ACOUSTIC SIGNAL OUTPUT DEVICE

1 . An acoustic signal output device worn on an auricle, comprising:

a housing that emits an acoustic signal; and

a wearable portion that holds the housing and is configured to be worn on the auricle,

wherein the wearing portion includes a fixing portion including a concave inner wall surface configured to be fitted into an upper portion of the auricle, and a shielding wall configured to cover only a part of the auricle when a side of the inner wall surface of the fixing portion is fitted into an upper portion of the auricle.

2 . The acoustic signal output device according to claim 1 ,

wherein the shielding wall is formed in a shape that opens a lower portion of the auricle to an outside while covering an upper portion of the auricle when a side of the inner wall surface of the fixing portion is fitted into an upper portion of the auricle.

3 . The acoustic signal output device according to claim 2 ,

wherein the shielding wall is formed in a shape that further opens a part of an upper portion of the auricle to an outside when a side of the inner wall surface of the fixing portion is fitted into an upper portion of the auricle.

4 . The acoustic signal output device according to claim 1 , further comprising

a driver unit that emits a first acoustic signal to one side and emits a second acoustic signal to another side,

wherein a wall portion of the housing is provided with a single or plurality of first sound holes for leading out the first acoustic signal emitted from the driver unit to an outside and a single or plurality of second sound holes for leading out the second acoustic signal emitted from the driver unit to an outside, and

the first sound holes are arranged on an inner side of the shielding wall and the second sound holes are arranged on an outer side of the shielding wall,

in a case where the first acoustic signal is emitted from the first sound holes and the second acoustic signal is emitted from the second sound holes, an attenuation rate of the first acoustic signal at a second point with reference to a predetermined first point, where the first acoustic signal arrives at the first point and the second point is farther from the acoustic signal output device than the first point, is designed to be

equal to or less than a predetermined value smaller than an attenuation rate due to air propagation of an acoustic signal at the second point with reference to the first point, or an attenuation amount of the first acoustic signal at the second point with reference to the first point is designed to be

equal to or more than a predetermined value larger than an attenuation amount due to air propagation of an acoustic signal at the second point with reference to the first point.

5 . The acoustic signal output device according to claim 4 ,

wherein a part of the shielding wall is provided with an opening portion that partially opens a portion of the auricle to an outside when an upper portion of the auricle is fitted into a side of the inner wall surface of the fixing portion, and

an opening area per unit area of the second sound holes arranged on a side where the opening portion is provided is larger than an opening area per unit area of the second sound holes arranged on a side where the opening portion is not provided.

6 . The acoustic signal output device according to claim 5 ,

wherein the opening portion is provided at a position where a lower portion of the auricle is opened to an outside and/or is provided at a position where a part of an upper portion of the auricle is opened to an outside when a side of the inner wall surface of the fixing portion is fitted into an upper portion of the auricle.