JPH07129975A - Device for recording/reproducing information - Google Patents

Abstract

PURPOSE:To record and/or erase information with adequate power in both of a land part and a groove part without being affected by the gain fluctuation of focus error signals, the gain fluctuation of a track error signal and the light quantity fluctuation in the land part and the groove part. CONSTITUTION:In an information recording/reproducing device recording and/or reproducing the information for both of the land part and the groove part of a track provided on an information recording medium 35, a gain switching means 48 switching a gain of a focusing control means 41 in the land part and the groove part is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus for recording and / or reproducing and / or erasing information on an information recording medium such as an optical disk.

[0002]

2. Description of the Related Art In recent years, there has been a great demand for large capacity optical disk drive devices. In response to this, a method of recording information on both the land portion and the groove portion of the optical disc (hereinafter referred to as the land & groove recording method) has been proposed. In the land-and-groove recording method, light from a light source (not shown) is collimated by a collimator lens, and as shown in FIG.
Is irradiated.

The optical disk 13 has a recording film 15 formed on an optical disk substrate 14, and the optical disk substrate 15
The convex portions and the concave portions are formed in pairs, and since the recording film 15 is formed on the disk substrate 14, the convex portions 16 and the concave portions 17 are necessarily formed. A track is continuously formed by the convex portion 16 and the concave portion 17. The convex portion 16 is called a land portion, and the concave portion 17 is called a groove portion. The width L of the land portion 16 and the width G of the groove portion 17 usually take different values. The convex portion 16 and the concave portion 17 are the objective lens 12
By irradiating the light from the above to form the light spot 18, the recording pits 19 and 20 are formed and the information is recorded.

Conventionally, in an optical disk drive device, recording pits have been formed in only one of a land portion and a groove portion of an optical disk to record information. However, in the land-and-groove recording method, since information is recorded on both the land portion 16 and the groove portion 17 of the optical disc 13, the capacity of the optical disc 13 can be significantly increased. For example, when the land and groove recording method is adopted without changing the widths L and G of the land portion 16 and the groove portion 17, the capacity of the optical disc 13 is doubled.

In addition, in the Optical Data Strage '90, "High Track Density Magnet Optical Vertical Recording"
"Usirga Crosstalk Canceller" was announced, which is a land-and-groove crosstalk removal method. In this crosstalk removing method, in the land-and-groove recording method, a three-beam magneto-optical head irradiates three adjacent tracks on the optical disk with light and photoelectrically converts the reflected light into one main signal. Two sub-signals are obtained and these signals are input to the adaptive digital filter to obtain a crosstalk-free main signal.

[0006]

In order to realize the land-and-groove recording method, the light spot 18 must be formed at the proper focus position and track position for each of the land portion 16 and the groove portion 17. I won't.
That is, when recording and reproducing information on the land portion 16, proper focusing and tracking are performed on the land portion 16 by the focusing control system and the tracking control system, and information is recorded and recorded on the groove portion 17. When performing reproduction, it is necessary to perform appropriate focusing and tracking on the groove portion 17 by the focusing control system and the tracking control system.

Focusing and tracking are performed by a focusing control system and a tracking control system based on a focus error signal as shown in FIG. 8 and a track error signal as shown in FIG. FIG. 8 shows a focus error signal with respect to the defocus amount of the light spot 18. In FIG. 8, the solid line 21 shows the focus error signal when the spot 18 is located on the land portion 16, and the dotted line 22 shows the focus error signal when the spot 18 is located on the groove portion 17.

As is apparent from FIG. 8, the solid line 21 and the dotted line 2
The shape is different from 2. That is, in the land portion 16 and the groove portion 17, how the focus error signal is output (solid line 2
1, the slope of the dotted line 22) is different. The cause of this is the land part 1
6 and the groove portion 17 have different shapes and widths L and G. The difference in how the focus error signal is output between the land portion 16 and the groove portion 17 means that the gain of the focus error signal with respect to the focus error varies between the land portion 16 and the groove portion 17 from the viewpoint of the focusing control system. To do. This gain variation causes deterioration of the tracking stability of the focusing control system and an increase in steady-state deviation, and it is desirable to suppress it as much as possible.

FIG. 9 shows a track error signal with respect to the track error of the light spot 18 (deviation from the center of the target track). The slope of the track error signal (thick line portion 23) with respect to the track error at the center of the land portion 16 and the slope of the track error signal (thick line portion 24) with respect to the track error at the center of the groove portion 17 are:
The magnitude of the absolute value is different. This means that the gain of the track error signal with respect to the track error varies between the land portion 16 and the groove portion 17 from the viewpoint of the tracking control system. This variation in gain causes deterioration in tracking stability of the tracking control system and increases in steady-state deviation, and it is desirable to suppress it as much as possible.

FIG. 10 shows the amount of reflected light (amount of signal light) at the land 16 and the amount of reflected light (amount of signal light) at the glove portion 17. The amount of reflected light in the land portion 16 is larger than the amount of reflected light in the glove portion 17. This is a fluctuation in the amount of light seen from the signal detection system that detects the signal from the reflected light from the optical disc, which adversely affects the signal detection.

Further, the proper recording power (power of the light from the light source) for recording information on the recording film 15 of the optical disk 13 is influenced by the widths L and G of the land portion 16 or the groove portion 17. Generally, the larger the widths L and G, the larger. Therefore, unlike the proper recording power in the land portion 16 and the proper recording power in the groove portion 17, even if the information can be recorded in the proper recording power in either one of the land portion 16 and the groove portion 17, the other However, it is impossible to record information with an appropriate recording power. This also applies to the appropriate erasing power (power of light from the light source) when erasing information on the recording film 15 of the optical disc 13.

The present invention is not affected by the gain variation of the focus error signal between the land portion and the groove portion, the gain variation of the track error signal, and the variation of the light amount, and the information of appropriate power is obtained in both the land portion and the groove portion. It is an object to provide an information recording / reproducing device capable of recording and / or erasing.

[0013]

In order to achieve the above object, the invention according to claim 1 contemplates a light collecting means for collecting light from a light source on an information recording medium, and reflected light from the information recording medium. The information recording medium further includes a focus error signal generating unit that generates a signal corresponding to a focus error, and a focusing control unit that controls the focusing unit in the focusing direction by a signal from the focus error signal generating unit. In an information recording / reproducing apparatus for recording and / or reproducing information for both the land portion and the groove portion of the provided track, a gain for switching the gain of the focusing control means between the land portion and the groove portion. It is provided with a switching means.

According to a second aspect of the present invention, a focusing means for focusing the light from the light source on the information recording medium and a tracking error signal for generating a signal according to the tracking error from the reflected light from the information recording medium. Both a land portion and a groove portion of a track provided on the information recording medium, which have a generation means and a tracking control means for controlling the condensing means in a tracking direction by a signal from the tracking error signal generation means. An information recording / reproducing apparatus for recording and / or reproducing information is provided with gain switching means for switching the gain of the tracking control means between the land portion and the groove portion.

According to a third aspect of the present invention, there is provided light collecting means for collecting the light from the light source on the information recording medium, and reproduction signal detecting means for detecting the reproduction signal from the reflected light from the information recording medium. In the information recording / reproducing apparatus that records and / or reproduces information on both the land portion and the groove portion of the track provided on the information recording medium, the reproduction is performed by the land portion and the groove portion. A gain switching means for switching the gain of the signal detecting means is provided.

The invention according to claim 4 has a condensing means for condensing the light from the light source onto the information recording medium, and a reproduction signal detecting means for detecting a reproduction signal from the reflected light from the information recording medium. However, in an information recording / reproducing apparatus that records and / or reproduces information on both the land portion and the groove portion of the track provided on the information recording medium, during reproduction by the land portion and the groove portion. And a light emission intensity switching means for switching the light emission intensity of the light source.

According to a fifth aspect of the present invention, there is provided light collecting means for collecting the light from the light source on the information recording medium, and reproduction signal detecting means for detecting the reproduction signal from the reflected light from the information recording medium. However, in an information recording / reproducing apparatus that records and / or reproduces information on both the land portion and the groove portion of the track provided on the information recording medium, when recording on the land portion and the groove portion. And a light emission intensity switching means for switching the light emission intensity of the light source.

According to a sixth aspect of the present invention, there is provided light collecting means for collecting the light from the light source on the information recording medium, and reproduction signal detecting means for detecting the reproduction signal from the reflected light from the information recording medium. However, in an information recording / reproducing apparatus that records and / or reproduces information on both the land portion and the groove portion of the track provided on the information recording medium, when recording on the land portion and the groove portion. The light emitting pulse width switching means for switching the light emitting pulse width of the light source is provided.

According to a seventh aspect of the present invention, there is provided light collecting means for collecting the light from the light source on the information recording medium, and reproduction signal detecting means for detecting the reproduction signal from the reflected light from the information recording medium. However, in the information recording / reproducing apparatus for recording and / or reproducing and / or erasing information on both the land portion and the groove portion of the track provided on the information recording medium, the land portion and the groove portion And a light emission intensity switching means for switching the light emission intensity of the light source at the time of erasing.

[0020]

According to the first aspect of the invention, the gain of the focusing control means is switched by the gain switching means between the land portion and the groove portion. In the invention of claim 2, the gain of the tracking control means is switched by the gain switching means between the land portion and the groove portion. According to the third aspect of the invention, the gain of the reproduction signal detecting means is switched by the gain switching means between the land portion and the groove portion.

According to the fourth aspect of the present invention, the light emission intensity of the light source during reproduction is switched by the light emission intensity switching means between the land portion and the groove portion. According to the invention of claim 5,
The emission intensity of the light source during recording is switched by the emission intensity switching means between the land portion and the groove portion. In the invention according to claim 6, the emission pulse width of the light source at the time of recording is switched by the emission pulse width switching means between the land portion and the groove portion. In the invention according to claim 7, the emission intensity of the light source at the time of erasing is switched by the emission intensity switching means between the land portion and the groove portion.

[0022]

FIG. 1 shows a first embodiment of the present invention. This first
The embodiment is an embodiment of the invention described in claims 1, 2 and 3, and is a land & groove recording type information recording / reproducing apparatus for recording, reproducing and erasing information on a track on an optical disk. Light from a light source 31 made of a semiconductor laser is made into parallel light by a collimator lens 32, passes through a beam splitter 33, and a condenser means 3 made of an objective lens.
Information recording medium 3 formed of an optical disc that is focused by 4
It is irradiated to 5. The optical disc 35 is rotationally driven by a spindle motor (not shown), and the reflected light from the optical disc 35 passes through the objective lens 34 and the beam splitter 33 and is converted into a current voltage by a photodetector circuit 36 including a light receiving element. Similar to the above-mentioned optical disc 13, the optical disc 35 has a land portion and a groove portion formed by forming a recording film on an optical disc substrate and forming a convex portion and a concave portion in a pair on the optical disc substrate.

The signal detection circuit 37 detects the focus error signal 38 and the track error signal 3 from the output signal of the light detection circuit 36.
9. A reproduction signal (Rf signal) 40 is generated. The focusing control means 41 drives the focus actuator 42 in accordance with the focus error signal 38 from the signal detection circuit 37, and the focus actuator 42 causes the objective lens 3 to move.
4 is driven in the focusing direction (optical axis direction) to focus the light spot formed by the light from the objective lens 34 on the optical disc 35.

The tracking control means 43 drives the track actuator 44 in accordance with the track error signal 39 from the signal detection circuit 37, and the track actuator 44 moves the objective lens 34 in the tracking direction (direction crossing the track on the optical disk 35). It is driven so that the light spot on the optical disc 35 follows the track on the optical disc 35. The reproduced signal 40 from the signal detection circuit 37 is processed by the reproduced signal processing means 45.

The land portion / groove portion switching circuit 46 is a land portion / groove portion discriminating circuit for discriminating which of the land portion and the groove portion on the optical disc 35 is currently recording or reproducing information. , A signal 47 indicating whether the recording or reproduction of information is performed on the land portion or the groove portion on the optical disc 35. The focus gain switching circuit 48 adjusts the gain of the focusing control means 41 based on the output signal 47 of the land / groove switching circuit 46 so that the gain of the focus error signal 38 does not fluctuate between the land portion and the groove portion on the optical disc 35. Switch to.

Similarly, the track gain switching circuit 49
Is the output signal 4 of the land / groove switching circuit 46
7, the gain of the tracking control means 43 is switched so that the gain of the track error signal 39 does not change between the land portion and the groove portion on the optical disc 35, and the reproduction signal gain switching circuit 50 is a land portion / groove portion switching circuit. Based on the output signal 47 of 46, the gain of the signal detection circuit 37 (the gain of the reproduction signal generation portion) is switched so that the gain of the reproduction signal 40 does not change between the land portion and the groove portion on the optical disc 35.

FIG. 2 shows a focus gain switching circuit 48.
The configuration of the focusing control means 41 will be described in detail.
The focusing control means 41 is composed of a phase compensation circuit 51, an amplifier 52, and a current source 53, and the amplifier 52 is provided with an input resistor 54 and a feedback resistor 55. The focus gain switching circuit 48 includes a switch 56 and a resistor 57.
The resistor 57 is connected in parallel with the feedback resistor 55 via the switch 56.

The focus error signal 38 from the signal detection circuit 37 is phase-compensated by the phase compensation circuit 51, amplified by the amplifier 52, converted into a current by the current source 53, and supplied to the focus actuator 42.
The switch 56 is a land / groove switching circuit 46.
Is turned on / off by the output signal 47 to connect or open the resistor 57 in parallel with the feedback resistor 55, thereby switching the gain of the amplifier 52. Track gain switching circuit 49 and reproduction signal gain switching circuit 50
Is configured similarly to the focus gain switching circuit 48.

In the first embodiment, the focus gain switching circuit 48 switches the gain of the focusing control means 41 between the land portion and the groove portion, so that it is affected by the gain variation of the focus error signal between the land portion and the groove portion. Therefore, the tracking stability of the focusing control means 41 is not deteriorated and the steady-state deviation is not increased.
Further, since the gain of the tracking control means 43 is switched between the land portion and the groove portion by the track gain switching circuit 49, it is not affected by the gain variation of the track error signal between the land portion and the groove portion, and the tracking control means 43 follows the tracking. Stability deterioration and steady-state deviation increase are eliminated. Further, the reproduction signal gain switching circuit 50 switches the gain of the signal detection circuit 37 (the gain of the reproduction signal generation portion) between the land portion and the groove portion, so that the adverse effect on the signal detection due to the light amount variation between the land portion and the groove portion is caused. It can be lost.

FIG. 3 shows a second embodiment of the present invention. The second embodiment is an embodiment of the invention described in claim 4, and in the first embodiment, the reproduction signal gain switching circuit 50 is used.
The reproduction power switching circuit 58 is used in place of the above. The laser control means 59 controls the driving of the semiconductor laser 31, while the reproduction power switching circuit 58 reproduces the reproduction signal 40 based on the output signal 47 of the land / groove switching circuit 46 during reproduction of information from the optical disk 35. The level of the laser control means 59 is switched so that the level does not change between the land portion and the groove portion on the optical disc 35, and the reproduction power drive current of the semiconductor laser 31 is switched.

The reproduction power switching circuit 58 can be easily constructed by using the switch 56 and the like. The reproduction power switching circuit 58 switches the gain of the laser control means 59 to switch the reproduction power level of the semiconductor laser 31, and in the first embodiment, the reproduction signal gain switching circuit 50 causes the signal detection circuit 37.
Switching the gain (the gain of the reproduction signal generation portion) of (1) gives almost the same effect.

FIG. 4 shows a third embodiment of the present invention. The third embodiment is an embodiment of the invention described in claim 5, and the recording power switching circuit 60 is used in the second embodiment. The recording power switching circuit 60 is used for the optical disc 3
The semiconductor laser 31 is recorded on the basis of the output signal 47 of the land portion / groove portion switching circuit 46 at the time of recording the information.
The recording power of the semiconductor laser 31 is switched by switching the level of the laser control means 59 so that the recording power of (1) becomes an appropriate recording power in both the land portion and the groove portion on the optical disk 35. The recording power switching circuit 60 can be easily constructed by using the switch 56 and the like. In the third embodiment, the recording power switching circuit 60 switches the recording power of the semiconductor laser 31 between the land portion and the groove portion, so that information can be recorded with an appropriate power in both the land portion and the groove portion. .

FIG. 5 shows a fourth embodiment of the present invention. The fourth embodiment is an embodiment of the invention described in claim 6, and a recording pulse width switching circuit 61 is used in place of the recording power switching circuit 60 in the third embodiment. The laser control means 62 controls the drive of the semiconductor laser 31,
During recording, the semiconductor laser 31 is driven by a recording pulse signal to emit light. The recording pulse width switching circuit 61 is
At the time of recording, based on the output signal 47 of the land portion / groove portion switching circuit 46, the laser control means 62 is used so that the recording power of the semiconductor laser 31 becomes appropriate recording power in both the land portion and the groove portion on the optical disc 35. The emission pulse width of the semiconductor laser 31 is switched by controlling and switching the pulse width of the recording pulse signal. The recording pulse width switching circuit 61 can be easily constructed by using the switch 56 and the like.
In the fourth embodiment, since the light emission pulse width of the semiconductor laser 31 is switched by the recording pulse width switching circuit 61 between the land portion and the groove portion, it is necessary to record information with appropriate power in both the land portion and the groove portion. You can

FIG. 6 shows a fifth embodiment of the present invention. The fifth embodiment is an embodiment of the invention described in claim 7, and the erase power switching circuit 63 is used in the second embodiment. The erasing power switching circuit 63 is used for the optical disc 3
The semiconductor laser 3 is based on the output signal 47 of the land / groove switching circuit 46 when erasing the information on
The level of the laser control means 59 is switched so that the erasing power of 1 becomes an appropriate power in both the land portion and the groove portion on the optical disc 35. The erase power switching circuit 63 can be easily constructed by using the switch 56 and the like.

In the fifth embodiment, the erasing power switching circuit 63 switches the erasing power of the semiconductor laser 31 between the land portion and the groove portion, so that erasing can be performed with appropriate power in both the land portion and the groove portion. it can. The present invention is applicable to both cases where information recording and erasing are performed on the information recording medium in separate processes (when overwriting is not possible) and when information recording and erasing are performed at the same time (when overwriting is performed). Can be applied.

[0036]

As described above, according to the first aspect of the present invention, the focusing means for focusing the light from the light source on the information recording medium and the reflected light from the information recording medium according to the focus error. Track provided on the information recording medium, which has a focus error signal generating means for generating a signal and a focusing control means for controlling the focusing means in the focusing direction by a signal from the focus error signal generating means. In the information recording / reproducing apparatus for recording and / or reproducing the information for both the land portion and the groove portion, the gain switching means for switching the gain of the focusing control means between the land portion and the groove portion is provided. Therefore, it is not affected by the gain fluctuation of the focus error signal in the land part and the groove part, and the focusing control is suppressed. It is possible to eliminate an increase in the follow-up stability deterioration and steady-state error of the means.

According to the second aspect of the present invention, the light collecting means for collecting the light from the light source on the information recording medium, and the tracking for generating the signal according to the tracking error from the reflected light from the information recording medium. An error signal generating means and a tracking control means for controlling the light converging means in the tracking direction by a signal from the tracking error signal generating means, and a land portion and a groove portion of a track provided on the information recording medium. In the information recording / reproducing apparatus that records and / or reproduces information for both of the two, the land portion and the groove portion are provided with the gain switching means for switching the gain of the tracking control means. The tracking stability of the tracking control means is not affected by the gain fluctuation of the track error signal between It is possible to eliminate an increase in the degradation and steady-state error.

According to the third aspect of the present invention, the light collecting means for collecting the light from the light source on the information recording medium, and the reproduction signal detecting means for detecting the reproduction signal from the reflected light from the information recording medium. In the information recording / reproducing apparatus for recording and / or reproducing information on both the land portion and the groove portion of the track provided on the information recording medium, the land portion and the groove portion are Since the gain switching means for switching the gain of the reproduction signal detecting means is provided, it is possible to eliminate the adverse effect on the signal detection due to the light amount variation of the land portion and the groove portion.

According to the invention described in claim 4, light condensing means for condensing the light from the light source on the information recording medium, and reproduction signal detecting means for detecting the reproduction signal from the reflected light from the information recording medium. In the information recording / reproducing apparatus for recording and / or reproducing information on both the land portion and the groove portion of the track provided on the information recording medium, the land portion and the groove portion are Since the light emission intensity switching means for switching the light emission intensity of the light source at the time of reproduction is provided, it is possible to eliminate the adverse effect on the signal detection due to the light amount variation between the land portion and the groove portion.

According to the fifth aspect of the present invention, there is provided a condensing means for condensing the light from the light source on the information recording medium, and a reproduction signal detecting means for detecting the reproduction signal from the reflected light from the information recording medium. In the information recording / reproducing apparatus for recording and / or reproducing information on both the land portion and the groove portion of the track provided on the information recording medium, the land portion and the groove portion are Since the light emission intensity switching means for switching the light emission intensity of the light source at the time of recording is provided, it is possible to record information with an appropriate power in both the land portion and the groove portion.

According to the sixth aspect of the present invention, there is provided a condensing means for condensing the light from the light source on the information recording medium, and a reproduction signal detecting means for detecting a reproduction signal from the reflected light from the information recording medium. In the information recording / reproducing apparatus for recording and / or reproducing information on both the land portion and the groove portion of the track provided on the information recording medium, the land portion and the groove portion are Since the light emission pulse width switching means for switching the light emission pulse width of the light source at the time of recording is provided, it is possible to record information with an appropriate power in both the land portion and the groove portion.

According to the invention described in claim 7, there is provided a light collecting means for collecting the light from the light source on the information recording medium, and a reproduction signal detecting means for detecting the reproduction signal from the reflected light from the information recording medium. An information recording / reproducing apparatus for recording and / or reproducing and / or erasing information on both the land portion and the groove portion of the track provided on the information recording medium, Since the light emission intensity switching means for switching the light emission intensity of the light source at the time of erasing with the groove portion is provided, it is possible to perform erasing with appropriate power in both the land portion and the groove portion.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing in detail focusing control means and focus gain switching circuit of the first embodiment.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing a third embodiment of the present invention.

FIG. 5 is a block diagram showing a fourth embodiment of the present invention.

FIG. 6 is a block diagram showing a fifth embodiment of the present invention.

FIG. 7 is a diagram for explaining a land & groove recording method.

FIG. 8 is a diagram showing a focus error signal with respect to a focus error in the land & groove recording method.

FIG. 9 is a diagram showing a track error signal with respect to a track error of a land & groove recording system.

FIG. 10 is a diagram showing a relationship between a track position in the radial direction of an optical disc of a land & groove recording system and a reflected light amount.

[Explanation of symbols]

 37 signal detection circuit 41 focusing control means 43 tracking control means 46 land / groove switching circuit 48 focus gain switching circuit 49 track gain switching circuit 50 reproduction signal gain switching circuit 58 reproduction power switching circuit 59, 62 laser control means 60 recording power Switching circuit 61 Recording pulse width switching circuit 63 Erase power switching circuit

Claims (7)

[Claims] 1. A focusing means for focusing light from a light source on an information recording medium, a focus error signal generating means for generating a signal according to a focus error from reflected light from the information recording medium, and the focus. Focusing control means for controlling the focusing means in the focusing direction by a signal from the error signal generating means, and recording information on both the land portion and the groove portion of the track provided on the information recording medium. An information recording / reproducing apparatus for performing reproduction and / or reproduction, comprising gain switching means for switching the gain of the focusing control means between the land portion and the groove portion. 2. Condensing means for condensing light from a light source onto an information recording medium, tracking error signal generating means for generating a signal according to a tracking error from reflected light from the information recording medium, and this tracking And a tracking control means for controlling the focusing means in the tracking direction by a signal from the error signal generating means, and recording information on both the land portion and the groove portion of the track provided on the information recording medium. And / or information recording / playback
An information recording / reproducing apparatus, wherein the reproducing apparatus includes a gain switching unit that switches a gain of the tracking control unit between the land portion and the groove portion. 3. An information recording medium, comprising: light collecting means for collecting light from a light source on an information recording medium; and reproduction signal detecting means for detecting a reproduction signal from reflected light from the information recording medium. In an information recording / reproducing apparatus that records and / or reproduces information on both the land portion and the groove portion of the track provided on the track, the gain of the reproduction signal detecting means is set between the land portion and the groove portion. An information recording / reproducing apparatus comprising a gain switching means for switching. 4. An information recording medium, comprising: a condensing means for condensing light from a light source onto an information recording medium, and a reproduction signal detecting means for detecting a reproduction signal from reflected light from the information recording medium. In an information recording / reproducing apparatus which records and / or reproduces information on both the land portion and the groove portion of the track provided in the track, the light emission intensity of the light source at the time of reproduction by the land portion and the groove portion. An information recording / reproducing apparatus comprising a light emission intensity switching means for switching between. 5. The information recording medium, comprising: a condensing means for condensing light from a light source onto an information recording medium, and a reproduction signal detecting means for detecting a reproduction signal from reflected light from the information recording medium. In an information recording / reproducing apparatus that records and / or reproduces information on both the land portion and the groove portion of the track provided in the track, the light emission intensity of the light source at the time of recording by the land portion and the groove portion. An information recording / reproducing apparatus comprising a light emission intensity switching means for switching between. 6. An information recording medium, comprising: light collecting means for collecting light from a light source on an information recording medium, and reproduction signal detecting means for detecting a reproduction signal from reflected light from the information recording medium. In an information recording / reproducing apparatus for recording and / or reproducing information to / from both the land portion and the groove portion of the track provided in, the light emission pulse of the light source at the time of recording at the land portion and the groove portion An information recording / reproducing apparatus comprising a light emission pulse width switching means for switching the width. 7. An information recording medium, comprising: a condensing means for condensing light from a light source onto an information recording medium, and a reproduction signal detecting means for detecting a reproduction signal from reflected light from the information recording medium. In an information recording / reproducing apparatus for recording and / or reproducing and / or erasing information with respect to both the land portion and the groove portion of the track provided in the above, in the erasing with the land portion and the groove portion, An information recording / reproducing apparatus comprising a light emission intensity switching means for switching the light emission intensity of a light source.