JP5108814B2 - Condensing optical element - Google Patents

Description

  The present invention relates to a condensing optical element.

  There are various uses for improving the energy density at the focal point by condensing light incident from each of a plurality of light sources such as a solar system for concentrating sunlight and a high-intensity laser. However, it is very difficult to design a single optical element that collects a plurality of lights having different incident angles and incident positions. For example, for use as a pumping source of a semiconductor laser pumped solid-state laser device, an optical path converter capable of increasing the energy density by extremely reducing the focal point of a linear array semiconductor laser device has been proposed (Patent Document 1). reference). The optical path changer is composed of one rotating prism configured by combining right-angle prisms.

This rotating prism is disposed in front of a linear array laser element that emits a dotted laser beam group, and receives the collimated laser beam group that is refracted in a direction substantially perpendicular to the direction of the dotted line. The laser beam from each emitter or each group of emitters is radiated by turning the laser beam at a right angle to convert it into a substantially ladder-like laser beam group, and the substantially ladder-like laser beam group is independent in two directions. It collimates and converges to the focal point to improve the density of laser energy at the focal point.
JP-A-7-98402

  However, since the optical path changer described in Patent Document 1 uses a plurality of rotating prisms arranged in an array, it is necessary to consider variations in individual optical characteristics, and high assembling accuracy cannot be obtained. For this reason, there is a problem that optical adjustment with the linear array laser element becomes complicated and the possibility of practical use is low. As described above, it is difficult to condense not only laser light but a plurality of lights having different incident angles and incident positions with a single optical element.

  The present invention has been made to solve the above-described problems, and can reversely utilize the operating principle of a light guide plate used in a backlight or the like to propagate and collect light incident from different positions. It is to provide a single condensing optical element.

  In order to achieve the above object, the invention described in each claim has the following configuration.

The invention according to claim 1 is provided with an incident surface having an incident portion on which a plurality of lights are incident at a predetermined incident angle, and at least one reflecting surface facing the incident surface, and is incident from the incident surface. A long light guide that totally reflects light between the incident surface and a reflective surface facing the incident surface and propagates in the length direction, and the thickness of the light guide and the light guide A first light guide having at least one of a width increasing toward a downstream side in the light propagation direction, a surface continuous to the incident surface, at least one reflecting surface facing the surface, and the surface and the surface; A length connected to the first light guide so as to form an optical path together with the first light guide, including an output portion from which the light totally reflected and propagated between the opposing reflecting surfaces is emitted. A light guide having a scale shape, wherein at least one of the thickness of the light guide and the width of the light guide is the light propagation direction. Includes a second light guide which decreases toward the downstream side, and the emitted position or the emission direction of the light emitted from the emitting portion is different depending on the position in the width direction of the light of the incident portion is incident A condensing optical element in which at least one of the reflecting surface facing the incident surface and the reflecting surface facing the surface is composed of a plurality of planes whose normals are inclined toward the central direction and intersect each other .

  The invention according to claim 2 is the condensing optical element according to claim 1, wherein the exit portion is an exit end face that intersects the surface at an angle at which the propagated light exits beyond a critical angle. .

Note that the reflection surface facing the incident surface may include a curved surface obtained by rotating a straight line or a curve intersecting the rotation axis around the rotation axis .

  The invention according to each claim has the following effects.

According to the first aspect of the present invention, by conversely using the operating principle of the light guide plate used for the backlight or the like, the single incident optical element propagates and collects the incident light from different positions. There is an effect that can be. In addition, there is an effect that the condensing characteristic of the emitted light can be controlled.

  According to the second aspect of the present invention, there is an effect that the condensing property of the emitted light is improved and the emitted light can be efficiently extracted.

  According to the invention described in claim 3, there is an effect that the condensing characteristic of the emitted light can be controlled.

(A)-(C) are schematic which shows the structure of the condensing optical element which concerns on the 1st Embodiment of this invention. It is a disassembled perspective view when the condensing optical element of FIG. 1 is decomposed | disassembled into two light guides. (A) And (B) is the schematic which shows the condensing operation | movement of a condensing optical element. It is an analysis model (meridian approximate model) in the meridian plane of a condensing optical element. (A)-(D) are figures which show the example of the combination method of two light guides. (A)-(D) are schematic which shows the structure of the condensing optical element which concerns on the 2nd Embodiment of this invention. (A)-(C) are schematic which shows the structure of the modification of the condensing optical element which concerns on the 2nd Embodiment of this invention. (A) And (B) is a figure explaining that the propagation characteristic of a light guide changes with the polyhedral shape of a reflective surface. (A)-(D) are schematic which shows the structure of the condensing optical element which concerns on the 3rd Embodiment of this invention. It is a disassembled perspective view when the condensing optical element of FIG. 9 is decomposed | disassembled into two light guides. It is the schematic which shows the design concept of the modification of the condensing optical element which concerns on 3rd Embodiment. (A)-(D) are schematic which shows the structure of the modification of the condensing optical element which concerns on the 3rd Embodiment of this invention. It is a schematic perspective view which shows an example of the formation method of the light guide body of the upstream of the condensing optical element shown in FIG. (A) is a schematic perspective view which shows the structure of the condensing optical element which concerns on the 4th Embodiment of this invention, (B) is decomposition | disassembly when this condensing optical element is decomposed | disassembled into two light guides It is a perspective view. (A)-(C) are figures which show the modification of the condensing optical element which concerns on 4th Embodiment.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

<First Embodiment>
(Schematic configuration of condensing optical element)
1A to 1C are schematic views showing the configuration of a condensing optical element according to the first embodiment of the present invention. 1A is a perspective view of the condensing optical element, FIG. 1B is a plan view of the condensing optical element viewed from above, and FIG. 1C is an optical axis of the condensing optical element. FIG. FIG. 2 is an exploded perspective view when the condensing optical element is disassembled into two light guides. In the following description, it is assumed that the light incident on the condensing optical element propagates in the positive direction in geometric optics (from left to right in the drawing). The expressions “upstream side” and “downstream side” are used with respect to the light propagation direction.

As shown in FIGS. 1A to 1C, the condensing optical element 10 according to the first embodiment is a long plate-shaped light guide (light guide plate) whose longitudinal direction is the light propagation direction. . The condensing optical element 10 includes an incident surface 12 having an incident portion on which light is incident, a first reflecting surface 14 facing the incident surface 12, and a first connecting surface of the incident surface 12 and the first reflecting surface 14. and second reflective surfaces 16 ₁ and the third reflecting surface 16 _2, is condensed light is configured to include an exit end face 18 of the emission part for emitting.

In this embodiment, the second reflecting surface 16 ₁ and the third reflecting surface 16 ₂ constitutes the opposing side surface of the light guide plate, the incident surface 12, a first reflecting surface 14, the second confining light at four surfaces of the reflecting surfaces 16 ₁ and the third reflecting surface 16 ₂ of the. The incident portion (not shown) is located at the upstream end of the incident surface 12. An emission end face 18 that is an emission part is formed at the distal end portion on the downstream side. The exit end face 18 is formed to form a predetermined angle with respect to the entrance face 12 so that the propagating light exits beyond the critical angle.

(Condensing operation of condensing optical element)
With reference to FIG. 2, the condensing operation | movement of the condensing optical element 10 is demonstrated. The condensing optical element 10 is integrally formed so that the light guide body 10A disposed on the upstream side and the light guide body 10B disposed on the downstream side are continuous via the transmission surface 13 which is a virtual surface. ing. The incident surface 12 is a single plane. On the other hand, the first reflection surface 14 is bent with the transmission surface 13 as a boundary, and is composed of two planes, a rectangular plane on the light guide 10A side and a trapezoidal plane on the light guide 10B side. Yes.

Light guide 10A, a second distance between the reflecting surface 16 ₁ and the second reflecting surface 16 ₂ of the (width of the light guide) is constant, which are opposite to each other, the incident surface 12 and the first facing each other An up taper is formed in which the distance from the reflecting surface 14 (the thickness of the light guide) increases toward the downstream side. The shape of the light guide 10A that forms the up taper in this way is referred to as a “wedge shape”.

Light incident at a predetermined angle from the incident part on the light guide member 10A are entrance surface 12, a first reflecting surface 14, totally reflected while propagated by the second reflecting surface 16 ₁ and the third between the reflecting surface 16 ₂ of To do. In the wedge-shaped light guide 10A, the angle of total reflection (the angle formed between the reflected light and the reflecting surface: the complementary angle of incidence on the reflecting surface) gradually decreases toward the downstream side, and the propagating light decreases from the higher order mode. It is converted to the next mode. Light that is substantially perpendicular to the transmission surface 13 (parallel light) is emitted from the transmission surface 13 that is the end surface of the light guide 10A.

On the other hand, in the light guide 10B, the distance (the thickness of the light guide) between the incident surface 12 and the first reflecting surface 14 facing each other is constant, but the second reflecting surface 161 and the _first reflecting surface 161 facing each other are constant. The space | interval (width | variety of a light guide) with ₂ reflective surfaces 162 forms the down taper which decreases toward a downstream. If the light propagation direction is the forward direction, the light guide 10B forming the down taper is a “reverse wedge” in which “wedge-like” light guides are arranged in the opposite direction. Therefore, the shape of the light guide 10B is referred to as “reverse wedge shape”.

The light incident on the light guide member 10B from the transmitting surface 13, the incident surface 12, a first reflecting surface 14, propagates while being totally reflected by the second reflecting surface 16 ₁ and the third between the reflective surface 16 _2. In the reverse wedge-shaped light guide 10B, the angle of total reflection gradually increases toward the downstream side, and the propagating light is converted from the low-order mode to the high-order mode. In the light guide 10B, the light is condensed in the width direction (horizontal direction) of the light guide. The light condensed toward the emission part is extracted from the emission end face 18 beyond the critical angle.

  Thereby, the light incident on the incident surface 12 at a predetermined angle propagates in the condensing optical element 10 and is condensed in the horizontal direction, and the condensed light is emitted from the emission end surface 18. The area of the exit end face 18 is smaller than the area of the entrance face 12, and the condensed light is emitted from a part of the exit end face 18 so as to project a large area optical image on a small area.

  Propagation / condensation by the “wedge-shaped light guide” reversely uses the operating principle of a light guide plate used for a backlight or the like. As described above, for example, condensing optics by appropriately combining a “wedge-shaped light guide” having a mode conversion function so as to exhibit desired optical characteristics such as collimation and condensing. Elements can be designed freely. Condensing optical elements according to other embodiments described below are also designed with the above-mentioned “wedge-shaped light guide” as a basic unit.

  From the viewpoint of optical characteristics, the condensing optical element 10 is understood to be an optical system similar to two cylindrical lenses arranged so as to be perpendicular to and perpendicular to the traveling direction of light incident on the optical system. be able to. That is, the condensing optical element 10 converts the incident light into parallel light by the light guide 10A disposed on the upstream side and collects the propagation light in the horizontal direction by the light guide 10B disposed on the downstream side ( For example, it has the same optical characteristics as a relay lens or a beam expander.

(Optical material for condensing optical element)
As the optical material constituting the condensing optical element 10, a material that is transparent to light having a wavelength to be guided and has a higher refractive index than a material disposed outside is used so as to function as a light guide. . For example, in the case of being disposed in the air, any material having a refractive index greater than 1 may be used, and an optical material having a refractive index of about 1.3 to 2.7 is generally used. Is not to be done. In addition, regarding the optical material, the same material can be used also for the condensing optical element according to another embodiment described below.

  In general, it is desirable to use a material having a higher refractive index so long as optical properties are not deteriorated such as causing unnecessary scattering. However, when a material having a higher refractive index is used, there is a possibility that a loss due to Fresnel reflection occurs when light enters the condensing optical element 10 from the air region. Therefore, when using a material having a higher refractive index, it is preferable to provide an antireflection means in order to reduce Fresnel reflection loss.

  In addition, a material can be appropriately selected according to the energy density of the collected light. For example, when condensing a laser beam having a high energy density, it is preferable to use a material having excellent heat resistance such as quartz. When condensing light of low energy density, such as light emitted from LEDs that emit light in the visible region or sunlight, a resin material such as acrylic resin (PMMA), polycarbonate (PC), or cycloolefin polymer (COP) is used. be able to.

(How to use condensing optical elements)
3A and 3B are schematic views showing an example of a method of using the condensing optical element. The condensing optical element of the present invention condenses light incident on the incident portion at a predetermined angle among the irradiated light, and appropriately selects the material and shape according to the light source, for example, a laser light source Various light sources such as an LED light source, sunlight, a point light source, a line light source, and a surface light source can be used. The light emitted from the light source may be any of coherent light, incoherent light, or light having a coherency degree between the coherent light and the incoherent light.

  For example, as shown in FIG. 3A, a semiconductor laser (LD) array 15 can be used as a light source. Laser light emitted from each of the plurality of LDs of the LD array 15 is applied to the incident surface 12 of the condensing optical element 10. A part of the irradiated laser light is incident at a predetermined angle from an incident portion located at the end of the incident surface 12, is condensed, and is emitted from the emission end surface 18. In addition, as shown in FIG. 3B, sunlight 21 can be used as a light source. Sunlight 21 is irradiated onto the incident surface 12 of the condensing optical element 10. A part of the irradiated sunlight can be similarly collected and taken out from the emission end face 18.

  In either case of FIGS. 3A and 3B, a lens (not shown) may be disposed on the upstream side of the incident portion, and the light condensed by the lens may be irradiated onto the incident surface 12. . Further, the light emitted from the emission end face 18 is condensed by the condenser lens 17 as necessary. For example, the light emitted from the emission end face 18 may have a large divergence angle. In such a case, in order to reduce light loss, the emitted light from the emission end face 18 can be condensed by the condenser lens 17 arranged outside, and the condensed light can be irradiated onto the object. it can.

  In addition to focusing with an externally arranged lens, the exit end face 18 may be directly processed to form a lens on the surface. As the lens, a tip ball lens, a Fresnel lens, or the like can be used. Further, reflection at the emission end face 18 can be prevented by forming an antireflection film on the surface of the light guide or adding a nanostructure having an antireflection function or a reflection reduction function. Further, an optical fiber may be directly connected to the emission end face 18 and the emitted light may be guided to the optical fiber. In addition, the condensing optical element which concerns on other embodiment demonstrated below can be used similarly.

(Propagation condition by total reflection)
Next, conditions for the incident light to be totally reflected and propagated in the condensing optical element 10 will be described. FIG. 4 is an analysis model (meridian approximation model) on the meridian plane of the condensing optical element. The condensing optical element 10 according to the present embodiment has a substantially symmetric shape in the width direction. Therefore, the light incident from the incident surface 12 is divided into a meridional ray propagating in a plane (meridian plane) including the optical axis, and a skew ray not included in the meridian plane. The meridian approximate model is a model representing the propagation behavior of meridional rays propagating in the meridian plane.

FIG. 4 illustrates a state where the light is incident from an arbitrary incident portion (point O ′) of the incident surface 12 of the light guide 10 </ b> A disposed on the upstream side and is emitted from the transmission surface 13. Entrance surface 12 and the first reflecting surface 14 is a plane to each other and intersect at an angle theta ₁ to the incident surface 12 and the first reflecting surface 14. The light incident at the incident angle θ ₂ is refracted at the refraction angle θ ₃ and enters the light guide 10A. The incident light is totally reflected and propagated between the incident surface 12 and the first reflecting surface 14, and is emitted from the transmitting surface 13 substantially perpendicularly to the transmitting surface 13.

If the thickness of the light guide 10A at the incident part is “ws”, the thickness of the light guide 10A at the transmission surface 13 is “we”, and the distance from the incident part to the transmission surface 13 is “L”, then the intersection The angle θ ₁ is determined. The optical path of the propagating light is expressed by “Snell's law” expressed by the following formula (1) and by the following formula (2) according to the intersection angle θ ₁ , the incident angle θ ₂ , and the refraction angle θ _3. It can be calculated using the “total reflection condition”.

n _A · sin θ ₂ = n _LGP · sin θ ₃ formulas (1)
In Formula (1), n _A is the refractive index of air, and n _LGP is the refractive index of the constituent material of the condensing optical element.

θ _C = sin ⁻¹ (n _A / n _LGP ) Formula (2)

In formula (2), θ _C is a critical angle. If the complementary angle of incidence on the reflecting surface does not exceed the critical angle θ _C , total reflection is performed.

  In the description of FIG. 4, the “reflection surface” means a surface where total reflection actually occurs, and is the incident surface 12 or the first reflection surface 14. In the first reflection, light incident from the incident surface 12 is reflected by the first reflecting surface 14 toward the incident surface 12. In the second reflection, the light reflected by the first reflecting surface 14 is reflected by the incident surface 12 toward the first reflecting surface 14.

In the wedge-shaped light guide 10A shown in the figure, when only total reflection between the incident surface 12 and the first reflecting surface 14 is considered, the incident angle to the first reflecting surface is (θ ₃ + θ ₁ ). The second incidence angle is (θ ₃ + 2θ ₁ ),..., The nth incidence angle is gradually increased to (θ ₃ + nθ ₁ ), and the incident complementary angle (total reflection angle) to the reflecting surface is gradually increased. Get smaller. Therefore, as described above, the propagating light is collimated and passes through the transmission surface 13. In the reverse wedge-shaped light guide 10B, on the contrary, the incident complementary angle gradually increases as the number of reflections increases. In the outgoing end face 18 formed obliquely with respect to the incident surface 12, the incident complementary angle exceeds the critical angle θ _C and the propagating light is emitted to the outside.

  As described above, in the condensing optical element of the first embodiment, the propagation / condensing function by the “wedge-shaped light guide” that uses the operating principle of the light guide plate used for the backlight or the like in reverse, Light incident on a large-area incident surface at a predetermined angle can be collected in the horizontal direction and emitted from a small-area emission end surface.

<Second Embodiment>
FIGS. 6A to 6D are schematic views showing the configuration of a condensing optical element according to the second embodiment of the present invention. 6A is a perspective view of the condensing optical element, FIG. 6B is a plan view of the condensing optical element as viewed from above, and FIG. 6C is an optical axis of the condensing optical element. FIG. FIG. 6D is an exploded perspective view when the condensing optical element is disassembled into two light guides.

As shown in FIGS. 6A to 6C, the condensing optical element 20 according to the second embodiment is the first except that the upstream reflective surface has a more complex polyhedral shape. The condensing optical element 10 according to the embodiment has substantially the same configuration, and includes an incident surface 22 having an incident portion on which light is incident, a first reflecting surface 24 facing the incident surface 22, the incident surface 22, and the first surface. 1 and the second reflection surface 26 ₁ and the third reflecting surface 26 ₂ to connect the two ends of the reflection surface 24, it is condensed light is configured to include an exit end face 28 of the emission part for emitting .

Further, as shown in FIG. 6D, the condensing optical element 20 includes a wedge-shaped light guide 20A disposed on the upstream side and a reverse wedge-shaped light guide 20B disposed on the downstream side. , And are formed integrally so as to be continuous through the transmission surface 23 which is a virtual surface. The first reflection surface 24 is bent with the transmission surface 23 as a boundary. On the light guide 20A side, the first reflecting surface 24 is divided into three planes 24 ₁ , 24 ₂ , and ₂ planes divided by line segments AB, BC, and CD connecting points A, B, C, and D. 24 ₃ is a polyhedral shape. Plane 24 _1, the plane 24 ₂ trapezoidal, plane 24 ₃ is triangular.

The thickness of the light guide 20A increases from the point A to the point B, and the thickness of the light guide 20A increases from the point B to the point C (or from the point B to the point D). Thus, each plane 24 _1, the plane 24 _2, planes 24 ₃ forms a normal is directed toward the center slope. Here, the center means a central portion having a symmetry axis of a condensing optical element formed substantially symmetrically along the light propagation direction. Plane 24 _1, the normal direction of the plane 24 _2, planes 24 ₃ are different each, three planes are arranged so as to intersect with each other.

As in the first embodiment, the light guide 20B side, the first reflecting surface 24 is composed of a single trapezoidal plane 24 _4, the thickness of the light guide body 20B at a constant is there. Further, the plane 24 ₁ , the plane 24 ₂ , the plane 24 _3, and the plane 24 ₄ are collectively referred to as the first reflecting surface 24 when it is not necessary to distinguish them.

In the condensing optical element 20, as in the first embodiment, the light incident from the incident portion onto the light guide 20 </ b> A at a predetermined angle is incident on the incident surface 22 and the first reflecting surface 24 (the plane 24 ₁ , the plane 24. ₂ , the plane 24 ₃ ), the second reflecting surface 26 _1, and the third reflecting surface 26 ₂ while being totally reflected. In the wedge-shaped light guide 20 </ b> A, the propagating light is converted from the higher-order mode to the lower-order mode, converted into parallel light, and passes through the transmission surface 23.

Light incident from the transparent surface 23 in the light guide 20B is the entrance surface 22, a first reflecting surface 24 (plane ₂₄ 4), the total reflection by the second reflecting surface 26 ₁ and the third between the reflective surface 26 ₂ Propagate while being. In the reverse wedge-shaped light guide 20B, the propagation light is converted from the low-order mode to the high-order mode and condensed in the horizontal direction. The light converted into the higher order mode and condensed toward the emission part is extracted from the emission end face 28 beyond the critical angle.

  The condensing optical element 20 according to the second embodiment is the same as that of the first embodiment having the planar first reflecting surface 14 in that the first reflecting surface 24 has a polyhedral shape. This is different from the condensing optical element 10. As shown in FIG. 8A, in the condensing optical element 10 of the first embodiment, the first reflecting surface 14 is flat, and the propagation characteristics of the light guide 10A change depending on the position where the light enters. do not do. Accordingly, the focal length does not change according to the position where the light is incident, and the condensed linear emission beam 42 is emitted from the linear incident beam 40.

On the other hand, as shown in FIG. 8B, in the condensing optical element 20 of the second embodiment, the first reflecting surface 24 of the light guide 20A has a polyhedral shape, and light is incident thereon. The propagation characteristics in the light guide 20A vary depending on the position. Accordingly, the focal length changes in accordance with the position where the light is incident, and the longitudinal incident beam 40 is vertically divided corresponding to each beam (beam 40 ₁ , beam 40 ₂ , beam 40 ₃ ) obtained by dividing the linear incident beam 40 into three in the horizontal direction. Three linear outgoing beams 42 (beam 42 ₁ , beam 42 ₂ , beam 42 ₃ ) arranged in the direction are emitted.

  By optimizing the shape of the reflecting surfaces of the two light guides of the condensing optical element, as shown in FIG. 8B, the incident beam 40 in the horizontal direction (horizontal direction or width direction) inferior in condensing property Can be divided to obtain an outgoing beam 42 in which the aspect ratio of the beam is reconstructed. Thereby, the condensing diameter of the outgoing beam 42 can be reduced. When reconstructing the emitted light in this way, the optical design of the condensing optical element becomes easier when the focal position is set near the connection point of the two light guides.

For example, by reconstructing the beam parameter product (BPP) of a multimode operation laser with poor beam quality in the slow axis direction, the light condensing property can be improved. Here, BPP is defined as the product of the beam waist radius ω ₀ and the full width at half maximum θ of the beam divergence angle. Also, in a multi-emitter one-dimensional LD array (so-called LD bar) having a plurality of light emitting points, the BPP can be reconfigured to improve the light condensing performance and to obtain a high output. . For example, in a linear laser beam such as slit light having a width of 10 mm and a height of 1 mm, the width direction corresponding to the vibration direction of the electric field is the slow axis direction, and the height direction is the fast axis direction.

  As described above, in the condensing optical element of the second embodiment, the light incident on the large-area incident surface at a predetermined angle in the horizontal direction by the propagation / condensing function by the “wedge-shaped light guide”. The light can be condensed and emitted from the emission end face having a small area. Further, by optimizing the polyhedral shape of the reflecting surface, it is possible to obtain an outgoing beam in which the propagation characteristic (focal length) is changed depending on the position where the light is incident, and the aspect ratio of the incident beam is reconfigured. That is, the condensing characteristic of the emitted light can be controlled. Thereby, the condensing diameter of an emitted beam can be made small.

(Modification of condensing optical element)
FIGS. 7A to 7C are schematic views showing a configuration of a modification of the condensing optical element according to the second embodiment of the present invention. FIG. 7A is a perspective view of the condensing optical element, FIG. 7B is a plan view of the condensing optical element as viewed from above, and FIG. 7C is an optical axis of the condensing optical element. FIG.

As shown in FIGS. 7A to 7C, the condensing optical element 30 according to the modification includes an incident surface 32 having an incident portion on which light is incident, and a first reflecting surface 34 facing the incident surface 32. (Plane 34 ₁ , Plane 34 ₂ , Plane 34 ₃ , and Plane 34 ₄ ), and the second reflecting surface 36 ₁ and the third reflecting surface 36 ₂ that connect both ends of the incident surface 32 and the first reflecting surface 34. And an emission end face 38 as an emission part from which the condensed light is emitted. The condensing optical element 30 includes a wedge-shaped light guide 30A disposed on the upstream side and a reverse wedge-shaped light guide 30B disposed on the downstream side via a transmission surface 33 that is a virtual surface. Are integrally formed so as to be continuous.

The reverse wedge-shaped light guide 30B on the downstream side opposes each other as the distance between the incident surface 32 and the first reflection surface 34 facing each other (the thickness of the light guide) decreases toward the downstream side. forming a down taper distance ₁ and the second reflecting surface 36 and the third reflecting surface 36 ₂ (width of the light guide) is reduced toward the downstream side. That is, the condensing optical element 30 is the light guide 30 </ b> B except that it forms a down taper in which both the width and the thickness of the light guide decrease toward the downstream side. The condensing optical element 20 has substantially the same configuration.

In the condensing optical element 30, as in the second embodiment, the light incident from the incident portion to the light guide 30 </ b> A at a predetermined angle is incident on the incident surface 32 and the first reflecting surface 34 (plane 34 ₁ , plane 34 _2, planes ₃₄ 3), it propagates while being totally reflected by the second reflecting surface 36 ₁ and the third between the reflective surface 36 _2. In the wedge-shaped light guide 30 </ b> A, the propagating light is converted from the higher-order mode to the lower-order mode, converted into parallel light, and passes through the transmission surface 33.

The light incident on the light guide member 30B from the transmitting surface 33, the incident surface 32, a first reflecting surface 34 (plane ₃₄ 4), the total reflection by the second reflecting surface 36 ₁ and the third between the reflective surface 36 ₂ Propagate while being. In the reverse wedge-shaped light guide 30B, the propagating light is converted from the low-order mode to the high-order mode and condensed in the horizontal direction and the vertical direction. The light converted to the higher order mode and condensed toward the emission part is extracted from the emission end face 38 beyond the critical angle.

  As described above, in the condensing optical element of the modified example, the light incident on the large-area incident surface at a predetermined angle is condensed by the propagation / condensing function by the “wedge-shaped light guide” to reduce the area. The light can be emitted from the emission end face. In particular, by forming a down taper in which both the thickness and width of the light guide body are reduced on the downstream side, the propagation light is condensed in the horizontal direction and the vertical direction, and the condensing property of the emitted light is improved. The emitted light can be extracted efficiently. Further, by optimizing the polyhedral shape of the reflecting surface, it is possible to obtain an outgoing beam in which the propagation characteristic (focal length) is changed depending on the position where the light is incident, and the aspect ratio of the incident beam is reconfigured. That is, the condensing characteristic of the emitted light can be controlled. Thereby, the condensing diameter of an emitted beam can be made small.

<Third Embodiment>
FIGS. 9A to 9D are schematic views showing the configuration of a condensing optical element according to the third embodiment of the present invention. 9A and 9B are perspective views of the condensing optical element, FIG. 9C is a plan view of the condensing optical element as viewed from above, and FIG. 9D is a condensing optical element. It is sectional drawing along the optical axis. FIG. 10 is an exploded perspective view when the condensing optical element is disassembled into two light guides.

  As shown in FIGS. 9A to 9D, the condensing optical element 50 according to the third embodiment is a sword-shaped light guide having a light propagation direction as a longitudinal direction. The condensing optical element 50 includes an incident surface 52 having an incident portion on which light is incident, and a reflecting surface 54 facing the incident surface 52. In the present embodiment, there is no surface corresponding to a so-called side surface, and both ends of the incident surface 52 and the reflecting surface 54 are directly connected.

  The incident part (not shown) is located at the upstream end of the incident surface 52 with respect to the light propagation direction, and the emitting part 58 is located at the downstream end (sword tip). In addition, although the case where the emission part 58 exists on the incident surface 52 is illustrated, in the condensing optical element 50 according to the third embodiment, a case where the emission part 58 exists on the reflection surface 54 is also assumed.

In the present embodiment, the incident surface 52 is bent with a line segment IJ as a boundary, and is composed of an upstream rectangular plane and a downstream triangular plane. The reflecting surface 54 has a shape like a ship bottom, and is divided into three planes 54 ₁ , planes 54 ₂ , 3 divided by line segments EG, FG, GH connecting points E, F, G, H. It is configured polyhedral shape by a plane 54 _3. Plane 54 ₁ is triangular, flat 24 _2, planes 24 ₃ are rhombus-shaped. Each plane 54 _1, plane _542, and plane ₅₄₃ forms a normal is directed toward the center slope. The normal directions of the three planes are different from each other, and the plurality of planes are arranged to intersect each other. The plane 54 ₁ , the plane 54 ₂ , and the plane 54 ₃ are collectively referred to as the reflecting surface 54 when it is not necessary to distinguish them.

  The condensing optical element 50 includes a wedge-shaped light guide 50A disposed on the upstream side and a reverse wedge-shaped light guide 50B disposed on the downstream side via a transmission surface 53 that is a virtual surface. Are integrally formed so as to be continuous. The transmission surface 53 is a triangular plane having vertices at points G, I, and J. As in the other embodiments, the shape forming the taper is referred to as a “wedge shape”. However, the light guide 50A is a quadrangular pyramid with the point G at the apex, and the light guide 50B is the point H. Is a triangular pyramid.

In the light guide 50A, the width of the light guide is constant, but the distance between the light incident surface 52 and the reflective surface 54 (thickness of the light guide) increases toward the downstream side. Forming. That is, the thickness of the light guide 50A increases from the point E to the point G (or from the point F to the point G). The light guide 50A side, the incident surface 52, the plane 54 ₁ is a reflective surface, confining light in the four sides of the plane _542, and plane 54 _3.

On the other hand, in the light guide 50B, the distance between the incident surface 52 and the reflection surface 54 facing each other (the thickness of the light guide) decreases toward the downstream side, and the width of the light guide toward the downstream side. A decreasing down taper is formed. That is, the thickness of the light guide 50B decreases from the point I to the point H (or from the point J to the point H). The light guide 50B side, confining light in three surfaces of the incident surface 52, a plane ₅₄₂ and plane ₅₄₃ is a reflective surface. Plane ₅₄₂ and plane ₅₄₃ is provided over the light guide 50A and the light guide 50B.

In the condensing optical element 50, as in the first embodiment, the light incident on the light guide 50A from the incident portion at a predetermined angle is incident on the incident surface 52 and the reflecting surface 54 (the plane 54 ₁ , the plane 54 ₂ , the plane 54 ₃ ) while being totally reflected. In the wedge-shaped light guide 50A, light propagation is converted from higher order mode to the low-order mode while being collimated, inclined planes 54 _2, are condensed in the center direction by the plane _543, the transmission surface Pass through 53.

The light that has entered the light guide 50B from the transmission surface 53 propagates while being totally reflected between the incident surface 52 and the reflection surface 54 (the flat surface 54 ₂ and the flat surface 54 ₃ ). In the reverse wedge-shaped light guide 50B, the propagating light is converted from the low-order mode to the high-order mode and condensed in the horizontal direction and the vertical direction. The light converted to the higher order mode and condensed toward the emission part is extracted from the emission part 58 beyond the critical angle.

  As described above, the condensing optical element of the third embodiment condenses light incident at a predetermined angle on a large area incident surface by the propagation / condensing function of the “wedge-shaped light guide”. Thus, the light can be emitted from the emission end face having a small area. In particular, by forming a down taper in which both the thickness and width of the light guide body are reduced on the downstream side, the propagation light is condensed in the horizontal direction and the vertical direction, and the condensing property of the emitted light is improved. The emitted light can be extracted efficiently. Further, by forming a reflecting surface composed of a pair of steeply inclined planes from the upstream side to the downstream side, the light collecting property in the central direction is further improved.

  Further, by optimizing the polyhedral shape of the reflecting surface, it is possible to obtain an outgoing beam in which the propagation characteristic (focal length) is changed depending on the position where the light is incident, and the aspect ratio of the incident beam is reconfigured. That is, the condensing characteristic of the emitted light can be controlled. Thereby, the condensing diameter of an emitted beam can be made small.

(Modification of condensing optical element)
11 and 12 are schematic views showing the configuration of a modification of the condensing optical element according to the third embodiment of the present invention. 12A and 12B are perspective views of the condensing optical element, FIG. 12C is a plan view of the condensing optical element viewed from above, and FIG. 12D is a condensing optical element. It is sectional drawing along the optical axis. As shown in FIG. 11, the condensing optical element according to the modification includes the sword-shaped condensing optical element 50 according to the third embodiment in the vertical direction (from the front of the drawing) along the cutting lines 55 and 57. It has a shape that is cut in the direction toward the back, the vertical direction).

  As shown in FIGS. 12A to 12D, the condensing optical element 60 according to the modification includes an incident surface 62 having an incident portion on which light is incident, and a reflecting surface 64 facing the incident surface 62. Configured. Both ends of the incident surface 62 and the reflecting surface 64 are directly connected. In addition, with respect to the light propagation direction, the incident portion (not shown) is located at the upstream end portion of the incident surface 62, and the emission portion 68 is located at the downstream end portion (sword tip).

In the present embodiment, the incident surface 62 is bent with a line segment IJ as a boundary, and is composed of an upstream trapezoidal plane and a downstream triangular plane. The reflecting surface 64 has a shape like a ship bottom, and line segments KM, LN, MI, NJ, MG, NG, connecting points G, H, I, J, K, L, M, and N, five planes 64 ₁ which is 5 divided by GH, plane 64 _2, planes 64 _3, plane 64 _4, a polyhedral shape by a plane 64 _5. The plane 64 ₁ is a pentagon, the plane 64 ₂ and the plane 64 ₃ are triangles, and the plane 64 ₄ and the plane 64 ₅ are quadrangles. The normal directions of the five planes are different from each other, and the plurality of planes are arranged to intersect each other. The plane 64 ₁ , the plane 64 ₂ , the plane 64 ₃ , the plane 64 ₄ , and the plane 64 ₅ are collectively referred to as the reflective surface 64 when it is not necessary to distinguish them.

  The condensing optical element 60 includes a wedge-shaped light guide 60A disposed on the upstream side and a reverse wedge-shaped light guide 60B disposed on the downstream side via a transmission surface 63 that is a virtual surface. Are integrally formed so as to be continuous. The transmission surface 63 is a triangular plane having vertices at points G, I, and J.

In the present embodiment, in the light guide 60A, the width of the light guide increases toward the downstream side, and the interval between the incident surface 62 and the reflective surface 64 facing each other (the thickness of the light guide) is An up taper that increases toward the downstream side is formed. That is, the width of the light guide 60A increases from the point K to the point I (or from the point L to the point J). Further, the thickness of the light guide 60A increases from point L → point N → point G (or point K → point M → point G). The light guide 60A side, the incident surface 62, the plane 64 ₁ is a reflective surface, a plane 64 _2, planes 64 _3, confining light in six sides of the plane 64 _4, and the plane 64 _5.

On the other hand, like the light guide 50B according to the third embodiment, the light guide 60B forms a down taper in which both the thickness and the width of the light guide decrease toward the downstream side. The light guide 60B side, confining light in three surfaces of the incident surface 62, the plane 64 ₄ is a reflecting surface, and the plane 64 _5. Plane 64 ₂ and the plane 64 ₃ is provided over the light guide 60A and the light guide 60B. That is, the condensing optical element 60 according to the modification has the same structure as the condensing optical element 50 according to the third embodiment, except that the side portion of the upstream light guide is cut and the taper shape is complicated. It is.

In the condensing optical element 60, as in the first embodiment, the light incident from the incident portion to the light guide 60A at a predetermined angle is incident on the incident surface 62 and the reflecting surface 64 (the plane 64 ₁ , the plane 64 ₂ , the plane 64 ₃ , the plane 64 ₄ , and the plane 64 ₅ ) while being totally reflected. In the wedge-shaped light guide 60A, the propagating light is converted from the higher-order mode to the lower-order mode, and is condensed in the center direction by the inclined plane 64 ₁ , plane 64 ₂ , plane 64 ₃ , plane 64 ₄ , and plane 64 _5. Then, it passes through the transmission surface 63.

The light that has entered the light guide body 60B from the transmission surface 63 propagates while being totally reflected between the incident surface 62 and the reflection surface 64 (plane 64 ₂ , plane 64 ₃ ). In the reverse wedge-shaped light guide 60B, the propagating light is converted from the low-order mode to the high-order mode and condensed in the horizontal direction and the vertical direction. The light converted to the higher order mode and condensed toward the emission part is extracted from the emission part 68 beyond the critical angle.

  As described above, in the condensing optical element of the modified example, the light incident on the large-area incident surface at a predetermined angle is condensed by the propagation / condensing function by the “wedge-shaped light guide” to reduce the area. The light can be emitted from the emission end face. In particular, by forming a down taper in which both the thickness and width of the light guide body are reduced on the downstream side, the propagation light is condensed in the horizontal direction and the vertical direction, and the condensing property of the emitted light is improved. The emitted light can be extracted efficiently. Further, by forming a reflecting surface composed of a pair of steeply inclined planes from the upstream side to the downstream side, the light collecting property in the central direction is further improved.

  Further, by optimizing the polyhedral shape of the reflecting surface, it is possible to obtain an outgoing beam in which the propagation characteristic (focal length) is changed depending on the position where the light is incident, and the aspect ratio of the incident beam is reconfigured. That is, the condensing characteristic of the emitted light can be controlled. Thereby, the condensing diameter of an emitted beam can be made small. In particular, in this modification, it is further easy to optimize the polyhedral shape of the reflecting surface by configuring the reflecting surface from five planes.

<Fourth embodiment>
FIG. 14A is a schematic perspective view showing a configuration of a condensing optical element according to the fourth embodiment of the present invention, and FIG. 14B is an exploded view of this condensing optical element into two light guides. FIG. FIG. 13 is a schematic perspective view showing an example of a method of forming a light guide body on the upstream side of the condensing optical element shown in FIG.

As shown in FIG. 14A, the condensing optical element 80 according to the fifth embodiment is a long light guide with the light propagation direction as the longitudinal direction. The condensing optical element 80 includes an incident surface 82 having an incident portion on which light is incident, a first reflecting surface 84 facing the incident surface 82, and a first connecting surface of the incident surface 82 and the first reflecting surface 84. and second reflecting surfaces 86 ₁ and the third reflecting surface _862, is condensed light is configured to include an exit end face 88 of the emission part for emitting.

In this embodiment, the second reflecting surface 86 ₁ and the third reflecting surface ₈₆₂ constitutes a opposing side surface of the light guide plate. The incident portion (not shown) is located at the upstream end of the incident surface 82. An emission end face 88 that is an emission part is formed at the distal end portion on the downstream side. The exit end face 88 is formed to form a predetermined angle (about 90 ° in the drawing) with respect to the entrance face 82 so that the propagating light exits beyond the critical angle.

14B, the condensing optical element 80 includes a wedge-shaped light guide 80A disposed on the upstream side and a reverse wedge-shaped light guide 80B disposed on the downstream side. In addition, they are integrally formed so as to be continuous through a transmission surface 83 which is a virtual surface. The incident surface 82 is composed of one plane. The transmission surface 83 is a surface including a conical axis of symmetry which will be described later (see FIG. 13). The first reflecting surface 84, the light guide 80A side consists of a single curved surface 84c, the light guide 80B side, the two planes 84 _1, and a flat 84 _2. Plane 84 _1, the plane 84 ₂ is trapezoidal. Plane 84 _1, the plane 84 ₂ forms a normal is directed toward the center slope. That is, the first reflecting surface 84 is a curved surface 84c, the plane 84 ₁ which cross each other, is constituted by a plane 84 ₂ to polyhedral shape. Each curved surface 84c, plane 84 _1, the plane 84 _2, when it is not necessary to distinguish, collectively referred to as a first reflecting surface 84.

  80 A of light guides are equipped with the structure which cut out a part of cone along the symmetry axis. A structure 70 corresponding to the light guide 80A will be described with reference to FIG. The structure 70 includes a structure in which a part of the cone 75 is cut out in a “wedge shape” along the axis of symmetry 77 as illustrated by an auxiliary line (dashed line).

That is, the structure body 70 is connected to the front surface 72 (incident surface 82) having an incident portion on which light is incident, the rear surface 74 (first reflective surface 84) facing the front surface 72, and both ends of the front surface 72 and the rear surface 74. And a side surface 76 ₁ (second reflection surface 86 ₁ ) and side surface 76 ₂ (third reflection surface 86 ₂ ), and an emission end surface 78 (output end surface 88) as an emission part from which light is emitted. Yes. The incident portion (not shown) is located at the upstream end of the surface 72. The back surface 74 is formed by cutting out the side surface of the cone 75 and is formed in a curved surface convex outward. The emission end face 78 is an end face cut out along the symmetry axis 77 so as to include the symmetry axis 77 of the cone 75. As described in parentheses, each part of the structure 70 corresponds to each part of the light guide 80A.

Wedge-shaped light guide 80A, a second distance between the reflecting surface 86 ₁ and the third reflecting surface 86 ₂ of the (width of the light guide) is constant, which are opposite to each other, the incident surface 82 opposite to each other An up taper is formed in which the distance from the first reflecting surface 84 (the thickness of the light guide) increases toward the downstream side. The light guide 80A side, the entrance surface 82, a first reflecting surface 84 (curved surface 84c), confining the light in the second 4 surface of reflecting surface _861, and a third reflecting surface 86 _2.

Reverse wedge-shaped light guide body 80B includes a second reflecting surface 86 ₁ facing each other with a third distance between the reflecting surface ₈₆₂ of the (width of the light guide) is reduced toward the downstream side, facing each other The distance between the incident surface 82 and the first reflecting surface 84 (the thickness of the light guide) forms a down taper that decreases toward the downstream side. The light guide 80B side, the entrance surface 82, a first reflecting surface 84 (plane 84 _1, the plane ₈₄ 2), confining the light by the second reflecting surface 86 _1, and the third 5 side of the reflecting surface ₈₆₂ of the ing.

In the condensing optical element 80, as in the first embodiment, the light incident on the light guide 80A from the incident portion at a predetermined angle is incident on the incident surface 82, the first reflecting surface 84 (curved surface 84c), and the second. It propagates while being totally reflected between the reflecting surface _861, and a third reflecting surface 86 ₂ of the. In the wedge-shaped light guide 80 </ b> A, the propagating light is converted from the higher-order mode to the lower-order mode, collected in the central direction by the curved surface 84 c that protrudes outward, and passes through the transmission surface 83. The curved surface 84c is a part of the side surface of the cone. Thus, the curved surface 84c obtained by rotating a straight line or a curve around the rotation axis has a high light collecting property in the central direction including the rotation axis.

The light incident on the light guide 80B from the transmission surface 83 is incident surface 82, first reflection surface 84 (plane 84 ₁ , plane 84 ₂ ), second reflection surface 86 ₁ , and third reflection surface 86 _2. It propagates while being totally reflected between. In the reverse wedge-shaped light guide 80B, the propagating light is converted from the low-order mode to the high-order mode, and condensed in the horizontal direction and the vertical direction. The light converted to the higher order mode and condensed toward the emission part is extracted from the emission part 88 beyond the critical angle.

  As described above, the condensing optical element of the fourth embodiment condenses light incident at a predetermined angle on a large-area incident surface by the propagation / condensing function of the “wedge-shaped light guide”. Thus, the light can be emitted from the emission end face having a small area. In particular, by forming a down taper in which both the thickness and width of the light guide body are reduced on the downstream side, the propagation light is condensed in the horizontal direction and the vertical direction, and the condensing property of the emitted light is improved. The emitted light can be extracted efficiently. Further, by forming a reflecting surface made of a curved surface obtained by cutting a part of the side surface of the cone on the upstream side, the light condensing property in the central direction is further improved.

  Further, by optimizing the polyhedral shape of the reflecting surface, it is possible to obtain an outgoing beam in which the propagation characteristic (focal length) is changed depending on the position where the light is incident, and the aspect ratio of the incident beam is reconfigured. That is, the condensing characteristic of the emitted light can be controlled. Thereby, the condensing diameter of an emitted beam can be made small.

(Modification of condensing optical element)
FIGS. 15A to 15C are diagrams showing modifications of the condensing optical element according to the fourth embodiment. In the fourth embodiment, the condensing optical element having a reflecting surface made of a curved surface obtained by cutting out a part of the side surface of the cone has been described. However, the concentrating optical element is not limited to a simple cone, and rotates a straight line or a curve around the rotation axis. It is sufficient that the shape is symmetrical with respect to the rotation axis obtained as described above, and a curved surface obtained by cutting the side surface (slope) can be used as the reflecting surface. A condensing optical element having such a curved surface as a reflecting surface has high condensing properties in the central direction including the rotation axis, like the condensing optical element 80 of the fourth embodiment.

  First, as shown in FIG. 15A, the condensing optical element according to the fourth embodiment uses a curved surface obtained by rotating a straight line 92 around a rotation axis 90 as a reflecting surface. . In addition to this, as shown in FIG. 15B, a curved surface obtained by rotating an outwardly convex curve 94 around the rotation axis 90 (lower side in the drawing) can be used as the reflecting surface. As shown in FIG. 15C, a curved surface obtained by rotating a curved line 96 that protrudes inward (upward in the drawing) around the rotation axis 90 can be used as the reflecting surface.

<Modification>
In the above-described embodiment, the example of the condensing optical element formed substantially symmetrically along the light propagation direction has been described. However, the condensing optical element is not limited to a symmetrical shape. Moreover, the condensing optical element of various shapes can be obtained by the combination method of two light guides. 5A to 5D are diagrams illustrating an example of a method of combining two light guides. The example of the condensing optical element 10 according to the first embodiment will be described. As described above, the condensing optical element 10 is formed by combining the wedge-shaped light guide 10A and the reverse wedge-shaped light guide 10B. Integrated.

  In the first embodiment, as illustrated in FIG. 5A, the light guide 10 </ b> A and the light guide 10 </ b> B are joined by the transmission surface 13 and are arranged in substantially the same plane. However, the combination method of the light guide 10A and the light guide 10B is not limited to this form. By various combination methods, the optical path of propagating light can be changed and emitted in an arbitrary direction. Further, the condensing optical element can be reduced in size by bending the optical path of the propagating light.

For example, FIG. 5 (B), the between the light guide 10A and the light guide 10B, cross section can sandwich the third light guide plate 19 _first transmitting surface 13. By increasing the distance between the incident part and the emission part, light can be emitted further away.

Further, as shown in FIG. 5 (C), it can be between the light guide 10A and the light guide 10B, sandwiching the first reflecting member 19 ₂ provided with a reflecting surface that is obliquely cut 45 ° . The optical path of the light incident from the light guide 10 </ _b > A is bent 90 ° by the first reflecting member 192. Thereby, the optical path of the light radiate | emitted from the light guide 10B can be bent 90 degrees from the form of FIG. 5 (A). Further, the light converging optical element 10 is downsized by bending the optical path.

Further, as shown in FIG. 5 (D), between the light guide 10A and the light guide 10B, second reflecting member 19, _second and third reflection having a reflective surface that is obliquely cut 45 ° You can sandwich the member 19 _3. An optical path of light incident from the light guide 10A, a second reflecting member 19 ₃ by bending 90 °, bent 90 ° more in the third reflecting member 19 _3. Thereby, the optical path of the light radiate | emitted from the light guide 10B can be bent 180 degrees from the form of FIG. 5 (A). Further, the light converging optical element 10 is downsized by bending the optical path.

  Even in the combinations shown in FIGS. 5A to 5D, the emitted light from the emission end face 18 is condensed by the condenser lens 17 disposed outside, and the condensed light is irradiated onto the object. Can do. In addition to condensing with an externally arranged lens, the exit end face 18 may be directly processed to form a lens on the surface, and an optical fiber is directly connected to the exit end face 18 so that the outgoing light is connected to the optical fiber. You may lead.

DESCRIPTION OF SYMBOLS 10 Condensing optical element 10A Light guide 10B Light guide 12 Incident surface 13 Transmission surface 14 1st reflective surface 15 LD array 16 _1st reflective surface 16 ₂ 3rd reflective surface 17 Condensing lens 18 Outgoing end surface 19 ₁ light guide plate 19 ₂ reflection member 19 ₃ reflection member 20 condensing optical element 20A light guide 20B light guide 21 sunlight 22 incident surface 23 transmission surface 24 first reflection surface 26 ₁ second reflection surface 26 ₂ third Reflective surface 28 Emission end surface 30 Condensing optical element 30A Light guide 30B Light guide 32 Incident surface 33 Transmission surface 34 First reflection surface 36 ₁ Second reflection surface 36 ₂ Third reflection surface 38 Output end surface 40 Incident Beam 42 Outgoing beam 50 Condensing optical element 50A Light guide 50B Light guide 52 Incident surface 53 Transmitting surface 54 Reflecting surfaces 55, 57 Cutting line 58 Output unit 60 Condensing optical element 60A Light guide 60B Light guide 62 Incident surface 63 Transmission surface 4 reflecting surface 70 focusing optic 72 surface 74 rear surface 75 cone 77 axis of symmetry 78 exit end face 80 focusing optic 80A light guide 80B light guide 82 entrance surface 83 transmitting surface 84 first reflecting surface 86 ₁ second Reflective surface 86 ₂ Third reflective surface 88 Output end surface 90 Rotating shaft 92 Straight line 94 Curve 96 Curve

Claims (2)

An incident surface having an incident portion on which a plurality of lights are incident at a predetermined incident angle; and at least one reflecting surface facing the incident surface; and the light incident from the incident surface is the incident surface and the incident surface. A long light guide that is totally reflected and propagates in the length direction with respect to the reflecting surface facing the light source, wherein at least one of the thickness of the light guide and the width of the light guide is in the light propagation direction. A first light guide that increases toward the downstream side;
A surface continuous with the incident surface, at least one reflecting surface facing the surface, and an emitting portion for emitting light that is totally reflected and propagated between the surface and the reflecting surface facing the surface; An elongate light guide coupled to the first light guide so as to form an optical path with the first light guide, wherein at least the thickness of the light guide and the width of the light guide A second light guide body, one of which decreases toward the downstream side in the light propagation direction;
Including
The reflection surface opposite to the incident surface and the reflection surface opposite to the surface are different so that the emission position or emission direction of the light emitted from the emission portion differs according to the position in the width direction where the light of the incidence portion is incident. A condensing optical element comprising at least one of a plurality of planes whose normals are inclined in the central direction and intersect each other.   2. The condensing optical element according to claim 1, wherein the exit portion is an exit end face that intersects the surface at an angle at which the propagated light exits beyond a critical angle.

Images