Fluid-dispensing chip

• US 6,820,968 B2
• Filed: 07/01/2002
• Issued: 11/23/2004
• Est. Priority Date: 07/15/1997
• Status: Expired due to Fees

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Pham, Hai
• Assistant Examiner(s): Nguyen, Lam S
• Application Number:
  US10/184,883
• Publication Number:
  US 20020180857A1
• Time in Patent Office: 876 Days
• Field of Search: 347/54, 347/68, 347/112, 347/70, 347/71, 347/56, 347/65
• US Class Current: 347/70
• CPC Class Codes: B41J 2/04 generating single droplets or particles on demand
• CPC Class Codes: B41J 2/14 Structure thereof only for on-demand ink jet heads
• CPC Class Codes: B41J 2/14314 Structure of ink jet print heads with electrostatically actuated membrane
• CPC Class Codes: B41J 2/16 Production of nozzles
• 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 2/16585 for paper-width or non-reciprocating print heads
• CPC Class Codes: B41J 2/17503 Ink cartridges
• 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 21/79 : 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 19/073 : Special arrangements for circuits, e.g. for protecting identification code in memory protection against unauthorised use of computer memory G06F12/14
• 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 1/2112 : using still video cameras
• CPC Class Codes: H04N 1/2154 : the still video camera incorporating a hardcopy reproducing device, e.g. a printer
• CPC Class Codes: H04N 2101/00 : Still video cameras
• 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 fluid-dispensing chip has a wafer substrate that incorporates drive circuitry. A nozzle assembly is positioned on the wafer substrate. The nozzle assembly has nozzle chamber walls and a roof wall that define a nozzle chamber and a fluid ejection port in the roof wall and an electrostatic actuator. The actuator has a first planar electrode positioned on the wafer substrate. A second planar electrode is positioned in the nozzle chamber and is displaceable towards and away from the first planar electrode to eject fluid from the fluid ejection port. The first planar electrode and the second planar electrode are connected to the drive circuitry so that a potential difference can be applied between the planar electrodes to displace the second planar electrode towards and away from the first planar electrode. At least one of the nozzle chamber walls and the wafer substrate define a fluid inlet in fluid communication with the nozzle chamber and a fluid supply source.

Claims

1. A fluid-dispensing chip that comprises

a wafer substrate that incorporates drive circuitry, and

a nozzle assembly positioned on the wafer substrate, the nozzle assembly comprising nozzle chamber walls and a roof wall that define a nozzle chamber and a fluid ejection port in the roof wall, and an electrostatic actuator that comprises

a first planar electrode positioned on the wafer substrate, and a second planar electrode that is positioned in the nozzle chamber and is displaceable towards and away from the first planar electrode to eject fluid from the fluid ejection port, the first planar electrode and the second planar electrode being connected to the drive circuitry so that a potential difference can be applied between the planar electrodes to displace the second planar electrode towards and away from the first planar electrode,

at least one of the nozzle chamber walls and the wafer substrate defining a fluid inlet in fluid communication with the nozzle chamber and a fluid supply source, said first planar electrode and said second planar electrode defining an air gap between the first and second planar electrodes.

2. A fluid-dispensing chip as claimed in claim 1, in which at least one of the nozzle chamber walls and the substrate define an air path in fluid communication with an external atmosphere so that air flows into and out of the air gap when the second planar electrode is displaced towards and away from the first planar electrode.

3. A fluid-dispensing chip as claimed in claim 1, wherein the electrodes have facing surfaces that are coated with a material having a low coefficient of friction so as to reduce possibilities of stiction.

4. A fluid-dispensing chip as claimed in claim 3, wherein said material comprises substantially polytetrafluoroethylene.

5. A fluid-dispensing chip as claimed in claim 1, in which one of the first and second planar electrodes has at least one projection that extends towards the other electrode to ensure that the electrodes do not touch when the second planar electrode is displaced towards the first planar electrode.

6. A fluid-dispensing chip as claimed in claim 1, wherein said second planar electrode includes a layer of stiffening material for maintaining a stiffness of said second planar electrode.

7. A fluid-dispensing chip as claimed in claim 6, wherein said stiffening material is silicon nitride.

8. A fluid-dispensing chip as claimed in claim 1, wherein the roof wall defines a plurality of etchant holes to facilitate etching of sacrificial layers during construction.