JPS6025706Y2 - Recording disc playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a recording disc reproducing device used in a video disc reproducing device.

A disk (rotating recording medium) used in a video disk playback device has a spiral recording line groove centered on its axis on its surface, and PCM (pulse code modulation) video information is recorded at the bottom of this groove. This is what I did.

As shown in FIG. 1C, this information signal is formed in a spiral groove on the surface of the disk 11 in an intermittent series, and these grooves are called pits and are shown as grooves 14 in FIG.

Its cross section is a groove 14 with opposing side walls 12 and 13 perpendicular to the surface of the disk 11, as shown in FIG. 1a.

When picking up information, a laser beam is irradiated to the bottom of the groove 14, that is, in a direction perpendicular to the information signal, and the reflected light is received.The intensity of the reflected light is detected by a detector 10 using a photoelectric conversion element. This is done by converting it into an electrical signal.

Therefore, at the bottom of the groove 14, PCM video information is recorded as a combination of a light transmitting part and a reflecting part.

However, with the above-mentioned disk, as shown in FIG. 1, the direction of the reflected light may be shifted due to the inclination or warpage of the disk surface, and the reflected light may not enter the detector normally.

The present invention was devised in view of the above circumstances, and it is an object of the present invention to provide a recording disk reproducing apparatus that can maintain the direction of reflected light in a stable direction.

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 2 and 3.

That is, 15 shown in FIG. 2 is a video recording disk body, and this disk body 15 is provided with a continuous spiral groove 16 centered on its axis.

As shown in FIG. 2C, this groove 16 has a V-shaped cross section with an angle of 90 degrees, and forms opposing inclined surfaces 17.17.

Further, on either side of this inclined surface 17, a video information signal is provided as a pit in a groove 24, as in the conventional case.

Incidentally, either one of the inclined surfaces 1 on which the video information signal is provided
The inclined surface facing 7 is used as a re-reflecting surface for laser light (described later), but it is also possible to provide video information signals on both inclined surfaces and use the opposing surfaces as re-reflecting surfaces. .

The flat surface of the disk on the outer periphery other than the groove 16 is a rough surface 20 with fine irregularities, etc., and is formed so that when light is incident thereon, the incident light is diffusely reflected.

A pickup means 18 is provided for such a disk 15.
The light irradiated from above is irradiated diagonally from above onto the inclined surface 17 on which the video information signal is recorded, as shown in FIGS. 2a and 2b.

That is, the pickup means is disposed in a direction perpendicular to the surface of the disk 15 (vertical direction) or in a diagonal direction with respect to the inclined surface 17.

Conventionally, laser light is directed in a direction perpendicular to the video information signal (
However, according to the present application, the laser beam is irradiated obliquely with respect to the video information signal.
It has two major characteristics.

In a recording disk reproducing device having such a configuration, the laser beam that illuminates the video information signal provided on one inclined surface is reflected by that surface, and the video information signal provided on the opposite surface is not recorded. It is re-reflected on the inclined surface and returns to the pickup means 18.

That is, since the opposing inclined surfaces are formed at an angle of 90 degrees, the incident light and the re-reflected light are always set in the same direction.

Therefore, although the pickup means 18 of the present application has been described as being provided in the vertical direction perpendicular to the disk surface, the groove 16 is shaped like a square with an angle of 90 degrees so that the incident light always returns in the same direction as the reflected light. The pickup means 18 can irradiate the disk surface not only vertically but also obliquely.

In other words, if the 90 degree V-groove is irradiated regardless of the position of the pickup means, the re-reflected light will always return to the position of the pickup means.

As a recording means, a method using a coating on the inclined surface of a reflective member or a method using a light transmitting part and a remaining part is used to convert the electrical video signal into PCM so that the change in the light reflection intensity of the inclined surface 17 corresponds to the PCM signal. Be taken.

Therefore, when the inclined surface 17 is irradiated with, for example, a laser beam from the pickup means 18 and a signal is picked up by the reflected light, as shown in FIG. When it hits the pick-up means 18, it is always reflected by the opposite inclined surface.
Light with the same phase is incident on the two.

Furthermore, as shown in FIG. 2, even if the disk surface is tilted, if the light is irradiated into the groove 16, the reflected light is always set to be parallel to the incident light, so that it always enters the pickup means 18. Ru.

This means that the angle of the inclined surface 17 of the groove 16 is opposed to V
It depends on the reason why it was set in the shape of the letter.

Furthermore, if a part of the light emitted from the pickup means 18 is emitted outside the groove 16, the emitted surface is formed into a rough surface, and the emitted light from the rough surface is diffusely reflected, which may have an adverse effect. It becomes less.

Furthermore, in the example shown in FIG. 3, the angle of the inclined surface 17 of the groove 16 is changed, but if the angle of the V-shaped opposing surface is set to 90', the same effect as described above will be produced. .

The above-mentioned video recording disk of the present invention can greatly improve its pickup action compared to the one shown in FIG. 1 even if the disk is warped or tilted in the mounted state.

Further, unnecessary reflected light is also less likely to interfere with the detection section, making it possible to obtain a high-quality reproduction signal.

Furthermore, the structure shown in FIG. 2 can also reduce the influence of external light.

As described above, the present invention can provide a recording disk reproducing apparatus that can maintain the direction of reflected light in a stable direction.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional video recording disk, FIG. 2 is a cross-sectional view showing an embodiment of the recording disk reproducing apparatus of the present invention, and FIG. 3 is a cross-sectional view of another embodiment of the disk according to the present invention. It is a diagram. 15.15'...Video recording disc body, 1
6... Groove, 17, 17'... Inclined surface,
18...Pickup means.

Claims (2)

[Scope of utility model registration request] (1) The cross section of the recording line groove formed in a spiral shape is set at an angle of 9
A disk having a 0 degree V-shape with an information signal recorded on at least one inclined surface of the V-shape, and one inclined surface of the disk on which the information signal is recorded are irradiated with a laser beam from a direction perpendicular to the disk surface. and pickup means for re-reflecting the reflected light onto mutually opposing inclined surfaces and receiving the re-reflected light at the irradiation position, and the irradiated reflected light always returns to the irradiation position. Device. (2) The recording disk reproducing apparatus according to claim 1, wherein the outer peripheral surface of the groove is roughened to diffusely reflect the irradiated light.