Abstract:
Each layer of a display device is divided into many shot areas. Suspected division area is then set so that corresponding areas for all of the layers are included in it. All of the layers are then divided at one time along the suspected division area. Finally, a portion in the suspected division area that is not included in shot area of any layer is provided with a light-resistant coating.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is a Divisional of application Ser. No. 09/572,945, filed May 18, 2000, now allowed. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to layout designing method of a display device.  
           [0004]    2. Description of the Related Art  
           [0005]    In a liquid display device using a TFT (thin film transistor) as a switching element, for instance, four panels  12  are prepared on a sheet of glass plate  11  as shown in FIG. 1. Each of the panels  12  is divided into, for instance, four shot areas (A, B, C, D) as shown in FIG. 2.  
           [0006]    [0006]FIG. 3 shows a panel  12  in an enlarged form. In FIG. 3, in a display section of each of the shot areas  12   a,    12   b,    12   c,  and  12   d  indicated by the signs A, B, C, and D, a TFT switching pattern  13 , a pixel pattern  14 , or the like are formed as shown in FIG. 4. The TFT switching pattern  13  is formed with a layer construction consisting of  3  to  7  layers with such components as a gate bus line  13   g  or a drain bus line  13   d.    
           [0007]    In the layout designing method based on the conventional technology, at first panel data concerning TFTs or pixels in a display device is prepared, and then one sheet of panel  12  is divided with a division tool or the like into a plurality of shot areas  12   a,    12   b,    12   c,  and  12   d . However, if the gate bus line  13   g  or drain bus line  13   d  is divided at a place where a switching performance of a transistor  
           [0008]    is badly affected, or if one pixel pattern  14  is divided into two sections, characteristics of the pixel at such a place changes, which in turn may cause non-uniformity in display.  
           [0009]    To prevent generation of this non-uniformity in display, it is necessary to divide a G layer in which the gate bus line  13   g  is formed along a first division line A-A evading the gate electrode section as shown in FIG. 5. Regarding I layer in which the drain bus line  13   d  is formed, it is necessary to divide this I layer along a second division line B-B evading the source/drain area. Regarding Px layer in which the pixel pattern is formed, it is necessary to divide this Px layer along a third division line C-C so that a single pixel will not be divided.  
           [0010]    In other layers not shown in these figures, there are line positions suited to division, and the division line positions are generally different from layer to layer. In other words, it is impossible to divide one panel into a plurality of shot areas by setting the same division line for all layers.  
           [0011]    Therefore, in the conventional technology, appropriate division line is set for each layer. Following procedure is employed when manufacturing a display device. That is, as shown in FIG. 6, reticules  13   a,    13   b,    13   c,    13   d  corresponding to the shot areas  12   a,    12   b,    12   c,    12   d  indicated by the signs A, B, C, D are prepared for each layer, and exposure is made to resist applied on the glass plate  11  using these reticules  13   a,    13   b,    13   c,  and  13   d  successively and with an exposure device such as a stepper.  
           [0012]    The layout designing method based on the conventional technology is described below with reference to FIG. 7 to FIG. 15B. FIG. 7 is a flow chart showing a flow in reticule preparation based on the conventional type of layout designing method. FIG. 8 to FIG. 15B show examples of geometrical patterns so that the flow chart above can easily be understood.  
           [0013]    The examples of geometrical pattern shown in FIG. 8 are based on the assumption that a panel  21  is divided into four sections and comprises two layers, namely a G layer in which a heart-shaped pattern  22  is formed and an I layer in which a square pattern  23  is formed. As shown in FIG. 9, G 1 -G 2  and  11 - 12  are division lines for the G layer and I layer respectively. It is assumed that there occurs no functional problem in the panel pattern shown in the figure.  
           [0014]    When layout designing is started, at first, panel data is prepared as shown in FIG. 7 (step S 1 ). FIG. 8 shows a panel image prepared based on the panel data. At the next step, all layers are divided into a plurality of areas respectively (step S 2 ) . FIG. 9 shows divided images of all layers, namely the G layer and I layer in this example.  
           [0015]    Images for the shot areas obtained by dividing the panel are located in data concerning the reticule image, thus a reticule image being prepared (step S 3 ) . Process patterns such as an alignment mark are prepared at the same time.  
           [0016]    At the next step, a single layer, for instance, the G layer is divided (step S 4 ). FIG. 10 shows an image  24  of those obtained by dividing the G layer to four sections. FIG. 10 to FIG. 15B show only GA and IA shot areas positioned at the light upper section of the FIG. 9 together with the G layer and I layer. A shading band (described as blind pattern hereinafter) and an auxiliary pattern are added to a section around the four images obtained by dividing the G layer (step S 5 ) FIG. 11 shows a state where a blind pattern  25  is added to a divided image for the shot area GA in the G layer.  
           [0017]    At the next step, whether all of the layers have been divided or not is determined (step S 6 ). In this example, as the I layer has not been divided, the processing at step S 4  is executed to divide the I layer. FIG. 12 shows an image  26  of the shot area IA among the four areas obtained by dividing the I layer. At the next step, a blind pattern and an auxiliary pattern are added to a section around the four images obtained by dividing the I layer (step S 5 ). FIG. 13 shows a state where a blind pattern  27  is added to a divided image  26  of the shot area IA in the I layer.  
           [0018]    The processing from step S 4  to step S 6  is repeated until all of the layers are divided, and when all of the layers are divided, preparation of designing data is finished (step S 7 ). FIG. 14A and FIG. 14B show the prepared designing data  28 ,  29  for the G layer and I layer respectively.  
           [0019]    Based on the prepared designing data, exposure data and reticules are prepared (step S 8 ). FIG. 15A and FIG. 15B show exposure data and reticules  30 ,  31  for the G layer and I layer respectively.  
           [0020]    In the layout designing method based on the conventional technology as described above, the processing for division is executed by setting divided areas for each layer taking into account a switching pattern or a pixel pattern, so that the processing for division is required to be executed repeatedly until all layers have been divided. Time required for dividing one layer is around 1 hour. Therefore, for instance, for a 15-inch display device comprising  5  layers about five hours are required until the processing for dividing all of the layers is finished.  
           [0021]    Therefore, although reduction of production cost and designing cost for a display device is strongly desired recently, it has been difficult to reduce the designing cost.  
         SUMMARY OF THE INVENTIONS  
         [0022]    It is an object of the present invention to provide a layout designing method of a display device which makes it possible to shorten time required for designing a display device and also to reduce the designing cost.  
           [0023]    To achieve the object described above, in the layout designing method of a display device according to one aspect of the present invention, when designing a display panel comprising a plurality of layers and designed by dividing each layer to a plurality of short areas, a suspected division area is set so that shot areas corresponding to all layers are included, all of the layers are divided in batch along the suspected division area, and by treating a portion not included in a shot area of each layer in the suspected division area obtained as described above, an unnecessary portion is hid.  
           [0024]    In the layout designing method of a display device of another aspect of the present invention, when designing a display panel comprising a plurality of layers and designed by dividing each layer to a plurality of short areas, all of divided areas in all layers are aligned to each other by aligning other layers to a reference layer, and all of the layers are divided in batch along the aligned areas.  
           [0025]    Shot areas are positioned at reticules by offsetting each shot area by a rate of displacement of other layers to the reference layer. Or, a rate of displacement of other layers to the reference layer is given as an offset rate in exposure to an exposure device.  
           [0026]    According to the invention, as all of layers can be divided in batch, the time required for division can be shortened, and further the reduction cost can be reduced.  
           [0027]    Other objects and features of this invention will become apparent from the following description with reference to the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]    [0028]FIG. 1 shows an image of the glass from which a display device is prepared;  
         [0029]    [0029]FIG. 2 shows a general glass image of a display device comprising a plurality of shot areas;  
         [0030]    [0030]FIG. 3 shows a general glass image of a display device comprising a plurality of shot areas;  
         [0031]    [0031]FIG. 4 shows a general image of a short area in a display image; FIG. 5 shows a general image of a short area in a display image;  
         [0032]    [0032]FIG. 6 shows a general glass image and reticules of a display device comprising a plurality of shot areas;  
         [0033]    [0033]FIG. 7 is a flow chart showing an flow of operations for preparing reticules in the layout designing method based on the conventional technology;  
         [0034]    [0034]FIG. 8 is a simulated view showing an example of geometric pattern prepared in the operation flow shown in FIG. 7;  
         [0035]    [0035]FIG. 9 is a simulated view showing an example of geometric pattern prepared in the operation flow shown in FIG. 7;  
         [0036]    [0036]FIG. 10 is a simulated view showing an example of geometric pattern prepared in the operation flow shown in FIG. 7;  
         [0037]    [0037]FIG. 11 is a simulated view showing an example of geometric pattern prepared in the operation flow shown in FIG. 7;  
         [0038]    [0038]FIG. 12 is a simulated view showing an example of geometric pattern prepared in the operation flow shown in FIG. 7;  
         [0039]    [0039]FIG. 13 is a simulated view showing an example of geometric pattern prepared in the operation flow shown in FIG. 7;  
         [0040]    [0040]FIG. 14A is a simulated view showing an example of geometric pattern prepared in the operation flow shown in FIG. 7;  
         [0041]    [0041]FIG. 14B is a simulated view showing an example of geometric pattern prepared in the operation flow shown in FIG. 7;  
         [0042]    [0042]FIG. 15A is a simulated view showing an example of geometric pattern prepared in the operation flow shown in FIG. 7;  
         [0043]    [0043]FIG. 15B is a simulated view showing an example of geometric pattern prepared in the operation flow shown in FIG. 7;  
         [0044]    [0044]FIG. 16 is a flow chart showing a flow of operations for preparation of reticules based on a layout designing method according to a first embodiment of the present invention;  
         [0045]    [0045]FIG. 17A is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 16;  
         [0046]    [0046]FIG. 17B is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 16;  
         [0047]    [0047]FIG. 18A is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 16;  
         [0048]    [0048]FIG. 18B is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 16;  
         [0049]    [0049]FIG. 19A is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 16;  
         [0050]    [0050]FIG. 19B is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 16;  
         [0051]    [0051]FIG. 20 is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 16;  
         [0052]    [0052]FIG. 21A is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 16;  
         [0053]    [0053]FIG. 21B is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 16;  
         [0054]    [0054]FIG. 22 is a flow chart showing a flow of operations for preparing reticules based on the layout designing method according to a second embodiment of the present invention;  
         [0055]    [0055]FIG. 23A is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 22;  
         [0056]    [0056]FIG. 23B is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 22;  
         [0057]    [0057]FIG. 24A is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 22;  
         [0058]    [0058]FIG. 24B is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 22;  
         [0059]    [0059]FIG. 25A is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 22;  
         [0060]    [0060]FIG. 25B is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 22;  
         [0061]    [0061]FIG. 26 is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 22;  
         [0062]    [0062]FIG. 27A is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 22;  
         [0063]    [0063]FIG. 27B is a simulated view showing an example of geometrical pattern prepared in the operation flow shown in FIG. 22. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0064]    The display device layout designing methods according to embodiments of the present invention are described in detail below.  
         [0065]    [0065]FIG. 16 is a flow chart showing a flow of operations for preparation of reticules based on the display device layout designing method according to a first embodiment of the present invention. FIG. 17A to FIG. 21B show examples of geometric pattern provided so that the flow chart can easily be understood, and the examples of geometric pattern are applicable when layout designing is executed for the panel image and division image shown in FIG. 8 and FIG. 9 respectively. FIG. 17A to FIG. 21B show only shot area GA and shot area IA positioned in the left upper section of FIG. 9 in both the G layer and I layer (same is the case with FIG. 23A to FIG. 27B).  
         [0066]    As shown in FIG. 16, when layout designing is started, at first panel data corresponding to the panel image shown in FIG. 8 is prepared (step S 11 ). At the next step, all layers are divided into a plurality of areas as shown by the division images shown in FIG. 9 (step S 12 ). The procedure up to step S 12  is the same as that in the conventional technology, but the prepared divided areas are temporary ones.  
         [0067]    Based on the all prepared areas for all layers, a suspected division area is then prepared so that all of the divided areas for each layer are included (step S 13 ). More specifically, when a shot area  41  in the G layer and a shot area  42  in the I layer are displaced from each other as shown, for instance, in FIG. 17A, a suspected division area  43  is set so that the short areas  41 ,  42  for the layers GA and IA are included.  
         [0068]    Although not specifically limited, the suspected division area is defined by coordinates of a vertex M included in the shot area  41  for the G layer but not included in the shot area  42  for the I layer and coordinates of a vertex N included in the shot area  42  for the I layer but not included in the shot area  42  for the layer I. Temporarily divided areas axe prepared also for other divided areas, namely for shot areas GB and IB, shot areas GC and IC, and shot areas GD and ID shown in FIG. 9 in the similar way.  
         [0069]    At the next step, images of shot areas obtained by dividing each layer are located in data for reticule images, and reticule images are prepared (step S 14 ). Process patterns such as an alignment mark are also prepared.  
         [0070]    All layers are then divided respectively based on the suspected division area (step S 15 ) . In other words, all of the layers are divided in batch based on the suspected division area. FIG. 18A shows a division image  44  of the suspected division area including shot areas for the layers GA and IA. FIG. 18B images  45 ,  46  of shot areas corresponding to the suspected division area shown in FIG. 18A for each of the G layer and I layer.  
         [0071]    At the next step, a blind pattern is added to area which is not included by its nature in the shot area GA in the suspected division area. Further, a blind pattern is added also to an area which is not included by its nature in the shot area IA of the suspected division area. Further, a blind pattern is added to a section around the suspected division area. Further, a auxiliary patter is added (step S 16 ).  
         [0072]    [0072]FIG. 19A shows a state where blind patterns  47 ,  48 ,  49  are added to sections around an area not included in the shot area GA, an area not included in the shot area IA, and a divided image  44 . FIG. 19B shows images of the G layer and I layer obtained by the image shown in FIG. 19A.  
         [0073]    In this stage, preparation of designing data is completed (step S 17 ). FIG. 20 shows prepared designing data  50 . Based on the obtained designing data, exposure data and reticules are prepared (step S 18 ). FIG. 21A and FIG. 21B show exposure data and reticules  51 ,  52  for the G layer and I layer respectively.  
         [0074]    As described above, according to the first embodiment, when a display panel comprising a plurality of layers and designed by dividing each layer to a plurality of shot areas, a suspected division area is set so that shot areas corresponding to all of the layers are included, and all of the layers are divided in batch along the suspected division area, so that the time required for division of each layer can be shortened. Therefore, the designing cost can be reduced.  
         [0075]    More specifically, in a case of a 5-inch display panel in which there are six types of shots, twenty total number of shots, and five layers, then five hours are required for division in the conventional technology, but it is estimated that only one hour is required according to the technology described in the first embodiment. Further, in a case of a 21-inch display panel in which there are fifteen types of shots, twenty-six total number of shots, and twenty-six layers, twenty-three hours is required for division in the conventional technology, but it is estimated that only 2.5 hours are required according to the technology described in the first embodiment.  
         [0076]    A blind such as a stepper as an accessory may be used for blinding in place of shading an unnecessary potion by adding blind patterns  47 ,  48  to an area not included in the shot area GA and an area not included in the shot area IA of an image  44  for the suspected division area, or blind patterns  47 ,  48  and a blind for an exposure device may be used together.  
         [0077]    [0077]FIG. 22 is a flow chart showing a flow of operations for preparation of reticules based on the display layout designing method according to a second embodiment of the present invention. FIG. 23A to FIG. 27B show examples of geometric pattern used when layout designing is executed for the panel image and division image shown in FIG. 8 and FIG. 9 respectively.  
         [0078]    As shown in FIG. 22, when layout designing is started, at first panel data for the panel image shown in FIG. 8 is prepared (step S 21 ). At the next step, all layers are divided as shown by the division image shown in FIG. 9 (step S 22 ). The process up to this step is the same as that in the conventional technology, however, the obtained divided areas are temporary divided areas.  
         [0079]    Then a layer is used as a reference, and shot areas for other layers are aligned to the short areas in the reference layer (step S 23 ). More specifically, for instance, as shown in FIG. 23A, when the shot area  61  of the G layer and shot area  62  of the I layer are displaced from each other, the I layer is used as a reference layer as shown in FIG. 23B, and the shot area  61  of the layer G is aligned to the shot area  62  of the I layer to obtain an area  63 .  
         [0080]    Coordinates of the G layer are shifted by the amount of displacement of the G layer from the I layer. The coordinates values maybe shifted in designing data by differentiating structure of each layer, or may be changed by means of logical processing for each geometry. Other divided areas, namely shot areas GB, GC, and GD are similarly aligned to the shot areas IB, IC, and ID.  
         [0081]    At the next step, images of the divided shot areas are located in data for reticule images to prepared reticule images (step S 24 ). Similarly, process patterns such as an alignment mark are prepared.  
         [0082]    As corresponding shot areas for all layers are aligned to each other, all of the layers are divided in batch (step S 25 ). FIG. 24A shows a division image  64  of an area aligned to the shot area IA by displacing the short area GA. FIG. 24B shows images  65 ,  66  of areas corresponding to those in FIG. 24A for the layer G and layer I.  
         [0083]    Blind patterns are added to sections around the areas divided in batch (step S 26 ). FIG. 25A shows a state where a blind pattern  67  is added to a section around the image  64  of the areas divided in batch. FIG. 25B shows images obtained by dividing the image shown in FIG.  25 A to those for the G layer and I layer.  
         [0084]    In this stage, preparation of designing data is finished (step S 27 ). Based on the obtained designing data, exposure data and reticules are prepared (step S 28 ). When preparing reticules, for the layers (G layer) other than the layer treated as a reference step S 23  (I layer), the shot areas are offset by the amount of displacement for aligning the other layers to the reference layer. FIG. 27A and FIG. 27B show exposure data and reticules  69 ,  70  for the G layer and I layer.  
         [0085]    According to the second embodiment, when a display panel comprising a plurality of layers and designed by dividing each layer to a plurality of shot areas, divided areas for all layers are aligned by other layers to a reference layer, and all of the layers are divided in batch along the aligned divided areas, so that the time required for division can be reduced. Further the designing cost can be reduced.  
         [0086]    More specifically, in a case of a 5-inch display panel in which there are six types of shot, twenty shots, and five layers, or in a case of a 21-inch display panel in which there are fifteen types of shot, twenty-six shots, and six layers, it is estimated that the time required for division is one hour or 2.5 hours like in the first embodiment respectively.  
         [0087]    In place of offsetting shot areas to reticules for other layers (G layer) other than the layer treated as a reference at step S 23  (I layer), exposure may be performed, when the processing for exposure is performed with an exposure device such as a stepper, by offsetting the shot areas by a rate of displacement of other layers to the reference layer in alignment.  
         [0088]    The present invention is applicable not only to a case where two layers, namely the G layer and I layer are divided in batch, but also to a case where three of more layers are divided in batch. When a number of layers constituting a display panel is three or more, only some of the layers may be divided in batch. Further the present invention is applicable not only to designing of a display device, but also to designing of a device comprising a plurality of layers and designed by dividing each layer to a plurality of shot areas.  
         [0089]    According to the layout designing method of a display device of one aspect of the present invention, when a display panel comprising a plurality of layers and designed by dividing each layer to a plurality of shot areas is designed, a suspected division area is set so that corresponding layers for all of the layers are included, and all of the layers are divided in batch along the suspected division area, so that the time required for division can be shortened. As a result, the designing cost can be reduced.  
         [0090]    According to the layout designing of a display device of another aspect of the present invention, when a display panel comprising a plurality of layers and designed by dividing each layer to a plurality of shot areas, divided areas for all layers are aligned by aligning other layers to a reference layer, and all of the layers are divided in batch along the aligned divided areas, so that the time required for division can be shortened. As a result, the designing cost can be reduced.  
         [0091]    Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art which fairly fall within the basic teaching herein set forth.