Method for forming a conductive layer, and apparatus for forming a conductive layer

Abstract

To provide a method for forming a conductive layer and a conductive layer formation apparatus that can make the wiring pitch thinner than before.SOLUTION: A method comprises: a first formation process for forming a high surface energy portion by applying energy on a substrate; an applying process for applying a liquid containing a conductive material to the high surface energy portion; and a coating process for applying a liquid containing the conductive material on the high surface energy portion by means of a coating bar that spreads the liquid containing the conductive material by moving over the substrate, and the high surface energy portion on the substrate is divided into a body portion and a dummy portion, and the dummy portion is positioned at least in front of or behind the body portion in the direction of movement of the coating bar.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for forming a conductive layer and a conductive layer forming apparatus.

Background Art

[0002] In recent years, development of an electrostatic actuator that converts energy generated by an electrostatic force into power and moves an object has been underway. The electrostatic actuator is used, for example, in the optical field such as driving of a variable focus lens and driving of a shutter. Further, application of the electrostatic actuator to artificial muscles, prosthetic hands, prosthetic legs, etc. of a robot has been studied. Such an electrostatic actuator is created using a printed electronics technique. For example, when using an electrostatic actuator for artificial muscles of a robot or the like, it has been considered to create an FPC (Flexible Printed Circuits) electrode by, for example, a subtractive method (see, for example, Non-Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When electrostatic actuators created using conventional methods are used, for example, as artificial muscles in robots, a high voltage of over 1kV is required for driving, resulting in the problem of large power supplies. The finer the film pitch, the higher the output and the lower the voltage that can be used, but conventional manufacturing methods (subtraction method) were limited to a wiring pitch of about 100μm.

[0005] The present invention has been made in view of the above-mentioned problems, and aims to provide a conductive layer formation method and a conductive layer formation apparatus that can reduce the wiring pitch compared to conventional methods. [Means for solving the problem]

[0006] (1) To achieve the above objective, a conductive layer formation method according to one aspect of the present invention comprises: a first forming step of applying energy (e.g., ultraviolet light) to a substrate (e.g., FPC film) to form a high surface energy portion (polarized portion); an application step of applying a liquid (ink) containing a conductive material (metal material) to the high surface energy portion; and a coating step of applying the liquid containing the conductive material to the high surface energy portion using a coating bar that spreads the liquid containing the conductive material by moving it on the substrate, wherein the high surface energy portion provided on the substrate is divided into a main body portion and a dummy portion, and the dummy portion is positioned at least in front of or behind the main body portion in the direction of movement of the coating bar.

[0007] (2) Furthermore, in a conductive layer forming method according to one aspect of the present invention, the dummy portion is arranged in a positional relationship such that the front part of the dummy portion is located in the front part in the direction of movement of the coating bar, the main body portion is located, and the rear part of the dummy portion is located in the rear part in the direction of movement of the coating bar, and the coating step is to apply the liquid in the order of the front part of the dummy portion, the main body portion and the rear part of the dummy portion, as described in (1).

[0008] (3) Furthermore, in a conductive layer formation method according to one aspect of the present invention, the rear part of the dummy part is wider in the direction of movement of the coating bar than the front part of the dummy part, as described in (2).

[0009] (4) Furthermore, in a conductive layer formation method according to one aspect of the present invention, the front part and the rear part of the dummy portion have grooves (e.g., slits) that are not high surface energy portions, the conductive layer formation method described in (2) or (3).

[0010] (5) The conductive layer forming method according to one aspect of the present invention, wherein the dummy portion is positioned at least on either the left or right side in the direction of movement of the coating bar relative to the main body, as described in any one of (1) to (4).

[0011] (6) Furthermore, in a conductive layer formation method according to one aspect of the present invention, the coating step is to apply the liquid while spraying an oxygen-free gas at an angle with respect to the vertical direction on the substrate and at an angle with respect to the direction of travel of the coating bar, the conductive layer formation method according to any one of (1) to (5).

[0012] (7) Furthermore, a conductive layer formation method according to one aspect of the present invention, wherein a second forming step of forming a wettability change layer containing a material whose surface energy changes by the application of energy on the substrate is performed before the first forming step, the conductive layer formation method according to any one of (1) to (6).

[0013] (8) To achieve the above objective, a conductive layer forming apparatus according to one aspect of the present invention comprises: a high surface energy applying unit that applies energy to a substrate to form a high surface energy portion; a liquid applying unit that applies a liquid containing a conductive material to the high surface energy portion; and a bar control unit that controls a coating bar that spreads the liquid containing the conductive material by moving on the substrate, wherein the high surface energy applying unit is divided into a main body portion and a dummy portion, and the dummy portion is formed at least in either the front or rear portion in the direction of movement of the coating bar relative to the main body portion.

[0014] (9) Furthermore, in a conductive layer forming apparatus according to one aspect of the present invention, the front part of the dummy part, which is positioned in front of the coating bar in the direction of movement, the main body, and the rear part of the dummy part, which is positioned in rear of the coating bar in the direction of movement, are arranged in a positional relationship, and the bar control unit applies the liquid in the order of the front part of the dummy part, the main body, and the rear part of the dummy part, as described in (8).

[0015] (10) The conductive layer forming apparatus according to one aspect of the present invention, wherein the rear part of the dummy part is wider in the direction of movement of the coating bar than the front part of the dummy part, as described in (9).

[0016] (11) Furthermore, in a conductive layer forming apparatus according to one aspect of the present invention, the front part and the rear part of the dummy part have grooves (e.g., slits) that are not high surface energy parts, the conductive layer forming apparatus according to (9) or (10).

[0017] (12) Furthermore, in a conductive layer forming apparatus according to one aspect of the present invention, the dummy portion is positioned at least to the left or right of the main body portion in the direction of movement of the coating bar, the conductive layer forming apparatus according to any one of (8) to (11).

[0018] (13) The conductive layer forming apparatus according to one aspect of the present invention further comprises a gas injection unit that injects an oxygen-free gas at an angle with respect to the vertical direction on the substrate and at an angle with respect to the direction of travel of the coating bar when applying the liquid, the conductive layer forming apparatus according to any one of (8) to (12).

[0019] (14) The conductive layer forming apparatus according to one aspect of the present invention is further comprising a wettability change layer forming unit that forms a wettability change layer containing a material whose surface energy changes by the application of energy on the substrate, the conductive layer forming apparatus according to any one of (8) to (13). [Effects of the Invention]

[0020] According to (1) to (14), the wiring pitch can be made narrower than before. According to (1) and (8), an appropriate amount of ink can be applied to the main body. According to (2) and (9), an appropriate amount of ink can be applied to the main body, and according to (2) and (9), after printing on the main body, no ink remains on the coating bar, preventing ink from returning to the main body. According to (3) and (10), the front of the dummy part allows an appropriate amount of ink to be left for application to the main body, and promotes the spread of ink perpendicular to the direction of the coating bar's movement, i.e., in the direction of the coating bar, thus enabling uniform ink application to the main body in the left-right direction. Furthermore, according to (3) and (10), the rear of the dummy part prevents excess ink from being left for the next print. According to (4) and (11), the surface energy portion is divided at the groove, which reduces the height of the ink that rises due to surface tension, and prevents excess ink from adhering to the coating bar. According to (5) and (12), the flow of ink can be promoted in the direction of the coating bar's movement, so that the ink can be applied uniformly in the front-to-back direction of the main body. (6) and (13) ensure that the ink follows the coating bar due to the gas, preventing the ink from returning to the ink-coated areas. (7) and (14) enable the formation of a wettability-changing layer (control layer) by applying a polymer solution, making it applicable to polyimide films as well.

Brief Description of the Drawings

[0021] [Figure 1] This is a diagram showing an example of an electrode pattern (conductive layer) created by the conductive layer forming apparatus and the conductive layer forming method of the embodiment. [Figure 2] This is a diagram showing a configuration example of the conductive layer forming apparatus according to the first embodiment. [Figure 3] This is a flowchart of the procedure for creating the electrode pattern according to the first embodiment. [Figure 4] This is a diagram for explaining the procedure for creating the electrode pattern according to the first embodiment. [Figure 5] This is a diagram showing an example of the procedure for creating an electrode pattern by the etching method of the comparative example. [Figure 6] This is a diagram showing an example of an electrode pattern formed by silver nanoprinting in the comparative example. [Figure 7] This is a diagram for explaining the injection direction and angle of nitrogen during the application of the metal nanoink according to the first embodiment. [Figure 8] This is a diagram showing an example of the dummy pattern according to the first embodiment. [Figure 9] This is a diagram showing an example of an actuator created by the conductive layer forming method according to the first embodiment. [Figure 10] This is a diagram showing a configuration example of an electrostatic film actuator by the actuator created by the conductive layer forming method of the first embodiment. [Figure 11] This is a top view of the electrostatic film actuator. [Figure 12] This is a schematic diagram of the operation of FIG. 11 viewed from the side. [Figure 13] This is a diagram showing configuration examples and size examples of the electrostatic film actuators of the comparative example and the first embodiment. [Figure 14] This figure shows an example of the configuration of a conductive layer forming apparatus according to the second embodiment. [Figure 15] This is a flowchart of the procedure for creating an electrode pattern according to the second embodiment. [Figure 16] This is a diagram illustrating the procedure for creating an electrode pattern according to the second embodiment. [Modes for carrying out the invention]

[0022] Embodiments of the present invention will be described below with reference to the drawings. Note that in the drawings used in the following description, the scale of each component has been appropriately changed to ensure that each component is recognizable. In all the figures used to illustrate the embodiments, components with the same function are given the same reference numerals, and repeated explanations are omitted. Furthermore, in this application, "based on XX" means "based on at least XX," and includes cases where it is based on another element in addition to XX. Also, "based on XX" is not limited to cases where XX is used directly, but also includes cases where it is based on something that has been calculated or processed from XX. "XX" is any element (for example, any information).

[0023] [Example of electrode pattern (conductive layer)] First, an example of an electrode pattern (conductive layer) created by the conductive layer forming apparatus and conductive layer forming method of this embodiment will be described. Figure 1 shows an example of an electrode pattern created by the conductive layer forming apparatus and conductive layer forming method of this embodiment. In Figure 1, the longitudinal direction is the x-axis direction and the transverse direction is the y-axis direction. As will be described later, the electrode pattern in Figure 1 is created by printing ink in the x-axis direction on an FPC (Flexible Printed Circuits) film (substrate). The symbol g1 is an enlarged image of the right edge of the electrode pattern. When a closed pattern like the image of symbol g1 is created by the conductive layer forming apparatus and conductive layer forming method of this embodiment, the closed area can be created separately without being filled with ink.

[0024] <First Embodiment> In the first embodiment, an example of a formation method that does not use a wettability-changing layer (control layer) by coating with a polymer solution will be described.

[0025] [Example of a conductive layer forming apparatus configuration] Next, an example of the configuration of the conductive layer forming apparatus 1 will be described. Figure 2 shows an example of the configuration of a conductive layer forming apparatus according to this embodiment. As shown in Figure 2, the conductive layer forming apparatus 1 includes, for example, a control unit 11 and a storage unit 12. The control unit 11 includes, for example, an ultraviolet irradiation control unit 111 (high surface energy application unit), a bar drive control unit 112 (bar control unit), an ink coating control unit 113 (liquid application unit), and a gas injection control unit 114 (gas injection unit). The conductive layer forming apparatus 1 is connected, for example, to an ultraviolet irradiation device 2 (high surface energy application unit), a coating bar 3, an ink supply device 4 (liquid application unit), and a gas injection device 5.

[0026] The ultraviolet irradiation device 2 irradiates ultraviolet light in accordance with the control of the conductive layer forming device 1.

[0027] The coating bar 3, controlled by the ink supply device 4, smooths the metal nano-ink, for example, applied to an FPC film, according to the control of the conductive layer forming device 1.

[0028] The ink supply device 4 is equipped with ink 41 (for example, silver nano-ink). The ink supply device 4 applies the metal nano-ink onto, for example, an FPC film, in accordance with the control of the conductive layer forming device 1.

[0029] The gas injection device 5 is equipped with gas 51 (for example, nitrogen). The gas injection device 5 injects gas in accordance with the control of the conductive layer forming device 1. The gas can be any gas other than an oxygen-free gas, and may be argon or the like.

[0030] The memory unit 12 stores the direction, angle, and amount of nitrogen injection. The memory unit 12 also stores the amount of metal nano-ink to be applied.

[0031] The ultraviolet irradiation control unit 111 controls the ultraviolet irradiation device 2, including the amount of ultraviolet irradiation, the start of irradiation, and the end of irradiation.

[0032] The bar drive control unit 112 controls the start, end, and movement of the coating bar 3 in contact with the film.

[0033] The ink application control unit 113 controls the ink supply device 4, including the start and end of ink application, the amount of ink applied, and so on.

[0034] The gas injection control unit 114 controls the gas injection device 5, including the start and end of injection, injection amount, concentration, etc., of the inert gas.

[0035] [How to create electrode patterns] Next, the method for creating the electrode pattern according to this embodiment will be explained using Figures 3 and 4. Figure 3 is a flowchart of the procedure for creating the electrode pattern according to this embodiment. Figure 4 is a diagram illustrating the procedure for creating the electrode pattern according to this embodiment. In this embodiment, the conductive layer formation is based on the silver nanoprinting method. As indicated by the symbol g11 in Figure 4, the printing direction is the x-axis direction, and the thickness direction of the FPC film is the z-axis direction. Note that the object on which the pattern is formed is not limited to the FPC film. Furthermore, as an example of a metal nanoink used to form an electrode pattern by coating the film, silver nanoink will be explained as an example.

[0036] (Step S1) As shown by the reference numeral g11 in Figure 4, an FPC film 301 for forming a pattern is set in the conductive layer forming apparatus 1.

[0037] (Step S2) As shown by reference numeral g12 in Figure 4, the conductive layer forming apparatus 1 forms a mask 302 on the portion of the wettability control layer where a pattern is not to be formed.

[0038] (Step S3) As shown by the reference numeral g13 in Figure 4, the conductive layer forming apparatus 1 controls the ultraviolet irradiation device 2 and performs exposure by irradiating with ultraviolet light having a wavelength of, for example, 200 nm or less. As a result of this exposure, as shown by the reference numeral g14 in Figure 4, the pattern forming region 303 of the FPC film 301 that has been irradiated with ultraviolet light and is not covered by the mask 302 becomes polarized. Note that inks containing metal become more likely to adhere to the polarized areas.

[0039] (Step S4) As shown by the reference numeral g15 in Figure 4, the conductive layer forming apparatus 1 controls the ink supply device 4 to apply the ink 41 and controls the coating bar 3 to smooth the ink 41 in the x-axis direction. During this printing, the conductive layer forming apparatus 1 controls the gas injection device 5 to inject, for example, nitrogen 314. The direction and angle of nitrogen 314 injection will be described later. As shown by the reference numeral g16 in Figure 4, as a result of smoothing the ink 41 with the coating bar 3 while injecting nitrogen 314, the ink 41 is applied only to the polarized pattern formation region. In this way, the conductive layer forming apparatus 1 prints the ink 41 for forming the electrode pattern on the FPC film 301.

[0040] (Step S5) As shown by reference numeral g17 in Figure 4, the conductive layer forming apparatus 1 controls the ultraviolet irradiation apparatus 2 and irradiates ultraviolet light to cure the ink 41. As a result, as shown by reference numeral g18 in Figure 4, an electrode pattern 305 is formed at a desired position on the FPC film 301.

[0041] Here, as a comparative example, we will describe an example of the procedure for creating an electrode pattern using a general etching method. Figure 5 shows an example of the procedure for creating an electrode pattern using an etching method in the comparative example. In this case, first, the conductive layer forming apparatus prepares an FPC film (g901) and forms copper foil on the FPC film (g902). Next, the conductive layer forming apparatus applies a resist (g903) and then attaches a mask to areas other than the pattern formation area (g904). Next, the conductive layer forming apparatus exposes the area by irradiating it with ultraviolet light (g905) to harden the pattern formation area (g906). After hardening, the conductive layer forming apparatus removes the resist by developing it (g907) and then removes the copper foil other than the pattern formation area by etching (g908). After that, the conductive layer forming apparatus removes the resist from the pattern to complete the formation of the electrode pattern (g909). Note that, as shown in symbol g910, patterns created by the etching method have tapered edges due to the indentation on both sides of the pattern, making it difficult to narrow the pitch between patterns. For this reason, conventional methods could only form electrode patterns with a pitch between patterns of about 100 μm.

[0042] Thus, the conductive layer formation method of this embodiment (Figures 3 and 4) significantly reduces the number of steps and manufacturing costs compared to electrode patterns formed by general etching methods, such as copper foil formation, resist coating, resist removal, and etching.

[0043] [Nitrogen injection] Next, I will explain the nitrogen injection process during printing. Figure 6 shows an example of an electrode pattern formed with silver nanoprinting in a comparative example. In the example in Figure 6, the pitch between patterns is 40 μm, and the pattern was formed without nitrogen spraying during the application of the metal nanoink as in this embodiment, and without forming the guard pattern described later. For example, in the example of image g920, ink accumulated between adjacent patterns g921 and g922, causing the patterns to stick together. Also, in the example of image g930, ink accumulated between closed patterns (g931), causing the patterns to stick together.

[0044] In this embodiment, when applying the metal nanoink, nitrogen is sprayed in the spray direction and angle shown in Figure 6. Figure 7 is a diagram illustrating the direction and angle of nitrogen spraying when applying the metal nanoink according to this embodiment.

[0045] The image labeled g50 is a side view of the coating bar 3. Label g51 indicates the injection angle of the nitrogen 314, and label g52 indicates the direction of travel of the coating bar 3. To avoid interfering with the ink adhering to the pattern and to prevent the film from breaking down without forming a film, it is desirable that the injection angle g51 be a steep angle relative to the FPC film (for example, the angle at which it hits the ink 41 at the bottom of the coating bar 3). Also, the nitrogen 314 is injected from the rear relative to the direction of travel of the coating bar 3. In this embodiment, "film formation" refers to the state in which the ink 41 fills the spaces between patterns and closed patterns due to surface tension.

[0046] The image labeled g60 is a top view of the coating bar 3. Label g61 indicates the direction of nitrogen 314 injection, and label g62 indicates the direction of travel of the coating bar 3. The injection direction should preferably be at an angle (not perpendicular to the coating bar 3) that prevents the ink 41 that has leaked out of the coating bar 3 from being pushed back onto the electrode pattern.

[0047] The flow rate, angle, and direction of the injected gas should be set according to the pattern being created. Furthermore, the reason for using nitrogen during ink application, as in the example above, is that if air is sprayed instead, the metal nano-ink will oxidize and harden more easily.

[0048] As a result, according to this embodiment, it is possible to prevent the formation of an ink film 41 between patterns, in closed patterns, etc.

[0049] [Dummy Pattern] Next, I will explain the dummy pattern used during printing. Figure 8 shows an example of a dummy pattern according to this embodiment. In Figure 8, the symbol g213 indicates a film, and the symbols g211 and g212 indicate the patterns to be created. The symbols g201 to g204 indicate dummy patterns. The dummy patterns g201 and g202 are provided in front of and behind the desired electrode patterns g211 and g212 (main body), with the y-axis direction being the longitudinal direction and the x-axis direction being the short direction. The dummy patterns g203 and g204 are provided to the left and right of the desired electrode patterns, with the x-axis direction being the longitudinal direction and the y-axis direction being the short direction. The desired electrode patterns g211 and g212 are, for example, for the stator and the movable element.

[0050] The effect of the front dummy pattern (g201) (front of the dummy section) is that it can control the amount of ink reaching the electrode pattern, allowing the ink to spread efficiently to the desired pattern. Furthermore, since the front dummy pattern (g201) is positioned perpendicular to the desired pattern, at the start of ink application, this dummy pattern facilitates the spread of ink in the y-axis direction, which is the direction in which the dummy pattern is formed. As a result, a guiding effect is obtained that facilitates the spread of ink in the y-axis direction to the desired pattern.

[0051] The effect of the dummy pattern at the rear (g202) (rear of the dummy section) is to prevent excess ink from getting on other parts of the electrode pattern and to absorb any excess ink.

[0052] Note that if there are too many dummy patterns in the front (g201), they will absorb too much ink, so it is advisable to use fewer dummy patterns in the front than in the rear (g202). The number and width of the dummy patterns should be set according to, for example, the pitch between the patterns to be formed and the ink used. The relationship between the position of the pattern to be formed and the position of the dummy patterns should also be set according to, for example, the pitch between the patterns to be formed and the ink used. Note that if the amount of ink applied can be appropriately controlled so as not to be wasted, the rear dummy pattern (g202) may not be necessary.

[0053] Furthermore, the dummy patterns (g203, g204) placed on the left and right sides of the pattern can absorb excess ink from the left and right sides in the direction of travel. Dummy patterns may also be placed between electrode patterns g211 and g212. In other words, dummy patterns may be placed in areas where the desired electrode pattern is not to be formed. By forming the dummy patterns (g203, g204) in the direction of the desired pattern, the effect of facilitating ink spread in the direction of travel relative to the desired pattern can also be obtained. The dummy patterns (g203, g204) may consist of multiple lines perpendicular to the desired pattern. The left and right dummy patterns may consist of only one of either the left or right side.

[0054] The reason for adding grooves (slits) to the dummy pattern is that if the pattern is too wide, the ink will swell and stick to the coating bar 3 during printing, causing the ink to move to unintended locations. Therefore, in this embodiment, slits are added to the dummy pattern. As a result, according to this embodiment, the surface tension of the adhering ink suppresses the liquid height, making it less likely for the liquid to interfere with the coating bar 3 and thus less likely to scatter.

[0055] The dummy pattern may consist of multiple parallel lines, multiple curves such as sine waves, multiple triangle waves, or multiple square waves. The lines may or may not be equally spaced. Furthermore, the dummy pattern does not have to consist of multiple lines; it may consist of multiple patterns with gaps between them (e.g., geometric patterns).

[0056] After printing the ink with the dummy pattern, the dummy pattern portion is separated and the film is used, for example, as an actuator.

[0057] [Example of an actuator created using a conductive layer formation method] Next, we will describe an example of an actuator created using a conductive layer formation method. Figure 9 shows an example of an actuator created by the conductive layer formation method according to this embodiment. Codes g301 and g304 represent one-phase patterns. Codes g302 and g305 represent two-phase patterns. Codes g303 and g306 represent three-phase patterns. Code g307 is a closed pattern section used to connect the same one-phase patterns (g301 and g304). Code g311 is a bus line on the front surface. Code g312 is a bus line on the back surface. Code g313 is a connection point that connects the second phase (g305) to the pattern on the back surface via a through-hole.

[0058] Note that the actuator pattern in Figure 9 shows a portion of the pattern created using, for example, the electrode pattern shown in Figure 1.

[0059] [Example of an electrostatic film actuator] Next, an example of an electrostatic film actuator will be described using an actuator created by the conductive layer formation method of this embodiment. Figure 10 shows an example of the configuration of an electrostatic film actuator using an actuator created by the conductive layer formation method of this embodiment. In the electrostatic film actuator shown in Figure 10, the movable elements (g401, g403) and stators (g402, g404) are driven using a three-phase high-voltage AC wave (g411) so as to maintain the same phase. In the movable and stators, "1" represents the first phase, "2" represents the second phase, and "3" represents the third phase. In the electrostatic film actuator of Figure 10, the movable elements (g401, g403) move left and right relative to the plane of the paper by the AC wave. The stator and the movable element are arranged in parallel, for example, via an oil g405 and a rotatable ball gg406.

[0060] Figure 10 is a top view of the electrostatic film actuator. Image g450 is the This shows state 1. Image g460 shows state 2, where the mover g472 has moved to the right relative to the stator g471, as indicated by arrow g473.

[0061] Figure 12 is a schematic diagram showing the operation of Figure 11 from a side view. Image g500 shows an example of the state of the stator g541 and the moving element g542 before movement. The sine wave g551 represents the phase image of the stator g541. The sine wave g552 represents the phase image of the moving element g542. Image g510 shows an example of a state where the moving element g542 has begun to move to the right relative to the stator g541. Image g520 shows an example of the state where the moving element g542 has moved to its maximum extent to the right relative to the stator g541. Furthermore, after image g522, as shown in image g530, the moving element g542 moves to the left relative to the stator g541. In this way, the movement of the mobile unit is controlled by the AC wave, for example, to the left or right relative to the stator.

[0062] Figure 13 shows examples of the configuration and size of the electrostatic film actuators of the comparative example and this embodiment. In Figure 6, the longitudinal direction is the x-axis direction and the thickness direction is the z-axis direction. Image g600 shows a comparative example electrostatic film actuator, fabricated by etching. For example, the comparative example electrostatic film actuator has a distance of 200 μm between the centers of the electrode patterns in the x-axis direction, a distance of 70 μm between the electrode patterns in the z-axis direction, and a distance of 25 μm between the electrode patterns and the FPC film surface. Furthermore, under these conditions, the applied voltage required to increase thrust without damaging the film is, for example, 1500 V (1.5 kV), with a non-dielectric constant ε r It is 1.9. Image g610 shows the electrostatic film actuator of this embodiment, which was fabricated using the conductive layer formation method of this embodiment. In this embodiment, for example, the distance between the centers of the electrode patterns in the x-axis direction is 10 μm, the distance between the electrode patterns in the z-axis direction is 12 μm, and the distance between the electrode patterns and the FPC film surface is 5 μm. The required applied voltage is 650 V, and the non-dielectric constant is ε. r It is 2.6.

[0063] Here, the force f that acts when a voltage is applied is x The expression can be expressed as shown in equation (1), and the capacity C can be expressed as shown in equation (2).

[0064]

number

[0065]

number

[0066] In equations (1) and (2), p is the distance between the centers of the electrode patterns in the x-axis direction, d is the distance of the electrode patterns in the z-axis direction, V is the applied voltage, and S is the overlapping area of ​​the electrodes of the moving and stator.

[0067] According to equation (1), the thrust changes depending on the applied voltage V. Therefore, according to this embodiment, if the distance P between the centers is made smaller, the thrust increases accordingly, and the voltage V can be reduced. The electrostatic film actuator of this embodiment, created in this manner, achieves, for example, 1 / 10 the weight and size of the electrostatic film actuator of the comparative example, and reduces the mass to about 1 / 3 even when including peripheral equipment such as the power supply.

[0068] As described above, in this embodiment, instead of wet etching which removes material other than the necessary pattern area, the electrode pattern is formed using a metal nanoprinting method as one of the additive manufacturing methods which creates the necessary pattern area by layering. Furthermore, in this embodiment, nitrogen is sprayed during ink application to form a dummy pattern. Then, in this embodiment, an electrostatic film actuator equipped with the electrode pattern created in this way is manufactured.

[0069] Furthermore, in this embodiment, electrode patterns are formed by printing with metal nano-ink. While there are still challenges with metal nano-ink printing in terms of component formation, using it to form patterns in this way allows for a narrower pitch between patterns. In the case of electrostatic film actuators, there is no need to mount components, and since the wiring portion is formed, using the metal nano-ink printing method is suitable. In this embodiment, in addition to metal nanoprinting, gas injection during ink application and dummy patterns are also used to subdivide the spaces between patterns.

[0070] As a result, according to this embodiment, contact between patterns can be reduced by nitrogen injection and dummy patterns, enabling the creation of films with finer pitches (e.g., 10, 20 μm) that were not possible with conventional techniques. Consequently, according to this embodiment, the ratio of lines (patterns) to space can be improved to, for example, about 50% (conventionally, for example, about 10%), which was not possible with conventional techniques. Furthermore, according to this embodiment, an electrostatic film actuator equipped with the electrode pattern created in this way can be miniaturized and the applied voltage can be reduced. Moreover, according to this embodiment, since the actuator can be miniaturized, it is possible to make the actuator required for the same output thinner and smaller. In addition, according to this embodiment, the processes and man-hours involved in forming the electrode pattern can be significantly reduced compared to conventional methods.

[0071] <Second Embodiment> In the second embodiment, an example of a formation method using a wettability-changing layer (control layer) applied by polymer solution coating will be described.

[0072] [Example of a conductive layer forming apparatus configuration] Next, an example of the configuration of the conductive layer forming apparatus 1A will be described. Figure 14 shows an example of the configuration of a conductive layer forming apparatus according to this embodiment. As shown in Figure 14, the conductive layer forming apparatus 1A includes, for example, a control unit 11A and a storage unit 12. The control unit 11A includes, for example, an ultraviolet irradiation control unit 111 (high surface energy application unit), a bar drive control unit 112 (bar control unit), an ink coating control unit 113 (liquid application unit), a gas injection control unit 114 (gas injection unit), and a polymer solution coating control unit 115 (wettability change layer formation unit). The conductive layer forming apparatus 1A is connected, for example, to an ultraviolet irradiation device 2 (high surface energy application unit), a coating bar 3, an ink supply device 4 (liquid application unit), a gas injection device 5, and a polymer solution coating device 6 (wettability change layer forming unit).

[0073] The polymer solution coating apparatus 6 comprises a polymer solution 61 containing a polymer material selected from the group consisting of cycloolefin polymers, polylactic acid, dielectrics thereof, and porosilazanes. The polymer solution coating apparatus 6 coats the polymer solution in accordance with the control of the conductive layer forming apparatus 1. The polymer solution is an example of a material whose surface energy changes when energy (ultraviolet light) is applied.

[0074] The polymer solution coating control unit 115 controls the polymer solution coating apparatus 6, including the start and end of the coating process, the amount of coating, etc.

[0075] [How to create electrode patterns] Next, the method for creating the electrode pattern according to this embodiment will be explained using Figures 15 and 16. Figure 15 is a flowchart of the procedure for creating the electrode pattern according to this embodiment. Figure 16 is a diagram illustrating the procedure for creating the electrode pattern according to this embodiment. In this embodiment, the conductive layer formation is based on the silver nanoprinting method. In Figure 15, as indicated by the symbol g101, the printing direction is the x-axis direction, and the thickness direction of the FPC film is the z-axis direction. Note that the object on which the pattern is formed is not limited to the FPC film. Furthermore, as an example of a metal nanoink used to form an electrode pattern by coating the film, silver nanoink will be explained as an example.

[0076] (Step S101) As shown by the symbol g101 in Figure 15, the FPC film 301 on which the pattern is to be formed is set in the conductive layer forming apparatus 1A.

[0077] (Step S102) As shown by reference numeral g102 in Figure 15, the conductive layer forming apparatus 1A controls the polymer solution coating control unit 115 to coat the polymer solution onto the FPC film 301, and after coating, it is dried to form the wettability control layer 303.

[0078] (Step S103) As shown by reference numeral g103 in Figure 15, the conductive layer forming apparatus 1A forms a mask 302 on the portion of the wettability control layer 303 where a pattern is not to be formed.

[0079] (Step S104) As shown by the reference numeral g104 in Figure 15, the conductive layer forming apparatus 1A controls the ultraviolet irradiation device 2 and performs exposure by irradiating with ultraviolet light having a wavelength of, for example, 200 nm or less. As a result of this exposure, as shown by the reference numeral g105 in Figure 15, the pattern forming region 304 of the FPC film 301 that has been irradiated with ultraviolet light and is not covered by the mask 302 becomes polarized. Note that ink containing metal adheres more easily to the polarized areas.

[0080] (Step S105) As shown by reference numeral g106 in Figure 15, the conductive layer forming apparatus 1A controls the ink supply device 4 to apply ink 41 and controls the coating bar 3 to smooth the ink 41 in the x-axis direction. During this printing, the conductive layer forming apparatus 1A controls the gas injection device 5 to inject, for example, nitrogen 314. The direction and angle of nitrogen 314 injection will be described later. As shown by reference numeral g107 in Figure 15, as a result of smoothing the ink 41 with the coating bar 3 while injecting nitrogen 314, the ink 41 is applied only to the polarized pattern formation region. In this way, the conductive layer forming apparatus 1A prints ink 41 for forming an electrode pattern on the FPC film 301.

[0081] (Step S106) As shown by reference numeral g1108 in Figure 15, the conductive layer forming apparatus 1A controls the ultraviolet irradiation device 2 and irradiates ultraviolet light to cure the ink 41. As a result, as shown by reference numeral g109 in Figure 15, an electrode pattern 305 is formed at a desired position on the FPC film 301.

[0082] As described above, the conductive layer formation method of this embodiment (Figures 15 and 16) is applied by coating a polymer solution and then drying it to form a wettability control layer (control layer), so it can also be applied to polyimide films. Furthermore, in this embodiment as well, similar to the first embodiment, the number of steps and manufacturing costs for copper foil formation, resist coating, resist removal, etching, etc. can be significantly reduced compared to electrode patterns produced by general etching methods.

[0083] In the example above, silver nano-ink was used as an example of the metal ink to be applied, but it is not limited to this; the ink may be made of gold, copper, nickel, tin, platinum, palladium, etc. Furthermore, while the above example described the use of nitrogen spray during ink application, the sprayed gas is not limited to this; any gas that does not easily oxidize the metals contained in the ink and does not easily solidify is acceptable.

[0084] In the embodiments described above, examples were explained in which patterns created using this method are used in electrostatic actuators, but this is not the only way. It is also possible to use them as patterns for products. Furthermore, electrostatic actuators created in this way can be used, for example, in artificial muscles for robots and assistive devices.

[0085] Although embodiments for carrying out the present invention have been described above using examples, the present invention is not limited in any way to these embodiments, and various modifications and substitutions can be made without departing from the spirit of the present invention.

[0086] [Note] (Note 1) A first forming step of forming a wettability change layer on a substrate containing a material whose surface energy changes when energy (ultraviolet light) is applied, A second forming step involves imparting energy to the wettability change layer to form a high surface energy portion (polarized portion), A step of applying a liquid (ink) containing a conductive material (metal material) to the high surface energy portion, A coating step in which a coating bar that spreads the liquid containing the conductive material by moving it on the substrate is used to apply the liquid containing the conductive material onto the high surface energy portion, It has, A method for forming a conductive layer, wherein in the coating step, the liquid is coated while an oxygen-free gas is sprayed onto the liquid. (Note 2) (Note 1) A method for forming a conductive layer, wherein in the coating step, the gas is sprayed from the rear side relative to the direction of travel of the coating bar. (Note 3) A method for forming a conductive layer, in which, in the coating step, the gas is sprayed on the flat surface of the substrate at an angle with respect to the direction of travel of the coating bar, as described in (Appendix 1) or (Appendix 2). (Note 4) A method for forming a conductive layer, wherein in any one of (Note 1) to (Note 3), the gas is nitrogen. [Explanation of symbols]

[0087] 1...Conductive layer forming apparatus, 11...Control unit, 12...Storage unit, 111...Ultraviolet irradiation control unit, 112...Bar drive control unit, 113...Ink coating control unit, 114...Gas injection control unit, 2...Ultraviolet irradiation device, 3...Coating bar, 4...Ink supply device, 5...Gas injection device, 6...Polymer solution coating apparatus, 41...Ink, 51...Gas

Claims

1. A first forming step involves applying energy to the substrate to form a high surface energy area, A step of applying a liquid containing a conductive material to the high surface energy portion, A coating step in which a coating bar that spreads the liquid containing the conductive material by moving it on the substrate is used to apply the liquid containing the conductive material onto the high surface energy portion, It has, A method for forming a conductive layer, wherein the high surface energy portion provided on the substrate is divided into a main body portion and a dummy portion, and the dummy portion is positioned at least in either the front or rear direction relative to the main body portion in the direction of movement of the coating bar.

2. The dummy portion is positioned in a relative position to the front of the coating bar in the direction of movement, the main body, and the dummy portion is positioned to the rear of the coating bar in the direction of movement. The method for forming a conductive layer according to claim 1, wherein the coating step involves applying the liquid in the order of the front of the dummy portion, the main body portion, and the rear of the dummy portion.

3. The conductive layer forming method according to claim 2, wherein the rear portion of the dummy portion is wider in the direction of movement of the coating bar than the front portion of the dummy portion.

4. The conductive layer forming method according to claim 2 or claim 3, wherein the front portion and the rear portion of the dummy portion have grooves that are not high surface energy portions.

5. The conductive layer forming method according to claim 1 or claim 2, wherein the dummy portion is positioned at least on either the left or right side in the direction of movement of the coating bar relative to the main body.

6. The method for forming a conductive layer according to claim 1 or claim 2, wherein the coating step involves applying the liquid while spraying an oxygen-free gas at an angle to the vertical direction on the substrate and at an angle to the direction perpendicular to the direction of travel of the coating bar.

7. A method for forming a conductive layer according to claim 1 or 2, wherein a second forming step of forming a wettability change layer containing a material whose surface energy changes by the application of energy on the substrate is performed before the first forming step.

8. A high surface energy application unit that applies energy to the substrate to form a high surface energy area, A liquid application unit that applies a liquid containing a conductive material to the high surface energy portion, A bar control unit controls a coating bar that spreads the liquid containing the conductive material by moving on the substrate, Equipped with, The conductive layer forming apparatus comprises a high surface energy imparting section which is divided into a main body section and a dummy section, and the dummy section is formed at least in either the front or rear position relative to the main body section in the direction of movement of the coating bar.

9. The dummy portion is positioned in a relative position to the front of the coating bar in the direction of movement, the main body, and the dummy portion is positioned to the rear of the coating bar in the direction of movement. The conductive layer forming apparatus according to claim 8, wherein the bar control unit applies the liquid in the order of the front of the dummy part, the main body part, and the rear of the dummy part.

10. The conductive layer forming apparatus according to claim 9, wherein the rear of the dummy portion is wider in the direction of movement of the coating bar than the front of the dummy portion.

11. The conductive layer forming apparatus according to claim 9 or claim 10, wherein the front portion and the rear portion of the dummy portion have grooves that are not high surface energy portions.

12. The conductive layer forming apparatus according to claim 8 or 9, wherein the dummy portion is positioned at least on either the left or right side in the direction of movement of the coating bar relative to the main body.

13. The conductive layer forming apparatus according to claim 8 or 9, further comprising a gas injection unit that injects an oxygen-free gas at an angle with respect to the vertical direction on the substrate and at an angle with respect to the direction of travel of the coating bar when applying the liquid.

14. The conductive layer forming apparatus according to claim 8 or 9, further comprising a wettability change layer forming unit that forms a wettability change layer containing a material whose surface energy changes upon application of energy on the substrate.

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