Abstract:
The invention is directed to a hearing instrument for positioning in the ear of a user, incorporating a faceplate having first and second spatially separated sound openings for receiving sound to be provided to respective inlets of a microphone; at least one screen partially blocking the sound openings and positioned to increase effective distance between the first and second spatially separated sound openings; and a housing for containing the microphone, the housing having the faceplate mounted thereon and being sized to fit within the ear of a hearing instrument wearer.

Description:
[0001]     This is a non-provisional application of provisional application Ser. No. 60/366,005 by Oleg Saltykov, filed Mar. 20, 2002. 
     
    
     BACKGROUND  
       [0002]     1. Field of the Invention  
         [0003]     The field of the invention concerns hearing instruments, and particularly hearing instruments with directional microphones.  
         [0004]     2. Description of the Prior Art  
         [0005]     Conventional hearing instruments typically comprise a single omni-directional microphone, which amplifies sound substantially equally from all directions. Because of the omni-directional nature of these hearing instruments, it is often difficult for the wearer to distinguish between a speaker&#39;s voice and background noise. Hearing instruments have therefore been developed that accentuate a speaker&#39;s voice over background noise.  
         [0006]     Directional microphones may be implemented in hearing aids in several ways. In one system, two or more omnidirectional elements are linked to two or more individual ports. One microphone is linked to each port, and electrical signals are processed in order to extract the directional response. Alternatively, one or more directional elements may be linked to two or more ports. One directional microphone is linked to two ports, and the signal is processed by the directional element. The difference in sound intensity on the closely-positioned ports of this type of directional hearing aids is typically negligible and the information about the direction of arriving sound signals is derived from the phase differences of the sound signals.  
         [0007]     However, directional microphones, although suitable for isolating a speaker&#39;s voice, typically have signal-to-noise ratios less than that of omni-directional microphones. Also, directional microphones are very sensitive to wind noise. Thus, in environments with little background or high wind noise, an omni-directional microphone is more desirable for use in processing sound. Therefore, hearing instruments have been developed that include both an omni-directional and a directional microphone, wherein a wearer switches between the two modes as desired.  
         [0008]     Unfortunately, hearing instruments that contain both an omni-directional microphone and a directional microphone typically have lower sensitivity in the directional mode and are larger in size as compared to hearing instruments containing only an omni directional microphone. These dual mode hearing instruments generally have two separate microphone cartridges and a separate toggle switch for switching between them. The total space occupied by these components limits their use to users with ears large enough to accommodate the devices. An unfortunate result is that children often cannot make use of these larger devices.  
         [0009]     Accordingly, the hearing instrument industry seeks reduced sized hearing instruments with improved sensitivity and simplified assembly, yet having the advantages of both omni-directional and directional functionality.  
       SUMMARY OF THE INVENTION  
       [0010]     Embodiments of the invention include a hearing instrument for positioning in the ear of a user, incorporating a faceplate having first and second spatially separated sound openings for receiving sound to be provided to respective inlets of a microphone; at least one screen partially blocking the sound openings and positioned to increase effective distance between the first and second spatially separated sound openings; and a housing for containing the microphone representing the received sound, the housing having the faceplate mounted thereon, the housing being sized to fit within the ear of a hearing instrument wearer and containing the microphone. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The invention is best understood from the following detailed description when read with the accompanying drawings.  
         [0012]      FIG. 1  is a drawing illustrating a cross-sectional view of a preferred embodiment of a microphone section of a hearing instrument.  
         [0013]      FIG. 2  is a drawing illustrating a top view of a preferred embodiment of a microphone component.  
         [0014]      FIG. 3  is another drawing illustrating a cross-sectional view of a preferred embodiment of a hearing instrument.  
         [0015]      FIG. 4  is a picture illustrating a preferred embodiment of a hearing instrument. 
     
    
     DETAILED DESCRIPTION  
       [0016]     The invention will be understood more fully from the detailed description given below and from the accompanying drawings of preferred embodiments of the invention; which, however, should not be taken to limit the invention to a specific embodiment but are for explanation and understanding.  
         [0017]     A hearing instrument in accordance with a preferred embodiment of the invention includes a microphone component having directional and omni-directional functionality. The directional cartridge is preferably assembled with the omni-directional cartridge. A gasket, preferably made of a pressure-sensitive adhesive, may be used to achieve sealing and acoustic leak prevention in the device. One or more windscreens may also be used to cover a portion of the faceplate of the hearing instrument to increase the effective distance between the front and rear receiving ports, which provides for a higher sensitivity in the directional mode.  
         [0018]      FIG. 1  depicts a cross-sectional view of a hearing instrument device according to one preferred embodiment of the invention. A microphone component  102  may be at least partially embedded in a faceplate  104 . In an exemplary embodiment, microphone component  102  is in cartridge form. Inlets to microphone component  102  may be included on a microphone component surface  106 , as further described in connection with  FIG. 2 . The illustrative example depicted in  FIG. 1  has surface  106  perpendicular to the plane of the page. Surface  106 , however, may be any surface of microphone component  102  on which the inlets may be positioned.  
         [0019]     A front port  108  and a rear port  110  may be positioned in faceplate  104  to allow sound to travel to the microphone component inlets. (The terms “front” and “rear” are used herein to facilitate understanding of the invention. The terms, however, do not limit the invention to particular relative configurations, and are merely used for illustration.) The distance between the front and rear ports is preferably in a range of about 5 mm to about  12 mm, although not limited thereto.  
         [0020]     Windscreens  116  and  118  may also be included. Windscreens  116  and  1   18  preferably extend across ports  110  and  108  and the microphone component inlets. Windscreens  116  and  118  may contain holes  112  and  114  (e.g., perforations) and partially obstruct the ports, therefore increasing the effective distance between ports  108  and  110 . The windscreens may also be used in hearing instruments employing a single-element directional microphone with a mechanical switch.  
         [0021]      FIG. 2  depicts an exemplary microphone component that may be used in preferred embodiments of the invention. Microphone component  102  may include a first microphone cartridge  126 , which is preferably located adjacent a second microphone cartridge  128  along surface  130 . In a preferred embodiment, first microphone cartridge  126  may be an omni-directional microphone cartridge, for example, and second microphone cartridge  128  may comprise a directional cartridge. First microphone cartridge  126  preferably includes a front, omni-directional, inlet  132 , while second microphone cartridge  128  preferably includes a rear, directional, inlet  134 , and a front, directional, inlet  136 . Rear inlet  134  preferably further includes an acoustic resistor  138 , such as acoustic mesh, through which sound travels. The cross-sectional area of front inlet  136  is preferably in a range of about 0.05 mm 2  to about 2.0 mm 2 , although not limited thereto.  
         [0022]     Microphone component  102  preferably further includes gasket  122 , which may be used to seal surface  106  of microphone component  102  within the hearing instrument. This helps to minimize acoustical leaks from the device. Gasket  122  preferably comprises a pressure sensitive adhesive, but is not limited thereto.  
         [0023]     Inlets  132 ,  134 , and  136  are preferably located on the same face of the microphone component (e.g., surface  106 ). Locating them on the same face of the assembly may be advantageous by reducing device size, and improving directionality, sensitivity and signal-to-noise ratio and simplification of the assembly procedure. Sensitivity improvements resulting from the operation and configuration of the inventive hearing instrument device are estimated to be in the range of at least about 14 dB.  
         [0024]     Embodiments of the invention may be used for various types of hearing instrument devices, for example, in the ear (ITE), in the canal (ITC), half shell (HS), and behind the ear (BTE) devices. Various circuit types may also be used with the inventive hearing instrument device, including, for example, analog and digital circuits.  
         [0025]      FIG. 3  further depicts a hearing instrument device according to a preferred embodiment of the invention. An electric circuit  140  is operatively connected to the microphone component  102 . The electronic circuitry processes an electrical signal from the microphone component representing the received sound. Microphone component  102  is operatively connected to an electrical switch assembly  120  through electric circuit  140 , so that the microphone component can be switched between directional mode and omni-directional mode. A receiver  142  is operatively connected to electric circuit  140  to generate an acoustical signal in the user&#39;s ear based upon the received sound. A housing  144  preferably surrounds microphone component  102 , electric circuit  140  and receiver  142 . Faceplate  104  may be mounted on housing  144  to accommodate microphone component  102 . Housing  144  may be sized to fit within the ear of a hearing instrument user. The housing may also be configured to be compatible with ITC, HS, and BTE use.  
         [0026]      FIG. 4  is a picture illustrating a preferred embodiment of a healing instrument  150 . Faceplate  104  is preferably rounded and cosmetically shaped for insertion into the ear. The position of microphone component  102  behind faceplate  104  is illustrated by dashed lines. Ports  108  and  110  may be seen, located behind screens  118  and  116 , respectively. Toggle switch  124  of switch assembly  120  is located on the outside of faceplate  104  for access by the user. A volume control  146  may be further included to control the sensitivity of the hearing instrument. For example, volume control  146  may comprise a user tunable potentiometer, operatively connected to electric circuit  140  and/or receiver  142  for control the flow of electric current therein.  
         [0027]     While the invention has been described by illustrative embodiments, additional advantages and modifications will occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to specific details shown and described herein. Modifications, for example, to the layout of the hearing instrument device components and their spacing, may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention not be limited to the specific illustrative embodiments, but be interpreted within the full spirit and scope of the appended claims and their equivalents.