Dual holographic printing apparatus

Abstract

To provide a dual holographic printing device and method for recording a multiple perspectives image printed by a stereogram system and a wave front reproduced from a CGH.SOLUTION: A plurality of lasers having different wavelengths, a plurality of dichroic lenses and mirrors combining beams output from the lasers into one beam and outputting the beam as a white beam, a plurality of beam splitters separating the white beam output through the plurality of dichroic lenses and mirrors into a beam sent to each of a stereogram printing device and a wavefront printing device and another beam and further separating the another beam and sending the another beam as a reference beam to each of the stereogram printing device and the wavefront printing device, and a hologram is printed with the beam sent through the beam splitters.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a holographic printing technology, and more particularly to a dual holographic printing device and method that prints multi-viewpoint images in a stereogram format using hogels in a single device, or records a wavefront reconstructed from a computer-generated hologram (CGH). [Background technology]

[0002] Holograms are an imaging technology that allows us to perceive virtual reality as reality, and have been the subject of much research and development. Holograms are created by splitting the beam emitted from a laser light source into two beams using a beam splitter, shining one beam onto a reflecting mirror and the other onto a subject. The light scattered by the subject (object beam) and the light reflected by the reflecting mirror (reference beam) overlap, creating interference fringes, which are then recorded in the holographic medium.

[0003] Digital holographic printing technology can be broadly divided into holographic stereogram printing technology and holographic wavefront printing technology. Holographic stereogram printing creates multi-viewpoint images with vertical and horizontal parallax using an object beam, then forms interference fringes with a reference beam and records them on a photosensitive medium. Using this recording method, each hologram is printed as a single unit hologram that acts as a lens. In other words, this method displays multi-viewpoint images using holographic recording technology by capturing multiple perspective projection images of a 3D object and recording them on a holographic recording medium. Holographic wavefront printers generate a holographic interference pattern for a 3D object and then record the wavefront diffracted by the interference pattern on a holographic recording medium, displaying the wavefront of the 3D object like an analog film hologram. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Korean Patent Publication No. 10-2022-0075116 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a dual holographic printing device and method that records, in a single device, a multi-view image printed in a stereogram format using a holographic element (Hogel) through a holographic stereogram printer and a wavefront reproduced from a Computer Generated Hologram (CGH) recorded through a holographic wavefront printer.

[0006] The problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0007] To achieve the above object, a first aspect of the present invention provides a dual holographic printing device, comprising: a plurality of lasers exhibiting different wavelengths; a plurality of dichroic lenses and mirrors that combine beams output from the plurality of lasers into one beam and output the combined beam as a white beam; a plurality of beam splitters that split the white beam output through the plurality of dichroic lenses and mirrors into a beam and another beam that are sent to a stereogram printing device and a wavefront printing device, respectively, and further split the other beams to send them as reference beams to the stereogram printing device and the wavefront printing device, respectively; and a computer that controls the stereogram printing device and the wavefront printing device so that a hologram is printed using the beam sent through the beam splitters.

[0008] Preferably, the plurality of lasers include three lasers, first to third, that output beams of different wavelengths representing R, G, and B, and the first to third lasers can output beams of wavelengths of 660 nm, 532 nm, and 473 nm, respectively.

[0009] Preferably, the system may further include a plurality of acousto-optic modulators arranged in front of the plurality of lasers and connected to and controlled by the computer.

[0010] Preferably, the plurality of dichroic lenses are disposed in front of the first and second lasers, respectively, and pass the beams output from the first and second lasers and refract them in a specific direction; the mirror is disposed in front of the third laser and reflects the beam output from the third laser in a specific direction; and the beams that have passed through the plurality of dichroic lenses and the beam reflected by the mirror can be combined into one light beam.

[0011] Preferably, the plurality of beam splitters may include a first beam splitter that splits the beam reflected by the mirror and sends it to the stereogram printing device, a second beam splitter that splits the beam that has passed through the first beam splitter and sends it to the wavefront printing device, and a third beam splitter that splits the beam that has passed through the second beam splitter and sends a reference beam to the stereogram printing device and the wavefront printing device, respectively.

[0012] Preferably, the computer can control a first automatic ND filter and a first shutter of the stereogram printing device, and a second automatic ND filter and a second shutter of the wavefront printing device, so that holographic stereogram printing or holographic wavefront printing is performed.

[0013] Preferably, in order to perform holographic stereogram printing in the first spatial light modulator, the computer activates a first automatic ND filter of the first and second automatic ND filters that are currently inactivated to a maximum value, and activates a first shutter of the first and second shutters that are currently inactivated while displaying an image corresponding to specific coordinates of a hogel, which is an elementary hologram, so that the holographic medium is exposed for a specific exposure time.

[0014] Preferably, after the holographic medium has been exposed for the specified exposure time, the computer can deactivate the first automatic ND filter and the first shutter and move the XY stage to record an elementary hologram at the next coordinate after the specified coordinate.

[0015] Preferably, in order to perform holographic wavefront printing in the second spatial light modulator, the computer activates the second automatic ND filter of the first and second automatic ND filters that are currently inactivated to a maximum value, and activates the second shutter of the first and second shutters that are currently inactivated while displaying an image corresponding to specific coordinates of the elementary hologram, thereby exposing the holographic medium for a specific exposure time.

[0016] Preferably, after the holographic medium has been exposed for the specified exposure time, the computer can deactivate the second spatial light modulator and the second shutter and move the XY stage to record an elementary hologram at the next coordinate after the specified coordinate.

[0017] Preferably, in order to perform holographic stereogram printing and holographic wavefront printing in the first and second spatial light modulators, the computer activates a first automatic ND filter of the first and second inactivated automatic ND filters to a maximum value, and activates a first shutter of the first and second inactivated shutters while displaying an image corresponding to specific coordinates of an elementary hologram, thereby exposing the holographic medium for a specific exposure time.

[0018] Preferably, after the holographic medium is exposed for the specific exposure time, the computer deactivates the first spatial light modulator and the first shutter, activates the second automatic ND filter of the first and second automatic ND filters that are previously deactivated to a maximum value, and activates the second shutter of the first and second shutters that are previously deactivated while displaying an image corresponding to specific coordinates of the elementary hologram, thereby exposing the holographic medium for the specific exposure time.

[0019] Preferably, after the holographic medium has been exposed for the specified exposure time, the computer can deactivate the second spatial light modulator and the second shutter and move the XY stage to record an elementary hologram at the next coordinate after the specified coordinate. [Effects of the Invention]

[0020] As described above, according to the present invention, two types of holograms can be printed using one device, and the conventional hologram printing device, which requires a large volume, can be realized in one device, thereby reducing manufacturing costs and thereby expanding the applicability in various industrial fields.

[0021] In addition, by using lasers of various wavelengths and processing the beams using one optical system, it is possible to selectively output high-resolution and high-quality holograms required for stereograms and wavefront printers, thereby enabling the incorporation of images with detailed and complex designs that meet user demands and enabling the development of more innovative and original products.

[0022] In addition, because each process is precisely controlled through a computerized system, the automated functions improve work efficiency and reduce the possibility of errors in the manufacturing process, thereby improving productivity, shortening development time, and accelerating the market entry of new products and technologies.

[0023] In addition, its multi-functionality and high-resolution output capability make it suitable for a variety of applications. For example, it can be used to generate high-resolution medical images in the medical field, and to create safe and reliable holograms in the security field.

[0024] It can also be used in a wide range of research and development fields, such as experimenting and evaluating new materials and processes, and exploring new holographic application fields, which will lead to further understanding and innovative discoveries. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a block diagram illustrating a dual holographic printing device according to a preferred embodiment of the present invention. [Figure 2] FIG. 1 illustrates a computer of a dual holographic printing apparatus according to one embodiment. [Figure 3] FIG. 1 is a flowchart illustrating a dual holographic printing method according to an embodiment. [Figure 4] FIG. 10 is a flowchart illustrating a dual holographic printing method according to another embodiment. [Figure 5] FIG. 10 is a flowchart illustrating a dual holographic printing method according to another embodiment. [Figure 6] 1 is an exemplary diagram illustrating an automatic ND filter according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0026] The advantages and features of the present invention, as well as methods for achieving them, will become clearer with reference to the following detailed description of the embodiments accompanied by the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be realized in various different forms. However, the present embodiments are provided so that this disclosure will be complete and will fully convey the scope of the invention to those skilled in the art to which the present invention pertains. The present invention is defined only by the scope of the claims. The same reference symbols refer to the same elements throughout the specification. The term "and / or" includes each and every combination of one or more of the referenced items.

[0027] Even if terms such as "first," "second," and "second" are used to describe various elements, components, and / or sections, it is understood that these elements, components, and / or sections are not limited by these terms. These terms are used merely to distinguish one element, component, or section from another. Therefore, it is understood that a first element, first component, or first section referred to below may be a second element, second component, or second section within the technical spirit of the present invention.

[0028] Furthermore, the identification numbers (e.g., a, b, c, etc.) used in each step are for convenience of explanation and do not describe the order of each step, and each step may be performed in a different order than specified unless a specific order is clearly stated in the context. That is, each step may be performed in the same order as specified, substantially simultaneously, or in the opposite order.

[0029] The terms used in this specification are for the purpose of describing embodiments and are not intended to limit the present invention. In this specification, the singular form includes the plural form unless expressly stated otherwise. When used in this specification, the words "comprises" and / or "comprising" mean that a referenced component, step, operation, and / or element does not exclude the presence or addition of one or more other components, steps, operations, and / or elements.

[0030] Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in a manner commonly understood by those skilled in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries should not be interpreted ideally or excessively unless expressly defined otherwise.

[0031] Furthermore, when describing embodiments of the present invention, if it is determined that a detailed description of a known function or configuration may obscure the gist of the present invention, the detailed description will be omitted. Furthermore, the terms used below are defined in consideration of the functions in the embodiments of the present invention, and may vary depending on the intentions or practices of users or operators. Therefore, the definitions should be interpreted based on the entire content of this specification.

[0032] FIG. 1 is a block diagram illustrating a dual holographic printing device according to a preferred embodiment of the present invention.

[0033] The dual holographic printing apparatus performs both holographic stereogram printing and holographic wavefront printing in a single device, allowing users to selectively perform either holographic stereogram printing or holographic wavefront printing. That is, unlike conventional techniques that separately construct stereogram printing and wavefront printing devices, the dual holographic printing apparatus of the present invention utilizes the same optical system to dualize the stereogram printing device and wavefront printing device, and uses a single XY stage. Referring to FIG. 1, the dual holographic printing apparatus includes a plurality of lasers 111-113, a plurality of waveplates 120 and 130, a plurality of dichroic lenses 141 and 142, a plurality of mirrors 151-158, and a plurality of beam splitters 161-165, thereby comprising a stereogram printing device and a wavefront printing device.

[0034] Preferably, the stereogram printing device includes a first automatic ND filter 171, a spatial filter 181, a collimation lens 191, a first spatial light modulator 211, a beam splitter 164, a mirror 157, a first optical head 221, and a holographic medium 231, and the wavefront printing device includes a second automatic ND filter 172, a spatial filter 182, a collimation lens 192, a second spatial light modulator 212, a beam splitter 165, a mirror 158, a second optical head 222, and a holographic medium 232. Here, the stereogram printing device and the wavefront printing device differ in the configurations of the spatial light modulators and the optical heads, but the remaining configurations are the same. The stereogram printing device 211 can display a multi-view image such as a lenticular image using a general LCD display, and the wavefront printing device 212 can display a computer-generated hologram (CGH) pattern using a spatial light modulator (SLM). The stereogram printing device 221 can be designed so that its optical system focuses on a film, while the wavefront printing device 222 can be designed so that its optical system does not focus but instead emits parallel light with a small hogel size.

[0035] The plurality of lasers 111 to 113 include three coherence lasers that output beams of different wavelengths representing R, G, and B. For example, the first laser 111 may be a coherence laser with a wavelength of 660 nm, the second laser 112 may be a coherence laser with a wavelength of 532 nm, and the third laser 113 may be a coherence laser with a wavelength of 457 nm.

[0036] The beams output from the first to third lasers 111 to 113 pass through an acousto-optic modulator (AOM) located in front of them, and then through multiple wave plates 120 and 130. Here, the AOM has a shutter function that acts as an on / off switch by modulating the direction of light, and the multiple wave plates 120 and 130 can be finely adjusted to set the optimal light amount by changing the wavelength to increase or decrease the amount of light. In other words, when a hologram is recorded, high efficiency is achieved when the same polarized light is superimposed, but distortions in the polarization may occur due to the combination of various different optical components (e.g., lenses, mirrors, etc.), and such distortions can be finely adjusted using the multiple wave plates. Preferably, the plurality of wave plates 120 and 130 may include a wave plate 120 corresponding to 1 / 2λ and a wave plate 130 corresponding to 1 / 4λ, and the wave plate 120 corresponding to 1 / 2λ and the wave plate 130 corresponding to 1 / 4λ may be sequentially arranged in front of the first to third lasers 111 to 113, respectively.

[0037] The beams output from the first to third lasers 111 to 113 and passing through the plurality of wave plates 120 and 130 are combined into one beam via the plurality of dichroic lenses 141 and 142 arranged in front of the plurality of wave plates 120 and 130 and the mirror 151, and are then output as a white beam. Preferably, the beams output from the first and second lasers 111 and 112 pass through the plurality of wave plates 120 and 130 and are then refracted in a specific direction via the dichroic lenses 141 and 142, and the beam output from the third laser 113 passes through the plurality of wave plates 120 and 130 and is then reflected in a specific direction via the mirror 151. That is, the beams that have passed through the dichroic lenses 141 and 142 and the light reflected by the mirror 151 are combined into one beam.

[0038] The white beam formed by combining the light beams into one light beam is redirected by mirror 152 and enters first beam splitter 161. Preferably, first beam splitter 161 splits the beam and sends it to the stereo printing device, and the remaining split beam is directed to second beam splitter 162. Second beam splitter 162 splits the beam and sends it to the wavefront printing device, and the remaining split beam is directed to third beam splitter 163 via mirror 153. Third beam splitter 163 splits the beam into a reference beam that enters the stereogram printing device and a reference beam that enters the wavefront printing device. The reference beam that enters the stereogram printing device is reflected by mirror 154, passes through first shutter 241, and is further reflected by mirror 155 to enter the stereogram printing device. The reference beam entering the wavefront printing device is split off via the third beam splitter 163, passes through the second shutter 242, and is then reflected by the mirror 156 into the wavefront printing device.

[0039] Preferably, the dual holographic printing apparatus may include a computer 250, which may control the stereogram printing apparatus and the wavefront printing apparatus so that holograms are printed. That is, referring to FIG. 2, the computer 250 is connected to first and second automatic ND filters 171 and 172, first and second spatial light modulators (SLMs) 211 and 212, and first and second shutters 241 and 242, and may control the first automatic ND filter 171 and the first shutter 241 to perform holographic stereogram printing in the first spatial light modulator 211, and may control the second automatic ND filter 172 and the second shutter 242 to perform holographic wavefront printing in the second spatial light modulator 212. The dual holographic printing method performed by the computer 250 will be described in more detail below with reference to FIGS. 3 to 5.

[0040] Preferably, the computer 250 can be installed with an application or program for performing the dual holographic printing method and can have a user interface to control data input and output. Here, the computer 250 refers to any type of hardware device including at least one processor, and may also be understood to encompass software configurations operating on the corresponding hardware device, depending on the embodiment. For example, the computer 250 may be understood to include, but is not limited to, a smartphone, tablet PC, desktop PC, laptop computer, and user clients and applications running on each device.

[0041] In one embodiment, detailed operations of the dual holographic printing method performed by computer 250 include holographic stereogram printing performed by first optical head 221 and holographic wavefront printing performed by second optical head 222. Here, an optical head is a collection of multiple lasers used to reduce incoming light to a desired size or focus it at a desired position. Since using only one or two lenses results in significant aberrations, first optical head 221 used in the stereogram printing device may be configured to effectively focus light from an incoming multi-viewpoint image onto a single location on the film, and second optical head 222 used in the wavefront printing device may be configured to align an incoming CGH image parallel to the hogel size and impinge on a single location on the film. Preferably, computer 250 is capable of holographic printing in the following three cases: 1) Only holographic stereogram printing can be performed, which will be described with reference to FIG. 3. 2) Only holographic wavefront printing can be performed, which will be described with reference to Figure 4. 3) Both holographic stereogram printing and holographic wavefront printing can be performed, which will be described with reference to Figure 5.

[0042] Preferably, before dual holographic printing is performed, the first to third lasers 111 to 113, the first and second automatic ND filters 171 and 172, the first and second spatial light modulators 211 and 212, and the first and second shutters 241 and 242 of the dual holographic printing device are all deactivated as an initial setting, and the hogel coordinates are defined as (Hx, Hy) and the unit hologram coordinates are defined as (Ex, Ey).

[0043] FIG. 3 is a flow chart illustrating a dual holographic printing method according to one embodiment.

[0044] First, in preparation for recording a hologram, the first to third lasers 111 to 113 of the dual holographic printing device are turned on, the first and second automatic ND filters 171 and 172 are deactivated to completely block light, and the first and second shutters 241 and 242 are also deactivated to prevent light from being irradiated onto the holographic media 231 and 232.

[0045] Referring to FIG. 3, to perform stereogram printing using first spatial light modulator 211 that outputs a holographic stereogram image, computer 250 activates first automatic ND filter 171 to its maximum value (step S310). Here, first automatic ND filter 171 reduces the amount of light entering collimation lens 191, and the amount of light entering first spatial light modulator 211 may be automatically controlled from 0% to 100% under the control of computer 250. Also, referring to FIG. 6, the area indicated by a red box is an area that can completely block light, and computer 250 drives motor 610 of first automatic ND filter 171 to control first automatic ND filter 171 to be activated to its maximum value. The same applies to second automatic ND filter 172. If the ND filter cannot reduce the amount of light when performing wavefront printing, the light shining in the stereogram printing device will interfere with the wavefront printing. Conversely, if the ND filter cannot reduce the amount of light when performing stereogram printing, the light shining in the wavefront printing device will interfere with the stereogram printing.

[0046] The computer 250 activates the first shutter 241 (step S320) while displaying an image corresponding to specific coordinates (Hx0, Hy0) of the hogel, which is an elementary hologram, and exposes the holographic medium 231 for a specific exposure time (step S330). Here, the first shutter 241 controls the reference beam to record the hologram and perform holographic stereogram printing.

[0047] After the holographic medium 231 has been exposed for a specific exposure time, the computer 250 deactivates the first automatic ND filter 171 and the first shutter 241 (step S340).

[0048] The computer 250 checks whether the coordinates of the displayed image are the last coordinates (step S350). If the coordinates of the displayed image are the last coordinates, the holographic stereogram printing is considered complete and the operation ends. If the coordinates of the displayed image are not the last coordinates, the computer 250 moves the XY stage to the next coordinates to record the hogel at the next coordinates (step S360) and repeats steps S320 to S340. Through this, holograms are recorded from (Hx0, Hy0) to (Hxn, Hyn).

[0049] FIG. 4 is a flow chart illustrating a dual holographic printing method according to another embodiment.

[0050] First, in preparation for recording a hologram, the first to third lasers 111 to 113 of the dual holographic printing device are turned on, the first and second automatic ND filters 171 and 172 are deactivated to completely block light, and the first and second shutters 241 and 242 are also deactivated to prevent light from being irradiated onto the holographic media 231 and 232.

[0051] 4, to perform wavefront printing with the second spatial light modulator 212 that outputs a holographic wavefront stereogram image, the computer 250 activates the second automatic ND filter 172 to its maximum value (step S410). The second automatic ND filter 172 reduces the amount of light entering the collimation lens 192, and the amount of light entering the second spatial light modulator 212 may be automatically controlled from 0% to 100% under the control of the computer 250.

[0052] The computer 250 activates the second shutter 242 (step S420) while displaying an image corresponding to specific coordinates (Ex0, Ey0) of the elemental hologram (EH), which is a unit hologram, and exposes the holographic medium 232 for a specific exposure time (step S430). Here, the second shutter 242 controls the reference beam to record a hologram and perform holographic wavefront printing.

[0053] After the holographic medium 232 has been exposed for a specific exposure time, the computer 250 deactivates the second automatic ND filter 172 and the second shutter 242 (step S440).

[0054] Computer 250 checks whether the coordinates of the displayed image are the last coordinates (step S450). If the coordinates of the displayed image are the last coordinates, the holographic wavefront printing is considered complete and the operation ends. If the coordinates of the displayed image are not the last coordinates, computer 250 moves the XY stage to the next coordinates to record a unit hologram at the next coordinates (step S460), and repeats steps S420 to S440. Through this, holograms from (Ex0, Ey0) to (Exn, Eyn) are recorded.

[0055] FIG. 5 is a flow chart illustrating a dual holographic printing method according to another embodiment.

[0056] First, in preparation for recording a hologram, the first to third lasers 111 to 113 of the dual holographic printing device are turned on, the first and second automatic ND filters 171 and 172 are deactivated to completely block light, and the first and second shutters 241 and 242 are also deactivated to prevent light from being irradiated onto the holographic media 231 and 232. When stereogram printing and wavefront printing are performed simultaneously, the stage moves to the next coordinate after the stereogram hologram is recorded and then the wavefront hologram is recorded.

[0057] Referring to FIG. 5, in order to perform holographic stereogram printing with the first spatial light modulator 121, the computer 250 activates the first automatic ND filter 171 to its maximum value (step S501).

[0058] The computer 250 activates the first shutter 241 (step S502) while displaying an image corresponding to specific coordinates (Hx0, Hy0) of the hogel, which is an elementary hologram, so that the holographic medium 231 is exposed for a specific exposure time (step S503).

[0059] After the holographic medium 231 has been exposed for a specific exposure time, the computer 250 deactivates the first automatic ND filter 171 and the first shutter 241 (step S504).

[0060] To perform holographic wavefront printing with the second spatial light modulator 122, the computer 250 activates the second automatic ND filter 172 to its maximum value (step S505).

[0061] The computer 250 activates the second shutter 242 (step S506) while displaying an image corresponding to specific coordinates (Ex0, Ey0) of the unit hologram EH, thereby exposing the holographic medium 232 for a specific exposure time (step S507).

[0062] After the holographic medium 232 has been exposed for a specific exposure time, the computer 250 deactivates the second automatic ND filter 172 and the second shutter 242 (step S508).

[0063] Computer 250 checks whether the coordinates of the displayed image are the last coordinates (step S509). If the coordinates of the displayed image are the last coordinates, the holographic stereogram printing and holographic wavefront printing are completed, and the operation ends. If the coordinates of the displayed image are not the last coordinates, the XY stage is moved to the next coordinates (step S510), and steps S502 to S508 are repeated. Through this, holograms are recorded from (Hx0, Hy0) to (Hxn, Hyn) and from (Ex0, Ey0) to (Exn, Eyn).

[0064] The steps of a method or algorithm described in connection with embodiments of the present invention may be embodied directly in hardware, in a software module executed by hardware, or in a combination thereof. The software module may reside in Random Access Memory (RAM), Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), Flash Memory, a hard disk, a removable disk, a CD-ROM, or any other form of computer-readable storage medium well known in the art to which the present invention pertains.

[0065] The components of the present invention may be implemented as a program (or application) stored on a medium for execution in conjunction with a computer, which is hardware. The components of the present invention may be implemented as software programming or software elements. Similarly, embodiments include various algorithms implemented as a combination of data structures, processes, routines, or other programming constructs, and may be implemented in programming or scripting languages ​​such as C, C++, Java, assembler, etc. Functional aspects may be implemented as algorithms executed by one or more processors.

[0066] Although the preferred embodiments of the dual holographic printing apparatus and method according to the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the accompanying drawings, which also belong to the present invention. [Explanation of symbols]

[0067] 111...First laser, 112...Second laser, 113...Third laser, 120...Wave plate (1 / 2λ), 130...Wave plate (1 / 4λ), 141, 142...Dichroic lens, 151-158...Mirror, 161-165...Beam splitter, 171...First automatic ND filter, 172...Second automatic ND filter, 181 , 182···Spatial filter, 191, 192···Collimation lens, 211···First spatial light modulator, 212···Second spatial light modulator, 221···First optical head, 222···Second optical head, 231, 232···Holographic medium, 241···First shutter, 242···Second shutter, 250···Computer

Claims

1. A plurality of lasers exhibiting different wavelengths; a plurality of dichroic lenses and mirrors that combine the beams output from the plurality of lasers into one beam and output it as a white beam; a plurality of beam splitters for splitting the white beam outputted through the plurality of dichroic lenses and mirrors into a beam for sending to a stereogram printing device and a wavefront printing device, respectively, and another beam, and further splitting the other beam to send as a reference beam to the stereogram printing device and the wavefront printing device, respectively; and a computer that controls the stereogram printing device and the wavefront printing device so that a hologram is printed with the beam sent through the beam splitter.

2. The plurality of lasers 10. The dual holographic printing device of claim 1, comprising three lasers, first to third, that output beams of different wavelengths representing R, G, and B, and the first to third lasers output beams of wavelengths of 660 nm, 532 nm, and 473 nm, respectively.

3. 10. The dual holographic printing device of claim 1, further comprising a plurality of acousto-optic modulators disposed in front of the plurality of lasers, the acousto-optic modulators being coupled to and controlled by the computer.

4. the plurality of dichroic lenses are disposed in front of the first and second lasers, respectively, and pass and refract the beams output from the first and second lasers in a specific direction; the mirror is disposed in front of the third laser and reflects the beam output from the third laser in a specific direction; 3. The dual holographic printing device of claim 2, wherein the beams passing through the plurality of dichroic lenses and the beams reflected by the mirror are combined into one beam.

5. The plurality of beam splitters include: a first beam splitter for splitting the beam reflected by the mirror and sending it to the stereogram printing device; a second beam splitter that splits the beam passing through the first beam splitter and sends it to the wavefront printing device; a third beam splitter that splits the beam that has passed through the second beam splitter and sends a reference beam to the stereogram printing device and a reference beam to the wavefront printing device, respectively. The dual holographic printing device of claim 1 , further comprising:

6. The computer 2. The dual holographic printing device of claim 1, wherein a first automatic ND filter and a first shutter of the stereogram printing device and a second automatic ND filter and a second shutter of the wavefront printing device are controlled to perform holographic stereogram printing or holographic wavefront printing.

7. The computer 10. The dual holographic printing device of claim 6, wherein, in order to perform holographic stereogram printing in the first spatial light modulator, a first automatic ND filter of the first and second inactivated automatic ND filters is activated to a maximum value, and an image corresponding to specific coordinates of a hogel, which is an elementary hologram, is displayed while a first shutter of the first and second inactivated shutters is activated, thereby exposing the holographic medium for a specific exposure time.

8. The computer 8. The dual holographic printing device of claim 7, wherein after the holographic medium is exposed for the specific exposure time, the first automatic ND filter and the first shutter are deactivated, and an XY stage is moved to record an elementary hologram at a coordinate next to the specific coordinate.

9. The computer 7. The dual holographic printing device of claim 6, wherein, in order to perform holographic wavefront printing in the second spatial light modulator, the second automatic ND filter of the first and second inactivated automatic ND filters is activated to a maximum value, and an image corresponding to specific coordinates of an elementary hologram is displayed while the second shutter of the first and second inactivated shutters is activated, thereby exposing the holographic medium for a specific exposure time.

10. The computer 10. The dual holographic printing device of claim 9, wherein after the holographic medium is exposed for the specific exposure time, the second spatial light modulator and the second shutter are deactivated, and an XY stage is moved to record an elementary hologram at a coordinate next to the specific coordinate.

11. The computer 7. The dual holographic printing device of claim 6, wherein, in order to perform holographic stereogram printing and holographic wavefront printing in the first and second spatial light modulators, a first automatic ND filter of the first and second inactivated automatic ND filters is activated to a maximum value, and an image corresponding to specific coordinates of an elementary hologram is displayed while a first shutter of the first and second inactivated shutters is activated, thereby exposing the holographic medium for a specific exposure time.

12. The computer 12. The dual holographic printing device of claim 11, wherein after the holographic medium is exposed for the specific exposure time, the first spatial light modulator and the first shutter are deactivated, a second automatic ND filter of the deactivated first and second automatic ND filters is activated to a maximum value, and an image corresponding to specific coordinates of an elementary hologram is displayed while the second shutter of the deactivated first and second shutters is activated, thereby exposing the holographic medium for the specific exposure time.

13. The computer 13. The dual holographic printing device of claim 12, wherein after the holographic medium is exposed for the specific exposure time, the second spatial light modulator and the second shutter are deactivated, and an XY stage is moved to record an elementary hologram at a coordinate next to the specific coordinate.

Images