WO2006003797A1

WO2006003797A1 - Optical pickup and information recorder/reproducer

Info

Publication number: WO2006003797A1
Application number: PCT/JP2005/011124
Authority: WO
Inventors: Naoharu Yanagawa; Fumihiko Sano
Original assignee: Pioneer Corporation
Priority date: 2004-06-30
Filing date: 2005-06-17
Publication date: 2006-01-12
Also published as: JP4340689B2; JPWO2006003797A1

Abstract

An information recorder/reproducer in which recording speed for an optical disc, e.g. a DVD-R, is enhanced while employing a simple arrangement and information can be recorded/reproduced surely. The optical pickup (PU) of an information recorder/reproducer (RP) is provided with a first light source outputting a light beam having a wavelength of 660 nm to comply with CD standards, and a second light source outputting a light beam having a wavelength of 780 nm to comply with DVD standards. When data recorded on an optical disc (DK) is reproduced, only one of the light sources complying with the standards of the optical disc (DK) is driven, while both first and second light sources are driven at the time of recording data. Furthermore, the optical pickup (PU) is provided with a wavelength filter (18) which is controlled such that only a light beam complying with the standards of the optical disc (DK) is received by a photodetector (17) at the time of recording data on the optical disc (DK).

Description

Specification

Optical pickup and information recording / reproducing apparatus

Technical field

The present invention relates to an optical pickup device used for recording and reproducing information on an information recording medium such as an optical disk.

Background art

[0002] Conventionally, an information recording / reproducing apparatus such as a compatible player (hereinafter simply referred to as “Compact Disc”) for recording and reproducing data on various optical discs having different standards such as DVD (Digital Versatile Disc) and CD (Compact Disc). Various information recording / reproducing devices are available! Speak. In this type of information recording / reproducing apparatus, it is desired to improve the recording speed of data on an optical disc such as a DVD-R from the viewpoint of improving user convenience and distinguishing from other products. .

[0003] However, in an optical disc such as a DVD-R or DVD-RW, when the total energy of the light beam irradiated per predetermined unit time exceeds a predetermined threshold, or the temperature on the optical disk increases. When it exceeds a certain value, it causes a dye discoloration or phase change, which causes various data to be recorded. Therefore, it is irradiated when the recording speed is improved and the relative speed of the optical disk with respect to the light beam increases. Data recording cannot be realized unless the amount of energy of the light beam to be increased is increased.

[0004] On the other hand, the light source used in this type of information recording / reproducing device has increased its heat dissipation as the outputable wattage has improved, and at present, a light source of about 150mW (milliwatt) has been realized from the viewpoint of heat dissipation measures, etc. It has only been done. For this reason, the theoretical maximum recording speed depends on the performance of the light source, and unless a new light source is developed, no further improvement in recording speed can be expected.

[0005] Therefore, conventionally, for example, when recording data on a CD-R, two light sources corresponding to each light beam having a wavelength of 780 nm and 650 ηm are simultaneously turned on, and tracking servo, focus using a light beam having a wavelength of 780 nm A proposal has been made to increase the utilization efficiency of a 65 Onm light beam used for data recording by performing servo (see Patent Document 1). Patent Document 1: Japanese Unexamined Patent Publication No. 2000-173084

Disclosure of the invention

Problems to be solved by the invention

[0006] Incidentally, in one apparatus described in Patent Document 1, a configuration is adopted in which two light beams having different wavelengths reflected by an optical disc are received by the same photodetector. However, when a powerful configuration is adopted, it is difficult to separate the received light beam forces unless the optical axes are accurately aligned, and crosstalk will occur between the two beams. When crosstalk occurs in this way, one light beam becomes noise relative to the other light beam, making it difficult to control data recording and tracking.

[0007] The present application has been made in view of the circumstances described above. As an example of the problem, the recording speed for an optical disc such as a DVD-R can be improved while reliably adopting a simple configuration. It is another object of the present invention to provide an optical pickup and an information recording / reproducing apparatus capable of recording and reproducing data.

Means for solving the problem

In order to solve the above-described problem, according to one aspect of the present application, the optical pickup according to claim 1 condenses the light beam output from the light source power on the information recording medium, and records the information. An optical pickup for receiving reflected light from a recording medium, the first light source outputting a first light beam having a first wavelength, and the second light having a second wavelength different from the first wavelength A second light source that outputs a beam; a light receiving unit that receives the reflected light reflected by the information recording medium and outputs a signal corresponding to the amount of received light; and the reflected light from the information recording medium to the light receiving unit A filter installed on the optical path for controlling the transmission of the incident second light beam, and controlling both the first light source and the second light source, and either one of the first light beam or the second light beam; Alternatively, light source control means for outputting both, When both the serial first and second light beam is output, characterized in that it comprises a filter control means for controlling said filter to limit transmission of the second beam.

[0009] Further, according to another aspect of the present application, the information recording / reproducing apparatus according to claim 9 condenses the light beam output from the light source power on the information recording medium, and from the information recording medium Reflection An information recording / reproducing apparatus including an optical pickup for receiving light, wherein the optical pickup includes a first light source that outputs a first light beam having a first wavelength, and a first light source that is different from the first wavelength. A second light source that outputs a second light beam having a wavelength of 2, a light receiving unit that receives the reflected light reflected by the information recording medium and outputs a signal corresponding to the amount of received light, and the information recording A filter that is installed on the optical path of the reflected light from the medium to the light receiving unit and controls transmission of the incident second light beam, controls both the first light source and the second light source, and controls the first light source. And the light source control means for outputting one or both of the second light beam and both the first and second light beams are output to control the filter to control the second beam. Filter control means for limiting transmission It is characterized by providing.

Brief Description of Drawings

FIG. 1 is a block diagram showing a configuration of an information recording / reproducing apparatus RP in an embodiment.

FIG. 2 is a conceptual diagram showing a focused spot on the optical disc DK and energy distribution on the focused spot in the same embodiment.

FIG. 3 is a diagram showing a configuration example when the wavelength filter 18 in the embodiment is configured using an inorganic EC material.

FIG. 4 is a diagram showing a configuration example when the wavelength filter 18 in the embodiment is configured using an organic EC material.

Explanation of symbols

[0011] RP---Information recording / reproducing apparatus

SP ... signal processor

C ', control unit

D ... Drive circuit

ρυ · · Optical pickup

β · · · Servo circuit

再生 ··· Playback part

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] "1Ί embodiment Hereinafter, the configuration and operation of the information recording / reproducing apparatus RP according to the present embodiment will be described with reference to FIG. 1 showing a schematic configuration of the information recording / reproducing apparatus RP according to the present embodiment. The information recording / reproducing apparatus RP according to the present embodiment is an application of the information recording / reproducing apparatus of the present application to a compatible player that records and reproduces data with respect to an optical disc DK compatible with both CD and DVD standards.

As shown in FIG. 1, the information recording / reproducing apparatus RP according to the present embodiment is roughly divided into a signal processing unit SP, a control unit C, a drive circuit D, an optical pickup PU, a servo circuit S, A reproduction unit P;

[0014] The signal processing unit SP has an input terminal. The signal processing unit SP performs signal processing on the data input via the terminal and outputs the processed data to the control unit C. The specific processing content performed in the signal processing unit SP is arbitrary. For example, after the input data is compressed by a compression method such as MPEG (Moving Picture Experts Group), the data is sent to the control unit C. You may make it output.

[0015] The control unit C is mainly configured by a CPU (Central Processing Unit) and controls each unit of the information recording / reproducing apparatus RP. For example, when data is recorded on the optical disc DK, the control unit C outputs a drive signal corresponding to the data input from the signal processing unit SP to the drive circuit D. Also, when reproducing data recorded on the optical disc DK, the control unit C outputs a predetermined drive signal to the drive circuit D regardless of whether or not data is input from the signal processing unit SP.

[0016] The drive circuit D is mainly configured as an amplifier circuit, and amplifies the drive signal input by the control unit C force and supplies the amplified drive signal to the optical pickup PU. The amplification factor in the drive circuit D is controlled by the control unit C. When data is recorded on the optical disc DK, the amount of energy that can cause phase change or dye discoloration in the optical pickup PU force optical disc DK (hereinafter, “ The amplification factor is controlled so that a light beam of “recording power” is output. On the other hand, when data recorded on the optical disc DK is played back, an optical beam with an energy amount (hereinafter referred to as “playback power”) is output from the optical pickup PU without any change in color change or the like in the optical disc DK. The amplification factor is controlled as described above.

The optical pickup PU includes, for example, a first light source 11, a second light source 12, and a first beam splitter 1 3, the second beam splitter 14, the actuator unit 15, the condenser lens 16, the photo detector 17, and the wavelength filter 18. Record and read data from DK.

The first light source 11 and the second light source 12 are both configured by laser diodes, and output light beams having different wavelengths based on the drive signal supplied to the drive circuit D force. In the present embodiment, the first light source 11 and the second light source 12 are used to realize data recording and reproduction corresponding to both DVD and CD standards, and the first light source 11 is a light having a wavelength of 660 nm. The second light source 12 outputs a light beam having a wavelength of 780 nm.

The light beams output from the first light source 11 and the second light source 12 are applied to the first and second beam splitters 13 and 14 disposed on the optical path of each light beam. The first beam splitter 13 and the second beam splitter 14 are constituted by, for example, dichroic mirrors, and reflect the light beams emitted from the corresponding light sources 11 and 12. When the first and second beam splitters 13 and 14 are configured by the Dyke mouth mirror, the first beam splitter 13 reflects 90% of the 660 nm light beam, transmits 10%, and the 78 Onm light beam. It is possible to adopt a dichroic mirror that transmits 100%, a dichroic mirror that reflects 90% of the 780 nm light beam and transmits 10% of the second beam splitter 14, and transmits 100% of the 660 nm light beam. desirable.

In this way, the light beams reflected by the first beam splitter 13 and the second beam splitter 14 are transmitted through a wave plate (not shown) provided in the actuator unit 15, and enter the actuator unit 15. It is incident on the installed objective lens and focused on the optical disc DK. The mechanism unit 15 for realizing the light beam condensing function is provided with a mechanism for moving the objective lens. The specific configuration of the actuator unit 15 is arbitrary.

Next, after the light beam irradiated on the optical disc DK is reflected on the optical disc DK, the first beam splitter 13 and the second beam are again passed through the objective lens of the actuator unit 15. The light enters the beam splitter 14, passes through the first beam splitter 13 and the second beam splitter 14, and enters the condenser lens 16. And incident on the condenser lens 16 The reflected light is condensed on the photodetector 17 by the condenser lens 16.

The photodetector 17 is constituted by, for example, a photodiode, receives the light beam emitted from the condenser lens 16, and outputs a signal corresponding to the amount of received light of the reflected light. Specifically, an RF signal corresponding to the amount of reflected light received is output to the control unit C, and signals necessary for tracking servo and focus servo are output to the servo circuit S.

[0023] When the RF signal is supplied from the photodetector 17 in this way, the control unit C (a) supplies the RF signal to the reproduction unit P during reproduction, and the data corresponding to the RF signal is supplied. (B) at the time of recording, for example, the address on the optical disc DK is acquired based on the RF signal, or the recording unit P is controlled so that the data is output to the outside via the output terminal. The output timing of the drive signal corresponding to the data to be recorded is determined.

The servo circuit S is constituted by an arithmetic circuit, calculates a servo amount related to tracking and focus based on a signal supplied from the photodetector 17, and outputs a control signal corresponding to the calculation result to the actuator unit 15. As a result, in the actuator unit 15, the position of the objective lens is changed based on the control signal fed back to the servo circuit S force, and tracking servo and focus servo are performed.

[0025] Note that a specific method for realizing the tracking servo and the focus servo is arbitrary. However, in the present embodiment, the following method is adopted to make the description specific. That is, the photodetector 17 is divided into four parts and a cylindrical lens is adopted as the condenser lens 16. For the focus servo 1, the astigmatism method is used to calculate the servo amount in the servo circuit S. For the tracking servo, the servo circuit S is calculated based on the amount of received light in each region. Then, the servo amount is calculated.

[0026] Here, in the information recording / reproducing apparatus RP having the powerful configuration, the optical disk DK is irradiated per unit time when attempting to improve the data recording speed with respect to the optical disk DK. The total amount of energy of the light beam irradiated to the optical disc DK is increased because the total amount of energy of the light beam exceeds a predetermined threshold or the temperature on the optical disc DK is required to be a certain value or more. It is necessary to make it. On the other hand, when playing back data recorded on the optical disc DK, There is no need to increase the amount of energy of the light beam irradiating Isk DK. Therefore, in the present embodiment, the control unit C performs the following control when data is recorded on and reproduced from the optical disc DK.

[0027] (1) During data recording

In this embodiment for improving the recording speed of data on the optical disc DK, the control unit C outputs a drive signal corresponding to the data to be recorded on the optical disc DK to the drive circuit D and the drive signal. Based on the above, the drive circuit D is controlled so that the light beam having the recording power is output from both the first light source 11 and the second light source 12. As a result, the first light source 11 and the second light source 12 emit light using the signal supplied also to the driving circuit D force, and the light beams output from the light sources 11 and 12, that is, light beams with wavelengths of 660 nm and 780 nm. Both are incident on the first beam splitter 13 and the second beam splitter 14, reflected by both the beam splitters 13 and 14, and applied to the objective lens of the actuator unit 15.

FIG. 2 shows the relationship between the focused spot appearing on the optical disc DK at this time and the energy distribution of the light beam in the focused spot. In the figure, each position on the focused spot is associated with the horizontal axis on the graph.

[0029] In this case, the radii r of the two focused spots with wavelengths of 660 nm and 780 nm are respectively

r = (kX λ) ΖΝΑ ... (Formula 1)

Will be shown. However, in (Equation 1), “E” indicates the wavelength, and “は” indicates the numerical aperture in the objective lens. In the case of this embodiment, since any light beam is incident on the same objective lens and is focused on the optical disc DK, the beam radius is determined substantially depending on the ratio of wavelengths. A 660 nm condensing spot is formed within the 780 nm condensing spot with a radius of about 80%.

[0030] Since the energy distribution for both focused spots follows a Gaussian distribution, both spots are in perfect agreement with the central point, and therefore, from the principle of superposition of light. The sum of the amount of energy at each point becomes the amount of energy of the light beam on the optical disc DK. For this reason, it is possible to increase the amount of energy of the light beam that can be irradiated onto the optical disc DK by setting both beams to be irradiated. [0031] However, when the optical disc DK is actually irradiated with both 780 nm and 660 nm light beams, spherical aberration is considered to occur due to the difference in focal length, resulting in energy loss. On the other hand, when both beams are irradiated, the energy can be used with a maximum efficiency of about 70 to 80% for the light beam of 780 nm.

[0032] It should be noted that in a dye-type optical disc DK such as a DVD-R, when the total amount of energy of the irradiated light beam exceeds a predetermined value, the dye discolors and information is recorded (photon mode). ) However, some information is recorded when the temperature on the recording surface exceeds a certain value (thermal recording). However, in any optical disc DK, the optical intensity of the light beam applied to the optical disc DK is changed. By improving the recording speed, it becomes possible to improve the recording speed.

[0033] In addition, when a configuration in which a light beam corresponding to two wavelengths is condensed on the optical disc DK is adopted as described above, and a CD light beam having a wavelength of 780 nm is irradiated onto the optical disc DK in accordance with the DVD standard, In this case, the light beam having a wavelength of 780 nm is a target to be recorded, so that not only the groove track but also the adjacent groove track is irradiated, and there is a possibility that phase change and dye discoloration may occur. Therefore, when the above configuration is adopted, the material used for the optical disc DK is appropriately selected, and information is not recorded when only the light beam having a wavelength of 780 nm is irradiated. It is necessary to do.

On the other hand, when a light beam is irradiated onto the optical disc DK from both the first light source 11 and the second light source 12, components having different wavelengths (660 η m and 780nm) will be mixed. For this reason, when the reflected light is incident on the photodetector 17, crosstalk occurs as described above, and it may be difficult to perform a normal recording operation. Therefore, in the present embodiment, a configuration in which the wavelength filter 18 is provided on the optical path of the reflected light from the optical disc DK is employed.

[0035] The wavelength filter 18 is made of, for example, an EC (Electro Chromic) material, and transmits only a light beam having a predetermined wavelength among incident light beams under the control of the control unit C. It has become. EC materials are materials that cause an electochromism phenomenon in which the absorption wavelength reversibly changes depending on the applied voltage, and there are two systems, organic and inorganic. Examples of inorganic EC materials include W03 (triacid) using electroabsorption reaction. Force sword EC (colored by reduction) such as Mo03 (molybdenum trioxide), and anodic EC (colored by oxidation) such as Phenolician benolet (KxFeyFez (CN) 6), Ni (OH) n In addition, organic EC materials include functional polymers such as polyphenazacillin used as organic EL (Electro Luminescent) materials.

[0036] Fig. 3 shows a configuration example of the wavelength filter 18 when inorganic EC is used, and Fig. 4 shows a configuration example of the wavelength filter 18 when organic EC is used.

First, in FIG. 3, reference numeral 101 denotes a substrate, which is made of a highly permeable base material such as Si02 (silicon dioxide). A transparent electrode 102 is formed on the substrate 101, and an EC layer 103 is formed on the transparent electrode 102 by forming a film by a sol-gel method, a pulling method, vapor deposition, or the like, followed by baking. Further, a transparent electrode 104 is further laminated on the EC layer 103, and as a result, the electoric chromic layer 103 is sandwiched between the transparent electrodes 102 and 104. The transparent electrodes 102 and 104 provided on the wavelength filter 18 are connected to the control unit C, respectively, and the control unit C generates a potential difference between the electrodes 102 and 104, so that the EC layer 103 The absorption wavelength will be changed reversibly.

[0038] When designing the wavelength filter 18, it is desirable to provide a steep absorption characteristic between 660 nm and 780 nm. For example, when Prussian blue is used as the EC layer 1803, it changes from blue to green with colorless potential by applying a potential difference of 0.2V, and further from blue to green with a potential difference of 1.0V. Therefore, the absorption wavelength can be adjusted to 78 Onm or 660 nm by changing the potential difference, and the filter characteristics required at a low voltage can be obtained by selecting an appropriate film pressure. Depending on the material used, a plurality of EC layers 1803 formed of different EC materials may be stacked to increase the light beam absorptance of each wavelength.

[0039] Next, when organic EC is used, the wavelength filter 18 is configured by bonding two transparent substrates 201 and 204 with a gap and filling the organic EC material 203 between the two substrates. Become. Transparent electrodes 202 and 205 are formed on opposite surfaces of the transparent substrates 201 and 204, respectively. The electrodes 202 and 205 are connected to the control unit C, and the control unit C has a potential difference between the electrodes 202 and 205. Reversible absorption wavelength in organic EC material 203 This will change the target.

Here, when the wavelength filter 18 is employed, a light beam reflected by the wavelength filter 18 is generated in addition to the light beam transmitted and absorbed. Therefore, if the wavelength filter 18 is installed at an angle with the incident axis of the light beam as a normal line, the light beam reflected on the wavelength filter 18 may stray on the optical axis. Therefore, it is necessary that the wavelength filter 18 be installed at a predetermined angle Θ with respect to the incident axis of the light beam so that no reflected light is generated on the incident in the filter 18.

[0041] If the wavelength filter 18 is installed closer to the actuator unit 15 than the first beam splitter 13 and the second beam splitter, the light beams output from both light sources absorb before the optical disk DK is irradiated. Alternatively, since reflection occurs, the wavelength filter must be installed on the photodetector 17 side of both beam splitters 13 and 14 without fail.

By configuring the wavelength filter 18 as described above, in the information recording / reproducing apparatus RP according to the present embodiment, for example, when information is recorded on a DVD-RW, the light beam reflected on the optical disc DK The light beam having a wavelength of 780 nm is absorbed and reflected by the wavelength filter 18, and only the light beam having a wavelength of 660 nm is transmitted through the wavelength filter 18 and received by the photodetector 17. Then, according to the light beam, signals necessary for the RF signal, tracking servo, and focus servo are obtained according to the amount of light received by the photodetector 18.

[0043] (2) Data re-cow.

On the other hand, when reproducing the information recorded on the optical disc DK, the control unit C causes only the light source corresponding to the standard of the optical disc DK to be reproduced to emit light. For example, if the optical disc that is to be played back is DK-powered and conforms to the SCD standard, the control unit supplies a drive signal to the first light source 11 to cause the first light source 11 to emit light, while being played back. When the optical disc DK is compatible with the DVD standard, a drive signal is supplied to the second light source 12 to cause the second light source 12 to emit light.

[0044] Further, how to control the wavelength filter 18 at the time of reproduction of the optical disk DK is arbitrary, and at the time of reproduction, the transmittance may be controlled to a maximum state, or the reproduction may be performed. The absorption wavelength may be changed according to the standard of the optical disc DK. Yes.

Note that, in the above-described embodiment, when there are two types of light sources, the type of the force light source described in the present invention is not limited to this. Specifically, in addition to a first light source for recording / reproducing on a DVD and a second light source for recording / reproducing on a CD, a light beam having a wavelength of 405 nm is used for recording / reproducing on a Blu-ray disc. The present invention can also be applied to an apparatus provided with a third light source capable of outputting. In this case, as a design of the light absorption characteristic of the wavelength filter 18, it is necessary to set the light absorption characteristic with respect to the wavelength of the laser light that has also generated at least two kinds of light source powers among the first to third light sources.

[0046] In addition, write-once recording media (dye-based discs) such as DVD-R and CD-R have wavelength dependence of recording performance depending on the dye used in the medium. Even if laser light having a wavelength is irradiated, there is a possibility that efficient writing cannot be performed. Specifically, laser light with a wavelength of 660 nm is appropriate for writing to DVD-R, and sufficient writing performance may not be obtained even when laser light with a wavelength of 780 nm is simultaneously irradiated. Therefore, when writing to such a recording medium, a single light source (laser light having a wavelength most suitable for the recording medium to be written is irradiated without simultaneously turning on the light sources. Recording may be performed using only a possible light source. In this case, it is preferable that the control unit C detects the type of the recording medium that it intends to write, and determines whether or not laser light irradiation is necessary for each of the plurality of light sources in accordance with the detection result.

[0047] Conversely, rewritable recording media (phase change discs) such as DVD-RW and DVD-RAM have low wavelength-dependent characteristics of recording performance and can be written by irradiating a sufficient amount of light. It is desirable to actively use. In this case, in order to secure the thermal energy necessary for writing to the recording medium, it is desirable to increase the distribution ratio of the driving current of the light source to the light source that has a short wavelength and can be irradiated with laser light.

In this way, the information recording / reproducing apparatus RP according to the present embodiment has the optical pickup PU that collects the light beam output from the light source on the optical disc DK and receives the reflected light from the optical disc DK. The optical pickup PU includes, for example, a first light source 11 that outputs an optical beam having a wavelength of 660 nm and a light beam having a wavelength of 780 nm, for example. A second light source 12 that outputs to the same optical path as the optical path of the output light beam, a photodetector 17 that receives the reflected light of the light beam reflected by the optical disc DK, and outputs a signal according to the amount of received light, It is installed on the optical path of the reflected light from the optical disc DK to the photodetector 17, and controls both the wavelength filter 18 that controls the transmission of the incident light beam, the first light source 11 and the second light source 12, and both the light sources 11 and When one or both of the light beams are output, and the light beams with the wavelengths of 660 nm and 780 nm are output together, the wavelength filter 18 is controlled to transmit the light beam with the wavelength of 780 nm. The control unit C to be restricted is provided!

[0049] With this configuration, the control unit C controls the wavelength filter 18 and is output from the first light source 11 in the environment where the light beams of both the first light source and the second light source are output. Only the light beam of the wavelength of the light passes through the wavelength filter 18. As a result, only the light beam having a wavelength of 660 nm is received by the photodetector 17. For this reason, for example, when recording data recorded on the optical disc DK, both the first light source 11 and the second light source 12 can also output a light beam, thereby increasing the total energy of the light beam irradiated on the optical disc DK. Even when both the light sources 11 and 12 are turned on, for example, only a light beam having a wavelength of 660 nm can be incident on the photodetector 17, so that the recording speed for an optical disc such as a DVD-R can be increased. In addition to improving this, it is possible to reliably record and play back data.

[0050] In the information recording apparatus RP according to the present embodiment, the wavelength filter 18 includes the electrochromic layer 103 or 203 that changes the wavelength of the light beam that can be transmitted according to the applied voltage value, and the electrochromic layer. The control unit C changes the voltage value applied to the transparent electrode to vary the transmission wavelength of the wavelength filter 18 to change the transmission wavelength of the wavelength filter 18 to 780 nm. It is configured to limit the transmission of a light beam with a wavelength of.

[0051] According to this configuration, it is possible to limit the transmission of a light beam having a wavelength of 780 nm only by controlling the voltage applied to the electoric layer 103 or 203, and thus adopting a simple configuration. It is possible to prevent crosstalk in the photodetector 17. [0052] Furthermore, in the information recording / reproducing apparatus RP according to the present embodiment, the control unit C controls, for example, only the first light source 11 to reproduce the data recorded on the optical disk DK, and has a wavelength of 660 nm. Is configured to output both light beams with wavelengths of 660 nm and 780 nm, for example, while controlling the first light source 11 and the second light source 12 when recording data on the optical disc DK. .

[0053] For this reason, it is possible to increase the total amount of energy of the light beam irradiated onto the optical disc DK for data recording while enabling reliable reproduction of the data recorded on the optical disc DK. It becomes.

[0054] Further, in the information recording / reproducing apparatus RP according to the present embodiment, the wavelength filter 18 is configured to be installed with a predetermined angle with respect to the optical path of the reflected light from the optical disc DK. ing. Therefore, stray light on the optical axis can be prevented even when a light beam reflected by the wavelength filter 18 is generated.

In the above embodiment, the wavelength filter 18 has been described as an example in which the wavelength filter 18 is made of an EC material V. However, the wavelength filter 18 is made of a material whose transmittance can be changed according to temperature, such as a cholesteric liquid crystal. 18 may be configured to transmit a light beam having one of the wavelengths by controlling the voltage supplied from the control unit C.

[0056] In the above embodiment, the device RP for recording and reproducing information with respect to the optical disc DK corresponding to both the CD and DVD standards has been described. For example, a Blu-ray disc and a CD or a Blu-ray disc and a DVD An apparatus for recording and reproducing information with respect to the optical disc DK corresponding to the above standard can be realized with the same configuration as described above.

Furthermore, in the present embodiment, the light beam output from the first light source 11 and the second light source 12 is directly irradiated to both the first beam splitter 13 and the second beam splitter 14. It has become. However, a diffraction grating is installed between the light source and the beam splitter, and the light beam output from the first light source 11 or the second light source 12 is divided into a main beam (0th order diffracted light) and a sub beam (± 1st order diffracted light). Thereafter, the first beam splitter 13 and the second beam splitter 14 may be irradiated. However, when adopting a powerful configuration, the photodetector 17 is provided with an area for receiving the main beam and the area is divided into four parts. In addition, it is necessary to provide a region for receiving the sub beam on the left and right sides of the region for receiving the main beam. In addition, the area for receiving the sub-beams can be further divided into left and right parts for tracking servo and focus servo using the sub-beams.

Furthermore, in the information recording / reproducing apparatus RP that is effective in the present embodiment, the force described in the example in which the control unit C and the drive circuit D are configured by a device such as a CPU separate from the optical pickup PU. It may be configured as a single unit!

Claims

The scope of the claims

[1] Light source power An optical pickup that focuses an output light beam on an information recording medium and receives reflected light from the information recording medium,

A first light source that outputs a first light beam having a first wavelength;

A second light source that outputs a second light beam having a second wavelength different from the first wavelength; receives the reflected light reflected by the information recording medium; and outputs a signal corresponding to the amount of received light A light receiver;

A filter installed on an optical path of the reflected light from the information recording medium to the light receiving unit, and controlling transmission of the incident second light beam;

Light source control means for controlling both the first light source and the second light source and outputting either one or both of the first and second light beams;

Filter control means for limiting the transmission of the second beam by controlling the filter when both the first and second light beams are output;

An optical pickup comprising:

[2] The filter is

A light-absorbing layer that varies the wavelength of the light beam that can be transmitted according to the applied voltage value;

An electrode for applying a voltage to the light absorbing layer,

2. The filter control means is characterized by limiting transmission of the second light beam by changing a transmission wavelength of the filter by changing a voltage value applied to the electrode. The optical pickup described in 1.

[3] The light source control means controls only the first light source to output the first light beam when reproducing the information recording medium, and outputs the first light beam when recording information on the information recording medium. 3. The optical pickup according to claim 1, wherein both of the second light sources are controlled to output both the first and second light beams.

4. The optical pickup according to claim 1, wherein the filter is installed with a predetermined angle with respect to the optical path of the reflected light.

[5] having detection means for determining the type of the information recording medium,

The light source control unit is configured to output the first light source and the second light source according to a detection result of the detection unit. 2. The optical pickup according to claim 1, wherein presence or absence of an output of the light beam from a light source is determined.

[6] When the information recording medium detected by the detecting means is a dye-type information recording medium, the light source control means can output a laser beam having a wavelength suitable for the information recording medium. 6. The optical pick-up according to claim 5, wherein the optical pick-up is output.

[7] having a detecting means for determining the type of the information recording medium,

2. The optical pickup according to claim 1, wherein the light source control unit changes an output ratio of the light beam from the first light source and the second light source according to a detection result of the detection unit.

[8] When the information recording medium detected by the detecting means is a phase change information recording medium, the laser beam having the light source power capable of outputting a laser beam having a short wavelength out of the first light source and the second light source. 2. The optical pickup according to claim 1, wherein an output ratio is made larger than an output ratio of the laser light from another light source.

[9] Light source power An information recording / reproducing apparatus including an optical pickup that focuses an output light beam on an information recording medium and receives reflected light from the information recording medium,

The optical pickup is

A first light source that outputs a first light beam having a first wavelength;

An information recording / reproducing apparatus comprising: