CN100419882C

CN100419882C - Optical read/write system

Info

Publication number: CN100419882C
Application number: CNB200410028182XA
Authority: CN
Inventors: 孙文信
Original assignee: Hongfujin Precision Industry Shenzhen Co Ltd; Hon Hai Precision Industry Co Ltd
Current assignee: Hongfujin Precision Industry Shenzhen Co Ltd; Hon Hai Precision Industry Co Ltd
Priority date: 2004-07-17
Filing date: 2004-07-17
Publication date: 2008-09-17
Anticipated expiration: 2024-07-17
Also published as: CN1722258A

Abstract

The present invention relates to an optical reading and writing system which can record and reproduce signals of a first optical disk size, a second optical disk size and a third optical disk size. The storage densities of the first optical disk size, the second optical disk size and the third optical disk size decrease orderly. The optical reading and writing system comprises a first light source, a second light source and a third light source which respectively emit a first incident light beam, a second incident light beam and a third incident light beam with a first wavelength, a second wavelength and a third wavelength, a prism unit, a collimating lens and an object lens, wherein the second wavelength is larger than the first wavelength, and the third wavelength is larger than the second wavelength. The prism unit is provided with a first light inlet surface, a second light inlet surface in an aspheric surface structure for inputting the third incident light beam, and a light outlet surface for outputting the first incident light beam, the second incident light beam and the third incident light beam from the same position. The first light inlet surface comprises a first light inlet area and a second light inlet area respectively arranged corresponding to a first light sending and receiving unit and a second light sending and receiving unit, and the second light inlet area is in an aspheric surface structure. The collimating lens is positioned in a light path of one side of the light outlet surface of the prism unit, and the collimating lens and the object lens both have optical parameters matched with the first optical disk size.

Description

The optical read/write system

[technical field]

The invention relates to a kind of optical read/write system that is used for data recording/reproducing device, refer to a kind of optical read/write system of compatible different discs specification especially.

[background technology]

The specific wavelength light signal that the optical read/write system sends light source by a specific light path is focused on the CD and forms a hot spot, realizes the read/write operation to CD thus.Along with the continuous evolution of CD specification from CD, DVD to HD-DVD, the optical disc data recording density is more fine and close, and this just requires the hot spot of disk read/write information littler.And the size of hot spot is closely linked with the numerical aperture (NA) of optical maser wavelength and object lens, and the size of hot spot is proportional to Wavelength of Laser, is inversely proportional to the numerical aperture (NA) of object lens.So, the CD specification causes the laser light wavelength constantly to reduce constantly to increase with the numerical aperture (NA) of object lens to high density evolution meeting.Wavelength, numerical aperture (NA) are as shown in the table with the concrete variation of CD specification:

The CD specification	CD	DVD	HD-DVD
The CD specification	CD	DVD	HD-DVD	Wavelength	780nm	650nm	405nm
Numerical aperture (NA)	0.45	0.6	0.65 or 0.8	Wavelength	780nm	650nm	405nm

Because the optical parametric difference of different discs specification causes the compatibility issue of each specification to become outstanding.The optical disc information of read/write specific standard just must use the optical element that meets this kind CD specification, otherwise, can reduce read.Yet, desire in a cover optical read/write device, to realize the read/write operation of plurality of specifications CD at the corresponding optical read/write of each specifications design system, is shown non-wise move.Its optical system complexity had not only caused the read/write device volume excessive but also cost is increased.

Existingly in the prior art adopt mode to reduce optical element quantity with the optical system common sparing light path of corresponding different size, and optic path elements such as common shared collimation lens, object lens.But the optical parametric of optical element is normally by decisions such as shape, materials, and it is fixing unadjustable.Such as collimation lens, it has light-focusing function, but it only changes into parallel beam to the divergent beams of a certain specific wavelength, and the light beam of other wavelength then only can change into approximate parallel beam.Object lens also are like this, it only can converge at its correspondence position well with the parallel beam of specific wavelength of input, and other wavelength is assembled to other position, promptly can there be certain error owing to not matching in this, as spherical aberration, aberration phenomenon in the aberration appear, or the area of focal beam spot is too big, thereby influences the optical property of optical system and the information on the recording/reproducing optical disk correctly.Optical read/write system as above-mentioned HD-DVD data recording/reproducing device, corresponding HD-DVD, DVD and CD specification are provided with light source and optical receiver respectively, and need to be provided with in the optical read/write system that a light path coupling element makes can shared part light path from the light beam of Different Light.Shared collimation lens and object lens only can be at wherein a kind of specification settings, and as setting at the HD-DVD specification, then phenomenons such as spherical aberration, aberration will appear in the light path of DVD and CD specification.

[summary of the invention]

The object of the present invention is to provide a kind of optical read/write system, but the multiple CD specification of its recoding/reproduction, and the aberration that light path but also recoverable optical element do not match and cause not only can have been simplified by this optical read/write system.

A kind of optical read/write system, but its recoding/reproduction first, the signal of second and third CD specification, and the storage density of CD specification successively decreases successively, this optical read/write system comprises one first smooth Transmit-Receive Unit, one second smooth Transmit-Receive Unit, one the 3rd smooth Transmit-Receive Unit, one prism unit, one collimation lens and object lens, this first smooth Transmit-Receive Unit has first light source that can send first incident beam of first wavelength, this second smooth Transmit-Receive Unit has a secondary light source that can send second incident beam of second wavelength, the 3rd smooth Transmit-Receive Unit has the 3rd light source that can send the 3rd incident beam of three-wavelength, wherein this second wavelength greater than this three-wavelength of first wavelength greater than second wavelength, this prism unit has an input first, first incidence surface of second incident beam, one non-spherical structure and be oppositely arranged with second incidence surface of importing the 3rd incident beam and via same position output first with the 3rd smooth Transmit-Receive Unit, second, the 3rd goes into the exiting surface of light beams, this first incidence surface comprises respectively with first, the second smooth Transmit-Receive Unit is oppositely arranged with input from first of different light paths, first of second incident beam, second light incidence section, and this second light incidence section is a non-spherical structure, this collimation lens is arranged in the light path of exiting surface one side of prism unit, and has the optical parametric that is complementary with the 3rd incident beam, these object lens are over against the optical disc surface setting, and these object lens have the optical parametric that is complementary with the first CD specification.

Compared with prior art, the present invention has the following advantages: at first, optical read/write of the present invention system adopts the prism unit of three light incidence sections of a tool to import from different incidence surfaces from the different wave length light signal of Different Light, and by same exiting surface output, thereby it is different optical is system coupled with shared part light path, therefore can simplify light path, reduce the number of optical elements of optical read/write system, thereby reduce the encapsulation volume of optical read/write system and reduce the cost of optical read/write system.Moreover the collimation lens of optical read/write of the present invention system and the optical parametric of object lens all are complementary with the standard that the first CD specification is formulated, so during the recoding/reproduction first CD specification data, the optical read/write system has the good optical performance.And optical read/write of the present invention system also adds an aspherical optical element respectively in the light path of second, third incident beam, thereby the aberration that correcting optical element does not match and causes.

[description of drawings]

Fig. 1 is an optical read/write system schematic of the present invention.

Fig. 2 is the prism group vertical view of optical read/write system.

Fig. 3 A is the vertical view that Fig. 1 optical read/write system wavelength is selected mirror.

Fig. 3 B is the light path synoptic diagram of Fig. 3 A wavelength-selective mirror.

[embodiment]

See also Fig. 1, it is the synoptic diagram of optical read/write of the present invention system 100.Optical read/write of the present invention system 100 is applicable in the data recording/reproducing device of recoding/reproduction different discs specification that present embodiment is the example explanation with the optical read/write system that is applicable to the HD-DVD data recording/reproducing device.Optical read/write system 100 comprises the smooth Transmit-Receive Unit of the smooth Transmit-Receive Unit of one first smooth Transmit-Receive Unit 11, one second 12, the 3rd 13, one first diffraction element 21, one second diffraction element 22, one the 3rd diffraction element 23, a prism group 3, collimation lens 4, catoptron 5, a wavelength-selective mirror 6 and object lens 7.Wherein, first smooth Transmit-Receive Unit 11, second smooth Transmit-Receive Unit the 12, the 3rd smooth Transmit-Receive Unit 13, the first diffraction elements 21, second diffraction element 22, the 3rd diffraction element 23, prism group 3 can be integrated encapsulation by semiconductor technology.

These first, second and third smooth Transmit-

Receive Unit

11,12 and 13 parallel being set up in parallel, and the first smooth Transmit-Receive Unit 11 has one first light source 11a, one first detecting device 11b, the second smooth Transmit-Receive Unit 12 comprises a secondary light source 12a, one second detecting device 12b, and the 3rd smooth Transmit-Receive Unit 13 comprises one the 3rd light source 13a, one the 3rd detecting device 13b.The first light source 11a sends first incident beam with first wavelength, and the first detecting device 11b detects first Returning beam that this first incident beam is formed by CD reflection.Secondary light source 12a sends second incident beam with second wavelength, and the second detecting device 12b detects second Returning beam that this second incident beam is formed by CD reflection.The 3rd light source 13a sends the 3rd incident beam with three-wavelength, and the 3rd detecting device 13b detects the 3rd Returning beam that the 3rd incident beam is formed by CD reflection.Wherein, first, second and third wavelength is respectively the ruddiness of blue light that wavelength is the read/writable HD-DVD specification CD of 405nm, read/writable DVD specification CD that wavelength is 650nm and the near infrared light of the read/writable CD specification CD that wavelength is 780nm.

This first diffraction element 21, second diffraction element 22 and the 3rd diffraction element 23 are provided with over against first, second and

third light source

11a, 12a, the 13a of first, second and third Transmit-Receive

Unit

11,12,13 respectively.

See also Fig. 2, it is the vertical view of optical read/write of the present invention system 100 prism groups 3.Described prism group 3 comprises one first prism 31, one second prism 32 and a prism 33, and first,

second prism

31,32 is positioned at prism 33 phase the same sides.First, second,

third prism

31,32,33 is approximate quadrangular structure.First prism 31 has first incidence surface 310 that is oppositely arranged is connected this first incidence surface 310 and first exiting surface 311 with first exiting surface 311 and first reflecting surface 312, and this first reflecting

surface

312 and 311 tools of first exiting surface, one 135 degree angles.This first incidence surface 310 has first light incidence section 310a of a planar structure and the second light incidence section 310b of non-spherical structure, and wherein this first, second light incidence section 310a, 310b are provided with to import first, second incident beam respectively over against first,

second diffraction element

21,22 respectively.First prism 31 also has the first light path transition interface 313 that one and first reflecting surface 312 be arranged in parallel, and it is to the transmission of 405nm wavelength light signal, and to the signal reflex of 650nm wavelength light.Second prism 32 has second incidence surface 320 and second exiting surface 321 that is oppositely arranged, and this second incidence surface 320 is set to import the 3rd incident beam and to its correcting spherical aberration for non-spherical structure and over against the 3rd diffraction element 23.Prism 33 has the 3rd light path transition interface 333 that the 3rd parallel incidence surface 330 and the 3rd exiting surface 331, the 3rd reflecting surface 332 and that tilts to be connected the 3rd incidence surface 330 and the 3rd exiting surface 331 are parallel to the 3rd reflecting surface 332.Wherein, the 3rd incidence surface 330 is provided with over against first, second exiting surface 311,321 of first,

second prism

31,32, the 3rd reflecting

surface

332 and 330 tools of the 3rd incidence surface, 45 degree angles, the 3rd light path transition interface 333 has different reflections or transmission function at the incident light of different wave length.

Please consult Fig. 1 again, collimation lens 4 is provided with over against the 3rd exiting surface 331 of prism unit 3, and it has the optical parametric that the three-wavelength with the 3rd incident beam is complementary.Face catoptron 5 is obliquely installed between collimation lens 4 and wavelength-selective mirror 6, and tool 45 degree angles change into transmission vertically with first, second, third incident beam with the along continuous straight runs transmission between its optical axis and vertical direction.Object lens 7 are over against the CD setting, and it has the optical parametric that is complementary with first incident beam.

See also Fig. 3 A and Fig. 3 B, wavelength-selective mirror 6 is positioned at object lens 7 and deviates from optical disc surface one side, and it has a first area 61 that is positioned at its centre, around the second area 62 of first area 61 and around the 3rd zone 63 of second area 62.Wherein, all transmissions of light signal of first, second, third wavelength of the 61 pairs of inputs in first area, first, second wavelength light signal of second area 62 transmissions and stop the three-wavelength light signal, the 3rd zone 63 be the transmission first wavelength light signal and stop second, third wavelength light signal only.So, make object lens 7 satisfy the demand of HD-DVD, DVD and CD specification simultaneously by the light transmission in first, second,

third zone

61,62,63.

During read/write HD-DVD CD, the first light source 11a of first Transmit-Receive Unit 11 sends first incident beam with 405nm wavelength, and along first incidence surface 310 that is sent to first prism 31 after first diffraction element 21 is passed in its former transmission direction, and enter first prism, 31 inside via the first light incidence section 310a.First incident beam that enters first prism 31 is incident to the first light path transition interface 313.Because the transmission of 313 pairs of 405nm wavelength light of first light path transition interface signal, and to the signal reflex of 650nm wavelength light.Thereby this first incident beam is from 313 transmissions of the first light path transition interface and via 311 outgoing of first exiting surface.This first incident beam after enter prism 33 by the 3rd incidence surface 330, and is incident to the 3rd light path transition interface 333 from 311 outgoing of first exiting surface.Because 333 couples of 405nm of the 3rd light path transition interface and the transmission of 650nm wavelength light signal, and to the signal reflex of 780nm wavelength light, thus this first incident beam via the 3rd light path transition interface 333 along its former transmission direction transmission, and by 331 outgoing of the 3rd exiting surface.

Outgoing is to face catoptron 5 after changing into parallel beam from first incident beam of the 3rd exiting surface 331 outgoing of prism 33 via collimation lens 4, and 5 reflections of quilt cover catoptron, thereby its transmission direction is changed into vertical direction by horizontal direction.First incident beam of quilt cover catoptron 5 reflections is incident to wavelength-selective mirror 6.Because first, second,

third zone

61,62,63 of wavelength-selective mirror 6 is for all transmissions of 405nm wavelength light signal, thereby first incident beam can all be incident to object lens 7 by wavelength-selective mirror 6.Object lens 7 converge at first incident beam of parallel incident on the Information Level of HD-DVD CD (indicating).The HD-DVD CD reflects to form first Returning beam first incident beam of incident.This first Returning beam basic identical through the light path of the light path and first incident beam, its difference is that first Returning beam is incident to first diffraction element, 21 backs and is projected on the first detecting device 11b by its refraction, and this first detecting device 11b converts light signal to electric signal and exports interlock circuit to.

Because the optical parametric of the various optical elements that comprise in the light path of first incident beam and first folded light beam is all with reference to the HD-DVD specifications design.

During read/write DVD CD, secondary light source 12a sends second incident beam of 650nm wavelength, and this second incident beam enters first prism 31 of prism unit 3 by second diffraction element, 22 backs by the second light incidence section 310b along its former transmission direction.Because this second light incidence section 310b is a non-spherical structure, it has poly-rotary light performance to incident beam, and this second incident beam is incident to first reflecting surface 312 after assembling the first time of the second light incidence section 310b, and is reflexed to the first light path transition interface 313 by it.Because 313 pairs of 650nm wavelength light of first light path transition interface signal tool reflection function.Therefore, this second incident beam is reflected the back once more from 311 outgoing of first exiting surface.Simultaneously, because first reflecting surface 312 and the first light path transition interface 313 be parallel to each other, so, consistent from the exit direction of second incident beam of first exiting surface, 311 outgoing with incident direction from second incident beam of the second light incidence section 310b incident.Second incident beam after 31 outgoing of first prism is entered prism and is incident to the second light path transition interface 333 by the 3rd incidence surface 330.Because 333 pairs of 650nm light signals of second light path transition interface tool transmission function, thereby this second incident beam is from 333 transmissions of the second light path transition interface, and via 331 outgoing of the 3rd exiting surface.

Change into nearly parallel beam and be incident to face catoptron 5 via collimation lens 4 convergence for the second time from second incident beam of prism 33 outgoing.Second incident beam reflection of 5 pairs of incidents of face catoptron is to change into vertical transmission with its transmission direction by horizontal transport.Second incident beam that changes into after the vertical transmission is incident to wavelength-selective mirror 6.Because first,

second zone

61,62 pairs of 650nm wavelength light signals transmission of wavelength-selective mirror 6, the 63 pairs of 650nm wavelength light signals in the 3rd zone stop, thereby the light beam of the second incident beam outermost is blocked, and has only the light beam from 61,62 transmissions of first, second zone can be incident on the object lens 7.Thereby make object lens 7 satisfy the numerical aperture of DVD specification.Second incident beam of 7 pairs of incidents of object lens is assembled for the third time so that it is converged on the Information Level of DVD CD.The DVD CD reflects to form second Returning beam second incident beam of incident.This second Returning beam basic identical through the light path of the light path and second incident beam, its difference is that second Returning beam is incident to second diffraction element, 22 backs and is projected on the second detecting device 12b by its refraction, and this second detecting device 12b converts light signal to electric signal and exports interlock circuit to.

Although the optical parametric of collimation lens 4, object lens 7 is all with reference to the HD-DVD specifications design in second incident beam and the first incident beam light path, but its second light incidence section 310b aspheric surface collimation lens 4 by first prism 31 of prism unit 3, the optically focused performance of object lens 7 compensate, and make object lens 7 satisfy the numerical aperture of DVD specification, thereby can avoid in the optical system caused aberration because collimation lens, object lens do not match by wavelength-selective mirror 6.

During read/write CD CD, the 3rd light source 13a sends the 3rd incident beam with 780nm wavelength, and the 3rd incident beam enters second prism 32 of prism unit 3 by the 3rd diffraction element 23 backs by second incidence surface 320 along its former transmission direction.Because second incidence surface 320 is a non-spherical structure, it has certain light-focusing function to the 3rd incident beam.The 3rd incident beam that enters second prism 32 exports the 3rd incidence surface 330 of prism 33 to via second exiting surface 321, and reflexes to the 3rd light path transition interface 333 in the 3rd reflecting surface 332 of prism 33.333 pairs of 780nm wavelength light of the 3rd light path transition interface signal tool reflection function, and itself and the 3rd reflecting surface 332 parallel being oppositely arranged, so, the 3rd folded light beam through two secondary reflections after from 331 outgoing of the 3rd exiting surface, the direction of outgoing is with consistent from the direction of the 3rd incidence surface 330 incidents.

Change into nearly parallel beam and be incident to face catoptron 5 via collimation lens 4 convergence for the second time from the 3rd incident beam of prism 33 outgoing.The 3rd incident beam reflection of 5 pairs of incidents of face catoptron is to change into vertical transmission with its transmission direction by horizontal transport.The 3rd incident beam that changes into after the vertical transmission is incident to wavelength-selective mirror 6.Because wavelength-selective mirror 6 only can be passed through 780nm wavelength light signal in first area 61, thereby the light beam of the 3rd incident beam periphery all is blocked, and has only the light beam from first area 61 transmissions can be incident on the object lens 7.Thereby make object lens 7 satisfy the CD specification fixed numerical aperture.The 3rd incident beam of 7 pairs of incidents of object lens is assembled for the third time so that it is converged on the Information Level of CD CD.The CD CD reflects to form the 3rd Returning beam the 3rd incident beam of incident.The 3rd Returning beam basic identical through the light path of light path and the 3rd incident beam, its difference is that the 3rd Returning beam is incident to the 3rd diffraction element 23 backs and is projected on the 3rd detecting device 13b by its refraction, and the 3rd detecting device 13b converts light signal to electric signal and exports interlock circuit to.

Although the optical parametric of shared optical element is all with reference to the HD-DVD specifications design in the light path of the 3rd incident beam and first incident beam, but the 3rd incident beam is assembled for 7 three times via second incidence surface, 320 aspheric surfaces, collimation lens 4 and the object lens of second prism 32, and utilize wavelength-selective mirror 6, thereby effectively avoid in the optical system caused aberration because collimation lens, object lens do not match so that the 3rd incident beam satisfies the numerical aperture of CD specification.

Claims

1. optical read/write system, but its recoding/reproduction first, the signal of second and third CD specification, and the storage density of CD specification successively decreases successively, this optical read/write system comprises one first smooth Transmit-Receive Unit, one second smooth Transmit-Receive Unit, one the 3rd smooth Transmit-Receive Unit, one collimation lens and object lens, this first smooth Transmit-Receive Unit has first light source that can send first incident beam of first wavelength, this second smooth Transmit-Receive Unit has a secondary light source that can send second incident beam of second wavelength, the 3rd smooth Transmit-Receive Unit has the 3rd light source that can send the 3rd incident beam of three-wavelength, wherein this second wavelength greater than this three-wavelength of first wavelength greater than second wavelength, it is characterized in that: this optical read/write system also comprises a prism unit, this prism unit has an input first, first incidence surface of second incident beam, one non-spherical structure and be oppositely arranged with second incidence surface of importing the 3rd incident beam and with via same position output first with the 3rd smooth Transmit-Receive Unit, second, the 3rd goes into the exiting surface of light beams, this first incidence surface comprises respectively with first, the second smooth Transmit-Receive Unit be oppositely arranged first, first of second incident beam, second light incidence section, and this second light incidence section is a non-spherical structure, this collimation lens is arranged in the light path of exiting surface one side of prism unit, and has the optical parametric that is complementary with first incident beam, these object lens are over against the optical disc surface setting, and have the optical parametric that is complementary with the first CD specification.

2. optical read/write as claimed in claim 1 system, it is characterized in that: this prism unit has first, second, third prism, and this first, second prism is positioned at prism one side and parallel mutually the setting.

3. optical read/write as claimed in claim 2 system, it is characterized in that: this second prism has incidence surface and the exiting surface that is oppositely arranged, and this incidence surface exports prism for second incidence surface and the 3rd incident beam of this prism unit to via this exiting surface.

4. optical read/write as claimed in claim 2 system, it is characterized in that: this first prism has the incidence surface that is oppositely arranged is connected the incidence surface and first exiting surface with first exiting surface and first reflecting surface, this incidence surface is first incidence surface of prism unit, and this first reflecting surface is located at the end of first incidence surface away from its first light incidence section.

5. optical read/write as claimed in claim 4 system, it is characterized in that: this first prism also comprise one parallel with this first reflecting surface be oppositely arranged to the first wavelength light signal transmission and to the first light path conversion element of the second wavelength light signal reflex, this light path conversion element is positioned at the intersection of first, second light incidence section.

6. optical read/write as claimed in claim 2 system, it is characterized in that: this prism has incidence surface and the exiting surface that be arranged in parallel, the incidence surface of this prism and first, second prism are oppositely arranged, and the exiting surface of this prism is the exiting surface of prism unit.

7. optical read/write as claimed in claim 6 system is characterized in that: this prism has the 3rd reflecting surface of a pair of the 3rd incident beam reflection in the end near second prism.

8. optical read/write as claimed in claim 7 system is characterized in that: this prism comprises that also one is parallel to the 3rd reflecting surface and to first, second wavelength light signal transmission and to the 3rd light path conversion element of three-wavelength light signal reflection.

9. optical read/write as claimed in claim 1 system, it is characterized in that: this optical read/write system also comprises three diffraction elements, it is over against first, second, third light source setting, and this first, second, third smooth Transmit-Receive Unit, three diffraction elements and prism unit are packaged in one by semiconductor technology.

10. optical read/write as claimed in claim 1 system, it is characterized in that: this optical read/write system also comprises a wavelength-selective mirror, and this wavelength-selective mirror is positioned at object lens away from CD one side and the light signal that the comprises a pair of first, second, third wavelength first area, a pair of first, second wavelength light signal transmission of transmission and second area and that the three-wavelength light signal is stopped the 3rd zone of the transmission first wavelength light signal only all.