Patent Document

BACKGROUND OF THE INVENTION 
     The present invention relates to a liquid crystal panel, a liquid crystal panel cutting method, a liquid crystal panel cutting apparatus and a liquid crystal display device employing the liquid crystal panel. 
     According to a first prior art techniques as disclosed in Japanese Patent Laid-open No. Hei 7-100799 cuts a liquid crystal panel is cut for a word processor or the like by pressing a rotary blade having a cutting edge of an acute angle nearly equal to a right angle against the liquid crystal panel, and removes a part of the liquid crystal panel on one side of a groove is removed and a crack formed by pressing the rotary blade against the liquid crystal panel by applying an impulsive force to the part of the liquid crystal panel, applying a thermal shock to the liquid crystal panel by heating the liquid crystal panel by a hot plate or applying impulsive vibrations to the liquid crystal panel by a vibrating device. 
     When the crack cannot be satisfactorily formed, the first prior art technique needs to apply a high shock to the liquid crystal panel. Particularly, when the substrate is a liquid crystal panel formed by combining a top substrate and a bottom substrate, electrodes disposed between the top and the bottom substrate and a sealing resin, stress is induced around the electrodes and the sealing resin when a shock is applied to the liquid crystal panel. Consequently, defects including separation of the sealing resin from the substrates and undesirable breakage off the cutting line are liable to occur. There is the possibility that methods using heat or impulsive vibrations practice the deterioration of durability and performance. 
     Cutting a liquid crystal panel for a liquid crystal display device is very difficult as compared with cutting a glass plate because the glass substrate comprises a thin glass plate of a thickness of 1 mm or below, and a film of a material softer than glass formed on the thin glass plate. Flexible conductive lines must be affixed to a part of the glass substrate in the vicinity of a cut edge. When the liquid crystal panel is cut mechanically according to the first prior art technique which forms a crack in the liquid crystal panel, the cut liquid crystal panel has a sharp edge, and there is the possibility that the flexible conductive lines that touch the sharp edge of the liquid crystal panel are cut by the sharp edge. 
     According to a second prior art technique as disclosed in Japanese Patent Laid-open No. Hei 6-305759 a liquid crystal panel has a cut edge formed by cutting the liquid crystal panel by means of a chamfering tool to exclude the possibility. 
     However, the second prior art technique needs an additional chamfering process and additional time. 
     Both the first and the second prior art technique are able to cut a liquid crystal panel only along a straight line in a rectangular shape and are incapable of cutting liquid crystal panels in curvilinear shapes to form liquid crystal panel for use on word processors, calculators, traffic signs, toys and illuminations. Thus, the first and the second prior art techniques are inferior in freedom of design. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is a first object of the present invention to provide a liquid crystal panel capable of preventing damaging flexible conductive lenses without requiring time and labor. A second object of the present invention is to provide a liquid crystal panel cutting method capable of preventing damaging flexible conductive lines by a cut edge of the liquid crystal panel without requiring an additional chamfering process. A third object of the present invention is to provide a liquid crystal panel cutting apparatus capable of carrying out the liquid crystal panel cutting method meeting the second object and of cutting the liquid crystal panel in a curvilinear shape. A fourth object of the present invention is to provide a liquid crystal display device employing the liquid crystal substrate meeting the first object. 
     A first invention to achieve the first object is a liquid crystal panel comprising a glass substrate cut with a water jet. According to the first invention, when cutting a liquid crystal panel with a water jet as shown in FIGS. 16A and 16B, an edge of an end surface of a glass substrate  31  of the liquid crystal panel is broken into particles  201  of a material forming the edge by the impingement of droplets  200  of a water jet  39  jetted through a nozzle  52  thereon. Therefore, the edge of the end surface is rounded without requiring a chamfering progress and hence damaging flexible conductive lines by the edge of the end surface of the glass substrate can be prevented. 
     A second invention to achieve the second object is a liquid crystal panel cutting method that cuts a liquid crystal panel by repeatedly blasting liquid droplets or abrasive against a component glass substrate of the liquid crystal panel to crush part of the glass substrate by the impact energy of the liquid droplets or the abrasive. According to the second invention, a liquid crystal panel is cut by repeatedly blasting liquid droplets or abrasive against a component glass substrate of the liquid crystal panel to crush part of the glass substrate by the impact energy of the liquid droplets or the abrasive. The edge of an end surface of the glass substrate is rounded by the impact applied thereto by the liquid droplets or the abrasive. Therefore, flexible conductive lines will not be damaged even if the same come into contact with the edge of the end surface of the glass substrate. 
     A third invention to achieve the fourth object is a display provided with a liquid crystal panel as a display means, in which the liquid crystal panel has a glass substrate cut with a water jet. According to the third invention, the liquid crystal panel of the display hardly capable of damaging the flexible conductive lines improves the reliability of the display. 
     A fourth invention to achieve the third object is a liquid crystal panel cutting apparatus comprising a pressure increasing means for increasing the pressure of a liquid, a nozzle provided with a throat that receives the liquid of a pressure produced by the pressure increasing means; a nozzle moving means supporting the nozzle so as to be movable at least in a plane parallel to the liquid crystal panel, and a table supporting the liquid crystal panel. According to the fourth invention, the pressure of the liquid is raised by the pressure increasing means, the liquid is supplied to the nozzle, the flow of the liquid is restricted by the throat and the velocity of the liquid is increased to produce a jet, the jet is applied to the glass substrate of the liquid crystal panel supported on the table, the material of the glass substrate is crushed into particles and removed by the impact energy of the jet of the liquid to cut the glass substrate, and the edge of the cut end surface is rounded by the impact of the liquid thereon to prevent damaging flexible conductive lines when the same touches the edge of the edge surface of the glass substrate. The nozzle is moved in the plane parallel to the liquid crystal panel by the nozzle moving means to cut the liquid crystal panel along a cutting line including curves to form the liquid crystal panel in a desired shape. Thus, the liquid crystal can be formed in a shape of a desired design. 
     According to a fifth invention, in the liquid crystal panel cutting apparatus according to the fourth invention, the nozzle is provided with an abrasive feed port, and an abrasive fed device for feeding the abrasive is connected to the abrasive feed port to feed the abrasive to the nozzle. The fifth invention has, in addition to the working effects of the fourth invention, a working effect of blasting the abrasive at a high velocity against the glass substrate to crush and remove the material of the glass substrate. Therefore, the glass substrate can be efficiently cut, and the glass substrate can be cut even if the same has a high strength. 
     According to a sixth invention, in the liquid crystal panel cutting apparatus according to the fourth invention, a plurality of nozzles similar to the foregoing nozzle are supported by a nozzle moving means. Thus, the sixth invention has, in addition to the working effect of the fourth invention, a working effect of simultaneously cutting a plurality of liquid crystal panels corresponding to the plurality of nozzles. Thus, the liquid crystal panel cutting apparatus is suitable for the mass production of liquid crystal panels. 
     According to a seven invention, in the liquid crystal panel cutting apparatus according to the fourth invention, the liquid in water, alcohol, aceton or kerosene. Thus the seventh invention has, in addition to the working effect of the fourth invention, a working effect of using a liquid selectively determined according to the property of the liquid crystal panel for cutting the liquid crystal panel to suppress the reduction of the strength of the liquid crystal panel to the utmost. 
     According to an eighth invention, the liquid crystal panel cutting apparatus according to any one of the fourth to the seventh invention further comprises a liquid tank capable of containing the liquid in a depth great enough to immerse the table, the liquid crystal panel, and the nozzle or the nozzles entirely in the liquid, and the table is disposed in the liquid tank so as to be submerged by the liquid. The eighth invention has, in addition to the working effect of any one of the fourth to the seventh invention, a working effect to cut the liquid crystal panel by the jet jetted by the nozzle immersed in the liquid contained in the liquid tank so as to impinge on the liquid crystal panel, leakage of dust produced by the cutting work and noise generated by the cutting work outside the liquid tank can be suppressed. Significant cavitation occurs in the liquid by the jet jetted from the nozzle and cavitation improves cutting efficiency. 
     According to a ninth invention, the liquid crystal panel cutting apparatus according to any one of the fourth to the seventh invention further comprises a splash guard surrounding the nozzle so as not to block off the path of the jet of the liquid between the nozzle and the liquid crystal panel. The ninth invention has, in addition to the working effect of any one of the fourth to the seventh invention, a working effect to suppress the scatter of chips and particles produced by cutting work to the utmost by the splash guard. 
     According to a tenth invention, the liquid crystal panel cutting apparatus according to any one of the fourth to the seventh invention further comprises auxiliary nozzles arranged around the nozzle so as not to block at least a path of the jet of the liquid between the nozzle and the liquid crystal panel, and a liquid source connected to the auxiliary nozzles to supply a liquid of a pressure that will not damage the liquid crystal panel to the auxiliary nozzles. The tenth invention has, in addition to the working effect of any one of the fourth to the seventh invention, a working effect of suppressing the scatter of chips and particles produced by the cutting work by surrounding a region in which the cutting work is carried out by jets jetted from the auxiliary nozzles during the cutting work. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a front elevation of a word processor provided with a liquid crystal display device according to the present invention. 
     FIGS. 2A and 2B are a front elevation and a side elevation, respectively, of a liquid crystal panel included in the liquid crystal display device shown in FIG.  1 . 
     FIG. 3 is a sectional view of liquid crystal panels of assistance in explaining a cutting work according to the present invention. 
     FIG. 4A is a front elevation of an internal arrangement of a traffic signal employing liquid crystal panels according to the present invention. 
     FIG. 4B is a front elevation of a case of the traffic signal shown in FIG.  4 A. 
     FIG. 5 is a general view of a cutting apparatus according to the present invention. 
     FIG. 6 is an enlarged sectional view of a nozzle included in the cutting apparatus shown in FIG.  5 . 
     FIGS. 7A,  7 B and  7 C are sectional views of nozzles applicable to the cutting apparatus shown in FIG.  5 . 
     FIG. 8 is an enlarged perspective view of an articulated arm included in the cutting apparatus shown in FIG.  5 . 
     FIG. 9 is a side elevation of another articulated arm that can be employed in the cutting apparatus according to the present invention. 
     FIG. 10 is a side elevation of a third articulated arm that can be employed in the cutting apparatus according to the present invention. 
     FIG. 11 is a schematic sectional view of a nozzle that can be employed in the cutting apparatus according to the present invention and provided with an abrasive feed system. 
     FIG. 12A is a perspective view of a nozzle unit having two nozzles and a high-pressure hose for a cutting apparatus according to the present invention. 
     FIG. 12B is a perspective view of nozzle unit having two nozzles and two high-pressure hoses for a cutting apparatus according to the present invention. 
     FIG. 12C is a side elevation of assistance in explaining the relation between two nozzles and liquid crystal panels. 
     FIG. 13 is a sectional view of a nozzle provided with auxiliary nozzles for a cutting apparatus according to the present invention. 
     FIG. 14 is a sectional view of a nozzle provided with a splash guard for a cutting apparatus according to the present invention. 
     FIG. 15 is a front elevation of components of a cutting apparatus according to the present invention that carries out cutting work in a liquid. 
     FIG. 16A is a view of assistance in explaining a cut part of a glass plate cut with a water jet. 
     FIG. 16B is an enlarged view of a part A of FIG.  16 A. 
    
    
     DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a word processor provided with a display device  1  including a liquid crystal panel in a preferred embodiment according to the present invention cut with a water jet. The word processor comprises the display device  1 , a power supply  2 , an input unit  3 , a storage device  4  and an arithmetic unit  5 . 
     Referring to FIGS. 2A and 2B, a liquid crystal panel  21  included in the display device  1  has a liquid crystal driving circuit  22  connected to driving electrodes  35  formed by edging on a glass substrate  31  by flexible conductive lines  24 . 
     FIG. 3 is a view of assistance in explaining a cutting operation for cutting the lower glass substrate  31  provided with the driving electrodes  35  with a water jet  39  jetted through a nozzle  52 . Upper glass substrates  31  and the lower glass substrate  31  are coated with polarizing films  32 . A liquid crystal  33  is sealed in a space defined by each upper glass substrate  31 , the lower glass substrate  31  and a sealing resin  36 . It is very difficult to cut a workpiece thus formed because the workpiece is formed by assembling members of different materials. However, the workpiece can be effectively cut with the water jet because the water jet is excellent in cutting members of different materials. 
     Corner edges of end surfaces of the liquid crystal panel cut with the water jet  39  is not as sharp as the edges of end surfaces of the same cut with a rotary glass cutter called a router. Thus, the edge of an end surface of the lower glass substrate  31  is rounded as shown in FIGS. 16A and 16B and hence there is no possibility that the flexible conductive lines  24  attached to a peripheral part of the liquid crystal panel  21  as shown in FIGS. 2A and 2B so as to be connected to the driving electrodes  35  are broken when the same come into contact with the edges of the lower glass substrate  31   a.  Therefore, the flexible conductive lines can be folded along the cut surfaces to form the display device in compact construction and the display device has high reliability. 
     FIGS. 4A and 4B show a traffic signal provided with liquid crystal panels of a desired shape embodying the present invention. The traffic signal comprises liquid crystal panels  41 , liquid crystal driving circuits  42 , a case  43 , a power supply unit  44  and an arithmetic unit  45 . Whereas the liquid crystal panel  21  is rectangular, the liquid crystal panels  41  are circular. 
     Since the liquid crystal panels  41  can be formed in a circular shape instead of a rectangular shape, the liquid crystal panels  41  can be arranged in a relatively narrow space and a compact indicating unit can be formed. 
     Voltage necessary for driving a liquid crystal display, differing from that for driving a LED display, may be low. A traffic signal of the same construction can be manufactured. Indications on a traffic sign employing a liquid crystal panel can be changed simply by changing a program for controlling an internal driving device, and signs can be mass-produced at low costs. 
     A liquid crystal panel formed in a desired shape by cutting can be applied not only to the foregoing products, but also to toys, illuminations and amusement articles. Since the liquid crystal panel can be cut in an optional shape, the liquid crystal panel can be applied to various articles of different designs. 
     FIG. 5 shows a liquid crystal panel cutting apparatus that uses a water jet. The liquid cutting panel cutting apparatus comprises the following components. 
     The liquid crystal panel cutting apparatus comprises a high-pressure pump  51  for pumping water at a high pressure, a nozzle  52  provided with a throat to jet water, a high-pressure hose  53  connecting the high-pressure pump  51  and the nozzle  52 , a articulated hand  54  capable of moving the nozzle  52  to a position corresponding to an optional position on a liquid crystal panel (hereinafter, a liquid crystal panel will be referred to as a “workpiece”), a purifying tank  55  for supplying water to the high-pressure pump and purifying recovered water to use the same again, a reservoir tank  56  for storing water returned from the purifying tank  55 , a conveyors  57  for conveying the workpiece, a table  58  placed on the conveyor  57  to hold the workpiece fixedly thereon, a controller  59  for controlling those components, and partitions  60  for preventing water splash from scattering. 
     The components will be described in detail. The high-pressure pump  51  applies an increased pressure to water supplied from the reservoir tank  56  by a pressure intensifier to supply high-pressure water through the high-pressure hose  53  to the nozzle  52 . The high-pressure water is jetted through the nozzle  52  in a jet of water against the workpiece supported on the table  58 . The workpiece is subjected to a pretreatment at a pretreatment station, is conveyed by the conveyor  57  onto the table  58 . The workpiece is fixedly held on the table  58  during a process by a vacuum chuck or a chucking jig. After the completion of the process, the workpiece is released from the table  58  and is carried away by the conveyor  57  in a direction opposite a direction in which the workpiece is conveyed to the table  58 . Thus, cutting work can be carried out by a continuous processing system instead of a batch processing system. During the cutting work, the table  58  is surrounded by the partitions  60  to prevent the water jet and particles of the workpiece produced by processing from scattering. The water used for the cutting work is purified in the purifying tank and the purified water is returned to the reservoir tank  56  to use the same again. 
     Basically, water for the cutting work is pure water. Some glass is affected by water and reduces its strength when exposed to water. When processing a workpiece of such a glass, alcohol, aceton or kerosene is used instead of water. Thus, workpieces of glass that need to be kept away from water can be cut without reducing their strength. 
     FIG. 6 shows a nozzle that jets a water jet. A nozzle  61  has a coupling part  63  to be coupled with a high-pressure hose  62 , and a throat  64  defining a passage of a reduced sectional area. 
     The throat  64  causes a static pressure degradation in high-pressure water  65  and increases the velocity of the fluid. The throat  64  enables a water jet  39  top issue straight therefrom and to reach a distant object. The velocity of the water jet  39  at the outlet  65  of the nozzle is far higher than the velocity of sound and the water jet  39  is capable of cutting an object. Preferably, the discharge pressure of the high-pressure pump  61  is in the range of 50 to 300 MPa, more preferably, in the range of 200 to 300 MPa. 
     FIGS. 7A,  7 B and  7 C show nozzles for jetting a liquid jet. All the nozzles shown in FIGS. 7A,  7 B and  7 C is provided with a throat  64  to jet a liquid jet so as to travel straight at a high velocity to a distant position. The nozzle shown in FIG. 7A is provided with a single-stage throat  64 . The nozzle shown in FIG. 7C is provided with a plurality-stage throat  64  and is able to increase the velocity of the liquid jet more effectively than the nozzle provided with a single-stage throat. The liquid jet jetted by the nozzle shown in FIG. 7C shortens the time necessary for cutting. The nozzle shown in FIG. 7B has a coupling part  63 , a throat  64  continuous with the coupling part  63 , and a flaring part  94  having a taper space expanding from the forward end of the throat  64 . The nozzle shown in FIG. 7B is capable of jetting a water jet and of producing cavitation that promotes cutting. 
     FIG. 8 shows a nozzle moving mechanism capable of optionally moving a nozzle  91  relative to a workpiece, of keeping an appropriate distance between the tip of the nozzle and the workpiece and of moving the nozzle  91  to form the workpiece in a desired shape. 
     An X-axis bar  105  is fixed to a fixed frame  110  set on the floor of a cutting workshop. A ball screw  103   b  has a threaded rod supported for rotation on the X-axis bar  106  so as to be driven for rotation by a motor  106 , and a slider  107  linked to the threaded rod for movement along the X-axis bar  105 . 
     A Y-axis bar  108  is attached to the slider  107  so as to extend horizontally and perpendicularly to the X-axis bar  105 . A ball screw  103   c  is mounted on the Y-axis bar  108  and is driven by a motor  109 . 
     The ball screw  103   c  has a slider  104  which is driven for sliding along the Y-axis bar  108  by a threaded rod. 
     A Z-axis bar  101  is combined with the slider  104  so as to be vertically movable. A ball screw  103   a  is mounted on the Z-axis bar  101  and is driven for rotation by a motor  102 . The ball screw  103   a  has a slider  104  and a threaded rod linked to the slider  104 . 
     When the threaded rod of the ball screw  103   b  is driven for rotation by the motor  106 , the slider  107  is moved along the X-axis. When the threaded rod of the ball screw  103   c  is driven for rotation by the motor  109 , the slider  104  moves along the Y-axis. Thus, the nozzle  52  attached to a lower end part of the Z-axis bar  101  can be moved in a two-dimensional space, i.e., a plane. 
     When the threaded rod of the ball screw  103   a  is driven for rotation by the motor  102 , the Z-axis bar  101  combined with the slider  104  moves vertically together with the motor  102  and the ball screw  103   a.    
     Thus, the nozzle  52  can be moved along the Z-axis. Consequently, the nozzle  52  can be moved in a three-dimensional space. 
     The nozzle  52  is moved along the Z-axis to adjust properly the distance between the liquid crystal panel and the tip of the nozzle  52  during cutting work. The nozzle  52  is moved along the X-axis and the Y-axis to move the nozzle  52  along a curve to cut the liquid crystal panel in a curvilinear shape. 
     FIG. 9 shows another nozzle moving mechanism for moving a nozzle  52  to an optional position. The nozzle moving mechanism moves the nozzle  52  in a cylindrical coordinate system defined by r, Z and θ. An articulated arm unit having arms  111  is mounted on a swivel base  112   a.  The swivel base  112   a  is turned by a driving unit  112  to run the articulated arm unit having the arms  111  in a horizontal plane through an angle θ. The arms  111  of the articulated arm unit can be turned in a vertical plane by driving devices  113  to move the nozzle  52  along the Z-axis and the r-axis. The nozzle  52  is kept in a vertical position. Thus, the nozzle  52  can be moved to an optional position in a three-dimensional space. 
     FIG. 10 shows a third nozzle moving mechanism for moving a nozzle  52  to an optional position. The nozzle moving mechanism moves the nozzle  52  in a cylindrical coordinate system defined by r, Z and θ. A post  121  is set up on a swivel base  112   a.  The swivel base  112   a  is turned in a horizontal plane by a driving mechanism  123  to turn components including the nozzle  52  and supported on the swivel base  112   a  through an optional angle θ. A slider  125  is combined with the post  121  and is moved vertically along the post  121  by a rack-and-pinion driving mechanism  124  to move the nozzle  52  along the Z-axis to an optional position. A parallel crank mechanism includes links  127 , a nozzle holding member  128  and a slider  125 . The links  127  are supported on the slider  125  so as to be turned in a vertical plane by driving mechanisms  126 . The nozzle  52  connected to the lower end of the nozzle holding member  128  can be moved in directions parallel to the r-axis to an optional position by turning the links  127  in a vertical plane. The nozzle  52  held in a vertical position can be moved to an optional position in a three-dimensional space. 
     The nozzle may be held by any nozzle moving mechanism other than those mentioned above; the nozzle may be held by any suitable nozzle moving mechanism including a nozzle holding member, an articulated armor a linkage combined with the nozzle holding member, and driving mechanisms for driving those components. 
     The nozzle can be held at an appropriate distance from the workpiece at all times by the foregoing mechanism. Preferably, tip-to-work distance, i.e., the distance between the tip of the nozzles and the workpiece, is in the range of 1 to 5 mm, more preferably, in the range of 1 to 2 mm. The nozzle can be positioned at an appropriate distance from the workpiece by moving the same in directions along the Z-axis by any one of the nozzle moving mechanisms shown in FIGS. 8,  9  and  10 . 
     The workpiece can be cut in an optional curvilinear shape, such as a circular shape or a heart shape by moving the nozzle  52  in a three-dimensional space or at least in a horizontal plane. Thus, the present invention is applicable to cutting liquid crystal panels for toys, traffic signals, traffic signs, advertising lamps and the like. 
     FIG. 11 shows an embodiment provided with a nozzle  52  that issues a water jet, an abrasive supply system, and a nozzle  131  connected to a forward end part of the nozzle  52  and capable of issuing high-pressure water containing an abrasive. A jet issued from the nozzle  52  flows into the nozzle  131 , and an abrasive  132  is supplied from a hopper  133  to a position between the nozzles  52  and  131 . The abrasive is mixed in the water jet  39  by a negative pressure produced by the jet. The water jet  39  containing the abrasive is jetted through the nozzle  131  against a workpiece. The abrasive is supplied at a supply rate in the range of 50 to 150 gf/min, more preferably, at a supply rate of 150 gf/min. 
     FIGS. 12A,  12 B and  13 C shows cutting apparatus embodying the present invention each provided with a plurality of nozzles that issue a water jet. The cutting apparatus shown in FIG. 12A has a pipe  142  connected to a high-pressure hose  53  and having closed opposite ends, and two nozzles  52  attached to the pipe  142 . A liquid supplied through the high-pressure hose  53  into the pipe  142  is issued through the two nozzles  52  in water jets to cut two parts of a workpiece simultaneously. The cutting apparatus shown in FIGS. 12A,  12 B and  12 C is the same in other respects as that shown in FIG.  5 . 
     In a cutting apparatus shown in FIG. 12B, two high-pressure hoses  53  are connected to a high-pressure pump  51 , two nozzles  52  are connected to the high-pressure hoses  53 , respectively, and the two nozzles  52  are connected by a member  100  having a rigidity high enough to keep the nozzles  52  spaced a predetermined distance apart. A liquid supplied through the high-pressure hoses  53  is issued through the two nozzles  52  in water jets to cut two parts of a workpiece simultaneously. The cutting apparatus shown in FIGS. 12A,  12 B and  12 C is the same in other respects as that shown in FIG.  5 . 
     FIG. 12C shows the positional relation between a plurality of nozzles  52  and a workpiece. The pipe  142  or the member  100  is held by the articulated arm  54  shown in FIG. 5 so as to be movable in a three-dimensional space, the plurality of nozzles  52  are located above liquid crystal panels  21  fixedly mounted on a table  58 , water jets are issued simultaneously through the plurality of nozzles  52  to cut the plurality of liquid crystal panels  21  simultaneously. Consequently, processing time can be reduced. 
     FIG. 13 is a sectional view of a composite jetting apparatus that prevents the scatter of particles produced when a workpiece is cut and an abrasive mixed in high-pressure water. The composite jetting apparatus issues auxiliary jets of a velocity lower than that of a main jet so as to surround the main jet. 
     Auxiliary nozzles  162  are arranged so as to surround a main nozzle  151 . A high-pressure hose  53  is connected to the main nozzle  161 . An abrasive supply pipe  166  is connected to a mixer  165  connected to the main nozzle  161 . An abrasive is mixed in high-pressure water by the mixer  165  and high-pressure water containing the abrasive is jetted through the main nozzle  161 . Low-pressure water jets issued from the auxiliary nozzles  161  prevents the scatter of water containing the abrasive. 
     FIG. 14 is a sectional view showing a cover covering a part of a workpiece being processed to prevent the scatter of particles produced when the workpiece is cut and an abrasive mixed in high-pressure water. 
     A nozzle  52  jetting a water jet  39  against a liquid crystal panel  21  is surrounded by a cover  172 . 
     The scatter of particles produced when the liquid crystal panel  21  is processed or an abrasive contained in the water jet is prevented by the cover  172 . 
     FIG. 15 shows the table  58  and a part of the conveyor  57  and the nozzle  52  of the apparatus shown in FIG. 5 immersed in a liquid in a liquid tank  182 . A liquid crystal panel is fixed to the table  58  immersed in a depth D of the liquid, a water jet is issued through the nozzle  52  against the liquid crystal panel to cut the liquid crystal panel as mentioned in connection with FIG.  3 . The apparatus is the same in other respects as the apparatus shown in FIG.  5 . When cutting the liquid crystal panel immersed in water, cavitation is induced by the water jet issued from the nozzle  52 , energy generated by the collapse of cavitation contributes to cutting the glass substrate, improves cutting efficiency and hard glass substrates can be easily cut.

Technology Category: 3