Lens with layered extensions

Abstract

A lens having layered extensions is provided. The lens includes: a substrate; a first coating film disposed on the substrate and including a spacer layer dividing the first coating film into two layers; and a second coating film disposed on the first coating film and having a nanoporous structure (NPS).

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0063310, filed on May 14, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes. Technical Field

[0003] The following description relates to lenses. Background Technology

[0004] To reduce flare phenomena in multiple lenses, conventional low-reflection lenses with a reflectivity of less than about 0.5% can be fabricated by repeatedly depositing high-refractive-index and low-refractive-index thin films.

[0005] Furthermore, for ultra-low reflectivity lenses with reflectivity reduced to approximately 0.15% or lower, nanoporous structures (NPS) can be applied to further reduce flare phenomena.

[0006] Conventional antireflective coated lenses using NPS can have a structure of lens portion, silicon dioxide (SiO2) layer and aluminum oxide (Al2O3) layer, or a structure of lens portion, interlayer, SiO2 layer and Al2O3 layer, and each of these layers can be manufactured by depositing a thin film a few nanometers to tens of nanometers thick, and then immersing the deposited film in distilled water at 50°C to 100°C for 5 minutes or longer (hot water treatment (HWT) process) to transform the topmost Al2O3 layer into a nanostructure.

[0007] Furthermore, to verify the reliability of the manufactured lenses, they can be tested to withstand thermal shock at temperatures of approximately 100°C. However, during the HWT process or reliability assessment, cracks may appear due to stress between the films, which could then lead to an increase in the product defect rate. Summary of the Invention

[0008] This summary is provided to present the selection of concepts in a simplified form, while these concepts are further described in the following detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter.

[0009] In general, the lens includes: a substrate; a first coating film disposed on the substrate and including a separating layer dividing the first coating film into two layers; and a second coating film disposed on the first coating film and having a nanoporous structure (NPS).

[0010] The second coating film may have a gradient refractive index in which the refractive index increases from the upper end to the lower end of the second coating film.

[0011] The lens may also include an interlayer disposed between the substrate and the first coating film.

[0012] The first coating film may further include a first extended layer disposed on the upper side of the first coating film and a second extended layer disposed on the lower side of the first coating film, and the first extended layer and the second extended layer may be separated by a separator layer.

[0013] The separator layer can be formed to be thinner than the first extended layer.

[0014] The thickness of the first extended layer can be different from the thickness of the second extended layer.

[0015] The thickness of the first extended layer can be thinner than the thickness of the second extended layer.

[0016] The separator layer can have a higher refractive index than the first extended layer and the second extended layer.

[0017] The second coating film can have a higher refractive index than the first extended layer and the second extended layer.

[0018] The first extended layer and the second extended layer may each include at least one of silicon dioxide (SiO2), silicon-based mixed oxides and nitrides, and magnesium fluoride (MgF2).

[0019] The separator layer may include aluminum oxide (Al2O3).

[0020] The second coating film may include aluminum oxide (Al2O3).

[0021] In general, the lens includes: a substrate; an interlayer disposed on the upper surface of the substrate; a first coating film disposed on the interlayer and including a first extended layer, a second extended layer and a separating layer separating the first extended layer and the second extended layer; and a second coating film disposed on the first coating film and having a nanoporous structure (NPS).

[0022] The thickness of the first extended layer can be thinner than the thickness of the second extended layer.

[0023] Other features and aspects will become apparent from the following detailed description, drawings, and claims. Attached Figure Description

[0024] Figure 1 This is a schematic cross-sectional view illustrating a stacked structure of exemplary lenses according to one or more embodiments.

[0025] Figure 2This is a schematic cross-sectional view illustrating a stacked structure of exemplary lenses according to one or more embodiments.

[0026] Figure 3 This is a schematic cross-sectional view showing the stacked structure of a conventional lens (Comparative Example 1).

[0027] Figure 4 This is a cross-sectional view schematically showing the stacked structure of a conventional lens (Comparative Example 2).

[0028] Figure 5 This is a graph comparing the reflectance of Comparative Example 1, Comparative Example 2, and the reflectance of the exemplary embodiment.

[0029] Throughout the accompanying drawings and detailed embodiments, the same reference numerals denote the same elements unless otherwise described. For clarity, illustration, and convenience, the drawings may not be drawn to scale, and the relative dimensions, scale, and depiction of elements in the drawings may be exaggerated. Detailed Implementation

[0030] The following detailed embodiments are provided to help the reader gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations and / or the order within operations described herein are merely examples and are not limited to the order set forth herein, but can be changed as will be apparent after understanding the disclosure of this application, except for the order of operations and / or the order within operations that must occur in a certain order. As another example, the order of operations and / or the order within operations can be performed in parallel, except for at least a portion of the order of operations and / or at least a portion of the order within operations that must occur in a certain order (e.g., a specific order). Furthermore, for clarity and brevity, descriptions of features known after understanding the disclosure of this application may be omitted.

[0031] Although terms such as “first,” “second,” and “third,” or A, B, (a), (b), etc., may be used herein to describe various components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts are not limited by these terms. Each of these terms is not intended to define, for example, the nature, order, or sequence of the corresponding component, assembly, region, layer, or part, but only to distinguish the corresponding component, assembly, region, layer, or part from other components, assemblies, regions, layers, or parts. Therefore, the first component, first assembly, first region, first layer, or first part mentioned in the examples described herein may also be referred to as a second component, second assembly, second region, second layer, or second part without departing from the teachings of the examples.

[0032] Throughout this specification, when a component, element, or layer is described as being “on,” “connected to,” “attached to,” or “joined to” another component, element, or layer, it may be directly “on” (e.g., in contact with), directly “connected to,” directly “attached to,” or directly “joined to” the other component, element, or layer, or one or more other components, elements, or layers may reasonably be present between them. When a component, element, or layer is described as being “directly” “on,” “directly connected to,” “directly attached to,” or “directly joined to” another component, element, or layer, there are no other components, elements, or layers between them. Similarly, expressions such as “between” and “immediately between” and “adjacent to” and “immediately adjacent to” can also be interpreted as described above.

[0033] The terminology used herein is for describing various examples only and is not intended to limit this disclosure. The terms “a,” “an,” and “the” are intended to include the plural meaning as well, unless the context clearly indicates otherwise. As a non-limiting example, the terms “comprising,” “including,” and “having” specify the presence of the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof, nor do they exclude the alternative presence of features, quantities, operations, components, elements, and / or combinations thereof. Furthermore, while one embodiment may describe the presence of such terms “comprising,” “including,” and “having” specifying the presence of the stated features, quantities, operations, components, elements, and / or combinations thereof, other embodiments may exist in which one or more of the stated features, quantities, operations, components, elements, and / or combinations thereof are absent.

[0034] As used herein, the term “and / or” includes any one of the associated listed items and any combination of any two or more of the associated listed items. The phrases “at least one of A, B, and C” are intended to have a separate meaning, and these phrases also include examples in which one or more of A, B, and C may be present (e.g., any combination of one or more of A, B, and C), unless the corresponding description and implementation require that such an enumeration (e.g., “at least one of A, B, and C”) be interpreted as having a combined meaning.

[0035] The features described herein may be implemented in various forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided merely to illustrate some of the many possible ways in which the methods, apparatus, and / or systems described herein will be apparent upon understanding the disclosure of this application. In this document, the term “may” (e.g., regarding what an example or implementation may include or implement) is used with respect to an example or implementation, meaning that there exists at least one example or implementation that includes or implements this feature, and that all examples and implementations are not limited thereto. The terms “example” or “implementation” as used herein have the same meaning (e.g., the phrase “in one example” has the same meaning as “in one implementation,” and “in one or more examples” has the same meaning as “in one or more implementations”).

[0036] One or more examples may provide a lens in which a separating layer is provided, such that in a low-reflection lens applying a nanoporous structure (NPS), the first coating film that extends the anti-reflection bandwidth is divided into two layers, thereby reducing reflectivity and the incidence of cracking.

[0037] One or more examples can provide a lens that reduces the incidence of cracking while improving anti-reflective properties.

[0038] Figure 1 This is a schematic cross-sectional view illustrating a stacked structure of exemplary lenses according to one or more embodiments.

[0039] Reference Figure 1 The lens 100 according to one or more embodiments may include a substrate 110, a first coating film 200 and a second coating film 130.

[0040] The shape or type of substrate 110 is not particularly limited, and substrate 110 can be implemented in a lens that can be used in optical devices (such as, but not limited to, camera modules).

[0041] In a non-limiting example, the substrate 110 may be formed of a material such as a polymer, and may be formed of, for example, a plastic resin including a resin component.

[0042] The first coating film 200 can be disposed on the upper side of the substrate 110 to reduce the reflectivity of the surface of the substrate 110, and can act as (or) an extension to further widen the anti-reflection bandwidth, thereby reducing or preventing flare phenomena.

[0043] The first coating film 200 may have a separator layer 230 disposed in the middle portion in the vertical direction, such that the extended portion can be divided into two layers as an upper layer and a lower layer.

[0044] In this example, the layer positioned above the separator layer 230 can be referred to as the first extension layer 220, and the layer positioned below the separator layer 230 can be referred to as the second extension layer 210.

[0045] When the first coating film 200 is divided into a first extended layer 220 and a second extended layer 210 in this manner, the stress caused by the thickness difference between the films can be reduced, thereby reducing the incidence of cracks.

[0046] In this example, the corresponding first extended layer 220 and second extended layer 210 may include at least one of SiO2, Si-based mixed oxides and nitrides, magnesium fluoride (MgF2), etc.

[0047] Si-based mixed oxides or nitrides can be SiN x SiAl x O y SiAl x O y N z wait.

[0048] Additionally, in the example, the corresponding first extension layer 220 and second extension layer 210 may have different thicknesses, and in a non-limiting example, the thickness of the first extension layer 220 may be formed to be thinner than the thickness of the second extension layer 210.

[0049] The separator layer 230 may be formed of a material having a higher refractive index than the main material included in the respective first extension layer 220 and second extension layer 210.

[0050] In the example, when the corresponding first extended layer 220 and second extended layer 210 include SiO2, the separator layer 230 may include Al2O3 having a higher refractive index than SiO2.

[0051] When a separator layer 230, which can have a relatively higher refractive index than the corresponding first extended layer 220 and second extended layer 210, is provided between the first extended layer 220 and the second extended layer 210, the gradient refractive index and the anti-reflection effect of high refractive index / low refractive index can be combined, so that a better effect of reducing reflectivity can be expected compared with a coating film that only applies gradient refractive index.

[0052] In this example, the separator layer 230 can be formed to be thinner than the first extended layer 220. The main function of the separator layer 230 may be to reduce or prevent stress in adjacent layers due to excessive thickness of the first coating film 200, and when the separator layer 230 is thicker than the first extended layer 220, problems such as reduced overall productivity and weakened anti-reflective effect due to delay in deposition time may occur.

[0053] The second coating film 130 can be disposed on the upper side of the first coating film 200, and in this example, it can be disposed on the upper side of the first extended layer 220.

[0054] In the example, the second coating film 130 can be formed as a nanoporous structure (NPS).

[0055] The second coating film 130 may have a gradient refractive index, wherein the refractive index of the portion in contact with air is close to 1, and the refractive index gradually increases toward the first coating film 200 on the lower side.

[0056] The second coating film 130 can have an anti-reflective effect to further reduce the reflectivity of the lens 100.

[0057] The second coating film 130 may be formed of a material having a higher refractive index than the corresponding first extended layer 220 and second extended layer 210.

[0058] In the example, when the corresponding first extended layer 220 and second extended layer 210 include SiO2, the second coating film 130 may include Al2O3 having a higher refractive index than SiO2.

[0059] When the first coating film 200 is formed too thickly on the lens, the stress on the substrate may increase, which may increase the incidence of cracks.

[0060] In the example, the first coating film 200 can be divided into a first extended layer 220 and a second extended layer 210 with thin thicknesses to reduce stress between the films, thereby reducing the incidence of cracks.

[0061] Figure 2 This is a schematic cross-sectional view illustrating a stacked structure of exemplary lenses according to one or more embodiments.

[0062] Reference Figure 2 An exemplary lens 101 according to one or more embodiments may further include an interlayer 120 disposed between a substrate 110 and a first coating film 200.

[0063] The interlayer 120 can be a bonding layer for bonding the substrate 110 and the first coating film 200, and can also eliminate the delamination phenomenon between the substrate 110 and the first coating film 200.

[0064] In this example, the interlayer 120 can be formed to be thinner than the first coating film 200. Since the interlayer 120 is designed to prevent delamination that may occur when the adhesive strength between the substrate 110 and the first coating film 200 is low, the interlayer 120 can be formed at a minimum thickness without delamination.

[0065] Additionally, in the example, the interlayer 120 can be formed to be thicker than the first extended layer 220 and thinner than the second extended layer 210.

[0066] Additionally, in this example, the interlayer 120 can be formed to be thinner than the second coating film 130.

[0067] Typically, when the interlayer is placed between the substrate and the first coating film, the reflectivity may increase slightly, and the incidence of cracks may also increase.

[0068] According to the embodiment, a separating layer 230 can be applied to divide the first coating film 200 into corresponding first extended layer 220 and second extended layer 210, thereby achieving a low-reflection coating structure that simultaneously achieves NPS and high refractive index / low refractive index anti-reflection effects. At the same time, compared with the interlayer in a conventional thin film structure, the first coating film 200, which is formed to be too thick, can be divided into corresponding first extended layer 220 and second extended layer 210 with thin thickness, thereby reducing the stress between the films and thus reducing the cracking rate.

[0069] <Experimental Example>

[0070] Figure 3 This is a schematic cross-sectional view showing the stacked structure of a conventional lens (Comparative Example 1).

[0071] Figure 3 Comparison Example 1 is shown, and Figure 3 The lens 100' shown is a lens with a conventional ultra-low reflection NPS coating structure and has the following structure: a sandwich layer 120 is disposed on a substrate 110, a first coating film 200' as a single layer is disposed on the sandwich layer 120, and a second coating film 130 is disposed on the first coating film 200'.

[0072] The substrate 110 is formed as a polymer lens portion, the interlayer 120 includes Al2O3, and the first coating film 200' includes SiO2 and has a thickness of about 5 times that of the interlayer 120. The second coating film 130 has NPS and includes Al2O3.

[0073] In Comparative Example 1, interlayer 120 has a thickness of 18.4 nm, first coating film 200' has a thickness of 101.9 nm, and second coating film 130 has a thickness of 41.3 nm.

[0074] These thicknesses can be measured using both non-destructive and destructive testing. Examples of non-destructive testing include ellipsometers, reflectometers, and processes using atomic force microscopy.

[0075] As an example of destructive testing, each layer of the interlayer 120, the first coating film 200', and the second coating film 130 can be subjected to focused ion beam (FIB) cross-section treatment followed by transmission electron microscopy (TEM) analysis, and the components can also be analyzed by EDS analysis. Furthermore, analyses can be performed using FT-IR, XPS, etc.

[0076] Each of these layers can be sectioned to include the central portion of the lens, i.e., the thickest area of ​​the lens.

[0077] The thickness of each of these layers can be defined as a distance measured in a direction perpendicular to its surface, and can be determined as the average of multiple values ​​measured in multiple equally spaced regions.

[0078] Figure 4 This is a cross-sectional view schematically showing the stacked structure of a conventional lens (Comparative Example 2).

[0079] Figure 4 Comparison Example 2 is shown, and Figure 4 The lens 100” shown has the following structure: a sandwich layer 120 is disposed on the substrate 110, a first coating film 200” is disposed on the sandwich layer 120, and a second coating film 130 is disposed on the first coating film 200”.

[0080] The substrate 110 is formed as a polymer lens portion, the interlayer 120 includes Al2O3, and the first coating film 200" includes SiO2 and has a thickness of about 4 times that of the interlayer 120. The second coating film 130 has NPS and includes Al2O3.

[0081] In Comparative Example 2, in the same manner as Comparative Example 1, interlayer 120 has a thickness of 18.4 nm, first coating film 200” has a thickness of 73.1 nm, and in the same manner as Comparative Example 1, second coating film 130 has a thickness of 41.3 nm.

[0082] In other words, Comparative Example 2 has a similar structure to Comparative Example 1, but the thickness of the first coating film 200” is formed to be thinner than that of the first coating film 200' in Comparative Example 1, in order to improve the defect rate due to the occurrence of cracks.

[0083] Figure 2 An exemplary implementation is shown. Figure 2The lens 101 shown has the following structure: a sandwich layer 120 is disposed on a substrate 110, a first coating film 200 is disposed on the sandwich layer 120, a second coating film 130 is disposed on the first coating film 200, and the first coating film 200 is divided by a separating layer 230 into a second extension layer 210 disposed on the lower side of the separating layer 230 and a first extension layer 220 disposed on the upper side of the separating layer 230.

[0084] The substrate 110 is formed as a polymer lens portion, the interlayer 120 includes Al2O3, the corresponding first extension layer 220 and second extension layer 210 of the first coating film 200 include SiO2, and the second coating film 130 may include NPS and Al2O3.

[0085] In the exemplary embodiment, in the same manner as Comparative Example 1 and Comparative Example 2, the interlayer 120 may have a thickness of 18.4 nm, and in the same manner as Comparative Example 1 and Comparative Example 2, the second coating film 130 may have a thickness of 41.3 nm.

[0086] The first extension layer 220 may have a thickness of 16.7 nm, the second extension layer 210 may have a thickness of 40.8 nm, and the separator layer 230 may have a thickness of 5.7 nm.

[0087] In the following text, a high-temperature reliability assessment was performed for 2 hours at 120°C using lenses from Comparative Example 1, Comparative Example 2, and the exemplary embodiment, and the number of cracks and crack incidence rate were measured before and after the assessment, as shown in Table 1 below.

[0088] Table 1:

[0089]

[0090] As shown in Table 1, in Comparative Example 1, cracks appeared in 173 out of a total of 432 products before the high-temperature reliability assessment, indicating a crack incidence rate of 40.0%, and cracks appeared in all products after the high-temperature reliability assessment.

[0091] In Comparative Example 2, where the thickness of the first coating film is relatively thinner than that of Comparative Example 1, cracks appeared in 66 out of a total of 432 products before the high-temperature reliability assessment, a reduction to a crack incidence rate of 15.3% compared to Comparative Example 1. However, after the high-temperature reliability assessment, as in Comparative Example 1, cracks appeared in all products.

[0092] Furthermore, as in Comparative Example 2, the reflectivity also increases slightly when the thickness of the first coating film decreases.

[0093] In other words, it can be seen that simply reducing the thickness of the first coating film may not improve the crack incidence rate after high-temperature reliability assessment, but may instead further increase the reflectivity problem.

[0094] In an exemplary embodiment, a separator layer 230 is inserted in the middle portion of the first coating film 200 to divide the first coating film 200 into a first extended layer 220 and a second extended layer 210, such that, compared with Comparative Example 1, the thickness of the first extended layer 220, the separator layer 230 and the second extended layer 210, excluding the second coating film 130, is significantly reduced, thereby reducing the stress between the films.

[0095] In particular, the thickness of the second extended layer 210 adjacent to the interlayer 120 is 40.8 nm, which can be significantly reduced to about half the thickness of Comparative Example 2.

[0096] Therefore, compared with Comparative Example 1 and Comparative Example 2, not only was the crack incidence rate significantly reduced to 7.6% before the high-temperature reliability assessment, but the crack incidence rate after the high-temperature reliability assessment was also significantly reduced to 7.6%, which is the same as before the high-temperature reliability assessment, indicating that it is also effective in preventing cracks caused by thermal shock.

[0097] Figure 5 This is a graph comparing the reflectance of Comparative Example 1, Comparative Example 2, and the reflectance of the exemplary embodiment.

[0098] Reference Figure 5 The average reflectance of Comparative Example 1 is 0.08%, the average reflectance of Comparative Example 2 is 0.06%, and the average reflectance of the Exemplary Embodiment is 0.04%, which confirms that the reflectance of the Exemplary Embodiment is the lowest. The reflectance is the average reflectance in the range of 380 nm to 780 nm.

[0099] Furthermore, according to one or more embodiments, the total thickness of the portion deposited on the lens portion can be reduced. As a standard prior to high-temperature reliability evaluation, the total thickness deposited in Comparative Example 1 was 161.6 nm, the total thickness deposited in Comparative Example 2 was 132.8 nm, and the total thickness deposited in the exemplary embodiment was 122.9 nm, representing a reduction in total thickness compared to Comparative Example 1 and Comparative Example 2. Therefore, a cost reduction effect can be expected in the exemplary embodiment compared to a conventional lens.

[0100] In this example, each layer can be formed by using a deposition method of atomic layer deposition (ALD) process, and if the total deposition time of Comparative Example 1 is 100%, then it is 90% in Comparative Example 2 and 80% in the exemplary embodiment, so that the manufacturing cycle can be shortened and the manufacturing cost can be further reduced according to the embodiment compared with conventional structures.

[0101] Based on one or more examples, it is possible to reduce the reflectivity and cracking rate of a lens.

[0102] While this disclosure includes specific examples, it will be apparent upon understanding the disclosure of this application that various changes in form and detail may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered descriptive only and not for limiting purposes. The description of features or aspects in each example is to be applied to similar features or aspects in other examples. Suitable results may also be obtained if the described techniques are performed in a different order, and / or if components in the described system, architecture, device, or circuit are combined in a different manner and / or replaced or supplemented by other components or their equivalents.

[0103] Therefore, in addition to the disclosure above and in all the accompanying drawings, the scope of this disclosure also includes the claims and their equivalents, that is, all variations within the scope of the claims and their equivalents should be interpreted as being included in this disclosure.

Claims

1. A lens, comprising: substrate; A first coating film is disposed on the substrate and includes a separator layer that divides the first coating film into two layers; as well as The second coating film, disposed on the first coating film, has a gradient refractive index and a nanoporous structure.

2. The lens according to claim 1, wherein, The second coating film has a gradient refractive index that increases from the upper end to the lower end of the second coating film.

3. The lens according to claim 1 further includes an interlayer disposed between the substrate and the first coating film.

4. The lens according to claim 1, wherein, The first coating film further includes a first extended layer disposed on the upper side of the first coating film and a second extended layer disposed on the lower side of the first coating film, and The first extended layer and the second extended layer are separated by the separating layer.

5. The lens according to claim 4, wherein, The separating layer is thinner than the first extended layer.

6. The lens according to claim 4, wherein, The thickness of the first extended layer is different from the thickness of the second extended layer.

7. The lens according to claim 4, wherein, The thickness of the first extended layer is thinner than the thickness of the second extended layer.

8. The lens according to claim 4, wherein, The separator layer has a higher refractive index than both the first extended layer and the second extended layer.

9. The lens according to claim 4, wherein, The second coating film has a higher refractive index than both the first extended layer and the second extended layer.

10. The lens according to claim 4, wherein, The first extended layer and the second extended layer each comprise at least one of silicon dioxide, silicon-based mixed oxide and nitride, and magnesium fluoride.

11. The lens according to claim 10, wherein, The separator layer comprises aluminum oxide.

12. The lens according to claim 10, wherein, The second coating film comprises aluminum oxide.

13. A lens, comprising: substrate; A sandwich layer is disposed on the upper surface of the substrate; A first coating film is disposed on the interlayer and includes a first extended layer, a second extended layer, and a separating layer that separates the first extended layer and the second extended layer; as well as The second coating film, disposed on the first coating film, has a gradient refractive index and a nanoporous structure.

14. The lens according to claim 13, wherein, The thickness of the first extended layer is thinner than the thickness of the second extended layer.

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