JPH06231506A - Optical information recording / reproducing device, beam splitter, rising mirror - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the reflectance, the transmittance, or the generated phase difference from varying depending on the incident angle of the light beam incident on the beam splitter (BS) provided in the optical information recording / reproducing apparatus. To do. [Structure] The non-parallel light emitted from LD1 is emitted from the first BS2.
And is condensed on the disc 4 by the objective lens 3, and the reflected light from the disc 4 is the polarizing film 1 of the first BS 2.
Reflected by 1 and polarized and separated by the second BS 5
It is focused on D6 and D7. At this time, the first
BS for all incident angles of light incident on BS2
The reflectance, the transmittance, and the generated phase difference due to 2 do not vary.

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 and reproducing information on an optical information recording medium (hereinafter referred to as a disk), and optical parts such as a beam splitter and a rising mirror provided in the apparatus. Regarding

[0002]

2. Description of the Related Art A conventional optical information recording / reproducing apparatus having a beam splitter (hereinafter referred to as BS) arranged in a non-parallel optical path is constructed as shown in FIG. In FIG. 32, non-parallel light emitted from a light source (hereinafter, LD) 1 as a light emitting element passes through the first BS 2 and is focused on the disc 4 by the objective lens 3. The light reflected from the disk 4 is reflected by the first BS 2 and further polarized and separated by the second BS 5. The reflected light is a photodiode (hereinafter referred to as PD) as a first light receiving means for detecting a reproduction signal.
The transmitted light is focused on the PD 6, and the transmitted light is focused on the PD 7 as the second light receiving means for error detection. In the above structure, the light reflected from the disk 4 is incident on the first BS2 with an incident angle of a certain range of width, but conventionally, a difference occurs in the reflectance and the transmittance of the BS2 depending on the incident angle. No consideration was given to the fact that a phase difference occurs.

[0003]

As shown in FIG. 33, the conventional BS has a difference in transmittance and reflectance depending on the angle of incidence of light on the BS. For example, the light incident on the BS at an incident angle of 55 degrees has a higher reflectance than the light incident on the BS at an incident angle of 35 degrees, so that the intensity distribution of the light incident on the PD becomes non-uniform and the error signal becomes asymmetric. Or, the sensitivity decreases, which causes an offset. Further, the intensity distribution of the light that has passed through the BS and is incident on the disc is also non-uniform, so that the spot shape becomes asymmetric and the reproduced signal changes.

When the LD1 emits linearly polarized light, the reflectance Rp of the BS2 for the component of the polarization direction of this light is about 20%, and the BS of the component perpendicular to the polarization direction is BS.
It is assumed that the reflectance Rs of 2 satisfies the characteristic of about 100%. At this time, in the conventional BS, only the phase difference near the optical axis with an incident angle of 45 degrees was taken into consideration and the phase difference was suppressed to almost zero, but for the light with other incident angles, as shown in FIG. The generated phase difference was largely dependent on the incident angle. Therefore, there is a problem that a large phase difference occurs in the BS arranged in the non-parallel optical path.

That is, in the device shown in FIG. 32, the reproduction signal is such that the light polarized and separated by the second BS5 is received by the two PDs 6 and 7, respectively, and one PD6 detects B1p or B2p and the other PD7. By B1
s or B2s is detected. Then, the light B1 or B2 is detected by the difference signal of the signals detected by the two PDs 6 and 7. FIG. 35 shows a vector diagram of the lights B1 and B2 when passing through the second BS5 at this time. The vector A shown in FIG. 35 is the case where there is no phase difference in the incident angle.

When a phase difference occurs between the P-polarized light and the S-polarized light (birefringence of the disc or retardation due to an optical element), the incident light on the information signal detection system PBS becomes elliptically polarized light and the signal component And C / N deteriorate. This is shown in FIGS. 35 and 36.

The present invention has been made in view of such a situation, and is provided with a beam splitter in which reflectance, transmittance or generated phase difference does not depend on the incident angle of a light beam, and improves C / N. An object of the present invention is to provide an optical information recording / reproducing apparatus and an optical component thereof capable of achieving uniform intensity distribution of a light beam focused on a disc.

[0008]

According to a first aspect of the present invention, there is provided a disk 4 as an optical recording medium, an LD1 as a light emitting element for irradiating a light beam, and a disk 4 arranged in a diverging or converging optical path. BS2 and BS5 as beam splitters for separating the reflected light of PDs, and PD6 and PD7 as light receiving means for receiving the light transmitted or reflected by BS2,
In the optical information recording / reproducing apparatus equipped with
Polarizing films 11 and 12 as light separating films, in which variations in reflectance or transmittance at the time of separating light with respect to light having any incident angle incident on BS2 are within a range of 20% are formed. Is characterized by.

According to a second aspect of the present invention, an LD1 for irradiating a disk 4 with a light beam and a BS2 for separating reflected light from the disk 4 arranged in a diverging or converging optical path.
And PD that receives the light transmitted or reflected by BS2
In an optical information recording / reproducing apparatus including 6, 7,
BS2 has a P-polarization component and an S-polarization component which are generated when BS2 splits light with respect to light having any incident angle incident on BS2.
It is characterized in that the polarizing films 11 and 12 are formed such that the variation in the phase difference with the polarized component is within the range of 30 degrees.

According to a third aspect of the present invention, there is provided an LD1 for emitting a divergent light beam, and an objective lens 3 for collecting the emitted light beam from the LD1 on a disk 4 and receiving reflected light from the disk 4. , LD1 to the disc 4 by transmitting or reflecting the reflected light from the disc 4 arranged in the divergent light path between the LD 1 and the objective lens 3.
In an optical information recording / reproducing apparatus equipped with BS2 that separates from the optical axis of the light reaching up to, and PDs 6 and 7 that receives the light separated by BS2, BS2 converts light of any incident angle into BS2. On the other hand, the polarizing film 11 is characterized in that the dispersion of the reflectance or the transmittance when separating the light is within the range of 20%.

According to a fourth aspect of the present invention, an LD1 for emitting a divergent light beam, and an objective lens 3 for collecting the emitted light beam from the LD1 on a disk 4 and receiving reflected light from the disk 4 are provided. , LD1 to the disc 4 by transmitting or reflecting the reflected light from the disc 4 arranged in the divergent light path between the LD 1 and the objective lens 3.
In an optical information recording / reproducing apparatus equipped with BS2 that separates from the optical axis of the light reaching up to, and PDs 6 and 7 that receives the light separated by BS2, BS2 converts light of any incident angle into BS2. On the other hand, the light separation film is characterized in that the dispersion of the phase difference between the P-polarized component and the S-polarized component generated when the BS 2 separates the light is within the range of 30 degrees.

According to a fifth aspect of the present invention, there is provided an LD1 for emitting a divergent light beam, and an objective lens 3 for collecting the emitted light beam from the LD1 on a disk 4 and receiving reflected light from the disk 4. , LD1 to the disc 4 by transmitting or reflecting the reflected light from the disc 4 arranged in the divergent light path between the LD 1 and the objective lens 3.
In the optical information recording / reproducing apparatus provided with BS2 for separating from the optical axis of the light reaching to the optical path and PDs 6 and 7 for receiving the light separated by the BS2, the objective lens 3 is provided in the optical path from the L1 to the disk 4. Other than the optical element having a lens function other than the above, BS2 has a variation in reflectance or transmittance of 20% at the time of separating light with respect to light of any incident angle incident on BS2. Polarizing film 1
1 is formed.

According to a sixth aspect of the present invention, an LD1 for emitting a divergent light beam, and an objective lens 3 for collecting the emitted light beam from the LD1 on a disk 4 and receiving reflected light from the disk 4 are provided. , LD1 to the disc 4 by transmitting or reflecting the reflected light from the disc 4 arranged in the divergent light path between the LD 1 and the objective lens 3.
In the optical information recording / reproducing apparatus provided with BS2 that separates from the optical axis of the light that reaches the optical path and the PDs 6 and 7 that receives the light separated by the BS2, the objective lens 3 is provided in the optical path from the LD1 to the disk 4. BS2 does not include an optical element having a lens function other than the above, and the BS2 is arranged between the P-polarized component and the S-polarized component generated when the BS2 separates light with respect to light having any incident angle incident on the BS2. The polarizing film 11 having the dispersion of the phase difference in the range of 30 degrees is formed.

According to a seventh aspect of the present invention, an LD1 for irradiating the disk 4 with a light beam and a BS2 for separating the reflected light from the disk 4 arranged in a diverging or converging optical path.
And PD that receives the light transmitted or reflected by BS2
In an optical information recording / reproducing apparatus including 6, 7,
The PD 7 is divided by a dividing line 71 in the same direction as the S polarization direction of BS2.
The BS2 has a small variation in reflectance or transmittance with respect to the incident angle of incident light.

The present invention according to claim 8 is characterized in that it has a BS2 that simultaneously satisfies the features of claims 1 and 2, 3 and 4, or 5 and 6.

According to the ninth aspect of the present invention, the LD1 emits linearly polarized light, and the reflectance of BS2 is 10% or more and 40% or more for the component of the light emitted from the LD1 in the polarization direction.
In the following, the component perpendicular to the polarization direction of the light emitted from the LD1 is 50% or more.

According to the tenth aspect of the present invention, the LD1 emits linearly polarized light, and the reflectance of BS2 is 60% or more for the component in the polarization direction of the light emitted from the LD1.
% Or less, and 50% or less for the component perpendicular to the polarization direction of the light emitted from the LD1.

According to the present invention of claim 11, BS2 is
The polarization film 11 is formed so that the phase difference between the P-polarized component and the S-polarized component generated when the BS 2 separates the light is within ± 15 degrees with respect to the light having any incident angle incident on the BS 2. It is characterized by

According to a twelfth aspect of the present invention, an LD1 for emitting a light beam, an objective lens 3 for collecting a light beam emitted from the LD1 on a disc 4 and receiving reflected light from the disc 4 are provided. BS2, which is arranged in the divergent optical path between the LD1 and the objective lens 3, separates the reflected light from the disc 4 from the optical axis of the light from the LD1 to the disc 4 by transmitting or reflecting it, and the light separated by BS2 In the optical information recording / reproducing apparatus including BS5 that polarizes and separates the light and PDs 6 and 7 that have at least two light receiving portions that respectively receive the light beams that are polarized and separated by BS5, BS5 is incident on BS5 for all types. The polarizing film 12 is formed so that the dispersion of the reflectance or the transmittance at the time of separating the light with respect to the light of the incident angle is within the range of 20%. It is characterized in.

The present invention according to claim 13 relates to claim 1,
2, 3, 4, 5, 6, 7, 8, 9, 10, or BS5 according to claim 12, and BS5 according to claim 12 at the same time.

According to a fourteenth aspect of the present invention, there is provided an LD1 for emitting a light beam, an objective lens 3 for collecting a light beam emitted from the LD1 on a disc 4 and receiving reflected light from the disc 4, and an LD1. In an optical information recording / reproducing apparatus including a mirror 21 as a rising mirror arranged in a diverging or converging optical path between the objective lens 3 and the objective lens 3, and PDs 6 and 7 for receiving reflected light from the disk 4. A reflecting film is formed on the reflecting surface of the mirror 21 so that the reflectance when the mirror 21 reflects light is 95% or more for light of any incident angle entering the rising mirror. To do.

According to a fifteenth aspect of the present invention, an LD1 which emits a light beam, an objective lens 3 which collects the emitted light beam from the LD1 on a disc 4 and receives reflected light from the disc 4 are provided. A mirror 21 arranged in the divergent or convergent optical path between the LD 1 and the objective lens 3,
In the optical information recording / reproducing apparatus including PDs 6 and 7 that receive the reflected light from the disk 4, the mirror 21 emits light to the reflecting surface of the mirror 21 for all incident angles of light incident on the mirror 21. The dispersion of the phase difference between the P-polarized component and the S-polarized component generated when the light is reflected is 30
It is characterized in that a reflection film having a degree within a range is formed.

The present invention according to claim 16 provides the invention according to claim 14.
And a mirror 21 which simultaneously satisfies the features described in 15 and 15.

The present invention according to claim 17 relates to claim 1,
BS2 or BS5 according to any one of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13;
The mirror 21 according to any one of claims 14, 15 and 16 is provided at the same time.

The present invention according to claim 18 relates to BS2, B
S5 and the mirror 21 are characterized in that the reflectance, the transmittance, or the generated phase difference satisfies the characteristics described in each claim with respect to the range of variation and fluctuation of the wavelength of the light emitted from the LD1 of 30 nm. To do.

The present invention according to a nineteenth aspect is directed to an LD1 for emitting a light beam, an objective lens 3 for converging the light beam emitted from the LD1 on the disc 4 and receiving reflected light from the disc 4, and the LD1. And a mirror 21 arranged in a parallel or non-parallel optical path between the objective lens 3 and
BS2 which is arranged in the diverging or converging optical path and separates the reflected light from the disk 4, BS5 which polarizes and separates the light transmitted or reflected by BS2, and at least two light receiving devices which respectively receive the light beams polarized and separated by BS5 In the optical information recording / reproducing apparatus including the PDs 6 and 7 having parts, the phase difference between the P-polarized component and the S-polarized component with respect to BS2 is ± 15 immediately after the return light from the disc 4 exits BS2. The polarizing film 11 of BS2 and the reflecting film of the mirror 21 are formed so as to be within the degree.

The present invention according to claim 20 provides a mirror 21.
Causes the phase difference generated by the mirror 21 to cancel out the phase difference generated by the BS2.
It is characterized in that the phase difference between the P-polarized component and the S-polarized component with respect to BS2 immediately after the return light from B exits BS2 is within ± 15 degrees.

According to the twenty-first aspect of the present invention, the amount of change in the phase difference generated in the BS2 and the mirror 21 according to the twentieth aspect due to a predetermined wavelength variation is substantially the same for light of each incident angle. Is characterized by.

The present invention according to claim 22 is characterized in that the difference in the amount of change in the phase difference generated in the BS 2 and the mirror 21 according to claim 20 due to a predetermined wavelength fluctuation is ± 15 degrees with respect to light of each incident angle. It is characterized by being within.

According to the present invention of claim 23, BS2 is
In order to make the angular dependence of the reflectance or the transmittance almost zero, the phase difference is not set to almost zero, and the phase difference is equal to or more than a predetermined value.

According to a twenty-fourth aspect of the present invention, the BS2 and the mirror 21 are arranged such that the P-polarization directions thereof are the same, or one P-polarization direction and the other S-polarization direction are the same. Characterize.

The present invention according to claim 25 is characterized in that the angle dependency of the reflectance or the transmittance is substantially zero.

The present invention according to claim 26 is the BS2, B
The angle dependence of the phase difference between S5 and the P-polarized component and the S-polarized component of the mirror 21 is substantially zero.

The present invention according to claim 27, is BS2, B
S5 and the mirror 21 are within the range of the incident light of the light condensed by the objective lens 3 among the emitted light from the LD1 or the light received by the LD6, 7 among the returned light from the disk 4. On the other hand, it has the features described in each claim.

The present invention according to claim 28 is characterized in that the range of the incident angle is within ± 10 degrees with respect to the incident angle near the optical axis.

According to the 29th aspect of the present invention, BS 2 has a structure in which a first transparent member 2a and a second transparent member 2b are bonded together, and a polarization surface is formed on the bonding surface of the first transparent member 2a. The film 11 is formed, and the laminating surface of the first transparent member 2a on which the polarizing film 11 is formed and the second transparent member 2 are formed.
b has a structure in which it is bonded to the bonding surface of b via an adhesive layer 41. BS2 is the first transparent member 2a
S2 is arranged so as to face the side that reflects the return light from the disk 4, and the LDs 6 and 7 receive the light reflected by the BS 2 and detect at least a reproduction signal.

In the present invention according to claim 30, BS2 or BS5 is a flat plate-shaped transparent member made of a polarizing film 11 or 12.
Are formed.

The present invention according to claim 31 is characterized in that, out of the light emitted from LD1, the light reflected by BS2 is P
The light is received by D17, and BS2 is characterized by forming a reflective film so that the change in the amount of light incident on the PD17 due to the wavelength variation is within ± 10%.

In the thirty-second aspect of the present invention, the error signal is transmitted through the BS2 of the return light from the disk 4 to the LD1.
It is characterized in that the light traveling in the direction is detected by the PD 7 different from the PD 6.

The present invention according to claim 33 provides a disk 4
Converging light traveling in the direction of LD1 via BS2 among the returning light from B is focused on the focus error signal and tracking error signal detecting PD 7 using the hologram element 52.

According to a thirty-fourth aspect of the present invention, the material of the first or second transparent member 2a, 2b of the BS2 is 1.
It is characterized by being a material having a refractive index of 6 or more.

According to a thirty-fifth aspect of the present invention, the optical information recording / reproducing apparatus reproduces information from the disc 4 by detecting rotation of a polarization plane of a light beam generated by reflection on the disc 4. Is characterized by.

The present invention according to claim 36 provides a polarizing film 1
It is characterized in that 1, 12 or the reflection film is made of a birefringent substance.

The present invention according to claim 37 provides a polarizing film 1
1, 1 or the reflection film is characterized by being composed of a dielectric multilayer film.

The present invention according to claim 38 provides a polarizing film 1
1, 12 or the reflection film is composed of a multilayer film,
The number of films is 5 or more.

The present invention according to claim 39 provides a polarizing film 1
1, 12 or the reflection film is composed of a multilayer film,
It is characterized by including at least one layer of a metal thin film.

The present invention according to claim 40 is directed to claim 39.
The metal thin film 13 described in 1 above is a layer farthest from the first transparent member 2a.

The present invention according to claim 41 provides a polarizing film 1
1, 12 or the reflection film is composed of a multilayer film,
It is characterized by being made of at least four kinds of materials.

The present invention according to claim 42 provides a polarizing film 1
1, 12 or the reflection film is composed of a multilayer film,
It is characterized by including an extremely thin layer.

The present invention according to claim 43 provides the invention according to claim 42.
The extremely thin layer described in (1) is characterized in that the optical film thickness is 1/10 or less of the wavelength.

The present invention according to claim 44 provides a polarizing film 1
1, 12 or the reflection film is composed of a multilayer film,
At least one layer containing Hf or an oxide of Hf as a main component is included.

The present invention according to claim 45 provides a polarizing film 1
1, 12 or the reflection film is composed of a multilayer film,
It is characterized in that at least one layer containing Zr or an oxide of Zr as a main component is included.

The present invention according to claim 46 provides a billing contract 44.
Alternatively, the layer containing the material described in 45 as a main component is a layer farthest from the first transparent member 2a. .

The 47th aspect of the present invention is characterized in that the first transparent member 2a contains at least Si and Pb.

The present invention according to claim 48 provides a polarizing film 1
1, 12 or the reflection film is composed of a multilayer film,
The layer in contact with the first transparent member 2a is characterized by containing Pb.

The present invention according to claim 49 provides the invention according to claim 29.
The adhesive layer 41 described in 1 above is characterized in that the physical and optical characteristics do not change in an environment of 100 ° C. or higher.

The present invention according to claim 50 is directed to claim 1,
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13,
17, 18, 19, 21, 22, 23, 24, 25, 2
6, 27, 28, 29, 30, 31, 32, 33, 3
4, 35, 36, 37, 38, 39, 40, 41, 4
BS2 having the characteristics set forth in 2, 43, 44, 45, 46, 47, 48 or 49.

The present invention according to claim 51 is directed to claim 1
2, 13, 17, 18, 25, 26, 27, 28, 3
BS5 having the characteristics according to 0, 35, 36, 37 or 38.

The present invention according to claim 52 provides the invention according to claim 1.
4, 15, 16, 17, 18, 19, 20, 23, 2
4, 25, 26, 27, 28, 35, 36, 37, 3
8, 39, 40, 41, 42, 43, 44, 45, 4
A mirror 21 having the features described in 6, 47 or 48.

[0060]

In the optical information recording / reproducing apparatus and the optical parts thereof having the above structure, the disk 1 is irradiated with a light beam L.
BS2 and 5 are provided in the optical path of D1, and the reflected light from the disk 1 is transmitted or reflected by BS2 and 5, and PD6,
7, BS 2 and 5 are provided with polarizing films 11 and 12, respectively, so that the reflectance, the transmittance, or the transmittance at the time of separating the light with respect to light of any incident angle incident on BSs 2 and 5 or Since the dispersion of the generated phase difference is reduced, it is possible to reduce the offset of the received light amount in the PDs 6 and 7, improve the C / N, and make the intensity distribution of the light beam focused on the disk 4 uniform. You can

[0061]

Embodiments of the optical information recording / reproducing apparatus and its optical components of the present invention will be described below with reference to the drawings. In each of the following embodiments, the parts corresponding to those in the conventional case are designated by the same reference numerals, and the description thereof will be omitted as appropriate.

1 to 3 show the configuration of the first embodiment of the present invention. The feature of this embodiment is that the first BS 2 is formed by adhering the first transparent member 2a and the second transparent member 2b through the polarizing film 11 as the light separation film having the characteristics shown in FIG. In point. Another point is that the second BS 5 is formed of a flat plate-shaped transparent member, and the polarizing film 12 having the characteristics shown in FIG. 3 is formed on the surface. As shown in FIG. 3, the characteristic of the polarizing film 12 is that the incident angle is about 35 degrees with respect to the reflectance of the P component and S component light at an incident angle of 45 degrees, as shown by the thin lines 13 and 14 in FIG. There is a point that the change in reflectance is within ± 10% even if it changes from to 55 degrees.

According to the present embodiment, even if the incident angle of the light incident on the BSs 2 and 5 changes, the reflectances are almost the same, so PD
The intensity distributions of the light focused on 6 and 7 and the light focused on the disk 4 become uniform. In addition, since the light transmittance of the second BS 5 can be made equal regardless of the incident angle, no offset is applied on the divided PDs 6 and 7.

In the second embodiment of the present invention, in the device configuration shown in FIG. 1, the characteristics of the polarizing films 11 and 12 are, as shown in FIG. 4, the phase difference shown by the dotted line is always zero even if the incident angle changes. To be close to. As a result, it is possible to prevent a decrease in C / N due to the phase difference. In this case, PD6,
It is known that assuming that the phase difference of the light entering 7 is δ degrees, the C / N is reduced by 20 × log cos δ (dB).

In the third embodiment of the present invention, in the apparatus configuration shown in FIG. 1, as shown in FIG. 5, a rising reflection mirror (hereinafter referred to as a mirror) is set on the optical path between the first BS 2 and the objective lens 3. 21 is provided and the optical axis of the objective lens 3 is bent in a direction perpendicular to the optical axis of BS2. Then, the relationship between the phase difference and the incident angle generated when the return light from the disk reflects the first BS2 is made to have the characteristics shown in FIG. In this case, even if the difference between the phase of S-polarized light and the phase of P-polarized light with respect to the first BS2 is 50 degrees, a phase difference of 50 degrees occurs almost uniformly regardless of the incident angle. Therefore, by forming a film on the reflecting film of the mirror 21 so that the difference between the phase of S-polarized light and the phase of P-polarized light is 50 degrees, the P-direction of BS2 and the S-direction of the mirror 21 are the same. Therefore, the two cancel each other out of the phase difference.

The phase difference after cancellation is 1 even if it is 0 degree.
Even at 80 degrees, C / N does not deteriorate immediately after exiting the BS, because it is linearly polarized light.

Next, as shown in FIG. 6, the P direction of BS2 and the P direction of the mirror 21, or the S direction of BS2 and the mirror 2
In the configuration where the S direction of 1 has the same arrangement,
As shown in FIG. 8, by designing the reflection film of the mirror 21 such that the difference between the phase of P-polarized light and the phase of S-polarized light is 50 degrees, the phase difference C generated between the BS 2 and the mirror 21 is C. , D will cancel each other out.

In the third embodiment shown in FIG. 5, an optical element having a lens function other than the objective lens 3 is not provided in the optical path from the LD 1 to the disk 4, and a finite optical system is constructed. In the fourth embodiment shown in FIG. 9, the first BS2
The collimator lens 31 is provided in the optical path between the mirror 21 and the mirror 21, and constitutes an infinite optical system. In the configuration shown in FIG. 9, it is assumed that the first BS 2 has the characteristics shown in FIG. At this time, the collimator lens 31 is attached to the mirror 21.
The light that has become parallel light is incident on the mirror 21. Therefore, in order to correct the phase difference generated by BS2, the mirror 21
The reflective film may be designed such that the difference between the phase of S-polarized light and the phase of P-polarized light becomes 50 degrees at an incident angle of 45 degrees.

The fifth embodiment of the present invention shown in FIG.
The light emitted from D1 is reflected at a right angle by the first BS2 and condensed on the disc through the objective lens 3, and the reflected light from the disc is passed through the objective lens 3, the first BS2 and the second BS5. The light is condensed on the PDs 6 and 7. Also in this case, by providing the polarizing films 11 and 12 having the characteristics shown in the above-described embodiments on the BSs 2 and 5,
The same effect can be obtained.

Next, the configuration of the sixth embodiment of the present invention is shown in FIG.
And FIG. 12 will be described. In the prism type BS2, the amount of phase difference generated varies depending on the incident direction of light. 11 is a plan view of FIG. 1, and FIG. 12 is a configuration diagram of the prism type BS2. In FIG. 12, the polarizing film 11 is vapor-deposited on the bonding surface of the first transparent member 2 a having a triangular prism shape, and the bonding surfaces of the two transparent members 2 a and 2 b are bonded via the adhesive layer 41. . When the light is incident from the two sides of the second transparent member 2b which are orthogonal to each other, the light passes through the adhesive layer 41, is reflected by the polarizing film 11, and again passes through the adhesive layer 41 to be emitted from BS2. The generated phase difference largely depends on the incident angle. This is because the optical path length passing through the adhesive layer 41 at the time of reflection changes depending on the incident angle, and it is difficult to control the thickness of the adhesive layer 41 with high accuracy.

On the other hand, when the light enters from the two sides of the first transparent member 2a which are orthogonal to each other, the light is reflected only by the polarizing film 11, so that the control of the phase difference becomes relatively easy. Therefore, as shown in FIG. 11, the objective lens 3 is provided on the side of the first transparent member 2a on which the polarizing film 11 having the characteristics shown in Examples 2 to 4 is deposited.
And the second transparent member 2b side is placed on the LD1 side.

In the seventh embodiment of the present invention shown in FIGS. 13 and 14, the PD 6 for detecting the reproduction signal in which the phase difference causes a problem is reflected by the first BS 2 of the return light from the disk 4. The received light is received. Then, the PD 7 for detecting the focus error signal and the tracking error signal is provided on the substrate 51 supporting the LD 1, and the hologram 52 is arranged on the optical path connecting the LD 1 and the first BS 2 so that the return light from the disk 4 The light transmitted through the first BS2 is focused on the PD 7 via the hologram 52.

According to the present embodiment, the error detection can be detected by the light that does not depend on the polarization direction of the return light, and the LD1 and PD7 can be integrated so that the adjustment can be facilitated.

In the eighth embodiment of the present invention shown in FIG. 15, the first BS 2 is formed in a plate shape.

In the ninth embodiment of the present invention shown in FIG. 16, the first BS2 has a plate shape and the second BS5 has a prism shape.

The tenth embodiment of the present invention shown in FIG.
The prism material of BS2 is SF-110 with a refractive index of 1.77.
It is what When the refractive index is 1.7, for example, the angle of refraction θ2 is reduced to about 40% to 60% with respect to the angle of incidence θ1, and the dependency of the angle of incidence θ1 on the characteristics of the polarizing film can be reduced. Design becomes easy.

The eleventh embodiment of the present invention shown in FIG.
Since the PD 17 for monitoring the light intensity does not have a phase difference in the incident light, the light emitted from the LD 1 is reflected by the polarizing film 11 of the first BS 2 and the reflected light is condensed on the PD 7 as shown in FIG. It is configured to allow. The reflected light from the disc, which has a problem of phase difference, is reflected by the polarizing film 11 and is condensed on the reproduction signal detecting PD 6 via the second BS 5. At this time, with respect to the amount of light received by the PD 7, the polarizing film 11 of the first BS 2 is designed so that the variation of the amount of light exceeding ± 10% does not occur due to the wavelength variation.

In the twelfth embodiment of the present invention shown in FIGS. 20 and 21, the reflectance, transmittance and phase difference of BS2, 5 and mirror 21 are about 30 nm of the oscillation wavelength of LD1 as shown in FIG. The film is designed to be almost constant in the wavelength range of. Here, the oscillation wavelength of the LD1 changes depending on the temperature as shown in FIG. 21, but by performing the film design as described above, the polarization film characteristics hardly change in the operating temperature range of the LD1. The phase difference changes depending on the wavelength when the incident angle is 45 degrees, 55 degrees, and 35 degrees, as shown in FIGS. 22 (a), (b), and (c). In FIG. 22, the line 61 indicates the amount of phase change of the S component, the line 62 indicates the amount of phase change of the P component, and the difference therebetween is the phase difference.

The thirteenth embodiment of the present invention shown in FIG. 23 is
The reflectance of BS5 is the angle of incidence of the return light from the disk 4 so that a good error signal with a small offset can be detected in the two light-receiving parts that are divided into two in the S-polarization direction via the dividing line 71 of the PD7. The polarizing film is configured so as not to depend on

In the fourteenth embodiment of the present invention shown in FIGS. 24 and 25, in the device configuration shown in FIG. 1, the linearly polarized light in the P direction emitted from the LD1 as shown in FIG. For the component, the reflectance reflected by BS2 should be 10% or more and 40% or less, and for the component in the direction perpendicular to the polarization direction, the reflectance should be 50% or more.
The reflectance characteristic of the polarizing film 11 of S2 is configured.

In the fifteenth embodiment of the present invention shown in FIGS. 26 and 27, in the device configuration shown in FIG. 10, the direction of polarization of the linearly polarized light in the P direction emitted from LD1 as shown in FIG. For the component, the reflectance reflected by BS2 is 60% or more and 90% or less, and for the component in the direction perpendicular to the polarization direction, the reflectance is 50% or more,
The reflectance characteristic of the polarizing film 11 of BS2 is configured.

28 and 29 show changes in the polarization state in BS2. When the amplitude of the light incident on BS2 is A, the power of the incident light is A2. In BS2 in which the reflectance Rp for S-polarized light is 1 or less when the reflectance Rs for S-polarized light is 1, as shown in FIG. 28, the light passes through BS2 to reach the disc 4 and is reflected from the disc 4 to BS2. The power of the incident light that enters is A2 (1-Rp). BS
The power of the emitted light reflected by 2 and emitted to the LD side is A
2 (1-Rp) Rp. At this time, as shown in FIG. 29, when Rp becomes smaller, the apparent Kerr rotation angle is amplified and changes from φ to φ ′.

Of the phase differences generated in each of the above embodiments, the phase difference generated only by the return light 81 from the disk 4 being reflected by the polarizing film 11 of BS2 as shown in FIG. 30 is incident on BS2. The total phase difference is set to be within 15 degrees when light of all incident angle components is taken into consideration. Also, as shown in FIG. 31, the return light 81 is P
When there are a plurality of elements that generate a phase difference, such as the mirror 21 and the first BS2, in the path up to D6 and D7, the sum of the phase differences generated by each element is 1
Be within 5 degrees.

In the structure in which the phase difference is canceled by the BS 2 and the mirror 21, the phase difference generated in both elements changes depending on the wavelength of the incident light, but the wavelength dependence is the same in both elements. (Fig. 32
(A), (b)), the phase difference when the return light exits the beam splitter is not affected by the wavelength variation of the light.

Further, the polarizing films 11 and 1 shown in each of the above embodiments.
2 or the reflective film is composed of a birefringent material, a dielectric multilayer film, a multilayer film of five layers or more, and the like.

In the production of the beam splitter, it is difficult to set the angle dependence and the wavelength dependence of the reflectance or the transmittance to almost 0 and the phase difference to 0, but there is some phase difference (for example, It is not so difficult to obtain a material that does not have the above dependency in a BS (50 degrees), so that the degree of freedom in designing and manufacturing is widened, which leads to cost reduction.

In the sixteenth embodiment of the present invention shown in FIGS. 33 and 34, when the polarizing film 11 or the reflecting film is composed of a dielectric multilayer film, the first embodiment is provided to protect the dielectric film. The metal thin film 13 is laminated on the layer farthest from the transparent member 2a. The metal thin film 13 prevents the dielectric film from having unstable optical characteristics with respect to water in the adhesive or water vapor in the atmosphere.

The seventeenth embodiment of the present invention shown in FIGS. 35 and 36 is an example of designing and manufacturing the polarizing film 11, and the multilayer film is H.
fO2 layer 11a, Al2O3 layer 11b, TiO2 layer 11c,
It is composed of four types of layers of the MgF2 layer 11d. HfO2 or Hf which is not usually used for wavelengths other than the ultraviolet region is used, but ZrO2 or Zr may be used.

As the structure of the multilayer film, HfO 2 is laminated on the layer farthest from the first transparent member 2a, and the optical film has an optical film thickness (refractive index of the film is n, light propagates in the film) in the multilayer film. Distance d
Is represented by nd) as λ / 10 or less.

Further, the first transparent member 2a has PbO, S
SF-based glass containing iO2 as a main component is used, and the layer in contact with the substrate is TiO2 and Pb in the first transparent member 2a.
Are mixed together. FIG. 36 shows a 13-layer structure, and the approximate geometric film thickness of each layer is the same as that of the first transparent member 2a.
From the side, 110 nm, 170 nm, 80 nm, 80
nm, 300 nm, 80 nm, 110 nm, 180 n
m, 130 nm, 190 nm, 80 nm, 130 nm,
20 nm and 90 nm.

First transparent member 2a and second transparent member 2b
When the adhesive is adhered via the polarizing film 11, an adhesive having excellent environmental resistance can be obtained by using an adhesive that does not change the physical and optical characteristics even in an environment of 100 ° C. or higher.

[0092]

As described above, according to the optical information recording / reproducing apparatus and the optical parts thereof of the present invention, the reflectance, the transmittance or the phase difference generated in the non-parallel optical path depends on the incident angle of the light beam. Since the independent beam splitter is arranged and the beam splitter splits the non-parallel light, the phase difference can be reduced and the C / N can be improved. Further, the offset of the amount of received light in the light receiving element is reduced, the intensity of the light beam focused on the optical information recording medium is evenly distributed, and the design of the finite optical system optical information recording / reproducing apparatus is facilitated. You can

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a diagram showing the relationship between the incident angle and the reflectance of the BS according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between an incident angle of BS and a phase difference according to the second embodiment of the present invention.

FIG. 5 is a perspective view showing a configuration of a third exemplary embodiment of the present invention.

FIG. 6 is a plan view of FIG.

FIG. 7 is a diagram showing a relationship between an incident angle on a BS and a phase difference according to the third embodiment of the present invention.

FIG. 8 is a diagram showing a phase difference caused by a BS and a phase difference caused by a mirror in the third embodiment of the present invention.

FIG. 9 is a perspective view showing a configuration of a fourth exemplary embodiment of the present invention.

FIG. 10 is a perspective view showing a configuration of a fifth exemplary embodiment of the present invention.

FIG. 11 is a plan view showing a configuration of a sixth exemplary embodiment of the present invention.

12 is an explanatory diagram showing the configuration of the BS of FIG.

13 is a plan view showing the configuration of the embodiment of FIG. 7 of the present invention. FIG.

FIG. 14 is an explanatory diagram showing the configuration of the BS of FIG.

FIG. 15 is a plan view showing the configuration of the eighth exemplary embodiment of the present invention.

FIG. 16 is a plan view showing the configuration of the ninth exemplary embodiment of the present invention.

FIG. 17 is an explanatory diagram showing a structure of a BS according to a tenth embodiment of the present invention.

FIG. 18 is a plan view showing the structure of an eleventh embodiment of the present invention.

FIG. 19 is an explanatory diagram showing the structure of the BS of FIG. 18.

FIG. 20 is a diagram showing a relationship between an oscillation wavelength of an LD and reflectance and transmittance of BS according to a twelfth embodiment of the present invention.

FIG. 21 is a diagram showing the relationship between the oscillation wavelength of an LD and temperature.

FIG. 22 is a diagram showing the relationship between the oscillation wavelength of the LD, the angle of incidence on the BS, and the phase difference.

FIG. 23 is a perspective view showing the configuration of a thirteenth embodiment of the present invention.

FIG. 24 is a perspective view showing the structure of a fourteenth embodiment of the present invention.

FIG. 25 is a diagram showing the relationship between the incident angle of BS and the reflectance according to the fourteenth embodiment of the present invention.

FIG. 26 is a perspective view showing the configuration of a fifteenth embodiment of the present invention.

FIG. 27 is a diagram showing the relationship between the incident angle and the reflectance of BS according to the fifteenth embodiment of the present invention.

FIG. 28 is an explanatory diagram showing the relationship between the amplitude of incident light on a BS and the power of incident light and the power of outgoing light.

FIG. 29 is a diagram illustrating a change in polarization state in BS.

FIG. 30 is an explanatory diagram of a case where a phase difference is generated only by BS.

FIG. 31 is an explanatory diagram when a phase difference is generated by a plurality of elements.

32 is a diagram showing the relationship between the wavelength of LD and the phase difference generated in BS2 and mirror 1. FIG.

FIG. 33 is an explanatory diagram illustrating a sixteenth embodiment of the present invention.

FIG. 34 is an explanatory diagram illustrating a case of the mirror 21 according to the sixteenth embodiment of the present invention.

FIG. 35 is an explanatory diagram illustrating a seventeenth embodiment of the present invention.

FIG. 36 is an explanatory diagram illustrating a seventeenth embodiment of the present invention.

FIG. 37 is an explanatory diagram showing a configuration of an example of a conventional optical information recording / reproducing apparatus.

38 is a diagram showing the relationship between the incident angle of the BS shown in FIG. 32 and the transmittance and reflectance.

39 is a diagram showing the relationship between the incident angle of the BS shown in FIG. 32 and the generated phase difference.

FIG. 40 is a diagram showing a vector of light passing through the second BS shown in FIG. 32.

41 is a diagram showing a vector when a phase difference of light occurs in the vector diagram shown in FIG. 35.

[Explanation of symbols]

 1 LD (Light Emitting Element) 2 First BS (Beam Splitter) 3 Objective Lens 4 Disk (Optical Recording Medium) 5 Second BS (Beam Splitter) 6, 7 PD (Light Receiving Element) 11, 12 Polarizing Film (Light Separation) Film) 13 Metal thin film 21 Mirror (start-up mirror) 41 Adhesive layer 52 Hologram element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hayami Hosokawa 10 Odoron-cho, Hanazono Tadodo-cho, Ukyo-ku, Kyoto City, Kyoto Prefecture OMRON Corporation

Claims (52)

[Claims] 1. A light emitting element for irradiating a light beam to an optical recording medium, a beam splitter arranged in a diverging or converging optical path for separating reflected light from the optical recording medium, and light transmitted or reflected by the beam splitter. In the optical information recording / reproducing apparatus including: a light receiving unit for receiving the light, the beam splitter has a variation in reflectance or transmittance when separating the light with respect to light having any incident angle entering the beam splitter. The optical information recording / reproducing apparatus is characterized in that a light separation film having a ratio of 20% is formed. 2. A light emitting element for irradiating a light beam onto an optical recording medium, a beam splitter arranged in a divergent or convergent optical path for separating reflected light from the optical recording medium, and transmitted or reflected through the beam splitter. In the optical information recording / reproducing apparatus including: a light receiving unit that receives the emitted light, the beam splitter is generated when the beam splitter separates the light with respect to light having any incident angle that is incident on the beam splitter. An optical information recording / reproducing apparatus, characterized in that a light separation film having a variation in phase difference between the P-polarized component and the S-polarized component within a range of 30 degrees is formed. 3. A light emitting element that emits a divergent light beam, an objective lens that collects the light beam emitted from the light emitting element on an optical recording medium, and receives reflected light from the optical recording medium, and the light emission. A beam splitter arranged in a divergent light path between the element and the objective lens, for separating or reflecting the reflected light from the optical recording medium from the optical axis of the light reaching the optical recording medium from the light emitting element; An optical information recording / reproducing apparatus comprising: a light receiving unit that receives the light separated by the beam splitter, wherein the beam splitter separates the light with respect to light having any incident angle incident on the beam splitter. The optical information recording / reproducing apparatus is characterized in that a light separation film having a variation in reflectance or transmittance of 20% is formed. . 4. A light emitting element that emits a divergent light beam, an objective lens that collects a light beam emitted from the light emitting element onto an optical recording medium, and receives reflected light from the optical recording medium; A beam splitter disposed in a divergent light path between the element and the objective lens, and separating or separating the reflected light from the optical recording medium from the optical axis of the light reaching the optical recording medium from the light emitting element, In an optical information recording / reproducing apparatus including: a light receiving unit that receives the light separated by the beam splitter, the beam splitter separates the light with respect to light of any incident angle that enters the beam splitter from the light emitting element. Forming a light separation film in which the dispersion of the phase difference between the P-polarized component and the S-polarized component generated at the time is within the range of 30 degrees. An optical information recording / reproducing apparatus characterized by: 5. A light emitting element that emits a divergent light beam, an objective lens that collects the light beam emitted from the light emitting element onto an optical recording medium, and receives reflected light from the optical recording medium, and the light emission. A beam splitter disposed in a divergent light path between the element and the objective lens, and separating or separating the reflected light from the optical recording medium from the optical axis of the light reaching the optical recording medium from the light emitting element, In the optical information recording / reproducing apparatus including: a light receiving unit that receives the light separated by the beam splitter, the beam splitter includes an optical element other than the objective lens in an optical path from the light emitting element to the optical recording medium. The beam splitter does not include an optical element having a lens function, and the beam splitter is effective for all incident angles of light incident on the beam splitter. The optical information recording and reproducing apparatus characterized by variations in the reflectance or transmittance at the time of separating the light forms a beam splitting film is in the range of 20%. 6. A light emitting element that emits a divergent light beam, an objective lens that collects a light beam emitted from the light emitting element onto an optical recording medium, and receives reflected light from the optical recording medium, and the light emission. A beam splitter disposed in a divergent light path between the element and the objective lens, and separating or separating the reflected light from the optical recording medium from the optical axis of the light reaching the optical recording medium from the light emitting element, An optical information recording / reproducing apparatus comprising: a light receiving means for receiving the light separated by the beam splitter; and an optical information recording / reproducing apparatus having a lens function other than the objective lens in an optical path from the light emitting element to the optical recording medium. Since the beam splitter has no element, the beam splitter emits light for all incident angles of light incident on the beam splitter. The optical information recording and reproducing apparatus characterized by variations in the phase difference forms a light separation film is in the range of 30 degrees between the P-polarized component and S-polarized light component generated upon release. 7. A light emitting element for irradiating a light beam to an optical recording medium, a beam splitter arranged in a diverging or converging optical path for separating reflected light from the recording medium, and a light transmitted or reflected by the beam splitter. In the optical information recording / reproducing device including a light receiving unit for receiving light, the light receiving unit has a dividing line in the same direction as the S polarization direction of the beam splitter, and the beam splitter has an incident angle of incident light. On the other hand, an optical information recording / reproducing apparatus characterized in that variations in reflectance or transmittance are small. 8. Claims 1 and 2, 3 and 4, or 5 and 6
An optical information recording / reproducing apparatus having a beam splitter which simultaneously satisfies the characteristics described in 1. 9. The light emitting element emits linearly polarized light,
The reflectance of the beam splitter is 10% or more and 40% or less for a component in the polarization direction of light emitted from the light emitting element, and 50% or more for a component perpendicular to the polarization direction of the light emitted from the light emitting element. 9. The optical recording / reproducing apparatus according to any one of claims 1, 3, 5, 7 or 8. 10. The light emitting element emits linearly polarized light, and the reflectance of the beam splitter is 60% or more and 90% or less for a component of the polarization direction of the light emitted from the light emitting element. 9. The optical recording / reproducing apparatus according to claim 1, wherein the component perpendicular to the polarization direction of the light emitted from is 50% or less. 11. The beam splitter has a phase difference between a P-polarized component and an S-polarized component generated when the beam splitter separates light with respect to light of any incident angle incident on the beam splitter. 9. The optical information recording / reproducing apparatus according to claim 2, wherein a light separation film having an angle of 15 degrees or less is formed. 12. A light emitting element that emits a light beam, an objective lens that collects a light beam emitted from the light emitting element onto an optical recording medium, and receives reflected light from the optical recording medium, and the light emitting element. A beam splitter disposed in a divergent light path between the objective lens and the objective lens to separate or separate the reflected light from the optical recording medium from the optical axis of the light from the light emitting element to the optical recording medium, A polarization beam splitter that polarizes and separates the light separated by the beam splitter, and a light receiving unit that has at least two light receiving portions that respectively receive the light beams polarized and separated by the polarization beam splitter, and optical information recording / reproducing In the device, the polarization beam splitter is adapted to receive light of any incident angle which is incident on the polarization beam splitter. The optical information recording and reproducing apparatus characterized by reflectance or transmittance at the time of separating the light forms a beam splitting film is in the range of 20%. 13. The method according to claim 1, 2, 3, 4, 5, 6, 7,
13. An optical information recording / reproducing apparatus having the beam splitter according to any one of 8, 9, 10 and 11 and the polarization beam splitter according to claim 12 at the same time. 14. A light emitting element that emits a light beam, an objective lens that collects a light beam emitted from the light emitting element on an optical recording medium, and receives reflected light from the optical recording medium, and the light emitting element. In the optical information recording / reproducing apparatus, a raising mirror arranged in a diverging or converging optical path between the objective lens and the objective lens, and a light receiving means for receiving reflected light from the optical recording medium are provided. A reflecting film is formed on the reflecting surface of the mirror so that the reflectance when the rising mirror reflects light is 95% or more for light of any incident angle entering the rising mirror. Optical information recording / reproducing device. 15. A light emitting element that emits a light beam, an objective lens that collects a light beam emitted from the light emitting element onto an optical recording medium, and receives reflected light from the optical recording medium, and the light emitting element. In the optical information recording / reproducing apparatus, a raising mirror arranged in a diverging or converging optical path between the objective lens and the objective lens, and a light receiving means for receiving reflected light from the optical recording medium are provided. On the reflection surface of the mirror, the variation in the phase difference between the P-polarized component and the S-polarized component generated when the rising mirror reflects light with respect to light having any incident angle to the rising mirror is 30. An optical information recording / reproducing apparatus having a reflection film formed within a range of degrees. 16. An optical information recording / reproducing apparatus having a raising mirror that simultaneously satisfies the features of claims 14 and 15. 17. The method according to claim 1, 2, 3, 4, 5, 6, 7,
The beam splitter or the polarization beam splitter according to any one of 8, 9, 10, 11, 12 and 13 and the rising mirror according to any one of claims 14, 15 and 16 at the same time. Optical information recording / reproducing device. 18. The beam splitter, the polarization beam splitter, and the raising mirror have a reflectance, a transmittance, or a generated phase difference within a range of wavelength variation and fluctuation amount of light emitted from the light emitting element. On the other hand, the characteristics described in each claim are satisfied,
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13. The optical information recording / reproducing apparatus according to any one of 13, 14, 15, 16 or 17. 19. A light emitting element that emits a light beam, an objective lens that collects the light beam emitted from the light emitting element onto an optical recording medium, and receives reflected light from the optical recording medium, and the light emitting element. And the objective lens, a raising mirror arranged in a parallel or non-parallel optical path, a beam splitter arranged in a diverging or converging optical path to separate reflected light from the optical recording medium, and a beam splitter that transmits the beam splitter. Alternatively, in the optical information recording / reproducing apparatus, a polarization beam splitter that polarizes and separates the reflected light; and a light receiving unit that has at least two light receiving portions that respectively receive the light beams that are polarized and separated by the polarization beam splitter, Immediately after the return light from the optical recording medium exits the beam splitter, The light separation film of the beam splitter and the reflection film of the rising mirror are formed so that the phase difference between the P-polarized component and the S-polarized component is within ± 15 degrees or within 180 degrees ± 15 degrees. Optical information recording / reproducing device. 20. Immediately after the returning light from the optical recording medium exits the beam splitter, the rising mirror cancels the phase difference generated by the beam splitter by the phase difference generated by the rising mirror. 20. The optical information recording / reproducing apparatus according to claim 19, wherein the phase difference between the P-polarized component and the S-polarized component with respect to the beam splitter is within ± 15 degrees or within 180 degrees ± 15 degrees. 21. The amount of change in the phase difference generated in the beam splitter and the raising mirror due to a predetermined wavelength variation is substantially the same for light of each incident angle. Optical information recording and reproducing device. 22. The difference in the amount of change in the phase difference generated by the beam splitter and the raising mirror due to a predetermined wavelength fluctuation is within ± 15 degrees with respect to light of each incident angle. Item 22. The optical information recording / reproducing apparatus according to Item 21. 23. In order to make the angle dependence of the reflectance or the transmittance of the beam splitter almost zero,
23. The phase difference is not substantially 0, and has a phase difference of a predetermined value or more, 23, 21 or 22.
The optical information recording / reproducing apparatus described in 1. 24. The beam splitter and the rising mirror are arranged such that their P-polarization directions are the same or one P-polarization direction and the other S-polarization direction are the same. Claims 19, 20, 2
The optical information recording / reproducing apparatus described in 1, 22, or 23. 25. The angle dependence of the reflectance or the transmittance is substantially 0,
5, 7, 8, 9, 10, 12, 13, 14, 16, 17
Or the optical information recording / reproducing apparatus according to any one of 18). 26. The angle dependence of the phase difference between the P-polarized component and the S-polarized component of the beam splitter, the polarization beam splitter, and the raising mirror is substantially zero. 2, 4, 6, 8, 1
1, 13, 15, 16, 17, 18, 19, 20, 2
1. The optical information recording / reproducing apparatus according to any one of 1, 22, 23, 24 and 25. 27. The beam splitter, the polarization beam splitter, and the raising mirror are light emitted from the light emitting element, which is condensed by an objective lens,
Alternatively, among the returned light from the optical recording medium, the light received by the light receiving element has the features described in each claim with respect to the range of incident light. 7,
8, 9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24, 2
The optical information recording / reproducing apparatus according to any one of 5 or 26. 28. The incident angle range is within ± 10 degrees with respect to the incident angle near the optical axis.
7. The optical information recording / reproducing apparatus according to item 7. 29. The beam splitter has a structure in which a first transparent member and a second transparent member are bonded together, and a bonding surface of the first transparent member has a light splitting surface that constitutes the light splitting surface. A film is formed, and a bonding surface of the first transparent member on which the light separation film is formed and a bonding surface of the second transparent member are bonded via an adhesive layer, and the beam splitter is , The first transparent member is arranged so that the beam splitter reflects the light returning from the optical recording medium, and the light receiving unit receives the light reflected by the beam splitter and detects at least a reproduction signal. Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
11, 12, 13, 14, 15, 16, 17, 18, 1
9, 20, 21, 22, 23, 24, 25, 26, 27
29. The optical information recording / reproducing device according to 28. 30. The beam splitter or the polarization beam splitter is a flat plate-shaped transparent member on which a light separation film is formed.
2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16, 17, 18, 19, 20, 2
The optical information recording / reproducing apparatus according to any one of 1, 22, 23, 24, 25, 26, 27 or 28. 31. Of the light emitted from the light emitting element, the light separated by the beam splitter is received by a monitor light receiving element, and the beam splitter is caused by wavelength fluctuation of light incident on the monitor light receiving element. The reflective film is formed so that the change in light amount is within ± 10%.
9, 10, 11, 13, 17, 18, 19, 20, 2
1, 22, 23, 24, 25, 26, 27, 28, 29
31. An optical information recording / reproducing apparatus according to any one of 30. 32. A focus error signal and a tracking error signal are returned light from the optical recording medium through the beam splitter, and light directed toward the light emitting element is transmitted by a second light receiving means different from the light receiving means. It is detected, Claims 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11, 12, 13, 14, 15, 1
6, 17, 18, 19, 20, 21, 22, 23, 2
4. The optical information recording / reproducing apparatus according to any one of 4, 25, 26, 27, 28, 29, 30 or 31. 33. A second part for detecting the focus error signal and the tracking error signal by using a hologram element for the converged part of the returning light from the optical recording medium, which is directed toward the light emitting element via the beam splitter. 33. The optical information recording / reproducing apparatus according to claim 32, wherein the optical information recording / reproducing device collects the light. 34. The material of the first or second transparent member of the beam splitter is a material having a refractive index of 1.6 or more.
5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 2
3, 24, 25, 26, 27, 28, 29, 30, 3
The optical information recording / reproducing apparatus according to any one of 1, 32 and 33. 35. The optical information recording / reproducing apparatus reproduces information from an optical recording medium by detecting rotation of a plane of polarization of a light beam generated by reflection on the optical recording medium. Items 1, 2, 3, 4, 5, 6, 7, 8,
9, 10, 11, 12, 13, 14, 15, 16, 1
7, 18, 19, 20, 23, 24, 25, 26, 2
7. The optical information recording / reproducing apparatus according to any one of 7, 28, 29, 30, 31, 32, 33 or 34. 36. The light separation film or the reflection film is made of a birefringent substance, and the light separation film or the reflection film is formed of a birefringent substance. 11,
12, 13, 14, 15, 16, 17, 18, 19, 2
0, 23, 24, 25, 26, 27, 28, 29, 3
The optical information recording / reproducing apparatus according to any one of 0, 31, 32, 33, 34, and 35. 37. The light separation film or the reflection film is formed of a dielectric multilayer film, according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. 11,
12, 13, 14, 15, 16, 17, 18, 19, 2
0, 23, 24, 25, 26, 27, 28, 29, 3
0, 31, 32, 33, 34, 35 or 36, which is an optical information recording / reproducing apparatus. 38. The optical information recording / reproducing apparatus according to claim 36, wherein the light separation film or the reflection film is composed of a multilayer film, and the number of films is 5 or more. 39. The optical information recording / reproducing according to claim 36, 37 or 38, wherein the light separation film or the reflection film is composed of a multilayer film and includes at least one metal thin film. apparatus. 40. The optical information recording / reproducing apparatus according to claim 39, wherein the metal thin film is a layer farthest from the first transparent member. 41. The light separation film or the reflection film is composed of a multilayer film, and is made of at least four kinds of materials, 36, 37, 38, 39.
The optical information recording / reproducing apparatus according to item 40. 42. The optical information recording according to claim 36, 37, 38, 39, 40 or 41, wherein the light separation film or the reflection film is composed of a multilayer film and includes an extremely thin layer. Playback device. 43. The optical information recording / reproducing apparatus according to claim 42, wherein the extremely thin layer has an optical film thickness of 1/10 or less of a wavelength. 44. The light separation film or the reflection film is formed of a multi-layer film and includes at least one layer containing Hf or an oxide of Hf as a main component. 38, 39, 40, 41, 42 or 43. The optical information recording / reproducing apparatus. 45. The light separation film or the reflection film is formed of a multi-layer film and includes at least one layer containing Zr or an oxide of Zr as a main component. 38, 39, 40, 41, 42,
43. The optical information recording / reproducing apparatus according to 43 or 44. 46. The optical according to claim 44 or 45, wherein the layer containing the material according to claim 44 or 45 as a main component is a layer farthest from the first transparent member. Information recording / reproducing apparatus. 47. The first transparent member is at least Si.
And Pb are included.
7, 38, 39, 40, 41, 42, 43, 44, 45
Alternatively, the optical information recording / reproducing apparatus according to the item 46. 48. The light separation film or the reflection film is formed of a multilayer film, and the layer in contact with the first transparent member contains Pb.
7, 38, 39, 40, 41, 42, 43, 44, 4
The optical information recording / reproducing apparatus according to 5, 46 or 47. 49. The adhesive layer does not change physical and optical properties in an environment of 100 ° C. or higher. 29, 31, 32, 33, 34, 3
5, 36, 37, 38, 39, 40, 41, 42, 4
3, 44, 45, 46, 47 or 48, an optical information recording / reproducing apparatus. 50. Claims 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 13, 17, 18, 19, 21,
22, 23, 24, 25, 26, 27, 28, 29, 3
0, 31, 32, 33, 34, 35, 36, 37, 3
8, 39, 40, 41, 42, 43, 44, 45, 4
A beam splitter having the features described in 6, 47, 48, 49. 51. Claims 12, 13, 17, 18, 2
A polarizing beamsplitter having the features described in 5, 26, 27, 28, 30, 35, 36, 37 or 38. 52. Claims 14, 15, 16, 17, 1
8, 19, 20, 23, 24, 25, 26, 27, 2
8, 35, 36, 37, 38, 39, 40, 41, 4
A rising mirror having the features described in 2, 43, 44, 45, 46, 47 or 48.