin preferably has a higher melting point than the resin used for the light guide 1. When the light guide 1 is made of acrylic, the resin used for the optical member 3 is preferably polycarbonate. Damage to the light guide due to heat can be suppressed by heat insulation of the optical member.

  The optical member 3 includes a convex lens part 31, a guide lens part 32, and a total reflection lens part 33. As shown in FIG. 2, the convex lens portion 31 is located between the light source 2 and the end face 10 of the light guide 1. The convex lens portion 31 has an emission surface 31 a that faces the end surface 10 of the light guide 1 and a condensing surface 31 b that curves convexly toward the light source 2. The diameter b of the condensing surface 31b is smaller than the diameter a of the exit surface 31a.

  As shown in FIGS. 1 and 3, the guide lens unit 32 is located on the opposite side of the total reflection lens unit 33 with the convex lens unit 31 interposed therebetween. The guide lens unit 32 is cylindrical. The guide lens portion 32 has ribs 32c projecting radially outward from the outer peripheral surface 32b to reinforce the guide lens portion 32.

  As shown in FIGS. 3 and 4, the light guide housing space 34 is partitioned by the inner peripheral surface 32 a of the guide lens portion 32 and the emission surface 31 a of the convex lens portion 31. The light guide 1 is disposed in the light guide housing space 34. The light guide 1 has its end face 10 in contact with the emission surface 31 a of the convex lens portion 31. An inner peripheral surface 32 a of the guide lens portion 32 faces the peripheral surface 11 of the light guide 1. The inner peripheral surface 32a includes a cylindrical portion 32e and holding portions 32d that are positioned slightly radially inward of the cylindrical portion 32e at three locations in the circumferential direction. The light guide 1 is held by the optical member 3 by bringing the peripheral surface 11 of the light guide 1 into contact with the holding portion 32d. The light guide 1 is positioned with respect to the optical member 3 so that the center axis L of the light guide 1 coincides with the center axis L ′ of the light guide housing space 34.

  As shown in FIG. 2, the light source 2 is disposed in the light source space 35 surrounded by the total reflection lens portion 33 and the convex lens portion 31. The total reflection lens portion 33 protrudes in a ring shape toward the periphery of the light source 2 of the convex lens portion 31. The total reflection lens portion 33 has an inner peripheral surface 33a and an outer peripheral surface 33b. The inner peripheral surface 33 a extends in parallel with the central axis L of the optical member 3. The outer peripheral surface 33 b approaches the inner peripheral surface 33 a toward the tip of the total reflection lens portion 33.

  As shown in FIG. 4, the outer peripheral surface 33 b of the total reflection lens portion 33 is an elliptical arc surface that forms a part of the spheroid K. The ratio (X / Y) of the major axis length X to the minor axis length Y of the spheroid K is 2.0.

  The spheroid K has two focal points G1 and G2. The light emitting surface 20 of the light source 2 is located at one of the two focal points G1 and G2, and the other focal point G2 is located at a portion surrounded by the guide lens portion 32 in the light guide 1. .

  There is a relationship of D ≧ Y between the diameter D of the light guide housing space 34 of the guide lens portion 32 and the minor axis length Y of the spheroid K. The short axis Ky of the spheroid K is located farther from the light source 2 than the exit surface 31 a of the convex lens portion 31. The outer peripheral surface 32 b of the guide lens portion 32 intersects with a virtual straight line R connecting the light source 2 and the boundary portion S between the condensing surface 31 b of the convex lens portion 31 and the inner peripheral surface 33 a of the total reflection lens portion 33. Is arranged.

  Moreover, as shown in FIG. 2, the shortest distance f between the light emission surface 20 of the light source 2 and the condensing surface 31b of the convex lens part 31 is 0.5-1.2 mm. When the shortest distance f is less than 0.5 mm, the condensing surface 31b is too close to the light source 2, and the convex lens part 31 may be heated and melted by the light source 2. If the shortest distance f exceeds 1.2 mm, the amount of light incident on the condensing surface 31b may be reduced. In this embodiment, the shortest distance f between the light emitting surface 20 of the light source 2 and the condensing surface 31b of the convex lens part 31 shall be 0.8 mm.

  The diameter “a” of the exit surface 31 a of the convex lens portion 31 may be substantially the same as the diameter of the light guide 1. Both the diameter a of the exit surface 31a of the convex lens part 31 and the diameter of the light guide 1 are preferably 2.0 to 5.0 mm. In the present embodiment, the diameter a of the exit surface 31a of the convex lens portion 31 and the diameter of the light guide 1 are both 3.6 mm.

  The diameter b of the condensing surface 31 b is set larger than the diameter of the light emitting surface 20 of the light source 2. The diameter b of the condensing surface 31b of the convex lens part 31 is smaller than the diameter a of the output surface 31a. The ratio (a / b) of the diameter a of the exit surface 31a to the diameter b of the condensing surface 31b is preferably greater than 1.0 and 2.0 or less, and more preferably 1.1 to 1.7. When the ratio (a / b) is 1 or less, part of the light incident on the condensing surface 31b travels around the exit surface 31a, and the amount of light leaking to the outside of the optical member 3 increases. When the ratio (a / b) exceeds 2.0, when the exit surface 31a is constant, the condensing surface 31b may be small and the amount of light incident from the condensing surface 31b may be reduced. . In this embodiment, the diameter b of the condensing surface 31b is 2.4 mm, and the ratio (a / b) of the diameter a of the exit surface 31a to the diameter b of the condensing surface 31b is 1.5.

  As shown in FIG. 4, the distance c from the exit surface 31a to the tip of the total reflection lens portion 33 is preferably 2.4 to 3.0 mm. In the present embodiment, the distance c from the exit surface 31a to the tip of the total reflection lens portion 33 is 2.8 mm.

  The distance d from the focal point G1 of the spheroid K to the lower end of the spheroid K is preferably 0.5 to 1.2 mm. When the distance d is excessive, the amount of light incident on the light guide 1 out of the light emitted from the light source 2 may be reduced. In the present embodiment, the distance d from the focal point G1 of the spheroid K to the lower end of the spheroid K is 0.8 mm.

  The distance e between the focal points G1 and G2 of the spheroid K is preferably 3.0 to 15.0 mm. When the distance e is too short, the angle γ of the light traveling toward the outer peripheral surface 33b of the total reflection lens portion 33 becomes small, the angle γ becomes less than the critical angle, and leaks outside without being totally reflected by the outer peripheral surface 33b. There is a risk of it. The amount of light incident on the light guide 1 may be reduced. When the distance e is too small, even if light enters the light guide 1, the angle β of the light incident on the light guide 1 toward the peripheral surface 11 becomes small and becomes less than the critical angle. The amount of light leaking from the peripheral surface 11 of the body 1 may increase. For this reason, there is a possibility that the light guide 1 cannot be guided far away. In this embodiment, the distance e between the focal points G1 and G2 of the spheroid K is 6.0 mm.

  In the illuminating device of the present embodiment, as shown in FIG. 5, among the light emitted from the light emitting surface 20 of the light source 2, the light emitted toward the convex lens portion 31 side enters the convex lens portion 31 through the condensing surface 31 b. Is done. The condensing surface 31b converts light into parallel light substantially parallel to the central axis L. The parallel light passes through the convex lens portion 31 and enters the light guide 1 from the end face 10 of the light guide 1 through the emission surface 31a. Here, the diameter b of the condensing surface 31b of the convex lens part 31 is smaller than the diameter a of the output surface 31a. For this reason, the light incident on the condensing surface 31b can be efficiently incident on the end surface 10 of the light guide 1 from the exit surface 31a.

  Of the light emitted from the light emitting surface 20 of the light source 2, the light emitted toward the total reflection lens unit 33 is incident on the total reflection lens unit 33 through the inner peripheral surface 33a. The outer peripheral surface 33b of the total reflection lens portion 33 is an elliptical arc surface, and the light source 2 is located at one focal point G1 of the spheroid K. For this reason, light emitted mainly from the side of the light source 2 out of the light emitted from the light source 2 is incident on the total reflection lens unit 33 and reflected by the outer peripheral surface 33 b of the total reflection lens unit 33. The reflected light is incident on the end surface 10 of the light guide 1 mainly from the emission surface 31a. A part of the light reflected by the outer peripheral surface 33 b of the total reflection lens part 33 enters the light guide 1 from the peripheral surface 11 of the light guide 1 through the guide lens part 32.

  As shown in FIG. 6, the outer peripheral surface 33 b of the total reflection lens portion 33 is an elliptical arc surface that forms a part of a spheroid K having a focal point G <b> 2 in the light guide 1. For this reason, the light incident from the light source 2 and reflected by the outer peripheral surface 33 b of the total reflection lens portion 33 has a small incident angle α incident on the light guide 1. The angle β of light traveling toward the peripheral surface 11 of the light guide 1 may increase and exceed the critical angle. Therefore, the amount of light leaking from the peripheral surface 11 of the light guide 1 is reduced, and the inside of the light guide 1 can be guided further.

  Further, as shown in FIGS. 5 and 6, the light reflected by the outer peripheral surface 33 b of the total reflection lens portion 33 and incident on the light guide 1 is a focal point G <b> 2 of the spheroid K in the light guide 1. Concentrate in the vicinity. Since the focal point G2 is located in a portion surrounded by the guide lens portion 32 in the light guide 1, the light guide 1 is not curved or deformed near the focal point G2. For this reason, the condensed light can be efficiently guided far away. In the present embodiment, not only the focal point G2 of the spheroid K but also the tip of the spheroid K is located in the portion surrounded by the guide lens portion 32 in the light guide 1. The condensed light can be guided to a far place more efficiently.

  On the other hand, as shown in FIG. 7, the other focal point G2 of the spheroid K is closer to the light source 2 than the light guide 1, that is, between the light source 2 and the light guide 1 (for example, a convex lens portion). 31), even if light is incident on the light guide 1, the angle β of the light toward the peripheral surface 11 of the light guide 1 becomes less than the critical angle, and the peripheral surface of the light guide 1 The amount of light leaking from 11 increases. For this reason, the inside of the light guide 1 cannot be guided far away.

  Furthermore, in the present embodiment, as shown in FIG. 4, the short axis Ky of the spheroid K is located farther from the light source 2 than the emission surface 31 a of the convex lens portion 31. That is, the short axis Ky of the spheroid K is located between the focal point G <b> 2 in the light guide 1 and the end face 10 of the light guide 1. For this reason, in the total reflection lens part 33, the area | region which the light of the light source 2 hits and functions as a total reflection lens increases, and the light quantity which can be reflected in the light guide 1 side by the total reflection lens part 33 can be increased. In addition, it is possible to reliably obtain an effect of guiding the spheroid K farther away from the focal point G2 of the spheroid K.

  Further, as shown in FIG. 4, the diameter D of the outer peripheral surface 32 b of the guide lens portion 32 is larger than the short axis length Y of the spheroid K. Of the light emitted from the light emitting surface 20 of the light source 2, the light that does not enter the total reflection lens unit 33 and leaks to the guide lens unit 32 side, particularly the boundary S between the convex lens unit 31 and the total reflection lens unit 33. Light incident on the vicinity enters the guide lens unit 32. The light that has entered the guide lens portion 32 is reflected by the outer peripheral surface 32 b of the guide lens portion 32 and enters the light guide 1 from the peripheral surface 11 of the light guide 1.

  Further, the outer peripheral surface 32 b of the guide lens portion 32 is a virtual connecting the center of the light emitting surface 20 of the light source 2 and the boundary portion S between the condensing surface 31 b of the convex lens portion 31 and the inner peripheral surface 33 a of the total reflection lens portion 33. It is arranged at a position intersecting the straight line R. The outer peripheral surface 32b of the guide lens part 32 is located outside the position W (one-dot chain line in FIG. 4) intersecting the virtual straight line R at the lower end. For this reason, the light incident near the boundary portion S between the convex lens portion 31 and the total reflection lens portion 33 surely enters the guide lens portion 32, and is reflected by the outer peripheral surface 32 b of the guide lens portion 32, thereby guiding the light guide 1. It is reliably incident on the light guide 1 from the peripheral surface 11.

  On the other hand, as shown in FIG. 8, when the diameter D of the outer peripheral surface 32 b of the guide lens part 32 is smaller than the short axis length Y of the spheroid K, the convex lens part 31 and the total reflection lens part 33 The light incident near the boundary S is reflected on the upper surface of the plate-shaped portion 37 outside the guide lens portion 32 and is not incident on the guide lens portion 32. For this reason, the utilization efficiency of light will fall.

  Here, as shown in FIG. 9, the minor axis length Y of the spheroid K is fixed to 5.9 mm, the major axis length X is varied, and the major axis length X and minor axis length Y are changed. The ratio (X / Y) was changed to n1 = 1.3, n2 = 1.6, n3 = 1.8, n4 = 2, n5 = 2.1, and n6 = 2.3. In the case of n2 to n5 (ratio (X / Y) = 1.6 to 2.1), the light reflected by the total reflection lens unit 33 is reduced in the incident angle α incident on the light guide 1. In this state, the angle β incident on the light guide 1 and directed toward the peripheral surface 11 of the light guide 1 is increased, and is equal to or greater than the critical angle. For this reason, light could be guided far away in the light guide 1. Moreover, the total reflection lens part 33 became a shape suitable for shaping | molding, and the moldability improved.

  On the other hand, when n1 = 1.3, the angle γ of the light incident on the total reflection lens portion 33 toward the outer peripheral surface 33b (angle with respect to the normal of the outer peripheral surface of the light) is less than the critical angle, and the outer peripheral surface 33b. In some cases, it was leaked outside without being totally reflected (FIG. 7). Further, the thickness in the radial direction of the total reflection lens portion 33 is increased, and the moldability may be reduced.

  In the case of n6 = 2.3, the tip of the total reflection lens portion 33 is tapered, and the moldability of the total reflection lens portion 33 may be lowered. If the inner peripheral surface 33 a of the total reflection lens unit 33 is brought close to the light emitting surface 20 of the light source 2, the tip of the total reflection lens unit 33 can be made thicker. The tip of the portion 33 may be heated and melted.

  As described above, according to the optical member 3 of the present embodiment, the light emitted from the light source 2 is efficiently incident on the light guide 1.

  The illuminating device of the present embodiment is suitably used for a vehicle headlamp, a headlamp, a marker lamp, a tread on a leg hanging part of a vehicle body, a vehicle interior display system, a decorative lamp, and the like. The lighting device of the present embodiment can be used for home and office lighting devices, fluorescent toys, room lights and the like in addition to vehicles.

(1) The illuminating device of this embodiment is an illuminating device provided with the light source 2, the light guide 1, and the optical member 3 arrange | positioned between the light source 2 and the light guide 1,
The optical member 3 includes a convex lens part 31 positioned between the light source 2 and the end face 10 of the light guide 1, a total reflection lens part 33 protruding from the convex lens part 31 toward the periphery of the light source 2, and a light guide. A guide lens portion 32 that holds one peripheral surface 11,
The convex lens portion 31 has an emission surface 31a facing the end surface 10 of the light guide 1 and a light collection surface 31b that is convex toward the light source 2 and has a diameter smaller than the diameter of the emission surface 31a. ,
The outer peripheral surface 33b of the total reflection lens portion 33 is an elliptical arc surface that forms a part of the spheroid K, and one of the two focal points G1 of the spheroid K is located at the light source 2 and the other focal point. G2 is located in the light guide 1,
When the diameter of the outer peripheral surface 32b of the guide lens portion 32 is D and the short axis length of the spheroid K is Y, there is a relationship of Y ≧ D.

  According to the present embodiment, the optical member 3 is disposed between the light source 2 and the light guide 1, the end surface 10 of the light guide 1 is held by the exit surface 31 a of the convex lens portion 31 of the optical member 3, and the guide The peripheral surface 11 of the light guide 1 is held by the inner peripheral surface 32 a of the lens portion 32. For this reason, the light guide 1 can be stably held by the optical member 3.

  Moreover, the diameter b of the condensing surface 31b of the convex lens part 31 is smaller than the diameter a of the output surface 31a. For this reason, the light incident on the condensing surface 31b can be efficiently incident on the end surface 10 of the light guide 1 from the exit surface 31a.

  The outer peripheral surface 33 b of the total reflection lens portion 33 is an elliptic arc surface that forms a part of the spheroid K. The light source 2 is located in one of the two focal points G1 and G2 of the spheroid K. Since the light source 2 is located at one focal point G 1 of the spheroid K, light emitted mainly from the side of the light source 2 out of the light emitted from the light source 2 is incident on the total reflection lens unit 33. Then, it is reflected by the outer peripheral surface 33 b of the total reflection lens portion 33. The reflected light is incident on the light guide 1 through the convex lens portion 31 or the guide lens portion 32 from the end surface 10 or the peripheral surface 11 as the incident surface of the light guide 1.

  Further, the other focal point G <b> 2 of the spheroid K is located in the light guide 1. Most of the light emitted from the light source 2 and reflected by the total reflection lens unit 33 has a small incident angle α (an angle with respect to the normal of the incident surface) incident on the light guide 1. When the incident angle α of light is small, the angle β of light toward the peripheral surface 11 of the light guide 1 (angle with respect to the normal line of the peripheral surface 11 of the light guide 1) increases. In the light guide 1, the angle β of light toward the peripheral surface 11 is equal to or greater than the critical angle. For this reason, it becomes difficult for light to leak from the peripheral surface 11 of the light guide 1, and the inside of the light guide 1 can be guided further. Note that the critical angle is the smallest incident angle at which total reflection occurs when light is incident on a sparse medium (substance having a low refractive index) from an optically dense medium (substance having a high refractive index).

  When the other focal point G2 of the spheroid K is located closer to the light source 2 than the light guide 1, that is, between the light source 2 and the light guide 1 (for example, the convex lens portion 31), In some cases, the incident angle α of light incident on the light body 1 is increased, and the angle β toward the peripheral surface 11 of the light guide 1 is decreased to be less than the critical angle. The amount of light leaking from the peripheral surface 11 of the light guide 1 increases, and the light guide 1 cannot be guided far away.

  Further, when the diameter of the outer peripheral surface 32b of the guide lens portion 32 is D and the minor axis length of the spheroid K is Y, there is a relationship of D ≧ Y. In this case, light that has not entered the total reflection lens unit 33 and has leaked outside the convex lens unit 31, particularly the inner peripheral surface 33 a of the total reflection lens unit 33 and the condensing surface 31 b of the convex lens unit 31. Light incident near the boundary portion S enters the guide lens portion 32. The light that has entered the guide lens portion 32 is reflected by the outer peripheral surface 32 b of the guide lens portion 32 and enters the light guide 1 from the peripheral surface 11. For this reason, according to the optical member 3 of this embodiment, the light emitted from the light source 2 can be efficiently incident on the light guide 1.

  (2) The short axis Ky of the spheroid K is preferably located farther from the light source 2 than the exit surface 31 a of the convex lens portion 31. An area where light is reflected in the total reflection lens section 33, that is, an area that functions as a total reflection lens increases, and the amount of light that can be reflected by the total reflection lens section 33 toward the light guide 1 can be increased. In addition, it is possible to reliably obtain an effect of guiding the spheroid K farther away from the focal point G2 of the spheroid K.

  (3) The ratio (X / Y) of the minor axis length Y to the major axis length X of the spheroid K is preferably 1.6 to 2.1. The light reflected by the total reflection lens unit 33 enters the light guide 1 at a small incident angle α. The light incident on the light guide 1 can be made larger than the critical angle by increasing the angle β toward the peripheral surface 11 of the light guide 1. Therefore, excessive light leakage from the light guide 1 can be suppressed, and the light guide 1 can be guided far away. Moreover, the shape of the total reflection lens part 33 becomes a shape suitable for shaping | molding, and the moldability of a total reflection lens part improves.

  (4) It is preferable that the other focal point G2 of the spheroid K is located in a portion of the light guide 1 surrounded by the guide lens portion 32. Since the focal point G2 is located in a portion surrounded by the guide lens portion 32 in the light guide 1, the light guide 1 is not curved or deformed near the focal point G2. For this reason, the light condensed on the focal point G2 can be efficiently guided to a distant place.

  (5) It is preferable that the tip of the spheroid K on the other focal point G2 side is located at a portion surrounded by the guide lens portion 32 in the light guide 1. The light condensed at the focal point G2 can be guided to a far place more efficiently.

  (6) The outer peripheral surface 32 b of the guide lens portion 32 is relative to a virtual straight line R connecting the light source 2 and the boundary portion S between the condensing surface 31 b of the convex lens portion 31 and the inner peripheral surface 33 a of the total reflection lens portion 33. It is preferable that they are arranged at intersecting positions. For this reason, the light incident near the boundary portion S between the convex lens portion 31 and the total reflection lens portion 33 surely enters the guide lens portion 32, and is reflected by the outer peripheral surface 32 b of the guide lens portion 32, thereby guiding the light guide 1. It is reliably incident on the light guide 1 from the peripheral surface 11.

  (7) The refractive index of the light guide 1 and the shape of the spheroid K are set so that the light incident on the light guide 1 travels toward the peripheral surface 11 of the light guide 1 at an angle β equal to or greater than the critical angle. It is preferable that In this case, most of the light traveling toward the peripheral surface in the light guide is totally reflected by the peripheral surface, and excessive light leakage from the peripheral surface can be suppressed. Therefore, it is possible to guide light far away in the light guide.

1: light guide, 10: end face, 11: side face, 2: light source, 20: light emitting face, 3: optical member, 31: convex lens part, 31a: emitting face, 31b: condensing face, 32: guide lens part, 32a: inner peripheral surface, 32b: outer peripheral surface, 33: total reflection lens part, 33a: inner peripheral surface, 33b: outer peripheral surface (elliptical arc surface), 34: light guide housing space, 35: light source space, D: guide lens G1, G2: focal point of spheroid, K: spheroid, R: virtual straight line, S: boundary between convex lens part and total reflection lens part, Ky: minor axis of spheroid , X: major axis length of spheroid, Y: minor axis length of spheroid

Claims (7)

A lighting device comprising a light source, a light guide, and an optical member disposed between the light source and the light guide,
The optical member includes a convex lens portion positioned between the light source and an end surface of the light guide, a total reflection lens portion protruding from the convex lens portion toward the periphery of the light source, and a periphery of the light guide. A guide lens portion for holding the surface,
The convex lens portion has an exit surface facing the end face of the light guide, and a condensing surface curved in a convex shape toward the light source and having a diameter smaller than the diameter of the exit surface,
The outer peripheral surface of the total reflection lens part is an elliptical arc surface forming a part of a spheroid, and the light source is located at one of the two focal points of the spheroid, and the other is in the light guide. Located in the
An illuminating device having a relationship of D ≧ Y, where D is a diameter of an outer peripheral surface of the guide lens portion and Y is a minor axis length of the spheroid.   The illuminating device according to claim 1, wherein the minor axis of the spheroid is located farther from the light source than the emission surface of the convex lens portion.   The lighting device according to claim 1 or 2, wherein a ratio of a minor axis length to a major axis length of the spheroid is 1.6 to 2.1.   The illuminating device according to claim 1, wherein the other focal point of the spheroid is located in a portion surrounded by the guide lens portion in the light guide.   The illumination device according to any one of claims 1 to 4, wherein a tip on the other focal side of the spheroid is located at a portion surrounded by the guide lens portion in the light guide.   The outer peripheral surface of the guide lens unit is disposed at a position that intersects a virtual straight line connecting the light source and the boundary between the condensing surface of the convex lens unit and the inner peripheral surface of the total reflection lens unit. The lighting device according to claim 1.   The refractive index of the light guide and the shape of the spheroid are set so that light incident on the light guide travels at an angle greater than a critical angle toward the peripheral surface of the light guide. The illuminating device in any one of 1-6.

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