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JPH05120725

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Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
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DESCRIPTION JPH05120725
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
pickup capable of reproducing a record optically as well as a noncontacting optical disc by using
a semiconductor laser as a light source.
[0002]
2. Description of the Related Art FIG. 2 is a view for explaining a conventional record
reproducing apparatus, in which 1 is a pickup, 2 is a needle for reproduction, 3 is a record board,
4 is a recording V groove, 5 is a post, 6 Is a tone arm, 7 is a motor, and 8 is a turntable. FIG. 3 is
a partially broken perspective view showing the details of the pickup 1.
[0003]
The pickup 1 is a portion where the needle 2 comes in contact with the recording V groove 4 of
the record board 3 and picks up a sound signal as the name indicates. The pickup 1 is fixed to
the tip of a tone arm 6 which can be freely swung with a support 5 as a fulcrum. In addition, the
rotation of the recording board 3 is given by a turntable 8 which uses a motor 7 as a drive
source. As for the needle 2, the phonograph invented by Edison uses bamboo, and then, in the
era of monaural sound, a metal needle was used, but from the age of stereo recording and
reproduction, it extends from inside the electromagnetic coil It changed to the thing of the
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structure which attached the needle of the jewelry tip to the cantilever tip of the metal pipe. The
left and right wall surfaces of the recording V groove 4 of the rotating recording disc 3 are
abraded with the needle 2 of the jewelry chip, and the vibration of the needle 2 generated
thereby is divided into left and right electric components and taken out as reproduction signals.
[0004]
The major drawback of the record reproduction by these stylus type pickups 1 is that the
recording V-groove 4 is scraped by the needle 2 and the recording source is worn out and
reproduced in proportion to the number of reproductions The sound is to deteriorate. The pickup for metal needles is structurally heavy, so the load and needle pressure applied to the needle
are excessive, and with the needle of the jewelry tip, the hardness of the jewelry is in spite of the
use conditions where the needle pressure is reduced to the order of grams. In addition, because
the tip shape is high and the tip shape is sharp, a relatively soft material such as Bakelite or a
plastic record disc is scraped off by any of the needles, which can not be avoided by these
regeneration methods. It was a drawback.
[0005]
With the advent of a method for contactlessly reproducing light from disc sources such as
compact discs and laser discs without solving these problems, records and record needles have
hardly been produced at present. However, the number of vinyl records owned by enthusiasts is
considered to be considerable, and it is necessary to worry about the deterioration of sound
quality due to wear if it can be easily reproduced without contact by light as well as compact
disks and laser disks. In addition, since there is no noise at the time of reproduction due to
scratching of the needle, the reproduction characteristics of the record board are dramatically
improved.
[0006]
The object of the present invention is to solve the problem of abrasion occurring in the recording
V groove of the recording board by reproducing the recorded contents of the record without
contact as in the case of the optical disc, and to obtain a reproduced sound with high S / N ratio.
To provide.
[0007]
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SUMMARY OF THE INVENTION The optical pickup for recording according to the present
invention irradiates beam light individually to both wall surfaces forming the recording V groove
of the recording board at a fixed distance from the recording board surface. Two single-beam
semiconductor lasers arranged, a light-receiving element arranged at a position where the beam
reflected light from both wall surfaces can be received separately, and a tip arranged in the
vicinity of these and rubbing only the bottom of the recording V groove And a guiding needle of
a shape.
And not stereo reproduction but monaural reproduction.
[0008]
Also, a U-shaped semiconductor laser is used in place of the single beam semiconductor laser.
Furthermore, the guide needle is made of at least the tip portion of a softer material than the
record board material.
[0009]
Further, the guide needle is configured by bundling a plurality of brushes in a brush shape.
[0010]
In the present invention, the guide needle rubs and guides the bottom of the recording V groove
of the rotating recording disc, and light from two light sources using a semiconductor laser
(hereinafter referred to as LD) is recorded on the recording disc. The recording V-shaped groove
is separately applied to both wall surfaces, each reflected light is received by a light receiving
element (hereinafter referred to as PD), the intensity is converted into a frequency signal, and
stereo sound is reproduced.
And monaural reproduction can be performed in the same way.
[0011]
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In addition, the U-shaped semiconductor laser emits beam light from two beam light emitting
ends. Furthermore, the guide needle guides by rubbing the bottom of the recording V-groove
with the tip made of a soft material. In addition, since the plurality of needles are bundled in a
brush shape, the bottom of the plurality of recording V-grooves is rubbed to provide a stable
guide.
[0012]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is a principle view showing
an embodiment of the present invention using a micro lens attached U-shaped LD having two
beam light emitting end faces as a light source. 9 is a U-shaped LD, 10 is a beam light 11 is an
emission end face of beam light, 12 is a condensing micro lens, 13 is a PD, 14 is a guide needle,
15 is an electric circuit for LD / PD drive and light signal extraction, and 16 is a pickup structure.
The numbers other than the explanation are the same as those in FIG. If the configuration of the
record reproducing apparatus is the same as that shown in FIG. 2, the pickup 1 according to the
present invention can be attached to the tip of the tone arm 6 as in the conventional pickup.
[0013]
The U-shaped LD 9 is an emitting end face 11 of the light beam and a U-shaped light beam 10 so
that the emitted two light beams 10 individually individually hit each of the wall surfaces of the
recording V groove 4 having a V-shaped cross section of the recording disc 3 The bending angle
of the resonator is formed. In addition, a condensing microlens 12 is formed in front of the
emission end face 11 of the beam light. The U-shaped LD 9 having such a structure is in the
tracking direction so that both emission end faces 11 straddle the recording V groove 4 and that
light reflected by the recording V groove 4 does not return to the U-shaped LD 9 It is fixed at an
angle.
[0014]
The recording V-groove 4 spirally inscribed on the surface of the record board 3 has a V-shaped
cross section which is constant at about 90 degrees in the case of stereo recording, but has an
uneven shape of width and waviness in the tracking direction In order to change, the two light
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beams 10 emitted from the U-shaped LD 9 are deflected in the tracking direction when they are
reflected by the recording V-groove 4 respectively. Two PDs 13 are disposed at positions where
the reflected beam reflected light can be received separately. A guide needle 14 is disposed in the
vicinity of the U-shaped LD 9 and PD 13 which serves as the conventional reproducing needle 2
of FIG. 1 by light emission and light reception. As in the case of the conventional reproduction
needle 2, by mechanically scanning the recording V groove 4 with the guide needle 14, the beam
light 10 emitted from the U-shaped LD 9 in which the guide needle 14 and the fixed base are the
same is It is guided to irradiate the both wall surfaces of the recording V groove 4 constantly.
However, at least the tip side of the needle is formed of plastic softer than the recording disc
material, in order to prevent the V wall surface of the recording source from being scraped, as in
the case of using the conventional reproduction needle 2 . The whole may be made of a soft
material, or another material coated with a soft material. If a plurality of needles are used in the
form of a brush instead of one needle so that adjacent recording V-grooves 4 can be
simultaneously scanned, stable guiding can be performed without reducing the rigidity even if
the soft material is used with a smaller diameter. Further, in the case of metal, the V wall surface
can be protected if it is not in contact with the V wall surface of the recording V groove 4 and has
a sharp tip shape contacting at the V bottom portion so that only the V bottom portion is worn.
As described above, the guide needle 14 serving to guide the light beam 10 to the recording V
groove 4 keeps the close gap formed by the light emitting facet 11 and the recording V groove 4,
that is, the focal length constant. It becomes a guard which protects the character LD9 and PD13
from breakage. Further, by arranging on the front side of the tracking, it has a function of
removing dust and dirt attached by static electricity or the like from the recording V groove 4.
Even if there is a deformation such as a warp on the record board 3, it is possible to reliably
follow and keep the focal length constant.
[0015]
Although not shown in the drawing, the guide needle 14 can be used to adjust the gap between
the U-shaped LD 9 and the recording V-groove 4 (focal length adjustment) and relative
positioning between the U-shaped LD 9 and the guide needle 14. There is a needle position fine
adjustment mechanism.
[0016]
As described above, the U-shaped LD 9, PD 13, guide needle 14, and LD / PD drive / light signal
extraction electric circuit 15 are fixed to the pickup structure 16 with the mutual positional
relationship to satisfy the function and performance. Therefore, two light beams 10 from the Ushaped LD 9 at a position brought into contact with the rotating record disc 3 are continuously
irradiated to the recording V groove 4 of the record disc 3 and two pieces of reflected light are
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two Can be reproduced as a clear stereo sound by converting the intensity of the light into a
frequency signal.
In the calculation, it is possible to reproduce frequencies from the low frequency range to about
30,000 Hz, and it is most suitable for reproducing music records that occupy a large percentage.
[0017]
By separately placing the LD / PD drive / light signal extraction electric circuit 15 at the
arrangement destination of the motor 7, etc., the pickup 1 can be further miniaturized.
[0018]
Although two beams of light beam 10 of LD 13 are necessary for stereo reproduction, if normal
products of single beam light are used instead of U-shaped LD 9 described here, two recording Vgrooves 4 are respectively recorded. It may be made to face and be fixed to the V wall surface of.
In addition, since each beam light 10 must have a spot diameter of a size that fits on one wall
surface of the recording V groove 4, an LD other than the one on which the condensing
microlens 12 is formed like the U-shaped LD 9 In the case of incorporating, it is necessary to
squeeze to a required spot diameter through a small condenser lens or the like.
[0019]
Although all the embodiments described above are for stereo reproduction, the present invention
can also be applied to monaural reproduction. If monaural sound may be reproduced, only one
LD and one PD 13 are sufficient, and the spot diameter of the light beam 10 is also allowed to be
close to the width of the recording V-groove 4 larger than in stereo reproduction. The use of light
sources is easier than in the case.
[0020]
Although the life of the pickup 1 is greatly improved as compared with the conventional product,
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the guide needle 14 wears relatively quickly because the use mechanism is the same as the
conventional reproducing needle 2. However, replacement of only the guide needle 14 can be
easily performed. On the other hand, with regard to replacement with a new one due to
deterioration of the LD, the LD / PD is unitized integrally, and this can be detached from the
pickup structure 16 and lead wires can be separated at the connector portion It can be done
easily.
[0021]
When the record reproducing apparatus is configured using the pickup of the present invention,
by combining the optical disc into a combined type that can also reproduce an optical disc, the
apparatus can be made more versatile at an economical price.
[0022]
As described above in detail, according to the present invention, the light beam is individually
applied to both the wall surfaces forming the recording V groove of the recording board at a
constant distance from the recording board surface. Two single-beam semiconductor lasers, lightreceiving elements arranged at positions where the beam reflected light from both wall surfaces
can be received separately, and a tip shape arranged near these and rubbing only the bottom of
the recording V-groove Since it has a guide needle, it emits light beam from the LD brought close
to the rotating record board to the record recording groove, receives the reflected light by PD,
converts the intensity of light into frequency signal and reproduces it as sound Therefore, unlike
conventional pickups for stylus type records, mechanical force for reproduction does not act on
the record board.
As a result, since no wear occurs in the record recording groove, there is no deterioration in
sound quality no matter how many times the optical disc is reproduced, the reproduction life of
the record is dramatically improved.
[0023]
Further, since the noncontact reproduction is performed, the noise generated in the conventional
stylus type is removed, and the S / N ratio can be improved. Further, by using LD and PD for the
light source and the light receiving portion, the size can be greatly reduced as compared with the
conventional pickup, and the life can be prolonged.
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[0024]
Furthermore, if a U-shaped semiconductor laser is used, it is possible to use a single unit as a
light source. And it can be used not only for stereo reproduction but also for monaural
reproduction. In addition, since the guide needle is formed of a material softer than the recording
disc material at least on the tip side, the recording V groove is not cut. Furthermore, since the
guide needle is composed of a plurality of needles, the overall rigidity is increased, and a stable
guide can be performed.
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