Abstract: An improved testing system and method for testing a flat-panel display is disclosed herein. A display is positioned under a high resolution camera for detection of, for example, brightness uniformity across the display. Errors in the detected image due to aliasing are avoided in the present invention by incrementally shifting the displayed image relative to the camera and detecting the displayed image at various shifted positions. A resulting accurate display can then be reconstructed by identifying those detector pixels generating a maximum signal. A single image may then be reconstructed using only those detected maximum pixel signals. The reconstructed image will be free of aliasing. The reconstructed image may then be analyzed electronically, and any anomalies in the pixels forming the display panel can then be accurately detected.

Abstract: A method for inspecting a substrate having a plurality of output pixels using an image sensing device having a plurality of input pixels includes the steps of capturing an input image of a plurality of groups of output pixels with a plurality of groups of input pixels, each group of input pixels capturing a group of output pixels, each input pixel in a group of input pixels having a position, inhibiting modulation contributions from input pixels in the input image, forming a plurality of images from the plurality of groups of input pixels in the input image, each image including input pixels from a similar position in each group of input pixels, detecting defects in each of the plurality of images, and determining defects in sub-pixels of the substrate in response to the defects detected in each of the plurality of images.

Abstract: A method and resulting system for directing generally collimated illumination from a source at an oblique angle to a surface under inspection (SUS) to produce scattered nonspecular energy substantially normal to the SUS and for observing the scattered nonspecular energy in one of a plurality of fractional windows of a viewed image of the SUS via a plurality of focussing elements. Such arrangement results in simultaneous and significant throughput and sensitivity enhancement over existing art. The method can be enhanced further wherein the observing step is performed through suitable relative motion of the scattering image over the imaging plane to permit over sampling. Furthermore, the DMT is significantly simplified because imaging is utilized to electronically scan the wafer instead of using opto-mechanical scanning means. Imaging sensors with an aggregate 2000.times.2000 pixel resolution could image a 200 mm wafer to 100 microns pitch.

Abstract: The present invention provides an electro-optical element and its manufacturing method ideal for use in defect inspection devices for liquid crystal display substrates used in liquid crystal display panels. The electro-optical element of this invention possesses an electro-optical element, dielectric reflective film, transparent electrode, and transparent supporting substrate. These are united together by adhering the dielectric reflective film and transparent electrode edge to the electro-optical element. The electro-optical element is manufactured by consecutively affixing the transparent sheet with the transparent electrode, the electro-optical element, and transparent film with the dielectric reflective film to the transparent supporting substrate.

Abstract: An array of circuit elements which when excited produces voltages is analyzed by examining successive voltage images produced by the circuit elements. Specifically, the array of circuit elements is repeatedly excited at high speed while the voltage image produced by the array is electro-optically sampled at a succession of clock times using a relatively slow-speed electro-optic image sampling technique using a burst clock, thereby to capture a succession of voltage images. The successive voltage images can be viewed on a display device directly individually, or they can be processed by an image processor which compares the successive voltage images with stored representations of voltage images to yield information regarding the condition of the array. Maximum permissible device operating speed can also be determined without examination of individual cells.

Abstract: An elastic member is wrapped with wire or a wire mesh to provide uniform electrical contact with a substrate. The elastic member is compressible, allowing pressure to be applied, and a firmer contact established without damaging the contact points on the substrate.

Abstract: A method for testing liquid crystal display substrates with use of a testing apparatus which includes an electro-optical element. The test protocol includes applying a voltage between the circuitry on the liquid crystal display and the electro-optical element, irradiating the electro-optical element, evaluating performance under a variety of voltage conditions, and evaluating the corresponding response characteristics of the electro-optical element. The response characteristics are recorded by a plurality of CCD devices, each recording a different section of the panel. The changes in the magnitude of impressed voltage and polarity are synchronized with the recording timing. The recorded data is stored as frame memory which is subjected to frame by frame analysis to obtain quantitative information regarding the status of defective pixels.

Abstract: Construction defects in liquid crystal display base plates are detected by placing an electro-optical element, in which the optical properties change when an electric field is applied thereto, over and facing a liquid crystal display base plate, energizing the leads of said display base plate, irradiating the base plate with a light beam through the electro-optical element, and converting the optical changes detected for each pixel element electrode into a voltage distribution. The testing method in this invention is capable of identifying not only whether or not a pixel element electrode is functional, but also if a functional pixel element electrode is functioning as desired or not. Application of the testing method of this invention is able to test liquid crystal display base plates, including those which show ambiguous display irregularities. Electro-optical elements change their optical properties when an electrical field is applied thereto.

Abstract: LCD panels are inspected in-process to measure pixel decay, turn-on time and parasitic capacitance and/or identify pixel defects and line defects. Prior to final assembly, panels identified as having sufficiently few repairable defects are repaired. Line defects may be repaired. Further pixel defects may be repaired when redundant structures are included by splicing out the defective TFT or storage capacitor and splicing in a redundant, built-in TFT or storage capacitor. The inspection and repair systems are linked through a repair file. The inspection system identifies each defect by type and location and includes such information in the repair file. The repair system accesses such file and follows a prescribed repair method for a given type of defect at the location of such defect. The inspection system includes an automated non-contact voltage imaging system. The repair system includes lasers and means for repairing defects by adding metallization.

Abstract: The present invention provides an electro-optical element arranged to face a liquid crystal base plate, an electric source to impress an electric voltage between them, a source of light for irradiating light on the electro-optical element, a light detector to receive the reflected light from the electro-optical element, and a mounting device for fixing the liquid crystal base plate in a fixed position. The mounting device has a highly flat surface, groove thereon and vacuum attaches the liquid crystal base plate on the surface of the base platform. Light irradiates a reflective layer located on the lower surface of an electro-optical element which is in close proximity to the liquid crystal display base plate. A voltage is applied across the electro-optical element and the light reflected by the electro-optical element are measured. The optical characteristics of the electro-optical element is measured.

Abstract: A display panel testing apparatus, for observing large areas of a test panel, including an electro-optical element having optical properties that change to form images when an electric field is impressed thereon. The electro-optical element has a first surface facing a test panel that forms the electric field. The first surface and the test panel having a gap therebetween. The display panel testing apparatus also includes a light receptor for receiving the images from the electro-optical element and in particular a second surface of the electro-optical element. The display panel testing apparatus further includes a movable stage and movable mirrors coupled to the movable stage. The movable mirrors are adjustable to direct desired portions of the images onto the light receptor from desired positions of the electro-optical element. The movable stage also allows the movable mirrors to be positioned over the desired portions of the electro-optical element to receive the images portions therefrom.

Abstract: A testing method for active matrix liquid crystal display substrates having thin film transistors provided with a plurality of pixel electrodes, a plurality of source lines, and a plurality of gate lines formed on a substrate. A high resolution electro-optical element whose optical properties change when an electrical field is impressed on it is disposed above the active matrix liquid crystal display substrate and separated therefrom by an extremely small gap. Electric current is caused to flow between the pixel electrodes on the active matrix liquid crystal display substrate and the transparent thin film electrodes on the surface of the electro-optical element, creating an electrical field in the electro-optical element. By detecting local changes in the optical properties of the electro-optical element, defects in the pixels of the active matrix liquid crystal display substrate can be detected.

Abstract: An instrument for testing defects on active matrix liquid crystal display base plates used for liquid crystal display panels. The instrument includes a testing device having an electro-optical element and active matrix liquid crystal display base plate, a light source for emitting light to said base plate, a light guide for guiding light perpendicular to said electro-optical element, and a photo-receiver for receiving light reflected from the electro-optical element. The lighting device has a halogen light, a filter, and other elements, and the electro-optical element is equipped with an optically reflective part made of a dielectric multi-layer coating. The light guide has a translucent mirror incorporated inside a transparent vessel and is positioned at an angle with respect to the optical axis. The instrument can also detect various defects in active matrix liquid crystal display base plates with high accuracy.

Abstract: An array of circuit elements which when excited produces voltages is analyzed by examining successive voltage images produced by the circuit elements. Specifically, the array of circuit elements is repeatedly excited at high speed while the voltage image produced by the array is electro-optically sampled at a succession of clock times using a relatively slow-speed electro-optic image sampling technique using a burst clock, thereby to capture a succession of voltage images. The successive voltage images can be viewed on a display device directly individually, or they can be processed by an image processor which compares the successive voltage images with stored representations of voltage images to yield information regarding the condition of the array. Maximum permissible device operating speed can also be determined without examination of individual cells.

Abstract: An imaging method creates a two-dimensional image of a voltage distribution or a capacitance distribution of a substrate under test using an electro-optic modulator. A coarse modulator calibration determines the effect of non-uniformities in the modulator and determines a look-up table relating the gap distance between the modulator and the substrate to the intensity of the light emerging from the modulator. A positioning means calibration determines a look-up table relating control voltage to response by the positioning means. The modulator is moved over a portion of the substrate and then undergoes a positioning step, a fine onsite calibrating step, and a measuring step. The positioning step can be accomplished using the intensity of emerging light to determine modulator gap distance, and the response verses control voltage look-up table to determine a control signal to vertically position the modulator.

Abstract: A hierarchical testing method is implemented taking advantage of the nature of the most common defects in an LCD panel to achieve fast effective parametric testing of LCD panels and the like. At the first hierarchy of testing, the panel is logically divided into zones and each zone tested in isolation to identify zones having at least one defect. At the next hierarchy, electro-optic assisted zone inspection is performed to identify where within the zone the defects are located. Lastly, every pixel is inspected using a voltage imaging method to determine whether the switching integrity of the pixel is acceptable. The testing apparatus includes a plurality of panel interface devices coupling the panel under test's drive lines and gate lines to a precision measurement unit (PMU). A controller determines the PMU signals and configures the panel interface devices. The PMU monitors select drive lines and gate lines to isolate zones having defects.

Abstract: A hierarchical testing method is implemented taking advantage of the nature of the most common defects in an LCD panel to achieve fast effective parametric testing of LCD panels and the like. At the first hierarchy of testing, the panel is logically divided into zones and each zone tested in isolation to identify zones having at least one defect. At the next hierarchy, electro-optic assisted zone inspection is performed to identify where within the zone the defects are located. Lastly, every pixel is inspected using a voltage imaging method to determine whether the switching integrity of the pixel is acceptable. The testing apparatus includes a plurality of panel interface devices coupling the panel under test's drive lines and gate lines to a precision measurement unit (PMU). A controller determines the PMU signals and configures the panel interface devices. The PMU monitors select drive lines and gate lines to isolate zones having defects.

Abstract: LCD panels are inspected in-process to measure pixel decay, turn-on time and parasitic capacitance and/or identify pixel defects and line defects. Prior to final assembly, panels identified as having sufficiently few repairable defects are repaired. Line defects may be repaired. Further pixel defects may be repaired when redundant structures are included by splicing out the defective TFT or storage capacitor and splicing in a redundant, built-in TFT or storage capacitor. The inspection and repair systems are linked through a repair file. The inspection system identifies each defect by type and location and includes such information in the repair file. The repair system accesses such file and follows a prescribed repair method for a given type of defect at the location of such defect. The inspection system includes an automated non-contact voltage imaging system. The repair system includes lasers and means for repairing defects by adding metallization.

Abstract: An imaging method creates a two-dimensional image of a voltage distribution or a capacitance distribution across a surface of a substrate under test using an electro-optic modulator which is positioned and biased with respect to the surface of the substrate. The method involves a first coarse offsite calibrating step to compensate for nonuniformities in the light emerging from the modulator. Then, for each successive portion of the substrate over which the modulator is to detect characteristics of the substrate, the system undergoes a modulator relocating step, a modulator levelling step, a modulator gapping step, a fine onsite calibrating step, and a measuring step.

Abstract: An apparatus for testing a circuit board is provided employing a probe panel having a high density of photoelectrically addressable electrodes, each of the electrodes being coupled to a photoelectric switch connected to an outside source such as a voltage strip, and further employing photoelectric means for selectively activating each photoelectric switch as desired to apply test signals to selected locations of a circuit board. In one embodiment, a light panel having an array of pixels having a form factor scalably matching the electrode array is used to activate the photoelectric switches. A second embodiment uses a second probe panel on the circuit board side opposite the first probe panel. The desired light panel is a liquid crystal display panel using a laser diode as a light source.