Patents by Inventor Masafumi Yashiki
Masafumi Yashiki 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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Publication number: 20220189420Abstract: An image display apparatus includes a display panel including multiple pixels, a backlight including multiple white-light light sources, a panel driving circuit, a backlight driving circuit, and a determination circuit determining image data. The white-light light sources have characteristics that cause afterglow of a particular color to persist longer than afterglow of another color. The backlight driving circuit segments the backlight into multiple areas and drives the backlight such that a time duration of performing control to cause the areas to sequentially be in a light-emission state at mutually different timings alternates with a time duration of performing control to cause all the areas to be in a non-light-emission state. The determination circuit determines a determination value indicating a degree of inclusion at which achromatic data is included in the image data and determines a light-emission start timing of each of the areas in accordance with the determination value.Type: ApplicationFiled: November 18, 2021Publication date: June 16, 2022Inventors: Masamitsu KOBAYASHI, Takafumi MIURA, Masafumi YASHIKI
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Patent number: 10877315Abstract: A liquid crystal driving frequency detection unit that determines a liquid crystal driving frequency based on a vertical synchronization signal is provided in an LED drive circuit. In addition, a look-up table that holds a correspondence relationship between the liquid crystal driving frequency and the lighting frequency of the LEDs is provided in a control unit in the LED drive circuit. The correspondence relationship is held in the look-up table such that, for example, when the liquid crystal driving frequency becomes one-nth of that before change, the lighting frequency of the LEDs becomes n times of that before change. The LED drive circuit determines the lighting frequency of the LEDs by referring to the look-up table when the liquid crystal driving frequency changes.Type: GrantFiled: February 10, 2020Date of Patent: December 29, 2020Assignee: SHARP KABUSHIKI KAISHAInventor: Masafumi Yashiki
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Patent number: 10854167Abstract: A display device includes a display panel, a frame memory, a display control circuit that performs a predetermined process on a first video signal using the frame memory and outputs an obtained second video signal, and a panel drive circuit that drives the display panel based on the second video signal. The display control circuit checks whether the frame memory is normal or abnormal, by storing partial video data included in the first video signal, writing to the frame memory, video data obtained by replacing the partial video data with first test data, and comparing with the first test data, second test data included in the video data read from the frame memory.Type: GrantFiled: June 24, 2019Date of Patent: December 1, 2020Assignee: SHARP KABUSHIKI KAISHAInventors: Noriaki Yamaguchi, Hidekazu Miyata, Masafumi Yashiki
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Publication number: 20200264476Abstract: A liquid crystal driving frequency detection unit that determines a liquid crystal driving frequency based on a vertical synchronization signal is provided in an LED drive circuit. In addition, a look-up table that holds a correspondence relationship between the liquid crystal driving frequency and the lighting frequency of the LEDs is provided in a control unit in the LED drive circuit. The correspondence relationship is held in the look-up table such that, for example, when the liquid crystal driving frequency becomes one-nth of that before change, the lighting frequency of the LEDs becomes n times of that before change. The LED drive circuit determines the lighting frequency of the LEDs by referring to the look-up table when the liquid crystal driving frequency changes.Type: ApplicationFiled: February 10, 2020Publication date: August 20, 2020Inventor: MASAFUMI YASHIKI
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Patent number: 10665179Abstract: A display device has a light unit including a light source, and a display panel, which the rear surface of the display panel has transmissive. The display device has a first display mode of turning ON the light source and displaying a color image in a display region of the display panel, and a second display mode of turning OFF the light source and displaying a transmitted light image including a transmissive region in the display region. The display device detects whether or not a observer of the display device exists around and switches into the second display mode upon detection of the observer.Type: GrantFiled: January 25, 2019Date of Patent: May 26, 2020Assignee: SHARP KABUSHIKI KAISHAInventor: Masafumi Yashiki
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Publication number: 20200051523Abstract: A display device includes a display panel, a frame memory, a display control circuit that performs a predetermined process on a first video signal using the frame memory and outputs an obtained second video signal, and a panel drive circuit that drives the display panel based on the second video signal. The display control circuit checks whether the frame memory is normal or abnormal, by storing partial video data included in the first video signal, writing to the frame memory, video data obtained by replacing the partial video data with first test data, and comparing with the first test data, second test data included in the video data read from the frame memory.Type: ApplicationFiled: June 24, 2019Publication date: February 13, 2020Inventors: Noriaki YAMAGUCHI, Hidekazu MIYATA, Masafumi YASHIKI
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Publication number: 20200051484Abstract: An LED data holding unit that holds turn-on control data for controlling the luminance of each LED included in a backlight device is provided in an LED drive circuit. The LED data holding unit is implemented by, for example, registers. When the LED drive circuit drives the LEDs, the LED drive circuit switches a read destination of the turn-on control data from the LED data holding unit based on a turn-on switching signal. Turn-on control data for each LED is read from the LED data holding unit a ty of times during each frame period.Type: ApplicationFiled: July 15, 2019Publication date: February 13, 2020Inventor: MASAFUMI YASHIKI
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Patent number: 10460676Abstract: Provided is a display device for making an easily viewed display of both an image displayed in an image display region and a background displayed in a transparent display region when driven by a field sequential system. When a liquid crystal display device provided with a liquid crystal panel divided into an image display region and a transparent display region is driven by a field sequential system, the transparent display region) is given WRGB data for transparent display generated with transparency as a priority, and the image display region is given WRGB data for image display generated with color breakup reduction as a priority. Furthermore, backlight light from a light-emitting region provided on a light guide plate disposed on the back surface side of the liquid crystal panel is irradiated in the image display region. Thus, the background can be displayed with high transparency in the transparent display region and the image can be displayed with low color breakup in the image display region.Type: GrantFiled: July 16, 2015Date of Patent: October 29, 2019Assignee: Sharp Kabushiki KaishaInventor: Masafumi Yashiki
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Publication number: 20190237028Abstract: A display device has a light unit including a light source, and a display panel, which the rear surface of the display panel has transmissive. The display device has a first display mode of turning ON the light source and displaying a color image in a display region of the display panel, and a second display mode of turning OFF the light source and displaying a transmitted light image including a transmissive region in the display region. The display device detects whether or not a observer of the display device exists around and switches into the second display mode upon detection of the observer.Type: ApplicationFiled: January 25, 2019Publication date: August 1, 2019Inventor: MASAFUMI YASHIKI
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Patent number: 10366665Abstract: A signal processing circuit comprising: a signal separation unit separating an input video signal into components of individual colors; an expanded video signal generation unit performing an expansion process for increasing a signal value of the input video signal, and outputting data obtained by the expansion process as an expanded video signal; an expansion coefficient decision unit deciding an expansion coefficient to be used for the expansion process; and an output video signal generation unit generating an output video signal for output to the display panel based on the expanded video signal. The expansion coefficient decision unit decides the inverse of the saturation as the expansion coefficient for a pixel, at which the saturation is not smaller than a predetermined value, and decides the expansion coefficient based on a quadratic function.Type: GrantFiled: September 16, 2016Date of Patent: July 30, 2019Assignee: SHARP KABUSHIKI KAISHAInventors: Masafumi Yashiki, Ryohei Koizumi
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Patent number: 10347194Abstract: A display device (10) includes a light source (19), a light guide plate (18), a display panel (11), a panel driving unit that outputs, to the display panel (11), a signal for controlling a transmittance of each pixel of the display panel (11), and a light source driving unit (16). Light can pass through a back surface of the light guide plate (18), which is a surface opposed to the emission surface of the light guide plate (18). The light source driving unit (16) drives the light source (19) based on the lighting control data. In a case where an image is displayed when the light source (19) is in ON state, the display panel (11) displays a color image, by controlling, pixel by pixel, a transmittance of light that passes from the light source (19) through the emission surface of the light guide plate.Type: GrantFiled: December 17, 2015Date of Patent: July 9, 2019Assignee: SHARP KABUSHIKI KAISHAInventor: Masafumi Yashiki
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Publication number: 20180286327Abstract: A display device expanding a color space without an increase in IC size, in cost, and in display problems. A signal processing circuit comprising: a signal separation unit separating an input video signal into components of individual colors; an expanded video signal generation unit performing an expansion process for increasing a signal value of the input video signal, and outputting data obtained by the expansion process as an expanded video signal; an expansion coefficient decision unit deciding an expansion coefficient to be used for the expansion process; and an output video signal generation unit generating an output video signal for output to the display panel based on the expanded video signal. The expansion coefficient decision unit decides the inverse of the saturation as the expansion coefficient for a pixel, at which the saturation is not smaller than a predetermined value, and decides the expansion coefficient based on a quadratic function.Type: ApplicationFiled: September 16, 2016Publication date: October 4, 2018Inventors: MASAFUMI YASHIKI, RYOHEI KOIZUMI
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Patent number: 10074322Abstract: An object of the present invention is to realize a liquid crystal display device of a field sequential system which is capable of preventing occurrence of color shift and flicker. One frame period is divided into a plurality of fields, the number of which is greater than the number of lighting patterns. Provided are a liquid crystal state value acquiring unit (131) configured to obtain a liquid crystal state value at an end time of a display field based on an input gradation value in the display field and a liquid crystal state value at an end time of a previous field (one field before the display field) (a gradation value corresponding to an aligned state of liquid crystal molecules), and an application gradation value acquiring unit (133) configured to obtain an application gradation value in the display field by correcting an input gradation value in the display field based on a liquid crystal state value at the end time of the previous field.Type: GrantFiled: July 3, 2015Date of Patent: September 11, 2018Assignee: SHARP KABUSHIKI KAISHAInventors: Hidekazu Miyata, Masafumi Yashiki, Takenobu Nishiguchi
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Patent number: 9966014Abstract: A field sequential processing unit 11 includes a representative value calculating unit 111 configured to obtain a representative value for each pixel based on video data Ri, Gi, and Bi, a backlight data generating unit 112 configured to generate backlight data Xb indicating brightness of LEDs 18 in each area of the backlight 17 based on the obtained representative value, a video data correcting unit 113 configured to correct the video data Ri, Gi, and Bi based on the backlight data Xb, and a field data generating unit 114 configured to generate four pieces of field data Wf, Rf, Gf, and Bf based on the corrected video data Rc, Gc, Bc. By generating the backlight data based on the representative value for each pixel, it is possible to reduce a size of a circuit for obtaining brightness of the backlight for each area.Type: GrantFiled: September 4, 2014Date of Patent: May 8, 2018Assignee: SHARP KABUSHIKI KAISHAInventor: Masafumi Yashiki
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Publication number: 20170372668Abstract: A display device (10) includes a light source (19), a light guide plate (18), a display panel (11), a panel driving unit that outputs, to the display panel (11), a signal for controlling a transmittance of each pixel of the display panel (11), and a light source driving unit (16). Light can pass through a back surface of the light guide plate (18), which is a surface opposed to the emission surface of the light guide plate (18). The light source driving unit (16) drives the light source (19) based on the lighting control data. In a case where an image is displayed when the light source (19) is in ON state, the display panel (11) displays a color image, by controlling, pixel by pixel, a transmittance of light that passes from the light source (19) through the emission surface of the light guide plate.Type: ApplicationFiled: December 17, 2015Publication date: December 28, 2017Inventor: MASAFUMI YASHIKI
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Publication number: 20170263190Abstract: Provided is a display device for making an easily viewed display of both an image displayed in an image display region and a background displayed in a transparent display region when driven by a field sequential system. When a liquid crystal display device provided with a liquid crystal panel divided into an image display region and a transparent display region is driven by a field sequential system, the transparent display region is given WRGB data for transparent display generated with transparency as a priority, and the image display region is given WRGB data for image display generated with color breakup reduction as a priority. Furthermore, backlight light from a light-emitting region provided on a light guide plate disposed on the back surface side of the liquid crystal panel is irradiated in the image display region. Thus, the background can be displayed with high transparency in the transparent display region and the image can be displayed with low color breakup in the image display region.Type: ApplicationFiled: July 16, 2015Publication date: September 14, 2017Applicant: Sharp Kabushiki KaishaInventor: Masafumi YASHIKI
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Publication number: 20170256211Abstract: An object of the present invention is to realize a liquid crystal display device of a field sequential system which is capable of preventing occurrence of color shift and flicker. One frame period is divided into a plurality of fields, the number of which is greater than the number of lighting patterns. Provided are a liquid crystal state value acquiring unit (131) configured to obtain a liquid crystal state value at an end time of a display field based on an input gradation value in the display field and a liquid crystal state value at an end time of a previous field (one field before the display field) (a gradation value corresponding to an aligned state of liquid crystal molecules), and an application gradation value acquiring unit (133) configured to obtain an application gradation value in the display field by correcting an input gradation value in the display field based on a liquid crystal state value at the end time of the previous field.Type: ApplicationFiled: July 3, 2015Publication date: September 7, 2017Inventors: Hidekazu MIYATA, Masafumi YASHIKI, Takenobu NISHIGUCHI
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Publication number: 20170047021Abstract: There is provided a field-sequential-system display device that reduces or eliminates a color mixture phenomenon while suppressing a reduction in luminance. In a field-sequential-system liquid crystal display device, when one frame period is divided into three subframe periods, red, green, and blue backlights are lit during light-on periods which are the second half of a first to a third subframe period, and the operation of writing an image to pixel formation portions is performed twice using two scanning periods each being shorter in length than the first half of each subframe period. By this configuration, pixel voltages are securely written to pixel capacitances, and color mixture with a color in a previous subframe period is prevented by a period other than a light-on period.Type: ApplicationFiled: May 28, 2015Publication date: February 16, 2017Applicant: Sharp Kabushiki KaishaInventor: Masafumi YASHIKI
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Publication number: 20160322004Abstract: A field sequential processing unit 11 includes a representative value calculating unit 111 configured to obtain a representative value for each pixel based on video data Ri, Gi, and Bi, a backlight data generating unit 112 configured to generate backlight data Xb indicating brightness of LEDs 18 in each area of the backlight 17 based on the obtained representative value, a video data correcting unit 113 configured to correct the video data Ri, Gi, and Bi based on the backlight data Xb, and a field data generating unit 114 configured to generate four pieces of field data Wf, Rf, Gf, and Bf based on the corrected video data Rc, Gc, Bc. By generating the backlight data based on the representative value for each pixel, it is possible to reduce a size of a circuit for obtaining brightness of the backlight for each area.Type: ApplicationFiled: September 4, 2014Publication date: November 3, 2016Applicant: SHARP KABUSHIKI KAISHAInventor: Masafumi YASHIKI
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Publication number: 20150371580Abstract: A display apparatus, and a driving method of driving the display apparatus control color breakup and prevent flicker. A backlight periodically emits a light beam by lighting one type of light source in a subframe period and a light beam by lighting all types of light sources in a subsequent subframe period. A lighting period for a cycle of emission of the same type of color light beams is shorter than a period for a cycle of receiving the video signal.Type: ApplicationFiled: October 7, 2013Publication date: December 24, 2015Inventors: Masafumi YASHIKI, Tomoyuki ISHIHARA, Masamitsu KOBAYASHI