Various methods of manufacture of electro-optical panels, etc. involving a device and method of discharging liquid drops of an alignment film in a single pass from plural nozzles of a drop discharge head

A method is provided of discharging liquid drops of an alignment film from a corresponding plurality of nozzles arranged with a predetermined interval in the direction Y that crosses a scanning direction X by scanning a liquid drop discharge head having the plurality of nozzles in the scanning direction. The liquid drops of the alignment film are discharged to a coated area to be coated with the alignment film by scanning the liquid drop discharge head once. The coated area corresponds to the entire display panel of a single panel or the entire area in which the alignment film is to be formed in a single chip.

RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2003-142044 filed May 20, 2003 which is hereby expressly incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to a method of discharging liquid drops of an alignment film, a method of manufacturing an electro-optical panel, a method of manufacturing an electronic apparatus, a program, a device for discharging liquid drops of an alignment film, an electro-optical panel, and an electronic apparatus.

2. Description of the Related Art

Dispensers are provided as devices for applying liquid crystal within a region surrounded by a sealing material during manufacturing of liquid crystal panels. When dispensers are used, it is possible to drop the liquid crystal with a certain degree of precision and to a certain amount. However, when the liquid crystal of an amount equal to or less than that amount is dropped, there is insufficient reliability with respect to the degree of precision of the discharge amount. When the dispensers drop the liquid crystal, the drops directly become spots.

In Japanese Unexamined Patent Application Publication No. 5-281562, a method of manufacturing a liquid crystal panel using an inkjet method, in which the amount of a drop is extremely small and the drops can be discharged with a high degree of precision, is disclosed. According to the above publication, the main body of the inkjet for discharging the liquid crystal drops is scanned in lines with a pitch 0.5 mm to thus apply the liquid crystal drops to a substrate in lines.

When a substrate is coated with liquid including a material of an alignment film by an inkjet method, like in the conventional art, the liquid (the material of the alignment film) discharged from a nozzle of an inkjet head (hereinafter, only a head in some cases) is arranged on the substrate drop by drop. When the head includes a plurality of nozzles, it is possible to perform wide range drawing by performing scanning once by the amount in which the plurality of nozzles exists.

It is not possible to perform drawing by performing scanning once in the region that exceeds the range of the plurality of nozzles formed in the head. Therefore, in such a region, the portion that cannot be drawn by performing first scanning is drawn during performing second scanning to coat an entire desired coated area. However, when the portion that cannot be drawn by the first scanning is drawn during the second scanning, dropping (coating) spots of the material of the alignment film (the liquid) are generated.

In order to solve the above problems, it is an object of the present invention to provide a method of discharging liquid drops of an alignment film, a device for discharging liquid drops of an alignment film, and an electro-optical panel, in which lines or spots are not generated in an electro-optical panel coated with the alignment film by a method of discharging liquid drops including the ink jet method.

It is another object of the present invention to provide a method of discharging liquid drops of an alignment film, a device for discharging liquid drops of an alignment film, and an electro-optical panel, in which the quality of an electro-optical panel coated with the alignment film by a method of discharging liquid drops including the inkjet method does not deteriorate.

SUMMARY

In order to solve the above problems, the present invention provides a method of discharging liquid drops of an alignment film from a corresponding plurality of nozzles arranged with a predetermined interval in a direction that crosses a scanning direction by scanning a liquid drop discharge head having the plurality of nozzles in the scanning direction. The liquid drops of the alignment film are discharged by scanning the liquid drop discharge head to a coated area to be coated with the alignment film once.

The present invention also provides a method of discharging liquid drops of an alignment film from a corresponding plurality of nozzles arranged with a predetermined interval in a direction that crosses a scanning direction by scanning a liquid drop discharge head having the plurality of nozzles from a specific position in a sub-scanning direction that crosses the scanning direction to the scanning direction. The liquid drops of the alignment film are discharged so that an interface between the alignment film and air is not generated in a position corresponding to the boundary portion of the alignment film discharged by scanning the liquid drop discharge head before and after the sub-scanning operation of the liquid drop discharge head in a coated area to be coated with the alignment film.

In the method of discharging liquid drops of an alignment film according to the present invention, a plurality of the coated areas are provided in a direction that crosses the scanning direction, and control is performed so that, when the liquid drop discharge head is scanned once in a predetermined time, the liquid drops of the alignment film are discharged from the nozzle of the plurality of nozzles corresponding to the first coated area whose entire surface is coated by performing the scanning in the predetermined time to the first coated area, and the liquid drops of the alignment film are not discharged from the nozzle of the plurality of nozzles corresponding to the second coated area whose entire surface is not coated by performing the scanning in the predetermined time to the second coated area.

In the method of discharging liquid drops of an alignment film according to the present invention, the liquid drops of the alignment film are discharged to the entire surface of the second coated area by scanning the liquid drop discharge head once in the time next to the predetermined time.

In the method of discharging liquid drops of an alignment film according to the present invention, a boundary between the first coated area and the second coated area is obtained based on the width of the region to be coated with the alignment film in the coated area.

In the method of discharging liquid drops of an alignment film according to the present invention, a boundary between the first coated area and the second coated area is obtained based on the distance between the regions to be coated with the alignment film in the adjacent coated areas.

In the method of discharging liquid drops of an alignment film according to the present invention, when the width of the region to be coated with the alignment film in the coated area is d1, the distance between the regions to be coated with the alignment film in the adjacent coated areas is d2, and the length between the nozzle at one end of the liquid drop discharge head in the direction that crosses the scanning direction and the nozzle at the other end thereof is L, the maximum value of n that satisfies the following equation n×d1+(n−1)×d2≦L is obtained and the boundary between the first coated area and the second coated area is obtained based on the maximum value of n.

The present invention also provides a method of discharging liquid drops of an alignment film from a corresponding plurality of nozzles arranged with a predetermined interval in a direction that crosses a scanning direction by scanning a liquid drop discharge head having the plurality of nozzles in the scanning direction. The method comprising the steps of: (a) connecting a plurality of the liquid drop discharge heads each having a size that is not allowed to completely discharge the liquid drops of the alignment film to a coated area to be coated with the alignment film by performing the scanning once, to each other, to form a liquid drop discharge head connecting body; and (b) discharging the liquid drops of the alignment film from the corresponding plurality of nozzles of the liquid drop discharge head connecting body to the entire surface of the coated area by scanning the liquid drop discharge head connecting body once.

In the method of discharging liquid drops of an alignment film according to the present invention, the coated area corresponds to the entire display area of a single panel or the entire area in which an alignment film is to be formed in a single chip.

The present invention also provides a method of manufacturing an electro-optical panel, comprising the steps: (c) discharging liquid drops of a color filter material from a liquid drop discharge head to a base member; and (d) discharging liquid drops of an alignment film from the liquid drop discharge head to the color filter. In the step (d), the liquid drop discharge head having a plurality of nozzles arranged with a predetermined interval in a direction that crosses a scanning direction is scanned in the scanning direction to discharge the liquid drops of the alignment film from the corresponding plurality of nozzles to a coated area to be coated with the alignment film by scanning the liquid drop discharge head once.

A method of manufacturing an electronic apparatus according to the present invention comprises the step of manufacturing an electronic apparatus by mounting surface-mounted components on an electro-optical panel manufactured by the method of manufacturing the above-mentioned electro-optical panel according to the present invention.

The present invention also provides a program for making a computer execute operations of scanning a liquid drop discharge head having a plurality of nozzles arranged with a predetermined interval in a direction that crosses a scanning direction to discharge the liquid drops of an alignment film from the corresponding plurality of nozzles to a plurality of coated areas provided in a direction that crosses the scanning direction and to be coated with an alignment film. The computer executes the following steps: (e) scanning the liquid drop discharge head once to the coated area to discharge the liquid drops of the alignment film; and (f) when the liquid drop discharge head is scanned once in a predetermined time, controlling so as to discharge the liquid drops of the alignment film from the nozzle of the plurality of nozzles corresponding to the first coated area whose entire surface is coated by performing the scanning in the predetermined time to the first coated area and so as not discharge the liquid drops of the alignment film from the nozzle of the plurality of the nozzles corresponding to the second coated area whose entire surface is not coated by performing the scanning in the predetermined time to the second coated area.

The present invention also provides a device for discharging liquid drops of an alignment film, comprising: a liquid drop discharge head having a plurality of nozzles arranged with a predetermined interval in a direction that crosses a scanning direction; and a control unit. The liquid drop discharge head is scanned from a specific position in a sub-scanning direction that crosses the scanning direction to the scanning direction to discharge the liquid drops of the alignment film from the corresponding plurality of nozzles. When the alignment film is discharged by scanning the liquid drop discharge head before and after performing the sub-scanning, the control unit controls so as to discharge the liquid drops of the alignment film by scanning the liquid drop discharge head once to the coated area so that an interface between the alignment film and air is not generated in the position corresponding to the boundary of the alignment film discharged by performing the scanning before and after performing the sub-scanning of the liquid drop discharge head in the coated area to be coated with the alignment film.

The present invention also provides a device for discharging liquid drops of an alignment film, comprising: a liquid drop discharge head having a plurality of nozzles arranged with a predetermined interval in a direction that crosses a scanning direction; and a control unit. The liquid drop discharge head is scanned in the scanning direction to discharge the liquid drops of the alignment film from the corresponding plurality of nozzles to a plurality of coated areas provided in a direction that crosses the scanning direction and to be coated with the alignment film by scanning the liquid drop discharge head once. When the liquid drop discharge head is scanned once in a predetermined time, the control unit controls so as to discharge the liquid drops of the alignment film from the nozzle of the plurality of nozzles corresponding to the first coated area whose entire surface is coated by performing the scanning in the predetermined time to the first coated area and so as not to discharge the liquid drops of the alignment film from the nozzle of the plurality of nozzles corresponding to the second coated area whose entire surface is not coated by performing the scanning in the predetermined time to the second coated area.

The present invention also provides an electro-optical panel comprising: a substrate; and a thin film on the substrate, which is formed of liquid drops of an alignment film discharged from a liquid drop discharge head. The liquid drop discharge head having a plurality of nozzles arranged with a predetermined interval in a direction that crosses a scanning direction is scanned in the scanning direction to discharge the liquid drops from the corresponding plurality of nozzles to the coated area to be coated with the alignment film by scanning the liquid drop discharge head once.

An electro-optical device according to the present invention comprises the above-mentioned electro-optical panel according to the present invention.

An electronic apparatus according to the present invention comprises the electro-optical device according to the present invention.

DETAILED DESCRIPTION

The embodiments of the present invention will now be further described with reference to the drawings. Also, the present invention is not restricted by the embodiments. A liquid crystal panel can be used as an electro-optical panel according to the present invention.

FIRST EMBODIMENT

A method of dropping liquid drops of an alignment film by an inkjet method will now be described as an embodiment of a method of discharging liquid drops of liquid substance according to the present invention. According to the first embodiment, a technology of preventing the generation of striped display unevenness when the liquid drops of the alignment film is dropped by an inkjet method is provided.

First, a liquid crystal panel (an electro-optical panel100) manufactured by the method of applying the liquid crystal according to the present embodiment will now be described with reference toFIG. 1.

As illustrated inFIG. 1, in the electro-optical panel100, liquid crystal12is sealed between a color filter substrate10ain which color filters11are formed on the surface of a base member1and a counter substrate10bthat faces the color filter substrate10a. Spacers13are arranged between the color filter substrate1Oaand the counter substrate10b. The distance t between the two substrates is maintained uniform over the entire surface.

In the color filter substrate10a, a color filter protecting film20(hereinafter, a CF protecting film) is formed to thus protect the color filters11formed on the base member1. An ITO14and an alignment film16are formed on the CF protecting film20. The CF protecting film20protects the color filters11from the high temperature at which the ITO14is formed and planarizes the concavo-convex portions among the color filters11to thus prevent the ITO14from being short-circuited and the alignment film16from being poorly rubbed.

FIGS. 2 and 3illustrate a method of manufacturing an electro-optical panel and an electronic apparatus according to the present embodiment.FIG. 4is a flowchart illustrating the method of manufacturing the electro-optical panel and the electronic apparatus according to the present embodiment.FIG. 5illustrates a device for discharging liquid drops according to the present embodiment.

First, as illustrated inFIG. 2(a), the color filters11are formed by discharging the liquid drops onto the base member1by photolithography, an inkjet method, or a plunger (step S101).

Then, in order to improve the wettability of the color filters11and the liquid protecting film material with which the color filters11are coated, as illustrated inFIG. 2(b), a surface-reforming process is performed on the color filters11(step S102) to thus improve the wettability of the protecting film material. This is because, when the wettability is poor, the protecting film material easily coheres so that the color filters11are not uniformly coated with the protecting film material. Also, the protecting film material does not easily permeate into spaces among the color filters11so that bubbles may be generated in the spaces and the quality of displayed images of the electro-optical panel may thus deteriorate. According to the present embodiment, the surface-reforming process is performed by radiating ultraviolet (UV) rays onto the surfaces of the color filters11using a UV lamp3. However, an oxygen plasma process may be performed. In particular, according to the oxygen plasma process, it is possible to remove residue on the color filter11and to thus improve the quality of the CF protecting film20.

The wettability of the color filters11and the liquid protecting film material with which the color filters11are coated can be defined by the contact angle β of the protecting film material with respect to the color filter11(refer toFIG. 2(c)). According to the method of manufacturing the electro-optical panel of the present embodiment, the contact angle β is preferably equal to or less than 10°. When the contact angle β is in this range, since it is possible to permeate enough protecting film material into the spaces among the color filters11and to form the protecting film material on the color filters11to a uniform thickness, it is possible to form a high quality CF protecting film20.

When the surface-reforming process is completed, as illustrated inFIG. 2(d), the color filters11are coated with the liquid protecting film material by discharging the liquid drops (step S103).

Here, the color filters11are coated with the protecting film material by discharging the liquid drops by the inkjet method. The method of applying the liquid drops of the protecting film material and the method of arranging the liquid drops may be the same as the following methods of applying an alignment film and arranging liquid drops. Also, instead of the following methods of applying an alignment film and arranging liquid drops, a method of applying the liquid drops of the well-known protecting film material by the inkjet method and a method of arranging the liquid drops may be adopted.

When the color filter substrate10ais coated with the protecting film material, in order to volatilize solvents in the protecting film material, the protecting film material is dried (step S104). According to the present embodiment, as illustrated inFIG. 2(e), the base member1coated with the liquid drops of the protecting film material is put on a hot plate67to thus volatilize the solvents in the protecting film material. At this time, in order to planarize the surface of the CF protecting film20, the protecting film material is preferably dried at a low temperature for a certain time. Specifically, the protecting film material is preferably dried at a temperature equal to or less than 70° C. for no less than 5 minutes. In order to further planarize the surface of the CF protecting film20, the protecting film material is preferably dried at a temperature equal to or less than 50° C. for no less than 10 minutes and at a temperature equal to or less than 30° C. for no less than 1 hour. Also, the protecting film material may be dried by an infrared heater or an oven as well as by the hot plate67. By doing so, the solvents in the protecting film material are volatilized to thus form the CF protecting film20in the color filter substrate10a.

Then, as illustrated inFIG. 3(f), the ITO14and the alignment film16are formed on the CF protecting film20(step S105).

Here, how the alignment film is applied will be described with reference toFIG. 5.

According to the present embodiment, the liquid crystal drops are discharged by the inkjet method. As illustrated inFIG. 5(a), a liquid drop discharging device50includes a liquid drop discharge head52and a stage60. The alignment film material (3% of polyimide resin, and 97% of solvent) is supplied from a tank56to the liquid drop discharge head52through a supply tube58.

As illustrated inFIG. 5(b), a plurality of nozzles54are arranged with an arrangement width H and with a uniform pitch P. Also, each nozzle54includes a piezoelectric element (not shown) in the liquid drop discharge head52. The liquid drops of alignment film material are discharged from arbitrary nozzles54under the control of a control device65. Also, it is possible to change the amount of the alignment film material discharged from the nozzles54by changing a driving pulse formed to the piezoelectric elements. Also, a personal computer or a workstation may be used as the control device65.

An example of the structure of the liquid drop discharge head52will be described with reference toFIGS. 6 and 7. As illustrated inFIGS. 6 and 7, the liquid drop discharge head52includes a nozzle plate131and a vibration plate132that are made of stainless steel so that the nozzle plate131and the vibration plate132are connected to each other through a partitioning member (a reservoir plate)133. A plurality of spaces134and a liquid reservoir135are formed between the nozzle plate133and the vibration plate132by the partitioning member. The spaces134and the liquid reservoir135are filled with a liquid material (not shown) and communicate with each other through a supply port136. Also, a nozzle54that is a minute hole is formed in the nozzle plate131for jetting a liquid material111from the spaces134. On the other hand, a hole137for supplying the liquid material111to the liquid reservoir135is formed in the vibration plate132.

As illustrated inFIGS. 6 and 7, piezoelectric elements138are attached to the other surface of the vibration plate132, which is opposite to the surface that faces the spaces134. As illustrated inFIG. 7, the piezoelectric element138is positioned between a pair of electrodes139,139so that the piezoelectric element138is curved to protrude outside when the pair of electrodes139is charged with electricity. The vibration plate132to which the piezoelectric elements138having the above structure are attached is integrated with the piezoelectric elements138to thus be curved to protrude outside so that the volume of the spaces134increases. Therefore, the liquid material whose amount corresponds to the increased amount of the volume of the spaces134is received from the liquid reservoir135through the supply port136. Also, when the flow of the electricity to the piezoelectric elements138is stopped in such a state, the piezoelectric elements138and the vibration plate132recover their original shapes. Therefore, since the spaces134also recover their original volume, the pressure of the liquid material111in the spaces134increases so that the jet liquid drops of the liquid material are discharged from the nozzles54to the base member1.

Methods other than the piezo jet type using the piezoelectric elements as mentioned above may be used as a method of the liquid drop discharge head52. Also, the alignment film material, which is the coating liquid, may be jetted from the minute hole by generating vibrations by a supersonic motor and a linear motor or by applying pressure to the tank. Here, the alignment film material in the tank is preferably defoamed in advance. Also, the liquid drop discharge head52may be formed by a bubble (R) jet method in which the alignment film material in the tank or a mixture of the alignment film material and low viscosity volatile liquid is heated to thus jet the alignment film material from the minute hole by the expansion and foaming of the above material.

The liquid drop discharge head52can rotate around a rotation shaft A using the rotation shaft A orthogonal to the head center as a rotation center. As illustrated inFIG. 5(c), when the liquid drop discharge head52is rotated around the rotation shaft A and an angle θ is formed between the direction in which the nozzles54are arranged and the direction X, it is possible to make the pitch of the nozzles54P′=P×Sin θ. Therefore, it is possible to change the pitch of the nozzles54in accordance with regions coated with the alignment film material or conditions under which the regions are coated with the alignment film material. A substrate1having transparent electrodes on which an alignment process is performed is provided on a stage60. The stage60can move in the direction Y (the sub-scanning direction) and can rotate around a rotation shaft B using the rotation shaft B orthogonal to the center of the stage60as a rotation center.

The liquid drop discharge head52reciprocates in the direction X (the main scanning direction) in the drawing while discharging the liquid drops of the alignment film material on the alignment film16with the arrangement width H of the nozzles54. When the alignment film material is applied by performing scanning once, the stage60moves in the direction Y by the arrangement width H of the nozzles54and the liquid drop discharge head52discharges the alignment film material to the next region. The operation of the liquid drop discharge head52, the discharge of the nozzles54, and the operation of the stage60are controlled by the control device65. When the operation patterns are programmed in advance, it is possible to easily change the pattern in which the regions are coated with the alignment film material in accordance with the regions coated with the alignment film material or the conditions under which the regions are coated with the alignment film material. It is possible to coat all regions to be coated with the alignment film material by repeating the above operations.

The pitch of the nozzles54of the liquid drop discharge head52and the scanning pitch in the main scanning direction (the drawing direction) will now be described with reference toFIG. 8.

FIG. 8is a plan view illustrating a state in which the liquid drops of the alignment film material discharged from the liquid drop discharge head52are dropped. The liquid drops of the alignment film material are dropped onto an ITO14of the color filter substrate10aby a distance of 10 μm in the main scanning direction (the direction X) and by a distance of 100 μm in the sub-scanning direction (the direction Y). In this case, the distance y of the liquid drops in the sub-scanning direction is the same as the pitch P of the nozzles54. The distance x of the liquid drops in the main scanning direction is dependent on the scanning speed and the discharge frequency of the liquid drop discharge head52.

Next, the arrangement of the liquid drops of the alignment film material discharged in the inkjet method according to the present embodiment will now be described.

As illustrated inFIG. 25, the head52in which the plurality of nozzles54are provided is scanned with respect to the base member1in the direction of the arrow Ya to discharge the liquid drops of the material of the alignment film16from the corresponding nozzles54in the direction of the arrow Yb. By doing so, when the liquid crystal panel completed through predetermined processes after forming the alignment film16on the base member1, is lightened, lines (spots)154are generated in the base member1along the drawing direction.

First, the experiment illustrated inFIG. 25will be described with reference toFIGS. 9 and 10.FIG. 9is a side view illustrating the liquid drop discharge head52used for the experiment ofFIG. 25and a state of liquid drops71on the base member1.FIG. 10is a plan view ofFIG. 9.

When the liquid drops of the alignment film material are discharged from the nozzles54of the head52and are dropped onto the base member1, the liquid drops spread to be circular in a moment centering around the applying points so that the liquid drops71each having a predetermined diameter da are formed. As illustrated inFIGS. 9 and 10, when the adjacent liquid drops71contact each other, the liquid drops71are connected to each other from the contact position so that the liquid drops71are integrated with each other to thus form a single thin film72as illustrated inFIG. 11.

Therefore, in order to form the single thin film72, it is necessary to set the pitch p1between the nozzles54so that the adjacent liquid drops71contact each other. According to the present example, since the diameter da of each liquid drop71spreading on the base member1is 100 μm corresponding to the amount of the alignment film material per a drop discharged from each nozzle54, the pitch p1between the nozzles54is set to 100 μm.

As a result of the experiment, when the liquid drops of the alignment film material are discharged from the nozzles54the pitch p1between which is set as mentioned above, the liquid drops71are connected to each other to thus be integrated with each other as assumed. As a result, the single thin film72illustrated inFIG. 11is obtained. At this point of time that is an experiment process, the thin film72that covers a desired range is formed so that no special problems seem to exist. However, when a liquid crystal panel is created by performing the following predetermined processes. (steps S109to S111) and the liquid crystal panel is illuminated, the lines or spots154are generated as illustrated inFIG. 25.

Next, the state of the alignment film material from the moment at which the alignment film material is discharged from the nozzle54of the head52to the moment at which the alignment film material is placed on the base member1will now be described with reference toFIG. 12.

FIG. 12(a) illustrates a state in which the liquid drop111of the alignment film material is discharged from the nozzle54of the head52. The diameter of the liquid drop111of the alignment film material at the moment the liquid drop111of the alignment film material is discharged from the nozzle54is 30 to 40 μm.

FIG. 12(b) illustrates a state in which the liquid drop111of an alignment film material discharged from the nozzle54is placed on the base member1(the point of time when the liquid drop111of an alignment film material first contacts the base member1). The diameter of the liquid drop111of the alignment film material at the moment the liquid drop111of an alignment film material is placed on the base member1is 30 to 40 μm, which does not change from the diameter of the liquid crystal drop111when the liquid drop111of the alignment film material is discharged from the nozzle54as illustrated inFIG. 12(a).

FIG. 12(c) illustrates a state in which the liquid drop111of the alignment film material is dropped onto the base member1and spreads. The diameter of the liquid drops111spreading on the base member1is about 100 μm.

As illustrated inFIGS. 12(b) and (a), the liquid drop111with the diameter (30 to 40 μm) that does not change from the diameter of the liquid drops111discharged from the head52collides with the base member1at the moment of placing the liquid drop111on the base member1. Then, as illustrated inFIG. 12(c), the liquid drop111spreads in a moment. The diameter of the liquid drops111illustrated inFIG. 12(a) at the moment the liquid drop111is discharged is 30 to 40 μm. As illustrated inFIG. 12(b), at the moment of placing the liquid drop111on the base member1, the liquid drop111of the above-mentioned size collides with the base member1and spreads (FIG. 12(c)).

The reference sign a ofFIG. 13denotes a part of the liquid drop111at the moment of being placed on the base member1, which is illustrated inFIG. 12(b) and whose diameter is about 30 to 40 μm. The reference sign b ofFIG. 13denotes the portion of the spreading liquid drop111illustrated inFIG. 12(c), whose diameter is about 100 μm.

As illustrated inFIG. 5(c), it is possible to variably set the pitch P′ of the nozzles by rotating the liquid drop discharge head52according to the present embodiment around the rotation shaft A. The experiment of checking the generation of the lines or spots154when the pitch between the nozzles54is changed to a plurality of values, which will be described next, can be realized due to the structure ofFIG. 5(c).

That is, the present inventor performed an experiment of setting the pitch P′ between the nozzles54as a plurality of values and checked the amount of lines or spots154. As a result, the following result is obtained. As illustrated inFIG. 14, in the case where the alignment film material is drawn by the inkjet method, when the nozzle pitch or the discharge distance (the pitch in the main scanning direction) is adjusted to the diameter (about 100 μm according to the above example and the reference sign b ofFIG. 13) of the liquid drop spreading after being placed, the spot is not generated in the portion where the liquid drops are placed (the portion of 30 to 40 μm according to the above example and the reference sign a ofFIG. 13), however, is generated in the portion where the liquid drop spreads (the portion in which the liquid drop spreads to thus move until the liquid drops are connected to the adjacent liquid drop and the reference sign b ofFIG. 13). The result corresponds to the above-mentioned state ofFIG. 25.

Therefore, as illustrated inFIG. 15, when the alignment film material is drawn by the inkjet method, the discharge distance (when the head has a plurality of nozzles, the nozzle pitch) in the sub-scanning direction (orthogonal to the main scanning direction) and the discharge distance in the main scanning direction are made equal to or less than the diameter of the liquid drops (30 to 40 μm according to the above example and the reference sign a ofFIGS. 15 and 13) immediately before (immediately after) being placed before spreading so that the liquid drop111of the alignment film material is not arranged (placed or dropped) on the base member1to exceed the distance. That is, instead of adjusting the pitch in the sub-scanning direction and the pitch in the main scanning direction to the diameter (the reference sign b ofFIGS. 13 and 14) at the moment the liquid drops are placed, the pitch in the sub-scanning direction and the pitch in the main scanning direction to the diameter are made equal to or less than the diameter of the liquid drops (the reference sign a ofFIGS. 13 and 15) immediately before the liquid drops are placed and the liquid drops111of the alignment film material are arranged on the base member1.

Also, inFIG. 14, only the problems of the nozzle pitches are described and the problems of the pitch in the main scanning direction are not described. However, the problems of the pitch in the main scanning direction are the same as the problems of the nozzle pitch. That is, as illustrated inFIG. 14, when the nozzle pitch is too wide, the lines or spots that extend to the main scanning direction are generated (refer toFIG. 25) in the regions that exceed the diameter of the liquid drops (the reference sign a ofFIGS. 14 and 13) immediately before the liquid drops are placed as denoted by the reference numeral91. When the pitch in the main scanning direction is too wide, the lines or spots that extend to the sub-scanning direction are generated (when both pitches are too wide, the lines or spots are generated in both directions).

FIG. 15illustrates a state in which the nozzle pitch and the pitch in the main scanning direction are adjusted to be equal to or less than the diameter of the liquid drops (the reference sign a ofFIGS. 15 and 13) immediately before the liquid drops are placed. InFIG. 15, since the liquid drops before spreading are connected to each other, it is possible to prevent the generation of the lines or spots.

FIG. 15illustrates a state in which the nozzle pitch and the pitch in the main scanning direction are set to be smaller than the diameter of the liquid drops (the reference sign a ofFIGS. 15 and 13) immediately before the liquid drops are placed. However, the respective pitches need not be smaller than the diameter of the liquid drops immediately before the liquid drops are placed. InFIG. 15, the adjacent liquid drops (the reference sign a ofFIGS. 15 and 13) overlap each other. However, the adjacent liquid drops need not overlap each other. As illustrated inFIG. 16, in order to connect the liquid drops (the reference sign a ofFIGS. 15 and 13) to each other to thus form the single thin film, the adjacent liquid drops (the reference sign a ofFIGS. 15 and 13) only have to contact each other.

As illustrated inFIG. 16, when the plurality of nozzles54are formed in the head52, the pitch Py between the nozzles54is the distance equal to or less than the diameter of the liquid drops (the reference sign a ofFIG. 13) immediately before (immediately after) the liquid drops are placed before spreading. Also, in the drawing direction (the main scanning direction: refer to the arrow Yc ofFIG. 10), the distance (the pitch) Px by which the liquid drops are discharged is the distance equal to or less than the diameter of the liquid drops (the reference sign a ofFIG. 13) immediately before (immediately after) the liquid drops are placed before spreading.

When the drawing is performed by the method illustrated inFIGS. 16 and 15, since a liquid drop before spreading overlaps another adjacent liquid drop before spreading, the drops are not generated. As mentioned above, when the liquid drops111are arranged (is dropped onto the base member1) during the drawing, the distance between the adjacent liquid drops111in the main scanning direction and the distance between the adjacent liquid drops111in the sub-scanning direction are equal to or less than the diameter of the liquid drops before spreading.

According to the present modification, unlike inFIGS. 15 and 16, even liquid drops (the reference sign a ofFIG. 13) in the main scanning direction immediately before (immediately after, hereinafter, only immediately before) being placed before spreading are dropped so as to deviate from the right position to the sub-scanning direction by half the diameter of an odd liquid drop (the reference sign a ofFIG. 13) immediately before being placed before spreading.

FIG. 18illustrates an arrangement in which the applying centers of the liquid drops inFIG. 17approach each other. InFIG. 15, the regions surrounded by four arcs, which are denoted by the reference numeral92are not the liquid drops (the reference sign a ofFIGS. 13 and 15) but the portions spreading from the liquid drops. Therefore, the portions92may become spots though this is only a slight possibility. On the other hand, inFIG. 18, an arbitrary liquid drop (the reference sign a ofFIGS. 13 and 17) overlaps another adjacent liquid drop (the reference sign a ofFIGS. 13 and 17) over the external circumference. Therefore, spots are not generated.

There are two methods of realizing the above. First, when a plurality of liquid drops (the reference sign a ofFIG. 13) are drawn, as illustrated in the arrow Ye ofFIG. 17, compared with the case where the odd liquid drops (the reference sign a ofFIG. 13) are drawn, the liquid drops are drawn by deviating the head52from the right position by half the diameter of the liquid drops (the reference sign a ofFIG. 13) to the sub-scanning direction with respect to the base member1.

Second, as illustrated inFIG. 19, a head group52aobtained by fixing a pair of (a plurality of) heads52to each other so that one head52deviates from the other by half the diameter of the liquid drops (the reference sign a ofFIG. 13) to the sub-scanning direction is scanned (mainly scanned) to the base member1. When the odd liquid drops (the reference sign a ofFIG. 13) are drawn, the liquid drops are discharged from the nozzles54of the first head52in the head group52a. When the even liquid drops (the reference sign a ofFIG. 13) are drawn, the liquid drops are discharged from the nozzles54of the second head52in the head group52a.

As mentioned above, according to the present embodiment, the liquid drops111are discharged so that a liquid drop111immediately after being placed (dropped) on the base member1before spreading is dropped so as to contact another adjacent liquid drop111in the same state (immediately after being placed before spreading).

Next, the method of discharging the liquid drops of the alignment film material by the inkjet method according to the present embodiment will now be described. The following method of applying the alignment film can be applied to the method of applying liquid drops other than the inkjet method.

Here, it is possible to prevent the generation of the spots of liquid drops of the alignment film. The spots are row changing lines generated on the boundary of the film drawn by the main scanning performed before and after performing the sub-scanning.

As a result of determining the cause of the above problem, it is noted that, in the portion drawn by performing main scanning once, an interface between the alignment film material (the liquid) and the air is generated on the substrate and that the portion becomes the spot of the alignment film material (the liquid).

Therefore, the drawing of all of the coated range of one unit (the coated area, for example, a single chip) is completed by performing the main scanning only once.

As mentioned above, when the region that cannot be drawn by performing first main scanning since the region exceeds the range in which the nozzles of the inkjet head are formed among the range to be coated with the alignment film material (the liquid) is drawn by performing second main scanning, the spots of the liquid crystal (the liquid) are generated. This will be described with reference to the following drawings.

FIG. 20illustrates a case in which a plurality of chips102is formed on a wafer101. Each of the plurality of chips102constitutes a liquid crystal panel of, for example, a mobile telephone. The liquid drops of the alignment film material are simultaneously discharged to the plurality of chips102using the plurality of nozzles54formed in the liquid drop discharge head52.

In this case, in order to improve the productivity, it is preferable that the liquid drops of the alignment film material be applied to the chips102as many as possible on the wafer101using all of the nozzles54of the liquid drop discharge head52from one end to the other end to the direction where the liquid drop discharge head52extends by performing the main scanning (in the direction X) once.

InFIG. 20, the chips102are arranged in the order of the reference numerals102a,102b,102c, . . . , and102zfrom the left end of the wafer101. In this case, as illustrated inFIG. 20, when the nozzle54of one end of the liquid drop discharge head52is adjusted to the position of the chip102ain which the liquid drops are arranged, the nozzle54in the other end of the liquid drop discharge head52is positioned in the middle of the chip102c.

In order to improve the productivity, it is preferable that all of the nozzles54be used in the arrangement state of the liquid drop discharge head52illustrated inFIG. 20. That is, it is preferable that the entire regions of the chips102aand102band the region to the middle of the chip102cbe coated with the liquid drops by performing the first main scanning and that the remaining half of the chip102cand the chips after the chip102dincluding the chip102dbe coated with the liquid drops by performing the second main scanning. As mentioned above, it is possible to reduce the number of performances of the main scanning required for coating the plurality of chips102on the wafer101by using all of the nozzles54from one end to the other end in the longitudinal direction of the liquid drop discharge head52. According to the method, it is possible to improve the productivity. Therefore, the method is commonly used.

However, according to the above method, as illustrated inFIG. 21, the liquid drops of the alignment film material are applied to one chip102cby performing the second main scanning. Therefore, in the area (the coated area) to be coated with the alignment film material in the chip102c, an interface105between the liquid crystal and the air is generated in the end of the region coated with the liquid crystal by performing the first main scanning. Then, the interface105is coated with the liquid drops of the alignment film material by performing the second main scanning. However, the spot is generated in the interface105.

Here, the coated area is a region to be coated with the alignment film material (the liquid), in which it is desired to avoid the generation of coating spots, in maximum units in terms of an area (each of the chips102ato102zaccording to the present example). That is, the coated area is the region, whose entire surface should be uniformly coated, in the maximum units in terms of an area (a chip according to the present example, however, a substrate when a single substrate is formed of one wafer). The coated area is commonly a display area in a single panel.

Therefore, according to the present embodiment, as illustrated inFIGS. 21 and 22, when there exists a coated area (according to the present example, the chip102c) that cannot be coated by performing the main scanning once among the plurality of coated areas (according to the present example the chips102ato102z), the coated area (according to the present example, the chip102c) is not coated with the liquid drops of the alignment film material by performing the main scanning of the time in order to prevent the generation of the spot.

That is, as illustrated inFIG. 22, when the main scanning of the liquid drop discharge head52is performed in a state where the liquid drop discharge head52covers only the chip102conly to the middle of the chip102c, the entire region of the chip102ccannot be coated by performing the main scanning once. When the main scanning is performed in such a state, the nozzle denoted by the reference numeral54babove the chip102cis controlled not to discharge the liquid drops of the alignment film material. It is possible to prevent the generation of the interface between the alignment film material and the air on the chip102cby controlling the nozzle54bnot to discharge the liquid drops of the alignment film material and to thus prevent the generation of the coating spots.

In general, in view of the productivity, it is tried to reduce the number of performances of the main scanning by discharging the liquid drops of the alignment film material from the nozzle above the chip. However, according to the present embodiment, the quality (it is possible to prevent the generation of coating spots of the alignment film material) is the first priority even at the expense of productivity.

As mentioned above, the chips102aand102bare coated with the liquid drops of the alignment film material by performing the first main scanning. Also, the liquid drops are not discharged from the nozzle denoted by the reference numeral54aby performing the main scanning in the position of the drawing (like in the conventional art). This is because the nozzle denoted by the reference numeral54ais positioned above the area to which the liquid drops of the alignment film material are not to be discharged (in which chips do not exist).

Next, the liquid drop discharge head52performs the sub-scanning from the position illustrated inFIG. 22in the direction of the arrow Y. As a result, as illustrated inFIG. 23, when the liquid drop discharge head52reaches the position in which the liquid drops of the alignment film material discharged from the liquid drop discharge head52can coat all of the regions of the chip102cthat are not coated in a previous time (by performing the first main scanning) by performing the second main scanning, the chip102cis coated with the liquid drops of the alignment film material by performing the second main scanning.

In the second main scanning, like in the first main scanning, among the plurality of coated areas (according to the present example, the chips102ato102z), when there exists a coated area (according to the present example, the chip102e) in which all of the regions cannot be coated by performing the main scanning once, the coated area (according to the present example, the chip102e) is not coated with the liquid drops of the alignment film material by performing the main scanning. Then, third main scanning is performed.

According to the above example, during the main scanning of the respective times, when the liquid drops of the alignment film material are discharged to two columns of chips102(to the chips102aand102bin the first main scanning and to the chips102cand102din the second main scanning), the liquid drops of the alignment film material are not discharged from the nozzles54corresponding to the positions of the chips102of the third column (to the chip102cin the first main scanning and to the chip102ein the second main scanning). When the objects to be coated with the liquid drops of the alignment film material are difference from those on the wafer101ofFIG. 20, that is, when the size or the arrangement of the chips on the wafer is difference from that ofFIG. 20, to how many columns of chips the liquid drops of the alignment film material are discharged and from which nozzle54corresponding to the position of chip that belongs to which column the liquid drops of the alignment film material are not discharged varies with the main scanning of each time. Here, for example; from the following equation, it is possible to obtain the number of columns of the chips from which the liquid drops of the alignment film material are to be discharged during the main scanning each time.

The maximum value of n that satisfies n×d1+(n−1)×d2≦L is obtained.

As illustrated inFIG. 20, d1denotes the width of each chip102(the length of the side of the chip102along the direction to which the liquid drop discharge head52extends, specifically, the width of the region in which a liquid crystal film is to be formed in the chip102). d2denotes the distance between the chips102(specifically, the distance between the regions in which the liquid crystal films are to be formed in the adjacent chips102). L denotes the length of the liquid drop discharge head52(more specifically, the length between the nozzle54of one end in the direction where the liquid drop discharge head52extends and the nozzle54of the other end) to the direction in which the liquid drop discharge head52extends.

During the first main scanning, the chips to the nth column are coated with the liquid drops of the alignment film material and the liquid drops of the alignment film material are not discharged from the nozzle54corresponding to the position of the,(n+1)th column.

During the second main scanning, on the based of the (n+1)th column, the chips to the nth column (n+1−1+n) are coated with the liquid drops of the alignment film material and the liquid drops of the alignment film material are not discharged from the nozzle54corresponding to the position of the chip of the (n+1−1+n+1)th column.

In the example ofFIG. 20, the maximum value of n is 2 so that the following equations are established.
2×d1+(2−1)×d2≦L
3×d1+(3−1)×d2>L

During the first main scanning, the chips to the second column (102aand102b) are coated with the liquid drops of the alignment film material and the liquid drops of the alignment film material are not discharged from the nozzle54corresponding to the position of the chip (102c) of the (2+1=3)rd column.

During the second man scanning, the chips (102cand102d) of two columns (2+1−1+2=4) based on the (2+1=3)rd column are coated with the liquid drops of the alignment film material and the liquid drops of the alignment film material are discharged from the nozzle54corresponding to the position of the chip (102e) of the (2+1−1+2+1=5)th column.

As mentioned above, the main scanning of each time when the chips102of a plurality of columns are coated with the liquid drops of the alignment film material is performed on the chips of the columns of the maximum value of n that satisfies n×d1+(n−1)×d2≦L. Therefore, it is possible to prevent a certain chip102from being coated with the alignment film material by performing a plurality of times of main scanning. Also, an operator can pre-input the n value to a program and the liquid drop discharge head52can coat the chips with the liquid drops of the alignment film material in accordance with the input n value.

That is, when the main scanning is performed once, no matter what chip (coated area)102is selected, it is not possible that both of coated regions and non-coated regions exist in the single chip102. No matter what chip102is selected, all of the coated areas in the single chip102are coated with the alignment film material by performing the main scanning once. As mentioned above, since all of the regions of the single coated area are coated with the alignment film material by performing the main scanning once, no interface is generated between the alignment film material (the liquid) and the air on the single coated area. Therefore, no spots are generated in joints of scanning in display regions.

Also, as illustrated inFIG. 15, in the liquid drop discharge head52ofFIG. 20, the pitch between the nozzles54is determined by overlapping one liquid drop of the alignment film material before spreading with another adjacent liquid drop before spreading on each chip102. So is the discharge distance in the main scanning direction.

Instead of the above, as illustrated inFIG. 18, in the liquid drop discharge head52inFIG. 20, the pitch between the nozzles54is determined by overlapping one liquid drop of the alignment film material before spreading with another adjacent liquid crystal drop before spreading. So is the discharge distance in the main scanning direction on each chip102. In this case, as illustrated inFIG. 18, an arbitrary liquid drop of the alignment film material (the reference sign a ofFIGS. 13 and 17) overlaps another liquid drop of the alignment film material (the reference sign a ofFIGS. 13 and 17) over the external circumference.

FIG. 24illustrates a modification of the present embodiment.

InFIG. 20, the length L of the liquid drop discharge head52is larger than the width d1of the single coated area. All of the regions of at least one coated area can be coated by performing the main scanning once. Therefore, inFIG. 24, a single substrate202is formed on a single wafer201. In the case ofFIG. 24, the coated area (a substrate202) is larger than the coated area (the chip102) of the case ofFIG. 20. In order to coat all of the regions of the coated area by performing the main scanning once, it is necessary to form nozzles54in the range equal to the width d1′ of the substrate202.

When the length of the single liquid drop discharge head52is smaller than the width d1′ of the substrate202, the nozzles54are located in the range equal to the width d1′ by connecting the plurality of liquid drop discharge heads52A and52B to each other. As illustrated inFIG. 20, even when the length. of the single liquid drop discharge head52is larger than the width d1of the chip of the coated area (the chip102), in order to coat a wider range of coated area by performing the main scanning once, the plurality of liquid drop discharge heads52can be connected to each other.

In this case, the pitches {circle around (1)} and {circle around (3)} between the nozzles54of the plurality of liquid drop discharge heads52A and52B connected to each other are equal in accordance with defined pitches (refer toFIGS. 15 and 18).

The nozzle pitch {circle around (2)} in the connecting portion between the plurality of liquid drop discharge heads52A and52B is set to be equal to the defined nozzle pitch {circle around (1)}. For example, {circle around (1)}={circle around (2)}={circle around (3)}=30 to 40 μm.

As mentioned above, according to the present embodiment, it is possible to obtain the following effects.

When the inkjet head performs a plurality of times of scanning to thus drop the alignment film material onto a display area, interfaces between the alignment film material and the air are generated in the display area by the number of performances of scanning and the portions become drawing spots. However, according to the present embodiment, since the alignment film material is dropped to all of the regions in the display range of a panel by performing drawing (scanning) once, it is possible to remove the interfaces between the alignment film material and the air in the display area and to thus prevent the generation of the spots due to the application of the alignment film material.

Also, when the drawing range is wide, the plurality of heads is bonded to each other to constitute one head. Therefore, it is possible to omit row changing works during the drawing and to thus remove the spots in the row changing portions.

Next, as illustrated inFIG. 3(g), a sealing material32is formed on the alignment film16by screen printing. Here, UV-hardening resin is used as the sealing material32(step S107).

When the formation of the sealing material is completed, as illustrated inFIG. 3(h), the alignment film16is coated with liquid crystal33by discharging the liquid drops (step S108). Here, a spacer material that forms the spacers13is mixed in the liquid crystal33discharged as the liquid crystal drops.

The method of discharging the liquid drops of the liquid crystal33is the inkjet method. The method of applying and arranging the liquid crystal drops may be the same as the aforementioned methods of applying an alignment film. Also, instead of the aforementioned methods of applying and arranging the alignment film, a method of discharging and arranging the well-known liquid crystal drops by the inkjet method may be adopted.

When coating with the liquid crystal drops is completed and a single thin film is formed as illustrated inFIGS. 11 and 3(i), the process proceeds to the next step. That is, through a process of attaching the color filter substrate10acoated with the liquid crystal to the counter substrate10b(step S109), an electro-optical panel100is completed.

Next, as illustrated inFIG. 3(j), a harness, an FC (flexible cable) substrate7, and a driver IC5are mounted on the completed electro-optical panel100(step S110). As illustrated inFIG. 3(k), the electro-optical panel100is attached to an electronic apparatus9such as a mobile telephone or a personal digital assistant (PDA) to thus complete the electronic apparatus (step S111).

According to the present embodiment, the application-position by the inkjet method is described with respect to the liquid drops of the alignment film. However, when the target to be discharged is liquid crystal drop, the dropping position becomes more important. This is because the lines or spots generated when the liquid crystal is dropped on the alignment film particularly matter. The liquid crystal matters since there exists the interaction between the liquid crystal and the materials of the alignment film (for example, 3% of polyimide and 97% of a solvent and the liquid crystal drops without including a solvent are dropped.

However, the present invention in relation to the application position by the inkjet method is not restricted to the liquid crystal drops. That is, the present invention can be widely applied to liquid drops discharged by the inkjet discharging method. There are various liquid drops discharged by the inkjet discharging method including a liquid drop for forming a beta film uniformly coated all of the substrate such as a photoresist film (about 1 μm), an overcoat film (equal to or less than 10 μm), and the alignment film required for manufacturing the electro-optical panel (a liquid crystal display device or an organic EL panel) and a liquid drop for forming a film that constitutes a layer in each pixel such as a color filter and an organic EL material (light emitting material ink: after baked, several tens of nanometers). Also, the inkjet discharging method can be widely applied to industries such as liquid drops that constitute a liquid film such as a photoresist film required for other fields than the manufacturing of the electro-optical panel. The present invention can be widely applied to these liquid drops.

Objects to which the present invention can be applied

Electronic apparatuses to which the electro-optical panel according to the present invention can be applied include apparatuses using the electro-optical panels that are electro-optical devices such as a mobile telephone, a personal information apparatus or a portable personal computer referred to as PDAs, a personal computer, a digital camera, a vehicle-mounted monitor, a digital video camera, a liquid crystal TV, view finder type and monitor direct view type video tape recorders, a car navigation device, a pager, an electronic organizer, a calculator, a word processor, a workstation, a picture telephone, and a POS terminal.

Therefore, the present invention can be applied to electrical connection structures in these electronic apparatuses.

Also, the electro-optical panel is a transmissive or reflective electro-optical panel, in which an illuminating device is used as a backlight (not shown). Also, the same is true of a color electro-optical panel in an active matrix. For example, according to the above-mentioned embodiments, electro-optical panels in a passive matrix are illustrated. However, the electro-optical panel in the active matrix (for example, an electro-optical panel including a thin film transistor (TFT). or a thin film diode (TFD) as a switching element) can be used as the electro-optical device according to the present invention. Also, it is possible to apply the present invention to various electro-optical devices in which display states of a plurality of pixels can be respectively controlled such as an electroluminescent (EL) device, an inorganic electroluminescent (EL) device, a plasma display device, an electrophoresis display device, a field emission display device, and a light emitting diode (LED) as well as the transmissive or reflective electro-optical panel.