Other

Renesas Electronics Corporation

Hitachi, Ltd.

Renesas Technology Corp.

Gorou Sakamaki

Yoshikazu Yokota

Kunihiko Tani

Kazuhisa Higuchi

Kimihiko Sugiyama

Takashi Yoneoka

Katsuhiko Yamamoto

In conventional liquid crystal display controllers, the display is reduced in the stand-by state but the liquid crystal display duty is not changed, i.e., even the common electrodes of the rows that are not producing display are scanned, and the consumption of electric power is not decreased to a sufficient degree in the stand-by state. A liquid crystal display controller includes a drive duty selection register capable of being rewritten by a microprocessor, and a drive bias selection register. When the display is changed from the whole display on a liquid crystal display panel to a partial display on part of the rows only, the preset values of the drive duty selection register and of the drive bias selection register are changed, so that the display is selectively produced on a portion of the liquid crystal display panel at a low voltage with a low-duty drive.

Liquid crystal display controller and liquid crystal display device

In conventional liquid crystal display controllers such as for portable telephone sets, the display is reduced in the stand-by state but the liquid crystal display duty is not changed, i.e., even the common electrodes of the rows that are not producing display are scanned, and the consumption of electric power is not decreased to a sufficient degree in the stand-by state. A liquid crystal display controller () includes a drive duty selection register () capable of being rewritten by a microprocessor (), and a drive bias selection register (). When the display is changed from the whole display on a liquid crystal display panel () to a partial display on part of the rows only, the preset values of the drive duty selection register and of the drive bias selection register are changed, so that the display is selectively produced on a portion of the liquid crystal display panel at a low voltage with a low-duty drive.

In conventional liquid crystal display controllers such as for portable telephone sets, the display is reduced in the stand-by state but the liquid crystal display duty is not changed, i.e., even the common electrodes of the rows that are not producing display are scanned, and the consumption of electric power is not decreased to a sufficient degree in the stand-by state. A liquid crystal display controller ( ) includes a drive duty selection register ( ) capable of being rewritten by a microprocessor ( ), and a drive bias selection register ( ). When the display is changed from the whole display on a liquid crystal display panel ( ) to a partial display on part of the rows only, the preset values of the drive duty selection register and of the drive bias selection register are changed, so that the display is selectively produced on a portion of the liquid crystal display panel at a low voltage with a low-duty drive.

In conventional liquid crystal display controllers such as for portable telephone sets, the display is reduced in the stand-by state but the liquid crystal display duty is not changed, i.e., even the common electrodes of the rows that are not producing display are scanned, and the consumption of electric power is not decreased to a sufficient degree in the stand-by state. A liquid crystal display controller (,) includes a drive duty selection register (,) capable of being rewritten by a microprocessor (,), and a drive bias selection register (,). When the display is changed from the whole display on a liquid crystal display panel (,) to a partial display on part of the rows only, the preset values of the drive duty selection register and of the drive bias selection register are changed, so that the display is selectively produced on a portion of the liquid crystal display panel at a low voltage with a low-duty drive.

CPU writes display character codes corresponding to a liquid crystal display position to display RAM to cause any desired character to be read from character generator ROM and to be displayed. There are provided a scroll display line designation register for designating a desired display line to be scrolled and a scroll dot quantity register for designating the scroll quantity in pixels. A scroll register supplies, to a segment shift register, character data which is delayed by the designated number of dots with respect to the character data on the designated display line and causes the display line to be displayed.

Growing community of inventors

Kodaira, Japan

Gorou Sakamaki