JPS5839560Y2 - optical recording or reproducing device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an apparatus for recording or reproducing data by projecting a light beam onto a disc-shaped recording medium, and more specifically, the present invention relates to an optical recording device in which the scanning position of the light beam can be easily detected. Or regarding a playback machine.

For example, when using a Philips video disc player, it would be convenient to be able to externally detect where the light beam is scanning, and several methods have already been proposed for detecting and displaying the scanning position. .

However, this method has disadvantages such as that the configuration of the detection and display device becomes complicated, and that the display location is specified.

In addition, it has been proposed to record address information in addition to the main information in the video disk player mentioned above to perform information retrieval, but tracking becomes impossible in high-speed feed conditions, The disadvantage is that it becomes impossible to detect.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical recording or reproducing device that can easily constitute a light beam scanning position detection device that does not rely on address information.

To achieve the above object, the present invention provides a disk rotation device for rotating a disk-shaped recording medium for recording or reproducing information in the form of concentric circles or spiral tracks, and a first light beam emitting in one direction. and a laser light source that emits a second light beam in the other direction opposite to the one direction, and the first light beam emitted from the laser light source is used as a recording or reproducing light beam to record the disc-shaped recording. an optical device for projecting onto a medium; a radial feed device for sending the laser light source and the optical device in the radial direction of the disk-shaped recording medium; The present invention relates to an optical recording or reproducing device comprising: a light beam detection device which uses two light beams to obtain a detection output corresponding to the radial feed of the laser light source and the optical device.

According to the above invention, the laser light source and the optical device are fed based on the second light beam emitted in the opposite direction to the first light beam for recording or reproduction emitted from the laser light source. Since a detection output is obtained, the detection of the radial feeding position, that is, the scanning position of the recording or reproducing light beam on the disk-shaped recording medium can be achieved with a relatively simple configuration.

Therefore, even if an address signal cannot be obtained from the recording medium, it is possible to know the address being scanned.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1 showing a disc player according to a first embodiment of the present invention, a disc 1 is, for example, 1800 r, p.
, m is provided as a disk rotating device.

The light beam projection device 3 shown surrounded by a dotted line consists of a laser light source 4 made of a He-Ne laser tube, a beam splitter 5, a λ plate 5a, an optical device 6, and a photodetector 3. The first light beam 8 passes through the beam splitter 5 and the ±λ plate 5a to an optical device 6 acting as a scanning head, where it is focused and projected onto the disk 1, and the reflected light beam is transmitted to the optical device 6. 1λ plate 5a,
The beam is configured to reach a photodetector 7 via a beam splitter 5.

The light beam projection device 3 as described above is guided by a guide shaft 9 extending in the radial direction of the disk 1, and
It is locked to an endless wire 0 extending in the radial direction of the disk 1.

Since the wire 0 is hung between a drive pulley 12 connected to the radial feed motor 1 and a driven pulley 13 provided at the inner peripheral position of the disk, the wire 0 moves following the rotation of the feed motor 1.

Further, the light beam projection device 3 moves following the movement of the wire 0.

The disk 1 fixed on the turntable 14 by the clamper 15 has a width of about 1 μm, a depth of about Tλ (here, λ is the wavelength of the laser beam), and a length of 1.5 μm, as shown in FIGS. 2 and 3. 5
Information such as a video signal or an audio signal is recorded on a spiral track 17 by FM using optical depressions or pits 16 of ~6 μm in diameter, and generally a transparent resin layer has an uneven surface corresponding to the pits 16 as shown in FIG. 18, a reflective film 19 that covers the uneven surface of the resin layer, and a protective film 20 that protects the reflective film.

In this embodiment, the television signal is recorded so that half a turn of the track 17 corresponds to one field, and one turn corresponds to one frame.

As shown by c, d, and e, addresses are recorded as digital signals during vertical blanking periods that exist every half cycle.

Since the diameter of the spot of the reproduction light beam 8 projected onto the track of the disk 1 as described above is larger than the width of the pit 16, when the light beam 8 is projected onto the pit 16, the reflected light within the pit and the pit Cancellation with external reflected light occurs and the reflected output becomes small, and when the light beam 8 is projected onto an area where there is no pit 16, no cancellation occurs and the reflected output becomes small.

Therefore, by detecting the intensity of the reflected light with the photodetector 7, the presence or absence of the pits 16, that is, information can be read.

In this embodiment, since the frame address signal is recorded during the vertical blanking period as described above, not only the output of the photodetector I is demodulated by the demodulation circuit 21 to obtain a reproduced television signal, but also the photodetector A frame address signal is obtained in the form of a binary encoded digital signal from an address detection circuit 22 connected to the circuit 7.

The output of the address detection circuit 22 can be input to one input terminal of the comparator 24 via the switch 23, and the program address signal from the program circuit 25 is input to the other input terminal of the comparator 24. During address search, the detected address signal applied from the address detection circuit 22 and the program address signal applied from the program circuit 25 are digitally compared, and when they match, a comparison output is generated and the feed motor 11 is controlled.

For example, if a command to stop at address 100 is generated from the program circuit 25, a digitized program address signal corresponding to address 100 is given to the comparator 24, and the movement of the light beam projection device 3 causes 10
When the frame at address 0 is read and a digitized address signal representing this address is detected by the address detection circuit 22, a match with the program signal is detected by the comparator 24, and the feed motor 11 is stopped. controlled.

The convex lens 26 provided in the light beam projection device 3 is a light beam conversion device for causing a change in the luminous flux corresponding to the movement of the light beam projection device 3 in the disk radial direction, and is a light beam converting device that changes the light beam in accordance with the movement of the light beam projection device 3 in the disk radial direction. In addition to the first light beam 8 generated, the second light beam 2r generated from the rear of the laser tube is converged.

The light beam 2γ that has passed through the convex lens 26 reaches the photodetector 30 via the microtransparent portion 29 of the light beam restriction plate 28.

The light beam limiting plate 28 and the photodetector 30 are fixedly arranged so that the second light beam 27 is perpendicularly incident thereon.

FIG. 4 is a drawing for explaining the detection of the scanning position, that is, the position of the light beam projection device 3. When the light beam projection device 3 is closest to the light beam limiting plate 28, the focus of the second light beam 27a is is the position of Fa, and the area of the spot on the light beam limiting plate 28 is relatively small.

Therefore, most of the light beam 27a reaches the photodetector 30 via the microtransparent portion 29, and a relatively large output can be obtained from the photodetector 30.

On the other hand, when the light beam projection device 3 moves to the farthest position from the light beam limiting plate 28, the second light beam 27b
In this case, the light beam is focused at point Fb, and the area of the spot on the light beam limiting plate 28 becomes smaller than in the case of the light beam 2γa.

Therefore, only a part of the light beam 27b can be detected by the photodetector 30, and the light beams 27a and 27 from the light source have the same intensity.
b is emitted, the detection output of the light beam 27b will be smaller than the detection output of the light beam 2γa.

The focusing position of the second light beam 27 changes between point Fa and point Fb in accordance with the movement of the light beam projection device 3, and the output of the photodetector 30 changes accordingly as shown in FIG. Change.

Therefore, the output of the photodetector 30 corresponds to the position of the light beam projection device 3, that is, the scanning position.

The output of the photodetector 30 is passed through an amplifier 31 to a display 32, which is used to display the scanning position in analog or digital form, and is converted into a digital signal by an analog-to-digital converter 33.

The address signal obtained from the A-D converter 33 is sent to the comparator 24 via the switch 23 when the address signal cannot be obtained from the address detection circuit 22 due to a high-speed feed state or the like.
and used for automatic search.

As is clear from the above, in the apparatus of this embodiment, scanning position detection is possible only by providing the convex lens 26, the limiting plate 28, and the photodetector 30, so that the apparatus configuration is simplified.

Furthermore, since it is obtained as an electrical signal, not only is there no restriction on the display location, but it can also be used for automatic search.

Next, a video disc player according to a second embodiment of the present invention will be described with reference to FIGS. 6 and 7.

However, since the configurations and functions of the components indicated by reference numerals 1 to 15.21 to 25.28.32.33 are the same as those indicated by the same reference numerals in FIG. 1, their explanations will be omitted.

In this second embodiment, a first convex lens 41 and a second convex lens 42 are fixedly arranged in the light beam projection device 3 as a light beam conversion device.

As is clear from FIG. 1, the relationship between the first convex lens 41 and the second convex lens 42 is such that the optical axis 4 of the first convex lens 41
1 a is translated by a predetermined amount δ with respect to the optical path of the second light beam 27 obtained from the right side of the laser light source 4 .

In other words, the light beam 27 is arranged so as not to pass through the center of the first convex lens 41 but through the lower side in FIG.

On the other hand, the second convex lens 42 is arranged so that its optical axis 42a substantially coincides with the first optical path of the light beam 27, and its front focus coincides with the rear focus F of the first convex lens 41. It is arranged so that

Therefore, the light beam 27 passes under the first convex lens 41 and reaches the upper side of the second convex lens 42, from where it obliquely enters the fixed and two-split photodetector 43.

The light beam 2γ' obtained by passing through the second convex lens 42
is a parallel light beam and is tilted, so if the lens 42 moves together with the light beam projection device 3, the beam spot moves up and down on the two-split photodetector 43, and the output of the first photodetector 43a changes. and the second photodetector 43b changes.

That is, when the light beam projection device 3 is closest to the photodetector 43, the spot 44a of the light beam 27' is biased on the photodetector 43 as shown in FIG. When the light beam projection device 3 is farthest away, a spot 44b is formed below the photodetector 43.

Further, at an intermediate position, the light is projected onto the dividing line of the photodetector 43, and the output of the differential amplifier 44 becomes zero.

Therefore, the positive and negative outputs are output from the differential amplifier 44 with the intermediate position being zero.
The position of the optical beam projection device 3, that is, the scanning position can be known from the output of the differential amplifier 44.

As is clear from the above, even in this device, the scanning position or the position of the light beam projection device 3 can be detected by simply providing the convex lenses 41, 42 and the photodetector 43, so the first embodiment A similar effect can be obtained.

Next, a video disc player according to a third embodiment of the present invention will be described with reference to FIG.

However, codes 1 to 15.28.43.43a143b14
The structure and function of the components indicated by 4 are the same as those indicated by the same reference numerals in FIG. 1 and FIG. 6, so the explanation thereof will be omitted.

In this third embodiment, the laser light source 4 is arranged at an angle of θ degrees with respect to the moving direction of the light beam projection device 3, thereby obtaining the light beam 27 that is obliquely incident on the photodetector 43.

Even in this case, the position of the light beam projection device 3 can be detected using exactly the same principle as the player of the second embodiment.

Although the display and search circuit is not shown, a circuit having the same configuration as that in FIG. 1 is provided.

Next, a video disc player according to a fourth embodiment of the present invention will be described with reference to FIG.

However, codes 1 to 15.28.43.43a143b, 4
The structure and function of the components indicated by 4 are the same as those indicated by the same reference numerals in FIG. 1 and FIG. 6, so the explanation thereof will be omitted.

In this embodiment, a mirror 51 is provided as a light beam conversion device, where the light beam 27 of the stake 2 is refracted and obliquely impinges on the photodetector 43.

Therefore, the light beam projection device 3 and the scanning position can be detected using the same principle as in the second and third embodiments.

Note that this display and search circuit is provided with a circuit having the same configuration as that of the 7X shown in FIG. 1, which is not shown.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments and can be further modified.

For example, it is also applicable to recording devices.

Further, in the first embodiment, the photodetector 30 may be made the same size as the light-transmitting portion 29, and the limiting plate 28 may be omitted.

[Brief explanation of the drawing]

FIG. 1 is a block front view showing a disc player according to a first embodiment of the present invention, FIG. 2 is a schematic plan view of a video disc, FIG. 3 is an enlarged sectional view of the video disc, and FIG. FIG. 5 is a graph showing the relationship between the position of the light beam projection device and the output of the photodetector in the player of FIG. 1, 6 is a block front view of a disc player according to a second embodiment of the present invention, FIG. 1 is an optical path diagram of the player of FIG. 6, and FIG. 8 is a photodetector and a photodetector of the player of FIG. FIG. 9 is a front view of a disc player according to a third embodiment of the present invention, and FIG. 10 is a front view of a disc player according to a fourth embodiment of the present invention. . In addition, in the symbols used in the drawings, 1 is a disk,
3 is a light beam projection device, 4 is a laser light source, 2C is a convex lens, 28 is a light beam limiting plate, 29 is a minute transparent part, 30 is a photodetector, and 32 is a display.

Claims (1)

[Claims for Utility Model Registration] ■ A disk rotating device for rotating a disk-shaped recording medium for recording or reproducing information in the form of concentric circles or spiral tracks; , a laser light source that emits a second light beam in the other direction opposite to the one direction; and the disk-shaped recording medium uses the first light beam emitted from the laser light source as a recording or reproducing light beam. a radial direction feeding device for sending the laser light source and the optical device in the radial direction of the disk-shaped recording medium; an optical recording or reproducing device comprising: a light beam detection device that obtains a detection output corresponding to the radial feed of the laser light source and the optical device using a light beam of the light beam; 2. The light beam detection device includes a convex lens arranged to be sent together with the laser light source by the radial direction sending device and disposed in the optical path of the second light beam, and a convex lens that travels through the convex lens. A light beam limiting plate having a microtransparent part fixedly arranged in the optical path of the second light beam, and a photoelectric converter that converts the light beam passing through the light beam limiting plate into an electrical signal. An optical recording or reproducing device according to claim 1 of the utility model registration claim. 3. The light beam detection device is arranged such that its optical axis is translated by a predetermined amount with respect to the optical path of the second light beam, and is arranged so that it is sent together with the laser light source by the radial direction sending device. a first convex lens, the optical axis of which is moved parallel to the optical axis of the first convex lens such that its optical axis coincides with the center of the optical path of the second light beam before entering the first convex lens; the first convex lens, and the first convex lens is arranged at a position where a plane including a rear focal point and a plane including a front focal point of the first convex lens coincide with each other, and is arranged to be sent together with the laser light source by the radial sending device. a second convex lens, and a two-split photoelectric converter that is fixedly arranged so that the second light beam obtained through the second convex lens is incident obliquely. The optical recording or reproducing device according to item 1. 4. The optical recording or reproducing device according to claim 1, wherein the light beam detection device is a two-segment photoelectric converter fixedly arranged so that the second light beam is incident obliquely. . 5. The light beam detection device includes a mirror that refracts the second light beam obliquely with respect to a feeding method by the feeding device, and a mirror that refracts the second light beam obliquely with respect to the feeding method by the feeding device, and 2. The optical recording or reproducing device according to claim 1, which comprises a fixedly arranged two-segment photoelectric converter.