Droplet ejector assembly structure and method

Abstract

The droplet ejector assembly comprises a substrate equipped with a CMOS control circuit, a plurality of layers on a first surface of the substrate, a fluid chamber having a droplet ejection port, and a piezoelectric actuator element formed by one or more of the layers, defining a portion of the fluid chamber, and comprising a first electrode and a second electrode. At least one of the electrodes is electrically connected to the CMOS control circuit. The piezoelectric actuator element is separate from the droplet ejection port, and the piezoelectric body is formed of one or more piezoelectric materials that can be processed at temperatures below 450°C. [Effect] The CMOS control circuit is integrated with the droplet ejector assembly and can receive both analog actuator ejection pulses and serial digital control signals. The serial digital control signals can be used to determine which piezoelectric actuator elements are connected to and driven by individual actuator ejection pulses.

Description

[Technical Field]

[0001] This invention relates to an inkjet print head, an additive manufacturing print head, and a fluid distribution print head. A droplet ejector assembly using a piezoelectric actuator for applications such as a head. Regarding the field of yellowtail. [Background technology]

[0002] To maximize resolution, the piezoelectric inkjet printhead uses each nozzle A relatively high density, individually controllable system configured to selectively discharge liquid through it. We aim to provide an actuator. To provide the required resolution, we use commercially available high-density pressure An electric inkjet printhead is generally one or more droplet ejector assemblies. Equipped with a separate print head control circuit and capable of controlling multiple actuators, It has many electrical connections to one or more droplet ejector assemblies. For example, Fuji( High-density printing by Ricoh (registered trademark), Ricoh (registered trademark), or Epson (registered trademark) The printhead is currently connected to the film via many parallel electrical connections. Using head drive integrated circuits and flexible assemblies, individual units within the print head It drives several piezoelectric actuators.

[0003] To simplify manufacturing, improve configurability, and enhance reliability, inkjet Reducing the number of individual wired connections to the print head would be advantageous. This is achieved by integrating the control circuit embedded in the integrated circuit board with a piezoelectric actuator. This can be achieved. However, the CMOS drive circuit requires a (peak) temperature during manufacturing. This at least partially leads to the problem of incompatibility with industry-standard piezoelectric actuators. .

[0004] More specifically, piezoelectric actuators for inkjet print heads are currently, Generally, it is formed from lead zirconate titanate (PZT). PZT has the advantage of high piezoelectricity. It has a constant (>100). PZT is a temperature that would damage the CMOS device. Processing is required. For example, PZT can be deposited by physical vapor deposition, but this involves... Subsequently, an annealing step and / or a polling step at a temperature exceeding 450°C A neutron is required, or it can be deposited by the sol-gel method, but high-temperature anionization (above 600°C) is necessary. This involves a ringing step. It includes a reduction in dopant mobility and an interconnection wiring method, There are numerous problems associated with processing CMOS at high temperatures. CMOS electronics is 45 It is known to withstand temperatures of 0°C. To obtain a high yield, a considerably lower temperature (sun) A temperature of less than 300°C is preferable.

[0005] Deposition of PZT and other piezoelectric materials is often done to orient the crystals. Polling steps are also necessary, which fundamentally involve exposing the device to a very high electric field. The ring step is also not CMOS compatible.

[0006] Because lead is not permitted to be brought into CMOS manufacturing plants, PZT actuators It is impossible to manufacture a CMOS circuit and then subsequently manufacture an integrated CMOS circuit on top of it.

[0007] Therefore, PZT piezoelectric materials are not CMOS compatible and are not integrated with CMOS control circuits. cannot be formed. Alternative known piezoelectric materials have considerably lower piezoelectric constants, so PZT could not be replaced by alternative materials.

[0008] Accordingly, the present invention seeks to improve the integration of piezoelectric droplet ejector assemblies, and in some embodiments, seeks to improve the density of droplet ejectors within a print head.

[0009] WO2018 / 054917 (McAvoy) discloses that a substrate having a CMOS device proposes a droplet ejector assembly integrated with an actuator formed of a piezoelectric material that can be processed at a temperature below 450°C and is CMOS-compatible, wherein the substrate is integrated with a nozzle forming layer, and the piezoelectric actuator is located on a nozzle portion of the nozzle forming layer, which was only enabled by the novel design of the actuator. Such an actuator configuration has a different configuration from the typical arrangement where the nozzle is located on the wall of the fluid chamber on the opposite side of the actuator, and despite involving a reduction of at least one order of magnitude, and in some cases two orders of magnitude, in piezoelectric coefficient, it significantly improves droplet ejection efficiency compared to other device configurations, and enables the use of piezoelectric materials other than PZT. SUMMARY OF THE INVENTION

[0010] In a first aspect, the present invention provides a droplet ejector assembly for a print head, the droplet ejector assembly comprising: a substrate having a first surface and an opposing second surface, the substrate comprising a CMOS control circuit; a plurality of layers on the first surface of the substrate; a fluid chamber having a droplet discharge outlet; and a piezoelectric actuator element formed by one or more of said layers, comprising a piezoelectric body, a first electrode and a second electrode in contact with the piezoelectric body, wherein in use the piezoelectric actuator element deforms configurable), and the piezoelectric actuator element defines a portion (e.g., the wall ) of the fluid chamber.

[0011] Typically, at least one of said electrodes (and optionally, a first electrode and a second electro de) is electrically connected to a CMOS control circuit. The CMOS control circuit may compri se a CMOS actuator control circuit configured to control the actuator of the piezoelectric actuat or, or may be a CMOS actuator control circuit.

[0012] The piezoelectric body may be formed of one or more piezoelectric materials processable at a tempe rature lower than 450°C.

[0013] Typically, the piezoelectric actuator element is separate from the droplet discharge outlet. Surpr isingly, it has been found that an efficient droplet ejector assembly can be constructed using m aterials other than PZT without requiring a structure in which the droplet discharge outlet is a p ortion (typically an opening) of the piezoelectric actuator element.

[0014] Nevertheless, in some embodiments, the droplet discharge outlet may be part of the piezoelectric a ctuator element, or may be separate from the piezoelectric actuator element.

[0015] In a second aspect, the present invention provides an inkjet printer comprising: a controller; and one or more droplet ejector assemblies according to the first aspect, which are in electronic commu nication with the controller and controlled by the controller. The controller may be a print contr oller. The controller communicates with a memory storing program code , or one or more microcontrollers or memory, which may be integrated or distributed It may be equipped with a microprocessor. Inkjet printers have one or more further controls. - It can be equipped with.

[0016] In a third aspect, the present invention relates to a droplet ejector assembly according to the first aspect, or the The invention extends to a method for operating an inkjet printer according to the second embodiment, and a CMOS control circuit. However, (typically through at least one input from the controller) digital operation It receives a control signal, processes the digital operating control signal, and pressurizes to trigger droplet ejection. To selectively activate electric actuator elements.

[0017] Typically, CMOS control circuits are formed on the first surface of the substrate. The S control circuit includes at least one CMOS transistor on the first surface of the substrate. Typically, a CMOS control circuit can use a first electrode or without the need for further semiconductor junctions. At least one CMOS transistor is placed on the first surface of the substrate, which is electrically connected to the second electrode. Includes Ranjista.

[0018] When the temperature exceeds 300°C, typically, integrated electronic components (e.g., CMOS electronic components) Manufacturing quality begins to degrade, device operation is impaired, and efficiency decreases. Above 450°C Integrated electronic components (e.g., CMOS electronic components) typically degrade even more significantly. Therefore, by using a piezoelectric material that can be processed at temperatures below 450°C, Process the piezoelectric actuator without causing significant damage to the CMOS control circuit, and CMO This makes it possible to integrate it with the S control circuit.

[0019] The piezoelectric material comprises one or more piezoelectric materials that can be processed at temperatures below 300°C (for example, material (It may be formed from a material.) Piezoelectric materials that can be processed at temperatures below 300°C are used. This results in even less damage to the CMOS control circuit compared to processing at temperatures up to 450°C. This makes it possible to process piezoelectric actuators and integrate them with CMOS control circuits. By using piezoelectric materials that can be processed at temperatures below 00°C, it is possible to process on a single substrate (for example, a single Large-scale manufacturing of multiple fluid ejectors (from a single substrate wafer) enables more functional devices This makes it possible to achieve a high yield.

[0020] By integrating the piezoelectric actuator with the CMOS control circuit, a separate droplet ejection is achieved. Tadrive Electronics (typically, fluid / actuator / nozzle in existing devices) It is necessary to provide the piezoelectric print head assembly (which is provided as a separate component). The need for a large number of external connections is reduced or eliminated. This makes it easier to increase the number of nozzles per assembly, and the overall print head size It reduces noise and achieves higher printhead noise than is possible with existing piezoelectric printheads. This enables high density printing. Other advantages related to integration on a single printhead assembly. These include reduced manufacturing costs, modularity, and device reliability.

[0021] Piezoelectric materials that can be processed at temperatures below 450°C (or below 300°C) are typically processed at high temperatures. It has inferior piezoelectric properties (e.g., a lower piezoelectric constant) compared to the required piezoelectric material. For example, Piezoelectric action formed from high-temperature processable piezoelectric materials such as lead zirconate titanate (PZT) The tuner is formed from a low-temperature processable piezoelectric material such as aluminum nitride (AlN). It can apply a force that is more than an order of magnitude greater than that of a piezoelectric actuator, and all other factors They are equal.

[0022] Piezoelectric materials that can be processed at temperatures below 450°C (or below 300°C) are typically 450°C. It is a piezoelectric material that can be deposited at temperatures below 450°C (or below 300°C). Piezoelectric materials that can be processed at temperatures below 00°C are typically those that can be processed at temperatures above 450°C (or below 300°C). At the above temperature, no post-deposition treatment (such as post-deposition annealing) is required. Therefore, piezoelectric materials that can be processed at temperatures below 450°C (or below 300°C) are typically, At temperatures below 450°C (or below 300°C) (that is, to make a piezoelectric material into a piezoelectric state, (If annealing of the piezoelectric material is required), use an annealable piezoelectric material (after deposition) be.

[0023] One or more piezoelectric materials typically allow piezoelectric actuators to operate at temperatures below 450°C (or 300°C). To enable manufacturing at temperatures below 450°C (or below 300°C), processing is performed at temperatures below 450°C (or below 300°C). It is manageable (e.g., it can be deposited and, if necessary, annealed). Manufacturing of piezoelectric actuators at temperatures below 300°C is required. This enables the integration of the substrate and the CMOS control circuit, which is integrated with the substrate.

[0024] Therefore, piezoelectric materials typically operate at temperatures below 450°C (or below 300°C) (for example) (By deposition, and, if necessary, by annealing of one or more piezoelectric materials) It is possible to form it.

[0025] One or more piezoelectric materials are typically processed at substrate temperatures below 450°C (or below 300°C). It is manageable (for example, it can be deposited and, if necessary, annealed). In other words, The substrate temperature is typically affected by the processing of one or more piezoelectric materials (e.g., deposition, and as needed). During annealing, the temperature will not reach or exceed 450°C (or 300°C). The temperature of the plate typically reaches or exceeds 450°C (or 300°C) during the formation of the piezoelectric material. It will not happen. The substrate temperature is typically 450°C (or) during the manufacture of piezoelectric actuators. The temperature of the substrate will not reach or exceed 300°C. If the temperature does not reach or exceed 450°C (or 300°C) during the manufacturing process (for example, the whole process) There is.

[0026] Piezoelectric materials are typically deposited by one or more (e.g., low-temperature) physical vapor deposition (PVD) methods. It is possible (for example, by deposition). Piezoelectric materials are typically below 450°C (or, more preferably) At a temperature (i.e., substrate temperature) of less than 300°C, one or more (for example, It can be deposited by low-temperature physical vapor deposition (e.g., by being deposited).

[0027] The piezoelectric material comprises one or more (e.g., low-temperature) PVD-depositable piezoelectric materials (e.g., It may also be formed from one or more (e.g., low-temperature) PVD-deposited piezoelectric materials. It may also contain materials (for example, be formed from them).

[0028] Physical vapor deposition methods (e.g., low-temperature physical vapor deposition) may include one or more of the following vapor deposition methods. Cathode arc deposition, electron beam physical deposition, deposition, pulsed laser deposition, sputter deposition. Putter deposition is the sputtering of material from one or more sputtering targets. It may include.

[0029] One or more piezoelectric materials typically have a deposition temperature of less than 450°C (or less than 300°C). One or more piezoelectric materials have a PVD deposition temperature of less than 450°C (or less than 300°C). Possible. One or more piezoelectric materials may be subjected to sputtering temperatures below 450°C (or below 300°C). It may have a degree. One or more piezoelectric materials are subjected to post-deposition anodizing at temperatures below 450°C (or below 300°C). It may have a deposit temperature, PVD deposit temperature, sputtering temperature, or annealing temperature. The ring temperature is typically understood to be the temperature of the substrate during each processing step.

[0030] A piezoelectric material may include (for example, be formed from) one piezoelectric material. Alternatively, A piezoelectric material may comprise (for example, be formed from) two or more piezoelectric materials.

[0031] Piezoelectric materials typically have a capacitance of less than 30 pC / N, or more typically less than 20 pC / N, More typically, piezoelectric constant d has a magnitude of less than 10 pC / N. 31 To have. One The piezoelectric materials described above typically have a capacitance of less than 30 pC / N, or more typically less than 20 pC / N. , or more typically having a piezoelectric constant d of less than 10 pC / N 31 has .

[0032] One or more piezoelectric materials are typically CMOS compatible. The materials typically do not contain substances that damage the CMOS electronic structure, or typically do not contain such substances. , processable without using them (e.g., can be deposited and annealed if necessary) It will be understood that this is the case. For example, the processing of one or more piezoelectric materials (e.g., deposition) , and annealing as needed) is typically performed with (e.g., strong) acids (such as hydrochloric acid) and / Alternatively, (for example) strong alkalis (such as potassium hydroxide), or damage that can occur in CMOS factories. / Does not include the use of other materials that are not permitted.

[0033] Therefore, piezoelectric materials are not formed from PZT and typically do not contain PZT. This is a significant advantage because lead in T is harmful to the environment.

[0034] The piezoelectric material is aluminum and nitrogen, and optionally scandium and yttrium. Choose from titanium, magnesium, hafnium, zirconium, tin, chromium, and boron. It may include a ceramic material containing one or more elements (for example, formed therefrom) obtain).

[0035] Piezoelectric materials may contain (for example, be formed from) aluminum nitride (AlN). .

[0036] Piezoelectric materials may contain (or be formed from) zinc oxide (ZnO).

[0037] One or more piezoelectric materials may include aluminum nitride and / or zinc oxide (for example, (This could be the case.)

[0038] Aluminum nitride can consist of pure aluminum nitride. Alternatively, aluminum nitride Aluminum can contain one or more elements (i.e., aluminum nitride is aluminum nitride). (May contain compounds). Aluminum nitride may contain one or more of the following elements: Gadolinium, yttrium, titanium, magnesium, hafnium, zirconium, tin, chromium, boron.

[0039] The piezoelectric body may include scandium aluminum nitride (ScAlN) (for example, it may be formed therefrom). The proportion of scandium in scandium aluminum nitride is typically , selected in order to optimize the piezoelectric constant d 31 within the manufacturable range. For example, in Sc x A l 1-x N, the value of x is typically selected from the range of 0<x≤0.5. Typically , the greater the proportion of scandium, the larger the value of d 31 (i.e., a stronger piezoelec tric effect). The mass percentage (i.e., weight percentage) of scandium in scandium aluminum nitride is typically greater than 5%. The mass percentage (i.e., weight percentage) of scandium in scandium aluminum nitride is typically greater than 10%. The mass percentage (i.e., weight percentage) of scandium in scandium aluminum nitride is typically greater than 20%. The mass percentage (i.e., weight percentage) of scandium in scandium aluminum nitride is typically greater than 30%. The mass percentage (i.e., weight percentage) of scandium in scandium aluminum nitride is typically greater than 40%. The mass percentage (i.e., weight percentage) of scandium in scandium aluminum nitride may be 50% or less. The mass percentage (i.e., weight percentage) of scandium in scandium aluminum nitride may be 50% or less.

[0040] Aluminum nitride containing aluminum nitride compounds (and in particular scandium aluminum nitride), and zinc oxide are deposited at less than 450°C, or more preferably less than 300°C . It is a piezoelectric material that can be used. Aluminum nitride compounds (and especially aluminum scandi nitride) Aluminum nitride containing um, and zinc oxide, are used at temperatures below 450°C, or more preferably at temperatures below 450°C. Piezoelectric materials that can be deposited by physical vapor deposition (e.g., sputtering) at temperatures below 300°C. Aluminum nitride compounds (and especially aluminum scandium nitride) Luminium and zinc oxide are typically piezoelectric materials that do not require annealing after deposition. That is the case.

[0041] The piezoelectric material is deposited by physical deposition at a temperature of less than 450°C, or more preferably less than 300°C. The deposited aluminum nitride (aluminum nitride compounds, e.g., aluminum nitride scalar) It may contain (for example, be formed from) zinc oxide and / or zinc oxide.

[0042] The piezoelectric material consists of one or more III-V semiconductors and / or II-VI semiconductors (i.e., periodic Compound semiconductors containing elements from Group III and Group V, and / or Group II and Group VI of the table. It may include (for example, it may be formed from) such III-V semiconductors and II- VI semiconductors typically crystallize in a hexagonal wurtzite crystal structure. III-V and II-VI semiconductors that crystallize in a crystalline structure are typically not centrosymmetric. Due to its crystal structure, it is piezoelectric.

[0043] The piezoelectric material comprises one or more nonferroelectric piezoelectric materials (for example, formed from or ). It is possible that this could happen.

[0044] Each of the piezoelectric materials may be a non-ferroelectric piezoelectric material. Examples of non-ferroelectric piezoelectric materials This includes, for example, aluminum nitride, scandium aluminum nitride, and zinc oxide.

[0045] Conveniently, non-ferroelectric piezoelectric materials typically do not require poling. The manufacturing of ejector assemblies may not include polling.

[0046] Generally, non-ferroelectric piezoelectric materials do not have piezoelectric constants comparable in size to PZT. For example, ZnO, AlN, and ScAlN, which are non-ferroelectric piezoelectric materials, have a PZT of -10 to -2 For a value of 60, the piezoelectric constants d are -3.3, -1.9, and -5.8. 31 It holds.

[0047] The CMOS control circuit applies a potential gradient to the piezoelectric material in order to bend it in a first direction. Apply a voltage in direction 1, and then apply a voltage gradient to deform the piezoelectric body in the opposite direction (second direction). In some cases, the piezoelectric element is configured to be activated by applying an electric current in the opposite direction to the body. be.

[0048] The potential gradient is adjusted by changing the voltage applied to the first electrode and / or the second electrode. And it is applied. (One electrode may remain grounded, in which case the other electrode is not applied.) (Only the voltage being adjusted needs to be adjusted.)

[0049] To bend the piezoelectric material in a first direction, a potential gradient is applied to the piezoelectric material in a first direction, and then Next, to deform the piezoelectric material in the opposite, second direction, a potential gradient is applied to the piezoelectric material in the opposite direction. By doing so, the actuator can function as a push-pull actuator, and discharge Both the suction and distribution parts of the output cycle can be easily implemented. This allows for the strong operation of PZT and other similar technologies. This is impossible with dielectric materials.

[0050] Furthermore, greater deflection is possible from deformation in a first direction to deformation in another direction. This makes it possible to compensate for a reduced piezoelectric constant compared to ferroelectric materials such as PZT .

[0051] In a default configuration where no potential gradient is applied, the piezoelectric body is flat, and when bent in a first orientation and a second orientation respectively, the surface of the piezoelectric body closest to the fluid chamber may be respectively concave and convex, or vice versa.

[0052] Since the default flat configuration can extend the service life of the device, when no potential gradient is applied , it is advantageous to allow the piezoelectric body to be actuated into both a concave configuration and a convex configuration during an actuation cycle while remaining flat. This is in contrast to known push-pull piezoelectric actuators having ferroelectric piezoelectric bodies formed of PZT, which require a potential difference to be continuously applied to maintain the piezoelectric body in a deformed configuration between actuation cycles, or require a DC voltage for a predetermined period before starting an actuation cycle .

[0053] The piezoelectric body may have a relative permittivity ε r of less than 100.

[0054] This is in contrast to the case of using a piezoelectric body formed of PZT, which has a relative permittivity ε r far exceeding 100, and exceeding 1000 in some compositions. The capacitance between electrodes is a function of the relative permittivity ε r of the intervening dielectric (in the case of a parallel plate capacitor, it is proportional to said relative permittivity). The capacitance of the piezoelectric body affects the power consumption of each piezoelectric body, and corresponding piezoelectric bodies using PZT By using a material with a relatively low dielectric constant (compared to other devices), piezoelectric materials This enables reduced power consumption and / or higher nozzle density (using PZT). It has a relatively low capacitance (compared to the corresponding device).

[0055] Piezoelectric materials may have a dielectric breakdown voltage exceeding 100 V / μm.

[0056] By selecting a piezoelectric material with a dielectric breakdown voltage exceeding 100V / μm, approximately 50V / A larger operating force can be applied than in the case of PZT, which has a dielectric breakdown voltage of μm.

[0057] Typically, CMOS control circuits create potential gradients exceeding 100 V / μm within a piezoelectric material (for example, Depending on the structure, it is configured to apply the voltage to both sides. CMOS control circuits use 100V A potential gradient greater than / μm is applied to the piezoelectric body (for example, on both sides depending on the structure) in a first direction. Next, a potential gradient exceeding 100 V / μm is applied to the piezoelectric body (for example, on both sides depending on the structure). It can be configured to be applied in opposite directions.

[0058] This method involves creating a potential gradient of over 100 V / μm within the piezoelectric material (for example, on both sides depending on the structure). The method may include applying a potential to the first electrode and the second electrode in order to generate the product. This involves applying a potential gradient of over 100 V / μm to the piezoelectric body (for example, on both sides depending on the structure) to the first Generated in a direction, and then a potential gradient of over 100V / μm is applied to the piezoelectric body (for example, by structure) To generate in opposite directions (on both sides), apply potential to the first and second electrodes. It may include.

[0059] By using piezoelectric materials with a dielectric breakdown voltage exceeding 100V / μm, compared to PZT... This allows the reduced actuator force to be offset.

[0060] CMOS control circuits may (a) include digital registers. CMOS control The circuit may also include (b) a nozzle trimming calculation circuit and / or registers. The CMOS control circuit may also include (c) a temperature measurement circuit. (d) A fluid chamber filling detection circuit may also be provided.

[0061] A digital register may be, for example, a shift register or a latch register. The law stipulates storing data in a register within a CMOS control circuit, or retrieving data from a register. This may include reading the temperature. This method uses the temperature sensing component of a CMOS measurement circuit. This method may include measuring the temperature. This method measures the filling level of the fluid chamber. It may include.

[0062] A CMOS control circuit stores data, or typically, In response to measurements from one or more sensors located within the droplet ejector assembly, one or more It is configured to correct the voltage pulse applied to one or more electrodes of the piezoelectric actuator. It is possible that this is the case. This method uses data stored in a CMOS control circuit, or typical data. Specifically, in response to measurements from one or more sensors located within the droplet ejector assembly, A CM modifies the voltage pulse applied to one or more electrodes of more piezoelectric actuators. It may include an OS control circuit.

[0063] Modifying voltage pulses may involve shifting them in time. Modifying the pulses may include compressing or decompressing them. This may include correcting their magnitudes. Correcting voltage pulses is different. Multiple (typically,) of the received actuator drive pulses having a profile. This may include swapping between sequences (repeating). CMOS control circuits are typically C Data about individual piezoelectric actuators stored by the MOS control circuit, or one In response to the measurements from the above sensors, one or more of the individual piezoelectric actuators The method is configured to correct the voltage pulse applied to the electrodes, and typically, it is configured to correct the voltage pulse applied to the electrodes. This includes correcting the voltage pulse.

[0064] A CMOS control circuit may also include an ejection transistor. Typically, the electrodes of a piezoelectric actuator are electrically connected directly (with a switchable semiconductor junction interposed). (Without doing so) it communicates. This method controls the output transistor and the output transistor This may include applying these potential outputs directly to the electrodes of a piezoelectric actuator.

[0065] The droplet ejector assembly comprises multiple fluid chambers, each having a droplet outlet. and a plurality of piezoelectric acts formed by one or more layers on the first surface of the substrate It may also include a piezoelectric element, and each piezoelectric actuator may have a piezoelectric body and contact with the piezoelectric body. It comprises a first electrode and a second electrode, and each piezoelectric actuator element controls the respective fluid A portion of the chamber is defined. Therefore, the droplet ejector assembly can be operated independently. Furthermore, it may be equipped with multiple droplet ejectors. Typically, a CMOS control circuit may have multiple piezoelectric actors. The tuner element is controlled. In this case as well, each droplet outlet is controlled by the piezoelectric actuator element. They may be separate. Each fluid chamber, piezoelectric actuator element, and piezoelectric body are specified herein. It may be as described.

[0066] The droplet ejector assembly receives an electrical input to receive actuator drive pulses. It may be equipped. This method includes the step of receiving an actuator drive pulse. obtain.

[0067] The controller is configured to generate (typically a series of) actuator drive pulses. They may be equipped with a pulse generator. Droplet ejector assemblies are typically It includes an electrical input connected to a controller that receives actuator drive pulses. This method generates actuator drive pulses (for example, in a controller) and connects the electrical connections. This may include the step of conducting them to the droplet ejector assembly.

[0068] Actuator drive pulses are typically analog signals. A RUSS typically involves a periodic, repeating voltage waveform.

[0069] The CMOS control circuit controls one of the piezoelectric actuators or each of the piezoelectric actuators among the multiple piezoelectric actuators. At least one electrode of the electric actuator is connected to the received actuator drive pulse. The piezoelectric actuator can be selectively activated by switching between connecting and disconnecting it. In some cases, the system is configured to use a piezoelectric actuator among multiple piezoelectric actuators. The actuator or at least one electrode of each piezoelectric actuator is connected to the received actuator. The diode drive pulse is switched on or off, thereby controlling the piezoelectric actuator This may include selectively activating the data.

[0070] The controller generates one or more sequences of actuator drive pulses. Equipped with a pulse generator, the electrical input of the droplet ejector assembly is multiple to the controller. Through the electrical connection, the actuator is driven (by pulses generated by one or more pulse generators). Upon receiving multiple sequences of dynamic pulses, the CMOS control circuit controls multiple piezoelectric actuators. A plurality of piezoelectric actuators or at least one electrode of each piezoelectric actuator Selected from the received actuator pulses of different sequences If the tuner drive pulse is configured to be switchably connected or disconnected This method involves multiple different sequences of actuator drive pulses (for example, (At the controller) they are generated and then connected to the droplet ejector assembly via a separate electrical connection. Conduction, and one of the piezoelectric actuators or each piezoelectric actuator among multiple piezoelectric actuators At least one electrode of the tuner is connected to multiple different sequences of actuator drive parts. One or more received pulses from the variable (and selectable) pulses of the pulses The culverter drive pulse may include switching between connecting and disconnecting. ru.

[0071] Receiving an actuator pulse to which at least one electrode of the piezoelectric actuator is connected. The selection regarding the sequence is based on the stored data specific to each piezoelectric actuator. It can respond to the data and / or to the measured operation of each piezoelectric actuator. Therefore, a CMOS control circuit typically uses each piezoelectric actuator in a series of periodic cycles. At each of the typical droplet ejection decision points, it is possible to select whether or not to eject a droplet, and this method allows for this selection. Typically, each piezoelectric actuator ejects a droplet at each of a series of periodic droplet ejection decision points. This includes choosing whether or not to do so. The decision point is that for a particular piezoelectric actuator, at least It is determined whether or not to transmit an actuator drive pulse to the other electrode. This refers to the time before the start of the tuner drive pulse. In some embodiments, the CMOS control cycle The path is selected from among multiple actuator pulses (the same stream of actuator pulses, (or from different streams) Which actuator pulse is at each droplet ejection decision point This allows you to select whether the current is applied to at least one electrode of each piezoelectric actuator. This method can also be used, and typically involves selecting from among multiple actuator pulses (actuator Which actuator pulses (from the same stream of pulses or different streams) At the droplet ejection determination point, at least one electrode of each piezoelectric actuator This includes selecting whether or not to apply it.

[0072] Typically, actuator drive pulses repeat periodically. This may be amplified by the controller. The actuator drive pulse is transmitted to the droplet. The droplet ejector assembly may not amplify the droplet. In some cases, the cutter drive pulse may not be generated.

[0073] Typically, pulses from a pulse generator are part of a multi-droplet ejector assembly. It can be conducted to multiple control circuits. Therefore, a single pulse generator circuit can be transmitted to the same base. Multiple piezoelectric transducers on a plate, and / or each of multiple piezoelectric transducers It can drive multiple droplet ejector assemblies having separate substrates having a sac.

[0074] Digital operating control signals are typically received from a controller. The signal is typically received through a flexible connector. Digital control signals are It can be received in serial mode, and a shift register in the CMOS control circuit is used to process it in parallel. It can be converted into a control signal.

[0075] The controller is a droplet ejector assembly (or multiple droplet ejector assemblies) The actuator drive pulses are transmitted to the droplet ejector assembly (or multiple Configured to generate digital control signals that are transmitted to a number of droplet ejector assemblies. Equipped with a pulse generator, the digital control signal is a CMOS droplet ejector assembly. The control circuit processes which actuator drive pulses trigger droplet ejection. , the piezoelectric actuator of one or more droplet ejector assemblies, or multiple piezoelectric actuators In some cases, it may be necessary to determine whether conduction occurs to at least one electrode of the diode.

[0076] This method uses actuator drive pulses (e.g., in a controller) and digital control signals. The process involves generating a signal and controlling both the actuator drive pulse and the digital control signal with respect to the droplet. This includes conducting current to the CMOS control circuit of the ejector assembly, and the CMOS control circuit is To process digital control signals and, in response to them, trigger droplet ejection, The selected actuator drive pulse is transmitted to the piezoelectric actuator of one or more droplet ejector assemblies. It can conduct to at least one electrode of a cutter or a plurality of piezoelectric actuators.

[0077] Therefore, typically, analog actuator drive pulses and digital control signals are, Input by a CMOS control circuit (and typically by a droplet ejector assembly) Typically, digital control signals are used to select analog actuator drive pulses. The signals are selectively switched, thereby selectively transmitting them to the piezoelectric actuator.

[0078] This allows for the management of increased voltage, and piezoelectric materials other than PZT, and / or non This compensates for the limitations of ferromagnetic piezoelectric materials.

[0079] In some embodiments, the CMOS control circuit is configured to be connected in a switchable manner. This method requires grounding and a single fixed non-zero voltage line, or different lines, to cause droplet ejection. One of several fixed voltage lines of a certain voltage (one or more of which may be grounded) The above includes connecting to one or both electrodes of the piezoelectric actuator in a switchable manner. It is possible. For example, the CMOS control circuit can be switched, and this method causes droplet ejection. Between the connection to ground and the connection to a fixed voltage line, or to multiple fixed voltage lines of different voltages This may include switching the electrodes and then returning them to ground.

[0080] Switching electrodes between the connection to ground and the connection to a fixed voltage line, or between fixed voltage lines. This may include operating the latch.

[0081] The CMOS control circuit is formed by one or more such layers on the same substrate, and (different Each of the fluid chambers has a different droplet discharge port, defining a portion of each. At least three (or at least four) of the piezoelectric actuator elements can be individually and selectively It is configured to operate in such a way that at least three (or fewer) of the following can be optionally operated. At least four actuator elements are used to dispense fluids of different colors or compositions. Alternatively, it may be configured as a redundant droplet discharge port.

[0082] The at least three (or at least four) actuator elements are placed on the substrate. The CMOS control circuits are positioned (arbitrarily adjacent to each other and arbitrarily in a line), and one or more Connected to a flexible printhead cable having an electrical signal conductor above, CMOS control Your circuit responds to an operating command received through the same signal conductor with at least three ( Alternatively, the actuator elements of at least four actuator elements may be individually and It may be configured to operate selectively.

[0083] Therefore, at least three (or at least four) actuator elements are driven. By integrating the CMOS control circuit configured in this way, each signal conductor is at least 3 The operation of each actuator element of one (or at least four) piezoelectric actuator elements It can transmit control signals that lead to motion. Typically, these control signals are digital control signals. .

[0084] At least three (or at least four) piezoelectric actuator elements are used. A group of diverter elements that, for example, discharge fluids of the same color or composition (for example) (For example, having a fluid chamber that communicates with the same fluid supply, or different colors or combinations) Discharging a fluid (for example, having a fluid chamber that communicates with a separate fluid supply) A group or a number of piezoelectric actuator elements configured in such a manner (typically, at least Piezoelectric actuator elements are divided into three or at least four subgroups. The group may include, or may be, a group, and each subgroup has a piezoelectric actuator. The element discharges a fluid of the same color or composition (for example, the same fluid supply and fluid communication). A subgroup of piezoelectric actuators (with a chamber) that are configured to have a chamber, and some or all of them The element discharges fluids of different colors or compositions (for example, in fluid communication with a separate fluid supply). It is configured in such a way. Piezoelectric actuator elements of the same subgroup are arranged in an array. Therefore, multiple arrays can exist for each subgroup.

[0085] The CMOS control circuit is less than the signal conductor that receives the operation control signal. The configuration should allow for the individual and selective operation of at least twice the number of piezoelectric actuator elements. In some cases, this may be the case.

[0086] The CMOS control circuit has at least 128 (or at least 256) piezoelectric elements. The cutter elements are configured to operate individually and selectively, and the CMOS control circuit is The system receives operational control signals through up to 32 (or up to 16) signal conductors. There is a match.

[0087] The CMOS control circuit receives digital data in serial form through one or more signal conductors. A piezoelectric actuator is operated to simultaneously (i.e., in parallel) perform droplet ejection using the signal. It may include a serial-to-parallel conversion circuit configured to convert to a converter selection. A serial-to-parallel conversion circuit typically includes one or more shift registers.

[0088] The droplet ejector assembly is in contact with one or more of the layers and is different A system for supplying a liquid fluid of a certain color or composition to different fluid chambers, with at least three The system may further include a fluid supply block that defines a separate fluid supply manifold.

[0089] A fluid supply manifold is used to supply fluid of the same composition to each of multiple fluid chambers. , comprising a fluid conduit connected to each of the multiple fluid chambers, A piezoelectric actuator element defining a part of these is typically controlled by a CMOS control circuit. It may be activated in response to an activation command received through the signal conductor.

[0090] A droplet ejector assembly is typically a droplet ejector assembly for drop-on-demand applications. It is a component, for example, part of a drop-on-demand printhead.

[0091] The present invention comprises multiple droplet ejector assemblies driven from a common controller. This extends even to the print head (for example, the page-width print head).

[0092] In a fourth aspect, the present invention relates to a print head according to the first or second aspect of the present invention. The invention extends to a method for manufacturing a droplet ejector assembly for use, the method comprising a first surface To provide a substrate, to form a CMOS control circuit on the first surface, and the first surface The method includes forming multiple layers on a surface, wherein the multiple layers include a first electrode and a second electrode, It comprises a piezoelectric actuator element, which includes a piezoelectric material.

[0093] The steps of forming a piezoelectric actuator typically involve forming a first electrode, At temperatures below 450°C, at least one layer of piezoelectric material is placed on the first electrode. To form a second electrode on at least one layer of one or more piezoelectric materials. This includes the step of forming a first electrode and the step of forming a second electrode. Typically, it is performed at temperatures below 450°C. Typically, each of one or more layers is 45 It is formed at temperatures below 0°C. Therefore, piezoelectric actuators are formed at temperatures below 450°C. To form (for example, to form a first electrode, one or more piezoelectric materials, and a second electrode) This allows for, without significant damage to at least one electronic component (for example, a drive circuit), It becomes possible to integrate the piezoelectric actuator with the at least one electronic component. ru.

[0094] This method may include forming a piezoelectric actuator at a temperature below 300°C. The step of forming the piezoelectric actuator is to form the first electrode and to heat it at 300°C. At full temperature, at least one layer of piezoelectric material is formed on the first electrode. The method involves forming a second electrode on at least one layer of one or more piezoelectric materials, This may include the steps of forming the first electrode and forming the second electrode, and also the 3 It can be run at temperatures below 00°C.

[0095] Form a piezoelectric actuator at a temperature below 300°C (e.g., one or more first electrodes). By forming a piezoelectric material and a second electrode, damage to the CMOS control circuit is further reduced. By reducing the number of components, it becomes possible to integrate the piezoelectric actuator with the CMOS control circuit.

[0096] This method typically involves piezoelectric actuators at substrate temperatures below 450°C (or below 300°C). This includes forming a piezoelectric actuator. In other words, the temperature of the substrate while forming the piezoelectric actuator. Typically, it will not reach or exceed 450°C (or 300°C). Therefore, pressure The steps of forming an electric actuator typically involve forming a first electrode and 45 At a substrate temperature below 0°C (or below 300°C), one or more piezoelectric materials are placed on the first electrode. To form at least one layer of and on at least one layer of one or more piezoelectric materials The steps include forming a second electrode. The forming step is also typically performed at a substrate temperature of less than 450°C (or less than 300°C). The substrate temperature is controlled during the manufacturing of the droplet ejector assembly (e.g., the whole assembly). The temperature may reach or not exceed 450°C (or 300°C).

[0097] The step of forming all of one or more layers is performed at a temperature below 450°C (or more typically 30°C). It may be run at temperatures below 0°C.

[0098] Piezoelectric actuators are formed at temperatures below 450°C (or, more typically, below 300°C). The steps involve using a piezoelectric atom at a temperature of less than 450°C (or, more typically, less than 300°C). This may also involve the deposition of cutuators. Below 450°C (or, more typically, The step of forming a piezoelectric actuator at a temperature of less than 300°C is less than 450°C (or More typically, by one or more physical vapor deposition methods at temperatures below 300°C, piezoelectric This may also include the deposition of actuators.

[0099] Physical vapor deposition (e.g., low-temperature physical vapor deposition) typically involves one or more of the following vapor deposition methods. Includes: Cathode arc deposition, electron beam physical deposition, deposition, pulsed laser deposition, sputter deposition. Sputter deposition is a process in which a material is sputtered from a single or multiple sputtering targets. It may include ng.

[0100] The step of forming the piezoelectric material is performed at a temperature of less than 450°C (or, more typically, less than 300°C). The method may also include depositing at least one layer of one or more piezoelectric materials at a given temperature. It is possible. The step of forming the piezoelectric material is performed at a temperature of less than 450°C (or, more typically, less than 300°C). At a temperature of ____, at least one layer of one or more piezoelectric materials is deposited by physical vapor deposition. This may also include deposition.

[0101] This method uses piezoelectricity at temperatures below 450°C (or more typically, below 300°C). This may include performing any post-deposition treatment on the body. This method is suitable for temperatures below 450°C (or higher). Typically, this may include annealing a piezoelectric material at a temperature (below 300°C). However, more typically, this method involves post-deposition treatment (e.g., annealing) steps. Does not include pu.

[0102] The step of forming a piezoelectric actuator involves aluminum and nitrogen, and optionally Specifically, scandium, yttrium, titanium, magnesium, hafnium, zirconium From ceramic materials containing one or more elements selected from tin, chromium, and boron, This may include forming a piezoelectric material.

[0103] The step of forming a piezoelectric body involves forming at least one layer, or two or more layers, of a piezoelectric material. This may include forming a layer of piezoelectric material.

[0104] The step of forming at least one layer of one or more piezoelectric materials is said to be the one or more piezoelectric materials It may consist of forming one layer of material. Alternatively, at least one or more piezoelectric materials The step of forming another layer involves forming two or more layers of the one or more piezoelectric materials. It can consist of these.

[0105] One or more piezoelectric materials may include aluminum nitride. Additionally or alternatively, one or more The piezoelectric material above may contain zinc oxide. The piezoelectric actuator should be operated at temperatures below 450°C (or higher). Typically, the step of forming at a temperature of less than 300°C (for example, less than 450°C (or, Typically, at temperatures below 300°C, at least one layer of one or more piezoelectric materials The step of forming the mixture is performed at a temperature of less than 450°C (or, more typically, less than 300°C). In this process, aluminum nitride (AlN) and / or zinc oxide (ZnO) are deposited. It may include it.

[0106] Aluminum nitride can consist of pure aluminum nitride. Alternatively, aluminum nitride Aluminum can contain one or more elements (i.e., aluminum nitride is aluminum nitride). (May contain compounds). Aluminum nitride may contain one or more of the following elements: Candium, yttrium, titanium, magnesium, hafnium, zirconium, tin, Chromium, boron.

[0107] forming a piezoelectric actuator at a temperature below 450°C (or more typically below 300°C) step (for example, forming at least one layer of one or more piezoelectric materials at a temperature below 450°C (or more typically below 300°C)) may comprise depositing scandium aluminum nitride (ScAlN) at a temperature below 450°C (or more typically below 300°C).

[0108] The proportion of scandium in scandium aluminum nitride is typically selected within a manufacturable range to optimize the piezoelectric constant d 31 . For example, for Sc x Al 1-x N, the value of x is typically selected from the range 0 < x ≦ 0.5. Typically, the higher the proportion of scandium , the larger the value of d 31 (i.e., the stronger the piezoelectric effect). The mass percentage (i.e., weight percentage) of scandium in scandium aluminum nitride is typically more than 5%. The mass percentage (i.e., weight percentage) of scandium in scandium aluminum nitride is typically more than 10%. The mass percentage (i.e., weight percentage) of scandium in scandium aluminum nitride is typically more than 20%. The mass percentage (i.e., weight percentage) of scandium in scandium aluminum nitride is typically more than 30%. The mass percentage of scandium in scandium aluminum nitride (i.e., weight percentage) is typically more than 40%. The mass percentage (i.e., weight percentage) of scandium in scandium alumi num nitride is 50% or less ​obtain.

[0109] One or more piezoelectric materials are one or more III-V semiconductors and / or II-VI semiconductors ( That is, chemicals containing elements of Group III and Group V of the periodic table, and / or Group II and Group VI. It may also include composite semiconductors. Such III-V and II-VI semiconductors. It typically crystallizes in a hexagonal wurtzite crystal structure. Crystallized III-V and II-VI semiconductors typically have a non-centrosymmetric crystal structure. Therefore, it is piezoelectric. Consequently, the piezoelectric actuator is suitable for temperatures below 450°C (or more accurately, In terms of type, the step of forming at a temperature of less than 300°C (for example, less than 450°C (or more Typically, the step of forming a piezoelectric material at a temperature of less than 300°C is performed at temperatures below 450°C. At temperatures below 300°C (or more typically below 300°C), one or more III-V semiconductors This may also include depositing II-VI semiconductors.

[0110] One or more piezoelectric materials may include non-ferroelectric piezoelectric materials. Ferroelectric materials are, Typically, this requires poling under a strong applied electric field (i.e., after deposition). Electroelectric piezoelectric materials typically do not require polling.

[0111] The piezoelectric material of a piezoelectric actuator typically has a capacitance of less than 30 pC / N, or more typically 2 Piezoelectric constant having a magnitude of less than 0 pC / N, or more typically less than 10 pC / N. d 31 It has one or more piezoelectric materials, typically less than 30 pC / N, or more typically Typically having a size of less than 20 pC / N, or more typically less than 10 pC / N, Piezoelectric constant d 31It holds.

[0112] Forming the first electrode typically involves a metal (titanium, platinum, aluminum) on the nozzle formation layer. This includes depositing one or more layers of (such as aluminum, tungsten, or alloys thereof). The metal can be deposited by PVD (e.g., at low temperatures). The metal is typically 450 It is deposited at temperatures below 300°C (or, more typically, below 300°C).

[0113] Forming a second electrode on a piezoelectric material typically involves placing a metal (titanium, platinum, Depositing one or more layers of aluminum, tungsten, or alloys thereof. It includes. The metal can be deposited by (e.g., low temperature) PVD. The metal is typically 4 They are deposited at temperatures below 50°C (or, more typically, below 300°C).

[0114] This method involves a substrate, a CMOS control circuit, and a piezoelectric actuator (for example, a first electrode, a piezoelectric actuator). The body, including the second electrode, the fluid chamber, and the droplet ejection output are integrally formed (for example) This includes integrating the components and thereby forming a monolithic droplet ejector assembly. It is possible. The droplet ejector assembly can be a droplet ejector chip.

[0115] The optional features disclosed in relation to any aspect of the present invention are optional features of each aspect of the present invention. This is a selective characteristic. [Brief explanation of the drawing]

[0116] The present invention will now be explained with reference to the following diagram. [Figure 1] This is a schematic cross-sectional view of a prior art droplet ejector chip. [Figure 2]This is a cross-sectional view of a droplet ejector tip showing a single actuator according to the present invention. [Figure 3] Figure 2 is a further schematic cross-sectional view of a monolithic droplet ejector chip substrate having a CMOS and actuator. [Figure 4] The following shows a possible droplet ejector chip configuration according to the present invention. [Figure 5] The following shows a possible droplet ejector chip configuration according to the present invention. [Figure 6] This shows the configuration of the control printhead. [Figure 7] This shows the configuration of the control printhead. [Figure 8] This is a schematic diagram of a printed circuit board control circuit. [Figure 9] Figures 9(a) to 9(c) show actuator control pulses. The X-axis represents time, and the Y-axis represents voltage per 1 μm of piezoelectric material thickness. [Figure 10] Three alternative droplet ejector chips are shown, illustrating a single-actuator configuration. [Figure 11] Three alternative droplet ejector chips are shown, illustrating a single-actuator configuration. [Figure 12] Three alternative droplet ejector chips are shown, illustrating a single-actuator configuration. [Modes for carrying out the invention]

[0117] Referring to Figure 1, a known class of inkjet printhead 1 is a silicon printer The device includes a piezoelectric actuator element 2 formed as a layer on the head substrate 4. Each ethode element is in fluid communication with the inductor 12 through the conduit 8, and has a 6-25 μm diameter. The walls of the fluid chamber 6 are formed, and are in fluid communication with the nozzle 10 having a radius within the range of [specify radius]. The ink fluid chamber and conduit are covered with a nozzle definition layer 16 which has a nozzle inside. It is formed within the manifold layer 14. The chamber 18 behind each actuator is To draw the fluid into each fluid chamber and discharge it from each nozzle, The tutor provides space for bending. In some embodiments, the chamber is shown in Figure As shown, it can directly lead into the bent cavity. The external controller 20 controls the individual piezoelectric actuators A chip-on feed that switches the data on, has latch and / or nozzle trim data. The actuator is driven via a flexible interconnect 22 that includes a COF (Core of Fiber). The flexible interconnect is a parallel connection that includes individual signal conductors for each piezoelectric actuator. Connects to silicon through 24. Therefore, a pudding with many actuators. In the case of a to-head, a flexible interconnect has many individual signal conductors. For example, 1 If there are 600 nozzles per inch, then there are at least 600 individual nozzles per inch. There is a connection. Attaching more than 600 conductive wires per inch is not guaranteed to be achieved. It is always difficult. The goal of high-resolution printers is to exceed 1000 pixels per inch. Yes. This means that in order to achieve a high target resolution, fixed areas that cannot be scanned are fixed. It is extremely important to achieve this with a print head that matches the page width. Therefore, per inch A 1200-dot, 4-color printhead requires 4800 connections per inch. ru.

[0118] Referring to Figure 2, the droplet ejector according to the present invention (which functions as a droplet ejector assembly) The ejector chip 100 has a CMOS control circuit 104 on the first surface 106 of the substrate. It comprises a silicon substrate 102. Furthermore, circuit components exist on the opposite second surface 108. can be provided herein. A person skilled in the art will understand that a CMOS circuit comprises both a doped region of a substrate and a metallization layer and interconnections formed on a first surface of the substrate. The sub strate has an opening 110 that has been DRIE etched. This opening has inclined side walls and may be formed using anisotropic etching. In general, a plurality of layers, shown as 112 and 114, are formed on the first surface of the substrate. Layer 112 is a CMOS metalliz ation layer, which comprises metal conductive traces and passivati on insulators such as SiO₂, SiN, SiON, etc. All or some of these layers, in this example, are formed of AlN or ScAlN, and in order to form a piezoelectric actuator element 118 comprising a piezoelectric body 120 that may be formed of another suitable piezoelectric material processable at a temperature lower than 450°C, it may (or may not) extend across opening 110. The piezoelectric actu ator element forms a diaphragm with a layer 115 of a material such as silicon, silicon oxide, silicon nitride, or derivatives thereof, and has a passivation layer 113 that prevents an applied potential from contacting the fluid .

[0119] The at least one metallization layer 112 comprises interconnections that conduct signals from an external controller 20 to a control circuit and from the control circuit to the piezoelectric actuator element, in particular to a first electrode and a second electrode (not shown in Figure 2 ) arranged to apply a potential difference across the piezoelectric body, thereby actuating the piezoelectric body .

[0120] The piezoelectric actuator element 118 outputs ink (inkjet pri ​​​(In the case of an additive manufacturing printer), or receive another printable fluid (for example, in the case of an additive manufacturing printer) Furthermore, the wall of the fluid chamber 122 is defined, which communicates with the nozzle 126 for discharging liquid. The conduit is defined by a channel defining layer 128 attached to a layer on the surface of the substrate. For example, defined by DRIE etching and / or wafer bonding of a silicon substrate. The nozzle definition layer 130 provides the outer surface of the print head and defines the nozzle 126. It has an opening. The piezoelectric actuator element 118, chamber 122, and nozzle 126 Together, they form a droplet ejector, generally referred to as 101.

[0121] Figure 3 shows the CMOS / actuator substrate and electrical components of the droplet ejector chip 100 shown in Figure 2. Further details of the connection are shown. The CMOS control circuit is patterned on doped silicon 132. It comprises a region and a metallization layer 134. The number of metallization layers is CM Depending on the complexity of the OS control circuit, three layers should be sufficient for many applications. The metallization layer 112 has a cable 138 connected to the CMOS control circuit, and Later, the third is located on the opposite side of the piezoelectric element 140 and in contact with the opposite side of the piezoelectric element 140. Extending from the contact pad 136, connected to electrode 1 140 and electrode 2 142 Here, two electrodes are shown, but two or more electrodes can be placed on both sides of the piezoelectric material, or in different regions. An extreme is possible.

[0122] Multiple droplet ejectors (individual piezoelectric actuators, fluid chambers, and droplet outlets) A single droplet ejector chip 1 (which functions as a droplet ejector assembly) has Referring to Figures 4 and 5, which show the print head formed from 00, a limited number of signal leads The flexible cable interconnect 138, which has a body, connects to an external controller via wire 144 Multiple droplets, shown as 101, are used to dispense ink of different colors. Connects to a printhead assembly equipped with a droplet ejector. Ejector chips are typically formed from a single CMOS / actuator substrate. In these examples, the CMOS control circuit, as well as the main part of the CMOS control circuit 104, It includes a separate circuit element 104' associated with the droplet ejector, which, for example, each pressure This may include latch and ejector transistors for electric actuators.

[0123] Figures 6 and 7 show a print head (Figure 6) with a single droplet ejector chip / substrate. For, and having multiple different droplet ejector chips having individual substrates, pre Flexible cable 144 for the headhead (Figure 7), flexible cable mutual The arrangement of connection 138 and droplet ejector chip 100 is shown. The control circuit is integrated on the substrate. Therefore, the number of signal conductors may be less than the number of individual actuators. In some cases, the number of actuators may be far fewer than the number of separate actuators.

[0124] Figure 8 is a block diagram of the control circuit of the print head according to the present invention. Actuator Control is provided by the machine controller 220 and the CMOS circuit 1 in the droplet ejector chip 100. They are distributed between 04. They are one or more flexible cable interconnects 13 Multiple actuators 12 are partially connected by conductors extending through 8. 0 is controlled by applying potentials to the respective electrodes 140, 142. Machine cont roller comprises at least a processor 200, such as a microprocessor or a microcontroller, having a memory 202 for storing associated data and program codes. A wired or wireless electronic interface 204 receives input data from an external device driver . Those skilled in the art will understand that the machine controller may be distributed among several separate components or functional modules, for example, one component that converts an image into a pixelated pattern for printing using a dither matrix, and a separate component that converts the pixelated pattern into print patterns for different nozzles.

[0125] The machine controller may comprise at least one waveform generator and a voltage amplifier 208 that provides a continuous pattern of actuator control pulses (shown in FIG. 9) to the print head through one or more drive signal conductors 210. A ground conductor 212 also extends from the machine controller to the droplet ejector chip 100. (For clarity, the ground connection within the print head is not shown.) The processor 200 typically generates digital control signals 214 as a serial bus, and also transmits a clock signal 216 to the print head, which functions to synchronize the movement of the print head with printing. The connector also provides voltage levels related to the operating voltage of CMOS control electronics.

[0126] Within the print head, contact pads 136 are connected to conductors of a flexible connector, and signals are sent to the CMOS control circuit 104 through the patterned metallization layer 112 The CMOS control circuit activates the individual piezoelectric elements 120 within each piezoelectric actuator. The electrodes 140 and 142 are used to send the material. The control circuit 104 on the substrate 102 controls electrodes 140, Connects to 142 electrically directly (i.e., without further intervening switching semiconductor junctions). The system includes a discharge switch circuit 220, which includes a discharge transistor having an output. The circuit switches the actuator control pulse signal, and one of the electrodes is connected to ground. If left as is, the discharge switch circuit consists of a single transistor per actuator, and It consists of a single transistor per electrode that switches the signal applied to that electrode, and an equivalent amount of transistors. It can be simpler each time. The discharge switch circuit corresponds to mechanism 104' in Figures 4 and 5, for each liquid The part adjacent to the droplet ejector (for example, a transistor, or a transistor and a latch) It can be dispersed around the substrate.

[0127] The discharge switch circuit does not perform power amplification. Instead, it switches off the actuator control pulse. For each pulse, determine whether each pulse is relayed to the respective actuator. The voltage amplification is performed by the machine controller using amplifier 208.

[0128] The discharge switch circuit is controlled by latch and shift transistors 222, and these It processes the received data, for example, by converting the received serial data and those The data is stored in register 226, and the received data is used to determine the sequence of acts. Control circuit 22 determines which actuator will operate during each launch event. From 4, digital data is received and stored. The control circuit 228 also controls the actuator. Trim day is used to customize the precise timing of voltage switching. The nozzle also remembers this, which is typically determined during the calibration step in setup. This shows the physical layout, security information, and / or nozzle operation count history information. Configuration data 230 can be stored. The control circuit 224 also controls sensors 232, 234, 236 Data is received from various sources, and some of these are used to control individual actuators, such as the nozzle. Associated with the fill level sensor, and some of these are print heads It senses the overall function, for example, parameters related to the temperature sensor.

[0129] Figure 9 shows the waveform generated by the waveform generator or voltage amplifier 206 in an alternative embodiment. Below are three possible drive waveforms. The X-axis represents time (in milliseconds), and the Y-axis represents the time. This is the potential per micrometer of cutter thickness. In this example, the piezoelectric material is made of a non-ferroelectric material. Because it is manufactured, the pulse can be applied in either direction. In Figure 9(a), the signal is It has a default voltage of 0, and in each pulse, it switches to a positive potential, and after a predetermined period of time It returns to zero. In Figure 9(b), the signal has a default voltage of 0, and initially (piezoelectric actuator (To deform the ether in one direction) it is switched to a positive potential, and then (piezoelectric actuator) (To deform the voltage in the opposite direction) it is switched to a negative potential, and then returns to zero. Figure 9 In (c), the signal has a default voltage of 200V and is switched to a voltage of -200V. (The direction of the electric field of the piezoelectric material is reversed), and then the voltage returns to 200V.

[0130] During operation, processor 200 inputs print data such as bitmaps in digital form. The data is received through the surface 204 and processed by known means, a series of Print commands are sent to each droplet ejector chip via serial connection 216. The print command specifies whether and when to eject droplets during the print cycle. It can be as detailed as the instructions for each droplet ejector chip. In one embodiment, waveform generation The device generates repetitive voltage pulses suitable for application to the electrodes of individual piezoelectric actuators. These are accompanied by a time interval for determining the time between droplet ejection events at the print head. , periodic. Alternatively, the voltage amplifier 208 uses a single voltage level among multiple voltage levels. The bell can be supplied to and maintained in the printhead assembly. Ejection within the droplet ejector tip. The output transistor switches these voltages according to the CMOS control circuit.

[0131] One or more waveform generators are not located on the print head, and multiple piezoelectric actuaries Because it is used to drive the engine, it generates a large amount of heat without causing problems. This is possible. Because there are virtually no constraints on the board space, it is possible to select and optionally do so. A relatively complex circuit, adapted to carefully control the waveform shape with a variable slew rate. This is possible, and the power amplifier operates when all actuators that can operate simultaneously are operating together. It can be selected to generate the desired voltage up to the maximum possible current requirement.

[0132] The control circuits 224 on each printhead board communicate the print command via the serial connection 216. It receives instructions and processes them (for example, converting serial instructions to parallel instructions). Referencing the clock signal 214, during each print cycle, individual pressures are used to eject droplets. It is determined whether the electric actuator should be activated, and this data is entered into latch 222. The data is then ejected. At the appropriate point during each print cycle, the latched data is ejected. The signal is passed to the circuit, and the received printed waveform is then used to control the output of each actuator element. Either electrode is switched to, and a droplet ejection cycle is executed, or each action Both electrodes of the tuner element remain connected to ground, and the droplet ejector ejects droplets. If the ejection cycle is not performed, the droplet ejection cycle will not be executed.

[0133] Sensors 232, 234, and 236 are monitored during printing. The received print waveform is then used to monitor the data. The precise timing for switching the electrodes of each actuator element depends on the temperature-sensitive CMOS element. It can be changed in response to the temperature measurement used.

[0134] Each nozzle is due to the print head assembly, due to its operating life, (single Slightly different based on wafer manufacturing variations (on a wafer or between wafer lots) It may have discharge characteristic behavior (droplet volume, velocity). This data is generated by a CMOS control circuit. To change the drive waveform of a specific nozzle, for example, change the duration of the operating pulse. Alternatively, to switch to a different level, or to switch a specific nozzle to a different drive waveform. It can be used for that purpose.

[0135] The viscosity and surface tension of some inks are very sensitive to temperature, which ultimately leads to... The droplet ejection characteristics are changed accordingly. A specific printing pattern causes a specific nozzle to continuously eject droplets. One nozzle fires, while the other fires sporadically. This creates a variable heat pattern. The monitored temperature allows for appropriate actions such as changing the waveform and / or reducing the printing speed. For this purpose, a control circuit is used to feed control information back to the controller. It is possible.

[0136] The shift register moves the droplet ejection pattern information to the latch register. Therefore, The shift register is interfaced with a serial connection and operates in a given print cycle. Then, all print data is moved to the latch register. The latch register receives the print command. To begin, interface with the output register.

[0137] The droplet ejector chip is mounted on a substrate 102 and includes CMOS control circuits 104, 134, and gold The CMOS circuit is fabricated by first forming the p-type interconnection layer 112. Formed by a standard CMOS processing method including ion implantation into a substrate or n-type substrate, Interconnection will also be done later using ion implantation, chemical vapor deposition, physical vapor deposition, etching, and chemical mechanical planarization. and / or formed by standard processes such as electroplating.

[0138] An additional layer of material, including electrodes 140 and 142, is deposited using continuous thin-film deposition technology. Then, it is formed on the substrate together with the intervening piezoelectric material. Each step is directed to the CMOS control circuit. Damage to the piezoelectric material must be avoided. Piezoelectric materials are produced by PVD (including low-temperature sputtering). Formed from materials such as AlN or ScAlN, which can be deposited at temperatures below 450°C. The electrodes are made from, for example, titanium, platinum, aluminum, tungsten, or alloys thereof. The fluid channels and openings passing through the substrate are formed using etching procedures such as DRIE. It can be formed using the DRIE etching process of the silicon MEMS substrate. The channel definition layer 128 is formed by DRIE etching of the silicon MEMS substrate. It can be formed using nozzle bonding and wafer bonding. The nozzle defining layer is used to define the channel later. By deposition on top or adhesion to the channel, metal, silicon MEMS wafers, or plastics can be deposited. It can be formed from plastic material. Each droplet ejector tip has a flexible interconnect. It is connected to the machine controller via this. In contrast to the prior art device shown in Figure 1. The number of individual conductors within a flexible interconnect is limited, for example, 4 to 16 conductors. That is the case.

[0139] The material forming the piezoelectric element is used in CMOS control systems in which a piezoelectric actuator containing the piezoelectric element is formed. It is not possible to use PZT, and therefore it is not PZT, in order to avoid damaging the circuit. Therefore, piezoelectric actuators, depending on their exact composition, are usually better than PZT. At least one order of magnitude, and sometimes two orders of magnitude, a much lower piezoelectric constant d 31 It has. On the surface, this makes it impossible for the print head ejector to function properly. However, for the following reasons, the print head ejector will not operate We found that it is possible to do so. Piezoelectric materials such as AlN, ScAlN, and ZnO have a higher dielectric breakdown voltage than PZT. Because it can be operated at higher potential gradients, the corresponding force can be the actuator. This makes it possible to apply it to. Piezoelectric materials such as AlN, ScAlN, and ZnO have a higher Young's modulus than PZT. This allows them to increase the power they can grant. -In some embodiments, actuator control pulses may be generated off-chip, pressure Switched by a transistor having a control circuit on a substrate supporting the electric actuator. This allows for the application of relatively high voltages to the piezoelectric element when needed. - Some piezoelectric materials other than PZT are non-ferroelectric, therefore, due to an electric field in the opposite direction, They operate in different directions, resulting in larger changes in the electric field (from negative electric field strength to positive electric field strength, or (Conversely) this allows for increased variation in the force applied to the actuator during the printing cycle. ru.

[0140] The droplet ejector tip may have alternative configurations, some of which are shown in Figures 10-12. The mechanisms corresponding to those already described are marked with corresponding numbers. In embodiments 10 and 11, for example, a DRIE etching procedure or anisotropic etching is used. Using the procedure, a silicon through-hole is formed that penetrates the silicon substrate 102. The body chamber 122 extends within the substrate, and the head volume 110 has an outlet for the airflow during operation. provide.

[0141] Referring again to Figures 4 and 5, the flexible interconnect is attached to the edge of the print head. It can be used to drive several or many individual droplet ejector chips. For example, droplet ejection for different colored inks (or other materials in the case of an additive printer). The stippling, or droplet ejectors for different colored inks (or other materials), are all individually made. It can be formed on a single continuous substrate within the droplet ejector chip.

[0142] In an alternative embodiment, a machine controller including a waveform generator, and a droplet ejector Instead of the waveform transmitted to the terminal assembly and the CMOS control circuit on it, the CMOS control Your circuit activates the piezoelectric actuators and applies power to one or more electrodes of each piezoelectric actuator. The voltage is, for example, between ground and a fixed voltage, or between multiple fixed voltage levels. Switching between multiple fixed voltage levels, one or more of which may be grounded. Therefore, droplet ejection occurs. In this case, the flexible connector 138 is the machine controller Includes one or more conductors that transmit a fixed voltage from the trailer to the droplet ejector tip.

Claims

1. A droplet ejector assembly for a print head, wherein the droplet ejector assembly The substrate has a first surface and a second surface opposite to it, and is equipped with a CMOS control circuit. A substrate, a plurality of layers on the first surface of the substrate, and a fluid channel having a droplet discharge port. A numb, formed by one or more of the aforementioned layers, and a piezoelectric material, and in contact with the piezoelectric material A piezoelectric actuator element comprising a first electrode and a second electrode, and the piezoelectric actuator The cutter element defines a portion of the fluid chamber, and at least one of the electrodes, The droplet ejector is electrically connected to the CMOS control circuit and has a droplet outlet. It is equipped with a fluid chamber, and the piezoelectric actuator element is separate from the droplet discharge port. The piezoelectric body is formed of one or more piezoelectric materials that can be processed at a temperature of less than 450°C, and the droplet Ejector assembly.

2. The piezoelectric material comprises one or more nonferroelectric piezoelectric materials, and the CMOS control circuit is the To bend the piezoelectric body in a first direction, a potential gradient is applied to the piezoelectric body in a first direction. Next, in order to deform the piezoelectric material in the opposite second direction, the potential gradient is applied to the piezoelectric material in the opposite direction. The piezoelectric element is configured to be activated by applying a power in a specific direction, according to claim 1. The droplet ejector assembly described.

3. The piezoelectric material has a relative permittivity ε less than 100. ｒ A droplet edge having the characteristics of claim 1 or 2 Ejector assembly.

4. The piezoelectric material has a dielectric breakdown voltage of more than 100 V / μm, and the CMOS control circuit is 1 A prior claim is configured to apply a potential gradient greater than 00 V / μm into the piezoelectric body. A droplet ejector assembly as described in any one of the items.

5. The CMOS control circuit comprises (a) a digital register and (b) a nozzle trimming calculation circuit. and / or one of the following: (c) a register, (d) a temperature measurement circuit, or (c) a fluid chamber filling detection circuit. A droplet ejector assembly according to any one of the prior claims, comprising one or more of the above.

6. The CMOS control circuit comprises an ejection transistor as described in any one of the prior claims. The droplet ejector assembly.

7. The CMOS control circuit is equipped with an electrical input for receiving actuator drive pulses. The piezoelectric actuator or at least one electrode of each piezoelectric actuator is connected to the receiving The transmitted actuator drive pulse is switched on or off, thereby, The piezoelectric actuator is configured to be operated selectively, according to the prior claims A droplet ejector assembly as described in item one.

8. The CMOS control circuit is formed by one or more layers on the same substrate, and different At least three of the pressures define a portion of each fluid chamber and droplet outlet. It is configured to operate the electric actuator elements individually and selectively, and arbitrarily Furthermore, the actuators within the at least three actuator elements are of different colors or compositions A droplet ejector according to any one of the prior claims, configured to discharge the fluid Coctor assembly.

9. The at least three actuator elements are located on the substrate and the CMOS control The circuit is connected to a flexible printhead cable having one or more electrical signal conductors. The CMOS control circuit responds to an operation command received through the same signal conductor. , the actuator element among the at least three actuator elements is individually or The droplet ejector assembly according to claim 8, configured to be operated selectively Ri.

10. The CMOS control circuit receives an operation control signal from the signal conductor. Furthermore, we want to operate at least twice the number of piezoelectric actuator elements individually and selectively. A droplet ejector assembly according to claim 8 or 9, configured as follows.

11. One or more of the aforementioned layers are in contact with a liquid fluid of a different color or composition. A minimum of three separate fluid supply manifolds for supplying the fluid chamber A droplet according to any one of claims 8 to 11, further comprising a fluid supply block defining... Ejector assembly.

12. The fluid supply manifold supplies fluid of the same composition to each of the multiple fluid chambers. Therefore, it is provided with a fluid conduit connected to each of the plurality of fluid chambers, and the plurality of fluids The piezoelectric actuator elements defining each part of the chamber are part of the CMOS control circuit. Therefore, optionally, in response to an operation command received through the same signal conductor, The droplet ejector assembly according to claim 11, which is operated.

13. The CMOS control circuit, in order to cause droplet ejection, is grounded and a single fixed non-zero power source. A voltage line, or multiple fixed voltage lines of different voltages, one or more of which are grounded Possible, one or more of the fixed voltage lines to one or more of the piezoelectric actuator's dual power lines The pole is configured to be connected in a switchable manner, as described in any one of the prior claims. Droplet ejector assembly.

14. The CMOS control circuit stores data, or the data stored by the CMOS control circuit. Typically, it responds to measurements from one or more sensors located within the droplet ejector assembly. Then, the voltage pulse applied to one or more electrodes of one or more piezoelectric actuators is corrected. A droplet ejector assembly according to any one of the prior claims, configured to be such as 。

15. A controller, which communicates electronically with the controller, and which is controlled by the controller An in- A inkjet printer wherein the controller generates a series of actuator drive pulses The system further comprises a pulse generator configured to generate the pulses of the droplet ejector assembly. The air input receives actuator drive pulses through the electrical connection to the controller. The CMOS control circuit of one or more droplet ejector assemblies controls a plurality of piezoelectric actuators. The piezoelectric actuator or at least one of the piezoelectric actuators among the ETters The pole is switched on or off to the received actuator drive pulse. This is configured to selectively operate the piezoelectric actuator. Inkjet printer.

16. The system comprises multiple droplet ejector assemblies, and pulses from the pulse generator are generated from multiple droplets. It is transmitted to multiple control circuits, which are part of the droplet ejector assembly, and the controller , further configured to generate a digital control signal, wherein the digital control signal is previously The droplet ejector assembly is conducted, and the CM of the droplet ejector assembly The OS control circuit processes the data to determine which actuator drive pulse triggers droplet ejection. Therefore, at least one of the piezoelectric actuators of the droplet ejector assembly An inkjet printer according to claim 15, which determines whether conduction occurs to one electrode.

17. A droplet ejector assembly for a droplet ejector according to any one of the prior claims A method for manufacturing, wherein the method provides a substrate having a first surface, and the first Forming a CMOS control circuit on the surface of the above-mentioned 1, and forming multiple layers on the surface of the above-mentioned 1. The plurality of layers comprises a first electrode and a second electrode, and a piezoelectric material. A method comprising a piezoelectric actuator element.

18. A droplet ejector assembly according to any one of claims 1 to 14, or claim 15 Alternatively, a method for operating the inkjet printer described in 16, wherein the CMOS control cycle The circuit receives a digital operation control signal, processes the digital operation control signal, and dispenses droplets. A method for selectively activating a piezoelectric actuator element in order to cause a certain effect.

19. Generate actuator drive pulses and, through electrical connections, transmit them to the droplet ejector. The steps of transmitting to the assembly and the piezoelectric actuating among a plurality of piezoelectric actuators At least one electrode of the electrode or each piezoelectric actuator is connected to the received actuator. The piezoelectric actuator is switched on or off to the drive pulse, thereby controlling the piezoelectric actuator. The method according to claim 18, comprising the step of selectively activating a data setter.

20. Generate multiple different sequences of actuator drive pulses and connect them separately using electrical connections. Through the connection, conduction is carried to the droplet ejector assembly and multiple piezoelectric actuators The piezoelectric actuator or at least one electrode of each piezoelectric actuator among the actuators , receiving from a variable pulse among the plurality of different sequences of actuator drive pulses Switchable connection or connection to one or more received actuator drive pulses. The method according to claim 18 or 19, further comprising the action of deactivating the device.

21. To cause droplet ejection, a connection to ground and a fixed voltage line, or multiple lines of different voltages are required. A claim comprising switching an electrode between a connection to a fixed voltage line and, and then returning it to ground. The method described in any one of items 18 to 20.

22. A droplet ejector assembly for a print head, wherein the droplet ejector assembly The substrate has a first surface and a second surface opposite to it, and is equipped with a CMOS control circuit. A substrate, a plurality of layers on the first surface of the substrate, and a fluid channel having a droplet discharge port. A numb, formed by one or more of the aforementioned layers, and a piezoelectric material, and in contact with the piezoelectric material A piezoelectric actuator element comprising a first electrode and a second electrode, and the piezoelectric actuator The cutter element defines a portion of the fluid chamber, and at least one of the electrodes, The droplet ejector is electrically connected to the CMOS control circuit and has a droplet outlet. A fluid chamber comprising one or more piezoelectric materials that can be processed at temperatures below 450°C. A droplet ejector assembly formed from a material.

23. The piezoelectric material has a dielectric breakdown voltage of more than 100 V / μm, and the CMOS control circuit is 1 Claim 22, configured to apply a potential gradient greater than 00 V / μm into the piezoelectric body. The droplet ejector assembly described above.

24. The CMOS control circuit is equipped with an electrical input for receiving actuator drive pulses. The piezoelectric actuator or at least one electrode of each piezoelectric actuator is connected to the receiving The transmitted actuator drive pulse is switched on or off, and thereafter The piezoelectric actuator is configured to be operated selectively, or the The CMOS control circuit uses ground and a single fixed non-zero voltage line to trigger droplet ejection. Or multiple fixed voltage lines of different voltages, one or more of which may be grounded. One or more of the multiple fixed voltage lines are connected to one or more electrodes of the piezoelectric actuator. A droplet ejector according to claim 22 or 23, which is configured to be connected in a switchable manner. Assembly.

25. A controller, which communicates electronically with the controller, and which is controlled by the controller Controlled, one or more droplet ejector assemblies according to any one of claims 22 to 24 An inkjet printer comprising a BR, wherein the controller is a series of ACT The system further comprises a pulse generator configured to generate a tuner drive pulse, and the droplet e The electrical input of the ejector assembly, through the electrical connection to the controller, activates Upon receiving the inverter drive pulse, the CM of one or more of the droplet ejector assemblies The OS control circuit controls the piezoelectric actuator or each piezoelectric actuator among the plurality of piezoelectric actuators. At least one electrode of the actuator is connected to the received actuator drive pulse. The piezoelectric actuator can be selectively connected or disconnected in a switchable manner, thereby enabling selective operation of the piezoelectric actuator. An inkjet printer that is configured to move.

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