KR20210058022A - System and method for printing of holographic stereogram using optical fiber - Google Patents

Abstract

Provided are a holographic stereogram printing system using optical fibers and a method thereof. According to an embodiment of the present invention, the holographic stereogram printing system using optical fibers includes: a laser outputting light; a half-wave plate, when the outputted light has passed therethrough, controlling a polarization condition of the light; a coupler collecting the light having passed through the half-wave plate; and a 1x2 polarization-maintain coupler made of optical fibers to lead the light having passed through the coupler to be distributed to an object wave and a reference wave. Accordingly, an optical fiber-based small holographic printer with easy optical alignment can be manufactured. Moreover, a low-cost laser with low output can be used instead of a high-efficiency laser light source used for a holographic printer. Also, since an optical head part which is a core part of a holographic printer can be simplified and lightened, the optical head part can be moved during printing like other existing printers which are commercialized, thereby advancing the commercialization of a holographic printer.

Description

System and method for printing of holographic stereogram using optical fiber

The present invention relates to a holographic stereogram printing system and method, and more particularly, to a holographic stereogram printing system and method using an optical fiber.

Conventional holographic printers using coherent light sources (e.g. lasers) provide 3D images to users without distortion, or have the advantage of being able to easily manufacture specific optical devices. component) complexity, optical path complexity, vast mechanical stage size, the need for a high-efficiency laser for high power, increase of exposure time required for recording holographic recording media caused by a decrease in output power of diffracted light, and There were various problems such as noise of the hologram result due to the vibration problem caused by this.

In particular, the fact that the experimental setup exists on the optical table used in most optical laboratories and the optical path for recording multiple optical elements and diffraction components is complicated, which is the biggest obstacle to the commercialization of holographic printers. Has been.

1 shows an example of an optical setup constituting a conventional holographic printer. As illustrated in FIG. 1, since the optical setup of a holographic printer is composed of a complex optical system, the reason for inefficiency is as follows. First of all, optical alignment based on free-space optics has a vast area occupied by space.

For example, in the case of FIG. 1, a light source from an RGB laser passes through an acoustic optic modulator (AOM) that acts as a shutter, and the light passes through a plurality of lenses, a dichroic mirror, and a polarization beam splitter (PBS). ), it is incident on the desired optical system, so the area occupied spatially along with a large number of optical losses is bound to be large.

Second, in order to record a hologram, the interference pattern of the object wave and the reference wave is recorded in a holographic recording material. In this case, the existing free space is used to distribute the object light and the reference light. An element used in an optical system is a cube-shaped polarized light splitter.

This is because the original amount of light is accurately distributed at 50:50, compared to the reference light (50%), which can be used immediately after being distributed, the object light after passing through multiple optical elements and optical loss due to diffraction (<<50%). For the combination of, the amount of light of the reference light is artificially lowered by using a filter, resulting in a large number of light losses.

Third, the combination of a telecentric lens and a spatial light modulator (SLM) in the optical head, which can be seen as the core of a holographic printer, has considerable weight and requires precise optical alignment. Since it is an essential structure, it is impossible to move it, and therefore, in a normal case, a hologram is recorded using a mechanical stage capable of XY movement.

At this time, as shown in Fig. 2, since the optical alignment is aligned in a direction parallel to the optical table, the mechanical stage is facing in a vertical direction, and there is a possibility that various vibrations due to gravity or external force may occur when moving in the XY direction. It can be a disturbing factor (noise) in recording.

In other words, since the conventional holographic printer is optically aligned based on the free space optical system, the spatially occupied area is vast, making it difficult to manufacture a simple holographic printer, and it is difficult to commercialize it.

In addition, conventional holographic printers require high-power lasers due to optical loss that occurs while passing through the free space optical system, and the polarized light splitter in the free space optical system distributes object light and reference light only by 50:50. A high-efficiency laser is an essential element because a filter that artificially reduces the amount of light of the reference light is required to match the amount of light that is similar to that of the object light that is drastically reduced while passing through the optical element.

In addition, since the optical head, which is the core of a holographic printer, consists of a telecentric lens, a polarized light splitter, and a spatial light modulator, there is a disadvantage that simplification is difficult due to precise optical alignment and heavy weight.

Therefore, it is simpler than the existing optical system, and the ratio of distributing the object light and the reference light can be adjusted freely, so that it is possible to use the light source more efficiently. Search is required.

The present invention was conceived to solve the above problems, and an object of the present invention is to change the existing free space optical system to an optical fiber-based optical system, so that the optical alignment is achieved, and thus it is simpler than the existing optical system, and It is possible to use a light source more efficiently because the ratio of distributing the reference light can be freely adjusted, and thus, a holographic stereogram printing system and method capable of implementing a holographic printer even with a relatively low-efficiency laser are provided.

Another object of the present invention is to provide a holographic stereogram printing system and method capable of simplifying an optical head portion by condensing a light source corresponding to an optical head portion of a holographic printer with an optical fiber.

According to an embodiment of the present invention for achieving the above object, a holographic stereogram printing system using an optical fiber includes: a laser emitting light; When the emitted light passes, a half wave plate for adjusting the polarization state of the passed light; A coupler capable of condensing light passing through the half-wave plate; And a 1x2 polarization-maintain coupler that is made of an optical fiber and distributes light passing through the coupler into an object wave and a reference wave.

In addition, the holographic stereogram printing system using an optical fiber according to an embodiment of the present invention, in order to modulate the object light distributed through a 1x2 polarization maintaining coupler by a spatial light modulator, And a collimator for increasing the vertical size and may further include.

In addition, according to an embodiment of the present invention, a holographic stereogram printing system using an optical fiber includes: a spatial light modulator for modulating object light passing through a collimator through a holographic pattern; A polarization beam splitter through which the modulated object light passes; An aspherical lens into which object light passing through the polarized light splitter is incident; And a plurality of Hogels constituting a holographic recording medium provided for recording a holographic wavefront by interference with the object light passing through the aspherical lens.

In addition, the 1x2 polarization maintaining coupler allows the ratio of the object light passing through the plurality of optical elements to be distributed at a higher ratio than the ratio of the reference light immediately emitted without passing through the optical element, thereby improving light efficiency.

In addition, the 1x2 polarization maintaining coupler has a diameter of the first optical fiber through which the light distributed as the object light passes so that the ratio of the object light is distributed at a higher ratio than the ratio of the reference light. It can be formed larger than the size of the diameter.

In addition, the 1x2 polarization maintaining coupler may be formed such that a ratio of the area size of the first optical fiber and the area size of the second optical fiber is one of 75:25, 90:10, and 99:1.

In addition, the holographic stereogram printing system using an optical fiber according to an embodiment of the present invention, in order to facilitate the expansion of the holographic area, the object light passing through the aspherical lens is interfered by the reference light and modulated final modulated light. It may further include an optical fiber head (Fiber collimation head) for condensing.

In addition, each Hogel may be divided into a plurality of sub Hogels so that a holographic wavefront of a color corresponding to each divided sub Hogel may be individually recorded.

In addition, a holographic stereogram printing system using an optical fiber according to an embodiment of the present invention further includes an acoustic optic modulator that is provided between the half-wave plate and the coupler and controls the transmission of light passing through the half-wave plate. can do.

On the other hand, according to another embodiment of the present invention, a holographic stereogram printing method using an optical fiber includes the steps of emitting light through a laser; Adjusting a polarization state of light while the emitted light passes through a half wave plate; Condensing light passing through the half-wave plate through a coupler; And distributing the light passing through the coupler into an object wave and a reference wave through a 1x2 polarization-maintain coupler made of an optical fiber.

And according to another embodiment of the present invention, a holographic stereogram printing system using an optical fiber includes a laser emitting light; When the emitted light passes, a half wave plate for adjusting the polarization state of the passed light; A coupler capable of condensing light passing through the half-wave plate; And optical fiber, so that the light that has passed through the coupler is distributed as an object wave and a reference wave, but the ratio of the object light passing through the plurality of optical elements does not pass through the optical elements, but is emitted directly. It includes a 1x2 polarization-maintain coupler that distributes at a higher ratio than that of the 1x2 polarization-maintain coupler.

In addition, according to another embodiment of the present invention, a holographic stereogram printing method using an optical fiber includes the steps of emitting light through a laser; Adjusting a polarization state of light while the emitted light passes through a half wave plate; Condensing light passing through the half-wave plate through a coupler; And distributing the light passing through the coupler into an object wave and a reference wave through a 1x2 polarization-maintain coupler made of an optical fiber. In the step, the ratio of the object light passing through the plurality of optical elements may be distributed at a higher ratio than the ratio of the reference light immediately emitted without passing through the optical element.

As described above, according to the embodiments of the present invention, it is possible to manufacture a small holographic printer based on optical fibers that facilitates optical alignment.

In addition, according to embodiments of the present invention, it is possible to utilize a low-cost laser having a low output instead of a high-efficiency laser light source used in a holographic printer.

In addition, according to embodiments of the present invention, since the optical head, which is a core part of a holographic printer, can be simplified while reducing the weight, it is possible to print while moving the optical head like other commercially available printers. Can accelerate the commercialization of

1 is a diagram illustrating a basic optical setup of a conventional holographic printer,
2 is a diagram illustrating a mechanical stage and an optical head of a conventional holographic printer;
3 is a diagram provided to explain a holographic stereogram printing system using an optical fiber according to an embodiment of the present invention;
4 is a diagram illustrating a state in which an optical fiber head is additionally provided in a holographic stereogram printing system using an optical fiber according to an embodiment of the present invention, and
5 is a flowchart provided to explain a holographic stereogram printing method using an optical fiber according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

3 is a diagram provided for explanation of a holographic stereogram printing system using an optical fiber according to an embodiment of the present invention (hereinafter, referred to as a'holographic stereogram printing system').

The holographic stereogram printing system according to the present embodiment is simpler than the existing optical system because optical alignment is achieved by changing the existing free space optical system to an optical fiber-based optical system. ), it is possible to freely adjust the distribution ratio, so that the light source can be used more efficiently, and thus a holographic printer can be implemented even with a relatively low-efficiency laser 110.

To this end, the holographic stereogram printing system includes a laser 110, a half-wave plate 120, an acoustic optical device 125, a coupler 130, a 1x2 polarization maintaining coupler 140, a collimator 150, and a mirror 155. ), a polarized light splitter 160, a spatial light modulator 170, an aspherical lens 175, and a plurality of Hogels 210.

The laser 110 is a coherent light source and can emit light, and the half-wave plate 120 can adjust the polarization state of the passed light when the emitted light passes.

In addition, the acoustic optical device 125 is provided between the half-wave plate 120 and the coupler 130, and can serve as a shutter for controlling the transmission of light passing through the half-wave plate 120, and the coupler 130 is Light that has passed through the floor plate 120 may be condensed.

In addition, the 1x2 polarization maintaining coupler 140 is made of an optical fiber, so that the light passing through the coupler 130 is distributed as object light and reference light.

Specifically, when passing through the half-wave plate 120 and the acoustic optical element 125 from the coherent light source laser 110 and passing through the coupler 130 capable of condensing light into an optical fiber, the 1x2 polarization maintaining coupler 140 The first optical fiber 141 corresponding to the green portion of FIG. 3 may be distributed as object light, and the second optical fiber 142 corresponding to the red portion may be distributed as reference light.

In the existing free space optical system, the polarization light splitter 160 can distribute only in a ratio of 50:50, but the 1x2 polarization maintaining coupler 140, the ratio of the object light passing through the plurality of optical elements does not pass through the optical element. By distributing at a higher ratio than the ratio of the immediately emitted reference light, the light efficiency can be improved.

This is, if the object light and the reference light are distributed by 50:50, after the object light is distributed through the 1x2 polarization maintaining coupler 140, the collimator 150, the spatial light modulator 170, the polarized light splitter 160 and the aspherical surface This is because while the amount of light decreases in the process of passing through the lens 175, the reference light is distributed through the 1x2 polarization maintaining coupler 140 and immediately emitted, so that the amount of light may be higher than that of the object light.

For example, the 1x2 polarization maintaining coupler 140 has a diameter size of the first optical fiber 141 through which light distributed as object light passes so that the ratio of object light is distributed at a higher ratio than the ratio of reference light. It may be formed larger than the diameter of the second optical fiber 142 through which light passes.

Specifically, the 1x2 polarization maintaining coupler 140, so that the ratio of the area size of the first optical fiber 141 and the area size of the second optical fiber 142 is any one of 75:25, 90:10, and 99:1. Can be formed.

The collimator 150 may increase the horizontal and vertical size of the object light so that the object light distributed through the 1x2 polarization maintaining coupler 140 is modulated by the spatial light modulator 170.

The spatial light modulator 170 may modulate the object light passing through the collimator 150 through a holographic pattern.

The plurality of Hogels 210 constitute a holographic recording medium 200 provided in order to record a holographic wavefront for an object to be recorded because object light passing through the aspherical lens 175 is interfered by the reference light. In addition, each Hogel 210 may be divided into a plurality of sub Hogels 210 so that a holographic wavefront of a color corresponding to each of the divided sub Hogels 210 is individually recorded.

The object light is modulated using the hologram pattern of the spatial light modulator 170 through a collimator 150 that increases the horizontal and vertical size of the light so that it can be modulated by the spatial light modulator 170, and the polarized light splitter 160 After passing through the aspherical lens 175, the hologram is recorded by interfering with the reference light.

Through this, the holographic stereogram printing system according to the present embodiment uses an optical fiber system, so that optical alignment is simple while having spatial efficiency compared to the existing free space optical system, and the use of the 1x2 polarization maintaining coupler 140 Therefore, there is an advantage that the ratio of light distribution can be adjusted.

In addition, the holographic stereogram printing system according to the present embodiment can use a relatively low-power laser 110 for the laser 110 used as a light source, and the advantages of spatial efficiency and light alignment are simple. It can solve the noise problem that occurs.

4 is a diagram illustrating a state in which an optical fiber head 180 is additionally provided in a holographic stereogram printing system according to an embodiment of the present invention.

Referring to FIG. 4, in the conventional holographic printer, the optical head portion, that is, a series of portions that pass through the aspherical lens 175 after being modulated through the spatial light modulator 170, have complex optical alignment and high weight. Because the movement of the printer is inconvenient, the recording head operated in a commercial printer does not move and the stage moves. However, the holographic stereogram printing system according to the present embodiment uses a light source corresponding to the optical head of the holographic printer to an optical fiber. By condensing with, the optical head portion can be simplified.

To this end, the holographic stereogram printing system according to the present embodiment includes the above-described laser 110, half-wave plate 120, acoustic optical device 125, coupler 130, 1x2 polarization maintaining coupler 140, collimator ( In addition to 150), the mirror 155, the polarized light splitter 160, the spatial light modulator 170, the aspherical lens 175, and the plurality of Hogels 210, an optical fiber head 180 may be further included.

The optical fiber head 180 can condense the final modulated light modulated by interference of the object light passing through the aspherical lens 175 by the reference light so as to facilitate the expansion of the holographic area, through which the final modulation can be more easily modulated. Since light can be handled, a holographic area capable of recording a holographic wavefront can be expanded, thereby helping to implement a large-area holographic printer.

That is, the present holographic stereogram printing system has an advantage that the modulated final light is condensed back into an optical fiber as shown in FIG. 4 to facilitate handling of the final modulated light, and thus can have an advantage in expanding to a large area holographic printer.

5 is a flowchart provided to explain a holographic stereogram printing method using an optical fiber according to an embodiment of the present invention.

5, in the holographic stereogram printing method using an optical fiber according to an embodiment of the present invention, when light is emitted through the laser 110 (S510), the emitted light passes through the half-wave plate 120. In the process, the polarization state of light may be adjusted (S520).

In addition, the light passing through the half-wave plate 120 is condensed through the coupler 130 (S530), and the condensed light may be distributed as object light and reference light through a 1x2 polarization maintaining coupler 130 made of an optical fiber. (S540).

Specifically, as described above, when passing through the half-wave plate 120 and the acoustic optical element 125 from the laser 110, which is a coherent light source, through the coupler 130 capable of condensing light into an optical fiber, a 1x2 polarization maintaining coupler ( Through 140 ), the first optical fiber 141 corresponding to the green portion of FIG. 3 may be distributed as object light, and the second optical fiber 142 corresponding to the red portion may be distributed as reference light.

In this case, the 1x2 polarization maintaining coupler 140 allows the ratio of the object light passing through the plurality of optical devices to be distributed at a higher ratio than the ratio of the reference light immediately emitted without passing through the optical device, thereby improving light efficiency.

Meanwhile, the object light can be increased in horizontal and vertical sizes through the collimator 150 (S550), and the object light passing through the collimator 150 is modulated according to a holographic pattern (S560), and a polarized light splitter ( 160) can be passed (S570).

In addition, when the object light passing through the polarized light splitter 160 enters the aspherical lens 175 (S580), the holographic wavefront for the object to be recorded may be recorded due to interference by the reference light (S590).

In the above, preferred embodiments of the present invention have been illustrated and described, but the present invention is not limited to the specific embodiments described above, and the present invention is generally in the technical field to which the present invention belongs without departing from the gist of the present invention claimed in the claims. Various modifications are possible by those skilled in the art of course, and these modifications should not be individually understood from the technical idea or perspective of the present invention.

110: Laser
120: Half wave plate
125: Acoustic optic modulator
130: Coupler
140: 1x2 Polarization-maintain Coupler
141: first optical fiber
142: second optical fiber
150: Collimator (Large beam collimator)
155: Mirror
160: Polarization beam splitter
170: Spatial light modulator
175: Aspheric lens
180: Fiber collimation head
200: Holographic material
210: Printed hogel

Claims (12)

A laser emitting light;
When the emitted light passes, a half wave plate for adjusting the polarization state of the passed light;
A coupler capable of condensing light passing through the half-wave plate; And
Holographic stereogram printing using an optical fiber including a 1x2 polarization-maintain coupler that is made of an optical fiber and distributes the light passing through the coupler into an object wave and a reference wave. system.
The method according to claim 1,
In order to modulate the object light distributed through the 1x2 polarization maintaining coupler by a spatial light modulator, a collimator that increases the horizontal and vertical size of the object light; Holographic stereogram printing system.
The method according to claim 2,
A spatial light modulator for modulating object light passing through the collimator through a holographic pattern;
A polarization beam splitter through which the modulated object light passes;
An aspherical lens into which object light passing through the polarized light splitter is incident; And
A holographic stereogram printing system using an optical fiber further comprising a; a plurality of Hogels constituting a hologram recording medium provided for recording a holographic wavefront by interference with the object light passing through the aspherical lens by the reference light.
The method of claim 3,
The 1x2 polarization maintaining coupler,
A holographic stereogram printing system using an optical fiber, characterized in that the optical efficiency is improved by distributing the ratio of the object light passing through the plurality of optical elements at a ratio higher than the ratio of the reference light immediately emitted without passing through the optical element.
The method of claim 4,
The 1x2 polarization maintaining coupler,
The diameter of the first optical fiber through which the light distributed as the object light passes is larger than the diameter of the second optical fiber through which the light distributed as the reference light passes so that the ratio of the object light is distributed at a higher ratio than the ratio of the reference light. Holographic stereogram printing system using optical fiber.
The method of claim 5,
The 1x2 polarization maintaining coupler,
A holographic stereogram printing system using an optical fiber, characterized in that the ratio of the area size of the first optical fiber and the area size of the second optical fiber is formed to be any one of 75:25, 90:10, and 99:1.
The method of claim 4,
Holo using an optical fiber, characterized in that it further comprises a fiber collimation head for condensing the final modulated light modulated by interference of the object light passing through the aspherical lens by the reference light so as to facilitate the expansion of the holographic area. Graphic stereogram printing system.
The method of claim 4,
Each Hogel,
A holographic stereogram printing system using an optical fiber, characterized in that it is divided into a plurality of sub-hogels so that a holographic wavefront of a color corresponding to each divided sub-hogel is individually recorded.
The method according to claim 1,
A holographic stereogram printing system using an optical fiber, further comprising: an acoustic optic modulator that is provided between the half-wave plate and the coupler and controls the transmission of light passing through the half-wave plate.
Emitting light through a laser;
Adjusting a polarization state of light while the emitted light passes through a half wave plate;
Condensing light passing through the half-wave plate through a coupler; And
Through a 1x2 polarization-maintain coupler made of an optical fiber, the step of distributing the light passing through the coupler into an object wave and a reference wave; holographic stereo using an optical fiber including Gram printing method.
A laser emitting light;
When the emitted light passes, a half wave plate for adjusting the polarization state of the passed light;
A coupler capable of condensing light passing through the half-wave plate; And
It is made of optical fiber, so that the light that has passed through the coupler is distributed as an object wave and a reference wave, but the ratio of the object light passing through a plurality of optical elements is the ratio of the reference light that is directly emitted without passing through the optical element. A holographic stereogram printing system using an optical fiber including a 1x2 polarization-maintain coupler that distributes at a higher ratio than the ratio.
Emitting light through a laser;
Adjusting a polarization state of light while the emitted light passes through a half wave plate;
Condensing light passing through the half-wave plate through a coupler; And
Including; through a 1x2 polarization-maintain coupler (1x2 Polarization-maintain Coupler) made of an optical fiber, distributing the light passing through the coupler into an object wave and a reference wave; including,
The dispensing stage is,
A holographic stereogram printing method using an optical fiber, characterized in that the ratio of the object light passing through the plurality of optical elements is distributed at a higher ratio than the ratio of the reference light immediately emitted without passing through the optical element.

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