KR101596059B1 - Fluid dispensing method - Google Patents

Abstract

To a method of providing a first fluid on a surface for manufacturing an electrowetting device of the present invention. The method includes providing a surface; Providing an amount of a second fluid incapable of mixing with the first fluid; Providing a dispenser for dispensing the first fluid; And dispensing the first fluid such that the first fluid passes through the second fluid and moves on the surface in a direction opposite to the gravitational direction. The present invention also relates to a method for providing said surface of a designated location in relation to said first fluid in a direction opposite to gravity direction while locating said first fluid in contact with said surface. The invention also relates to an apparatus and an electrowetting device arranged to provide such a method.

Description

[0001] FLUID DISPENSING METHOD [0002]

The present invention is particularly directed to a method of providing a first fluid on a surface for manufacturing an electrowetting display device.

International Publication No. WO 2005/098797 discloses a method for providing an oil layer on the surface of a substrate, particularly suitable for electrowetting display implementations. The surface is initially covered with a layer of water. The dispenser has an opening above the surface in the water layer. Oil is supplied to the dispenser, and oil droplets are formed between the openings and the surface. The surface comprises a hydrophobic first region surrounded by a hydrophilic second region. When the dispenser moves over the surface, the oil droplets are drawn over the first and second areas, replaced with water on the first area by the oil layer, and leave water in the second area.

It is an object of the present invention to provide another method of providing an oil layer on a surface.

The object of the present invention is implemented by a method of providing a first fluid on a surface for manufacturing an electrowetting device, comprising:

a) providing a surface

b) providing an amount of a second fluid incapable of mixing with the first fluid;

c) providing a dispenser for dispensing the first fluid; And

d) dispensing the first fluid such that the first fluid passes through the second fluid and moves on the surface in a direction opposite to the gravitational direction

.

For example, there is gravity as a downward force, and as the dispenser is arranged below the surface, the second fluid moves toward the dispensed surface and contacts the surface. Advantageously, the dispensed first fluid spontaneously moves toward the surface, so that the dispenser can be positioned away from the surface. Therefore, there is no need for careful positioning to dispense the needle to bring the needle adjacent to the surface within a small area as is known in the art. Accordingly, the dispenser may be a simple structure. In addition, by distributing the first fluid in a direction opposite to gravity, the surface is arranged accordingly, and the surface assists in stabilizing a given amount of the first fluid, thus allowing an accurate distribution to the surface. Therefore, the method of the present invention is simple and efficient.

Preferably, the first fluid is less dense than the second fluid. When the first fluid is dispensed, the first fluid rises to the surface via the second fluid without having to bring the dispensing device near the surface to apply the first fluid to the surface. In an electrowetting device, the first and second fluids may be provided at the same density. However, in the case of mass production of such devices, it would be difficult to implement to provide precisely matched densities at the overall operating temperature of the first and second fluids. The method of the present invention can advantageously utilize density differences between fluids to provide a first fluid on the surface in a convenient manner. Moreover, since the fluid is provided on the surface using the intrinsic properties of the fluid, a complicated dispensing device is not required. In addition, exact density alignment of different fluids is not required and provides greater tolerance in manufacturing.

In another embodiment of the invention, the dispenser is arranged to dispense a mixture of a first fluid and an additional second fluid to the excitation, the method comprising the step of dispensing the mixture in step d). The mixture may be an emulsion of the first and second fluids. The surface is more wettable with respect to the first fluid than the second fluid, which is likely to contact the surface when the first fluid is in close proximity to the surface, To form a layer, which means simply coating the surface with a first fluid using the different wetting properties of the fluid with respect to the surface. For example, the surface can be a hydrophobic surface such that the first fluid is non-polar and the second fluid is polar or conductive.

In another embodiment of the present invention, the first fluid has a density substantially equal to the density of the second fluid. Means that the first fluid and the second fluid in the mixture of the first and second fluids have a density that does not rise. By using additives in the fluid to adjust their density, the first and second fluids will have the same density. An electrowetting device comprising a first and a second fluid of the same density can have advantageous performance. For example, if the display is shaken, it may be resistant to the collapse of the structures of the first and second fluids. With the first and second fluids having substantially the same density, the method according to the present invention allows the first fluid to be readily provided on the surface. For example, in a preferred embodiment, the dispenser may be arranged to dispense the first fluid at a rate for passing the second fluid to the surface. Thus, by ejecting the first fluid from the dispenser at an appropriate force, the first fluid can reach the surface, overcoming the tendency of the first fluid to remain in a fixed position in the second fluid due to density matching.

Advantageously, in order to avoid the distortion of monitoring caused by the influence of the meniscus between the first and second fluids that occurs when monitoring from the same side as when distributing the first fluid, The device and the dispenser may be arranged on opposite sides of the surface. Also, monitoring from the same side as during dispensing makes it difficult to observe where to apply the first fluid on the desired surface in effective monitoring. Thus, the dispenser is arranged below the surface, and the monitoring device is arranged on the surface. The surface can be made transparent, and the surface on which the first fluid on the surface is provided can be observed. Moreover, since the monitoring device is arranged on the surface, the device can be placed under the surface, and more particularly when the device is placed between the surface and a part of the manufacturing device, for example a base of a second fluid bath, When positioned, the device can be moved more freely in three dimensions without being disturbed.

In a preferred embodiment of the present invention, the dispenser dispenses the first fluid with the aid of an additional fluid that is not immiscible with the first fluid. The additional fluid can be air and allows a layer of the first fluid to be applied on the surface in an effective manner.

In another embodiment of the present invention, a method comprises providing a third fluid on a second surface, the method comprising:

e) providing the second surface;

f) providing an additional dispenser for dispensing the third fluid; And

g) dispensing the third fluid and moving the third fluid through the second fluid in a direction opposite to the gravitational direction onto the second surface. Advantageously, the method can be used to fabricate an electrowetting display device having two or more switchable display layers. By using the method of the present invention to fabricate at least one display layer, two separate assembled display layers can be joined together without having to reverse one of the display layers, which is an inconvenient and inefficient manufacturing step.

In a preferred embodiment of the present invention, the method includes monitoring the formation of a layer of a first fluid on a surface using a monitoring device, and controlling distribution to a first fluid to provide a layer having a predetermined thickness . This allows the step of providing the first fluid on the surface to be performed in a controllable manner.

In a preferred embodiment of the present invention, the method of the present invention employs a roll-to-roll process for manufacturing an electrowetting device. The roll-to-roll process can be used to manufacture the electrowetting device conveniently and efficiently in large quantities and at low cost. The roll-to-roll process, also known as web processing, means that the device assembly steps are performed continuously without the need to delay or halt the process of the steps being performed. The electrowetting device can be assembled using a thin plate and / or a flexible material suitable for a roll-to-roll process. Therefore, the method of the present invention is fully compatible with the roll-to-roll process and allows the electrowetting device to be manufactured in an efficient manner.

 Other aspects of the invention are defined in the appended claims.

Other features and advantages of the present invention will become apparent from the following description of the preferred embodiments of the present invention, which are given by way of example only, with reference to the accompanying drawings.

1 schematically shows an electrowetting display device manufactured using the method of the present invention.
Figure 2 schematically shows an apparatus for providing a roll-to-roll method of manufacturing an electrowetting apparatus using the method of the present invention.
Figures 3 and 4 schematically illustrate a dispensing method according to an embodiment of the present invention.
Figures 5A, 5B and 5C schematically illustrate a dispensing method according to a further embodiment of the present invention.
Figure 6 schematically shows another electrowetting display device manufactured using the method of the present invention.

1 schematically shows a cross-sectional view of a series of electrowetting elements of an electrowetting display device in which the present invention is produced using a dispensing method. The series of devices shown is shown as the surface on which the layer of the first fluid is formed is inverted compared to the orientation, as described below. The first substrate 2 has an electrode 4 that is deposited as a thin film conductor on a substrate. Each electrode is connected to a signal line 6 to provide a voltage. The electrode is covered by an amorphous fluoropolymer, e. G., A hydrophobic thin layer 8 of AF 1600. The pattern of the hydrophilic thin layer 10, for example SU8, divides the surface of the substrate in the hydrophobic first region 12 between the hydrophilic second regions 10. The hydrophilic layer is a material that is less hydrophobic, i.e., more hydrophilic than the hydrophobic thin layer 8. Therefore, while the term hydrophilicity is used herein, the hydrophilic layer may exhibit hydrophobic properties. In other words, the hydrophobic layer is more wettable than the first fluid, and the hydrophilic layer is more wettable than the second fluid. In this example, the size of the first region is about 20 to 500 square micrometers, such as 160 square micrometers, the second region is about 1 to 50 micrometers, e.g., 10 micrometers wide, and about 3 to 6 micro- Meter height. The substrate 2 with the electrodes, the hydrophobic and hydrophilic layers 4, 8 and 10 can be used in a dispensing method according to the invention using oil as the first fluid, water as the second fluid and air as the additional fluid Is performed. Other combinations of fluids may be used in other embodiments. The dispensing method is described below. After performing the dispensing method, the first region 12 is unevenly covered by an oil layer 14 having a thickness of, for example, 5 micrometers between 3 and 6 micrometers. The height of the oil layer is determined at least in part by the height of the second region, since the height determines the position on the second region where the interface between the first and second fluids is fixed. The second region 10 and the oil layer 14 are covered by the water 16. The water may include salt or other additives to increase the conductivity and / or to broaden the temperature range for device operation. The second fluid, which in this example is used during the dispensing process, is preferably the same fluid as that used in the product comprising the substrate, which prevents the exchange of the second fluid with another fluid after the dispensing method is performed. The second substrate 18 forms a closed space between the first and second substrates. A seal, not shown in Fig. 1, is provided between the first and second substrates 2, 18 to separate the first and second substrates 2, 18 from each other and form a closed space. Such a seal may be provided around the periphery of the display device. The seal therefore determines the spacing between the first and second substrates and defines the display area of the device.

The pattern of hydrophilic layer 10 defines elements on the substrate where the oil layer 14 is confined. Each element has an electrode (4). The other electrode 17 connected to the signal line contacts the water 16 to form a common electrode for a plurality of elements. When a voltage is applied between the common electrode 17 and the electrode 4 of the device, the oil layer 14 in the device moves or breaks to one element side, and the first surface is at least partly covered by the water 16 It is covered. The so-called electrowetting effect is described in more detail in International Patent Application No. WO 03/071346. If the oil and / or water have specific optical properties for the absorption, reflection and / or transmission of light, the device may operate as a light valve, for example a display.

An electrowetting element may be used in a display device, wherein the plurality of electrowetting elements form a display device. A display drive system in the device provides a voltage for setting the device to a desired state.

Figure 2 schematically shows an apparatus for manufacturing an electrowetting apparatus using a roll-to-roll process. The roll-to-roll process is a continuous process involving the supply, processing and assembly of parts layers using a series of rollers. The process may be carried out at room temperature, atmospheric pressure. In this example, the device to be assembled is the device shown using Fig.

The component layers of the device to be described below are similar to some of the devices described in Fig. 1 and are described using the same number incremented by 100, and the corresponding explanation should be applied equally. In this example, each component layer of the apparatus is provided on a separate roller R1. However, in a further embodiment, at least two component layers can be connected to one another and are provided on one roller. The component layer is fed and adjusted by an additional roller R2 between each step of the manufacturing process. The rotational directions of the rollers R1 and R2 are indicated by arrows in Fig. The layers may be fed through a roll-to-roll process at a speed in the range of, for example, about 0.1 to 100 millimeters per second and preferably in the range of about 0.5 to 5 millimeters per second.

The details of the component layers will be described for device fabrication. Considering that rollers are used to provide and adjust the layers during the manufacturing process, each layer is suitably flexible and durable so as not to be damaged by the rollers. At least one of the component layers is punched in a series of notches downwardly with respect to each of the opposite sides of the layers, each of which cooperates with a series of protrusions that surround the periphery of each end of the roller through which the layer passes. With this notch and protrusion structure, contact between the active area of the susceptible component layer and the surface of the roller can be reduced to minimize damage to the active area. For example, a modified roller can be used in combination, so that the component layer can be hung on the roller by the notches and protrusions. The rollers may also be suitably positioned to avoid sensitive areas of the layers that are in contact with the rollers. Also, slippage of the component layer on the roller can be prevented.

The first substrate 102 and the second substrate 118 may be formed as part layers of the device such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), or polyimide . If the display to be manufactured is a reflective display, the first substrate 102 may be a reflective substrate. Electrode 104 is provided as a component layer and may be formed of carbon nanotubes or poly (3,4-ethylenedioxythiophene) (PEDOT) printed according to the desired pattern of electrodes 104. An electrowetting device such as that shown in Figure 1 operates as a capacitor. Thus, the electrode material need not be highly conductive, i. E. Can have high ohmic resistance. Therefore, it is more free to select an appropriate electrode material in the roll-to-roll process and / or to select a method of processing the material. Such an electrode layer can be used to fabricate a direct drive type electrowetting display device. In order to provide a more complex electrode pattern on one substrate, for example an active matrix type of display device, for production use, the multi-layer structure can be manufactured, for example, by Polymer Vision ^TM or Plastic Logic ^TM . The hydrophobic layer 108 can be produced using printing, such as gravure printing in a roll rheol process, which is similar to flex printing, flat-bed technology. A component layer of the pixel wall 110 may be formed using printing, embossing, lamination or lithographic techniques. In the case of embossing, the pixel wall material is provided as a sheet and delivered to the roller in an embossed pattern, and the pixel wall material is stamped with the desired pixel wall pattern. The printing of the pixel walls can be screen printing. A seal layer 20 may be provided on the roller R1. In another embodiment, the seal layer can be combined with another component layer, for example a layer with a pixel wall layer. In addition, the hydrophobic layer and the pixel wall layer can be provided as a bonding layer, for example, by embossing a hydrophobic material.

The first substrate 102, the electrode layer 104, the hydrophobic layer 108 including the hydrophobic first region, the pixel wall layer 110, and the seal layer 20, each of which is an individual component layer, are fed from the roller R1 And the roller R2, wherein the first substrate 102 is the uppermost layer in this embodiment, and is arranged and joined to one another using the arrangement and coupling device 22. [ The component layer is adjusted by a roller using a carrier, or the component layer is suspended between the rollers. Arrangement uses mechanical or optical techniques. The use of mechanical techniques such as pins or rails can be used, for example, in a low resolution arrangement of +/- 0.1 millimeters. Optical technology is required, for example, for pixel-wall arrays with electrode patterns or high resolution arrays, for example +/- 5 millimeters for the arrangement of optional color filter layers in the device. The optical array can use masks at the corners of the layer regions to be processed, these masks can be provided, for example, in the electrode layer and can be removed at the end of the device assembly.

After the arrangement, the layers are bonded together at the same time. The bonding may be a lamination process using an adhesive to bond the component layers together. The adhesive may be provided on the part layer as an additional step in the roll rheol process prior to alignment and bonding. Or alternatively the part layer may already be provided on the roller R1 which is coated with an adhesive and protected by a peel layer which is removed during the roll-to-roll process prior to the arrangement and bonding of the layers. For example, bonding is carried out under suitable conditions to enable effective bonding between the layers at room temperature and atmospheric pressure. Local heat and pressure may be applied to portions of the layers during bonding. The adhesive may be curable to form a suitable bond.

  After bonding, a first fluid layer may be dispensed to form a first fluid layer on the surface of the hydrophobic first region 112 using the dispensing device 23. [ In this distribution, the bonded layer 21 is immersed in an amount of the second fluid 116 held in the bath 26, and moves to the dispensing device while the first fluid is dispensed. The distribution is described in detail below.

The distribution of the first fluid can be selectively monitored using a monitoring device such as a radiation detector 28 and a radiation beam source 29. When manufacturing the device, the first fluid layer has an appropriate thickness for proper operation of the complete display. When monitoring the distribution, the monitoring signal of the monitoring device may be used to appropriately control the distribution of the first fluid to provide the first fluid layer with a predetermined thickness. For example, the speed at which the surface of the hydrophobic first region is moved over the dispensing device or the rate at which the first fluid 114 is dispensed can be controlled.

Monitoring is performed, for example, by measuring the intensity of the radiation passing through the first fluid formed on the surface of the hydrophobic first region. The radiation beam source 29 may be arranged on the same or opposite surface as the detector 28 for a reflective or transmissive display device in production to emit radiation through the first fluid layer previously dispensed on the surface. When the first fluid is color, the first fluid layer absorbs a portion of the emitted radiation depending on the thickness of the first fluid layer. The radiation detector 28 measures the intensity of the radiation after passing through the first fluid layer. If the detected intensity deviates from the range of intensities representing the desired layer thickness, the distribution is properly controlled. In another embodiment, the monitoring device may include a video camera for imaging formation of the first fluid layer. The process of the captured image can be used to control the distribution.

It is advantageous to monitor the formation of the first fluid layer from the opposite side of the surface of the hydrophobic first region as the dispensing device side is positioned. Therefore, since the first fluid is dispensed from the bottom of the surface, monitoring will be performed from above the surface. This is advantageous because it prevents distortion and blocking of the monitored radiation or image caused by the curvilinear meniscus between the first fluid and the second fluid. In another embodiment, monitoring is performed below the surface, and the base of the bath 26 disturbs the three-dimensional required movement of at least a portion of the monitoring device.

After dispensing the first fluid layer on the surface, the thickness may be flattened using a leveler, for example a scraper or blade, positioned at an appropriate distance from the surface to obtain a predetermined thickness of the first fluid layer. The thickness is taken in the direction from the surface to the meniscus between the first and second fluids, and is perpendicular to the plane of the surface. In the embodiment described with reference to Figures 3 and 4, a dispensing device may be employed to form such leveling. In another embodiment, such as that described with reference to Figure 5, the leveler may be separate from the dispensing device and may level the first fluid after distributing the first fluid on the surface. For precise leveling, the rate at which the first fluid layer is moved relative to the leveler can be properly controlled.

The air pocket can be trapped on the hydrophobic surface due to the low wettability of the surface to the second fluid. Such a bladder can be removed during assembly of the device. This can be performed simultaneously when dispensing the first fluid using the dispensing apparatus described below with reference to FIG. 3 or 4. Alternatively, air removal can be a separate process for dispensing, for example by passing a globule of another fluid, such as air, along the hydrophobic surface prior to dispensing the first fluid, The pouch is joined with the air cushion. Separate air removal can be applied prior to dispensing when using the dispensers of Figs. 5a, 5b and 5c, described below.

When the first fluid layer is dispensed, the bonding layer 21 is fed by a roller R2 to an additional arrangement and coupling device 30 for positioning and coupling with the second substrate. The second substrate 118 is fed through the rollers R1, R2 to the further arrangement and joining device 30. [ Additional alignment and bonding device 30 may be used to arrange the second substrate and bonding layer 21 and to use a sealing material such as an adhesive that uses an alignment and bonding technique similar to that previously described for alignment and bonding device 22 And combine them together. The second substrate 118 and the bonding layer 21 are immersed in the second fluid 116 when they are combined. This allows the closed space of the manufactured device to be easily filled with the second fluid 116 without injecting air into the closed space.

After the additional arrangement and combination, the bonding layer 21 comprising the second substrate 118 is drawn out of the bath 26. To complete the fabrication of the electrowetting device, various additional fabrication steps may be performed using suitable devices 32; For example, applying an integrated circuit to a device such as a component for driving operation of the device, installing a signal line and a common electrode, finely dividing the bonding layer 21 to form a multi-electrowetting device, A step of trimming the bonding layer 21 may be performed to remove portions of the layers used in manufacturing that are not necessary for the device-for example, a notch on the side of any component layer such as a substrate .

The distribution of the first fluid is described using Fig. The features of the apparatus similar to those described with reference to FIG. 1 are referred to as being increased by 200 to the same reference numerals, and the description will be applied equally.

Figure 3 shows a cross-sectional view of an embodiment of a dispensing apparatus for providing a method of the present invention. The dispensing device includes a dispenser 34 to provide a first fluid 214 on the surface 36 of the hydrophobic thin layer to provide a hydrophobic area of the bonding layer 1 shown in FIG. The bonding layer 21 comprises a plurality of such surfaces, each being a first hydrophobic region. The dispenser 34 is arranged below the surface 36 to be immersed and covered in the second fluid in this embodiment before the applied first fluid layer. The dispenser 34 is in the form of a needle 38 having a central channel 40 and the surface 36 is moved over the dispenser 34 and has a fixed position in the direction 42 during the roll-to-roll process described above. This direction 42 lies across the plane of the substantially flat surface 36. The first fluid 214 is supplied through the channel 40. The needle has an opening 44, which in operation is located in the second fluid 216 and below the surface 36. Additional fluid 45 is located, in part, in channel 40 and, in part, between opening 44 and surface 36. The additional fluid is incompatible with the first fluid and forms a small aperture 46 between the aperture 44 and the surface 36. The apertures 46 may be in contact with the surface 36 locally.

The first fluid 214 moves as a relatively thin layer along the interface 50 between the first fluid 214 and the additional fluid 45 from the scan 38 to the surface 36, Stable. The leading interface 52 between the second fluid 216 and the first fluid 214 pushes out the second fluid and replaces it with the first fluid. The thickness of the layer 51 remaining on the area of the surface after the passageway of the dispenser depends on the width of the opening 44, the shape thereof, the speed of movement of the dispenser, the distance between the opening 44 and the surface 36 , The viscosity of the fluid, the size of the sphere, the amount of the first and other fluids, the interfacial tension at various boundaries, and the chemical contrast, i.e., the difference in hydrophobicity between the fluid and the various combinations of surface and dispenser. By distribution from below the surface, the surface assists in stabilizing from above the volume of the first fluid and the additional fluid during and after dispensing. Such advantages apply to other embodiments described below.

The first fluid 214 may be non-polar, for example an alkane such as hexadecane or an oil such as a hydrocarbon oil, and in this embodiment a silicone oil. The second fluid 216 may be any fluid incompatible with the first fluid. The second fluid can be polar or conductive and is useful for some applications of the first substrate covered with the first and second fluids. The additional fluid 45 is preferably non-mixable with both the first fluid and the second fluid to stabilize the sphere. The additional fluid may be a gas such as air, nitrogen or argon. This embodiment uses air as an additional fluid. Other non-admixable fluids that can be used are liquid metal, such as carbon fluoride and mercury.

The deposition of the first fluid on the surface can be promoted if the surface has a greater wettability to the first fluid than in the case of the second fluid. In the illustrated embodiment, the surface is an amorphous fluoropolymer, such as a hydrophobic layer, e.g., AF1600. The hydrophobic layer increases the adhesion to the oil surface and blocks water.

Application of additional fluid, such as that shown in Figure 3, may be achieved by the following steps: filling the fluid with the first fluid, pushing a large amount of air into the fluid injection, Inserting a scan, and pushing air out of the scan. The size of the appeal is determined by the amount of air in the injection and the characteristics of the first and second fluids. The injection may be replaced by a reservoir filled with the first fluid and a pump mechanism for dispensing the desired amount of the first liquid.

During dispensing of the first fluid using the dispenser 34, the entrapment of air between the dispenser and the surface is combined with any entrapped air pocket to relax the air pocket from the surface of the hydrophobic area, . When the dispenser moves over the surface, the nozzle acts as a cleaner for the trapped air bladder.

In the embodiments of the present invention and those described using Figures 4, 5a, 5b and 5c, the first fluid has a lower density than the second fluid. The difference in density between the first fluid and the second fluid can be, for example, at least about 0.01 grams per cubic centimeter, and is preferably at least about 0.05 grams per cubic centimeter. As the difference between the density of the first fluid and the second fluid increases, the probability of the first fluid passing through the second fluid and contacting the surface increases. Therefore, a high density difference, for example, about 0.35 grams per cubic centimeter or more is preferable. However, the density difference should be selected so as not to adversely affect the operation of the finished device. The density of the first and second fluids can be fine tuned using additives. For example, the second fluid, which is water, can be densified using salt and has a density of at least 1 gram per cubic centimeter, and in some instances greater than 1.1 grams per cubic centimeter. Assuming that the first fluid has a lower density than the second fluid, the first fluid moves toward the surface, in the opposite direction of gravity, until it comes into contact with the surface. In other words, the first fluid rises through the second fluid to reach the surface, and the surface is arranged in the volume of the second fluid. Upon contact with the surface, the first fluid wetts the surface to form a first fluid layer in contact with the surface. This is assisted by the hydrophobicity of the surface.

Figure 4 illustrates a dispensing device according to another embodiment of the present invention having an extended dispenser for providing a layer of first fluid oil through a second fluid on a hydrophobic surface. Features similar to those described above are used to increase the number 300 in the drawings, and the corresponding description applies equally.

Fig. 4 shows a cross section of the dispenser 55 and the bonding layer 321. Fig. The dispenser can be closed on one side by two vertical walls. The dispenser 55 has a U-shape with an opening 56 facing the surface 336. The opening is below the surface of the second fluid 316. The interface between the second fluid and the periphery is not shown in the figure. The dispenser has a first input (58) in the form of a tube for feeding oil to the dispenser and a second input (60) in the form of a tube for controlling the air. The long dispenser may have two or more first and / or second inputs and is regularly spaced over the length of the dispenser to improve control of the fluid. The air forms an extended annulus 62 surrounded by the oil layer 314. The width of the opening 56 is preferably less than 10 mm, for example 2 mm. When the opening is wider than 10 mm, the oil tends to escape from the opening and move upward in the water. The spacing of openings on the surface is preferably less than 2 mm, and in a particular embodiment is 0.1 mm. A small gap between the aperture and the surface facilitates filling of the dispenser by the first fluid through the capillary force.

The dispenser has a hydrophobic surface on the inner wall 64 and on the wall 66 adjacent to the opening 56. The hydrophobic nature fixes the oil to the dispenser. The outer wall 68 of the dispenser in partial contact with water is hydrophilic to prevent contamination with oil. The dispenser can be made of PMMA which is weakly hydrophobic. This material has the advantage of high contact angle hysteresis that improves the positional stability of the oil. Such materials can wet oil or water by simply controlling the oil / water interface movement, and interface peening at the edge of the dispenser adds to the availability of this effect. The first fluid in the figure is fixed on the two outer edges of the wall portion, but can also be fixed on the two inner edges of the wall portion. Hysteresis refers to the difference in contact angle after advancing and retracting the fluid boundary.

The bonding layer 321 moves in a direction 70 substantially perpendicular to the longitudinal axis of the opening 56 and moves to the leading interface 72 between the water and the oil on the surface 336. In this embodiment, the surface is one of a plurality of surfaces corresponding to the pattern of the hydrophobic regions 74, each of which may be a first region or a sub-pattern and a second region of the first region. For example, each sub-pattern is for a display device, and two or more display devices are arranged on a surface in a direction parallel to the long axis of the dispenser. Moreover, a pattern or subpattern may have a form that conveys meaning to an observer, such as a logo. Such subpatterns can be combined with other subpatterns for display functionality, and together provide signal functionality. In a display device, the pattern or subpattern may be switchable as a common display element or may be permanent or non-switchable. In another embodiment, such a pattern or subpattern provides an effect of enhancing a decorative effect, e.g., an observer experience.

The length of the opening is equal to or greater than the size of the pattern parallel to the long axis of the opening. The length should at least be such that the deposition non-uniformity caused at the boundary of the blank 62 occurs outside the pattern. The length of the opening may be substantially the same as the size of the surface in a direction perpendicular to the scan direction. Region 73 between regions 74 is preferably hydrophilic, e.g., covered with SU8, to prevent oil deposition in the region of the surface, which is similar to the hydrophilic region described in FIG.

In the embodiment of the apparatus shown in Fig. 4, the leading interface 72 of the oil 314 is parallel to the boundary line 76 between the first and second regions. Since the oil does not want to contact the second area, the shape of the oil under the dispenser is interrupted along the contact line from hydrophobic to hydrophilic areas. Pinning of the oil on the boundary line during the movement of the dispenser on the surface results in stick-slip movement and becomes a layer of oil deposited with stripes.

Figures 5a, 5b and 5c schematically illustrate another dispenser for dispensing a first fluid, and in accordance with another embodiment of the present invention, the formation of a first fluid layer on a target hydrophobic surface TS of a series of such surfaces, Respectively. For brevity, only a portion of the bonding layer is shown. The features are similar to those described above and are referenced in Figures 5A, 5B, and 5C using an increment of 400 in reference numerals, and the description applies equally.

The dispenser of this embodiment is a tube 80 that is secured within the bath 426 of the second fluid 416. The dispenser is oriented upwards and towards the bonding layer 421 passing over the dispenser in a direction 442 transverse to the plane of the bonding layer 421, similar to the bonding layer passing over the dispenser described with reference to Figures 3 or 4 Has an opening (82). The dispenser is connected to a first fluid supply, not shown, for simplicity.

Referring to FIG. 5A, the target surface TS is not yet covered by the first fluid layer. The corresponding surface that is further ahead of the target surface TS of the passing direction 442 is already covered by the first fluid layer 414. The corresponding surface of the target surface TS at the back, that is, the direction opposite to the passing direction 442, is not covered by the first fluid 414. The dispenser 80 dispenses the first fluid 414 through the opening 82 into the second fluid 416 in the form of a liquid crystal 84. The volume of the droplet can be controlled depending on the size and shape of the opening 82 and the flow rate of the first fluid supplied to the dispenser 80. The gap between the dispenser and the target surface TS is selected according to the speed at which the bonding layer 421 passes over the dispenser so that the droplets of the first fluid are raised and contacted and the target surface TS and, .

5B, the droplets 84 of the first fluid pass through the second fluid 416 to contact the target surface TS and begin to soak. Additional droplets 85 are dispensed to wet the surface passing through the dispenser after the target surface TS. 5C, the droplets 84 are dispersed to wet the entire target surface TS and form a layer 86 on the target surface TS of the first fluid. The additional droplet 85 contacts the next surface and begins to soak, and another droplet 88 is dispensed.

The above-described embodiments are to be understood as examples of the present invention. A further embodiment of the invention can be envisaged. For example, a separate dispensing device may be used to dispense the first fluid. An example of a dispenser has been described with reference to Figs. 3 and 4. Fig. A detailed description of such dispensers and further embodiments that may be utilized in accordance with the present invention are set forth in British Patent Application 0707201.0, the contents of which are incorporated by reference. In addition, the dispenser described with reference to Fig. 5A dispenses the first fluid as a continuous flow instead of distributing the first fluid as individual droplets. In a separate embodiment, the first fluid may be closely located or directly in contact with the surface by the dispensing device, and is for dispensing the first fluid in a direction opposite to gravity. This, in contrast to other embodiments, dispenses the first fluid away from the surface. The dispensing device may also contact the surface during dispensing. In another embodiment, it is preferred that the different target surfaces are covered with a differently colored first fluid. This may be accomplished by providing a plurality of dispensers, for example, by dispensing a differently colored first fluid, and controlling the dispensing of differently colored fluids, respectively, similar to that described above with reference to Figure 5a have. A dispenser of an inkjet type loaded with a differently colored first fluid may be used to dispense a differently colored first fluid. In another embodiment, the dispensing device may be located outside the second fluid and is arranged to dispense the first fluid to the second fluid, wherein the first fluid moves toward the surface.

The above-described embodiment relates to the distribution of the first fluid, wherein the first fluid has a lower density than the second fluid. In another embodiment of the present invention, the first and second fluids may have substantially the same density as each other. This can be achieved by fine tuning the density of the fluid using the additive. In this embodiment, the dispenser may be arranged to dispense the first fluid at a rate to contact the surface through the second fluid. For example, the discharge of the first fluid from the dispenser using pressure can be controlled depending on the volume of the second fluid between the dispenser and the surface, so that any gravity and attraction from the second fluid, 2 tend to remain in a fixed position within the fluid. In one example, the dispenser and surface are spaced from each other by an interval of about 5 mm, preferably by an interval of less than 2 mm. In another predicted embodiment, the first fluid may be more dense than the second fluid, and may be applied to the surface by being discharged under pressure, as described above, or by dispensing a first fluid adjacent the surface, Pull the fluid out.

In another embodiment of the invention, the dispenser may be arranged to dispense a mixture of the first fluid and the other second fluid, for example as an emulsion. When the first fluid has a lower density than the second fluid, the first fluid rises through the emulsion to contact and wet the surface to separate the first fluid from the second fluid. In another embodiment, the first and second fluids are substantially in densities. Next, the affinity of the first fluid for wetting the hydrophobic surface preferentially over the second fluid is appropriately distributed near the surface of the emulsion, causing the first fluid to attract and wet the surface, resulting in the first fluid and the second fluid From the emulsion.

In the above-described method of manufacturing a device, the component layers are simultaneously bonded prior to the distribution of the first fluid. Alternatively, for the start of a roll-to-roll process, a pre-bonded component layer is provided on a roller to prepare for the distribution of the first fluid thereon. Pre-bonded layers can be created, for example, starting from the first substrate and stacking each layer individually on top of each other. The underlying layer is processed to produce the adjacent layer above by printing suitable material, for example on the underlying layer. Alternatively, the next layer may be previously prepared and simply laminated to the lower layer.

A method of manufacturing an electrowetting device using the present invention has been described for manufacturing a display device having a single switchable display layer on a first substrate. The present invention is also advantageous in fabricating an electrowetting display device having two or more switchable display layers. An example of a display device having two display layers is shown in Fig. Similar features to those described above have been described herein and in FIG. 6 with the same reference numerals increasing by 500, and the corresponding description should apply equally. A second display layer is provided on the second substrate 518. The second display layer has a structure similar to the first display layer on the first substrate so that the electrode 90, the signal line 92, the hydrophobic layer 94, the hydrophilic layer 96, 98), which is similar to the corresponding feature of the first display layer described above. The third fluid layer 99 covers each hydrophobic area 98, the third fluid is unmixable with the second fluid, and perhaps has the same properties as the first fluid. The third fluid may be switched using an electrowetting force similar to the switching of the first fluid. Details of examples of an electrowetting display having two or more display layers are more fully described in International Patent Application W003 / 071346.

To manufacture two display layer devices using the roll-to-roll process described above, a first display layer is fabricated as described above using Fig. The second display layer may be prepared separately using one of the methods described above for manufacturing the first display layer. The first and second display layers may be provided in the same vessel as the vessel of the second fluid to dispense the first and third fluids, respectively. The method of dispensing a third fluid includes providing at least one second surface that is at least one hydrophobic area 98, providing another dispenser for dispensing a third fluid, and providing a third fluid in a direction of gravity And dispensing a third fluid to contact a second surface that has passed the second fluid in an opposite direction.

The first and second display layers are separately fabricated and are arranged and bonded together using, for example, the above-described additional arrangements and joining devices. It is desirable to couple the first and second display layers together in a plane that bisects the second fluid more than the first fluid, for example, in a plane substantially midway between the first substrate and the second substrate. Alternatively, an oil-resistant sealing material may be used to join the first and second display layers along a plane bisecting the first or third fluid layer. The sealing material may be applied before or after dispensing the first and third fluids.

Dispensing the first and third fluids from below the bonding layer to bond along a substantially vertical plane in a manner similar to that shown in Figure 2 for one display layer and a second substrate, , There is no need to turn the manufactured display layer up to 180 DEG, which is an inefficient and difficult operation that can damage the manufactured display.

It is predictable that the present invention can be advantageously used to manufacture a display device having two or more switchable display layers using a roll-to-roll process similar to the first and second display layers described above.

Materials and / or components other than those described above may be used for the fabrication of the electrowetting device. For the roll-to-roll process, any material or component layer that is flexible and thin pieces and therefore suitable for adjustment by the rollers is predicted. For example, for an electrowetting display device using a backlight, after the second substrate is bonded to the display layer, the backlight may be attached to the display device during the final stage of assembly. Alternatively, a backlight layer may be provided as a component layer for bonding with the other component layers described above. Examples of such flexible backlight layers include more conventional structures using organic light emitting diodes (OLEDs) or polymer light paths. From the above, an additional component layer can be included in the apparatus by, for example, a roll-to-roll process for the colored filter layer.

 The method of manufacturing a display device comprising the method of the present invention has been described so far in the context of a roll-to-roll process and includes applications to such. The present invention is not limited to use in roll-to-roll processes, but may be employed for other manufacturing processes. For example, an electrowetting display device can be fabricated by applying each component layer or combination of component layers to the top of the underlying layer without a roller, and subsequently treating the underlying layer to form the overlying layer, By inverting the final bonded layer prior to application, the first fluid can be applied to the hydrophobic surface using the method of the present invention. Alternatively, one of the switchable display layers may be fabricated using the method of the present invention, and the second display layer may be fabricated using a method of dispensing the first fluid as described above.

In a non-roll-to-roll process utilizing the present invention, the bonding layer may pass back and forth over the dispensing device instead of continuously passing in one direction over the dispensing device. In practice, this may be advantageous for flattening the first fluid layer applied to the hydrophobic surface by filling the thinner layer portion than desired and smoothing the thicker portion.

A method of dispensing a first and a third fluid using a dispensing device at a fixed location below a bonding layer passing over the head has been described. In such an embodiment, the dispensing device may instead be provided through an opening in the bath. In a separate embodiment, the bonding layer may be fixed and the dispensing device may pass downward to dispense the first and / or third fluid.

The features described in connection with any embodiment may be used alone or in combination with other described features and may be utilized in combination with one or more features of any other embodiment or combination of other embodiments. Also, equivalents and modifications not described above may be employed without departing from the scope of the invention, which is defined in the appended claims.

Claims (30)

A method of providing a first fluid on a surface for manufacturing an electrowetting device,
a) providing said surface;
b) providing an amount of a second fluid incapable of mixing with the first fluid;
c) providing a dispenser for dispensing the first fluid; And
d) dispensing the first fluid such that the first fluid passes through the second fluid and moves on the surface in a direction opposite to the gravitational direction
≪ / RTI > The method of claim 1, wherein the first fluid has a lower density than the second fluid. 3. The method of claim 2, wherein the difference between the density of the first fluid and the density of the second fluid is at least 0.01 grams per cubic centimeter. 4. The method of claim 3, wherein the difference is at least 0.35 grams per cubic centimeter. The dispenser of any one of claims 1 to 4, wherein the dispenser is arranged to dispense a mixture of the first fluid and the excitation to the second fluid, the method further comprising the step of dispensing the mixture in step d) / RTI > The method of claim 1, wherein the first fluid has a density substantially equal to the density of the second fluid. 7. The method of claim 6 wherein the dispenser is arranged to dispense a first fluid at a rate for passing a second fluid to the surface. The method of any one of claims 1 to 4, 6, or 7, wherein the surface is provided in a second amount of the second fluid. The method of any one of claims 1 to 4, claim 6 and claim 7, wherein the area of the surface is more wettable with respect to the first fluid than with the second fluid, Wetting the surface to form a layer of the first fluid adjacent the surface. 10. The method of claim 9, wherein the area of the surface is a hydrophobic surface, the first fluid is non-polar and the second fluid is polar or electrically conductive. 10. The method of claim 9, comprising monitoring the formation of the layer on the surface using a monitoring device and controlling the distribution of the first fluid to provide the layer with a predetermined thickness. 12. The method of claim 11, wherein the monitoring device and the dispenser are arranged on opposite sides of the surface. The dispenser of any one of claims 1 to 4, claim 6 and claim 7, wherein the dispenser is arranged below the surface in the gravitational direction and the first fluid is dispensed to rise through the second fluid towards the surface How. The method of any one of claims 1 to 4, 6, or 7, wherein the dispenser dispenses the first fluid with the aid of additional fluid that is not immiscible with the first fluid. 15. The method of claim 14, wherein the dispenser provides the additional fluid to form a globule of the additional fluid between the dispensing opening of the dispenser and the surface. The method according to any one of claims 1 to 4, claim 6 and claim 7, wherein the surface is substantially flat and the method comprises moving the surface and the dispenser relative to each other in a direction lying on a plane of the surface And moving the surface relative to the dispenser, or moving the dispenser relative to the surface. The method according to any one of claims 1 to 4, 6, or 7, comprising providing a third fluid on a second surface,
e) providing the second surface;
f) providing an additional dispenser for dispensing the third fluid; And
g) dispensing the third fluid such that the third fluid moves on the second surface through the second fluid in a direction opposite to the direction of gravity
≪ / RTI > The method of any one of claims 1 to 4, 6, or 7, comprising providing a third fluid on a second surface, the method comprising:
e) providing the second surface;
f) providing an additional dispenser for dispensing the third fluid; And
g) dispensing the third fluid such that the third fluid moves in the gravity direction through the second fluid onto the second surface
≪ / RTI > The method according to any one of claims 1 to 4, 6, and 7, employing a roll-to-roll process to manufacture the electrowetting device. A method of providing a first fluid on a hydrophobic surface for manufacturing an electrowetting device, the method comprising: positioning the first fluid in contact with the surface, In a direction opposite to the direction of gravity. 21. The method of claim 20, comprising using an amount of a second fluid to position the first fluid in contact with the surface. An apparatus arranged to provide a method according to any one of claims 1 to 4, 6, 7, 20 and 21. 23. The apparatus of claim 22, employing a roll-to-roll process. An electrowetting device comprising a closed space defined by at least a surface and a substrate, wherein the closed space encompasses a first fluid and a second fluid that are not mutually compatible, and wherein the first fluid includes at least one of a first fluid and a second fluid, Is provided on said surface using a method according to any one of claims 1, 7, 20 and 21.
6. The method of claim 5, wherein the mixture is an emulsion of the first fluid and the second fluid. A method of providing a first fluid on a surface for manufacturing an electrowetting device, the method comprising:
a) providing said surface;
b) providing a dispenser for dispensing a mixture of the first fluid and the second fluid;
c) dispensing a mixture of the first fluid and the second fluid from the dispenser; And
d) forming a layer of said first fluid on said surface, said first fluid of said layer being separated from said second fluid of said mixture,
≪ / RTI > 27. The method of claim 26, wherein the surface has a greater wettability to the first fluid than the second fluid, and the greater wettability aids in the separation of the first fluid from the second fluid of the mixture. 29. The method of claim 27, wherein the first fluid separates from the second fluid of the mixture when the dispensed mixture contacts the surface. 29. The method of claim 28, wherein the first fluid is non-polar and the second fluid is a polar or conductive fluid, the surface being a hydrophobic surface. 29. The method of any one of claims 26 to 29, wherein the mixture is an emulsion of the first fluid and the second fluid.

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