WO2007052639A1

WO2007052639A1 - Optical pickup device, irradiating method, information recording device and information reproducing device, and computer program

Info

Publication number: WO2007052639A1
Application number: PCT/JP2006/321718
Authority: WO
Inventors: Naoharu Yanagawa; Akira Shirota
Original assignee: Pioneer Corporation
Priority date: 2005-10-31
Filing date: 2006-10-31
Publication date: 2007-05-10
Also published as: JPWO2007052639A1

Abstract

An optical pickup device (10) comprising a light source (11) for irradiating the recording surface of an information recording medium (100) with an output light, a light intensity controlling means (26) for controlling the light source so as to change the light intensity of the output light into an almost sinusoidal form, a filter (13) disposed on the light path of the output light to change the transmission amount of an incident output light, and a filter controlling means (27) for controlling the filter so as to change the transmission amount of the output light.

Description

Specification

Optical pickup device, irradiation method, information recording device, information reproducing device, and computer program

Technical field

[0001] The present invention relates to an optical pickup device used for recording and reproducing data on an information recording medium such as an optical disc, a method of irradiating emitted light in the optical pickup device, an information recording device and an information reproducing device including the optical pickup device, The present invention also relates to a computer program that causes a computer to operate as such an information recording device or information reproducing device. 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 DVD-R or DVD-RW has a constant temperature on the optical disc when the total amount of laser light irradiated per unit time exceeds a predetermined threshold. When the value exceeds the value, thermal decomposition or phase change of the dye occurs, whereby various data are recorded. For this reason, if the rotational speed of the optical disk is increased in order to increase the recording speed, data cannot be recorded unless the amount of laser beam energy (ie, laser beam power) applied to the optical disk is increased. Therefore, in order to improve the recording speed, it is essential to increase the power of the laser beam output from the light source.

Disclosure of the invention

Problems to be solved by the invention

However, in order to increase the power of the laser beam output from the light source, it is necessary to significantly increase the drive current of the laser drive circuit for driving the laser element that outputs the laser beam. . For example, in the case of a DVD which is a specific example of an optical disk, for example, a drive power of about 800 mA is used to output laser light with a power of about 300 mW. It is necessary to supply the current to the laser drive circuit force laser element. In order to further improve the recording speed, it is necessary to output laser light with a power greater than 300 mW, for example, and it is necessary to supply a large drive current of 800 mA or more to the laser element from the laser drive circuit, for example. Also come out.

[0005] Further, as the recording speed increases, the pulse width of the laser beam also decreases, for example, D

For VD 16x speed recording, it is necessary to output a strict square wave laser beam with a pulse width on the order of Ins to 30 ns.

[0006] However, it is possible to output a laser beam with a strict square wave shape having a short pulse width of about Ins by using a large drive current exceeding 800 mA, for example. If the operation of the circuit is difficult, it has technical problems. Furthermore, when a laser beam with a strict square wave shape with a short pulse width of approximately Ins is output using a large drive current exceeding 800 mA, for example, the amount of heat generated by the laser drive circuit is also greatly increased. It has the technical problem of increasing the amount of calories.

The present invention has been made in view of the above-described conventional problems, for example, an optical pickup device capable of performing a suitable recording operation while suppressing heat dissipation, and a method for irradiating emitted light. It is an object of the present invention to provide an information recording device, an information reproducing device, and a computer program.

Means for solving the problem

[0008] (Optical pickup device)

The optical pickup device of the present invention includes a light source for irradiating the recording surface of the information recording medium with the emitted light, a light intensity control means for controlling the light source so as to change the light intensity of the emitted light into a substantially sinusoidal shape, A filter disposed on the optical path of the outgoing light and configured to change a transmission amount of the incident outgoing light; and a filter control unit configured to control the filter so as to change the transmission amount of the outgoing light.

According to the optical pickup device of the present invention, the emitted light emitted from the light source including the laser element or the like is irradiated onto the recording surface of the information recording medium. The intensity of the emitted light is controlled by the operation of light intensity control means including a laser drive circuit. For example, when recording data on an information recording medium, there is no recording mark or recording pitch on the recording surface of the information recording medium. The emitted light is emitted from the light source with the first light intensity that is relatively strong (or relatively large) capable of forming a light source. Or, for example, when reproducing data recorded on an information recording medium, the recording mark formed on the recording surface of the information recording medium, or the recording pit is not destroyed or erased. The emitted light is emitted from the light source at a second light intensity that is relatively weak (or relatively small).

In the present invention, in particular, the light intensity of the emitted light is controlled by the operation of the light intensity control means so that the light intensity of the emitted light changes in a substantially sinusoidal waveform. Here, “change to a substantially sine wave shape” is intended to indicate a state in which the light intensity changes more slowly than when the light intensity is changed in a strict square wave shape. That is, it is intended to indicate a state in which the light intensity is increased relatively slowly and decreased relatively slowly by the operation of the light intensity control means.

[0011] Then, the emitted light emitted from the light source is incident on the recording surface of the information recording medium after entering the filter. The filter can increase or decrease the transmission amount of the outgoing light incident on the filter. How much outgoing light is transmitted is controlled by the operation of the filter control means. That is, the transmission amount of the filter is controlled by the operation of the filter control means. In the present invention, the filter control means changes the transmission amount of the filter so that the transmission amount of the filter changes in a substantially square wave shape.

In summary, according to the optical pickup device of the present invention, the emitted light emitted with the light intensity changing to a substantially sinusoidal shape passes through the filter, and the light intensity changing to the square wave shape is obtained. The recording surface of the information recording medium is irradiated. In other words, it is not necessary to change the light intensity of the emitted light into a strict square wave shape when the emitted light is irradiated from the light source. For this reason, the light intensity changing means can change the light intensity of the emitted light while suppressing the amount of heat generation. Even if the emitted light is emitted from the light source with a light intensity that changes in a substantially sinusoidal shape, the operation of the filter and the filter control means causes the emitted light to have a light intensity that changes to a square wave shape. Irradiates the recording surface. For this reason, a suitable recording mark or recording pit can be formed on the recording surface of the information recording medium, and as a result, data can be suitably recorded.

As a result of the above, according to the optical pickup device of the present invention, it is preferable to suppress heat dissipation and A recording operation can be performed.

In one aspect of the optical pickup device of the present invention, the filter control unit controls the filter so as to change a transmission amount of the filter according to data recorded on the information recording medium. .

[0015] According to this aspect, the emitted light is irradiated onto the recording surface of the information recording medium with the light intensity that changes to a square wave shape according to the data to be recorded. Therefore, a suitable recording mark or recording pit can be formed on the recording surface of the information recording medium, and as a result, data can be recorded suitably. Therefore, it is possible to perform a suitable recording operation while suppressing heat dissipation.

In another aspect of the optical pickup device of the present invention, the filter control means changes the transmission amount of the filter according to a strategy pulse corresponding to data recorded on the information recording medium. Control the filter.

According to this aspect, in accordance with the strategy pulse, the emitted light is irradiated onto the recording surface of the information recording medium with a light intensity that changes to a square wave shape. In other words, the light emitted from the light source is usually emitted with a light intensity that changes to a square wave shape according to the strategy pulse. In this aspect, the light is emitted with a light intensity that changes to a square wave shape according to the strategy pulse. The amount of transmission of the filter is changed so that the incident light passes through the filter. For this reason, even if the light intensity of the emitted light is not changed in a strict square wave shape when the emitted light is irradiated from the light source, the light source force is emitted in the same manner as when the emitted light is emitted with the light intensity changing to the square wave shape. The emitted light is applied to the recording surface of the information recording medium with a light intensity that changes to a square wave shape. Therefore, a suitable recording mark or recording pit can be formed on the recording surface of the information recording medium, and as a result, data can be recorded suitably. Therefore, a suitable recording operation can be performed while suppressing heat dissipation.

[0018] In the aspect of the optical pickup device that changes the transmission amount of the filter in accordance with the strategy pulse as described above, the strategy pulse includes a first pulse having a predetermined first amplitude and a first pulse smaller than the first amplitude. At least a second pulse having two amplitudes, wherein the filter control means increases the transmission amount of the filter in response to the first pulse than the transmission amount of the filter in response to the second pulse. Control the filter to Make it.

With this configuration, it is possible to suitably change the transmission amount of the filter according to the strategy pulse. Specifically, the transmission amount of the filter can be changed according to the amplitude of the strategy pulse. Therefore, a suitable recording mark or recording pit can be formed on the recording surface of the information recording medium, and as a result, data can be recorded suitably. Therefore, a suitable recording operation can be performed while suppressing heat dissipation.

In another aspect of the optical pickup device of the present invention, the light intensity control means controls the light source so as to change the light intensity of the emitted light according to data recorded on the information recording medium. Control.

[0021] According to this aspect, the light source emits the emitted light having a light intensity that changes in a substantially sinusoidal shape according to the recorded data.

In another aspect of the optical pickup device of the present invention, the light intensity control means changes the light intensity of the emitted light according to a strategy pulse corresponding to data recorded on the information recording medium. The light source is controlled.

[0023] According to this aspect, the emitted light having the light intensity that changes in a substantially sinusoidal shape in accordance with the strategy pulse is irradiated with the light source power. In other words, the emitted light is usually emitted with a light intensity that changes to a square wave shape according to the strategy pulse. In this aspect, the light intensity changes to a substantially sine wave shape according to the strategy pulse. Outgoing light is emitted from the light source.

[0024] In the aspect of the optical pickup device that changes the light intensity of the emitted light according to the strategy pulse as described above, the strategy pulse is smaller than the first pulse having a predetermined first amplitude and the first amplitude. At least a second pulse having a second amplitude, and the light intensity control means has a light intensity of the emitted light according to the first pulse, and the light intensity of the emitted light according to the second pulse. You may comprise so that the said light source may be controlled so that it may become larger than intensity | strength.

[0025] With this configuration, even if the light intensity of the emitted light emitted from the light source does not change to a square wave shape according to the strategy pulse, it is a substantially sine string that changes with a tendency similar to that of the square wave shape. It changes to a wave shape. [0026] Another aspect of the optical pickup device of the present invention is that each phase of rise and fall in the increase and decrease of the light intensity of the emitted light and each phase of rise and fall in the change of the transmission amount of the filter And a synchronizing means for synchronizing the.

[0027] According to this aspect, the phase of the rise in the increase or decrease in the light intensity of the emitted light (that is, the period during which the light intensity increases) and the rise in the change in the transmission amount of the filter (that is, the transmission of the filter). It is possible to synchronize with the phase of the period during which the amount increases. In addition, the phase of the fall (that is, the period during which the light intensity decreases) in the increase and decrease of the light intensity of the emitted light and the fall (that is, the transmission quantity of the filter decreases) in the change in the transmission amount of the filter. ) Phase can be synchronized. It is possible to reduce or eliminate the situation where unnecessary blocking or unnecessary transmission of emitted light in the filter occurs.

[0028] In the aspect of the optical pickup device further including the synchronization unit as described above, the optical pickup device further includes a monitoring unit that monitors the light intensity of the emitted light that has passed through the filter, and the synchronization unit integrates the monitored light intensity. The phase may be synchronized by comparing the value with a predetermined reference value.

[0029] With this configuration, by comparing the monitored integrated value of the light intensity with the reference value, each phase of rising and falling in the increase and decrease of the light intensity of the emitted light, and the filter It is possible to relatively easily synchronize the rising and falling phases in changing the transmission amount.

[0030] In the aspect of the optical pickup device further including the monitoring unit as described above, if the integrated value of the light intensity of the emitted light at time t is V (t), the synchronization unit is V (t + At) — It may be configured to synchronize the phase so that V (t) takes 0 or the maximum value! /.

[0031] Since the light intensity of the outgoing light after passing through the filter changes to a square wave shape, the outgoing light after passing through the filter has its pulse in the ON state or its pulse in the OFF state. There can be two states. Therefore, with this configuration, by comparing the integrated values of the light intensity monitored in successive time zones, the rising and falling phases in the increase and decrease of the light intensity of the emitted light, and the transmission of the filter It is possible to relatively easily synchronize the rising and falling phases in changing the quantity. The operation of comparing the integrated value of the monitored light intensity with the reference value is the monitoring This is equivalent to the operation for determining whether the integrated value of the light intensity is 0 or a maximum value.

[0032] In another aspect of the optical pickup device of the present invention, the filter includes a light absorption layer whose absorption wavelength varies depending on a value of an applied voltage, and an electrode that applies the voltage to the light absorption layer. The filter control means controls the filter so as to change a transmission amount of the filter by changing a value of the voltage applied to the electrode.

[0033] According to this aspect, the transmission amount of the filter can be increased or decreased by changing the voltage applied to the light absorption layer.

[0034] In another aspect of the optical pickup device of the present invention, the filter applies a liquid crystal layer including a liquid crystal element whose molecular arrangement changes depending on a value of an applied voltage, and the voltage to the liquid crystal layer. The filter control means controls the filter so as to change the transmission amount of the filter by changing the value of the voltage applied to the electrode.

According to this aspect, the transmission amount of the filter can be increased or decreased by changing the voltage applied to the liquid crystal layer.

In another aspect of the optical pickup device of the present invention, the filter is disposed with a predetermined angle with respect to the optical path of the emitted light.

[0037] According to this aspect, it is possible to suitably eliminate stray light generation factors that can be generated by being reflected in the output light power filter incident on the filter.

[0038] (Irradiation method)

An irradiation method of the present invention comprises an optical pickup comprising: a light source that irradiates a recording surface of an information recording medium with emitted light; and a filter that is disposed on an optical path of the emitted light and changes a transmission amount of the incident emitted light. A method of irradiating the emitted light in an apparatus, wherein a light intensity control step of controlling the light source so as to change a light intensity of the emitted light into a substantially sinusoidal shape, and changing a transmission amount of the emitted light. A filter control step for controlling the filter.

[0039] According to the irradiation method of the present invention, it is possible to receive the same benefits as the benefits of the optical pickup device of the present invention described above.

[0040] Incidentally, in response to the various aspects of the optical pickup device of the present invention described above, The irradiation method can also take various forms.

[0041] (Information recording device)

An information recording apparatus of the present invention includes a light source that irradiates a recording surface of an information recording medium with emitted light, and a light intensity control unit that controls the light source so as to change the light intensity of the emitted light into a substantially sinusoidal shape. A filter that is disposed on the optical path of the emitted light and that changes a transmission amount of the incident outgoing light, a filter control unit that controls the filter to change the transmission amount of the outgoing light, and the information Recording means for recording data on a recording medium. That is, an information recording apparatus of the present invention includes the above-described optical pickup apparatus of the present invention (including various aspects thereof) and recording means for recording data on the information recording medium.

According to the information recording apparatus of the present invention, it is possible to record data on the information recording medium while enjoying the same benefits as the benefits of the above-described optical pickup device of the present invention.

Incidentally, in response to the various aspects of the optical pickup apparatus of the present invention described above, the information recording apparatus of the present invention can also adopt various aspects.

[0044] (Information Reproducing Device)

An information reproducing apparatus of the present invention includes a light source that irradiates a recording surface of an information recording medium with emitted light, and a light intensity control unit that controls the light source so as to change the light intensity of the emitted light into a substantially sinusoidal shape. A filter that is disposed on the optical path of the emitted light and that changes a transmission amount of the incident outgoing light, a filter control unit that controls the filter to change the transmission amount of the outgoing light, and the information Playback means for playing back data recorded on the recording medium. That is, an information recording apparatus according to the present invention includes the above-described optical pickup apparatus according to the present invention (including various aspects thereof) and reproducing means for reproducing data recorded on the information recording medium.

According to the information reproducing apparatus of the present invention, it is possible to reproduce the data recorded on the information recording medium while enjoying the same benefits as those enjoyed by the optical pickup device of the present invention described above. Monkey.

Incidentally, in response to the various aspects of the optical pickup apparatus of the present invention described above, the information reproducing apparatus of the present invention can also adopt various aspects.

[0047] (Computer program) A first computer program of the present invention is a recording control computer program for controlling a computer provided with the above-described information recording apparatus of the present invention (including various aspects thereof), It functions as at least a part of the light intensity control means and the filter control means.

[0048] A second computer program of the present invention is a computer program for reproduction control for controlling a computer provided with the above-described information reproduction apparatus of the present invention (including various aspects thereof), A computer is caused to function as at least part of the light intensity control means and the filter control means.

[0049] According to each computer program according to the present invention, if the computer program is read from a recording medium such as a ROM, CD-ROM, DVD-ROM, or hard disk storing the computer program and then executed by the computer. Alternatively, if the computer program is downloaded to a computer via communication means and then executed, the above-described information recording apparatus or information reproducing apparatus of the present invention can be realized relatively easily.

[0050] Incidentally, in response to the various aspects of the information recording apparatus or information reproducing apparatus of the present invention described above, each computer program of the present invention can also adopt various aspects.

[0051] In order to solve the above problems, a first computer program product in a computer-readable medium is obtained by a computer provided with the above-described information recording apparatus (including various aspects thereof) of the present invention. Executable program instructions are clearly embodied, and the converter functions as at least a part of the light intensity control means and the filter control means.

[0052] In order to solve the above problems, a second computer program product in a computer-readable medium is obtained by a computer provided with the above-described information reproducing apparatus of the present invention (including various aspects thereof). Executable program instructions are clearly embodied, and the converter functions as at least a part of the light intensity control means and the filter control means.

[0053] According to the first or second computer program product of the present invention, a record such as a ROM, a CD-ROM, a DVD-ROM, or a hard disk for storing the computer program product. If the computer program product is read from a medium into a computer, or if the computer program product, which is a transmission wave, for example, is downloaded to a computer via communication means, the information recording apparatus or information reproducing apparatus of the present invention described above Can be implemented relatively easily. More specifically, the computer program product may also be configured with computer-readable code (or computer-readable instructions) that functions as the information recording apparatus or information reproducing apparatus of the present invention described above.

[0054] These effects and other advantages of the present invention will become more apparent from the embodiments described below.

[0055] As described above, the optical pickup device of the present invention includes a light source, a light intensity control means, a filter, and a filter control means. Therefore, a suitable recording operation and reproduction operation can be performed while suppressing heat dissipation.

[0056] The irradiation method of the present invention includes a light intensity control step and a filter control step. Therefore, it is possible to perform a suitable recording operation and reproducing operation while suppressing heat dissipation.

[0057] The information recording apparatus of the present invention includes a light source, a light intensity control means, a filter, a filter control means, and a recording means. Therefore, a suitable recording operation can be performed while suppressing heat dissipation.

[0058] According to the information reproducing apparatus of the present invention, the light source, the light intensity control means, the filter, the filter control means, and the reproduction means are provided. Therefore, a suitable reproduction operation can be performed while suppressing heat dissipation.

Brief Description of Drawings

FIG. 1 is a block diagram conceptually showing the basic structure of an information recording / reproducing apparatus in a first example.

FIG. 2 is a sectional view conceptually showing a first specific example of the filter.

FIG. 3 is a sectional view conceptually showing a second specific example of the filter.

FIG. 4 is a sectional view conceptually showing a third specific example of the filter.

[Fig. 5] Waveform of recording strategy according to recording signal (recording data), light intensity of light beam emitted from laser diode, transmission amount of filter, and light intensity of light beam irradiated to optical disk, respectively It is a graph which shows notably the mode of the change along a time-axis. FIG. 6 is a waveform diagram showing overshoot and undershoot of a light beam.

[7] FIG. 7 is a block diagram conceptually showing the basic structure of the information recording / reproducing apparatus in the second example.

[FIG. 8] When the timing of changing the transmission amount of the filter is not shifted, the light intensity of the light beam emitted from the laser diode, the transmission amount of the filter, and the light intensity of the light beam emitted to the optical disc are It is a graph which shows notionally the mode of change along a time axis.

[FIG. 9] The light intensity of the light beam emitted from the laser diode, the transmission quantity of the filter, and the light intensity of the light beam emitted to the optical disk when the timing of changing the transmission quantity of the filter is shifted. , Is a graph conceptually showing the state of change along the time axis

[0060] 1, 2 Information recording / reproducing apparatus

10, 10a optical pickup

11 Laser diode

12 Front monitor

13 Huinoleta

24 CPU

26 Laser drive

27 Filter element drive circuit

31 Integration circuit

32 Reference value storage circuit

33 Contortor

34 Phase compensation servo circuit

50 optical disc

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described in each embodiment in order with reference to the drawings. In the following embodiments, the embodiments relating to the optical pickup device of the present invention are described. We will explain the information recording / playback device that can record and play back data on various optical disks such as CD, DVD, Blu-my Disc, etc.

[0062] (1) First Example

(1-1) Basic configuration of information recording / reproducing device

First, the basic configuration of the information recording / reproducing apparatus in the first example will be described with reference to FIG. FIG. 1 is a block diagram conceptually showing the basic structure of the information recording / reproducing apparatus in the first example.

As shown in FIG. 1, the information recording / reproducing apparatus 1 according to the first embodiment includes an optical pickup 10, a photo detector (PD) amplifier 21, a reproducing circuit 22, a CPU 24, and a recording A circuit 25, a laser drive circuit 26, a filter element drive circuit 27, and a spindle motor 28 are provided.

The optical pickup 10 is used to irradiate the optical disc 50 with a light beam and to record and reproduce data on the optical disc 50. In order to realize a powerful function, the optical pickup 10 includes a laser diode 11, a filter 13, a beam splitter 14, an objective lens 15, a condenser lens 16, and a photodetector 17.

The laser diode 11 constitutes a specific example of the “light source” in the present invention. Based on the drive signal supplied from the laser drive circuit 26, the laser diode 11 emits one type or plural types of light beams having different wavelengths. Irradiate. For example, when data is recorded and reproduced on a DVD constituting a specific example of the optical disk 50, the laser diode 11 irradiates a light beam having a wavelength of approximately 660 nm. For example, when data is recorded and reproduced on a CD constituting a specific example of the optical disc 50, the laser diode 11 irradiates a light beam having a wavelength of approximately 780 nm. For example, when recording and reproducing data on a Blu-ray Disc constituting a specific example of the optical disc 50, the laser diode 11 irradiates a light beam having a wavelength of approximately 405 nm.

The filter 13 has a configuration capable of changing the transmission amount of the light beam incident on the filter 13 (that is, the transmittance for the light beam incident on the filter 13) under the control of the filter element drive circuit 27. is doing. The specific configuration of the filter 13 will be described in detail later (see FIGS. 2 to 4). [0067] The beam splitter 14 reflects 90% of the light beam, which is also incident on the side force of the laser diode 11, to the optical disk 50 and transmits 10%, and is incident from the optical disk 50 side. The light beam (that is, the light reflected from the optical disk 50) is transmitted 100% as it is.

The objective lens 15 emits an incident light beam and irradiates the recording surface of the optical disc 50.

[0069] The condensing lens 16 condenses the light beam transmitted through the beam splitter 14 as it is (that is, the light beam reflected from the optical disk 50) and irradiates the light receiving surface of the photodetector 17 with the light beam. .

[0070] The photodetector 17 is configured by, for example, a photodiode, receives the light beam emitted from the condenser lens 16, and sends a detection signal corresponding to the power of the received light beam to the photodetector amplifier 21. Output.

The photodetector amplifier 21 generates an RF signal from the detection signal output from the photodetector 17 and outputs the RF signal to the reproduction circuit 22.

[0072] The reproduction circuit 22 constitutes one specific example of the "reproduction means" in the present invention. The RF signal output from the photodetector amplifier 21 is demodulated, decoded, or error-corrected. Or a decoding process or the like to generate a reproduction signal. The reproduction circuit 22 outputs the generated reproduction signal to an external display, a speaker or the like, and as a result, it is reproduced as data power recorded on the optical disc 50, for example, video content, audio content, or other content.

[0073] The CPU 24 is connected to each component of the information recording / reproducing apparatus 1 via a bus, and controls the entire information recording / reproducing apparatus 1 by giving an instruction to each component. Usually, software or firmware for the CPU 24 to operate is stored in a memory in the information recording / reproducing apparatus 1.

The recording circuit 25 constitutes one specific example of “recording means” in the present invention, and corrects errors with respect to recording data input from the outside as data for recording on the optical disk 50. A recording signal is generated by performing code addition processing, modulation processing, encryption processing, encoding processing, and the like. The generated recording signal is output to the laser drive circuit 26. The laser drive circuit 26 constitutes a specific example of the “light intensity control means” of the present invention under the control of the CPU 24, and a drive signal for controlling the operation of the laser diode 11 is transmitted to the laser diode. Output to 11. More specifically, when recording data on the optical disc 50, the laser drive circuit 26 uses a predetermined power as a write light or a power (hereinafter referred to as a power value output from the CPU 24). And a recording signal that is irradiated with a light beam while being modulated in accordance with the recording signal output from the recording circuit 25, and outputs it to the laser diode 11. Alternatively, when reproducing the data recorded on the optical disc 50, the laser drive circuit 26 uses a predetermined power as reading light or a power corresponding to a power value output from the CPU 24 (hereinafter referred to as “reproduction power”). T)) Generate a drive signal that is irradiated with the light beam and output it to the laser diode 11.

The filter element drive circuit 27 constitutes a specific example of the “filter control means” of the present invention under the control of the CPU 24, and controls the change in the transmission amount of the light beam incident on the filter 13. It is configured to be possible.

The spindle motor 28 rotates and stops the optical disc 50, and operates when accessing the optical disc 50. More specifically, the spindle motor 28 is configured to rotate and stop the optical disc 50 at a predetermined speed while receiving spindle servo from a servo unit (not shown) or the like.

In the information recording / reproducing apparatus 1 having the above-described configuration, the light beam emitted from the laser diode 11 is incident on the filter 13. At this time, the light beam irradiated from the laser diode 11 is controlled by the filter 13 and then reflected by the beam splitter 14, enters the objective lens 15, and is condensed on the optical disk 50. When the light beam is collected on the optical disk 50 in this way, the light beam is reflected by the optical disk 50 and then enters the beam splitter 14 again through the objective lens 15, so that the beam splitter 14 Transparent. Thereafter, the light enters the condensing lens 16 and is condensed on the photodetector 17 by the condensing lens 16 mm. As a result, a light reception signal is output from the photodetector 17 to the photodetector amplifier 21, and an RF signal is output from the photodetector amplifier 21 to the reproduction circuit 22. [0079] When the RF signal is output from the photodetector 17, the CPU 24 controls the reproduction circuit 22 to reproduce the data corresponding to the RF signal when reproducing the data recorded on the optical disc 50, The reproduction circuit 22 outputs the data to the outside. On the other hand, when data is recorded on the optical disc 50, the CPU 24 determines the output timing of the drive signal corresponding to the address acquisition and data to be recorded on the optical disc 50 based on this RF signal, for example.

[0080] (1-2) Basic filter configuration

Next, a specific configuration of the filter 13 will be described with reference to FIGS. FIG. 2 is a sectional view conceptually showing a first specific example of the filter 13, and FIG. 3 is a sectional view conceptually showing a second specific example of the filter 13, and FIG. FIG. 5 is a sectional view conceptually showing a third specific example of the filter 13.

First, in the present embodiment, the filter 13 can be 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. Transparent state force is absorbed by the applied voltage, and changes to a state in which each color is exhibited 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 (colored by acid) such as Ni (OH) n, and organic EL materials are organic EL There are functional polymers such as polyphenacillin that are used as (Electro Luminescent) materials.

[0082] As shown in Fig. 2, the first specific example of the filter 13 (hereinafter referred to as "filter 13a") is made of a highly permeable base material such as Si02 (acid-silicon). A substrate 101 is provided. A transparent electrode 102 is formed on the substrate 101, and an EC layer 103 is formed on the transparent electrode 102 by film formation by a sol-gel method, a pulling method, vapor deposition, or the like, followed by baking. A transparent electrode 104 is further laminated on the EC layer 103. As a result, the EC layer 103 is sandwiched between the transparent electrode 102 and the transparent electrode 104. The transparent electrode 102 and the transparent illumination 104 are respectively connected to the filter element drive circuit. The filter element drive circuit 27 is connected to a power source provided in the path 27, and the filter element drive circuit 27 applies a predetermined voltage between the transparent electrode 102 and the transparent electrode 104 to thereby absorb light in the EC layer 103. (For example, the absorption wavelength) is reversibly changed. That is, the transmission amount of the light beam incident on the filter 13a is reversibly changed.

[0083] Since the absorbance in the EC material varies depending on the material to be used, when specifically designing the filter 13a, the filter 13a allows the light beam irradiated from the laser diode 11 to pass through the filter 13a. It is preferable to determine the thickness of the EC layer 103, the EC material used for the EC layer 103, the magnitude of the voltage applied to the EC layer 103, etc., depending on how much it is reduced.

Next, when an organic EC material is used, as shown in FIG. 3, a second specific example of the filter 13 (hereinafter referred to as “filter 13b”) includes two transparent substrates 111 and 114. And an EC layer 113 composed of an organic EC material member is filled between the transparent substrate 111 and the transparent substrate 114. On the opposing surfaces of the transparent substrate 111 and the transparent substrate 114, a transparent electrode 112 and a transparent electrode 115 are formed. Each of the transparent electrode 112 and the transparent electrode 115 is connected to a power source provided in the filter element drive circuit 27, and the filter element drive circuit 27 is provided between the transparent electrode 112 and the transparent electrode 115. By applying a constant voltage, the light absorption characteristics in the EC layer 113 are reversibly changed. That is, the transmission amount of the light beam incident on the filter 13b is reversibly changed.

Even in this case, it is necessary to appropriately design the thickness, applied voltage value, and the like of the EC layer 113, as in the EC layer 103 in which the inorganic EC material force is also configured.

[0085] In addition to or instead of using the EC material, the filter 13 can also be configured using a liquid crystal material such as a cholestic liquid crystal. The transmittance of the cholestic liquid crystal can be changed according to the applied voltage and temperature. Specifically, as shown in FIG. 4, in the third specific example of the filter 13 (hereinafter referred to as “filter 13c”), two transparent substrates 121 and 124 are bonded together with a gap between them. A liquid crystal layer 123 composed of a liquid crystal material is filled between the transparent substrate 121 and the transparent substrate 124. A transparent electrode 122 and a transparent electrode 125 are formed on the opposing surfaces of the transparent substrate 121 and the transparent substrate 124, respectively. Has been. Each of the transparent electrode 122 and the transparent electrode 125 is connected to a power source provided in the filter element drive circuit 27, and the filter element drive circuit 27 is provided between the transparent electrode 122 and the transparent electrode 125. By applying this voltage, the liquid crystal layer 123 is constituted, and the alignment characteristics of the liquid crystal molecules contained in the liquid crystal material are reversibly changed. That is, the transmission amount of the light beam incident on the filter 13c is reversibly changed. Even in this case, it is necessary to appropriately design the thickness, applied voltage value, etc. of the liquid crystal layer 123 because the EC layer 103 also includes the above-described inorganic EC material force and the EC layer 113 that also includes the organic EC material force. It is the same.

[0086] In addition to or instead of using the above-described inorganic EC material, organic EC material, and liquid crystal material such as stick liquid crystal, a photopolymer, a photorefractive liquid crystal, an isomerized material, or a fluorescent dye is used. Thus, the filter 13 described above can also be configured.

[0087] The filter 13 described above is preferably made of a material that can change the amount of transmission in the order of picoseconds or in the order of femtoseconds. In other words, it is possible to switch from a low transmission level to a high !, state, or a high transmission level !, from a low state to a state, on the order of picoseconds or femtoseconds. It is preferable to configure the filter 13 using a material. However, the filter 13 may be configured using a material capable of switching from a low transmission amount to a high state or from a high transmission amount to a low state on the order of nanoseconds. ,.

[0088] (1-3) Operating Principle of Information Recording / Reproducing Device

Next, with reference to FIG. 5 and FIG. 6, the operation principle of the information recording / reproducing apparatus in the first example will be explained. FIG. 5 shows the waveform of the recording strategy according to the recording signal (recording data), the light intensity of the light beam emitted from the laser diode 11, the transmission amount of the filter 13, and the light beam emitted to the optical disc 50. FIG. 6 is a graph conceptually showing how the light intensity changes along the time axis, and FIG. 6 is a waveform diagram conceptually showing the overshoot and undershoot of the light beam.

[0089] In the following description of the operating principle, according to the recording signal output from the recording circuit 25 to the laser drive circuit 26, the light beam whose light intensity changes with the waveform shown in FIG. Assuming that data is required to be recorded on the optical disc 50 Proceed with the explanation. In other words, the light beam can be irradiated with a light intensity that changes with the waveform shown in Fig. 5 (a), and the light beam is applied according to a strategy pulse having a waveform substantially similar to the waveform shown in Fig. 5 (a). The explanation will be made assuming that it is necessary to irradiate.

In this case, the laser drive circuit 26 drives the laser diode 11 so as to irradiate an optical beam that changes with the light intensity shown in FIG. 5 (b). More specifically, the laser drive circuit 26 has the exact square wave shape shown in FIG. 5 (a) while the timing or phase of the rise and fall of the waveform shown in FIG. The laser diode 11 is driven so that the light intensity of the light beam changes in such a manner that it rises more slowly than the waveform and falls more slowly. More specifically, the laser drive circuit 26 drives the laser diode 11 so that the light intensity changes in a substantially sinusoidal waveform shown in FIG. During a period in which the amplitude of the waveform shown in FIG. 5 (a) is relatively large, the laser drive circuit 26 drives the laser diode 11 so that the light intensity of the light beam becomes relatively large. On the other hand, during the period when the amplitude of the waveform shown in FIG. 5 (a) is relatively small, the laser drive circuit 26 drives the laser diode 11 so that the light intensity of the light beam becomes relatively small.

[0091] In response to the change in the light intensity of the light beam shown in FIG. 5B, the filter control circuit 27 causes the transmission amount to change with the same or substantially the same waveform as that shown in FIG. 5A. For example, a predetermined voltage is applied to the filter 13. More specifically, the filter control circuit 27 adjusts the voltage applied to the filter 13 so as to change with the waveform shown in FIG. 5 (a). Thus, the transmission amount of the filter 13 is controlled. That is, during a period when the amplitude of the waveform shown in FIG. 5A is relatively large, the filter element drive circuit 27 applies a predetermined voltage to the filter 13 so that the transmission amount of the filter 13 is relatively large. To do. On the other hand, during a period in which the amplitude of the waveform shown in FIG. 5A is relatively small, the filter element drive circuit 27 applies a predetermined voltage to the filter 13 so that the transmission amount of the filter 13 is relatively small. .

As a result, the light beam irradiated from the laser diode 11 so that the light intensity changes in the waveform shown in FIG. 5 (b) passes through the filter 13 whose transmission amount changes in the waveform shown in FIG. 5 (c). By transmitting the light, the optical intensity is changed with the waveform shown in FIG. Is done.

As described above, according to the first embodiment, the laser drive circuit 26 needs to drive the laser diode 11 so as to change the light intensity in the form of a strict square wave shown in FIG. 5 (a). It ’s gone. More specifically, the laser diode is changed so as to change the light intensity in the shape of a square wave in which the light intensity suddenly or instantaneously increases tl and the light intensity sharply or instantaneously decreases. There is no need to drive. As a result, the laser diode 11 may be driven so as to change the light intensity in a substantially sinusoidal shape in which the light intensity increases relatively slowly and the light intensity decreases relatively slowly. In other words, the laser drive circuit 26 does not need to drive the laser diode 11 so as to irradiate a square-wave light beam having a relatively short pulse width (that is, high-speed and suddenly ONZOFF). The diode 11 can be driven suitably. Furthermore, the amount of heat generated when the laser drive circuit 26 drives the laser diode 11 can be relatively reduced.

[0094] Even if the laser diode 11 is not driven so as to change the light intensity with a strict square wave, the light beam passes through the filter 13 whose transmission amount changes in the waveform shown in Fig. 5 (c). Thus, the optical disk 50 can be irradiated with the same light beam as when the laser diode 11 is driven so as to change the light intensity with a strict square wave. As a result, data can be suitably recorded on the optical disc 50.

[0095] By using the filter 13, it is possible to optically change the light intensity of the light beam, so compared with the case where the laser drive circuit 26 changes the light intensity of the light beam. The waveform of the light beam can be controlled with higher accuracy.

[0096] Furthermore, the transmission amount is low, the state is high !, the state is switched, or the transmission amount is high !, the state is low, the state is switched on the order of picoseconds or is femtoseconds. By using the filter 13 that can be ordered, the optical disk 50 can be suitably irradiated with a light beam having a pulse width that is extremely short even if the recording speed increases in the future.

[0097] Error! There is an error in the hyperlink reference. error! There is an error in the hyperlink reference. Furthermore, since the light intensity of the light beam can be optically changed, the occurrence of overshoot and undershoot of the light beam as shown in FIG. 6 can be suppressed. You can. For this reason, it is possible to relatively expand the permissible range of variations in the parameters of the laser diode 11 that cause overshoot or undershoot. This makes it possible to relatively widen the design width of the laser diode 11 (for example, the material selection width). In addition, the characteristics of the information recording / reproducing apparatus 1 such as the waveform of the light beam applied to the optical disc 50 can be made relatively easy.

This is more effective particularly when the data recording speed on the optical disc 50 is increased. In other words, if the recording speed of data on the optical disc 50 increases, the pulse width of the optical beam becomes shorter and shorter. The waveform of the optical beam can be controlled by using the filter 13, so that the burden of the laser drive circuit 26 is reduced. Does not increase so rapidly. Therefore, the amount of increase in the amount of heat generated by the laser drive circuit 26 can be suppressed as compared with the amount of decrease in the pulse width due to the increase in recording speed.

[0099] When overshoot or undershoot occurs, a filter that has a transmittance of "0" above a certain power or a transmittance of "0" above a certain power is used. It is preferable to remove shoots and undershoots. As such a filter, an optical amplifier, a light control glass, or the like can be used.

[0100] In the first embodiment described above, the laser drive circuit 26 drives the laser diode 11 so as to irradiate a light beam whose light intensity changes to a substantially sinusoidal shape. Even if the laser diode 11 is driven so as to irradiate a light beam having a constant light intensity, the above-mentioned various benefits can be enjoyed accordingly. In other words, even if the laser diode 11 is driven so as to irradiate the light beam with a DC level light intensity, the above-described various benefits can be enjoyed accordingly.

[0101] When the filter 13 is employed, a light beam reflected by the filter 13 can be generated in addition to the light beam transmitted or absorbed. In this case, if the filter 13 is installed at an angle with the incident axis of the light beam as a normal line, the light beam reflected on the filter 13 may stray on the optical axis. Therefore, it is preferable to install the filter 13 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 13! /.

[0102] Power! The rise and fall of the change in the light intensity of the light beam shown in Fig. 5 (b) Phase (or increase / decrease tendency or ONZOFF timing of the light beam) and the rising and falling phases (or increase / decrease tendency or filter) of the change in the transmission amount of the filter 13 shown in FIG. It is preferable to align or match the ONZOFF timing of 13 transmission amount changes). A mode in which the phases are aligned or matched will be described in more detail in the second embodiment.

[0103] (2) Second Example

Subsequently, an information recording / reproducing apparatus according to the second embodiment will be described with reference to FIGS. FIG. 7 is a block diagram conceptually showing the basic structure of the information recording / reproducing apparatus in the second example. FIG. 8 is a diagram in the case where the timing for changing the transmission amount of the filter 13 is not shifted. A graph conceptually showing how the light intensity of the light beam emitted from the laser diode 11, the transmission amount of the filter 13, and the light intensity of the light beam emitted to the optical disc 50 change along the time axis. FIG. 9 shows the light intensity of the light beam irradiated from the laser diode 11, the transmission amount of the filter 13, and the light beam irradiated to the optical disc 50 when the timing of changing the transmission amount of the filter 13 is shifted. It is a graph which shows notionally how the light intensity changes along the time axis.

Note that in the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

As shown in FIG. 7, the information recording / reproducing apparatus 2 according to the second embodiment includes an optical pickup 10a, a photo detector (PD) amplifier 21, a reproducing circuit 22, a CPU 24, and a recording device. A circuit 25, a laser drive circuit 26, a filter element drive circuit 27, a spindle motor 28, an integration circuit 31, a reference value storage circuit 32, a comparator 33, and a phase compensation servo circuit 34 are provided.

In the information recording / reproducing apparatus 2 according to the second embodiment, the optical pickup 10a includes a laser diode 11, a front monitor (FM) 12, a filter 13, a beam splitter 14, and an objective lens 15. The condenser lens 16 and the photo detector 17 are provided.

The front monitor 12 constitutes a specific example of the “monitoring means” of the present invention. For example, the front monitor 12 includes a light receiving sensor and the like, and the power of the light beam emitted from the laser diode 11 (ie, light This is the light intensity value or energy amount of the beam. The value according to the amount of received light) can be measured. The measured power is output to the integrating circuit 31.

Further, the integrating circuit 31 is configured to be able to integrate the power of the light beam measured by the front monitor 12. The power of the light beam integrated in the integration circuit 31 indicates a DC component of the light intensity of the light beam and is output to the comparator 33.

[0109] The reference value storage circuit 32 is configured to be able to output to the comparator 33 a reference value that is referred to when compared with the power of the light beam integrated in the integrating circuit. As a specific example of the reference value, “0” or “Vmax” indicating the maximum value of the light intensity of the light beam is stored, and these reference values are output to the comparator 33.

The comparator 33 compares the integrated value of the power of the light beam output from the integration circuit 31 with the reference value output from the reference value storage circuit 32, and the comparison result is input to the phase compensation servo circuit 34. Output.

[0111] More specifically, if the DC component of the light intensity of the light beam at time t (that is, the integrated value of the light intensity of the light beam) is V (t), then V (t + At +) -V (t ) Is compared with the reference value “0” or “Vma X”. Then, a comparison result indicating whether or not they match is output to the phase compensation servo circuit 34. This double, the integrated value of the reference value and the light intensity of the light beam may be configured to be output to the phase compensation servo circuit 34.

The phase compensation servo circuit 34 adjusts the timing (or phase) for changing the transmission amount of the filter 13 based on the comparison result in the comparator 33. More specifically, if the V (t + A t) -V (t) force matches the reference value “0” or “Vmax”, the timing for changing the transmission amount of the filter 13 is not changed. On the other hand, if V (t + At) -V (t) does not match the reference value "0" or "Vmax", V (t + At) — V (t) force reference value " The timing for changing the transmission amount of the filter 13 is changed so as to coincide with “0” or “Vmax”. The change in the timing of changing the amount of transmission of the filter 13 depends on how much difference there is between the V (t + At) -V (t) force reference value "0" or "Vmax". And are preferred.

As described above, according to the information recording / reproducing apparatus 2 in the second example, the rising and falling phases (or the tendency of increase / decrease or the optical beam in the change of the light intensity of the light beam). ONZOFF timing) and the rising and falling phases of the change in the transmission amount of the filter 13 (or the tendency of increase / decrease or the ON / OFF timing of the change in the transmission amount of the filter 13). ! / Thanks can be matched.

[0114] If the timing for changing the transmission amount of the filter 13 is not changed as in the second embodiment, as shown in FIG. 8 (a), the rise and fall of the change in the light intensity of the light beam is suppressed. There may be a case where the phase and the rising and falling phases in the change in the transmission amount of the filter 13 are shifted. In this case, the light intensity of the light beam actually irradiated onto the optical disc 50 changes with an inappropriate waveform lacking a part of the square wave as shown in FIG. 8 (b).

[0115] However, according to the second embodiment, by changing the timing of changing the transmission amount of the filter 13, as shown in Fig. 9 (a), the rise and rise in the change in the light intensity of the light beam. The falling phase and the phase of the rising and falling force S in the change in the transmission amount of the filter 13 can be aligned or matched. As a result, the light intensity of the light beam actually irradiated onto the optical disc 50 changes in an appropriate square wave shape as shown in FIG. 9 (b). As a result, according to the information recording / reproducing apparatus 2 in the second embodiment, the reliability of data recording on the optical disc 50 can be relatively improved in consideration of the above-described various benefits.

[0116] Furthermore, in the information recording / reproducing apparatus 2 that is useful in this embodiment, the CPU 24, the laser drive circuit 26, the filter element drive circuit 27, the integration circuit 31, the reference value storage circuit 32, the comparator 33, and the phase compensation servo The force described in the example in which the circuit 34 and the like are configured by a device separate from the optical pickup 10 may be configured so as to be integrated with the optical pickup 10 and further included in the laser diode 11. Needless to say.

In the above-described embodiment, the optical disc 50 and the recorder or player related to the optical disc 50 as an example of the information recording device or the information reproducing device have been described as an example of the information recording medium. The present invention is not limited to a player, and can be applied to other high-density recording or various information recording media compatible with a high transfer rate, as well as the recorder or player.

[0118] The present invention is not limited to the embodiments described above, but the entire claims and specification. The optical pickup device, the irradiation method, the information recording device, the information reproducing device, and the computer program that can be changed as appropriate without departing from the gist or idea of the invention that can be read. It is included in the scope. Industrial applicability

The optical pickup device, the irradiation method, the information recording device and the information reproducing device, and the computer program according to the present invention can be used for an optical pickup device used for recording and reproducing data on an information recording medium such as an optical disk. The present invention can be used for an information recording device and an information reproducing device including an optical pickup device. Further, the present invention can also be used for information recording devices and information reproducing devices that are mounted on or connectable to various computer devices for consumer use or business use.

Claims

The scope of the claims

[1] a light source that emits emitted light onto a recording surface of an information recording medium;

Light intensity control means for controlling the light source so as to change the light intensity of the emitted light into a substantially sinusoidal shape;

A finer disposed on the optical path of the outgoing light and changing a transmission amount of the outgoing outgoing light;

An optical pickup device comprising: filter control means for controlling the filter so as to change a transmission amount of the emitted light.

[2] The filter according to claim 1, wherein the filter control means controls the filter so as to change a transmission amount of the filter according to data recorded on the information recording medium. The optical pickup device described.

[3] The filter control means controls the filter so as to change a transmission amount of the filter in accordance with a strategy pulse corresponding to data recorded in the information recording medium. The optical pickup device according to item 1.

[4] The strategy pulse includes at least a first pulse having a predetermined first amplitude and a second pulse having a second amplitude smaller than the first amplitude,

The filter control means controls the filter so that a transmission amount of the filter according to the first pulse is larger than a transmission amount of the filter according to the second pulse. 4. An optical pickup device according to claim 3,

5. The light intensity control means controls the light source so as to change the light intensity of the emitted light according to data recorded on the information recording medium. The optical pickup device described.

6. The light intensity control means controls the light source so as to change the light intensity of the emitted light according to a strategy pulse corresponding to data recorded on the information recording medium. The optical pickup device according to item 1 of the range.

[7] The strategy pulse includes at least a first pulse having a predetermined first amplitude and a second pulse having a second amplitude smaller than the first amplitude,

The light intensity control means is configured such that the light intensity of the emitted light according to the first pulse is the first pulse. 7. The optical pickup device according to claim 6, wherein the light source is controlled to be greater than the light intensity of the emitted light corresponding to two pulses.

[8] The apparatus further comprises synchronization means for synchronizing each phase of rising and falling when the light intensity of the emitted light is increased and decreased and each phase of rising and falling when the transmission amount of the filter is changed. The optical pick-up device according to claim 1.

[9] It further comprises monitoring means for monitoring the light intensity of the emitted light that has passed through the filter,

9. The optical pick-up device according to claim 8, wherein the synchronization unit synchronizes the phase by comparing an integrated value of the monitored light intensity with a predetermined reference value.

[10] When the integrated value of the light intensity of the emitted light at time t is V (t), the synchronization means

10. The optical pickup device according to claim 9, wherein the phases are synchronized so that (t + At) —V (t) takes 0 or a maximum value.

[11] The filter is

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

An electrode for applying the voltage to the light absorption layer;

With

The filter control means controls the filter so as to change a transmission amount of the filter by changing a value of the voltage applied to the electrode. The optical pickup device according to Item.

[12] The filter is

A liquid crystal layer including a liquid crystal element whose molecular arrangement changes according to the value of the applied voltage; an electrode for applying the voltage to the liquid crystal layer;

With

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

[14] The optical pickup apparatus comprising: a light source that emits outgoing light onto a recording surface of an information recording medium; and a filter that is disposed on an optical path of the outgoing light and that changes a transmission amount of the incident outgoing light. A method of irradiating emitted light,

A light intensity control step of controlling the light source so as to change the light intensity of the emitted light into a substantially sinusoidal shape;

A filter control step of controlling the filter so as to change a transmission amount of the emitted light.

[15] a light source for irradiating the recording surface of the information recording medium with emitted light;

Filter control means for controlling the filter so as to change the transmission amount of the emitted light; and recording means for recording data on the information recording medium;

An information recording apparatus comprising:

[16] a light source for irradiating the recording surface of the information recording medium with emitted light;

Filter control means for controlling the filter so as to change the transmission amount of the emitted light; and reproduction means for reproducing data recorded on the information recording medium;

An information reproducing apparatus comprising:

[17] A light source that irradiates the recording surface of the information recording medium with the emitted light, and the light intensity of the emitted light is substantially positive. Light intensity control means for controlling the light source so as to change it into a chord wave shape, a filter disposed on the optical path of the outgoing light and for changing the transmission amount of the incident outgoing light, and the transmission amount of the outgoing light A computer program for recording control for controlling a computer provided in an information recording apparatus comprising filter control means for controlling the filter so as to change data and recording means for recording data on the information recording medium. The computer

A computer program that functions as at least part of the light intensity control means and the filter control means.

A light source for irradiating the recording surface of the information recording medium with the emitted light, a light intensity control means for controlling the light source so as to change the light intensity of the emitted light into a substantially sine wave shape, and an optical path of the emitted light A filter that is arranged and changes the transmission amount of the emitted light that is incident, filter control means that controls the filter so as to change the transmission amount of the emitted light, and data recorded on the information recording medium. A computer program for reproduction control for controlling a computer provided in an information reproduction apparatus comprising reproduction means for reproducing, wherein the computer is used as at least part of the light intensity control means and the filter control means. A computer program characterized by functioning.