CN100466075C - Optical read/write head - Google Patents
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- CN100466075C CN100466075C CNB200610058292XA CN200610058292A CN100466075C CN 100466075 C CN100466075 C CN 100466075C CN B200610058292X A CNB200610058292X A CN B200610058292XA CN 200610058292 A CN200610058292 A CN 200610058292A CN 100466075 C CN100466075 C CN 100466075C
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Abstract
A optical read/write head is prepared as using light source to emit a light beam and collimating light beam by collimation lens, separating light beam by polarization spectroscope according to polarized direction, focusing light beam to be on a focusing point by focusing lens, setting optical compensation element between said focusing point and polarization spectroscope, setting spherical image error reviser between focusing point and focusing lens and using optical detector to detect light beam transmitted from polarization spectroscope.
Description
Technical field
The present invention relates to a kind of optical read/write head, particularly relate to a kind of optical read/write head that can be applicable to have several record layers and dissimilar optical data storage media.
Background technology
Along with the arriving of information and multimedia era, the consumer increases sharp for the demand of Storage Media capacity.Wherein, because optical data storage media can store a large amount of data, and the characteristic that has portability and can preserve data for a long time, make that utilizing optical data storage media to come the access data has been the mode of quite popularizing.
In the face of more and more huge audio-visual information amount, improve the volume of information of optical data storage media, be the target that the dealer pursues always.Store additional information on the optical data storage media of equal volume, mode commonly used has two kinds: first method is to dwindle laser spot (Laser Beam Spot-size) so that shorten gauge (Track Pitch); Second method then is the number of plies that increases optical data storage media, writes (Multilayer Recording) effect to reach multilayer.These methods have caused optical data storage media more to develop, and are used for reading and writing the optical read/write head (Optical Pick-UpHead) of optical data storage media, also need change in response to these development.
Because luminous point size is proportional with optical source wavelength, and with the numerical aperture of condenser lens (Numerical Aperture NA) is inverse ratio.Therefore, the wavelength that dwindles laser spot and be exactly optical read/write head institute emission laser beam need shorten, and the numerical aperture of condenser lens need become big.(Compact Disc CD), need be that the laser beam of 780nm is read and write with wavelength, and the numerical aperture of condenser lens be 0.45 to laser disc; Concerning digital video disc (DVD), laser beam is that wavelength is the red laser of 650nm, and the numerical aperture of condenser lens is 0.65; To Blu-ray Disc (Blue-rayDisc, BD), laser beam is that wavelength is the blue laser of 405nm, the numerical aperture of condenser lens is 0.85.By first method, the capacity of optical data storage media is developed to digital video disc family more than the 4.7GB from the laser disc family of 650MB, even is developed to the more Blu-ray Disc of high power capacity.
Just as the digital video disc of present single-surface double-layer (DVD-9), two-sided individual layer (DVD-10) and the two-sided bilayer (DVD-18) that can see on the market, its capacity is respectively 8.5GB, 9.4GB, 17GB to second method.Though the capacity of optical data storage media is developing and is increasing always, however the less laser disc of capacity be not eliminated, but also used in a large number.In the face of the optical data storage media of these specifications, the manufacturer of optical read/write head also needs to consider the compatibility (Compatibility) to optical data storage media when producing.
See also shown in Figure 1, the optical read/write head 1 of known techniques is to comprise a light source 11, collimation lens (Collimator) 12, a polarization spectroscope (Polarizing Beam Splitter, PBS) 13, one quarter-wave plate (Quarter-wave Plate), 14, one condenser lens (Focusing Lens), 15, one photodetector (Photo Detector), 16 and one optical sheet (0ptical Plate) 17.Light source 11 is emission one light beams, becomes directional light behind collimation lens 12 collimations.In polarization spectroscope 13, the part of light beam is reflected, and becomes linearly polarized light (Linearly Polarized Light).Linearly polarized light then becomes circularly polarized light (Circularly Polarized Light) through quarter-wave plate 14.The optical sheet 17 that has fixed thickness again via condenser lens 15 focusing and process, thereby to revise the recording layer that spherical aberration focuses to optical data storage media D exactly.By the reflective layer reflects of optical data storage media D, wherein, the polarised direction of the circularly polarized light of reflection is opposite with the polarised direction of the circularly polarized light of incident then.After passing through quarter-wave plate 14 again, become linearly polarized light, the polarised direction of the polarised direction of this linearly polarized light and the linearly polarized light of incident is a quadrature.After penetrating polarization spectroscope 13 fully again, detected by photodetector 16.
Generally speaking, optical read/write head 1 is to utilize optical sheet 17 to revise spherical aberration, and is applied to the different recording layer in a kind of optical data storage media.Yet because the thickness of optical sheet 17 is for fixing, so optical read/write head 1 can only be read and write two layers of recording layer with specific distance, when the spacing that has pluratity of recording layers more or a recording layer as optical data storage media D changed, optical read/write head 1 promptly can't be used.In addition, because the thickness of quarter-wave plate 14 is for fixing, so can only allow the Beam Transformation of a specific wavelength to become linearly polarized light or circularly polarized light, received by photodetector 16 to penetrate polarization spectroscope 13 fully, when optical read/write head 1 is wanted can be applied to laser disc (CD), digital video disc (DVD) or Blu-ray Disc (BD simultaneously, HD-DVD) time, the light beam that just needs two or more specific wavelengths, so optical read/write head 1 also can't be applied to dissimilar optical data storage medias, and has reduced compatibility.
From the above, how to provide a kind of optical read/write head, in the face of by the recording layer of different spacing, or during by spherical aberration that different optical data storage media produced, all can accurately focus on the recording layer that to read and write; And can be when facing the dissimilar required light beams of different wavelengths of optical data storage media, all can make Beam Transformation become linearly polarized light or circularly polarized light, being received by photodetector to penetrate the polarization spectroscope fully, and then increase the compatibility and the function of optical read/write head, is an important topic in fact.
This shows that above-mentioned existing optical read/write head obviously still has inconvenience and defective, and demands urgently further being improved in structure and use.In order to solve the problem that optical read/write head exists, relevant manufacturer there's no one who doesn't or isn't seeks solution painstakingly, but do not see always that for a long time suitable design finished by development, and common product does not have appropriate structure to address the above problem, this obviously is the problem that the anxious desire of relevant dealer solves.Therefore how to found a kind of novel optical read/write head, just becoming the current industry utmost point needs improved target.
Because the defective that above-mentioned existing optical read/write head exists, the inventor is based on being engaged in this type of product design manufacturing abundant for many years practical experience and professional knowledge, and the utilization of cooperation scientific principle, actively studied innovation, in the hope of founding a kind of novel optical read/write head, can improve general existing optical read/write head, make it have more practicality.Through constantly research, design, and, create the present invention who has practical value finally through after studying sample and improvement repeatedly.
Summary of the invention
Fundamental purpose of the present invention is, overcome the defective that existing optical read/write head exists, and provide a kind of novel optical read/write head, technical matters to be solved is to make it that a kind of optical read/write head that can increase for the compatibility and the function of optical data storage media is provided, thereby is suitable for practicality more.
The object of the invention to solve the technical problems realizes by the following technical solutions.According to a kind of optical read/write head that the present invention proposes, it comprises a light source, launches a light beam; One collimation lens collimate this light beam; One polarization spectroscope separates this light beam according to polarised direction; At least one condenser lens focuses on this light beam to one focus point; One optical compensatory element, between this focus point and this polarization spectroscope, this optical compensatory element is to comprise liquid crystal; One spherical aberration correction device between this focus point and this condenser lens, and comprises two clinohedrals, adjusts the thickness of this spherical aberration correction device by the mutual displacement of these two clinohedrals; And a photodetector, detect this light beam that transmits from this polarization spectroscope.
The object of the invention to solve the technical problems also can be applied to the following technical measures to achieve further.
Aforesaid optical read/write head, wherein said light source are a blue laser diode or a red laser diode.
Aforesaid optical read/write head, wherein said optical compensatory element comprises two glass substrates, and liquid crystal places between this glass substrate.
Aforesaid optical read/write head, wherein said optical compensatory element provides the phase pushing figure of these light beam one 90 degree, when this light beam is a linearly polarized light, then this Beam Transformation is become a circularly polarized light, maybe when this light beam is a circularly polarized light, then with this Beam Transformation being aligned polarized light.
Aforesaid optical read/write head, the material of wherein said spherical aberration correction device are polycarbonate, plastic cement or glass.
Aforesaid optical read/write head, wherein said clinohedral has an inclined-plane respectively, and these clinohedrals are respectively along this inclined-plane relative displacement.
Aforesaid optical read/write head, wherein said clinohedral are two sphenoids or are two triangle bodies.
Aforesaid optical read/write head, comprising: a displacement micro-actuator, in order to adjust the mutual displacement of these clinohedrals, to change the thickness of this spherical aberration correction device.
Aforesaid optical read/write head, wherein said focus point is positioned at an optical data storage media, this optical data storage media comprises one first recording layer, a wall and one second recording layer, and this wall is between this first recording layer and this second recording layer, and the thickness of this wall is t
s, refraction coefficient is n (s), and this light beam is t by thickness, and refraction coefficient is this spherical aberration correction device of n, then t, t
s, n (s), n meet following equation:
t＝t
s*n(s)/n
Aforesaid optical read/write head, wherein said light beam is passed through in regular turn by this light source: this collimation lens, this polarization spectroscope, this optical compensatory element, this condenser lens, this spherical aberration correction device, this optical data storage media, this spherical aberration correction device, this condenser lens, this optical compensatory element, this polarization spectroscope and this photodetector.
Via as can be known above-mentioned, the invention relates to a kind of optical read/write head, comprise a light source, collimation lens, a polarization spectroscope, at least one condenser lens, an optical compensatory element, a spherical aberration correction device and a photodetector.Light emitted one light beam; The collimation lens collimated light beam; The polarization spectroscope is according to the polarised direction separating light beam; Condenser lens focused beam to a focus point; Optical compensatory element is between focus point and polarization spectroscope, and its material is to comprise liquid crystal; The spherical aberration correction device and comprises two clinohedrals between focus point and condenser lens, adjust the thickness of spherical aberration correction device by the mutual displacement of two clinohedrals; Photodetector detects the light beam that transmits from the polarization spectroscope.The present invention has also disclosed another kind of optical read/write head, and its spherical aberration correction device is between a focus point of a light source and optical read/write head.
By technique scheme, optical read/write head of the present invention has following advantage at least: a kind of optical read/write head of the present invention can be applied to the required light beams of different wavelengths of dissimilar optical data storage medias, and the optical data storage media that the spacing that can be applied to recording layer designs arbitrarily, and then increase compatibility and function.
From the above, because of according to a kind of optical read/write head of the present invention, has the spherical aberration correction device that to adjust thickness.Compare with known techniques, the spherical aberration correction device cording that optical read/write head of the present invention had has two clinohedrals, mutual displacement by clinohedral, and then the thickness of change spherical aberration correction device, with in response to the condenser lens of light beams of different wavelengths via different numerical apertures, and focus to the recording layer of different spacing or dissimilar optical data storage medias and the spherical aberration that produces, make light beam can accurately focus on optical read/write head and want the recording layer read and write.In addition, when the dissimilar optical data storage media of optical read/write head desire read-write, and when having changed the wavelength of light beam, optical read/write head also has an optical compensatory element, its material system comprises liquid crystal, changes the arrangement mode of liquid crystal molecule by the difference of input voltage, and then changes refractive index, allowing light beams of different wavelengths to convert linearly polarized light or circularly polarized light to, and then penetrate the polarization spectroscope fully and received by photodetector.Therefore, a kind of optical read/write head of the present invention can be applied to the required light beams of different wavelengths of dissimilar optical data storage medias, and can be applied to the optical data storage media of any design of spacing of recording layer, and then increases compatibility and function.
In sum, the present invention has above-mentioned plurality of advantages and practical value, no matter it all has bigger improvement on product structure or function, have technically than much progress, and produced handy and practical effect, and more existing optical read/write head has the multinomial effect of enhancement, thus be suitable for practicality more, and have the extensive value of industry, really be a new and innovative, progressive, practical new design.
Above-mentioned explanation only is the general introduction of technical solution of the present invention, for can clearer understanding technological means of the present invention, and can be implemented according to the content of instructions, and for above-mentioned and other purposes, feature and advantage of the present invention can be become apparent, below especially exemplified by preferred embodiment, and conjunction with figs., be described in detail as follows.
Description of drawings
Fig. 1 is a kind of synoptic diagram of known optical read/write head.
Fig. 2 is the synoptic diagram according to a kind of optical read/write head of first embodiment of the invention.
Fig. 3 is the synoptic diagram according to the another kind of optical read/write head of first embodiment of the invention.
Fig. 4 is the synoptic diagram according to the spherical aberration correction device of a kind of optical read/write head of first embodiment of the invention.
Fig. 5 is a kind of synoptic diagram with optical data storage media of plural recording layer.
Fig. 6 is the synoptic diagram according to the optical compensatory element of a kind of optical read/write head of first embodiment of the invention.
Fig. 7 is the synoptic diagram according to a kind of optical read/write head of second embodiment of the invention.
1,2,2 ', 3: optical read/write head 11,21,31: light source
12,22,32: collimation lens 13,23,33: polarization spectroscope
14: quarter- wave plate 15,25,25a, 25b, 25c, 35: condenser lens
16,27,37: photodetector 17: optical sheet
24,34: optical compensatory element 241,242: glass substrate
243: nematic crystal 26,36: spherical aberration correction device
261: clinohedral 2611: inclined-plane
28: displacement micro-actuator D, D ': optical data storage media
L
1: the first recording layer L
N: the N recording layer
S: wall t: thickness
V: voltage
Embodiment
Reach technological means and the effect that predetermined goal of the invention is taked for further setting forth the present invention, below in conjunction with accompanying drawing and preferred embodiment, to its embodiment of optical read/write head, structure, feature and the effect thereof that foundation the present invention proposes, describe in detail as after.
By the explanation of embodiment, when can being to reach technological means that predetermined purpose takes and effect to get one more deeply and concrete understanding to the present invention, yet appended graphic only provide with reference to the usefulness of explanation, be not to be used for the present invention is limited.
See also shown in Figure 2ly, a kind of optical read/write head 2 of first embodiment of the invention is to comprise a light source 21, collimation lens 22, a polarization spectroscope 23, an optical compensatory element 24, a condenser lens 25, a spherical aberration correction device 26 and a photodetector 27.
The light beam that collimation lens 22 collimated light sources 21 are sent, and be directional light with beam collimation.Collimation lens 22 more can be connected to an actuator (figure show), and it adjusts collimation lens 22 with collimated light beam more accurately.
Optical compensatory element 24 comprises liquid crystal, by the rotation of liquid crystal molecule, so that the phase pushing figure of light beam one 90 degree to be provided.Light beam is converted into the linearly polarized light that s polarizes via polarization spectroscope 23, goes forward side by side into optics compensating element, 24.When the slow axis (slow axis) of the liquid crystal in light beam and the optical compensatory element 24 or fast axle (a fast axis) become 45 to spend when entering, because light beam equates at the component of level and vertical direction, therefore when the phase phasic difference 90 between the component of level and vertical direction is spent, light beam can convert a circularly polarized light to, and penetrates condenser lens 25.
Light beam is focused lens 25 and focuses on, and via spherical aberration correction device 26, with a recording layer (figure does not show) that focuses to an optical data storage media D.Light beam is via a reflection horizon (the figure does not show) reflection of optical data storage media D then, and the polarised direction of the circularly polarized light of this reflection is opposite with the polarised direction of the circularly polarized light of incident.After passing through optical compensatory element 24 again, become linearly polarized light, the polarised direction of the polarised direction of this linearly polarized light and the linearly polarized light of incident is a quadrature, i.e. the p polarised direction.After directly penetrating polarization spectroscope 23, detected by photodetector 27, to obtain the stored data of optical data storage media D.
In the present embodiment, condenser lens 25 is the hologram methods of can arranging in pairs or groups, with a holographic optics (Holographic Optical element, HOE) be arranged at condenser lens 25 before, also holographic optics directly can be made on the condenser lens 25, when making light beam pass through condenser lens 25, the required different numerical aperture of optical data storage media that the energy foundation is different, and focus on optical data storage media D.This is a known techniques, repeats no more here.In the present embodiment, condenser lens 25 can be connected to an actuator (figure show), in order to location condenser lens 25, and the distance that condenser lens 25 is maintained fixed with the recording layer that will read and write at any time.
See also shown in Figure 3ly, be another kind of embodiment, optical read/write head 2 ' is to have plural condenser lens 25a, 25b, 25c, and present embodiment is an example with three.Cooperate different optical data storage media D, plural number condenser lens 25a, 25b, 25c have different numerical apertures respectively, make light beam can see through the condenser lens of different numerical apertures and focus on, for example: when optical data storage media D was laser disc, then using numerical aperture was 0.45 condenser lens 25a; When optical data storage media D was digital video disc, then using numerical aperture was 0.6 condenser lens 25b; When optical data storage media D was Blu-ray Disc, then using numerical aperture was 0.85 condenser lens 25c.Condenser lens 25a, 25b, 25c also can connect an actuator (figure does not show), utilize actuator to locate condenser lens 25a, 25b, 25c, make light beam pass through a wherein condenser lens, and make condenser lens 25a, 25b, 25c and distance that the recording layer that will read and write is maintained fixed.
See also Fig. 2 and shown in Figure 4, spherical aberration correction device 26 is between optical data storage media D and condenser lens 25.Spherical aberration correction device 26 comprises that 261, two clinohedrals 261 of two clinohedrals (inclined objects) are to can be wedge shape (wedge-like) body or triangle body.Can adjust the thickness t of spherical aberration correction device 26 by the mutual displacement of clinohedral 261, when making light beam pass through clinohedral 261, have different optical path length to revise spherical aberration.Wherein, the material of clinohedral 261 can be the high materials of light transmittance such as glass, plastic cement or polycarbonate.Clinohedral 261 is to have an inclined-plane 2611 respectively, and clinohedral 261 is 2611 relative displacements along the inclined-plane respectively.Be noted that clinohedral 261 is to be in contact with one another or not contact mutually, and carry out relative displacement, but inclined-plane 2611 palpuses keep parallel to each other.As shown in Figure 4, if the area that two inclined-planes 2611 occur simultaneously is bigger, then the thickness t of spherical aberration correction device 26 becomes big gradually; If the area that two inclined-planes 2611 occur simultaneously is littler, then the thickness t of spherical aberration correction device 26 diminishes gradually.Wherein, the thickness t of spherical aberration correction device is not comprise two spaces between the clinohedral 261.
Please consult shown in Figure 2 again, in the present embodiment, optical read/write head 2 more comprises a displacement micro-actuator 28, can be in order to adjust the mutual displacement of clinohedral 261, and the thickness t of change spherical aberration correction device 26, to revise spherical aberration, make optical read/write head 2 be applicable to the optical data storage media D that the spacing of recording layer designs arbitrarily.In addition, when spherical aberration did not need to be corrected, spherical aberration correction device 26 can also be removed from light path.
Seeing also shown in Figure 5ly, is example with the optical data storage media D ' with pluratity of recording layers, supposes that light beam focuses on the first recording layer L
1The time, the thickness t of spherical aberration correction device 26 is 0, the thickness that light beam passes through optical data storage media D ' is t (1); When light beam focuses on the N recording layer, light beam the thickness of process be t (N).In addition, between each recording layer, a wall (space layer) S is arranged all.So that light beam can focus to the N recording layer, displacement micro-actuator 28 makes clinohedral 261 mutual displacements in order to revise spherical aberration, to change the thickness t of spherical aberration correction device 26.At this moment, the thickness of spherical aberration correction device 26 is t, then:
t＝[t(1)-t(N)]n(s)/n
Wherein, n (s) is the refraction coefficient of wall S; N is the refraction coefficient of clinohedral 261; T is the thickness (not comprising two spaces between the clinohedral 261) of two clinohedral 261 laps.If the folding coefficient of each wall S is not simultaneously, then:
t＝∑
i[t(i)-t(i+1)]n(s
i)/n i＝1，2，...，N-1
Wherein, n (s
i) be the refraction coefficient of the wall S between i recording layer and the i+1 recording layer; T (i) is a light beam when arriving the i recording layer, the thickness of process; T (i+1) is a light beam when arriving the i+1 recording layer, the thickness of process.Wherein, t (i) is greater than t (i+1).
In addition, different types of optical data storage media has the substrate of different-thickness, and for example the substrate thickness of laser disc is 1.1 to 1.2mm; The substrate thickness of digital video disc is about 0.6mm; The substrate thickness of Blu-ray Disc is about 0.1mm.The spherical aberration that substrate produced of these different-thickness, also available spherical aberration correction device 26 is revised.
See also shown in Figure 6, optical compensatory element 24 is to can be a liquid crystal retardation device (LC Retarder), comprise two glass substrates 241,242, has nematic crystal (NematicLiquid Crystal) 243 between the glass substrate 241,242, so-called nematic crystal be meant the molecular axis of each liquid crystal molecule all be parallel to each other outside, and no matter the direction unanimity is in stationary state or process of flowing, and molecule is kept basic arrangement mode parallel to each other and in the same way forever.Glass substrate the 241, the 242nd is coated with a transparent conductive film (figure does not show) respectively at the surface, and the material of conductive film is to be tin indium oxide (Indium TinOxide).Conductive film on the glass substrate 242 is a ground connection, and the conductive film on another glass substrate 241 is to give a voltage V.When a linearly polarized light will convert a circularly polarized light to, between the component of its polarised direction quadrature, need the phase differential of one 90 degree; Otherwise, when a circularly polarized light will convert a linearly polarized light to, also need the phase differential of one 90 degree.Change the arrangement mode of liquid crystal molecule by the difference of input voltage V, and then change refractive index,, and reach the function of polarization conversion so that light beams of different wavelengths can obtain the phase deviation of one 90 degree in optical compensatory element 24.
In the present embodiment, light beam is in regular turn by light source 21 process collimation lenses 22, polarization spectroscope 23, optical compensatory element 24, condenser lens 25, spherical aberration correction device 26, optical data storage media D, spherical aberration correction device 26, condenser lens 25, optical compensatory element 24, polarization spectroscope 23 and photodetector 27.
Then, see also shown in Figure 7ly, the optical read/write head 3 of second embodiment of the invention is to comprise a light source 31, collimation lens 32, a polarization spectroscope 33, an optical compensatory element 34, a condenser lens 35, a spherical aberration correction device 36 and a photodetector 37.Wherein, light source 31, collimation lens 32, polarization spectroscope 33, optical compensatory element 34, condenser lens 35 and photodetector 37 are to have identical technical characterictic and effect with light source 21, collimation lens 22, polarization spectroscope 23, optical compensatory element 24, condenser lens 25 and the photodetector 27 of first embodiment respectively, repeat no more in this.Different is that in first embodiment, spherical aberration correction device 26 is between optical data storage media D and condenser lens 25; And in the present embodiment, spherical aberration correction device 36 is between polarization spectroscope 33 and optical compensatory element 34.
In the present embodiment, spherical aberration correction device 36 is to can be an optical beam expander (Beam Expander) or a liquid crystal corrector (Liquid Crystal Corrector).Wherein optical beam expander can be made up of two positive lenss or a positive lens and a negative lens, can eliminate spherical aberration by changing the distance between two lens; The liquid crystal corrector is to have a liquid crystal panel (Liquid Crystal Panel), can eliminate spherical aberration by the voltage of adjusting its electrode.These two kinds are all known techniques, repeat no more here.
In first embodiment, spherical aberration correction device 26 of the present invention can receive the light beam that is focus state and revise spherical aberration, when reception is the light beam of focus state, can use as the spherical aberration correction device among first embodiment, and it is to have two clinohedrals.In a second embodiment, spherical aberration correction device 36 of the present invention can receive the parallel light beam that is not focused as yet and revise spherical aberration, so spherical aberration correction device of the present invention can be arranged at other position between light source and the optical data storage media.When receiving the parallel light beam be not focused as yet, the spherical aberration correction device can be positioned between condenser lens 35 and the optical compensatory element 34, use as second embodiment in optical beam expander or the liquid crystal corrector with the correction spherical aberration.
In sum, because of according to a kind of optical read/write head of the present invention, be to have the spherical aberration correction device that to adjust thickness.Compare with known techniques, the spherical aberration correction device that optical read/write head of the present invention had is to have two clinohedrals, mutual displacement by clinohedral, and then the thickness of change spherical aberration correction device, with in response to the condenser lens of light beams of different wavelengths via different numerical apertures, and focus to the recording layer of different spacing or dissimilar optical data storage medias and the spherical aberration that produces, make light beam can accurately focus on optical read/write head and want the recording layer read and write.In addition, when the dissimilar optical data storage media of optical read/write head desire read-write, and when having changed the wavelength of light beam, optical read/write head also has an optical compensatory element, its material is to comprise liquid crystal, changes the arrangement mode of liquid crystal molecule by the difference of input voltage, and then changes refractive index, allowing light beams of different wavelengths to convert linearly polarized light or circularly polarized light to, and then penetrate the polarization spectroscope fully and received by photodetector.In addition, the condenser lens of hologram method is used in collocation one, or plural condenser lens with different numerical apertures, to obtain required numerical aperture.Like this, a kind of optical read/write head of the present invention can be applied to the optical data storage media of any design of spacing of recording layer, and can be applied to dissimilar optical data storage medias, and then increases compatibility and function.
The above, it only is preferred embodiment of the present invention, be not that the present invention is done any pro forma restriction, though the present invention discloses as above with preferred embodiment, yet be not in order to limit the present invention, any those skilled in the art, in not breaking away from the technical solution of the present invention scope, when the technology contents that can utilize above-mentioned announcement is made a little change or is modified to the equivalent embodiment of equivalent variations, in every case be the content that does not break away from technical solution of the present invention, according to technical spirit of the present invention to any simple modification that above embodiment did, equivalent variations and modification all still belong in the scope of technical solution of the present invention.
Claims (10)
1, a kind of optical read/write head is characterized in that it comprises:
One light source is launched a light beam;
One collimation lens collimate this light beam;
One polarization spectroscope separates this light beam according to polarised direction;
At least one condenser lens focuses on this light beam to one focus point;
One optical compensatory element, between this focus point and this polarization spectroscope, this optical compensatory element is to comprise liquid crystal;
One spherical aberration correction device between this focus point and this condenser lens, and comprises two clinohedrals, adjusts the thickness of this spherical aberration correction device by the mutual displacement of these two clinohedrals; And
One photodetector detects this light beam that transmits from this polarization spectroscope.
2, optical read/write head according to claim 1 is characterized in that wherein said light source is a blue laser diode or a red laser diode.
3, optical read/write head according to claim 1 it is characterized in that wherein said optical compensatory element comprises two glass substrates, and liquid crystal places between this glass substrate.
4, optical read/write head according to claim 1, it is characterized in that wherein said optical compensatory element provides the phase pushing figure of these light beam one 90 degree, when this light beam is a linearly polarized light, then this Beam Transformation is become a circularly polarized light, maybe when this light beam is a circularly polarized light, then with this Beam Transformation being aligned polarized light.
5, optical read/write head according to claim 1, the material that it is characterized in that wherein said spherical aberration correction device is polycarbonate, plastic cement or glass.
6, optical read/write head according to claim 1 is characterized in that wherein said clinohedral has an inclined-plane respectively, and these clinohedrals are respectively along this inclined-plane relative displacement.
7, optical read/write head according to claim 1 is characterized in that wherein said clinohedral is two sphenoids or is two triangle bodies.
8, optical read/write head according to claim 1 is characterized in that it comprises:
One displacement micro-actuator is in order to adjust the mutual displacement of these clinohedrals, to change the thickness of this spherical aberration correction device.
9, optical read/write head according to claim 1, it is characterized in that wherein said focus point is positioned at an optical data storage media, this optical data storage media comprises one first recording layer, a wall and one second recording layer, this wall is between this first recording layer and this second recording layer, and the thickness of this wall is t
s, refraction coefficient is n (s), and this light beam is t by thickness, and refraction coefficient is this spherical aberration correction device of n, then t, t
s, n (s), n meet following equation:
t＝t
s*n(s)/n。
10, optical read/write head according to claim 9 is characterized in that wherein said light beam is passed through in regular turn by this light source: this collimation lens, this polarization spectroscope, this optical compensatory element, this condenser lens, this spherical aberration correction device, this optical data storage media, this spherical aberration correction device, this condenser lens, this optical compensatory element, this polarization spectroscope and this photodetector.
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|---|---|---|---|
| CNB200610058292XA CN100466075C (en) | 2006-03-02 | 2006-03-02 | Optical read/write head |
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| CNB200610058292XA CN100466075C (en) | 2006-03-02 | 2006-03-02 | Optical read/write head |
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| Publication Number | Publication Date |
|---|---|
| CN101030406A CN101030406A (en) | 2007-09-05 |
| CN100466075C true CN100466075C (en) | 2009-03-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB200610058292XA Expired - Fee Related CN100466075C (en) | 2006-03-02 | 2006-03-02 | Optical read/write head |
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| CN (1) | CN100466075C (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1591624A (en) * | 2003-08-27 | 2005-03-09 | 三美电机株式会社 | Spherical aberration corrector plate,optical reading device using the same and correcting method |
| CN1717599A (en) * | 2002-11-29 | 2006-01-04 | 旭硝子株式会社 | Phase plate and an optical data recording/reproducing device |
| CN1734600A (en) * | 2004-08-13 | 2006-02-15 | 上海乐金广电电子有限公司 | Spherical aberration correction apparatus for optical pick-up device |
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2006
- 2006-03-02 CN CNB200610058292XA patent/CN100466075C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1717599A (en) * | 2002-11-29 | 2006-01-04 | 旭硝子株式会社 | Phase plate and an optical data recording/reproducing device |
| CN1591624A (en) * | 2003-08-27 | 2005-03-09 | 三美电机株式会社 | Spherical aberration corrector plate,optical reading device using the same and correcting method |
| CN1734600A (en) * | 2004-08-13 | 2006-02-15 | 上海乐金广电电子有限公司 | Spherical aberration correction apparatus for optical pick-up device |
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| CN101030406A (en) | 2007-09-05 |
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