JPH10208277A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup device capable of surely keeping compatibility of optical disks different in substrate thickness without deteriorating recording/reproducing signals. SOLUTION: A semi-reflection film 51 reflects a part of luminous flux made incident from a polarizing beam splitter 42 through a 1/4 wavelength plate 44 and transmits a part through. An objective lens 47 irradiates the luminous flux reflected by the semi-reflection film 51 and transmitting through the 1/4 wavelength plate 44 on an optical information recording medium 52 as a minute spot. A total reflection mirror 45 imparts aberration to the luminous flux reflected on the semi-reflection film 51, and converts it to the luminous flux becoming the minute spot on the optical information recording medium 48 to reflect it toward the objective lens 47 side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical pickup device for writing and / or reading information signals to / from an optical disk as an information recording medium.

[0002]

2. Description of the Related Art FIG. 15 shows a configuration of a reproducing system of a conventional optical pickup device in an optical information recording / reproducing apparatus which recognizes a signal recorded on a medium by a change in reflectance. This optical pickup device includes a laser diode 31, a collimator lens 33, a polarizing beam splitter 32, a λ /
It comprises four plates 34, an objective lens 35, a multi-lens (detection lens) 37, and a photodiode 38 as a photodetector.

[0003] A linearly-polarized diffused light beam emitted by a laser diode 31 passes through a collimator lens 33 to become a parallel light beam, passes through a polarizing beam splitter 32, and enters a λ / 4 plate 34. Thereafter, the light is converted into circularly polarized light by the λ / 4 plate 34, enters the objective lens 35, and is condensed on the optical disk 36 by the objective lens 35. The collected light undergoes intensity modulation on the optical disk 36, is reflected, passes through the objective lens 35 and the λ / 4 plate 34 again to be linearly polarized, and is reflected at right angles by the polarization beam splitter 32. Then, the light passes through the multi-lens 37 and enters a photodiode 38 which is a photodetector. In the photodiode 38, information of incident light is converted into an electric signal to become a focus error signal and a tracking error signal. It is used as a reference for correction.

[0004]

In recent years, the density of optical disks as package media for computer recording devices, music, image information, and the like has been increasing. As one method of increasing the density of an optical disc, a technique of increasing the numerical aperture (NA) of an objective lens compared to a conventional one (higher NA)
There is. However, when the numerical aperture (NA) of the objective lens is increased, the skew amount θ and the substrate thickness t of the optical disc are increased.
Coma aberration proportional to the product of Therefore, a system has been considered in which the numerical aperture (NA) is increased and the substrate thickness t of the optical disk is reduced without narrowing the allowable range of the tilt of the optical disk with respect to the objective lens.
For example, a compact disk uses a substrate having a thickness of 1.2 mm, while a DVD uses a substrate having a thickness of 0.6 mm.

In an optical pickup device using an objective lens optimized for an optical disk using a thin substrate, when reproducing an existing optical disk, for example, a compact disk or a write-once optical disk,
Due to the difference in the thickness of the disc, there is a problem that a high-quality reproduced signal cannot be obtained for the reason described later.

Generally, the amount of fourth-order spherical aberration normalized by the wavelength of light generated by a parallel plate in a convergent light beam is proportional to the fourth power of the numerical aperture NA of the objective lens. The transmitted wavefront W (x, y) of this light on the flat plate is expressed by the following equation (1). W (x, y) = W ₁ (x ² + y ² ) ² (1) Here, W 1 is a fourth-order spherical aberration, and is expressed by the following equation (2) when expressed by a so-called Seidel aberration coefficient equation. expressed. W ₁ = (n ² −1) tNA ⁴ / 8n ³ λ (2) In equation (2), n is the refractive index of the optical disk, t is the substrate thickness of the optical disk, NA is the numerical aperture of the objective lens, λ represents a wavelength.

Therefore, the thickness t of the substrate of the optical disk is 0.6.
When an optical disk having a substrate thickness t of 1.2 mm is reproduced by using an objective lens having a numerical aperture of 0.6 optimized in mm, the amount of generated spherical aberration is about the fourth-order Seidel spherical aberration coefficient. It becomes 3.6 μm. If such a large aberration occurs on the optical disk substrate, the optical disk system cannot be established. Therefore, in the optical pickup device shown in FIG. 4, it is difficult to read information from a plurality of types of optical disks having different thicknesses of the disk substrate.

The present invention has been proposed in view of the above-mentioned problems, and has an optical disk system capable of reliably maintaining compatibility of optical disks having different substrate thicknesses without deteriorating recording and reproduction signals. It is intended to provide.

[0009]

According to a first aspect of the present invention, there is provided an optical pickup device for irradiating a plurality of types of optical disks having different substrate thicknesses with a light beam to record and / or reproduce information. In the pickup device,
A semi-reflective film that transmits a part of the incident light and reflects a part thereof, and a light beam transmitted through the semi-reflective film, the light beam reflected by the semi-reflective film by giving an aberration to the light beam, A total reflection film for converting a light beam capable of forming a minute spot on an optical disk having a different substrate thickness.

According to a second aspect of the present invention, there is provided an optical pickup device for recording and / or reproducing information by irradiating a plurality of types of optical disks having different substrate thicknesses with a light beam. Emitting light source,
A polarizing beam splitter that reflects or transmits linearly polarized light from the light-emitting source, a quarter-wave plate arranged to receive a light beam reflected or transmitted by the polarizing beam splitter, and a quarter-wave plate. A semi-reflective film that transmits a part of the transmitted light beam and reflects a part of the light beam to the quarter-wave plate, and is different from the light beam reflected by the semi-reflective film to the light beam transmitted through the semi-reflective film. A total reflection film that gives an aberration and reflects to the quarter-wave plate, a light beam reflected by the semi-reflection film, and the total reflection film so that a minute spot can be formed on an optical disk having a substrate thickness. And an objective lens for condensing the light beam reflected by the above through the 波長 wavelength plate and the polarizing beam splitter.

The optical pickup device according to claim 3 is
In the optical pickup device according to claim 1 or 2, the semi-reflective film is formed so as to have partially different reflectance and transmittance.

The optical pickup device according to claim 4 is
3. The optical pickup device according to claim 1, wherein the semi-reflective film has a light transmission hole in a central portion, and the total reflection film guides a light beam reflected into the light transmission hole. 4. It is formed as follows.

An optical pickup device according to a fifth aspect of the present invention comprises:
The optical pickup device according to any one of claims 1 to 4, further comprising a regulating member that regulates a light beam other than a central portion of the light beam transmitted through the semi-reflective film so as not to be guided to the optical disc.

According to a sixth aspect of the present invention, there is provided an optical pickup device comprising:
An optical pickup device that irradiates a plurality of types of optical disks having different substrate thicknesses with a light beam to record and / or reproduce information;
A polarizing beam splitter that reflects or transmits linearly polarized light from the light-emitting source, a quarter-wave plate arranged to receive a light beam reflected or transmitted by the polarizing beam splitter, and a quarter-wave plate. Diffracts the transmitted light beam to obtain the 1
A reflection type hologram element for reflecting to a 波長 wavelength plate, and an objective lens for condensing a light beam reflected by the hologram element through the 波長 wavelength plate and the polarizing beam splitter, The diffraction grating is set so that the hologram element forms a minute spot on the optical disc having a plurality of different substrate thicknesses with the light beam condensed by the objective lens.

An optical pickup device according to claim 7 is
7. The optical pickup device according to claim 6, wherein the hologram element includes a hologram region in a central portion and a total reflection region in another portion.

An optical pickup device according to claim 8 is
The optical pickup device according to claim 2 or 6, wherein the objective lens and the polarization beam splitter are formed to be driven by the same actuator.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic diagram showing a configuration of an optical pickup device according to the present embodiment.
This optical pickup device is configured to be compatible with two types of optical information recording media 48 and 52 having different thicknesses, and includes a laser diode 41 as a light source, a polarizing beam splitter 42, and a 波長 wavelength plate 44. , A semi-reflective film 51 that transmits 90% of the incident light beam and reflects 10%, a reflective lens 45, a quarter-wave plate 46, an objective lens 47, a multi-lens 49, and a photodiode 5 as a photodetector.
It consists of zero.

The light splitting surface 43 of the polarization beam splitter 42 has a characteristic of reflecting S-polarized light and transmitting P-polarized light. The semi-reflective film 51 is formed to transmit 90% of the incident light and reflect the remaining 10%. Further, the objective lens 47 is designed so as to be compatible with the optical information recording medium 52, that is, optimally designed so that the spherical aberration amount becomes almost zero for the optical information recording medium. . The reflective lens 45 is formed by evaporating a total reflection film that totally reflects the incident light beam on the concave surface of the plano-concave lens,
The inside is used as a convex mirror. Further, the concave shape of the reflective lens 45 gives a spherical aberration to the light beam incident on the objective lens 47 (which is suitable for the optical information recording medium 52 as described above), and a minute spot on the optical information recording medium 48. Optimally designed to connect

The operation of the optical pickup device will be described below. Assuming that the light beam from the laser diode 41 is S-polarized light whose vibration direction is perpendicular to the plane of the paper, the divergent emitted light beam is incident on the polarizing beam splitter 42,
The light is reflected by the light dividing surface 43 formed in the direction of 5 degrees. After passing through the quarter-wave plate 44, the light enters the semi-reflective film 51. In the present embodiment, the operation greatly differs depending on whether the light is transmitted or reflected through the semi-reflective film 51.
Hereinafter, (1) an optical path of a light beam transmitted through the semi-reflective film 51 and (2) an optical path of a light beam reflected by the semi-reflective film 51 will be separately described in detail.

(1) First, the light beam transmitted through the semi-reflective film 51 is reflected by a reflective lens (plano-concave lens) 45 having a total reflection film for totally reflecting the incident light beam. Here, the concave shape of the plano-concave lens 45 gives the incident light an aberration for correcting the difference in the disk thickness, as described above. The light beam reflected by the reflective lens 45 passes through the semi-reflective film 51 and the quarter-wave plate 44 again. At this point, the light beam has passed through the quarter-wave plate 44 twice, so that the vibration direction is P-polarized light parallel to the paper surface. This P-polarized light beam passes through the above-described light splitting surface 43, becomes a circularly polarized light by the 板 wavelength plate 46, forms a minute spot on the optical information recording medium 48 via the objective lens 47, and Performs recording, playback, and erasure.

The reflected light from the optical information recording medium 48 passes through the quarter-wave plate 46 via the objective lens 47, and then becomes S-polarized light whose vibration direction is perpendicular to the plane of the drawing. 43, the light is reflected at a right angle, passes through a multi-lens 49, and is a photodiode 5 as a photodetector.
Enter 0. In the photodiode 50, the information of the incident light is converted into an electric signal to be a focus error signal and a tracking error signal, which are used as a reference for a servo operation by various servo mechanisms of the optical disk player.

(2) Next, the light beam reflected by the semi-reflective film 51 passes through the quarter-wave plate 44, becomes P-polarized light, and then passes through the light splitting surface 43 of the polarizing beam splitter as diffused light. To do. Then, the light becomes circularly polarized light by the 板 wavelength plate 46,
A minute spot is formed on the optical information recording medium 52 via the objective lens 47 to reproduce information.

The reflected light from the optical information recording medium 52 is
After passing through the quarter-wave plate 46 via the objective lens 47, the vibration direction becomes S-polarized light perpendicular to the paper surface, reflected at a right angle by the light splitting surface 43 of the polarizing beam splitter, and passed through the multi-lens 49. Photodiode 50 as a detector
to go into. The information of the incident light in the photodiode 50 is converted into an electric signal to be a focus error signal and a tracking error signal, which are used as a reference for servo operations by various servo mechanisms of the optical disk player.

As described above, in the optical pickup device of the present embodiment, the light beam from the laser diode 41 forms a spot on the optical information recording medium 48 and the optical information recording medium 52 at the same time. Therefore, the compatibility of the optical disks having different thicknesses can be reliably maintained without deteriorating the recording and reproduction signals. Further, with the above configuration, it is possible to reduce the size and weight of the optical pickup device that can support a plurality of optical information recording media.

In the present embodiment, about 80% of the power of the light emitted from the laser diode is λ / 4 plate 46.
Through an objective lens 47 and an optical information recording medium 48
About 10% of the light passes through the λ / 4 plate 46 and is condensed on the optical information recording medium 52 via the objective lens 47. Here, the transmittance and the reflectance of the semi-reflective film are 90% and 10%, respectively.
However, since the required power varies depending on the type and application of each medium, the values of the transmittance and the reflectance of the semi-reflective film are not limited to these values.

Further, in this embodiment, as the semi-reflective film, a semi-reflective film is used. However, as shown in FIG. 2, a semi-reflective film 151 having a curved surface may be used. In the optical pickup device of FIG. 2, the objective lens 47 is optimally designed with respect to the optical information recording medium 48 so that the amount of spherical aberration generated in the device is almost zero. The curvature of the semi-reflective film 151 is optimally designed for aberration compensation so as to connect minute spots on the optical information recording medium 52 via the lens 47. Therefore, according to this configuration, it is possible to form a spot on the optical information recording medium 48 and the optical information recording medium 52 at the same time. At this time, the semi-reflective film 151 and the reflective lens 45 are integrated,
As shown in FIG. 3, a concave lens 101 may be provided with a total reflection film 102 for totally reflecting an incident light beam on one concave surface and a semi-reflective film 100 on the other concave surface.

As a modification of the optical pickup shown in FIG. 1, a quarter-wave plate 4
4, semi-reflective film 51, reflective lens 45, quarter-wave plate 4
FIG. 4 shows an example in which 6 is joined or formed. With such a configuration, the space of the optical system of the optical pickup device can be reduced, which is advantageous for miniaturization of the device. In addition, the number of parts is reduced, which is advantageous in cost. In the optical pickup device shown in FIG. 4, the objective lens 47 and the polarization beam splitter 42
However, by using a cylindrical holder or the like and integrally driving with the same actuator, the displacement between the lens center and the optical axis center due to the movement of the objective lens is eliminated, and the compatibility of the optical disk is improved. Recording and reproduction signals can be maintained more reliably without deterioration.

(Embodiment 2) FIG. 5 is a schematic diagram showing a configuration of an optical pickup device of the present embodiment. Less than,
The optical pickup device according to the present embodiment will be described with reference to FIG.

In this optical pickup device, a laser diode 21 as a light source, polarization beam splitters 22,
波長 wavelength plate 24 transmits 90% of incident light flux and transmits 10%
, A reflective lens 25, a quarter-wave plate 26, an objective lens 27, a multi-lens 29, and a photodiode 30 as a photodetector.

The light splitting surface 23 of the polarizing beam splitter 22 has a characteristic of reflecting S-polarized light and transmitting P-polarized light. The semi-reflective film 1 has 9
It is formed so as to transmit 0% and reflect the remaining 10%. The objective lens 27 is designed to be compatible with the optical information recording medium 18, that is, optimally designed so that the spherical aberration amount of the optical information recording medium 18 is almost zero. I have. The reflective lens 25 is formed by depositing a total reflection film for totally reflecting the incident light beam on the concave surface of the plano-concave lens, and uses the inside thereof as a convex mirror. Further, the concave shape of the reflective lens 25 gives a spherical aberration to the light beam incident on the objective lens 27 (which is suitable for the optical information recording medium 18 as described above), and a minute spot on the optical information recording medium 28. Optimally designed to connect

The operation of the optical pickup device according to this embodiment will be described below. The luminous flux from the laser diode 21 is converted into P-polarized light whose oscillation direction is parallel to the plane of the drawing. The divergent emitted luminous flux enters the polarization beam splitter 22, passes through the light splitting surface 23, and passes through the 波長 wavelength plate 24. After that, the light enters the semi-reflective film 1. 90% of the light beam incident on the semi-reflective film 1 is transmitted, and the remaining 10% is reflected. Here, in the present embodiment, the light flux passing through the semi-reflective film 1 is
The optical path is different from the light beam reflected by the semi-reflective film 1. Hereinafter, (3) the optical path of the light flux transmitted through the semi-reflective film 1,
(4) The optical path of the light beam reflected by the semi-reflective film 1 will be described in detail by dividing into two light paths.

(3) First, the light beam transmitted through the semi-reflective film 1 is reflected by a plano-concave lens 25 having a total reflection film for totally reflecting the incident light beam. Here, as described above, the concave shape of the plano-concave lens 25 adds an aberration to a light beam incident on the objective lens 27 (which is suitable for the optical information recording medium 18), and causes a minute spot on the optical information recording medium 28. Optimally designed to connect The light beam reflected by the plano-concave lens 25 passes through the 波長 wavelength plate 24. At this point, the light beam passes through the quarter-wave plate 24 twice,
The vibration direction becomes S-polarized light perpendicular to the paper surface. Further, the S-polarized parallel light is reflected at a right angle by the light splitting surface 23, becomes a circularly polarized light by the quarter wavelength plate 26, and
A minute spot is formed on the optical information recording medium 28 through the recording medium 7 to record, reproduce, and erase information.

The reflected light from the optical information recording medium 28 passes through the quarter-wave plate 26 via the objective lens 27, and then becomes P-polarized light whose vibration direction is parallel to the plane of the drawing. Photodiode 3, which is reflected at a right angle by split surface 2 and passes through multi-lens 29, is a photodetector.
Enter 0. The information of the incident light in the photodiode 30 is converted into an electric signal to be a focus error signal and a tracking error signal, which are used as a reference for a servo operation by various servo mechanisms of the optical disk player.

(4) Next, the light beam reflected by the semi-reflective film 1 passes through the quarter-wave plate 24, becomes S-polarized light, and passes through the light splitting surface 23 of the polarizing beam splitter. Then, the light is converted into circularly polarized light by the １ ／ wavelength plate 26, and the objective lens 27
Then, a minute spot is formed on the optical information recording medium 18 via the optical disc and the information is reproduced.

The reflected light from the optical information recording medium 18 is
After passing through the quarter-wave plate 26 via the objective lens 27, the light becomes P-polarized light whose vibration direction is parallel to the paper surface. Then, the light is reflected at a right angle by the light splitting surface 23 of the polarizing beam splitter, passes through the multi-lens 29, and enters the photodiode 30 as a photodetector. The information of the incident light in the photodiode 30 is converted into an electric signal to be a focus error signal and a tracking error signal, which are used as a reference for a servo operation by various servo mechanisms of the optical disk player.

As described above, the optical pickup device according to the present embodiment can form spots on the optical information recording medium 28 and the optical information recording medium 18 at the same time. Can be reliably maintained without deterioration.

In this embodiment, about 80% of the power of the light emitted from the laser diode is λ / 4 plate 26.
Through the objective lens 27 and the optical information recording medium 28
Is irradiated. On the other hand, about 10% of the light passes through the λ / 4 plate 26 and irradiates the optical information recording medium 18 via the objective lens 27. Here, the transmissivity and the reflectivity of the semi-reflective film are set to 90% and 10%, respectively. However, since the required power varies depending on the type and use of each medium, the transmissivity and the reflectivity of the semi-reflective film are different. The values are not limited to these values.

FIG. 6 is a schematic diagram showing a modification of the present embodiment. In this embodiment, a quarter-wave plate 24, a semi-reflective film 1, a reflective lens 25,
The 波長 wavelength plate 26 is joined or formed. With such a configuration, the space for the optical system is reduced, which is advantageous for miniaturization of the device. In addition, the number of parts is reduced, which is advantageous in cost.

In the optical pickup device shown in FIG. 6, the objective lens and the polarizing beam splitter are separated from each other. However, the objective lens is integrally driven by the same actuator using a cylindrical holder or the like. The displacement between the center of the lens and the center of the optical axis due to the movement of the optical disk is eliminated, and the compatibility of the optical disk can be more reliably maintained without deteriorating the recording and reproduction signals.

(Embodiment 3) FIG. 7 is a schematic diagram showing a configuration of an optical pickup device according to the present embodiment.
Here, a laser diode 81 as a light source, a collimator lens 93, a polarizing beam splitter 82,.
Wave plate 84, semi-reflective film 91 that transmits 10% of the incident light beam and reflects 90%, a reflective lens 85, quarter wave plate 86, objective lens 87, multi-lens 89, and a photo that is a photodetector. A diode 90.

The light splitting surface 83 of the polarization beam splitter 82 has a characteristic of reflecting S-polarized light and transmitting P-polarized light. The semi-reflective film 91 is formed to transmit 20% of the incident light and reflect the remaining 80%. The objective lens 87 is designed to be compatible with the optical information recording medium 88, that is, optimally designed so that the spherical aberration amount of the optical information recording medium 88 is almost zero. I have. The reflection type lens 85 is formed by depositing a total reflection film for totally reflecting an incident light beam on the concave surface of the plano-concave lens, and uses the inside thereof as a convex mirror. Further, the concave shape of the reflective lens 85 gives a spherical aberration to the light beam incident on the objective lens 87 (adapted to the optical information recording medium 88 as described above), and causes a minute spot on the optical information recording medium 92. Optimally designed to connect

Hereinafter, the operation of the optical pickup device of the present invention will be described. Assuming that the luminous flux from the laser diode 81 is S-polarized light whose vibration direction is perpendicular to the plane of the paper, the divergent emitted luminous flux passes through the collimator lens 93, is converted into parallel light, and then enters the polarization beam splitter 82, The light is reflected by the light splitting surface 83 formed in the direction of 45 degrees with respect to the axis, passes through the 波長 wavelength plate 84, and then enters the semi-reflective film 91. Thereafter, the light beam transmitted through the semi-reflective film 91 and the light beam reflected by the semi-reflective film 91 pass through different optical paths. Hereinafter, (5) an optical path of a light beam reflected by the semi-reflective film 91 and (6) an optical path of a light beam transmitted through the semi-reflective film 91 will be described in detail.

(5) First, the light beam reflected by the semi-reflective film 91 passes through the quarter-wave plate 84 and becomes P-polarized light.
The light passes through the light splitting surface 83 of the polarizing beam splitter. Then, the light becomes circularly polarized by the １ ／ wavelength plate 86,
A minute spot is formed on the optical information recording medium 88 via the, and information is recorded, reproduced, and erased. The reflected light from the optical information recording medium 88 passes through the objective lens 87 and
After passing through the wave plate 86, the vibration direction becomes S-polarized light perpendicular to the paper surface, is reflected at a right angle by the light splitting surface 83 of the polarizing beam splitter, passes through the multi-lens 89, and enters the photodiode 90 as a photodetector. . The information of the incident light is converted into an electric signal in the photodiode 90,
These signals are a focus error signal and a tracking error signal, and are used as references for servo operations by various servo mechanisms of the optical disk player.

(6) Next, the light beam transmitted through the semi-reflective film 91 is reflected by the plano-concave lens 85 having a total reflection film for totally reflecting the incident light beam. The concave shape of the plano-concave lens 85 is designed to connect a minute spot to the optical information recording medium 92 via the objective lens 87 as described above. The light beam transmitted through the plano-concave lens 85 passes through the semi-reflective film 91 and the quarter-wave plate 84 again. At this time, since the incident light passes through the quarter-wave plate 84 twice, it becomes P-polarized light whose vibration direction is parallel to the paper surface. Further, this P-polarized light beam passes through the above-described light splitting surface 83, becomes a circularly polarized light by the quarter-wave plate 86, and becomes an objective lens 87.
A minute spot is formed on the optical information recording medium 92 through the optical disk, and information is reproduced.

Here, since the light beam incident on the objective lens 87 is diffused light, the optical information recording medium 92 has a larger disk thickness than the optical information recording medium 88 on which recording, reproduction, and erasure have been performed in (5). It is possible to form a spot on the board surface. This reflected light passes through the quarter-wave plate 86 via the objective lens 87, becomes S-polarized light whose vibration direction is perpendicular to the paper surface, is reflected at a right angle by the light splitting surface 83 of the polarizing beam splitter, and becomes a multi-lens 89. And enters a photodiode 90 as a photodetector. This photodiode 9
At 0, the information of the incident light is converted into an electric signal to be a focus error signal and a tracking error signal, and is used as a reference for a servo operation by various servo mechanisms of the optical disc player device.

As described above, the optical pickup device according to the present embodiment having such a configuration can be used for the optical information recording medium 8.
8 and the optical information recording medium 92 can be simultaneously formed on the optical information recording medium 92, and the compatibility of the optical disk can be reliably maintained without deteriorating the recording and reproduction signals. In the present embodiment, about 80% of the power of the light emitted from the laser diode passes through the λ / 4 plate 86, is irradiated on the optical information recording medium 88 via the objective lens 87, and is about 4%. Passes through the λ / 4 plate 86, passes through the objective lens 87,
The optical information recording medium 92 is irradiated. Here, the transmissivity and the reflectivity of the semi-reflective film are set to 20% and 80%, respectively. However, the required power varies depending on the type and use of each medium. The values are not limited to these values.

Further, a light-shielding film 555 (a regulating member in claims) as shown in FIG. 8A is provided between the semi-reflective film 91 and the reflective lens 85, or as shown in FIG. By optimally designing the concave shape of the reflective lens 85 and providing a regulating reflection area (a regulating member in the claims) on the outer peripheral portion, the numerical aperture of the light beam reflected by the reflective lens 85 to the objective lens 87 is further increased. It can be smaller. In the present embodiment, the laser diode 8
A collimator lens 93 is provided between the first and second polarizing beam splitters 82 to make parallel light before entering the polarizing beam splitter 82. Further, a shaping prism is arranged between the collimator lens 93 and the polarizing beam splitter 82 to form a beam. , A good spot can be obtained on the optical information recording medium. At this time, the shaping prism may be joined to the polarizing beam splitter.

(Embodiment 4) FIG. 9 is a schematic diagram showing a configuration of an optical pickup device of the present embodiment. As shown in this figure, the present optical pickup device transmits a laser diode 381 as a light source, a collimator lens 393, a polarizing beam splitter 382, a quarter-wave plate 384, and transmits 20% of incident light flux and reflects 80%. Semi-reflective film 3
It comprises a reflective lens 91, a reflective lens 385, a 波長 wavelength plate 386, an objective lens 387, a multi-lens 389, and a photodiode 390 as a photodetector.

The light splitting surface 383 of the polarizing beam splitter 382 has a characteristic of reflecting S-polarized light and transmitting P-polarized light. The semi-reflective film 391 is formed so as to transmit 20% of the incident light and reflect the remaining 80%. The objective lens 387 is designed to be compatible with the optical information recording medium 388.
That is, the optical information recording medium 388 is optimally designed so that the spherical aberration amount is almost zero. The reflection type lens 385 is formed by depositing a total reflection film for totally reflecting an incident light beam on the convex surface of the plano-convex lens, and using the inside thereof as a concave mirror. Furthermore, the convex shape of the reflective lens 385 is
It is optimally designed to give a spherical aberration to a light beam incident on the optical information recording medium 392 (suitable for the optical information recording medium 388 as described above) and to form a minute spot on the optical information recording medium 392.

Hereinafter, the operation of the optical pickup device according to this embodiment will be described. Assuming that the light beam from the laser diode 381 is S-polarized light whose vibration direction is perpendicular to the plane of the drawing, the divergent emitted light beam becomes parallel light after passing through the collimator lens 393, and enters the polarization beam splitter 382.
Then, a light dividing surface 38 formed in a direction of 45 degrees with respect to the optical axis.
After being reflected by 3 and passing through the quarter-wave plate 384, it enters the semi-reflective film 391. As described above, the semi-reflective film 39
20% of the light beam incident on 1 is transmitted, and the remaining 80% is reflected. Thereafter, the light transmitted through the semi-reflective film 391 and the reflected light follow different optical paths. Hereinafter, (7) the optical path of the light beam reflected by the semi-reflective film 391, (8) the semi-reflective film 391
The optical path of the light flux transmitted through the optical path will be described in detail.

(7) First, the light beam reflected by the semi-reflective film 391 passes through the quarter-wave plate 384 and becomes P-polarized light.
Then, the light passes through the light splitting surface 383 of the polarizing beam splitter, becomes a circularly polarized light by the 波長 wavelength plate 386, and
A minute spot is formed on the optical information recording medium 388 via the recording medium 87 to record, reproduce, and erase information.

The reflected light from the optical information recording medium 388 passes through the quarter-wave plate 386 via the objective lens 387, and then becomes S-polarized light whose vibration direction is perpendicular to the paper plane. At 383, it is reflected at right angles. Then, the light passes through the multi-lens 389 and enters the photodiode 390 which is a photodetector. The information of the incident light in the photodiode 390 is converted into an electric signal to be a focus error signal and a tracking error signal, and is used as a reference for a servo operation by various servo mechanisms of the optical disk player.

(8) Next, the light beam transmitted through the semi-reflective film 391 is reflected by a plano-convex lens 385 having a total reflection film for totally reflecting the incident light beam, and is again reflected by the semi-reflective film 391 and the 波長 wavelength. Passes through plate 384. At this point, the incident light passes through the quarter-wave plate 384 twice,
The vibration direction is P-polarized light parallel to the paper. Further, this P-polarized light beam passes through the above-described light dividing surface 383, once forms an image point 399, becomes a circularly polarized light by a quarter wavelength plate 386, and passes through an objective lens 387 to an optical information recording medium. A minute spot is formed at 392 to reproduce information.
Here, the light beam incident on the objective lens is reflected by the reflection type lens 3.
Since the aberration is compensated by 85, it is possible to form a spot on the surface of the optical information recording medium 392 having a larger disk thickness than the optical information recording medium 388 on which recording, reproduction, and erasure were performed in (7). It is possible.

The reflected light from the optical information recording medium 392 passes through the quarter wavelength plate 386 via the objective lens 387,
The vibration direction is S-polarized light perpendicular to the paper surface, reflected at a right angle by the light splitting surface 383 of the polarization beam splitter, and passed through the multi-lens 389 to enter the photodiode 390 as a photodetector. The information of the incident light in the photodiode 390 is converted into an electric signal to be a focus error signal and a tracking error signal, and is used as a reference for a servo operation by various servo mechanisms of the optical disk player.

As described above, the optical pickup device of the present embodiment comprises the optical information recording medium 388 and the optical information recording medium 39.
2 can be formed at the same time, and the compatibility of the optical disc can be reliably maintained without deteriorating the recording and reproduction signals.

In this embodiment, about 80% of the power of the light emitted from the laser diode 381 is λ / 4 plate 3
The laser beam passes through the objective lens 387 and irradiates the optical information recording medium 388 through the objective lens 387. About 4% of the light passes through the λ / 4 plate 386 and irradiates the optical information recording medium 392 through the objective lens 387.

Here, the transmissivity and the reflectivity of the semi-reflective film 391 are set to 20% and 80%, respectively. However, since the required power differs depending on the type and use of each medium, the transmissivity of the semi-reflective film is determined. , And the reflectance values are not limited to these values.

In the present embodiment, the reflection type lens 3
An image point 399 by 85 is located between the light splitting surface 383 of the polarizing beam splitter 382 and the λ / 4 plate 386,
What is necessary is just to be between the reflective lens 385 and the objective lens 387.

In the present embodiment, the collimator lens 393 is provided between the laser diode 381 and the polarization beam splitter 382, and the collimator lens 393 is formed into parallel light before entering the polarization beam splitter 382. By arranging a shaping prism between the beam splitters 382 and expanding the beam, a good spot can be obtained on the optical information recording medium. At this time, the shaping prism may be joined to the polarizing beam splitter.

(Embodiment 5) An optical pickup device according to the present embodiment is the same as the optical pickup device described above, except that a semi-reflective film having partially different reflectance and transmittance is used. FIG. 10 is a schematic diagram illustrating a configuration of the optical pickup device according to the present embodiment. As shown in this figure, a laser diode 881 as a light source, a collimator lens 893, a polarization beam splitter 882,
Quarter-wave plate 884, semi-reflective film 891, reflective lens 8
85, 1/4 wavelength plate 886, objective lens 887, multi-lens 889, and photodiode 8 as a photodetector
90.

The light splitting surface 883 of the polarizing beam splitter 882 has a characteristic of reflecting S-polarized light and transmitting P-polarized light. The semi-reflective film 891 has a transmittance of 90% and a reflectance of 10% at the center and a transmittance of 10% at the periphery.
% And a reflectance of 90%. The objective lens 887 is set so as to be compatible with the optical information recording medium 888. That is, the objective lens 887 is optimally designed so that the amount of spherical aberration becomes almost zero when a light beam enters the optical information recording medium 888. I have. The reflection type lens 885 is formed by depositing a total reflection film for totally reflecting the incident light beam on the concave surface of the plano-concave lens, and using the inside as a convex mirror. Also, this concave shape is
An aberration is given to the light beam incident on the objective lens 887 so that the light beam from the objective lens 887 is
2 is set to form a minute spot.

The operation of the optical pickup device according to this embodiment will be described below. Assuming that the light beam from the laser diode 881 is S-polarized light whose vibration direction is perpendicular to the plane of the paper, the divergent emitted light beam passes through the collimator lens 893, is converted into parallel light, and then enters the polarization beam splitter 882. After that, the light is reflected by the light dividing surface 883 formed in the direction of 45 degrees with respect to the optical axis, passes through the 波長 wavelength plate 884,
The light enters the semi-reflective film 891. Thereafter, the light beam transmitted through the semi-reflective film 891 and the light beam reflected follow different optical paths. Hereinafter, (9) the optical path of the light beam reflected by the semi-reflective film 891,
(10) The optical path of the light beam transmitted through the semi-reflective film 891 will be described in detail.

(9) Of the light beam incident on the semi-reflective film 891, 10% is reflected at the central portion and 90% is reflected at the peripheral portion. The luminous flux reflected by the semi-reflective film 891 becomes 1 again.
After passing through a 波長 wavelength plate 884 and being converted into a P-polarized light beam,
After passing through the light splitting surface 883 of the polarizing beam splitter,
The light passes through the four-wavelength plate 886 and is converted into circularly polarized light.
It is incident on 87. As a result, the laser diode 881
Approximately 10% of the luminous flux emitted from the central part and about 90% at the peripheral part enter the objective lens. The light flux condenses a minute spot on the optical information recording medium 888.

(10) Of the light beam incident on the semi-reflective film 891, 90% is transmitted at the central portion and 10% is transmitted at the peripheral portion. The light beam transmitted through this semi-reflective film is reflected
85, the semi-reflective film 891, the quarter-wave plate 8 again
The light passes through 84 and is converted into a P-polarized light beam. Then, the light passes through the light splitting surface 883 of the polarizing beam splitter, passes through the quarter-wave plate 886, and is converted into circularly polarized light.
Incident on. As a result, of the light beam emitted from the laser diode, about 80% at the center and about 1% at the periphery enter the objective lens, and after being reflected by the above-mentioned semi-reflective film, it went toward the objective lens. Compared with the light beam, the intensity ratio of the central portion to the beam peripheral portion is very large. The light flux at the central portion of the high intensity is shown by hatching in FIG. The NA of the objective lens 887 with respect to the light beam in the hatched portion becomes smaller than the NA with respect to the light beam that is reflected by the semi-reflective film and then travels toward the objective lens.
Light can be focused on the information recording medium 892 thicker than the information recording medium 888.

As described above, the optical pickup device of the present embodiment comprises the optical information recording medium 888 and the optical information recording medium 8.
It is possible to simultaneously form spots on
The compatibility of the optical disk can be reliably maintained without deteriorating the recording and reproduction signals.

The light beams reflected by the information recording medium 888 and the information recording medium 892 are reflected by the objective lens 887 and the λ.
The light passing through the / 4 plate 886 is reflected at a right angle by the light splitting surface 883 of the polarizing beam splitter, passes through the multi-lens 889, and enters the photodiode 890 as a photodetector. The information of the incident light in the photodiode 890 is converted into an electric signal to be a focus error signal and a tracking error signal, which are used as a reference for a servo operation by various servo mechanisms of the optical disk player.

The polarization beam splitter 882 applies λ /
FIG. 11 shows an example in which four plates 884, a semi-reflective film 891, a reflective lens 885, and a λ / 4 plate 886 are joined or formed. In the pickup device of FIG. 11, the space for the optical system is reduced, which is advantageous for miniaturization of the device. In addition, the number of parts is reduced, which is advantageous in cost.

Although the objective lens and the polarizing beam splitter are separated here, they are integrally driven by the same actuator using a cylindrical holder or the like, so that the center of the lens accompanying the movement of the objective lens is reduced. And the center of the optical axis is eliminated, and the compatibility of the optical disk can be more reliably maintained without deteriorating the recording and reproduction signals.

(Embodiment 6) As shown in FIG. 12, the optical pickup device of this embodiment includes a laser diode 981 as a light source, a collimator lens 993, a polarizing beam splitter 982, a quarter-wave plate 984, Semi-reflective film 99 that transmits 10% of incident light and reflects 90%
1, reflection mirror 998, reflection lens 985, quarter wave plate 986, objective lens 987, multi lens 989,
And a photodiode 990 as a photodetector.

The light splitting surface 983 of the polarizing beam splitter has a characteristic of reflecting S-polarized light and transmitting P-polarized light. The semi-reflective film 991 is provided with a minute hole (a transmission hole in the claims) at the center thereof. Also, 10% of the luminous flux incident on the semi-reflective film 991
Is transmitted and the remaining 90% is reflected. Further, the objective lens 987 is an optical information recording medium 988.
In other words, it is optimally designed so that the amount of spherical aberration becomes substantially zero when a light beam enters the optical information recording medium 988. Reflective lens 9
Reference numeral 85 denotes a vapor deposition of a total reflection film for totally reflecting the incident light beam on the convex surface of the plano-convex lens, and the inside thereof is used as a concave mirror. The convex shape is set so as to give an aberration to the light beam incident on the objective lens 987 so that the light beam from the objective lens 987 forms a minute spot on the optical information recording medium 992.

The operation of the optical pickup device according to the present embodiment will be described below. Assuming that the light beam from the laser diode 981 is S-polarized light whose vibration direction is perpendicular to the plane of the paper, the divergent emitted light beam becomes parallel light after passing through the collimator lens 993, enters the polarization beam splitter 982, and then enters the optical axis 45 °. After being reflected by the light splitting surface 983 formed in the direction of 度 and passing through the 波長 wavelength plate 984, the semi-reflective film 9
It is incident on 91. Thereafter, the optical path of the light beam transmitted through the semi-reflective film 991 is different from the optical path of the reflected light beam. less than,
(11) The optical path of the light beam transmitted through the semi-reflective film 991, (1
2) The optical path of the light beam reflected by the semi-reflective film 991 will be described separately.

(10) First, the light beam reflected by the semi-reflective film 991 passes through the quarter-wave plate 984 and becomes P-polarized light. Then, the light passes through the light splitting surface 983 of the polarizing beam splitter, becomes a circularly polarized light by the 波長 wavelength plate 986, forms a minute spot on the optical information recording medium 988 via the objective lens 987, and records, reproduces, and records information. Perform erasure.

The reflected light from the optical information recording medium 988 passes through the quarter-wave plate 986 via the objective lens 987, and then becomes S-polarized light whose vibration direction is perpendicular to the paper plane. Reflected at right angles at 983,
The light passes through a multi-lens 989 and enters a photodiode 990 as a photodetector. The information of the incident light in the photodiode 990 is converted into an electric signal, and is converted into a focus error signal and a tracking error signal, which are used as a reference for a servo operation by various servo mechanisms of the optical disk player.

(10) Next, the light beam transmitted through the semi-reflective film 991 is reflected by the reflection mirror 998 and then reflected by the plano-convex lens 985 having the total reflection film for totally reflecting the incident light beam. Then, the light is reflected again by the reflection mirror 998, connects the image point 999 at the position of the hole of the semi-reflection film 991, becomes diffused light, and passes through the quarter-wave plate 984 again. At this point, the incident light passes through the quarter-wave plate 984 twice, and becomes a P-polarized light whose vibration direction is parallel to the paper surface. Further, this P-polarized light beam is reflected by the light splitting surface 98 described above.
3, the light is converted into circularly polarized light by the quarter-wave plate 986, and a minute spot is formed on the optical information recording medium 992 via the objective lens 987 to reproduce information. Here, since the aberration of the light beam incident on the objective lens is compensated by the reflective lens 985, the light beam having a larger disc thickness than the optical information recording medium 988 recorded, reproduced, and erased in (9). A spot can be formed on the surface of the information recording medium 992.

The reflected light from the optical information recording medium 992 passes through the quarter wavelength plate 986 via the objective lens 987,
The oscillation direction becomes S-polarized light perpendicular to the paper surface, and is reflected at a right angle by the light splitting surface 983 of the polarization beam splitter, passes through the multi-lens 989, and enters the photodiode 990 as a photodetector. The information of the incident light in the photodiode 990 is converted into an electric signal to be a focus error signal and a tracking error signal, and is used as a reference for a servo operation by various servo mechanisms of the optical disk player.

As described above, the optical pickup device of the present embodiment comprises the optical information recording medium 988 and the optical information recording medium 9.
It is possible to simultaneously form spots on
The compatibility of the optical disk can be reliably maintained without deteriorating the recording and reproduction signals.

Further, after the light beam transmitted through the semi-reflective film 991 is reflected by the totally reflective film, it does not pass through the semi-reflective film again, and the λ / 4 plate 984, the light splitting surfaces 983 and λ / 4 Since the light passes through the plate 986 and enters the objective lens, the utilization efficiency of the light beam is extremely high.

Further, the optical pickup device of the present invention having such a configuration can use a laser diode having a relatively low power because of high light beam utilization efficiency, and is advantageous in cost. In this embodiment, about 90% of the power of the light emitted from the laser diode is about 90%.
The light passes through 86, irradiates the optical information recording medium 988 through the objective lens 987, and about 10% passes through the λ / 4 plate 986, and irradiates the optical information recording medium 992 through the objective lens 987.

In this case, the transmittance and the reflectance of the semi-reflective film are set to 10% and 90%, respectively. However, the required power varies depending on the type and use of each medium. The values of the reflectance and the reflectance are not limited to these values. Further, in the present embodiment, a hole is formed at the center of the semi-reflective film. However, it is also within the scope of the present invention that a full-transmission area is provided at the center of the semi-reflective film. Needless to say.

(Embodiment 7) As shown in FIG. 13, an optical pickup device according to this embodiment includes a laser diode 181 as a light source and a collimator lens 19.
3. Polarizing beam splitter 182, quarter wave plate 18
4, a reflection hologram 200, a quarter-wave plate 186, an objective lens 187, a multi-lens 189, and a photodiode 190 as a photodetector.

The light splitting surface 183 of the polarizing beam splitter has a characteristic of reflecting S-polarized light and transmitting P-polarized light. The objective lens 187 is set so as to be compatible with the optical information recording medium 188. That is, the objective lens 187 is optimally designed so that the amount of spherical aberration becomes almost zero when a light beam enters the optical information recording medium 188. ing. The reflection type hologram 200 has a hologram area 201 shown by oblique lines in the center as shown in the configuration diagram of FIG.
And another area 202 formed of a flat reflector.
This reflection type hologram 200 has a hologram area 201.
The 0th-order diffracted light reflected by the hologram area and the + 1st-order diffracted light reflected by the hologram area are converted into parallel light, and the + 1st-order diffracted light reflected by the plane reflection plate 202 is converted into a light flux connecting the spot to 192 via the objective lens 187. Is set to

The operation of the optical pickup device according to the present embodiment will be described below. Assuming that the light beam from the laser diode 181 is S-polarized light whose polarization direction is perpendicular to the paper surface, the divergent emitted light beam is converted into parallel light after passing through the collimator lens 193. Then, the polarization beam splitter 182
Is reflected by the light dividing surface 183 formed in the direction of 45 degrees with respect to the optical axis, passes through the 波長 wavelength plate 184,
The light is reflected by the reflection hologram 200. Here, as described above, in the present embodiment, the + 1st-order diffracted light from the hologram region 201 of the reflection hologram 200 is given an aberration so as to form a spot on the optical information recording medium 192,
The 0th-order diffracted light from the hologram area 201 and the reflected light flux from the plane reflector 202 become parallel light and connect a spot to the optical information recording medium 188.

The light beam from the reflection type hologram 200 passes through the 波長 wavelength plate 184 and becomes P-polarized light. Then, the light passes through the light splitting surface 183 of the polarizing beam splitter, becomes circularly polarized by the ４ wavelength plate 186, and
A minute spot is formed on the optical information recording medium via the recording medium 87 to record, reproduce, and erase information. At this time, the 0-order diffracted light forms a spot on the optical information recording medium 188, and
The first-order diffracted light forms a spot on the optical information recording medium 192.

The reflected light from the optical information recording medium 188 and the optical information recording medium 192 passes through the quarter-wave plate 186 via the objective lens 187, and then becomes S-polarized light whose vibration direction is perpendicular to the plane of the paper. The light is reflected at a right angle by the light splitting surface 183 of the splitter, passes through the multi-lens 189, and enters the photodiode 190 as a photodetector. The information of the incident light in the photodiode 190 is converted into an electric signal to be a focus error signal and a tracking error signal, and is used as a reference for a servo operation by various servo mechanisms of the optical disk player.

Here, by limiting the hologram reflection area of the reflection type hologram 200 as shown in FIG. 14, the NA of the diffused light entering the objective lens 187 can be set smaller than the NA of the parallel light. . For example, the NA can be set to 0.45 for a so-called 1.2 mm-thick compact disc and 0.6 for a 0.6 mm-thick DVD.

The optical pickup device of the present embodiment having the above configuration can form spots on the optical information recording medium 188 and the optical information recording medium 192 at the same time and record the compatibility of the optical disc. In addition, the reproduced signal can be reliably maintained without deterioration. In addition, since the reflection hologram 200 is formed in a flat plate, it can be easily manufactured and can be manufactured precisely.

In the present embodiment, a collimator lens is provided between the laser diode and the polarization beam splitter to make parallel light before entering the polarization beam splitter. Further, a collimator lens is provided between the collimator lens and the polarization beam splitter. By arranging the shaping prism and expanding the beam, a good spot can be obtained on the optical information recording medium. At this time, the shaping prism may be joined to the polarizing beam splitter.

[0089]

In the optical pickup device of the present invention, a semi-reflective film is used, and a light beam transmitted through the semi-reflective film and a light beam reflected by the semi-reflective film are minutely placed on an optical disk having a different substrate thickness. An optical system is provided to form a spot. Therefore, the compatibility of the optical disk can be maintained without deteriorating the reproduction signal, and the reliability of the optical disk system can be greatly improved.

Further, by forming an optical pickup device using a polarizing beam splitter, a quarter-wave plate, a semi-reflective film, and a total reflection film, the optical pickup device can be made compact and lightweight and can cope with a plurality of optical disks having different thicknesses. Can be realized.

Furthermore, by making the semi-reflective film partially different in reflectivity and transmittance, the shape of the beam incident on the total reflective film can be adjusted, and the semi-reflective film reflects the total reflective film in the objective lens. The NA for the light beam can be set to a desired value.

Further, by providing a transmission hole at the center of the semi-reflective film and setting the reflected light beam from the total reflection film to pass through the transmission hole, it is possible to improve the light beam utilization efficiency. . Therefore, the compatibility of the optical disk can be reliably maintained without deteriorating the reproduction signal, and the utilization efficiency of the light beam can be increased.

Further, by providing a regulating member such that a light beam other than the central portion of the light beam transmitted through the semi-reflective film does not reach the optical disk, it is possible to optimize the numerical aperture of the light beam applied to the optical disk. Become.

Also, in the optical pickup device of the present invention,
By constructing an optical pickup device using a polarizing beam splitter, a quarter-wave plate, and a hologram element,
The light beam incident on the hologram element can be made compatible with optical disks having different substrate thicknesses by utilizing diffraction. Therefore, the compatibility of the optical disk can be reliably maintained without deteriorating the reproduction signal. Furthermore, since a flat optical disk can be used, manufacturing is easy and diffraction accuracy can be improved.

Further, by setting only a part of the hologram element as the hologram area and the other part as the total reflection area, it is possible to optimize the numerical aperture of the light beam irradiated on the optical disk.

Further, by integrally driving the objective lens and the polarizing beam splitter with the same actuator, the displacement of the center of the lens and the center of the optical axis due to the movement of the objective lens is eliminated, and the compatibility of the optical disk is recorded and reproduced. It can be maintained more reliably without deterioration.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an optical pickup device according to a first embodiment.

FIG. 2 is a schematic view showing a modified example of the optical pickup device of FIG.

FIG. 3 is an enlarged view showing an example in which a semi-reflective film and a reflective lens are integrated in the optical pickup device of FIG.

FIG. 4 is a schematic diagram showing another modified example of the optical pickup device of FIG. 1;

FIG. 5 is a schematic diagram illustrating a configuration of an optical pickup device according to a second embodiment.

FIG. 6 is a schematic diagram showing a modification of the optical pickup device of FIG.

FIG. 7 is a schematic diagram illustrating a configuration of an optical pickup device according to a third embodiment.

FIG. 8 is an enlarged view for explaining a means for reducing the numerical aperture.

FIG. 9 is a schematic diagram illustrating a configuration of an optical pickup device according to a fourth embodiment.

FIG. 10 is a schematic diagram illustrating a configuration of an optical pickup device according to a fifth embodiment.

FIG. 11 is a schematic view showing a modified example of the optical pickup device of FIG.

FIG. 12 is a schematic diagram illustrating a configuration of an optical pickup device according to a sixth embodiment.

FIG. 13 is a schematic diagram illustrating a configuration of an optical pickup device according to a seventh embodiment.

FIG. 14 is an enlarged view of the reflection hologram in FIG.

FIG. 15 is a schematic diagram showing a configuration of a conventional optical pickup device.

[Explanation of symbols]

1,51,91,151,391,891,991 Semi-reflective film 22,42,82,182,382,882,982
Polarizing beam splitter 24,44,84,184,384,884,984
λ / 4 plate 25, 45, 85, 385, 885, 985 Reflective lens 27, 47, 87, 187, 387, 887, 987
Objective lens 18, 28, 48, 52, 88, 92, 188, 19
2,388,392,888,892,988,992
Optical information recording medium

Continued on the front page (72) Inventor Takeshi Yamaguchi 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation

Claims (8)

[Claims] 1. An optical pickup device for recording and / or reproducing information by irradiating a plurality of types of optical disks having different substrate thicknesses with light beams, wherein a half of the light that transmits a part of incident light and reflects a part of the incident light is provided. A reflective film, and converting the light beam transmitted through the semi-reflective film into a light beam capable of forming a minute spot on an optical disk having a substrate thickness different from that of the light beam reflected by the semi-reflective film by giving an aberration to the light beam. An optical pickup device comprising: a total reflection film. 2. An optical pickup device for recording and / or reproducing information by irradiating a plurality of types of optical disks having different substrate thicknesses with a light beam, comprising: a light emitting source for irradiating linearly polarized light; A polarizing beam splitter for reflecting or transmitting polarized light, a quarter-wave plate arranged to receive a light beam reflected or transmitted by the polarizing beam splitter, and a part of a light beam transmitted through the quarter-wave plate A semi-reflective film that transmits light through the semi-reflective film and partially reflects the light to the quarter-wave plate; In order to form a minute spot on the lens, an aberration is given and
A total reflection film reflecting to a 波長 wavelength plate, a light beam reflected by the semi-reflection film, and a light beam reflected by the total reflection film via the 波長 wavelength plate and the polarizing beam splitter. An optical pickup device, comprising: an objective lens for condensing light. 3. The optical pickup device according to claim 1, wherein the semi-reflective film is formed so as to have partially different reflectance and transmittance. 4. The optical pickup device according to claim 1, wherein the semi-reflective film has a transmission hole in a central portion, and the total reflection film reflects into the transmission hole. An optical pickup device formed to guide a light beam. 5. The optical pickup device according to claim 1, wherein a regulating member that regulates a light beam other than a central portion of the light beam transmitted through the semi-reflective film so as not to be guided to the optical disk. An optical pickup device comprising: 6. An optical pickup device for recording and / or reproducing information by irradiating a plurality of types of optical disks having different substrate thicknesses with a light beam, wherein: a light emitting source for irradiating linearly polarized light; A polarizing beam splitter that reflects or transmits polarized light, a quarter-wave plate arranged to receive a light beam reflected or transmitted by the polarizing beam splitter, and diffracts a light beam transmitted through the quarter-wave plate. A reflection hologram element that reflects the light beam to the 波長 wavelength plate and a luminous flux reflected by the hologram element through the 波長 wavelength plate and the polarizing beam splitter. The hologram element is provided with a diffraction grating such that the light beam condensed by the objective lens forms a minute spot on an optical disc having a plurality of different substrate thicknesses. An optical pickup device, comprising: 7. The optical pickup device according to claim 6, wherein the hologram element includes a hologram region in a central portion,
An optical pickup device comprising a total reflection area of another portion. 8. The optical pickup device according to claim 2, wherein the objective lens and the polarization beam splitter are formed to be driven by the same actuator. .