JP2637960B2 - Optical card recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to a card having an information recording medium capable of optically recording information (hereinafter referred to as an "optical card"). Recording (writing)
The present invention relates to an optical card recording / reproducing apparatus for reproducing (reading) recorded information, and in particular, the present invention relates to an optical card recording / reproducing apparatus having a two light source optical system of a light source for recording information and a light source for reproducing recorded information. It relates to a playback device.

<Prior Art> In recent years, as this kind of device, for example, as shown in FIG. 1, a first light projecting system using a laser diode 1 as a light source and a second light projecting system using a light emitting diode 2 as a light source are provided. Some have been proposed (details will be described later). As shown in FIG. 2, the first light projecting system generates a first light spot 5 for information recording on the information recording unit 4 of the optical card 3, and the second light projecting system generates the first light spot 5. The second light spot 6 for recording information reproduction is generated immediately after the position where the light spot 5 is generated. In FIG. 2, reference numeral 7 denotes a track guide for causing the optical system to follow when recording and reproducing information.

In this example of the apparatus, a hole-shaped information unit (referred to as a “pit”) 8 is recorded by a first light spot 5 by a first light spot 5 while sending the light guide 3 in a direction indicated by an arrow in the figure. Then, the second light spot 6 is generated on the pit 8. The reflected light of the second light spot 6 is guided to a light receiver 9 by a light receiving system, and an image thereof (hereinafter, referred to as an image).
A “detected image” is generated on the detection surface 10.

FIG. 7 shows a detected image of the second light spot 6.
The light receiving device 9 is located at the position of the image 12 of the pit 8.
Are located at corresponding positions. This photo detector
The presence or absence of the image 12 of the pit 8 and its length are detected by 13,
Thus, the recorded information is reproduced at the same time as the information is recorded on the optical card 3. 7, the dotted line 14 indicates the image position of the first light spot 5, and this image position 14 is immediately before the detected image 11 of the second light spot 6.

Normally, the laser diode 1 may not be able to record information properly due to aging or temperature change, or due to dust or the like adhering to the surface of the optical card 3. According to the device, since the recording information on the optical card 3 can be monitored immediately after recording, there is an advantage that the propriety of the recording information can be immediately confirmed.

<Problems to be Solved by the Invention> However, in the optical card recording / reproducing apparatus of the above-described method, the position of the photodetector 13 is changed to the detection surface 10 of the first light spot 5.
It is necessary to set the position immediately after the image position 14 above.
Since there is no standard for determining the relative positional relationship between the image position 14 of the light spot 5 and the set position of the photodetector 13, there is a problem that the position setting of the light receiver 9 is very difficult.
That is, in this type of two-light-source system, tracking control is performed so that the first light spot 5 is generated at the center of a predetermined track of the information recording unit 4, and as a result, pits and the like obtained by the second light spot 6 are obtained. Since tracking control based on the image of the track guide cannot be performed,
It is difficult to set the position of the photodetector 13 for reproducing recorded information to a position immediately after the image position 14 of the first light spot 5.

As a result, the photodetector 13 is displaced from the detected image 11 of the second light spot 6, and the photodetector 13 is slightly displaced from the position of the image 12 of the pit 8 as shown in FIG. Only by doing so, the S / N ratio of the detection signal decreases. The ninth
If the photodetector 13 is completely displaced from the position of the image 12 of the pit 8 as shown in the figure, it becomes impossible to confirm the suitability of the recorded information immediately after recording, and the advantage of this method is lost.

The present invention realizes a state in which a photodetector automatically corresponds to an image of a pit obtained by a second light spot when tracking control is performed based on the first light spot. By setting the position of the photodetector using the detected image of the first light spot, the position of the light receiving system is easily set, and the recorded information immediately after the recording is accurately and reliably reproduced. It is an object of the present invention to provide a new optical card recording / reproducing device which is enabled.

<Means for Solving the Problems> In order to achieve the above object, according to the present invention, a first light projecting system for generating a first light spot for information recording on an optical card, and recording on an optical card. A second light projecting system for generating a second light spot for information reproduction immediately after the first light spot, and a light receiving means for receiving reflected light of the second light spot from the optical card and A photodetector for reproducing recorded information for reproducing recorded information and a photodetector comprising a positioning photodetector for detecting reflected light of the first light spot from an optical card; A light receiving system provided with each photodetector in the light receiver so that the direction of connecting the devices and the feeding direction of the optical card imaged on the light receiver are provided, and the light receiving system is adjusted at the time of adjustment. The positioning photodetector is connected to the first light spot. The reflected light so as to properly received from the optical card, and configured to allow adjustment of the position of the receiver.

<Operation> When the first light projecting system is driven during the adjustment work prior to the operation of the apparatus, a first light spot is generated on the optical card. In this case, if the light output of the first light emitting system is lowered,
No pits are created on the optical card. The first
The reflected light of the light spot is guided to the light receiving system, and the light receiving device is positioned so that the image position thereof coincides with the position of the positioning light detector. As a result, the position of the photodetector for recording information reproduction provided in the same light receiver is automatically set.

After completion of this adjustment work, when the first and second light projecting systems are driven while the optical card is being fed, pits are formed on the optical card by the first light projecting system, and information is recorded. A second light spot is generated on the pit by the second light projecting system. The reflected light of the second light spot is guided to the light receiving system and forms a detection image on the detection surface of the light receiver. Since the light receiver is properly positioned with respect to this detection image, the other light detection The vessel will be positioned corresponding to the image of the pit,
There is no risk of lowering the S / N ratio of the detection signal, and the recorded information can be reproduced with high accuracy and reliability.

FIG. 1 shows an optical card recording / reproducing apparatus of a two light source system according to an embodiment of the present invention.

The illustrated device includes a first light projecting system for generating a first light spot 5 for information recording on the optical card 3 and a second light spot for reproducing recorded information on the same optical card 3. A light projecting system for generating the light beam from the optical card 3, and a photodetector for receiving the reflected light of the second light spot 6 from the optical card 3 and reproducing the recorded information of the optical card 3 immediately after recording; The first
A light receiving system having a light receiving device comprising a light detector for detecting the reflected light of the light spot from the optical card,
The light receiver is configured to be position adjustable.

The first light projecting system uses the laser diode 1 as a light source. The output light of the laser diode 1 is formed into parallel light by a collimating lens 15, and the parallel light passes through beam splitters 16 and 17. After that, the objective lens 18 focuses on the recording surface of the optical card 3 so that the diameter is about 1 mm.
A first light spot 5 of about μm is generated.

Since the laser beam has a high energy density, the laser beam is used for information recording.
When the light spot 5 is generated, a pit 8 having a shape as shown in FIG. 2 is recorded. The light reflectance of the pit 8 is lower than that of the other pits. When the second light spot 6 is generated on the pit 8, the amount of reflected light differs due to the presence of the pit 8. Thus, it is possible to determine the presence of a pit.

The second light projecting system uses the light emitting diode 2 as a light source. The output light of the light emitting diode 2 is formed into parallel light by a collimating lens 19, and the parallel light passes through the beam splitters 16 and 17. After that, the second optical spot 6 is generated by focusing on the optical card 3 by the objective lens 18.

Since the light emitting diode 2 has a large light source and the output light is not coherent light, the diameter of the second light spot 6 is larger than that of the first light spot 5 by the laser diode 1 as shown in FIG. Become.

Next, the light receiving system passes through the objective lens 18 and reflects the light reflected by the second light spot 6 out of the reflected light on the recording surface of the optical card 3 with the beam splitter 17 and then converges with the condenser lens 20. The presence / absence of the pit 8 and the data content thereof are determined based on the detection signal.

As shown in FIG. 3, the photodetector 9 forms a pair of photodetectors 13 and 21 formed of photodiodes on a single chip, for example, in a direction connecting the two detectors 13 and 21 and an image on the photodetector 9. In this configuration, the optical card is integrated at a predetermined distance so as to match the feeding method of the optical card. One of the photodetectors 13 is for recording information reproduction, and is located at a predetermined position of the detection image 11 of the second light spot 6. The other photodetector 21 is used for positioning the photodetector 13, and is set to be positioned with respect to the detection image 22 of the first light spot 5 during the adjustment operation.

FIG. 4 shows a second embodiment of the light receiver 9, in which a photodetector 21 for positioning is formed long in the card feeding direction.

FIG. 5 shows a third embodiment of the light receiver 9, in which the photodetector 21 for positioning is constituted by a pair of divided bodies 21a and 21b, and each of the divided bodies 21a and 21b is a second embodiment. Similarly to the above, it is formed long in the card feeding direction. Each divided body 21
As shown in FIG.
It is given as two inputs of four.

When the adjustment operation is performed prior to the operation of the apparatus, the laser diode 1 is driven after setting the light output of the laser diode 1 to a value large enough not to generate pits on the recording surface of the optical card 3. The output light of the laser diode 1 is converted into collimated light by a collimating lens 15 and then passes through beam splitters 16 and 17 to form an objective lens 1
8 converges on the recording surface of the optical card 3. As a result, a first light spot 5 is generated on the optical card 3. In this case, since the light output of the laser diode 1 has been reduced, no pits are generated on the optical card 3, and the light Are reflected from the optical card 3. The reflected light passes through the objective lens 18, is reflected by the beam splitter 17, is converged by the condenser lens 20, forms an image on the detection surface 10 of the light receiver 9, and forms the detected image 22 of the first light spot 5. Is generated.

Thus, while moving the light receiver 9, the light detector 21 for positioning in the light receiver 9 is positioned with respect to the detection image 22 so that the amount of received light is maximized. In this case, the direction in which the positioning photodetector 21 and the photodetector 13 for recording information reproduction provided integrally with the same light receiver 9 are connected, and the feeding direction of the optical card imaged in the light receiver 9 Match, the detected image 22
By positioning the positioning photodetector 21, the position of the recording information reproducing photodetector 13 is automatically set.

After the completion of the adjustment operation, when the laser diode 1 is driven at a predetermined output while the optical card 3 is being fed, a first light spot 5 having a higher energy density than that at the time of adjustment is generated on the optical card 3. The light spot 5 forms pits 8 on the recording surface of the optical card 3 with a thermal irreversible change to record information.

Further, by driving the light emitting diode 2, the output light is converted into parallel light by the collimating lens 19, passes through the beam splitters 16 and 17, and is converged on the optical card 3 by the objective lens 18. As a result, a second light spot 6 is generated on the optical card 3 immediately after the first light spot 5. The light reflected by the second light spot 6 passes through the objective lens 18 and is reflected by the beam splitter 17, and then is condensed on the light receiver 9 by the condenser lens 20, and is reflected on the photodetector 13 by the second light spot 6. A detection image 11 is formed.

This photodetector 13 is properly positioned with reference to the first light spot 5 at the time of adjustment, and is located at a position corresponding to the position of the image 23 of the pit 8.
When the photodetector 13 reaches the photodetector 13 with the card feed, the photodetector 13 detects the photodetector 13 with high accuracy and certainty and extracts it as reproduction information. FIG. 4 and FIG. In the third embodiment, the adjustment work is performed by driving the light emitting diode 2 in addition to the laser diode 1.
The detection images 22 and 11 of the first and second light spots 5 and 6 are formed on 10.

In the case of the second embodiment, first, the light receiver 9 is moved in the y direction in the figure to position the light detector 9 with respect to the detection image 22 of the first light spot 5 so that the amount of light received by the light detector 21 is maximized. Next, the light receiver 9 is moved in the x direction in the figure, and the detection image of the second light spot 6 is adjusted so that the amount of light received by the other light detector 13 is maximized.
Position with respect to 11.

In the case of the third embodiment, first, the photodetector 9 is moved in the y direction in the figure so that the differential output of the differential amplifier 24 becomes zero, so that the photodetector 21 is positioned on the boundary between the divided bodies 21a and 21b. After the first light spot 5 is positioned at the detection image 22, the light receiver 9 is then moved in the x direction in the figure, and the second light spot 6 is moved so that the amount of light received by the other light detector 13 is maximized. Is positioned with respect to the detection image 11.

According to each of the second and third embodiments, since the photodetector 21 for positioning is formed long in the card feeding direction, the interval between the detection images 11 and 22 may vary due to variations in the processing accuracy of parts. Even if it changes, there is an advantage that the positioning operation in the y direction becomes particularly easy.

In each of the above embodiments, the positioning photodetector 21 was used.
The circuit for extracting the detection signal may be provided in the apparatus, but may be connected to the outside as necessary at the time of adjustment work or the like.

In the above description, the description of the focusing mechanism and the tracking mechanism is not given. However, it is needless to say that these embodiments are provided with these mechanisms.

<Effect of the Invention> As described above, according to the present invention, the photodetector of the light receiving system is provided with the photodetector for detecting the reflected light of the first light spot for information recording. The position of the light receiver can be set as a reference, the setting error is reduced, and the S / N ratio of the detection signal can be improved. In addition, since the reference for position setting is obtained, the position adjustment work is remarkably easy, not only can the adjustment process be greatly reduced, but also it is not necessary to increase the mounting accuracy and processing accuracy of each component in the light receiving system more than necessary. , Contributing to reduction of parts processing cost,
A remarkable effect of achieving the object of the invention is achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an optical system of an optical card recording / reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a configuration of an optical card and a positional relationship between first and second light spots. ,
FIG. 3 is an explanatory view showing the structure of the light receiving device, and FIGS.
FIG. 6 is an explanatory diagram showing the configuration of another embodiment of the photodetector, FIG. 6 is an electric circuit diagram showing a detection signal processing circuit for the embodiment of FIG. 5, FIG. 8 and 9 are explanatory diagrams of the principle for explaining the problems of the conventional system. 1 laser diode 2 light-emitting diode 9 photodetector 13,21 photodetector

Claims (3)

(57) [Claims] 1. An optical card recording / reproducing apparatus for optically recording and reproducing information while relatively moving an optical card with respect to a light projecting system, wherein a first light spot for information recording is generated on the optical card. A first light emitting system for generating a second light spot for recording information reproduction on the optical card at a position immediately after the first light spot, and a second light emitting system. A photodetector for recording information reproduction for receiving the reflected light of the spot from the optical card and reproducing the recorded information of the optical card, and a positioning device for detecting the reflected light of the first light spot from the optical card. A light receiving system having a photodetector comprising a photodetector, wherein the photodetector is provided with each photodetector such that a direction connecting the two photodetectors coincides with a feed direction of the optical card imaged on the photodetector; The light receiving system is used for positioning when adjusting. An optical card recording / reproducing apparatus configured to be capable of adjusting the position of the photodetector so that the photodetector appropriately receives the reflected light of the first light spot from the optical card. 2. The optical card recording / reproducing apparatus according to claim 1, wherein said first light projecting system uses a laser diode as a light source, and said second light projecting system uses a light emitting diode as a light source. 3. The optical card recording / reproducing apparatus according to claim 1, wherein said positioning photodetector is a photodiode.