Sharp Kabushiki Kaisha Corporation

Yasunori Ake

Tomohiko Yamamoto

Naoto Inoue

Yasukuni Yamane

Tomoyuki Ishihara

Hideki Ichioka

Koji Fujiwara

Kenta Fukuoka

There is provided an image display device that includes a display in which a background is transparently seen from a front surface side, and has a high degree of freedom at the time of installation. A liquid crystal panel () for adjusting transparency/light-emission adjusts, for each pixel, a ratio between transmitted light-source light and ambient light by respectively controlling a polarization direction of a reflected polarization component of the light-source light irradiated to a reflection-type polarization plate () from a light guide plate () and a polarization direction of a transmitted polarization component of the ambient light incident to the reflection-type polarization plate () from a rear surface side of the display, based on transparent/light-emitting pixel information. Accordingly, when the image display device is viewed from the front surface side of the display, an image is seen for each pixel, a background is transparently seen, or the background is seen so as to be superimposed on the image. Since it is not necessary to attach the image display device to a case filled with light, the image display device is widely used without limitation of use.

Image display device

A display device that adopts a field sequential method and that is capable of achieving desired luminance while suppressing mixing of colors is provided. With respect to display of each color by a liquid crystal display device adopting a field sequential method, a period is provided for which light sources of each color remain turned on until a turning-off delay time has elapsed since an end timing of a subframe period. The turning-off delay time relating to LEDs for which an off state begins in a preceding subframe period is configured in such a way as to be shorter than a turning-on delay time relating to LEDs for which an on state begins in a succeeding subframe period. As a result, an all-off period, in which LEDs of all colors are in the off state, is provided between on periods of two colors.

Display device and method that divides one frame period into a plurality of subframe periods and that displays screens of different colors in accordance with the subframe periods

A first arithmetic section is provided that calculates a first time, which is a time period from a transmission timing of a ultrasonic wave to a reception recognized timing at which a wave height value of the ultrasonic wave received by an ultrasonic wave receiving section crosses a predetermined threshold for a first predetermined number of times. A second arithmetic section is provided that calculates a second time as the propagation time of the ultrasonic wave, the second time being a time period from the transmission timing of the ultrasonic wave to a reception confirmed timing, which is a timing after the wave height value has crossed the predetermined threshold for a second predetermined number of times and before the wave height value crosses the predetermined threshold again, wherein the second arithmetic means varies the second predetermined number according to the first time. In this way, coordinates of a pointing device employing ultrasonic wave can be obtained with less error variation.

Coordinates input system, coordinates input method, coordinates input program, and computer-readable storage medium

The coordinate input pen according to the present invention is a coordinate input pen for specifying a current position of the coordinate input pen by emitting an ultrasonic wave, including: an ultrasonic wave oscillating section for oscillating the ultrasonic wave for specifying coordinates of the current position; an ultrasonic wave emitting outlet for emitting, to an outside, the ultrasonic wave oscillated by the ultrasonic wave oscillating section; and an ultrasonic wave propagation route which has a fixed length and extends from the ultrasonic wave oscillating section to the ultrasonic wave emitting outlet and is used to propagate the ultrasonic wave to the ultrasonic wave emitting outlet. As a result, it is possible to maintain the output level of the ultrasonic wave oscillated by the ultrasonic wave oscillating section constant regardless of how large a stroke pressure applied on the coordinate input pen is.

Coordinate input pen and coordinate input apparatus having the same

When a display panel is in contact with the pen tip of an input pen, an infrared receiver and at least two ultrasonic receivers, provided on the display panel, receive respectively an infrared signal and an ultrasonic signal simultaneously transmitted from an infrared transmitter and an ultrasonic transmitter, and computes the contact position of the pen tip on the display panel from a result, containing a time delay, of the ultrasonic receiver receiving the ultrasonic signal with reference to a time when infrared signal is received. The input pen includes a piezoelectric element sensing pen pressure when the pen tip is in contact with the display panel and a microcomputer controlling a infrared transmitter to transmit an infrared signal which changes in accordance with the pen pressure. Thus, in ultrasonic pen input operation, information on the sensed pen pressure is wirelessly transmitted to the device main body, so as to provide a pen input/display device realizing multifunctional, high performance pen input operation based on the pen pressure information in a simple manner.

Pen input/display device

A coordinate input system includes: a digitizer for indicating coordinate positions; a controller for extracting a plurality of coordinate data units from the indicated coordinate positions; a temporary storage memory for sequentially storing the extracted coordinate data units; a cosine value deriving section for defining vectors each connecting two of points associated with the respective coordinate data units and for deriving a cosine value of an angle formed by adjacent two of the vectors sandwiching a point selected from the points; and a control circuit for discarding one of the coordinate data units associated with the selected point when the cosine value is smaller than a given value and for transmitting and inputting one of the coordinate data units associated with the selected point when the cosine value is equal to or larger than the given value.

Growing community of inventors

Kashihara, Japan

Yasunori Ake