Sharp Kabushiki Kaisha Corporation

Michiaki Takeda

Mamoru Takaya

Eishi Oda

Hiroyoshi Kure

A touch panel controller is equipped with a control unit that outputs a decimation signal to a drive line driving circuit when touch response magnitude data is a designated value or greater, or in other words, when the distance between a touch panel and a stylus pen is closer than a designated value. Thus, it is possible to realize a touch panel system able to moderate the amount of power consumed when synchronizing drive timings between the pen and the touch panel controller that drives the touch panel, and thereby operate with low power consumption.

Proximity-dependent adjustable-signal touch panel system

In a touch panel system of the present invention, a touch pen is configured of an electronic pen that signals can be input into and output from. A touch panel controller includes a synchronization signal transmission unit that transmits a synchronization signal to the electronic pen during synchronization signal transmission periods immediately before each of a first signal line drive period and a second signal line drive period. The synchronization signal transmission unit transmits the synchronization signal of which the waveform is configured of a Manchester-coded pseudorandom sequence having periodicity to the electronic pen during the synchronization signal transmission period. The electronic pen includes a synchronization signal detecting unit that detects the synchronization signal.

Touch panel system and electronic device

In a touch panel system () of the present invention, a stylus pen () produces output that indicates that a quantitative characteristic value is increased from the characteristic value of a previous output by using a waveform that corresponds to an (L+1)-th drive line (DL) other than L numbers of drive lines (DLto DL) and, meanwhile, produces output that indicates that the quantitative characteristic value is decreased from the characteristic value of the previous output by using a waveform that corresponds to an (L+2)-th drive line (DL) other than the L numbers of drive lines (DLto DL). A touch panel controller () includes a conversion output unit () that converts and outputs the quantitative characteristic value by using the sum of the initial value of the quantitative characteristic value and the number of outputs&#xd7;the unit amount of increase or decrease in the waveform that corresponds to the (L+1)-th drive line (DL) or in the waveform that corresponds to the (L+2)-th drive line (DL).

The present invention effectively suppresses not only occurrences of halos but also degradation of the black level. This image display device has a liquid crystal panel () that displays images according to an image signal and a backlight () in which LEDs are used and controls the light emission brightness of the LEDs for each division region, which is obtained by dividing the backlight () into a plurality of regions, on the basis of a prescribed relation between a gradation value for an image region corresponding to each division region and the LED light emission brightness. When the gradation value for an image satisfies prescribed conditions, a first luminance adjusting portion () adjusts the LED light emission brightness such that the range of variation in LED light emission brightness in a first range for the gradation value of the image region, which is determined on the basis of the prescribed conditions above, is smaller than the range of variations for the LED light emission brightness that is determined on the basis of the prescribed relation above, and a second luminance adjusting portion () adjusts the LED light emission brightness in a second range for which the value is smaller than the first range such that the light emission brightness is smaller than a lower limit value for the LED light emission brightness adjusted above.

Video display device

Light leakage and black float are reduced in dark ambient while a perception of high contrast is achieved when a backlight is divided into a plurality of areas and backlight brightness is controlled depending on a video signal corresponding to each area. An area active control portion () divides a video signal into a plurality of areas and outputs a first feature value for each area. An LED control portion () acquires a first brightness for each divided area of an LED backlight () depending on the first feature value of each area, and acquires a second brightness for each area that is acquired by uniformly multiplying a specific multiplying factor acquired depending on the lighting ratio of the LED backlight () with respect to the first brightness within a range where a total value of the LED driving current does not exceed a predetermined permissible current value. When the lighting ratio of the LED backlight () is at or below a predetermined value, the second brightness is reduced in accordance with ambient lighting detected by a photosensor () to acquire a third brightness.

Growing community of inventors

Osaka, Japan

Michiaki Takeda