JP2009001277A - Bicycle light using bulk lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bicycle light using a bulk lens capable of generating power without giving any friction to a wheel, supplying the power to a light source such as an LED and a semiconductor laser, and converging the light therefrom and emitting it outside. <P>SOLUTION: This bicycle light comprises the bulk lens 20, the light source 1 accommodated in this bulk lens 20, and a power generating unit 30 for supplying a current to the light source 1 based on an electromotive force generated by a change in a magnetic flux of a magnet. The bulk lens 20 is formed of an optical medium having a top part, a bottom part, an outer circumferential part, and a recessed part comprising a ceiling part and an inner circumferential part formed from the bottom part to the top part. The recessed part forms an accommodation part for the light source, and the ceiling part, the outer circumferential part, the bottom part and the top part function as a first lens surface, a light incident surface, a total reflection surface, a reflecting surface, and a second lens surface, respectively. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bicycle light using a lens suitable as an optical lens for a semiconductor light emitting element such as a light emitting diode (LED), based on the proposal of an optical lens having a novel structure. Further, the present invention relates to a bicycle light that uses a light source that condenses light emitted from a semiconductor element with a lens having a novel structure and emits it to the outside as a light source.

  Semiconductor light emitting devices such as light emitting diodes (LEDs) directly convert electrical energy into light energy, and therefore have a feature that is more efficient than incandescent bulbs such as halogen lamps and fluorescent lamps, and does not generate heat during light emission. . Incandescent bulbs convert electrical energy into thermal energy and use light radiation accompanying the heat generation, and the conversion efficiency of electrical energy into light is low and does not exceed 1%. In a fluorescent lamp, electric energy is converted into discharge energy, and the conversion efficiency into light is still low. On the other hand, in the LED, the conversion efficiency of electric energy into light can be over 20%, and a conversion efficiency exceeding 100 times that of an incandescent bulb or a fluorescent lamp can be easily achieved. Furthermore, a semiconductor light-emitting element such as an LED has a long lifetime that can be said to be semi-permanent, and does not have the problem of flickering like a fluorescent lamp. Therefore, it can be said that it is a human-friendly light source that does not adversely affect the eyes and the human body.

Although the LED has such an excellent feature, the light emission area is a small area of about 1 mm ^2, so when used as illumination light or a light source, a single LED has insufficient luminous flux, and many It is necessary to arrange the LEDs. Further, since the LED has a divergence angle as large as 90 degrees in a chip state and around 40 degrees even in a package type, a lens for converging light is required. For this reason, a large number of LEDs must be arranged in a matrix, and a light focusing lens must be attached to each LED. However, if a conventional optical system using a convex spherical lens or the like is used, the divergence angle of the LED is large. Therefore, if it is attempted to converge with a low light loss, the lens system becomes enormous and the LEDs cannot be arranged closely. Or, if the lens system is made small and the LEDs are closely arranged, there arises a problem that the light loss becomes extremely large. In addition, when a conventional lens system is used, a holder that holds the LED and the lens with the optical axis aligned is necessary, and such a holder requires high precision processing, and thus costs are increased. Further, when the LED and the lens are fixed to the holder, an optical axis alignment adjustment process is required, which increases the cost.
The above-mentioned problems are the main causes that LEDs are not used as illumination light or light source.

  By the way, as a conventional bicycle light, it is generally known that a rotating portion (especially a roller) of a generator is brought into contact with a tire and the power of the light is generated by the rotation of the roller. A light bulb is used as a source (see Patent Document 1). The roller as the rotating part is subjected to a rough surface treatment in which a plurality of grooves and the like are provided so that the surface has a large friction coefficient.

JP 07-108967 A

In such a bicycle light, since a light bulb is used, the power consumption increases and the amount of power generation must also be large, so the generator itself becomes large.
In addition, since a generator with a large amount of power generation is used for power generation, it is necessary to increase the force of depressing the pedal to rotate the wheels.
Further, when a light source such as an LED is used instead of a light bulb, the illuminance of light emitted from the LED is not sufficient for lighting a light as described above.

  Therefore, the present invention was created to solve the above-described problems, and generates power without giving friction to the wheels, supplies the power to a light source such as an LED or a semiconductor laser, and condenses the light. An object of the present invention is to provide a bicycle light using a bulk lens that can be emitted to the outside.

In order to achieve the above object, a bicycle light using a bulk type lens according to the present invention includes a bulk type lens, a light source housed in the bulk type lens, and an electromotive force generated by a change in magnetic flux of the magnet. The bulk-type lens includes a top, a bottom, an outer periphery, and a recess formed by a ceiling and an inner periphery formed from the bottom toward the top. The concave portion is the light source storage portion, the ceiling portion is the first lens surface, the inner peripheral portion is the light incident surface, and the outer peripheral portion is the total reflection surface. The bottom part functions as a reflecting surface, and the top part functions as a second lens surface.
When the light source is housed inside the recess, the ceiling functions as the lens entrance surface and the top functions as the lens exit surface. The light incident on the optical medium from the inner periphery is totally reflected or reflected at the bottom and transmitted to the top. “Bulk type” means a solid body having a certain degree of thickness or swelling, such as a shell type, egg type, saddle type, saddle type. The cross-sectional shape perpendicular to the optical axis direction can be a perfect circle, an ellipse, a triangle, a quadrangle, a polygon, or the like. The outer peripheral portion of the bulk type lens body may be a surface parallel to the optical axis, such as a circular column or a peripheral portion of a prism, and may have a taper with respect to the optical axis. In addition, the lens surface at the ceiling and the top can be appropriately selected from a convex surface, a concave surface, a flat surface, and a Fresnel lens surface.

  The bulk type lens used in this bicycle light has a lens function and an optical transmission function to connect the entrance surface and the exit surface, so it is a material transparent to the wavelength of light and has a refractive index of refraction of air. The rate needs to be different. As such a material, various glass materials such as transparent resin (transparent plastic material) such as acrylic resin, quartz glass, soda-lime glass, borosilicate glass, lead glass, and the like can be used. Alternatively, a crystalline material such as zinc oxide (ZnO), zinc sulfide (ZnS), or silicon carbide (SiC) may be used. Also, a material such as a transparent rubber having flexibility, flexibility and stretchability may be used. When an incandescent bulb such as a halogen lamp is used as the light source, a heat resistant optical material should be used in consideration of the heat generated by this. As the heat resistant optical material, heat resistant glass such as quartz glass and sapphire glass is preferable. Alternatively, a heat-resistant optical material such as a heat-resistant resin such as a polysulfone resin, a polyether sulfone resin, a polycarbonate resin, a polyetheresteramide resin, a methacrylic resin, an amorphous polyolefin resin, or a polymer material having a perfluoroalkyl group It can be used. Crystalline materials such as SiC are also excellent in heat resistance.

  The light source is preferably a light source that does not cause a significant heat generation effect during light emission, such as an LED or a semiconductor laser. If an LED or the like is used, when the “light source” is housed in the concave portion (housing portion) of the bulk type lens according to the first feature of the present invention, the thermal effect is exerted on the bulk type lens by the heat generation action. Never give.

  By using the bulk type lens, it is possible to easily obtain a bicycle light having a desired illuminance without requiring a large number of light sources for the bicycle light. This illuminance cannot be achieved by a conventionally known optical system such as a lens if the number of light sources is the same. The present invention can realize illuminance that cannot be achieved by conventional techniques with a simple and compact configuration. Although details will be described later, conventional thin lenses such as “biconvex lens”, “planoconvex lens”, “meniscus convex lens”, “biconcave lens”, “planoconcave lens”, “meniscus concave lens”, etc., have large infinite diameters. Unless a lens is used, a function equivalent to the bulk lens used in the bicycle light of the present invention cannot be achieved.

An LED has an internal quantum efficiency and an external quantum efficiency. Usually, the external quantum efficiency is lower than the internal quantum efficiency. By storing the LED in the storage portion (concave portion) with the bulk lens used in the present invention, it becomes possible to effectively extract the light energy of the potential LED with an efficiency substantially equal to the internal quantum efficiency.
The principle is that (a) the reflected light (stray light) at the top surface and the ceiling portion of the bulk type lens and the outer peripheral portion is totally reflected at the outer peripheral portion, so that it hardly dissipates outside the bulk type lens. ) A part of the reflected light (stray light) returns to the lens surface that is the top part and the ceiling part. (C) A part of the reflected light (stray light) is reflected at the bottom part and returns to the lens surface that is the top part and the ceiling part. (D) A part of the reflected light (stray light) is absorbed by the LED light source and re-emitted, and (e) light incident on the inner surface is also guided by total reflection and used effectively. Conceivable.

  Further, according to the bulk type lens used in the present invention, the light source itself such as LED can easily change the optical path such as light divergence and convergence and change the focal point without any modification. That is, if the divergence angle of the light source according to the first feature of the present invention is known, it is possible to easily select the curvature radii of the first and second curved surfaces. Note that either one of the first and second curved surfaces may be a flat surface with an infinite curvature radius or near infinity. If either one of the first and second curved surfaces has a predetermined (finite) radius of curvature that is not infinite, the convergence and divergence of light can be controlled. The “predetermined divergence angle” may be 0 °, that is, a parallel light beam. Even if the divergence angle is 90 degrees, the storage portion completely covers the light emitting portion of the light source, so that the light can be effectively collected. This is an operation that is impossible with a conventional optical system such as a lens. That is, the inner peripheral part of the storage part other than the ceiling part can also function as an effective light incident part.

Specifically, the light source according to the first object of the present invention is a chip-shaped semiconductor light emitting element, a semiconductor light emitting element molded with a transparent material, or an emission end face of an optical fiber that guides light from another light source. . These light sources may be stored in the storage unit via an optical medium. By appropriately selecting the optical medium according to the refractive index, it is possible to change the optical path such as light divergence and convergence, and change the focal point, and also to change the refraction angle of light incident on the recess from the inner peripheral surface. It is also possible to make the total reflection of the recess more effective.
Here, the optical medium includes not only solids, liquids, and gases, but also substances that are transparent to the wavelength of light in the form of sol, colloid, or gel.

In order to achieve the above object, the bicycle light using the bulk type lens of the present invention has a bulk type lens, a light source housed in the bulk type lens, and an electromotive force generated by a change in magnetic flux of the magnet. A power generation unit that supplies current to the light source, and the bulk lens includes a top, a bottom, an outer peripheral, and a ceiling and an inner peripheral formed from the bottom toward the top. An optical medium having a concave portion, the concave portion is a light source storage portion, the ceiling portion is a first lens surface, the inner peripheral portion is a light incident surface, and the outer peripheral portion is a total reflection surface The bottom portion functions as a reflecting surface, the top portion functions as a second lens surface, and the light incident surface of the inner peripheral portion is configured by an uneven surface having a predetermined inclination and a size of at least the light wavelength or more. Features that are It is.
According to this configuration, for example, even when using an LED that emits most of the emitted light from the side surface of the chip, such as an edge-emitting LED, all the emitted light can be condensed. The predetermined inclination φ is sin ⁻¹ {n, where n _{1 is} the refractive index of the recess, n _{2 is} the refractive index of the optical medium, and the total reflection angle at the outer peripheral surface in the optical medium is the divergence angle of the θt light source. ₁ / n ₂ cos (θd + φ)} = θt.

Furthermore, the power generation unit is preferably configured to include a magnet attached to at least one spoke of the wheel, and a coil attached to the vehicle body with the axis perpendicular to the rotation surface of the wheel. The current supplied to the light emitting element is based on an electromotive force generated by a change in magnetic flux of the magnet that crosses the vicinity of the opening of the coil due to rotation of the wheel.
The bicycle light preferably includes a control unit that controls supply of current generated by the power generation unit to the light source, and a detection unit that detects light and sends a light detection signal to the control unit. The controller is configured to automatically switch the light source on and off based on a signal from the detector.

The bicycle light is preferably provided with a diode that converts an alternating current generated by the power generation unit into a direct current.
Further, the bicycle light may be provided with a capacitor for supplying an alternating voltage generated by the power generation unit to the light source. Furthermore, the bicycle light of the present invention is preferably configured by providing a magnetic body in the coil. Furthermore, the magnet may be formed in a horseshoe shape.

  The bicycle light of the present invention can significantly increase the illumination intensity of the light by using a bulk lens without increasing the number of semiconductor elements, and effectively use the light emission of semiconductor elements such as LD and LED. Even a relatively expensive light-emitting element can be used sufficiently for practical use.

Thus, according to the bicycle light of the present invention, since a light emitting source such as an LED is used, it is possible to reduce power consumption as compared with a light bulb, and as a result, it is possible to reduce the generator. In addition, since the light emitted from the light source is collected by the bulk lens and emitted to the outside, light with high illuminance can be obtained.
Furthermore, since the bicycle light is configured to supply an electromotive force based on a change in magnetic flux to the light source, there is no friction between the roller of the conventional generator and the tire, so the conventional roller contacts the tire. You can lighten the pedal of the bicycle compared to when you are.
In addition, since the power consumption of the light source such as LED is 1/10 to 1/100 that of a light bulb, a generator having a simple structure including a coil, a magnetic body, and a magnet may be used, for example. Can be configured.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Accordingly, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

FIG. 1 is a block diagram showing a bicycle light using a bulk lens according to an embodiment of the present invention. The bicycle light 100 shown in FIG. 1 generates electricity without giving friction to wheels, and the electric power is emitted from an LED. Or a light source such as a semiconductor laser, and the light is collected and emitted to the outside.
For this reason, as shown in FIG. 1, the bicycle light 100 includes a light source 1, a bulk lens 20, and a power generation unit 30.
The light source 1 is a semiconductor element such as an LED that has little heat generation action when emitting light, and the power generation unit 30 supplies a voltage (current) to the light source 1 based on an electromotive force generated by a change in magnetic flux.
The bulk type lens 20 can use a commercially available light source such as an LED and has high condensing efficiency. If the bulk type lens 20 is used, a desired number of light sources can be obtained without requiring a large number. Can be obtained.
Here, the bulk type lens 20 used for the bicycle light 100 will be described by dividing it into a first embodiment, a second embodiment, and modifications thereof.

A first example of the bulk type lens will be described.
FIG. 2 is a schematic cross-sectional view of the light source 1 of the illumination light and the bulk lens 20 used in the embodiment of the present invention. As shown in FIG. 2, the illumination light includes at least a light source 1 such as an LED that emits light of a predetermined wavelength band, and a bulk lens 20 that completely surrounds the light source 1. The bulk lens 20 is an optical medium including a top portion 3, a bottom portion 7, an outer peripheral portion 9, and a concave portion 6 including a ceiling portion 2 and an inner peripheral portion 5 formed from the bottom portion 7 toward the top portion 3. The light source 1 is accommodated and fixed concentrically and completely with the bulk type lens 20 through the spacer 8 in the recess 6, the ceiling portion 2 serves as the light incident surface of the lens, and the top portion 3 serves as the exit surface of the lens. Is configured to function as

  The light source 1 in FIG. 2 includes an LED chip 13, a support pin 11 that also serves as an electrode on which the LED chip 13 is placed, an electrode pin 12 that supplies power to the other electrode of the LED chip 13, a chip 13, It is composed of a transparent resin mold 14 that covers the support pins 11 and the electrode pins 12. The resin mold 14 has a cylindrical side portion, and is fitted to the inner peripheral portion 5 of the concave portion 6 of the bulk lens 20 via the spacer 8.

  The side surface of the resin mold 14 has, for example, a cylindrical shape with a diameter (2r) of 2 to 3 mmφ, and the inner peripheral portion 5 of the concave portion 6 of the bulk lens 20 has a cylindrical shape with a diameter of 2.5 to 4 mmφ, for example. ing. In order to fix the LED 1 and the bulk lens 20, a spacer 8 having a thickness of about 0.25 to 0.5 mm is inserted between the LED 1 and the concave portion 6 of the bulk lens 20. The spacer 8 is disposed at a position excluding the light emitting portion of the LED 1, that is, on the bottom 7 side from the bottom surface of the LED chip 13 in FIG. 2.

In the bulk type lens 20, for example, the top portion 3 has a convex spherical surface, and the outer peripheral portion 9 has a cylindrical shape. The diameter (2R ₀ ) of the outer peripheral portion 9 is, for example, 10 to 30 mmφ, and can be arbitrarily selected according to the purpose of use. However, in order to increase the light collection efficiency,
10r> R ₀ > 3r (1)
It is preferable to satisfy this relationship. Even if the diameter (2R ₀ ) of the outer peripheral portion 9 of the bulk lens 20 is 10 times the inner diameter (2r) of the inner peripheral portion 5 of the recess 6, the bulk lens according to the embodiment of the present invention functions, but is necessary. It is not preferable for the purpose of increasing the size and reducing the size.

The bulk lens used in the present invention having the above-described configuration can be converged with an extremely low loss compared to an optical system using a conventional convex spherical lens for the following reason. Since an LED is a light source with a large divergence angle, light loss is inevitable if all light emitted from the LED is converted into parallel rays by a conventional convex spherical lens.
FIG. 3 is a diagram showing the light collecting action of a conventional convex spherical lens, and FIG. 3 (A) shows a state in which light from an LED light source is converted into parallel light using a convex half spherical lens. Yes. In the figure, the lens has a radius of curvature r and is located at a focal length f from the light source. The focal length of the one-spherical lens is f = r / (n−1), where n is the refractive index of the lens, and therefore f = 2r when the refractive index n = 1.5. Therefore, as is apparent from the figure, the maximum divergence angle that the lens can receive is 30 °, and the light beam shown in B in the figure cannot be parallel light. That is, when a conventional lens is used, light having an opening angle or more determined from the relationship between the focal length and the radius of curvature cannot be taken in, so that the loss is large.
Many LED light sources have a divergence angle of 30 ° or more, and in this case, a large loss occurs for the above reason. Conventionally, in such a case, improvement is made by using a high refractive index lens, but the cost becomes high. Alternatively, there is an example of dealing with a complicated combination of lenses, but in this case, the Fresnel reflection loss described below increases.

FIG. 3B is a diagram showing the state of reflection on the incident surface of a conventional convex half-spherical lens. In the figure, a line with an arrow represents a light ray emitted from the LED 1 and reflected by the light incident surface of the convex spherical lens. θ (θ ₁ , θ ₂ ) represents an emission angle from the LED, that is, a divergence angle, and φ (φ ₁ , φ ₂ ) represents an incident angle of each light beam on the lens surface.
FIG. 4 is a diagram showing Fresnel's law of reflection. In the figure, the horizontal axis represents the incident angle of the light beam, the vertical axis represents the reflectance of the light intensity, the refractive index of the lens is 1.5, and the light beam is incident on the lens surface from the air. As is apparent from the figure, the reflectance is low and constant until the incident angle is around 50 °, but the reflectance increases abruptly when the angle exceeds 50 °.
The light ray having a large incident angle shown in FIG. 3B has a high ratio of being reflected as apparent from the Fresnel reflection law of FIG. For example, when a single-convex spherical lens having a refractive index of 1.5 is used and parallel light is produced by using a light source with a divergence angle of 30 ° at the focal length of the lens, the loss due to the reflected light is the total amount of light. Reaches nearly 30%.
Therefore, if the lenses are connected in multiple stages as in the conventional optical system, Fresnel reflection occurs in multiple stages, increasing the loss. These reflected lights are scattered in space and cannot be used as convergent light.

On the other hand, in the bulk type lens according to the embodiment of the present invention, even a light beam having a large divergence angle, all the light beams can be incident on the lens surface. This is a lens with very little loss.
Further, since the reflecting surfaces that cause Fresnel reflection are the ceiling portion 2 and the top portion 3, the reflected light (stray light) reflected by these surfaces is reflected in the bulk lens. These reflected lights (stray light) are not scattered outside the bulk lens by being totally reflected by the outer peripheral part 9, but return to the lens surface, which is partly the top part 3 and the ceiling part 2, and become convergent light. The other part is reflected by the bottom 7 and returns to the top 3 or the ceiling 2 to become convergent light. The other part is absorbed by the LED light source and re-emitted to become convergent light.

FIG. 5 is a diagram illustrating a process in which the light returned to the LED light source 1 is re-emitted.
In the figure, the returned light is absorbed by the PN junction to generate holes and electrons, and these holes and electrons recombine to re-emit light. This effect is particularly significant in the case of an LED having a heterostructure. In the heterostructure LED, the band gap energy of the PN junction that is the light emitting part is formed smaller than the band gap energy of the P and N regions, so that reflected light (stray light) is absorbed in the P or N region. Instead, it is absorbed only at the PN junction and re-emits light.
Furthermore, in the bulk type lens according to the embodiment of the present invention, light incident on the inner peripheral portion 5 is also guided to the top portion 3 by total reflection at the outer peripheral surface 9 and is emitted as convergent light. This effect is further enhanced when the LED light source 1 is housed in the housing portion via an optical medium having a refractive index higher than that of the optical medium of the bulk lens.
In the bulk type lens according to the embodiment of the present invention, the light of the LED light source is effectively extracted as the convergent light with the efficiency substantially equal to the internal quantum efficiency due to the synergistic effect described above. It is considered that the loss is extremely low compared to a spherical lens.

  FIG. 6 is a diagram showing a measurement system for comparing characteristics when parallel light is created by the first example of the bulk type lens according to the embodiment of the present invention and a conventional convex spherical lens. . FIG. 6A is a schematic diagram showing a measurement system for measuring the light intensity (illuminance) distribution in the direction perpendicular to the optical axis direction when the bulk lens 20 is used. The intensity (illuminance) of the output light from the exit surface of the bulk lens 20 is measured by moving the illuminometer 102 in the y-axis direction with the measurement distance x from the LED 1 being constant. The measurement distance (x) is measured in the optical axis direction. On the other hand, FIG. 6B is a diagram showing that the same measurement is performed using a conventional biconvex lens.

  In the measurement shown in FIGS. 6A and 6B, the outer diameter of the bulk lens 20 used in the present invention is 30 mmφ, and the outer diameter of the biconvex lens 101 used for comparison is 63 mmφ, which is slightly more than twice this. . A biconvex lens 101 having a focal length of 150 mm was used, and was arranged at a position of 150 mm from the LED 1 in the x direction. The LED light source 1 used a divergence angle of about 12 degrees.

FIG. 7 is a diagram comparing characteristics in the case where parallel light is generated by the first example of the bulk type lens according to the embodiment of the present invention and a conventional convex spherical lens. The intensity (illuminance) distribution along the y direction of the output light of each of the bulk type lens 20 according to the present invention, the conventional thin lens (biconvex lens) 101, and the bare LED that does not use the bulk type lens is measured distance x = 1 m. The result when measured in is shown. The bulk lens 20 according to the first embodiment of the present invention has twice the illuminance as the conventional thin lens (biconvex lens) 101.
This result shows that the bulk type lens according to the embodiment of the present invention has an effect that cannot be realized by the conventional optical system.

FIG. 8 is a diagram in which the parallelism of the parallel light created by the first example of the bulk lens according to the embodiment of the present invention and the conventional convex spherical lens is evaluated.
FIG. 7 summarizes data obtained by measuring the intensity (illuminance) distribution along the y direction while changing the measurement distance x in the same manner as in FIG. 6. The horizontal axis of the figure indicates the square of the reciprocal of the measurement distance x, that is, 1 / x ² , and the vertical axis indicates the maximum intensity (peak intensity) at the measurement distance x. As apparent from the figure, in the case of the bulk type lens according to the embodiment of the present invention, the measurement points are clearly plotted on the line indicating the inverse square law, that is, 1 / x ² . On the other hand, it can be seen that the conventional thin lens (biconvex lens) 101 deviates from the inverse square law.
This result shows that the bulk lens 20 is sufficient in parallelism, and can achieve performance that is not inferior to that of the conventional lens system.

FIG. 9 is a diagram showing the relationship between the geometric structure of the bulk lens used in the present invention (first embodiment) and the light collection rate. Here, the “condensation rate” is “amount of output light at a divergence angle within ± 1 ° from a bulk lens” as “amount of light at a divergence angle within ± 12 ° from a light source (LED)”. It is defined by the divided amount. That is, the amount corresponds to the beam diameter. The radius of curvature R of the top 3, the total length L of the bulk type lens, the medium length (distance between the lenses of the top and the ceiling) D, the inner diameter of the storage part (inner peripheral part system) r, the length of the curvature part Δ of the ceiling 2 As a parameter, the light collection rate was measured. Here, as shown in FIG. 2, the sign of Δ is defined as negative when the ceiling 2 is concave and defined as positive when convex.
FIG. 10 is a diagram showing a geometric structure of a bulk lens according to an embodiment of the present invention. From FIG. 9, in order to improve the light collection rate,
0.93 <k (R / L) <1.06 (2)
k = 1 / (0.35 · n -0.168) (3)
It is experimentally found that it is preferable to satisfy Here, n is the refractive index of the optical medium that is the material of the bulk lens. The radius Ro of the cylindrical portion of the bulk lens 20 and the curvature radius R of the top 3 are not necessarily equal.

Next, a second structure example of the bulk type lens of the present invention will be described.
FIG. 11 is a diagram showing the structure of the bulk lens of the present invention in which the ceiling 2 is convex. 11, the bulk lens 22 is the same as the bulk lens 20 shown in FIG. 2 except that the shape of the ceiling portion 2 is different. The outer diameter 2Ro of the cylindrical portion of the bulk type lens 22 used for the measurement is 15 mmφ, the total length L of the bulk type lens is 25 mm, the distance D between the top and ceiling lenses is 16 mm, and the inner diameter r of the storage portion 6 is 5. The refractive index n of the 2 mm bulk lens is 1.54. The radius of curvature R of the top 3 of this bulk lens is 8.25 mm. The resin-molded LED 1 used for the measurement has an outer diameter of 5 mmφ.

  FIGS. 12A to 12C and FIGS. 13A to 13C are diagrams illustrating the relationship between the height Δ of the convex portion of the ceiling portion 2 and the beam intensity profile. The illuminance was measured at a distance x = 1 m from the light source. As can be seen from the figure, the light condensing characteristic can be obtained even when the ceiling 2 is a convex lens.

  In this way, according to the light emitters according to the first and second embodiments used in the present invention, a desired irradiation as a light beam contributing to illumination can be achieved without requiring a large number of resin-molded LEDs 1. A light flux with an area can be secured and desired illuminance can be easily obtained. This illuminance is an illuminance that cannot be achieved by a conventionally known optical system such as a lens. Surprisingly, it could be realized with only one LED having the same illuminance as a thin flashlight using a halogen lamp currently on the market. Thus, according to the light emitter of the first embodiment used in the present invention, illuminance that cannot be realized by the conventional technique can be realized with a simple structure as shown in FIG.

  As the resin-molded LED 1 used for the light emitters according to the first and second embodiments used in the present invention, LEDs of various colors (wavelengths) can be used. However, white LEDs are natural to the human eye for lighting purposes as bicycle lights. White LEDs having various structures can be used. For example, three LED chips of red (R), green (G), and blue (B) may be stacked vertically. In this case, a total of six pins may be derived from the resin mold 14 corresponding to the LED chips of the respective colors, and the six pins are combined into two as the internal wiring of the resin mold 14 and used as external pins. May be a structure in which two are provided. If one electrode (ground electrode) is used in common, the number of external pins may be four. Also, if the drive voltages of the three LED chips of red (R), green (G) and blue (B) can be controlled independently of each other, any color can be mixed. It is possible to enjoy the change in hue.

  As the bulk type lens 20 of the luminous body according to the first and second embodiments used in the present invention, various types of glass such as transparent plastic materials such as acrylic resin, quartz glass, soda lime glass, borosilicate glass, lead glass and the like. Materials etc. can be used. Alternatively, a crystalline material such as ZnO, ZnS, or SiC may be used. Further, a material such as sol, gel, sol-gel mixture, or transparent rubber having flexibility, flexibility or stretchability may be used. Also, sol, gel, sol-gel mixture, etc. may be stored in a transparent rubber or flexible transparent plastic material. A transparent plastic material such as an acrylic resin is a suitable material for mass-producing the bulk lens 20. That is, once a mold is formed and molded by this mold, the bulk lens 20 can be easily mass-produced.

Next, modifications of the first and second embodiments will be described.
The bulk type lens used in the modified examples of the first and second embodiments can be used even with a light source that emits light from the side surface of the LED chip, such as an edge-emitting LED. Since the edge-emitting LED emits light from the side surface of the LED chip, when this LED chip is mounted on the bulk type lens of the first and second embodiments, a component that is perpendicularly incident on the inner peripheral portion 5 of the bulk type lens is present. Therefore, the amount of light scattered outside the bulk lens without being totally reflected increases.
The bulk type lenses of the modified examples of the first and second embodiments can obtain convergent light even with such a light source with extremely low loss.

FIG. 14 is a diagram showing an optical path of a light beam when the inner peripheral portion 5 and the outer peripheral portion 9 of the bulk type lens of the present invention have an inclination.
In the figure, the divergence angle of the light source is θd, the inclination angle between the inner peripheral portion 5 and the outer peripheral portion 9 is φ, the total reflection angle of the outer peripheral portion 9 is θt, and the incident angle and the refraction angle of the light beam at the inner peripheral portion 5 are θ _1. And θ ₂ , the refractive index of the optical medium of the bulk lens, and the refractive index of the storage portion (concave portion) 6 are n ₂ and n ₁ . The figure shows a state in which a light beam having a maximum light emission angle, that is, a divergence angle satisfies a total reflection condition with a tilt angle φ and is totally reflected.
In the inner periphery 5, according to Snell's law of refraction, between θ ₁ and θ ₂ ,
sin θ ₁ / sin θ ₂ = n ₂ / n ₁ (4)
Holds, but also, as is apparent from FIG, [theta] t, phi, between theta ₂ is
θt = φ + θ ₂ (5)
Holds. As is clear from FIG, [theta] d, theta _1, during the φ is
θd = 90 ° − (θ ₁ + φ) (6)
The relationship holds. If θ ₁ and θ ₂ are eliminated from the above expressions (4), (5), and (6), the bulk lens has total reflection angle θt and the light source has a divergence angle of θd to totally reflect. As a relational expression that gives the necessary tilt angle φ,
sin ⁻¹ {n ₁ / n ₂ cos (θd + φ)} = θt (7)
Is obtained. That is, if the inner peripheral portion 5 and the outer peripheral portion 9 are inclined at an inclination angle φ satisfying the expression (7) or more, even if light is incident on the inner peripheral portion 5 vertically (θd = 90 °), total reflection is performed. Since the light is reflected to the top 3 or reflected from the bottom surface 7 and guided to the top 3, convergent light can be obtained.

FIG. 15 is a diagram showing the configuration of the bulk lens.
FIG. 15A shows an example in which fine irregularities are provided on the surface of the inner peripheral portion 5 of the bulk lens 20. The unevenness has an inclination angle of φ or more that satisfies at least the expression (7), and the size of the unevenness may be about the light wavelength. Further, the unevenness only needs to be provided in the vicinity of the light source of the inner peripheral portion 5.
Such irregularities can be easily formed by polishing the surface of the inner peripheral portion 5 using an abrasive having an appropriate particle size.
FIG. 15B shows a state in which a light beam emitted substantially in the lateral direction is totally reflected inside the bulk lens or reflected by the bottom surface 7 and totally reflected by the side wall and guided to the top portion 3. Thus, for example, even when using an LED that emits most of the emitted light from the side surface of the chip, such as an edge-emitting LED, all the emitted light can be converged.
Furthermore, since the lens unit and the storage unit for storing the light source are integrally formed, there is no need for a holding unit for optically aligning and holding the lens and the light source, which is necessary in the conventional lens system. In addition, since the optical alignment process is not required and only the light source is covered, the cost is extremely low.

  Next, an example of the bicycle light of the present invention will be described by illustrating the configuration of the power generation unit 30. 16 is a perspective view showing a bicycle light 111 according to an embodiment of the present invention, FIG. 17 is a sectional view of FIG. 16, and FIG. 18 is a perspective view showing a state in which the bicycle light is attached to the bicycle. .

  As shown in FIG. 17, the bicycle light 111 includes a plurality of bulk lenses 20, a light source 1 housed in a housing portion (concave portion) 6, and a circuit 41 inside a resin-molded case 40. The circuit board 42 mounted, a cylindrical coil 43, a magnetic body 44 inserted into the cylinder, and a magnet 50 disposed outside the case 40 are configured.

The case 40 has a light exit opening at its end, and a drip-proof cover 45 for drip-proof the light source is fitted into the light exit opening. The drip-proof cover 45 is made of an acrylic plate or a plastic plate with good light transmission.
As shown in FIG. 17, each bulk lens 20 is attached by inserting the bottom portion 7 into a hole 46 a formed in a lens fixing plate 46 fitted in the case 40. 20 and the lens fixing plate 46 are fixed by adhesion or melting.

The circuit 41 is designed to supply the same voltage (current) to each of the plurality of light sources 1, and the circuit 41 and the coil 43 are short-circuited by wiring members 47 and 47. Each light source 1 connected to the circuit 41 is inserted into the hole 46 a of the lens fixing plate 46 and accommodated in the accommodating portion (concave portion) 6 of the bulk type lens 20.
In addition, although the coil 43 is formed in the cylindrical shape of N (> 0) winding, you may form in a rectangular parallelepiped shape.

  As shown in FIG. 17, the end of the case 40 that faces the light exit port can be separated in order to sandwich the bicycle shaft 60. That is, the holding part 40a which can be attached or detached with the volt | bolt 48a and the nut 48b is attached to the edge part of the case 40. As shown in FIG. Grooves 401 and 402 for sandwiching the bicycle shaft 60 are respectively provided in the surface where the holding portion 40a and the case 40 come into contact with each other. The bicycle shaft 60 is sandwiched between the case 40 and the sandwiching portion 40a, that is, the fixing hole formed by the groove 401 and the groove 402, and the case 40 and the sandwiching portion 40a are fixed by the bolt 48a and the nut 48b. The case 40 is attached to the bicycle. In addition, each case 40 and the clamping part 40a are formed with a dent 49 so that the bolt 48a and the nut 48b do not protrude to the outside.

Next, the coil 43 and the magnetic body 44 are provided in the case 40 so that their cylindrical axes are perpendicular to the rotation surface of the wheel, and the case 40 is fixed to the coil 43 and the magnetic body 44 therein. The resin is molded as described.
On the other hand, the magnet 50 provided outside the case 40 is a permanent magnet, such as (1) strontium / ferrite magnet, (2) samarium / cobalt magnet, (3) neodymium / iron / boron magnet, (4) samarium / iron / Nitrogen magnets, (5) alnico magnets, and the like can be used.

  As shown in FIG. 19, the magnet 50 is formed in a disk shape, and the two magnets 50 are attached to one side of a high-permeability plate 51 such as pure iron, silicon steel, or directional silicon steel as a whole. It is formed to have a horseshoe shape. The two magnets 50 attached to the plate 51 are attached such that the surface exposed to the outside is a counter electrode. Further, as shown in FIGS. 17 and 20, the magnets 50 and 50 and the plate 51 are accommodated in a protective cover 52 to prevent adhesion of iron sand, water, etc., and together with the protective cover 52, the spokes 61 of the wheel are accommodated. It is attached. The protective cover 52 is separable into two parts, which sandwich the spokes 61 and integrate them with screws 53 or the like, so that the magnet 50 is attached to the spokes 61. The protective cover 52 is made of resin, Teflon (registered trademark), plastic, or the like. Further, as shown in FIG. 17, the plate 51 on which the magnet 50 shown in FIG. 19 is mounted is attached to the spoke 61 with the mounting surface of the magnets 50 and 50 facing the coil 43 or the magnetic body 44 side.

On the other hand, the case 40 containing the bulk lens 20, the light source 1 and the like has a bicycle shaft 60 supporting a wheel to which a protective cover 52 is attached as shown in FIG. Installed close together. The magnet 50 is attached to the spoke 61 at a height position where the coil 43 and the magnetic body 44 are attached from the wheel shaft.
Further, as shown in FIGS. 16 and 21, when the spoke 61 with the protective cover 52 attached is closest to the coil 43, the case 40 and the magnet 50 in which the coil 43 and the magnetic body 44 are stored are stored. It is desirable to design the gap L1 between the protective cover 52 and the protective cover 52 to be 1 mm to 5 mm.

  As an example of attachment of the protective cover 52 and the magnet 50 shown in FIG. 18, an example is shown in which one is attached to each of the two spokes 61, 61 that connect the wheel ring and the axle shaft. You may attach the protective cover 52, the magnet 50, and the board 51 to a spoke.

The operation of the bicycle light 111 configured as described above will be described.
The magnet 50 housed in the protective cover 52 rotates around the axle shaft as the wheel rotates, and moves circularly. As shown in FIG. 21, a case containing the coil 43 and the magnetic body 44 is accommodated. Cross the side of
At that time, the magnetic flux passing through the cylinders of the coil 43 and the magnetic body 44 changes. Thus, when one magnet 50 crosses the side of the case 40, an electromotive force is generated in the coil 43. Here, FIG. 22 is a graph showing an electromotive force generated when two protective covers 52 cross the side of the case 40. This electromotive force is supplied to the light source 1 to emit light. The light emitted radially from the light source 1 is collected by the bulk lens 20, and light with high illuminance is irradiated to the outside via the drip-proof cover 45.
Further, when the magnets 50 are attached to the plurality of spokes 61, the number of the magnets 50 that cross the side of the case 40 becomes plural as the wheel rotates, so that the electromotive force generated in the coil 43 is continuous as shown in FIG. become.

As described above, according to the bicycle light 111 according to the embodiment of the present invention, since the LED or the like is used as the light source 1, the power consumption can be reduced as compared with the light bulb, and therefore the generator can be reduced. Moreover, since the light emitted from the light source 1 is condensed by the bulk lens 20 and emitted to the outside, light with high illuminance can be obtained.
Furthermore, the bicycle light 111 is configured to supply an electromotive force based on a change in magnetic flux to the light source 1 as the power generation unit 30 by the coil 43, the magnetic body 44, and the magnet 50. Since there is no friction between the tire and the tire, the bicycle pedal can be stepped lighter than when the conventional roller is in contact with the tire.
In addition, since the power consumption of the light source 1 is 1/10 to 1/100 that of a light bulb, a generator having a simple structure including the coil 43, the magnetic body 44, and the magnet 50 as described above may be used. It can be configured with a simple structure.

Next, another embodiment of the present invention will be described.
In addition, since what shows the same code | symbol as used in said description is the same as the above, the description is abbreviate | omitted.
FIG. 24 is a diagram showing the internal structure of a bicycle light 112 according to another embodiment of the present invention. As shown in FIG. 24, the bicycle light 112 has a bulk lens 20, a coil 43, The magnetic body 44, the diode 71, the capacitor 72, and the control unit 73 are provided. The sensor 74 is short-circuited with the control unit 73, and the magnets 50 and 50 and the plate 51 are attached to the wheel spokes 61. .
In FIG. 24, the description of the circuit 41, the circuit board 42, the drip-proof cover 45, etc. shown in FIG. 17 is omitted, but the bicycle light 112 may be configured by incorporating them. 24 illustrates a case where the light source 1 and the bulk type lens 20 are provided one by one, but a plurality of the light sources 1 and bulk type lenses may be provided as shown in FIG.

  The diode 71 shown in FIG. 24 converts the alternating current sent from the coil 43 into a direct current, and the capacitor 72 converts the alternating current sent from the coil 43 into a direct current and supplies it to the light source 1. It is. The sensor 74 is a photosensor that detects natural light other than the light of the light source 1, and for example, a photodiode can be used. The control unit 73 performs control to send the voltage (current) supplied from the coil 43 to the light source 1 based on the signal from the sensor 74. For example, a signal is sent from a photodiode as the sensor 74. In this case, the voltage (current) from the coil 43 is not supplied to the light source 1. Specifically, when the sensor 74 detects natural light such as sunlight, the light source 1 does not emit light.

According to the bicycle light configured as shown in FIG. 24, by providing the diode 71, the light source 1 such as an LED can be reliably prevented from being damaged by an alternating current, and by providing the capacitor 72, An alternating current can also be used as energy for the light source 1 to emit light effectively. Further, by providing the sensor 74 and the control unit 73, the light can be switched on and off automatically.
Note that the bicycle light may be configured without the control unit 73 and the sensor 74, or may be configured without the control unit 73, the sensor 74, and the condenser 72.

In the above description, the case where the plurality of bulk lenses 20 provided in the bicycle lights 111 and 112 are separately provided is shown. However, as shown in FIG. The bulk type lens 20A may be used.
FIGS. 26A and 26B are front views showing a configuration example of the bulk type lens 20A according to the example of the present invention, respectively. The bulk type lens 20A shown in FIG. The mold lens 20 is radially formed and integrally formed. The bulk lens 20A shown in FIG. 26B is configured by integrally arranging three bulk lenses 20 in series.
Also by the bulk type lens 20A shown in FIGS. 26A and 26B, the light emitted from each light source 1 can be condensed and emitted to the outside.
The bicycle light shown in FIG. 25 can also be configured to sandwich the bulk type lens 20 </ b> A using an O-ring at the light exit of the case 40.
In addition to the above-described details, the present invention can be implemented in various forms without departing from the spirit of the invention.

It is a block diagram which shows the light for bicycles concerning embodiment of this invention. It is typical sectional drawing of the light source and bulk type lens which concern on embodiment of this invention. It is a figure which shows the condition of the loss by the lens system of a prior art. It is a figure which shows Fresnel reflection. It is a figure which shows the process in which reflected light (stray light) re-emits in the PN junction of LED. It is a figure which shows the measurement system used for the characteristic comparison with the 1st Example of the bulk type lens used for the bicycle light of this invention, and the conventional lens. It is the figure which compared the 1st Example of the bulk type lens used for the bicycle light of this invention, and the condensing characteristic of the conventional lens. It is the figure which compared the 1st Example of the bulk type lens used for the bicycle light of this invention, and the condensing characteristic of the conventional lens. It is a figure which shows the measured value of the characteristic change by the difference in the geometric shape of the bulk type lens used for the bicycle light of this invention. It is a figure which shows the geometric shape of the bulk type lens used for the measurement of FIG. It is sectional drawing which shows the structure of the 2nd Example of the bulk type lens used for the light for bicycles of this invention. It is a figure which shows the measured value of the characteristic change by the difference in the geometric shape of 2nd Example of a bulk type lens. It is a figure which shows the measured value of the characteristic change by the difference in the geometric shape of 2nd Example of a bulk type lens. It is a schematic diagram explaining the principle of the bulk type | mold lens which concerns on the 1st and 2nd modification. It is a figure which shows the structure of the bulk type lens which concerns on the 1st and 2nd modification. 1 is a perspective view showing a bicycle light according to an embodiment of the present invention. It is sectional drawing of FIG. It is a perspective view which shows the state which attached the bicycle light concerning the Example of this invention to the bicycle. It is a perspective view which shows the magnet which concerns on the Example of this invention. It is a perspective view which shows the attachment state of the magnet which concerns on the Example of this invention to the spoke of a wheel. It is a figure which shows the example of arrangement | positioning with the magnet and coil which concern on the Example of this invention. It is a graph which shows the electromotive force which occurred when two protective covers crossed the side of case 2 concerning the example of the present invention. It is a graph which shows the electromotive force which arises when the protective cover crosses the side of the case which concerns on the Example of this invention. It is a figure which shows the internal structure of the light for bicycles concerning the other Example of this invention. It is a fragmentary sectional view which shows the light for bicycles concerning the other Example of this invention. (A) And (B) is a front view which shows the structural example of the bulk type lens which concerns on the Example of this invention, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Ceiling part 3 Top part 4 Optical medium 5 Inner peripheral part 6 Recessed part 7 Bottom part 8 Spacer 9 Outer peripheral part 20 Bulk type lens 30 Power generation part 40 Case 40a Clamping part 41 Circuit 42 Circuit board 43 Coil 44 Magnetic body 50 Magnet 60 Bicycle axis 61 Spoke 71 Diode 72 Condenser 73 Control Unit 74 Sensor 100, 111, 112 Bicycle Light Using Bulk Lens

Claims (1)

A bulk type lens, a light source housed in the bulk type lens, and a power generation unit that supplies current to the light source based on an electromotive force generated by a change in magnetic flux of the magnet,
The bulk type lens is formed of an optical medium having a top, a bottom, an outer periphery, and a recess formed by a ceiling and an inner periphery formed from the bottom toward the top. Is a storage portion for the light source, the ceiling portion as a first lens surface, the inner peripheral portion as a light incident surface, the outer peripheral portion as a total reflection surface, the bottom portion as a reflection surface, and the top portion. Functions as a second lens surface, a bicycle light using a bulk lens.