TW201017155A - Automatic dynamic pixel map correction and drive signal calibration - Google Patents

Abstract

To determine the pixel positions of a flat panel display, signals are applied to the gate lines and the data lines of the flat panel display without exciting the pixels. The gate lines and data lines have the same periodicity or pitch as the panel pixels but because the gate and data lines have narrower dimensions than the camera pixels, they provide sharper and more distinct signals. The intersections of the gate and data lines provide information about the position of the pixels. The pixel positions are subsequently used to generate a dynamic pixel map. Enhanced computational techniques use the pixel positions to determine the magnification of the imaging sensor head as well as the degree of rotation and offset of the panel pixel plane relative to the pixel plane of the imaging sensor head.

Description

201017155 VI. Description of the Invention: [Technical Field of the Invention] J. Cross-Reference Related Application The present invention claims to file the US Provisional Application No. 61/ entitled "Automatic Dynamic Pixel Map Correction And Drive Signal Calibration" on September 25, 2008. The benefits of No. 100241, all of which are incorporated herein by reference. BACKGROUND OF THE INVENTION The present invention relates to defect detection during manufacture of flat panel displays and, more particularly, during array fabrication steps of liquid crystal display panels.

C Λ* 奸 J During the manufacture of flat panel liquid crystal displays (LCDs), a large transparent plate of thin glass was used as a substrate for deposition of a thin film transistor (TFT) array. Generally, a plurality of individual TFT arrays are included in a glass substrate and are often referred to as TFT panels. In addition, an active matrix LCD (or AMLCD) covers a category in which a transistor or a diode is used for each pixel or sub-pixel, and thus such a glass substrate is also referred to as an AMLCD panel. Flat panel displays can also be fabricated using OLED technology, and although flat panel displays are typically fabricated from glass, they can also be fabricated from plastic or other substrates. The TFT pattern deposition is performed in a number of stages, in which a specific material such as a metal, indium tin oxide (ITO), crystalline germanium, amorphous germanium, etc. is deposited on top of the previous layer (or glass). , consistent with a predetermined pattern. Each stage typically includes multiple steps such as deposition, masking, etching, stripping, and the like. 201017155 At each stage of these phases and in the various steps in each phase, many manufacturing defects may affect the electrical and/or optical performance of the final LCD product. Referring to FIG. 1, such defects include, but are not limited to, metal protrusions 11〇 entering the ITO 112, ιτο protrusions 114 entering the metal 116, so-called mouse bites 118, opening circuits 120, transistors Short circuit 122 in 124, foreign particles 126, and residue 128 under the pixel. Amorphous germanium (a-Si) residues 128 at one pixel may result from underetching or lithography problems. Other defects include masking problems, over-etching, and the like. In a completed liquid crystal panel, a thin layer of liquid crystal (LC) material is placed between the two sheets of glass. A piece of glass contains the patterned two-dimensional TFT electrode array. Each electrode may be approximately 1 micron in size and may have a unique electrical voltage applied thereto by a drive circuit disposed along the edge of the panel. In a finished product, the electric field generated by each individual electrode is coupled to the LC material and modulates the amount of light emitted in the pixelated region. This effect produces a visible image on the finished panel as it is implemented throughout the entire two-dimensional array. Although the TFT patterning and deposition process is strictly controlled, the occurrence of defects in the @TFT array is still unavoidable. This limits product yield and adversely affects production costs. An important portion of the manufacturing cost associated with the LCD panel occurs when the LC material is injected between the upper glass sheet (generally carrying the color filter array) and the lower glass sheet (which carries the TF T array). Therefore, it is important to identify and correct any image quality issues prior to this manufacturing step. The problem of verifying the LCD panel before injecting the liquid crystal material is to check for images that are not visible without the LC material. Prior to deposition of LC material 4 201017155, the only signal that appears at a given pixel location is the electric field produced by the voltage on the electrode associated with that particular pixel (assuming no physical contact with the pixels) . To overcome this limitation, Photon Dynamics has developed an electro-optic inspection and test system, also known as an array tester or array checker (AC). The array tester can identify defects in the LC display by using a voltage imaging sensor (VIOS) as described in, for example, U.S. Patent Nos. 4,983,911, 5,097,201, and 5,124,635. The particular type is used to electrically drive the pixel electrodes to be tested within the panel as described, for example, in U.S. Patent Nos. 5,235,272 and 5,459,410. When the panel being tested is electrically driven, some of the pixel electrodes associated with the defect behave differently than the normal pixel electrodes. This difference can be detected using this voltage imaging sensor and associated image processing software. The type and location of many of these defects can be derived by using a combination of different drive patterns. 2 and 3A are perspective and front views of the camera 35 and the modulator 15 which are moved on a glass sheet 10 to detect defects thereon. Figure 3B is a front elevational view of one of camera 35 and modulator 15 configured to sense the electric fields from the pixel electrodes on the panel. As illustrated in Figures 3A through 3B, in order to test the patterned glass plate 1 'the imaging sensor head including a modulator 15 (developed by Photon Dynamics) on the tested panel to be tested (PUT) One of the regions 20 moves and then drops within a few microns from the surface of the panel. The pixel electrode arrays on the panel are electrically driven using a particular drive pattern. The small air gap 25 between the panel pixel electrodes 30 and the 201017155 of the modulator 15 allows an electric field from each of the driven pixel electrodes 30 on the patterned glass sheet 10 to be coupled to the modulator 15 to produce the A display (or voltage image) that is temporarily visible on one of the panels. This visible display is then captured by the camera 35 of the imaging sensor head to identify defects. After inspection of zone 20, modulator 15 is moved to another zone on the panel and the process is repeated. Through this step-and-repeat process, the entire PUT defect can be tested and tested. In Figs. 2B and 2C, the LC modulator 15 is shown to include an LC material 45 and a flat glass 50. A glass plate can be quite large (for example, a 7th generation sized plate is nearly two meters per side) and is therefore often divided into multiple panels. For example, the glass sheet 10 of Figure 2 is shown to include six panels 18. Conventionally, each panel contains a thin film transistor (TFT) array circuit required to drive a liquid crystal display. Testing of the panel is typically accomplished by observing the response of the TFT circuit to the applied drive voltage, particularly the pattern and sequence. Imaging the sensor head using one of the VIOS such as Photon Dynamics that detects the TFT response or the electric field on the pixel electrode using an electro-optical modulator, or detects the TFT response using an electron beam The AKT's sensor heads are used to observe and record these TFT responses. An imaging device such as a CCD camera (when using a VIOS) or a detector (when an electron beam is used) is used to record the observed response such as έ. As shown in Figure 2, an imaging sensor head is typically smaller than a test panel (PUT). In order to test all of the panels on the glass panel, the imaging sensor head must move with the panel, as described above, capturing images at each location. Photon Dynamics' VIOS system produces a voltage map (VM) image of the defects in the panel. The electrical waste 6 201017155 map identifies each of the detected defects within the coordinate space of the panel such that they can be easily repositioned by other systems such as the repair and inspection system. Figure 4 is a top plan view of the imaging sensor 35 disposed over an LCD panel 18. The LCD panel 18 is shown as being disposed along the plane defined by the X* board-Y "coordinate axis. The imaging sensor 35 is shown as being disposed along the plane defined by the X sensor-Y*« coordinate axis. In order to determine the position of one of the planes relative to the other plane, three degrees of freedom are required, such as (□) a known LCD pixel (such as pixel 70) and a known imaging sensor pixel ( The X and γ offset between pixels 60), and (□) the angle of rotation α between the imaging sensor and the XY axis of the LCD panel. Figure 5 shows the use as is conventional in the prior art. A control and data flow between various components of a system for generating a voltage map. A pattern generator 100 provides a drive pattern to the PUT. Thereafter, a VIOS 102 uses its CCD camera to generate a voltage image of the PUT. The generated voltage image includes a measurement image and a calibration image. At the beginning of a board test, a mechanical pixel map (MPM), optical correction data, and alignment information are supplied to a computer, and the computer generates a response as a response. Dynamic pixel map 1〇6. The MpM is from the °H panel The alignment marks and geometric information of the board are obtained. The dynamic pixel map (DPM) together with the measurement image and the calibration image are then used by an image processing computer 1 to generate the voltage map. FIG. 6A is A top view of one of the panels 15A, as is known in the prior art, includes 150 panel alignment marks 152 and 162 disposed at opposite diagonal angles of the panel. Use coupling to the spacer 2〇 The signal lines of 〇, 2〇2, 2〇4, and 201017155 206 activate the pixels in the active display area 160. The panel cut line 156 is also shown in Figure 6. The geometric information of the LCD pixel electrodes includes the pixel size and the pitch of the pixel array along X and γ and their positional relationship with respect to the alignment marks. FIG. 6B is an enlarged view of the area 17 of the active display area 160. The view 'is shown to include eight pixels at the intersection of columns 172, 174 and rows 182, 184, 186, 188. For each panel, the test system measures the relative position and orientation of the alignment marks and then Calculate the χ, γ of the panel Position and rotation. The typical accuracy of this system technology is approximately 2 μm, while a typical LCD pixel electrode is approximately 1 μm to 3 μm wide. Optical correction data is accumulated during installation of the system. Optical-like correction data includes, for example, '□' the rotation and position of the imaging camera relative to the entire imaging sensor head, (□) the imaging sensor head relative to its Χ-Υ direction in the test system The initial position and rotation of the travel, (□) other optical information, such as distortion, and (□) phase error. Use this information to generate a dpm. The DPM provides a virtual coordinate that guides the ac to find the center of each LCD pixel electrode. The system whereby the VM image is capable of representing true voltage information. The VM image can undergo additional image processing to determine the exact nature of the defects. Therefore, the accuracy of the DPM affects the voltage values, and thereby also affects the defect detection performance. Typically, a DPM must be accurate to within 1 to 10 pixel electrode dimensions, such as within 100 microns to 1 〇 microns. Conventional DPM processing sequences, such as shown in Figure 5, do not allow automatic incorporation of positional data from the measurement or image capture of the LCD pixel array itself. For example, in a conventional method, the 8 201017155 user manually adjusts an ideal DPM grid to match a voltage image of the LCD pixel electrode array. This method is tedious and time consuming because it is repeated for each board being tested. Often, due to time constraints, this method is used to reuse the generated pattern for subsequent boards, although such prior results may not apply. Accuracy is also dependent on the consistency and judgment of the user. For some LCD panel configurations, providing sufficient signal contrast between adjacent LCD pixels is easier to implement than others. The conventional checkerboard pattern may be suitable for a 2G2D panel 150 (see Figure 6A), which includes two gate inputs for driving two separates ("gates (" Gate even)', GE 200 and "gate odd", 'GO 202) and two separate data inputs ("data even" 'DE 204 and 'data odd' DO 206) A shorting bar. After the array is tested and processed and assembled into the final flat panel display product, the panel is cut along the panel cut line 156 to remove the shorting bar pattern and alignment marks. Figure 7 is a A top view of a 1G1D panel 180, the data (1G1D) panel 180 includes a single shorting bar for driving the gate 208 and a single shorting bar for driving the data input line 210. Other patterns Such as 1G2D is also possible.

Section 8A shows the voltage signals applied to a 2G2D panel such as panel 150 shown in Figure 6A to produce a checkerboard pattern. Figure 8B shows a comparison of the responses of adjacent pixels to the board drive signals of Figure 8A. Since in a 2G2D panel, two independent data drive signals and two independent gate drive signals drive alternate columns and rows of the array, a data/gate pair (eg, GO 202 and DO 204) is compared to the second data/ The gate pair (ge 200 and DE 9 201017155 206) can be driven in a different pattern and sequence. More specifically, the odd columns and rows can be driven and all of the even columns and rows are driven low. For example, an LCD pixel electrode can be positively charged and its adjacent LCD pixel electrodes in the X and gamma directions are negatively charged; each of the negatively charged pixels is likewise surrounded by positively charged pixels in the X and gamma directions. Thus, a peak average voltage for each imaging sensor location can be calculated from the CCd voltage image, thereby providing a result for adjusting the DPM. Therefore, in a checkerboard pattern, adjacent LCD pixel electrodes can be distinguished from each other in the X and γ directions. One of the disadvantages of this method is that it is limited to certain types of LCd panels, and (□) requires the expected accuracy and requires a large amount of data samples and/or additional signals.

The noise filtering algorithm takes more time. Fig. 8C shows the voltages received by the pixels of Fig. 8B in the XX direction or the γγ direction. The figure shows that the associated camera pixels of the responses of the panel pixels of Figure 8C are not recorded. Figure 8E shows the output signals of the camera pixels of the first map. The net signal may not be as clear as the signal shown in pages 88 to _ due to various factors that may cause signal drop, but it is still readable. The s pixel electrode has a relatively sharp physical boundary, and the money circuit phase (4) (9) surrounding the pixels has a large _ the same or a smaller _). The distance between the phases is also short, tens of microns. Such a short distance can cause the equal power == circuit in the pixel. The charge of the pixel electrode at the edge of the electrode is also a local (four) field effect, which can (4) the distribution of the charge in the adjacent electrode of the material, thus causing an inconsistent distribution of the signal of the 201017155 signal. The single gate and data drive input of a 1G1D panel, such as panel 180 of Figure 7, causes all of the LCD pixel electrodes to respond in the same manner. Figure 9A shows the gate and data voltage signals applied to a 1G1D panel. Figure 9B shows a comparison of the responses of the pixels to the driving signals of Figure 9A. As can be seen from Figure 9B, the pixels cannot be easily distinguished from one another. Figure 9C shows the voltages received by the pixels of Figure 9B along the equal or gamma gamma directions. Figure 9D shows the associated camera pixels recording the responses of the panel pixels of Figure 9C. The signal of one LCD pixel electrode and another LCD pixel electrode is virtually indistinguishable due to various factors that can cause degradation of the signals. Although an image or measurement of the LCD pixel electrode provides a more reliable value for the rotation parameter than the alignment mark of the plate or panel, the information from the LCD pixel array The accuracy is affected by whether the resolution of the image or measurement allows the LcD pixel electrodes to be distinguished from one another. The resolution of the image or measurement is determined by a number of factors. The first is an optics that aligns the system. The second is the signal contrast between adjacent LCD pixel electrodes. The third is the distortion of the signal across the ends of a given pixel electrode and between the pixel electrodes due to imperfect material and/or electrical effects. The fourth is due to an imperfect alignment system traversing - the degradation of the signal at both ends of the given pixel electrode and the pixel electrode. The resolution of the image or measurement is strongly dependent on the LCD pixel electrodes and the camera CCD pixels and any optics present between the camera and the LCD pixel electrodes. The CCD pixel typically has a size of approximately 10 to 15 microns in 201017155 and its projected image is approximately 3 to 4 microns in size. An LCD pixel electrode is typically about 121 microns X and about 363 microns in size. Therefore, if the optical devices are well aligned, it is easy to distinguish the LCD pixel electrodes from each other with the camera and its optics. However, because the LCD and camera pixel electrodes are regular arrays and because the two arrays have different pitch or period 'moir0' (or interference) patterns, especially when the respective arrays are The spacings are not integers relative to each other. In addition, a slight rotation of one array relative to the other produces an interference fringe. This results in inconsistent signal strength of the LCD pixel electrodes within the array. One challenge in inspection and testing is to determine the position of the L C D pixel electrodes relative to the digital camera of the sensor such that the captured visible display or voltage image can be further processed to capture defect information. Once the images are processed and the defects are detected, the mapping information between the LCD pixel electrodes and the defects can be used to identify locations of the defects for further use in other systems such as viewing or repair systems. use. The detailed defect information from these voltage images requires accurate knowledge of the position of the LCD pixel electrodes. Furthermore, determining the position of the LCD pixel electrode requires correlating or mapping the camera array of the imaging sensor head with a reference position entity on the imaging sensor head, and then the location of the sensor head with the panel A position related or phase map on. Typically 'the imaging camera of the system is mapped to the entire sensor head as part of the calibration procedure of the system, the calibration procedure of the system is completed during initial installation and is checked afterwards, for example every few months One 12 201017155 times. However, determining the position of the sensor head relative to the board must be done before testing each board. In addition, a typical TFT pixel electrode is approximately 1 〇〇 micrometer x 300 micrometers. Therefore, the accuracy of the position of the LCD pixel must be measured within, for example, 10 to 1 GG μm. In the case of mass production of many products, commercial suppliers of flat panel displays increasingly require high throughput and fast time. Therefore, the time required to align or calibrate one side panel should ideally be kept short.

The invention relates to the method of measuring the position of the flat panel display relative to the position of the sensing head. According to the invention, the method includes the following steps, and the signal is applied to the _ to Forming a plurality of gate lines of the pixels on the panel, capturing the response of the gate lines to the first signal, and applying a second signal to the plurality of data formed on the panel On the line, the data lines are retrieved in response to the second signal, and the first and second responses are combined to generate a combined response, and the combined response is used to determine that the gate lines intersect the data. The intersection of materials indicates the location of the pixels. In some implementations, the method further includes using the pixel locations to determine the offset and rotation values of the panel display (4) relative to the domain. A device operable to determine the pixel location of a flat panel display, in accordance with an embodiment of the invention, includes, in part, a signal generator, a sensor head, and a computer system. The signal generator is operative to supply a signal to a plurality of gate lines and data lines of the pixels formed on the panel, 13 201017155 a sensor head operable to capture the gates and data line pairs The response of the first signal and a computer system. The computer systems have a combination of the responses of the gates and data lines to produce a combined response module, and the combined response is used to determine the one of the intersections of the gate lines and the data lines. The intersections represent the locations of the pixels. In some embodiments, the apparatus further includes a module that uses the pixel locations to determine the offset and rotation values of the flat panel display relative to the sensing head. A method of identifying such locations of pixels formed in a plurality of panels of a flat panel display, in accordance with an embodiment of the invention, comprising, in part, the step of supplying a voltage to one of the panels to cause Pixels disposed on at least one edge of the edges of the panel exhibit an image contrast that is different from the image of a subset of the remaining pixels that are not disposed along the edge of the panel, and use the image contrast between The difference is to identify the location of the pixels of the panel. A device operable to identify such locations of pixels formed on one or more panels of a flat panel display, in accordance with an embodiment of the invention, partially including a signal generator, a sensing head, and a computer system. The signal generator supplies a voltage signal to at least one of the panels. The sensor head captures one or more voltage images of the pixels disposed on the panel. The captured voltage images exhibit a first contrast associated with pixels disposed along at least one edge of the edges of the panel. The captured voltage images exhibit a second comparison with the remaining pixels of the panel. The computer system uses the difference between the first and second contrasts to identify the locations of the pixels of the panel. 201017155 Brief Description of the Drawings Figure 1 shows a number of exemplary defects on a plate as is conventional in the prior art. Figure 2 shows an exemplary camera and an exemplary modulator that are moved on a patterned glass plate to detect defects as is conventional in the prior art. Figure 3A is a front elevational view of the exemplary camera and exemplary modulator moving on the patterned glass sheet of Figure 2.

Fig. 3B shows the exemplary camera and exemplary floating modulator of Fig. 2 disposed adjacent to the patterned glass sheet to detect defects. Figure 4 is a top plan view of one of the imaging sensors disposed above the -LCD panel. Figure 5 shows the control and data flow between the various components of a system for generating a voltage map as is conventional in the prior art. Figure 6A shows an exemplary panel including a TFT array, panel reference marks, and a 2G2D shorting bar for testing the array. The first side is an enlarged view of the area of the panel of Figure 6A. Figure 7 shows an exemplary panel including a -TFT array, panel reference marks, and a 1G1D shorting bar used to test the array. Figure 8 shows an exemplary voltage applied to the 2G2D panel of Figure 6A as previously known in the art to produce a checkerboard pattern. = shows the checkerboard pattern voltage diagram of the μ pixel electrode due to the application of the exemplary voltage shown in Fig. 8A. The exemplary voltages received by the pixels of Fig. 8 are shown along the XX or γ gamma side 8C. 15 201017155 Figure 8D shows the associated camera pixels recording the responses of the panel pixels of Figure 8C. Figure 8E shows the output signals of the camera pixels of Figure 8D. Fig. 9A shows an exemplary voltage applied to the 1G1D panel shown in Fig. 7 as is conventional in the prior art. Fig. 9B is a spatial voltage diagram of the pixel electrodes generated by applying the exemplary voltage shown in Fig. 9A. Figure 9C shows the voltages received by the pixels of Figure 9B along the XX or YY directions. Figure 9D shows the associated camera pixels recording the responses of the panel pixels of Figure 9C. Figure 9E shows an exemplary output signal for the camera pixels of Figure 9D. Figure 10A is an exemplary timing diagram of one of the signals suitable for determining the locations of the pixels of a flat panel display in accordance with an exemplary embodiment of the present invention. 10B through 10G are exemplary images of the gate lines and data lines receiving the voltages shown in FIG. 10A in accordance with an embodiment of the present invention. Figure 11A is a screenshot of a portion of a slab that uses a voltage signal to drive data and gate lines in accordance with an exemplary embodiment of the present invention. Figures 11B and 11C are the intensity profiles of the image taken along the X and Y directions of Figure 11A. Figures 12A through 12C show an exemplary process for determining the offset between a flat plane and a camera plane using 201017155 in accordance with an exemplary embodiment of the present invention. Figures 13A through 13D show an exemplary process for determining the angle of rotation between a plane of a flat panel and a plane of a camera in accordance with an exemplary embodiment of the present invention. Fig. 14 is a view showing the flow of control and data for various components of a system for generating a voltage map according to a first embodiment of the present invention. Figure 15 shows an image processing computer 600 in accordance with an embodiment of the present invention. [Embodiment] j Detailed Description of the Invention ★ According to the present invention - the position of the pixel formed on the flat plate is used to detect a defect on the flat plate such as a coordinate head of a sensor head of a camera The towel was measured relatively quickly. In order to locate the pixel locations, the pixels that are designed to be matte-finished are sharper and clearer (or, more specifically, the locations of the _ characteristic points in the pixel, such as their centers or corners). One of the signals is applied to the surface of the signal drive pattern

The board ^, regardless of the panel type, may be -2G2D, 1G1D or gossip thereafter, and the positional information about the flat pixel electrodes is extracted and plotted in the coordinate space of the pixels of the camera. The profit and rotation of these LCD pixels relative to the parallel pixels are automated to improve the TACT time. The missing pixels and the pixel locations of the panel from the panel captured using the image captured by the sensor head are then transported to other systems, such as a viewing or repair system. 17 201017155 Next, it is to be understood that the term panel pixel electrode and LCD pixel (or LCD pixel electrode) are used interchangeably to refer to the TFT electrode circuit being formed on the 忒 panel. It will also be understood that the terms imaging sensor pixel, camera pixel or CCD pixel are also interchangeable and refer to the portion of the imaging sensor (also referred to as a camera) array that captures images of the panel pixels. In addition, it is to be understood that an LCD space is defined by the pixel electrode coordinates of the LCD and a CCD space is defined by the CCD coordinates of an associated camera. It is further understood that embodiments of the present invention are equally applicable to camera sensors including other sensor arrays such as the CM〇S4 analog when the following description is provided with reference to a CCD camera or CCD pixel. In accordance with an embodiment of the invention, the signal driven pattern is applied to the gate lines and the data lines without exciting the pixels. The gates and data lines have the same period or spacing as the panel pixels, but because the gates and data lines have a narrower size than the camera pixels, they provide sharp and sharper signals. The intersection of the gates and the data lines provides information about the location of the pixels. These pixel locations are then used to generate a dynamic pixel map (Dpm). Figure 10A shows a drive pattern of a gate and data line applied to a panel in accordance with an exemplary embodiment of the present invention. The timing of the various drive voltages is associated with the camera's image record at a selected frame rate. As shown in Fig. 10A, the data lines are driven to a positive voltage during the period of the graph and the gate lines are maintained at the ground potential. The camera is triggered and the __ image is recorded before the expiration of the frame period, as shown in the figure. 18 201017155 The five-dot line in Fig. 10E shows five exemplary data lines that receive the voltage pattern shown in Fig. 10A. During frame 2, the data lines are supplied with a ground potential and the gate lines are driven with a non-zero voltage. The camera is triggered and another image is recorded before the expiration of frame 2 and after the drive voltage has been charged to the data lines, as shown in Figure 10C. The two-dot line in Fig. 10F shows two exemplary gate lines that receive the voltage pattern shown in Fig. 10A. The gates and data driven patterns can be repeated multiple times to collect images similar to those shown in Figures 10B and 10C. The results are then combined to form a combined image, as shown in Figure 10D. Figure 10G shows the ten intersections of the data and the gate lines of Figures 10E and 10F. The ten intersections define the locations of the corners of the LCD pixels (or alternatively they can be used to determine the center of the L C D pixels). Other gate/data line drive patterns may be used that may have different orders between the drivers of the gates and the data lines, different timings between the gates and the drivers of the data lines, or different voltages. In other embodiments, the gates and data lines can be driven simultaneously as long as the pixels are not charged (excited). Moreover, the combined image displayed in Figure 10D can be produced in a number of different ways. For example, in one embodiment, a plurality of data lines and gate lines are independently driven to enable their associated images to be captured and processed. Thereafter, their images are combined to locate their intersections. In another embodiment, an image of the data lines is combined with an image of the ones to locate their intersection. Figure 11A is a diagram of a portion of a plate having a voltage signal driven by a voltage signal and a gate line according to an exemplary embodiment of the present invention. Figure 19 and Figure 11C is the image of Figure 11A. The intensity curves taken in the x direction (bedding line) and the gamma direction (gate line). The maximum value of the period in Figure C represents the position of the data lines and the gates, respectively. The intersection of the body and the brake line can be identified by the location of the intensity maximum along the line in a combined digital image, since t is the sum of the data and the gate signal. - because the data and gate width are smaller than the pixel width of the cameras, a significant portion of the threshold is distributed in a single camera pixel, and any potential change due to the Moire effect is relatively easy to distinguish. Because the gates and data lines have a smaller overall cross-section and are separated from each other than the panel pixel electrodes, they have a lower charge reach and a reduced electric field interference effect. Therefore, the fringe field effect due to the concentrated charge is significantly weakened in accordance with the f embodiment of the present invention. In accordance with another embodiment of the present invention, an enhanced computing technique uses the panel pixel locations to allow for determining the magnification of the imaging sensor head (by comparing the spacing measured by the imaging sensing || with the panel) Geometric specification) Ο and the rotation and offset of the panel pixel plane relative to the camera pixel plane. Alternatively, the panel pixel locations as described above or using any other technique (e.g., a checkerboard or instant drive patterning) can be used to correct for phase errors, errors due to optics, and the like. This in turn allows for relaxation of the requirements for these stages and optics. Figure 12A shows the LCD panel 3 of one of the pixels 302, 3022, 3023 having a number of exemplary chevronTM shapes. The positions of the pixels 302, 3022, 3〇23 20 201017155 are used to determine the panel 300 and an imaging camera. The offset and rotation between the χγ planes. A template of one of the repeating features of the panel, such as its pixels, is captured from an image of a single point. A point is understood to mean the area of the panel whose image can be captured by an imaging camera in a single shot. An LCD pixel such as one of the pixels 3〇1 located at, for example, one of the corners of the panel (e.g., the imaging camera is initially scanned) is selected as a reference pixel. The expected position of a corresponding camera pixel 312 is also shown in Figure 12A. Next, one of the repeating LCD pixel electrodes image templates 350 is constructed as shown in Fig. 12B. Each square in Figure 12b represents a camera pixel. The position of the camera pixel 3122 is displayed in Fig. 12B using a one-line square. Next, the template 35() is set at its intended position (based on the position of the reference pixel) to calculate S between the actual position of the template and its intended position. Thereafter, the template is shifted in a systematic manner until a condition is met. This condition may be satisfied when, for example, the difference between the actual position of the template and its intended position meets the minimum defined by a threshold. This can be found in the same way as the smallest difference. For example, the template may be shifted by a fixed step in four directions from the starting point or it may be used to seek to make the money converge to - (5), the value of the calculated mosquito increments and directions to move, and the like. It is to be understood that any other pixel shape can be used and any other (four) (four) can be used as the reference pixel electrode. The difference between the actual position of the template and its expected position (corresponding to the difference between the actual position 312 of the camera pixel and the expected position 3122, as shown in the figure), when such a condition is satisfied The offset of the LCD from the camera in the χ γ plane is referenced to the figure, and the position of the reference LCD pixel electrode is often known to be within half (50 to 100 microns, typically) of at least one LCD pixel size. In accordance with an embodiment of the present invention, when two-dimensional interpolation is used, the XY offset can be determined to be within a pixel size of a camera or less. In accordance with other embodiments of the present invention, to determine the offset, a plurality of sub-regions, e.g., five, are selected from a single point on the panel. The average deviation between the measured positions of the pixels in the selected regions and the expected positions is then used to determine the offset.

Figures 13A through 13D schematically illustrate one method for determining the angle of rotation between the LCD panel and the imaging array of the camera in accordance with another exemplary embodiment of the present invention. For this offset measurement, the method uses a repeating pattern of the LCD pixel array. To determine this rotation, an Lcd image site 400 is taken, as shown in Figure 13A. Next, choose something like this

One of the sub-regions of the sub-region 402 of the shadowing site is used as a reference point. The sub-region may be located, for example, at the corner of the image of the site and spanning the region of the camera pixel of 100 pixels (four) pixels wide. As shown in Fig. 13C, one of the images of the reference sub-area is placed in a small lateral direction (e.g., along the parent axis of the camera) at a position where the image is to be repeated. Figure 13C also shows the panel and the ccd camera: the χ-γ coordinates. Thereafter, the difference between the reference sub-region 2 and the sub-region is calculated; like 4〇4 between its expected positions. Thereafter, the reference sub-area is shifted in the direction of the lateral movement direction by 9 degrees (for example, along the camera_system-by-system mode until the condition is satisfied). When, for example, the difference is defined by a threshold value This condition is satisfied when the minimum value is satisfied. It is shown in Fig. 13 as "the position of the job rotation angle from the generation-minimum value [22 201017155 the final position of the domain image 404, the reference image 4〇2 The initial position and the expected position of the reference image 404 are defined. The accuracy of the rotation angle as described in the method herein is partly due to the distance between the two sub-regions, the size of the sub-region, and the interpolation resolution. In one example, an accuracy of about 0.055 arc minutes or 2 microns can be achieved. The minimum difference can be found in any of a variety of ways. For example, the reference image can be moved from a starting point in, for example, four. Fixed steps of directions or they may be moved in increments or directions determined by calculations that seek to converge the difference to a minimum, etc. It will be appreciated that the reference sub-regions may have different The size and location are at different locations. Figure 14 shows a flow of control and data between various components of a system 500 for generating a voltage map in accordance with an exemplary embodiment of the present invention. A pattern generator 400 A pixel drive pattern and a line drive pattern are provided to the party test panel. Thereafter, a VIOS uses a camera that can be a CCD camera or other camera to generate a voltage image, a calibration image, and a measurement image of the test panel. An image processing computer 5〇6 uses this data to determine the pixel position of the panel and the offset and rotation of the panel relative to the image plane of the camera in the XY plane. A dynamic pixel map generator 508 is self-image processing. The computer receives the information and calculates a mechanical pixmap (MPM), optical correction data, and alignment information in response. The image processing computer 506 receives the calculated mechanical pixmap (MPM), optical from the dynamic pixmap generator 508. Correcting the data and aligning the information to generate a voltage map. The time to calculate the offset and rotation using the image depends on the quality of the signal contrast of the initial image. Since an LCD panel includes a repeating array, the any-axis enhancement algorithm of 23 201017155 can be applied. For readings with low l-to-tb, a pure complex (four) algorithm or continuous application may be required. Algorithm. Parent cross-correlation algorithm, absolute difference sum and (sum of absolute method or other similar algorithm to determine the bias η - comparison ° conventionally, the cross-correlation is two images he ten / 2 (x, y) A measure of the similarity, as defined below: n_1 v σ, σ2 #2, 〇^ and port 2 are the changes between the two shadows '1 and 1. For example, "is the pixel in each image The number, and the average and standard deviation of the image, the parameter r can be the same in both images, then r = l.

Referring to Fig. 13C, if the distance between the two sub-regions of * is a plurality of LCD pixel sizes, when there is no rotation, the interaction between the two sub-regions is a maximum. If there is a rotation, the peak cross-correlation will move to a new location for the sub-region image 404. Therefore, the angle of rotation can be detected by looking for the offset of the sub-area image 404. If cross-correlation is used to determine the offset and rotation instead of finding the maximum point, then the maximum point is searched. Performing interaction correlations can be time consuming. According to another embodiment, an image comparison for determining the offset or rotation can be achieved using the absolute difference sum (SAD) as defined below: ^^=^\I,(x,y)-I2(x,y)\ Xy Conventionally, a SAD can vary between 0 and infinity. The more similar the two images are, the smaller the SAD value is. If the two images are the same '5^D==〇. Referring to Fig. 13D, 24 201017155, the rotation error can be detected by finding the minimum SAD position of the sub-area 404. The SAD algorithm is faster but less accurate than the cross-correlation algorithm. Figure 15 shows an image processing computer 600 for use in accordance with an embodiment of the present invention. The image processing computer 600 is shown to include at least one processor 〇2 that communicates with a plurality of peripheral devices via a busbar subsystem 〇4. 14 peripheral devices may include a storage subsystem 6〇6 (partially including a memory subsystem 608 and a file storage sub-function 61 ()), user interface input

The device 612, the user interface output device 614, and a network interface subsystem 616. These input and output devices allow (4) to interact with the data processing system. The "face subsystem 616 provides an interface to other computer systems, networks, and health resources 604. Such networks may include the Internet, - Regional Network = AN), a wide area network (side), a wireless network, - an internal network, a network, a public network, a network, or Any other suitable network interface subsystem 616 acts as a means for receiving data from other computers that are transmitted from the computer (the poor material processing device). The embodiment of the network interface subsystem 616 includes an _Ethernet data machine (telephone, satellite, electric line, single line, etc.), and the (asynchronous) digital user interface input device 612 can include a keyboard, Such as a heart = track ball, touchpad pointing device, a shape input panel, factory, :, a touch screen incorporated into the display, such as sound: =, - microphone sound recording ^ ^ recognition system, using the technology , two types of input devices. In general, the "input device is intended to include all of the possible types of devices and methods for inputting information to the processing device. The user interface input 614 may include a display, a printer, a fax machine, or the like. Non-visual display of the audio output device. The display subsystem can be a cathode ray tube (CRT), such as a liquid crystal display (lcd): a flat panel device or a drop device. The term output device is generally used to include all of the ways in which information is rotated from the processing device.

The storage subsystem 6 can provide basic programming and data construction of the functionality in accordance with an embodiment of the present invention. For example, in accordance with an embodiment of the present invention, a software module implementing the functionality of the present invention can be stored in a storage subsystem. These software modules can be executed by the processing secret 2. The storage subsystem 606 can also provide a repository for storing the information used in accordance with the present invention. The storage subsystem can be packaged as a memory subsystem 608 and a file/disk storage system 61.

The memory subsystem 608 can include a plurality of memories, including pointer data for storing the program execution period Fa', a line machine # memory (RAM) 618, and a read-only memory (R〇M). ) 62〇. The broadcast storage system provides a long-term (non-electrical storage) for the materials and resources (4) and can include - a hard disk drive, a floppy disk drive and associated removable media, a CD-ROM only Read memory (CD_R〇M) drivers, an optical drive, removable media, and other similar storage media. The busbar subsystem 〇4 provides a mechanism for enabling the various components and subsystems of the processing device to communicate with each other. Although the busbar system is a single-bus bar, the alternative embodiment of the busbar subsystem 26 201017155 can use multiple busbars. The processing device can be of a different type including a personal computer, a portable computer, a workstation, a network computer, a mainframe, a kiosk or any other data processing system. It is to be understood that the description of the computer system 600 is only an example. Many other configurations with more or less than the system shown in Figure 15 are possible. Embodiments of the present invention provide a number of advantages. First, as discussed above, the higher contrast between the gate/data line and the surrounding pixel regions enables the measurement of the offset and rotation between the panel and the camera to be more accurate than conventional techniques. Secondly, since the gate lines, data lines, and their intersections have the same period or spacing as the panel pixel electrodes, the voltage images of the lines can be used for higher accuracy than the prior art. The position and period of the pixel electrodes of the panel are measured, and the positions of the center of the pixel electrodes of the panel are measured. Third, the comparison of the pixel pitch measured by the imaging sensor head to the geometry of the panel provides one measure of the optical magnification of the imaging sensor head. This in turn allows for relaxation of the sensor head optics requirements. According to another embodiment of the invention, the edge of the panel is detected. To accomplish this, all of the LCD pixels in the panel are charged at a voltage such that the outermost perimeter of the panel and the active area of the panel itself (see, for example, Figures 6A, 6B, and 7) There is a high contrast between them. Driving the panel in such a manner enables a sharp outline of the edges of the panel (i.e., the boundaries of the active region). The use of an image processing algorithm and the mechanical pixel map' can be used to determine the position of the pixel center using such an embodiment when a board pattern cannot be used (e.g., a 1G1D panel). In such embodiments, a probe frame provides the drive voltages to the contact pads, the contact pads being disposed adjacent to the active region. If the entire active area is not visible on one side of the panel, then the remaining edges of the panel can be used to determine the pixmap. Although the above description has been made with reference to an electro-optic test method using a VIOS technique, embodiments of the present invention are equally applicable to the measurement of a TFT array using an electron beam technique requiring a complicated and expensive calibration plate. Additionally, embodiments of the present invention can be used for voltage sensitivity calibration in electron beam testers, VIOS testers, etc., as the data and gate signals vary linearly as a function of the applied voltage. Since the voltage images obtained in response to the application of a voltage to the gates and data lines typically have good signal contrast in accordance with the present invention, the mapping process can be fast enough and can be based on each panel. Applyed without significant degradation of total TACT time. In accordance with conventional methods, the mapping process is performed at most per-plate and is typically performed less. In contrast, embodiments of the present invention provide automatic dynamic adjustment in mapping. In other words, embodiments of the present invention are - Multiple adjustments occur within the board. The conventional method requires about 4 to 5 seconds to complete the offset and rotation and the final DpM calculation, and the embodiment of the present month can perform a more accurate calculation in, for example, -second or less than seconds. The above embodiments of this month are illustrative and not limiting. Various alternatives, equivalents are possible. In view of the present disclosure, other additions are made within the scope of the patent claims that are reduced or repaired and intended to be attached. 28 201017155 I: Schematic description of the drawings 3 "The figure shows a number of exemplary defects on the plate as is known in the prior art. ' Figure 2 shows a patterned glass plate as conventionally known in the prior art. An exemplary camera and an exemplary modulator that move up to detect defects. Figure 3A is a front view of the exemplary camera and exemplary modulator moving on the patterned glass plate of Figure 2. Figure 3B The exemplary camera and the exemplary floating modulator disposed near the patterned glass plate to detect defects are shown in Fig. 4. Fig. 4 is a top view of one of the imaging sensors disposed on the -LCD panel. Figure 5 shows the control and data flow between the various components of a system for generating a voltage map as is conventional in the prior art. ▲ Figure 6A shows the inclusion of a -TFT array, panel marks, and Try one of the 2G2D shorting bars of the array to demonstrate the panel. Figure 6B is a 7th image of the panel of Figure 6A showing a 1G1D shorting bar including a TFT array, a panel reference, and a wire test array. One of the demonstration panels. An exemplary voltage applied to the & G2D panel as shown in the prior art to produce a checkerboard pattern is shown in FIG. 8A. FIG. 8D shows the panel pixels of the 8Cth image. The associated camera pixels of the response. Figure 8E shows the output signals of the camera pixels of Figure 8D. Figure 9A shows the application of Figure 7 as shown in the prior art. The exemplary voltage of the 1G1D panel. Figure 9B is a spatial voltage diagram of the pixel electrodes generated by applying the exemplary voltage shown in Figure 9A. Figure 9C shows the pixels along the 9B diagram along the same The voltages received in the XX or YY direction. Figure 9D shows the associated camera pixels recording the responses of the panel pixels of Figure 9C. Figure 9E shows an exemplary of the camera pixels of Figure 9D. Figure 10A is an exemplary timing diagram of one of the signals suitable for determining the positions of the pixels of a flat panel display in accordance with an exemplary embodiment of the present invention. Figures 10B through 10G are diagrams in accordance with the present invention. An embodiment Exemplary images of the gate lines and data lines receiving the voltages shown in FIG. 10A. FIG. 11A is a diagram of a flat panel for driving data and gate lines using a voltage signal according to an exemplary embodiment of the present invention. One of the sections is a screenshot. The 11B and 11C are the intensity curves obtained along the X and Y directions of the image of Figure 11A. Figures 12A to 12C show the measurement with 201017155 according to an exemplary embodiment of the present invention. An exemplary process of an offset between a plane of a plane and a plane of a camera. Figures 13A through 13D illustrate one of the angles of rotation for determining a plane between a plane and a plane of a camera in accordance with an exemplary embodiment of the present invention. Demonstration process. Figure 14 is a diagram showing the flow of control and data between various components for generating a voltage map system in accordance with an exemplary embodiment of the present invention. Figure 15 shows the use of an image processing computer 600 in accordance with an embodiment of the present invention. [Description of main component symbols] 10...glass plate 124...transistor 15...modulator 126...external particles 18..LCD panel 128...residue 20,170...region 150, 180··· panel 25...air gap 152,162...panel alignment mark 30...panel pixel electrode 156...panel scribe 35...camera, imaging sensor 160...active Display area 45...LC material 172, 174 ... column 50... flat glass 182, 184, 186, 188... line 60, 70... pixel 200... spacer, gate even 100... 202...gasket, gate 102...VIOS 204...shield, data odd 104...image processing computer 206...shield, data even 106...dynamic pixel map 208...gate line 110.. Metal protrusion 210...data input line 112...ITO 300.. .LCD panel 114...ITO protrusion 302, ' 3022'3023...ChevronTM 116...metal shape pixel 118...rat shout 312 !...camera pixel, actual position 120...open circuit 3122...camera pixel, expected position 122...short circuit 350...image template 31 201017155 400··. LCD image spot 402...sub-region, reference sub- Area, reference image 404·.·image Sub-area image, reference sub-area, reference sub-area image, reference image, sub-area 500···system 5〇6...image processing computer 508.··dynamic pixel map generator 600..·image processing computer, computer system 602...processor 6〇4·.. busbar subsystem 606·.. storage subsystem 608·.. memory subsystem 610·., file storage subsystem 612... user interface input 614... use Interface rounding out ^ 616... network interface subsystem set 618... primary random access memory 620... read only memory 32

Claims (1)

201017155 VII. Patent Application Range: 1. A method for determining a position of a flat panel display relative to a position of a sensing head, the flat panel display comprising a plurality of pixels coupled to a plurality of data lines and a gate line, the method comprising The following steps: applying a first signal to the plurality of gate lines; capturing a response of the gate lines to the first signal; applying a second signal to the plurality of data lines; a response of the data line to the second signal; combining the first and second responses to generate a combined response; determining the intersection of the gate lines with the data lines using the combined response, the intersections representing the pixels The positions; the pixel positions are used to determine the offset and rotation values of the flat panel display relative to the sensing head. 2. The method of claim 1, further comprising the step of: simultaneously applying the first and second signals without exciting the pixels. 3. The method of claim 1, further comprising the steps of: applying the first signal during a first time period; and applying the second signal during a second time period, the second time period Does not overlap with the first time period. 4. The method of claim 1, wherein the sensing head comprises an imaging camera, wherein a first voltage image is used to capture the response of the gate 33 201017155 line, and a second is used therein The voltage image captures the response of the data lines. 5. The method of claim 1, wherein the sensing head comprises a detector operative to detect a response to an electron beam signal. 6. The method of claim 1, further comprising the steps of: capturing an image of a point on the panel; capturing a template of one of the repeating features of the panel; defining the template in the a pixel space of the sensing head; constructing an image of the template from the captured image site; calculating a difference between an actual position of the template and an expected position of the template, the actual position of the template Defined by the image of the template, the expected position of the template is defined by the known position of the repeating features of the panel; and the position of one of the images of the template is changed relative to the expected position of the template until the difference is satisfied A predetermined condition, wherein the difference indicates a characteristic of the panel being offset XY with respect to one of the sensing heads when the predetermined condition is satisfied. 7. The method of claim 6, wherein the repeating pattern is a panel of pixels. 8. The method of claim 6, further comprising the steps of: selecting a reference pixel on the panel; determining a position of the reference pixel on the template image; 201017155 image ===, test pixel At a position where the position of the image of the template is changed, and a position of the reference pixel in the image mode ===-predetermined condition 'where#_the condition is expected, and the reference pixel is at the reference pixel The difference between the position of the (4) position on the material template indicates the feature of the χ γ offset of the panel relative to the sensor head. 9. The method of claim 6 further comprising the steps of: Selecting a plurality of sub-areas; determining a position of the selected plurality of sub-areas on the template image; Calculating a difference between an expected position of the plurality of selected sub-regions and a corresponding position of the selected plurality of sub-regions on the image template; and changing a position of the image of the template until the selected ones A difference between an expected position of the plurality of sub-regions and a corresponding position of the plurality of selected sub-regions on the image template satisfies a predetermined condition 'where the selected plurality of sub-regions are satisfied when the predetermined condition is satisfied The difference between the expected location and the corresponding location of the selected plurality of sub-regions on the image template represents a characteristic of the XY offset of the panel relative to the sensing head. 10. The method of claim 6, wherein the condition is satisfied when the difference is less than a known value of 35 201017155. 11. The method of claim 6, wherein the condition is satisfied when the difference is greater than a known value. 12. The method of claim 6, further comprising the steps of: selecting an area among the captured image points; and displaying an image of the selected area laterally in the selected area according to the image One of the repeating features of the panel is expected to repeat one of the positions; the angular position of the image of the selected region is shifted relative to the direction of the lateral movement until the actual and expected position of the region satisfies a second condition, wherein the condition is satisfied A rotation angle between the panel and the sensing head is defined by an initial position of the selected area, an expected position of the selected area, and an image position of the selected area. 13. The method of claim 6, wherein the difference is calculated according to an interaction correlation algorithm. 14. The method of claim 6, wherein the difference is calculated based on an absolute difference and an algorithm. 15. Apparatus for operating a pixel position of a flat panel display, the flat panel display comprising a plurality of data lines and gate lines, the apparatus comprising: a signal generator operative to supply a first signal to the And a plurality of gate lines and a second signal are supplied to the plurality of data lines, a sensing head operable to capture a response of the gate lines to the first signal and further extracting the data The line is responsive to a 201017155 of the second signal; and a computer system operable to: combine the first and second responses to produce a combined response, and use the combined response to determine the gate and data lines Intersecting, the intersections representing the locations of the pixels; and using the pixel locations to determine the offset and rotation values of the flat panel display relative to the sensing head. 16. The device of claim 15 wherein the signal generator is operative to simultaneously supply the first and second signals without exciting the pixels. 17. The device of claim 15 wherein the signal generator is operative to supply the first signal during a first time period and to supply the second signal during a second time period, the The two time periods do not overlap with the first time period. 18. The device of claim 15, wherein the sensing head comprises an imaging camera, wherein the first voltage image is used to capture the response of the gate lines and a second voltage image is captured therein The response of the data lines. 19. The device of claim 15 wherein the sensing head comprises a detector operative to detect a response to an electron beam signal. 20. The device of claim 15, wherein the computer system is further operable to: retrieve a template of one of the repeating features of the panel; 37 201017155 defining the template in a pixel space of the sensing head Constructing an image of the template from a point image captured by the sensing head; calculating a difference between an actual position of the template and an expected position of the template, the actual position of the template Defined by the image of the template, the expected position of the template is defined by the known position of the repeating features of the panel; and the position of one of the images of the template is changed relative to the expected position of the template until the difference is satisfied A predetermined condition, wherein the difference indicates a characteristic of the panel being offset with respect to one of the sensing heads X γ when the predetermined condition is satisfied. 21. The device of claim 20, wherein the repeating pattern is a panel of pixels. 22. The device of claim 20, wherein the computer system is further operable to: select a reference pixel on the panel; determine a position of the reference pixel on the template image; calculate the reference pixel a difference between an expected position and the position of the reference pixel on the image template; and changing a position of the image of the template until an expected position of the reference pixel and the position of the reference pixel on the image template Satisfying a predetermined condition, wherein the difference between the expected position of the reference pixel and the position of the reference pixel on the image template when the predetermined condition is satisfied represents the XY offset of the panel relative to the sensing head移特特38 201017155 征0 23. The device described in item 2 () of the patent application is operable in one step to: select a plurality of sub-regions in the site; and determine the selected (four) town sub-regions on the template image Bit 6 is calculated between the expected position of the selected plurality of sub-regions and the corresponding position of the selected plurality of sub-regions on the image template Poor; and 'where the computer system enters a position of one of the images of the template until the expected position of the selected plurality of sub-areas and a corresponding position of the selected plurality of sub-areas on the image template meets a predetermined condition 'where the difference between the expected position of the selected plurality of sub-areas and the corresponding position of the selected plurality of sub-areas on the image template when the predetermined condition is satisfied indicates that the panel is relative to The characteristic of the XY offset of the sensing head. 24_ The device of claim 2, wherein the condition is satisfied when the difference is less than a known value. 25. The device of claim 2, wherein the condition is met when the difference is greater than a known value. 26. The device of claim 2, wherein the computer system is further operable to: select an area in the captured image position; set the image of the selected area laterally in the selection The region's 39 201017155 image is expected to repeat one of the positions depending on the repeating features of the panel; the direction relative to the lateral movement shifts the angular position of the image of the selected region until the actual and expected position of the region satisfies a second A condition wherein a rotation angle between the panel and the sensing head when the condition is satisfied is defined by an initial position of the selected area, an expected position of the selected area, and an image position of the selected area. 27. The device of claim 20, wherein the difference is calculated in accordance with an interaction correlation algorithm. 28. The device of claim 20, wherein the difference is calculated based on an absolute difference and an algorithm. 29. A method of identifying locations of a plurality of pixels formed in a plurality of panels of a flat panel display, the method comprising the steps of: supplying a voltage signal to a first panel of the panels such that Pixels disposed on at least one first edge of the first panel of the panel are presented with at least a subset of pixels disposed by the at least the first edge of the first panel of the panel The two voltage images are compared to different first voltage image contrasts; and the difference between the first and second image contrasts is used to identify the locations of the pixels of the first panel of the panels. 30. The method of claim 29, further comprising the steps of: supplying a second voltage signal to the first panel of the panels such that at least the first panel along the panels a second edge 201017155 sets the pixel to present a third voltage image contrast different from the second voltage image contrast; and uses the difference between the third and second image contrast to identify the first panel of the panel The location of the pixels. 31. Apparatus operable to identify a location of a plurality of pixels formed in one or more panels of a flat panel display, the apparatus comprising: a signal generator operative to supply a voltage signal to the a first panel of the panel; a sensing head operable to capture a voltage image of one of the pixels of the first panel of the panel, the captured voltage image being presented and the first along the panel a first comparison associated with the pixels of the at least one first edge of the panel, the captured voltage image exhibiting at least one of pixels disposed along the at least the first edge of the first panel of the panel a second comparison of the association, the first comparison being different from the second comparison; and a computer system adapted to use the difference between the first and second comparisons to identify the first of the panels The position of the pixels of the panel. 41