GB2109583A - Optical head devices for generating and controlling a light beam - Google Patents
Optical head devices for generating and controlling a light beam Download PDFInfo
- Publication number
- GB2109583A GB2109583A GB08231383A GB8231383A GB2109583A GB 2109583 A GB2109583 A GB 2109583A GB 08231383 A GB08231383 A GB 08231383A GB 8231383 A GB8231383 A GB 8231383A GB 2109583 A GB2109583 A GB 2109583A
- Authority
- GB
- United Kingdom
- Prior art keywords
- supporting member
- optical head
- light beam
- hologram
- head device
- 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.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 70
- 239000004065 semiconductor Substances 0.000 claims abstract description 28
- 239000010409 thin film Substances 0.000 description 5
- 230000035939 shock Effects 0.000 description 2
- 108010010803 Gelatin Proteins 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- SOCTUWSJJQCPFX-UHFFFAOYSA-N dichromate(2-) Chemical compound [O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O SOCTUWSJJQCPFX-UHFFFAOYSA-N 0.000 description 1
- 229920000159 gelatin Polymers 0.000 description 1
- 239000008273 gelatin Substances 0.000 description 1
- 235000019322 gelatine Nutrition 0.000 description 1
- 235000011852 gelatine desserts Nutrition 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
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
- G11B7/1353—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
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
- G11B7/1356—Double or multiple prisms, i.e. having two or more prisms in cooperation
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/16—Beam splitting or combining systems used as aids for focusing
-
- 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
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
-
- 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
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0925—Electromechanical actuators for lens positioning
- G11B7/093—Electromechanical actuators for lens positioning for focusing and tracking
-
- 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
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0925—Electromechanical actuators for lens positioning
- G11B7/0937—Piezoelectric actuators
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- General Physics & Mathematics (AREA)
- Optical Head (AREA)
Abstract
An optical head device 10 for generating and controlling a light beam comprises a cylindrical supporting member 11, a semiconductor laser 12 contained in the supporting member 11 for generating a laser light beam and a hologram 16 operative to convert a spherical light wave diverging from one point into another spherical light wave converging to another point, the hologram 16 being attached to the cylindrical supporting member 11 so that the laser light beam generated by the semiconductor laser 12 passes through the hologram 16 in the direction along the axis of the cylindrical supporting member 11. A beam splitter 13 and a photo-sensor 18 may also be contained in the cylindrical supporting member 11 at positions between the semiconductor laser 12 and the hologram 16. <IMAGE>
Description
SPECIFICATION
Optical head devices for generating and controlling a light beam
This invention relates to optical head devices for generating a controlling a light beam.
Embodiments of the invention can be used in an apparatus for optically reproducing information recorded on a record medium, such as, an optical disc player.
As an optical head device for use in an apparatus for reproducing information recorded on an optical record disc, it has been proposed to employ a compact optical pick-up device for guiding a light beam onto the optical record disc and receiving the light beam reflected from, or transmitted through the optical record disc, which optical pick-up device is generally referred to as being of the pencil type. In such a previously proposed optical pick-up device of the pencil type, a semiconductor laser for emitting a laser light beam, a polarized beam splitter, a collimator lens, a quarter-wave plate, an object lens and a photosensor are contained in a common cylindrical supporting member which is disposed so that the object lens faces the optical record disc.
However, since both the collimator lens and the object lens are contained in the common cylindrical supporting member, the cylindrical supporting member is relatively long in the axial direction and is also relatively heavy. In practice, it has been necessary for the collimator lens and the object lens are each to have a lengh of more than 4mm and a weight of more than 400mg in order adequately to perform their respective optical functions and, therefore, it has been almost impossible for the device, as a whole, to have a
length of less than 35mm and a weight of less than 5g.
Consequently, it has been very difficult to achieve correct focus servo-control and tracking servo-control for the laser light beam directed onto the optical record disc from the object lens,
by mounting the previously proposed optical pick
up device of the pencil type on a control device
which moves the optical pick-up device in two
perpendicular directions. Therefore, in the
previously proposed optical pick-up device of the
pencil type, the object lens is moved individually,
that is, relative to the common cylindrical
supporting member, in the direction of the axis
thereof, for performing the focus servo-control,
and the device as a whole is moved in the
direction perpendicular to the axial direction of
the common cylindrical member for performing
the tracking servo-control.This arrangement is
disadvantageous because the servo-control
frequency band is not sufficiently broad, and the
resistance to shocks is poor.
Although it is theoretically possible to use an
object lens for directly converging the laser light
beam emitted from the semiconductor laser into a
very small point, thereby eliminating the need for
the collimator lens, the object lens in such a case
would be too long and heavy. Moreover, such an object lens would be formed by a plurality of lenses in the common cylindrical supporting member and, therefore, production of the optical pick-up device would be difficult.
According to the present invention there is provided an optical head device for generating and controlling a light beam, the device comprising:
a generally cylindrical supporting member;
a semiconductor laser contained in said supporting member for emitting a laser light beam; and
a hologram attached to said supporting member in such a manner that said laser light beam emitted by said semiconductor laser passes through said hologram in a direction along the axis of said cylindrical supporting member, said hologram being operative to convert a spherical light wave diverging from a point at said laser into another spherical light wave converging to another point outside said cylindrical supporting member.
The invention will now be described by way of example with reference to the accompanying drawings, throughout which like parts are referred to by like references, and in which:
Figure 1 is a schematic sectional view showing an example of optical pick-up device of the pencil type according to the prior art;
Figure 2 is a schematic sectional view showing one embodiment of optical head device according to the invention;
Figures 3 to 5 are diagrammatic views to which reference will be made in explaining how a hologram is produced for use in an optical head device according to the invention;
Figure 6 is a plan view showing a controlled mounting movably supporting the optical head device of Figure 2;
Figure 7 is a sectional view taken along the line VIl-VIl in Figure 6;;
Figure 8 is a perspective viewe of a part of the controlled mounting shown in Figures 6 and 7;
Figure 9 is a sectional view similar to that of
Figure 7, but showing another example of the controlled mounting for movably supporting the optical head device of Figure 2;
Figure 10 is a schematic sectional view showing another embodiment of optical head device according to the invention; and
Figure 11 is a plan view of a controlled mounting for movably supporting the optical head device of Figure 10.
To facilitate understanding of the embodiments of the invention, an example of an optical pick-up device according to the prior art will first be explained with reference to Figure 1. This optical pick-up device is of the pencil type and comprises a cylindrical supporting member 1 in which there are suitably disposed a semi-conductor laser 2, a polarized beam splitter 3, a collimator lens 4, a quarter-wave plate 5, an object lens 6 and a photosensor 8. In order to detect errors in the focusing of a laser light beam generated by the semiconductor laser 2 and impinged on an optical record disc 9 through the object lens 6, a prism 7 is provided integrally with the polarized beam splitter 3 at a surface of the latter from which the laser light beam emerges after being reflected from the record disc 9.The prism 7 is disposed so that a ridge line thereof lies in the direction perpendicular to the axis of the laser light beam passing therethrough, and the photosensor 8 is divided into four sections along spaced apart lines of separation which extend parallel to each other and to the ridge line of the prism 7.
This previously proposed optical pick-up device of the pencil type is undesirably long in the direction of the axis of the cylindrical supporting member 1, and also is undesirably heavy, because both the collimator lens 4 and the object lens 6 are contained in the common cylindrical supporting member 1.
A first preferred embodiment of optical head device 10 according to the invention will now be explained with reference to Figure 2. A cylindrical supporting member 11 contains a semiconductor laser 12, a polarized beam splitter 13, a quarterwave plate 15, a hologram 16 and a photo-sensor 18. In this embodiment, a prism 17 is also shown to be provided on a surface of the polarized beam splitter 13 as an integral part thereof, and the photo-sensor 18 is divided into four sections in the same manner as the photo-sensor 8 mentioned above.
The hologram 16 used in optical head device 10 is operative to convert a spherical light wave diverging from one point into another spherical light wave converging to another point, that is, the hologram 16 acts as a lens for focusing a light beam. By way of example, and as shown in Figure 3, the hologram 16 can be obtained by placing an auxiliary hologram 22 and a thin film 16a of dichromate gelatin which is to become the hologram 16, in a light path passing through an object lens 21. A converging spherical light wave
having a numerical aperture sin 6i is brought by the auxiliary hologram 22 to interfere with a diverging spherical light wave of numerical aperture sin 62 brought by the object lens 21 onto thin film 16a.In this way the thin film 16a is turned into the hologram 16 which can act as a
lens for converting a spherical light wave
diverging from a point F1 with the numerical
aperture sin 61 into a spherical light wave
converging to a point F2 with the numerical
aperture sin 62. Moreover, as shown in Figure 4,
the auxiliary hologram 22 can be obtained by
placing a thin film 22a in a light path passing
through an object lens 23, and causing a
converging spherical light wave of numerical
aperture sin 61 to be brought by the object lens 23
into interference with a plane light wave on the thin film 22a.
Since the hologram 16 can act generally as a
lens for converging a spherical light wave
diverging from one point into another spherical
light wave converging to another point, it is
possible to use the hologram 16 to focus the laser light beam diverging from the semiconductor laser 12 onto the record disc 9 as shown in Figure 2 and to read the information recorded thereon without using the collimator and the object lenses of the prior art.
The optical head device 10 according to the invention is substantially miniaturized in size and very much reduced in weight. For example, when the radius of an equivalent lens formed by the hologram 16 and of numerical aperture sin 62 are 2mm and 0.5, respectively, the hologram 16 can be placed at a distance of 3.46mm from the recorded surface of the record disc 9. In that case, if the laser light beam focused by the hologram 1 6 is directed through the body of the record disc 9 to the recorded surface of the record disc 9 for reading the information recorded thereon, and if the thickness of the body of the record disc 9 is 1.2mm., the distance between the hologram 16 and the record disc 9 is 2.26mm.Moreover, if the above mentioned numerical aperture sin 6i is arranged to be 0.15, the distance between the semiconductor laser 12 and the hologram 16 is only 13.1 8mum, from which is follows that the optical head device 10 is, as a whole, substantially miniaturized, and it may, for example, be less than 15mm. Moreover, in a case where the hologram 16 is formed with an area of 9mm2 and a thickness of 1.2mm, its weight is about 270mg.Since the polarized beam splitter 13 can be formed with its body measuring 5mm3 to weigh approximately 340mg, the semiconductor laser 12 weighs approximately 500mg and the photo-sensor 18 weighs approximately 400mg, and it is possible for the cylindrical supporting member 11 to weigh less than 1 g by being made, for example, of aluminium, the optical head device 10, as a whole, can be made to weigh less than 39.
Incidentally, although it is possible to obtain only a circular aperture when using an ordinary lens made of glass, the aperture of the equivalent lens formed by the hologram 16 can be made to have various shapes, for example, elliptical, square, rectangular or other desirable shapes, by providing a mask 24 of the desired shape, as shown in Figure 5. In the case of the elliptical or rectangular aperture, the amount of laser light beam passing therethrough is increased when the laser light beam is emitted with anisotropy from the semiconductor laser 12, so that the utlization efficiency of the laser light beam is improved. By
reason of such increase in utilization efficiency, the emitting power of the semiconductor laser 12 can be reduced so that the useful life of the semiconductor laser 12 is extended.
Since the optical head device 10 is substantially miniaturized and greatly reduced in weight, it is possible to achieve the focus servocontrol and the tracking servo-control of the laser
light beam directed onto the record disc 9 by a
controlled mounting of the optical head device 10 which moves the latter, as a unit, in two
perpendicular directions, while ensuring that the frequency band of the servo-control will be
sufficiently broad and that there will be superior resistance to shocks. One example of a controlled mounting for moving the optical head device 10 in two perpendicular directions is shown in
Figures 6 and 7. In this example, a bobbin 31 having coaxial inner and outer cylindrical portions 31 a and 31 b is provided for mounting of the optical head device 10 in its inner cylindrical portion 31 a.A first moving coil 32 for the focus servo-control and a second moving coil 33 for the tracking servo-control are fixed on the outside of the bobbin 31, as also shown in Figure 8. A pair of magnetic yokes 34A and 34B, to which a pair of magnets 35A and 35B, respectively, are attached, are disposed opposite to each other with the bobbin 31 therebetween. The top end of the inner cylindrical portion 31 a of the bobbin 31 and the top end of cylindrical supporting member 11 of the optical head device 10 are movably supported or suspended through a pair of resiliently flexible elements or dampers 36A and 36B from the upper ends of the magnetic yokes 34A and 34B.
The bottom end of the inner cylindrical portion 31 a of the bobbin 31 is also movably supported through a resiliently flexible element or damper 37 from the bottom ends of the magnetic yokes 34A and 34B so that the optical head device 10 can move with the bobbin 31 both in the direction of the axis of the bobbin 31, that is, in the up-anddown direction, and in the direction at right angles to such axis, as indicated by the doubleheaded arrow 38 in Figure 6.
As mentioned above, the length of the optical head device 10 can be less than 15mm and, therefore, it is possible to form the bobbin 31 to have an outer diameter of about 22mm. In such a case, for example, the magnetic yokes 34A and 34B can be dimensioned, in the direction from top to bottom, to be about 25mm and, in the lateral direction, to be about 36mm. Further, as also earlier noted, the weight of the optical head device 10 can be less than 3g and, therefore, it is possible to obtain a focus servo-control frequency band extended to, for example, 1.5 kHz, and a tracking servo-control frequency band extended, for example, to 3 kHz. These servo-control frequency bands are sufficiently broad for the respective servo-controls.
Figure 9 shows another example of a controlled mounting for supporting the optical head device 10 to move in two perpendicular directions. The optical head device 10 is shown to be inserted into the magnetic assembly comprising the magnetic yokes 34A and 34B and the magnets 35A and 35B in the embodiment shown in Figures 6 and 7. However, in the example of Figure 9, the cylindrical supporting member 11 of the optical head device 10 is elongated or extended downward, as at 11 a, and a bobbin 41 is formed integrally with such elongated portion 11 a of the cylindrical supporting member 11. A moving coil 42 for the focus servo control is wound on the bobbin 41 and a magnetic assembly comprising magnetic yokes 44 and 45 and a magnetic 46 therebetween is provided around the elongated portion 11 a of the cylindrical supporting member
11.A ring-shaped member 47 extends upwardly from the magnetic yoke 44 at the top of the latter, and a pair of stationary coils 43A and 43B for the tracking servo-control are attached to the inner surface of the ring-shaped member 47 at diametrically opposed locations on the latter.
Further, a pair of magnets 49A and 49B are attached through holders 48A and 48B to the outside of the supporting member 11 of the optical head device 10 at positions facing the stationary coils 43A and 43B, respectively. The cylindrical supporting member 11 is movably supported through a damper 50 by the ringshaped member 47 and through a damper 51 by another ring-shaped member 52 connected to the magnetic yoke 45 at the bottom end of the latter.
Figure 10 shows another embodiment of an optical head device 1 OA according to the invention, and in which the polarized beam splitter 13 and the quarter-wave plate 15 of
Figure 2 are not used and a semiconductor laser 12A is operative to function as a photo-detector as well as the source of the laser light beam. The hologram 16 is operative so as very positively to return the reflected laser light beam from the optical record disc 9 to the semiconductor 12A, and the embodiment of Figure 10 makes the most of this characteristic of the hologram 1 6. With this embodiment, it is not necessary to provide any projecting portion on the outside of the cylindrical supporting member 11 A, as distinguished from the embodiment of Figure 2 in which the member 11 has a lateral projecting portion 11' to house the photo-sensor 18.
Therefore, the cylindrical supporting member 11A can be made symmetrical in all directions about its longitudinal axis to permit achievement of an additional servocontrnl for time base correction of the reproduced signal obtained from the information read by the laser light beam in addition to the focus and tracking servo-controls.
For achieving the foregoing, there is provided a three-dimensional controlled mounting which can move the cylindrical supporting member 11A mounted thereon in three different directions perpendicular to one another, for example, as shown in Figure 11.
More particularly, the optical head device 1 0A of Figure 10 is shown in Figure 11 to be mounted on a magnetic assembly which is substantially the same as that described above with reference to
Figure 9. Thus, the magnetic assembly of Figure 11 is shown to include a ring-shaped member 47 and stationary coils 43A and 43B for the tracking servo-control attached to the inner surface of the ring-shaped member 47 at locations which are diametrically opposite to each other in a first direction. However, in Figure 11, another pair of stationary coils 53A and 53B for the time base correction servo-control are also attached to the inner surface of the ring-shaped member 47 so as to be diametrically opposite to each other in a second direction perpendicular to the first direction.A rectangular holder 48 is mounted on the outside of the optical head device 1 OA, and magnets 49A and 49B are attached to the surface of the rectangular holder 48 which are opposite to the stationary coils 43A and 43B, respectively.
Another pair of magnets 59A and 59B are attached to the surface of the rectangular holder 48 which are opposite to the stationary coils 53A and 53B, respectively. Thus, the optical head device 1 0A can be moved in the directions perpendicular to one another indicated by the double-headed arrows 38 and 58 in Figure 11 for correcting tracking errors and for correcting time base errors, respectively, by the selective energizing of the coils 43A and 438 and the coils 53A and 53B, respectively. The controlled mounting for the optical head device 1 OA further includes an arrangement (not shown) for effecting movement of the supporting member 11 A in the direction of its longitudinal axis so as to correct focusing errors, for example, as formed by the coil 42 and the magnet 45 of Figure 9.Therefore, the optical head device 1 OA can be moved in all three directions perpendicular to each other for effecting tracking, time base and focusing servocontrol.
In the optical head device 1 OA, a piezoelectric element 61 is provided between the bottom of the cylindrical supporting member 11 A and the semiconductor laser 12A, as shown in Figure 10.
A voltage for wobbling operation is suitably supplied to the piezoelectric element 61 for vibrating it and thereby wobbling the semiconductor laser 12A in the direction along the axis of the laser light beam emitted by the laser 12A so that errors in the focus servo-control can be detected in a known manner.
Alternatively, in place of the piezoelectric element 61, a rear monitor photodetector 19 may be provided for the semiconductor laser 12A to detect errors in the focus servo-control. Moreover,
another piezoelectric element 62 may be provided
between the top end of the cylindrical supporting
member 11 A and the hologram 16, as shown in
Figure 10. A voltage is suitably supplied to the
piezoelectric element 62 for vibrating it and
therefore wobbling the hologram 16 in the
direction perpendicular to the axis of the laser
light beam emitted by the semiconductor laser
12A. Such wobbling of the hologram 16 is
employed, in a known manner, in order to detect
errors in the tracking servo-control. More
particularly, errors in the tracking servo-control
may be detected by a photo-sensor (not shown)
provided for receiving the laser light beam after it
has passed the wobbled hologram 16 and been
reflected at the optical record disc 9.
Claims (13)
1. An optical head device for generating and
controlling a light beam, the device comprising:
a generally cylindrical supporting member;
a semiconductor laser contained in said
supporting member for emitting a laser light
beam; and
a hologram attached to said supporting member in such a manner that said laser light beam emitted by said semiconductor laser passes through said hologram in a direction along the axis of said cylindrical supporting member, said hologram being operative to convert a spherical light wave diverging from a point at said laser into another spherical light wave converging to another point outside said cylindrical supporting member.
2. An optical head device according to claim 1 further comprising a beam splitter means contained in said supporting member at a position between said semiconductor laser and said hologram, and a photo-sensor attached to said supporting member to receive a laser light beam split by said beam splitter.
3. An optical head device according to claim 2 further comprising mounting means for holding said cylindrical supporting member, and driving means for electromagnetically moving said mounting means in at least two different directions.
4. An optical head device according to claim 3 wherein said driving means electromagnetically moves said mounting means in both a first direction along said axis of said cylindrical supporting member and a second direction perpendicular to said first direction.
5. An optical head device according to claim 1 wherein said semiconductor laser is attached through a first piezoelectric element to said cylindrical supporting member and said hologram is attached through a second piezoelectric element to said cylindrical supporting member.
6. An optical head device according to claim 5 wherein said laser light beam emerges from said supporting member through said hologram and is reflected at the outside of said supporting member so as to re-enter said supporting member through said halogram, and said semiconductor laser also receives said laser light beam which reenters the supporting member.
7. An optical head device according to claim 1 wherein said laser light beam emerges from said supporting member through said hologram and is reflected at the outside of said supporting member so as to re-enter said supporting member through said hologram and be directed by said hologram against said semiconductor laser.
8. An optical head device according to claim 7 further comprising mounting means for holding said cylindrical supporting member, and driving means for electromagnetically moving said mounting means in the direction of said axis of the cylindrical supporting member for focus servo-control and in orthogonally related directions which are perpendicular to said axis for tracking and time base servo-controls.
9. An optical head device for generating and controlling a light beam, the device being substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.
10. An optical head device for generating and controlling a light beam, the device being substantially as hereinbefore described with reference to Figures 2 and 6 to 8 of the accompanying drawings.
11. An optical head device for generating and controlling a light beam, the device being substantially as hereinbefore described with reference to Figures 2 and 9 of the accompanying drawings.
12. An optical head device for generating and controlling a light beam the device being substantially as hereinbefore described with reference to Figure 10 of the accompanying drawings.
13. An optical head device for generating and controlling a light beam, the device being substantially as hereinbefore described with reference to Figures 10 and 11 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56176749A JPS5880139A (en) | 1981-11-04 | 1981-11-04 | Optical head |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2109583A true GB2109583A (en) | 1983-06-02 |
| GB2109583B GB2109583B (en) | 1985-07-17 |
Family
ID=16019131
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08231383A Expired GB2109583B (en) | 1981-11-04 | 1982-11-03 | Optical head devices for generating and controlling a light beam |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS5880139A (en) |
| KR (1) | KR880002635B1 (en) |
| AT (1) | AT376510B (en) |
| AU (1) | AU556305B2 (en) |
| CA (1) | CA1177165A (en) |
| DE (1) | DE3240734C2 (en) |
| FR (1) | FR2519458B1 (en) |
| GB (1) | GB2109583B (en) |
| NL (1) | NL8204248A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0146177A1 (en) * | 1983-12-07 | 1985-06-26 | Koninklijke Philips Electronics N.V. | Single collimator lens having one aspherical surface |
| EP0539217A2 (en) * | 1991-10-25 | 1993-04-28 | Tandy Corporation | Holographic elements for an optical recording system |
| EP0559435A1 (en) * | 1992-03-05 | 1993-09-08 | International Business Machines Corporation | Improvements in holographic techniques |
| US8149793B2 (en) | 2004-04-15 | 2012-04-03 | Koninklijke Philips Electronics N.V. | Allocation of access slots to mobile stations in order to count the number of stations interested in a MBMS (multimedia broadcast/multicast service) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1258906A (en) * | 1985-04-22 | 1989-08-29 | Hiroshi Oinoue | Semiconductor laser apparatus for optical head |
| JPS61269235A (en) * | 1985-05-24 | 1986-11-28 | Omron Tateisi Electronics Co | Optical information processing device |
| JPS61269233A (en) * | 1985-05-24 | 1986-11-28 | Omron Tateisi Electronics Co | Optical information processing device |
| JPH0687099B2 (en) * | 1986-10-08 | 1994-11-02 | 富士通株式会社 | Laser optical scanning device |
| EP0767953A2 (en) * | 1995-03-29 | 1997-04-16 | Koninklijke Philips Electronics N.V. | Optical unit comprising a radiation source, a detector and a grating, and scanning device including the optical unit |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4003059A (en) * | 1974-02-07 | 1977-01-11 | Canon Kabushiki Kaisha | Optical recorder having focus controlling means |
| NL176315C (en) * | 1976-05-12 | 1985-03-18 | Philips Nv | OPTICAL SCANNER. |
| NL7608561A (en) * | 1976-08-02 | 1978-02-06 | Philips Nv | OPTICAL READING UNIT FOR SCANNING A RECORD BEARING WITH A RADIATION-REFLECTING INFORMATION STRUCTURE. |
| CA1091966A (en) * | 1976-10-15 | 1980-12-23 | Chiaki Kojima | Apparatus for reading signals recorded on a record carrier |
| US4245882A (en) * | 1977-11-04 | 1981-01-20 | Environmental Research Institute Of Michigan | Doubly modulated on-axis thick hologram optical element |
| NL7713711A (en) * | 1977-12-12 | 1979-06-14 | Philips Nv | OPTICAL READING UNIT FOR READING A MOVING DATA CARRIER, IN PARTICULAR FOR READING A VIDEO RECORD. |
| JPS54109801A (en) * | 1978-02-17 | 1979-08-28 | Toshiba Corp | Optical reader |
| JPS5573934A (en) * | 1978-11-20 | 1980-06-04 | Mansei Kogyo Kk | Reader for optical information |
| JPS55163566A (en) * | 1979-06-05 | 1980-12-19 | Sony Corp | Hologram lens and its production and optical system signal using this hologram lens |
| JPS5647933A (en) * | 1979-09-25 | 1981-04-30 | Sony Corp | Optical signal head |
| JPS5680836A (en) * | 1979-12-07 | 1981-07-02 | Seiko Instr & Electronics Ltd | Optical information reader |
-
1981
- 1981-11-04 JP JP56176749A patent/JPS5880139A/en active Pending
-
1982
- 1982-11-01 AU AU90071/82A patent/AU556305B2/en not_active Expired
- 1982-11-02 NL NL8204248A patent/NL8204248A/en active Search and Examination
- 1982-11-02 CA CA000414665A patent/CA1177165A/en not_active Expired
- 1982-11-03 GB GB08231383A patent/GB2109583B/en not_active Expired
- 1982-11-04 FR FR828218524A patent/FR2519458B1/en not_active Expired - Lifetime
- 1982-11-04 KR KR8204975A patent/KR880002635B1/en active
- 1982-11-04 DE DE3240734A patent/DE3240734C2/en not_active Expired - Lifetime
- 1982-11-04 AT AT0403082A patent/AT376510B/en not_active IP Right Cessation
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0146177A1 (en) * | 1983-12-07 | 1985-06-26 | Koninklijke Philips Electronics N.V. | Single collimator lens having one aspherical surface |
| EP0539217A2 (en) * | 1991-10-25 | 1993-04-28 | Tandy Corporation | Holographic elements for an optical recording system |
| EP0539217A3 (en) * | 1991-10-25 | 1993-09-29 | Tandy Corporation | Holographic elements for an optical recording system |
| EP0559435A1 (en) * | 1992-03-05 | 1993-09-08 | International Business Machines Corporation | Improvements in holographic techniques |
| US5272690A (en) * | 1992-03-05 | 1993-12-21 | International Business Machines Corporation | Hologram element system |
| US8149793B2 (en) | 2004-04-15 | 2012-04-03 | Koninklijke Philips Electronics N.V. | Allocation of access slots to mobile stations in order to count the number of stations interested in a MBMS (multimedia broadcast/multicast service) |
Also Published As
| Publication number | Publication date |
|---|---|
| ATA403082A (en) | 1984-04-15 |
| AU556305B2 (en) | 1986-10-30 |
| AT376510B (en) | 1984-11-26 |
| FR2519458A1 (en) | 1983-07-08 |
| DE3240734A1 (en) | 1983-05-19 |
| CA1177165A (en) | 1984-10-30 |
| KR840002561A (en) | 1984-07-02 |
| NL8204248A (en) | 1983-06-01 |
| GB2109583B (en) | 1985-07-17 |
| JPS5880139A (en) | 1983-05-14 |
| KR880002635B1 (en) | 1988-12-07 |
| DE3240734C2 (en) | 1995-11-30 |
| FR2519458B1 (en) | 1991-07-19 |
| AU9007182A (en) | 1983-05-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PE20 | Patent expired after termination of 20 years |
Effective date: 20021102 |