WO2009154321A1

WO2009154321A1 - Led fluorescent lamp

Info

Publication number: WO2009154321A1
Application number: PCT/KR2008/004277
Authority: WO
Inventors: Jung-Seok Park
Original assignee: Msm Tech Co., Ltd.
Priority date: 2008-06-16
Filing date: 2008-07-22
Publication date: 2009-12-23
Also published as: JP2009302028A; KR100907310B1

Abstract

Provided is an LED fluorescent lamp comprising a circuit board on which light-emitting diodes (LED) are arranged and fixed at regular intervals; an LED driving means attached to a lower part of the circuit board and adapted to turn on/off the LEDs in response to signals being input from the outside; a diffusion cover provided on an upper part of the circuit board and diffusing the light emitted from the LEDs; a semi-cylindrical heat sink cover connected to the diffusion cover to form a fluorescent-type tube and having a plurality of heat sink fins formed on the outer periphery thereof; electrical connection means fitted to be connected to both ends of the combined diffusion cover and heat sink cover and outputting an LED-driving power supply to the LED driving means; and a finishing cap connected to an upper part of the electrical connection means and adapted to isolate the electrical connection means from the external environment, wherein the finishing cap is provided with a pair of power supply pins in electrical connection with the electrical connection means. Therefore, the present invention enables effective cooling of heat generated in LED devices and overcomes disadvantages associated with light directionality and rectilinearity of an LED light source.

Description

LED FLUORESCENT LAMP

Technical Field

[1] The present invention relates to an LED fluorescent lamp. More specifically, the present invention relates to an LED fluorescent lamp which is capable of being easily used as an alternative to a currently available fluorescent lamp, through fabrication of a lamp using a light-emitting diode (LED) as a light source, in the form of a fluorescent lamp with conventional shape and dimensions.

[2]

Background Art

[3] Fluorescent lamps are light sources that have been widely used for a long time not only in signboard industries but also in lighting industries, because they are easily available from conventional supermarket stores or electrical and electronic repair shops, are inexpensive, and can also be easily installed without particular difficulty.

[4] However, the fluorescent lamps have various shortcomings such as need for frequent replacement due to the occurrence of black spots on the glass envelope and a short lifespan, limited design in colors and shapes, and use of fluorescent materials going against the trend of the lighting market seeking environmental friendliness. For these reasons, the fluorescent lamps are gradually being replaced with alternative light sources.

[5] One of the alternative light sources that lately is drawing the most attention is a light emitting diode (LED). With success in commercialization of red LEDs using a GaAsP semiconductor in 1962, GaAsP LEDs in conjunction with GaP:N green LEDs have been conventionally used as display light sources for electronic devices including information communication equipment.

[6] Further, full-color displays were realized with development of GaN green LEDs in the mid- 1990' s.

[7] LEDs may be used for various applications, such as liquid crystal display devices of mobile phones, keypad backlights, large electric bulletin boards for outdoor installation, traffic signal lamps, instrument panels and tail lights of motor vehicles, and warning and guide lights for harbors and bays, airports, and multistoried buildings.

[8] Further, LEDs are receiving a great deal of interest as a next-generation national strategic item because they exhibit advantages such as rapid processing speed and lower power consumption intrinsic to semiconductors, and high energy saving effects in conjunction with environmental friendliness.

[9] In addition, LEDs have a variety of excellent strengths such as feasibility of compact and small-sized construction, lower power consumption, 10-fold longer lifespan, and rapid response speed, as compared to conventional light sources such as traditional light bulbs. In addition, LEDs do not emit harmful waves such as UV rays, and are environmentally friendly due to no use of mercury (Hg) and other discharge gases.

[10] However, LEDs release energy in the form of heat as well as light, which consequently results in high susceptibility to a high temperature state. In order to cool the high temperature state of the device, some attempts have been made using an electric lamp with provision of a through-hole at the outside of an LED lamp. However, efficiency of the LED lamp having such a structure significantly decreases due to an inflow of dust or other harmful insects via the through-hole. Further, an LED lifespan may decrease due to exposure of the device to high temperature conditions resulting from internal heat generation of the device. To this end, intensive and extensive studies and experiments have been continuously attempted to cool heat generation of LEDs.

[11] Further, LED-emitted light exhibits directionality, so the region just below the LED is correspondingly very bright, but the surrounding therearound is relatively dim. For this reason, when it is intended to use an LED light source for conventional electric lamps, there is a need for a separate device which is capable of diffusing high-directivity light emitted from the LED

[12]

Disclosure of Invention

Technical Problem

[13] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an LED fluorescent lamp which is designed to be capable of effectively removing heat generated in a light-emitting diode (LED), by configuring a portion of an outer case for isolation of the LED from the external environment into a heat sink member, upon fabrication of a fluorescent-type lamp using an LED as a light source.

[14] It is another object of the present invention to provide an LED fluorescent lamp which is designed to be capable of previously removing an afterimage phenomenon of the LED due to spontaneous diffusion of LED-emitted light even without provision of a separate diffusion plate or diffusion film, through the fabrication of a cover capable of isolating an LED light source from the outside, using a material member containing a diffusion material.

[15] It is yet another object of the present invention to provide an LED fluorescent lamp which is capable of achieving easy assembly by configuring it to have a structure such that an end of a heat sink cover and an end of a diffusion cover can be fitted to be connected to each other by force applied from the outside. [16]

Technical Solution

[17] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of an LED fluorescent lamp comprising: [18] a circuit board on which light-emitting diodes (LED) are arranged and fixed at regular intervals; [19] an LED driving means attached to a lower part of the circuit board and adapted to turn on/off the LEDs in response to signals being input from the outside; [20] a diffusion cover provided on an upper part of the circuit board and diffusing the light emitted from the LEDs; [21] a semi-cylindrical heat sink cover combined to the diffusion cover to form a fluorescent-type tube and having a plurality of heat sink fins formed on the outer periphery thereof; [22] electrical connection means fitted to be connected to both ends of the combined diffusion cover and heat sink cover and outputting an LED-driving power supply to the

LED driving means; and [23] a finishing cap connected to an upper part of the electrical connection means and adapted to isolate the electrical connection means from the external environment, [24] wherein the finishing cap is provided with a pair of power supply pins in electrical connection with the electrical connection means. [25]

Advantageous Effects

[26] As illustrated hereinbefore, the present invention is capable of achieving effective removal of LED-generated heat, by configuring a portion of an outer case for isolation of the LED from the external environment into a heat sink member, upon fabrication of an LED fluorescent lamp.

[27] Further, the present invention is capable of achieving previous removal of an afterimage phenomenon of the LED due to spontaneous diffusion of LED-emitted light even without provision of a separate diffusion plate or diffusion film, through the fabrication of a cover capable of isolating an LED light source from the outside, using a material member containing a diffusion material.

[28] Further, the present invention is capable of achieving easy assembly of a device by configuring it to have a structure such that an end of a heat sink cover and an end of a diffusion cover can be fitted to be connected to each other by force applied from the outside.

[29]

Brief Description of Drawings [30] FIG. 1 is a perspective view of an LED fluorescent lamp in accordance with one embodiment of the present invention; [31] FIG. 2 is a cross-sectional view of an LED fluorescent lamp in accordance with one embodiment of the present invention; [32] FIG. 3 is a partial view of a circuit board in accordance with one embodiment of the present invention; and [33] FIGS. 4 and 5 are views illustrating the spacing between light-emitting diodes

(LEDs) which are applied to the present invention. [34]

Mode for the Invention [35] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. [36] FIG. 1 illustrates an LED fluorescent lamp to which the present invention is applied.

Referring to FIG. 1, an LED fluorescent lamp 100 is structurally configured such that a heat sink cover 20 is positioned above a diffusion cover 30, and the diffusion cover 30 is fitted to be connected to the heat-sink cover 20 by externally applied force. [37] Accordingly, the LED fluorescent lamp in accordance with the present invention has the same shape as a conventional fluorescent lamp, and can be installed in the same manner as the conventional fluorescent lamp, by connecting power supply pins 43 of the LED fluorescent lamp 100 to connection terminals for a fluorescent lamp that were previously installed.

[38] The LED fluorescent lamp will be described with reference to FIGS. 2 and 3.

[39] In one embodiment of the present invention, the LED fluorescent lamp includes:

[40] a circuit board 15 on which light-emitting diodes (LED) 10 are arranged and fixed at regular intervals; [41] an LED driving section 17 attached to an upper part of the circuit board 15 and adapted to turn on/off the LEDs 10 in response to signals being input from the outside; [42] a diffusion cover 30 provided on a lower part of the circuit board 15 and diffusing the light emitted from the LEDs 10; [43] a semi-cylindrical heat sink cover 20 connected to the diffusion cover 30 to form a fluorescent-type tube and having a plurality of heat sink fins formed on the outer periphery thereof; [44] electrical connection parts 50 fitted to be connected to both ends of the combined diffusion cover 30 and heat sink cover 20 and outputting an LED-driving power supply to the LED driving section 17; and [45] a finishing cap 40 connected to an upper part of the electrical connection part 50 and adapted to isolate the electrical connection part 50 from the external environment. [46]

[47] As shown in FIG. 5, the spacing between LEDs 10 arranged and fixed on the circuit board 15 is determined such that the light emitted from a given number of LEDs 10 overlaps one another by a light-emitting angle of the LEDs 10.

[48] As shown in FIG. 5, the distance between the circuit board 15 and the diffusion cover

30 is also determined such that the light emitted from the LEDs 10 inside the diffusion cover 30 overlaps one another. The diffusion cover 30 also has a semi-cylindrical shape similar to the heat sink cover 20, and therefore has a tube-like shape as in a conventional fluorescent lamp, when the heat sink cover 20 and the diffusion cover 30 are combined to each other as described above.

[49] The finishing cap 40 is provided with a pair of power supply pins 43 that are electrically connected to the electrical connection part 50.

[50] The heat sink cover 20 and the diffusion cover 30 are each provided with coupling members 25,35 that are interconnected with each other by external pressure.

[51] Particularly, the coupling members 25,35 of the heat sink cover 20 and the diffusion cover 30 have a concavo-convex shape, and therefore a protrusion 35 which is a coupling member formed on the diffusion cover 30 is fitted, connected and fixed into a groove 25 which is a coupling member formed on the heat sink cover 20, by externally applied force.

[52] A waterproof member 70 is further provided on one side of the coupling member of the heat sink cover 20 being in close contact with the diffusion cover 30, and the waterproof member 70 may include a waterproof tape, and the like.

[53] As shown in FIG. 3, a waterproof member 53 is provided on the outer periphery of the protrusion 51 coupled to the finishing cap 40, outside the electrical connection part 50, and the waterproof member 53 may include a waterproof tape, and the like.

[54] An inner end of the heat sink cover 20 is provided with a groove 28 through which the finishing cap 40 can be fitted and connected, and the electrical connection part 50 is provided with a protrusion 55 which is fitted into the groove 28. A waterproof member 57 is provided in the region being in close contact with the heat sink cover 20, on the outer periphery of the protrusion 55. The waterproof member 57 may include a waterproof tape, and the like.

[55] The electrical connection part 50 is provided with a groove 58 through which the diffusion cover 30 can be inserted and connected, and a waterproof member 59 is provided in the region being in close contact with the diffusion cover 30, on the inner surface of the groove 58. The waterproof member 59 may include a waterproof tape, and the like.

[56] An operation voltage of the LED fluorescent lamp using the LEDs 10 as a light source is in a range of 100 to 240V. [57] The operation of the LED fluorescent lamp constructed as above will be described hereinafter.

[58] As shown in FIG. 4, a plurality of LEDs 10 are spaced and arranged at a given interval on the circuit board 15. That is, a plurality of LEDs 10 are regularly spaced such that the light emitted from the LEDs 10 overlaps one another, as shown in FIG. 5.

[59] The circuit board 15 is connected to the heat sink cover 20 while being spaced from the diffusion cover 30, such that overlap points of the light emitted from the LEDs 10 are positioned inside the diffusion cover 30.

[60] The distance (d) between the circuit board 15 and the diffusion cover 30 may be maintained at a given value by controlling a thickness of the circuit board 15.

[61] As described above, the LEDs 10 are provided spaced at a specified distance apart from the diffusion cover 30 such that the overlap points of the light emitted from a plurality of the LEDs 10 are positioned at the shortest distance from the inside wall of the diffusion cover 30.

[62] By such determination of the distance (d) between the LEDs 10 and the diffusion cover 30, a shape or afterimage of the LEDs 10 does not appear on the outer surface of the diffusion cover 30 when the LEDs 10 are turned-on.

[63] Further, multiple heat sink fins 21 are arranged at regular intervals on an outer periphery of the heat sink cover 20, so such a structure results in external dissipation of heat generated by the LEDs 10 when the LEDs 10 are turned-on, whereby elevation of an internal temperature of the LED fluorescent lamp is prevented. Both ends of the heat sink cover 20 are provided with grooves 25 which are coupling members, as shown in FIGS. 2 and 3.

[64] The coupling member protrusions 35 provided on the diffusion cover 30 are fitted into the coupling member grooves 25 by the externally applied force, whereby the heat sink cover 20 and the diffusion cover 30 are combined to form a tube-shaped fluorescent lamp structure. Here, since the diffusion cover 30 is formed with incorporation of a diffusion material, diffusion and emission of LED-emitted light which is as natural as in a conventional fluorescent lamp is achieved, even without installation of an additional diffusion member such as diffusion plate or diffusion film.

[65] Before fitting of the protrusions 35 of the diffusion cover 30 into the grooves 25 of the heat sink cover 20, the waterproof tape 70 is attached to the interface where the heat sink cover 20 and the diffusion cover 30 are in intimate contact, such that internal penetration of moisture including aqueous vapors is prevented.

[66] Under the above combined state, electrical connection parts 50 are first inserted into both ends of a tube-shaped structure formed by combination of the heat sink cover 20 and the diffusion cover 30, and finishing caps 40 are then covered on upper parts of the electrical connection parts 50 such that the electrical connection parts 50 are isolated from the external environment. The finishing cap 40 is provided with power supply pins 43 that are electrically connected to the electrical connection part 50, and receive a supply of a commercial power supply and output an LED-driving power supply to the LED driving section 17 through the electrical connection part 50 (see FIGS. 1 and

2).

[67] Since the waterproof tape 57 is attached to an outer periphery of the protrusion 55 of the electrical connection part 50 being in close contact with the heat sink cover 20 and the waterproof tape 59 is attached to an inner periphery of the groove 58 of the electrical connection part 50 in close contact with the diffusion cover 30, the electrical connection part 50 is more intimately connected to the heat sink cover 20 and the diffusion cover 30, simultaneously resulting in no penetration of airborne moisture into connection apertures of individual components.

[68] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

[69]

Claims

[1] An LED fluorescent lamp comprising: a circuit board on which light-emitting diodes (LED) are arranged and fixed at regular intervals; an LED driving means attached to a lower part of the circuit board and adapted to turn on/off the LEDs in response to signals being input from the outside; a diffusion cover provided on an upper part of the circuit board and diffusing the light emitted from the LEDs; a semi-cylindrical heat sink cover combined to the diffusion cover to form a fluorescent-type tube and having a plurality of heat sink fins formed on the outer periphery thereof; electrical connection means fitted to be connected to both ends of the combined diffusion cover and heat sink cover and outputting an LED-driving power supply to the LED driving means; and a finishing cap connected to an upper part of the electrical connection means and adapted to isolate the electrical connection means from the external environment, wherein the finishing cap is provided with a pair of power supply pins in electrical connection with the electrical connection means.

[2] The lamp according to claim 1, wherein the heat sink cover and the diffusion cover are each provided with coupling members that are interconnected to each other by external pressure.

[3] The lamp according to claim 2, wherein the coupling members formed respectively on the heat sink cover and the diffusion cover have a concavo-convex shape, and a protrusion of the coupling member formed on the diffusion cover is fitted into a groove of the coupling member formed on the heat sink cover by the external pressure, such that the heat sink cover and the diffusion cover are connected and fixed.

[4] The lamp according to claim 2, wherein a waterproof member is further provided on one side of the coupling member of the heat sink cover being in close contact with the diffusion cover.

[5] The lamp according to claim 4, wherein the waterproof member is a waterproof tape.

[6] The lamp according to claim 1, wherein the electrical connection means is provided with a screw-threaded coupling member, and the finishing cap is provided with a hole corresponding to the coupling member, such that a fixing member is screw-connected to the coupling member.

[7] The lamp according to claim 4, wherein a waterproof member is provided on an end connected to the finishing cap, outside the electrical connection means.

[8] The lamp according to claim 4, wherein an inner end of the heat sink cover is provided with a groove through which the electrical connection means can be fitted to be connected, and the electrical connection means is provided with a protrusion which is fitted into the groove.

[9] The lamp according to claim 8, wherein a waterproof member is provided on an outer surface of the protrusion formed on the electrical connection means.

[10] The lamp according to claim 1, wherein the electrical connection means is provided with a groove through which the diffusion cover can be inserted and connected, and a waterproof member is provided on the inner surface of the groove.

[11] The lamp according to claim 1, wherein the spacing between LEDs arranged and fixed on the circuit board is determined such that the light emitted from a given number of LEDs overlaps one another by a light-emitting angle of the LEDs.

[12] The lamp according to claim 1, wherein the diffusion cover is positioned such that the light emitted from the LEDs inside the diffusion cover overlaps one another.

[13] The lamp according to claim 12, wherein the diffusion cover has a semi- cylindrical shape.

[14] The lamp according to claim 1, wherein a fluorescent- type lamp using the LED as a light source has an operation voltage of 100 to 240V.