Optical disk device and recording / playback device

Abstract

An optical disk device (2) comprises: an optical pickup (4) which includes a first laser beam source (10) that emits a laser beam, an objective lens (24) that converges, onto an optical disk (8), the laser beam emitted from the first laser beam source (10), and a light receiving element (30) that receives reflected light from the optical disk (8) and that performs photoelectric conversion of the received reflected light so as to output a light reception signal; an FS signal generation unit (54) which on the basis of the light reception signal from the light receiving element (30) generates an FS signal that indicates the amount of the reflected light from the optical disk (8); and a dirtiness determination unit (56) which, when the peak level of the FS signal is less than a dirtiness determination threshold, determines that the optical pickup (4) is dirty and controls the light receiving element (30) such that the peak level of the light reception signal from the light receiving element (30) is increased.

Description

[Technical field]

[0001] The present disclosure relates to an optical disc device and a recording / playback device. [Background technology]

[0002] There is known an optical disc device that records or reproduces information on an optical disc by irradiating the optical disc with a laser beam (see, for example, Patent Documents 1 and 2). This type of optical disc device includes an optical pickup and a controller. The optical pickup irradiates the optical disc with a laser beam, receives reflected light from the optical disc, and outputs a light reception signal according to the received reflected light. The controller generates a focus error signal, a tracking error signal, and the like, based on the light reception signal from the optical pickup. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-228401 A [Patent Document 2] JP 2009-283100 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides an optical disk device and a recording / reproducing device that can accurately record or reproduce information on an optical disk even if the optical pickup becomes dirty. [Means for solving the problem]

[0005] The optical disc device of the present disclosure is an optical disc device that records or reproduces information on an optical disc by irradiating the optical disc with laser light, and is equipped with an optical pickup including a laser light source that emits laser light, an objective lens that converges the laser light emitted from the laser light source onto the optical disc, and a light receiving element that receives reflected light from the optical disc and outputs a received light signal by photoelectrically converting the received reflected light, a light intensity signal generation unit that generates a light intensity signal indicating the amount of reflected light from the optical disc based on the light receiving signal from the light receiving element, and a dirt determination unit that determines that dirt has occurred on the optical pickup if the peak level of the light intensity signal is less than a first threshold value, and controls the laser light source or the light receiving element so as to increase the peak level of the light receiving signal from the light receiving element. Effect of the Invention

[0006] According to the optical disc device and the like of the present disclosure, even if the optical pickup becomes dirty, it is possible to accurately record or reproduce information on the optical disc. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a configuration of an optical disc device according to the first embodiment. [Diagram 2] FIG. 2 is a diagram showing a light receiving element of the optical disc device according to the first embodiment. [Diagram 3] FIG. 3 is a flowchart showing the flow of operations of the optical disc device according to the first embodiment. [Figure 4] FIG. 4 is a flowchart specifically showing the process of step S102 in FIG. [Diagram 5] FIG. 5 is a diagram illustrating the operation of the optical disc device according to the first embodiment. [Figure 6] FIG. 6 is a diagram showing a configuration of an optical disc device according to the second embodiment. [Figure 7] FIG. 7 is a flowchart showing the flow of operations of the optical disc device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, the embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

[0009] The inventors provide the accompanying drawings and the following description so that those skilled in the art can fully understand the present disclosure, and do not intend for them to limit the subject matter described in the claims.

[0010] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to FIGS.

[0011] [1-1. Configuration of optical disk device] First, the configuration of an optical disc device 2 according to the first embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a diagram showing the configuration of an optical disc device 2 according to the first embodiment. Fig. 2 is a diagram showing a light receiving element 30 of the optical disc device 2 according to the first embodiment.

[0012] 1, an optical disc device 2 according to the first embodiment includes an optical pickup 4 and a control unit 6. The optical disc device 2 is mounted on, for example, a BD (Blu-ray (registered trademark) Disc) recorder (an example of a recording and reproducing device) capable of recording and reproducing information on an optical disc 8. Although not shown, the optical disc device 2 is connected to a display such as a liquid crystal television receiver.

[0013] The optical disc 8 includes a BD, a DVD (Digital Versatile Disc), and a CD (Compact Disc). A BD is an example of a first optical disc, and a DVD and a CD are examples of a second optical disc. When the optical disc 8 is inserted into the optical disc device 2, the optical disc 8 is rotated by a spindle motor (not shown) with the vicinity of the radial center of the optical disc 8 chucked.

[0014] The optical pickup 4 is an optical pickup unit (OPU) for recording or reproducing information on the optical disc 8. The optical pickup 4 has a first laser light source 10, a second laser light source 12, a first beam splitter 14, a second beam splitter 15, a collimator lens 16, a reflector 18, a front monitor 20, a quarter-wave plate 22, an objective lens 24, a lens actuator 26, a cylindrical lens 28, and a light receiving element 30.

[0015] The first laser light source 10 is a laser diode (LD) that emits a laser beam for BD having a wavelength of 405 nm. The laser beam for BD is an example of the first laser beam.

[0016] The second laser light source 12 is a two-wavelength integrated LD capable of emitting a laser light for DVD with a wavelength of 650 nm and a laser light for CD with a wavelength of 780 nm. The laser light for DVD and the laser light for CD are examples of the second laser light. Note that in the present embodiment, the second laser light source 12 is a two-wavelength integrated LD, but is not limited thereto. A third laser light source (not shown) may be provided separately from the second laser light source 12, and the second laser light source 12 may be an LD that emits a laser light for DVD, and the third laser light source may be an LD that emits a laser light for CD.

[0017] The first beam splitter 14 reflects the laser light from the second laser light source 12. The laser light reflected by the first beam splitter 14 is sent to the second beam splitter 15.

[0018] The second beam splitter 15 transmits the laser light from the second laser light source 12 and reflects the laser light from the first laser light source 10. The laser light transmitted or reflected by the second beam splitter 15 is sent to a collimator lens 16.

[0019] The collimator lens 16 converts the laser light sent from the second beam splitter 15 into parallel light. The laser light converted into parallel light by the collimator lens 16 is sent to a reflector 18.

[0020] The reflector 18 reflects the laser light sent from the collimator lens 16 and guides it to the quarter-wave plate 22. The reflector 18 also transmits a part of the laser light sent from the collimator lens 16 and guides it to the front monitor 20.

[0021] The front monitor 20 generates an electrical signal according to the intensity of the incident laser light, and controls the intensity of each laser light emitted from the first laser light source 10 and the second laser light source 12 so that the electrical signal is kept constant.

[0022] The quarter-wave plate 22 has a function of converting linearly polarized light into circularly polarized light and converting circularly polarized light into linearly polarized light. The quarter-wave plate 22 is provided to prevent the laser light reflected by the optical disc 8 from returning to the first laser light source 10 and the second laser light source 12.

[0023] The objective lens 24 converges the laser light sent from the quarter-wave plate 22. The laser light converged by the objective lens 24 is reflected by the recording surface 8a of the optical disc 8.

[0024] The lens actuator 26 drives the objective lens 24 in a focus direction, a tracking direction, etc. The lens actuator 26 is controlled by a focus control unit 44 and a tracking control unit 50, which will be described later.

[0025] The laser light (reflected light) reflected by the recording surface 8a of the optical disc 8 travels back through the objective lens 24, the quarter-wave plate 22, the reflector 18, the collimator lens 16, the second beam splitter 15 and the first beam splitter 14, and is incident on the light receiving element 30 via the cylindrical lens 28.

[0026] The cylindrical lens 28 generates astigmatism in the laser light sent from the first beam splitter 14. The laser light transmitted through the cylindrical lens 28 is sent to the light receiving element 30.

[0027] The light receiving element 30 is an optoelectronic integrated circuit (OEIC) and includes a received light signal generating section 32 and a received light signal gain adjusting section .

[0028] The light-receiving signal generating unit 32 receives reflected light from the optical disc 8 and generates a light-receiving signal by photoelectrically converting the received reflected light. Specifically, as shown in Fig. 2, the light-receiving signal generating unit 32 has photodiodes 36a, 36b, 36c, and 36d (36a to 36d) arranged in, for example, two rows and two columns. The light-receiving signal generating unit 32 generates a light-receiving signal by photoelectrically converting the reflected light received by each of the photodiodes 36a to 36d individually.

[0029] The received light signal gain adjuster 34 amplifies the received light signal generated by the received light signal generator 32 at a predetermined amplification factor. The received light signal gain adjuster 34 can switch the predetermined amplification factor, for example, between three levels (high level, middle level, and low level). The received light signal gain adjuster 34 outputs the received light signal amplified at the predetermined amplification factor to the control unit 6.

[0030] The control unit 6 has an A / D conversion section 38, an FE signal generation section 40, an AGC (Automatic Gain Control) circuit 42, a focus control section 44, a TE signal generation section 46, an AGC circuit 48, a tracking control section 50, an RF signal generation section 52, an FS signal generation section 54, a disk determination section 55, a dirt determination section 56, and an LD classification section 57. The control unit 6 is composed of, for example, a DSP (Digital Signal Processor).

[0031] The A / D conversion unit 38 converts the received light signal from the light receiving element 30 from an analog signal to a digital signal. The A / D conversion unit 38 outputs the converted digital received light signal to the FE signal generation unit 40, the TE signal generation unit 46, the RF signal generation unit 52, and the FS signal generation unit 54.

[0032] The FE signal generating unit 40 generates a focus error signal (hereinafter referred to as "FE signal") based on the light receiving signal from the A / D conversion unit 38. Specifically, as shown in Fig. 2, the FE signal generating unit 40 calculates the difference between a sum (A+C) of a light receiving signal A received by the photodiode 36a of the light receiving element 30 and a light receiving signal C received by the photodiode 36c, and a sum (B+D) of a light receiving signal B received by the photodiode 36b and a light receiving signal D received by the photodiode 36d, thereby generating an FE signal = (A+C) - (B+D). The FE signal generating unit 40 outputs the generated FE signal to the AGC circuit 42.

[0033] The AGC circuit 42 generates a normalized focus error signal (hereinafter referred to as "normalized FE signal") which is the ratio (FE signal / FS signal) of the FE signal from the FE signal generating unit 40 and the FS signal from the FS signal generating unit 54. As a result, the AGC circuit 42 performs a process (automatic gain control: AGC) of normalizing the amplitude of the FE signal to a constant value regardless of the amount of reflected light. The AGC circuit 42 outputs the normalized FE signal to the focus control unit 44 and the disc determination unit 55. The AGC circuit 42 is an example of a first automatic gain controller.

[0034] The focus control unit 44 generates a focus control signal for controlling the driving of the lens actuator 26 based on the normalized FE signal from the AGC circuit 42, and outputs the generated focus control signal to the lens actuator 26. The lens actuator 26 moves the objective lens 24 in the focus direction (a direction approaching and moving away from the recording surface 8a of the optical disc 8) based on the focus control signal from the focus control unit 44. This performs focus control to adjust the position of the objective lens 24 in the focus direction so that the laser light emitted from the objective lens 24 is converged on the recording surface 8a of the optical disc 8.

[0035] The TE signal generating unit 46 generates a tracking error signal (hereinafter, referred to as "TE signal") based on the light receiving signal from the A / D conversion unit 38. Specifically, as shown in Fig. 2, the TE signal generating unit 46 calculates the difference between the sum (A+D) of the light receiving signal A received by the photodiode 36a of the light receiving element 30 and the light receiving signal D received by the photodiode 36d, and the sum (B+C) of the light receiving signal B received by the photodiode 36b and the light receiving signal C received by the photodiode 36c, thereby generating a TE signal = (A+D) - (B+C). The TE signal generating unit 46 outputs the generated TE signal to the AGC circuit 48.

[0036] The AGC circuit 48 generates a normalized tracking error signal (hereinafter referred to as "normalized TE signal") which is the ratio (TE signal / FS signal) of the TE signal from the TE signal generating unit 46 and the FS signal from the FS signal generating unit 54. As a result, the AGC circuit 48 performs a process of normalizing the amplitude of the TE signal to a constant value. The AGC circuit 48 outputs the normalized TE signal to the tracking control unit 50. The AGC circuit 48 is an example of a second automatic gain controller.

[0037] The tracking control unit 50 generates a tracking control signal for controlling the driving of the lens actuator 26 based on the normalized TE signal from the AGC circuit 48, and outputs the generated tracking control signal to the lens actuator 26. The lens actuator 26 moves the objective lens 24 in the tracking direction (radial direction of the optical disc 8) based on the tracking control signal from the tracking control unit 50. This performs tracking control to adjust the position of the objective lens 24 in the tracking direction so that the laser light from the objective lens 24 follows the track on the recording surface 8a of the optical disc 8.

[0038] The RF signal generating unit 52 generates an RF (Radio Frequency) signal for reproducing information recorded on the optical disc 8 based on the light receiving signal from the A / D converting unit 38. The RF signal is a reproduction signal including a video signal and an audio signal. The RF signal generating unit 52 outputs the generated RF signal to a display via a demodulation signal processing circuit (not shown) and a video decoding circuit (not shown).

[0039] The FS signal generating unit 54 generates a focus sum signal (hereinafter, referred to as "FS signal") indicating the amount of reflected light from the optical disk 8 based on the light receiving signal from the A / D conversion unit 38. Specifically, as shown in FIG. 2, the FS signal generating unit 54 generates an FS signal = A + B + C + D by adding a light receiving signal A received by the photodiode 36a of the light receiving element 30, a light receiving signal B received by the photodiode 36b, a light receiving signal C received by the photodiode 36c, and a light receiving signal D received by the photodiode 36d. The FS signal generating unit 54 outputs the generated FS signal to the AGC circuit 42, the AGC circuit 48, and the dirt determining unit 56. The FS signal is an example of a light amount signal, and the FS signal generating unit 54 is an example of a light amount signal generating unit.

[0040] The disc determination unit 55 determines the type of the optical disc 8 based on information from the LD classification unit 57 indicating, for example, that "a laser beam for BD is currently being irradiated", by comparing the double amplitude (PP amplitude) of the normalized FE signal from the AGC circuit 42 with a BD determination threshold (an example of a second threshold) or the like. Note that the double amplitude means the amplitude of the peak on the time axis (peak-to-peak).

[0041] In response to the determination result of the disc determination unit 55, for example, a result that "the current optical disc is a BD and is consistent with the type of laser light", if the peak level of the FS signal is less than the dirt determination threshold (an example of a first threshold) switched by the LD classification unit 57, the dirt determination unit 56 determines that dirt (for example, cigarette dirt, etc., described later) has occurred on the optical pickup 4, and controls the light receiving signal gain adjustment unit 34 of the light receiving element 30 so as to increase a predetermined amplification factor. The dirt determination threshold is a different value for each type (BD, DVD, and CD) of the optical disc 8, and is switched by the LD classification unit 57. For example, when the LD classification unit 57 determines that the type of laser light is a laser light for BD, it switches to a dirt determination threshold for BD. Here, for example, only when the determination result by the LD classification unit 57 is a laser light for BD and the determination result by the disc determination unit 55 is a BD, the dirt determination unit 56 operates.

[0042] The LD classification unit 57 determines the type of laser light (laser light for BD, laser light for DVD, laser light for CD) emitted from the first laser light source 10 or the second laser light source 12. The LD classification unit 57 outputs information indicating the determined type of laser light (for example, information indicating that "laser light for BD is currently being emitted") to the disc determination unit 55 and the dirt determination unit 56.

[0043] [1-2. Operation of optical disk device] Next, the operation of the optical disc device 2 according to the first embodiment will be described with reference to Fig. 3 to Fig. 5. Fig. 3 is a flowchart showing the flow of the operation of the optical disc device 2 according to the first embodiment. Fig. 4 is a flowchart specifically showing the process of step S102 in Fig. 3. Fig. 5 is a diagram for explaining the operation of the optical disc device 2 according to the first embodiment.

[0044] As shown in FIG. 3, first, the user places the optical disc 8 on a tray (not shown) of the optical disc device 2, and then inserts the optical disc 8 placed on the tray into the optical disc device 2 (S101).

[0045] Next, the type of the optical disc 8 placed on the tray is determined (S102). Hereinafter, the process of step S102 in Fig. 3 (processing for determining the type of the optical disc 8) will be specifically described with reference to Figs.

[0046] 5, the first case is when the optical disc 8 is a BD and there is no tobacco stain on the optical pickup 4. The second case is when the optical disc 8 is a BD and there is tobacco stain on the optical pickup 4. The third case is when the optical disc 8 is something other than a BD (including when the optical disc 8 is not inserted inside the optical disc device 2). Moreover, tobacco stain refers to stains on the inside of the optical pickup 4 that occur when cigarette smoke gets into the inside of the optical pickup 4.

[0047] As shown in Fig. 4, first, the optical disc 8 is irradiated with a laser beam for BD from the first laser light source 10 (S1021). At this time, as shown in Fig. 5(a), the lens actuator 26 moves the objective lens 24 in a direction approaching the recording surface 8a of the optical disc 8.

[0048] The AGC circuit 42 generates a normalized FE signal (FIG. 5(d)) by calculating the ratio (FE signal / FS signal) between the FE signal (FIG. 5(b)) from the FE signal generating unit 40 and the FS signal (FIG. 5(c)) from the FS signal generating unit 54. The disc determination unit 55 determines whether or not both amplitudes PL1 of the normalized FE signal generated by the AGC circuit 42 are equal to or greater than a BD determination threshold value TH1, based on information indicating that "BD laser light is currently being emitted" from the LD classification unit 57 (S1022).

[0049] As shown in the first and second cases in (d) of Figure 5, if both amplitudes PL1 of the normalized FE signal are greater than or equal to the BD determination threshold TH1 (YES in S1022), the disc determination unit 55 determines that the type of the optical disc 8 is BD (S1023).

[0050] As shown in (b) and (c) of FIG. 5, both amplitudes of the FE signal and the peak level of the FS signal in the second case are lower than both amplitudes of the FE signal and the peak level of the FS signal in the first case. This is because tobacco stains are generated inside the optical pickup 4 in the second case. However, the rate of decrease of the FE signal and the FS signal in the second case relative to the FE signal and the FS signal in the first case is almost the same, so the ratio of the FE signal to the FS signal (FE signal / FS signal) is almost constant in the first and second cases. Therefore, as shown in the first and second cases in (d) of FIG. 5, when the optical disc 8 is a BD, both amplitudes PL1 of the normalized FE signal are equal to or greater than the BD determination threshold value TH1, regardless of the presence or absence of tobacco stains on the optical pickup 4.

[0051] Returning to step S1022, as shown in the third case in (d) of FIG. 5, when both amplitudes PL2 of the normalized FE signal are less than the BD determination threshold value TH1 (NO in S1022), the disc determination unit 55 determines that the type of the optical disc 8 is other than BD (S1024). In this case, the first laser light source 10 stops emitting light, and the lens actuator 26 moves the objective lens 24, which has moved in a direction approaching the recording surface 8a of the optical disc 8, in a direction away from the recording surface 8a of the optical disc 8. After that, the laser light for DVD from the second laser light source 12 is irradiated onto the optical disc 8 (S1025). At this time, the lens actuator 26 moves the objective lens 24 in a direction approaching the recording surface 8a of the optical disc 8.

[0052] As described above, the disc determination unit 55 determines whether or not both amplitudes of the normalized FE signal generated by the AGC circuit 42 are equal to or greater than the DVD determination threshold value based on the information from the LD classification unit 57 indicating that “DVD laser light is currently being emitted” (S1026).

[0053] If both amplitudes of the normalized FE signal are equal to or greater than the DVD determination threshold value (YES in S1026), the disc determination unit 55 determines that the type of the optical disc 8 is a DVD (S1027).

[0054] On the other hand, if both amplitudes of the normalized FE signal are less than the DVD determination threshold (NO in S1026), the disc determination unit 55 determines that the type of the optical disc 8 is other than DVD (S1028). In this case, the optical disc 8 is irradiated with a laser beam for CD from the second laser light source 12 (S1029). At this time, the lens actuator 26 moves the objective lens 24 in a direction away from the recording surface 8a of the optical disc 8, and then moves the objective lens 24 in a direction approaching the recording surface 8a of the optical disc 8, as described above.

[0055] As described above, the disc determination unit 55 determines whether or not both amplitudes of the normalized FE signal generated by the AGC circuit 42 are equal to or greater than the CD determination threshold value based on the information from the LD classification unit 57 indicating that “CD laser light is currently being irradiated” (S1030).

[0056] If both amplitudes of the normalized FE signal are equal to or greater than the CD determination threshold value (YES in S1030), the disc determination unit 55 determines that the type of the optical disc 8 is a CD (S1031).

[0057] On the other hand, if both amplitudes of the normalized FE signal are less than the CD determination threshold (NO in S1030), the disc determination unit 55 determines that the optical disc 8 is not present, that is, that the optical disc 8 is not inserted inside the optical disc device 2 (S1032). In this manner, the process of determining the type of the optical disc 8 ends.

[0058] Returning to the flowchart of Fig. 3, hereinafter, a description will be given of the cases where it is determined in step S102 that the type of the optical disc 8 is a BD (first and second cases in Fig. 5). After step S102, the disc determination unit 55 determines the number of layers of the optical disc 8 (for example, one, two, or three layers) based on the number of S-shaped curves included in the normalized FE signal (S103).

[0059] Next, the dirt determination unit 56 provisionally determines the predetermined amplification factor in the light receiving signal gain adjustment unit 34 of the light receiving element 30 to be, for example, a middle level based on the determination results in steps S102 and S103 (S104).

[0060] Next, the dirt determining section 56 determines whether or not the peak level of the FS signal from the FS signal generating section 54 is equal to or higher than the dirt determining threshold value TH2 (S105).

[0061] 5(c), when the peak level PL3 of the FS signal is equal to or higher than the stain determination threshold TH2 (YES in S105), the stain determination unit 56 determines that no cigarette stains have occurred inside the optical pickup 4 (S106). In this case, the stain determination unit 56 maintains the predetermined amplification factor in the light receiving signal gain adjustment unit 34 of the light receiving element 30 at, for example, a middle level (S107).

[0062] Thereafter, the disk determination unit 55 determines whether the optical disk 8 is a ROM system or an R / RW system based on a comparison between the PP signal (a signal generated by a push-pull method) of the TE signal and the DPD signal (a signal generated by a phase difference method) (S108). The dirt determination unit 56 also takes into consideration the determination result in step S108, and finally determines the predetermined amplification factor in the light receiving signal gain adjustment unit 34 of the light receiving element 30 (S109), and ends the process.

[0063] Returning to step S105, as shown in the second case in FIG. 5C, if the peak level PL4 of the FS signal is less than the dirt determination threshold TH2 (NO in S105), the dirt determination unit 56 determines that tobacco dirt has occurred inside the optical pickup 4 (S110). This is because the amount of reflected light received by the light receiving element 30 decreases due to the tobacco dirt occurring on the optical system (objective lens 24, cylindrical lens 28, light receiving element 30, etc.) of the optical pickup 4, and the peak level of the light receiving signal output from the light receiving element 30 decreases. In this case, the dirt determination unit 56 increases the predetermined amplification factor in the light receiving signal gain adjustment unit 34 of the light receiving element 30, for example, from a middle level to a high level (S111).

[0064] This makes it possible to bring the peak level of the light receiving signal output from the light receiving element 30 closer to the peak level of the light receiving signal when no tobacco stains are present inside the optical pickup 4. As a result, it is possible to increase the peak levels of the FE signal generated by the FE signal generating unit 40, the TE signal generated by the TE signal generating unit 46, the RF signal generated by the RF signal generating unit 52, and the FS signal generated by the FS signal generating unit 54. After step S111, the process proceeds to step S108 described above.

[0065] In the above-mentioned steps S103 to S109, the case where the type of the optical disc 8 is determined to be a BD in step S102 has been described, but the above also applies to the case where the type of the optical disc 8 is determined to be a DVD or a CD in step S102. That is, when the disc determination section 55 determines that the type of the optical disc 8 is a DVD (or CD) and the peak level of the FS signal is less than the dirt determination threshold, the dirt determination section 56 determines that dirt has occurred on the optical pickup 4, and controls the light receiving signal gain adjustment section 34 to increase a predetermined amplification factor.

[0066] [1-3. Effects] In a conventional optical disc device, when the optical pickup is dirty, the peak level of the light receiving signal from the light receiving element is reduced, and the peak levels of the FE signal, TE signal, RF signal, and FS signal are reduced. As a result, for example, focus control and tracking control cannot be performed correctly, the RF signal is deteriorated, and information cannot be recorded or reproduced accurately on the optical disc.

[0067] In contrast, in this embodiment, the optical disc device 2 is an optical disc device that records or reproduces information on the optical disc 8 by irradiating the optical disc 8 with laser light. The optical disc device 2 includes an optical pickup 4 including a first laser light source 10 and a second laser light source 12 (laser light source) that emit laser light, an objective lens 24 that converges the laser light emitted from the first laser light source 10 and the second laser light source 12 on the optical disc 8, and a light receiving element 30 that receives reflected light from the optical disc 8 and outputs a light receiving signal by photoelectrically converting the received reflected light, an FS signal generating unit 54 (light amount signal generating unit) that generates an FS signal (light amount signal) indicating the light amount of reflected light from the optical disc 8 based on the light receiving signal from the light receiving element 30, and a dirt determining unit 56 that determines that dirt has occurred on the optical pickup 4 when the peak level of the FS signal is less than a dirt determining threshold (first threshold), and controls the light receiving element 30 so as to increase the peak level of the light receiving signal from the light receiving element 30.

[0068] According to this, when the dirt determination unit 56 determines that dirt has occurred on the optical pickup 4, it controls the light receiving element 30 so as to increase the peak level of the light receiving signal from the light receiving element 30. This makes it possible to bring the peak level of the light receiving signal from the light receiving element 30 closer to the peak level of the light receiving signal when no tobacco dirt has occurred inside the optical pickup 4. As a result, for example, it is possible to increase the peak levels of the FE signal generated by the FE signal generation unit 40, the TE signal generated by the TE signal generation unit 46, the RF signal generated by the RF signal generation unit 52, and the FS signal generated by the FS signal generation unit 54, and it is possible to record or reproduce information on the optical disc 8 with high accuracy.

[0069] In addition, in this embodiment, the optical disc device 2 further includes an FE signal generating unit 40 that generates an FE signal based on the light receiving signal from the light receiving element 30, and an AGC circuit 42 (first automatic gain controller) that generates a normalized FE signal which is the ratio between the FE signal and the FS signal.

[0070] According to this, by appropriately updating the parameters of the automatic gain control of the AGC circuit 42, it is possible to increase the peak level of the light receiving signal from the light receiving element 30 and to amplify the normalized FE signal auxiliary. As a result, information can be recorded or reproduced on the optical disc 8 with even greater accuracy.

[0071] In the present embodiment, the optical disc 8 includes different types of BD (first optical disc) and DVD (second optical disc). The laser light source includes a first laser light source 10 that emits a laser light for BD (first laser light) to be irradiated to a BD, and a second laser light source 12 that emits a laser light for DVD (second laser light) to be irradiated to a DVD. The optical disc device 2 further includes a disc determination unit 55 that, when the first laser light source 10 emits a laser light for BD, determines whether or not the type of the optical disc 8 is a BD based on a comparison between both amplitudes of the normalized FE signal and a BD determination threshold (second threshold). When the determination result of the LD classification unit 57 is the laser light for BD and the disc determination unit 55 determines that the type of the optical disc 8 is a BD, the dirt determination unit 56 determines that dirt has occurred on the optical pickup 4 when the peak level of the FS signal is less than the dirt determination threshold.

[0072] 5(c), it may not be possible to distinguish whether the optical disc 8 is a BD and the optical pickup 4 is dirty, or whether the optical disc 8 is something other than a BD, simply by comparing the peak level of the FS signal with the dirt determination threshold. Therefore, after determining that the type of optical disc 8 is a BD, it is possible to accurately determine whether the optical pickup 4 is dirty by comparing the peak level of the FS signal with the dirt determination threshold.

[0073] In this embodiment, the light receiving element 30 includes a light receiving signal generator 32 that receives reflected light from the optical disc 8 and generates a light receiving signal by photoelectrically converting the received reflected light, and a light receiving signal gain adjuster 34 that amplifies the generated light receiving signal by a predetermined amplification factor. When the determination result of the LD type unit 57 is a laser beam for BD and the type of the optical disc 8 is determined to be BD by the disc determination unit 55, the dirt determination unit 56 determines that dirt has occurred on the optical pickup 4 if the peak level of the FS signal is less than the dirt determination threshold, and controls the light receiving signal gain adjuster 34 to increase the predetermined amplification factor.

[0074] This makes it possible to easily increase the peak level of the light receiving signal from the light receiving element 30.

[0075] [1-4. Modifications] In this embodiment, for example, when the disc determination unit 55 determines that the type of the optical disc 8 is BD and the peak level of the FS signal is less than the dirt determination threshold, the dirt determination unit 56 determines that dirt has occurred on the optical pickup 4 and controls the received light signal gain adjustment unit 34 to increase the predetermined amplification factor, but it may also be configured as follows.

[0076] That is, in this modified example, the optical disc device 2 further includes a TE signal generating unit 46 that generates a TE signal based on the light receiving signal from the light receiving element 30, and an AGC circuit 48 (second automatic gain controller) that generates a normalized TE signal which is the ratio between the TE signal and the FS signal.

[0077] According to this, by appropriately updating the parameters of the automatic gain control of the AGC circuit 48, it is possible to increase the peak level of the light receiving signal from the light receiving element 30 and to amplify the normalized TE signal as an auxiliary. As a result, information can be recorded or reproduced on the optical disc 8 with even greater accuracy.

[0078] (Embodiment 2) [2-1. Optical disk device configuration] The configuration of an optical disc device 2A according to the second embodiment will be described with reference to Fig. 6. Fig. 6 is a diagram showing the configuration of an optical disc device 2A according to the second embodiment. Note that in this embodiment, the same components as those in the first embodiment are given the same reference numerals and the description thereof will be omitted.

[0079] 6, in the optical disc device 2A according to the second embodiment, the process by the dirt determination section 56A of the control unit 6A is different from that in the first embodiment. Specifically, when the type of the optical disc 8 is determined by the disc determination section 55 and the peak level of the FS signal is less than the dirt determination threshold, the dirt determination section 56A determines that the optical pickup 4 is dirty, and controls the first laser light source 10 and the second laser light source 12 to increase the intensities of the laser beams emitted from the first laser light source 10 and the second laser light source 12.

[0080] [2-2. Operation of optical disk device] Next, the operation of the optical disc device 2A according to the second embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing the flow of the operation of the optical disc device 2A according to the second embodiment. In the flowchart of Fig. 7, the same processes as those in the flowchart of Fig. 3 described above are given the same step numbers, and their explanations will be omitted.

[0081] As in the first embodiment, steps S101 to S105 are executed, and if the peak level of the FS signal is equal to or higher than the stain determination threshold (YES in S105), the stain determination unit 56A determines that no cigarette stains have occurred inside the optical pickup 4 (S106). In this case, the stain determination unit 56A controls the first laser light source 10 and the second laser light source 12 so as to maintain the intensity of the laser light emitted from the first laser light source 10 and the second laser light source 12 (S201). Then, the process proceeds to step S108 described above.

[0082] Returning to step S105, if the peak level of the FS signal is less than the stain determination threshold (NO in S105), the stain determination unit 56A determines that tobacco stains have occurred inside the optical pickup 4 (S110). In this case, the stain determination unit 56A controls the first laser light source 10 and the second laser light source 12 so as to increase the intensities of the laser beams emitted from the first laser light source 10 and the second laser light source 12 (S202).

[0083] As a result, similarly to the first embodiment, the peak level of the light receiving signal output from the light receiving element 30 can be made to approach the peak level of the light receiving signal when no tobacco stains are generated inside the optical pickup 4. As a result, it is possible to increase the peak levels of the FE signal generated by the FE signal generating unit 40, the TE signal generated by the TE signal generating unit 46, the RF signal generated by the RF signal generating unit 52, and the FS signal generated by the FS signal generating unit 54. After step S202, the process proceeds to step S108 described above.

[0084] [2-3. Effects] In this embodiment, when the disc determination unit 55 determines that the type of the optical disc 8 is BD and the peak level of the FS signal is less than the dirt determination threshold, the dirt determination unit 56A determines that dirt has occurred on the optical pickup 4 and controls the first laser light source 10 and the second laser light source 12 to increase the intensity of the laser light emitted from the first laser light source 10 and the second laser light source 12.

[0085] According to this, when the dirt determination unit 56A determines that dirt has occurred on the optical pickup 4, it controls the first laser light source 10 and the second laser light source 12 so as to increase the peak level of the light receiving signal from the light receiving element 30. This makes it possible to bring the peak level of the light receiving signal from the light receiving element 30 closer to the peak level of the light receiving signal when no tobacco dirt has occurred inside the optical pickup 4. As a result, for example, it is possible to increase the peak levels of the FE signal generated by the FE signal generation unit 40, the TE signal generated by the TE signal generation unit 46, the RF signal generated by the RF signal generation unit 52, and the FS signal generated by the FS signal generation unit 54, and it is possible to accurately record or reproduce information on the optical disc 8.

[0086] (Variations, etc.) As described above, the above-mentioned embodiments have been described as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are appropriately made. In addition, it is also possible to combine the components described in the above-mentioned embodiments to create new embodiments.

[0087] Therefore, other embodiments will be exemplified below.

[0088] In the above embodiments, cigarette stains have been described as an example of stains on the optical pickup 4, but the present invention is not limited to this, and may be, for example, dust stains or moisture stains caused by a humidifier.

[0089] In each of the above embodiments, each component may be implemented by dedicated hardware or by executing a software program suitable for each component. Each component may be implemented by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

[0090] Furthermore, some or all of the functions of the optical disc device 2 according to each of the above-described embodiments may be realized by a processor such as a CPU executing a program.

[0091] As described above, the embodiments have been described as examples of the technology in the present disclosure. For this purpose, the attached drawings and detailed description have been provided.

[0092] Therefore, among the components described in the attached drawings and detailed description, not only are there components essential for solving the problem, but there may also be components that are not essential for solving the problem in order to illustrate the above technology. Therefore, the fact that such non-essential components are described in the attached drawings or detailed description should not be interpreted as immediately indicating that such non-essential components are essential.

[0093] Furthermore, since the above-described embodiments are intended to illustrate the technology in the present disclosure, various modifications, substitutions, additions, omissions, and the like can be made within the scope of the claims or their equivalents. [Industrial Applicability]

[0094] The optical disc device of the present disclosure is applicable, for example, as a BD recorder or the like capable of recording and reproducing information on an optical disc. [Explanation of symbols]

[0095] 2,2A Optical disk device 4 Optical pickup 6,6A Control Unit 8. Optical Discs 8a Recording surface 10 First laser light source 12 Second laser light source 14 First beam splitter 15 Second beam splitter 16 Collimator lens 18 Reflector 20 Front Monitor 22 1 / 4 wave plate 24 Objective Lens 26 Lens Actuator 28 Cylindrical Lens 30 Photodetector 32 Light reception signal generation section 34 Received light signal gain adjustment section 36a, 36b, 36c, 36d Photodiodes 38 A / D conversion section 40 FE signal generator 42,48 AGC circuit 44 Focus control section 46 TE signal generator 50 Tracking control section 52 RF signal generation section 54 FS signal generation section 55 Disc Judgment Section 56,56A Dirt detection unit 57 LD type section

Claims

1. An optical disk device for recording or reproducing information on an optical disk by irradiating the optical disk with a laser beam, comprising: an optical pickup including a laser light source that emits a laser beam, an objective lens that converges the laser beam emitted from the laser light source onto the optical disc, and a light receiving element that receives reflected light from the optical disc and outputs a light receiving signal by photoelectrically converting the received reflected light; a light amount signal generating unit that generates a light amount signal indicating a light amount of reflected light from the optical disk based on the light receiving signal from the light receiving element; a dirt determining unit that determines that dirt has occurred on the optical pickup when the peak level of the light quantity signal is less than a first threshold value, and controls the light receiving element so as to increase the peak level of the light receiving signal from the light receiving element. Optical disk device.

2. The optical disk device further comprises: a focus error signal generating unit that generates a focus error signal based on the light receiving signal from the light receiving element; a first automatic gain controller that generates a normalized focus error signal that is a ratio of the focus error signal to the light quantity signal; the optical discs include a first optical disc and a second optical disc of different types; The laser light source is a first laser light source that emits a first laser light to be irradiated onto the first optical disk; a second laser light source that emits a second laser light to be irradiated onto the second optical disk; the optical disc device further includes a disc determination unit that, when the first laser light source emits a first laser beam, determines whether the type of the optical disc is the first optical disc based on a comparison between both amplitudes of the normalized focus error signal and a second threshold value; the dirt determination unit determines that dirt has occurred on the optical pickup when the type of the optical disk is determined to be the first optical disk by the disk determination unit and the peak level of the light quantity signal is less than the first threshold value; The light receiving element is a light reception signal generating unit that receives reflected light from the optical disk and generates the light reception signal by photoelectrically converting the received reflected light; a light receiving signal gain adjustment unit that amplifies the generated light receiving signal by a predetermined amplification factor; When the type of the optical disk is determined to be the first optical disk by the disk determination unit and the peak level of the light quantity signal is less than the first threshold value, the dirt determination unit determines that the optical pickup is dirty and controls the light reception signal gain adjustment unit to increase the predetermined amplification factor.

2. The optical disk device according to claim 1.

3. The optical disk device according to claim 1 or 2 is provided Recording and playback device.

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