Touch panel and electronic apparatus using the same

• US 6,903,729 B2
• Filed: 10/04/2002
• Issued: 06/07/2005
• Est. Priority Date: 10/04/2001
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakanishi, Akira, Yamaue, Nobuhiro, Fujii, Shigeyuki
• Primary Examiner(s): WU, XIAO MIN
• Application Number:
  US10/263,722
• Publication Number:
  US 20030071796A1
• Time in Patent Office: 977 Days
• Field of Search: 349/12, 349/79, 349/80, 349/96, 345/173, 345/174, 345/175, 345/176, 345/177, 345/178, 345/179, 345/104, 345/87, 345/88, 178/18.01, 178/18.1
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133521 Interference filters
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures

Abstract

A touch panel has a first transparent substrate with a first transparent conductive layer, and a second transparent substrate with a second transparent conductive layer. Color of the touch panel has a b* value of 2.0 or smaller with respect to the L*a*b* color specification in accordance with JIS Z 8729. At least one of the first and second transparent substrates is provided with a color adjustment layer providing optical interference. The touch panel may further have a third transparent substrate provided with a color adjustment layer, or a third transparent substrate containing a colorant having color complementary to a color of the transparent conductive layer. The touch panel has a less yellowish appearance, and shows minimal color change of a color display device. When attached on a liquid crystal display device in an electronic apparatus, the electronic apparatus exhibits a high grade color display without a sense of incompatibility.

Claims

1. A touch panel comprising:

a first transparent substrate provided with a first transparent conductive layer; and

a second transparent substrate provided with a second transparent conductive layer, said second transparent conductive layer opposing said first transparent conductive layer with a separation distance there between;

wherein a color of said touch panel has a “

b* value”

of 2.0 or smaller as specified by the L*a*b* color specification in accordance with JIS Z 8729.

2. The touch panel of claim 1, wherein at least one of said first transparent substrate and said second transparent substrate is provided with an optical interference layer for color adjustment.

3. The touch panel of claim 2, wherein said optical interference layer controls a maximum peak spectrum of spectral transmittance of visible light to be 500 nm or shorter wavelength.

4. The touch panel of claim 1, wherein at least one of said first transparent substrate and said second transparent substrate is provided with a color adjustment layer containing a colorant which is complementary to a color of said first and second transparent conductive layers.

5. The touch panel of claim 1, wherein at least one of said first and second transparent substrates contains a colorant which is complementary to a color of said first and second transparent conductive layers.

6. The touch panel of claim 1, further comprising a third transparent substrate provided with a color adjustment layer providing optical interference.

7. The touch panel of claim 6, wherein said third transparent substrate is disposed at least one of beneath a lower surface of said first transparent substrate, between said first transparent conductive layer and said first transparent substrate, between said second transparent conductive layer and said second transparent substrate, and on an upper surface of said second transparent substrate.

8. The touch panel of claim 6, wherein said color adjustment layer controls a peak spectrum of spectral transmittance of visible light to be 500 nm or shorter wavelength.

9. The touch panel of claim 1, further comprising a third transparent substrate containing a colorant which is complementary to a color of said first and second transparent conductive layers.

10. The touch panel of claim 9, wherein said third transparent substrate is disposed at least one of beneath a lower surface of said first transparent substrate, between said first transparent conductive layer and said first transparent substrate, between said second transparent conductive layer and said second transparent substrate, and on an upper surface of said second transparent substrate.

11. The touch panel of claim 1, wherein at least one of said first transparent substrate and said second transparent substrate comprises a resin film or a resin sheet.

12. The touch panel of claim 2, wherein said optical interference layer is formed on at least one surface of said first transparent substrate and said second transparent substrate.

13. The touch panel of claim 12, wherein said optical interference layer controls one of a maximum peak position and a highest value position of a spectral transmittance of visible light to be 500 nm or shorter wavelength.

14. An electronic apparatus comprising:

a liquid crystal display device; and

a touch panel disposed in front of a display surface of said liquid crystal display device, said touch panel comprising;

a first transparent substrate provided with a first transparent conductive layer; and

a second transparent substrate provided with a second transparent conductive layer, said second transparent conductive layer opposing said first transparent conductive layer with a separation distance there between,

wherein a color of said touch panel has a “

b* value”

of 2.0 or smaller as specified by the L*a*b* color specification in accordance with JIS Z 8729, and a sum of the b* value of said touch panel and the b* value of a polarization plate of said liquid crystal display device is 3.0 or smaller.