Hitachi, Ltd.

Other

Renesas Electronics Corporation

Hitachi Device Engineering Co., Ltd.

Renesas Technology Corp.

Hitachi Video and Information System, Inc.

Kazunari Kurokawa

Yasuyuki Kudo

Akihito Akai

Kazuo Ookado

Atsuhiro Higa

Hiroki Aizawa

Yoshikazu Yokota

Akira Ogura

Takahiro Fujioka

Hiroshi Kurihara

Mitsuru Goto

Kentaro Agata

Yukihide Ode

Hiroshi Katayanagi

Tsutomu Furuhashi

Tatsuhiro Inuzuka

Toshimitsu Matsudo

Hideaki Abe

Hiroshi Watanabe

Shinji Yasukawa

Hironobu Abe

Hiroyuki Takahashi

Atsushiro Higa

Noboru Kataoka

Kazuyuki Kitagawa

A liquid crystal display system including: a liquid crystal display panel for displaying image data; a semiconductor device including a display driving circuit configured to drive the liquid crystal display panel, said display driving circuit having a function of generating gray scale voltages based on a gamma characteristic curve, said display driving circuit including: an interface circuit coupled to plurality of external terminals for inputting a first, second and third value which define the gamma characteristic curve; a first register configured to store the first value that adjusts an amplitude of the gamma characteristic curve; a second register configured to store the second value that adjusts a gradient of the gamma characteristic curve; a third register configured to store the third value making a micro adjustment of the gamma characteristic curve; and a generation circuit configured to generate the gray scale voltages based on the gamma characteristic curve.

Display apparatus and driving device for displaying

Display driving arrangements including: generation circuit dividing a reference voltage by variable resistors for plural levels of voltages; a decoder circuit decoding gray scale voltage corresponding to the display data among the levels of voltages; and a register setting variable resisters resistance values to adjust amplitude and gradient of the gamma characteristic curve of the gray scale voltages with respect to the gray scale number, the generation circuit having a group of resistive voltage dividing circuits dividing the reference voltage, a variable resister amplitude adjusting the gamma characteristic curve in accordance with register setting values connected with a side of the reference voltage in series, being closer to the side of the reference voltage than the group of resistive voltage dividing circuits, a variable resister to adjust the gradient of the gamma characteristic curve per the register setting values connected within the group of resistive voltage dividing circuits in series.

A display driving circuit to supply a gray scale voltage corresponding to display data to a display panel, the display driving circuit including: a generation circuit to divide a reference voltage to generate a plurality of levels of the gray scale voltages; an interface circuit; a selection circuit to select the gray scale voltage corresponding to the display data from the plurality of levels of voltages; a first register to store a setting value that adjusts the amplitude of a gamma characteristic curve from outside via the interface circuit; and a second register to store a setting value that adjusts the gradient of the gamma characteristic curve from outside via the interface circuit; and a third register to store a setting value for micro adjusting the gamma characteristic curve from outside via the interface circuit; wherein the first, second and third registers are assigned different addresses.

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.

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

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 adjustable for a gamma specification of a liquid display panel, including: a system interface receiving display data from an external; a memory storing the display data; a grayscale voltage generator generating a plurality of grayscale voltages; a gamma adjusting circuit adjusting the gamma specification; and an output circuit outputting the grayscale voltage in response to the display data from the memory to the liquid display panel, wherein the gamma adjusting circuit includes: a gradient adjustment register controlling variable resistors of a ladder resistor; an amplitude/reference adjustment register; and a micro adjustment register, wherein the gradient adjustment register, the amplitude/reference adjustment register and micro adjustment register, are independently set in accordance with red, green and blue, respectively.

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 matrix type liquid crystal display device has a function of suppressing power consumption without calling for an extra circuit arrangement such as the arrangement of storage capacitance and wiring to storage capacitance and without disposing new external components. A switch is disposed in the liquid crystal display device to temporarily short-circuit both column electrodes and common electrodes sandwiching a liquid crystal between them in synchronism with an alternation timing.

Liquid crystal drive circuit and liquid crystal display device

A driving display device includes a gray scale voltage generating circuit for generating a plurality of levels of gray scale voltages from a reference voltage, an amplitude adjustment register capable of setting the amplitude of a characteristic curve of a plurality of levels of the gray scale voltages with respect to gray scale numbers, and a gradient adjustment register capable of setting the gradient of the characteristic curve. With this arrangement, the gradient and amplitude of the gray scale number-gray scale voltage characteristic are adjusted.

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.

Display apparatus and power supply device for displaying

A display apparatus and a display drive circuit are disclosed. The display drive circuit comprises a gate line drive circuit and a register. The gate line drive circuit outputs to the pixels a select voltage for selecting the pixels and a non-select voltage for prohibiting the selection of the pixels during one horizontal period. The register sets a non-overlap period for outputting a non-select voltage to at least two lines of pixels on the display panel during one horizontal period.

Growing community of inventors

Mobara, Japan

Kazunari Kurokawa