Patent Application
20160025272
1. Field of the Invention
This embodiment relates to a lighting device capable of implementing rear light distribution.
2. Description of the Related Art
Here, related arts to the present invention will be provided and has not necessarily been to publicly known.
Nowadays, with the improvement of residential environment, indoor lighting is now being advanced from white lighting such as an existing fluorescent lamp, a halogen lamp or the like to luxurious interior lighting by representing indoor lighting colors, i.e., color temperatures in various ways. In particular, efforts are now being constantly made to representatively apply a light emitting diode (LED) light source device to the advanced interior lighting.
The LED has a small size and good efficiency and is capable of emitting light having an apparent color. Since the LED is a kind of a semiconductor device, the LED is less expected to be damaged, has excellent initial drive characteristic and impact-resistance, and is resistant to repetition like on/off lighting. For these reasons, the LED is now being widely used in various indicators and a variety of light sources. Moreover, R, G and B LEDs having ultra high luminance and high efficiency are now being developed respectively, and thus, a large-screen LED display using the LEDs is commercialized and widely used.
An angle at which light is emitted from a conventional LED lighting device is generally maintained from approximately 90° to 140°. Therefore, an interval at which a plurality of LEDs are disposed and mounted on a printed circuit board is set by the light emission angle. That is, the interval must be set such that the LEDs are densely disposed in order to prevent a dark zone from occurring due to the blocking of the light which is emitted from the LED and is incident on a light transmissive cover. Therefore, a fairly large number of the LEDs are required. Moreover, in order that the dark zone is removed by overlapping the light emitted from an LED with light emitted from another LED adjacent to the LED in a certain section, the light transmissive cover and the LED must be disposed at a large interval.
Accordingly, the conventional lighting device requires a large number of the LEDs and high manufacturing cost. The large interval between the light transmissive cover and the LED increases the thickness of the conventional lighting device, which makes the conventional lighting device become larger.
An embodiment of the present invention provides a lighting device capable of implementing rear light distribution.
The embodiment provides a lighting device capable of diffusing light at a beam angle (Lambertian 120°) of from 165° to 180°.
The embodiment provides a lighting device capable of removing a dark portion at a draft angle (14° to 16°) of a light source.
The embodiment provides a new structured lighting device capable of meeting U.S. Energy Star and ANSI specifications.
The embodiment provides a lighting device capable of obtaining a rear light distribution design technology for standardization.
The embodiment provides a lighting device capable of implementing rear light distribution characteristics by using a primary lens (e. g., a beam angle) 160°.
One embodiment is a lighting device including: a heat sink; a member which has a polygonal pillar shape having at least three sides and is disposed on the heat sink, wherein the sides are inclined at a predetermined angle toward the center of the heat sink; and a light source which is disposed on at least one among the sides of the member, wherein the light source includes: a substrate; at least two light emitting devices which are symmetrically disposed on the substrate with respect to the center of the substrate; and at least two lens units which are disposed on the light emitting devices respectively
Another embodiment is a lighting device including: a heat sink; a member which has a polygonal pillar shape having at least three sides and is disposed on the heat sink, wherein the sides are inclined at a predetermined angle toward the center of the heat sink; a light source which is disposed on at least one among the sides of the member and includes a substrate and at least two light emitting devices which are symmetrically disposed on the substrate with respect to the center of the substrate; and a lens unit including a lens disposed on the light emitting device. The lens includes a cylindrical side and a curved surface formed on the cylindrical side. The heat sink includes a top surface and a side which is inclined at a predetermined inclination angle on the basis of an imaginary line parallel with the top surface.
Arrangements and embodiments may be described in detail with reference to the following drawings in which like reference numerals refer to like elements and wherein:
a-16c show simulation results of the luminous intensity distribution of the conventional lighting device (
a-17c show simulation results of the luminous intensity distribution of the lighting device according to the embodiment (
A thickness or a size of each layer may be magnified, omitted or schematically shown for the purpose of convenience and clearness of description. The size of each component may not necessarily mean its actual size.
It should be understood that when an element is referred to as being ‘on’ or “under” another element, it may be directly on/under the element, and/or one or more intervening elements may also be present. When an element is referred to as being ‘on’ or ‘under’, ‘under the element’ as well as ‘on the element’ may be included based on the element.
An embodiment may be described in detail with reference to the accompanying drawings.
The lighting device according to the embodiment may include, as shown in
The cover 100 is disposed on the heat sink 300 and has an opening 110 formed in a lower portion thereof. The cover 100 has a bulb shape with an empty interior.
When the cover 100 is coupled to the heat sink 300, the light source 200 and a member 350 are inserted into the inside of the cover 100. Therefore, when the cover 100 is coupled to the heat sink 300, the light source 200 and the member 350 are surrounded by the cover 100.
Here, the cover 100 may be coupled to the heat sink 300 by using an adhesive or various methods, for example, rotary coupling, hook coupling and the like. In the rotary coupling method, the screw thread of the cover 100 is coupled to the screw groove of the heat sink 300. That is, the cover 100 and the heat sink 300 are coupled to each other by the rotation of the cover 100. In the hook coupling method, the cover 100 and the heat sink 300 are coupled to each other by inserting and fixing a protrusion of the cover 100 into the groove of the heat sink 300. Also, the cover 100 may include a plurality of projections (not shown). The heat sink 300 may include a plurality of recesses corresponding to a plurality of the projections.
A plurality of the projections are inserted into a plurality of the recesses of the heat sink 300 and have a shape suitable for being fastened to the recess. For example, a tip of the projection may have a trapezoidal shape for being fastened to the heat sink 300.
As such, the cover 100 may be disposed on the heat sink 300 and may have the opening 110 formed in the lower portion thereof. Also, the cover 100 may include an upper portion corresponding to the lower portion thereof, and a central portion between the lower portion and the upper portion. The diameter of the opening 110 of the lower portion may be equal to or less than that of the top surface of the heat sink 300. The diameter of the central portion may be larger than that of the top surface of the heat sink 300.
The cover 100 is optically coupled to the light source 200. In more detail, the cover 100 may diffuse, scatter or excite light emitted from a light emitting device (see reference number 220 of
The inner surface of the cover 100 may be coated with an opalescent pigment. Here, the opalescent pigment may include a diffusing agent diffusing the light.
The roughness of the inner surface of the cover 100 may be larger than that of the outer surface of the cover 100. This intends to sufficiently scatter and diffuse the light emitted from the light source 200.
The cover 100 may be formed of glass or a resin material such as plastic, polypropylene (PP), polyethylene (PE), polycarbonate (PC) and the like. Here, the polycarbonate (PC) has excellent light resistance, thermal resistance and rigidity.
The cover 100 may be formed of a transparent material causing the light source 200 and the member 350 to be visible to the outside or may be formed of an opaque material causing the light source 200 and the member 350 not to be visible to the outside. The cover 100 may be formed by a blow molding process.
The cover 100 may include a reflective material reflecting at least a part of the light emitted from the light source 200 toward the heat sink 300. A corrosion process may be performed on the inner surface of the cover 100. Moreover, a predetermined pattern may be applied on the outer surface of the cover 100. Due to the mentioned characteristics, the light emitted from the light source 200 may be scattered. Therefore, it is possible to prevent a user from feeling glare.
The light source 200 may be disposed on the member 350 disposed on the heat sink 300. More specifically, the light source 200 may be disposed on at least one of sides of the member 350. Here, the member 350 may have a polygonal pillar shape having sides which are inclined at a predetermined angle.
For example, the member 350 may have a side which is inclined at an angle from 14° to 16° toward the center of the heat sink 300. The member 350 may have any one of a polygonal pillar shapes including a triangular pillar, a square pillar, a hexagonal pillar and an octagonal pillar or may have a conical pillar shape. As such, the light source disposed on the side of the member diffuses the light through the cover, thereby improving the performance of rear light distribution.
In the lighting device, at least two light sources 200 may be disposed on the side of the member 350. The embodiment shows that the member 350 has a square pillar shape and the light source 200 is disposed on four sides of the member 350 respectively. However, there is no limit to this. The light source 200 may be disposed on a portion of the side of the member 350. The configuration of the member 350 will be described later in detail.
The light source 200 includes a substrate 210, at least one light emitting device (see reference number 220 of
Referring to
The member 350 is disposed on the top surface 310 of the heat sink 300. The top surface 310 is coupled to the cover 100. Here, the top surface 310 may have a shape corresponding to the opening 110 of the cover 100.
A plurality of heat radiating fins 370 may be disposed on the outer circumferential surface of the body 330 of the heat sink 300. At least a portion of the heat radiating fins 370 may have a side having a predetermined inclination. Here, the inclination may have a range more than 45° on the basis of an imaginary line parallel with the top surface of the heat sink 300.
The heat radiation fin 370 may be formed extending outwardly from the outer surface of the heat sink 300 or may be coupled to the outer surface of the heat sink 300. The heat radiating fin 370 having the described structure is able to improve heat radiation efficiency by increasing the heat radiating area of the heat sink 300.
In the mean time, for another example, the heat sink 300 may not include the heat radiation fin 370.
The heat sink 300 may have a receiver (not shown) receiving the circuitry 400 and the inner case 500.
The member 350 disposed on the top surface 310 of the heat sink 300 may be integrally formed with the top surface 310 of the heat sink 300 or may be coupled to the top surface 310 of the heat sink 300.
The member 350 may have a polygonal pillar shape or a conical pillar shape, each of which has a side which is inclined at a predetermined angle (e.g., 14° to) 16°. For example, the member 350 may have a square pillar shape. The square pillar-shaped member 350 has a top surface, a bottom surface and four sides. For another example, the member 350 may have a cylindrical pillar shape or an elliptical pillar shape as well as the polygonal pillar shape. When the member 350 has the cylindrical pillar shape or the elliptical pillar shape, the substrate 210 of the light source 200 may be a flexible substrate.
The light source 200 may be disposed on the side of the member 350. That is, the light source 200 may be disposed on all or some of the four sides. Also, at least two light sources 200 may be disposed on the side of the member 350. The embodiment shows that the light source 200 is disposed on all of the four sides.
The embodiment shows that the member 350 has a square pillar shape which has four sides inclined at a predetermined angle (e.g., 14° to 16°) toward the center of the heat sink. The light source 200 is disposed on the four sides respectively, thereby removing a dark portion at a draft angle of the light source 200. Further, a primary lens having a beam angle of from 165° to 180° is disposed on the light emitting device 220 of the light source 200, thereby improving rear light distribution characteristics.
The material of the member 350 may have thermal conductivity. This intends to rapidly radiate outwardly the heat generated from the light source 200. The material of the member 350 may include, for example, Al, Ni, Cu, Mg, Ag, Sn and the like and an alloy including these metallic materials. The member 350 may be also formed of thermally conductive plastic. The thermally conductive plastic is lighter than a metallic material and has a unidirectional thermal conductivity.
Referring to
The circuitry 400 is received within the heat sink 300. Specifically, the circuitry 400 is received in the inner case 500, and then is received, together with the inner case 500, in the receiver (not shown) formed in a lower inside of the heat sink 300.
The circuitry 400 may include a circuit board 410 and a plurality of parts 430 mounted on the circuit board 410. Here, the circuit board 410 may have a quadrangular plate shape. However, the circuit board 410 may have various shapes without being limited to this. For example, the circuit board 410 may have a circular plate shape, an elliptical plate shape or a polygonal plate shape. The circuit board 410 may be formed by printing a circuit pattern on an insulator.
The circuit board 410 is electrically connected to the substrate 210 of the light source 200. The circuit board 410 may be electrically connected to the substrate 210 by using a wire. That is, the wire is disposed within the heat sink 300 and may connect the circuit board 410 with the substrate 210.
The plurality of the parts 430 may include, for example, a DC converter converting AC power supply supplied by an external power supply into DC power supply, a driving chip controlling the driving of the light source 200, and an electrostatic discharge (ESD) protective device for protecting the light source 200.
Also, the inner case 500 receives the circuitry 400 thereinside. The inner case 500 may have a receiver 510 for receiving the circuitry 400. The receiver 510 may have a cylindrical shape. The shape of the receiver 510 may be changed according to the shape of the receiver (not shown) of the heat sink 300.
The inner case 500 is received within the heat sink 300. More specifically, the receiver 510 of the inner case 500 is received in the receiver (not shown) formed in the bottom surface (not shown) of the heat sink 300.
The inner case 500 is coupled to the socket 600. The inner case 500 may include a connection portion 530 which is coupled to the socket 600. The connection portion 530 may have a screw thread corresponding to a screw groove of the socket 600.
The inner case 500 may consist of a nonconductor. Therefore, the inner case 500 prevents electrical short-cut between the circuitry 400 and the heat sink 300. The inner case 500 may be made of a plastic or resin material.
Lastly, the socket 600 is coupled to the inner case 500. More specifically, the socket 600 is coupled to the connection portion 530 of the inner case 500.
The socket 600 may have the same structure as that of a conventional incandescent bulb. The circuitry 400 is electrically connected to the socket 600. Here, the circuitry 400 may be electrically connected to the socket 600 by using a wire. Therefore, when external electric power is applied to the socket 600, the external electric power may be supplied to the circuitry 400 through the socket 600, and then the electric power converted by the circuitry 400 is supplied to the light source 200. The socket 600 may have a screw groove corresponding to the screw thread of the connection portion 530.
As described above, the lighting device according to the embodiment is capable of meeting U.S. Energy Star and ANSI specifications and of remarkably improving rear light distribution characteristics and removing the dark portion by disposing the member 350 of which the side is inclined at a predetermined angle (14° to 16°) on the heat sink 300, by disposing the light source 200 on the side of the member 350, and by disposing the lens unit 230 having a beam angle of from 165° to 180° on the light emitting device 220 of the light source 200.
A Configuration Example of Light Source
As shown in
The light source 200 may further include the lens unit 230 disposed on the light emitting device 220 of the substrate 210. Here, the lens unit 230 may have a beam angle of from 165° to 180° and may be composed of an aspheric lens 231.
As shown in
The lens 231 having the described configuration increases an orientation angle of the light emitted from the light emitting device 220, and thus improves the uniformity of a linear light source of the lighting device.
Meanwhile, the lens unit 230 may have optimized data as follows.
Referring to
Also, a reflective layer (not shown) may be formed on the bottom surface 232 of the lens unit 230. Here, the reflective layer may be formed of at least any one selected from the group consisting of metallic materials including Al, Cu, Pt, Ag, Ti, Cr, Au and Ni by deposition, sputtering, plating, printing or the like methods in the form of a single or composite layer.
The substrate 210 disposed under the lens unit 230 has a quadrangular plate shape. However, the lens unit 230 may have various shapes, for example, a circular shape, a polygonal shape and the like without being limited to the quadrangular plate shape.
The substrate 210 may be formed, for example, to have a size of 10×10×1.7 mm. Here, a chip size of the light emitting device 220 may have a size of 1.3×1.3×0.1 mm.
The substrate 210 may be formed by printing a circuit pattern on an insulator. For example, the substrate 210 may include a common printed circuit board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB and the like. Also, the substrate 210 may include a chips on board (COB) allowing an LED chip to be directly bonded to a printed circuit board. The substrate 210 may be formed of a material capable of efficiently reflecting light. The surface of the substrate 210 may have a color (for example, white, silver and the like) capable of efficiently reflecting light. The surface of the substrate 210 may be formed of a material capable of efficiently reflecting light. The surface of the substrate 210 may be coated with a color capable of efficiently reflecting light (for example, white, silver and the like). For example, the surface of the substrate 210 may have a reflectance greater than 78% with respect to light reflected by the surface of the substrate 210.
Referring to
The light emitting device 220 may be a light emitting diode chip emitting red, green and blue light or may be a light emitting diode chip emitting UV. Here, the light emitting diode chip may have a lateral type or vertical type and may emit blue, red, yellow or green light.
The light emitting device 220 may have a fluorescent material. The fluorescent material may include at least any one selected from the group consisting of a garnet material (YAG, TAG), a silicate material, a nitride material and an oxynitride material. Otherwise, the fluorescent material may include at least any one selected from the group consisting of a yellow fluorescent material, a green fluorescent material and a red fluorescent material.
In the embodiment, the light emitting device 220 has a size of 1.3×1.3×0.1 mm. An LED chip including the blue LED and the yellow fluorescent material is used as the light emitting device 220. Here, the scattering of the LED chip is greater than 92% and Lambertian larger than 120° can be obtained.
Simulation Result of Lens
First, referring to
As shown in the graph of
As shown in the color coordinate of
U.S. Energy Star and ANSI Specifications
American National Standards Institute (ANSI) specifications have previously specified norms or standards for U.S. industrial products. ANSI specifications also provide standards for products like the lighting device of the embodiment.
For the purpose of meeting ANSI specifications, the lighting device according to the embodiment may be designed such that a ratio of the overall height of the lighting device, the height of the cover 100, the diameter of the cover 100, the diameter of the lower portion of the cover 100, the size of the lower portion of the member 350, the size of the upper portion of the member 350 and the thickness of the cover 100 is 46.5˜47.5:24˜25:30˜31:20˜21:13.5˜14.5:6.6˜7.5:1.
For example, referring to
U.S. Energy Star stipulates that a lighting device or a lighting apparatus should have a predetermined luminous intensity distribution.
Particularly, referring to the Energy Star shown in
Through the following simulation result, it can be found that the lighting device according to the embodiment is able to meet the Energy Star shown in
Simulation Result
As shown in the color coordinate of
In comparison with the conventional lighting device, regarding the lighting device according to the embodiment as shown in the color coordinate of
Through the color coordinate result, it can be appreciated that the Flux ratio between 135° and 180° of the lighting device according to the embodiment is increased as compared with that of the conventional lighting device.
According to the simulation results of
Through a comparison of the simulation results of
Therefore, the lighting device according to the embodiment shows that the rear light distribution characteristics required by the U.S. Energy Star is remarkably improved. Also, it can be seen through the simulation result that the existing dark portion is greatly reduced. The following table shows the simulation result (standardization) of the embodiment.
The through the simulation result of the embodiment, it is found that when the conditions such as the shape of the member 350, the location of the light source 200, the draft angle and the like are met, the U.S. Energy Star and the ANSI specifications are met.
In the lighting device according to the embodiment configured as such, the member of which the side is inclined at a predetermined angle is disposed on the heat sink in such a manner as to meet U.S. Energy Star and ANSI specifications, the light source is disposed on the side of the member, and the lens is disposed on the light emitting device of the light source, so that the technical problems of the present invention can be overcome.
Although embodiments of the present invention were described above, these are just examples and do not limit the present invention. Further, the present invention may be changed and modified in various ways, without departing from the essential features of the present invention, by those skilled in the art. For example, the components described in detail in the embodiments of the present invention may be modified. Further, differences due to the modification and application should be construed as being included in the scope and spirit of the present invention, which is described in the accompanying claims.
Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to affect such feature, structure, or characteristic in connection with other ones of the embodiments.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2012-0009699 | Jan 2012 | KR | national |
This application is a Continuation application of prior U.S. application Ser. No. 13/754,676 filed Jan. 30, 2013, which claims priority under 35 U.S.C. §119 to Korean Application No. 10-2012-0009699 filed on Jan. 31, 2012, whose entire disclosures are incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13754676 | Jan 2013 | US |
| Child | 14812843 | US |
