Optical incoupling tape, light guide using the same, and method for manufacturing the same

Abstract

This technology provides optical incoupling that efficiently introduces light emitted from an emitter device into a light guide medium, establishing a stable light propagation path through internal total internal reflection. [Solution] The present invention relates to an optical incoupling tape 50 arranged such that light 31 emitted from an emitter device 30 is incident on a light guide medium 20 before it is incident on the light guide medium 20, comprising a substrate and at least one periodic pattern including a plurality of optical functional cavities embedded in the material of the substrate. The optical functional cavities are filled with a material having a different refractive index than the material of the surrounding substrate and are configured to incouple the incident light 31 and adjust its direction. As a result, the incoupled light 32 obtains a light propagation path through the light guide medium 20 via a series of internal total internal reflections.

Description

[Technical Field]

[0001] The present invention generally relates to providing optical structures for waveguides and methods for manufacturing them. In particular, the present invention relates to flexible solutions, related methods and uses, based on integrated cavity optical systems configured to incouple outgoing light into an optical waveguide and to control the distribution of light propagation through the waveguide. [Background technology]

[0002] Optical waveguide or light guide technology is widely used in a variety of cutting-edge applications. The appropriate selection of the light distribution system often determines the illumination performance of optical waveguides in lighting and display applications. A typical light guide (LG) system includes components for edge-incoupling light rays emitted from one or more emitters, components for distributing light through light guide elements, and components or regions for light extraction (outcoupling). The incoupling structure receives light and adjusts its direction to guide the light rays into the distribution region. Advanced light guides feature optical patterns that control the optical edge-incoupling efficiency of light upon incidence into the light guide.

[0003] Conventional light guide solutions designed for illumination applications still utilize multiple separate optical films for optical outcoupling, such as brightness enhancement films (BEFs), to control the angular distribution of emitted light and achieve desired optical performance. Known light guide solutions implemented without BEFs typically employ microlenses and V-groove-shaped optical patterns. It is impossible to achieve the desired, perfectly controlled illumination distribution using such solutions. Optical incoupling typically occurs at the edges of the light guide without advanced optical solutions. In some special cases, such as in augmented reality and virtual reality headsets, planar incoupling is used based on surface relief gratings incorporated into the light guide elements.

[0004] Angulo Barrios and Canalejas-Tejero[1] This paper discloses an optical coupling solution in a flexible Scotch tape waveguide obtained via an integrated metal diffraction grating. An incoupling grating and an outcoupling grating are embedded inside the two layers of the Scotch tape, allowing the Scotch tape to function as an optical waveguide. The gratings are implemented as a metal (Al) nanohole array (NHA) grating.

[0005] US 2015 / 192742 A1 (Tarsa and Durkee) discloses a light extraction film laminated to the surface of a light guide. The light extraction function is based on TIR (Total Internal Reflection). When the extraction film is fixed to the light guide by lamination or other means, an air pocket is formed between the film and the light guide.

[0006] US 2018 / 031840 A1 (Hofmann et al.) discloses an optical element with an embedded optical grating for extracting light from a light guide. The surface of the grating is coated with an optically effective layer using known methods such as chemical vapor deposition (CVD) or physical vapor deposition (PVD). Furthermore, recesses present in the grating are filled with optical cement or optical adhesive material.

[0007] US 10,598,938 B1 (Huang and Lee) discloses an angle-selective oblique grating coupler for controlling the angle at which light is outcoupled from or incoupled to a light guide. Selectivity can be achieved by modulating the refractive index between gratings or by modulating the duty cycle of the gratings in different regions.

[0008] Kress[2] discloses in-couplers and out-couplers for optical waveguides, the couplers comprising different types of gratings configured for transmission and / or reflection functions. The couplers are sandwiched / embedded in a light guide or provided as a surface relief solution.

[0009] Moon et al. [3] disclose an outcoupler that uses a microstructured hollow (air) cavity grating to improve light extraction from an LED device. The hollow cavity is fabricated in a semiconductor material in a typical manner. Apart from LEDs, no other applications of the outcoupler solution have been provided (e.g., in light guides).

[0010] The design and optimization of light guide-based lighting solutions face specific challenges related to non-uniform light distribution within the light guide, insufficient incoupling and outcoupling, and light trapping and / or extraction efficiency. Furthermore, the aforementioned solutions have limitations in that they cannot provide a flexible, integrated air cavity optics-based solution with satisfactory versatility and adaptability for a variety of target applications, such as large window lighting with planar light incoupling.

[0011] In this regard, improvements in the field of optical structures for non-fiber optic light guides (aimed at increasing brightness uniformity and improving the optical efficiency of the light guides) remain desirable, in order to address the challenges associated with the manufacturing and assembly of current existing solutions. [Overview of the Initiative]

[0012] The object of the present invention is to at least mitigate the problems arising from the limitations and drawbacks of the related technology. This object is achieved by various embodiments of the optical incoupling tape according to the definition of independent claim 1.

[0013] In one embodiment, an optical incoupling tape for a light guide is provided. The optical incoupling tape comprises a substrate and a pattern formed of a number of periodic pattern features embedded in the substrate material and configured as optical function embedding cavities, wherein the optical function embedding cavities are filled with a material having a refractive index different from that of the substrate material surrounding the cavities. In the tape, the pattern is configured to incouple incident light and adjust the direction of the incoupled light so that the incoupled light obtains a propagation path through a light guide medium via a series of internal total internal reflections. The tape is detachable from at least one plane of the light guide so as to form an optical contact for light transmission between the tape and the light guide medium.

[0014] In the embodiment, the optical incoupling tape is configured such that the incoupling light is redirected at the interface between each cavity and the material of the substrate surrounding the cavity to obtain the propagation path through the light guide medium, and the angle of incidence at the interface between the light guide medium and the surroundings, and optionally, the angle of incidence at the interface between each cavity and the material of the substrate surrounding the cavity, is greater than or equal to the critical angle of internal total internal reflection.

[0015] In an embodiment, at least one pattern in the tape is configured to perform an optical function related to adjusting the incoupling and direction of received light, the optical function being selected from the group consisting of reflection, absorption, transmission, collimation, refraction, diffraction, polarization, and any combination thereof.

[0016] In an embodiment, in the tape, the pattern is made optically functional by providing cavities or a group of cavities in the pattern with a number of parameters, and the number of parameters is composed of any combination of parameters selected from the group consisting of dimensions, shapes, cross-sectional profiles, orientations, periodicities, and fill factors.

[0017] In an embodiment, each individual cavity in the pattern has a number of optically functional surfaces. In an embodiment, the optically functional surface(s) is established by any surface(s) formed at the interface between each cavity and the material of the substrate surrounding the cavity. In an embodiment, the optically functional surface(s) in each individual cavity in the pattern is established by any one of a low refractive index reflector, a polarizer, a diffuser, an absorber, or any combination thereof.

[0018] In an embodiment, the optical in-coupling tape further comprises a wavelength conversion layer.

[0019] In different embodiments, in the tape, the cavities are configured and arranged in the pattern so as to form a substantially variable periodic pattern or a substantially constant periodic pattern.

[0020] In an embodiment, in the pattern, the cavities are established by discrete or at least partially continuous pattern features.

[0021] In an embodiment, the optical in-coupling tape comprises a number of patterns arranged as periodic segments, and each segment has a predefined area and a periodic length.

[0022] In an embodiment, the pattern in the tape is variably configured by a number of cavity-related parameters, and the number of cavity-related parameters is composed of individual parameters or any combination of parameters selected from the group consisting of dimensions, shape, cross-sectional profile, orientation, position, periodicity, and fill factor.

[0023] In an embodiment, the cavity is established by a two-dimensional or three-dimensional pattern feature having a cross-sectional profile selected from the group consisting of linear, rectangular, triangular, blazed, inclined, trapezoidal, curved, wavy, and sinusoidal profiles.

[0024] In an embodiment, the cavity is filled with a gaseous material such as air.

[0025] In an embodiment, the optical in-coupling tape is configured to be attachable to the plane(s) of the light guide. The tape can be attached by adhesion.

[0026] In an embodiment, the pattern(s) includes cavities formed in the substrate provided as a substantially flat and planar substrate layer. The substantially flat and planar substrate layer in which the cavities are formed is made of a substantially optically transparent material. The pattern(s) is provided as an optically transparent layer, a reflector layer, and / or a colored layer and includes fully embedded cavities formed at the interface with an additional flat and planar substrate layer.

[0027] In an embodiment, the optical in-coupling tape is composed of a number of embedded patterns arranged in a laminated configuration.

[0028] In an embodiment, the optical in-coupling tape has a wedge structure.

[0029] In another aspect, a method is provided for manufacturing an optical incoupling tape having at least one pattern formed by a number of periodic cavity features embedded in a substrate material, according to the definition of independent claim 22.

[0030] In one embodiment, the method is - To manufacture a patterned master tool for at least one pattern by a manufacturing method selected from lithography, 3D printing, micromachining, laser engraving, or any combination thereof, -Transferring the pattern onto the substrate to produce a patterned substrate, - Applying an additional substrate layer or cover layer to the patterned substrate to generate an embedded cavity pattern (one or more) Includes, The aforementioned embedded cavity pattern(s) includes a cavity configured as an optically functional cavity, which is filled with a material having a refractive index different from that of the substrate material surrounding the cavity. The embedded cavity pattern is configured to incouple the incident light and adjust the direction of the incoupled light, thereby causing the incoupled light to obtain a propagation path through the light guide medium via a series of internal total internal reflections.

[0031] In the embodiment, the additional substrate layer is applied to the patterned substrate layer by a lamination method selected from roll-to-roll lamination, roll-to-sheet lamination, or sheet-to-sheet lamination.

[0032] In embodiments, the method includes duplicating the fabricated pattern, the pattern duplication method being selected from imprinting, extrusion duplication, or 3D printing.

[0033] In another aspect, a light guide is provided according to the definition of independent claim 25. The light guide comprises an optically transparent medium configured to establish a path for light propagation through the light guide, and an optical incoupling tape in any of the aforementioned aspects, wherein the optical incoupling tape is attached to at least one plane of the light guide.

[0034] In one embodiment, the light guide includes the optical incoupling tape which is attached thereto by adhesive.

[0035] In another aspect, the use of the light guide in illumination and / or display according to the definition of independent claim 27 is provided.

[0036] In a further aspect, a roll of optical incoupling tape is provided, wherein the optical incoupling tape is mounted in any of the aforementioned aspects, according to the definition of independent claim 28.

[0037] In another further aspect, an optical unit is provided according to the definition of independent claim 29. The optical unit comprises an optical incoupling tape having an adhesive layer for attaching a light guide, and at least one emitter device.

[0038] In the embodiment, the at least one emitter device is selected from the group consisting of light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), laser diodes, LED bars, OLED strips, microchip LED strips, and cold cathode tubes.

[0039] In one embodiment, the optical unit comprises at least one optical emitter device configured to emit monochromatic light, and the optical incoupling tape including the wavelength conversion layer.

[0040] The usefulness of the present invention arises for various reasons, depending on each specific embodiment. First, the present invention relates to a novel optical tape solution configured to incouple photons of optical radiation (light) emitted by at least one emitter device, and to adjust the direction of the incooled rays, thereby mediating light propagation through a light guide medium. The optical tape according to the present invention is advantageous in that it is designed for planar, non-fiber type light guides.

[0041] One of the key advantages provided by the optical incoupling tape according to the present invention is the incoupling of light to a planar light guide surface(s). Thus, the tape incouples light rays arriving at the planar light guide surface from any direction, enabling efficient capture of the light rays within the planar light guide. At the same time, the tape adjusts the direction of the incoupled light so that the light rays remain inside the light guide (preventing light leakage). In particular, the tape of this disclosure enables the incoupling of light to large (planar) window panes, which was not possible with conventional solutions for incoupling light from the edge of a window.

[0042] Known incoupling solutions are typically fixed solid structures located inside light guides, which, for the reasons mentioned above, prevent their efficient use on pre-installed window surfaces. From a manufacturing standpoint, such fixed incoupling structures are not suitable for mass production, such as by etching them into window glass installed in buildings. Furthermore, the aforementioned fixed solutions do not allow for the combination of different optical functionalities within the same incoupling structure.

[0043] The incoupling tapes presented herein offer greater flexibility in positioning the light source. The optical emitter can be integrated into the tape or mounted on the tape. Alternatively, the emitter can be positioned at a distance from the tape to avoid the optical incoupling tape and light guide receiving thermal energy (for example, in the case of a laser light source).

[0044] A tape, configured to be attachable to at least one surface of the optical element, for example by an adhesive layer, controls the incoupling and further propagation of emitted light within the optical medium (i.e., light guide medium). Incident light incoupled to the tape pattern(s) is deflected by an angle from its original propagation path by an (air) cavity optical system embedded within the tape. The fully integrated and embedded cavity optical system is based on a two-dimensional or three-dimensional pattern matrix to achieve desired light control by profile configuration, and the three-dimensional pattern matrix may consist of a single profile or multiple profiles.

[0045] The tape is configured to couple incident light from an emitter device located outside the tape. It can efficiently (in)couple light incident at a wide range of angles of incidence. Therefore, the tape can at least incouple and redirect incoupled light within the optical element (light guide).

[0046] The tape is extremely easy to install, offering flexibility for removal, modification, and reinstallation to the desired location. The optical structure(s) within the tape are protected from external conditions, ensuring high reliability. Improved incoupling efficiency and enhanced light distribution control also improve the characteristics of the outcoupling light.

[0047] The optical incoupling tape according to this disclosure is easy to use and highly reliable due to its embedded cavity optics. The embedded cavity optics, due to their internal properties, are not damaged or malfunctioned by normal handling procedures, including assembly and cleaning. In its ready-to-use state, the tape has no surface relief pattern formed on its surface. Because the tape has an overall flat and planar outer surface, it can be touched and cleaned without altering or impairing its optical performance. The tape can be easily attached to the relevant optical element, for example, by an adhesive surface, either manually or automatically.

[0048] The flexible tape solution can be configured with any desired combination of size-related parameters (length × width × thickness / height). The tape can be easily applied to any surface of the light guide, for example, any side and / or edge(s).

[0049] In several preferred embodiments, the solutions provided herein are advantageously realized as an integrated (internal) cavity optical system. In conventional solutions with optical cavities, light is often transmitted through (penetrates) the cavity, causing undesirable refraction and preventing the achievement of light distribution control. In contrast, the solutions provided herein allow for high-precision control of the light distribution (i.e., refraction angle and direction) of the extracted light through the TIR function of the corresponding optical functional feature pattern.

[0050] The optical design of the optical incoupling tape may be constant, and the optical pattern solution may be based on a similar, continuous, repeating pattern that includes periodic features. Alternatively, the tape may have a continuously changing pattern or segmented pattern, with each local pattern design pre-defined for a characteristic incidence angle or range of incidence angles. Naturally, the solution is designed and optimized for a specific light guide thickness and other specific parameters.

[0051] One of the primary objectives of the optical incoupling tape according to the present invention is to improve the functionality of optical elements such as light guides to which the tape is adhered. The incoupling tape can be used alone or in combination with an optically harmonic (polarizing) tape. Placing both the incoupling tape and the optically polarizing tape on the same light guide element is beneficial for optimizing optical performance.

[0052] The terms “optical radiation” and “light” are used mostly as synonyms unless explicitly stated otherwise, and refer to electromagnetic radiation within specific parts of the electromagnetic spectrum, covering ultraviolet (UV) radiation, visible light, and infrared radiation. In some cases, visible light is preferred.

[0053] In its broadest sense, this disclosure uses the terms “light guide,” “waveguide,” or “ An optical waveguide refers to a device or structure configured to transmit light along it (for example, from a light source to a light extraction surface). This definition includes any type of light guide, including but not limited to light pipe-type components, light guide plates, and light guide panels.

[0054] The expression "a number of" in this specification refers to any positive number starting from 1. This refers to an integer, such as 1, 2, or 3. On the other hand, the expression "a plurality of" in this specification refers to any positive integer starting from 2, such as 2, 3, or 4.

[0055] The terms “first” and “second” are not intended to indicate any order, quantity, or importance, but rather are simply used to distinguish one element from another. [Brief explanation of the drawing]

[0056] Different embodiments of the present invention will become apparent from the detailed description and accompanying drawings. [Figure 1A] This is a cross-sectional view of a light guide having an optical incoupling tape 50 according to an embodiment. [Figure 1B] This is a cross-sectional view of a light guide having an optical incoupling tape 50 according to an embodiment. [Figure 1C] This figure shows an optical device (unit) equipped with an incoupling tape 50. [Figure 2] These are various configurations (cross-sectional views) for using the incoupling tape 50 on the light guide. [Figure 3] This is a cross-sectional view of the incoupling tape 50 according to the embodiment. [Figure 4] This figure shows embedded cavity patterns of incoupling tapes 50 having different fill factors according to an embodiment. [Figure 5] This graph shows the incooled light intensity relative to the position of the light source collimation and the patterns with different fill factors shown in Figure 4. [Figure 6] This describes a similar arrangement to that shown in Figure 4, but the embedded pattern has a cavity feature containing a low refractive index material. [Figure 7] This graph shows the incoolation light intensity with respect to the position of the light source collimation and the pattern shown in Figure 6. [Figure 8] This figure shows embedded cavity patterns of incoupling tape 50 having different fill factors according to another embodiment. [Figure 9] This graph shows the incooled light intensity relative to the position of the light source collimation and the patterns with different fill factors shown in Figure 8. [Figure 10] This is a cross-sectional view of an incoupling tape 50 having an embedded cavity pattern according to an embodiment. [Figure 11A]This shows a light guide element with a collimated light source to which an incoupling tape 50 has been attached. [Figure 11B] This shows a light guide element with a collimated light source to which an incoupling tape 50 has been attached. [Figure 12] This is a cross-sectional view of a tape according to several embodiments. [Figure 13A] This diagram illustrates the use of an incoupling tape 50 and a combination of an optical unit 150 and an optically harmonic tape 10 utilizing the same. [Figure 13B] This diagram illustrates the use of an incoupling tape 50 and a combination of an optical unit 150 and an optically harmonic tape 10 utilizing the same. [Modes for carrying out the invention]

[0057] Detailed embodiments of the present invention are disclosed herein with reference to the accompanying drawings. The same reference numerals are used throughout the drawings to refer to the same component. The following references are used for the components.

[0058] Optical incoupling tape having base material 50A 51-Pattern 52- Optical (pattern) feature area / cavity having optical functional surfaces 521, 522 53-Contact Area 54. Shaped outer surface of the incoupling element On tape 50: 511-Optical functional layer 511A and 511B - Patterned substrate layer and additional substrate layer, respectively. 512, 513 - Additional functional layers for Tape 50 515 - Internal functional components (layers) 10-Harmonic Tape (Control over the distribution of light propagation through a light guide) 20-Optical waveguide 21-Outcoupling Pattern 22-Support for emitter devices 30. Emitter device (light source) 31. Emitted optical radiation 32-Incoupled and / or redirected optical radiation 33. Extracted electromagnetic optical rays 150 - Optical device (unit)

[0059] Figures 1A and 1B show several basic embodiments of the optical incoupling tape in 50. Figures 1A and 1B are cross-sectional views of an optical element 20, such as an optical waveguide structure, showing the optical incoupling tape 50 (hereinafter, "tape") attached to at least one surface of the waveguide. An optical waveguide, also called a light guide, is a structure configured to direct optical radiation (light) emitted by at least one suitable emitter device 30 toward a specific area where illumination is required. The light guide is a planar (non-fiber) light guide having substantially planes (may be multiple). In a basic light guide layout (for example, shown in either Figure 1A or 1B), a top surface, a bottom surface, and two or more edge surfaces can be distinguished. The top and bottom surfaces form the horizontal planes of the light guide, while the edges extend substantially vertically between the top and bottom surfaces, with an optional but predetermined angle of inclination, along a path surrounding the waveguide element when viewed as a two-dimensional shape (i.e., a periphery). The longitudinal plane of the aforementioned planar light guide lies along its horizontal plane(s).

[0060] The light guide comprises a translucent carrier medium formed from an optical polymer or glass. In an exemplary embodiment, the light guide (carrier) medium is polymethyl methacrylate (PMMA). For clarity, reference numeral 20 is used to indicate both the light guide as an entity and the carrier medium on which the light guide is made.

[0061] The tape 50 can be attached to one side or both sides (top and bottom) of a planar light guide. For example, it is reasonable to install the tape 50 on the same side of a light guide that carries other optical structures such as an optical outcoupling / extraction layer. In particular, in window lighting, due to environmental factors, it is beneficial to assemble all optical structures on the window surface facing the interior of a building or the space between stacked windows.

[0062] Figures 1A and 1B show a light guide solution in which the tape 10 is directly attached to the surface (top view, Figure 1A; bottom / back view, Figure 1B). In the configuration of Figure 1A, the emitter device 30 is positioned directly above the tape 50 which is placed on the surface of the light guide 20. In this configuration, optical radiation 31 is directly incident on the tape 50. The emitter 30 and the tape 50 are located on the same side with respect to the light guide 20.

[0063] In the configuration shown in Figure 1B, the emitter 30 is positioned approximately above the tape 50, with a light guide material 30 in between. Therefore, the tape 50 is attached to the opposite side of the light guide relative to the position of the emitter 30 (in terms of the layout in Figure 1B, the tape (The light guide is located on the underside). Thus, the optical radiation 31 reaches the tape via the light guide medium 20. The emitter can be positioned above the light guide material, as shown in Figure 1B, so that an air-light guide material interface is formed, or so that the emitter can be in contact with the light guide material.

[0064] The tape 50 can be attached to both the top and bottom / back surfaces of the light guide. In such cases, the emitter(s) 30 can be positioned in contact with either the top or back surface, or both (see Figure 6). Furthermore, tapes 50 attached to both sides may have the same / similar functions or different functions.

[0065] Figure 1C illustrates the use of an optical incoupling tape 50 in an optical device or unit 150. The unit 150 comprises the tape 50 and at least one emitter 30 configured to emit optical radiation. The emitter 30 is fully integrated into the optical unit 150. In some configurations, the emitter 30 includes a collimation device such as a collimation lens. It is advantageous that the tape and emitter are housed in a housing. Optionally, the housing is open on the side where the tape is positioned on the light guide surface. The unit 150 has a height (h) of approximately 0.5 to 10 mm, and any suitable length / width of tape 50 can be used. It is advantageous that the tape 50 includes means for light guide attachment, such as an adhesive layer.

[0066] The emitter 30 may be provided on the support portion 22. The support portion 22 may be inclined to direct the emitted (and collimated) light onto the tape at a predetermined angle (Figure 1C). The inclination angle (the angle defining the inclination of the support portion 22) may be changed depending on the design specifications and general characteristics of the optical light guide system.

[0067] The emitter(s) 30 is positioned approximately above or in contact with the tape 50 attached to the light guide surface, such that the light rays fall onto the tape at a nearly straight angle (parallel to the light guide surface normal or the tape surface normal; Figures 1A, 1B) or at a predetermined angle relative to the surface normal (Figure 1C). The surface normal is a straight line or vector perpendicular to the surface of the object (here, the light guide and the tape attached thereto, respectively). The predetermined angle is selected within the range of 10 to 90 degrees relative to the surface normal (e.g., including 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 degrees and any intermediate values). In this way, the tape 50 is configured to incouple light from the nearly top-side.

[0068] The tape 50 and unit 150 can be used with any light guide having a substantially flat surface, regardless of its thickness.

[0069] The tape 50 preferably has a uniform outer surface (the surface facing the light guide and the opposite surface). That is, it is preferable that it does not have a surface relief pattern or related structure formed thereon. More preferably, these surfaces are configured to be generally flat and planar.

[0070] In light of the technology used, embodiments of the tape 50 having a relief pattern (open cavity pattern) are not excluded.

[0071] With respect to size-related parameters (length, width, height / thickness), the tape 50 can be configured as needed to achieve optimal performance efficiency. Attachment of the tape to the light guide can be made possible or facilitated, for example, by adhesive.

[0072] Figure 2 shows various layouts of the optical incoupling tape 50 on the light guide 20 in (i) to (iv). Layout (i) is substantially the same as that shown in Figure 1A. Layouts (ii) and (iii) show the tape 50 being provided on a planar light guide medium having a conventional single-sided optical outcoupling pattern (ii) and a conventional double-sided optical outcoupling pattern 21 (iii), respectively. Layout (iv) shows the tape 50 being provided on a planar light guide medium having a single-sided or double-sided optical outcoupling pattern 21 composed of embedded cavity optics (the single-sided configuration is not specifically shown, but can be easily conceived based on iv in Figure 3).

[0073] In all options (i) to (iv), the tape 50 can be provided on one side or both sides of the planar light guide medium. Alternatively or additionally, unit 150 can be used.

[0074] The tape 50 is configured to receive and incoordinate optical radiation 31 (light) emitted from the emitter(s) 30. The tape is further configured to adjust the direction of the incoordinated light and mediate the propagation of light (rays 32) through the light guide medium toward the outcoupling region(s) 21. The extracted / outcoupled light is indicated by reference numeral 33. The optical outcoupling pattern can be integrated into the light guide medium, for example, by replication, or can be provided in the form of a coating or tape applied to the surface of the light guide.

[0075] The tape 50, attached to at least one surface of the light guide 20, forms an optical connection or optical contact for light transmission (propagation) into and through the light guide medium. When the incoupling tape is attached to the light guide, an optical contact is established at the interface between the light guide medium 20 and the tape medium (substrate 50A). The optical contact may be established via a mechanical connection or, for example, via bonding with an optically transparent adhesive.

[0076] Figure 3 shows a cross-sectional view of an optical incoupling tape 50 according to several embodiments. The incoupling tape 50 comprises a substrate 50A and at least one pattern 51 formed by a number of pattern feature portions 52 embedded in the substrate. The arrangement of the pattern feature portions 52 in the substrate material is preferably periodic, but it is not excluded to provide the pattern 51 as a non-periodic structure. The feature portions 52 are configured as optical functional cavities (i.e., internal cavity optics, embedded cavity optics, or integrated cavity optics). The latter are further referred to as "cavities" or "cavity profiles". The substrate material 50A having the embedded patterns 51 / embedded cavities 52 forms an optical functional layer 511.

[0077] The internal cavity 52 is filled with a material having a refractive index different from that of the substrate material surrounding the cavity.

[0078] In some configurations, the cavity 52 is filled with a low refractive index material. Additionally or alternatively, the cavity may have a low refractive index coating. In some configurations, the cavity 52 is filled with air to establish an embedded air cavity optical system solution. Overall, the filling material of the cavity can be established with any one of the following: a gaseous medium including air or other gases, a fluid, a liquid, a gel, and a solid.

[0079] The optical functional layer 511 having the embedded pattern 51 is formed from (sub)layers 511A and 511B. The first substrate layer 511A has a substantially flat plane in which at least one cavity pattern is formed (hereinafter referred to as the patterned layer). The patterned layer 511A may be provided as a layer of flat, planar substrate material having a uniform thickness in which at least one cavity pattern is formed. In order to establish an internal cavity and form an embedded optical pattern, the first substrate layer having the patterned surface is abutted against the entirely flat plane of the second substrate component 511B so as to form at least one embedded cavity pattern 51 having embedded cavities 52 alternating with flat bonding points or bonding regions 53 at the interface between the patterned substrate surface of the first layer 511A and the entirely flat plane of the second substrate layer 511B.

[0080] In practice, layer 511A is a substantially flat and planar substrate layer (hereinafter referred to as the patterned layer) in which a pattern(s) comprises cavities. To establish internal cavities and form an embedded optical pattern, an additional substrate layer 511B, preferably provided as a flat and planar layer overall, is positioned relative to the (patterned) layer 511A such that the internal (i.e., embedded or integrated) feature pattern 51 is established at the interface between the patterned layer 511A and the planar layer 511B. The boundary between substrate layers 511A and 511B is not shown to emphasize the substantially "integrated" nature of the optical functional layer 511 having the embedded pattern 51.

[0081] In some configurations, the second substrate layer 511B is provided as a layer of a substrate material that is uniform in thickness and is overall flat and planar.

[0082] The additional substrate layer 511B can be provided as an optically transparent layer and / or a colored layer. Layers 511A and 511B can be made from the same substrate material and / or a substrate material having substantially the same refractive index. Alternatively, these layers can be made from different materials, the differences being established at least in terms of refractive index, transparency, color, and associated optical properties (transmittance, reflectance, etc.). For example, the entire optical functional layer 511 (both layers 511A and 511B) can be made from a substantially optically transparent substrate material such as a transparent polymer or elastomer, or a UV resin. Alternatively, layers 511A and 511B can be made from different materials with different refractive indices, respectively.

[0083] In some embodiments, the tape 50 is formed solely of an optical functional layer 511. Such a tape consists of a layer 511 having a pattern(s) 11 / (air) cavity profile 12 that is completely embedded within the substrate material (no prominent pattern features are established on the outer surface).

[0084] The functional layers 511 and tapes 50 can be implemented in a number of embedded patterns arranged in a stacked configuration. The configuration includes forming a multilayer solution on a single tape by joining two or more layers 511 to each other (see Figure 12, B). Additionally or alternatively, two or more tapes 50 can be applied on top of each other to form a multilayer tape configuration.

[0085] In some cases, the optical functional layer 511 is thus configured to alternate between two or more patterned layers 511A stacked on top of each other and optionally with a flat substrate layer(s) 511B. Flat, planar interfaces between the patterned layers can thus be established by the patterned layer(s) 511A. The topmost patterned layer may thus be provided with a flat substrate(s) 511B to complete the multilayer structure and allow for complete encapsulation of the pattern(s).

[0086] In some configurations, the tape 50 may further comprise a number of additional layers. In such cases, preferably, the substantially flat and planar substrate layer 511A, on which the cavity 52 is formed, is made of a substantially optically transparent material. The functional layer 511B is configured as a contact layer to establish a contact surface with the topmost structure, such as layer 513. Thus, layer 511B may be configured as an adhesive layer or a dry (solid) layer.

[0087] Regions of the substrate material alternating with the cavities 52 form contact regions or contact points between sublayers 511A and 511B, and between the optical functional layer 511 and additional layers 512 and 513. Under certain conditions, the bonding region 53 forms a so-called optical channel through which light is transmitted between the layers (511, 512, and 513). The optical channel is formed when the substrate material 50A is a substantially translucent carrier medium. Thus, the pattern 51 includes a number of embedded cavities having contact points / optical channels 53 in between.

[0088] The functional layer 511 is manufactured by joining two or more layers together, preferably by lamination, so that the overall flat and planar layer 511B is positioned relative to the patterned layer 511A. In some cases, two or more patterned layers may be laminated on top of each other to form a laminate. In the basic layout, opening cavities formed in the flat and planar patterned layer are embedded in the overall flat and planar interface formed between the layers. A flat contact area 53 is formed during lamination (see also Figure 10, the dashed circle shown in 53). A key advantage of the tape 50 is the possibility of utilizing a roll-to-roll method when imprinting the pattern features and laminating all the layers together so that all functional layers are present in a single product.

[0089] In its basic configuration, the tape comprises at least one functional layer 511 formed together with an embedded cavity optical system. To facilitate adhesion, the tape further comprises at least one adhesive layer (see, for example, 512) on one or both sides of the functional layer or the laminate of the functional layer.

[0090] The tape 50 may further include a number of additional functional layers, such as a base layer (shown as 512 in Figure 3) and a top layer (shown as 513 in Figure 3), which are arranged on one or both sides of the optical functional layer 511 (or the laminate of optical functional layers). These layers provide the tape with a number of additional functions.

[0091] For example, the base layer 512 may be configured as an adhesive layer to enable adhesion to the light guide medium below. The adhesive layer 512 may be provided as an optically transparent adhesive (OCA) or a liquid optically transparent adhesive (LOCA). The adhesive layer may also be provided on any surface of the tape, or on both surfaces (top and bottom) of the tape. Thus, the tape 50 can be configured as a double-sided adhesive tape for attaching different elements to either side of the tape.

[0092] The top layer / outer layer 513 is a functional outer layer, which can be an optically transparent layer, an opaque layer, a reflective layer, or a low refractive index (R i It can be composed of any one of the following layers. Alternatively, the top layer 513 can be composed of an adhesive layer similar to the base layer 512.

[0093] In some configurations, the optical incoupling tape is configured to perform collaborative multifunctions, where the directivity and wavelength management of light are performed, for example, by an integrated wavelength conversion layer, and monochromatic light, such as blue LED light, is partially or completely converted.

[0094] Optical incoupling tapes can partially or partially control monochromatic light, such as blue (LED) light. An additional functional layer (512, 513) may be provided, configured as a wavelength conversion layer for complete conversion. The wavelength conversion layer may be located on the upper and / or lower surface of the light guide. In the latter case, the wavelength conversion layer may be located together with the adhesive layer to form an optical connection with the light guide. This additional conversion layer may be utilized on the edge or planar region of the light guide (the light distribution region of the light guide). Alternatively or additionally, the wavelength conversion layer may be utilized together with the incoupling element 150.

[0095] As an example, one of the additional layers (e.g., 512, 513) may be configured as a black layer that absorbs some of the light passing through the optical path 53, forming a contact point at the interface between the layers. The tape having the black layer may be provided, for example, on the back side of the optical element. In another exemplary configuration, the additional layer(s) may be an optically transparent layer that transmits light passing through the contact point 53 at the interface between the layers (511, 512, 513). As described above, the contact point (optical path) is formed by the substrate region 53. Similarly, any of the additional layers may be configured as a reflector layer, and the material of the layer may be employed to produce specular reflection, Lambertian reflection, or any other reflective opaque material. One special solution is to place a low refractive index (R) on the back side of the optical functional layer 511 or inside the layer 511. i This involves utilizing a layer such that the contact point 53 causes internal total internal reflection with respect to light incident thereon. The described solution typically improves the light intensity distribution / optical harmonic efficiency by about 6% to about 20%, depending on the fill factor and shape of the interconnection point (region 53). The described configuration should be adjusted on a case-by-case basis, taking into account the position of the tape on the light guide medium.

[0096] The primary optical function of the tape 50 is to incouple the optical radiation emitted from at least one emitter 30 and to adjust the direction of the optical radiation incident on the pattern(s). The tape is configured to adjust / modify the direction of received light such that the light incident on the pattern(s) 51 is deflected and obtains a propagation path through a series of internal total internal reflections through the light guide medium 20. Thus, the pattern(s) 51 are designed such that the tape(s) mediate incoupled light propagation through the light guide medium (and optionally toward the outcoupling region(s) 21) and optionally control the distribution of light propagating through the light guide 20.

[0097] The light 31 received by the pattern is incoupled and deflected at the interface between each cavity 52 and the substrate material 50A surrounding the cavity. In this way, the pattern 51 and its feature portions (cavities) perform an optical function or set of functions related to incoupling and adjusting the direction of the light received therein. As the incoupled and / or deflected light 32 obtains a propagation path through the light guide medium, the angle of incidence at the interface between each cavity and the substrate material surrounding the cavity becomes greater than or equal to the critical angle of internal total internal reflection.

[0098] The pattern 51 becomes optically functional by assigning a number of parameters to individual cavities or groups of cavities within the pattern, including but not limited to dimensions (size), shape, cross-sectional profile, orientation and position within the pattern, fill factor, and periodicity.

[0099] The fill factor (FF), defined by the percentage (%) ratio of optical features 52 per unit area, is one of the important parameters when designing optical solutions. The fill factor defines the relative proportion of features 52 in a reference area (e.g., one pattern or any other reference area).

[0100] Thus, each cavity within the pattern constitutes a profile having a certain number of optically functional surfaces. For illustrative purposes, optically functional surfaces 521 and 522 (hereinafter referred to as the first and second optically functional surfaces, respectively) are schematically shown in Figure 3 (see also Figure 4). Each of these surfaces is located at the boundary interface between the cavity 52 and the surrounding substrate medium. One of the surfaces mentioned (here, surface 521) may be provided as a substantially horizontal plane substantially parallel to the longitudinal axis / plane of the light guide, and the light source(s) may emit light along substantially the same axis / plane. The other surface (here, surface 522) may be provided as an inclined or perpendicular surface to the first surface. In practice, all surfaces within the cavity may be optically functional.

[0101] The optical functional surface(s) are thus established by any(s) surfaces formed at the interface between each cavity and the material of the substrate surrounding the cavity.

[0102] In some configurations, each of the optical functional surfaces (one or more) in the individual cavities within the pattern is established by one of the following: a low refractive index reflector, polarizer, diffuser, absorber, or any combination thereof. Thus, one of the optical functional surfaces, e.g., 521, 522, is low R i It can be equipped with an appropriate coating, such as a protective coating.

[0103] As described above, one of the main functions of the optical incoupling tape 50 is the incoupling and deflection of light incident on the pattern at an incident angle greater than the critical angle of internal total internal reflection. The optical function performed by the tape is applied to light incident on the pattern (incident at the interface between the cavity and the surrounding medium). The incident light is incoupled and further deflected (direction changed) by a certain angle from its original propagation path by the (air) cavity optics embedded inside the tape.

[0104] In addition to regulating the distribution of light propagation mediated by the TIR through the light guide medium, the tape is configured to perform a number of additional optical functions. Here, a particular function or combination of functions is determined by a number of factors, including the configuration of the cavity profile(s) in the pattern and the selection of materials (e.g., the substrate material forming the optical functional layer 511, the materials for the additional layers 512 and 513, and the cavity filling material), as well as related parameters of the cavity and surrounding materials.

[0105] In the tape 50, at least one pattern is configured to perform an optical function related to incoupling light emitted from at least one emitter 30 and adjusting the direction of light received thereon. Herein, the optical function includes, but is not limited to, reflection, absorption, transmission, collimation, refraction, diffraction, polarization, and any combination thereof.

[0106] The cavities within a pattern perform an optical function (one or more) individually or collectively. Therefore, the pattern may be configured such that all cavities within the pattern perform the same function (collective performance). In such a case, the pattern may consist of the same (identical) cavities. Alternatively, each individual cavity 52 within the same pattern may be designed to establish at least one optical function related to the adjustment of the direction of light received therein. This is done by adjusting cavity-related parameters such as dimensions, shape, cross-sectional profile, orientation, position, periodicity, and fill factor (during the design and manufacturing stages), as described above. The tape 50 can consist of a number of patterns, where each pattern consists of feature parts / cavities that differ from any other pattern(s) within the tape in terms of at least one parameter. It has been done.

[0107] In a tape, the pattern(s) are variably configured by a certain number of cavity-related parameters, where these cavity-related parameters consist of individual parameters or any combination of parameters selected from the group consisting of dimensions, shape, cross-sectional profile, orientation, position, and periodicity.

[0108] The achievement of incoupling and deflection / direction (or direction change) functions is aided by providing optical path regions 53 between the cavities 52 (Figure 3). The configuration of the optical path depends largely on the configuration of the cavities and the arrangement of the cavities in the pattern, but for example, the light transmission characteristics can be controlled and optimized by the selection of the substrate material.

[0109] Incoupling light to which an optical direction-changing function is applied (i.e., incoupling rays whose direction is adjusted through interaction with the cavity pattern), also called deflected and / or directed (or direction-changed) light (32, Figure 3), obtains a propagation path through the light guide medium 20 via a series of internal total internal reflections.

[0110] The patterns (or multiple patterns) 51 in the tape can be further adjusted so that light is incident on the patterns (or multiple patterns) when the angle of incidence at the interface between each cavity in the pattern and the material of the substrate surrounding the cavity is greater than or equal to the critical angle of internal total internal reflection. With this arrangement, the direction of the light received by the tape 50 and the patterns (or multiple patterns) 51 is changed at the interface between each cavity in the pattern and the material of the substrate surrounding the cavity to obtain a propagation path through the light guide medium, so that the angle of incidence at the interface between the light guide medium and its surroundings, and optionally the angle of incidence at the interface between each cavity and the material of the substrate surrounding the cavity, is greater than or equal to the critical angle of internal total internal reflection.

[0111] The incoupling tape 50 further adjusts the direction of the incoupling light so that it reaches the plane of the boundary (interface) between the light guide medium and its surroundings, and optionally, the plane of the boundary (interface) between each cavity and the substrate medium surrounding the cavity, at an incident angle greater than the critical angle of internal total internal reflection.

[0112] For clarity, the term “deflection” is used herein primarily in reference to incoupling rays whose direction is adjusted / changed in tape 50 (i.e., changed to deviate from the original path emitted by the emitter), while the term “direction (or transformation)” applies to both rays that are deflected (direction-changed) in tape and rays that, after being deflected in tape, obtain a propagation path through a series of TIRs via the light guide. Both deflection and direction (or transformation) functions aim to adjust the direction of optical radiation as a result of light interacting with interface / boundary materials (e.g., air-plastic). These interactions occur through a number of optical functionalities, such as reflection and refraction.

[0113] When light reaches the pattern at an incident angle within a certain range, it undergoes total internal reflection in the cavity 52. ​​Therefore, the cavity 52 can be configured to receive and further distribute light that reaches the pattern (at an incident angle greater than or equal to a critical angle with respect to the interface formed by any one of the optical functional surfaces) from the viewpoint of the functional surfaces 521 and 522.

[0114] When a light ray travels through an optically transparent substrate 50A and strikes one of the internal cavity surfaces (521, 522) at a certain angle, the ray is either reflected from that surface to the substrate or refracted into the cavity at the cavity-substrate interface. The conditions under which a light ray is reflected or refracted are determined by Snell's law, which describes the relationship between the angle of incidence and the angle of refraction of a light ray incident at the interface of two media with different refractive indices. Depending on the wavelength of the light, at a sufficiently large angle of incidence (exceeding the "critical angle"), no refraction occurs, and the light energy is confined within the substrate.

[0115] The critical angle is the angle at which the phenomenon of total internal reflection occurs, relative to the surface normal. When the angle of refraction is 90 degrees relative to the surface normal, the angle of incidence becomes the critical angle (i.e., equal to the critical angle). Typically, a higher refractive index (R) i ) from a medium with a lower refractive index (R i When light passes through a medium, for example, plastic (R i1.4 to 1.6) and glass (R i 1.5) to air (R i 1) or other media with a slightly lower refractive index, total internal reflection (TIR) occurs when light passes through. From a high R i medium to a low R i For a light ray traveling from a medium to a low R medium, when the incident angle (e.g., at a glass-air interface) is greater than the critical angle, the medium boundary functions as a very good mirror, and the light is reflected (back to a high R medium such as glass). When TIR occurs, energy transfer through the boundary does not take place. On the other hand, light incident at an angle (plural possible) less than the critical angle is partially refracted and partially reflected from the high R i medium. The ratio of the reflected light to the refracted light depends greatly on the incident angle and the refractive index of the medium. i The critical angle varies depending on the substrate-air interface (e.g., plastic-air, glass-air, etc.). For example, in most plastics and glasses, the critical angle constitutes approximately 42 degrees. Thus, in an exemplary waveguide, light incident at a 45-degree angle (with respect to the surface normal) on the boundary between a light-transmissive medium such as a PMMA sheet and air will probably be reflected back into the light guide medium, thereby not causing light outcoupling.

[0116] The same principle also applies to light traveling within a light guide medium via a series of TIR. Note that light propagation by TIR through a light guide can also occur outside the boundaries defined by the incoupling tape(s). The TIR phenomenon is established by the light guide design and the choice of the light guide medium.

[0117] Two-dimensional or three-dimensional patterns are typically established to have a regular periodic pattern feature or a variable periodic pattern feature. Periodicity is a feature necessary to control and deflect plane waves in the light guide medium and to convert the direction of incident light (i.e., light incident on the pattern) for a preferred distribution. Additionally, aperiodic pattern features can be utilized to harmonize non-uniform light beams and / or light distribution.

[0118] ​

[0119] In each individual pattern, the cavity 52 can be established by discrete or at least partially continuous pattern features. Examples of discrete patterns include dots and pixels.

[0120] Figure 4 shows embedded cavity patterns 51 (A, B, C) with different fill factors. For example, Figure 4 (configuration A) shows that the cavity feature portion 52 can be characterized by a number of parameters such as the length (l), width (w), and height (h) of the feature portion (bottom width w in Figure 4). b (This shows). Additionally, feature portion 52 can be characterized by the length of the period (p) and the tilt angle (θ).

[0121] Configurations A, B, and C shown in Figure 4 differ from each other only in terms of fill factor. Feature section 52 indicates a cavity, preferably an air cavity (the material 50A surrounding the cavity 52 is not shown). Optical functional surfaces 521 and 522 are shown with respect to pattern 51(A). The comparison results are summarized in Tables 1-3 below.

[0122] Table 1. Pattern 51(A), Figure 4. Pattern fill factor 100% (gap 0). Optimized conical tilt, optimized blazed angle. The abbreviation LGP stands for "light guide plate". The tilt angle and blazed angle (also called blaze angle) are shown in Figure 4.

[0123] [Table 1]

[0124] Table 2. Pattern 51(B), Figure 4. Pattern fill factor 92% (gap 5 μm / micrometer). Optimized cone tilt, optimized blazed angle.

[0125] [Table 2]

[0126] Table 3. Pattern 51(C), Figure 4. Pattern fill factor 86% (gap 10 μm / micrometer). Optimized cone tilt, optimized blazed angle.

[0127] [Table 3]

[0128] Patterns A, B, and C are provided on the incoupling tape 50 attached to the back side of the light guide (Figure 4). An emitter device 30 (with collimator) is installed on the opposite side (front side) of the light guide. Therefore, this arrangement is the same as schematically shown in Figure 1B. The dashed-line frame (Figure 4) shows a light cone (collimated and tilted light) with a fixed conical edge of 0.2 degrees (°).

[0129] Figure 5 is a graph showing the incoolation light intensity (%), y-axis, with respect to the light source collimation (degrees, light cone; x-axis), and the positions (shown in Figure 4) of patterns 51 (A, B, C) having different fill factors. The tape 50 with the aforementioned patterns 51 (A, B, C) is positioned on the back side of the light guide (opposite side from the light source 30), as shown in Figure 4.

[0130] Figure 6 illustrates a similar arrangement to that shown in Figure 4, but with a low refractive index (low R) in the embedding pattern. i It has a cavity feature section 52 made of ) material. i The material may be provided as a cavity filler and / or as a coating material for coating the cavity. The pattern fill factor is 100%.

[0131] Low refractive index materials are typically materials with a refractive index in the range of 1.10 to 1.41. iThe refractive index of the material is typically less than 1.5, preferably less than 1.4. The refractive index of the material mentioned in Figure 6 is 1.18 (in this case, low R i The material is the material that fills cavity 52. ​​In such cases, the filling pattern will have an optical filtering function (defined as the ability to change the spectral intensity distribution or polarization state of electromagnetic radiation incident on it). The filter can be involved in performing various optical functions such as transmission, reflection, absorption, refraction, interference, diffraction, scattering, and polarization.

[0132] Figure 7 shows the light source collimation (degrees, light cone; x-axis) and low R, as explained with reference to Figure 6. i Incoupling of the position of a pattern having a cavity containing material This is a graph showing light intensity (%), y-axis.

[0133] Figure 8 illustrates the arrangement schematically shown in Figure 1A. The incoupling tape 50 is provided on the surface side of the light guide 20, and light (from the emitter 30) is incident directly on the tape. The embedded cavity pattern 51 is composed of multiple prism cavity features 52 (the material 50A surrounding the cavities 52 is not shown). Configurations A, B, and C shown in Figure 8 differ from each other only in terms of fill factor. The emitted light is collimated by a collimator (lens). The comparison results are summarized in Tables 4-6 below.

[0134] Table 4. Pattern 51(A), Figure 8. Pattern fill factor 100% (gap 0). Optimized conical tilt, optimized blazed angle. The abbreviation LGP stands for "light guide plate". Prism angle 1 refers to the prism angle on the left side, and prism angle 2 refers to the prism angle on the right side (Figure 8).

[0135] [Table 4]

[0136] Table 5. Pattern 51(B), Figure 8. Pattern fill factor 92% (gap 5 μm / micrometer). Optimized cone tilt, optimized blazed angle.

[0137] [Table 5]

[0138] Table 6. Pattern 51(C), Figure 8. Pattern fill factor 86% (gap 10 μm / micrometer). Optimized cone tilt, optimized blazed angle.

[0139] [Table 6]

[0140] Figure 9 shows the incoolation light intensity (%) with respect to light source collimation (degrees, light cone; x-axis). This graph shows the y-axis and the positions of patterns 51 (A, B, C) having different fill factors (as shown in Figure 8). The tape 50 with the aforementioned patterns 51 (A, B, C) is placed on the surface side of the light guide (the same side as the light source 30), as shown in Figure 8.

[0141] Figure 10 is a cross-sectional view of an optical incoupling tape 50 with an embedded air cavity pattern 51. This tape is attached to the upper surface of a light guide element 20 (light guide plate, LGP). Collimated light from the emitter 30 is received directly by the tape 50. The enlarged area shown in Figure 10 represents the tape 50 having the embedded pattern 51 (formed by layers 511A and 511B as described above) and an underlayer (512) of optically transparent adhesive. The cavity 52 is filled with air. A contact area 52 is formed to allow light to pass through the layer. The fill factor is 86%.

[0142] The setup shown in Figure 10 allows for an incoupling efficiency of 73–75% with a 50° tilt angle and a collimation cone of approximately 10° (with Fresnel reflection).

[0143] The setup can be further modified by providing at least one layer 515 inside the tape 50 and the optical functional layer 511. The internal layer(s) 515 can be configured, for example, as an anti-reflective (AR) layer. In this example (Figure 10, right), the flat substrate layer 511B is pre-coated with an AR coating (515) before being bonded to the patterned layer 511A. Similarly, the patterned layer 511A can be pre-coated with a coating 515. Setups including internal AR coatings enable the achievement of incoupling efficiencies of up to approximately 83%.

[0144] Figures 11A and 11B show the state in which an optical incoupling tape 50 is provided on the upper surface of a light guide element 20 equipped with a collimated light source 30.

[0145] Figure 11A is a cross-sectional view of a tape 50 having a fully embedded air cavity pattern with an optimized prism cavity feature 52. Other setup parameters are as follows: LED collimation (light cone) approximately 10°, LED light tilt 50°, no Fresnel reflection, and the intensity distribution inside the light guide element is discretized, which is typically observable in the cross-section of the light guide. This tape can achieve an incoupling efficiency of up to 87%.

[0146] Figure 11B is a cross-sectional view of an exemplary tape 50 having an air cavity pattern with an optimized prism cavity feature. Other setup parameters are the same as in Figure 11A. This tape enables achieving an incoupling efficiency of up to 94%.

[0147] Within the pattern, cavities can be further configured and arranged to form substantially variable (or segmented) periodic patterns, and each local pattern design has features that are substantially variable within its pattern. Thus, in some configurations, the tape 50 comprises a number of patterns arranged as periodic segments, each segment having a predetermined area and period length (not shown). These local patterns can be made variable by changing pattern and / or cavity-related parameters to control the light incident thereon at a given angle or range of angles. The cavity profile can be configured variably in terms of a number of parameters selected from any one of the following: dimensions, shape, cross-sectional profile, orientation, and position within the pattern.

[0148] In the tape, the cavity 52 is thus established by a two-dimensional or three-dimensional pattern feature having a cross-sectional profile selected from the group consisting of linear, rectangular, triangular, blazed, inclined, trapezoidal, curved, wavy, and sinusoidal profiles.

[0149] Furthermore, with respect to the configuration and arrangement of the pattern(s), the tape 50 is designed and optimized for specific light guide thicknesses and other light guide-specific parameters.

[0150] An example of a three-dimensional diamond blaze pattern design 51 having an air cavity 52 is shown in Figure 12 (frame in the upper left corner). This pattern may be configured as a hybrid optical pattern. Figure 12 further shows several embodiments relating to a tape 50 and providing it to a light guide element 20. Thus, configuration A shows a tape 50 having a single pattern layer.

[0151] Configuration B shows a tape implemented as a two-layer or multilayer solution. In Configuration B, the functional layer 511 and the tape 50 can be implemented in a number of embedded patterns arranged in a stacked configuration. The configuration involves forming a multilayer solution in a single tape by bonding two or more patterned layers (511A), optionally optical functional layers (511), to each other. In some configurations, the patterned layers 511A may optionally alternate with a flat substrate layer 511B. Additionally or alternatively, two or more tapes 50 (50-1, 50-2) can be applied on top of each other to appropriately form a two-layer or multilayer tape configuration (in a manner similar to Configuration (ii), Figure 2).

[0152] In a multilayer configuration, the tape may be formed using a laminate comprising two or more patterned layers (referred to as 511A) arranged on top of each other. The flat, planar interfaces between the layers may therefore be established by the patterned layer 511A alone (requiring that the layer establishes a pattern on one of its surfaces, while the other surfaces remain flat overall). The topmost patterned layer may therefore be provided with a flat substrate 511B to complete the multilayer structure and allow for complete encapsulation of the pattern(s).

[0153] Therefore, the laminate may be implemented using any one of the following: an entirely flat substrate layer (511B) and alternating patterned layers (multiple) (511A), an optically functional layer (511), and a tape 50. Patterns located at different levels within the laminate may be configured to perform the same or different optical functions related to incoupling and adjustment of the direction of light received thereon, the optical functions being selected from the group consisting of incoupling, reflection, direction change, deflection, absorption, transmission, collimation, refraction, diffraction, diffusion, polarization, and any combination thereof.

[0154] In configuration C, the tape 50 is provided with a shaping structure 54 at at least one of its ends. Similar arrangements of shaping structures at both ends of the tape can be conceived (not shown). The shaping structure is defined by at least a portion of the outer surface of the tape substantially opposite the light guide mounting surface. The configuration of the shaping structure may be tapered, inclined (sloping), or convex with respect to the longitudinal plane of the planar light guide. The tape 50 having the optical wedge 54 formed thereon may be configured for hybrid coupling (in terms of optical pattern).

[0155] Tape 50 is manufactured using a roll-to-roll lamination process. It can also be provided in roll form.

[0156] In one aspect, an optical device (unit) 150 is provided. The unit includes a tape 50 and at least one emitter 30 for emitting optical radiation incident on the tape 50 (as described with reference to Figure 1C). Thus, the unit 150 provides a compact solution in which the light source(s) is integrated with the optical system. The latter can be configured as an embedded (air) cavity optical system or a relief (open cavity) optical system.

[0157] Figures 13A and 13B illustrate the use of a combination of an optical incoupling tape 50 and a unit 150 utilizing it with an optical harmonic tape 10. The harmonic tape 10 (also called a deflection tape) may be mounted on the light guide in a predetermined area following the incoupling area (the latter on which the incoupling tape 50 or unit 150 is attached / mounted). The harmonic tape may thus cover one or more areas within the light distribution area of ​​the light guide, i.e., the area between the incoupling area and the outcoupling area. The tape 10 may be arranged along the entire light distribution area of ​​the light guide.

[0158] The harmonic tape 10 is implemented based on a cavity optical system solution similar to that described herein with respect to the optical incoupling tape 50. The primary function of the incoupling tape 50 is to mediate light propagation through the light guide by adjusting the incoupling of the outgoing light rays and the direction of the incoupled light. The primary function of the harmonic tape 10 is to control the distribution of light propagating through the light guide by deflecting and redirecting the light incident on the tape. The optical functions of tapes 50 and 10 are adjustable in terms of cavity-related parameters and tape-related parameters (e.g., substrate material, overall implementation, etc.), as described herein. Therefore, providing the harmonic tape 10 makes it possible to improve the uniformity of the internal light distribution in the light guide (mediated by the enhanced TIR function enabled by the harmonic tape 10).

[0159] In another aspect, a method for manufacturing an optical incoupling tape 50 is provided. The method includes manufacturing a patterning master tool for at least one pattern by a suitable manufacturing method; transferring the pattern onto a substrate to produce a patterned substrate; and applying additional flat and planar substrate layers onto the patterned substrate to produce one or more embedded cavity patterns, such that internal cavities are formed at the perfectly flat and planar interfaces between the substrate layers.

[0160] The patterns can be fabricated by any suitable method, including but not limited to lithography, 3D printing, micromachining, laser engraving, or any combination thereof. Other suitable methods may also be utilized.

[0161] The embedded cavity pattern(s) is preferably carried out by a roll-to-roll lamination method, and the sublayers 511A and 511B are laminated to each other to form the optical functional layer 111.

[0162] An additional substrate layer (511B) can be applied on the patterned substrate layer (511A) by a lamination method selected from roll-to-roll lamination, roll-to-sheet lamination, or sheet-to-sheet lamination.

[0163] Once a pattern is created, it is advantageous to further duplicate it by any suitable method such as imprinting, extrusion, or 3D printing. It may be used.

[0164] A typical production line is employed to carry out the following processes: a) pattern creation and duplication, b) cavity lamination, c) preparation and lamination of other / additional layers, and d) cutting of the final film. This production line can also be employed for the manufacture of narrow or wide tape products.

[0165] The sheets or rolls of optical incoupling tape manufactured in steps a to c can be transported to another location for cutting.

[0166] The present invention further relates to a light guide 20 comprising an optically transparent medium configured to establish a path for light propagation through the light guide, and an optical incoupling tape 50 configured according to the embodiments described herein, wherein the optical incoupling tape is attached to at least one plane of the light guide. In some configurations, the optical incoupling tape is attached to the light guide by adhesive.

[0167] Further uses of the light guide in lighting and / or display are provided. The light guide can be used for lighting and display-related purposes, including but not limited to decorative lighting, light shields, masks, windows, facades and ceiling lighting, public and general lighting, signage, billboards, posters and / or advertising board lighting and displays, and solar applications. It will be apparent to those skilled in the art that the basic idea of ​​the present invention is intended to cover various modifications thereto as the art progresses. Accordingly, the present invention and its embodiments are not limited to the examples described above, but rather can be broadly modified within the scope of the appended claims.

[0168] References 1.Carlos Angulo Barrios and Victor Canalejas-Tejero, "Light coupling in a Scotch tape waveguide via an integrated metal diffraction grating," Opt. Lett. 41, 301-304 (2016). 2.Bernard C. Kress, “Optical waveguide combiners for AR headsets: features and limitations", Proc. SPIE 11062, Digital Optical Technologies 2019, 110620J (16 July 2019. 3.Moon et al., “Microstructured void gratings for outcoupling deep-trap guided modes," Opt. Express 26, A450-A461 (2018).

Claims

1. An optical incoupling tape for a light guide, arranged such that light emitted from an emitter device is incident on a light guide medium before light emitted from the emitter device is incident on the light guide medium, Substrate and A pattern formed by a plurality of periodic pattern feature portions embedded in the material of the substrate and configured as optical functional cavities, wherein the optical functional cavities are filled with a material having a refractive index different from that of the material of the substrate surrounding the optical functional cavities, and Equipped with, The at least one pattern is configured to incouple the incident light and generate incoupled light, and to adjust the direction of the incoupled light, thereby causing the incoupled light to obtain a propagation path through the light guide medium via a series of internal total internal reflections. The optical incoupling tape is attachable to at least one plane of the light guide medium, thereby forming an optical contact for light transmission between the incoupling tape and the light guide medium.

2. The optical incoupling tape according to claim 1, wherein the incoupling light is redirected at the interface between each of the optical functional cavities and the material of the substrate surrounding the optical functional cavities to obtain the propagation path through the light guide medium, and thereby the angle of incidence at the interface between the light guide medium and the surroundings, and optionally the angle of incidence at the interface between each of the optical functional cavities and the material of the substrate surrounding the optical functional cavities, is greater than or equal to the critical angle of internal total internal reflection.

3. The optical incoupling tape according to claim 1 or 2, wherein the at least one pattern is configured to perform an optical function related to adjusting the incoupling and direction of received light, the optical function being selected from the group consisting of reflection, absorption, transmission, collimation, refraction, diffraction, polarization, and any combination thereof.

4. The optical incoupling tape according to any one of claims 1 to 3, wherein the at least one pattern is made optically functional by providing a cavity or group of cavities within the at least one pattern with a certain number of parameters, the certain number of parameters consisting of any combination of parameters selected from the group consisting of dimensions, shape, cross-sectional profile, orientation, periodicity, and fill factor.

5. The optical incoupling tape according to any one of claims 1 to 4, wherein each individual optical functional cavity within the at least one pattern has a number of optical functional surfaces.

6. The optical incoupling tape according to claim 5, referencing claim 2, wherein the optical functional surface(s)

7. The optical incoupling tape according to any one of claims 1 to 6, wherein each individual optical functional cavity within the at least one pattern has an optical functional surface (one or more) established with one of a low refractive index reflector, polarizer, diffuser, absorber, or any combination thereof.

8. The optical incoupling tape according to any one of claims 1 to 7, wherein the optical functional cavity is configured and arranged within the at least one pattern so as to form a plurality of periodic patterns having different periods.

9. The optical incoupling tape according to any one of claims 1 to 7, wherein the optical functional cavity is configured and arranged within the at least one pattern to form a constant periodic pattern.

10. The optical incoupling tape according to any one of claims 1 to 9, wherein in at least one pattern, the optical functional cavity is established by discrete or at least partially continuous pattern feature portions.

11. An optical incoupling tape according to any one of claims 1 to 10, comprising a certain number of patterns arranged as periodic segments.

12. The optical incoupling tape according to any one of claims 1 to 11, wherein the at least one pattern is composed of a plurality of different cavity-related parameters, the plurality of different cavity-related parameters being composed of individual parameters or any combination of parameters selected from the group consisting of dimensions, shape, cross-sectional profile, orientation, position, periodicity, and fill factor.

13. The optical incoupling tape according to any one of claims 1 to 12, wherein the optical functional cavity is established by a two-dimensional or three-dimensional pattern feature portion having a cross-sectional profile selected from the group consisting of linear, rectangular, triangular, blazed, inclined, trapezoidal, curved, wavy, and sinusoidal profiles.

14. The optical incoupling tape according to any one of claims 1 to 13, wherein the optical functional cavity is filled with a gaseous material.

15. An optical incoupling tape according to any one of claims 1 to 14, configured to be affixed to one or more planes of the light guide by adhesive.

16. The optical incoupling tape according to any one of claims 1 to 15, wherein the at least one pattern comprises an optical functional cavity formed in the substrate provided as a flat, planar substrate layer.

17. The optical incoupling tape according to claim 16, wherein the flat, planar substrate layer on which the optical functional cavity is formed is made of an optically transparent material.

18. The optical incoupling tape according to any one of claims 1 to 17, wherein the at least one pattern includes an optical functional cavity formed at the interface with an additional flat, planar substrate layer provided as an optically transparent layer, a reflective layer, and / or a colored layer.

19. The optical incoupling tape according to any one of claims 1 to 18, wherein the optical functional cavity is composed of a certain number of embedded patterns arranged in a stacked configuration.

20. An optical incoupling tape according to any one of claims 1 to 19, comprising a wedge structure.

21. The optical incoupling tape according to any one of claims 1 to 20, further comprising a wavelength conversion layer.

22. An optical incoupling tape, which is arranged so that light emitted from an emitter device is incident on a light guide medium before the light emitted from the emitter device is incident on the light guide medium, and a method for manufacturing an optical incoupling tape comprising at least one pattern formed by a plurality of periodic cavity features embedded in a substrate material, To manufacture a patterned master tool for at least one pattern by a manufacturing method selected from lithography, 3D printing, micromachining, laser engraving, or any combination thereof, Transferring the pattern onto the substrate to produce a patterned substrate, Applying an additional substrate layer or cover layer to the patterned substrate to generate a cavity pattern (one or more) Includes, The at least one pattern includes an optical functional cavity configured as an optical functional cavity filled with a material having a refractive index different from that of the substrate material surrounding the optical functional cavity, The at least one pattern is configured to incouple the incident light, generate incoupled light, and adjust the direction of the incoupled light so that the incoupled light obtains a propagation path through the light guide medium via a series of internal total internal reflections. method.

23. The method according to claim 22, wherein the additional substrate layer is applied to the patterned substrate layer by a lamination method selected from roll-to-roll lamination, roll-to-sheet lamination, or sheet-to-sheet lamination.

24. The method according to claim 22 or 23, comprising a reproduction of the fabricated pattern, wherein the pattern reproduction method is selected from imprint, extrusion reproduction or 3D printing.

25. A light guide comprising an optically transparent medium configured to establish a path for light propagation through the light guide medium, and an optical incoupling tape according to any one of claims 1 to 21, wherein the optical incoupling tape is attached to at least one plane of the light guide medium.

26. The light guide according to claim 25, wherein the optical incoupling tape is attached thereon by adhesive.

27. Use of the light guide according to claim 25 or 26 in illumination and / or display.

28. A roll of optical incoupling tape, wherein the optical incoupling tape is configured according to the definition of any one of claims 1 to 21.

29. An optical unit comprising an optical incoupling tape having an adhesive layer for attaching a light guide, and at least one emitter device, wherein the optical incoupling tape is configured according to the definition of any one of claims 1 to 21.

30. The optical unit according to claim 29, wherein the at least one emitter device is selected from the group consisting of light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), laser diodes, LED bars, OLED strips, microchip LED strips, and cold cathode tubes.

31. An optical unit according to either claim 29 or 30, which incorporates claim 21, comprising at least one optical emitter device configured to emit monochromatic light, and the optical incoupling tape including the wavelength conversion layer.

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