KR20210004833A - Fourier-Beam Shaper and Display Apparatus including thereof - Google Patents

Abstract

Provided are a Fourier beam converter and a display device including the same. The disclosed Fourier beam converter comprises: a waveguide; an input coupler which sequentially advances a plurality of lights into the waveguide according to the time; and a spatial conversion unit which outputs the plurality of lights advancing through the waveguide in spatially different regions. A miniaturized display device can be implemented using the Fourier beam converter.

Description

Fourier beam converter and display device including the same TECHNICAL FIELD

The present disclosure relates to a Fourier beam converter and a display device including the same.

Recently, as electronic devices and display devices capable of implementing virtual reality (VR) have been developed, interest in this has increased. A technology (plan) capable of realizing augmented reality (AR) and mixed reality (MR) as the next stage of virtual reality (VR) is also being studied.

Augmented reality (AR) is a display technology that further increases the effect of reality by superimposing (combining) virtual objects or information on the environment of the real world, unlike virtual reality (VR) that presupposes a complete virtual world. to be. While virtual reality (VR) can be limitedly applied to fields such as games and virtual experiences, augmented reality (AR) has an advantage that it can be applied to various reality environments. In particular, augmented reality (AR) is drawing attention as a next-generation display technology suitable for a ubiquitous environment or an Internet of things (IoT) environment. Such augmented reality (AR) can be said to be an example of mixed reality (MR) in that the real world and additional information (virtual world) are mixed and displayed.

Such an image system projects the generated image to the user's eyes using an optical system. In general, an optical system uses a lens. In order to project an image to the user's eye, the imaging system basically needs a spatial light modulator and a distance to the lens and a distance to the lens and the user's eye. This has a problem of increasing the volume of the image system.

An exemplary embodiment provides a Fourier beam converter and a display device including the same.

A Fourier beam converter according to an embodiment includes: a waveguide; An input coupler for propagating a plurality of lights into the waveguide; And a spatial conversion unit configured to output the plurality of lights traveling through the waveguide in spatially different regions.

In addition, the spatial conversion unit may direct and output each of the plurality of lights in a specific direction.

In addition, the spatial conversion unit may output at least two of the plurality of lights by directing them in different directions.

In addition, the spatial conversion unit is arranged in a direction transverse to the output direction of the plurality of lights, each of the plurality of selective transmission that transmits any one of the plurality of light to the outside and does not transmit the remaining light to the outside. It may include an element.

In addition, each of the plurality of selective transmitting elements may selectively transmit light according to optical characteristics.

In addition, the optical characteristics may include diffraction characteristics.

In addition, at least two of the plurality of selective transmission elements may have at least one of a grating structure and a material different from each other.

In addition, each of the plurality of selective transmitting elements may selectively transmit or may not transmit light according to an applied electrical signal.

In addition, the plurality of lights may be incident on the input coupler at different angles of incidence.

In addition, the spatial conversion unit may output the plurality of lights in spatially different regions based on the incident angle.

In addition, the spatial conversion unit may image each of the plurality of lights on different positions in the external space.

In addition, the external space may be a space within the pupil of the user.

In addition, each of the plurality of lights may be a partial image of the frame image.

In addition, each of the plurality of lights may be a pixel image of the frame image.

In addition, a size of light output from the spatial conversion unit may be different from a size of a corresponding light incident on the input coupler.

In addition, a size of light output from the spatial conversion unit may be larger than a size of corresponding light incident on the input coupler.

In addition, the input coupler may include: a first input coupler configured to propagate first rays of the plurality of lights into the waveguide; And a second input coupler configured to propagate second lights of the plurality of lights into the waveguide.

In addition, the first lights and the second lights may be synchronized to each be incident on the first input coupler and the second input coupler at the same time period.

In addition, the waveguide may include a first waveguide through which the first lights travel; And a second waveguide through which the second lights travel.

The spatial conversion unit may include: a first spatial conversion unit disposed on the first waveguide and outputting the first light from different regions to form a first sub-frame image on the external space; And a first spatial conversion unit disposed on the second waveguide and outputting the second light from different regions to form a second sub-frame image on the external space.

Also, the first and second sub-frame images may be imaged on different regions of the external space.

In addition, the first and second sub-frame images may be different partial images of the same frame image.

Meanwhile, a display device according to an exemplary embodiment includes the Fourier beam converter described above; And a light source that emits the plurality of lights to the Fourier beam converter.

In addition, it may further include an expander (Eye Pupil expander) for expanding the plurality of light output from the spatial conversion unit.

In addition, the expander may transmit light corresponding to a reality environment.

It may further include a spatial light modulator for adding image information to the Fourier beam converter or a plurality of lights emitted from the light source.

And, it may further include a; direction adjustment member for adjusting the incident angle of the plurality of light incident on the Fourier beam converter.

A miniaturized display device can be implemented using a Fourier beam converter.

1 is a schematic diagram of a display device including a Fourier beam converter according to an exemplary embodiment.
FIG. 2 is a diagram illustrating the structure of the Fourier beam converter of FIG. 1.
3 is a diagram illustrating an example of a selective transmission element included in a spatial conversion unit according to an exemplary embodiment.
4 is a diagram illustrating a part of a Fourier beam converter including a selective transmission element according to another embodiment.
5 is a diagram illustrating a method of selectively outputting a plurality of light from a plurality of selectively transmitting elements according to an exemplary embodiment.
6 is a diagram illustrating a display device 10a according to another exemplary embodiment.
7 is a diagram illustrating a display device according to another exemplary embodiment.
8 is a diagram illustrating a display device according to another exemplary embodiment.
9 is a diagram illustrating a part of a display device according to another exemplary embodiment.
10 is a diagram illustrating a display device including a Fourier beam converter according to another exemplary embodiment.
11 is a schematic diagram of a display device for adding an image to Fourier transformed light according to another exemplary embodiment.
12 is a diagram illustrating a Fourier beam converter including a spatial light modulator according to an embodiment.
13 is a block diagram illustrating a display device according to another exemplary embodiment.
14 is a diagram illustrating an electronic device to which a display device according to an exemplary embodiment is applied.
15 is a diagram illustrating an electronic device to which a display device according to another exemplary embodiment is applied.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following drawings, the same reference numerals refer to the same elements, and the size of each element in the drawings may be exaggerated for clarity and convenience of description. Meanwhile, the embodiments described below are merely exemplary, and various modifications are possible from these embodiments.

Hereinafter, what is described as "top" or "top" may include not only those directly above by contact, but also those above non-contact.

Singular expressions include plural expressions unless the context clearly indicates otherwise. In addition, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

The use of the term "above" and similar reference terms may correspond to both the singular and the plural.

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

1 is a diagram schematically illustrating a display device including a Fourier beam converter according to an exemplary embodiment, and FIG. 2 is a diagram illustrating a structure of the Fourier beam converter of FIG. 1. Referring to FIG. 1, the display device 10 includes a beam output unit 100 that outputs a plurality of lights, and a Fourier beam converter 200 that outputs each of a plurality of lights received from the beam output unit 100 in spatially different regions. ) And a processor 300 that controls the beam output unit 100 and/or the Fourier beam converter 200 to display an image.

The beam output unit 100 may sequentially output a plurality of lights according to time. Here, the light may be light corresponding to a partial image of the frame image. For example, the light may be light corresponding to a pixel image of a frame image or light corresponding to the sum of a plurality of pixel images included in the frame image. The light may be light in which different frequencies are mixed. For example, the light may be a mixture of red light, green light, and blue light.

The beam output unit 100 may include a light source 110 and a spatial light modulator 130. The light source 110 may provide coherent light. The light source 110 may include a laser diode. However, if it has a certain degree of spatial coherence, it can be diffracted and modulated by the spatial light modulator 130 to have coherence. Therefore, if light having a certain degree of spatial coherence is output, another light source Can also be used.

The light source 110 may include a plurality of light sources that output light of different wavelengths. For example, a first light source that outputs light of a first wavelength band, a second light source that outputs light of a second wavelength band different from the first wavelength, and outputs light of a third wavelength different from the first and second wavelengths It may include a third light source. Light of the first, second, and third wavelengths may be red, green, and blue light, respectively.

The spatial light modulator 130 modulates the light output from the light source 110 under the control of the processor 300 to output light including image information. The resolution of the modulated light may be determined by the spatial resolution of the spatial light modulator 130. For example, when the spatial light modulator 130 is composed of one pixel, the modulated light may be light corresponding to a pixel image. Alternatively, if the spatial resolution of the spatial light modulator 130 is 2*2, the resolution of the modulated light may also be 2*2. The spatial light modulator 130 may output a 2D image or light corresponding to a 3D image or a holographic image having different depth information.

The spatial light modulator 130 may be an amplitude modulated spatial light modulator, a phase modulated spatial light modulator, or a complex spatial light modulator that modulates both amplitude and phase. In addition, the spatial light modulator may be a transmissive light modulator or a reflective light modulator, or a transflective light modulator. As a specific example, the spatial light modulator 130 includes a liquid crystal on silicon (LCoS) panel, a liquid crystal display (LCD) panel, a digital light projection (DLP) panel, an organic light emitting diode (OLED) panel, and a micro-light emitting diode (M-OLED) panel. organic light emitting diode), and the like. Here, the DLP panel may include a digital micromirror device (DMD).

The beam output unit 100 may further include a direction adjusting member 150 that adjusts a traveling direction of light so that the light output from the spatial light modulator 130 is incident on the Fourier beam converter 200 at a specific angle. The direction adjustment member 150 may be an actuator capable of adjusting the position of the spatial light modulator 130 to adjust the propagation direction of light, or may be an optical element that directly adjusts the propagation direction of light output from the spatial light modulator 130 have. The optical element may be an active optical element capable of differently adjusting a traveling direction of light under the control of the processor 300.

The direction adjustment member 150 may adjust the propagation direction of light so that a plurality of lights proceed in different directions until a plurality of lights corresponding to one frame image are output. For example, when the resolution of the light is 2*2 and the resolution of the frame image is 20*20, the direction adjustment member 150 may control 100 lights to travel in 100 different directions.

The processor 300 may control the beam output unit 100 to output light. The light output period may be determined based on a resolution of a frame image to be imaged, a resolution of light modulated by the spatial light modulator 130 and a frame time. For example, if the frame time is 1/60 second and the optical resolution in the spatial light modulator 130 is 1/10 of the resolution of the frame image, the processor 300 performs optical data at a period of 1/(60*10) seconds. The beam output unit 100 may be controlled so that this can be output.

In FIG. 1, the spatial light modulator 130 modulates light to output light including image information, but is not limited thereto. The light source 110 itself may output light including image information by the processor 300. In this case, the spatial light modulator 130 is not required, and the direction control member 150 may be an actuator that controls the position of the light source 110 or an optical element that controls the path of light output from the light source 110. have.

The Fourier beam converter 200 may image a frame image in an external space by outputting a plurality of lights received from the beam output unit 100 in spatially different regions. Referring to FIG. 2, the Fourier beam converter 200 spatially transmits a waveguide 210, an input coupler 220 for propagating a plurality of lights into the waveguide 210, and a plurality of lights traveling through the waveguide 210. It may include a spatial conversion unit 230 capable of outputting from different regions.

The waveguide 210 may be formed of a transparent member, for example, glass or a transparent plastic material, and may change the size of incident light while traveling inside the waveguide 210 by total reflection of the incident light. Thus, the size of light output from the spatial conversion unit 230 may be different from the size of light incident on the input coupler 220. The light output from the beam output unit 100 may be light in the form of a point, but since the light in the form of a point repeats total reflection in the waveguide 210, the size of the light traveling through the waveguide 210 increases, so that the light in the form of a plane is increased. Can be. In addition, light may be uniformly distributed while traveling through the waveguide 210. Thus, the size of the light output from the spatial conversion unit 230 may be larger than the size of the light incident on the input coupler 220.

The input coupler 220 may be disposed on a region of the waveguide 210. The input coupler 220 is shown to be disposed at the edge of the upper surface of the waveguide 210, but is not limited thereto. The input coupler 220 may be disposed under the waveguide 210. The input coupler 220 may include a diffractive member that diffracts and transmits the incident light. For example, the input coupler 220 may include a grating structure. The input coupler 220 may have a diffraction characteristic of diffracting and transmitting light irrespective of an incident angle of incident light.

The spatial conversion unit 230 may include a plurality of selective transmissive elements ST so that a plurality of light traveling in the waveguide 210 may be output in spatially different regions. The plurality of selective transmission elements ST may be arranged in two dimensions on the waveguide 210. The plurality of selective transmission elements ST may be arranged continuously or discontinuously.

Each of the selective transmission elements ST may transmit any one of a plurality of lights to the outside and block transmission of the remaining light to the outside. Each of the selective transmitting elements ST may or may not selectively transmit light according to optical characteristics. For example, each of the selective transmission elements ST may selectively transmit or may not transmit light according to diffraction characteristics. Alternatively, the optical properties of each of the selective transmitting elements ST may be changed by an electrical signal, so that light may or may not be selectively transmitted.

Each of the plurality of selective transmission elements ST may direct light in a specific direction and output it. For example, at least two of the plurality of selective transmission elements ST may direct transmitted light in different directions and output them. The degree of directivity described above may be determined by optical characteristics, for example, diffraction characteristics, of the selective transmission element ST, and may be determined by changing optical characteristics by an electrical signal.

The time required for the spatial converter 230 to output all of the plurality of lights constituting the frame image may be the same as the period in which the frame image is output, that is, the frame time. For example, the beam output unit 100 may output n lights corresponding to one frame image at 1/n intervals of the frame time. Each of the plurality of selective transmission devices ST may direct and output any one of n lights. As all n lights are output, the user can recognize the frame image. Since n lights are formed on different areas in an external space, for example, the user's pupil E, the user can recognize it as one image.

If a frame image of the same phase is incident on the waveguide, the waveguide and the beam output period must be separated by a certain distance or more. However, since the Fourier beam converter 200 independently receives and outputs light, there is no limit on the distance between the beam output unit 100 and the Fourier beam converter 200. This has the advantage of reducing the distance between the beam output unit 100 and the Fourier beam converter 200. In addition, since the Fourier beam converter 200 outputs a plurality of lights in spatially different areas to form a frame image, the display apparatus 10 can reproduce the frame image only by the beam output unit 100 outputting the light. have. Thus, the light source 110 and the spatial light modulator 130 included in the beam output unit 100 can be miniaturized. In addition, since each of the selective transmission elements ST of the Fourier beam converter 200 directs light with a specific directional characteristic, a separate optical element, for example, a lens, or the like is not required. Thus, the configuration of the display device 10 can be simplified.

3 is a diagram illustrating an example of a selective transmission element included in a spatial conversion unit according to an exemplary embodiment. As shown in FIG. 3, the selective transmission elements ST may include a diffractive member having a grating structure. Each of the selective transmission elements ST may have different shapes, pitches (p), heights (h), directions (d), and materials of the grating (G). Thus, the diffraction efficiency of each selective transmission element ST may vary according to the incident angle of light. In FIG. 3, a plurality of selective transmissive elements ST having different directions of the gratings G are illustrated, but are not limited thereto.

For example, each of the selective transmission elements ST may be formed such that diffraction efficiency for light incident at a specific incident angle is equal to or greater than a first reference value, and diffraction efficiency for the remaining incident angles is less than a second reference value. Here, the second reference value may be less than or equal to the first reference value. Thus, each of the selective transmission elements ST of the spatial conversion unit 230 diffracts and transmits light incident at a specific incidence angle, while light incident at an incidence angle different from the specific incidence angle can be totally reflected into the waveguide 210. have. The plurality of selective transmission elements ST may selectively diffract and transmit a plurality of light, and the spatial conversion unit 230 may output light in different regions.

The selective transmission element ST for transmitting light may direct light in a specific direction and output it. The degree of directivity may be determined by an incident angle of incident light, a diffraction characteristic of the selectively transmitting element ST, for example, a grating structure and a material of the selectively transmitting element ST.

It has been said that the diffraction characteristics of the selective transmission element ST vary depending on the shape, pitch (p), height (h), direction (d), material, etc. of the grating (G) included in the selective transmission element (ST), but is not limited thereto. Does not. The selective transmission element ST may be a device whose diffraction characteristic varies according to an applied electrical signal.

4 is a diagram illustrating a part of a Fourier beam converter including a selective transmission element according to another embodiment. As shown in FIG. 4, the spatial conversion unit 230 of the Fourier beam converter includes an output coupler 231 disposed on the waveguide 210 and a plurality of selective transmission elements ST disposed on the output coupler 231. It may include. The output coupler 231 may include a grating structure that diffracts and transmits light.

The selective transmission device ST may be a device whose transmittance is changed according to an applied electrical signal. Each of the selective transmission elements (ST) is dispersed in the base layer 232 and the base layer 232, and the optical properties are changed according to the applied electrical signal to adjust the transmittance of a plurality of electro-optical particles 233 and a plurality of It may include an electrode unit 234 for applying an electrical signal to the electro-optical particles 233.

The base layer 232 may be formed of a transparent polymer material. For example, the base layer 232 may be a transparent cured resin.

The electro-optic particles 233 are materials having an electro-optic effect. The electro-optical effect is a phenomenon in which optical properties change according to an electric field, and the electro-optical particles 233 may change refractive index, phase retardation, polarization characteristics, etc. of a material according to the presence of the electric field and/or the strength of the electric field.

The electro-optical particles 233 may include liquid crystal. In the liquid crystal, at least one of refractive index and polarization characteristics may change according to the presence or absence of an electric field and/or the strength of the electric field. For example, Polymer Dispersed Liquid Crystal (PDLC), Polymer Network Liquid Crystal (PNLC), Cholesteric Liquid Crystal, Smectic Liquid Crystal, etc. It can be used as the optical particle 233.

When an electric field is applied to the base layer 232, the electro-optical particles 233 equally refract incident light, so that the electro-optical particles 233 may become transparent. Thus, the electro-optical particles 233 may transmit incident light. That is, when an electric signal is applied, the selective transmission element ST enters a transmission mode for transmitting light.

On the other hand, if the electric field is not applied to the base layer 232, the electro-optical particles 233 refract incident light in different directions with different refractive indices depending on the location, so that the electro-optical particles 233 may become opaque. Thus, the electro-optical particles 233 may scatter incident light so that the light cannot be transmitted. That is, when an electrical signal is not applied, the selective transmitting element ST enters a non-transmissive mode in which light is not transmitted.

As another example, when an electric field is applied to the electro-optical particles 233, the electro-optical particles 233 refract light in different directions with different refractive indices depending on the position to enter a non-transmissive mode, and the electric field is applied to the electro-optical particles 233. If not applied, the electro-optical particles 233 may equally refract light to enter a transmission mode.

Thus, depending on the applied electrical signal, one of the selective transmission elements ST is in a transmission mode to output the light diffracted by the output coupler 231 to the outside, and the other is in a non-transmissive mode and is in the output coupler ST. The diffracted light may not be output to the outside. The electrical signal may be synchronized with light output from the beam output unit 100, and the selective transmission element ST may selectively transmit light, and the spatial conversion unit 230 transmits light in spatially different areas. Can be printed.

5 is a diagram illustrating a method of selectively outputting a plurality of light from a plurality of selectively transmitting elements according to an exemplary embodiment. As shown in FIG. 5, light may be incident on the input coupler 220 at a specific incident angle. The input coupler 220 diffracts and transmits the light to proceed to the waveguide 210. Light traveling through the waveguide 210 may be transmitted through the selective transmitting element ST that satisfies a specific condition among the plurality of selective transmitting elements ST and emitted to the outside, and may not be transmitted through the other selective transmitting elements ST. .

For example, when the plurality of selective transmission elements ST are composed of diffractive members having different diffraction characteristics, the selective transmission element ST having low diffraction efficiency with respect to an incidence angle totally reflects the incident light into the waveguide 210, The selective transmission element ST having a high diffraction efficiency with respect to an incident angle may diffract and transmit incident light. Thus, light may be output to the outside only in a specific selective transmission element ST. For example, the light L1 incident at the first incident angle θ1 is diffracted and transmitted by the first selective transmission element ST1 having high diffraction efficiency, while the remaining selective transmission element ST is totally reflected and thus the waveguide 210 ) To proceed. In addition, the light L2 incident at the second incident angle θ2 diffracts and transmits the second selective transmission element ST2 having high diffraction efficiency, while the remaining selective transmission element ST is totally reflected to form the waveguide 210. Proceed.

Alternatively, when the plurality of selective transmitting elements ST includes electro-optical particles 233 whose optical properties change according to the applied electrical signal, the selective transmitting element ST in a transmission mode state in response to the electrical signal is incident The selective transmission mode that transmits light and is in a non-transmissive mode in response to an electrical signal may not transmit incident light. Thus, the light may be output to the outside only in the selective transmission element ST in the transmission mode state.

For example, the light L1 incident at the first incident angle θ1 is transmitted through the first selective transmitting element ST1, which is a transmissive mode, while the remaining selective transmissive element ST, which is a non-transmissive mode, is scattered or totally reflected to the waveguide. You can proceed to (210). In addition, the light L2 incident at the second incident angle θ2 transmits through the second selectively transmitting element ST2, which is a transmissive mode, while the remaining selective transmissive element ST, which is in the non-transmissive mode, is scattered or totally reflected to the waveguide 210. ) To proceed.

6 is a diagram illustrating a display device according to another exemplary embodiment. Comparing FIGS. 1 and 6, the display device 10a of FIG. 6 may further include an exit pupil expander 150. The expander 400 may expand the light output from the Fourier beam converter 200 in one direction, for example, an x-axis. The expander 400 is not shown but may include a waveguide, an input coupler, and an output coupler. The input coupler and the output coupler of the expander 400 may also be formed of a diffractive member. However, the input coupler and the output coupler of the expander 400 may have a diffraction characteristic of diffracting and transmitting light irrespective of an incident angle.

In addition, since the expander 400 may be formed of a transparent material, light corresponding to a reality environment (R), for example, light reflected in a real environment or light generated in a real environment is transmitted to the user. It may be formed in the pupil (E) of. Thus, the user can simultaneously recognize the frame image formed by the Fourier beam converter 200 and the real environment. However, it is not limited thereto. The expander 400 may image only the light output from the Fourier beam converter 200 in the pupil E of the user.

One beam output unit 100 and one Fourier beam converter 200 need as much light as the number of selective transmission elements ST in order to image one frame image. And, as the number of lights increases, the light output period should be shortened. This may cause a load on signal processing of the processor 300.

The display apparatus according to an embodiment may image a frame image using a plurality of beam outputs and a plurality of Fourier beam converters.

7 is a diagram illustrating a display device according to another exemplary embodiment. The display apparatus 10b illustrated in FIG. 7 may include a plurality of beam output units 101 and a plurality of Fourier beam converters 201. Each of the beam output units 101 may output a plurality of lights to each corresponding Fourier beam converter 201, and one frame image may be imaged by a plurality of lights output from the plurality of Fourier beam converters 201. I can.

Each of the plurality of beam output units 101 may include a light source, a spatial light modulator, and a direction adjustment member. Each of the beam output units 101 has been described in FIG. 1, and a detailed description thereof will be omitted.

Each of the plurality of Fourier beam converters 201 may also include a waveguide 211, an input coupler 221, and a spatial conversion unit 231. The input coupler 221 is disposed on one region of the waveguide 211 and may be a diffractive member that diffracts and transmits incident light. For example, the input coupler 221 may include a grating structure, and may have a diffraction characteristic of diffracting and transmitting light regardless of an incident angle of incident light.

The spatial conversion unit 231 may include a plurality of selective transmissive elements ST so that a plurality of advancing lights may be output in spatially different regions. The plurality of selective transmission elements ST may be arranged in one dimension on the waveguide 211. However, it is not limited thereto. The plurality of selective transmission elements ST may be arranged in two dimensions.

The plurality of selective transmission elements ST may transmit only light that satisfies a specific condition due to different optical characteristics and may not transmit the remaining light. The optical characteristics may be fixed during the manufacturing process of the selective transmission element ST, or may be changed according to an applied electrical signal.

For example, each of the plurality of selective transmission elements ST may have different diffraction characteristics. Each of the selective transmission elements ST may diffract and transmit light incident at a specific incident angle, while light incident at an incident angle different from the specific incident angle may be totally reflected into the waveguide 211. The plurality of selective transmission elements ST may selectively diffract and transmit a plurality of light, and the spatial conversion unit 231 may output light in different regions.

Alternatively, the plurality of selective transmission elements ST may include electro-optical particles 233 whose optical properties are changed according to an applied electrical signal. Each of the selective transmitting elements ST transmits light incident to the selective transmitting element ST in the transmissive mode, while the light incident to the selective transmissive element ST in the non-transmissive mode can be scattered or totally reflected into the waveguide 211. have.

In addition, each selective transmission device ST may direct light in a specific direction while transmitting light. Thus, a plurality of lights output from the plurality of spatial conversion units 231 may be imaged as a frame image in an external space. The external space may be a space within the user's pupil E.

Each of the beam output units 101 may output a plurality of lights to a corresponding respective Fourier beam converter 201. The plurality of beam output units 101 may be synchronized to output a plurality of lights in the same time period, and the plurality of Fourier beam converters 201 may also output a plurality of lights in the same time period so that one frame image may be imaged. For example, each Fourier beam converter 201 can image a line frame image by outputting light from a different area, and only one frame image is formed by each of the plurality of Fourier beam converters 201 forming a line frame image. This may result in image formation.

Each beam output unit 101 outputs as much light as the selective transmission element ST of the corresponding Fourier beam converter 201, while a single frame image by a plurality of lights output from the plurality of Fourier beam converters 201 Since this image can be formed, the light output period can be lengthened. This can reduce the load on the processor 300.

8 is a diagram illustrating a display device according to another exemplary embodiment. The display apparatus 10c of FIG. 8 includes first and second beam outputs 102 and 103 respectively outputting a plurality of lights, and first and second Fourier beam converters respectively forming a half frame image using a plurality of lights. (202, 203) may be included. Since one frame image is formed by each of the first and second Fourier beam converters 202 and 203 forming half-frame images, the output of light rather than forming a frame image using one light source and one Fourier beam converter You can lengthen the cycle.

In FIGS. 7 and 8, it is assumed that each Fourier beam converter 201, 202, 203 forms a partial image of a frame image, such as a line frame image or a half frame image, but is not limited thereto. Combinations of a Fourier beam converter and a beam output unit may vary to image a partial image. For example, one frame image may be imaged by imaging a quarter frame image with 4 beam outputs and 4 Fourier beam converters.

The display device 10c of FIG. 8 may further include an expander 400. The expander 400 may expand the light output from the first Fourier beam converter 202 and the light output from the second Fourier beam converter 203.

9 is a diagram illustrating a part of a display device according to another exemplary embodiment. The first waveguide 212 of the first Fourier beam converter 202a and the second waveguide 213 of the second Fourier beam converter 203a shown in FIG. 9 are lengths of the first and second waveguides 212 and 213 At least some regions overlap in a direction perpendicular to the direction, for example, in the Y-axis direction. As the lengths of the first and second waveguides 212 and 213 become longer, the uniformity of light traveling through the first and second waveguides 212 and 213 may be increased.

10 is a diagram illustrating a display device including a Fourier beam converter according to another exemplary embodiment. As shown in FIG. 10, the beam output unit 100b may include a light source 110b, a waveguide 160, and a spatial light modulator 130b. The beam output unit 100b may output light corresponding to the frame image using the waveguide 160 and the spatial light modulator 130b. The Fourier beam converter 200b may include a plurality of selective transmission elements ST. Each of the plurality of selective transmission elements ST may have different directivity characteristics according to an area where they are located, and may direct incident light differently. Even if the frame image is output from the beam output unit 100b, each selective transmission element ST of the Fourier beam converter 200b may transmit light while directing light in a specific direction according to optical characteristics. Thus, a frame image can be imaged on an external space.

Until now, it has been said that light including image information is incident on the Fourier beam converter, but the present invention is not limited thereto. Image information may be added to light output from the Fourier beam converter, and the Fourier beam converter may include a spatial light modulator to add image information.

11 is a schematic diagram of a display device for adding an image to Fourier transformed light according to another exemplary embodiment. 11, the Fourier beam converter 200 may emit a plurality of lights received from the light source 110 as spatially separated light, that is, Fourier transformed light. The Fourier beam converter 200 may include a waveguide, an input coupler for propagating a plurality of lights into the waveguide, and a spatial transform unit capable of outputting a plurality of lights traveling through the waveguide in different regions. In addition, the spatial conversion unit may include a plurality of selective transmitting elements so that a plurality of light traveling in the waveguide can be output in spatially different areas, and the plurality of selective transmitting elements may be arranged in two dimensions on the waveguide. . The plurality of selective transmission elements may be arranged in succession or may be arranged discontinuously.

Each of the selective transmitting elements may transmit any one of a plurality of lights to the outside according to optical characteristics and block transmission of the remaining light to the outside. The selective transmission element may include a plurality of diffractive members having different diffraction characteristics, or may include a plurality of optical particles whose optical characteristics are changed according to an electrical signal. The structure of the Fourier beam converter has been described above, and a detailed description thereof will be omitted.

The light emitted from the light source 110 may not include image information, and the Fourier beam converter 200 may output light without image information to different spaces. In addition, the spatial light modulator 130c may add image information to the light emitted from the Fourier beam converter 200. Since the light output from the Fourier beam converter 200 is temporally and spatially separated light, the spatial light modulator 130c may add image information to the spatiotemporally separated incident light. Since the lights output from the spatial light modulator 130c are spatiotemporally separated sub-images, the display device of FIG. 11 may provide a frame image by imaging each of the sub-images.

12 is a diagram illustrating a Fourier beam converter including a spatial light modulator according to an embodiment. As shown in FIG. 12, the Fourier beam converter 200a is a spatial light modulator 130d disposed between the waveguide 210a and the spatial transforming unit 230a, which are spaced apart, and the waveguide 210a and the spatial transforming unit 230a. ) Can be included. On the waveguide 210a, an input coupler 211 to which light is incident from a light source (not shown), and an output coupler 231a for outputting light proceeding from the waveguide 210a to the spatial light modulator 130d may be disposed.

The light output from the waveguide 210a may be modulated by the spatial light modulator 130d to be light including image information. Light and image light including image information are incident on the spatial conversion unit 230a. The selective transmission element ST included in the spatial conversion unit 230a may transmit specific light and block transmission of the remaining light according to optical characteristics. The optical characteristics of the selective transmission element may be varied or fixed according to the applied electrical signal. The optical characteristics may be diffraction characteristics, scattering characteristics, reflection characteristics, refractive characteristics, and the like.

The display device according to an embodiment may be implemented as a single hardware device or a combination of a plurality of hardware devices. For example, the display device may include a slave including a light source unit and an optical scanner, and a master including a processor.

13 is a block diagram illustrating a display device according to another exemplary embodiment. Referring to FIG. 13, a display apparatus 10g includes a beam output unit 100, a Fourier beam converter 200, and a slave S including a first communication unit 510, a second communication unit 520 and a processor 300. It may include a master (M) comprising a. Since the beam output unit 100 and the Fourier beam converter 200 have been described above, detailed descriptions will be omitted. The slave S may be implemented as a wearable device, for example, the head mounted display device 100, and the master M may be a mobile phone or a computer as an electronic device separate from the wearable device.

The first and second communication units 510 and 520 may provide a control command of the processor 300 to the beam output unit 100 and the Fourier beam converter 200. The first and second communication units 510 and 520 may include a short-range wireless communication unit and a mobile communication unit.

The method of controlling the beam output unit 100 and the Fourier beam converter 200 of the processor 300 may be implemented as a S/W program including instructions stored in a computer-readable storage media. have. The computer, as an apparatus capable of calling a stored instruction from a storage medium and operating according to the disclosed embodiments according to the called instruction, may include a display apparatus according to the disclosed embodiments.

Although not shown in FIGS. 11 to 13, an expander for expanding light corresponding to an image in one direction may be disposed.

The display devices 10, 10a, 10b, 10c, 10d, 10e, 10f, and 10g described so far and the Fourier beam converters 200 and 200a may be a component of the wearable device. For example, the display device may be applied to a head mounted display (HMD). In addition, the display device may be applied to a glasses-type display or a goggle-type display. Wearable electronic devices may be operated in conjunction with (or connected to) a smart phone. 14 and 15 are diagrams illustrating various electronic devices to which a display device according to exemplary embodiments can be applied.

The above-described Fourier beam converter and the display device including the same have been described with reference to the embodiments shown in the drawings, but this is only exemplary, and various modifications and other equivalent embodiments are possible from those of ordinary skill in the art. You will understand that Therefore, the disclosed embodiments should be considered from an illustrative point of view rather than a limiting point of view. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

10, 10a, 10b, 10c, 10d, 10e, 10f: display device
100, 101, 102, 103: beam output
110: light source
120: spatial light modulator
200, 201, 202, 202a, 203, 203a: Fourier beam transducer
210, 211, 213: waveguide
220: input coupler
230: space transform unit
300: processor
ST: optional transmissive element

Claims (27)

Waveguide;
An input coupler for propagating a plurality of lights into the waveguide; And
Fourier beam converter comprising a; spatial transform unit for outputting the plurality of light traveling the waveguide in spatially different regions. The method of claim 1,
The spatial conversion unit,
Fourier beam converter for directing and outputting each of the plurality of lights in a specific direction. The method of claim 1,
The spatial conversion unit,
Fourier beam converter for outputting at least two of the plurality of lights by directing them in different directions. The method of claim 1,
The spatial conversion unit,
Fourier beam converter comprising a plurality of selective transmission elements arranged in a direction transverse to the output direction of the plurality of lights, each of which transmits any one of the plurality of lights to the outside and does not transmit the remaining light to the outside . The method of claim 4,
Each of the plurality of selective transmission elements,
Fourier beam transducer that selectively transmits light according to optical properties. The method of claim 5,
The optical properties,
Fourier beam transducer including diffraction properties. The method of claim 5,
At least two of the plurality of selective transmission elements,
Fourier beam transducers in which at least one of the grating structures and materials are different from each other. The method of claim 5,
Each of the plurality of selective transmission elements,
Fourier beam converter that selectively transmits or does not transmit light according to an applied electrical signal. The method of claim 1,
A Fourier beam converter in which the plurality of lights are incident on the input coupler at different angles of incidence. The method of claim 9,
The spatial conversion unit,
Fourier beam converters for outputting the plurality of lights in spatially different regions based on the incident angle. The method of claim 1,
The spatial conversion unit,
Fourier beam converter for forming each of the plurality of lights onto different positions in an external space. The method of claim 11,
The outer space,
Fourier beam transducer, the space in the user's pupil. The method of claim 1,
Each of the plurality of lights
Fourier beam converter that is a partial image of the frame image. The method of claim 13,
Each of the plurality of lights
Fourier beam converter that is a pixel image of the frame image. The method of claim 1,
The size of light output from the spatial conversion unit is
Fourier beam converters having different magnitudes of corresponding light incident on the input coupler. The method of claim 15,
The size of light output from the spatial conversion unit is
A Fourier beam converter that is larger than a size of a corresponding light incident on the input coupler. The method of claim 1,
The input coupler,
A first input coupler configured to propagate first rays of the plurality of lights into the waveguide; And
Fourier beam converter comprising a; a second input coupler for advancing second light of the plurality of light to the inside of the waveguide. The method of claim 17,
A Fourier beam converter in which the first light and the second light are synchronized and incident on the first input coupler and the second input coupler, respectively, at the same time period. The method of claim 17,
The waveguide,
A first waveguide through which the first lights travel; And
Fourier beam converter comprising a; a second waveguide through which the second light travels. The method of claim 19,
The spatial conversion unit,
A first spatial conversion unit disposed on the first waveguide and configured to form a first sub-frame image on the external space by outputting the first lights in different regions; And
And a first spatial transform unit disposed on the second waveguide and outputting the second light from different regions to form a second sub-frame image on the external space. The method of claim 20,
The first and second sub-frame images,
Fourier beam converters formed on different regions of the outer space. The method of claim 21,
The first and second sub-frame images,
Fourier beam converters that are images of different parts of the same frame image. A Fourier beam transducer according to claim 1; And
And a light source for emitting the plurality of lights to the Fourier beam converter. The method of claim 23,
The display device further comprises an expander (Eye Pupil expander) for expanding the plurality of light output from the Fourier beam converter. The method of claim 24,
The expander,
A display device through which light corresponding to a reality environment is transmitted. The method of claim 23,
The display apparatus further comprises a spatial light modulator for adding image information to the Fourier beam converter or a plurality of lights emitted from the light source. The method of claim 23,
The display device further comprising a; direction adjusting member for adjusting the incident angle of the plurality of light incident on the Fourier beam converter.

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