Liquid crystal control circuit, electronic timepiece, and liquid crystal control method

Patent metadata

Field	Value
Publication number	US-10692451-B2
Application number	US-201916356947-A
Country	US
Kind code	B2
Filing date	Mar 18, 2019
Priority date	Mar 22, 2018
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

A liquid crystal controller is provided for a liquid crystal panel having a plurality of pixels, each of which includes a memory element and a display element. The memory element is configured to hold electric potential depending on an image signal and is configured to change the held electric potential based on activation of an enable signal. The display element is configured to be applied voltage depending on the electric potential which the memory element holds. The liquid crystal controller is configured to: hold off outputting the enable signal, for a period th before polarity of AC voltage applied to the display element is inverted and a period (tr+ts) after the polarity of the AC voltage is inverted; and hold off inversion of the polarity of the AC voltage, for an output period of the enable signal and the period th after the output period.

First claim

The invention claimed is:

1. A liquid crystal control circuit for driving a liquid crystal panel, wherein
the liquid crystal panel has a plurality of pixels, each of which including a memory element and a display element,
the memory element is configured to hold electric potential depending on an image signal and is configured to change the held electric potential based on activation of an enable signal,
the display element is configured to be applied voltage depending on the electric potential which the memory element holds, and
the liquid crystal control circuit is configured to:
hold off outputting the enable signal, for a predetermined first period before polarity of AC voltage applied to the display element is inverted and a predetermined second period after the polarity of the AC voltage is inverted; and
hold off inversion of the polarity of the AC voltage, for an output period of the enable signal and the predetermined first period after the output period.

2. The liquid crystal control circuit according to claim 1 , wherein the polarity of the AC voltage applied to the display element is inverted at a predetermined interval, while the inversion is not held off based on outputting of the enable signal.

3. An electronic timepiece comprising:
the liquid crystal control circuit according to claim 2 ; and
the liquid crystal panel.

4. An electronic timepiece comprising:
the liquid crystal control circuit according to claim 1 ; and
the liquid crystal panel.

5. A liquid crystal control circuit for driving a liquid crystal panel, wherein
the liquid crystal panel has a plurality of pixels, each of which including a memory element and a display element,
the memory element is configured to hold electric potential depending on an image signal,
the display element is configured to be applied voltage depending on the electric potential which the memory element holds, and
the liquid crystal control circuit comprises:
a counter configured to output an inversion request signal for requesting inversion of polarity of AC voltage applied to the display element, at a predetermined interval;
a polarity inversion unit configured to invert the polarity of the AC voltage in response to the inversion request signal;
an enable signal output unit configured to output an enable signal to activate the image signal which is output to the liquid crystal panel; and
an exclusive output controller configured to determine whether to output the inversion request signal to the polarity inversion unit or to output the output request signal to the enable signal output unit.

6. The liquid crystal control circuit according to claim 5 , wherein the polarity inversion unit is configured to invert the polarity of the AC voltage when a predetermined first period elapses after reception of the inversion request signal.

7. An electronic timepiece comprising:
the liquid crystal control circuit according to claim 6 ; and
the liquid crystal panel.

8. An electronic timepiece comprising:
the liquid crystal control circuit according to claim 5 ; and
the liquid crystal panel.

9. A liquid crystal control method for driving a liquid crystal panel, wherein
the liquid crystal panel has a plurality of pixels, each of which including a memory element and a display element,
the memory element is configured to hold electric potential depending on an image signal and is configured to change the held electric potential based on activation of an enable signal,
the display element is configured to be applied voltage depending on the electric potential which the memory element holds, and
the liquid crystal control method comprises:
holding off outputting the enable signal, for a predetermined first period before polarity of AC voltage applied to the display element is inverted and a predetermined second period after the polarity of the AC voltage is inverted; and
holding off inversion of the polarity of the AC voltage, for an output period of the enable signal and the predetermined first period after the output period.

Assignees

• Casio Computer Co Ltd

Inventors

• Ono Takahiro
• Ochiai Fumiaki

Classifications

• G04G9/04

  by controlling light sources, e.g. electroluminescent diodes {(G04G9/0058 takes precedence)} · CPC title

• G09G3/3614 Primary

  Control of polarity reversal in general · CPC title

• G09G2330/021

  Power management, e.g. power saving · CPC title

• G09G2310/08

  Details of timing specific for flat panels, other than clock recovery · CPC title

• G09G3/36

  using liquid crystals · CPC title