JP2001034996A - Optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely correct aberration with a simple configuration without increasing a component for correcting aberration and miniaturize a pickup and improve productivity by controlling the aberration of the emission luminous flux of a condensation means for condensing incidence light at a record medium only by an aberration correction means. SOLUTION: Emission light 96 of an emission point 9a of a light source 9 passes through an optical path division means 12 of a first inclined surface 11a of a second optical member 11, is reflected by an optical path division means 15, and then is converted to a luminous flux 9c by a collimator lens 16. Then, the wave front of transmission light is controlled by an aberration correction means 307, and coma aberration being generated by disk tilt is corrected, thus correcting the wave front of transmission light in advance. DC polarization whose wave front has been adjusted is applied to a 1/4 wavelength plate 308. In this case, a voltage is applied to it and optical anisotropy is generated in the direction of an electric field when viewed from an incidence side by the generated electric field. In this case, the 1/4 wavelength plate 308 is arranged and controlled so that it is inclined by 45 degrees for the DC polarization as circular polarization, and luminous flux 9d is condensed at a low-density optical disk 19 by a condensation lens 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical pickup for recording and reproducing information on an optical disk.

[0002]

2. Description of the Related Art At present, a relatively high-density recording medium such as a DVD (Digital Video Disc),
There are recording media of relatively low density such as CDs (compact discs), and there are also recording media (such as CD-Rs) in which the wavelength of light that can be read is limited. In such a background, the optical pickup device is
In order to be able to effectively use the assets of software published to date, it is required that not only high-density optical disks but also low-density optical disks and optical disks with high wavelength dependence can be reproduced. However, if an optical system designed for a high-density optical disk is used as it is for a conventional optical disk, a large spherical aberration occurs due to a difference in the thickness of the disk substrate, an image spot is blurred, and information cannot be reproduced. If the wavelength of the light source is different from the predetermined value, there is a problem that an optical recording medium having a high wavelength dependency cannot be reproduced. Therefore, in order to solve this problem, an optical pickup equipped with a plurality of light sources is currently being put to practical use.

As another problem, there is a problem of a disc tilt due to a warp of the optical disc itself, a tilt of the optical disc due to a low precision at the time of mounting, and the like. When disc tilt is present, the value of what is called coma among the optical aberrations increases, and the light incident on the optical disc is not properly focused on the recording surface or the light reflected on the optical disc is received. It is more likely that the light will not be collected by the light receiving means that converts the light into electric signals. Various methods have been proposed to solve the disk tilt problem. Among them, the use of an aberration correction liquid crystal that controls the wavefront of light using a liquid crystal and corrects aberrations enables a tilt in the tangential direction. However, since the tilt in the radial direction can be accurately corrected, particularly excellent tilt correction characteristics can be obtained.

An example in which the optical pickup having a plurality of light sources and the aberration correcting liquid crystal are used together will be described with reference to the drawings.

FIGS. 13 (a) and 13 (b) are schematic diagrams showing the structure of a conventional optical pickup. FIG. 13 (a) shows the traveling direction of light emitted from the first light source 200, and FIG. FIG. 2B particularly shows the traveling direction of the light emitted from the second light source 210.

First, the outward light of the light emitted from the first light source 200 will be described.

In FIG. 13A, light emitted from a light source 200 that emits light of wavelength λ1 is converted into parallel light by a collimator lens 201, and a part of the light passes through a beam splitter 202, Part of the light passes through the beam splitter 203 and enters the aberration correction liquid crystal 204. The aberration correcting liquid crystal 204 can control the wavefront of light passing therethrough by controlling the voltage applied between electrodes provided with the liquid crystal interposed therebetween. Therefore, by correcting the wavefront of the light passing therethrough in advance so as to cancel the coma generated by the tilt, the amount of the coma generated by the tilt can be suppressed to the minimum. The light whose wavefront has been adjusted by the aberration correction liquid crystal 204 is condensed by the objective lens 205 and enters the optical disc 206.

Next, the return route will be described.

A part of the light reflected by the optical disk 206 and having the information of the recording surface added thereto passes through the aberration correcting liquid crystal 204 and the beam splitter 203 and enters the beam splitter 202. And this beam splitter 20
Only the light reflected by 2 is condensed by the collimator lens 207 and enters the light receiving means 208, where an RF signal and a servo signal are formed.

Next, the outward path of the light emitted from the second light source 210 will be described.

In FIG. 13B, light emitted from a light source 210 for emitting light of wavelength λ2 is converted into parallel light by a collimator lens 211, and a part of the light passes through a beam splitter 212, Part of the light is reflected by the beam splitter 213 and enters the aberration correction liquid crystal 214. The aberration correction liquid crystal 214 can control the wavefront of the light passing therethrough by controlling the voltage applied between the electrodes provided with the liquid crystal interposed therebetween. Therefore, by correcting the wavefront of the light passing therethrough in advance so as to cancel the coma generated by the tilt, the amount of the coma generated by the tilt can be suppressed to the minimum. The light whose wavefront has been adjusted by the aberration correction liquid crystal 204 is condensed by an objective lens 205 and is incident on an optical disc 213 different from the above-described optical disc 206.

Next, the return route will be described.

A part of the light reflected by the optical disk 213 and having the information on the recording surface added passes through the aberration correcting liquid crystal 204. Thereafter, the light reflected by the beam splitter 203 enters the beam splitter 212. Then, only the light reflected by the beam splitter 212 is condensed by the collimator lens 214 and is incident on the light receiving means 215 to form an RF signal and a servo signal.

[0014]

However, in such an optical pickup, the light use efficiency is extremely low, and if it is necessary to secure the required amount of disk surface on each of the optical discs 206 and 213, each light source 200 and The output of the light emitted from 210 must be increased, which inevitably consumes a large amount of power and has a short product life.

In order to improve the light use efficiency, a commonly used method is to use each beam splitter 20.
It is conceivable to use 2,203,212 as a polarization separation type and use it together with a 波長 wavelength plate. However, the ４ wavelength plate needs to be separately provided for each wavelength and converts linearly polarized light into circularly polarized light. In view of this point, it is very difficult to use the aberration correcting liquid crystal together with the aberration correcting liquid crystal since linearly polarized light must be incident on the aberration correcting liquid crystal. Even if it is possible, an increase in the number of parts is inevitable, resulting in an increase in the size of the optical pickup and a decrease in productivity.

An object of the present invention is to provide a small-sized optical pickup capable of performing accurate tilt correction while improving light use efficiency and reducing power consumption. Aim.

[0017]

In order to solve the above-mentioned problem, a quarter-wave plate is disposed between the aberration correcting means and the recording medium.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a light source for emitting linearly polarized light, a light condensing means for condensing incident light on a recording medium, and an aberration of a light beam incident on the light condensing means. Correction means for correcting the aberration, and controlling the aberration of the luminous flux emitted from the light condensing means only by the aberration correction means, without increasing the number of constituent members for aberration correction, thereby achieving a simpler configuration. As a result, it is possible to reliably perform the aberration correction, so that it is possible to reduce the size of the optical pickup and improve the productivity.

According to a second aspect of the present invention, the aberration correction means includes a liquid crystal, and a first light-transmitting substrate and a second light-transmitting substrate sandwiching the liquid crystal, thereby utilizing light. The reduction in efficiency can be minimized, and the control of the wavefront can be performed according to the situation.

According to a third aspect of the present invention, a liquid crystal is formed by forming a first transparent electrode on a first light-transmitting substrate and forming a second transparent electrode on a second light-transmitting substrate. Since the voltage can be applied to the liquid crystal, the control of the liquid crystal can be performed more widely, and the decrease in the light use efficiency can be suppressed to a minimum.

According to a fourth aspect of the present invention, at least one of the first transparent electrode and the second transparent electrode is divided into at least two or more regions, so that the wavefront of the incident light is reduced. Correction can be performed more precisely in a wider range.

According to a fifth aspect of the present invention, there is provided a light receiving means for converting optical information from a recording medium into an electric signal, and a control means for controlling the operation of the aberration correcting means based on the information from the light receiving means. With this arrangement, it is possible to control the aberration correction unit according to the light receiving state of the light receiving unit.

According to a sixth aspect of the present invention, there is provided a light source for emitting linearly polarized light, and a １ ／ for converting the polarization state of the linearly polarized light.
A wave plate, a light condensing means for converging incident light on a recording medium, and an aberration correcting means for correcting aberration of a light beam incident on the light condensing means. Provided between the recording medium and the recording medium, the light incident on the aberration correcting means can be linearly polarized, so that the correction of the disc tilt by the aberration correcting means can be performed more reliably and the aberration can be corrected. A decrease in the amount of light in the correction means can be suppressed to a minimum.

According to a seventh aspect of the present invention, the aberration correction means includes a liquid crystal, and a first light-transmitting substrate and a second light-transmitting substrate sandwiching the liquid crystal. The reduction in efficiency can be minimized, and the control of the wavefront can be performed according to the situation.

According to the present invention, the first transparent electrode is formed on the first light-transmitting substrate, and the second transparent electrode is formed on the second light-transmitting substrate. Since the voltage can be applied to the liquid crystal, the control of the liquid crystal can be performed more widely, and the decrease in the light use efficiency can be suppressed to a minimum.

According to a ninth aspect of the present invention, at least one of the first transparent electrode and the second transparent electrode is divided into at least two or more regions, so that the wavefront of incident light can be reduced. Correction can be performed more precisely in a wider range.

According to a tenth aspect of the present invention, there is provided a light receiving means for converting optical information from a recording medium into an electric signal, and a control means for controlling the operation of the aberration correcting means based on the information from the light receiving means. With this arrangement, it is possible to control the aberration correction unit according to a change in the light receiving state of the light receiving unit.

According to an eleventh aspect of the present invention, since the quarter-wave plate is made of liquid crystal, even if the state of light changes,
The function as a quarter-wave plate can be reliably provided.

According to a twelfth aspect of the present invention, there is provided a light receiving means for converting optical information from a recording medium into an electric signal, and a control means for controlling the operation of the quarter-wave plate based on the information from the light receiving means. Is provided, the を wavelength plate can be controlled according to the light receiving condition of the light receiving means, so that the 確 実 wavelength plate can be reliably functioned as a 波長 wavelength plate.

According to a thirteenth aspect of the present invention, both the aberration correcting means and the quarter-wave plate are made of liquid crystal, so that the aberration correcting means can be used in accordance with the state of incident light and the amount of coma. The function of the quarter-wave plate can be optimized.

According to the fourteenth aspect of the present invention, since the aberration correcting means and the quarter-wave plate are integrated, it is possible to reduce the number of assembling and positioning steps accompanying the reduction in the number of parts. The productivity of the pickup can be improved. Further, even if the mounting position accuracy of the quarter-wave plate is lower than that in the case where a plurality of the quarter-wave plates are provided, the predetermined optical characteristics can be satisfied. Thus, an optical pickup having a high yield can be obtained.

According to a fifteenth aspect of the present invention, there is provided an integrated aberration correcting means and a quarter-wave plate, comprising a first substrate, a second substrate, and a third substrate. Providing a first liquid crystal serving as the aberration correction means between a substrate and a second substrate;
By providing the second liquid crystal serving as the 波長 wavelength plate between the second substrate and the third substrate, the configuration of the integrated aberration correction means and the 補正 wavelength plate can be simplified. .

According to a sixteenth aspect of the present invention, the first substrate,
Since each of the second substrate and the third substrate is formed of a light-transmitting material, a decrease in light use efficiency can be suppressed to a minimum.

[0034] The invention according to claim 17 is the first substrate,
The transparent electrodes are formed on the surfaces of the second substrate and the third substrate facing the first liquid crystal or the second liquid crystal, respectively, so that the liquid crystal forming the aberration correction means and the quarter-wave plate are formed. Since both of the liquid crystals can be directly sandwiched between the electrodes, the liquid crystal can be operated at a lower voltage, the liquid crystal can be controlled more widely, and the light use efficiency decreases. Can be minimized.

[0035] The invention according to claim 18 is the first substrate,
Since at least one of the transparent electrodes formed on the second substrate and the third substrate is a transparent electrode divided into at least two or more regions, the correction of the wavefront with respect to the incident light can be performed in a wider range. And can be performed more precisely.

The invention according to claim 19 is provided with a first control means for controlling the operation of the liquid crystal of the aberration correcting means and a second control means for controlling the operation of the liquid crystal of the quarter-wave plate. This makes it possible to reliably operate both the aberration correction unit and the quarter-wave plate with respect to incident light.

According to a twentieth aspect of the present invention, at least one of the first control means and the second control means operates based on information from a light receiving means for converting optical information from a recording medium into an electric signal. By doing so, control according to the state of the recording medium can be performed.

According to the twenty-first aspect of the present invention, the aberration of the light beam emitted from the light source is controlled only by the aberration correction means, so that a simpler configuration can be achieved without increasing the number of constituent members for aberration correction. Since reliable aberration correction can be performed, miniaturization of the optical pickup and improvement in productivity can be achieved.

According to a twenty-second aspect of the present invention, a first light source for emitting linearly polarized light, a second light source for emitting light having a wavelength different from the first light source, and a recording medium Condensing means for converging light, and aberration correcting means for correcting aberration of at least one of light emitted from the first light source and light flux emitted from the second light source incident on the light condensing means. With this arrangement, even when light having a plurality of different wavelengths passes, it is possible to provide an aberration correction function for at least light having one wavelength.

According to a twenty-sixth aspect of the present invention, at least one of the first transparent electrode and the second transparent electrode is provided with the first transparent electrode.
A first split electrode divided into a shape suitable for correcting aberration of light emitted from the light source, and a second split electrode divided into a shape suitable for correcting aberration of light emitted from the second light source. ,
Is formed, accurate aberration correction can be performed on both the light from the first light source and the light from the second light source.

According to a twenty-seventh aspect of the present invention, the first transparent electrode includes a first split electrode divided into a shape suitable for correcting aberration of light emitted from the first light source, and a second light source. A second split electrode divided into a shape suitable for correcting the aberration of the light emitted from the first light source. The second transparent electrode has a shape suitable for correcting the aberration of the light emitted from the first light source. A third divided electrode divided into a shape and a fourth divided electrode divided into a shape suitable for correcting aberration of light emitted from the second light source are formed, and the first light source is used. In the case, the potential difference between the second divided electrode and the fourth divided electrode is substantially 0, and when the second light source is used, the potential difference between the first divided electrode and the third divided electrode is reduced. Is substantially zero, the split electrode formed for the first light source is It is possible to suppress an adverse effect on the light from the source.

According to a thirtieth aspect of the present invention, there is provided a first light source that emits linearly polarized light, a second light source that emits light having a wavelength different from that of the first light source, and an emission source that emits light from the first light source.光 wavelength plate for converting the polarization state of at least one of the light emitted and the light emitted from the second light source,
Light collecting means for collecting incident light on a recording medium, and aberration correction means for correcting at least one of aberrations of light traveling from the first light source or the second light source toward the recording medium, The provision of the quarter-wave plate between the aberration corrector and the condensing unit allows the aberration corrector and the quarter-wave plate to be provided in at least one of the optical pickups provided with light having different wavelengths. In addition to being able to function with respect to light from a light source, a decrease in light use efficiency can be minimized.

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

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

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

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

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

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

It is preferable to use a monochromatic light source having good coherence, directivity, and light condensing properties, since a beam spot having an appropriate shape can be formed relatively easily, and 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.

Among them, AlGaAsP is a preferable material because it has stable performance for 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 a sufficient amount of light required 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 2 will be significantly reduced, and in the worst case, the light source 2 will be destroyed. For this reason, an electric circuit malfunctions, the light source 2 itself causes a wavelength fluctuation, the oscillation wavelength is shifted, and noise is mixed in a signal, so that the reliability of the optical pickup is greatly reduced. .

The first optical member 5 is joined to the opening 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
The optical path splitting means 6 composed of a polarization splitting film is formed on the inclined surface 5a, and the reflecting means 7 for guiding the incident light to the light receiving element 3 is formed on the second inclined surface 5b.

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 plane-parallel 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 focus / 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 the glasses, it is preferable to use an optical glass having a small wavelength dispersion, that is, a large Abbe number, such as BK-7, because the occurrence of chromatic aberration due to wavelength fluctuation can be particularly suppressed. In addition, among these optical glasses, BK-7 is low in cost, and is therefore most suitable as the material of the first optical member 5.

The first optical member 5 may be formed by joining a plurality of dice-shaped prisms in which optical elements are formed in advance linearly, 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 package 1 is directly inserted into the opening 1 d provided in the side wall 1 b 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, and a terminal 8c is further formed. In the following, the second package 8 will be referred to as the first package.
Will be described below.

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

Among the metallic materials, metallic materials such as Cu, Al and Fe having high thermal conductivity, FeNi alloy and FeN
It is preferable to use an alloy material such as an iCo alloy. This is because these materials are inexpensive, have high heat dissipation, and also have an effect as an electromagnetic shield that blocks noise such as electromagnetic waves from a high-frequency superimposing circuit or the like. Among these, in particular, Fe, FeNi alloy, and FeNiCo alloy have low thermal resistance and good heat dissipation, so that the heat generated by the light source 9 can be efficiently released to the outside. Since these materials are low in cost, it is possible to provide the optical pickup device at low cost.

When the oscillation wavelength of the light source 9 is 800 nm or less, the beam spot when the light emitted from the light source 9 converges on the recording medium can be easily adjusted to a size approximately equal to the pitch of the track formed on the recording medium. It is preferable because it can be used. 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
And the inside of a space surrounded by the second package 8 and the second optical member 11, that is, the light sources 2, 9 and the light receiving elements 3, 1
It is preferable that the space where 0 and the like are arranged is sealed. With such a configuration, it is possible to prevent impurities such as dust and moisture from entering the inside of the package, so that the performance of the light sources 2 and 9 and the light receiving elements 3 and 10 can be maintained and light can be emitted. Also, the deterioration of the optical characteristics of the light can be prevented. Further, an inert gas such as N ₂ gas, dry air or Ar gas is sealed in a space enclosed by the packages 1 and 8 and the optical members 5 and 11 so that the interior of the packages 1 and 8 is It is further preferable because the dew condensation occurs on the surfaces of the optical members 5 and 11 to deteriorate the optical characteristics, and the deterioration of the characteristics due to oxidation of the light sources 2 and 9 and the light receiving elements 3 and 10 can be prevented.

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.
Since it is possible to reduce the amount of light emitted from the optical pickup, the life of the light source 2 and the light source 9 can be extended, and the reliability of the optical disk device equipped with the optical pickup can be improved.

As the optical path splitting means 15 having the above-mentioned 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.

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.

Numeral 307 denotes an aberration correcting means.
Reference numeral 07 denotes a component that can control the wavefront of light passing therethrough, and various configurations are conceivable. Here, a component composed of a translucent substrate and liquid crystal is used.

Reference numeral 308 denotes a 波長 wavelength plate.
Reference numeral 08 has a function of converting light that has entered as linearly polarized light into elliptically polarized light. Convert to Here, in particular, the quarter-wave plate 3
08 is composed of liquid crystal sandwiched between translucent substrates.

Reference numeral 17 denotes a condensing lens. The condensing lens 17 condenses incident light to form a beam spot on the optical disk. The lens driving means (not shown) controls the focusing direction and the tracking direction. It is supported so that it can be moved. Since the amount of light incident on the condenser lens 17 can be increased by the collimator lens 16, the light use efficiency is improved. Therefore, light source 2,
9 can be used at an output much lower than the maximum output, the life of the light sources 2 and 9 can be prolonged, and the reliability of the optical pickup device can be improved.

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

Next, the aberration correcting means 30 will be described with reference to the drawings.
The configuration and operation of the 7 and 1/4 wavelength plates 308 will be described. FIG. 19 is a sectional view of the aberration correcting means and the quarter-wave plate according to an embodiment of the present invention. In FIG. 19, reference numeral 320 denotes a liquid crystal, and since the amount of twist of the liquid crystal 320 changes according to the applied voltage, the wavefront can be controlled according to a situation (for example, a change in the warpage of the disk).

The substrates 321 and 322 are substrates.
It is preferable that both materials 322 have a certain degree of hardness, such as glass, and use a material having a transmittance of about 90% or more with respect to the frequency of the incident light because a reduction in the amount of light can be suppressed. Such materials include BK
It is preferable to use -7, SF-11 or the like in terms of cost and productivity.

The substrates 321, 322 are provided with the liquid crystal 32.
Electrodes 321a and 322a for applying a voltage to 0 are formed. Here, the electrodes 321a and 322a are
It is preferable to form the liquid crystal on the side facing the liquid crystal 320 because the liquid crystal can be controlled with a lower voltage. In addition, it is preferable that both of the electrodes 321a and 322a are divided into a plurality of portions so that the wavefront can be corrected more accurately in a wider range. With such a configuration, finer aberration correction can be performed, and the optical characteristics of the optical pickup can be improved.

When the electrode 321a and the electrode 322a are separately provided, the shape of the divided electrode acting on the light emitted from the light source 2 and the shape of the divided electrode acting on the light emitted from the light source 9 are different. The configuration in which the shapes of the electrodes are different from each other so that the aberrations can be optimally corrected for the respective lights emitted from the light sources 2 and 9 is different from those of the light sources 2 and 9 which are irradiated with different recording media. It is preferable because the aberration correction that cancels out the aberration generated in each recording medium can be surely performed in advance with respect to the light from the recording medium.

As a method of making the shape of the divided electrodes different at this time, the way of connecting the feeder lines connected to the plurality of divided electrodes is changed for each of the light sources 2 and 9 so that the shape of the electrode to be fed is changed. And the first electrode and the second electrode optimized in advance for the light from the respective light sources 2 and 9 are formed on the electrode 321a in advance, and the respective light sources 2 and 9 are formed on the electrode 322a. The first electrode and the second electrode that are optimized for the light are formed, and when the power is supplied from the power supply 323 to the electrode 321a and the electrode 322a, the power is supplied to the first electrode or the second electrode. There is a method of switching power supply.

In particular, in the latter case, when the light source 2 is operating, the second electrode formed on the electrode 321a so as to optimally act on the light from the light source 9 and the electrode 32
The potential difference between the second electrode and the second electrode formed at 2a is almost zero.
It is preferable that the configuration is such that the light emitted from the light source 2 passing therethrough is not subjected to extra aberration and appropriate aberration correction can be performed. Conversely, when the light source 9 is operating, the first electrode formed on the electrode 321a and the first electrode formed on the electrode 322a operate optimally on the light from the light source 2. It is preferable that the potential difference be substantially zero. With such a configuration, a potential difference is generated between the electrodes that are not operating, an aberration that should not exist is generated, and deterioration of the signal characteristics of the optical pickup due to the aberration can be prevented.

A typical configuration of such a divided electrode will be described with reference to the drawings. FIG. 22 is a front view showing the electrode configuration of the aberration correction means according to one embodiment of the present invention.
2A and the arrangement of the divided electrodes formed on the electrode 322a. In the figure, electrode 321a and electrode 3
Each of the divided electrodes 22a has the same shape and arrangement as described below. The region A is a region through which the light beam from the light source 2 is transmitted, and the region B is a region through which the light beam from the light source 9 is transmitted. D1, D2, E1, and E2 are divided electrodes divided into optimal shapes for correcting the aberration of the light flux of the light source 9. When the light source 9 is used, D1, D2, E1, and E2 are used.
An optimum potential is applied between the counter electrode and each of the opposing electrodes (electrodes sandwiching the liquid crystal) to change the transmission refractive index, thereby controlling the phase of light and correcting aberration. On the other hand, when the light source 2 is used, the divided electrodes C1, D1, E1, C2, D2,
By applying a potential to E2, the aberration of the light beam of the light source 2 can be optimally corrected. At this time, by making the voltages applied to the divided electrodes C1, D1, E1, C2, D2, and E2 different from each other, it is possible to more precisely control the potential difference between the opposing electrodes (electrodes opposing the liquid crystal). This is preferable because it is possible to more ideally control the phase of light and correct aberrations.

It is to be noted that the larger the number of divided electrodes is, the more accurate aberration correction can be performed.

In the present embodiment, the split electrode optimized for light from the light source 2 and the split electrode optimized for light from the light source 9 are formed on each of the electrodes 321a and 322a. , A divided electrode optimized for light from the light source 2 is formed on the electrode 321a, and the light source 9 is formed on the electrode 322a.
The configuration may be such that a split electrode optimized for light from the light source is formed. For example, when correcting the aberration of the light from the light source 2, different potentials are respectively applied to the divided electrodes formed on the electrode 321a, and the divided electrodes formed on the opposing electrode 322a are set at substantially the same potential. Electrode 322a
The optimum potential difference is given between the two to change the transmission refractive index, thereby controlling the phase of the light from the light source 2 and correcting the aberration.

The power supply 323 applies a predetermined voltage to the electrodes 321a and 322a. By controlling this voltage, the wavefront of the passing light can be controlled.
Therefore, by correcting in advance the wavefront of the light passing therethrough so as to cancel the coma generated by the tilt,
It is possible to minimize the amount of aberration such as coma generated due to the tilt. When the electrodes are provided separately, the voltage applied to each electrode can be made different to control the wavefront of the passing light more finely, and the coma generated by the disc tilt can be reduced. It can be removed more efficiently.

Further, the aberration correction means 307
It is preferable to control the wavefront for the light emitted from any of the above. Therefore, it is necessary to change the control of the voltage applied between the liquid crystal electrodes depending on which of the light sources 2 and 9 the light is emitted. Therefore, control means (not shown) for controlling the power supply 323 for applying a voltage to the electrodes 321a and 322a of the aberration correction means 307
Power supply 32 based on the information of which one is emitting light.
3 is preferably controlled. Thereby, the light sources 2, 9
Optimum wavefront control can be performed for light from any of the above. Information on which of the light sources 2 and 9 is emitting light can be obtained by, for example, a control unit (not shown) of the light sources 2 and 9.
May be based on a signal from a disc determination unit (not shown) for detecting which type of optical disc is set, or may use other known methods. Good.

When the electrodes optimized for each of the light sources 2 and 9 are formed on the electrodes 321a and 322a, the configuration is such that the power supply 323 can control which electrode is supplied with power. ing.

As described above, in this embodiment, the aberration correction of the light emitted from the light sources 2 and 9 and applied to the recording medium is performed only by the aberration correction means 307 in each case. With such a configuration, reliable aberration correction can be performed with a simpler configuration without increasing the number of constituent members for aberration correction, which is preferable from the viewpoint of miniaturization and productivity of the optical pickup. .

Next, the 波長 wavelength plate 308 will be described.

In FIG. 19, reference numeral 324 denotes a liquid crystal.
In No. 4, the amount of twist changes in accordance with the applied voltage.

The substrates 325 and 326 are substrates.
Electrodes 325a and 326a for applying a voltage to the liquid crystal 324 are formed on the surface of the side 326 facing the liquid crystal 324. The electrodes 325a and 326a are preferably formed according to the diffusion angle of the incident light. That is, when the incident light is parallel light, it is undivided, the diffusion angle is large, and when the transmitted light has a long distance to pass through the liquid crystal 324, the amount of twist decreases as it goes to the periphery. It is preferable to divide the electrodes to optimize the applied voltage.

Reference numeral 327 denotes a power supply.
a, 326a is applied with a predetermined voltage. By controlling this voltage, the phase of light passing in a specific direction can be shifted by ４ wavelength, and the incoming linearly polarized light is converted into elliptically polarized light. can do.

Further, the 波長 wavelength plate sets the phase of light in a specific direction to 1 for light emitted from any of the light sources 2 and 9.
It is preferable to shift by / 4 wavelength. For this reason, depending on which of the light sources 2 and 9 the light is emitted from,
It is necessary to change the control of the voltage applied between the electrodes 325a and 326a. Therefore, a control means (not shown) for controlling the power supply 327 for applying a voltage to the electrodes 325a and 326a of the quarter-wave plate 308 uses a power supply 327 based on information on which of the light sources 2 and 9 is emitting light. Is preferably controlled. This makes it possible to perform optimal phase control for light from any of the light sources 2 and 9.
Information on which of the light sources 2 and 9 is emitting light is:
For example, control means (not shown) for the light sources 2 and 9 and the light sources 2 and 9
May be based on a signal from a light receiving unit that receives the light emitted from the optical disc, or may be based on a signal from a disc determination unit (not shown) that detects which type of optical disc is set, Other known methods may be used.

Thus, by optimally controlling the voltage applied to the liquid crystal according to the wavelength of the incident light, the light emitted from both of the light sources 2 and 9 can be accurately controlled. Since the phase can be shifted by １ ／ wavelength, any incident light can be reliably converted from the incident linearly polarized light into elliptically polarized light, and the light reflected from the optical disks 310 and 311 can be used as the original light. Can be reliably converted to linearly polarized light orthogonal to the linearly polarized light, and thus the utilization efficiency of any light emitted from the light sources 2 and 9 can be improved, so that the output of each of the light sources 2 and 9 is low. Since it can be used in a state, the power consumption can be reduced, the life of the light sources 2 and 9 can be extended, and the reliability of the optical pickup can be improved. .

When a plurality of light sources having different wavelengths of light are used in the related art, a quarter-wave plate, which had to be provided for each light source, can be combined into one, thereby reducing the number of parts. Since the number of assembling and positioning steps can be reduced, the productivity of the optical pickup can be improved. Further, even if the accuracy of the mounting position of the quarter-wave plate 308 is lower than that in the case where a plurality of the quarter-wave plates 308 are provided, the predetermined optical characteristics can be satisfied. Thus, an optical pickup having a high yield can be obtained.

The な お wavelength plate may be formed of a birefringent material optimized for light having a wavelength substantially intermediate between the wavelength of the light source 2 and the wavelength of the light source 9 in addition to the liquid crystal. Good.

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

Reference numeral 18 denotes a high-density optical disk attached to a spindle motor (not shown). The high-density optical disk 18 is often formed by laminating two disk substrates each having a thickness of about 0.6 mm. . The light beam 2b emitted from the light emitting point 2a of the light source 2 is
The light passes through the optical path dividing means 6 formed on the first inclined surface 5a and enters the optical path dividing means 15. After being substantially transmitted through the optical path splitting means 15, the light is converted into a light beam 2c by a collimator lens 16 and condensed by a condenser lens 17 as a light beam 2d. The condenser lens 17 is a high-density optical disk 18
The numerical aperture is designed to be about 0.6 so as to narrow down to a minute spot to such an extent that the data can be reproduced.

Next, referring to FIG.
Next, the optical path of the forward light for reproducing No. 9 will be described. Here, the thickness of the low-density optical disk 19 is about 1.2 mm. The outgoing 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 slope 11a of the second optical member 11, and enters the optical path dividing means 15. After being substantially reflected by the optical path splitting means 15, the light is converted into a light flux 9 c by the collimator lens 16.

FIG. 20 is a schematic diagram showing a change in the polarization direction of light in one embodiment of the present invention. As shown in FIG. 20, light that has passed through the optical path splitting unit 15 as linearly polarized light enters the aberration correcting unit 307. Here, the aberration corrector 307 is formed by dividing the electrode 321a. The wavefront of the passing light is controlled by the aberration correcting means 307, and the wavefront of the passing light can be corrected in advance so as to cancel the coma generated by the disc tilt. Then, the linearly polarized light whose wavefront has been adjusted by the aberration corrector 307 enters the 波長 wavelength plate 308. Here, when a voltage is applied to the 板 wavelength plate 308, the molecules of the liquid crystal 324 are tilted in the direction of the electric field due to the electric field generated thereby, and optical anisotropy occurs in the direction of the electric field when viewed from the incident side. By arranging and controlling the quarter-wave plate 308 such that the direction of the optical anisotropy is inclined at approximately 45 degrees with respect to the linearly polarized light, the linearly polarized light is converted into circularly polarized light. After that, the light converted into the circularly polarized light is condensed on the low-density optical disk 19 like a light beam 9d by the condenser lens 17.

At this time, the focal length L1 of the condenser lens 17 when reproducing the low-density optical disk 19 is set to be longer than the focal length L2 of the condenser lens 17 when reproducing the high-density optical disk 18. I have. The difference between the focal lengths is set to 1.0 mm or less, and preferably 0.6 mm or less. When each of a plurality of different types of discs is reproduced, it is almost necessary to largely drive the actuator holding the condenser lens 17. Disappears. Therefore, it is preferable because the focus position can be easily adjusted, and accordingly, the difference in the thickness of the substrate can be coped with very well.

As described above, 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 using the same optical pickup device. Become. That is, a low-density optical disk 19 such as a CD-ROM having a thickness of 1.2 mm and a high-density optical disk 18 such as a DVD formed by laminating a single plate having a thickness of 0.6 mm or both surfaces of the single plate are the same optical pickup. It is possible to record and reproduce on the device.

The focal 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 18 bonded thereto or an optical disk having a plurality of recording layers. .

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

First, the case where the high-density optical disk 18 is reproduced will be described. The light reflected by the high-density optical disk 18 and the information on the recording surface is added to the
8, the light is converted from circularly polarized light into linearly polarized light in a direction orthogonal to the original polarization direction.
5, and enters the optical path dividing means 6 formed on the first slope 5a 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 reflecting 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 low density optical disc 19 is reproduced will be described. The reflected light from the low-density optical disk 19 follows the same optical path as the outward path, and
The light 5 is reflected by the optical member 11 and enters the optical path dividing means 12 formed on the first slope 11 a of the optical member 11. Optical path splitting means 12
Here, since is formed of a polarization splitting film, the incident light is substantially reflected and guided to the reflection means 13. The reflecting means 13 is formed of an optical element according to the purpose. Here, an element for forming a focus error signal is provided. Accordingly, the light reflected by the reflecting means 13 is focused on the light receiving element 10 while forming a focus error signal, and detects a signal corresponding to data recorded on the low-density optical disc 19, a track error signal, and a focus error signal.

As described above, the optical path splitting means 6 and 12 are of a polarization separation type and are used in combination with the 波長 wavelength plate 308, so that the light use efficiency is improved and recording or recording on a plurality of types of optical discs is performed. This is preferable because reproduction can be performed. In addition, since the amount of light emitted from the light sources 2 and 9 can be suppressed, the life of the light sources 2 and 9 can be extended, and the reliability of the optical pickup device can be improved, which is preferable.

The quarter-wave plate 308 is connected to the aberration correcting means 3
07, the light incident on the aberration correcting means 307 can be converted into linearly polarized light, so that the correction of the disc tilt by the aberration correcting means 307 can be performed more reliably. In addition, a decrease in the amount of light in the aberration correction unit 307 can be suppressed to a minimum.

Next, when a plurality of light sources are arranged at different positions as described above, the wavefront aberrations generated in the light emitted from the respective light sources often differ greatly, and it is difficult to correct the wavefront aberrations. It is necessary to use a lens having a function of correcting aberrations that can be used as a condensing lens, and as a result, it is often necessary to use a plurality of condensing lenses corresponding to each light beam. In the present embodiment, the light emitting points 2a and 9a of the light sources 2 and 9 and the collimating lens
This problem is avoided by optimizing the distance between, so that this point will be described below.

FIG. 2 is a diagram showing the relationship between the light emitting point and the collimating lens in the infinite optical system according to the first embodiment of the present invention. In FIG. 2, L3 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 is a diagram showing the relationship between the amount of wavefront aberration and L3, L4 in the first embodiment of the present invention. That is, when the ratio of L3 and L4 is changed, the amount of wavefront aberration generated when the condenser lens is incident is shifted by 500 μm in the tracking direction of the condenser lens 17 (thick line) and when there is no shift in the tracking direction (Thin line). Generally, a condensing lens 17 for reproducing an optical disk
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 condenser lens 17 on the optical disk is 0.07λ in RMS value (where λ is Indicates the wavelength of light)
Taking into account that the light emission point 9a is less than the light emission point 9a, the amount of wavefront difference generated is relatively large, and the light incident condition on the condenser lens 17 becomes strict. Lens 17
If the wavefront aberration amount at the maximum shift amount of (500 μm) is 0.07λ or less, the light incident from both light emitting points on the condenser lens 17 is independent of the shift amount of the condenser lens 17. It is considered that the light is converged on the optical disk. As a range that satisfies this condition, as is apparent from FIG. 3, it is preferable that the ratio of L3 and L4 (L4 以下 L3 = H, hereinafter represented by H) is 0.50 <H <0.75. You can see that.

If the above 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 reflected light can be satisfactorily incident on the light receiving element. Thus, excellent signal characteristics can be obtained.

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

By arranging the optical systems 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 it is not necessary to provide a means for switching the condenser lens, thereby reducing the size of the optical pickup and the number of parts. Therefore, it is possible to improve the productivity, improve the reliability of the optical pickup by eliminating a complicated mechanism, improve the operation speed, and the like.

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

(Embodiment 2) Embodiment 2 of the present invention will be described below with reference to the drawings.

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

In FIG. 5, reference numeral 20 denotes a package, and the package 20 mounts the light source 2 for emitting light for the high-density optical disk 18, the light source 9 for emitting light for the low-density optical disk 19, the light source 2, and the light source 9. Substrate portion 2 on which a light source mounting portion 34 and a light receiving element 21 for receiving light reflected by the high-density optical disk 18 and the low-density optical disk 19 are mounted.
0a and a side wall 20b provided to cover these members. Package 20
The substrate portion 20a, the side wall portion 20b, the terminal 20c, and the opening portion 20d are substantially the same as the substrate portion 1a, the side wall portion 1b, the terminal 1c, and the opening portion 1d of the first package 1 except for the size. Have.

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.

[0119] Hereinafter, various optical elements existing in the optical member 22 will be described.

Reference numeral 23 denotes a diffusion angle conversion means. The diffusion angle conversion means 23 is provided on the end face of the second substrate 22e on the light source side so as to match the optical axis of the light emitted from the light source 2. That is, the light emitted from the light emitting point 2a of the light source 2 is viewed from the optical disk side, and the optical path is changed so that the light is emitted from a greater distance. It has the function of increasing the optical path length. The diffusion angle conversion means 23 is preferably formed of a diffraction grating, especially a hologram, because it can transmit light with high efficiency. In particular, it is preferable to use a hologram having a stepped cross-section or a saw-tooth cross-section of four or more steps because light can be used with high efficiency and a decrease in the amount of light can be prevented.

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

Since the filter 24 is formed on the first inclined surface 22a, the light emitted from the light source 2 can be transmitted with almost no hindrance, and the light guided from the light source 9 can be reflected. Light emitted from the light sources 2 and 9 can be guided to the recording medium at a high rate. Therefore, recording or reproduction on the recording medium can be performed without increasing the amount of light emitted from the light sources 2 and 9, and the light sources 2 and 9 are operated by operating the light sources 2 and 9 in a high output state. Can be shortened. Further, since the light source 2 and the light source 9 can be used in a low output state, the temperature of the light source 2 and the light source 9 hardly rises, so that the oscillation wavelength of the light source 2 and the light source 9 hardly shifts with the temperature change. . Accordingly, it is possible to provide a high-performance optical pickup capable of forming a focus more accurately.

Reference numeral 25 denotes a polarized light separating film. The polarized light separating film 25 has a function of transmitting light having a specific polarization direction and reflecting light having other polarization directions. Here, the polarization separation film 25 is formed by the P 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 S 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

Numeral 27 denotes a diffusion angle conversion means. The diffusion angle conversion means 27 is provided on the end face of the second substrate 22e on the light source side so as to match the optical axis of the light emitted from the light source 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.

Numeral 28 designates a plurality of beam forming means. The plurality of beam forming means 28 has a function of separating incident light into a plurality of light beams and reflecting the light beams.
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. In the convergence direction, and the light flux in the convergence direction is reflected 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 flux formed by the light emitted from the light source 2 as the zero-order light, and forms the light emitted from the light source 9. It is formed so that most of the light flux is diffracted into + 1st-order light. As a result, the light emitting point position of the light emitted from the light source 9 is moved to the forward (from the recording medium) light emitting point 9 e by the diffusion angle conversion means 27, so that the light flux from the light source 9 is received on the light receiving element 21. Diverged, RF
Since it is possible to prevent the signal detection, the focusing and the formation of the tracking signal from becoming difficult, it is possible to realize a high-performance optical pickup capable of reliably forming an accurate signal.

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.

Reference numeral 33 denotes 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 22d 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, 2 with respect to the optical axis of the light emitted from light source 9
7 are arranged substantially vertically.

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, multiple alignments can be omitted. Therefore, productivity can be greatly improved and manufacturing cost can be reduced.

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

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

As described above, by adopting a configuration in which light from a plurality of light sources having different oscillation wavelengths is made incident on the optical member 22 on which a plurality of optical elements are formed and guided to a predetermined optical path, Since a plurality of optical elements or the like provided for each light source can be integrated into one, the size of the entire optical pickup can be significantly reduced as compared with an optical pickup arranged in a dispersed manner, and each optical pickup can be reduced in size. There is no need to adjust the position of each optical element with respect to the light source, greatly improving productivity.Furthermore, mounting errors of each optical element can be minimized, so that good optical characteristics can be realized. As a result, 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.

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

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

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

With such a 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.

Therefore, there is almost no displacement between the light sources and no displacement 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 made equal. By arranging the light source 2 and the light source 9 in such a relationship, the light source 2 and the light source 9 can be fixed to, for example, the same parallel plane member, so that the height accuracy of the light source 2 and the light source 9 can be reduced. It can be easily secured. As a result, it is possible to suppress the deterioration of the optical characteristics caused by the lack of the height accuracy, so that an optical pickup having good recording or reproducing characteristics can be realized.

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 34. When assembling the optical head, the positioning between the optical member 22 and 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 a result, it is possible to easily connect the light source 2 and the light source 9 to the light source 2 and the light source 9 using wires used for connecting the light source 2 and the light source 9 to the electrodes and the ground for supplying power to the light sources 2 and 9. 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 sources 2 and 9 are 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. Since it is improved in one aspect, the number of manufacturing steps can be reduced, thereby improving the productivity and reducing the production cost.

Next, light emitted backward from the light sources 2 and 9 will be described.

FIG. 14 is an enlarged view near the light source according to the second embodiment of the present invention.

Since the semiconductor laser used as a light source in the present embodiment generally emits light from both end faces, a light emitting point for emitting forward light guided to a recording medium is provided at the light source 2 and the light source 9. In addition to the light emission point 2a and the light emission point 9a, there are also a light emission point 2g and a light emission point 9g that emit the rear emission light 2h and the rear emission light 9h.

The rear emission light 2h and the rear emission light 9h emitted from the light emitting points 2g and 9g are reflected by the substrate 20a if nothing is provided, and the light emitting points 2a and 9a May be incident on almost the same optical axis and become a stray light component. The presence of such stray light is not preferable because it causes deterioration of the optical characteristics of the optical pickup.

As a solution to this problem, in the present embodiment, the reflection member 35 is provided in the extending direction of the backward light 2h, 9h of the light source 2 and the light source 9, and therefore, this will be described.

The reflecting member 35 is mounted on the substrate portion 20a of the package 20, and the surface 35a opposite to the end surface 2i where the light emitting point 2g of the light source 2 is located is located on the end surface 2i.
A surface 35b is provided on the side of the light source 2 and is inclined on the side of the light source 9 with respect to the end surface 9i where the light emitting point 9g of the light source 9 is located.

Here, as a material for forming the reflecting member 35, a metal material having a high reflectance is used, or after forming the reflecting member 35 with an inexpensive material having a low reflectance, the surfaces 35a, 35a are formed.
It is preferable to form a film such as a metal or a dielectric having high reflectivity on the entire surface of b or a portion including a portion where light enters.

It is preferable that the inclination angles of the surfaces 35a and 35b of the reflecting member 35 are set in accordance with the diffusion angles of the light emitted from the light sources 2 and 9. That is, for example, the light source 2
When the diffusion angle of the light emitted from the light source 9 is larger than the diffusion angle of the light emitted from the light source 9,
By forming the inclination angle θ1 of 5a larger than the inclination angle θ2 of the surface 35b, not only the light from the light source 9 with a small diffusion angle, but also the light from the light source 2 that diffuses more is an optical member. Since the light can be prevented from being mixed into the predetermined optical path of 22 or into the light receiving element, generation of stray light can be greatly suppressed, and an optical pickup having good signal characteristics can be obtained.

In addition, by setting both the inclination angle of the surface 35a and the inclination angle of the surface 35b to θ2, the generation of the stray light is largely suppressed, and one setting of the inclined surface is performed in the manufacturing process of the reflecting member 35. Since both sides can be formed only by itself, the productivity can be improved and the cost can be reduced by simplifying the manufacturing process.

Further, the inclination angle is determined by the light sources 2 and 9 and the reflecting surface 35.
It is preferable to set in consideration of the distance to a and 35b.

In the present embodiment, the surfaces 35a and 35b of the reflecting member 35 are inclined in the xy directions in FIG. 14, but as shown in FIG. 15, the opposite sides of the light source mounting portion 34 in the yz directions. May be inclined. FIG. 15 is an enlarged view of the vicinity of the light source according to the second embodiment of the present invention. With such a configuration, the inclined surface formed on the reflecting member 35 is
5c, the reflection member 35 can be used.
Can be improved in productivity.

The surfaces 35a, 35b, 3 of the reflecting member 35
Although 5c was formed to have a high reflectance, the absorbance may be increased instead of increasing the reflectance. As a configuration for increasing the light absorption coefficient, the surface 35a of the reflection member 35,
It is conceivable to provide a light-absorbing film on the entire surface or a part of 35b and 35c. As the light absorbing film, a Si film, a Ti film, or a Si film + Ti film having a predetermined thickness is often used. It is also conceivable to attenuate the inside using a resin member or the like.

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

In the configuration using the light absorbing film, most of the energy of the absorbed light is converted into heat.
The material of the reflective member on which the light absorbing film is formed has good heat dissipation,
It is preferable to use a material having high thermal conductivity. By using such a material, it is possible to suppress the occurrence of inconvenience, such as a change in the composition of the light-absorbing film due to a high temperature of the reflection member 35 and a predetermined light-absorbing action being disabled.

In this case, the surfaces 35a, 35b and 35c of the reflecting member 35 which are inclined with respect to the end surfaces 2i and 9i of the light sources 2 and 9 in the case of reflecting light need not be inclined. The light absorption film may be formed directly on the substrate 20a.

With this configuration, the light sources 2 and
9 from the light emitting points 2g and 9g
a, 35b, and 35c, the light from the light emitting points 2g, 9g is absorbed by the optical member 22.
The optical pickup hardly becomes stray light upon entering the optical pickup, and an optical pickup having good signal characteristics can be realized.

Further, the light reflected by the surface 35a, 35b or 35c may be emitted to the outside of the package 20 from an opening different from the opening 20d provided in the side wall 20b of the package 20. Most preferred. With such a configuration, the backward emission light from the light sources 2 and 9 can be almost completely emitted to the outside of the package 20, so that the generation of stray light due to the backward emission light can be significantly reduced. it can. Note that in this case, it is preferable that the opening be covered with a light-transmitting member such as glass or resin because deterioration caused by the light source or the light-receiving element coming into contact with air or moisture can be suppressed.

The operation of the optical pickup having the above configuration will be described. Here, although not particularly shown, the aberration correcting means 307 and the quarter-wave plate 308 are arranged almost in the same manner as in the first embodiment.

When the recording medium is the high-density optical disk 18, recording or reproduction is performed using the light emitted from the light source 2. In this case, the diffusion angle of the light emitted from the light source 2 is reduced by the diffusion angle conversion means 23, that is, the spread of the light is reduced.

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

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

The light whose light spread has been reduced by the diffusion angle conversion means 23 almost passes through the filter 24 and almost also passes through the polarization separation film 25 provided thereafter. After passing through the lens 16 and being converted into parallel light, if there is no light, the light directly enters the aberration correction unit 307. Here, after the correction according to the disc tilt is made, the light enters the quarter-wave plate 308. Then, when passing through the quarter-wave plate 308, the light that has been linearly polarized light is converted into circularly polarized light, and the condensing lens 1
7 and is converged on the high-density optical disk 18.

The light reflected back from the high-density optical disk 18 is again incident on the quarter-wave plate 308, and when passing through it, is orthogonal to the polarization direction when the light source 2 is emitted from the circularly polarized light. Converted into linearly polarized light and corrected for aberration
7 and enters the polarization splitting film 25. Here, unlike the case, the polarization direction is different this time, so that the light is reflected by the polarization separation film 25 and enters the diffusion angle conversion means 31 via the reflection means 29 and 30. The light incident on the diffusion angle conversion means 31 is reflected without being diffracted,
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, and both an RF signal and a focus tracking signal are formed based on the light incident on the light receiving element 21. While performing reproduction, optimal control of the optical pickup is performed.

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

The light converted to 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 when there is a collimator lens, the collimator lens 16 Is converted into parallel light by passing through, and when there is no parallel light, the light directly enters the aberration correction unit 307 and the quarter-wave plate 308.

When passing through the quarter-wave plate 308, the light that has been linearly polarized light is converted into circularly polarized light, enters the condenser lens 17, and is converged on the low-density optical disk 19.

The light reflected by the low-density optical disk 19 and returned again enters the quarter-wave plate 308, and when passing through it, is orthogonal to the polarization direction when the light source 9 is emitted from the circularly polarized light. Converted into linearly polarized light and corrected for aberration
7 and enters the polarization splitting film 25. Here, unlike the case, the polarization direction is different this time, so that the light is reflected by the polarization separation film 25 and enters the diffusion angle conversion means 31 via the reflection means 29 and 30. The light incident by the divergence angle conversion means 31 is almost diffracted into + primary light and reflected, and the light that was diffused before being incident is converted into convergent light. The light enters the signal forming means 32.

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

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

FIG. 6 is a diagram showing a relationship between a light emitting point and a collimating lens in an infinite optical system according to Embodiment 2 of the present invention. 6, L5 indicates the distance from the collimator lens 16 to the virtual light emitting point 2e, and L6 indicates the distance from the collimator lens 16 to the virtual light emitting point 9e. FIG. 7 shows the relationship between the amount of wavefront aberration and L5 and L6 depending on whether or not the objective lens is shifted according to the second embodiment of the present invention. That is, when the ratio of L5 to L6 is changed, the amount of wavefront aberration generated when the condenser lens is incident is shifted by 500 μm in the tracking direction of the condenser lens 17 (thick line) and when there is no shift in the tracking direction (Thin line). Generally, the focusing lens during reproduction of the optical disc may shift up to about 500 μm in the tracking direction, and the amount of wavefront aberration allowed for effectively converging the light incident on the focusing lens on the optical disc is an RMS value. 0.07λ
(However, λ indicates the wavelength of light) Considering that it is less than or equal to the above, light from the light emitting point 9a where the amount of occurrence of aberration is relatively large and the condition of light incidence on the condenser lens 17 becomes strict is considered. On the other hand, the shift amount of the condenser lens 17 is maximum (500 μ
If the wavefront aberration amount at the time of m) is 0.07λ or less, the light from both light emitting points incident on the condenser lens 17 is converged on the optical disk regardless of the shift amount of the condenser lens 17. It is thought that it will be. As a range that satisfies this condition, as is clear from FIG. 7, the ratio of L5 to L6 (L6 ÷ L5 = H, hereinafter represented by H) is 0.50 <
It is understood that it is preferable that H <0.75.

If this range is satisfied, the amount of wavefront aberration generated in the light reflected and returned by the recording medium can be suppressed, so that the light receiving element 21 for receiving the reflected light can be suppressed.
And 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 satisfying this condition, as is clear from FIG. 7, the ratio (H) between L5 and L6
0.55 <H <0.70 is preferable because the signal characteristics can be further improved.

By arranging the optical system so that the value of H is 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 it is not necessary to provide a switching means for the condenser lens, thereby reducing the size of the optical pickup and the number of parts. Therefore, it is possible to improve the productivity, improve the reliability of the optical pickup by eliminating a complicated mechanism, 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, since the space for disposing the collimator lens 16 is not required as compared with the infinite system, the size of the entire optical pickup can be reduced.

Various combinations of the light source 2 and the light source 9 are conceivable. For example, 650 nm and 780 nm, 490 nm and 650 nm, and 400 n
m and 650 nm may be sufficient, that is, the wavelength of one light source is long and the wavelength of one light source is shorter. The number of light sources provided may be two or more.

(Embodiment 3) Hereinafter, Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 8 is a cross-sectional view of an integrated optical head according to Embodiment 3 of the present invention, and FIG. 9 is a cross-sectional view illustrating an optical path according to Embodiment 3 of the present invention. Here, the front sectional view in FIG. 9 depicts the optical path in a straight line. 8 and 9,
Members having the same configurations as those of the first and second embodiments are denoted by the same reference numerals.

In FIGS. 8 and 9, reference numeral 40 denotes a package. The package 40 includes a light source 2 for emitting light for the high-density optical disk 18, a light source 9 for emitting light for the low-density optical disk 19, and the high-density optical disk 18. The light receiving means 58 and 59 for receiving the light reflected by the low-density optical disk 19 are formed by a substrate portion 40a on which the light receiving means 58 and 59 are placed and a side wall portion 40b provided so as to include those members. Substrate 40a, side wall 4 constituting package 40
0b, terminals 40c and openings 40d have substantially the same configuration as the substrate 1a, side walls 1b, terminals 1c and openings 1d of the first package 1 except for the size.

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

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

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

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

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

Next, the backward emission light from the light sources 2 and 9 will be described.

FIG. 16 is an enlarged view near the light source according to the third embodiment of the present invention.

In the present embodiment, the reflecting members 60 and 61 extend in the extending direction of the backward light 2h, 9h of the light source 2 and the light source 9.
This will be described.

The reflecting members 60 and 61 are
Light source 2 of the light source 2
g of the reflecting member 60 facing the end face 2i where the g exists.
a is provided to be inclined toward the light source 2 with respect to the end face 2i, and the surface 61a of the reflecting member 61 facing the end face 9i where the light emitting point 9g of the light source 9 exists is located with respect to the end face 9i.
It is provided to be inclined toward the light source 9.

Here, as a material for forming the reflecting members 60 and 61, a metal material having a high reflectivity is used, or the surfaces 60a and 61a are formed after forming the reflecting members 60 and 61 with an inexpensive material having a low reflectivity. It is preferable to form a film such as a metal or a dielectric having a high reflectivity on the entire surface or a part thereof.

Here, the reason why the reflecting member 60 and the reflecting member 61 are separately provided will be described.

The light source 2 and the light source 9 used in the present embodiment have different oscillation wavelengths in order to correspond to different recording media. In the present embodiment, a light source between 630 and 660 nm is used as the light source 2, and a light source between 770 and 800 nm is used as the light source 9.

Generally, in a metal or dielectric material used to reflect light, the ratio of the reflected light to the incident light (reflectance) changes according to the wavelength of the incident light. That is, the wavelength dependence of the reflectance often exists. Therefore, when both the light from the light source 2 and the light from the light source 9 are reflected by the reflecting member having the same configuration, the ratio of the light from the light source 2 and the light from the light source 9 is different, resulting in an increase in scattering and the like. The inconvenience may occur.

Therefore, in the present embodiment, the reflecting member 60 and the reflecting member 61 are provided separately, and the materials constituting each are made different. That is, the reflecting member 60 is made of a material having a large reflectance with respect to the wavelength of the light emitted from the light source 2.
And the reflecting member 61 is made of a material having a large reflectance with respect to the wavelength of light emitted from the light source 9.

By adopting such a configuration, both the backward emission light emitted from the light source 2 and the light source 9 can be reflected well in a predetermined direction, and the light is scattered by the surface 60a and the surface 61a. This is preferable because stray light can be prevented from being incident on members, light receiving means, and the like.

The same effect can be obtained even if the reflecting members 60 and 61 are formed of the same material and the respective surfaces 60a and 60b are formed with reflecting films having different structures such as materials or film thicknesses. it can.

It is preferable that the inclination angle between the surface 60a of the reflecting member 60 and the surface 61a of the reflecting member 61 is set according to the diffusion angle of the light emitted from the light source 2 and the light source 9. That is, for example, the diffusion angle of the light emitted from the light source 2 is
When the diffusion angle of the light emitted from the light source 9 is smaller than the magnitude, the inclination angle θ1 of the surface 60a is changed to the inclination angle θ of the surface 61a.
By making it smaller than 2, the light from the light source 9 with a small diffusion angle, as well as the light from the light source 2 that diffuses more, does not enter into the predetermined optical path of the optical member 40 or the like. Therefore, generation of stray light can be greatly suppressed, and an optical pickup having good signal characteristics can be obtained.

By setting both the inclination angle of the surface 60a and the inclination angle of the surface 61a to θ2, the production process of the reflection member 60 and the reflection member 61 can be made substantially the same while greatly suppressing the generation of stray light. Therefore, it is possible to improve productivity and reduce costs by simplifying the manufacturing process.

Further, the inclination angle is determined by the light source 2, 9 and the reflecting surface 61.
It is preferable to set in consideration of the distances to a and 61b.

The surfaces 60a, 61 of the reflecting members 60, 61
Although a has been formed to have a high reflectance, absorptivity may be increased instead of increasing the reflectance. As a configuration for increasing the light absorption coefficient, it is conceivable to provide a light absorbing film on the entire surface or a part of the surfaces 60a and 61a. As the light absorbing film, a Si film, a Ti film, or a Si film + Ti film having a predetermined thickness is often used. It is also conceivable that the internal pressure is attenuated by using a resin member or the like.

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

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

With such a configuration, the light sources 2 and
9, light from the light emitting points 2g and 9g is absorbed by the surfaces 60a and 61a without being substantially reflected.
Light from g and 9g hardly enters the optical member and becomes stray light, so that an optical pickup having good signal characteristics can be realized.

In the case of reflecting light, the surfaces 60a and 61a of the reflecting members 60 and 61 which are inclined with respect to the end faces 2i and 9i of the light sources 2 and 9 need not be inclined in this case.

In the present embodiment, the reflecting members 60 and 61 are provided on the substrate 40a of the package 40, but they may be provided on the light source mounting section 42,
It may be provided on the light receiving means 58, 59.

Further, the light reflected by the surfaces 60a and 61a is transmitted to the opening 40d provided in the side wall 40b of the package 40.
Most preferably, the light is emitted to the outside of the package 40 from another opening. With such a configuration, the backward emission light from the light sources 2 and 9 can be almost completely emitted to the outside of the package 40, so that the occurrence of stray light due to the backward emission light can be significantly reduced. it can.

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

Hereinafter, various optical elements present in the first optical member 41 will be described.

First, a reflection film 43 and a reflection film 44 are formed on the first slope 41a. The reflection film 43 is provided for the light source 2
Has a function of reflecting the light emitted from the light source 9 in a predetermined direction, and the reflection film 44 has a function of reflecting the light emitted from the light source 9 in a predetermined direction. The materials constituting the reflection films 43 and 44 are Ag, A
It is preferably formed by using a metal material having high reflection such as u or Cu or a plurality of dielectric materials having different refractive indices, and alternately providing a plurality of layers of each material.

In the present embodiment, the reflection film 43 and the reflection film 44 are provided separately, but 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 a mask or the like can be omitted and the mask for forming the reflective film can be omitted, so that productivity can be improved and manufacturing cost can be reduced. Can be.

On the second inclined surface 41b, polarization separation films 45 and 46 are formed. 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.
This is preferable because the polarization component and the S polarization component can be separated. In particular, here, it is formed so as to transmit the S-polarized light component emitted from the light source 2 and the light source 9 and reflect the P-polarized light component.

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

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

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, 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 a photocurable resin, an epoxy resin, or the like. The second optical member is formed of a substantially parallel flat plate having opposing surfaces, and the light from the light source 9 is transmitted at one end surface thereof. ing.

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 match the optical axis of the light emitted from the light source 9. The function of making the diffusion angle negative, that is, the light emitting point 9 of the light source 9
When the light emitted from a is viewed from the optical disk side, it has a function of changing the optical path so that the light is emitted from a closer position. The light emitting point is shifted in a direction substantially approaching the recording medium. Thereby, the light emitting point of the light source 9 becomes the true light emitting point 9a.
From the light source 9 to the apparent light emitting point 9e, and thus has the 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, particularly a hologram, because it can transmit light with high efficiency. In particular, it is preferable to use a hologram having a stepped cross-section or a saw-tooth cross-section of four or more steps because light can be used with high efficiency and a decrease in the amount of light can be prevented.

Next, the third optical member 49 will be described.

The third optical member 49 is provided on the upper surface of the second optical member 47, and the second optical member 47 and the third optical member 49 are joined by a bonding material such as an ultraviolet curing resin, an epoxy resin, or a bonding glass. Are joined.

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

In the present embodiment, the beam separating section 50b also has a function as a stop for the light from the light source 9. In the present embodiment, one condenser lens 1
Although both light from the light sources 2 and 9 are made incident on 7, the entrance pupil of the condenser lens 17 is adjusted so that the light from the light source 2 is focused on the recording surface of the high-density optical disk 18.
Accordingly, in this case, the shape and material of the condenser lens 17 are adjusted so that light from the light source 2 is focused on the recording surface of the high-density optical disk 18.

In order to focus the light from the light source 9 on the recording surface of the low-density optical disk 19 by such a condensing lens 17 in this embodiment, the light from the light source 9 incident on the condensing lens 17 is used. Is adjusted to be smaller than the diameter of the light from the light source 2. In general, the lens has a stronger light collecting action at the periphery than at the center.
For this reason, if the light is largely spread and incident, the focal point is formed closer, and if the light is incident without widening the light, the focal point is formed farther. In the present embodiment, the recording surface of the low-density optical disk 19 is provided farther from the recording surface of the high-density optical disk 18, so that the entrance diameter of the light from the light source 9 to the condenser lens 17 is optimized. The light from the light source 9 can be condensed on the recording surface of the low-density optical disk 19 by the condensing lens 17 designed according to the light from the light source 2.

The diameter of the entrance aperture is adjusted by the beam separation section 50b. That is, the size of the beam separation unit 50b is adjusted so that the light reflected by the beam separation unit 50b has a predetermined diameter on the condenser lens 17.

The function of such an aperture is provided by the beam separation unit 50b.
, The diameter of the light emitted from the light source 9 can be accurately adjusted, so that the diameter of the light incident on the condenser lens 17 can be made a predetermined size. 9 can be focused on the recording surface on the low-density optical disk 19 by the focusing lens 17. In addition, the number of components can be reduced as compared with the case where the aperture is provided separately, and the labor for adjusting the position between the aperture and the light source 9 can be reduced, so that the productivity of the optical pickup can be improved.

By providing a stop at this position,
Of the light emitted from the light source 9, the light not reflected by the beam separation unit 50 b passes through the first slope 49 a as it is and is emitted to the outside of the optical member 49. It is possible to prevent the light from becoming stray light inside.

Further, light traveling toward the low-density optical disk 19 passes through the polarization separation film 50a and enters the beam separation portion 50b, but return light reflected by the low-density optical disk 19 is reflected by the polarization separation film 50a. Therefore, it is configured to hardly enter the beam separation unit 50b. By providing the beam separating portion 50b of the multiple beam forming means 50 having such a configuration with a stop function, for example, the condenser lens 17 is shifted, and the optical axis of the returning light is shifted from a predetermined position. Even in the case where the light is hardly incident on the beam separating portion 50b having the function of the stop, the light which should be incident on the light receiving means is blocked by the stop, and the amount of light incident on the light receiving means is reduced, or the distribution of the light amount is reduced. Unbalance can be prevented from occurring. Therefore, it is preferable because a more accurate RF signal can be obtained and a servo signal for focusing / tracking can be formed more accurately.

Further, the stop can be provided at a position which is both the optical path of the outgoing light and the optical path of the returning light, so that the space utilization efficiency in the optical pickup can be improved. In other words, it is not necessary to provide a separate optical path for return light so that return light does not pass through the stop, which is preferable because further miniaturization of the optical pickup can be realized.

Further, the beam separating section 50b is provided on the optical path through which the light from the light source 9 passes, and the light from the light source 9 enters, but the light from the light source 2 to the high-density optical disk 18 does not enter. The stop for the light from the light source 9 does not block or adversely affect the light from the light source 2. Therefore, in particular, in an optical pickup having a configuration in which a plurality of light sources are housed in one package and light from the plurality of light sources is condensed at a predetermined position by one condensing lens, the light from the plurality of light sources is This is a preferable configuration because the light can be incident on the condenser lens with a predetermined diameter without adversely affecting the light.

The plurality of luminous fluxes formed here are applied to a predetermined position on the track of the low-density optical disc 19, and the light quantity of the returned light is compared to perform tracking of the low-density optical disc 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 diaphragm film having a mere diaphragm function is provided instead of providing the beam separation section 50b, so that the diaphragm film has a function as a diaphragm means instead of a plural beam forming means. To do.

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

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

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

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 entering the filter 51 is a plane including the light traveling through the first optical member 41. It is formed so as to proceed in a substantially vertical direction.

Next, the fourth optical member 53 will be described.

The fourth optical member 53 is joined to the bottom surface of the first optical member 41 by a photo-curable resin or an epoxy resin, and has a function of guiding return light reflected by the recording medium to a predetermined position. Have. The fourth optical member 53 has a first slope 53a and a second slope 53b, and an optical element according to the purpose is formed on each slope.

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

[0247] 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 light transmitted through the optical path dividing means 54 and 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.

Next, the aberration correcting means 307 will be described. The basic configuration of the aberration correcting unit 307 is almost the same as that shown in the first embodiment, but the arrangement position is different. In the present embodiment, the aberration correcting means 307 is provided so as to close the opening 40d provided in the side wall 40b of the package 40. And the aberration correcting means 307
Wiring for supplying power to the power supply 323 of the side wall portion 4
0b via an insulating layer.
Are electrically connected by bonding or the like to a part of the terminal 40c provided in the terminal.

By providing the aberration correcting means 307 in the package 40 in this manner, the aberration correcting means 307 can be provided closer to the light sources 2 and 9, so that the size of the aberration correcting means 307 can be reduced. And by fixing it to the package 40 in advance,
The alignment process at the time of assembling the optical pickup can be simplified, and the occurrence of positional deviation can be suppressed. Therefore, an optical pickup with high productivity and low cost can be provided.

The 波長 wavelength plate 308 is used in Embodiment 1.
Although it is provided at almost the same position as that shown in the figure, it may be provided on the upper surface of the aberration correcting means 307 (on the side of the condensing means) via a bonding material. In this case, the aberration correction means 307 and the １ ／ wavelength plate 308 may be joined to the package 40 in an integrated state, or the aberration correction means 307 and the 1/4 wavelength plate 308 may be joined to the package 40. 4 wavelength plate 3
08 may be joined in order.

In any case, the alignment process at the time of assembling the optical pickup can be further simplified, and the occurrence of positional deviation can be suppressed more effectively. In addition, since the aberration correcting means 307 and the quarter-wave plate 308 can be provided close to each other, it is easy to arrange wiring used for power supply to both of them, and the wiring is configured by the same FPC (flexible printed circuit). Therefore, the number of parts can be reduced.

Further, it is preferable that the light sources 2 and 9, the light receiving means 58 and 59, and the optical members 41, 47, 49 and 53 are present in a closed space as in the first embodiment.

As described above, by adopting a configuration in which light from a plurality of light sources having different oscillation wavelengths is made incident on an optical member on which a plurality of optical elements are formed, and guided to a predetermined optical path, the conventional structure 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, it is not necessary to adjust the position of each optical element with respect to each light source, so that the productivity is greatly improved. Further, the mounting error of each optical element can be suppressed to the minimum, so that good optical characteristics can be obtained. Characteristics can be realized.

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

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 one optical member. The optical pickup can be made smaller 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.
The thickness can be reduced.

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

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

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

With such a 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.

Since the light from the plurality of light sources 2 and 9 is made incident on the same surface of the optical member as in the present embodiment, the number of surfaces that must be subjected to such precision processing can be reduced. Therefore, the manufacturing process associated with precision machining 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 displacement between the light sources 2 and 9 and between the light sources 2 and 9 and the optical element, and a highly reliable optical pickup having good optical characteristics can be realized.

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

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 more 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 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 high-density optical disk 18, recording or reproduction is performed using the light emitted from the light source 2. In this case, the light emitted from the light source 2 is first reflected by the reflection film 43 formed on the first slope 41a of the first optical member 41, and 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.

After that, 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 inclined surface 49 b of the third optical member 49, exits from the third optical member 49, and enters the aberration correction unit 307.

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.
The light enters the four-wavelength plate 308. The quarter-wave plate 308 converts the linearly polarized light up to that into circularly polarized light, then enters the condenser lens 17 and converges on the high-density optical disk 18.

The light reflected by the high-density optical disk 18 and returned returns to the quarter-wave plate 308 again. When this light is reflected by the high-density optical disk 18, the rotation direction of the elliptically polarized light is opposite to that at the time of incidence. Is converted into linearly polarized light substantially orthogonal to the polarization direction at the time of emission. That is, the light emitted as S-polarized light when emitted from the light source 2 enters the optical member as P-polarized light.

The light having passed through the quarter-wave plate 308 passes through the aberration correcting means 307 and enters the third optical member 49.
The light almost passes through the filter 51 formed on the second inclined surface 49 b, is emitted from the third optical member, passes through the second optical member 47, and enters the first optical member 41.

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

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

The light transmitted through the optical path splitting means 54 is
A light beam having a predetermined shape is formed on a light receiving portion formed at a predetermined position of the light receiving means 58 provided on the lower surface of the fourth optical member 53 as it is, and is used for signal formation according to the purpose.

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

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

[0279] Thereafter, the light emitted from the first optical member 41 enters the diffusion angle conversion means 48 formed on the end face of the second optical member 47. The light emitted from the light source 9 is converted into a diffusion angle by the diffusion angle conversion means 48, and the light that has been the diffused light becomes convergent light, is emitted from the second optical member 47, and enters the third optical member 49. I do.

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

After that, the light emitted from the light source 9 is incident on the aberration correcting means 307, and after being corrected for the disc tilt, if there is a collimator lens 16, it passes through the collimator lens 16 and is converted into substantially parallel light. Since being done
If not, the light is directly incident on the 板 wavelength plate 308. The light incident on the 波長 wavelength plate 308 is converted from linearly polarized light into elliptically polarized light and emitted from the 波長 wavelength plate 308. Thereafter, the light emitted from the light source 9 enters the condenser lens 17 and converges on the low-density optical disc 19.

The light reflected by the low-density optical disk 19 and returned returns to the quarter-wave plate 308 again. When this light is reflected by the low-density optical disk 19, the direction of rotation 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 308 passes through the aberration correcting means 307 and enters the third optical member 49.
The light is almost reflected by the filter 51 formed on the second slope 49b, and is incident on the multiple beam forming means provided on the first slope 49a. 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 diffusion angle, becomes convergent light, passes through the second optical member 47, and enters the first optical member 41.

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

The light incident on the fourth optical member 53 is incident on the optical path dividing means 55 formed on the first slope 53a of the fourth optical member 53. About half of the incident light is transmitted and almost half is reflected by the light path dividing means 55.

The light transmitted through the optical path dividing means 55 is
A light beam of a predetermined shape is formed on a light receiving portion formed at a predetermined position of the light receiving means 59 provided on the lower surface of the fourth optical member 53 as it is, and is used for signal formation according to the purpose.

The light reflected by the optical path 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 2 and 9 are arranged in the same package, the wavefront aberration generated in the light emitted from each light source often differs greatly as in the second embodiment. Therefore, the distances between the light emitting points 2a and 9a of the light sources 2 and 9 and the collimating lens are optimized. However, since the concept is the same as in the second embodiment, the description is omitted here.

As described above, in the present embodiment, the light source 2 is provided on the side surface 42a of such a light source mounting portion 42.
And the light source 9 are disposed at substantially the same height from the bottom surface of the light source mounting portion 42. That is, a straight line connecting the light emitting point 2a of the light source 2 and the light emitting point 9a of the light source 9 is substantially perpendicular to the surface of the recording medium.

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

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

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

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

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

(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 sectional view showing an optical path according to the fourth embodiment of the present invention. Here, the 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 is a slight difference in the size, shape, etc. of any of its components, the substrate portion 70a, the side wall portion 70b, the terminal 70c, the opening 70d, the substrate portion 40a, the side wall portion 40b of the package 40 , The terminal 40c and the opening 40d, and the description is omitted.

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

Next, the light emitted backward from the light sources 2 and 9 will be described.

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

As shown in FIG. 17, in the present embodiment,
Since the reflecting member is provided in the extending direction of the rear emission lights 2h and 9h of the light source 2 and the light source 9, this will be described.

The reflecting member 93 is mounted on the substrate portion 70a of the package 70, and the surface 93a facing the end face where the light emitting point 2g of the light source 2 exists is inclined toward the light source 2 with respect to the end face. In addition, a surface 93b facing the end face where the light emitting point 9g of the light source 9 exists is provided to be inclined toward the light source 9 with respect to the end face.

Here, as a material for forming the reflecting member 93, a metal material having a high reflectivity is used, or after forming the reflecting member 93 with an inexpensive material having a low reflectivity, the surfaces 93a and 93a are formed.
It is preferable to form a film such as a metal or a dielectric having high reflectivity on the entire surface of b or a portion including a portion where light enters.

Although the surfaces 93a and 93b of the reflection member 93 are formed to have a high reflectance, the light absorption may be increased instead of increasing the reflectance. As a configuration for increasing the light absorption coefficient, it is conceivable to form the reflection member 93 with translucent glass or resin, or to provide a light absorption film on the entire surface or a part of the surfaces 93a and 93b of the reflection member 93. As the light absorbing film, a Si film, a Ti film, or a Si film +
In many cases, a Ti film is used at a predetermined thickness. It is also conceivable to attenuate inside a translucent resin member or the like.

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

In the structure in which the light absorption coefficient is increased, much of the energy of the absorbed light is converted into heat. Therefore, the material of the reflecting member 93 on which the light absorbing film is formed has a good heat dissipation property and a high heat conduction property. It is preferable to use a material having a high rate.
By using such a material, it is possible to suppress the occurrence of inconvenience, such as a change in the composition of the light-absorbing film due to a high temperature of the reflection member 93 and a failure to perform a predetermined light-absorbing action.

In this case, the surfaces 93a and 93b of the reflecting member 93 which are inclined with respect to the end surfaces of the light sources 2 and 9 in the case of reflecting light need not be inclined.

Also, without providing the reflecting member 93, the substrate 70a
May be directly provided with a light absorbing film.

[0310] With such a configuration, the light sources 2 and
9 from the light emitting points 2 g and 9 g
a and 93b, which are absorbed almost without being reflected, so that the light from the light emitting points 2g and 9g hardly enters the optical member 22 and becomes stray light, thereby realizing an optical pickup having good signal characteristics. Can be.

Further, the light reflected by the surfaces 93a and 94a is transmitted to the opening 70d provided in the side wall 70b of the package 70.
Most preferably, the light is emitted to the outside of the package 70 from another opening. With such a configuration, the backward emission light from the light sources 2 and 9 can be almost completely emitted to the outside of the package 70, so that the generation of stray light due to the backward emission light can be significantly reduced. it can.

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

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

Further, the first slope 72a and the second slope 72
Various optical elements are formed on b and the third inclined surface 72c.

Hereinafter, various optical elements existing in the first optical member 72 will be described.

First, a reflection film 73 and a reflection film 74 are formed on the first inclined surface 72a. The reflection film 73 is a light source 2
Has a function of reflecting the light emitted from the light source 9 in a predetermined direction, and the reflection film 74 has a function of reflecting the light emitted from the light source 9 in a predetermined direction. The materials constituting the reflection films 73 and 74 include Ag, A
It is preferably formed by alternately providing a plurality of layers of a highly reflective metal material such as u or Cu or a plurality of dielectric materials having different refractive indexes.

The reflecting film 73 and the reflecting film 74 may be provided separately, or may be formed as a single large reflecting film on almost the entirety of the first inclined surface 72a. When formed entirely, the process of forming a reflective film using a mask can be omitted and the number of masks for forming the reflective film can be reduced, so that productivity can be improved and manufacturing costs can be reduced. Can be reduced.

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

It is possible to more accurately separate the P-polarized light component and the S-polarized light component by forming such a polarization separating film 75, 76 by alternately providing a plurality of dielectric materials having different refractive indexes. It is preferred. In particular, here, the P-polarized component emitted from the light source 2 and the light source 9 is transmitted, and S
It is formed so as to reflect a polarization 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 a predetermined surface light amount can be obtained with a small output, and a long life of each light source can be realized.

The polarization separation films 75 and 76 may be provided separately, or may be formed as a single large film over substantially the entire upper portion of the second inclined surface 72b. When formed entirely, the process of forming a polarization separation film using a mask or the like can be omitted and the number of masks for forming the polarization separation film can be reduced, so that productivity can be improved and manufacturing can be performed. Cost can also be reduced. When provided separately, the optimum film can be provided according to the wavelength to be transmitted.
More reliable polarization separation can be performed.

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

Next, another optical member provided on the second inclined surface 72b will be described.

Reference numerals 77 and 78 denote holograms for monitor light. The hologram 77 is emitted from the light source 2,
Has the function of reflecting and diffracting a part of the light reflected by the light source 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 91. 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 at 8 is guided to a reflection section 80 provided on the upper surface of the first optical member 72, and thereafter, the light receiving means 92
The light enters the monitor light receiving unit provided above. Then, the power applied to the light source 9 is adjusted based on the electric signal from the monitor light receiving unit, and control is performed so that the amount of light emitted from the light source 9 always becomes an optimum value.

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

The reflecting films 81 and 82 have substantially the same configuration as the reflecting films 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 91, 92, etc. are arranged be hermetically closed. With such a configuration, it is possible to prevent impurities such as dust and moisture from entering the inside of the package, so that the performance of the light sources 2 and 9 and the light receiving units 91 and 92 can be maintained and emitted. Also, the deterioration of the optical characteristics of the light can be prevented.

For this reason, a shield member 85 is provided. The shield member 85 is provided on the side wall 70 of the package 70.
It is provided so as to close the opening 70d provided in the package 70b, and has a function of sealing the inside of the package 70. The sealed space is filled with an inert gas such as N ₂ gas, dry air, or Ar gas.
It is more preferable because condensation can be prevented from occurring on the surface of the light source and the like, thereby deteriorating the optical characteristics and the deterioration of the characteristics due to oxidation of the light sources 2 and 9 and the light receiving means 91 and 92.

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

Next, the second optical member 86 will be described.

The second optical member 86 is provided so as to cover the opening 70d provided in the side wall 70b of the package 70. The side wall 70b of the package 70 is made of a photo-curing resin, an epoxy resin, and an adhesive glass. And so on. The second optical member 86 has a first substrate 86a and a second substrate 86b. 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 through which light from the light source 9 passes on the end face on the shield member 85 side. Is formed with a diffusion angle conversion means 87. The divergence angle conversion means 87 has substantially the same configuration as the divergence angle conversion means 48 shown in the third embodiment, and a description thereof will be omitted.

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

The structure of the second substrate 86b is basically the same as that of the third optical member 49 shown in the third embodiment. The first substrate 86b has a first slope 86d, a second slope 86e, and a second slope 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 portion 70b are performed using a bonding material such as a photo-curing resin, an epoxy resin, or a bonding glass.

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

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

Numeral 90 denotes a composite optical member formed by integrating a quarter-wave plate and aberration correcting means, and has a structure shown in FIG. Here, FIG. 21 is a cross-sectional view of the composite optical member according to one embodiment of the present invention.

In FIG. 21, 329, 330, 331
Are substrates, and the substrates 329, 330, and 331 are all made of a material having a certain degree of hardness, such as glass, and having a transmittance of about 90% or more with respect to the wavelength of incident light. It is preferable because the decrease can be suppressed. As such a material, it is preferable to use BK-7, SF-11, or the like in terms of cost, productivity, and the like.

A liquid crystal functioning as an aberration correcting means 332 is filled between the substrate 329 and the substrate 330, and a 波長 wavelength plate 33 is provided between the substrate 331 and the substrate 330.
The liquid crystal which functions as 3 is filled.

An electrode 330 for applying a voltage to the aberration correcting means 332 and the quarter-wave plate 333 is provided on the surface of each of the substrates 329, 330, 331 facing the liquid crystal.
a, 330b, 329a and 331a are formed.
In particular, it is preferable that each of the electrodes 330a and 331a is divided into a plurality of portions so that the wavefront can be corrected in a wider range.

Reference numerals 334 and 335 denote power supplies.
Is to apply a predetermined voltage to 331a and 330a, and by controlling this voltage, the wavefront of the passing light can be controlled. Therefore, by correcting the wavefront of the light passing therethrough in advance so as to cancel the coma caused by the tilt, the amount of the aberration such as the coma caused by the tilt can be suppressed to the minimum. . When the electrodes are provided separately, the voltage applied to each electrode can be made different to control the wavefront of the passing light more finely, and the coma generated by the disc tilt can be reduced. It can be removed more efficiently.

Further, the aberration correcting means 332 includes the light sources 2 and 9
It is preferable to control the wavefront for the light emitted from any of the above. Therefore, it is necessary to change the control of the voltage applied between the liquid crystal electrodes depending on which of the light sources 2 and 9 the light is emitted. Therefore, control means (not shown) for controlling the power supply 334 for applying a voltage to the electrodes 331a and 330a of the aberration correction means 332
Power supply 33 based on the information of which one is emitting light.
4 is preferably controlled. Thereby, the light sources 2, 9
Optimum wavefront control can be performed for light from any of the above. Information on which of the light sources 2 and 9 is emitting light can be obtained by, for example, a control unit (not shown) of the light sources 2 and 9.
May be based on a signal from a disc determination unit (not shown) for detecting which type of optical disc is set, or may use other known methods. Good.

The power supply 335 applies a predetermined voltage to the electrodes 330b and 329a. By controlling this voltage, the amount of twist of the liquid crystal constituting the quarter-wave plate 333 is changed. Here, the electrodes 330b and 329a are preferably formed according to the diffusion angle of the incident light. That is, the diffusion angle is large, and the light passing therethrough is the liquid crystal 324.
When the distance through which light is transmitted is large, it is preferable to optimize the voltage to be applied by dividing the electrodes so that the twist amount decreases as the distance to the periphery increases.

By controlling the incoming voltage, the phase of light passing in a specific direction can be shifted by ４ wavelength, and the incoming linearly polarized light can be converted into circular or elliptically polarized light. .

Further, the さ ら に wavelength plate 333 includes the light sources 2 and 9
It is preferable to shift the phase of light in a specific direction by 1/4 wavelength for light emitted from any of the above. Therefore, it is necessary to change the control of the voltage applied between the electrodes 329a and 330b depending on which of the light sources 2 and 9 the light is emitted. Therefore, the electrode 32 of the 波長 wavelength plate 333
It is preferable that a control unit (not shown) that controls the power supply 335 that applies a voltage to 9a and 330b controls the power supply 335 based on information on which of the light sources 2 and 9 is emitting light. Thereby, optimal wavefront control can be performed for light from any of the light sources 2 and 9. The information on which of the light sources 2 and 9 is emitting light may be based on, for example, a signal from a control unit (not shown) of the light sources 2 and 9 or may indicate which type of optical disc is set. The detection may be based on a signal from a disk determination unit (not shown) for detection, or another known method may be used.

Thus, by optimally controlling the voltage applied to the liquid crystal according to the wavelength of the incident light, the light emitted from both of the light sources 2 and 9 can be accurately controlled. Since the phase can be shifted by ４ wavelength, any incident light can be reliably converted from the incident linearly polarized light into circularly polarized light, and the light reflected from the optical disks 310 and 311 can be converted to the original light. Can be reliably converted to linearly polarized light orthogonal to the linearly polarized light.
Since the use efficiency of any light emitted from the light sources 2 and 9 can be improved, the output of each of the light sources 2 and 9 can be used in a low state, so that power consumption can be reduced. At the same time, the life of the light sources 2 and 9 can be prolonged, and the reliability of the optical pickup can be improved.

When a plurality of light sources having different wavelengths of light are used in the related art, a quarter-wave plate, which had to be provided for each light source, can be combined into one, thereby reducing the number of parts. Since the number of assembling and positioning steps can be reduced, the productivity of the optical pickup can be improved. Further, even if the accuracy of the mounting position of the quarter-wave plate 333 is lower than that in the case where a plurality of the quarter-wave plates 333 are provided, the predetermined optical characteristics can be satisfied. Thus, an optical pickup having a high yield can be obtained.

Also, by using such a composite optical member 90, the alignment step at the time of assembling the optical pickup can be further simplified, and the occurrence of positional deviation can be suppressed more effectively. Also, the aberration correction means 332 and 1
Since the 波長 wavelength plate 333 can be formed as one member, it is possible to eliminate the necessity of alignment and the like as compared with a case where the 波長 wavelength plates 333 are separately formed, and the rate of change due to both operating conditions is almost the same. Therefore, the operating conditions can be made more uniform. In addition, it is easy to arrange the wiring used to supply power to both, and the wiring can be configured by the same FPC (flexible printed circuit), so that the number of components can be reduced. In addition, by forming electrodes on both surfaces of the substrate 330, the productivity of the quarter-wave plate and the aberration corrector can be improved. Further, the space utilization efficiency can be improved as compared with the case where they are separately configured.

Although the composite optical member 90 is provided separately from the first optical member 72 and the second optical member 86 here,
It may be provided integrally with the first optical member 72 or the second optical member 86, or may be formed directly in the first optical member 72 or the second optical member 86.

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

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

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

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

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

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

With this 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.

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

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

In this embodiment, the light source 2 and the light source 9 are arranged on the light source mounting portion 71. As described above, the plurality of light sources 2 and 9 are provided on the same light source mounting portion 71, so that the light sources 2 and 9 are fixed in a positional relationship determined in advance 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 can be reduced. Can be improved. Light source 2
In addition, a displacement between the light source 9 and the first optical member 72 hardly occurs, so that 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. Compared to the case, the connection between the light source 2 and the light source 9 and an electrode for supplying power to the light source or a wire used for connection to the ground can be easily performed. Light source 2
In addition, relative positioning with respect to the light source 9 can be performed more easily and accurately.

[0365] The surface of the light source mounting portion on which the light source is mounted needs to be exposed with extremely high precision. 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 high-density optical disk 18, recording or reproduction is performed using the light emitted from the light source 2. In this case, the light emitted from the light source 2 is first reflected by the reflection film 73 formed on the first slope 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.

After that, the light emitted from the first optical member 72 passes through the shield member 85, passes through the first substrate 86a of the second optical member 86, and then passes through the second substrate of the second optical member 86.
Filter 8 formed on second slope 86e of substrate 86b
9 and exits from the second optical member 86 and enters the composite optical member 90. The light incident on the composite optical member 90 is subjected to aberration correction corresponding to the warpage of the disk in advance, and the polarization direction is converted from linearly polarized light to elliptically polarized light, and then emitted from the composite optical member 90.

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

The light reflected by the high-density optical disk 18 and returned returns to the composite optical member 90 again. When this light is reflected by the high-density optical disk 18, the rotation direction of the elliptically polarized light is opposite to that at the time of incidence. The light is converted into linearly polarized light substantially orthogonal to the polarization direction of the outgoing light. That is, light emitted as S-polarized light when emitted from the light source 2 is incident on the second optical member 86 as P-polarized light.

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

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

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

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

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

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

[0377] Thereafter, the light emitted from the light source 9 enters the composite optical member 90. The light incident on the composite optical member 90 is subjected to aberration correction for coma aberration generated by disc tilt in advance, and its polarization direction is converted from linearly polarized light to elliptically polarized light and emitted from the composite optical member 90.

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

The light reflected by the low-density optical disc 19 and returned returns to the composite optical member 90 again. When this light is reflected by the low-density optical disk 19, the direction of rotation of the elliptically polarized light is opposite to that at the time of incidence. The light is converted into linearly polarized light substantially orthogonal to the polarization direction of the outgoing 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 composite optical member 90 is incident on 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 inclined member 86b. The light enters the multiple beam forming means 88 provided at 86d. In this case, since the polarization direction of the incident light is substantially orthogonal to the outgoing light, the incident light is reflected by the polarization separation film 88a almost without entering the beam separation unit 88b, Second substrate 86
b, and enters the diffusion angle conversion means 87 formed on the first substrate 86a.

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

Then, the second inclined surface 72 of the first optical member 72
b enters the polarization separation film 76. At this time, 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 splitting film 76 and splits the optical path formed on the third inclined surface 72c. The light enters the means 84. By this optical path dividing means 84, approximately half of the incident light is transmitted and approximately half is reflected.

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

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

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

As described above, in the present embodiment, the light source 2 is provided on the side 71a of the light source mounting portion 71.
And the light source 9 are disposed at substantially the same height from the bottom surface of the light source mounting portion 71. That is, a straight line connecting the light emitting point 2a of the light source 2 and the light emitting point 9a of the light source 9 is substantially perpendicular to the surface of the recording medium.

With this arrangement, the first plane including the optical axis formed when the light emitted from the light source 2 passes through the first optical member 72, and the light emitted from the light source 9 A second plane including an optical axis formed when passing through the first optical member 72 and a third plane including an optical axis formed when light emitted from the light source 9 passes through the second optical member 86 It can be used as a light propagation surface. In other words, not only the plane perpendicular to or parallel to the surface of the recording medium is used as the propagation plane, but any plane can be used as the propagation plane.

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

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

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

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

(Embodiment 5) Next, Embodiment 5 of the present invention will be described with reference to the drawings.

FIG. 18 is a diagram showing a configuration of an optical pickup device according to Embodiment 5 of the present invention, and FIG. 19 is a cross-sectional view of an aberration correcting means and a 波長 wavelength plate according to Embodiment 5 of the present invention. is there.

In FIG. 18, reference numerals 300 and 301 denote light source packages, and the light sources 2 and 9 described in the first embodiment are mounted inside the light source packages 300 and 301, respectively. Are linearly polarized light polarized in predetermined directions. Light emitted from the light source packages 300 and 301 is different from the optical disc 31 of a different type.
Irradiated at 0,311 and used for writing and reading information.

[0395] Both 302 and 303 are collimator lenses, and the collimator lenses 302 and 303 have a function of converting light emitted from the light source packages 300 and 301 into substantially parallel light, respectively.

Numerals 304 and 305 denote polarization split beam splitters.
Are set so as to transmit the linearly polarized light emitted from the light source packages 300 and 301 and reflect the linearly polarized light in a direction orthogonal thereto.

Reference numeral 306 denotes a beam splitter. It is preferable that the beam splitter 306 almost transmits the light emitted from the light source package 300 and reflects almost the light source package 301 in order to improve the light use efficiency. In order to satisfy such characteristics, it is necessary to use a wavelength filter using a difference in wavelength between the light source 2 and the light source 9 or a polarization separation filter using a difference in polarization direction between the light source 2 and the light source 9. Is preferable because the light can be guided without substantially reducing the light emission. Also, it is naturally possible to use a half mirror as the beam splitter 306.

Numeral 307 denotes an aberration correcting means.
Reference numeral 07 denotes a device capable of controlling the wavefront of light passing therethrough, and various configurations are conceivable. Here, the configuration using a liquid crystal will be described. In FIG. 19, 320
Is a liquid crystal, and the amount of twist of the liquid crystal 320 changes according to the applied voltage.

Reference numerals 321 and 322 denote substrates.
It is preferable that both materials 322 have a certain degree of hardness, such as glass, and use a material having a transmittance of about 90% or more with respect to the frequency of the incident light because a reduction in the amount of light can be suppressed.

[0400] The electrodes 3 for applying a voltage to the liquid crystal 320 are provided on the surfaces of the substrates 321 and 322 facing the liquid crystal 320.
21a and 322a are formed. This electrode 321
Both a and 322a are preferably divided into a plurality of portions so that the wavefront can be corrected in a wider range.

Reference numeral 323 denotes a power source.
a, 322a is applied with a predetermined voltage. By controlling this voltage, the wavefront of the passing light can be controlled. Therefore, by correcting the wavefront of the light passing therethrough in advance so as to cancel the coma caused by the tilt, the amount of the aberration such as the coma caused by the tilt can be suppressed to the minimum. . When the electrodes are provided separately, the voltage applied to each electrode can be made different to control the wavefront of the passing light more finely, and the coma generated by the disc tilt can be reduced. It can be removed more efficiently.

Further, the aberration correction means 307
It is preferable to control the wavefront for the light emitted from any of the above. Therefore, it is necessary to change the control of the voltage applied between the liquid crystal electrodes depending on which of the light sources 2 and 9 the light is emitted. Therefore, control means (not shown) for controlling the power supply 323 for applying a voltage to the electrodes 321a and 322a of the aberration correction means 307
Power supply 32 based on the information of which one is emitting light.
3 is preferably controlled. Thereby, the light sources 2, 9
Optimum wavefront control can be performed for light from any of the above. Information on which of the light sources 2 and 9 is emitting light can be obtained by, for example, a control unit (not shown) of the light sources 2 and 9.
May be based on a signal from a disc determination unit (not shown) for detecting which type of optical disc is set, or may use other known methods. Good.

Numeral 308 denotes a 板 wavelength plate, and １ ／ wavelength plate 3
Reference numeral 08 has a function of converting light that has entered as linearly polarized light into elliptically polarized light. Convert to Here, in particular, the quarter-wave plate 3
08 is composed of liquid crystal. The configuration will be described with reference to FIG.

In FIG. 19, reference numeral 324 denotes a liquid crystal.
In No. 4, the amount of twist changes in accordance with the applied voltage.

Reference numerals 325 and 326 denote substrates.
Electrodes 325a and 326a for applying a voltage to the liquid crystal 324 are formed on the surface of the side 326 facing the liquid crystal 324. The electrodes 325a and 326a are preferably formed according to the diffusion angle of the incident light. That is, when the incident light is parallel light, it is undivided, the diffusion angle is large, and when the transmitted light has a long distance to pass through the liquid crystal 324, the amount of twist decreases as it goes to the periphery. It is preferable to divide the electrodes to optimize the applied voltage.

Reference numeral 327 denotes a power supply.
a, 326a is applied with a predetermined voltage. By controlling this voltage, the phase of light passing in a specific direction can be shifted by ４ wavelength, and the incoming linearly polarized light is converted into circularly polarized light. can do.

Further, the 波長 wavelength plate sets the phase of light in a specific direction to 1 for light emitted from any of the light sources 2 and 9.
It is preferable to shift by / 4 wavelength. For this reason, depending on which of the light sources 2 and 9 the light is emitted from,
It is necessary to change the control of the voltage applied between the electrodes 325a and 326a. Therefore, a control means (not shown) for controlling the power supply 327 for applying a voltage to the electrodes 325a and 326a of the quarter-wave plate 308 uses a power supply 327 based on information on which of the light sources 2 and 9 is emitting light. Is preferably controlled. Thereby, optimal wavefront control can be performed for light from any of the light sources 2 and 9.
Information on which of the light sources 2 and 9 is emitting light is:
For example, it may be based on a signal from a control unit (not shown) of the light sources 2 and 9 or based on a signal from a disc determination unit (not shown) for detecting which type of optical disc is set. Alternatively, other known methods may be used.

[0408] Thus, by optimally controlling the voltage applied to the liquid crystal according to the wavelength of the incident light, the light emitted from both the light sources 2 and 9 can be accurately controlled. Since the phase can be shifted by ４ wavelength, any incident light can be reliably converted from the incident linearly polarized light into circularly polarized light, and the light reflected from the optical disks 310 and 311 can be converted to the original light. Can be reliably converted to linearly polarized light orthogonal to the linearly polarized light.
Since the use efficiency of any light emitted from the light sources 2 and 9 can be improved, the output of each of the light sources 2 and 9 can be used in a low state, so that power consumption can be reduced. At the same time, the life of the light sources 2 and 9 can be prolonged, and the reliability of the optical pickup can be improved.

When a plurality of light sources having different wavelengths of light are used in the past, a quarter-wave plate that had to be provided for each light source can be combined into one, thereby reducing the number of parts. Since the number of assembling and positioning steps can be reduced, the productivity of the optical pickup can be improved. Further, even if the accuracy of the mounting position of the quarter-wave plate 308 is lower than that in the case where a plurality of the quarter-wave plates 308 are provided, the predetermined optical characteristics can be satisfied. Thus, an optical pickup having a high yield can be obtained.

As described above, the beam splitters 304 and 30
It is preferable to use a polarization-separation type 5 and use it in combination with the quarter-wave plate 308, since the light use efficiency is improved and recording or reproduction can be performed on a plurality of types of optical disks. In addition, since the amount of light emitted from the light sources 2 and 9 can be suppressed, the life of the light sources 2 and 9 can be extended, and the reliability of the optical pickup device can be improved, which is preferable.

[0411] Reference numeral 309 denotes a condenser lens.
Is for converging both of the light emitted from the light sources 2 and 9 to form beam spots on the optical disks 310 and 311 respectively. The lens drive means (not shown) moves the lens in the focusing direction and the tracking direction. It is supported so that it can be moved.

Numerals 312 and 313 denote lenses, and lenses 312 and 313 denote beam splitters 304 and 3, respectively.
The light reflected at 05 is received by light receiving means 314, 3 respectively.
15 has a function of condensing light. In addition, in some cases, it has a function of forming a focus signal.

The light receiving means 314 and 315 have a function of forming an RF signal and a focus / tracking signal from the incident light.

Since the quarter-wave plate 308 is provided on the condenser lens 309 rather than the aberration correcting means 307, the light incident on the aberration correcting means 307 can be converted into linearly polarized light. The correction of the disc tilt by the means 307 can be performed more reliably, and the decrease in the amount of light in the aberration corrector 307 can be suppressed to a minimum.

[0415] Next, the operation of the optical pickup device having such a configuration will be described.

First, the outward light of the light emitted from the light source 2 will be described.

The light emitted from the light source 2 that emits light having the wavelength λ1 is converted into parallel light by the collimator lens 302, and most of the light passes through the beam splitter 304, and most of the light passes through the beam splitter 306. I do. Here, FIG. 20 is a schematic diagram showing a change in the polarization direction of light in one embodiment of the present invention. As shown in FIG. 20, light that has passed through the beam splitter 306 as linearly polarized light enters the aberration correction unit 307. Here, the aberration corrector 307 is formed by dividing the electrode 321a. The wavefront of the passing light is controlled by the aberration correcting means 307, and the wavefront of the passing light can be corrected in advance so as to cancel the coma generated by the disc tilt. Then, the linearly polarized light whose wavefront has been adjusted by the aberration corrector 307 enters the 波長 wavelength plate 308. Here, when a voltage is applied to the 板 wavelength plate 308, the molecules of the liquid crystal 324 are tilted in the direction of the electric field due to the electric field generated thereby, and optical anisotropy occurs in the direction of the electric field when viewed from the incident side. By arranging and controlling the quarter-wave plate 308 such that the direction of the optical anisotropy is inclined at approximately 45 degrees with respect to the linearly polarized light, the linearly polarized light is converted into circularly polarized light. Thereafter, the light converted into circularly polarized light is condensed by the condenser lens 309 and enters the optical disc 310.

Next, the return trip will be described.

[0419] A part of the light reflected by the optical disk 310 and having the information on the recording surface added thereto is converted from circularly polarized light into linearly polarized light in a direction orthogonal to the original polarization direction by the quarter-wave plate 308. Correction means 307 and beam splitter 306
And enters the beam splitter 304. Most of the light is reflected by the beam splitter 304, condensed by a lens 312, and incident on a light receiving unit 314, where an RF signal and a servo signal are formed.

Next, the outward path of the light emitted from the second light source 9 will be described.

The light emitted from the light source 9 that emits linearly polarized light having the wavelength λ2 is converted into parallel light by the collimator lens 303, and most of the light passes through the beam splitter 305, and most of the light is further converted by the beam splitter 306. The light is reflected and enters the aberration correction unit 307. The aberration correcting means 307 corrects the wavefront of the passing light so that the coma generated by the disc tilt is canceled. Then, the light whose wavefront has been adjusted by the aberration correcting means 307 is incident on the 波長 wavelength plate 308 and is converted from linearly polarized light into circularly polarized light. Thereafter, the light converted into circularly polarized light is condensed by a condenser lens 309 and is incident on an optical disc 311 different from the above-described optical disc 310.

Next, the return route will be described.

A part of the light reflected by the optical disk 311 and having the information on the recording surface added thereto is converted from circularly polarized light into linearly polarized light in a direction orthogonal to the original polarization direction by the quarter-wave plate 308, It passes through the correction means 307. After that, most of the light is reflected by the beam splitter 306 and enters the beam splitter 305. Most of the light is reflected by the beam splitter 305, condensed by the lens 313, and incident on the light receiving means 315, where an RF signal and a servo signal are formed.

(Embodiment 6) Next, an optical pickup module equipped with the optical pickup described in Embodiments 1 to 5 will be described.

FIG. 12 is a front view of an optical pickup module according to Embodiment 6 of the present invention. In FIG. 12, reference numeral 101 denotes a disk. In this embodiment, the disk 101 is a digital video disk (hereinafter referred to as a DV).
D) or a low-density optical disk 19 such as a compact disk (hereinafter abbreviated as CD).
Is used. Here, the high-density optical 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 section for recording or reproducing data on or from the disk 101. The optical portion has the configuration 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 unit 103, the optical pickup unit shown in Embodiment Modes 2 to 4 can be used.

A feed unit 104 moves 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.

[0431] 106 and 107 are spindle motor units 10
2 and a flexible substrate that supplies power to the optical pickup unit 103.

The operation of the optical pickup module having the above configuration will be described.

When a command to reproduce data existing at a predetermined position on the disk 101 being rotated by the spindle motor unit 102 is sent from the CPU, first, the condenser lens 17 is pulled in by the actuator 108. The feed unit 104 is driven to emit light from the light source 2 or the light source 9 to the disk 101, and the optical pickup unit 103 is moved to a track where predetermined data exists while confirming its position.

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

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

In the optical pickup module having such a configuration, since the optical pickup section 103 having the configuration shown in the first to fifth embodiments is used, the size and thickness of the optical pickup module can be reduced. In addition, since coma due to tilt or the like of the disk 101 can be reliably corrected, an optical pickup module having excellent optical characteristics can be obtained.

[0437]

As described above, the present invention has the following features.
By disposing the 波長 wavelength plate between the aberration correcting means and the recording medium, a small optical pickup capable of performing accurate tilt correction while improving light use efficiency and reducing power consumption. Can be provided.

Also, the ま た wavelength plate and the aberration correction means are configured to correspond to light from a plurality of light sources having different wavelengths, thereby reducing these separately required optical elements. As a result, the productivity of the optical pickup can be improved, and the occurrence of a process defect due to a displacement or the like can be suppressed.

[Brief description of the drawings]

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

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

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

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

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

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

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

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

FIG. 9 is a sectional view showing an optical path according to a third embodiment 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 sectional view showing an optical path according to a fourth embodiment of the present invention.

FIG. 12 is a front view of an optical pickup module according to Embodiment 6 of the present invention.

FIG. 13 is a schematic diagram showing a configuration of a conventional optical pickup.

FIG. 14 is an enlarged view of the vicinity of a light source according to the second embodiment of the present invention.

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

FIG. 16 is an enlarged view near a light source according to a third embodiment of the present invention.

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

FIG. 18 is a diagram showing a configuration of an optical pickup device according to a fifth embodiment of the present invention.

FIG. 19 is a sectional view of an aberration correction unit and a quarter-wave plate according to an embodiment of the present invention.

FIG. 20 is a schematic diagram illustrating a change in the polarization direction of light according to an embodiment of the present invention.

FIG. 21 is a sectional view of a composite optical member according to an embodiment of the present invention.

FIG. 22 is a front view showing an electrode configuration of an aberration correction unit according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 First package 1a Substrate part 1b Side wall part 1d Opening 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 8d Opening 9 Light source 10 Light receiving element 11 Second optical member 11a First slope 11b Second slope 12 Optical path dividing means 13 Reflecting means 15 Optical path dividing means 16 Collimator lens 17 Condensing lens 18 High density optical disc 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 means 24 Filter 25 Polarization separation Film 27 Diffusion angle conversion means 28 Multiple beam forming means 29 Reflecting means 3 0 Reflecting means 31 Diffusion angle converting means 32 Signal forming means 33 Light receiving means 34 Light source mounting part 34a Surface 35 Reflecting member 35a, 35b, 35c surface 40 Package 40a Substrate part 40b Side wall part 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 Reflecting film 45, 46 Polarization separating film 47 Second optical member 48 Diffusion angle converting means 49 Third optical member 49a First inclined surface 49b Second slope 50 Multiple beam forming means 50a Polarization separation film 50b Beam separation unit 51 Filter 53 Fourth optical member 53a First slope 53b Second slope 54,55 Optical path splitting means 56,57 Reflective film 58,59 Light receiving means 60, 61 Reflecting member 60a surface 61a surface 70 Package 70a Substrate 70b side Unit 70c terminal 70d opening 71 light source mounting unit 71a surface 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 Reflecting portion 81, 82 Reflecting film 83, 84 Optical path dividing 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 beams Forming unit 88a Polarization separating film 88b Beam separating unit 89 Filter 90 Composite optical member 91 Light receiving unit 92 Light receiving unit 93 Reflecting member 93a, 93b Surface 101 Disk 102 Spindle motor unit 103 Optical pickup unit 104 Feed unit 105 Module base 106, 107 Flexible substrate 108 Acti Eta 300, 301 Light source package 302, 303 Collimator lens 304, 305 Beam splitter 306 Beam splitter 307 Aberration correction means 308 Quarter-wave plate 309 Condensing lens 310, 311 Optical disc 312, 313 Lens 314, 315 Light receiving means 320 Liquid crystal 321 322 substrate 321a, 322a electrode 323 power supply 324 liquid crystal 325, 326 substrate 325a, 326a electrode 327 power supply 329, 330, 331 substrate 329a, 330a, 330b, 331a electrode 332 aberration correction means 333 quarter wave plate 334, 335 power supply A light flux B luminous flux C1, C2, D1, D2, E1, E2 split electrode

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Takashi Haruguchi 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Mitsuyoshi Kojima 1006 Kazama Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Hiroshi Goto 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term (reference) 5D119 AA41 AA43 BA01 CA09 DA01 DA05 EC45 EC47 FA05 JA09 JA32 JA43 JB03 KA02 LB05

Claims (45)

[Claims] A light source for emitting linearly polarized light; a light condensing means for converging incident light on a recording medium; and an aberration correcting means for correcting aberration of a light beam incident on the light condensing means. An optical pickup characterized in that aberration of a light beam emitted from a light condensing means is controlled only by the aberration correcting means. 2. The optical pickup according to claim 1, wherein the aberration correcting means includes a liquid crystal, and a first light-transmitting substrate and a second light-transmitting substrate sandwiching the liquid crystal. 3. The optical pickup according to claim 2, wherein a first transparent electrode is formed on the first light transmitting substrate, and a second transparent electrode is formed on the second light transmitting substrate. . 4. The optical pickup according to claim 3, wherein at least one of the first transparent electrode and the second transparent electrode is divided into at least two or more regions. 5. A light receiving means for converting optical information from a recording medium into an electric signal, wherein said aberration correcting means is controlled based on information from said light receiving means. 1. The optical pickup according to 1. 6. A light source for emitting linearly polarized light, a quarter-wave plate for changing the polarization state of the linearly polarized light, a light condensing means for condensing incident light on a recording medium, and a light condensing means. An optical pickup, comprising: aberration correction means for correcting aberration of an incident light beam; wherein the quarter-wave plate is provided between the aberration correction means and the recording medium. 7. The optical pickup according to claim 6, wherein the aberration correcting means includes a liquid crystal, and a first light-transmitting substrate and a second light-transmitting substrate sandwiching the liquid crystal. 8. The optical pickup according to claim 7, wherein a first transparent electrode is formed on the first light-transmitting substrate, and a second transparent electrode is formed on the second light-transmitting substrate. . 9. The optical pickup according to claim 8, wherein at least one of the first transparent electrode and the second transparent electrode is divided into at least two or more regions. 10. A light receiving means for converting optical information from a recording medium into an electric signal, and a control means for controlling an operation of the aberration correcting means based on information from the light receiving means. The optical pickup according to claim 6. 11. The optical pickup according to claim 6, wherein the quarter-wave plate is made of liquid crystal. 12. A light receiving means for converting optical information from a recording medium into an electric signal, and control means for controlling the operation of a quarter-wave plate based on the information from said light receiving means. The optical pickup according to any one of claims 6 and 11, wherein: 13. An optical pickup according to claim 6, wherein both the aberration correcting means and the quarter-wave plate are made of liquid crystal. 14. An optical pickup according to claim 6, wherein the aberration correcting means and the quarter-wave plate are integrated. 15. An integrated aberration correcting means and a quarter wavelength plate, comprising a first substrate, a second substrate and a third substrate, wherein the first substrate, the second substrate and Wherein a first liquid crystal serving as the aberration correcting means is provided between the first and second substrates, and a second liquid crystal serving as the 波長 wavelength plate is provided between a second substrate and a third substrate. Item 15. An optical pickup according to Item 14. 16. The optical pickup according to claim 15, wherein each of the first substrate, the second substrate, and the third substrate is formed of a translucent material. 17. The method according to claim 1, wherein transparent electrodes are formed on the first substrate, the second substrate, and the third substrate, respectively, on the surface facing the first liquid crystal or the second liquid crystal.
An optical pickup according to any one of claims 5 and 16. 18. A method according to claim 18, wherein at least one of the transparent electrodes formed on the first substrate, the second substrate and the third substrate is a transparent electrode divided into at least two or more regions. Item 18. An optical pickup according to Item 17. 19. The apparatus according to claim 1, further comprising: first control means for controlling the operation of the liquid crystal of the aberration correcting means; and second control means for controlling the operation of the liquid crystal of the quarter-wave plate. Fifteen
20. The optical pickup according to any one of items 18 to 18. 20. At least one of the first control means and the second control means operates based on information from light receiving means for converting optical information from a recording medium into an electric signal. Item 20. An optical pickup according to item 19. 21. An apparatus according to claim 6, wherein the aberration of the light beam emitted from the light source is controlled only by the aberration correcting means.
0. The optical pickup according to any one of 1. 22. A first light source for emitting linearly polarized light, a second light source for emitting light having a wavelength different from that of the first light source, and a light condensing means for condensing incident light on a recording medium. When,
An aberration corrector for correcting an aberration of at least one of a light beam emitted from the first light source and a light beam emitted from the second light source incident on the light collector. Optical pickup. 23. An optical pickup according to claim 22, wherein said aberration correcting means comprises a liquid crystal, and a first light-transmitting substrate and a second light-transmitting substrate sandwiching said liquid crystal. 24. A first transparent electrode on a first translucent substrate,
The optical pickup according to claim 23, wherein a second transparent electrode is formed on the second translucent substrate. 25. The optical pickup according to claim 24, wherein at least one of the first transparent electrode and the second transparent electrode is divided into at least two or more regions. 26. A first split electrode divided into at least one of a first transparent electrode and a second transparent electrode into a shape suitable for correcting aberration of light emitted from a first light source;
26. The optical pickup according to claim 24, wherein a second divided electrode divided into a shape suitable for correcting aberration of light emitted from the second light source is formed. 27. A first transparent electrode comprising: a first split electrode divided into a shape suitable for correcting aberration of light emitted from a first light source; and an aberration of light emitted from a second light source. A second divided electrode divided into a shape suitable for correction, and
The second transparent electrode has a third divided electrode divided into a shape suitable for correcting aberration of light emitted from the first light source, and a shape suitable for correcting aberration of light emitted from the second light source. And when the first light source is used, the potential difference between the second divided electrode and the fourth divided electrode is substantially zero, and the fourth divided electrode is divided into two. 3. A light source according to claim 2, wherein the potential difference between said first divided electrode and said third divided electrode is substantially zero.
The optical pickup according to any one of 4, 25. 28. A light-receiving device comprising: light-receiving means for converting optical information from a recording medium into an electric signal; and control means for controlling the operation of the aberration correction means based on the information from the light-receiving means. An optical pickup according to any one of claims 22 to 27. 29. An apparatus according to claim 22, wherein the aberration of the light beam traveling from at least one of the first light source and the second light source toward the recording medium is controlled only by the aberration correcting means.
An optical pickup according to any one of the above. 30. A first light source that emits linearly polarized light, a second light source that emits light having a wavelength different from that of the first light source, light emitted from the first light source, A 波長 wavelength plate for converting the polarization state of at least one of the light emitted from the second light source, a light condensing means for condensing incident light on a recording medium, and the first light source or the first light source. Aberration correction means for correcting at least one aberration of light traveling from the second light source toward the recording medium, and the 波長 wavelength plate is provided between the aberration correction means and the light condensing means. An optical pickup that features. 31. The optical pickup according to claim 30, wherein the aberration correcting means includes a liquid crystal, and a first light-transmitting substrate and a second light-transmitting substrate sandwiching the liquid crystal. 32. A first transparent electrode on a first translucent substrate,
The optical pickup according to claim 31, wherein a second transparent electrode is formed on the second translucent substrate. 33. The optical pickup according to claim 32, wherein at least one of the first transparent electrode and the second transparent electrode is divided into at least two or more regions. 34. A first divided electrode divided into a shape suitable for correcting aberration of light emitted from a first light source, at least one of a first transparent electrode and a second transparent electrode;
34. The optical pickup according to claim 32, wherein a second divided electrode divided into a shape suitable for correcting aberration of light emitted from the second light source is formed. 35. A first transparent electrode comprising: a first split electrode divided into a shape suitable for correcting aberration of light emitted from a first light source; and an aberration of light emitted from a second light source. A second divided electrode divided into a shape suitable for correction, and
The second transparent electrode has a third divided electrode divided into a shape suitable for correcting aberration of light emitted from the first light source, and a shape suitable for correcting aberration of light emitted from the second light source. And when the first light source is used, the potential difference between the second divided electrode and the fourth divided electrode is substantially zero, and the fourth divided electrode is divided into two. 4. The device according to claim 3, wherein when the light source is used, a potential difference between the first and third divided electrodes is substantially zero.
An optical pickup according to any one of 2, 33. 36. A light receiving means for converting optical information from a recording medium into an electric signal, and a control means for controlling an operation of said aberration correcting means based on the information from said light receiving means. The optical pickup according to claim 34,35. 37. The optical pickup according to claim 31, wherein the quarter-wave plate is made of liquid crystal. 38. The optical pickup according to claim 31, wherein both the aberration correcting means and the quarter-wave plate are formed of liquid crystal. 39. An optical pickup according to claim 31, wherein the aberration correcting means and the quarter-wave plate are integrated. 40. An integrated aberration correcting means and a quarter-wave plate, comprising a first substrate, a second substrate and a third substrate, wherein the first substrate and the second substrate A first liquid crystal that operates as the aberration correction unit between the first and second substrates, and a second liquid crystal that operates as the 波長 wavelength plate is provided between a second substrate and a third substrate. An optical pickup according to claim 39. 41. The optical pickup according to claim 40, wherein the first substrate, the second substrate, and the third substrate are each formed of a translucent material. 42. A transparent electrode is formed on the first substrate, the second substrate, and the third substrate on the side facing the first liquid crystal or the second liquid crystal. Optical pickup. 43. The optical pickup according to claim 42, wherein at least one of the transparent electrodes of the first substrate and the second substrate is divided into at least two or more regions. 44. A liquid crystal display comprising: first control means for controlling a first liquid crystal operating as an aberration correcting means; and second control means for controlling a second liquid crystal operating as a quarter-wave plate. The optical pickup according to claim 38, wherein: 45. A light receiving means for converting optical information from a recording medium into an electric signal, wherein at least one of the first control means and the second control means is controlled based on the information from the light receiving means. 43. The optical pickup according to claim 42, wherein: