KR20230102059A - Hologram optical system - Google Patents

Abstract

The present invention relates to a hologram optical system, wherein the hologram optical system is composed of a light source and one or more lenses, and a lighting unit for collimating light output from the light source and radiating it as parallel light, and a light path of the parallel light emitted from the lighting unit. a display panel for displaying an interference pattern for realizing a CGH image, wherein the parallel light emitted from the lighting unit passes through or is reflected from the interference pattern, and a direction in which the light of the CGH image travels and a projection unit disposed on and projecting an image based on the image generated by the CGH image.

Description

Hologram optical system {HOLOGRAM OPTICAL SYSTEM}

The present invention relates to a hologram optical system, and more particularly, to a digital hologram optical system for projecting a hologram image and adjusting a distance at which a hologram image is output.

A hologram is a technology that depicts a three-dimensional object on a two-dimensional plane with laser beams.

Such a hologram may be implemented in an analog method and a digital method, respectively.

In the case of the analog method, hologram information, which is the recording information of light generated by the interference effect of one or a plurality of laser beams, is stored in a hologram recording object such as photopolymer or silver halide. The dimensional image is seen as a holographic image.

In this way, in order to record hologram information on a recording object, a reference beam and an object beam are required, and an interference pattern generated by interference between the reference beam and the object beam is recorded as hologram information on a corresponding hologram recording medium. .

In this case, the reference light refers to light output from an arbitrary light source and directly irradiated onto the hologram recording medium, and the object light refers to light output from a light source and reflected by an object corresponding to a holographic image.

Eventually, a pattern is formed on the hologram recording medium by the interference of reference light and object light, and this is recorded as hologram information.

Therefore, when reproduction light, which is light of the same wavelength as the reference light used to record hologram information, is irradiated to the hologram recording medium in the direction opposite to the incident direction of the reference light, the hologram information stored in the hologram recording medium is output as an image to the focal plane. will be attached to

On the other hand, in the case of a hologram using a digital method, a special pattern, that is, an interference pattern, is created using pixels of a display panel using CGH (computer generated hologram) technology through mathematical calculation and processing, By recording data on this interference pattern, a three-dimensional (3D) image can be reproduced.

Accordingly, a 3D hologram image can be output using the interference fringes caused by the diffraction phenomenon occurring when the light emitted from the light source passes through the interference fringes and the interference phenomenon generated at the location where the diffracted light meets each other.

Republic of Korea Patent Publication No. 10-2009-0088053 (published date: August 19, 2009, title of invention: digital hologram noise removal method) Republic of Korea Patent Registration No. 10-2277096 (Public date: July 15, 2021, title of invention: method for generating digital hologram using artificial intelligence and deep learning technology)

An object to be solved by the present invention is to remove DC noise generated when reproducing a holographic image.

Another problem to be solved by the present invention is to change the projection distance of a holographic image.

A hologram optical system according to one feature of the present invention is composed of a light source and one or more lenses, and is disposed on a light path of the parallel light emitted from the lighting unit, a lighting unit that collimates the light output from the light source and irradiates it as parallel light, A display panel displaying an interference pattern for realizing a CGH image - Parallel light irradiated from the lighting unit passes through or is reflected from the interference pattern - and is disposed in the direction in which the light of the CGH image travels, and the CGH A projection unit for projecting an image based on an image generated by the image is included.

The hologram optical system according to the above characteristics is located between the lighting unit and the display panel, transmits parallel light irradiated by the lighting unit to the display panel, and reflects the light of the CGH image generated by the display panel to the lighting unit. It may further include a prism that transmits to an optical path different from that of the light path, and the projecting unit may receive light transmitted to the other optical path and project it.

The parallel light passing through the prism may be reflected from an interference pattern of the display panel and may be incident to the prism.

The lighting unit may be positioned on the light path in an opposite direction to the projection unit with respect to the display panel, and parallel light emitted from the lighting unit may pass through the interference pattern and be incident to the projection unit.

The display panel may display different interference patterns so that the position of the image generated by the CGH image is changed along the direction of the light path, and the projection position of the CGH image projected through the projector is changed according to the position of the image. can be changed.

The projection unit may include a plurality of lenses, and the hologram optical system moves the positions of the plurality of lenses on the optical path and directs some of the lenses in the optical path with respect to the remaining lenses. It is possible to change the focal position of an image projected through the projection unit by moving along the projection unit.

The hologram optical system according to the above feature blocks DC noise by being disposed at a position where DC noise that passes through or is reflected from the interference pattern is focused without being diffracted by the interference pattern displayed on the display panel. More filters may be included.

The noise filter may include a blocking portion to block non-diffracted light focused on an optical axis and an opening to pass diffracted light focused off an optical axis.

The opening may have a half-moon shape.

According to this feature, the projection position of the holographic image projected from the projection unit can be changed by adjusting the position where the image of the CGH image generated by the interference pattern is formed while the positions of the display panel and the projection unit are fixed.

As a result, it is possible to adjust the projection state of the finally projected hologram without changing the physical structure of the hologram optical system, so that user convenience can be improved.

In addition, since DC noise, which is diffracted light included in the holographic image, is removed by the noise filter, the quality of the output holographic image can be greatly improved.

1 is a schematic diagram of a hologram optical system according to an embodiment of the present invention.
2 is a diagram conceptually showing a projection distance according to a position of an image formed on a display panel in a hologram optical system according to an embodiment of the present invention.
3 is a conceptual diagram of removing DC noise caused by non-diffracted light using a noise filter in a holographic optical system according to an embodiment of the present invention.
4 is a plan view of a noise filter in a holographic optical system according to an embodiment of the present invention.
5 is a schematic diagram of a hologram optical system according to another embodiment of the present invention.

Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the accompanying drawings, but the same or similar elements are given the same reference numerals regardless of reference numerals, and redundant description thereof will be omitted. In addition, in describing the embodiments disclosed in this specification, if it is determined that a detailed description of a related known technology may obscure the gist of the embodiment disclosed in this specification, the detailed description thereof will be omitted.

Terms including ordinal numbers, such as first and second, may be used to describe various components, but the components are not limited by the terms. These terms are only used for the purpose of distinguishing one component from another.

Singular expressions include plural expressions unless the context clearly dictates otherwise.

In this application, each step described can be performed regardless of the listed order, except for the case where it must be performed in the listed order due to a special causal relationship.

In this application, terms such as "comprise" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Hereinafter, a hologram optical system according to an embodiment of the present invention will be described with reference to the accompanying drawings.

First, referring to FIG. 1, a hologram optical system 1 according to an embodiment of the present invention will be described.

As shown in FIG. 1, the hologram optical system 1 of this example includes a lighting unit 10, a prism 20 positioned on a light path of the lighting unit 10, and a display panel positioned facing one surface of the prism 20. (30) and a projection unit (40) positioned to face the other surface of the prism (20).

The lighting unit 10 includes a light source 11 that outputs light, and at least one lens 12 or 13 that adjusts the focus of the light output from the light source 11 and outputs the light as parallel light by collimating the light. can be provided

At this time, the light source may be a laser light source that outputs a laser, and the lenses 12 and 13 include a plano-convex lens 12 and a collimation lens 13 for adjusting the focus. can do.

The prism 20 may be positioned between the lighting unit 10 and the display panel 30 .

The prism 20 of the present example transfers parallel light irradiated from the lighting unit 10 to the display panel 30 and directs light of an image (ie, CGH image) output from the display panel 30 toward the projection unit 40. That is, it can be reflected in a direction different from the direction in which the lighting unit 10 and the display panel 30 are located.

Accordingly, the prism 20 transmits the light irradiated from the lighting unit 10 and outputs it to one side and reflects the light irradiated from the display panel 30 and outputs it to the other side.

This prism may be a polarization beam splitter (PBS) prism.

The display panel 30 may be a display panel used in a micro display.

The display panel 30 may be disposed on a path of light irradiated from the lighting unit 10, that is, parallel light, and may include a plurality of pixels.

The display panel 30 may display an interference pattern for realizing a CGH image using a plurality of pixels under the control of a controller (not shown).

Therefore, as shown in FIG. 1, the parallel light emitted from the lighting unit 10 may be reflected from the interference pattern and incident toward the prism 20, then reflected by the prism 20 and incident toward the projection unit 40. there is. That is, the light path is changed by the prism 20 located between the lighting unit 10 and the display panel 30, so that the direction (ie, path) of the light of the CGH image can be changed as needed.

As shown in FIG. 1, the projection unit 40 may be disposed in the direction in which the light of the CGH image reflected by the prism 20 travels, and projects an image based on the image generated from the CGH image to the corresponding location. can do.

The projector 40 may include a plurality of lenses 41 and a noise filter 42 for removing DC noise.

The plurality of lenses 41 may include a plano-concave lens and a plano-convex lens.

The noise filter 42 may be positioned on the optical axis OP1 , which is the axis of light incident to the projection unit 40 , and may be directly generated from the interference pattern without being diffracted by, for example, the interference pattern displayed on the display panel 30 . It is disposed at a position where the reflected light (ie, DC noise) is focused, so that the DC noise can be blocked from being projected to the projection position.

The light incident to the projector 40 may be divided into non-diffracted light and diffracted light, and thus, the light path is a non-diffracted path RA1 through which non-diffracted light travels and a diffraction path RA2 through which diffracted light travels. ) may exist.

In this case, the focal point may be located on the optical axis OP1 and may be a portion where non-diffracted light is focused.

As already described, the CGH image uses the diffraction and interference phenomena of light passing through the interference pattern on the display panel 30, and the light corresponding to the CGH image is diffracted light and may be light deviating from the optical axis OP1. .

Therefore, CGH light normally incident to the projection unit 40 is light outside the optical axis OP1, but non-diffracted light that is not diffracted and focused on the optical axis OP1 can also be incident to the projection unit 40. In this case, the quality of the holographic image output through the projection unit 40 is adversely affected.

However, in the present example, the noise filter 42 may be placed at the position of the optical axis where the non-diffracted light is focused to prevent the noise component, which is the non-diffracted light, from being finally output through the projection unit 40 .

Accordingly, the noise filter 42 may be disposed at a position of the optical axis OP1 where the DC noise is focused to block the DC noise.

As shown in FIG. 4, the noise filter 42 may have a circular planar shape, and may include a half-moon-shaped opening 421 and a blocking portion 422 adjacent to the opening 421 and closed. can

As a result, the opening 421 may be a portion of the blocking portion 422 opened in a half-moon shape.

Therefore, since the light reaching the opening 421 can pass through the opening 421 and be emitted to the rear end, in this example, the opening 421 corresponds to the path of the diffracted light focused at a position off the optical axis OP1. can be positioned appropriately.

In this example, the blocking portion 422 is a portion for blocking light passing through the optical axis OP1, that is, non-diffracted light. It may be positioned to correspond to the focus position of OP1).

The blocking portion 422 is to prevent transmission of non-diffracted light and may be made of a material that does not transmit light.

In this way, the projector 40 of the present example receives the light of the CGH image reflected by the prism 20 and projects only the diffracted light to the corresponding position so that the CGH image can be output as a holographic image.

At this time, the position of the projection unit 40, the type of lens 41 in the projection unit 40, and the distance between the lenses 41 may be fixed or changed as needed.

For example, in the case of a digital hologram, the position where the CGH image is formed by the interference pattern displayed on the display panel 30 may be changed along the traveling direction of light while the position of the display panel 30 is fixed without moving. can

To this end, as an example, since the control unit can change the position where the CGH image is formed by controlling the calculation formula of the interference pattern displayed on the display panel 30, the position of the display panel 30 is used by using such a CGH image reproduction technology. In a fixed state, the projection position of the projection unit 40 and the focal position of the light passing through the projection unit 40 can be adjusted by adjusting the position where the CGH image is formed without a mechanical focusing device.

Accordingly, as shown in FIG. 2 , the position of the holographic image projected through the transmission unit 40 may also be changed according to the position where the image of the CGH image is formed.

Referring to FIG. 2 , in a state in which the position of the display panel 30 is fixed at a certain point, a CGH image may be imaged at three locations (IM1, IM2, and IM3), for example, under control of a controller or the like. In this case, the position where the image is formed may be formed not only on the front side (eg, IM2 and IM3) of the display panel 30 but also on the rear side (eg, IM1).

In this way, since the position where the CGH image is formed varies according to the state of the interference pattern displayed on the display panel 30, the projection position of the CGH image projected through the projection unit 40 may also vary according to each corresponding position. there is.

As shown in FIG. 2 , the projection position corresponding to the CGH image IM1 formed on the rear side of the display panel 30 is the projection position since the projection position may also become farther away from the front of the display panel 30 as the position where the image is formed is farther away from the front of the display panel 30. is closest to the projector 40 (IM11), and a projection position corresponding to the CGH image IM3 formed farthest from the bottom of the display panel 30 may be the farthest from the projector 40 (IM31).

In this way, it is possible to substantially adjust the projected position of the holographic image for the CGH image without adjusting the positions of the display panel 30 and the projection unit 40 and without changing the focus position of the projection unit 40. can

However, unlike this, in an alternative example, the projection position of the holographic image for the CGH image is changed by changing the state of the projection unit 40, such as the position of the projection unit 40 and the distance between the lenses in the projection unit 40. can be changed

In this case, the position of the display panel 30 may be fixed, and the interference pattern displayed on the display panel 30 may also be fixed. Accordingly, the location where the image of the CGH image is formed by the interference pattern of the display panel 30 may also be fixed to a certain point.

In this way, in a state where an image (eg, IM2) is formed at a certain location, the lens 41 and the noise filter 42 located in the projection unit 40 along the position of the projection unit 40, that is, along the light path, By adjusting, the position (IM11, IM21 or IM31) of the holographic image that is actually projected may be changed.

At this time, the position of the projected holographic image can be changed by adjusting the position of the projection unit 40 by moving the positions of all the lenses 41 in the projection unit 40 along the light path.

In addition, by moving some of the lenses 41 in the projection unit 40 along the direction of the light path with respect to the other lenses to adjust the distance between some of the lenses 41 along the direction of the light path, the focal point of the projected holographic image The position is adjusted so that the image quality can be improved.

Next, referring to FIG. 5, a hologram optical system 1a according to another embodiment of the present example will be described.

In comparison with FIG. 1, the same reference numerals as in FIG. 1 are assigned to components having the same structure and performing the same functions, and detailed descriptions thereof may also be omitted.

As shown in FIG. 5 , the hologram optical system 1a of this example includes a light source unit 10, a display panel 30 located on a light path in front of the light source unit 10, and a projection unit located in front of the display panel 30 ( 40) may be provided.

In this way, in the hologram optical system 1a of this example, unlike the case of FIG. 1, the prism for changing the light path can be omitted.

Therefore, the light source unit 10, the display panel 30, and the projection unit 40 are positioned on the same light path, so that the light output from the light source unit 10 can pass through the interference pattern displayed on the display panel 30. .

In this way, when light is irradiated on the interference pattern of the display panel 30, an image of the CGH image corresponding to the interference pattern displayed on the display panel 30 can be focused on the corresponding position, and the light for this image can be projected on the same optical path. It may be incident toward the projection unit 40 located on the image.

Therefore, a holographic image corresponding to the CGH image may be projected and output at a location determined according to the location of the image on the CGH image and the structure of the projection unit 40 (eg, device location and internal lens structure).

In this way, since the prism for changing the light path is omitted in the hologram optical system 1a of this example, the lighting unit 10 and the projection unit 40 are positioned in opposite directions with the display panel 30 positioned in the middle therebetween. As a result, light (eg, parallel light) output from the light source unit 10 may be directly incident to the display panel 30 without changing a path and pass through the interference pattern.

In this way, since the prism for changing the light path is omitted and the display panel 30 does not need to include a separate reflector for reflecting the light passing through the prism back toward the prism, the manufacturing cost of the hologram optical system 1a and Weight may be reduced.

Even in the case of such a holographic optical system 1a, as described with reference to FIGS. 1 and 2 , the holographic image is projected by adjusting the position where the CGH image is formed while the display panel 30 and the projection unit 40 are fixed. The projection position of the holographic image may be changed by changing the position or by adjusting the position of the projection unit 40 and the distance between some lenses inside the projection unit 40 .

The technical features disclosed in each embodiment of the present invention are not limited to the corresponding embodiment, and unless incompatible with each other, the technical features disclosed in each embodiment may be merged and applied to other embodiments.

Therefore, in each embodiment, each technical feature is mainly described, but each technical feature may be merged and applied to each other unless incompatible with each other.

The present invention is not limited to the above-described embodiments and accompanying drawings, and various modifications and variations will be possible from the viewpoint of those skilled in the art to which the present invention belongs. Therefore, the scope of the present invention should be defined by not only the claims of this specification but also those equivalent to these claims.

1, 1a: hologram optical system 10: lighting unit
11: light source 12, 41: lens
20: prism 30: display panel
40: projection unit 42: noise filter
421: opening 422: blocking portion

Claims (9)

a lighting unit composed of a light source and one or more lenses to collimate the light output from the light source and irradiate it as parallel light;
a display panel disposed on an optical path of the parallel light emitted from the lighting unit and displaying an interference pattern for realizing a CGH image, wherein the parallel light emitted from the lighting unit passes through the interference pattern or is reflected from the interference pattern; and
A projector that is disposed in the direction in which the light of the CGH image travels and projects an image based on the image generated by the CGH image.
A holographic optical system comprising a. According to claim 1,
Located between the lighting unit and the display panel, the parallel light irradiated by the lighting unit is transmitted to the display panel, and the light of the CGH image generated by the display panel is reflected to a light path different from that of the lighting unit. prism to transmit
Including more,
The projection unit receives and projects the light transmitted through the other optical path. According to claim 2,
The hologram optical system of claim 1 , wherein the collimated light passing through the prism is reflected from an interference pattern of the display panel and incident to the prism. According to claim 1,
The hologram optical system of claim 1 , wherein the lighting unit is positioned on the light path in an opposite direction to the projector with respect to the display panel, and parallel light emitted from the lighting unit passes through the interference pattern and is incident to the projector. According to claim 1,
The display panel displays different interference patterns so that the position of the image generated from the CGH image is changed along the direction of the light path;
A hologram optical system in which a projection position of a CGH image projected through the projector is changed according to the position of the image. According to claim 1,
The projection unit includes a plurality of lenses,
The hologram optical system moves the positions of the plurality of lenses on the optical path, and moves some of the plurality of lenses along the direction of the optical path with respect to the remaining lenses, so that the image projected through the projector A holographic optical system that changes the focal position. According to claim 1,
A noise filter that blocks DC noise by being disposed at a position where DC noise that is not diffracted by the interference pattern displayed on the display panel but passes through the interference pattern or is reflected from the interference pattern is focused.
A holographic optical system further comprising a. According to claim 7,
The noise filter includes a blocking portion for blocking non-diffracted light focused on an optical axis and an opening for passing diffracted light focused on an off-axis location. According to claim 8,
The opening is a half-moon shape holographic optical system.

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