Optical devices, modules and equipment

Abstract

Examples of this disclosure relate to optical devices, modules, and apparatuses. Examples of this disclosure relate to apparatuses including a light guide component. The light guide component includes at least: an inner coupling diffraction component configured to couple one or more input beams from within an optical engine to the light guide component; an extension component configured to extend one or more input beams; and an outer coupling diffraction component configured to externally couple one or more extended beams from the light guide component. The outer coupling diffraction component includes at least a first portion and at least a second portion, the first portion being configured to externally couple one or more extended beams with a first efficiency, and the second portion being configured to externally couple one or more extended beams with a second efficiency, wherein the second efficiency is lower than the first efficiency.

Description

Technical Field

[0001] Examples of this disclosure relate to optical devices, modules, and apparatuses. Some relate to optical devices, modules, and apparatuses for providing a more uniform exit pupil. Background Technology

[0002] Optical devices, such as exit pupil expanders, can be used in display systems and devices, such as near-eye displays, augmented and / or virtual reality headsets, and head-up displays. Summary of the Invention

[0003] Based on several, but not necessarily all, examples of the present disclosure, an apparatus is provided comprising: a light guide component including at least: an inner coupling diffraction component configured to couple one or more input beams from within an optical engine into the light guide component; an expansion component configured to expand one or more input beams; and an outer coupling diffraction component configured to externally couple one or more expanded beams from the light guide component; wherein the outer coupling diffraction component includes at least a first portion and at least a second portion, the first portion being configured to externally couple the expanded one or more beams with a first efficiency, and the second portion being configured to externally couple the expanded one or more beams with a second efficiency, wherein the second efficiency is lower than the first efficiency.

[0004] The second part of the externally coupled diffractive component can be configured to control the brightness of a portion of the light output provided by the device.

[0005] The first portion of the externally coupled diffraction component may include a diffraction grating having a first periodicity, and the second portion of the externally coupled diffraction component includes one or more sub-portions of the diffraction grating having the first periodicity, and one or more sub-portions not including the diffraction grating.

[0006] The sub-section without the diffraction grating can be located in the second part of the externally coupled diffraction component, between the sub-sections of the diffraction grating.

[0007] The periodicity of the sub-section within the second part of the externally coupled diffractive component can be configured to reduce the phase within the expanded beam.

[0008] The second part of the externally coupled diffraction component may include an absorption component configured to absorb at least some of the expanded beam.

[0009] The absorbent component may include an absorbent coating.

[0010] The second part of the externally coupled diffractive element may be located on at least one edge of the externally coupled diffractive element.

[0011] The size and shape of the externally coupled diffractive element are matched with the size and shape of the previous diffractive element so that the extreme rays of the extended element can be externally coupled by the externally coupled diffractive element.

[0012] The first part of the externally coupled diffractive element can be located at the edge furthest from the previous diffractive element, and the second part of the externally coupled diffractive element is located at the edge closest to the previous diffractive element.

[0013] A second portion of the externally coupled diffractive element may be provided across the externally coupled diffractive element, such that all light incident on the externally coupled diffractive element passes through the second portion of the externally coupled diffractive element.

[0014] Compared with the first part of the externally coupled diffractive component, the second part of the externally coupled diffractive component can be configured to have at least one of the following: different fill factors of the diffraction grating, different diffraction grating depths, different grating profiles, and different refractive index profiles.

[0015] The device may include a first light guide component and a second light guide component; wherein the second light guide component is provided to cover the first light guide component; and wherein the externally coupled diffractive component of the first light guide component includes an alternating sequence of diffractive and non-diffractive portions, and the externally coupled diffractive component of the second light guide component includes a corresponding alternating sequence of diffractive and non-diffractive portions, which are configured to reduce interference between light externally coupled from different externally coupled diffractive components.

[0016] An externally coupled diffractive component of the second light guide component may be provided, which covers the sequence of the externally coupled diffractive component of the second light guide component and the diffractive and non-diffractive portions, and the externally coupled diffractive component of the second light guide component is configured such that the non-diffractive portion of the externally coupled diffractive component of the second light guide component covers the diffractive portion of the externally coupled diffractive component of the first light guide component, and the diffractive portion of the externally coupled diffractive component of the second light guide component covers the non-diffractive portion of the externally coupled diffractive component of the first light guide component.

[0017] According to several, but not necessarily all, examples of this disclosure, an apparatus is provided comprising: a light guide, including at least: an inner coupling diffraction element configured to couple one or more input beams from within a light engine into the light guide; one or more expanders configured to expand the one or more input beams; and an outer coupling diffraction element configured to externally couple the expanded one or more beams from the light guide; wherein the outer coupling diffraction element includes at least a first portion and at least a second portion, the first portion being configured to externally couple the expanded one or more beams with a first efficiency, and the second portion being configured to externally couple the expanded one or more beams with a second efficiency, wherein the second efficiency is lower than the first efficiency. Attached Figure Description

[0018] Some examples will now be described with reference to the accompanying drawings, in which:

[0019] Figure 1 An example light guide component is shown;

[0020] Figure 2 An example light guide component is shown;

[0021] Figure 3 An example light guide component is shown;

[0022] Figure 4 An example light guide component is shown;

[0023] Figure 5 An example light guide component is shown;

[0024] Figure 6 An example light guide component is shown;

[0025] Figure 7 An example light guide component is shown;

[0026] Figures 8A to 8F Different examples of light guide components are shown;

[0027] Figure 9 An example light guide component is shown;

[0028] Figure 10 An example light guide component is shown;

[0029] Figure 11 An example light guide component is shown;

[0030] Figure 12 An example light guide component is shown;

[0031] Figure 13 An example light guide component is shown;

[0032] Figure 14 An example light guide component is shown;

[0033] Figure 15 An example light guide component is shown; and

[0034] Figure 16 An example light guide component is shown.

[0035] The accompanying drawings are not necessarily drawn to scale. For clarity and simplicity, some features and views in the drawings may be shown schematically or enlarged to scale. For example, the dimensions of some elements in the drawings may be enlarged relative to other elements to aid illustration. Similar reference numerals are used in the drawings to indicate similar features. For clarity, not all reference numerals may be shown in all drawings. Detailed Implementation

[0036] Figure 1An example light guide component 101 that can be used in the examples of this disclosure is shown. The light guide component 101 can be formed on a waveguide, an optical substrate, a transparent plate, or any other suitable material.

[0037] In this example, the light guide component 101 includes an exit pupil expander. The exit pupil expander is configured to increase the size of the exit pupil from the light engine or other optical arrangement. The light engine can be a display device, such as a light engine, projection engine, or image generation unit.

[0038] The light guide component 101 includes an inner coupling diffraction component 103, an extension component 105, and an outer coupling diffraction component 107 located on the surface or within the volume of the light guide component 101.

[0039] The internal coupling diffraction component 103 includes any component configured to internally couple one or more beams from the optical engine to the light guide component 101. The internal coupling diffraction component 103 is located within the light guide component 101 such that, in use, the internal coupling diffraction component 103 can be located adjacent to the optical engine.

[0040] The internally coupled beam propagates within the light guide component 101 via total internal reflection. The refractive index of the material used for the light guide component 101, the wavelength of the internally coupled beam, and the parameters of the internally coupled diffraction component 103 determine the total internal reflection angle.

[0041] The extension component 105 is located within the light guide component 101 to provide an internally coupled beam from the internally coupled diffraction component 103 to the extension component 105.

[0042] The expansion component 105 includes any component configured to expand the internally coupled beam in at least one dimension. The expansion component 105 may include a diffraction component, such as a diffraction grating or any other suitable component. In a diffraction grating, the internally coupled beam is split into two beams each time it interacts with the grating. The interaction can be, for example, internal reflection. The two split portions of the beam travel in different directions and continue to split, thereby expanding the exit pupil of the optical engine. Figure 1 In the example shown, the extension component 105 has a grating that extends the beam in the horizontal direction.

[0043] The external coupling diffraction component 107 is located within the light guide component 101 so that a horizontally extended beam of light is provided from the extension component 105 to the external coupling diffraction component 107.

[0044] The external coupling diffraction component 107 includes any component configured to externally couple a horizontally extended beam outside the light guide component. The external coupling diffraction component 107 can function similarly to the expansion component 105, such that the expanded beam is split into two beams each time it interacts with the diffraction grating. The external coupling diffraction component 107 can also be configured to expand the horizontally extended beam in a second dimension. Figure 1 In the example shown, the externally coupled diffractive element 107 includes horizontal grating lines that extend the horizontally extended beam in the vertical direction.

[0045] The light guide component 101 is configured such that the externally coupled extended beam can be seen by the user. The externally coupled extended beam provides a virtual image that can be observed by the user. Therefore, the externally coupled beam provides an extended exit pupil.

[0046] It should be understood that variations in the size, shape, position, and expansion direction of different diffraction components are examples, and other variations may be used in other examples of this disclosure. For example, expansion component 105 may expand the beam in a direction other than horizontal. As another example, externally coupled diffraction component 107 may expand the beam in a direction other than vertical. As a third example, the exit pupil of the beam coupled within the internally coupled diffraction component 103 is expanded in a first expansion dimension before being coupled into the light guide component 101 within the beam. In this example, no expansion component 105 is located within the light guide component 101. As a fourth example, the beam is coupled within the internally coupled component 103 to two different directions within the light guide component 101. In this example, there may be two separate expansion components 105 and a shared external coupling device 107 or two separate external coupling devices 107 for these two directions.

[0047] The diffraction components used for the inner coupling diffraction component 103, the extension component 105, and the outer coupling diffraction component 107 may include any component capable of being configured to diffract an input beam. The diffraction components may include any one or more of the following: diffraction optics, diffraction structures, diffraction gratings, holographic gratings, Bragg gratings, rulings, ridges, surface relief diffraction gratings, volumetric holograms, or any suitable optical component or feature having a periodic structure that splits and diffracts light into several beams traveling in different directions.

[0048] Figure 2 It shows in Figure 1 How the light guide component 101 shown can cause uneven brightness within the exit pupil.

[0049] exist Figure 2In this example, image 201 is provided to the inner coupling diffraction component 103. Image 201 in this example includes a single point 203 located at the center of image 201. This corresponds to a light beam projected from the light engine perpendicular to the light guide component 101.

[0050] Figure 2 The diagram illustrates how an inner-coupled beam, including image 201, is extended horizontally by extension member 105 and then vertically by outer-coupled diffraction member 107. This provides the outer-coupled beam with an extended horizontal exit pupil 205 and an extended vertical exit pupil 207.

[0051] An example exit pupil gate 209 is shown, which externally couples a light beam into an exit pupil. A representation of the light energy distribution of the externally coupled beam within an exit pupil 211 provided within this exit pupil gate 209 is also shown. The energy distribution of the exit pupil 211 is non-uniform. The energy distribution of the exit pupil 211 has a dark area towards the lower right corner of the exit pupil gate 209. This corresponds to the region in the externally coupled diffraction element 107 furthest from the extension element 105 and the internally coupled diffraction element 103. Therefore, the externally coupled light beam in this region of the exit pupil gate 209 further passes through the light guide element 101 and thus has a lower intensity. This results in uneven brightness within any image provided by these light guide elements 101.

[0052] It should be understood that Figure 2 This is a schematic diagram and not shown to scale. In the implementation of this disclosure, the inner coupling diffraction component 103 could potentially be much larger, resulting in a larger exit pupil with greater overlap. This can increase the uniformity of the outer coupling beam. Moreover, Figure 2 The images in the diagram already show light of a single wavelength. It should be understood that light of different wavelengths will be internally coupled to slightly different angles, which also partially increases beam uniformity.

[0053] Figure 3 This demonstrates how to at least partially correct uneven brightness within the exit pupil by providing different diffraction efficiencies within the light guide component 101.

[0054] exist Figure 3 In the example shown, the thickness of the extension member 105 increases along the horizontal length of the extender member. Curve 301 schematically illustrates how the thickness of the extension member 105 gradually increases along the length of the extension member 105 in the direction indicated by arrow 303. The thickness of the external coupling diffraction member 107 can also increase along the vertical length of the external coupling diffraction member 107 in the direction indicated by arrow 305.

[0055] Variations in thickness can provide variable diffraction efficiency in different sections of the light guide component 101. This helps reduce the non-uniformity of the exit pupil brightness. Figure 3 As shown, with Figure 2 Compared to the energy distribution of the exit pupil 211 provided by the light guide component 101, the energy distribution of the exit pupil 211 provided within the exit pupil gate 209 has a more uniform brightness.

[0056] It should be understood that other components for providing variable diffraction efficiency can be used in other examples. For example, different grating fill factors or grating profiles can be used for different portions of the diffraction component within the light guide component 101. Various combinations can also be used to provide more subtle variations in diffraction efficiency. For example, different thickness levels and grating fill factor levels can be used simultaneously in different portions of the diffraction component within the light guide component 101.

[0057] Figure 4 It shows Figure 1 Another example of how the light guide component 101 can cause uneven brightness within an image. This illustrates how the arrangement of diffractive elements within the light guide component 101 can produce a bright angle within the exit pupil.

[0058] Figure 4 Another example image 201 that can be provided to the internally coupled diffraction component 103 is shown. This example image 201 includes a single point 203 in the lower right corner of the image 201.

[0059] An example pupil gate 209 is shown in the lower right corner of the external coupling diffraction component 107. The energy distribution of the exit pupil 211 corresponding to this exit pupil gate 209 is also shown.

[0060] This shows a bright region 401 in the lower right corner of the energy distribution of the exit pupil 211. This is caused by the cross-section of the light guide component 101 shown within the dashed line 403. This section is provided between the extension component 105 and the external coupling diffraction component 107. This section does not include any diffraction grating, therefore, the intensity of light passing through this section is not reduced as much as that passing through the external coupling diffraction component 107. Therefore, this results in a bright lower corner in the energy distribution of the exit pupil 211 of the external coupling image 201.

[0061] Figure 5 A light guide component 101 according to an example of the present disclosure is shown. The light guide component 101 includes an inner coupling diffraction component 103, an extension component 105, and an outer coupling diffraction component 107.

[0062] exist Figure 5In the example shown, the externally coupled diffracting component 107 includes different portions 501, 503, which are configured to externally couple an extended beam with different efficiencies. The different portions 501, 503 are configured to provide more uniform brightness to the exit pupil of the light guide component 101. Specifically, the different portions 501, 503 can be configured to address issues such as... Figure 4 The problem with the bright bottom angle of the exit pupil shown.

[0063] The external coupling diffraction component 107 includes a first portion 501 configured to externally couple one or more extended beams at a first efficiency. The external coupling diffraction component 107 also includes one or more second portions 503 configured to externally couple one or more extended beams at a second efficiency different from the first efficiency.

[0064] The second efficiency is lower than the first efficiency, so that the second portion 503 of the external coupling diffraction component 107 externally couples the extended beam with a lower efficiency than the first portion 501 of the external coupling diffraction component 107. In some examples, the efficiency of beam external coupling can be varied across the various portions 501, 503, so that the external coupling efficiency varies across different regions. The total coupling efficiency from the second portion 503 will be lower than the total efficiency of the first portion 501.

[0065] One or more second portions 503 are located within the externally coupled diffractive element 107 to reduce the appearance of bright portions within the exit pupil. The one or more second portions 503 are thus configured to control the brightness of the light output provided by the device including the light guide element 101.

[0066] The relative positions and arrangement of the different portions 501, 503 within the externally coupled diffractive component 107 can depend on the configuration of the light guide component 101. For example, it can depend on the size, shape, and relative position of the individual diffractive components within the light guide component 101.

[0067] Figure 5 The externally coupled diffraction component 107 shown has a similar function to... Figures 1 to 4 The externally coupled diffracting component 107 shown has different sizes and shapes. Figures 1 to 4 In the middle, the external coupling diffraction component 107 has a rectangular shape, while... Figure 5 In the middle, the external coupling diffraction component 107 has a trapezoidal shape.

[0068] exist Figure 5In this example, the size and shape of the externally coupled diffracting component 107 are provided to match the size and shape of the preceding diffracting component, so that the extreme rays of the preceding diffracting component can be externally coupled by the externally coupled diffracting component 107. In this example, the preceding diffracting component is the extension component 105. In other examples, the preceding diffracting component may be the internally coupled diffracting component 103, or other intervening diffracting components may be included within the light guide component 101.

[0069] The extreme rays of the previous diffraction element are the rays diffracted at the edges of the previous diffraction element. Figure 4 In the example shown, extreme rays include rays passing through the portion represented by dashed line 403 that does not include any diffraction grating. However, in Figure 5 In the example, the external coupling diffraction component 107 extends far enough in the horizontal direction that these extreme rays are incident on the external coupling diffraction component 107.

[0070] In the examples of this disclosure, the dimensions of the externally coupled diffracting member 107 can be determined such that the edge of the externally coupled diffracting member 107 extends at least as far as the edge of the extension member 105, so that the extreme rays of the extension member 105 are incident on the externally coupled diffracting member 107. Figure 5 In the example, the side edge of the externally coupled diffractive component 107 matches the edge of the extension component 105. Other configurations may be used in other examples of this disclosure.

[0071] exist Figure 5 In the example, the longer base of the trapezoid is located closer to the extension member 105, while the shorter base of the trapezoid is located further away from the extension member 105.

[0072] exist Figure 5 In the example, the trapezoidal shape of the external coupling diffraction component 107 is formed by a rectangular first portion 501 and two triangular second portions 503. The two triangular second portions 503 are located on both sides of the rectangular first portion 501. The first portion 501 of the external coupling diffraction component 107 has a shape similar to... Figures 1 to 4 The standard externally coupled diffracting component 107 shown has the same size and shape, and the second portion 503 is provided as an additional portion on the side of the first portion 501. Other arrangements for the corresponding portions 501, 503 may be used in other examples of this disclosure. For example, in other examples, the second portion 503 may be provided only at one side edge of the rectangular first portion 501.

[0073] The second part 503 of the triangle has a lower diffraction efficiency than the first part 501. Different efficiencies of the different parts 501 and 503 of the externally coupled diffraction component 107 can be achieved in any suitable manner. For example, the diffraction grating in the second part 503 can have different diffraction grating fill factors, different diffraction grating depths, different grating profiles, or any other suitable different properties. Figure 6 An example of a light guide component is shown, in which different parts 501, 503 have different configurations for the diffraction grating.

[0074] In other examples, different efficiencies of different portions 501 and 503 of the externally coupled diffraction component 107 can be achieved by using an absorbing component to absorb some of the light in the second portion 503. Figure 7 An example light guide component 101 including an absorption component is shown.

[0075] Figure 6 An example of a light guide component 101 is shown, wherein different portions 501, 503 achieve different diffraction efficiencies through different diffraction grating configurations. In this example, the externally coupled diffraction component 107 is provided in a trapezoidal shape, wherein a triangular second portion 503 is provided at the edge of a rectangular first portion 501, as shown. Figure 5 As shown. Different shapes and configurations of the external coupling diffraction component 107 and its various parts can be used in other examples of this disclosure.

[0076] The first portion 501 of the externally coupled diffraction component 107 includes a diffraction grating having a first periodicity. The diffraction grating has the same periodicity across all the first portions 501 of the externally coupled diffraction component 107. The diffraction grating exists across all the first portions 501 of the externally coupled diffraction component 107.

[0077] The second portion 503 of the externally coupled diffraction component includes a diffraction grating, which does not exist across the entire area covered by the second portion. Figure 6 In the example shown, the second portion 503 includes sub-portions 601 and 603, where sub-portion 601 includes a diffraction grating and sub-portion 603 does not. The light beam is not externally coupled in sub-portion 603, which does not include the diffraction grating. This reduces the amount of externally coupled light in the second portion 503 compared to the amount of light externally coupled in the first portion 501.

[0078] exist Figure 6 In the example shown, each sub-section 601 comprising the diffraction grating is shown as including two slits. It should be understood that this is not shown to scale, and any number of grating lines or grating structures may be provided in each of these sub-sections.

[0079] The diffraction grating provided in subsection 601 of the second part 503 has the same periodicity as the diffraction grating provided in the first part.

[0080] Sub-portions 601 with diffraction gratings and sub-portions 603 without diffraction gratings are provided in alternating sub-portions within the second portion 503. Sub-portions 603 without diffraction gratings are located between sub-portions 601 including diffraction gratings. The periodicity of the sub-portions 601, 603 within the second portion 503 of the externally coupled diffraction component 107 can be selected to support the manufacturing process, thereby improving manufacturing efficiency. For example, the periodicity can be based on the stitching pattern generated by an electron beam lithography apparatus. The periodicity of the sub-portions 601, 603 within the second portion 503 of the externally coupled diffraction component 107 is configured to reduce the phase within the extended beam. For example, a non-repeating pattern is generated to minimize phase diffraction due to the periodicity of the sub-portions.

[0081] like Figure 6 As shown, extreme light rays from the edge of the extension member 105 are incident on the second portion 503 of the externally coupled diffraction member 107. This controls the brightness of these rays so that all the rays externally coupled within the exit pupil gate 209 have similar brightness levels.

[0082] When an image 201, including point 203 in the lower right corner, is provided to the light guide component 101, the second portion 503 of the externally coupled diffraction component 107 controls the brightness of the light beam that passes through the second portion 503 and is coupled externally to the exit pupil from the exit pupil gate 209. This makes the brightness of these beams after external coupling match the brightness of the beams in the remaining portion of the exit pupil. Figure 6 The energy distribution of the exit pupil 211 shown is uniform, thus exhibiting a high level of uniformity.

[0083] The diffraction efficiency of the second part 503 can be controlled by adjusting the relative proportion of the area of ​​the sub-part 601 including the diffraction grating to the area of ​​the sub-part 603 excluding the diffraction grating. If the proportion of the sub-part 601 with the diffraction grating is too high, this will reduce the brightness of the light beam in the energy distribution of the exit pupil 211. Conversely, if the proportion of the sub-part 601 with the diffraction grating is too low, this will not sufficiently reduce the brightness of the light beam. This will produce a brighter region in the lower right corner of the energy distribution of the exit pupil 211.

[0084] Figure 7 An example of a light guide component 101 is shown, wherein different portions 501, 503 achieve different beam brightness by using an absorption component in the second portion 503. In this example, the externally coupled diffracting component 107 is provided in a trapezoidal shape, and a triangular second portion 503 is provided at the edge of the rectangular first portion 501, as shown. Figure 5 and 6 As shown. Different shapes and configurations of the external coupling diffraction component 107 and its various parts can be used in other examples of this disclosure.

[0085] In this example, the absorbing component 701 includes an absorbing coating. The absorbing coating is provided in the second portion 503 of the external coupling diffraction component 107. The absorbing coating can be provided on the second portion 503 of the external coupling diffraction component 107 as a surface treatment.

[0086] In some examples, an absorbing coating may be provided to cover all of the second portion 503 of the externally coupled diffracting component 107. In other examples, the absorbing coating may be provided only on a portion of the second portion 503.

[0087] like Figure 7 As shown, extreme light rays from the edge of the extension member 105 are incident on the second portion 503 of the externally coupled diffractive member 107. The absorption member 701 controls the brightness of the beam so that the externally coupled beam within the exit pupil gate 209 is uniform or substantially uniform.

[0088] When an image 201, including point 203 in the lower right corner, is provided to the light guide component 101, the absorption component 701 in the second portion 503 of the externally coupled diffraction component 107 controls the brightness of the light beam passing through portion 503. This makes the brightness of these beams after external coupling towards the exit pupil within the exit pupil gate 209 match the brightness of the beams in the remaining portion of the exit pupil. Figure 7 The energy distribution of the exit pupil 211 shown is uniform, thus exhibiting a high level of uniformity.

[0089] The brightness of the light beam propagating through the second part 503 can be controlled by controlling the absorption component 701 used in the second part. For example, the brightness can be increased by providing a smaller amount of absorption component 701, or the brightness can be decreased by providing a larger amount of absorption component 701.

[0090] Figures 8A to 8F Examples of different arrangements of the light guide component 101 are shown, including different arrangements of diffraction elements and portions 501, 503 within the external coupling diffraction component 107. In these examples, the second portion 503 of the external coupling diffraction component 107 has a lower diffraction efficiency than the first portion 501. By using, as Figure 6 Different arrangements of the diffraction gratings shown, such as Figure 7 Different diffraction efficiencies can be achieved using the absorption coating 701 shown or any other suitable method.

[0091] exist Figure 8AIn the example, the light guide component 101 includes two extension components 105. An inner coupling diffraction component 103 is located between the two extension components 105 to provide a symmetrical arrangement.

[0092] exist Figure 8A In the example, the external coupling diffraction component 107 includes a trapezoidal shape. A first portion 501 of the external coupling diffraction component 107 includes a rectangular portion at the center of the external coupling diffraction component 107, and a second portion 503 of the external coupling diffraction component 107 is provided as two triangles on the sides of the rectangular first portion 501.

[0093] exist Figure 8B In this example, the light guide component 101 includes an inner coupling diffraction component 103 and an outer coupling diffraction component 107. In this example, the light beam is extended in a first direction before being provided to the light guide component 101. In this example, the inner coupling diffraction component 103 has an elongated shape and no additional extension component 105 is provided.

[0094] In this example, the inner coupling diffraction element 103 is a prior diffraction element for the outer coupling diffraction element 107.

[0095] The external coupling diffraction component 107 includes two second portions 503 configured to externally couple the extended beam at a lower efficiency level than the first portion 501 of the external coupling diffraction component 107. Figure 8B In the example, the second part 503 includes a triangular portion provided at the side edge of the trapezoidal external coupling diffraction member 107.

[0096] exist Figure 8C In the example, the inner coupling diffraction component 103, the extension component 105, and the outer coupling diffraction component 107 are provided in a horizontally extending order, such that the inner coupling diffraction component 103 is located to the left of the extension component 105, and the outer coupling diffraction component 107 is located to the right of the extension component 105.

[0097] exist Figure 8D In the example, an inner coupling diffraction component 103 is provided above the extension component 105, such that the inner coupling diffraction component 103, the extension component 105, and the outer coupling diffraction component 107 are provided in an L-shape.

[0098] exist Figure 8E In the example, the inner coupling diffraction component 103 and the extension component 105 are provided on top of the outer coupling diffraction component 107, such that the inner coupling diffraction component 103, the extension component 105 and the outer coupling diffraction component 107 are provided in an inverted L shape.

[0099] In each of the examples 8B to 8E, the externally coupled diffracting element 107 includes two second portions 503 configured to externally couple an extended beam at a lower efficiency level than the first portion 501 of the externally coupled diffracting element 107. In each of these examples, the second portion 503 includes a triangular portion provided at the side edges of the trapezoidal externally coupled diffracting element 107.

[0100] exist Figure 8F In the example shown, the light guide component 101 includes two inner coupling diffraction components 103, two extension components 105, and a central outer coupling diffraction component 107. The first inner coupling diffraction component 103 and the first extension component 105 are provided above the shared outer coupling diffraction component 107, such that the first inner coupling diffraction component 103, the first extension component 105, and the shared outer coupling diffraction component 107 are provided in an inverted L-shape. The second inner coupling diffraction component 103 and the second extension component 105 are provided below the shared outer coupling diffraction component 107, such that the shared outer coupling diffraction component 107, the extender component 103, and the inner coupling component 103 are provided in an L-shape.

[0101] The shared external coupling diffraction component 107 includes a rectangular first portion 501 provided at the center of the external coupling diffraction component 107. A second portion 503 is provided on the side of the rectangular first portion 501. In this example, each second portion has a shape formed by two right-angled triangles connected at the vertices of a triangle. Other shapes of portions 501, 503 of the external coupling diffraction component 107 may be used in other examples of this disclosure.

[0102] Figure 9 Another example of the light guide component 101 is shown. In this example, variations in the thickness of the extension component 105 and the external coupling diffraction component 107 can lead to uneven brightness in the exit pupil.

[0103] exist Figure 9 In the example shown, the thickness of the extension member 105 increases along its horizontal length. The extension member 105 is shallowest closest to the inner coupling diffraction member 103 and deepest furthest away from it. Curve 901 schematically illustrates how the thickness of the extension member 105 increases along its length. In this example, the thickness of the extension member 105 increases in stepwise increments. The target change in depth could be a smooth curve; however, due to manufacturing tolerances, the actual change in thickness can be provided in stepwise increments.

[0104] The thickness of the external coupling diffraction component 107 can also increase along its vertical length. The shallowest part of the external coupling diffraction component 107 is closest to the extension component 105, and the deepest part is furthest away from the extension component 105. The thickness of the external coupling diffraction component 107 can also be gradually increased.

[0105] The gradual change in thickness of the extension component 105 and the external coupling diffraction component 107 can lead to uneven brightness in the exit pupil of the light guide component 101. Figure 9 In this example, image 201 is provided to the inner coupling diffraction component 103. Image 201 in this example includes a single point 203 at the center of image 201.

[0106] An example exit pupil gate 209 is shown, and a representation of the energy distribution of the exit pupil 211 provided within the exit pupil gate 209 is shown. The energy distribution of the exit pupil 211 is non-uniform and has multiple dark areas that increase in a stepped manner corresponding to the depths of the extension member 105 and the external coupling diffraction member 107.

[0107] Figure 10 Another example light guide component 101 is shown, which is configured to correct brightness inhomogeneities caused by gradual changes in the thickness of the extension component 105 and the externally coupled diffractive component 107.

[0108] In this example, the externally coupled diffractive component 107 includes a first portion 501 and a second portion 503, wherein the second portion 503 has a lower diffraction efficiency to address the thickness variations of the various components of the light guide component 101.

[0109] In this example, the external coupling diffraction component 107 has a rectangular shape. The external coupling diffraction component is positioned such that the length of the rectangle extends parallel to or substantially parallel to the length of the extension component 105.

[0110] In this example, the first portion 501 of the externally coupled diffractive element 107, having higher diffraction efficiency, is provided as a rectangular portion. The first portion 501 is provided in the region of the externally coupled diffractive element 107 furthest from the extension element 105. The second portion 503 of the externally coupled diffractive element 107, having lower diffraction efficiency, is also provided as a rectangular portion. This second portion 503 is provided in the region of the externally coupled diffractive element 107 closest to the extension element 105.

[0111] exist Figure 10In the example shown, a second portion 503 of the external coupling diffraction member 107 is provided across the external coupling diffraction member 107 such that all light incident on the external coupling diffraction member 107 passes through the second portion 503. The second portion 503 extends along the length of the external coupling diffraction member 107. The second portion 503 may extend along the entire length of the external coupling diffraction member 107.

[0112] Figure 11 Another example light guide component 101 is shown, which is configured to correct brightness inhomogeneities caused by gradual changes in the thickness of the extension component 105 and the externally coupled diffractive component 107.

[0113] In this example, the externally coupled diffractive component 107 also includes a first portion 501 and a second portion 503, wherein the second portion 503 has a lower diffraction efficiency to address the thickness variations of the various components of the light guide component 101.

[0114] In this example, the external coupling diffraction component 107 has a trapezoidal shape. The external coupling diffraction component is positioned such that the base of the trapezoid is parallel to or substantially parallel to the length extension of the extension component 105.

[0115] In this example, the first portion 501 of the externally coupled diffractive element 107, which has higher diffraction efficiency, is provided as a trapezoidal portion. The first portion 501 is provided in the region of the externally coupled diffractive element 107 furthest from the extension element 105. The second portion 503 of the externally coupled diffractive element 107, which has lower diffraction efficiency, is also provided as a trapezoidal portion. This second portion 503 is provided in the region of the externally coupled diffractive element 107 closest to the extension element 105.

[0116] The dimensions of the external coupling diffraction element 107 are determined such that the edge of the external coupling diffraction element 107 extends at least to the edge of the extension element 105. This allows the extreme rays from the extension element 105 to be incident on the external coupling diffraction element 107. Figure 11 In the example, the side edge of the externally coupled diffractive component 107 matches the edge of the extension component 105. Other configurations may be used in other examples of this disclosure.

[0117] exist Figure 11 In the example shown, a second portion 503 of the external coupling diffraction member 107 is provided across the external coupling diffraction member 107 such that all light incident on the external coupling diffraction member 107 passes through the second portion 503. The second portion 503 extends along the length of the external coupling diffraction member 107. The second portion 503 may extend along the entire length of the external coupling diffraction member 107.

[0118] Figure 10 and 11The different diffraction efficiencies shown in section 503 can be achieved using any suitable method. In some examples, different diffraction efficiencies can be achieved by providing different fill factors, different diffraction grating depths, different grating profiles, different refractive index profiles, or any other suitable variation of the diffraction grating. A number of different methods can be used together to control the diffraction efficiency to obtain a uniform exit pupil. In some cases, not all of these methods are available due to, for example, manufacturing limitations. Figure 12 and 13 Examples of different configurations of the diffraction grating within the second portion 503 of the externally coupled diffraction component 107 are shown. These configurations illustrate how they control diffraction efficiency to achieve better uniformity of the exit pupil. These examples can also be combined with other methods of controlling diffraction efficiency.

[0119] Figure 12 Another example light guide component 101 is shown. Figure 12 In the example shown, the external coupling diffraction component 107 has a rectangular shape. The external coupling diffraction component is positioned such that the length of the rectangle extends parallel to or substantially parallel to the length of the extension component 105.

[0120] In this example, the first portion 501 of the externally coupled diffractive component 107, which has higher diffraction efficiency, is provided as a rectangular portion, while the second portion 503 of the externally coupled diffractive component 107, which has lower diffraction efficiency, is also provided as a rectangular portion, and their arrangement is similar to... Figure 10 The layout shown is similar.

[0121] exist Figure 12 In the example shown, the second portion 503 of the externally coupled diffraction component 107 includes a non-uniform diffraction grating over all areas covered by the second portion 503. Figure 12 In the example shown, the second part 503 includes sub-parts 601 and 603, sub-part 601 including a diffraction grating, and sub-part 603 not including a diffraction grating. The size and position of each sub-part 601, 603 are positioned to control the brightness of the beam, thereby providing a uniform brightness level on the exit pupil.

[0122] The diffraction grating provided in subsection 601 of the second section 503 has the same periodicity as the diffraction grating provided in the first section 501. The diffraction grating may be uniform throughout the first section 501.

[0123] Sub-sections 601 with diffraction gratings and sub-sections 603 without diffraction gratings are provided alternately in the second section 503. Sub-sections 603 without diffraction gratings are located between sub-sections 601 including diffraction gratings. The periodicity of sub-sections 601, 603 within the second section 503 of the externally coupled diffraction component 107 is configured to reduce the phase within the extended beam.

[0124] exist Figure 12 In the example shown, sub-parts 601 and 603 extend over the entire length of the rectangle forming the external coupling diffraction member 107. Sub-parts 601 and 603 thus comprise elongated rectangular shapes extending along the length of the external coupling diffraction member 107. In this example, sub-part 601, which includes a diffraction grating portion, extends along the entire length of the external coupling diffraction member 107, while sub-part 603, which does not include any diffraction grating, also extends along the entire length of the external coupling diffraction member 107.

[0125] exist Figure 12 In the example shown, the sub-section 601 including the diffraction grating is shown as comprising two or three slits. It should be understood that this is not shown to scale, and any number of diffraction grating lines or diffraction structures can be provided in each of these sub-sections 601. It should be understood that different numbers of diffraction grating lines or diffraction structures can be provided in different sub-sections 601.

[0126] When an image 201, including the center point 203, is provided to the light guide component 101, the second portion 503 of the externally coupled diffraction component 107 controls the brightness of the light beam passing through portion 503. This matches the brightness of these beams after external coupling with the brightness of the beam in the remaining portion of the exit pupil. Figure 12 The energy distribution of the exit pupil 211 shown is uniform, thus exhibiting a high level of uniformity.

[0127] Figure 13 Another example light guide component 101 is shown, which is configured to correct for brightness variations caused by different thicknesses of the components of the light guide component 101. Figure 13 In the example shown, the external coupling diffraction component 107 has a rectangular shape. The external coupling diffraction component is positioned such that the length of the rectangle extends parallel to or substantially parallel to the length of the extension component 105.

[0128] In this example, the first portion 501 of the externally coupled diffractive component 107, which has higher diffraction efficiency, is provided as a rectangular portion, while the second portion 503 of the externally coupled diffractive component 107, which has lower diffraction efficiency, is also provided as a rectangular portion, and their arrangement is similar to... Figure 10 The layout shown is similar.

[0129] exist Figure 13In the example shown, the second portion 503 of the externally coupled diffraction component 107 includes a non-uniform diffraction grating over all areas covered by the second portion 503. Figure 13 In the example shown, the second part 503 includes sub-parts 601 and 603, where sub-part 601 includes a diffraction grating and sub-part 603 does not. The size and position of each sub-part 601, 603 are positioned to control the brightness of the light, thereby providing a uniform brightness level on the exit pupil.

[0130] The diffraction grating provided in the sub-section 601 of the second section 503 has the same periodicity as the diffraction grating provided in the first section 501.

[0131] exist Figure 13 In the example, a sub-portion 601 including a diffraction grating and a sub-portion 603 excluding a diffraction grating are provided alternately along the length of the externally coupled diffraction member 107. The sub-portion 601 including the diffraction grating and the sub-portion 603 excluding the diffraction grating are provided alternately along the length of the externally coupled diffraction member 107. The sub-portion 601 including the diffraction grating has a tapered shape, wherein the narrowest end of this shape is closest to the extension member 105, and the widest end is adjacent to the first portion of the externally coupled diffraction member 107. The sub-portion 603 excluding the diffraction grating has a tapered shape that is inverted compared to the tapered shape of the sub-portion 601 including the diffraction grating. Therefore, the narrowest end of the sub-portion 603 excluding the diffraction grating is provided at the end adjacent to the first portion 501 of the externally coupled diffraction member 107, while the widest end is provided closest to the extension member 105.

[0132] When an image 201, including the center point 203, is provided to the light guide component 101, the second portion 503 of the externally coupled diffraction component 107 controls the brightness of the light beam passing through portion 503. This matches the brightness of these beams after external coupling with the brightness of the beam in the remaining portion of the exit pupil. Figure 13 The energy distribution of the exit pupil 211 shown is uniform, thus exhibiting a high level of uniformity.

[0133] Figure 14 An example device 1401 is shown, including a first light guide component 101A and a second light guide component 101B. In device 1401, the second light guide component 101B is provided to cover the first light guide component 101A. Figure 14 The first light guide component 101A and the second light guide component 101B are also shown separately to illustrate the assembly of each light guide component 101A, 101B.

[0134] Each of the first light guide component 101A and the second light guide component 101B includes inner coupling diffraction components 103A and 103B, extension components 105A and 105B, and outer coupling diffraction components 107A and 107B.

[0135] exist Figure 14 In the example shown, the inner coupling diffraction components 103A, 103B, the extension components 105A, 105B, and the outer coupling diffraction components 107A, 107B have the same size and shape in each of the different light guide components 101A, 101B, so that when the second light guide component 101B is provided to cover the first light guide component 101A, the corresponding components of the different light guide components 101A, 101B match each other.

[0136] Externally coupled diffractive elements 107A and 107B are configured to reduce interference between them when light externally coupled from different light guide elements 101A and 101B stacks on top of each other. Figure 14 In the example, the externally coupled diffracting component 107A of the first light guide component 101A includes an alternating sequence of a first portion 501 and a second portion 503. The first portion 501 may be a diffracting portion, and the second portion 503 may be a non-diffracting portion, in order to reduce interference from externally coupled light from different light guide components 101A and 101B.

[0137] exist Figure 14 In the example shown, the first portion 501 and the second portion 503 form elongated portions 501, 503 extending away from the extension member 105. Other configurations may be used in other examples.

[0138] The first portion 501 and the second portion 503 of the externally coupled diffractive component 107B of the second light guide component 101B are sequentially configured such that when the second light guide component 101B is provided to cover the first light guide component 101A, the first portion 501 of the second light guide component 101B covers the second portion 503 of the first light guide component 101A. Similarly, the second portion 503 of the second light guide component 101B covers the first portion 501 of the first light guide component 101A.

[0139] The alternating sequence of the first portion 501 and the second portion 503 extends across all regions of the externally coupled diffractive elements 107A and 107B. The first portion 501 and the second portion 503 are configured such that approximately half of the externally coupled diffractive elements 107A and 107B includes diffractive portions, and approximately half of the externally coupled diffractive elements 107A and 107B includes non-diffractive portions.

[0140] exist Figure 14In the example shown, the first portion 501 has a similar width to the second portion 503. Other configurations of the corresponding portions 501 and 503 can be used in other examples of this disclosure.

[0141] exist Figure 14 In the example shown, the second light guide component 101B has the same configuration as the first light guide component 101A, such that when they are in a stacked configuration, each component of the second light guide component 101B covers the corresponding component of the first light guide component 101A. Figure 15 Another example is shown, in which the second light guide component 101B has a different configuration than the first light guide component 101A.

[0142] exist Figure 15 In the example, the second light guide component 101B is configured such that the extension component 105B is provided below the inner coupling diffraction component 103B rather than on the side of the inner coupling diffraction component. When the second light guide component 101B is positioned to overlap with the first light guide component 101A, the corresponding extension components 105A and 105B do not overlap; however, the corresponding inner coupling diffraction components 103A and 103B will still overlap each other, and the outer coupling diffraction components 107A and 107B will still overlap each other.

[0143] The first portion 501 and the second portion 503 of the first externally coupled diffractive component 107A form elongated portions 501 and 503, which are similar to Figure 14 The example shown extends away from the extension component 105. However, in Figure 15 In the second externally coupled diffracting component 107B, the first portion 501 and the second portion 503 form elongated portions 501, 503 extending parallel to the extension component 105B. This ensures that when the second light guide component 101B is provided in the device 1501 covering the first light guide component 101A, the first portion 501 of the second light guide component 101B covers the second portion 503 of the first light guide component 101A. Similarly, the second portion 503 of the second light guide component 101B covers the first portion 501 of the first light guide component 101A.

[0144] exist Figure 14 and 15 In the example shown, the corresponding externally coupled diffractive elements 107A and 107B are configured such that they completely overlap each other. In some examples, there may only be partial overlap between the corresponding externally coupled diffractive elements 107A and 107B.

[0145] Figure 16 Another example device 1401 is shown, including a first light guide component 101A and a second light guide component 101B. Figure 16An example light guide component 101 is shown, which includes an inner coupling diffraction component 103, an extension component 105, and an outer coupling diffraction component 107. Two of these light guide components 101A and 101B can be stacked to form a shape such as... Figure 16 The device 1401 shown.

[0146] In this example, the externally coupled diffractive element 107 is also configured to reduce interference between light externally coupled from different light guide elements when different light guide elements are stacked on top of each other to form device 1401. Figure 16 In the example, the externally coupled diffractive component 107 also includes an alternating sequence of a first portion 501 and a second portion 503, wherein the first portion 501 may be a diffractive portion and the second portion 503 may be a non-diffractive portion.

[0147] exist Figure 16 In the example shown, the first portion 501 and the second portion 503 form elongated portions 501, 503 extending away from the extension member 105. Figure 16 In the example, the first part 501 is increased in size on the trans-external coupling diffraction component 107. Figure 16 In the example, the first portion 501 closest to the extension member 105 is smaller than the first portion 501 farther from the extension member 105. Figure 16 In the example, the second part 503 has a reduced size on the trans-external coupling diffraction component 107. Figure 16 In the example, the second portion 503 closest to the extension member 105 is larger than the second portion 503 farther away from the extension member 105.

[0148] When the first light guide component 101A and the second light guide component 101B are stacked, the second light guide component 101B is configured as a mirror image of the first light guide component 101A, as if the first light guide component 101A has been reflected around the horizontal axis.

[0149] The dimensions and spacing of the first portion 501 and the second portion 503 of the externally coupled diffracting component 107B of the second light guide component 101B are configured such that when the second light guide component 101B is provided to cover the first light guide component 101A, the first portion 501 of the second light guide component 101B covers the second portion 503 of the first light guide component 101A. Similarly, the second portion 503 of the second light guide component 101B covers the first portion 501 of the first light guide component 101A.

[0150] Therefore, examples of the present invention provide various light guide components that can be configured to provide more uniform brightness in the exit pupil and thus provide improved image quality.

[0151] The device including the light guide component 101 as described above can be included in a module, device, display, stereoscopic display, autostereoscopic display, head-up display, display unit of a vehicle and / or vehicle or any other suitable entity.

[0152] The term "includes" is used herein in a sense of inclusion rather than exclusivity. That is, any reference to X that includes Y implies that X may contain only one Y or may contain more than one Y. If the intention is to use "includes" with an exclusive meaning, it is made clear in the context by referring to "includes only one" or by using "comprises".

[0153] Various examples are referenced in this specification. Descriptions of features or functions relating to examples indicate which features or functions exist in that example. Whether explicitly stated or not, the use of the terms “example,” “for example,” “can,” or “may” throughout the text indicates that such features or functions exist in at least the described example, whether or not they are described as examples, and that they may, but not necessarily, exist in some or all of the other examples. Therefore, “example,” “for example,” “can,” or “may” refers to a specific instance of a class of examples. An instance’s property may be a property of only that instance, or a property of the class, or a property of a subclass of a class that includes some, but not all, instances of that class. Therefore, it is implicitly disclosed that features described with reference to one example, and not to another, may be used in those other examples as part of a combination of works where possible, but are not necessarily required to be used in those other examples.

[0154] Although examples have been described with reference to various examples in the preceding paragraphs, it should be understood that modifications may be made to the given examples without departing from the scope of the claims.

[0155] The features described above can be used in combinations other than those explicitly described above.

[0156] Although the functions have been described with reference to certain features, these functions can be performed by other features regardless of whether they are described or not.

[0157] Although features have been described with reference to some examples, these features may exist in other examples, whether or not they are described.

[0158] The terms “a” or “the” are used herein in an inclusive rather than exclusive sense. That is, unless the context explicitly indicates otherwise, any reference to X that contains one Y implies that X may contain only one Y or may contain more than one Y. If the intention is to use “a” or “the” with an exclusive meaning, it will be made clear in the context. In some cases, the use of “at least one” or “one or more” may be used to emphasize the inclusive meaning, but the omission of these terms should not be construed as implying any exclusive meaning.

[0159] The presence of a feature (or combination of features) in a claim is a reference to that feature or feature (combination of features) itself, as well as to features that achieve substantially the same technical effect (equivalent features). Equivalent features include, for example, variations of features, and achieve substantially the same result in substantially the same manner. Equivalent features, for example, include features that perform substantially the same function in substantially the same manner to achieve substantially the same result.

[0160] In this specification, various examples using adjectives or adjective phrases have been referenced to describe the characteristics of the examples. Such descriptions of characteristics associated with examples indicate that the characteristic exists exactly as described in some examples, and substantially as described in others.

[0161] Although efforts have been made in the foregoing specification to draw attention to those features that are considered important, it should be understood that, whether or not they are emphasized, the applicant may seek protection by means of the claims for any patentable feature or combination of features mentioned above and / or shown in the drawings.

Claims

1. A device for guiding light, comprising: A light guide component, comprising at least: an inner coupling diffraction component configured to couple one or more input beams from within a light engine into the light guide component; an extension component configured to extend the one or more input beams; and an outer coupling diffraction component configured to externally couple the extended one or more beams from the light guide component. The externally coupled diffraction component includes at least a first portion and at least a second portion, the first portion being configured to externally couple the expanded one or more beams with a first efficiency, and the second portion being configured to externally couple the expanded one or more beams with a second efficiency lower than the first efficiency. The second portion of the externally coupled diffractive element includes an absorption element configured to absorb at least some of the expanded beam.

2. The apparatus of claim 1, wherein the second portion of the externally coupled diffracting component is configured to control the brightness of a portion of the light output provided by the apparatus.

3. The apparatus according to claim 1 or 2, wherein the absorbent component comprises an absorbent coating.

4. The apparatus of claim 3, wherein the absorbent coating is provided as a surface treatment.

5. The apparatus according to any one of claims 3 to 4, wherein the absorbing coating is provided to cover a portion of the second part of the externally coupled diffractive element.

6. The apparatus according to any one of claims 3 to 4, wherein the absorbing coating is provided to cover the entire second portion of the externally coupled diffracting component.

7. The apparatus of claim 1 or 2, wherein the brightness of the expanded one or more light beams can be controlled by controlling the absorption element used in the second portion of the externally coupled diffractive element.

8. The apparatus of claim 1 or 2, wherein the brightness of the extended one or more light beams can be increased by providing a smaller amount of absorbing material.

9. The apparatus of claim 1 or 2, wherein the brightness of the extended one or more light beams can be reduced by providing a greater number of absorbing elements.

10. The apparatus according to any one of the preceding claims, wherein the second portion of the external coupling diffraction member is positioned on at least one edge of the external coupling diffraction member.

11. The apparatus of claim 1 or 2, wherein the size and shape of the externally coupled diffractive element are configured to match the size and shape of the previous diffractive element so that the extreme rays of the extended element can be externally coupled by the externally coupled diffractive element.

12. The apparatus of claim 1 or 2, wherein the first portion of the externally coupled diffractive element is located at the edge furthest from the previous diffractive element, and the second portion of the externally coupled diffractive element is located at the edge closest to the previous diffractive element.

13. The apparatus of claim 1 or 2, wherein the second portion of the external coupling diffraction member is provided across the external coupling diffraction member such that all light incident on the external coupling diffraction member passes through the second portion of the external coupling diffraction member.

14. The apparatus according to claim 1 or 2, wherein, Compared with the first portion of the externally coupled diffractive component, the second portion of the externally coupled diffractive component is configured to have at least one of the following: different fill factors of the diffraction grating, different diffraction grating depths, different grating profiles, and different refractive index profiles.

15. The apparatus according to claim 1 or 2, wherein the apparatus comprises a first light guide component and a second light guide component; The second light guide component is provided to cover the first light guide component; and The externally coupled diffractive component of the first light guide component includes an alternating sequence of diffractive and non-diffractive portions, and the externally coupled diffractive component of the second light guide component includes a corresponding alternating sequence of diffractive and non-diffractive portions, the corresponding alternating sequence being configured to reduce interference between light externally coupled from different externally coupled diffractive components.

16. The apparatus according to claim 15, wherein, The externally coupled diffractive component of the second light guide component is provided to cover the sequence of the externally coupled diffractive component of the second light guide component and the diffractive portion and the non-diffractive portion, and the externally coupled diffractive component of the second light guide component is configured such that: the non-diffractive segment of the externally coupled diffractive component of the second light guide component covers the diffractive portion of the externally coupled diffractive component of the first light guide component, and the diffractive portion of the externally coupled diffractive component of the second light guide component covers the non-diffractive portion of the externally coupled diffractive component of the first light guide component.

17. A display module, a display device, a display, a stereoscopic display, an autostereoscopic display, a head-up display, a display unit for a vehicle, and / or a vehicle, comprising the means according to any one of claims 1-16.

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