JP2007264330A - Parallel beam-generating photoconductor for lighting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoconductor for lighting that mixes light beams from a plurality of light sources, making a uniform brightness and a color tone and sending out as parallel light beams or intended diffuse, condensing light beams. <P>SOLUTION: (1) A lens is provided on the incident face and the exiting face of the photoconductor, with these incident face lens and the exiting face lens set to essentially share a focal point. (2) In the middle between the first photoconductor having the incident face lens and the second photoconductor having the exiting face lens, there is provided a space that can increase/decrease a relative distance between the first and second photoconductors. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention (hereinafter referred to as the present invention) mixes light emitted from a light source such as an LED array composed of a plurality of LEDs, and forms a plate-like parallel plate such as a flat plate, a cylindrical wall, or a truncated cone wall. The present invention relates to a light guide with a lens, such as a confocal (afocal) lens system, which is formed into a beam (light beam group) and irradiates a target narrow region at a desired irradiation angle. Further, these light guides with lenses are provided with means for converting parallel light into intentional divergence, divergence having a concentration angle, and concentrated light (wedge-shaped light group), and irradiate a slightly wide predetermined area range, or It also relates to a light guide for converging once and then diverging. In addition, for example, a quadrangular pyramid zoom illuminating device is proposed in which a plurality of flat light guides are interlocked by a bevel gear, a flexible shaft, and the like, and the tilt angle is controlled to a simultaneous operation state.

Here, some meanings and definitions of important terms used throughout the specification of the present invention will be explained.
The term “light source” is not limited to LEDs (light emitting diodes), but generates light suitable for illumination, such as halogen lamps, incandescent bulbs, cold cathode fluorescent lamps (CCFL), discharge lamps (discharge lamps), etc. It means any light source and can be used in the same way as an LED.
The term “light beam” is not limited to the visible light region of 380 nm to 780 nm, and includes ultraviolet rays, infrared rays, and the like.
The term “lens” includes not only spherical lenses but also aspherical lenses, as well as cylindrical lenses, ring-shaped cylindrical lenses (toroidal lenses), and these lens surfaces corresponding to aspherical lenses for spherical lenses. As described above, a modified lens is also included. For all of these, not only convex lenses but also concave lenses may be used as necessary. In addition to a simple lens shape, a Fresnel lens, a diffractive lens, or the like may be used.
The term “refractive index” means, as a typical value, a relative refractive index with respect to air of a material for a light beam (d-line) having a wavelength of about 589 nm, unless otherwise specified.
The term “reflecting surface” means a totally reflecting surface or a mirror-finished surface.
The term “light distribution characteristic” means an illumination light amount distribution for each solid angle direction, and is the same as or similar to the content expressed as directivity characteristic, viewing angle, etc. in catalogs such as LEDs. With regard to LEDs, proposals for establishing a uniform measurement method for light distribution characteristics as soon as possible have been issued from various directions.
Further, throughout the specification of the present invention, the same symbols are used in the drawings to indicate the same kind of contents.

The present inventors previously filed an application for an optical member using an afocal lens system as the name of the invention: “light control device (beam expander)” in Japanese Patent Application No. 2004-300230.

Further, in Japanese Patent Application No. 2005-259053, an application was filed for an optical member using a cylindrical lens system or the like as the title of the invention: “light guide device for linear illumination”. The entire text of these specifications is referred to / cited here as related literature materials, and repeated detailed description of the same contents is omitted for the sake of brevity.

  Conventionally, in an LED illumination light source device (called machine vision system) for a CCD for image analysis or a CMOS camera (referred to as a machine vision system), in order to clearly observe a target object, When illuminating a range or illuminating a frustoconical range, a number of so-called collimated LEDs with a very narrow viewing angle are arranged in a row, with the LED's light-emitting part arranged at the focal position of the lens. It was common to do.

  In the prior art method as described above, it is merely an arrangement of independent straight light beam groups, and if the arrangement interval of the LEDs is wide, the irradiation range of each light source is narrow. When these light sources are used in combination, it is difficult to achieve good color mixing (color mixing). The present invention has been devised to solve these problems.

The illumination light guide for generating a parallel beam according to the present invention has the following configuration as means for solving the above problems.
This illumination light guide is composed of lenses formed on the light incident surface and the light exit surface of one light guide, respectively, and the light entrance surface lens and the light exit surface lens substantially share the focal position.

  As yet another means, the illumination light guide of the present invention comprises a plurality of light guides, and is intermediate between a first light guide having a light incident surface lens and a second light guide having a light exit surface lens. In addition, there is a space in which the relative distance between the first light guide and the second light guide can be increased and decreased, and the entrance surface lens and the exit surface lens substantially share the focal position within the relative distance adjustment range. It may be arranged to do.

  Each of the illumination light guides is formed such that the radius of curvature of the entrance surface lens is smaller than the radius of curvature of the exit surface lens.

  The illumination light guide described above is formed such that the aperture width of the entrance surface lens is smaller than the aperture width of the exit surface lens, and the aperture end of the entrance surface lens and the exit end of the exit surface lens are smooth flat surfaces or curved surfaces, respectively. It is connected by the side formed.

  In the illumination light guide, the numerical aperture of the entrance surface lens is larger than the numerical aperture of the exit surface lens.

  The illumination light guide is formed in a thin plate shape, and an entrance surface lens is formed on one surface in the short side direction and an exit surface lens is formed on the other surface, but the light guide is formed in a truncated cone shape. In some cases, the entrance surface lens is formed on the top surface, and the exit surface lens is formed on the bottom surface.

  The illumination light guide described above is configured such that the light guide can be rotated about its longitudinal axis, and two or more illumination light guides having such a configuration are connected by appropriate rotation link means. Thus, the light from the light source can be irradiated at the same inclination angle.

  The illumination light guide described above may be formed in a so-called ring shape in which a side surface connecting a light incident surface lens and an output surface lens is formed in a curved shape. One light guide may be formed in a ring shape, or each light guide may be formed into one ring shape by combining a plurality of light guides formed in a substantially fan shape.

  The above-mentioned illumination light guide is provided with a bent portion between a part of the light guide, more specifically between the entrance surface lens and the exit surface lens, and the light entering from the entrance surface is reflected by the inside of the side surface portion of the light guide. Then, after changing the traveling direction (light), the light may be formed so as to exit from the exit surface.

  You may make it include a reflective surface in at least one part of said light guide for illumination. In order to scatter light, ultra-small hollow beads or porous beads, fillers and the like are arranged on the reflecting surface.

  According to the means for solving the problems described in claims 1 and 6, in the present invention, the light guide is formed in a so-called cylindrical lens shape, specifically, a thin plate shape or a truncated cone shape, and one end in the short direction thereof. Since the incident surface lens is provided on the surface and the exit surface lens is provided on the opposite side, the light incident on the light guide from the light source is reflected at various angles inside the light guide and mixed violently. The light emitted from the plurality of light sources can be mixed with each other inside the light guide. As a result, even when the arrangement interval of the LEDs of the light source is wide, there is no difference in brightness in the portion of the irradiation light from the exit lens, and a linear irradiation light beam that is nearly uniform is obtained, and when using a combination of light sources of multiple colors However, good color mixing (color mixing) can be realized.

  Moreover, according to the solution means described in claim 2, when constituted by a plurality of light guides, between the first light guide having the entrance surface lens and the second light guide having the exit surface lens. A space in which the relative distance between the first light guide and the second light guide can be increased or decreased, and the entrance surface lens and the exit surface lens substantially share the focal position within the relative distance adjustment range. As a result, it is possible to obtain an almost ideal plate-shaped irradiation light, and by using the relative distance adjusting means between the first light guide and the second light guide, strong concentrated light at a close distance position is obtained. In addition to obtaining a diffused light beam in a narrow angle range, it is possible to finely adjust the traveling state of the light beam so that it is once condensed and then diffused. In addition, since the focal positions of the entrance surface lens and the exit surface lens are arranged in a space outside the light guide, it is possible to avoid a high temperature of the light guide due to vortex concentration of light inside the light guide. Therefore, it is possible to form the light guide with an inexpensive and light material such as resin other than glass.

  According to the solution of the third aspect, the present invention is such that the radius of curvature of the entrance surface lens of the light guide is smaller than the radius of curvature of the exit surface lens, and the entrance surface lens and the exit surface lens are substantially formed. Since it is formed so as to share the focal position, light incident on the light guide from the light source can be sent out from the exit surface lens as parallel light.

  According to the solution of the fourth aspect, the present invention forms the opening width of the entrance surface lens of the light guide smaller than the opening width of the exit surface lens, and the entrance surface lens and the exit surface lens are substantially formed. Since it is formed so as to share the focal position, light incident on the light guide from the light source can be sent out from the exit surface lens as parallel light.

  According to the solution of the fifth aspect of the present invention, since the numerical aperture of the entrance surface lens of the light guide is larger than the numerical aperture of the exit surface lens, the present invention makes light guide light incident from the light source. In doing so, light from a wide angle can be introduced into the light guide. This eliminates the need for precise alignment of the light path between the light source and the light guide, thus simplifying the assembly of the light guide. Also, even if the light source is inadvertently shifted due to something hitting it during use, it can be used as it is because the angle at which light can enter the light guide is wide.

  According to the solution means of Claim 7, the light guide for illumination of this invention is set as the structure which a light guide can rotate centering | focusing on a longitudinal direction axis | shaft, and several light guides of such a structure Are connected by an appropriate rotation link means so that light can be irradiated at the same inclination angle. Thereby, the irradiation angle of the light emitted from the light guide can be arbitrarily changed, and the position of the collection point of the irradiation light can be changed by zooming.

  According to the solution of the ninth aspect of the present invention, the present invention provides a part of the light guide, more specifically, a bent portion between the entrance surface lens and the exit surface lens, and at least a part of the light guide. If the reflecting surface is included, the light entering from the incident surface hits the inner side of the side surface portion of the light guide and reflects (changes the traveling direction of light), and then the light comes out from the emitting surface. As a result, the height of the light guide (the length in the short direction) can be made shorter than that without a bent portion, so the light guide itself, and thus the lighting fixture using this light guide, can be compact. It is possible to configure. Further, depending on the angle of the bent portion, the irradiation object can be illuminated from the lateral direction. As a comparison, in order to irradiate a target object from a lateral direction with a light guide having a configuration not provided with a bent portion, a light source is disposed beside the target object, and a lighting apparatus using such a light guide Has a limitation on space and wiring in arranging the light source and the light guide, and cannot be formed into a desired shape. In addition, depending on the type of light source, the light source portion generates heat and becomes high temperature, and if the irradiation target point is close to the light source, there is a possibility that the irradiation target may be altered by heat, so that the usage application is limited. However, the present invention has solved these problems.

  Further, according to the solution of the present invention, since the light guide includes a reflective surface on which hollow beads or the like are arranged, the light incident on the light guide hits the reflective surface. Since the light is reflected at an appropriate angle, an ideal light mixing state can be obtained, and the light emitted from the light guide exit surface lens portion becomes substantially uniform.

  It will be described using a specific example, but it does not limit the scope of this patent, and unless it violates the purpose described in the claims, all of its uses, contents of construction, etc. are variously modified based on known techniques. , Substitutions, combinations, applications, and their results are also included within the scope of this patent.

As shown in the cross-sectional views of FIGS. 1 to 4, a single light guide 10 includes a lens 13 on each of the incident surface 10 </ b> A and the exit surface 10 </ b> B, and the lens 13 on the entrance surface 10 </ b> A and the lens on the exit surface 10 </ b> B. When the light guide for illumination designed so as to substantially share the focal point F is used, the light emitted from the LED light source 11 can be processed into parallel rays and sent out. Moreover, as shown in FIGS. 2 and 3, the radius of curvature R1 of the lens 13 of the incident surface 10A, well when smaller than the radius of curvature R ₂ of the lens 13 of the exit surface 10B, further, the opening width of the incident surface lens H1 2 is smaller than the aperture width H2 of the lens on the exit surface 10B, and the aperture end of the lens 13 on the entrance surface 10A and the aperture end of the lens 13 on the exit surface 10B are respectively smooth as shown in FIG. 3 or a smooth curved surface (in this case, a cylindrical surface) 17 as shown in FIG. 3, and the numerical aperture NA1 of the lens 13 on the entrance surface 10A is larger than the numerical aperture NA2 of the lens 13 on the exit surface 10B. Larger is better.

As a specific example satisfying these conditions, for example, in FIG. 2, MMA resin (methyl methacrylic resin), refractive index N = 1.492 is used as a material,
The radius of curvature R1 of the lens of the entrance surface 10A = 3 mm,
The aperture width H1 of the lens on the entrance surface 10A = 3 mm,
The numerical aperture NA1 of the lens on the entrance surface 10A = about 20 °
The radius of curvature R2 of the lens on the exit surface 10B is 8 mm,
The opening width H2 of the lens on the exit surface 10B = 6 mm,
The numerical aperture NA2 of the lens on the exit surface 10B = about 15 °
The width W of the light guide 10 is 33 mm.
And good.
In this case, as described in detail in the title of the invention “light guide device for linear illumination” previously filed in Japanese Patent Application No. 2005-259053 by the present inventors,
The focal length f1 of the lens 13 on the incident surface 10A is f1 = N · R1 / (N−1) = about 3R1 = 9 mm.
The focal length f2 of the lens 13 on the exit surface 10B is f2 = N · R2 / (N−1) = about 3R2 = 24 mm.
Accordingly, the calculation is W = f1 + f2 = about 9 mm + about 24 mm = about 33 mm.
In this way, the lens of the entrance surface 10A and the lens of the exit surface 10B substantially share the focal position, that is, an afocal optical system is established, and light incident in parallel is sent out in parallel. I was able to.

Next, when the radius of curvature R1 of the lens of the entrance surface 10A is made smaller than the radius of curvature R2 of the lens of the exit surface 10B, as is apparent from FIG. Even when the focal point F1 is connected to the outside, when viewed from the lens side of the exit surface 10B, the focal distance f2 of the lens on the exit surface 10B is larger than f1, and thus the relative axis misalignment angle of the focus f1 becomes small. There is a relationship in which light closer to parallel rays can be sent out from the lens side of the exit surface 10B. The ratio of R2 / R1 that can effectively obtain this effect is preferably in the range of 1.1 to 10. The reason is that if the ratio is less than 1.1, there is no significant difference effect, and if it is greater than 10, the light guide becomes excessively large compared to the size of the light source and becomes impractical.
Further, by making the aperture width H1 of the lens on the entrance surface 10A smaller than the aperture width H2 of the lens on the exit surface 10B, as apparent from FIG. 4, the light incident on the lens on the entrance surface 10A in an oblique direction is obtained. When a portion is totally reflected at the upper smooth plane 16 or the smooth aspect 17, the tilt angle will have the effect of producing a reflected beam that is more parallel to the axis. The ratio of H2 / H1 that can effectively obtain this effect is preferably in the range of 1.1 to 10. The reason is that if the ratio is less than 1.1, an effect having a significant difference is not observed, and if the ratio is larger than 10, the light guide body 10 becomes excessive as compared with the size of the light source 11 and becomes impractical.

  Furthermore, the numerical aperture NA1 of the lens on the entrance surface 10A is made larger than the numerical aperture NA2 of the lens on the exit surface 10B, so that the acceptable range of incident light is widened, and the exit light is full of the aperture width H2 of the exit lens. Can produce effects that spread nearby. The ratio of NA1 / NA2 that can effectively obtain this effect is preferably in the range of 1.01 to 2. The reason is that if the ratio is less than 1.01, there is no significant difference effect. If the ratio is greater than 2, most of the exit lens is in a region where no light strikes.

  5-10, the light guide 10 is divided into two parts, a first light guide 10C having a lens 13 of an incident surface 10A, and a second light guide 10D having an exit surface 10B lens 13. As shown in FIG. A space (air layer portion) 33 in which the relative distance between the first light guide 10C and the second light guide 10D can be increased or decreased is provided between the first light guide 10C and the second light guide 10C in the space 33. It is preferable to include a place where the lens of the incident surface 10A and the lens of the output surface 10B can be arranged so as to substantially share the focal position within the relative distance adjustment range of the two light guides 10D. By providing the space 33 in the middle between the first light guide 10C and the second light guide 10D, even when using a light source that may generate a high temperature near the focus, such as a halogen lamp, the focus of the light guide is reduced. By placing the image position in the air, problems such as melting of the resin can be prevented.

  In addition, as shown in FIGS. 5 to 10, if the relative distance between the first light guide 10C and the second light guide 10D is increased or decreased, the emitted light beams are almost completely parallel as shown in FIG. As shown in FIG. 6, it can be used as a diffused light beam with a slight angle, as shown in FIG. 6, or as shown in FIG. You can also. In addition, due to problems such as lens processing accuracy, even when the integrated light guide 10 does not produce completely parallel light rays, it is possible to obtain parallel light rays in the process of adjustment as described above. There is also. The second surface 40 of the first light guide 10C and the first surface 41 of the second light guide 10D may be flat 16 as shown in FIGS. 5 to 7, respectively. It can also be a lens surface 17 as shown.

  FIG. 11 is a plan view schematically showing the structure of the illumination device 42 using the light guide 10 according to the third embodiment of the present invention, FIG. 12 is a sectional view taken in the direction of the arrows ZZ shown in FIG. 11, and FIG. It is an expansion perspective view which shows the light guide 10 used for FIG. 11, FIG. As shown in these drawings, the light guide body 10 is a linear long plate (rod) type, and two or more illumination light guide bodies 10 are arranged so that the light guide body 10 can rotate around the longitudinal axis. When the shafts 44 are connected to each other by appropriate rotating link means such as a bevel gear 43 so that irradiation can be performed at the same inclination angle, a quadrangular pyramid zoom luminaire can be realized.

  FIG. 13 is a perspective view showing a fourth embodiment of the light guide 10 according to the present invention, and FIG. 19 is a cross-sectional view taken in the YY direction of FIG. As shown in these figures, the light guide 10 may be formed into a truncated cone-shaped rod to produce a round irradiation beam. Also in this case, similarly to the second embodiment, the light guide 10 may be separated into the first light guide 10C and the second light guide 10D so that the relative position can be adjusted.

FIG. 15 is a perspective view showing a fifth embodiment of the light guide 10 according to the present invention. Thus, the light guide 10 can be a ring type.
Although FIG. 15 shows the light guide 10 in a state of being divided into two parts, the light guide 10 may be formed in one ring shape or divided into an arbitrary number according to the convenience of manufacturing and assembly. When combined, a ring shape may be formed.

  After making the light guide 10 into a ring shape as in the fifth embodiment, a bent portion 15 can be provided on at least a part of the light guide 10 as shown in the cross-sectional views of FIGS. . Alternatively, as shown in the cross-sectional view of FIG. 18, the total reflection surface 14 can be provided on at least a part of the light guide 10. According to these, it is possible to realize an illumination optical system that is a ring type and that irradiates a target place from a desired oblique direction.

It is sectional drawing which showed the joining implementation method of the light guide for illumination and LED by this invention. Example 1 It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. Example 1 It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. Example 1 It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. Example 1 It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. (Example 2) It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. (Example 2) It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. (Example 2) It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. (Example 2) It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. (Example 2) It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. (Example 2) It is the top view which showed the implementation method of the light guide for illumination by this invention. (Example 3) It is a ZZ direction arrow sectional view of the light guide for illumination shown in FIG. (Example 3) It is the perspective view which showed the implementation method of the light guide for illumination by this invention. (Example 4) It is the perspective view which showed the implementation method of the light guide for illumination by this invention. (Example 3) It is the perspective view which showed the implementation method of the light guide for illumination by this invention. (Example 5) It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. (Example 6) It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. (Example 6) It is sectional drawing which showed the implementation method of the light guide for illumination by this invention. (Example 6) It is a YY direction arrow sectional view of the light guide for illumination by this invention shown in FIG. (Example 4)

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light guide 10A Incident surface 10B Output surface 10C 1st light guide 10D 2nd light guide 11 LED light source F Focus 12 Spherical lens 13 Cylindrical lens 14 Total reflection surface 15 Bending part 16 Plane 17 Curved surface 30 Parallel rays 31 Convergent rays 31 32 Diffused light 33 Space (air layer part)
40 Second surface (light exit surface) of first light guide 10C
41 1st surface (light incident surface) of 2nd light guide 10D
42 Illuminating Device 43 Bevel Gear 44 Shaft 45 Case M Motors

Claims (10)

A light guide for illumination, comprising a lens on each of an entrance surface and an exit surface of a light guide, wherein the entrance surface lens and the exit surface lens substantially share a focal position. A space in which the relative distance between the first light guide and the second light guide can be increased or decreased is provided between the first light guide having the entrance surface lens and the second light guide having the exit surface lens. The light guide for illumination includes a place where the entrance surface lens and the exit surface lens can be arranged so as to substantially share the focal position within the relative distance adjustment range. 3. The illumination light guide according to claim 1, wherein the curvature radius R1 of the entrance surface lens is smaller than the curvature radius R2 of the exit surface lens. . 4. The illumination light guide according to claim 1, wherein an opening width H1 of the entrance surface lens is formed to be smaller than an opening width H2 of the exit surface lens, and The opening end of the exit surface lens is connected to each other by a smooth plane or curved surface, that is, the side surface portion of the light guide for illumination is formed into a flat or curved surface having a smooth surface. Light guide. 5. The illumination light guide according to claim 1, wherein the numerical aperture NA1 of the entrance surface lens is larger than the numerical aperture NA2 of the exit surface lens. 6. The illumination light guide according to claim 1, wherein the light guide has a linear rod shape, a truncated cone shape, or a cross section perpendicular to the axial direction (longitudinal direction) of the light guide. A light guide for illumination, which is a rod shape that is substantially a keyhole shape. The light guide for illumination according to claim 6, wherein the light guide is configured to be rotatable about a longitudinal axis, and two or more light guides for illumination having such a structure are connected to an appropriate rotation link. A light guide for illumination, which is connected by means so as to be able to irradiate at the same inclination angle. 6. The illumination light guide according to claim 1, wherein the illumination light guide has a ring shape in which a side portion of the light guide is formed by a curved surface. 9. The illumination light guide according to claim 1, wherein at least part of the light guide includes a bent portion. 9. The illumination light guide according to claim 1, wherein at least a part of the light guide includes a reflective surface.

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