WO2023003091A1 - Method for duplicating large-area color hologram - Google Patents

Abstract

The present invention relates to a system for duplicating a large-area color hologram, comprising: a light source unit including a laser, a lens, a mirror and an optical shutter so as to form a reference beam and a duplicated beam; a beam relay unit including a mirror, a structure and adjuncts; a recording medium movement unit including a hologram recording medium, an xy-axis movement stage and adjuncts; a master movement unit including a master hologram and a z-axis movement stage; and a control unit for controlling the xy-axis movement stage, the z-axis movement stage and the optical shutter. In addition, the present invention relates to a method for duplicating a large-area color hologram, comprising the steps of: raising an HM to be in close contact with (1,1); exposing a duplicated beam to the hologram recording medium (1,1) and duplicating same; lowering a master hologram to be separated from the hologram recording medium (1,1); moving a glass plate so that a hologram recording medium (1,2) is moved to a duplicate position; and raising the master hologram so that same is in close contact with the hologram recording medium (1,2). The present invention uses the z-axis movement stage so as to dispose the master hologram so that the hologram recording mediums and the master hologram are in close contact with each other, thereby enabling the execution of correct duplication, horizontally disposes the master hologram and the hologram recording mediums and allows a duplicated beam (or reference beam) to be incident from the top to the bottom, thereby quickly reducing rotational vibration and other vibration in the section caused by gravity, and performs small-area duplication MxN times by using a tiling technique while horizontally moving the hologram recording medium by means of xy-axis stages, and thus has the remarkable effect of enabling large-area duplication to be completed.

Description

How to reproduce large-area color holograms

The present invention relates to a method for replicating a large-area color hologram, and more particularly, since the master hologram is placed using a Z-axis moving stage so that the hologram recording medium and the master hologram come into close contact with each other, accurate replication is possible, and the master hologram And since the hologram recording medium is arranged horizontally and the replication beam (or reference beam) is configured so that it is incident from the upper direction to the lower direction, it is possible to quickly reduce rotational vibration and other vibrations of the cross section by gravity, and the XY stage A large-area color hologram copying method capable of completing large-area copying by performing MxN small-area copying by performing small-area copying using a tiling technique while moving a hologram recording medium in a horizontal direction using a hologram recording medium.

Representative glossary of terms described in the present invention A master hologram is an original hologram that has content to be copied.

*Hologram recording medium is a photosensitive material that creates a hologram by being exposed to light or laser light. It is an object that becomes a cloned hologram after the cloning process is over.

The cloning hologram is the result of cloning work. A copy of the master hologram. The original content is transferred to the hologram recording medium.

Holography refers to a technology of recording and reproducing three-dimensional information using the interference of light caused by two laser beams meeting each other, and a hologram refers to a photograph taken with the technology.

Holography can provide a perfect three-dimensional image and is used in various applications such as anti-counterfeiting of credit cards, anti-counterfeiting of software, anti-counterfeiting of banknotes or documents, optical communication, and hologram art.

In recent years, much attention has been focused on the implementation of holographic optical elements (HOE) with optical functions. Since HOE can implement high diffraction efficiency, narrowband frequency characteristics, and various optical functions with one element, It is widely used in HUD (head-up display) for displaying information of airplanes and automobiles, HMD (head mounted display) for augmented reality, and 2D/3D display screens.

Holographic technology is expected to be applied to a wider range of applications in the future.

In order to respond to such diverse application fields and application cases, hologram production and replication technology is essential because mass production and dissemination of holograms are required in the future.

Replicating a hologram means transferring interference information stored in a master hologram (original hologram) to a recording medium.

A hologram is copied by simultaneously irradiating a master hologram and a recording medium with coherent light (usually a laser beam).

A photosensitive recording medium such as photopolymer or silver halide is mainly used as a recording medium.

When a reference beam (replication beam) is incident after bringing the master hologram and the recording medium into or close to each other, hologram replication is performed.

At this time, a collimated beam or a spherical wave close to the collimated beam is mainly used as the replica beam.

As an example of prior patent technology, in Publication No. 10-2021-0046485

Claim 1. Consisting of a light source unit (10), a duplication unit (20), and a moving unit (30), a spatial multiplex beam in which several beams are arranged in a space instead of a single beam is used as a reference beam so that the radiator is applied to the coated object. A hologram duplication system characterized by duplicating is disclosed. In addition, a hologram recording device is disclosed in Registered Patent Publication No. 10-1942975.

1 shows a hologram replication structure.

The hologram replication structure is related to the structure in which the master hologram is produced, and is largely classified into a transmissive type and a reflective type.

Looking at the structural difference between the transmissive type and the reflective type, it can be seen that the arrangement order of the recording medium and the master hologram is reversed based on the incident beam (reference beam or replica beam).

In the transmissive type, the incident beam first passes through the master hologram and then encounters the recording medium, whereas in the reflective type, the incident beam passes through the recording medium first and then encounters the master hologram.

As shown in FIG. 2, hologram duplication technology can be classified into an adhesive type and a non-adhesive type according to the distance or attachment state between the master hologram and the hologram recording medium.

The distance between the master hologram and the recording medium greatly affects the quality of the duplicate hologram, which is the result of hologram duplication.

In the case of adhesive replication, since the master hologram and the hologram recording medium are usually directly bonded, the gap between the two films disappears, so the replication quality of the replica hologram is high.

However, in the case of adhesive duplication, a process of attaching the duplication film to the master hologram and a peeling process are required, and a post-process of transferring the peeled off duplication hologram film to another transparent plate is also essential.

In this process, there is a high risk of damage to the master hologram or duplicate hologram, such as bending, scratching, breakage, or insertion of foreign substances.

In particular, damage or destruction of the master hologram must be avoided in hologram replication.

In addition, the attachable cloning technology inevitably increases the overall cloning time, and requires a large number of master holograms to reduce the time.

Therefore, the adhesive cloning method can be applied to small or small area cloning, but it is not suitable for large scale or large scale cloning.

In the case of the non-adhesive copying method, the master hologram and the hologram recording medium

Since the hologram recording medium is copied by being adjacent to each other without bonding, the copying is repeatedly performed by moving the hologram recording medium.

Therefore, only one master hologram is sufficient, the risk of damage or destruction of the master hologram can be reduced, and mass duplication is possible.

The smaller the gap between the master hologram and the recording medium, the more accurate replication is performed.

However, in the non-adhesive hologram duplication technology, when the master hologram and the recording medium are physically attached (interval = 0), the surface of the master hologram and the recording medium is scratched and damaged due to physical friction when the glass plate (or recording medium) moves. problem arises

However, if the two films are spaced apart to avoid physical friction between the master hologram and the recording medium, it is difficult to clearly reproduce the hologram.

On the other hand, if the master hologram and the hologram recording medium are arranged vertically when constructing the duplication system, there is rotational vibration acting in the direction of the cross section of the master hologram or hologram recording medium. The rotational vibration is large, and the vibration reduction time is also long.

If the master hologram and the hologram recording medium are arranged horizontally, rotational vibration acting in the sectional direction can be reduced, and other vibrations can also be rapidly reduced by gravity.

In the present invention, the reflection type hologram replication is mainly described, but the same can be applied to the transmission type master hologram replication by changing the position of the master hologram and the recording medium.

The smaller the gap between the master hologram and the recording medium, the more accurate replication is performed.

Therefore, it is necessary to make the distance between the master hologram and the recording medium extremely narrow or close so that hologram replication can be performed well.

However, in the non-adhesive hologram duplication technology, when the two films are physically attached (gap = 0), when the glass plate (or recording medium) moves, the surface of the master hologram and the recording medium is scratched and damaged due to physical friction. occurs.

Therefore, in order to avoid damage to the master hologram and the recording medium, it is necessary to widen the gap between the two films.

In summary, the condition that the distance between the master hologram and the recording medium must be narrowed in order to increase the quality of hologram reproduction, and the condition that the distance between the master hologram and the recording medium must be widened to protect the master hologram and the recording medium. necessary.

Accordingly, the present invention intends to suggest a method to solve this problem.

In addition, when the master hologram and the hologram recording medium are arranged vertically when constructing a duplication system, there is rotational vibration acting in the direction of the cross section of the master hologram or hologram recording medium. The rotational vibration is large, and the vibration reduction time is long.

Accordingly, the present invention intends to propose a method capable of quickly reducing rotational vibration and other vibrations of the cross section of a recording medium.

In addition, it is not difficult to design a system capable of performing large-area replication at once, but it is not easy to actually implement the system and perform large-area replication.

Therefore, in the present invention, a large-area hologram replication method and system capable of system implementation are proposed.

The present invention relates to a large-area color hologram replication system, comprising: a light source unit comprising a laser, a lens, a mirror, and an optical shutter to form a reference beam and a replication beam;

a beam relay unit composed of mirrors, structures, and appendages;

a recording medium moving unit composed of a hologram recording medium, an xy-axis moving stage, and accessories;

A master moving unit composed of a master hologram and a z-axis moving stage;

a controller for controlling the xy-axis moving stage, the z-axis moving stage, and the optical shutter; It is characterized by consisting of.

And, the present invention relates to a large-area color hologram replication method,

HM rises and comes into close contact with (1,1);

Steps of exposing the replication beam to the recording medium (1,1) and performing replication:

step of descending the master hologram and separating it from the hologram recording medium (1, 1);

Moving the glass plate to move the hologram recording medium (1, 2) to the copy position;

It is characterized in that it consists of; the step of raising the master hologram and adhering to the hologram recording medium (1, 2).

In addition, the HM rises and adheres to (1,1);

After the hologram recording medium (1,1) is moved to the copy position by the XY-axis moving stage in the state where the optical shutter is blocked, the master hologram is raised by the Z-axis moving stage and adheres to the hologram recording medium (1,1). characterized by being

Therefore, since the present invention arranges the master hologram using the Z-axis moving stage so that the hologram recording medium and the master hologram are in close contact with each other, accurate replication is possible, the master hologram and the hologram recording medium are horizontally arranged, and the copy beam ( Or, since the reference beam) is configured to be incident from the upper direction to the lower direction, it is possible to quickly reduce rotational vibration and other vibrations of the cross section by gravity, and tiling (while moving the hologram recording medium in the horizontal direction using the XY stage) There is a remarkable effect of completing large-area replication by performing small-area replication by performing MxN rounds of small-area replication by performing small-area replication using the tiling technique.

1 is a basic structure of hologram replication. (a) transmissive hologram, (b) reflective hologram, (c) enlarged side view of reflective structure

Figure 2 is a hologram replication structure diagram <(a) attached type, (b) non-adhesive type>

3 is a block diagram of the system of the present invention

4 is a schematic diagram of the operation of the method of the present invention

5 is a flow chart of a hologram replication process according to the method of the present invention

Figure 6a is an optical configuration diagram of the system of the present invention. (a) top view

Figure 6b is an optical configuration diagram of the system of the present invention. (b) side view

7 is a 3D modeling perspective view of the system of the present invention

8 is a master hologram used in the replication experiment of the present invention. (a) white light irradiation, (b) green light laser light irradiation image

9 is a replication experiment result using the replication system of the present invention. (a) duplicate hologram (1,1), (b) 30-inch large-area hologram image

<Description of symbols for main parts of drawings>

10: beam relay unit 20: light source unit

21: laser 22: incident beam

23: incident beam (parallel beam) 24: optical shutter

30: light blocking film 40: master moving unit

41: Master Hologram

50: recording medium moving unit

1: mirror 2; glass

3: recording medium 4: lens

51: xy-axis movement stage 52: z-axis movement stage

3 shows a block diagram of the system of the present invention

The system of the present invention includes a light source unit configured of a laser, a lens, a mirror, an optical shutter, etc. to form a reference beam (replicated beam);

A beam relay unit composed of mirrors, structures, accessories, and the like;

a recording medium moving unit composed of a hologram recording medium, an xy-axis moving stage, and accessories;

a master moving unit composed of a master hologram, a z-axis moving stage, and the like;

a controller for controlling the xy-axis moving stage, the z-axis moving stage, and the optical shutter;

consists of

4 shows the principle of operation of the method of the present invention.

In the present invention, a parallel beam or a spherical wave beam can be used as an incident beam (or a duplicate beam), and the use of a parallel beam will be described as a basic premise.

In order to create a full-color replica hologram, the RGB laser light source is converged through an optical element such as a mirror to form a single laser beam.

The combined RGB light source passes through a shutter, is converted into a plane wave by two lenses, and is directed to a hologram recording medium. Several mirrors and auxiliary structures are used in the middle to illuminate from upward to downward.

The master hologram and hologram recording medium are arranged in a horizontal direction, and since the master hologram and hologram recording medium are film-type materials, they are usually attached or fixed to a transparent plate (glass, acrylic, etc.).

After the master hologram connected to the Z-axis moving stage is brought into close contact with the hologram recording medium, a replica beam is exposed.

When the copy beam is incident, a diffraction beam (acting as an object beam) is generated in the master hologram, and a new hologram identical to the master hologram is recorded (replicated) on the hologram recording medium.

After the replication beam exposure is over, the distance between the master hologram and the hologram recording medium is slightly increased, and then the tiling technique is applied, which moves the hologram recording medium connected to the XY-axis moving stage and repeats replication. As a result, large-area replication is achieved. it becomes possible

The number of tiling is determined according to the size (or area) of the master hologram.

Increasing the size of the master hologram reduces the number of tiling, but duplicates

The quality can be lowered, and the smaller the size of the master hologram is, the better the clone quality is, but the number of tilings increases.

Therefore, a compromise is needed between master hologram size and replica quality.

In the present invention, although the reflection type hologram replication configuration is basically described, the present invention can also be applied to transmission type hologram replication if the positions of the master hologram and the recording medium are exchanged and the optical configuration is changed accordingly.

① HM rises and sticks to (1,1)

After the hologram recording medium (1,1) is moved to the copy position by the XY-axis moving stage in the state where the optical shutter is blocked, the master hologram is raised by the Z-axis moving stage and adheres to the hologram recording medium (1,1). do.

② Expose the replication beam to (1,1) and perform replication

The optical shutter is opened, laser light is irradiated to the hologram recording medium (1,1) and the master hologram, hologram replication of the (1,1) area is performed, and the optical shutter is closed when the exposure time is over.

③ HM descends and separates from (1,1)

The master hologram descends and is separated from the hologram recording medium (1,1).

④ Move (1,2) to the copy position

*The glass plate is moved by one space, and the hologram recording medium (1, 2) is moved to the copy position.

⑤HM adhesion

The master hologram rises and adheres to the hologram recording medium (1, 2).

⑥ Repeat the above process

Figure 6 shows the optical configuration of the system of the present invention, Figure 6 (a) is a top view, Figure 6 (b) is a side view seen from the side.

Three laser beams (R, G, B) are mixed into one beam by an optical element (mirror, dichroic mirror, etc.) to generate a color beam.

One RGB light source passes through the shutter and removes miscellaneous light through two lenses and a spatial filter.

The color beam is converted into a parallel beam through two lenses and a spatial filter, and transmitted to the hologram recording medium through several mirrors.

Replication is performed while the duplicate beam (reference beam) and the diffraction beam (signal beam) diffracted from the master hologram form an interference pattern in the hologram recording medium.

At this time, the master hologram and the hologram recording medium must be in close contact.

When the replication of (1,1) of the hologram recording medium is completed, the Z-axis moving stage operates to separate the master hologram from the recording medium, and the XY-axis moving stage operates to move the hologram recording medium (1,2) to the exposure point. to place

Meanwhile, the opening and closing of the optical shutter and the driving of the Z-axis moving stage and the XY-axis moving stage are automatically controlled by the computer of the control unit.

7 is a 3D modeling picture of the system of the present invention designed using a professional 3D design program.

In FIG. 7, a multi-layered structure in which mirrors can be installed is designed to be disposed around the hologram recording medium so that the copy beam is irradiated from the top to the bottom of the recording medium.

By adjusting the position of the last mirror in the copy beam path, the incidence angle of the copy beam incident on the hologram recording medium can be changed.

8 is a picture of a master hologram used in a replication experiment using the system of the present invention.

8(a) and 8(b) are images of the master hologram observed when irradiating white light and green laser light, respectively.

9 is a photograph of the results of a replication experiment using the replication system of the present invention.

9(a) is a photograph reproduced with a green laser light of a duplicate hologram (1,1).

9(b) is a photograph of a holographic image observed when a projection image is projected onto a 30-inch class large-area hologram (holographic screen) manufactured by a tiling method.

Claims (3)

1. a light source unit 20 composed of a laser 21, a lens 4, a mirror 1, and an optical shutter 24 to form a reference beam and a duplicate beam;

   A beam relay 10 comprising a mirror 1;

   a recording medium moving unit 50 composed of a hologram recording medium 3 and an xy-axis moving stage;

   A master moving unit 40 composed of a master hologram 41 and a z-axis moving stage 52;

   a controller for controlling the xy-axis moving stage 51, the z-axis moving stage 52, and the optical shutter; Large-area color hologram replication system, characterized in that consisting of
2. HM rises and comes into close contact with (1,1);

   Steps of exposing the replication beam to the recording medium (1,1) and performing replication:

   step of separating the master hologram 41 from the hologram recording medium 1,1 by descending;

   Moving the glass plate to move the hologram recording medium (1, 2) to the copy position;

   A large-area color hologram copying method characterized in that it consists of;
3. The method of claim 2, wherein the HM rises and adheres to (1, 1);

   After the hologram recording medium 1,1 is moved to the duplicate position by the XY-axis moving stage 51 in the state where the optical shutter 24 is blocked, the master hologram 41 is moved by the Z-axis moving stage 52. A large-area color hologram copying method characterized in that it rises and adheres to the hologram recording medium (1,1)

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