KR102374014B1 - A making device and method of holographic screen for projecting 3d image - Google Patents

Abstract

The present invention relates to a three-dimensional image projection holographic screen that can easily and inexpensively produce three-dimensional image projection screens of various sizes without using optical components such as spherical reflectors or lenses. It relates to a manufacturing apparatus and a manufacturing method.
The present invention provides an apparatus for manufacturing a holographic screen for 3D image projection, comprising: a flat plate on which a photosensitive plate having a photosensitive emulsion applied on one surface is laminated; a diffusion plate laminated on the photosensitive plate to improve the surface uniformity of the holographic screen and expand the viewing area; a transparent plate on which a diffraction pattern or a Fresnel pattern generated by calculation is printed; and a light source for illuminating the expanded beam toward the transparent plate.

Description

A MAKING DEVICE AND METHOD OF HOLOGRAPHIC SCREEN FOR PROJECTING 3D IMAGE

The present invention relates to an apparatus and method for manufacturing a holographic screen for three-dimensional image projection, and in detail, a three-dimensional image projection screen of various sizes without using optical components such as a spherical reflector or a lens. To a manufacturing apparatus and manufacturing method of a holographic screen for 3D image projection, which can be manufactured simply and inexpensively in a short time.

In a display screen capable of simultaneously projecting three-dimensional images including flat, holographic reproduction images and volumetric images, the image displayed by focusing on the screen surface from the image projection device that projects the three-dimensional image is displayed at a location in a predetermined space before and after the surface of the screen. The screen itself must have the ability to form a viewing zone, that is, a viewing zone for a viewer.

In order to have this function, the flat and 3D image projection screen must have the same optical convergence power as a lens or a spherical mirror. Therefore, it is not only a spherical reflector and a lens that is used as a screen for simultaneous projection of flat and 3D images, but a lenticular plate in which semi-cylindrical lenses of the same characteristics are horizontally arranged, and slits of the same width are horizontally spaced at regular intervals. Parallax barrier plate arranged in parallel in the direction, Fresnel lens which is a flat lens, Integral Photography Plate with micro lenses of the same characteristics arranged in an area, and a holographic screen that acts as a lens or a spherical reflector there is.

However, in the case of a spherical reflector and a lens, since they themselves have a volume, if they are made large, the volume increases and the weight becomes heavy. On the other hand, other optical plates except for holographic screens have the form of a flat plate with these shortcomings reduced. Concave-Convex lenses or black streaks on the surface, so if you project an image to these optical plates and watch, the image quality will deteriorate due to the presence of irregularities or black streaks on the optical plate's surface. , causing discomfort to the viewer's eyes.

On the other hand, a holographic screen is a flat, high-resolution optical plate with no curvature on the surface, and the screen has excellent transparency and the brightness of the image is superior to that of other optical plates, so it is possible to display bright and clear three-dimensional images.

A holographic screen is a hologram made to project an image as one of the holographic optical elements (HOE). A natural-color image projection screen that can cover the wavelength range of all visible light with a spherical reflector or lens was introduced in 1996. was developed in the year This color holographic screen is a hologram using a long slit-shaped diffuser strip as an object, and by adjusting the length of the diffuser band and its relative position with the photosensitive plate during screen production, it is 40 inches with only a single wavelength laser beam. Although the distance between the diffusion band and the photosensitive plate used is only tens of cm, the beam diffused from the diffusion band illuminates more near the diffusion band than at the farthest part, and as the size increases, the uniformity of the screen decreases. In particular, there is a problem that the brightness decreases as the distance from the diffusion band increases, so screen recording of 40 inches or larger has never been attempted. The analog method for recording the holographic screen using a spherical reflector or lens is superior to the diffusion band method in terms of uniformity.

However, a spherical reflector or lens that is larger than the screen size must be used. For natural color display, separate red, green, and blue laser beams are used to create screens of each color and overlap each other, or combine the laser beams of three colors to record simultaneously. (Holographic Principles and Applications).

The digital holographic screen takes too much time to record, so it is difficult to manufacture a large screen, and it is difficult to increase the resolution, and it contains many aberrations. To solve this problem, the screen should be able to record in a short time without using a spherical reflector or lens.

Republic of Korea Patent Publication No. 10-2005-0049199 (2006.12.20)

The present invention was created to solve the above problems, and an object of the present invention is to produce a three-dimensional image projection screen of various sizes in a short time without using optical components such as a spherical reflector or a lens. An object of the present invention is to provide an apparatus and method for manufacturing a holographic screen for 3D image projection that can be manufactured simply and inexpensively.

According to a feature of the present invention for achieving the above object, the present invention is an apparatus for manufacturing a holographic screen for 3D image projection, comprising: a flat plate on which a photosensitive plate having a photosensitive emulsion applied on one surface is laminated; a transparent plate or a Fresnel lens laminated on the flat plate and printed with a diffraction pattern or a Fresnel pattern generated by calculation; and a light source for illuminating the expanded beam toward the transparent plate or the Fresnel lens.

In addition, in order to improve the uniformity of the surface of the holographic screen and expand the viewing area, a diffusion plate inserted and stacked between the transparent plate or the Fresnel lens and the photosensitive plate; may further include.

에 의해 계산하고(x와 y는 홀로그램의 수평 및 수직방향으로 점 (0,0)으로부터의 거리이고,

는 홀로그램 회절패턴 기록용 광의 파장이며, 그리고

는 이 회절패턴에 평행광 입사시 초점되는 광의 홀로그램으로부터의 거리임), 비 동축 회절패턴인 경우에는,

에 의해 계산된다(

와

은 각기 물체파와 기준파의 위치를 나타낸다. 그리고 z는 회절패턴에서 물체파와 기준파의 수직거리를 나타냄).At this time, the calculation of the diffraction pattern is, in the case of a chirped diffraction pattern,

Calculated by (x and y are the distances from the point (0,0) in the horizontal and vertical directions of the hologram,

is the wavelength of light for recording the hologram diffraction pattern, and

is the distance from the hologram of the focused light when parallel light is incident on this diffraction pattern), in the case of a non-coaxial diffraction pattern,

is calculated by (

Wow

represents the position of the object wave and the reference wave, respectively. And z represents the vertical distance between the object wave and the reference wave in the diffraction pattern).

In addition, the transparent plate may be a thin glass or transparent plastic plate or a Fresnel lens to which a printed film-like sheet is adhered.

On the other hand, according to a feature of the present invention for achieving the above object, the present invention is a method of manufacturing a holographic screen for 3D image projection, wherein the position of the object wave and the reference wave corresponding to the size and focal length of the desired screen is selected A diffraction pattern or Fresnel pattern corresponding to each wavelength or three primary colors is calculated through It is characterized in that the Fresnel pattern is engraved or printed on a transparent plate, and the pattern on the printed transparent plate is used as a screen, or it is transferred to a photosensitive plate and developed to use it as a screen.

According to the present invention, it can be used as a three-dimensional image projection screen having high transmittance and high diffraction efficiency, and in particular, since it is a holographic optical device that does not use a lens or a spherical reflector, it is simple to manufacture, so the pharmaceutical cost is low, and manufacturing Short time, mass production is possible, and there is an effect that is not limited by size.

1 is a diagram of the basic principle of recording a chirped or non-coaxial diffraction pattern, or Fresnel pattern;
2 is a diagram illustrating the calculation of a diffraction pattern or a Fresnel pattern capable of displaying one natural color by combining three diffraction patterns or Fresnel patterns calculated with light of red, green and blue wavelengths of the present invention;
3 is a diagram illustrating an apparatus for transferring a printed diffraction pattern, a Fresnel pattern, or a Fresnel lens pattern to the holographic photosensitive plate of the present invention.

Hereinafter, an apparatus and method for manufacturing a holographic screen for 3D image projection according to the present invention will be described in detail with reference to the accompanying drawings.

In a general flat image projection screen, randomly arranged fine particles that scatter the incident beam to the front space, like a diffuser, are distributed on the surface, but three-dimensional The image screen for image display visualizes the aperture of the projection lens of the image projector to form an image at a point in the space in front of the screen to create a viewing zone. should be able To this end, the screen must have a converging power that collects and converges the light incident on the surface from the image projector as in an optical component such as a spherical mirror or lens.

However, when a lens or a spherical reflector is directly used as a screen, the screen becomes large and heavy and bulky, making it unrealistic to use. To overcome these shortcomings, a flat lens combining digital and optomechanical methods, a Fresnel lens with the characteristics of a spherical reflector, a lenticular and Parallax barrier plate, and a micro lens Various projection screens, such as a Microlens Array, a Holographic grating Array, and a Polarization Array, have been developed and used.

However, these screens allow the multi-view image to be recognized three-dimensionally using parallaxes. Except for the Fresnel lens, a lens or a spherical reflector that can display the image of a real three-dimensional object in three dimensions and application characteristics are different.

Since a holographic screen is a plane capable of realizing holograms with the same characteristics as a lens or a spherical reflector, the surface shape is Convex and Concave, each having a constant Radius of Curvature similar to that of a lens or a spherical reflector. ) is more suitable for projecting planar and volumetric images compared to form. In addition, the holographic screen can make the viewing area larger and more uniform by using the object wave as a diffuse beam passing through a specific diffuser plate instead of a point light source during recording.

However, there are two methods of recording this holographic screen using a lens or a spherical reflector that is larger or at least the same size as the screen size to be produced, or recording using a diffuser plate as an object. As the size of the screen increases, it requires a larger diameter, making it unrealistic to manufacture. Therefore, it is not used in the production of screens with lens or spherical reflector characteristics, except when a color projection screen can be produced with a single laser beam such as a long and narrow diffuser plate.

Therefore, in order to manufacture a screen having a lens or a spherical reflector characteristic without using them, it is necessary to know their diffraction patterns when they are used in an image optical system. In the case of a lens or a spherical reflector, the point at which light generated from a point light source separated by a certain distance passes through the lens or is reflected by a spherical reflector and converged to form the image of the point light source is obtained by the lens formula.

The implementation of this image is the same as the principle in which the image of the original object is reproduced by a reconstruction wave in the hologram. In order to record the diffraction pattern of a hologram, a reference wave and an object wave, which are light beams generated from a single laser, which is a coherent light source, are required. The reference wave is a light beam directly generated from the laser, and the object wave refers to light reflected or transmitted by a light beam generated from the laser hitting an object. Therefore, the lens or the spherical reflector can be defined as the same diffraction pattern as the interference pattern formed by the interference between the reference wave and the object wave.

If an object is a point on a lens or a spherical reflector that is located on their optical axis, the image is also given as a point on the optical axis. In this case, a chirp-shaped diffraction pattern, that is, circular interference, which is a hologram diffraction pattern when the reference wave is a point light source and a hologram diffraction pattern when the same point light source and an object wave are spaced a certain distance in the normal direction of the photosensitive plate It is given as a diffraction pattern in which the period of the interference fringe is continuously increased or decreased.

In general, when the distance between the object wave and the reference wave from the hologram is much larger than the size in each direction of the hologram, the approximate expression of the chirped diffraction pattern is given by the cosine function as in Equation 1 below.

는 홀로그램 회절패턴 기록용 광의 파장, 그리고

는 이 회절패턴에 평행광 입사시 초점되는 광의 홀로그램으로부터의 거리로 초점거리(Focal Length)라 명명된다.

는 홀로그램 회절패턴 기록시 물체파와 기준파의 거리를 분모로 한 분수를 서로 빼준 값의 역을 취하여 얻어진 값이다. In [Equation 1], when a point in the hologram is (0,0), x and y represent the distance from the point (0,0) in the horizontal and vertical directions of the hologram,

is the wavelength of light for recording the hologram diffraction pattern, and

is the distance from the hologram of the focused light when parallel light is incident on this diffraction pattern, and is called focal length.

is a value obtained by taking the inverse of the value obtained by subtracting the fraction of the distance between the object wave and the reference wave as the denominator when recording the hologram diffraction pattern.

If the object wave and the reference wave are not on the axis (z-axis) along the normal vector direction of the hologram at the point (0,0), that is, even in the case of the off axis, the diffraction pattern is cosine. Given as a function, the phase within the cosine is slightly different. In this case, the diffraction pattern is an interference pattern with a very large radius of curvature and is expressed by the following equation.

와

은 각기 물체파와 기준파의 위치를 나타낸다. 그리고 z는 회절패턴에서 물체파와 기준파의 수직거리를 나타낸다. 만약 [수학식 1]과 [수학식 2]에서 일정 곡률반경을 가진 스크린의 회절패턴 계산을 위해서는 곡률반경에 의해 평면형 스크린으로부터 벌어진 수직거리를 중심축 상의 z값에서 빼준 z값을 사용하면 된다. In [Equation 2]

Wow

represents the position of the object wave and the reference wave, respectively. And z represents the vertical distance between the object wave and the reference wave in the diffraction pattern. If in [Equation 1] and [Equation 2], in order to calculate the diffraction pattern of a screen having a certain radius of curvature, the z value obtained by subtracting the vertical distance from the flat screen by the radius of curvature from the z value on the central axis is used.

In the present invention, 1) by selecting the location of the object wave and the reference wave corresponding to the size and focal length of the desired screen, 2) a chirped or non-ipsilateral diffraction pattern, or a Fresnel pattern, using each wavelength or three primary colors 3) These diffraction patterns for each wavelength or a combination of Fresnel patterns, or Fresnel patterns, or individual diffraction patterns or Fresnel patterns are 4) engraved or printed on transparent glass or plastics; 5) The pattern recorded on this engraved or printed transparent glass or plastic is transferred to a photosensitive plate for hologram recording and developed to make a screen.

만큼 떨어진 광축(2) 상의 한 점에 놓인 기준파용 광원(4)에서 발생하는 광선(5)와 감광판(1)로부터

만큼 떨어져 광축(2) 상의 다른 한 점에 위치하는 물체(7)에 의해 반사 또는 투과되는 물체파의 광선(8) 의해 감광판(2)에 처프형 회절패턴(9) 또는 기준파를 평행광으로 하여 물체파와 간섭에 의한 프레넬 패턴(9)이 기록된다. 1 shows the calculation and recording of the diffraction pattern values calculated for each wavelength by adding the diffraction pattern values of points having the same (x,y) value to calculate and record the diffraction pattern simultaneously representing the colors for each wavelength, chirped or non-chirped. It is a basic principle diagram for recording a coaxial diffraction pattern, or a Fresnel pattern. The distance from the photosensitive plate (1) to the optical axis (2) that is derived from one laser beam and coincides with the normal vector of the photosensitive plate (1) for diffraction pattern recording

From the light beam 5 and the photosensitive plate 1 from the light source 4 for the reference wave placed at a point on the optical axis 2 separated by

The chirped diffraction pattern 9 or the reference wave is converted into parallel light on the photosensitive plate 2 by the ray 8 of the object wave reflected or transmitted by the object 7 located at another point on the optical axis 2 as far away as possible. Thus, the Fresnel pattern 9 due to interference with the object wave is recorded.

In the case of the non-coaxial diffraction pattern, instead of the beam 8 of the object wave located on the optical axis 2, the object wave beam 11 provided by the object 10 located at a point other than the optical axis 2 is used. record If the object is not approximated by a single point, the diffusion plate is given as a set of object waves generated by each of the points 12, in which several points are randomly arranged at minute distance intervals.

FIG. 2 is a diagram illustrating calculation of a diffraction pattern or Fresnel pattern capable of displaying one natural color by combining three diffraction patterns or Fresnel patterns calculated with light of red, green, and blue wavelengths according to the present invention. Using the wavelength of a laser corresponding to each wavelength of blue, green and red, chirped or non-coaxial blue, green and red diffraction patterns or Fresnel patterns based on [Equation 1] or [Equation 2] ( 13, 14, and 15) are calculated, and if necessary, the calculated values of these three-color diffraction patterns or Fresnel patterns are added to form a natural color diffraction pattern or Fresnel pattern 16.

And each of these is engraved or printed on a transparent glass plate, transparent film, or transparent plastic plate, and in the case of a transparent film, air bubbles are minimized and adhered to the glass plate or plastic plate to be used as a monochromatic screen, or a natural color image Used as a projection screen.

3 is a diagram illustrating an apparatus for transferring a printed diffraction pattern, a Fresnel pattern, or a Fresnel lens pattern to the holographic photosensitive plate of the present invention. In general, when the diffraction pattern calculated in FIG. 2 is directly printed and used, since the pattern is printed in black and white, the brightness of the screen is reduced by absorption of incident light by this pattern, and as a result, the diffraction efficiency is also reduced. In order to solve this problem, it is necessary to transfer the black and white diffraction pattern to the holographic photosensitive plate as in the development of a photograph, and to replace the gray level of black and white with a change in the refractive index.

A film type sheet 17 on which a diffraction pattern or Fresnel pattern of each color is printed is directly or bonded to a thin glass or transparent plastic plate 18 without air bubbles, and the diffusion plate 20 ), and in the case of the Fresnel lens 19, it is placed directly on the diffuser plate 20. The distance between the sheet 17, transparent glass or plastic plates 18 and 19 and the diffusion plate 20 is when the expanded beam 24 from the laser 23 or lamp light source 23 is parallel light. Since the negative (positive) angle or pattern is transferred as it is, it is preferable that the printed surface face the diffuser plate 20 and are laminated. Since it is necessary to keep some distance from it, it is necessary to laminate it with the surface of the substrate on which the negative (positive) angles or patterns are not printed.

The diffuser plate 20 is placed on the photosensitive plate or photosensitive sheet 22 bonded to the flat plate 21 to increase the surface uniformity of the screen to be manufactured and to enlarge the viewing area. The photosensitive plate or photosensitive sheet 22 makes the photosensitive emulsion-coated layer face the diffuser plate 20 so that the pattern of the diffuser plate 20 is well transferred to the photosensitive plate. However, since the degree of diffusion of the diffusion plate 20 may reduce the convergence force due to the diffraction pattern or the Fresnel pattern, in order to reduce the diffusion degree, a substrate layer coated with a photosensitive emulsion or a substrate layer of the diffusion plate 20 . (Substrate) can be faced or removed. A thin glass or transparent plastic plate 18 or a Fresnel lens to which a printed film type sheet 17 is attached is a laser or lamp light source 23 for each diffraction pattern on it. Illuminated by an enlarged beam 24 from

By this illumination, the pattern on the printed Film Type sheet 17 or the Fresnel pattern engraved on the Fresnel lens is replaced by a change in refractive index on the photosensitive plate or the photosensitive emulsion layer of the photosensitive sheet 22 become imitated This simulated pattern has excellent transmittance and diffraction efficiency as the black and white and gray levels of the printed pattern are replaced by a change in refractive index.

Also, in order to replace the gray level of the printed diffraction pattern or the Fresnel pattern or the engraved pattern of the Fresnel lens with the change in the refractive index of the photosensitive emulsion layer, a laser beam of a wavelength used for calculating the diffraction pattern or Fresnel pattern can be used as illumination. .

In addition, the natural color diffraction pattern or the Fresnel pattern may use a laser of a visible wavelength as illumination.

The right of the present invention is not limited to the above-described embodiments, but is defined by the claims, and a person of ordinary skill in the art can make various modifications and adaptations within the scope of the claims. it is self-evident

1: Photosensitive plate for diffraction pattern recording
2: Optical Axis
4 ; Light source for reference wave on optical axis
5 ; Rays from the light source for the reference wave
7 ; An object located at a point different from the light source of the reference wave on the optical axis
8 ; Object wave rays reflected or transmitted by an object
9 ; Diffraction pattern or Fresnel pattern due to interference of object wave and reference wave
10 ; An object located at a point off the optical axis
11 ; object wave light source
12 ; Randomly arranged points with small distance intervals
13 ; Chirped or non-coaxial blue diffraction pattern/Fresnel pattern
14 ; Chirped or non-coaxial green diffraction pattern/Fresnel pattern
15 ; Chirped or non-coaxial red diffraction pattern/Fresnel pattern
16 ; Natural color diffraction pattern/Fresnel pattern
17 ; Diffraction pattern / Fresnel lens print sheet / Fresnel lens
18 ; thin glass or clear plastic plate
19 ; Clear glass or plastic plate with negative (embossed) embossed diffraction pattern/Fresnel pattern of each color
20 ; diffuser plate
21 ; reputation
22 ; Photosensitive plate or photosensitive sheet
23 ; light source
24 ; enlarged light beam

Claims (17)

a flat plate on which a photosensitive plate having a photosensitive emulsion applied on one surface is laminated;
a transparent plate or Fresnel lens laminated on the flat plate, on which a diffraction pattern or a Fresnel pattern generated by calculation is engraved or printed; and
A light source for illuminating the beam expanded toward the transparent plate or the Fresnel lens;
The calculation of the diffraction pattern is,
In the case of a chirped diffraction pattern,

Calculated by (x and y are the distances from the point (0,0) in the horizontal and vertical directions of the hologram,

is the wavelength of light for recording the hologram diffraction pattern, and

is the distance from the hologram of the focused light when parallel light is incident on this diffraction pattern),
In the case of a non-coaxial diffraction pattern,

which is calculated by (

Wow

represents the position of the object wave and the reference wave, respectively. And z represents the vertical distance between the object wave and the reference wave in the diffraction pattern)
A device for manufacturing a holographic screen for 3D image projection, characterized in that
According to claim 1,
The apparatus for manufacturing a holographic screen for 3D image projection further comprising; a diffusion plate inserted and stacked between the transparent plate or the Fresnel lens and the photosensitive plate to improve the uniformity of the surface of the holographic screen and expand the viewing area.
delete According to claim 1,
The transparent plate is an apparatus for manufacturing a three-dimensional image projection holographic screen, characterized in that a thin glass or transparent plastic plate or a Fresnel lens to which a printed film sheet is adhered.
3. The method of claim 2,
The diffusion plate is an apparatus for manufacturing a three-dimensional image projection holographic screen, characterized in that used to improve the brightness uniformity of the screen and increase the viewing area.
3. The method of claim 2,
An apparatus for manufacturing a holographic screen for 3D image projection, characterized in that the negative (positive) or printed diffraction pattern or Fresnel pattern faces the diffusion plate.
3. The method of claim 2,
An apparatus for manufacturing a holographic screen for 3D image projection, characterized in that the negative (positive) or printed diffraction pattern or Fresnel pattern does not face the diffusion plate.
8. The method of claim 7,
An apparatus for manufacturing a holographic screen for 3D image projection, characterized in that the intaglio pattern of the Fresnel lens faces the diffusion plate.
3. The method of claim 2,
An apparatus for manufacturing a holographic screen for 3D image projection, characterized in that the photosensitive emulsion layer of the photosensitive plate faces the diffusion plate.
According to claim 1,
A 3D image projection hole characterized in that it illuminates using a laser beam of a wavelength used for calculating the diffraction pattern or Fresnel pattern to replace the gray level of the printed diffraction pattern or the Fresnel pattern with the change in the refractive index of the photosensitive emulsion layer. A device for producing graphic screens.
According to claim 1,
An apparatus for manufacturing a 3D image projection holographic screen, characterized in that it is illuminated with lamp light to replace the gray level of the printed diffraction pattern or the Fresnel lens engraved pattern with a change in the refractive index of the photosensitive emulsion layer.
12. The method of claim 1 or 11,
A device for manufacturing a holographic screen for 3D image projection, characterized in that the natural color diffraction pattern or Fresnel pattern is illuminated with lamp light.
According to claim 1,
A device for manufacturing a holographic screen for 3D image projection, characterized in that the natural color diffraction pattern or Fresnel pattern is illuminated using a laser having a wavelength in the visible region.
9. The method of claim 1 or 8,
A device for manufacturing a holographic screen for 3D image projection, characterized in that the Fresnel lens and the diffusion plate are brought into close contact.
9. The method of claim 1 or 8,
An apparatus for manufacturing a holographic screen for 3D image projection, characterized in that the Fresnel lens and the diffusion plate are spaced apart by a certain distance.
8. The method of claim 1 or 7,
A device for manufacturing a holographic screen for 3D image projection, characterized in that the intaglio pattern of the Fresnel lens faces the light source.
A diffraction pattern or Fresnel pattern corresponding to each wavelength or three primary colors is calculated by selecting the location of an object wave and a reference wave corresponding to the size and focal length of the desired screen, and the diffraction pattern or Fresnel pattern for each wavelength or color, or The diffraction pattern or Fresnel pattern combined with the rotation pattern or Fresnel pattern for each wavelength or color is printed on a transparent plate, and the printed pattern on the transparent plate is used as a screen, or transferred to a photosensitive plate and developed to be used as a screen, ,
The calculation of the diffraction pattern is,
In the case of a chirped diffraction pattern,

Calculated by (x and y are the distances from the point (0,0) in the horizontal and vertical directions of the hologram,

is the wavelength of light for recording the hologram diffraction pattern, and

is the distance from the hologram of the focused light when parallel light is incident on this diffraction pattern),
In the case of a non-coaxial diffraction pattern,

which is calculated by (

Wow

represents the position of the object wave and the reference wave, respectively. And z represents the vertical distance between the object wave and the reference wave in the diffraction pattern)
A method of manufacturing a holographic screen for 3D image projection, characterized in that

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