WO2006011314A1

WO2006011314A1 - Optical pickup device and information recording/reproducing device

Info

Publication number: WO2006011314A1
Application number: PCT/JP2005/011121
Authority: WO
Inventors: Naoharu Yanagawa; Fumihiko Sano
Original assignee: Pioneer Corporation
Priority date: 2004-07-23
Filing date: 2005-06-17
Publication date: 2006-02-02
Also published as: JPWO2006011314A1

Abstract

An S/N ratio at the time of reproducing an optical disk is ensured without making a circuit constitution complicated, even when the speed of recording data in the optical disk is improved. An optical pickup (PU) of an information recording/reproducing device (RP) is provided with a wavelength filter (18). The wavelength filter (18) is composed of, for instance, an EC (Electrochromic) material, and changes the light absorbing characteristic, in response to a voltage supplied from a control part (C). By using such function of the wavelength filter (18), the transmittance of reflecting light from an optical disk (DK) is maximized at the time of reproducing data recorded in the optical disk (DK), and at the time of recording data in the optical disk (DK), the transmittance of the reflecting light is reduced to reduce the energy quantity of the reflecting light applied on a photodetector (17).

Description

Specification

Optical pickup device and information recording / reproducing device

Technical field

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 disk.

Background art

[0002] Conventionally, in an information recording / reproducing apparatus for recording and reproducing 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 From the standpoint of discriminating from other products, the recording speed of data on optical discs such as DVD-R has been improved.

[0003] Here, an optical disc such as a DVD-R or DVD-RW has a constant temperature on the optical disc when the total energy of the light beam irradiated per unit time exceeds a predetermined threshold. When this value is exceeded, pigment discoloration or phase change occurs, which causes various data to be recorded. Therefore, the recording speed should be improved. When the rotational speed of the optical disk is increased, the optical disk is irradiated. Data cannot be recorded unless the amount of energy of the light beam is increased. Therefore, in order to improve the recording speed, it is essential to increase the amount of energy of the light beam output from the light source.

[0004] On the other hand, when the amount of energy of the light beam during recording is improved in this way, the difference between the amount of reflected light received by the photodetector during reproduction and the amount of light received by the photodetector during recording increases. The photodetector may not be able to receive the reflected light normally. For example, if a photodetector is designed so that an accurate RF signal can be obtained by reflected light during playback, the amount of reflected light energy during recording increases and exceeds the dynamic range of the photodetector. It is impossible to receive light.

[0005] Therefore, in the conventional information recording / reproducing apparatus, the amount of received light is adjusted when the recording speed is improved by employing the following method. [0006] <Method 1>

As for the optical disk force, a filter is provided on the optical path of the reflected light incident on the photodetector to reduce the amount of energy of the reflected light incident on the photodetector.

[0007] <Method 2>

A photo detector is configured using an OEIC that integrates various circuits such as light receiving elements and amplifier circuits, and the amplification factor of the amplifier circuit is switched at the time of data recording or reproduction on the optical disk, and the reflected light at the time of recording and reproduction is changed. It can receive light.

Disclosure of the invention

Problems to be solved by the invention

However, when the conventional method 1 is adopted, it becomes difficult to ensure the SZN ratio at the time of reproducing data recorded on the optical disk. In other words, if a filter is provided on the optical path of the reflected light, if it is reduced only during recording, the amount of energy of the reflected light will be reduced during reproduction, making it difficult to secure the RF signal level. It becomes.

[0009] On the other hand, according to the above method 2, the energy amount of the reflected light is not reduced before light reception, so that it is possible to secure the level of the RF signal at the time of reproduction. The configuration is complicated, and the device control method itself is complicated.

[0010] The present application has been made in view of the circumstances described above. As an example of the problem, even when the data recording speed to the optical disc is improved, the circuit configuration is complicated. An object of the present invention is to provide an optical pickup device and an information recording / reproducing device capable of ensuring an SZN ratio during reproduction of an optical disc.

Means for solving the problem

In order to solve the above-described problem, in one aspect of the present application, the optical pick-up device according to claim 1 irradiates the recording surface of the information recording medium with the light beam output from the light source force, and An optical pickup device that receives reflected light from a recording surface, the light source control means for changing the light intensity of the light beam in accordance with recording and reproduction on the information recording medium, and receiving the reflected light And a light receiving means for outputting a signal corresponding to the amount of received light, and a frame disposed on the optical path of the reflected light for controlling the amount of transmission of the incident reflected light. And a 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.

[0012] In another aspect of the present application, the information recording / reproducing apparatus according to claim 5 irradiates the recording surface of the information recording medium with the light beam output from the light source, and outputs the light beam from the recording surface. An information recording / reproducing apparatus including an optical pickup device that receives reflected light, wherein the optical pickup device changes light intensity of the optical beam according to recording and reproduction on the information recording medium. Means, a light receiving means for receiving the reflected light and outputting a signal corresponding to the amount of received light, a filter disposed in an optical path of the reflected light, for controlling a transmission amount of the incident reflected light, and the light beam And a filter control means for controlling the filter according to the light intensity to control the transmission amount of the reflected light.

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

FIG. 3 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

[0014] RP---Information recording / reproducing device

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

[0015] "1, embodiment

(1) Overall configuration and operation overview Hereinafter, the overall configuration and operation outline of the information recording / reproducing apparatus RP according to the present embodiment will be described with reference to FIG. 1 showing the schematic structure 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 that supports both CD and DVD standards.

As shown in the figure, 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, And a playback unit P.

[0017] The signal processing unit SP has an input terminal. The signal processing unit SP performs signal processing on data input through the terminal and outputs the data to the control unit C. Specific processing contents performed in the signal processing unit SP are arbitrary. For example, after the input data is compressed by a compression method such as MPEG (Moving Picture Experts Group), the data is processed by the control unit. You may make it output to.

[0018] 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.

[0019] 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.

[0020] The optical pickup PU is an optical disc based on a control signal supplied to the driving circuit D force. It is used to irradiate the DK with a light beam and to record and read data on the optical disc DK. In order to realize a powerful function, in this embodiment, the optical pickup PU includes, for example, a first light source 11, a second light source 12, an optical unit 2, a condensing lens 16, a photo detector 17, and a wavelength filter. 18 and.

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 should realize the recording and reproduction of data corresponding to both DVD and CD recording standards, and the first light source 11 has a wavelength of 660 ηm. The second light source 12 outputs a light beam having a wavelength of 780 nm. Each of these light sources 11 and 12 is selectively used depending on the type of the optical disc DK to be reproduced and recorded, 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 optical unit 2 includes a first beam splitter 13, a second beam splitter 14, And an actuator unit 15. The first beam splitter 13 and the second beam splitter 14 constituting the optical unit 2 are constituted by, for example, dichroic mirrors, and the actuator unit 15 has an objective lens (not shown). Further, the actuator unit 15 has a movable mechanism of the objective lens, and realizes tracking servo and focus servo by changing the position of the objective lens based on the control signal supplied from the servo circuit S. . When the first and second beam splitters 13 and 14 are configured by dichroic mirrors, the first beam splitter 13 reflects 90% of the 660 nm light beam, transmits 10%, and 100% of the 780 nm light beam. It is desirable to use a dichroic mirror that transmits light, a dichroic mirror that reflects 90% of the 780 nm light beam, transmits 10% and transmits 100% of the 660 nm light beam for the second beam splitter 14. .

The condensing lens 16 includes an objective lens of the actuator unit 15, first and second beam splitters.

Reflected light incident through 13 and 14 is condensed on the photodetector 17.

[0024] The photodetector 17 is constituted by, for example, a photodiode, and is formed from the condenser lens 16. The irradiated light beam is received and an RF signal is output to the control unit C, and signals necessary for tracking servo and focus servo are output to the servo circuit S.

[0025] Note that a specific method for realizing the tracking servo and the focus servo is arbitrary. For example, the photodetector 17 is divided into four parts, a cylindrical lens is used as the condensing lens 16, and the servo circuit S may be calculated in the servo circuit S using the astigmatism method for the focus servo. . For tracking servo, the servo circuit S can calculate the servo amount based on the amount of light received in each area where the photodetector 17 is divided.

The wavelength filter 18 has a configuration capable of changing the absorption wavelength and transmittance of the incident light beam under the control of the control unit C. Normally, in the information recording / reproducing apparatus RP, when trying to improve the data recording speed for the optical disc DK, the total amount of energy of the light beam applied to the optical disc DK per unit time exceeds a predetermined threshold, or the optical disc Since the temperature on the DK needs to be above a certain value, it is necessary to increase the amount of energy of the light beam irradiated to the optical disc DK. On the other hand, if the amount of light beam energy (recording power) is increased when recording data on the optical disc DK, the amount of reflected light received by the photodetector 17 when the optical beam DK is irradiated with the reproduction power. If the optical disc DK is irradiated with a recording power light beam, 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. Therefore, in the present embodiment, the transmission amount of the reflected light when the optical disc DK is irradiated with the light beam of recording power on the optical disc DK is reduced by the wavelength filter 18 and reaches the photodetector 17. A configuration that reduces the amount of reflected light energy is adopted. The specific configuration of the wavelength filter 18 will be described in detail in the next section.

In the information recording / reproducing apparatus RP having the above-described 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, 14, and the actuator It is incident on the objective lens of unit 15 and is focused on the optical disc DK. Thus, when the light beam is condensed on the optical disc DK, the light beam is After being reflected by the optical disc DK, the light again enters the first beam splitter 13 and the second beam splitter 14 through the objective lens of the actuator unit 15, and passes through the first beam splitter 13 and the second beam splitter 14. Then, the light 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, then enters the condenser lens 16, and is condensed on the photodetector 17 by the condenser lens 16. As a result, an RF signal is output from the photodetector 17 to the control unit C, and signals necessary for the tracking servo and focus servo are output to the servo circuit S.

[0028] When the RF signal is supplied from the photodetector 17, the control unit C outputs data corresponding to the RF signal to the reproduction unit P when reproducing the data recorded on the optical disc DK. P outputs the data to the outside. On the other hand, when recording data on the optical disc DK, the control unit C determines, for example, the acquisition timing of the address on the optical disc DK and the output timing of the drive signal corresponding to the data to be recorded based on this RF signal. . The servo circuit S calculates a 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 placement position of the objective lens is changed in the actuator unit 15, and tracking servo and focus servo are realized.

[0029] (2) Specific configuration and control of wavelength filter 18

Next, a specific configuration of the wavelength filter 18 and its control will be described.

First, according to the present embodiment, the wavelength filter 18 is configured using a material called an EC (Electrochromic) material, for example. This EC material is a material that causes the electochromism phenomenon in which the absorption wavelength reversibly changes depending on the applied voltage, and the transparent state force that is absorbed by the applied voltage only changes to a state that exhibits each color by absorbing only light of a predetermined frequency. It has the characteristics to There are two types of EC materials, inorganic and organic. Examples of inorganic EC materials include W03 (tungsten trioxide) and MoO 3 (molybdenum trioxide) using electroabsorption reaction. Power sword EC (colored by reduction) and Prussian blue (KxFeyFez (CN) 6), Nianod EC such as Ni (OH) n (colored by acid), and organic EL materials include organic EL There are functional polymers such as polyphenacillin that are used as (Electro Luminescent) materials. [0031] Fig. 2 shows a configuration example of the wavelength filter 18 when inorganic EC is used, and Fig. 3 shows a configuration example of the wavelength filter 18 when organic EC is used.

First, in FIG. 2, reference numeral 101 denotes a substrate, which is composed of a highly permeable base material such as Si02 (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 sol-gel method, a pulling method, vapor deposition, or the like, and then performing baking. Further, a transparent electrode 104 is further laminated on the EC layer 103. As a result, the electoric chromic layer 103 is formed between the transparent electrodes 102 and 104 in a sandwiched state. 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 in the EC layer 103. The light absorption characteristics will be reversibly changed.

[0033] Since the absorbance in the EC material differs depending on the material used, when designing the wavelength filter 18 specifically, it is based on the amount of reflected light energy during recording and the dynamic range of the photodetector 17. It is necessary to calculate the amount of reflected light that passes through the wavelength filter 18 and to change the thickness of the EC layer 103. For example, in the case of this embodiment, since a light beam having a wavelength of 660 nm and 780 nm is used, the reflected light of any wavelength is absorbed during data recording, and the photo data is recorded during data recording. It is necessary to reduce the amount of reflected light received by the tector 17. For this reason, for example, when PB (Prussian blue) is used as the EC layer 103, coloring from colorless to blue occurs when 0.2V is applied. It is possible to obtain ruta characteristics.

[0034] Next, when organic EC is used, the wavelength filter 18 is configured by bonding two transparent substrates 201 and 204 with a gap therebetween 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. As a result, 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, etc. need to be designed as appropriate, as in the case of using the above-mentioned inorganic EC material. is there.

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 optical axis in the filter 18.

[0036] If the wavelength filter 18 is installed closer to the actuator unit 15 than the first beam splitter 13 and the second beam splitter, before the optical beams DK are irradiated onto the optical disc DK, Since light absorption or reflection occurs, it is necessary to install the wavelength filter 18 closer to the photodetector 17 than the beam splitters 13 and 14.

[0037] 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, whereby the wavelength filter 18 The light absorption characteristics will be changed. Specifically, when reproducing data recorded on the optical disc 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 (i.e., transparent). In this state, the amount of reflected light energy reduced in the wavelength filter 18 is minimized. As a result, it is possible to minimize the reduction in the amount of reflected light incident on the photodetector 17 when reproducing the data recorded on the optical disc DK, and to secure the RF signal level during reproduction. .

[0038] In contrast, when data is recorded on the optical disc DK, that is, when the light beam is irradiated with the recording power, the control unit C controls the voltage applied to the wavelength filter 18 so as to obtain a predetermined frequency. The wavelength filter 18 is maintained in a state where the reflected light is absorbed and the transmittance of the reflected light is reduced. At this time, the control unit C determines the voltage value to be applied to the wavelength filter 18 depending on whether the optical disc DK to which data is recorded conforms to the CD standard or whether it conforms to the DVD standard. Change the absorption wavelength in the wavelength filter 18. As a result, the reflected light from the optical disc DK is incident on the photodetector 17 after the amount of energy is reduced in the wavelength filter 18. A light beam of recording power is output from either light source 11 or 12! However, the amount of reflected light received by the photodetector 17 is reduced to the same level as the reproduction power.

[0039] In this way, in the information recording / reproducing apparatus RP according to the present embodiment, the optical pickup PU records the light beam output from the first light source 11 or the second light source 12 on the optical disc DK. An optical pickup PU that irradiates the surface and receives reflected light from the recording surface, and controls the control unit C and drive circuit D to change the light intensity of the light beam in accordance with recording and reproduction on the optical disc DK. A photodetector 17 that receives reflected light from the optical disc DK and outputs a signal corresponding to the amount of received light, a wavelength filter 18 that is disposed in the optical path of the reflected light and controls the amount of transmitted reflected light, and a recording The control unit C is configured to control the wavelength filter 18 according to the light intensity of the light beam irradiated on the surface to control the transmission amount of the reflected light.

[0040] With this configuration, in accordance with the light intensity of the light beam applied to the recording surface of the optical disc DK, for example, the optical disc in the state where the recording surface of the optical disc DK is irradiated with the light beam of recording power. After the amount of energy of the reflected light from the DK is reduced by the wavelength filter 18, it is received by the photodetector 17. For this reason, the recording speed of data 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 properly adjusted. The photodetector 17 can receive the reflected light.

[0041] Further, in this configuration, since the amount of transmitted light reflected by the wavelength filter 18 can be changed based on the applied voltage from the control unit, the wavelength filter 18 can be used when recording data on the optical disc DK. The amount of reflected light from the optical disc DK is maximized when reproducing the data recorded on the optical disc DK, while ensuring the RF signal level at the time of data reproduction. It is also possible to secure the SZN ratio during optical disc playback.

[0042] Further, in the information recording apparatus RP according to the present embodiment, the wavelength filter 18 has an electrochromic layer 103 or 203 whose absorption wavelength is variable depending on an applied voltage value, and the electrochromic layer 103 or 203. And a transparent electrode for applying a voltage, The control unit C has a configuration in which the amount of reflected light transmitted from the optical disc DK is reduced by changing the voltage value applied to the transparent electrode to vary the absorption wavelength of the wavelength filter 18.

[0043] According to this configuration, it is possible to limit the transmission amount of the reflected light from the optical disc DK only by controlling the applied voltage to the electoric layer 103 or 203, and thus adopting a simple configuration. Appropriate light reception by the photodetector 17 can be realized.

[0044] Furthermore, the information recording / reproducing apparatus RP according to the present embodiment is configured so that the control unit C transmits when the light intensity of the light beam irradiated onto the recording surface of the optical disk DK becomes strong. The amount is reduced, and when the light intensity of the light beam becomes weak, the transmission amount is increased.

[0045] For this reason, the amount of reflected light transmitted through the wavelength filter 18 is controlled each time data is recorded and reproduced with respect to the optical disc DK, and the design of the photodetector 17 can be facilitated. Become. That is, even when the dynamic range of the photodetector 17 is narrow, the optical energy of the reflected light can be controlled by the wavelength filter 18, so that the optical beam DK is irradiated with the recording power. However, the amount of energy of the reflected light received by the photodetector 17 can be suppressed to the reproduction power level, and reliable light reception can be realized.

Further, in the information recording / reproducing apparatus RP that is useful in 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 disk DK. Therefore, even if a light beam reflected by the wavelength filter 18 is generated, stray light on the optical axis can be prevented.

[0047] In the above embodiment, V has been described as an example in which the wavelength filter 18 is made of an EC material. However, a material whose transmittance can be changed depending on temperature, such as a cholesteric liquid crystal, is described. The wavelength filter 18 may be used to control the voltage supplied from the control unit C so that a light beam having one of the wavelengths can be transmitted.

[0048] In the above embodiment, the apparatus RP for recording and reproducing information with respect to the optical disc DK corresponding to both the CD and DVD standards has been described. An apparatus for recording and reproducing information with respect to an optical disc DK corresponding to the standard of a ray disc and a CD or a Blu-ray disc and a DVD can be realized with the same configuration as described above.

[0049] Furthermore, in the present embodiment, the configuration is such that the light beams output from the first light source 11 and the second light source 12 are 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, and at the left and right of the area for receiving the main beam. Therefore, it is necessary to provide a region for receiving the sub 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 according to the present embodiment, an 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 has been described. Power These may be configured integrally with the optical pickup PU!

Claims

The scope of the claims

[1] Light source power An optical pickup device that irradiates a recording surface of an information recording medium with an output light beam and receives reflected light from the recording surface.

Light source control means for changing the light intensity of the light beam in accordance with recording and reproduction on the information recording medium;

A light receiving means for receiving the reflected light and outputting a signal corresponding to the amount of received light; a finer disposed on an optical path of the reflected light and controlling a transmission amount of the incident reflected light;

Filter control means for controlling the amount of transmission of the reflected light by controlling the filter according to the light intensity of the light beam;

An optical pickup device comprising:

[2] The filter is

A light-absorbing layer whose absorption wavelength varies depending on the applied voltage value;

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

The filter control means reduces a transmission amount of reflected light of the information recording medium force by changing a voltage value applied to the transparent electrode and changing an absorption wavelength of the filter. The optical pickup device according to claim 1.

[3] 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 1.

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

[5] Light source power An information recording / reproducing apparatus including an optical pickup device that irradiates a recording surface of an information recording medium with an output light beam and receives reflected light from the recording surface.

The optical pickup device is:

Light source control means for changing the light intensity of the light beam in accordance with recording and reproduction on the information recording medium; A light receiving means for receiving the reflected light and outputting a signal corresponding to the amount of received light; a filter disposed in an optical path of the reflected light and controlling a transmission amount of the incident reflected light;

An information recording / reproducing apparatus comprising: