JP4193030B2 - Optical head and recording / reproducing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording / reproducing apparatus for recording / reproducing various information on / from an optical recording medium, and an optical head provided in various optical devices such as the recording / reproducing apparatus. To Related.
[0002]
[Prior art]
An optical head that performs recording and reproduction with respect to an optical recording medium includes a light source that irradiates light to the optical recording medium, a plurality of light detection elements that detect reflected light beams from the optical recording medium, and detection from each light detection element And an I / V conversion circuit that amplifies the signal by I / V conversion.
When writing to a recordable optical recording medium such as a CD-R, DVD-R, or DVD-RW using the optical head, the emission power of the light source is such that a pit is formed on the optical recording medium during recording. The output power (write power) required for forming and the output power (bias power) not forming pits are controlled, and the output power (reading) required for detecting the pits of the optical recording medium during reproduction is controlled. Power). The write power is controlled based on the detection signal.
When high-speed writing is performed on the optical recording medium, the difference between the writing power and the reading power becomes large. In this case, if the I / V conversion circuit is configured so that the detection signal output from the I / V conversion circuit is not saturated at the write power, the I / V conversion circuit at the bias power and the read power It is difficult to perform servo control stably because the level of the detection signal decreases.
In order to prevent such an inconvenience, the I / V conversion circuit can obtain each detection signal at an appropriate level at the read power, and an RF signal for reproduction (RRF signal) at an appropriate level at the read power is supplied to an RRF terminal. The recording RF signal (WRF signal) at an appropriate level at the time of the writing power is output from the WRF terminal, and the WRF signal obtained from the WRF terminal is controlled by the OPC signal, that is, the power of the light source. It can be used as a signal for the purpose.
[0003]
[Problems to be solved by the invention]
However, if a new WRF terminal is added in addition to the RRF terminal, the number of terminals increases. Therefore, an existing PDIC (photodetector IC) package that constitutes the I / V conversion circuit may be used. However, this leads to an increase in the size of the package, which is disadvantageous in reducing the size of the optical pickup.
When recording on a DVD-R, two RRF terminals for differential transmission of the RRF signal must be provided in order to ensure the S / N ratio of the RRF signal during reproduction. In this case, it is necessary to add two terminals, the WRF terminal and the RRF terminal, which is further disadvantageous in reducing the size of the optical pickup.
The present invention has been made in view of such a situation, and the number of signal output terminals is increased even when the difference between the writing power and the reading power is increased in order to perform high-speed writing on the optical recording medium. This is advantageous for miniaturization. Light An object is to provide a head and a recording / reproducing apparatus.
[0004]
[Means for Solving the Problems]
Of the present invention Optical head To achieve the above purpose, By irradiating the optical recording medium with a light beam from a light source, pits are arranged on the optical recording medium, and the optical recording medium is irradiated with the light beam from the light source to reflect the reflected light beam on the optical recording medium. It is configured to detect pits of the optical recording medium by receiving light with a detection means, and the light detection means extends the light spot of the reflected light beam along the pit arrangement direction of the optical recording medium. And four detection elements that receive light in a region divided into four by a first dividing line and a second dividing line orthogonal to the first dividing line, and a detection signal input from each of the light receiving elements An optical head including an input I / V conversion circuit, wherein the I / V conversion circuit amplifies a sum of four detection signals output from each of the four light receiving elements with a first amplification factor. For playback Reproducing RF signal generating means for generating an F signal, generating and outputting a first reproducing RF signal and a second reproducing RF signal whose phases are inverted from each other from the reproducing RF signal, and the four light receiving elements Out of the first dividing lines, the two detection signals output from the two light receiving elements located on one side of the first dividing line are added, amplified with a second amplification factor, and output as a first signal. A signal generating means and two detection signals output from two light receiving elements located on the other side of the first dividing line among the four light receiving elements are added and amplified by the second amplification factor. Second signal generating means for outputting as a second signal, and the I / V conversion circuit has switching means having first and second output terminals, and the switching means During the reproduction operation of the recording medium, the reproduction signal output from the reproduction RF signal generation means First and second output RF signals are output from the first and second output terminals, respectively, and are output from the first and second signal generating means during recording operation of the optical recording medium. A signal is output from each of the first and second output terminals. It is characterized by that.
The recording / reproducing apparatus of the present invention also has a driving unit that holds and rotates the optical recording medium, and an optical recording medium that is rotated and driven by the driving unit. In addition to arranging pits, the optical recording medium is irradiated with the light beam from the light source, and the reflected light beam on the optical recording medium is received by the light detection means so that the pits of the optical recording medium are detected. An optical head configured, and the light detection means includes a first dividing line that extends a light spot of the reflected light beam along an arrangement direction of pits of the optical recording medium, and the first division. An I / V conversion circuit that includes four light receiving elements that receive light in a region divided into four by a second dividing line that is orthogonal to the line, and the optical head receives detection signals input from the four light receiving elements In the recording / reproducing apparatus provided, the I / V conversion circuit amplifies a sum of four detection signals output from each of the four light receiving elements by a first amplification factor to generate a reproduction RF signal, Reproduction RF signal generating means for generating and outputting a first reproduction RF signal and a second reproduction RF signal whose phases are inverted from each other from the reproduction RF signal, and among the four light receiving elements, A first signal generating means for adding two detection signals output from two light receiving elements located on one side of the dividing line, amplifying at a second amplification factor, and outputting the first signal; Of the four light receiving elements, two detection signals output from two light receiving elements located on the other side of the first dividing line are added and amplified by the second amplification factor to obtain a second signal. Second signal generating means for outputting , The I / V conversion circuit has switching means having first and second output terminals, The switching means outputs first and second reproduction RF signals output from the reproduction RF signal generation means from the first and second output terminals, respectively, during reproduction operation of the optical recording medium, and During recording operation of the recording medium, the first and second signals output from the first and second signal generating means are output from the first and second output terminals, respectively. It is characterized by that.
[0005]
Therefore, the present invention of According to the optical head and the recording / reproducing apparatus, the first and second reproduction RF signals are output from the differential signal generation means, the first signal is output from the first signal generation means, and the second signal generation means To output a second signal.
During the reproduction operation, the first and second reproduction RF signals are output, whereby information can be reproduced based on the first and second reproduction RF signals.
By outputting the first and second signals during the recording operation, the emission power of the light source is controlled based on the sum of the first and second signals, and the difference between the first and second signals is controlled. The land pre-pit can be read based on the signal.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, according to the present invention, Light An embodiment of a head and a recording / reproducing apparatus will be described in detail with reference to the drawings.
FIG. 3 shows the first embodiment of the present invention. Light It is a block diagram which shows the structure of the optical disk recording / reproducing apparatus incorporating a head. The optical disk recording / reproducing apparatus shown in FIG. 2 is an example of a recording / reproducing apparatus in which an optical head described below can be mounted.
[0007]
In FIG. 3, the recording / reproducing apparatus 101 includes a spindle motor 103 as driving means for rotationally driving an optical disk 102 as an optical recording medium, an optical head 104, and a feed motor 105 as driving means. Here, the spindle motor 103 is driven and controlled by the system controller 107 and the servo controller 109, and is rotated at a predetermined rotational speed.
In this embodiment, CD-R and DVD-R are used as the optical disk 102, and the optical head 104 is configured to perform recording and reproduction with respect to the CD-R and DVD-R. And
[0008]
The signal modulation / demodulation unit and the ECC block 108 perform signal modulation, demodulation, and addition of ECC (error correction code). The optical head 104 irradiates the signal recording surface of the rotating optical disk 102 with light according to the signal modulation and the instruction of the ECC block 108. Recording and reproduction with respect to the optical disc 102 are performed by such light irradiation.
The optical head 104 detects various light beams as will be described later based on the reflected light beam from the signal recording surface of the optical disc 102 and supplies a signal corresponding to each light beam to the preamplifier unit 120.
[0009]
The preamplifier unit 120 is a servo control signal based on a detection signal corresponding to each light beam, that is, a focus error signal, a tracking error signal, an OPC signal, an ATIP signal necessary for controlling the rotation of the optical disc during recording, and the like. Is configured to generate. The processing of these signals will be described later.
In accordance with the type of recording medium to be reproduced, predetermined processing such as demodulation and error correction processing based on these signals is performed by the servo control unit 109, signal modulation and ECC block 108, and the like.
Thereby, the demodulated recording signal is sent to the external computer 130 or the like via the interface 111 if it is for data storage of a computer, for example. Thus, the external computer 130 or the like can receive a signal recorded on the optical disc 102 as a reproduction signal.
The preamplifier unit 120 is a recording mode for recording information by forming pits on the optical disk 102, and a reproduction mode for reproducing information by detecting pits formed on the optical disk 102. A control signal SW indicating each is output to the I / V conversion circuit 20 (see FIGS. 1 and 2).
[0010]
For audio / visual use, the digital / analog conversion is performed by the D / A conversion unit of the D / A / A / D converter 112 and supplied to the audio / visual processing unit 113. Audio / video signal processing is performed by the audio / visual processing unit 113 and transmitted to an external imaging / projection device via the audio / visual signal input / output unit 114.
The optical head 104 is connected to a feed motor 105 for moving to a predetermined recording track on the optical disk 102, for example. Control of the spindle motor 103, control of the feed motor 105, and control of the focusing direction and tracking direction of the biaxial actuator that holds the objective lens of the optical head 104 are performed by the servo control unit 109, respectively.
That is, the servo control unit 109 controls the spindle motor 103 based on the ATIP signal, and controls the biaxial actuator based on the focus error signal and the tracking error signal.
The laser control unit 121 controls the laser light source in the optical head 104. In particular, in this example, the laser control unit 121 performs an operation of controlling the emission power of the laser light source during recording and during reproduction. In recording, the output power of the laser light source is controlled based on the R-OPC signal generated from the WRF signal.
[0011]
FIG. 4 is a block diagram showing the optical system of the optical head according to the first embodiment of the present invention.
In FIG. 4, an optical head 104 includes a laser light source 1, a grating element 2, a collimator lens 3, a beam splitter 4, an objective lens 5, a light detection means 6, a cylindrical lens 7, and an I / V conversion circuit 20 described later. These parts are mounted on a holder (not shown). In addition, the light detection means 6 and the I / V conversion circuit 20 are integrally configured in a single package.
Various known methods can be used for tracking error detection and focus error detection. In this example, the tracking error signal is detected by the DPP (Differential Push-Pull) method, and the focus error signal is detected. Is detected by the astigmatism (Astigma) method.
[0012]
In the optical head 104, the light beam emitted from the laser light source 1 passes through the grating element 2, is separated into one main beam and two side beams, passes through the collimator lens 3 and the beam splitter 4, and is supplied to the objective lens. The reflected light beam irradiated onto the optical disk 102 through 5 and reflected by the optical disk 102 is separated by the beam splitter 4 through the objective lens 5, and astigmatism is given by the cylindrical lens 7 to provide the light detection means 6. It is comprised so that it may be guided to.
[0013]
FIG. 5A is a plan view showing the configuration of the light detection means, and FIG. 5B is an explanatory view showing the position of each beam on the optical disc.
FIG. 5B shows a state in which one main beam B1 and two side beams B2 and B3 sandwiching the main beam B1 are irradiated on the DVD-R. The main beam is positioned on the groove G, and the side beams B2 and B3 are positioned on the land L to form a light spot.
As shown in FIG. 5A, the light detection means 6 includes a single substrate 62 and three detectors 6402 and 6404 that are linearly arranged on one surface of the substrate 62 with a space therebetween. , 6406.
The central detection unit 6402 receives the main beam B1, is formed in a rectangular shape that is divided into four in a square shape, and includes four light receiving elements 64A to 64D.
[0014]
In FIG. 5B, the light spot regions of the main beam B1 received by the light receiving elements 64A to 64D are respectively indicated by A to D. Regions A to D include a first dividing line L1 in which the light spot of the main beam B1 extends in the track direction of the optical disc, that is, in the direction in which pits are formed in the groove G or land L, and It is divided into four by a second dividing line L2 orthogonal to the first dividing line L1.
Therefore, the light receiving elements 64A and 64D are located on one side of the first dividing line L1, and the light receiving elements 64B and 64C are located on the other side of the first dividing line L1.
The detection unit 6404 located on one side of the central detection unit 6402 receives the side beam B2, has a rectangular shape divided into two, and receives light on the side close to the central detection unit 6402. It is composed of an element 64F and a light receiving element 64E on the side far from the central detection unit 6402.
The detection unit 6406 located on the other side of the central detection unit 6402 receives the other of the two side beams, has a rectangular shape divided into two, and is close to the central detection unit 6402 The light receiving element 64 </ b> G on the side and the light receiving element 64 </ b> H far from the center detection unit 6402 are configured.
5A and 5B, the positional relationship between the regions A to H is rotated by 90 degrees because the reflected light beam passes through the cylindrical lens 7.
The light receiving elements 64A to 64H are configured to output a current signal corresponding to the amount of received light as a detection signal. Hereinafter, detection signals output from the light receiving elements 64A to 64H are detected signals A to 64H. Let H be.
[0015]
FIG. 2 shows the first embodiment. Optical head It is a circuit diagram which shows the part which functions at the time of recording and reproduction | regeneration of CD-R among I / V conversion circuits.
The I / V conversion circuit 20 includes an I / V conversion unit 2002, an amplification unit 2004, an RRF signal generation unit 2006, a WRF signal generation unit 2008, and a first switching unit 2010.
The I / V conversion unit 2002 and the amplification unit 2004 are provided corresponding to the light receiving elements 64A to 64D, respectively, but only one is shown in FIG.
[0016]
Each I / V conversion means 2002 inputs each detection signal A to D output from the light receiving elements 64A to 64D via each input terminal T1 (four input terminals) to perform I / V conversion. The detection signals A to D as voltage signals obtained by doing so are input to each amplifying means 2004.
Each of the I / V conversion units 2002 is configured such that the detection signals output from the I / V conversion circuits 2002 are not saturated when the emission power of the laser light source 1 is the writing power. ing.
[0017]
Each amplifying unit 2004 receives each of the detection signals A to D inputted from each I / V converting unit 2002 and amplifies it with a predetermined amplification factor (corresponding to the first amplification factor in the claims). Thus, each output terminal T2 (actually four output terminals) is output.
The amplification factor of each amplification means 2004 is, for example, 1 or more, and when the output power of the laser light source 1 is the reading power and the bias power, the detection signals A to D are in focus control, tracking control, etc. Is set to a level necessary for normal servo control. Therefore, when the emission power of the laser light source 1 is the writing power, the levels of the detection signals A to D output from the amplification means 2004 are saturated.
[0018]
The RRF signal generation unit 2006 is configured to generate and output an RRF signal as a single reproduction RF signal by adding the detection signals A to D output from the amplification units 2004. Yes.
When the emission power of the laser light source 1 is the read power, the RRF signal generation unit 2006 makes the RRF signal at a level necessary for reading pits based on the RRF signal and reproducing information. It is configured.
[0019]
The WRF signal generation unit 2008 adds the detection signals A to D output from the I / V conversion units 2002, and amplifies the detection signals A to D with a predetermined amplification factor to generate a single recording RF signal. Is generated and output.
The amplification factor of the WRF signal generation unit 2008 is, for example, less than 1, and the power control of the laser light source 1 is normally performed by the WRF signal when the emission power of the laser light source 1 is the writing power. The level is set to a required level, that is, a level that does not saturate.
[0020]
The first switching means 2010 is based on the control signal SW input from the preamplifier unit 120, and the RRF signal output from the RRF signal generation means 2006 and the WRF output from the WRF signal generation means 2008. The signal is switched, and either the RRF signal or the WRF signal is output to the preamplifier 120 at the subsequent stage via the output terminal T3.
[0021]
FIG. 1 shows the first embodiment. Optical head It is a circuit diagram which shows the part which functions at the time of recording and reproduction | regeneration of DVD-R among I / V conversion circuits.
The I / V conversion circuit 20 includes, in addition to the I / V conversion unit 2002 and the amplification unit 2004, a differential signal generation unit 2012, a first addition amplification unit 2014, a second addition amplification unit 2016, The switching means 2018 is provided.
The functions of the I / V conversion means 2002 and the amplification means 2004 are the same as those described above.
[0022]
The differential signal generation unit 2012 amplifies the sum of the detection signals A to D output from the amplification units 2004 at a predetermined amplification factor to generate a single reproduction RF signal, and generates the single reproduction RF signal from the RF signal. A first reproduction RF signal RF + and a second reproduction RF signal RF−, whose phases are inverted from each other, are generated and output.
The amplification factor of the differential signal generation means 2012 is that the pits are determined based on the first reproduction RF signal RF + and the second reproduction RF signal RF− when the output power of the laser light source 1 is the read power. The level is set to a level necessary for reading and reproducing information.
[0023]
The first addition amplifying unit 2014 adds two detection signals A and D output from the two light receiving elements 64A and 64D located on one side of the first dividing line L1, and adds a predetermined amplification factor ( It is configured to amplify at a second amplification factor of claims and output as a first signal S1 (sum signal (A + D)).
The second addition amplification unit 2016 adds the two detection signals B and C output from the two light receiving elements 64B and 64C located on the other side of the first dividing line L1 to add the predetermined amplification factor. And output as the second signal S1 (sum signal (B + C)).
The amplification factors of the first and second addition amplification units 2014 and 2016 are smaller than the amplification factor of the amplification unit 2004, and when the emission power of the laser light source 1 is the read power, The first and second signals are set so as not to be saturated.
[0024]
Based on the control signal SW input from the preamplifier unit 120, the second switching means 2018 is configured to output the first and second reproduction RF signals RF + and RF− and the first and second signals S1. , S2 are switched and output to the preamplifier 120 at the subsequent stage via output terminals T4 and T5, respectively.
The output terminals T2, T3, T4, and T5 are provided in the package, and the output terminals T2, T3, T4, and T5 are connected to the preamplifier 120 by a wiring material (not shown). Therefore, signals output from the output terminals T2, T3, T4, and T5 are input to the preamplifier 120 through the wiring material.
[0025]
In the present embodiment, the I / V conversion unit 2002, the amplification unit 2004, and the differential signal generation unit 2012 constitute a reproduction RF signal generation unit as claimed in the claims.
The I / V conversion unit 2002 and the first addition amplification unit 2014 constitute a first signal generation unit as claimed in the claims. The I / V conversion unit 2002 and the second addition amplification unit 2016 are patented. The second signal generation means in the claims is configured.
The output terminals T4 and T5 constitute first and second output terminals as claimed in the claims.
[0026]
Next, the operation of the I / V conversion circuit 20 configured as described above will be described.
First, the case where the optical disk 102 is a CD-R will be described with reference to FIG.
In the reproduction mode, the detection signals A to D are I / V converted and amplified by the I / V conversion circuit 2002 and the amplifying means 2004, output to the preamplifier 120, and processed by the preamplifier 120 for tracking. An error signal and a focus error signal are generated and input to the servo control unit 109. The servo control unit 109 performs servo control based on these tracking error signal and focus error signal.
The detection signals A to D are generated as the RRF signal by the RRF signal generation unit 2006 and output to the preamplifier 120 through the first switching unit 2010, thereby reproducing information.
[0027]
In the recording mode, the detection signals A to D output from the amplifying unit 2004 are not saturated during the period in which the laser light source 1 is maintained at the bias power. Therefore, during the period, the detection signals A to D are processed by the preamplifier 120 to generate a tracking error signal and a focus error signal, and servo control is performed.
The address information recorded in the CD-R wobble in the recording mode is read with the sum signal (A + D) of the detection signals A and D by a subsequent circuit including the preamplifier 120 at the bias power. The ATIP signal obtained based on the difference between the detection signals B and C and the sum signal (B + C) is sampled.
Further, during the recording mode, during the period in which the laser light source 1 is maintained at the writing power, the WRF signal output from the WRF signal generation unit 2008 is input to the laser control unit 121 via the preamplifier 120. The The laser control unit 121 optimally controls the emission power of the laser light source 1 based on the WRF signal.
[0028]
Next, a case where the optical disk 102 is a DVD-R will be described with reference to FIG.
In the reproduction mode, as in the case of CD-R, a tracking error signal and a focus error signal are generated by the preamplifier 120 based on the detection signals A to D, and the servo control unit 109 performs the tracking error signal and the focus error signal. Servo control is performed based on
The first and second reproduction RF signals RF + and RF− output from the differential signal generation unit 2012 are output to the preamplifier 120 via the second switching unit 2010, thereby reproducing information. Done.
At this time, the first and second reproduction RF signals RF + and RF− are differentially transmitted from the I / V conversion circuit 20 to the preamplifier 120, so that the first and second reproduction RF signals RF + and RF− are not easily affected by noise. This is advantageous in improving the / N ratio.
[0029]
In the recording mode, the detection signals A to D output from the amplifying unit 2004 are not saturated during the period in which the laser light source 1 is maintained at the bias power. Therefore, during the period, the detection signals A to D are processed by the preamplifier 120 to generate a tracking error signal and a focus error signal, and servo control is performed.
The address information (disk address) recorded as land pre-pits (LPP) on the DVD-R land in the recording mode is read by the first and second additions by the subsequent circuit including the preamplifier 120. This is performed based on a difference signal (push-pull signal) between the first signal S1 and the second signal S2 output from each of the amplifying means 2014 and 2016 via the second switching means 2018.
[0030]
Further, during the recording mode, during the period in which the laser light source 1 is maintained at the writing power, the first signal S1 and the second signal S2 output from the first and second addition amplifying units 2014 and 2016, respectively. The signal S <b> 2 is input to the laser controller 121 through the preamplifier 120.
Therefore, the emission power of the laser light source 1 is optimally controlled by operating the laser control unit 121 based on the WRF signal obtained by adding the first signal S1 and the second signal S2.
[0031]
As described above, according to the present embodiment, the first signal S1 and the detection signals B and C as the sum signals of the first and second reproduction RF signals RF + and RF− and the detection signals A and D are detected. And the second and second reproduction RF signals RF + and RF− are output from the output terminals T4 and T5 of the I / V conversion circuit 20 for recording. In operation, the first and second signals S1 and S2 are output from the output terminals T4 and T5.
For this reason, even if the difference between the writing power and the reading power is increased to perform high-speed writing on the optical recording medium, the number of output terminals of the I / V conversion circuit 20 can be suppressed. By ,light This is advantageous in reducing the size of the pickup and the recording / reproducing apparatus.
In addition, by suppressing the number of output terminals of the I / V conversion circuit 20, it is possible to use an existing PDIC package constituting the I / V conversion circuit 20.
[0032]
In the recording mode, during the period in which the laser light source 1 is maintained at the writing power, the first and second signals S1 output from the first and second addition amplification units 2014 and 2016, respectively. , S2 is at a level that does not saturate, which is advantageous in stably controlling the emission power of the laser light source 1 by the laser controller 121.
[0033]
Further, unlike the CD-R, the reading of the address information of the DVD-R needs to be performed continuously during the recording mode, that is, both during the writing power and the bias power. This is because a land pre-pit recorded on a DVD-R requires an MTF band.
For example, when recording a DVD-R, as in the case of CD-R, the difference signal between the first signal S1 and the second signal S2 at the time of bias power is detected, that is, sampled to obtain the address information. Even if reading is performed, since the band at the time of reading becomes narrower than the band of the MTF, the land pre-pit cannot be detected correctly.
However, in the present embodiment, the first signal S1 and the second signal S2 output from each of the first and second addition amplifying units 2014 and 2016 are those when the laser light source 1 is at the writing power. However, since the level is not saturated, the land pre-pit can be reliably detected during the recording mode, that is, both at the writing power and the bias power. This is advantageous in stably performing the DVD-R recording operation.
[0034]
In this embodiment, the output terminal T3 of the I / V conversion circuit 20 and the output terminals T4 and T5 are provided independently. However, the output terminal T3 and any one of the output terminals T4 and T5 are provided. Can be shared by the same terminal. In this case, the number of output terminals can be reduced by one.
In the present embodiment, the light detection means 6 and the I / V conversion circuit 20 are described as being integrally provided in one package. However, the detection means 6 and the I / V conversion circuit 20 are different. It may be provided on the body.
In the present embodiment, the amplification unit 2004 and the first and second addition amplification units 2014 and 2016 are configured to amplify the signal. However, the I / V conversion unit 2002 and the differential signal generation are configured. A function of amplifying a signal may be provided for one or both of the means 2012.
In this embodiment, ,light Although it has been described that the pickup and the recording / reproducing apparatus perform recording and reproduction with respect to the DVD-R, it is of course possible to use the DVD-RW as the optical recording medium.
The present invention is also used when the output power of a light source that irradiates an optical recording medium with a light beam differs between recording and reproduction. Light It can be applied to a pickup and a recording / reproducing apparatus.
[0035]
【The invention's effect】
As described above, according to the present invention, an increase in the number of signal output terminals can be suppressed even when the difference between the write power and the read power is increased in order to perform high-speed writing on the optical recording medium. Advantageous for miniaturization Optical head and A recording / reproducing apparatus can be provided.
[Brief description of the drawings]
FIG. 1 shows the first embodiment. Optical head It is a circuit diagram which shows the part which functions at the time of recording and reproduction | regeneration of DVD-R among I / V conversion circuits.
FIG. 2 shows the first embodiment. Optical head It is a circuit diagram which shows the part which functions at the time of recording and reproduction | regeneration of CD-R among I / V conversion circuits.
FIG. 3 shows the first embodiment of the present invention. Light It is a block diagram which shows the structure of the optical disk recording / reproducing apparatus incorporating a head.
FIG. 4 is a configuration diagram showing an optical system of the optical head according to the first embodiment of the invention.
5A is a plan view showing the configuration of the light detection means, and FIG. 5B is an explanatory view showing the position of each beam on the optical disc.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Laser light source, 5 ... Objective lens, 6 ... Optical detection means, 102 ... Optical disk, 104 ... Optical head, 64A thru | or 64H ... Light receiving element, 20 ... I / V conversion circuit, 2004 ... Amplifying means, 2012... Differential signal generating means, 2014... First addition amplifying means, 2016... Second addition amplifying means, 2018.

Claims (7)

By irradiating the optical recording medium with a light beam from a light source, pits are arranged on the optical recording medium, and the optical recording medium is irradiated with the light beam from the light source to reflect the reflected light beam on the optical recording medium. It is configured to detect pits of the optical recording medium by receiving light with a detection means, and the light detection means extends the light spot of the reflected light beam along the pit arrangement direction of the optical recording medium. And four detection elements that receive light in a region divided into four by a first dividing line and a second dividing line orthogonal to the first dividing line, and a detection signal input from each of the light receiving elements An optical head having an input I / V conversion circuit,
The I / V conversion circuit is
A reproduction RF signal is generated by amplifying the sum of the four detection signals output from each of the four light receiving elements with a first amplification factor, and the phases are mutually inverted from the reproduction RF signal. A reproduction RF signal generating means for generating and outputting an RF signal and a second reproduction RF signal;
Of the four light receiving elements, two detection signals output from two light receiving elements located on one side of the first dividing line are added and amplified with a second amplification factor to obtain a first signal. First signal generating means for outputting;
Of the four light receiving elements, two detection signals output from two light receiving elements located on the other side of the first dividing line are added and amplified by the second amplification factor to obtain a second signal. Second signal generating means for outputting as
The I / V conversion circuit has switching means having first and second output terminals,
The switching means outputs first and second reproduction RF signals output from the reproduction RF signal generation means from the first and second output terminals, respectively, during reproduction operation of the optical recording medium, and The first and second signals output from the first and second signal generating means are output from the first and second output terminals during the recording operation of the recording medium.
An optical head characterized by that. Driving means for holding and rotating the optical recording medium;
The optical recording medium rotated by the driving means is irradiated with a light beam from a light source to arrange pits on the optical recording medium, and the optical recording medium is irradiated with the light beam from the light source to emit the light. An optical head configured to detect a pit of the optical recording medium by receiving a reflected light beam on the recording medium by a light detection means;
The light detecting means is configured to cause the light spot of the reflected light beam to pass through a first dividing line that extends along the pit arrangement direction of the optical recording medium and a second dividing line that is orthogonal to the first dividing line. Including four light receiving elements each receiving light in a region divided into four;
The optical head includes a recording / reproducing apparatus including an I / V conversion circuit that inputs detection signals input from the four light receiving elements.
The I / V conversion circuit is
A reproduction RF signal is generated by amplifying the sum of the four detection signals output from each of the four light receiving elements with a first amplification factor, and the phases are mutually inverted from the reproduction RF signal. A reproduction RF signal generating means for generating and outputting an RF signal and a second reproduction RF signal;
Of the four light receiving elements, two detection signals output from two light receiving elements located on one side of the first dividing line are added and amplified with a second amplification factor to obtain a first signal. First signal generating means for outputting;
Of the four light receiving elements, two detection signals output from two light receiving elements located on the other side of the first dividing line are added and amplified by the second amplification factor to obtain a second signal. Second signal generating means for outputting as
The I / V conversion circuit has switching means having first and second output terminals,
It said switching means, when reproduction operation of the optical recording medium and outputs each of the first output from the reproduction RF signal generator, a second RF signal reproduced from said first and second output terminals, before Symbol In the recording operation of the optical recording medium, the first and second signals output from the first and second signal generation means are configured to be output from the first and second output terminals, respectively.
And a recording / reproducing apparatus. The second amplification factor, wherein wherein said first at the time of recording operation of the optical recording medium is a first value the second signal is not saturated, which is output from the second signal generating means An optical head according to claim 1 or a recording / reproducing apparatus according to claim 2 . 3. The optical head according to claim 1, or the recording / reproducing apparatus according to claim 2, wherein the second amplification factor is smaller than the first amplification factor. When the pits are arranged on the optical recording medium, the emission power of the light source is controlled based on the recording WRF signal obtained by adding the first signal and the second signal. The optical head according to claim 1 or the recording / reproducing apparatus according to claim 2, wherein the optical head is configured as follows. The optical recording medium includes a groove in which the pits are arranged and a land in which land pre-pits indicating address information are arranged, and the pits are arranged when the pits are arranged in the grooves. 3. The optical head according to claim 1, wherein the address information is reproduced by detecting the land pre-pit based on a difference signal between the first signal and the second signal. The recording / reproducing apparatus as described . The light detection means and the I / V conversion circuit are integrally incorporated in a single package, and the I / V conversion circuit has switching means having first and second output terminals, The switching means outputs first and second reproduction RF signals output from the reproduction RF signal generation means from the first and second output terminals, respectively, during reproduction operation of the optical recording medium, and In the recording operation of the recording medium, the first and second signals output from the first and second signal generating means are configured to be output from the first and second output terminals, respectively. 3. The optical head according to claim 1, or the recording / reproducing apparatus according to claim 2, wherein the second output terminal is provided in the package.

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