JP2002222526A - Recording and reproducing device of optical information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a satisfactorily recordable recording/reproducing device of optical information in the recording/reproducing device for three-dimensionally recording an information bit. SOLUTION: The recording/reproducing device of the optical information is provided with a light source 1, an objective lens 4 for converging a light 2 emitted from the light source 1 to an information recording medium 11 and a photodetector 10 for detecting the light from an information recording medium 11, and the information bit is three-dimensionally recorded in a recording member 11b of the information recording medium 11 by utilizing the change of an optical constant of the recording member 11b. Also, for the recording/ reproducing device, the thickness of the recording member 11b is thicker than a wavelength of the light, and the information bit is three-dimensionally recorded successively in the recording member 11b in such order that a converged light 7 of the objective lens 4 does not pass through the already recorded information bit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing apparatus for recording information bits three-dimensionally, and more particularly to an optical information recording / reproducing apparatus capable of recording information bits satisfactorily.

[0002]

2. Description of the Related Art A conventional optical information recording / reproducing apparatus for recording information bits three-dimensionally is disclosed in JP-A-6-28672. FIG. 8 shows a conventional optical information recording / reproducing apparatus.
Shown in In the information recording method of this apparatus, the light 102 emitted from the light source 101 is irradiated by the objective lens 114 onto the information recording medium 111 composed of a recording member such as a photopolymer having a thickness larger than the wavelength of light (convergent light 107). The light spot is recorded as information bits 105. This information bit is caused by a change in the refractive index, and the size in the x, y, and z axis directions is generally larger than the wavelength of light in any direction.

[0003] In addition, the information bit 105 is similarly condensed with low power, and the convergent light 107 is detected by the photodetector 110 via the objective lens 114 and the beam splitter 113 to reproduce a signal. I can do it. In order to increase the information capacity, information bits 105 are three-dimensionally recorded on the information recording medium 111 in the optical axis direction (z-axis direction) of the objective lens 114 as shown in FIG.

[0004]

However, in the conventional optical information recording / reproducing apparatus for recording information bits three-dimensionally, when information is recorded, the convergent light 107 of the objective lens is recorded.
When passing through the information bit 116 already recorded, the convergent light 107 is affected by the information bit 116 and causes an aberration, which makes it difficult to converge satisfactorily at the focus, and the information bit 105 to be recorded from now on is blurred. The present inventors have found that there is a problem that the data is lost. Aberration occurs because
This is considered to be because the information bit 116 is thicker than the wavelength of the light, so that the light is mainly refracted in that region.

The present invention has been made to solve the above-mentioned problems in the prior art, and relates to an optical information recording / reproducing apparatus for recording information bits three-dimensionally. It is intended to provide a device.

[0006]

To solve the above-mentioned problems, an optical information recording / reproducing apparatus according to the present invention has the following arrangement.

According to a first optical information recording / reproducing apparatus of the present invention, in an information recording medium including a recording member on which information bits are recorded, information bits are three-dimensionally converted by utilizing a change in an optical constant of the recording member. This is an optical information recording / reproducing apparatus for recording. The optical information recording / reproducing apparatus includes a light source, an objective lens for condensing light emitted from the light source on an information recording medium, and a photodetector for detecting light from the information recording medium. The thickness of the recording member is greater than the wavelength of light from the light source. The optical information recording / reproducing apparatus sequentially records information bits three-dimensionally in a recording member so that convergent light from the objective lens does not pass through already recorded information bits.

In the above optical information recording / reproducing apparatus, information bits may be sequentially recorded from a position in the recording member farthest from the objective lens.

The objective lens is a lens having a numerical aperture of 0.7 or more. A pinhole is disposed in an optical path including the objective lens and the photodetector, and light from an information recording medium is transmitted through the pinhole. After that, detection may be performed by a photodetector.

In the optical information recording / reproducing apparatus, a focus / track error signal detecting element which is a branch optical element and a pinhole array having a plurality of pinholes are arranged on an optical path including an objective lens and a photodetector. May be. At this time, the light from the information recording medium is split into a plurality of lights by the focus / track error signal detection element, and transmitted through the respective pinholes corresponding to the plurality of lights of the pinhole array, and then transmitted by the photodetector. You may make it detect.

Further, the optical information recording / reproducing apparatus may further include a focus / track error signal detecting element which is a branch optical element on an optical path including the objective lens and the photodetector. At this time, the light from the information recording medium may be split into a plurality of lights by a focus / track error signal detecting element, and the split lights may be respectively detected by a photodetector having an area smaller than each of the split lights. .

Further, the optical information recording / reproducing apparatus includes a focus / track error signal detecting element which is a branch optical element and a pinhole array having a plurality of pinholes on an optical path including an objective lens and a photodetector. It may be arranged. At this time, the light from the information recording medium is split into a plurality of lights by the focus / track error signal detecting element, and the split light corresponding to the track error signal is transmitted through the pinholes of the pinhole array, and then the photodetector is turned on. The detection may be performed by using.

The wavelength λ of the light emitted from the light source is 0.35
The optical system that substantially satisfies μm ≦ λ ≦ 0.45 μm and includes the objective lens may have an achromatic configuration.

Further, the optical information recording / reproducing apparatus may further include a spherical aberration correction element in an optical path including a light source and an objective lens. The spherical aberration correction element may control the amount of spherical aberration according to the recording depth of the information bit recorded in the recording member.

[0015] The optical constant may be a refractive index. At this time, the change in the refractive index is preferably 0.005 or more.

[0016] The information recording medium may be composed of only a single recording member. Further, the information recording medium may include a recording member and a substrate. Or, the information recording medium is
The recording member may be configured to be sandwiched between the substrate and the protection medium.

[0017] The photodetector may be an avalanche photodiode (APD).

The optical information recording / reproducing apparatus may further include a condenser lens on the opposite side of the information recording medium from the objective lens. At this time, light from the information recording medium is condensed on a photodetector by a condenser lens and detected. The optical information recording / reproducing device may control the focus position of the objective lens based on the interface of the recording member of the information recording medium.

According to a second optical information recording / reproducing apparatus of the present invention, in an information recording medium including a recording member on which information bits are recorded, information bits are three-dimensionally converted by utilizing a change in the refractive index of the recording member. This is an optical information recording / reproducing apparatus for recording. The optical information recording / reproducing apparatus includes a light source, an objective lens for condensing light emitted from the light source on an information recording medium, and a photodetector for detecting light from the information recording medium. The thickness of the recording member is greater than the wavelength of light from the light source, and the amount of change in the refractive index is 0.02 or less. The optical information recording / reproducing device is
The information bits are sequentially and three-dimensionally recorded in the recording member so that the number of columns of the recorded information bits through which the convergent light from the objective lens passes is four or less in the optical axis direction.

[0020]

(Embodiment 1) First, an optical information recording / reproducing apparatus according to Embodiment 1 of the present invention will be described in detail with reference to FIG. 1 to FIG.

FIG. 1 is a side view showing the basic structure of an optical head of an optical information recording / reproducing apparatus according to Embodiment 1 of the present invention and the state of light propagation. FIG. 2 is a side view showing the optical information recording / reproducing apparatus of the embodiment. FIG. 3 and FIG. 4 are diagrams illustrating a state in which a signal is recorded on an information recording medium. FIGS. FIG. 5 is an explanatory diagram showing a state where a signal is recorded on an information recording medium having another configuration of the optical information recording / reproducing apparatus of the embodiment.

As shown in FIG. 1, in the optical head of the optical information recording / reproducing apparatus of the present embodiment, a beam splitter 1 is provided in an optical path from a light source 1 to an information recording medium 11.
3, a collimator lens 3, a focus / track error signal detecting element 8, a rising mirror 12, a spherical aberration correcting element 9, and an objective lens 4 (set lens 4a, 4b). The light source 1 is, for example, a semiconductor laser light source having a wavelength of 0.405 μm. The laser light 2 emitted from the light source 1 in the y-axis direction is converted into substantially parallel light 6 by a collimator lens 3, and a diffraction-type focus / track error signal is generated. Detection element 8
Is transmitted (using the 0th-order diffracted light), and the optical path is bent in the z-axis direction by the rising mirror 12. Then, the laser beam 6 bent in the z-axis direction passes through the spherical aberration correction element 9 and is passed through the objective lens 4 to the information recording medium 11.
The light is converged (converged light 7) on the upper side.

The laser beam 7 reflected by the information recording medium 11 is turned in the opposite direction, passes through the objective lens 4, the spherical aberration correcting element 9 and the rising mirror 12 in this order, and is turned into the diffraction type focus / track error signal detecting element 8 (Using the first-order diffracted light, however, in FIG. 1, for simplicity, the split light is not shown in the optical path from the diffraction type focus / track error signal detection element 8 to the beam splitter 13) . The split light is converged by the collimator lens 3 and further split by the beam splitter 13.
Is deflected in the −z-axis direction. Multiple branch lights 17a-
The signal 17c is transmitted through each of the pinholes 14a to 14c of the pinhole array 14 provided with a plurality of pinholes, and signals are detected by the photodetectors 10a, 10b, and 10c in an array. From these detection signals, a reproduction signal and a focus error signal and a track error signal, which are servo signals, are read. From the reproduced signal, the optical information recording medium 1
The signal recorded in No. 1 is read. By detecting a plurality of lights branched by the focus / track erroneous signal detection element 8, which is a branch optical element, by the photodetectors 10a, 10b, and 10c, a focus error signal and a track error signal other than the reproduction signal are generated. . From each of the generated error signals, it is determined whether the focus position (z-direction position) and the track position (x or y-direction position) of the objective lens 4 with respect to the optical information recording medium 11 are optimal. If the position is deviated from the optimal position, the objective lens 4 is driven to the optimal position by an actuator (not shown) attached to the objective lens 4. At this time, the information recording medium 11 is used as a reference of the position for controlling the focus.
By using the interface of the recording member 11b, the focus position of the objective lens 4 can be accurately controlled.
The interface between the recording member 11b and the substrate 11a
b or the surface of the recording member 11b facing the objective lens 4a.

Although the pinhole array 14 is installed at a position substantially at the focal point of the split light 17, it is also possible to place a separate pinhole at a position corresponding to the focus of the split light 17. By making the size of the pinhole smaller than each convergent light 17 (not shown), only the light at the center of the convergent light 17 is detected. By doing so, the convergent light 1
Unnecessary high-order aberration light distributed around the periphery of 7 can be removed, and not only the reproduction signal but also the S / N of the servo error signal can be improved. At this time, since the peripheral light of the branched light 17 is deleted, the light amount is reduced. Therefore, the signal intensity can be increased by using an APD (avalanche photodiode). In a recording / reproducing apparatus for recording information bits three-dimensionally, it is effective to use such an APD since the amount of detected light cannot be increased due to material limitations.

Further, instead of the pinhole array 14,
The photodetector 10 having an area smaller than each branch light 17
Thus, the same effect can be obtained even if the branch light 17 is detected. Further, only the branch lights 17b and 17c corresponding to the track error signal are supplied to the pinhole array 14.
Through the pinholes 14b and 14c of the photodetector 10
The branch light 17a detected by b and 10c and corresponding to the focus error signal may be directly detected by, for example, a four-divided photodetector 10a without passing through a pinhole. In such an arrangement, for example, an astigmatism method can be used as the focus detection method. If the area of the photodetector 10a at this time is smaller than the cross-sectional area of the branched light 17a at the detection position, higher-order aberration components can be reduced.

In the present embodiment, the objective lens 4 is a pair of lenses 4a and 4b, and the numerical aperture NA is increased to 0.7 or more (for example, 0.85). By increasing the numerical aperture, there is an effect that the recording density in the plane (xy plane) is increased, and the interval between the bits 5 in the z direction is narrowed, so that the density can be increased. Further, as the information recording medium 11, for example, a substrate 11a having a thickness of, for example, 600 μm is used in combination with a recording member 11b which is thicker than the wavelength, for example, about several tens to several hundreds of μm, and the substrate is, for example, polycarbonate. However, resins such as PMMA, glass and the like are also useful. Further, as the recording member 11b, any material can be used as long as the optical constant such as the refractive index changes according to the light intensity. For example, a photopolymer, an organic dye, Li
A photorefractive crystal such as NbO3, a multi-photon absorption material such as bichromium gelatin, diallyl ethene, and the like are useful. In the present embodiment, for example, a photopolymer is used and the refractive index is increased by light irradiation.

As shown in FIG. 2, the surface of the recording member 11b formed on the substrate 11a has a bare structure without a protective layer. However, the recording member 11b is sufficiently thicker than the wavelength, and the surface is used as a protective layer. The cost can be reduced by such a simple configuration. Further, as shown in FIG. 5, the recording member 11b further has a thickness of several tens to ten.
By combining another protective medium such as a resin film of several hundred μm into a sandwich structure, the environmental resistance and surface accuracy of the information recording medium 11 are further improved.

As shown in FIG. 2, by irradiating the recording member 11b of the information recording medium 11 with the convergent light 7, the refractive index at the focal point increases, and the information bit 5 is recorded (FIG. 2).
In this embodiment, only the recorded information bits are described in gray.) In the present embodiment, however, the convergent light 7 of the objective lens 4 is provided in the recording member 11b so as not to pass the already recorded information bits. , The information bits are sequentially recorded three-dimensionally.

More specifically, the above-described recording can be realized by sequentially recording information bits from a position farthest from the objective lens 4 in the recording member 11b. In the configuration of FIG. 2, it is sufficient to record three-dimensionally in the −z-axis direction, such as a row 15a, a row 15b, and a row 15c. At this time, since the thickness of the recording member 11b through which the convergent light passes varies depending on the recording depth, the light from the light source 1 to the objective lens 4
If the information is recorded while controlling the amount of spherical aberration according to the recording depth of the information bit 5 to be recorded in the recording member 11b by the spherical aberration correction element 9 provided in the optical path up to Can be formed. Spherical aberration correction element 9
Can be configured by a liquid crystal element having a variable refractive index distribution or a beam expander having a variable length in the optical axis direction by an actuator.

When recording in the unrecorded portion of the information bit shown in FIG. 2, the recording direction for suppressing the amount of aberration generation is such that the convergent light 7 does not pass through the already recorded information bit. It does not necessarily have to be in the −z axis direction.

Next, the recording member 11b of the information recording medium 11
The relationship between the magnitude of the refractive index of the information bit to be recorded in the optical disc and the degree of occurrence of the aberration of the convergent light 7 will be described. As shown in FIG. 3, the information bit string 15a to be recorded or read is located on the near side (−z direction) in the z-axis direction, for example, 15b to 15b.
Let us consider a case where the information bits 5 in the four columns of e have already been recorded. FIG. 3A shows a case where the refractive index change Δn of the refraction sphere serving as the information bit 5 is 0 (corresponding to unrecorded), and the convergent light 7 is well focused. However, as shown in FIGS. 3B, 3C, and 4A to 4D, the refractive index change Δ
As the magnitude of n increases, the spread of the light beam at the focal point increases. Increasing the spread at the focal point results in so-called defocusing, which requires recording power at the time of recording, increases the size of recording information bits, and degrades writing characteristics. At the time of reproduction, the S / N of the read signal is reduced and the quality is degraded. As described above, a higher-order aberration component is taken by the pinhole provided in front of the photodetector. With such a configuration, it is possible to prevent the reproduction signal from lowering.

As explained above, the present inventor:
If the information bits are sequentially and three-dimensionally recorded in the recording member 11b in such an order that the convergent light 7 of the objective lens 4 does not pass through the already recorded information bits, the phenomenon of defocus does not occur. We found that we could do better. Further, the present inventor has found that the change amount Δn of the refractive index of the refractive sphere 5 as the information bit is 0.02 or less and the objective lens 4
The information bits are sequentially and three-dimensionally recorded in the recording member 11b such that the number of columns of the recorded information bits through which the convergent light 7 from the laser beam passes becomes four or less in the optical axis direction (z-axis direction). If so, it has been found that the phenomenon of defocus during writing is within an allowable range. This corresponds to Δ in FIG.
At n = 0.02, the reason can be explained from the fact that the light beam at the focal point does not impinge on the adjacent refraction sphere.

When the magnitude of Δn decreases, the occurrence of aberration is suppressed, but the amount of detected light decreases. The present inventors have found that when Δn is 0.005 or more, the S / N almost falls within a problem-free range. Also in this case, it is desirable that the photodetector is an APD.

(Embodiment 2) Next, an optical information recording / reproducing apparatus according to Embodiment 2 of the present invention will be described with reference to FIG.
The following description focuses on differences from the first embodiment. FIG. 6 is an explanatory diagram showing a state where a signal is recorded on an information recording medium of the optical information recording / reproducing apparatus according to Embodiment 2 of the present invention.

The optical information recording / reproducing apparatus of the present embodiment
The wavelength λ of the light emitted from the light source is 0.35 μm ≦ λ ≦
The optical system that substantially satisfies 0.45 μm and includes the objective lens 4 has an achromatic configuration. In particular, when the wavelength is in this range, since the material dispersion of the optical system is large, good optical characteristics can be obtained by the achromatic structure. In the present embodiment, the objective lens 4 has an achromatic structure with a set of three convex and concave portions of 4a to 4c. However, this is achieved by using a collimator lens of two sets of convex and concave portions or a set of three convex and concave portions. Alternatively, it is also possible to achromatize with another optical system. Further, the information recording medium 11 is composed of only the recording member 11b and has a simple structure, which is advantageous in cost.

Third Embodiment Next, an optical information recording / reproducing apparatus according to a third embodiment of the present invention will be described with reference to FIG.
The following description focuses on differences from the first embodiment. FIG. 7 is a side view showing a basic configuration of an optical information recording / reproducing apparatus according to Embodiment 3 of the present invention and a state of light propagation. In the present embodiment, as shown in FIG. 7, a configuration using a transmission type information recording medium 11 is employed.

The convergent light 7 from the objective lens 4 is condensed on a transmission type information recording medium 11, and a signal is written or read out, and the converging light 7 is provided on the opposite side of the information recording medium 11 from the objective lens 4. The light is condensed by an optical lens 16 and detected by a photodetector 10 via a focus / track error signal detecting element 8 and a pinhole array 14.

By adopting the transmission type configuration, the convergent light 7
Pass through the recording member 11b once (Embodiment 1)
(2 times in the reflection type optical information recording / reproducing apparatus), the occurrence of aberration from already recorded information bits is about half of that in the case of reflection detection, and the quality of signal reading is the same as that of the first embodiment. It is better than a reflection type optical information recording / reproducing device.

Although the optical information recording / reproducing apparatuses according to the first to third embodiments have been described above, the present invention is not limited to these embodiments, and the optical information recording / reproducing apparatus according to each of the embodiments is not limited thereto. The present invention also includes an optical information recording / reproducing apparatus in which the configuration of the recording / reproducing apparatus is combined, and can achieve the same effect. The optical information recording / reproducing apparatus includes a rewritable type in addition to a write-once type. Note that the objective lens and the collimator lens used in the above embodiment are named for convenience, and are the same as generally used lenses.

In the above embodiment, an optical disk has been described as an example. However, a similar information recording / reproducing apparatus is designed so as to be able to reproduce a plurality of media having different specifications such as thickness and recording density. Card or drum,
Application to a tape-shaped product is also included in the scope of the present invention.

[0041]

As described above, according to the present invention,
Regarding an optical information recording / reproducing apparatus for recording information bits three-dimensionally, the convergent light of the objective lens does not irradiate the already recorded information bits, so that there is no occurrence of optical aberration and optical information recording that can be recorded well. A playback device can be realized.

[Brief description of the drawings]

FIG. 1 is a side view showing a basic configuration of an optical head of an optical information recording / reproducing apparatus according to a first embodiment of the present invention and a state of light propagation.

FIG. 2 is an explanatory diagram showing a state of recording a signal on an information recording medium of the optical information recording / reproducing apparatus according to the first embodiment of the present invention.

FIG. 3 is a ray tracing diagram when the magnitude of the refractive index of information bits recorded on an information recording medium of the optical information recording / reproducing apparatus according to Embodiment 1 of the present invention is changed.

FIG. 4 is a ray tracing diagram when the magnitude of the refractive index of information bits recorded on an information recording medium of the optical information recording / reproducing apparatus according to Embodiment 1 of the present invention is changed.

FIG. 5 is an explanatory diagram showing a state in which a signal is recorded on an information recording medium having another configuration of the optical information recording / reproducing apparatus according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram showing a state of recording a signal on an information recording medium of the optical information recording / reproducing apparatus according to the second embodiment of the present invention.

FIG. 7 is a side view showing a basic configuration of an optical head of an optical information recording / reproducing apparatus according to Embodiment 3 of the present invention and a state of light propagation.

FIG. 8 is a diagram showing a conventional optical information recording / reproducing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Light source 2 Emitted light 3 Collimator lens 4 Objective lens 5 Information bit 6 Parallel light 7 Convergent light 8 Focus / track error signal detection element 9 Spherical aberration correction element 10 Photodetector 11 Information recording medium (11a: substrate, 11b: recording member) , 11c: protection medium) 12 Establishing mirror 13 Beam splitter 14 Pinhole array (14a to 14c: pinhole) 15 Recorded information bit string 16 Condensing lens 17 Branch light

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tetsuo Hosomi 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 5D090 BB12 BB17 CC12 CC14 DD01 DD05 GG11 LL01 5D118 BB08 CA11 CD02 CD03 DA16 DA33 DA43 5D119 AA22 BB13 EC01 JA04 JA09 JA24 JA43 JA70 JB02 KA02

Claims (17)

[Claims] 1. An optical information recording / reproducing apparatus for three-dimensionally recording information bits by using a change in an optical constant of the recording member in an information recording medium including a recording member on which information bits are recorded, comprising: An objective lens for condensing light emitted from the light source on an information recording medium; and a photodetector for detecting light from the information recording medium, wherein the thickness of the recording member is equal to the light from the light source. An optical information recording / reproducing apparatus for sequentially recording the information bits three-dimensionally in the recording member so that the convergent light from the objective lens does not pass through the already recorded information bits. 2. The optical information recording / reproducing apparatus according to claim 1, wherein information bits are sequentially recorded from a position of the recording member farthest from the objective lens. 3. The optical information recording / reproducing apparatus according to claim 1, wherein the optical constant is a refractive index. 4. The optical information recording / reproducing apparatus according to claim 3, wherein the amount of change in the refractive index is 0.005 or more. 5. An optical information recording / reproducing apparatus for three-dimensionally recording information bits by using a change in a refractive index of the recording member in an information recording medium including a recording member on which information bits are recorded, comprising: And an objective lens for condensing light emitted from the light source on an information recording medium; and a photodetector for detecting light from the information recording medium, wherein the thickness of the recording member is equal to the light from the light source. And the amount of change in the refractive index is 0.02 or less, and the number of columns of recorded information bits through which convergent light from the objective lens passes is four or less in the optical axis direction. An optical information recording / reproducing apparatus for sequentially recording the information bits three-dimensionally in a recording member. 6. The objective lens is a lens having a numerical aperture of 0.7 or more, a pinhole is arranged in an optical path including the objective lens and the photodetector, and light from an information recording medium is transmitted to the pinhole. 6. The optical information recording / reproducing apparatus according to claim 1, wherein the optical information is detected by the photodetector after transmitting light. 7. An information recording medium, comprising: a focus / track error signal detection element, which is a branching optical element, and a pinhole array having a plurality of pinholes, in an optical path including the objective lens and the photodetector. Is split into a plurality of lights by the focus / track error signal detection element, and the split light is transmitted through respective pinholes corresponding to the split light in the pinhole array, and then is split by the photodetector. The optical information recording / reproducing device according to claim 1, wherein the optical information recording / reproducing device detects. 8. A focus / track error signal detecting element, which is a branch optical element, is further disposed on an optical path including the objective lens and the photodetector, and detects light from an information recording medium by using the focus / track error signal detecting element. 6. The optical information recording / reproducing apparatus according to claim 1, wherein the light is split into a plurality of lights, and each of the split lights is detected by a photodetector having an area smaller than each of the split lights. 9. A focus / track error signal detection element, which is a branching optical element, and a pinhole array having a plurality of pinholes are arranged in an optical path including an objective lens and a photodetector. The light is split into a plurality of lights by the focus / track error signal detecting element, and the split light corresponding to the track error signal among the split lights is transmitted through the pinholes of the pinhole array. The optical information recording apparatus according to claim 1, wherein the optical information is detected by a detector. 10. The wavelength λ of light emitted from a light source is 0.1.
The optical information recording apparatus according to claim 1, wherein the optical system substantially satisfies 35 μm ≦ λ ≦ 0.45 μm, and the optical system including the objective lens has an achromatic configuration. 11. A spherical aberration correction element is further disposed in an optical path including the light source and the objective lens, and the spherical aberration correction element has a spherical surface according to a recording depth of information bits recorded in the recording member. The optical information recording / reproducing device according to claim 1, wherein the aberration information is controlled. 12. The optical information recording / reproducing apparatus according to claim 1, wherein the information recording medium comprises only a single recording member. 13. The optical information recording / reproducing apparatus according to claim 1, wherein the information recording medium comprises a recording member and a substrate. 14. The information recording medium according to claim 1, wherein a recording member is sandwiched between a substrate and a protection medium.
An optical information recording / reproducing apparatus according to claim 1. 15. The optical information recording / reproducing apparatus according to claim 1, wherein the photodetector comprises an avalanche photodiode. 16. A condenser lens is disposed on the opposite side of the information recording medium from the objective lens, and the light from the information recording medium is condensed on a photodetector by the condenser lens and detected. The optical information recording / reproducing device according to claim 1 or 5. 17. A focus position of the objective lens is controlled with reference to an interface of a recording member of the information recording medium.
The optical information recording / reproducing device according to claim 1 or 5.