TW476947B - Optical pickup - Google Patents

Abstract

An optical pickup capable of effectively reducing chromatic aberration is provided. In the optical pickup, a collimating lens including a diverging lens with diverging power and a focusing lens with focusing power is arranged on the optical path between a light source and an objective lens, wherein assuming that the total focal distance of the collimating lens is f and the focal distance of the diverging lens is fn, the collimating lens satisfies the relationship -1.5 > f/fn. The optical pickup is compatible with both existing digital versatile disks (DVDs), and high-definition (HD)-DVDs, which are not standardized yet, but need a blue light source near 405 nm and an objective lens having a numerical aperture of 0.6 or more.

Description

Price | 6947

Description of the Invention (Printed by the Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economics [Background of the Invention] 1. Field of the Invention The present invention relates to a light pick-up for a high-density information writing and reading system 'and more particularly, to An optical pickup capable of reducing chromatic aberration occurs when a blue light source is used. 2. Description of Related Technology In an optical writing and reading system, the recording density is determined by the size of a focused light spot. In general, the size (s) of this focused spot is proportional to the wavelength (λ) and inversely proportional to the aperture (n A), which can be expressed by equation (1): " S and / NA. ........ (1) This is the focus for a higher recording density than that achieved in compact discs (CD s) or digital versatile discs (d VD s). The size of the light spot on a disc must be further reduced. To reduce the size of this wire, why is it deduced from the equation + + the wavelength of the light beam ⑴ must be reduced, and this object ^ So, for such a high density Information note = a laser beam with a short wavelength, for example In other words, a Lanxiandi 2 is used as a light source, and the aperture of this objective lens must be: Dimensions: In Figure 1 is a diagram showing that in terms of the double power loss of the laser diode 2, a laser diode The figure below Wen Erxia shows a picture of various optical material materials. Figure 2 "!!! ^ 图 η, magnification: -Special == ice sheet scale applicable specifications ⑵. X Again ------- -^ --------- ^ 1 ^ cPlease read the note on the back? Matters before filling out this page} 476947 A7 B7 V. Description of the invention (>) ^ Add 'This emission wavelength increases in proportion to , Which is a feature of laser diodes. As shown in Figure 2, the refractive index of various optical substances changes abruptly in a short wavelength region, for example, close to 400 nm, compared to that for small discs. 780 nm for films (C ds) and 650 nm for digital versatile discs (DVD s) ° When writing information to a disc, a desired position on this disc is searched by writing energy And then a record label is formed at this found position by increasing the writing energy. However, it is so sudden in terms of output energy The change causes chromatic aberration in the optical system, thereby defocusing the light spot on the disc. In addition, it takes a lot of time to correct this defocus by the control of a servo circuit. In other words, when A high frequency (ΗF) module is used to reduce the noise caused by the light beam reflected from a disc to a light source. The wavelength of the light beam emitted from this light source is increased, thereby increasing the chromatic aberration in this optical system. And, in particular, in this objective lens, this problem causes a reduction in the quality of a duplicated signal. In addition, it can be further considered, as seen in Chen Figure 1, the wavelength of the hair bundle can be picked up with the light here The temperature inside the device increases, and the change in wavelength caused by using different light sources changes the chromatic aberration. Various optical pickups (which have a light source with a wavelength of 650 and an objective lens) have been proposed to make them compatible with wake-up DVD s and 1.2 mm CD s. The technology in these proposed optical pickups is a kind of ring mask technology, which is used to block the passing of the middle area between the far axis and the paraxial region. % (Please read the precautions on the back before filling out this page) Order --------- Line — Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs to control the objective lens by using a liquid crystal (LC) shutter Tons, and

476947 A7 V. Description of the Invention (β) A hologram optical element (ZOE) technology is used to split a light using a holographic optical element (ZOE) to form a single focus on two magnetic disks having different thicknesses. However, for a small recordable disc (c D ~ R), the reflectivity of this red light source suddenly drops, and therefore a light source having a wavelength of 78 nm is required. For this reason, the use of a DVD-unlimited / CD-limited optical system provides a valley between beams of 78nm & 65nm, or a ring-shaped focus region with a far-axis and a paraxial region. The use of objective lenses has been proposed. In particular, for the -cD-limited optical system, the aperture of the objective lens is limited and the divergent beam is projected on the objective lens, thereby correcting aberrations caused by the difference in the thickness of the magnetic disk and the objective lens. An optical pickup using a short-wavelength light source is required for the writing and reading of higher density information than can be achieved by a D V D system. As in the same example, a laser beam with a wavelength shorter than 650 nm used by d V D s is required as a light source for one of the optical pickups used for H D — D V D s. However, as previously explained and referenced to Fig. 2, because the refractive index of the optical substance of this magnetic disk suddenly, aerates at wavelengths shorter than 650 nm, excessive aberrations occur. Therefore, there is a need for an optical system that is compatible with today's DVD s and can effectively reduce chromatic aberration. For a DVD-R, there is a reduction in the reflectance of a light source different from the red light source. Therefore, for compatibility with DVD-R s, a light source with a wavelength of 650 nm must be further used. However, the problem of this aberration cannot be ruled out by controlling only the divergence of the light beam emitted from the 650 nm light source and projected on the objective lens. Therefore, in the development of HD — this paper is suitable for the standard size ⑵ χ 297 mm) page order " f / 6947 V. Description of the invention (y) =: The key problem in the capacity system is to find an effective chromatic aberration description In = and: J]] the lens objective lens consists of two lenses-the first-== 3 'is arranged on-disk 6 and used to focus the first two 2]] This structure is not visible in Figure 3 allows the aperture to increase To 0.7 or so 'such-an objective lens can be used in high-density: optical systems. However, this objective lens has problems in using two lenses to increase the length of the optical path, and the reproduction of the beam spot is highly sensitive to a change in the position.

In order to solve the above problems, an object of the present invention is to provide an optical pickup that uses different short-wavelength laser beams as a light source. D Another object of the present invention is to provide an optical pickup which can effectively correct aberrations caused by a sudden change in the refractive index of an optical substance. Still another object of the present invention is to provide an optical pickup that uses a laser beam of 650 nm for digital versatile discs (DVD s) and a laser of about 400 nm for HD-DVD s The light beam is made to be compatible with other optical recording media. According to an aspect of the present invention, the present invention provides an optical pickup including a light source for generating a laser beam of 500 nm or less;-4/0 ^ / 4/0 ^ / Intellectual Property Bureau of the Ministry of Economic Affairs Printed by employee consumer cooperative A7 V. Description of the invention (f) An objective lens is used to focus the laser beam on the laser beam reflected on the disc to become an electron two and right and Gong and Γ, which are arranged in Between this light source and the objective lens, it includes: = astigmatism lens and a focusing lens with focusing magnification, ik, the total focal length of this alignment lens is f, and the focal length of this astigmatic lens is fn, this alignment The lens conforms to the relationship 1.5 > f / fn. Another, viewpoint of the sun and the moon. The present invention provides a kind of optical pickup package and a first light source, which respectively correspond to the first and second media, and generate a laser beam of 3 wavelengths; The objective lens is used to separately focus the f-ray beams from the second and second light sources on the first and second t; the first and second detectors are used to separately receive the first and second Brother-the laser beam emitted by the light source and the laser beam reflected from the first and second media; and-an alignment lens arranged in the optical path of one of the laser beams having a relatively short wavelength In the above, the alignment lens includes a astigmatism lens with a divergent magnification and a focus lens with a focus magnification, where it is assumed that the total focal length of the alignment lens is f and the focal length of the astigmatic lens is fn. The alignment lens conforms to Relation one 1.5 > f / fn. According to another aspect of the present invention, the present invention provides an optical pickup including: an objective lens arranged to face the first and second media; a first light source arranged on a light path of the objective lens; A beam splitter arranged between the objective lens and the first light source; a second light source arranged on the light path of the light beam reflected from the beam splitter; a first phase detector for receiving from The laser beam emitted by the first light source and the laser beam reflected from the first medium; a second phase detector is used to receive the first light source (please read the precautions on the back before filling this page) · 11111111 1 ^ A7 A7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 5. Description of the invention (& =: ΐ ΐ and the laser beam reflected from this second medium; and =-: r astigmatism astigmatism. The total focal length of the alignment lens is f Ϊ ^ The focal length is avoided, and the alignment lens conforms to the relationship, -bf / fn According to another aspect of the present invention, the present invention provides:-an objective lens, which is arranged facing the first 1st and 2nd media; 2nd 2nd skin is arranged at On the light path of the objective lens, it is used to emit a laser light = to the first optical disc; the first, second and third beam splitters, which: ^ by this brother-the light source is directed to the predetermined position of the objective lens On the path. — Twenty-two light sources, which are arranged on this first 丄: path, are used to emit a laser light. East longitude two =: = Diyi media; a first phase detector, which is arranged here. On the light path of the beam reflected by the third beam splitter, it is used to receive the laser beam reflected from the first light source and the laser beam reflected from the first medium; a second, measured as being arranged here On the optical path of the reflected light beam of the second beam splitter, 'for receiving the laser beam emitted from the second light source and the laser beam reflected from the two media; and-a decomposing lens, which is arranged on the objective lens and Between the third beam splitter, the alignment lens includes a astigmatism lens with a divergence ratio and a focusing lens with a focusing magnification, and the total focal length of the alignment lens at f is δ, and the astigmatism lens The focal length is 缶, and this alignment lens conforms to the relationship of 1.5 > f / fn. Description of the preferred embodiments of the present invention and with reference to the accompanying drawings, the above-mentioned objects and advantages of the present invention will become more apparent: This paper size applies the Zhongguan Standard (CNS) A4 specification ⑵Q χ as the public fn ϋ · I n I nn I «II ϋ I ϋ II II II ϋ n ϋ ϋ — ϋ ϋ n ϋ n ϋ ϋ nnn ϋ (Please read the precautions on the back before filling out this page) 476947 A7 、 Invention description (^) [Details of the invention] < Embodiment 1 > A first preferred embodiment of a kind of optical pickup according to the present invention is shown in Fig. 4. * The test si 4 'Q 4 is positioned directly opposite-the medium flat (light jujube) 1 〇〇 An optical lens at the end of the optical axis of 〇1. — Again, 4 glass plates 1 〇 07 ′-Beamsplitter! 〇2 和 —The alignment lens η is arranged on this objective lens! 〇 丄 and this light source 丄 〇 4. The alignment lens 103 includes a focusing lens i 0 3 a having a focusing magnification and a astigmatic lens 1 0 3 b having a diverging magnification. ', ... a phase detector 106 is arranged at the end of the light path of the light beam reflected from the beam splitter 10, and a focusing lens 105 is used to focus the reflected light beam, which is positioned Between the beam splitter 丄 02 and this phase splitter ^ 6. σ When the light source 104 emits laser light of 500 nm or less, the alignment lens has corresponding optical characteristics, which forms a special desire of the present invention. The total focal length of this alignment lens is 0.3, and the focal length of yyb is ". This alignment lens 103 conforms to -1-) > i / fn. ≪ Example 2 > The second embodiment of this kind of optical pickup is shown in the figure (Light Zen; two n light sources 104 are positioned coaxially to the facing-media (first industry) 1 () 〇-connecting the objective lens 101 Optical axis. Furnace 〇3, a λ / 4 glass-filled plate 〇7 and-Spectroscopy 9 through, see this between the objective lens 1 0 1 and the light source 104. The non-column is aligned with the lens 1 〇3 ( Please read the notes on the back before filling out this page}, ¾

Order --------- Line J Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs [Paper size applicable to Chinese Standard (CNS) A4 297, L, Description of Invention (§) Focusing lens 1033 and -has «= ^^ 2 of the divergence," the reflected light beam reflected by the beam splitter 102 is used by the collection lens 10 5 to collect between 6. /, is located in the beam splitter 10 2 and the phase detector 1 〇 田 This light source 1 〇4 emits -5GG nm or shorter. • Emissions =, this alignment Wei has a long optical hybrid, its brightness = = the total focal length of the quasi lens 103 is f, and this J through The focal length of 10 3 b is fn ', and this alignment lens 10 is in accordance with the relationship — 1.5> f / fn 〇 The difference between this embodiment and the first embodiment lies in the position of the alignment lens. The design information of the example 'optical structure will be displayed. The first two actual alignment lenses may have the same optical characteristics as the alignment lenses of the following embodiments. ≪ Example 3 > A third embodiment of the optical device is schematically shown in Fig. 6 'and the optical data of the optical pickup used for this unit 6 are listed in Table 1. Table 1 Surface curvature Diameter ~~ ——-- thickness glass name object surface infinite 0.100000 si infinite 6.200000 BK7 476947 Α7Β7 printed by the Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs 5. Description of invention (7) s2 infinite 3.000000 s3 -15.219848 1.000000 FDS1 s4 5.866928 2.000000 TAC8 s5 -4.118685 5.000000 s6 STOP 1.770182 1.802215 BACD5 K: -0.721945 A: 0.537259E-02 B: 0.183575E-03 C: 0.85500E-04 D:-. 121341E-04 s7 -179.717593 1.272566 K: -179.717593 A: 0.222258E-02 B:-. 194835E-03 C:-. 172951E-04 D: 0.399488E-05 s8 infinite 0.600000, CG 丨 s9 infinite 0.00. The image surface is infinite 0.00. 〇〇〇〇 The equation of the spherical surface (see the following equation (2)) Refractive index / the number of Abbe on the d line, v BACD5: 1.606048 / 61.3 FDS1: 2.012371 / 20.9 TAC8: 1.752798 / 54.7 BK7: 1.530849 / 64.2 'CG ，: 1.623343 / 31.0 The diameter of the entrance hole (mm) 4.0 Wavelength (nm) 400 (Please read the precautions on the back before filling this page) ·-Line. This paper size applies to China National Standard (CNS) A4 specifications (210 X 297 mm) Printed by the Employees ’Cooperative of the Ministry of Economic Affairs and Intellectual Property of the Ministry of Economic Affairs 476947 A7 V. Description of the invention (β) The divergence of this alignment lens and the focal length of the focusing element-4.085 / 3.517 (mm) The focal length of the entire alignment lens (mm) 10.0 Focal length (mm) 2.677 Σ1 / (/ ϊ · νί) -0.0004 In this embodiment, a light source of 400 nm, an alignment lens with a focal length of mm, and an objective lens with a diameter of 0.75 are used . The aberrations in this pickup are shown in FIG. 7. < Embodiment 4 > A fourth embodiment of such an optical pickup according to the present invention is schematically shown in FIG. 8, and optical data for the optical pickup of this FIG. 8 are listed in Table 2 in. Table 2 Surface Curvature Radius Thickness Glass Name Object Surface Infinite 3.680296 si Infinite 6.250000 BK7 s2 Infinite 3.000000 s3 -7.765552 1.000000 FDS1 s4 5.998733 2.000000 NBFD12 s5 -4.527848 5.000000. S6 1.770182 1.802215 BACD5 This paper is in accordance with Chinese national standards (CNS) A4 size (210 X 297 mm), ϋ ϋ ϋ · ϋ ϋ β-ϋ · ϋ 口, IIII ΜΜ II ϋ ί n l_i Ban 1 -ϋ n ϋ I ϋ n ϋ n ϋ ϋ n- (Please read the back first (Notes on this page) 476947 A7B7 V. Description of the invention (丨 丨) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs STOP K > 0.721945 A: 0.537259E-02 B: 0.183575E-03 C: 0.85500E-04 D :-. 121341E-04 s7 -11.452471 1.272566 K: -179.717593 Α: 0 · 222258E-02 B: 'D: 0.399488E-05 • 194835E-03 C:' 172951E-04 s8 infinite 0.600000 'CG- s9 infinite 〇〇〇〇〇〇〇〇 Infinite image surface 0.0000 Sphere equation (see equation (2) below) Refractive index / Number of Abbe on the d line, ν BACD5: 1.606048 / 61.3 FDSl: 2.012371 / 20.9 NAFD12: 1.834057 / 42.3 BK7: 1.530849 / 64.2 ^ 0 ^ 1.623343 / 31.0 diameter of the entrance hole (mm) 4.0 wavelength (nm) 400 divergence of the alignment lens and focal length of the focusing element (mm) -3.225 / 3.386 entire alignment lens Focal length (mm) 10.0 Focal length (mm) of the objective lens 2.677 (Please read the precautions on the back before filling this page)-%

Order --------- Line J This paper size is applicable to China National Standard (CNS) A4 specification (210 X 297 mm) 476947 Printed by A7 B7, Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs 5. Description of the invention (θ )

Zl / (fi * v0-0.0017 In this embodiment, a light source at 400 nm, an alignment lens with a focal length of 15 mm, and an objective lens with a diameter of 0.75 are used. The light is picked up here The aberrations in the filter are shown in Fig. 9. < Embodiment 5 > A fifth embodiment of such an optical pickup according to the present invention is schematically shown in Fig. 10 and is used for the pickup of Fig. 10. The optical data of the optical device are listed in Table 3. Table 3 Surface curvature radius thickness Glass name Object surface infinite 13.381632 si infinite 6.200000 BK7 s2 infinite 3.000000 s3 21.6695568 2.000000 BACD5 s4 -7.653445 1.000000 s5 -36.568237 1.000000 FD4 s6 3.690184 2.000000 BACD5 s7 -49.729832 5.000000 s8 STOP 1.770182 1.802215 BACD5 K > 0.721945 A: 0.537259E-02 B: 0.183575E-03 C: 0.85500E-04 D:-. 121341E-04 s9 -11.452471 1.272566 This paper is applicable to Chinese national standards (CNS) A4 specification (210 X 297 mm) -------- Order -------- II (Please read the precautions on the back before filling this page) 476947 A7 B7 Invention Description (/ 3) Employees of Intellectual Property Bureau, Ministry of Economic Affairs Printed by Fei Cooperative K: -179.717593 A: 0.222258E-02 B:-. D: 0.399488E-05 194835E-03 C:-. 172951E-04 slO Infinity 0.600000 'CG1 s9 Infinity 0.000.00.00 〇The image surface is infinitely large. The equation of the spherical surface (see equation (2) below) Refractive index / the number of Abbe on the d line, v BACD5: 1.606048 / 61.3 FD4: 1.808613 / 27.5 BK7 : 1.530849 / 64.2, CG ': 1.623343 / 31.0 diameter of the entrance hole (mm) 4.0 wavelength (nm) 400 divergence of the alignment lens and focal length of the focusing element (mm) 9.579 / -4.100 / 5.750 focal length of the entire alignment lens ( mrn) 20.0 Focal length of the objective lens (mm) 2.677 ΣΙ / Qi > /) 0.0018 An alignment lens with a focal length and an objective lens with a diameter of 0.75 are used. The aberrations in this pickup are shown in FIG. 11. An equation for a spherical surface, which was previously used in Forms 1 to 3. The paper size applies the Chinese National Standard (CNS) A4 (210 X 297 public love) (Please read the precautions on the back before filling this page).% Order --------- Line 476947 A7 Description of Invention (丨 ^) Mention 'Ch2 is printed by equation (2) Ch2 Printed by the Consumers ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs ^^ r'Ah' + BhSChS + Dh ^ El ^ + Fh14 ····· (2), where z is the depth from the surface, h is the distance from the optical axis, c is the curvature, k is a conic curve parameter, and A, b , C and spherical curve parameters. For the implementation examples 3'4 and 5, because the wavelength of the light beam emitted from this light source is within the error range of ± 10 °, this defocus angle can be expressed as ± 0.36 in the depth of focus. Uncertainty. FIG. 12 illustrates the optical path 'of an optical pickup using a conventional alignment lens and FIG. 13 illustrates aberrations in this conventional optical pickup of FIG. Relative to the ground 'FIG. 14 depicts the light path using an optical pickup of one of the alignment lenses according to the present invention, and FIG. 5 depicts the aberration σ in this optical pickup of FIG. 4. As shown in Figures 12 and 13, because this traditional alignment is designed to make it suitable for a wavelength of 500 legs or longer, the fragmentation magnification is not sufficient to correct a beam with a wavelength shorter than 500 nm Profit = chromatic aberration. For the optical pickup of Fig. I 2, the focal length of each lens is-^ Qin Wei and Gang, respectively, and the number of Abbe is 43.0 53.9 and 62.3, respectively, and 2 1 / (/ 丨 "丨) = 〇 〇〇67. As shown in Figure 13 '400 nm beam aberration is possible for this pickup, please, slightly' but for 405 nm 'the angle of this aberration suddenly increases. Therefore, this tradition Alignment lenses cannot be used for short-wavelength beams. 'At the same time, as shown in Figures 14 and 15, the change in the angle of aberration is smaller between 400 nm and 405 nm emission beams. The Zhang scale is applicable to China National Standard (CNS) A4 specifications (210 X 297 public love (please read the precautions on the back before filling this page) ------- Order --------- Line | • Γ

(Please read the precautions on the back before filling this page) Order --------- Line J Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 47⑽4 / A7 ------------ -------- V. Explanation of the invention (丨 /) The alignment lens of this Meming has a high focusing magnification, and the aberration can be effectively corrected. As a result, a light spot can be focused on the medium within a range corresponding to the change in the wavelength of the emitted light beam-the depth of focus. For the effective reduction of chromatic aberrations in such short-wavelength beams, the focal length of the entire alignment lens is f and the focal length of this astigmatic lens is fn. This alignment lens conforms to the relationship—15> f / fn is necessary . Preferably, it is assumed that the front focal length of the lens group (which constitutes the optical pickup) is f 1 f2 ··, and fn, which are arranged from the light source toward the medium, and d for the optical object f of the lens group _ The number of A bbe on the line is v: l 'v2' ···, and vn. This pickup conforms to the relationship—〇〇〇5 < i / (fi · vl) + 1 / (Ω · v2) +… + 1 / (fn · vn) < 0.00005. A light pickup H using two optical companies will be described in the following examples. < Embodiment 6 > Considering FIG. 16, a first light source 10a is positioned at the end of the optical axis of an objective lens 101 (which is directly opposite to the medium 1Qo). One of the apertures used to control the objective lens 101 is a wavelength-selective transition device 300, which is aligned with the lens 103 (which is a feature of the present invention), and a beam splitter 100 is arranged here. The objective lens χ 〇 丄 and this first light source 丄 04a. This beam splitter 102 transmits the laser beam emitted from the first light source 403, and reflects the laser beam emitted from the second light source 〇4 W. As shown in FIG. 16, the second light source module 0 4 b is arranged on the light path of the light beam reflected from this split to 102. The use of this wavelength selection filter 300 is arbitrary. In other words, this paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 public copy) 476947 A7 B7 V. Description of the invention (K), this wavelength is selected over the wire, 3 〇〇 在 # exists for phase control No. One and the first light source 1 04a and 1 104b caliber need a long day; are incorporated into this optical pickup. For example, if the first light source 1 〇 | emits a 400 nm blue laser and requires a caliber of 10.7, and the first and a source 1 0 4 b emits a 650 nm red laser and requires one 〇6 口 / 一 光 This wavelength selection device 3 0 Q is used to allow the aperture of the objective lens to be reduced to 0.6 for the Congdi laser beam when transmitting all = nm laser beams. Tian Yi's traditional beam emission / detection device, which includes an image detector and-Tian She 'polar body, may be used as the first and second light source workers 043 and 104b, so-laser beam Can be transmitted and received by the same device. The expanded 10 3 ′, which forms a feature of the present invention, is as described previously. The field lens includes a focusing lens 1 0 3 a and a astigmatic lens i 0 3 b with astigmatic magnification. Assume that the entire alignment lens is transmitted through the astigmatic lens 1 ◦ 3 b. The focal length of the astigmatism lens 1 is 3, and the pair of laser beams from the first source 10 4 a and 10 4 b will be synchronized to help correct it. Chromatic aberration. < Embodiment 7 > 1 ο 1 7 ′ A first light source 1 0 4 a is positioned on an objective lens so as to face i—media 1. Q) at the end of the optical axis. Wavelength selector 300 used to control the aperture of 101,-the first eight 2 03 (which is a feature of the present invention) and the second, second and second two-knife precursors 102a, 102m1〇2c Arranged here ^ Paper rule -------- ^ --------- (Please read the precautions on the back before filling out this page} Printed by the Employee Consumer Cooperative of the Ministry of Economic Affairs and Intellectual Property of the Ministry of Education 476947 A7 _ B7 V. Description of the invention (p) The objective lens 1 0 1 and the first light source 1 0 4 a are at a predetermined position. The third beam splitter 1 0 2 c transmits the light from the first light source 1 0 4 a. The laser beam 'and the laser beam from a first light source 1 Q 4 b are reflected toward the medium 100. As shown in FIG. 17, the second light source 1 0 4 b is arranged at the third beam splitter 1 〇2 c on the optical path of the light beam reflected. The second beam splitter 10 2 b transmits the laser light beams from the first and second light sources 丄 04a and 104b, and reflects the light beam reflected from the medium. , Which originates from this second light source 104b. The light beam reflected by this medium 1000 and steered by this second beam splitter 102b is directed by a second focusing lens 8202 Set to a second phase detector 7 〇. The first beam splitter 10 2 a transmits the laser beams from the first and second light 04 a and 104 b to the medium 丄 〇〇 Similarly, the first splitter 10 2 a reflects the light beam reflected from the medium X 〇〇, which originates from the first light source 104 A, and transmits the light beam reflected from the medium 1 0. The origin of the second light source i 〇4b. The light beam reflected by this medium 100 and turned by this first beam splitter i 〇2 a is collected by a first? Κ set lens 801 to a first phase debt The use of this wavelength selection filter 3 is optional. In other words, this wavelength selection filter 3 is used for the first and second light sources 1 for separate control. 〇4 a and 10 4 b are required to be incorporated into the optical pickup when required. For example, if the first light emits a laser and requires a port of 0.7 = = ^ I · ϋ nn I n ϋ I · MM w WW _ I-(Please read the notes on the back before filling this page)-

A7 V. Explanation of the invention () Source 1 0 4 b emits a 650nm red laser and requires a sentence of 10.6. The filter 3 0 0 is used to transmit all 400, please be protected by Tian She, allowing access. The aperture of the objective lens is reduced to 0.6 for a 65 ° beam. The two pairs of t-lenses 10 3 ′, which form a characteristic of the present invention, include the focusing lens with focus magnification, and the astigmatism lens with astigmatism 丄 03b. Assume that the entire alignment lens: θ 3 has a focal length of f ′ and this astigmatism lens 丄 Q 3 is aligned with the lens 1 〇 3 符 八 关 # 1 ′,,, and is fn ′, which is Kenji / fn. The laser beams ′ from the first and second light sources i 〇 4 a and 丄 〇 4 b of the alignment lens 100 m and synchronously help them correct chromatic aberration. &Lt; Example 8 &gt; Line-ιοΠ] 18: A first light source 104a is positioned at the end of the optical axis of the objective lens G, facing the media 1QQ). Used to suppress the objective lens! The wavelength selection filter 3, which is one of the apertures, is: the second, third, and third beam splitters 102a, 102b, and 〇2c are arranged on the objective lens i 0 i and the first light source. Pre-placement between 4 and 3. Similarly, the '-alignment lens i Q 3 (which is a "feature" of the present invention) is positioned between the first and second beam splitters. The second beam splitter 10 2C transmits a laser beam &apos; from the first light source worker 04a and a laser beam from the second light source i 04b to the medium 100. As shown in Fig. I 8, this second light source 丄 〇4 b is arranged on the light beam reflected from the third beam splitter 丄 02 c. The paper size of this paper applies the Chinese National Standard (CNS) A4 specification (21G X 297). Public reply-476947 Printed by A7 B7, Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs 5. Description of the invention (On the light path. The second beam splitter 102b transmits the light from the first and second light source workers 04a and 104b. All the laser beams reflected by this medium originate from this second light source i 04b. The light beam reflected by this media worker 00 and steered by this first beam splitter 1 02b is first The two focusing lenses 8 0 2 are focused on a second phase detector 7 0 2. The first beam splitter 1 0 2 a transmits all the laser beams from the first and second light sources 10 4 a and 104 b. To the medium 100. Similarly, the first splitter 10 2a reflects the light beam reflected from the medium i 00, which originates from the second light source 104, and the transmission is reflected from the medium 100 The light beam originates from this second light source i 04. It is reflected by the medium 100 The light beam turned by this first beam splitter 10 2 a is focused by a first focusing lens 8 0 1 to a first phase detection 0 2 °-the selection of this wavelength selection filter 3 Q 0 is arbitrary. Say ' This wavelength selection filter, 300, is incorporated into this pickup when it exists for separately controlling the apertures of the first and second light sources 10 "and 104b, which are required by Japan. For example, In other words, if this first-light source: emits a 40nm blue laser and requires a caliber of 107, = this μ a = source 1 0 4 b emits a 050 nm red laser and needs-brother-light. 乂The wavelength selection filter 300 is used to allow the aperture of the objective lens to be reduced to 0.6 nm when all the two laser beams of the transmission wheel are passed. 103, which forms a feature of the present invention, such as the previous I paper size applicable to the Chinese National Standard (CNS) A4 specification ⑵Q χ 297 public love "-------- order --------- line» ( (Please read the precautions on the back before filling this page) 476947 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 -------- BL________ V. Invention Description 0 ) The description 'includes a focusing lens 1 0 3 a with focusing magnification and a astigmatic lens 1 0 3 b with diverging magnification. It is assumed that the focal length of the entire alignment lens 1 0 3 is f' and this astigmatic lens 1 〇 3 The focal length of b is fn, and this alignment lens 1 03 conforms to the relationship 1.5 &gt; f / fn. This alignment lens 1 03 is aimed at the thunder from the first and second light sources i04a and i04b. The light beam is emitted and synchronously helps it correct chromatic aberration. &lt; Embodiment 9 &gt; Consider Fig. 19, a first light source 104a is positioned at the end of the optical axis of an objective lens 101 (which is directly opposite a medium 100). One wavelength selection filter 300, which is used to control the aperture of the objective lens 101, and the first, second, and third beam splitters, 102 and 102 are arranged on the objective lens 10. 1 at a predetermined position between this and the first light source 104a. Similarly, an alignment lens 丄 03 (which is a feature of the present invention) is positioned between the second and third beam splitters 丄 2121 and 〇2 C. The second beam splitter 10 2C transmits a laser beam from the first light source 104a, and reflects the laser beam from the second light source 104a toward the medium 100. As shown in Fig. 19, the second light source 丄 04b is arranged on the light path of the light beam reflected from the third beam splitter 102c. The second beam splitter 10b transmits all the laser beams from the first and second light sources 0a and 104b, and reflects the light beams reflected from the medium, which is from the second light source 0b. The origin. The light beam reflected by this media 丄 0 0 and steered by this second beam splitter 丄 〇2 b is adapted to a Chinese paper standard (CNS) A4 (210 X 297) by a paper size ----- ^ --------- ^ 1 ^ (Please read the precautions on the back before filling out this page) H ϋ ϋ ϋ 476947 Printed by the Consumers ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 V. Invention Description (&gt; \) The second focusing lens 802 is focused on a second phase detector 702. The first beam splitter 10 2 a transmits all the laser beams from the first and second light sources 104 a and 104 b to the medium 100. Similarly, the first splitter 102a reflects the light beam reflected from the medium 100, which originates from the second light source 104a, and transmits the light beam reflected from the medium 100, which is from the first Origin of the two light sources 104b. The light beam reflected by the medium 100 and turned by the first beam splitter ^ 〇 2 a is collected by a first focusing lens 80 丄 onto a first phase detector 602. The use of this wavelength selection filter 300 is arbitrary. In other words, this, the long selection filter 300 is incorporated into this pickup when there is a need to separately control the apertures for the first and second light sources 1043 and 104b. Device. For example, if this first light source 〇 04 a emits a 400 nm blue laser and requires a calibre of 10.7, and 'this second light source 10 4 b emits a 650 nm red laser and requires In the mouth of 10.6, this wavelength selection filter 300 is used to allow the aperture of the objective lens to be reduced to 0.6 for the beam when all the = beams of the transmission wheel. ^ nm field-aligning this alignment lens 103, which forms the description of the present invention, includes a focusing lens i with a focusing power i, an astigmatism lens 1 (3 3 b with all divergent powers). f, and this astigmatism lens] 〇3 b's wide brother 1 aligning lens i〇3 ^ _- 15> f / fnm4fm (Please read the precautions on the back before filling in this page)-Line · 3 alignment from the first -And the second light source 1043 and 104. === _ The scale is applicable 297 Gong Ding 476947 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7_ 5. Description of the invention (&gt; &gt;) light beam, and synchronously Correction of chromatic aberration. <Embodiment 10> An tenth embodiment of the optical pickup according to the present invention is schematically shown in Figs. 20 and 22, and is used in the optical pickup of Figs. 20 and 22. The optical data are listed in Table 4. Table 4 Surface curvature radius Thickness Glass name Object surface Infinity 0.100000 si Infinity 0.20000 BK7 s2 Infinity 5.929508z 2.122789z s3 Infinity 6.0000 BK71 s4 Infinity 3.000000 s5 -4.081133 1.000000 FDS1 s6 30.164147 2.000000 BACD5 s7 -3.467121 5. 000000 K: -0.2007701 A: 0.445555E-03 B: -0.119205E-03 C: 0.316310E-04 D:-. 267022E-05 s8 STOP 1.770182 1.802215 BACD5 K: -0.721945 A: 0.537259E-02 B: 0.183575E -03 C: 0.855000E-04 D:-. 121341E-04 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page)

Order --------- line J 476947 A7 B7 V. Description of invention (〉〉) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs s9 -11.452471 1.272566 K: -179.717593 A: 0.222258E-02 B:- .194835E-03 C:-. 172951E-04 D: 0.399488E-05 slO Infinite 0.600000, CG, s9 Infinite 0.000.00.00 The surface of the image is Infinite. 0.0000.00 Equation (see equation ⑵ above) Refractive index / number of Abbes on the d-line, v BK7: 1.514520 at 650 nm / l.530849 at 400 nm / 64.2 FDS1: 1. 911294 at 650 nm / 2.012371 at 400 nm / 20.9 TAC8: 1.725425 at 650 nm / 1.752798 at 400 nm / 54.7 BACD5: 1.586422 at 650 nm / 1. 606048 at 400 nm / 61.3 'CG': 1.581922 at 650 nm / 1. 623343 at 400 nm / 31.0 diameter of the hole (Nun) 4.0 Wavelength (nm) 400,650 (Please read the precautions on the back before filling this page)

Order --------- Line J This paper size is applicable to China National Standard (CNS) A4 specification (210 X 297 mm) 476947 A7 V. Description of the invention Divergence of the alignment lens-3.499 / 4.239 at 400 nm ( mm) Focal length of the entire alignment lens 19.995 at 400 nm Focal length of the objective lens (πιπ〇ΣίΤαΓΤο ~~ '' Ρ 1-&quot; &quot; '----- 2.677 at 400 nm -0.0032 Employees of Intellectual Property Bureau, Ministry of Economic Affairs Cooperative print— * wv / u η ”V 丄 iJULii, one of the focal lengths of the alignment lens, and an objective lens with a diameter of 0.75 is used, because the wavelength of the light beam emitted from this light source is in the soil Within an error range of 5 nm, this defocused angle can be expressed as an uncertainty of 0.36 // m in terms of focal depth. Similarly, the optical distance in nm is 0.012 λ 〇 Figure 2 0 is described in In the optical pickup according to the present invention, the optical path of a light beam having a wavelength of 4.05 nm, and the aberration in FIG. 2 described in the optical pickup of FIG. 20 are described in FIG. In the optical pickup, the optical path of a light beam having a wavelength of 605 nm, and FIG. 2 3 is described in FIG. 2 2 Aberrations in the lens. In particular, FIG. 24 is a comparative description of the aberrations of the 400 nm beam and the 401 and 405 1101 beams in the optical pickup of FIG. 20. As shown in FIG. 24 The difference between the image of the 400 nm beam and the 405 nm beam can hardly be detected in the optical pickup according to the present invention. Because the alignment lens according to the present invention has a high focusing magnification, the aberration can be effectively Correction. As a result, a light spot can be focused on a medium within the range of the focal depth corresponding to the change in the wavelength of the emitted beam. For more effective paper on chromatic aberrations with respect to such short wavelength beams Standards are applicable to China National Standard (CNS) A4 specifications ⑽ X 297 public y (please read the precautions on the back before filling out this page)%. --Line-476947 A7 V. Description of invention (&gt; &lt;) Decrease, assuming this The focal length of the entire alignment lens is f, and the focal length of this astigmatism lens is fn. It is necessary that the alignment lens conforms to the relationship of 0.5> f / fn. Preferably, it is assumed that the lens group (which constitutes the optical pickup) The front focal length is fl, f2 '..., and fn, which are determined from this light source Aligned to this medium, and the number of A bbe on the d — line of the optical substance of the lens group is vl, V2, ..., and vn, and this optical pickup conforms to the relationship _0055 &lt; 1 / (fl · vl) + · v2) H ----- l·l / (fn · vn) &lt; 0 · ⑻05. The optical pickup according to the present invention is compatible with both today's DVDs and HD-D VD s. It requires a blue light source near 405 nm and an objective lens with a diameter of 0.6, but this specification has not been standardized. According to the optical pickup of the present invention, an objective lens having a high aperture and a light source having a short wavelength of 500 nm or less are used to ensure the reading and recording of high-density information. In particular, the alignment lens having this configuration explains the above-mentioned advantage, the reading and recording of density information, by effectively correcting the chromatic aberration related to the = long blue laser beam. When the present invention has been specifically described with reference to its preferred embodiments, with these techniques: can be achieved: Ϊ; not =: = = == meaning of the spirit and scope of the present invention. Specifications (210 x 297 public love) 476947 Α7 Β7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 5. Description of the invention (&gt;) [Early description of the pattern] Figure 1 shows a picture about a laser In terms of the output magnification of the polar body under different temperature conditions, the change of the emission wavelength of this laser-polar body; Figure 2 is a graph showing the change of the refractive index with respect to the wavelength of various optical substances; Figure 3 is a A schematic view of a conventional objective lens for chromatic aberration correction; FIG. 4 shows an optical arrangement of a first embodiment of an optical pickup according to the present invention; FIG. 5 shows a second optical pickup according to the present invention. Optical arrangement of the embodiment; Fig. 6 shows a light path of a third embodiment of the optical pickup according to the present invention; Fig. 7 illustrates aberrations in the optical pickup of Fig. 6; A light path of a fourth embodiment of the optical pickup; FIG. 9 illustrates aberrations in the light pickup of FIG. 8; FIG. 10 shows a light path of a fourth embodiment of the optical pickup according to the present invention; 11 describes aberrations in the optical pickup of FIG. 10; 12 depicts the light path of an optical pickup using one of the conventional alignment lenses; FIG. 13 depicts the aberrations in the conventional optical pickup of FIG. 12; FIG. 14 depicts an optical pickup using an alignment lens according to the present invention (Please read the precautions on the back before filling out this page) ¾ IT, ··················· This paper size applies to China National Standard (CNS) A4 specifications (210 X 297 public love) FIG. 15 illustrates the light path of the invention; FIG. 15 depicts the aberrations in the optical pickup of FIG. 14; FIG. 16 shows an optical arrangement of a sixth embodiment of an optical pickup according to the present invention; An optical arrangement of a seventh embodiment of an optical pickup according to the present invention is shown; FIG. 18 shows an optical arrangement of an eighth embodiment of an optical pickup according to the present invention; FIG. 19 shows an optical arrangement according to the present invention Optical arrangement of a ninth embodiment of an optical device; Fig. 20 depicts the optical path of a light beam with a wavelength of 々os nm in an optical pickup according to the invention; Fig. 21 depicts the optical pickup in Fig. 20 Aberrations; Figure 2 2 depicts the The optical path of a light beam with a wavelength of 65 nm in the optical pickup; FIG. 23 depicts the aberrations in the optical pickup of FIG. 22; and FIG. 24 describes the aberration in the optical pickup of FIG. 400 nm beam and aberration for 401 and 405 nm beams. [Reference Table] 10 0 Media (Disc) 101 Receiver 10 2 Beamsplitter 102a First Beamsplitter 1 0 2 b Second Beamsplitter Applicable to this paper size China National Standard (CNS) A4 Specification (210 X 297 Public Love) (Please read the precautions on the back before filling this page) Order --------- ί 476947 A7 _ B7 V. Description of the Invention (&gt;?) 1 ◦ 2 C Third beam splitter 1 0 3 Alignment lens 1 0 3 a Focusing lens 1 0 3 b Astigmatic lens 1 0 4 Light source 1 0 4 a First light source 1 0 4 b Second light source 1 0 5 Focusing lens 1 0 6-phase detector 1 0 7/4 glass plate 3 0 0 Wavelength selection filter 6 0 2 First-phase detector 7 0 2 Second-phase detector 8 0 1 First alignment lens 8 0 2 Second alignment lens (Please read the precautions on the back before filling this page)

Order --------- Line J Printed by the Employees' Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)

Claims (1)

476947 6. Patent application scope 1. An optical pickup includes: a light source 'for generating a laser beam of 500 nm or less; an objective lens' for focusing the laser beam onto a medium; a phase Detected as, 'used to convert the laser beam reflected from this disc into an electronic signal; and-alignment lens' which is arranged between this wire and the objective lens, including-a astigmatic lens with a divergent magnification and a A focusing lens having a focusing magnification, in which the total focal length of this alignment lens is assumed to be f, and the focal length of this astigmatic lens is fn '. This alignment lens conforms to the relationship _15> f / fn. 2. If the optical pickup of item i of the patent application scope, further includes a beam splitter between the objective lens and the phase side device, which is used to direct the laser beam from the light source through the objective lens to the The medium, and reflects the laser beam reflected from the medium. 3. If the optical pickup of item 1 or item 2 of the scope of patent application is applied, further includes a focusing lens between the phase detector and the beam splitter, which is used to reflect the light emitted from the medium. The beam of light made this handsome guy cry. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 4. If the optical pickup of item 2 of the patent application scope, the lens is arranged between the beam splitter and the light source. ^ 5. For the wire pickup of item 3 of the patent application, the alignment lens is arranged between the beam splitter and the light source. No 6. As for the thread pick-up of item 2 of the patent application scope, is arranged between this leaking mirror and the split wire. Material 1 Brother 7. If the optical pickup of item 3 of the patent application scope, in which the lens is aligned with the wood paper standard Gu Zhongguan Jiaxian (CNS) A4 Regulation & ^ — — 476947 8888 ABCD VI, The scope of patent application is arranged between this objective lens and the beam splitter. 8. If the scope of the patent application is No. 1, No. 2, No. 5 to No. 7, the light pickup is, where the front focal length of the lens group from this light source toward this optical disc is fl respectively. , Β, ..., and fn, and the number of A bbe of the optical objects of this lens group are v 1, v2, ..., and vn, respectively, and this optical pickup conforms to the relationship—00005 &lt; 1 / (fl · Νΐ) + ι / (β · V2) + ... + 1 / (fn · vn) &lt; 0.00005. 9. An optical pickup includes: a medium (please read the notes on the back first and then ^ this page) a first and a second light source, which respectively correspond to the first and the second to generate laser beams of different wavelengths ; An objective lens is used to focus the laser beams from the first and second light sources on the first and second media respectively; the first and second phase detectors are used to separately Receive the laser beams emitted from this first and -line · second light source and reflected from this first and second media; and the printed clothing of the consumer cooperative of the staff of the Intellectual Property Bureau of the Ministry of Economic Affairs ... an alignment lens, which is arranged In the light path of a laser beam with a relatively short wavelength, the alignment lens includes-a astigmatic lens with a divergent magnification and-a focusing lens with a focusing magnification. The total focal length is f, and the focal length of this astigmatism lens is fn. This alignment lens conforms to the relationship. Wavelength selective filtering cry. 7 Shen = the optical pickup of the 9th item of the scope of interest, ^ in this 4_ radiation-with a laser beam of about _ nm-wavelength, and this second paper rule i applies the Chinese National Standard (CNS) A4 specification XQ x 297 has loved 4 / () 947 A8 B8 C8 D8 6. The patent application scope The light source emits a laser beam with a wavelength of about 650 nm. 12. The optical pickup of any one of the tenth or eleventh scope of the patent application, wherein the first light source emits a laser beam having a wavelength of about 400 nm 'and the second light source emits a light beam having A laser beam with a wavelength of about 650 nm. U • If the optical pickup of any one of items 9 to 11 of the scope of patent application, if the front focal length of the lens group in which the light source faces the optical disc is Π, β, ..., and fn, and the number of bbe of the optical substance of this lens group are v 1, v 2,..., and v n respectively, and this pickup conforms to the relationship—0 · 005 &lt; l / (fl · vl) + l / (f2 · V2) + ... (fn · νη) &lt; 0.005. 14. If the optical pickup of item 12 of the scope of patent application, in which if the front focal length of the lens group from this light source toward the optical disc is fl, β, ..., and fn, respectively, and the abbe of the optical substance of this lens group The numbers are vl (please read the notes on the back first and then on this page). _ Member of the Intellectual Property Bureau of the Ministry of Economic Affairs and Consumer Cooperatives printed v2, ..., and vn. ; 1 // (fi vl) + l / (f2 · v2) h ----- l / (fn · vn) &lt; 0.0005. _A kind of optical pickup includes: an objective lens 'which is arranged facing the first and second media; a first light source which is arranged on the light path of the objective lens; a beam splitter which is' which is arranged here Between the objective lens and the first light source; a second light source arranged on the light path of the light beam reflected from the beam splitter; a first phase detector for receiving the light beam emitted from the first light source, and The light beam reflected from this first medium; Guan Jia Standard (CNS) A4 specification (210 X 297 mm) 15.-line · 476947 Patent application scope a second phase detector for receiving the light emitted from this second light source The light beam 'and the light beam reflected from the second medium; an alignment lens arranged between the objective lens and the beam splitter; the alignment lens includes a astigmatic lens having a divergent magnification, and a lens having a focusing magnification Focusing lens, where the total focal length of this alignment lens is assumed to be f, and the focal length of this astigmatic lens is allowed, this alignment lens conforms to the relationship -1.5 &gt; f / fn. The optical pickup of the Shishen-Mon patent scope 项 I5, further includes an H-wavelength lion filter for the objective lens and the alignment lens, which is used to control the aperture of the objective lens. 17: The optical pickup of item 15 or item 16 of the Rushen patent, in which the first light source emits a laser beam having a wavelength of about 400 nm, and the second wire emits-having a wavelength of about 650 mm ―Laser beam of wavelength. 18 · As for the optical pickup of the 15th or 16th in the scope of patent application, in which if the light source is directed toward the lens of the optical disc, the front focal length is respectively, β, ... and fn, and The number of A bbe of the optical substance is Vl 'V2' ..., and vn respectively, and this optical pickup conforms to a relationship of 0.005 &lt; ι / (π · νΐ) + ικ (ί2.ν2) + ... + 1 / 0.0005. 19. If you apply for wire picking for item 17 of the full-time job, if the front focal length of the lens group from this light source toward the optical disc is η, β, ..., and fn ', and A of the optical substance of this lens group, The number of bbe is vl, v2 ', and vn, respectively. This pickup conforms to the relationship _〇〇〇05 &lt; 丨 / ⑺ g paper size applies Chinese National Standard (CNS) A4 specifications ⑵〇x 297 public love (please Please read the precautions on the back, and then this page.) Assembly-line-Printed by ASB8 C8 D8, Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 6. Application scope • vl) + i / (f2 · v2) + ~ + 1 / ( fn · vn) &lt; 0.00005. 20 · —An optical pickup includes: an objective lens arranged to face the first and second media; a first light source arranged on a light path of the objective lens to emit a light to the first medium; Laser beam; first, second and third beam splitters arranged at a predetermined position from the first light source toward the objective lens; p-a second light source arranged to be reflected by the first beam splitter In the light path of the beam, it is used to emit a laser beam to the second medium through the first beam splitting action; p a first phase detector, which is arranged to be reflected by the third beam splitter. On the light path of the light beam, it is used to receive the laser beam emitted from the first light source and the laser beam reflected from the first medium; p-the second phase detector, which is arranged by the second beam splitter The light path of the reflected beam is used to receive the laser beam emitted from the second system. And; ^ the laser beam reflected by this first medium; and the consumer cooperative of the Intellectual Property Bureau of the Ministry of Economy printed an alignment lens' which is arranged between this second and third beam splitters, this alignment lens includes A astigmatic lens with divergent magnification, and a focusing lens with eighteen focusing magnifications. In this case, the focal length of the lens is f, and the focal length of the astigmatism transmission is fn. f / fn. In 1 ^, please turn over the 2G wire, and further include a “wavelength selective filter” between the alignment lenses, which is used to control the aperture of the objective lens. 297 mm) 22j ° The optical pickup of the 20th or 21st patent application, in which the first light source emits a laser beam having a wavelength of about 400 nm 'and the second light source emits a light beam having a wavelength of about 650 nm. Laser beam of wavelength. 23. If the optical pickup of the 20th or 21st scope of the patent application, if the front focal length of the lens group of the light source facing the optical disc is fl, β, ..., and fn, respectively, and this lens group The number of Abs of the optical substance is vl, V2, ..., and vn, respectively, and this optical pickup conforms to the relationship-〇〇〇5 &lt; ^ / (fl ^ vl) + I /. V2) + ... + l / (fn · Vn) &lt; 0.0005 〇 The optical pickup of item 22 of Rushen # patent, in which if the front focal length from the light source toward the lens group of the optical disc is fl, β, ..., and fn, and the number of abbe of the optical substance of this lens group are W'v2 '..., and vn respectively, and this optical pickup conforms to the relationship—00〇5 &lt; 1 / (fl • vl) + l / (f2 · v2) &gt;] ----- l · l / (fn · vn) &lt; 0.0005. 25 · —An optical pickup includes: an objective lens arranged to face the first and second media; a first light source arranged on the light path of the objective lens to emit a light to the first medium; Laser beam; first, second and third beam splitters arranged at a predetermined position from the first light source toward the objective lens; a second light source 'which is arranged at a position reflected by the first beam splitter On the light path of the beam, it is used to emit a laser beam to the second medium through the first beam splitter; the paper size is suitable for home standards (0 milk from 4 'grid (21 ()) &lt; 297 Gongai) ----- &quot; (Please read the notes on the back first, then this page) Ordering _ Printed by the Consumers' Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs to apply for a patent scope P — the first phase detector, which is arranged On the light path of the beam reflected by the third beam splitter, it is used to receive the laser beam 'emitted from the first light source and the laser beam reflected from the first medium; the second phase detector, which is Align the light paths of the light beams reflected by this second beam splitter, To receive a laser beam emitted from the second light source and a laser beam reflected from the second medium; and an alignment lens arranged between the objective lens and the third beam splitter, the alignment lens Including a astigmatic lens with a divergent magnification and a focusing lens with a focusing magnification, in which the total focal length of the alignment lens is assumed to be f, and the focal length of the astigmatic lens is fn, the alignment lens conforms to a relationship of 1.5 &gt; f / fn. 26. If the optical pickup of item 25 of the scope of patent application is applied, further including the objective lens and the fresh lens _-wavelength lizard device, the diameter of the objective lens is controlled by the wire. -27. The optical pickup of the 25th or %% of the scope of application for a patent, where = = light source emission-a laser beam having a wavelength of approximately · nm, and this second light source emits a light beam having approximately 65 η Laser beam. Agricultural 28, such as the optical pickup of the 25th or the %% of the scope of patent application, in which, for example, the front focal length of the lens group from this light source toward this handle is respectively ^, 2 '... The number of eight optical elements of the lens group is vl, v2, ..., respectively, which is lL. ^. 1Λ and ... 'This optical pickup conforms to the relationship of 0.005 &lt; 1 / (Π.ν1) + 1κ ( β.ν2) + ... + ιχ 0.0005 ο… 476947 A8 B8 C8 D8 6. Application scope of patent 29. For example, the optical pickup of item 27 of the scope of patent application, in which if the light source is directed to the front of the lens group of the optical disc The focal lengths are fl, f2, ..., and fn, and the number of Abbe of the optical substance of this lens group is vl, v2, ..., and vn, respectively. This optical pickup conforms to the relationship of 0.005 &lt; l / (fl • vl) + l / (f2 · v2) H ----- hl / (fn · vn) &lt; 0.0005. (Please read the precautions on the back first, then this page) Order: _ Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)