Patents by Inventor Masahisa Tsukahara
Masahisa Tsukahara has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8766964Abstract: Provided is an image display device including: a pixel circuit; a power supply line; a data line for supplying a data signal to the pixel circuit; and a current path control unit. The pixel circuit includes: a light emitting element; a drive transistor for controlling a current flowing to the light emitting element; a storage capacitor provided between the data line and a gate electrode of the drive transistor, for storing a potential difference; and a data line connection switch for connecting one end of the storage capacitor on the gate electrode side of the drive transistor and the data line. Before the data line supplies the data signal, the data line connection switch is turned ON, and the current path control unit interrupts a current path from the power supply line to the one end of the storage capacitor.Type: GrantFiled: May 24, 2011Date of Patent: July 1, 2014Assignees: Japan Display Inc., Canon Kabushiki KaishaInventors: Shoji Yamamoto, Junichi Yokoyama, Masahisa Tsukahara
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Patent number: 8674912Abstract: An image display device includes: a first power supply line; a second power supply line; a plurality of pixel circuit; a driving circuit for supplying a data signal and a scanning signal; and a switch unit. Each pixel circuit includes: a driving transistor between the first power supply line and the second power supply line; a light emitting element controlled by the driving transistor; and a storage capacitor for storing the data signal and controlling the driving transistor. The driving circuit causes the storage capacitor to store the data signal and controls an intensity of light emission based on the data signal. The switch unit is provided at one of one end of the first power supply line and one end of the second power supply line to control whether or not to allow a current to flow from the first power supply line to the second power supply line.Type: GrantFiled: July 15, 2010Date of Patent: March 18, 2014Assignees: Japan Displau Inc., Canon Kabushiki KaishaInventors: Norihiro Nakamura, Masahisa Tsukahara, Hajime Akimoto, Naruhiko Kasai, Takahiro Ichikawa
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Publication number: 20120139969Abstract: An image display device includes plural pixel circuits each of which includes a light emitting element where an amount of light emission changes corresponding to an amount of current and a drive transistor which controls the amount of current which flows to the light emitting element based on a display signal, a data line drive circuit which supplies a display signal to the plural pixel circuits respectively based on image data, a power source part which outputs a light-emitting potential, and a current amount prediction part which calculates an amount of current which flows to the plural pixel circuits from the power source part based on the image data. The power source part performs a control for suppressing fluctuation of the light-emitting potential based on the calculated amount of current and the outputted light-emitting potential.Type: ApplicationFiled: December 1, 2011Publication date: June 7, 2012Inventors: Junichi YOKOYAMA, Masahisa Tsukahara, Hajime Akimoto
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Publication number: 20120050252Abstract: An nMOS is used for a drive TFT and a display device is provided without being affected by variations in the threshold voltage of the drive TFT. A display device includes: a field-effect transistor that controls a drive current of a light emitting element; a first switch provided between a source of the field-effect transistor and an anode terminal of the light emitting element; a second switch provided between the source of the field-effect transistor and a signal line; a third switch provided between a drain of the field-effect transistor and a power supply line; a fourth switch provided between the drain and a gate of the field-effect transistor; a capacitor provided between the gate of the field-effect transistor and the anode terminal of the light emitting element; and a fifth switch provided between the anode terminal of the light emitting element and a predetermined voltage supply line.Type: ApplicationFiled: August 11, 2011Publication date: March 1, 2012Inventors: Hajime Akimoto, Masahisa Tsukahara, Kenta Kajiyama
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Publication number: 20110292019Abstract: Provided is an image display device including: a pixel circuit; a power supply line; a data line for supplying a data signal to the pixel circuit; and a current path control unit. The pixel circuit includes: a light emitting element; a drive transistor for controlling a current flowing to the light emitting element; a storage capacitor provided between the data line and a gate electrode of the drive transistor, for storing a potential difference; and a data line connection switch for connecting one end of the storage capacitor on the gate electrode side of the drive transistor and the data line. Before the data line supplies the data signal, the data line connection switch is turned ON, and the current path control unit interrupts a current path from the power supply line to the one end of the storage capacitor.Type: ApplicationFiled: May 24, 2011Publication date: December 1, 2011Inventors: Shoji YAMAMOTO, Junichi YOKOYAMA, Masahisa TSUKAHARA
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Publication number: 20110012817Abstract: An image display device includes: a first power supply line; a second power supply line; a plurality of pixel circuit; a driving circuit for supplying a data signal and a scanning signal; and a switch unit. Each pixel circuit includes: a driving transistor between the first power supply line and the second power supply line; a light emitting element controlled by the driving transistor; and a storage capacitor for storing the data signal and controlling the driving transistor. The driving circuit causes the storage capacitor to store the data signal and controls an intensity of light emission based on the data signal. The switch unit is provided at one of one end of the first power supply line and one end of the second power supply line to control whether or not to allow a current to flow from the first power supply line to the second power supply line.Type: ApplicationFiled: July 15, 2010Publication date: January 20, 2011Inventors: Norihiro Nakamura, Masahisa Tsukahara, Hajime Akimoto, Naruhiko Kasai, Takahiro Ichikawa
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Patent number: 7696959Abstract: Scan electrode potential detected by a feedback switch is inputted into a negative-phase input terminal of an amplifier, reference selection potential from a reference-selection-potential-signal generation circuit is inputted into a positive-phase input terminal of the amplifier, and the reference-selection-potential-signal generation circuit delays reference potential of a reference voltage source, thereby scan electrode potential without overshooting components can be achieved.Type: GrantFiled: April 20, 2006Date of Patent: April 13, 2010Assignee: Hitachi Displays, Ltd.Inventors: Hiroyuki Nitta, Masahisa Tsukahara, Toshifumi Ozaki
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Patent number: 7535439Abstract: A display device driver constructed of scanning selection switches corresponding to a plurality of scanning wiring lines, a non-selection switch which brings the scanning wiring line into a non-selected state, a feedback switch which detects a scanning electrode potential and a negative feedback amplifier which sets the scanning electrode potential to a predetermined potential every electrode based on the scanning electrode potential detected by the feedback switch, and a time constant formed of a combined capacitance of a capacitance of the feedback switch and a wiring line capacitance and a feedback switch resistance is set to be smaller than that of a display panel capacitance and a scanning selection switch resistance.Type: GrantFiled: May 15, 2006Date of Patent: May 19, 2009Assignee: Hitachi Displays, Ltd.Inventors: Hiroyuki Nitta, Masahisa Tsukahara, Toshifumi Ozaki
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Publication number: 20090001897Abstract: In the case of applying the ABL control to a display device having electron emitters disposed in a matrix, voltage drop caused by the scan line resistance is corrected, thereby displaying a preferable image without a smear. A high voltage load current limiting section for calculating drive voltage alteration data based on a high voltage load current detection signal from a high voltage load current detection section, and a scan voltage correction section for calculating a scan voltage based on the drive voltage alteration data are provided, thus the scan voltage in accordance with the high voltage load current detection signal is output to a scan line selection circuit. Further, a voltage drop correction section is provided to subtract the drive voltage alteration data from the drive voltage data obtained from image data input thereto, and signal voltage data is calculated and is output to the signal line drive circuit 15.Type: ApplicationFiled: May 27, 2008Publication date: January 1, 2009Inventors: Toshifumi Ozaki, Masahisa Tsukahara, Junichi Yokoyama
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Publication number: 20080278082Abstract: There is provided a method for driving a plasma display device characterized by including a first step of turning off first and fourth switching devices and turning on second and third switching devices, a second step of turning on the first switching device and turning off the second to the fourth switching devices after the first step and a third step of turning on the first and the fourth switching devices and turning off the second and the third switching devices after the second step.Type: ApplicationFiled: July 31, 2007Publication date: November 13, 2008Inventors: HIDEAKI OHKI, Makoto Onozawa, Masahisa Tsukahara, Hisafumi Imura
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Publication number: 20080150934Abstract: A current detection data is acquired by a scanning line current detection resistance, an adder-subtracter and an A/D converter. the current detection data is inputted to a voltage correction circuit, the voltage correction circuit output a correction signal. Using the correction signal, a scanning electrode voltage correction circuit performs the correction of the scanning selection voltage. Further, the voltage correction circuit generates data electrode drive data based on the current detection data and image data and inputs the data electrode drive data to a data electrode drive circuit. the present invention prevent a change of brightness and of smear with time.Type: ApplicationFiled: November 27, 2007Publication date: June 26, 2008Inventors: Toshifumi Ozaki, Masahisa Tsukahara, Fumio Haruna, Junichi Yokoyama, Toshimitsu Watanabe
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Publication number: 20070052655Abstract: In a display device which includes a scanning circuit, an ON resistance of a non-selection switch of the scanning circuit is set larger than an ON resistance of a selection switch. By setting the ON resistance of the non-selection switch of the scanning circuit larger than the ON resistance of the selection switch, an element size of the non selection switch can be made small and hence, a chip size of a scanning driver which is formed of a semiconductor integrated circuit constituting a scanning circuit can be made small without adversely influencing the display characteristics of the display device.Type: ApplicationFiled: August 17, 2006Publication date: March 8, 2007Inventors: Toshifumi Ozaki, Masahisa Tsukahara
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Publication number: 20060273993Abstract: A display device driver constructed of scanning selection switches corresponding to a plurality of scanning wiring lines, a non-selection switch which brings the scanning wiring line into a non-selected state, a feedback switch which detects a scanning electrode potential and a negative feedback amplifier which sets the scanning electrode potential to a predetermined potential every electrode based on the scanning electrode potential detected by the feedback switch, and a time constant formed of a combined capacitance of a capacitance of the feedback switch and a wiring line capacitance and a feedback switch resistance is set to be smaller than that of a display panel capacitance and a scanning selection switch resistance.Type: ApplicationFiled: May 15, 2006Publication date: December 7, 2006Inventors: Hiroyuki Nitta, Masahisa Tsukahara, Toshifumi Ozaki
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Publication number: 20060238456Abstract: Scan electrode potential detected by a feedback switch is inputted into a negative-phase input terminal of an amplifier, reference selection potential from a reference-selection-potential-signal generation circuit is inputted into a positive-phase input terminal of the amplifier, and the reference-selection-potential-signal generation circuit delays reference potential of a reference voltage source, thereby scan electrode potential without overshooting components can be achieved.Type: ApplicationFiled: April 20, 2006Publication date: October 26, 2006Inventors: Hiroyuki Nitta, Masahisa Tsukahara, Toshifumi Ozaki
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Publication number: 20060208671Abstract: A display device of the invention includes horizontal lines, longitudinal lines, electron emission elements, and a scanning circuit which performs the selection of the horizontal lines. The scanning circuit includes a non-selection voltage switch, a correction selection voltage switch, and an output voltage detection switch for the selected horizontal line for every horizontal line. The display device also includes a differential amplifier which is connected to a correction selection voltage input line, a horizontal line selection voltage line, and a correction selection voltage output line for every plurality of horizontal lines. The invention can suppress a voltage drop of the horizontal lines and, at the same time, can suppress the brightness irregularities of the display device.Type: ApplicationFiled: March 13, 2006Publication date: September 21, 2006Inventors: Toshifumi Ozaki, Masahisa Tsukahara, Toshiki Misonou
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Patent number: 6798460Abstract: A high definition display unit which demodulates, decodes, and processes in relation to chroma and displays a television signal in which a PI (picture) signal and an SI (service information) signal are mixed. A changeover switch 13 connected to an image quality adjusting circuit in a video chroma processing circuit 7 is opened or closed according to an on-off signal S1 showing the superposed period of both signals detected by a decoder 4. If the above on-off signal S1 is on, the changeover switch 13 is opened and the adjustment of image quality is disabled. Therefore, SI display never disappears due to the adjustment of image quality, and the quality of an image can be also adjusted according to an ambient status. Other approaches are also disclosed from preventing image quality adjustment of at least portions of a displayed image containing an information image.Type: GrantFiled: February 19, 2003Date of Patent: September 28, 2004Assignees: Hitachi, Ltd., Hitachi Video and Information System, IncorporatedInventors: Yukimi Saiki, Masahisa Tsukahara, Toshimitsu Watanabe, Kazuhiko Yoshizawa
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Publication number: 20030147009Abstract: A high definition display unit which demodulates, decodes, and processes in relation to chroma and displays a television signal in which a PI (picture) signal and an SI (service information) signal are mixed. A changeover switch 13 connected to an image quality adjusting circuit in a video chroma processing circuit 7 is opened or closed according to an on-off signal S1. showing the superposed period of both signals detected by a decoder 4. If the above on-off signal S1. is on, the changeover switch 13 is opened and the adjustment of image quality is disabled. Therefore, SI display never disappears due to the adjustment of image quality, and the quality of an image can be also adjusted according to an ambient status. Other approaches are also disclosed from preventing image quality adjustment of at least portions of a displayed image containing an information image.Type: ApplicationFiled: February 19, 2003Publication date: August 7, 2003Inventors: Yukimi Saiki, Masahisa Tsukahara, Toshimitsu Watanabe, Kazuhiko Yoshizawa
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Patent number: 6563546Abstract: A high definition display unit which demodulates, decodes, and processes in relation to chroma and displays a television signal in which a PI (picture) signal and an SI (service information) signal are mixed. A changeover switch 13 connected to an image quality adjusting circuit in a video chroma processing circuit 7 is opened or closed according to an on-off signal SI showing the superposed period of both signals detected by a decoder 4. If the above on-off signal SI is on, the changeover switch 13 is opened and the adjustment of image quality is disabled. Therefore, SI display never disappears due to the adjustment of image quality, and the quality of an image can be also adjusted according to an ambient status. Other approaches are also disclosed from preventing image quality adjustment of at least portions of a displayed image containing an information image.Type: GrantFiled: March 29, 2002Date of Patent: May 13, 2003Assignees: Hitachi, Ltd., Hitachi Video and Information System, IncorporatedInventors: Yukimi Saiki, Masahisa Tsukahara, Toshimitsu Watanabe, Kazuhiko Yoshizawa
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Patent number: 6529245Abstract: A digital television signal receiver includes a decoder, capable of decoding digital television signals having a plurality of different formats, which outputs video information in which image fields having mutually different numbers of scanning lines appear aperiodically when the decoder decodes a digital television signal having a specific one of the different formats; a display device which displays an image based on the video information output from the decoder; and an image controller which sets respective display start positions for the image fields having mutually different numbers of scanning lines to a same display start position in a vertical direction when the display device displays an image based on the video information output from the decoder when the decoder decodes the digital television signal having the specific format.Type: GrantFiled: September 12, 2001Date of Patent: March 4, 2003Assignees: Hitachi, Ltd., Hitachi Video and Information Sysmte, Inc.Inventors: Toshimitsu Watanabe, Yukimi Saiki, Kazuhiko Yoshizawa, Masahisa Tsukahara
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Patent number: 6433832Abstract: When a video signal is double-speed processed by the first device, a slight vertical deflection process is performed for redundant similar scan lines by the second device, and any slight deflection in the second device is controlled by the first device to enable setting so as to display images with excellent resolution. The first device generates a discrimination signal to designate interlaced scanning and flag a need for vertical scan-line deflection, and such signal is provided to the second device such that the second device can always appropriately determine need for vertical scan-line deflection. Through monitoring for the discrimination signal, an image display apparatus can prevent vertical resolution from deteriorating when video signals possibly requiring vertical line-shifting are inputted from an external source, and can prevent vertical resolution from deteriorating when displaying images of video signals having different systems within different areas on the same screen.Type: GrantFiled: June 11, 2001Date of Patent: August 13, 2002Assignees: Hitachi, Ltd., Hitachi Video and Information System, IncorporatedInventors: Toshimitsu Watanabe, Masahisa Tsukahara, Nobuaki Kabuto