JP2001154096A - Optical element, optical pickup device and recording/ reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element, which is suitable for a close distance optical system and also capable of thoroughly correcting aberration, to provide an optical pickup device using the optical element, and to provide a recording/ reproducing device equipped with the optical pickup device. SOLUTION: This optical element 31 is provided with an incident surface 51a, on which external light is made incident, on exit surface 35a for emitting the light to the outside, and reflection surfaces 34 and 33 for condensing at least a part of the light made incident on the incident surface to the exit surface. By constituting the incident surface of a material which is different from of the optical element main body 50, the optical surface capable of correcting aberrations is enlarged. The light, oozing through the exit surface 35a due to the close distance effect, is used for the optical pickup. The optical pickup device includes the optical element 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element having a reflecting surface and suitable for a near-field optical system, an optical pickup optical system using the optical element, an optical pickup device using the optical element, and an optical device using the optical element. The present invention relates to a recording / reproducing device including a pickup device.

[0002]

2. Description of the Related Art In recent years, in order to increase the storage capacity in high-density optical recording, attempts have been made to reduce the spot size of laser light condensed for reading and writing on an optical disk and have been put to practical use. The most common way to do this is to shorten the wavelength of the light source. For this reason, an objective lens that utilizes a near field is known as one that improves the recording density by shortening the wavelength of the focused spot light and simultaneously increasing the NA. For example, FIG. 7 shows an objective lens called SIL (Solid Immersion Lens) published in Optics Design and Fabrication '98. As shown in FIG. 7, in this objective lens, the first surface 91 is a concave refraction surface (incident surface), and gently diverges when a light beam from infinity is transmitted, but is reflected by the plane of the second surface 92. It is folded. And the third surface 93
The light is suddenly condensed by the reflecting surface, and focuses on the fourth surface 94, which is the exit surface, near the boundary surface with air. Most of the focal light is totally reflected because the optical medium constituting the objective lens has a higher refractive index than the air after emission.
At a distance of a fraction of the wavelength from the fourth surface 94, the light becomes an evanescent wave propagating on the fourth surface, and the light flux in the medium seeps into the air. At this time, the fourth surface 94 of the optical disk D is so captured as to capture this miserable light.
On the other hand, if it is arranged close to a near field of 100 nm or less, a converging spot for reading or writing can be formed on the optical disk at a wavelength in the medium.

In the above-mentioned objective lens, the light beam condensed at the large condensing angle θ on the third surface 93 has a large NA with the refractive index n of the medium, so that a very small spot size can be realized. The density can be dramatically increased.
For example, the wavelength λ of the light source is 650 nm, the refractive index n of the medium of the objective lens is 1.8, and the converging angle θ is 60 °.
Then the NA is 1.56 and the spot size is D
1 / 2.6 times that of VD applications. Therefore, the recording density is remarkably improved to 6.8 times, and is an objective lens suitable for an optical pickup optical system of an optical disk.

However, SIL such as the above-mentioned objective lens
The lens turns a catadioptric optical system often used in astronomical telescopes with a plane mirror and directs the outgoing light beam in the same direction as the incident light beam direction.The optical surface that contributes to reduce aberration is Incident surface (refractive surface) 91
And only two catadioptric reflecting surfaces 93. Although such an optical system is originally an optical system that is strong against decentering such as tilt, it can basically correct only spherical aberration and coma of an off-axis light beam. For this reason, it is difficult to realize sufficient aberration correction.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical element suitable for a near-field optical system and capable of sufficiently correcting aberrations, an optical pickup device using the optical element, and an optical pickup device using the optical element. To provide a recording / reproducing apparatus provided with the same.

[0006]

In order to achieve the above object, an optical element according to the present invention has an incident surface on which light from the outside enters,
An emission surface for emitting light to the outside, and a reflection surface for condensing light incident from the incidence surface on the emission surface, wherein the incidence surface is made of a material different from the optical element body. .

According to this optical element, the boundary surface between the entrance surface of a material different from that of the optical element main body and the boundary surface of the optical element main body is an optical surface, so that one optical surface that can contribute to aberration correction increases.
For this reason, sufficient aberration correction becomes possible, and an optical element having higher optical performance can be realized. Further, since the reflection surface is formed, an optical element suitable for a near-field optical system using the reflection surface can be provided.

Further, another optical element of the present invention has an incident surface on which light from the outside enters, a reflecting surface for reflecting the incident light, and an exit surface for emitting the light to the outside. The reflecting surface has at least a first reflecting surface and a second reflecting surface, the first reflecting surface reflecting incident light,
Is characterized in that the light reflected by the first reflection surface is focused on the emission surface, and the incidence surface is made of a material different from that of the optical element body.

According to this optical element, the boundary between the incident surface of a material different from the optical element main body and the optical element main body becomes the optical surface, so that one additional optical surface can contribute to aberration correction.
For this reason, sufficient aberration correction becomes possible, and an optical element having higher optical performance can be realized. Further, since the first and second reflecting surfaces are formed, an optical element suitable for a near-field optical system using these reflecting surfaces can be provided.

Still another optical element according to the present invention has a near-field effect on an exit surface where light from the outside enters from an incident surface and emits light to the outside. It is characterized by comprising different materials.

According to this optical element, the boundary between the entrance surface of a material different from that of the optical element main body and the optical element main body becomes the optical surface, so that one additional optical surface can contribute to aberration correction.
Therefore, it is possible to sufficiently correct aberrations in an optical element having a near-field effect, and an optical element having higher optical performance and having a near-field effect can be realized.

The refractive index of the material forming the incident surface may be different from the refractive index of the material of the optical element body.

[0013] The incident surface may be formed in a resin layer made of a resin material.

Further, the optical element body can be made of a glass material.

Further, the optical element body and the portion including the incident surface can be made of a resin material.

Further, the reflection surface can be a back mirror or a front mirror. Here, the surface mirror refers to a reflecting mirror having a configuration in which light rays enter the reflecting surface from outside the medium constituting the reflecting surface, are reflected at a reflection angle equal to the incident angle, and are reflected outside the medium. Further, the back mirror refers to a reflecting mirror in which a light beam enters from the medium constituting the reflection surface, reflects the light beam at a reflection angle equal to the incident angle, and returns the light beam to the medium.

Further, still another optical element of the present invention comprises an incident surface on which light from the outside enters, a reflecting surface of a back mirror for reflecting the incident light, and an exit surface for emitting light to the outside. Wherein the reflection surface includes at least a first reflection surface and a second reflection surface, wherein the first reflection surface reflects incident light, and wherein the second reflection surface is the first reflection surface. The light reflected by the optical element is condensed on the emission surface, and the second reflection surface is made of a material different from that of the optical element body.

According to this optical element, since the boundary surface between the second reflecting surface made of a material different from that of the optical element body and the optical element body becomes the optical surface, the number of optical surfaces that can contribute to aberration correction increases by one. For this reason, sufficient aberration correction becomes possible, and an optical element having higher optical performance can be realized. Also, the first
And the second reflecting surface are formed, so that an optical element suitable for a near-field optical system using these reflecting surfaces can be provided. Note that the different materials are materials whose refractive indexes are different from each other at least.

In this case, it is preferable that the entrance surface is made of a material different from that of the optical element body, because the number of optical surfaces that can contribute to aberration correction further increases.

Further, by forming the region including the emission surface or the region including the vicinity of the emission surface from a material having a high refractive index, the light condensed in this region oozes from the emission surface and the near-field optical system Thus, an appropriate optical element can be obtained.

An optical pickup device according to the present invention is characterized in that the above-described optical element is used for condensing light for an optical pickup.

Further, an optical pickup device of the present invention comprises a light source, the above-described optical element for condensing light from the light source on an information recording medium, and a light receiving element for receiving light from the information recording medium. The closest distance between the optical element and the information recording medium is λ / 2 (λ: wavelength of the light source) or less.

According to this optical pickup device, sufficient aberration correction can be performed, and light is focused on the information recording medium by an optical element having higher optical performance, so that reproduction or recording with less error can be performed.

Further, the closest distance is more preferably λ / 4 or less in order to use a large amount of near-field light.

A recording / reproducing apparatus according to the present invention includes the above-described optical pickup device, and is capable of recording and / or reproducing at least one of audio and video.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of an optical element showing an embodiment of the present invention. The optical element shown in FIG. 1 has an incident layer made of a material different from that of the optical element body, and has a reflecting surface formed as a back mirror.

The optical element 31 shown in FIG. 1 has a concave surface 32 formed around the optical axis p, a spherical concave surface 51a to which light from the outside enters, and a convex surface 51 having a shape complementary to the concave surface 32.
b, a first reflecting surface 34 formed on the bottom 35 so that light from the concave surface 51a enters and reflects the light, and a first reflecting surface formed around the concave surface 32. A second reflection surface 33 that reflects light from the bottom 34 toward the vicinity of the center of the bottom 35;
And a light exit surface 35a of the light from the reflection surface 33.
Further, a flange portion 37 is formed so as to protrude from the outer periphery of the optical element 31 in a direction substantially perpendicular to the optical axis p, and this flange portion 37 is used when attaching the optical element to an optical pickup device.

The main body 50 of the optical element 31 is formed of a resin material so as to be translucent by integral molding. First and second
The reflection surfaces 34 and 33 are formed as back mirrors, and the second reflection surface 33 has a curvature such that the light from the first reflection surface 34 is reflected and collected near the center of the bottom 35. The first reflection surface 33 is formed in a donut shape in a region near the center of the bottom surface 35 except for the emission surface 35a. The incident layer 51 is formed of another resin material having a different refractive index from that of the optical element main body 50 so as to be translucent by molding. The optical element body 50
1 means the entire optical element 31 in FIG.

As the resin material constituting the optical element body 50, a thermoplastic resin, a thermosetting resin or a photocurable resin can be used, and optical glass may be used. Resin is less affected by heat compared to thermoplastic resin, and can be more durable against heat.In addition, optically anisotropic, less birefringent, and optically accurate optical element it can. Further, since molding can be performed at a lower temperature, it is advantageous in terms of manufacturing cost.

Preferred examples of the thermosetting resin include UV 1000, 2000, 300 manufactured by Mitsubishi Chemical Corporation.
0, MR-6, -7 manufactured by Mitsui Chemicals, and Desolite manufactured by Nippon Synthetic Rubber. Further, as preferable specific examples of the photocurable resin, UV1000, 2000, manufactured by Mitsubishi Chemical Corporation,
3000 and Nippon Kayaku Kayarad, Mitsui Chemicals MR
-6 and -7. In the case of photocurable resin, a part of the molding die is made of a material such as glass that transmits ultraviolet light, and after filling the molding resin with a liquid resin at room temperature, it is cured by irradiating it with ultraviolet light. The element can be shaped.

First reflection surface 34 and second reflection surface 33
Can be formed on the optical element 50 by a vapor deposition method using, for example, a silver material, and at least 50% or more of the light incident on each of the reflection surfaces 34 and 33 is reflected. More preferably, the reflectance is 90% or more.

The incident layer 51 can be formed by molding with a thermosetting resin or a photocuring resin. When the optical element body 50 is formed of glass, it is molded with a thermoplastic resin by an insert molding method of injection molding. It is also possible.
The concave surface 51a of the incident layer 51 has a spherical shape, but may have an aspherical shape, and can be similarly formed by molding.

When both the incident layer 51 and the optical element main body 50 are made of a resin material, the incident layer 51 is formed of, for example, a silicon resin material (refractive index: 1.43), and the optical element main body 50 is made of an episulfide resin. Material (refractive index: 1.
71).

According to the optical element 31 shown in FIG. 1, substantially parallel light enters from the concave surface 51a of the incident layer 51 from the upper side of the figure, passes through the concave surface 32 functioning as an optical surface, and diffuses around the optical axis p. The light that travels through the optical element 31 is reflected by the first reflecting surface 34, and is reflected by the second reflecting surface 3.
3, the light is further reflected toward the vicinity of the center of the bottom 35,
And exits from the exit surface 35a to the outside. At this time, λ / 2 from the exit surface 35a due to the near-field effect.
Light exudes within the range of (λ is the wavelength of light). The exuded light can be used for an optical pickup in an optical information recording medium, for example, as shown in FIG. 4 described later.

The optical element shown in FIG. 1 is provided with an incident layer 51, whose concave surface 51a and concave surface 32 both function as optical surfaces and can correct aberrations on both surfaces 51a and 32. As a result, the number of optical surfaces that can contribute to aberration correction increases by one, so that the degree of freedom in optical design increases and higher optical performance can be secured. Increasing the number of optical surfaces with a simple optical system such as an optical element having a near-field effect is very effective in reducing aberrations of the optical element, and achieving further improvement in optical performance. Can be.

Next, two modified examples of the optical element shown in FIG. 1 will be described with reference to FIGS. 2 and 3. The optical element 41 of FIG.
The second reflection surface 33 is made translucent, and the reflection layer 52 made of a material different from that of the optical element body 50 is formed on the surface 3 of FIG.
3 is provided so as to cover the third reflective surface 52, and the outer surface of the reflective layer 52 is a second reflective surface 53. The second reflection surface 53 is formed with a curvature such that light from the first reflection surface 34 is condensed near the center of the bottom surface 35. The reflection layer 52 can be formed integrally with the incident layer 51 by molding.

In the vicinity of the center of the bottom 35 of the optical element body 50, a high refractive area 36 (refractive index n) having a higher refractive index than the optical element body 50 is formed. High refraction area 36
For example, is embedded in the optical element body 50 and is formed in a substantially hemispherical shape by sputtering, vapor deposition, ion exchange, doping, or the like.

According to the optical element 41 shown in FIG. 2, light is transmitted through the optical surface 33 which is the original reflecting surface,
Since the light beam is transmitted twice before and after the reflection, it can be used as an aberration correction surface, and the second reflection surface 53 can also perform aberration correction. Therefore, as compared with the case of FIG. Is increased by one, the degree of freedom in optical design is further increased, and higher optical performance can be secured.

Since the high refraction region 36 is provided, the second
The light reflected from the reflection surface 53 and condensed and incident on the high refraction region 36 exits from the emission surface 36a to the outside. At this time, λ / 2 (λ is the wavelength of light ), Near-field light having a wavelength of λ / n exudes within the range of the distance of). This exuded light can be used, for example, for an optical pickup in an optical information recording medium,
Light with a smaller spot size can be obtained, and higher density recording on an optical information recording medium is possible.

Next, another modification of the optical element 3 of FIG.
Reference numeral 9 denotes a configuration in which the first reflecting surface 34 of the optical element 41 in FIG. 2 is formed as a first reflecting surface 38 having a curvature. According to the optical element 39, the number of optical surfaces on which aberrations can be optically corrected is one more than in the case of FIG. 3, so that more sufficient aberration correction can be performed, and good optical performance can be easily ensured.

Next, an optical pickup optical system and an optical pickup device including the optical element shown in FIG. 2 will be described with reference to FIG.

An optical pickup device 20 shown in FIG. 4 comprises an optical pickup optical system 21, a light source 22 composed of a laser diode, and a light receiving sensor 23 composed of a photodiode.
, And is configured to read information from the optical disc 10 of the optical information recording medium by light from the light source 22. The optical pickup device 20 is provided with an auto servo mechanism (not shown) so as to be able to automatically move in the horizontal direction of FIG. 4 with respect to the optical disk 10, and to automatically move in the vertical direction of FIG. An auto tracking servo mechanism (not shown) is provided.

The optical pickup optical system 21 includes a diffraction grating 24 for diffracting a laser beam from a light source 22 and a diffraction grating 24.
A beam splitter 25 that reflects light from the optical disk 6 toward the optical disk 10 and transmits light from the optical disk 6 toward the light receiving sensor 23, a collimator lens 26 that converts the light reflected by the beam splitter 25 into parallel light, and a collimator lens The parallel light from the optical disk 26 enters the optical disk 10
And an optical element 41 for focusing light. Optical disk 1
0 is arranged very close to the exit surface 36a of the optical element 41, and the distance between the optical disk 10 and the exit surface 36a of the optical element 41 is such that the intensity of the near-field light is exponential due to the distance from the exit surface 35a. When the wavelength of the light source 22 is λ, λ / 2 is preferable, and λ / 4 is more preferable.

According to the optical pickup device 20 shown in FIG.
The laser light from the light source 22 is diffracted by the diffraction grating 24, reflected by the beam splitter 25, converted into parallel light by the collimator lens 26, and then enters the optical element 41 from the incident layer 51. The incident light is reflected by the first and second reflecting surfaces 34 and 52a as described with reference to FIGS.
, Is incident on the high refraction region 36, and exits from the exit surface 36a. At this time, light having a wavelength of λ / n exudes within a range of λ / 2 from the emission surface 36a due to the near-field effect. The light due to the near-field effect is irradiated onto the rotating optical disk 10, the light is reflected from the optical disk 10, and the reflected light follows the reverse path to the above.
The information recorded on the optical disk 10 can be read by passing the beam splitter 25 and receiving the light by the light receiving sensor 23 and converting the intensity of the light into an electric signal.

As described above, since the optical element 41 can perform aberration correction more sufficiently than the conventional one, an optical pickup device with further reduced reading error can be realized in FIG. In addition, it is possible to write and record information on an optical information recording medium, and high-density recording can be performed by light having a small spot diameter obtained by the optical element 41.

Next, another optical element will be described with reference to FIG. In this optical element, an incident layer is provided, and a reflection surface is configured as a surface mirror.

As shown in FIG. 5, the optical element 1 has a concave surface 2
a and a concave lens portion 2 having a concave surface 2b;
A hollow portion 8 formed therein so as to be surrounded by the optical element body 3 and the flat plate portion 5, a flat plate portion 5, and a first reflecting surface 6 formed flat on the outer peripheral side of the flat plate portion 5. A second reflection surface 4 formed on the inner surface of the cavity 8 and reflecting the light from the first reflection surface 6 so as to converge the light toward the center of the flat plate portion 5;
A high-refractive-index region formed near the center of the flat plate portion;

Further, the optical element 1 has an incident layer 12 having a spherical concave surface 12a to which light from the outside is incident and a convex surface 12b having a shape complementary to the concave surface 2b of the concave lens portion 2.
Is provided. The incident layer 12 is provided so as to cover the concave lens portion 2, and is formed of a material different from the optical element body 3. Note that the optical element body 3 refers to the entire portion including the concave lens portion 2 and the second reflection surface 4 in FIG.

The flat portion 5 is made of a light-transmitting material such as a glass plate, and has a first reflecting surface 6 formed on the outer periphery of the central portion 9. The second reflecting surface 4 is formed with a curvature such that light is focused toward the center of the flat plate portion 5. The first reflection surface 6 and the second reflection surface 4 can be formed, for example, by a vapor deposition method using a silver material, and at least 50% or more of the light incident on each of the reflection surfaces 6, 4 is reflected. I have. The flat plate portion 5 can be fixed to the optical element main body 3 at its outer periphery by bonding or the like.

The high-refractive-index region 7 having a refractive index n formed near the center 9 of the flat plate portion 5 is formed to have a higher refractive index than the translucent material of the flat plate portion 5. And is formed in a substantially hemispherical shape by ion exchange, doping, or the like.

Although the concave surface 12a of the incident layer 12 has a spherical shape, it may have an aspherical shape and can be formed by molding in the same manner. As described above, the optical surface shape of the incident layer 12 does not matter, and the power at the incident surface may be positive or negative. The optical element body 3 and the incident layer 12 can both be made of a resin material, but can be made of materials having different refractive indexes as described above. Further, the optical element body 3 may be made of glass.

As described above, the optical element shown in FIG.
2, the concave surface portion 12a and the concave surface 2a both function as optical surfaces and can correct aberrations on both surfaces 12a and 2a. Is increased by one, and higher optical performance can be secured. Increasing the number of optical surfaces with a simple optical system such as an optical element having a near-field effect is very effective in reducing aberrations of the optical element, and achieving further improvement in optical performance. Can be.

In the optical element having the above-described configuration of the surface mirror, since the incident light is condensed by the surface mirror in the air, the NA does not increase to 1 or more.
Since the high refraction region 7 is provided, the NA can be increased by the refractive index of the material constituting the high refraction region 7. For example,
The refractive index of the high refraction region 7 is set to 2.4 (SiO ₃ ) or 2.8.
(TiO ₂ ), the NA was 0.86 (θ = 60 °) when there was no high-refractive area 7.
2.1 and 2.4. Therefore, light with a small spot diameter can be obtained, and when used in an optical pickup device, high-density recording of 4.4 times or 5.8 times becomes possible.
You.

Further, in the optical element having the configuration of the surface mirror as shown in FIG. 5, since the incident light is condensed by the surface mirror in the air, the NA does not increase to 1 or more.
Since the high refraction region 7 is provided, the NA can be increased by the refractive index of the material constituting the high refraction region 7. For example,
The refractive index of the high refraction region 7 is set to 2.4 (SiO ₃ ) or 2.8.
(TiO ₂ ), the NA was 0.86 (θ = 60 °) when there was no high-refractive area 7.
2.1 and 2.4. Therefore, light with a small spot diameter can be obtained, and when used in an optical pickup device, high-density recording of 4.4 times or 5.8 times becomes possible.

FIG. 6 shows an optical pickup device in which the optical element 1 of FIG. 5 is arranged in place of the optical element of FIG. Also in the optical pickup device of FIG. 6, the same effect as that of FIG. 4 can be obtained by the optical element having the near-field effect.

In this specification, the term “reflecting surface” refers to a surface that reflects 50% or more (preferably 90% or more) of light incident on the reflecting surface.

[0057]

According to the present invention, an optical element suitable for a near-field optical system and capable of sufficiently correcting aberrations, an optical pickup device using the optical element, and a recording / reproducing apparatus including the optical pickup device Can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical element according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a modification of the optical element of FIG.

FIG. 3 is a sectional view showing another modified example of the optical element of FIG. 1;

FIG. 4 is a diagram schematically illustrating an optical pickup optical system (including the optical element of FIG. 2) and an optical pickup device including the optical system according to the embodiment of the present invention.

FIG. 5 is a sectional view of another optical element according to the embodiment of the present invention.

6 is a view similar to FIG. 4, illustrating an optical pickup optical system including the optical element of FIG. 5 and an optical pickup device including the optical system;

FIG. 7 is a cross-sectional view of a conventional optical element.

[Explanation of symbols]

1, 31, 39, 41 Optical element 2 Lens part 2a, 2b, 32 Concave surface 3,50 Optical element body 6,34,38 First reflective surface 4,53 Second reflective surface 33 Second reflective surface, optical Surface 37 Flange portion 7, 36 High refraction region 7a, 35a, 36a Emission surface 12, 51 Incident layer (resin layer) 12a, 51a Concave surface 52 Reflection layer 20 Optical pickup device 21 Optical pickup optical system 22 Light source 23 Light receiving sensor 26 Collimator lens

Claims (17)

[Claims] An incident surface on which light from the outside is incident, an exit surface for emitting light to the outside, and a reflecting surface for condensing light incident from the incident surface on the exit surface; An optical element characterized in that the incident surface is made of a material different from that of the optical element body. 2. An apparatus according to claim 1, further comprising an incident surface on which light from the outside is incident, a reflecting surface for reflecting the incident light, and an emitting surface for emitting light to the outside, wherein the reflecting surface is at least a first reflection surface. And a second reflecting surface, wherein the first reflecting surface reflects the incident light, and the second reflecting surface condenses the light reflected by the first reflecting surface on the emission surface. An optical element, wherein the incident surface is made of a material different from that of the optical element body. 3. A light-emitting device according to claim 1, wherein a light from outside enters from an incident surface and has an near-field effect on an exit surface for emitting light to the outside, and the incident surface is made of a material different from that of the optical element body. Optical element. 4. The optical element according to claim 1, wherein a refractive index of a material forming the incident surface is different from a refractive index of a material of the optical element body. 5. The optical element according to claim 1, wherein said incident surface is formed in a resin layer made of a resin material. 6. The optical element according to claim 1, wherein said optical element body is made of a glass material. 7. The optical element according to claim 1, wherein said optical element body and said incident surface are made of a resin material. 8. The mirror according to claim 1, wherein the reflecting surface is a back mirror.
The optical element according to any one of the above. 9. The reflection surface is a surface mirror.
The optical element according to any one of the above. 10. An incident surface on which light from the outside is incident, a reflecting surface of a back mirror for reflecting the incident light, and an exit surface for emitting light to the outside, wherein the reflecting surface is at least a first surface. A first reflection surface and a second reflection surface, wherein the first reflection surface reflects incident light, and the second reflection surface transmits light reflected by the first reflection surface to the emission surface. An optical element, wherein the second reflection surface is made of a material different from that of the optical element body. 11. The optical element according to claim 10, wherein the incident surface is made of a material different from that of the optical element body. 12. The optical element according to claim 1, wherein the region including the emission surface is made of a material having a higher refractive index than other portions. 13. The optical element according to claim 1, wherein a region including the vicinity of the emission surface has a higher refractive index than other portions. 14. An optical pickup device using the optical element according to claim 1 for condensing light for an optical pickup. 15. A light source, and condensing light from the light source on an information recording medium.
13. An optical element according to claim 13, further comprising: a light receiving element configured to receive light from the information recording medium, wherein a closest distance between the optical element and the information recording medium is λ /
2 (λ: wavelength of the light source) or less. 16. The optical pickup device according to claim 15, wherein the closest distance is λ / 4 or less. 17. A recording / reproducing apparatus comprising the optical pickup device according to claim 15 and capable of recording and / or reproducing at least one of audio and images.