Denso Corporation

Nippondenso Co., Ltd.

Koji Ogusu

Naoki Matsumoto

Takashi Hanaki

Takaharu Idogaki

Manabu Otsuka

Masahiko Osada

Kazuhiro Inoguchi

Takahisa Kaneko

Shogo Kameyama

Takeshi Ishikawa

Hiroyuki Kishita

Shinichi Tamura

Tomohiro Kuno

Michio Kameyama

Yoichi Kotanshi

Kiyohito Narita

A driving method for driving luminous elements has a luminous element provided at each intersection of anode lines and cathode lines arranged in a matrix. The anode lines are one of scan lines and drive lines and the cathode lines are one of other of scan lines and drive lines. The luminous element provided at an intersection of a desired drive line is driven to emit light in synchronism with scanning while scanning the scan lines at a specific frequency. When switching the scanning line, at least one of the scanning lines is first connected to a first voltage, and the remaining scanning lines are connected at the same time to a second voltage that is different from the first voltage.

Driving method for luminous elements

A segment-type electroluminescent display panel is driven by a driving circuit that supplies a constant current to each luminescent segment. The display panel includes plural luminescent segments each having a luminescent area different from one another. The plural segments are grouped into several groups, so that each group includes the segments having the same or similar luminescent area. The amount of current to be supplied to each segment is determined group by group so that a substantially same current density is supplied to all the segments. Since the plural segments are grouped according to their size, the driving circuit is simplified while attaining an equal luminance among all the luminescent segments. Alternatively, an equal amount of current is supplied to all the variously sized segments, and a resistor is connected in parallel to each segment to equalize the current density supplied to each segment thereby to achieve an equal luminance among all the segments.

Device having multiple luminescent segments

In an electroluminescent (EL) display device having a plurality of organic EL elements, variations in luminance among the EL elements are equalized. EL elements to be driven for a required image display are periodically applied with drive voltages and a recovery voltage, while the other EL elements are periodically applied with a dummy voltage. The period, the repetition period, and the amplitude of the dummy voltage are set not to illuminate the other EL elements, while promoting degradation of the other EL elements to some extent. Alternatively, the drive voltage applied to drive the EL elements for the required image display may be modified in accordance with the degree of degradation thereof.

Organic electroluminescent display device having luminance degradation compensating function

A transparent electroluminescent display panel overlaps at least a part of a conventional instrument panel, and forms a combined display panel assembly. Overlapping front and back panel displays are selectively displayed. The front electroluminescent panel displays additional information such as navigation maps, and is turned off when such additional information is not required while the back panel is turned on. The present invention eliminates undesirable reflected images of the back panel vaguely shown on the front panel when the front panel is on and the back panel is off. A light attenuator, eliminates the reflected images. It decreases the intensity of light emitted from the front panel to the back panel, and is disposed between the back and the front panels or built into the electroluminescent panel, so that the reflected images are eliminated.

Combined display panel

A flat display panel having electroluminescent layer and scanning and data electrodes is driven by driving circuits connected to the respective electrodes. Scanning voltages are sequentially supplied to the scanning electrodes one by one, and data voltages are supplied to the data electrodes in synchronism with the scanning voltages, thereby selectively imposing composite voltages on pixels formed at each intersection of the scanning and data electrodes. The pixels on one scanning electrode that is already scanned are charged to a level of a data modulation voltage to prevent a harmful and useless turnaround current from flowing into the scanned pixels when other scanning electrodes are scanned. The pixels on other scanning electrodes that are not yet scanned may be charged to the modulation voltage level at the same time the scanned pixels are charged. Since the turnaround current is thus eliminated, uneven brightness among scanning electrodes otherwise appearing on the display panel is suppressed.

Electroluminescent display device

A mobile communication device can perform direct communication with another mobile communication device without providing a new communication circuit. The mobile device moves by driving wheels rotated by a motor. A pressure sensor is provided on an outer surface of the body of the communication device to detect contact pressure with another mobile communication device. A control circuit maintains a constant level of driving force of the motor when the communication device is in contact with another mobile communication device and receives data by determining changes in the detected contact pressure which correspond to the predetermined transmission data. Alternately, data exchanges maybe performed using the relative distance between the communication devices.

Mobile communication device having a direct communication capability

Control units U.sub.i-1, U.sub.i and U.sub.i+1, each having a piezoelectric actuator 3, are aligned on a resilient substrate 1 at predetermined intervals, so as to constitute a united control system. An actuator controller, formed on a circuit substrate 4 of control unit U.sub.i, receives target displacements of neighboring other control units U.sub.i-1 and U.sub.i+1. Then, using a discrete difference equation derived from the partial differential equation describing the distributed parameter system model of the united control system, the displacement amount of control unit U.sub.i can be determined based on the target displacement of the control unit U.sub.i and the target displacements of the neighboring other control units U.sub.i-1 and U.sub.i+1 thereby driving piezoelectric actuator 3 smoothly.

United control system comprising a plurality of control units

To provide a tire pressure estimating system which is capable of estimating tire pressure based on a signal representing the rotational speed of a vehicle wheel via a small amount of processing by using low-capacity memory, a wheel speed sensor is provided for each wheel of a vehicle. A pulse signal output by the wheel speed sensor is supplied to a signal processor. In the signal processor, the rotational speed of each vehicle wheel is found from the pulse signal. The signal processor adopts a second-order linear prediction model for the rotational speed of the vehicle wheel and vibration of the tire using parameters identified from values of the rotational speed. A resonance frequency is then found from the identified parameters. Finally, the tire pressure is estimated from a linear relationship between the pressure and the resonance frequency.

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Kariya, Japan

Koji Ogusu