Patents Assigned to Wintest Corporation
  • Patent number: 7199602
    Abstract: An inspection device for a display device includes: an inspection circuit which judges a defect of each of pixels based on current which flows through an inspection interconnect connected with interconnects of the display device; and an inspection driver circuit which drives by supplying a necessary signal to the display device. The inspection circuit includes: a correction circuit which generates a first correction current which substantially cancels a first current which flows through the inspection interconnect when all the pixels are set to an off-state based on the first current; a detection circuit which detects a measured value for each pixel obtained by correcting a measured current which flows through the inspection interconnect by the first correction current each time the pixels are sequentially set to an on-state; and a defect judgment circuit which judges a defect of each of the pixels based on the measured value.
    Type: Grant
    Filed: September 17, 2004
    Date of Patent: April 3, 2007
    Assignee: Wintest Corporation
    Inventors: Shoji Nara, Masatoshi Itoh, Makoto Ookuma, Wataru Yamamoto
  • Patent number: 7154261
    Abstract: A tester device including a tester section which includes a tester, an interconnection board receiving unit fixed on the tester section, and a light source. The interconnection board receiving unit has first and second interconnection boards electrically connected to the tester in the tester section, and a contact section electrically connecting the second interconnection board to an external probe. A cut section for an optical-path is provided in the second interconnection board. The interconnection board receiving unit supports the second interconnection board so as to provide the cut section at the side of the tester section. The light source is moved between an inspection position at which the light source faces the cut section in the second interconnection board and an escape position at which the light source does not face the second interconnection board.
    Type: Grant
    Filed: October 26, 2004
    Date of Patent: December 26, 2006
    Assignee: Wintest Corporation
    Inventors: Chisato Nagamine, Shigekatsu Maruyama
  • Publication number: 20060255827
    Abstract: An inspection device for a display device includes: an inspection circuit which judges a defect of each of pixels based on current which flows through an inspection interconnect connected with interconnects of the display device; and an inspection driver circuit which drives by supplying a necessary signal to the display device. The inspection circuit includes: a correction circuit which generates a first correction current which substantially cancels a first current which flows through the inspection interconnect when all the pixels are set to an off-state based on the first current; a detection circuit which detects a measured value for each pixel obtained by correcting a measured current which flows through the inspection interconnect by the first correction current each time the pixels are sequentially set to an on-state; and a defect judgment circuit which judges a defect of each of the pixels based on the measured value.
    Type: Application
    Filed: July 20, 2006
    Publication date: November 16, 2006
    Applicant: WINTEST CORPORATION
    Inventors: Shoji Nara, Masatoshi Itoh, Makoto Ookuma, Wataru Yamamoto
  • Patent number: 6891532
    Abstract: The present invention provides a picture element inspecting apparatus and method for an active matrix type display that is constituted by an LCD array device or an EL array device, which is capable of canceling the irregularities in source switches 13, the noise caused by device driving signals, and the irregularities in devices in the measurement apparatus, and enhancing the accuracy of a picture element inspection.
    Type: Grant
    Filed: April 22, 2002
    Date of Patent: May 10, 2005
    Assignee: Wintest Corporation
    Inventors: Shouji Nara, Masatoshi Itoh, Makoto Ookuma
  • Patent number: 6847223
    Abstract: An active matrix substrate has a plurality of pixel drive cells, each of which includes a switching element and a capacitor. The capacitor is charged and discharged through the switching element, and a charging current based on a charge stored in the capacitor and a discharge current after discharging the capacitor are sampled. The charging current is sampled at a plurality of points on a time axis in consideration of the variation of the on-resistance of the switching element. Since the load on a path through which an inspection current (charging current or discharge current) flows depends on the position of the pixel drive cells, the wave height value between the charging current and the discharge current is calculated for each pixel drive cell based on the discharge current, and whether or not the pixel drive cell has a defect is determined based on the wave height value.
    Type: Grant
    Filed: February 13, 2004
    Date of Patent: January 25, 2005
    Assignee: Wintest Corporation
    Inventors: Shoji Nara, Masatoshi Itoh, Makoto Ookuma
  • Patent number: 6815975
    Abstract: An inspection method and device are provided. The inspection method includes charging a parasitic capacitor between the gate and the drain of an operating transistor by supplying a potential from an inspection device, measuring discharge current from the parasitic capacitor by using the inspection device by discharging the parasitic capacitor, and determining whether or not a defect exists in each of a plurality of pixels by using the inspection device based on a value of the discharge current.
    Type: Grant
    Filed: May 20, 2003
    Date of Patent: November 9, 2004
    Assignee: Wintest Corporation
    Inventors: Shoji Nara, Hui Jiang, Wataru Yamamoto
  • Patent number: 6633135
    Abstract: It is an object of the present invention to provide an apparatus and method for evaluating an organic EL display, with which there is a simple drive circuit used for testing an organic EL display 10, evaluation of high reliability can be achieved, and an evaluation of the organic EL display 10 itself is performed prior to the installation of finished product drive circuits to the organic EL display 10, which makes it possible to suppress the decrease in yield caused by dealing with defective products due to the evaluation results.
    Type: Grant
    Filed: July 3, 2001
    Date of Patent: October 14, 2003
    Assignee: Wintest Corporation
    Inventors: Shouji Nara, Masatoshi Itoh, Makoto Ookuma, Tomoharu Innami
  • Publication number: 20020154108
    Abstract: The present invention provides a picture element inspecting apparatus and method for an active matrix type display that is constituted by an LCD array device or an EL array device, which is capable of canceling the irregularities in source switches 13, the noise caused by device driving signals, and the irregularities in devices in the measurement apparatus, and enhancing the accuracy of a picture element inspection.
    Type: Application
    Filed: April 22, 2002
    Publication date: October 24, 2002
    Applicant: Wintest Corporation
    Inventors: Shouji Nara, Masatoshi Itoh, Makoto Ookuma
  • Publication number: 20020047565
    Abstract: It is an object of the present invention to provide an apparatus and method for evaluating an organic EL display, with which there is a simple drive circuit used for testing an organic EL display 10, evaluation of high reliability can be achieved, and an evaluation of the organic EL display 10 itself is performed prior to the installation of finished product drive circuits to the organic EL display 10, which makes it possible to suppress the decrease in yield caused by dealing with defective products due to the evaluation results.
    Type: Application
    Filed: July 3, 2001
    Publication date: April 25, 2002
    Applicant: Wintest Corporation
    Inventors: Shouji Nara, Masatoshi Itoh, Makoto Ookuma, Tomoharu Innami