JP2015103303A - Light guiding optical element and light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently guide light from a light source.SOLUTION: A collector-type light guide 8 includes: a plurality of outer circumferential light guide paths 86A, 86B, and 86C stacked concentrically about a central light guide path 85 extending from an incident end 81 to an output end 82, and is configured so that the central light guide path 85 and the outer circumferential light guide paths 86A, 86B, and 86C differ in refraction index, the outer circumferential light guide paths 86A, 86B, and 86C are arranged to be higher in refraction index as being closer to the central light guide path 85, guided light is collected to the central light guide path 85 while the light is sequentially refracted, and the light is guided from the incident end 81 to the output end 82.

Description

  The present invention relates to a light guiding technique.

In the medical field and the like, endoscopes for observing the inside of a body cavity are widely used. 2. Description of the Related Art Endoscopes typically include a light guide that guides illumination light to an observation location, and a light source device that makes illumination light incident on the light guide is known (see, for example, Patent Document 1 and Patent Document 2). .
In recent years, a method of integrating a plurality of LED chips in an LED case has been widely used to easily increase the output.

JP 2012-105715 A JP 2011-200380 A

  However, an LED light source in which a plurality of LED chips are integrated has a relatively large light emitting portion, and the emitted light is mounted at a position deviated from the optical axis. Yes. For this reason, in order to efficiently guide the light emitted from the light source including the dispersed light component to the incident surface of the light guide, a complicated optical system composed of a plurality of optical elements is required, and the optical system of the light source device is complicated. It is not easy.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a light guide optical element and a light source device capable of efficiently guiding light from a light source including a dispersed light component.

  To achieve the above object, the present invention comprises a plurality of outer peripheral light guides stacked concentrically around a central light guide extending from an incident end to an output end, the central light guide, and Each of the outer peripheral light guides has a different refractive index, and is arranged so that the refractive index increases as it approaches the side of the central light guide, and collects the light guided while sequentially refracting the light into the central light guide, and the incident end portion. A light guide optical element is provided in which light is guided from a light source to an output end.

  In the optical element for light guide according to the present invention, each of the central light guide path and the plurality of outer peripheral light guide paths has a common focal point, and the other focal point approaches the central light guide path side. It has a spheroid shape close to the exit end.

  According to the present invention, in the optical element for light guide, each outer peripheral surface of the outer peripheral light guide has a shape that totally reflects light incident from the incident end.

  According to the present invention, in the above-described optical element for light guide, an end surface of the emission end portion is formed into a spherical shape on which emitted light is condensed.

  According to the present invention, in the above-described optical element for light guide, a surface excluding an end face of the output end portion of the outermost peripheral light guide path is covered with a reflective film.

  According to the present invention, in the above-described optical element for light guide, a recess for accommodating a light source is formed at the incident end.

  According to the present invention, in the optical element for light guide described above, an elliptical reflecting mirror that connects the light source is provided at the incident end.

  According to the present invention, in the above-described optical element for light guide, an elliptical reflecting mirror that condenses outgoing light is provided at the outgoing end portion.

  Further, the present invention is characterized in that, in the above-described optical element for light guide, an elliptical reflecting mirror extending from the first focal point to the second focal point is provided.

  According to another aspect of the present invention, there is provided a light source that includes the light guide optical element according to any one of the above, and that has light having a dispersed angle component incident on an incident end of the light guide optical element. A light source device is provided, wherein a light guide is disposed at an emission end of the light guide optical element, and the light of the light source is guided, condensed, and incident on the light guide.

  According to the present invention, it has a plurality of outer peripheral light guides that are concentrically stacked around a central light guide, and each of the central light guide and the plurality of outer peripheral light guides has a different refractive index, and the central light guide The light beam is arranged so that the refractive index increases as it approaches the side of the light source, and the light guided while being refracted is collected in the central light guide and guided from the incident end to the output end. Can be efficiently collected by collecting them in the central light guide.

It is a perspective view which shows the structure of the light source device which concerns on 1st Embodiment of this invention. It is a disassembled perspective view of a light source device. It is a disassembled perspective view of a holder unit. It is a perspective view which shows schematic structure of a condensing type light guide. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is a schematic explanatory drawing of the light guide in an outer periphery light guide. It is an enlarged view of the incident part of a condensing type light guide. It is an optical path schematic explanatory drawing of the incident light in the incident end part of a condensing type light guide. It is an enlarged view of the emission part of a condensing type light guide. It is a perspective view which shows the structure of the condensing type light guide which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view which shows schematic structure inside a condensing type light guide. It is a perspective view which shows schematic structure of the light guide provided with the condensing type light guide which concerns on the 1st modification of this invention. It is a perspective view which shows schematic structure of the light guide provided with the condensing type light guide which concerns on the 2nd modification of this invention. It is a perspective view which shows schematic structure of the light guide provided with the condensing type light guide which concerns on the other modification of a 1st and 2nd modification. It is a perspective view which shows schematic structure of the light guide provided with the condensing type light guide which concerns on the 3rd modification of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a perspective view showing a configuration of a light source device 1 according to the present embodiment, and FIG. 2 is an exploded perspective view of the light source device 1. In FIG. 1, the cover case 6 is indicated by a virtual line in order to facilitate understanding of the internal structure of the light source device 1.
As shown in FIG. 1, the light source device 1 makes light incident on a light guide 2 included in the endoscope, and the incident light is guided to an observation portion of the endoscope through the light guide 2 to illuminate light. As irradiated.
As shown in FIGS. 1 and 2, the light source device 1 of this embodiment includes a substrate box 3, a front cover 4, a back cover 5, a cover case 6, a light source unit 7, and a condensing light guide. A body 8, a holder unit 9, and a heat radiating fan 15 are provided.

The substrate box 3 has a substantially plate shape with a small thickness, and has a lower case 10 and an upper case 11 as shown in FIG. 2, in which a light source substrate 12 and a power terminal block 13 are housed. ing.
The light source substrate 12 includes various circuits such as a power supply circuit that generates lighting power for the light source unit 7 and an LED drive circuit that controls lighting. The power supply terminal block 13 is a terminal block for connecting an electric wire of an external power source drawn from a wire inlet (not shown) and an electric wiring extending from the light source substrate 12.
The substrate box 3 is disposed on the bottom surface of the light source device 1, and the light source unit 7, the condensing light guide 8, and the holder unit 9 are assembled on the top surface 11 </ b> A of the substrate box 3.

  The front cover 4 and the back cover 5 are rectangular plate materials that are provided at one end and the other end of the substrate box 3 and respectively constitute the front surface and the back surface of the light source device 1. A mounting hole 14 is opened in the surface of the front cover 4, and the light guide 2 is mounted in the mounting hole 14. The cover case 6 surrounds the front cover 4 and the back cover 5, and the front cover 4, the back cover 5, and the cover case 6 constitute a case body of the light source device 1 having a substantially rectangular parallelepiped shape. Although not shown in FIG. 2, an exhaust port is formed in the back cover 5 at a position corresponding to the heat radiating fan 15.

The light source unit 7 includes an LED 20 as an example of a light emitting element, an LED substrate 21 on which the LED 20 is mounted, and a heat dissipation unit 22 provided on the back surface of the LED substrate 21. Incident on the body 8.
The LED substrate 21 is, for example, an aluminum substrate having high thermal conductivity, is formed in a substantially rectangular shape, and the LED 20 is mounted in the approximate center of the mounting surface. The LED 20 is a so-called surface mount type LED package in which an LED chip is sealed in a 1.2 cm square case body 23 with a transparent resin sealing body 24, and its optical axis K is on the mounting surface of the LED substrate 21. It is set to be almost vertical. The LED 20 has a light emitting point 20A (FIG. 5) by providing a large number of LED chips on the case body 23, and the light output is increased by increasing the degree of integration of the LED chips.
The light source unit 7 is mounted so as to be substantially perpendicular to the upper surface 11A of the substrate box 3, so that the optical axis K of the LED 20 is disposed substantially parallel to the upper surface 11A.
The light source unit 7 is controlled to be turned on by an LED drive circuit included in the light source substrate 12. As the LED 20 of the light source unit 7, an element having an appropriate emission wavelength is selected according to the purpose of use of the endoscope and the material of the light guide 2.

The heat dissipating unit 22 is a member that is provided on the back surface of the LED substrate 21 and dissipates heat from the LED 20 on the mounting surface side through the LED substrate 21, and includes a large number of heat dissipating fins 22 </ b> A extending substantially vertically from the back surface of the LED substrate 21. ing. These heat radiating fins 22 </ b> A are provided over substantially the entire surface of the LED substrate 21.
The upper surface 11A of the substrate box 3 is provided with a vent hole 25 immediately below the heat dissipating fin 22A of the heat dissipating unit 22, and the heat dissipating fin 22A is cooled by the air blown from the vent hole 25. The air blown from the vent hole 25 is introduced from the front of the light source device 1. That is, in the surface of the front cover 4, the air inlet 26 is formed at a position near the lower end thereof, that is, a position corresponding to the front surface of the substrate box 3. As shown in FIG. 2, the front surface of the board box 3 is open, and outside air can be introduced into the inside through the air inlet 26. A heat radiating fan 15 for exhausting the internal air of the light source device 1 from the back cover 5 is disposed between the back cover 5 and the heat radiating unit 22. The outside air is taken into the interior of the air and is blown from the air vent 25 of the upper case 11 to the heat radiating fins 22A. When the outside air passes through the substrate box 3, the light source substrate 12 in the substrate box 3 is also air-cooled.
The condensing light guide 8 is for making the light of the light source unit 7 incident on the holder unit 9 and its configuration will be described later.

FIG. 3 is an exploded perspective view of the holder unit 9.
The holder unit 9 includes a light guide holder 27 and a holder fixing bracket 28.
The light guide holder 27 holds the light guide 2 and positions the light guide 2 with respect to an exit end portion 82 (focal point F1, which will be described later, FIG. 5) of the condensing light guide 8. 30. The engaging flange 29 is disposed facing the mounting hole 14 of the front cover 4 and engages with a locking piece provided at the tip of the light guide 2. The holding cylinder 30 holds the portion inserted from the locking piece of the light guide 2. When the light guide holder 27 engages the light guide 2, the incident end face 32 (FIG. 4) at the tip of the light guide 2 is positioned at the focal point F <b> 1 of the condensing light guide 8.
The holder fixing bracket 28 is fixed to the substrate box 3 and supports the holding cylinder 30 of the holder unit 9.

FIG. 4 is a perspective view showing a schematic configuration of the concentrating light guide 8. 5 is a cross-sectional view taken along line AA in FIG. 4, and FIG. 6 is a cross-sectional view taken along line BB in FIG. In FIG. 4, the hatching of the cross section is omitted to avoid the drawing from becoming complicated.
As shown in FIGS. 4 and 5, the condensing light guide 8 is a transmissive optical element that guides the light of the LED 20 and condenses it on the incident end face 32 of the light guide 2. As described above, the LED 20 has a light emitting point 20A formed by integrating a large number of LED chips, and the light output is enhanced by increasing the degree of integration of the LED elements.

However, as the number of LED chips increases, the size D1 of the light emitting point 20A also increases, and specifically, the size of the light emitting point 20A is a 3 mm square size, which is larger than a general one. It has become.
In general, as an optical element for condensing the light at the light emitting point 20A of the LED 20 onto the incident end face 32 of the light guide 2, an elliptical reflector having the light emitting point 20A and the incident end face 32 as focal points can be cited. However, in the elliptical reflecting mirror, the light collection efficiency decreases as the light emitting point 20A as the light source increases, and the amount of light collected on the incident end face 32 of the light guide 2 is lost. is there.
Therefore, in the present embodiment, the light emitted from the LED 20 is guided to the incident end face 32 of the light guide 2 and collected using the condensing light guide 8 which is a transmission type optical element using a waveguide structure. It is said.

  As shown in FIGS. 4 and 5, the concentrating light guide 8 has a substantially spherical shape extending long and linearly. More specifically, as shown in FIG. 6, the center line Oa is used as the rotation axis. The rotating body is formed and guided in the direction of the center line Oa. That is, as shown in FIG. 5, the concentrating light guide 8 has an incident end 81 for receiving the emitted light of the LED 20 at one end, and guides the incident light from the incident end 81 to the other end. The other end has an emission end 82 for emitting the guided light.

As shown in FIGS. 5 and 6, the concentrating light guide 8 includes a central light guide 85 having a circular cross section extending along the center line Oa in the light guide direction, and the central light guide 85 at the center. A plurality of (three in this embodiment) outer peripheral light guides 86A, 86B and 86C are stacked concentrically, and the surface of the outermost peripheral light guide 86C is covered with a reflective film 87 formed by aluminum vapor deposition or the like. Has been. Further, the central light guide path 85 and the outer peripheral light guide paths 86A, 86B, 86C are formed of a transparent light guide material, and the refractive indexes n1 to n4 are not the same, and the closer to the center light guide path 85 side, the closer the values are. The refractive index is increased, and the refractive indexes n1>n2>n3> n4 are satisfied.
As a result, a higher light confinement effect is obtained in the light guide on the center side, so that the light guided through each of the outer light guides 86A, 86B, 86C is gradually collected in the center light guide 85 while repeating refraction.

More specifically, when light is incident on the central light guide 85 and the outer peripheral light guides 86A, 86B, 86C from the incident end portion 81, the central light guide 85 has the largest refractive index n1, so that the center Most of the light incident on the light guide 85 travels through the central light guide 85 as it is. On the other hand, in the outer peripheral light guides 86A, 86B, 86B, since the refractive index is higher in the central light guide, the incident light Ea incident on each is reflected to the inner peripheral side by the outer peripheral surface 88 as shown in FIG. Incident on the inner light guide path and gradually gathered in the central light guide path 85 as the light is guided.
As a result, most of the light emitted from the light flux collected in the central light guide path 85 is emitted from the emission end portion 82.

  In the condensing light guide 8, the central light guide 85, the outer peripheral surfaces 88 of the outer peripheral light guides 86A, 86B, and 86C, and the refractive indexes n1, n2, n3, and n4 totally reflect the incident light Ea. It is configured to guide light. That is, as shown in the schematic explanatory diagram of FIG. 7, for example, incident light Ea that has entered the outermost peripheral light guide path 86 </ b> C is totally reflected by the outer peripheral surface 88 at a predetermined incident angle θ <b> 1 </ b> C, and the inner peripheral light guide path 86 </ b> B. , 86A sequentially, and reaches the central light guide path 85. When the light enters the outer light guides 86B and 86A sequentially from the outer light guide 86C, the angles θ2C and θ2B corresponding to the refractive indexes n3 and n2 and the incident angles θ1C and θ1B on the respective outer peripheral surfaces 88 according to Snell's law. And enters the central light guide 85 from the outer peripheral light guide 86A at an incident angle θ1A. Then, the light enters the outer peripheral surface 88 of the central light guide path 85 at a refraction angle θ2A and is reflected at a reflection angle θ. The reflection angle θ is designed to be larger than the critical angle, so that the light incident through the outer light guides 86B and 86A in order from the outer light guide 86C to the center light guide 85 is incident on the central light guide 85. Will be guided.

FIG. 8 is an enlarged view of the incident end 81 of the condensing light guide 8.
As shown in FIG. 8, the concentrating light guide 8 has an incident end 81 formed with a spherical recess 89 that is recessed along the light guiding direction. More specifically, the condensing light guide 8 is reduced in diameter on the incident end portion 81 side, and the recessed portion 89 is formed by denting the entire surface of the reduced end surface in the light guiding direction.
On the other hand, the LED 20 has a sealing body 24 made of a substantially hemispherical transparent resin that seals the light emitting point 20 </ b> A, and light is emitted from the light emitting point 20 </ b> A through the sealing body 24.

  In this embodiment, the recessed portion 89 of the incident end 81 has a shape in which the sealing body 24 is fitted with almost no gap and the sealing body 24 including the light emitting point 20A is accommodated therein. Thereby, the light component Eb radiated along the optical axis K from the light emitting point 20 </ b> A of the LED 20 enters the central light guide 85, travels away from the optical axis K, and deviates from the central light guide 85. Ec can also be incident on the outer peripheral light guides 86A, 86B, 86C on the outer side. As a result, almost all of the emitted light of the LED 20 is incident on the condensing light guide 8 including the dispersed light component Ec, so that the light use efficiency is enhanced.

FIG. 9 is a schematic explanatory view of an optical path of incident light at the incident end 81 of the condensing light guide 8.
As shown in FIG. 9, the dispersed light component Ec of the LED 20 is the entire surface of the portion deviated from the optical axis K of the light emitting point 20 </ b> A in addition to the dispersed light component Ec <b> 1 radiated radially from the optical axis K of the light emitting point 20 </ b> A. The dispersion light component Ec2 radiated from is included. These dispersed light components Ec1 and Ec2 are all incident on one of the outer peripheral light guides 86A, 86B, and 86C. In each of the outer peripheral light guide paths 86A, 86B, 86C, the outer peripheral surface 88 has a substantially spheroidal shape in order to totally reflect the dispersed light component Ec and guide it in the direction of the optical axis K.

As described above, most of the light guided through each of the outer peripheral light guides 86A, 86B, 86C is gradually collected by the central light guide 85 due to total reflection at the outer peripheral surface 88, and the diffusion angle γ (optical axis K). Depending on the angle of the diffusion direction of the light component with respect to FIG. 8, the light is guided as it is in the outer peripheral light guides 86A, 86B, 86C.
Thus, substantially all of the emitted light from the LED 20 is incident on the condensing light guide 8 including the dispersed light component Ec, and most of the light is collected in the central light guide 85 and emitted. In this condensing light guide 8, as shown in FIG. 8 and FIG. 9, the central light guide 85 has a cross-sectional diameter smaller than the size D1 of the light emitting point 20A. However, light will be efficiently collected in a small area.

FIG. 10 is an enlarged view of the emission end portion 82 of the concentrating light guide 8.
As shown in FIG. 10, the exit end portion 82 includes an exit surface 82A formed by exposing the end face from the reflective film 87. From the exit surface 82A, the central light guide path 85 and the outer peripheral light guide paths 86A, 86B, 86C. The light which guided each of these is emitted. The exit surface 82A is formed in a convex spherical shape in which at least the exit end surface 85A of the central light guide path 85 has a focal point F1 corresponding to the NA of the entrance end surface 32 at the tip of the light guide 2, and the emitted light is transmitted to the light guide 2. It is designed to be incident efficiently.

More specifically, in order for light incident on the light guide 2 to be guided through the light guide 2, when the numerical aperture of the light guide 2 is NA, the incident angle θ of the incident light is the maximum incident angle θmax = Arcsin ( NA) must be less than or equal to
In general, in an endoscope, as the numerical aperture NA of the light guide 2 is smaller, the directivity of illumination light is improved and a narrow range can be illuminated. Therefore, in this light source device 1, a light guide 2 having a numerical aperture NA of 0.2 to 0.35 (maximum incident angle θmax = 11.5 ° to 20 °) and an aperture diameter D2 of about 4 mm is used. Both the numerical aperture NA and the opening diameter D2 are smaller than those of a general light guide. Further, in the light source device 1, the light emitting point 20A has a size D1 of 3 mm square for increasing the output of the LED 20. Thus, since the light emitting point 20A is larger than an ideal point light source, for example, even if a condensing optical system for condensing the radiated light of the light emitting point 20A of the LED 20 on the incident end face 32 of the light guide 2 is provided. The aberration at the end face 32 is large, and not only can the light not be within the numerical aperture NA range of the light guide 2, but also light components that deviate from the aperture diameter D2 are generated.

On the other hand, in the condensing light guide 8, the diameter D3 of the central light guide 85 at the emission end 82 is smaller than the opening diameter D2 of the light guide 2, as shown in FIG. Therefore, most of the light emitted from the LED 20 enters the concentrating light guide 8 and is collected in the central light guide 85 and is emitted from a diameter D3 smaller than the opening diameter D2 of the light guide 2. The exit end face 85A of the central light guide 85 is formed in a convex spherical shape having a focal point F1 corresponding to the NA of the entrance end face 32 at the tip of the light guide 2 as described above. However, it efficiently enters the incident end face 32 having the aperture diameter D2 within the numerical aperture NA range of the light guide 2.
Further, the light that has been guided through each of the outer peripheral light guides 86A, 86B, and 86C of the concentrating light guide 8 and emitted from the output surface 82A has an outer peripheral surface 88 of these outer peripheral light guides 86A, 86B, and 86C having an elliptical surface. Configure. For this reason, the light guided through the outer peripheral light guide paths 86A, 86B, 86C by bringing these outer peripheral surfaces 88 close to the shape of a so-called elliptical reflecting surface having the light emitting point 20A and the incident end surface 32 as the focal points. Can be efficiently condensed and incident on the incident end face 32 of the light guide 2, and the efficiency can be further increased.

  Thus, according to this embodiment, the concentrating light guide 8 has the plurality of outer peripheral light guides 86A, 86B, 86C stacked concentrically around the center light guide 85, and the center light guide 85 and the plurality of outer peripheral light guides 86A, 86B, 86C are different in refractive index, and are arranged so that the refractive index becomes higher toward the side of the central light guide 85, and the light guided while sequentially refracting is centrally guided. The light is collected in the optical path 85 and guided from the incident end 81 to the exit end 82. Thereby, the radiated light of LED20 containing the dispersed light component Ec can be collected in the center light guide path 85, and can be radiate | emitted efficiently.

  Further, according to the present embodiment, the outer peripheral surfaces 88 of the outer peripheral light guide paths 86A, 86B, 86C are configured to totally reflect the light incident from the incident end portion 81. Thereby, even if the dispersed light component Ec of the radiated light deviates from the central light guide path 85 and enters the outer peripheral light guide paths 86A, 86B, 86C, these are guided to the emission end portion 82 and directed inward. When reflected, it can be collected in the central light guide 85.

Further, according to the present embodiment, the concave portion 89 that accommodates the light emitting point 20 </ b> A of the LED 20 together with the sealing body 24 is formed in the incident end portion 81.
Thereby, the light component Eb radiated along the optical axis K from the light emitting point 20 </ b> A of the LED 20 enters the central light guide 85, travels away from the optical axis K, and deviates from the central light guide 85. Ec can also be incident on the outer peripheral light guides 86A, 86B, 86C on the outer side. Accordingly, since almost all of the emitted light from the LED 20 is incident on the condensing light guide 8 including the dispersed light component Ec, the light utilization efficiency is improved.

  Further, according to the present embodiment, since the exit surface 82A of the exit end portion 82 has a spherical shape for collecting the exit light, even if the LED 20 contains a large amount of the dispersed light component Ec, they are collected in the central light guide 85. The light can be efficiently focused on the predetermined focal point F1, and can be efficiently incident on the light guide 2.

  In addition, according to the present embodiment, since the surface of the outermost peripheral light guide path 86A is covered with the reflective film 87, leakage light can be suppressed and light utilization efficiency can be increased.

[Second Embodiment]
FIG. 11 is a perspective view showing a configuration of the concentrating light guide 108 according to the present embodiment, and FIG. 12 is a longitudinal sectional view showing a schematic configuration inside the concentrating light guide 108.
The concentrating light guide 108 has a plurality of outer peripheral light guides 186A, 186B, and 186C concentrically stacked around a center light guide 185 extending from the incident end 181 to the output end 182. Each of the optical path 185 and the plurality of outer peripheral light guide paths 186A, 186B, and 186C has a different refractive index n1, n2, n3, and n4, and is arranged so that the refractive index becomes higher toward the center light guide path 185 side (that is, n1 >N2>n3> n4), a condensing type according to the first embodiment in that the light that is guided while being refracted is collected in the central light guide 185 and guided from the incident end 181 to the output end 182. The configuration is the same as that of the light guide 8.

  On the other hand, in the condensing light guide 8 of the first embodiment, all of the outer peripheral light guides 86A, 86B, 86C extend from the incident end 81 to the emission end 82. The concentrating light guide 108 of the embodiment is greatly different in configuration in that each of the outer peripheral light guide paths 186A, 186B, and 186C is cut in the middle of the emission end portion 182.

More specifically, as shown in FIG. 12, each of the central light guide 185 and the outer peripheral light guides 186A, 186B, 186C has a spheroid shape centered on the optical axis K. The central light guide 185 and the outer peripheral light guides 186A, 186B, and 186C have the light emission point 20A of the LED 20 as a common focus Fa, and the other focal points Fb are different from each other.
Specifically, the focal points Fb of the central light guide 185 and the outer peripheral light guides 186A, 186B, and 186C are located closer to the focal point Fa toward the outer light guide, and the focal points Fb are the focal points Fb1, Fb2, Assuming that the focus is Fb3 and Fb4, the focus Fb1 is set to be the farthest from the focus Fa, and then gradually approach the focus Fa in the order of the focus Fb2, the focus Fb3, and the focus Fb4. In other words, the light guide path closer to the outside is configured to be focused near the focal point Fa.

In this configuration, each of the outer peripheral surfaces 188 of the central light guide 185 and the outer peripheral light guides 186A, 186B, 186C is an intersection 90 from the outer peripheral surface 188 to the inner outer peripheral surface 188 in order from the incident end 181. It becomes a shape that intersects and breaks.
Further, in the longest central light guide path 185, the emission end face 182A of the condensing light guide 108 is formed by being cut at the position of the focal point Fb1.

When the emitted light of the LED 20 enters the incident end 181 of the concentrating light guide 108, the light enters and guides the central light guide 185 and the outer light guides 186A, 186B, and 186C, respectively. . At this time, in each of the outer peripheral light guide paths 186A, 186B, and 186C, the light guide paths closer to the outer side connect the focal points Fb2, Fb3, and Fb4 closer to the focal point Fa, so that the outer peripheral light guide paths 186A, 186B, and 186C The totally reflected light Ed enters the central light guide 185 including these focal points Fb2, Fb3, and Fb4 on the inside, and all the emitted light of the LED 20 is collected in the central light guide 185.
Since the exit end face 182A is formed at the focal point Fb1 of the central light guide 185, the incident end face 32 of the light guide 2 is disposed on the exit end face 182A, thereby increasing the light collection rate of the light collected at the focal point Fb1. In addition, the ratio of the light beam incident from the light guide 298 within the range of the numerical aperture NA of the light guide 2 is increased.

  As described above, according to the present embodiment, each of the outer peripheral light guides 186A, 186B, and 186C has an elliptical surface shape that focuses near the incident end 181 toward the outer peripheral light guide on the outer peripheral side. All of the light incident from the light can be collected and emitted to the central light guide 185 before reaching the emission end 182.

In the present embodiment, the surface of the outermost peripheral light guide path 186C may be covered with a reflective film formed by aluminum vapor deposition or the like as in the first embodiment.
In the present embodiment, the exit end face 182A of the exit end 182 may be formed in a convex spherical condensing lens shape as necessary.

  The above-described first and second embodiments are merely illustrative of one aspect of the present invention, and can be arbitrarily modified and applied without departing from the spirit of the present invention.

  For example, in each of the above-described embodiments, the collected light is incident from the emission end portions 82 and 182 that are disposed facing each other in the vicinity of the incident end surface 32 of the light guide 2 while the incident end portions 81 and 181 are disposed on the LED 20 that is a light source. The concentrating light guides 8 and 108 are illustrated. However, the present invention is not limited to this, and other optical elements may be interposed between the incident end portions 81 and 181 and the LED 20 and / or between the output end portions 82 and 182. Hereinafter, the modified example will be described.

FIG. 13 is a perspective view showing a schematic configuration of a light guide 298 provided with a condensing light guide 208 according to a first modification. In addition, in the same figure, the same code | symbol is attached | subjected about the member and site | part same as 1st Embodiment, and the description is abbreviate | omitted.
In the condensing light guide 208, the LED 20 is disposed at the incident end 281, and an elliptical reflecting mirror 295 that connects the light guide 2 to the incident end surface 32 is connected to the emission end 282. Thus, a light guide 298 is configured. The condensing light guide 208 has a shape obtained by cutting the condensing light guide 8 of the first embodiment on the incident end 81 side from the center in the longitudinal direction, and light incident from the incident end 281 is incident on the condensing light guide 208. The light is generally collected by the central light guide 285 and is incident on the elliptical reflecting mirror 295 from the emission end 282. The elliptical reflecting mirror 295 is a condensing optical element having a first focal point Fd and a second focal point Fe on the LED 20 and the incident end face 32 of the light guide 2, respectively.

In this light guide 298, an elliptical reflecting mirror 295 is connected to the emission end 282 of the condensing light guide 208, so that almost all components of the emitted light of the LED 20 are collected. Can be guided to the elliptical reflecting mirror 295 and controlled by the elliptical reflecting mirror 295 to be incident on the incident end face 32 of the light guide 2.
Further, in the light guide 298, the central light guide 285 and the outer peripheral light guides 286A, 286B, and 286C of the condensing light guide 208 are respectively the same as the first focal point Fd and the second focal point as the elliptical reflector 295. It is a spheroid with Fe, and the condensing rate is increased by efficiently condensing the radiated light of the LED 20 on the second focal point Fe, and the light guide 2 is guided in the numerical aperture NA range. The ratio of the luminous flux incident from the optical device 298 is increased.

FIG. 14 is a perspective view showing a schematic configuration of a light guide 398 including a condensing light guide 308 according to a second modification. In addition, in the same figure, the same code | symbol is attached | subjected about the member and site | part same as 1st Embodiment and a 1st modification, and the description is abbreviate | omitted.
In this condensing light guide 308, an exit end 382 is disposed in the vicinity of the entrance end face 32 of the light guide 2, and light emitted from the exit end 382 enters the light guide 2 directly. The incident end 381 is connected to an elliptical reflecting mirror 395 that connects the LED 20 that is a light source, so that a light guide 398 is configured. The elliptical reflecting mirror 395 has a first focal point Fd and a second focal point Fe on the LED 20 and the incident end face 32 of the light guide 2, respectively, similarly to the elliptical reflecting mirror 295 of the first modification.

As described above, the light guide 398 in which the elliptical reflecting mirror 395 is connected to the incident end 381 of the condensing light guide 308 has the following effects.
That is, in the configuration in which the elliptical reflecting mirror 395 is used alone, the collection at the second focal point Fe is caused by the size D1 of the light emitting point 20A of the LED 20 (that is, the dispersed light component Ec having the dispersed angular component γ). The light characteristics are deteriorated, and the incident efficiency to the incident end face 32 of the light guide 2 is deteriorated. On the other hand, in this light guide 398, the condensing light guide 308 is connected to the tip of the elliptical reflecting mirror 395, so that the emitted light of the elliptical reflecting mirror 395 including the dispersed light component Ec is Then, the light is guided through the condensing light guide 308 and collected and emitted from the central light guide 385, so that the light can enter the incident end face 32 of the light guide 2 efficiently.
Further, in this light guide 398, the central light guide 385 and the outer peripheral light guides 386A, 386B, and 386C of the condensing light guide 308 are the same as the first focal point Fd and the second focal point, respectively, as the elliptical reflector 395. It is a spheroid having Fe, and thereby the light emitted from the LED 20 is more efficiently collected on the second focal point Fe, thereby increasing the light collection rate, and further, the numerical aperture NA range of the light guide 2 Thus, the ratio of the light beam incident from the light guide 398 is increased.

As shown in FIG. 15, a concentrating light guide 208 according to the first modification and a concentrating light guide 308 according to the second modification are provided, and the LED 20 and the light are provided between them. You may comprise the light guide 498 connected to each of the incident end surface 32 of the guide 2 by the elliptical reflecting mirror 495 which has the 1st focus Fd and the 2nd focus Fe.
According to this light guide 498, almost all of the emitted light of the LED 20 can be made incident on the elliptical reflecting mirror 495 by the condensing light guide 208, and the light emitted from the elliptical reflecting mirror 495 can be condensed. The light body 308 can efficiently enter the incident end face 32 of the light guide 2.

FIG. 16 is a perspective view showing a schematic configuration of a light guide 598 including a condensing light guide 508 according to a third modification. In addition, in the same figure, the same code | symbol is attached | subjected about the member and site | part same as 2nd Embodiment, and the description is abbreviate | omitted.
The light guide 598 includes a condensing light guide 508 and an elliptical reflecting mirror 595. The condensing light guide 508 includes the condensing light guide 108 and the incident end described in the second embodiment. The configuration is generally the same except for the shape of the portion 181. That is, the incident end surface of the incident end portion 581 of the condensing light guide 508 forms a convex surface 581A that bulges toward the LED 20 that is the light source, and the incident end portion 581 has an ellipse that connects to the LED 20. A reflecting mirror 595 is connected. The elliptical reflecting mirror 595 has a first focal point Fd and a second focal point Fe on the LED 20 and the incident end face 32 of the light guide 2, respectively.

  According to the light guide 598, as in the second modification, the condensing light guide 508 is connected to the tip of the elliptical reflecting mirror 595, so that the elliptical reflecting mirror 595 including the dispersed light component Ec is output. The incident light is guided through the condensing light guide 308, collected in the central light guide 185, and emitted, so that it can efficiently enter the incident end face 32 of the light guide 2.

  In the modification shown in FIGS. 13 to 15, the configuration in which the elliptical reflecting mirror is connected to the incident end portion 81 and / or the emission end portion 82 of the condensing light guide 8 is illustrated. However, the present invention is not limited to this, and the LED 20 as the light source is the first focal point, the incident end face 32 of the light guide 2 is the second focal point, and the entire elliptical reflecting mirror extending from the first focal point to the second focal point is on the incident end side. Alternatively, the condensing light guide 8 may be provided on the exit end side. Specifically, in the modified examples shown in FIGS. 13 to 15, the elliptical reflecting mirrors 295, 395, 495 cover the outsides of the concentrating light guides 208, 308, so that these elliptical reflecting mirrors 295, 395, The condensing light guides 208 and 308 may be built in 495.

Further, in the above-described embodiments and modifications, any light source other than the LED 20 can be used as the light source.
In addition, for example, in the above-described embodiment and the modification, the configuration in which the condensing light guide extends linearly is illustrated, but a configuration in which a portion between the incident end and the exit end is bent may be used.
Further, for example, in the above-described embodiment and the modification, the shape of the recessed portion 89 of the incident end portion 81 receives substantially all of the radiated light of the light emitting point 20A of the LED 20, and the central light guide path 85 and the outer peripheral light guide path 86A. , 86B and 86C are optional as long as they can be incident on each of them.

1 Light source device 2 Light guide 20 LED
20A Light-emitting point 21 Sealing body 8, 108, 208, 308, 508 Condensing light guide (optical element for light guide)
81 Incident end portion 82 Emission end portion 82A Emission surface 85 Central light guide path 86A, 86B, 86C Outer peripheral light guide path 87 Reflective film 88 Outer peripheral surface 89 Recessed section 395, 495, 595 Elliptical mirror 398, 498, 598 Light guide Ec, Ec1, Ec2 Dispersed light component F1 Focus K Optical axis Oa Center line

Claims (10)

It has a plurality of outer peripheral light guides stacked concentrically around a central light guide extending from the incident end to the output end,
Each of the central light guide and the plurality of outer peripheral light guides has a different refractive index, and is arranged so that the refractive index increases as it approaches the central light guide. The light that is guided while being refracted sequentially is arranged. An optical element for guiding light that is collected in an optical path and guided from the incident end to the exit end.   Each of the central light guide path and the plurality of outer peripheral light guide paths has a common one of the focal points, and has a spheroid shape that becomes closer to the exit end as the other focal point approaches the central light guide path side. The optical element for light guide according to claim 1.   3. The optical element for light guide according to claim 1, wherein each outer peripheral surface of the outer peripheral light guide path has a shape that totally reflects light incident from the incident end.   The optical element for light guide according to any one of claims 1 to 3, wherein an end surface of the emission end portion is formed into a spherical shape for collecting emitted light.   The optical element for light guide according to any one of claims 1 to 4, wherein a surface excluding an end face of the output end portion of the outermost peripheral light guide path is covered with a reflective film.   The optical element for light guide according to any one of claims 1 to 5, wherein a concave portion for accommodating a light source is formed at the incident end portion.   The optical element for light guide according to claim 1, wherein an elliptical reflecting mirror that connects the light source is provided at the incident end.   The optical element for light guide according to any one of claims 1 to 7, wherein an elliptical reflecting mirror for condensing outgoing light is provided at the outgoing end portion.   The optical element for light guide according to any one of claims 1 to 5, wherein the light guide optical element is installed in an elliptical reflecting mirror extending from the first focal point to the second focal point. Comprising the optical element for light guide according to any one of claims 1 to 9,
A light source incident on the incident end of the light guiding optical element, and having light having a dispersed angle component;
A light source device, comprising: a light guide disposed at an output end of the light guide optical element; guides and collects light from the light source; and enters the light guide.

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