JPH0325341Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a playback device for an optical disc such as a so-called compact disc.

BACKGROUND ART An optical disk has optically readable information recorded on one surface thereof. Therefore, it is necessary to load the optical disc with the recording surface in a predetermined position. The loading position of the optical disk on the body of the playback device may not be directly visible from the outside, and in playback devices with such a configuration, it is difficult to see whether a disk is loaded or not.
There also arises a need to be able to know whether the disk is loaded in a position that allows playback.

In a typical prior art, a so-called transmission type optical detection means is provided to detect an optical disc 2 loaded in a body 1 of a playback apparatus as shown in FIG. That is, if the optical disk 2 is loaded, the light from the light source 4 of the optical detection means 3 is
The light is blocked by the optical disc 2 and is not received by the light receiving element 5, thereby indicating that the optical disc 2 is loaded. Detection of light from the light source 4 by the light receiving element 5 indicates that the optical disc 2 is not loaded. In such prior art, the light source 4 and the light receiving element 5 need to be placed on both sides of the optical disc 2 at the position where it is to be loaded, thus saving space for mounting the optical detection means 3. is large. Therefore, there is a problem that the playback device becomes larger. Further, with such prior art, it is not possible to know whether the surface of the optical disc 2 on which information is recorded faces the optical reading means 6.

Another prior art is configured to actually rotate and drive the optical disc 2 to perform a reproducing operation, and to determine whether information recorded on the optical disc can be read. Such a prior art does not require the optical detection means 3 in the prior art shown in FIG. 1, and has the advantage of having a compact configuration. The recorded contents of the disk 2 cannot be read unless it is rotationally driven, and there is a problem in that it takes a relatively long time to rotate the optical disk from a stopped state to a specified speed and read the recorded contents. . Further, in this prior art, a new problem arises when the configuration is such that the rotational speed of the motor that drives the optical disk increases until the recorded contents of the optical disk can be read. In other words, when the recording surface of the optical disk is not in a predetermined readable position and is turned upside down, or when the disk is not loaded, the rotational speed of the motor may be unnecessarily high. I get used to doing it.

Purpose The purpose of the present invention is to provide an optical disc playback device that can be miniaturized and that can reliably detect whether the optical disc is correctly loaded in a readable position at a predetermined loading position. It is.

Structure of the invention The present invention rotates the optical disc by a driving means with the optical disc loaded at a predetermined position in the main body of the playback device, and displays the recorded contents on one surface of the optical disc. In a reproducing apparatus for an optical disc read by a reading means, the light source is arranged on the same side of the optical disc as the reading means and emits light toward the position where the optical disc is to be loaded, and a light source that emits light toward the position where the optical disc is to be loaded; an optical detection means comprising a light-receiving element that receives light; and when an optical disk is to be detected by discriminating the output level in response to the output from the light-receiving element, (a) the light-receiving element receives reflected light; and (b) when the light-receiving element is receiving reflected light, the drive means is activated and the optical disk is rotated one or more times, and during that rotation, the light-receiving element stops receiving reflected light and the light is not received. The present invention is an optical disc reproducing apparatus characterized in that it includes a detecting means for detecting a change in the output of the element and detecting whether the optical disc is normally loaded.

Embodiment FIG. 2 is a diagram showing the configuration of an embodiment of the present invention. An optical disk 12 is loaded into the body 11 of the playback device using a so-called drawer or the like. Recording surface 12a on which information of this optical disc 12 is recorded
The contents are read by the optical reading means 13. The optical disk 12 is rotationally driven by a motor 14. The optical detection means 15
It is located on the same side (lower side in FIG. 2) as the optical reading means 13 with respect to the optical disc 12 loaded therein. This optical detection means 15 detects the optical disc 1.
A light emitting diode 16 as a light source that emits light toward the position where the optical disk 2 is to be loaded, and a phototransistor that receives the reflected light when the light from the light emitting diode 16 is reflected by the surface of the optical disk 12. A light receiving element 17 is provided.

A resistor 23 is connected in series to the phototransistor 17, and a connection point 24 thereof is connected to one input terminal 19 of the comparison circuit 18. The other input terminal 20 of the comparator circuit 18 is connected to resistors 21 and 2.
A voltage representing the discrimination level determined by 2 is provided. Comparison circuit 18 derives a high-level signal to output terminal 25 when the signal level at input terminal 19 is higher than the level at input terminal 20 . The output from the output terminal 25 is connected to the resistors 26 and 27.
The signal is inverted by an inverter 29 including a transistor 28, and is inputted from a line 30 to a processing circuit 31 realized by a microcomputer or the like. The output of the processing circuit 31 is sent to the drive circuit 32.
The motor 14 is driven and controlled by the output of the drive circuit 32. The output from processing circuit 31 is applied to the base of transistor 33. A light emitting diode 34 for display is connected in series to the transistor 33.

FIG. 3 is a diagram showing the label side 12b of the optical disc 12 on which no information is recorded. On the label surface 12b of the optical disc 12, a label on which information recorded on the recording surface, such as the number of songs to be performed, is written, is arranged in a semicircular arc shape or in a semicircular shape, as shown by reference numeral 35 in FIG. 3. It is pasted in a rectangular shape as shown by reference numeral 36 in FIG. With the optical disc 12 in the readable loading position as shown in FIG.
5 is located at the position indicated by reference numeral 15a in FIG. 31 and at the position indicated by reference numeral 15b in FIG. 32. Therefore, the optical disk 12 is the motor 1.
4, the optical detection means 15 detects the disk 12 as indicated by phantom lines 37, 38.
The position of the object will be detected.

Referring to FIG. 4, when attempting to perform playback, check whether or not the optical disc 12 is loaded in the aircraft body 11, and if the optical disc 12 is loaded, the recording surface 12a is 13, it is necessary to judge whether or not the direction is downward as shown in FIG. When the optical disc 12 is to be detected in this manner, the process moves from step n1 to step n2, and the processing circuit 31 determines whether the level of the line 30 is high. Recording surface 12a of optical disc 12
When the phototransistor 17 is directed downward in FIG. 2, the phototransistor 17 receives the light reflected by the recording surface 12a and becomes conductive. Therefore, the input terminal 19 of the comparison circuit 18 becomes high level, and a high level signal is derived from the output terminal 25. This causes inverter 29 to derive a low level signal on line 30. In step n2, the processing circuit 31
When detecting that the line 30 is at a low level, the processing circuit 31 causes the drive circuit 32 to drive the motor 14 in step n3. When the recording surface 12a of the optical disk 12 is facing downward in FIG. 2 as described above, the output of the optical detection means 15 does not change even if the optical disk 12 is driven one rotation or more, and therefore, step n4 From step n5
Then, it is determined that the optical disk 12 has been loaded normally. As a result, the processing circuit 31 gives a high-level signal to the base of the transistor 33, keeps the light-emitting diode 34 lit, indicating that it has been correctly loaded, and proceeds to step n4.
The operation ends at , and the reproduction operation of the optical disc 12 by the optical reading means 13 is continued.

When the label surface 12b of the optical disc 12 is facing downward in FIG.
5, 36 (see Figure 3) or when no optical disc is loaded.
Phototransistor 17 is cut off. Therefore, the output terminal 25 of the comparison circuit 18 is at a low level, and the line 30 is at a high level. The processing circuit 31 moves from step n2 to step n6,
It is determined that the optical disk 12 is not loaded normally, and as a result, the motor 14 is kept stopped, and a low level signal is applied to the base of the transistor 33 to turn off the light emitting diode 34, thereby indicating an abnormal state. Let me know.

It is assumed that the label surface 12b of the optical disc 12 is facing downward in FIG. 2, and the optical detection means 15 corresponds to the remaining area of the label surface 12b other than the labels 35 and 36 with high reflectance. do. At this time, the phototransistor 17 receives sufficient reflected light and becomes conductive. Therefore, the comparison circuit 18 derives a high level signal to the output terminal 25, and the line 30 becomes low level. The processing circuit 31 moves from step n2 to step n3,
The optical disk 12 is rotated by driving the motor 14 one or more revolutions by the drive circuit 32 . optical disk 1
2, the optical detection means 15 facing the label surface 12b traces the positions 37 and 38 (see FIG. 3) of the label surface 12b, thereby separating the regions of high reflectance from the region of high reflectance. Moving on to the small labels 35 and 36. Therefore, the output of the output terminal 25 of the comparison circuit 18 changes from low level to high level, and the line 30 changes from high level to low level accordingly. The processing circuit 31 detects that the output of this line 30 has changed in step n4, moves to step n6, determines that the optical disk 12 is not loaded normally, and turns off the light emitting diode 34.

Effects As described above, the present invention provides an optical detection means that emits light from a light source toward the recording surface or label surface of an optical disc and receives the emitted light from the optical disc using a light receiving element. Since the optical detection means is used, the structure can be miniaturized, and the space for installing the optical detection means can be small, so that the reproduction apparatus can be miniaturized. Furthermore, when the light receiving element does not receive reflected light, it derives a signal indicating an abnormality, thereby detecting that no optical disc is loaded.
It also indicates that the label side faces the optical reading means even if an optical disc is loaded.
Furthermore, even if an area with a high reflectance on the label surface is detected by an optical detection means, by rotating the optical disk one or more revolutions, an area with a low reflectance on the label surface can be detected. It can be seen that the label side of the optical disc faces the optical reading means side. In other words, according to the present invention, since the disk is rotated one or more revolutions and the front and back sides are determined by observing changes in the level of reflected light, the front surface of the recording disk has a substantially constant reflectance over the entire surface, while the back surface has a reflectance that is constant. Since the amount of light varies depending on the location, by rotating the disk and monitoring the level of received light, it is possible to determine whether the disk is front or back without false detection.

[Brief explanation of the drawing]

FIG. 1 is a simplified sectional view of the prior art, FIG. 2 is a diagram showing the configuration of an embodiment of the present invention, FIG. 3 is a diagram showing the label surface 12b of the optical disc 12, and FIG.
This figure is a flowchart for explaining the operation of the configuration shown in FIG. 2. 11... Airframe, 12... Optical disk, 12a...
... Recording surface, 12b ... Label surface, 13 ... Optical reading means, 14 ... Motor, 15 ... Optical detection means, 16 ... Light emitting diode, 17 ... Phototransistor, 18 ... Comparison circuit, 19 ... Inverter, 31 ... Processing circuit, 32 ... Drive circuit, 34 ... Light emitting diode for display.

Claims (1)

[Scope of Claim for Utility Model Registration] The optical disc is loaded in a predetermined position in the main body of the playback device, and the optical disc is rotated by a driving means, and the recorded content on one surface of the optical disc is transferred to one surface of the optical disc. A reproducing apparatus for an optical disc that is read by a reading means that faces the optical disc includes a light source that is disposed on the same side of the optical disc as the reading means and that emits light toward the position where the optical disc is to be loaded; an optical detection means comprising a light receiving element that receives reflected light; and when an optical disk is to be detected by discriminating the output level in response to the output from the light receiving element, (a) when the light receiving element receives the reflected light; and (b) when the light-receiving element is receiving reflected light, the driving means is activated and the optical disk is rotated one or more revolutions, and during that rotation, the light-receiving element no longer receives reflected light. 1. An optical disc reproducing apparatus comprising: a detection means for detecting a change in the output of a light receiving element and detecting whether an optical disc is normally loaded.