Optical system and method including microlens and light blocking layer

Abstract

The present invention discloses an optical system, and the optical system includes: an optical sensor, which is configured to receive light and form an image. The optical system also includes: a microlens film, which includes a structured first main surface, which is opposite to the second main surface, and the structured first main surface includes a regularly spaced microlens array arranged across the width and length of the microlens film, and each microlens has an effective imaging area and is configured to form an image onto the optical sensor. A light absorbing layer, which is arranged on the spaced microlens array and reduces the effective imaging area of ​​each microlens by at least 10%. A display panel, the optical sensor, the microlens film and the display plane substantially extend together along the width and length of the microlens film.

Description

Background Art

[0001] The optical system may include a plurality of microlenses for focusing and transmitting light. Various arrangements of optical elements may facilitate selective transmission of light through the microlenses based on certain angular ranges. Summary of the invention

[0002] In some aspects, an optical system is disclosed. The optical system may include an optical sensor and a microlens film, the optical sensor being configured to receive light and form an image. The microlens film may include a structured first major surface, the structured first major surface being opposite to the second major surface, the structured first major surface may include a regularly spaced array of microlenses arranged across the width and length of the microlens film, each microlens may have an effective imaging area and be configured to form an image onto the optical sensor. A light absorbing layer may be disposed on the spaced array of microlenses and reduce the effective imaging area of ​​each microlens by at least 10%. The display panel, the optical sensor, the microlens film, and the display plane may substantially coexist with each other along the width and length of the microlens film, so that when an object having a first spatial frequency of about 4 line pairs / mm is placed about 1.5 mm from the microlens film, each microlens forms an image of the object on the optical sensor, and the image has a modulation transfer function (MTF) greater than about 0.2 at the first spatial frequency.

[0003] In some aspects, an optical film is disclosed. The optical film may include a microlens film, the microlens film including a structured first major surface, the structured first major surface opposite to the second major surface, the structured first major surface may include a regularly spaced array of microlenses arranged at a pitch P across the width and length of the microlens film. Each microlens may be configured to have a half field of view θ. A light absorbing layer may be disposed on the structured first major surface and cover the area between the microlenses and at least a portion of the microlenses so as to reduce the effective imaging area of ​​the microlenses by at least 10%. The microlens film may have an average thickness D and an effective refractive index n along the thickness direction of the microlens film, such that P, θ, and n are related by the following formula:

[0004] In some aspects, an optical construct is disclosed. The optical construct may include a structured optical film including a structured first major surface having a first surface energy and a regularly spaced array of structures arranged across the width and length of the structured optical film, and each structure may have a maximum height H1. An intermediate optical layer may be disposed on the structured first major surface and substantially coextensive therewith, and include a structured second major surface opposite the structured first major surface. The structured second major surface may have a second surface energy that is at least 20% less than the first surface energy, and the intermediate optical layer may have a maximum thickness H2, where H2≤0.1H1. A light absorbing layer may be disposed on the structured second major surface and substantially coextensive therewith, and cover the region between the structures and at least a portion of the intermediate optical layer corresponding to the structure, so that the optical transmittance of the optical construct in the region between the structures is at least 10 times less than the optical transmittance of the optical construct in the region corresponding to the structure.

[0005] The systems, structures, and features disclosed herein can improve the signal-to-noise ratio when detecting an image, such as a fingerprint, from behind a display via an optical sensor. Other benefits and uses are also contemplated. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a schematic side elevation view of an optical system according to an exemplary embodiment of the present disclosure.

[0007] Figure 2 is a schematic perspective view of an exemplary microlens film according to an exemplary embodiment of the present disclosure.

[0008] Figure 3 is a schematic perspective view of an exemplary microlens film and a light absorbing layer according to an exemplary embodiment of the present disclosure.

[0009] Figure 4 is a schematic side elevation view of an optical layer according to an exemplary embodiment of the present disclosure.

[0010] Figure 5 is a schematic top view of an optical layer according to an exemplary embodiment of the present disclosure, particularly illustrating an effective imaging area and a microlens surface area.

[0011] Figure 6 is a schematic side view of an optical layer according to an exemplary embodiment of the present disclosure.

[0012] Figure 7 is a schematic side view of an optical layer according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0013] In the following description, reference is made to the accompanying drawings, which form a part of the present invention and in which various embodiments are shown by way of example. The drawings are not necessarily drawn to scale. It should be understood that other embodiments may be conceived and carried out without departing from the scope or essence of the present description. Therefore, the following specific embodiments should not be considered to have a limiting meaning.

[0014] It may be desirable to use an optical device to transmit light to an optical sensor. To prevent certain angled light rays from passing through the optical layer from a reflective source, various structures, materials, and geometries may be employed that also allow certain other light rays to pass through. Such a system may, for example, improve the signal-to-noise ratio of an optical sensor disposed within an electronic device.

[0015] Figure 1 is an exemplary side elevation view of an exemplary optical system 100. The optical system 100 may include a display 104 (or display panel) and an optical sensor 112. In some embodiments, the display 104 may include an emissive display, such as an organic light emitting diode (OLED) or micro-LED (light emitting diode), or a transmissive display, such as a liquid crystal display (LCD).

[0016] The optical sensor 112 may be divided into a plurality of light-gathering photosensitive picture elements or pixels 114. The optical sensor 112 may include a charge coupled device, a complementary metal oxide semiconductor, or may employ any other light-sensitive sensor technology or combination of light-sensitive technologies. Additionally, the optical sensor 112 may include one or more photosensors, organic photosensors, photodiodes, and / or organic photodiodes.

[0017] In some embodiments, the optical system 100 includes an optical layer 130. The optical layer 130 can be substantially disposed between the optical sensor 112 and the display 104. The optical layer 130 can include a microlens film 140 that defines a structured first major surface 144 and a second major surface 148. The structured first major surface 144 and the second major surface 148 can be disposed on substantially opposite sides of the microlens film 140. A plurality of microlenses 142 can be formed on the microlens film 140, and in some embodiments, can be formed on the structured first major surface 144.

[0018] The optical sensor 112, the microlens film 140 and / or the optical layer 130 may be flexible. Such flexible optical sensor 112, the microlens film 140 and / or the optical layer 130 may have the property of being bendable without cracking. Such flexible optical sensor 112, the microlens film 140 and / or the optical layer 130 may also be capable of being formed into a roll. In some embodiments, the flexible optical sensor 112, the microlens film 140 and / or the optical layer 130 may be bent around a roll core having a radius of curvature of: 7.6 centimeters (cm) (3 inches), 6.4 cm (2.5 inches), 5 cm (2 inches), 3.8 cm (1.5 inches), 2.5 cm (1 inch), 1.9 cm (3 / 4 inches), 1.3 cm (1 / 2 inches) or 0.635 cm (1 / 4 inches).

[0019] The microlens film 140 and the microlens 142 may be formed of a common material. The material may be a polymer material having certain thermal or rheological properties. For example, the material may have a sufficiently high glass transition temperature to maintain its form or rigidity during processing. In some embodiments, the material may be microreplicated by a continuous casting and curing microreplication process. Such materials may be cured by applying radiation (such as heat or ultraviolet light). In some embodiments, the microlens film 140 and the microlens 142 may include polyethylene terephthalate. In some embodiments, the microlens 142 may be formed on a substrate that may include polycarbonate by continuous casting and curing. In some embodiments, the microlens film 140 may be formed on polyethylene terephthalate and / or polycarbonate using a photocurable material.

[0020] Figure 2 Illustrated is an exemplary microlens film 140. Also shown are the microlens film width W and the microlens film length L along with the microlenses 142 and the structured first major surface.

[0021] Figure 3 An exemplary microlens film 140 is illustrated, and a light absorbing layer 170 is also shown. The light absorbing layer 170 can be substantially coextensive with the microlens film 140. In some embodiments, the light absorbing layer 170 is adjacent to, engaged with, in contact with, and / or in proximity to the microlens film 140. In some embodiments, the thickness of the light absorbing layer 170 on one of the microlenses 142 as measured along an axis perpendicular to the second major surface 148 is greater than the thickness of the light absorbing layer 170 on the area of ​​the microlens film 140 located between the microlenses 142 as measured along the axis perpendicular to the second major surface 148. In some embodiments, the light absorbing layer 170 is adjacent to, engaged with, in contact with, and / or in proximity to the structured first major surface 144.

[0022] Figure 4Exemplary embodiments of optical layer 130 are illustrated. In some embodiments, light absorbing layer 170 may include or be formed from a mixture of a binder, a light blocking material, and a solvent. Upon sufficient evaporation of the solvent, light absorbing layer 170 may be formed continuously or discontinuously on microlenses 142 and structured first major surface 144. The light blocking material may include a dye or a pigment. In some embodiments, the light blocking material includes Orasol TM X45 black dye (BASF).

[0023] The binder may include one or more of the following: solvent-soluble nitrocellulose, ester-soluble nitrocellulose, cellulose acetate butyrate, cellulose acetate propionate, ethyl cellulose, maleic acid resins, ketone resins, shellac, alcohol-soluble polyamide resins, urea and melamine / formaldehyde resins, polyvinyl chloride copolymers, polyvinyl acetal resins, polyacrylic resins, epoxy resins, polyurethane resins, polyester resins, alkyd resins, and polyvinyl butyral (such as PVB 30H, or any PVB in the Mowital group from Kuraray).

[0024] The solvent may include one or more of the following: methyl ethyl ketone (MEK), acetone, methanol, ethanol, isopropanol, ethyl acetate, methyl isobutyl ketone, and 1-methoxy-2-propanol. In some embodiments, the light absorbing layer 170 includes 6.8 wt % Orasol TM X45 black dye (BASF), 8.2 wt% Mowital TM Polyvinyl butyral (PVB 30H) and 85 wt% methyl ethyl ketone (MEK). In some embodiments, the polymer binder can be polymerized after the desiccant is applied, such as in the case where the dye is mixed with a UV-curable acrylate monomer and a photoinitiator.

[0025] like Figure 4140 , at least one microlens 142 defines a microlens diameter D and a microlens height H. Although D may be used to indicate the diameter across a circular or substantially circular microlens 142, it should be understood that D may be used to indicate the distance across a microlens 142 having any shape, the distance across a microlens 142 as measured along the shortest distance between portions of the microlens film 140 on opposite sides of the microlens 142, and / or an average of all possible distances across the microlens 142. The microlens height H may be used to indicate the height from a base B of the microlens 142 to an apex A of the microlens 142. The base B may be defined as a point in space equidistant from opposing microlens 142 edges that are adjacent to portions of the microlens film 140 on opposite sides of the microlens 142. The microlenses 142 may each have substantially the same shape (e.g., spherical or non-spherical), diameter D, height H, size, and / or aspect ratio (ratio of height H to diameter D).

[0026] In some embodiments, the microlens height H of one or more microlenses 142 is greater than the diameter D of the one or more microlenses 142. In some embodiments, the microlens diameter D of the one or more microlenses 142 is approximately 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the microlens height H of the one or more microlenses 142. In some embodiments, the microlens height H of one or more microlenses 142 is less than the microlens diameter D of the one or more microlenses 142. In some embodiments, the microlens height H of one or more microlenses 142 is approximately 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the diameter D of the one or more microlenses 142. In some embodiments, the microlens height H of one or more microlenses 142 is approximately equal to the diameter D of the one or more microlenses 142.

[0027] In various embodiments, the microlens height H can be approximately 1 micron, 2 microns, 3 microns, 4 microns, 5 microns, 6 microns, 7 microns, 8 microns, 9 microns, 10 microns, 15 microns, 20 microns, 25 microns, 30 microns, 35 microns, 40 microns, 45 microns, 50 microns, 55 microns, 60 microns, 65 microns, 70 microns, 75 microns, 80 microns, 85 microns, 90 microns, 95 microns, 100 microns, 150 microns, 200 microns, or 250 microns, and the microlens diameter D can be approximately 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 210, 225, 250, 275, 300, 350, 400, 450, or 500 microns. Furthermore, in some implementations, the microlenses 142 can be spaced apart on the microlens film 140 at a pitch of approximately 700 microns.

[0028] In some embodiments, the effective imaging area 153 can be defined as a portion of the microlens 142 through which a certain percentage of incident light passes, such as Figure 5 In some embodiments, the effective imaging area 153 can be substantially the surface area 155 of the microlens 142. In some embodiments, the effective imaging area 153 can be smaller than the surface area 155 of the microlens 142. In some embodiments, the effective imaging area 153 can be reduced by a light absorbing layer 170, which can prevent light from passing through the microlens 142 and / or some portions of the microlens surface area 155.

[0029] In some embodiments, the effective imaging area 153 defines a portion of the microlens 142 through which at least about 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of the incident light passes. In some embodiments, the size of the effective imaging area 153 is reduced by the light absorbing layer 170 by about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%. In some embodiments, the size of the effective imaging area 153 is reduced by the light absorbing layer 170 by at least about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%.

[0030] In some embodiments, the display 104, the optical sensor 112, and / or the microlens film 140 substantially extend together along the length L and width W of the microlens film 140, which may indicate that the display 104, the optical sensor 112, and / or the microlens film 140 are adjacent, in contact, close to, and / or formed on each other.

[0031] As is known in the art, the modulation transfer function (MTF) can be a useful quantity to characterize resolution. The MTF can be determined by displaying an image of a line chart at a given spatial frequency and determining the maximum intensity and the minimum intensity in the displayed image. The MTF is given by the ratio of the difference between the maximum intensity and the minimum intensity divided by the sum of the maximum intensity and the minimum intensity. In the present disclosure, in various embodiments, when an object 174 having a spatial frequency of about 4 line pairs / mm is placed about 1.5 mm from the microlens film 140, the light absorbing layer 170, or the optical layer 130, the image 193 formed by each microlens 142 on the optical sensor 112 has an MTF greater than about 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, or 0.5 at the spatial frequency.

[0032] In some embodiments, all of the microlenses 142 except the first microlens are covered so that only the first microlens 142 forms an image of the object 174 on the optical sensor 112. In this case, the MTF of the image 197 formed on the optical sensor 112 by the first microlens 142 is increased by less than about 5%, 10%, 15%, 20%, or 25%. In some embodiments, the microlens film 140 and the microlenses 142 can include polyethylene terephthalate (and can also be formed of a UV-curable polymer composition on a PET film).

[0033] Angular frequency can be used to measure the resolution of the imaging system independently of the imaging distance and the object distance. Angular frequency can be defined as (number of cycles) / (angular range of the number of cycles when the object is imaged by the microlens). In some embodiments, when the object 174 has a first angular frequency of about 6 cycles / radian and is placed in front of the microlens film 140, each microlens 142 forms an image 198 of the object on the optical sensor 112, which has a modulation transfer function (MTF) greater than about 0.2 at the first angular frequency. In various embodiments, the image 198 of the object on the optical sensor 112 may have a modulation transfer function (MTF) greater than about 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, or 0.5 at the first angular frequency.

[0034] In some embodiments, such as Figure 6As can be seen in FIG, the microlens film 140 may define a structured first major surface 144 and a second major surface 148. The structured first major surface 144 and the second major surface 148 may be disposed on substantially opposite sides of the microlens film 140. The structured first major surface 144 may include an array of regularly spaced microlenses 142 arranged at a pitch P across a width W and a length L of the microlens film 140. In some embodiments, the array of regularly spaced microlenses 142 includes a hexagonal or hexagonally packed array in which each microlens 142 is substantially equidistant from the six closest other microlenses 142, or a square grid-shaped array in which each microlens 142 is substantially equidistant from the four closest other microlenses 142 (e.g., Figure 2 and Figure 3 Other arrangements are within the scope of the present disclosure, such as triangular arrays, rectangular arrays, pentagonal arrays, heptagonal arrays, and octagonal arrays.

[0035] In some embodiments, each microlens 142 is configured to have a half field of view θ. The light absorbing layer 170 can be disposed on at least a portion of the structured first major surface 144, and can be further disposed to at least partially cover the region of the structured first major surface 144 between the microlenses 142. In addition, the light absorbing layer 170 can cover at least a portion of the microlenses 142 to reduce the effective imaging area 153 of the microlenses 142 by at least 10%, as described above.

[0036] like Figure 6 As shown, the microlens film 140 can have an average thickness D and an effective refractive index n along the thickness direction of the microlens film (indicated by the arrow showing the length D). The microlens film 140 can include a microlens layer 205, a substrate 209, and a refractive index matching layer 207 disposed between the microlens layer 205 and the substrate 209. In some embodiments, the substrate 209 includes polycarbonate.

[0037] In some embodiments, P, n, D, and θ are related by the following equation:

[0038]

[0039] In various embodiments, θ can be at least 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, or 70 degrees. As described above, the light absorbing layer 170 can be disposed as a continuous layer or a substantially continuous layer disposed above, on, adjacent to, and / or proximate to the microlenses 142 and / or the structured first major surface 144.

[0040] In some embodiments, an optical construct 300 is disclosed. Figure 7The optical construction 300 best shown includes a microlens film 140. The microlens film 140 can define a structured first major surface 144 and a regularly spaced array of structures or microlenses 142, as described above. The structured first major surface 144 can have a first surface energy. Each microlens 142 can have a maximum height H1. In some embodiments, as Figure 7 As an example, H1 may be measured from a base B of the microlens 142 to an apex A of the microlens 142 .

[0041] Optical construct 300 can also include intermediate optical layer 304. Intermediate optical layer 304 can be disposed on, adjacent to, proximate to, and / or in contact with structured first major surface 144. In some embodiments, intermediate optical layer 304 is substantially coextensive with structured first major surface 144. Intermediate optical layer 304 can define structured second major surface 308. Structured second major surface 308 can be located on a side of intermediate optical layer 304 that is substantially opposite to another side of intermediate optical layer 304 that is adjacent to, proximate to, and / or in contact with structured first major surface 144.

[0042] In some embodiments, the acceptance of the light absorbing layer 170 on the structured first major surface 144 without the light absorbing layer 170 forming beads can be defined as the "wettability" of the structured first major surface 144. Wettability can refer to a mixture of a binder, a light blocking material, and a solvent (which forms the light absorbing layer 170) that maintains the continuity of the light absorbing layer on the structured first major surface 144, such that when the mixture dries, a continuous layer is formed over the first structured major surface 144 and the microlenses 142. "Dewetting" of the mixture can cause the mixture to break, such that holes appear in the mixture as applied on the structured first major surface 144. Wetting of the structured first major surface 144 can be achieved if the surface tension of the mixture when deposited on the structured first major surface 144 is lower than the surface energy of the substrate (or of the structured first major surface 144). In order to obtain the desired wettability of structured first major surface 144, the surface tension of the mixture can be substantially lower than the surface energy of structured first major surface 144, and in various embodiments, can be or can be about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of the surface energy of structured first major surface 144. When the surface tension of the mixture is higher than the surface energy of the structured first major surface, dewetting of the mixture can occur. It has been observed that when the surface tension of the mixture approaches the surface energy of microlenses 142 or structured first major surface 144, the mixture begins to dewet at the surface of microlenses 142, thereby freeing microlenses 142 from the mixture, and thus freeing light absorbing layer 170 from the mixture when the solvent dries from the mixture.

[0043] A typical range of surface energy for microlenses 142 can be in the range of 30 dynes / cm-55 dynes / cm. A typical mixture can have a surface tension in the range of 22 dynes / cm-45 dynes / cm. To promote dewetting of the mixture from the microlenses 142 and / or the structured first major surface 144, the surface energy of the structured first major surface 144 can be reduced relative to the surface tension of the mixture. The intermediate optical layer 304 can promote dewetting of at least a portion of the mixture. The intermediate optical layer 304 layer can be selected to have a surface energy sufficiently lower than the surface tension of the mixture. A suitable surface energy for the intermediate optical layer 304 can be as low as 20 dynes / cm, which would be lower than the typical mixture surface tension of 24 dynes / cm.

[0044] In some embodiments, the surface tension of the mixture can be substantially lower than the surface energy of the intermediate optical layer 304, and in various embodiments can be or can be about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of the surface energy of the intermediate optical layer 304.

[0045] In some embodiments, the surface tension of the mixture can be or can be about 1 dyne / cm, 2 dynes / cm, 3 dynes / cm, 4 dynes / cm, 5 dynes / cm, 10 dynes / cm, 15 dynes / cm, 24 dynes / cm, 25 dynes / cm, 30 dynes / cm, 35 dynes / cm, 40 dynes / cm, 45 dynes / cm, 50 dynes / cm, 60 dynes / cm, 70 dynes / cm, 80 dynes / cm, 90 dynes / cm, 100 dynes / cm, 200 dynes / cm, 500 dynes / cm, or 1000 dynes / cm. In some implementations, the surface energy of the intermediate optical layer 304 can be or can be about 1 dyne / cm, 2 dynes / cm, 3 dynes / cm, 4 dynes / cm, 5 dynes / cm, 10 dynes / cm, 15 dynes / cm, 24 dynes / cm, 25 dynes / cm, 30 dynes / cm, 35 dynes / cm, 40 dynes / cm, 45 dynes / cm, 50 dynes / cm, 60 dynes / cm, 70 dynes / cm, 80 dynes / cm, 90 dynes / cm, 100 dynes / cm, 200 dynes / cm, 500 dynes / cm, or 1000 dynes / cm. In some embodiments, the surface energy of structured first major surface 144 can be or can be approximately 1 dyne / cm, 2 dynes / cm, 3 dynes / cm, 4 dynes / cm, 5 dynes / cm, 10 dynes / cm, 15 dynes / cm, 24 dynes / cm, 25 dynes / cm, 30 dynes / cm, 35 dynes / cm, 40 dynes / cm, 45 dynes / cm, 50 dynes / cm, 60 dynes / cm, 70 dynes / cm, 80 dynes / cm, 90 dynes / cm, 100 dynes / cm, 200 dynes / cm, 500 dynes / cm, or 1000 dynes / cm.

[0046] Intermediate optical layer 304 can facilitate dewetting of at least a portion of a mixture (which forms light absorbing layer 170, as described above) comprising a solvent and a light blocking material from regions 312 of optical construct 300 corresponding to microlenses 142 to regions 316 of optical construct 300 between microlenses 142. In some embodiments, intermediate optical layer 304 enables dewetting of at least a portion of the mixture from regions 312 of optical construct 300 corresponding to microlenses 142 to regions 316 of optical construct 300 between microlenses 142, whereas that portion of the mixture would not dewet from regions 312 of optical construct 300 corresponding to microlenses 142 to regions 316 of optical construct 300 between microlenses 142 in the absence of intermediate optical layer 304.

[0047] The structured second major surface 308 may have a second surface energy, and the second surface energy may be less than the first surface energy. In various embodiments, the second surface energy is about 0.001%, 0.005%, .01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% of the first surface energy. In various embodiments, the second surface energy is less than about 0.001%, 0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% of the first surface energy.

[0048] The intermediate optical layer 304 may have a maximum thickness H2. In some embodiments, H2 ≤ H1. In some embodiments, H2

[0049] The light absorbing layer 170 can be disposed on, proximate to, in contact with, and / or adjacent to the intermediate optical layer 304. In various embodiments, the light absorbing layer 170 can be disposed on, proximate to, in contact with, and / or adjacent to the structured second major surface 308. In some embodiments, the light absorbing layer 170 is substantially coextensive with the intermediate optical layer 304 and / or the structured second major surface 308.

[0050] The light absorbing layer 170 may be at least partially disposed between the microlenses or structures 142. In some embodiments, the light absorbing layer 170 may also be disposed on, adjacent to, near, and / or in contact with a portion of the intermediate optical layer 304 corresponding to or disposed on the microlenses or structures 142. In some embodiments, the light absorbing layer 170 is discontinuously disposed on, adjacent to, in contact with, and / or near the intermediate optical layer 304. In addition, in some embodiments, the light absorbing layer 170 is not disposed on, adjacent to, in contact with, and / or near at least a portion of the region 316 of the optical structure 300 corresponding to the microlenses 142.

[0051] ​In some embodiments, the optical transmittance of a particular element can be described as the percentage of light incident on the element that passes through the element. In various embodiments, the optical transmittance of the optical fabric 300 in the regions 316 between the microlenses 142 can be at least about 2, 5, 10, 25, 50, 100, 150, 200, 250, 500, 1000, or 5000 times less than the optical transmittance of the optical fabric 300 in the regions 312 corresponding to the microlenses 142. In some embodiments, the optical transmittance of the optical fabric 300 in the regions 316 between the structures or microlenses 142 can be about 2, 5, 10, 25, 50, 100, 150, 200, 250, 500, 1000, or 5000 times less than the optical transmittance of the optical fabric 300 in the regions 312 corresponding to the structures. In some implementations, the intermediate optical layer 304 can include silicones, polyolefins, fluorinated materials, and mixtures thereof.

[0052] All references, patents, and patent applications cited above are hereby incorporated by reference in their entirety in a consistent manner. In the event of inconsistencies or conflicts between an incorporated reference portion and the present application, the information in the foregoing description shall prevail.

[0053] Unless otherwise indicated, the description of the elements in the drawings should be understood to apply equally to the corresponding elements in the other drawings. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that the specific embodiments shown and described may be replaced with a variety of alternative and / or equivalent embodiments without departing from the scope of the present disclosure. The present application is intended to cover any modification or variation of the specific embodiments discussed herein. Therefore, the present disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. An optical system, comprising: an optical sensor configured to receive light and form an image; A microlens film, the microlens film comprising: a structured first major surface, the structured first major surface opposite the second major surface, the structured first major surface comprising an array of regularly spaced microlenses arranged across the width and length of the microlens film, each microlens having an active imaging area and configured to form an image onto the optical sensor; and a light absorbing layer disposed on the spaced-apart microlens array and reducing the effective imaging area of ​​each microlens by at least 10%; and The display panel, the optical sensor, the microlens film and the display plane are substantially coextensive with each other along the width and the length of the microlens film, so that when an object having a first spatial frequency of 4 line pairs / mm is placed 1.5 mm away from the microlens film, each microlens forms an image of the object on the optical sensor, and the image has a modulation transfer function (MTF) greater than 0.2 at the first spatial frequency.

2. The optical system of claim 1 , wherein when all of the microlenses except a first microlens are covered so that only the first microlens forms an image of the object on the optical sensor, the modulation transfer function (MTF) of the image formed by the first microlens onto the optical sensor increases by less than 10%.

3. The optical system of claim 1, wherein the light absorbing layer is continuous on the structured first major surface.

4. The optical system of claim 1, wherein the microlens film comprises polyethylene terephthalate.

5. The optical system of claim 1 , wherein the array of regularly spaced microlenses is arranged at a pitch P across the width and length of the microlens film, each microlens being configured to have a half field of view θ; the microlens film having an average thickness D and an effective refractive index n along the thickness direction of the microlens film, such that P, θ, and n are related by the following formula: The optical system of claim 5 , wherein θ is at least 20 degrees. The optical system of claim 5 , wherein θ is at least 30 degrees.

8. The optical system of claim 5, wherein θ is at least 40 degrees.

9. The optical system of claim 5, wherein the light absorbing layer is continuous on the structured first major surface.

10. The optical system of claim 1 , wherein the object having a first angular frequency of 6 cycles / radian is placed in front of the microlens film, each microlens forming an image of the object on the optical sensor, the image having a modulation transfer function (MTF) greater than 0.2 at the first angular frequency.

Images