LED production method and LEDs

• US 9,859,476 B2
• Filed: 07/25/2014
• Issued: 01/02/2018
• Est. Priority Date: 07/10/2014
• Status: Active Grant

• Current Assignee: Mtek-smart Corporation
• Original Assignee: Mtek-smart Corporation
• Inventors: Matsunaga, Masafumi
• Primary Examiner(s): Bachner, Robert
• Assistant Examiner(s): REIDA, MOLLY KAY
• Application Number:
  US15/324,826
• Publication Number:
  US 20170207371A1
• Time in Patent Office: 1,257 Days
• Field of Search: 438 26- 28, 438 29, 257 98-100
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 2933/0058 relating to optical field-shaping elements
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/005 Processes
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

Provided is an LED production method that can produce a great number of high-quality LEDs at low production cost. A binder-rich layer is formed on LEDs to increase the adhesiveness between the LEDs and a substrate; a phosphor layer or phosphor-rich layer is formed over the layer with a mask put on the layer; and the phosphor or a mixture of the phosphor and binder on the mask is recovered and reused.

Claims

1. A method for producing LEDs, the LEDs being LEDs obtained by coating LED chips on an LED substrate with a phosphor, the method comprising:

a first step of forming a mask having openings and adhered to the LED substrate for filling a binder-rich first slurry containing at least a phosphor and a binder to at least peripheries of the LED chips;

a second step of filling the first slurry to at least the peripheries of the LED chips in such a manner that a level of the filled first slurry falls within a range of ±

30 micrometers from heights of the LED chips; and

a third step of filling or applying a phosphor-rich second slurry containing at least a phosphor and a binder onto at least the LED chips.

2. The method for producing LEDs of claim 1, wherein

the LEDs are lead frame LEDs where reflectors serving the mask is formed on the peripheries of the LED chips, and

the second slurry further comprises a solvent.

3. The method for producing LEDs of claim 1, wherein

the LEDs are chip-on-board (COB) LEDs, the method further comprising

a fourth step of facilitating curing of the binder of the first slurry.

4. The method for producing LEDs of claim 1, wherein the second slurry contains at least a solvent and is filled or applied in divided amounts a plurality of times.

5. The method for producing LEDs of claim 4, wherein

after the second step or each time the first slurry is filled in the second step, or each time the second slurry is filled or applied in the third step, curing of the binder is facilitated.

6. The method for producing LEDs of claim 2, wherein a level of the first slurry filled in the second step and then dried is approximately equal to heights of the LED chips.

7. The method for producing LEDs of claim 1, wherein

the second slurry has a plurality of particles,

each particles has one or more phosphors selected from red phosphor, yellow phosphor, green phosphor, and blue phosphor, and

the plurality of particles are filled or applied using different coaters so as to form a plurality of layers.

8. LEDs obtained by a manufactured method comprising:

a first step of causing a first mask having openings corresponding to LED chips on an LED substrate to adhere to the LED substrate;

a second step of filling a binder-rich first slurry containing at least a phosphor and a binder to at least peripheries of the LED chips in such a manner that a level of the filled first slurry falls within a range of ±

30 micrometers from heights of the LED chips; and

a third step of filling or applying a phosphor-rich second slurry containing at least a phosphor, a binder, and a solvent to at least the LED chips a plurality of times.

9. The LEDs obtained by a manufactured method of claim 8, wherein

the LEDs are lead-frame LEDs,

the manufactured method further comprises a fourth step of covering reflectors with a three-dimensional mask so that the reflectors are prevented from being contaminated by the second slurry filled or applied by spraying, and

the third step is performed by spraying.

10. LEDs that are chip-on-board (COB) LEDs, obtained by a manufactured method comprising:

a first step of filling a binder-rich first slurry containing at least a phosphor and a binder to at least peripheries of LED chips in such a manner that a level of the filled first slurry falls within a range of ±

30 micrometers from heights of the LED chips;

a second step of facilitating curing of the binder of the first slurry; and

a third step of filling or applying a phosphor-rich second slurry containing at least a phosphor, a binder, and a solvent to at least the LED chips.