WO2005088376A1

WO2005088376A1 - Beam shaping lens

Info

Publication number: WO2005088376A1
Application number: PCT/JP2005/004333
Authority: WO
Inventors: Norihisa Sakagami; Hiroyuki Takeuchi
Original assignee: Nalux Co., Ltd.
Priority date: 2004-03-12
Filing date: 2005-03-11
Publication date: 2005-09-22
Also published as: JPWO2005088376A1

Abstract

A beam shaping/focusing lens for shaping an incident beam for which the object numerical apertures in the X- and Y- directions are different from each other when the optical axis is made the Z-axis in order that the area where the ratio of the intensity of the focused beam at the cross section perpendicular to the direction in which the beam travels to the peak intensity is a predetermined value or above may be a true circle. The profiles of the incident and exit surfaces of the lens are expressed by [Eq. 16] (1) The coefficients of the terms can be determined independently. The coefficients are determined so as to satisfy |CX-CY|2×SR2×log10(BF)×CE×NAR4×FF<0.04 Where FF (mm) is the distance between the light source of the incident beam and the surface of the lens on the light source side, BF (mm) is the back focus of the lens, CE=|100-curclalrity| (%) is the error of the circularity which is the ratio of the diameter in the X-direction of the cross section to that in the Y-direction, NAR=NAX/NAY is the object numerical aperture, and SR(%) is the ratio of the designed peak intensity to the maximum side robe intensity.

Description

Specification

Beam shaping lens technology

The present invention relates to a lens having a beam shaping function and used for an optical pickup device, an optical coupler, and the like.

Background art

[0002] Edge-emitting type semiconductor lasers The emitted light beams have different spread angles in the vertical and horizontal directions with respect to the semiconductor laser layer. That is, the divergence angle in the vertical direction with respect to the semiconductor laser layer is larger than the divergence angle in the horizontal direction with respect to the semiconductor laser layer.

[0003] For example, in an optical pickup, when a light beam from a semiconductor laser light source is condensed as a light spot on an optical disc, the light spot has an elliptical shape. It is desirable that the shape of the light spot be a perfect circle. When the degree of the desired ellipse increases, the recording / reproducing function deteriorates.

[0004] In order to make the shape of the light spot close to a perfect circle, for example, it is conceivable to shield a part of the semiconductor laser layer in the vertical direction from light. In this method, the energy loss is large.

[0005] For this reason, beam shaping is performed to make the cross-sectional shape of the light beam of the semiconductor laser power close to a perfect circular shape. As a method of performing beam shaping with a single lens, a method of using an anamorphic 'lens that is rotationally asymmetric with respect to the optical axis is known (for example, Patent Documents 1 to 3 described later).

[0006] However, the conventional single lens that performs beam shaping does not have sufficient measures against so-called side lobes which are inevitably caused by making the cross-sectional shape of a light beam close to a perfect circle. For this reason, for example, in optical pickups such as Blu-ray, DVD, and CD, crosstalk may occur due to side lobes when reading data.

[0007] It should be noted that the power described in the optical pickup as an example and other fields are also semiconductor lasers. There is a need for beam shaping to make the cross-sectional shape of the light beam from the laser closer to a perfect circle. For example, in an optical coupler that couples light from a semiconductor laser to an optical fiber, there is a need for beam shaping to make the cross-sectional shape of the light beam from the semiconductor laser closer to a perfect circle in order to increase the coupling efficiency. . Further, the processing laser also has a similar dose. Further, the light source may be a light emitting diode or the like instead of a semiconductor laser. Patent Document 1: JP-A-2003-66325 (Paragraphs 39 and 56, FIG. 4 and others)

Patent Document 2: Japanese Patent Application Laid-Open No. 2002-208171 (Paragraph 60, FIGS. 2 and 3, etc.)

Patent Document 3: Japanese Patent Application Laid-Open No. 2000-292783 (10th paragraph, FIG. 1, etc.)

Disclosure of the invention

Problems to be solved by the invention

[0008] There is a need for a beam shaping lens that reduces the side lobe as much as possible while making the cross-sectional shape of the light flux close to a predetermined perfect circular shape.

[0009] The beam shaping lens of the present invention reduces crosstalk when reading data in optical pickups such as Blu-ray, DVD and CD.

[0010] The beam shaping lens of the present invention, when used in the collimator portion of an F-lens, improves black streaks accompanying charge generation on the photosensitive drum due to the influence of side lobes.

[0011] The beam shaping lens of the present invention improves the coupling efficiency of the optical coupler that couples the light of the semiconductor laser to the optical fiber.

The beam shaping lens of the present invention improves the finish of a processed surface in semiconductor laser processing.

Means for solving the problem

[0013] The beam shaping condenser lens according to the present invention has a structure in which, in the XYZ coordinate system, an incident beam having a different object numerical aperture in the X and Y directions with the Z axis as an optical axis, The beam is shaped so that a region where the intensity in a cross section perpendicular to the traveling direction is equal to or more than a predetermined ratio with respect to the peak intensity becomes a perfect circle. The profile of the entrance and exit sides of the lens includes a term representing the aspheric surface and multiple correction terms represented by fe (x, y) that satisfy fe (x, y) = fe (-x, y) formula [Equation 1] c _x x + c _y y

z

1 + Jl "-(1 + k _x ) (c _x ² x ² )-(1 + k _y ) {c _y ² y ² )

And the coefficients of each correction term can be determined independently of each other. The distance between the light source of the incident beam and the side of the lens light source is FF (mm), the back focus of the lens is BF (mm), and the circularity error is the ratio of the diameter of the cross section in the X direction to the diameter in the Y direction. To

CE = I 100-roundness I (%)

The object numerical aperture in the X direction is NAX, the object numerical aperture in the Y direction is NAY, and the object numerical aperture is

NAR = NAX / NAY

The ratio of the maximum sidelobe intensity to the designed peak intensity is SR (%),

ICCI ² X SR ² X log (BF) X CE X NAR ⁴ X FF <0.04

X Υ 10

The coefficient of the term representing the aspherical surface and the coefficient of the correction term are determined so that

[0014] Therefore, by setting the coefficient of each correction term so that the difference between the curvature in the X direction and the curvature in the できるだけ direction is made as small as possible, it is possible to keep the roundness error within a certain range while maintaining a peak in design. The ratio SR (%) of the maximum side lobe intensity to the intensity can be reduced.

The beam shaping condenser lens according to one embodiment of the present invention has a correction term in which the correction term fe (x, y) is an even function of X, fe (X) and a correction term in which the even function of Y, fe (y) is also Term and an even function of X

1 2

The correction term fe (X) consisting of is also a term power of one or more even powers of X, and the correction term fe (y) force consisting of an even function of Y is also one or more term powers of even powers of Y.

2

[0016] Therefore, the equation of the correction term is simplified and is easy to handle.

The beam shaping condenser lens according to one embodiment of the present invention has a correction term in which the correction term fe (x, y) also has an even function fe (X) force of X and a correction term in which the even function fe (y) force of Y also exists. Term and an even function of X

1 2

The correction term fe (X) consists of one or more term forces including the trigonometric function of X, and the correction term fe (y) force consisting of the even function of Y also becomes one or more term forces including the trigonometric function of Y .

2

[0018] Therefore, the equation of the correction term is simplified and is easy to handle.

The beam shaping condenser lens according to one embodiment of the present invention includes Mouth file has the formula

[Number 2]

Is represented by

[0020] The correction term is obtained by multiplying the power of X and the power of Y. For example, the magnitude of the correction of Y can be changed according to the magnitude of X. Therefore, it is advantageous when designing a beam shaping condenser lens having a large numerical aperture.

[0021] The beam shaping collimating lens according to the present invention is such that, in the XYZ coordinate system, the transmitted collimating beam has no aberration with respect to an incident beam having a different object numerical aperture in the X and Y directions with the Z axis as the optical axis. When condensed by an ideal lens, the beam is shaped so that the area where the intensity of the condensed beam in a cross section perpendicular to the traveling direction is equal to or more than a predetermined ratio with respect to the peak intensity becomes a perfect circle. The profile force between the entrance side and the exit side An equation that includes a term representing the aspheric surface and multiple correction terms that can be represented by fe (x, y) satisfying fe (x, y) = fe (-x, y) [ Number 3]

And the coefficients of each correction term can be determined independently of each other. The circularity error, which is the ratio of the diameter of the cross section in the X direction to the diameter in the Y direction,

CE = I 100-roundness I (%)

NAR = NAX / NAY

ICCI ² X SR ² X CE X NAR ⁴ <0.02

X Y

The coefficient of the term representing the aspherical surface and the coefficient of the correction term are determined so that [0022] Therefore, the coefficient of each correction term is determined so that the difference between the curvature in the X direction and the curvature in the Y direction is as small as possible. The ratio SR (%) of the maximum side lobe intensity to the intensity can be reduced.

The beam shaping collimating lens according to an embodiment of the present invention has a correction term in which the correction term fe (X, y) also has an even function fe (x) force and a correction term in which the Y even function fe (y) force also has And the even of X

1 2

The correction term fe (X) is one or more even powers of X, and the correction term fe (y) consisting of an even function of Y is one or more even powers of Y. .

2

[0024] Therefore, the equation of the correction term is simplified, and it is easy to handle.

[0025] The beam shaping collimating lens according to one embodiment of the present invention has a correction term in which the correction term fe (X, y) also has an even function fe (x) force and a correction term in which the even function fe (y) force of Y also has And the even of X

1 2

The correction term fe (X), which is also a functional force, is also one or more term forces including trigonometric functions of X, and the correction term fe (y) force, which is an even function of Y, is one or more term forces including trigonometric functions of Y. Become.

2

[0026] Therefore, the equation of the correction term is simplified, and it is easy to handle.

[0027] The beam shaping collimator 'lens according to one embodiment of the present invention has a profile of the entrance side and the exit side, where

[Number 4]

Is represented by

Since the correction term is a product of the power of X and the power of Y, for example, the magnitude of the correction of Y can be changed according to the magnitude of X. Therefore, it is advantageous when designing a beam shaping condenser lens having a large numerical aperture.

Brief Description of Drawings

FIG. 1 shows a cross-sectional view along the XZ plane of a beam shaping / condensing integrated lens according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the YZ plane of a beam shaping / condensing integrated lens according to an embodiment of the present invention. Show.

FIG. 3 is a cross-sectional view of an XZ plane of a beam shaping collimator 'lens according to one embodiment of the present invention.

FIG. 4 is a cross-sectional view of the beam shaping collimator ′ lens according to one embodiment of the present invention, taken along the YZ plane.

FIG. 5 shows a point image intensity distribution diagram of the integrated beam shaping / condensing lens according to one embodiment of the present invention.

FIG. 6 shows a spot cross-sectional view including a peak of the integrated beam shaping / condensing lens according to one embodiment of the present invention.

FIG. 7 shows a point image intensity distribution diagram of a beam shaping / condensing integrated lens according to a conventional technique.

FIG. 8 shows a cross-sectional view of a spot including a peak of a conventional integrated beam shaping / condensing lens.

FIG. 9 shows a point image intensity distribution diagram of a beam shaping / condensing integrated lens according to another embodiment of the present invention.

FIG. 10 is a cross-sectional view of a spot including a peak of a beam shaping / condensing integrated lens according to another embodiment of the present invention.

FIG. 11 shows a point image intensity distribution diagram of a beam shaping / condensing integrated lens according to a conventional technique.

FIG. 12 shows a spot cross section including a peak of a conventional beam shaping / condensing integrated lens.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a cross-sectional view on the XZ plane of the integrated beam shaping / condensing lens according to one embodiment of the present invention, and FIG. 2 is a cross-sectional view on the YZ plane. The divergence angle in the YZ plane is larger than the divergence angle in the XZ plane. Therefore, on the object side surface (S1 surface), the roundness is adjusted by setting + power (direction to converge) in the Y direction, and -power (direction to diverge) in the X direction.

FIG. 3 shows a cross-sectional view in the XZ plane of the beam shaping collimator ′ lens according to an embodiment of the present invention, and FIG. 4 shows a cross-sectional view in the YZ plane. The divergence angle in the YZ plane is larger than the divergence angle in the XZ plane. Therefore, on the object side surface (S1 surface) of the lens, The roundness is adjusted by setting the positive power to the convergence direction and the negative power to the divergence direction in the X direction. Note that the image side surface of the lens is called an S2 surface.

[0032] Table 1 shows the initial conditions for the design of the beam shaping / condensing integrated lens. LD-S1 plane indicates the distance between the semiconductor laser light source and the S1 plane of the lens. BF indicates the back focus of the lens. The aperture ratio is determined from the following equation.

[0033] Aperture ratio = object side numerical aperture in the X direction Object side numerical aperture in the ZY direction

According to Table 1, the object-side numerical aperture in the Y direction is 0.4, the aperture ratio is 0.36, the wavelength used is 408 nm, the distance between the semiconductor laser light source and the SI surface of the lens is 1. Omm, and the lens center thickness Is 3.4 mm and the back focus is 100 mm.

[0034] Table 2 shows the initial conditions for the design of the beam shaping collimator 'lens. The LD-S1 plane and aperture ratio are defined as in Table 1. Collimated light is focused by an ideal lens without aberration. According to Table 2, the numerical aperture on the object side in the Y direction is 0.4, the aperture ratio is 0.36, the operating wavelength is 408 ηm, and the distance between the semiconductor laser light source and the SI surface on the light source side of the lens is 1. Omm The center thickness of the lens is 3.4 mm, and the focal length of the ideal lens is 4 mm.

[table 1]

[Table 2] Y direction 0.4

Object side numerical aperture

Ray definition X direction 0.1 4

Aperture ratio x / y 0.36

Working wavelength nm 408

LD ~ S 1 side mm 1

Lens center thickness mm 3.4

Ideal lens focal length mm 4

[0035] The intensity distribution of the beam from the semiconductor laser light source is a Gaussian distribution. Also, based on the light intensity distribution reproducing the semiconductor laser light source and the point spread intensity distribution calculated from the wavefront aberration force, the region having an intensity of 13.5% (1 / e ² ) or more of the peak value was obtained. , The spot diameter in the X and Y directions are determined, and the roundness is determined from the following equation.

[0036] Roundness (%) = spot diameter in X direction Spot diameter in ZY direction X 100

The value of the side lobe is the percentage of the highest value of the side lobe to the peak value in the point image intensity distribution.

[0037] In the design, the light acquisition efficiency is set to 94% or more, and the roundness is set to 95% or more. Also, the wavefront aberration is set to 3 m RMS or less. Also, the virtual image angles in the X and Y directions should be aligned. The virtual image angle in the X direction is the angle between the outermost ray of the light beam and the optical axis on the XZ plane including the image point. The virtual image angle in the Y direction is the angle formed by the outermost ray of the ray bundle with the optical axis on the YZ plane including the image point. The unit is degree. Note that the refractive index of the lens is determined by the wavelength. For example, at 408 nm, 1.5056, at 780 nm,! /, And at 1,4855. As the design software, CODE V of Optical Research Associate, USA was used. However, the present invention can be applied to a case where other design software is used.

[0038] The results of designing the shape of both surfaces of the lens according to the following formula, which is one embodiment of the present invention, by changing the design conditions of the beam shaping / condensing integrated lens variously from the initial conditions in Table 1 are shown. The results are shown in Tables 3-5. [Number 5]

Where Z is the sag amount of the surface parallel to the Z axis (optical axis direction), C and C are the curvatures in the XZ and YZ planes, and K and K are the shapes in the XZ and YZ planes. Conic coefficients, A and B are correction factors

2i represents a 2j number. Specifically, Tables 3 to 5 show the distance between the semiconductor laser light source and the S1 surface of the lens when the force other than the knock focus is changed and when the object-side numerical aperture in the Y direction is changed to 0.45. Was changed to 1.5 mm, the lens center thickness was changed to 3 mm, the wavelength used was changed to 780 nm, the aperture ratio was changed to 0.53, and the aperture ratio was 0.59. The design results when the back focus is set to 100 mm (initial condition), 50 mm, and 20 mm, respectively, are shown. Tables 6 to 9 show the coefficient of the term representing the aspherical surface and the coefficient of the correction term when the design is performed under the above various design conditions. However, the curvature of the S1 surface is omitted because it is shown in Tables 3-5.

[Table 3]

In the initial condition, change BF to NA of 0.45 and change BF LD-S1 surface to 1.5 (mm) Item Unit, etc.

Change BF Change object side Y direction 0.4 <-<one 0.45 ku-<-0.4 ku-ku-Numerical aperture X direction 0.14 <-<-0.17 <one <-0.14 <-<-ray

Aperture ratio x / y 0-36 0.36 0.36 0.37 0.37 0.37 0.36 0.36 0.36 Definition

X direction 0.56 1.12 2.38 0.66 1.32 3.19 0.64 1.28 3.13 Virtual image angle

Y direction 0.56 1.12 2.89 0.66 1.30 3.32 0.66 1.32 3.28 Wavelength used Crm) 408 <one <one <-one-<-<one <-light acquisition efficiency% 94.3 94.3 94.4 94.7 94.8 94.7 94.5 94.5 94.5

LD to S1 surface (mm) 1 1 1 1 1 1 1.5 1.5 1.5 Lens center thickness (mm) 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4

BF (mm) 100 50 20 100 50 20 100 50 20

S1 surface Y curvature 0.83 0.83 0.79 0.81 0.81 0.80 0.73 0.73 0.7

S1 surface X curvature -1.21 -1.22 -1.37 -1.24 -1.26 -1.37 -1.14 -1.16 -1.27

S1 surface curvature change 2.04 2.06 2.16 2.05 2.07 2.17 1,87 1.89 1.97

X direction 39.74 19.91 7.70 34.35 17.18 6.88 34.70 17.27 6.71 Spot diameter

Y direction 40.83 20.49 7.93 35.06 17.51 7.00 35.53 17.64 6.88 Image plane Roundness x / y (¾) 97.34 97.17 97.09 97.99 98.12 98.19 97.66 97.86 97.57 Evaluation Roundness error (%) 2.66 2.83 2.91 2.01 1.88 1.81 2.34 2.14 2.43

Side lobe 0.23 0.25 0.31 0.21 0.25 0.38 0.26 0.28 0.30 Wavefront aberration m A RMS 0.22 0.22 0.30 1.45 1.61 1.94 1.5 2.08 2.55 Evaluation function EF 0.020 0.021 0.029 0.014 0.016 0.029 0.028 0.026 0.037

[Table 4]

Set the lens center thickness to 3 (mm), use wavelength 780 (nm), and set BF to item unit etc.

Change BF Change

Object side aperture Y direction 0.4 <_ <_ 0.4 <one <-number X direction 0.14 <-<-0.14 <-<-line

Aperture ratio x / y 0.36 0.36 0.36 0.36 0.36 0.36 Definition

X direction 0.53 1.07 2.68 0.57 1.14 2.79 Virtual image angle

Y direction 0.54 1.08 2.73 0.56 1.14 2.84 Operating wavelength nm <---<_ 780 <_ <-Light acquisition efficiency 94.4 94.4 94.4 94.3 94.4 94.3

LD ~ S1 surface mm 1 1 1 1 1 1 Lens center thickness 3 3 3 3.4 3.4 3.4

BF mm 100 50 20 100 50 20

S1 surface Y curvature 0.88 0.87 0.85 0.86 0.85 0.85

S1 surface X curvature -1.33 -1.35-1.45 -1.24 -1.27 -1.35

S1 surface curvature change 2.20 2.22 2.30 2.10 2.12 2.20

X direction 41.89 20.88 8.24 75.65 37.46 15.07 Spot diameter

Y direction 43.08 21.49 8.49 77.67 38.47 15.51 Unit roundness x / y (%) 97.23 97.15 97.16 97.40 97.37 97.21 Evaluated perfect circularity (%) 2.77 2.85 2.84 2.60 2.63 2.79

Side lobe 0.23 0.24 0.30 0.24 0.24 0.34 Wavefront aberration mA RMS 0.26 0.30 0.42 0.14 0.14 0.14 Evaluation function EF 0.024 0.023 0.030 0.022 0.019 0.034

[Table 5] Set the 比 aperture ratio of the light source to 0.53 and the XY aperture ratio of the light source to 0.59 Item Unit etc.

Change BF Change BF Object side Y direction 0.4 <_ <-0.4 0.4 0.4 Numerical aperture X direction 0.21 <-G-0.234 0.234 0.234 Ray

Aperture ratio x / y 0.53 0.53 0.53 0.59 0.59 0.59 Definition

X direction 0.57 1.14 3.00 0.59 1.18 3.07 Virtual image angle

Y direction 0.57 1.14 2.91 0.59 1.18 3.00 Wavelength used nm 408 <1 <-408 <-<Light acquisition efficiency 94.4 94.3 94.7 95.9 95.83 96.10

LD ~ S1 side mm 1 1 1 1 1 1 Lens center thickness 3.4 3.4 3.4 3.4 3.4 3.4

BF mm 100 50 20 100 50 20

S1 surface Y curvature 0.82 0.80 0.76 0.78 0.76 0.71

S1 surface X curvature -0.25 -0.26 -0.21 -0.11 -0.11 -0.10

S1 surface curvature change 1.07 1.06 0.97 0.88 0.87 0.81

X direction 39.32 19.54 7.56 39.75 19.78 7.70 Spot diameter

Y direction 40.40 20.02 7.71 38.66 19.20 7.39 Image plane Roundness x / y (%) 97.33 97.59 98.03 102.82 103.02 104.10 Evaluation Roundness error (%) 2.67 2.41 1.97 2.82 3.02 4.10

Side lobe 0.24 0.23 0.25 0.19 0.19 0.25 Wavefront aberration m λ RMS 0.44 0.40 0.50 0.61 0.56 0.56 Evaluation function EF 0.028 0.019 0.012 0.019 0.017 0.026

[Table 6]

/ vu / O εεεsa osooifcld 9 / 880SOSAV

Light source aperture ratio changed to 0.53 I Light source aperture ratio changed to 0.59

100 50 20 100 50 20

KX -22.8497 -26.6845 -51.7997 -120.6219 -125.9646 -215.6601

KY -2.0494 -2.0719 -2.1479 -2.1072 -2.1396 -2.2606

A4 -0.1203 -0.1989 0.5715 -0.0768 -0.1201-0.3551

A6 -0.0041 -0.0295 -0.1311 0.0130 0.0161 0.0335

S1 side

A8 0.2277 0.4688 1.2449 0.0643 0.1222 0.5090

B4 0.0 Ϊ 24 0.0142 0.0163 0.0091 0.0117 0.0163

B6 0.0009 0.0005 -0.0001 0.0016 0.0009 -0.0005

B8 -0.0002 -0.0001 0.0000 -0.0003 -0.0002 0.0000 Free foam surface

KX -0.5830 -0.5685 -0.4872 -0.5335 -0.5225 -0.4816

KY 3.8558 3.1200 1.1572 1.5436 1.3320 0.4494

A4 -0.0040 -0.0049 -0.0108 -0.0027 -0.0032 -0.0076

A6 -0.0008 -0.0010 0.0012 -0.0005 -0.0006 0.0006

S2 surface

A8 0.0001 0.0003 -0.0001 0.0001 0.0002 0.0001

B4 0.0377 0.0378 0.0356 0.0308 0.0309 0.0294

B6 0.0066 0.0072 0.0072 0.0048 0.0054 0.0057

B8 0.0000 0.0005 0.0011 -0.0001 0.0003 0.0009

CY -0.19 -0.22-0.31 -0.22 -0.25 -0.34

CX -0.54 -0.56 -0.61-0.52 -0.54 -0.59

[0040] The design conditions of the integrated beam shaping / condensing lens were variously changed from the initial conditions in Table 1, and the results of designing the shape of both surfaces of the lens according to the following formula (anamorphic formula) according to the conventional technology are shown. 10 to 12 show.

[Number 6]

Ζ (χ) = —— ^χ '' + R [(l-AP) x ² + (1 + AP) y ² ] ² + l + ^ l- (l + k _x ) (c _x ² x ² )- (l + k _y ) (c _y ² y ² )

BR [(l-BP) x ² + (1 + BP) y ² f + CR [(1-CP) x ² + (1 + CP) y ² ] ⁴ + DR [(\-DP) x ² + ( 1 + DP) y ² ] ⁵

(2)

[0041] Here, Z is the sag amount of the plane parallel to the Z axis (the optical axis direction), C and C are the curvatures in the XZ plane and the YZ plane, and K and K are in the XZ plane and the YZ plane. Conical coefficients of the shape, AR, BR, CR, D

R, AP, BP, CP, and DP represent correction factors. Specifically, Tables 10 to 12 show that when the force other than the back force is changed, the object side numerical aperture in the X direction is changed to 0.45. When the distance between the semiconductor laser light source and the SI surface of the lens was changed to 1.5 mm, when the lens center thickness was changed to 3 mm, when the wavelength used was changed to 780 nm, the aperture ratio was 0.53. The design results when the back focus was set to 100 mm (initial condition), 50 mm, and 20 mm, respectively, when the aperture ratio was changed and when the aperture ratio was changed to 0.59. Tables 13 to 16 show the coefficient of the term representing the aspherical surface and the coefficient of the correction term when the design is performed under the above various design conditions. However, the curvature of the S1 surface is shown in Tables 10 to 12 and is omitted because it is! /.

[Table 10] Under initial conditions, change BF to NA 0.45 and change BF LD-S1 surface to 1.5 (mm) Item Unit etc.

Change BF due to change Object side aperture Y direction 0.4 <-<-0.45 <-g-0.4 <-<-number X direction 0.14 く-<-0.17 <_ <-0.14 <-<-Light

Aperture ratio x / y 0.36 0.36 0.36 0.37 0.37 0.37 0.36 0.36 0.36 Definition

X direction 0.53 1.04 2.81 0.65 1.25 3.24 0.61 1.17 3.20 Virtual image angle

Y direction 0.56 1.12 2.B9 0.73 1.38 3.27 0.66 1.32 3.28 Operating wavelength nm 408 <-G-<-K-G--G-<-<-Light acquisition efficiency 94.5 94.6 94.5 94.F 94.8 94.9 94.5 94.5 94.3

LD ~ S1 side mm 1 1 1 1 1 1.5 1.5 1.5 Lens center thickness 3,4 3,4 34 3.4 3.4 3.4 3.4 3.4 3.4

BF mm 100 50 20 100 50 20 100 50 20

S1 surface Y curvature 0.96 0.99 0.76 0.94 0.97 0.66 0.86 0.Θ1 0.65

S1 surface X curvature -1.18 -1.19 -1.66 -1.49 -1.34 -1.82 -1.09 -1.09 -1.40

S1 surface curvature change 2J4 2.19 2.42 2.43 2.32 2.47 1.95 2.00 2.05

X direction 42.02 21.06 7.64 34.18 17.79 6.56 37.2 18.70 6.82 Spot diameter

Y direction 43.47 21.99 7.89 35.70 18.56 6.76 38.43 19.56 6.94 Image plane Roundness X y y y%) 96.65 95.77 96.87 95.75 95.89 97.04 96.81 95.61 98.13 Evaluation True circular error (%) 3.35 4.23 3.13 4.25 4.11 2.96 3.19 4.39 1.82

Side mouth 0.34 0.41 0.63 0.39 0.38 0.8 0.37 0.44 0.43 Wavefront aberration mA RMS 0.5 0.5 1.3 1.3 0.8 7.8 0.34 2.0 2.97 Evaluation function EF 0.059 0.097 0.159 0.140 0.099 0.277 0.084 0.145 0.046 [Table 11]

[Table 12] Set the XY aperture ratio of the light source to 0.53 and the ΧΥ aperture ratio of the light source to 0.59 Item Unit, etc.

Change BF Change BF Object side Y direction 0.4 dots-<-0.4 0.4 0.4 Numerical aperture X direction 0.21 dots-0.234 0.234 0.234 line

Aperture ratio x / y 0.53 0.53 0.53 0.59 0.59 0.59 Definition

X direction 0.59 1.21 2.75 0.62 1.22 3.03 Virtual image angle

Y direction 0.57 1.14 3.00 0.59 1.18 3.00 Wavelength used nm 408--408--<-Light acquisition efficiency 94.9 94.8 94.9 95.9 95.3 95.7

LD-S1 side mm 1 1 1 1 1 1 Lens center thickness 3.4 3.4 3.4 3.4 3.4 3.4

BF mm too 50 20 100 50 20

S1 surface Y curvature 0.64 0.60 0.90 0.63 0.63 0.63

S1 surface X curvature -0.46 -0.52 -0.31 -0.26 -0.27 -0.32

S1 surface curvature change 1.10 1.12 1.22 0.90 0.90 0.95

X direction 37. Ϊ6 18.21 7.83 37.94 19.08 7.57 Spot diameter

Y direction 37.74 18.50 8.12 36.69 18.28 7.27 Image plane Roundness x / y (%) 98.49 98.45 96.36 103.40 104.40 104.18 Evaluation Roundness error C%) 1.51 1.55 3.64 3.40 4.40 4.18 Sidelobe 0.55 0.68 0.45 0.47 0.5 0.44 Wavefront aberration mA RMS 2.8 4.1 5.1 1.03 0.81 5.09 Evaluation function EF 0.086 0.118 0.110 0.141 0.179 0.111

[Table 13] / vu / O εεεsa osooifcld 9 / 880sosAV

S16

Light source aperture ratio changed to 0.53 Light source aperture ratio changed to 0.59

100 50 20 100 50 20

KX -1.9276 -1.6073 -15.1489 -4.7345 -4.3271 -2.9793

KY 0.4232 0.7647 -1.8575 0.3303 0.3305 0.3160

AR -0.0093 -00075 -0.0063 -0.0090 -0.009D -0.0094

BR 0.0009 0.0000 0.0000 0.0000 0.0002 0.0009

S1 side

CR 0.0000 0,0000 -D.0121 ο.αοοο 0.0000 00000

AP 0.9645 0.7044 1.1919 1.1562 1.1619 1.2127

BP -0.5363 6.9836 12.6178 -20172 -1.1730 -0.0596 Anamorphic CP 3.8257 4.5186 D.5400 3.7163 37125 3.6972 Aspheric surface KX -0.4936 -0.5243 -0.5934 -0.4951 -0.5239-0.6184

KY 0.2212 0.0833 -1.4570 G.3562 -0.4004 -0,5741

AR 0.0074 0.0076 0,0034 0.0063 0.0064 0.0060

BR 0.0010 0.0001-0.0026 0.0010 0.0010 0.0010

S2 surface

CR 0.0007 0.0010 00002 0.0004 0.0004 0.0003

AP 1.0507 1.0447 1.7861 1.0Π7 1.0025 1.0013

BP 0.9700 1.2293 08099 0.9143 0.9144 0.9228

CP 1.1133 1.0550 1.0755 1.0410 1.0292 0.9596

CY -0.29 -0.33 -0.21 -0.29 -0.31-0.38 cx -0.57 -0.60 -0.93 -0.54 -0.56 -0.63

The distance between the light source of the incident beam and the side of the light source of the lens is FF (mm), the back force of the lens is BF (mm), and the roundness error is

CE = | 100-roundness I (%)

The object numerical aperture in the X direction is NA, the object numerical aperture in the Y direction is NA, and the object numerical aperture is

X Y

NAR = NA / NA

X Υ

ICCI ² XSR ² Xlog (BF) XCEXNAR ⁴ XFF

X Υ 10

Is the evaluation function EF1.

In Tables 3 to 5 showing the design results according to the embodiment of the present invention, the evaluation function EF1 satisfies the following conditions under all the above design conditions.

EF1 <0.04 On the other hand, in Tables 10 to 12, which show the design results based on the anamorphic aspherical formula, the evaluation function EF1 satisfies the following conditions under all the above design conditions.

EF1> 0.04

Further, according to one embodiment of the present invention, the values of the side lobes under the conditions of Tables 3 to 5 are the values of the side lobes under the corresponding conditions of Tables 10 to 12 according to the conventional anamorphic equation. Less than.

[0046] The above results are considered to be due to the following reasons. Relatively large side lobes occur at the periphery of the XZ section. Considering the XZ cross section, since the power of the surface to be diverged for beam shaping becomes large near the center where the power of the square term of the term representing the aspheric surface is strong, a relatively strong divergence is obtained. Occurs. Therefore, it is considered that the area near the center becomes coarse and the area around the center becomes dense, and the side lobes increase. Therefore, in order to reduce the side lobe, it is considered preferable to minimize the difference between the curvature C in the X direction and the curvature C in the Y direction in a term representing an aspheric surface.

On the other hand, the correction term is different between the equation (Equation 1) according to the embodiment of the present invention and the conventional anamorphic equation (Equation 2). In Equation 1, the coefficients A and B of each correction term are independent of each other.

2i 2i

Can be determined. Therefore, in the present embodiment, the coefficients A and B of each correction term are

2i 2i By defining them independently of each other, the difference between the curvature C in the X direction and the curvature C in the Y direction of the term representing the aspheric surface in Equation 1 can be minimized. However, in Equation 2, AP

, BP, CP, DP, etc., are common to multiple correction terms, and cannot be determined independently of each other.The curvature C in the X direction and the curvature C in the Y direction of the aspherical term Cannot be reduced as in the present invention! /.

[0048] The form of the conventional anamorphic equation (Equation 2) corresponds to the form of the following aspherical equation.

[Number 7]

2

Z = ^ ° '+ Y aip ²ⁿ

1 + ^ / 1— (1 + n) c ² r ²

[0049] Here, r and p are distances from the optical axis. In fact, in Equation 2, if cx = cy, kx = ky, AP = BP = CP = DP = 0, the result is the same as that of the above-mentioned aspheric surface. AP, BP, CP The DP term and the DP term indicate the difference between the amount of sag on the X axis and the amount of sag on the Y axis, and can easily correspond to astigmatism. For this reason, the conventional anamorphic equation (Equation 2) has been generally used.

[0050] As described above, the beam shaping condenser lens according to one embodiment of the present invention converts the beam from the semiconductor laser light source having different divergence angles in the X and Υ directions from the intensity of the focused beam. When shaping the beam so that the power distribution achieves a predetermined circularity, the side lobe can be reduced as compared with the conventional anamorphic lens.

[0051] In general, considering the symmetry of the lens, the correction term fe (X, y) is

fe (x, y) = ie, — x, — y)

Need to be satisfied.

[0052] The correction term may include a trigonometric function term! The trigonometric function has a large change in curvature! /, So it can be designed with a higher degree of freedom by combining it appropriately. A design example of a correction term including a trigonometric function will be described later.

[0053] The correction term may include a term obtained by multiplying a power of X and a power of Y. If this correction term is used, for example, the magnitude of Y correction can be changed according to the magnitude of X. Therefore, it is advantageous when designing a beam shaping condenser lens having a large numerical aperture. A design example of a correction term including a term obtained by multiplying the power of X and the power of Y will be described later.

Table 17 shows the results of designing according to the following formula, which is an embodiment of the present invention, by variously changing the design conditions of the beam shaping collimator lens from the initial conditions in Table 2.

[Equation 8]

[0055] Specifically, Table 17 shows that the distance between the semiconductor laser light source and the S1 surface of the lens is obtained when the initial condition is not changed, when the object-side numerical aperture in the X direction is changed to 0.45, and Was changed to 1.5 mm, the lens center thickness was changed to 3 mm, the wavelength used was changed to 780 nm, the aperture ratio was changed to 0.53, and the aperture ratio was set to 0.59. The design results when changing are shown. In Tables 17 to 20, the circled numbers in the tables indicate The above seven cases are shown, respectively. Table 18 shows the coefficients other than the curvature of the term representing the aspheric surface and the coefficients of the correction term when the design is performed under the above various design conditions.

[Table 17]

[Table 18] ① ② ③ ④ ⑤ ⑥ ⑦

KX -0.8123 -0.8041 -0.7532 -0.7634 -0.7901 -22.7868 -140.5968

KY -1.1 168 -1.1263 -1.2915 -1.1 604 -1.0665 -2.0410 -2.1048

A4-0.5702 -0.5474 -0.3488 -0.6362-0.6032 -0.0876 -0.0640

A6 -2.3072 -2.5250 -0.9916 -2.7573 -2.6010 0.0026 0.0127

S1 side

A8 -4.231 7 -5.7562 -1.6361 -5.9845 -4.9857 0.1 51 9 0.0544

B4 -0.0440 -0.0368 -0.01 10-0.0374 -0.0501 0.01 1 9 0.0092

B6 0.0147 0.01 10 0.0041 0.0147 0.01 61 0.001 0 0.0015

B8 -0.0023 -0.0014-0.0004 -0.0023 -0.0025 -0.0002-0.0003 Freeform surface

KX -0.3253 -0.3267 -0.3644-0.3478 -0.3430 -0.6034 -0.5654

KY 6.7296 5.2018 28.3452 13.3083 6.2441 5.1314 2.1879

A4 0.001 1 0.001 5 0.0003 0.0007 0.001 1 -0.0040 -0.0032

A6 -0.0005-0.0007 -0.0005 -0.0010 -0.0006 -0.0007 -0.0005

S2 surface

A8 0.0002 0.0002 0.0000 0.0002 0.0002 0.0001 0.0001

B4 0.0438 0.0420 0.0380 0.0596 0.0461 0.0379 0.031 1

B6 0.0081 0.0091 0.0052 0.01 24 0.0091 0.0062 0.0047

B8 -0.0020 -0.0020 -0.001 2 -0.0035 -0.0021 -0.0003 -0.0002

CY -0.16 -0.18 -0.08 -0.13 -0.1 7 -0.1 7 -0.1 9

CX -0.63 -0.63 -0.61 -0.70 -0.65 -0.52 -0.49 By changing the design conditions of the beam shaping collimator lens variously from the initial conditions in Table 2, the following formula (anamorphic formula) based on the conventional technology is used. Therefore, the design results are shown in Table 19.

[Equation 9] c + cy

■ + R [(l-ΑΡ) χ ^Δ + Q + AP) y ² f + l + ^ l-(l + k _x X) — (l + n _y ) { _C ; _y ^l )

BR [(l-BP) x ² + (1 + BP) y ² ] ³ + CR [(1 CP) x ² + (1 + CP) y ² ] ⁴ + DR [(l-DP) x ² + (1 + DP) y ²

(2) Specifically, Table 19 shows that the distance between the semiconductor laser light source and the S1 surface of the lens was obtained when the initial conditions were not changed and the object-side numerical aperture in the X direction was changed to 0.45. Was changed to 1.5 mm, the lens center thickness was changed to 3 mm, the wavelength used was changed to 780 nm, the aperture ratio was changed to 0.53, and the aperture ratio was set to 0.59. The design results when changing are shown. Table 20 shows the case where the design was performed under the above various design conditions. The following shows the coefficients other than the curvature of the term representing the aspheric surface and the coefficients of the correction term.

[Table 19]

[Table 20] ① ② ③ ④ ⑤ ⑥ ⑦

KX -0.3649 2.4392 0.4517 -0.4555 -0.0856 -2.0478 -4.2244

KY -2.2732 -2.0345 -2.4986 -2.1591 -2.1472 0.3814 0.0850

AR 0.0086 0.0081 -0.0090 -0.0021 0.0065 -0.0096 -0.0089

BR 0.0026 0.0002 0.0029 0.0035 0.0042 0.0009 -0.0001

S1 side

CR -0.0009 0.0000 -0.0001 -0.0009 0.0000 0.0000 0.0000

AP -1.7945 -0.0845 -2.5032-1.4227 -2.3539 1.0191 1.3303

BP 0.1926 -0.2713 0.0451 0.6201 -0.1832 -0.1795 -2.0666 Anamorphic CP -0.0944 -1.6930 1.6484 0.3839 0.8780 3.7913 2.9994 Aspheric surface KX -0.4541 -0.2729 -1.6869 -0.4612 -0.4639 -0.4607 -0.4551

KY 15.6245 -25.9128 25.8019 295.4299 2.1947 0.3394 -0.6086

AR 0.0026 0.0050 -0.0095 0.0015 0.0072 0.0072 0.0065

S2 surface BR 0.0001 0.0010 0.0000 0.0021 0.0001 0.0010 0.0012

CR 0.0001 0.0000 -0.0001 0.0002 0.0000 0.0006 0.0003

AP 1.4417 0.2761 -1.5830 1.0030 1.1666 1.0640 0.9904

-0.2827 0.1705 13.8995 0.6500 0.2389 0.9880 0.8331

BP

CP 1.2442 -1.6344 -ΐ.22δ7 1.2474 1.6812 1.1165 1.0039

CY -0.04 0.12 -0,10 0.02 -0.11 -0.27 -0.26

CX -0.62 -0.60 -0.73 -0.69 -0.65 -0.55 -0.52

[0058] The roundness error

CE = | 100-roundness I (%)

X Y

NAR = NA / NA

X Υ

I C -C

XYI ² XSR ² XCEXNAR ⁴

Is the evaluation function EF2.

[0059] In Table 17 showing the design result according to the embodiment of the present invention, the evaluation function EF2 satisfies the following condition under all the above design conditions.

EF2 <0.02

[0060] On the other hand, in Table 19 showing the design result by the anamorphic aspherical formula, the evaluation function EF2 satisfies the following condition under all the above design conditions.

EF2> 0.02 [0061] Further, according to the embodiment of the present invention, the value of the side lobe under each condition in Table 17 is smaller than the value of the side lobe under the corresponding condition in Table 19 according to the conventional anamorphic equation.

[0062] The reasons for the above results for Tables 17 to 20 are considered to be the same as the reasons for the results for Tables 3 to 16.

[0063] Thus, the beam shaping collimator 'lens according to one embodiment of the present invention is capable of converting a beam from a semiconductor laser light source having different divergence angles in the X and Y directions from the intensity of the focused beam. When shaping the beam so that the distribution achieves a predetermined roundness, sidelobes can be reduced as compared to a conventional anamorphic lens.

[0064] Among the design examples shown in Tables 3 to 6 of the integrated beam shaping condensing lens according to the embodiment of the present invention, the following design examples (Table 21) include a point image intensity distribution diagram and peaks. The cross section of the spot (Figures 5 and 6, 9 and 10) is shown.

[Table 21]

NA (Y direction) 0.4 0.45

NA (X direction) 0.14 0.17

S1 surface Y curvature 0.79 0.80

S1 surface X curvature1.37-1.37

S 1 surface curvature change 2.16 2.17

X direction spot diameter 7.7 6.88

Spot diameter in Y direction 7.93 7.00

Sidelobe 0.31 0.38

BF 20 20

EF 0.029 0.029

PSF diagram Fig. 5 Fig. 9

Spot cross section Fig.6 Fig.10 Among the design examples shown in Tables 10 to 12 of the beam shaping condensing integrated lens according to the prior art, for the following design example (Table 22), a spot cross-sectional view including a point image intensity distribution diagram and a peak (FIG. 7 and FIG. 8, Figures 11 and 12) are shown.

[Table 22]

FIGS. 5 and 6 show the design results (in the case of numerical aperture of 0.4 in the Y direction) of one embodiment of the present invention.

When comparing FIGS. 7 and 8 showing the design results of the prior art, the side lobes in the case of the present invention are reduced as compared with the prior art.

FIGS. 9 and 1 show a design result (in the case of a numerical aperture of 0.45 in the Υ direction) of one embodiment of the present invention

When 0 is compared with FIGS. 11 and 12 showing the design results of the conventional technique, the side lobe in the case of the present invention is reduced as compared with the conventional technique.

Next, Table 23 shows the results of designing under the conditions of Tables 1 and 2 according to the following equation using a trigonometric function as a correction term.

[Number 10] QX ~~ CV ^m "

z = —— ^xy + Y ^X (l-cos (/ a) ') + Y5. x (1 cos (/ zo) l + ^ l- (l + ^) ( _Ct V)-(l + ^) ( V)-= i

(3) Here, a in the correction term of the above equation is a constant for adjustment. The unit of the angle is radian. Specifically, Table 23 shows the design results for the collimated type and the converging type with a back force of 100 mm, 50 mm and 20 mm, respectively. Table 24 shows the coefficients of the equation when the design was performed under the above design conditions.

[Table 23] Object side aperture X direction 0.4 <-<-<-Number Y direction 0.14 <-<-<-Aperture ratio x / y 0.36 0.36 0.36 0.36 Definition

X direction 14.13 0.57 1.15 2.91 Virtual image angle

Y direction 14.20 0.57 1.15 2.93 Wavelength used nm 408 408 408 408 Light acquisition efficiency 94.3 94.3 94.3 94.3 ~ S1 side mm 1 1 1 1

Lens center thickness 3.4 3.4 3.4 3.4

BF mm CO 100 50 20

S1 surface Y curvature 0.83 0.82 0.81 0.80

S1 surface X curvature -1.22 -1.23 -1.26 -1.35

S1 surface curvature change 2.05 2.05 2.07 2.14

X direction 1.59 39.45 19.53 7.69 Spot diameter

Y direction 1.64 40.46 20.06 7.88 Image plane roundness y / x (%) 97.31 97.51 97.37 97.50 Evaluation roundness correction ratio (%) 2.69 2.49 2.63 2.50

0.25 0.23 0.23 0.26 Wavefront aberration mARMS 0.49 0.6 0.73 0.99 Evaluation function EF 0.012 0.019 0.017 0.017 [Table 24]

[0070] In Table 23, the evaluation function EF1 satisfies the following conditions under the integrated light-collecting design condition.

EF1 <0.04

In the collimating design condition, the evaluation function EF2 satisfies the following condition.

EF2 0.02

Further, according to the embodiment of the present invention, the value of the side lobe under each condition of Table 23 is smaller than the value of the side lobe under the corresponding conditions of Tables 10 and 19 by the conventional anamorphic equation. small.

Next, Table 26 shows the results of designing under the conditions of Tables 1 and 2 according to the following equations. [ ^Equation 11] z = ~~ ^xyy ^ + ^ _Cj xx ^2m y ²ⁿ (4)

l + ^ lO + ^) { c x 2 x 2) - {\ + k y) {c y 2 y 2) zone =,

j = [(m + n) ² + m + 3n] / 2, m + n≤5 Table 25 below shows the role of the coefficient Cj of the correction term in the above equation. Specifically, Table 26 shows the design results for the collimated type with the integrated focusing type and the back focus of 100 mm, 50 mm and 20 mm, respectively. Table 27 shows the coefficients of the equation when the design was performed under the above design conditions.

[Table 25]

[Table 26]

Object side 0.4 direction x-<-<-numerical aperture Y direction 0.14 <_ <-<-ray

Aperture ratio x / y 0.36 0.36 0.36 0.36 Definition

X direction deg 14.18 0.56 1.12 2.87 Virtual image angle

Y direction deg 14.15 0.56 1.12 2.89 Operating wavelength nm 408 408 408 408 Light acquisition efficiency% 94.3 94.4 94.3 94.4

LD to S1 side mm 1 1 1 1 Lens center thickness mm 3.4 3.4 3.4 3.4

BF mm Co 100 50 20

S1 surface Y curvature 0.83 0.83 0.83 0.79

S1 surface X curvature -1.2 -1.21 -1.22 -1.37

S1 surface curvature change 2.03 2.04 2.05 2.16

X direction um 1.6 39.81 19.93 7.71 Spot diameter

Y direction um 1.64 40.85 20.51 7.93 Image plane Roundness% 97.56 97.45 97.17 97.23 Evaluation Roundness correction ratio 2.44 2.55 2.63 2.77

Side lobe% 0.23 0.25 0.26 0.3 Wavefront aberration m A RMS 0.22 0.21 0.23 0.28 Evaluation function EF 0.009 0.022 0.021 0.025

[Table 27]

BF Co 100 50 20

kx -0.7982 -0.7650 -0.8493 -0.7673 ky -1.1 159 -1.0402 -1.2044 -0.8170

C3 -0.5736 -0.6008 -0.5799 -0.6942

C4 0.0013 0.0012 -0.0002 -0.0064

C5 -0.0439 -0.0491 -0.0383 -0.0600

C6-2.1512 -2.0153 -1.9575 -4.2737

C 0.3015 0.3190 0.3105 0.4593

S1 side

C8 0.0100 0.0095 0.0109 0.0203

C9 0.0147 0.0149 0.0142 0.0133

C10 -1.9651 -1.9683 -1.4683 3.4094

C1 1 0.7166 0.5933 0.5302 1.4727

C12 -0.1228 -0.1285 -0.1298 -0.2022

C13 -0.0051 -0.0052 -0.0054 -0.0090

C14 -0.0023 -0.0023 -0.0023 -0.0022

Freefo

kx -0.3367 -0.3636 -0.3909 -0.4637

—Muro

ky 6.5033 4.7235 3.5652 0.9168

Sturm surface

C3 0.0007 0.001 1 0.0019 0.0040

C4 -0.0004 -0.0003 -0.0003 -0.0009

C5 0.0437 0.0436 0.0439 0.0379

C6 -0.0004 -0.0003 -0.0001 -0.0005

Coff 0.0010 0.0010 0.001 1 0.001 1

C8 0.0004 0.0005 0.0005 0.0002

S2 surface

C9 0.0082 0.0083 0.0080 0.0066

C10 0.0002 0.0002 0.0002 0.0005

C1 1 0.0000 0.0001 0.0001-0.0001

C12 0.001 1 0.001 1 0.001 1 0.001 1

C13 0.0003 0.0003 0.0002 0.0004

C14 -0.0021-0.0020 -0.0023 -0.001 1

CY -0.1625 -0.1843 -0.2023 -0.2903

CX -0.6286 -0.6496 -0.6705 -0.7404

[0075] In Table 26, the evaluation function EF1 satisfies the following condition under the condensing-integrated design condition.

EF1 <0.04

[0076] In the collimating design conditions, the evaluation function EF2 satisfies the following conditions. EF2 <0.02

Further, according to an embodiment of the present invention, the value of the side lobe under each condition of Table 26 is smaller than the value of the side lobe under the corresponding conditions of Tables 10 and 19 according to the conventional anamorphic equation.

Claims

The scope of the claims

In the XYZ coordinate system, with the Ζ axis as the optical axis, for an incident beam with a different object numerical aperture in the X and Υ directions, the intensity of the focused beam in the cross section perpendicular to the traveling direction Beam-shaping condenser lens for shaping the beam so that an area having a predetermined ratio or more becomes a perfect circle, wherein the profile of the incident side surface and the outgoing side surface represents an aspheric surface, and fe (x, y) = fe (-x, y) An expression containing multiple correction terms represented by fe (x, y) that satisfies [feature 12]

The coefficient of each correction term can be determined independently of each other, the distance between the light source of the incident beam and the side of the light source of the lens is FF (mm), the back focus of the lens is BF (mm), The roundness error, which is the ratio of the diameter in the X direction to the diameter in the Y direction,

CE = I 100-roundness I (%)

NAR = NAX / NAY

ICCI ² X SR ² X log (BF) X CE X NAR ⁴ X FF <0.04

X Υ 10

A beam shaping condenser lens in which the coefficient of the term representing the aspheric surface and the coefficient of the correction term are determined so that

[2] The correction term fe (x, y) consists of a correction term consisting of an even function of X, fe (x), and an even function of Y, fe (y)

1 2

The correction term fe (X) is an even function of X, and the correction term fe (Y) is one or more even powers of X, and the correction term fe (y) is one or more. Term of even power of Y

2

The beam shaping condenser lens according to claim 1, wherein

[3] The correction term fe (x, y) consists of a correction term consisting of an even function of X, fe (x), and an even function of Y, fe (y)

1 2

The correction term fe (X), which consists of a correction term and also has an even function force of X, becomes one or more term forces including trigonometric functions of X, and the correction term fe (y) which also has the even function force of Y 1 including trigonometric functions The beam shaping condenser lens _{c according} to claim 1, wherein

[4] The profile of the entrance side and exit side is

[Number 13]

The beam-shaping condenser lens according to claim 1, wherein j = [(m + n) ² + m + 3 «] / 2, m + n≤5.

[5] In the XYZ coordinate system, when the transmitted collimated beam is focused by an ideal lens with no aberration for the incident beam with different object numerical apertures in the XY directions with the Z axis as the optical axis, A beam shaping collimator 'lens that shapes the beam so that an area having a predetermined ratio or more with respect to the peak intensity in a cross section perpendicular to the traveling direction of the formed beam becomes a perfect circle, Expression that includes a term representing the aspheric surface and a plurality of correction terms represented by fe (x, y) satisfying fe (x, y) = fe (-x, y)

[Number 14]

twenty two

c _x xc ++ cc _yv yy ^,

z =, no + f _e (z, y)

l + \ - (\ + k x) (c x 2 x 2) - (l + k y) (c 2 v y 2)

The coefficient of each correction term can be determined independently of each other, and the error of the circularity, which is the ratio of the diameter of the cross section in the X direction to the diameter in the Y direction, is represented by

CE = I 100-roundness I (%)

NAR = NAX / NAY

ICCI ² XSR ² XCEXNAR ⁴ <0.02

X Y

A beam shaping collimating lens in which the coefficient of the term representing the aspheric surface and the coefficient of the correction term are determined so that [6] The correction term fe (x, y) consists of a correction term consisting of an even function fe (x) of X and an even function fe (y) of Y

1 2 The correction term fe (X), which is the even function of X, is one or more even powers of X, and the correction term fe (y), which is the even function of Y, is 1 Or several even power terms of Y

2

A beam shaping collimating lens according to claim 5.

[7] The correction term fe (x, y) consists of a correction term consisting of an even function of X, fe (x), and an even function of Y, fe (y)

1 2 The correction term fe (X), which consists of the correction term and also has the even function force of X, becomes one or more term forces including the trigonometric function of X, and the correction term fe (y) that also has the even function force of Y 1 including trigonometric functions of Y

2

The beam shaping collimator 'lens according to claim 5, wherein the lens has a plurality of powers.

[8] The profile of the entrance side and the exit side is

[Number 15]

The beam shaping collimating lens of claim 5, represented by: