Abstract:
A manufacture method for a liquid crystal display device and the marks of a substrate thereof is submitted in this present invention. First, a substrate is provided for marked the marks. Then at least one high power light beam is used to focus on and melt the internal part of the substrate for forming the opaque areas. According to the arrangement of the opaque areas, which can be used as the alignment marks or the identification marks. Due to the position of the opaque areas formed by the high power light beam are accurate, the degree of accuracy in the follow-up assembly operation is improved.

Description:
RELATED APPLICATIONS  
       [0001]     The present application is based on, and claims priority from, Taiwan Application Serial Number 93129463, filed Sep. 29, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety.  
       FIELD OF THE INVENTION  
       [0002]     The present invention is related to a manufacture method for a liquid crystal display, and more particular, to a manufacture method for alignment marks in a substrate of the liquid crystal display.  
       BACKGROUND OF THE INVENTION  
       [0003]     Liquid crystal display (LCD) is a kind of display employing the characters of liquid crystal display to exhibiting images, cause thereof has more flexibility in dimension and weight compare with cathode ray tube (CRT). Liquid crystal display is employed in various kinds of field, such as mobile phone, personal digital assitant, digital camera, television, and banner advertisement.  
         [0004]     The flexibility in dimension and weight compare with cathode ray tube, which is due to the significant parts of the liquid crystal display are flat, such as a thin film transistor array substrate and a color filter substrate. Therefore, it&#39;s much easier than cathode ray tube to be cut in appropriate dimension according to a demand, and much lighter and handier than cathode ray tube which has huge three-dimensional shape.  
         [0005]     Because the liquid crystal display is manufactured by those stacked flat elements, and a light beam pass through such layered elements to exhibiting images. It is necessary to align the thin film transistor array substrate and color filter substrate accurately during combining them, then the liquid crystal can exhibit images correctly, and avoid to appearing some issues, such as color difference.  
         [0006]     The simplest conventional method for alignment and stacking the thin film transistor array substrate and color filter substrate, is to put those substrates both on the alignment device, and use the alignment mechanism as the standard of alignment for stacking process.  
         [0007]     Another conventional alignment method is to form some alignment marks at the surrounding or corner area of the thin film transistor array substrate and color filter substrate. Then the location of those substrates is adjusted via the alignment marks during stacking those two substrates. The alignment marks of the thin film transistor array substrate are formed in one process, and the alignment marks of the color filter substrate are form in another process. Those alignment marks are not formed in the same process and simultaneously. The process forming the alignment marks usually means the photolithograph process.  
         [0008]     As manufacturing technology development, the thin film transistor array substrate and the color filter substrate becomes larger and larger. The number of thin film transistor array panels and color filter panels separately disposed on the thin film transistor array substrate and the color filter substrate increase as the dimension of those two substrates. While more thin film transistor panels and color filter panels put on the substrates, the accuracy requirement according to the positions of the alignment marks will become more seriously. The conventional alignment methods mentioned above are both limited as the substrate size becoming larger.  
         [0009]     For example, while more than eight panels put on the same substrate, the accuracy of the positions of alignment marks will become poor or mistakable. Therefore, this kind of alignment method is limited when the size of the glass substrate becomes larger.  
         [0010]     Furthermore, both of the alignment method mentioned above also has a risk of contaminant particle caused by the manufacture process of the alignment marks. Hence, there is a demand existed for an alignment or manufacture method that can provide more accurate and faster alignment method for manufacture the liquid crystal display.  
       SUMMARY OF THE INVENTION  
       [0011]     One purpose of the present invention is to provide a method that improves the accurate of the alignment process.  
         [0012]     Another purpose of the present invention is to provide a method that simplifies the manufacture process of the alignment marks.  
         [0013]     Another purpose of the present invention is to provide a method that can form the alignment marks on plural substrates simultaneously in the same process.  
         [0014]     Another purpose of the present invention is to provide a method that can manufacture the liquid crystal display without contaminant particle.  
         [0015]     In order to achieve the purposes mentioned, the present invention provides a manufacture method of a liquid crystal display, which comprises the steps of: providing a plurality of substrates decided to form the alignment marks on the same places of each substrate; stacking and locating those substrates on a device employed for forming the alignment marks, wherein the alignment marks forming device comprising a high power light beam emitting head used for burning and melting the alignment marks in the internal part of one of the substrates, and burning and melting the same alignment marks in the internal part of another substrates by adjusting the focal point of the high power light beam; and assembling the predetermined substrates via the alignment marks in general alignment and assembly process. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]      FIG. 1  is a sketch of forming an opaque area via a high power light beam on a substrate of one embodiment of the present invention.  
         [0017]      FIGS. 2A-2D  are sketches of showing the alignment marks formed via the high power light beam on the substrate of another embodiment of the present invention.  
         [0018]      FIG. 3A  is a sketch of the alignment marks example which formed by the high power light beam on the substrate of another embodiment of the present invention.  
         [0019]      FIG. 3B  is a sketch of a literal pattern example which formed by the high power light beam on the substrate of another embodiment of the present invention.  
         [0020]      FIG. 3C  is a sketch of the dot matrix bar code pattern example which formed by the high power light beam on the substrate of another embodiment of the present invention.  
         [0021]      FIG. 4  is a vertical view of assembling two substrates of another embodiment of the present invention.  
         [0022]      FIG. 5A-5B  are sketches of forming the opaque areas via the high power light beam on a plurality of substrates of another embodiment of the present invention.  
         [0023]      FIGS. 6A-6F  are sketches of showing the alignment marks formed via the high power light beam on a plurality of substrates of another embodiment of the present invention.  
         [0024]      FIG. 7A  is a sketch of a device which used for forming the marks of another embodiment of the present invention.  
         [0025]      FIG. 7B  is a sketch of forming the marks via the high power light beam passing through a photo mask of another embodiment of the present invention.  
         [0026]      FIG. 8A-8E  are sketches of a manufacture method of liquid crystal panel of another embodiment of the present invention.  
         [0027]      FIG. 9A-9D  are sketches of another manufacture method of liquid crystal panel of the present invention.  
         [0028]      FIG. 10  is a flow chart in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]     The fundamental idea of the present invention is to form the marks in internal part of a substrate of the liquid crystal display by employing the characters of the high power light beam, such as high power, penetrability, and variable focal length. Hence, there are no effects or damages existing on the surface of the substrate, and no contaminant particles formed by the present inventive method. In addition, the marks formed via the present invention can be produced in the successive process, so the risk of errors during the manufacture process of the marks can be reduced.  
         [0030]     The glass substrates are usually selected as the substrates of the liquid crystal display. For example, the thin film transistor array and the color filter are manufactured via a variety of processes on the glass substrates. Because the glass material is transparent and meltable, as shown in  FIG. 1 , an ovoid opaque area  106  can be formed in the internal part of the substrate  102  by the heat caused by focusing of a high power light beam  104 , such as laser light beam.  
         [0031]     The opaque area  106  caused by focusing of the high power light beam  104  should be controlled under the thickness  108  of the substrate  102 . If the opaque area  106  is over the thickness  108 , the high power light beam  104  can damage the surface of the substrate  102 . According to the available laser technology, the dimension of the opaque area  106  can be controlled about 100 μm. In order to make the opaque area  106  totally in the internal part of the substrate  102 , the focusing area of the high power light beam  104  is decided by the thickness  108  of the substrate. Preferably, the dimension of the opaque area  106  is suggested smaller than half of the thickness  108 . In another words, if there is a major axis existed in the opaque area  106 , the major axis is suggested smaller than half of the thickness  108  of the substrate  102 . Further, the focusing time of the high power light beam  104  should also be controlled, or the substrate  102  will be deformed by the heat caused by the over focusing time, and the position of the opaque area  106  will be shifted too. The focusing time is according to the high power light beam  104 , material of the substrate  102  and other design factors, so it is hard to decide a proper focusing time. Hence, the temperature variation on the surface of the substrate is suggested between 0˜0.5° C. during forming opaque area  106 .  
         [0032]      FIGS. 2A-2D  disclose the present invention, which is employed to forming the opaque area. First, providing a substrate  202  and a high power light beam emitting device  204  as shown in  FIG. 2A , the high power light beam emitting device  204  has a focal point  206 , that means a high power light beam emitted from the high power light beam emitting device  204  will focus on the focal point  206 . In  FIG. 2B , the focal point  206  is adjusted into the predetermined position of the substrate  202  for forming the opaque area. As show in  FIG. 2C , the high power light beam emitting device  204  emits a high power light beam which burn and melt an opaque area  208  on the position of the adjusted focal point  206 . Shifting the high power light beam emitting device  204 , an opaque area  210  is formed in another position as shown in  FIG. 2D  by the same method as described above. Repeating the steps described before, a plurality of opaque areas can be formed in the same substrate and arranged as some designed specific marks.  
         [0033]      FIG. 3A  shows three kinds of alignment marks arranged by the ovoid opaque areas formed by the present invention. Besides the alignment marks, other kinds of marks, for example the glass identification code, is also can be formed by the present invention.  FIG. 3B  shows a literal pattern and  FIG. 3C  shows a dot matrix bar code pattern, wherein the left side of  FIG. 3C  is the original dot matrix bar code pattern, and the right one is the pattern formed by the present invention. Further more, the dot matrix bar code pattern also includes Datamatrix, Maxicode, Vericode, Softstrip, Codel, and Philips Dot Code etc.  
         [0034]     According to  FIG. 4 , a first substrate  402  and a second substrate  404  are assembled via the alignment marks formed by the present invention, there are a first alignment mark  408  arranged by a plurality of first opaque areas  406  in the internal part of the first substrate  402 , and there are a second alignment mark  412  arranged by a plurality of second opaque areas  410  and a glass identification code  416  arranged by a plurality of third opaque areas  414  in the internal part of the second substrate  404 . The first alignment mark  408  and the second alignment mark  412  are totally in the same shape, so the first substrate  402  and the second substrate  404  can be assembled accurately by completely overlapping the first alignment mark  408  and the second alignment mark  412 . The position of the first alignment mark  408 , the second alignment mark  412  and the glass identification code  416  can be formed at the surrounding, corner area or other places of the first substrate  402  and the second substrate  404  without influence the function thereof, and not limited in this embodiment of the present invention.  
         [0035]      FIG. 5A  and  FIG. 5B  disclose another embodiment of the present invention, and show the possibility for forming the alignment marks in a plurality of substrates simultaneously in the successive process. According this embodiment, the manufacture time of the alignment marks can be reduced without forming the alignment marks alone in each substrate process, and the errors between each alignment mark can also be reduced. First, as shown in  FIG. 5A , if a first substrate  502  and a second substrate  504  will be assembled in follow-up processes, or it&#39;s necessary to have the same shape alignment marks in the same positions of the first substrate  502  and the second substrate  504 , then as the situations described above, it&#39;s suitable to apply this embodiment of the present invention.  
         [0036]     First, stacking the first substrate  502  and the second substrate  504 , forming a first opaque area  508  in internal part of the first substrate  502  via a high power light beam  506  according to the processes described before, then adjusting the focal length of the high power light beam  506  to focusing inside of the second substrate  504 , a second opaque area  510  can be formed in internal part of the second substrate  504  as shown in  FIG. 5B , wherein the first opaque area  508  and the second opaque area  510  are formed in the successive process, so the errors between thereof can be reduced.  
         [0037]      FIGS. 6A-6F  describe the detail of this embodiment of the present invention. As shown in  FIG. 6A , a first substrate  602  and a second substrate  604  are stacked, and a high power light beam emitting device  606  shifted to a first location, wherein the high power light beam emitting device  606  has a focal point  608 . In  FIG. 6B , the focal point  608  is adjusted to a predetermined position for forming an opaque area which is in an internal part of the first substrate  602 . As shown in  FIG. 6C , the high power light beam emitting device  606  emits a high power light beam to burn and melt a first opaque area  610  in the focal point. According to  FIG. 6D , the focal point  608  is vertical adjusted into the internal part of the second substrate  604 . In  FIG. 6E , in the internal part of the second substrate  604 , a second opaque area  612  corresponding to the first opaque area  610  is burnt and melted as the same process described before. As shown in  FIG. 6F , shifting the high power light beam device  606  to a second location, a third opaque area  614  and a fourth opaque area  616  are respectively formed in different positions of the first substrate  602  and the second substrate  604  by the same method described before. Repeating the steps described above, the totally corresponding alignment marks of the first substrate  602  and the second substrate  604  can be formed.  
         [0038]     According to this embodiment of the present invention, the manufacture time of the alignment marks can be reduced by forming in a short time. On the other hand, the manufacture sequence of the opaque areas is not limited in this embodiment. For example, as shown in  FIG. 5A  and  FIG. 5B , forming the second opaque area  510  early and forming the first opaque area  508  latter is acceptable, or as shown in  FIG. 6A-6F , forming the second opaque area  610  early and forming the first opaque  608  latter is also acceptable. Further, the number of the stacked substrates for the present invention is not limited in two substrates. In multi-stacked substrates situation, it&#39;s suggested to forming the opaque area in the farther substrate from the high power light beam emitting head as earlier as possible, or the opaque area in the closer substrate will interfere with the forming of the opaque area in the farther substrate.  
         [0039]      FIG. 7A  discloses a device which can achieve the purpose of the present invention, wherein a substrate  702  is deposited in a base (not shown in the figure), and there are a plurality of high power light emitting devices  704  arranged upon the predetermined positions for forming alignment marks of the substrate  702 . During manufacturing the alignment marks, these high power light beam emitting devices  704  operate simultaneously for forming the alignment marks in predetermined position of the substrate  702 , wherein the alignment marks can also be formed by shifting horizontal shifting the high power light beam device  704  or the base of the device, or as shown in  FIG. 7B , employing a photo mask  706  located between the substrate  702  and the high power light emitting device  704  to forming the alignment marks in the same time. In practice, the number or locations of the high power light beam-emitting device are not limited in this embodiment of the present invention.  
         [0040]      FIGS. 8A-8E  show another embodiment of the present invention, which is employed in the alignment marks of the liquid crystal display. As shown in  FIG. 8A , a first substrate  802  and a second substrate  804  employed in the liquid crystal display are provided first, then a thin film transistor array structure  806  and a plurality of first alignment marks  810  are formed separately on the surface and in the internal part of the first substrate  802 , and a color filter structure  808  and a plurality of second alignment marks  812  are also formed separately on the surface and in the internal part of the second substrate  804 , wherein the first alignment marks  810  and the second alignment marks  812  have the same pattern, and both are formed via the manufacture methods of alignment marks described before simultaneously or separately. In  FIG. 8B , the first substrate  802  are stacked with the second substrate  804 , wherein the first alignment marks  810  are corresponding to the second alignment marks  812 . There are a sealant  814  applying between the first substrate  802  and the second substrate  804 . In  FIG. 8C , a plurality of liquid crystal molecules are injected into the space formed by the first substrate  802 , the second substrate  804 , and the sealant  814 . In  FIG. 8D , an end sealant  816  is applied in the sealant  814  to forming a closed seal pattern. At last in  FIG. 8E , cutting the part which is not used for displaying image of the first substrate  802  and the second substrate  804 , this part may include where the first alignment marks  810  and the second alignment marks  812  disposed. After the process described above, a liquid crystal panel used for liquid crystal display can be manufactured. According to this embodiment, it&#39;s also acceptable to form the thin film transistor array structure on the second substrate, the color filter structure on the first substrate, or the color filter integrated with the thin film transistor array structure on one of the first substrate and the second substrate.  
         [0041]      FIGS. 9A-9D  show another embodiment of the present invention. In  FIG. 9A , first providing a first substrate  902  and a second substrate  904 , a first alignment marks  910  composed of a plurality of opaque areas are formed in the internal part of the first substrate  902 , and a second alignment marks  912  composed of a plurality of opaque areas are formed in the internal part of the second substrate  904  with a color filter integrated with a thin film transistor array structure  906  on the surface of the second substrate  904 , wherein the first alignment marks  910  and the second alignment marks  912  are in the same pattern and formed by the same process which described before. In  FIG. 9B , the first substrate  902  are stacked with the second substrate  904 , wherein a plurality of drops or enough quantity of liquid crystal molecules  918  are dripped on the second substrate  904 , the first alignment marks  910  and the second alignment marks  912  are corresponding to each other, and a sealant  914  is disposed between the first substrate  902  and the second substrate  904  during assembling process. In  FIG. 9C , after assembling the first substrate  902  and the second substrate  904 , a plurality of liquid crystal molecules  918  are dispensed in the space formed by the first substrate  902 , the second substrate  604 , and sealant  914 . At last in  FIG. 9D , cutting the part which is not used for displaying image of the first substrate  902  and the second substrate  904 , this part may include where the first alignment marks  910  and the second alignment marks  912  disposed. After the process described above, a liquid crystal panel used for liquid crystal display can be manufactured. According to this embodiment, it&#39;s also acceptable to form the thin film transistor array structure on one of the first substrate and the second substrate, and form the color filter structure on another one of the first substrate and the second substrate.  
         [0042]      FIG. 10  discloses a flow chart of the present invention. In a first step  1002 , a substrate decided to be formed marks is provided, wherein the marks means the alignment marks or the glass identification code. In a second step  1004 , a high power light beam-emitting device is provided for forming the marks. In a third step  1006 , the high power light beam emitting device is shifted into a proper position, then a focal point of the high power light beam device is adjusted into the internal part of the substrate. In a fourth step  1008 , a high power light beam emits form the high power light beam device and form an opaque area in the position where the focal point is in the internal part of the substrate.  
         [0043]     Repeating the steps described above, a plurality of marks composed of the opaque areas can be formed in the internal part of the substrate, wherein the high power light beam comprises such as an excimer laser, a solid state laser or other high power light beam which can achieve the same effect, then assembling the substrates via the alignment marks formed by the present invention, wherein the assembling process can be employed the general assembling process.  
         [0044]     Having thus described the invention in detail, it will be recognized that such detail need not be strictly adhered to but that various changes and modifications may suggest themselves to one skilled in the art, all falling within the scope and spirit of the present invention, as defined by the subjoined claims.