Compatible optical scanning device

 

(57) Abstract:

Usage: in the technique of optical recording of information, in particular, for scanning the first and second types of optical recording media. The inventive device, the radiation source produces a beam of radiation of the first wavelength. Formed by this beam radiation in the form of a scanning or reading spot is on the Central line intended for reading the tracks on the recording media of the first type designed for this wavelength. In case of reading the second type of recording medium, the read spot in accordance with the invention will be exactly take the edge intended to read the track and not on the Central line. Thanks satisfactory information signal is formed by scanning of the recording media of both the first and second types. 9 C.p. f-crystals, 11 ill.

The present invention relates to a device intended for scanning the first and second types of optical recording media in the first and second modes, respectively, with each type of recording medium has an information plane patterns formed on the tracks and containing Informationen with the possibility of scanning the radiation of the first wavelength, and the second type is made with the possibility of scanning the radiation of the second wavelength, the first wavelength is shorter than the second wavelength, the said device comprises a radiation source for education and supply a beam of radiation of the first wavelength, a lens system for focusing the beam of radiation with the formation of the scanning spot on the information plane, the first detection system for converting radiation of the scanning spot on the information plane of the information signal and the tracking system, the mode of operation of which is governed by the error signal tracking for permanent retention scanning spot on the Central line of the track to be scanned in the first mode.

The need to create this type of device due to the fact of development and further development of new radiation sources that generate radiation at a shorter wavelength than was customary up to now, for example, laser diodes with short wavelength radiation sources, created on the basis of the optimum combination of properties of conventional diode lasers and frequency doubler. If such a new radiation source used in the device scitis the ability to read new media with smaller information and details with a higher density of information, than usual. Currently already use large quantities of normal of the recording media or information and it is highly desirable to have a suitable to read these media recording a new reader.

Described in the first paragraph of the device known from the description of the patent application of Japan N 2-83830. This device can read the recording media with different density of information in the corresponding adapting the size of the read spot on the information plane in relation to the density of information, i.e. the read spot will increase for reading the recording media with a large amount of information detail. It was found that the phase structure in the information plane, intended for reading on a long wavelength, it is not always easy to read beam having a short wavelength. In the known device the spot increases in the corresponding movement plane-parallel plate in a convergent beam of radiation. As a result, the focus of the beam will be displaced along the optical axis and to increase the cross-section of the beam in the field of information plane.

The disadvantage of this method is that is, the installation in this period of additional plates will be associated with greater risk that the recording medium will directly touch the plate and may be damaged as a result of shock about the device.

Another disadvantage is that if you change the type of the recording medium a component, in this case, the plate will be displaced, which is highly undesirable and dangerous in a situation where there is no sufficient free space.

The main purpose of the present invention is to provide a device, which would be free from the above disadvantages.

Therefore, the device according to the present invention differs in that the tracking system is designed in such a way that she always kept reading spot on the edge of the track to be read for the second reading mode. It is possible that the recording media of the second type can be easily and conveniently read in if instead of increasing the read spot to make it's reading spot just to follow the edge of the track. Necessary in this case, the lateral displacement of the spot can be easily implemented without liberalizovanog any reader of the recording media of the second type, characterized by identical period tracks, but different width tracks. It was found that the device according to the invention will function properly in the case, if in the second mode, the tracking system will keep the center of the read spot at some distance from the Central line of the track, which will be read and referred to the distance will be equal to one fifth of the period of the track of the second type of recording media.

According to the first exemplary embodiment of the invention the device is characterized in that the error signal tracking is fed to the first input of the electric circuit of the tracking system, the second input of which is connected to the switch for adding a DC signal (DS) in the error signal tracking in the second mode. Mentioned electric circuit provides electrical offset of the tracking system, so that the read spot is not followed by the Central line, and followed the edge of the track.

Feature of the device according to the first exemplary embodiment of the invention is that this device contains circuitry to determine the quality of the information signal and for supplying the DC signal (DC), which depends on referred to cacheserver position of the read spot in the second mode.

The device according to the second exemplary embodiment of the invention differs in that it contains means for generating a tracking beam, which, in turn, forms a witness mark using a lens system, and this witness spot is located transversely relative to the scanning spot and the detection system monitoring for receiving radiation tracking beam from the information plane, the device further comprises a switch with two inputs and one output, which is connected with the control input of the tracking system, and the first input of the switch, which is connected to the output of the switch in the first mode, connected to the output of the system generation and signal tracking error based on the output signals of the first detection system, and the second input of the switch, which is connected to the output of the switch in the second mode, is connected to the output of the additional scheme of forming the error signal tracking based on the output signals of the first detection system and the detection system monitoring. In the second mode to generate the error signal tracking using the optional beam. Since the proposed device is not used for the above DOPOLNITEL record.

The third mode can be used in the device characterized in that it comprises means for generating two tracking beams through lens system will form two tracking spots, and witness these spots will move transversely and located at two sides of the scanning spot, and two detection systems tracking for receiving radiation of the two tracking beams from the information plane, while the above device further comprises a switch with two inputs and one output, which is connected to the input of the servo control system, and the first input of the switch, which is connected to the output of the switch in the first mode, connected to the output of the circuit for the formation of the error signal tracking based on output signals of at least two detection systems tracking, and the second input of the switch, which is connected to the output of the switch in the second mode, is connected to the output of the additional schemes for the formation of the error signal tracking based on the output signals of the first detection system and one of the detection systems tracking. To effect the displacement of the spot is quite simple electric switch system LCD of the first and second types of recording media.

A preferred exemplary embodiment of the device according to the invention is characterized by the fact that in the second mode, one of the tracking spots exactly follows the edge of the track. As a reading spot, and one of the tracking spots exactly follows the edge of the track in the second mode, in this case to simply and easily create an error signal tracking in the form of a signal difference between the first detection system and the detection system monitoring associated with the next patch.

Device according to another exemplary embodiment of the invention uses the third offset mode, in accordance with which the second wavelength is two times bigger than the first wavelength; a device according to this exemplary embodiment of the invention differs in that the transverse distance between the two tracking spots is essentially 1.5 times the period of the track of the first type of recording media. This example implementation of the device is acceptable, among other things, to players, in which the radiation of the first wavelength generated by doubling the frequency of the radiation of the second wavelength.

If the device according to the present invention differs in that at least one of the detection systems contains two detector, claridon track and the width of the track.

Another preferred example of the device according to the invention differs in that it contains a discriminator type, the output of which is connected to the tracking system, which is driven so that the device is in a mode that is directly associated with a type intended for reading the recording media. Now this device will be automatically installed in the correct mode of reading the recording media.

Below the invention is described in more detail and with reference to the accompanying description of the drawings in which are shown: Fig. 1 the optical head of the reading device; Fig. 2a bottom view of the phase patterns of the first type of recording medium together with the reading spot adapted to this phase structure; Fig. 2b is a cross section of the phase structure and the readout spot, taken along the line a-a of Fig. 2a; Fig. 2c tangent section of the phase structure and the read spot Fig. 2a; Fig. 2d used in this case, the information signal; Fig. 3a bottom view of the phase patterns of the second type of recording medium together with the reading spot, which will be too small and which is not adapted mentioned phase structure. Fig. 3b is a cross section of the phase structure and Leshey in this case, the information signal; Fig. 4a bottom view of the phase patterns of the second type of recording medium together with the reading spot which the present invention is shifted in the transverse direction; Fig. 4b is a cross section of the phase structure and the read spot Fig. 4A. Fig. 4c is a tangential cross-section of the phase structure and the read spot Fig. 4a; Fig. 4d is used in this case, the information signal; Fig. 5 the optical head along with the tracking system to perform the tracking function with the first mode; Fig. 6 optical head for tracking in accordance with the second mode; Fig. 7a and 7b, the positions of the spots in accordance with the second mode tracking on the phase structure of the recording media of the first and second types; Fig. 8 optical head tracking in a third mode; Fig. 9a and 9b, the position of the spots in accordance with the third mode of the tracking by the phase structure of the recording media of the first and second types; Fig. 10 optical head tracking on the fourth mode; Fig. 11a and 11b, the positions of tracks on the fourth tracking mode on the phase structure of the recording media of the first and second types.

The same reference position in the different drawings to designate the same components of the device.

In Fig. 1 shows a cross section of pricheskoj head of the reader. A recording medium provided with an information plane 2, which stores information in the form of phase patterns. This phase structure may be in the form of pits (pit) (pits) or columns (bumps), located on the information plane. Phase structure is located on tracks 3, which, in turn, are perpendicular to the plane of the drawing. The optical head contains the radiation source 4, for example, a diode laser. Emerging from the mentioned source of a beam of radiation 5 focuses on the read spot 7 in the information plane 2 through the lens system 6. Not shown in Fig. 1 the witness keep reading spot in the information plane and on the track 8 to be scanned. Beam radiation 9 reflected from the information plane, modeled information of the phase structure. The beam splitter 10, for example, a partially transparent mirror, transmits reflected radiation-sensitive radiation detection system 11, which converts the modulated beam into an electrical signal information 12.

The size of the read spot 7 and the geometry of the phase structure must be consistent with each other to ensure a good education modulation reflects the respect to the read spot 7 and which is read in reflection. In Fig. 2a and 2b shows a bottom view and cross-section information plane 2; here shows three adjacent, track 3, the center line of which is indicated by the dotted lines 13. The Central track 8 is the track that will be read. The distance between the centerlines of adjacent tracks, i.e., the period of paths, denoted by the reference position p1. In the recording medium 1 in this example, the phase structure is represented by a number of recesses (pits), centered on the Central line, on which the information encoded along the length of the grooves and the spacing between them. The width of the holes or the width of the track denoted by reference POS. W1. In Fig. 2b shows a cross section of the recording media, taken along the line A-A. the Beam of radiation 5 is focused at a location deeper (Pete) 14 in the information plane 2. In the information plane 2 beam radiation forms the read spot 7, the size of which is proportional to the wavelength of the radiation. The intensity of the reading spot is the maximum usually in the center of the spot and will decrease towards the edge. Information plane 2 reflects the radiation of the read spot 7, the diameter of the spot is bigger than the width of the path (due to a certain depth of the recesses (Pete), what part of the beam reflected outside the recess. Therefore, between the two reflected portions of the beam produces a phase difference, so that this beam will be modulated in phase. The depth of the recesses (Pete) determines the phase difference between the said parts of the beam; the ratio of the surface area of the read spot 7 inside and outside of the recess 14 defines the mutual intensity of the two parts of the beam. Depending on the phase difference of these pieces rays interfere constructively or destructively in the detection system 11. If the depth of the recess forms a phase difference of 180oand if an equal portion of the radiation reflected from inside and outside the cavities, then in principle it is possible to achieve 100% modulation of the information signal. In Fig. 2c, the recess 14 is shown in cross section, and Fig. 2d shows used in this case, the information signal 12, shown here in reference POS. S as a function of the position of the read spot 7 with respect to the recess. The maximum modulation of the information signal is achieved when the read spot is located entirely above the recess.

The above-described device, equipped with a radiation source 4, which forms and outputs the first radiation whose geometry phase structure adapted to the first wavelength. The period of paths p1 and path width W1 will be relatively small, for example, 0.8 μm and 0.3 μm, respectively. Read this new type of recording media is made possible through the use of a conventional diode laser with a wavelength of 0.8 μm in combination with a frequency doubler, which converts radiation of the diode laser radiation of a half wavelength. It is desirable to use the device it was possible to read the recording media of the second type, the design of which is intended to read them at a greater wavelength than the first wavelength.

In Fig. 3a shows a bottom view of the recording medium 15 of the second type, for example, recording audio, which is better known under the title of "CD" or "CD". This recording medium is optimized with a view to its subsequent reading using a second beam whose wavelength is equal to the wavelength of radiation from a conventional diode laser, the radiation of which is doubled in frequency. If using the same lens system 6 of the second beam forms a second reading spot, which is 2 times higher compared to the one shown in Fig. 2b of the read spot 7. To frequent the may from the environment referred to deepen at the moment of reading with second reading spots the width W2 of the recess 16 should be 2 times greater than the width W1 of the recess 14 of the recording medium 1. To be able to count the tracks of the recording medium 15 through the second reading spot with minimal crosstalk, it is necessary that the period of paths p2 of the recording medium was about 2 times longer than the period of the track of the recording medium 1. Moreover, the depth of the recesses 16 must be 2 times the depth of the recess 14, for only in this case it is possible to achieve a phase difference of 180obetween the parts of the beam in the second reading spot of the second wavelength. If the second recording medium are read using a beam 5 of the first wavelength, then a problem arises in that it is formed by this beam of the read spot 7 will not match the geometry of the recesses 16. If the center of the read spot 7 is located on the center line 18 of the track, as shown in Fig. 3a case and in the cross section of Fig. 3b, then, in that moment, the part reflected from the deepening of the beam will be much more intense compared to the part of the beam reflected from the area outside the recess. Moreover, because of the slightly greater depth of the recess 16, the phase difference between the two parts of the beam will be equal to priblisitelno interference and that the information signal 12 has a smaller modulation depth.

At the time of scanning deepening (Pete) 16 of the read spot 7 will be located above the front edge of the recess in a short period of time, as shown in Fig. 3c. This situation differs from the above-described case, when the beam was directly above the recess. Radiation reflected from the middle of the slope of the leading edge will be shifted in phase by approximately 180oin relation to the parts of the beam which is reflected from three sides outside the recess and the bottom recess. If the center 19 of the read spot (when functioning at maximum intensity) is located in the middle of the slope, in this case, the intensity of the beam reflected at the middle of the slope, can be comparable with the intensity of parts of the beam reflected from the bottom side and the outer side of the recess. This causes destructive interference, which ultimately leads to quite strong modulation of the information signal 12 at the starting point location. In Fig. 3d shows an example of the information signal, indicated here by the reference position Si, as a function of the position of the center of the read spot 7 with respect to the recess 16. In this case, the celebrated bas is in the recess will be weak due to the above-described small destructive interference. This distortion of the information signal relative to the signal shown in Fig. 3d, may create some difficulties in processing the information signal. The device detects the presence of deepening by detecting the moment when the information signal will be below a specific level. In Fig. 3d this level is shown by a dotted line. Due to the distortion of the information signal in this case instead of one of the recesses will be formed of two, and therefore will be detected two hollows. The end result of this is that you will generally be considered or may be considered only with great difficulty and inaccurately second type of recording media.

The present invention offers an effective solution to this problem, and problem tracking at the moment of reading the second type of recording media of the first wavelength; in addition, the invention provides a new device that will work on wave length (minimum from the above-mentioned wavelengths), where you will not only be satisfactorily read track two types of the recording media, but also to positively solve the problem of tracking. The proposed device will work with two p is described with reference to Fig. 2a, 2b, 2c and 2d. At the time of reading of the second type of recording medium using the second readout mode, in accordance with which the center of the read spot 7 is shifted in the transverse direction, i.e. perpendicular to the tracks 3 toward the edge of the track. In Fig. 4a and 4b show the read spot 7, which has already been shifted by a distance S from the center line 18 of the track. Because the center 19 of the read spot 7, i.e., having the maximum intensity part, is now located above the inclined wall 20 of the recess, the effect of inclination on the reflected beam will be greater than shown in Fig. 3a situation. The phase of the reflected radiation varies from 0ofor part of the beam reflected in the zone 21 outside the depressions 180ofor the radiation reflected at the center of the inclined wall 20, and up to about 360ofor radiation reflected from the bottom part 22 of the same recess. Part of the beam reflected from zone 21 and bottom 22, will be destructive to interfere with a part of the beam reflected from the mid-point of the inclined wall 20. The intensity of the beam reflected from the mid-point of the inclined wall of the recess depends on the degree of inclination of this wall. The results of the experiments indicate that talona gives the best results. This range is also the area within which it is possible to obtain the optimum recording media using a molding process. Due to the high intensity of the beam 5 in the center 19 of the two parts of the beam will be comparable in intensity in the case of angle in the above-mentioned limits and will ensure acceptable modulation of the reflected beam 9. In turn, this will ensure satisfactory modulation of the output signal of the detection system 11, and, consequently, satisfactory reading the information signal from the recording medium 15. In the form shown in Fig. 3a situations when the read spot 7 feels no offset will also undergo destructive interference between the part of the beam reflected from the center of the inclined walls 20, and a part of the beam reflected from the area around the cavities and from the bottom 22 of the recess. Nevertheless, because of the higher intensity beam 5 falls on a point at the bottom 22 of the recess, the intensity of the other parts of the beam are very different among themselves. Hence, in Fig. 3a shows less destructive interference, in which the reading of the recording medium 15 is fiveusa spot 7 is positioned above the front edge of the recess 16 (Fig. 4c), then there is the same strong modulation of the information signal, as shown in Fig. 3c. However, since at the moment the modulation of the Central recess will be much stronger than in the situation of Fig. 3c, the information signal will not fall below the level of the read spot reaches the middle point of the edge of the recess. It is shown in Fig. 4d information signal Siis for reading according to the present invention, the same periodic changes, as shown in Fig. 2d information signal at the time of normal reading is known by the reader, therefore, the information signal Siyou can properly and effectively handle. The depth of modulation of the information signal depends on an inclination of 20, the diameter of the read spot 7 and the displacement "S", and usually it will be slightly less than when reading data with the read spot, which is designed to be used in this case, the recording media. However, this situation can be corrected through the use of additional amplification.

The offset value "S" to achieve satisfactory information signal is not critical. It was established, the output results can be achieved in the case if you have to read the recording media, which are characterized by a relatively large variation in any specific dimensions. For example, in CDs, there was a slight variation in the period of paths p2, but a fairly large variation in track width W2. It was found that for displacement "S" in the range between 0.1 and 0.3, and preferably 0.2 times the period of the paths p2, there are opportunities for satisfactory read the majority of the currently used media accounts, and this ability will not depend on the width of the track and the diameter of the read spot.

Therefore, we offer the reader makes unnecessary the process of adapting the bias applied to the recording media of the second type and may use a fixed offset in the second mode. Although the present invention is described with reference to EcoObraz phase structure (with grooves), however, it is clear that the basic principle of the invention will be effective for all other phase structures, including for stabilometric structures. The ratio between the first and second wavelengths is not necessarily equal to a factor of 2, and in equal steeets constant.

Pets are a few examples of execution of the device according to the invention, moreover, in all the examples of execution of the device in the process of implementing the second mode of the read spot 7 will be displaced in the transverse direction. The first example implementation of the device shown in Fig. 5. The error signal tracking 23, reflecting the deviation between the center of the read spot 7 and the Central line 13 tracks 8 to be scanned is obtained from the detection system 11. The said signal is fed into the tracking system 24, which forms the input signal for the driver 25 to the next, for example, the transverse displacement of the objective lens 6. Lateral displacement of the lens 6 has the end result of lateral displacement of the read spot 7. The error signal tracking 23 can be formed in several ways. In U.S. patent N 4491940 described method, whereby the detection system may include two parts, and when the difference between the output signals of these two parts serves as a criterion for error tracking. In U.S. patent N 3376842 described another method of forming the error signal tracking, which is two tracking spots are formed on both sides of the read spot. Two beams of radiation from the witness of the five who Riem error tracking.

The offset of the read spot, is required for the second mode can be achieved by feeding the control signal 26 from the constant current source 30 in the tracking system 24. The specified constant current source is connected through the switch 27 to the input of the electrical circuit 28, for example, to the input of summing amplifier tracking system 24. If the device needs to read the recording medium 1 of the first type in the first mode, then the switch 27 supplies a zero voltage in the circuit 28. If the device needs to read the recording medium 15 of the second type in the second mode, then the switch 27 sends a control signal 26 in the summing amplifier 28. In summing amplifier 28 are combined error signal tracking 23 and the control signal 26 so that the output signal was represented by the offset DC current error signal tracking. This signal will adjust the operation mode of the driver 25 through additional servo system 29, for example, via the amplifier. Due to the DC offset of the read spot is no longer to follow the centre line 13 of the track 8. The position of the switch 27 will determine the status of the device, i.e. whether it is in the first or second mode is, which is determined by the quality of the information signal 12, and this definition is based on verification, for example, voltage levels of the information signal or the measurement result of the frequency error after analog-to-digital conversion or the correction value of the control signal 26 with the mentioned data and thus to the quality of the information signal in the second mode as possible. Because the circuit 30 will determine the maximum value quality, then you may need in making a reading spot small lateral swing. After that, on the basis of the net change in the quality of the information signal can be simply and easily determine the maximum value.

In Fig. 6 shows a second exemplary embodiment of the device according to the invention for shifting the read spot 7 in the transverse direction. In this drawing, the tracking beam 32 derived from the beam of radiation 5 using a diffraction grating 31. For the maximum possible concentration of radiation in the beam of radiation or the reading beam 5 and diregiovani tracking beam 32 may require special processing of the diffraction grating 31. Witness Lunia 34, which detects radiation from the witness spots 33, will be located near the detection system 11. The position of the spots 7 and 33 on the first type of recording medium shown in Fig. 7a. The centre of the read spot 7 accurately follows the centre line 13 of the track 8, which should be read. Center servo spot 33 is shifted by the distance d relative to the same center line 13. According to this exemplary embodiment of the invention witness the stain is not used in the case when the read recording medium of the first type. As the information signal and the error signal tracking are displayed on the basis of the read spot 7 in its first mode. This purpose is shown in Fig. 6, the detection system 11 is divided into two halves 11a and 11b. Summing amplifier 35 produces the sum of the output signals of these two halves; the output signal of the summing amplifier is an information signal 12. Differential amplifier 36 produces and outputs push-pull (push-pull) signal detection system 11, i.e., the signal difference between two halves. This signal is the error signal of the tracking 23 and he is fed through a set in the first position of the switch 37 in the circuit 29 to perform tracking functions.

In Fig. 7b shows the STD of the read spot 7 is shifted by the distance S from the center line of the track 38, which should be read, and now just follows the edge of the track 38. The transverse distance d between the centers of the read spot and the tracking spot is selected so that the witness spot 33 just followed the other edge of the track 38 in the second mode. And in this case, the signal amount detection system 11 will be an information signal 12. Now the difference between the information signal 12 and the signal detector 39, the detection system 34 is used as the error signal tracking. Since the intensity of the beam of radiation in General will be more intense tracking beam 32, therefore, the signals of the detection system 11 and 34 need to be adapted before they subtract from each other. It is shown in Fig. 6 using the attenuator 40, which provides the attenuation information signal 12 by a factor equal to the ratio of intensity between the beams 5 and 32. Differential amplifier 41 generates a signal difference between the output signal of the attenuator 40 and the signal 39. After that, the difference signals are fed into the control signal through the set in the second position of the switch 37 in serwotka 29 to perform tracking functions.

The necessary shift or offset S ODA the spots is equal to 2S and does not depend on the period of paths p2. Therefore, the device according to the second exemplary embodiment of the invention can read the recording media of the second type with different or varying periods of tracks. It is obvious that shown in Fig. 7b witness the spot, may move through an integer number of tracks. In the second mode, the tracking spot 33 may alternately be located exactly between the two tracks. The error signal tracking now becomes a push-pull signal detection system 34, is divided into two halves, the signal which can be formed exactly the same as push-pull signal detection system 11. In order to obtain a satisfactory push-pull signal, the size of the tracking spot must be large enough in relation to the period of paths p2.

In the device according to the third exemplary embodiment of the invention uses the first mode of the method of forming the error signal tracking using the tracking spots; this method is already known, for example, from U.S. patent N 3876842, which provides a description of the method used in the first mode. This example is shown in Fig. 8. The beam of radiation from the source 4 is divided into a reading beam 5 and two servo beam 43, and the division of radiation occurs with the n here by dashed lines. These tracking beams form two tracking spots 44 and 45 on both sides of the read spot 7. The detection system 11 detects radiation from the read spot 7, and two detection systems tracking 46 and 47 detect the radiation from the witness spots 44 and 45. In Fig. 9a shows the position of the read spot and the tracking of spots they occupy on the information plane 2 of the first type of recording medium 1 during the implementation of the first mode. The centre of the read spot 7 accurately follows the Central line 13, which is designed to read the track 8. The centers of the two tracking spots are located at a distance d1 from the center line on both sides of the read spot. In the process of implementation of the first mode, the output signal of the detection system 11 is represented by an information signal 12, and the error signal for tracking is formed on the basis of the signals of the detection system 46 and 47. To this end the output signal of the detection system 47 is fed through a set in the first position of the switch 48 and a differential amplifier 49. The output signal of the detection system 46 is fed to the other input of the differential amplifier. The output signal of the differential amplifier 49 is the desired error signal tracking 23. In the spot exactly followed the edge of the track, which should be read on the second type of recording medium, as shown in Fig. 9b. Witness the spot exactly 44 follows the edge of the track. And in this case, the information signal 12 is represented by the output signal of the detection system 11. According to the invention, the error signal tracking is now formed on the basis of the output signals of the detection system 11 and 46. As shown in Fig. 6 device, the output signal of the detection system 11 should fade with attenuator 50, and only after that he served in the differential amplifier 49 through the switch 48, which at this moment is in its second position. The output signal of the differential amplifier 49 is the error signal of the tracking 23.

If the distance d1 is equal to 3/4 of the period of paths p1, then in the first mode, obtains the optimal error signal tracking 23. The mutual distance between the witness spots 44 and 45 will now be 1.5 times the period of the paths p1. To obtain satisfactory information signal 12 in the second mode, it is necessary that the displacement S, which is equal 1/2 d1using the tracking system was between 0.2 W2 and 0.9 W2, and in this case will be the width of the tracks 3 of the second type of recording media, in kotohime. If p2 is not equal 2p1, as well as, for example, 1.5 p1, in this case, the center of the servo spot 45 on the second type of recording medium will accurately follow the track, which will be near the track, which will be read. For the formation of the error signal tracking instead of using the difference between the signals of the detector spots 7 and 44, you can use the difference between the signals of the detector spots 7 and 45.

The fourth exemplary embodiment of the device is a modification of the third example, which was described above. According to the fourth exemplary embodiment (Fig. 10) of the read spot 7 and two tracking spots 44 and 45 are formed in the device exactly the same as in the case of the example shown in Fig. 8. In Fig. 11a shows the position of the read spot and the tracking of spots on the information plane 2 of the first type of recording medium 1 in the first mode. The centre of the read spot 7 accurately follows the Central line 13, which is designed to read the track 8. Two tracking spots are located at a distance d2 from the center line on both sides of the read spot. In the first mode, the error signal of the tracking output signal-based detection systems 46 and 47. Each of the three detection systems 11, 46 and 47 consists of two polovinki and difference signals in the circuit 51 using the signals S1 and D1, respectively (Fig.10). Circuit 51 may include summing and differential amplifiers 35 and 36 (Fig. 6). The signal of the sum S1 of the circuit 51 is an information signal 12. Scheme 53, which is comparable to the circuit 51 generates a signal of the sum and difference signals S2 and D2 from the halves of the detection system 46. Differential amplifier 53 forms a difference signal D3 from the halves of the detection system 47. The error signal tracking can be formed only by the signal D2 or D3, or the sum of the signals D2 and D3. If there is a signal D1, then using a combination of the signals D1, D2 and D3 can be used to form a stable signal of the tracking error, what is already known from a European patent application N 0201603.

In this case, the signal D1 is multiplied by a constant in the circuit 54 and then subtracted from the sum of the signals D2 and D3 in the amplifier 55. The output signal of the amplifier 55 is a signal of the tracking error, which is fed through a switch 56 to its first position in serwotka for tracking. In the second mode, the center of the read spot is shifted by the distance S equal to d2, with respect to the center line 18 to the center of the read spot exactly followed the edge of the track, which will be read on the second type of recording medium, as shown in Fig. 11 b. Then center the witness patney detection 46 can be used as an error signal tracking. If shown in Fig. 11b witness spot 45 is moved approximately to the right between the two tracks and quite large in relation to the period of paths p2, in this case a stable signal of the tracking error can be obtained as a result of formation of the difference signal on the basis of the signals D2 and D3, and with the help of the differential amplifier 57. The output signal of the differential amplifier 57 can be submitted to serwotka through the switch 56 when it is being in the second position.

Satisfactory error signal tracking in the first mode can be obtained according to the fourth exemplary embodiment, when d2 is equal to the half period of the paths p1 of the first type of recording media. If the period of paths p2 of the second type of recording medium is 2 times more period of paths p1, in this case, the center of the servo spot 45 on the second type of recording medium will be exactly between the two tracks, and, therefore, is to provide education satisfactory error signal tracking in the second mode. The presence of grooves between tracks contributes to further improving the signal quality error tracking. If p2 is 1.5 p1, then the read spot 7 can be displaced in the second mode at 1/Ki, which will be read. In this case, the error signal of the tracking will be the difference between the sum signals S2 and S1.

Description four examples of carrying out the invention clearly indicates that there is a possibility to create such an optical head that can read two types of the recording media, for any combination of periods of paths p1, p2 and track width W1, W2 of the first and second types of recording media. The error signal tracking in General can be obtained by any of the methods described above or by some combination of these methods. The mentioned tolerance in the relationship between the displacement S of the read spot and the track width W2 is very important in the sense that there is no need for the exact adherence to the centre of the read spot at the edge of the track in the second mode, and at the same time there is the opportunity to achieve satisfactory information signal. This gives the user more freedom in terms of placing stains on and between tracks. Although the principle of operation two modes of the device described with reference to two types of recording media, both of which have the phase structure, but for the second type of recording media, the only prerequisite is nalbant, for example, in amplitude structures, for example, in areas with different reflection, or magnetic domains. Both types of the recording media can have grooves for the respective directions of the read spot.

If the proposed unit is functioning correctly, then you will switch 27, 37, 48, or 56 to select the mode, which is directly connected with the type of recording media to be considered. For this purpose, the device can be provided with a discriminator type 58, and which can determine the type of recording medium to be read, and with reference to which you can install the switch in the correct position. This discriminator can be used with all devices that have been described above and one of which is shown in Fig. 10 as an example. The first stage of determining the type of recording media is that the discriminator reads the label type on the recording medium on the basis of this tag specifies the type of the recording media. Then the discriminator type can set the switch in position for the first mode, if the label is there, and in the second mode, if no such tag. The corresponding label can be detected indywidualnych, if the device operates in the second mode, i.e. with the reading spot on the edge of the track. This can be done with labels containing the phase structure of the second type or some type of bar code, when the strokes are perpendicular to the direction of the track, so you can read the code without the need to accurately follow the tracks on the recording medium. There is a second possibility to determine the type, according to which there is no need to supply the recording media of some mark, and the discriminator must simply determine the quality of the information signal according to the method, which is similar to trigger circuit 30. If the mode in which the device starts to read the recording medium, generates too many errors in the information signal, then the discriminator may decide to switch to a different mode of reading. There is the opportunity to test two modes at the initial stage of reading the recording media, and then choose the one that gives information signal of the highest quality.

Although the above was described only function reading device according to the invention, however, it is possible to carry out using the same device on which they perform the function of recording spots, which will exactly follow the track, which is expected to make a record, and which will be of greater intensity than the read spot.

1. Device for reproducing information from the optical media recording the first and second types in the first and second modes, respectively, with the recording media each type has information plane formed by the structure of the organized tracks having respective axial lines and edges and containing the information, and the specified structure on the recording medium of the second type is the phase structure, the specified recording medium of the first type is designed to scan the radiation with the first wavelength and the recording media of the second type is designed to scan radiation with a second wavelength greater than the first wavelength, containing a radiation source for supplying radiation beam with the first wavelength, a lens system for focusing the radiation beam to a scanning spot on the information plane, at least one detection system for converting radiation of the scanning spot on the information plane of the information signal and the error signal of the tracking and monitoring system, managed what erom mode, wherein the tracking system is configured to hold the scanning spot at one edge of the scanned track in the second mode.

2. The device under item 1, characterized in that it is a tracking system configured to hold the second mode of the center of the scanning spot at a distance from the centerline that is designed to scan, track, and this distance is 1/5 of the pitch of the track of the optical media recording of the second type.

3. The device under item 1 or 2, characterized in that it tracking system has an electric circuit with two inputs, the first of which is designed to feed him the error signal of the tracking, and the second input is used to feed him through the switch of the DC signal in the second mode.

4. The device according to p. 3, characterized in that it comprises a circuit for determining the signal quality of the reproduction of information and to generate DC signal, which depends on the above.

5. The device under item 1 or 2, characterized in that it comprises means for generating a tracking beam from the lens system forming the tracking spots are located offset from the Deposit tracking for converting radiation tracking spot on the information plane in the error signal tracking when this device is put a switch with two inputs and one output, which is connected with the control input of the tracking system, the first switch input coupled to the output switch in the first mode and the output of the circuit forming and outputting the error signal tracking based on the output signals of the first detection system, and the second switch input coupled to the output switch to the second mode and padding scheme forming and outputting the error signal tracking based on the output signals of the first detection system and the detection system monitoring.

6. The device under item 1 or 2, characterized in that it contains means for generating two beams of tracking that using a lens system to form two tracking spots are shifted in the transverse direction and located on both sides of the scanning spot, and two detection systems tracking for receiving radiation of two tracking spots from the information plane, the device entered the switch with two inputs and one output, which is connected with the control input of the tracking system, the first switch input coupled to the output switch in the first mode and the output of the circuit forming the second input of the switch is connected to the output of the switch to the second mode and padding scheme for the formation of the error signal tracking based on the output signals of the first detection system and one of the detection systems tracking.

7. The device under item 5 or 6, characterized in that it is made with the possibility of following one of the tracking spots just on the edge of the track.

8. The device according to p. 7, characterized in that in it the second wavelength is two times bigger than the first wavelength, and the distance in the transverse direction between the two tracking spots within 1.5 times the pitch of the track of the optical media recording of the first type.

9. Device according to one of paragraphs.1, 2, 5 or 6, characterized in that at least one of the detection systems contains two detector outputs are connected to respective inputs entered in the device of the differential amplifier.

10. Device according to one of paragraphs.1, 2, 5 or 6, characterized in that it comprises a discriminator type, the output of which is connected to the tracking system to install the device in a mode corresponding to the type of optical recording media, designed to play with it.

 

Same patents:

The invention relates to techniques for recording and/or reproduction of information with mutual relative movement of the optical medium and the optical head and can be used in the information technology, such as digital video recording devices, devices, digital audio, optical external storage devices of computers

The invention relates to automation and the accumulation of information by optical means, in particular to the technique of recording-playback information, and can be used in audio and video players, and other means to provide optical recording-reproduction of information

FIELD: optical discs.

SUBSTANCE: sector header on optical disc has first and second headers, recorded in a way to deflect from track middle in opposite directions, and have address areas, wherein address signals are recorded and synchronous signals areas for detecting address signals. Playback signal generator includes photo-detector, having radial couples of detecting elements. Playback signal includes total signals V1 or V2 of radial couples of detecting elements, total signal RF_sum of detecting elements, counter-phase signal RF_pp of detecting elements, from optical signal reflected from disc. Header area detector generates header area signal, containing header area from playback signal received from playback signal generator. Level detectors for first and second synchronous signals receive playback signal from playback signal generator and perform detection of value of first synchronous signal in first header and value of second synchronous signal in second header. Balance calculator calculates balance value of first and second synchronous signals. Determining of error of slant is performed in accordance to balance value.

EFFECT: higher efficiency.

2 cl, 15 dwg

FIELD: optical record/play devices.

SUBSTANCE: data area on disc is divided into sectors. Each sector header has first header and second header, recorded in a way to deflect from track middle in opposite directions. Said first and second headers have address areas, wherein sectors address signals and synchronous signals areas are recorded, wherein synchronous signals for detecting address signals are recorded. First value of synchronous clock signal is detected from first header and is a Lvfo1. second value of synchronous clock signal is detected from second header and is a Lvfo3. relation of first value Lvfo1 to second value Lvfo3 is a previously set limited value.

EFFECT: higher precision of error detection.

7 cl, 15 dwg

FIELD: optical data carriers.

SUBSTANCE: method includes focusing main and auxiliary laser emission beams on working surface, continuous determining of distance to recording point and correcting of main laser focus accordingly to change of distance from recording point. Determining space from recording point is performed during space combination of optical paths of two falling beams, with measurement of alteration of energy distribution of auxiliary reflected beam in registration plane due to forming of astigmatism of reflected beam.

EFFECT: higher quality, higher precision, higher efficiency.

3 cl, 3 dwg

FIELD: optical data carriers.

SUBSTANCE: from optical disk, on which standard samples of similar length are recorded in a way to deviate from middle of track in opposite directions, signals are reproduced, which are detected from standard samples. On basis of determined values of detected signals value of balance value is determined, on basis of which servo error is detected. As standard samples, "vfo" template signals recorded on disk can be used. Values of balanced values, received for adjoining sectors, can be brought to average. Balance value for detection of incline error can be determined on basis of subtraction signal RF_pp, which is signal of subtraction V2-V1, where V1, V2 - signals from radial couples of photo-detector.

EFFECT: more stable servo control, maintained optimal state for recording and reproduction.

11 cl, 15 dwg

FIELD: optical data carriers.

SUBSTANCE: from optical disk, on which standard samples of similar length are recorded in a way to deviate from middle of track in opposite directions, signals are reproduced, which are detected from standard samples. On basis of determined values of detected signals value of balance value is determined, on basis of which servo error is detected. As standard samples, "vfo" template signals recorded on disk can be used. Values of balanced values, received for adjoining sectors, can be brought to average. Balance value for detection of incline error can be determined on basis of subtraction signal RF_pp, which is signal of subtraction V2-V1, where V1, V2 - signals from radial couples of photo-detector.

EFFECT: more stable servo control, maintained optimal state for recording and reproduction.

11 cl, 15 dwg

FIELD: optical data carriers.

SUBSTANCE: optical scanning device for information carrier has emission source, collimator lens assembly, objective lens assembly and drive for moving assembly of collimator lens, drive has moving and immovable portions, movement of which relatively to each other is limited, while immovable and moving portions of drive are in the same magnetic circuit, having immovable magnetizable portion contained in moving portion of drive, aforementioned first and second positions of which are balanced positions. Device is made with possible control by means of adjustment of electric current by interaction between electromagnetic field of inductiveness coil and magnetic field of constant magnet.

EFFECT: possible production of reliable and functional drive for moving collimator assembly.

2 cl, 5 dwg

FIELD: focus adjustment devices, possible use in devices for recording/reproducing optical disks.

SUBSTANCE: focus adjusting device is used for focusing the light emitted by light source onto recording layer of optical disk by means of an objective, wherein the zone of coverage to achieve focusing is determined from the following: lower boundary is determined on the basis of average length of impulse series; and upper boundary is determined on basis of optical disk track step.

EFFECT: increased focusing precision.

5 cl, 13 dwg

FIELD: physics, computer engineering.

SUBSTANCE: according to the present invention device for optical disk is arranged with the possibility to read data from optical disk having multiple layers of information record, including the first layer of information record, distance of which from disk surface is relatively small, and the second layer of information record, distance of which from disk surface is relatively large. This device on optical disk comprises the following: section of focus adjustment that stipulates for location of light beam convergence point on randomly selected layer of information record of optical disk; section of tracking that stipulates for location of light beam convergence point on previously specified path of information record layer; and section for specification of amplification ratio arranged with the possibility to modify amplitude-frequency characteristic of at least one from focus adjustment section and tracking section. Section of amplification ratio switching sets cutoff frequency value in advance (frequency, at which amplification ratio is equal to 0 dB), when reading data from the first layer of information record by less than value of cutoff frequency in process of data reading from the second layer of information record.

EFFECT: provision of possibility to read data from optical disk having multiple layers of information record, including the first layer of information record, distance of which from disk surface is relatively small, and the second layer of information record, distance of which from disk surface is relatively large.

10 cl, 9 dwg

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