JPH10241185A - Optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical pickup in which excellent optical characteristics can be sustained even if the size is reduced by an arrangement wherein at least two optical blocks constituting an optical member have a plurality of inclining faces and at least one inclining face is provided with an optical element. SOLUTION: Reflective films 43, 44 are formed on the first inclining face 41a of a first optical member 41. The reflective film 43 reflects a light emitted from a light source 2 in a specified direction and the reflective film 44 reflects a light emitted from a light source 9 in a specified direction. Polarization separation films 45, 46 are formed on the second inclining face 41b. A light reflected on the reflective film 44 impinges on the polarization separation film 46 and a light reflected on the reflective film 43 impinges on the polarization separation film 45. Since the light can be introduced to a recording medium without substantially reducing the quantity of light passing through these polarization separation films 45, 46, utilization efficiency of light can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device for recording and reproducing information on and from an optical disk.
Conventional optical disks such as CDs and CD-ROMs and digital video disks (DVD, DVD-ROM, DVD-RA
The present invention relates to an optical pickup capable of recording and reproducing on and from an optical disc having different specifications such as a thickness of a disc substrate and a recording density, such as a high-density optical disc such as M).

[0002]

2. Description of the Related Art Compact discs (CDs, CD-ROMs) have been widely used as conventional optical discs as media for music software and computer software. High-density optical disks (DVD, DVD-ROM) have been proposed and are being put to practical use. In a high-density optical disk, the numerical aperture of the condensing means of the optical pickup is increased from 0.45 of the conventional optical disk to 0.60, and the wavelength of the semiconductor laser is increased from 780 nm of the conventional optical disk to 65.
By shortening the wavelength to 0 nm or 635 nm,
The diameter of the spot formed on the recording surface of the optical disk is further reduced, and the recording density is increased to about 4.2 times that of the conventional optical disk. On the other hand, the wavefront aberration caused by the tilt of the disk is proportional to the cube of the numerical aperture and the thickness of the disk substrate. Therefore, in a high-density optical disk, the thickness of the disk substrate is reduced in order to suppress the increase of the wavefront aberration due to the tilt of the disk. It is set to 0.6 mm, which is half of the conventional optical disk of 1.2 mm.

[0003] Against this background, optical pickup devices for high-density optical discs have been developed to use not only high-density optical discs but also conventional optical discs in order to make effective use of software assets published to date. Is required to be able to be reproduced. However, if an optical system designed for a high-density optical disc is used as it is on a conventional optical disc, a large spherical aberration occurs due to the difference in the thickness of the disc substrate, and the image spot is blurred and information cannot be reproduced. Occurs.

[0004] In addition, a CD-ROM is used as a third recording medium.
There is a one-time rewritable write-once optical disc called R. Since the reflection film of this CD-R has a very high wavelength dependency, it is 780 nm specified in the standard.
Only light sources having near oscillation wavelengths can be used.

A conventional technique for solving this problem will be described in detail below. FIG. 13 is a diagram showing an optical system of a conventional optical pickup. In FIG. 13, reference numerals 200 and 300 denote light sources. The light source 200 is a semiconductor laser having a wavelength of 635 to 650 nm used for reproducing a high-density optical disk. The wavelength used for reproducing a low-density optical disk is 78.
It is a semiconductor laser of 0 nm. Reference numeral 201 denotes a prism, and the prism 201 is provided with a half mirror 201a. Reference numeral 202 denotes a collimator lens.
Numeral 02 has a function of converting diffused light into parallel light. 2
Reference numeral 03 denotes an objective lens holding unit. The objective lens holding unit 203 holds a lens 204 for a low-density optical disk and a lens 205 for a high-density optical disk. Objective lens holder 2
Reference numeral 03 denotes a configuration that allows the lens to be switched according to the type of the optical disk. 206 is a high-density optical disk, and 207 is a low-density optical disk.

The operation of the optical pickup device shown in FIG. 13 will be described below. First, the operation for a low-density optical disk will be described. Referring to FIG.
The light emitted from 0 enters the prism 201 with a predetermined diffusion angle, and only the light beam 208 reflected by the half mirror 201a enters the collimator lens 202. The light flux 209 converted from the diffused light into the parallel light by the collimator lens 202 enters the objective lens. Here, as the objective lens, the objective lens holding unit 203 is switched in advance so that the objective lens 204 for a low-density optical disk is arranged. Lens 20 for low density optical disc
The light beam 209 incident on the optical disk 4 is condensed and converged on the low-density optical disk 207. Then, the light reflected by the low-density optical disk 207 is guided to a light receiving element (not shown) via a predetermined path.

Next, the operation for a high-density optical disk will be described. 8, light emitted from a light source 200 enters a prism 201 with a predetermined diffusion angle, and only a light beam 210 transmitted through a half mirror 201a enters a collimator lens 202. The light flux 21 converted from the diffused light into the parallel light by the collimator lens 202
1 enters the objective lens. Here, as the objective lens, the objective lens holding unit 203 is switched in advance so that the high-density optical disk lens 205 is arranged. Light flux 21 incident on objective lens 205 for low density optical disc
1 is collected and converged on the high-density optical disk 206.
The light reflected by the high-density optical disk 206 is guided to a light receiving element (not shown) via a predetermined path.

At this time, which light source is used,
Which objective lens is used is switched by determining whether the disk set by the user has a high density or a low density.

[0009]

However, in the above-described conventional configuration, the light emitted from the light source 200 and the light source 300 is directly transmitted through the prism 201 to the collimator lens 2.
02 and the objective lens. For this reason, the optical path from each light source to the recording medium becomes very long, which makes it very difficult to miniaturize the optical pickup.

[0010] The present invention solves the above-mentioned conventional problems, and reduces the substantial optical path length from a light source to a recording medium.
It is intended to provide a small and thin optical pickup.

[0011]

In order to solve the above-mentioned problems, the inclination direction of a slope formed on an optical member that reflects light incident from a light source a plurality of times and guides the light to a predetermined optical path is determined for each optical member. So that the direction is constant.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The invention according to claim 1 is an optical member having a light source, at least two optical blocks for guiding light emitted from the light source to a predetermined optical path via an optical element, and the optical member. An optical pickup comprising: a light receiving unit configured to receive light guided through a member and reflected by a recording medium, wherein the light source, the optical member, and the light receiving unit are included in one package. Since at least two of the optical blocks have a plurality of slopes, and at least one of the slopes is provided with an optical element, a predetermined optical path length can be obtained while reducing the size of the optical member. it can.

According to the second aspect of the present invention, since the plurality of inclined surfaces of the optical block have the same inclination direction, the optical member can be easily assembled.

According to the third aspect of the present invention, since the inclination direction of the inclined surface of the optical block is different for each optical block, an optical path can be formed three-dimensionally in the optical member.

According to the fourth aspect of the present invention, the angle between the inclined surface and the optical axis of the incident light is in the range of 30 ° to 60 °, so that the size of the optical member can be further reduced.

According to the fifth aspect of the present invention, since the angle between the inclined surface and the optical axis of the incident light is approximately 45 °, the miniaturization of the optical member can be performed most efficiently.

According to a sixth aspect of the present invention, there is provided the first light source,
A second light source, and a plurality of slopes, and a light emitted from the first light source and a light emitted from the second light source are passed through an optical element formed on the plurality of slopes in a predetermined manner. An optical member having at least two optical blocks leading to an optical path;
Light receiving means for receiving light guided from the optical member and reflected by a recording medium, wherein the first light source, the second light source, the optical member, and the light receiving means are one An optical pickup in a package, wherein the inclination direction of the slope of the optical block constituting the optical member is a fixed direction for each optical block, so that the optical characteristics of light from a plurality of light sources are Optimization in the optical member can be easily performed.

According to a seventh aspect of the present invention, a first light source includes:
A first optical member having a second light source, a plurality of slopes, and guiding light emitted from the first light source to a predetermined optical path via an optical element formed on the slope, and a plurality of slopes; A second optical member that guides light emitted from the second light source to a predetermined optical path via an optical element formed on the slope, and a recording medium that is guided from the first optical member and A first light receiving means for receiving the light reflected by the first optical member, and a second light receiving means for receiving the light guided from the second optical member and reflected by the recording medium; An optical pickup in which a light source, the second light source, the first optical member, the second optical member, the first light receiving means, and the second light receiving means are formed in one package And the inclination of a plurality of slopes of the first optical member or the second optical member. Direction by a constant direction for each of the optical member, it becomes possible to be easily is to optimize each with an optical member in which the optical characteristics of the light provided for each light source from a plurality of light sources.

According to an eighth aspect of the present invention, the first optical member includes at least two optical blocks each having a plurality of inclined surfaces.
And the second optical member has at least two optical blocks having a plurality of slopes,
The inclination direction of the slope is a fixed direction for each optical block, so that the optical characteristics of light from a plurality of light sources can be easily optimized in the optical members provided for each light source. In addition, the size of the optical member can be reduced.

(Embodiment 1) First, Embodiment 1 of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration and an optical path of an optical pickup device according to Embodiment 1 of the present invention. FIG. 1
Among them, a dotted line shows an optical path when reproducing a conventional optical disk, and a solid line shows an optical path when reproducing a high-density optical disk. In FIG. 1, reference numeral 1 denotes a first package, on which a light source 2 for emitting light for a high-density optical disk, a light receiving element 3 for receiving light reflected by the high-density optical disk, and the like are mounted. And a side wall 1b provided so as to include the substrate portion 1a to be provided. These substrate portion 1a and side wall portion 1
b and the like may be formed integrally or separately. When formed integrally, the assembly process can be simplified, and productivity can be improved. First Package 1
It is preferable to use a material such as a metal or a ceramic as a material for forming, because heat generated in the light source 2 can be satisfactorily emitted.

Among the metallic materials, metallic materials such as Cu, Al and Fe having high thermal conductivity, FeNi alloy and FeN
It is preferable to use an alloy material such as an iCo alloy. This is because these materials are inexpensive, have high heat dissipation, and also have an effect as an electromagnetic shield that blocks noise such as electromagnetic waves from a high-frequency superimposing circuit or the like. Among them, in particular, Fe, FeNi alloy, and FeNiCo alloy have low thermal resistance and good heat dissipation, so that the heat generated by the light source 2 can be efficiently released to the outside. Since these materials are low in cost, it is possible to provide the optical pickup device at low cost.

The first package 1 has a substrate 1a.
By contacting the side wall portion 1b with a carriage (not shown) having a large heat capacity as necessary,
The heat generated in is released to the outside. Therefore, the larger the area of the substrate portion 1a in contact with the carriage, the better the heat radiation.

In this embodiment, the package 1
Is composed of the substrate part 1a and the side wall part 1b.
And a cap such as a lid.

Further, a terminal 1c for supplying power to the light source 2 and transmitting an electric signal from the light receiving element 3 to an arithmetic circuit (not shown) is provided on the substrate 1a. The terminal 1c may be a pin type or a print type. Here, the case where the terminal 1c is formed in a pin type will be particularly described. The terminal 1c is inserted into a plurality of holes (not shown) provided in the substrate 1a while not electrically contacting the substrate 1a made of a metal material. It is preferable to use an FeNiCo alloy, an FeNi alloy, an FeCr alloy or the like as a material of the terminal 1c. As means for cutting off the electrical contact between the substrate part 1a and the terminal 1c, the terminal 1
It is preferable to provide an insulating film or the like at a portion where c is in contact with the substrate portion 1a, and it is preferable that the portion is sealed so that outside air does not enter from this portion. As a material satisfying such requirements, it is preferable to use a material capable of simultaneously performing both insulation and sealing, such as a hermetic seal. Here, it is particularly preferable to use an alignment sealing type or compression sealing type hermetic seal. This is because these members can very easily perform both insulation and sealing, and are extremely inexpensive, so that the process of attaching the terminals 1c to the substrate 1a can be simplified, and the manufacturing cost of the optical pickup can be reduced. This is because it can be reduced. At the same time, high airtightness and insulation can be maintained over a wide temperature range, so that the reliability of the optical pickup can be increased and the terminal shape can be relatively freely deformed, so that the degree of freedom of design can be improved. Can also be increased.

It is preferable to use a monochromatic light source having good coherence, directivity and light condensing properties, since a beam spot having an appropriate shape can be formed relatively easily and noise and the like can be suppressed. preferable. It is preferable to use various types of laser light such as solid, gas, and semiconductor to satisfy such conditions. In particular, a semiconductor laser is very small in size, and can easily realize miniaturization of an optical pickup.

The oscillation wavelength of the light source 2 at this time is 80
It is preferable that the diameter be equal to or less than 0 nm because the beam spot when the light emitted from the light source converges on the recording medium can be easily made as large as the pitch of the track formed on the recording medium. Further, when the oscillation wavelength of the light source 2 is 6
If it is 50 nm or less, a beam spot small enough to be able to reproduce even a recording medium on which information is recorded at a very high density can be formed, so that a large-capacity storage means can be easily realized, In particular, it is preferable as the light source 2 used for recording and reproduction on a high-density optical disk.

When the light source 2 is constituted by a semiconductor laser,
Materials that can realize an oscillation wavelength of about 00 nm or less include AlGaInP, AlGaAs, ZnSe, and GaN.
Among these, AlGaAs is a preferable material because crystal growth is easy among compound materials, and therefore, semiconductor lasers are easy to manufacture. Therefore, high yield and high productivity can be realized. is there. Materials that can realize an oscillation wavelength of 650 nm or less include AlGaInP, ZnSe, and GaN. By using a semiconductor laser using these materials as the light source 2, the beam spot diameter formed on the recording medium can be made smaller, so that the recording density can be further improved. Playback becomes possible.

Among them, AlGaAsP is a preferable material because it has stable performance over a long period of time and can improve the reliability of the light source 2.

The output of the light source 2 is about 3 to 10 (mW) in the case of reproduction only, so that the energy consumption can be suppressed to a minimum while the light quantity required for reproduction is sufficiently secured. Further, the amount of heat emitted from the light source 2 can be suppressed, which is preferable. In the case of recording / reproducing, large energy is required to change the state of the recording layer during recording, so that an output of at least 25 (mW) or more is required. However, if the output exceeds 60 mW, it becomes difficult to release the heat emitted from the light source 2 to the outside.
In addition, there is a risk that the life of the light source will be significantly reduced, and in the worst case, the light source will be destroyed. For this reason, the electric circuit may malfunction or the light source 2
It is not preferable because the oscillation itself shifts the wavelength due to wavelength fluctuation, or noise is mixed in the signal, so that the reliability of the optical pickup is greatly reduced.

The first optical member 5 is joined to the light emitting portion 1d of the package 1. The first optical member 5 includes the light source 2
The light emitted from the device and reflected by the recording medium is
Has a function of guiding to a predetermined position. Here, a configuration will be described in which the first optical member 5 has a plurality of slopes and guides the return light using the optical elements formed on each slope.

The first optical member 5 has a first slope 5a and a second slope 5b formed therein.

The first slope 5a and the second slope 5b are formed to have the slopes in the same direction. First
With the above-described configuration of the inclined surface 5a and the second inclined surface 5b, it is possible to obtain a predetermined optical path length while shortening the length of the first optical member 5 in the height direction. The optical pickup can be downsized while maintaining the characteristics. In particular, when the optical head composed of the first optical member 5 and the like is mounted on a carriage (not shown), the center of gravity of the optical head exists at a position close to the mounting surface, so that high mounting accuracy can be realized. In addition, the displacement during bonding can be suppressed at a high rate.

Further, by making the inclination angles of the first slope 5a and the second slope 5b equal, a plurality of parallel flat plates in which a predetermined optical element is formed in advance are joined and cut out at a predetermined angle. Therefore, the first optical member 5 can be easily manufactured with high accuracy, and the productivity of the first optical member 5 is greatly improved. In addition, since the angle is determined in advance, the optical axis can be easily adjusted, and the time and process required for axis alignment can be reduced.

The angle of inclination of the first slope 5a and the second slope 5b with respect to the incident light is preferably in the range of 30 ° to 60 °, and more preferably about 45 °.

The first slope 5a and the second slope 5b are preferably provided at a predetermined distance from each other in view of the relationship with the optical elements formed on the slope. If a predetermined distance is not provided between the optical elements, light transmitted slightly without being reflected will leak into the optical path of the emitted light beam,
There is a high possibility that inconvenience such as becoming a stray light component will occur.

Assuming that this predetermined distance is L, when the inclination angle of the slope is smaller than 30 °, the difference L / I between the incident positions generated before the light is reflected by the first slope 5a and enters the second slope 5b. In the case of だ け (3) only, the thickness of the first optical member 5 becomes thicker, and if the angle is further increased, the difference in the incident position caused to take the same distance L, so that the volume of the first optical member 5 becomes the same. The size of the optical pickup becomes large, which makes it difficult to reduce the size of the optical pickup.

Further, when the inclination angle of the inclined surface is larger than 60 °, the volume of the first optical member 5 also becomes large as described above, which makes it difficult to miniaturize the optical pickup.

Here, particularly when the inclination angle is approximately 45 °, the difference in the incident position of the light reflected on the first inclined surface 5a and incident on the second inclined surface 5b can be almost eliminated. This is preferable because the size of the optical member 5 can be reduced most efficiently, and the size of the optical pickup can also be reduced efficiently.

Further, an optical path dividing means 6 composed of a half mirror, a polarization splitting film or the like is formed on the first slope 5a, and the incident light is guided to the light receiving element 3 on the second slope 5b. Reflecting means 7 is formed. In particular, when a high-density optical disk can be rewritten, it is necessary to irradiate the optical disk with very high energy.
It is necessary to guide the light emitted from the optical disk onto the optical disk as efficiently as possible. Taking this into consideration, using the optical path splitting means 6 as a polarization separating film and using it in combination with the 波長 wavelength plate 4 improves the light use efficiency, and enables recording or reproduction using a plurality of types of optical disks. It is preferable because it can be performed. Further, since the amount of light emitted from the light source 2 can be suppressed, the life of the light source 2 can be extended, and the reliability of the optical disk device can be improved, which is preferable.

The quarter-wave plate 4 has a function of converting the linearly polarized light into elliptically polarized light, and the elliptically polarized light reflected by the recording medium and having the opposite rotation direction is used as described above. Is converted into linearly polarized light orthogonal to the incident polarization direction.

It is preferable that an optical element corresponding to the purpose (for example, formation of a focus error signal using astigmatism) is arranged at the position of the reflection means 7. For example, when a focus error signal is formed by the knife edge method, an optical element capable of forming a knife edge is formed at the position of the reflecting means 7, and when a focus error signal is obtained by the astigmatism method. At the position of the reflection means 7, an optical element capable of forming astigmatism is formed. Considering that these optical elements are formed in the first optical member 5, the hologram or the like can be formed thinner than, for example, a lens or the like. Is more effective, and the size and thickness of the first optical member 5 can be easily reduced.

Further, since the first optical member 5 is formed in the shape of a parallel plane plate as a whole, it is possible to prevent the occurrence of aberration and the like.
Therefore, it is preferable because good reproduction signal formation or farcus tracking signal formation can be performed. Further, the first optical member 5 is mounted so that the upper and lower surfaces thereof are accurately substantially perpendicular to the optical axis of the transmitted light, so that astigmatism can be prevented, and reproduction by spot blurring can be prevented. Signal degradation can be prevented.

As a material for forming the first optical member 5, a material having high light transmittance, such as glass or resin, can be used to prevent a decrease in light amount and to reduce the amount of light transmitted through the first optical member 5. This is preferable because the optical characteristics are not deteriorated. Particularly, glass is preferable as the material of the first optical member 5 because birefringence does not occur, and therefore, the characteristics of transmitted light can be favorably maintained. Further, among glass, it is preferable to use an optical glass such as BK-7, which has a small wavelength dispersion, that is, a large Abbe number, since it is possible to suppress the occurrence of spherical aberration due to wavelength fluctuation. Further, among these optical glasses, BK-7 is most suitable as a material for the first optical member 5 because of its low cost.

The first optical member 5 may be formed by joining a plurality of dice-shaped prisms in which optical elements are formed in advance in a straight line, or by forming a plate-shaped constituent material. It is preferable to use a method of forming an optical element at a predetermined position, bonding the respective plate-shaped materials together, and cutting the material into a predetermined shape, since good productivity can be obtained. In particular, the latter method is a preferable method because both high productivity and yield can be achieved.

In the present embodiment, the first optical member 5 is directly joined to the light emitting portion 1d provided on the side wall portion 1b of the first package 1. However, the first package 1 and the first optical member 5 are joined together. 5 may be provided separately. The distance between the light source 2 and the first optical member 5, which is a problem when there is a variation in the height of the package 1, can be adjusted more accurately by providing the first optical member. 5, the optical characteristics of the light guided to the light receiving element 3 can be better maintained, and accurate signal detection becomes possible.

Next, in FIG. 1, reference numeral 8 denotes a second package. The second package 8 includes a light source 9 for emitting light for a low-density optical disk and a light receiving element for receiving light reflected by the low-density optical disk. 8 and the side wall 8 provided so as to include those members.
b and the like. In the following, the second package 8 will be described in particular with respect to parts different from the first package 1.

First, it is preferable to use a material such as metal or ceramic as a material for forming the second package 8 because heat generated by the light source 9 can be satisfactorily emitted.

Among the metallic materials, metallic materials such as Cu, Al and Fe having high thermal conductivity, FeNi alloy and FeN
It is preferable to use an alloy material such as an iCo alloy. This is because these materials are inexpensive, have high heat dissipation, and also have an effect as an electromagnetic shield that blocks noise such as electromagnetic waves from a high-frequency superimposing circuit or the like. Among them, in particular, Fe, FeNi alloy, and FeNiCo alloy have low thermal resistance and good heat dissipation, so that the heat generated by the light source 8 can be efficiently released to the outside. Since these materials are low in cost, it is possible to provide the optical pickup device at low cost.

The oscillation wavelength of the light source 9 is 800 nm or less, so that the beam spot when the light emitted from the light source converges on the recording medium can be easily adjusted to a size about the pitch of a track formed on the recording medium. Is preferable. In particular, a light source having a longer oscillation wavelength than the light source 2 can be used as the light source 9. For example, when reproducing a CD, a beam spot having a sufficient size of about 780 nm can be formed on a low-density optical disk.

The structure of the second optical member 11 is substantially the same as that of the first optical member 5, but there is a case where there is a difference in the optical element formed on the inclined surface.
An optical path splitting means 12 composed of a half mirror, a polarization splitting film or the like is formed on the first slope 11a, and a reflecting means 13 for guiding incident light to the light receiving element 10 is formed on the second slope 11b. Is formed.

Here, the signal detection method is often different between the high-density optical disk and the low-density optical disk. Therefore, the arrangement of the light receiving sections in the light receiving element 10 is often different from the arrangement of the light receiving sections of the light receiving element 3. Therefore, the light receiving element 1
When a light such as a focus error signal is formed by the reflection means 13 when guiding light from the optical disc to the optical disc 0, the shape of the reflection means 13 is made different from the configuration of the reflection means 7, and the optimum shape for each optical disc is obtained. Performing signal formation is a preferable configuration because more accurate signal formation and operation control can be performed, and a more reliable optical pickup with less malfunction can be realized.

Next, the first package 1 and the first optical member 5
, That is, the space in which the light source 2, the light receiving element 3, and the like are arranged is preferably sealed. By adopting such a configuration, it is possible to prevent impurities such as dust and moisture from entering the inside of the package, so that the performance of the light source 11 and the light receiving element 70 can be maintained, and the optical characteristics of the emitted light can be maintained. Deterioration of characteristics can also be prevented. Further, an inert gas such as N ₂ gas, dry air or Ar gas may be sealed in a space sealed by the first package 1 and the first optical member 5.
First optical member 5 in contact with inside of first package 1
It is more preferable because dew condensation occurs on the surface of the light-emitting element and the like, thereby deteriorating the optical characteristics and deterioration of the characteristics due to oxidation of the light source 2 and the light-receiving element 3.

Next, reference numeral 15 denotes an optical path dividing means.
Reference numeral 5 has a function of guiding both the light from the light source 2 and the light from the light source 9 toward the optical disk. It is general to use a half mirror, a polarization splitting film, or the like as the optical path splitting means 14, but it is more preferable to transmit the light from the light source 2 at a high rate and reflect the light from the light source 9 at a high rate. It is desirable to have such properties. In such a case, loss of light in the optical path splitting unit 15 can be suppressed to a minimum, and therefore, light use efficiency can be improved. The improvement of the light use efficiency is achieved by the light source 2 or the light source 9.
It is possible to prolong the life of the light source 2 and the light source 9, thereby improving the reliability of the optical disk device equipped with the optical pickup. preferable.

As the optical path splitting means 15 having the above-described properties, it is preferable to use a reflecting means having a wavelength selecting function. The reflecting means having the wavelength selecting function has a function of transmitting light having a certain wavelength and reflecting light of another wavelength. In particular, in this embodiment, the reflecting means almost transmits light from the light source 2. By configuring the optical path splitting means 15 so as to substantially reflect the light from the light source 9, the light use efficiency of the light source 2 and the light source 9 can be set most efficiently. Accordingly, since a large load is hardly applied to either the light source 2 or the light source 9, the life of the light source 2 and the light source 9 can be averaged, and the life of the optical pickup can be extended, which is a preferable configuration.

In this embodiment, the quarter-wave plate 4 and the quarter-wave plate 14 are provided on the first optical member 5 and the second optical member 11, respectively. It may be provided at any position as long as it is between the end face on the collimator lens 16 side of the dividing means 15 and the optical disk. With this configuration, the number of quarter-wave plates required for two can be reduced by one, so that the productivity can be improved and a more inexpensive optical pickup can be obtained. Particularly, it is preferable to form the optical path dividing means 15 on the end face of the optical path dividing means 15 on the side of the collimator lens 16 in advance, since the number of steps can be reduced and the productivity can be further improved.

Reference numeral 16 denotes a collimator lens. The collimator lens 16 has a function of converting a diffusion angle of light emitted from the light sources 2 and 9 and converting light that was diffused light before incidence into substantially parallel light. I have. Reference numeral 17 denotes a condenser lens, and the condenser lens 1
Reference numeral 7 denotes a lens drive unit (not shown) for condensing incident light to form a beam spot on the optical disk.
Are supported so as to be movable in a focus direction and a tracking direction. Collimator lens 16
As a result, the amount of light incident on the condenser lens 17 can be increased, so that the light use efficiency is improved. Therefore, the light source 11 can be used at an output much lower than the maximum output, the life of the light source 11 can be prolonged, and the reliability of the optical pickup device can be improved.

Instead of using the collimating lens 16, for example, the first optical member 5 and the second optical member 11 may be provided with a function for converting the diffusion angle of light. In this case, since it is not necessary to provide the collimating lens 16, accurate positioning is not required, and the number of components can be reduced, so that productivity can be improved.

Next, the operation of the optical pickup device having such a configuration will be described with reference to the drawings.

Numeral 18 denotes a high-density optical disk mounted on a spindle motor (not shown). Two high-density optical disks 18 (hereinafter simply referred to as optical disks 18) having a disk substrate thickness of about 0.6 mm are laminated. Often molded. The luminous flux 2b emitted from the light emitting point 2a of the light source 2 passes through the optical path dividing means 6 formed on the first slope 5a of the first optical member 5, and is converted from linearly polarized light by the 波長 wavelength plate 4 into a circle. The polarization direction is changed to polarized light, and the polarized light enters the optical path splitting means 15. After being substantially transmitted through the optical path splitting means 15, the light is converted into a light flux 2c by a collimator lens 16 and condensed by a condenser lens 17 as a light flux 12d. The condensing lens 17 is designed to have a numerical aperture of about 0.6 so that it can be narrowed down to a minute spot so that data on the high-density optical disk 18 can be reproduced.

Next, referring to FIG.
The optical path of the forward light for reproducing 9 (hereinafter simply referred to as the optical disk 19) will be described. Here, the optical disk 19
Has a thickness of about 1.2 mm. The emitted light 9b emitted from the light emitting point 9a of the light source 9 passes through the optical path dividing means 12 provided on the first inclined surface 11a of the second optical member 11, and is converted from linearly polarized light by the quarter wavelength plate 14 into a circle. The polarization direction is changed to polarized light, and the polarized light enters the optical path splitting means 15. After being substantially reflected by the optical path dividing means 15, the collimator lens 16
Is converted into a luminous flux 9c by the condenser lens 17 and the optical disc 1 is
9 is converged as a light flux 12d.

At this time, the focal length L1 of the condenser lens 17 when reproducing the optical disk 19 is
Is set to be longer than the focal length L2 of the condensing lens 17 when reproducing. The difference between the focal lengths is 1.
0 mm or less, preferably 0.6 mm or less,
When playing multiple discs of different types,
It is almost unnecessary to drive the actuator holding the condenser lens 17 largely. Therefore, it is preferable because the focus position can be easily adjusted, and accordingly, the difference in the thickness of the substrate can be coped with very well.

As described above, since the lights from the plurality of light sources are focused on different positions on the recording medium, it is possible to reproduce the recording media having different substrate thicknesses by the same optical pickup device. Become. That is, an optical disc 19 such as a CD-ROM having a thickness of 1.2 mm and a high-density optical disc 18 such as a DVD formed by laminating a single plate having a thickness of 0.6 mm or both surfaces of the single plate with the same optical pickup device. It becomes possible to record and reproduce.

The focal lengths L1 and L2
Can be changed to some extent by increasing the movable range of an optical member such as a condenser lens. For example, it is possible to reproduce an optical disk having a high-density optical disk bonded thereto or an optical disk having a plurality of recording layers.

Next, the optical disk 18 and the optical disk 1
The optical path until the reflected light from No. 9 is detected, that is, the return path, will be described.

First, the case where the optical disk 18 is reproduced will be described. The reflected light from the optical disk 18 follows the same optical path as the outward path, passes through the optical path splitting means 15, and
The light is converted from circularly polarized light by the 波長 wavelength plate 4 into linearly polarized light orthogonal to the first polarization direction, and is incident on the optical path dividing means 6 formed on the first slope 5 a of the optical member 5. Since the optical path splitting means 6 is formed of a polarization splitting film here, the incident light is almost reflected and guided to the reflecting means 7. Although the reflection means 7 is formed of an optical element according to the purpose, here, an element for forming a focus error signal is provided.
Accordingly, the light reflected by the reflection means 7 is focused on the light receiving element 3 while forming a focus error signal, and detects a signal corresponding to data recorded on the high-density optical disk 18, a track error signal and a focus error signal.

Next, a case where the optical disk 19 is reproduced will be described. The reflected light from the optical disk 19 follows the same optical path as the outward path, is reflected by the optical path dividing means 15, is converted by the quarter-wave plate 14 from circularly polarized light to linearly polarized light orthogonal to the first polarization direction, and The light enters the optical path splitting means 12 formed on the first inclined surface 11a. Since the optical path splitting unit 12 is formed of a polarization splitting film here, the incident light is substantially reflected and guided to the reflecting unit 13. The reflecting means 13 is formed of an optical element according to the purpose. Here, an element for forming a focus error signal is provided. Accordingly, the light reflected by the reflection means 13 is focused on the light receiving element 10 while forming a focus error signal, and detects a signal corresponding to data recorded on the optical disc 19, a track error signal, and a focus error signal.

When a plurality of light sources are arranged at different positions in this manner, the wavefront aberrations generated in the light emitted from the respective light sources often differ greatly, and aberrations capable of correcting the wavefront aberrations are often used. It is necessary to use a lens having a correction function as a condenser lens, and as a result, it is generally necessary to use a plurality of condenser lenses corresponding to each light flux. In the present embodiment, this problem is avoided by optimizing the distance between the light emitting points 2a and 9a of the light sources 2 and 9, respectively, and the collimating lens. Therefore, this point will be described below.

FIG. 2 is a diagram showing the relationship between the light emitting point and the collimating lens in the infinite optical system according to the first embodiment of the present invention. In FIG. 2, L3 represents an effective focal length between the collimator lens 16 and the light emitting point 2a.
L4 indicates an effective focal length from the collimator lens 16 to the light emitting point 9a. FIG. 3 is a diagram showing the relationship between the amount of wavefront aberration and L3, L4 according to the first embodiment of the present invention. That is, when the ratio between L3 and L4 is changed, the amount of wavefront aberration generated at the time of incidence on the condenser lens
Are compared when there is a shift in the tracking direction by 500 μm (solid line) and when there is no shift in the tracking direction. Generally, the focusing lens during reproduction of the optical disc may shift up to about 500 μm in the tracking direction, and the amount of wavefront aberration allowed for effectively converging the light incident on the focusing lens on the optical disc is an RMS value. Considering that it is about 0.07λ or less (where λ indicates the wavelength of light), the amount of aberration is relatively large, and the light emission condition under which the light incident condition on the condenser lens 17 is tight is considered. Condensing lens 17 for light from point 9a
If the wavefront aberration amount at the maximum shift amount of (500 μm) is 0.07λ or less, the light incident from both light emitting points on the condenser lens 17 is independent of the shift amount of the condenser lens 17. It is considered that the light is converged on the optical disk. As a range that satisfies this condition, as is clear from FIG. 3, it is preferable that the ratio of L3 and L4 (L4 ÷ L3 = H, hereinafter expressed as H) is 0.55 <H <0.75. You can see that.

Further, under the same conditions, the wavefront aberration amount is RMS
If the value is 0.04λ or less, light from both light-emitting points incident on the condenser lens 17 will be very accurately converged on the optical disk regardless of the shift amount of the condenser lens 17. Conceivable. As a range that satisfies this condition, as is apparent from FIG. 3, the ratio (H) between L3 and L4
0.58 <H <0.70 is preferable because the signal characteristics can be further improved.

By arranging the optical systems so that the value of H is in the above-mentioned range, in an optical pickup having a plurality of light beams in the same optical system, the wavefront aberration of all the light beams can be reduced to the theoretical limit or less. Therefore, by using one condensing lens 17, any light beam can be condensed on the optical disk.

Accordingly, since only one objective lens 17 is required, it is possible to reduce the number of condenser lenses and to provide no means for switching the condenser lens, thereby reducing the size of the optical pickup and the number of parts. It is possible to improve the productivity, improve the reliability of the optical pickup by eliminating complicated mechanisms, improve the operation speed, and the like.

In this embodiment, the collimator lens 16
Although an infinite optical system using the optical system is used, a finite optical system as shown in FIG. 4 may be used. FIG. 4 is a diagram illustrating a relationship between a light emitting point and a condenser lens in the finite optical system according to the first embodiment of the present invention. In FIG. 4, L3
Represents the effective focal length from the condenser lens 17 to the light emitting point 2a, and L4 represents the effective focal length from the condenser lens 17 to the light emitting point 9a, except that it is the same as the infinite optical system. Further, the same definition can be applied to an optical pickup in which one is an infinite optical system and the other is a finite optical system.

Embodiment 2 Hereinafter, Embodiment 2 of the present invention will be described with reference to the drawings.

FIG. 5 is a sectional view of an integrated optical head according to the second embodiment of the present invention. In FIG. 5, the same reference numerals are given to members having the same configuration as in the first embodiment.

In FIG. 5, reference numeral 20 denotes a package, and the package 20 is a light source 2 for emitting light for the high-density optical disk 18 and a light source 9 for emitting light for the low-density optical disk 19.
And a substrate 20a on which a light receiving element 21 for receiving light reflected by the high-density optical disk 18 and the low-density optical disk 19 is mounted, and a side wall 20b provided so as to include those members. ing. The substrate 20a, the side wall 20b, and the terminals 20c that constitute the package 20 have substantially the same configuration as the substrate 1a, the side wall 1b, and the terminals 1c of the first package 1 except for the size.

Reference numeral 22 denotes an optical member.
And the light emitted from the light source 9 is guided to a predetermined optical path, and the light reflected back from the optical disk is returned to the light receiving element 2.
It has the function of leading to 1. The optical member 22 includes a first substrate 22d having a first inclined surface 22a, a second inclined surface 22b, and a third inclined surface 22c, and a second substrate 22e joined to an end face of the first substrate 22d on the light source side. ing.

The first slope 22a, the second slope 22b, and the third slope 22c are formed to have the slopes in the same direction. First slope 22a, second slope 2
With such a configuration of the 2b and the third inclined surface 22c, a predetermined optical path length can be obtained while shortening the height direction length of the first substrate 22d and thus the optical member 22. An optical pickup can be downsized while maintaining predetermined optical characteristics. In particular, when the package 20 including the optical member 22 and the like is mounted on a carriage (not shown), the center of gravity of the optical head exists at a position close to the mounting surface, so that high mounting accuracy can be realized. In addition, displacement during bonding can be suppressed at a high rate.

In addition, since various optical elements can be arranged at positions where light enters on each slope, predetermined optical characteristics can be imparted when the light entering the optical member 22 is transmitted.

In the case where light from a plurality of light sources is guided to the same optical path as shown in the present embodiment, the optical member 22 is used.
At least three or more inclined surfaces formed in the same direction are formed therein, and light from at least one light source
By reflecting the light more than once and passing through various optical members formed on the respective inclined surfaces, it is easy to optimize the optical characteristics of the light emitted from the light source 2 or the light source 9 before the light is emitted from the optical member 22. This is preferable because the design flexibility can be increased.

In this manner, the distance from the light source 2 or the light source 9 to the emission surface of the optical member 22 can be increased, and conversely, the distance from the optical member 22 to the recording medium can be further reduced. As a result, the size of the optical pickup can be reduced. Further, since it becomes possible to impart the optical characteristics necessary for irradiating the recording medium in the optical member 22, it is not necessary to separately provide various optical members in the optical path of the light emitted from the optical member 22,
It is possible to reduce the number of parts and the assembly cost.

The first slope 22a, the second slope 22b
By making the inclination angle of the third inclined surface 22c equal, a plurality of parallel flat plates in which a predetermined optical element is formed in advance are joined together and cut out at a predetermined angle, so that the optical member 22 can be easily formed with high precision. Can be produced, so that the productivity of the optical member 22 is greatly improved. Also, since the angle is determined in advance, the optical axis can be easily adjusted,
The time and process required for axis alignment can also be reduced.

The inclination angles of the first slope 22a, the second slope 22b, and the third slope 22c with respect to the incident light are from 30 ° to 30 °.
It is preferably in the range of 60 °, and more preferably in each case approximately 45 °. First slope 22a, second slope
The inclined surface 22b and the third inclined surface 22c are preferably provided at a predetermined distance from a relationship with an optical element formed on the inclined surface. If a predetermined distance is not provided between the optical elements, light that has transmitted slightly without being reflected will be
The possibility that the emitted light flux leaks into the optical path and becomes a stray light component or the like becomes more likely to occur.

Assuming that the predetermined distance is L, when the inclination angle of the slope is smaller than 30 °, the light is reflected by the first slope 22a and is incident on the second slope 22b, or is reflected by the second slope 22b. Only the difference 2L / √ (3) between the incident positions generated before the light is incident on the third slope 22c is at least when the thickness of the optical member 22 is increased, and when the angle is further increased, the same distance L is required. The difference between the incident positions thus generated results in an increase in the volume of the first optical member 5 correspondingly, which makes it difficult to miniaturize the optical pickup, which is not preferable.

Further, when the inclination angle of the slope is larger than 60 °, the volume of the optical member 22 also becomes large as described above, which makes it difficult to miniaturize the optical pickup.

Here, especially when the inclination angle is approximately 45 °, the light is reflected by the first slope 22a and is reflected by the second slope 22b.
Since the difference between the incident positions of the light incident on the optical member or the light reflected on the second inclined surface 22b and incident on the third inclined surface 22c can be almost eliminated, the miniaturization of the optical member 22 can be performed most efficiently. Therefore, the size of the optical pickup can be efficiently reduced, which is preferable.

Hereinafter, various optical elements existing in the optical member 22 will be described. Reference numeral 23 denotes a diffusion angle conversion unit. The diffusion angle conversion hologram 23 is provided on the end surface of the second substrate 22e on the light source side so as to match the optical axis of the light emitted from the light source 2. The function of reducing the diffusion angle, that is, converting the light path so that the light emitted from the light emitting point 2a of the light source 2 is emitted from a position farther than it looks, and shifts the light emitting point substantially in the opposite direction to the recording medium. ,
It has the function of increasing the optical path length from the light source to the recording medium. The diffusion angle conversion means 23 is preferably formed of a diffraction grating, especially a hologram, because it can transmit light with high efficiency. Especially as a hologram,
It is preferable to use one having a stepped cross section or a saw-tooth cross section of four or more steps, because light can be used with high efficiency and a decrease in the amount of light can be prevented.

Reference numeral 24 denotes a filter having wavelength selectivity. The filter 24 has a function of substantially transmitting light guided from the light source 2 and substantially reflecting light guided from the light source 9.

Since the filter 24 is formed on the first inclined surface 22a, the light guided from the light source 9 can be reflected without substantially hindering the light emitted from the light source 2. The light emitted from the light source 9 can be guided to the recording medium at a high rate. Therefore, recording or reproduction on the recording medium can be performed without increasing the amount of light emitted from the light sources 2 and 9, and the light sources 2 and 9 are operated by operating the light sources 2 and 9 in a high output state. Can be shortened. Further, since the light source 2 and the light source 9 can be used in a low output state, the temperature of the light source 2 and the light source 9 hardly rises, so that the oscillation wavelength of the light source 2 and the light source 9 hardly shifts with the temperature change. . Accordingly, it is possible to provide a high-performance optical pickup capable of forming a focus more accurately.

Reference numeral 25 denotes a polarized light separating film. The polarized light separating film 25 has a function of transmitting light having a specific polarization direction and reflecting light having other polarization directions. Here, the polarization separation film 25 is formed by the light emitted from the light source 2 and the light source 9.
It is formed so as to transmit the polarization component and reflect the P polarization component. The polarized light separating film 25 can guide the light passing through the recording medium without substantially reducing the amount thereof, thereby improving the light use efficiency and extending the life of the light sources 2 and 9. This is preferable because

Reference numeral 26 denotes a 波長 wavelength plate.
Since the structure and operation are almost the same as those of the ４ wavelength plate 4 and the 波長 wavelength plate 14 shown in the first embodiment, the description is omitted.

Reference numeral 27 denotes a diffusion angle conversion means. The diffusion angle conversion means 27 is provided on an end face of the second substrate 22e on the light source side so as to match the optical axis of light emitted from the light source 9. The light path is changed so that the light emitted from the light-emitting point 9a of the light source 9 is emitted from a position closer to the eye than when viewed, and substantially in the direction approaching the recording medium. Shift the light emitting point. Thereby, the light emitting point of the light source 9 apparently moves from the light emitting point 9a to the light emitting point 9b, and thus has a function of shortening the optical path length from the light source 9 to the recording medium. The diffusion angle conversion means 27 is preferably formed of a diffraction grating, especially a hologram, because it can transmit light with high efficiency. In particular, it is preferable to use a hologram having a stepped cross-section or a saw-tooth cross-section of four or more steps because light can be used with high efficiency and a decrease in the amount of light can be prevented.

Reference numeral 28 denotes a plurality of beam forming means. The plurality of beam forming means 28 has a function of separating incident light into a plurality of light beams and reflecting the light.
The light that has passed through the filter 7 is separated into three luminous fluxes and a filter 2
Reflecting toward 4. The multiple beam forming means 28
Forming with a diffraction grating is preferable because a plurality of light beams can be efficiently formed. Here, the configuration is such that three light fluxes of 0-order light and ± 1st-order light generated by the diffraction grating are mainly formed. The plurality of luminous fluxes formed here are applied to a predetermined position of a track of the low-density optical disk 19, and the amount of the returned light is compared to perform tracking of the low-density optical disk 19 by a so-called three-beam method. Subject to the method.

Reference numerals 29 and 30 denote reflecting means.
Represents the light reflected by the polarization separation film 25,
Has a function of reflecting light reflected by the reflection means 29 in a predetermined direction, and is formed of a metal material having high reflection such as Ag, Au, Cu, or a plurality of dielectric materials having different refractive indexes. Is preferred.

Reference numeral 31 denotes a diffusion angle conversion means. The diffusion angle conversion means 31 is formed on the third inclined surface 22c of the first substrate 22d.
The function is to change the diffusion angle of light in the diffusion direction to the convergence direction and to reflect the light beam in the convergence direction as it is.

The diffusion angle conversion means 31 is preferably formed of a diffraction grating, especially a reflection type hologram, because it can transmit light with high efficiency. In particular, it is preferable to use a reflection hologram having a stepped cross section or a sawtooth cross section of four or more steps, because light can be used with high efficiency and a decrease in the amount of light can be prevented.

In the present embodiment, the reflection type hologram 31 reflects most of the light beam formed by the light emitted from the light source 2 as the zero-order light, and reflects the light beam formed by the light emitted from the light source 9. Is diffracted into + 1st-order light. As a result, the light emitting point position of the light emitted from the light source 9 moves forward (from the recording medium), so that the light flux from the light source 9 diverges on the light receiving element 21, and the detection, focusing, and tracking of the RF signal are performed. Since it is possible to prevent signal formation from becoming difficult, it is possible to realize a high-performance optical pickup capable of reliably forming an accurate signal.

Reference numeral 32 denotes a signal forming means.
Is provided on the end face of the second substrate 22e on the light source side, guides the light guided from the diffusion angle conversion means 31 to a predetermined position of the light receiving element 21 and imparts a predetermined characteristic to the incident light flux, It has a configuration capable of forming signals for focusing and tracking.

Numeral 33 is a light receiving means. The light receiving means 33 is a part of the light emitted from the light source 2 which is reflected without passing through the filter 24 and the light emitted from the light source 9 which is not reflected by the filter 24. The output of the light source 2 and the light source 9 is controlled by receiving the light transmitted through the light source 2 and feeding back the signal to the power control circuit of the light source 2 and the light source 9.

Next, the reason why the optical member 22 is formed separately on the first substrate 22d and the second substrate 22e will be described.
The first substrate 22d has a plurality of slopes, and various optical elements are arranged at positions parallel to the slopes. Therefore, the various optical elements provided on the first substrate are arranged obliquely with respect to the optical axis of the incident light. Therefore, if an optical element having a high angle dependency, such as a hologram, is formed in the first substrate 22d, unless the alignment is performed with a considerably high accuracy, the tolerance due to the angle increases, and the characteristics of light traveling toward the recording medium deteriorate. The possibility of doing it is very large. This undesirably leads to deterioration of signal characteristics and, as a result, causes the performance of the optical pickup device to deteriorate. Therefore, in the present embodiment, the diffusion angle conversion means 23 and 27, which are considered to have particularly high angle dependence, are formed on the second substrate 22e provided separately from the first substrate 22d, and the light source 2 and the Diffusion angle conversion means 23 and 27 are arranged to be substantially perpendicular to the optical axis of the light emitted from the light source 9.

With such an arrangement, it is possible to almost prevent deterioration of the characteristics of light guided to the recording medium, and to provide a high-performance optical pickup device with little deterioration in signal characteristics. It is preferable because it can be used.

It is preferable that the various optical elements provided on the second substrate 22e are formed only on one surface of the second substrate 22e.

This is because these optical elements are formed by a physical or chemical method such as etching through a mask of a predetermined shape, and the number of masks can be reduced by forming them on only one side. Since the number of times of etching can be further reduced, the number of steps can be reduced.
In addition, since it is not necessary to turn over the master of the substrate 22e, it is possible to omit a plurality of alignments. Therefore, productivity can be greatly improved and manufacturing cost can be reduced.

In this embodiment, the diffusion angle conversion means 2
3, 27 and the signal forming means 32 are formed on the end face on the light source side of the second substrate 22e.

It is preferable that the space surrounded by the package 20 and the optical member 22 be hermetically closed as in the first embodiment.

As described above, by adopting a configuration in which light from a plurality of light sources having different oscillation wavelengths is made incident on an optical member on which a plurality of optical elements are formed and guided to a predetermined optical path, each of the conventional devices Since a plurality of optical elements and the like provided for each of the light sources can be integrated into one, the size of the entire optical pickup can be significantly reduced as compared with an optical pickup arranged in a distributed manner, and each light source can be reduced. This eliminates the need for positioning between optical elements, greatly improving productivity, and further minimizing the mounting error of each optical element, thereby realizing good optical characteristics. Since the loss of light due to the mounting error of each optical element can be suppressed to a minimum, an optical pickup with good light use efficiency can be realized.

Further, at least one of the light emitted from the light source 2 and the light emitted from the light source 9 is reflected a plurality of times by the optical member 22 and guided to a predetermined optical path, so that the optical member 22
Can be reduced, and the optical path length after exiting the optical member 22 can be reduced as compared with the case where the optical pickup is guided without reflection, so that the optical pickup can be reduced in size and thickness.

Further, the light from the light source 2 and the light from the light source 9 are made incident on the optical member 22 on which a plurality of optical elements are formed and guided to a predetermined optical path. , Both can be accurately guided to each recording medium, and it is not necessary to form a plurality of optical systems corresponding to a plurality of light sources using different optical members, thereby improving the productivity by reducing the number of parts and improving the productivity. Can be simplified.

The operation of the optical pickup having the above configuration will be described. When the recording medium is the high-density optical disk 18, recording or reproduction is performed using the light emitted from the light source 2. In this case, the diffusion angle of the light emitted from the light source 2 is reduced by the diffusion angle conversion means 23, that is, the spread of the light is reduced.

Most of the light emitted from the light source 2 can be transported toward the high-density optical disk 18 by the diffusion angle conversion means 23. , A sufficient amount of light on the plate surface can be obtained. Therefore, it is possible to provide an optical pickup that can perform both recording and reproduction well.

[0111] Further, since light entering the portion other than the predetermined optical path of the optical member 22 can be reduced,
The stray light component in the optical member 22 is reduced, so that it is possible to prevent the signal component from being deteriorated due to the stray light being incident on the light receiving element 21 or the like.

The light, the spread of which is reduced by the diffusion angle conversion means 23, almost passes through the filter 24 and almost also passes through the polarization separation film 25 provided thereafter, and is 1/1.
The light enters the four-wavelength plate 26.

When the light passes through the quarter-wave plate 26, the light that has been linearly polarized light is converted into circularly polarized light, and if there is a collimator lens, the light passes through the collimator lens 16 and is converted into parallel light. Therefore, when there is no light, the light directly enters the condenser lens 17 and is converged on the high-density optical disk 18.

The light reflected back from the high-density optical disk 18 is again incident on the quarter-wave plate 26, and when passing through it, is orthogonal to the polarization direction when the light source 2 is emitted from the circularly polarized light. The light is converted into linearly polarized light and enters the polarization separation film 25. Here, unlike the direction, the polarization direction is now different, so that the light is reflected by the polarization separation film 25 and is reflected by the reflection means 2.
The light enters the divergence angle conversion means 31 via 9, 30. The light incident by the divergence angle conversion means 31 is reflected without being diffracted, and is reflected by the signal forming means 32.
A light beam having a predetermined shape is formed at a predetermined position on the light receiving element 21. Based on the light incident on the light receiving element 21, both an RF signal and a focus tracking signal are formed. Optimal control is performed.

When the recording medium is the low-density optical disk 19, recording or reproduction is performed using the light emitted from the light source 9. In this case, the spread of the light emitted from the light source 9 is converted by the diffusion angle conversion means 27 from the diffusion direction to the convergence direction, that is, from the diffused light to the converged light.

The light converted into the convergent light by the diffusion angle conversion means 27 is almost reflected by the filter 24 and almost passes through the polarization separation film 25 provided thereafter, and is incident on the １ ／ wavelength plate 26.

When passing through the quarter-wave plate 26, the light that has been linearly polarized light is converted into circularly polarized light, and if there is a collimator lens, it passes through the collimator lens 16 and is converted into parallel light. Therefore, when there is no light, the light directly enters the condenser lens 17 and is converged on the low-density optical disk 19.

The light reflected by the low-density optical disk 19 and returned again enters the quarter-wave plate 26, and when passing through it, is orthogonal to the polarization direction when the light source 9 is emitted from the circularly polarized light. The light is converted into linearly polarized light and enters the polarization separation film 25. Here, unlike the direction, the polarization direction is now different, so that the light is reflected by the polarization separation film 25 and is reflected by the reflection means 2.
The light enters the divergence angle conversion means 31 via 9, 30. The light incident by the divergence angle conversion means 31 is almost diffracted into + primary light and reflected, and the light that was diffused before being incident is converted into convergent light. The light enters the signal forming means 32.

A light beam having a predetermined shape is formed at a predetermined position on the light receiving element 21 by the signal forming means 32.
1 based on the light incident on the
Both signals for tracking are formed, and information is reproduced and optimal control of the optical pickup is performed.

Even when a plurality of light sources are arranged in the same package, the wavefront aberration generated in the light emitted from each light source often differs greatly as in the first embodiment. Since the distance between the light emitting points 2a and 9a of the light sources 2 and 9 and the collimating lens is optimized, this point will be described below. Portions having substantially the same configuration as in the first embodiment are denoted by the same reference numerals.

FIG. 6 is a diagram showing a relationship between a light emitting point and a collimating lens in an infinite optical system according to Embodiment 2 of the present invention. In FIG. 6, L5 indicates the effective focal length between the collimator lens 16 and the virtual light emitting point 2b.
Reference numeral 6 denotes an effective focal length from the collimator lens 16 to the virtual light emitting point 9b. FIG. 7 is a diagram showing the relationship between the amount of wavefront aberration and L5, L6 depending on whether or not the objective lens is shifted according to the second embodiment of the present invention. That is, L
When the ratio of 3 to L4 is changed, the amount of wavefront aberration generated at the time of incidence on the condenser lens is shifted by 500 μm in the tracking direction of the condenser lens 17 (solid line), and when there is no shift in the tracking direction. This is what is being compared. Generally, the focusing lens during reproduction of the optical disc may shift up to about 500 μm in the tracking direction, and the amount of wavefront aberration allowed for effectively converging the light incident on the focusing lens on the optical disc is an RMS value. Considering that it is about 0.07λ or less (where λ indicates the wavelength of light), the amount of aberration is relatively large, and the light emission condition under which the light incident condition on the condenser lens 17 is tight is considered. If the amount of wavefront aberration when the shift amount of the condenser lens 17 with respect to the light from the point 9a is the maximum (500 μm) is 0.07λ or less, the light from both emission points enters the condenser lens 17. It is considered that the light is converged on the optical disk regardless of the shift amount of the condenser lens 17. As a range satisfying this condition, as is apparent from FIG.
Ratio of L5 to L6 (L6 ÷ L5 = H, hereinafter expressed as H)
Is preferably 0.55 <H <0.75.

Under the same conditions, the wavefront aberration amount is RMS
If the value is 0.04λ or less, light from both light-emitting points incident on the condenser lens 17 will be very accurately converged on the optical disk regardless of the shift amount of the condenser lens 17. Conceivable. As a range that satisfies this condition, as is apparent from FIG. 3, the ratio (H) between L3 and L4
0.58 <H <0.70 is preferable because the signal characteristics can be further improved.

By arranging the optical system so that the value of H is within the above-mentioned range, in an optical pickup having a plurality of light beams in the same optical system, the wavefront aberration of all the light beams can be reduced to the theoretical limit or less. Therefore, by using one condensing lens 17, any light beam can be condensed on the optical disk.

Accordingly, since only one objective lens 17 is required, it is possible to reduce the number of condenser lenses and to provide no means for switching the condenser lenses, thereby reducing the size of the optical pickup and the number of parts. It is possible to improve the productivity, improve the reliability of the optical pickup by eliminating complicated mechanisms, improve the operation speed, and the like.

In this embodiment, the collimator lens 16 is used.
Although an infinite optical system using the optical system is used, a finite optical system may be used. In this case, a space for disposing the collimator lens is not required as compared with the infinite system, so that the size of the entire optical pickup can be reduced.

Embodiment 3 Hereinafter, Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 8 is a sectional view of an integrated optical head according to Embodiment 3 of the present invention, and FIG. 9 is a detailed sectional view of an optical part according to Embodiment 3 of the present invention. In FIGS. 8 and 9, members having the same configurations as those of the first and second embodiments are denoted by the same reference numerals.

8 and 9, reference numeral 40 denotes a package, and the package 40 is a light source for emitting light for the high-density optical disk 18, a light source 9 for emitting light for the low-density optical disk 19, the high-density optical disk 18, and the like. The light receiving means 58 and 59 for receiving the light reflected by the low-density optical disk 19 are formed by a substrate portion 40a on which the light receiving means 58 and 59 are placed and a side wall portion 40b provided so as to include those members. Substrate 40a, side wall 4 constituting package 40
Ob and terminals 40c have substantially the same configuration as the substrate 1a, side wall 1b, and terminals 1c of the first package 1 except for the size.

Next, the light source mounting section 42 on which the light sources 2 and 9 (hereinafter collectively referred to as light sources) are mounted will be described. The light source mounting portion 42 has a rectangular parallelepiped shape or a plate shape, and each light source is attached to an upper surface or a side surface thereof. The light source mounting portion 42 is provided with a separate member or the substrate portion 40a and the side wall portion 4 on the substrate portion 40a or the side wall portion 40b.
0b, and has a function of mounting each light source and releasing heat generated by each light source.

The light source 2 and the light source 9 are arranged on the side surface 42a of the light source mounting portion 42 at substantially the same height from the bottom surface of the light source mounting portion 42. That is, a straight line connecting the light emitting point 2a of the light source 2 and the light emitting point 9a of the light source 9 is substantially perpendicular to the surface of the recording medium.

With such an arrangement, the light emitted from the light source 2 is transmitted to the first optical member 41 and the fourth optical member 5.
And a second plane including an optical axis formed when the light emitted from the light source 9 passes through the first optical member 41 and the fourth optical member 53. And a third plane including an optical axis formed when the light emitted from the light source 9 passes through the third optical member 49 can be used as a light propagation surface. In other words, not only the plane perpendicular to or parallel to the surface of the recording medium is used as the propagation plane, but any plane can be used as the propagation plane.

At this time, by making the first plane and the second plane substantially parallel to each other, a part of the light related to the optical axis that originally forms the first plane forms the second plane. The light related to the optical axis is incident on the optical element to be incident and becomes a stray light component, or conversely, a part of the light related to the optical axis that originally constitutes the second plane constitutes the first plane. Since it is possible to prevent the light related to the optical axis from being incident on the optical element to be incident and becoming a stray light component, the optical characteristics of the optical pickup having such a configuration can be improved, and the high performance light can be obtained. Pickup can be provided.

By forming such a three-dimensional propagation surface, the space utilization efficiency of each optical member can be improved. This makes it possible to reduce the size of each optical member, which also contributes to reducing the size of an optical pickup equipped with these optical members.

Further, when such space is used three-dimensionally, the frequency of use in the in-plane direction parallel to the recording medium is made higher than the frequency of use in the in-plane direction non-parallel to the storage medium. Since the thickness of each optical member can be reduced, the thickness of the optical pickup can be reduced. This makes it possible to provide an optical pickup particularly suitable for an optical disc drive mounted on an information terminal such as a portable personal computer.

In this embodiment, the light source 2 and the light source 9 are arranged substantially perpendicular to the surface of the recording medium.
The arrangement of these light sources is non-parallel to the surface of the recording medium,
That is, the above-mentioned object can be achieved by arranging the recording medium so as to have a distribution in a height direction perpendicular to the surface of the recording medium.

Further, the material forming the light source mounting portion 42 is a line.
The expansion coefficient is that of each light source (about 6.5 × 10^-6/ ℃)
Material is preferable. Specifically, the coefficient of linear expansion is 3 to 10 ×
10 ^-6/ C, thermal conductivity is 100W / mK or more
Quality, such as AlN, SiC, T-CBN, Cu / W, C
u / Mo, Si, etc., especially when using a high output light source
When thermal conductivity must be very high,
It is preferable to use earmond or the like.

When the linear expansion coefficients of the light sources 2 and 9 and the light source mounting portion 42 are set to be the same or close to each other, the occurrence of distortion between each light source and the light source mounting portion 42 can be suppressed. Therefore, it is possible to prevent inconveniences such as detachment of the attachment portion between each light source and the light source mounting portion 42 and cracking of each light source.

Further, by making the heat conductivity of the light source mounting portion 42 as large as possible, the heat generated in each light source can be efficiently released to the outside, so that the temperature of each light source rises and the light emitted from each light source is emitted. The light wavelength shifts, the convergence position of the light on the recording medium is slightly different, and many noise components are mixed in the reproduced signal, and the output of each light source is reduced. It is possible to prevent inconveniences such as the inability to normally perform the recording / reproducing operation on the medium, the shortening of the life of each light source, and in the worst case, the destruction of each light source.

In the present embodiment, the light source 2 and the light source 9 are arranged at substantially the same height from the bottom surface of the light source mounting portion 42 on the side surface 42a of such a light source mounting portion 42.

Reference numeral 41 denotes a first optical member.
Has a function of guiding the light emitted from the light source 2 and the light source 9 to a predetermined optical path and guiding the light reflected by the optical disk and returned to the predetermined optical path. First optical member 41
Has a first slope 41a and a second slope 41b, and preferably has a configuration in which a surface on which light is incident and a surface on which light is emitted are substantially parallel. By forming in this manner, generation of astigmatism or the like with respect to incident light can be suppressed, so that deterioration of optical characteristics of transmitted light can be prevented. Further, various optical elements are formed on the first slope 41a and the second slope 41b.

Hereinafter, various optical elements existing in the first optical member 41 will be described. First, on the first slope 41a,
A reflection film 43 and a reflection film 44 are formed. Reflective film 4
Numeral 3 has a function of reflecting light emitted from the light source 2 in a predetermined direction, and the reflection film 44 has a function of reflecting light emitted from the light source 9 in a predetermined direction. .
As a material forming the reflection films 43 and 44, a metal material having high reflection such as Ag, Au, Cu, or a plurality of dielectric materials having different refractive indexes is used, and the respective materials are alternately formed in a plurality of layers. It is preferable that it is formed by providing.

In this embodiment, the reflection film 43 and the reflection film 44 are provided separately. However, the reflection film 43 and the reflection film 44 may be formed on substantially the entire first slope 41a as one large reflection film. In this case, the process of forming the reflective film using the mask can be omitted and the mask for forming the reflective film can be omitted, so that the productivity can be improved and the manufacturing cost can be reduced. Can be.

The polarization separation films 45 and 46 are formed on the second inclined surface 41b. Light emitted from the light source 9 and reflected by the reflection film 44 enters the polarization separation film 46, and light emitted from the light source 2 and reflected by the reflection film 43 enters the polarization separation film 45. . These polarization separation films 45 and 46 transmit light having a specific polarization direction,
It has a function of reflecting light having other polarization directions. It is more accurate that such polarization separating films 45 and 46 are formed by using a plurality of dielectric materials having different refractive indices and by alternately providing a plurality of layers of each material.
It is preferable because S separation can be performed. In particular, here, it is formed so as to transmit the S-polarized light component emitted from the light source 2 and the light source 9 and reflect the P-polarized light component.

The polarization splitting films 45 and 46 can guide the amount of light passing through to the recording medium without substantially reducing the amount thereof, so that the light use efficiency can be improved and the light source 2 and the light source 9 can be improved. Is preferable because a predetermined surface light amount can be obtained with a small output, and a long life of each light source can be realized.

In the present embodiment, the polarization separation film 4
5 and 46 are provided separately, but may be formed as a single large reflective film on almost the entire second inclined surface 41b. In this case, the process of forming the polarization separation film using the mask can be omitted, and the mask for forming the polarization separation film can be omitted.
The productivity can be improved and the manufacturing cost can be reduced.

In this embodiment, the polarization splitting film is used as a means for separating outgoing light and return light. However, these may be separated by using a separating means such as a half mirror according to the required surface light quantity. Is also good.

Next, the second optical member 47 will be described.
The second optical member 47 is provided on the upper surface of the first optical member 41, and is joined to the first optical member 41 with an ultraviolet curing resin, an epoxy resin, or the like. The second optical member is
Each of the opposing surfaces is formed by a substantially parallel light-transmitting substantially parallel flat plate, and light 1 from the light source 9 is transmitted therethrough.
Diffusion angle conversion means 48 is formed on the end face.

The diffusion angle conversion means 48 is provided on the end surface of the second optical member 47 on the side opposite to the light source 9 so as to be aligned with the optical axis of the light emitted from the light source 9, and is incident from the light source 9. It has a function of making the diffusion angle of light negative, that is, a function of changing the optical path so that light emitted from the light emitting point 9a of the light source 9 is emitted from a position closer to the eye than it looks. The light emitting point is shifted in the direction approaching the medium.
Thereby, the light emitting point of the light source 9 moves from the true light emitting point 9a to the apparent light emitting point 9b, and thus has a function of apparently shortening the optical path length from the light source 9 to the recording medium. The diffusion angle conversion means 48 is preferably formed of a diffraction grating, especially a hologram, because it can transmit light with high efficiency. In particular, a hologram having a stepped cross section or a sawtooth cross section of four or more steps is used.
It is particularly preferable because light can be used with high efficiency and a decrease in the amount of light can be prevented.

Next, the third optical member 49 will be described.
The third optical member 49 is provided on the upper surface of the second optical member 47, and the second optical member 47 and the third optical member 49 are joined by a joining material such as an ultraviolet curing resin or an epoxy resin.

The third optical member 49 guides the light emitted from the light source 2 and the light source 9 and guided through the first optical member 41 and the second optical member 47 to a predetermined optical path and is reflected by the optical disk. It has a function of guiding the returned light to a predetermined optical path.

Furthermore, the third optical member 49 is provided on the first slope 4
9a and a second inclined surface 49b, and in particular, a surface on which light is incident and a surface on which light is emitted are substantially perpendicular to the optical axis of light,
In addition, it is preferable that the respective surfaces be substantially parallel to each other. By forming in this manner, generation of astigmatism or the like with respect to incident light can be suppressed, so that deterioration of optical characteristics of transmitted light can be prevented.

The first slope 49a and the second slope 49b
Are formed so as to be substantially parallel to each other and to be inclined in a direction substantially perpendicular to the optical axis of light passing through the first optical member 41 and the second optical member 47.

Further, the first slope 49a and the second slope 4
Various optical elements are formed in 9b.

A plurality of beam forming means 50 is provided on the first slope 49a. The multiple beam forming means 50 includes a polarization separation film 50a that reflects or transmits light in accordance with the polarization direction, and a beam separation unit 50b that separates incident light into a plurality of light fluxes and reflects the light. And the light that has passed through the diffusion angle conversion means 48 almost passes through the polarization separation film 50a,
Incident on. Then, the incident light is converted into a beam splitter 50.
At b, the light is separated and reflected into a plurality of light beams.

Here, it is preferable to form the beam splitting section 50b with a diffraction grating because a plurality of light beams can be efficiently formed. Here, the configuration is such that three light fluxes of 0-order light and ± 1st-order light generated by the diffraction grating are mainly formed.

The plurality of luminous fluxes formed here are applied to a predetermined position on the track of the low-density optical disk 19, and the amount of returned light is compared to perform tracking of the low-density optical disk 19 by a so-called three-beam method. The tracking method is called.

When the three-beam method is not used as the tracking method, a plurality of beam forming means need not be provided.

A filter 51 having wavelength selectivity is formed on the second slope 49b. The filter 51 has a function of transmitting approximately 80% or more of the light guided from the light source 2 and reflecting approximately 80% or more of the light guided from the light source 9.

Since the filter 51 is formed on the first inclined surface 49a, the light guided from the light source 9 can be reflected without substantially hindering the light emitted from the light source 2, so that the light source 2 and the light source 9 can be guided to the recording medium at a high rate. Therefore, recording or reproduction on a recording medium can be performed without increasing the amount of light emitted from the light source 2 and the light source 9,
It is possible to prevent the life of the light sources 2 and 9 from being shortened by operating the light sources 2 and 9 in a high output state. Further, since the light source 2 and the light source 9 can be used in a low output state, the temperature of the light source 2 and the light source 9 hardly rises, so that the oscillation wavelength of the light source 2 and the light source 9 hardly shifts with the temperature change. . Accordingly, it is possible to provide a high-performance optical pickup capable of forming a focus more accurately.

The light from the light source 2 and the light from the light source 9 are guided to the substantially same optical axis by the third optical member 49.

The light path from the light from the light source 9 to the third optical member, after being reflected by the plural beam forming means 50 and then to the filter 51, is relative to the plane including the light traveling in the first optical member 41. Are formed so as to proceed in a substantially vertical direction.

Reference numeral 52 denotes a １ ／ wavelength plate.
Has a function of converting the polarization directions of both the light from the light source 2 transmitted through the filter 51 and the light from the light source 9 reflected by the filter 51 from linearly polarized light to elliptically polarized light.

The quarter-wave plate 52 may be a plate having a predetermined thickness as shown in this embodiment, or may be formed as a thin film.

Next, the fourth optical member 53 will be described.
The fourth optical member 53 is bonded to the bottom surface of the first optical member 41 with a photocurable resin, an epoxy resin, or the like, and has a function of guiding return light reflected by the recording medium to a predetermined position. I have. The fourth optical member 53 has a first slope 53a and a second slope 53b, and an optical element according to the purpose is formed on each slope.

In the present embodiment, the first slope 53
Light path dividing means 54 and 55 are formed in a. The light path dividing means 54 has a function of transmitting or reflecting the light emitted from the light source 2 and reflected by the high-density optical disk 18 and returned.
Has a function of transmitting or reflecting light emitted from the light source 9 and reflected by the low-density optical disk 19 and returned. Here, it is preferable to use a half mirror so that the amount of light transmitted and the amount of light reflected by both the optical path dividing means 54 and the optical path dividing means 55 are substantially the same.

The reflection films 56 and 57 are formed on the second slope 53b. The reflection film 56 has a function of reflecting the light reflected by the light path dividing means 54 and entering the light and guiding it to a predetermined position, and the reflection film 57 reflects the light reflected by the light path dividing means 55 and incident. It has the function of reflecting and guiding to a predetermined position. The reflection films 56 and 57 are made of Ag, Au,
It is preferably formed of a metal material having high reflection such as Cu or a plurality of dielectric materials having different refractive indexes.

Numerals 58 and 59 denote light receiving means. The light receiving means 58 receives the light transmitted through the optical path dividing means 54 and the light reflected by the optical path dividing means 54 and then reflected by the reflection film 56. The means 59 receives the light transmitted through the light path dividing means 55 and the light reflected by the reflection film 57 after being reflected by the light path dividing means 55.
A required number of various light receiving sections are formed in required positions and at necessary positions for forming a signal, a tracking signal, and a focusing signal.

Further, it is preferable that the light sources 2, 9 and the light receiving means 56, the optical members 41, 47, 49, etc. exist in a closed space as in the first embodiment.

As described above, by adopting a configuration in which light from a plurality of light sources having different oscillation wavelengths is made incident on an optical member on which a plurality of optical elements are formed and guided to a predetermined optical path, each of the conventional devices Since a plurality of optical elements and the like provided for each of the light sources can be integrated into one, the size of the entire optical pickup can be significantly reduced as compared with an optical pickup arranged in a distributed manner.

In addition, since it is not necessary to adjust the position of each optical element with respect to each light source, productivity is greatly improved, and furthermore, mounting errors of each optical element can be suppressed to a minimum, so that good optical characteristics can be achieved. Characteristics can be realized.

Further, the loss of light due to the mounting error of each optical element can be suppressed to a minimum, so that an optical pickup with good light use efficiency can be realized.

Further, at least one of the light emitted from the light source 2 and the light emitted from the light source 9 is reflected a plurality of times by the optical members 41 and 49 and guided to a predetermined optical path, thereby reducing the size of the optical member 22. And the optical path length after exiting the optical members 41 and 49 can be shortened as compared with the case where the light is guided without reflection, so that the optical pickup can be reduced in size and thickness.

Further, the light from the light source 2 and the light source 9 is made incident on the optical members 41, 47, and 49 on which a plurality of optical elements are formed, and is guided to a predetermined optical path. The light for 19,
Both can be accurately guided to each recording medium, and it is not necessary to form a plurality of optical systems corresponding to a plurality of light sources by using different optical members. The alignment of the constituent members can be simplified.

Next, a plurality of slopes provided on each optical member will be described. First, the first slope 41a and the second slope 41b provided on the first optical member 41 are formed to have the same slope at the same slope angle and in the same direction.

The first and second slopes 53a and 53b provided on the fourth optical member 53 are formed so as to have the same slope at the same slope angle and in the same direction. When the inclination angle of each slope is substantially 45 degrees with respect to the first slope 41a and the second slope 41b formed on the one optical member 41, the first slope 41a and the second slope 41b are formed so as to form an angle of substantially 90 degrees. Have been.

Further, the first slope 49a of the third optical member 49 is provided.
The second inclined surface 49b has the same inclined angle in the same direction as the second inclined surface 49b, and has a non-parallel relationship with the respective inclined surfaces of the first optical member 41 and the fourth optical member 53. Is formed.

As described above, since the inclination direction of the slope formed on the optical member is set to be the same direction for each optical member, a plurality of plate members on which predetermined optical elements are formed in advance can be used. Since the optical member can be easily manufactured by combining and joining and cutting out at a predetermined angle, the productivity of the optical member can be improved. Further, since the angle can be determined in advance, the optical axis can be adjusted at the same time, and the time and process required for axis alignment can be reduced.

Further, since various optical elements can be arranged at positions where light is reflected on each slope, predetermined optical characteristics can be imparted when light entering each optical member passes therethrough. .

In particular, as shown in the present embodiment, when light from a plurality of light sources is guided to the same optical path, it is formed in the first optical member 41, the third optical member 49, and the fourth optical member 53. By providing at least two or more inclined surfaces, reflecting light from at least one light source twice or more, and passing through various optical members formed on each of the inclined surfaces, the light source 2 is provided.
Alternatively, it is preferable because the optical characteristics of the light emitted from the light source 9 can be easily optimized in each optical member.

In addition, by making the inclination direction of the inclined surface different for each optical member, the distance from the light source 2 or the light source 9 to the exit surface of the third optical member 49 can be increased. The distance from 49 to the recording medium can be further reduced, and the size of the optical pickup can be reduced.

Furthermore, since the inclination direction of the slope is different for each optical member, the direction in which light is reflected is also different, so that the width of the optical member is smaller than when the light is guided in a fixed direction. Can be smaller. As a result, the width of the package 40 on which these optical members are provided can be reduced, and the size of the carriage (not shown) to which the package 40 is attached can be reduced.
The size of the drive device on which the pickup is mounted can be reduced.

By the way, in the optical axis direction of the light emitted from the third optical member 49, the thickness of each optical member is increased, that is, each optical member is in the entire optical path of the light irradiated on the recording medium. The proportion occupied by the optical path formed therein will increase. As a result, the distance of light passing through the air becomes shorter, so that the influence of dust and dirt in the air can be reduced, so that the optical characteristics of the optical pickup can be further improved.

Since it is possible to impart optical characteristics necessary for irradiating the recording medium in each optical member, various optical members are separately provided in the optical path of the light emitted from the third optical member 49. This eliminates the necessity, and can reduce the number of parts and the assembly cost.

Further, the first optical member 41 and the third optical member 4
By equalizing the inclination angles of the respective inclined surfaces provided on the ninth and fourth optical members 53 for each optical member, a predetermined optical element is joined by combining a plurality of parallel flat plates formed in advance, and a predetermined angle is formed. Since the optical member can be easily manufactured with high precision by cutting out with the above, productivity of the optical member is greatly improved. In addition, since the angle is determined in advance, the optical axis can be easily adjusted, and the time and process required for axis alignment can be reduced.

The angle of inclination of each of the slopes provided on the first optical member 41, the third optical member 49, and the fourth optical member 53 with respect to incident light is in the range of 30 ° to 60 °, and is more preferably approximately. Preferably it is 45 °. It is preferable that the slopes provided on the respective optical members are provided at a predetermined distance from the relationship with the optical elements formed on the slopes. If a predetermined distance is not provided between the optical elements, there is a possibility that light transmitted slightly without being reflected will leak into the optical path of the emitted light beam, causing inconvenience such as becoming a stray light component. Will be higher.

Assuming that the predetermined distance is L, when the inclination angle of the slope is smaller than 30 °, for example, the first optical member 4
A difference 2L / √ (3) in the incident position occurs before the light is reflected by the first first slope 41a and enters the second slope 41b, and the thickness of the first optical member 41 is reduced by this difference. Too thick.

Further, when the inclination angle of the inclined surface is increased to 60 ° or more, the difference between the incident positions caused by setting the distance L is 30 degrees or less. Therefore, the volume of the first optical member 41 becomes too large.
Conversely, it is difficult to reduce the size of the optical pickup, which is not preferable.

Here, particularly when the inclination angle is approximately 45 °, the difference between the respective incident positions of the light reflected on the first inclined surface 41a of the first optical member 41 and incident on the second inclined surface 41b is determined. Since the first optical member 41 is almost eliminated, the size of the first optical member 41 can be reduced most efficiently, and the size of the optical pickup can be reduced efficiently.

Here, in particular, the inclination angles of the first slope 41a and the second slope 41b of the first optical member 41, and the slope angles of the first slope 49a and the second slope 49b of the third optical member 49 are described. The first slope 53a of the fourth optical member 53 and the second
Each optical member is formed such that the inclination angle of the inclined surface 53b is approximately 45 degrees.

With such a configuration, the optical axis direction of light entering each optical member can be substantially parallel to the optical axis direction of light emitted from each optical member. It is possible to simplify the method of positioning and assembling procedures when assembling the optical members, and to improve the productivity of the optical pickup. Further, in particular, by providing each optical member as a rectangular parallelepiped and providing each optical member such that the optical axis of the incoming / outgoing light with respect to the incoming / outgoing surface of the light of each optical member is substantially perpendicular, the amount of aberration generated in the incoming / outgoing light can be reduced. Since it can be reduced, good optical characteristics can be obtained.

In the present embodiment, the light emitted from the light source 2 and the light emitted from the light source 9 are configured to be incident on the same optical member. However, the optical members separately provided in the same package are provided. It is good also as a structure which is made to enter. With such a configuration, the optical member for the light emitted from the light source 2 and the optical member for the light emitted from the light source 9 can be separated from each other. Since only the elements need to be formed on the respective optical members, it is not necessary to separately form different types of optical elements on the same slope, and it is possible to eliminate factors that degrade the performance of the formed optical elements. Furthermore, for example, after the light emitted from the light source 2 is incident on the optical element for light emitted from the light source 9, the possibility of becoming a stray light component by being mixed into the optical path of the light emitted from the light source 2 again is reduced. Therefore, it is possible to provide an excellent optical pickup with less deterioration of optical characteristics.

The operation of the optical pickup having the above configuration will be described. When the recording medium is the high-density optical disk 18, recording or reproduction is performed using the light emitted from the light source 2. In this case, the light emitted from the light source 2 is first reflected by the reflection film 43 formed on the first slope 41a of the first optical member 41, and is reflected by the second slope 41b.
Is incident on the polarization splitting film 45 formed in the above. The polarized light separating film 45 reflects linearly polarized light emitted from the light source 2,
Since it has a function of transmitting light in a polarization direction orthogonal to that, the light incident from the light source 2 is reflected.

Thereafter, the light emitted from the first optical member 41 passes through the second optical member 47 and enters the third optical member 49. Then, the light passes through the filter 51 formed on the second slope 49 b of the third optical member 49, exits from the third optical member 49, and enters the ４ wavelength plate 52. This 1/4
The light incident on the wave plate 52 is converted from linearly polarized light into elliptically polarized light and emitted from the quarter wave plate 52.

After that, the light emitted from the light source 2 passes through the collimator lens 16 when it is provided with a collimator lens and is converted into substantially parallel light. It converges on the density optical disk 18.

The light reflected by the high-density optical disk 18 and returned returns to the quarter-wave plate 52 again. When this light is reflected by the high-density optical disk 18, the rotation direction of the elliptically polarized light is opposite to that at the time of incidence. Is converted into linearly polarized light substantially orthogonal to the polarization direction at the time of emission. That is, the light emitted as S-polarized light when emitted from the light source 2 enters the optical member as P-polarized light.

The light that has passed through the quarter-wave plate 52 enters the third optical member 49, almost passes through the filter 51 formed on the second slope 49b, and is emitted from the third optical member. The light passes through the second optical member 47 and enters the first optical member 41.

Then, the second slope 41 of the first optical member 41
b enters the polarization separation film 45. At this time, since the polarization direction of the incident light is orthogonal to that at the time of emission, the light is almost transmitted through the polarization separation film 45, is emitted from the first optical member 41, and is emitted from the fourth optical member 41. The light enters the member 53.

The light incident on the fourth optical member 53 is incident on the optical path dividing means 54 formed on the first slope 53a of the fourth optical member 53. By this optical path dividing means 54, approximately half of the incident light is transmitted and approximately half is reflected.

The light transmitted through the optical path dividing means 54 is
A light beam of a predetermined shape is formed in a light receiving portion formed at a predetermined position of the light receiving means 58 provided on the lower surface of the fourth optical member as it is, and is used for signal formation according to the purpose.

The light reflected by the optical path dividing means 54 is
A light beam having a predetermined shape is formed in a predetermined light receiving portion which is reflected by the reflection film 56 provided on the second inclined surface 53b of the fourth optical member 53 and is also received by the light receiving means 58. This will be used for signal formation.

When the recording medium is the low-density optical disk 19, recording or reproduction is performed using the light emitted from the light source 9. In this case, the light emitted from the light source 9 is first reflected by the reflection film 44 formed on the first slope 41a of the first optical member 41, and the polarization separation film 46 formed on the second slope 41b. Incident on. Since the polarization separating film 46 has a function of reflecting linearly polarized light emitted from the light source 9 and transmitting light in a polarization direction orthogonal to the polarized light, the light incident from the light source 9 is reflected.

Thereafter, the light emitted from the first optical member 41 enters the diffusion angle conversion means 48 formed on the end face of the second optical member 47. The light emitted from the light source 9 is converted into a diffusion angle by the diffusion angle conversion means 48, and the light that has been the diffused light becomes convergent light, is emitted from the second optical member 47, and enters the third optical member 49. I do.

The light incident on the third optical member 49 is incident on the multiple beam forming means 50 formed on the first inclined surface 49a, passes through the polarization splitting film 50a, and passes through the beam splitting section 50b.
When the light is reflected by the filter, the light is separated into one main beam and two side beams, and then enters the filter 51 formed on the second slope 49b. The filter 51 is formed so as to reflect the light emitted from the light source 9 and transmit the light emitted from the light source 2, so that the light incident on the filter 51 from the multiple beam forming means is substantially reflected and The light is emitted from the three optical members 49.

Thereafter, the light emitted from the light source 9 becomes 1/4.
The light enters the wave plate 52. The light incident on the quarter-wave plate 52 has its polarization direction changed from linearly polarized light to elliptically polarized light, and is emitted from the quarter-wave plate 52.

After that, the light emitted from the light source 9 passes through the collimator lens 16 when it is provided with a collimator lens and is converted into substantially parallel light. It converges on the density optical disk 18.

The light reflected by the low-density optical disk 19 and returned returns to the quarter-wave plate 52 again. When this light is reflected by the low-density optical disk 19, the rotation direction of the elliptically polarized light is opposite to that at the time of incidence. Is converted into linearly polarized light substantially orthogonal to the polarization direction at the time of emission. That is, the light emitted as S-polarized light when emitted from the light source 9 enters the optical member as P-polarized light.

The light having passed through the quarter-wave plate 52 is incident on the third optical member 49 and is almost reflected by the filter 51 formed on the second slope 49b.
The light enters the multiple beam forming means also received in 9a. In this case, since the polarization direction of the incident light is substantially orthogonal to the incoming light, the incident light is reflected by the polarization separation film 50a almost without entering the beam separation unit 50b, The light is emitted from the third optical member and is incident on the diffusion angle conversion means 48 formed on the second optical member 47.

The light incident as diffusion light by the diffusion angle conversion means 48 is converted into a divergent angle, becomes convergent light, passes through the second optical member 47, and enters the first optical member 41.

The second slope 41 of the first optical member 41
b enters the polarization separation film 46. At this time, since the polarization direction of the incident light is substantially orthogonal to that at the time of emission, the light almost passes through the polarization separation film 46 and is emitted from the first optical member 41,
The light enters the fourth optical member 53.

The light incident on the fourth optical member 53 is incident on the optical path dividing means 55 formed on the first slope 53a of the fourth optical member 53. By this optical path dividing means 54, approximately half of the incident light is transmitted and approximately half is reflected.

The light transmitted through the optical path splitting means 55 is
A light beam of a predetermined shape is formed in a light receiving portion formed at a predetermined position of the light receiving means 59 provided on the lower surface of the fourth optical member as it is, and is used for signal formation according to the purpose.

The light reflected by the optical path dividing means 55 is
A light beam having a predetermined shape is formed on a predetermined light receiving portion provided on the light receiving means 59 by being reflected by the reflection film 57 provided on the second inclined surface 53b of the fourth optical member 53, and a signal corresponding to the purpose is provided. It will be subjected to formation.

Even in the case where a plurality of light sources are arranged in the same package, the wavefront aberration generated in the light emitted from each light source often differs greatly as in the second embodiment. Although the distances between the light emitting points 2a and 9a of the light sources 2 and 9 and the collimating lens are optimized, the concept is the same as in the first embodiment, and the description is omitted here.

(Embodiment 4) Embodiment 4 of the present invention will be described below with reference to the drawings.

FIG. 10 is a sectional view of an integrated optical head according to the fourth embodiment of the present invention, and FIG. 11 is a detailed sectional view of an optical part according to the fourth embodiment of the present invention. In FIGS. 10 and 11, members having the same configuration as in the third embodiment are denoted by the same reference numerals.

In FIG. 10 and FIG.
Regarding 0, although there are slight differences in the size, shape, and the like of each of the components 70a, the sidewalls 70b, and the terminals 70c that are the constituent elements, the components 0 and 40c and the terminals 40c of the package 40 are different from each other. Since they have almost the same configuration, the description is omitted.

The light source mounting portion 71 on which the light sources 2 and 9 are mounted has substantially the same configuration as the light source mounting portion 42 of the third embodiment, and a description thereof will be omitted.

Reference numeral 72 denotes a first optical member.
Has a function of guiding the light emitted from the light source 2 and the light source 9 to a predetermined optical path and guiding the light reflected by the optical disk and returned to the predetermined optical path.

The first optical member 72 has a first slope 72a,
It has a second slope 72b and a third slope 72c,
In particular, it is preferable that the surface on which light is incident and the surface on which light is emitted are substantially parallel, and that light incident or emitted is incident on these surfaces substantially perpendicularly. By forming in this manner, generation of astigmatism or the like with respect to incident light can be suppressed, so that deterioration of optical characteristics of transmitted light can be prevented.

Further, the first slope 72a and the second slope 72
Various optical elements are formed in b and 72c.

Hereinafter, various optical elements existing in the first optical member 72 will be described. First, on the first slope 72a,
A reflection film 73 and a reflection film 74 are formed. Reflective film 7
Numeral 3 has a function of reflecting light emitted from the light source 2 in a predetermined direction, and the reflection film 74 has a function of reflecting light emitted from the light source 9 in a predetermined direction. .
The reflective film 73 and the reflective film 74 are formed by alternately providing a plurality of metal materials having high reflection, such as Ag, Au, and Cu, or a plurality of dielectric materials having different refractive indexes. Is preferred.

In this embodiment, the reflection film 73 and the reflection film 74 are provided separately, but may be formed as a single large reflection film on almost the entire first inclined surface 72a. In this case, the process of forming a reflective film using a mask can be omitted, and the number of masks for forming the reflective film can be reduced, so that productivity can be improved and manufacturing cost can be reduced. it can.

The polarization separation films 75 and 76 are formed on the second inclined surface 72b. Light emitted from the light source 9 and reflected by the reflection film 73 enters the polarization separation film 75, and light emitted from the light source 2 and reflected by the reflection film 73 enters the polarization separation film 75. . These polarization separation films 75 and 76 transmit light having a specific polarization direction,
It has a function of reflecting light having other polarization directions.

It is preferable that such polarization separating films 75 and 76 are formed by alternately providing a plurality of layers of a plurality of dielectric materials having different refractive indices because more accurate PS separation can be performed. In particular, here, it is formed so as to transmit the S-polarized light component emitted from the light source 2 and the light source 9 and reflect the P-polarized light component.

The polarization separating films 75 and 76 can guide the amount of light passing through to the recording medium without substantially reducing the amount thereof, so that the light use efficiency can be improved and the light source 2 and the light source 9 can be improved. Is preferable because a predetermined surface light amount can be obtained with a small output, and a long life of each light source can be realized.

In this embodiment, the polarization separation film 7 is used.
5 and 76 are provided separately, but may be formed as a single large reflective film on almost the entire upper portion of the second inclined surface 72b. In this case, the process of forming a polarization separation film using a mask can be omitted, and the number of masks for forming the polarization separation film can be reduced, so that productivity can be improved and manufacturing costs can be reduced. can do.

In the present embodiment, the polarization splitting film is used as the means for separating outgoing light and return light. However, these light splitting means use a separating means such as a half mirror according to the required surface light quantity. Is also good.

Next, another optical member provided on the second inclined surface 72b will be described. Reference numerals 77 and 78 denote holograms for monitor light. The hologram 77 has a function of reflecting and diffracting a part of the light emitted from the light source 2 and reflected by the reflection film 73 in a predetermined direction. The light reflected and diffracted by the hologram 77 is guided to a reflecting portion 79 provided on the upper surface of the first optical member 72, and thereafter enters a monitor light receiving portion provided on the light receiving means. Then, the power applied to the light source 2 is adjusted based on the electric signal from the monitor light receiving unit, and control is performed so that the amount of light emitted from the light source 2 always becomes an optimum value.

The hologram 78 has a function of reflecting and diffracting a part of the light emitted from the light source 9 and reflected by the reflection film 74 in a predetermined direction. This hologram 7
The light reflected and diffracted by 8 is guided to the reflection section 80 provided on the upper surface of the first optical member 72, and thereafter enters the monitor light receiving section provided on the light receiving means. Then, the power applied to the light source 9 is adjusted based on the electric signal from the monitor light receiving unit, and control is performed so that the amount of light emitted from the light source 9 always becomes an optimum value.

Further, reflection films 81 and 82 are provided on the portion of the second inclined surface 72b closest to the light source.

The reflecting films 81 and 82 have substantially the same structure as the reflecting films 57 and 58 formed on the second inclined surface 53b of the fourth optical member 53 shown in the third embodiment. Here, the description is omitted.

Finally, optical path dividing means 83 and 84 are formed on the third inclined surface 72c. This optical path dividing means has substantially the same configuration and function as the optical path dividing means 55 and 56 formed on the first slope 53a of the fourth optical member 53 shown in the third embodiment. Here, the description is omitted.

Next, it is preferable that the inside of the space surrounded by the package 70, that is, the space in which the light sources 2, 9 and the light receiving means are disposed is sealed. By adopting such a configuration, it is possible to prevent impurities such as dust and moisture from entering the inside of the package, so that it is possible to maintain the performance of the light sources 2 and 9 and the light receiving means and to reduce the amount of emitted light. Deterioration of optical characteristics can also be prevented.

For this reason, a shield member 85 is provided. The shield member 85 is provided on the side wall 70 of the package 70.
It is provided so as to close the opening 70d provided in the package 70b, and has a function of sealing the inside of the package 70. The sealed space is filled with an inert gas such as N ₂ gas, dry air, or Ar gas.
It is more preferable because it is possible to prevent the deterioration of the optical characteristics due to dew condensation on the surface of the light source and the like, and the deterioration of the characteristics due to oxidation of the light sources 2 and 9 and the light receiving means.

Here, as the material forming the shield member 85, it is preferable to use a material such as resin and glass which has good light transmission properties and does not reduce the light use efficiency.

Next, the second optical member 86 will be described.
The second optical member 86 is provided so as to cover the opening 70d provided in the side wall 70b of the package 70, and is joined to the side wall 70b of the package 70 with an ultraviolet curing resin, an epoxy resin, an adhesive glass, or the like. Have been.
The second optical member 86 includes a first substrate 86a and a second substrate 86b.
have. Hereinafter, these substrates will be sequentially described.

First, the first substrate 86a is formed of a material having good translucency such as glass or resin having a parallel plane shape, and is provided in an area where the light from the light source 9 passes on the end face on the shield member 85 side. Is formed with a diffusion angle conversion means 87. The divergence angle conversion means 87 has substantially the same configuration as the divergence angle conversion means 48 shown in the third embodiment, and a description thereof will be omitted.

Next, the second substrate 86b is provided with a first slope 86d.
And a plurality of beam forming means 88 having a polarization separation film 88a and a beam separation portion 88b are formed on the first slope 86d.
In e, a filter 89 is formed.

The structure of the second substrate 86b is basically the same as that of the third optical member 49 shown in the third embodiment. The first substrate 86b has a first inclined surface 86d, a second inclined surface 86e, and a second inclined surface 86e.
The polarization separation film 88a, the beam separation unit 88b, the multiple beam forming means 88, and the filter 89 are respectively a first slope 49a and a second slope 49 of the third optical member 49 of the third embodiment.
b, the polarization splitting film 50a, the beam splitting section 50b, the multiple beam forming means 50, and the filter 51, which have substantially the same configuration, and thus detailed description is omitted here.

The bonding between the first substrate 86a and the second substrate 86b and the bonding between the second optical member 86 and the side wall 70b are performed by a bonding material such as a photo-curing resin, an epoxy resin, or a bonding glass.

The light from the light source 2 and the light from the light source 9 are guided to substantially the same optical axis by the second optical member 86.

Thereafter, the light from the light source 9 is transmitted to the second optical member 86.
The optical path from the first optical member 7 to the filter 89 after being incident on the filter 89 after being reflected by the plurality of beam forming means 88.
2 is formed so as to travel in a direction substantially perpendicular to a plane including light traveling in the interior.

Numeral 90 denotes a 波長 wavelength plate, and １ ／ wavelength plate 52
Has a function of converting the polarization directions of both the light from the light source 2 transmitted through the filter 89 and the light from the light source 9 reflected by the filter 89 from linearly polarized light to elliptically polarized light.

The quarter-wave plate 90 may be a plate having a predetermined thickness as shown in this embodiment, or may be formed as a thin film.

Reference numerals 91 and 92 denote light receiving means. The light receiving means 91 receives light transmitted through the optical path dividing means 83 and light reflected by the optical path dividing means 83 and then reflected by the reflection film 81. The means 92 receives the light transmitted through the light path dividing means 84 and the light reflected by the reflection film 82 after being reflected by the light path dividing means 84.
A required number of various light receiving units are formed in required positions and at necessary positions for forming signals, monitor signals, tracking signals, and focusing signals.

As described above, by adopting a configuration in which light from a plurality of light sources having different oscillation wavelengths is made incident on an optical member on which a plurality of optical elements are formed and guided to a predetermined optical path, each of the conventional devices Since a plurality of optical elements and the like provided for each of the light sources can be integrated into one, the size of the entire optical pickup can be significantly reduced as compared with an optical pickup arranged in a distributed manner, and each light source can be reduced. This eliminates the need for positioning between optical elements, greatly improving productivity, and further minimizing the mounting error of each optical element, thereby realizing good optical characteristics. Since the loss of light due to the mounting error of each optical element can be suppressed to a minimum, an optical pickup with good light use efficiency can be realized.

Further, at least one of the light emitted from the light source 2 and the light emitted from the light source 9 is
The light is reflected a plurality of times and guided to a predetermined optical path, whereby the size of the entire package 70 can be reduced, and the optical path length after exiting the second optical member 86 can be shortened as compared with the case where the light is guided without reflection. Therefore, the size and thickness of the optical pickup can be reduced.

The light from the light source 2 and the light from the light source 9 are made incident on the optical members 72 and 86 on which a plurality of optical elements are formed and guided to a predetermined optical path. Both light can be accurately guided to each recording medium, and there is no need to form multiple optical systems corresponding to multiple light sources using different optical members, thus improving productivity by reducing the number of parts. In addition, it is possible to simplify the positioning of each component member.

Next, a plurality of slopes provided on each optical member will be described. First, a first slope 72a, second slopes 72b and 72c provided on a first optical member 72 are provided.
Are formed so as to have the same inclined angle and the same inclined surface in the same direction.

The first slope 86d and the second slope 86e provided on the second substrate 86b of the second optical member 86.
Are formed so as to have the same inclined angle and the same inclined surface in the same direction, and have a non-parallel relationship with the inclined surface of the first optical member 72.

As described above, since the inclination direction of the slope formed on the optical member is the same for each optical member, a plurality of plate members on which predetermined optical elements are formed in advance can be used. Since the optical member can be easily manufactured by combining and joining and cutting out at a predetermined angle, the productivity of the optical member can be improved. Further, since the angle can be determined in advance, the optical axis can be adjusted at the same time, and the time and process required for axis alignment can be reduced.

Also, since various optical elements can be arranged at positions where light is reflected on each slope, predetermined optical characteristics can be imparted when light entering each optical member is transmitted. .

In particular, when light from a plurality of light sources is guided to the same optical path as shown in the present embodiment, the slope formed in the first optical member 72 and the second optical member 86 should be at least two. The light provided from the light source 2 or the light source 9 is reflected by reflecting the light from at least one light source two or more times and passing through various optical members formed on the respective slopes. It is preferable because the optimization can be easily performed in the inside.

In particular, by making the inclination direction of the slope different for each optical member, the distance from the light source 2 or the light source 9 to the emission surface of the second optical member 86 can be increased. The distance from the recording medium 86 to the recording medium can be further reduced, and the size of the optical pickup can be reduced.

Furthermore, since the inclination direction of the slope is different for each optical member, the direction in which light is reflected is also different, so that the width of the optical member is smaller than when the light is guided in a fixed direction. Can be smaller. As a result, the width of the package 70 on which these optical members are provided can be reduced, and the size of the carriage (not shown) to which the package 70 is mounted can also be reduced.
The size of the drive device on which the pickup is mounted can be reduced.

By the way, in the optical axis direction of the light emitted from the second optical member 86, the thickness of each optical member becomes thicker than when the light is guided in only one direction, that is, when the recording medium is irradiated. The ratio of the light path formed in each optical member to the entire light path of the light is high.
As a result, the distance of light passing through the air becomes shorter, so that the influence of dust and dirt in the air can be reduced, so that the optical characteristics of the optical pickup can be further improved.

Also, since it is possible to impart optical characteristics necessary for irradiating the recording medium in each optical member, various optical members are separately provided in the optical path of the light emitted from the second optical member 86. This eliminates the necessity, and can reduce the number of parts and the assembly cost.

Further, by making the inclination angles of the slopes provided on the first optical member 72 and the second optical member 86 equal for each optical member, a plurality of parallel flat plates on which predetermined optical elements are formed in advance can be formed. Since the optical member can be easily manufactured with high accuracy by combining and joining and cutting out at a predetermined angle, the productivity of the optical member is greatly improved. In addition, since the angle is determined in advance, the optical axis can be easily adjusted, and the time and process required for axis alignment can be reduced.

In particular, the first slope 72 of the first optical member 72
a, by equalizing the inclination angles of the second inclined surface 72b and the third inclined surface 72c, a predetermined optical element can be easily joined by combining a plurality of parallel flat plates formed in advance and cutting out at a predetermined angle. Since the optical member 22 can be manufactured with high accuracy, the productivity of the optical member 22 is greatly improved. In addition, since the angle is determined in advance, the optical axis can be easily adjusted, and the time and process required for axis alignment can be reduced.

The inclination angle of each slope provided on the first optical member 72 and the second optical member 86 with respect to the incident light is in the range of 30 ° to 60 °, and more preferably approximately 45 °. Is preferred. It is preferable that the slopes provided on the respective optical members are provided at a predetermined distance from the relationship with the optical elements formed on the slopes. If you do not provide a predetermined distance between the optical elements,
Light transmitted slightly without being reflected is likely to leak into the optical path of the outgoing light flux, which may cause inconvenience such as becoming a stray light component.

Assuming that the predetermined distance is L, when the inclination angle of the slope is smaller than 30 °, for example, the first optical member 7
The incident position difference 2L / √ (3) is generated before the light is reflected by the second first inclined surface 72a and enters the second inclined surface 72b, and the thickness of the first optical member 72 is reduced by this difference. Too thick.

Further, when the inclination angle of the inclined surface is increased to 60 ° or more, the difference between the incident positions caused by taking the distance L occurs as in the case of 30 ° or less. Therefore, the volume of the first optical member 72 becomes too large by that amount,
Conversely, it is difficult to reduce the size of the optical pickup, which is not preferable.

Here, particularly when the inclination angle is approximately 45 °, for example, the difference between the incident positions of the light reflected on the first inclined surface 72a of the first optical member 72 and incident on the second inclined surface 72b. Is almost eliminated, so that the first optical member 72 can be miniaturized most efficiently, and thus the optical pickup can be miniaturized efficiently.

Here, in particular, the first optical member 72 is provided on the second substrate 86b of the second optical member 86, and the inclination angles of the first inclined surface 72a, the second inclined surface 72b, and the third inclined surface 72c. Each optical member is formed such that the inclination angles of the first inclined surface 86d and the second inclined surface 86e are both approximately 45 degrees.

With such a configuration, the optical axis direction of light entering each optical member can be substantially parallel to the optical axis direction of light emitted from each optical member. It is possible to simplify the method of positioning and assembling procedures when assembling the optical members, and to improve the productivity of the optical pickup. Further, in particular, by providing each optical member as a rectangular parallelepiped and providing each optical member such that the optical axis of the incoming / outgoing light with respect to the incoming / outgoing surface of the light of each optical member is substantially perpendicular, the amount of aberration generated in the incoming / outgoing light can be reduced. Since it can be reduced, good optical characteristics can be obtained.

In the present embodiment, the light emitted from the light source 2 and the light emitted from the light source 9 are configured to be incident on the same optical member. However, the optical members provided separately in the same package are provided. It is good also as a structure which is made to enter. With such a configuration, the optical member for the light emitted from the light source 2 and the optical member for the light emitted from the light source 9 can be separated from each other. Since only the elements need to be formed on the respective optical members, it is not necessary to separately form different types of optical elements on the same slope, and it is possible to eliminate factors that degrade the performance of the formed optical elements. Furthermore, for example, after the light emitted from the light source 2 is incident on the optical element for light emitted from the light source 9, the possibility of becoming a stray light component by being mixed into the optical path of the light emitted from the light source 2 again is reduced. Therefore, it is possible to provide an excellent optical pickup with less deterioration of optical characteristics.

The operation of the optical pickup having the above configuration will be described. When the recording medium is the high-density optical disk 18, recording or reproduction is performed using the light emitted from the light source 2. In this case, the light emitted from the light source 2 is first reflected by the reflection film 73 formed on the first slope 72 a of the first optical member 72, and the second slope 72 b
Is incident on the polarization splitting film 75 formed in the above. This polarized light separating film 75 reflects linearly polarized light emitted from the light source 2,
Since it has a function of transmitting light in a polarization direction orthogonal to that, the light incident from the light source 2 is reflected.

Thereafter, the light emitted from the first optical member 72 passes through the shield member 85, passes through the first substrate 86a of the second optical member 86, and then passes through the second substrate of the second optical member 86.
Filter 8 formed on second slope 86e of substrate 86b
9 and exits from the second optical member 86 and enters the quarter-wave plate 90. The light incident on the 波長 wavelength plate 90 is converted from linearly polarized light into elliptically polarized light and emitted from the 波長 wavelength plate 90.

After that, the light emitted from the light source 2 passes through the collimator lens 16 when it is provided with a collimator lens, and is converted into substantially parallel light. It converges on the density optical disk 18.

The light reflected by the high-density optical disk 18 and returned returns to the quarter-wave plate 90 again. When this light is reflected by the high-density optical disk 18, the rotation direction of the elliptically polarized light is opposite to that at the time of incidence. Is converted into linearly polarized light that is substantially orthogonal to the polarization direction of the outgoing light emitted from. That is, the light emitted as S-polarized light when emitted from the light source 2 enters the optical member as P-polarized light.

The light that has passed through the quarter-wave plate 90 enters the second optical member 86, and the second slope 86 of the second substrate 86b.
e, the light is almost transmitted through the filter 89, emitted from the second optical member 86, transmitted through the shield member 85, and incident on the first optical member 72.

Then, the second inclined surface 72 of the first optical member 72
b is incident on the polarization splitting film 75 formed at b. At this time, the polarization direction of the incident light is orthogonal to that at the time of emission, so that the light almost transmits through the polarization separation film 75 and the third slope 72 c of the first optical member 72.
The light enters the optical path splitting means 83 formed in the above. By this optical path dividing means 83, approximately half of the incident light is transmitted and approximately half is reflected.

The light transmitted through the optical path dividing means 83 is
A light beam of a predetermined shape is formed on a light receiving portion formed at a predetermined position of the light receiving means 91 provided below the first optical member 72 as it is, and is used for signal formation according to the purpose.

The light reflected by the optical path splitting means 83 is:
A light beam having a predetermined shape is formed in a predetermined light receiving portion which is reflected by the reflection film 81 provided on the second inclined surface 72b of the first optical member 72 and is also received by the light receiving means 91, according to the purpose. This will be used for signal formation.

When the recording medium is the low-density optical disk 19, recording or reproduction is performed using the light emitted from the light source 9. In this case, the light emitted from the light source 9 is first reflected by the reflection film 74 formed on the first slope 72a of the first optical member 72, and the polarization separation film 76 formed on the second slope 72b. Incident on. The polarization separating film 76 has a function of reflecting linearly polarized light emitted from the light source 9 and transmitting light in a polarization direction orthogonal to the polarized light, so that light incident from the light source 9 is reflected.

Thereafter, the light emitted from the first optical member 72 enters the diffusion angle conversion means 87 formed on the lower end surface of the first substrate 86a of the second optical member 86. The diffusion angle of the light emitted from the light source 9 is converted by the diffusion angle conversion means 87, and the light that has been the diffused light is converted into convergent light to form the second substrate 8.
6b, and the second substrate 86b of the second optical member 86
Beam forming means 8 formed on the first slope 86d
8, the light is transmitted through the polarization splitting film 88a, is split into one main beam and two side beams when being reflected by the beam splitter 88b, and is formed on the second inclined surface 86e. Incident on the filter 89. Since this filter 89 is formed so as to reflect the light emitted from the light source 9 and transmit the light emitted from the light source 2, most of the light incident on the filter 89 from the multiple beam forming means 88 is reflected. The light is emitted from the second optical member 86.

Thereafter, the light emitted from the light source 9 becomes 1/4.
The light enters the wave plate 90. The light incident on the 波長 wavelength plate 90 is converted from linearly polarized light into elliptically polarized light and emitted from the 波長 wavelength plate 90.

After that, the light emitted from the light source 9 passes through the collimator lens 16 when it is provided with a collimator lens and is converted into substantially parallel light. It converges on the density optical disk 18.

The light reflected by the low-density optical disk 19 and returned returns to the quarter-wave plate 90 again. When this light is reflected by the low-density optical disk 19, the rotation direction of the elliptically polarized light is opposite to that at the time of incidence. Is converted into linearly polarized light substantially orthogonal to the polarization direction of the emitted light. That is, the light emitted as S-polarized light when emitted from the light source 9 enters the optical member as P-polarized light.

The light that has passed through the 波長 wavelength plate 90 enters the second optical member 86, is almost reflected by the filter 89 formed on the second inclined surface 86e of the second substrate 86b, and Is incident on a plurality of beam forming means 88 provided on the inclined surface 86d. In this case, since the polarization direction of the incident light is substantially orthogonal to the outgoing light, the incident light is reflected by the polarization separation film 88a almost without entering the beam separation unit 88b, Second substrate 86
b, and enters the diffusion angle conversion means 87 formed on the first substrate 86a.

The light incident as divergent light by the divergence angle conversion means 87 has its divergence angle converted, becomes convergent light, is emitted from the second optical member 86, passes through the shield member 85, and The light enters the optical member 72.

Then, the second inclined surface 72 of the first optical member 72
b enters the polarization separation film 76. At this time, the direction of polarization of the incident light is substantially orthogonal to that at the time of emission, so that the light almost passes through the polarization separation film 76 and splits the optical path formed on the third inclined surface 72c. The light enters the means 84. By this optical path dividing means 84, approximately half of the incident light is transmitted and approximately half is reflected.

Then, the light transmitted through the optical path dividing means 84 is
A light beam of a predetermined shape is formed on a light receiving portion formed at a predetermined position of the light receiving means 92 provided below the fourth optical member as it is, and is used for signal formation according to the purpose.

The light reflected by the optical path dividing means 84 is
A light beam having a predetermined shape is formed on a predetermined light receiving portion provided on the light receiving means 92 by being reflected by the reflection film 82 provided on the second inclined surface 72b, and is used for signal formation according to the purpose. .

Even in the case where a plurality of light sources are arranged in the same package, the wavefront aberrations generated in the light emitted from the respective light sources often differ greatly as in the second embodiment. The distances between the light emitting points 2a and 9a of the light sources 2 and 9 and the collimating lens are optimized, however, the concept is as described in the first and second embodiments.
Therefore, the description is omitted here.

(Embodiment 5) FIG. 12 is a front view of an optical pickup module according to Embodiment 5 of the present invention. In FIG. 12, reference numeral 101 denotes a disk. In the present embodiment, the disk 101 is a high-density disk 18 such as a digital video disk (hereinafter abbreviated as DVD).
Alternatively, a low-density disk 19 such as a compact disk (hereinafter abbreviated as CD) is used. Here the high density disc 1
As 8, for example, two substrates having a recording layer are prepared,
A disk or the like having a configuration in which the two substrates are bonded to each other.

Reference numeral 102 denotes a spindle motor for rotating the disk 101, which also has a mechanism for clamping the disk 101. The spindle motor unit 102 includes a spindle motor for rotating the disk 101 and the disk 10
1 is formed from a turntable or the like for accurately positioning 1.

Reference numeral 103 denotes an optical pickup unit for recording or reproducing data on or from the disk 101. The optical unit has the structure shown in Embodiment 1 and operates the condenser lens 17 with respect to the disk 100. An actuator 108 is provided.

As the optical pickup section, those shown in Embodiment Modes 2 to 4 can be used.

Reference numeral 104 denotes a feed unit for moving the optical pickup unit 103 to the inner and outer circumferences of the disk 101.

Reference numeral 105 denotes a module base on which a spindle motor unit, an optical pickup unit, and a feed unit are mounted.

Numerals 106 and 107 are flexible substrates for supplying electric power to the spindle motor and the optical pickup unit.

The operation of the optical pickup module having the above configuration will be described. When an instruction to reproduce data existing at a predetermined position on the rotating disk 101 is sent from the CPU by the spindle motor unit 102, first, the feed unit 104 is pulled while the condenser lens 17 is retracted by the actuator 108. Is driven to irradiate the disk 101 with light from the light source 2 or 9, and the optical pickup unit 103 is moved to a track where predetermined data exists while confirming the position.

After moving to the predetermined position, the actuator 10 provided in the optical pickup unit 103
8, the focusing signal and the tracking signal are detected, and the position is finely adjusted. Then, the reproduction signal of a predetermined track is detected by the light receiving means provided in the optical pickup unit 103 to reproduce the signal. .

The flexible substrates 106 and 107 are used for supplying power to the pickup unit 103, transmitting and receiving signals, and supplying power to the spindle motor unit 102.

In the optical pickup module having such a configuration, since the optical pickup section having the configuration shown in the first to fourth embodiments is used, the size and thickness of the optical pickup module can be reduced. it can.

[0296]

As described above, the present invention relates to an optical pickup in which a light source, an optical member, and a light receiving means are provided in one package, and at least two of the optical blocks constituting the optical member. One has a plurality of slopes, and an optical element is provided on at least one of the slopes, so that a predetermined optical path length can be obtained while reducing the size of the optical member. Also, excellent optical characteristics can be maintained.

Further, since the plurality of inclined surfaces of the optical block have the same inclination direction, a plurality of plate members on which predetermined optical elements are formed in advance are joined and cut at a predetermined angle. Thus, the optical member can be easily manufactured, so that the productivity of the optical member can be improved. Further, since the angle can be determined in advance, the optical axis can be adjusted at the same time, and the time and process required for axis alignment can be reduced.

Also, since various optical elements can be arranged at positions where light is reflected on each slope, predetermined optical characteristics can be imparted when light entering each optical member passes therethrough. .

The inclination direction of the inclined surface of the optical block is different for each optical block.
Since the distance from the light source to the emission surface of the optical member can be increased, the distance from the optical member to the recording medium can be shortened, and the size of the optical pickup can be reduced.

Further, since the inclination direction of the slope is different for each optical member, the direction in which light is reflected is also different, so that the width of the optical member is smaller than when the light is guided in a fixed direction. Can be smaller. As a result, the width of the package on which these optical members are provided can be reduced, and the size of the carriage on which the package is mounted can be reduced. Therefore, the size of the drive device on which the pickup is mounted can be reduced.

Here, when the angle between the inclined surface and the optical axis of the incident light is within the range of 30 ° to 60 °, the optical member can be reduced in size and the generation of stray light can be suppressed. Therefore, it is possible to provide an optical pickup which is small and thin and has good optical characteristics.

In addition, since the angle between the inclined surface and the optical axis of the incident light is approximately 45 °, the optical member can be miniaturized most efficiently and the generation of stray light can be almost eliminated. Therefore, it is possible to provide a small and thin optical pickup having good optical characteristics.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration and an optical path of an optical pickup device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a light emitting point and a collimating lens in an infinite optical system according to the first embodiment of the present invention.

FIG. 3 is a graph showing the relationship between the wavefront aberration amount and L in Embodiment 1 of the present invention.
3 and L4

FIG. 4 is a diagram showing a relationship between a light emitting point and a condenser lens in the finite optical system according to the first embodiment of the present invention.

FIG. 5 is a sectional view of an integrated optical head according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a relationship between a light emitting point and a collimating lens in an infinite optical system according to a second embodiment of the present invention.

FIG. 7 is a diagram showing the relationship between the amount of wavefront aberration and L5 and L6 depending on whether or not the objective lens is shifted in Embodiment 2 of the present invention.

FIG. 8 is a sectional view of an integrated optical head according to a third embodiment of the present invention.

FIG. 9 is a detailed cross-sectional view of an optical part according to Embodiment 3 of the present invention.

FIG. 10 is a cross-sectional view of an integrated optical head according to a fourth embodiment of the present invention.

FIG. 11 is a detailed sectional view of an optical part according to a fourth embodiment of the present invention.

FIG. 12 is a front view of an optical pickup module according to Embodiment 5 of the present invention.

FIG. 13 is a diagram showing an optical system of a conventional optical pickup.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 First package 1a Substrate part 1b Side wall part 1c Terminal 1d Emission part 2 Light source 3 Light receiving element 5 First optical member 5a First inclined surface 5b Second inclined surface 6 Optical path dividing means 7 Reflecting means 8 Second package 8a Substrate Part 8b side wall part 8c terminal 8d emission part 9 light source 10 light receiving element 11 second optical member 11a first inclined surface 11b second inclined surface 12 optical path dividing means 13 reflecting means 14 1/4 wavelength plate 15 optical path dividing means 16 collimator lens 17 Condenser lens 18 High-density optical disk 19 Low-density optical disk 20 Package 20a Substrate 20b Side wall 20c Terminal 21 Light receiving element 22 Optical member 22a First slope 22b Second slope 22c Third slope 22d First substrate 22e Second substrate 23 Diffusion angle conversion hologram 24 Filter 25 Polarization separation film 26 1/4 wavelength 27 Diffusion angle converting means 28 Multiple beam forming means 29 Reflecting means 30 Reflecting means 31 Diffusion angle converting means 32 Signal forming means 33 Light receiving element 40 Package 40a Substrate 40b Side wall 40c Terminal 40d Opening 41 First optical member 41a First Slope 41b Second slope 42 Light source mounting part 42a Surface 43,44 Reflection film 45,46 Polarization separation film 47 Second optical member 48 Diffusion angle conversion means 49 Third optical member 49a First slope 49b Second slope 50 Multiple beam forming means 50a Polarization separation film 50b Beam separation unit 51 Filter 52 Quarter wave plate 53 Fourth optical member 53a First slope 53b Second slope 54,55 Optical path splitting means 56,57 Reflection film 58,59 Light reception Means 70 Package 70a Substrate 70b Sidewall 70c Terminal 70d Opening 71 Source mounting part 72 First optical member 72a First slope 72b Second slope 72c Third slope 73,74 Reflection film 75,76 Polarization separation film 77,78 Hologram 79,80 Reflection unit 81,82 Reflection film 83 , 84 Optical path dividing means 85 Shield member 86 Second optical member 86a First substrate 86b Second substrate 86d First inclined surface 86e Second inclined surface 87 Diffusion angle conversion means 88 Plural beam forming means 88a Polarization separation film 88b Beam separation unit 89 Filter 90 1/4 wavelength plate 91 Light receiving means 92 Light receiving means 101 Disk 102 Spindle motor section 103 Optical pickup section 104 Feed section 105 Module base 106, 107 Flexible board 108 Actuator

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Haruhiko Kono 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] 1. An optical member having a light source, at least two optical blocks for guiding light emitted from the light source to a predetermined optical path via an optical element, and an optical member guided through the optical member and reflected by a recording medium. An optical pickup comprising: a light source, the optical member, and the light receiving unit in a single package, wherein at least two of the optical blocks are plural. An optical pickup characterized in that an optical element is provided on at least one of the slopes. 2. The optical pickup according to claim 1, wherein the inclination directions of the plurality of inclined surfaces of the optical block are the same. 3. The optical pickup according to claim 1, wherein an inclination direction of the inclined surface of the optical block is different for each optical block. 4. The optical pickup according to claim 1, wherein an angle between the inclined surface and an optical axis of the incident light is in a range of 30 ° to 60 °. 5. The optical pickup according to claim 1, wherein an angle between the inclined surface and an optical axis of the incident light is approximately 45 °. 6. A light source comprising a first light source, a second light source, and a plurality of slopes, wherein the light emitted from the first light source and the light emitted from the second light source are converted into the plurality of slopes. An optical member having at least two optical blocks for guiding to a predetermined optical path via an optical element formed on the optical member, and guided from the optical member;
An optical pickup including light receiving means for receiving light reflected by a recording medium, wherein the first light source, the second light source, the optical member, and the light receiving means are formed in one package. An optical pickup characterized in that a slope direction of a slope of the optical block constituting the optical member is constant for each optical block. 7. A light source having a first light source, a second light source, and a plurality of slopes, wherein light emitted from the first light source is directed to a predetermined optical path via an optical element formed on the slope. A first optical member for guiding, a second optical member having a plurality of inclined surfaces, and guiding light emitted from the second light source to a predetermined optical path through an optical element formed on the inclined surface; A first optical member for receiving light guided from the first optical member and reflected by the recording medium;
And a second light receiving means for receiving light guided from the second optical member and reflected by the recording medium, wherein the first light source, the second light source, An optical pickup in which a first optical member, the second optical member, the first light receiving means, and the second light receiving means are provided in a single package, wherein the first optical member or An optical pickup characterized in that the inclination directions of the plurality of inclined surfaces of the second optical member are constant for each optical member. 8. The first optical member has at least two optical blocks having a plurality of inclined surfaces, and the second optical member has at least two optical blocks having a plurality of inclined surfaces. 8. The optical pickup according to claim 7, wherein the inclination direction of the slope is constant for each optical block.