KR100903657B1 - Line beam generator and manufacturing process of the same - Google Patents

Abstract

A line beam generator is disclosed. The line beam generator according to the embodiment of the present invention includes a beam incidence portion to which the beam in the first direction is incident; A multi-mirror part disposed inclined at a first angle with respect to the beam incident part and in parallel with each other, in which N mirrors are in close contact with each other, wherein the mirror has a reflecting surface for reflecting or transmitting a beam on an upper side and a lower side; And a beam output part that is output in a second direction by the mirrors and has a cross section having an inclination of a second angle with respect to the mirrors of the multi-mirror part. The uniformity of the line beam and the light efficiency can be increased.

Line beam, mirror, reflection, uniform beam

Description

LINE BEAM GENERATOR AND MANUFACTURING PROCESS OF THE SAME}

The present invention relates to a line beam generator and more particularly to a line beam generator using multiple reflections.

There are various ways to make existing line beam. Such methods include truncation, flat-top, optical fiber, and the beam split into several to properly arrange the optical fiber, and the light source in one dimension. There are various methods, such as an array method and a lens array method such as an FEL (Fly Eye Lens) array.

Truncation is a method of enlarging a beam and cutting only a beam having a predetermined uniformity or more. In addition, the flat-top method refers to a method of uniformizing a beam by using an aspherical lens such as a powell lens, a hologram optical element (HOE), or a diffractive optical element (DOE).

The truncation method has a trade-off relationship in which efficiency decreases to increase uniformity and decreases uniformity to increase efficiency. Therefore, both uniformity and efficiency cannot be raised at the same time. In addition, the flat top method using an aspherical lens such as a Powell lens is not easy to manufacture the lens, and there is a difficulty that the distance between the lenses must be secured over a certain distance. In addition, according to the flat top method, the manufacturing process becomes difficult because the process error increases according to the width of the incident beam or the degree of collimation.

The HOE device or the DOE device is inferior in fabrication performance and efficiency, and the emission angles of the emitted beams are not parallel to each other, so that the uniformity is inferior when the designed distance is out of range. The use of optical fibers is not suitable for line illumination that requires the width of the light to be kept small, since the width is increased after the light passes through the fiber.

In addition, a method of arranging light sources in one dimension or a method such as a fly eye lens (FEL) has a complicated optical system and a long optical path.

The present invention seeks to provide a line beam generator that is easy to adjust by employing a multiple reflection mirror scheme in which the optical system is simple and insensitive.

It is another object of the present invention to provide a line beam generator for generating a uniform line beam.

In addition, the present invention is to provide a line beam generator that can reduce the length of the optical system.

In addition, the present invention is to provide a line beam generator that can obtain a line beam with low coherence by adjusting the distance between the output beams.

In addition, the distance difference between the reflected light is longer than the interference distance of the light source to combine a number of non-interfering beams, as a result to provide a line beam generator that can reduce the speckle.

In addition, the present invention is to provide a line beam generator that can obtain a uniformity of the line beam while also increasing the light efficiency.

Other objects of the present invention will become more apparent through the preferred embodiments described below.

According to an aspect of the present invention, the beam incidence portion to which the beam in the first direction is incident; A multi-mirror part disposed inclined at a first angle with respect to the beam incident part and in parallel with each other, in which N mirrors are in close contact with each other, wherein the mirror has a reflecting surface for reflecting or transmitting a beam on an upper side and a lower side; And a beam output unit having an output beam emitted by the mirrors in a second direction and having a second angle of inclination with respect to the mirrors of the multi-mirror unit.

Here, the sum of the first angle and the second angle may be 90 degrees.

Here, the upper side may reflect the beam incident in the first direction in the second direction, and the lower side may reflect the beam incident in the second direction in the first direction.

Here, the upper side reflects a part of the beam incident in the first direction in the second direction and transmits the rest in the first direction, and the lower side transmits a part of the beam incident in the second direction. It can reflect in one direction and transmit the rest in the second direction.

The multiple mirror unit may include three or more mirrors.

In addition, the mirror included in the multi-mirror unit may be arranged to overlap four or more mirrors in the second direction when viewed from the beam output unit.

The k th mirror among the mirrors may include any one of a beam transmitted in the first direction from the k-1 th mirror or a beam incident in the first direction from the beam incidence portion, and a k + 1 th mirror. A beam reflected in the second direction may be incident, where k is greater than or equal to 1 and less than N.

The k th mirror may include a portion of one of the beams transmitted in the first direction from the k-1 th mirror or the beams incident in the first direction from the beam incidence part in the second direction. Reflecting and transmitting the remaining part in the first direction, and transmitting a part of the beam reflected from the k + 1th mirror in the second direction in the second direction and reflecting the remaining part in the first direction. Where k is greater than 1 and less than N.

In addition, a first mirror of the mirrors reflects a part of the beam incident from the beam incident part in the first direction in the second direction and transmits the remaining part in the first direction, and is reflected from the second mirror to reflect the A part of the beam incident in the second direction may be transmitted in the second direction and the other part may be reflected in the first direction.

The N th mirror among the mirrors may reflect all the beams transmitted from the N-1 th mirror in the first direction in the second direction.

The reflectance of the k th mirror among the mirrors is greater than or equal to that of the k-1 th mirror.

Here, the beam incidence part is a cross-section cut inclined with respect to the stacking direction of the mirrors formed by stacking the N mirrors, and is included in a plane crossing the beam incident in the first direction.

In addition, the beam incident part may be antireflective coated.

Here, the beam output part is a cross-section cut inclined with respect to the stacking direction of the mirrors formed by stacking the N mirrors, and is included in a plane that crosses the beam emitted in the second direction.

Wherein the beam output is antireflective coated.

Here, the thickness of the mirrors may be adjusted to reduce the interference between the output beams.

Here, the mirrors are arranged in a line so that the output beams are emitted in a line to form a line beam, and the angles of the mirrors are adjustable.

In addition, the intensity of the output beams may be uniform.

The angle of incidence of the beams on the mirrors is greater than or equal to 40 degrees and less than or equal to 50 degrees.

In addition, according to another aspect of the present invention (a) stacking a plurality of mirrors to form a laminated mirror; (b) cutting an upper end of the laminated mirror to form a first cross section including M mirror layers and inclined at a first angle with respect to a stacking direction of the mirrors; (c) cutting one side of the laminated mirror to form a second cross section including N mirror layers and inclined at a second angle with respect to the stacking direction; And (d) antireflective coating treatment of the first and second cross-sections.

The mirror reflects a part of the beam incident in the first direction in the second direction and transmits the rest in the first direction, and reflects a part of the beam incident in the second direction in the first direction. The rest can be transmitted in the second direction.

Wherein step (a) is characterized in that for stacking the mirrors to sequentially increase the reflectance.

The method may further include adjusting the N value by cutting the lower end of the laminated mirror into a plane parallel to the first cross section.

The method may further include adjusting (M) the M value by cutting another side of the laminated mirror in parallel with the second cross section.

As described above, according to the embodiment of the present invention, the optical system adopts a simple and insensitive multiple reflection mirror method, thereby providing a line beam generator that is easy to adjust.

In addition, according to an embodiment of the present invention can provide a line beam generator for generating a uniform line beam.

In addition, according to an embodiment of the present invention can provide a line beam generator that can reduce the length of the optical system.

In addition, according to an embodiment of the present invention it is possible to provide a line beam generator that can obtain a line beam with low coherence by adjusting the distance between the output beams.

In addition, according to an embodiment of the present invention by increasing the distance difference between the reflected light than the interference distance of the light source, it is possible to provide a line beam generator that can combine a number of non-interfering beams, as a result can reduce the speckle.

In addition, according to an embodiment of the present invention can provide a line beam generator that can obtain a uniformity of the line beam while also increasing the light efficiency.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

The term and / or includes a combination of a plurality of related items or any item of a plurality of related items. The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In this application, the terms "comprising" or "mounted" and "mounted" are intended to indicate that there is a feature, number, step, action, component, part, or combination thereof described on the specification, one Or other features or numbers, steps, operations, components, parts or combinations thereof in any way should not be excluded in advance.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and shall not be construed in ideal or excessively formal meanings unless expressly defined in this application. Do not.

Other aspects, features, and advantages other than those described above will become apparent from the following drawings, claims, and detailed description of the invention.

Hereinafter, embodiments of the line beam generator according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a line beam generator according to an embodiment of the present invention.

Referring to FIG. 1, a line beam generator according to an embodiment of the present invention includes a beam incidence unit 110, a multiple mirror unit 120, and a beam output unit 130.

The multiple mirror unit 120 may include a plurality (N) mirrors 120-1, 120-2, 120-3,..., 120 -N, and these mirrors are arranged in parallel with each other. Mirrors 120-1, 120-2, 120-3, ... 120-N are reflective surfaces (the surfaces outside the mirror where actual reflections occur), and layers of a certain thickness between the reflective surfaces and the reflective surfaces (such as layers, glass plates, etc.). It can be composed of). In other words, the reflecting surface constitutes both surfaces of the mirror. Herein, the reflective surface provided above the mirror will be referred to as an upper side, and the reflective surface provided below the mirror will be referred to as a lower side.

In addition, the mirrors 120-1, 120-2, 120-3,..., 120 -N may be bonded or adhered to each other.

Accordingly, the multi-mirror unit 120 may be formed by the lower side of the k-1 th mirror, the upper side of the k th mirror, the lower side of the k th mirror, and the upper side of the k + 1 th mirror join each other. . Where k is a natural number greater than 1 and less than N.

In the embodiment according to FIG. 1, it is assumed that the beam is incident perpendicularly to the beam incident part 110.

That is, according to the embodiment shown in Figure 1, the beam is incident perpendicularly to the beam incident portion 110, the mirrors 120-1, 120-2, 120-3, ... 120 of the multiple mirror portion 120 -N) is incident at an angle of about 45 degrees. That is, the mirrors 120-1, 120-2, 120-3,... 120 -N of the multiple mirror unit 120 are inclined with respect to the beam incident part 110.

The direction in which the beam is incident on the mirror is called a first direction. The angle of incidence or reflection of the beam relative to the mirrors 120-1, 120-2, 120-3, ... 120-N is not limited to 45 degrees. The beam may be incident on the mirrors 120-1, 120-2, 120-3,... 120 -N at an angle of incidence of 40 degrees to 50 degrees. According to another embodiment, the angle of incidence of the beams to the mirrors 120-1, 120-2, 120-3,... 120 -N may have another value.

As shown in FIG. 1, the multiple mirror unit 120 may include three or more mirrors. In the present specification, a case in which the multiple mirror unit includes three or more mirrors will be described as an example. Here, the number of mirrors in the horizontal direction through which any beam passes through the multi-mirror portion 120 by the method of reflection and / or transmission is referred to as the degree of interplanar overlap. That is, the degree of overlap between planes has a value equal to the number of mirrors that reflect and / or transmit a beam among mirrors overlapping in the horizontal direction. Accordingly, the degree of overlap between the surfaces of the multiple mirrors 120 according to the embodiment shown in FIG. 1 is four.

Mirrors 120-1, 120-2, 120-3, ... 120-N reflect part of the incident beam and transmit part of it. While the beam is reflected from the mirror, the traveling direction is changed. The direction of travel after the beam traveling in the first direction is reflected is called a second direction. In this case, the reflectance or transmittance of the mirrors 120-1, 120-2, 120-3,..., 120 -N may be adjusted differently. That is, when the reflectance of the first mirror 120-1 is r ₁ and the reflectance of the second mirror 120-2 is r ₂ , r ₁ and r ₂ may have different values.

When the first direction is any one of a vertical or horizontal direction, according to an embodiment, the second direction may be the other direction of the horizontal or vertical direction. However, according to another embodiment, the first direction and the second direction are not necessarily perpendicular.

2 illustrates a process of forming a multi-mirror unit 120 by stacking mirrors and forming a beam incidence unit 110 and a beam output unit 130 from the stacked mirrors according to an embodiment of the present invention. Do it.

In addition, when the degree of overlap between the planes is 2 or more, it is necessary to divide the multiple mirror units 120 by cell to explain the incident and exit of the beam. When the multiple mirror unit 120 is arbitrarily divided and one divided part is referred to as one cell, one cell 600 among the cells constituting the multiple mirror unit 120 may be described as an example. Incident, reflection and transmission of the beam in one cell 600 will be described with reference to FIG. 6.

2 to 4 are views illustrating a process of forming the laminated mirror, the beam incident part 110 and the beam output part 130 according to an embodiment of the present invention.

FIG. 2 is a view illustrating stacks of mirrors 120-1, 120-2,..., 120 -N, 120 -N + 1, 120 -N + 2,.

The laminated mirror may include a plurality (N or more) mirrors 120-1, 120-2, 120-3, ... 120-N, 120-N + 1, 120-N + 2, ... These mirrors can be arranged parallel to each other. According to the exemplary embodiment shown in FIG. 2, the mirrors 120-1, 120-2, 120-3,..., May be bonded to or close to each other.

Alternatively, the stacked mirror 300 includes N mirrors, and the mirror (first mirror 120-1 or N-th mirror 120-N located at the lowermost or uppermost end in consideration of the mirror being cut off by an inclined cutting). The thickness of)) can be thicker than other mirrors.

That is, the lower side of the first mirror and the upper side of the second mirror, and the lower side of the second mirror and the upper side of the third mirror are joined to each other. By the same method, the upper side up to the N th mirror is bonded to the lower side of the N-1 th mirror so that the first mirror 120-1 to the N th mirror 120-N can be stacked to form a laminated mirror. .

3 illustrates a laminated mirror 300 formed by the process of FIG. 2. In addition, FIG. 4 illustrates that the multilayer mirror 300 of FIG. 3 is cut in a predetermined direction so that the multi-mirror unit 120 of the line beam generator according to the exemplary embodiment of the present invention, as well as the beam incident unit 110 and the beam output unit ( 130 is generated.

3 and 4, the line beam generator according to the exemplary embodiment of the present invention may be formed by cutting the stacked mirror 300.

The stacking mirror 300 illustrated in FIG. 3 is formed by stacking the mirrors 120-1, 120-2,. 3, the stacking direction 310, which is a direction in which the mirrors 120-1, 120-2,..., Are stacked in parallel, may be a vertical direction.

Each mirror may have the same thickness Th. In addition, the reflectivity may increase little by little from the first mirror to the Nth mirror. Of course, the increase in reflectance can be very small. There may also be mirrors having the same reflectivity.

(r ₁ ≤ r ₂ ≤ r ₃ ... ≤ r _k ≤ ... ≤ r _N )

Here, the refractive index of the first mirror 120-1 is n ₁ , the refractive index of the second mirror 120-2 is n ₂ , and the refractive index of the k-th mirror is referred to as n _k .

Considering that beams are transmitted between the mirrors, when the mirrors are in close contact with each other, the k-1st mirror 120- (k-1) becomes the incident medium and the kth mirror 120-k becomes the transmission medium. . Also, in relation to the k + 1th mirror 120- (k + 1), the kth mirror 120-k is an incident medium, and the k + 1th mirror 120- (k + 1) is a transmission medium.

Each of the mirrors 120-1, 120-2,..., May have different refractive indices and reflectances depending on how the mirrors are coated. According to one embodiment, the coating condition of the mirror is that the optical properties such as the refractive index of the incident medium and the transmission medium are the same or similar when a beam of the same wavelength is incident at a certain angle (for example 45 degrees).

Herein, if the refractive index of the incident medium is n _k-1 and the refractive index of the transmission medium is n _k , n _k-1 and n _k may satisfy the following equation.

-0.5 ≤ Δn ≤ 0.5 (n _k-1 -n _k = Δn)

The refractive index of the incident medium and the refractive index of the transmission medium may be the same, but are not limited thereto. However, even when the refractive index of the incident medium and that of the transmission medium are different from each other, the difference Δn may be limited to a predetermined value or less. This is because when the refractive indices between adjacent mirrors are drastically different, the beam propagating in the multi-mirror unit 120 is bent, thereby deviating from the traveling path. That is, the path of the beams needs to be adjusted to minimize the coherence between the beams, and the path of the beams may be adjusted according to the refractive index of the mirrors or the difference Δn of the refractive indices. By adjusting the reflectance (or transmittance) of the mirror, a uniform line beam can be generated. The reflectance and refractive index of the mirror will be described in more detail with reference to FIG. 8.

4 (a) shows a state in which the laminated mirror 300 is cut, Figure 4 (b) is a cut laminated mirror 300, a multi-mirror 120, a beam incident portion, a beam output portion formed Represents a line beam generator.

The beam incident part 110 is included in a plane (first plane 410) inclined with respect to the stacking direction 310 of the stacking mirror 300. According to an exemplary embodiment, the beam incident part 110 may be a cross section generated by cutting the laminated mirror 300 inclinedly.

The beam incidence 110 is included in the first plane 410 lying in the direction of the beam incident in the first direction 415 or the first direction 415. On the other hand, the beam output unit 130 is included in a beam (second plane, 420) lying in a direction crossing the second direction 425 or a beam incident in the second direction 425.

The beam output unit 130 is also included in the second plane 420 inclined with respect to the stacking direction 310 of the stacking mirror 300. According to an embodiment, the beam output unit 130 may be a cross section generated by cutting the laminated mirror 300 inclinedly.

Surfaces generated by cutting the laminated mirror 300 at an angle may be the beam incidence unit 110 and the beam output unit 130, respectively. The laminated mirror 300 may be cut inclined at four sides of the top, bottom, left and right, or four sides of the top, bottom, front and rear. Mirrors 120-1, 120-2, 120-3, ... 120-N, 120-N + 1, 120-N + 2, ... that were included in the laminated mirror 300 by the inclined cutting A portion of is cut off and only N or fewer mirrors 120-1, 120-2, 120-3, ... 120-N remain in the multiple mirror portion 120 (FIG. 4).

Alternatively, as shown in FIG. 2, a thick mirror may be used as the N-th mirror 120 -N of the laminated mirror 300. In this case, even if the lower end of the laminated mirror 300 is obliquely cut, the multiple mirrors 120 may still include N mirrors.

Here, the beam incident part 110 and the beam output part 130 may be subjected to an anti-reflective coating (AR coating) process. The antireflective coating is processed to ensure that the propagation of the incoming or exiting beam is not disturbed by reflection.

Hereinafter, an embodiment of a line beam generator having a degree of overlap between planes of FIG. 5 will be described.

5 is a diagram illustrating a line beam generator according to another embodiment of the present invention. According to the embodiment shown in FIG. 5, the multi-mirror unit 500 includes a plurality of mirrors, but the beam 510 incident through the beam incidence unit 515 is incident only to the first mirror of the multi-mirror unit 500. Are reflected and transmitted. Thus, P ₁ 520 is not zero (P ₁ ≠ 0), but P ₂ , P ₃ and P ₄ are zero (P ₂ = P ₃ = P ₄ = 0). Accordingly, according to the definition of the degree of overlap between planes according to the description of FIG. 1, the degree of overlap between planes of the line beam generator illustrated in FIG. 5 is 1.

An incident beam 520 with a beam intensity of P ₁ is incident through the beam incidence 515 with high transmittance due to the antireflective coating. When the beam intensity reflected through the first mirror M ₁ having the reflectance r ₁ and emitted is T ₁ , T ₁ = P ₁ × r ₁ is satisfied.

When reflectance hayeoteul reached the mirror M ₁ r ₁ of the beam the reflectance r ₂ of the second mirror M ₂ is transmitted through, the intensity of the beam is _{P 1 × (1-r 1} -a).

Therefore, the intensity T ₂ of the beam reflected from the second mirror M ₂ and emitted is as follows.

T ₂ = P ₁ × (1-r ₁ -a) × r ₂ = P ₁ × t ₁ × r ₂

Where t _i = 1-r _i -a, where a is the loss rate of the beam due to absorption or scattering.

Similarly, the intensity of the beam reflected off M ₃

T ₃ = P ₁ × t ₁ × t ₂ × r ₃ .

Generalizing this, if the intensities of the emission beams 540 emitted through the N-1, N-th mirrors M _N-1 and M _N are T _N-1 and T _N , respectively, the following equations are established.

T _N-1 = P ₁ × t ₁ × t ₂ ×. × t _N-2 × r _N-1

T _N = P ₁ × t ₁ × t ₂ ×. × t _N-2 × t _N-1 × r _N

And T ₁ = T ₂ =... The reflectance conditions of each mirror to be = T _N-1 = T _N are as follows.

r _N-1 = t _N-1 × r _N → r _N-1 = (1-r _N-1 -a) × r _N

If the loss ratio a of the beam is 0, 1 / r _N = 1 / (r _N-1 ) -1 is established.

Conditions for increasing light efficiency (; ∑T _N = T ₁ + T ₂ +… + T _N = ~ P ₁ ) and uniform beam intensity conditions (; T ₁ = T ₂ =… = T _N ≒ P ₁ / N ), The following equation can be obtained.

r ₁ = 1 / N

r ₂ = 1 / (N −1)...

Here, the reflectance r _N of the N th mirror 530 may be 1 or a value close to 1. As a result, a uniform line illumination beam 550 can be obtained and the light efficiency can be improved.

FIG. 6 shows an arbitrary cell 600 of the mirror of the line beam generator shown in FIG. 1.

When the cell 600 illustrated in FIG. 6 is located in the i-th column and the j-th row of the multiple mirror unit 120 of FIG. 1, the coordinates of the cell 600 become (i, j). The portion of the mirror corresponding to cell 600 is denoted M (i, j). Mirror M (i, j) is included in the k-th mirror.

i is determined by the number of columns from which the cell is located (130 in FIG. 1), and j is determined by the number of rows from the beam incidence (110 in FIG. 1). The reflectance of M (i, j) is called r _{i, j} . It is also assumed that M (i, j) is included in the k th mirror in the multiple mirror unit 120 of FIG.

The beam in the vertical direction incident on M (i, j) is a beam transmitted from the mirror M (i, j-1) of the cell having the coordinates of (i, j-1), and V _{i, j− It} is indicated by ₁ . Mirror M (i, j-1) is included in the k-1 th mirror. V _{i, j-1} is incident on the upper side of M (i, j). The horizontal beam incident on M (i, j) is a beam emitted from the mirror M (i + 1, j) of a cell having coordinates of (i + 1, j), and H _{i + 1, It} is represented by _j . H _{i + 1, j} is incident on the lower surface of M (i, j).

In addition, horizontal beams emitted from M (i, j) are H _{i, j} , and H _{i + 1, j} transmitted through M (i, j), and V _{i, j-1} are M (i , j) is the sum of the beams reflected from the upper side of j). And M beams in the vertical direction that is emitted from the (i, j) is V _i, a _j, V _{i, j-1} is M (i, j) to the transmitted beam _and, H _{i + 1, j} beam through M It is the sum of the beams reflected from the lower side of (i, j).

In FIG. 6, an example in which reflectances of the upper and lower surfaces of M (i, j) are the same as r _{i, j} will be described. In this case, the transmittances of the upper and lower surfaces of M (i, j) are (1-r _{i, j} ).

H _{i, j,} which is a beam emitted in the horizontal direction from M (i, j) _, and V _{i, j, which} is a beam emitted in the vertical direction, satisfy the following equation.

However, when j is 1, i.e., V _{i, j-1} = P _i . As illustrated in FIG. 4, P _i is a beam that is first incident to the multiple mirrors through the beam incidence unit and does not pass through the mirror, and means a unit beam incident to the i-th mirror. For example, P ₁ refers to a unit beam that is incident to a beam incident part close to the beam output part and is reflected and transmitted by the first mirror of the multiple mirror part. P ₂ also means a unit beam in which the first incident mirror is the second mirror.

A horizontal beam emitted from the mirror M (i, j) of an arbitrary cell is expressed as follows.

H _{i, j} = (1- r _{i, j} ) × H _{i + 1, j} + r _{i, j} × V _{i, j-1}

H _{i, 1} = (1- r _{i, 1} ) × H _{i + 1,1} + r _{i, 1} × P _i (if j = 1)

In addition, a vertical beam emitted from the mirror M (i, j) of an arbitrary cell is represented by the following equation.

V _{i, j} = r _{i, j} × H _{i + 1, j} + (1- r _{i, j} ) × V _{i, j-1}

V _{i, 1} = r _{i, 1} × H _{i + 1,1} + (1- r _{i, 1} ) × P _i, (if j = 1)

If the beam V _{i, j} in the vertical direction and the beam H _{i, j in the} horizontal direction satisfy the above formula in any cell, even if the incident beam has the form of a Gaussian beam or any non-uniform distribution Uniform illumination beams can be made.

7 is a diagram illustrating a line beam generator according to an embodiment of the present invention.

When the thickness of the multi-mirror portion and the length in the vertical direction are d and l, respectively, the width of the unit incident beam is called w. The unit incident beams 720, P ₁ , P ₂ , P ₃ , and P ₄ may be beams obtained by dividing the incident beam 710 by an overlap between planes. In FIG. 7, the degree of overlap between planes is 4, and accordingly, the incident beam 720 is divided into four unit beams 720. When the degree of overlap between planes M is M≥2, P ₁ ≠ P ₂ ≠ P ₃ ≠. ≠ P _M ≠ 0. And the following equation can be derived.

l = N × w,

w = d / M

Here, in the line beam generator in which the mirrors are stacked and bonded as shown in FIGS. 2 to 4, the first direction in which the beam is incident and the second direction in which the beam is emitted are perpendicular, and the angle of incidence of the beam with respect to the mirrors is perpendicular. (Or reflection angle) may be 45 degrees. In this case, the thickness Th of the mirror and w, which is the width of the unit incident beam, may be in the following relationship.

Referring to FIG. 7, one of the cells constituting the multiple mirror unit 700 of the line beam generator may be the cell 600 illustrated in FIG. 1.

As shown in Fig. 7, when the overlapping degree M between planes is M = 4, i = 1,2,3,4, and j is j = 1. It is a positive integer equal to N. here,

If i> M the intensity of beam H _{i, j} incident on plane r _i-1 = 0

If i = 1 _, the intensity of the beam _{Hi, j} emitted from the surface r _i = T _j .

If j = 1, then V _{i, 1} = P _i , V _{i, 1} = P ₁ , V _2,1 = P ₂ , V _3,1 = P ₃ , V _4,1 = P ₄ . The incident beam is divided into unit beams and has a beam width of w.

Where j = 1, 2, 3, 4, 5,... In the case of N-2, N-1, N, the equation for obtaining the intensity of the beam emitted from each cell is as follows.

TABLE 1

j = 1 j = 2 H _1,1 = (1- r _1,1 ) × H _2,1 + r _1,1 × P ₁ V _1,1 = r _1,1 × H _2,1 + (1- r _1,1 ) × P ₁ H _2,1 = (1- r _2,1 ) × H _3,1 + r _2,1 × P ₂ V _2,1 = r _2,1 × H _3,1 + (1- r _2,1 ) × P ₂ H _3,1 = (1- r _3,1 ) × H _4,1 + r _3,1 × P ₃ V _3,1 = r _3,1 × H _4,1 + (1- r _{3 , 1} ) × P ₃ H _4,1 = (1- r _4,1 ) × H _5,1 + r _4,1 × P ₄ V _4,1 = r _4,1 × H _5,1 + (1- r _4,1 ) × P ₄ H _1,2 = (1- r _1,2 ) × H _2,2 + r _1,2 × V _1,1 V _1,2 = r _1,2 × H _2,2 + (1- r _1,2 ) × V _1,1 H _2,2 = (1- r _2,2 ) × H _3,2 + r _2,2 × V _2,1 V _2,2 = r _2,2 × H _3,2 + ( 1- r _2,2 ) × V _2,1 H _3,2 = (1- r _3,2 ) × H _4,2 + r _3,2 × V _3,1 V _3,2 = r _3,2 × H _4,2 + (1- r _3,2 ) × V _3,1 H _4,2 = (1- r _4,2 ) × H _5,2 + r _4,2 × V _4,1 V _4,2 = r _4,2 × H _5,2 + (1- r _4,2 ) × V _4,1

TABLE 2

j = 3 j = 4 H _1,3 = (1- r _1,3 ) × H _2,3 + r _1,3 × V _1,2 V _1,3 = r _1,3 × H _2,3 + (1- r _1,3 ) × V _1,2 H _2,3 = (1- r _2,3 ) × H _3,3 + r _2,3 × V _2,2 V _2,3 = r _2,3 × H _3,3 + (1- r _2,3 ) × V _2,2 H _3,3 = (1- r _3,3 ) × H _4,3 + r _3,3 × V _3,2 V _3,3 = r _3,3 × H _4,3 + (1- r _3,3 ) × V _3,2 H _4,3 = (1- r _4,3 ) × H _5,3 + r _4,3 × V _3,2 V _4,3 = r _4,3 × H _5,3 + (1- r _4,3 ) × V _3,2 H _1,4 = (1- r _1,4 ) × H _2,4 + r _1,4 × V _1,3 V _1,4 = r _1,4 × H _2,4 + (1- r _1,4 ) × V _1,3 H _2,4 = (1- r _2,4 ) × H _3,4 + r _2,4 × V _2,3 V _2,4 = r _2,4 × H _3,4 + (1- r _2,4 ) × V _2,3 H _3,4 = (1- r _3,4 ) × H _4,4 + r _3,4 × V _3,3 V _3,4 = r _3,4 × H _4,4 + (1- r _3,4 ) × V _3,3 H _4,4 = (1- r _4,4 ) × H _5,4 + r _3,4 × V _3,3 V _4,4 = r _4,4 × H _5,4 + (1- r _4,4 ) × V _3,3

TABLE 3

j = 5 j = N-2 H _1,5 = (1- r _1,5 ) × H _2,1 + r _1,5 × V _1,4 V _1,5 = r _1,5 × H _2,1 + (1- r _1,5 ) × V _1,4 H _2,5 = (1- r _2,5 ) × H _3,1 + r _2,5 × V _2,4 V _2,5 = r _2,5 × H _3,5 + (1- r _2,5 ) × V _2,4 H _3,5 = (1- r _3,5 ) × H _4,1 + r _3,5 × V _3,4 V _3,5 = r _3,1 × H _4,5 + (1- r _3,5 ) × V _3,4 H _4,5 = (1- r _4,5 ) × H _5,5 + r _4,5 × V _3,4 V _4,5 = r _4,5 × H _5,5 + (1- r _4,5 ) × V _3,4 H _{1, N-2} = (1-r _{1, N-2} ) × H _{2, N-2} + r _{1, N-2} × V _{1, N-3} V _{1, N-2} = r _{1, N- 2} x H _{2, N-2} + (1-r _{1, N-2} ) × V _{1, N-3} H _{2, N-2} = (1-r _{2, N-2} ) × H _{3, N-2} + r _{2, N-2} × V _{2, N-3} V _{2, N-2} = r _{2, N-2} × H _{3, N-2} + (1-r _{2, N-2} ) × V _{2, N -3} H _{3, N-2} = (1-r _{3, N-2} ) × H _{4, N-2} + r _{3, N-2} × V _{3, N-3} V _{3, N-2} = r _{3, N-2} × H _{4, N-2} + (1-r _{3, N-2} ) × V _{3, N-3} H _{4, N-2} = (1-r _{4, N-2} ) × H _{5, N-2} + r _{4, N-2} × V _{3, N-3} V _{4, N-2} = r _{4, N-2} × H _{5, N -2} + (1-r _{4, N-2} ) × V _{3, N-3}

TABLE 4

j = N-1 j = N H _{1, N-1} = (1-r _{1, N-1} ) × H _{2, N-1} + r _{1, N-1} × V _{1, N-2} V _{1, N-1} = r _{1, N- 1} × H _{2, N-1} + (1-r _{1, N-1} ) × V _{1, N-2} H _{2, N-1} = (1-r _{2, N-1} ) × H _{3, N-1} + r _{2, N-1} × V _{2, N-2} V _{2, N-1} = r _{2, N-1} × H _{3, N-1} + (1-r _{2, N-1} ) × V _{2, N -2} H _{3, N-1} = (1-r _{3, N-1} ) × H _{4, N-1} + r _{3, N-1} × V _{3, N-2} V _{3, N-1} = r _{3, N-1} × H _{4, N-1} + (1-r _{3, N-1} ) × V _{3, N-2} H _{4, N-1} = (1-r _{4, N-1} ) × H _{5, N-1} + r _{3, N-1} × V _{3, N-2} V _{4, N-1} = r _{4, N-1} × H _{5, N -1} + (1-r _{4, N-1} ) × V _{3, N-2} H _{1, N} = (1- r _{1, N} ) × H _{2, N} + r _{1, N} × V _{1, N-1} V _{1, N} = r _{1, N} × H _{2, N} + (1- r _{1, N} ) × V _{1, N-1} H _{2, N} = (1- r _{2, N} ) × H _{3, N} + r _{2, N} × V _{2, N-1} V _{2, N} = r _{2, N} × H _{3, N} + (1- r _{2, N} ) × V _{2, N-1} H _{3, N} = (1- r _{3, N} ) × H _4,1 + r _{3, N} × V _{3, N-1} V _{3, N} = r _{3, N} × H _{4, N} + (1- r _{3, N} ) × V _{3, N-1} H _{4, N} = (1- r _{4, N} ) × H _{5, N} + r _{4, N} × V _{3, N-1} V _{4, N} = r _{4, N} × H _{5, N} + (1- r _{4, N} ) × V _{3, N-1}

In addition, the conditions for improving light efficiency are as follows.

T _N = T ₁ + T ₂ +... + T _N ≒ P ₁ + P ₂ + P ₃ + P ₄

r _{1, N} = r _{2, N-1} = r _{3, N-2} = r _{4, N-3} = r _N ≒ 1 (r _N is the reflectivity of the Nth mirror 730)

Accordingly, the conditional formula T ₁ = T ₂ =... To obtain the uniform intensity of the output beam 740. = T _N ≒ ∑ P _i / N = (P ₁ + P ₂ + P ₃ + P ₄ ) / N

H _1,1 = T ₁

= (1- r _1,1 ) × {(1- r _2,1 ) × {(1-r _3,1 ) × (r _4,1 × P ₃ ) + r _3,1 × P ₃ } + r _2,1 × P ₂ } + r _1,1 × P ₁

= (1- r _1,1 ) × (1- r _2,1 ) × (1- r _3,1 ) × r _4,1 × P ₄ + (1- r _1,1 ) × (1- r _{2 , 1} ) × r _3,1 × P ₃ + (1- r _1,1 ) × r _2,1 × P ₂ + r _1,1 × P ₁

= ∑ (P ₁ ~ P ₄ ) / N

Solving the initial conditions of H _1,1 = T ₁ and the above relations to obtain the reflectance for each layer of the multi-reflective mirror results in a uniform line illumination beam 750 with high light efficiency.

As the output beams 740 of FIG. 7 are arranged in a line, a line beam may be generated. The distance between the mirrors, the thickness of the mirror, the angle of the mirror, and the like can be adjusted in order to correct errors such as preventing the warping of the line beam or to increase the uniformity of the line beam.

In addition, the reflectance of the mirrors included in the multi-mirror unit according to an embodiment of the present invention can be adjusted. In the above-described embodiment, the case in which one mirror has the same reflectance or transmittance has been described.

However, according to another embodiment, the reflectance value may be different from each other even in one mirror according to each part of the mirror. That is, the mirror may have different reflectance for each cell. The reflectances r _{i and j} of the upper side or the lower side of M (i, j) may have different values according to the change of the i value and j value.

The reflectivity of one mirror can vary continuously or discontinuously. The site-specific (or cell-specific) reflectivity of the mirror may vary depending on the material or method of the partially reflective coating applied to the mirror.

8 is a three-dimensional view of a line beam generator according to an embodiment of the present invention.

In the description of FIG. 8, n denotes the refractive index of the medium through which the beam passes, and t denotes the thickness of the mirror (interlayer distance of the mirrors) appearing on the beam output unit 130. According to an exemplary embodiment in which the beam output unit 130 is formed by cutting the mirrors inclined in the stacking direction of the mirrors 120-1, 120-2,..., 120 -N after stacking the mirrors, the stacked mirror (300 of FIG. 3). It may be the distance from the upper side of the mirror 120-k to the upper side of the next mirror 120- (k + 1) as shown on the cut cross section (420 of FIG. 4).

In the embodiment shown in Fig. 8, the degree of overlap between planes of the line beam generator is M. The interlayer distance t and refractive index n between two adjacent mirrors can be adjusted.

When the incident beams P ₁ , P ₂ , P ₃ , and P ₄ are emitted in the form of H _1,1 , the refractive index n of the medium and t are adjusted as follows so that the optical path difference between adjacent mirrors is an odd multiple of 2π / M. Then, the phase difference of the overlapping beams may be generated, and as a result, the coherence of the beams may be inferior. Accordingly, the speckle of the output beam may be reduced.

(λ = wavelength, Δφ = optical path difference)

When the incident beams P ₁ , P ₂ , P ₃ , and P ₄ are emitted in the form of H ₁ , _1, the coherence between the beams may be inferior when the difference in the optical paths is longer than the interference distance of the light source. In this case, the output beam is the same as the sum of several non-interfering beams, thereby reducing the speckle of the output beams.

The output beam which maintains uniformity in the y-axis direction is output by the method mentioned above. The output beam may converge in the x-axis direction by the y-cylinder lens having the vertical axis (y-axis) as the center. A narrow and long line beam can then be generated.

The line beam generator according to the embodiment shown in FIG. 8 may have specifications as shown in Tables 5 and 6 (an embodiment in which N = 19 (l = 10.75)). This is merely one embodiment of the line beam generator, and of course does not limit the scope of the invention.

Here, the A surface represents the beam incidence unit 110 and the B surface represents the beam output unit 130. AR coating means an anti-reflection coating to improve the transmittance of the beam. d is the width of the multi-mirror 120 (thickness of the line beam generator), W is the width of the output unit 130 (width of the line beam generator), l is the width of the multi-mirror 120 Length.

In addition, the materials of the mirrors 120-1, 120-2, ..., 120-N of the multiple mirror unit 120 may be BK7 glass. The mirror according to the embodiment of the present invention may be made by applying a mirror coating such as a partial reflection coating, a total reflection coating or an antireflection coating on the BK7 glass.

That is, BK7 is a material used as a material of a lens or a prism, and is one of optical glasses to be multi-coated. According to another embodiment there is no limitation on the material of the mirror (120-1, 120-2, ..., 120-N). In Tables 5 to 8 below, r _k denotes a reflectance of the k th mirror. The incident angle of the beam refers to an angle at which the beam is incident on the mirrors 120-1, 120-2,..., 120 -N of the multiple mirror unit 120. The reference wavelength refers to the wavelength of the beam, and the reference wavelengths described in the table below are just one example.

TABLE 5

reflectivity(%) r ₁ 5.7 r ₂ 5.7 r ₃ 5.7 r ₄ 6.5 r ₅ 6.5 r ₆ 7.0 r ₇ 8.0 r ₈ 8.0 r ₉ 9.5 r ₁₀ 10.0 r ₁₁ 10.5 r ₁₂ 13.5 r ₁₃ 13.5 r ₁₄ 17 r ₁₅ 21 r ₁₆ 23 r ₁₇ 36 r ₁₈ 48 r ₁₉ 100

TABLE 6

Thickness (d) 2.263mm Width (W) 5 mm Length (l) 10.75 Material BK7 Reference wavelength 532 nm Incident angle of the beam 45 ± 5deg A / B side AR Coating

In addition, the line beam generator according to another embodiment may have the specifications shown in Table 7 and Table 8 (an embodiment in which N = 16 (l = 9.05)). Similarly, this is only one embodiment of the line beam generator, of course, does not limit the scope of the present invention.

TABLE 7

reflectivity(%) r ₁ 6.5 r ₂ 6.5 r ₃ 7.0 r ₄ 8.0 r ₅ 8.0 r ₆ 9.5 r ₇ 10.0 r ₈ 10.5 r ₉ 13.5 r ₁₀ 13.5 r ₁₁ 17 r ₁₂ 21 r ₁₃ 23 r ₁₄ 36 r ₁₅ 48 r ₁₆ 100

TABLE 8

Thickness (d) 2.263mm Width (W) 5 mm Length (l) 9.05 Material BK7 Reference wavelength 532 nm Incident angle of the beam 45 ± 5deg A / B side AR Coating

9 is a flowchart illustrating a method of manufacturing a line beam generator according to an embodiment of the present invention.

The line beam generator according to an embodiment of the present invention may be manufactured by stacking mirrors and cutting the stacked mirrors formed in a predetermined direction. The laminated mirror herein may be the laminated mirror 300 shown in FIG. 3.

First a plurality of mirrors are stacked (step 910), the mirrors may be parallel to each other. Thus, the mirrors can be stacked in a certain direction. This direction will be referred to as the stacking direction. The stacking direction may be the stacking direction 310 illustrated in FIG. 3.

The laminated mirror is cut into sections in two different directions, respectively. One cross section is referred to as a first cross section and the other cross section is referred to as a second cross section. First, the laminated mirror may be cut into a cross section inclined at a first angle with respect to the mirror stacking direction (step 920). This cross section is called a 1st cross section. The first cross section may be a cross section obtained by obliquely cutting the upper end of the mirror. The plane including the first cross section may be the first plane 410 illustrated in FIG. 4.

When a beam is incident from the light source, the beam is first incident through the first cross section. The first cross section may be the beam incident part 110 of FIGS. 1 and 8.

In addition, the laminated mirror may be cut into a cross section inclined at a second angle with respect to the stacking direction of the mirror (step 930). This cross section is referred to as a second cross section. The second cross section may be a cross section obtained by obliquely cutting one side of the mirror. The plane in which the second cross section is included may be the second plane 420 illustrated in FIG. 4.

When a beam is incident from the light source to the laminated mirror and the beams reflected and transmitted in the laminated mirror are emitted, the beam may be output through the second cross section. The second cross section may be the beam output unit 130 of FIGS. 1 and 8.

Here, the first cross section and the second cross section may be subjected to an antireflective coating treatment (steps 940 and 950). The antireflective coating is processed to prevent the path of travel of the beam from being changed by the reflection or loss of the beam when the beam is incident on the first cross section and when the beam is output through the second cross section.

When the laminated mirror is cut, a plurality of mirror layers may appear in the cross section. In the cut laminated mirror, the first cross section may include M mirror layers and the second cross section may include N mirror layers. Here, M value is the number when the mirror layer is counted in the first direction, and N value is the number when the mirror layer is counted in the second direction.

The M and N values are adjustable values. In cutting the lower end of the laminated mirror, the upper end of which is cut into the first end face, in a plane parallel to the first end face, the N value may be changed by changing the cutting position thereof. Similarly, in cutting the other side of the laminated mirror in which one side is cut into the second cross section into a plane parallel to the second cross section, the M value may also be changed by changing the cutting position thereof.

According to an embodiment of the present invention, each of the mirrors forming the laminated mirror may have the same thickness Th. In addition, the reflectivity may increase little by little from the first mirror to the Nth mirror. Of course, the increase in reflectance can be very small. There may also be mirrors having the same reflectivity.

Reflectivity of the mirrors is r ₁ , r ₂ , r ₃ , r _k ,. , r _N , may reflect the following relationship.

r ₁ ≤ r ₂ ≤ r ₃ . ≤ r _k ≤. ≤ r _N

Beams may be incident on the mirrors in a first direction and / or in a second direction. When the beam is incident on the mirror in the first direction, when the beam is reflected, the beam travels in the second direction, and when the beam is transmitted, the beam travels in the first direction. Similarly, when a beam is incident on the mirror in the second direction, the beam travels in the first direction when the beam is reflected, and in the second direction when the beam is transmitted. The mirror reflects some or all of the incident beam and transmits the rest.

The amount (or intensity) of the beam reflected and transmitted by each mirror may vary depending on the transmittance of each mirror. However, the N-th mirror may be a total reflection coating and may reflect all incident beams.

The above-described embodiments of the present invention are disclosed for the purpose of illustration, and those skilled in the art may make various modifications, changes, and additions within the spirit and scope of the present invention. Should be considered to be within the scope of the following claims.

1 is a cross-sectional view of a line beam generator according to an embodiment of the present invention.

2 is a view showing a state in which mirrors are stacked in accordance with an embodiment of the present invention.

3 is a view showing a laminated mirror formed by the process of FIG.

4 is a view showing a state in which a laminated mirror is cut and a multi-mirror portion, a beam incidence portion, and a beam output portion are formed according to an embodiment of the present invention.

5 illustrates a line beam generator in accordance with another embodiment of the present invention.

FIG. 6 shows an arbitrary cell of the mirror of the line beam generator shown in FIG. 1. FIG.

7 illustrates a line beam generator in accordance with an embodiment of the present invention.

8 is a three-dimensional view of a line beam generator according to an embodiment of the present invention.

9 is a flowchart illustrating a method of manufacturing a line beam generator according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

110: beam incident part

120: multiple mirror

120-N: Nth mirror

130: beam output unit

Claims (24)

A beam incident part to which the beam in the first direction is incident; The multi-mirror part disposed inclined at a first angle with respect to the beam incidence part and in parallel with each other, in which N mirrors are in close contact with each other. -; And Output beams are emitted in a second direction by the mirrors and includes a beam output section having a cross section having an inclination of a second angle with respect to the mirrors of the multi-mirror portion, The multi-mirror portion includes three or more mirrors, and the mirrors included in the multi-mirror portion is arranged to overlap four or more mirrors in the second direction when viewed from the beam output unit. The method of claim 1, And the sum of the first angle and the second angle is 90 degrees. The method of claim 1, The upper side reflects the beam incident in the first direction in the second direction, and the lower side reflects the beam incident in the second direction in the first direction. The method of claim 1, The upper side reflects a part of the beam incident in the first direction in the second direction and transmits the remainder in the first direction, and the lower side transmits a part of the beam incident in the second direction in the first direction. And reflect the remainder in the second direction. delete delete The method of claim 1, The k th mirror among the mirrors includes any one of a beam transmitted in the first direction from the k-1 th mirror or a beam incident in the first direction from the beam incidence portion, and from the k + 1 th mirror. A line beam generator, in which k is greater than or equal to 1 and less than N, characterized in that a beam reflected in a second direction is incident. The method of claim 1, The k th mirror among the mirrors reflects a part of one of the beams transmitted in the first direction from the k-1 th mirror or the beams incident in the first direction from the beam incident part in the second direction. And the other part is transmitted in the first direction, and a part of the beam reflected from the k + 1th mirror in the second direction is transmitted in the second direction, and the other part is reflected in the first direction. Line beam generator, where k is greater than 1 and less than N. The method of claim 1, A first mirror of the mirrors reflects a part of the beam incident from the beam incident part in the first direction in the second direction and transmits the remaining part in the first direction, and is reflected from a second mirror to reflect the first beam. And a part of the beam incident in two directions is transmitted in the second direction and the other part is reflected in the first direction. The method of claim 1, The Nth mirror of the mirrors, the line beam generator, characterized in that for reflecting all the beams transmitted from the N-1 th mirror in the first direction in the second direction. The method of claim 1, Wherein the reflectivity of the k th mirror among the mirrors is greater than or equal to the reflectivity of the k-1 th mirror, where k is greater than 1 and less than N. The method of claim 1, The beam incidence part is a cross-section of the multi-mirror part formed by stacking the N mirrors inclined with respect to the stacking direction of the mirrors, and is included in a plane crossing the beam incident in the first direction. Generator. The method according to any one of claims 1 to 12, And the beam incidence portion is antireflective coated. The method of claim 1, The beam output part is a cross-section cut inclined with respect to the stacking direction of the mirrors formed by stacking the N mirrors, and is included in a plane crossing the beam emitted in the second direction. Generator. The method according to any one of claims 1 to 14, And the beam output unit is antireflective coated. The method of claim 1, And the thickness of the mirrors is adjusted to reduce the coherence between the output beams. The method of claim 1, And the mirrors are arranged in a line so that the output beams are output in a line to form a line beam, and the angle of the mirrors is adjustable. The method according to any one of claims 1 to 17, And the intensity of the output beams is uniform. The method of claim 1, And the incident angle of the beams to the mirrors is greater than or equal to 40 degrees and less than or equal to 50 degrees. (a) stacking a plurality of mirrors to form a laminated mirror; (b) cutting an upper end of the laminated mirror to form a first cross section including M mirror layers and inclined at a first angle with respect to a stacking direction of the mirrors; (c) cutting one side of the laminated mirror to form a second cross section including N mirror layers and inclined at a second angle with respect to the stacking direction; (d) antireflective coating the first end face and the second end face; And (e) cutting the lower end of the laminated mirror into a plane parallel to the first cross section to adjust the N value, and cutting the other side of the laminated mirror parallel to the second cross section to adjust the M value. A line beam generator manufacturing method comprising the steps. The method of claim 20, The mirror reflects a portion of the beam incident in the first direction in the second direction and transmits the remainder in the first direction, and reflects a portion of the beam incident in the second direction in the first direction and the rest. And transmitting the beam in the second direction. The method of claim 20, And the step (a) sequentially stacks the mirrors to increase the reflectance. delete delete

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