JPH11102534A - Optical pickup and optical head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow different amount of heat to be radiated from first and second light sources so as to suppress difference in temperature between the respective light sources during operation to the minimum level, and improve the lifetime and operation stability of the light sources, by setting the size of the first light source to be different from the size of the second light source. SOLUTION: Light sources 2 and 9 respectively perform recording or reproducing operation for recording mediums different from each other. Since a different amount of light is required, optical outputs as well as temperatures during the operation are different from each other. The size of the light source 2, more specifically, the area, in which the light source 2 is in contact with other components, is made to be different from that of the light source 9. For example, in the case where an output of the light source 2 is larger than that of the light source 9, the contact area of the light source 2 is designed to be larger, thereby allowing a lager amount of heat to be released per unit time by heat conduction, as compared to the light source 9. Furthermore, a larger amount of heat can be radiated from the light source 2 than from the light source 9 by designing a surface area of the light source 2 to be larger than that of the light source 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[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 pickups 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. It is required that reproduction be possible. However, if an optical system designed for a high-density optical disc is used as it is on a conventional optical disc, a large spherical aberration occurs due to the difference in the thickness of the disc substrate, and the image spot is blurred and information cannot be reproduced. Occurs.

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

A conventional technique for solving this problem will be described in detail below. FIG. 13 is a sectional view showing the configuration of a conventional optical pickup. In FIG. 13, 200
And 300 are light sources, and the light source 200 has a wavelength of 635-650 nm used for reproducing a high-density optical disk.
The light source 300 has a wavelength of 7 to be used for reproducing a low-density optical disk and a write-once low-density optical disk (hereinafter collectively referred to as a low-density optical disk).
An 80 nm semiconductor laser. 201 is a prism,
The prism 201 is provided with a half mirror 201a. A collimator lens 202 has a function of converting diffused light into parallel light.
Reference numeral 203 denotes an objective lens holding unit.
Holds a low-density optical disk lens 204 and a high-density optical disk lens 205. The objective lens holding section 203 has a configuration in which the lens can be switched according to the type of the optical disc. 206 is a high-density optical disk, and 207 is a low-density optical disk.

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

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

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

[0009]

However, in such an optical pickup, the average output between the light source 200 and the light source 300 is generally different. This is particularly noticeable when one of them is capable of recording and reproduction and the other is used only for reproduction, and the amount of heat generated by the light source 200 and the light source 300 is greatly different.
There is a problem that the temperature during operation differs between the light source 300 and the light source 300, and the life of the light source and the stability of operation differ for each light source.

An object of the present invention is to provide an optical pickup and an optical head which have a long service life and excellent operation stability and are highly reliable.

[0011]

In order to solve the above-mentioned problems, a first light source mounting portion on which a first light source is mounted and light emitted from the first light source and reflected by a recording medium are provided. First light receiving means for receiving light, a second light source mounting portion for mounting a second light source, and second light receiving for receiving light emitted from the second light source and reflected by the recording medium Means, the first
And the size of the second light source are different.

[0012]

According to the first aspect of the present invention, there is provided a first light source, a first light source mounting portion on which the first light source is mounted, and a recording medium emitted from the first light source. A first light receiving means for receiving the light reflected by the second light source, a second light source,
A second light source mounting portion on which the light source is mounted, and a second light receiving portion that receives light emitted from the second light source and reflected by the recording medium.
Light receiving means, and the first light source and the second light source are different in size, so that an optical pickup having a plurality of different light sources mounted thereon has good heat dissipation from each light source. Can be

According to a second aspect of the present invention, when the average output of the first light source is larger than the average output of the second light source, the first light source is formed to be larger than the second light source. Accordingly, in an optical pickup equipped with a plurality of light sources of different types, the heat radiation from the first light source having a large output can be made better than the heat radiation from the second light source having a small output.

According to a third aspect of the present invention, the area where the first light source is in contact with the first light source mounting portion is equal to the area where the second light source is in contact with the second light source mounting portion. Therefore, in an optical pickup equipped with a plurality of light sources of different types, the amount of heat conduction from the first light source having a large output can be made larger than the amount of heat conduction from the second light source having a small output. it can.

According to a fourth aspect of the present invention, the surface area of the first light source is made larger than the surface area of the second light source. Can be made larger than the amount of heat radiation from the second light source having a small output.

According to a fifth aspect of the present invention, a first light source includes:
A first light source mounting unit for mounting the first light source, a first light receiving unit that receives light emitted from the first light source and reflected by the recording medium, and a second light source; A second light source mounting portion for mounting the second light source, and emitted from the second light source,
Second light receiving means for receiving light reflected by a recording medium, the first light source, the second light source, the first light source mounting portion, and the second light source mounting portion And a storage member for storing the first light receiving means and the second light receiving means, wherein the first light source and the second light source are different in size, so that a plurality of In an optical head having a light source, heat radiation from each light source can be improved.

According to a sixth aspect of the present invention, when the average output of the first light source is larger than the average output of the second light source, the first light source is formed to be larger than the second light source. Accordingly, in the optical head having a plurality of light sources therein, the heat radiation from the first light source having a large output can be made better than the heat radiation from the second light source having a small output.

According to the present invention, the area where the first light source is in contact with the first light source mounting portion is equal to the area where the second light source is in contact with the second light source mounting portion. By being larger than the above, in an optical head having a plurality of light sources inside,
The amount of heat conduction from the first light source having a large output can be made larger than the amount of heat conduction from the second light source having a small output.

According to an eighth aspect of the present invention, the surface area of the first light source is larger than the surface area of the second light source. Can be made larger than the amount of heat radiation from the second light source having a small output.

According to a ninth aspect of the present invention, the first light source and the second light source are formed on the same light source mounting portion.
In an optical head having a plurality of light sources therein, the number of components can be reduced, and alignment between the light sources can be easily performed.

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

FIG. 1 shows a configuration and an optical path of an optical pickup according to Embodiment 1 of the present invention. 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, reference numeral 1 denotes a first package, on which a light source 2 for emitting light for a high-density optical disk, a light receiving element 3 for receiving light reflected by the high-density optical disk, and the like are mounted. And a side wall 1b provided so as to include the substrate portion 1a to be provided. These substrate portion 1a and side wall portion 1b
Etc. may be formed integrally or separately. When formed integrally, the assembly process can be simplified, and productivity can be improved. It is preferable to use a material such as a metal or a ceramic as a material for forming the first package 1 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. In addition, since these materials are low in cost, it is possible to provide an optical pickup at low cost.

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

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

Further, a terminal 1c for supplying power to the light source 2 and transmitting an electric signal from the light receiving element 3 to an arithmetic circuit (not shown) is provided on the substrate 1a. The terminal 1c may be a pin type or a print type. Here, the case where the terminal 1c is formed in a pin type will be particularly described. The terminal 1c is inserted into a plurality of holes (not shown) provided in the substrate 1a while not electrically contacting the substrate 1a made of a metal material. It is preferable to use an FeNiCo alloy, an FeNi alloy, an FeCr alloy or the like as a material of the terminal 1c. As means for cutting off the electrical contact between the substrate part 1a and the terminal 1c, the terminal 1
It is preferable to provide an insulating film or the like at a portion where c is in contact with the substrate portion 1a, and it is preferable that the portion is sealed so that outside air does not enter from this portion. 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 / reproducing, large energy is required to change the state of the recording layer during recording, so that an output of at least 25 (mW) or more is required. However, if the output exceeds 60 mW, it becomes difficult to release the heat emitted from the light source 2 to the outside.
In addition, there is a risk that the life of the light source will be significantly reduced, and in the worst case, the light source will be destroyed. For this reason, the electric circuit may malfunction or the light source 2
It is not preferable because the oscillation itself shifts the wavelength due to wavelength fluctuation, or noise is mixed in the signal, so that the reliability of the optical pickup is greatly reduced.

The first optical member 5 is joined to the emission section 1d of the package 1. The first optical member 5 includes the light source 2
The light emitted from the device and reflected by the recording medium is
Has a function of guiding to a predetermined position. Here, a configuration 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. First
An optical path splitting means 6 composed of a half mirror, a polarization separation film, or the like is formed on the inclined surface 5a.
Is formed with a reflection means 7 for guiding incident light to the light receiving element 3. 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 splitting means 6 is formed of a polarization splitting film, and
Use in combination with the 組 み 合 わ せ wavelength plate 4 is preferable because it improves the light use efficiency and enables recording or reproduction 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 a function of converting the linearly polarized light into elliptically polarized light, and the elliptically polarized light reflected by the recording medium and having its rotation direction reversed is described above. Is converted into linearly polarized light orthogonal to the incident polarization direction.

It is preferable that an optical element corresponding to the purpose (for example, formation of a focus error signal using astigmatism) is arranged at the position of the reflection means 7. For example, when a focus error signal is formed by the knife edge method, an optical element capable of forming a knife edge is formed at the position of the reflecting means 7, and when a focus error signal is obtained by the astigmatism method. At the position of the reflection means 7, an optical element capable of forming astigmatism is formed. 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 can be formed by joining a plurality of dice-shaped prisms in which optical elements are formed in advance in a straight line, or by forming a plate-shaped constituent material. It is preferable to use a method of forming an optical element at a predetermined position, bonding the respective plate-shaped materials together, and cutting the material into a predetermined shape, since good productivity can be obtained. In particular, the latter method is a preferable method because both high productivity and yield can be achieved.

In the present embodiment, the first light emitting portion 1d is provided directly on the side wall portion 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 them, in particular, Fe, FeNi alloy, and FeNiCo alloy have low thermal resistance and good heat dissipation, so that the heat generated by the light source 8 can be efficiently released to the outside. Since these materials are low in cost, it is possible to provide the optical pickup device at low cost.

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

The 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.

In this embodiment, the light source 2
Since the size of the light source 9 differs from that of the light source 9, this point will be described in detail below.

In many cases, the light sources 2 and 9 have different light outputs. This is mainly because the recording medium to be recorded or reproduced is different, and the amount of light required for that is often different. Therefore, the light source 2 and the light source 9 generate different amounts of heat, and accordingly have different temperatures during operation.

Considering the inconvenience that occurs when the temperature of the light source during operation is different, the shift of the oscillation wavelength due to the temperature change and the deterioration of the optical characteristics caused by the temperature change are as follows: Conceivable. Such inconveniences include shorter product life,
It is not preferable because reliability is lowered.

In this embodiment, the size of the light source 2 and the light source 9, specifically, the area in which the light source 2 is in contact with another member, and the size of the light source 9 are controlled so as to suppress the occurrence of this inconvenience. And the area in contact with it. Since the heat generated by the light source is released to the member with which the light source is in contact by conduction, for example, if the output of the light source 2 is larger than the output of the light source 9, the contact area of the light source 2 is reduced. If the contact area is made larger, more heat can be emitted from the light source 2 by conduction per unit time. As a result, it is possible to suppress a large difference between the temperature during the operation of the light source 2 and the temperature during the operation of the light source 9, so that the above-described inconvenience can be suppressed and the life of the product can be prolonged. This is preferable because the reliability can be improved while improving the reliability.

It is also effective to make the surface areas of the light source 2 and the light source 9 different. Generally, radiation (radiation) is a form of heat propagation in addition to the above-described conduction. Since the amount of radiant heat per unit time / unit area depends on the temperature, the amount of radiant heat at the same temperature increases as the surface area increases.

Therefore, if the output of the light source 2 is larger than the light source 9, the amount of radiant heat from the light source 2 is made smaller than the amount of radiant heat from the light source 9 by making the surface area of the light source 2 larger than the surface area of the light source 9. The temperature difference between the light source 2 and the light source 9 during operation can be reduced.
Therefore, it is preferable because it is possible to suppress the occurrence of the above-described inconvenience, to prolong the service life of the product, and to improve the reliability.

As described above, in an optical pickup having a plurality of light sources, the amount of heat radiation from the light sources can be made different by making the size of the light sources different according to the output of each light source. Therefore, the temperature difference during operation of each light source can be suppressed to a minimum, the oscillation wavelength shifts due to the temperature change of the light source, and the optical characteristics deteriorate with it, and the light source deteriorates / destroys due to high temperature, that is, the short life of the light source It is possible to suppress the occurrence of inconveniences such as conversion. Therefore, the life of the product equipped with such an optical pickup can be extended, and the reliability of the product can be further improved.

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.

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

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

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

Instead of using the collimator lens 16, for example, the first optical member 5 and the second optical member 11 may be provided with a function for converting the diffusion angle of light. In this case, since the collimator lens 16 does not need to be provided, accurate positioning is not required, and the number of components can be reduced to improve productivity.

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

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

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

At this time, the focal length L2 of the condenser lens 17 when reproducing the optical disk 19 is set to be longer than the focal length L1 of the condenser lens 17 when reproducing the optical disk 18. This difference in focal length is 1.0mm
In the following, preferably, the thickness is set to 0.6 mm or less, and when reproducing a plurality of discs of different types, there is almost no need to largely drive the actuator holding the condenser lens 17. Therefore, it is preferable because the focus position can be easily adjusted, and accordingly, the difference in the thickness of the substrate can be coped with very well.

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

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

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

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

Next, a case where the optical disk 19 is reproduced will be described. The reflected light from the optical disk 19 follows the same optical path as the outward path, is reflected by the optical path dividing means 15, is converted by the quarter-wave plate 14 from circularly polarized light to linearly polarized light orthogonal to the first polarization direction, The light enters the optical path splitting means 12 formed on the first slope 11 a of the optical member 11.
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 light reflected by the reflection means 13 forms a focus error signal while forming the focus error signal.
A signal corresponding to the data focused on 0 and recorded on the optical disc 19, a track error signal and a focus error signal are detected.

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

FIG. 2 is a diagram showing a relationship between a light emitting point and a collimator lens in the infinite optical system according to the first embodiment of the present invention. In FIG. 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. FIG. 3 shows the relationship between the amount of wavefront aberration and L3, L4 in the first embodiment of the present invention. That is, L3
When the ratio of L4 and L4 is changed, the amount of wavefront aberration generated at the time of incidence of the condenser lens is shifted by 500 μm in the tracking direction of the condenser lens 17 (solid line) and when there is no shift in the tracking direction. It is a comparison. Generally, the focusing lens during reproduction of the optical disc may shift up to about 500 μm in the tracking direction, and the amount of wavefront aberration allowed for effectively converging the light incident on the focusing lens on the optical disc is an RMS value. Considering that the light emission point 9a is not more than 0.07λ (where λ indicates the wavelength of light), the light emission point 9a where the amount of generation of aberration is relatively large and the condition for light incidence on the condenser lens 17 is tight is considered. If the amount of wavefront aberration is 0.07λ or less when the shift amount of the condenser lens 17 is maximum (500 μm) with respect to the light from It is considered that the light is converged on the optical disk regardless of the shift amount of the condenser lens 17. As a range satisfying this condition, as is apparent from FIG.
Ratio of 3 to L4 (L4 ÷ L3 = H, hereinafter expressed as H)
Is preferably 0.50 <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
0.53 <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 in 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.

Accordingly, since only one condenser lens 17 is required, it is possible to reduce the number of condenser lenses and to eliminate the necessity of providing a switching means for 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 this 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 Hereinafter, Embodiment 2 of the present invention will be described with reference to the drawings.

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

In FIG. 5, reference numeral 20 denotes a package. The package 20 includes a light source 2 for emitting light for the optical disk 18, a light source 9 for emitting light for the low-density optical disk 19, and a light source for mounting the light source 2 and the light source 9. The substrate part 20a on which the light receiving element 21 and the like for receiving the light reflected by the mounting part 34, the optical disk 18 and the low-density optical disk 19 are mounted, and the side wall part 20b provided so as to include those members.
And the like. Except for the size of the substrate portion 20a, the side wall portion 20b, and the terminal 20c constituting the package 20, the substrate portion 1a,
It has the same configuration as the side wall portion 1b and the terminal 1c.

Next, the light source 2 and the light source 9 mounted on the light source mounting portion 34 will be described. Also in the present embodiment, the sizes of the light source 2 and the light source 9 are different. In particular, when the light source 2 and the light source 9 are mounted on the same light source mounting portion 34 as in the present embodiment, it is not possible to improve the heat radiation property by using different materials for the light source mounting portion. Therefore, the difference in the size of the light source is a very important factor in determining the temperature of the light source during operation.

Also in this embodiment, the size of the light source 2 and the light source 9, specifically, the area where the light source 2 is in contact with the light source mounting portion 34 and the area where the light source 9 is in contact with the light source mounting portion 34 And different. The heat generated by the light sources 2 and 9 is released to the light source mounting portion 34 by conduction. For example, if the output of the light source 2 is larger than the output of the light source 9, If the contact area with the part 34 is made larger than the contact area of the light source 9 with the light source mounting part 34,
More heat can be released from the light source 2 to the light source mounting portion 34 per unit time. As a result, a large difference between the temperature during operation of the light source 2 and the temperature during operation of the light source 9 can be suppressed, so that the occurrence of inconvenience due to the temperature difference can be suppressed and the life of the product can be extended. This is preferable because the reliability can be improved and the reliability can be improved.

It is also effective to make the surface areas of the light source 2 and the light source 9 different. Generally, radiation (radiation) is a form of heat propagation in addition to the above-described conduction. Since the amount of radiant heat per unit time / unit area depends on the temperature, the amount of radiant heat at the same temperature increases as the surface area increases.

Therefore, if the output of the light source 2 is larger than the light source 9, the amount of radiant heat from the light source 2 is made smaller than the amount of radiant heat from the light source 9 by making the surface area of the light source 2 larger than the surface area of the light source 9. The temperature difference between the light source 2 and the light source 9 during operation can be reduced.
Therefore, it is preferable because it is possible to suppress the occurrence of the above-described inconvenience, to prolong the service life of the product, and to improve the reliability.

As described above, in an optical head having a plurality of light sources, the amount of heat radiation from the light sources can be made different by changing the size of the light sources according to the output of each light source. Therefore, the temperature difference during operation of each light source can be suppressed to a minimum, the oscillation wavelength shifts due to the temperature change of the light source, and the optical characteristics deteriorate with it, and the light source deteriorates / destroys due to high temperature, that is, the short life of the light source It is possible to suppress the occurrence of inconveniences such as conversion. Therefore, the life of a product equipped with such an optical head can be extended, and the reliability of the product can be further improved.

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 2a of the light source 2 is emitted from a position farther than it looks. To change the optical path as
It has the function of shifting the light emitting point 2e substantially in the direction opposite to the recording medium and lengthening the optical path length from the light source to the recording medium. The diffusion angle conversion means 23 is preferably formed of a diffraction grating, especially a hologram, because it can transmit light with high efficiency. Especially as a hologram, 4
It is preferable to use one having a stepped cross section or a saw-tooth cross section having more than a step because light can be used with high efficiency and a decrease in the amount of light can be prevented.

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

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

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

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

Reference numeral 27 denotes a diffusion angle conversion means. The diffusion angle conversion means 27 is provided on the light source side end surface 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 fluxes 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 slope 22c of the first substrate 22d.
The function is to change the diffusion angle of light in the diffusion direction to the convergence direction and to reflect the light beam in the convergence direction as it is.

The diffusion angle conversion means 31 is preferably formed of a diffraction grating, particularly 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 beam 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 is a light receiving means. The light receiving means 33 is a part of the light emitted from the light source 2 which is reflected without passing through the filter 24 and the light emitted from the light source 9 which is not reflected by the filter 24. The output of the light source 2 and the light source 9 is controlled by receiving the light transmitted through the light source 2 and feeding back the signal to the power 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 such as a hologram having a high angle dependency is formed in the first substrate 22d, the tolerance due to the angle increases unless the alignment is performed with considerably high accuracy, and the characteristics of light traveling toward the recording medium deteriorate. The possibility of doing it is very large. This undesirably leads to deterioration of signal characteristics and, as a result, causes the performance of the optical pickup device to deteriorate. Therefore, in the present embodiment, the diffusion angle conversion 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 and 27 are arranged to be substantially perpendicular to the optical axis of the light emitted from the light source 9.

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

It is preferable that 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 the present 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 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.
Can be reduced, and the optical path length after exiting the optical member 22 can be reduced as compared with the case where the optical pickup is guided without reflection, so that the optical pickup can be reduced in size and thickness.

Further, the light from the light source 2 and the light from the light source 9 are made incident on the optical member 22 on which a plurality of optical elements are formed and guided to a predetermined optical path. It is possible to accurately guide 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 positioning of the members can be simplified.

Further, in the present 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 configuration, 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.

Accordingly, 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 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 equal. In such a relationship, the light source 2 and the light source 9
By arranging the light source 2 and the light source 9, for example, the light source 2 and the light source 9 can be fixed to the same parallel plane member, and 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.

Further, in the present embodiment, the light source 2 and the light source 9 are arranged on the light source mounting portion. With the configuration in which a plurality of light sources are provided on the same light source mounting portion 34, the light sources 2 and the light sources 9 can be fixed in a predetermined positional relationship with respect to the light source mounting portion 34 in advance. Therefore, when assembling the optical head, the optical member 22
The positioning between the light source 2 and the light source 9 can be easily and accurately performed, and the productivity of the optical head can be improved. In addition, since the displacement between the light source 2 and the light source 9 and the optical member 22 is less likely to occur, an optical pickup having excellent optical characteristics can be obtained.

Further, by providing the light source 2 and the light source 9 on the same surface of the light source mounting portion 34, the light source 2 and the light source 9 can be more easily attached to the light source mounting portion 34. As compared with the above, the connection between the light source 2 and the light source 9 of the wire used for connecting the light source 2 and the light source 9 to an electrode for supplying power to the light source and the ground can be easily performed. Further, relative positioning between the light source 2 and the light source 9 can be performed more easily and accurately.

Further, the surface of the light source mounting portion on which the light source is mounted needs to be exposed with extremely high accuracy. However, by providing a plurality of light sources on the same surface, the surface to be exposed can be reduced to one surface. As a result, the number of manufacturing steps can be reduced, thereby improving the productivity and reducing the production cost.

The operation of the optical pickup having the above configuration will be described. When the recording medium is the optical disk 18, the 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 has its diffusion angle reduced by the diffusion angle conversion means 23.
That is, the spread of light is reduced.

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

Further, 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 is almost transmitted through the filter 24 and almost also transmitted 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 optical disk 18.

The light reflected back from the optical disk 18 is again incident on the quarter-wave plate 26, and when passing therethrough, is linearly polarized light orthogonal to the polarization direction when the light source 2 is emitted from the light source 2 from circularly polarized light. And is incident on the polarization splitting film 25. Unlike here, the polarization direction is now different, so that the light is reflected by the polarization separation film 25 and is reflected by the reflection units 29 and 3.
The light enters the diffusion angle conversion means 31 through 0. The light incident by the diffusion angle conversion means 31 is reflected without being diffracted, and a light beam of a predetermined shape is formed at a predetermined position on the light receiving element 21 by the signal forming means 32. Based on the incident light, both an RF signal and a focus / tracking signal are formed, thereby reproducing information and performing optimal control of the optical pickup.

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

The light converted into the convergent light by the diffusion angle conversion means 27 is almost reflected by the filter 24 and almost passes through the polarization separation film 25 provided thereafter, and enters the quarter-wave 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 back from the low-density optical disk 19 is again incident on 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 when a plurality of light sources are arranged in the same package, the wavefront aberration generated in the light emitted from each light source often differs greatly as in the first embodiment. Since the distance between the light emitting points 2a and 9a of the light sources 2 and 9 and the collimator 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 collimator 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 shows the relationship between the amount of wavefront aberration and L5, L6 according to the second embodiment of the present invention. That is, L
When the ratio of 5 to L6 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 (solid line), and when there is no shift in the tracking direction. This is what is being compared. Generally, the condensing lens 17 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 17 on the optical disc is: R
Considering that the MS 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 conditions for light incidence on the condenser lens 17 are tight. When the shift amount of the condenser lens 17 is maximum (500 μm) with respect to the light from the light emitting point 9a, the wavefront aberration amount is 0.07.
If it is equal to or smaller than λ, it is considered that the light incident on the condenser lens 17 from both light emitting points is converged on the optical disk regardless of the shift amount of the condenser lens 17.
As a range that satisfies this condition, as is clear from FIG. 7, it is preferable that the ratio of L5 and L6 (L6 ÷ L5 = H, hereinafter represented by H) is 0.50 <H <0.75. You can see that.

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 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 is clear from FIG. 3, the range satisfying this condition is the ratio (H) of L5 and L6.
0.53 <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 in 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 17 and to provide no means for switching the condenser lenses 17, thereby reducing the size of the optical pickup and the number of parts. It is possible to improve the productivity by reducing the number of components, to improve the reliability of the optical pickup by eliminating a complicated mechanism, to improve the operation speed, and the like.

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

Embodiment 3 Hereinafter, Embodiment 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.

8 and 9, reference numeral 40 denotes a package. The package 40 is a light source 2 for emitting light for the optical disk 18, a light source 9 for emitting light for the low-density optical disk 19, the optical disk 18, and the low-density optical disk 19. The light receiving means 58, 59 and the like for receiving the light reflected by the substrate 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. The substrate 40a, the side wall 40b, and the terminal 40c that constitute the package 40 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.

The light source 2 and the light source 9 are described in the first embodiment.
Also, the second embodiment has substantially the same configuration as that described in the second embodiment, and a description thereof will not be repeated.

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

The material forming the light source mounting portion 42 has a linear expansion coefficient of that of the light sources 2 and 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 equal or close to each other, the light source 2
In addition, since the occurrence of distortion between the light source 9 and the light source mounting portion 42 can be suppressed, the light source 2 and the light source 9 and the light source mounting portion 4 can be suppressed.
It is possible to prevent inconveniences such as the detachment of the light source 2 and the light source 2 and cracks in the light source 2 and the light source 9.

Further, since the heat generated by the light sources 2 and 9 can be efficiently released to the outside by setting the thermal conductivity of the light source mounting portion 42 as large as possible, the temperature of the light sources 2 and 9 rises. The wavelength of the light emitted from the light source 2 and the light source 9 is shifted, the convergence position of the light on the recording medium is slightly different, and many noise components are mixed in the reproduced signal, And the output of the light source 9 is reduced, so that the recording / reproducing operation on the recording medium cannot be performed normally, the life of the light source 2 and the light source 9 is shortened, and in the worst case, the light source 2 and the light source 9 are broken. It is possible to prevent the occurrence of inconvenience such as being performed.

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

Reference numeral 41 denotes a first optical member.
Has a function of guiding the light emitted from the light source 2 and the light source 9 to a predetermined optical path and guiding the light reflected by the optical disk and returned to the predetermined optical path. First optical member 41
Has a first slope 41a and a second slope 41b, and 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.

The following describes various optical elements present in the first optical member 41. 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 from each other. However, the reflection film 43 and the reflection film 44 may be formed on almost the entire first slope 41a as one large reflection film. In this case, the process of forming the reflective film using the mask can be omitted and the mask for forming the reflective film can be omitted, so that the productivity can be improved and the manufacturing cost can be reduced. Can be.

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

The polarization separating films 45 and 46 can guide the amount of light passing through to the recording medium without substantially reducing the amount thereof, so that the light use efficiency can be improved, and the light source 2 and the light source 9 can be improved. Is preferable because 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 a polarization separation film using a mask can be omitted, and a mask for forming the polarization separation films 45 and 46 can be omitted, so that productivity can be improved and manufacturing can be performed. Cost can also be reduced.

Further, in this embodiment, the polarization separation film is used as the separation means for the emitted light and the return light, but these may be separated by using a separation means such as a half mirror according to the required surface light quantity. Is also good.

Next, the second optical member 47 will be described.
The second optical member 47 is provided on the upper surface of the first optical member 41, and is joined to the first optical member 41 with an ultraviolet curing resin, an epoxy resin, or the like. Second optical member 47
Are formed of substantially parallel flat plates whose opposing surfaces are substantially parallel to each other, and a diffusion angle conversion unit 48 is formed on one end face through which light from the light source 9 is transmitted.

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

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

The third optical member 49 guides the light emitted from the light 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.

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

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

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

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

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

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

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

Numeral 52 denotes 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 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 the present 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 optical path splitting means 54 has a function of transmitting or reflecting the light emitted from the light source 2 and reflected by the optical disk 18 and returned.
It has a function of transmitting or reflecting light emitted from the light source 9 and reflected by the low-density optical disk 19 and returned. Here, it is preferable to use a half mirror so that the amount of light transmitted and the amount of light reflected by both the optical path dividing means 54 and the optical path dividing means 55 are substantially the same.

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

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

Further, it is preferable that the light sources 2, 9 and the light receiving means 58, 59, the optical members 41, 47, 49, etc. exist in a closed space as in the first embodiment.

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

In addition, since it is not necessary to adjust the position of each optical element with respect to each light source, the productivity is greatly improved. Further, since the mounting error of each optical element can be suppressed to the minimum, a good optical Characteristics can be realized.

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

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 from the light source 9 are made incident on the optical members 41, 47, and 49 on which a plurality of optical elements are formed, and guided to a predetermined optical path. Both light can be accurately guided to each recording medium, and there is no need to form multiple optical systems corresponding to multiple light sources using different optical members, thus improving productivity by reducing the number of parts. In addition, it is possible to simplify the positioning of each component member.

In this 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 this 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 configuration, 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 a portion where 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 the 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. In the present embodiment, the distances from the surface 41c of the first optical member 41 facing the light source to the light sources 2 and 9 are equalized. 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.

Further, in the present embodiment, the light source 2 and the light source 9 are arranged on the light source mounting portion. Since the plurality of light sources are provided on the same light source mounting portion in this manner, the light source 2 and the light source 9 can be fixed in a predetermined positional relationship with respect to the light source mounting portion 42. When assembling the optical head, the first optical member 41
The positioning between the light source 2 and the light source 9 can be easily and accurately performed, and the productivity of the optical head can be improved. In addition, since displacement between the light source 2 and the light source 9 and the first optical member 41 hardly occurs, an optical pickup having excellent optical characteristics can be obtained.

Further, by providing the light source 2 and the light source 9 on the same surface 42a of the light source mounting portion 42, the light source 2 and the light source 9 can be easily attached to the light source mounting portion 42, and provided on different surfaces. As compared with the case, the connection between the light source 2 and the light source 9 of the wire used for connecting the light source 2 and the light source 9 to the electrode or the ground for supplying power to the light source can be easily performed. Further, relative positioning between the light source 2 and the light source 9 can be performed more easily and accurately.

The surface of the light source mounting portion 42 on which the light source is mounted needs to be exposed with extremely high accuracy. However, by providing a plurality of light sources on the same surface, the surface on which the surface is exposed can be exposed. As a result, the number of manufacturing steps can be reduced, thereby improving the productivity and reducing the production cost.

The operation of the optical pickup having the above configuration will be described. When the recording medium is the optical disk 18, the 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 the polarization separation film 45 formed on the second slope 41b. Incident on. Since the polarization separation film 45 has a function of reflecting linearly polarized light emitted from the light source 2 and transmitting light in a polarization direction orthogonal to the light, the light incident from the light source 2 is reflected.

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

After that, the light emitted from the light source 2 passes through the collimator lens 16 when it is provided with a collimator lens and is converted into substantially parallel light. Converge to 18.

The light reflected back from the optical disk 18 returns to the quarter-wave plate 52. This light
Since the rotation direction of the elliptically polarized light when reflected by the optical disk 18 is opposite to that at the time of incidence, when the light passes through the quarter-wave plate 52, the rotation direction when the light source 2 is emitted from the elliptically polarized light is The light is converted into linearly polarized light substantially orthogonal to the polarization direction. 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 having passed through the quarter-wave plate 52 is incident on 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 inclined surface 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.

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

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

When the recording medium is the low-density optical disk 19, recording or reproduction is performed using 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.

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

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

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

After that, the light emitted from the light source 9 passes through the collimator lens 16 when it is provided with a collimator lens, and is converted into substantially parallel light. It converges on the density optical disc 19.

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

The light having passed through the quarter-wave plate 52 is incident on the third optical member 49 and is almost reflected by the filter 51 formed on the second slope 49b.
The light enters the multiple beam forming means 50 which is also received by 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.

Then, 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 in a light receiving portion formed at a predetermined position of the light receiving means 59 provided on the lower surface of the fourth optical member as it is, and is used for signal formation according to the purpose.

The light reflected by the optical path splitting 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 aberrations generated in the light emitted from the respective light sources often differ greatly as in the second embodiment. The distances between the light emitting points 2a and 9a (9e) of the light sources 2 and 9 and the collimator 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 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.

Furthermore, 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.

Although the light source 2 and the light source 9 are arranged substantially perpendicular to the surface of the recording medium in this embodiment,
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 Embodiment 4 of the present invention will be described below with reference to the drawings.

FIG. 10 is a sectional view of an integrated optical head according to the fourth embodiment of the present invention, and FIG. 11 is a detailed sectional view of an optical part according to the fourth embodiment of the present invention. 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 the board part 70a, the side wall part 70b, and the terminal 70c, which are its components, the board part 40a,
Since it has basically the same configuration as the side wall portion 40b and the terminal 40c, the description will be omitted except for the portions that are significantly changed.

The configurations of the light source 2 and the light source 9 are also substantially the same as those of the first and second embodiments, and the description is omitted here.

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

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

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

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 separating films 75 and 76 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 7
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 polarization separation film 7 is
Since the process for forming the polarization separation films 75 and 76 can be omitted and the number of masks for forming the polarization separation films 75 and 76 can be reduced, the productivity can be improved and the manufacturing cost can be reduced. .

Further, in this embodiment, the polarized light separating film is used as the separating means for the emitted light and the returning light, but these may be separated by using a separating means such as a half mirror according to the required surface light quantity. Is also good.

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

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

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

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

Finally, optical path dividing means 83 and 84 are formed on the third inclined surface 72c. This optical path dividing means has substantially the same configuration and function as the optical path dividing means 54 and 55 formed on the first inclined surface 53a of the fourth optical member 53 shown in the third embodiment. Here, the description is omitted.

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

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

[0230] Here, it is preferable to use a material such as resin and glass which has good translucency and does not decrease the light use efficiency, as a material constituting the shield member 85.

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 a good translucency such as glass or resin having a parallel plane shape, and is provided in an area where the light from the light source 9 passes through the end surface 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 configuration of the second substrate 86b is basically the same as that of the third optical member 49 shown in the third embodiment. The first substrate 86b has a first inclined surface 86d, a second inclined surface 86e, and a second inclined surface 86e.
The polarization separation film 88a, the beam separation unit 88b, the multiple beam forming means 88, and the filter 89 are respectively a first slope 49a and a second slope 49 of the third optical member 49 of the third embodiment.
b, the polarization splitting film 50a, the beam splitting section 50b, the multiple beam forming means 50, and the filter 51, which have substantially the same configuration, and thus detailed description is omitted here.

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

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

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.

Reference numeral 90 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 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 the present embodiment, or may be formed as a thin film.

Reference numerals 91 and 92 denote light receiving means. The light receiving means 91 receives the light transmitted through the light path dividing means 83 and the light reflected by the reflection 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 having a plurality of optical elements formed thereon and guided to a predetermined optical path, each of the related arts has been described. 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 first and second optical members 72 and 86 and is guided to a predetermined optical path, so that the entire package 70 is obtained. 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 optical pickup is guided without reflection, so that the optical pickup can be reduced in size and thickness.

Also, the light from the light source 2 and the light source 9 is incident on the first and second optical members 72 and 86 on which a plurality of optical elements are formed, and is guided to a predetermined optical path.
Both the light for the light 8 and the light for the low-density optical disk 19 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, respectively. It is possible to improve the productivity by reducing the number of parts and to simplify the positioning of each component.

In this 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 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. That is, since a plurality of light sources can be positioned with reference to one surface 72c, 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 a portion where light from each light source is incident, as in the case of the first optical member 72, the light is incident on 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.

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. In the present embodiment, the distance from the surface 72d of the first optical member 72 facing the light source to the light sources 2 and 9 is 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.

Further, in this embodiment, the light source 2 and the light source 9 are arranged on the light source mounting portion 71. With the configuration in which a plurality of light sources are provided on the same light source mounting portion 71 in this manner, the light source 2 and the light source 9 can be fixed in a predetermined positional relationship with respect to the light source mounting portion 71. Therefore, when assembling the optical head, the positioning between the first optical member 72 and the light source 2 and the light source 9 can be easily and accurately performed, and the productivity of the optical head is improved. Can be. In addition, since the displacement between the light source 2 and the light source 9 and the first optical member 72 hardly occurs, an optical pickup having excellent optical characteristics can be obtained.

Further, by providing the light source 2 and the light source 9 on the same surface 71a of the light source mounting portion 71, the light source 2 and the light source 9 can be more easily attached to the light source mounting portion 71, and provided on different surfaces. As compared with the case, the connection between the light source 2 and the light source 9 of the wire used for connecting the light source 2 and the light source 9 to the electrode or the ground for supplying power to the light source can be easily performed. Further, relative positioning between the light source 2 and the light source 9 can be performed more easily and accurately.

The surface of the light source mounting portion on which the light source is mounted needs to be exposed with very high accuracy. However, by providing a plurality of light sources on the same surface, the surface to be exposed can be reduced to one surface. As a result, the number of manufacturing steps can be reduced, thereby improving the productivity and reducing the production cost.

The operation of the optical pickup having the above configuration will be described. When the recording medium is the optical disk 18, the 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 72a of the first optical member 72, and the polarization separation film 75 formed on the second slope 72b. Incident on. Since the polarization separation film 75 has a function of reflecting linearly polarized light emitted from the light source 2 and transmitting light in a polarization direction orthogonal to the light, the light incident from the light source 2 is reflected.

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

After that, the light emitted from the light source 2 passes through the collimator lens 16 if it is provided with a collimator lens and is converted into substantially parallel light. Converge to 18.

The light reflected by the optical disk 18 and returned returns to the quarter-wave plate 90 again. This light
Since the rotation direction of the elliptically polarized light when reflected by the optical disk 18 is opposite to that at the time of incidence, when passing through the １ ／ wavelength plate 90, the rotation direction of the elliptically polarized light from the light source 2 The light is converted into linearly polarized light substantially orthogonal to the polarization direction of the light. 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 having passed through the 波長 wavelength plate 90 is incident on the second optical member 86, and is incident on 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.

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

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

The light reflected by the optical path dividing 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. Converge to 18.

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

The light that has passed through the 波長 wavelength plate 90 enters the second optical member 86, is almost reflected by the filter 89 formed on the second inclined surface 86e of the second substrate 86b, and is reflected by the first optical member 86. 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 diffusion light by the diffusion angle conversion means 87 has its diffusion angle converted and becomes convergent light, exits from the second optical member 86, passes through the shield member 85, and The light enters the optical member 72.

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 first optical member 72 as it is, and is used for signal formation according to the purpose.

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

Even in the case where a plurality of light sources are arranged in the same package, the wavefront aberrations generated in the light emitted from the respective light sources often differ greatly as in the second embodiment. The distances between the light emitting points 2a and 9a of the light sources 2 and 9 and the collimator lens are optimized, however, the concept is as described in the first and second embodiments.
Therefore, 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 71a of the light source mounting portion 71 at substantially the same height from the bottom surface of the light source mounting portion 71. 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 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 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.

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 Embodiments 1-4, the light source having a wavelength of about 650 nm and the light source of a wavelength of about 780 nm are used in combination. However, the present invention is not limited to this. And 650 may be used in combination.
A light source having a wavelength of about 50 nm and a light source having a wavelength of about 530 nm may be combined, or three or more light sources having different wavelengths may be used in combination.

(Embodiment 5) FIG. 12 shows an optical pickup module according to the present invention. In FIG. 12, 1
Reference numeral 01 denotes a disk, and in the present embodiment, disk 1
As 01, 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) is used. Here, the high-density disk 18 is, 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.

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

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

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

Reference numeral 105 denotes a module base on which the spindle motor unit 102, the optical pickup unit 103, and the feed unit 104 are mounted.

Reference numerals 106 and 107 denote spindle motors.
And a flexible substrate for supplying 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 the predetermined position, the actuator 10 provided in the optical pickup unit 103
8, the focusing signal and the tracking signal are detected, and the position is finely adjusted. Then, the reproduction signal of a predetermined track is detected by the light receiving means provided in the optical pickup unit 103 to reproduce the signal. .

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

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

[0291]

As described above, according to the present invention, in an optical head or an optical pickup provided with a plurality of light sources, the size of the light source is varied by changing the size of the light source according to the output of each light source. The amount of heat radiation can be made different, minimizing the temperature difference during operation of each light source. Of the light source, that is, shortening of the life of the light source can be suppressed. Therefore, the life of the product equipped with such an optical pickup can be extended, and the reliability of the product can be further improved. In particular, it is particularly effective to make the contact area between the light source and the light source mounting portion different so that the amount of heat conduction differs for each light source, or to make the surface area of the light source different so that the amount of radiant heat differs for each light source.

[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 collimator 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 collimator lens in an infinite optical system according to a second embodiment of the present invention.

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

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

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

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

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st package 1a Substrate part 1b Side wall part 1c Terminal 1d Emission part 2 Light source 3 Light receiving element 5 First optical member 5a First inclined surface 5b Second inclined surface 6 Optical path dividing means 7 Reflecting means 8 Second package 8a Substrate Part 8b side wall part 8c terminal 8d emission part 9 light source 10 light receiving element 11 second optical member 11a first inclined surface 11b second inclined surface 12 optical path dividing means 13 reflecting means 14 1/4 wavelength plate 15 optical path dividing means 16 collimator lens 17 Condenser lens 18 High-density optical disk 19 Low-density optical disk 20 Package 20a Substrate 20b Side wall 20c Terminal 21 Light receiving element 22 Optical member 22a First slope 22b Second slope 22c Third slope 22d First substrate 22e Second substrate 23 Diffusion angle conversion hologram 24 Filter 25 Polarization separation film 26 1/4 wavelength 27 Diffusion angle converting means 28 Multiple beam forming means 29 Reflecting means 30 Reflecting means 31 Diffusion angle converting means 32 Signal forming means 33 Light receiving element 34 Light source mounting part 34a Surface 34b surface 40 Package 40a Substrate 40b Side wall 40c Terminal 40d Opening 41 first optical member 41a first inclined surface 41b second inclined surface 41c surface 42 light source mounting portion 42a surface 43,44 reflection film 45,46 polarization separation film 47 second optical member 48 diffusion angle conversion means 49 third optical member 49a First slope 49b Second slope 50 Multiple beam forming means 50a Polarization separation film 50b Beam separation unit 51 Filter 52 1/4 wavelength plate 53 Fourth optical member 53a First slope 53b Second slope 54, 55 Optical path Dividing means 56, 57 Reflective film 58, 59 Light receiving means 70 Package 70a Substrate part 0b Side wall portion 70c Terminal 70d Opening 70h Power supply terminal 70i Power supply terminal 70j Ground terminal 71 Light source mounting portion 71a Surface 71b Light source mounting portion 71c Light source mounting portion 72 First optical member 72a First slope 72b Second Slope 72c Third slope 72d Surface 73, 74 Reflection film 75, 76 Polarization separation film 77, 78 Hologram 79, 80 Reflector 81, 82 Reflection film 83, 84 Optical path splitting means 85 Shielding member 86 Second optical member 86a First Substrate 86b Second substrate 86d First slope 86e Second slope 87 Diffusion angle conversion means 88 Multiple beam forming means 88a Polarization separation film 88b Beam separation unit 89 Filter 90 1/4 wavelength plate 91 Light receiving means 92 Light receiving means 101 Disk 102 Spindle motor section 103 Optical pickup section 104 Feed Unit 105 Module base 106, 107 Flexible board 108 Actuator

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Masaharu Fukakusa 1006 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd.

Claims (9)

[Claims] A first light source; a first light source mounting portion on which the first light source is mounted; and a first light source for receiving light emitted from the first light source and reflected by a recording medium. Light receiving means, a second light source, a second light source mounting portion for mounting the second light source, and a second light source for receiving light emitted from the second light source and reflected by the recording medium. An optical pickup comprising a light receiving means, wherein the first light source and the second light source have different volumes. 2. The method according to claim 1, wherein the first light source is formed to be larger than the second light source when the average output of the first light source is larger than the average output of the second light source. Item 1. An optical pickup according to item 1. 3. An area in which the first light source is in contact with the first light source mounting portion is larger than an area in which the second light source is in contact with the second light source mounting portion. The optical pickup according to claim 2, wherein 4. The optical pickup according to claim 2, wherein the surface area of the first light source is larger than the surface area of the second light source. 5. A first light source, a first light source mounting portion on which the first light source is mounted, and a first light source for receiving light emitted from the first light source and reflected by a recording medium. Light receiving means, a second light source, a second light source mounting portion on which the second light source is mounted, and a second light source for receiving light emitted from the second light source and reflected by the recording medium. Light receiving means, the first light source,
The second light source, the first light source mounting portion, and the second light source mounting portion;
A light source mounting portion, the first light receiving means, and a storage member for storing the second light receiving means, wherein the first light source and the second light source are different in size. Characteristic optical head. 6. The method according to claim 1, wherein the first light source is formed to be larger than the second light source when the average output of the first light source is larger than the average output of the second light source. Item 6. The optical head according to item 5, 7. An area in which the first light source is in contact with the first light source mounting portion is larger than an area in which the second light source is in contact with the second light source mounting portion. The optical head according to claim 6. 8. The optical head according to claim 6, wherein the surface area of the first light source is larger than the surface area of the second light source. 9. The optical head according to claim 5, wherein the first light source and the second light source are formed on the same light source mounting portion.