Optical device

Abstract

An optical device has a central region and a first type region, wherein the first type region surrounds the central region. The first type region includes a first sub-region and a second sub-region, wherein the second sub-region is between the central region and the first sub-region. The optical device includes a substrate. The optical device also includes a metastructure, wherein the metastructure is disposed on the substrate. The metastructure includes a plurality of first guide pillars and second guide pillars, wherein the first guide pillars are located in the first sub-region, and the second guide pillars are located in the second sub-region. In a cross section of the optical device cut along a radiation direction of the optical device, two adjacent first guide pillars have a first spacing, and two adjacent second guide pillars have a second spacing, and the second spacing is greater than the first spacing.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to an optical device, and more particularly, to an optical device including a metastructure having different pitches. Background Art

[0002] Typically, conventional optical lenses, such as color filters, focusing lenses, and beam splitters, must be combined to provide specific functions. Furthermore, to eliminate chromatic effects (which degrade performance in full-color imaging applications), designers must integrate multiple lenses with opposite dispersions. These conventional optical lenses can make the final device in which they are used bulky.

[0003] In recent years, thin lenses with focusing effects, called meta-lenses, have been developed. Meta-lenses have nanostructures that use high-refractive-index materials to alter the optical phase. This structure significantly reduces the size and weight of traditional optical lenses.

[0004] However, existing metalenses are not satisfactory in all aspects. For example, typical metalens structures have pillars with a constant (or fixed) pitch in each region (e.g., the edge or peripheral region). This can result in reduced light collection efficiency. Summary of the Invention

[0005] In a metalens, a specific area scheme is defined for a specific deflection angle of light by the number of guide pillars, process limitations (pitch), scaling factors, etc. According to an embodiment of the present disclosure, an optical device is provided that includes a metastructure with varying pitches to improve light collection efficiency.

[0006] Some embodiments of the present disclosure include an optical device. The optical device has a central region and a first type region, the first type region surrounding the central region. The first type region includes a first sub-region and a second sub-region, the second sub-region being between the central region and the first sub-region. The optical device includes a substrate. The optical device also includes a metastructure, which is disposed on the substrate. The metastructure includes a plurality of first guide pillars and second guide pillars, the first guide pillars being located in the first sub-region, and the second guide pillars being located in the second sub-region. In a cross-section of the optical device cut along a radiation direction of the optical device, two adjacent first guide pillars have a first spacing, two adjacent second guide pillars have a second spacing, and the second spacing is greater than the first spacing.

[0007] In some embodiments, in a cross section of the optical device cut along a radiation direction of the optical device, the number of the first guiding pillars is the same as the number of the second guiding pillars.

[0008] In some embodiments, in a cross section of the optical device cut along a radiation direction of the optical device, the first sub-region has a first region width, the second sub-region has a second region width, and the second region width is greater than the first region width.

[0009] In some embodiments, in a cross section of the optical device cut along a radiation direction of the optical device, the first guiding pillars have different widths, and the second guiding pillars have different widths.

[0010] In some embodiments, the first guide pillar includes a first specific guide pillar and a second specific guide pillar adjacent to the first specific guide pillar, the first specific guide pillar is closer to the second sub-region than the second specific guide pillar, and the width of the first specific guide pillar is greater than the width of the second specific guide pillar.

[0011] In some embodiments, the second guide pillar includes a third specific guide pillar and a fourth specific guide pillar, the third specific guide pillar corresponds to the first specific guide pillar, the fourth specific guide pillar corresponds to the second specific guide pillar, and the width of the third specific guide pillar is greater than that of the fourth specific guide pillar.

[0012] In some embodiments, a width of the third specific guide pillar is greater than a width of the first specific guide pillar.

[0013] In some embodiments, a width of the fourth specific guide pillar is greater than a width of the second specific guide pillar.

[0014] In some embodiments, the optical device further comprises a second-type region located between the central region and the first-type region, and the second-type region comprises a plurality of third sub-regions. The metastructure further comprises a plurality of third guide pillars, each of which is located in each of the third sub-regions.

[0015] In some embodiments, in a cross section of the optical device cut along a radiation direction of the optical device, the number of the third guide pillars is greater than the number of the first guide pillars and the number of the second guide pillars.

[0016] In some embodiments, in a cross section of the optical device cut along a radiation direction of the optical device, the third guiding pillars in each third sub-region have different widths.

[0017] In some embodiments, in a cross section of the optical device cut along a radiation direction of the optical device, a maximum width of the third guiding pillar is greater than a maximum width of the first guiding pillar.

[0018] In some embodiments, a height of each third guide pillar is lower than a height of each first guide pillar and a height of each second guide pillar.

[0019] In some embodiments, light entering the second type region perpendicularly deviates by 15 degrees or less from a normal to the optical device after passing through the second type region.

[0020] In some embodiments, in a cross section of the optical device cut along a radiation direction of the optical device, the number of the first guiding pillars and the number of the second guiding pillars are greater than or equal to four.

[0021] In some embodiments, the optical device further includes a Fresnel lens, wherein the Fresnel lens is disposed adjacent to the metastructure and located in the central region.

[0022] In some embodiments, the optical device further includes an anti-reflection layer disposed on the metastructure.

[0023] In some embodiments, the optical device further includes a protective layer disposed between the substrate and the anti-reflection layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The following will be described in detail with reference to the accompanying drawings. It should be noted that the various features are not drawn to scale and are for illustration purposes only. In fact, the size of the components may be enlarged or reduced to clearly show the technical features of the embodiments of the present disclosure.

[0025] Figure 1 A partial top view of an optical device according to an embodiment of the present disclosure is shown.

[0026] Figure 2 Is displayed along Figure 1 Partial cross-sectional view of the optical device taken along line AA'.

[0027] Figure 3 Is displayed along Figure 1 Partial cross-sectional view of the optical device taken along line AA”.

[0028] Figure 4 A partial cross-sectional view of an optical device according to another embodiment of the present disclosure is shown.

[0029] Figure 5 A partial cross-sectional view of an optical device according to another embodiment of the present disclosure is shown.

[0030] The reference numerals are as follows:

[0031] 100, 102, 104: Optical devices

[0032] 10:Substrate

[0033] 20: Metastructure

[0034] 211,211-1,211-2,211-4,212,212-1,212-2,213,213-1,213-2,221,221',222,221-1,221-2,222-1,222-2: Guide column

[0035] 30: Protective layer

[0036] 40: Anti-reflection layer

[0037] A-A',AA": line

[0038] C: Central area

[0039] D111, D112, D121, D122, D131, D132, D211, D212, D221, D222: Width

[0040] H1,H2:Height

[0041] L: Light

[0042] L': Outgoing light

[0043] N: Normal

[0044] P11, P12, P13, P21, P22: Spacing

[0045] R: Radiation direction

[0046] T1: Type 1 region

[0047] T11, T12, T13: sub-areas

[0048] T2: Type II region

[0049] T21, T22: sub-areas

[0050] W11, W12, W13, W21, W22: Area width

[0051] X, Y, Z: coordinate axes

[0052] θ: Angle DETAILED DESCRIPTION

[0053] The following disclosure provides many different embodiments or examples for implementing the different features of the present invention. The following disclosure describes specific examples of various components and their arrangement to simplify the description. Of course, these specific examples are not intended to be limiting. For example, if the embodiment of the present disclosure describes a first characteristic component formed on or above a second characteristic component, it means that it may include an embodiment in which the first characteristic component and the second characteristic component are in direct contact, and may also include an embodiment in which an additional characteristic component is formed between the first characteristic component and the second characteristic component, so that the first characteristic component and the second characteristic component may not be in direct contact.

[0054] It should be understood that additional operating steps may be implemented before, during, or after the method, and in other embodiments of the method, some operating steps may be replaced or omitted.

[0055] Additionally, spatially relative terms such as "below," "beneath," "below," "above," "upper," and the like may be used to describe the relationship of one element or feature to another element or feature in the drawings. These spatially relative terms encompass different orientations of the device in use or operation, as well as the orientations depicted in the drawings. When the device is oriented differently (rotated 90 degrees or at other orientations), the spatially relative adjectives used herein will be interpreted based on that orientation.

[0056] In the specification, the terms "about", "approximately", and "substantially" generally mean within 20%, within 10%, within 5%, within 3%, within 2%, within 1%, or within 0.5% of a given value or range. The quantities given here are approximate quantities, that is, in the absence of specific description of "about", "approximately", and "substantially", the meaning of "about", "approximately", and "substantially" can still be implied.

[0057] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meanings as commonly understood by those skilled in the art to which this disclosure belongs. It is understood that these terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the background or context of the relevant technology and this disclosure, and should not be interpreted in an idealized or overly formal manner unless specifically defined in the embodiments of the present disclosure.

[0058] The different embodiments disclosed below may reuse the same reference symbols and / or signs. Such repetition is for the purpose of simplicity and clarity and is not intended to limit any specific relationship between the different embodiments and / or structures discussed.

[0059] Figure 1 FIG. 1 shows a partial top view of an optical device 100 according to an embodiment of the present disclosure. Figure 2 Is displayed along Figure 1 Partial cross-sectional view of the optical device 100 cut along line AA' in FIG. Figure 3 Is displayed along Figure 1 AA" in FIG. 1 is a partial cross-sectional view of the optical device 100. It should be noted that for simplicity, Figure 1 、 Figure 2 and Figure 3 Some components of the optical device 100 may be omitted.

[0060] Reference Figure 1 In some embodiments, the optical device 100 has (or can be divided into) a central region C and a first-type region T1, which surrounds the central region C. For example, the first-type region T1 may be located at the edge (peripheral) region of the optical device 100. In some embodiments, the optical device 100 is circular in top view. For example, the diameter of the optical device 100 may be in the range of approximately 10 μm to approximately 100 μm, but the disclosed embodiments are not limited thereto.

[0061] In some embodiments, the first type region T1 includes multiple sub-regions. Figure 2 As shown, the first type region T1 may include a sub-region T11, a sub-region T12, and a sub-region T13. Sub-region T12 is located between the central region C and sub-region T11, while sub-region T13 is located between the central region C and sub-region T12. However, the disclosed embodiments are not limited to this. The number of sub-regions in the first type region T1 may be, for example, greater than sixty, depending on actual needs or process limitations.

[0062] Reference Figure 2 In some embodiments, the optical device 100 includes a substrate 10. For example, the substrate 10 may include silicon oxide (SiO2), a polymer with a refractive index of approximately 1.5 (e.g., polymethylmethacrylate (PMMA), polydimethylsiloxane (PDMS), polymethylpentene (PMP)), or a combination thereof, but the disclosed embodiments are not limited thereto. Alternatively, the substrate 10 may be a semiconductor-on-insulator (SOI) substrate.

[0063] Reference Figure 2In some embodiments, the optical device 100 includes a metastructure 20 disposed on a substrate 10. In some embodiments, the metastructure 20 includes a plurality of guide pillars 211 located in the sub-region T11 and a plurality of guide pillars 212 located in the sub-region T12. For example, each guide pillar 211 or each guide pillar 212 may include single crystal silicon, polycrystalline silicon, amorphous silicon, Si3N4, GaP, TiO2, AlSb, AlAs, AlGaAs, AlGaInP, BP, ZnGeP2, other suitable materials, or combinations thereof, but the present disclosure is not limited thereto.

[0064] A cross section of the optical device 100 cut along the radiation direction R of the optical device 100 (eg, Figure 2 In the cross section of the optical device 100 shown in FIG, the guide pillars located in the same sub-region have the same pitch. Figure 2 As shown, the guide pillars 211 located in the sub-region T11 may have a pitch P11, and the guide pillars 212 located in the sub-region T12 may have a pitch P12.

[0065] In some embodiments, two adjacent guide pillars 211 (e.g., guide pillar 211-1 and guide pillar 211-2) have a spacing P11, and two adjacent guide pillars 212 (e.g., guide pillar 212-1 and guide pillar 212-2) have a spacing P12, and spacing P12 is greater than spacing P11. Here, spacing P11 can be defined as the distance from the central axis of one guide pillar 211 to the central axis of an adjacent guide pillar 211. Similarly, spacing P12 can be defined as the distance from the central axis of one guide pillar 212 to the central axis of an adjacent guide pillar 212.

[0066] In some embodiments, a cross section of the optical device 100 cut along the radiation direction R of the optical device 100 (eg, Figure 2 In the cross section of the optical device 100 shown in FIG, the number of guide pillars in each sub-region of the first type region T1 is the same. Figure 2 As shown, there are four guide pillars 211 in the sub-region T11 and four guide pillars 212 in the sub-region T12, but the present disclosure is not limited thereto. In some other embodiments, there may be more than four guide pillars 211 in the sub-region T11 and more than four guide pillars 212 in the sub-region T12.

[0067] In some embodiments, a cross section of the optical device 100 cut along the radiation direction R of the optical device 100 (eg, Figure 2In the cross-section of optical device 100 shown in FIG. 1 , sub-region T11 has a region width W11, and sub-region T12 has a region width W12, where region width W12 is greater than region width W11. In some embodiments, pitches P11 and P12 are determined based on region width W11 of sub-region T11 and region width W12 of sub-region T12, respectively. The region widths W11 and W12 of sub-region T11 and sub-region T12 can be defined for a specific deflection angle of light.

[0068] In some embodiments, a cross section of the optical device 100 cut along the radiation direction R of the optical device 100 (eg, Figure 2 In the cross-section of optical device 100 shown in FIG. 1 , guide pillars 211 in sub-region T11 have different widths, while guide pillars 212 in sub-region T12 have different widths. For example, guide pillars 211 and 212 may be circular, and the diameters of these circles may vary. The diameters of these circles may range from approximately 0.15 μm to approximately 0.30 μm, but the disclosed embodiments are not limited thereto.

[0069] In some embodiments, as Figure 2 As shown, the guide post 211-1 is closer to the sub-region T12 than the guide post 211-2, and the width D111 of the guide post 211-1 is greater than the width D112 of the guide post 211-2. In addition, the guide post 211-2 is closer to the sub-region T12 than the guide post 211-4, and the width D112 of the guide post 211-2 is greater than the width D112 of the guide post 211-4 (not shown). Figure 2 That is, the closer the guide pillar 211 is to the central region C (or sub-region T12), the larger its width is.

[0070] In some embodiments, as Figure 2 As shown, the guide pillar 212-1 in the sub-region T12 corresponds to the guide pillar 211-1 in the sub-region T11, and the guide pillar 212-2 in the sub-region T12 corresponds to the guide pillar 211-2 in the sub-region T11. The width D121 of the guide pillar 212-1 is greater than the width D122 of the guide pillar 212-2. Similarly, the closer the guide pillar 212 is to the central region C (or sub-region T13), the larger its width.

[0071] In some embodiments, the width of the guide pillar 211 in the sub-region T11 is greater than the width of the corresponding guide pillar 212 in the sub-region T12. Figure 2As shown, the width D111 of the guide pillar 211-1 located in the sub-region T11 may be greater than the width D121 of the guide pillar 212-1 located in the sub-region T12, and the width D112 of the guide pillar 211-2 located in the sub-region T11 may be greater than the width D122 of the guide pillar 212-2 located in the sub-region T12, but the embodiments of the present disclosure are not limited to this.

[0072] In some embodiments, the metastructure 20 further includes a plurality of guide pillars 213 located in the sub-region T13. Each guide pillar 213 may include the same or similar material as the guide pillar 211 or the guide pillar 212. Figure 2 As shown, the guide pillars 213 located in the sub-region T13 may have a pitch P13.

[0073] In some embodiments, two adjacent guide pillars 213 (e.g., guide pillar 213-1 and guide pillar 213-2) have a spacing P13, and the spacing P13 is greater than the spacing P12. Here, the spacing P13 can be defined as the distance from the central axis of one guide pillar 213 to the central axis of the adjacent guide pillar 213. Similarly, in a cross-section of the optical device 100 cut along the radiation direction R of the optical device 100 (e.g., Figure 2 In the cross-section of the optical device 100 shown in FIG, there are four guide pillars 213 in the sub-region T13, but the embodiment of the disclosure is not limited thereto.

[0074] In some embodiments, a cross section of the optical device 100 cut along the radiation direction R of the optical device 100 (eg, Figure 2 In the cross section of the optical device 100 shown in FIG. 1 , the sub-region T13 has a region width W13 , and the region width W13 is greater than the region width W12 .

[0075] In some embodiments, a cross section of the optical device 100 cut along the radiation direction R of the optical device 100 (eg, Figure 2 In the cross section of the optical device 100 shown in FIG. 1 , the guide pillars 213 in the sub-region T13 have different widths.

[0076] In some embodiments, as Figure 2 As shown, the guide pillar 213-1 in the sub-region T13 corresponds to the guide pillar 212-1 in the sub-region T12 (or the guide pillar 211-1 in the sub-region T11), and the guide pillar 213-2 in the sub-region T13 corresponds to the guide pillar 212-2 in the sub-region T12 (or the guide pillar 211-2 in the sub-region T11). The width D131 of the guide pillar 213-1 is greater than the width D132 of the guide pillar 213-2. In other words, the closer the guide pillar 213 is to the central region C, the larger its width.

[0077] In some embodiments, the width of the guide pillar 212 in the sub-region T12 is greater than the width of the corresponding guide pillar 213 in the sub-region T13. Figure 2 As shown, the width D121 of the guide pillar 212-1 located in the sub-region T12 may be greater than the width D131 of the guide pillar 213-1 located in the sub-region T13, and the width D122 of the guide pillar 212-2 located in the sub-region T12 may be greater than the width D132 of the guide pillar 213-2 located in the sub-region T13, but the embodiments of the present disclosure are not limited to this.

[0078] Reference Figure 2 In some embodiments, the optical device 100 further includes a protective layer 30, which is disposed on the substrate 10 and the metastructure 20 to protect the metastructure 20. Figure 2 As shown, the protection layer 30 may be disposed on and between the guide pillars 211 , 212 , and 213 of the metastructure 20 , but the embodiment of the disclosure is not limited thereto.

[0079] In some embodiments, the refractive index of the protective layer 30 is lower than the refractive indexes of the guide pillars 211, 212, and 213 of the metastructure 20. For example, the refractive index of the protective layer 30 may be between about 1.2 and about 1.7. The protective layer 30 may include an organic material (e.g., PMMA, PDMS, PMP), SiO2, MgO, Al2O3, GeO2, BeO, other suitable materials, or combinations thereof, but the present disclosure is not limited thereto.

[0080] In some other embodiments, the refractive index of the protective layer 30 is greater than the refractive index of the guide pillars 211, 212, and 213 of the metastructure 20. For example, the refractive index of the protective layer 30 may be between about 2.0 and about 5.2, and the protective layer 30 may include SiN, TiO2, SiH, GaN, HfO2, GaP, InP, GaSe, PbTe, PbSe, other suitable materials, or combinations thereof, but the embodiments of the present disclosure are not limited thereto.

[0081] Reference Figure 1 In some embodiments, the optical device 100 also has a second-type region T2 located between the central region C and the first-type region T1. For example, the second-type region T2 may be located at the edge (peripheral) region of the optical device 100 and adjacent to the first-type region T1.

[0082] In some embodiments, the second type region T2 includes multiple sub-regions. Figure 3As shown, the second type region T2 may include a sub-region T21 and a sub-region T22, with sub-region T22 located between the central region C and sub-region T21. However, the present disclosure is not limited to this. The number of sub-regions in the second type region T2 may be greater than sixty, for example, depending on actual needs or process limitations.

[0083] Reference Figure 3 In some embodiments, the metastructure 20 further includes a plurality of guide pillars 221 located in the sub-region T21 and a plurality of guide pillars 222 located in the sub-region T22. Figure 3 As shown, the guide pillars 221 located in the sub-region T21 may have a pitch P21, and the guide pillars 222 located in the sub-region T22 may have a pitch P22.

[0084] In some embodiments, two adjacent guide pillars 221 (e.g., guide pillar 221-1 and guide pillar 221-2) have a spacing P21, and two adjacent guide pillars 222 (e.g., guide pillar 222-1 and guide pillar 222-2) have a spacing P22, and spacing P22 is greater than spacing P21. Here, spacing P21 can be defined as the distance from the central axis of one guide pillar 221 to the central axis of an adjacent guide pillar 221. Similarly, spacing P22 can be defined as the distance from the central axis of one guide pillar 222 to the central axis of an adjacent guide pillar 222.

[0085] In some embodiments, a cross section of the optical device 100 cut along the radiation direction R of the optical device 100 (eg, Figure 3 In the cross section of the optical device 100 shown in FIG, the number of guide pillars in each sub-region of the second type region T2 is the same. In addition, in some embodiments, the number of guide pillars in each sub-region of the second type region T2 is greater than the number of guide pillars in each sub-region of the first type region T1. For example, Figure 3 As shown, there are five guide pillars 221 in the sub-region T21 and five guide pillars 222 in the sub-region T22 , but the embodiment of the present disclosure is not limited thereto.

[0086] In some embodiments, a cross section of the optical device 100 cut along the radiation direction R of the optical device 100 (eg, Figure 3 In the cross section of the optical device 100 shown in FIG. 1 , the sub-region T21 has a region width W21 , the sub-region T22 has a region width W22 , and the region width W22 is greater than the region width W21 .

[0087] In some embodiments, a cross section of the optical device 100 cut along the radiation direction R of the optical device 100 (eg, Figure 3In the cross section of the optical device 100 shown in FIG. 1 , the guide pillars 221 in the sub-region T21 have different widths, and the guide pillars 222 in the sub-region T22 have different widths.

[0088] In some embodiments, as Figure 3 As shown, guide pillar 221-1 is closer to sub-region T22 than guide pillar 221-2, and guide pillar 221-1 has a width D211 greater than guide pillar 221-2's width D212. That is, the closer the guide pillar 221 is to central region C (or sub-region T22), the wider it is.

[0089] In some embodiments, as Figure 3 As shown, the guide pillar 222-1 in the sub-region T22 corresponds to the guide pillar 221-1 in the sub-region T21, and the guide pillar 222-2 in the sub-region T22 corresponds to the guide pillar 221-2 in the sub-region T21. The width D221 of the guide pillar 222-1 is greater than the width D222 of the guide pillar 222-2. Similarly, the closer the guide pillar 222 is to the central region, the larger its width.

[0090] In some embodiments, the width of the guide pillar 221 in the sub-region T21 is greater than the width of the corresponding guide pillar 222 in the sub-region T22. Figure 3 As shown, the width D211 of the guide pillar 221-1 in the sub-region T21 may be greater than the width D221 of the guide pillar 222-1 in the sub-region T22, and the width D212 of the guide pillar 221-2 in the sub-region T21 may be greater than the width D222 of the guide pillar 222-2 in the sub-region T22, but the embodiments of the present disclosure are not limited thereto. In addition, in some embodiments, Figure 3 The guide pillar 221-1 shown has a width D211 greater than Figure 2 The guide pillar 211 - 1 has a width D111 , that is, the maximum width of the guide pillar 221 is greater than the maximum width of the guide pillar 211 .

[0091] Similarly, if Figure 3 As shown, the protection layer 30 may be disposed on and between the guide pillars 221 and 222 of the metastructure 20 , but the embodiment of the disclosure is not limited thereto.

[0092] In an embodiment of the present disclosure, in each sub-region of the first type region T1 and the second type region T2, different spacings between different sub-regions, region widths of different sub-regions, or different widths of guide pillars can be defined for a specific deflection angle of light, thereby effectively improving the light collection efficiency of the optical device.

[0093] Figure 4 FIG. 1 is a partial cross-sectional view of an optical device 102 according to another embodiment of the present disclosure. The top view of the optical device 102 may be similar to Figure 1 The optical device 100 shown. That is, Figure 4 It can be a partial cross-sectional view of the optical device cut along line AA', but the embodiments of the present disclosure are not limited thereto. Similarly, for the sake of simplicity, Figure 4 Some components of the optical device 102 may be omitted.

[0094] In some embodiments, the optical device 102 includes a substrate 10. The optical device 102 also includes a metastructure 20 disposed on the substrate 10. The metastructure 20 includes a plurality of guide pillars 211 located in a sub-region T11, a plurality of guide pillars 212 located in a sub-region T12, and a plurality of guide pillars 213 located in a sub-region T13. A cross-section of the optical device 102 taken along the radiation direction R of the optical device 102 (e.g., Figure 4 In the cross section of the optical device 102 shown in FIG, two adjacent guide pillars 211 have a spacing P11, two adjacent guide pillars 212 have a spacing P12, and two adjacent guide pillars 213 have a spacing P13. The spacing P13 is greater than the spacing P12, and the spacing P12 is greater than the spacing P11.

[0095] Reference Figure 4 In some embodiments, the optical device 102 further includes an anti-reflection layer 40 disposed on the metastructure 20. For example, the anti-reflection layer 40 may include an anti-reflection coating (ARC), a multilayer film, or a grating layer, but the present disclosure is not limited thereto.

[0096] In some embodiments, as Figure 4 As shown, the optical device 102 further includes a protective layer 30 disposed between the substrate 10 and the anti-reflection layer 40 to protect the metastructure 20. More specifically, the anti-reflection layer 40 can improve the transmittance at the interface between the protective layer 30 (eg, polymer) and air.

[0097] Figure 5 FIG. 1 is a partial cross-sectional view of an optical device 104 according to another embodiment of the present disclosure. The top view of the optical device 104 may be similar to Figure 1 The optical device 100 shown. That is, Figure 5 It can be a partial cross-sectional view of the optical device cut along line AA', but the embodiments of the present disclosure are not limited thereto. Similarly, for the sake of simplicity, Figure 5 Some components of the optical device 104 may be omitted.

[0098] In some embodiments, the height of each guide post in the second type region T2 is lower than the height of each guide post in the first type region T1. Figure 5As shown, the height H2 of each guide pillar 221' in the sub-region T21 of the second-type region T2 may be lower than the height H1 of each guide pillar 211 in the sub-region T11 of the first-type region T1 and each guide pillar 212 in the sub-region T12, but the present embodiment is not limited thereto. For example, the height H1 of each guide pillar 211 in the sub-region T11 of the first-type region T1 and each guide pillar 212 in the sub-region T12 may be in the range of approximately 0.5 μm to approximately 1.0 μm, but the present embodiment is not limited thereto.

[0099] Reference Figure 5 In some embodiments, light L perpendicularly entering the second-type region T2 (e.g., sub-region T21) deviates from the normal N of the optical device 104 by 15 degrees or less after passing through the second-type region T2. ​​In other words, the angle θ between the emitted light L' and the normal N of the optical device 104 may be within a range of 0 degrees to about 15 degrees, but the present disclosure is not limited thereto.

[0100] In the aforementioned embodiment, the metastructure 20 may include a plurality of guide pillars (not shown) located in the central region C, but the present disclosure is not limited thereto. In some other embodiments, a Fresnel lens is disposed adjacent to the metastructure 20, and the Fresnel lens is located in the central region C.

[0101] To sum up, in the embodiments of the present disclosure, in each sub-region of the first type region and the second type region, different spacings between different sub-regions, region widths of different sub-regions, or different widths of guide pillars can be defined for specific deflection angles of light, thereby effectively improving the light collection efficiency of the optical device.

[0102] The above summarizes the components of several embodiments so that those skilled in the art in the technical field to which the present disclosure belongs can better understand the viewpoints of the embodiments of the present disclosure. Those skilled in the art in the technical field to which the present disclosure belongs should understand that they can design or modify other processes and structures based on the embodiments of the present disclosure to achieve the same purposes and / or advantages as the embodiments introduced herein. Those skilled in the art in the technical field to which the present disclosure belongs should also understand that such equivalent structures do not deviate from the spirit and scope of the present disclosure, and they can make various changes, substitutions and replacements without violating the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure shall be as defined by the appended claims. In addition, although the present disclosure has been disclosed as above with several preferred embodiments, they are not intended to limit the present disclosure.

[0103] References throughout this specification to features, advantages, or similar language do not imply that all features and advantages that may be achieved with the present disclosure should or may be achieved in any single embodiment of the present disclosure. Rather, language referring to features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Thus, discussions of features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.

[0104] Furthermore, the described features, advantages, and characteristics of the present disclosure may be combined in any suitable manner in one or more embodiments. Based on the description herein, one skilled in the relevant art will recognize that the present disclosure may be practiced without one or more of the specific features or advantages of a particular embodiment. In other cases, additional features and advantages may be identified in certain embodiments that may not be present in all embodiments of the present disclosure.

Claims

1. An optical device having a central region and a first type region, the first type region surrounding the central region, wherein the first type region includes a first sub-region and a second sub-region, the second sub-region is between the central region and the first sub-region, and the optical device comprises: a substrate; as well as A metastructure is disposed on the substrate, wherein the metastructure comprises: A plurality of first guide pillars are located in the first sub-region; and A plurality of second guide pillars are located in the second sub-region, wherein in a cross section of the optical device cut along a radiation direction of the optical device, two adjacent ones of the plurality of first guide pillars have a first spacing, and two adjacent ones of the plurality of second guide pillars have a second spacing, and the second spacing is greater than the first spacing; Wherein, in a cross-section of the optical device cut along the radiation direction of the optical device, multiple first guide pillars have different widths, multiple second guide pillars have different widths, multiple first guide pillars include a first specific guide pillar and a second specific guide pillar adjacent to the first specific guide pillar, the first specific guide pillar is closer to the second sub-region than the second specific guide pillar, the width of the first specific guide pillar is greater than the width of the second specific guide pillar, multiple second guide pillars include a third specific guide pillar and a fourth specific guide pillar, the third specific guide pillar corresponds to the first specific guide pillar, the fourth specific guide pillar corresponds to the second specific guide pillar, the width of the third specific guide pillar is greater than the width of the fourth specific guide pillar, and the width of the third specific guide pillar is greater than the width of the first specific guide pillar.

2. An optical device as described in claim 1, wherein in a cross-section of the optical device cut along the radiation direction of the optical device, the number of the first guide pillars is the same as the number of the second guide pillars, and the number of the first guide pillars and the number of the second guide pillars are greater than or equal to four.

3. An optical device as described in claim 1, wherein in a cross-section of the optical device cut along the radiation direction of the optical device, the first sub-region has a first region width, the second sub-region has a second region width, and the second region width is greater than the first region width. 4 . The optical device as claimed in claim 1 , wherein a width of the fourth specific guide column is greater than a width of the second specific guide column.

5. The optical device as claimed in claim 1, wherein the optical device further comprises a second type region, the second type region is between the central region and the first type region, the second type region comprises a plurality of third sub-regions, and the metastructure further comprises: A plurality of third guide pillars are located in each of the third sub-regions, Wherein, in a cross section of the optical device cut along the radiation direction of the optical device, the number of the third guide pillars is greater than the number of the first guide pillars and the number of the second guide pillars.

6. The optical device as claimed in claim 1, wherein the optical device further comprises a second type region, the second type region is between the central region and the first type region, the second type region comprises a plurality of third sub-regions, and the metastructure further comprises: A plurality of third guide pillars are located in each of the third sub-regions, In a cross section of the optical device cut along the radiation direction of the optical device, the plurality of third guide pillars in each third sub-region have different widths.

7. The optical device as claimed in claim 1, wherein the optical device further comprises a second type region, the second type region is between the central region and the first type region, the second type region comprises a plurality of third sub-regions, and the metastructure further comprises: A plurality of third guide pillars are located in each of the third sub-regions, In a cross section of the optical device cut along the radiation direction of the optical device, a maximum width of the plurality of third guide pillars is greater than a maximum width of the plurality of first guide pillars.

8. The optical device as claimed in claim 1, wherein the optical device further comprises a second type region, the second type region is between the central region and the first type region, the second type region comprises a plurality of third sub-regions, and the metastructure further comprises: A plurality of third guide pillars are located in each of the third sub-regions, The height of each third guide pillar is lower than the height of each first guide pillar and the height of each second guide pillar, and the light vertically entering the second type area deviates from the normal of the optical device by 15 degrees or less after passing through the second type area.

9. The optical device of claim 1, further comprising: A Fresnel lens is disposed adjacent to the metastructure, wherein the Fresnel lens is located in the central region.

10. The optical device of claim 1, further comprising: an anti-reflection layer disposed on the metastructure; and A protective layer is disposed between the substrate and the anti-reflection layer.

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