Lens element and electronic device

Abstract

To provide a lens element that offers desired optical performance.SOLUTION: A lens element according to one embodiment comprises an underlayer, multiple lenses arranged on the underlayer, lens protection layers made of a transparent inorganic material and arranged to cover respective multiple lenses, and an overcoat layer having a lower refractive index than each of the multiple lenses and covering the lens protection layers.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD Embodiments of the present invention relate to a lens element and an electronic device. [Background technology]

[0002] In recent years, combinations of microlenses with various elements have been proposed. One example of such combinations is a technique of combining a solid-state photoelectric conversion element with a microlens in order to improve the sensitivity of the solid-state imaging element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-307090 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a lens element and an electronic device that can achieve desired optical performance. [Means for solving the problem]

[0005] According to one embodiment, the lens element comprises an underlayer, a plurality of lenses arranged on the underlayer, a lens protection layer covering each of the plurality of lenses and formed of a transparent inorganic material, and an overcoat layer covering the lens protection layer and having a refractive index lower than that of each of the plurality of lenses.

[0006] According to one embodiment, an electronic device includes the lens element described above, a substrate, and a light-emitting element disposed between the lens element and the substrate.

[0007] According to one embodiment, an electronic device comprises the lens element described above, a substrate, and a light sensor disposed between the lens element and the substrate. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic plan view of a lens element 1 according to an embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of the lens element 1 according to the first embodiment taken along line VV in FIG. [Figure 3] FIG. 3 is a schematic cross-sectional view of the lens element 1 according to the second embodiment taken along line VV in FIG. [Figure 4] FIG. 4 is a diagram illustrating a method for manufacturing the lens element 1. [Figure 5] FIG. 5 is a diagram illustrating a method for manufacturing the lens element 1. [Figure 6] FIG. 6 is a schematic cross-sectional view showing an electronic device 2 according to the third embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view showing an electronic device 3 according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment will be described with reference to the drawings. The disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily make while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual embodiment for the sake of clarity, but these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification and each drawing, components that perform the same or similar functions as those described above with reference to the previous drawings are designated by the same reference numerals, and redundant detailed descriptions may be omitted as appropriate.

[0010] In the drawings, mutually perpendicular X, Y, and Z axes are shown as necessary to facilitate understanding. The direction along the X axis is referred to as the first direction X, the direction along the Y axis is referred to as the second direction Y, and the direction along the Z axis is referred to as the third direction Z. Viewing various elements parallel to the third direction Z is referred to as a planar view.

[0011] FIG. 1 is a schematic plan view of a lens element 1 according to an embodiment.

[0012] The lens element 1 includes an underlayer 15, a plurality of lenses LN, a lens protective layer LNP, and an overcoat layer OC.

[0013] In this embodiment, the shape of the underlayer 15 in plan view is not limited to a rectangle, but may be any other shape such as a square or other polygon, a circle, or an ellipse.

[0014] The base layer 15 is a transparent organic insulating layer and is formed using a resin material such as an acrylic resin, an epoxy resin, a polyimide resin, etc. The base layer 15 may also be a transparent inorganic insulating layer, a glass substrate, a resin substrate, etc.

[0015] The lenses LN are arranged at predetermined intervals in the first direction X and the second direction Y. Each of the lenses LN is arranged so as to overlap various elements 10, which will be described later. For example, the layout of the lenses LN is set in accordance with the layout of the elements 10. The pitch between adjacent lenses LN is equal to the pitch between adjacent elements 10.

[0016] In the illustrated example, the lens LN has an elliptical shape in plan view, with a width a in the first direction X being longer than a width b in the second direction Y. The shape of the lens LN is not limited to the illustrated example, and may be an elliptical shape in which the width a is shorter than the width b, or a circle in which the widths a and b are the same. The shape of the lens LN can be changed as appropriate to match the shape of the element 10 to be superimposed.

[0017] The lens LN can be formed using various transparent resin materials such as acrylic resin. From the viewpoint of suppressing undesired reflection and refraction at the interface between the base layer 15 and the lens LN, it is desirable that the lens LN be formed from a material having the same refractive index as the base layer 15. The base layer 15 may be formed from the same material as the lens LN, in which case the base layer 15 and the lens LN may be formed integrally.

[0018] The lens LN is covered with a lens protective layer LNP, which is covered with an overcoat layer OC. The lens protective layer LNP and the overcoat layer OC will be described in detail with reference to FIG.

[0019] The element 10 is covered with a base layer 15. The element 10 is, for example, a light emitting element LD or an optical sensor PD. By combining the lens element 1 with the light emitting element LD, which is an example of the element 10, an electronic device 2 can be configured. Furthermore, by combining the lens element 1 with the optical sensor PD, which is an example of the element 10, an electronic device 3 can be configured. Details will be described later.

[0020] [First embodiment] FIG. 2 is a schematic cross-sectional view of the lens element 1 according to the first embodiment taken along line VV in FIG.

[0021] The lenses LN are disposed on the underlayer 15 and are arranged at intervals in the first direction X. Each of the lenses LN is a convex lens. In the illustrated example, the lenses LN are aspherical lenses, but they may also be spherical lenses or cylindrical lenses.

[0022] The thickness T1 of the lens LN is not particularly limited. Here, the thickness T1 corresponds to the length along the third direction Z from the upper surface 15A of the base layer 15 (or the interface between the base layer 15 and the lens LN) to the vertex of the lens LN.

[0023] The lens protection layer LNP covers each of the lenses LN. In the example shown in Fig. 2, the lens protection layer LNP covers each of the lenses LN individually, and the upper surface 15A of the base layer 15 is exposed between adjacent lenses LN.

[0024] The lens protection layer LNP is made of a transparent inorganic material, for example, silicon nitride.

[0025] The lens protection layer LNP is formed with a substantially uniform thickness. At the apex of the lens LN, the thickness T2 of the lens protection layer LNP is smaller than the thickness T1 of the lens LN, and is, for example, 300 nm or less.

[0026] The overcoat layer OC overlaps the multiple lenses LN and covers the lens protective layer LNP. In the example shown in Fig. 2, the overcoat layer OC covers the base layer 15 between adjacent lenses LN. The overcoat layer OC also functions as a planarizing film that flattens the unevenness caused by the multiple lenses LN and the lens protective layer LNP.

[0027] The overcoat layer OC is a transparent organic insulating layer made of a material having a lower refractive index than the lens LN. For example, the overcoat layer OC can be made of a resin material such as an acrylic resin, an epoxy resin, or a polyimide resin.

[0028] The lens LN is formed using a photosensitive resin material. If the resin material has low cross-linking properties when the lens LN is formed, and the resin material for forming the overcoat layer OC is applied directly onto the lens LN, the resin material constituting the lens LN will dissolve in the resin material for forming the overcoat layer OC. If the resin material constituting the lens LN dissolves, the lens LN will not be formed in the desired shape, and optical performance may be reduced due to changes in refractive index and the generation of haze.

[0029] Therefore, in this embodiment, each lens LN is covered with a lens protective layer LNP made of a transparent inorganic material (silicon nitride). That is, the lens protective layer LNP is interposed between the lens LN and the overcoat layer OC. For this reason, the overcoat layer OC does not come into direct contact with the lens LN. Therefore, the resin material used to form the overcoat layer OC does not come into contact with the lens LN, and dissolution of the lens LN can be suppressed. In other words, deformation of the lens LN can be suppressed before and after the process of forming the overcoat layer OC. As a result, changes in refractive index and the occurrence of haze are suppressed, and desired optical performance can be obtained.

[0030] In particular, silicon nitride has a dense and uniform structure and also has high chemical stability, making it suitable as a material for forming the lens protective layer LNP.

[0031] The thickness T2 of the lens protective layer LNP is preferably as thin as possible so long as it can sufficiently prevent the lens LN from dissolving when the overcoat layer OC is formed, and is, for example, 50 nm or more. Furthermore, if the thickness T2 of the lens protective layer LNP exceeds 300 nm, there is a risk of a decrease in yield or a decrease in optical properties. Therefore, the thickness of the lens protective layer LNP is preferably 50 nm or more and 300 nm or less.

[0032] In one example, the underlayer 15, the lens LN, and the lens protective layer LNP have substantially the same refractive index, and the overcoat layer OC has a refractive index smaller than those of the underlayer 15, the lens LN, and the lens protective layer LNP.

[0033] As will be described later, the lens element 1 may have an optical film 16 on the overcoat layer OC. As the optical film, for example, a polarizing plate can be used.

[0034] [Second embodiment] FIG. 3 is a schematic cross-sectional view of the lens element 1 according to the second embodiment taken along line VV in FIG.

[0035] The lens element 1 shown in Fig. 3 differs from the lens element 1 shown in Fig. 2 in that a lens protective layer LNP covers the base layer 15 between multiple lenses LN. The overcoat layer OC is spaced apart from the base layer 15 between adjacent lenses LN. The rest of the configuration is the same as that of the lens element 1 shown in Fig. 2, and a description thereof will be omitted.

[0036] The second embodiment shown in Fig. 3 also provides the same effects as the first embodiment shown in Fig. 2. In addition, the process of individually patterning the lens protection layer LNP is not required, which simplifies the manufacturing process.

[0037] Next, a method for manufacturing the lens element 1 will be described with reference to FIGS.

[0038] 4, a lens material LNM for forming the lenses LN is applied onto the underlayer 15 (first step S1). The lens material LNM is, for example, a negative resin material.

[0039] After the first step S1, a mask MK having an opening of a predetermined shape is placed on the lens material LNM, as shown in the middle of Fig. 4. Thereafter, light (e.g., ultraviolet light) L1 is irradiated through the mask MK to expose the lens material LNM (second step S2).

[0040] Following the second step S2, the lens material LNM is developed (third step S3), as shown in the lower part of Fig. 4. In the illustrated example, the areas of the lens material LNM that have been exposed to the light L1 remain, and the areas that have been shielded by the mask MK are removed.

[0041] Subsequently, as shown in the upper part of FIG. 5, the remaining lens material LNM is baked, and the lens material LNM is reflowed to form a convex lens LN (fourth step S4).

[0042] After the fourth step S4, a lens protection layer LNP is formed (fifth step S5), as shown in the middle of FIG. 5. The lens protection layer LNP is formed by depositing silicon nitride, for example, by CVD (Chemical Vapor Deposition). The lens protection layer LNP formed in this manner uniformly covers the base layer 15 and the lenses LN. In the illustrated example, after the lens protection layer LNP is formed, the lens protection layer LNP is patterned. As a result, the lens protection layer LNP covers each lens LN individually and exposes the base layer 15 between adjacent lenses LN. Note that patterning of the lens protection layer LNP may be omitted.

[0043] Following the fifth step S5, an overcoat layer OC is formed (sixth step S6), as shown in the lower part of FIG. 5. The overcoat layer OC is formed by applying a resin material onto the lens protective layer LNP and curing the resin material. At this time, the lens LN is covered with the lens protective layer LNP and does not come into contact with the resin material used to form the overcoat layer OC. In this way, a lens LN having a desired shape is formed, and a lens element 1 having desired optical performance is manufactured.

[0044] Next, an electronic device to which the above lens element 1 is applied will be described. [Third embodiment] FIG. 6 is a schematic cross-sectional view of an electronic device 2 according to the third embodiment.

[0045] The electronic device 2 includes a substrate 11, a circuit layer 12, a partition wall 13, a light-emitting element LD, a sealing layer 14, a color filter CF, a lens element 1, and an optical film 16.

[0046] The substrate 11 may be glass or a flexible resin film.

[0047] The circuit layer 12 is disposed on the substrate 11. The circuit layer 12 includes, for example, various circuits such as pixel circuits, various wirings such as scanning lines, signal lines, and power supply lines, and various insulating layers.

[0048] The light emitting element LD is, for example, an organic EL element, and includes a lower electrode LE, an organic layer OR, and an upper electrode UE. Note that the light emitting element LD is not limited to an organic EL element, and may be other light emitting elements such as a micro LED or a mini LED.

[0049] The lower electrode LE is disposed on the circuit layer 12 and is electrically connected to a pixel circuit (not shown). The lower electrode LE is a multilayer structure including a transparent layer made of an oxide conductive material such as indium tin oxide (ITO) and a reflective layer made of a metal material such as silver.

[0050] The organic layer OR is disposed on the lower electrode LE. The organic layer OR includes an emitting layer and various functional layers such as a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0051] The partition wall 13 is formed so as to surround the lower electrode LE and the organic layer OR. The partition wall 13 can be made of an inorganic insulating material or an organic insulating material.

[0052] The upper electrode UE is disposed on the organic layer OR and the partition wall 13. The upper electrode UE is electrically connected to a power supply line (not shown) and is set to, for example, a common potential. The upper electrode UE is formed of, for example, a metal material such as an alloy of magnesium and silver (MgAg).

[0053] The sealing layer 14 is disposed so as to cover the upper electrode UE. The sealing layer 14 is formed as an inorganic insulating layer made of, for example, silicon nitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiON), or the like. Note that the sealing layer 14 may include an organic insulating layer in addition to the inorganic insulating layer.

[0054] The color filter CF is located directly above the light-emitting element LD in the third direction Z, and is disposed on the sealing layer 14. Note that the color filter CF may be omitted.

[0055] The lens element 1 is formed on the color filter CF. In other words, the light-emitting element LD is disposed between the substrate 11 and the lens element 1, and the color filter CF is disposed between the light-emitting element LD and the lens element 1. In the illustrated example, the base layer 15 of the lens element 1 covers the color filter CF. The lens LN is disposed directly above the light-emitting element LD and the color filter CF.

[0056] The optical film 16 is disposed on the overcoat layer OC of the lens element 1. For example, a polarizing plate can be used as the optical film 16. The optical film 16 may be omitted.

[0057] According to the third embodiment, by combining the lens element 1 and the light emitting element LD, internal reflection of the light L2 emitted from the light emitting element LD in the electronic device 2 is suppressed, and the light L2 that reaches the base layer 15 is extracted by the lens LN and contributes to display. Therefore, the extraction efficiency of the light L2 is improved, power saving is possible, and the front brightness can be improved.

[0058] [Fourth embodiment] FIG. 7 is a schematic cross-sectional view of the electronic device 3 according to the fourth embodiment taken along line VV in FIG.

[0059] The electronic device 3 includes a substrate 11, a circuit layer 12, a photosensor PD, a lens element 1, and an optical film 16. Note that the optical film 16 may be omitted.

[0060] A circuit layer 12 is disposed on the substrate 11 .

[0061] The optical sensor PD is disposed on the circuit layer 12. The optical sensor PD has a function of detecting, for example, light L3 incident from the top surface of the electronic device 3 and emitting an electrical signal according to the light intensity. The optical sensor PD can be, for example, an organic photodiode or an inorganic photodiode.

[0062] The lens element 1 is formed on the optical sensor PD. In other words, the optical sensor PD is disposed between the substrate 11 and the lens element 1. In the illustrated example, the base layer 15 of the lens element 1 covers the optical sensor PD. The lens LN is disposed directly above the optical sensor PD.

[0063] In this embodiment, by combining the optical sensor PD with the lens element 1, the light collecting ability of the light L3 incident from the upper surface is improved, and the optical sensor PD can be made smaller.

[0064] As described above, according to this embodiment, it is possible to provide a lens element and electronic equipment that can achieve desired optical performance.

[0065] All lens elements and electronic devices that can be implemented by a person skilled in the art by appropriately modifying the design based on the lens elements and electronic devices described above as embodiments of the present invention also fall within the scope of the present invention as long as they include the gist of the present invention.

[0066] Within the scope of the concept of the present invention, a person skilled in the art may conceive of various modifications, and these modifications are also understood to fall within the scope of the present invention. For example, even if a person skilled in the art appropriately adds or deletes components or modifies the design of each of the above-described embodiments, or adds or omits steps or modifies conditions, these modifications are also included within the scope of the present invention as long as they maintain the gist of the present invention.

[0067] Furthermore, with regard to other effects brought about by the aspects described in each of the above-mentioned embodiments, those that are clear from the description in this specification or that can be appropriately thought of by a person skilled in the art are naturally understood to be brought about by the present invention. [Explanation of symbols]

[0068] 1...lens element, 2...electronic device, 3...electronic device, 11...substrate, 12...circuit layer, 13...partition wall, 14...sealing layer, 15...underlayer, LN...lens, LNP...lens protective layer, OC...overcoat layer, LD...light emitting element, CF...color filter, PD...optical sensor, 16...optical film

Claims

1. A base layer and a plurality of lenses disposed on the underlayer; a lens protection layer covering each of the lenses and made of a transparent inorganic material; an overcoat layer covering the lens protection layer and having a refractive index lower than that of each of the plurality of lenses; Lens element.

2. the overcoat layer has a refractive index lower than that of the lens protection layer; The lens element of claim 1 .

3. The inorganic material is silicon nitride. The lens element of claim 1 .

4. the underlayer is a transparent organic insulating layer, the overcoat layer has a lower refractive index than the underlayer; The lens element of claim 1 .

5. the lens protection layer covers the base layer between the lenses; The lens element of claim 1 .

6. the overcoat layer covers the underlayer between the lenses; The lens element of claim 1 .

7. the thickness of the lens protection layer is smaller than the thickness of each of the lenses; The lens element of claim 1 .

8. The lens protective layer has a thickness of 50 nm or more and 300 nm or less. The lens element of claim 1 .

9. a lens element according to claim 1; a substrate; and a light-emitting element disposed between the lens element and the substrate; An electronic device comprising:

10. A color filter is further provided between the lens element and the light emitting element.

10. The electronic device according to claim 9.

11. The underlayer covers the color filter. The electronic device according to claim 10.

12. An optical film is further provided on the overcoat layer.

10. The electronic device according to claim 9.

13. A lens element according to claim 1, a substrate, and an optical sensor disposed between the lens element and the substrate; An electronic device comprising:

14. the underlayer covers the optical sensor; The electronic device according to claim 13.

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