Touch panel

• US 7,586,483 B2
• Filed: 11/30/2005
• Issued: 09/08/2009
• Est. Priority Date: 01/11/2005
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Tanabe, Koji, Fujii, Shoji
• Primary Examiner(s): Dharia; Prabodh M
• Application Number:
  US11/289,618
• Publication Number:
  US 20060152640A1
• Time in Patent Office: 1,378 Days
• Field of Search: 345/1.1, 345/76, 345/87, 345/88, 345/96, 345/102, 345/107, 345/156, 345/173, 345/178, 200/600, 349/12, 349/150, 349/67, 349/96, 349/58, 428/455, 428/408, 428/402, 428/195.1, 428/220, 428/209, 428/419, 428/106
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels

Abstract

A touch panel is equipped with a light-transmissive upper substrate, a light-transmissive lower substrate, a polarizing plate bonded onto a top surface of the upper substrate, and a light-transmissive adhesive layer containing acid acceptors. A lower surface of the upper substrate is formed thereon with an upper conductive layer, and a top surface of the lower substrate is formed thereon with a lower conductive layer facing the upper conductive layer, with a certain air gap provided. The polarizing plate has a polarizer and a triacetylcellulose film bonded onto both surfaces of the polarizer. The adhesive layer bonds at least one of the polarizer with the triacetylcellulose film and the upper substrate with the polarizing plate. This makeup provides the touch panel with favorable visibility and easy operability.

Claims

1. A touch panel comprising:

a light-transmissive upper substrate having an upper conductive layer on a lower surface thereof;

a light-transmissive lower substrate having a lower conductive layer on a top surface thereof, the lower conductive layer facing the upper conductive layer, the upper and lower conductive layers having an air gap therebetween;

a polarizing plate bonded onto a top surface of the upper substrate and including a polarizer and a triacetylcellulose film bonded onto opposite surfaces of the polarizer; and

a light-transmissive adhesive bonding at least one of (1) the polarizer with the triacetylcellulose film and (2) the upper substrate with the polarizing plate, the light-transmissive adhesive including acid acceptors.

2. The touch panel as claimed in claim 1, wherein the acid acceptors are 0.2% to 25% by weight of the adhesive layer.

3. The touch panel as claimed in claim 1, further comprising a retardation plate bonded between a top surface of the upper substrate and the polarizing plate.

4. The touch panel as claimed in claim 1, further comprising a light-transmissive cover sheet bonded onto a top surface of the polarizing plate.

5. The touch panel as claimed in claim 1, wherein the acid acceptors include hydrotalcite or acrylate fiber powder.