GB2312547A - Optical pickup device mounted on silicon substrate - Google Patents
Optical pickup device mounted on silicon substrate Download PDFInfo
- Publication number
- GB2312547A GB2312547A GB9708506A GB9708506A GB2312547A GB 2312547 A GB2312547 A GB 2312547A GB 9708506 A GB9708506 A GB 9708506A GB 9708506 A GB9708506 A GB 9708506A GB 2312547 A GB2312547 A GB 2312547A
- Authority
- GB
- United Kingdom
- Prior art keywords
- prism
- laser beam
- optical
- transmitting
- silicon substrate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1359—Single prisms
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1353—Diffractive elements, e.g. holograms or gratings
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/123—Integrated head arrangements, e.g. with source and detectors mounted on the same substrate
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1372—Lenses
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1372—Lenses
- G11B7/1378—Separate aberration correction lenses; Cylindrical lenses to generate astigmatism; Beam expanders
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B2007/0003—Recording, reproducing or erasing systems characterised by the structure or type of the carrier
- G11B2007/0006—Recording, reproducing or erasing systems characterised by the structure or type of the carrier adapted for scanning different types of carrier, e.g. CD & DVD
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Optical Head (AREA)
- Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
- Optical Recording Or Reproduction (AREA)
Abstract
A simple and compact optical pickup device comprises a silicon substrate 110, disposed parallel with an optical disc 180 and having prism 160 installed thereon. The beam from laser 130, also supported on the substrate, is reflected by beam splitter 161, positioned inside the prism, after being transmitted through diffraction grating 140, formed on a side of the prism. The reflected beam focuses onto the optical disc 180 via a selective light-transmitting part 150 formed on the upper surface of the prism. The beam is totally transmitted through an inner circular portion 151 of the selective light-transmitting part, and half transmitted through a peripheral portion 152 so that double beam focuses of different sizes can be formed. The beam reflected from the optical disc is received by photodetector 190 formed on an upper surface of the prism. Because all the optical components are fixed with respect to the substrate, their relative disposition remains fixed.
Description
OPTICAL PICKUP DEVICE
The present invention relates to an optical pickup device, for example, to an optical pickup device with optical constituents which are integrally manufactured.
Information reproducing/recording systems for using optical discs such as laser discs or compact discs have been developed in recent years. Such optical.
information reproducing/recording systems reproduce/record a variety of information.
A digital audio disc player for reproducing musical sounds and a digital video disc player for reproducing images serve as examples. It is the trend that the recording media of these optical information reproducing/recording systems has higher densities for making discs more compact and smaller, and also the disc players of these optical information reproducing/recording systems are more compacted and miniaturized. Also, the compatible systems are developed such as the recording of
High Definition Television (H Dm1) compatible video discs.
A construction and operation of a general optical pickup device is disclosed in
U.S.- A - 4,767,921 or 4,868,377.
The conventionally general optical pickup device will be described in detail with reference to Figure 1 below.
Figure 1 is a schematic view showing the conventionally general optical pickup device. In Figure 1, a reference numeral 11 denotes a light source for generating laser beam, which is a laser diode 11. The laser beam emitted from laser diode 11 is diffracted while transmitting through a diffraction grating 12. The diffracted beam proceeds toward a beam splitter 13.
Here, beam splitter 13 is provided in such a manner that two right-angled prisms are installed to oppose to each other against respective inclination planes of 45 , and a coating layer 13a is formed along the contacting portion of the prisms, thereby transmitting some of the incident beam and reflecting the other incident beam to be perpendicular to the incident beam while securing the property of travelling straight of the incident beam.
The diffracted beam is reflected toward optical disc 15 by means of beam splitter 13. The beam reflected from beam splitter 13 focuses onto a recording plane 15a of an optical disc 15 while passing through an objective lens 14 installed in front of a recording medium such as optical disc 15. A positional accuracy, i.e., focusing error and tracking error, of the pickup device with respect to optical disc 15 is detected from an image of the beam received into a photodetector 16, and therefore, the focusing and tracking are controllable. Also, the information is read out on the basis of the amount of the reflected light determined by pits in recording plane 1 5a of optical disc 15.
Meantime, in the above-mentioned conventional optical pickup device, since such optical components as the beam splitter, the diffraction grating, the laser diode, and the photodetector should be individually manufactured and respectively located at their accurate positions, manufacturing and controlling of the optical pickup device are very difficult. Also, the optical pickup device and the optical disc player need to be compacted and miniaturized to act up to the recent trend relating to the optical disc player.
Furthermore, according to the conventional optical pickup device, discs of two different kinds can not be reproduced or recorded by means of a single optical pickup device. For example, if the recording capacity of the disc is to be four times like that of the digital video disc as compared with the digital audio disc, the width of pits in the disc is consequently decreased by 1/2. For this reason, a focused spot size onto the digital video disc should be half of that onto the digital audio disc with the consequence of necessarily employing different optical pickup devices in reproducing the digital video disc and digital audio disc by means of the conventional optical pickup devices. That is, in order to accurately read out data respectively recorded on the digital audio disc and digital video disc, it is required to separately apply one optical pickup device for digital audio disc of which beam spot size is approximately 1.6calm when focusing onto the digital audio disc and another optical pickup device for digital video disc of which beam spot size is approximately 0.8pm when focusing onto the digital video disc.
It is an object of the present invention to provide an optical pickup device which is simplified or more compact than conventional devices.
According to a first aspect of the present invention, there is provided an optical pickup device for focusing a laser light beam onto an optical disc, said optical pickup device comprising a silicon substrate, and a number of optical components, wherein said optical components are fixed with respect to said silicon substrate whereby the relative disposition thereof remains fixed.
An optical pickup device of an embodiment of the invention is capable of reproducing discs of two kinds having different densities by forming double beam focuses of different sizes.
The invention also extends to an optical pickup device which comprises a silicon substrate disposed parallel with an optical disc and provided with optical components thereon. A prism for transmitting an incident beam is disposed on the silicon substrate. A laser light source part has a laser light source for generating laser beam, the laser light source part being spaced out from the prism on the silicon substrate. A diffraction grating for diffracting an laser beam irradiated from the laser light source is formed on one side surface of the prism which faces the laser light source part. A beam splitter is for partially reflecting and partially transmitting the laser beam, the beam splitter being positioned inside of the prism to keep a predetermined angle with the silicon substrate, so that the laser beam irradiated from the laser light source is incident on the beam splitter after having transmitted through the diffraction grating, and then the beam is partially reflected by the beam splitter toward the optical disc which is to be positioned at upper part of the silicon substrate.
A reflecting layer is formed on a lower surface of the prism to reflect the laser beam partially transmitting the beam splitter after being reflected from the optical disc. A light-receiving part is formed on an upper surface of the prism to receive the laser beam reflected by the reflecting layer. An objective lens is disposed between the prism and the optical disc for permitting the laser beam to focus on the disc via the prism.
The reflecting layer of the prism is integrally provided with a Fresnel lens for shortening the optical distance.
The side surface of the prism on which the diffracting grating is installed can be integrally provided with a Fresnel lens for shortening the optical distance.
The optical pickup device further comprises a selective light-transmitting part formed on an upper surface of the prism for transmitting the laser beam proceeding to the disc after being reflected by the beam splitter. The selective light-transmitting part has an inner circular part for transmitting the laser beam with a first transmittance and a peripheral portion for transmitting the laser beam with a second transmittance.
The first transmittance is higher than the second transmittance. Preferably, the inner circular portion is a totally transmitted one of which the transmittance is 1 and the peripheral portion is a half transmitted one of which the transmittance is 1/2.
A difference between spot sizes focusing on the disc is adjustable by properly regulating an outermost angle of incidence of the laser beam which is transmitted through the inner circular portion of the selective light-transmitting part.
In an optical pickup device as defined above, in which such optical components as the beam splitter, the diffraction grating, the laser diode, and the photodetector may be integrally manufactured, and fixed at their accurate positions in the manufacturing process, manufacturing and controlling of the optical pickup device are very simple.
Also, the optical pickup device may be compacted and miniaturized by employing such a component as Fresnel lens for shortening the optical distance.
In an optical pickup device as defined above, when the laser beam transmits through the selective light-transmitting part, the laser beam having transmitted through the inner circular portion forms the larger beam spot onto the disc and the laser beam having transmitted through the peripheral portion forms the smaller beam spot. By doing so, double beam focuses of different sizes can be formed by the use of the single optical pickup device, thereby making it possible to reproduce discs of two types with different densities by means of the single optical pickup device.
As a result, in case of the digital audio disc and digital video disc having different recording capacities from each other, both discs can be reproduced when employing the optical pickup device according to the present invention.
Embodiments of the present invention will hereinafter be described, by way of example, with reference to the accompanying drawings, in which:
Figure 1 is a schematic view showing a conventional optical pickup device; and
Figure 2 is a schematic view showing an optical pickup device of to the present invention.
Figure 2 is a schematic view showing an embodiment of an optical pickup device of the invention. As shown in Figure 2, a silicon substrate 110 is disposed parallel with a recording plane 185 of an optical disc 180. Silicon substrate 110 is to be provided with optical components thereon. A prism 160 has a rectangular bar shape, and the opposite faces are parallel each other and the crossing faces are orthogonal.
Laser light source part 130 for transmitting an incident beam is installed at a position spaced out from prism 160 on silicon substrate 110. Laser light source part 130 has a laser diode 131 for generating laser beam and a supporting part 132 installed on silicon substrate 110 for seating laser diode 131 thereon. Supporting part 132 has a function for protecting against heat emitted from laser diode.
A diffraction grating layer 140 is formed on one side surface of prism 160 which faces the laser diode 131 for diffracting an laser beam irradiated from laser diode 131.
A beam splitter layer 161 for partially reflecting and partially transmitting the laser beam is formed inside of prism 160. Beam splitter layer 161 is slanted at an angle of 45" against diffraction grating layer 140 as well as the upper surface of prism 160. Thereby, the laser beam irradiated from laser diode 131 is incident with an angle of 45" on beam splitter 161 after having transmitted through diffraction grating 140, and then the beam is partially reflected with an angle of 45" from the beam splitter layer 161 toward optical disc 180 parallel to the upper part of silicon substrate 110.
A reflecting layer 165 is formed on a lower surface of prism 160. Furthermore, reflecting layer 165 is integrally provided with a Fresnel lens 166 for shortening the optical distance. Fresnel lens 166 is positioned on the optical path of laser beam partially transmitting beam splitter layer 161 after being reflected from optical disc 180.
A photodetector 190 is formed on an upper surface of prism 160 to receive the laser beam reflected by reflecting layer 165.
Furthermore, the side surface of prism 160 on which diffracting grating layer 140 is installed can be integrally provided with a Fresnel lens for shortening the optical distance.
A selective light-transmitting part 150 is integrally formed on an upper surface of prism 160 for transmitting the laser beam proceeding to disc 180 after being reflected by beam splitter layer 161. Selective light-transmitting part 150 consists of an inner circular portion 151 that transmits the laser beam with the first transmittance and a peripheral portion 152 that transmits the laser beam with the second transmittance. Selective light-transmitting part 150 may be preferably formed by a circular light-transmitting plate of which peripheral portion 152 is in the form of a ring.
The first transmittance is so determined as to be higher than the second transmittance. Preferably, inner circular portion 151 is a totally transmitted one, and peripheral portion 152 is a half transmitted one.
An objective lens 170 is installed between optical disc 180 and selective lighttransmitting part 150 for permitting the beam transmitted through selective lighttransmitting part 150 to focus onto a recording plane 185 of optical disc 180.
Objective lens 170 is an unspherical lens to minimize spherical aberration. Objective lens 170 is preferably a lens for DVD so that the beam having transmitted through selective light-transmitting part 150 can reproduce digital video disc (DVD) with 0.6mm thickness.
Hereinafter, an operation according to the foregoing embodiment will be described.
The laser beam is irradiated from laser diode 131 toward prism 160. The laser beam is divided into three beams while transmitting through diffraction grating layer 140 formed on the side surface of prism 160.
The divided beams are incident at the angle of 45" on beam splitter layer 160.
The laser beams are partially transmitted, and partially reflected to be bent by right angles with respect to the incident light by means of beam splitter layers 161. Then, the beams proceeds toward optical disc 180.
The beam passes through selective light-transmitting part 150 formed on the upper surface of prism 160. The beam totally transmits through inner circular portion 151 of selective light-transmitting part 150, and half transmits through peripheral portion 152 of selective light-transmitting part 150.
The transmitted beam is to focus onto recording plane 185 of optical disc 180 by means of objective lens for DVD 170 installed between optical disc 180 and prism 160.
At this time, the laser beam, which totally transmits through inner circular portion 151 of the circular light-transmitting plate 150, focuses onto optical disc 180 at an angle of 91 via objective lens 170. At the same time, the laser beam, which half transmits through peripheral portion 152 of circular light-transmitting plate 150, focuses onto optical disc 180 at an angle of 92 via objective lens 170 .
The laser beams focusing at the angles of 91 and 92 on the disc transmit through circular light-transmitting plate 150 via objective lens 170 to return to beam splitter 160. The returned beams having optical information partially transmit through coating layer 161 to be received into photodetector 190 installed to the lower portion of beam splitter 160, and are thus demodulated into original signals.
At this time, two different numerical apertures (N.A.) are produced by inner circular portion 151 and peripheral portion 152 of circular light-transmitting plate 150.
By these different two numerical apertures, two beam spots of different sizes are formed onto optical disc 180. Due to this fact, a difference appears in the quantities of light.
That is, N.A.1=nsin01 and N.A.2=sin92 (where n denotes a refractive index of a medium, and 9 is an angle formed between an optical axis and outermost incident beam).
At this time, a diameter of the beam W0 is written as: WO = K*7JN.A. (where K is a constant), and 2
Do (focal depth) = R*x/(N.A.)2 (where R is a constant).
Thus, along with the change of the numerical aperture, the beam size and focal depth become changed.
Therefore, the beam focusing by the outermost angle of incidence 92 after passing through peripheral portion 152 of circular light-transmitting plate 150 has smaller beam size and focal depth than those of the beam focusing by the outermost incident angle 91 by objective lens 170 after passing through inner circular portion 151. This is because the beam size is in inverse proportion to N.A. and the focal depth is in inverse proportion to (N.A.)2.
When optical disc 180 is of the digital video disc of thickness 0.6mm, the laser beam focusing on the optical disc via objective lens 170 after transmitting through light-transmitting plate 150 forms the beam spot of 0.8cm size onto optical disc 180.
Since the present objective lens is the lens for DVD, the beam can focus accurately without generation of spherical aberration on the recording surface of the digital video disc.
Meanwhile, when optical disc 180 is of the digital audio disc of thickness 1.2mm, since the beams on and close by the optical axis totally transmit through inner circular portion 151 of circular light-transmitting plate 150, and the beams in the skirts of the optical axis half transmit through peripheral portion 152 of circular lighttransmitting plate 150, the numerical aperture N.A. of the beam focusing onto the disc via objective lens 170 becomes smaller as N.A.1. Therefore, spherical aberration to be occurred due to the difference of 0.6mm in thickness as compared with the digital video disc is sharply decreased due to the smaller numerical aperture
N.A.1. Thus, digital audio disc with larger width of the pit can be reproduced.
That is, when reproducing digital audio disc, spherical aberration is to be occurred due to the difference of 0.6mm in thickness as compared with digital video disc.
At this time, the spherical aberration is (Ad/8)*{(n2 l 3}*(N A )4 (where Ad is a difference of thicknesses of the discs, TI is a refractive index of a medium, and N.A. is a numerical aperture)
Accordingly, the beams on and close by the optical axis which occur smaller spherical aberration totally transmit through inner circular portion 151 of circular lighttransmitting plate 150. Also, the beams which pass through the skirts of the lens occur larger spherical aberration and half transmit through peripheral portion 152 of circular light-transmitting plate 150. Thereby, the numerical aperture N.A. formed by the beam becomes smaller as N.A.1= sin01. Therefore the spherical aberration is sharply decreased in proportion to (N.A.)4. Also, since the numerical aperture becomes smaller as N.A.1= sin01, the size of beam spot formed on the disc is larger as 1.6pm in inverse proportion to (N.A.). Thus, digital audio disc with larger width of the pit can be reproduced.
In the optical pickup device as described above, optical components such as the beam splitter, the diffraction grating, the laser diode, and the photodetector should be integrally manufactured, and fixed at their accurate positions in manufacturing process, manufacturing and controlling of the optical pickup device are very simple.
Also, the optical pickup device can be compacted and miniaturized by employing such a component as Fresnel lens for shortening the optical distance.
In the optical pickup device as described above, when the laser beam transmits through the selective light-transmitting part, the laser beam having transmitted through the inner circular portion forms the larger beam spot onto the disc and the laser beam having transmitted through the peripheral portion forms the smaller and less light beam spot. By doing so, double beam focuses of different sizes can be formed by the use of the single optical pickup device, thereby making it possible to reproduce discs of two types with different densities by means of the single optical pickup device.
As a result, in case of the digital audio disc and digital video disc having different recording capacities from each other, both discs can be reproduced when employing the optical pickup device according to the present invention.
It will be appreciated that modifications to and variations in the embodiments as particularly described and illustrated may be made without departing from the scope of the invention as defined by the appended claims.
Claims (14)
1. An optical pickup device for focusing a laser light beam onto an optical disc,
said optical pickup device comprising a silicon substrate, and a number of
optical components, wherein said optical components are fixed with respect to
said silicon substrate whereby the relative disposition thereof remains fixed.
2. An optical pickup device as claimed in Claim 1, wherein said optical
components comprise a prism for transmitting an incident laser light beam,
said prism being disposed on said silicon substrate.
3. An optical pickup device as claimed in Claim 2, wherein said optical
components comprise further components formed on sides of said prism.
4. An optical pickup device as claimed in any preceding claim, wherein a laser
light source is disposed on said silicon substrate.
5. An optical pickup device comprising:
a silicon substrate disposed parallel with an optical disc and provided
with optical components thereon;
a prism for transmitting an incident beam disposed on the silicon
substrate;
a laser light source part having a laser light source for generating laser
beam, the laser light source part being spaced out from the prism on the
silicon substrate;
a diffraction grating for diffracting a laser beam irradiated from the laser
light source, the diffraction grating being formed on one side surface of the
prism which faces the laser light source part;
a beam splitter for partially reflecting and partially transmitting the laser
beam, the beam splitter being position inside of the prism to be slanted by a
predetermined angle on the silicon substrate, so that the laser beam irradiated
from the laser light source is incident on the beam splitter after having
transmitted through the diffraction grating, and then the beam is partially
reflected by the beam splitter toward the optical disc which is to be positioned
at upper part of the silicon substrate;
a reflecting layer formed on a lower surface of the prism, the reflecting
layer reflecting the laser beam partially transmitted through the beam splitter
after being reflected from the optical disc;
a light-receiving part formed on an upper surface of the prism for
receiving the laser beam reflected by the reflecting layer; and
an objective lens disposed between the prism and the optical disc for
permitting the laser beam to focus on the disc via the prism.
6. An optical pickup device as claimed in Claim 5, wherein the reflecting layer of
the prism is integrally provided with a Fresnel lens for shortening the optical
distance.
7. An optical pickup device as claimed in Claim 5 or Claim 6, wherein the side
surface of the prism on which the diffracting grating is installed is integrally
provided with a Fresnel lens for shortening the optical distance.
8. An optical pickup device comprising:
a silicon substrate disposed parallel with an optical disc and provided
with optical components thereon;
a prism for transmitting an incident beam disposed on the silicon
substrate;
a laser light source part having a laser light source for generating laser
beam, the laser light source part being spaced out from the prism on the
silicon substrate;
a diffraction grating for diffracting a laser beam irradiated from the laser
light source, the diffraction grating being formed on one side surface of the
prism which faces the laser light source part;
a beam splitter for partially reflecting and partially transmitting the laser
beam, the beam splitter being positioned inside of the prism to be slanted by a
predetermined angle on the silicon substrate, so that the laser beam irradiated
from the laser light source is incident on the beam splitter after having
transmitted through the diffraction grating, and then the beam is partially
reflected by the beam splitter toward the optical disc which is to be positioned
at upper part of the silicon substrate;
a selective light-transmitting part formed on an upper surface of the
prism for transmitting the laser beam proceeding to the disc after being
reflected by the beam splitter, the selective light-transmitting part having an
inner circular part for transmitting the laser beam with a first transmittance and
a peripheral portion for transmitting the laser beam with a second
transmittance;
a reflecting layer formed on a lower surface of the prism, the reflecting
layer reflecting the laser beam partially transmitted through the beam splitter
after being reflected from the optical disc;
a light-receiving part formed on an upper surface of the prism for
receiving the laser beam reflected by the reflecting layer; and
an objective lens disposed between the prism and the optical disc for
permitting the laser beam to focus on the disc via the prism.
9. An optical pickup device as claimed in Claim 8, wherein the first transmittance
is higher than the second transmittance.
10. An optical pickup device as claimed in Claim 8 or Claim 9, wherein the inner
circular portion is a totally transmitted one of which the transmittance is 1 and
the peripheral portion is a half transmitted one of which the transmittance is
1/2.
11. An optical pickup device as claimed in any of Claims 8 to 10, wherein the
selective light-transmitting part is comprised of a circular light-transmitting
plate of which peripheral portion is shaped as a ring.
12. An optical pickup device as claimed in any of Claims 8 to 11, wherein a
difference between spot sizes focusing on the disc is adjustable by properly
regulating an outermost angle of incidence of the laser beam which is
transmitted through the inner circular portion of the selective light-transmitting
part.
13. An optical pickup device comprising:
a silicon substrate disposed parallel with an optical disc and provided
with optical components thereon;
a prism for transmitting an incident beam disposed on the silicon
substrate;
a laser light source part having a laser light source for generating laser
beam, the laser light source part being spaced out from the prism on the
silicon substrate;
a diffraction grating for diffracting a laser beam irradiated from the laser
light source, the diffraction grating being formed on one side surface of the
prism which faces the laser light source part;
a beam splitter for partially reflecting and partially transmitting the laser
beam, the he beam splitter being positioned inside of the prism to be slanted
by a predetermined angle on the silicon substrate, so that the laser beam
irradiated from the laser light source is incident on the beam splitter after
having transmitted through the diffraction grating, and then the beam is
partially reflected by the beam splitter toward the optical disc which is to be
positioned at upper part of the silicon substrate;
a selective light-transmitting part formed on an upper surface of the
prism for transmitting the laser beam proceeding to the disc after being
reflected by the beam splitter, the selective light-transmitting part having an
inner circular part for totally transmitting the laser beam and a peripheral
portion for half transmitting the laser beam;
a reflecting layer formed on a lower surface of the prism, the reflecting
layer reflecting the laser beam partially transmitted through the beam splitter
after being reflected from the optical disc;
a Fresnel lens integrally formed on the reflecting layer of the prism for
shortening the optical distance;
a light-receiving part formed on an upper surface of the prism for
receiving the laser beam reflected by the reflecting layer; and
an objective lens disposed between the prism and the optical disc for
permitting the laser beam to focus on the disc via the prism.
14. An optical pickup device substantially as hereinbefore described with
reference to Figure 2 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019960013002A KR0174473B1 (en) | 1996-04-26 | 1996-04-26 | An optical pickup device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9708506D0 GB9708506D0 (en) | 1997-06-18 |
| GB2312547A true GB2312547A (en) | 1997-10-29 |
Family
ID=19456770
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9708506A Withdrawn GB2312547A (en) | 1996-04-26 | 1997-04-25 | Optical pickup device mounted on silicon substrate |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPH1055568A (en) |
| KR (1) | KR0174473B1 (en) |
| GB (1) | GB2312547A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3696496B2 (en) * | 2000-10-10 | 2005-09-21 | アルプス電気株式会社 | Composite optical component and composite optical unit using the same |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0258450A1 (en) * | 1986-02-24 | 1988-03-09 | Sony Corporation | Device for detecting focus |
| EP0278406A2 (en) * | 1987-02-06 | 1988-08-17 | Sony Corporation | Optical pickup head |
| EP0468612A2 (en) * | 1990-07-25 | 1992-01-29 | Pioneer Electronic Corporation | Optical pickup |
| EP0545905A2 (en) * | 1987-07-30 | 1993-06-09 | Sony Corporation | Optical pickup element |
-
1996
- 1996-04-26 KR KR1019960013002A patent/KR0174473B1/en not_active IP Right Cessation
-
1997
- 1997-04-25 GB GB9708506A patent/GB2312547A/en not_active Withdrawn
- 1997-04-25 JP JP9109804A patent/JPH1055568A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0258450A1 (en) * | 1986-02-24 | 1988-03-09 | Sony Corporation | Device for detecting focus |
| EP0278406A2 (en) * | 1987-02-06 | 1988-08-17 | Sony Corporation | Optical pickup head |
| EP0545905A2 (en) * | 1987-07-30 | 1993-06-09 | Sony Corporation | Optical pickup element |
| EP0468612A2 (en) * | 1990-07-25 | 1992-01-29 | Pioneer Electronic Corporation | Optical pickup |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9708506D0 (en) | 1997-06-18 |
| JPH1055568A (en) | 1998-02-24 |
| KR0174473B1 (en) | 1999-04-15 |
| KR970071552A (en) | 1997-11-07 |
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