CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage Patent Application of PCT International Patent Application No. PCT/KR2016/011750 (filed on Oct. 19, 2016) under 35 U.S.C. § 371, the teaching of which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

The present invention relates to a refractive optical screen, and a floating hologram system using the same.

BACKGROUND ART

Holography means a technology of recording and reproducing three-dimensional information by using a light interference phenomenon generated when two laser beams meet. A hologram is a word created by combining “holo” meaning “perfectness” or “whole” and “gram” meaning a “message” or “information”. The hologram is being studied as a next-generation imaging technology because the hologram provides a 3D effect that look like a real object.

However, in order to record, reproduce, and display a hologram, a small optical device enough to cause diffraction and interference of light and data processing capability are required, so that it is considered to take a long time to commercialize the hologram.

Recently, a hologram theater for directing as if an actual person appears and performs on the stage by using an optical illusion effect known as “Pepper's ghost” has been created.

In general, every medium has reflectivity and transmittance, and “Pepper's ghost” means a technique for enabling a person to view transmitted light of a rear surface of a material and reflected light of a front surface of the material at the same time by gloss coating a material, such as polyethylene terephthalate (PET), having high light transmittance so as to increase reflectivity, and providing an effect as if an image of the front surface of the material coexists on a background and a space behind.

To this end, the material is installed in a plane form inclined by 45° with respect to a floor screen, and a floor image is formed as a virtual image at a position symmetric based on a reflecting material according to a light reflection law, so that an audience may have the same effect as if the floor image exists on the stage when the audience views the image.

The technique provides an effect of floating objects (virtual images) in a space, thereby being called “floating hologram” as one scheme of a pseudo hologram. The technique has been already widely known, and is currently widely used in offline performances, musicals, and the like, so that a particular matter thereof will not be mentioned.

In the technique, transmission of background light and reflection of a floor image needs to be simultaneously performed, so that in order to obtain a clear hologram image, a projector of high ANSI lumen needs to be used in consideration of reflectivity, and light intensity of a reflected image is not high, so that interference of ambient light needs to be minimal. Accordingly, a theater has a limit in view that the theater is generally a dark room environment similar to a movie theater.

Currently, in a generally used floating hologram scheme, a transparent reflective film is placed at an angle of 45°, so that it is directed so that a floor image is reflected forward and is displayed so as to be seen together with a transmitted background object.

However, since the transmission of background light and the reflection of the floor image need to be simultaneously performed through one film, so that the amount of reflected light is small, there is a limitation in that the floating hologram needs to be used in a dark space so as to prevent interference of ambient light.

DISCLOSURE

Technical Problem

Accordingly, the technical object to be achieved by the present invention is to provide a refractive optical screen for forming one or more virtual images in a hologram space so as to provide a floating hologram effect as if two or more different images exist in one physical space by using a refraction property of light, and a floating hologram system using the same.

Technical Solution

An exemplary embodiment of the present invention provides a refractive optical screen which refracts incident light beams and adjusts a travelling direction of the light beams, the refractive optical screen including: a prism array in which a plurality of prisms for refracting one or more light beams toward a viewing direction of a viewer located at a front side of the refractive optical screen is arranged in a line, in which one or more virtual images formed by the one or more refracted light beams exist in one space to form a floating hologram.

In the prism array, the plurality of prisms, which refracts first light beams incident in a first direction toward the viewing direction and refracts second light beams incident in a second direction different from the first direction toward the viewing direction, may be continuously arranged in a line.

In the prism array, a plurality of micro trigonal prisms may be arranged in a vertical direction to the viewing direction in a line without having a gap.

In the prism array, a plurality of prisms for refracting first light beams incident in a first direction toward the viewing direction may be arranged in a line while being spaced apart from each other by a predetermined gap, and second light beams incident in a different direction from that of the first light beams may straightly pass through the gap.

In the prism array, a plurality of micro trigonal prisms may be regularly arranged in a vertical direction to the viewing direction while having the predetermined gap.

In the prism array, a plurality of micro trigonal prisms having different sizes and angles in consideration of a viewing angle of a viewer may be regularly arranged in a vertical direction to the viewing direction.

The prism array may include a plurality of trigonal prisms having different apex angles so as to have the same incident angle, and the same incident angle may be set by using an angle (ri) between a segment of a line connecting a visual field of the viewer and an apex of each prism and a reference horizontal surface, an upper apex angle (ai) of each prism, and a light beam passing ratio (a) between a first facet disposed at an upper portion of each prism and a second facet disposed in a lower end of the prism.

The prism array may include a plurality of micro trigonal prisms having a prism size according to a pitch size calculated by using Cycles Per Degree (CPD) based on a Human Visual System (HVS) that is a value representing a human retina limit.

The prism array may include a plurality of first prisms which refracts first light beams incident in a first direction toward the viewing direction, and a plurality of second prisms which refracts second light beams incident in a different direction from the first direction toward the viewing direction, and the plurality of first prisms and the plurality of second prisms may be arranged in a line while being spaced apart from each other by a predetermined gap, and third light beams incident in a different direction from those of the second light beams and the first light beams may straightly pass through the gap.

The plurality of first prisms may be a micro trigonal prism having the same angle and size, the plurality of second prisms may be a micro trigonal prism having a shape symmetric to a shape of the plurality of first prisms and having a predetermined angle and size, and in the prism array, the plurality of first prisms and the plurality of second prisms may be regularly arranged in a structure symmetric based on a center of the viewing direction in a vertical direction to the viewing direction while having the same gap.

Another exemplary embodiment of the present invention provides a floating hologram system, including: a projector 1 which outputs a first image; a projector 2 which outputs a second image; a reflective screen 1 which is located in a direction diagonal to the projector 1 and reflects the first image; a reflective screen 2 which is located in a direction diagonal to the projector 2 and reflects the second image; and a refractive optical screen which is disposed at a location facing a viewing direction of a viewer, and refracts a plurality of first light beams toward the viewing direction when the plurality of first light beams reflected from the reflective screen 1 is incident, and refracts a plurality of second light beams toward the viewing direction when the plurality of second light beams reflected from the reflective screen 2 is incident, in which the plurality of refracted first light beams forms a first virtual image in a hologram space, and the plurality of refracted second light beams forms a second virtual image in a hologram space.

The refractive optical screen may include a prism array in which a plurality of prisms including a first facet that is an optical plane refracting the first light beams toward the viewing direction and a second facet that is an optical plane refracting the second light beams incident in a different direction from a direction of the first light beams toward the viewing direction are continuously arranged in a vertical direction to the viewing direction in a line.

The projector 1 and the reflective screen 2 may be located in an upper portion of the hologram space, and the projector 2 and the reflective screen 1 may be located in a lower portion of the hologram space, and a floating hologram image, in which the second virtual image is a front image and the first virtual image is a rear image, may be output in the hologram space.

Image points of an image reflected from each of the reflective screen 1 and the reflective screen 2 may form virtual image points on an extension line having the same length with respect to a refractive surface of a prism, respectively, and positions and angles of the virtual image points may be changed according to an installation location and angle of each of the reflective screen 1 and the reflective screen 2.

Still another exemplary embodiment of the present invention provides a floating hologram system, including: a projector which outputs a first image; a reflective screen which is located in a direction diagonal to the projector and reflects the first image; a stage, on which an actual object is located; and a refractive optical screen, which is disposed at a location facing a viewing direction of a viewer, and refracts a plurality of first light beams toward the viewing direction when the plurality of first light beams reflected from the reflective screen is incident, and allows a plurality of second light beams generated by the real object to straightly pass through toward the viewing direction, in which the plurality of refracted first light beams forms a virtual image in a hologram space, and the first virtual image and a real object image using the second light beams are formed together in the hologram space.

In the refractive optical screen, a plurality of prisms refracting the first light beams may be regularly arranged in a vertical direction to the viewing direction while being spaced apart from each other by a predetermined gap, and the second light beams may straightly pass through the gap.

The projector 1 may be located in an upper portion of the hologram space, the stage and the reflective screen may be located in a lower portion of the hologram space, and in the hologram space, a floating hologram image, in which the first virtual image is a front image and the real object image is a rear image, may be generated.

Yet another exemplary embodiment of the present invention provides a floating hologram system, including: a projector 1 which outputs a first image; a projector 2 which outputs a second image; a reflective screen 1 which is located in a direction diagonal to the projector 1 and reflects the first image; a reflective screen 2 which is located in a direction diagonal to the projector 2 and reflects the second image; a stage, on which an actual object is located; and a refractive optical screen, which is disposed at a location facing a viewing direction of a viewer, and refracts a plurality of first light beams toward the viewing direction when the plurality of first light beams reflected from the reflective screen 1 is incident, refracts a plurality of second light beams toward the viewing direction when the plurality of second light beams reflected from the reflective screen 2 is incident, and allows a plurality of third light beams generated by the real object to straightly pass through toward the viewing direction, in which the plurality of refracted first light beams forms a first virtual image in a hologram space, the plurality of refracted second light beams forms a second virtual image in the hologram space, and the first virtual image, the second virtual image, and the real object image using the third light beams are formed together in the hologram space.

The refractive optical screen may include a plurality of first prisms which refracts the first light beams incident in a first direction toward the viewing direction, and a plurality of second prisms which refracts the second light beams incident in a second direction different from the first direction toward the viewing direction, and the plurality of first prisms and the plurality of second prisms may be arranged in a vertical direction to the viewing direction in a line in a symmetric structure while being spaced apart from each other by a predetermined gap, and the third light beams incident in a different direction from the directions of the first light beams and the second light beams may straightly pass through the gap.

The projector 1 and the reflective screen 2 may be located in an upper portion of the hologram space, the projector 2 and the reflective screen 1 may be located in a lower portion of the hologram space, and the stage may be located behind the projector 1 and the projector 2, and in the hologram space, a floating hologram image, in which the first virtual image is an upper front image, the second virtual image is a lower front image, and the real object image is a rear image, may be formed.

Advantageous Effects

According to the exemplary embodiments of the present invention, unlike the use of only a light reflection property in the related art, images of two different real objects or displays are refracted through the refractive optical screen to allow light to travel, so that the images are displayed as if a plurality of virtual images exists in one space, thereby providing a floating hologram effect as if a real person appears in front of the eye.

In addition, the small refractive optical screen formed of the micro prism array is utilized, and it is possible to express virtual images as if two images exist together in one space by refracting travelling light of two different images existing in a space.

In addition, it is possible to provide a floating hologram effect by applying a method of dividing images into a front image and a rear image.

