Optical structure and optical system

Abstract

An optical construction includes a lens film and a mask layer. The lens film includes an outermost structured first major surface and an opposite outermost substantially planar second major surface. The first major surface includes a plurality of microlenses arranged along orthogonal first and second directions. The mask layer is disposed on the second major surface of the lens film and includes a first layer including a first metal, a second layer including a second metal, and a third layer disposed between the first and second layers. Each of the first and second layers has an optical reflectance greater than about 5% for substantially normally incident light, the third layer has an optical transmittance greater than about 70%, and the mask layer has an optical reflectance less than about 20%. The mask layer defines a plurality of pass-through openings that are in one-to-one alignment with the microlenses.

Description

Technical Field

[0001] This disclosure relates in general to an optical construct and an optical system, and more particularly to an optical construct and an optical system for a display. Background Technology

[0002] Devices such as mobile phones and tablets may be equipped with biometric authentication features, such as fingerprint sensors. In some cases, the fingerprint sensor is integrated under the device's display and is referred to as an under-display fingerprint sensor. An under-display fingerprint sensor transforms a defined area of ​​the display into a fingerprint sensor, thus eliminating the need for a separate physical fingerprint sensor. Summary of the Invention

[0003] In a first aspect, this disclosure provides an optical construct. The optical construct includes a lens film comprising an outermost structured first main surface and an opposite, outermost substantially flat second main surface. The structured first main surface includes a plurality of microlenses arranged along orthogonal first and second directions. The optical construct also includes a multilayer optically opaque mask layer disposed on the second main surface of the lens film opposite to the structured first main surface. The multilayer optically opaque mask layer includes: a first layer comprising a first metal; and a second layer comprising a second metal. The multilayer optically opaque mask layer further includes a third layer disposed between the first and second layers. Each of the first, second, and third layers has an average thickness of less than about 200 nanometers (nm). The first layer is disposed between the second main surface of the lens film and the third layer, such that, for substantially perpendicular incident light and for at least one wavelength in the visible wavelength range extending from about 400 nm to about 600 nm, each of the first and second layers has an optical reflectivity greater than about 5%, the third layer has an optical transmittance greater than about 70%, and the mask layer has an optical reflectivity less than about 20%. The mask layer defines a plurality of through openings extending through at least the first, second, and third layers and arranged along the first and second directions. The through openings are aligned with the microlens in a one-to-one correspondence.

[0004] In a second aspect, this disclosure provides an optical system including a display comprising a plurality of light-emitting pixels arranged along a first direction and a second direction. The optical system also includes an optical sensor positioned close to the display. Furthermore, the optical system includes an optical construct according to the first aspect, disposed between the display and the optical sensor.

[0005] In a third aspect, this disclosure provides an optical construct for absorbing visible light and transmitting infrared light. The optical construct includes a plurality of microlenses disposed on a substantially light-absorbing optical cavity system and arranged along orthogonal first and second directions. The optical cavity system includes opposing first and second reflectors defining an optical cavity between them. The optical cavity has a length of less than 200 nm, such that, for substantially perpendicular incident light and in a visible wavelength range extending from about 400 nm to about 600 nm, the optical cavity system reflects less than about 20% of the incident light and transmits less than 2% of the incident light for at least one wavelength in the visible wavelength range, and the optical construct transmits at least 10% of the incident light for at least one wavelength in the visible wavelength range. Attached Figure Description

[0006] The exemplary embodiments disclosed herein can be more fully understood in light of the following detailed description taken in conjunction with the accompanying drawings. The drawings are not necessarily drawn to scale. Similar numbers used in the drawings refer to similar parts. However, it should be understood that the use of numbers to refer to parts in a given drawing is not intended to limit parts labeled with the same numbers in another drawing.

[0007] Figure 1 This is a schematic diagram of an optical system according to one embodiment of the present disclosure;

[0008] Figure 2A This is a schematic diagram of a multilayer optically opaque mask layer according to one embodiment of the present disclosure;

[0009] Figure 2B This is a schematic diagram of the first layer of a multilayer optically opaque mask layer according to one embodiment of the present disclosure;

[0010] Figure 2C This is a schematic diagram of the second layer of a multilayer optically opaque mask layer according to one embodiment of the present disclosure;

[0011] Figure 2D This is a schematic diagram of the third layer of a multilayer optically opaque mask according to one embodiment of the present disclosure;

[0012] Figure 3A It is a graph showing an exemplary variation of the transmittance and reflectance of the light-blocking layer with the wavelength of the incident light;

[0013] Figure 3B This is an exemplary graph showing the transmittance and reflectance of another light-blocking layer as a function of the wavelength of incident light; and

[0014] Figure 4This is a graph showing an exemplary variation of the absorptivity, transmittance, and reflectivity of a multilayer optically opaque mask layer with the wavelength of incident light. Detailed Implementation

[0015] In the following description, reference is made to the accompanying drawings, which form a part thereof, and various embodiments are illustrated therein. It should be understood that other embodiments can be conceived and made without departing from the scope or spirit of this disclosure. Therefore, the following detailed description should not be considered limiting.

[0016] A display with an under-display fingerprint sensor may include a display panel, collimating optics, a light-blocking layer with holes, and an image sensor. The light-blocking layer may have low reflectivity and low transmittance in the visible light range to improve overall display contrast in dark conditions. Conventional displays with under-display fingerprint sensors use a black coating as the light-blocking layer. However, black coatings may be incompatible with display manufacturing methods. Furthermore, it may be difficult to create holes in the black coating to allow fingerprint signals to pass through. According to some aspects of this disclosure, a multilayer optically opaque mask layer is provided, which solves these and other problems associated with conventional light-blocking layers.

[0017] This disclosure relates to an optical system and an optical construct. The optical system includes a display, an optical sensor, and the optical construct. The optical system and the optical construct can be used in electronic devices including displays, such as computer monitors, televisions, mobile phones, personal digital assistants (PDAs), wearable devices, and other portable devices.

[0018] The optical construct includes a lens film and a multilayer optically opaque mask layer. The lens film includes an outermost structured first main surface and an opposite outermost substantially flat second main surface. The structured first surface includes a plurality of microlenses arranged along orthogonal first and second directions. The multilayer optically opaque mask layer is disposed on the second main surface of the lens film and includes a first layer, a second layer, and a third layer. Each of the first, second, and third layers has an average thickness of less than about 200 nanometers (nm). For substantially perpendicularly incident light having wavelengths in the visible wavelength range, each of the first and second layers has an optical reflectance greater than about 5%, and the third layer has an optical transmittance greater than about 70%. The multilayer optically opaque mask layer has an optical reflectance of less than about 20%. The multilayer optically opaque mask layer defines a plurality of through openings extending through at least the first, second, and third layers and arranged along the first and second directions. The opening is aligned with the microlens in a one-to-one correspondence.

[0019] The mask layer can be directly coated onto the flat second master surface of the lens film using vacuum deposition methods (such as electron beam evaporation, thermal evaporation, physical vapor deposition, chemical vapor deposition, or sputtering), thereby simplifying the display manufacturing process. By selecting an appropriate combination of materials for different layers and controlling the layer thickness of each layer, multilayer optically opaque mask layers can achieve low reflectivity and low transmittance in the visible light range, thus improving the overall display contrast in dark conditions. Furthermore, because the mask layer is thin, the method of drilling through openings in the mask layer is further simplified and can be performed via laser ablation.

[0020] Now refer to the attached diagram, Figure 1 An optical system 300 is shown, which includes a display 110 and an optical sensor 50 positioned close to the display 110. The optical system 300 also includes an optical construct 200 for absorbing visible light and transmitting infrared light. The optical construct 200 is disposed between the display 110 and the optical sensor 50.

[0021] The optical system 300 defines mutually orthogonal x-axis, y-axis, and z-axis. The x-axis and y-axis are in-plane axes of the optical system 300, while the z-axis is a transverse axis along the thickness of the optical system 300. In other words, the x-axis and y-axis are along the plane of the optical system 300, while the z-axis is perpendicular to the plane of the optical system 300. The display 110, optical structure 200, and optical sensor 50 of the optical system 300 are arranged adjacent to each other along the z-axis.

[0022] In some embodiments, the optical system 300 further includes a first adhesive layer 60. The first adhesive layer 60 bonds the optical construct 200 to the display 110. The first adhesive layer 60 has a refractive index of less than about 1.3 for at least one wavelength in the visible wavelength range extending from about 400 nm to about 600 nm. In some embodiments, the optical system 300 may also include a second adhesive layer 70. The second adhesive layer 70 bonds the optical construct 200 to the optical sensor 50.

[0023] The display 110 includes a plurality of light-emitting pixels 111 arranged along a first direction and a second direction. The first direction and the second direction are orthogonal to each other. The first direction may be defined along the x-axis, and the second direction may be defined along the y-axis. The light-emitting pixels 111 may emit light in response to an electric current. The light-emitting pixels 111 may include any suitable subpixel arrangement, such as a pentile matrix or an RGB matrix, depending on the application attributes.

[0024] The optical construct 200 includes a lens film 10 and a multilayer optically opaque mask layer 20 or a substantially light-absorbing optical cavity system 90. In some embodiments, the optical construct 200 includes the multilayer optically opaque mask layer 20. In other embodiments, the optical construct 200 includes the optical cavity system 90.

[0025] The lens film 10 includes an outermost structured first main surface 11 and an opposite outermost substantially flat second main surface 12. The structured first main surface 11 includes a plurality of microlenses 13 arranged along orthogonal first and second directions. The plurality of microlenses 13 may be placed on an optical cavity system 90 and arranged along the first and second directions. Specifically, the lens film 10 including the microlenses 13 is placed on the optical cavity system 90. The microlenses 13 may have at least one lateral dimension (e.g., diameter) of less than 1 millimeter (mm) and any suitable geometry. In some embodiments, the microlenses 13 may include at least one of a refractive lens, a diffractive lens, a superlens (e.g., a surface using nanostructures to focus light), a Fresnel lens, a spherical lens, an aspherical lens, a symmetrical lens (e.g., rotationally symmetrical about the optical axis), an asymmetrical lens (e.g., not rotationally symmetrical about the optical axis), or a combination thereof.

[0026] The mask layer 20 is disposed on the second main surface 12 of the lens film 10 opposite to the structured first main surface 11. The mask layer 20 includes a first layer 21, a second layer 22, and a third layer 23 disposed between the first layer 21 and the second layer 22.

[0027] The mask layer 20 defines a plurality of through openings 40 extending through at least the first layer 21, the second layer 22, and the third layer 23, and arranged along a first direction and a second direction. The through openings 40 are aligned with the microlens 13 in a one-to-one correspondence.

[0028] The optical cavity system 90 includes opposing first reflectors 21 and second reflectors 22, defining an optical cavity 91 between them. The first layer 21 can be interchangeably referred to as the first reflector 21. The second layer 22 can be interchangeably referred to as the second reflector 22. The optical cavity 91 has a length of less than 200 nm.

[0029] Each of the first reflector 21 and the second reflector 22 defines a plurality of through openings 40 therein. The through openings 40 are arranged along a first direction and a second direction and are aligned with the microlens 13 in a one-to-one correspondence.

[0030] The through opening 40 can have any suitable diameter. In some embodiments, each through opening 40 can have a diameter from about 1 micrometer (μm) to about 5 μm. In other embodiments, each through opening 40 can have a diameter of about 3 μm. The through opening 40 can be provided by any suitable method, for example, by laser ablation.

[0031] In some embodiments, the optical sensor 50 includes a plurality of sensor pixels 51 that are aligned one-to-one with the microlens 13 and through the opening 40.

[0032] The first layer 21 comprises a first metal, and the second layer 22 comprises a second metal. In some embodiments, at least one of the first layer 21 and the second layer 22 comprises one or more of titanium, chromium, nickel, copper, platinum, cobalt, tungsten, and manganese. In some embodiments, the second layer 22 comprises one or more of aluminum, gold, and silver. In some embodiments, the first layer 21 comprises titanium, and the second layer 22 comprises aluminum. In some embodiments, the third layer 23 comprises an optically transparent dielectric material. In some embodiments, the third layer 23 comprises silicon dioxide (SiO2). The choice of materials for the first layer 21, the second layer 22, and the third layer 23 may depend on the desired optical transmission and reflection properties of the materials. In some embodiments, the optical construct 200 may trap light by repeated reflections from the first layer 21 and the second layer 22. The third layer 23 may transmit light to achieve such reflections from the first layer 21 and the second layer 22.

[0033] In some implementations, the choice of materials for the first layer 21, the second layer 22, and the third layer 23 may depend on various factors, such as the adhesion of the polyethylene terephthalate (PET) film, the feasibility of laser ablation, and the cost of materials.

[0034] The first layer 21, the second layer 22, and the third layer 23 can be directly coated onto the second main surface 12 of the lens film 10 using vacuum deposition methods (such as electron beam evaporation, thermal evaporation, physical vapor deposition, chemical vapor deposition, or sputtering), thereby simplifying the manufacturing process. Furthermore, by selecting an appropriate combination of materials for the first layer 21, the second layer 22, and the third layer 23, the mask layer 20 can achieve low reflectivity and low transmittance in the visible light range, thereby improving the overall display contrast in dark conditions. In addition, the first layer 21, the second layer 22, and the third layer 23 also simplify the method of drilling through the opening 40 in the mask layer 20.

[0035] In some embodiments, the first layer 21 has an average thickness t of about 5 nm to about 50 nm, or about 5 nm to about 40 nm, or about 5 nm to about 30 nm, or about 5 nm to about 20 nm. In some embodiments, the second layer 22 has an average thickness t of about 5 nm to about 70 nm, or about 5 nm to about 60 nm, or about 5 nm to about 50 nm, or about 5 nm to about 40 nm. In some embodiments, the third layer 23 has an average thickness t of about 20 nm to about 200 nm, or about 30 nm to about 150 nm, or about 40 nm to about 120 nm, or about 50 nm to about 100 nm.

[0036] By optimizing the average thickness t of each of the first layer 21, the second layer 22, and the third layer 23 for different wavelengths, both low reflectivity and low transmittance can be achieved.

[0037] Now for reference Figure 1 and Figure 2A A first layer 21 is disposed between the second main surface 12 of the lens film 10 and the third layer 23, such that each of the first layer 21 and the second layer 22 has an optical reflectivity greater than about 5% for substantially perpendicular incident light 30 and for at least one wavelength in the visible wavelength range extending from about 400 nm to about 600 nm. In some embodiments, at least one of the first layer 21 and the second layer 22 has an optical reflectivity greater than about 10%, 15%, or 20% for the at least one wavelength in the visible wavelength range. In some embodiments, each of the first layer 21 and the second layer 22 has an optical reflectivity greater than about 10% or 15% for the at least one wavelength in the visible wavelength range. The third layer 23 has an optical transmittance greater than about 70% for the at least one wavelength in the visible wavelength range, and the mask layer 20 has an optical reflectivity less than about 20%. In some embodiments, the mask layer 20 has an optical reflectivity less than about 15% or 10% for the at least one wavelength in the visible wavelength range. In some embodiments, mask layer 20 may include more than three layers. More than three layers may further reduce the optical reflectivity of mask layer 20.

[0038] In some embodiments, the first reflector 21 and the second reflector 22 define an optical cavity 91 such that, for substantially perpendicular incident light 30 and a visible wavelength range extending from about 400 nm to about 600 nm, the optical cavity system 90 reflects less than about 20% of the incident light and transmits less than 2% of the incident light for at least one wavelength within that visible wavelength range. Additionally, for at least one wavelength within that visible wavelength range, the optical structure 200 transmits at least 10% of the incident light 30.

[0039] In some embodiments, the optical cavity 91 includes an air gap that has a relatively high optical transmittance compared to the first reflector 21 and the second reflector 22. Repeated reflections of light from the first reflector 21 and the second reflector 22 across the optical cavity 91 can trap the light within the optical cavity system 90. Therefore, the optical cavity system 90 can have a high optical absorption rate.

[0040] It can be noted that low optical transmittance and low optical reflectance of the mask layer 20 can be achieved by selecting an appropriate combination of materials for the first layer 21, the second layer 22, and the third layer 23, and by optimizing the average thickness t of each of the first layer 21, the second layer 22, and the third layer 23. For example, a larger average thickness t can be selected to reduce crosstalk (light from one microlens incident on the through-opening 40 aligned with different microlenses), or a smaller average thickness t can be selected to increase light transmitted through the through-opening 40. Similarly, the light absorption of the optical cavity system 90 can be increased by optimizing the materials and dimensions of the first reflector 21, the second reflector 22, and the optical cavity 91.

[0041] Optical sensor 50 can be configured to detect fingerprints, and a display device including display 110 (e.g., a mobile phone) can be configured to determine whether the detected fingerprint matches the fingerprint of an authorized user. In some embodiments, optical system 300 also includes an infrared light source 80 configured to emit light 81 toward the front side 42 of display 110. Infrared light source 80 assists optical sensor 50 in detecting fingerprints on display 110. Infrared light source 80 can be positioned such that it emits light 81 in a suitable direction. The light 81 emitted by infrared light source 80 can have a wavelength range extending from about 700 nm to about 1 mm.

[0042] When a finger is placed on the display 110 of the optical system 300, the finger reflects light emitted by the display 110 and / or the infrared light source 80. The reflected light passes through the display 110 and then reaches the optical construct 200 and the optical sensor 50. A mask layer 20 of the optical construct 200, having an opening 40, allows a portion of the reflected light to reach the optical sensor 50 for signal detection. Other portions of the reflected light from the finger, as well as the light emitted by the display 110 and / or the infrared light source 80, are absorbed by the mask layer 20.

[0043] Now for reference Figure 2A The image shows a mask layer 20 or an optical cavity system 90. It also shows substantially perpendicular incident light 30. The mask layer 20 includes a first layer 21, a second layer 22, and a third layer 23. The incident light 30 can be reflected and transmitted according to one or more materials selected for each of the first layer 21, the second layer 22, and the third layer 23. A combination of the first layer 21, the second layer 22, and the third layer 23 can substantially absorb the incident light 30.

[0044] The optical cavity system 90 includes a first reflector 21 and a second reflector 22. Incident light 30 can be at least partially reflected by the first reflector 21 and the second reflector 22. The optical cavity system 90 also includes an optical cavity 91 disposed between the first reflector 21 and the second reflector 22. The optical cavity 91 allows the incident light 30 to loop in a closed path due to repeated reflections from the first reflector 21 and the second reflector 22. The optical cavity system 90 and the mask layer 20 can capture the incident light 30 and a portion of the reflected light from the second layer 22.

[0045] Figure 2B A first layer 21 of the mask layer 20 is shown. In some embodiments, the first layer 21 comprises one or more of titanium, chromium, nickel, copper, platinum, cobalt, tungsten, and manganese. In some embodiments, the first layer 21 may comprise one or more of aluminum, gold, and silver. In some embodiments, the first layer 21 has an average thickness of about 5 nm to about 50 nm, or about 5 nm to about 40 nm, or about 5 nm to about 30 nm, or about 5 nm to about 20 nm.

[0046] Figure 2C A third layer 23 of the mask layer 20 is shown. In some embodiments, the third layer 23 comprises an optically transparent dielectric material. In some embodiments, the third layer 23 comprises SiO2. In some embodiments, the third layer 23 has an average thickness of about 20 nm to about 200 nm, or about 30 nm to about 150 nm, or about 40 nm to about 120 nm, or about 50 nm to about 100 nm.

[0047] Figure 2D A second layer 22 of the mask layer 20 is shown. In some embodiments, the second layer 22 comprises one or more of titanium, chromium, nickel, copper, platinum, cobalt, tungsten, and manganese. In some embodiments, the second layer 22 comprises one or more of aluminum, gold, and silver. In some embodiments, the second layer 22 has an average thickness of about 5 nm to about 70 nm, or about 5 nm to about 60 nm, or about 5 nm to about 50 nm, or about 5 nm to about 40 nm.

[0048] Now for reference Figure 3AFigure 300A shows the variation of optical transmittance and optical reflectance with the wavelength of incident light for a PET collimating optics (e.g., a lens film) coated with an aluminum layer approximately 35 nm thick. Aluminum was chosen as the light-absorbing layer because, compared to other metals, it is easier to drill micron-sized through-holes by laser ablation. The percentages of transmittance and reflectance are plotted against wavelength on the x-axis and on the y-axis. The percentage of transmittance is shown on the left y-axis. The percentage of reflectance is shown on the right y-axis. The percentage of reflectance is depicted by curve 310A, and the percentage of transmittance is depicted by curve 320A. As depicted by Figure 300A, the percentage of transmittance of incident light is less than approximately 0.5% for wavelengths from approximately 400 nm to approximately 600 nm. However, the percentage of reflectance of incident light is approximately 87% for wavelengths from approximately 400 nm to approximately 600 nm. Therefore, further reduction in reflectance may be necessary to improve the collimating optics.

[0049] Now for reference Figure 3B Figure 300B shows the variation of optical transmittance and optical reflectance with the wavelength of incident light for a PET reference straight optical device (e.g., a lens film) coated with a germanium layer of approximately 17 nm thickness and an aluminum layer of approximately 35 nm thickness. The percentages of transmittance and reflectance are plotted against wavelength on the x-axis on the y-axis. The percentage of transmittance is shown on the left y-axis. The percentage of reflectance is shown on the right y-axis. The percentage of reflectance is depicted by curve 310B, and the percentage of transmittance is depicted by curve 320B. As depicted by Figure 300B, the percentage of transmittance of incident light is less than approximately 0.24% for wavelengths from approximately 400 nm to approximately 600 nm. Additionally, the percentage of reflectance of incident light is less than approximately 20% for wavelengths from approximately 400 nm to approximately 600 nm. Therefore, compared to a collimating optics device coated with a single aluminum layer of approximately 35 nm thickness, a collimating optics device coated with a germanium layer of approximately 17 nm thickness and an aluminum layer of approximately 35 nm thickness exhibits lower transmittance and lower reflectance. However, further reductions in the transmittance and reflectance of the collimating optics may be necessary.

[0050] refer to Figure 1 and Figure 4Graph 400 illustrates the variation of optical absorptivity, optical transmittance, and optical reflectivity of incident light from an optical construct 200 according to an embodiment of the present disclosure as a function of wavelength. A first layer 21 comprises titanium. The average thickness t of the first layer 21 is approximately 13 nm. A second layer 22 comprises aluminum. The average thickness t of the second layer 22 is approximately 29 nm. A third layer 23 comprises SiO2. The average thickness t of the third layer 23 is approximately 84 nm. The percentages of absorptivity, transmittance, and reflectance are plotted relative to wavelength on the x-axis on the y-axis. The percentage of absorptivity is shown on the left y-axis. The percentages of transmittance and reflectance are shown on the right y-axis. The percentage of absorptivity is depicted by curve 410. The percentage of transmittance is depicted by curve 420. The percentage of reflectance is depicted by curve 430. It is evident from graph 400 that the optical construct 200 exhibits a low percentage of reflectance, a low percentage of transmittance, and a high percentage of absorptivity. The percentage of absorptivity may be equal to 100 - (percentage of reflectance + percentage of transmittance).

[0051] As depicted in graph 400, the percentage of incident light absorption ranges from approximately 94.5% to approximately 99.5% for wavelengths from approximately 400 nm to approximately 600 nm. The percentage of incident light transmittance is less than approximately 0.5% for wavelengths from approximately 400 nm to approximately 600 nm. The percentage of incident light reflectance is less than approximately 5.5% for wavelengths from approximately 400 nm to approximately 600 nm. (Refer to the above...) Figure 3A and Figure 3B Compared to other optical configurations discussed, optical construct 200 offers better optical properties. Specifically, optical construct 200 offers lower transmittance and lower reflectance. Therefore, the three-layer configuration of optical construct 200 provides improved light-blocking performance compared to a single aluminum layer or a two-layer configuration including aluminum and germanium.

[0052] Unless otherwise stated, all figures used in the specification and claims to indicate feature dimensions, quantities, and physical properties should be understood to be modified by the term "about". Therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations and can vary according to the desired properties sought by those skilled in the art using the teachings disclosed herein.

[0053] While specific embodiments have been illustrated and described herein, those skilled in the art will recognize that various alternative and / or equivalent embodiments may be used in place of the illustrated and described embodiments without departing from the scope of this disclosure. This application is intended to cover any modifications or variations of the specific embodiments discussed herein. Therefore, this disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. An optical structure for absorbing visible light and transmitting infrared light, the optical structure comprising: The lens film includes an outermost structured first main surface and an opposite outermost substantially flat second main surface, the structured first main surface including a plurality of microlenses arranged along an orthogonal first and second direction; and A multilayer optically opaque mask layer, wherein the multilayer optically opaque mask layer is directly coated onto the second main surface of the lens film opposite to the structured first main surface by vacuum deposition, and comprises: The first layer includes a first metal; The second layer, the second layer comprising a second metal; and A third layer, disposed between the first and second layers and directly adjacent to both the first and second layers, each of the first, second, and third layers having an average thickness of less than 200 nm, the first layer being disposed between the second main surface of the lens film and the third layer, such that for substantially perpendicular incident light, and for at least one wavelength in the visible wavelength range extending from 400 nm to 600 nm: Each of the first layer and the second layer has an optical reflectivity greater than 5%; The third layer has an optical transmittance of greater than 70%; and The mask layer has an optical reflectivity of less than 20%; The optical structure traps light through repeated reflections from the first and second layers, and the third layer transmits light to achieve such reflections from the first and second layers. Multiple through-holes are drilled in the mask layer by laser ablation. The multiple through-holes extend through at least the first layer, the second layer and the third layer. Each of the multiple through-holes has the same diameter in the first layer, the second layer and the third layer and is arranged along the first direction and the second direction. The through-holes are aligned with the microlens in a one-to-one correspondence.

2. The optical construct of claim 1, wherein each of the first layer and the second layer has an optical reflectivity greater than 15% for at least one wavelength in the visible wavelength range.

3. The optical construct of claim 1, wherein the mask layer has an optical reflectivity of less than 10% for the at least one wavelength in the visible wavelength range.

4. The optical structure according to claim 1, wherein the first layer has an average thickness of 5 nm to 50 nm, wherein the second layer has an average thickness of 5 nm to 70 nm, and wherein the third layer has an average thickness of 20 nm to 200 nm.

5. The optical construct of claim 1, wherein the first layer comprises titanium and the second layer comprises aluminum.

6. The optical construct of claim 1, wherein the third layer comprises silicon dioxide.

7. An optical system, the optical system comprising: A display comprising a plurality of light-emitting pixels arranged along a first direction and a second direction; An optical sensor is positioned close to the display; as well as The optical structure according to claim 1 is disposed between the display and the optical sensor.

8. The optical system of claim 7, wherein the optical sensor comprises a plurality of sensor pixels aligned in a one-to-one correspondence with the microlens and the through-aperture, and wherein the optical system further comprises an infrared light source configured to emit light toward the front side of the display.

9. An optical construct for absorbing visible light and transmitting infrared light, said optical construct comprising: A plurality of microlenses are disposed on a substantially light-absorbing optical cavity system and arranged along orthogonal first and second directions. The optical cavity system includes opposing first and second reflectors defining an optical cavity between them. The optical cavity includes an air gap having a relatively high optical transmittance compared to the first and second reflectors. The optical cavity, the first reflector, and the second reflector are configured such that light is repeatedly reflected from the first and second reflectors across the optical cavity, thereby trapping light within the optical cavity system. The optical cavity has a length of less than 200 nm, which is sufficient for substantially perpendicular incident light and the visible wavelength range extending from 400 nm to 600 nm. For at least one wavelength within the visible wavelength range, the optical cavity system reflects less than 20% of the incident light and transmits less than 2% of the incident light; and For at least one wavelength within the visible wavelength range, the optical structure transmits at least 10% of the incident light. Multiple through openings are drilled in each of the first and second reflectors by laser ablation. These through openings are arranged along the first and second directions and aligned with the microlenses in a one-to-one correspondence.

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