Absorptive color conversion film

• US 10,333,036 B2
• Filed: 06/01/2018
• Issued: 06/25/2019
• Est. Priority Date: 06/23/2016
• Status: Active Grant

• Current Assignee: Elux Inc.
• Original Assignee: Elux Inc.
• Inventors: Ulmer, Kurt
• Primary Examiner(s): Yechuri, Sitaramarao S
• Application Number:
  US15/995,486
• Publication Number:
  US 20180366622A1
• Time in Patent Office: 389 Days
• CPC Class Codes: B41J 2/2103 Features not dealing with the colouring process per se, e.g. construction of printers or heads, driving circuit adaptations
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 2933/005 relating to encapsulations
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• 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 33/54 having a particular shape
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• 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

A method is provided for fabricating an emissive display color conversion film. An emissive substrate top surface is conformally coated with an optically transparent carrier film, covering an array of emissive elements. A suspension, including a fluid and a color conversion material (e.g., QDs), is then selectively deposited in absorption regions overlying the emissive elements, for example, using inkjet patterning. After the suspension is absorbed into the absorption regions, the fluid is removed from the suspension, leaving the color conversion material in the absorption regions, and forming the color conversion film. The removal of the fluid encapsulates the color conversion material in the absorption regions. Typically, the conformal coating is thick enough to form a planar top surface. The conformally coating of carrier film may also act to encapsulate both properly aligned emissive elements, as well as misaligned emissive elements that may be located on the emissive substrate top surface.

Claims

1. An emissive display color conversion film comprising:

an emissive substrate comprising a top surface populated with an array of emissive elements;

a color conversion layer comprising;

a transparent carrier film with a top surface, conformally coating the emissive substrate top surface with a first thickness;

a plurality of absorption regions formed in the carrier film top surface and having a second thickness less than the first thickness, each absorption region overlying a corresponding emissive element and separated from adjacent absorptive regions by the transparent carrier film; and

,

a color conversion material occupying only the absorption regions of the color conversion layer.

2. The emissive display color conversion film of claim 1 wherein the color conversion layer has a planar top surface.

3. The emissive display color conversion film of claim 1 wherein the color conversion material comprises quantum dots (QDs).

4. The emissive display color conversion film of claim 1 wherein the emissive elements are capable of emitting a first wavelength of light;

and,

wherein absorption regions are capable of emitting a second wavelength of light, different than the first wavelength.

5. The emissive display color conversion film of claim 1 wherein the array of emissive elements, capable of emitting a first wavelength of light, is organized into a plurality of pixels, each pixel comprising:

a first absorption region with a corresponding first color conversion material capable of emitting light at a second wavelength of light, different than the first wavelength of light; and

,

a second absorption region with a corresponding second color conversion material capable of emitting light at a third wavelength of light, different from the first and second wavelengths of light.

6. The emissive display color conversion film of claim 1 wherein the carrier film is an optically transparent polymer.

7. The emissive display color conversion film of claim 6 wherein the carrier film has an affinity for the absorption of a fluid selected from the group consisting of water, alcohol, hydrocarbons, and organic monomers.

8. The emissive display color conversion film of claim 6 wherein the polymer is selected from the group consisting of polyolefins, with the polyolefins selected from the group consisting of polyethylene and polypropylene, and linear low-density polyethylene (LLDPE).

9. The emissive display color conversion film of claim 1 wherein the emissive substrate comprises a plurality of wells formed in the emissive substrate top surface, each well having a bottom surface with two electrical interfaces formed on the bottom surface;

and,

wherein the emissive elements are inorganic light emitting diodes (LEDs) having a top surface, each LED having two electrical contacts formed on the LED top surface, with each electrical contact connected to a corresponding electrical interface of a corresponding well.

10. The emissive display color conversion film of claim 1 wherein the emissive substrate comprises a plurality of wells formed in the emissive substrate top surface, each well having a bottom surface with a single electrical interface formed on the bottom surface;

wherein the emissive elements are inorganic LEDs having a top surface, each LED having a single electrical contact formed on the LED top surface, connected to a corresponding electrical interface of a corresponding well, and an electrical contact formed an LED bottom surface; and

,

the emissive display color conversion film further comprising;

an electrical interface formed on the substrate top surface connected to the electrical contact on the LED bottom surface.

11. The emissive display color conversion film of claim 1 wherein the emissive substrate comprises a first plurality of wells formed in the emissive substrate top surface;

wherein the emissive elements have a third thickness, with a first plurality of emissive elements populating the wells and a second plurality of misaligned emissive elements residing on the emissive substrate top surface adjacent to the wells; and

,

wherein the color conversion layer first thickness, greater than the third thickness, encapsulates the misaligned emissive elements.

12. The emissive display color conversion film of claim 1 wherein the array of emissive elements, capable of emitting a first wavelength of light, is organized into a plurality of pixels, each pixel comprising:

a first absorption region with a corresponding first color conversion material capable of emitting light at a second wavelength of light, different than the first wavelength of light;

a second absorption region with a corresponding second color conversion material capable of emitting light at a third wavelength of light, different from the first and second wavelengths of light; and

,

a third absorption region with a corresponding third color conversion material capable of emitting light at a fourth wavelength of light, different from the first, second, and third wavelengths of light.

13. The emissive display color conversion film of claim 1 further comprising:

a polymerized monomer layer in the absorption region.

14. A method for fabricating an emissive display color conversion film, the method comprising:

providing an emissive substrate comprising a top surface populated by an array of emissive elements;

conformally coating the emissive substrate top surface with an optically transparent carrier film having a top surface and a first thickness, covering the emissive elements;

selectively depositing a suspension, including a fluid and a color conversion material, over the transparent carrier film forming a plurality of absorption regions, each absorptive region overlying a corresponding emissive element and separated from adjacent absorptive regions by the transparent carrier film;

absorbing the suspension into the absorption regions;

modifying the suspension, leaving the color conversion material in only the absorption regions and forming absorptive regions in the transparent carrier film top surface having a second thickness, less than the first thickness; and

,

forming the color conversion film.

15. The method of claim 14 wherein modifying the suspension includes encapsulating the color conversion material in the absorption regions.

16. The method of claim 14 wherein selectively depositing the suspension includes inkjet patterning the suspension.

17. The method of claim 14 wherein conformally coating the emissive substrate top surface with the optically transparent carrier film includes depositing the optically transparent carrier film with sufficient thickness to form a planar top surface.

18. The method of claim 14 wherein conformally coating the emissive substrate top surface with the optically transparent carrier film includes encapsulating the emissive elements.

19. The method of claim 14 wherein selectively depositing the suspension includes the color conversion material comprising quantum dots (QDs).

20. The method of claim 14 wherein providing the array of emissive elements includes providing emissive elements capable of emitting a first wavelength of light;

and,

wherein absorbing the suspension in the absorption regions includes forming absorption regions capable of emitting a second wavelength of light, different than the first wavelength.

21. The method of claim 14 wherein providing the array of emissive elements includes providing emissive elements organized into a plurality of pixels, with each pixel comprising at least three emissive elements capable of emitting a first wavelength of light;

wherein selectively depositing the suspension includes;

selectively depositing a first suspension including a first color conversion material, capable of emitting a second wavelength of light different than the first wavelength of light, overlying a first absorption region of each pixel; and

,

selectively depositing a second suspension including a second color conversion material, capable of emitting a third wavelength of light different from the first and second wavelengths of light, overlying a second absorption region of each pixel.

22. The method of claim 14 wherein conformally coating the emissive substrate top surface with the optically transparent carrier film includes conformally coating the emissive substrate with an optically transparent polymer.

23. The method of claim 22 wherein selectively depositing the suspension including the fluid includes selectively depositing a fluid selected from the group consisting of a hydrocarbon, organic monomer, alcohol, and water.

24. The method of claim 22 wherein conformally coating the emissive substrate with the optically transparent polymer includes the polymer being selected from the group consisting of polyolefins, with the polyolefins selected from the group consisting of polyethylene and polypropylene, and linear low-density polyethylene (LLDPE).

25. The method of claim 14 wherein providing the emissive substrate includes:

providing an emissive substrate with a plurality of wells formed in the emissive substrate top surface, each well having a bottom surface with two electrical interfaces formed on the bottom surface; and

,

providing inorganic light emitting diode (LED) emissive elements having a top surface, each LED having two electrical contacts formed on the LED top surface, with each electrical contact connected to a corresponding electrical interface of a corresponding well.

26. The method of claim 14 wherein providing the emissive substrate includes:

providing an emissive substrate with a plurality of wells formed in the emissive substrate top surface, each well having a bottom surface with a single electrical interface formed on the bottom surface;

providing inorganic LED emissive elements having a top surface, each LED having a single electrical contact formed on the LED top surface, connected to a corresponding electrical interface of a corresponding well, and an electrical contact formed on an LED bottom surface; and

,

the method further comprising;

prior to depositing the carrier film, forming an electrical interface on the substrate top surface connected to the electrical contact on the LED bottom surface.

27. The method of claim 14 wherein providing the emissive substrate includes:

providing an emissive substrate with a plurality of wells formed in the emissive substrate top surface; and

,

depositing the emissive elements in the wells using a solution flow deposition process.

28. The method of claim 14 wherein providing the emissive substrate includes:

providing an emissive substrate with a first plurality of wells formed in the emissive substrate top surface;

providing emissive elements having a third thickness;

providing a first plurality of emissive elements populating the wells;

providing a second plurality of misaligned emissive elements residing on the emissive substrate top surface adjacent to the wells;

wherein conformally coating the emissive substrate top surface with the optically transparent carrier film includes conformally coating the emissive substrate top surface with the optically transparent carrier film first thickness, greater than the third thickness; and

,

the method further comprising;

encapsulating the misaligned emissive elements with the optically transparent carrier film.

29. The method of claim 14 wherein providing the array of emissive elements includes providing emissive elements organized into a plurality of pixels, with each pixel comprising at least three emissive elements capable of emitting a first wavelength of light;

wherein selectively depositing the suspension includes;

selectively depositing a first suspension including a first color conversion material, capable of emitting a second wavelength of light different than the first wavelength of light, overlying a first absorption region of each pixel;

selectively depositing a second suspension including a second color conversion material, capable of emitting a third wavelength of light different from the first and second wavelengths of light, overlying a second absorption region of each pixel; and

,

selectively depositing a third suspension including a third color conversion material, capable of emitting a fourth wavelength of light different from the first, second, and third wavelengths of light, overlying a third absorption region of each pixel.

30. The method of claim 14 wherein selectively depositing the suspension including the fluid includes selectively depositing a monomer fluid;

and,

wherein removing the fluid from the suspension includes polymerizing the monomer fluid to form a polymer layer in the absorptive region.