Method for fabricating an emissive display using laminated printed color conversion phosphor sheets

• US 10,262,978 B2
• Filed: 10/09/2017
• Issued: 04/16/2019
• Est. Priority Date: 06/29/2016
• Status: Active Grant

• Current Assignee: Elux Inc.
• Original Assignee: Elux Inc.
• Inventors: Ulmer, Kurt
• Primary Examiner(s): Wilczewski, Mary A
• Application Number:
  US15/727,662
• Publication Number:
  US 20180047710A1
• Time in Patent Office: 554 Days
• Field of Search: 438 69
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2933/0033 relating to semiconductor body packages
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/483 Containers
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• 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

Abstract

Embodiments are related generally to electronic displays and, more particularly, to emissive displays made with transparent sheets having phosphor dots on the surface for the purpose of color conversion.

Claims

1. A method for fabricating an emissive display, the method comprising:

providing a backplane having a top surface with a first number of light emitting diode (LED) devices formed in an array and configured to emit light in a visible spectrum with a first color;

mixing a phosphor material with a binder to yield a phosphor mixture as follows;

mixing a first phosphor material configured to emit light in the visible spectrum with a second color different than the first color;

mixing a second phosphor material configured to emit light in the visible spectrum with a third color, different than the first and second colors;

inking a pattern plate with the phosphor mixture to yield a phosphor ink pattern as follows;

forming a first pattern with a first plurality of phosphor dots made from the first phosphor material;

forming a second pattern comprising a second plurality of phosphor dots made from the second phosphor material;

transferring the phosphor ink pattern to a transparent substrate top surface to yield a pattern of a second number of phosphor dots as follows;

transferring the first pattern of phosphor dots to a first transparent substrate top surface;

transferring the second pattern of phosphor dots to a second transparent substrate top surface;

aligning the transparent substrate so the pattern of the second number of phosphor dots overlies a subset of the first number of LED devices as follows;

aligning the first transparent substrate over the backplane so the phosphor dots overlie a second plurality of LED devices, less than the first plurality of LED devices;

aligning the second transparent substrate over the first transparent substrate so the phosphor dots overlie a third plurality of LED devices, different than the second plurality of LED devices and less than the first plurality of LED devices; and

,

laminating a bottom surface of the transparent substrate to the backplane top surface as follows;

laminating a bottom surface of the first transparent substrate to the backplane top surface; and

,

laminating a bottom surface of the second transparent substrate to the top surface of the first transparent substrate.

2. The method of claim 1, the method further comprising:

forming a plurality of pixels, wherein each of the plurality of pixels includes;

a first area on the first transparent sheet comprising a phosphor dot with the second color and an adjacent region exposing an underlying LED device; and

,

a second area on the second transparent sheet comprising a phosphor dot having the third color and an adjacent region exposing the first area and adjacent region of the first transparent substrate.

3. The method of claim 1, wherein:

mixing the first phosphor material includes the first phosphor material having a first luminescence and a first light absorption characteristic;

mixing the second phosphor material includes the second phosphor material having a second luminescence and a second light absorption characteristic, different than the first luminescence and first light absorption characteristic;

forming the first pattern includes forming a phosphor dot first diameter responsive to the first luminescence and a thickness responsive to the first light absorption characteristic; and

forming the second pattern includes forming a phosphor dot second diameter, responsive to the second luminescence and different than the phosphor dot first diameter, and a second thickness, responsive to the second light absorption characteristic and different than the first thickness.

4. The method of claim 3, wherein providing the backplane includes the LED devices underlying the phosphor dots on the first transparent sheet having a third diameter, the LED devices underlying the phosphor dots on the second transparent sheet having a fourth diameter, and the LED devices exposed by the first and second transparent sheets having a fifth diameter.

5. The method of claim 1, wherein:

transferring the phosphor ink pattern to the transparent substrate includes the first transparent substrate having a thickness of greater than 10 microns;

laminating the bottom surface of the transparent substrate to the backplane top surface includes;

interposing a transparent adhesive between the transparent substrate bottom surface and backplane top surface having a thickness of greater than 10 microns; and

using a process selected from the group consisting of temperature, pressure, or both temperature and pressure.