CN102023392A - Array two-ring phase-ring light uniformity device and manufacturing method whereof - Google Patents

Abstract

The present invention discloses an array two-ring phase-ring light uniformity device, which is characterized in that: the array two-ring phase-ring light uniformity device is an array with a structure of two-ring phase ring on a transparent medium manufactured according to the practical need, wherein, the size of the array is given according to the practical need; the two-ring phase ring is the basic unit of the array type dodging device; two-ring phase ring is a phase plate with a concentric two-ring structure manufactured on a transparent substrate; the radius of the outermost ring is given by the practical optical path; the radius of the inner ring is 0.36 times the radius of the outer ring; the phase of the inner ring is Pi; the phase of the outer ring is 0; the other parts are lightproof. The present invention simultaneously discloses a method for manufacturing array two-ring phase-ring light uniformity device. The invention can implement the wavefront flatting of Gaussian beam and other nonuniform non-planar wavefront beams, and also can implement the dodging of light beam and the wavefront beam approaching the plane, wherein the wavefront beam has a wide application in optical path system.

Description

Array 2 ring positions are encircled light uniforming device and preparation method thereof mutually

Technical field

The present invention relates to shaping technique field, laser beam corrugated, particularly a kind of be used to realize before the high bass wave and before the irregular wave laser beam promptly realize approaching the array 2 ring positions of the light field that plane wave front distributes and encircle light uniforming device and preparation method thereof mutually in the wavefront flat-topization of far field construction light field.This kind array 2 ring position encircles mutually that light uniforming device can be used for beam shaping, microelectronics non-mask etching and other needs in the various light paths of plane wave front.

Background technology

By all means for before the high bass wave and irregular wave before laser beam spare light, make optical beam transformation become to approach that the light beam of plane wave front is the problem of a practicality, in various light paths, all be widely used, such as needing in the various instruments of plane wave front at beam shaping, microelectronics non-mask etching and other.The optical device that can realize this function is referred to as light uniforming device.

Thereby position phase modulation technique is to distribute mutually by the position that changes diffracted ray propagation cross section to realize the technology of expection diffraction intensity distribution.The method that is used to modulate has multiple, the phase board that has fixed bit to distribute mutually, also the modulation sheet that can be distributed mutually by the Control of Voltage position made of using light electric crystal.Because the utilization ratio of diffraction phase board luminous energy is the highest, so the most frequently used.

So-called light uniforming device is also referred to as even bundle device, is that a kind of incident beam wavefront that changes is to realize the optical device of similar plane wave front light beam.General light uniforming device comprises:

Prism method: principle of work is the quasi-parallel laser beam when a branch of light distribution approximate Gaussian function, and during by prism, light beam is divided into four light beams by kaleidoscope prism, and four light beams are after stack on the X-Y plane, and the beam distribution homogeneity has better improvement.(the x of any on X-Y plane, y), through behind the kaleidoscope prism, light intensity on the X-Y plane changes number percent less than 3%, the Laser Transmission rate can reach 94%, can obtain well even effect of output beam and higher Laser Transmission rate with prism method, but the even effect of prism method only just obtains desirable effect when the strict symmetry of input beam, and obtain the extremely strict angle in position in uniform beam cross section corresponding to wedge.

The catoptron method: principle of work is the quasi-parallel laser beam process lens L when a branch of light distribution approximate Gaussian function ₁Focus on mirror M ₁On, through after the primary event, its energy distribution will be passed through lens L equally according to change and energy superposition phenomenon that beam direction takes place shown in Fig. 1-2 ₂And mirror M ₂After, light beam will superpose again.Through after the light beam stack repeatedly, its initial Gaussian beam energy distribution is with homogenized like this.Also can obtain well even effect of output beam and higher Laser Transmission rate with the catoptron method, but the assembling of catoptron method and debugging are very difficult.

The kaleidoscope method: principle of work is for being that the incident light of approximate Gaussian distribution is with maximum incident angle θ when light distribution _MaxAfter entering optical waveguide, have only with lens axis light parallel or become a less angle with optical axis and directly pass through waveguide without reflection, the light of all the other incident lights will produce in waveguide on the difference of reflection arrival output face.The kaleidoscope method makes, debugs simple and easy, and cost reduces greatly, can change the size of output facula easily, but the loss of this system is bigger.

The cylindrical mirror method: the method principle is for being surrounded the square structure of a hollow by four cylindrical mirrors, every cylindrical mirror is installed on the meticulous adjustment rack, by regulating the size and dimension that to control hollow space, laser radiation is on device, hollow space laser directly sees through, be radiated at the strong part of the low light level that light on the edge cylindrical lens will compensate to intermediate light, adjust knob by the parameter and suitable adjusting of calculating cylindrical mirror, just can obtain equal light effect, the advantage of this method is that the light beam transmitance is higher, all light effect is better, but the designer has relatively high expectations, and the designer need calculate lens parameters and design high-precision micro-adjusting mechanism.

Fly's-eye lens array method: principle is a fly_eye lens array condenser system light path, and by the square lens arra L that m * m sheet focal length and measure-alike lenslet are formed, lens array L is divided into m to the collimated light beam corrugated of incident ²The bundle beamlet, actual in the light distribution that forms on the target surface is the integration that spherical mirror is focused at each beamlet the light intensity on its focal plane.Use the lens arra condenser system, even under the very poor situation of incident beam near field distribution homogeneity, still can on the focal plane, obtain uniform lighting effect.

The array light uniforming device, be called the even bundle of array device again, be based on mathematics integral principle design, it can be divided into light beam unlimited a plurality of tiny light beams, the energy distribution of the light beam inside that each is tiny is uniform, penlight accumulative total stack with all has just obtained the hot spot that distributes in a certain position energy even.[referring to, Lin ying, Lawrence Geoge N, Buck Jesse.Charaterization of excimer lasers for application to lenslet arrayhomogenizer[J], Applied Optics, 2001,49 (12): 1931-1941].The basic array unit of array light uniforming device can be lens, and promptly above-mentioned fly eye lens array method also can be that Fresnel zone plate is [referring to Liu Xun, Chen Tao, Zuo Tiechuan is applied to the design studies of the binary optical elements of excimer laser corrugated shaping, Chinese laser (monograph), in March, 2008.]

Given annular position is ring mutually, and its far field construction field light distribution is that a position is encircled each radius and each ring position function mutually mutually.Adopt 2 ring positions to encircle the wavefront flat-topization that can realize the incident Gaussian beam mutually.[referring to Jia Jia, Changhe Zhou, Xiaohui Sun, and Liren Liu, " Superresolutionlaser beam shaping ", Applied optics, vol 43, No.10,2004], the 2 ring positions project organization of ring are mutually provided by actual light path for outer shroud radius, and interior ring radius is 0.84 of an outer shroud radius, the position of interior endless belt is π mutually, and the outer shroud position is 0 mutually.Remaining part is light tight.Perhaps interior endless belt position is 0 mutually, and the outer shroud position is π mutually.

Summary of the invention

(1) technical matters that will solve

In view of this, fundamental purpose of the present invention is to provide a kind of array 2 ring positions to encircle light uniforming device and preparation method thereof mutually, to realize Gaussian beam and other wavefront non-uniform laser beams are transformed to the diffracted beam of wavefront almost plane.

(2) technical scheme

For achieving the above object, the invention provides a kind of array 2 ring positions and encircle light uniforming device mutually, it is a kind of 2 ring positions of making according to actual needs on transparent medium arrays of ring mutually that these array 2 ring positions are encircled light uniforming device mutually, the size of array is provided by actual needs, and this 2 ring position ring mutually is the elementary cell of this kind array type light uniforming device.

In the such scheme, 2 ring positions ring mutually are the position photos of a concentric double ring structure making on transparent substrate, and outer shroud radius is provided by actual light path, and interior ring radius is 0.84 of an outer shroud radius, and the position of interior endless belt is π mutually, and the outer shroud position is 0 mutually.Remaining part is light tight.

In the such scheme, so-called array is exactly this 2 ring position of repetition structure of ring mutually.

For achieving the above object, the present invention also provides a kind of method that array 2 ring positions are encircled light uniforming device mutually of making, and this method utilizes lsi technology technology and plane photoetching process technology to realize, may further comprise the steps:

Utilize the electron-beam direct writing legal system to make mother matrix;

Master pattern is transferred on the optical glass that scribbles photoresist by the contact photolithography method;

Utilize the inductive couple plasma lithographic technique, will move on to pattern etch on the optical glass photoresist in optical glass.

In the such scheme, describedly master pattern is transferred in the step on the optical glass that scribbles photoresist by the contact photolithography method, the error of repelication of described contact exposure is less than 0.5 μ m, and the photoresist that is adopted is Shipley s1818, and thickness is 1.8 μ m.

In the such scheme, in the described step of pattern etch in the optical glass that will move on on the optical glass photoresist, the etching gas that is adopted is fluoroform (CHF ₃), flow is 30SCCM, and RF power is 500W, and bias power is 200W, is 0.077 μ m/min to the etch rate of quartz substrate.

(3) beneficial effect

Array provided by the invention 2 ring positions are encircled light uniforming device mutually, be based on mathematics integral principle design, it can be divided into light beam unlimited a plurality of tiny light beams, the energy distribution of the light beam inside that each is tiny is uniform, penlight accumulative total stack with all has just obtained the hot spot that distributes in a certain position energy even.The elementary cell 2 ring positions of this kind array light uniforming device are ring mutually, it is the diffraction element of a phase-type, its independent function is to realize inciding light beam on it in the wavefront flat-topization in far field, and after incident beam incides this elementary cell, realize the focusing again of light beam and the diffusion in far field, thereby realized the even light of array device.

Description of drawings

Fig. 1 is the basic diffraction element that array 2 ring positions are encircled light uniforming device mutually, and 2 ring positions are the synoptic diagram of ring mutually.Black is that the position is the part of π mutually among the figure, and white is that the position is 0 place mutually, and the part of grey is light tight, and the radius of interior ring is 0.84 times of outer shroud radius;

Fig. 2 is that array 2 of the present invention encircles the synoptic diagram that 10 * 10 arrays, 2 a ring position of encircling one of light uniforming device embodiment is mutually encircled light uniforming device mutually, and diffraction element is Fig. 1;

The a branch of Gaussian beam of Fig. 3 incides the synoptic diagram that array 2 ring positions are encircled light uniforming device mutually.

Fig. 4 is the synoptic diagram of 10 * 10 array Fresnel zone plate light uniforming devices.The basic diffraction element formula Fresnel zone plate of this kind light uniforming device, this kind light uniforming device is published.The purpose that the present invention lists this light uniforming device is array of the present invention 2 ring positions to be encircled light uniforming device mutually and array fresnel's zone plate light uniforming device compares, thereby proves that even light result of the present invention is better than array Fei Nier zone plate light uniforming device.

The a branch of Gaussian beam of Fig. 5 incides the synoptic diagram of array Fresnel zone plate light uniforming device.

Fig. 6 Gaussian beam does not incide any light uniforming device, incides array Fresnel zone plate light uniforming device, incides the intensity contrast figure that array 2 ring positions are encircled the diffracted beam of light uniforming device mutually.Can obviously find out from figure: do not incide any light uniforming device, the light intensity distributions of Gaussian beam is a Gaussian curve.Two kinds of light uniforming devices all are the even light of having realized Gaussian beam, and are better than the even light effect of existing array Fresnel zone plate light uniforming device but array provided by the invention 2 ring positions are encircled the even light effect of light uniforming device mutually.Because it has realized more approaching the diffracted beam of plane wave front.

Fig. 7 is the experiment pick-up unit that array 2 ring positions are encircled light uniforming device mutually.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, the present invention is described in more detail.

It is a kind of novel diffraction optics phase part, i.e. phase board that array 2 ring positions are encircled light uniforming device mutually.This phase board is positioned over before or after the diffraction limit lens, and laser beam far field construction light field is revised, promptly even light, and realization more approaches the diffracted beam of plane wave front than (such as Gaussian beam) before the incident beam irregular wave.The present invention has provided array 2 ring positions and has encircled the project organization of light uniforming device mutually, and has carried out relevant simulated experiment.Experimental verification adopt array 2 ring positions to encircle the flat-topization that light uniforming device can be realized the Gaussian beam wavefront mutually, promptly Gaussian beam is for conversion into the diffracted beam that wavefront approaches plane wave front.The technology of the present invention can be used for beam shaping, microelectronics non-mask etching and other needs in the various light paths of plane wave front light beam.

This array provided by the invention 2 ring positions are encircled light uniforming device mutually, are a kind of 2 ring positions of making according to actual needs on transparent medium arrays of ring mutually, and the size of array is provided by actual needs.So-called 2 ring positions ring mutually are the elementary cells of this kind array type light uniforming device.2 ring positions ring mutually are the position photos of a concentric double ring structure making on transparent substrate.Outer shroud radius is provided by actual light path, and interior ring radius is 0.84 of an outer shroud radius, and the position of interior endless belt is π mutually, and outer endless belt position is 0 mutually.Remaining part is light tight.So-called array is exactly this 2 ring position of repetition structure of ring mutually.

Fig. 2 is that array 2 of the present invention encircles the synoptic diagram that 10 * 10 arrays, 2 a ring position of encircling one of light uniforming device embodiment is mutually encircled light uniforming device mutually, and diffraction element is Fig. 1; Black is that the position is the part of π mutually among the figure, and white is that the position is 0 place mutually, and the part of grey is light tight, and the radius of interior ring is 0.84 times of outer shroud radius;

Because the position of diffraction element has only two values mutually on all phase boards, 0 and π, just be called array 2 ring two-value positions and encircle light uniforming device mutually.

By the conclusion of diffraction optics angular spectrum as can be known:

Be located at and introduce an infinitely-great position photo that includes the light uniforming device structure on the z=0 plane, desirable Gaussian beam impinges upon on the light uniforming device.The transmittance function of light uniforming device is that (z): it is E (x, y, 0) that Gaussian beam sees through the light uniforming device light intensity to S for x, y, and discrete Fourier transformation obtains the angular spectrum F0 (fx, fy, 0) of incident light on diffraction screen through two-dimensional space.

$E(f_x,f_Y,0)=\underset{-\&infin;}{\overset{\&infin;}{\&Integral;}}\underset{-\&infin;}{\overset{\&infin;}{\&Integral;}}E(x,y,0)\exp [-\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="DEST\_PATH\_HSB00000008304100011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(f_{X}x+f_{Y}y)]\mathrm{dxdy}---\left(1\right)$

In (1), f _X, f _YBe spatial frequency, $f_X=\frac{\mathrm{\&alpha;}}{\mathrm{\&lambda;}},$ $f_Y=\frac{\mathrm{\&beta;}}{\mathrm{\&lambda;}}$ (α, β are wave vectors

With X-axis, the angle between the Y-axis).Incident light is propagated along the Z direction through behind the light uniforming device.At the Z=z place, the frequency spectrum E. of spatial frequency (fx, fy z) are:

$E(f_X,f_Y,z)=E(f_X,f_Y,0)\exp (\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="DEST\_PATH\_HSB00000008304100011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\sqrt{\frac{1}{{\mathrm{\&lambda;}}^2}-f_X^2-{\mathrm{<figure-callout\; id="2"\; label="f\; Y"\; filenames="DEST\_PATH\_HSB00000008304100011.png"\; state="\{\{state\}\}">f</figure-callout>}}_Y^{}}.z)---\left(3\right)$

In (3), f _Xf _YMust satisfy condition $f_{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="DEST\_PATH\_HSB00000008304100011.png"\; state="\{\{state\}\}">X</figure-callout>}}^2+{\mathrm{<figure-callout\; id="2"\; label="f\; Y"\; filenames="DEST\_PATH\_HSB00000008304100011.png"\; state="\{\{state\}\}">f</figure-callout>}}_Y^{}\&le;1/{\mathrm{\&lambda;}}^2,$ This formula shows that the effect of propagating the z of a segment distance has just changed the relative phase of each angular spectrum component.But work as ${\mathrm{<figure-callout\; id="2"\; label="f\; X"\; filenames="DEST\_PATH\_HSB00000008304100011.png"\; state="\{\{state\}\}">f</figure-callout>}}_X^{}+{\mathrm{<figure-callout\; id="2"\; label="f\; Y"\; filenames="DEST\_PATH\_HSB00000008304100011.png"\; state="\{\{state\}\}">f</figure-callout>}}_Y^{}>1/{\mathrm{\&lambda;}}^2$ The time, (fx, fy z) are the frequency spectrum E. of spatial frequency

E(f _X，f _Y，z)＝E(f _X，f _Y，0)exp(-μz) (4)

In (4), $\mathrm{\&mu;}=\frac{2\mathrm{\&pi;}}{\mathrm{\&lambda;}}\sqrt{{\left(\frac{x}{z}\right)}^2+{\left(\frac{y}{z}\right)}^2-1}.$

Because μ is an arithmetic number, these wave components increase decay rapidly because of propagation distance.(4) formula is done inverse Fourier transform, obtain light wave amplitude E (x, y, z)

$E(x,y,z)={\&Integral;}_{-\&infin;}^{\&infin;}{\&Integral;}_{-\&infin;}^{\&infin;}E(f_X,f_Y,0)\exp (\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="DEST\_PATH\_HSB00000008304100011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}\sqrt{\frac{1}{{\mathrm{\&lambda;}}^2}-f_X^2-{\mathrm{<figure-callout\; id="2"\; label="f\; Y"\; filenames="DEST\_PATH\_HSB00000008304100011.png"\; state="\{\{state\}\}">f</figure-callout>}}_Y^{}}.z)\exp \left[\mathrm{<figure-callout\; id="2"\; label="j"\; filenames="DEST\_PATH\_HSB00000008304100011.png"\; state="\{\{state\}\}">j</figure-callout>}2\mathrm{\&pi;}(f_{X}x+f_{Y}y)\right]d{f}_{X}d{f}_Y---\left(5\right)$

More than being common angular spectrum diffraction theory, also is that we simulate the theoretical foundation of light uniforming device along light path.Encircle light uniforming device mutually at array 2 ring positions, what need modification is exactly each transmittance function.

The present invention has provided array 2 and has encircled the design parameter that the position is encircled light uniforming device mutually.We have selected 10 * 10 array in Fig. 2, the selection of this array will be satisfied a principle: promptly the aperture of incident beam must be less than the amplitude of array, thereby can make incident beam to shine on the light uniforming device fully.Design parameter for each 2 ring position these diffraction element of phase cyclic group is as follows: the outgoing aperture of generally choosing laser instrument is as the radius of outer shroud, and the outgoing aperture of common lasers is the with a tight waist of the Gaussian beam sent.

Array of the present invention 2 ring positions encircle mutually light uniforming device in the application of reality shown in 7.The 1st, the collimation laser device, the 2nd, condenser lens, the 3rd, array of the present invention 2 ring positions are encircled light uniforming device mutually, and the 4th, the CCD photodetector.The light that sends from collimation laser 1 encircles light uniforming device 3 through condenser lens 2 mutually with array 2 ring positions, produces diffractogram on the focal plane of condenser lens 2.Such diffracted beam intensity distributes and can be detected and confirmed it by the ccd detector on the focal plane that is placed on condenser lens 24.

After experimental results show that adding designed array 2 ring positions encircles light uniforming device mutually, realized really Gaussian beam is for conversion into emergent light near the plane wave front light beam.This explanation the present invention can be used for beam shaping, microelectronics non-mask etching and other needs in the various light paths of plane wave front.

This making array provided by the invention 2 ring positions are encircled the method for light uniforming device mutually, utilize lsi technology technology and plane photoetching process technology to realize, specifically may further comprise the steps:

Step 1, utilize the electron-beam direct writing legal system to make mother matrix;

Step 2, master pattern is transferred on the optical glass that scribbles photoresist by the contact photolithography method;

Step 3, utilize the inductive couple plasma lithographic technique, will move on to pattern etch on the optical glass photoresist in optical glass.

Above-mentioned manufacturing girdle photon sieve utilizes lsi technology technology and plane photoetching process technology to realize.At first, utilize the electron-beam direct writing legal system to make mother matrix, by the contact photolithography method, master pattern has been transferred on the optical glass that scribbles photoresist.The photoresist that is adopted is Shipley s1818, and thickness is 1.8 μ m.The error of repelication of contact exposure is less than 0.5 μ m.Each parameter of girdle photon sieve provides in preamble.At last, utilize the inductive couple plasma lithographic technique, with pattern etch in optical glass.The etching gas that is adopted is fluoroform (CHF ₃), flow is 30SCCM, and RF power is 500W, and bias power is 200W, is 0.077 μ m/min to the etch rate of quartz substrate.Corresponding to 0.6328 mum wavelength, the refractive index of optical glass is 1.521, thereby the corresponding degree of depth in π position is 0.607 μ m.The degree of depth of utilizing Taylor's contourgraph to measure girdle photon sieve is 0.607 μ m.Light path synoptic diagram according to Fig. 7 arranges the measurement light path. and the laser works wavelength is 632.8nm.Expand bundle, collimation then.In experiment, be that 2 ring positions of one 10 * 10 array are encircled light uniforming device mutually, place ccd detector, the considerable thus size of measuring diffraction pattern then at the focal beam spot place.Measured data has proved the correctness of Theoretical Calculation.

Encircling light uniforming device mutually with one 10 * 10 array 2 ring positions below is example, describes its method for making:

1), determine optical maser wavelength and perforation hole radius, also be the outgoing beam waist radius;

2), determine the radius of the light beam of the wealthy Shu Yihou of laser according to need of work, the array that make must be greater than this radius.

3), according to the draw domain of light uniforming device of method as herein described.

4), make array 2 ring positions and encircle light uniforming device mutually.

Suppose that optical maser wavelength is 632.8 nanometers, the waist radius in laser emitting hole is 32 microns.The radius of drawing together the Shu Yihou Gaussian beam is 180 microns, selects 10 * 10 array, can satisfy whole requirements.Each 2 ring position outer shroud radius of ring mutually are 32 microns, and interior ring radius is 32 * 0.84=26.88 micron.Wherein the outer shroud position is 0 mutually, does not need etching; Interior ring position is 0.607 μ m for the corresponding etching depth of π mutually.Lighttight part all plates chromium.

Above-described concrete embodiment has carried out further detailed explanation to purpose of the present invention, technical scheme and beneficial effect.Institute it should be understood that the above only for concrete embodiment of the present invention, is not limited to the present invention.All any modifications of being made within the spirit and principles in the present invention, be equal to and replace or improvement etc., all should be included within protection scope of the present invention.

Claims (6)

1. array 2 ring positions are encircled light uniforming device mutually, it is characterized in that, it is a kind of 2 ring positions of making on transparent medium arrays of ring mutually that this 2 ring position is encircled light uniforming device mutually, the size of array is provided by actual needs, the size of array selects to want to make the light beam of incident be held by array fully that this 2 ring position ring mutually is the elementary cell of array.

2. array according to claim 12 ring positions are encircled light uniforming device mutually, it is characterized in that, this 2 ring position ring mutually is the position photo of a twin nuclei, and the real radius of outer shroud is provided by actual needs, and the real radius of interior ring is 0.84 times of outer shroud radius.

3. array according to claim 12 ring positions are encircled light uniforming device mutually, it is characterized in that, in this 2 ring position was encircled mutually, interior endless belt position was π mutually, and outer endless belt position is 0 mutually, and remainder is light tight; Perhaps interior endless belt position is 0 mutually, and outer endless belt position is π mutually, and remainder is light tight.

4. make the method that array 2 ring positions are encircled light uniforming device mutually for one kind, it is characterized in that this method utilizes lsi technology technology and plane photoetching process technology to realize, comprising:

Utilize the electron-beam direct writing legal system to make mother matrix;

Master pattern is transferred on the optical glass that scribbles photoresist by the contact photolithography method;

Utilize the inductive couple plasma lithographic technique, will move on to pattern etch on the optical glass photoresist in optical glass.

5. making array according to claim 42 ring positions are encircled the method for light uniforming device mutually, it is characterized in that, describedly master pattern is transferred in the step on the optical glass that scribbles photoresist by the contact photolithography method, the error of repelication of described contact exposure is less than 0.5 μ m, the photoresist that is adopted is Shipley s1818, and thickness is 1.8 μ m.

6. making array according to claim 42 ring positions are encircled the method for light uniforming device mutually, it is characterized in that, in the described step of pattern etch in the optical glass that will move on on the optical glass photoresist, the etching gas that is adopted is fluoroform CHF ₃, flow is 30SCCM, and RF power is 500W, and bias power is 200W, is 0.077 μ m/min to the etch rate of quartz substrate.

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