JP6126785B2 - LED bulb - Google Patents

Description

  The present invention relates to an LED bulb.

  LED bulbs have rapidly become popular in recent years because they have the advantages of lower power consumption and longer product life compared to incandescent bulbs and fluorescent lamps. Recently, various studies have been made to irradiate light emitted from LEDs in a form according to the purpose. For example, Patent Document 1 aims to enable uniform illumination around a button with a compact configuration. As an LED lens structure, a light reflecting surface is provided on the bottom surface of the button, and a light receiving surface for receiving reflected light from the reflecting surface is provided on a ring-shaped lens body. Further, Patent Document 2 aims to guide light emitted from an LED light source in a desired direction without loss and to intensively radiate light onto an object. LED lamps are proposed. In addition, in Patent Document 3, in a lighting fixture using an LED element, a light-shielding mask or light is applied to a bowl-shaped lens arranged in the vicinity of a light emitting portion of an LED for the purpose of improving illumination with a substantially circular irradiation range. A lighting fixture provided with a diffusion portion has been proposed.

JP 2010-198755 A JP 2004-356512 A JP 2011-134509 A

  By the way, when the lighting fixture using a general light bulb is applied to an LED light bulb as it is, there may arise a problem that glare or shadow occurs. As a result of paying attention to this problem, the present inventors have found that a difference between a light distribution curve of a general light bulb and a light distribution curve of an LED light bulb causes such a problem. Below, the light distribution curve of the conventional LED bulb is demonstrated. 10A and 10B are diagrams showing a light distribution curve of a conventional LED bulb, where FIG. 10A is a daylight white color, and FIG. 10B is a light bulb color light distribution curve. FIGS. 10A and 10B show the luminous intensity (cd) in the 360-degree direction when the light emission direction from the light source (vertical downward in the figure) is 0 degree. Neither daylight white nor the color of the light bulb has obtained almost any light intensity behind the horizontal direction (90 to 270 degrees) with respect to the light emission direction, that is, on the upper side in the figure.

  FIG. 11 is a diagram comparing the light distribution curves of a conventional LED light bulb and a general light bulb. (A) shows a light distribution curve of a single light bulb, and (B) shows a state in which the light bulb is attached to a lighting fixture. It represents a light distribution curve. As shown in FIG. 11A, the two types of LED bulbs emit light only in front of the light source, whereas the general bulbs are behind the light source (90 degrees to 180 degrees to 90 degrees). It also emits light and shows a heart-shaped light distribution curve.

  When an LED bulb having a light distribution curve as described above is attached to a lighting fixture, as shown in FIG. 11B, the light is reflected by the reflector of the fixture, only in front of the light source, and by the fixture. It emits light within a limited range. Based on the difference in the light distribution curve between the LED bulb and the general bulb, the present inventor has created an LED bulb showing a light distribution curve similar to that of a general bulb, and has excellent light emission characteristics that hardly cause glare and shadows. It was thought that the LED lighting fixture which has can be provided. However, an LED bulb having a heart-shaped light distribution curve like a general bulb is not known at all.

  This invention is made | formed in view of such a condition, and makes it a main subject to provide the LED light bulb which has the outstanding light emission characteristic which a glare and a shadow are hard to generate | occur | produce.

The present invention for solving the above-described problems is an LED light bulb, which is an LED light emitter and is formed in a solid cylindrical shape, and has a light distribution in which one end in the axial direction is disposed close to the LED light emitter. The light distribution means has a recess formed at the other end and a light distribution section on the side surface, and the depth of the recess is larger than the diameter of the light distribution means, and the light distribution The part is provided continuously from the end face of the other end side of the light distribution means to the one end side from a position slightly lower than the depth of the recess.

  Moreover, the light distribution part may be a light distribution film wound around a side surface of the light distribution means. Moreover, the said light distribution part may be comprised by forming the side surface of the said light distribution means in the shape of ground glass.

Moreover, the said recessed part may be formed so that a curvature radius may become small as it goes to a bottom part from an edge part. Moreover, the one end of the said light distribution means may be formed in the plane, may be formed in convex shape, and may be formed in concave shape.

  According to the present invention, although it is an LED light bulb, it has a light distribution curve similar to that of a general light bulb. In addition to the advantages of the conventional LED light bulb, the LED light bulb has excellent luminous characteristics that are less likely to cause glare and shadows. Can be provided.

It is a schematic diagram which shows one Embodiment of this invention. It is sectional drawing of the LED bulb of FIG. It is an expanded sectional view of the front-end | tip part of the LED bulb of FIG. It is a light distribution curve of the LED bulb which is one Embodiment of this invention. It is a light distribution curve of the LED bulb which is other embodiment of this invention. It is a light distribution curve of the LED bulb which is other embodiment of this invention. (A) is the schematic which shows the method of a total light beam measurement, (B) is a figure which shows the measurement result of the total light beam of the LED bulb of FIGS. It is typical sectional drawing of 2nd Embodiment of this invention. It is typical sectional drawing of 3rd Embodiment of this invention. It is a figure which shows the light distribution curve of the conventional LED bulb. It is the figure which compared the light distribution curve of the conventional LED light bulb and a general light bulb.

  Hereinafter, embodiments of the LED bulb of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the LED bulb 10 of FIG. The LED bulb 10 shown in the figure has an LED light emitter 12, a socket 14, and a light distribution means 16.

  In this embodiment, the LED light emitter 12 is a plate-shaped member in which a plurality of LED elements are arranged and fixed with silicon resin or the like, and emits light from a plane in a substantially vertical direction.

  As the socket 14, a conventionally known one having a power supply unit to the LED light emitter 12 and an attachment unit for attaching the LED bulb 10 to the installation location can be used. When the LED illuminant 12 having a large wattage is used, the socket 14 preferably has a large number of fins and a high cooling effect.

  Further, as shown in FIG. 2, a heat sink 15 (heat radiator 15) is preferably provided above the LED light emitter 12. According to this configuration, it is possible to prevent the temperature in the socket 14 from rising due to heat generated from the LED light emitter 12. The shape of the heat sink 15 is not particularly limited, but considering the heat radiation performance, it is preferable that the heat sink 15 has a large surface area, and a plate generally called a fin, a sword mountain shape, or a bellows shape is suitable. Can be used.

  As a material of the heat sink 15, a material having good thermal conductivity is preferable, and for example, aluminum, copper, or the like can be preferably used.

  Further, when the LED illuminator 12 having a large wattage is used, it is preferable to install a cooling fan 17 for the LED illuminant 12 inside the socket 14 instead of or together with the heat sink 15 described above. By installing the cooling fan 17 inside the socket 14, even when the LED illuminant 12 having a large wattage is used, the inside of the socket 14 can be kept at a constant temperature, and the inside of the socket becomes high temperature. As a result, it is possible to prevent damage to the socket 14, the power supply unit, the light distribution means 16, and the like.

  The cooling fan can be appropriately installed at a position where the temperature inside the socket can be kept constant, and the installation location is not particularly limited. As a preferred embodiment, a configuration in which a heat sink 15 is provided above the LED light emitter 12 and a cooling fan 17 is provided above the heat sink 15 as shown in FIG.

  The light distribution means 16 is formed of a member that is formed in a solid cylindrical shape and has a light transmitting property. As shown in FIG. 2, the light distribution means 16 has a light source side end portion 18 that is one end in the axial direction thereof, which emits LED. It arrange | positions so that the body 12 may be faced, and is being fixed to the socket 14 with the volt | bolt etc. which are not shown attached to the flange part 22. FIG. Moreover, in the form shown in figure, the LED light-emitting body 12 has taken the structure fixed to the flange part 22. As shown in FIG. The light output side end 20, which is the other end of the light distribution means 16, protrudes outside the socket 14, and the cylindrical portion of the light distribution means 16 extends outside the socket 14. In the illustrated form, the light source side end portion 18 of the light distribution means 16 has a configuration that does not protrude the flange portion 22, but is disposed so that the light source side end portion 18 faces the LED light emitter 12, If it is comprised so that the light emitted from LED light-emitting body 12 may pass through the inside of a cylindrical part, it will not be limited to this structure. For example, the light source side end portion 18 of the light distribution means 16 may pass through the flange portion 22 and protrude in the inner direction of the socket 14.

  As the member of the light distribution means 16, a conventionally known member having light permeability can be appropriately selected and used. Examples of such a member include acrylic resin, polycarbonate, and glass. In particular, the acrylic resin can be preferably used as a member of the light distribution means 16 in that the refractive index is large. A resin such as an acrylic resin or polycarbonate is preferable because it is easy to mold and process and is lightweight.

  The light distribution means 16 has a diameter that covers the light emitting area of the LED light emitter 12. The diameter of the light distribution means 16 is not particularly limited as long as it has this requirement, but the light distribution means 16 should have a diameter of about 1 to 1.5 times the light emission area of the LED light emitter 12. preferable. By setting the diameter of the light distribution means 16 within this range, even when the LED light emitter 12 is small, a large area can be effectively emitted.

  In this embodiment, the diameter of the cylindrical portion (the portion excluding the flange portion 22) of the light distribution means 16 is φ20 mm with respect to the LED light emitter 12 of □ 18 mm. It shows an example and is not limited to this form.

  The shape of the light source side end 18 of the light distribution means 16 is not particularly limited and may be any shape. In one embodiment of the present invention, the light source side end 18 is formed in a substantially flat surface.

  In the present invention, the light output side end 20 of the light distribution means 16 is formed with a recess 24. FIG. 3 shows an enlarged cross-sectional view in the vicinity of the light output side end 20 of the light distribution means 16. The recess 24 is a curved surface having a curvature that decreases from the edge toward the bottom, and has a so-called half egg shape. A portion near the edge of the recess 24 has a large curvature and is close to a taper. By making the concave portion 24 a curved surface instead of a cone, it is possible to alleviate the unevenness of the emitted light from being concentrated in the central portion. The curvature of the bottom part of the recessed part 24 can be set suitably within the range which has the said effect, and is not limited about the curvature of the bottom part of the recessed part 24. FIG.

  In one embodiment of the present invention, the diameter of the light distribution means 16 is 20 mm, whereas the curvature of the bottom of the recess 16 is 16 mm in diameter, but this is not a limitation.

  The relationship between the diameter d of the light distribution means 16 and the depth h of the recess 24 shown in FIG. 3 is not particularly limited, but from the viewpoint of improving the emission efficiency, the depth h of the recess 24 is determined by the light distribution means. It is preferably larger than the diameter d of 16. A particularly preferable ratio h / d between the depth h of the recess and the diameter d of the light distribution means 16 is about 1.1 to 1.25.

  The surface of the recess 24 may be a transparent surface, but the surface is preferably formed in a ground glass shape. Or it is good also considering the surface of the recessed part 24 as a silver surface by giving a silver coating. By making the surface of the recess 24 into a ground glass shape or applying a silver paint, the reflectance can be increased compared to a transparent surface. In addition, when the surface of a recessed part is made into the shape of ground glass, a reflectance can be about 50 to 80%. In addition, when silver coating is applied to the surface of the recess, the reflectance can be almost 100% depending on the thickness of the coating.

  A light distribution unit 26 is provided on the side surface of the light distribution means 16, that is, on the cylindrical surface. By providing the light distribution unit 26 on the cylindrical surface, the light from the LED light emitter 12 incident on the light distribution unit 16 is diffusely reflected by the light distribution unit 26 while traveling in the optical axis direction through the light distribution unit 16. A part of the light is emitted from the light output side end 20 of the light distribution means 16 and a part of the light is transmitted through the light distribution part 26 and emitted from the cylindrical surface of the light distribution means.

  As shown in FIGS. 1 and 3, the light distribution unit 26 is provided continuously from the position lower than the end face of the light output side end 20 of the light distribution means 16 by a predetermined distance t from the light source side end 18. . In order to obtain a larger amount of light, the interval t is preferably slightly larger than the depth h of the concave portion 24 of the light output side end portion 20, as shown in FIG.

  The light distribution unit 26 may be any unit that exhibits the above-described effects. For example, the light distribution unit 26 that exhibits the above-described effect by winding a light distribution film capable of transmitting light around the side surface of the light distribution unit 16. It can be.

  The light distribution film that forms the light distribution section 26 may be any film that is in close contact with the light distribution means 16 through the adhesive layer and can transmit light. As such, a white tape can be used. In addition to this, a light distribution film can be formed on the side surface of the light distribution means 16 by thinly coating a rubber-based material. However, in terms of making the film thickness more uniform, it is preferable to apply a white tape or the like rather than a coated film, and good light emission characteristics can be obtained.

  There is no particular limitation on the number of tape windings and the coating amount when the white tape or rubber-based material is applied, but the light distribution film is within a range in which the light transmittance after forming the light distribution film is about 20 to 30%. Preferably it is formed.

  As another example of the light distribution unit 26, the light distribution unit 26 can be formed by processing the side surface of the light distribution unit 16 into a glass shape. When the light distribution part 26 is made of ground glass, the light emission tends to be weaker than when the above-described light distribution film is formed.

  The material of the flange portion 22 is not particularly limited and any conventionally known material can be used. However, when the same material as the light distribution means 16 is used as the material of the flange portion 22, that is, light is transmitted. When a material that can be used is used, it is preferable to provide a light distribution portion similar to the above on the side surface (cylindrical surface) of the flange portion 22. Note that this processing is not necessary when a plastic or the like that cannot transmit light is used as the material of the flange portion 22.

  Next, the light emission characteristic of the LED bulb 10 that satisfies the above-described invention-specific matters of the present invention will be described. 4 to 6 show light distribution curves of the LED bulb 10. 4 shows a light distribution unit 26 in which a white tape (E-SD manufactured by Nitto Denko Co., Ltd.) is closely attached to the side surface of the light distribution unit 16 in a single roll. It is a measurement result of the luminescent property of what coated the surface of the recessed part 24 provided in 20 in silver (LED lamp No. 1). FIG. 5 shows the measurement results of the light emission characteristics when the surface of the recess 24 in FIG. 4 is changed to a clear one (LED lamp No. 2). FIG. 6 is a measurement result of the light emission characteristics when the surface of the recess 24 is changed to a ground glass shape (LED lamp No. 3) in FIG. In all of FIGS. 4 to 6, the light intensity was obtained behind the light source, and a substantially heart-shaped light distribution curve was obtained. In addition, the transmittance | permeability of light when a white tape (E-SD Nitto Denko Co., Ltd. product) is closely_contact | adhered by single winding is about 30%.

  7A is a schematic diagram illustrating a method of measuring the total luminous flux of the LED bulb 10, and FIG. 7B is a measurement of the total luminous flux of the LED lamps No. 1 to No. 3 in FIGS. It is a table | surface which shows a result. As shown in the figure, the total luminous flux of LED lamp No. 1 is 1660 (lm), the total luminous flux of LED lamp No. 2 is 1710 (lm), the total luminous flux of LED lamp No. 3 is 1950 (lm), The largest value was obtained in LED lamp No. 3 in which the surface of the concave portion 24 was made into a glass shape.

  Thus, the LED light bulb 10 of the present invention exhibits a substantially heart-shaped light distribution curve having bulges on the left and right sides behind the light source, which is similar to the light distribution curve of a general light bulb. That is, the LED bulb 10 according to the present invention is irradiated rearward like a general bulb, and the irradiation angle is wider than that of a conventional LED lamp. Therefore, when attached to the instrument, there is an advantage that the front irradiation is amplified by the front irradiation and the irradiation using the reflector from the rear. 4 to 6, the LED bulb 10 of the present invention has light distribution in the 90-degree direction (horizontal direction of the light source), so that the LED bulb 10 alone can be used as the entire illumination.

  The illuminance on the plane can be calculated by the following formula (1).

  In the above-described example, the light source side end 18 of the light distribution means 16 is substantially flat, but as another embodiment, as shown in FIG. 8, the light distribution means 16 of the LED bulb 10a has a light source side end 18a. May be convex. Thereby, the light source side end portion 18a acts as a convex lens, and can be efficiently condensed. FIG. 8 is an enlarged cross-sectional view showing an example of the vicinity of the light source side end.

  Alternatively, as shown in FIG. 9, the light distribution means 16 of the LED bulb 10b may have a light source side end portion 18b having a concave shape. FIG. 9 is an enlarged cross-sectional view showing an example of the vicinity of the light source side end.

  In addition, in the said embodiment, although the plate-shaped thing is used as the LED light-emitting body 12, this invention is not limited to this, Other shapes, for example, a bullet-shaped thing, can also be used. In the case of a bullet-shaped LED illuminator, the light emission angle is narrower and the directivity is higher than that of a flat plate-shaped one, so that the shape of the light source side end 18 of the light distribution means 16 is concave as shown in the example of FIG. The light is preferably formed in a shape so that light incident on the light distribution means 16 is diffused.

  The shape of the light source side end 18 may be appropriately selected so as to obtain a desired light distribution characteristic in accordance with the form of the LED light emitter and the form of other parts.

  Although the LED bulb of the present invention has been described in detail above, the present invention is not limited to this, and various modifications can be made without departing from the spirit of the present invention.

10, 10a, 10b LED bulb 12 LED light emitter 14 Socket 15 Heat sink 16 Light distribution means 17 Cooling fans 18, 18a, 18b Light source side end 20 Light output side end 22 Flange 24 Recess 26 Light distribution

Claims (7)

An LED emitter;
It is formed in a solid cylindrical shape, and has a light distribution means in which one end in the axial direction is disposed close to the LED light emitter,
The light distribution means has a concave portion at the other end and a light distribution portion on the side surface.
The depth of the recess is larger than the diameter of the light distribution means,
The LED light bulb is characterized in that the light distribution part is continuously provided from the end surface on the other end side of the light distribution means to the one end side from a position slightly lower than the depth of the recess. . The LED bulb according to claim 1,
The LED light bulb, wherein the light distribution part is a light distribution film wound around a side surface of the light distribution means. The LED bulb according to claim 1 or 2,
The said light distribution part is comprised by the side surface of the said light distribution means being formed in the shape of a ground glass, The LED light bulb characterized by the above-mentioned. In the LED bulb according to any one of claims 1 to 3,
The LED light bulb, wherein the concave portion is formed such that a radius of curvature decreases from an edge portion toward a bottom portion. The LED bulb according to any one of claims 1 to 4,
One end of the light distribution means is formed in a flat surface. In the LED bulb according to any one of claims 1 to 5,
One end of the light distribution means is formed in a convex shape. In the LED bulb according to any one of claims 1 to 5,
One end of the light distribution means is formed in a concave shape.