DISPLAY DEVICE

Abstract

Display device (10, 10', 20, 30), comprising: a light source (100) having a light-emitting surface (105); a light-transmitting layer (200) covering the light source (100); wherein the light-transmitting layer (200) has a light-exiting surface (205); a first metasurface (300) formed between the light-emitting surface (105) and the light-transmitting layer (200), wherein the first metasurface (300) has a plurality of first microstructures (350), and the first microstructures (350) are arranged parallel to the light-emitting surface (105) to form a plurality of circles, wherein the sizes of the cross sections of the first microstructure (350) parallel to the light-emitting surface (105) change such that they gradually decrease from the outer to the inner circles, wherein such a size change is repeated one or more times to arrange the plurality of circles of the first microstructures (350); and a second metasurface (400) formed on the light exit surface (205), wherein the second metasurface (400) has a plurality of second microstructures (450) and the shape of the cross section of the second microstructure (450) parallel to the light-emitting surface (105) has a short axis along a first direction (D1) that is parallel to the light-emitting surface (105), and a long axis along a second direction (D2) that is parallel to the light-emitting surface (105) and perpendicular to the first direction (D1), and wherein the light-emitting surface (105) is configured to emit light in the direction of the light-exit surface (205), the first metasurface (300) is configured to concentrate the light emitted by the light-emitting surface (105) relative to an axis of a third direction (D3) that is perpendicular to the light-emitting surface (105) on the cross-sectional plane along the first direction (D1), the light-exit surface (205) is configured to receive the light emitted by the light-emitting surface (105) and guided through the first metasurface (300), and the second metasurface (400) is configured to deflect the received light in a positive direction of the first direction (D1) and a negative direction of the first direction (D1) with respect to the axis of the third direction (D3).

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a display device. Specifically, the present invention relates to a display device provided with two metasurfaces on a light output path. STATE OF THE ART

[0002] With the proliferation and development of display devices, the demand for display devices that can be used for display from various viewing angles is also increasing. However, the light source generally arranged in the display device has a limited light emission angle or an excessively wide light emission angle. With the miniaturization of components within the display device and the corresponding subpixels, it is difficult to design and adjust the light source for displaying at different viewing angles. Furthermore, if displaying by wide-angle light emission for different viewing angles may cause undesirable optical loss or optical noise at unexpected viewing angles.To overcome the above technical problems and difficulties, it is therefore necessary to design a structure, apart from the light source, that can adjust and concentrate the light to a desired light exit viewing angle. In this context, US 10 896 994 B1 discloses a light-emitting diode with a hyperbolic metamaterial structure structured to provide an array of nanoantennas for apodizing the emitted beam. Furthermore, CN 1 08 061 936 A discloses an optical splitter comprising a first microstructure unit and a second microstructure unit, and an optical splitting method using the optical splitter. Further, CN 1 10 488 317 A discloses a lidar device with a metasurface including a plurality of beam steering cells arranged in the form of a two-dimensional array.Furthermore, US 2015 / 0 219 806 A1 discloses an optical device having a first metasurface and a second metasurface. US 2021 / 0 263 329 A1 also discloses a device that relies on patterned metasurfaces to reduce speckle when an object is illuminated with coherent light. Furthermore, CN 1 03 293 684 A discloses a 3D display device comprising a light conversion module for converting light into a plurality of light points. Furthermore, US 2017 / 0 287 151 A1 discloses a structured light generator comprising a light source and a first meta-optical device having a first metasurface with nanostructures. DISCLOSURE OF THE INVENTIONTechnical means for solving the problem

[0003] To solve the above problems, the present invention provides a display device comprising: A light source having a light-emitting surface; a light-transmitting layer covering the light source; wherein the light-transmitting layer has a light-exit surface; a first metasurface formed between the light-emitting surface and the light-transmitting layer, the first metasurface having a plurality of first microstructures, the first microstructures being arranged parallel to the light-emitting surface to form a plurality of circles, the sizes of the cross sections of the first microstructure parallel to the light-emitting surface changing so as to gradually decrease from the outer to the inner circles, such a change in size being repeated one or more times to arrange the plurality of circles of the first microstructures; and a second metasurface formed on the light-exit surface,wherein the second metasurface has a plurality of second microstructures, and the shape of the cross-section of the second microstructure parallel to the light-emitting surface has a short axis along a first direction that is parallel to the light-emitting surface, and a long axis along a second direction that is parallel to the light-emitting surface and perpendicular to the first direction, and wherein the light-emitting surface is configured to emit light in the direction of the light-exit surface, the first metasurface is configured to concentrate the light emitted by the light-emitting surface relative to an axis of a third direction that is perpendicular to the light-emitting surface on the cross-sectional plane along the first direction, the light-exit surface is configured to receive the light emitted by the light-emitting surface and guided through the first metasurface,and the second metasurface is arranged to deflect the received light in a positive direction of the first direction or a negative direction of the first direction with respect to the axis of the third direction., Impact on the state of the art

[0004] With the display device provided by individual embodiments of the present invention, light can be emitted simultaneously at various predetermined viewing angles, and the emitted light at unnecessary angles can be reduced, thereby achieving a multi-viewing angle display while reducing optical loss. Therefore, the display device provided according to individual embodiments of the present invention can be applied to scenarios or situations with different predetermined display angles, and can improve the overall light efficiency and reduce or avoid possible interference from direct or indirect reflected light at unnecessary angles. DESCRIPTION OF THE INVENTION

[0005] In it show Fig. 1 is a schematic representation of a display device according to an embodiment of the present invention, Fig. 2 a schematic representation of the light emission of the display device according to an embodiment of the present invention, Fig. 3A to 3C each show a schematic representation of the light emission of the display device according to an embodiment of the present invention in different phases, Fig. 4 a schematic representation of the arrangement of a first metasurface and a second metasurface of the display device according to an embodiment of the present invention, Fig. 5 is a schematic representation of the arrangement of a first microstructure of the first metasurface of the display device according to an embodiment of the present invention, Fig. 6 is a schematic representation of the arrangement of the first microstructure of the first metasurface of the display device according to an embodiment of the present invention, Fig. 7 a schematic representation of the light emission light field over the first metasurface according to an embodiment of the present invention, Fig. 8 is a schematic representation of the arrangement of a second microstructure of the second metasurface of the display device according to an embodiment of the present invention, Fig. 9 is a schematic representation of the arrangement of the second microstructure of the second metasurface of the display device according to an embodiment of the present invention, Fig. 10 is a schematic representation of the light field generated by the first metasurface and the second metasurface according to an embodiment of the present invention, Fig. 11 is a schematic representation of the use of the display device according to an embodiment of the present invention for displaying for different viewing angles, Fig. 12 is a schematic representation of the use of a display device according to an embodiment of the present invention as a vehicle display, Fig. 13 is a schematic diagram illustrating reduction of light emission and reflection for unnecessary angles in the display device according to an embodiment of the present invention. CONCRETE EMBODIMENTS

[0006] Various embodiments are described below, and those skilled in the art should be able to easily understand the spirit and principles of the present invention with reference to the drawings. Although some specific embodiments are explained in detail, these embodiments are only exemplary and are not to be considered restrictive or exhaustive in all respects. Therefore, various changes and modifications of the invention should be obvious and readily achievable to those skilled in the art without departing from the spirit and principle of the invention.

[0007] With reference to Fig. 1 and Fig. 2, in the display device 10 according to an embodiment of the present invention, a double metasurface may be arranged in the light output path of the light source 100. For example, the display device 10, as shown in Fig. 1, be equipped with a plurality of subpixels P. For example, the display device 10 may be equipped with a plurality of subpixels P that can display different color light such as red light, green light, or blue light. In the display device 10, the plurality of light sources 100 corresponding to the plurality of subpixels P for light emission may be included, and hereinafter, the configuration architecture of a single light source 100 will be described mainly with reference to Fig. 2 described.

[0008] With reference to Fig. 2, the display device 10 according to the present invention may comprise: a light source 100 having a light-emitting surface 105 configured to emit light L; a light-transmitting layer 200 covering the light source 100 and having a light-exiting surface 205; a first metasurface 300 formed between the light-emitting surface 105 and the light-transmitting layer 200; and a second metasurface 400 formed on the light-exiting surface 205.

[0009] According to some embodiments, the light source 100 may be a single-sided light-emitting light source having the light-emitting surface 105 or a multi-sided light-emitting light source having the light-emitting surface 105 and other light-emitting surfaces for light emission. For example, according to some embodiments, the light source 100 may be a micro-LED (µLED) having multiple surfaces that emit light at a wide angle. However, the present invention is not limited thereto, and in addition to the micro-LED (µLED), various other light sources may be applied according to other embodiments.

[0010] The light-transmitting layer 200 covering the light source 100 may indirectly cover the light source 100 or at least partially come into direct contact with the light source 100 to cover the light source 100. Furthermore, according to some embodiments, the entire light source 100 may be enveloped by the light-transmitting layer 200, but the present invention is not limited thereto.

[0011] Here, according to some embodiments, the light-transmitting layer 200 may be fabricated using any material with light-transmitting properties that can transmit predetermined light (i.e., light from the light source 100). For example, polycarbonate (PC), polymethyl methacrylate (poly(methyl methacrylate), PMMA), acrylonitrile-butadiene-styrene (ABS), and so on are conceivable, but not limited thereto. Additionally, according to some embodiments, the light-transmitting layer 200 may also function as a protective layer (cover layer) for protecting the light source 100.

[0012] The light-exiting surface 205 of the light-transmitting layer 200 may be disposed opposite the light-emitting surface 105 of the light source 100 and may receive light emitted from the light-emitting surface 105 of the light source 100. For example, the light-emitting surface 105 of the light source 100 and the light-exiting surface 205 of the light-transmitting layer 200 may be the top surface of the light source 100 and the top surface of the light-transmitting layer 200, respectively.

[0013] Here, the structure for adjusting the light emission of the single light-emitting surface 105 of the light source 100 is mainly described.

[0014] In detail, the first metasurface 300, which is arranged between the light-emitting surface 105 and the light-transmitting layer 200, is configured to concentrate light onto the center of a cross-sectional plane along the first direction D1 of the light-emitting surface 105, for example, parallel to the first direction D1 of the light-emitting surface 105, which is relative to an axis of a third direction D3 that is perpendicular to the light-emitting surface 105, and the second metasurface 400 is configured to split light L' received by the light exit surface 205 into a positive direction of the first direction D1 and a negative direction of the first direction relative to the center (for example, with respect to the axis of the third direction D3).

[0015] In detail, as shown in the right part of Fig. 2, the light L emitted from the light source 100 via the light-emitting surface 105 can have a wide-angle light field and be emitted in all directions if no metasurface is provided. In this case, radiating light at a wide angle may cause undesirable light losses and is not suitable for displaying for a specific viewing angle. Therefore, according to the structure of the present embodiment, as shown in the left part of Fig. 2, the light originally emitted by the light source 100 as wide-angle light L is concentrated, after passing through the first metasurface 300, to the center of at least the cross-sectional plane along the first direction D1 and emitted as light L' with a concentrated convergent light field relative to the axis of the third direction D3.

[0016] According to some embodiments, for example, the first metasurface 300 may be arranged separately from the light-emitting surface 105 and thus between the light-emitting surface 105 and the light-transmitting layer 200 in order to achieve adaptation to the manufacturing process or to other possible functional layers on the light source 100. However, to improve the light utilization rate, the first metasurface 300 may also be arranged directly on the light-emitting surface 105 and thus between the light-emitting surface 105 and the light-transmitting layer 200.

[0017] Additionally, the first metasurface 300 can also concentrate light onto the center of the cross-sectional plane along a second direction D2 parallel to the light-emitting surface 105 and perpendicular to the first direction D1. Therefore, the light L' can effectively have a light field concentrated at least on the cross-sectional plane along the first direction D1 and further on the cross-sectional plane along the second direction D2 with respect to the light L originally emitted from the light source 100 through the light-emitting surface 105, thus concentrating light in the forward direction of the light-emitting surface 105.

[0018] The light L' is emitted through the light-transmitting layer 200 to the light-exit surface 205 of the light-transmitting layer 200 and received by the light-exit surface 205. The light L' received by the light-exit surface 205 is re-emitted via the second metasurface 400 disposed at the light-exit surface 205. Thus, after passing through the second metasurface 400, the light L' can be divided into light L1 and light L2 on the cross-sectional plane along the first direction D1 with respect to the center, which are emitted substantially at different viewing angles.

[0019] According to some embodiments, for example, the second metasurface 400 may be arranged separately from the light exit surface 205 and thus at the light exit surface 205 in order to achieve adaptation to the manufacturing process or to other possible functional layers on the light-transmissive layer 200. However, to improve the light utilization rate, the second metasurface 400 may also be formed directly at the light exit surface 205 and thus arranged at the light exit surface 205.

[0020] Additionally, similar to the first metasurface 300, the second metasurface 400 may serve to concentrate light relative to the axis of the third direction D3 perpendicular to the light-emitting surface 105 on the cross-sectional plane along the second direction D2. Alternatively, according to some embodiments, the second metasurface 400 may not have a specific concentrated or dispersed light effect relative to the axis of the third direction D3 perpendicular to the light-emitting surface 105 on the cross-sectional plane along the second direction D2.

[0021] As described above, the first metasurface 300 may be formed between the second metasurface 400 and the light-emitting surface 105 of the light source 100, and therefore, the light of the light source 100 may be sequentially transmitted through the first metasurface 300 and the second metasurface 400. Therefore, the outgoing light of the light source 100 may be sequentially concentrated and converged, and then split in a predetermined direction, such as a positive direction of the first direction D1 and a negative direction of the first direction D1 with respect to the axis of the third direction D3; and thus emitted at different viewing angles.

[0022] The emission of light by the light source 100 and its sequential passing through the first metasurface 300 and the second metasurface 400 are described with reference to Fig. 3A to 3C. In detail, Fig. 3A to Fig. 3C shows the degree of divergence of the outgoing light relative to the light-emitting surface 105 of the light source 100 when observing the display device 10 from above along the observation direction F according to Fig. 2. Fig. Figure 3A shows the light L emitted directly from the light source 100, which is relatively divergently distributed. Fig. Figure 3B shows the light L' emitted by the light source 100 via the first metasurface 300, which is converged and concentrated compared to light L on both the cross-sectional plane along the first direction D1 and the cross-sectional plane along the second direction D2. Finally, Fig. 3C shows the light L1, L2 emitted by the light source 100 and emitted after passing through the first metasurface 300 and the second metasurface 400. Compared to light L', the light L1 and L2 are split so that they deviate in a positive direction of the first direction D1 and a negative direction of the first direction D1, respectively.

[0023] In the display device 10 of the present embodiment, the light emitted via the first metasurface 300 for concentrating light with respect to the axis of the third direction D3 in the cross-sectional plane along the first direction D1 and the second metasurface 400 for splitting light can be substantially divided into light L1 and L2 in a positive direction of the first direction D1 and a negative direction of the first direction D1 with respect to the axis of the third direction D3, and emitted at different expected viewing angles, respectively. Therefore, the display device 10 according to the present embodiment can be configured to achieve display for different expected viewing angles, or can be applied to any case or situation in which the display device 10 needs to be viewed from different separate expected viewing angles.For example, it may be applied to the case where the display device 10 is viewed simultaneously from different angles, or it may be applied to a 3D display or the like.

[0024] The settings of the first meta-surface 300 and the second meta-surface 400 are explained in more detail below according to various embodiments.

[0025] With reference to Fig. 4, the display device 10' according to an embodiment of the present invention may have a structure identical to or similar to the first metasurface 300 and the second metasurface 400 of the display device 10, and may therefore concentrate light through the first metasurface 300 and then separate it through the second metasurface 400 to achieve a display effect with light emitted concentrated at different expected viewing angles. According to the configuration of the present embodiment, the first metasurface 300 of the display device 10' may include a plurality of first microstructures 350, and the second metasurface 400 of the display device 10' may include a plurality of second microstructures 450.

[0026] According to some embodiments, the material for forming the first metasurface 300 or the second metasurface 400 may be the same or different metal materials or dielectric materials with a high refractive index. The high refractive index dielectric material for forming the dielectric material of one of the first metasurface 300 and the second metasurface 400 may have a refractive index N1 or N2 that may be greater than the refractive index N of the light-transmissive layer 200. For example, the refractive index N1 or N2 of the dielectric material forming a plurality of first microstructures 350 and a plurality of second microstructures 450 may be greater than the refractive index N of the light-transmissive layer 200.The first microstructure 350 and the second microstructure 450 may be formed using the same or different metal material or dielectric material, and the pattern may be arranged according to the purpose of the predetermined light concentration or splitting task.

[0027] The first microstructures 350 and the second microstructures 450 may have tiny structures in sub-wavelength sizes and can therefore change the properties of the light, such as the exit angle, when arranged according to a specific configuration pattern. The sub-wavelength size means that the size and arrangement cycle of the first microstructure 350 and the second microstructure 450 can be smaller than the wavelength of the predetermined transmitted light. Influencing the properties of light can be based on the properties of the metasurface material, such as the refractive index and its arrangement. For example, the optical diffraction effect created by the configuration of the first metasurface 300 can concentrate the transmitted light, while the optical diffraction effect created by the configuration of the second metasurface 400 can split the transmitted light.

[0028] In general, the refractive index N of the light-transmitting layer 200 may be greater than the refractive index of air. Furthermore, according to some embodiments, the refractive index N of the light-transmitting layer 200 may also be greater than the refractive index of the light source 100, but is not limited thereto. For example, if the refractive index N of the light-transmitting layer 200 is approximately 1.45 to 1.5, and the first metasurface 300 or the second metasurface 400 is formed by a dielectric material, the refractive index N1 or N2 of the dielectric material for forming the first metasurface 300 or the second metasurface 400 may be greater than or equal to 2.0, for example.

[0029] In some embodiments, the material for forming the first metasurface 300 or the second metasurface 400 may be TiO2, Ag, or Ta2O5. According to some embodiments, when the first metasurface 300 or the second metasurface 400 is formed by a dielectric material, the refractive index of the dielectric material for forming the first metasurface 300 or the second metasurface 400 may be about 2, 2.15, 2.5, and the like. However, the above is only an example, and the present invention is not limited thereto.

[0030] Furthermore, when the first metasurface 300 or the second metasurface 400 is formed by a dielectric material, the refractive index N1 or N2 of the dielectric material for forming the first metasurface 300 or the second metasurface 400 may be adjusted depending on the refractive index N of the light-transmitting layer 200. For example, according to some embodiments, the refractive index N1 or N2 of a dielectric material for forming the first metasurface 300 or the second metasurface 400 may be at least about 0.5 or more greater than the refractive index N of the light-transmitting layer 200 in order to form the first metasurface 300 and / or the second metasurface 400 with high refractive index dielectric material properties relative to the light-transmitting layer 200.

[0031] Furthermore, according to some embodiments, the height H1 and H2 of the first microstructure 350 and the second microstructure 450 perpendicular to the light-emitting surface 105 may be less than 2000 nm. That is, the height H1 and H2 of the first microstructure 350 and the second microstructure 450 along the third direction D3 perpendicular to the light-emitting surface 105 may be less than 2000 nm. For example, the height H1 and H2 of the first microstructure 350 and the second microstructure 450 perpendicular to the light-emitting surface 105 may be about 500 nm, but is not limited thereto.

[0032] Furthermore, in some embodiments, to adjust the properties of the light, the first microstructure 350 of the first metasurface 300 or the second microstructure 450 of the second metasurface 400 may have different heights to increase the variability of the design arrangement pattern or to adjust the degree of expected concentration or splitting of the light. However, to facilitate process design and execution, the first microstructure 350 of the first metasurface 300 or the second microstructure 450 of the second metasurface may have the same height. The following illustrates the arrangement patterns of the first metasurface 300 and the second metasurface 400 based on the same height.

[0033] Additionally, according to various embodiments of the present invention, in addition to the structure of the light source 100, the light-transmitting layer 200, the first metasurface 300, and the second metasurface 400, the display device 10' may be further equipped with other components that are commonly used in the display device. For example, as shown in Fig. As shown in Figure 4, according to some embodiments, the display device 10' may further include components such as a circuit board 500, which is further electrically connected to the light source 100 as a power supply. The circuit board 500 or these components, which are not specifically illustrated, are components that are conventional in the field of display devices and are optionally used. Separate explanation is omitted in the description and drawings.

[0034] In the following, the arrangement of the first microstructure 350 of the first metasurface 300 according to some embodiments of the present invention will be described with reference to Fig. 5 and Fig. 6 illustrates.

[0035] If, according to some embodiments, the first metasurface 300 is directly from the observation direction F of Fig. 4, the first microstructure 350 of the first metasurface 300 may, for example, have an arrangement that is Fig. 5 or Fig. 6. For example, the shape of the cross section A1 of the first microstructures 350 parallel to the light-emitting surface 105 may be a circle, as shown in Fig. 5, or a square, as in Fig. 6, but is not limited thereto. In order to achieve a wide-angle light gathering effect, the first microstructure 350 of the first metasurface 300 may have a cross-sectional shape that has no obvious differences between the long axis / long edge and the short axis / short edge, or has slight differences between the long axis / long edge and the short axis / short edge. This can achieve an average light concentrating and converging effect at any viewing angle. However, the above is only an example. As far as the expected light concentrating and converging effect is achievable, the cross-sectional shape of the first microstructure 350 of the first metasurface 300 according to other embodiments of the present invention is not limited to the shape shown in this description and the drawings, but may have various variations or modifications.

[0036] According to some embodiments, as in Fig. 5 or Fig. 6, a plurality of first microstructures 350 may be arranged parallel to the light-emitting surface 105 to form a plurality of circles of first microstructures 350. For example, the first metasurface 300 may have first microstructures 350 arranged circumferentially in a first circle C1, a second circle C2, a third circle C3, a fourth circle C4, a fifth circle C5, and a sixth circle C6. However, according to some embodiments, the outermost or innermost first microstructures 350 may be arranged in an incomplete circle according to the area of the first metasurface 300. For example, as shown in Fig. 5 or Fig. 6, the first microstructures 350 of the sixth circle C6 may be arranged substantially linearly and may not form a complete circle.

[0037] In addition, according to the present embodiment, the cross section A1 of the plurality of first microstructures 350 of the first metasurface 300 parallel to the light-emitting surface 105 may have a size difference.

[0038] For example, with reference to Fig. 5 or Fig. 6, the sizes of the cross-sections A1 of the first microstructures 350 parallel to the light-emitting surface 105 exhibit a size change such that they gradually decrease from the outer circles to the inner circles, and such a size change may be repeated one or more times to arrange the plurality of circles of the first microstructures 350. For example, the cross-section A1 of the first microstructures 350 of the first circle C1 may have a width S1, the cross-section A1 of the first microstructures 350 of the second circle C2 may have a width S2, and the cross-section A1 of the first microstructures 350 of the third circle C3 may have a width S3. The width S1, the width S2, and the width S3 may decrease sequentially, so that the cross-section A1 of the first microstructures 350 sequentially shrinks from the first circle C1 of the outer circles to the second circle C2 and the third circle C3 of the inner circles.

[0039] According to the present embodiment, when the size decreases from the first circle C1 of the outer circles to the third circle C3 of the inner circles to a predetermined size, adjustment toward the inner circles is conceivable again to a larger size, and the size change of the decrease from the outer to the inner circles is repeated. For example, the cross section A1 of the first microstructures 350 of the fourth circle C4 may again have the width S1, and then the cross sections A1 of the first microstructures 350 are shrinked sequentially from the fourth circle C4 of the outer circles to the fifth circle C5 and the sixth circle C6 of the inner circles. That is, the fourth circle C4, the fifth circle C5, and the sixth circle C6 may have the width S1, the width S2, and the width S3 of the cross sections A1 of the first microstructures 350, which decrease sequentially.

[0040] As described above, the size changes of the decrease from the outer to the inner circles can be repeated one or more times, thereby arranging the first microstructures 350 in multiple circles to form the first metasurface 300. This can create the effect of concentrating the light by the first metasurface 300 to the center.

[0041] According to some embodiments, the first microstructures 350 of the innermost circle C6 (e.g., the first microstructures 350 closest to the center point O1 of the first metasurface 300 and having the same size) may have the smallest cross-section A1. For example, the first microstructures 350 of the innermost circle C6 may have a width S3 of the smallest cross-section A1.

[0042] According to some embodiments, the widths S1, S2 and S3 of the cross sections A1 of the first microstructures 350 parallel to the light-emitting surface 105 may be between 20 and 2000 nm.

[0043] When arranging the circumferentially distributed circles, the distances between the cross sections A1 of the first microstructures 350 parallel to the light-emitting surface 105 can also have a distance change such that they gradually decrease from the outer circle C1 to the inner circle C3, and such a distance change is repeated one or more times to arrange the first microstructures 350 in multiple circles. For example, the cross sections A1 of the first microstructures 350 of the first circle C1 can have a distance g1 therebetween, the cross sections A1 of the first microstructures 350 of the second circle C2 can have a distance g2 therebetween, and the cross sections A1 of the first microstructures 350 of the third circle C3 can have a distance g3 therebetween.The distances g1, g2, and g3 may decrease sequentially, so that the distances of the cross-sections A1 of the first microstructures 350 decrease sequentially from the first circle C1 of the outer circles to the second circle C2 and the third circle C3 of the inner circles. In the present embodiment, the distance may be defined as the distance between the edges of adjacent first microstructures 350 in the same circle.

[0044] When the distance from the first circle C1 of the outer circles to the third circle C3 of the inner circles decreases to a predetermined value, an adjustment to a larger distance toward the inner circles is conceivable according to the present embodiment, and the distance change of the decrease from the outer to the inner circles is repeated. For example, the cross sections A1 of the first microstructures 350 of the fourth circle C4 can again have the distance g1, and then a decrease in the distances between the cross sections A1 of the first microstructures 350 occurs sequentially from the fourth circle C4 of the outer circles to the fifth circle C5 and the sixth circle C6 of the inner circles.That is, the fourth circle C4, the fifth circle C5, and the sixth circle C6 may have the distance g1, the distance g2, and the distance g3 of the cross sections A1 of the first microstructures 350 therebetween, which decrease sequentially.

[0045] As described above, the gradually decreasing change in distance from the outer to the inner circles can be repeated one or more times, thereby arranging the first microstructures 350 in multiple circles to form the first metasurface 300. This can create the effect of concentrating light by the first metasurface 300 toward the center.

[0046] According to some embodiments, the first microstructures 350 of the innermost circle C6 (e.g., the first microstructures 350 closest to the center point O1 of the first metasurface 300 and having the same size) may have the smallest distance between the cross sections A1. For example, the first microstructures 350 of the innermost circle C6 may have the smallest distance g3 of the cross sections A1.

[0047] Furthermore, according to some embodiments, it is conceivable that in a single cycle of size change, in which a decrease gradually occurs from the outer circles to the inner circles, the spacing between the cross-sections A1 of the first microstructures 350 of adjacent circles running parallel to the light-emitting surface 105 changes such that it gradually decreases from the outer circles to the inner circles, and in other cycles, the first microstructures 350 are arranged in multiple circles according to this spacing change or a similar spacing change. For example, a spacing G12 may be present between the cross-sections A1 of the first microstructures 350 of the first circle C1 and the second circle C2, and a spacing G23 may be present between the cross-sections A1 of the first microstructures 350 of the second circle C2 and the third circle C3.The gaps G12 and G23 can decrease sequentially, so that the gap between the cross-sections A1 of the first microstructures 350 between the first circle C1 and the second circle C2 of the outer circles and the gap between the second circle C2 and the third circle C3 of the inner circles decrease sequentially. In the present embodiment, the gap is defined as the distance between the connecting lines of the centers of the first microstructures 350 of adjacent circles.

[0048] Similarly, in the next resizing cycle, the gap G45 between the fourth circle C4 and the fifth circle C5 of the outer circumference and the gap G56 between the fifth circle C5 and the sixth circle C6 of the inner circumference may sequentially decrease. That is, the fourth circle C4 to the sixth circle C6 may have a gap G45 and a gap G56 between the cross sections A1 of the first microstructures 350 of the adjacent circles that sequentially decrease.

[0049] As described above, the gradually decreasing gap change from the outer to the inner circles can be repeated one or more times, thereby arranging the first microstructures 350 in multiple circles to form the first metasurface 300. This can create the effect of concentrating light by the first metasurface 300 toward the center.

[0050] According to some embodiments, a minimum gap may be present between the cross-sections A1 of the first microstructures 350 of the innermost adjacent circles of different sizes. For example, a minimum gap G56 may exist between the cross-sections A1 of the first microstructures 350 of the fifth circle C5 and the sixth circle C6 as the innermost circles.

[0051] The distance between the cross sections A1 of the first microstructures 350 running parallel to the light-emitting surface 105, such as the distances g1, g2 and g3, or the gap between the cross sections A1 of the first microstructures 350 running parallel to the light-emitting surface 105 of adjacent circles, such as the gaps G12, G23, G45 and G56, can each be less than 2000 nm.

[0052] As shown above, the first metasurface 300 can cause the light L emitted by the light source 100 to be guided in a concentrated manner and thus form a concentrated light L'. For example, with reference to Fig. 7 conceivable that if the first microstructures 350 according to Fig. 5 are arranged to form the first metasurface 300, and in a section along the first direction D1 and the third direction D3, an angle with respect to the axis of the third direction D3 is defined as the respective viewing angle taking a direction perpendicular to the light-emitting surface 105 and along the third direction D3 as 0 degrees, the light passing through the first metasurface 300 forms a concentrated light distributed approximately in a light field FL' within + / -15 degrees.

[0053] As described above, the first microstructures 350 can be formed according to Fig. 5 or Fig. 6 to form the first metasurface 300 for concentrating light. However, the first metasurface 300 is not limited to this arrangement configuration; rather, the first metasurface 300 may have other arrangement configurations according to other embodiments of the present invention, as long as light can be concentrated.

[0054] In the following, the arrangement of the second microstructure 450 of the second metasurface 400 according to some embodiments of the present invention will be described with reference to Fig. 8 and Fig. 9 illustrates.

[0055] If, according to some embodiments, the second metasurface 400 is directly from the observation direction F of Fig. 4, the second microstructure 450 of the second metasurface 400 may, for example, have an arrangement that is Fig. 8 or Fig. 9. For example, the shape of the cross section A2 of the second microstructures 450 parallel to the light-emitting surface 105 has a short axis / edge along the first direction D1 and a long axis / edge along the second direction D2, which runs parallel to the light-emitting surface 105 and perpendicular to the first direction D1. For example, the cross section A2 of the second microstructures 450 parallel to the light-emitting surface 105 can be rectangular, as shown in Fig. 8, or elliptical, as in Fig. 9, but not limited thereto.

[0056] According to some embodiments, as in Fig. 8 or Fig. 9, the plurality of second microstructures 450 may be arranged along the first direction D1. For example, it is conceivable that at least one second microstructure 450 is arranged in a column in the second direction D2 and the second microstructures 450 are arranged in a plurality of columns along the first direction D1.

[0057] The width of the cross sections A2 of the adjacent second microstructures 450 parallel to the light-emitting surface 105 may differ from one another in the first direction D1. For example, the size of the cross section A2 of the second microstructures 450 parallel to the light-emitting surface 105 may exhibit a size change such that it gradually decreases from the two ends of the second metasurface 400 (ie, the end points E1, E2) toward the center point O2 along the first direction D1, and such a size change is repeated one or more times from both ends toward the center point O2 to arrange the second microstructures 450.

[0058] For example, six columns of second microstructures 450 may be arranged from an end point E1 to the center point O2 along the first direction D1, namely the second microstructures 450 of a first column Q1, a second column Q2, a third column Q3, a fourth column Q4, a fifth column Q5, and a sixth column Q6. The second microstructures 450 of the first column Q1, the second column Q2, and the third column Q3 may be adjusted along the first direction D1 such that their sizes gradually decrease and they have the widths W1, W2, and W3 in the first direction D1. The second microstructures 450 of the fourth column Q4, the fifth column Q5, and the sixth column Q6 may be adjusted along the first direction D1 such that their sizes gradually decrease and they have the widths W1, W2, and W3 in the first direction D1.Here, the width W1 may be greater than the width W2, and the width W2 may be greater than the width W3. Similarly, six columns of second microstructures 450 may be arranged symmetrically from the other end point E2 to the center O2 along the first direction D1, and their setting may correspond to the above content and will not be explained in detail here.

[0059] As mentioned above, the size change in the form of a decrease from one end (e.g., the end point E1 or E2) toward the center point O2 can be repeated one or more times, whereby the second microstructures 450 are arranged in multiple columns to form the second metasurface 400. This can achieve that light passing through the second metasurface 400 is each split and concentrated at a predetermined viewing angle on both sides.

[0060] According to some embodiments, the widths W1, W2 and W3 of the cross sections A2 of the second microstructures 450 parallel to the light-emitting surface 105 in the first direction D1 may be between 20 and 2000 nm.

[0061] According to some embodiments, the length T of the cross section A2 of the second microstructure 450 parallel to the light-emitting surface 105 in the second direction D2 may be the same and may be between 20 and 4000 nm.

[0062] According to some embodiments, the innermost second microstructures 450 closest to the center point O2 may have the smallest cross section A2.

[0063] Furthermore, the distance between the cross sections A2 of the plurality of second microstructures 450, which are formed as in Fig. 8 or Fig. 9, parallel to the light-emitting surface 105, also have a distance change such that it increases from two ends of the second metasurface 400 (ie, the end points E1, E2) toward the center O2 along the first direction D1, and such a distance change is repeated one or more times to arrange the second microstructures 450. For example, a distance G1 may be present between the second microstructure 450 of the first column Q1 and the second microstructure 450 of the second column Q2, and the second microstructure 450 of the second column Q2 and the second microstructure 450 of the third column Q3 may have a distance G2. Here, a distance G1 may be present between the second microstructure 450 of the fourth column Q4 and the second microstructure 450 of the fifth column Q5, and the second microstructure 450 of the fifth column Q5 and the second microstructure 450 of the sixth column Q6 may have a distance G2.The distance G1 is smaller than the distance G2, so that during a single cyclic size change in the form of a size decrease, the distance between the cross sections A2 of the plurality of second microstructures 450 parallel to the light-emitting surface 105 can increase along the first direction D1 from the end point E1 to the center point O2. In the present embodiment, the distance can be defined as a distance between the edges of adjacent first microstructures 350.

[0064] Similarly, the distance change from the other end point E2 to the center point O2 can be adjusted symmetrically based on the above distance change from the end point E1 to the center point O2. Here, the distance G1' can be smaller than the distance G2', so that with a single cyclic size change in the form of a size decrease, the distance between the cross sections A2 of the plurality of second microstructures 450 parallel to the light-emitting surface 105 along the first direction D1 can increase from the end point E2 to the center point O2. This can ensure that light passing through the second metasurface 400 is each split and concentrated at a predetermined viewing angle on both sides. These settings should be clear with reference to the above explanations and will not be described in detail here.

[0065] The distance between the cross sections A2 of the second microstructures 450 parallel to the light-emitting surface 105, such as the distances G1, G2, G1' and G2', may each be less than 2000 nm.

[0066] In some embodiments, as in Fig. 8 and Fig. 9, along the second direction D2, two second microstructures 450 of the same size are arranged in a column such that their short axial side edges are adjacent and opposite each other. However, the present invention is not limited thereto, and according to other embodiments, a single second microstructure 450 may be used as a column, or three, four, or more second microstructures 450 may be arranged in a column such that their short axial side edges are adjacent and opposite each other. The number of second microstructures 450 arranged in a row and having the same size is not limited thereto.

[0067] As shown above, the light L' passed through the first metasurface 300 and thus concentrated can be further divided by the second metasurface 400 to deviate in a positive direction of the first direction D1 and in a negative direction of the first direction D1 with respect to the axis of the third direction D3, respectively, thereby forming light L1 and light L2 emitted for different viewing angles. That is, the second metasurface 400 can divide the light converged in the center into two types of directional fields. For example, with reference to Fig. 10 conceivable that if the second microstructures 450 according to Fig. 8 are arranged to form the second metasurface 400, and in a section along the first direction D1 and the third direction D3, an angle with respect to the axis of the third direction D3 is defined as the respective viewing angle taking a direction perpendicular to the light-emitting surface 105 and along the third direction D3 as 0 degrees, the light passing through the second metasurface 400 forms a light field FL'' in which light is split and emitted at approximately an angle of + / - 20 degrees, and the light emission corresponding to the 0-degree viewing angle of the forward direction is reduced or avoided.

[0068] For the light field FL'', the intensity of light emitted at the viewing angle of 0 degrees in the forward direction is smaller than the intensity of light split and emitted at an angle of about + / -20 degrees.

[0069] As mentioned above, the display device 10 or 10' of the individual embodiments of the present invention can be described with reference to the description of Fig. 1 to 10 cause the light L, which originally includes a wide angular range in terms of an angle relative to the axis of the third direction D3, for example, a very wide angular range of 0 to 90 degrees in terms of the angle relative to the axis of the third direction D3, to be concentrated and divided, thereby achieving light emission for various specific viewing angles. Therefore, the light loss of the unnecessary angle can be reduced, the light intensity of the various desired viewing angles can be increased, and application to scenarios or situations where displaying for various viewing angles is required and the luminous efficiency of the unnecessary angle is to be reduced is enabled.

[0070] The height, width, length, pitch, spacing, refractive index, number of provided components, number of repetitions of the change cycles, etc. in the above embodiments are examples and can be adjusted according to the color or other characteristics of the light emitted from the light source to be concentrated and divided, and the degree of expected concentration or the viewing angle of the light division. In other embodiments of the present invention, the height, width, length, pitch, spacing, refractive index, number of provided components, number of repetitions of the change cycles, etc. are not limited to the examples shown in this description with reference to the drawings.

[0071] Furthermore, according to some embodiments, a metamaterial layer may first be formed on the metasurface to be formed, and then an expected arrangement pattern corresponding to the metasurface is formed by an applicable process. However, the present invention is not limited to this, and rather, a metasurface having the expected arrangement pattern may be formed in any way. For example, when forming the first metasurface 300, the expected arrangement pattern may also be directly formed using a metal material on the light source 100 or a dielectric material with a high refractive index. Alternatively, a metasurface having the expected arrangement pattern may additionally be formed and then arranged on the metasurface to be formed to form, among other things, the first metasurface 300 and / or the second metasurface 400.

[0072] Hereinafter, an example of a scenario or situation in which the display device according to the individual embodiments of the present invention can be applied or used will be described with reference to Fig. 11 to 13 illustrates.

[0073] With reference to Fig. 11, a display device 20 is disclosed according to an embodiment that can be used for displaying to receivers at various fixed positions. The display device 20 may have a double metasurface structure that corresponds to one of the configurations described above with reference to Fig. 1 to 10. This allows the display device 20 to emit light for different expected viewing angles, and thus emit light L1 and light L2 that are divided to deviate in a positive direction of the first direction D1 and in a negative direction of the first direction D1 with respect to the axis of the third direction D3, toward the first position K1 and the second position K2, respectively. Therefore, when the first receiver U1 and the second receiver U2 are located at the first position K1 and the second position K2, the first receiver U1 and the second receiver U2 can receive light L1 and light L2, respectively, thereby viewing the content displayed by the display device 20.

[0074] In this case, in addition to the light L1 and the light L2 emitted for the display angle of the first position K1 and the second position K2, the light emitted for other angles can be reduced or avoided. For example, the emission of light L3 and light L4 can be directed in a positive direction of the second direction D2 and in a negative direction of the second direction D2 with respect to the axis of the third direction D3, respectively, as shown in Fig. 11 can be reduced or avoided. Therefore, unnecessary light loss can be reduced or avoided, and the luminous efficiency of the display device 20 can be improved.

[0075] Hereinafter, according to some embodiments, a display device corresponding to or similar to one of the above embodiments may be used as a vehicle display. For example, the display device 30 may be described with reference to Fig. 12 may have a double metasurface, as described in one of the embodiments described above, and is therefore arranged on the vehicle to emit light L1 and light L2 for indicating toward the driver's seat and the passenger seat, respectively. In this case, the first receiver U1 may be a driver sitting in the driver's seat, and the second receiver U2 may be a passenger sitting in the passenger seat.

[0076] According to the present embodiment, the display device 30 has a dual metasurface, wherein the first metasurface is configured to concentrate light, and the second metasurface is configured to divide concentrated light into a positive direction of the first direction D1 and a negative direction of the first direction D1, respectively. Therefore, the light efficiency for displaying toward the driver's seat and the passenger's seat can be improved, and the loss of light at unnecessary angles can be reduced or avoided. For example, this refers to the loss of light emitted toward the gap between the driver's seat and the passenger's seat, but is not limited to this.

[0077] It will be Fig. 12 and Fig. 13. Since the first metasurface and the second metasurface of the display device 30 can concentrate light in other directions, such as relative to an axis of the third direction D3 on a cross-sectional plane along the second direction D2, the light L3 or L4 in an unexpected direction, such as a positive direction of the second direction D2 and a negative direction of the second direction D2, can be reduced or avoided, thereby reducing the probability that, for example, the light L3 hits the windshield 1000 of the vehicle and is reflected to form reflected light L3'. Specifically, since in the light field of the display device 30, light is first concentrated and then emitted for a specific viewing angle, the light that might originally hit the windshield 1000, thus be reflected and affect the field of view for drivers, can be greatly reduced.Therefore, according to the present embodiment, when a display device 30 is used that has a double metasurface and can thus concentrate light and radiate it dividedly at a specific viewing angle, for example, in a positive direction of the first direction D1 or in a negative direction of the first direction D1, the light emitted from the display device 30 can be further reduced or avoided from being reflected by the windshield 1000. This can reduce or avoid interference from light emitted from an unnecessary angle or interference from light reflected by the windshield 1000. For example, the case where the driver is disturbed by the reflected light L3' when the first receiver U1 observes the road condition through the windshield 1000 can be avoided.

[0078] As described above, with the display device 30 according to the present embodiment used as a vehicle display, the luminous efficiency of the expected light emission can be improved, the light loss of the unexpected light emission can be reduced, and the visual disturbance caused by the unexpected light and its reflected light can be further reduced or avoided. Therefore, the display efficiency and light utilization efficiency of the display device 30 can be improved, the viewing experience can be enhanced, and driving safety can be further improved when the vehicle display is used.

[0079] As described above, the scenario or situation in which the display device with light splitting capability according to each embodiment of the present invention can be applied can be Fig.11 to 13. However, the above is only an example, and the display device of each embodiment of the present invention can also be used in other scenarios or situations based on the high directivity and high light utilization efficiency characteristics of the split-light display. The scenario or situation to which the present invention can be applied is not limited to the detailed description specifically shown here.

[0080] In summary, the display device according to each embodiment of the present invention can concentrate light and emit it separately at different viewing angles. Therefore, light loss and optical interference from unnecessary light can be reduced, power efficiency and light utilization rate can be effectively improved, and the display device according to each embodiment of the present invention can be used in any scenario or case where such a high-directivity display characteristic is required.

[0081] Thus far, only some of the preferred embodiments of the present invention have been explained. It should be noted that various changes and modifications are conceivable for the present invention without departing from the spirit and principle of the invention. Those having ordinary skill in the art should understand that the invention is defined by the scope of the appended claims, and that, within the scope of the invention, various changes such as substitutions, combinations, modifications, and alterations do not depart from the scope of the invention, which is defined by the scope of the appended claims. Reference symbol 10, 10', 20, 30 display device 100 light source 105 light-emitting surface 200 translucent layer 205 light exit area 300 first metasurface 350 first microstructure 400 second metasurface 450 second microstructure 500 circuit boards 1000 windshield A1, A2 cross section C1 first circle C2 second circle C3 third circle C4 fourth circle C5 fifth circle C6 sixth circle D1 first direction D2 second direction D3 third direction E1, E2: Endpoint F Observation direction FL', FL'' light field g1, g2, g3, G1, G2, G1', G2' distance G12, G23, G45, G56 gap H1, H2 height K1 first position K2 second position L, L', L1, L2, L3, L4, L3' light N, N1, N2 refractive index O1, O2 center P subpixel Q1 first column Q2 second column Q3 third column Q4 fourth column Q5 fifth column Q6 sixth column S1, S2, S3 width T Length U1 first receiver U2 second receiver W1, W2, W3 width

Claims

[1] Display device (10, 10', 20, 30), comprising: a light source (100) having a light-emitting surface (105); a light-transmitting layer (200) covering the light source (100); wherein the light-transmitting layer (200) has a light-exiting surface (205); a first metasurface (300) formed between the light-emitting surface (105) and the light-transmitting layer (200), wherein the first metasurface (300) has a plurality of first microstructures (350), and the first microstructures (350) are arranged parallel to the light-emitting surface (105) to form a plurality of circles, wherein the sizes of the cross sections of the first microstructure (350) parallel to the light-emitting surface (105) change such that they gradually decrease from the outer to the inner circles, wherein such a size change is repeated one or more times to arrange the plurality of circles of the first microstructures (350); and a second metasurface (400) formed on the light exit surface (205), wherein the second metasurface (400) has a plurality of second microstructures (450) and the shape of the cross section of the second microstructure (450) parallel to the light-emitting surface (105) has a short axis along a first direction (D1) that is parallel to the light-emitting surface (105), and a long axis along a second direction (D2) that is parallel to the light-emitting surface (105) and perpendicular to the first direction (D1), and wherein the light-emitting surface (105) is configured to emit light in the direction of the light-exit surface (205), the first metasurface (300) is configured to concentrate the light emitted by the light-emitting surface (105) relative to an axis of a third direction (D3) that is perpendicular to the light-emitting surface (105) on the cross-sectional plane along the first direction (D1), the light-exit surface (205) is configured to receive the light emitted by the light-emitting surface (105) and guided through the first metasurface (300), and the second metasurface (400) is configured to deflect the received light in a positive direction of the first direction (D1) and a negative direction of the first direction (D1) with respect to the axis of the third direction (D3). [2] Display device (10, 10', 20, 30) according to claim 1, equipped with a plurality of subpixels (P), wherein a plurality of the light sources (100) are respectively contained in the subpixels (P). [3] Display device (10, 10', 20, 30) according to claim 1, wherein the light source (100) is a micro-LED (micro LED, µLED). [4] The display device (10, 10', 20, 30) of claim 1, wherein the first metasurface (300) and the second metasurface (400) are configured to concentrate the light relative to the axis of the third direction (D3) on the cross-sectional plane along the second direction (D2). [5] Display device (10, 10', 20, 30) according to claim 1, wherein the first microstructures (350) have the smallest cross-section in the innermost circle. [6] The display device (10, 10', 20, 30) according to claim 1, wherein the distances between the cross sections of the first microstructures (350) parallel to the light-emitting surface (105) change so as to gradually decrease from the outer to the inner circles, and such a distance change is repeated one or more times to arrange the plurality of circles of the first microstructures (350). [7] Display device (10, 10', 20, 30) according to claim 1, wherein the second microstructures (450) are arranged in the first direction (D1). [8] The display device (10, 10', 20, 30) according to claim 7, wherein the sizes of the cross sections of the second microstructures (450) parallel to the light-emitting surface (105) change so as to decrease along the first direction (D1) from both ends of the second metasurface (400) to the center, and such a change in size from both ends to the center is repeated one or more times to arrange the second microstructures (450). [9] The display device (10, 10', 20, 30) of claim 8, wherein the innermost second microstructures (450) closest to the center have the smallest cross-section. [10] The display device (10, 10', 20, 30) according to claim 7, wherein the distances between the cross sections of the second microstructures (450) parallel to the light-emitting surface (105) change so as to decrease along the first direction (D1) from both ends of the second metasurface (400) to the center, and such a change in size is repeated one or more times to arrange the second microstructures (450). [11] Display device (10, 10', 20, 30) according to claim 1, wherein the width of the cross section of the first microstructures (350) parallel to the light-emitting surface (105) is between 20 and 2000 nm. [12] Display device (10, 10', 20, 30) according to claim 1, wherein the width of the cross section of the second microstructures (450) parallel to the light-emitting surface (105) in the first direction (D1) is between 20 and 2000 nm, while the length of the cross section of the second microstructures (450) parallel to the light-emitting surface (105) along the second direction (D2) is between 20 and 4000 nm. [13] Display device (10, 10', 20, 30) according to claim 12, wherein the width of the cross sections of the adjacent second microstructures (450) parallel to the light-emitting surface (105) differ from each other in the first direction (D1). [14] The display device (10, 10', 20, 30) of claim 1, wherein both the distance between the cross sections of the first microstructures (350) parallel to the light-emitting surface (105) and the distance between the cross sections of the second microstructures (450) parallel to the light-emitting surface (105) are less than 2000 nm. [15] Display device (10, 10', 20, 30) according to claim 1, wherein the first microstructures (350) and the second microstructures (450) have a height of less than 2000 nm perpendicular to the light-emitting surface (105). [16] The display device (10, 10', 20, 30) according to claim 1, wherein the first metasurface (300) or the second metasurface (400) is made of a dielectric material and the refractive index of the dielectric material for forming the first metasurface (300) or the second metasurface (400) is greater than the refractive index of the light-transmitting layer (200).

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