Hitachi, Ltd.

Other

Renesas Technology Corp.

Renesas Electronics Corporation

Atsuhiro Higa

Yasuyuki Kudo

Tsutomu Furuhashi

Hiroshi Kurihara

Kazunari Kurokawa

Akihito Akai

Takeshi Maeda

Yoshikazu Yokota

Naruhiko Kasai

Kazuo Ookado

Hisayuki Ohhara

Toshimitsu Matsudo

Hiroyuki Nitta

Satoru Tsunekawa

Kazuo Okado

Masashi Nakamura

Hirobumi Koshi

Kenichi Nagashima

The present invention provides a liquid crystal display controller device and method which provides for a full and/or partial display with good display quality and/or low power consumption based on the scanning period for an active scan line being dependent upon a number of reference clock pulses. Some embodiments of the present invention include one or more of the following features: keeping the frequency substantially constant for different numbers of active scan lines, allowing change of the frequency due to characteristics of the LCD, displaying gradation with near linear effective voltage characteristics, displaying graduation data with lower power, or displaying a partial or full screen in a mobile device, for example, a cell phone.

Liquid crystal display controller

There is provided a liquid crystal display control device which can display pictures in a magnification mode by using only a memory having a low-speed access and a low storage capacity. When a video signal has intermediate resolution or less, the enlargement processing is performed by a frame memory, a line memory and an enlargement processing control circuit. If the input operation and the output operation to and from the frame memory are synchronized with each other, it is sufficient for the frame memory to have a storage capacity of two lines. When the video signal has the same high resolution as a liquid crystal display panel, the video signal is output through a gate circuit to a display timing generating circuit, and it is displayed in a through mode. In this case, no processing is performed by the frame memory or the like.

Liquid crystal display control device

A generation circuit generates gray scale voltages having a plurality of levels for positive polarity and gray scale voltages having a plurality of levels for negative polarity; wherein said generation circuit, in the mode in which the number of colors to be displayed on a display panel is small, decreases a current flowing into an internal circuit which generates a gray scale voltage of an intermediate level other than two gray scale voltages of a gray scale voltage of the most lowest level and a gray scale voltage of the most highest level among the gray scale voltages of said plurality of levels, in comparison to a current flowing in the other mode; and wherein said selection circuit, in the mode in which the number of colors to be displayed on said display panel is small, selects said gray scale voltage according to said display data, from the two gray scale voltages of said most lowest level gray scale voltage and said most highest level gray scale voltage which are generated from said generation circuit.

Display apparatus and driving device for displaying

A display device for displaying display data includes a display panel having pixel sections in a matrix form, a scanning circuit which selects a line of the pixel sections, a generation circuit which generates a plurality of gray-scale voltages based on a reference voltage, and a selection circuit which selects a gray-scale voltage corresponding to the display data from the plurality of gray-scale voltages, and outputs the gray-scale voltage thus selected to a pixel section of the display panel. The generation circuit one of increases and decreases a steady-state current of the generation circuit at a second period within one scanning period of the scanning circuit.

Display device with control of steady-state current of a generation circuit

There is provided a liquid crystal display control device which can display pictures in a magnification mode by using only a memory having low-speed access and a low storage capacity. When a video signal has intermediate resolution or less, the enlargement processing is performed by a frame memory, a line memory and an enlargement processing control circuit. If the input operation and the output operation to and from the frame memory are synchronized with each other, it is sufficient for the frame memory to have a storage capacity of two lines. When the video signal has the same high resolution as a liquid crystal display panel, the video signal is output through a gate circuit to a display timing generating circuit, and it is displayed in a through mode. In this case, no processing is performed by the frame memory or the like.

A display apparatus for displaying display data, including: a first driver applying a gray scale voltage to first lines in response to display data; and a second driver applying a selection voltage to second lines in a case of selecting a line of a pixel and a non-selecting voltage to the second lines in a case of not selecting a line of a pixel, wherein the second driver in turn applies the selection voltage to each line of the second lines, wherein said second driver applies the selection voltage once per line to the second lines in one frame period, wherein the second driver applies the selection voltage to one line of the second lines in a first period of one horizontal scanning period and applies the non-selecting voltage to the same one line of the second lines in a second period of the same one horizontal scanning period.

A display driver for outputting gradation voltages corresponding to gradation data from an external device to pixels. The display driver includes a generator for generating a plurality of gradation voltages having a plurality of levels based on a reference voltage, and a selector for selecting at least one gradation voltage corresponding to the gradation data from the plurality of gradation voltages generated by the generator. The gradation data includes multi-bits for each color of red, green and blue, and the generator outputs or stops outputting each gradation voltage according to data for color reduction from the external device. The generator stops outputting at least one gradation voltage that is unnecessary for displaying as a result of the color reduction, when the color of the gradation data is reduced according to the data for color reduction.

Display device and driving circuit for displaying

A display drive circuit for outputting a gray scale voltage according to display data includes a generation circuit generating gray scale voltages of a plurality of levels, and a selection circuit which selects a gray scale voltage according to the display data. When the number of colors to be displayed is small, the generation circuit decreases a current flowing into an internal circuit which generates a gray scale voltage of an intermediate level other than two gray scale voltages of a gray scale voltage of the most lowest level and a gray scale voltage of the most highest level among the gray scale voltages of the plurality of levels, and the selection circuit selects the gray scale voltage according to the display data from the most lowest level gray scale voltage and the most highest level gray scale voltage which are generated.

A display device or a display driving device includes a display memory for storing display data; a histogram memory for storing frequencies of gray-scale voltages every line; a gray-scale voltage generation circuit for generating a plurality of gray-scale voltages on the basis of reference voltages, a current quantity of a circuit for generating each of the plurality of gray-scale voltages being changed according to a frequency of the gray-scale voltage; and a voltage selector section for selecting a gray-scale voltage to be applied to each of the plurality of pixel sections, from the plurality of gray-scale voltages.

Display device and display driving device for displaying display data

A power supply device for displaying includes a set register for setting an amplitude and voltage level of a driving voltage for a common electrode and an amplitude and voltage level of a non-selecting period voltage for a scan line, an amplitude reference generating circuit for generating an amplitude reference voltage for the driving voltage of the common electrode and for the non-selecting period voltage of the scan line according to a set value, a VcomH reference generating circuit and a VcomL generating circuit for A.C. driving the common electrode with an amplitude and voltage level determined by the amplitude reference voltage and set value, a VgoffH generating circuit and a VgoffL reference generating circuit for generating the non-selecting period voltage of the scan line with an amplitude and voltage level determined by the amplitude reference voltage and set value.

Growing community of inventors

Yokohama, Japan

Atsuhiro Higa