Micro-electromechanical device that incorporates covering formations for actuators of the device

• US 6,834,939 B2
• Filed: 11/17/2003
• Issued: 12/28/2004
• Est. Priority Date: 11/23/2002
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Gordon, Raquel Yvette
• Application Number:
  US10/713,070
• Publication Number:
  US 20040100530A1
• Time in Patent Office: 407 Days
• Field of Search: 347/54, 347/68, 347/69, 347/70, 347/71, 347/72, 347/50, 347/40, 347/20, 347/44, 347/47, 347/27, 347/63, 399/261, 361/700, 310/328-330, 298/901
• US Class Current: 347/54
• CPC Class Codes: B41J 2/14427 Structure of ink jet print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/1601 Production of bubble jet print heads B41J2/1606, B41J2/162 take precedence
• CPC Class Codes: B41J 2/1623 bonding and adhesion
• CPC Class Codes: B41J 2/1626 etching
• CPC Class Codes: B41J 2/1628 dry etching
• CPC Class Codes: B41J 2/1629 wet etching
• CPC Class Codes: B41J 2/1631 photolithography
• CPC Class Codes: B41J 2/1632 machining
• CPC Class Codes: B41J 2/1635 dividing the wafer into individual chips
• CPC Class Codes: B41J 2/1637 molding
• CPC Class Codes: B41J 2/1639 sacrificial molding
• CPC Class Codes: B41J 2/1642 thin film formation by CVD [chemical vapor deposition]
• CPC Class Codes: B41J 2/1643 thin film formation by plating
• CPC Class Codes: B41J 2/1645 thin film formation by spincoating
• CPC Class Codes: B41J 2/1646 thin film formation by sputtering
• CPC Class Codes: B41J 2/1648 Production of print heads with thermal bend detached actuators
• CPC Class Codes: B41J 2/16585 for paper-width or non-reciprocating print heads
• CPC Class Codes: B41J 2/17513 Inner structure
• CPC Class Codes: B41J 2/17596 Ink pumps, ink valves
• CPC Class Codes: B41J 2002/041 Electromagnetic transducer
• CPC Class Codes: B41J 2202/21 : Line printing
• CPC Class Codes: G06F 21/78 : to assure secure storage of data address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: G06F 21/79 : in semiconductor storage media, e.g. directly-addressable memories
• CPC Class Codes: G06F 21/86 : Secure or tamper-resistant housings
• CPC Class Codes: G06F 2221/2129 : Authenticate client device independently of the user
• CPC Class Codes: G06K 1/121 : by printing code marks applying code marks to labels B65C9/46; marking or coding completed packages B65B61/26
• CPC Class Codes: G06K 19/06037 : multi-dimensional coding
• CPC Class Codes: G06K 7/14 : using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1417 : 2D bar codes
• CPC Class Codes: G11C 11/56 : using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
• CPC Class Codes: H04N 23/00 : Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: H04N 5/2628 : Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation

Abstract

A micro-electromechanical device includes a substrate that incorporates drive circuitry. An elongate actuator has a fixed end that is connected to the substrate so that the actuator can receive an electrical signal from the drive circuitry and a movable end. The actuator is configured so that the movable end is displaced relative to the substrate on receipt of the electrical signal. A motion-transmitting structure is fast with the movable end of the actuator. The motion transmitting structure is connected to a working member so that movement of the actuator is translated to the working member. A covering formation is positioned on the substrate so that the substrate, the covering formation and the motion transmitting structure define an air chamber, the actuator being positioned within the air chamber.

Claims

1. A micro-electromechanical device that comprises

a substrate that incorporates drive circuitry;

an elongate actuator that has a fixed end that is connected to the substrate so that the actuator can receive an electrical signal from the drive circuitry and a movable end, the actuator being configured so that the movable end is displaced relative to the substrate on receipt of the electrical signal;

a motion-transmitting structure that is fast with the movable end of the actuator, the motion transmitting structure being connected to a working member so that movement of the actuator is translated to the working member; and

a covering formation that is positioned on the substrate so that the substrate, the covering formation and the motion-transmitting structure define an air chamber, the actuator being positioned within the air chamber.

2. A device as claimed in claim 1, in which the covering formation includes walls that extend from the substrate and a cover that spans the walls, the motion-transmitting structure being shaped so that the cover and the motion-transmitting structure define generally co-planar surfaces that are spaced from, and generally parallel to the substrate, an opening being defined between the cover and the motion-transmitting surface to facilitate relative displacement of the cover and the motion-transmitting surface.

3. A device as claimed in claim 2, in which the actuator includes at least one elongate actuator arm of a conductive material that is capable of thermal expansion to perform work, the actuator arm having an active portion that defines a heating circuit that is connected to the drive circuitry layer to be resistively heated on receipt of the electrical signal from the drive circuitry layer and subsequently cooled on termination of the signal, and a passive portion which is insulated from the drive circuitry layer, the active and passive portions being positioned with respect to each other so that the arm experiences differential thermal expansion and contraction reciprocally to displace the movable member.

4. A device as claimed in claim 3, in which the motion-transmitting structure defines a lever mechanism and has a fulcrum formation that is fast with the substrate and pivotal with respect to the substrate and a lever arm formation mounted on the fulcrum formation, an effort formation being connected between the movable end of the actuator and the lever arm formation and a load formation being connected between the lever arm formation and the working member.

5. A device as claimed in claim 4, in which the lever arm formation, the cover and the walls define a unitary structure with the lever arm formation being connected to the walls with a pair of opposed torsion formations that are configured to twist as the lever formation is displaced.

6. A device as claimed in claim 4, which includes nozzle chamber walls that are positioned on the substrate and a roof wall, the walls and the motion-transmitting structure defining a nozzle chamber and the roof wall defining an ejection port in fluid communication with the nozzle chamber, the working member being in the form of a fluid ejection device that is positioned in the nozzle chamber, such that displacement of the working member results in ejection of fluid in the nozzle chamber from the ejection port, the substrate defining a fluid inlet channel in fluid communication with the nozzle chamber to supply the nozzle chamber with fluid.

7. A device as claimed in claim 6, in which the roof wall, the lever arm formation and the cover are generally co-planar, with a slotted opening being defined between the roof wall and the lever arm formation to accommodate relative movement of the lever arm formation and the roof wall.