KR102145920B1 - Light emitting device package - Google Patents

Abstract

An embodiment includes a package body; A first lead frame to a third lead frame exposed from a part of the package body; A light emitting device disposed on the first lead frame; And a dummy pad disposed on the package body, wherein the light emitting device is wire-bonded to the second lead frame and wire-bonded to the third lead frame via the dummy pad.

Description

Light emitting device package{LIGHT EMITTING DEVICE PACKAGE}

The embodiment relates to a light emitting device package, and more particularly, to improving the electrical characteristics of the light emitting device package.

Group 3-5 compound semiconductors such as GaN and AlGaN are widely used in optoelectronics and electronic devices due to their many advantages, such as having a wide and easily adjustable band gap energy.

In particular, light emitting devices such as light emitting diodes and laser diodes using a group 3-5 or group 2-6 compound semiconductor material of semiconductors are developed in thin film growth technology and device materials, such as red, green, blue and ultraviolet rays. Various colors can be implemented, and efficient white light can be realized by using fluorescent materials or by combining colors. Low power consumption, semi-permanent life, quick response speed, safety, and environment compared to conventional light sources such as fluorescent lamps and incandescent lamps. It has the advantage of affinity.

Therefore, a light-emitting diode backlight that replaces the cold cathode fluorescent lamp (CCFL) constituting the transmission module of the optical communication means, the backlight of the LCD (Liquid Crystal Display) display device, and white light that can replace fluorescent or incandescent bulb Applications are expanding to diode lighting devices, automobile headlights and traffic lights.

1A and 1B are perspective and plan views of a conventional light emitting device. 1A is a perspective view, but for convenience of understanding, first to third lead frames 121 to 123 are shown outside the package body 110.

In the light emitting device package 100, a cavity is formed in the package body 110, and two light emitting devices 140a and 140b are spaced apart from each other by a predetermined distance d ₁ on the bottom surface of the cavity.

A first lead frame 121, a second lead frame 122, and a third lead frame 123 are disposed under the package body 110, and the first to third lead frames 121 to 123 Can be exposed at the bottom of the cavity.

The exposed first lead frame 121 and the second lead frame 122 are formed by the first insulating layer 131, and the first lead frame 121 and the third lead frame 123 are each a second insulating layer. Electrically insulated by 132.

In addition, each of the light emitting devices 140a and 140b may be bonded to the exposed second lead frame 122 and the third lead frame 123 with a wire (not shown), and the two light emitting devices 140a and 140b Also, they may be electrically connected to each other by bonding them with wires.

The length (d ₂ ) in the horizontal direction of the package body 110 may be 6.0 mm, and the separation distance (d ₃ ) between the first insulating layer 131 and the second insulating layer 132 may be 3.18 mm, The length (d ₄ ) in the vertical direction of the package body 110 may be 1.4 mm, and the separation distance (d ₁ ) between the two light emitting devices 140a and 140b is the first insulating layer 131 and the second insulating layer It may be smaller than the separation distance (d ₃ ) of (132).

However, the conventional light emitting device package has the following problems.

The distance between the two light-emitting elements 140a and 140b is relatively larger than the distance between the respective light-emitting elements 140a and 140b, the first insulating layer 131 and the second insulating layer 132, and thus, two light emitting devices The length of the wire electrically connecting the elements 140a and 140b is relatively long.

Therefore, as the length of the wire increases, the stress applied to the wire increases, and the wire may break according to the increase in the stress. In addition, increasing the diameter of the wire increases the cost and increases the amount of light reflected by the wire, so that the light efficiency of the light emitting device package may decrease.

As shown in FIG. 2A, as the length of the wire increases, the stress applied to the wire increases.

2B and 2C are views showing the stress along the length of the wire in the horizontal direction. It can be seen that the stress applied to the wire increases significantly when the wire length is 1,600 micrometers than when the length is 800 micrometers.

The embodiment aims to improve the durability of a wire in a light emitting device package.

An embodiment includes a package body; A first lead frame to a third lead frame exposed from a part of the package body; A light emitting device disposed on the first lead frame; And a dummy pad disposed on the package body, wherein the light emitting device is wire-bonded to the second lead frame and wire-bonded to the third lead frame via the dummy pad.

A distance between the light emitting device and the third lead frame may be greater than a distance between the light emitting device and the second lead frame.

A cavity is formed in the package body, the cavity includes a bottom surface and a side wall, and the light emitting device may be disposed on the bottom surface of the cavity.

The second lead frame and the third lead frame may be exposed to face each other in an edge area of the bottom surface of the cavity.

An insulating layer may be disposed in a region between the first lead frame and the second lead frame, and in a region between the first lead frame and the third lead frame.

The dummy pad may have a first conductive layer disposed on its surface.

The dummy pad may further include an insulating layer disposed under the first conductive layer.

The dummy pad may have a length in a first direction smaller than a length in a second direction, and the second direction may be a direction connecting the light emitting device and the third lead frame.

In the light emitting device package according to the embodiment, a dummy pad is disposed, so that even if the length of the wire connecting the light emitting device and the lead frame increases, the wire passes through the dummy pad, so that stress on the wire may be reduced. Accordingly, since the wire is not broken in the light emitting device package, durability is excellent, and the diameter of the wire does not increase, so that the light output of the light emitting device package may not be lowered.

1A and 1B are perspective and plan views of a conventional light emitting device,
2A to 2C are diagrams showing the stress according to the length of the wire in the horizontal direction,
3A and 3B are perspective and plan views of a light emitting device according to an embodiment,
4 is a cross-sectional view of a dummy pad,
5 is a plan view of the dummy pad,
6 is a view showing an embodiment of an image display device including a light emitting device,
7 is a view showing an embodiment of a lighting device including a light emitting device.

Hereinafter, embodiments of the present invention capable of realizing the above object will be described with reference to the accompanying drawings.

In the description of the embodiment according to the present invention, in the case where it is described as being formed in "on or under" of each element, the upper (upper) or lower (lower) (on or under) includes both elements in direct contact with each other or in which one or more other elements are indirectly formed between the two elements. In addition, when expressed as "on or under", it may include not only an upward direction but also a downward direction based on one element.

3A and 3B are perspective and plan views of a light emitting device according to an embodiment.

The light emitting device package 200 has a cavity formed in the package body 210, the cavity includes a bottom surface and a side wall, and the light emitting device 240 is disposed on the bottom surface of the cavity. One light-emitting device 240 is shown in the present embodiment, but is not limited thereto, and a dummy pad 260 is disposed on the bottom surface of the cavity in addition to the light-emitting device 240.

The package body 210 may be made of an insulating material, and when made of a conductive material, an insulating layer may be disposed on the surface by a method such as coating.

A first lead frame 221, a second lead frame 222, and a third lead frame 223 are disposed under the package body 210, and the first to third lead frames 221 to 223 A portion of the bottom surface of the silver cavity may be exposed. The first to third lead frames 221 to 223 may be made of a conductive material such as copper (Cu).

The first lead frame 221 may be exposed in the central area of the bottom surface of the cavity, and the second lead frame 222 and the third lead frame 223 may be exposed facing each other in the edge area.

An insulating layer may be disposed in an area between the first lead frame 221 and the second lead frame 222 and in the area between the first lead frame 221 and the second lead frame 223, in detail The first lead frame 221 and the second lead frame 222 are formed by the first insulating layer 231, and the first lead frame 221 and the third lead frame 223 are each formed by a second insulating layer ( 232) can be electrically insulated.

The light emitting device 240 includes an undoped semiconductor layer (un-GaN), a first conductivity type semiconductor layer (n-GaN), an active layer (MQW), and a second conductivity type semiconductor layer (p) on a substrate made of sapphire or the like. A light emitting structure including -GaN) may be formed, and a first electrode and a second electrode may be disposed on the first conductive type semiconductor layer and the second conductive type semiconductor layer, respectively. In addition to the horizontal light emitting device having the above-described structure, the light emitting device 240 may include a vertical light emitting device or a flip chip type light emitting device.

The dummy pad 260 is disposed between the light emitting device 240 and the second insulating layer 232, but may be disposed in the'C' region between the light emitting device 240 and the first insulating layer 231 Also, depending on the size of the light emitting device package 200, they may be disposed on both sides.

In this embodiment, the light emitting device 240 is disposed at the same distance as the second lead frame 222 and the third lead frame 223, respectively, but the light emitting device 240 is farther away from the third lead frame 223. At this time, the dummy pad 260 may be disposed between the light emitting device 240 and the third lead frame 223.

The light emitting device 240 may be bonded to the exposed second lead frame 222 and the third lead frame 223 with a wire (not shown). In the illustrated embodiment, the light emitting device 240 is a second lead frame It is connected to 222 by a wire, and may be connected to the third lead frame 223 by a wire through a dummy pad 260.

That is, the light emitting device 240 and the dummy pad 240 may be connected by wire, and the dummy pad 260 may be electrically connected to the exposed third lead frame 223 by wire.

In FIG. 3B,'a'and'b' are regions to which wires are bonded in the second lead frame 222 and the third lead frame 223, respectively. The distance d ₅ between the center of the bonding area'a' on the second lead frame 222 and the center of the area'C' on the first lead frame 221 is'a bonding area on the third lead frame 223' It may be equal to the distance d ₅ between the center of b′ and the center of the dummy pad 260, but may be 0.87 millimeters in this embodiment.

The distance (d ₆ ) between the center area on the light emitting device 240 and the center on the dummy pad 260 may be 0.82 mm, and the separation distance (d ₇ ) between the light emitting device 240 and the dummy pad 260 is It can be 0.54 millimeters. In addition, a separation distance d ₈ between the dummy pad 260 and the second insulating layer 232 may be 0.54 mm, and a separation distance d ₉ between the light emitting element 240 and the first insulating layer 231. ) May be 1.42 millimeters.

4 is a cross-sectional view of a dummy pad, and FIG. 5 is a plan view of the dummy pad.

In the dummy pad 260, the insulating layer 263 may be disposed on the substrate 261, the first conductive layer 265 may be disposed on the insulating layer 263, and a bonding layer may be disposed under the substrate 261. (267) can be placed.

The substrate 261 may be a silicon substrate, etc., the insulating layer 263 may be silicon oxide (SiO ₂ ), the first conductive layer 265 may be a region to which the above-described wire is bonded, and a bonding layer Reference numeral 267 is a region where the substrate 261 constituting the dummy pad 260 is bonded to the above-described first lead frame or the like.

Both the first conductive layer 265 and the bonding layer 267 may be made of metal, and in detail, may have a multilayer structure of Ti/Ni/Ag, where Ti, Ni, and Ag are respectively 1,000 angstroms and 4,000 ohms. It can have a thickness of strong and 10,000 angstroms.

In FIG. 5, when the horizontal direction is referred to as the first direction and the vertical direction is referred to as the second direction, the second direction may be a direction connecting the light emitting device and the third lead frame, that is, a horizontal direction in FIGS. 3A and 3B. The dummy pad 260 may have a length in the first direction smaller than a length in the second direction.

4 and 5, the cross-sectional area of the insulating layer 263 may be narrower than that of the substrate 261, and the cross-sectional area of the first conductive layer 265 may be narrower than the cross-sectional area of the insulating layer 263.

The length of the substrate 261 in the first direction in the horizontal direction (W ₃₁ ) may be smaller than the length in the second direction in the vertical direction (W ₃₂ ), and the length of the insulating layer 263 in the first direction (W ₂₁ ) May be smaller than the length W ₂₂ in the second direction, and the length W _{11 in} the first direction of the first conductive layer 265 may be smaller than the length W ₁₂ in the second direction.

More specifically, the length (W ₃₁ ) in the first direction in the horizontal direction of the substrate 261 may be 270 micrometers, the length in the second direction in the vertical direction (W ₃₂ ) may be 520 micrometers, and the insulating layer The length (W ₂₁ ) in the first direction of 263 may be 240 micrometers, the length in the second direction (W ₂₂ ) may be 490 micrometers, and the first conductive layer 265 may be in the first direction ( W ₁₁ ) may be 230 micrometers and the length in the second direction (W ₁₂ ) may be 480 micrometers.

In the light emitting device package according to the above-described embodiments, the dummy pad is disposed, so that even if the length of the wire connecting the light emitting device and the lead frame increases, the wire passes through the dummy pad, thereby reducing stress on the wire. have. Therefore, since the wire is not broken in the light emitting device package, the durability is excellent, and the diameter of the wire is not increased, so that the light output is excellent. In particular, the amount of light of one light emitting device is increased, so that the light emitting device package of the size of FIG. When only one light emitting device is disposed, a dummy pad may be further required to reduce stress applied to the wire.

Hereinafter, an image display device and a lighting device will be described as an embodiment of a lighting system in which the above-described light emitting device package is disposed.

6 is a diagram showing an embodiment of an image display device in which a light emitting device is disposed.

As shown, the image display device 500 according to the present embodiment includes a light source module, a reflector 520 on the bottom cover 510, and light emitted from the light source module disposed in front of the reflector 520. The first prism sheet 550 and the second prism sheet 560 and the second prism sheet 560 are disposed in front of the light guide plate 540 to guide the image display device in front of the light guide plate 540. It includes a panel 570 disposed in front and a color filter 580 disposed in the entirety of the panel 570.

The light source module includes a light emitting device package 535 on the circuit board 530. Here, the circuit board 530 may be a PCB or the like, and the light emitting device package 535 is as described above.

The bottom cover 510 may accommodate components in the image display device 500. The reflector 520 may be provided as a separate component as shown in this drawing, or may be provided in a form coated with a material having high reflectivity on the rear surface of the light guide plate 540 or the front surface of the bottom cover 510.

The reflector 520 may use a material that has high reflectivity and can be used in an ultra-thin type, and may use PolyEthylene Terephtalate (PET).

The light guide plate 540 scatters light emitted from the light emitting device package module so that the light is uniformly distributed over the entire screen area of the liquid crystal display. Accordingly, the light guide plate 530 is made of a material having a good refractive index and transmittance, and may be formed of polymethylmethacrylate (PMMA), polycarbonate (PC), or polyethylene (PolyEthylene; PE). In addition, if the light guide plate 540 is omitted, an air guide type display device may be implemented.

The first prism sheet 550 is formed of a light-transmitting and elastic polymer material on one surface of the support film, and the polymer may have a prism layer in which a plurality of three-dimensional structures are repeatedly formed. Here, the plurality of patterns may be repeatedly provided in a stripe type with floors and valleys as shown.

In the second prism sheet 560, a direction of a floor and a valley on one side of the support film may be perpendicular to a direction of a floor and a valley on one side of the support film in the first prism sheet 550. This is to evenly distribute the light transmitted from the light source module and the reflective sheet in all directions of the panel 570.

In this embodiment, the first prism sheet 550 and the second prism sheet 560 form an optical sheet, and the optical sheet is formed of a different combination, for example, a micro lens array, or a diffusion sheet and a micro lens array. It may be made of a combination or a combination of a single prism sheet and a micro lens array.

The panel 570 may include a liquid crystal display. In addition to the liquid crystal display panel 560, other types of display devices that require a light source may be provided.

The panel 570 is in a state in which a liquid crystal is placed between the glass bodies and polarizing plates are placed on both glass bodies in order to utilize the polarization of light. Here, the liquid crystal has an intermediate characteristic between a liquid and a solid, and the liquid crystal, which is an organic molecule having fluidity like a liquid, has a state that is regularly arranged like a crystal, and the molecular arrangement is changed by an external electric field. Display an image.

A liquid crystal display panel used in a display device is an active matrix type, and uses a transistor as a switch for controlling a voltage supplied to each pixel.

A color filter 580 is provided on the front surface of the panel 570 to transmit light projected from the panel 570 and transmit only red, green, and blue light for each pixel, so that an image can be expressed.

7 is a diagram showing an embodiment of a lighting device in which a light emitting device is disposed.

The lighting device according to the present embodiment may include a cover 1100, a light source module 1200, a radiator 1200, a power supply unit 1600, an inner case 1700, and a socket 1800. In addition, the lighting apparatus according to the embodiment may further include one or more of the member 1300 and the holder 1500, and the light source module 1200 may include a light emitting device package according to the above-described embodiments. .

The cover 1100 has a shape of a bulb or a hemisphere, is hollow, and may be provided in an open shape. The cover 1100 may be optically coupled to the light source module 1200. For example, the cover 1100 may diffuse, scatter, or excite light provided from the light source module 1200. The cover 1100 may be a kind of optical member. The cover 1100 may be coupled to the radiator 1200. The cover 1100 may have a coupling portion coupled to the radiator 1200.

A milky white paint may be coated on the inner surface of the cover 1100. The milky white paint may include a diffuser that diffuses light. The surface roughness of the inner surface of the cover 1100 may be greater than the surface roughness of the outer surface of the cover 1100. This is to sufficiently scatter and diffuse light from the light source module 1200 to emit it to the outside.

The material of the cover 1100 may be glass, plastic, polypropylene (PP), polyethylene (PE), polycarbonate (PC), or the like. Here, polycarbonate is excellent in light resistance, heat resistance, and strength. The cover 1100 may be transparent so that the light source module 1200 is visible from the outside, or may be opaque. The cover 1100 may be formed through blow molding.

The light source module 1200 may be disposed on one surface of the radiator 1200. Accordingly, heat from the light source module 1200 is conducted to the radiator 1200. The light source module 1200 may include a light emitting device package 1210, a connection plate 1230, and a connector 1250.

The member 1300 is disposed on the upper surface of the radiator 1200 and has guide grooves 1310 into which a plurality of light emitting device packages 1210 and a connector 1250 are inserted. The guide groove 1310 corresponds to the substrate and the connector 1250 of the light emitting device package 1210.

The surface of the member 1300 may be coated or coated with a light reflective material. For example, the surface of the member 1300 may be coated or coated with a white paint. The member 1300 reflects light reflected on the inner surface of the cover 1100 and returning toward the light source module 1200 toward the cover 1100. Therefore, it is possible to improve the light efficiency of the lighting device according to the embodiment.

The member 1300 may be made of an insulating material, for example. The connection plate 1230 of the light source module 1200 may include an electrically conductive material. Accordingly, electrical contact may be made between the radiator 1200 and the connection plate 1230. The member 1300 is made of an insulating material to block an electrical short between the connection plate 1230 and the radiator 1200. The radiator 1200 receives heat from the light source module 1200 and heat from the power supply unit 1600 to radiate heat.

The holder 1500 blocks the receiving groove 1719 of the insulating part 1710 of the inner case 1700. Accordingly, the power supply unit 1600 accommodated in the insulating unit 1710 of the inner case 1700 is sealed. The holder 1500 has a guide protrusion 1510. The guide protrusion 1510 has a hole through which the protrusion 1610 of the power supply unit 1600 passes.

The power supply unit 1600 processes or converts an electrical signal provided from the outside and provides it to the light source module 1200. The power supply unit 1600 is accommodated in the storage groove 1919 of the inner case 1700 and is sealed inside the inner case 1700 by the holder 1500. The power supply unit 1600 may include a protrusion 1610, a guide unit 1630, a base 1650, and an extension 1670.

The guide part 1630 has a shape protruding outward from one side of the base 1650. The guide part 1630 may be inserted into the holder 1500. A number of parts may be disposed on one surface of the base 1650. A number of components include, for example, a DC converter that converts AC power provided from an external power source to DC power, a driving chip that controls the driving of the light source module 1200, and an ESD for protecting the light source module 1200. (ElectroStatic discharge) may include a protection element, but is not limited thereto.

The extension part 1670 has a shape protruding outward from the other side of the base 1650. The extension part 1670 is inserted into the connection part 1750 of the inner case 1700 and receives an electrical signal from the outside. For example, the extension part 1670 may be provided equal to or smaller than the width of the connection part 1750 of the inner case 1700. Each end of the "+ wire" and "- wire" may be electrically connected to the extension part 1670, and the other end of the "+ wire" and "- wire" may be electrically connected to the socket 1800. .

The inner case 1700 may include a molding unit together with the power supply unit 1600 therein. The molding part is a part in which the molding liquid is solidified, and allows the power supply part 1600 to be fixed inside the inner case 1700.

The embodiments have been described above, but these are only examples and do not limit the present invention, and those of ordinary skill in the art to which the present invention belongs are not illustrated above within the scope not departing from the essential characteristics of the present embodiment. It will be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And differences related to such modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

100, 200: light emitting device package 110, 210: package body
121, 221: first lead frame 122, 222: second lead frame
123, 223: third lead frame 131,231: first insulating layer
132, 232: second insulating layer 140a, 140b: first and second light emitting devices
240: light emitting element 260: dummy pad
261: substrate 263: insulating layer
265: first conductive layer 267: bonding layer
500: image display device

Claims (8)

Package body;
A first lead frame to a third lead frame exposed from a part of the package body;
A light emitting device disposed on the first lead frame; And
Including a dummy pad disposed on the package body,
The light emitting device is wire-bonded to the second lead frame and wire-bonded to the third lead frame via the dummy pad,
The dummy pad,
Board;
An insulating layer disposed on the substrate;
A first conductive layer disposed on the insulating layer; And
A light emitting device package comprising a bonding layer disposed under the substrate. The method of claim 1,
A light emitting device package in which a distance between the light emitting device and the third lead frame is greater than a distance between the light emitting device and the second lead frame. The method of claim 1,
A light emitting device package in which a cavity is formed in the package body, the cavity includes a bottom surface and a side wall, and the light emitting device is disposed on a bottom surface of the cavity. The method of claim 3,
A light emitting device package in which a second lead frame and a third lead frame are exposed to face each other in an edge region of the bottom surface of the cavity. The method of claim 4,
An insulating layer is disposed in a region between the first lead frame and the second lead frame, and in a region between the first lead frame and the third lead frame. The method according to any one of claims 1 to 5,
Each of the first conductive layer and the bonding layer has a multilayer structure including titanium, nickel, and silver. delete The method of claim 1,
The dummy pad has a length in a first direction smaller than a length in a second direction, and the second direction is a direction connecting the light emitting device and the third lead frame.

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