Optical device fabrication

• US 10,571,771 B2
• Filed: 09/28/2018
• Issued: 02/25/2020
• Est. Priority Date: 09/30/2011
• Status: Active Grant

• Current Assignee: View Incorporated
• Original Assignee: View Incorporated
• Inventors: Bhatnagar, Yashraj, Rozbicki, Robert T., Mulpuri, Rao
• Primary Examiner(s): Talbot, Brian K
• Application Number:
  US16/147,291
• Publication Number:
  US 20190033678A1
• Time in Patent Office: 515 Days
• Field of Search: 427 58
• CPC Class Codes: B05D 3/065 After-treatment
• CPC Class Codes: B05D 3/12 by mechanical means
• CPC Class Codes: B05D 5/02 to obtain a matt or rough surface
• CPC Class Codes: B05D 5/12 to obtain a coating with specific electrical properties
• CPC Class Codes: C03B 27/00 Tempering or quenching glass products
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 17/3642 the multilayer coating containing a metal layer
• CPC Class Codes: C03C 2217/94 Transparent conductive oxide layers [TCO] being part of a multilayer coating
• CPC Class Codes: C03C 2218/31 Pre-treatment
• CPC Class Codes: C23C 16/0254 Physical treatment to alter the texture of the surface, e.g. scratching or polishing
• CPC Class Codes: G02F 1/1533 structural features not otherwise provided for
• CPC Class Codes: G02F 1/155 Electrodes
• CPC Class Codes: Y02P 40/57 Improving the yield, e-g- reduction of reject rates

Abstract

Transparent conductive coatings are polished using particle slurries in combination with mechanical shearing force, such as a polishing pad. Substrates having transparent conductive coatings that are too rough and/or have too much haze, such that the substrate would not produce a suitable optical device, are polished using methods described herein. The substrate may be tempered prior to, or after, polishing. The polished substrates have low haze and sufficient smoothness to make high-quality optical devices.

Claims

1. A method comprising:

fabricating an electrochromic window by;

a) polishing a surface of a first transparent conducting layer disposed on a glass substrate; and

then

b) fabricating an all solid state and inorganic electrochromic device on the first transparent conducting layer, wherein;

the electrochromic device comprises an electrochromic layer, a counter electrode layer and a second transparent conducting oxide layer; and

the glass substrate is tempered prior to a).

2. The method of claim 1, wherein polishing reduces haze of the first transparent conducting layer to less than 1%.

3. The method of claim 1, wherein the transparent conducting layer is a tin oxide based material.

4. The method of claim 3, wherein the tin oxide based material comprises fluorinated tin oxide.

5. The method of claim 1, wherein a) includes an abrasive preparation comprising particles having a Mohs hardness scale factor of at least 9.

6. The method of claim 5, wherein the abrasive preparation comprises one or both of alumina and carborundum.

7. The method of claim 5, wherein the abrasive preparation is an alumina slurry having an average particle diameter of 250 nm or greater.

8. The method of claim 7, wherein the average particle diameter is about 1 μ

M.

9. The method of claim 1, wherein a) is performed for between about 10 minutes and about 90 minutes.

10. The method of claim 1, wherein a) is performed until the surface roughness of the transparent conducting layer has an Ra value of between about 1 nm and about 5 nm.

11. The method of claim 1, wherein a) is performed until sheet resistance of the transparent conducting layer is between 5 and 30 Ohms per square.

12. The method of claim 1, wherein sheet resistance of the transparent conducting layer is periodically measured during a).

13. The method of claim 1, wherein:

the electrochromic layer includes tungsten oxide;

the counter electrode layer includes nickel tungsten oxide; and

the second transparent conducting layer includes tin-oxide.

14. The method of claim 1, wherein:

the electrochromic layer includes tungsten oxide or doped tungsten oxide;

the counter electrode layer includes nickel oxide or nickel tungsten oxide, each optionally doped;

and

fabricating the electrochromic device includes;

depositing the electrochromic layer in one or more portions on the polished surface;

depositing the counter electrode layer on the electrochromic layer to form a device stack, wherein one or both of the electrochromic layer and the counter electrode layer includes a layer region comprising a greater than stoichiometric amount of oxygen, the layer region being located at the interface of the electrochromic layer and the counter electrode layer; and

heating the device stack to convert the layer region to an ion conducting and electrically insulating region between the electrochromic and counter electrode layers.

15. The method of claim 14, further comprising applying lithium to the counter electrode layer prior to heating the device stack.

16. The method of claim 14, wherein heating the device stack includes:

heating the device stack in an inert atmosphere, then, heating the device stack in O₂, and, subsequently, heating the device stack in air.

17. The method of claim 14, wherein the ion conducting and electrically insulating region includes one of lithium tungstate, lithium molybdate, lithium niobate, lithium tantalate, lithium titanate, and lithium zirconate.

18. The method of claim 17, wherein the ion conducting and electrically insulating region includes one of tungsten oxide, molybdenum oxide, niobium oxide, titanium oxide, tantalum oxide, zirconium oxide, and cerium oxide.