JPS6216462B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a record disc detection device that optically and non-contact detects the presence or absence of a record placed on the turntable of a record player or the size of the record. The objective is to create a record disc that can start playing a record even if it is a transparent record by controlling the operation of the pick-up arm device reliably under control from the start operation. The object of the present invention is to provide a detection device.

Conventional configurations and their problems In general, so-called auto players equipped with a mechanism to control the movement of the pick-up arm require some method to preset the size of the record placed on the turntable, which requires the user to If the setting is incorrect or if a record is started without a record placed on the turntable, the playback stylus may fall onto the turntable and damage the playback stylus. Therefore, in order to prevent the above-mentioned malfunction or accidental damage to the playback stylus, we have developed a system that uses transparency of the turntable as a means to optically and non-contact detect the presence or absence of a record on the turntable and the size of the record. An optical record detecting device has been proposed that includes a combination of photoelectric conversion elements arranged under the hole and a light source arranged at a position higher than the turntable surface. However, such a record detecting device cannot correctly detect the existence and size of a record placed on a turntable if it is transparent. The drawback was that it was no longer possible to play records. In other words, when there is no record placed on the turntable, the operation is controlled so that the pick-up arm device does not move based on the detection results, or the operation is controlled so that the pick-up arm device moves up and moves but does not come down. Therefore, when a transparent record is placed on a turntable, the operation is controlled based on the same detection results as these, and in the end, the record cannot start playing. There was a problem.

OBJECTS OF THE INVENTION The present invention solves these conventional drawbacks, and makes it possible to reliably detect the presence or absence and size of a transparent record even when it is placed on it.

Structure of the Invention The present invention provides a main body of a record player including a turntable that is rotationally driven by a turntable shaft, and a post having either a light receiver or a light emitter at the tip is disposed near the turntable, and the record player Arranging the other of the light receiver or the light emitter in correspondence with each through hole corresponding to the record size provided on the turntable on the main body side,
Further, a light shielding member is provided at the tip of the post for selecting an optical coupling relationship between the light emitter and the light receiver depending on the size of the record placed on the turntable. In this way, even if the record placed on the turntable is transparent, the presence or absence and size of the record placed on the turntable can be detected by means of the light shielding member. Therefore, the operation of the pickup arm device can be controlled to ensure reliable performance from the start operation.

DESCRIPTION OF THE EMBODIMENTS FIGS. 1 and 2 show an embodiment of the record disc detection device of the present invention. In the figures, 1 is a record player body, and a turntable shaft 2 is provided on the top surface of the record player body, which is rotatably driven. It has a turntable 3. Further, on the upper surface of the record player main body 1, there is provided a pickup arm device 7 for playing a record 6 placed on the turntable 3. This pick-up arm device 7 has a cartridge 8 at its tip, and a tone arm 9 having a balance weight 5 at its rear end is swingably attached to a pedestal 10 provided on an arm base 11 on the upper surface of the record player body 1. It is designed to be moved by a main body of a driving device such as a motor (not shown). 13 is a post provided on the record player main body 1;
The driving device main body is provided at the tip of the post 13, and its operation is controlled by a record detecting device provided inside the record player main body 1.

The record disc detection device includes through holes 14a, 14b, 1 provided in the turntable 3 for detecting record discs of various sizes (30cm, 25cm, 17cm).
4c is provided with prisms 12a, 12b, 12c,
A light source 1 is placed under the prisms 12a, 12b, 12c.
5a, 15b, 15c are provided, while the above-mentioned post 1
A photoelectric conversion element 17 that is appropriately shielded from light by a light shielding member 18 is disposed at the tip of the photoelectric conversion element 3 . Here, the light shielding member 18 is formed into a cup shape as shown in FIG. 3, is fitted to the tip of the post 13, and is rotated by a V-shaped biasing spring 19 provided therebetween. It's becoming like that.

Further, V grooves 20a, 20b, 20c, and 20d into which the V-shaped biasing spring 19 is inserted are provided on the inner peripheral surface. On the other hand, the photoelectric conversion element 17 is provided at the tip of the post 13, and its lead wires 21a and 21b are inserted through the center hole of the post 13. As shown in FIG. 4, the light shielding member 18 has a through hole 16a through which all the light rays from the light sources 15a, 15b, 15c pass through the prisms 12a, 12b, 12c and enter the prisms 12a, 12c. 12b to the light sources 15a, 15b.
a through hole 16b for allowing only the light rays from to enter;
A through hole 16c for allowing only the light source from the light source 15a to enter through the prism 12a, and a through hole 16c for allowing only the light source from the light source 15a to enter through the prisms 12a, 12b, 12c.
Blind holes 16d for blocking all of the light rays from 5a, 15b, and 15c are provided at 1/4 dividing points of the circumference, respectively.

In a record disc detection device having such a configuration, when an opaque record disc 6 is normally placed on the turntable 3, the light shielding member 18 has its through hole 16a facing the record disc 6 on the turntable 3. The light sources 15a, 1
5b, 15c and the photoelectric conversion element 17 are shielded from light according to the size of the opaque record 6. In other words, when the opaque record 6 is 30 cm long, the presence or absence of the 30 cm record 6 and its size are detected by blocking all light with the record 6, and the opaque record 6 is 25cm
If it is, the outer one of the record discs 6 is unblocked and the inner two are blocked, thereby detecting the presence or absence of the 25 cm record disc 6 and its size. is 17
cm, the presence or absence of a 17 cm record 6 and its size can be detected by unblocking the two outer sides of the record 6 and blocking the inner one. Therefore, the operation of the pickup arm device 7 can be controlled to ensure reliable record performance from the start operation.

On the other hand, when a transparent record 6 is placed on the turntable 3, the light cannot be blocked by the record 6. It will be detected. Therefore, in such a case, the transparent holes 16b, 16c and the blind hole 16d of the light shielding member 18
is selected according to the size of the transparent record 6 placed on the turntable 3 to create a pseudo-opaque record placed on the turntable 3.
That is, in the case of a 30 cm transparent record disc 6, the blind hole 16d of the light shielding member 18 is selected to block all the light rays from the light sources 15a, 15b, and 15c, and in the case of a 25 cm transparent record disc 6, ,same
Light source 1 when a 25cm opaque record is placed
The through hole 16c of the light shielding member 18 is selected to have a size that allows substantially the same amount of light to enter the light beam from the light source 5a, and in the case of a 17 cm transparent record disc 6,
By selecting the through hole 16b of the light shielding member 18 to be sized to receive substantially the same amount of light as the light rays from the light sources 15a and 15b when the same 17 cm opaque record is placed, a transparent Even if it is a record disc 6, the operation of the pickup arm device 7 can be controlled so that playback of the record can be started reliably from the start operation in the same way as with an opaque record disc.

In the above embodiment, the record player body 1
Place the light source under the turntable 3, the tip of the post,
Although a photoelectric conversion element is provided, these light receivers and light emitters may be arranged interchangeably.

Effects of the Invention As described above, according to the present invention, a post having either a light receiver or a light emitter at the tip is provided in the vicinity of the turntable of a record player body equipped with a turntable that is rotationally driven by a turntable shaft. The other of the light receiver or the light emitter is arranged on the record player main body side corresponding to each through hole corresponding to the record size provided on the turntable, and the light emitter and the light receiver are arranged at the tip of the post. Since a light-shielding member is provided that selects the optical coupling relationship between the records according to the size of the record placed on the turntable, the record placed on the turntable is transparent. It is possible to detect the presence or absence of a pseudo-recorded record and to detect its size, even if the record is placed on the disc, and to control the operation of the pick-up arm device to ensure reliable performance from the start operation. be.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a record player equipped with a record detecting device of the present invention, and FIGS. 2, 3, and 4 are enlarged cross-sectional views of essential parts of the device. DESCRIPTION OF SYMBOLS 1... Record player main body, 2... Turntable shaft, 3... Turntable, 6... Record disc, 7... Pick up arm device, 12a,
12b, 12c...prism, 13...post,
15a, 15b, 15c... light source, 14a, 14
b, 14c, 16a, 16b, 16c...through hole,
17... Photoelectric conversion element, 18... Light shielding member, 19
...Biasing spring, 20a to 20d...V groove.

Claims (1)

[Claims] 1. A record player body equipped with a turntable rotationally driven by a turntable shaft has a post protruding near the turntable so that its tip extends to a higher position than the top surface of the turntable, and the turntable is attached to the tip of the post. Either a light emitter or a light receiver that illuminates the top surface or receives light from the turntable side is arranged, and at the same time, in each through hole corresponding to the record size provided on the turntable on the record player main body side. The other of the light receiver and the light emitter is arranged correspondingly, and the optical coupling relationship between the light receiver and the light emitter is arranged at the tip of the post, and the type or size of the record placed on the turntable is determined. A record disc detection device provided with a light shielding member for selection according to the type of record.