Liquid crystal display panel for using in a timepiece comprising reflective polarizers and absorption film

• US 6,351,297 B1
• Filed: 02/25/1999
• Issued: 02/26/2002
• Est. Priority Date: 06/30/1997
• Status: Expired due to Fees

• Current Assignee: Citizen Holdings Co., Ltd. (Citizen Electronics Company Limited)
• Original Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Inventors: Akiba, Yuichi, Akiyama, Takashi, Ide, Masafumi, Nakagawa, Koji, Kikuchi, Masami, Toida, Takashi, Sekiguchi, Kanetaka
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Chowdhury, Tarifur R.
• Application Number:
  US09/242,848
• Time in Patent Office: 1,097 Days
• Field of Search: 349/96, 349/97, 349/98, 349/99, 349/112, 349/113
• US Class Current: 349/96
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133545 Dielectric stack polarisers
• CPC Class Codes: G02F 2201/08 light absorbing layer
• CPC Class Codes: G02F 2203/02 reflective
• CPC Class Codes: G04G 9/0035 constructional

Abstract

A timepiece according to the invention is provided with a liquid crystal display panel capable of displaying at least either of time information or calendar information, and the liquid crystal display panel comprises a liquid crystal cell with liquid crystals sealed thereinbetween, sandwiched between two transparent substrates having an electrode on each of inner surfaces thereof facing each other, polarizing sheets disposed on the external surface of the respective substrates, and a light absorption film disposed on the side of one of the polarizing sheets opposite from the liquid crystal cell. For each of the polarizing sheets, a sheet reflecting the light linearly polarized in the direction orthogonal to the transmission axis thereof is used so that either of a background or a display segment is displayed in a metallic color while the other is displayed in the color of the light absorption film. Thus, the invention provides a timepiece (watch or clock) capable of indicating display that is attractively variable in design.

Claims

1. A timepiece comprising a liquid crystal display panel capable of displaying at least either of time information or calender information, said liquid crystal display panel comprising:

a liquid crystal cell with liquid crystals sealed therebetween, sandwiched between two transparent substrates having an electrode on each of inner surfaces thereof facing each other;

polarizing sheets disposed on an external surface of the transparent substrates of the liquid crystal cell, respectively; and

a light absorption film disposed on the side of only one of the polarizing sheets, opposite from the liquid crystal cell, wherein each of said polarizing sheets is a sheet reflecting the light linearly polarized in a direction orthogonal to the transmission axis thereof.

2. A timepiece according to claim 1, wherein the polarizing sheets disposed on the opposite sides of the liquid crystal cell, respectively, are arranged such that the transmission axes of the respective polarizing sheets cross each other at right angles.

3. A timepiece according to claim 1, wherein the polarizing sheets disposed on the opposite sides of the liquid crystal cell, respectively, are arranged such that the transmission axes of the respective polarizing sheets are aligned parallel with each other.

4. A timepiece according to claim 1, wherein liquid crystals causing linearly polarized light passing therethrough to undergo phase modulation or intensity modulation are sealed in the liquid crystal cell.

5. A timepiece according to claim 4, wherein the liquid crystals are twisted nematic liquid crystals.

6. A timepiece according to claim 1, wherein one of the polarizing sheets, disposed on a visible side of the liquid crystal cell, is arranged such that the transmission axis thereof is aligned in the direction of, or in the direction orthogonal to, long axes of liquid crystal molecules present on the visible side of the liquid crystal cell.

7. A timepiece according to claim 1, wherein the liquid crystal display panel is provided with a polarizing film installed on the external side of the polarizing sheet disposed on the visible side of the liquid crystal cell, for absorbing the light linearly polarized in the direction orthogonal to the transmission axis thereof, and

wherein the transmission axis of said polarizing film is oriented substantially in the same direction as the transmission axis of the polarizing sheet disposed on the visible side of the liquid crystal cell.

8. A timepiece according to claim 7, wherein the polarizing film is a color polarizing film capable of mainly absorbing a light component at a specific wavelength, out of the light linearly polarized in the direction orthogonal to the transmission axis thereof.

9. A timepiece according to claim 1, wherein the liquid crystal display panel is provided with a light diffusion layer installed on the external side of the polarizing sheet disposed on the visible side of the liquid crystal cell.

10. A timepiece comprising a liquid crystal display panel capable of displaying at least either of time information or calendar information, said liquid crystal display panel comprising:

a liquid crystal cell with liquid crystals sealed thereinbetween, sandwiched between two transparent substrates having an electrode on each of inner surfaces thereof facing each other;

polarizing sheets disposed on an external surface of the transparent substrates of the liquid crystal cell, respectively; and

a backlight disposed on a side of only one of the polarizing sheets, opposite from the liquid crystal cell, wherein each of said polarizing sheets is a sheet reflecting the light linearly polarized in a direction orthogonal to the transmission axis thereof,

wherein a translucent absorbing film is installed between the backlight and the polarizing sheet adjacent thereto.

11. A timepiece according to claim 10, wherein the liquid crystal display panel is provided with a polarizing film disposed on the external side of the polarizing sheet disposed on the visible side of the liquid crystal cell, for absorbing the light linearly polarized in the direction orthogonal to the transmission axis thereof, and

wherein the transmission axis of said polarizing film is oriented substantially in the same direction as the transmission axis of the polarizing sheet disposed on the visible side of the liquid crystal cell.

12. A timepiece according to claim 11, wherein the polarizing film is a color polarizing film capable of mainly absorbing a light component at a specific wavelength, out of the light linearly polarized in the direction orthogonal to the transmission axis thereof.

13. A timepiece according to claim 10, wherein the liquid crystal display panel is provided with a light diffusion layer installed on the external side of the polarizing sheet disposed on the visible side of the liquid crystal cell.