JP2010524039A - Dispensing method and dispensing apparatus - Google Patents

Abstract

Dispensing method and dispensing apparatus. A method of providing a first fluid layer on a surface region (2) using a dispenser (3) having an opening (8). The method comprises providing on the surface a layer of a second fluid (7) that is immiscible with the first fluid. The method also places a dispenser opening in the second fluid above the region and dispenses the first fluid (6) assisted by the third fluid (9) from the opening. Depositing on the first region, the third fluid being immiscible with the first fluid.
[Selection] Figure 1

Description

  The present invention relates to a method of providing a first layer of fluid on a first region of a surface using a dispenser. The invention also relates to an apparatus for carrying out the method.

  International application WO 2005/098797 discloses a method for providing an oil layer on the surface of a substrate, which is particularly suitable for the production of electrowetting displays. The surface is first covered with a layer of water. The dispenser has its opening in the water layer and above the surface. Oil is fed into the dispenser and oil drops are formed between the opening and the surface. The surface includes a first hydrophobic region surrounded by a second hydrophilic region. As the dispenser moves over the surface, the oil droplets are pulled over the first and second areas, the water on the first area is replaced by a layer of oil, and the water is on the second area. Remain.

  A drawback of this method of providing the oil layer is that it is difficult to control the thickness of the oil layer.

  An object of the present invention is to provide a method capable of easily controlling the thickness of an oil layer.

The object is to provide a first fluid layer on a first region of a surface using a first dispenser having an opening, comprising:
Providing a layer of a second fluid that is immiscible with the first fluid on the surface;
Positioning the opening of the first dispenser in a second fluid above the first region;
Dispensing a first fluid from a assisted opening and depositing on the first region;
Dispensing is accomplished by a method that assists with a third fluid, wherein the third fluid is immiscible with the first fluid.

  The addition of the third fluid provides an additional degree of freedom to control the deposition of the first fluid on the surface. Specifically, the third fluid can be used, for example, to remove air pockets trapped on the surface during the provision of the second fluid layer. The removal of the pocket improves the deposition of the first fluid on the surface. Immiscibility ensures that only the first fluid is deposited without including the supporting third fluid, and the effect of the third fluid is affected by mixing with the first fluid. Do not. The stability of the method is increased when the second fluid and the third fluid are also immiscible.

  In a first embodiment of the method, the third fluid is added using a second dispenser having an opening disposed in the second fluid. The removal of the trapped pocket can be performed separately from providing the first fluid layer. For example, the second dispenser can be scanned one or more times over the surface, followed by the first dispenser being scanned one or more times. If the second fluid and the third fluid are immiscible, mixing of the second fluid and the third fluid is avoided.

  The third fluid can be added from the opening of the second dispenser to form a third fluid microsphere between the opening and the surface. The globules appear to be effective in removing eg air pockets trapped on the surface.

  A second dispenser having an opening disposed in the second fluid can also be applied independently of the first dispenser and the first fluid, to remove trapped eg air pockets from the surface. Can be used for

  The second dispenser may precede the first dispenser when scanning the surface, but the first dispenser advantageously precedes the second dispenser when scanning the surface. When the first fluid layer is deposited on the surface, the trapped pockets are more likely to be removed by the third fluid spheres than when the first fluid has not yet been deposited. . In addition, thereby, the thickness of the first fluid deposition layer becomes more uniform.

In a second embodiment of the method, the third fluid is added from the opening of the first dispenser. In this case, the amount and location of the third fluid can be adjusted to affect the amount and method of deposition of the first fluid. Thereby, control of the thickness of the deposited layer of the first fluid, particularly the uniformity of the thickness can be improved. In a special version of the second embodiment, the method
Dispensing a third fluid from an opening of the dispenser to form a third fluid microsphere between the opening and the surface;
Dispensing the first fluid from the opening and moving along the interface between the second and third fluids and depositing on the first region.

  The interface between the third fluid sphere, the dispenser opening and the surface provides a path for the first fluid to move from the dispenser opening to the surface. The amount of the first fluid deposited on the first region can be controlled by the size of the microspheres. The larger the microsphere, the thicker the first fluid layer on the first region. This filling can be controlled in many applications so accurately that post-filling leveling of the deposited first layer, for example by a doctor blade, is no longer necessary.

  The deposition of the first fluid is improved when the first region has a lower wettability for the second fluid than for the first fluid. The difference in wettability facilitates replacement of the second fluid with the first fluid on the surface.

  The first, second and third fluids can be liquids. In a special embodiment of the method, the first fluid is a first liquid, the second fluid is a second liquid, and the third fluid is a gas. The interface between the gas and the second liquid forms a good path for the first liquid to move from the dispenser to the surface.

  When the second fluid is polar or conductive, the surface provided with the first and second fluids and forming part of the substrate is particularly suitable for use in switchable optical elements such as electrowetting displays. Is suitable.

  The gas can be air that happens to form good spherules. When a layer of the second fluid is applied to the surface by either dispensing the second fluid onto the surface or immersing an item having a surface in the second fluid, the air pocket is Due to its low wettability to the second fluid, it can be trapped on the first region. During dispensing of the first fluid, the air globules between the dispenser and the surface become integral with the trapped pocket, thereby releasing the air pocket from the first region and making the entire region into the first region. Make it available to the fluid. As the dispenser moves over the surface, the spheres act as a trap for the trapped air pockets.

  The method has a second region adjacent to the first region, the second region having a higher wettability with respect to the second fluid than with the first fluid. Can be advantageously used to apply the first fluid. Due to this difference in wettability, the first fluid adheres preferentially to the first region and does not adhere to the second region. Similarly, the second fluid remains attached to the second region and is driven away from the first region. As a result, the first region is covered with a first fluid layer whose thickness depends inter alia on the size of the spherules, and the second region is still covered with the second fluid.

  If the size of the first region is small, it can be assumed that the deposited first fluid is close to hemispherical in shape. Such curved deposits are also covered by the term “first fluid layer”.

  If the maximum dimension of the opening of the first and / or second dispenser is less than the minimum dimension of the first region, each region has a desired thickness of the first layer that may be different for each first region. It can be filled exactly as you get.

  If the maximum dimension of the first and / or second dispenser opening is greater than the minimum dimension of the first region, several adjacent first regions can be filled simultaneously, thereby increasing the deposition rate. Can do.

  Since the opening has an elongated shape, the first region can be filled with one sweep of the first dispenser, or air can be removed by one sweep of the second dispenser. The region or pattern of regions can be filled by moving the dispenser stepwise or continuously over the region of the grid pattern. By filling the elongated dispenser by sweeping over the surface, less movement is required and the speed of the deposition process can be increased. The portion of the small sphere where the normal of the interface line between the first and second fluids on the surface is not parallel to the direction of movement can cause local non-uniformity in the thickness of the deposited layer. There is. The elongate dispenser can keep the boundary outside the first region where the first fluid is to be deposited, thereby avoiding a non-uniform thickness of the deposited layer on the first region.

  When the opening and surface of the first dispenser move relative to each other, preferably in a direction substantially perpendicular to the long axis of the elongated shape, the maximum area is covered with one sweep of the dispenser.

  The method is particularly suitable for depositing a first layer on a surface comprising a plurality of first regions separated by a second region and forming a pattern. The uniform thickness of the first layer is achieved when the first fluid is deposited by a dispenser having an elongated opening. The long axis of the elongated shape of the opening preferably has at least the same length as the dimension of the pattern parallel to the long axis. When the first fluid is deposited on the pattern with multiple sweeps and a portion of the small sphere passes twice over the first region, the thickness of the layer deposited on the first region is small. This is different from the first region where the sphere passes only once. Thus, this thickness is more uniform when the pattern is filled with one sweep of the elongated dispenser than it is filled with multiple sweeps of a smaller dispenser.

  In a special embodiment of the method, the local direction of the boundary between the first region and the second region and the leading interface between the second fluid and the first fluid passing over the boundary Make a non-zero angle. When the leading interface between the opening and the surface of the first and / or second dispenser forms a line tangent to the boundary between the first and second regions, the fluid interface is pinned on the boundary. And tends to cause uneven thickness of the deposited layer of the first fluid. When the boundary line makes a non-zero angle with the interface, there is no longer a line contact, only a point contact that shows little pinning. As a result, the thickness of the first fluid deposition layer becomes more uniform. An angle of 5 ° or more results in a significant improvement in uniformity. Very good uniformity is obtained at an angle of 20 ° or more.

  If the dispenser opening is rectangular, the local direction of the leading interface is parallel to the long axis of the opening. Therefore, the rectangular pattern of the first region should be placed with its boundary line at a non-zero angle with the major axis.

  The oblique scan described above is not only advantageous for a three-fluid deposition method, but also for the two-fluid deposition method in which the first fluid is dispensed into the second fluid without adding a third fluid. Improves uniformity. This advantage also applies to dispensers that deposit the first fluid without the second fluid, or dispensers that add only the third fluid into the second fluid. In the latter case, the direction of the leading interface between the second fluid and the third fluid corresponds to the direction of the leading interface between the second fluid and the first fluid.

  The first dispenser may be scanned once over the surface to deposit a first fluid layer. Higher uniformity of layer thickness is achieved when the first dispenser is scanned over the surface more than once. During the first scan, the first fluid is deposited on the surface, and during one or more subsequent scans, the first fluid is the first fluid if it is underdeposited in the first scan. And redispersed across the surface by removing the first fluid if over-deposited. If the first and second dispensers are used, one or more scans of the second dispenser following the first dispenser also increases the thickness uniformity.

  The surface provided with the first and second fluid layers can be converted to a closed system when the surface is part of the first substrate, between the first substrate and the second substrate. A second substrate is provided that defines a space containing the first fluid and the second fluid.

  A second aspect of the invention relates to an apparatus comprising a first dispenser having an opening for providing a first layer of fluid on a first region of a surface using a method according to the invention.

  In a first embodiment of the apparatus, a second dispenser having an opening is provided for adding a third fluid.

  In the second embodiment of the apparatus, the first dispenser is provided with a first input unit for the first fluid and a second input unit for the third fluid, so that the first fluid The amount and the size of the third fluid globules can be controlled, thereby controlling the amount of the first fluid deposited on the surface.

  In a special embodiment of the device, the opening of the first and / or second dispenser is elongated. The apparatus advantageously comprises a moving stage for moving the dispenser and the surface relative to each other.

  When the apparatus includes a controller for controlling the first fluid and the third fluid, the thickness of the deposited layer of the first fluid can be controlled to increase the accuracy of the deposited layer thickness. The controller can control the amount of the first fluid and / or the third fluid. The input to the controller may be a value provided by a measurement device that determines the thickness of the deposited layer or a measurement device that determines the shape and / or size of the third fluid microsphere. The controller can also use manual input from the operator of the device.

  Further features and advantages of the present invention will become apparent from the following description of preferred embodiments of the invention, given by way of example only, made with reference to the accompanying drawings, in which:

FIG. 2 shows an apparatus according to the invention for dispensing oil onto a surface using air globules. FIG. 6 shows a dispenser for dispensing oil onto a patterned surface. FIG. 6 shows a dispenser for dispensing oil onto a patterned surface. FIG. 3 shows a device having an elongated dispenser. (A) is a diagram showing a first direction for scanning the surface, (b) is a diagram showing a second direction for scanning the surface, and (c) is a third direction for scanning the surface. FIG. It is a figure which shows the cross section of an electrowetting element. It is a figure which shows the controller for apparatuses. FIG. 5 shows a dispenser for dispensing oil and another dispenser for adding air.

  FIG. 1 shows in cross-section a first embodiment of a device according to the invention for dispensing a first fluid onto a surface. The plate 1 has a surface 2 on which a first fluid layer is to be deposited. A dispenser in the form of an injection needle 3 having a central channel 4 is moved in direction 5 over the surface. The first fluid 6 is supplied via the flow path 4. Surface 2 is covered with a layer of second fluid 7. The needle has a circular opening 8, which is located in operation in the second fluid and above the surface 2 during operation. A part of the third fluid 9 is located in the flow path 4 and a part is located between the opening 4 and the surface 2. The third fluid forms a small sphere 10 between the opening 4 and the surface 2. The microsphere 10 can be locally adjacent to the surface 2.

  The first fluid 6 travels from the syringe 3 to the surface 2 along the interface 11 between the second fluid 7 and the third fluid 9 as a relatively thin layer and deposits there as a layer 12. The leading interface 13 between the second fluid 7 and the first fluid 6 pushes the second fluid and replaces the second fluid with the first fluid. The thickness of the layer that remains on the surface area after passing through the dispenser is, among other things, the width and shape of the opening 8, the speed of movement of the dispenser, the distance between the opening 8 and the surface 2, the viscosity of the fluid, and the microspheres. Depending on the size, the amount of the first and third fluids, the interfacial tension of the various interfaces, and the chemical contrast, ie the difference in hydrophobicity between the various combinations of fluids and surfaces and the dispenser.

  The first fluid 6 can be an alkane such as hexadecane or an oil such as a hydrocarbon oil. In the embodiment of FIG. 1, silicon oil is used. The second fluid 7 can be any fluid that is immiscible with the first fluid. The second fluid can be polar or conductive, which is useful in some applications where the plate is covered with the first and second fluids. In the illustrated embodiment, water is used as the second fluid. The third fluid 9 is advantageously immiscible with either the first fluid or the second fluid in order to stabilize the microspheres. The third fluid can be a gas such as air, nitrogen, or argon. In this embodiment, air is used as the third fluid. Other non-affinity fluids that can be used include liquid metals such as fluorocarbons and mercury.

  The deposition of the first fluid on the surface is facilitated when the surface has a higher wettability for the first fluid than for the second fluid. In the illustrated embodiment, the plate 1 can be covered with a hydrophobic layer, for example an amorphous fluoropolymer such as AF1600. The hydrophobic layer makes it easy for oil to adhere to the surface and to repel water.

  Adding the third fluid as shown in FIG. 1 includes the following subsequent steps: filling the syringe with the first fluid, drawing a volume of air into the syringe; This can be accomplished by inserting a syringe into the second layer of fluid 7 and pushing the fluid out of the syringe. The size of the spherules is determined by the amount of air in the syringe and the nature of the first and second fluids. The syringe can be replaced with a reservoir filled with the first liquid and a pump mechanism for dispensing a desired amount of the first liquid.

  FIG. 2 is a top view of a dispenser for dispensing a first fluid onto a patterned surface. The pattern 20 includes a first region 21, in this embodiment a square, that has a higher wettability with respect to the first fluid 6 than with respect to the second fluid 7. The square can be made of AF1600 layers. The adjacent second region 22 has a higher wettability for the second fluid than for the first fluid. Region 22 may be fabricated with layers of various materials including photoresist such as SU8. The maximum dimension of the needle opening 8 in the figure is smaller than the minimum dimension of the square. The needle size allows only the selected first area of the pattern to be filled. When the first fluid is deposited on the first region, the range of the first fluid layer is limited by the second region that repels the first fluid. The second region can be formed by placing another layer having the shape of the second region on the continuous layer forming the first region. If the first region is hydrophobic, the other layer must be hydrophilic. Another layer can be formed, for example, by printing or vapor deposition. The second region can also be formed by a wall having a height that mechanically constrains the first fluid to the first region.

  FIG. 3 is also a top view of a dispenser for dispensing a first fluid onto a patterned surface. The pattern 30 includes a first region 31 and a second region 32. The needle 33 has an opening 34 having a maximum dimension (i.e., diameter) that is greater than the minimum dimension of the first area (i.e., the length of the sides of the first area). When the opening is moved over the pattern on the surface, the plurality of first regions are simultaneously covered with the first fluid, thereby increasing the deposition rate of the device. Since the first fluid has different wettability, it preferentially adjoins the first region and is repelled by the second region.

  There are several advantages to depositing the first fluid through the second fluid layer. Thereby, the outflow of the first fluid is reduced. Thereby, contamination from around the surface is reduced. That is, the contaminant will not go through the surrounding barrier to the second fluid. The presence of the second fluid facilitates deposition localization. The second fluid keeps the first fluid less exposed to oxygen in the air, thereby reducing oxidation of the first fluid. If the first fluid is deposited without the presence of a second fluid layer, the first fluid will be pinned to impurities on the second region. If the second fluid contacts the second region prior to the deposition of the first fluid, the first fluid is less likely to be pinned by impurities. This is because the first fluid must repel the second fluid from a small area around the impurities.

  During the application of the second fluid layer on the surface, air may be trapped on the surface, specifically on the first region near the boundary with the second region. When the dispenser is swept over the first region and the spherule is filled with air, the trapped air becomes integral with the spherule and the location of the trapped air on the first region is the first It is blocked by the fluid. The small sphere functions as a surface air cleaner.

  After deposition on the surface of the first fluid, the plates having the first and second fluids can be used in electrowetting devices such as display devices, optical elements, variable apertures, adjustable lenses, and the like. The second fluid may be removed after deposition of the first fluid, and a plate having only the first fluid is used in the application.

  FIG. 4 shows an elongate dispenser for depositing a first fluid (oil) layer assisted by a third fluid (air) through a second fluid (water) layer provided on the surface. The apparatus which has is shown. This figure shows a cross section of the dispenser and plate. The dispenser can be closed with two vertical walls on the short side. The dispenser 40 is U-shaped and the opening 41 of the dispenser 40 faces the surface 42 of the plate 43. The opening is below the surface of the second fluid. The interface between the second fluid and the surroundings is not shown in the figure. The dispenser has a first input in the form of a tube 44 for supplying oil into the dispenser and a second input in the form of a tube 45 for controlling air. A long dispenser can have two or more first and / or second inputs that are regularly spaced apart in order to improve fluid control. The air forms elongated spherules 46 surrounded by a layer of oil 47. The width of the opening 41 is preferably less than 10 mm, for example 2 mm. When the width of the opening exceeds 10 mm, the oil tends to leak from the opening and move upward in the water. The distance to the opening above the surface is preferably less than 2 mm, and in a special embodiment 0.1 mm. The small opening facilitates filling the dispenser with the first fluid by capillary force.

  The dispenser has a hydrophobic surface on the inner wall 48 and a wall portion 49 adjacent to the opening 41. Hydrophobic properties pin the oil to the dispenser. The outer wall 50 of the dispenser is at least partially adjacent to the water and is hydrophilic to prevent contamination with oil. The dispenser can be made of slightly hydrophobic PMMA. This material has the advantage of high contact angle hysteresis, thereby improving the positional stability of the oil. The first fluid in the figure is pinned on the two outer edges of the wall portion, but may be pinned on the two inner edges of the wall portion. Hysteresis means the difference in contact angle after forward and backward movement of the fluid boundary.

  During the deposition process, the dispenser is moved in a direction 51 substantially perpendicular to the long axis of the opening 41, thereby moving the leading interface 52 between water and oil over the surface 42. The surface includes a pattern of regions 53, each of which can be a first region or a sub-pattern of the first region and the second region. For example, each sub-pattern can be a display device, and two or more display devices are disposed on the surface in a direction parallel to the major axis of the dispenser. Furthermore, the pattern or sub-pattern can have a shape that conveys some meaning to the viewer, such as a logo. Such a sub-pattern provides a marker function and may be combined with another sub-pattern as a display function. In a display device, the pattern or sub-pattern may be switchable like a general display element, or it may be permanent or non-switchable. In another embodiment, such a pattern or sub-pattern provides a decorative effect, for example to enhance the viewer's experience.

  The length of the opening is substantially the same as or longer than the dimension of the pattern parallel to the long axis of the opening. The length is at least large so that uneven deposition caused at the boundary of the small spheres 46 occurs outside the pattern. The length of the opening can be approximately equal to the size of the surface in a direction perpendicular to the scanning direction. The area between the areas 53 is preferably hydrophilic, for example covered with SU8, so that oil does not accumulate in this area of the surface.

  In the apparatus embodiment shown in FIG. 4, the oil leading interface 52 runs parallel to the boundary line 54 between the first and second regions. Since the oil 47 does not want to be adjacent to the second region, the shape of the oil under the dispenser is disturbed along the contact line from the hydrophobic region to the hydrophilic region. Pinning on the oil boundary can cause stick-slip motion as the dispenser moves over the surface, thereby creating a striped oil layer.

  FIG. 5a shows the first direction of the dispenser 60 relative to the surface having the pattern 61 of the first and second regions disposed on the plate 62. FIG. The scanning direction is indicated by an arrow 63. The first direction is the same as the direction shown in FIG. FIG. 5B shows a second direction in which the plate 62 rotates with the pattern 61 at an angle of about 8 degrees compared to the direction in FIG. The leading interface 52 of the dispenser then makes the same 8 degree angle with respect to the boundary line 54. Since the interface and boundary line no longer have line contact but only point contact, the pinning effect is strongly reduced and the thickness of the deposited layer is more uniform than in FIG. The uniformity improvement is observed at angles greater than 5 degrees, and at angles greater than 22.5 degrees, the uniformity is not further improved significantly. FIG. 5c shows another configuration, where the plate 63 has one of its edges parallel to the dispenser 60 and the pattern 64 makes an angle not equal to zero with respect to the leading interface of the dispenser. Has a border.

  The leading interface in the case of a straight elongate dispenser is straight and is in the same direction as the major axis of the dispenser opening. If the dispenser opening is curved in a plane parallel to the surface, the leading interface will also be curved. In order to avoid the stick-slip motion described above, the local direction of the leading interface should make a non-zero angle with the direction of the boundary line.

  Inclined filling as shown in FIGS. 5b and 5c has been described for a filling process using three fluids, but the first fluid is on the surface in the second fluid. It is also advantageous for the filling method dispensed. This is because a similar stick-slip motion occurs in this case. Inclined filling is equally advantageous in a one-fluid filling method in which one fluid is deposited on a surface in air or vacuum.

  FIG. 6 shows a cross section of a series of electrowetting elements fabricated using the deposition method according to the present invention. The first substrate 70 is provided with an electrode 71 deposited as a thin film conductor on the substrate. Each electrode is connected to a signal line 72 for supplying a voltage. The electrode is covered with a thin hydrophobic layer 73 made of amorphous fluoropolymer AF1600. The thin hydrophilic layer 74 pattern of SU8 divides the surface of the substrate into hydrophobic first regions 75 between hydrophilic second regions 74. The size of the first region is 160 micrometers square, and the second region has a width of 10 micrometers and a height of 3-6 micrometers. The first substrate 70 provided with the layers 71, 73 and 74 may be made of oil as the first fluid, water as the second fluid and air as the third fluid, or another combination of fluids. Is used to apply the deposition method according to the present invention. After performing the method, the first region 75 is uniformly covered with an oil layer 76 having a thickness of 3-6 micrometers, for example 5 micrometers. The second region 74 and the oil layer are covered with water 77. The water can contain salt to increase the conductivity of the water and widen the temperature window for the process. The second fluid (water in this example) used during the method is preferably the same as the fluid used in the product including the substrate, which means that the method is performed with another fluid. After that, the second fluid is not changed. The second substrate 78 forms a closed space between the first substrate and the second substrate. This space is protected from the surroundings by an encapsulant (not shown) attached to both substrates.

  The pattern of layer 74 defines an element on the substrate, and oil layer 76 is limited to that element. Each element has an electrode 71. Another electrode 79 connected to the signal line 80 is in contact with the water 77 and forms a common electrode for a plurality of elements. When a voltage is applied between the common electrode 79 and the electrode 71 of the element, the oil layer 76 in that element moves to or separates from the side of the element, and the first surface is at least partially water 77. Covered with. This so-called electrowetting effect is described in more detail in the international patent application WO 03/071346. If the oil and / or water has intrinsic optical properties for light absorption, reflection and / or transmission, the element can act as a light valve, for example in a display.

  The electrowetting element can be used in a display apparatus in which a plurality of electrowetting elements form a display device. A display drive system in the device provides a voltage to bring the device to the desired state.

  FIG. 7 shows an apparatus for depositing a layer on a surface according to the present invention. The tray 82 can be filled with a second fluid. The tray includes a stage 84 on which a substrate can be placed. A dispenser 85 having an opening 86 on the lower side is mounted on a translation stage (not shown) that allows the dispenser to sweep over the stage 84. Alternatively, the dispenser is fixed and the surface is placed on a translation stage. In operation, the dispenser opening is below the level of the second fluid. The first container 87 for the first fluid is connected to a first control unit 88 that controls the amount of the first fluid to be discharged from the connecting portion 89 to the dispenser 85, for example, a valve or a pump. Similarly, the second container 90 for the third fluid is connected to the second control unit 91 for discharging the third fluid from the connecting portion 92 to the dispenser. If the third fluid is air, the second container can be omitted and the control unit 91 can draw air from the surroundings, preferably through a filter, or discharge excess air. . The coupling 92 can also be used to evacuate air from the dispenser if the size of the spherules must be reduced or if a significant amount of air is removed from the pocket.

  The controller 93 provides a signal for setting the first and second controllers to a desired setting. The apparatus can include a measuring device for determining the thickness of the deposited layer. The thickness value can be used as an input to set the control unit. The apparatus also provides a third fluid microsphere shape and / or size, or volume of the first fluid between the dispenser and the surface, for example using a camera observing the dispenser in the direction of its long axis. It is also possible to use an input for setting the control unit. The height above the surface of the dispenser can be maintained at a desired value, for example by measuring the height at the two distal ends of the elongated dispenser and keeping these heights equal. The controller can also use manual input from the operator of the device instead of measurements.

  FIG. 8 shows an alternative embodiment of the method according to the invention. A dispenser 100 filled with the first fluid 6 from the tube 101 and having an opening in the layer of the second fluid 7 is scanned in the direction 102 over the surface 42 of the plate 43 so that the first fluid is on the surface. Layer 103 is deposited. A dispenser 105 filled with the third fluid 9 from the tube 106 and having an opening in the layer of the second fluid 7 scans the surface 42 in the direction 107 following the dispenser 100. The third fluid forms a small sphere between the opening of the dispenser 105 and the surface 42. After providing a second layer of fluid on the surface, the microspheres remove pockets of air trapped on the surface.

  The above embodiments are to be understood as illustrative examples of the invention. Another embodiment of the invention is envisaged. Features described for any one embodiment may be used alone or in combination with other features described, and may include one or more features of other embodiments, or any of the other embodiments It should be understood that combinations and combinations can also be used. Furthermore, equivalents and modifications not described above may also be used without departing from the scope of the invention as defined in the appended claims.

Claims (29)

A method of providing a first layer of fluid on a first region of a surface using a first dispenser having an opening, comprising:
Providing a layer of a second fluid that is immiscible with the first fluid on the surface;
Disposing the opening of the first dispenser in the second fluid above the first region;
Dispensing the first fluid from the opening and depositing on the first region;
With
The method wherein the dispensing is assisted by a third fluid and the third fluid is immiscible with the first fluid.   The method of claim 1, wherein the third fluid is added using a second dispenser having an opening disposed in the second fluid.   The method of claim 2, comprising adding the third fluid from the opening of the second dispenser to form a sphere of the third fluid between the opening and the surface.   4. A method according to claim 2 or 3, wherein the first dispenser precedes the second dispenser when scanning the surface.   The method of claim 1, wherein the third fluid is applied from the opening of the first dispenser. Dispensing the third fluid from the opening to form a sphere of the third fluid between the opening and the surface;
Dispensing the first fluid from the opening, moving along the interface between the second fluid and the third fluid, and depositing on the first region. Item 6. The method according to Item 5.   The method of claim 1, wherein the first region has a lower wettability with respect to the second fluid than with respect to the first fluid.   The method of claim 1, wherein the first fluid and the second fluid are liquids and the third fluid is a gas.   The method of claim 8, wherein the second fluid is polar or conductive.   The method of claim 8, wherein the gas is air.   The first region has an adjacent second region, and the second region has a higher wettability for the second fluid than for the first fluid. Item 2. The method according to Item 1.   The method of claim 11, wherein the surface comprises a plurality of first regions separated by a second region and forming a pattern.   The method according to claim 12, wherein the pattern or a sub-pattern of the pattern has a decorative function or functions as a sign.   The method according to claim 1, 2 or 5, wherein the maximum dimension of the opening of the dispenser is smaller than the minimum dimension of the first region.   The method of claim 1, 2, or 5, wherein a maximum dimension of the opening of the dispenser is greater than a minimum dimension of the first region.   16. A method according to claim 1, 2, 5 or 15 wherein the opening of the dispenser has an elongated shape.   The method of claim 16, wherein the opening and the surface move relative to each other in a direction substantially perpendicular to the elongate major axis.   The surface comprises a plurality of first regions separated by a second region and forming a pattern, and the long axis of the elongated shape has at least the same length as the dimension of the pattern parallel to the long axis. The method of claim 17, comprising:   The boundary line between the first region and the second region, and the local direction of the leading interface between the second fluid and the first fluid passing over the boundary line have a non-zero angle. The method of claim 16.   The method of claim 1, comprising scanning the first dispenser over the surface one or more times.   The surface is part of a first substrate and the method defines the space containing the first fluid and the second fluid between the first substrate and the second substrate. The method of claim 1, comprising providing two substrates.   The method of claim 21, wherein the first substrate and the second substrate form an electrowetting element.   23. An apparatus comprising a first dispenser having an opening for providing a first layer of fluid on a first region of a surface using the method of any one of claims 1-22.   24. The apparatus of claim 23, comprising a second dispenser having an opening for adding the third fluid.   24. The apparatus of claim 23, wherein the first dispenser is provided with a first input for the first fluid and a second input for the third fluid.   26. A device according to any one of claims 23 to 25, wherein the opening of the dispenser is elongated.   26. Apparatus according to any one of claims 23 to 25, comprising a moving stage for moving the dispenser and the surface relative to each other.   26. Apparatus according to any one of claims 23 to 25, comprising a controller for controlling the first fluid and the third fluid.   26. Apparatus according to any one of claims 23 to 25, comprising a controller for controlling the height above the surface of the dispenser.

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