KR102353768B1 - Diffractive light guide plate and display device including the same - Google Patents

Abstract

An embodiment according to an aspect of the present invention includes a light guide unit for guiding light; a first diffraction optical element having a linear grating repeatedly formed at a predetermined pitch so that light output from a light source is input and guided on the light guide unit to diffract the input light; and a first imaginary linear pattern disposed on one surface of the light guide part in a region distinct from the region in which the first diffractive optical element is disposed, and arranged repeatedly at a predetermined pitch along the first direction, in the first direction; A second diffractive optical element having a two-dimensional pattern provided in a region where a second virtual linear pattern that is repeatedly arranged at a predetermined pitch along another second direction intersects each other, wherein the horizontal cross section of the two-dimensional pattern is The diffractive light guide plate has an elliptical shape, and an angle formed by a major axis of the elliptical shape perpendicular to an extension direction of the linear grating included in the first diffractive optical element is less than 20°.

Description

Diffraction light guide plate and display device including same

The present invention relates to a diffractive light guide plate and a display device including the diffractive light guide plate.

Recently, as interest in display units that implement Augmented Reality (AR), Mixed Reality (MR), or Virtual Reality (VR) has grown, research on display units implementing them has been actively conducted. there is a trend A display unit that implements augmented reality, mixed reality, or virtual reality includes a diffractive light guide plate that uses a diffraction phenomenon based on the wave nature of light.

1 is a diagram schematically illustrating a diffraction light guide plate according to the related art.

The diffraction light guide plate 10 includes a light guide unit 11 and a plurality of diffractive optical elements 12, 13, and 14 provided on one or the other side of the light guide unit 11 and having a plurality of linear grating patterns. can do. Specifically, the diffraction light guide plate 10 includes an input diffraction optical element 12 through which the light output through the micro light source output element P is input and guided on the light guide unit 11, and the light guide unit 11. It is optically coupled to the input diffractive optical element 12 through the input diffraction optical element 12, and by diffracting the light received from the input diffractive optical element 12, one-dimensional expansion in the first direction (x-axis direction in FIG. 1) can be made. It is optically coupled with the intermediate diffraction optical element 13 through the intermediate diffraction optical element 13 and the light guide unit 11 to allow the light received from the intermediate diffraction optical element 13 to be diffracted in the second direction ( It may include an output diffraction optical element 14 that is output from the light guide unit 11 while being extended in the y-axis direction (in the y-axis direction in FIG. 1 ) to be directed toward the user's pupil.

The main optical path for the light output through the micro light source output element P to reach the user's pupil is the input diffractive optical element 12 - the intermediate diffractive optical element 13 - the output diffractive optical element 14 - the user's pupil. Since it is in the order of pupils, the size of the optical image output from the light guide unit 11 through the output diffractive optical element 14 depends on the area occupied by the output diffractive optical element 14 .

On the other hand, in the case of the diffractive light guide plate according to the prior art, since the single input diffractive optical element 12, the single intermediate diffractive optical element 13, and the single output diffractive optical element 14 are disposed separately from each other on the light guide unit 11, , the area occupied by the output diffractive optical element 14 on the light guide unit 11 is limited to the area excluding the area occupied by the input diffractive optical element 12 and the intermediate diffractive optical element 13 on the light guide unit 11. Inevitably, there was a limit to outputting a larger optical image.

In order to solve this limitation, a diffractive light guide plate having a structure as shown in FIG. 2 may be considered.

2 shows a diffractive light guide plate including a light guide unit 21, an input diffractive optical element 22, and two diffractive optical elements 23 and 24 that are in contact with each other having different linear grating patterns.

3A is a plan view schematically illustrating an example of a light path traveling through the diffractive light guide plate shown in FIG. 2 , and FIG. 3B is a schematic plan view illustrating another example of a light path traveling through the diffraction light guide plate shown in FIG. 2 . It is one floor plan.

The light guide unit 21 guides light from the inside using total internal reflection.

The input diffraction optical element 22 may diffract the input light L1 , L1a , L1b so that the light L1 , L1a , L1b output from the light source is input and guided on the light guide unit 21 .

The two diffractive optical elements 23 and 24 may be configured to receive the diffracted lights L2a and L2b, and the received light may be one-dimensionally expanded by diffraction. The diffracted light L2a, L2b received from the input diffraction optical element 22 is partially diffracted while passing through the other diffractive optical elements 23 and 24 to change the optical path, and the rest can be totally reflected in the existing optical path. , since the light initially received from the input diffraction optical element 22 can be divided into a plurality of beams L3a and L3b while the diffraction is performed a plurality of times at a point spaced apart in a specific direction, so that one-dimensional expansion is eventually made can

Each of the two diffractive optical elements 23 and 24 receives the light L3b and L3a extended from the other diffractive optical element 24 and 23, and the received light L3b, L3a is diffracted by the light guide unit 21 ) can be configured to output from. On the other hand, each of the two diffractive optical elements 23 and 24 may also receive the light L3b and L3a extended from the other diffractive optical elements 24 and 23 and expand the received light one-dimensionally by diffraction. . At this time, based on the light receiving side C of each of the two diffractive optical elements 23 and 24, the plurality of beams L3b and L3a formed by the light expanded by the other diffractive optical elements 24 and 23 are spaced apart. Since the direction in which the plurality of beams L4b and L4a extended by the two diffractive optical elements 23 and 24 based on the single beam L3b and L3a are spaced apart cross each other, eventually the input diffraction from the light source Based on the light L1a and L1b received by the optical element 120, a two-dimensional expansion is made.

Each of the two diffractive optical elements 23 and 24 receives the light L3b and L3a extended from the other diffractive optical elements 24 and 23, and the light receiving side C of the other diffractive optical element 24, 23 receives light It may be configured to be in contact with the side (C). The light output from the light source is output from the light guide unit 110 through the input diffractive optical element 22 - the two diffractive optical elements 23 and 24 - the other diffractive optical elements 24 and 23. In this way, the light guide unit The light output from 110 may be collected by the other diffractive optical elements 24 and 23, respectively, to form one image light.

That is, since both of the two diffractive optical elements 23 and 24 are used as output diffractive optical elements, as shown in FIG. 1, an image with a larger viewing angle while using space more efficiently than when a single output diffractive optical element is used. light can be formed.

4 is a cross-sectional view taken along line III-III' of the diffractive light guide plate shown in FIGS. 3A and/or 3B.

Light diffracted through each of the two diffractive optical elements 23 and 24 and output from the light guide unit 21 may be output at a predetermined emission angle (θ, θ') with respect to one surface of the light guide unit 21 . have. 4, the light L4a that is diffracted and output by the diffractive optical element 23 located on the upper side has a predetermined emission angle θ with respect to one surface of the light guide unit 21 and is tilted downward and is output. , the light L4b that is diffracted and output by the diffractive optical element 24 located below has a predetermined emission angle θ' with respect to one surface of the light guide unit 21 and may be output by being inclined upward.

At a position spaced apart a predetermined distance from one surface of the light guide unit 21, the light L4a diffracted and output by the diffractive optical element 23 located on the upper side and the diffraction optical element 24 located on the lower side are diffracted and output The light L4b to be formed forms an intersecting region I that intersects with each other. If the distance from one surface of the light guide unit 21 is as far as the eye relief where the user's pupil is located, the user's pupil should be located in the intersection region I, so that the user sees the darkest part of the entire region Normal image light can be recognized without If the user's pupil is located in the area A located above the intersection area I, the light L4b that is diffracted and output by the diffractive optical element 24 located at the lower side cannot be recognized by the user. The image light viewed by Ⅲ-Ⅲ' may look dark downward based on the cross-section of the line III-III'. Conversely, when the user's pupil is located in the region B located below the intersection region I, the light L4a that is diffracted and output by the diffractive optical element 23 located at the upper side cannot be recognized by the user. The image light viewed by Ⅲ-Ⅲ' may appear dark upwards based on the cross-section of the line III-III'.

Users who use a display unit having a diffractive light guide plate may have various positions at which the pupil can be located based on the vertical direction of one side of the light guide unit due to individual physical characteristics. Accordingly, there is a need for a structure of a diffractive light guide plate capable of forming the vertical crossing region I related to the eye motion box, which is a region in which normal image light can be viewed, vertically long.

The above-mentioned background art is technical information that the inventor possessed for the derivation of the embodiments of the present invention or acquired in the process of derivation, and it cannot be said that it is necessarily known technology disclosed to the general public prior to the filing of the embodiments of the present invention. none.

An object of the present invention is to provide a diffractive light guide plate capable of forming a large viewing angle and i-motion box, and a display device including the diffractive light guide plate.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

An embodiment according to an aspect of the present invention includes a light guide unit for guiding light; a first diffraction optical element having a linear grating repeatedly formed at a predetermined pitch so that light output from a light source is input and guided on the light guide unit to diffract the input light; and a first imaginary linear pattern disposed on one surface of the light guide part in a region distinct from the region in which the first diffractive optical element is disposed, and arranged repeatedly at a predetermined pitch along the first direction, in the first direction; A second diffractive optical element having a two-dimensional pattern provided in a region where a second virtual linear pattern that is repeatedly arranged at a predetermined pitch along another second direction intersects each other, wherein the horizontal cross section of the two-dimensional pattern is The diffractive light guide plate has an elliptical shape, and an angle formed by a major axis of the elliptical shape perpendicular to an extension direction of the linear grating included in the first diffractive optical element is less than 20°.

In this embodiment, the two-dimensional pattern may be formed to protrude from one surface of the light guide part.

In this embodiment, the protrusion height of the two-dimensional pattern may be 0.084 to 0.113 times the wavelength of the light output from the light source.

In this embodiment, the long axis of the elliptical shape may be 0.50 to 0.921 times the pitch of the linear grid and the linear pattern.

In this embodiment, the short axis of the elliptical shape may be 0.084 to 0.113 times the pitch of the linear grid and the linear pattern.

In this embodiment, the linear grating and the linear pattern have a size inversely proportional to their pitch and a grating vector defined in a direction perpendicular to a direction in which the linear grating and the linear pattern extend, and the first diffractive optical element A sum of the grating vectors of each of the linear grating, the first linear pattern, and the second linear pattern of the second diffractive optical element may have a magnitude of zero.

In this embodiment, the linear grating of the first diffractive optical element, the first linear pattern of the second diffractive optical element, and the grating vector of each of the second linear pattern may have the same size.

In this embodiment, the linear grating of the first diffractive optical element, the grating vector of each of the first linear pattern and the second linear pattern of the second diffractive optical element may form an angle of 60° with each other.

An embodiment according to another aspect of the present invention comprises: a light source for outputting image light forming an image; and a diffractive light guide plate according to an aspect of the present invention.

According to an embodiment of the present invention, the light received from the first diffractive optical element is expanded by each of the first and second gratings formed by a two-dimensional pattern disposed over the entire area of the second diffractive optical element, and Since the image light is output, the viewing angle can be widened, and the i-motion box is also formed wide, so that it can respond widely to the pupils of users having various body conditions.

1 is a diagram schematically illustrating a diffraction light guide plate according to the related art.
FIG. 2 shows a diffractive light guide plate including a light guide unit, an input diffractive optical element, and two diffractive optical elements facing each other with different linear grating patterns.
3A is a plan view schematically illustrating an example of an optical path traveling through the diffraction light guide plate shown in FIG. 2 .
3B is a plan view schematically illustrating another example of an optical path traveling through the diffraction light guide plate shown in FIG. 2 .
4 is a cross-sectional view taken along line IV-IV' of the diffractive light guide plate shown in FIGS. 3A and/or 3B.
5 is a diagram schematically illustrating a diffraction light guide plate according to an aspect of the present invention.
FIG. 6 is a view illustrating a portion of a second diffractive optical element region of the diffractive light guide plate shown in FIG. 5 .
7A is a plan view of a linear grating included in a first diffractive optical element, FIG. 7B is a plan view of a first linear pattern on a second diffractive optical element, and FIG. 7C is a plan view of a second linear pattern on a second diffractive optical element .
8 is a diagram illustrating a combination of grating vectors of a linear grating of a first diffractive optical element, a first linear pattern and a second linear pattern of a second diffractive optical element included in the diffractive light guide plate according to an aspect of the present invention .
9A to 9K are diagrams illustrating the uniformity of light quantity distribution based on simulation results of light output according to the horizontal and vertical lengths and protrusion heights of a two-dimensional pattern in a predetermined region of the second diffractive optical element.
9L to 9N are diagrams illustrating the uniformity of light quantity distribution based on simulation results of light output along the horizontal length direction of the two-dimensional pattern in a predetermined region of the second diffractive optical element.
10A is an image obtained by capturing light output from a second diffractive optical element of an embodiment of a diffractive light guide plate according to an aspect of the present invention, and FIG. 10B is a second diffraction example of a diffractive light guide plate having a circular two-dimensional pattern horizontal cross section It is an image obtained by capturing the light output from the optical element.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. On the other hand, the terms used herein are for the purpose of describing the embodiments and are not intended to limit the present invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, "comprises" and/or "comprising" refers to the presence of one or more other components, steps, operations and/or elements mentioned. or addition is not excluded. Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

In this specification, the term “light guide unit” may be defined as a structure for guiding light from the inside using total internal reflection. A condition for total internal reflection is that the refractive index of the light guide unit must be greater than that of the surrounding medium adjacent to the surface of the light guide unit. The light guide unit may be formed of a glass and/or plastic material, and may be transparent or translucent. The light guide unit may be formed in a plate type and in various layouts. Here, the term "plate" means a three-dimensional structure having a predetermined thickness between one surface and the other surface opposite to it, the one surface and the other surface may be a substantially flat plane, but at least one of the one surface and the other surface is It may be formed by being curved one-dimensionally or two-dimensionally. For example, the plate-type light guide part may be one-dimensionally curved so that one surface and/or the other surface may have a shape corresponding to some of the side surfaces of the cylinder. However, the curvature formed by the curvature preferably has a sufficiently large radius of curvature to facilitate total internal reflection to guide light on the light guide unit.

In this specification, the term "diffraction optical element" may be defined as a structure for diffracting light on a light guide unit to change an optical path. Here, the "diffraction optical element" may refer to a portion in which a linear grating oriented in one direction is arranged in a predetermined direction on the light guide unit to form a predetermined area while having a pattern. As another example, the term "diffraction optical element" may refer to a portion in which a protruding pattern protruded on one surface of the light guide unit or a concave pattern formed concave on one surface of the light guide part is arranged according to a predetermined rule to form a predetermined area.

As used herein, the term “linear grating” refers to a protrusion shape having a predetermined height on the surface of the light guide part (ie, a embossed pattern) and/or a groove shape having a predetermined depth on the surface of the light guide part (ie, an intaglio pattern) ) can mean Here, the alignment direction of the linear grating can be freely designed so that the optical path can be changed in an intended direction through diffraction by the diffractive optical element.

5 to 8 , the diffraction light guide plate 100 may include a light guide unit 110 , a first diffraction optical element 120 , and a second diffraction optical element 130 .

The light guide unit 110 may guide light from the inside using total internal reflection.

The first diffractive optical element 120 may diffract the input light so that the light output from the light source is input and guided on the light guide unit 110 . The first diffractive optical element 120 may include a linear grating 121 repeatedly formed at a predetermined pitch.

The input diffractive optical element 120 may be disposed on one surface 110a or the other surface 110b of the light guide unit 110 .

The second diffractive optical element 130 may be disposed on one surface 110a or the other surface 110b of the light guide unit 110 in a region distinct from the region in which the first diffractive optical element 120 is disposed.

In the region where the second diffractive optical element 130 is disposed, a virtual first linear pattern L1 repeatedly arranged at a predetermined pitch along the first direction and a predetermined pitch along a second direction different from the first direction A region in which the repeated virtual second linear patterns L2 intersect each other may be defined. The first direction may be defined as a direction perpendicular to the direction in which the first linear pattern L1 extends, and the second direction may be defined as a direction perpendicular to the direction in which the second linear pattern L2 extends.

The first diffractive optical element 120 may include a one-dimensional pattern as the linear grating 121 , while the second diffractive optical element 130 may include a two-dimensional pattern 131 provided in the intersecting region. Here, the two-dimensional pattern may be a protrusion pattern formed to protrude on the one surface 110a or the other surface 110b of the light guide unit, or a concave pattern formed to be concave. In this embodiment, the two-dimensional pattern will be mainly described as a protrusion pattern.

Since the two-dimensional patterns 131 are provided in an intersecting region where the first linear pattern L1 and the two-linear pattern L2 intersect, the two-dimensional patterns 131 are first parallel to the first linear pattern L1. A second grid L2' parallel to the second linear pattern L2 may be formed while configuring the grid L1'.

Each of the first grating L1' and the second grating L2' receives light from the first diffraction optical element 120, and the received light is diffracted toward different types of gratings L2' and L1'. It can be configured to In addition, each of the first grating L1' and the second grating L2' receives the light diffracted from the first diffraction optical element 120, and the received light is configured to be one-dimensionally expanded by diffraction. can be A portion of the diffracted light received from the first diffraction optical element 120 is diffracted while passing through the first grating L1' and/or the second grating L2' to change an optical path, and the rest is an existing optical path Since the light initially received from the input diffraction optical element 120 can be divided into a plurality of beams while being diffracted a plurality of times at a point spaced apart in a specific direction, eventually one-dimensional expansion can be achieved. have.

Each of the first grating L1' and the second grating L2' receives light extended from different types of gratings L2' and L1', and the received light is outputted from the light guide unit 110 by diffraction. It can be configured to be On the other hand, each of the first grating L1' and the second grating L2' also receives light extended from different types of gratings L2' and L1' and expands the received light one-dimensionally by diffraction. can At this time, the direction in which the plurality of beams received from the first diffraction optical element 120 and expanded by the first grating L1 ′ and/or the second grating L2 ′ are spaced apart from each other is a different type The directions in which the plurality of beams received from the gratings L2' and L1' and extended by the first grating L1' and/or the second grating L2' intersect each other, so eventually the first The light output by the plurality of beams extended by the grating L1' and the second grating L2' is two-dimensionally expanded based on the light received by the first diffractive optical element 120 from the light source. can be dealt with

Each of the linear grating 121 and the linear patterns L1 and L2 is a lattice vector defined by a 'size' inversely proportional to the respective pitches P1, P2, and P3 and a 'direction' perpendicular to the direction in which the linear gratings extend. It can have (V1, V2, V3). Here, the linear patterns L1 and L2 may be replaced with lattices L1' and L2'. The magnitudes of the lattice vectors V1, V2, and V3 may be defined by Equation 1 below.

[Equation 1]

는 격자 벡터 크기를 의미하며, P 는 선형 격자, 선형 패턴 및/또는 격자들의 피치를 의미한다.here,

denotes the grating vector size, and P denotes the linear grating, the linear pattern and/or the pitch of the gratings.

The linear grating 121 of the first diffractive optical element 120, the first linear pattern L1 and the second linear pattern L2 of the second diffractive optical element 130, respectively, grating vectors V1, V2, V3 The sum of has a magnitude of 0. Similarly, the linear grating 121 of the first diffractive optical element 120, the first grating L1' and the second grating L2' of the second diffractive optical element 130, respectively, grating vectors V1, V2, The sum of V3) has a magnitude of zero.

At this time, each of the grating vectors V1 and V2 of the linear grating 121 of the first diffractive optical element 120 and the first linear pattern L1 and the second linear pattern L2 of the second diffractive optical element 130 . , V3) have the same size as each other, and the linear grating 121 of the first diffractive optical element 120, the first linear pattern L1 and the second linear pattern L2 of the second diffractive optical element 130, respectively It is preferable that the lattice vectors V1, V2, V3 form an angle of 60° to each other. This is because each of the diffractive optical elements 120 and 130 can all be molded by a single mold having a grating pattern of the same pitch.

As an embodiment, the first diffractive optical element 120 has a linear grating 121 that forms an angle of 90° with a horizontal line H parallel to the x-axis, as shown in FIG. 7A , and the second diffractive optical element 130 is shown in FIG. 7C with the first linear pattern L1 and/or the first lattice L1 ′ forming an angle of −30° with the horizontal line H parallel to the x-axis, as shown in FIG. 7B . As described above, it may have a second linear pattern L2 and/or a second grid L2′ forming an angle of +30° with the horizontal line H parallel to the x-axis. Each of the pitches P1, P2, and P3 are all the same, so that the magnitudes of the respective lattice vectors V1, V2, and V3 are the same. Since the directions of the grating vectors V1, V2, and V3 are perpendicular to the extending directions of the respective linear gratings, linear patterns, and gratings, the grating vector V1 of the linear grating 121 of the first diffractive optical element 120 is The direction is parallel to the x-axis direction, and the grating vector V2 direction of the first linear pattern L1 and/or the first grating L1' of the second diffractive optical element 130 is -120 with respect to the x-axis direction. ˚, the direction of the grating vector V3 of the second linear pattern L2 and/or the second grating L2' of the second diffractive optical element 130 is +120˚ with respect to the x-axis direction. can achieve Accordingly, the linear grating 121 of the first diffractive optical element 120, the first linear pattern L1 and the second linear pattern L2 of the second diffractive optical element 130, respectively, grating vectors V1, V2, V3) forms an angle of 60° with each other, so that the sum of the respective lattice vectors V1, V2, and V3 has a magnitude of 0. In addition, the linear grating 121 of the first diffractive optical element 120, the first grating L1' and the second grating L2' of the second diffractive optical element 130, respectively, grating vectors V1, V2, V3) forms an angle of 60° with each other, so that the sum of the respective lattice vectors V1, V2, and V3 has a magnitude of 0.

Meanwhile, in the region where the second diffractive optical element 120 is disposed, since the diffracted lights are output through the light guide unit 110 , the amount of output light is the region where the second diffractive optical element 120 is disposed. It is necessary to determine the shape of a two-dimensional pattern that can be uniformly induced across the

9A to 9K are diagrams illustrating the uniformity of light quantity distribution based on simulation results of light output according to the horizontal and vertical lengths and protrusion heights of a two-dimensional pattern in a predetermined region of the second diffractive optical element.

The uniformity of the light quantity distribution may be defined by Equation 2 below.

[Equation 2]

U = 1 - ((Imax - Imin) / (Imax + Imin))

Here, U is the uniformity of the light quantity distribution in the predetermined area, Imax is the highest value per unit area in the predetermined area, and Imin is the lowest light quantity per unit area in the predetermined area. The unit of I is (V/m)2.

The horizontal length Lx of the two-dimensional pattern 131 is a length in a direction close to perpendicular to the extension direction of the linear grating 121 provided in the first diffractive optical element 120 , and the vertical length of the two-dimensional pattern 131 . (Ly) denotes a length in a direction close to parallel to the extension direction of the linear grating 121 included in the first diffractive optical element 120 . Here, the meaning of being substantially perpendicular or parallel to the predetermined direction means substantially perpendicular or parallel to the predetermined direction, preferably forming an angle of 20 degrees or less with the predetermined direction, more preferably with the predetermined direction It means forming an angle of 5° or less.

FIG. 9A shows the uniformity of the light quantity distribution when the protrusion height of the two-dimensional pattern 131 is 40 nm. From FIG. 9B , the protrusion height of the two-dimensional pattern 131 is increased by 5 nm, and FIG. 9K shows the two-dimensional pattern 131 ) shows the uniformity of light quantity distribution when the protrusion height is 90 nm.

The wavelength of the light used in this simulation is 532 nm, and the pitch of the linear grating, the linear pattern and/or the gratings is 365 nm.

In general, when the vertical length (Ly) of the two-dimensional pattern 131 is longer than the horizontal length (Lx) and when the vertical length (Ly) and the horizontal length (Lx) are the same, the uniformity of the light quantity distribution is close to zero. seemed

When the horizontal length (Lx) of the two-dimensional pattern 131 is longer than the vertical length (Ly), the uniformity of the light quantity distribution is formed to be higher than other shapes, and depending on the degree of the horizontal length (Lx) and the vertical length (Ly) Although the uniformity of the light quantity distribution showed deviation, when the horizontal length (Lx) was 420 nm, the uniformity of the light quantity distribution was generally higher than that of other cases.

When the protrusion height of the two-dimensional pattern 131 is 40 nm, the uniformity of the light quantity distribution converges to 0 regardless of the horizontal length (Lx) and the vertical length (Ly), so that the protrusion height of the two-dimensional pattern 131 is higher than a predetermined height It could be deduced that it should be secured.

Looking at the results shown in FIGS. 9A to 9K , when the protrusion height of the two-dimensional pattern 131 is 45 to 60 nm, the vertical length (Ly) of the two-dimensional pattern 131 in which the uniformity of the light quantity distribution is at least 0.4. And it is confirmed that a plurality of combinations of the horizontal length (Lx) are derived. When the uniformity of the light quantity distribution is the same, the protrusion height of the two-dimensional pattern is generally proportional to the wavelength of the used light.

Since the wavelength of the light used in this simulation is 532 nm, it is preferable that the protrusion height of the two-dimensional pattern is 0.084 to 0.113 times the wavelength of the used light in order to show the uniformity of the light quantity distribution at a level of 0.4 or more.

And looking at the results shown in FIGS. 9A to 9K, when the vertical length (Ly) of the two-dimensional pattern 131 is 189 nm to 336 nm, the uniformity of the light distribution shows a level of 0.4 or higher of the two-dimensional pattern 131. It is confirmed that a plurality of combinations of the vertical length Ly and the horizontal length Lx are derived.

Since the pitch of the linear grating, the linear pattern, and/or the gratings used in this simulation is 365 nm, the vertical length (Ly) of the two-dimensional pattern is the linear grating, the linear pattern and/or It is preferably 0.50 to 0.921 times the pitch of the gratings.

And looking at the results shown in FIGS. 9A to 9K, when the horizontal length (Lx) of the two-dimensional pattern 131 is 420 nm to 483 nm, the uniformity of the light quantity distribution is at least 0.4 of the two-dimensional pattern 131. It is confirmed that a plurality of combinations of the vertical length Ly and the horizontal length Lx are derived.

Since the pitch of the linear grating, the linear pattern, and/or the gratings used in this simulation is 365 nm, the horizontal length (Lx) of the two-dimensional pattern is the linear grating, the linear pattern and/or It is preferably 0.150 to 1.324 times the pitch of the gratings.

Meanwhile, in FIG. 9C , the protrusion height of the two-dimensional pattern 131 is 50 nm, and the horizontal length (Lx) portion of the two-dimensional pattern extends in the linear grating 121 provided in the first diffractive optical element 120 . It shows the uniformity of the light quantity distribution when forming 90 °, and FIG. 9L shows the horizontal length (Lx) portion of the two-dimensional pattern compared to FIG. 9C of the linear grating 121 provided by the first diffractive optical element 120 It shows the uniformity of the light quantity distribution when it is rotated by 10° counterclockwise based on the direction perpendicular to the extension direction, and FIG. 9M shows that the horizontal length (Lx) part of the two-dimensional pattern compared to FIG. (120) shows the uniformity of the light quantity distribution when the linear grating 121 is rotated by 18° in a counterclockwise direction based on a direction perpendicular to the extension direction, and FIG. 9N is a two-dimensional pattern compared to FIG. 9C Showing the uniformity of the light quantity distribution when the horizontal length (Lx) part is rotated by 20° counterclockwise based on the direction perpendicular to the extension direction of the linear grating 121 provided in the first diffractive optical element 120 will be.

9C and 9L to 9M, the horizontal length (Lx) portion of the two-dimensional pattern is perpendicular to the extending direction of the linear grating 121 provided in the first diffractive optical element 120, or the horizontal length of the two-dimensional pattern When the length (Lx) part is rotated by less than 20° in a direction perpendicular to the extension direction of the linear grating 121 provided in the first diffractive optical element 120, the uniformity of the light quantity distribution exceeds 0. can be

In summary, in order to uniformly output light throughout the area in which the second diffractive optical element 130 is disposed, the horizontal cross section of the two-dimensional pattern 131 has an elliptical shape, and the long axis of the elliptical shape includes the first diffractive optical element 120 . It is preferable to form an angle of less than 20 ° with the direction perpendicular to the extension direction of the linear grating 121 .

A display apparatus (not shown) according to another aspect of the present invention may include a light source (not shown) for outputting image light forming an image, and the diffractive light guide plate 100 according to an aspect of the present invention. The image light output from the light source is input and diffracted to the first diffraction optical element 120 , and is coupled to the first grating L1 ′ and the second grating L2 ′ of the second diffraction optical element 130 , The first grating L1' and the second grating L2' are coupled to diffract the received light to expand one-dimensionally, and the one-dimensionally expanded light is a different type of grating L2' and L1'. may be coupled to and output from the light guide unit 110 by diffraction. Light received from the first diffraction optical element 120 by each of the first grating L1 ′ and the second grating L2 ′ constituted by a two-dimensional pattern disposed over the entire region of the second diffraction optical element 120 . It expands and outputs the expanded image light, so it is possible to form a large viewing angle and also form a wide i-motion box, which has the advantage of being able to respond widely to the pupils of users with various body conditions.

10A is an image obtained by capturing light output from a second diffractive optical element of an embodiment of a diffractive light guide plate according to an aspect of the present invention, and FIG. 10B is a second comparative example of a diffractive light guide plate having a circular horizontal cross-section of a two-dimensional pattern. It is an image obtained by capturing the light output from the diffractive optical element.

The light output from the second diffractive optical element of the comparative example is focused in the left-right direction rather than the up-down direction, and the light is output, whereas the light output from the second diffractive optical element of the embodiment of the present invention is also in the up-down direction including the left-right direction It can be seen that the light is distributed and uniformly output.

Although the present invention has been described with reference to the above-mentioned preferred embodiments, various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, it is intended that the appended claims cover such modifications and variations as long as they fall within the gist of the present invention.

100: diffraction light guide plate
110: optical guide part
120: first diffraction optical element
121: linear grid
130: second diffraction optical element
131: two-dimensional pattern
L1: first linear pattern
L2: second linear pattern
L1': first lattice
L2': second lattice

Claims (9)

a light guide unit for guiding light;
a first diffraction optical element having a linear grating repeatedly formed at a predetermined pitch so that light output from the light source is input and guided on the light guide unit to diffract the input light; and
A virtual first linear pattern that is disposed on one surface of the light guide part in a region distinct from the region in which the first diffractive optical element is disposed, and is repeatedly arranged at a predetermined pitch along the first direction, is different from the first direction A second diffractive optical element having a two-dimensional pattern provided in a region where a second virtual linear pattern repeatedly arranged at a predetermined pitch along a second direction intersects each other,
The horizontal cross-section of the two-dimensional pattern has an elliptical shape, and the angle formed by the long axis of the elliptical shape with the direction perpendicular to the extension direction of the linear grating provided in the first diffractive optical element is less than 20°,
The two-dimensional pattern is formed to protrude from one surface of the light guide part,
The protrusion height of the two-dimensional pattern is 0.084 to 0.113 times the wavelength of the light output from the light source, the diffraction light guide plate. delete delete The method of claim 1,
The long axis of the elliptical shape is 0.50 to 0.921 times the pitch of the linear grating and the linear pattern. According to claim 1,
The short axis of the elliptical shape is 0.084 to 0.113 times the pitch of the linear grating and the linear pattern. According to claim 1,
The linear grating and the linear pattern have a size inversely proportional to their pitch and a grating vector defined in a direction perpendicular to a direction in which the linear grating and the linear pattern extend,
The diffraction light guide plate, wherein the sum of the grating vectors of each of the linear grating of the first diffractive optical element, the first linear pattern of the second diffractive optical element, and the second linear pattern has a magnitude of zero. 7. The method of claim 6,
The linear grating of the first diffractive optical element, the grating vector of each of the first linear pattern and the second linear pattern of the second diffractive optical element have the same size. 7. The method of claim 6,
and a grating vector of each of the linear grating of the first diffractive optical element, the first linear pattern and the second linear pattern of the second diffractive optical element form an angle of 60° with each other. a light source for outputting image light forming an image; and
A display device comprising the diffractive light guide plate according to any one of claims 1 to 8.

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