Color filter manufacturing method, color filter, display apparatus, and apparatus having the display apparatus

In a method of manufacturing a color filter, an ink-jet head discharges ink onto a substrate formed on a surface of an ink receiving layer and colors each pixel of the color filter. The ink-jet head discharges ink onto the position of each pixel by using an alignment mark as a reference which is formed on the ink receiving layer.

BACKGROUND OF THE INVENTION
 The present invention relates to a color filter manufacturing method for
 manufacturing a color filter by using an ink-jet head for discharging ink
 onto a substrate and coloring each pixel of the color filter, a color
 filter manufactured by the method, a display apparatus using the color
 filter and an apparatus including the display apparatus.
 With recent advances in personal computers, especially portable personal
 computers, the demand for liquid crystal displays has risen, especially
 color liquid crystal displays. However, in order to further popularize the
 use of liquid crystal displays, a reduction of cost must be achieved.
 Especially, it is required to reduce the cost of a color filter which
 constitutes a large proportion of the total cost. Various methods have
 been tried to satisfy the required characteristics of color filters while
 meeting the above requirements. However, no method capable of satisfying
 all the requirements has been established. The respective methods will be
 described below.
 The first method is a pigment dispersion method. In this method, a
 pigment-dispersed photosensitive resin layer is formed on a substrate and
 patterned into a single-color pattern. This process is repeated three
 times to obtain R, G, and B color filter layers.
 The second method is a dyeing method. In the dyeing method, a water-soluble
 polymer material as a dyeable material is applied onto a glass substrate,
 and the coating is patterned into a desired shape by a photolithographic
 process. The obtained pattern is dipped in a dye bath to obtain a colored
 pattern. This process is repeated three times to form R, G, and B color
 filter layers.
 The third method is an electrodeposition method. In this method, a
 transparent electrode is patterned on a substrate, and the resultant
 structure is dipped in an electrodeposition coating fluid containing a
 pigment, a resin, an electrolyte, and the like to be colored in the first
 color by electrodeposition. This process is repeated three times to form
 R, G, and B color filter layers. Finally, these layers are calcined.
 The fourth method is a print method. In this method, a pigment is dispersed
 in a thermosetting resin, a print operation is performed three times to
 form R, G, and B coatings separately, and the resins are thermoset,
 thereby forming colored layers. In all of the above methods, a protective
 layer is generally formed on the colored layers.
 The point common to these methods is that the same process must be repeated
 three times to obtain layers colored in three colors, i.e., R, G, and B.
 This causes an increase in cost. In addition, as the number of processes
 increases, the yield decreases. In the electrodeposition method,
 limitations are imposed on pattern shapes which can be formed. For this
 reason, with the existing techniques, it is difficult to apply this method
 to TFTs. In the print method, a pattern with a fine pitch is difficult to
 form because of poor resolution and poor evenness.
 In order to eliminate these drawbacks, methods of manufacturing color
 filters by an ink-jet system are disclosed in Japanese Patent Laid-Open
 Nos. 59-75205, 63-235901, 63-294503 and 1-217320.
 Hereinafter, a method of manufacturing a color filter according to the
 conventional ink-jet printing method is described.
 To manufacture a color filter according to the ink-jet printing method,
 first, a black matrix (BM) is formed on a color filter substrate made of a
 glass substrate or the like. The black matrix (BM) is a light-shielding
 pattern used to clarify partition of each pixel for making a display
 screen clear. The BM is made by forming a metal thin film such as chromium
 or the like on a color filter substrate in correspondence with the pixel
 pattern by sputtering or the like. Next, a predetermined resin composition
 having an ink absorptive characteristic (water absorptive characteristic)
 is coated on the color filter substrate on which the BM is formed, whereby
 forming an ink receiving layer. The ink receiving layer is processed by
 light irradiation or heat treatment, whereby forming a hydrophilic portion
 (water absorptive portion where ink is absorbed) corresponding to pixels
 of a color filter and a water repellent portion (portion where ink is not
 absorbed) serving as a partition wall between pixels of the color filter.
 Then, ink is discharged by an ink-jet head onto the hydrophilic portion of
 the color filter substrate and pixels are colored.
 However, according to the above-described method, positioning deviation is
 sometimes generated between a pattern for the water repellent portion and
 a pattern for the black matrix (BM). The positional offset is caused by
 (1) non-precise BM pattern, (2) alignment offset between the color filter
 substrate and a photo-mask used to form the pattern for water repellent
 portion. When a color filter is manufactured by the ink-jet printing
 method, in order to eliminate color mixture between adjacent pixels or
 white omission, ink must be discharged exactly in the center (portion
 which becomes a pixel of color filter) of two adjacent water repellent
 portions. Conventionally, the ink-jet head is positioned with respect to
 the color filter substrate by using an alignment mark as a reference,
 which is formed on the color filter substrate at the same time the BM
 pattern is formed. Therefore, the ink-jet head is precisely positioned
 with respect to the BM pattern, but if the pattern for the water repellent
 portion and BM pattern deviate as described above, positioning of the
 ink-jet head with respect to the pattern for the water repellent portion
 is offset. If the ink-jet head deviates from the pattern of the water
 repellent portion, defects e.g. color mixture, white omission and the
 like, are likely to occur.
 SUMMARY OF THE INVENTION
 The present invention is made in consideration of the above situation, and
 has as its object to provide a color filter manufacturing method which can
 prevent color mixture or white omission in the pixels of a color filter.
 Another object of the present invention is to provide a color filter
 manufactured by the above manufacturing method, a display apparatus using
 the color filter and an apparatus including the display apparatus.
 In order to solve the above-described problems and attain the
 aforementioned objects, the color filter manufacturing method according to
 the present invention is characterized by the following configuration.
 More specifically, the color filter manufacturing method for manufacturing
 a color filter by using an ink-jet head for discharging ink onto a
 substrate formed on a surface of an ink receiving layer and coloring each
 pixel of the color filter, is characterized in that the ink-jet head
 discharges ink at a position of the each pixel by using a position of a
 predetermined pattern as a reference, formed on the ink receiving layer.
 Furthermore, a color filter according to the present invention is
 characterized by the following configuration according to its first
 aspect.
 Namely, the color filter manufactured by using an ink-jet head for
 discharging ink onto a substrate formed on a surface of an ink receiving
 layer and coloring each pixel of the color filter, is characterized in
 that the ink-jet head discharges ink at a position of each pixel by using
 a position of a predetermined pattern as a reference, formed on the ink
 receiving layer.
 Furthermore, the color filter according to the present invention is
 characterized by the following configuration according to its second
 aspect.
 Namely, the color filter has an alignment mark on an ink receiving layer
 formed on a surface of a color filter substrate.
 Moreover, a display apparatus according to the present invention is
 characterized by the following configuration according to its first
 aspect.
 More specifically, the display apparatus including a color filter
 manufactured by using an ink-jet head for discharging ink onto a substrate
 formed on a surface of an ink receiving layer and coloring each pixel of
 the color filter, is characterized in that the display apparatus
 integratedly comprises: the color filter manufactured by discharging ink
 at a position of the each pixel by using a position of a predetermined
 pattern as a reference, formed on the ink receiving layer; and light
 quantity variable means for varying a quantity of light.
 Furthermore, the display apparatus according to the present invention is
 characterized by the following configuration according to its second
 aspect.
 Namely, the display apparatus integratedly comprises: a color filter having
 an alignment mark on an ink receiving layer formed on a surface of a color
 filter substrate; and light quantity variable means for varying a quantity
 of light.
 Still further, an apparatus including the display apparatus according to
 the present invention is characterized by the following configuration
 according to its first aspect.
 More specifically, the apparatus including a display apparatus having a
 color filter manufactured by using an ink-jet head for discharging ink
 onto a substrate formed on a surface of an ink receiving layer and
 coloring each pixel of the color filter, comprises: image signal supply
 means for supplying the display apparatus with an image signal, wherein
 the display apparatus integratedly comprises: a color filter manufactured
 by discharging ink at a position of each pixel by using a position of a
 predetermined pattern as a reference, formed on the ink receiving layer;
 and light quantity variable means for varying a quantity of light.
 Furthermore, the apparatus including the display apparatus according to the
 present invention is characterized by the following configuration
 according to its second aspect.
 Namely, the apparatus comprises: a display apparatus integratedly
 comprising a color filter having an alignment mark on an ink receiving
 layer formed on a surface of a color filter substrate, and light quantity
 variable means for enabling to vary a quantity of light; and image signal
 supply means for supplying the display apparatus with an image signal.
 Other objects and advantages besides those discussed above shall be
 apparent to those skilled in the art from the description of a preferred
 embodiment of the invention which follows. In the description, reference
 is made to accompanying drawings, which form a part thereof, and which
 illustrate an example of the invention. Such example, however, is not
 exhaustive of the various embodiments of the invention, and therefore
 reference is made to the claims which follows the description for
 determining the scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Preferred embodiments of the present invention will be described in detail
 in accordance with the accompanying drawings.
 FIG. 1 is a perspective view showing the structure of a color-filter
 manufacturing apparatus according to an embodiment of the present
 invention.
 In FIG. 1, reference numeral 51 denotes a platform of the apparatus; 52, an
 XY .theta. stage provided on the platform 51; 53, a color-filter substrate
 set on the XY .theta. stage 52; 54, a color filter formed on the
 color-filter substrate 53; 55, a head unit including R (red), G (green)
 and B (blue) ink-jet heads for coloring the color filter 54; 58, a
 controller which controls the overall operation of a color-filter
 manufacturing apparatus 90; 59, a teaching pendant (personal computer) as
 a display unit of the controller 58; and 60, a keyboard as an operation
 unit of the teaching pendant 59. The head unit 55 is detachably mounted to
 a supporting portion 90a of a color-filter manufacturing apparatus 90,
 with an adjustable rotation angle with respect to the horizontal surface
 direction.
 FIG. 2 is a block diagram showing the construction of a controller which
 controls the operation of the color-filter manufacturing apparatus 90. In
 FIG. 2, the teaching pendant 59 serves as input/output means of the
 controller 58. Numeral 62 denotes a display unit which displays
 information on the progress of manufacturing process, presence/absence of
 abnormality of the ink-jet head and the like. The keyboard 60 serves as an
 operation unit for instructing the operation and the like of the
 color-filter manufacturing apparatus 90.
 Reference numeral 58 denotes a controller which controls the overall
 operation of the color-filter manufacturing apparatus 90; 65, an interface
 unit for receiving/sending data with respect to the teaching pendant 59;
 66, a CPU which controls the color-filter manufacturing apparatus 90; 67,
 a ROM in which control programs for operating the CPU 66 are stored; 68, a
 RAM in which production information and the like are stored; 70, a
 discharge controller which controls ink discharge to respective pixels of
 a color filter; 71, a stage controller which controls the operation of the
 XY .theta. stage 52. The color-filter manufacturing apparatus 90 is
 connected to the controller 58, and operates in accordance with
 instructions from the controller 58.
 FIG. 3 is a perspective view showing the structure of the ink-jet head 55
 used in the above color-filter manufacturing apparatus 90. In FIG. 1, the
 three ink-jet heads IJH are provided in correspondence to the three, R, G
 and B colors, however, as the three heads have the same structure, FIG. 3
 shows the structure of one of these heads.
 In FIG. 3, the ink-jet head IJH mainly comprises a heater board 104 as a
 base plate, a plurality of heaters 102 formed on the heater board 104, and
 a top plate 106 placed on the heater board 104. A plurality of discharge
 orifices 108 are formed on the top plate 106, and tunnel-like liquid
 channels 110 connected to the discharge orifices 108 are formed at the
 rear of the discharge orifices 108. The respective liquid channels 110 are
 separated from each other by partition walls 112. The liquid channels 110
 are connected to a common ink chamber 114 at the rear of the liquid
 channels. Ink is supplied to the ink chamber 114 via an ink supply port
 116, and the ink is supplied from the ink chamber 114 to the respective
 liquid channels 110.
 The heater board 104 and the top plate 106 are assembled such that the
 respective heaters 102 are positioned corresponding to the respective
 liquid channels 110, as shown in FIG. 3. Although FIG. 3 only shows two
 heaters 102, the heaters 102 are respectively provided in correspondence
 to the respective liquid channels 110. In the assembled state as shown in
 FIG. 3, when a predetermined drive pulse is applied to the heaters 102,
 the ink on the heaters 102 is boiled to form bubbles, and the ink is
 pressed due to volume expansion of the bubbles and discharged from the
 discharge orifices 108. Accordingly, the size of the bubbles can be
 controlled by controlling the drive pulse, e.g., the level of electric
 power, applied to the heaters 102. Thus, the volume of the ink discharged
 from the discharge orifices can be freely controlled.
 FIGS. 4 and 5 are cross sections showing the basic structure of a color
 liquid crystal display apparatus 30 incorporating the above-described
 color filter.
 Generally, the color liquid-crystal display device is formed by assembling
 the color filter substrate 1 and an opposing glass substrate 21 and
 filling liquid crystal compound 18 between them. On the inner surface of
 the substrate 21, a TFT (not shown) and transparent pixel electrodes are
 formed in matrix. On the inner surface of the substrate 1, the color
 filter 54 is provided such that the R, G and B colored portions can be
 positioned corresponding to each of the pixel electrodes. A transparent
 counter electrode (common electrode) 16 is formed on the entire surface of
 the color filter 54. Although the black matrix 2 is generally formed on
 the side of the color filter substrate 1 (FIG. 4), in a BM (black matrix)
 on-array type liquid crystal panel, black matrix is formed on the side of
 the TFT substrate (FIG. 5) opposing the color filter substrate. Further,
 an orientation film 19 is formed on the surfaces of the both substrates 1
 and 21. Liquid-crystal molecules can be oriented in a uniform direction by
 rubbing processing on the orientation film 19. Further, polarizing plates
 11 and 22 are attached to the outer surfaces of the respective glass
 substrates. The liquid crystal compound 18 is filled in the joint
 clearance (about 2 to 5 .mu.m) between these glass substrates. As a
 backlight, the combination of a fluorescent light (not shown) and a
 light-scattering plate (not shown) is generally used. The liquid-crystal
 compound functions as an optical shutter to change transmissivity of the
 backlight, which realizes display.
 A case where the above liquid crystal display device is applied to an
 information processing apparatus will be described below with reference to
 FIGS. 6 to 8.
 FIG. 6 is a block diagram showing the schematic arrangement of an
 information processing apparatus serving as a word processor, a personal
 computer, a facsimile apparatus, and a copying machine, to which the above
 liquid crystal display device is applied.
 Referring to FIG. 6, reference numeral 1801 denotes a control unit for
 controlling the overall apparatus. The control unit 1801 includes a CPU
 such as a microprocessor and various I/O ports, and performs control by
 outputting/inputting control signals, data signals, and the like to/from
 the respective units. Reference numeral 1802 denotes a display unit for
 displaying various menus, document information, and image data read by an
 image reader unit 1807, and the like on the display screen; 1803, a
 transparent, pressure-sensitive touch panel mounted on the display unit
 1802. By pressing the surface of the touch panel 1803 with a finger or the
 like, an item input operation, a coordinate position input operation, or
 the like can be performed on the display unit 1802.
 Reference numeral 1804 denotes an FM (Frequency Modulation) sound source
 unit for storing music information, created by a music editor or the like,
 in a memory unit 1810 or an external memory unit 1812 as digital data, and
 reading out the information from such a memory, thereby performing FM
 modulation of the information. Electrical signals from the FM sound source
 unit 1804 are converted into audible sound by a speaker unit 1805. A
 printer unit 1806 is used as an output terminal for a word processor, a
 personal computer, a facsimile apparatus, and a copying machine.
 Reference numeral 1807 denotes an image reader unit for photoelectrically
 reading original data. The image reader unit 1807 is arranged midway along
 the original convey passage and designed to read originals for facsimile
 and copy operations, or other various originals.
 Reference numeral 1808 denotes a transmission/reception unit for the
 facsimile (FAX) apparatus. The transmission/reception unit 1808 transmits
 original data read by the image reader unit 1807 by facsimile, and
 receives and decodes facsimile signals. The transmission/reception unit
 1808 has an interface function for external units. Reference numeral 1809
 denotes a telephone unit having a general telephone function and various
 telephone functions such as an answering function.
 Reference numeral 1810 denotes a memory unit including a ROM for storing
 system programs, manager programs, application programs, fonts, and
 dictionaries, a RAM for storing an application program loaded from the
 external memory unit 1812 and document information, a video RAM, and the
 like.
 Reference numeral 1811 denotes a keyboard unit for inputting document
 information and various commands.
 Reference numeral 1812 denotes an external memory unit using a floppy disk,
 a hard disk, and the like. The external memory unit 1812 serves to store
 document information, music and speech information, application programs
 for the user, and the like.
 FIG. 7 is a perspective view of the information processing apparatus in
 FIG. 6.
 Referring to FIG. 7, reference numeral 1901 denotes a flat panel display
 using the above liquid crystal display device, which displays various
 menus, graphic pattern information, document information, and the like. A
 coordinate input or item designation input operation can be performed on
 the flat panel display 1901 by pressing the surface of the touch panel
 1803 with a finger of the user or the like. Reference numeral 1902 denotes
 a handset used when the apparatus is used as a telephone set. A keyboard
 1903 is detachably connected to the main body via a cord and is used to
 perform various document functions and input various data. This keyboard
 1903 has various function keys 1904. Reference numeral 1905 denotes an
 insertion port through which a floppy disk is inserted into the external
 memory unit 1812.
 Reference numeral 1906 denotes an original insertion table on which an
 original to be read by the image reader unit 1807 is placed. The read
 original is discharged from the rear portion of the apparatus. In a
 facsimile receiving operation or the like, received data is printed by an
 ink-jet printer 1907.
 In a case where the above information processing apparatus serves as a
 personal computer or a word processor, various kinds of information input
 through the keyboard unit 1811 are processed by the control unit 1801 in
 accordance with a predetermined program, and the resultant information is
 output, as an image, to the printer unit 1806.
 In a case where the information processing apparatus serves as a receiver
 of the facsimile apparatus, facsimile information input through the
 transmission/reception unit 1808 via a communication line is subjected to
 reception processing in the control unit 1801 in accordance with a
 predetermined program, and the resultant information is outputted, as a
 received image, to the printer unit 1806.
 In a case where the information processing apparatus serves as a copying
 machine, an original is read by the image reader unit 1807, and the read
 original data is output, as an image to be copied, to the printer unit
 1806 via the control unit 1801. Note that in a case where the information
 processing apparatus serves as a transmitter of the facsimile apparatus,
 original data read by the image reader unit 1807 is subjected to
 transmission processing in the control unit 1801 in accordance with a
 predetermined program, and the resultant data is transmitted to a
 communication line via the transmission/reception unit 1808.
 Note that the above information processing apparatus may be designed as an
 integrated apparatus incorporating an ink-jet printer in the main body, as
 shown in FIG. 8. In this case, the portability of the apparatus can be
 improved. The same reference numerals in FIG. 8 denote parts having the
 same functions as those in FIG. 7.
 &lt;EMBODIMENTS&gt;
 Next, embodiments of the manufacturing method of the color filter according
 to the present invention will be described.
 FIGS. 9A to 9F are cross-sectional views showing an example of a
 color-filter manufacturing process.
 For a color filter of the present invention, it is preferable that a
 transparent substrate be used. Although a glass substrate is generally
 used, it is not limited to a glass substrate as long as the substrate has
 necessary characteristics to be used as a liquid crystal color filter e.g.
 transparency, mechanical strength and the like.
 First, a black matrix (BM) 203 is generated by forming a chromium thin film
 on a substrate 201 by sputtering and performing patterning by
 photolithography process so as to have opening portions (pixel portions).
 Note that any of metal, resin and the like may be used for the black
 matrix. The black matrix may be formed on the opposing substrate.
 Next, a modifiable resin composition layer (ink receiving layer) 202 is
 formed on the substrate 201 (FIG. 9A). An example for the resin
 composition layer used is a material whose ink wettability and/or ink
 absorptivity on a light-irradiated portion is reduced by light irradiation
 or a combination of light-irradiation and heat treatment, while the
 material itself has ink absorptivity. Prebaking may be performed as
 necessary upon forming the resin composition layer. Note that although
 description herein is provided on the resin composition layer processed by
 light irradiation only, a resin composition which reacts to both the light
 irradiation and heat treatment may be used. The resin composition layer
 202 may be formed by various coating methods such as spin coating, roll
 coating, bar coating, spray coating and dip coating, and formation thereof
 is not limited to any specific method. Moreover, although the film
 thickness of the resin composition formed on the substrate can be set
 arbitrarily, it is preferable to form a thickness of 0.4 .mu.m to 2 .mu.m
 in order to uniformly color the substrate by ink-jet printing method.
 Next, pattern exposure using a photo-mask 205 is performed on the resin
 composition layer formed on the black matrix 203, so as to form a water
 repellent portion 204 for repelling color mixture between pixels (FIG.
 9B). At this stage, not only the water repellent portion 204 is formed on
 the black matrix 203, but a predetermined portion besides the effective
 pixel areas is exposed in the shape of an alignment mark so as to form an
 alignment mark 206. The alignment mark 206 may be formed within an
 effective pixel area if that does not cause any inconvenience. Then, using
 the alignment mark 206 as a reference, an ink-jet head 207 and pixel 208
 are positioned, coloring is performed by discharging respective colors of
 ink e.g., R, G and B, by the ink-jet head 207 (FIG. 9C), and the ink is
 dried, if necessary. The positioning of the ink-jet head 207 using the
 alignment mark 206 as a reference is performed by sensing the alignment
 mark 206 by using a television camera via a microscopic lens and detecting
 the position of the alignment mark. The photo-mask 205 used at the time of
 pattern exposure, has opening portions for exposing the resin composition
 layer on the black matrix 203. Taking into consideration the fact that a
 relatively large amount of ink needs to be discharged in order to prevent
 the generating of an uncolored portion at the boundary portion between the
 black matrix 203 and coloring portions, it is preferable to use a mask
 having an opening portion smaller than a light-shielding width of the
 black matrix 203.
 Dyes and pigments are both available for the ink used for coloring. For the
 ink-jet head used in the present invention, a so-called bubble-jet type
 printhead using an electrothermal transducer as an energy generating
 element, or a piezo-jet type printhead using a piezoelectric element can
 be employed. The size of colored area and the coloring pattern can be
 arbitrarily set.
 Next, the colored resin composition is cured (FIG. 9D). The method of light
 irradiation and/or heat treatment are used for curing.
 Then, a protective layer 209 is formed on the resin composition layer 202
 upon necessary to level the layer (FIG. 9E). Note that although leveling
 is realized by the protective layer herein, a flat leveling layer may be
 used, then a protective layer may be formed thereupon. For the protective
 layer and leveling layer, a photo-setting type, thermo-setting type, or
 both photo- and thermo-setting type resin material, inorganic film formed
 by vapor deposition or sputtering and the like are available. As long as
 the material has transparency for a color filter and has sufficient
 durability for ITO formation process and the like performed later, the
 material is usable.
 Next, an ITO film 210 is formed by mask sputtering (FIG. 9F). It is
 preferable to have the film thickness of 1000 .ANG. to 1700 .ANG. where
 the balance between permeability and sheet resistance is excellent.
 Next, the method of detecting the alignment mark 206 and water repellent
 portion 204 formed on the resin composition layer (ink receiving layer)
 202 as described above will be explained with reference to FIGS. 10A to
 10F.
 The water repellent portion is formed by selectively curing the resin by
 irradiating energy light beam on the photosensitive ink receiving layer
 202, as described above. Thus, the water repellent portion can be formed
 in an arbitrary position by exposure using mask or exposure method using
 laser. Then, by performing baking processing, solvent contained in the ink
 receiving layer is volatilized, and curing in the exposed portion is
 promoted. By this, a height difference can be generated between the cured
 portion and non-cured portion. In other words, by preparing an alignment
 mark on the exposure mask for forming the water repellent portion and
 exposing the ink receiving layer, an alignment mark can be formed on the
 ink receiving layer.
 The reflected-light-quantity to incident light ratio at the alignment mark
 portion becomes maximum when the height difference between the height of
 the marked portion (cured portion) and the height of the periphery portion
 (non-cured portion) is 1/4 of the wavelength of light to be detected.
 Therefore, the reflected-light-quantity ratio can be arbitrarily set by
 adjusting the height difference at the alignment mark portion, a light
 source to be detected and an amount of energy used for curing the ink
 receiving layer. Alternately, with an arbitrary light source, the
 reflected-light-quantity ratio can be set by using an optical
 concave-convex detection method, such as the bright field method, dark
 field method, differential interference method and so forth. Moreover, the
 detection precision of an alignment mark, detected at the arbitrary
 reflected-light-quantity ratio, can be improved by performing image
 processing.
 The water repellent portion 204 on the ink receiving layer is linearly
 formed. For the method of detecting the line (water repellent line) of the
 water repellent portion 204 to have the ink-jet head follow the water
 repellent line, a Push-Pull method and the like which is used for tracking
 an optical disc can be applied. More specifically, light which is
 reflected and diffracted by the water repellent line is obtained as an
 output difference between two photoreceptive portions arranged
 symmetrically with respect to the center of the coloring portion. By this,
 a tracking error signal can be detected. Since this method detects the sum
 of zero-order diffraction light and first-order diffraction light, it is
 possible to detect an amount and direction of offset based on interference
 effects of positional offset. Therefore, it is possible to move the
 ink-jet head to follow the water repellent line at high speed and high
 precision. In the case of utilizing the Push-Pull method, it is preferable
 to set the height difference of the water repellent line at 1/8 of the
 laser beam wavelength to be used. This is because, when the height
 difference is 1/4 of the laser beam wavelength, a phase shift of the light
 reflected and diffracted respectively at the water repellent portion and
 coloring portion is .pi., thus the diffracted light interferes with each
 other and is canceled; therefore, no signal is obtained. If there is no
 height difference, the obtained signal will be 0. Accordingly, the
 intermediate height difference, that is, 1/8 of the wavelength is most
 preferable.
 Hereinafter, more specific embodiments are described.
 &lt;First Embodiment&gt;
 A black matrix is generated by forming a chromium film, by sputtering, on a
 surface-polished glass substrate consisting of non-alkali glass to have a
 thickness of 0.2 .mu.m and patterning the film by photolithography process
 so as to have opening portions corresponding to pixels. Then, 3 weight %
 of triphenyl sulfonium hexafluoroantimonate is mixed with 3 weight % of
 acrylic acid, 97 weight % of acrylic copolymer consisting of 49 weight %
 of methyl methacrylate, 29 weight % of hydroxy ethyl methacrylate, 19
 weight % of N-methylol acrylamide. Then, to 83 weight % of this mixture,
 17 weight % of .gamma.-glycidexy propyltrimethoxy silane is mixed. To 15
 weight % of this mixture, 85 weight % of ethyl cellosolve is added, and
 the obtained mixture is coated on the black matrix by spin coating. The
 coated black matrix is dried for ten minutes at 50.degree. C., and as a
 result, a photosensitive resin layer (ink receiving layer) having 1 .mu.m
 thickness is formed.
 Next, the ink receiving layer is exposed through the photo-mask having an
 opening portion smaller than the width of the black matrix as well as an
 opening portion having the shape of the alignment mark outside the
 effective pixel areas. Then, heat treatment is performed at 120.degree. C.
 on a hot plate for 90 seconds. The eight difference at the alignment mark
 formed on the ink receiving layer is 160 nm.
 Furthermore, the alignment mark is sensed by a CCD camera using a laser
 beam having 633 nm wavelength as a light source, image processing is
 performed thereupon, a position of the alignment mark is detected, and the
 ink-jet head is positioned with respect to the glass substrate. Besides a
 laser beam, a halogen light bulb, tungsten light bulb, mercury light bulb,
 xenon light bulb and the like may be used as a light source. Further, in
 order to easily detect a concave or convex portion by optical means, it is
 possible to combine optical detection methods such as dark field method,
 differential interference method, phase difference method and the like
 besides the bright field method.
 Then, respective colors of ink: R (red), G (green) and B (blue), each
 having the following composition, are discharged by the ink-jet head onto
 a unexposed portion (pixel portion) of the ink receiving layer, whereby
 coloring the ink receiving layer.

R ink
 C. I. Acid Red 118: 5 weight %
 ethylene glycol: 20 weight %
 isopropyl alcohol: 5 weight %
 water: 70 weight %
 G ink
 C. I. Acid Green 25: 5 weight %
 ethylene glycol: 20 weight %
 isopropyl alcohol: 5 weight %
 water: 70 weight %
 B ink
 C. I. Acid Blue 113: 5 weight %
 ethylene glycol: 20 weight %
 isopropyl alcohol: 5 weight %
 water: 70 weight %
 The ink receiving layer is dried at 90.degree. C. for 10 minutes, then
 heat-treated at 230.degree. C. for 30 minutes to cure the ink receiving
 layer. Subsequently, a two-pack thermosetting resin material (composition
 consisting of Optomer SS6500 and Optomer SS0500 both manufactured by Japan
 Synthetic Rubber Co. Ltd. mixed at the ratio of 79:21), containing 85% of
 carbitol acetate, is spin-coated thereon to have a film thickness of 1
 .mu.m. The resultant structure is dried at 90.degree. C. for 10 minutes,
 then heat-treated at 230.degree. C. for 30 minutes to cure the coated
 material. As a result, a protective layer is formed. According to the
 above-described method, the ink discharge position of the ink-jet head can
 be set exactly in the middle of two water repellent portions; therefore,
 it is possible to prevent defects caused by deviation of ink discharge
 position.
 The liquid crystal color filter manufactured according to the
 above-described method is inspected with an optical microscope. As a
 result, defects such as color mixture or white omission on the filter have
 greatly decreased.
 Furthermore, an ITO film is mask-sputtered by using an in-line sputtering
 apparatus, and a color filter is generated. By using the color filter, a
 TFT liquid crystal panel is generated.
 &lt;Second Embodiment&gt;
 As shown in FIGS. 11A to 11F, an Al film 211 relatively larger than the
 alignment mark is sputtered to have a thickness of 500 angstrom on the
 portion of the glass substrate where the alignment mark is formed in the
 first embodiment. By this, the alignment mark can be easily seen on the
 resin composition layer. Besides this point, a color filter is
 manufactured similarly to that in the first embodiment.
 &lt;Third Embodiment&gt;
 In place of Al film used in the second embodiment, Au, Ag, Cu, Ni and Cr
 film are respectively sputtered so that the alignment mark can be easily
 seen. Besides this point, a color filter is manufactured similarly to that
 in the second embodiment.
 &lt;Fourth Embodiment&gt;
 In place of Al film used in the second embodiment, a Cr film, the same
 material as the black matrix, is used. The Cr film is formed at the same
 time as the formation of the black matrix. Besides the Cr film, a color
 filter is manufactured similarly to that in the second embodiment.
 &lt;Fifth Embodiment&gt;
 As shown in FIGS. 12A to 12G, ink is discharged in the periphery of the
 alignment mark formed on the resin composition layer by exposure, so that
 a coloring portion 212 where the alignment mark can be easily seen is
 formed. Besides this point, a color filter is manufactured similarly to
 that in the first embodiment.
 &lt;Sixth Embodiment&gt;
 A glass substrate, on which a metal film is formed in the manner similar to
 that of the third embodiment, is used in the sixth embodiment. Besides
 this point, a color filter is manufactured similarly to that in the fourth
 embodiment.
 &lt;Seventh Embodiment&gt;
 The water repellent line is formed on the ink receiving layer so as to have
 a height difference of 80 nm. As to optical control, while performing
 focus control by utilizing an optical unit adopting a method of
 astigmatism, comprising an object lens, a detection lens, a cylindrical
 lens and a four-partitioned photoreceptive portion, tracking control is
 performed according to the Push-Pull method using laser having 633 nm as a
 light source. At this stage, an ink-jet head, integrating a focus and
 tracking unit, is mechanically moved to the neighborhood of the
 coloring-start position. The water repellent line at the end of the
 coloring-start position is detected by the focus and tracking unit and the
 ink-jet head is moved to follow the water repellent line. While the
 ink-jet head follows the water repellent line, respective colors of ink R,
 G, B are discharged by the ink-jet head to the unexposed portion (pixel
 portion), coloring the ink receiving layer. Besides the above-described
 point, a color filter is manufactured in the manner similar to that of the
 first embodiment.
 According to the above method, aligning the ink-jet head with the substrate
 is unnecessary at the time of coloring operation. In addition, since the
 position of the ink-jet head can be corrected by optical position
 detection, the size of the apparatus can be reduced. As a result,
 productivity can be greatly improved.
 Furthermore, since the coloring position is specified by following the
 water repellent line, even a very little positional offset due to a
 difference in exposure mask can be corrected.
 The liquid crystal color filter manufactured according to the
 above-described method is inspected by an optical microscope. As a result,
 defects such as color mixture or white omission on the filter have greatly
 decreased. Accordingly, yield in color filter manufacturing is greatly
 increased.
 &lt;Comparative Example&gt;
 Instead of the alignment mark formed on the resin composition layer by
 exposure processing, an alignment mark directly formed on the glass
 substrate is used to position the ink-jet head. Besides this point, a
 color filter is manufactured similarly to that in the first embodiment.
 FIG. 13 shows the results of inspecting color filters by an optical
 microscope, respectively manufactured according to the aforementioned
 first to seventh embodiments and the comparative example.
 As can be seen from FIG. 13, the color filter manufactured according to the
 first to seventh embodiments, where the ink-jet head is positioned with
 the use of the alignment mark and water repellent line formed on the resin
 composition layer as a reference, is less likely to have color mixture or
 white omission, and has higher yield in the color filter manufacturing, as
 compared to the color filter manufactured according to the comparative
 example where the alignment mark directly formed on the glass substrate is
 used as a reference for positioning. Moreover, the manufacturing methods
 according to the second to sixth embodiments, where the alignment mark is
 made easy to see, have higher yield in color filter manufacturing as
 compared to the method according to the first embodiment where the
 alignment mark is simply formed on the resin composition layer.
 Furthermore, a TFT liquid crystal panel is manufactured by using the color
 filter which has been considered "excellent" as a result of the
 aforementioned inspection using a microscope. As a result, a panel capable
 of highly precise color displaying is realized.
 FIGS. 14A and 14B show the mechanism that, in a case where the pattern for
 the black matrix and pattern for the water repellent portion are deviated,
 color mixture or white omission is less likely to occur when the alignment
 mark formed on the resin composition layer is used for positioning an
 ink-jet head as described in the present invention than to use an
 alignment mark formed on the glass substrate as conventionally suggested.
 More specifically, as shown in the conventional example in FIG. 14A, in a
 case where an alignment mark is formed on the glass substrate and an
 ink-jet head is positioned using the black matrix (BM) as a reference, if
 the pattern of the water repellent portion is deviated from the pattern of
 the black matrix, ink discharged by the ink-jet head is deviated from the
 ink absorptive portion.
 On the contrary, according to the present invention, a light-transmitting
 portion for forming an alignment mark is formed on the photo-mask serving
 as a pattern for forming the water repellent portion. Therefore, there is
 almost no positional deviation between the alignment mark and the pattern
 of the water repellent portion on the resin composition layer.
 Accordingly, by making use of the alignment mark to position the ink-jet
 head, the ink-jet head can discharge ink precisely at the water absorptive
 portion between the water repellent portions.
 Each of the embodiments described above has exemplified a printer, which
 comprises means (e.g., an electrothermal transducer, laser beam generator,
 and the like) for generating heat energy as energy utilized upon execution
 of ink discharge, and causes a change in state of ink by the heat energy,
 among the ink-jet printers. According to this ink-jet printer and printing
 method, a high-density, high-precision printing operation can be attained.
 As the typical arrangement and principle of the ink-jet printing system,
 one practiced by use of the basic principle disclosed in, for example,
 U.S. Pat. Nos. 4,723,129 and 4,740,796 is preferable. The above system is
 applicable to either one of a so-called on-demand type and a continuous
 type. Particularly, in the case of the on-demand type, the system is
 effective because, by applying at least one driving signal, which
 corresponds to printing information and gives a rapid temperature rise
 exceeding film boiling, to each of electrothermal transducers arranged in
 correspondence with a sheet or liquid channels holding a liquid (ink),
 heat energy is generated by the electrothermal transducer to effect film
 boiling on the heat acting surface of the printhead, and consequently, a
 bubble can be formed in the liquid (ink) in one-to-one correspondence with
 the driving signal. By discharging the liquid (ink) through a discharge
 opening by growth and shrinkage of the bubble, at least one droplet is
 formed. If the driving signal is applied as a pulse signal, the growth and
 shrinkage of the bubble can be attained instantly and adequately to
 achieve discharge of the liquid (ink) with the particularly high response
 characteristics.
 As the pulse-form driving signal, signals disclosed in U.S. Pat. Nos.
 4,463,359 and 4,345,262 are suitable. Note that further excellent printing
 can be performed by using the conditions described in U.S. Pat. No.
 4,313,124 of the invention which relates to the temperature rise rate of
 the heat acting surface.
 As an arrangement of the printhead, in addition to the arrangement as a
 combination of discharge nozzles, liquid channels, and electrothermal
 transducers (linear liquid channels or right angle liquid channels) as
 disclosed in the above specifications, the arrangement using U.S. Pat.
 Nos. 4,558,333 and 4,459,600, which disclose the arrangement having a heat
 acting portion arranged in a flexed region is also included in the present
 invention. In addition, the present invention can be effectively applied
 to an arrangement based on Japanese Patent Laid-Open No. 59-123670 which
 discloses the arrangement using a slot common to a plurality of
 electrothermal transducers as a discharge portion of the electrothermal
 transducers, or Japanese Patent Laid-Open No. 59-138461 which discloses
 the arrangement having an opening for absorbing a pressure wave of heat
 energy in correspondence with a discharge portion.
 Furthermore, as a full line type printhead having a length corresponding to
 the width of a maximum printing medium which can be printed by the
 printer, either the arrangement which satisfies the full-line length by
 combining a plurality of printheads as disclosed in the above
 specification or the arrangement as a single printhead obtained by forming
 printheads integrally can be used.
 In addition, not only an exchangeable chip type printhead, as described in
 the above embodiment, which can be electrically connected to the apparatus
 main unit and can receive ink from the apparatus main unit upon being
 mounted on the apparatus main unit but also a cartridge type printhead in
 which an ink tank is integrally arranged on the printhead itself can be
 applicable to the present invention.
 It is preferable to add recovery means for the printhead, preliminary
 auxiliary means, and the like provided as an arrangement of the printer of
 the present invention since the printing operation can be further
 stabilized. Examples of such means include, for the printhead, capping
 means, cleaning means, pressurization or suction means, and preliminary
 heating means using electrothermal transducers, another heating element,
 or a combination thereof. It is also effective for stable printing to
 provide a preliminary discharge mode which performs discharge
 independently of printing.
 Moreover, in each of the above-mentioned embodiments of the present
 invention, it is assumed that the ink is liquid. Alternatively, the
 present invention may employ ink which is solid at room temperature or
 less, or ink which softens or liquefies at room temperature, or ink which
 liquefies upon application of a printing signal.
 In addition, in order to prevent a temperature rise caused by heat energy
 by positively utilizing it as energy for causing a change in state of the
 ink from a solid state to a liquid state, or to prevent evaporation of the
 ink, ink which is solid in a non-use state and liquefies upon heating may
 be used. In any case, ink which liquefies upon application of heat energy
 according to a printing signal and is discharged in a liquid state, ink
 which begins to solidify when it reaches a printing medium, or the like,
 is applicable to the present invention. In this case, ink may be situated
 opposite to electrothermal transducers while being held in a liquid or
 solid state in recess portions of a porous sheet or through holes, as
 described in Japanese Patent Laid-Open No. 54-56847 or 60-71260. In the
 present invention, the above-mentioned film boiling system is most
 effective for the above-mentioned inks.
 As has been described above, the present invention enables to prevent color
 mixture or white omission on a color filter and greatly improve yield in
 color filter manufacturing.
 The present invention is not limited to the above embodiments and various
 changes and modifications can be made within the spirit and scope of the
 present invention. Therefore, to appraise the public of the scope of the
 present invention, the following claims are made.