CN102610626A

CN102610626A - Alternating-current LED device with Wheatstone bridges and manufacturing method thereof

Info

Publication number: CN102610626A
Application number: CN2012100626567A
Authority: CN
Inventors: 肖德元; 张汝京; 宋天泰
Original assignee: Enraytek Optoelectronics Co Ltd
Current assignee: Enraytek Optoelectronics Co Ltd
Priority date: 2012-03-09
Filing date: 2012-03-09
Publication date: 2012-07-25

Abstract

The invention provides a manufacturing method for an alternating-current LED device with Wheatstone bridges. The manufacturing method includes steps: providing a substrate with serially connected LEDs; cutting the substrate to obtain a plurality of first LED modules and a plurality of second LED modules; and using the first LED modules as bridge arms and using the second LED modules as intermediate arms so that the alternating-current LED device with the Wheatstone bridges is formed. The ratio of the quantity of the first LED modules to the quantity of the second LED modules is smaller than or equal to 4:1, and the area of each second LED module is smaller than that of each first LED module. The invention further provides the alternating-current LED device with the Wheatstone bridges. The alternating-current LED device with the Wheatstone bridges and the manufacturing method aim to solve problems of low yield and high manufacturing cost when an alternating-current LED device is manufactured, the Wheatstone bridges with consistent technological parameters can be manufactured, the problem that parameters of various bridge arms of existing Wheatstone bridges are inconsistent is solved, various interference factors can be mutually offset easily, and system errors in the alternating-current LED device are reduced.

Description

Wheatstone bridge AC LED device and manufacturing approach thereof

Technical field

The invention belongs to luminescent device and make the field, relate in particular to a kind of AC LED device and manufacturing approach of forming by the Wheatstone bridge of directly putting into the row encapsulation through wafer on the plate thereof.

Background technology

Because the high speed development of semiconductor integrated technology, be that (Light Emitting Diode, application LED) is more and more wider for the light-emitting diode of material with the III group-III nitride.The upgrading of using along with LED, market make LED develop towards the direction of high power, high brightness for the demand of LED.

And traditional led chip generally adopts the semiconductor device of low-voltage, big current work; Must provide the suitable direct current (DC) could be normally luminous, and the power supply that normal lighting uses be high-voltage alternating (AC), so must use the technology of step-down to obtain lower voltage; Commonly used is transformer or Switching Power Supply step-down; AC is transformed into DC, is transformed into dc constant current power supply again, impel the LED device luminous.Therefore, the system entails of DC driven LED device comprises transformation part and power rectifier part, has directly raised the price of LED light fixture, and the paces that make LED get into general illumination slow down.In addition; As shown in Figure 1, transformer 100 (transformer comprises transformation part and power rectifier part) has been installed by the system of DC driven LED device, its exchange, when changing between the direct current; All there is the loss of energy in its system on interchange 102 to transformer 100, transformer 100 inside, transformer 100 to the lead 106 between the DC driven LED104; Especially exchange 102 to the conductor spacing between the transformer 100 long (distance surpasses 300Km (km)), therefore, the loss of energy is maximum; The summation of the loss of these energy reaches the power consumption of its gross energy 15%～30%, and system effectiveness is difficult to accomplish more than 90%.

Adopt interchange direct driving LED (AC LED) device luminous,, need not load the high transformer of cost with respect to traditional DC LED; Can the alternating current of the direct plug-in of LED device in 220V (or 110V) be thrown light on; And the internal system structure is simplified greatly, exchange 102 to transformer 100, transformer 100 inside thereby reduced, the energy loss on transformer 100 to the lead 106 between the DC driven LED104; AC system efficient can reach more than 90%; It is about 40%～20% that heating reduces, and its useful life, general DC LED was long a lot, as shown in Figure 2.

In the room lighting field, use usually the high-voltage LED module as 2-10W (watt) light source use, as shown in Figure 3.If think that the lighting power of light source device is more powerful, can use the direct-current LED that carries out connection in series-parallel system through the high-voltage LED module, but can not carry out the AC LED of simple connection in series-parallel system through the high-voltage LED module; Because; The key problem in technology of AC LED is the specific arrangement combination technique of LED crystal grain when encapsulation, comprises the diode characteristic double as rectification that utilizes the LED PN junction, through semiconductor fabrication process a plurality of crystal grain is integrated on the single-chip; It is high power single crystal grain LED technology; And adopt staggered matrix form to arrange technology and form bridge circuit, but make AC electric current two-way admittance, realize luminous.

With a kind of existing AC LED device making technics is example, referring to Fig. 4, and a plurality of LED micromeritics; Wherein four LED micromeritics are for use in reservation; Remaining LED micromeritics is divided into the n group, and every group is carried out the head and the tail series connection successively, and every group of LED micromeritics string of series connection from beginning to end carries out parallel connection again; Then, described parallel connection respectively organized the LED micromeritics string resistance R 0 of connecting again; Then; Four LED micromeritics that keep are formed a rectifier bridge (REC); The negative electrode of four LED micromeritics is divided into two ports respectively as these rectifier bridge two ends; What connect the resistance R 0 of having connected respectively organizes LED micromeritics string, and the anode of four LED micromeritics is divided into two ports as this rectifier bridge two ends in addition, connects current source Eac.The effect of this rectifier bridge and resistance R 0 converts direct current into exchanging, and works under alternating voltage with the many groups LED micromeritics string that drives its connection.But each the LED micromeritics in the rectifier bridge forms on silicon substrate, and is therefore, when rectifier bridge and R0 use as driver, bigger than the energy loss that rectifier bridge produced that on Sapphire Substrate, forms; In addition, every group of LED micromeritics ganged up the different process LED micromeritics series connection formation of preparation down one by one, and therefore, cost of manufacture is high; And four LED micromeritics forming this rectifier bridge exchange, in the switching process of direct current conversion, itself is also in that to carry out the oneself luminous, this device is not utilized, and can become a kind of loss of energy yet.

At present, propose on substrate a plurality of LED micromeritics of preparation in the prior art, a plurality of LED micromeritics have been carried out the connection of solid crystalline substance and electrode according to the Wheatstone bridge structure, formation AC LED on the substrate then.Each LED of said Wheatstone bridge structure prepares in same manufacturing process though form,, its whole Wheatstone bridge AC LED can damage because of a certain LEDs, and yields is low, and manufacturing cost is high; And in the process of forming the Wheatstone bridge structure, four brachium pontis ratios of Wheatstone bridge are inconsistent, and each brachium pontis parameter is inconsistent, can not cancel out each other to various disturbing factors.

In order to address the above problem; Need seek under a kind of prerequisite that can take into account the yields that improves AC LED device, reduce manufacturing cost; Can eliminate the process of the inconsistent interference method that causes of Wheatstone bridge brachium pontis technological parameter again, to solve the problem that yields was low, manufacturing cost is high when AC LED device was made.

Summary of the invention

The purpose of this invention is to provide a kind of Wheatstone bridge AC LED device and manufacturing approach thereof; To solve the problem that yields was low, manufacturing cost is high when AC LED device was made; Can prepare the consistent Wheatstone bridge of brachium pontis technological parameter again; To eliminate the inconsistent problem of its each brachium pontis parameter, easily various disturbing factors are cancelled out each other, reduce the systematic error in the AC LED device.

For addressing the above problem, the invention provides a kind of manufacturing approach of Wheatstone bridge AC LED device, comprise the steps: to provide the substrate of the LED with series connection; Said substrate is cut; Obtain a plurality of first led modules and second led module; Wherein, Each first led module comprises two LED at least with each second led module, and the quantity ratio of said first led module and second led module was smaller or equal to 4: 1, and the area of said second led module is greater than the area of said first led module; Said first led module is packaged into Wheatstone bridge AC LED device as brachium pontis and said second led module as intermediate arm.

Further, before said substrate cut, the LED of said series connection is tested, and optionally the substrate of the LED of said series connection is carried out laser scribing according to test result.

Further, have the manufacturing approach of substrate of the LED of series connection, comprise the steps:

One substrate is provided, on said substrate, forms N type limiting layer, epitaxial loayer and P type contact electrode layer from the bottom to top successively; Make at least nine isolated grooves that run through P type contact electrode layer, epitaxial loayer, N type limiting layer, above substrate, to isolate at least ten zones, the corresponding LED in each zone; In each said zone, make a N type contact electrode step that is connected with isolated groove, said N type contact electrode step runs through P type contact electrode layer, epitaxial loayer; At the surface of P type contact electrode layer, N type contact electrode step and the inner surface deposit dielectric layer of isolated groove; Remove the part spacer medium layer that is close to each isolated groove through photoetching, etching technics; Expose part P type contact electrode layer and part N type limiting layer respectively; Plated metal in part P type contact electrode layer, part N type limiting layer and the isolated groove that is exposed and on the isolated groove surface; N electrode, the P electrode and being used to of producing once out is connected the interconnect metal of the electrode of adjacent LED, forms the substrate of the LED with series connection.

Preferably, form the processing step of substrate of the LED with series connection after, the said substrate of attenuate.

Preferably, before forming N type limiting layer on the said substrate, also comprise: on said substrate, form the nitride resilient coating.

Further, said epitaxial loayer comprises multiple quantum well active layer and is formed at the P type limiting layer on the multiple quantum well active layer.

Preferably, on said N type limiting layer, form in the step of said epitaxial loayer, before forming P type limiting layer, also comprise: deposition P type nitride layer.

Preferably, said N type contact electrode platform runs through P type contact electrode layer, epitaxial loayer and extends in the part N type limiting layer.

Preferably, said N electrode, P electrode are identical with the employed electric conducting material of interconnect metal.

Preferably, the material of said N electrode, P electrode and interconnect metal is the nickel billon, or the chromium billon.

Preferably, adopting on the plate wafer directly to adorn encapsulates said first led module and second led module.

Preferably, form after the Wheatstone bridge AC LED device, also comprise: on said Wheatstone bridge AC LED device, apply fluorescent powder silica gel.

According to a further aspect in the invention; Also proposed a kind of Wheatstone bridge AC LED device, comprised four first led modules and one second led module, said first led module is as brachium pontis; Said second led module is as intermediate arm; Each first led module comprises at least two LED respectively with each second led module, and wherein, the area of said second led module is greater than the area of said first led module.

Visible by technique scheme; Compare with the AC LED manufacturing process of traditional common; The manufacturing approach of Wheatstone bridge AC LED device disclosed by the invention; The present invention cuts the substrate of the LED with series connection that same technology forms, obtains first led module and second led module of different numbers, forms Wheatstone bridge as the brachium pontis and second led module as intermediate arm by first led module then; The Wheatstone bridge that the LED micromeritics of preparation of comparing under the different process forms has reduced the cost of AC LED element manufacturing; Compare with the Wheatstone bridge of integrated manufacturing under the same technology; The present invention propose behind the LED that has made series connection on the substrate; Also need the LED micromeritics that on substrate, makes is tested before forming Wheatstone bridge, avoid bad LED micromeritics, prepare first led module and second led module; Thus it is clear that, improved the yield of product further; And; When changing appearred in each LED on the brachium pontis of the Wheatstone bridge through the present invention preparation, because four brachium pontis ratios of Wheatstone bridge are consistent, each brachium pontis parameter was consistent; The influence of various interference is cancelled out each other easily, thereby also reduces the systematic error in the AC LED device.In addition, the positive half cycle that the AC LED device that said Wheatstone bridge is formed can form interchange is luminous along the LED on two brachium pontis and the intermediate arm, and negative half period is luminous along the LED on other two brachium pontis and the same intermediate arm; Therefore; Each LED on four brachium pontis is luminous by turns, and each LED of intermediate arm because of shared always at luminous AC LED device, because the area of said second led module is greater than the area of said first led module; Therefore; Can the luminous intensity of disperseing at the light that LED sent of intermediate arm work always, making to send on the unit projected area on the intermediate arm be reduced, with the luminous intensity on four brachium pontis of balance.

Description of drawings

Fig. 1 is the structural representation that the direct-current LED device exchanges in the prior art, direct current is changed;

Fig. 2 is the structural representation that the AC LED device exchanges in the prior art, direct current is changed;

Fig. 3 is prior art mesohigh led module utilization field figure;

Fig. 4 is the rectifier bridge structural representation that the driving LED device works under alternating voltage that combines with resistance in the prior art;

Fig. 5 is the method flow sketch map of the Wheatstone bridge AC LED device of one embodiment of the invention;

Fig. 6 a to Fig. 6 g is the structural representation of manufacturing approach of the Wheatstone bridge AC LED device of one embodiment of the invention;

Fig. 7 is the method flow sketch map of substrate of the LED with series connection of Fig. 5;

Fig. 8 a to Fig. 8 g is the structural representation of manufacturing approach of substrate of the LED with series connection of Fig. 7.

Embodiment

For make above-mentioned purpose of the present invention, feature and advantage can be more obviously understandable, does detailed explanation below in conjunction with the accompanying drawing specific embodiments of the invention.

A lot of details have been set forth in the following description so that make much of the present invention.But the present invention can implement much to be different from alternate manner described here, and those skilled in the art can do similar popularization under the situation of intension of the present invention, so the present invention does not receive the restriction of following disclosed practical implementation.

Secondly, the present invention utilizes sketch map to be described in detail, when the embodiment of the invention is detailed; For ease of explanation; The profile of expression device architecture can be disobeyed general ratio and done local the amplification, and said sketch map is instance, and it should not limit the scope of the present invention's protection at this.The three dimensions size that in actual manufacturing, should comprise in addition, length, width and the degree of depth.

Be example with a kind of AC LED device shown in Fig. 6 g below; In conjunction with accompanying drawing 6a to 6g; The manufacturing approach that only has a Wheatstone bridge AC LED device with manufacturing is that example is described in detail, yet those skilled in the art should know how this method is applied to make the AC LED device that has a plurality of Wheatstone bridge connection in series-parallel and form.Described method comprises the steps:

S100: the substrate that the LED with series connection is provided.

Referring to Fig. 6 a, a substrate 600 with at least ten LED of series connection is provided, said substrate 600 can be a Sapphire Substrate, has the isolated groove 614 that above said substrate, prepares between each LED.

S101: said substrate is cut; Obtain a plurality of first led modules and second led module; Wherein, Each first led module comprises two LED at least with each second led module, and the quantity ratio of said first led module and second led module was smaller or equal to 4: 1, and the area of said second led module is greater than the area of said first led module.

Referring to Fig. 6 b; At first; Because LED generally generally adopts sapphire to make substrate in order to support the manufacture process of whole LED when making; After said each LED formed, adopting cmp (CMP) technology that substrate 600 is thinned to thickness was 50 μ m～90 μ m, is beneficial to subsequent technique wafer is cut scribing.

Secondly, a plurality of LED to said series connection test again.According in general light characteristic test, electrical characteristics test, thermal characteristic test, reliability testing or other the common LED test one or more full wafer wafer is tested, be not described in detail, but those skilled in the art are still and know at this.

Then, according to of the property sort of above-mentioned test result, for example: because the underproof crystal grain that the defective in the wafer manufacturing process forms with the full wafer wafer; Or test result does not meet the crystal grain that one or more characteristics design require; Or test result does not meet concrete parameter in the middle of the specific character, such as the crystal grain that does not meet the luminous flux performance in the LED light characteristic.Or the LED micromeritics that do not meet LED photoelectric characteristic defective to test result then repaired as step is recoverable through reparation, demotes or discard processing as if what can not repair.Need to prove that foregoing description also is not used in qualification the present invention, those skilled in the art also can carry out other distortion according to content disclosed by the invention, for example can carry out the laser scribing of other form according to said test result to said a plurality of LED unit chip.

Then; Avoiding the bad LED micromeritics of photoelectric properties according to said test result optionally cuts the substrate of LED with series connection; Obtain first led module 632 and second led module 634, improved the rate of finished products of first led module and second led module, wherein; The quantity ratio of said first led module 632 and said second led module 634 was smaller or equal to 4: 1, and the area of said second led module 634 is greater than the area of said first led module 632.And each said first led module comprises at least two LED with each said second led module.

More preferably, described first led module 632 and second led module 634 are cut into the right angle quadrangle.

S102: said first led module is formed Wheatstone bridge AC LED device as brachium pontis and said second led module as intermediate arm.

At first; Referring to Fig. 6 c; Get four modules and get a module as one group from a plurality of first led modules from a plurality of second led modules, to each LED and the 2nd LED carry out chip on board directly adorn (Chip On Board, COB); Be provided with substrate holder 638 on the said COB, on said substrate holder 638, be provided with electrode of substrate 640.The respective electrode of the introducing injection current in said electrode of substrate 640 and said first led module and said second led module is carried out solid brilliant technology earlier, i.e. the making of salient point soldered ball 636 connects through 642 bonding technologies that go between again; Form Wheatstone bridge AC LED device; Shown in Fig. 6 d, Wheatstone bridge AC LED device has four brachium pontis and an intermediate arm, wherein; Said first led module is as brachium pontis, and said second led module is as intermediate arm.When carrying out lead key closing process,, between solid brilliant some A-C, B-C, D-B and D-A, form four brachium pontis respectively, between solid brilliant some D-C, form intermediate arm referring to Fig. 6 d corresponding vertical view 6e or vertical view 6f.

Through the AC LED device of forming with Wheatstone bridge; If (not shown) during external AC power supply between solid brilliant some A-B; The positive half cycle that can form interchange is luminous along the LED on two brachium pontis (D-A and A-C) and the intermediate arm (C-D); Negative half period is luminous along the LED on other two brachium pontis (D-B and B-C) and the same intermediate arm (C-D), shown in Fig. 6 d.Therefore; Each LED on four brachium pontis is luminous by turns, and each LED of intermediate arm because of shared always at luminous AC LED device, because the area of said second led module is greater than the area of said first led module; Therefore; Can the luminous intensity of disperseing at the light that LED sent of intermediate arm work always, making to send on the unit projected area on the intermediate arm be reduced, with the luminous intensity on four brachium pontis of balance.And when changing appearred in each LED on the brachium pontis, because four brachium pontis ratios of Wheatstone bridge are consistent, each brachium pontis parameter was consistent, and the influence of various interference is cancelled out each other easily, thereby also reduces the systematic error in the AC LED device.

Before carrying out solid brilliant technology; Owing to directly just realized the series connection of micromeritics between each LED in each said first led module and said second led module in wafer scale through interconnect metal 630; Therefore, when adopting the COB encapsulation technology, simplified the solid crystalline substance of crystal grain, bonding quantity and reduced packaging cost; And in unit are, formed the integrated of many micromeritics, avoided the consistency problem that brings like wavelength, voltage, brightness span in the stepping between wafer (BIN); Simultaneously, when the AC LED device that subsequent technique is prepared was worked under the low current high voltage, current density local congestion effect was resolved.

More excellent, on the said Wheatstone bridge AC LED device that forms, apply fluorescent powder silica gel 644, to prepare the AC LED device (referring to Fig. 6 g) that can adapt to the different colours demand.

Referring to Fig. 6 d; The invention allows for a kind of Wheatstone bridge AC LED device, comprise four first led modules 632 and one second led module 634, said first led module 632 is as brachium pontis; Said second led module 634 is as intermediate arm; Each first led module 632 comprises at least two LED respectively with each second led module 634, and wherein, the area of said second led module 634 is greater than the area of said first led module 632.

To achieve these goals, corresponding, a kind of manufacturing approach with substrate of series LED also is provided, said method comprises the steps:

S200 a: substrate is provided, on said substrate, forms N type limiting layer, epitaxial loayer and P type contact electrode layer from the bottom to top successively.

Referring to Fig. 8 a, on substrate 700, deposit earlier N type limiting layer 704, epitaxial loayer 711 and P type contact electrode layer 712 from bottom to top successively.

Said epitaxial loayer 711 comprises multiple quantum well active layer 706, the P type limiting layer 710 that is formed at successively on the said N type limiting layer 704.

More excellent, before forming N type limiting layer 704 on the said substrate 700, on said substrate 700, form nitride resilient coating 702.

More excellent, when forming said epitaxial loayer 711, also be included in and form before the P type limiting layer 710, on said multiple quantum well active layer 706, form P type nitride layer 708.

Wherein, said P type limiting layer 710 can be a P type nitride, and the material that said P type contact electrode layer 712 uses is tin indium oxide (ITO).

S201: make at least nine isolated grooves that run through P type contact electrode layer, epitaxial loayer, N type limiting layer, above substrate, to isolate at least ten zones, the corresponding LED in each zone.

Referring to Fig. 8 b; Deposition photoresist layer (not shown) carries out photoresist layer graphically with general photoetching process on P type contact electrode layer 712, is mask with patterned photoresist layer then; Adopt inductively coupled plasma (Inductively Coupled Plasma; ICP) etching technics prepares at least nine isolated grooves 714 on substrate 700, and said isolated groove 714 runs through P type contact electrode layer 712, epitaxial loayer 711 and N type limiting layer 704, exposes the surface of substrate 700; And the part on the substrate 700 is divided at least ten zones, so that subsequent technique prepares a LED in each zone.At last, remove photoresist layer.

If after forming said substrate 700; On substrate 700, deposited nitride resilient coating 702; When then on substrate 700, preparing isolated groove 714; Said isolated groove 714 runs through after P type contact electrode layer 712, epitaxial loayer 711, the N type limiting layer 704, also need continue etching nitride resilient coating 702.

S202: in each said zone, make a N type contact electrode step that is connected with isolated groove, said N type contact electrode step runs through P type contact electrode layer, epitaxial loayer.

Referring to Fig. 8 c; Deposition photoresist layer (not shown) on P type contact electrode layer 712 and the substrate surface that exposes; With general photoetching process photoresist layer is carried out graphically, and be mask, in each said zone, adopt ICP etching technics etching P type contact electrode layer 712 and epitaxial loayer 711 with patterned photoresist layer; Said etching stopping is on N type limiting layer 704, to form the N type contact electrode step 716 that is connected with isolated groove 714.At last, remove photoresist layer.

Certainly, said etching also can stop in the N type limiting layer 704 and (promptly etch away the N type limiting layer 704 of segment thickness, the situation shown in Fig. 8 c), to form the N type contact electrode step 716 that is connected with isolated groove 714, can realize the object of the invention equally.

S203: at the surface of P type contact electrode layer, N type contact electrode step and the inner surface deposit dielectric layer of isolated groove.

Referring to Fig. 8 d, at deposit dielectric layer 718 on P type contact electrode layer 712 surface and on the inner surface of said N type contact electrode step 716 and isolated groove 714.

S204: remove the part spacer medium layer that is close to each isolated groove through photoetching, etching technics; Expose part P type contact electrode layer and part N type limiting layer respectively; Plated metal in part P type contact electrode layer, part N type limiting layer and the isolated groove that is exposed and on the isolated groove surface; N electrode, the P electrode and being used to of producing once out is connected the interconnect metal of the electrode of adjacent LED, forms to have the substrate of series LED successively.

At first; Referring to Fig. 8 e, deposition photoresist layer (not shown) on the spacer medium layer 718 of said structure, then; Mask 720 is set above the said structure that has deposited said photoresist layer; Mask 720 is through ultraviolet light illumination, and the back of developing is transferred to figure 722 on the photoresist layer, forms patterned photoresist layer.

Then; Referring to Fig. 8 f; With patterned photoresist layer is mask; Adopt general etching technics to remove the part spacer medium layer 718 that is close to each isolated groove 714, expose part P type contact electrode layer 712 respectively with making P type electrode in subsequent step, and part N type limiting layer 704 is to make N type electrode in subsequent step.

At last; Referring to Fig. 8 g; Plated metal on the above-mentioned part P type contact electrode layer 712 that exposes, part N type limiting layer 704 and in the isolated groove 714 and isolated groove 714 surfaces; Produce once out P electrode 726, N electrode 728 and be used to be connected the interconnect metal 730 of two adjacent LEDs form and have the substrate of series LED successively.Wherein, the material of making P electrode 726, N electrode 728 and interconnect metal 730 can be chromium gold (Cr/Au) alloy or nickel gold (Ni/Au) alloy or other metals.

Owing to once expose the zone of required plated metal; And in said area exposed, adopt the same conductive plated metal to form each electrode and the interconnect metal that realizes that each LED is connected of each LED synchronously; Therefore needn't be respectively the zone of the required plated metal that exposes be cleaned repeatedly; The metal waste of also having avoided gradation to carry out Metal Deposition and having caused; Therefore, not only saved technology costs such as Metal Deposition and cleaning procedure, and easy AC LED element manufacturing step; Simultaneously, the electrode of each LED and interconnect metal are deposition simultaneously, have avoided the high-aspect-ratio deposition of interconnect metal, therefore possess good step coverage, have improved the interconnected reliability between each LED in the AC LED device of subsequent technique preparation.

Though the present invention with preferred embodiment openly as above; But it is not to be used for limiting claim; Any those skilled in the art are not breaking away from the spirit and scope of the present invention; Can make possible change and modification, so protection scope of the present invention should be as the criterion with the scope that claim of the present invention was defined.

Claims

1. the manufacturing approach of a Wheatstone bridge AC LED device comprises the steps:

The substrate of LED with series connection is provided;

Said substrate is cut; Obtain a plurality of first led modules and second led module; Wherein, Each first led module comprises two LED at least with each second led module, and the quantity ratio of said first led module and second led module was smaller or equal to 4: 1, and the area of said second led module is greater than the area of said first led module;

Said first led module is packaged into Wheatstone bridge AC LED device as brachium pontis and said second led module as intermediate arm.

2. according to the manufacturing approach of the said Wheatstone bridge AC LED of claim 1 device; It is characterized in that; Also comprise: before said substrate is cut, the LED of said series connection is tested, and optionally the substrate of the LED of said series connection is carried out laser scribing according to test result.

3. according to the manufacturing approach of the said Wheatstone bridge AC LED of claim 1 device, it is characterized in that, form the substrate of the LED with series connection through following processing step:

One substrate is provided, on said substrate, forms N type limiting layer, epitaxial loayer and P type contact electrode layer from the bottom to top successively;

Make at least nine isolated grooves that run through P type contact electrode layer, epitaxial loayer, N type limiting layer, above substrate, to isolate at least ten zones, the corresponding LED in each zone;

In each said zone, make a N type contact electrode step that is connected with isolated groove, said N type contact electrode step runs through P type contact electrode layer, epitaxial loayer;

At the surface of P type contact electrode layer, N type contact electrode step and the inner surface deposit dielectric layer of isolated groove;

Remove the part spacer medium layer that is close to each isolated groove through photoetching, etching technics; Expose part P type contact electrode layer and part N type limiting layer respectively; Plated metal in part P type contact electrode layer, part N type limiting layer and the isolated groove that is exposed and on the isolated groove surface; N electrode, the P electrode and being used to of producing once out is connected the interconnect metal of the electrode of adjacent LED, forms the substrate with series LED.

4. according to the manufacturing approach of the said Wheatstone bridge AC LED of claim 3 device, it is characterized in that: after forming the processing step of substrate of the LED with series connection, also comprise: the said substrate of attenuate.

5. according to the manufacturing approach of the said Wheatstone bridge AC LED of claim 3 device, it is characterized in that: before forming N type limiting layer on the said substrate, also comprise: on said substrate, form the nitride resilient coating.

6. according to the manufacturing approach of the said Wheatstone bridge AC LED of claim 3 device, it is characterized in that: said epitaxial loayer comprises multiple quantum well active layer and is formed at the P type limiting layer on the multiple quantum well active layer.

7. according to the manufacturing approach of the said Wheatstone bridge AC LED of claim 6 device, it is characterized in that: on said N type limiting layer, form in the step of said epitaxial loayer, before forming P type limiting layer, also comprise: deposition P type nitride layer.

8. the manufacturing approach of Wheatstone bridge AC LED device according to claim 3 is characterized in that: said N type contact electrode platform runs through P type contact electrode layer, epitaxial loayer and extends in the part N type limiting layer.

9. according to the manufacturing approach of the said Wheatstone bridge AC LED of claim 3 device, it is characterized in that: said N electrode, P electrode are identical with the employed electric conducting material of interconnect metal.

10. according to the manufacturing approach of the said Wheatstone bridge AC LED of claim 9 device, it is characterized in that: the material of said N electrode, P electrode and interconnect metal is the nickel billon, or the chromium billon.

11. the manufacturing approach according to each said Wheatstone bridge AC LED device in the claim 1 to 10 is characterized in that: wafer is directly adorned said first led module and second led module is encapsulated on the employing plate.

12. the manufacturing approach according to the AC LED of Wheatstone bridge described in the claim 11 device is characterized in that: form after the Wheatstone bridge AC LED device, also comprise: on said Wheatstone bridge AC LED device, apply fluorescent powder silica gel.

13. a Wheatstone bridge AC LED device that makes according to the manufacturing approach of each described Wheatstone bridge AC LED device in the claim 1 to 12 is characterized in that, comprising:

Four first led modules and one second led module; Said first led module is as brachium pontis; Said second led module is as intermediate arm; Each first led module comprises at least two LED respectively with each second led module, and wherein, the area of said second led module is greater than the area of said first led module.