JPWO2006011314A1 - Optical pickup device and information recording/reproducing device - Google Patents

Abstract

Even when the recording speed of data on the optical disc is improved, the S/N ratio at the time of reproducing the optical disc is ensured without complicating the circuit configuration. A wavelength filter 18 is provided in the optical pickup PU of the information recording/reproducing device RP. The wavelength filter 18 is made of, for example, an EC (Electrochromic) material, and changes the light absorption characteristic according to the voltage supplied from the control unit C. By utilizing the function of the wavelength filter 18, the transmittance of the reflected light from the optical disk DK is maximized when the data recorded on the optical disk DK is reproduced, and the transmittance of the reflected light is recorded when the data is recorded on the optical disk DK. Then, the energy amount of the reflected light with which the photodetector 17 is irradiated is reduced.

Description

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

  Conventionally, in an information recording/reproducing apparatus that records and reproduces data on an optical disc such as a CD (Compact Disc) or a DVD (Digital Versatile Disc), the convenience of the user is improved or the product is differentiated from other products. From the viewpoint, the recording speed of data on an optical disc such as a DVD-R is being improved.

  Here, in an optical disc such as a DVD-R or a DVD-RW, when the total amount of energy of a light beam irradiated per unit time exceeds a predetermined threshold value, or the temperature on the optical disc exceeds a certain value. If the optical disc rotation speed is increased to increase the recording speed, the energy of the light beam emitted to the optical disc changes because the dye changes color or changes its phase and various data is recorded. Data cannot be recorded unless the amount is increased. Therefore, in order to improve the recording speed, it is essential to increase the energy amount of the light beam output from the light source.

  On the other hand, when the energy amount of the light beam during recording is improved in this way, the difference between the amount of reflected light received by the photodetector during playback and the amount of light received by the photodetector during recording increases, and the reflected light at the photodetector increases. May not be received normally. For example, when a photodetector is designed so that an RF signal can be accurately obtained by the reflected light at the time of reproduction, if the energy amount of the reflected light at the time of recording increases and exceeds the dynamic range of the photodetector, the photodetector receives the light normally. It becomes impossible to do it.

  Therefore, in the conventional information recording/reproducing apparatus, the amount of light received is adjusted when the recording speed is improved by adopting the following method.

< Method 1 >
A filter is provided on the optical path of the reflected light that enters the photodetector from the optical disc to reduce the amount of energy of the reflected light that enters the photodetector.

< Method 2 >
A photodetector is configured using an OEIC that integrates various circuits such as a light receiving element and an amplifier circuit, and the amplification factor of the amplifier circuit is switched at the time of recording or reproducing data on an optical disc, and the reflected light at the time of recording and reproduction is changed. Can receive light.

  However, when the above-mentioned conventional method 1 is adopted, it becomes difficult to secure the S/N ratio at the time of reproducing the data recorded on the optical disc. That is, when a filter is provided on the optical path of the reflected light, the amount of energy of the reflected light that should be reduced only during recording is reduced during reproduction, and it becomes difficult to secure the level of the RF signal. is there.

  On the other hand, according to the above method 2, since the amount of energy of the reflected light is not reduced before receiving the light, it is possible to secure the level of the RF signal at the time of reproduction, but on the other hand, the configuration of the photo detector becomes complicated, In addition, the control method itself of the device becomes complicated.

  The present application has been made in view of the circumstances described above, and as an example of the problem, even if the data recording speed on the optical disc is improved, the optical disc can be formed without complicating the circuit configuration. It is an object of the present invention to provide an optical pickup device and an information recording/reproducing device capable of ensuring an S/N ratio during reproduction.

  In order to solve the above-mentioned problems, in one aspect of the present application, an optical pickup device according to claim 1 irradiates a recording surface of an information recording medium with a light beam output from a light source, and reflects from the recording surface. An optical pickup device for receiving light, comprising a light source control means for changing the light intensity of the light beam according to recording and reproduction on the information recording medium, and a signal for receiving the reflected light and corresponding to the received light amount. A filter for controlling the amount of transmission of the incident reflected light, which is arranged on the optical path of the reflected light, and a filter for controlling the filter according to the light intensity of the light beam. And a filter control means for controlling the amount of transmitted light.

  According to another aspect of the present application, the information recording/reproducing apparatus according to claim 5 irradiates a recording surface of an information recording medium with a light beam output from a light source and receives reflected light from the recording surface. An optical recording/reproducing apparatus including an optical pickup device for reproducing the light intensity of the light beam according to recording and reproducing on the information recording medium, and the reflected light. Light receiving means for receiving a light and outputting a signal according to the amount of received light, a filter arranged in the optical path of the reflected light for controlling the amount of transmission of the reflected light that is incident, and a light intensity according to the light intensity of the light beam. And a filter control unit that controls the filter to control the transmission amount of the reflected light.

3 is a block diagram showing a configuration of an information recording/reproducing device RP in the embodiment. FIG. It is a figure which shows the structural example in case the wavelength filter 18 in the same embodiment is comprised using an inorganic EC material. It is a figure which shows the structural example at the time of comprising the wavelength filter 18 in the same embodiment using an organic EC material.

Explanation of symbols

RP... Information recording/reproducing apparatus SP... Signal processing section C... Control section D... Driving circuit PU... Optical pickup S... Servo circuit P... Reproducing section

[1] Embodiment (1) Overall configuration and outline of operation Hereinafter, with reference to FIG. 1 showing a schematic configuration of an information recording/reproducing apparatus RP according to the present embodiment, an overall configuration of the information recording/reproducing apparatus RP according to the present embodiment. Also, the operation outline will be described. 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 on an optical disc DK compatible with both the CD and DVD standards.

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

  The signal processing unit SP has an input terminal, performs signal processing on data input from the outside through this terminal, and outputs the data to the control unit C. The specific processing contents performed in the signal processing unit SP are arbitrary, and for example, after the input data is compressed by a compression method such as MPEG (Moving Picture Experts Group), the data is output to the control unit C. It may be done.

  The control unit C mainly includes a CPU (Central Processing Unit) and controls each unit of the information recording/reproducing device RP. For example, when recording data 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. When reproducing the data recorded on the optical disc DK, the control unit C outputs a predetermined drive signal to the drive circuit D regardless of the presence or absence of data input from the signal processing unit SP.

  The drive circuit D is mainly configured as an amplifier circuit, amplifies the drive signal input from the control unit C, and then 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, and when recording data on the optical disc DK, the amount of energy capable of causing a phase change or pigment discoloration from the optical pickup PU to the optical disc DK (hereinafter, referred to as “ The amplification factor is controlled so that a light beam of "recording power" is output. On the other hand, when reproducing the data recorded on the optical disk DK, the optical pickup PU outputs a light beam having an energy amount (hereinafter, referred to as “reproduction power”) that does not cause a change such as pigment discoloration in the optical disk DK. The amplification factor is controlled.

  The optical pickup PU is used for irradiating the optical disc DK with a light beam based on a control signal supplied from the drive circuit D to record and read data on the optical disc DK. In order to realize such a function, in the present embodiment, the optical pickup PU includes, for example, a first light source 11, a second light source 12, an optical unit 2, a condenser lens 16, a photodetector 17, and a wavelength filter 18. ,have.

  The first light source 11 and the second light source 12 are both configured by laser diodes, and output light beams of different wavelengths based on the drive signal supplied from the drive circuit D. In the present embodiment, the first light source 11 and the second light source 12 respectively emit light having a wavelength of 660 nm so that the first light source 11 can record and reproduce data compatible with both DVD and CD recording standards. The second light source 12 outputs a light beam having a wavelength of 780 nm. These light sources 11 and 12 are used properly according to the type of the optical disc DK that is the target of data reproduction and recording, and when the optical disc DK is a DVD, only the first light source 11 is used.

  The optical unit 2 has a function of condensing the light beams output from the first light source 11 and the second light source 12 onto the optical disc DK. For example, the first beam splitter 13, the second beam splitter 14, and the actuator unit. 15 and. The first beam splitter 13 and the second beam splitter 14 that form the optical unit 2 are configured by, for example, dichroic mirrors, and the actuator unit 15 includes an objective lens (not shown). Further, the actuator unit 15 has a movable mechanism of the objective lens, and changes the position of the objective lens based on the control signal supplied from the servo circuit S to realize tracking servo and focus servo. When the first and second beam splitters 13 and 14 are composed of dichroic mirrors, the first beam splitter 13 reflects 90% of the 660 nm light beam and transmits 10% and the 780 nm light beam of 100%. It is desirable to adopt a dichroic mirror for the second beam splitter 14 that reflects 90% of the 780 nm light beam by 10% and transmits 100% of the 660 nm light beam by 100%.

  The condensing lens 16 condenses the reflected light, which is transmitted through the objective lens of the actuator unit 15 and the first and second beam splitters 13 and 14 and is incident on the photodetector 17.

  The photodetector 17 is composed of, for example, a photodiode, receives the light beam emitted from the condenser lens 16, outputs an RF signal to the control unit C, and outputs a signal necessary for tracking servo and focus servo to a servo circuit. Output to S.

  Note that a specific method for realizing the tracking servo and the focus servo is arbitrary. For example, the photodetector 17 may be divided into four parts, a cylindrical lens may be used as the condenser lens 16, and the servo amount may be calculated in the servo circuit S for the focus servo by using the astigmatism method. Also, regarding the tracking servo, the servo amount may be calculated in the servo circuit S based on the received light amount in each of the divided regions of the photodetector 17.

  The wavelength filter 18 has a configuration capable of changing the absorption wavelength and the transmittance of the incident light beam under the control of the controller C. Generally, in the information recording/reproducing apparatus RP, when an attempt is made to improve the data recording speed with respect to the optical disc DK, the total amount of energy of the light beam with which the optical disc DK is irradiated per unit time exceeds a predetermined threshold value, or the optical disc DK Since it is necessary for the temperature above to reach a certain value or higher, it is necessary to increase the energy amount of the light beam with which the optical disc DK is irradiated. On the other hand, when the energy amount (recording power) of the light beam at the time of recording data on the optical disc DK is increased, the light amount of the reflected light received by the photodetector 17 when the optical beam having the reproducing power is applied to the optical detector DK, When a light beam of recording power is applied to the optical disc DK, the difference in the amount of reflected light received by the photodetector 17 becomes large, and the photodetector 17 may not be able to receive both reflected lights normally. In view of this, in the present embodiment, the amount of reflected light transmitted when the optical disc DK is irradiated with a light beam of recording power is reduced by the wavelength filter 18, and the energy of the reflected light that reaches the photodetector 17 is reduced. It uses a configuration that reduces the amount. The specific configuration of the wavelength filter 18 will be described in detail in the next section.

  In the information recording/reproducing device RP having the above-mentioned configuration, the light beam output from the first light source 11 or the second light source 12 is reflected by the first and second beam splitters 13 and 14, and the actuator unit 15 is operated. The light enters the objective lens and is condensed on the optical disc DK. In this way, when the light beam is focused on the optical disc DK, the light beam is reflected by the optical disc DK, and then again through the objective lens of the actuator unit 15 and the first beam splitter 13 and the second beam splitter 13. The light enters the beam splitter 14, passes through the first beam splitter 13 and the second beam splitter 14, and passes through the wavelength filter 18. At this time, the amount of energy of the reflected light from the optical disc DK is controlled by the wavelength filter 18, and then enters the condenser lens 16, and is condensed on the photodetector 17 by the condenser lens 16. As a result, the RF signal is output from the photodetector 17 to the control unit C, and the signals necessary for the tracking servo and the focus servo are output to the servo circuit S.

  Further, when the RF signal is supplied from the photo detector 17, the control unit C outputs the data corresponding to the RF signal to the reproducing unit P when reproducing the data recorded on the optical disc DK, and the reproducing unit P The data is output to the outside. On the other hand, when recording data on the optical disc DK, the control unit C determines, for example, the address acquisition on the optical disc DK or the output timing of the drive signal corresponding to the data to be recorded based on the RF signal. Further, the servo circuit S calculates the servo amount based on the signal supplied from the photodetector 17, and outputs a control signal corresponding to the calculation result to the actuator unit 15. As a result, the arrangement position of the objective lens in the actuator section 15 is changed, and tracking servo and focus servo are realized.

(2) Specific Structure and Control of Wavelength Filter 18 Next, a specific structure of the wavelength filter 18 and its control will be described.

  First, in the present embodiment, the wavelength filter 18 is made of, for example, a material called an EC (Electrochromic) material. This EC material is a material that causes an electrochromic phenomenon in which the absorption wavelength reversibly changes with an applied voltage, and changes from a transparent state to a state where each color is exhibited by absorbing only a light beam of a predetermined frequency by the applied voltage. It has characteristics. As the EC material, there are two systems, an inorganic system and an organic system. As the inorganic EC material, for example, a cathode EC such as WO3 (tungsten trioxide) or MoO3 (molybdenum trioxide) that utilizes an electric absorption reaction is used. (Colored by reduction), anodic EC (colored by oxidation) such as Prussian blue (KxFeyFez(CN)6), Ni(OH)n, etc., and used as an organic EC (Electro Luminescent) material There are functional polymers such as polyphenazacillin.

  FIG. 2 shows a configuration example of the wavelength filter 18 when using the inorganic EC, and FIG. 3 shows a configuration example of the wavelength filter 18 when using the organic EC.

  First, in FIG. 2, reference numeral 101 denotes a substrate, which is made of a highly permeable base material such as SiO 2 (silicon oxide). 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 method such as a sol-gel method, a pulling method, or vapor deposition, and then firing the film. A transparent electrode 104 is further laminated on the EC layer 103, and as a result, the electrochromic layer 103 is sandwiched between the transparent electrodes 102 and 104. Both 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 to absorb light in the EC layer 103. The characteristics will be reversibly changed.

  Since the absorbance of the EC material differs depending on the material used, when specifically designing the wavelength filter 18, the wavelength filter 18 is made to pass through based on the energy amount of the reflected light at the time of recording and the dynamic range of the photodetector 17. It is necessary to calculate the amount of energy of reflected light and change the thickness of the EC layer 103. For example, in the case of the present embodiment, since the light beams having the wavelengths of 660 nm and 780 nm are used, the reflected light of any wavelength is absorbed at the time of recording data and is received by the photodetector 17 at the time of recording data. It is necessary to reduce the amount of reflected light energy. Therefore, for example, when PB (Prussian blue) is used as the EC layer 103, coloring from colorless to blue occurs when 0.2 V is applied, and by providing an appropriate film thickness, filter characteristics required at low voltage Can be obtained.

  Next, when the organic EC is used, the wavelength filter 18 is configured by bonding the two transparent substrates 201 and 204 with a gap and filling the organic EC material 203 between the two substrates. Transparent electrodes 202 and 205 are formed on the facing surfaces of the transparent substrates 201 and 204, respectively. The electrodes 202 and 205 are connected to a control unit C, and the control unit C applies a potential difference between the electrodes 202 and 205. By causing it, the absorption wavelength in the organic EC material 203 is reversibly changed. In this case as well, the thickness of the EC layer 203, the applied voltage value, and the like need to be appropriately designed, as in the case of using the inorganic EC material.

  Here, when this wavelength filter 18 is adopted, in addition to the light beam that is transmitted and absorbed, a light beam that is reflected by the wavelength filter 18 is also generated. Therefore, if the wavelength filter 18 is installed at an angle with the incident axis of the light beam as the normal line, the light beam reflected on the wavelength filter 18 may stray on the optical axis. Therefore, the wavelength filter 18 needs to be installed at a predetermined angle θ with respect to the incident axis of the light beam so that the filter 18 does not generate reflected light on the optical axis.

  Further, if the wavelength filter 18 is installed closer to the actuator unit 15 side than the first beam splitter 13 and the second beam splitter, the light beams output from both light sources are absorbed or reflected before being irradiated on the optical disc DK. Therefore, the wavelength filter 18 needs to be installed closer to the photodetector 17 than the beam splitters 13 and 14.

  In the information recording/reproducing apparatus RP according to the present embodiment in which the wavelength filter 18 is configured as described above, the control unit C controls the voltage applied to the wavelength filter 18 to change the light absorption characteristic of the wavelength filter 18. It will be. Specifically, when reproducing the data recorded on the optical disk DK, the control unit C controls the voltage applied to the wavelength filter 18 to maximize the amount of reflected light transmitted through the wavelength filter 18 (that is, the transparent state). By maintaining the state), the amount of energy of reflected light reduced in the wavelength filter 18 is suppressed to the minimum. As a result, it is possible to minimize the decrease in the amount of energy of the reflected light that is incident on the photodetector 17 during reproduction of the data recorded on the optical disc DK, and to secure the level of the RF signal during reproduction.

  On the other hand, at the time of recording data on the optical disk DK, that is, while irradiating the light beam with the recording power, the control unit C controls the voltage applied to the wavelength filter 18 to generate reflected light of a predetermined frequency. The wavelength filter 18 is maintained in a state where it absorbs light and the transmittance of reflected light is reduced. At this time, the control unit C determines whether the optical disk DK as the data recording target complies with the CD standard or the DVD standard, and the voltage value to be applied to the wavelength filter 18. And the absorption wavelength in the wavelength filter 18 is changed. As a result, the reflected light on the optical disc DK has its energy amount reduced by the wavelength filter 18 and is incident on the photodetector 17, and in the state where the light beam of the recording power is output from any one of the light sources 11 and 12. Also, the energy amount of the reflected light received by the photodetector 17 is reduced to the same level as the reproduction power.

  In this way, in the information recording/reproducing apparatus RP according to the present embodiment, the optical pickup PU irradiates the recording surface of the optical disc DK with the light beam output from the first light source 11 or the second light source 12, and also the recording surface. An optical pickup PU for receiving the reflected light from the optical disc DK, which receives the reflected light from the optical disc DK and a control unit C and a drive circuit D which change the light intensity of the light beam according to recording and reproduction on the optical disc DK. And a photodetector 17 that outputs a signal according to the amount of received light, a wavelength filter 18 that is disposed in the optical path of reflected light and that controls the amount of transmitted reflected light that is incident, and the light intensity of the light beam that is irradiated on the recording surface. The control unit C controls the wavelength filter 18 according to the above to control the transmission amount of the reflected light.

  With this configuration, according to the light intensity of the light beam with which the recording surface of the optical disc DK is irradiated, for example, in the state where the light beam with the recording power is applied to the recording surface of the optical disc DK, the reflected light from the optical disc DK After the energy amount is reduced by the wavelength filter 18, the photodetector 17 receives the light. Therefore, the data recording speed on the optical disc DK is improved, and even when the amount of energy of the light beam applied to the optical disc DK is increased, the circuit configuration is not complicated and the photodetector 17 is appropriately reflected. It becomes possible to receive light.

  Further, in this configuration, since the transmission amount of the reflected light in the wavelength filter 18 can be changed based on the voltage applied from the control unit C, the transmission amount of the reflected light in the wavelength filter 18 can be reduced when the data is recorded on the optical disc DK. At the same time, at the time of reproducing the data recorded on the optical disk DK, the transmission amount of the reflected light from the optical disk DK is maximized to secure the level of the RF signal at the time of reproducing the data. It is also possible to secure.

  Further, in the information recording device RP according to the present embodiment, the wavelength filter 18 includes the electrochromic layer 103 or 203 whose absorption wavelength is variable depending on the applied voltage value, and the transparent electrode which applies a voltage to the electrochromic layer 103 or 203. In addition to the above, the control unit C changes the voltage value applied to the transparent electrode to change the absorption wavelength of the wavelength filter 18, thereby reducing the transmission amount of the reflected light from the optical disk DK. ing.

  With this configuration, it is possible to limit the transmission amount of the reflected light from the optical disk DK only by controlling the applied voltage to the electro-chemical layer 103 or 203, and thus the proper configuration of the photodetector 17 can be achieved while adopting a simple configuration. It is possible to realize light reception.

  Furthermore, in the information recording/reproducing apparatus RP according to the present embodiment, the control unit C reduces the transmission amount when the light intensity of the light beam irradiated on the recording surface of the optical disc DK is increased, and the light of the light beam is emitted. When the strength becomes weak, the amount of transmission increases.

  Therefore, the transmission amount of the reflected light in the wavelength filter 18 is controlled when recording and reproducing the data on the optical disc DK, and the design of the photodetector 17 can be facilitated. That is, even if the dynamic range of the photodetector 17 is narrow, the energy amount of the reflected light can be controlled by the wavelength filter 18, so that even when the optical beam is applied to the optical disc DK with the recording power. It is possible to suppress the amount of energy of the reflected light received by the photodetector 17 to about the reproduction power and realize reliable light reception.

  Further, in the information recording/reproducing device RP according to the present embodiment, the wavelength filter 18 is configured to be installed at a predetermined angle with respect to the optical path of the reflected light from the optical disc DK. Even if a light beam reflected at 18 is generated, it is possible to prevent stray light on the optical axis.

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

  Further, in the above embodiment, the device RP which records and reproduces information on the optical disc DK compatible with both the CD and DVD standards has been described. However, for example, it corresponds to the standard of Blu-ray disc and CD or the standard of Blu-ray disc and DVD. An apparatus for recording and reproducing information on the optical disc DK can be realized by the same configuration as above.

  Furthermore, in the present embodiment, the light beams output from the first light source 11 and the second light source 12 are directly applied to both the first beam splitter 13 and the second beam splitter 14. 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). After that, the irradiation may be performed on the first beam splitter 13 and the second beam splitter 14. However, when such a configuration is adopted, the photodetector 17 is provided with a region for receiving the main beam, and the region is divided into four parts, and the sub-beams are provided on the left and right of the region for receiving the main beam. It is necessary to provide a region for receiving light. Further, the area for receiving the sub beam is further divided into left and right halves, so that tracking servo and focus servo using the sub beam can be performed.

  Further, in the information recording/reproducing apparatus RP according to the present embodiment, an example in which the control unit C and the driving circuit D are configured by a device such as a CPU which is separate from the optical pickup PU has been described, but these are integrated with the optical pickup PU. It may be configured in a physical manner.

[0002]
[0006] < Method 1 >
A filter is provided on the optical path of the reflected light that enters the photodetector from the optical disc to reduce the amount of energy of the reflected light that enters the photodetector.
[0007] < Method 2 >
A photodetector is configured using an OEIC that integrates various circuits such as a light receiving element and an amplifier circuit, and the amplification factor of the amplifier circuit is switched at the time of recording or reproducing data on an optical disc, and the reflected light at the time of recording and reproduction is changed. Can receive light.
DISCLOSURE OF THE INVENTION
[Problems to be Solved by the Invention]
However, when the above-mentioned conventional method 1 is adopted, it becomes difficult to secure the S/N ratio at the time of reproducing the data recorded on the optical disc. That is, when a filter is provided on the optical path of the reflected light, the amount of energy of the reflected light that should be reduced only during recording is reduced during reproduction, and it becomes difficult to secure the level of the RF signal. is there.
[0009] On the other hand, according to the above method 2, since the amount of energy of the reflected light is not reduced before receiving the light, it is possible to secure the level of the RF signal at the time of reproduction, but the photodetector has a configuration. This complicates the control method of the device itself.
[0010] The present application has been made in view of the circumstances described above, and as an example of the problem, even when the recording speed of data on an optical disk is improved, the circuit configuration is not complicated. An object of the present invention is to provide an optical pickup device and an information recording/reproducing device capable of ensuring an S/N ratio when reproducing an optical disc.
[Means for Solving the Problems]
[0011] In order to solve the above problems, in one aspect of the present application, an optical pickup device according to claim 1 outputs a plurality of light beams having different wavelengths.


Two

[0003]
An optical pickup device comprising a light source, irradiating the light beam onto a recording surface from one light source according to the type of the information recording medium, and receiving reflected light from the recording surface, the optical pickup device comprising: Light source control means for changing the light intensity of the optical container according to recording and reproduction, light receiving means for receiving the reflected light and outputting a signal according to the received light amount, and arranged on the optical path of the reflected light. A filter control unit that controls the transmission amount of the incident reflected light, and a filter control unit that controls the filter according to the light intensity of the light beam to control the transmission amount of the reflected light, The filter includes a light-absorbing layer whose absorption wavelength is variable depending on an applied voltage value, and an electrode that applies a voltage to the light-absorbing layer, and the filter control means includes the transparent electrode according to the type of the information recording medium. Is changed to change the absorption wavelength of the filter to reduce the transmission amount of the reflected light from the information recording medium.
[0012] In another aspect of the present application, an information recording/reproducing apparatus according to claim 4 includes a plurality of light sources that output light beams having mutually different wavelengths, and one of An information recording/reproducing apparatus comprising an optical pickup device for irradiating a recording surface with the light beam from one light source and receiving reflected light from the recording surface, wherein Light source control means for changing the light intensity of the light beam according to recording and reproduction, light receiving means for receiving the reflected light and outputting a signal according to the amount of received light, and arranged in the optical path of the reflected light and incident A filter that controls the transmission amount of the reflected light, and a filter control unit that controls the filter according to the light intensity of the light beam to control the transmission amount of the reflected light. A light-absorbing layer whose absorption wavelength is variable depending on the applied voltage value, and an electrode for applying a voltage to the light-absorbing layer, wherein the filter control means is provided for the transparent electrode according to the type of the information recording medium. By changing the voltage value applied by changing the absorption wavelength of the filter, the transmission amount of the reflected light from the information recording medium is reduced.
[Brief description of drawings]
[0013] [FIG. 1] A block diagram showing a configuration of an information recording/reproducing apparatus RP in the embodiment.
FIG. 2 is a diagram showing a configuration example in the case where the wavelength filter 18 in the same embodiment is configured by using an inorganic EC material.
FIG. 3 is a diagram showing a configuration example in the case where the wavelength filter 18 in the same embodiment is configured by using an organic EC material.
[Explanation of symbols]
[0014] RP... Information recording/reproducing device SP... Signal processing unit C... Control unit D... Driving circuit PU... Optical pickup S... Servo circuit P... Reproducing unit Best Mode for Carrying Out the Invention
[0015] [1] Embodiment (1) Overall configuration and operation outline


3/1

Claims (5)

An optical pickup device for irradiating a recording surface of an information recording medium with a light beam output from a light source and receiving reflected light from the recording surface,
Light source control means for changing the light intensity of the light beam according to recording and reproduction on the information recording medium,
A light receiving unit that receives the reflected light and outputs a signal according to the received light amount,
A filter that is disposed on the optical path of the reflected light and controls the amount of transmission of the reflected light that is incident,
Filter control means for controlling the filter according to the light intensity of the light beam to control the transmission amount of the reflected light,
An optical pickup device comprising: The filter is
A light absorption layer whose absorption wavelength varies depending on the applied voltage value,
An electrode that applies a voltage to the light absorption layer, and
The filter control means may reduce the amount of reflected light from the information recording medium by changing the voltage value applied to the transparent electrode to change the absorption wavelength of the filter. The optical pickup device according to claim 1.   The filter control means decreases the transmission amount when the light intensity of the light beam becomes strong, and increases the transmission amount when the light intensity of the light beam becomes weak. The optical pickup device according to claim 2.   4. The optical pickup device according to claim 1, wherein the filter is arranged at a predetermined angle with respect to the reflected light path. An information recording/reproducing apparatus including an optical pickup device for irradiating a recording surface of an information recording medium with a light beam output from a light source and receiving reflected light from the recording surface,
The optical pickup device,
Light source control means for changing the light intensity of the light beam according to recording and reproduction on the information recording medium,
A light receiving unit that receives the reflected light and outputs a signal according to the received light amount,
A filter that is arranged in the optical path of the reflected light and that controls the amount of transmission of the reflected light that is incident,
Filter control means for controlling the filter according to the light intensity of the light beam to control the transmission amount of the reflected light,
An information recording/reproducing apparatus comprising:

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