KR102276955B1 - surface emitting LED lighting apparatus - Google Patents

Abstract

The present invention relates to a planar emitting LED lighting apparatus to stably mount a light diffusing lens on a circuit board without deflection or distortion. According to the present invention, the planar emitting LED lighting apparatus comprises: a main frame including a horizontal base plate and side plates; a circuit board mounted on the horizontal base plate; a plurality of LEDs arrayed on the circuit board; a light diffusion cover including a light diffusion plate and a cover frame installed around the light diffusion plate and coupled to block an open portion of the main frame; a plurality of light diffusion lenses mounted on the circuit board to cover each of the LEDs and including a bottom surface having a parabolic light incident surface axially symmetric with respect to an optical axis and a light emitting surface axially symmetric with respect to the optical axis; and a reflective sheet having holes formed therein to pass the light diffusion lenses therethrough and stacked on the circuit board. The light emitting surface includes a main section in which the distance of the light coming from the LED and reaching the light emitting surface increases gradually as the distance from the optical axis increases and a concave portion axially symmetric with the optical axis and recessed in a direction closer to the LED is disposed in the main section.

Description

Surface emitting LED lighting apparatus

The present invention relates to a surface light emitting LED lighting device, and more particularly, to a direct-type LED lighting device having improved luminance uniformity and light efficiency and having a slim structure.

LED (Light Emitting Diode) has good luminous efficiency and is used as a light source for various purposes. However, since such an LED is a point light source with very high luminance, there are many limitations as a general indoor lighting device for illuminating an indoor space in which people are present. Accordingly, including the light guide plate and a structure in which a plurality of LEDs are arranged along the edges of the light guide plate, light emitted from the LEDs enters through the edge of the light guide plate and is emitted through the upper or lower surface of the light guide plate. Edge type surface light emitting A lighting device was developed. Such an edge-type surface light emitting lighting device is configured to widen a light emitting area by a light guide plate and a prism sheet.

However, the edge-type surface light emitting lighting device as described above has a problem in that the light efficiency is low due to a large loss of light in the light guide plate, and the light that enters the light guide plate and cannot be emitted is converted into thermal energy, so that the light guide plate is likely to be deformed by heat. In addition, the expansion and contraction rate of the light guide plate is not constant, so when it receives heat for a long time, the light invades the outline and malfunctions.

On the other hand, although many studies have been made on a direct surface light emitting LED lighting device in which the LEDs are disposed directly under the diffusion plate, it is difficult to slim the device due to the required distance between the light diffusion plate and the LEDs, and it is still difficult to increase the brightness uniformity There were limits to

Republic of Korea Patent Registration No. 10-1933571 (Registration Date December 21, 2018)

The present invention has been devised in view of the above points, and an object of the present invention is to provide a direct surface light emitting LED lighting device having a slim structure while excellent in luminance uniformity and light efficiency.

Objects of the present invention are not limited to those described above, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

Surface-emitting LED lighting device according to the present invention for achieving the object as described above, a main frame including a horizontal base plate and a side plate; a circuit board mounted on the horizontal base plate; a plurality of LEDs arrayed on the circuit board; a light diffusion cover including a light diffusion plate and a cover frame installed around the light diffusion plate, the light diffusion cover coupled to block an open portion of the main frame; a plurality of light diffusion lenses mounted on the circuit board to cover each of the LEDs and including a bottom surface having a parabolic light incident surface axially symmetric with respect to the optical axis and a light emitting surface axially symmetric with respect to the optical axis; and a reflective sheet in which holes passing through the light diffusion lenses are formed and stacked on the circuit board, wherein the light exit surface increases as the distance of light coming out of the LED and reaching the light exit surface increases from the optical axis It includes a gradually increasing main section, and in the main section, there is a concave portion axially symmetric with the optical axis and recessed in a direction closer to the LED.

The surface light emitting LED lighting apparatus further includes a peripheral light reflection unit disposed inside the main frame or inside the light diffusion cover to surround the LEDs and the light diffusion lenses.

Each of the light diffusion lenses includes a scattering pattern portion formed on the bottom portion to surround the outer periphery of the light incident surface, and the bottom portion to protrude further below the scattering pattern portion and surround the periphery of the scattering pattern portion. It further includes a barrier wall formed on the outside.

Each of the light-diffusion lenses further includes a plurality of lens legs extending downward from the region of the scattering pattern portion and bonded to the circuit board together with the blocking wall.

Heat dissipation holes are formed in the blocking wall at regular intervals, and a straight line connecting each of the heat dissipation holes and the center of the light incident surface passes through each of the lens legs.

The surface light emitting LED lighting device according to the present invention as described above can solve the problems of the existing edge type surface light emitting LED lighting device such as heat shrinkage of the light guide plate by omitting the light guide plate.

In addition, the surface light emitting LED lighting device according to the present invention has the advantage of being able to provide surface light having uniform luminance, even though the light guide plate is omitted.

In addition, the surface light emitting LED lighting device according to the present invention has the advantage of being able to scatter the light that does not pass through the light exit surface and reach the bottom surface of the light diffusion lens to be uniformly re-emitted.

In addition, in the surface light emitting LED lighting device according to the present invention, since the lens legs and the blocking wall located outside the lens legs are erected in contact with the circuit board, the light diffusion lens can be stably mounted on the circuit board without sagging or twisting to one side.

In addition, although the LED is closed by a barrier wall, there is an advantage in that the heat dissipation characteristics are good due to the structure that emits heat through the heat dissipation hole.

1 is an exploded perspective view showing a surface light emitting LED lighting device according to an embodiment of the present invention.
2 is an enlarged plan view of a part of the surface light emitting LED lighting device according to an embodiment of the present invention with the cover removed.
FIG. 3 is a cross-sectional view taken along line AA of FIG. 2 .
FIG. 4 is a bottom view of the light diffusing lens shown in FIG. 3 .
5 is a perspective view illustrating an upper surface of the light diffusing lens shown in FIGS. 3 and 4 .
6 is a perspective view illustrating a bottom portion of the light diffusing lens shown in FIGS. 3 and 4 .

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In describing the present invention, the size or shape of the components shown in the drawings may be exaggerated or simplified for clarity and convenience of explanation.

In addition, terms specifically defined in consideration of the configuration and operation of the present invention may vary depending on the intention or custom of the user or operator. These terms should be interpreted as meanings and concepts consistent with the technical spirit of the present invention based on the contents throughout this specification.

In order to clearly explain the present invention, the description of parts not related to the technical idea of the present invention is omitted, and the same reference numerals are given to the same or similar elements throughout the specification.

In addition, in various embodiments, components having the same configuration will be described using the same reference numerals only in the representative embodiment, and only configurations different from the representative embodiment will be described in other embodiments.

Throughout the specification, when a part is "connected" to another part, it includes not only the case where it is "directly connected" but also the case where it is "indirectly connected" with another member interposed therebetween. In addition, when a part "includes" a certain component, this may mean further including other components rather than excluding other components unless otherwise stated.

1 to 6, the surface light emitting LED lighting device according to an embodiment of the present invention includes a main frame 10 including a horizontal base plate 12 and a side plate 14, and the horizontal base plate ( 12) on the circuit board 20 mounted on the circuit board 20, a plurality of LEDs 40 arrayed on the circuit board 20, and on the circuit board 20 to cover each of the LEDs 40 Light including an attached light diffusion lens 60 , a light diffusion plate 92 , and a cover frame 94 installed around the light diffusion plate 92 , and coupled to block the opening of the main frame 10 . and a diffusion cover 90 .

In addition, in the surface light emitting LED lighting device according to this embodiment, holes 82 through which the light diffusion lenses 60 pass are formed and a reflective sheet 80 stacked on the circuit board 20, and the LED It further includes a peripheral light reflection unit 70 installed inside the main frame 10 or inside the light diffusion cover 90 so as to surround the 40 and the light diffusion lenses 60 as a whole. The peripheral light reflection unit 70 includes a reflective surface that reflects the light emitted from the LEDs 40 and the light diffusion lens 60, and the reflective surface of the peripheral light reflection unit 70 is the main frame ( 10) facing parallel to the side wall 14 .

The circuit board 20 includes a plurality of transverse extension bars 22 having a predetermined width and parallel to each other and one longitudinal extension bar 24 connecting one end of the plurality of transverse extension bars 22 . . Both the transverse extension bars 22 and the longitudinal extension bars 24 have a bar shape having a predetermined width. The above-described LEDs 40 are composed of a plurality of LED groups, and each LED group is arranged in a line along the corresponding horizontal extension bar 22 . In addition, between the LEDs 40 of the neighboring LED groups may be connected in series or in parallel by wiring.

A printed circuit board (PCB) having a rectangular or square shape is used in the existing LED lighting device, and the conventional PCB is prone to sagging or torsion due to a large area. As a result, the LEDs mounted on the PCB There was a high risk of height differences between the two. When the height difference becomes large, a difference occurs between the distance between the LED and the light-diffusing lens, which inhibits the generation of surface light of uniform luminance.

On the other hand, according to the present embodiment, since a plurality of transverse extension bars 22 having a narrow width and a longitudinal extension bar 24 having a similarly narrow width constitute one circuit board 20, compared to the conventional one, sagging However, the risk of warpage is small. The circuit board 20 is preferably a metal PCB or MCPCB having good heat generating performance. In addition, the upper surface of the circuit board 20 is preferably a reflective surface.

Meanwhile, the horizontal base plate 12 of the main frame 10 includes a plurality of heat dissipation slot holes 121 formed in a direction crossing the transverse extension bars 22 . The heat dissipation slot holes 121 are formed to pass through a region directly under the LED 40 , and greatly contribute to dissipating heat generated in the LED 40 to the outside.

In addition, the LEDs 40 are arrayed in a matrix arrangement on the circuit board 20 , and the light diffusion lens 60 is arrayed in a matrix arrangement on the circuit board 20 to cover the LEDs 40 . do.

The LEDs 40 may include a blue LED chip and one or more wavelength conversion materials that convert the wavelength of light emitted by the blue LED chip. A combination of a green phosphor and a red phosphor capable of producing white light by converting blue light to a wavelength or a yellow phosphor may be advantageously used as a wavelength conversion material. The LEDs 40 are either LED packages having a structure in which an LED chip is mounted in a package housing in which lead terminals are installed on electrodes (not shown) of the circuit board 20, or electrode pads provided in the LED chip are directly circuit boards. It may be a flip-chip type LED chip or a CSP (Chip Scale Package) LED bonded to the electrodes formed in 20 .

The light-diffusing lens 60 greatly reduces the distance between the LED 40 and the light-diffusing plate 94 by spreading the light widely without a light guide plate, as will be described in detail below, while surrounding the LED 40 almost entirely. It is possible to minimize the light leaking without passing through the light diffusion lens 60, and furthermore, despite the structure that almost completely covers the LED 40, the heat generated during the operation of the LED 40 can be well discharged to the outside. configured to be able to

Now, the structure and characteristics of the light-diffusion lens 60 will be described in more detail.

As shown, the light diffusing lens 60 includes a bottom portion having a concave light incident surface 61 formed in the center, and an upper surface portion having a light exit surface 66 formed therein.

The light incident surface 61 is formed as a concave in the form of a parabola axially symmetrical with respect to the optical axis C of the LED 40 . In more detail with respect to the light incident surface 61 made of a parabolic concave portion, a central point P1, the light incident surface 61, is an imaginary point where the optical axis C and the upper surface of the LED 40 intersect. If the angle that a straight line connecting an arbitrary point on the image and the center point P1 reaches the optical axis is a1, and the distance between a point on the light incident surface 61 and the center point P1 is defined as r1, a1 is approximately at 0 degrees. r1 is gradually decreased until 70 degrees is reached. In this embodiment, even in the section where a1 exceeds 70 degrees and reaches 90 degrees, r1 is gradually reduced, but only the light incident surface 61 has a parabolic shape or a bell shape only up to about 70 degrees. It has sufficient light-diffusion effect.

The light exit surface 66 has a concave portion 662 that is recessed in a direction closer to the LED 40 in a section of about 20 to 30 degrees from the center of the point where it meets the optical axis C. The point at which the optical axis C and the upper surface of the LED 40 intersect is the central point P1, and the straight line connecting a point P3 on the light exit surface 66 and the central point P1 is the angle to the optical axis. If a2, a distance between an arbitrary point P3 on the light exit surface 66 and the central point C is defined as r2, r2 gradually increases until a2 reaches from 0 degrees to approximately 70 degrees. Due to the shape of the light-diffusion lens 60 , the light emitted from the LED 40 and incident on the light-incident surface 61 is primarily bent outward (ie, in a direction wider with respect to the optical axis), and the light The light primarily bent at the incident surface 61 is further bent outward by the shape of the light exit surface 66 described above.

In other words, the light exit surface 66 is a main section that gradually increases as the distance of the light coming out of the LED 40 and reaching the light exit surface 66 is farther from the optical axis, that is, the optical axis (C). It includes a section up to about 70 degrees from, and in the main section, there is a concave portion 662 that is axially symmetric with the optical axis C and recessed in a direction closer to the LED 40 . In addition, the light exit surface 66 gradually and naturally spreads the light outward in the main section and emits it to the outside.

In addition, the bottom portion of the light diffusion lens 60 further includes an extended portion 62 that is extended to accommodate the LED 40 of a relatively large size in the lower periphery of the light incident surface 61 .

On the other hand, some of the light coming out of the LED 40 and passing through the light incident surface 61 is not emitted from the light exit surface 66 to the outside due to Fresnel reflection, but is reflected downward to the light diffusion lens 60 It can reach the peripheral outer region of the light incident surface 61 among the bottom of the . Such light is reflected by the reflective surface of the circuit board 20 and is directed directly upward, which may cause luminance non-uniformity.

To prevent this, the light diffusion lens 60 according to the present embodiment further includes a scattering pattern portion 63 formed in a ring shape on the bottom surface to surround the outer periphery of the light incident surface 61 . Depending on the shape of the light incident surface 61 and the light exit surface 66, the amount and direction of the light directed to the scattering pattern portion 63 may vary. Correspondingly, the region of the scattering pattern portion 63 design the area. The scattering pattern portion 63 may be formed in a continuous pyramid-shaped irregularities.

In addition, the light diffusion lens 60, the scattering pattern portion 63 on the outside of the scattering pattern portion 63 so as to block or suppress leakage to the outside between its bottom portion and the circuit board 20 . It further includes a ring-shaped barrier wall 64 protruding further downward. A bonding material may be interposed between the bottom surface of the blocking wall 64 and the circuit board 20 . When the bonding material is applied to the entire bottom surface of the blocking wall 64, it is possible to more reliably prevent light from leaking to the side.

Meanwhile, a plurality of lens legs 65 are formed on the bottom surface of the light diffusion lens 60 so that the light diffusion lens 60 can be erected on the circuit board 20 without being inclined. In this embodiment, the lens legs 65 are formed at intervals of 120 degrees in the area of the scattering pattern part 63 . At this time, each of the lens legs 65 has a cylindrical cross section. Also, the lens legs 65 extend downward to the same length as the blocking wall 64 . Accordingly, when the lens legs 65 are bonded to the upper surface of the circuit board 20 , the blocking wall 64 is bonded to and in contact with the circuit board 20 . A bonding material is interposed between the blocking wall 64 and the circuit board 20 and between the lens bridge 65 and the circuit board 20 .

Meanwhile, heat dissipation holes 642 are formed in the blocking wall 64 at regular intervals. In this embodiment, the heat dissipation holes 642 are formed at regular intervals on the bottom surface of the blocking wall 64 to form an air passage connecting the periphery of the LED 40 trapped by the blocking wall 64 to the outside. do. At this time, the position of the lens legs 65 and the heat dissipation hole ( 642) are located. The lens legs 65 serve to prevent light from leaking through the heat dissipation hole 642 , but help heat to be well radiated to the outside through the heat dissipation hole 642 .

In addition, the light-diffusion lens 60 includes a side portion connecting the upper surface portion and the bottom surface portion, and a plurality of protrusions 631 protruding in the radial direction at regular angular intervals are formed on the side portion. The protrusion 631 may serve as a reference for attaching the light diffusing lens 60 to the circuit board 20 when the light diffusing lens 60 is attached to the circuit board 20 .

While the present invention has been shown and described in connection with preferred embodiments for illustrating the principles of the present invention, the present invention is not limited to the construction and operation as so shown and described, and is not intended to be limited by the appended claims. It will be understood by those skilled in the art that many changes and modifications can be made to the present invention without departing from the spirit and scope of the present invention.

10..............................Main frame
20 ...............................Circuit board
40 ............................... LED
60 ............................... Light diffusing lens
80 ...............................Reflective sheet

Claims (5)

a main frame 10 including a horizontal base plate 12 and a side plate 14;
It is mounted on the horizontal base plate 12, having a predetermined width and having a plurality of horizontal extension bars 22 parallel to each other and a longitudinal extension bar 24 connecting one end of the horizontal extension bars 22 circuit board 20;
a plurality of LEDs 40 arrayed on the horizontal extension bars 22 of the circuit board 20;
a light diffusion cover (90) including a light diffusion plate (92) and a cover frame (94) installed around the light diffusion plate (92) and coupled to block an open portion of the main frame (10);
It is mounted on the circuit board 20 so as to cover each of the LEDs 40, and a bottom part having a parabolic light incident surface 61 axially symmetric with respect to the optical axis C and an axis with respect to the optical axis C. a plurality of light diffusing lenses 60 including a symmetric light exit surface 66; and
Holes 82 through which the light-diffusion lenses 60 pass are formed and include a reflective sheet 80 stacked on the circuit board 20,
A plurality of heat dissipation slot holes 121 in the horizontal base plate 12 of the main frame 10 in a direction intersecting with the horizontal extension bars 22 so as to dissipate the heat generated by the LEDs 40 to the outside. are formed,
The light exit surface 66 includes a main section in which the distance of light coming from the LED 40 and reaching the light exit surface 66 is gradually increased as the distance from the optical axis C increases, the main section A surface light emitting LED lighting device, characterized in that there is a concave portion 662 that is axially symmetric with the optical axis (C) and recessed in a direction closer to the LED (40).
According to claim 1,
To surround the periphery of the LEDs 40 and the light-diffusion lenses 60, a peripheral light-reflecting part 70 disposed inside the main frame 10 or the light-diffusion cover 90 is further added. Surface light emitting LED lighting device, characterized in that it comprises.
According to claim 1,
Each of the light-diffusion lenses 60,
a scattering pattern portion 63 formed on the bottom surface to surround the outer periphery of the light incident surface 61;
It further comprises a blocking wall 64 which protrudes further downward than the scattering pattern part 63 and is formed on the outside of the bottom surface to surround the periphery of the scattering pattern part 63 to block light leakage. A surface emitting LED lighting device.
4. The method of claim 3,
Each of the light-diffusion lenses 60 further includes a plurality of lens legs 65 that extend downward from the region of the scattering pattern part 63 and are bonded to the circuit board 20 together with the blocking wall 64 . Surface light emitting LED lighting device, characterized in that it comprises.
5. The method of claim 4,
Heat dissipation holes 642 are formed in the blocking wall 64 at regular intervals, and a straight line connecting each of the heat dissipation holes 642 and the center of the light incident surface 61 is formed on each of the lens legs 65 . Surface-emitting LED lighting device, characterized in that passing.

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