In-canal hearing aid

An in-canal hearing aid adapted to fit within the auditory canal of a wearer comprising

• a generally cylindrical member including a resilient stretchable outer layer for contacting the walls of the auditory canal, and an adjustably expandable member disposed within said outer layer for changing the diameter of said outer layer without significantly changing the length of the cylindrical member;
• hearing aid amplifying means disposed within said generally cylindrical member and including power source means, audio amplifier means, an input audio transducer disposed at one end of said generally cylindrical member and coupled to an input of said audio amplifier means, an output audio transducer disposed at the other end of said generally cylindrical member and coupled to an output of said audio amplifier means, and means for adjusting the gain of said audio amplifier means;
• and
• adjusting means extending from the one end of said generally cylindrical member for selectively expanding said adjustably expandable member such that the generally cylindrical member fits snugly in the wearer's auditory canal;
• said adjustably expandable member including an accordian spring member having a free end, another end anchored to said outer layer at said other end of said generally cylindrical member, and a plurality of occlusions disposed between said ends.

An in-canal hearing aid adapted to fit within the auditory canal of a wearer comprising

• a generally cylindrical member including a resilient stretchable outer layer for contacting the walls of the auditory canal, and an adjustably expandable member disposed within said outer layer for changing the diameter of said outer layer without significantly changing the length of the cylindrical member;
• hearing aid amplifying means disposed within said generally cylindrical member and including power source means, audio amplifier means, an input audio transducer disposed at one end of said generally cylindrical member and coupled to an input of said audio amplifier means, an output audio transducer disposed at the other end of said generally cylindrical member and coupled to an output of said audio amplifier means, and means for adjusting the gain of said audio amplifier means;
• and
• adjusting means extending from the one end of said generally cylindrical member for selectively expanding said adjustably expandable member such that the generally cylindrical member fits snugly in the wearer's auditory canal;
• and
• switching means for coupling said power source means to said amplifier means, said switching means being actuated by said adjusting means, such that said switching means are turned on when said wearer actuates the adjusting means to expand said expandable member.

An in-canal hearing aid adapted to fit within the auditory canal of a wearer comprising

• a generally cylindrical body insertable into the canal and selectively radially expandable to fit snugly in the canal;
• hearing aid amplifying means disposed within said generally cylindrical body and including power source means, audio amplifier means, an input audio transducer disposed at one end of said generally cylindrical body and coupled to an input of said audio amplifier means, an output audio transducer disposed at the other end of said generally cylindrical body and coupled to an output of said audio amplifier means, and digital gain control means for selectively controlling the gain of said audio amplifier means at the option of the wearer;
• and
• adjusting means disposed at said one end of said generally cylindrical member and coupled to said digital gain control means so that the user can selectively increase or decrease the gain of the audio amplifier means by touching the adjusting means;
• said audio amplifier means including a preamplifier followed by a power amplifier, and said gain control means including a digital touch feedback circuit having an input coupled to an output of said power amplifier, an output coupled to an input of said power amplifier, and a touch control terminal coupled to said adjusting means;
• said digital touch feedback circuit including touch means generating a pulse signal while said wearer touches said adjusting means, pulse generating means providing counter pulses during said pulse signal, counter means selectively counting said counting pulses up or down, and feedback circuit means responsive to the count on said counter means to provide a version of the amplified signal from the output of said power amplifier to the input thereof as a feedback signal;
• said counter means having a plurality of binary count terminals, a clock input terminal coupled to said pulse generating means, and an up/down control terminal;
• said feedback circuit means including a bilateral switch circuit having a plurality of inputs, a like plurality of outputs, and a like plurality of control terminals each coupled to a respective one of said binary count terminals, with load resistor means being coupled to either of said inputs and said outputs, and a plurality of progressively-valued resistors being coupled respectively to other of said inputs and said outputs of the bilateral switch circuit.