Partial refraction or partial reflection of light received by a cellulose-based film containing a surface pattern

Abstract

Detecting modifications of optically active cellulose-based films is provided. [Solution] The method includes a step of splitting, refracting or splitting and reflecting light received by a surface pattern of an optically active cellulose-based film into multiple output light patterns, one output light pattern being determined from the multiple output light patterns based on modifications applied to the optically active cellulose-based film.

Description

Technical Field

[0001] The present invention relates to the split refraction or split reflection of light received by a cellulose film including a surface pattern.

Background Art

[0002] This chapter intends to provide the background or situation of the present invention described in the claims. The description in this specification may include concepts that, although claimed, were not necessarily previously conceived or claimed. Therefore, unless specifically stated otherwise, the matters described in this chapter are not prior art with respect to the specification and claims of this application, and are not recognized as prior art by being included in this chapter.

[0003] Cellulose films are biodegradable and transparent. In many applications, cellulose films are exposed to various conditions that can potentially have an adverse effect on cellulose films or products similar to cellulose films. These various conditions may not be detected and may be overlooked, and in such cases, their adverse effects may also be overlooked. The detection of these conditions is important, at least in applications where reliable product quality is required.

Summary of the Invention

Means for Solving the Problems

[0004] The scope of protection sought in various embodiments of the present invention is indicated by the independent claims. Embodiments, examples, and features (if any) described herein that do not fall within the scope of the independent claims should be construed as useful examples for understanding the various embodiments of the present invention.

[0005] An apparatus according to a first embodiment includes an optical position sensor device and a processor, the processor being configured to control the optical position sensor device to capture data from an optically active cellulose film located within the field of view of the optical position sensor device, wherein the optically active cellulose film includes a surface pattern configured to split and refract or split and reflect received light into a plurality of output light patterns, and one output light pattern is determined from the plurality of output light patterns based on a modification applied to the optically active cellulose film, and the processor is configured to perform the steps of determining the modification applied to the optically active cellulose film based on captured data showing changes in one or more output light patterns in response to the modification applied to the optically active cellulose film.

[0006] A method according to a second embodiment includes the steps of capturing data from an optically active cellulose film located within the field of view of an optical position sensor device, wherein the optically active cellulose film includes a surface pattern configured to split and refract or split and reflect received light into a plurality of output light patterns, and one output light pattern is determined from the plurality of output light patterns based on a modification applied to the optically active cellulose film; and determining the modification applied to the optically active cellulose film based on captured data showing changes in one or more output light patterns in response to the modification applied to the optically active cellulose film.

[0007] The optically active cellulose film according to the third embodiment is: The optically active cellulose film includes a surface pattern configured to split and refract or split and reflect received light into multiple output light patterns, wherein one output light pattern is determined from the multiple output light patterns based on the modification applied to the optically active cellulose film.

[0008] A method according to a fourth embodiment includes the step of splitting and refracting or splitting and reflecting light received by a surface pattern of an optically active cellulose film into a plurality of output light patterns, wherein one output light pattern is determined from the plurality of output light patterns based on a modification applied to the optically active cellulose film.

[0009] A computer program according to a fifth embodiment includes computer-readable program code means adapted to perform at least the steps of: capturing data from an optically active cellulose film located within the field of view of an optical position sensor device, wherein the optically active cellulose film includes a surface pattern configured to split and refract or split and reflect received light into a plurality of output light patterns, and one output light pattern is determined from the plurality of output light patterns based on a modification applied to the optically active cellulose film; and determining the modification applied to the optically active cellulose film based on captured data showing changes in one or more output light patterns in response to the modification applied to the optically active cellulose film. [Brief explanation of the drawing]

[0010] For a more complete understanding of exemplary embodiments of the present invention, please refer to the following description in conjunction with the accompanying drawings.

[0011] [Figure 1a] This document shows a cellulose-based film including a surface pattern according to at least some embodiments of the present invention. [Figure 1b] This document shows a cellulose-based film including a surface pattern according to at least some embodiments of the present invention. [Figure 2a] This document shows a cellulose-based film including a surface pattern according to at least some embodiments of the present invention. [Figure 2b] This document shows a cellulose-based film including a surface pattern according to at least some embodiments of the present invention. [Figure 3]The present invention illustrates methods according to at least some embodiments. [Figure 4] The present invention illustrates methods according to at least some embodiments. [Figure 5] The present invention illustrates methods according to at least some embodiments. [Figure 6] This shows the changes in the surface pattern according to at least some embodiments of the present invention. [Figure 7] The block diagrams shown are of devices according to at least some embodiments of the present invention. [Modes for carrying out the invention]

[0012] The following embodiments are illustrative. While this specification may refer to “one,” “one,” and “several” embodiments in some places, this does not necessarily mean that each such reference is to the same embodiment or that a feature applies only to a single embodiment. A single feature from different embodiments may be combined to provide other embodiments.

[0013] The optically active cellulose film is provided with the ability to split and refract or split and reflect light received by a surface pattern into multiple output light patterns, where one output light pattern is determined from the multiple output light patterns based on the modification applied to the optically active cellulose film. Thus, the optically active cellulose film may exhibit the function of detecting the modification applied to the optically active cellulose film. The optically active cellulose film can be used in a variety of applications, including, but not limited to, sensors such as humidity sensors, color selection of greenhouse films, increased light scattering of greenhouse films, biodegradable diffraction elements, polarization-based light filtering, polarization-based sensors, laser beam steering by heating or wavelength tuning where the angle of the laser beam depends on temperature or wavelength, and collimation and / or dispersion of microlensing light by color filtering of diffraction gratings.

[0014] Cellulosic films may be polymer cellulose, fibrillated cellulose, or fibrous cellulose films. Nanofibrillated cellulose films may refer to fibrillated cellulose films containing cellulose fibers with nanoscale diameters and a narrow fiber size distribution. Similarly, nanofiber cellulose films may refer to fibrous cellulose films containing cellulose fibers with nanoscale diameters and a narrow fiber size distribution. Examples of cellulose films include cellulose nanofiber (CNF) films, nanofibrillated cellulose films, and TEMPO-oxidized CNF (TEMPO-CNF) films. Cellulosic films are used in the packaging industry, electronic equipment, and diagnostics. CNF may be produced from the mechanical decomposition of commercially available bleached hardwood kraft pulp. TEMPO-oxidized cellulose nanofibers (TEMPO-CNF) may be produced from dried, bleached softwood kraft pulp. The softwood kraft pulp may be TEMPO-oxidized, with oxidation mediated by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radicals. TEMPO oxidation may also be carried out according to the protocol described in "Homogeneous Suspensions of Individualized Microfibrils from TEMPO-Catalyzed Oxidation of Native Cellulose" by Saito et al., Biomacromolecules, 2006, 7(6), pp. 1687-1691, DOI:10.102 l / bm060154s, published May 3, 2006. Further details on the preparation of CNF and TEMPO-CNF films may be found in Section 2.1 of Makela et al., referenced below.

[0015] An optically active cellulose film may be configured to receive light and to output an output light pattern by splitting and refracting or splitting the received light. The light may be received from a light-emitting diode (LED), a light bulb, a laser, or other form of light source which may have a color that facilitates interaction with the user in a particular environment, for example. The optically active cellulose film may be configured to split and refract or splitting the received light into a plurality of output light patterns. Splitting and refracting the received light includes the light received by the optically active cellulose film being transmitted at least partially through the optically active cellulose film. The light output by the optically active cellulose film is then refracted and split into two or more color components. Splitting and reflecting the received light includes the light received by the optically active cellulose film being reflected at least partially by the optically active cellulose film. The light output by the optically active cellulose film is then reflected and split into two or more color components. One of the plurality of output light patterns may be determined based on modifying the optically active cellulose film to cause a change in the properties of the optically active cellulose film. Since segmented refraction or segmented reflection is controlled by changes in the properties of the optically active cellulose film, the output light pattern of the optically active cellulose film may be determined based on the modification.

[0016] Modification of an optically active cellulose film may be determined based on a comparison of one or more output light patterns or a comparison of data representing one or more output light patterns. Therefore, it should be understood that, instead of output light patterns, data representing output light patterns may also be sufficient to determine the modification in various examples and embodiments described herein. In one example, one or more preceding output light patterns may be compared with one or more subsequent output light patterns. Since a comparison of the shape and / or position of one or more preceding output light patterns with the shape and / or position of one or more subsequent output light patterns may be used to determine one or more changes in the output light patterns, at least one modification of the optically active cellulose film may be determined based on the difference in shape and / or position between at least the subsequent output light patterns and the preceding output light patterns. In one example, modification of an optically active cellulose film causes a change in the properties of the optically active cellulose film. Examples of properties of an optically active cellulose film include, at a minimum, a change in the dimensions of the three-dimensional (3D) structure of the surface pattern of the optically active cellulose film and a change in the refractive index of the optically active cellulose film. Changes in dimensions and / or refractive index may cause changes in one or more preceding output light patterns, and a comparison of the preceding and succeeding output light patterns may be used to determine the modification of the optically active cellulose film. Examples of modification of the optically active cellulose film include exposure of the optically active cellulose film to at least one or more of the following: water, ultraviolet (UV) light, radiation, temperature, strain, and other materials or molecules arranged in the surface pattern of the optically active cellulose film.

[0017] An example of an output light pattern is a geometric pattern. The light may be divided into color components that form the output light pattern. The light may be monochromatic, such as laser light, or it may contain one or more colors, such as white light.

[0018] The surface pattern of the optically active cellulose-based film may include a micro / nano-scale three-dimensional (3D) structure, such as pillars or gratings. Therefore, the dimensions of the structure, such as height, width, depth, and diameter, may vary from the nanometer scale to the micrometer scale.

[0019] The cellulose fibers of the optically active cellulose-based film may be aligned in the same direction. It should be understood that due to this alignment, the optically active cellulose-based film has polarization sensitivity and birefringence, so the refractive index varies depending on the direction.

[0020] The microlens may refer to an optically active cellulose-based material configured to enhance the collimation, dispersion, and / or filtering of light.

[0021] Figures 1a, 1b, 2a, and 2b show the surface patterns of optically active cellulose-based films according to at least some embodiments of the present invention. The surface pattern provides that the optically active cellulose-based film may split-refract or split-reflect light to generate an output light pattern. As shown in Figures 1a and 1b, the surface pattern of the optically active cellulose-based film 100 includes micro / nano pillars 102. As shown in Figures 2a and 2b, the surface pattern of the optically active cellulose-based film 200 includes a micro / nano grating 202, i.e., a diffraction grating. As shown in Figures 1b and 2b, the optically active cellulose-based film includes one or more microlenses 104, 204. The microlenses may be integrated into the optically active cellulose-based film to enhance the collimation, dispersion, and / or filtering of light.

[0022] In one example, the microlenses 104, 204 may be disposed on one or both sides of the optically active cellulose-based film. When disposed on one side of the optically active cellulose-based film, the light entering and exiting the optically active cellulose-based film is collimated or dispersed by the microlenses. On the other hand, when disposed on both sides of the optically active cellulose-based film, the light entering and exiting the optically active cellulose-based film may be collimated and / or dispersed by the microlenses.

[0023] In one example, the microlenses 104, 204 may be disposed on the same film as the optically active cellulose-based film and / or on a separate film. When the microlenses are disposed on a separate film, the microlenses may be laminated on one or both sides of the optically active cellulose-based film.

[0024] In one example according to at least some embodiments, the absorption of water into the optically active cellulose-based films 100, 200 causes a change in the size of the surface pattern. In one example, the dimensions of the pillars 102 or the diffraction grating 202 may change.

[0025] In one example, optically active cellulose films 100, 200 containing micro / nanopillars are manufactured using nanoimprint lithography (NIL), also known as hot embossing. NIL is a process for replicating microscale and nanoscale patterns. NIL is an efficient method for fabricating large-area nanopatterns and micropatterns on various materials, typically thermoplastics. For more information on nanoimprint lithography, see SYChou, PRKrauss, PJRenstrom, Nanoimprint lithography, J.Vac.Sci.Technol.B, 14(6)(1996), pp. 4129-4133. Hot embossing is described, for example, in Micro hot embossing of thermoplastic polymers: a review, Linfa Peng et al., 2014, J.Micromech.Microeng.24 013001.

[0026] The production of optically active cellulose-based films 100 and 200 using roll-to-roll (R2R) nanoimprint lithography brings high productivity to many industrial-scale applications. "Fabrication of micropillars on nanocellulose films using a roll-to-roll nanoimprinting method" (Tapio Makela et al., Microelectronic Engineering, Vol. 163, September 1, 2016, pp. 1-6) discloses a method for producing microstructured films by modifying bio-based cellulose-based films with thermal roll-to-roll nanoimprint lithography (R2RNIL). In NIL, a patterned roll and an elastic backing roll are pressed against each other at high temperatures, and the pattern is replicated in the film structure. The height of the replicated pattern is controlled by the temperature, printing speed (contact time with the film), and pressure applied to the R2RNIL.

[0027] In one embodiment, the optically active cellulose films 100 and 200 are films of polymer cellulose, fibrillated cellulose, or fibrous cellulose, cellulose nanofibers, CNF, preferably TEMPO-oxidized cellulose nanofibers (TEMPO-CNF).

[0028] As shown in Figure 3, a method is provided to support the detection of modifications to optically active cellulose films without the use of moving parts. In one example, the method may be performed by an apparatus including an optical position sensor device. Step 302 includes splitting refraction or splitting reflection of light received by a surface pattern of the optically active cellulose film into a plurality of output light patterns, one of which is determined from the plurality of output light patterns based on the modifications applied to the optically active cellulose film. Since the splitting refraction or splitting reflection is controlled by the modifications to the optically active cellulose film, the modifications applied to the optically active cellulose film may be determined based on the output light pattern or changes in data indicating the output light pattern.

[0029] In one example, step 302 includes modifying the optically active cellulose film by exposing it to water. The optically active cellulose film may be exposed to water, for example, by increasing the ambient humidity of the optically active cellulose film. The ambient humidity may be increased, for example, by water vapor. When the optically active cellulose film is exposed to water, the water is absorbed by the optically active cellulose film, thus increasing the humidity level of the optically active cellulose film. In one example, the increased humidity of the optically active cellulose film changes the dimensions of the surface pattern of the optically active cellulose film, for example, the optically active cellulose film swells, so the segmental refraction and segmental reflection performed by the optically active cellulose film are modified, and the output light pattern changes.

[0030] In one embodiment, in step 302, the optically active cellulose film includes one or more microlenses for collimation, dispersion, and / or filtering of light of one or more colors received by the surface pattern. The microlenses may be arranged on one or both sides of the optically active cellulose film for collimation, dispersion, and / or filtering of the light of one or more colors received.

[0031] In one example, step 302 includes the output light pattern corresponding to the humidity level. In one example, the output light pattern may change depending on the humidity of the optically active cellulose film. If absorbed water changes the dimensions of the surface pattern of the optically active cellulose film, the output light pattern may change depending on the humidity.

[0032] In one example, step 302 includes the change in the output light pattern including the movement of the output light pattern and / or the broadening of the color spectrum.

[0033] As shown in Figure 4, a method is provided using an apparatus including an optical position sensor device. Step 402 includes capturing data from an optically active cellulose film located within the field of view of the optical position sensor device. The optically active cellulose film includes a surface pattern configured to split-refract or split-reflect the received light into a plurality of output light patterns, one of which is determined from the plurality of output light patterns based on a modification applied to the optically active cellulose film. Step 404 includes determining the modification applied to the optically active cellulose film based on captured data showing a change in one or more output light patterns in response to the modification applied to the optically active cellulose film. In one example of modification, the absorption of water into the optically active cellulose film causes a change in the dimensions of the surface pattern of the optically active cellulose film. Since the change in the surface pattern causes a change in the output light pattern, the modification may be determined to be the humidity level of the optically active cellulose film or a changed humidity level. Thus, the optically active cellulose film may be used by an apparatus that functions as a humidity sensor.

[0034] In one embodiment, step 404 includes the output light pattern corresponding to different humidity levels. In one example, the output light pattern may vary depending on the humidity. Examples of different humidity levels include at least 0% to 100%, preferably 0% to substantially 70%, or at least nearly 70%, for observing a linear change in the output light pattern. On the other hand, examples of different humidity levels for applications where a relatively high change in the output light pattern is preferred, such as for an ON / OFF sensor for detecting any or at least a majority modification of the output light pattern, include 70% to 99%. In one example, if absorbed water changes the dimensions of the surface pattern of an optically active cellulose film, the output light pattern may vary depending on the humidity.

[0035] In one example, step 404 includes determining a change in the output light pattern based on the movement of the output light pattern and / or the spread of the color spectrum in response to the modification.

[0036] In one example, step 402 includes an optical position sensor device being a digital camera that performs a camera application and generates a still image of an optically active cellulose film located within the camera's field of view. The camera application may be performed continuously to generate still images. Alternatively, the camera application may be performed discontinuously based on an application trigger, for example, by a timer or other conditions. It may be sufficient to determine the modification in a single image, provided that the camera has an exposure time long enough to capture changes in the output light pattern.

[0037] In one example, step 402 includes an optical position sensor device being a digital camera that performs a camera application and generates video clips of an optically active cellulose film located within the camera's field of view. The video provides continuous monitoring of the modification so that the time of modification is precisely determined.

[0038] As shown in Figure 5, a method is provided using an apparatus including an optical position sensor device. This method may be performed, for example, after step 404, in relation to the method in Figure 4. Step 502 includes performing at least one user interface action in response to the determined modification. The user interface action may notify the user of the determined modification of the optically active cellulose film by providing interaction (dialogue) with the user through the user interface. Thus, the user does not necessarily need to observe changes in the output light pattern, but the user interface action still allows them to know about the modification. It should be understood that the user interface provides notification of the modification to the user, in particular when the user does not have knowledge of how to interpret the output light pattern, and / or when the output light pattern or its changes are invisible to the human eye. In one example, the duration of the user interface action may be a time-limited user interface action, a semi-permanent user interface action, or a permanent user interface action. In one example, a time-limited user interface action may be an audio recording played for a relatively short time after the optically active cellulose film has been modified. In one example, a semi-permanent user interface action may be a sound that stops after the user inputs a voice confirmation into the user interface. In another example, a permanent user interface action may be a sound that is played continuously. Although the above examples use sound as an example, other user interface actions may be used as alternatives or additional actions. Further examples of user interface actions include the display of information and / or the illumination of lights. Examples of displayed information include user interface elements that may include graphics, text, or a combination thereof. Lights may be light-emitting diodes (LEDs), light bulbs, lasers, or other forms of light sources that may have a color that facilitates interaction with the user in a particular environment of the device.

[0039] Figure 6 shows a change in the surface pattern according to at least some embodiments of the present invention. Step 602 includes exposing the optically active cellulose film 604, which includes the surface pattern 606, to white light 608 transmitted through the optically active cellulose film. The surface pattern causes the white light to split and refract into an output light pattern 611 on the detector 610. Step 612 includes applying one or more modifications to the optically active cellulose film by exposing it to water, ultraviolet (UV) light, radiation, temperature, strain, and other materials or molecules arranged in the surface pattern of the optically active cellulose film. Thus, the surface pattern 606 may be changed, and a new surface pattern 616 may be generated. Step 614 includes exposing the optically active cellulose film 604, which includes the new surface pattern 616, to white light 608 transmitted through the optically active cellulose film. The new surface pattern causes the white light to split and refract into a new output light pattern 618 on the detector 610. Therefore, applying one or more modifications to an optically active cellulose-based film causes a change in the output light pattern 611.

[0040] In one example, the output light patterns 611 and 618 include distinct regions of different colors on the detector. The colors may include red, green, and blue light. After the optically active cellulose film is modified, the output light pattern 611 changes. Following the arrow next to the detector 610, the modification of the optically active cellulose film may cause the output light pattern 611 to move downward, thereby generating a new output light pattern 618. It should be understood that the detector may be planar, but can also be non-planar. Therefore, the output light pattern may move on the surface of the detector, at least in the direction in which the surface of the detector extends. It should be understood that an image or video captured by a digital camera may function as a detector.

[0041] The changes in surface patterns are shown in Figure 7 in conjunction with the explanation of segmental refraction, but it should be understood that, according to at least some embodiments, one or more output light patterns may be caused by an optically active cellulose-based film that segmentally reflects light.

[0042] Figure 7 shows a block diagram of an apparatus according to at least some embodiments of the present invention. The apparatus includes an optical position sensor device 702 for capturing data, a processor 704, a memory 706, and a user interface 708, which may be operably connected to produce one or more functions described herein. The connections between the optical position sensor device, the processor, the memory, and the user interface may be realized, for example, by conductors on a circuit board.

[0043] The data captured by the optical position sensor device may include at least information indicating the position of a light pattern or the position of part of a light pattern. This data allows for the detection of changes in the output light pattern of an optically active cellulose film. In one example, the data may include one or more images or videos. The images or videos may be digital images and videos generated by the optical position sensor device, for example, a digital camera.

[0044] In one embodiment, the processor 704 controls an optical position sensor device 702 to capture data from an optically active cellulose film located within the field of view of the optical position sensor device, wherein the optically active cellulose film includes a surface pattern configured to split-refract or split-reflect light into a plurality of output light patterns, and one output light pattern is determined from the plurality of output light patterns based on a modification applied to the optically active cellulose film, and the processor 704 is configured to perform the steps of determining the modification applied to the optically active cellulose film based on captured data showing changes in one or more output light patterns in response to the modification applied to the optically active cellulose film.

[0045] In one embodiment, the apparatus includes a user interface 708. The processor is configured to control the user interface to perform at least one user interface operation in response to a determined change in the surface pattern.

[0046] Memory 706 may be a separate memory. Alternatively, the memory may be included in the processor and / or optical position sensor device. Furthermore, the device may include a separate memory and a memory included in the processor and / or optical position sensor device.

[0047] An example of an optical position sensor device 702 is a device capable of generating data for detecting the position of an optical signal, including at least a digital camera, a photocell, and a light intensity sensor. The optical position sensor device may also be called a matrix detector or column detector, having detector elements in a two-dimensional array / matrix or a one-dimensional line / column. The field of view of the optical position sensor device may also be the sensitivity region of the optical position sensor device, where the optical position sensor device may capture data.

[0048] In at least some embodiments, the processor is configured to control a digital camera to capture at least one image and / or video from an optically active cellulose film located within the camera's field of view, and to determine the modifications applied to the optically active cellulose film based on at least one captured image or video showing changes in one or more output light patterns in response to the modifications applied to the optically active cellulose film.

[0049] Memory may refer to a computer-readable medium that may not be temporary. Memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. Data processors may be of any type suitable for the local technical environment and may include, in non-limiting examples, one or more of the following: general-purpose computers, dedicated computers, microprocessors, digital signal processors (DSPs), and processors based on multi-core processor architectures.

[0050] Embodiments may be implemented as software, hardware, application logic, or a combination of software, hardware, and application logic. The software, application logic, and / or hardware may reside in memory or any computer medium. In exemplary embodiments, the application logic, software, or instruction set is maintained in one of various conventional computer-readable media. In the context of this specification, “memory” or “computer-readable medium” may be any medium or means that can contain, store, communicate, propagate, or transmit instructions for use by or in connection with an instruction execution system, apparatus, or device such as a computer.

[0051] Where relevant, please understand that references such as "computer-readable storage medium," "computer program product," "tangibly embodied computer program," or "processor" or "processing circuit" encompass not only computers with different architectures such as single / multiprocessor architectures and serial / parallel architectures, but also specialized circuits such as field-programmable gate arrays (FPGAs), application-specific circuit ASICs, signal processing devices, and other devices. Please understand that references such as computer-readable program code means, computer programs, computer instructions, and computer code represent instructions for a processor, or software for programmable processor firmware as configured or configurable settings for fixed-function devices, gate arrays, programmable logic devices, etc., such as programmable content for hardware devices.

[0052] In general, various embodiments of the present invention may be implemented in hardware, dedicated circuits, or any combination thereof. While various aspects of the present invention may be illustrated and described using block diagrams or several other graphical descriptions, it should be fully understood that these blocks, devices, systems, techniques, or methods described herein may be implemented, in non-limiting examples, in hardware, software, firmware, dedicated circuits or logic, general-purpose hardware or controllers, or other computing devices, or several combinations thereof.

[0053] The foregoing description, by illustrative and non-limiting examples, has provided a complete and useful explanation of exemplary embodiments of the present invention. However, when read in conjunction with the accompanying drawings and claims, various modifications and variations may become apparent to those skilled in the art. However, all such and similar modifications of the teachings of the present invention remain within the scope of the invention.

Claims

1. An apparatus comprising an optical position sensor device for capturing data and a processor, wherein the processor is A step of controlling the optical position sensor device to capture data from a cellulose nanofiber (CNF) film located within the field of view of the optical position sensor device, wherein the CNF film includes a surface pattern configured to split-refract or split-reflect the received light into a plurality of output light patterns, and one output light pattern is determined from the plurality of output light patterns based on the absorption of water into the CNF film. A step of determining the absorption of water into the CNF film based on captured data showing changes in one or more output light patterns in response to the absorption of water into the CNF film. A device configured to perform the following actions.

2. The system includes a user interface, and the processor is configured to control the user interface to perform at least one user interface action to notify the user in response to the determined water absorption. The apparatus according to claim 1.

3. The CNF film is a film of TEMPO-oxidized cellulose nanofibers and TEMPO-CNF. The apparatus according to claim 1 or 2.

4. A step of capturing data from a cellulose nanofiber (CNF) film located within the field of view of an optical position sensor device, wherein the CNF film includes a surface pattern configured to split-refract or split-reflect the received light into a plurality of output light patterns, and one output light pattern is determined from the plurality of output light patterns based on the absorption of water into the CNF film. A step of determining the absorption of water into the CNF film based on captured data showing changes in one or more output light patterns in response to the absorption of water into the CNF film. Methods that include...

5. The process includes the step of performing at least one user interface action to notify the user in response to the determined water absorption, The method according to claim 4.

6. The output light pattern corresponds to different humidity levels of the CNF film. The method according to claim 4 or 5.

7. A cellulose nanofiber (CNF) film comprising a surface pattern configured to split and refract or split and reflect received light into a plurality of output light patterns, A CNF film wherein the surface pattern includes dimensions and refractive index of a three-dimensional (3D) structure for determining an output light pattern from a plurality of output light patterns, wherein the dimensions and / or refractive index of the three-dimensional (3D) structure are configured to change in response to the absorption of water into the CNF film, thereby changing the output light pattern based on the absorption of water into the CNF film.

8. Includes one or more microlenses for collimation, dispersion and / or filtering of light of one or more colors received by the surface pattern, The CNF film according to claim 7.

9. The process includes the step of splitting and refracting or splitting and reflecting light received by a surface pattern of a cellulose nanofiber (CNF) film into multiple output light patterns, A method for changing the output light pattern based on the absorption of water into the CNF film, wherein the surface pattern includes dimensions and refractive index of a three-dimensional (3D) structure for determining an output light pattern from a plurality of output light patterns, the dimensions and / or refractive index of the three-dimensional (3D) structure are configured to change in response to the absorption of water into the CNF film.

10. The output light pattern corresponds to different humidity levels of the CNF film. The method according to claim 9.

11. Light of one or more colors received by the surface pattern is collimated, dispersed, and / or filtered by one or more microlenses positioned on at least one side of the CNF film. The method according to claim 9 or 10.

12. Color selection of the output light pattern, Control of light scattering, The step of absorbing water into the CNF film in order to induce one or more of the following: wavelength tuning and laser beam steering, The method according to any one of claims 9 to 11.

13. The CNF film is a film of TEMPO-oxidized cellulose nanofibers and TEMPO-CNF. The method according to any one of claims 9 to 12.

14. A step of capturing at least one image or video from a cellulose nanofiber (CNF) film located within the field of view of an optical position sensor device, wherein the CNF film includes a surface pattern configured to split-refract or split-reflect the received light into a plurality of output light patterns, and one output light pattern is determined from the plurality of output light patterns based on the absorption of water into the CNF film. A step of determining the absorption of water into the CNF film based on captured data showing changes in one or more output light patterns in response to the absorption of water into the CNF film. A computer program comprising computer-readable program code means adapted to perform at least the following:

Images