KR101892923B1 - The light emitting device - Google Patents

Abstract

The present invention relates to a light emitting device, comprising: a first light emitting structure in which n (n? 2) light emitting cells are connected; A second light emitting structure connected in anti-parallel to the first light emitting structure and disposed above or below the first light emitting structure; And an insulating layer for insulating the first and second light emitting structures from each other. Therefore, it is possible to provide a light emitting element which emits light in all the cycles regardless of the polarity of the power source in the AC power source.

Description

TECHNICAL FIELD [0001] The present invention relates to a light emitting device,

The present invention relates to a light emitting device. In particular, the present invention relates to an alternating current light emitting device including a light emitting diode.

Light emitting diodes (LEDs) can be made of a compound semiconductor material such as GaAs-based, AlGaAs-based, GaN-based, InGaN-based, and InGaAlP-based.

Such a light emitting diode is used as a light emitting device that is packaged and emits various colors, and a light emitting device is used as a light source in various fields such as a lighting indicator, a character indicator, and an image indicator that display a color.

SUMMARY OF THE INVENTION The present invention provides a light emitting device that emits light by an AC power source.

The embodiment includes a first light emitting structure in which n (n? 2) light emitting cells are arranged in a matrix and connected in series; A first pad disposed in a first corner region of the first light emitting structure and a second pad disposed in a second corner region opposite to the first corner region; A second light emitting structure connected in anti-parallel to the first light emitting structure and spaced apart from the first light emitting structure on the first light emitting structure; And a second insulating layer disposed between the first and second light emitting structures for insulating the first and second light emitting structures from each other, the light emitting cell including a first conductive semiconductor layer, A conductive semiconductor layer, a first active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer, And a first insulating layer including an opening for exposing a part of the first conductive type semiconductor layer, the first insulating layer including a first transparent electrode layer disposed on the second conductive type semiconductor layer, Wherein the second light emitting structure includes a third conductive semiconductor layer, a fourth conductive semiconductor layer, a third conductive semiconductor layer, a second conductive semiconductor layer, and a third conductive semiconductor layer, A second active layer disposed between the first conductive semiconductor layer and the fourth conductive semiconductor layer; A second transparent electrode layer under the fourth conductive type semiconductor layer; And an electrode layer disposed under the exposed third conductive type semiconductor layer, wherein a first connection protrusion is disposed on the first pad and is electrically connected to a second light-transmitting electrode layer of the second light-emitting structure, Emitting device arranged on the second pad and electrically connected to the electrode layer of the second light-emitting structure.

The embodiment can provide a semiconductor light emitting device driven by an AC power source.

Embodiments can provide a light emitting device that emits light in all cycles regardless of the polarity of a power source in an AC power source.

1 is a circuit diagram of a light emitting device according to a first embodiment of the present invention.
2 is a top view of the light emitting chip of FIG.
3 is a cross-sectional view of the light emitting chip of FIG. 2 taken along line I-I '.
4 is a cross-sectional view of the light emitting chip of FIG. 2 taken along line II-II '.
Figs. 5 and 6 are views for explaining the driving of the light emitting chip of Fig. 2. Fig.
7 is a cross-sectional view illustrating a light emitting device package including the light emitting chip of FIG.
8 is a cross-sectional view showing another light emitting device package including the light emitting chip of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between .

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

In addition, the upper or lower reference of each component is described with reference to the drawings. The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size of each component does not entirely reflect the actual size.

In the description of embodiments according to the present invention, it is to be understood that where an element is described as being formed "on or under" another element, On or under includes both the two elements being in direct contact with each other or one or more other elements being indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

Hereinafter, a light emitting device according to the present invention will be described with reference to FIGS. 1 to 6. FIG.

FIG. 1 is a circuit diagram of a light emitting device according to a first embodiment of the present invention, FIG. 2 is a top view of the light emitting chip of FIG. 1, FIG. 3 is a sectional view taken along line I- FIG. 4 is a cross-sectional view of the light emitting chip of FIG. 2 taken along line II-II ', and FIGS. 5 and 6 are views illustrating driving of the light emitting chip of FIG.

Referring to FIG. 1, the four light emitting device packages 100-130 connected to the AC power source 150 are shown as two light emitting diodes which are inversely parallel to each other. However, the two light emitting diodes It does not.

The first light emitting device package 100 and the second light emitting device package 110 are connected in series between the first node n1 and the second node n2 and the third light emitting device package 120 and fourth The light emitting device package 130 is connected in series between the first node n1 and the second node n2 and the first and second light emitting device packages 100 and 110 and the third and fourth light emitting device packages 130, (120, 130) may be connected in a reverse direction.

The number of the light emitting device packages 100-130 between the first node n1 and the second node n2 may be determined according to the driving voltage of the ac power supply 150 and the light emitting device package 100-130.

An AC power source 150 is connected between the first node n1 and the second node n2 and a resistor for matching is connected between the AC power source 150 and the first node n1 or the second node n2. (R1) or a capacitor or the like may be connected.

As shown in FIG. 1, when the first and second light emitting device packages 100 and 110 and the third and fourth light emitting device packages 120 and 130 are connected in parallel in opposite directions, the first and second light emitting device packages 100, and 110 and the third and fourth light emitting device packages 120 and 130 operate in opposite directions.

At this time, the first to fourth light emitting device packages 100 to 130 each have one light emitting chip.

Each of the light emitting chips has two light emitting structures that operate opposite to each other, thereby generating light in all the cycles. That is, when the first light emitting structure of the first and second light emitting device packages 100 and 110 operates, the second light emitting structure of the third and fourth light emitting device packages 120 and 130 operates, The first light emitting structure of the third and fourth light emitting device packages 120 and 130 operates when the second light emitting structure of the first and second light emitting device packages 100 and 110 operates.

Hereinafter, the structure of the light emitting device will be described with reference to FIGS. 2 to 4. FIG.

Each of the light emitting device packages 100-130 includes at least one light emitting chip, and each light emitting chip includes a first light emitting structure 300 having a plurality of light emitting diodes (LEDs) And a second light emitting structure 400 disposed on the first light emitting structure 300.

The first light emitting structure 300 may include a plurality of light emitting diodes (OLEDs), and the light emitting cells may be arranged in a matrix.

The light emitting cell may include, for example, twelve light emitting diodes.

In the light emitting chip 300, two pads 370 and 480 are formed in an edge area.

A plurality of light emitting cells are arranged on a substrate 310.

The plurality of light emitting cells are arranged in a matrix form on the substrate 310. When the number of light emitting cells is 12, the light emitting cells may have a matrix shape of 3X4, and the light emitting cells, in which the pads 370 and 480 are formed, It is possible to have a larger area.

The substrate 310 may be an insulated or electrically conductive substrate 310 and may be, for example, sapphire or silicon carbide (SiC).

Each of the light emitting cells includes a first conductivity type semiconductor layer 320, a second conductivity type semiconductor layer 340 located on one region of the first conductivity type semiconductor layer 320, 320 and the second conductive semiconductor layer 340. The active layer 330 may be formed of a conductive material.

The first and second conductive semiconductor layers 320 and 340 are n-type and p-type, or p-type and n-type, respectively.

The first conductive semiconductor layer 320, the active layer 330 and the second conductive semiconductor layer 340 may be formed of a gallium nitride semiconductor material, that is, (B, Al, In, Ga) N.

The first conductive semiconductor layer 320, the active layer 330 and the second conductive semiconductor layer 340 may be formed of a compound semiconductor of Group 3-VI elements such as GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, and the like. When the first conductive type is an N-type semiconductor, the second conductive type may be a P-type semiconductor, and the second conductive type may be formed in the opposite manner. And a third conductive semiconductor layer, that is, an N-type semiconductor layer or a P-type semiconductor layer, is formed under the second conductive semiconductor layer. Accordingly, the light emitting structure 300 may be implemented by any one of N-P, P-N, N-P-N, and P-N-P junction structures.

When the first conductive semiconductor layer 320 is an N-type semiconductor, an n-type dopant (e.g., Si, Ge, Sn, Se, or Te) is doped.

The second conductive semiconductor layer 340 may be formed under the active layer 330 and may be doped with a P-type dopant such as Mg, Be, or Zn.

The spaces between the light emitting structures 300 are separated from each other through a predetermined space, and are electrically separated.

A buffer layer (not shown) may be further provided between the substrate 310 and the first conductivity type semiconductor layer 320.

In addition, a plurality of patterns can be formed on the surface of the substrate 310, and light can be scattered by the plurality of patterns, so that the luminous efficiency can be increased.

A light transmitting electrode layer 350 is formed on the second conductive semiconductor layer 340.

The light-transmitting electrode layer 350 transmits light generated in the active layer 330 and distributes and supplies a current to the second conductive type semiconductor layer 340.

The light transmissive electrode layer 350 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (TiO2), AuO2 / Au, ITO, NiO, AuO, ITO, AZO, AZO, ATO, GZO, IrOx, RuOx, RuOx / ITO, ), A conductive nitride (TCN), or the like.

The active layer 330 may be a semiconductor layer formed of a multiple quantum well structure.

A conductive clad layer may be formed on and / or below the active layer 330.

In this case, the lamination structure on the first conductivity type semiconductor layer 320 is formed to have a narrower area than the top surface of the first conductivity type semiconductor layer 320, and each light emitting cell has a first upper surface And a second upper surface on which the first conductive semiconductor layer 320 is exposed.

A first insulating layer 390 is formed on the light emitting chip and a first insulating layer 390 is formed on the light transmitting electrode layer 350 and on the second upper surface of the first conductive semiconductor layer 320, .

A wiring 365 is formed on the first insulating layer 390 to connect the opening for exposing the first conductivity type semiconductor layer 320 and the opening for exposing the transparent electrode layer 350 of a neighboring cell, In series.

The wiring 365 is selected from the group consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, Hf, W, Ti, . Such a wiring 365 is electrically ohmic-contacted and can function as a reflective electrode layer having a high reflectance (for example, 50% or more).

A second insulating layer 395 may be formed on the entire surface of the chip to cover the wiring 365. The second insulating layer 395 prevents the wiring 365 from being contaminated by moisture or the like, The wiring 365 and the light emitting cells are prevented from being damaged.

On the other hand, a first connection protrusion 380 connected to the first conductive type semiconductor layer 320 is formed on the second upper surface.

That is, the first connection protrusion 380 is formed on the first pad 370 on the first conductive semiconductor layer 320 and is electrically connected to the transparent electrode layer 440 of the second light emitting structure 400.

The connection protrusions 380 may be formed only on the first pad 370 as shown in FIGS. 2 to 4. Alternatively, the connection protrusions 380 may be formed on the second upper surface of the first conductive semiconductor layer 320, The distance between the second light emitting structure 300 and the second light emitting structure 400 can be maintained.

The first connection protrusion 380 may be formed of the same material as the first pad 370, but may be formed thicker than the first pad 370.

The first pad 370 may be formed in the first cell and the second pad 480 may be formed in the last cell.

In this case, the first cell is defined as a start point of a serial connection, and the last cell is defined as an end point of a serial connection.

As described above, since a plurality of cells formed in one light emitting chip are formed in the same structure, and a plurality of cells in one light emitting chip are connected in series and simultaneously driven, the connection between the cells is simplified and the number of masks used is reduced The manufacturing process is simple and economical.

Moreover, since the connection of the wiring 365 in the light emitting chip is simplified, the leakage current is reduced, so that the device reliability can be secured.

On the other hand, the side walls of the light emitting cells are inclined with respect to the upper surface of the substrate 310, and the width of the side walls may become narrower toward the upper side. The inclination of the sidewalls improves the emission efficiency of the light generated in the active layer 330 and helps conformal deposition of other layers to be formed on the light emitting cells.

Meanwhile, the present invention further includes a second light emitting structure 400 on the first light emitting structure 300.

The second light emitting structure 400 forms one light emitting cell that is not physically separated and functions as a power LED.

The second light emitting structure 400 may have a smaller size than the first light emitting structure 300 and may have the same size.

The second light emitting structure 400 includes a first conductive semiconductor layer 410, an active layer 420, a second conductive semiconductor layer 430, and a transparent electrode layer 440 on a substrate, .

The structure of the first conductivity type semiconductor layer 410 to the light-transmitting electrode layer 440 may be the same as or similar to the structure of each cell of the first light emitting structure 300.

The transparent electrode layer 440 may be in the shape of a stripe extending from the second pad 480 and running on a region corresponding to the first light emitting structure 300, as shown in FIG.

The second light emitting structure 400 has a step to expose the first conductivity type semiconductor layer 410 in a region corresponding to the light transmitting electrode layer 350 of each light emitting cell of the first light emitting structure 300.

The second light emitting structure 400 is disposed so that the light transmitting electrode layer 440 faces the light transmitting electrode layer 350 of the first light emitting structure 300.

Accordingly, the first conductive semiconductor layer 410 may be disposed on the uppermost portion. Alternatively, the first conductive semiconductor layer 410 may include a growth substrate.

 As shown in FIGS. 3 and 4, the second light emitting structure 400 has one light emitting cell, exposes the first conductive semiconductor layer 410 with a step in a region corresponding to the first light emitting structure 300 And an electrode layer 470 on the exposed first conductivity type semiconductor layer 410.

The electrode layer 470 is formed in a stripe shape, and the light transmitting electrode layer 440 is formed to face each other to help spread the current.

And a second connection protrusion 471 connecting the electrode pad 470 and the second pad 480.

In order to expose the first and second pads 370 and 480 formed in the first light emitting structure 300 when the second light emitting structure 400 is disposed on the first light emitting structure 300, And may have a recessed surface 401 in which the edge region of the structure 400 is recessed.

That is, the first connection protrusion 380 electrically connects the first pad 370 of the first light emitting structure 300 and the light transmitting electrode layer 440 of the second light emitting structure 400, and the second connection protrusion 471 Are electrically connected to the second pad 480 of the first light emitting structure 300 and the electrode layers of the second light emitting structure 300 so that the two light emitting structures 300 and 400 are connected in reverse parallel.

An insulating layer 490 for insulating the first light emitting structure 300 from the first light emitting structure 400 is further formed on the surface of the second light emitting structure 400.

2 to 4 illustrate that the first light emitting structure 300 having a plurality of separated cells is disposed at the lower portion. Alternatively, the first light emitting structure 300 may be disposed at the upper portion of the second light emitting structure 400 It is obvious that it can be deployed.

5A, when a negative voltage is applied to the second pad 480 for a half period (0 to T / 2) of the AC power supply 150 and a positive voltage is applied to the first pad 370, Likewise, the first light emitting structure 300 does not emit light in the reverse direction due to the current flow in the reverse direction, and the second light emitting structure 400 proceeds to emit light in a forward current.

Next, when a positive voltage is applied to the second pad 470 and a negative voltage is applied to the first pad 370 during the next half cycle (T / 2 to T) of the AC power source 150 as shown in FIG. 6A As shown in FIG. 6B, the first light emitting structure 300 has a plurality of cells connected in series through a forward current, and the first light emitting structure 300 emits light. At this time, the second light emitting structure 400 does not emit light due to the reverse current flow.

Therefore, since the light emission proceeds in all the periods in one light emitting chip, the light emitting chip always emits light to the AC power source.

As shown in FIG. 1, a plurality of light emitting device packages 100-130 having the light emitting chip are connected in reverse parallel to each other, so that different light emitting structures of neighboring light emitting chips can emit light during a half period.

7 and 8 are side cross-sectional views showing a light emitting device package.

Referring to FIG. 7, the light emitting device package 200 includes a semiconductor light emitting device 100, a package body 210 having a cavity 213, and a plurality of lead frames 231 and 230 as a side view type package.

The semiconductor light emitting device 100 is the light emitting chip of FIGS. 2 to 4, and the semiconductor light emitting device 100 may be arranged in one, or a plurality of the light emitting chips may be arranged in series, parallel or anti-parallel.

The semiconductor light emitting device 100 is disposed in a cavity 213 formed on the package body 210. The cavity 213 is formed with a plurality of lead frames 231 and 230 open, The semiconductor light emitting device 100 is attached to the frame 231 as a conductive adhesive. Both ends of the lead frames 230 and 231 function as external electrodes 232 and 233, respectively.

The semiconductor light emitting device 100 may be connected to the lead frame 230 by a wire 215 to receive power. Here, when a plurality of semiconductor light emitting elements are disposed in the cavity 213, they may be connected to each other by wires, but the present invention is not limited thereto.

A transparent resin such as silicon or epoxy may be formed in the cavity 213. In addition, the cavity 213 may be formed with a resin added with a phosphor. Further, the side surface of the cavity 213 is formed to be inclined, thereby improving the amount of reflection of light. The package body 210 may be mounted on a substrate (not shown) to provide a side view light emitting device.

Referring to FIG. 8, the light emitting device package 200A is a top view package. The light emitting device package 200A includes a package body 310 made of silicon, a plurality of electrode layers 310 and 314, and a semiconductor light emitting device 100.

A plurality of electrode layers 310 and 314 electrically opened are formed on the surface of the package body 310. Other layers such as a seed layer or an insulating layer may be formed between the electrode layers 310 and 314 and the package body 310, but the present invention is not limited thereto.

A cavity 311 is formed on the package body 310 and the semiconductor light emitting device 100 is attached to one of the electrode layers 310 exposed through the cavity 311 with a conductive adhesive.

The semiconductor light emitting device 100 is connected to the electrode layer 314 by a wire 315.

The semiconductor light emitting devices 100 may be mounted in a single unit or a plurality of units. The plurality of semiconductor light emitting devices 100 may be connected in series, or may be connected in parallel or anti-parallel. The light emitting device may be implemented as a top view type light source by receiving power from a back surface of the package body 310 and driving the semiconductor light emitting device.

The wiring pattern, the lead frame, the electrode layer, the wire, and the like of the substrate can be selectively included as the connecting means for connecting the plurality of semiconductor light emitting elements to each other.

The semiconductor light emitting device according to the embodiment may be provided as a light unit in a portable terminal, a notebook computer, or the like, or may be variously applied to a lighting device and a pointing device.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

The light emitting device package 100, 110, 120, 130
The first light emitting structure 300
The second light emitting structure 400
AC power 150

Claims (11)

a first light emitting structure in which n (n? 2) light emitting cells are arranged in a matrix and connected in series;
A first pad disposed in a first corner region of the first light emitting structure and a second pad disposed in a second corner region opposite to the first corner region;
A second light emitting structure connected in anti-parallel to the first light emitting structure and spaced apart from the first light emitting structure on the first light emitting structure; And
And a second insulating layer disposed between the first and second light emitting structures to isolate the first and second light emitting structures from each other,
The light emitting cell includes a first conductive semiconductor layer, a second conductive semiconductor layer, a first active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer, And
And a first light-transmitting electrode layer disposed on the second conductive type semiconductor layer,
And a first insulating layer including an opening exposing a part of the first conductive type semiconductor layer,
And a wiring connecting the first conductive semiconductor layer exposed by the opening and the first transparent electrode layer of the neighboring light emitting cell,
The second light-
A third conductive type semiconductor layer, a second active layer disposed between the third conductive type semiconductor layer and the fourth conductive type semiconductor layer;
A second transparent electrode layer under the fourth conductive type semiconductor layer; And
And an electrode layer disposed under the exposed third conductive type semiconductor layer,
The first connection protrusion is disposed on the first pad and electrically connected to the second transparent electrode layer of the second light emitting structure,
And the second connection protrusion is disposed on the second pad and is electrically connected to the electrode layer of the second light emitting structure. The method according to claim 1,
The first conductive semiconductor layer and the third conductive semiconductor layer are doped with the same dopant,
Wherein the second conductivity type semiconductor layer and the fourth conductivity type semiconductor layer are doped with the same dopant. 3. The method of claim 2,
Wherein the first pad is disposed in a first light emitting cell of the first light emitting structure arranged in a matrix,
And the second pad is disposed in a last light emitting cell of the first light emitting structure arranged in a matrix. The method of claim 3,
Wherein the first light-transmitting electrode layer of the first light-emitting structure and the second light-transmitting electrode layer of the second light-emitting structure are disposed so as to face each other. The method according to claim 1,
Wherein the second light emitting structure has an area smaller than that of the first light emitting structure. 6. The method of claim 5,
Wherein the second light emitting structure includes a recessed surface in which an edge region is recessed to expose the first pad and the second pad. The method according to claim 6,
And a corner area of the second light emitting structure having the recessed surface corresponds to the first corner area and the second corner area of the first light emitting structure. delete delete delete delete

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