Prior art

US patent 7812505, titled "Piezoelectric microspeaker using microelectromechanical systems and method of manufacturing the same," was granted on October 12, 2010, from an application filed on September 29, 2008. The priority date is December 7, 2007.

To identify the most relevant prior art, we will examine the "Cited By" and "Citations" sections of US7812505 as listed in the patent document. The "Citations" section details prior art referenced during the examination of US7812505.

Here's an analysis of the most relevant patent citations, focusing on those that could potentially anticipate claims under 35 U.S.C. § 102:

US3418436A - Unidirectional condenser microphone

• Full Citation: US3418436A
• Publication Date: December 24, 1968
• Brief Description: This patent describes a unidirectional condenser microphone. While a microphone and a speaker are distinct, both are acoustic transducers. The core technology involves a condenser, which uses electrostatic principles. US7812505, in contrast, focuses on piezoelectric microspeakers.
• Potential Anticipated Claims: Given that US3418436A describes a condenser microphone (electrostatic) rather than a piezoelectric microspeaker, it's unlikely to directly anticipate claims of US7812505 related to piezoelectric layers or resonance change units. However, it may be relevant to the broad concept of micromachined acoustic transducers or diaphragm structures in a very general sense.

US4783821A - IC processed piezoelectric microphone

• Full Citation: US4783821A
• Publication Date: November 8, 1988
• Filing Date: November 25, 1987
• Brief Description: This patent describes an integrated circuit (IC) processed piezoelectric microphone. This reference is highly relevant as it involves piezoelectric technology and MEMS (IC processed implies microfabrication). It specifically deals with a piezoelectric microphone.
• Potential Anticipated Claims: This patent could potentially anticipate claims in US7812505 that broadly cover a piezoelectric layer on an elastic thin layer (claim 1) or methods of forming such layers using semiconductor processes, particularly if the described microphone structure could also function as a speaker. Its relevance would depend on the structural commonalities between the piezoelectric microphone and the piezoelectric microspeaker, especially regarding the fundamental components like the piezoelectric layer and elastic diaphragm.

US4816125A - IC processed piezoelectric microphone

• Full Citation: US4816125A
• Publication Date: March 28, 1989
• Filing Date: November 25, 1987
• Brief Description: This patent is a continuation of US4783821A and also describes an IC processed piezoelectric microphone. It shares similar core technology with US4783821A.
• Potential Anticipated Claims: Similar to US4783821A, this patent could potentially anticipate claims related to the fundamental construction of a piezoelectric device on an elastic layer using microfabrication, as described in US7812505 (e.g., claim 1, and method claims 9, 10, 11).

US4885781A - Frequency-selective sound transducer

• Full Citation: US4885781A
• Publication Date: December 5, 1989
• Filing Date: September 17, 1987
• Brief Description: This patent describes a frequency-selective sound transducer. The focus on "frequency-selective" suggests mechanisms to control resonance or frequency response, which aligns with the resonance change unit in US7812505.
• Potential Anticipated Claims: This patent might anticipate claims related to altering resonance frequencies (claim 7) or general methods for manufacturing sound transducers with specific frequency characteristics (claim 9). The specifics of the "frequency-selective" mechanism would need to be compared to the resonance change unit of US7812505 to determine direct anticipation.

JPH0884396A - Piezoelectric speaker

• Full Citation: JPH0884396A
• Publication Date: March 26, 1996
• Filing Date: September 14, 1994
• Brief Description: This Japanese patent describes a piezoelectric speaker. This is a highly relevant reference as it specifically addresses the same type of device: a piezoelectric speaker.
• Potential Anticipated Claims: This patent could potentially anticipate a wide range of claims in US7812505, especially those related to the basic structure and function of a piezoelectric microspeaker, including the piezoelectric layer on an elastic thin layer (claim 1) and methods of manufacturing such a device (claim 9). The specific details of its construction and any frequency tuning mechanisms would be critical for evaluating anticipation of claims like the resonance change unit (claim 7).

US20030048914A1 - Micromachined piezoelectric microspeaker and fabricating method thereof

• Full Citation: US20030048914A1
• Publication Date: March 13, 2003
• Filing Date: September 12, 2001
• Brief Description: This publication details a micromachined piezoelectric microspeaker and its fabricating method. This is extremely relevant as it explicitly covers both the device type (microspeaker) and the manufacturing method using microelectromechanical systems (MEMS) and piezoelectric material.
• Potential Anticipated Claims: This reference is likely to anticipate many of the claims in US7812505, particularly those defining the piezoelectric microspeaker (claim 1) and the method of manufacturing it (claim 9). Specific comparisons would be needed for the "resonance change unit" (claims 1 and 7) and its specific patterning techniques (claim 8) to determine if these elements are also anticipated.

US6924584B2 - Piezoelectric transducers utilizing sub-diaphragms

• Full Citation: US6924584B2
• Publication Date: August 2, 2005
• Filing Date: December 13, 2002
• Brief Description: This patent describes piezoelectric transducers utilizing sub-diaphragms. The concept of "sub-diaphragms" might relate to structures that influence the vibratory characteristics of the main diaphragm, similar to how the resonance change unit in US7812505 alters stiffness and mass.
• Potential Anticipated Claims: This patent could potentially anticipate claims related to the resonance change unit (claim 1) and its function in altering resonance frequencies (claim 7), depending on whether the "sub-diaphragms" are patterned on the bottom surface of an elastic thin layer or top surface of a piezoelectric layer in a similar manner to the claimed invention.

US20050248238A1 - Thin film piezoelectric resonator, thin film piezoelectric device, and manufacturing method thereof

• Full Citation: US20050248238A1
• Publication Date: November 10, 2005
• Filing Date: June 20, 2002
• Brief Description: This publication discusses a thin film piezoelectric resonator, a thin film piezoelectric device, and its manufacturing method. The use of "thin film piezoelectric" and "resonator" is highly relevant to US7812505, which deals with piezoelectric layers and resonance.
• Potential Anticipated Claims: This patent could potentially anticipate claims related to the piezoelectric layer itself (claim 1, 3, 4, 5) and the methods of forming it (claim 9, 10, 11). Depending on whether the "resonator" features include patterned structures to change resonance frequency, it might also anticipate claims 1 and 7 related to the resonance change unit.

US20060284516A1 - Microphone and a method of manufacturing a microphone

• Full Citation: US20060284516A1
• Publication Date: December 21, 2006
• Filing Date: June 8, 2005
• Brief Description: This publication describes a microphone and a method of manufacturing a microphone. While it is a microphone, the manufacturing methods and underlying piezoelectric principles could be similar to those for a microspeaker.
• Potential Anticipated Claims: This patent might anticipate method claims (claim 9, 10, 11, 12, 13) related to depositing layers and etching a silicon substrate, especially if the described microphone structure incorporates elements that could be adapted for speaker functionality without inventive effort.

US7301212B1 - MEMS microphone

• Full Citation: US7301212B1
• Publication Date: November 27, 2007
• Filing Date: July 30, 2004
• Brief Description: This patent describes a MEMS microphone. Similar to other microphone references, the MEMS technology and use of piezoelectric principles could be relevant to the manufacturing aspects and basic structure, even if the end product is a microphone rather than a speaker.
• Potential Anticipated Claims: This patent could potentially anticipate claims related to the general MEMS manufacturing methods (claim 9, 10, 11, 12, 13) and the fundamental layering of materials (elastic thin layer, piezoelectric layer) as broadly described in US7812505.

USRE40781E1 - Method of providing a hydrophobic layer and condenser microphone having such a layer

• Full Citation: USRE40781E1
• Publication Date: June 23, 2009
• Filing Date: May 31, 2001
• Brief Description: This is a reissue patent concerning a method of providing a hydrophobic layer and a condenser microphone. This reference focuses on condenser microphones and a specific hydrophobic layer, which differs from the piezoelectric and resonance change unit focus of US7812505.
• Potential Anticipated Claims: This patent is less likely to directly anticipate claims of US7812505 due to the differing transducer type (condenser vs. piezoelectric) and the specific focus on a hydrophobic layer, which is not a primary feature of US7812505.