Droplet ejecting apparatus, method of forming a thin film, and substrate for a display device

A droplet ejecting apparatus, method of forming a thin film, and a substrate for a display device, wherein a droplet ejecting apparatus includes a first ejecting unit ejecting a first droplet on a substrate, a second ejecting unit ejecting a second droplet on the substrate along a path defined by a movement of the first ejecting unit, and a transporting unit connected with the first ejecting unit and the second ejecting unit to transport the first ejecting unit and the second ejecting unit.

CROSS-REFERENCE OF RELATED APPLICATION

The present application claims priority from Korean Patent Application No. 2005-11285, filed on Feb. 2, 2005, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a droplet ejecting apparatus, a method of dropping a droplet, a method of forming a thin film pattern, and a substrate for a display device. More particularly, the present invention relates to a droplet ejecting apparatus that improves an image display quality, a method of dropping a droplet, and a method of forming a thin film pattern, and a substrate for a display device.

2. Description of the Related Art

A display device is an interface device converting data that is processed by an information processing device into an image.

The display device includes a flat panel display device, such as a liquid crystal display device (LCD), an organic light emitting display device (OLED), a plasma display panel (PDP), or the like.

The flat panel display devices have thin film patterns, which include thin film transistors (TFTs), gate lines, data lines, pixel electrode, black matrix, color filter, common electrode, etc.

The thin film patterns are formed through complex and time-consuming processes, such as a deposition process, a photolithography process, an etching process, a rinsing process, etc. Therefore, a more efficient fabrication process is needed to form the thin film patterns.

SUMMARY OF THE INVENTION

The present invention provides a droplet ejecting apparatus that improves an image display quality of a display device. Additional features of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention.

The present invention discloses a droplet ejecting apparatus, including a first ejecting unit ejecting a first droplet on a substrate, a second ejecting unit ejecting a second droplet on the substrate along a path defined by a movement of the first ejecting unit, and a transporting unit connected with the first ejecting unit and the second ejecting unit to transport the first ejecting unit and the second ejecting unit.

The present invention also discloses a method of dropping a droplet on a substrate, including disposing first droplets on the substrate along a path, and disposing second droplets in a path region of the substrate that is adjacent to the path, wherein each of the second droplets is disposed between the first droplets.

The present invention also discloses a method of forming a thin film pattern on a substrate including disposing first droplets on a portion of recesses that are arranged substantially parallel with one another on the substrate, disposing second droplets on another portion of the recesses, and drying the first droplets and the second droplets to form thin film patterns, wherein each of the second droplets is disposed between the first droplets.

The present invention also discloses a method of forming a thin film pattern on a substrate, including disposing a first droplet on each of a plurality of recesses that arranged substantially parallel with one another on the substrate, disposing a second droplet on each of the recesses, and drying the first and second droplets to form thin film patterns on the recesses of the substrate.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

It should be understood that the exemplary embodiments of the present invention described below may be varied modified without departing from the inventive principles disclosed herein, and the scope of the invention is therefore not limited to the following embodiments. Rather, the embodiments are provided to fully disclose and convey the concept of the invention to those skilled in the art by way of example and not of limitation.

Hereinafter, the present invention is described with reference to the accompanying drawings.

FIG. 1is a plan view showing a droplet ejecting apparatus according to an embodiment of the invention.FIG. 2is a cross-sectional view taken along a line I-I′ shown inFIG. 1.

Referring toFIG. 1andFIG. 2, the droplet ejecting apparatus100includes a first ejecting unit110, a second ejecting unit120, and a transporting unit130. The first ejecting unit110ejects first droplets111on a substrate140. The second ejecting unit120ejects second droplets121on the substrate140.

The transporting unit130transports the first ejecting unit110and the second ejecting unit120, which are each connected with the transporting unit130.

The first ejecting unit110is substantially parallel with the second ejecting unit120. The transporting unit130pivots with the first ejecting unit110and the second ejecting unit120and rotates the fist and second ejecting units110and120with respect to a first pivot116between the transporting unit130and the first ejecting unit110, and a second pivot126between the transporting unit130and the second ejecting unit120. According to the embodiment of the invention shown inFIG. 2, rotational angles of the first and second ejecting units110and120are substantially the same.

The first ejecting unit110includes a first ejecting body113and a first actuator114.

The first ejecting body113may have a rectangular plate shape, as shown inFIG. 2; however, the shape is not limited thereto. A plurality of first nozzles112are formed on the first ejecting body113. For example, each of the first nozzles112includes a through hole formed on the first ejecting body113. The first nozzles112adjacent to each other are spaced apart from each other by a first distance W1, as shown inFIG. 1.

The first actuator114ejects liquids on the substrate140through the first nozzles112of the first ejecting body113. The first actuator114includes a first conduit115for the first actuator114to receive liquid.

The second ejecting unit120includes a second ejecting body123and a second actuator124.

The second ejecting body123may have a rectangular plate shape, as shown inFIG. 2; however, the shape is not limited thereto. A plurality of second nozzles122are formed on the second ejecting body123. For example, each of the second nozzles122includes a through hole formed on the second ejecting body123. The second nozzles122adjacent to each other are spaced apart from each other by a second distance W2. The second distance W2may be substantially equal to the first distance W1; however, the invention is not limited thereto.

The second actuator124ejects liquids on the substrate140through the second nozzles122of the second ejecting body123. The second actuator124includes a second conduit125for second actuator124to receive liquid.

The position of the first nozzles112corresponds with the position of the second nozzles122. Each of the first nozzles112is spaced apart from each of the second nozzles122by a first distance D1.

FIG. 3is a plan view showing a first ejecting unit and a second ejecting unit according to an embodiment of the invention.FIGS. 4A,4B, and4C are plan views showing first droplets112and second droplets121formed by the first etching unit and the second ejecting unit, respectively, shown inFIG. 3.

Referring toFIG. 3, the second nozzles of the second ejecting body123are aligned with the first nozzles112of the first ejecting body113. For example, as shown inFIG. 3, each of the second nozzles122is provided along a path P defined by each of the first nozzles112, or vice-versa. The path P is a trace of each of the first nozzles112transported by the transporting unit130.

When each of the second nozzles122is located along the path that is defined by each of the first nozzles112, then each of the first droplets111and each of the second droplets121are located along the path P.

Referring toFIG. 2andFIG. 4A, the first droplets111ejected through each of the first nozzles112and the second droplets121ejected through each of the second nozzles122are provided along the path P. According to the embodiment of the invention discussed above and shown inFIG. 2andFIG. 4A, the first and second droplets111and121are alternately disposed along the path P.

Referring toFIG. 2andFIG. 4B, the first droplets111and the second droplets121are ejected through the first nozzles112and the second nozzles122, respectively, along the path P. For example, the first actuator114aligns the first droplets111ejected through each of the first nozzles112along the path P, and at least two of the first droplets ejected through each of the first nozzles112are adjacent to each other. The second actuator124aligns the second droplets121ejected through each of the second nozzles122along the path P, and at least two of the second droplets ejected through each of the second nozzles122are adjacent to each other. According to an embodiment of the invention, the number of the first droplets111adjacent to each other is substantially equal to the number of the second droplets121adjacent to each other. Further, the first droplets111adjacent to each other and the second droplets121adjacent to each other may be alternately disposed along the path P.

Referring toFIG. 2andFIG. 4C, the first droplets111and the second droplets121are randomly disposed on the path P. For example, the first actuator114may align the first droplets111on the path P. One of the first droplets111ejected may be disposed between the second droplets121ejected through each of the second nozzles122, or multiple first droplets111may be adjacent to each other.

The second actuator124aligns the second droplets121ejected through each of the second nozzles122on the path P. One of the second droplets121ejected through each of the second nozzles122may be between the first droplets111ejected through each of the first nozzles112, or multiple second droplets121may be adjacent to each other. The number of the first droplets111adjacent to each other may be different from the number of the second droplets is121adjacent to each other. At least one of the first droplets111adjacent to each other and at least one of the second droplets121adjacent to each other may be alternately disposed along the path P.

FIG. 5is a plan view showing a first ejecting unit and a second ejecting unit according to an embodiment of the invention.FIGS. 6A,6B and6C are plan views showing droplets formed by the first ejecting unit and the second ejecting unit ofFIG. 5.

Referring toFIG. 5, the second nozzles of the second ejecting body123are positioned with respect to a position of the first nozzles112of the first ejecting body113. For example, as shown inFIG. 5, each of the second nozzles122may be provided in a path region PR along a path P defined by each of the first nozzles112. For example, each of the second nozzles122may be provided along the path P or along a line that is substantially parallel with the path P. The path region PR may have a constant width; however, the path region is not limited to having such constant width.

When each of the second nozzles122is in the path region PR along the path P, each of the first droplets111ejected through each of the first nozzles112is disposed on the path P and each of the second droplets121ejected through each of the second nozzles122is disposed in the path region PR. For example, the first droplet may be disposed such that it is centered over the path P.

Referring toFIG. 5andFIG. 6A, the first droplets111are disposed on the path P, and the second droplets121are disposed in the path region PR. For example, the first actuator114aligns the first droplets111ejected through each of the first nozzles112on the path P, and the second actuator124aligns the second droplets121ejected through each of the second nozzles122on the line in the path region PR, which is substantially parallel with the path P. The first and second droplets111and121may be disposed in a variety of patterns, such as, for example, alternately disposed in the path region PR.

According to another embodiment of the invention, as shown inFIG. 6B, the first actuator114may align the first droplets111ejected through each of the first nozzles112on the path P such that at least two of the first droplets ejected are adjacent to each other. The second actuator124may align the second droplets121ejected through each of the second nozzles122on the line in the path region PR such that at least two of the second droplets are adjacent to each other. The number of the first droplets111adjacent to each other is substantially equal to that of the second droplets121adjacent to each other. Further, the first droplets111adjacent to each other and the second droplets121adjacent to each other may be alternately disposed in the path region PR.

According to another embodiment of the invention, as shown inFIG. 5andFIG. 6C, the first droplets111ejected through each of the first nozzles112and the second droplets121ejected through each of the second nozzles122are in the path region PR in a random order. For example, the first actuator114aligns the first droplets111on the path P. One of the first droplets111may be disposed between the second droplets121, or at least two of the first droplets121may be disposed adjacent to each other. The second actuator124aligns the second droplets121on the line in the path region PR, which is substantially parallel with the path P. One of the second droplets121may be disposed between the first droplets111, or at least two of the second droplets121are disposed adjacent to each other. The number of the first droplets111that are adjacent to each other may be different from the number of the second droplets121that are adjacent to each other. Further, at least one of the first droplets111adjacent to each other and at least one of the second droplets121adjacent to each other may be alternately disposed in the path region PR.

According to the embodiment of the invention shown inFIG. 5andFIG. 6C, the droplet ejecting apparatus may alternately eject the first droplets111and the second droplets121. Instead, the droplet ejecting apparatus may eject the first droplets111and the second droplets121in a random order.

FIG. 7AandFIG. 7Bare plan views showing a method of forming droplets according to an embodiment of the invention.

Referring toFIG. 7A, a path P and a path region PR adjacent to the path P are defined on a substrate300.

First droplets310are disposed, e.g., dropped, on the substrate300along the path P. The first droplets310adjacent to each other are spaced apart at a first distance W1from each other. The substrate300may include a plurality of paths.

The first droplets310may include a material for forming a color filter, a material for forming a positive charge injection layer, a material for forming a negative charge injection layer, a material for forming a light emitting layer, and the like.

When the first droplets310are dropped or disposed on the substrate300second droplets320are dropped or disposed on the substrate300after the first droplets310are dropped or disposed on the substrate300.

Referring toFIG. 7B, the second droplets320are disposed on the substrate300adjacent to the first droplets310. The second droplets320may be disposed along a line in the path region PR, which is substantially parallel with the path P. Alternatively, the second droplets320may be disposed along the path P.

The second droplets320may be disposed between the first droplets320such that the first droplets310and the second droplets320are alternately arranged in the path region PR.

Similar to the first droplets310, the second droplets320may include the material for forming the color filter, the material for forming the positive charge injection layer, the material for forming the negative charge injection layer, the material for forming the light emitting layer, and the like.

The first droplets310may be formed of substantially the same material as the second droplets320.

FIG. 8AandFIG. 8Bare plan views showing another method of forming droplets according to an embodiment of the invention. The method ofFIG. 8AandFIG. 8Bis the same as the method discussed above ifFIG. 7AandFIG. 7B, except the number of second droplets adjacent to each other and a line along which the second droplets are aligned. Thus, the same reference numerals are used to refer to the same or similar parts as those described in aboveFIGS. 7A and 7Band any further explanation is omitted, as necessary.

Referring toFIG. 8AandFIG. 8B, the second droplets320are disposed adjacent to first droplets310. For example, the second droplets320may be in a path region PR that is adjacent to a path P, which is defined by the first droplets310. As shown inFIG. 8AandFIG. 8B, the second droplets320are disposed on the path P.

The second droplets320may be disposed between two first droplets310disposed adjacent to each other. That is, an interval or space between the two first droplets310disposed adjacent to each other may be different from an interval or space between two second droplets320disposed adjacent to each other.

The first droplets310and the second droplets320may be disposed on the path P in a consistent order or a random order to make uniform a quality of the thin film patterns (hereinafter referred to as “thin films”) formed from the first droplets310and the second droplets320by drying the first droplets310and the second droplets320.

FIG. 9is a plan view showing first droplets formed on a substrate according to an embodiment of the present invention.FIG. 10is a cross-sectional view taken along a line II-II′ shown inFIG. 9. A droplet ejecting apparatus ofFIG. 9andFIG. 10is the same as is used inFIGS. 1,2and3. Thus, the same reference numerals are used to refer to the same or similar parts as those described inFIGS. 1,2, and3and any further explanation is omitted as necessary.

Referring toFIGS. 1,9and10, a plurality of recesses403are formed on a substrate400in a matrix or array shape. A black inorganic thin film may be patterned to form the recesses403may be formed by patterning a black inorganic thin film. Alternatively, the recesses403may be formed by patterning a photoresist film containing a black organic material.

A first ejecting unit110of the droplet ejecting apparatus100may be aligned along odd numbered columns of the recesses403. Accordingly, first nozzles112of the first ejecting unit110eject first droplets410on odd numbered recesses OR. In this exemplary embodiment, a volume of each of the first droplets410is no less than that of each of the recesses403. It is understood that the first ejecting unit110may instead be aligned along even numbered columns of the recesses403.

FIG. 11is a plan view showing second droplets formed on the substrate shown inFIG. 9.FIG. 12is a cross-sectional view taken along a line III-III′ shown inFIG. 11.

Referring toFIGS. 1,11and12, the droplet ejecting apparatus100ejects second droplets420on even numbered recesses ER of the odd numbered columns through second nozzles122of the second ejecting unit120. Therefore, both the first droplets410and the second droplets420are ejected on the recesses403of the odd numbered columns.

The first droplets410and the second droplets420are formed of substantially the same material.

The droplet ejecting apparatus100then ejects the first droplet410and the second droplets420on recesses403of even numbered columns so that the first and second droplets410and420are disposed on all of the entire of the recesses403.

FIG. 13is a cross-sectional view showing dried first and second droplets shown inFIG. 12.

Referring toFIGS. 1,12and13, the first droplets410in the odd numbered recesses OR of the recesses403are dried to form first thin films435, and the second droplets420in the odd numbered recesses OR of the recesses403are dried for a sufficient period of time and form second thin films430.

Each of the first and second thin films435and430may be a red color filter, a green color filter, or a blue color filter. Alternatively, each of the first thin films435and the second thin films430may be a positive charge carrier injecting layer, a negative charge carrier injecting layer, a light emitting layer, and the like.

The first droplets410that form the first thin films435may have different volumes from one another. A thickness of the first thin films435and the second thin films430charges according to the volume of the first droplets410and the second droplets, respectively.

The first thin film435and the second thin films430, which may have different thicknesses, are aligned in either a consistent order or in a random order so that lights generated from the first thin film435and the second thin films430are combined, thereby improving an image display quality of the display device.

FIG. 14is a plan view showing first droplets formed on a substrate in according is to another embodiment of the invention. A droplet ejecting apparatus ofFIG. 14is the same as the droplet ejecting apparatus used inFIGS. 1,2and3. Thus, the same reference numerals are used to refer to the same or similar parts as those described inFIGS. 1,2and3and any further explanation is omitted, as necessary.

Referring toFIGS. 1 and 14, a plurality of recesses403are arranged on a substrate400in a matrix or array shape. The recesses403may be formed by patterning, black inorganic thin film. Alternatively, the recesses403may be formed by patterning black organic material having photoresist.

A first ejecting unit110of the droplet ejecting apparatus100is aligned along recesses403on odd numbered columns. First nozzles112of the first ejecting unit110eject a first droplet410on the recesses403of the odd numbered columns. The number of the first droplets410disposed on each of the recesses403of the odd numbered columns may be random. Alternatively, the number of the first droplets410disposed on each of the recesses403of the odd numbered columns may be constant or a predetermined amount.

FIG. 15is a plan view showing second droplets disposed on the substrate shown inFIG. 14.

Referring toFIGS. 1 and 15, the droplet ejecting apparatus100ejects second droplets420on the recesses403of the odd numbered columns through second nozzles122of the second ejecting unit120. The second droplets420may be adjacent to the first droplets420, and the second droplets420may also be disposed between the first droplets420adjacent to each other. Therefore, the first droplets410and the second droplets420are ejected on each of the recesses403of the odd numbered columns.

The first droplets410and the second droplets420are formed of substantially the same material.

The droplet ejecting apparatus100then ejects the first droplets410and the second droplets420on the recesses403of even numbered columns so that the first droplets410and the second droplets420are disposed on all of the recesses403.

The first droplets410and the second droplets420disposed in the recesses403are dried for a sufficient period of time to form thin films430.

The thin films430may be a red color filter, a green color filter, or a blue color filter. Alternatively, each of the thin films430may be a positive charge carrier injecting layer, a negative charge carrier injecting layer, a light emitting layer, and the like.

The first droplets410that form the first thin films435may have different volumes from one another. Likewise, the second droplets420that form the second thin films of430may have different volumes from one another. A thickness of the first thin films435and the second thin films430charges according to the volume of the first droplets410and the second droplets, respectively. The first droplets410and the second droplets420are combined on each of the recesses403so that the thin films430may have a constant thickness, e.g., level.

FIG. 16is a cross-sectional view showing a substrate for a display device according to an embodiment of the invention.

Referring toFIG. 16, the substrate500may be a color filter substrate for a liquid crystal display (LCD) device.

The substrate500includes a transparent plate510, first pixel thin films520and second pixel thin films530. The substrate500may further include an over-coating layer540and a common electrode550.

A plurality of pixel regions are defined on the transparent plate510by a black matrix505, which is provided on the transparent plate510. A peripheral region surrounding the pixel regions may also be defined on the transparent plate510.

A thin film, such as an oxide chromium thin film, a chromium thin film, a black organic layer, and the like, is patterned to form the black matrix505.

The first pixel thin films520have a first thickness and are provided on odd numbered pixel regions of odd numbered columns. The second pixel thin films530have a second thickness provided on even numbered pixel regions of the odd numbered columns. The second thickness may be different from the first thickness. For example, in the embodiment shown inFIG. 16, the first thickness is greater than the second thickness.

The first pixel thin films520and second pixel thin films530may each be a red color filter, a green color filter, or a blue color filter.

The first pixel thin films520and the second pixel thin films530may each be thinner than the black matrix505. When each of the first pixel thin films520and the second pixel thin films530is thinner than the black matrix505, the over-coating layer540is formed on the transparent plate510to planarize an upper surface of the transparent plate510pixel.

The common electrode550may be on the over-coating layer540. The common electrode550may include a transparent conductive material such as indium zinc oxide (IZO), indium tin oxide (ITO), amorphous indium tin oxide (a-ITO), and the like.

FIG. 17is a cross-sectional view showing a substrate for a display device according to another embodiment of the invention.

Referring toFIG. 17, the substrate600includes a transparent plate610, first electrodes620, an organic pattern605having recesses605a, first pixel thin films630, second pixel thin films640and a second electrode650coupled with the pixel thin films630. The first pixel thin film630and the second pixel thin film640contact the first electrodes620

Each of the first electrodes620formed on the transparent plate610includes a transparent conductive material, such as IZO, ITO, etc. The first electrodes620are arranged on the transparent plate610in a matrix or array shape.

The organic pattern605or an inorganic pattern (not shown) is provided on the transparent plate610. The organic pattern605includes the recesses605athrough which the first electrodes620are exposed. The recesses605aare arranged on the transparent plate610in a matrix or array shape.

The first pixel thin films630having a first thickness are provided on odd numbered recesses605aof odd numbered columns. The second pixel thin films640having a second thickness are provided on even numbered recesses605aof the odd numbered columns. The second thickness may be different from the first thickness. For example, the first thickness may be thinner than the second thickness.

According to the embodiment of the invention shown inFIG. 17, each of the first and second pixel thin films630and640may include a positive charge carrier injecting layer, a light emitting layer, a negative charge carrier injecting layer, etc. The light emitting layer may be positioned between the positive charge carrier injecting layer and the negative charge carrier injecting layer.

The second electrode650is provided on the transparent plate610having the first electrodes620, the organic pattern605, the first pixel thin film630, and the second pixel thin film640. The second electrode650is coupled with the first pixel thin film630and the second pixel thin films640.

According to an embodiment of the invention, droplets from different nozzles are is formed in each of the columns to improve the image display quality of the display device.