KR101704032B1 - Light emitting device package and light emitting system - Google Patents

Abstract

A light emitting device package according to an embodiment includes: a body having a cavity; A light emitting element located in the cavity; And a lens positioned on the body, the lens including a first portion having a positive curvature and a second portion having a negative curvature. The first portion corresponds to a central portion of the lens, and the second portion is formed adjacent to the body.

Description

[0001] LIGHT EMITTING DEVICE PACKAGE AND LIGHT EMITTING SYSTEM [0002]

The present invention relates to a light emitting device package.

Light emitting diodes (LEDs) are a type of semiconductor devices that convert electrical energy into light. The light emitting diode has advantages of low power consumption, semi-permanent lifetime, fast response speed, safety, and environmental friendliness compared with conventional light sources such as fluorescent lamps and incandescent lamps.

Accordingly, much research has been conducted to replace an existing light source with a light emitting diode, and there is an increasing tendency to use a light emitting diode as a light source of various lamps, liquid crystal display devices, electric sign boards, to be.

The embodiment provides a light emitting device package capable of reducing chromatic aberration.

A light emitting device package according to an embodiment includes: a body having a cavity; A light emitting element located in the cavity; And a lens positioned on the body, the lens including a first portion having a positive curvature and a second portion having a negative curvature. The first portion corresponds to a central portion of the lens, and the second portion is formed adjacent to the body.

The light emitting device package according to the present embodiment may be formed by forming a second portion corresponding to the peripheral portion of the lens into a concave lens shape having a negative curvature and causing a refractive index difference Chromatic aberration can be reduced.

At this time, it is possible to further reduce the chromatic aberration by providing an auxiliary lens having a refractive index larger than that of the lens in the second portion.

1 is a perspective view of a light emitting device package according to a first embodiment.
2 is a cross-sectional view taken along line II-II in FIG.
3 is a cross-sectional view of a light emitting device package according to the second embodiment.
4 is a perspective view of the auxiliary lens of the light emitting device package according to the second embodiment.
5 is a cross-sectional view of a light emitting device package according to a modification of the second embodiment.
6 is a view illustrating a backlight unit including a light emitting device package according to an embodiment.
7 is a view illustrating an illumination unit including a light emitting device package according to an embodiment.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under / under" Quot; includes all that is formed directly or through another layer. The criteria for top / bottom or bottom / bottom of each layer are described with reference to the drawings.

The thickness or the size of each layer (film), region, pattern or structure in the drawings may be modified for clarity and convenience of explanation, and thus does not entirely reflect the actual size.

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

FIG. 1 is a perspective view of a light emitting device package according to a first embodiment, and FIG. 2 is a sectional view cut along a line II-II in FIG.

1 and 2, a light emitting device package 100 according to the present embodiment includes a body 10 having a cavity 20, a light emitting device 50 disposed in the cavity 20, A molding member 60 surrounding the light emitting device 50 in the cavity 20 and a lens (not shown) disposed on the light emitting device 50. The first electrode 41 and the second electrode 42 are electrically connected to the light emitting device 50 70).

This will be described in more detail as follows.

The body 10 may be formed of a resin such as polyphthalamide (PPA), liquid crystal polymer (LCP), polyamide 9T or PA9T, a metal, a photo sensitive glass, a sapphire ₂ O ₃ ), ceramics, printed circuit boards (PCB), and the like. However, this embodiment is not limited to these materials.

The body 10 may have various shapes depending on the use and design of the light emitting device package 100. For example, the planar shape of the body 10 may have various shapes such as a rectangular shape and a circular shape.

The body (10) is provided with a cavity (20) having an open top. In the drawing, the planar shape of the cavity 20 is shown as a circle, but the present invention is not limited thereto. Accordingly, the cavity 20 may have a planar shape of a polygonal shape including a quadrangle.

The side surface of the cavity (20) may be perpendicular or inclined to the bottom surface of the cavity (20). The angle A between the side surface and the bottom surface of the cavity 20 may be 100 to 170 degrees when the cavity 20 has an inclined side surface. At this time, the angle A may be 120 degrees or more so that the light emitted from the light emitting element 50 can be well reflected.

The body 10 having such a cavity 20 may be formed by laminating a plurality of layers or may be formed through injection molding or the like. It is needless to say that the body 10 can be formed by various other methods.

A first electrode 41 and a second electrode 42 electrically connected to the light emitting device 50 are disposed in the body 10. The first electrode 41 and the second electrode 42 may be formed of a metal plate having a predetermined thickness, and another metal layer may be plated on the surface of the first electrode 41 and the second electrode 42. The first electrode 41 and the second electrode 42 may be formed of a metal having excellent conductivity. Examples of such metals include titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chromium (Cr), tantalum (Ta), platinum (Pt), tin .

A part of the first electrode 41 and the second electrode 42 may be exposed through the cavity 20 and the remaining part may pass through the inside of the body 10 and be exposed to the outside. In this embodiment, the first electrode 41 and the second electrode 42 are formed in contact with the bottom surface of the cavity 20, but the present invention is not limited thereto. Accordingly, the first electrode 41 and the second electrode 42 may be formed in contact with the upper surface of the body 10.

In the cavity 20, the light emitting device 50 is positioned while being electrically connected to the first electrode 41 and the second electrode 42. The light emitting device 50 may be electrically connected to the first electrode 41 and the second electrode 42 by wire bonding through the wire 52.

The light emitting device 50 may be a horizontal chip disposed such that two electrode layers (not shown) are exposed in the upward direction, or a vertical chip having two electrode layers disposed on opposite sides of the light emitting layer. At this time, the horizontal chip may be connected to the first electrode 41 and the second electrode 42 by wires 52, respectively. The vertical chip may be formed in contact with one electrode of the first electrode 41 and the second electrode 42, and may be connected to the other electrode by a wire 52. In FIG. 2, a horizontal chip is used as an example.

However, the embodiment is not limited thereto. That is, the light emitting device 50 and the first and second electrodes 41 and 42 may be electrically connected by die bonding or a flip chip method in addition to wire bonding.

The light emitting device 50 may include a light emitting diode (LED), which may be a colored LED, such as a red LED, a blue LED, a green LED, or an ultraviolet (UV) LED. The embodiments are not limited to the types and the numbers of LEDs. A protective element (for example, a zener diode, a varistor) (not shown) for protecting the LED may be mounted on the body 10.

The molding member 60 is filled in the cavity 20 while sealing the light emitting element 50 therein. The molding member 60 may be made of a light-transmitting material such as silicone or epoxy. The molding member 60 may include a fluorescent material that absorbs light emitted from the light emitting device 50 and emits another wavelength.

A lens 70 for improving light extraction efficiency is placed on the molding member 60. In this embodiment, the lens 70 is formed with a first portion 70a having a positive curvature and a second portion 70b having a negative curvature. That is, the first portion 70a may have a convex lens shape and may be a hemispherical portion, and the second portion 70b may have a concave lens shape at the periphery of the first portion 70a .

The first portion 70a may correspond to a central portion of the lens 70 located at the upper portion of the light emitting device 50 and the second portion 70b may correspond to a peripheral portion of the lens 70 .

A central portion having a small angle? From the central axis C of the lens 70 (or an axis parallel to the light emitted from the light emitting element 50) And the light of the high wavelength band and the light of the low wavelength band can be relatively uniformly emitted. On the other hand, there is a difference in the degree of refraction of the light of the high wavelength band and the light of the low wavelength band in the peripheral portion of the lens 70 where the angle 70 from the central axis C of the lens 70 is large, Section. In consideration of this, in the embodiment, the first portion 70a corresponding to the central portion of the lens 70 is implemented as a convex lens having a positive curvature so that the light is extracted to the peripheral portion of the lens 70 The corresponding second portion 70b is spherical in the shape of a concave lens having a negative curvature, thereby preventing a problem caused by chromatic aberration.

The first portion 70a is a portion where the angle from the central axis C of the lens 70 is less than 0 degrees to less than 60 degrees and the second portion 70b is a portion where the angle 70 from the center axis C of the lens 70 is less than 0 degrees, The angle &thetas; from the center axis C may be 60 DEG to 90 DEG. However, the embodiment is not limited to this angle.

The lens 70 may be formed by molding a resin or the like, or may be attached with a separately manufactured lens. Although the molding member 60 and the lens 70 are separately formed and described in the drawings and the description, the molding member 60 and the lens 70 may be formed together in the same process.

As described above, the light emitting device package 100 according to the present embodiment includes the lens 70 including the first portion 70a having a positive curvature and the second portion 70b having a negative curvature, The efficiency can be improved and the chromatic aberration can be reduced.

Hereinafter, a light emitting device package according to a second embodiment and a modification will be described with reference to FIGS. 3 to 5. FIG. For the sake of clarity, the same or extremely similar components as those of the first embodiment will not be described in detail and only different configurations will be described in detail.

FIG. 3 is a cross-sectional view of a light emitting device package according to a second embodiment, and FIG. 4 is a perspective view of an auxiliary lens of the light emitting device package according to the second embodiment. And FIG. 5 is a cross-sectional view of a light emitting device package according to a modification of the second embodiment.

Referring to FIG. 3, in this embodiment, the auxiliary lens 80 is located in the second portion 70b of the lens 70. In FIG. As shown in Fig. 4, the auxiliary lens 80 may have a ring shape so as to surround the second portion (reference numeral 70b in Fig. 3). However, the present embodiment is not limited to this, and it goes without saying that the auxiliary lens 80 may have various shapes that can form an interface with the second portion 70b of the lens 70. [

The auxiliary lens 80 may be formed by molding the second portion 70b of the lens 70 or attaching the resin after the lens 70 is formed. Alternatively, the auxiliary lens 80 may be separately manufactured and sandwiched in the lens 70. [

The auxiliary lens 80 has a refractive index larger than that of the lens 70. For example, the lens 70 may be made of a relatively crown glass having a refractive index, and the auxiliary lens 80 may be made of a flint glass having a relatively large refractive index. Since aberrations of light of a high wavelength band and light of a low wavelength band can be corrected by combining lenses having different refractive indexes as described above, chromatic aberration can be corrected more efficiently.

For example, the refractive index of the lens 70 may be smaller than 1.6, the refractive index of the auxiliary lens 80 may be larger than 1.6, and the difference between the refractive index of the lens 70 and the refractive index of the auxiliary lens 80 may be 0.1 or more. If the difference between the refractive index of the lens 70 and the refractive index of the auxiliary lens 80 is less than 0.1, the chromatic aberration correction effect can be small. However, the embodiment is not limited to this numerical value.

In this embodiment, the auxiliary lens 80 has a circular cross section, but it is also possible that the auxiliary lens 82 has an elliptical cross section as shown in FIG. 5, which also belongs to the embodiment. It goes without saying that the auxiliary lenses 80 and 82 may have various cross-sectional shapes to form an interface with the second portion 70b of the lens 70. [

The light emitting device package according to the above-described embodiments and modifications may function as an illumination system such as a backlight unit, a pointing device, a lamp, and a streetlight. This will be described with reference to Figs. 6 and 7. Fig.

6 is a view illustrating a backlight unit including a light emitting device package according to an embodiment. However, the backlight unit 1100 of Fig. 6 is an example of the illumination system, and is not limited thereto.

6, the backlight unit 1100 includes a bottom cover 1140, a light guide member 1120 disposed in the bottom cover 1140, a light guide member 1120 disposed on at least one side or bottom surface of the light guide member 1120 A light emitting module 1110 may be included. Further, a reflective sheet 1130 may be disposed below the light guide member 1120.

The bottom cover 1140 may be formed in a box shape having an opened upper surface to accommodate the light guide member 1120, the light emitting module 1100 and the reflective sheet 1130, . However, the present invention is not limited thereto.

The light emitting module 1110 may include a plurality of light emitting device packages 600 mounted on the substrate 700. A plurality of light emitting device packages (600) provide light to the light guide member (1120).

As shown, the light emitting module 1110 may be disposed on at least one of the inner surfaces of the bottom cover 1140, thereby providing light toward at least one side of the light guide member 1120 .

The light emitting module 1110 may be disposed under the light guide member 1120 in the bottom cover 1140 to provide light toward the bottom surface of the light guide member 1120. It can be variously modified according to the design of the backlight unit 1100.

The light guide member 1120 may be disposed in the bottom cover 1140. The light guide member 1120 can guide the light provided from the light emitting module 1110 to a display panel (not shown) by converting the light into a surface light source.

Such a light guide member 1120 may be, for example, a light guide panel (LGP). The light guiding plate may be made of, for example, acrylic resin such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), cyclic olefin copolymer (COC), polycarbonate (PC) , And polyethylene naphthalate resin.

The optical sheet 1150 can be disposed on the upper side of the light guide member 1120.

This optical sheet 1150 may include at least one of, for example, a diffusion sheet, a light condensing sheet, a brightness increasing sheet, and a fluorescent sheet. For example, the optical sheet 1150 may be formed by laminating a diffusion sheet, a light condensing sheet, a brightness increasing sheet, and a fluorescent sheet. In this case, the diffusion sheet 1150 spreads the light emitted from the light emitting module 1110 evenly, and the diffused light can be condensed by the condensing sheet into a display panel (not shown). At this time, the light emitted from the light condensing sheet is randomly polarized light. The brightness increasing sheet can increase the degree of polarization of the light emitted from the light condensing sheet. The light collecting sheet may be, for example, a horizontal or / and a vertical prism sheet. The brightness enhancement sheet may be, for example, a dual brightness enhancement film. Further, the fluorescent sheet may be a translucent plate or film in which the phosphor is spun.

A reflective sheet 1130 may be disposed below the light guide member 1120. The reflective sheet 1130 can reflect light emitted through the lower surface of the light guide member 1120 toward the exit surface of the light guide member 1120. The reflective sheet 1130 may be formed of a resin having high reflectance, for example, PET, PC, poly vinyl chloride, resin, or the like, but is not limited thereto.

7 is a view illustrating an illumination unit including a light emitting device package according to an embodiment. However, the illumination unit 1200 of Fig. 7 is an example of the illumination system and is not limited thereto.

7, the lighting unit 1200 includes a case body 1210, a light emitting module 1230 provided on the case body 1210, a connection terminal 1210 installed on the case body 1210, (1220).

The case body 1210 is preferably formed of a material having a good heat dissipation property, and may be formed of, for example, a metal or a resin.

The light emitting module 1230 may include a substrate 700 and at least one light emitting device package 600 mounted on the substrate 700.

The substrate 700 may be a circuit pattern printed on an insulator. For example, the substrate 700 may be a general printed circuit board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB . ≪ / RTI >

Further, the substrate 700 may be formed of a material that efficiently reflects light, or may be formed of a color whose surface is efficiently reflected, for example, white, silver, or the like.

At least one light emitting device package 600 may be mounted on the substrate 700.

The light emitting device package 600 may include at least one light emitting diode (LED). The light emitting device may include a colored light emitting device that emits red, green, blue, or white colored light, and a UV light emitting device that emits ultraviolet (UV) light.

The light emitting module 1230 may be arranged to have various combinations of light emitting elements to obtain color and brightness. For example, a white light emitting element, a red light emitting element, and a green light emitting element may be disposed in combination in order to secure a high color rendering index (CRI). Further, a fluorescent sheet may be further disposed on the path of the light emitted from the light emitting module 1230, and the fluorescent sheet changes the wavelength of the light emitted from the light emitting module 1230. For example, when the light emitted from the light emitting module 1230 has a blue wavelength band, the fluorescent sheet may include a yellow phosphor, and the light emitted from the light emitting module 1230 may be seen through the fluorescent sheet as white light do.

The connection terminal 1220 may be electrically connected to the light emitting module 1230 to supply power. 7, the connection terminal 1220 is connected to the external power source by being inserted in a socket manner, but the present invention is not limited thereto. For example, the connection terminal 1220 may be formed in a pin shape and inserted into an external power source or may be connected to an external power source by wiring.

In the above-described illumination system, at least one of a light guide member, a diffusion sheet, a light condensing sheet, a brightness increasing sheet, and a fluorescent sheet is disposed on the path of light emitted from the light emitting module to obtain a desired optical effect.

As described above, the illumination system can have excellent optical characteristics by including the light emitting device package with reduced chromatic aberration.

The features, structures, effects and the like described in the foregoing embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. Further, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified in other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the present invention. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments may be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

Claims (10)

A body having a cavity;
A light emitting element located in the cavity; And
And a lens positioned on the body and including a first portion having a positive curvature and a second portion having a negative curvature,
Wherein the first portion corresponds to a central portion of the lens and the second portion is disposed outside the first portion and is disposed adjacent to the body,
And an auxiliary lens located in a second portion of the lens. The method according to claim 1,
When the angle of the lens from the central axis is?
Wherein the first portion is a portion where the angle [theta] is less than 0 [deg.] And less than 60 [deg.], And the second portion is a portion having the angle [theta] of 60 [deg.] To 90 [deg.]. The method according to claim 1,
Wherein the first portion has a convex lens shape and the second portion has a concave lens shape. The method according to claim 1,
Wherein the lens is formed of crown glass, and the auxiliary lens is formed of flint glass. The method according to claim 1,
Wherein a refractive index of the auxiliary lens is larger than a refractive index of the lens. 6. The method of claim 5,
Wherein the refractive index of the lens is smaller than 1.6 and the refractive index of the auxiliary lens is larger than 1.6. 6. The method of claim 5,
Wherein a difference between a refractive index of the lens and a refractive index of the auxiliary lens is 0.1 or more. The method according to claim 1,
Wherein the auxiliary lens surrounds the second portion. The method according to claim 1,
Wherein the auxiliary lens has a circular or elliptical cross section. 10. An illumination system comprising a light emitting device package according to any one of claims 1 to 9.

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