Abstract:
A method of forming a laminated glass substrate structure suitable for use in a display device or the like, includes the steps of: a) preparing a first glass substrate having first and second main faces; b) preparing a second glass substrate having third and fourth main faces; c) after the steps a) and b), adhering the first and second glass substrates with a space formed therebetween and with the third main face facing to the second main face; and d) after the step c), performing a smoothing process relative to all edges excepting one edge among edges defining the first main face. The laminated glass substrate structure provides an improved load resistance.

Description:
[0001]    This application is based on Japanese Patent Application No. 9-66796 filed on Mar. 19, 1997, the entire contents of which are incorporated herein by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    a) Field of the Invention  
           [0003]    The present invention relates to a glass substrate structure and its manufacture method, and more particularly to a laminated glass substrate structure suitable for a display device or the like and its manufacture method.  
           [0004]    b) Description of the Related Art  
           [0005]    A glass substrate has the characteristics that it is hard and not susceptible to scratches and that a transparent glass substrate can be manufactured easily. By positively utilizing these characteristics, a glass substrate is used for forming various types of windows and display panels. For example, a liquid crystal display (LCD) is formed by laminating a pair of glass substrates and injecting liquid crystal into liquid crystal cells formed in between the pair of glass substrates. A plasma display panel (PDP) also uses a similar laminated glass substrate structure.  
           [0006]    A glass substrate of a desired size is formed from a large plate glass by scribing the surface with a diamond cutter or the like and cleaving it by applying a bending stress. For example, in the manufacture of a liquid crystal display, a large plate glass is often cut into four pieces (generally called “four-plane cut”). It is known that a cut plane of glass has very sharp edges. In order to avoid handling danger or in order to prevent the generation of glass chips at processes after cutting, it is also known to chamfer each edge of a glass substrate.  
           [0007]    If foreign materials such as chips of glass substrates are mixed, a fatal defect such as pin holes may be formed in glass substrates of photomasks or electronic devices such as LCD. It is known that micro cracks are formed in a glass substrate chamfered by mechanical grinding with diamond or the like and may generate fine particles. Various methods have been proposed in order to prevent the generation of fine particles from a glass substrate.  
           [0008]    One problem associated with a glass substrate is that it is heavier than a plastic plate or the like. A glass substrate structure, particularly a laminated glass substrate structure with a pair of glass substrates adhered together, is likely to become heavy. A laminated structure often becomes thick. Using a thin glass substrate has been desired in order to thin and lighten LCDs and PDPs. However, a thin glass substrate is easy to be broken. It is desired that cracks and breaks are not formed if an applied pressure is within a predetermined range, although this range depends on application fields of glass substrates.  
           [0009]    For example, consideration should be paid to the fact that a user often presses the display surface of LCD. It is required that a laminated glass substrate structure of LCD is not broken even if a pressure within a certain range is applied to the display surface.  
           [0010]    In a laminated glass substrate structure of LCD, a resistance to pressure applied to the structure in one direction is required to have a certain value or larger, as described above. However, techniques for improving such a load resistance of a glass substrate are not know to date.  
         SUMMARY OF THE INVENTION  
         [0011]    It is an object of the present invention to provide a laminated glass substrate structure with an improved load resistance.  
           [0012]    It is another object of the present invention to provide a method of manufacturing a laminated glass substrate structure capable of improving a load resistance.  
           [0013]    According to one aspect of the present invention, there is provided a laminated glass substrate structure comprising: a first glass substrate having first and second main faces, all edges excepting one edge among edges defining the first main face having been subjected to a smoothing process; and a second glass substrate having third and fourth main faces, two edges among edges defining the fourth main face not subjected to the smoothing process, the second glass substrate being adhered to the first glass substrate with a space formed therebetween and with the third main face facing to the second main face.  
           [0014]    According to another aspect of the present invention, there is provided a method of forming a laminated glass substrate structure, comprising the steps of: a) preparing a first glass substrate having first and second main faces; b) preparing a second glass substrate having third and fourth main faces; c) after the steps a) and b), adhering the first and second glass substrates with a space formed therebetween and with the third main face facing to the second main face; and d) after the step c), performing a smoothing process relative to all edges excepting one edge among edges defining the first main face. The laminated glass substrate structure provides an improved load resistance. According to the experiments made by the present inventors, as a pressure is applied to one surface of a laminated glass substrate structure, first break occurs in a glass substrate on the side opposite to the glass substrate applied with the pressure. A break of a glass substrate mainly occurs in a surface applied with a tensile stress.  
           [0015]    It has been found that a glass substrate having edges with micro cracks or chips and applied with a static load breaks by extending a crack or chip on one side to another one on another side. Namely, if a glass substrate has cracks or chips on only one side, the glass substrate is hard to be broken.  
           [0016]    The load resistance of a glass substrate can therefore be improved by performing the smoothing process for edges excepting one among all edges defining the first main face applied with a largest tensile stress.  
           [0017]    All the edges may also be subjected to a smoothing process or processes.  
           [0018]    The smoothing process improves a resistance to a static load to be applied by a user of a laminated glass substrate so that it is sufficient if this process is performed after a pair of glass substrates is adhered. A pair of glass substrates is often adhered together by making at least two sides flush with each other. In such a case, if the smoothing process is performed for the flushed two sides of one of the substrates required of a higher load resistance, the smoothing process is often performed also for two sides of a glass substrate which is less required to be made resistant to a static load.  
           [0019]    As above, the load resistance of a laminated glass substrate can be improved.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]    [0020]FIGS. 1A and 1B are perspective views of laminated glass substrate structures according to embodiments of the invention.  
         [0021]    [0021]FIGS. 2A to  2 E are schematic plan views illustrating smoothing processes (rough surface removing or mitigating processes) according to embodiments of the invention.  
         [0022]    [0022]FIGS. 3A to  3 D are a plan view and cross sectional views showing a liquid crystal display according to an embodiment of the invention.  
         [0023]    [0023]FIGS. 4A to  4 E are plan views and cross sectional views illustrating main processes of a manufacture method of a liquid crystal display according to an embodiment of the invention.  
         [0024]    [0024]FIG. 5 is a table showing experiment results of samples formed by the embodiment methods of the invention.  
         [0025]    [0025]FIGS. 6A to  6 E are a perspective view and schematic diagrams illustrating preliminary experiments made by the present inventors.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    Prior to describing the embodiments of the invention, preliminary experiments made by the present inventors will be explained. FIGS. 6A to  6 E are schematic diagrams illustrating the preliminary experiments.  
         [0027]    [0027]FIG. 6A shows a glass substrate  101  cut in a predetermined size. The glass substrate  101  has a pair of main faces  102  and side faces  103 . An edge  104  is formed at the boundary between the main face  102  and each side face  103 . Namely, the main face  102  is defined by four edges  104 .  
         [0028]    [0028]FIG. 6B is a schematic diagram showing in a magnified scale an edge of a glass substrate cut with a diamond cutter. Small cracks and chippings can be observed at an edge  104 .  
         [0029]    [0029]FIG. 6C is a schematic plan view of a glass substrate with breaks formed by a static load experiment. Small cracks and chips  105  exist on edges  104  of the glass substrate. As a static load was applied to one main face of the glass substrate  101 , a break  106  was formed.  
         [0030]    It has been found that every break extends between different sides and does not couple different cracks and chips on the same side. A break is supposedly formed if latent cracks and chips at the edges  104  extend and the latent cracks generated from two cracks or chips meet together, while a static load is applied to the glass substrate  101 .  
         [0031]    If a process of removing or mitigating cracks and chips  105  of the glass substrate  101  is performed, it is expected that latent cracks can be prevented from being extended by a static load and the load resistance can be improved.  
         [0032]    On the basis of the experiment results that each break  106  does not terminate at the same side, it can be presumed that it is sufficient if a process of removing or mitigating cracks and chips is performed for three sides of a rectangular glass substrate. The process of removing or mitigating cracks and chips is no more necessary to be performed for the remaining one side.  
         [0033]    Such a process of reducing the effects of cracks and chips of a glass substrate is called a smoothing process (rough surface removing or mitigating process).  
         [0034]    [0034]FIG. 6D illustrates an experiment of applying a static load to a laminated glass substrate structure made of a pair of glass substrates adhered together. A pair of glass substrates  111  and  112  is adhered together at their peripheral areas, with a space being formed in the inside. The space between the glass substrates  111  and  112  is filled with liquid crystal and hermetically sealed.  
         [0035]    A static load F was applied down to the pair of laminated glass substrates  111  and  112 . A break was formed always first at the lower glass substrate  112  when the static load F was applied to the upper glass substrate  111  downward. As the laminated glass substrates  111  and  112  are bent by the static load F, the upper glass substrate  111  is applied with a compressive stress and bent while being compressed, whereas the lower glass substrate  112  is applied with a tensile stress and bent while being expanded. A break formed always first at the lower glass substrate  112  suggests that a glass substrate is weak against a tensile stress or bending tensile stress.  
         [0036]    Assuming that a static load is applied always in one direction, it is sufficient that countermeasures against a break of a laminated substrate are performed only for the substrate opposite to the side where a static load is applied. In other words, a resistance to a break can be improved if only the substrate to be applied with a tensile stress is reinforced.  
         [0037]    [0037]FIG. 6E illustrates how a static load applied to a single glass substrate works. As a static load F is applied to a single glass substrate  101 , the substrate  101  is bent. In this case, a main face  102   a  on which the static load is applied receives a stress with relatively high compression, whereas a main face  102   a  opposite to the static load applied side receives a stress with relatively high tensile. It can be expected therefore that the load resistance of the glass substrate  101  can be improved if the main face  102   b  to be deformed in an outward convex is reinforced, when considered in the unit of main face.  
         [0038]    Next, embodiments of the invention based upon the results of the above-described preliminary experiments will be described.  
         [0039]    [0039]FIGS. 1A and 1B are perspective views of laminated glass substrate structures according to embodiments of the invention.  
         [0040]    Referring to FIG. 1A, a pair of glass substrates  11  and  12  is adhered together at their opposing areas to form a laminated glass substrate structure  10 . Adhesion may be performed at their whole opposing areas or at their peripheral areas. The upper main face of the upper glass substrate  12  is defined by four edges e 21  to e 24 .  
         [0041]    It is assumed that the laminated glass substrate structure  10  receives a static load applied in a direction from the lower to upper. A smoothing process is performed for a peripheral area  14  along the four sides of the upper glass substrate  12 . The peripheral area  14  is a looped area along the four edges e 21  to e 24  defining the upper main face of the upper glass substrate  12 . The smoothing process is performed to the extent that the effects of rough surface such as cracks and chips on the edges e 21  to e 24  are sufficiently lowered.  
         [0042]    [0042]FIGS. 2A to  2 E are schematic partial plan views of a main face of a glass substrate, illustrating the smoothing process to be executed for edges of a glass substrate. Here, the smoothing process on an edge includes a process of treating only the edge and a process of treating a side face defining the edge. FIG. 2A shows a glass substrate  12  ( 11 ) before the smoothing process is executed. A side face including an edge eo of the glass substrate  12  before the smoothing process has a rough surface including small cracks and chips.  
         [0043]    [0043]FIG. 2B illustrates a smoothing process of mitigating a rough surface. An edge ea (and a side face defining the edge ea) after the smoothing process has a mitigated rough surface as compared to the edge eo (and the side face) before the smoothing process, and the rough surface of sharp edges and cracks is rounded. Such a smoothing process may be a heating/melting process. As the edge portion of the glass substrate  12  is heated and melted, convex areas are melted and flowed to a nearby area to fill concave areas. Therefore, the processed edge ea has a rounded rough surface.  
         [0044]    Similar rough surface mitigating effects can be obtained by a dissolving process using hydrofluoric acid, in place of the heating/melting process.  
         [0045]    [0045]FIG. 2C illustrates a chamfering process. An edge portion of a glass substrate is lapped or polished obliquely to form a lapped face P. The boundary between the lapped face P and the main face forms a new edge eb, and the boundary between the lapped face and the side face forms another edge ex. If the new edge eb, formed between the main face and the lapped face P formed through a chamfering process, is smooth, generation of a break of the glass substrate is suppressed. The effects of this lapped face P can be retained if the new edge eb has a more mitigated rough surface than the original edge eo. The larger a chamfer width (d 1  to d 4  in FIGS. 4D and 4E), the better, although it depends on a depth of cracks and chips. If a chamfer width is larger, a deeper rough surface can be removed, assuming that the chamfer angle is constant. The chamfer angle (θ1, θ2 in FIGS. 4D and 4E) may be set in the range from 180° to 90°. In practical use, the chamfer width may be 0.1 to 0.5 mm, more preferably 0.2 to 0.5 mm and the chamfer angle may be 120° to 150°.  
         [0046]    [0046]FIG. 2D illustrates a smoothing process in which one side face with a rough surface of a glass substrate  12  is lapped to form a flat side face. As the side face is lapped, the original edge eo is changed to a new edge ec. This process may be a process similar to the lapping process shown in FIG. 2C.  
         [0047]    The process described with FIGS. 2C and 2D may be performed by abrasion. Abrasion may be conducted by using ultraviolet laser, Co 2  laser or the like. With abrasion, a region radiated with energy such as laser light is sublimated without experiencing a liquid phase, and the surface can be exhausted or consumed like lapping or polishing.  
         [0048]    [0048]FIG. 2E illustrates a smoothing process through hard resin coating. Here, hard resin also includes a thermal or an optical setting resin. The side face of a glass substrate  12 , at least an area including an edge, is coated with hard resin  16 . The original edge eo is embedded in the hard resin  16  and a new edge en is formed. If the hard resin  16  can sufficiently suppress the rough surface effects of extending cracks, the load resistance of the glass substrate  12  can be improved. For example, the rough surface effects can be suppressed by coating polyimide.  
         [0049]    In the embodiment shown in FIG. 1A, the smoothing process is performed with respect to the four sides, along the four edges, of the glass substrate  12  with a rough surface. Presence of the peripheral area  14  subjected to such a smoothing process improves the resistance to a static load applied, from the lower to upper, to the laminated glass substrate structure  10 .  
         [0050]    A peripheral area of the lower glass substrate  11  may also be subjected to the similar smoothing process. In this case, the load resistance can be improved even if a static load is applied, from the upper to lower, to a laminated glass substrate structure.  
         [0051]    [0051]FIG. 1B illustrates another embodiment of the invention. This laminated glass substrate structure  10  has the same configuration as FIG. 1A. In this embodiment, the smoothing process is performed with respect to a peripheral area  15  excepting one side which forms an edge e 24 . If three sides of a rectangular substrate are subjected to the smoothing process, the load resistance can be improved even if the remaining one side is not subjected to the smoothing process, because a break terminating at the same side is not formed as described earlier.  
         [0052]    Similar to the case shown in FIG. 1A, the smoothing process may also be performed for a lower glass substrate  11 , like an upper glass substrate  12 . In this case, one side which is not subjected to the smoothing process may be the same side of the upper glass substrate  12  or a different side.  
         [0053]    [0053]FIGS. 3A to  3 D show a liquid crystal display according to an embodiment of the invention.  
         [0054]    As shown in FIG. 3A, the liquid crystal display has a laminated glass substrate structure  10  made of a lower glass substrate  11  and an upper glass substrate  12  adhered together. The size of the upper glass substrate  12  is smaller than that of the lower glass substrate  11 . The upper glass substrate  12  is adhered to the lower glass substrate  11  at the peripheral area, exposing some area of the lower substrate at the lower and right sides. A flexible print circuit board  24  is connected to an outer area along the lower and right sides of the lower glass substrate  11 . More generally, a connector is connected to the laminated glass substrate structure. In this case, the connector includes a flexible printed circuit (FPC), a tape automated bonding (TAB), a tape carrier package (TCP), and the like. Semiconductor integrated circuit (IC) blocks  25  are mounted on the intermediate areas between the flexible print circuit board  24  and the upper glass substrate  12 . An area  17  excepting an outer peripheral area of the upper glass substrate  12  forms a display screen. A liquid crystal injection port  18  is formed to inject liquid crystal into an inner space between the upper and lower glass substrates  12  and  11 . After the liquid crystal is injected, the injection port  18  is hermetically sealed.  
         [0055]    For example, a thin film transistor circuit is formed on the lower glass substrate  11 , and connection wires to a driver circuit for the transistor circuit are led to the areas at the lower and right sides which the upper glass substrate  12  does not cover. The upper glass substrate  12  is formed with, for example, a color filter structure. With this arrangement, the liquid crystal display can achieve a color display.  
         [0056]    [0056]FIG. 3B shows the cross sectional structure of the liquid crystal display, taken along lines B 1 -B 1  and B 2 -B 2  shown in FIG. 3A. IC  25  is disposed in the right side area of the lower glass substrate  11 , and the flexible print circuit board  24  is bonded to the area at the right of IC  25  via an anisotropic conductive film  27 . The anisotropic conductive film  27  has conductivity only in the vertical (thickness) direction and presents no conductivity in the in-plane direction.  
         [0057]    The upper glass substrate  12  is disposed in the right area of the lower glass substrate  11 . Between the upper and lower glass substrates  12  and  11 , a liquid crystal layer is formed which is not shown for the purpose of simplifying the drawings. Also, lead wires and thin film transistor structures on both the substrates are not shown. For general knowledge of a liquid crystal display, reference may be made to, for example, U.S. Pat. No. 5,473,455 which is incorporated herein by reference.  
         [0058]    C-chamfered faces  20  are formed at upper and lower edges of the lower glass substrate  11 . C-chamfering is performed over the whole lengths of the right and lower sides of the laminated glass substrate structure  10  (in fact on the lower substrate  11  only).  
         [0059]    [0059]FIG. 3C is a cross sectional view taken along line C 1 -C 1  shown in FIG. 3A. At this side, the side faces of the lower and upper glass substrates  11  and  12  adhered together are made flush with each other, forming a common side face. C-chamfered faces are formed over the whole length of this side of the laminated glass substrate structure. Namely, chamfering is performed at this side only for the outside edge of each of the glass substrates  11  and  12  where there is the upper substrate.  
         [0060]    Although C-chamfering is performed both in FIGS. 3B and 3C, chamfering may be performed only along the lower edge. If a difference of processes between C-chamfering and chamfering for only the lower edge is not so large, it is preferable to perform C-chamfering.  
         [0061]    [0061]FIG. 3D is a cross sectional view taken along line D 1 -D 1  shown in FIG. 3A. This side has the injection port  18  so that if a mechanical process such as lapping is performed, the injection port  18  may be damaged. Therefore, the smoothing process is not performed for this side. A smoothing process through hard resin coating may be performed for this side.  
         [0062]    In the liquid crystal display shown in FIGS. 3A to  3 D, among the four edges defining the lower main face of the lower glass substrate, the three edges are formed with the chamfered faces  20  and  21 , and the remaining edge is not formed with a chamfered face.  
         [0063]    Of the four edges defining the upper main face of the upper glass substrate  12 , although one edge is formed with the chamfered face  21 , the other edges are not formed with a chamfered face. This chamfered face at a single edge was formed as a by-product of the chamfering process for the lower glass substrate.  
         [0064]    [0064]FIGS. 4A to  4 D illustrate the main processes of a method of manufacturing a liquid crystal display such as shown in FIGS. 3A to  3 D.  
         [0065]    As shown in FIG. 4A, a lower substrate  11  is prepared. A thin film transistor circuit  21  is formed on the display screen of the lower substrate  11 . The thin film transistor circuit can be formed by a known method. Although the glass substrate  11  having a size matching a single liquid crystal display is shown, a predetermined area of a large single plate of glass may be used as the glass substrate  11  at this process.  
         [0066]    As shown in FIG. 4B, an upper glass substrate  12  is prepared. A color filter array  22  is formed on the upper glass substrate  12 . The color filter array  22  can be formed by a known method.  
         [0067]    As shown in FIG. 4C, the upper glass substrate  12  is adhered to the lower glass substrate  11 . A display screen  17  is defined by an area excepting the peripheral adhesion area of the upper glass substrate  12 . In the area of the display screen, the thin film transistor circuit  21  is disposed on the lower substrate  11  and the color filter array  22  is disposed on the upper substrate  12 . Between the thin film transistor circuit  21  and color filter array  22 , a liquid crystal layer is formed. Liquid crystal can be injected through an injection port formed, for example, at the upper or left side of the laminated glass substrate structure. A process of injecting liquid crystal may be a known surface tension method, a known vacuum injection method, or the like.  
         [0068]    As shown in FIGS. 4D and 4E, after the upper glass substrate  12  is adhered to the lower glass substrate  11 , the laminated glass substrate structure is subjected to a chamfering process.  
         [0069]    [0069]FIG. 4D illustrates a chamfering process for the common side face formed by the lower and upper glass substrates  11  and  12 . A lapping tool  13  is used for performing C-chamfering. The lower edge portion of the lower glass substrate  11  and the upper edge portion of the upper glass substrate  12  are chamfered.  
         [0070]    The thickness t 1  of the upper glass substrate  12  and the thickness t 2  of the lower glass substrate  11  are both about 0.7 mm. The chamfer width d 1  of the upper glass substrate  12  and the chamfer width d 2  of the lower glass substrate  11  are both about 0.1 mm to 0.5 mm. The angles θ1 and θ2 between the chamfered faces and main faces are about 135° to 150°, for example.  
         [0071]    [0071]FIG. 4E illustrates C-chamfering at the area where the upper glass substrate  12  does not exist. Since the upper glass substrate  12  does not exist in this area, C-chamfering is performed with respect to the lower glass substrate  11 . The chamfer width d 3  on the upper main face side and the chamfer width d 4  on the lower main face side are equal to the chamfer widths d 1  and d 2  shown in FIG. 4D. The chamfer angles θ3 and θ4 are also equal to the chamfer angles θ1 and θ2 shown in FIG. 4D.  
         [0072]    After the chamfering process, IC and a flexible print circuit board such as shown in FIG. 3A are mounted if necessary on the laminated glass substrate structure.  
         [0073]    Although the chamfering process is used as the smoothing process in the above, other smoothing processes illustrated in FIGS. 2B to  2 E may also be selectively used.  
         [0074]    [0074]FIG. 5 shows the experiment results of various smoothing processes, including measured load resistances of liquid crystal displays using laminated glass substrate structures. The structure of each sample is schematically illustrated in the lower portion of this table.  
         [0075]    Sample S 1  had a conventionally known structure, with only the areas exposing the lower glass substrate at two sides being subjected to chamfering.  
         [0076]    Sample S 2  was subjected to chamfering at lower four sides of the lower glass substrate.  
         [0077]    Sample S 3  was subjected to chamfering at three sides of the lower glass substrate, excepting the side formed with an injection port.  
         [0078]    Sample S 4  was subjected to chamfering at the two sides same as Sample S 1  and also to smoothing thorough hard resin coating at all four sides.  
         [0079]    Sample S 5  was subjected to chamfering at the two sides same as Sample S 1  and also to smoothing thorough hard resin coating at one of the remaining two sides excepting the side formed with an injection port.  
         [0080]    Sample S 6  was subjected to chamfering at the two sides same as Sample S 1  and also to smoothing through hard resin coating at the side formed with an injection port.  
         [0081]    Of Samples S 2  to S 6  formed by the embodiment methods, Samples S 2  and S 4  were subjected to the smoothing process at all four sides of the lower glass substrate, and Samples S 3 , S 5  and S 6  were subjected to the smoothing process at three sides among the four sides.  
         [0082]    Values shown in the table indicate loads when a break was formed at the lower glass substrate as a static load was applied to the liquid crystal displays using the laminated glass substrate structures, from the display screen side. None of Samples had a break at the upper glass substrate before a break at the lower glass substrate was formed. Many of Samples S 1  with chamfering only at two sides as in a conventional manner had a break at a static load of less than 10 Kg weight, meaning insufficient static load resistance.  
         [0083]    In contrast, all other samples S 2  to S 6  had a load resistance of 10 Kg weight or larger. It can be said that the static load resistance was improved sufficiently.  
         [0084]    Although a decision cannot be definitely made because of a wide distribution of values of measured static load resistances, it can be said that the static load resistance of Sample S 2  in particular, which was subjected to chamfering at all four sides of the lower glass substrate, is excellent. As compared with Sample S 4  with the smoothing process at all four sides, the experiment results of Samples S 3 , S 5  and S 6  with the smoothing process only at three sides imply that the same or similar effects as the smoothing process at four sides can be expected for the smoothing process even at three sides.  
         [0085]    The present invention has been described in connection with the preferred embodiments. The invention is not limited only to the above embodiments. For example, similar effects of the smoothing process will be obtained also by other laminated glass structures such as plasma display panels. It is apparent that various modifications, improvements, combinations, and the like can be made by those skilled in the art.