Abstract:
The present invention provides a finely-divided powder spray apparatus having a spray nozzle pipe for discharging spacers for liquid crystal displays from the tip together with a gas flow, which is disposed at a prescribed distance from a member to be sprayed, and comprising:  
     a touch panel which enters control factors for controlling the moving-speed of the tip of the spray nozzle pipe at individual spray points on the surface of the glass substrate; and  
     an actuator driver which controls the moving-speed of the tip of the spray nozzle pipe in accordance with the control factor entered by the touch panel.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a finely-divided powder spray apparatus for discharging finely-divided powders together with a gas stream so that the powders are sprayed onto a member to be sprayed as a substrate.  
         BACKGROUND OF THE INVENTION  
         [0002]    A spacer spray apparatus is known as a representative example of finely-divided powder spray apparatuses, the apparatus uniformly spraying a prescribed amount of spacers for liquid crystal displays (spacer beads) as the finely-divided powders having a uniform particle size between substrates constituting a liquid crystal display panel for liquid crystal display devices, for example, between a glass substrate and a glass or plastic substrate so that the spacers are formed into a single layer.  
           [0003]    In the liquid crystal display panel of a liquid crystal display device and the like, particles (spacer beads such as plastic particles and silica particles) having a uniform particle size of about several microns to several tens of microns are sprayed or coated as spacers as uniformly as possible in an amount of 10 to 2000 particles per unit area of 1 mm 2  to form a single layer between substrates, for example, between glass substrates, between plastic (organic glass, etc.) substrates other than the glass substrates, and between the plastic substrate and the glass substrate, (hereinafter the glass substrate will be described as a representative example and the aforementioned member to be sprayed are simply referred to as the glass substrate as a whole) so that the space to charge liquid crystals is formed.  
           [0004]    Some conventional spacer spray apparatuses spray spacer particles onto the glass substrate by transporting the fine spacer particles together with a gas flow of air, nitrogen, etc., through a thin pipe (transportation pipe) and discharging the particles from a swinging spray nozzle pipe together with the gas stream. The spacer particles are finely-divided powders having a size of several microns to several tens of microns, and liable to float. They are various types of plastic particles or silica particles, and liable to be charged. Therefore, it is difficult to spray the spacers onto the glass substrate at a prescribed density with excellent repeatability. These apparatuses can charge the spacer particles in accordance with a charged polarity (electrostatic polarity) and ground the glass substrate and a table so as to reliably spray the spacer particles onto the glass substrate at the prescribed density.  
         SUMMARY OF THE INVENTION  
         [0005]    Recently, the size of a liquid crystal display panel has been increased gradually and a plurality of liquid crystal display panels have often been made of a single glass substrate. It is therefore required to fix a larger glass substrate on a table disposed in a chamber of the spacer spray apparatus. In general, the glass substrate is fixed onto the table by vacuuming the substrate from the side of the table. However, the density of the spacers deposited at one spot, where the glass substrate is fixed, is different from the densities at other spots depending on a strength of vacuuming the glass substrate, i.e., the spacers cannot be uniformly sprayed. Further, if a difference in electric field strengths generates on the surface on the glass substrate, the spacers cannot be uniformly sprayed out in some cases.  
           [0006]    An object of the present invention is to provide a finely-divided powder spray apparatus which can adjust a density of finely-divided powders such as spacers for liquid crystal displays to be sprayed onto a member such as a glass substrate.  
           [0007]    The finely-divided powder spray apparatus of the present invention having a spray nozzle pipe for discharging the finely-divided powders from the tip together with a gas stream, which is disposed at a prescribed distance from a member to be sprayed, and comprising:  
           [0008]    a moving-speed control factor entry means which enters moving-speed control factors for controlling a moving-speed of the spray nozzle pipe in a prescribed area of the surface of the member to be sprayed; and  
           [0009]    a moving-speed control means which controls the moving-speed of the spray nozzle pipe in the prescribed area of the surface of the member to be sprayed, based on the control factor entered by the moving-speed factor entry means.  
           [0010]    In the finely-divided powder spray apparatus of the present invention, the moving-speed control factor entry means is provided to enter the moving-speed control factor for each prescribed area on the surface of the member to be sprayed and the moving-speed control means is provided to control the moving-speed of the tip of the spray nozzle pipe depending on the area of a spray point, at which the finely-divided powders are sprayed, based on the control factor entered for the prescribed area.  
           [0011]    According to the finely-divided powder spray apparatus of the present invention, the moving-speed factor is entered by the moving-speed control factor entry means for each prescribed area of the member to be sprayed. Based on the result of a test spray, for example, the moving-speed control factor for decreasing the moving-speed of the tip of the spray nozzle pipe is entered for the prescribed area having a lower density of finely-divided powders deposited, whereas a moving-speed control factor for increasing the moving-speed of the tip of the spray nozzle pipe is entered for the prescribed area having a higher density of finely-divided powders deposited. Further, the moving-speed control means controls the moving-speed of the tip of the spray nozzle pipe based on the moving-speed control factor entered by the moving-speed factor entry means, and thus the moving-speed of the tip of the spray nozzle pipe can be controlled in the prescribed area on the surface of the member to be sprayed in order to achieve a uniform density over the whole surface of the member to be sprayed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a cross-sectional view of a finely-divided powder spray apparatus of the present invention.  
         [0013]    [0013]FIG. 2 is a schematic perspective view of a finely-divided powder spray mechanism used for the finely-divided powder spray apparatus of the present invention.  
         [0014]    [0014]FIG. 3 is a cross-sectional view along the line A-A of FIG. 2 showing in detail a swing mechanism for swinging a spray nozzle pipe in the finely-divided powder spray mechanism of the present invention.  
         [0015]    [0015]FIG. 4 is a perspective view along the section B-B of FIG. 3 showing the swing mechanism of the present invention.  
         [0016]    [0016]FIG. 5 is a perspective view along the section C-C of FIG. 3 showing the swing mechanism of the present invention.  
         [0017]    [0017]FIGS. 6A, 6B,  6 C and  6 D are illustrative views showing the swing of the spray nozzle pipe by the movements of the linearly-moving actuators in the finely-divided powder spray apparatus of the present invention.  
         [0018]    [0018]FIG. 7 is an illustrative view showing the system configuration of the finely-divided powder spray system including the spacer spray apparatus of the present invention.  
         [0019]    [0019]FIG. 8 is an illustration showing the spray conditions for spraying the finely-divided powders in a trial spray using the spacer spray apparatus of the present invention.  
         [0020]    [0020]FIG. 9 is a table showing the measured densities of the deposited spacers in the individual lattice-like areas of the whole surface of the glass substrate, the spacers being sprayed by the spacer spray apparatus of the present invention in the trial spray.  
         [0021]    [0021]FIG. 10 is a graph showing the distribution of the densities of the deposited spacers on the whole surface of the glass substrate, the spacers being sprayed by the spacer spray apparatus of the present invention in the trial spray.  
         [0022]    [0022]FIG. 11 is an illustrative view showing the conditions for spraying the spacers by the spacer spray apparatus of the present invention.  
         [0023]    [0023]FIG. 12 is a table showing the densities of the deposited spacers in the individual lattice-like areas, the spacers being sprayed by the spacer spray apparatus of the present invention.  
         [0024]    [0024]FIG. 13 is a graph showing the distribution of the densities of the deposited spacers on the whole surface of the glass substrate, the spacers being sprayed by the spacer spray apparatus of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0025]    A finely-divided powder spray apparatus of the present invention will be described below in detail based on the preferable embodiments shown in the accompanying drawings.  
         [0026]    [0026]FIG. 1 is a sectional view of the finely-divided powder spray apparatus of the present invention.  
         [0027]    In the figure, a spacer spray apparatus  10  as the finely-divided powder spray apparatus of the present invention has a glass substrate  16  as a member to be sprayed, which is fixed to a table  14  disposed in a lower portion of a hermetically-sealed chamber  12 . The table  14  is grounded and thereby grounds the glass substrate  16  mounted on it so that spacers  20  as charged finely-divided powders are surely deposited on the surface of the grounded glass substrate.  
         [0028]    A spray mechanism  22  having a splay nozzle pipe  18  for spraying the spacers  20  is disposed above the table  14 . The spray nozzle pipe  18  discharges the spacers  20  transported through a flexible tube  24  together with a gas stream of air, a nitrogen gas, etc. and sprays the spacers  20  onto the glass substrate  16 . The spray nozzle pipe  18  can be swung in any of prescribed first direction and second direction perpendicular to the first direction, for example, in any of an X-axis direction and a Y-axis direction. The spray nozzle pipe  18  discharges the spacers  20  together with the gas stream while inclining in a prescribed direction, whereby the spacers  20  can be sprayed out at a prescribed position of the glass substrate  16 .  
         [0029]    [0029]FIG. 2 is a perspective view schematically showing the spray mechanism  22  for the spacers  20  in the spacer spray apparatus  10  of the present invention.  
         [0030]    In the figure, the spray mechanism  22  is arranged so that two linearly-moving actuators  28  and  30  are disposed on a mounting table  26  in parallel with each other in the Y-axis direction. Second joint units  32  and  34  composed of adjustable joints (spherical joints) are disposed on the inner sides of the linearly-moving actuators  28  and  30 , respectively. The spray nozzle pipe  18  is disposed in back of the two linearly-moving actuators  28  and  30  along the centerline therebetween so that the spray nozzle pipe  18  can be swung in any of the X-axis direction and the Y-axis direction and inclined in an arbitrary direction. The linearly-moving actuators  28  and  30  have sliders  28   a  and  30   a , and guides  28   b  and  30   b  disposed in parallel with the Y-axis direction, respectively, wherein the sliders  28   a  and  30   a  reciprocate in the Y-axis direction along the guides  28   b  and  30   b , respectively. The linearly-moving actuators used in the present invention are not particularly limited and an AC-servo-driven linear actuator, a linear stepping motor and the like can be used.  
         [0031]    A first joint unit  35  is attached to the upper end of the spray nozzle pipe  18 . In the figure, adjustable joints (universal joints)  36  and  38 , which project toward both the sides in the X-axis direction, are employed as the first joint  35 . The second joint units (adjustable joints)  32  and  34 , which are disposed on the inner sides of the linearly-moving actuators  28  and  30 , are coupled with the adjustable joints  36  and  38  of the first joint unit  35  attached to the upper end of the spray nozzle pipe  18  through two rods  40  and  42 , respectively.  
         [0032]    [0032]FIG. 3. is a sectional view along the line A-A of FIG. 2 to show in detail a swing mechanism for swinging the spray nozzle pipe  18 . FIG. 4 is a perspective view along the section B-B of FIG. 3 showing the swing mechanism. FIG. 5 is a perspective view along the section C-C of FIG. 3 showing the swing mechanism. The spray nozzle pipe  18  placed at the center in FIG. 3 is composed of a hollow pipe, has the flexible tube  24  (not shown in FIG. 3) connected to the upper end thereof, and discharges the finely-divided powders (spacers)  20  (not shown in FIG. 3) from an opening at the lower end thereof together with the gas stream. The spray nozzle pipe  18  is disposed on the mounting table  26  through a support unit (universal joint unit)  50  disposed at the center of the pipe  18  in the longitudinal direction thereof and can be swung in any of the X-axis direction and the Y-axis direction shown in FIG. 2.  
         [0033]    As shown in FIG. 3 and FIG. 4, the support unit  50  of the spray nozzle pipe  18  is equipped with a joint ring  58  in the center hole of a joint base  52  fixed to the mounting table  26 , which is supported through two support pins  54  disposed in parallel with a Y-axis and ball bearings  56  having the support pins  54  inserted, so that the joint ring  58  can rotate on the Y-axis. Further, the joint ring  58  supports the spray nozzle pipe  18  in the center hole through two support pins  60  disposed in parallel with the X-axis and the ball bearings  62  having the support pins  60  inserted, so that the joint ring  58  can rotate on the X-axis. Accordingly, the spray nozzle pipe  18  can be swung in any of the X-axis direction and the Y-axis direction and cannot be rotated on the centerline thereof.  
         [0034]    The adjustable joints  36  and  38  of the first joint unit  35  are attached to the upper end of the spray nozzle pipe  18  and couple the pipe  18  with the second joint units  32  and  34  disposed on the inner sides of the linear-moving actuator  28  and  30  shown in FIG. 2 through the rods  40  and  42 . As shown in FIG. 3 and FIG. 5, the adjustable joints (universal joints)  36  and  38  are attached to the upper end of the spray nozzle pipe  18  so as to project toward both the sides of the upper end in the X-axis direction. They are composed of two rotary rings  68  mounted on the upper end of the spray nozzle pipe  18  through ball bearings  66  which rotate in a horizontal direction and a joint arm  72  connected to the rotary rings  68  through ball bearings  70 .  
         [0035]    When it is not necessary to so much increase the inclining angle of the spray nozzle pipe  18 , spherical joints using spherical bearings may be employed in place of the adjustable joints  36  and  38  of the first joint unit  35  as the universal joints.  
         [0036]    The rod  40  ( 42 ) is fixed to the joint arm  72  and coupled with the second joint unit  32  ( 34 ) of the linearly-moving actuator  28  ( 30 ) through the rod  40  ( 42 ), so that the movement of the linearly-moving actuator  28  ( 30 ) is transmitted to the spray nozzle pipe  18 . The adjustable joints of the second joint units  32  and  34  of the linearly-moving actuators  28  and  30  may be the same as the adjustable joints  36  and  38 , or any adjustable joints such as spherical joints may be employed.  
         [0037]    The joint base  52  is fixed to the mounting table  26  through a mounting ring  74 . The mounting ring  74  has an adjusting mechanism  76  for adjusting the position of the spray nozzle pipe  18 . The lower end of the spray nozzle pipe  18  is inserted into a rubber cover  78  for hermetically sealing the chamber  12  as well as permitting the spray nozzle pipe  18  to swing. The outer periphery of the rubber cover  78  is fixed to the mounting table  26  through a fixing ring  80 . When the spray mechanism  22  is driven, there is a possibility that dust and dirt are generated from the support unit  50  of the spray nozzle pipe  18  and the like although their amount may be negligible. The rubber cover  78  is attached to prevent the invasion of the dust and dirt other than the spacers into the chamber  12 .  
         [0038]    In the spray mechanism  22  arranged as described above for spraying the spacers  20 , the spray nozzle pipe  18  is swung as described below by the movement of the linearly-moving actuator  28  ( 30 ), more specifically, by the movement of the slider  28   a  ( 30   a ) thereof along the guide  28   b  ( 30   b ).  
         [0039]    [0039]FIGS. 6A to  6 D are illustrative views showing the swing of the spray nozzle pipe  18  by the movements of the slider  28   a  ( 30   a ) of the linearly-moving actuator  28  ( 30 ), respectively. FIG. 6A shows the spray nozzle pipe  18  being located at the center (vertical position) of a moving area. FIG. 6B shows the positions of the linearly-moving actuators  28  and  30 , more specifically, the positions of the sliders  28   a  and  30   a  of the linearly-moving actuators  28  and  30  when the spray nozzle pipe  18  is swung to the limit position of the moving area in the Y-axis direction. FIG. 6C shows the positions of the linearly-moving actuators  28  and  30  (sliders  28   a  and  30   a ) when the spray nozzle pipe  18  is swung to the limit position of the moving area in the X-axis direction. FIG. 6D shows the spray nozzle pipe  18  being located in the corner of the moving area.  
         [0040]    As illustrated in FIGS. 6A, 6B and  6 C, when the spray nozzle pipe  18  is swung in the Y-axis direction, two linearly-moving actuators  28  and  30  simultaneously move in the same direction, and when the spray nozzle pipe  18  is swung in the X-axis direction, the two linearly-moving actuators  28  and  30  simultaneously move in the opposite direction each other. When the spray nozzle pipe  18  is swung at any other angle, it can be moved at any rate in the X-axis direction and the Y-axis direction by synthesizing the moving direction and speed of the two linearly-moving actuators  28  and  30 , whereby the spacers  20  can be sprayed out to any position of the glass substrate  16 .  
         [0041]    [0041]FIG. 7 is a schematic view showing a system configuration of a finely-divided powder spray system  90  including a spacer spray apparatus  10 . The finely-divided powder spray system  90  is composed of the spray apparatus  10 , an actuator driver  92  electrically connected to the spray apparatus  10 , more specifically, to the linearly-moving actuators  28  and  30  of the spray mechanism  22  for controlling them, a sequencer  94  electrically connected to the driver  92 , and a touch panel  96  electrically connected to the sequencer  94  for operating the spray apparatus  10 , especially entering the control factor to swing the sequencer  94 .  
         [0042]    It is described below how the spacers  20  are sprayed onto the glass substrate  16 . Before the spacers  20  are sprayed onto the glass substrate  16 , the spacers  20  must be sprayed onto a sample glass substrate  16  by way of trial. In this case, data such as a locus along which the spray nozzle pipe  18  moves, a size of the glass substrate  16  (width×height: for example, 720 cm×600 cm) and a condition for spraying the spacers  20  is entered by the touch panel  96 .  
         [0043]    [0043]FIG. 8 is an illustration showing the conditions for spraying the sample spacers  20  in a trial spray. As shown in the figure, the surface of the glass substrate  16  to be sprayed are divided into a matrix of 12×10 (row×column) lattice-like areas, and a control factor C is entered for each lattice-like area to make the conditions in a trial spray. The control factor “5”, indicates that no correction is made to the spray condition. Any of the control factors “6”-“9” indicates that the correction is made so as to increase a spray density (so as to decrease the moving-speed of the tip of the spray nozzle pipe) as a larger factor is specified. Any of the control factors “1”-“4” indicates that the correction is made so as to decrease the spray density (so as to increase the moving-speed of the tip of the spray nozzle pipe) as a smaller factor is specified. Since no correction is made in the trial spray, the control factor “5” is entered for all the 12×10 (row×column) lattice-like areas.  
         [0044]    The entered data such as the locus along which the spray nozzle pipe  18  moves, the size of the glass substrate  16 , and the condition for spraying the spacers  20  is transferred through the sequencer  94  to the actuator driver  92 , which in turn determines the locus to be drawn by an extension from the tip of the spray nozzle pipe in the X-Y coordinate system on the glass substrate  16 . An origin of the X-Y coordinate system, in which corresponding locations on the glass substrate  16  are represented, is assumed to be an intersection of the perpendicularly-directed extension from the tip of the spray nozzle pipe  18  and the glass substrate  16 . The locus drawn by the extension from the tip of the spray nozzle pipe  18  on the glass substrate  16  can be determined as a continuity of plural control points ((x 1 , y 1 ), (x 2 , y 2) , (x 3 , y 3 ), (x 4 , y 4 ), . . . (x n , y n )).  
         [0045]    The actuator driver  92  calculates an incline angle of the spray nozzle pipe  18  in the X-Y direction from the locus drawn in the X-Y coordinate system on the glass substrate  16 , and converts the control points in the X-Y coordinate system into the corresponding positions of the sliders  28   a  and  30   a  of the linearly-moving actuators  28  and  30  in the L 1 -L 2  coordinate system ((L 1   1 , L 2   1 ), (L 1   2 , L 2   2 ), (L 1   3 , L 2   3 ), (L 1   4 , L 2   4 ), . . . (L 1 , L 2   n )). In the L 1 -L 2  coordinate system, sliding positions of the sliders  28   a  and  30   a  of the linearly-moving actuators  28  and  30  are represented.  
         [0046]    Next, the actuator driver  92  operates the spacer spray apparatus  10 , and changes the incline angle of the spray nozzle pipe  18  so as to shift the spray position along the determined locus at a temporary speed (V) while sequentially moving the sliders  28   a  and  30   a  of the linearly-moving actuators  28  and  30  to the positions ((L 1   1 , L 2   1 ), (L 1   2 , L 2   2 ), (L 1   3 , L 2   3 ), (L 1   4 , L 2   4 ), . . . (L 1   n , L 2   n )), whereby the spacers  20  are sprayed onto the sample glass substrate  16  in the trial spray.  
         [0047]    After the trial spray, densities of the spacers  20  deposited on the sample glass substrate  16  are measured by a spacer counter (not shown in the figure). FIG. 9 is a table showing measured values (spacers/mm 2 ) of densities of the deposited spacers  20  in all the 12×10 (row×column) lattice-like areas, the spacers being sprayed on the whole surface of the substrate  16  having a size of 20 cm×600 cm, (the densities are measured at the centers of the lattice-like areas). FIG. 10 is a graph showing a distribution of the densities of the deposited spacers (spacers/mm 2 ) on the whole glass substrate  16  based on the measured values shown in FIG. 9.  
         [0048]    The conditions for spraying the spacers  20  are then entered by the touch panel  96  with reference to the graph of FIG. 10 showing the distribution of the spacers deposited on the whole surface of the glass substrate  16 .  
         [0049]    As seen in this graph of the distribution of the densities, the densities are low in the right and left parts of the glass substrate  16  whereas the densities are high in the upper and lower parts thereof, and therefore, the values of the spray conditions are entered as shown in FIG. 11. In other words, since the densities of the deposited spacers are low in the right and left parts of the glass substrate  16 , the control factor “8” (indicating that the correction is made so as to increase the density (so as to decrease the moving-speed of the tip of the spray nozzle pipe)) is entered, and since the densities of the deposited spacers are high in the upper and lower parts of the glass substrate  16 , the control factor “4” (indicating that the correction is made so as to decrease the density (so as to increase the moving-speed of the tip of the spray nozzle pipe)) is entered.  
         [0050]    Subsequently, the actuator driver  92  calculates the moving-speed of a spray point, at which the extension of the spray nozzle pipe  18  intersects with the glass substrate  16  between control points in the X-Y coordinate system. The moving-speed of the spray point between the control points (x 1 , y 1 ) and (x 2 , y 2 ) is determined depending on where the control point (x 1 , y 1 ) is located among the 12×10 lattice-like areas of the glass substrate  16 . In other words, the moving-speed of the spray point between the control points (x 1 , y 1 ) and (x 2 , y 2 ) is calculated by multiplying the moving-speed (temporary speed V) of the spray point in the trial spray by the control factor entered for the area of the control point (x 1 , y 1 ). In the case that the control factor entered for the area of the control point (x 1 , y 1 ) is C 1  (any of “1”-“9”), the moving-speed can be calculated by the expression (C 1 ×V).  
         [0051]    In the same manner, the moving-speed of the spray point between the control points (x 2 , y 2 ) and (x 3 , y 3 ) is determined depending on where the control point (x 2 , y 2 ) is located among the 12×10 lattice-like areas of the glass substrate  16 . If the control factor entered for the area of the control point (x 2 , y 2 ) is C 2  (any of “1”-“9”), the moving-speed of the spray point between (x 2 , y 2 ) and (x 3 , y 3 ) can be calculated by the expression (C 2 ×V). Further, the moving-speed (C 3 ×V) of the spray point between (x 3 , y 3 ) and (x 4 , y 4 ), and the moving-speed (C n−1 ×V) of the spray point between (x n−1 , y n−1 ) and (x n , y n ) can also be calculated in the same manner.  
         [0052]    The actuator driver  92  further calculates the moving-speeds of the sliders  28   a  and  30   a  of the linearly-moving actuator  28  and  30  based on a distance between the control points and the moving-speed of the spray point in the X-Y coordinate system. More specifically, the actuator driver  92  calculates the moving-speeds of the sliders  28   a  and  30   a  of the linearly-moving actuator  28  and  30  between (L 1   1 , L 2   1 ) and (L 1   2 , L 2   2 ), based on a distance between the control points (x 1 , y 1 ) and (x 2 , y 2 ) and the moving-speed (C 1 ×V) of the spray point between the control points (x 1 , y 1 ) and (x 2 , y 2 ). In the same manner, the actuator driver  92  calculates the moving-speeds of the sliders  28   a  and  30   a  of the linearly-moving actuator  28  between (L 1   2 , L 2   2 ) and (L 1   3 , L 2   3 ), between (L 1   3 , L 2   3 ) and (L 1   4 , L 2   4 ), and between (L 1   n−1 , L 2   n−1 ) and (L 1   n , L 2   n ), respectively.  
         [0053]    Next, the glass substrate  16 , onto which the finely-divided powders is actually sprayed, is positioned and fixed on the table  14  installed in the hermetically-sealed chamber  12 . The glass substrate  16  must be fixed at the same position as the sample glass substrate used in the trial spray of the spacers  20 .  
         [0054]    Next, the actuator driver  92  operates the spacer spray apparatus  10  to spray the spacers  20  on the glass substrate  16  while sequentially moving the sliders  28   a  and  30   a  of the linearly-moving actuators  28  and  30  to the points (L 1   1 , L 2   1 ), (L 1   2 , L 2   2 ), (L 1   3 , L 2   3 ), (L 1   4 , L 2   4 ), . . . (L 1   n , L 2   n ) at the calculated speed. Accordingly, the spacers  20  can be sprayed onto the glass substrate  16  while shifting the spray point between the control points (x 1 , y 1 ) and (x 2 , y 2 ) at the moving-speed of (C 1 ×V), the spray point between the control points (x 2 , y 2 ) and (x 3 , y 3 ) at the moving-speed of (C 2 ×V), the spray point between the control points (x 3 , y 3 ) and (x 4 , y 4 ) at the moving-speed of (C 3 ×V), and the spray point between the control points (x n−1 , y n−1 ) and (X n , y n ) at the moving-speed of (C n−1 ×V), respectively.  
         [0055]    [0055]FIG. 12 is a table showing the measured densities of the spacers (spacers/mm 2 ) deposited in the individual 12×10 (row×column) lattice-like areas on the whole surface of the glass substrate  16  when spraying the spacers  20  on the glass substrate  16  in accordance with the entered spray conditions (the densities of the spacers  20  were measured at the centers of the lattice-like areas). FIG. 13 is a graph showing a distribution of the densities of the deposited spacers  20  on the whole surface of the glass substrate  16  based on the measured densities of the deposited spacers  20  shown in FIG. 12. As apparent from the measured values shown in FIG. 13, the moving-speed of the tip of the spray nozzle pipe  18  is locally controlled, the spacers  20  can be uniformly sprayed on the whole surface of the glass substrate  16 . After one glass substrate  16  has been sprayed with the spacers  20 , another glass substrate  16  will be sprayed with the spacers  20  subsequently in the same manner.  
         [0056]    According to the spacer spray apparatus  10  of the present invention, the control factors are entered individually for the prescribed areas. For example, depending on the measurement results, the control factor is entered for decreasing the moving-speed of the tip of the spray nozzle pipe  18  in the prescribed area in which the density of the deposited spacers is low, whereas the control factor is entered for increasing the moving-speed of the tip of the pipe  18  in the other prescribed area in which the density of the deposited spacers is high, whereby the spray densities of the spacers  20  deposited on the whole surface of the glass substrate  16  can be uniform.  
         [0057]    In the aforementioned embodiment, the spacer spray apparatus  10  sprays the spacers  20  onto the glass substrate  16  positioned and horizontally fixed on the table  14  by swinging the spray nozzle pipe  18  disposed above the glass substrate so that the spacers  20  are uniformly sprayed downward. However, the present invention is by no means limited to the aforementioned embodiment. Any types of finely-divided powders which should be a uniformly sprayed can be used, for example, powder paints, toner, etc. in addition to the spacers. Any members to be sprayed can also be used, for example, objects to be coated by powder paints in addition to the glass substrate. They are not limited to those horizontally fixed on the table  14 , and can be, for example, those not mounted on the table, vertically-disposed substrates and parts to be painted, and inclined substrates and parts to be painted. The direction in which the spacers are sprayed onto the member to be sprayed is also not limited to the aforementioned embodiment and the spacers may be sprayed onto the horizontally-disposed or inclined member in any of the perpendicularly-downward and oblique directions as well as onto the vertically-disposed or inclined member in any of the horizontal and oblique directions.  
         [0058]    In the aforementioned embodiment, the spray nozzle pipe  18  is swung in the X-axis direction and the Y-axis direction by controlling the sliders  28   a  and  30   a  of the linearly-moving actuators  28  and  30 . However, the present invention may be applied to a spacer display apparatus of which spray nozzle pipe  18  is swung in the X-axis direction and the Y-axis direction through a crank or an eccentric cam linked to the motor.  
         [0059]    Further in the aforementioned embodiment, the surface of the glass substrate  16  to be sprayed is divided into 12×10 lattice-like areas, for which the control factors are individually entered to control the moving-speed of the tip of the spray nozzle pipe  18 . However, the number of the divided areas may be varied, if necessary.  
         [0060]    According to the present invention, the control factors may be entered by the control factor entry means individually for the prescribed areas of the member to be sprayed, and thus the density of the deposited finely-divided powders may be partially changed easily by the touch panel and the like.