COATING METHOD, COATING SYSTEM, METHOD OF MANUFACTURING COLOR FILTER SUBSTRATE EMPLOYING THE COATING METHOD, AND LIQUID CRYSTAL DISPLAY DEVICE EMPLOYING THE COLOR FILTER SUBSTRATE MANUFACTURED IN ACCORDANCE WITH THE COATING METHOD

Abstract

A disclosure is directed to a coating method of a liquid on the surface of a member during a coating head and the member are moved relatively, thereby forming a coating film. An improvement resides in that a process of mixing plural kinds of coating liquid with one another, and a process of supplying the resultant mixed liquid to the coating head are substantially, simultaneously carried out. The method is used, for example, in producing a color filter of a liquid crystal display device.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates in general to a method and a system for coating a coating liquid to the surface of a member to which the coating liquid is to be applied by moving relatively a coating head and the member. In particular, such a method and a system are suitably used when manufacturing a color filter for use in a color television, a personal computer, and the like.

[0003] 2. Related Background Art

[0004] Heretofore, as for the method of manufacturing the color filters, there are well known the coloring method, the pigment dispersion method, the electrocoating method, the printing method and the like. In each of these methods, however, in order to color the three primary colors R, G and B, the same process needs to be repeatedly carried out three times. For this reason, since the number of processes is large, the yield is reduced and the cost is increased.

[0005] In addition, in the case of the electrocoating method, the shape of the formable pattern is limited, and hence it is difficult to apply this method to the manufacture of the TFTs. In addition, in the case of the printing method, the resolution becomes poor and hence it is difficult to cope with the scale down (shrink) of the patterns.

[0006] Then, in order to make up the above-mentioned disadvantages, there has been proposed the technology in which the ink jet is jetted onto a glass substrate to form the pattern of the filter (refer to Japanese Patent Application Laid-Open No. 59-75205 and the like). In this technology, since the pixels of three primary colors R, G and B are simultaneously formed, it is possible to greatly shorten the process. However, in this technology, since the primary colors R, G and B are painted in the state of the droplets, the phenomenon occurs which is called the color mixing in which the primary colors are mixed with one another.

[0007] In order to prevent such color mixing, in Japanese Patent Application Laid-Open No. 8-75916, there is proposed the technology in which the layer (the ink acceptable layer) made of resin or resinous composition which has the ink acceptability and which is cured or decreased with the remaining amount of hydrophilic groups thereof by the application of the light, the heat or the like thereto is formed on the substrate and at least a part of the non-pixel area defined between the pixels is cured or the remaining amount of hydrophilic groups is decreased to provide the ink repellency to form the color mixing preventing layer (the ink repellency layer), whereby the color lack in the pixels, the spreading of the ink to the adjacent pixels and the color mixing are prevented.

[0008] Also, in the process of manufacturing the color filter, in addition to the above-mentioned ink acceptable layer, the protection layer (the over coat layer) for protecting the colored surface, which is made of resin, is also formed. In addition, a photosensitive material which is used to etch a black matrix for the higher contrast promotion or the higher colorfulness when carrying out the display using the color filter is also made of resin and also the black matrix itself may be formed of resin (the resin matrix) in some cases.

[0009] Now, as for the coating liquid which is used to form such a resin layer or a resin film, normally, the liquid is employed which is obtained in such a way as to mix the two or more liquid components with one another at a fixed ratio. Heretofore, such a mixed liquid is previously, relatively produced on a massive scale for half a day or a day for example and is stored in a coating material tank 41 as shown in FIG. 4 in order to be supplied from the tank 41 to a member 7 to which the coating liquid is to be applied. In FIG. 4, reference numeral 5 designates a nozzle; reference numeral 6 designates a coating film; reference numeral 7 designates a member to which the coating liquid is to be subjected to a coating; reference numeral 8 designates a carrier stage; reference numeral 41 designates a coating material tank; reference numeral 42 designates a pipeline; reference numeral 43, a quantity measuring pump; reference numeral 44, a shut-off valve; reference numeral 45, a filter; and 54, a slit.

[0010] In this connection, there arises a problem in that the viscosity of the mixed liquid as described above changes with a lapse of time, and hence it is difficult to control the thickness of the coating liquid; the gel and the like is generated in the coating liquid supplying route to generate the coating defects and as a result the cleaning is forced to be carried out therefor at the high frequency; the frequency of the mixing and the frequency of filling the coating material tank 41 with the coating material are both increased due to the limitation of the pot life (the time interval for use); the mixed liquid is wasted on; and so forth.

SUMMARY OF THE INVENTION

[0011] In the light of the foregoing, the present invention was made in order to solve the above-mentioned problems associated with the prior art, and it is therefore an object of the present invention to promote the labor saving and the high reliability in coating with the coating liquid which has been obtained by mixing a plurality of different liquid with one another.

[0012] In order to solve the above-mentioned problems associated with the prior art, according to one aspect of the present invention, there is provided a coating method in which the coating liquid is discharged on the surface of a member to which the coating liquid is to be applied by moving relatively a coating head and the member to form a coating film, characterized in that the process of mixing plural kinds of coating liquid with one another, and the process of supplying the resultant mixed liquid to the coating head are substantially, simultaneously carried out.

[0013] In addition, according to another aspect of the present invention, there is provided an application system having: a coating liquid supplying apparatus for supplying the coating liquid to a coating head having a slit for discharging therethrough the coating liquid; a stage for holding a member to be coated with the coating liquid; and driving means for moving relatively the stage and the coating head, characterized in that the coating liquid supplying apparatus includes: mixing means for mixing equal to or more than two different coating liquid with one another at a fixed ratio; and mixed liquid supplying means for supplying the resultant mixed liquid to the coating head.

[0014] Further, according to still another aspect of the present invention, there is provided a coating system for applying a two liquid mixed type application liquid to the surface of a member to be coated with the coating liquid to form a coating film, characterized in that a coating liquid supplying apparatus includes: first quantity measuring supply means for supplying a first coating liquid from a first tank to mixing means at a first flow rate; second quantity measuring supply means for supplying a second coating liquid from a second tank to the mixing means at a second flow rate; and mixed liquid supplying means for supplying the mixed liquid which has been obtained in the mixing means to a coating head at a third flow rate.

[0015] According to the present invention, in coating with the coating liquid which has been obtained by mixing a plurality of different liquid with one another, the process of mixing the liquid can be carried out right before the coating, and hence the coating becomes possible without any of the limitations for the pot life of the coating liquid. In addition, it is possible to prevent the gel and the like from being generated in the coating liquid supplying route and also it is possible to prevent any of the coating defects resulting therefrom from being generated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a schematic view showing the construction of one example of a coating system according to the present invention;

[0017] FIGS. 2A, 2B, 2C, 2D and 2E are respectively schematic process views showing one example of a method of manufacturing a color filter substrate according to the present invention;

[0018] FIG. 3 is a cross sectional view showing one example of a liquid crystal display device according to the present invention; and

[0019] FIG. 4 is a schematic view showing the construction of a conventional coating system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The preferred embodiments of the present invention will hereinafter be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic view showing the construction of one example of a coating system in which a single substrate automatically coating method according to the present invention is implemented. In the figure, the coating materials of the two liquid mixed type are supplied from a coating material tank 11 and a coating material tank 21 by a quantity measuring pump 14 and a quantity measuring pump 24, respectively. By each of the quantity measuring pumps 14 and 24 of this sort is meant a capacity pump such as a gear pump, diaphragm pump or a syringe pump. In addition, as for the mechanism for supplying the coating material other than the pump, there is also possible the form wherein the coating material tank is accommodated in a pressure vessel, and the pressurized air is supplied to the pressure vessel by the pressure pump to press out the coating material. In this connection, the ratio of the flow rate of the liquid which is supplied from the quantity measuring pump 14 to the flow rate of the liquid which is supplied from the quantity measuring pump 24 is held constant.

[0021] The coating materials which have been respectively supplied by the quantity measuring pumps 14 and 24 are uniformly mixed with each other in a stirring unit 3. The stirring unit 3 is meant the static mixer having the helical passage, the dynamic mixer of the type in which the stirring is carried out by rotating the gear, the fun or the like. In addition, filters 13 and 23 are respectively provided in the passages of the pipelines 12 and 22 which extend from the coating material tanks 11 and 21 to the quantity measuring pumps 14 and 24, respectively. Further, the shut-off valve may be provided therein if necessary.

[0022] The liquid which has been obtained by the uniform mixing is temporarily stored in a reservoir tank 25 through the stirring unit 3. Then, the liquid is supplied to the nozzle 5 by a quantity measuring pump 43. But, in addition thereto, there are also possible the form wherein the mixed coating material is directly supplied to the quantity measuring pump 43 without through the reservoir tank 25, or the form wherein the mixed coating material is directly supplied from the stirring unit 3 to the nozzle 5. In this connection, even in the case where the mixed coating material is supplied without through the reservoir tank 25, when stopping the supply of the mixed coating material at the end portion of the member to which the coating liquid is to be applied, and so forth, it is preferable that the above-mentioned reservoir tank 25 is connected as a buffer tank in which the mixed coating material flowing out from the stirring unit 3 is temporarily stored to the passage. In addition, while for the reservoir tank 25, the coating material tank 41 which is employed in order to store therein the mixed liquid in the conventional application system shown in FIGS. 2A to 2E may be directly employed, even the tank of the smaller capacity is also enough.

[0023] If necessary, a shut-off valve 44 is provided in the passage of a pipeline 42 extending from the reservoir tank 25 to the nozzle 5.

[0024] The nozzle 5 having a front lip 51 and a rear rip 52 is provided with a coating material supply port and a manifold 53 for uniforming the pressure distribution of the coating material while the coating material flows from the coating material supply port to a coating material slit 54. In this connection, the slit gap (the gap defined between the front lip 51 and the rear lip 52) of the slit 54 is preferably in the range of 10 to 200 &mgr;m.

[0025] The nozzle 5 is installed in such a way as to face the member 7, to be coated with the coating liquid, through a fixed gap (the clearance). The size of the clearance is preferably in the range of 20 to 500 &mgr;m.

[0026] The member 7 to be coated with coating liquid is placed on a flat carrier stage 8 and is vacuum-sucked on the carrier stage 8 in order to be prevented from slipping out of place during the coating process.

[0027] The coating material is started to be supplied to the nozzle 5 by the quantity measuring pump 43 and without delay or after a lapse of predetermined time, the nozzle 5 or the carrier stage 8 is moved in parallel. Right before the nozzle 5 or the carrier stage 8 has reached the end portion of the member to be coated with the coating liquid, the supply of the coating material from the quantity measuring pump 43 is stopped and the movement of the nozzle 5 or the carrier stage 8 is also stopped. In such a way, the coating of the thin film having the uniform thickness distribution is carried out.

[0028] The coating method the present invention is suitably applied to a process of manufacturing a color filter which is the constituent member of the liquid crystal display device of the color display type. In general, in the color filter, a light shielding layer which is made of black metal or black resin called the black matrix or the black stripe, a coloring layer in which each of the opening portions of the light shielding layer is utilized as the colored pixel and which has the colored pixels of three primary colors R (red), G (green) and B (blue), and a protection layer which may be provided if necessary are formed in this order on a transparent substrate. Therefore, the coating system according to the present invention is applied to the coating and the formation of the light shielding layer, the coloring layer and the protection layer or the application of resist which is used in the patterning of those coating films, whereby it is possible to form the coating film which is wide in the effective area and which is uniform in the thickness, and also the excellent color filter can be formed with high yield.

[0029] For example, the color filter can be manufactured on the basis of a series of processes as shown in FIGS. 2A to 2E. In this connection, FIGS. 2A to 2E correspond to the following processes (a) to (e), respectively.

[0030] (a) A black photosensitive resinous composition 2 is applied onto a transparent substrate 1 in accordance with the coating method of the present invention. The thickness of the film which has been obtained by the coating is enough to obtain the necessary light shielding property and is, for example, about 1 &mgr;m. In this connection, while for the transparent substrate, for example, glass is employed in many cases, alternatively, the plastic film or the plastic sheet may also be employed therefor. In addition, for the purpose of improving the adhesion between the transparent substrate, and the black matrix and the coloring ink, if necessary, a thin film for improving the adhesion may also be previously formed on the transparent substrate.

[0031] (b) The resultant layer which has been obtained by the application is temporarily cured using the hot plate for example and is then exposed using exposure apparatus which has the wavelength matching with the sensitivity of the photosensitive resinous composition and a mask 3 having a predetermined pattern formed thereon.

[0032] (c) By carrying out the development, if the photosensitive resinous composition 2 is of the negative type, then the portion which was shielded from light by the mask 3 during the exposure is eluded by a liquid developer to expose the corresponding surface portion of the substrate so that the exposed portion remains in the form of the black matrix pattern. Subsequently, the liquid developer adhered to the coating layer is washed away using the rinse and then the coating layer is simply dried by utilizing the spin drying, the air knife or the like. As a result, the surface of the substrate having the gap portions 4 of the black matrix formed thereon becomes the clear surface.

[0033] (d) An ink 30 having a predetermined color is applied to each of a gap areas 4 of the black matrix. As for the method of applying the ink, while the general printing method or the like such as the offset printing, the gravure printing or the screen printing may be employed, in particular, an ink jet printing method using an ink jet printing machine is preferable in the respect that since any of the plates is not used during the printing, if the diameter of the in droplet is controlled, then the patterning can be carried out with high accuracy. As for the ink which is used in this process, such an ink is suitably selected to be used that is easy to be shed on the above-mentioned black matrix pattern, but is easy to be wet in each of the pixel areas in the gap of the black matrix. In general, the surface energy (the surface tension) is in the range of 30 to 70 dyne/cm. Such an ink may be either the dry series or the pigment series, and also may contain the hydrophilic organic solvent or the like with water as the main component.

[0034] Employing the thermosetting ink as the ink is preferable in the respect that the curing of the ink and the main curing of the black matrix can be carried out in the same process.

[0035] As for the thermosetting component which is contained in the ink, such a material is preferable that is cured under substantially the same temperature conditions as those of the main curing of the black matrix, and hence is suitably selected from the group consisting of acrylic resin, epoxy resins, phenolic resins, entiore and the like. In addition, the ink may also be employed in which in accordance with the required process temperature, aromatic amine, acid anhydride or the like is introduced into resin as described above.

[0036] (e) The heat drying treatment (the post-baking) is executed in order to main-cure the black matrix to form the black matrix. At this time, the main curing of the ink is also preferably carried out. Thereafter, if necessary, the protection film is formed using the coating system of the present invention.

[0037] FIG. 3 is a cross sectional view showing the structure of a TFT color liquid crystal panel in which the color filter is incorporated which is manufactured in accordance with the coating method of the present invention. In this connection, it is to be understood that the form thereof is not limited to the present example.

[0038] In general, the color liquid crystal panel is formed so that the color filter substrate 1 and a counter substrate 64 are arranged in such a way as to face each other and then the space defined between the substrates 1 and 64 is filled with a liquid crystal composition 62. The TFTs (not shown) and transparent pixel electrodes 63 are both formed in a matrix on the inner portion of one substrate 64 of the liquid crystal panel. On the other hand, a color filter substrate 69 is arranged in the inner portion of the other substrate 1 in such a way that the color materials of R, G and B are arranged in the positions opposite to the pixel electrode, and a transparent opposing electrode (a common electrode) 60 is formed on the whole surface thereof. In general, the black matrix is formed on the side of the color filter substrate. In addition, orientation films 61 are formed on the surfaces of both of the substrates facing each other, and they are subjected to the rubbing process, thereby enabling the liquid crystal molecules to be oriented in a fixed direction. In addition, polarizing plates 65 are adhered to the outer surfaces of the glass substrates, respectively, and as described above, a gap (in the range of about 2 to about 5 &mgr;m) defined between those glass substrates is filled with the liquid crystal compound 62. In addition, as for a back light, in general, the combination of a fluorescent lamp (not shown) and a scattering plate (not shown) is employed. Then, the liquid crystal compound is made act as an optical shutter for changing the transmissivety of the back light, thereby carrying out the display. In the figure, reference numeral 36 designates a protection layer which is formed if necessary.

[0039] [Embodiments]

[0040] The preferred embodiments of the present invention and the comparative examples therewith will hereinafter be described in detail.

[0041] (Embodiment 1)

[0042] SS-6699G (the main agent) as two liquid curing type resin and SS-0699G as its curing agent (both of them are manufactured by JSR) are adopted as the coating material, and the substrate on which three-layer low reflective chromium film is formed on the whole surface of a no-alkali glass substrate 1733 (manufactured by Corning Co., Ltd.) of 360 mm×465 mm×0.7 mm is employed as the member to which the application liquid is to be applied, and also the coating is carried out using the coating system having the construction as shown in FIG. 1.

[0043] As each of the quantity measuring pumps 14, 24 and 43, the high accuracy diaphragm pump is employed. The dynamic mixer employing the gear is employed as the stirring unit 3. Also, for the driving of the substrate carrier stage 8, the high accuracy servo motor is adopted.

[0044] The above-mentioned SS-6699G and SS-0699G are stored in the coating material tank 11 and the coating material tank 21, respectively, and the liquid feeding passage extending up to the nozzle 5 is previously filled with the mixed coating material.

[0045] The flow rate of the quantity measuring pump 14 and the flow rate of the quantity measuring pump 24 are respectively set to 61.4 &mgr;l/sec and 12.7 &mgr;l/sec, and the volume ratio of the main agent to the curing agent is maintained at 29:6.

[0046] In addition, the capacity of the reservoir tank is set to 50 ml and the liquid surface sensors (not shown) are provided in the position near the level of 20 ml and the position of the level of 50 ml, respectively. Then, when the amount of mixed coating material in the reservoir tank has been decreased down to the level of up to 20 ml, the supply of the coating materials by the quantity measuring pumps 14 and 24 is restarted, and the amount of mixed coating material in the reservoir tank has reached the level of up to 50 ml, the supply of the mixed coating materials thereby is stopped.

[0047] The slit gap is set to 30 &mgr;m and the distance (the clearance) between the tip of the nozzle and the surface of the member to be coated with the coating liquid is set to 50 &mgr;m. In addition, for the purpose of preventing the mixed coating material from being spread up to the side face and the rear face of the member 7 to which the application liquid is to be applied, the crossing width of the discharge opening of the slit tip is set to 356 mm.

[0048] The discharge rate is set in such a way that the substrate carrying speed is 52 mm/sec and the flow rate of the quantity measuring pump 43 is 74.1 &mgr;l/sec, and the coating is carried out in such a way that the point of starting the coating and the point of completing the coating fall within the inside from the end portion of the substrate by 1.0 mm. After the resultant substrate to which the coating liquid was applied has been dried for 20 min. in the oven the temperature of which is held at 90° C., the baking is carried out for 60 min. in the oven at the temperature of 230° C. to obtain the coating film 6.

[0049] Both of the coating material tanks 11 and 21 are filled with the new coating material, and the coating is continuously carried out at intervals of 1 min. in accordance with the above-mentioned coating method. Then, for 24 hours right after having supplied the new liquid, the substrate to which the coating liquid has been applied is pulled out every lapse of 4 hours, and then the number of particles lying on the substrate is measured using the particle counter GI-4700 manufactured by Hitachi Electronics Engineering Co., Ltd. In this connection, for each of those substrates thus pulled out, the number of particles lying thereon is previously measured on the basis of the same measuring method before having charged the coating system. Then, the number of particles which are considered to be generated in the coating process is measured on the basis of the difference between the two particle measurement results. In this connection, the object of the particle to be measured is in the range of equal to or larger than 1 &mgr;m to smaller than 5 &mgr;m in diameter. These measurement results are shown in Table 1.

[0050] (Embodiment 2)

[0051] A no-alkali glass substrate 1737 (manufactured by Corning Co., Ltd.) of 360 mm×465 mm×0.7 mm is employed as the member to be coated with the coating liquid, and SS-6699G (the main agent) as two liquid curing type resin and SS-0699G as its curing agent (both of them are manufactured by JSR) are adopted as the coating material similarly to Embodiment 1, and hereinafter, the coating film 6 is obtained by utilizing the same coating method as that in Embodiment 1.

[0052] For 24 hours right after having supplied the new liquid, the substrate coated with the coating liquid is pulled out every lapse of 4 hours, and then the thickness of the coating film is measured at nine points within the substrate using the tracer method type film thickness measuring apparatus FP-20 manufactured by Tencall Co., Ltd. The measurement results are shown in Table 2 with the mean value of the film thickness at nine points as the central value.

[0053] (Embodiment 3)

[0054] A photosensitive resinous composition made of acrylate series polymer as will hereinbelow be shown is applied to the glass substrate having the black matrix formed thereon to form a resin layer.

[0055] More specifically, after the coating with the photosensitive resinous composition using the spin coater, the pre-bake processing is carried out for 20 min. at 90° C. to form the photosensitive resin layer with 1 &mgr;m film thickness. 1 Photosensitive resinous composition Methyl methacrylate 5.0 parts by weight Hydroxy methyl methacrylate 3.0 parts by weight Ternary copolymer made of 2.0 parts by weight N-methylol acrylamide Triphenyl sulfonium 0.3 parts by weight trifluorate (TPS-105 manufactured by Midori Chemistry Co. Ltd.) Ethyl cellosolve 89.7 parts by weight

[0056] Next, a part of the resin layer formed on the black matrix is exposed with the exposure of 1 J/cm2 through the photo mask having the opening portion which is narrower than the width of the black matrix to form the predetermined pattern. In addition, the un-exposed portion of the resin layer is colored R, G and B with the dye inks having the following composition using the ink jet recording apparatus to form the matrix pattern of R, G and B. 2 Ink composition Dye 5 parts by weight Ethylene glycol 10 parts by weight Isopropyl alcohol 3 parts by weight Ion exchange water 82 parts by weight Dye R: C.I. Acid Red 118 G: C.I. Acid Green 25 B: C.I. Acid Blue 113

[0057] In addition, the inks are dried for 5 min. using the hot plate at 90° C. and then the processing of curing the resin layer is executed in the oven at 230° C.

[0058] Next, thermosetting resin of two liquid type SS-6699G (manufactured by JSR) is formed in the form of the over coat layer by utilizing the method which was described in Embodiment 1.

[0059] As a result of observing the color filter for the liquid crystal panel thus manufactured using the optical microscope, the faults such as the color mixing, the color shade and the color lack are not observed at all.

[0060] In addition, as a result of manufacturing the liquid crystal panel employing the color filter to drive the resultant liquid crystal panel, the color display can be carried out with the high definition.

COMPARATIVE EXAMPLE 1

[0061] SS-6699G (the maim agent) as two liquid curing type resin and SS-0699G as its curing agent (both of them are manufactured by JSR) are adopted as the coating material, and the substrate in which the three layers low reflective chromium film is formed on the whole surface of a no-alkali glass substrate 1737 (manufactured by Corning Co., Ltd.) of 360 mm×465 mm×0.7 mm is employed as the member to which the coating liquid is to be applied, and the coating is carried out using the coating system having the construction as shown in FIG. 4. As for the quantity measuring pump 43, the high accuracy diaphragm pump is employed. For the driving of the substrate carrier stage 8, the high accuracy servo motor is adopted. The above-mentioned SS-6699G and SS-0699G are uniformly mixed with each other at the volume ratio of 29:6, and then is stored in the coating material tank 41, and also the liquid feeding passage extending up to the nozzle 5 is previously filled with that coating material. In addition, the slit gap is set to 30 &mgr;m and the distance (the clearance) between the tip of the nozzle and the surface of the member to which the coating liquid is to be applied is set to 50 &mgr;m. Also, for the purpose of preventing the coating material from spreading up to the side face and the rear face of the member to be coated with the coating liquid, the crossing width of the discharge opening of the slit tip is set to 356 mm.

[0062] The substrate carrying speed is set to 52 mm/sec, and the flow rate, i.e., the discharge rate of the quantity measuring pump 43 is set to 74.1 &mgr;l/sec, and also the starting point and the end point of the coating fall within the inside from the end portion of the substrate by 1.0 mm. In such a way, the coating is carried out. Then, after the resultant substrate to which the coating liquid was applied has been dried for 20 min. in the oven at 90° C., the baking is further carried out for 60 min. in the oven at 230° C. to obtain the coating film 6.

[0063] The coating material tank 41 is filled with the new coating material, and the coating is continuously carried out at intervals of 1 min. in accordance with the above-mentioned coating method. Then, for 24 hours right after having supplied the new liquid, the substrate to which the coating liquid was applied is pulled out every lapse of 4 hours, and then the number of particles lying on the substrate is measured using the particle counter GI-4700 manufactured by Hitachi Electronics Engineering Co., Ltd. In this connection, for each of the substrates thus pulled out, the number of particles thereon is also previously measured in accordance with the same measuring method before having charged the application system. Then, the number of particles which are considered to be generated in the coating process is measured on the basis of the difference between the two particle measurement results. In this connection, the object of the particle to be measured is in the range of equal to or larger than 1 &mgr;m to smaller than 5 &mgr;m.

[0064] The results of the measurement are shown together with the results of the measurement in Embodiment 1 in Table 1. 3 TABLE 1 Embodiment 1 Comparative Example 1 Number of Particles Number of Particles Elapsed Before After Appl. Before After Appl. Time Appl. Appl. Process Appl. Appl. Process 0 134 149 15 134 149 15 4 76 82 6 76 94 18 8 178 199 21 178 201 23 12 112 128 16 112 145 33 16 146 157 11 146 211 65 20 98 121 23 98 143 45 24 165 177 12 165 234 69

[0065] Considering the above-mentioned measurement results, it becomes clear that in the case of the present comparative example, there is shown the tendency that after having supplied the new liquid, the number of particles is increased with a lapse of time, whereas in the case of Embodiment 1, the mixing is carried out at any time to keep the lapse of time after the mixing to a minimum, whereby it is possible to reduce the generation of the particles in the application process.

COMPARATIVE EXAMPLE 2

[0066] A no-alkali glass substrate 1737 (manufactured by Corning Co., Ltd.) of 360 mm×465 mm×0.7 mm is employed as the member to which the application liquid is to be applied, and SS-6699G (the main agent) as two liquid curing type resin and SS-0699G as its curing agent (both of them are manufactured by JSR) are adopted as the coating material similarly to Comparative Example 1, and the coating film is obtained in accordance with the same coating method as that in Embodiment 1.

[0067] For 24 hours right after the new liquid has been applied, the substrate coated with the coating liquid is pulled out at intervals of 4 hours, and the thickness of the coating film is measured at nine points in the substrate using the tracer method type film thickness measuring apparatus FP-20 manufactured by Tencall Co., Ltd. The results of the measurement are shown together with the results of the measurement in Embodiment 1 in Table 2 with the mean value of the film thickness at the nine points as the central value. 4 TABLE 2 Comparative Embodiment 2 Example 2 Elapsed Time Film Thickness Film Thickness 0 1.09 &mgr;m 1.09 &mgr;m 4 1.07 &mgr;m 1.08 &mgr;m 8 1.08 &mgr;m 1.10 &mgr;m 12 1.07 &mgr;m 1.10 &mgr;m 16 1.09 &mgr;m 1.13 &mgr;m 20 1.07 &mgr;m 1.11 &mgr;m 24 1.09 &mgr;m 1.14 &mgr;m

[0068] Considering the above-mentioned measurement results, it becomes clear that in the case of the present comparative example, there is shown the tendency that after having supplied the new liquid, the film thickness is increased with a lapse of time, whereas in the case of Embodiment 2, the mixing is carried out at any time to keep the lapse of time after the mixing to a minimum, whereby the film thickness is not substantially changed with time and hence the coating is carried out stably.

[0069] In this connection, while in the foregoing, the description has been made with respect to the specific case where the present invention is mainly used in the process of manufacturing the color filter, it is to be understood that the present invention can also be applied when each of the overall coating materials which are limited by the pot life (the time interval for the use), such as the photo resist for use in the manufacture of the semiconductor devices, is applied.

[0070] As set forth hereinabove, according to a coating system and a coating method of the present invention, in the coating with the coating liquid, such as the over coat liquid for the color filter, which is obtained by mixing a plurality of different liquid with one another, the mixing of the liquid can be carried out right before the coating and hence the application can be carried out without any of the limitations for the pot life of the coating liquid. In addition, it is possible to prevent the gel and the like from being generated in the coating liquid supplying passage, and hence any of the coating defects resulting therefrom can be prevented from being generated.

[0071] Further, if the coating method or the coating system according to the present invention is applied to the manufacture of the color filter, then the operation rate of the equipment can be enhanced and also the color filters which are excellent in quality can be manufactured with the high yield.

Claims

1. A coating method in which the coating liquid is discharged on the surface of a member to be coated with the coating liquid by moving relatively a coating head and said member to form a coating film, wherein the process of mixing plural kinds of coating liquid with one another, and the process of supplying the resultant mixed liquid to said coating head are substantially, simultaneously carried out.

2. A coating system having:

a coating liquid supplying apparatus for supplying a coating liquid to a coating head having a slit for discharging therethrough the coating liquid;

a stage for holding a member to be coated with the coating liquid; and

driving means for moving relatively said stage and said coating head, wherein said coating liquid supplying apparatus comprises:

mixing means for mixing equal to or more than two different coating liquid with one another at a fixed ratio; and

mixed liquid supplying means for supplying the resultant mixed liquid to said coating head.

3. A coating system for applying a two liquid mixed type coating liquid to the surface of a member to be coated with the coating liquid to form a coating film, wherein a coating liquid supplying apparatus comprises:

first quantity measuring supply means for supplying a first coating liquid from a first tank to mixing means at a first flow rate;

second quantity measuring supply means for supplying a second coating liquid from a second tank to said mixing means at a second flow rate; and

mixed liquid supplying means for supplying the mixed liquid which has been obtained in said mixing means to a coating head at a third flow rate.

4. A coating system according to claim 3, further comprising a buffer tank for storing therein temporarily the mixed liquid, wherein said mixed liquid supplying means supplies the mixed liquid from said buffer tank to said coating head.

5. A method of manufacturing a color filter substrate, comprising the steps of:

applying a photosensitive resinous composition in accordance with said coating method as defined in claim 1;

patterning said photosensitive resinous composition to form a black matrix pattern; and

giving the gaps of said black matrix pattern coloring inks.

6. A liquid crystal display device comprising:

a color filter substrate which is manufactured in accordance with claim 5;

a counter substrate which is arranged in such a way as to face said color filter substrate; and

a liquid crystal composition with which the space defined between said color filter substrate and said counter substrate is filled.