Abstract: 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 (32) 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 (20) from a light guide plate (180) and a polarization direction of a transmitted polarization component of the ambient light incident to the reflection-type polarization plate (20) from a rear surface side of the display, based on transparent/light-emitting pixel information.

Abstract: 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 (32) 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 (20) from a light guide plate (180) and a polarization direction of a transmitted polarization component of the ambient light incident to the reflection-type polarization plate (20) from a rear surface side of the display, based on transparent/light-emitting pixel information.

Abstract: 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.

Abstract: 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.

Abstract: The present invention provides an image display device capable of maintaining appropriate display luminance for human visual properties. The image display device of the present invention includes: a display device main body (20) having a display section (21) and a light source (24); and viewing means (glasses (10)) that a viewer is able to wear in viewing a video picture displayed on the display section (21). The viewing means (10) includes (i) a light reception detecting section (13) that detects the intensity of incident light (ii) and a signal transmitting section (14) that transmits, to the display device main body (20), detection signals obtained by the light reception detecting section (13) detecting the intensity of the incident light. The display device main body (20) includes a luminance control section (23) that controls the luminance of the display section (21) by controlling the luminance of the light source (24) in accordance with the detection signals.

Abstract: 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.

Abstract: 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.

Abstract: An illuminating device is provided with a plurality of light source modules (LM) each of which has a light emitting element and a driver circuit for driving the light emitting element, and the illuminating device controls the driver circuit of each light source module individually. All the light. source modules are grouped by having a plurality of light source modules arranged at intervals (d) as one group. A step of lighting light emitting bodies of the light source modules in the same group (for instance, LM (1, 1)·LM (1, 9)) simultaneously under predetermined conditions is performed in turn for all the groups. Based on the obtained light emitting quantity of the light emitting element of each light source module (LM), the driver circuit of the light source module is controlled. Thus, in a backlight device provided with a plurality of illuminating areas, the light emitting quantity in each illuminating area can be accurately corrected in a short time.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.