Variable capacitor

Abstract

In one embodiment, a variable capacitor includes a first elongate member including a first conductive portion disposed toward a first distal end of the first elongate member and a second conductive portion disposed toward a second distal end of the first elongate member, the first elongate member is configured to pivot on a first fulcrum disposed between the first conductive portion and the second conductive portion, a first distance between the first fulcrum and a first conductive portion of the first elongate member is different from a second distance between the first fulcrum and a second conductive portion of the first elongate member; a second elongate member including a first conductive portion disposed toward a first distal end of the second elongate member and a second conductive portion disposed toward a second distal end of the second elongate member, where: one of the first elongate member and the second elongate member is a cathode; one of the first elongated member and the second elongated member is a cathode, and the other of the first elongated member and the second elongated member is an anode, the cathode and a respective first conductive portion of the anode forming a first capacitor, where a capacitance of the first capacitor is a function of a first pivot angle of the first elongated member on a first fulcrum, the capacitance of the second capacitor is a function of a first pivot angle of the first elongate member on the first fulcrum, the first conductive portion of the cathode and the second conductive portion of the anode are connected to a positive voltage of the first circuit, and the second conductive portion of the cathode and the second conductive portion of the anode are connected to a negative voltage of the second circuit. The first conductive portion and the second conductive portion of the anode are connected to a negative voltage of the first circuit such that the first capacitor and the second capacitor are connected in parallel. And wherein: the application of the potential difference by the first circuit results in pivoting of the first elongate member, a corresponding change in capacitance of the first capacitor proportional to the potential difference, and a corresponding change in capacitance of the second capacitor inversely proportional to the potential difference, and wherein the amplitudes of the capacitance changes of the first capacitor and the second capacitor are different, the sum of the capacitance of the first capacitor and the second capacitor varies with the potential difference.

Description

Technical Field

[0001] The present invention relates to a variable capacitor. Background Art

[0002] A variable capacitor is an electronic device whose capacitance can be changed by a controllable input. The controllable input can be a potential difference applied across the variable capacitor. A common form of potential-difference-controlled variable capacitor is the varactor diode, also known as a "varicap" or "varactor," which is typically based on a semiconductor with a reverse-biased pn junction.

[0003] Additive manufacturing (also known as three-dimensional (3D) printing) is the process of creating three-dimensional physical objects from a model, such as a digital model, through an additive process, in which material is laid down, adhered, bonded, or otherwise deposited in successive layers until the solid object is formed. This approach contrasts with traditional manufacturing techniques, in which objects are formed from an assembly of parts that can themselves be machined, cast, or molded. Additive manufacturing offers many advantages over traditional manufacturing techniques, both technical and commercial. Technically, additive manufacturing allows the creation of virtually any arrangement of three-dimensional objects from a growing range of materials, including plastics, metals, and ceramics. Because additive manufacturing methods are capable of producing complex structures, these arrangements can even include intricate internal features. Compared to traditional methods, additive methods generate less waste, offer increased consistency between manufactured items, increase manufacturing speed with minimal setup required from an initial design, and offer the advantages of novel structures and shapes, as well as new combinations of materials. Commercially, additive manufacturing offers significant cost savings over traditional manufacturing techniques, particularly when manufacturing relatively small quantities of items. For example, prototypes, proof of concepts, spare parts, and items manufactured in isolated or remote locations (such as in orbit or space) can be easily produced at low cost using additive manufacturing. Manufacturing speed is also beneficial because three-dimensional items can be produced relatively quickly from three-dimensional designs.

[0004] Potential difference controlled variable capacitors have not yet been manufactured using additive manufacturing processes. Therefore, there is a problem in that when an object requires a potential difference variable capacitor, additive manufacturing cannot be used to manufacture the object. Such an object must be manufactured in a component manner without a potential difference variable capacitor, and the potential difference variable capacitor (or an element with an integral variable capacitor) is manufactured separately, and the object is assembled by multi-component manufacturing. Potential difference variable capacitors can be manufactured using conventional semiconductor manufacturing processes, for example when using varactor diodes. Therefore, this problem reduces at least some of the above-mentioned benefits of additive manufacturing. Summary of the Invention

[0005] According to a first aspect of the present invention, a variable capacitor is provided, which includes: a first slender member, the first slender member including a first conductive portion arranged toward a first distal end of the first slender member and a second conductive portion arranged toward a second distal end of the first slender member, wherein the first slender member is configured to pivot on a first fulcrum arranged between the first conductive portion and the second conductive portion, wherein a first distance between the first fulcrum and the first conductive portion of the first slender member is different from a second distance between the first fulcrum and the second conductive portion of the first slender member; a second slender member, the second slender member including a first conductive portion arranged toward the first distal end of the second slender member and a second conductive portion arranged toward the second distal end of the second slender member, wherein: one of the first slender member and the second slender member is a cathode, and the other of the first slender member and the second slender member is an anode, and the corresponding first conductive portions of the cathode and the anode The cathode and the anode form a first capacitor, wherein the capacitance of the first capacitor is a function of the first pivot angle of the first slender member on the first fulcrum, and the corresponding second conductive parts of the cathode and the anode form a second capacitor, wherein the capacitance of the second capacitor is a function of the first pivot angle of the first slender member on the first fulcrum, the first conductive part and the second conductive part of the cathode are connected to the positive voltage of the first circuit, and the first conductive part and the second conductive part of the anode are connected to the negative voltage of the first circuit, so that the first capacitor and the second capacitor are connected in parallel, and wherein: the first circuit applies a potential difference resulting in the pivoting of the first slender member, a corresponding change in the capacitance of the first capacitor proportional to the potential difference, and a corresponding change in the capacitance of the second capacitor inversely proportional to the potential difference, wherein the amplitudes of the capacitance changes of the first capacitor and the second capacitor are different, so that the sum of the capacitances of the first capacitor and the second capacitor changes with the potential difference.

[0006] The application of a potential difference by the first circuit can cause pivoting of the first slender member, the pivoting being caused by the torque experienced by the first slender member in a first direction being greater than the torque experienced by the first slender member in a second direction, the torque experienced by the first slender member in the first direction being the product of the electrostatic attraction between the first conductive parts of the first capacitor and the first distance between the first fulcrum and the first conductive part of the first slender member, and the torque experienced by the first slender member in the second direction being the product of the electrostatic attraction between the second conductive parts of the second capacitor and the second distance between the first fulcrum and the first conductive part of the first slender member.

[0007] A first distance between the first fulcrum and the first conductive portion of the first elongated member may be greater than a second distance between the first fulcrum and the second conductive portion of the first elongated member such that a sum of the capacitances of the first and second capacitors is proportional to the potential difference.

[0008] The second distance between the first fulcrum and the second conductive part of the first slender member can be greater than the first distance between the first fulcrum and the first conductive part of the first slender member, and before the potential difference is applied, the first pivot angle of the first slender member can make the first spacing distance between the first conductive parts of the first capacitor smaller than the second spacing distance between the second conductive parts of the second capacitor, so that the sum of the capacitances of the first capacitor and the second capacitor is inversely proportional to the potential difference.

[0009] The second slender member can be configured to pivot on a second fulcrum disposed between the first conductive portion and the second conductive portion of the second slender member, wherein a first distance between the second fulcrum and the first conductive portion of the second slender member can be different from a second distance between the second fulcrum and the second conductive portion of the second slender member, wherein the capacitance of the first capacitor can be a function of a second pivot angle of the second slender member on the second fulcrum, and the capacitance of the second capacitor can be a function of the second pivot angle of the second slender member on the second fulcrum.

[0010] The potential difference applied by the first circuit can cause pivoting of the second slender member, and the pivoting is caused by the torque experienced by the second slender member in the second direction being greater than the torque experienced by the second slender member in the first direction, the torque experienced by the second slender member in the second direction being the product of the electrostatic attraction between the first conductive parts of the first capacitor and the first distance between the second fulcrum and the first conductive part of the second slender member, and the torque experienced by the second slender member in the first direction being the product of the electrostatic attraction between the second conductive parts of the second capacitor and the second distance between the second fulcrum and the second conductive part of the second slender member.

[0011] A first distance between the second fulcrum and the first conductive portion of the second elongated member may be greater than a second distance between the second fulcrum and the second conductive portion of the second elongated member.

[0012] A second distance between the second fulcrum and the second conductive portion of the second slender member may be greater than a first distance between the second fulcrum and the first conductive portion of the second slender member, and before the potential difference is applied, the second pivot angle of the second slender member may cause the first spacing distance between the first conductive portions of the first capacitor to be less than the second spacing distance between the second conductive portions of the second capacitor.

[0013] According to a second aspect of the present invention, there is provided an apparatus comprising the variable capacitor of the first aspect of the present invention.

[0014] According to a third aspect of the present invention, there is provided an additive manufacturing apparatus for manufacturing an article, the apparatus comprising: a computer system; a first additive manufacturing component, the first additive manufacturing component being suitable for forming a non-conductive three-dimensional structure; a second additive manufacturing component, the second additive manufacturing component being suitable for forming a conductive three-dimensional structure; wherein the first additive manufacturing component and the second additive manufacturing component can be operated under the control of the computer system, the computer system being suitable for controlling the components to form the variable capacitor of the first aspect of the present invention or the apparatus of the second aspect of the present invention.

[0015] According to a fourth aspect of the present invention, a computer system for controlling an additive manufacturing device is provided, wherein the additive manufacturing device is suitable for simultaneously manufacturing three-dimensional structures using non-conductive materials and conductive materials, and the computer system is operable to control the additive manufacturing device to form the variable capacitor of the first aspect of the present invention or the device of the second aspect of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order that the present invention may be better understood, embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0017] Figure 1 is a cross-sectional view of a first article having an integrated variable capacitor;

[0018] Figure 2 yes Figure 1 perspective drawing of an item;

[0019] Figure 3a is a cross-sectional view of a variable capacitor in a stationary state;

[0020] Figure 3b yes Figure 3a a cross-sectional view of a variable capacitor with an applied potential difference;

[0021] Figure 4a is a cross-sectional view of a variable capacitor in a stationary state;

[0022] Figure 4b yes Figure 4aa cross-sectional view of a variable capacitor with an applied potential difference;

[0023] Figure 5 is a block diagram of a computer system suitable for controlling the operation of an additive manufacturing machine; and

[0024] Figure 6 This is a diagram of components of an additive manufacturing device. DETAILED DESCRIPTION

[0025] Figure 1 A first article 100 is shown with an integrated variable capacitor 120. First article 100 is constructed using an additive manufacturing method, which includes one or more techniques, such as, among others: an extrusion deposition process; a material bonding process, such as selective laser sintering, direct metal laser sintering, selective laser melting, or electron beam melting; and / or a stereolithography method, such as photopolymerization. Such techniques are also referred to as three-dimensional (3D) printing, and the products or resulting articles of such techniques are referred to as 3D-printed articles or devices. First article 100 is composed of a physical structure 102, such as a body, frame, grid, arrangement, or other structure that substantially constitutes the article, otherwise referred to as the article's structure. For example, first article 100 can be, among others: a component; a prototype; an assembly; an appliance; a tool; a cover; a housing; a model; or any other conceivable three-dimensional article. Physical structure 102 is formed from a non-conductive material using an additive manufacturing process. For example, physical structure 102 is a plastic, such as a polymer.

[0026] First article 100 has formed variable capacitor 120 within physical structure 102, and variable capacitor 120 is integral with physical structure 102. Variable capacitor 120 is integral to the construction of first article 100 and is at least partially comprised of physical structure 102 of first article 100. Variable capacitor 120 is formed in a hole in physical structure 102 of first article 100. Most preferably, the hole formed for diode 120 is a sealed vacuum.

[0027] A cathode 106 is formed on one side of the hole. Cathode 106 is formed as an elongated member made of the same non-conductive material that forms solid structure 102. Cathode 106 is pivotally attached to solid structure 102 via cathode fulcrum 107. Cathode 106 includes a first arm and a second arm located on opposite sides of cathode fulcrum 107. The first arm of cathode 106 includes a first conductive portion 106a, and the second arm of cathode 106 includes a second conductive portion 106b. These first conductive portion 106a and second conductive portion 106b are formed by an additive manufacturing process, such as the technique described by Ladd et al. in "3D Printing of Free Standing Liquid Metal Microstructures" (Collin Ladd et al., Advanced Materials, Vol. 25, No. 36, pp. 5081-5085, September 25, 2013). Ladd et al. describe a method for extruding conductive metal wire at room temperature. This method is particularly suitable for combining with the extrusion of other materials (e.g., polymer extrusion). For example, the first conductive portion 106a and the second conductive portion 106b can be formed from a gallium alloy, such as a binary eutectic alloy of gallium and indium, which can be extruded at room temperature using an additive manufacturing process, as described by Ladd et al. Additionally or alternatively, the first conductive portion 106a and / or the second conductive portion 106b can be formed using a material bonding process such as sintering. For example, direct metal laser sintering can be used, in which a laser is used to precisely and selectively sinter metal powder.

[0028] Anode 108 is formed on the other side of the hole. Anode 108 is also formed as an elongated member composed of the same non-conductive material as that forming solid structure 102. Anode 108 is pivotally attached to solid structure 102 via anode fulcrum 109. Anode 108 includes a first arm and a second arm located on opposite sides of anode fulcrum 109. The first arm of anode 108 includes a first conductive portion 108a, and the second arm of anode 108 includes a second conductive portion 108b. These first conductive portion 108a and second conductive portion 108b are formed using the same additive manufacturing process as described above for cathode 106.

[0029] like Figure 1 As shown, the first arm and the second arm of the cathode 106 have unequal lengths, and the first arm and the second arm of the anode 108 have unequal lengths. The first arms of the cathode 106 and the anode 108 can have equal lengths (or substantially equal lengths), but this is not required. Similarly, the second arms of the cathode 106 and the anode 108 can have equal lengths (or substantially equal lengths), but this is not required.

[0030] Note the following regarding the pivot angles of cathode 106 relative to cathode pivot point 107 and anode 108 relative to anode pivot point 109. In this specification, a first pivot direction is defined as a clockwise direction, and a second pivot direction is defined as a counterclockwise direction. Cathode 106 can pivot in a clockwise direction relative to pivot point 107, such that the first arm of cathode 106 moves toward solid structure 102 and the second arm of cathode 106 moves away from solid structure 102, or in a counterclockwise direction, such that the first arm of cathode 106 moves away from solid structure 102 and the second arm of cathode 106 moves toward solid structure 102. Similarly, the anode 108 can be pivoted in a clockwise direction relative to the anode fulcrum 108 such that the first arm of the anode 108 moves away from the solid structure 102 and the second arm of the anode 108 moves toward the solid structure 102, or in a counterclockwise direction such that the first arm of the anode 108 moves toward the solid structure 102 and the second arm of the anode 108 moves away from the solid structure 102.

[0031] In addition, a friction torque is applied to cathode 106 by cathode fulcrum 107 to resist changes in the pivot angle due to the torque acting on cathode 106. In the absence of any other forces acting on cathode 106, cathode 106 is subject to a net gravitational torque, which is the difference between the torque due to gravity acting on its longer arm in one direction and the torque due to gravity acting on its shorter arm in the other direction. The friction torque of cathode fulcrum 107 is greater than the net gravitational torque, so that cathode 106 does not pivot at cathode fulcrum 107 due to the net gravitational torque alone. Therefore, cathode 106 can be manufactured to have a predetermined static pivot angle at cathode fulcrum 107 (i.e., the pivot angle of cathode 106 when cathode 106 is subject only to gravity). The friction torque of anode fulcrum 109 is similarly greater than the net gravitational torque experienced by anode 108, so that anode 108 can be manufactured to have a predetermined static pivot angle at anode fulcrum 109.

[0032] The first conductive portion 106a of the cathode 106 and the first conductive portion 108a of the anode 108 are formed in a manner facing each other. Similarly, the second conductive portion 106b of the cathode 106 and the second conductive portion 108b of the anode 108 are formed in a manner facing each other. Figure 2As more clearly shown in the perspective view of FIG1 (which shows only a portion of the solid structure 102 so that the features disposed within the pores are more apparent), each of the cathode 106 and the anode 108 is electrically connected to an electrically conductive electrical connection 112, 114. The electrical connections 112, 114 are adapted to apply an electrical potential difference between the first conductive portion 106a of the cathode 106 and the first conductive portion 108a of the anode 108, and between the second conductive portion 106b of the cathode 106 and the second conductive portion 108b of the anode 108. The electrical connection 112 of the cathode 106 is connected to a source of positive potential (e.g., a positive voltage), while the electrical connection 114 of the anode 108 is connected to a source of relatively small potential (e.g., ground). The electrical connections 112, 114 are formed as part of an additive manufacturing process (e.g., the method of Ladd et al. described above, or any suitable method for depositing the electrically conductive electrical connections by additive manufacturing while manufacturing the first article 100).

[0033] The first conductive portions 106a, 108a of the cathode 106 and anode 108 thus create a first capacitor having a first separation distance. This first separation distance, and therefore the capacitance of the first capacitor, can vary with the pivot angle of the cathode 106 and anode 108, respectively, on the cathode pivot point 107 and anode pivot point 109. Similarly, the second conductive portions 106b, 108b of the cathode 106 and anode 108 create a second capacitor having a second separation distance. This second separation distance, and therefore the capacitance of the second capacitor, can vary with the pivot angle of the cathode 106 and anode 108, respectively, on the cathode pivot point 107 and anode pivot point 109.

[0034] As described above, cathode 106 and anode 108 can both be manufactured to have predetermined stationary pivot angles at cathode pivot point 107 and anode pivot point 109, respectively. Since the first separation distance and the second separation distance are functions of the pivot angles, variable capacitor 120 can be manufactured to have a predetermined first separation distance and a predetermined second separation distance.

[0035] The pivoting of the cathode 106 and the anode 108 can be caused by applying a potential difference between the first conductive portions 106a, 106b of the first capacitor and between the second conductive portions 106b, 108b of the second capacitor, thereby causing electrostatic attraction between the first conductive portions 106a, 108a of the first capacitor and between the second conductive portions 106b, 108b of the second capacitor. These electrostatic attractions are on opposite sides of the cathode pivot 107 and on opposite sides of the anode pivot 109. Therefore, if the magnitude of the torque experienced by the cathode 106 in the counterclockwise direction due to the electrostatic attraction of the first conductive portions 106a, 108a of the first capacitor is different from the magnitude of the torque experienced by the cathode 106 in the clockwise direction due to the electrostatic attraction of the second conductive portions 106b, 108b of the second capacitor, the cathode 106 will experience a net torque. Similarly, if the magnitude of the torque experienced by the anode 108 in the clockwise direction due to the electrostatic attraction of the first conductive portions 106a, 108a of the first capacitor is different from the magnitude of the torque experienced by the anode 108 in the counterclockwise direction due to the electrostatic attraction of the second conductive portions 106b, 108b of the second capacitor, the anode 108 will experience a net torque.

[0036] In the remainder of this description, when a potential difference is applied, the cathode 106 and anode 108 experience a net torque that is greater than the friction torque of the cathode pivot 106 and anode pivot 108 , causing the cathode 106 and anode 108 to pivot.

[0037] The application of a potential difference thus causes a change in the first and second separation distances between the first and second capacitors. Furthermore, because the first and second arms of cathode 106 and anode 108 are unequal in length, the magnitude of the change in separation distance for capacitors farther from pivot points 107, 109 will be greater than the magnitude of the change in separation distance for capacitors closer to pivot points 107, 109 when a potential difference is applied. This, in turn, means that the magnitude of the change in capacitance for capacitors farther from pivot points 107, 109 will be greater than the magnitude of the change in capacitance for capacitors closer to pivot points 107, 109 when a potential difference is applied. The total capacitance of variable capacitor 120 is the sum of the capacitance of the first and second capacitors. Since the magnitude of the change in capacitance of one capacitor is greater than the magnitude of the change in capacitance of the other capacitor, there is a corresponding change in the total capacitance of variable capacitor 120 caused by the application of the potential difference. Furthermore, since the magnitude of the change in separation distance, and therefore capacitance, is a function of the applied potential difference, the total capacitance of variable capacitor 120 is a function of the applied potential difference.

[0038] The magnitude of the change in separation distance, and therefore capacitance, is also a function of the length of the first arm, the length of the second arm, the friction torque of the cathode fulcrum 107, and the friction torque of the anode fulcrum 109. Thus, the magnitude of the change in the total capacitance of the variable capacitor 120 as a function of the applied potential difference can be configured by manufacturing the article 100 with specific values for one or more of these characteristics.

[0039] The variable capacitor 120 can also be manufactured so that the total capacitance of the variable capacitor 120 is proportional or inversely proportional to the applied potential difference. This characteristic is determined by whether the capacitor farther from the support point increases its separation distance (resulting in an inversely proportional relationship) or decreases its separation distance (resulting in a proportional relationship) when the potential difference is applied. For illustrative purposes, the first and second examples will be described.

[0040] like Figure 3a As shown in the simplified diagram of FIG, a first example is a variable capacitor 220 having a cathode 206, an anode 208, a cathode pivot 207, and an anode pivot 209. The variable capacitor 220 is manufactured such that: the first arms of the cathode 206 and the anode 208 are longer than the second arms of the cathode 206 and the anode 208, such that the first capacitor is further away from the pivots 207 and 209 than the second capacitor, and at rest, the cathode 206 and the anode 208 are parallel. When a potential difference is applied, as shown in FIG. Figure 3b As shown, the torque experienced by cathode 206 in the counterclockwise direction due to the electrostatic attraction between conductive portions 206a, 208a of the first capacitor (which is farther from pivot points 207, 209) is greater than the torque experienced by cathode 206 in the clockwise direction due to the electrostatic attraction between conductive portions 206b, 208b of the second capacitor (which is closer to pivot points 207, 209), causing cathode 206 to rotate in the counterclockwise direction. Furthermore, the torque experienced by anode 208 in the clockwise direction due to the electrostatic attraction between conductive portions 206a, 208a of the first capacitor is greater than the torque experienced by anode 208 in the counterclockwise direction due to the electrostatic attraction between conductive portions 206b, 208b of the second capacitor, causing anode 208 to rotate in the clockwise direction. This causes the first capacitor to decrease its separation distance (and therefore increase its capacitance), and the second capacitor to increase its separation distance (and therefore decrease its capacitance). When the capacitance of the first capacitor increases more than the capacitance of the second capacitor decreases, the capacitance of the variable capacitor 220 increases in accordance with the applied potential difference. Thus, this first example illustrates a variable capacitor 220 having a total capacitance proportional to the applied potential difference.

[0041] like Figure 4aAs shown, the second example is a variable capacitor 320 having a cathode 306, an anode 308, a cathode fulcrum 307, and an anode fulcrum 309, the variable capacitor 320 being manufactured such that: the first arms of the cathode 306 and the anode 308 are longer than the second arms of the cathode 306 and the anode 308, such that the first capacitor is further away from the fulcrums 307, 309 than the second capacitor, and when at rest, the cathode 306 and the anode 308 are not parallel, such that the second separation distance of the second capacitor is less than the first separation distance of the first capacitor. Figure 4b As shown, when a potential difference is applied:

[0042] the torque experienced by cathode 306 in a clockwise direction due to the electrostatic attraction between conductive portions 306 b and 308 b of the second capacitor (equal to the electrostatic attraction between conductive portions 306 b and 308 b of the second capacitor multiplied by the length of the second arm of cathode 306) is greater than the torque experienced by cathode 306 in a counterclockwise direction due to the electrostatic attraction between conductive portions 306 a and 308 a of the first capacitor (equal to the electrostatic attraction between conductive portions 306 a and 308 a of the first capacitor multiplied by the length of the first arm of cathode 306), causing cathode 306 to rotate in a clockwise direction; and

[0043] The torque experienced by the anode 308 in the counterclockwise direction due to the electrostatic attraction between the conductive portions 306 b and 308 b of the second capacitor (equal to the electrostatic attraction between the conductive portions 306 b and 308 b of the second capacitor multiplied by the length of the second arm of the anode 306) is greater than the torque experienced by the anode 308 in the clockwise direction due to the electrostatic attraction between the conductive portions 306 a and 308 a of the first capacitor (equal to the electrostatic attraction between the conductive portions 306 a and 308 a of the first capacitor multiplied by the length of the first arm of the anode 308), causing the anode 308 to rotate in the counterclockwise direction.

[0044] This causes the second capacitor to decrease its separation distance (and therefore increase its capacitance), and the first capacitor to increase its separation distance (and therefore decrease its capacitance). When the magnitude of the decrease in capacitance of the first capacitor is greater than the magnitude of the increase in capacitance of the first capacitor, the capacitance of the variable capacitor 330 decreases in net accordance with the applied potential difference. Thus, this second example illustrates a variable capacitor 320 having a total capacitance that is inversely proportional to the applied potential difference.

[0045] Therefore, the relationship between the applied potential difference and the total capacitance of the variable capacitor is determined by the length of the first arm, the length of the second arm, the first separation distance, and the second separation distance, which are all set at the time of manufacture. Therefore, these properties can be configured such that:

[0046] The net torque experienced by the cathode and / or anode causes rotation of the cathode and / or anode, thereby increasing the separation distance of capacitors closer to the pivot point and decreasing the separation distance of capacitors further from the pivot point, such that the total capacitance is proportional to the applied potential difference; or

[0047] The net torque experienced by the cathode and / or anode causes rotation of the cathode and / or anode, thereby decreasing the separation distance of capacitors closer to the pivot point and increasing the separation distance of capacitors further from the pivot point, such that the total capacitance is inversely proportional to the applied potential difference.

[0048] Thus, a potential difference-controlled variable capacitor with a specific relationship between the applied potential difference and its total capacitance can be manufactured using 3D printing technology (as described in more detail below). Consequently, low-cost plastics and polymers (instead of ceramics) can be used in the additive manufacturing process because there is no risk of thermal degradation. The variable capacitor can also be implemented in a circuit by connecting to two electrical connections, mimicking existing variable capacitors based on reverse-biased semiconductors.

[0049] Thus, the benefits of 3D printing (discussed in the background section above) can be realized for potential difference controlled variable capacitors and any object that requires a potential difference controlled variable capacitor. In a telecommunications example, a reconfigurable smart surface (RIS) can be manufactured with a frame (e.g., constructed of a non-conductive material such as plastic or polymer) and a plurality of unit cells located on the frame. The plurality of unit cells can be manufactured such that each unit cell contains a variable capacitor as described above, and the electrical connections of each variable capacitor are connected to a central controller. The central controller can control the capacitance of each variable capacitor by controlling the potential difference applied to each variable capacitor, thereby changing the incident electromagnetic field (e.g., changing its phase) in a known manner.

[0050] Variable capacitors can be used in other applications, such as in variable-controlled oscillators, parametric amplifiers, frequency multipliers, phase-locked loops, and tuned circuits.

[0051] Figure 5 5 is a block diagram of a computer system suitable for controlling the operation of an additive manufacturing machine. A central processing unit (CPU) 502 is communicatively connected to a storage device 504 and an input / output (I / O) interface 506 via a data bus 508. The storage device 504 can be any read / write storage device, such as a random access memory (RAM) or a non-volatile storage device. Examples of non-volatile storage devices include disk or tape storage devices. The I / O interface 506 is an interface to a device for input or output of data, or for both input and output of data. Examples of I / O devices that can be connected to the I / O interface 506 include a keyboard, a mouse, a display (such as a monitor), and a network connection.

[0052] Figure 6 is a component diagram of an additive manufacturing apparatus 606. The additive manufacturing apparatus 606 is a combined apparatus that includes a conductive additive fabricator 608 for forming a three-dimensional structure with a conductive material and a non-conductive additive fabricator 610 for forming a three-dimensional structure with a non-conductive material. Fabricators 608 and 610 are arranged to operate on the same target article during manufacturing so that the article can undergo the manufacture of conductive content or non-conductive content or the manufacture of both. Those skilled in the art will understand that the two fabricators 608 and 610 can be combined or integrated into a single component that can operate in multiple modes that can accommodate conductive and non-conductive materials. The two fabricators 608 and 610 operate in a synchronous and / or simultaneous manner or in a hybrid of synchronous and simultaneous modes. For example, the conductive additive manufacturing process can be carried out in a manner that allows the non-conductive process to be carried out simultaneously, and then a simultaneous operating mode can be adopted (although not required). The operation of the fabricators 608 and 610 is preferably controlled by a computer. In Figure 6 In an embodiment, a computer system 612 is communicatively connected to a conductive additive manufacturer 608 and a non-conductive additive manufacturer 610 for instructing each of the manufacturers 608 and 610 regarding the additive manufacturing operations to be performed. The computer system 612 responds to a specification 604 for article manufacturing. In one embodiment, the specification 604 is a digital representation of the three-dimensional specifications of the article to be manufactured. For example, for an extrusion-based manufacturing process, the specification may include a definition of the material to be extruded and the location, position, arrangement or configuration of one or more extrusion heads, heads for adhesives, shapers, epoxies, etc. and / or worktables, workpieces or article holders. The manufacturing process can be defined using vector definitions that specify discrete or relative movement or repositioning, etc. Alternatively, in an additive manufacturing method based on particle fusion, the location of fusion, bonding, heating, etc. can be specified by the specification 604, for example, by control instructions for a laser or similar fusion mechanism. The specification 604 can be in the form of an additive manufacturing file format (AMF) or a stereolithography file format (STL).

[0053] Specifications 604 are provided by a specification definition system 602, such as a 3D modeling system, computer-aided design (CAD), or computer-aided manufacturing (CAM) system known in the art. Such a system may be adapted to generate specifications 604 in AMF or STL format. Such a format may be adapted to include additional information related to electronic circuit elements (such as active and passive components) and the electrical connections therebetween.

[0054] Although the variable capacitor has been described as being manufactured by an additive manufacturing process, those skilled in the art will understand that this is not required and that the variable capacitor (or an object requiring a variable capacitor) may be manufactured by other methods, such as by machining, casting, or molding some or all of the components.

[0055] The aperture of the variable capacitor can be vacuum-sealed. This can be achieved by manufacturing the article in a sealed atmosphere, so that there is no fluid communication in or out of the aperture during manufacturing, or by manufacturing channels and evacuation ports in the article and evacuating the aperture using a vacuum pump. This is beneficial when the variable capacitor is used in high-voltage or high-precision implementations. However, a vacuum is not required, so this feature is not essential. The aperture can alternatively contain air.

[0056] Those skilled in the art will appreciate that it is not necessary that both the cathode and the anode pivot relative to the solid structure. That is, one of the cathode and the anode may be fixed and may also be part of the solid structure.

[0057] Those skilled in the art will also understand that the technique for depositing the conductive material as described by Ladd et al. is not required and that other techniques may be used. For example, commercially available additive manufacturing printers (e.g., the DragonFly IV sold by Nano Dimension) can be used to manufacture articles having conductive portions.

[0058] A person skilled in the art will understand that any combination of features is possible within the scope of the claimed invention.

Claims

1. A variable capacitor, comprising: a first elongated member comprising a first conductive portion disposed toward a first distal end of the first elongated member and a second conductive portion disposed toward a second distal end of the first elongated member, wherein the first elongated member is configured to pivot on a first fulcrum disposed between the first conductive portion and the second conductive portion, wherein a first distance between the first fulcrum and the first conductive portion of the first elongated member is different from a second distance between the first fulcrum and the second conductive portion of the first elongated member; a second elongated member comprising a first conductive portion disposed toward a first distal end of the second elongated member and a second conductive portion disposed toward a second distal end of the second elongated member, in: one of the first elongated member and the second elongated member is a cathode, and the other of the first elongated member and the second elongated member is an anode, The respective first conductive portions of the cathode and the anode form a first capacitor, wherein the capacitance of the first capacitor is a function of a first pivot angle of the first elongated member on the first fulcrum, and the respective second conductive portions of the cathode and the anode form a second capacitor, wherein the capacitance of the second capacitor is a function of the first pivot angle of the first elongated member on the first fulcrum, the first conductive portion and the second conductive portion of the cathode being connected to a positive voltage of a first circuit, The first and second conductive portions of the anode are connected to a negative voltage of the first circuit such that the first capacitor and the second capacitor are connected in parallel, and wherein: The application of a potential difference by the first circuit causes pivoting of the first elongated member, a corresponding change in capacitance of the first capacitor that is proportional to the potential difference, and a corresponding change in capacitance of the second capacitor that is inversely proportional to the potential difference, wherein the magnitudes of the changes in capacitance of the first capacitor and the second capacitor are different such that the sum of the capacitances of the first capacitor and the second capacitor varies with the potential difference.

2. The variable capacitor according to claim 1, wherein The first circuit applies the potential difference to cause pivoting of the first slender member, and the pivoting is caused by the torque experienced by the first slender member in the first direction being greater than the torque experienced by the first slender member in the second direction, the torque experienced by the first slender member in the first direction being the product of the electrostatic attraction between the first conductive parts of the first capacitor and the first distance between the first fulcrum and the first conductive part of the first slender member, and the torque experienced by the first slender member in the second direction being the product of the electrostatic attraction between the second conductive parts of the second capacitor and the second distance between the first fulcrum and the second conductive part of the first slender member.

3. The variable capacitor according to claim 2, wherein The first distance between the first fulcrum and the first conductive portion of the first elongated member is greater than the second distance between the first fulcrum and the second conductive portion of the first elongated member, so that the sum of the capacitances of the first and second capacitors is proportional to the potential difference.

4. The variable capacitor according to claim 2, wherein The second distance between the first fulcrum and the second conductive part of the first slender member is greater than the first distance between the first fulcrum and the first conductive part of the first slender member, and before the potential difference is applied, the first pivot angle of the first slender member makes the first spacing distance between the first conductive parts of the first capacitors less than the second spacing distance between the second conductive parts of the second capacitors, so that the sum of the capacitances of the first capacitor and the second capacitor is inversely proportional to the potential difference.

5. A variable capacitor according to any one of the preceding claims, wherein The second slender member is configured to pivot on a second fulcrum disposed between a first conductive portion and a second conductive portion of the second slender member, wherein a first distance between the second fulcrum and the first conductive portion of the second slender member is different from a second distance between the second fulcrum and the second conductive portion of the second slender member, wherein the capacitance of the first capacitor is a function of a second pivot angle of the second slender member on the second fulcrum, and the capacitance of the second capacitor is a function of the second pivot angle of the second slender member on the second fulcrum.

6. The variable capacitor according to claim 5, wherein The application of the potential difference by the first circuit causes pivoting of the second slender member, the pivoting being caused by the torque experienced by the second slender member in the second direction being greater than the torque experienced by the second slender member in the first direction, the torque experienced by the second slender member in the second direction being the product of the electrostatic attraction between the first conductive parts of the first capacitor and the first distance between the second fulcrum and the first conductive part of the second slender member, and the torque experienced by the second slender member in the first direction being the product of the electrostatic attraction between the second conductive parts of the second capacitor and the second distance between the second fulcrum and the second conductive part of the second slender member.

7. The variable capacitor according to claim 6 when dependent on claim 3, wherein: A first distance between the second fulcrum and the first conductive portion of the second elongated member is greater than a second distance between the second fulcrum and the second conductive portion of the second elongated member.

8. The variable capacitor according to claim 6 when dependent on claim 4, wherein: A second distance between the second fulcrum and the second conductive portion of the second slender member is greater than a first distance between the second fulcrum and the first conductive portion of the second slender member, and before the potential difference is applied, a second pivot angle of the second slender member causes the first spacing distance between the first conductive portions of the first capacitor to be less than the second spacing distance between the second conductive portions of the second capacitor.

9. A device comprising a variable capacitor according to any preceding claim.

10. An additive manufacturing apparatus for manufacturing an article, the apparatus comprising: Computer systems; a first additively manufactured component adapted to form a non-conductive three-dimensional structure; a second additively manufactured component adapted to form an electrically conductive three-dimensional structure; Wherein the first additively manufactured component and the second additively manufactured component are operable under the control of the computer system, the computer system being adapted to control the components to form a variable capacitor or device according to any one of claims 1 to 9.

11. A computer system for controlling an additive manufacturing apparatus, the additive manufacturing apparatus being adapted to simultaneously manufacture a three-dimensional structure from a non-conductive material and a conductive material, the computer system being operable to control the additive manufacturing apparatus to form a variable capacitor or device according to any one of claims 1 to 9.

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