JPH11102529A - Optical head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make more easily and accurately performable the arranging of a light source mounting part in a specified position by a constitution in which a projection formed on a base is brought into contact with a light source mounting part. SOLUTION: A projection 151 having rough cube shape is formed on a base 1a. By bringing a side 151a of the projection 151 into contact with a light source mounting part 150, the light source mounting part 150 are positioned. That is, the light source mounting part 150 is placed beforehand on surface 1f of the base 1a, and is pressed to the accurately figured side 151a of the projection 151 for joining through a joining member. An angle facing the projection 151 and the base 1a of the light source mounting part 150 is provided with an R, or cut off for preventing contacting to a non-orthogonal part formed by the surface 1f of the base 1a and the side 151a of the projection 151, or for placing along the non-orthogonal part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head for recording and reproducing information on an optical disk, and more particularly to an optical head for recording information on a CD or a CD.
Recording and reproduction of optical discs with different specifications such as disc substrate thickness and recording density, such as conventional optical discs such as D-ROM and high density optical discs such as digital video discs (DVD, DVD-ROM, DVD-RAM). The present invention relates to an optical head mounted on a simple optical pickup.

[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. 14 shows an optical system of a conventional optical pickup. In FIG. 14, 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 shown in FIG. 14 will be described below. First, the operation for a low-density optical disk will be described. In FIG. 14, the light source mounting unit 2
Light emitted from the light source 200 mounted on the light source 12 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. And collimator lens 2
The light beam 209 converted from the diffused light into the parallel light in 02 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. The light flux 209 incident on the low-density optical disc lens 204 is condensed and converged on the low-density optical disc 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. 14, the light emitted from the light source 300 mounted on the light source mounting portion 213 enters the prism 201 with a predetermined diffusion angle, and
Only the light beam 210 transmitted through the first collimator lens 20a
2 is incident. The light flux 211 converted from the diffused light into the parallel light by the collimator lens 202 enters the objective lens. Here, the objective lens is previously set in the objective lens holding unit 203.
Is switched so that the high-density optical disk lens 205 is arranged. The light beam 211 incident on the low-density optical disk objective lens 205 is condensed 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 optical head used in the above-mentioned conventional optical pickup, it is difficult to accurately mount a light source mounting portion on which a light source is mounted at a predetermined position. There is a problem that the light source mounting portion is inclined and the optical axis of the light emitted from the light source is shifted, so that predetermined optical characteristics cannot be satisfied.

The present invention solves the above-mentioned conventional problems, and provides a high-precision optical head capable of improving the mounting accuracy of the light source mounting portion to the substrate and preventing the light source mounting portion from being tilted. It is intended to be realized.

[0011]

In order to solve the above problems, a projection is provided on a substrate on which a light source mounting portion is mounted, and the projection and the light source mounting portion are provided in contact with each other. At least a part of the corner of the portion was not in contact with the protrusion.

[0012]

The invention according to claim 1 has a light source, a light source mounting portion for mounting the light source, and a projection,
Since the light source mounting portion includes a substrate on which the light source mounting portion is mounted, and the projection is in contact with the light source mounting portion, the positioning of the light source mounting portion can be performed easily and accurately.

According to a second aspect of the present invention, since the upper surface of the substrate and the side surface of the projection are not in contact with at least a part of the corner of the light source mounting portion facing the upper surface and the side surface, the light source mounting portion is formed. It is possible to prevent the light emitted from the light source from being deviated from the predetermined optical axis due to the inclination.

According to a third aspect of the present invention, the projection means is provided with a reflecting means for reflecting the backward emitted light emitted from the light source along a predetermined optical axis in a direction different from the optical axis. It is possible to prevent the emitted light from being mixed into the optical path of the forward emitted light to become stray light, and it is not necessary to provide the reflection means by a separate member.

According to a fourth aspect of the present invention, since the light-absorbing means for absorbing the rear-emitted light emitted from the light source along a predetermined optical axis is formed on the projection, the rear-emitted light is transmitted along the optical path of the front-emitted light. It is possible to prevent stray light from being mixed therein, and it is not necessary to provide the reflection means with a separate member.

According to a fifth aspect of the present invention, a first light source includes:
A second light source, a first light source mounting portion for mounting the first light source, a second light source mounting portion for mounting the second light source, and a protrusion, The first light source mounting portion and the second light source mounting portion
A substrate on which the light source mounting portion is mounted, and at least one of the first light source mounting portion and the second light source mounting portion and the protrusion are in contact with each other. The positioning of the plurality of light source mounting portions in the optical head equipped with the light source can be easily and accurately performed.

According to a sixth aspect of the present invention, there is provided a semiconductor device, comprising:
Since at least a part of the corners of the light source mounting portion and the second light source mounting portion are not in contact with each other, in the optical head equipped with the plurality of light sources, the plurality of light source mounting portions are inclined,
It is possible to prevent light emitted from each mounted light source from being shifted from a predetermined optical axis.

According to a seventh aspect of the present invention, at least one of the first light source and the second light source is disposed so as to face the projection, and a surface facing the first light source and the second light source. By providing the reflecting means or the light absorbing means to the optical head, it is possible to prevent the rear emission light emitted from each light source from becoming stray light in the optical head having a plurality of light sources mounted thereon.

According to the present invention, the first light source mounting portion and the second light source mounting portion are made of the same member.
A plurality of light sources can be positioned at one time.

According to a ninth aspect of the present invention, the projection is divided into a first projection contacting the first light source mounting portion and a second projection contacting the second light source mounting portion. With this arrangement, the positional accuracy of each light source mounting portion can be improved.

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

FIG. 1 shows the configuration of an optical pickup according to the first embodiment of the present invention and the path of light from the light emitting point to the disk and guided to the light receiving means, that is, the optical path. In FIG. 1, a dotted line indicates an optical path when reproducing a conventional optical disk, and a solid line indicates an optical path when reproducing a high-density optical disk. In FIG. 1, 1
Is a first package, and the first package 1 has a substrate portion 1a 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 those members. The substrate portion 1a and the side wall portion 1b may be formed integrally or separately. When formed integrally, the assembly process can be simplified, and productivity can be improved. The material for forming the first package 1 is metal,
It is preferable to use a material such as a ceramic because heat generated by 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 of a pin type or a print type. Here, especially the pin type terminal 1c
Will be 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. In order to satisfy such requirements, it is preferable to use a hermetic seal or the like that can simultaneously perform both insulation and sealing. 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 light source 2 which is monochromatic and has good coherence, directivity, and light condensing properties, since a beam spot having an appropriate shape can be formed relatively easily, and generation of 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 them, AlGaAs is a preferable material because crystal growth is easy among compound materials, and therefore, semiconductor laser can be easily manufactured. Therefore, the yield is high 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.

Of these, 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 energy consumption can be suppressed to a minimum while securing sufficient light quantity necessary for reproduction. Further, the amount of heat emitted from the light source 2 can be suppressed, which is preferable. In the case of recording and reproduction, large energy is required to change the state of the recording layer at the time of recording, so that an output of at least 20 (mW) 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.

Next, the light source mounting section 150 on which the light source 2 is mounted will be described. The light source mounting portion 150 has a rectangular parallelepiped shape or a plate shape, and the light source 2 is attached to an upper surface or a side surface thereof. This light source mounting unit 150
The light source 2 is provided on the substrate portion 1a or the side wall portion 1b, and has a function of mounting the light source 2 and releasing heat generated by the light source 2. In consideration of heat conduction, etc., in joining the light source mounting portion 150 and the light source 2, solder such as Au-Sn is plated on the upper surface of the light source mounting portion 150 in advance, and a method of soldering at a high temperature or an Au- Sn, Sn-Ag, Sn-Sb,
It is preferable to use a method in which a foil (thickness of several μm to several tens of μm) such as Sn-Pb-In is pressure-bonded at a high temperature. Light source 2
If it is not mounted substantially parallel to the mounting surface of the light source mounting unit 150, it may cause aberrations in the optical system, decrease the coupling efficiency, and the like. Therefore, at the time of joining, it is preferable that the light source 2 be mounted on the light source mounting portion 150 at a predetermined position at a predetermined height and substantially parallel to the mounting surface.

Further, the light source 2 is provided on the upper surface of the light source mounting portion 150.
An electrode surface is provided so as to be in electrical contact with the lower surface of. This electrode surface is used to supply power to the light source 2, and the metal film constituting the electrode surface is made of A in consideration of conductivity and corrosion resistance.
It is preferable to use a thin film of u.

The light source mounting portion 150 has a high thermal conductivity due to problems such as heat generated from the light source 2 and attachment to the light source 2.
In addition, the coefficient of linear expansion is that of the light source 2 (about 6.5 × 10 ⁻⁶ /
C) are preferred. Specifically, the coefficient of linear expansion is 3
A substance having a thermal conductivity of 100 W / mK or more at 〜１０10 × 10 ⁻⁶ / ° C., such as AlN, SiC, T-cBN, Cu
/ W, Cu / Mo, Si, and the like, and particularly, when a high output light source 2 is used, and when the thermal conductivity must be extremely large, it is preferable to use a diamond or the like. When the linear expansion coefficients of the light source 2 and the light source mounting unit 150 are set to be the same or close to each other, the occurrence of distortion between the light source 2 and the light source mounting unit 150 can be suppressed. It is possible to prevent inconveniences such as detachment of the mounting portion 150 from the mounting portion 150 and cracking of the light source 2. However, if it is out of this range, the light source 2 and the light source
Therefore, there is a high possibility that a large distortion is generated between the light sources 2 and the light source 2 and the light source mounting portion 150 are detached from each other or the light source 2 is cracked. Further, by setting the thermal conductivity of the light source mounting portion 150 as large as possible, the heat generated in the light source 2 can be efficiently released to the outside. However, when the thermal conductivity is equal to or less than this limit, the heat generated by the light source 2 is difficult to escape to the outside, so the temperature of the light source 2 rises, and the wavelength of the light emitted from the light source 2 shifts, The convergence position of the light on the recording medium is slightly different, so that many noise components are mixed in the reproduced signal, or the output of the light source 2 is reduced, so that the recording / reproducing operation on the recording medium cannot be performed normally. Or light source 2
Of the light source 2 is likely to be shortened, or in the worst case, the light source 2 may be broken. In the present embodiment, AlN which is very excellent in both of these two characteristics is used. Further, it is preferable to form a thin film on the upper surface of the light source mounting portion 150 in the order of Ti, Pt, and Au from the light source mounting portion 150 toward the light source 2 in order to improve the bonding property with the light source 2. When Si is used as the material of the light source mounting portion 150, it is preferable to form an insulating layer such as an Al ₂ O ₃ film or a surface oxide film on the surface of the member before the Ti layer.

Next, the arrangement of the light source mounting section 150 on the substrate section 1a will be described. FIG. 15 is an enlarged view around the light source according to the first embodiment of the present invention.

A substantially rectangular projection 15 is provided on the substrate 1a.
1 is formed. Side portion 151 of this projection 151
By contacting a with the side surface portion 150a of the light source mounting portion 150, the mounting position of the light source mounting portion 150 can be determined. That is, the light source mounting portion 150 is placed on the front surface 1f of the substrate portion 1a in advance, and the light source mounting portion 150 is bonded to the side surface 151a of the protrusion 151 on which the surface is accurately exposed by a bonding material. .

With such a configuration, the light source mounting portion 150 on which the light source 2 is mounted can be more easily and accurately arranged at a predetermined position. Less deterioration of optical characteristics due to misalignment of
A high-performance optical head can be obtained.

Here, as a joining material used for joining the light source mounting portion 150 and the substrate portion 1a, it is required to use a metallic joining material such as solder or a photo-curing resin which is cured by ultraviolet light or visible light. It is preferable because it has a bonding strength not less than the value. In particular, when a metallic bonding material is used, the surface 1f of the substrate 1a, the side surface 151a of the protrusion 151, the light source mounting portion 1
It is preferable that the bottom surface 150b and the side surface 150a of the 50 be treated in advance to improve the bonding property, such as providing metal plating.

At this time, the bottom surface 15 of the light source
It is preferable that a corner formed by Ob and the side surface 150a in contact with the protrusion 151 has a predetermined radius or is cut off.

This will be described with reference to FIG.
FIG. 4 is an enlarged view around a light source according to an embodiment other than the present invention. As shown in FIG. 16, the surface 1 f of the substrate 1 a and the side surface 151 a of the projection 151 are often not exactly orthogonal, and in this case, when the light source mounting portion 150 is pressed against the projection 151, As shown, the light source mounting portion 150 is inclined, and the optical axis of light emitted from the light source 2 mounted on the light source mounting portion 150 is deviated from a predetermined position, so that light is projected on a predetermined track of the recording medium. Will not be irradiated. Therefore, accurate recording or reproduction cannot be performed.

Therefore, in the present embodiment, as shown in FIG. 15, R is added to the corner of the light source mounting portion 150 facing the projection 151 and the substrate 1a (solid line in the drawing) or cut off (in the drawing). (Dotted line portion), so that it does not touch the non-orthogonal portion formed by the surface 1f of the substrate portion 1a and the side surface 150a of the protruding portion 151, or extends along the non-orthogonal portion.

With such a structure, the substrate 1
When the front surface 1 f of the “a” is not orthogonal to the side surface 150 a of the projection 151, the light source mounting portion 150 can be joined to the substrate portion 1 a in a correct posture, and the light source mounting portion 150 is mounted on the light source mounting portion 150. An optical head having good recording / reproducing characteristics in which the optical axis of the light emitted from the light source 2 does not deviate from the predetermined optical axis can be obtained.

Further, the light source 2 mounted on the light source mounting portion 150
However, it is preferable that the projection 151 is formed so as to face the projection 151, that is, the projection 151 is formed in the extending direction of the rear emission light 2h of the light source 2. This will be described below.

As described above, the projection 151 is provided on the light source mounting portion 15.
Since the positioning of 0 is performed accurately, any surface may be in contact with the light source mounting portion 150 as long as it is originally in contact with the light source mounting portion 150.
However, it is necessary to take measures to prevent the backward emitted light 2h from the light source 2 from entering the light receiving element or the optical member and becoming stray light. In the present embodiment, this measure is applied to the projection 151. This will be described below.

In this case, the upper surface 151c of the projection 151
With respect to the end face 2i where the light emitting point 2g of the light source 2 exists.
It is provided at an angle. A film such as a metal or a dielectric having a high reflectivity is formed on the entire surface or a part of the upper surface 151c so that the rear emission light 2h emitted from the light emitting point 2g is non-perpendicularly reflected on the upper surface 151c. Is configured. At this time, the upper surface 15 of the protrusion 151
It is preferable that the inclination angle of 1c with respect to end surface 2i is set according to the diffusion angle of the light emitted from light source 2.

With such a configuration, both the backward emitted light 2h emitted from the light source 2 can be favorably reflected in a predetermined direction, and the backward emitted light 2h is reflected inside the first package 1. It is preferable because it is possible to prevent the light from being scattered and entering the optical member or the light receiving means as stray light.

Although the upper surface 151c of the projection 151 is formed to have a high reflectance, the light absorption may be increased instead of increasing the reflectance. As a configuration for increasing the light absorption coefficient, it is conceivable to provide a light absorbing film on the entire surface or a part of the upper surface 151c. As the light absorbing film, translucent glass or resin material, Si film, Ti film, or Si film
The film + Ti film is often used with a predetermined thickness.

Further, the thickness of the light absorbing film is preferably changed according to the wavelength of the incident light. In this way, even when light sources having different wavelengths are used, light from each light source can be reliably absorbed.

In the configuration using the light absorbing film, much of the energy of the absorbed light is converted into heat.
The material of the reflective member on which the light absorbing film is formed has good heat dissipation,
It is preferable to use a material having high thermal conductivity. By using such a material, it is possible to suppress the occurrence of inconvenience, such as a change in the composition of the light absorbing film due to a high temperature of the reflective member and a failure to perform a predetermined light absorbing action.

With this configuration, the light from the light emitting point 2g of the light source 2 is absorbed without being substantially reflected by the upper surface 151c, and the light from the light emitting point 2g is incident on the optical member. Almost no stray light,
An optical pickup with good signal characteristics can be realized.

In the case of reflecting light, the end face 2i of the light source 2 is used.
The upper surface 151c of the projection 151 inclined with respect to
In this case, it is not necessary to incline.

The first portion 1d of the first package 1
The optical member 5 is joined. This first optical member 5
It has a function of guiding light emitted from the light source 2 and reflected by the recording medium to a predetermined position of the light receiving element 3. Here, a configuration in a case where the first optical member 5 has a plurality of slopes and guides return light by using optical elements formed on each slope will be described.

The first optical member 5 has a first slope 5a and a second slope 5b formed therein. 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 a reflecting means 7 for guiding the incident light to the light receiving element 3 on the second slope 5b. Are formed. Further, particularly when a high-density optical disk is rewritable, it is necessary to irradiate the optical disk with very high energy, and thus it is necessary to guide the light emitted from the light source 2 onto the optical disk as efficiently as possible. In consideration of this, the optical path dividing means 6 is formed of a polarization separation film and
It is preferable to use in combination with the four-wavelength plate 4 because the light use efficiency is improved and recording or reproduction can be performed using a plurality of types of optical disks. Further, since the amount of light emitted from the light source 2 can be suppressed, the life of the light source 2 can be prolonged, and the reliability of the optical disk device can be improved, which is preferable.

The quarter-wave plate 4 has the 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 converted to the elliptically polarized light. Is converted into linearly polarized light orthogonal to the incident polarization direction.

It is preferable that an optical element corresponding to a 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. In consideration of the fact 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. Can be used more effectively.
This is a preferable configuration because the size and thickness of the 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. Furthermore, the first optical member 5 is mounted so that its upper and lower surfaces are exactly 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. In particular, 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. In addition, among these optical glasses, BK-7 is low in cost, and is therefore most suitable as the material of the first optical member 5.

The first optical member 5 may be formed by joining a plurality of dice-shaped prisms in which optical elements are previously formed 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 this embodiment, the first package 1 is directly connected to the emission section 1d provided on the side wall 1b of the first package 1.
Although the optical member 5 is bonded, the first package 1 and the first optical member 5 may be provided separately. Since the distance between the light source 2 and the first optical member 5 which becomes a problem when there is a variation in the height of the package 1 can be more accurately adjusted by providing the first optical member, the first optical member can be adjusted. 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 portions 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 these, 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 9 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.

However, the thermal conductivity of the material forming the second package 8 is preferably equal to or smaller than the thermal conductivity of the material forming the first package 1.
This is because the light source 2 for a high-density optical disk often has the same or higher output than the light source 9 for a low-density optical disk,
Therefore, the amount of heat emitted from the light source 2 is equal to or greater than the amount of heat emitted from the light source 9. If the heat radiation amount between the light source 2 and the light source 9 is different and the heat conduction amount of the portion that holds the light source and emits heat is the same, the light source 2 becomes higher in temperature than the light source 9. This is because the oscillation wavelength shifts, so that recording and reproduction on a high-density optical disc cannot be performed accurately, an electric circuit system may malfunction, and various inconveniences may occur.

By making the thermal conductivity of the material forming the second package 8 equal to or smaller than the thermal conductivity of the material forming the first package 1, the light source 2 becomes 9, the oscillation wavelength of the light source 2 shifts, making it impossible to accurately perform recording / reproducing on a high-density optical disc, causing malfunction of an electric circuit system, Various inconveniences can be prevented from occurring.

It is preferable that the contact areas of the first package 1 and the second package 8 with the carriage (not shown) be different. By making the contact area different, the larger area can emit more heat per unit time, so it is possible to effectively eliminate the difference in the amount of generated heat that can not be absorbed by the difference in thermal conductivity of each package. it can. Here, especially the first package 1
Are increased in contact area with the carriage.

When the oscillation wavelength of the light source 9 is 800 nm or less, 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.

Next, the light source mounting section 152 on which the light source 9 is mounted will be described. The light source mounting portion 152 has a rectangular parallelepiped shape or a plate shape, and has a light source 9 on its upper surface or side surface.
Is attached. The light source mounting portion 152 is provided on the substrate portion 8a or the side wall portion 8b, and has a function of mounting the light source 9 and releasing heat generated by the light source 9. When heat conduction and the like are taken into consideration in joining the light source mounting portion 152 and the light source 9, similarly to the light source mounting portion 152,
Due to the heat generated in the light source and the problem of attachment to the substrate portion 8a, the thermal conductivity is high and the linear expansion coefficient is
It is preferable to use a material close to. However, since the amount of heat generated from the light source 9 is not so large as compared with that from the light source 2, the requirements for these characteristic values are not so strict as compared with the light source mounting portion 150. Therefore, the light source mounting section 152 has a linear expansion coefficient of that of the light source 9 (about 6.5).
(× 10 ⁻⁶ / ° C.), and considering the output ratio of the light source 2 to the light source 9, it is preferable to use a material whose thermal conductivity is 1/5 or more of that of the light source mounting portion 150. Specifically, it is preferable to use a substance having a linear expansion coefficient of 3 to 10 × 10 ⁻⁶ / ° C. and a thermal conductivity of 20 W / mK or more. For example, as such a material, the light source mounting portion 150
Mo, Cu, Fe, FeN
There are an iCo alloy, a FeNi alloy, and the like. Here, the light source mounting portion 152 is formed of a material such as Cu or Mo which is very inexpensive compared to AlN in which the light source mounting portion 150 is formed, and has relatively excellent characteristics. did.

The area of the light source mounting section 152 in contact with the substrate section 8a or the side wall section 8b is smaller than that of the light source mounting section 150, and the contact area with the substrate is smaller than that of the light source mounting section 150. It is desirable to do. With such a configuration, heat generated in the light source 2, which generally generates a larger amount of heat than the light source 9, can be transmitted to the substrate particularly well. Therefore, even when a semiconductor laser having a low resistance to high temperatures is used, the temperature during use of the light source 2 can be prevented from becoming significantly higher than that of the light source 9, and as a result, the life of the light source 2 is reduced. It is no longer shorter than the life of the optical pickup, so that the life of the optical pickup can be relatively prolonged and the reliability can be improved.

Next, the arrangement of the light source mounting section 152 on the substrate section 8a is substantially the same as the arrangement of the light source mounting section 150 on the substrate section 1a as shown in FIG.
The same applies to the point that the light source 9 mounted on 52 is formed so as to face the protruding portion 153, and the description is omitted here.

However, the light source 2 and the light source 9 used in the present embodiment have different oscillation wavelengths in order to correspond to different recording media, and the light source 2 having a wavelength between 630 and 660 nm is used. 770 as 9
To 800 nm, the differences caused by this will be described.

In general, in the case of a metal or dielectric material used to reflect light, the ratio of reflected light to the incident light (reflectance) or the ratio of absorbed light (absorbance) is determined by the ratio of the incident light. It often changes depending on the wavelength of the incoming light, that is, there is a wavelength dependency of the reflectance. Therefore, when both the light from the light source 2 and the light from the light source 9 are reflected by the reflecting member having the same configuration, the ratio of the light from the light source 2 and the light from the light source 9 is different, resulting in an increase in scattering and the like. The inconvenience may occur.

Therefore, in the present embodiment, the protrusion 1
It is preferable that the material of the reflection film or the light absorption film formed on the upper surface 151c of the 51 is made different. That is, a reflection film is formed on the upper surface 151c with a material having a large reflectance (absorbance) with respect to the wavelength of the light emitted from the light source 2, and a large reflectance (with respect to the wavelength of the light emitted from the light source 9). Absorbance)
A reflective film is formed on the upper surface 153c with a material having the following.

By adopting such a configuration, the backward emission light emitted from the light source 2 and the light source 9 can both be reflected well in a predetermined direction (can be absorbed well), and the respective packages This is preferable because it is possible to prevent light from being reflected and scattered inside the optical member and from entering the optical member and the light receiving means as stray light.

In the configuration using the light absorbing film, much of the energy of the absorbed light is converted into heat.
The material of the reflective member on which the light absorbing film is formed has good heat dissipation,
It is preferable to use a material having high thermal conductivity. By using such a material, it is possible to suppress the occurrence of inconvenience, such as a change in the composition of the light absorbing film due to a high temperature of the reflective member and a failure to perform a predetermined light absorbing action.

Further, since the light source mounting portion 152 is formed smaller than the light source mounting portion 150 of the first package 1, this will be described.

The light source 2 mounted on the light source mounting section 150 is used for recording or reproduction of a high-density optical disk, and the light source 9 mounted on the light source mounting section 152 is used for reproducing a low-density optical disk. It is provided.

For recording on an optical disk, it is common to use a light source with a very high output (normal output of 20 w or more). On the other hand, for reproduction on an optical disk, a light source with a very high output is not required. Usually, a light source of several mw class is generally used.

Therefore, the required heat radiation level is required between the light source mounting portion 150 on which the light source 2 which may be used for recording is mounted and the light source mounting portion 152 on which the light source 9 used for reproduction is mounted. There is a difference, and as one method for coping with this difference, it is effective to make the shape itself different.

That is, the size of the light source mounting portion 150 is made larger than the size of the light source mounting portion 152, so that the heat capacity of the light source mounting portion 150 is increased, and the heat generated by the light source 2 is efficiently emitted from the light source. It was configured to be transmitted to the mounting section 150.

With such a configuration, the light source 2
Can be emitted to the light source mounting portion 150 by conduction, and furthermore, the heat radiation from the surface of the light source mounting portion 152 and the heat radiation from the light source mounting portion 150 to the substrate portion 1a or the side wall portion 1b can be further reduced. Since it can be used in a large ratio, heat from the light source 2 having a large amount of heat can be emitted very efficiently.

At this time, it is preferable that the amount of heat conducted by the light source mounting portion 150 is larger than the amount of heat conducted by the light source mounting portion 152. With such a configuration, heat from the light source 2 having a higher output can be more efficiently released to the outside through the light source mounting portion 150.

As a result, heat is accumulated around the light source 2 and a shift in the wavelength of light emitted from the light source 2 due to the high temperature of the light source 2 can be suppressed.
Further, since the temperature rise of the light source 2 can be suppressed efficiently, the light source 2 can be prevented from being deteriorated or destroyed by heat, and thus the reliability of the optical pickup can be improved.

In the present embodiment, the light source placement section is differentiated by making the shape of the light source placement section different. However, the difference in the volume of the light source placement section is the least This is effective because it works effectively.

By making the surface area of the light source mounting part 150 larger than the surface area of the light source mounting part 152, the amount of radiant heat from the surface of the light source mounting part 150 can be further increased. By increasing the amount of radiant heat per unit time from the light source mounting unit 150 to the amount of radiant heat from the light source mounting unit 152 per unit time, heat can be efficiently radiated to the outside from the light source mounting unit 150 even by radiation. And the thermal load on the light source 2 can be reduced.

Although two light source packages are used in this embodiment, any number of light source packages may be used as long as two or more light source packages are used. In this case, it is preferable to make the physical properties of the light source mounting portion different according to the output of the light source mounted on each light source package.

As described above, the physical properties (for example, heat capacity, size, volume, surface area, etc.) of the light source mounting portion 150 on which the light source 2 is mounted are determined by the light source mounting portion 1 on which the light source 9 is mounted.
By making the physical property of the light source 2 different from the physical property of the light source 52, the heat generated from the light source 2 which is likely to be higher in temperature with high output can be efficiently released. Oscillation wavelength shifts or light source 2
Can be prevented from being destroyed by heat.

Further, the temperatures of the light source 2 and the light source 9 during operation can be made substantially the same, that is, since only one of them does not operate at a significantly high temperature, The life of the optical pickup does not largely differ, and thus a highly reliable optical pickup can be provided without the life of the optical pickup being extremely different.

The configuration of the second optical member 11 is substantially the first
It is the same as the 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 2 and the light receiving element 3 can be maintained, and optical characteristics of emitted light can be maintained. Deterioration of characteristics can also be prevented. Further, in a space enclosed by the first package 1 and the first optical member 5, an inert gas such as N ₂ gas, dry air or Ar gas is sealed.
Condensation on the surface of the first optical member 5 and the like in contact with the inside of the package 1 degrades optical characteristics, and prevents deterioration of characteristics due to oxidation of the light source 2 and the light receiving element 3. Therefore, it is more preferable.

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 15, 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.

It is preferable to use a reflecting means having a wavelength selecting function as the optical path dividing means 15 having the above-mentioned properties. 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 9 can be used at an output much lower than the maximum output, the life of the light source 9 can be prolonged, and the reliability of the optical pickup device can be improved.

Instead of using the collimating lens 16, the first optical member 5, the second optical member 11 and the like 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.

Reference numeral 18 denotes a high-density optical disk attached to a spindle motor (not shown). The high-density optical disk 18 is often formed by laminating two disk substrates each having a thickness of about 0.6 mm. . The light beam 2b emitted from the light emitting point 2a of the light source 2 is
The light passes through the optical path splitting means 6 formed on the first inclined surface 5a, is changed in the polarization direction from linearly polarized light to circularly polarized light by the quarter-wave plate 4, and is incident on the optical path splitting means 15. After being substantially transmitted through the optical path splitting means 15, the light is converted into a light beam 2c by a collimator lens 16 and condensed by a condenser lens 17 as a light beam 2d. 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.
Next, the optical path of the forward light for reproducing No. 9 will be described. Here, the thickness of the low-density optical disk 19 is 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 splitting means 15, the light is converted into a light flux 9 c by the collimator lens 16 and condensed on the low-density optical disc 19 like a light flux 2 d by the condenser lens 17.

At this time, the focal length L2 of the condenser lens 17 when reproducing the low-density optical disk 19 is set to be longer than the focal length L1 of the condenser lens 17 when reproducing the high-density optical disk 18. I have. The difference between the focal lengths is set to 1.0 mm or less, and preferably 0.6 mm or less. When each of a plurality of different types of discs is reproduced, it is almost necessary to largely drive the actuator holding the condenser lens 17. Disappears. 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, the light from the plurality of light sources is focused on different positions on the recording medium, so that recording media having different substrate thicknesses can be reproduced by the same optical pickup device. Become. That is, a low-density optical disk 19 such as a CD-ROM having a thickness of 1.2 mm and a high-density optical disk 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 are the same optical pickup. It is possible to record and reproduce on the device.

The focal length L1 and the focal length 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 path, that is, the return path, until the reflected light from the high-density optical disk 18 and the low-density optical disk 19 is detected will be described.

First, the case of reproducing the high-density optical disk 18 will be described. The reflected light from the high-density optical disk 18 follows the substantially same optical path as the outward path, and
And is converted from circularly polarized light into linearly polarized light orthogonal to the first polarization direction by the 波長 wavelength plate 4.
Incident on the optical path dividing means 6 formed on the inclined surface 5a. 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 low density optical disc 19 is reproduced will be described. The reflected light from the low-density optical disk 19 follows the same optical path as the outward path, and
5, the light is converted from circularly polarized light into linearly polarized light orthogonal to the first polarization direction by the quarter-wave plate 14, and the second optical member 1
The light enters the optical path splitting means 12 formed on the first slope 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. Therefore, the reflection means 1
The light reflected by 3 is focused on the light receiving element 10 while forming a focus error signal, and detects a signal corresponding to data recorded on the low-density optical disc 19, a track error signal, and a focus error signal.

When a plurality of light sources are arranged at different positions as described above, 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 a relationship between a light emitting point and a collimating lens in the infinite optical system according to the first embodiment of the present invention. 2, L3 indicates the distance from the collimator lens 16 to the light emitting point 2a, and L4 indicates the distance from the collimator lens 16 to the light emitting point 9a.
Further, FIG. 3 shows the relationship between L3 and L4 and the amount of wavefront aberration generated in light from the light emitting point depending on whether or not the objective lens is shifted according to the first embodiment of the present invention. That is, when the ratio of L3 and 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 by the condenser lens 17 (thick line) and when there is no shift in the tracking direction (Thin line). Generally, the condensing 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 condensing lens on the optical disc is RMS.
Considering that the value is about 0.07λ or less (where λ indicates the wavelength of light), the amount of occurrence of aberration is relatively large, and the condition of light incidence on the condenser lens 17 becomes tight. If the amount of wavefront aberration is 0.07λ or less when the shift amount of the condenser lens 17 with respect to the light from the light emitting point 9a is maximum (500 μm), the light from either of the light emitting points is
Is considered to be converged on the optical disk regardless of the shift amount of the condenser lens 17. As a range that satisfies this condition, as is apparent from FIG.
It can be seen that the ratio of L3 to L4 (L4 ÷ L3 = H, hereinafter represented by H) preferably satisfies 0.55 ≦ H ≦ 0.75.

If this range is satisfied, the amount of wavefront aberration generated in the light reflected and returned by the recording medium can be suppressed, so that the light can be satisfactorily incident on the light receiving element that receives the reflected light. Thus, excellent signal characteristics can be obtained.

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
0.55 ≦ 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-described 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.

Therefore, since only one condenser lens 17 is required, it is possible to reduce the number of condenser lenses and to provide no means for switching the condenser lens 17, thereby reducing the size of the optical pickup and reducing the number of parts. It is possible to realize an improvement in productivity by reduction, an improvement in reliability of the optical pickup by eliminating a complicated mechanism, an improvement in operation speed, and the like.

In the present embodiment, the collimator lens 16 is used.
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
Indicates the distance from the condenser lens 17 to the light emitting point 2a, and L4 indicates the distance 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) Embodiment 2 of the present invention will be described below 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. The package 20 has a light source 2 for emitting light for the high-density optical disk 18, a light source 9 for emitting light for the low-density optical disk 19, and the light source 2 and the light source 9. Light source mounting part 160,
161, high-density optical disk 18, and low-density optical disk 1
The light receiving element 21 for receiving the light reflected by the light receiving element 9 and the like are formed by a substrate portion 20a on which the light receiving element 21 and the like are mounted, and a side wall portion 20b provided so as to include those members. The substrate 20a, the side wall 20b, and the terminals constituting the package 20 have substantially the same configuration as the substrate 1a, the side wall 1b, and the terminal 1c of the first package 1 except for the size.

Next, the light source mounting section 160 on which the light source 2 is mounted will be described. The light source mounting portion 160 has a rectangular parallelepiped shape or a plate shape, and has a light source 2 on its upper surface or side surface.
Is attached. The light source mounting portion 160 is provided on the substrate portion 20a or the side wall portion 20b, and has a function of mounting the light source 2 and releasing heat generated by the light source 2. In consideration of heat conduction, etc., in joining the light source mounting portion 160 and the light source 2, a solder such as Au-Sn is plated in advance on the upper surface of the light source mounting portion 160, and a method of soldering at a high temperature or an Au- Sn, Sn-Ag, Sn-Sb, S
It is preferable to use a method of pressing a foil (thickness of several μm to several tens of μm) such as n-Pb-In at a high temperature.

If the light source 2 is not mounted substantially parallel to the mounting surface of the light source mounting portion 160, aberrations of the optical system and a decrease in coupling efficiency may be caused. Therefore, at the time of bonding, it is preferable that the light source 2 be mounted on the light source mounting portion 160 at a predetermined position at a predetermined height and substantially parallel to the mounting surface.

Next, an electrode surface is provided on the upper surface of the light source mounting portion 160 so as to be in electrical contact with the lower surface of the light source 2. This electrode surface is used to supply power to the light source 2, and the metal film constituting the electrode surface is made of A in consideration of conductivity and corrosion resistance.
It is preferable to use a thin film of u.

Further, the light source mounting portion 160 has high heat conductivity due to problems such as heat generated from the light source 2 and attachment to the light source 2.
In addition, the coefficient of linear expansion is that of the light source 2 (about 6.5 × 10 ⁻⁶ /
C) are preferred. Specifically, the coefficient of linear expansion is 3
A substance having a thermal conductivity of 100 W / mK or more at 〜１０10 × 10 ⁻⁶ / ° C., such as AlN, SiC, T-cBN, Cu
/ W, Cu / Mo, Si, and the like, and particularly, when a high output light source 2 is used, and when the thermal conductivity must be extremely large, it is preferable to use a diamond or the like.

When the linear expansion coefficients of the light source 2 and the light source mounting portion 160 are set to be the same or close to each other, the occurrence of distortion between the light source 2 and the light source mounting portion 160 can be suppressed. It is possible to prevent inconveniences such as detachment of the mounting portion between the light source 2 and the light source mounting portion 160 and cracking of the light source 2. However, if the distance is out of this range, a large distortion occurs between the light source 2 and the light source mounting portion 160, and the mounting portion between the light source 2 and the light source mounting portion 160 is detached, and a crack or the like is generated in the light source 2. It is more likely to occur.

Further, by setting the thermal conductivity of the light source mounting section 160 as large as possible, the heat generated in the light source 2 can be efficiently released to the outside. However, when the thermal conductivity is equal to or less than this limit, the heat generated by the light source 2 is difficult to escape to the outside, so the temperature of the light source 2 rises, and the wavelength of the light emitted from the light source 2 shifts, The convergence position of the light on the recording medium is slightly different, so that many noise components are mixed in the reproduced signal, or the output of the light source 2 is reduced, so that the recording / reproducing operation on the recording medium cannot be performed normally. In addition, inconveniences such as shortening of the life of the light source 2 and destruction of the light source 2 in the worst case are likely to occur. In the present embodiment, these two
AlN, which is very excellent in both of the three characteristics, was used.

Further, a thin film is formed on the light source mounting surface of the light source mounting portion 160 in order of Ti, Pt, and Au from the light source mounting portion 160 toward the light source 2 in order to improve the bonding property with the light source 2. Is preferred. When Si is used as the material of the light source mounting section 160, it is preferable to form an insulating layer such as an Al ₂ O ₃ film or a surface oxide film on the member surface before the Ti layer.

Next, the light source mounting portion 161 for mounting the light source 9 will be described. The light source mounting portion 161 has a rectangular parallelepiped shape or a plate shape, and has a light source 9 on its upper surface or side surface.
Is attached. The light source mounting portion 161 is provided on the substrate portion 20a or the side wall portion 20b.
And has the function of releasing the heat generated by the light source 9. When heat conduction and the like are taken into consideration in joining the light source mounting portion 161 and the light source 9, as in the case of the light source mounting portion 160, heat conduction due to the heat generated by the light source 9 and the problem of attachment to the substrate portion 20 a, It is preferable to use a material having a high coefficient of thermal expansion and a linear expansion coefficient close to those of the light source 9 and the substrate portion 20a.

However, since the amount of heat generated from the light source 9 is not so large as compared with that from the light source 2, the requirements for these characteristic values are not so strict as compared with the light source mounting section 160. Therefore, the light source mounting portion 161 has a linear expansion coefficient close to that of the light source 9 (about 6.5 × 10 ⁻⁶ / ° C.)
In addition, in consideration of the output ratio between the light source 2 and the light source 9, it is preferable to use a material whose thermal conductivity is 1/5 or more of that of the light source mounting portion 160.

Specifically, the coefficient of linear expansion is 3 to 10 × 10 ^-6
It is preferable to use a substance having a thermal conductivity of 20 W / mK or more at / C. For example, as such a material, Mo, C may be used in addition to those shown in the example of the material of the light source mounting unit 160.
u, Fe, FeNiCo alloy, FeNi alloy, etc.
Here, the light source mounting portion 161 is formed of a material such as Cu or Mo which is very inexpensive as compared with the AlN having the light source mounting portion 160 formed thereon and has relatively excellent characteristics.

It is preferable that the area of the light source mounting section 160 in contact with the substrate section 20a or the side wall section 20b is larger than that of the light source mounting section 161 to increase the contact area with the substrate section 20a or the side wall section 20b. . With such a configuration, heat generated in the light source 2, which generally generates more heat than the light source 9, can be transmitted to the substrate portion 20 a or the side wall portion 20 b particularly well. Therefore, even when a semiconductor laser having a low resistance to high temperatures is used, the temperature during use of the light source 2 can be prevented from becoming significantly higher than that of the light source 9, and as a result, the life of the light source 2 is reduced. It is no longer shorter than the life of the optical pickup, so that the life of the optical pickup can be relatively prolonged and the reliability can be improved.

As described above, in a pickup in which light from a plurality of light sources having different oscillation wavelengths is guided to a predetermined optical path by one optical member having a plurality of optical elements,
The amount of heat conduction of the light source mounting portions of the plurality of light sources is made different, for example, the amount of heat conduction of the light source mounting portion on which a high-output light source is mounted is increased, and Since the heat conduction amount of the mounting portion is configured to be small, it is possible to minimize the influence of heat on the light source in any of the plurality of light sources, so that a light source having a large output and a light source having a small output can be used. Variations in the life can be suppressed, and as a result, the life of the optical pickup can be extended and the reliability of the optical pickup can be improved.

Further, the light source mounting portion 161 on which the light source 9 is mounted
Is formed to be smaller than the light source mounting portion 160 on which the light source 2 is mounted.

The light source 2 mounted on the light source mounting portion 160 is used for recording or reproduction of a high-density optical disk, and the light source 9 mounted on the light source mounting portion 161 is used for reproducing a low-density optical disk. It is provided.

For recording on an optical disk, it is common to use a light source with a very high output (normal output 20 watts or more). On the other hand, a light source with a very high output is not required for reproduction on an optical disk. Usually, a light source of several mw class is generally used.

Therefore, the required level of heat radiation between the light source mounting portion 160 on which the light source 2 which may be used for recording is mounted and the light source mounting portion 161 on which the light source 9 used for reproduction is mounted is set. There is a difference, and as one method for coping with this difference, it is effective to make the shape itself different.

That is, the size of the light source mounting portion 160 is made larger than the size of the light source
The heat capacity of the light source 2 is increased so that the heat generated by the light source 2 is efficiently transmitted to the light source mounting portion 160.

With such a configuration, the light source 2
Can be emitted to the light source mounting portion 160 by conduction, and further radiated from the light source mounting portion 160 by conduction to the substrate portion 20a or the side surface portion 20b. Heat can be released very efficiently.

As a result, heat is accumulated around the light source 2 and a shift in the wavelength of light emitted from the light source 2 caused by the light source 2 becoming high in temperature can be suppressed.
Furthermore, since the temperature rise of the light source 2 can be suppressed efficiently, the light source 2 can be prevented from being deteriorated or destroyed by heat, and the reliability of the optical pickup can be improved.

At this time, it is preferable that the amount of heat conducted by the light source mounting portion 160 is larger than the heat conduction amount of the light source mounting portion 161. With such a configuration, heat from the light source 2 having a higher output can be more efficiently released to the outside via the light source mounting portion 160.

Further, in the present embodiment, the light source mounting section 160 and the light source mounting section 161 are in contact with each other. With such a configuration, the heat generated by the light source 2 can be released by conduction to the light source mounting portion 161 in addition to radiation from the light source mounting portion 160 and conduction to the substrate portion 20a. Therefore, the heat radiation efficiency can be further improved.

The light source mounting part 160 and the light source mounting part 161
, The relative position between the light source 2 and the light source 9 can be easily adjusted. That is, when the light source 2 is previously bonded to a predetermined position of the light source mounting portion 160 and the light source 9 is previously bonded to a predetermined position of the light source mounting portion 161, the relative positions are set unless both are brought into contact. It is necessary to groping by hand, but when they are brought into contact, the distance between them is roughly correct, so it is sufficient to perform only delicate positioning in the vicinity, and the time required for positioning It can be greatly reduced.

In the present embodiment, the light source placement section is differentiated by making the shape of the light source placement section different. However, the difference in the volume of the light source placement section has the greatest effect on the amount of heat stored. This is effective because it works effectively.

By making the surface area of the light source mounting part 160 larger than the surface area of the light source mounting part 161, the amount of radiant heat from the surface of the light source mounting part 160 can be increased. By increasing the amount of radiant heat per unit time from the light source mounting portion 160 to the amount of radiant heat from the light source mounting portion 161 per unit time, heat can be efficiently radiated from the light source mounting portion 160 to the outside even by radiation. And the thermal load on the light source 2 can be reduced.

As described above, the physical properties (for example, heat capacity, size, volume, surface area, etc.) of the light source mounting section 160 on which the light source 2 is mounted are determined by the light source mounting section 1 on which the light source 9 is mounted.
By making it different from the physical properties of the light source 61, heat generated from the light source 2 which is likely to be higher in temperature with high output can be efficiently released. Oscillation wavelength shifts or light source 2
Can be prevented from being destroyed by heat.

Further, the temperatures of the light source 2 and the light source 9 during operation can be made substantially the same. That is, since only one of the light sources 2 does not operate at a significantly high temperature, The life of the optical pickup does not largely differ, and thus a highly reliable optical pickup can be provided without the life of the optical pickup being extremely different.

In this embodiment, only two light sources are provided, but three or more light sources may be provided. In that case, the light source mounting portion may be provided for each light source, or a light source having a large output may be separated and provided for each light source, and a light source having a small output may be collectively provided on one mounting portion.

Next, the substrate part 2 of the light source mounting parts 160 and 161
The arrangement at 0a will be described with reference to the drawings. FIG. 17 is a side view near the light source according to the second embodiment of the present invention, and FIG. 18 is a front view near the light source according to the second embodiment of the present invention.

The projections 162 and 163 are formed on the substrate section 20a. The projections 162 correspond to the light source mounting section 160, and the projections 163 correspond to the light source mounting section 161. The protrusions 162 and 163 are respectively mounted on the light source mounting portion 16.
0, 161 is the reference for positioning.
2,163 mainly has a rectangular parallelepiped shape in many cases.

Next, the arrangement of the light source mounting section 160 on the substrate section 20a and the arrangement of the light source mounting section 161 on the substrate section 20a will be described by taking the case of the light source mounting section 160 as an example.

The protrusion 16 formed on the substrate 20a
2 and the side 160 of the light source mounting section 160
The contact positioning of the light source mounting portion 160 can be performed by bringing the light source mounting portion 160 into contact with a. That is, the light source mounting portion 16 is
0 is placed on the surface 20f of the substrate portion 20a, and the light source mounting portion 160 is bonded to the side surface 162a of the projection 162 on which the surface is accurately exposed by a bonding material.

With such a configuration, the light source mounting portion 160 on which the light source 2 is mounted can be easily and accurately arranged at a predetermined position. Less deterioration of optical characteristics due to misalignment of
A high-performance optical head can be obtained.

Here, as a joining material used for joining the light source mounting portion 160 and the substrate portion 20a, it is required to use a metallic joining material such as solder or a photo-curing resin which is cured by ultraviolet light or visible light. It is preferable because it has a bonding strength not less than the value. In particular, when a metallic bonding material is used, the substrate portion 20a
The surface 20f, the side surface 162a of the protrusion 162, and the bottom surface 160b and the side surface 160a of the light source mounting portion 160 are preferably preliminarily subjected to a treatment for improving the bondability, such as providing metal plating.

At this time, the bottom surface 16 of the light source
It is preferable that a corner formed by Ob and the side surface 160a in contact with the protrusion 162 has a predetermined radius or is cut off.

By adopting such a configuration, the substrate 2
Even when the surface 20f of the projection 0a and the side surface 160a of the projection 162 are not orthogonal, the light source mounting portion 160 can be bonded to the substrate portion 20a in a correct posture, and the light source mounting portion 160 is mounted on the light source mounting portion 160. An optical head having good recording / reproducing characteristics in which the optical axis of the light emitted from the light source 2 does not deviate from the predetermined optical axis can be obtained.

Further, the light source 2 mounted on the light source
Are formed so as to face the projection 162, that is, the projection 162 is formed in the extending direction of the rear emission light 2h of the light source 2, and the projection 163 is formed in the extension direction of the rear emission light 9h of the light source 9. Is preferred. This will be described below.

Since the projections 162 and 163 perform accurate positioning of the light source mounting portions 160 and 161, as described above, they may be in contact with any surface as long as they are originally in contact with the light source mounting portions 160 and 161. Absent. However, it is necessary to take measures to prevent the backward emission lights 2h and 9h from the light sources 2 and 9 from being incident on the light receiving element and the optical member and becoming stray light. 163
Therefore, it will be described below.

In this case, the upper surface 1 of the projections 162 and 163
62c and 163c are provided to be inclined with respect to the end faces 2i and 9i where the light emitting points 2g and 9g of the light sources 2 and 9 exist. A film such as a metal or a dielectric having a high reflectivity is formed on the entire surface or a part of the upper surfaces 162c and 163c, and the backward emission lights 2h and 9h emitted from the light emitting points 2g and 9g are formed on the upper surfaces 162c and 163c. It is configured to reflect non-vertically at 163c.

By adopting such a configuration, the rear emission light 2h emitted from the light source 2 can be reflected well in a predetermined direction, and the rear emission light 2h is
This is preferable because it is possible to prevent the light from being reflected or scattered inside the optical member and entering the optical member or the light receiving means as stray light.

The upper surface 162 of the projections 162 and 163
It is preferable that the inclination angles of c and 163c with respect to the end faces 2i and 9i are set in accordance with the diffusion angles of the light emitted from the light sources 2 and 9. Further, it is preferable that the material of the reflection film formed on the upper surfaces 162c and 163c is appropriately selected according to the wavelength and the polarization direction of the light emitted from the light sources 2 and 9.

With such a structure, the upper surface 16
Since the reflectivity and the reflection direction of the rear emission lights 2h and 9h in the light sources 2c and 163c can be optimized, the rear emission lights 2h and 9h emitted from the light sources 2 and 9 are mixed into the light receiving element and the optical member. Can be more efficiently prevented, and an optical head having excellent optical characteristics can be obtained.

The upper surface 162 of the projections 162 and 163
Although c and 163c are formed to have a high reflectance, the absorbance may be increased instead of increasing the reflectance. As a configuration for increasing the absorbance, the upper surface 162c, 1
It is conceivable to provide a light absorbing film on the entire surface or a part of the 63c. As the light absorbing film, a translucent glass or resin material, a Si film, a Ti film, or a Si film + Ti film with a predetermined thickness is often used.

Further, it is preferable to change the thickness of the light absorbing film according to the wavelength of the incident light. In this way, even when light sources having different wavelengths are used, light from each light source can be reliably absorbed.

In the configuration using the light absorbing film, much of the energy of the absorbed light is converted into heat.
The material of the reflective member on which the light absorbing film is formed has good heat dissipation,
It is preferable to use a material having high thermal conductivity. By using such a material, it is possible to suppress the occurrence of inconvenience, such as a change in the composition of the light absorbing film due to a high temperature of the reflective member and a failure to perform a predetermined light absorbing action.

With such a configuration, the light sources 2 and
Light from the light emitting points 2g and 9g of the upper surface 162c and 16g
Since the light from the light emitting points 2g and 9g is hardly reflected by the optical member 3c and becomes stray light, the optical pickup with good signal characteristics can be realized.

In the case of reflecting light, the projections 162, 163 inclined with respect to the end faces 2i, 9i of the light sources 2, 9 are provided.
In this case, the upper surfaces 162c and 163c need not be inclined.

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 surface of the first substrate 22d on the light source side. ing.

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 unit 23 is provided on the light source side end surface of the second substrate 22e.
Is provided in accordance with the optical axis of the light emitted from the light source 2, and serves to reduce the diffusion angle of the light incident from the light source 2, that is, the light emitted from the light emitting point 2 a of the light source 2 is farther from the eye than seen. The light path is converted as if it were emitted from the light emitting point 2e, and has a function of shifting the light emitting point substantially in the direction opposite to the recording medium and 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. 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 24 denotes a filter having a wavelength selectivity. The filter 24 has a function of transmitting substantially the light guided from the light source 2 and substantially reflecting the 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 polarization separation film. The polarization separation 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 １ ／ 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.

Numeral 27 denotes a diffusion angle conversion means. The diffusion angle conversion means 27 is provided on the light source side end face of the second substrate 22e so as to match the optical axis of the 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 9e, 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. Of the light flux reflected from the reflection means 30,
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 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 diffusion angle conversion means 31 reflects most of the light flux formed by the light emitted from the light source 2 as the zero-order light, and forms the light emitted from the light source 9. It is formed so that most of the light flux 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 incoming light flux, It has a configuration capable of forming signals for focusing and tracking.

Numeral 33 denotes a light receiving element. The light receiving element 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 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 supply 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, when an optical element having a high angle dependence, 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 are reduced. The possibility of deterioration is very high. 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 units 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 sources 2 and Diffusion angle conversion means 23, 27 with respect to the optical axis of the light emitted from light source 9
Are arranged substantially vertically.

With this 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 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 having a predetermined shape, and the number of masks can be reduced by forming them on only one surface. 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 second 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.

Further, it is preferable that the space surrounded by the package 20 and the optical member 22 is 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 has 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, whereby 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.

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 are 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.

Further, in this embodiment, the light source 2 and the light source 9 are provided so as to face the second substrate 22e.
That is, light emitted from the light source 2 and the light source 9 is incident on the same surface of the second substrate 22e, is converted into a light beam having predetermined properties by various optical elements formed on the optical member 22, and is guided to the recording medium. It has a configuration that can be used.

With such a structure, the light source 2
The light source 9 can be aligned with the light source side surface 22f of the second substrate 22e as a reference surface. That is, since a plurality of light sources can be positioned with reference to one surface 22f, it is possible to perform positioning with higher precision with respect to various optical elements formed on the optical member 22. That is, it is possible to prevent the deterioration of the optical characteristics caused by the misalignment with respect to the various optical elements provided on the optical member 22. In addition, mutual position adjustment between the light source 2 and the light source 9 can be more easily performed because there is only one reference surface.

Therefore, there is almost no displacement between the light sources and between the light source and the optical element, and a highly reliable optical pickup having good optical characteristics can be realized.

Further, in the present embodiment, the distances from the surface 22f of the second substrate 22e facing the light source to the light sources 2 and 9 are made equal. By arranging the light source 2 and the light source 9 in such a relationship, the light source 2 and the light source 9 can be fixed to, for example, the same parallel plane member, so that the height accuracy of the light source 2 and the light source 9 can be reduced. It can be easily secured. As a result, it is possible to suppress the deterioration of the optical characteristics caused by the lack of the height accuracy, so that an optical pickup having good recording or reproducing characteristics can be realized.

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.

In addition, since light entering the optical member 22 at a portion other than the predetermined optical path 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 whose light spread has been 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 /
The light enters the four-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 high-density optical disk 18.

The light reflected by the high-density optical disk 18 and returned again enters the quarter-wave plate 26, and when passing therethrough, 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, almost passes through the polarization splitting film 25 provided thereafter, and enters the 板 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 therethrough, 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 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 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. 6, L5 indicates the distance from the collimator lens 16 to the virtual light emitting point 2e, and L6 indicates the distance from the collimator lens 16 to the virtual light emitting point 9e. FIG. 7 is a diagram showing the relationship between the amount of wavefront aberration and L5 and L6 depending on whether or not the condenser lens is shifted according to the second embodiment of the present invention. That is, when the ratio of L5 to L6 is changed, the amount of wavefront aberration generated when the condenser lens is incident is shifted by 500 μm in the tracking direction of the condenser lens 17 (thick line) and when there is no shift in the tracking direction (Thin line). 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. 0.07λ
(Where λ represents the wavelength of light). Considering that the light emission point 9a is relatively small, the amount of aberration is relatively large, and the light emission point 9a from the light emitting point 9a where the condition of light incidence on the condenser lens 17 is tight The shift amount of the condenser lens 17 with respect to light is maximum (500 μ
If the wavefront aberration amount at the time of m) is 0.07λ or less, the light from both light emitting points incident on the condenser lens 17 is converged on the optical disk regardless of the shift amount of the condenser lens 17. It is thought that it will be. As a range that satisfies this condition, as is clear from FIG. 7, the ratio of L5 and L6 (L6 ÷ L5 = H, hereinafter represented by H) is 0.50 ≦
It can be seen that it is preferable that H ≦ 0.75.

If this range is satisfied, the amount of wavefront aberration generated in the light reflected and returned by the recording medium can be suppressed, so that the light can be satisfactorily incident on the light receiving element that receives the reflected light. Thus, excellent signal characteristics can be obtained.

Under the same conditions, the wavefront aberration
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
0.53 ≦ 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 within the above-described 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.

Therefore, since only one condenser lens is required,
The number of condenser lenses can be reduced, and there is no need to provide a means for switching the condenser lenses. This improves the productivity by reducing the size of the optical pickup and the number of components, and eliminates the need for complicated mechanisms. Improvements in reliability, operation speed, and the like can be realized.

In the present 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 3 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. Here, the front sectional view in FIG. 9 depicts the optical path in a straight line. 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.

In FIGS. 8 and 9, reference numeral 40 denotes a package. The package 40 includes a light source 2 for emitting light for the high-density optical disk 18, a light source 9 for emitting light for the low-density optical disk 19, and the high-density optical disk 18. 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 terminal 40c have substantially the same configuration as the substrate 1a, side wall 1b and terminal 1c of the first package 1 except for the size.

Next, the light source mounting section 42 will be described. The light source mounting portion 42 has a rectangular parallelepiped shape or a plate shape, and the light sources 2 and 9 are attached to the upper surface or side surfaces thereof. The light source mounting portion 42 is provided on the substrate portion 40a or the side wall portion 40b as a separate member or as a part of the substrate portion 40a or the side wall portion 40b.
And has a function of releasing heat generated by the light sources 2 and 9.

Further, the material forming the light source mounting portion 42 has a linear expansion coefficient of that of the light source 2 and the light source 9 (about 6.5 × 10 ^−6).
/ ° C) is preferred. Specifically, a substance having a linear expansion coefficient of 3 to 10 × 10 ⁻⁶ / ° C. and a thermal conductivity of 100 W / mK or more, for example, AlN, SiC, T-cBN, C
It is preferable to use u / W, Cu / Mo, Si, and the like, and particularly to use a diamond or the like when a high output light source is used and the thermal conductivity must be extremely large.

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 the light sources 2 and 9 and the light source mounting portion 42 is suppressed. Therefore, it is possible to prevent the light source 2 and the light source 9 from being attached to the light source mounting portion 42 and to prevent the light source 2 and the light source 9 from being cracked.

Further, by making the thermal conductivity of the light source mounting portion 42 as large as possible, the heat generated by the light sources 2 and 9 can be efficiently released to the outside.

With such a structure, the light source 2
In addition, the temperature of the light source 9 rises, the wavelength of the light emitted from the light source 2 and the light source 9 shifts, the convergence position of the light on the recording medium is slightly different, and many noise components are included in the reproduced signal. Mixing, the output of the light source 2 and the light source 9 are reduced, and the recording / reproducing operation on the recording medium cannot be performed normally. Furthermore, the life of the light source 2 and the light source 9 is shortened. Can prevent inconvenience such as the light source 2 and the light source 9 being destroyed.

Next, the arrangement of the light source mounting portion 42 on the substrate portion 40a will be described with reference to the drawings. FIG. 19 is a side view near the light source according to the third embodiment of the present invention, and FIG. 20 is a front view near the light source according to the third embodiment of the present invention.

A projection 170 is formed on the substrate portion 40a, and serves as a reference for positioning the light source mounting portion. The projection 170 often has a rectangular parallelepiped shape.

Projection 17 formed on substrate portion 40a
By bringing the side surface portion 170a of the “0” into contact with the side surface 42a of the light source mounting portion 42, the positioning of the light source mounting portion 42 can be accurately performed. That is, the light source mounting portion 42 is placed on the front surface 40f of the substrate portion 40a in advance, and the light source mounting portion 42 is
The side surface 17 of the protrusion 170 on which the surface is accurately exposed
It is joined with a joining material while pressing against 0a.

With such a structure, the light sources 2 and
The light source mounting portion 42 on which the light source 9 is mounted can be more easily and accurately arranged at a predetermined position, and the deterioration of the optical characteristics due to the displacement of the light sources 2 and 9 is small. A high-performance optical head can be obtained.

Here, as the joining material used for joining the light source mounting portion 42 and the substrate portion 40a, it is required to use a metallic joining material such as solder or a photo-curing resin which is cured by ultraviolet light or visible light. It is preferable because it has a bonding strength not less than the value. In particular, when a metallic bonding material is used, the substrate portion 40a
The surface 40f, the side surface 170a of the protrusion 170, and the bottom surface 42b and the side surface 42a of the light source mounting portion 42 are preferably preliminarily subjected to a treatment such as providing metal plating to improve the bonding property.

At this time, the bottom surface 42b of the light source
It is preferable that a corner formed by the side surface 42a in contact with the protrusion 170 has a predetermined radius or is cut off.

With such a configuration, the substrate section 4
Even when the surface 40f of the projection 0a and the side surface 42a of the projection 170 are not orthogonal, the light source mounting portion 42 can be bonded to the substrate portion 40a in a correct posture, and the light source mounting portion 42 is mounted on the light source mounting portion 42. It is possible to provide an optical head having good recording and reproducing characteristics in which the optical axis of the light emitted from the light sources 2 and 9 does not deviate from the predetermined optical axis.

Further, the light sources 2 mounted on the light source
9 are formed so as to face the projections 170, that is, the projections 17 extend in the extending direction of the rear emission lights 2 h and 9 h of the light sources 2 and 9.
Preferably, 0 is formed. This will be described below.

As described above, the projection 170 is provided on the light source mounting section 42.
Since it is intended to perform accurate positioning, any surface may be contacted as long as it is originally in contact with the light source mounting portion 42. However, it is necessary to take measures to prevent the backward emitted lights 2h and 9h from the light sources 2 and 9 from entering the light receiving element and the optical member and becoming stray light. I am giving.

In this case, the upper surface 170c of the projection 170
Is the end face 2 where the light emitting points 2g and 9g of the light sources 2 and 9 exist.
i, 9i. Then, a film such as a metal or a dielectric having high reflectivity is formed on the entire surface or a part of the upper surface 170c, and the light emitting point 2 is formed.
The rear emission lights 2h and 9h emitted from g and 9g are non-perpendicularly reflected on the upper surface 170c.

With this configuration, the light sources 2 and
9 can be reflected well in a predetermined direction, and the rear emission light 2h, 9h can be reflected in a predetermined direction.
This is preferable because h can be prevented from being reflected and scattered inside the package 1 and entering the optical member, the light receiving means, and the like as stray light.

As described in the first and second embodiments, a light absorbing film may be provided on the upper surface 170c of the projection 170.

In particular, as shown in this embodiment, a plurality of light sources are mounted on one light source mounting portion, and the light source mounting portions are pressed against the projections and joined to each other, so that each light source has Unlike the case where the light source mounting portion and the projection are provided, the configuration is simple and the assembly is easy, so that the productivity of the optical head can be improved. Further, since the inclination direction of the projection is made non-parallel to the light source mounting surface of the light source mounting portion, it is not necessary to change the inclination direction for each light source, and the process of forming the inclined surface is simplified. And the productivity can be further improved.

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 particularly preferably has a configuration in which a surface on which light is incident and a surface on which light is emitted are 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. Further, the first slope 41a and the second slope 41a
Various optical elements are formed on the inclined surface 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, but may be formed as one large reflection film on almost the entire first slope 41a. 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.

[0229] 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 component emitted from the light source 2 and the light source 9 and reflect the P-polarized component.

The polarization separating films 45 and 46 can guide the 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 it is possible to obtain a predetermined amount of light on the board surface with a small output, so that the life of the light source 2 and the light source 9 can be extended.

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 polarized light separating films 45 and 46 are used as a means for separating outgoing light and return light. However, these light separating means such as a half mirror may be used according to the required surface light quantity. May be used.

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 face of the second optical member 47 on the side opposite to the light source 9 so as to match the optical axis of the light emitted from the light source 9. The function of making the diffusion angle negative, that is, the light emitting point 9 of the light source 9
The light emitting point a has a function of changing the optical path so that the light emitted from the point a is closer to the surface than it looks, and the light emitting point is shifted in a direction substantially approaching the recording 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 9e, 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, 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.

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 sources 2 and 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.

Further, the third optical member 49 includes the first slope 4
9a and a second inclined surface 49b. In particular, the surface on which light is incident and the surface on which light is emitted are substantially perpendicular to the optical axis of the 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.

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

A plurality of beam forming means 50 are 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 with a diffraction grating because a plurality of light beams can be efficiently formed. Here, the configuration is such that three luminous fluxes of zero-order light and ± first-order light generated by the diffraction grating are mainly formed.

The plurality of luminous fluxes formed here are applied to predetermined positions on the tracks 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.

If the three-beam method is not used as the tracking method, the multiple beam forming means 50 need not be provided.

The 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. Therefore, 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 substantially the same optical axis by the third optical member 49.

The light from the light source 9 is incident on the third optical member 49, and the light is split by the beam splitter 50b of the multiple beam forming means 50.
An optical path from the light reflected by the first optical member 41 to the filter 51 is formed so as to travel in a direction substantially perpendicular to a plane including light traveling in the first optical member 41.

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 and 9, the light receiving means 58 and 59, and the optical members 41, 47 and 49 are present 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 having a plurality of optical elements and guided to a predetermined optical path, each of the conventional devices has 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, the productivity is greatly improved, and furthermore, the mounting error of each optical element can be suppressed to the minimum, so that good optical characteristics can be obtained. Characteristics can be realized.

Further, since the loss of light due to the mounting error of each optical element can be minimized, an optical pickup with good light use efficiency can be realized.

Also, 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.

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.

Further, in the present embodiment, the light source 2 and the light source 9 are provided so as to face the surface 41c of the first optical member 41. That is, light emitted from the light source 2 and the light source 9 is incident on the surface 41c of the first optical member 41, and various optical elements formed on the first optical member 41, the second optical member 47, the third optical member 49, and the like. It has a configuration in which the light is converted into a light beam having predetermined properties by an element and guided to a recording medium.

With such a structure, the light source 2
And the light source 9 is a light source side surface 41 c of the first optical member 41.
Can be used as a reference plane. In other words, since a plurality of light sources can be positioned with reference to one surface 41c, it is possible to perform positioning with higher accuracy on various optical elements formed on each optical member. That is, it is possible to prevent the deterioration of the optical characteristics caused by the misalignment with respect to the various optical elements provided in each optical member. In addition, mutual position adjustment between the light source 2 and the light source 9 can be more easily performed because there is only one reference surface.

In the case where no optical element is formed at the position where the light from each light source enters, as in the case of the first optical member 41, the light enters the surface 41c serving as the incident surface. It is necessary to perform very precise processing such as minimizing the surface roughness so that light is not scattered.

Since light from a plurality of light sources is made incident on the same surface of the optical member as in this embodiment, the number of surfaces on which such precision processing is required can be reduced. In addition, the manufacturing process associated with precision processing can be simplified, and the productivity of the optical head is improved. Further, since the production cost for precision processing can be reduced, an inexpensive optical head can be obtained.

Accordingly, there is almost no positional deviation between the light sources and between the light source and the optical element, and a highly reliable optical pickup having good optical characteristics can be realized.

Also, in the present embodiment, the first optical member 41
The distance from the surface 41c facing the light source to the light sources 2 and 9 is made equal. By arranging the light sources 2 and 9 in such a relationship, the light sources 2 and 9
Can be fixed to the same parallel plane member, for example, so that the height accuracy of the light source 2 and the light source 9 can be easily secured. As a result, it is possible to suppress the deterioration of the optical characteristics caused by the lack of the height accuracy, so that an optical pickup having good recording or reproducing characteristics can be realized.

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 and is converted into substantially parallel light, and then directly enters the condenser lens 17 when it is not provided. It converges on the high-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 and almost passes through the filter 51 formed on the second inclined surface 49b.
9, 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 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 having a predetermined shape is formed on 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 53 as it is, and is used for signal formation according to the purpose.

The light reflected by the optical path splitting 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 surface 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 slope 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 enters the third optical member 49 and is almost reflected by the filter 51 formed on the second inclined surface 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 exits from the third optical member 49 and enters 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. About half of the incident light is transmitted and almost half is reflected by the light path dividing means 55.

Then, the light transmitted through the optical path dividing means 55 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 59 provided on the lower surface of the fourth optical member 53 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. The distances between the light emitting points 2a and 9a (9e) of the light sources 2 and 9 and the collimating lens are optimized. However, since the concept is the same as in the second embodiment, the description is omitted here.

As described above, in the present embodiment, the light source 2 and the light source 9 are arranged on the 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. doing. That is, the light emitting point 2a of the light source 2 and the light emitting point 9 of the light source 9
The straight line connecting to the line a 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 use frequency in the in-plane direction parallel to the recording medium is made higher than the use frequency 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.

Embodiment 4 Hereinafter, Embodiment 4 of the present invention will be described 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. Here, the front sectional view in FIG. 11 depicts the optical path in a straight line. 10 and 11, the same reference numerals are given to members having the same configuration as in the third embodiment.

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.

Next, the light source mounting section 71 will be described with reference to FIG. FIG. 13 is a perspective view of the vicinity of the light source according to the fourth embodiment of the present invention. Light source mounting portion 71 has substantially the same configuration as light source mounting portion 42 shown in Embodiment 3, and
Since substantially the same material is used and has substantially the same function, only a portion substantially different from the light source mounting portion 42 will be described.

The light source mounting portion 180 on which the light source 2 is mounted and the light source mounting portion 72b on which the light source 9 is mounted do not have their upper surfaces on the same plane. That is, assuming that the light source mounting portion 180 and the light source mounting portion 181 exist on the same plane on the same substrate, the light source mounting portion 180 and the light source mounting portion 181 have different heights. Then, a first optical member 72 described later.
Is provided on the upper surface of the light source mounting portion having the higher height.

In the present embodiment, the light source mounting portion 18
The light source mounting portion 181 and the light source mounting portion 181 are mounted on the same substrate 70a, and the height of the light source mounting portion 181 is formed higher than the height of the light source mounting portion 180. One optical member 72 is placed and joined.

With such a configuration, first, only the upper surface of the light source mounting portion 181 needs to be finished to bond the first optical member 72. The surface grinding step can be eliminated, and the productivity can be improved.

Also, the light source mounting part 180 and the light source mounting part 1
As compared with the case where the first optical member 72 is placed on each of the upper surfaces of the optical members 81, the possibility that the optical characteristics are deteriorated can be reduced.

That is, the first optical member 72 is connected to the light source
In the case where the light source mounting portion 180 and the light source mounting portion 181 are mounted on both upper surfaces, the heights of the light source mounting portion 180 and the light source mounting portion 181 need to be exactly the same. The light source mounting part 180 and the light source mounting part 18
If the height of the first optical member 72 is slightly different from that of the first optical member 72, a phenomenon occurs in which the first optical member 72 is inclined at an angle corresponding to the difference in the height. Such an inclination of the first optical member 72 causes an aberration to be generated in the light incident from the light source 2 or the light source 9, and further, an optical characteristic which should be given when passing through the first optical member 72 is accurately given. In addition, the light emitted from the first optical member 72 may not be able to be guided to a predetermined position.

On the other hand, according to the configuration of the present embodiment, the mounting surface of the first optical member 72 is the upper surface of one of the plurality of light source mounting portions 180 and 181. A predetermined function of the first optical member 72 is realized by accurately exposing only the upper surface of any one of the light source mounting portions without causing the inclination of the first optical member due to a height shift between the mounting portions. can do. Therefore, it is preferable because an optical head having excellent performance without deterioration of optical characteristics can be realized with a simple configuration.

Next, the substrate section 7 of the light source mounting sections 180 and 181
The arrangement at 0a will be described with reference to the drawings. FIG. 21 is a side view near the light source according to the second embodiment of the present invention.

A projection 182 is formed on the substrate portion 70a, and serves as a reference for positioning the light source mounting portions 180 and 181, and the projection 182 often has a rectangular parallelepiped shape.

Projection 18 formed on substrate 70a
By bringing the second side surface portion 182a into contact with the side surface portions 180a, 181a of the light source placement portions 180, 181, the placement of the light source placement portions 180, 181 can be determined. That is, the light source mounting sections 180 and 181 are previously attached to the substrate section 70a.
Side surface 182 of the projection 182 on which the light source mounting portions 180 and 181 are accurately exposed.
It is joined with a joining material while pressing against a.

With such a structure, the light sources 2 and
The light source mounting portions 180 and 181 on which the light sources 9 are mounted can be more easily and accurately arranged at predetermined positions, and deterioration of optical characteristics due to displacement of the light sources 2 and 9 can be prevented. A small, high-performance optical head can be obtained.

Here, as a joining material used for joining the light source mounting portions 180 and 181 and the substrate portion 70a, a metallic joining material such as solder or a photo-curing resin which cures with ultraviolet light or visible light is used. Is preferable because it has a bonding strength equal to or higher than the required value. In particular, when a metallic bonding material is used, the surface 70f of the substrate 70a, the side surface 182a of the projection 182,
It is preferable that the bottom surfaces 180b, 181b and the side surfaces 180a, 181a of the light source mounting portions 180, 181 are preliminarily subjected to a treatment for improving bonding properties such as providing metal plating.

At this time, it is preferable that corners formed by the bottom surfaces 180b, 181b of the light source mounting portions 180, 181 and the side surfaces 180a, 181a in contact with the projections 182 have a predetermined radius or are cut off.

With such a configuration, the substrate section 7
Even when the surface 70f of the projection 0a and the side surface 180a of the projection 182 are not orthogonal to each other, the light source placement sections 180 and 181 can be bonded to the substrate section 70a in an accurate posture, and the light source placement section 180 , 181 can be an optical head having good recording / reproducing characteristics in which the optical axis of light emitted from the light sources 2 and 9 mounted on the optical disk does not deviate from a predetermined optical axis.

Further, the light sources 2 and 9 mounted on the light source mounting portions 180 and 181 are formed so as to face the projections 182.
That is, the backward emission light 2h of the light source 2 and the backward emission light 9h of the light source 9
It is preferable that the protrusion 182 is formed in the extending direction of. This will be described below.

As described above, the projection 182 is provided on the light source mounting portion 18.
Since the positions 0 and 181 are accurately positioned, any surface may be in contact with the light source mounting portions 180 and 181 as long as it is originally in contact therewith. However, it is necessary to take measures to prevent the backward emission lights 2h and 9h from the light sources 2 and 9 from entering the light receiving element and the optical member and becoming stray light. In the present embodiment, this measure is applied to the protrusion 182. I am giving.

In this case, the upper surface 182b of the projection 182,
182c is provided to be inclined with respect to the end faces 2i, 9i where the light emitting points 2g, 9g of the light sources 2, 9 exist. Then, a film such as a metal or a dielectric having a high reflectance is formed on the entire surface or a part of the upper surfaces 182b and 182c, and the backward emission lights 2h and 9h emitted from the light emitting points 2g and 9g are formed on the upper surfaces 182b and 182c. It is configured to reflect non-vertically at 182c.

With this configuration, the light sources 2 and
9 can be reflected well in a predetermined direction, and the rear emission light 2h, 9h can be reflected in a predetermined direction.
It is possible to prevent h from being reflected and scattered inside the package 70 and entering as stray light into an optical member, a light receiving unit, or the like.

The upper surfaces 182b, 182 of the projections 182
It is preferable that the inclination angle of c with respect to the end faces 2i, 9i is set according to the diffusion angle of the light emitted from the light sources 2, 9. Further, it is preferable that the material of the reflection film formed on the upper surfaces 182b and 182c is appropriately selected according to the wavelength and the polarization direction of the light emitted from the light sources 2 and 9.

With such a configuration, the upper surface 18
Since the reflectivity and the reflection direction of the backward emission lights 2h and 9h in the light emission elements 2b and 182c can be optimized, the backward emission lights 2h and 9h emitted from the light sources 2 and 9 are mixed into the light receiving element and the optical member. Can be more efficiently prevented, and an optical head having excellent optical characteristics can be obtained.

Also, the upper surfaces 182b, 182 of the projections 182
Although c is formed to have a high reflectance, the light absorption may be increased instead of increasing the reflectance. As a configuration for increasing the light absorption, it is conceivable to provide a light absorbing film on the entire surface or a part of the upper surfaces 182b and 182c.
As the light absorbing film, a translucent glass or resin material, a Si film, a Ti film, or a Si film + Ti film with a predetermined thickness is often used.

Further, the thickness of the light absorbing film is preferably changed according to the wavelength of the incident light. In this way, even when light sources having different wavelengths are used, light from each light source can be reliably absorbed.

In the structure using the light absorbing film, much of the energy of the absorbed light is converted into heat.
The material of the reflective member on which the light absorbing film is formed has good heat dissipation,
It is preferable to use a material having high thermal conductivity. By using such a material, it is possible to suppress the occurrence of inconvenience, such as a change in the composition of the light absorbing film due to a high temperature of the reflective member and a failure to perform a predetermined light absorbing action.

With such a configuration, the light sources 2 and
Light from the light emitting points 2g and 9g of the upper surface 182b and 18g
Since the light from the light-emitting points 2g and 9g is hardly reflected by 2c and absorbed by the optical member, it hardly becomes stray light, so that an optical pickup with good signal characteristics can be realized.

In the case of reflecting light, the upper surface 1 of the projection 182 which is inclined with respect to the end surfaces 2i and 9i of the light sources 2 and 9 is used.
82b and 182c need not be inclined in this case.

Furthermore, in the present embodiment, the height of the light source mounting portion 181 is formed higher than the height of the light source mounting portion 180, and the first optical member 72 is mounted on the upper surface of the light source mounting portion 181.・ It is joined.

In the present embodiment, the light source mount 18
The light source 2 mounted on the light source 0 is used for recording or reproduction of a high-density optical disk, and the light source 9 mounted on the light source mounting part 181 is used for reproducing a low-density optical disk.

For recording on an optical disc, it is common to use a light source with a very high output (normal output of 20 mw or more), whereas for reproduction on an optical disc,
A light source with a very large output is not required, and is usually several mw.
It is common to use class light sources. Also, the heat emitted from the light source generally increases as the output increases.

In the configuration in which the optical member is mounted on the upper surface of the light source mounting portion as in this embodiment, the heat emitted from the light source and transmitted through the light source mounting portion is likely to cause a problem. In particular, since the amount of heat emitted from the light source 2 having a larger output is considerably large, the temperature of the first optical member 72 when the light source 2 is turned on and the temperature of the first optical member 72 when the light source 2 is not operating A large temperature difference occurs, and this temperature difference causes a distortion in the first optical member 72 formed of optical glass or the like, so that a predetermined optical characteristic cannot be obtained or a plurality of prisms are laminated. There is a possibility that the joint surface between the prisms of the first optical member 72 may be distorted, cracks may occur in the joint portion, and the first optical member 72 may be broken.

Therefore, in the present embodiment, the height of the light source mounting portion 181 on which the light source 9 is mounted is formed higher than the height of the light source mounting portion 180 on which the light source 2 is mounted, and the height is increased. As described above, the first optical member 72 is mounted on the upper surface of the light source mounting portion 181 to prevent heat generated by the light source 2 from being conducted to the first optical member 72 via the light source mounting portion 180. The occurrence of inconvenience is suppressed.

Thus, even when a light source having a large output is provided inside the optical head, inconvenience due to the influence of heat generated from the light source can be minimized, the optical characteristics are stable, and the reliability is high. An optical head having excellent performance can be realized.

The first optical member 72 has a function of guiding light emitted from the light source 2 and the light source 9 to a predetermined optical path, and guiding light reflected by the optical disk and returned to the predetermined optical path.

The first optical member 72 has a first inclined surface 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 on b and the third inclined surface 72c.

Hereinafter, various optical elements present 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. However, the reflection film 73 and the reflection film 74 may be formed on almost the entire first inclined surface 72a as one large reflection film. 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.

[0334] Then, the polarization separation films 75 and 76 are formed on the second inclined surface 72b. Light emitted from the light source 2 and reflected by the reflection film 73 enters the polarization separation film 75, and light emitted from the light source 9 and reflected by the reflection film 74 enters the polarization separation film 76. . 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 separation films 75 and 76 are formed by alternately providing a plurality of layers of a plurality of dielectric materials having different refractive indexes 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 splitting films 75 and 76 can guide the amount of light passing through to the recording medium without substantially reducing the amount of light, 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 it is possible to obtain a predetermined amount of light on the board surface with a small output, so that the life of the light source 2 and the light source 9 can be extended.

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 a means for separating outgoing light and return light. However, these light splitting means may use a splitting 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 configuration as the reflecting films 56 and 57 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 83,
84, the fourth optical member 5 shown in the third embodiment.
3 optical path dividing means 5 formed on the first slope 53a
Since it has almost the same configuration and function as 4,55,
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 91, 92, etc. are arranged be sealed. With 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 sources 2 and 9 and the light receiving units 91 and 92 can be maintained and emitted. Also, the deterioration of the optical characteristics of the light can 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 condensation can be prevented from occurring on the surface of the light source and the like, thereby deteriorating the optical characteristics and the deterioration of the characteristics due to oxidation of the light sources 2 and 9 and the light receiving means 91 and 92.

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 transmitting 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 through which 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.

Then, 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.

Then, 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, which is a 波長 wavelength plate.
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.

Both light receiving means 91 and 92 receive the light transmitted through the light path dividing means 83 and the light reflected by the reflecting film 81 after being reflected by the light path dividing means 83 and receiving the light. 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 dispersed manner, and each light source can be reduced. This eliminates the need for alignment 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 incident on the optical members 72 and 86 on which a plurality of optical elements are formed, and are 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.

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.

In this embodiment, the light source 2 and the light source 9 are provided so as to face the surface 72d of the first optical member 72. That is, light emitted from the light source 2 and the light source 9 is incident on the surface 72d of the first optical member 72, and has predetermined properties by various optical elements formed on the first optical member 72, the second optical member 86, and the like. It is configured to be converted into a luminous flux and guided to a recording medium.

With such a configuration, the light source 2
And the light source 9 is provided on the light source side surface 72 d of the first optical member 72.
Can be used as a reference plane. In other words, since a plurality of light sources can be positioned with reference to one surface 72d, it is possible to perform positioning with higher accuracy on various optical elements formed on each optical member. That is, it is possible to prevent the deterioration of the optical characteristics caused by the misalignment with respect to the various optical elements provided in each optical member. In addition, mutual position adjustment between the light source 2 and the light source 9 can be more easily performed because there is only one reference surface.

In the case where no optical element is formed at the position where the light from each light source enters, as in the case of the first optical member 72, the light enters the surface 72d serving as the incident surface. It is necessary to perform very precise processing such as minimizing the surface roughness so that light is not scattered.

[0364] Since the light from the plurality of light sources is made incident on the same surface of the optical member as in the present embodiment, the number of surfaces that must be subjected to such precision processing can be reduced. In addition, the manufacturing process associated with precision processing can be simplified, and the productivity of the optical head is improved. Further, since the production cost for precision processing can be reduced, an inexpensive optical head can be obtained.

Therefore, there is almost no displacement between the light sources and between the light source and the optical element, and a highly reliable optical pickup having good optical characteristics can be realized.

In this embodiment, the first optical member 72
The distance from the surface 72d facing the light source to the light sources 2 and 9 is made equal. By arranging the light sources 2 and 9 in such a relationship, the light sources 2 and 9
Can be fixed to the same parallel plane member, for example, so that the height accuracy of the light source 2 and the light source 9 can be easily secured. As a result, it is possible to suppress the deterioration of the optical characteristics caused by the lack of the height accuracy, so that an optical pickup having good recording or reproducing characteristics can be realized.

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.

After that, 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 the collimator lens 16 and is converted into substantially parallel light. It converges on the high-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 inclined surface 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.

The second slope 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 and is transmitted through the polarization splitting film 88a and is separated into one main beam and two side beams when reflected by the beam splitting portion 88b, and then 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 having passed through the quarter-wave plate 90 is incident on the second optical member 86, and is almost reflected by the filter 89 formed on the second inclined surface 86e of the second substrate 86b. 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 is converted in divergence angle, becomes convergent light, is emitted from the second optical member 86, passes through the shield member 85, 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.

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 splitting 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. .

In the case where a plurality of light sources are arranged in the same package as described above, similarly to the second embodiment, the wavefront aberrations generated in the lights emitted from the respective light sources often differ greatly. The distances between the light emitting points 2a and 9a (9e) of the light sources 2 and 9 and the collimating lens are optimized. However, since the concept is the same as in the first and second embodiments, the description is omitted here. .

As described above, in the present embodiment, the light source 2 is provided on the side surface portion 180 of the light source mounting portion 71 as described above.
And the light source 9 are disposed at substantially the same height from the bottom surface of the light source mounting portion 71. 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 this arrangement, the first plane including the optical axis formed when the light emitted from the light source 2 passes through the first optical member 72, and the light emitted from the light source 9 A second plane including an optical axis formed when passing through the first optical member 72 and a third plane including an optical axis formed when light emitted from the light source 9 passes through the second optical member 86 It 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 which 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 the present 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.

In the first to fourth embodiments, an optical pickup having a plurality of light sources having different wavelengths has been described by taking recording or reproduction of a high-density optical disk and a low-density optical disk as an example. In addition, the optical pickup can be used for a recording medium in which a plurality of recording layers having different transmittances depending on wavelengths are formed, for example.

In the first to fourth embodiments, an optical pickup having a plurality of light sources having different wavelengths has been described by taking recording or reproduction of a high-density optical disk and a low-density optical disk as an example. In addition, the optical pickup can be used for a recording medium in which a plurality of recording layers having different transmittances depending on wavelengths are formed, for example.

(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) or a low-density disk 19 such as a compact disk (hereinafter abbreviated as CD). Used. Here, the high density disk 18
For example, a disk having a configuration in which two substrates having a recording layer are prepared, and 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.

[0396] Reference numeral 103 denotes an optical pickup unit for recording or reproducing data on or from the disk 101. Its optical part has the structure shown in Embodiment 1 and operates the condenser lens 17 with respect to the disk 101. An actuator 108 is provided.

[0397] As the optical pickup section 103, the one 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 the spindle motor unit 102, the optical pickup unit 103, and the feed unit 104 are mounted.

Reference numerals 106 and 107 denote spindle motor units.
2 and a flexible substrate that supplies power to the optical pickup unit 103.

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 a 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 optical 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.

[0405]

As described above, according to the present invention, since the projection formed on the substrate is brought into contact with the light source mounting portion, the predetermined light source mounting portion on which the light source is mounted is provided. Can be more simply and accurately arranged, and a high-performance optical head with less deterioration in optical characteristics due to displacement of the light source can be provided.

At this time, the corner formed by the bottom surface of the light source mounting portion and the side surface in contact with the projection has a predetermined radius or is cut off, so that the surface of the substrate portion and the projection of the projection are formed. Even when the side surface is non-perpendicular, the light source mounting portion can be bonded to the substrate in an accurate posture, and the optical axis of the light emitted from the light source mounted on the light source mounting portion is predetermined. An optical head having good recording / reproducing characteristics that does not deviate from the optical axis can be obtained.

Further, a film of a metal or a dielectric having high reflectivity is formed on the entire surface or a part of the upper surface of the protruding portion, and the backward emitted light emitted from the light emitting point is non-perpendicularly reflected on the upper surface. With such a configuration, both the backward emission light emitted from the light source can be reflected well in a predetermined direction, and the backward emission light is reflected and scattered inside the package and is reflected on the optical member and the light receiving means. It is possible to prevent the light from entering as stray light.

[0408] Further, since the light absorption from the light source is absorbed by the upper surface of the protruding portion without being substantially reflected by the upper surface, the backward emitted light enters the optical member and becomes stray light. And the optical pickup having good signal characteristics can be realized.

[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 amount of wavefront aberration and L
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 condenser lens is shifted according to the second embodiment 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 perspective view of the vicinity of a light source according to a fourth embodiment of the present invention.

FIG. 14 is a diagram showing an optical system of a conventional optical pickup.

FIG. 15 is an enlarged view near a light source according to the first embodiment of the present invention.

FIG. 16 is an enlarged view of the vicinity of a light source in an embodiment other than the present invention.

FIG. 17 is a side view of the vicinity of the light source according to the second embodiment of the present invention.

FIG. 18 is a front view showing the vicinity of a light source according to the second embodiment of the present invention.

FIG. 19 is a side view of the vicinity of the light source according to the third embodiment of the present invention.

FIG. 20 is a front view of the vicinity of the light source according to the third embodiment of the present invention.

FIG. 21 is a side view near a light source according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st package 1a Substrate part 1b Side wall part 1c Terminal 1d Emission part 1f Surface 2 Light source 2a, 2g Light emission point 2b, 2c, 2d Light flux 2h Back emission light 2i End face 3 Light receiving element 5 1st optical member 5a 1st slope 5b 2nd slope 6 optical path splitting means 7 reflecting means 8 second package 8a substrate section 8b side wall section 8c terminal 8d emitting section 8f surface 9 light source 9a, 9e light emitting point 9b, 9c, 9d light flux 10 light receiving element 11 second optical Member 11a First slope 11b Second slope 12 Optical path dividing means 13 Reflecting means 14 Quarter wave plate 15 Optical path dividing means 16 Collimator lens 17 Condensing lens 18 High density optical disk 19 Low density optical disk 20 Package 20a Substrate 20b Side wall Part 20c terminal 20f surface 21 light receiving element 22 optical member 22a first slope 22 Second inclined surface 22c Third inclined surface 22d First substrate 22e Second substrate 23 Diffusion angle conversion means 24 Filter 25 Polarization separation film 26 Quarter wave plate 27 Diffusion angle conversion 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 34 light source mounting part 34a surface 40 package 40a substrate part 40b side wall part 40c terminal 40d opening 40f surface 41 first optical member 41a first slope 41b second slope 41c Surface 42 Light source mounting part 42a Side surface 42b Bottom surface 43,44 Reflection film 45,46 Polarization separation film 47 Second optical member 48 Diffusion angle converter 49 Third optical member 49a First slope 49b Second slope 50 Multiple beam formation Means 50a Polarization separation film 50b Beam separation unit 51 Filter 52 1/4 wavelength plate 5 3 Fourth optical member 53a First slope 53b Second slope 54,55 Optical path splitting means 56,57 Reflective film 58,59 Light receiving means 70 Package 70a Substrate 70b Side wall 70c Terminal 70d Opening 180 Light source mounting section 181 Light source mounting part 72 First optical member 72a First slope 72b Second slope 72c Third slope 72d Surface 73,74 Reflective film 75,76 Polarization separation film 77,78 Hologram 79,80 Reflector 81,82 Reflector Films 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 unit 103 Optical pickup unit 104 Feed unit 105 Module base 106, 107 Flexible board 108 Actuator 150 Light source mounting unit 150a Side surface 150b Bottom surface 151 Projection unit 151a Side surface 151c Top surface 152 Light source mounting unit 152a Side surface 152b Bottom surface 153 Projection 153A Side surface 153c Top surface 160, 161 Light source mounting portion 180a, 161a Side surface 160b, 161b Bottom surface 162, 163 Projection portion 162a, 163a Side surface 162c, 163c Top surface 170 Projection portion 170a Side surface 170c Top surface 180, 181 Light source mounting portion 182a Projection portion 182a , 182c upper surface

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

Claims (9)

[Claims] A light source mounting portion on which the light source is mounted; and a substrate having a projection, the substrate having the light source mounting portion mounted thereon, wherein the projection portion, the light source mounting portion, An optical head, wherein the optical head is in contact with the optical head. 2. The light-emitting device according to claim 1, wherein the upper surface of the substrate and the side surface of the projection are not in contact with at least a part of a corner of the light source mounting portion facing the upper surface and the side surface. Optical head. 3. The projection according to claim 1, wherein a reflection means for reflecting light emitted from the light source along a predetermined optical axis in a direction different from the optical axis is formed on the projection. Optical head. 4. The optical head according to claim 1, wherein light absorbing means for absorbing light is formed on the projection. 5. A first light source, a second light source, a first light source mounting portion for mounting the first light source, and a second light source mounting for mounting the second light source. And a projection, wherein the first
A light source mounting portion and a substrate on which the second light source mounting portion is mounted, wherein at least one of the first light source mounting portion and the second light source mounting portion is in contact with the protrusion. An optical head, comprising: 6. The non-contact between the upper surface of the substrate and the side surface of the projection, and at least a part of the corners of the first light source mounting portion and the second light source mounting portion facing the upper surface and the side surface. The optical head according to claim 5, wherein: 7. At least one of a first light source and a second light source is disposed so as to face a projection, and a reflecting means or a light absorbing means is provided on a surface facing the first light source and the second light source. Claim 5, wherein:
6. The optical head according to any one of 6. 8. The optical head according to claim 5, wherein the first light source mounting portion and the second light source mounting portion are made of the same member. 9. A first light source for contacting a projection with a first light source mounting portion.
The optical head according to any one of claims 5 to 7, wherein the optical head is divided into a protrusion and a second protrusion that contacts the second light source mounting portion.