Method of applying a protective coating to a touch screen panel

• US 6,406,758 B1
• Filed: 07/25/2000
• Issued: 06/18/2002
• Est. Priority Date: 07/25/2000
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Bottari, Frank J., Richter, Paul J., Li, Chia-Yen
• Primary Examiner(s): BARR, MICHAEL E
• Application Number:
  US09/626,272
• Time in Patent Office: 693 Days
• Field of Search: 427/512, 427/515, 427/557, 427/559, 427/162, 427/58, 427/240, 427/397.7, 427/376.2, 427/387, 427/420, 427/421, 427/428, 427/430.1
• US Class Current: 427/557
• CPC Class Codes: C09D 183/04 Polysiloxanes
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means

Abstract

A method of applying a protective coating to a touch screen panel. A coating material which cures at an elevated temperature is applied to a touch screen panel on at least one surface thereof. The panel is then heated to a temperature which does not adversely affect the panel by irradiating the panel imparting energy to the coating material to more fully cure the coating material in a shorter time period without damaging the panel.

Claims

1. A method of applying a protective coating to a touch screen panel, the method comprising:

applying to a touch screen panel on at least one surface thereof a coating material which cures at a temperature above 500°

C.; and

heating the panel to a temperature which does not cause thermal damage to the panel by irradiating the panel with infrared energy having wavelength of between 2.5-6.0 microns and imparting energy to the coating material to more ally cure the coating material in a shorter time period than in the absence of irradiation and without damaging the panel.

2. The method of claim 1 in which the coating material is a silicate polymer solution.

3. The method of claim 2 in which the silicate polymer solution is a silicate solution synthesized from the hydrolysis and condensation of silicon alkoxides.

4. The method of claim 3 in which the silicate polymer solution includes sodium acetate, water, tetraethoxysilane, methyltriethoxysilane, isopropanol, and ethanol.

5. The method of claim 1 in which the step of applying the coating material is performed by the class of methods selected from the group consisting of spin coating, dip coating, spray coating, meniscus coating, flow coating, screen printing, and roll coating.

6. The method of claim 1 in which irradiating is accomplished by an infrared radiation source.

7. The method of claim 6 in which the infrared radiation source is an array of externally wound quartz heater tubes.

8. The method of claim 6 in which the infrared radiation source emits radiation at wavelengths in the range of between 2.5 and 6.0 microns.

9. The method of claim 1 in which heating includes both irradiation and convective heating at the same time and in the same oven.

10. The method of claim 1 in which heating takes place in an oven equipped with infrared heaters disposed over a conveyor which transports the coated touch screen panels.

11. The method of claim 10 in which the oven is equipped with externally wound quartz heater tubes for irradiating the touch screen panels with infrared radiation and further equipped with refractory heaters for convectively heating the touch screen panels.

12. A method of applying a protective coating to a touch screen panel, the method comprising:

applying to a touch screen panel on at least one surface thereof a coating material which cures at an elevated temperature;

heating the panel to a temperature which does not cause thermal damage to the panel by irradiating the panel and imparting energy to the coating material to more filly cure the coating material in a shorter time period than in the absence of irradiation and without damaging the panel; and

wherein said heating takes place in an oven equipped with infrared heaters disposed over a conveyor which transports the coated touch screen panels, and wherein said oven is further equipped with refractory heaters for convectively heating the touch screen panels.

13. A method of applying a protective coating to a touch screen panel, the method comprising:

applying to a touch screen panel on at least one surface thereof an abrasion resistant coating material which cures at an elevated temperature; and

heating the panel to a temperature which does not cause thermal damage to the panel by irradiating the panel with infrared radiation to impart energy to the coating material to more fully cure the coating material in 1-2 minutes than without infrared radiation and without damaging the panel.

14. A method of applying an abrasion resistant protective coating to a touch screen panel, the method comprising:

applying to a glass substrate a resistive layer and, on a periphery of the resistive layer, an edge electrode pattern;

applying over the resistive layer an abrasion resistant protective coating material including a silicate polymer solution which densities at a temperature of above about 500°

C.; and

irradiating the panel with infrared radiation having a wavelength of between 2.5 and 6.0 microns to heat the panel to a temperature which does not cause thermal damage to the panel and yet imparting energy to the protective coating material to more fully cure and densify the protective coating material in a shorter time period than in the absence of radiation and without damaging the panel.