CN100392883C

CN100392883C - Light-emitting diode

Info

Publication number: CN100392883C
Application number: CNB2005100821288A
Authority: CN
Inventors: 杨正中; 钟长祥; 杜全成; 詹高峰; 吴仁钊
Original assignee: Epistar Corp
Current assignee: Epistar Corp
Priority date: 2005-06-29
Filing date: 2005-06-29
Publication date: 2008-06-04
Anticipated expiration: 2025-06-29
Also published as: CN1889279A

Abstract

The present invention provides a light emitting diode. It contains one lighting structure, one heterojunction, one first electrode and one second electrode; wherein said lighting structure having one top surface, first electrode and second electrode respectively located top surface, heterojunction located in lighting structure, heterojunction including one first semiconductor layer and one second semiconductor layer, first semiconductor layer and second semiconductor layer being different doping type and first semiconductor layer having one boundary, first electrode electrically connected with first semiconductor layer and including at least two joining parts, one centre of first terminal with boundary shortest horizon distance being d, 89 micrometer <= d <= 203 micrometer, second electrode electrically connected with second semiconductor layer and including one outer arm part which peripherally encompasses top surface.

Description

Light-emitting diode

Technical field

The present invention relates to a kind of light-emitting diode, particularly relate to the electrode design of light-emitting diode.

Background technology

In recent years, light-emitting diode (Light Emitting Diode; LED) production cost is low, simple in structure because of having, low power consumption, volume is little and install to be easy to advantage, little by little replace general light source, comprised but non-limitingly (instrumentation), display (displayer) and general lighting (illumination) are installed in traffic sign (traffic signaling), electronic signal (electronicsign), instrument and be used in a large number.

Fig. 1 is the simple structure top view of a kind of existing LED 10, p type electrode 110 is when applied voltage, and electric current passes p-n junction (disclosing) to n type electrode 120, because p type electrode 110 and n type electrode 120 lay respectively at the diagonal position of LED 10, apart farthest, so the light-emitting zone maximum (oblique line part) that can produce, yet, because electric current can be via different paths from p type electrode 110, as 130,140 or 150, to n type electrode 120, therefore, cause the CURRENT DISTRIBUTION inequality.Moreover this kind design because p type electrode is long to the distance of n type electrode, and only has single contact area (p type electrode) for applied voltage at large-scale LED and inapplicable, so will cause the luminous benefit of LED to reduce.

Fig. 2 A discloses another kind of existing LED 20 simple structure top views, oblique line partly is a light-emitting zone, p type electrode 210 has a plurality of p type inner arm (arm) parts that are parallel to each other, as 214 and 216, n type electrode 220 also has a plurality of n type inner arms that are parallel to each other partly, as 222,224 and 226, p

type arm portion

214 or 216, with adjacent n type arm part 222,224 or 226 spacing equates, therefore, compared to LED 10 structures of Fig. 1, electric current is short and equidistant from the distance of p type electrode 210 to n type electrodes 220 in the LED of Fig. 2 A 20 structures, provide high and output illumination uniformly, be particularly suitable for the bigger large LED of light-emitting zone area.

Yet the

LED

10,20 of prior art all exists the doubt of leakage current (currentleakage) among Fig. 1 or Fig. 2 A.The structure of the LED 20 that discloses with Fig. 2 A is an example, part sectioned view along K-K ' among the figure is shown among Fig. 2 B, if electric current (shown in arrow), can cause the leakage current in the oblique line part from the border 250 of p type electrode 210 towards p type semiconductor layer 240, influence LED 20 luminous benefits.Though emphasize electrode is placed the edge of LED in the prior art, to increase the area of light-emitting zone, the problem of leakage current still can't be avoided.To provide for the large-scale LED of output illumination, the problem of leakage current is very crucial for the enough electric current of needs.

Need a kind of LED that can provide luminous even and high output to throw light at present, especially for large-scale LED.

Summary of the invention

The invention provides a kind of light-emitting diode, solve the problem of the leakage current of prior art, and provide high and output illumination uniformly.

The invention provides a kind of light-emitting diode, comprise a ray structure, a heterojunction (heterojunction), one first electrode and one second electrode.Ray structure has a top surface, and heterojunction is arranged in ray structure, heterojunction comprises one first semiconductor layer and one second semiconductor layer, and first semiconductor layer is different doping types with second semiconductor layer, and first semiconductor layer has a border (boundary).First electrode is positioned at top surface and second electrode is positioned at second semiconductor layer.First electrode is electrically connected with first semiconductor layer and comprises at least two coupling parts, and wherein, a center of first electrode and the shortest horizontal range on border are d, 89 μ m≤d≤203 μ m.Second electrode is electrically connected with second semiconductor layer and comprises an outer arm (outer arm) part, and the outer arm part is peripherally around (peripherallyencompass) top surface.

Description of drawings

Fig. 1 discloses the simple top view of the LED of prior art;

Fig. 2 A discloses the simple top view of the LED of another prior art;

Fig. 2 B discloses the part sectioned view of the LED of Fig. 2 A;

Fig. 3 A discloses the simple top view of LED of the present invention;

Fig. 3 B discloses part sectioned view of the present invention;

Fig. 4 A discloses the input voltage VS. input current diagram of the present invention and prior art;

Fig. 4 B discloses the input current VS. power output diagram of the present invention and prior art; And

Fig. 5-9 discloses the simple top view of LED according to an embodiment of the invention.

The simple symbol explanation

10,20,30,50,60,70,80 light-emitting diodes

110,210,330,530,630,730,830,930 first electrodes (p type electrode)

120,220,340,540,640,740,840,940 second electrodes (n type electrode)

130,140,150 paths

214,216,334p type inner arm part

222,224,226,346n type inner arm partly

240,322 first semiconductor layers (p type semiconductor layer)

324 second semiconductor layers (n type semiconductor layer)

250,350,550,650,750,850,950 borders

305 base materials

310 ray structures

312 top surfaces

320 heterojunction

326 luminescence activity layers

332,342,532,632,732,832,932 coupling parts

344,544,644,744,844,944 outer arm parts

Embodiment

Fig. 3 A discloses the top view of a kind of light-emitting diode of the present invention (LED) 30, and Fig. 3 B is for prolonging I-I ' among Fig. 3 A, the part sectioned view of LED 30.LED 30 comprises a ray structure 310, a heterojunction 320, one first electrode 330 and one second electrode 340.Ray structure 310 has a top surface 312, and heterojunction 320 is arranged in ray structure 310, and being positioned at heterojunction 320 belows is base material 305.Heterojunction 320 has one first semiconductor layer 322, one second semiconductor layer 324 and a luminescence activity layer 326, wherein first semiconductor layer 322 is different doping types with second semiconductor layer 324, for instance, first semiconductor layer 322 is a p type semiconductor layer 322, and second semiconductor layer 324 is a n type semiconductor layer 324.Be respectively p type electrode and n type electrode corresponding to p type semiconductor layer 322 and n type semiconductor layer 324, the first electrodes 330 and second electrode 340, and be electrically connected with p type semiconductor layer 322 and n type semiconductor layer 324 respectively.

In an embodiment, top surface 312 areas of LED 30 of the present invention are greater than 450 μ m ², that is LED 30 is large-scale LED, in the area of another embodiment top surface 312 greater than 1000 μ m ² First electrode 330 has at least two coupling parts 332 (or claiming line connection gasket (wire bonding pad)), on large-area top surface 312, to provide the many places line to connect, for applying voltage, in Fig. 3 A, only disclose two coupling parts 332, but the present invention is intended to the coupling part is defined in two, the design of LED should be looked in the coupling part, increase along with coupling part 332, for the designer, can do more series connection, circuit design such as parallel connection, but the coupling part 332 of the present invention more than at least two is preferably four coupling parts 332 (Fig. 9), so that enough line junctions to be provided.

Second electrode 340 has coupling part 342 and outer arm (outer arm) part 344, disclose two coupling parts 342 among Fig. 3 A, but the present invention is intended to the coupling part is defined in two, coupling part 342 is used for the electric current of second electrode 340 is derived, and outer arm part 344 is peripherally around top surface 312.If the LED 30 of Fig. 3 A of the present invention is compared with the LED 20 of prior art Fig. 2 B, the outer arm part 344 that can understand LED 30 of the present invention is peripherally around top surface 312, also simultaneously first electrode 330 is surrounded fully, so, do not have the leakage problem of aforementioned prior art.Prior art LED 20 and LED 30 of the present invention electrically relatively are disclosed among Fig. 4 A, the 4B.Disclose input current VS. input voltage among Fig. 4, wherein, as can be seen when desire is imported bigger input current (or title operating current), the more existing LED of the required voltage of LED of the present invention 30 20 is little, that is the resistance of LED 30 is little than the resistance of LED 20, for instance, and when desiring input current 500mA, LED 30 of the present invention only needs input voltage 3.3volt, and existing LED 20 then needs input 3.4volt.With reference now to Fig. 4 B,, be input current VS. power output, wherein, as can be seen along with the increase of input current, the power output of LED 30 of the present invention obviously increases compared to prior art LED 20.Therefore, for the large scale LED that desires most ardently development at present, design of the present invention can meet the required big input current of large scale LED, and high power output is provided.

In the prior art for obtaining big light-emitting area with the edge of the first electrode design position at top surface, yet, according to LED 30 of the present invention (with reference to figure 3A, 3B), there is the outer arm part 344 of second electrode 340 in first electrode, 330 outsides, therefore first electrode 330 need not be near top surface 312 edges to obtain big light-emitting zone, in addition, because the making of ray structure 310, form heterojunction 320 earlier on base material 305, again with etching technique (as reactive ion etching, RIE) the etching first halfbody layer 322, the luminescence activity layer 326 and second semiconductor layer 324, at this moment, the zone on the border 350 of the close first halfbody layer 322 is easy to generate defective (defect), therefore, supplies the unsuitable close border 350, position of first electrode 330 of injection current.Yet, for avoiding electric current congested (current crowding), make electric current diffusion effect optimization, to obtain preferred luminous benefit, first electrode 330 must be near borders 350.We attempt averaging out in these two kinds of factors, we find to work as the center of first electrode 330 and distance (being d shown among Fig. 3 A, the 3B) scope at edge 350 is preferably 89 μ m (about 3.5mil)≤d≤203 μ m (about 8mil), and You Jia is 102 μ m (about 4mil)≤d≤152 μ m (about 6mil).

In an embodiment of the present invention, first electrode 330 has a plurality of parallel inner arm parts, be referred to as the first inner arm part 334, second electrode 340 also has a plurality of parallel inner arm parts, and partly 346, the first inner arm parts 334 and adjacent second inner arm partly 346 are parallel to each other and equidistantly to be referred to as second inner arm, therefore, in having the large LED of big light-emitting area, electric current is short and equidistant to the distance of second electrode 346 respectively from first electrode 334, provides high and output illumination uniformly.

Fig. 5-9 discloses the simple top view of other embodiments of the invention, wherein, with LED50 shown in Figure 5 is example, first electrode (p type electrode) 530 has at least two coupling parts 532, the distance on the border 550 of center to the first semiconductor layer of first electrode 530 is d, its scope definition is preferably 89 μ m (about 3.5mil)≤d≤203 μ m (about 8mil) as previously mentioned, is preferably 102 μ m (about 4mil)≤d≤152 μ m (about 6mil).The outer arm part 544 of second electrode (n type electrode) 540 is around its top surface 512.It is described that Fig. 6-9 is similar to Fig. 3 a, Fig. 5, and the

LED

60,70,80,90 that is disclosed in wherein comprises first electrode 630,730,830,930 respectively; Second electrode 640,740,840,940; Border 650,750,850,950; Coupling part 632,732,832,932; And outer arm part 644,744,844,944, the element that the description of these elements, function and other Fig. 3 a, Fig. 5 are occurred in preceding detailed description, does not add at this and to give unnecessary details.

The present invention is by describing as above with reference to different embodiment, and the due cognition of those skilled in the art is graphic and describes in detail for illustrative purposes only and non-limiting, and non-ly is intended to limit the invention to disclosed specific pattern and example.On the contrary, do not break away from spirit of the present invention and category, under the definition of following claim, the present invention also comprises the conspicuous modification of those skilled in the art, changes, rearranges, replaces, replacement, design alternative and embodiment.Therefore, expectedly be that following claim comprises that all advance the modification of a cloth, change, rearrange, replace, replacement, design alternative and embodiment.

Claims

1. light-emitting diode comprises:

One ray structure, this ray structure has a top surface;

One heterojunction is in this ray structure, and this heterojunction comprises one first semiconductor layer and one second semiconductor layer, and wherein this first semiconductor layer has a border, and this first semiconductor layer is different doping types with this second semiconductor layer;

One first electrode is positioned at this top surface, and this first electrode is electrically connected with this first semiconductor layer and comprises at least two coupling parts, and wherein, a center of this first electrode and the shortest horizontal range on this border are d, 89 μ m≤d≤203 μ m; And

One second electrode is positioned at this second semiconductor layer, and this second electrode is electrically connected with this second semiconductor layer and comprises an outer arm part, and this outer arm part is peripherally around this top surface.

2. light-emitting diode as claimed in claim 1, wherein 102 μ m≤d≤152 μ m.

3. light-emitting diode as claimed in claim 1, wherein this first electrode comprises a plurality of inner arm parts parallel to each other.

4. light-emitting diode as claimed in claim 1, wherein this second electrode comprises a plurality of inner arm parts parallel to each other.

5. light-emitting diode as claimed in claim 1, wherein the area of this top surface is not less than 450 μ m ²

6. light-emitting diode as claimed in claim 1, wherein the area of this top surface is not less than 1000 μ m ²

7. light-emitting diode comprises:

One ray structure, this ray structure has a top surface, and the area of this top surface is not less than 450 μ m ²

One heterojunction is in this ray structure, and this heterojunction comprises a n type semiconductor layer and a p type semiconductor layer, and wherein this p type semiconductor layer has a border;

One p type electrode is positioned at this top surface, and this p type electrode is electrically connected with this p type semiconductor layer and comprises at least two p molded lines connection gaskets, and wherein, a center of this p type electrode and the shortest horizontal range on this border are d, 89 μ m≤d≤203 μ m; And

One n type electrode is positioned at this n type semiconductor layer, and this n type electrode is electrically connected with this n type semiconductor layer and comprises a n type outer arm part, and this n type outer arm part is peripherally around this top surface.

8. light-emitting diode as claimed in claim 7, wherein n type electrode comprises at least one n molded lines connection gasket and a plurality of n type inner arm part parallel to each other.

9. light-emitting diode as claimed in claim 7, wherein this p type electrode comprises a plurality of p type inner arm parts parallel to each other.

10. light-emitting diode as claimed in claim 7, wherein 102 μ m≤d≤152 μ m.