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Description  |
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FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to a radio transmitter and receiver device
having a head band, one end of which is provided with a transmitting
microphone and the other end provided with a receiving speaker, and more
specifically to a radio transmitter and receiver device in which the
transmitting microphone of a bone transmission type is employed so that a
clear communication of radio conversation may be accomplished without
picking up noises from the transmitting side.
For conversation between a plurality of persons who are at remote locations
from each other, for example, at sites of construction work, places of
work and group activities in schools, transceivers of a hand-free voice
control type are widely used. Also, for conversation between a specific
student and a teacher through a master unit and a daughter unit of a
studying apparatus for foreign language, a transmitter and receiver device
in which a speaker and a microphone are mounted on a head band is used as
such apparatus.
The transmitter and receiver device in which a speaker and a microphone are
integrally mounted on a head band is disclosed, for example, in U.S. Pat.
No. 4,138,598. The transmitter and receiver device in said U.S. Patent
has a speaker placed in contact with both ends of a head band so as to
block the ears, and the other end of a bar having a microphone mounted on
one end thereof is pivotably mounted on one end of the head band. In such
a transmitter and receiver device, voice sounds emitted from the user's
mouth and all kinds of noises resulting from external environments, for
example, noises generated from architectural machines and the like, enter
the microphone. As a consequence, a person who receives the voice input
receives voice sounds which contain; these noises thereby making it
difficult to discriminate the voice sounds. That is, one receives voice
sounds which are poor in SN (signal-to noise) ratio thereby causing
listener fatigue. Therefore, for example, in the site of work where
industrial machines and civil engineering machines are driven, there has
been posed a problem in that such a transmitter and receiver device fails
to achieve good function in business conversation. In a transceiver using
such a transmitter and receiver device, there has been posed a problem in
that the above-described noises cause switching control of transmitting
and receiving to make mistake, failing to make conversation. In other
words, there has been a problem in that in the transmitter and receiver
device which performs transmitting and receiving, receiving becomes
impossible by deterioration of the ratio of voice sounds to noise sounds
on the transmitter side.
In order to improve these disadvantages, a so-called bone transmission type
microphone, which detects a voice oscillation of an external auditory
canal transmitted through bone tissue of a head from the mouth, has been
recently developed. Such a bone transmission type microphone is disclosed,
for example, in U.S. Pat. No. 4,150,262. The bone transmission type
microphone comprises a casing having an insert inserted into an external
auditory canal, a retainer secured within said casing, a piezo-electric
element having one end secured to said retainer and the other end
positioned within the insert, and a lead wire for providing a polarization
voltage from the piezo-electric element. With this structure, the
oscillation of the external auditory canal generated when a voice sound is
emitted is transmitted to the piezo-electric element, and the polarization
voltage may be obtained through the lead wire from the piezo-electric
element in accordance with the generation of strain as the result of said
oscillation. This voltage is again regenerated as voice through an
amplifier or the like, and subjected to necessary correction of voice,
which is put out to the speaker to catch the voice. Thus, only clear voice
can be received without introducing external noises into the microphone
together with the aural signal.
If such a bone transmission type microphone is incorporated into the
transmitter and receiver together with a head phone as described above,
both the left and right ear holes are blocked by the head phone and
microphone, respectively. If this device is used at the site of
construction work, external alarm, noises of movement of machines or the
like do not directly enter the ears, and this poses a very dangerous
condition.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a radio transmitter and
receiver device which can make response by radio while receiving clear
voice sounds without blocking both ears, while improving the disadvantages
noted above with respect to the prior arts.
In accordance with the present invention, there is provided a radio
transmitter and receiver device comprising a hair band held on the head of
a user, a speaker mounted on one end of said hair band and positioned so
as to block one of the ears, a bone transmission type microphone mounted
on the other end of the hair band and placed in contact with a side head
portion at the rear of the other ear, and an antenna with matching means
mounted on the head band.
In accordance with a preferred embodiment of the present invention, the
bone transmission type microphone comprises a pad in contact with the side
head portion, a diaphragm for fixing said pad, and a piezo-electric
element adhered to said diaphragm. Voice on the transmitting side picks up
aural oscillations transmitted to the side head portion by the diaphragm.
The antenna with matching means is mounted on the hair band on the speaker
side.
In the radio transmitter and receiver device of the present invention, it
is possible to make transmitting and receiving conversation without
blocking both ears and without interference of environmental noises around
the transmitter side to make possible the clear transmitting and receiving
of voices. Further, external voice sounds or noises can be heard through
the ear on the microphone side, and therefore, it is possible to
simultaneously make normal conversation with a person who does not wear
this device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a headset used with the perspective view showing one embodiment
of a headset used with the radio transmitter and receiver device in
accordance the present invention.
FIG. 2 is a view showing the wearing condition of the headset shown in FIG.
1.
FIG. 3 is a sectional view showing one embodiment of a bone transmission
type microphone in FIG. 1.
FIG. 4 is a block diagram showing one embodiment of an electric control
circuit.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, a headset of the radio transmitter and receiver device in
accordance with the present invention is generally indicated as at 11. In
the headset 11, retainer members 13 formed of synthetic resin or the like
having a low coefficient of friction are mounted on both ends of a head
band 12 formed of an elastic material. The other end of a sliding rod 15,
on one end of which is mounted a head phone type or earphone speaker 14
positioned so as to block an ear hole, is slidably retained on one
retainer member 13 with a certain degree of contact resistance. The other
end of a sliding rod 16, on one end of which is mounted a bone
transmission type microphone 17, is slidably retained on the other
retainer member 13. A locking piece 18 to be hooked on the upper portion
of the ear is projected on the bone transmission type microphone 17. On
the other hand, matching means 19 for delivering and receiving high
frequency energies in spaces for a transmitter and a receiver necessary
for radio communication is mounted on the earphone speaker 14. A
transmitting and receiving antenna 20 is mounted on the matching means 19.
When the device is used, the antenna is raised to a high position to
enhance the effective value of the antenna.
The bone transmission type microphone 17 comes into contact with a side
head portion at the rear of the other ear when the head band 11 is put on
the user'head and the earphone speaker 14 comes into contact with one ear
as shown in FIG. 2. The locking piece 18 is provided to make the locking
position of the microphone 17 accurate and stabilized. The bone
transmission type microphone 17 comprises, as shown in FIG. 3, a synthetic
resin housing 21, of which the side thereof in contact with the side head
portion of the user is open, and a flexible diaphragm 22 provided so as to
block an opening of the housing 21. A piezo-electric crystal element 23 in
which strain is generated as the diaphragm 22 oscillates, is adhered to
the side of the flexible diaphragm 22 on the side of the housing 21. This
piezo-electric element 23 is polarized by generation of strain, and the
polarization voltage is removed from the diaphragm 26 and piezo-electric
element 23 through a lead wire 24. A projection 26 is secured to the other
side of the diaphragm 22, said projection 26 being integrally formed on a
pad 25. The pad 25 is placed in close contact with the side head portion
of the user at the rear of the ear, and therefore, one side 25a thereof is
formed into a curved surface having a curved contour. Since the principle
of the bone transmission type microphone is described in detail in the
aforementioned U.S. Pat. No. 4,150,262, an explanation thereof will be
omitted.
FIG. 4 is a block diagram showing an electric structure employed in the
present invention. A signal from the bone transmission microphone 17 is
applied to a transmitter circuit. The transmitter circuit comprises an
amplifier 31 for correcting an amplitude level characteristic within an
aural band to amplify a signal from the microphone 17, a carrier wave
oscillator 32 for oscillating a carrier wave, an FM modulator 33 for
modulating a carrier wave from the carrier wave oscillator 32 by an output
signal of the amplifier 31, a buffer amplifier 34, a power amplifier 35
and the like. On the other hand, the receiver circuit comprises a high
frequency amplifier 36 for amplifying a signal received from the antenna
20, a local oscillator 37, a mixer circuit for mixing signals from the
amplifier 36 and oscillator 37, an intermediate frequency amplifier 39, a
detector circuit 40 and a low frequency amplifier 41. An output of the
amplifier 41 is connected to the speaker 14. The antenna 20 is connected,
for use in common to transmitting and receiving, to an antenna maneuvering
switch 42 through the antenna matching means 19. Since these elements are
the same as a circuit for a conventional transceiver, a detailed
description thereof will be omitted. The aforesaid transmitter and
receiver circuit is housed in a casing (not shown), which is in turn held
by a belt or the like of a user.
As described above, in the bone transmission type microphone 17, the voice
sound generated within the mouth of a person is formed into oscillation,
which is transmitted to the bone tissue of the side head portion, and said
oscillation is transmitted with high sensitivity to the diaphragm 22
through the pad 25 in contact with the side head portion. Therefore,
strain is generated in the piezo-electric crystal element 23 in accordance
with the oscillation of the diaphragm 22, and polarization voltage
corresponding to said strain is produced and applied to an input circuit
of the amplifier 31 in the transmitter circuit through the lead wire 24.
This voltage is amplified by the amplifier 31 and is received by another
receiver by radio from the antenna 20 through the transmitter circuit. The
other receiver can receive clear voice sounds without receiving at all
environmental noises in the periphery of the transmitting person. In
addition, in the transmitter and receiver device of the present invention,
both ears are not blocked as described above, and therefore, the user can
hear other voices and sounds in the vicinity of the device. Thus, it is
possible to send clear aural wave without being impaired by noises
generated during the civil engineering work, and a danger involved in the
user such as the conventional case wherein both ears are blocked can be
avoided.
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