Light guide member including diffraction pattern

Abstract

A light guide member according to an embodiment includes at least one of a first light guide, a second light guide, and a third light guide, where each of the first light guide, the second light guide, and the third light guide includes a structure that acts on light of different wavelength ranges, the first light guide including a first substrate and a first structure, the first structure is disposed on the first substrate and acts on light of a first wavelength range, the first wavelength being 380 nm to 500 nm, the first structure being formed by an assembly of a plurality of first unit structures, the structure of the first unit structures including first protrusions protruding in a first direction, the first protrusions protruding in a second direction, and the first protrusions protruding in a second direction. And the first protruding portion is symmetrical with respect to the second direction with a line in the first direction passing through the center of the first unit structure as an axis thereof.

Description

Technical Field

[0001] The present embodiment relates to a light guide member including a diffraction pattern. Background Art

[0002] With the advancement of technology, various types of wearable devices that can be worn on the body have been released recently. Among them, augmented reality (AR) devices are wearable devices in the form of glasses worn on the user's head. AR devices provide visual information through a display. Therefore, users can receive AR services.

[0003] Augmented reality is a technology that mixes real-world information with virtual images by inserting three-dimensional images into the real environment.

[0004] Real-world information may contain information that the user does not need. Alternatively, real-world information may lack information that the user needs. However, augmented reality systems combine the real world and the virtual world. Therefore, the interaction between the real world and the virtual world occurs in real time.

[0005] Unlike virtual reality (VR) devices that block the field of view, augmented reality (AR) devices do not block the field of view when used. In addition, AR devices present a widescreen display in front of the user while being worn on something like ordinary glasses. In addition, from the user's point of view, AR devices can provide an extended reality that combines reality and AR content by utilizing a 360° space. In addition, AR devices can provide users with optimized displays while freeing their hands.

[0006] The augmented reality device includes an optical module. The optical module provides an augmented reality image to a user. For example, the augmented reality device is configured as wearable glasses. In addition, a projection device that projects an image onto the wearable glasses can be combined.

[0007] The light emitted from the projection device passes through the waveguide or AR glasses and enters the user's eyes. As a result, the user can perceive the augmented reality display.

[0008] At the same time, the light emitted from the projection device is diffracted by the waveguide or AR glasses. The diffracted light can then enter the user's eyes. Therefore, the waveguide or AR glasses may include a diffraction pattern. The diffraction pattern may act in a specific wavelength region. However, since the diffraction efficiency is not uniform at all angles, the optical efficiency of the augmented reality device may be reduced.

[0009] Therefore, there is a need for a waveguide or AR glasses that has uniform and high efficiency over the entire angular range while having a wide angular bandwidth. Summary of the invention

[0010] Technical issues

[0011] This embodiment provides a diffraction pattern that enables light of different wavelengths to have uniform efficiency at a wide incident angle. In addition, a light guide member including the diffraction pattern is provided.

[0012] Solution to the problem

[0013] According to an embodiment, the light guide component includes: at least one of a first light guide, a second light guide and a third light guide, wherein each of the first light guide, the second light guide and the third light guide includes a structure that acts on light of different wavelength ranges, the first light guide includes a first substrate and a first structure arranged on the first substrate to act on light of a first wavelength range, the first wavelength is 380nm to 500nm, the first structure is formed as a set of multiple first unit structures, the structure of the first unit structure includes a first protrusion, the first protrusion protrudes along a first direction, and the first protrusion is symmetrical in a second direction about a line of the first direction passing through the center of the first unit structure.

[0014] Beneficial Effects

[0015] A light guide member according to an embodiment includes a plurality of light guides.

[0016] Each of the plurality of light guides includes a structure that operates on light of a specific wavelength band.

[0017] Therefore, each of the plurality of light guides diffracts light of a specific wavelength band.

[0018] The shape of the structure can be controlled. In addition, the thickness of the structure can be controlled. In addition, the size of the unit structure of the structure can be controlled.

[0019] Therefore, light of different wavelengths can be diffracted by different structures, respectively. In addition, each light guide can include structures of different shapes and sizes to have an optimal diffraction efficiency according to the wavelength of the incident light.

[0020] Therefore, the light guide member according to the embodiment may have uniform and high diffraction efficiency within a wide range of incident angles. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a view for explaining the flow of light through the light guide member according to the embodiment.

[0022] Figure 2 is a plan view showing a light guide included in a light guide member according to an embodiment.

[0023] Figure 3 is along Figure 2 A cross-sectional view taken at section AA' in FIG.

[0024] Figures 4 to 8 is a top view showing any one of the light guides according to the embodiment.

[0025] Figures 9 to 13 is a graph for explaining a diffraction angle and a diffraction efficiency of any one of the light guides according to the embodiments.

[0026] Figures 14 to 18 is a top view showing another light guide among the light guides according to the embodiment.

[0027] Figures 19 to 23 is a graph for explaining a diffraction angle and a diffraction efficiency of another light guide among light guides according to an embodiment.

[0028] Fig.24 20 is a view showing a wearable device to which a light guide member according to an embodiment is applied. DETAILED DESCRIPTION

[0029] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0030] However, the technical spirit of the present invention is not limited to some embodiments in the described embodiments, but can be implemented in various forms, and one or more components can be selectively combined or replaced in the embodiments without departing from the scope of the technical spirit of the present invention. In addition, unless explicitly and specifically defined and described, the terms (including technical and scientific terms) used in the embodiments of the present invention can be interpreted as meanings that can be generally understood by those skilled in the art, and commonly used terms, such as terms defined in dictionaries, can be interpreted in consideration of the contextual meaning of the relevant technology. In addition, the terms used in the embodiments of the present invention are used to describe the embodiments, rather than to limit the present invention. In this specification, the singular form may also include the plural form, unless explicitly indicated in the phrase, and when it is described as "at least one (or more) of A, B and C", it may include one or more of all combinations that can use A, B and C combinations. In addition, when describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a) and (b) may be used. These terms are only used to distinguish one component from other components, and the nature, order or sequence of the components are not limited by these terms. In addition, when a component is described as being “connected,” “coupled” or “combined” to another component, it may also include a case where the component is “connected,” “coupled” or “combined” by another component arranged between the component and the other component, as well as a case where the component is directly coupled, connected or combined to another component.

[0031] Furthermore, when it is described as being formed or arranged "on (above)" or "under (below)" each component, it may also include a case where one or more other components are formed or arranged between the two components, and a case where the two components are in direct contact with each other. In addition, when it is expressed as "on (above) or under (below)", from the aspect of a component, it may also include a downward direction as well as an upward direction.

[0032] Meanwhile, the first direction and the second direction described below may be the X-axis direction (left-right direction) or the Y-axis direction (up-down direction), respectively. For example, the first direction may be the X-axis direction, and the second direction may be the Y-axis direction. Alternatively, the first direction may be the Y-axis direction, and the second direction may be the X-axis direction.

[0033] Hereinafter, a light guide element according to an embodiment will be described with reference to the accompanying drawings.

[0034] Figure 1 1 is a view for explaining the flow of light (light rays) through the light guide member according to the embodiment.

[0035] Reference Figure 1 , the light source 10 emits light (rays). For example, the light source 10 may emit laser light. The light passes through the light guide member 1000 and enters the user's eyes. The light source 10 may include a projection device.

[0036] The light source 10 may emit light of different colors. Specifically, the light source 10 may emit light of different wavelengths. For example, the light source 10 may emit a first light, a second light, and a third light. Specifically, the light source 10 may emit a first light (R) of red light, a second light (B) of blue light, and a third light (G) of green light.

[0037] The light guide member 1000 may include a plurality of light guides. For example, the light guide member 1000 may include a first light guide 1100 , a second light guide 1200 , and a third light guide 1300 .

[0038] The first light guide 1100 may include a first diffraction pattern. The second light guide 1200 may include a second diffraction pattern. The third light guide 1300 may include a third diffraction pattern.

[0039] The first diffraction pattern, the second diffraction pattern, and the third diffraction pattern may work only in a specific wavelength region. That is, the first diffraction pattern, the second diffraction pattern, and the third diffraction pattern may have a wavelength selection characteristic. Therefore, the first light, the second light, and the third light may be diffracted in at least one of the first light guide 1100, the second light guide 1200, and the third light guide 1300.

[0040] For example, the first light may be diffracted in the first light guide 1100. The second light may be diffracted in the second light guide 1200. The third light may be diffracted in the third light guide 1300. That is, the first light, the second light, and the third light may be diffracted in different light guides.

[0041] However, this embodiment is not limited thereto. Figure 1 , it is shown that the light guide member 1000 includes the first light guide to the third light guide. However, the light guide member 1000 may omit at least one light guide. For example, the light guide member 1000 may include the first light guide 1100 and the second light guide 1200. That is, the third light guide 1300 may be omitted.

[0042] Thus, the third light may be diffracted in at least one of the first light guide 1100 and the second light guide 1200 .

[0043] The light guide member may be at least one of a waveguide or AR glasses. That is, the light emitted from the light source 10 passes through the waveguide as the light guide member and enters the AR glasses. Therefore, the user can perceive the display. Alternatively, the light emitted from the light source 10 enters the AR glasses as the light guide member. Therefore, the user can perceive the display.

[0044] At the same time, when the light guide member diffracts light having a wide incident angle, the user's visibility can be improved. In addition, the light guide member will have a uniform and high diffraction efficiency within a range of incident angles.

[0045] Hereinafter, a light guide member having uniform and high diffraction efficiency within an incident angle range while having a bandwidth of a wide incident angle will be described.

[0046] Figure 2 and Figure 3 is a view for explaining a light guide of a light guide member according to an embodiment. Figure 2 and Figure 3 Detailed description of the shape of the light guide is given below.

[0047] Reference Figure 2 and Figure 3 , the light guide may include a substrate 100 and a structure 200 .

[0048] The substrate 100 may include a material that can transmit light. For example, the substrate 100 may include glass or plastic. For example, the substrate 100 may include polyethylene terephthalate (PET) or polyimide (PI).

[0049] The substrate 100 may support the structure 200. The substrate 100 may be a waveguide or AR glasses.

[0050] The substrate 100 may include a first surface 1S and a second surface 2S opposite to the first surface 1S. The first surface 1S and the second surface 2S may be defined by a distance from the user's eyes. For example, the first surface 18 may be far from the user's eyes. In addition, the second surface 2S may be close to the user's eyes. For example, when the substrate 100 is an AR glasses, the first surface 1S may be the outer surface of the AR glasses. In addition, the second surface 2S may be the inner surface of the AR glasses.

[0051] The structure 200 may be arranged on the substrate 100. The structure 200 may be arranged on at least one of the first surface 1S and the second surface 2S of the substrate 100. For example, the structure 200 may be arranged on the first surface 1S. Alternatively, the structure 200 may be arranged on the second surface 2S. Alternatively, the structure 200 may be arranged on the first surface 1S and the second surface 2S.

[0052] The structure 200 may include a material that is the same as or similar to that of the substrate 100. Alternatively, the structure 200 may include a material that is different from that of the substrate 100. For example, the structure 200 may include TiOx, HfOx, SiOx, Si, GaAs, or Ge.

[0053] The structure 200 may be a diffraction pattern. Light passing through the light guide may be diffracted by the structure 200. The structure 200 may include a plurality of patterns. Specifically, the structure 200 may include a plurality of patterns spaced apart from each other. The structure 200 may be formed as a metasurface of a free-form shape. Thus, the light guide may diffract light of a specific wavelength region at a set range of diffraction angles.

[0054] The structure 200 may have a width W and a thickness T of a set range. For example, the structure 200 may have a thickness of a set range. For example, the structure 200 may have a similar thickness in the entire region of the substrate 100. In addition, the structure 200 may have a width of a set range. For example, the structure 200 may have different widths in the entire region of the substrate 100. That is, the width of the structure 200 arranged in one region of the substrate 100 and the width of the structure 200 arranged in another region may be different. Therefore, in the entire region of the substrate 100, the structure 200 may have a similar thickness and different widths.

[0055] In addition, the substrate 100 and the structure 200 may have a refractive index within a set range.

[0056] For example, the substrate 100 and the structure 200 may have a refractive index of 1.5 to 4. The substrate 100 and the structure 200 may have the same or different refractive indexes within the refractive index range. For example, the refractive index of the structure 200 may be higher than the refractive index of the substrate 100.

[0057] Meanwhile, the diffraction efficiency of the light guide can be determined by the intensity of the light traveling in the diffraction angle direction relative to the intensity of the incident light. In addition, the intensity of the light passing through the light guide can be determined by the transmittance and the phase change after transmission as a result of the interaction between the incident light and the structure.

[0058] That is, the intensity of light traveling in the diffraction angle direction may vary depending on the shape and size of the structure.

[0059] The light guide member according to the embodiment arranges the structure in a shape having the best diffraction efficiency according to the wavelength of the light entering the light guide. Therefore, the light passing through the light guide member can have uniform and high diffraction efficiency within a wide range of incident angles.

[0060] In the following, reference will be made to Figures 4 to 13 Describe the structure of the first light guide.

[0061] Reference Figures 4 to 8 , the first light guide 1100 may include a first structure 210 .

[0062] Figures 4 to 8 is a top view showing the first light guide 1100. Figures 4 to 8 , the first light guide 1100 may include a first substrate 110 and a first structure 210 .

[0063] The first structure 210 may diffract light in a set range of wavelength bands. Specifically, the first structure 210 may selectively diffract light in at least one wavelength band of red light and green light. That is, the first structure 210 may selectively diffract light in the first wavelength band of red light. Alternatively, the first structure 210 may selectively diffract light in the third wavelength band of green light. Alternatively, the first structure 210 may selectively diffract light in the first wavelength band of red light or light in the third wavelength band of green light.

[0064] Hereinafter, for convenience of explanation, the description will be focused on the case where the first structure 210 selectively diffracts light in the first wavelength band of red light.

[0065] The first substrate 110 may include a first transmission region T and a second transmission region NT defined by the first structure 210. Specifically, the first substrate 110 may include a first transmission region T where the first structure 210 is not arranged and a second transmission region NT where the first structure 210 is arranged. Light passing through the first light guide 1100 may be diffracted by the first transmission region T and the second transmission region NT. Specifically, a phase difference occurs between light passing through the first transmission region T and light passing through the second transmission region NT. In addition, the sum of the phase differences may appear as a diffraction phenomenon.

[0066] The first structure 210 may include a plurality of patterns. For example, the first structure 210 may include a 1-1 pattern P1-1 and a 1-2 pattern P1-2. The 1-1 pattern P1-1 and the 1-2 pattern P1-2 may extend in the second direction 2D. That is, the 1-1 pattern P1-1 and the 1-2 pattern P1-2 may have a width in the first direction 1D and a length in the second direction 2D. In addition, the 1-1 pattern P1-1 and the 1-2 pattern P1-2 may be spaced apart from each other. Specifically, the 1-1 pattern P1-1 and the 1-2 pattern P1-2 may be spaced apart in the first direction 1D.

[0067] The first structure 210 may include a plurality of unit structures. For example, the first structure 210 may include a plurality of first unit structures UN1. When the first substrate 110 is divided into a plurality of unit regions, a structure in which the same shape of the structure is arranged in the plurality of unit regions may be defined as the first unit structure UN1.

[0068] Therefore, the first unit structures UN1 adjacent in the first direction 1D may include the same shape of the first structure 210. For example, one of the first unit structures UN1 adjacent in the first direction 1D may be a 1-1 pattern P1-1. Also, the other first unit structure may be a 1-2 pattern P1-2.

[0069] In addition, the first unit structures UN1 adjacent in the second direction 2D may include the same shape of the first structures 210. For example, all the first unit structures UN1 adjacent in the second direction 2D may be a 1-1 pattern P1-1 or a 1-2 pattern P1-2.

[0070] In addition, the first unit structures UN1 adjacent in the diagonal direction of the first direction 1D and the second direction 2D may include the first structures 210 of the same shape. For example, any one of the first unit structures UN1 adjacent in the diagonal direction may be a 1-1 pattern P1-1. In addition, another first unit structure may be a 1-2 pattern P1-2.

[0071] That is, the first light guide may be a collection of a plurality of first unit structures UN1.

[0072] The first unit structure UN1 may include structures that are symmetrical to each other. For example, the first structure 210 of the first unit structure UN1 may be symmetrical in the second direction 2D. That is, the first structure 210 of the first unit structure UN1 may be symmetrical in the second direction 2D with respect to the first direction 1D.

[0073] Therefore, the first transmission region T and the second transmission region NT of the first unit structure UN1 may be symmetrical in the second direction 2D.

[0074] However, the embodiment is not limited thereto, and the first structure 210 of the first unit structure UN1 may be symmetrical in the first direction 1D. That is, the first structure 210 of the first unit structure UN1 may be symmetrical in the first direction 1D with respect to the second direction 2D.

[0075] Alternatively, the first structure 210 of the first unit structure UN1 may be symmetrical in diagonal directions of the first direction 1D and the second direction 2D.

[0076] Hereinafter, for convenience of explanation, description will be centered on a case where the first structure 210 of the first unit structure UN1 is symmetric in the second direction 2D with respect to the first direction 1D.

[0077] The first structure 210 may have a thickness within a set range. Specifically, the thickness of the first structure 210 may be related to the wavelength of light interacting with the first structure 210 .

[0078] The thickness of the first structure 210 may be smaller than the wavelength of light interacting with the first structure. Specifically, the thickness of the first structure 210 may satisfy Equation 1 shown below.

[0079] [Formula 1]

[0080] first wavelength×0.25≤thickness of first structure<first wavelength×0.75

[0081] (Here, the first wavelength is 380nm to 500nm)

[0082] When the thickness of the first structure 210 satisfies Formula 1, the interaction between the light (ray) entering at a set angle and the first structure increases. Therefore, the diffraction efficiency can be improved.

[0083] However, when the thickness of the first structure 210 is less than 0.25 times the first wavelength, the interaction between the light (light) entering at a set angle and the first structure is reduced. Therefore, the diffraction efficiency may be reduced. In addition, when the thickness of the first structure 210 is greater than 0.75 times the first wavelength, the variation of the diffraction efficiency of the light (light) entering at different angles may increase. Therefore, the diffraction efficiency within a wide range of incident angles may be low. Alternatively, the diffraction efficiency within a wide range of incident angles may be uneven.

[0084] The first unit structure UN1 may have a size within a set range. Specifically, the first unit structure UN1 has a length in the first direction L1-1 and a length in the second direction L1-2. The length in the first direction L1-1 and the length in the second direction L1-2 may have a set range.

[0085] The length in the first direction L1 and the length in the second direction L2 may be the same. That is, the first unit structure UN1 may be formed in a square shape.

[0086] Alternatively, the length in the first direction L1-1 and the length in the second direction L1-2 may be different. For example, the length in the first direction L1-1 may be greater than the length in the second direction L1-2. Alternatively, the length in the first direction L1-1 may be less than the length in the second direction L1-2. That is, the first unit structure UN1 may be formed in a rectangular shape.

[0087] The length L1 - 1 in the first direction and the length L1 - 2 in the second direction may be related to the wavelength of light interacting with the first structure 210 .

[0088] At least one of the length L1-1 in the first direction and the length L1-2 in the second direction may be smaller than the wavelength of light interacting with the first structure. Specifically, the length L1-1 in the first direction and the length L1-2 in the second direction may satisfy Formula 2 shown below.

[0089] [Formula 2]

[0090] first wavelength×0.5≤length L1-1 in the first direction<first wavelength×0.75, or

[0091] first wavelength×0.5≤length L1-2 in the second direction<first wavelength×0.75, or

[0092] first wavelength×0.5≤length L1-1 in the first direction and length L1-2 in the second direction<first wavelength×0.75.

[0093] (Here, the first wavelength is 380nm to 500nm)

[0094] When the length L1-1 in the first direction and the length L1-2 in the second direction satisfy Formula 2, the interaction between the light (ray) entering at a set angle and the first structure increases. Therefore, the diffraction efficiency can be improved.

[0095] However, when the length in the first direction L1-1 and the length in the second direction L1-2 do not satisfy Formula 2, the interaction between the light (ray) entering at a set angle and the first structure is reduced. Therefore, the diffraction efficiency may be reduced.

[0096] Alternatively, the length in the first direction L1 - 1 and the length in the second direction L1 - 2 may be related to the thickness of the first structure 210 .

[0097] At least one of the length in the first direction L1-1 and the length in the second direction L1-2 may be greater than the thickness of the first structure 210. Specifically, the length L1-1 in the first direction and the length L1-2 in the second direction may satisfy Formula 3 shown below.

[0098] [Formula 3]

[0099] The length in the first direction L1-1×0.25≤the thickness of the first structure≤the length in the first direction L1-1×0.75, or

[0100] The length in the second direction L1-2×0.25≤the thickness of the first structure≤the length in the second direction L1-2×0.75, or

[0101] The length L1-1 in the first direction and the length L1-2 in the second direction×0.25≤the thickness of the first structure≤the length L1-1 in the first direction and the length L1-2 in the second direction×0.75.

[0102] When the thickness of the first structure satisfies Formula 3, the interaction between the light (ray) entering at a set angle and the first structure increases. Therefore, the diffraction efficiency can be improved.

[0103] However, when the thickness of the first structure does not satisfy Formula 3, the interaction between light (ray) entering at a set angle and the first structure is reduced. Therefore, the diffraction efficiency may be reduced.

[0104] The first unit structure UN1 may include a first protrusion unit P1. The first protrusion unit P1 may protrude in one direction. Specifically, the first protrusion unit P1 may protrude in a first direction D1. The first protrusion unit P1 may include a curved surface. The first protrusion unit P1 may be formed in a shape in which the width narrows while extending in the protruding direction. Therefore, the width of the first structure 210 of the first unit structure UN1 may decrease while extending in the direction of the first protrusion unit P1.

[0105] In addition, the first protrusion unit P1 may be symmetrical in the second direction D2. That is, the first protrusion unit P1 may be symmetrical in the second direction D2 about a line in the first direction passing through the center of the first unit structure UN1. That is, the first protrusion unit P1 may be symmetrical in the second direction 2D while protruding in the first direction D1.

[0106] The first structure 210 of the first unit structure UN1 may be arranged to have an area of ​​a set range. For example, the area of ​​the first structure 210 may be 50% or more of the total area of ​​the first unit structure UN1. Specifically, the area of ​​the first structure 210 may be 55% or more of the total area of ​​the first unit structure UN1. More specifically, the area of ​​the first structure 210 may be 60% or more of the total area of ​​the first unit structure UN1.

[0107] Furthermore, the first structure 210 of the first unit structure UN1 may have a longest pattern line of a set range. When the first unit structure UN1 is divided into a plurality of pixels, the longest pattern line of the first structure 210 may be defined as a line having the largest number of pixels among lines in the first direction 1D.

[0108] The longest pattern line of the first structure 210 may be 30 pixels or more. Specifically, the longest pattern line of the first structure 210 may be 35 pixels or more.

[0109] In addition, the first structure 210 of the first unit structure UN1 may have a set range of the longest pattern ratio The longest pattern ratio of the first structure 210 may be defined as a ratio of the length of the longest pattern line to the total length of lines having the longest pattern line.

[0110] The longest pattern ratio of the first structure 210 may be 70% or more. Specifically, the longest pattern ratio of the first structure 210 may be 75% or more. In more detail, the longest pattern ratio of the first structure 210 may be 80% or more.

[0111] When the first structure 210 satisfies the ranges of area, longest pattern line, and longest pattern ratio, the interaction between light (ray) entering at a set angle and the first structure increases. Therefore, the diffraction efficiency can be improved.

[0112] However, when the first structure 210 does not meet the ranges of area, longest pattern line, and longest pattern ratio, the interaction between the light (light) entering at a set angle and the first structure is reduced. Therefore, the diffraction efficiency may be reduced. In addition, the ratio of the first structure 210 is increased. Therefore, since the pattern of the first structure 210 can be perceived from the outside, the visibility may be reduced.

[0113] Figures 9 to 13 They are used to explain Figures 4 to 8 A view of the diffraction efficiency of the first light guide of the first unit structure.

[0114] Figures 9 to 13(a) is a graph showing diffraction efficiency according to the incident angle. m=0 means that light without diffraction is transmitted (refracted). m=1 means diffracted light. m=-1 means light that may produce various side effects due to the environment, although diffraction is not the target.

[0115] Figures 9 to 13 (b) is a graph showing the diffraction angle according to the incident angle. m=-1 means the angle at which the -1st order diffracted light travels. m=0 means the angle at which the 0th order diffracted light travels. m=1 means the angle at which the 1st order diffracted light travels.

[0116] Reference Figures 9 to 13 It can be seen that the diffraction m=1 curve has uniform and high diffraction efficiency in the range of -23° to 23°.

[0117] In addition, the lines other than m=-1, m=0 and m=1 represent the sum of the diffraction efficiencies of the -1st order, the 0th order and the 1st order. That is, this means that in addition to the -1st order, the 0th order and the 1st order, there are efficiencies of higher order terms. Figures 9 to 13 , it can be seen that in the range of -23° to 23°, there is an efficiency of higher order terms of about 20% or less.

[0118] That is, it can be seen that the first light guide including the first structure according to the embodiment has uniform and high diffraction efficiency within a wide bandwidth range of a wide incident angle.

[0119] In the following, reference will be made to Figures 14 to 23 Describe the structure of the second light guide.

[0120] Reference Figures 14 to 18 , the second light guide 1200 may include a second structure 220 .

[0121] Figures 14 to 18 is a top view of the second light guide 1200. Figures 14 to 18 , the second light guide 1200 may include a second substrate 120 and a second structure 220 .

[0122] The second structure 220 can diffract light in a set range of wavelength bands. Specifically, the second structure 220 can selectively diffract light in at least one wavelength band of blue light and green light. That is, the second structure 220 can selectively diffract light in the second wavelength band of blue light. Alternatively, the second structure 220 can selectively diffract light in the third wavelength band of green light. Alternatively, the second structure 220 can selectively diffract light in the second wavelength band of blue light or light in the third wavelength band of green light.

[0123] Hereinafter, for convenience of explanation, description will be made focusing on the case where the second structure 220 selectively diffracts light in the second wavelength band of blue light.

[0124] The second substrate 120 may include a first transmission region T and a second transmission region NT formed by the second structure 220. Specifically, the second substrate 120 may include a first transmission region T where the second structure 220 is not arranged and a second transmission region NT where the second structure 220 is arranged. In the transmission region T, light (rays) may be transmitted and diffracted at a set range of angles. Light passing through the second light guide 1200 may be diffracted by the first transmission region T and the second transmission region NT. Specifically, a phase difference occurs between light passing through the first transmission region T and light passing through the second transmission region NT. In addition, the sum of the phase differences may appear as a diffraction phenomenon.

[0125] The second structure 220 may include a plurality of patterns. For example, the second structure 220 may include a 2-1 pattern P2-1 and a 2-2 pattern P2-2. The 2-1 pattern P2-1 and the 2-2 pattern P2-2 may extend in the second direction 2D. That is, the 2-1 pattern P2-1 and the 2-2 pattern P2-2 may have a width in the first direction 1D and a length in the second direction 2D. In addition, the 2-1 pattern P2-1 and the 2-2 pattern P2-2 may be spaced apart from each other. Specifically, the 2-1 pattern P2-1 and the 2-2 pattern P2-2 may be spaced apart in the first direction 1D.

[0126] The second structure 220 may include a plurality of unit structures. For example, the second structure 220 may include a plurality of second unit structures UN2. When the second substrate 120 is divided into a plurality of unit regions, a structure in which the same shape of the structure is arranged in the plurality of unit regions may be defined as a second unit structure UN2.

[0127] Therefore, the second unit structures UN2 adjacent in the first direction 1D may include the same shape of the second structure 220. For example, one of the second unit structures UN2 adjacent in the first direction 1D may be a 2-1 pattern P2-1. In addition, another second unit structure may be a 2-2 pattern P2-2.

[0128] Furthermore, the second unit structures UN2 adjacent in the second direction 2D may include the same-shaped second structures 220. For example, all the second unit structures UN2 adjacent in the second direction 2D may be a 2-1 pattern P2-1 or a 2-2 pattern P2-2.

[0129] In addition, the second unit structures UN2 adjacent in the diagonal direction of the first direction 1D and the second direction 2D may include the second structures 220 of the same shape. For example, any one of the second unit structures UN2 adjacent in the diagonal direction may be a 2-1 pattern P2-1. In addition, another second unit structure may be a 2-2 pattern P2-2.

[0130] That is, the second light guide may be a collection of a plurality of second unit structures UN2.

[0131] The second unit structure UN2 may include structures that are symmetrical to each other. For example, the second structure 220 of the second unit structure UN2 may be symmetrical in the second direction 2D. That is, the second structure 220 of the second unit structure UN2 may be symmetrical in the second direction 2D with respect to the first direction 1D.

[0132] Therefore, the first transmission region T and the second transmission region NT of the second unit structure UN2 may be symmetrical in the second direction 2D.

[0133] However, the embodiment is not limited thereto, and the second structure 220 of the second unit structure UN2 may be symmetrical in the first direction 1D. That is, the second structure 220 of the second unit structure UN2 may be symmetrical in the first direction 1D with respect to the second direction 2D.

[0134] Alternatively, the second structure 220 of the second unit structure UN2 may be symmetrical in a diagonal direction of the first direction 1D and the second direction 2D.

[0135] Hereinafter, for convenience of explanation, description will be centered on a case where the second structure 220 of the second unit structure UN2 is symmetric in the second direction 2D with respect to the first direction 1D.

[0136] The second structure 210 may have a thickness within a set range. Specifically, the second structure 220 may be related to the wavelength of light that interacts with the second structure 220.

[0137] The thickness of the second structure 220 may be smaller than the wavelength of light interacting with the second structure. Specifically, the thickness of the second structure 220 may satisfy Formula 4 shown below.

[0138] [Formula 4]

[0139] second wavelength×0.25≤thickness of second structure<second wavelength×0.5

[0140] (Here, the second wavelength is 600nm to 700nm)

[0141] When the thickness of the second structure 220 satisfies Formula 4, the interaction between the light (ray) entering at a set angle and the second structure increases. Therefore, the diffraction efficiency can be improved.

[0142] However, when the thickness of the second structure 220 is less than 0.25 times the second wavelength, the interaction between the light (light) entering at a set angle and the second structure is reduced. Therefore, the diffraction efficiency may be reduced. In addition, when the thickness of the second structure 220 is greater than 0.5 times the second wavelength, the variation of the diffraction efficiency of the light (light) entering at different angles may increase. Therefore, the diffraction efficiency within a wide range of incident angles may be low. Alternatively, the diffraction efficiency within a wide range of incident angles may be uneven.

[0143] The second unit structure UN2 may have a size within a set range. Specifically, the second unit structure UN2 has a length in the first direction L2-1 and a length in the second direction L2-2. The length in the first direction L2-1 and the length in the second direction L2-2 may have a set range.

[0144] The length in the first direction L2-1 and the length in the second direction L2-2 may be the same. That is, the second unit structure UN2 may be formed in a square shape.

[0145] Alternatively, the length in the first direction L2-1 and the length in the second direction L2-2 may be different. For example, the length in the first direction L2-1 may be greater than the length in the second direction L2-2. Alternatively, the length in the first direction L2-1 may be less than the length in the second direction L2-2. That is, the second unit structure UN2 may be formed in a rectangular shape.

[0146] The length in the first direction L2 - 1 and the length in the second direction L2 - 2 may be related to the wavelength of light interacting with the second structure 220 .

[0147] At least one of the length in the first direction L2-1 and the length in the second direction L2-2 may be less than the wavelength of light interacting with the second structure. Specifically, the length L2-1 in the first direction and the length L2-2 in the second direction may satisfy Formula 5 shown below.

[0148] [Formula 5]

[0149] The second wavelength×0.5≤the length L2-1 in the first direction<the second wavelength×0.75, or

[0150] second wavelength×0.5≤length L2-2 in the second direction<second wavelength×0.75, or

[0151] second wavelength×0.5≤lengths L2-1 and L2-2 in the first direction and the second direction<second wavelength×0.75.

[0152] (Here, the second wavelength is 600nm to 700nm)

[0153] When the length in the first direction L2-1 and the length in the second direction L2-2 satisfy Formula 5, the interaction between the light (ray) entering at a set angle and the second structure increases. Therefore, the diffraction efficiency can be improved.

[0154] However, when the length in the first direction L2-1 and the length in the second direction L2-2 do not satisfy Formula 5, the interaction between the light (ray) entering at a set angle and the second structure is reduced. Therefore, the diffraction efficiency may be reduced.

[0155] Alternatively, the length in the first direction L2 - 1 and the length in the second direction L2 - 2 may be related to the thickness of the second structure 220 .

[0156] At least one of the length in the first direction L2-1 and the length in the second direction L2-2 may be greater than the thickness of the second structure 220. Specifically, the length L2-1 in the first direction and the length L2-2 in the second direction may satisfy Formula 6 shown below.

[0157] [Formula 6]

[0158] The length L2-1×0.5 in the first direction ≤ the thickness of the second structure ≤ the length in the first direction×0.75, or

[0159] The length in the second direction L2-2×0.5≤the thickness of the second structure≤the length in the second direction×0.75, or

[0160] The length L2-1 and L2-2 in the first and second directions×0.5≤the thickness of the second structure≤the length L2-1 and L2-2 in the first and second directions×0.75.

[0161] When the thickness of the second structure satisfies Formula 6, the interaction between the light (light ray) entering at a set angle and the second structure increases. Therefore, the diffraction efficiency can be improved.

[0162] However, when the thickness of the second structure does not satisfy Formula 6, the interaction between the light (light ray) entering at a set angle and the second structure is reduced. Therefore, the diffraction efficiency may be reduced.

[0163] The second unit structure UN2 may include a second protrusion unit P2. The second protrusion unit P2 may protrude in one direction. Specifically, the second protrusion unit P2 may protrude in the first direction D1. The second protrusion unit P2 may include a curved surface. The width of the second protrusion unit P2 may narrow while extending in the protruding direction. Therefore, the width of the second structure 220 of the second unit structure UN2 may decrease while extending in the direction of the second protrusion unit P2.

[0164] In addition, the second protrusion unit P2 may be symmetrical in the second direction D2. That is, the second protrusion unit P2 may be symmetrical in the second direction D2 about a line in the first direction passing through the center of the second unit structure UN2. That is, the second protrusion unit P2 may be symmetrical in the second direction 2D while protruding in the first direction D1.

[0165] The second structure 220 of the second unit structure UN2 may be arranged to have an area of ​​a set range. For example, the area of ​​the second structure 220 may be 50% or more of the total area of ​​the second unit structure UN2. Specifically, the area of ​​the second structure 212 may be 55% or more of the total area of ​​the second unit structure UN2. More specifically, the area of ​​the second structure 220 may be 60% or more of the total area of ​​the second unit structure UN2.

[0166] Furthermore, the second structure 220 of the second unit structure UN2 may have a longest pattern line of a set range. When the second unit structure UN1 is divided into a plurality of pixels, the longest pattern line of the second structure 220 may be defined as a line having the largest number of pixels among lines in the first direction 1D.

[0167] The longest pattern line of the second structure 220 may be 30 pixels or more. Specifically, the longest pattern line of the second structure 220 may be 35 pixels or more. Specifically, the longest pattern line of the second structure 220 may be 40 pixels or more.

[0168] In addition, the second structure 220 of the second unit structure UN2 may have a set range of the longest pattern ratio The longest pattern ratio of the second structure 220 may be defined as a ratio of the length of the longest pattern line to the total length of the lines having the longest pattern line.

[0169] The longest pattern ratio of the second structure 210 may be 70% or more. Specifically, the longest pattern ratio of the second structure 210 may be 75% or more. In more detail, the longest pattern ratio of the second structure 220 may be 80% or more. In more detail, the longest pattern ratio of the second structure 220 may be 85% or more.

[0170] When the second structure 220 satisfies the ranges of area, longest pattern line and longest pattern ratio, the interaction between light (ray) entering at a set angle and the second structure increases. Therefore, the diffraction efficiency can be improved.

[0171] However, when the second structure 220 does not satisfy the ranges of area, longest pattern line and longest pattern ratio, the interaction between light (ray) entering at a set angle and the second structure is reduced. Therefore, the diffraction efficiency may be reduced.

[0172] Figures 19 to 23 They are used to explain Figures 14 to 18 View of the diffraction efficiency of the second light guide of the second unit structure.

[0173] Figures 19 to 23 (a) is a graph showing diffraction efficiency according to the incident angle. m=0 means that light without diffraction is transmitted (refracted). m=1 means diffracted light. m=-1 means light that may produce various side effects due to the environment, although diffraction is not the target.

[0174] Figures 19 to 23 (b) is a graph showing the diffraction angle according to the incident angle. m=-1 means the angle at which the -1st order diffracted light travels. m=0 means the angle at which the 0th order diffracted light travels. m=1 means the angle at which the 1st order diffracted light travels.

[0175] Reference Figures 19 to 23 It can be seen that the diffraction m=1 curve has uniform and high diffraction efficiency in the range of -23° to 23°.

[0176] In addition, the lines other than m=-1, m=0 and m=1 refer to the sum of the diffraction efficiencies of the -1st order, the 0th order and the 1st order. That is, this means that in addition to the -1st order, the 0th order and the 1st order, there are efficiencies of higher order terms. Figures 19 to 23 , it can be seen that in the range of -23° to 23°, there is an efficiency of higher order terms of about 20% or less.

[0177] That is, it can be seen that the second light guide including the second structure according to the embodiment has uniform and high diffraction efficiency within a wide bandwidth range of incident angles.

[0178] In the following, reference will be made to Fig.24 An example of a display device including the light guide member 1000 according to the embodiment is described.

[0179] Reference Fig.24 The light guide member 1000 according to the embodiment may be applied to a wearable display device. Specifically, the light guide member 1000 may be applied to a wearable display device worn on the head or ear of a human body.

[0180] For example, the display device 3000 may be an augmented reality device.

[0181] The display device 3000 may include a wearable unit 3100 , an optical member 15 , and a display unit 3200 .

[0182] The light guide member 1000 according to the embodiment may be adjacent to the optical member 15 including the light source. That is, the light guide member 1000 may be a waveguide adjacent to the optical member 15.

[0183] Alternatively, the light guide member 1000 according to the embodiment may be adjacent to the display unit 3200. Specifically, the light guide member 1000 according to the embodiment may be the display unit 3200. More specifically, the light guide member 1000 according to the embodiment may be AR glasses on which a display is shown.

[0184] The wearable unit 3100 may extend in one direction. The wearable unit 3100 may be worn on the user's body. For example, the wearable unit 3100 is worn on the user's head or ear. Therefore, the display device 3000 may be fixed to the user's body.

[0185] The optical member 15 may be connected to the wear unit 3100. The optical member 15 may be adjacent to the display unit 3200. The optical member 15 may transmit light having a scanned image in the direction of the display unit 3200. The light passing through the display unit 3200 may be transmitted to the user's eyes.

[0186] Therefore, the user can perceive the augmented reality including the virtual reality and the actual reality through the optical member.

[0187] The features, structures, effects, etc. described above in the embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. In addition, the features, structures, effects, etc. illustrated in each embodiment may also be combined or modified and implemented by those skilled in the art in other embodiments. Therefore, the contents related to such combinations and modifications should be interpreted as being included within the scope of the present invention.

[0188] In addition, although the above description is focused on the embodiments, these are only examples and do not limit the present invention. Those skilled in the art will recognize that various modifications and applications not illustrated above are possible without departing from the basic features of the present embodiment. For example, each component specifically shown in the embodiment can be modified to implement. In addition, the differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

Claims

1. A light guide member, comprising: at least one light guide among the first light guide, the second light guide and the third light guide, wherein Each of the first light guide, the second light guide and the third light guide comprises a structure that is responsive to light of a different wavelength range, The first light guide comprises a first substrate and a first structure, the first structure being arranged on the first substrate to act on light of a first wavelength range, The first wavelength is 380nm to 500nm, The first structure is formed as a collection of a plurality of first unit structures, The structure of the first unit structure includes a first protrusion, The first protrusion protrudes along a first direction, and The first protrusion is symmetrical in the second direction with respect to a line in the first direction passing through the center of the first unit structure.

2. The light guide member according to claim 1, wherein The structure of the first unit structure is symmetrical in the second direction.

3. The light guide member according to claim 1, wherein The thickness of the first structure satisfies Formula 1, [Formula 1] The first wavelength×0.25≤the thickness of the first structure<the first wavelength×0.

75.

4. The light guide member according to claim 1, wherein The length of the first structure in the first direction and the length of the first structure in the second direction satisfy Formula 2, [Formula 2] first wavelength×0.5≤length in the first direction<first wavelength×0.75, or first wavelength×0.5≤length in the second direction<first wavelength×0.75, or first wavelength×0.5≤length in the first direction and the second direction<first wavelength×0.

75.

5. The light guide member according to claim 1, wherein The length of the first structure in the first direction and the length of the first structure in the second direction satisfy Formula 3, [Formula 3] The length in the first direction×0.25≤the thickness of the first structure≤the length in the first direction×0.75, or The length in the second direction×0.25≤the thickness of the first structure≤the length in the second direction×0.75, or The length in the first direction and the second direction×0.25≤the thickness of the first structure≤the length in the first direction and the second direction×0.

75. The light guide member according to claim 1 , wherein: The first structure includes a 1-1 pattern and a 1-2 pattern spaced apart from each other in the first direction, wherein the 1-1 pattern and the 1-2 pattern have a width in the first direction and a length in the second direction, and any one of the adjacent first unit structures in the first direction is the 1-1 pattern, and the other first unit structure is the 1-2 pattern.

7. The light guide member according to claim 1, wherein The first structure of the first unit structure has a longest pattern ratio of 70% or more, and the longest pattern ratio is defined as a ratio of a length of a longest pattern line to a total length of lines having the longest pattern line.

8. The light guide member according to claim 1, wherein The second light guide comprises a second substrate and a second structure, the second structure being arranged on the second substrate to act on light of a second wavelength range, The second wavelength is 600nm to 700nm, The second structure is formed as a collection of a plurality of second unit structures, The structure of the second unit structure includes a second protrusion, The second protrusion protrudes along the first direction, and The second protrusion is symmetrical in the second direction with respect to a line in the first direction passing through a center of the second unit structure.

9. The light guide member according to claim 8, wherein The thickness of the second structure satisfies Formula 4, [Formula 4] The second wavelength×0.25≤the thickness of the second structure<the second wavelength×0.

5.

10. The light guide member according to claim 8, wherein The length of the second structure in the first direction and the length of the second structure in the second direction satisfy Formula 5, [Formula 5] second wavelength×0.5≤length in the first direction<second wavelength×0.75, or second wavelength×0.5≤length in the second direction<second wavelength×0.75, or The second wavelength×0.5≤the length in the first direction and the second direction<the second wavelength×0.75.

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