Thermomechanical deformation of polymer bodies into curved optical windows

Abstract

A system (2000) for producing a curved optical window (400) from an (elongate) polymeric body (1400), wherein the system (2000) comprises a set of first roller elements (410), an actuator system (500), a heating system (700), and a control system (1500); wherein the first roller element (410) has an axis of rotation (A1), wherein the first roller element (410) is configured to be tiltable, wherein the axis of rotation (A1) has a controllable mutual angle (alpha1); wherein the actuator system (500) is configured to control (i) a mutual angle ([alpha] 1) and (ii) a rotational speed of at least one of the first roller elements (410); wherein the heating system (700) is configured to heat the (elongate) polymeric body (1400); wherein the control system (1500) is configured to control the actuator system (500) and the heating system (700) such that at least a portion of the (elongated) polymeric body (1400) is heated (with the heating system (700)) while being conveyed between the first roller elements (410) and bent (by controlling the mutual angle (alpha1) and the rotational speed) into a curved optical window (400).

Description

Technical Field

[0001] The invention relates to a system for producing a curved optical window from a (slender) polymer body. The invention also relates to a method for producing a curved optical window from a (slender) polymer body (using such a system). The invention also relates to a curved optical window (such as, for example, produced using such a system or according to such a method). The invention also relates to a system for generating light. The invention also relates to a lighting device comprising such a light generating system. Background Art

[0002] Lighting systems are known in the art. For example, US10253944B1 describes an example of a lighting fixture that includes a housing, a light source in the housing, and a diffuser. The diffuser is supported by the housing at a distance from the light source so as to receive light from the light source and diffuse the light for lighting. The diffuser has a three-dimensional compound curvature and a perimeter having at least two edges connected at a vertex. Each such edge is a two-dimensional plane curve. The at least two edges are not coplanar with each other. In some examples, the back panel of the housing may have a similar three-dimensional compound curvature and perimeter. Summary of the invention

[0003] A light generating device or system may provide light via an optical window by means of transmission. The optical window may in particular be formed of a transparent (or translucent) material through which the light may escape, or alternatively, the optical window may (even) be a diffuser. A diffuser (or "light diffuser") is a device that may diffuse light, such as by means of scattering. In particular, the scattering of light may destroy the alignment properties of the light waves, result in pseudo-random variations in the phase of the light, and thus provide diffuse light. A light beam may be desired in a workplace such as an office, a school, a home, etc. However, diffuse light may (also) be desired due to the soothing (i.e. less glaring) light quality compared to exposure to a light beam. Therefore, for this purpose, the lighting system may be configured with an optical window through which the light may escape, which optical window may be transparent or translucent.

[0004] Modern lighting devices can be configured in irregular shapes. The motivation behind the shape of the lighting device can depend on the application of the lighting device. For example, in a location such as a school or workplace, the lighting device can have an elongated shape that can be arranged around furniture or specific locations on walls and ceilings. Such a configuration can have practical advantages in directing the location where the light source (in the lighting device) is located. In addition, such a light source can (also) provide the advantage of being selective in the location where the light is provided, such as providing more lighting on the table and providing less lighting (and diffuse lighting) at the walls of the room (in which the lighting device is placed). Therefore, in order to provide lighting with such a lighting device, an optical window of a complementary geometry can be used. Such an optical window can further contribute to the function of the lighting device by controlling the degree to which the light provided is diffused. For example, a light diffuser can provide more diffuse light to illuminate walls and corridors compared to a table or workplace (where the light beam can be coupled out). In addition, it can also be advantageous to use a curved optical window, which can be arranged around columns or furniture in a workplace, school, office, etc.

[0005] However, producing such optical windows (especially curved optical windows) can be challenging. Basically, an optical window of the desired shape can be cut from a large sheet of polymer material in the desired shape. This causes a number of disadvantages, the main of which can be that the remaining portion of the sheet of polymer material (from which the optical window is cut) can be wasted. Special polymer materials may be required for specific optical windows. Manufacturing such polymer materials can be expensive, and therefore, it is desirable to minimize the waste of such materials. Waste can be minimized by, for example, smart cutting or special tools, where multiple designs can be cut from the same polymer material. However, this may not be possible in all cases, and in addition, designing a system to generate such templates for cutting different optical window designs can be cumbersome.

[0006] An alternative production method may be to use injection molding. A mold (or moulds) may be created, and these may be used to produce an optical window of the desired shape. However, this method (also) suffers from the drawback of requiring a special setup / tool ​​for injection molding. In addition, creating such a mold may be expensive. Each mold or mould may (only) be suitable for a specific shape (or design), and completely new molds may have to be created to produce different windows. Therefore, this may (only) be commercially viable when mass-producing such optical windows.

[0007] Therefore, one aspect of the present invention is to provide an alternative system for producing curved optical windows from (elongated) polymer bodies, which preferably further at least partially eliminates one or more of the above-mentioned disadvantages. The object of the present invention may be to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0008] According to a first aspect, the present invention provides a system for producing a curved optical window from a (slender) polymer body. In particular, the system may include a set of first roller elements (or "roller elements"), an actuator system and a control system. Optionally, the system may include a heating system. In an embodiment, the first roller element may have a rotation axis (A1) (in this article, the first roller element may be configured to be tiltable). In particular, the rotation axis (A1) may have a controllable mutual angle (α1). In an embodiment, the actuator system may be configured to control (i) the mutual angle (α1) and (ii) the rotation speed of at least one of the first roller elements. In an embodiment, the optional heating system may be configured to heat the (slender) polymer body. In particular, the control system may be configured to control the actuator system so that at least a portion of the (slender) polymer body is bent into a curved optical window while being conveyed between the first roller elements (in particular by controlling the mutual angle (α1) and the rotation speed). More particularly, the control system can be configured to control the actuator system and the heating system so that at least a portion of the (elongated) polymer body is heated (using the heating system) and bent (particularly by controlling the mutual angle (α1) and the rotation speed) into a curved optical window while being conveyed between the first roller elements. Thus, in a specific embodiment, the present invention may provide a system for producing a curved optical window from a (slender) polymer body, wherein the system comprises a set of first roller elements, an actuator system, a heating system and a control system; wherein the first roller elements have a rotation axis (A1) (wherein the first roller elements are configured to be tiltable), wherein the rotation axis (A1) has a controllable mutual angle (α1); wherein the actuator system is configured to control (i) the mutual angle (α1) and (ii) the rotation speed of at least one of the first roller elements; wherein the heating system may be configured to heat the (slender) polymer body; wherein the control system is configured to control the actuator system and the heating system such that at least a portion of the (slender) polymer body is heated (using the heating system) and (particularly by controlling the mutual angle (α1) and the rotation speed) is bent into a curved optical window while being conveyed between the first roller elements. Thus, in an embodiment, the present invention may provide a system for mechanically deforming (particularly thermomechanically deforming) a polymer body into a curved optical window.

[0009] Compared to cutting a curved optical window from a sheet of polymer material, with such a system the amount of polymer material required to produce the curved optical window is significantly reduced. Since the curved optical window is produced by conveying the (elongated) polymer body through the first roller element, almost the entire volume (or in particular the entire volume) of the (elongated) polymer body is used and thus the waste of polymer material is limited to a minimum. Furthermore, the limited waste of polymer material reduces the cost of producing such a curved optical window.

[0010] In addition, in the above system, no special tools may be required. No special tools for generating suitable templates for cutting curved optical windows or for injection molding are required. This can further reduce the cost of manufacturing curved optical windows.

[0011] Furthermore, an advantage of using such a system may be that the shape of the curved optical window is configurable. For example, the curvature of the curved optical window and the thickness of the curved optical window may be varied by controlling the rotation speed of one or more first roller elements, controlling the mutual angle (α1) and the degree of heating provided. This may be economically superior to generating a new mold (such as in the case of injection molding).

[0012] And further, in addition to ease of manufacture and low manufacturing costs, the configurability of the geometric configuration of the curved optical windows provides the benefit of making customized curved optical windows. This is particularly advantageous because the curved optical windows can be used in unique lighting systems that are unique to the location where they are used (such as in a specific building). Thus, unique curved optical windows can be produced without requiring large batch production or requiring large inventory space to accommodate the manufactured optical windows.

[0013] As mentioned before, in an embodiment, the present invention may provide a system for producing a curved optical window from a (slender) polymer body. The curved optical window may be produced from a variety of different polymer source materials. Here, the polymer source material refers to a polymer material from which a curved optical window may be produced. Furthermore, the polymer material may refer to the material of the (slender) polymer body and the curved optical window. Thus, in particular, the system may produce a curved optical window from an elongated polymer body, where "slender" may refer to a polymer body that may be substantially configured to be straight (or configured to have a straight axis). Furthermore, in an embodiment, the polymer body may be wound, such as into a bobbin. In particular, the curved optical window may be produced from another curved optical window (such as having a different curvature and / or thickness). And further, in an embodiment, the curved optical window may (also) be produced from a solid block of polymer material. The composition of the polymer material is discussed further below.

[0014] In an embodiment, the first roller element may have an axis of rotation (A1). A roller element here refers to an element that can rotate around an axis, i.e. the axis of rotation (A1). In an embodiment, the system may include a plurality of different first rollers, such as, for example, two first roller elements. However, in particular, more roller elements may (also) be configured. In an embodiment, the first roller element may have a cylindrical geometry, wherein the axis of the cylinder is aligned with the axis of rotation (A1). However, in an embodiment, other configurations such as a conical roller element may also be possible, wherein the radius of the conical element may vary along the axis of rotation (A1). Note that even in embodiments comprising first roller elements of a non-cylindrical shape, the mutual angle (α1) is controllable.

[0015] Hence, the term "first roller element" may particularly refer to two (or more) rollers having rotation axes having a controllable mutual angle (α1 ).

[0016] The term "first roller element" may also refer to one or more sets of two roller elements, wherein the rotation axes of the two roller elements of each set have a controllable mutual angle (α1). In an embodiment, the mutual angles of different sets may be controlled individually.

[0017] In embodiments, these rollers may be used to achieve a specific pattern or shape of a curved optical window. Furthermore, in embodiments, the first roller element may have a wedge shape, or a barrel shape, or other curved profile shape. In particular, in embodiments, the first roller elements may be selected individually, i.e. a "first" first roller element may have a different shape than a "further" first roller element. And further, the roller element may (also) be multifaceted, i.e. the roller element may have a polygonal cross-section, such as a cylinder having at least 5 faces, such as at least 10 faces, such as at least 50 faces. However, in particular, in embodiments, the roller element is cylindrical.

[0018] The roller elements may have a substantially flat surface. However, on one or more of the roller elements, a surface texture may be available. Thus, various surface textures of the curved optical window may be achieved by using one or more of the aforementioned roller elements. For example, the surface texture (or pattern) may be in the form of a sinusoidal profile, a pyramidal pattern, etc. In addition to the first roller element, "additional" roller elements may be configured. Note that in an embodiment, the geometry of one or more first roller elements may be different. Furthermore, the geometry of one or more "additional" roller elements may (also) be different. Additional roller elements may help shape the curved optical window into a desired shape or configuration.

[0019] In particular, in an embodiment, the radius of curvature of the curved optical window can be controlled depending on the rotation speed (and / or torque) of one or more first roller elements, more particularly at least by the mutual angle of the rotation axes of the first roller elements.

[0020] In an embodiment, the first roller element may be configured to be tiltable. In an embodiment, there may be two first roller elements, which may be oriented along their rotation axes (A1). Therefore, the two rotation axes (A1) and therefore the two first roller elements may be configured to be angled relative to each other. Furthermore, in an embodiment, the angle between the two first roller elements may be controllable, i.e. they may vary. Therefore, in particular, the rotation axes (A1) may have a controllable mutual angle (α1). The (elongated) polymer body may be conveyed between two first roller elements configured at a mutual angle (α1), thereby bending the (elongated) polymer body into a curved optical window. Therefore, the curvature of the curved optical window may be controlled, in particular, according to the controllable mutual angle (α1). Furthermore, the cross-section of the curved optical window may (also) be modified due to conveyance between the two first roller elements. Further information on the geometric properties of the curved optical window is discussed further below. In particular, the (elongated) polymer body may be deformed by the first roller elements.

[0021] In an embodiment, the system may include one or more actuators. In an embodiment, these actuators may perform multiple actions. In particular, the actuator may be functionally coupled to the first roller element. Here, "functionally coupled" refers to a mechanical connection, in which the rotational speed and torque from the actuator are transmitted to one or more first roller elements. Thus, in an embodiment, the actuator may rotate the first roller elements at a controllable angular velocity. Furthermore, in an embodiment, the actuator may control the mutual angle (α1) between the first roller elements. And furthermore, the torque applied to the first roller element may (also) be particularly controllable.

[0022] In an embodiment, each of the first roller elements may be functionally coupled to a unique actuator. Alternatively, in an embodiment, a "first" first roller element may be functionally coupled to a "second" first roller element, and the "second" first roller element may (also) be controllable by mechanical coupling to a single actuator. Here, "mechanical coupling" may refer to a connection such as via a set of gears or belts. Thus, mechanical energy from a single actuator may be transferred to one or more of the first roller elements.

[0023] Furthermore, in an embodiment, the first roller element may in particular be configured such that there is no slip between the surface of the first roller element and the surface of the (elongated) polymer body (or polymer material). Here, "no slip" refers to zero relative velocity at any contact point between the first roller element and the curved optical window (or (elongated) polymer body). Thus, the rotation of the first roller element may transform the (elongated) polymer body configured upstream of the first roller element into the curved optical window downstream of the first roller element. Here, "transforming" may simply refer to the conveying of the (elongated) polymer body, it may (also) refer to the deformation of the (elongated) polymer body, and it may (also) refer to the extrusion of the (elongated) polymer body.

[0024] In particular, the rotational speed (and / or torque) may be selected such that there is no slippage between the polymer material and the first roller element. The speed at which the polymer body may be conveyed downstream of the first roller element may depend on how ductile (or tough) the polymer body may be. Thus, this may mean that a controllable rotational speed (and / or torque) may be selected depending on the temperature of the polymer body.

[0025] The terms "upstream" and "downstream" refer to the arrangement of items or features relative to the first roller element, where, relative to the position of the first roller element, a position closer to the (elongated) polymer body is "upstream" and a position closer to the curved optical window is "downstream".

[0026] Furthermore, in embodiments, the actuator may be configured to extrude the (elongated) polymer body between the first roller elements, i.e., the actuator may perform a pulling action (or a pushing action (or "feeding")) on the (elongated) polymer body, which provides a curved optical window as the curved optical window is extruded between the first roller elements. Note that there may be embodiments in which only such an actuator (which pulls or pushes the polymer material) may be present, without an actuator rotating the first roller element. Thus, the first roller element in these embodiments may rotate due to the absence of slip between the polymer material and the first roller element. As mentioned before, embodiments of the system may (only) include an actuator rotating the first roller element, without any additional actuator configured to push (or pull) the polymer material. As an additional functionality, embodiments of the system may (also) include an actuator configured to translate (or convey) the first roller element upstream (as opposed to conveying the polymer material downstream). And further, in embodiments, a combination of an actuator conveying the first roller element upstream and an actuator conveying the (elongated) polymer body simultaneously downstream may be possible. Thus, in this manner, a number of embodiments may be configured which perform the function of conveying the polymer material and the first roller element relative to each other.

[0027] Furthermore, in an embodiment, in addition to the above-mentioned actuators, there may be additional actuators to control the rotation of one or more additional roller elements. Note that the actuators are not limited to (only) the conveying roller elements (the first roller element and the additional roller elements). Instead, in an embodiment, the actuators may (also) be used to control the position of a heating element comprised by the heating system (see further below). For example, the actuators may in particular be used to control the position of an optional blower.

[0028] Thus, in summary, the system may include one or more (such as in particular multiple) actuators, which may perform the function of providing the desired geometry to the curved optical window. Furthermore, the actuator system may include the one or more actuators. The actuator system may in particular control each individual actuator of the individual actuators included by the actuator system. Thus, in an embodiment, the actuator system may be configured to control (i) the mutual angle (α1) and (ii) the rotational speed of at least one of the first roller elements. Furthermore, in an embodiment, the actuator system may individually control the rotational speed (and / or torque) of the first roller elements. Thus, the rotational speed (and / or torque) of one of the first roller elements may be configured to be different from the rotational speed (and / or torque) of one of the other first roller elements. Note that in such an embodiment, the rotational speed (and / or torque) may be selected to facilitate the transport of the polymer body downstream of the first roller element so that there is no slip between the first roller element and the (elongated) polymer body.

[0029] In an embodiment, the system may include a heating system configured to heat the (elongated) polymer body. Heating may make the polymer material more ductile, and / or (also) may make the polymer material more tough. Thus, heating may provide the advantage of reducing the energy input required by the actuator to convert the (elongated) polymer body into the curved optical window. In particular, the heating system may be configured to heat the polymer material to a processing temperature T p , where T p is a temperature higher than the temperature at which the polymer material transforms from a (relatively more) brittle material to a (relatively more) tough (or ductile) material.In an embodiment, the heating may be provided via the first roller element, ie the heating system may heat the first roller element and thereby heat the polymer material.

[0030] Furthermore, in an embodiment, the heating system may include a blower. In particular, the blower may be configured to blow hot air on the polymer material. In an embodiment, these blowers may be configured near the first roller element. Thus, the blower may be configured upstream of the first roller element (closer to the (elongated) polymer body). Alternatively, in an embodiment, the blower may be configured downstream of the first roller element (closer to the curved optical window). In particular, the heating system may include more than one blower, wherein the position of one or more blowers may be individually controlled. And furthermore, in an embodiment, the blower may be configured to blow hot air on the first roller element. Furthermore, in an embodiment, the heating system may include more than one blower.

[0031] Alternatively or additionally, the heating system may comprise one or more electric heaters.Such heaters may be used to generate IR radiation for heating the polymer material.

[0032] Accordingly, in embodiments, the first roller element may comprise a material that may be resistant to heat. Alternatively, in embodiments, the first roller element may comprise an electrically conductive material. Such a material may in particular provide the advantage of heating the first roller element by passing an electric current through the first roller element. Thus, in embodiments, the first roller element may be heated by blowing hot air over the first roller element, or by passing an electric current through the first roller element to heat the first roller element, or a combination thereof.

[0033] In an embodiment, one or more systems such as a heating system and an actuator system may be individually controlled by the control system. Thus, in this way, the control system may in particular control the actuator system and thereby control the mutual angle (α1), the rotational speed and / or the torque of the first roller element. Additionally or alternatively, in an embodiment, the control system may control the heating system and thereby control the heat provided to the polymer material or the first roller element or both. Thus, in an embodiment, the control system may be configured to control the actuator system and the heating system so that at least a portion of the (elongated) polymer body is heated (using the heating system) and bent (in particular by controlling the mutual angle (α1) and the rotational speed of the first roller element) into a curved optical window while being conveyed between the first roller elements.

[0034] Thus, in summary, the system may in particular comprise a set of first roller elements, an actuator system, a heating system and a control system.

[0035] In an embodiment, the thickness (h 1 ) can be heated and bent into a curved optical window having a radius (r 1 ), when the radius is less than (r1 )'s minimum radius (r m ) has the maximum height (h x ) and at a radius greater than (r 1 )'s maximum radius (r x ) has the minimum height (h m In an embodiment, the curved optical window may have a radius (r 1 ), however this does not limit the curved optical window to a circular geometry.

[0036] As mentioned before, the curved optical window may be curved in one or more directions, in particular, along the axis of the curved polymer diffuser. One way of defining the axis of the optical window may be that the axis is a line passing through the centroid of a cross section of the curved optical window along the (entire) length of the curved optical window. In embodiments, the curvature of the axis (and therefore the optical window) may be in two directions, i.e. the curved optical window may be curved upwards or downwards (when viewed from the front), or may be curved to the left or right (when viewed from above). Furthermore, in embodiments, the curved optical window may have a zigzag configuration, wherein the axis of the curved optical window may include multiple curves such as in the trajectory of a zigzag river. For clarity, "front" refers to the direction in which the curved optical window is viewed in the direction in which the curved optical window is extruded or conveyed, i.e., if a viewer were to view the system, the curved optical window would be conveyed towards the viewer (in a front view). Thus, other directional views such as top, bottom, left and right may be defined relative to the front view.

[0037] Therefore, in an embodiment, the radius of curvature (r 1 ) may vary along its axis. In embodiments, a cross-section of the curved optical window (perpendicular to the axis or when viewed from the front) may be defined by a left edge, a right edge, a top surface, and a bottom surface. The radius of curvature (r 1 ) may in particular be measured from a point which is the center of the cross section. In an embodiment, this may be the midpoint between the left edge and the right edge. Furthermore, in an embodiment, the shape of the cross section of the curved optical window may be a polygon. However, in other embodiments, the shape of the cross section of the curved optical window may be different from a polygon, such as a curved cross section or a cross section of an irregular (or amorphous) shape. Thus, in such an embodiment, the radius may be measured from the centroid of the cross section. In an embodiment, the edge or surface of the curved optical window may (also) be curved. Note that the curvature of the cross section described here is different from the curvature of the axis of the curved optical window.

[0038] In cross section, the two edges (left and right) may each have a radius of curvature greater than (r 1 )’s radius of curvature (r x) and less than the radius of curvature (r 1 )’s radius of curvature (r m ). In addition, in embodiments, the height (or thickness) of the curved optical window can vary over the cross section, i.e., the height of the curved optical window can vary when moving from one edge to another. In embodiments, the curved optical window can be at a maximum radius of curvature (r x ) has the minimum height (h m ). In addition, in an embodiment, the curved optical window can be at a minimum radius of curvature (r m ) has the maximum height (h x ). However, in an embodiment, the following may apply, where 0.9≤h x / h 1 ≤1, and where 0.7≤h m / h x < 1. Note that, in particular, h x can be equal to h 1 , i.e. the maximum thickness of the curved optical window may be equal to the thickness of the (elongated) polymer body. However, in contrast, the minimum thickness may in particular be lower than the thickness of the (elongated) polymer body. In an embodiment, the variation in thickness (or height) of the curved optical window may be within 30%, in particular within 15%, such as within 5%. The variation here refers to the difference between the maximum height and the minimum height of the curved optical window.

[0039] Therefore, in an embodiment, the control system can be configured to control the actuator system and the heating system so that the thickness (h 1 ) is heated while being conveyed between the first roller elements and is bent into a curved optical window having a radius (r 1 ), when the radius is less than (r 1 )'s minimum radius (r m ) has the maximum height (h x ), and at a radius greater than (r 1 )'s maximum radius (r x ) has the minimum height (h m );where 0.9≤h x / h 1 ≤1, and where 0.7≤h m / h x <1. Furthermore, in embodiments, the maximum height of the curved polymer diffuser may be equal to the height of the (elongated) polymer body, i.e. h x / h 1 =1. In addition, in an embodiment, the minimum height of the curved optical window can be set according to 0.7≤h m / h x≤1, such as 0.8≤h m / h x ≤1, especially 0.85≤h m / h x In particular, the (elongated) polymer body may have a thickness (h) selected from the range of 1 mm-10 mm, such as 1 mm-6 mm, in particular 1 mm-3 mm. 1 ). In addition, in an embodiment, the length of the first roller element can be equal to the width (W) of the curved optical window, wherein the width (W) of the roller can be defined as r x -r m .

[0040] In an embodiment, the mutual roll angle (α1) can be controllable between +5° (such as +2°, in particular +1°) and -5° (such as -2°, in particular -1°) relative to the parallel arranged rotation axis (A1). In particular, there can be more than one first roller element, such as two first roller elements. Therefore, the mutual angle (α1) can be measured in the counterclockwise direction from the "first" first roller element to the "second" first roller element. Note that the phrase "controllable between angles" means that the mutual roll angle (α1) is controlled between 0° and α1. Therefore, in an embodiment, the mutual roll angle (α1) can be controllable according to 0°≤α1≤±5°, such as 0°≤α1≤±2°, in particular 0°≤α1≤±1°. The meaning of the symbols "+" and "-" are described below.

[0041] It must be noted that the first roller element may have a base and a tip, wherein the "base" refers to a portion of the first roller element that may be proximal to the mechanical connection between the first roller element and one or more actuators, and the "tip" refers to the end of the first roller element that is distal to where the actuator is connected to the first roller element (i.e., the portion on the end of the roller along the rotation axis A1). Distinguishing between the base and the tip is useful in defining the mutual angle (α1). In particular, if the rotation axes (A1) of the "first" first roller element and the "second" first roller element intersect at a point that is closer to the base of the first roller element (than to the tip), the mutual angle (α1) is measured as positive. Similarly, if the rotation axes (A1) of the "first" first roller element and the "second" first roller element intersect at a point that is closer to the tip of the first roller element (than to the base), the mutual angle (α1) is measured as negative.

[0042] The curved optical window can be curved to the right or left according to a positive or negative mutual roll angle (α1) (when viewed from the front). In particular, the curved optical window can be curved away from the minimum height (h m). This is because excess polymer material in the portion of the (elongated) polymer body that experiences height reduction can be accommodated in the portion of the curved optical window that has a larger radius. Thus, if the curved optical window has a minimum height (h m ), then the curved optical window can be bent to the right, and vice versa. Therefore, by changing the mutual angle (such as between positive and negative mutual roll angles (α1)), the direction in which the curved optical window is bent can be controlled. Therefore, the symbols "+" and "-" indicate the configuration of the roller elements and do not indicate positive / negative angle measurements.

[0043] In an embodiment, the (elongated) polymer body may comprise a polymer material, wherein scattering particles are embedded in the polymer material. Thus, in an embodiment, the curved optical window may (also) comprise scattering particles. Such particles may in particular scatter an incident light beam and thus provide diffuse light. Thus, in an embodiment, the curved optical window may comprise a curved polymer diffuser.

[0044] The obtained effect is a diffuser (for use in a light generating system) with improved optical properties (eg in terms of shape, appearance and / or diffusivity).

[0045] In an embodiment, the system may include a control system. In particular, the control system may be configured to control the actuator system so that the radius (r 1 ) is at least 100 mm, such as at least 150 mm, such as at least 300 mm, in particular at least 1000 mm, such as 10000 mm. The control system may in particular control the actuator system, and thus the actuator. Thus, the control system may be used to change the radius of curvature (r ) by varying (i) the rotation speed of the first roller element, or (ii) the torque of the first roller element, or (iii) the mutual angle (α1) between the two first roller elements, or a combination thereof. 1 ). In particular, the radius of curvature of the curved optical window (r 1 ) can be varied during operation by varying the mutual angle (α1). Thus, in embodiments, the curved optical window can have different radii (r ) along the axis of the curved optical window. 1 ). Furthermore, in an embodiment, the control system can also be used to change the curvature direction of the curved optical window.

[0046] In an embodiment, the system may further comprise one or more guiding elements. In particular, the guiding elements may be configured at one or both sides of the set of first roller elements. Here, the side of the roller element may be similar to the side (or edge) of the curved optical window. Thus, the guiding element may be configured in particular on the left or right side (when viewed from the front) of the curved optical window. In particular, the guiding element may contact the curved optical window at these sides so that there is no slippage between the curved optical window and the guiding element. More particularly, the one or more guiding elements may comprise a guiding roller. And further, the one or more guiding elements may contact the first roller element to form a polygonal shaped opening. Typically, in an embodiment, this may be in the shape of a trapezoid, i.e. one edge is smaller than the planar cross-section of the other edge, however, other shapes may also be conceivable in an embodiment. In an embodiment, the polymer body may be extruded downstream via the opening so that the curved optical window has the same cross-section as the opening described herein.

[0047] In an embodiment, the first roller element may transform the (elongated) polymer body by contacting the (elongated) polymer body from a plane above and below the polymer material (when viewed from the front). However, this provides limited control in shaping the left and right edges (when viewed from the front) of the curved optical window. Therefore, in an embodiment, one or more guiding elements configured at the sides of the curved optical window can provide a curved optical window with particularly flat edges or sides. However, in other embodiments, the guiding element may also have other shapes (e.g. a spindle shape), which (also) can provide a curved optical window with curved sides. And further, embodiments may include combinations of guiding elements of different shapes. Therefore, in an embodiment, the curved optical window may include a flat side and a curved other side. Therefore, in this way, embodiments of the system can be envisioned, in which the guiding elements can be selected so that multiple cross-sectional shapes are achieved. In addition, such an embodiment prevents additional polymer material from accumulating on these sides of the curved optical window. In an embodiment, one or more guiding elements may be configured so that there is no slippage between the guiding element and the curved optical window (or the (elongated) polymer body).

[0048] In embodiments, the first roller element and / or the actuator system may be configured such that the rotational speeds of the first roller elements of the system are the same when in operation. In embodiments, the speed of the first roller element may affect the vertical direction (when viewed from the front) in which the curved optical window may be bent. More material may be conveyed between first roller elements at higher rotational speeds. Thus, in embodiments, in a configuration in which the "first" first roller element is configured below the "second" first roller element, the curved optical window may be bent upward (when viewed from the front) by increasing the rotational speed of the "first" first roller element compared to the "second" first roller element. Similarly, by increasing the rotational speed of the "second" first roller element relative to the "first" first roller element, the curved optical window may be bent downward in particular. In embodiments, the degree of bending may also be controlled by the relative difference in speed between the (two) first roller elements. Thus, in embodiments, the curvature of the curved optical window in the vertical direction (when viewed from the front) may be controlled according to the speed of the first roller element. Thus, in embodiments, by configuring the rotational speeds of the first roller elements to be the same during operation, a substantially planar curved optical window may be provided.

[0049] In particular, in an embodiment, the first roller elements may have substantially the same size, in particular in terms of diameter. Thus, the first roller elements and / or the actuator system may be configured such that the rotational speeds of the first roller elements of the system are the same when in operation. However, if the first roller elements have different sizes, in particular in terms of diameter, in an embodiment, the first roller elements and / or the actuator system may be configured such that the angular velocities of the first roller elements of the system are the same when in operation. In this way, the translational speeds at both faces of the polymer body between the first roller elements may be substantially the same.

[0050] As mentioned before, polymer materials can be heated above the transition temperature T t Toughness and ductility are properties of a material that define the ease with which the material can be drawn into a wire, but more specifically undergo plastic deformation. In particular, polymer materials can be tough and ductile when heated. Transition temperature T t The temperature may in particular be a temperature above which the polymer material may be sufficiently plastic such that it may be shaped into a curved optical window using the system. Thus, in an embodiment, the heating system may be configured to heat the polymer material (i.e. the (elongated) polymer body) to a temperature above T ttemperature. Furthermore, in an embodiment, the heating system may be configured to heat the first roller element. Optionally, in an embodiment, the heating system may (also) be configured to heat one or more guide elements. Thus, in this way, heat may be transferred from the first roller element (and / or the guide element) to the (elongated) polymer body by conduction. Alternatively, as mentioned before, the heating element may (also) comprise a blower, which may be configured to blow hot gas onto the surface of the one or more first rollers, or the guide element, or the polymer material, or a combination thereof. In an embodiment, the transition temperature T t It may be the glass transition temperature.

[0051] In another aspect, the present invention may provide a method for producing a curved optical window from a (slender) polymer body using a set of first roller elements. In particular, the first roller element may have a rotation axis (A1). More particularly, the first roller element may be configured to be tiltable, wherein the rotation axis (A1) has a mutual angle (α1). In an embodiment, the angle between two first roller elements may be controllable, i.e. it may be changed. In particular, the method may include conveying the (slender) polymer body between two first roller elements configured at a mutual angle (α1), thereby bending the (slender) polymer body into a curved optical window. Furthermore, in an embodiment, the method may include controlling the radius of curvature of the curved optical window according to the rotation speed (and / or torque) of one or more first roller elements. In an embodiment, the method may include individually changing the rotation speed (and / or torque) of the first roller elements.

[0052] Furthermore, in an embodiment, the method may include heating the polymer material, such as heating to a transition temperature T t In particular, the method may comprise heating the first roller element or the additional roller element or both. Additionally or alternatively, the method may comprise heating the first roller element and / or the additional roller element and / or the polymer material by means of a blower (which blows hot gas). The polymer material is heated to a processing temperature T p The polymer material may be made ductile, thereby making it easier to deform. In an embodiment, the method may include conveying the (elongated) polymer body between first roller elements and heating the (elongated) polymer body between the first roller elements. In particular, the method may include controlling (i) a mutual angle (α1) and (ii) a rotation speed of at least one of the first roller elements to provide a curved optical window.

[0053] In an embodiment, the method may comprise producing a curved optical window from a (slender) polymer body. Furthermore, in an embodiment, the method may in particular comprise providing a curved optical window from a coil (or spool) of polymer material, another curved optical window or a solid block of polymer material.

[0054] Therefore, in a specific embodiment, the present invention may provide a method for producing a curved optical window from a (slender) polymer body using a collection of first roller elements; wherein the first roller elements have a rotation axis (A1) (wherein the first roller elements are configured to be tiltable), wherein the rotation axis (A1) has a controllable mutual angle (α1); wherein the method includes conveying the (slender) polymer body between the first roller elements and heating the (slender) polymer body between the first roller elements, controlling (i) the mutual angle (α1) and (ii) the rotation speed of at least one of the first roller elements to provide a curved optical window.

[0055] As mentioned before, in an embodiment, the method may include conveying the (elongated) polymer body (having a thickness (h 1 )) and heating the (elongated) polymer body between the first roller elements, controlling (i) the mutual angle (α1) and (ii) the rotation speed of at least one of the first roller elements to provide a curved optical window having a radius (r 1 ), when the radius is less than (r 1 )'s minimum radius (r m ) has the maximum height (h x ) and is greater than the radius (r 1 )'s maximum radius (r x ) has the minimum height (h m ). In addition, in particular, the following may apply, where 0.9≤h x / h 1 ≤1, and where 0.7≤h m / h x <1. Furthermore, in an embodiment, the method may include providing a curved optical window such that h x / h 1 =1 and 0.85≤h m / h x ≤0.95. Thus, in an embodiment, the method may include delivering a curved optical window such that it can be curved at a maximum radius of curvature (r x ) has the minimum height (h m ) and at the minimum radius of curvature (r m ) has the maximum height (h x ).

[0056] Furthermore, in an embodiment, the method may comprise providing a curved optical window such that the maximum height of the curved polymer diffuser may be equal to the height of the (elongated) polymer body, ie h x / h 1=1. In particular, the method may include providing a curved optical window, wherein the minimum height of the curved optical window may be in accordance with a condition such as 0.7≤h m / h x ≤1, especially 0.8≤h m / h x ≤1, such as 0.85≤h m / h x The range of ≤0.95.

[0057] Furthermore, the method may comprise providing a curved optical window such that the (elongated) polymer body may have a thickness (h) selected from the range of 1 mm-10 mm, such as 1 mm-6 mm, in particular 1 mm-3 mm. 1 ). In an embodiment, the method may include limiting the variation of the thickness (or height) of the polymer material to within 30%, in particular within 20%, such as within 10%. The variation here refers to the difference between the maximum height and the minimum height of the curved optical window. Furthermore, in an embodiment, the method may include providing a curved optical window with a fixed width (W) by selecting a length of the first roller element equal to the width (W) of the curved optical window, such as W=r x -r m As mentioned previously, in embodiments, the length of the first roller element may be equal to the width (W) of the curved optical window, where the width (W) of the roller may be defined as r x -r m .

[0058] In an embodiment, the method may include controlling the mutual roll angle (α1) between +5° (such as +2°, in particular +1°) and -5° (in particular -2°, such as -1°) relative to the parallel configured rotation axes (A1). The definitions of positive angles and negative angles are further described above. Therefore, in an embodiment, the method may include controlling the curvature direction of the curved optical window to vary between a positive mutual roll angle (α1) and a negative mutual roll angle (α1). In addition, the method may include controlling the radius of curvature of the curved optical window by varying the mutual roll angle (α1). A larger mutual roll angle (α1) may result in a smaller radius (r 1 ).

[0059] Thus, in an embodiment, the method may comprise controlling the mutual angle (α1) and the rotational speed of at least one of the first roller elements to provide a radius (r 1 ) of at least 100 mm, such as at least 150 mm, such as at least 300 mm, in particular at least 1000 mm, such as at least 10000 mm. 1). In particular, the method may comprise varying the mutual angle (α1) during operation and thereby providing a curved optical window having different radii (r1) along an axis of the curved optical window.

[0060] In embodiments, the method may further comprise the use of one or more guiding elements configured at one or both sides of the set of first roller elements. In particular, the one or more guiding elements may comprise guiding rollers. In embodiments, the method may comprise the use of one or more guiding elements configured at these sides of the curved optical window to provide a curved optical window with particularly flat edges or sides. However, in other embodiments, guiding elements may also be used to provide a curved optical window with curved sides. And further, in embodiments, the method may comprise providing a curved optical window with a combination of flat sides and curved sides. Such embodiments may prevent additional polymer material from accumulating on these sides of the curved optical window. In addition, such embodiments may contact the sides of the curved optical window and thus prevent slippage between the curved optical window and the guiding elements. In embodiments, the method may comprise configuring the one or more guiding elements such that there is no slippage between the guiding elements and the curved optical window (or the (elongated) polymer body). And further, the method may particularly comprise forming a bounded opening (of a desired cross section) by contacting the first roller element and the guiding element, such that the extruded curved optical window has the same desired cross section.

[0061] In an embodiment, the method may include maintaining the rotation speed of the first roller element the same. Maintaining the same rotation speed may result in an equal amount of polymer material (or (elongated) polymer body) being conveyed near one or more first roller elements. Thus, in an embodiment, by maintaining the rotation speed of the first roller element the same, the method may provide a curved optical window that may have no curvature in the vertical direction (when viewed from the front). Alternatively, in an embodiment, the method may provide a curved optical window, wherein the curved optical window may be bent upwards by increasing the rotation speed of the first roller element in contact with the bottom surface of the (elongated) polymer body. In a similar manner, the method may in particular provide a curved optical window, wherein the curved optical window may be bent downwards by increasing the rotation speed of the first roller element in contact with the top surface of the (elongated) polymer body.

[0062] In an embodiment, the polymer material may have a glass transition temperature T g Here, a transition is a gradual change in the state of matter (occurring in an amorphous material) in which a material (such as a polymer material) can change from a relatively hard and brittle state to a relatively viscous and rubbery state. The temperature range over which this occurs can be defined as the glass transition temperature T g The temperature range T g Below the melting temperature Tm , melting temperature T m is the temperature at which a substance changes from a solid to a liquid state. Thus, in an embodiment, the method may comprise heating the (elongated) polymer body to a temperature above the glass transition temperature T g The processing temperature T p , where 0℃ <t p -t g ≤50°C. Heating the (elongated) polymer body may make the polymer material more tough and / or ductile, thereby reducing the torque required to transform the (elongated) polymer body into a curved optical window. Thus, in particular, the method may comprise heating the polymer material to a processing temperature T p , where T p Above the glass transition temperature T g , but not higher than the glass transition temperature T g 50°C or more. In particular, the method may comprise heating the (elongated) polymer body by means of heating the one or more first roller elements. Additionally or alternatively, in an embodiment, the method may comprise heating the polymer material (i.e. the (elongated) polymer body or the curved optical window) by means of a blower.

[0063] In an embodiment, the polymer material may include one or more of PMMA and PC. In addition, in an embodiment, the polymer material may include a (thermoplastic) polymer selected from the group consisting of ABS (acrylonitrile butadiene styrene), nylon (or polyamide), acetate (or cellulose), PLA (polylactic acid), terephthalate (such as PET polyethylene terephthalate), acrylic (polymethacrylate, organic glass, polymethyl methacrylate PMMA), polypropylene (or polypropylene polypropene), polycarbonate (PC), polystyrene (PS), PE (such as expanded-high impact-polyethylene (or polyethylene), low density (LDPE), high density (HDPE)), PVC (polyvinyl chloride) Polychloroethene, such as thermoplastic elastomers based on copolyester elastomers, polyurethane elastomers, polyamide elastomers, polyolefin-based elastomers, styrene-based elastomers, etc. Elastomers (especially thermoplastic elastomers) may be particularly interesting because they are flexible. Thermoplastic elastomers may include one or more of the following: styrenic block copolymers (TPS (TPE-s)), thermoplastic polyolefin elastomers (TPO (TPE-o)), thermoplastic vulcanizates (TPV (TPE-v or TPV)), thermoplastic polyurethanes (TPU (TPU)), thermoplastic copolyesters (TPC (TPE-E)) and thermoplastic polyamides (TPA (TPE-A)).

[0064] Suitable thermoplastic materials such as those also mentioned in WO2017 / 040893 may include one or more of the following: polyacetals (e.g., polyoxyethylene and polyoxymethylene), poly(C 1-6 alkyl) acrylates, polyacrylamides, polyamides (e.g., aliphatic polyamides, polyphthalamides, and polyaromatic amides), polyamideimides, polyanhydrides, polyarylates, polyarylethers (e.g., polyphenylene oxide), polyarylether sulfides (e.g., polyphenylene sulfide), polyarylether sulfones (e.g., polyphenylene sulfide), polyarylethersulfones (e.g., polyphenylene sulfone), polybenzothiazoles, polybenzoxazoles, polycarbonates (including polycarbonate copolymers such as polycarbonate-siloxanes, polycarbonate-esters, and polycarbonate-ester-siloxanes), polyesters (e.g., polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyarylates) and polyester copolymers (such as polyester-ethers), polyetheretherketones, polyetherimides (including copolymers such as polyetherimide-siloxane copolymers), polyetherketoneketones, polyetherketones, polyethersulfones, polyimides (including copolymers such as polyimide-siloxane copolymers), poly(C 1-6 The invention can be used in combination with any of the foregoing thermoplastic polymers, such as poly(vinyl alcohol), poly(vinyl ether), poly(vinyl halides), poly(vinyl ketone), poly(vinyl sulfide), poly(vinyl ether), poly(vinyl sulfide), poly(vinyl alcohol), poly(vinyl ester), poly(vinyl ether), poly(vinyl halides), poly(vinyl ketone), poly(vinyl sulfide), poly(vinylidene fluoride), and the like, or a combination comprising at least one of the foregoing thermoplastic polymers. Examples of polyamides may include, but are not limited to, synthetic linear polyamides such as nylon-6,6; nylon-6,9; nylon-6,10; nylon-6,12; nylon-11; nylon-12 and nylon-4,6, preferably nylon 6 and nylon 6,6, or a combination comprising at least one of the foregoing. Polyurethanes that may be used include aliphatic, alicyclic, aromatic, and polycyclic polyurethanes, including those described above. Also useful are poly(C 1-6 Alkyl) acrylate and poly (C 1-6The invention also includes the following polymers: methyl acrylate, ethyl acrylate, acrylamide, methacrylic acid, methyl methacrylate, n-butyl acrylate, ethyl acrylate, etc. In an embodiment, the polyolefin may include one or more of the following: polyethylene, polypropylene, polybutene, polymethylpentene (and copolymers thereof), polynorbornene (and copolymers thereof), poly-1-butene, poly(3-methylbutene), poly(4-methylpentene), and copolymers of ethylene with propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, and 1-octadecene.

[0065] In a specific embodiment, the polymer material may include one or more of the following: polycarbonate (PC), polyethylene (PE), high-density polyethylene (HDPE), polypropylene (PP), polyoxymethylene (POM), polyethylene naphthalate (PEN), styrene-acrylonitrile resin (SAN), polysulfone (PSU), polyphenylene sulfide (PPS) and semi-crystalline polyethylene terephthalate (PET), acrylonitrile-butadiene-styrene (ABS), poly(methyl methacrylate) (PMMA), polystyrene (PS) and styrene-acrylic acid copolymer (SMMA).

[0066] In an embodiment, the (elongated) polymer body may include scattering particles embedded therein. In particular, the scattering particles may include inorganic particles (e.g. one or more of the following: TiO 2 Granules, BaSO 4 Particles and Al 2 O 3 Scattering particles can provide the advantage of scattering light incident on them, thereby providing diffuse lighting. Therefore, in this way, an illumination system including a curved optical window can be particularly useful in providing diffuse lighting. In an embodiment, the size (d) of the scattering particles can be selected from the following range: 10nm-10000nm, such as 20nm-4000nm, in particular 100nm-2000nm, in particular 150nm-1000nm. Therefore, in an embodiment, the curved optical window can include a polymer material in which scattering particles are embedded. The scattering particles can provide the benefit of scattering light incident on these particles, and thus provide diffuse light.

[0067] In another aspect, the present invention can provide a curved optical window having a maximum height (h x )、Minimum height (h m ) and radius (r 1 ). In particular, the thickness of the curved optical window may (when viewed from the front) vary (gradually) from the left edge to the right edge. The radius (r 1) is the radius of curvature of the curved optical window, where r 1 is the curvature of the curved optical window at a point that may be at the center of a cross-section of the curved optical window. 1 can be defined with respect to the centroid of the cross section of the curved optical window. Thus, in an embodiment, it is possible that the radii of curvature at the right and left edges of the curved optical window can be defined, where the maximum radius is r x And the minimum radius is r m The thickness of the curved optical window may vary gradually (ie increase) from one edge to the other, in particular according to: 0.7 ≤ h m / h x <1, such as 0.75≤h m / h x <0.95, especially 0.8≤h m / h x <0.9. Here, h m is the minimum thickness of the curved optical window, and h x is the maximum thickness of the curved optical window. Note that h m / h x cannot be equal to 1, that is, in an embodiment, the curved optical window may not have a uniform thickness. In an embodiment, the minimum height (h m ) can be greater than the radius (r 1 )'s maximum radius (r x ) and the maximum height (h x ) can be smaller than the radius (r 1 )'s minimum radius (r m In particular, the change in thickness may be gradual, ie the change in thickness may be 30%, such as 20%, in particular 10%.

[0068] As mentioned previously, in embodiments, the variation in thickness over a cross section of the optical window may be related to the radius of curvature of the optical window, ie, the ratio h m / h x The reduction can be related to the radius r 1 However, this may be true (only) when the polymer body (over its cross section) has a uniform thickness. Thus, in other embodiments, the polymer body may have a wedge-shaped cross section. Thus, in such embodiments, by using a polymer body of non-uniform cross section (such as a wedge), in particular a curved optical window with an almost uniform cross section may be provided. In such embodiments, h m / h x It can be provided in particular that 0.9≤h m / h x <1, such as 0.95≤hm / h x <1, especially 0.99≤h m / h x <1. This may be particularly advantageous in providing a curved optical window with an almost uniform cross-sectional thickness. Thus, in this way, a uniform illumination may be provided.

[0069] Therefore, in a specific embodiment, the present invention can provide a curved optical window having a maximum height (h x )、Minimum height (h m ) and radius (r 1 );where 0.7≤h m / h x <1, where the thickness (h) of the curved optical window is from the minimum height (h m ) gradually increases to a maximum height (h x ), where the minimum height (h m ) is greater than the radius (r 1 )'s maximum radius (r x ) and the maximum height (h x ) is smaller than the radius (r 1 )'s minimum radius (r m ) at the location; wherein the curved optical window comprises a polymer material.

[0070] In an embodiment, the maximum height (h x ) can be selected from the range of 0.9*1-3mm, such as 0.8*1-3mm, in particular 0.7*1-3mm. In particular, the thickness of the curved optical window can be selected according to 0.7≤h m / h x ≤1, such as 0.85≤h m / h x ≤0.95. In addition, in the embodiment, the radius (r 1 ) may be selected to be at least 100 mm, such as at least 150 mm, such as at least 300 mm. In an embodiment, the radius (r 1 ) can be chosen in particular to be at least 1000 mm, such as at least 10000 mm.

[0071] In embodiments, the polymer material may include one or more of PMMA and PC, and additionally, in embodiments, the polymer material may include other polymers previously described (see further above).

[0072] In an embodiment, the polymer material may include scattering particles embedded therein. Furthermore, as mentioned previously, in an embodiment, the scattering particles may include one or more of inorganic particles and silicone particles. In particular, the size (d) of the scattering particles may be selected from the following range: 10nm-10000nm, such as 20nm-4000nm, in particular 100nm-2000nm, in particular 150nm-1000nm. In an embodiment, the curved optical window may include a curved polymer diffuser. In particular, the curved polymer diffuser (in an embodiment) may include a polymer material, wherein the scattering particles are embedded in the polymer material.

[0073] The effect obtained is a light generating system having the advantage of improved optical properties (eg in terms of shape, appearance and / or diffusivity).

[0074] In an embodiment, the curved optical window may have a first major face and a second major face that define the thickness (h) of the curved optical window. Embodiments of the curved optical window may be configured to transmit most of the light incident on the first major face through the optical window and out via the second major face (with minimal changes to the optical properties of the light). This may be advantageous for high illumination purposes, such as in a workplace. Alternatively, in an embodiment, the curved optical window may provide diffuse light via the second major face (particularly when the curved optical window includes scattering particles), such as for illuminating a wall or a corridor. And further, in an embodiment, the curved optical window may provide a combination of light beams from different parts of the curved optical window and diffuse light. Thus, in an embodiment the optical window may be transparent, and in other embodiments may be translucent.

[0075] Therefore, in an embodiment, when one of the first main surface and the second main surface is irradiated perpendicularly with light in the visible wavelength range, at least 85%, such as 90%, in particular 95%, and more particularly 99% of the light can be transmitted (when the curved optical window (or a portion thereof) is configured to provide a light beam). Alternatively, in an embodiment, when one of the first main surface and the second main surface is irradiated perpendicularly with light in the visible wavelength range, at least 5%, such as 15%, and in particular 25% of the light is reflected (when the curved optical window (or a portion thereof) is configured to provide diffuse light) and at least 20%, such as 30%, such as 50%, and in particular 70% of the light is transmitted. Here, in an embodiment, a portion of the light incident on the first main surface of the curved optical window can be reflected, and another portion of the light incident on the first main surface of the curved optical window can be transmitted. In addition, in an embodiment, the transmitted light can experience scattering within the curved optical window, especially in the presence of scattering particles.

[0076] In another aspect, the present invention may provide a light generating system comprising a housing and a light generating device. In particular, the housing may include a (bent) light exit window. The light generating system may in particular include one or more light generating devices configured within the light generating system. In an embodiment, the number of light generating devices may vary. In addition, in an embodiment, one or more light generating devices may be configured to generate device light. In particular, the device light may be light in the visible wavelength range. However, in an embodiment, one or more light generating devices may be configured to provide device light in the infrared wavelength range. This may be useful in embodiments that may be used for local heating or warming purposes. And in addition, in an embodiment, one or more light generating devices may generate device light in the ultraviolet wavelength range. This may be useful in embodiments that may be configured for disinfection purposes. In an embodiment, the light generating system may include a light exit window. In particular, the device light may escape from the light generating system via the light exit window. In particular, the light exit window may include a bent optical window. In an embodiment, the light exit window may be configured to transmit at least a portion of the device light (to the outside of the housing) and reflect at least a portion of the device light.

[0077] Furthermore, in an embodiment, the light generating system may include one or more optical windows. In a specific embodiment, the light generating system may include two optical windows, wherein the first optical window may be a curved polymer diffuser and the second optical window may be an optical window that is (highly) transmissive to light. Thus, in such an embodiment, light may pass through the first optical window, the second optical window, and then escape via the light exit window.

[0078] Therefore, in a specific embodiment, the present invention may provide a light generating system comprising a housing and a light generating device; wherein the housing comprises a (curved) light exit window; wherein the light generating device is configured to generate device light (having a wavelength in the visible wavelength range), wherein the light exit window comprises a curved optical window as previously defined, wherein the light exit window is configured to transmit at least a portion of the device light (to the outside of the housing) and reflect at least a portion of the device light.

[0079] For example, the light generating system may be part of or may be applied in an office lighting system, a home application system, a shop lighting system, a household lighting system, an accent lighting system, a spotlighting system, a theatre lighting system, a fibre optic application system, a projection system, a self-lighting display system, a pixelated display system, a segmented display system, a warning sign system, a medical lighting application system, an indicator sign system, a decorative lighting system, a portable system, a motor vehicle application, a (outdoor) road lighting system, a city lighting system, a greenhouse lighting system, horticultural lighting, digital projection or LCD backlighting. The light generating system (or luminaire) may be part of or may be applied in, for example, an optical communication system or a disinfection system.

[0080] In an embodiment, the polymer material may include one or more of PMMA and PC. In particular, the polymer material may (also) include other polymers. The polymer materials used in the embodiments of the curved optical window are further discussed above. In an embodiment, the scattering particles may include one or more of inorganic particles and silicone particles. In particular, the size (d) of the scattering particles may be selected from the following range: 10nm-10000nm, such as 20nm-4000nm, in particular 100nm-2000nm, in particular 150nm-1000nm.

[0081] In embodiments, the curved optical window may have a length of at least 4 meters or at least 8 meters.

[0082] The term "visible", "visible light" or "visible emission" and similar terms refer to light with one or more wavelengths in the range of about 380nm-780nm. In this context, UV may particularly refer to a wavelength selected from the range of 190nm-380nm, such as 200nm-380nm.

[0083] In an embodiment, the control system may be configured to control (or operate in an operating mode) one or more sets of light generating devices. Note that the control system referred to here may be different from the control system described previously (which is used to control the system to provide a curved optical window).

[0084] The term "control" and similar terms refer at least in particular to the behavior of determining an element or the operation of a regulatory element. Therefore, "control" and similar terms herein may, for example, refer to the application of behavior (determining the behavior of an element or the operation of a regulatory element) to an element, such as, for example, measuring, displaying, actuating, opening, moving, changing temperature, etc. In addition, the term "control" and similar terms may additionally include monitoring. Therefore, the term "control" and similar terms may include applying behavior to an element, and also include applying behavior to an element and monitoring the element. The control of an element may be accomplished using a control system, which may also be indicated as a "controller". The control system and the element may therefore be functionally coupled at least temporarily or permanently. The element may include a control system. In an embodiment, the control system and the element may not be physically coupled. Control may be accomplished via wired and / or wireless control. The term "control system" may also refer to a plurality of different control systems, which are particularly functionally coupled, and wherein, for example, one control system may be a master control system, and one or more other control systems may be slave control systems. The control system may include a user interface or may be functionally coupled to a user interface.

[0085] The control system may also be configured to receive and execute instructions from a remote control. In an embodiment, the control system may be controlled via an application (App) on a device, such as a portable device, such as a smartphone or I-phone, a tablet, etc. Therefore, the device is not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

[0086] Thus, in an embodiment, the control system may (also) be configured to be controlled by an application on a remote device. In such an embodiment, the control system of the lighting system may be a slave control system or a control in slave mode. For example, the lighting system may be identified with a code, which code is in particular a unique code of the respective lighting system. The control system of the lighting system may be configured to be controlled by an external control system, which accesses the lighting system based on knowledge of the (unique) code (entered via a user interface with an optical sensor (e.g. a QR code reader)). The lighting system may also comprise means for communicating with other systems or devices, such as based on Bluetooth, Thread, WIFI, LiFi, ZigBee, BLE or WiMAX or another wireless technology.

[0087] A system or device or apparatus may perform actions in a "mode" or "operating mode" or "operable mode". The term "operable mode" may also be indicated as a "control mode". Similarly, in a method, actions or phases or steps may be performed in a "mode" or "operating mode" or "operable mode". This does not exclude that a system or device or apparatus may also be adapted to provide another control mode, or a plurality of other control modes. Similarly, this may not exclude that one or more other modes may be performed before and / or after the execution of the mode.

[0088] However, in an embodiment, a control system adapted to provide at least a control mode may be available. If other modes are available, the selection of such modes may in particular be performed via a user interface, but other options (such as performing modes depending on sensor signals or (time) schemes) are also possible. In an embodiment, an operating mode may also refer to a system or device or apparatus that can only be operated in a single operating mode (i.e. "on", without further tunability).

[0089] Therefore, in an embodiment, the control system may perform control according to one or more of an input signal of a user interface, a sensor signal (of a sensor) and a timer. The term "timer" may refer to a clock and / or a predetermined time scheme.

[0090] In yet another aspect, the present invention also provides a lamp or a lamp fixture comprising a light generating system as defined herein. The lamp fixture may also include a housing, an optical element, a shutter, etc. ... The lamp or lamp fixture may also include a housing surrounding the light generating system. The lamp or lamp fixture may include a light window or a housing opening in the housing, through which the system light may escape from the housing. In yet another aspect, the present invention also provides a projection device comprising a light generating system as defined herein. In particular, a projection device or "projector" or "image projector" may be an optical device that projects an image (or moving image) onto a surface such as, for example, a projection screen. The projection device may include one or more light generating systems such as described herein. Therefore, in one aspect, the present invention also provides a light generating device selected from the group of lamps, lamps, projector devices, disinfection devices, photochemical reactors, and optical wireless communication devices, the light generating device including a light generating system as defined herein. The light generating device may include a housing or a carrier configured to accommodate or support one or more elements of the light generating system and, for example, a curved optical window. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference numerals indicate corresponding parts and in which:

[0092] Figure 1A to Figure 1B An embodiment of a system 2000 is schematically depicted.

[0093] Figure 2 One embodiment of a curved optical window 400 is schematically depicted.

[0094] Figure 3 An embodiment of a system 2000 is depicted wherein a (elongated) polymer body 1400 is conveyed through a first roller element 410 to provide a curved optical window 400 .

[0095] Figure 4 One embodiment of a light generating system 1000 is schematically depicted.

[0096] Figure 5 Schematically depicted is one embodiment of a lighting device 1200 comprising the light generating system 1000. The schematic diagrams are not necessarily to scale. DETAILED DESCRIPTION

[0097] Figure 1A Schematically depicted is one embodiment of a system 2000. In particular, the present invention may provide a system 2000 for producing a curved optical window 400 from a (elongated) polymer body 1400. In an embodiment, the system 2000 may include a set of first roller elements 410, an actuator system 500, a heating system 700, and a control system 1500.

[0098] In particular, the first roller element 410 may have a rotation axis A1 (wherein the first roller element 410 is configured to be tiltable), wherein the rotation axis A1 has a controllable mutual angle α1. Furthermore, in an embodiment, the actuator system 500 may be configured to control (i) the mutual angle α1 and (ii) the rotation speed of at least one of the first roller elements 410. The system 2000 may in particular include one or more actuators 510, which may control the rotation speed or torque or the mutual angle. In an embodiment, the actuator 510 may be controlled by the actuator system 500. Furthermore, in an embodiment, the heating system 700 may be configured to heat the (elongated) polymer body 1400. In an embodiment, the control system 1500 is configured to control the actuator system 500 and the heating system 700 so that at least a portion of the (elongated) polymer body 1400 is heated (using the heating system 700) and bent (in particular by controlling the mutual angle α1 and the rotation speed) into a curved optical window 400 while being conveyed between the first roller elements 410.

[0099] In an embodiment, the control system 1500 can be configured to control the actuator system 500 and the heating system 700 so that the1 At least a portion of the (elongated) polymer body 1400 is heated while being conveyed between the first roller elements 410 and is bent into a curved optical window 400 having a radius r 1 , less than the radius r 1 The minimum radius r m The maximum height h x And greater than the radius r 1 The maximum radius r x The minimum height h m ; where 0.9≤h x / h 1 ≤l, and where 0.7≤h m / h x <l。

[0100] In an embodiment, the system 2000 may further include one or more guide elements 420. In particular, the guide elements 420 may be configured at one or both sides of the set of first roller elements 410. In an embodiment, the one or more guide elements 420 may include a guide roller 421. In particular, the guide element 420 and the first roller element 410 may particularly form a bounded opening defining a cross-section, wherein the curved optical window 400 conveyed downstream of the first roller element may include the cross-section.

[0101] In particular, the first roller element 410 and / or the actuator system 500 can be configured so that the rotational speed of the first roller element 410 of the system 2000 is the same when in operation. More particularly, the heating system 700 can be configured to heat the first roller element 410 (and optionally one or more guide elements 420).

[0102] In another aspect, the present invention may provide a method for producing a curved optical window 400 from a (elongated) polymer body 1400 using a set of first roller elements 410. In particular, the first roller elements 410 may have a rotation axis A1 (wherein the first roller elements 410 may be configured to be tiltable). More particularly, the rotation axes A1 may have a controllable mutual angle α1.

[0103] In an embodiment, the method comprises conveying a (slender) polymer body 1400 between first roller elements 410 and heating the (slender) polymer body 1400 between the first roller elements 410, controlling (i) a mutual angle α1 and (ii) a rotation speed of at least one of the first roller elements 410 to provide a curved optical window 400. In addition, in an embodiment, the (slender) polymer body 1400 may have a thickness h 1In particular, the method may include conveying the (elongated) polymer body 1400 between first roller elements 410 and heating the (elongated) polymer body 1400 between the first roller elements 410, controlling (i) a mutual angle α1 and (ii) a rotation speed of at least one of the first roller elements 410 to provide a curved optical window 400 having a radius r1 and a curvature less than the radius r 1 The minimum radius r m The maximum height h x And greater than the radius r 1 The maximum radius r x The minimum height h m , where 0.9≤h x / h 1 ≤1, and where 0.7≤h m / h x <1.

[0104] Furthermore, in an embodiment, the method may further include using one or more guide elements 420 configured at one or both sides of the set of first roller elements 410. More specifically, the one or more guide elements 420 may include a guide roller 421.

[0105] In an embodiment, the method may include maintaining the same rotation speed of the first roller element 410. In particular, the (elongated) polymer body 1400 may include a polymer material 1401, wherein the scattering particles 1402 are embedded in the polymer material 1401. More particularly, the polymer material 1401 may have a glass transition temperature T g , wherein the method comprises heating the (elongated) polymer body 1400 to a temperature above the transition temperature T g The processing temperature T p , where 0℃ <t p -t g ≤50℃.

[0106] In particular, the polymer material 1401 may include one or more of PMMA and PC. Furthermore, in an embodiment, the scattering particles 1402 may include one or more of inorganic particles and silicone particles. In particular, the scattering particles 1402 may have a size (d) selected from the range of 20nm-4000nm (in particular 100nm-2000nm). And further, in an embodiment, the method includes heating the first roller element 410.

[0107] Figure 1B An embodiment of the system is schematically depicted. In particular, the configuration of the first roller element in the embodiment is depicted.

[0108] In an embodiment, the method may provide a curved optical window, wherein h x / h 1 =1 and 0.85≤h m / h x ≤0.95. In particular, the thickness h 1 Can be selected from the range of 1mm-3mm. In addition, in an embodiment, the method may include controlling the mutual angle α1 of the rollers between +2° and -2° relative to the parallel arranged rotation axis A1. In an embodiment, the method may include controlling the mutual angle α1 and the rotation speed of at least one of the first roller elements 410 to provide a radius r1, the radius r1 is selected to be at least 100mm, such as at least 150mm, such as at least 300mm, such as in particular 1000mm, such as at least 10000mm.

[0109] In an embodiment, the method may include controlling the mutual angle α1 of the rollers between +5° (such as +2°, in particular +1°) and -5° (in particular -2°, such as -1°) relative to the parallel configured rotation axis A1. The definition of positive angles and negative angles is further described above. Therefore, in an embodiment, the method may include controlling the curvature direction of the curved optical window 400 by changing between a positive mutual roller angle and a negative mutual roller angle α1. In addition, the method may include controlling the radius of curvature of the curved optical window by changing the mutual roller angle α1. A larger mutual roller angle α1 can result in a smaller radius r1 of the curved optical window.

[0110] Thus, embodiment (I) depicts an embodiment wherein the “second” first roller element 410 is configured at a positive angle α1 relative to the “first” first roller element 410. Embodiment (II) depicts an embodiment wherein the “second” first roller element 410 is configured at a negative angle α1 relative to the “first” first roller element 410. Embodiment (III) depicts an embodiment wherein the “first” first roller element 410 is configured at a positive angle α1 relative to the “second” first roller element 410. Embodiment (III) depicts an embodiment wherein the “first” first roller element 410 is configured at a positive angle α1 relative to the “second” first roller element 410.

[0111] Figure 2 One embodiment of a curved optical window 400 is schematically depicted. In another aspect, the present invention provides a curved optical window having a maximum height h x , minimum height h m and a curved optical window 400 of radius r1. In particular, 0.7≤h m / h x <1, wherein the thickness h of the curved optical window 400 is from the minimum height h m Gradually increases to a maximum height hx , where the minimum height h m At a radius greater than r 1 The maximum radius r x and the maximum height h x Less than radius r 1 The minimum radius r m In particular, the curved optical window 400 may include a polymer material 1401, wherein the scattering particles 1402 are embedded in the polymer material 1401. In an embodiment, the maximum height h x is selected from the range of 0.9*1-3 mm. More particularly, 0.85≤h m / h x ≤0.95. In particular, the curved optical window may have a width W, and the width W may be equal to the difference between the maximum radius and the minimum radius of the curved optical window, that is, W=r x -r m Note that the width of the curved optical window may in particular be equal to the width of the first roller element.

[0112] Furthermore, in the embodiment, h x / h 1 =1 and 0.85≤h m / h x ≤0.95. In particular, the mutual angle α1 of the rollers can be controllable between +2° and -2° relative to the parallel arranged rotation axis A1. In particular, the thickness h 1 It can be selected from the range of 1mm-3mm.

[0113] Furthermore, in an embodiment, the radius r1 may be selected to be at least 100 mm, such as at least 150 mm. In particular, the polymer material 1401 may include one or more of PMMA and PC. More particularly, the scattering particles 1402 may include one or more of inorganic particles and silicone particles, wherein the scattering particles 1402 have a size (d) selected from the range of 20 nm-4000 nm (in particular 100 nm-2000 nm).

[0114] In an embodiment, the curved optical window 400 may have a first main face 401 and a second main face 402 defining a thickness h of the curved optical window 400. In particular, in the case where one of the first main face 401 and the second main face 402 is irradiated perpendicularly with light in the visible wavelength range, at least 15% of the light may be reflected and at least 50% of the light may be transmitted. Note that in an embodiment, the extent to which light is reflected or transmitted may vary depending on the choice of polymer material. In an embodiment, where the curved optical window (or a portion thereof) is configured to provide a light beam (such as for illumination), the transmittance of the polymer material may (even) be at least 85%, such as at least 90%, in particular at least 95%, more in particular at least 99%. Therefore, in such an embodiment the extent to which light is reflected may be at most 15%, such as at most 10%, in particular at most 5%, more in particular at most 1%.

[0115] Figure 3 An embodiment of a system 2000 is schematically depicted, wherein a (elongated) polymer body 1400 may be conveyed downstream of a first roller element 410 to provide a curved optical window 400 .

[0116] Embodiment I schematically depicts an embodiment in which the (elongated) polymer body 1400 may be configured as a spool or coil of polymer material. In particular, the (elongated) polymer body 1400 may include polymer material 1401. Furthermore, in embodiments, the polymer material may include scattering particles embedded therein. This may be advantageous in terms of scattering light, such as in embodiments of curved optical windows comprising curved polymer diffusers. However, in other embodiments, the curved optical window may not have embedded particles, such as in transparent curved optical windows. In embodiments, the first roller element 410 may have a controllable mutual angle α1 (as indicated in FIG. 1b ). Thus, in embodiments, the curved optical window may be provided by conveying the (elongated) polymer body downstream of the first roller element. In particular, the curved optical window 400 may be provided at a radius less than r 1 The minimum radius r m The maximum height h x , and at a radius greater than r 1 The maximum radius r x The minimum height h m In the embodiment, 0.9≤h x / h 1 ≤1. In addition, in the embodiment 0.7≤h m / h x <1.

[0117] Embodiment II schematically depicts an embodiment in which the (elongated) polymer body 1400 can be configured to be substantially flat or straight (i.e., the (elongated) polymer body can include a linear axis). As described in Embodiment I, the (elongated) polymer body 1400 can be conveyed downstream of the first roller element 410 to provide a curved optical window 400. In particular, the curved optical window can have a first major face 401 and a second major face 402. More particularly, the first roller element 410 can have a controllable mutual angle (α1) such that a curved optical window with a radius r1 can be provided. In particular, the curved optical window 400 can be provided at a radius less than the radius r 1 The minimum radius r m The maximum height h x , and at a radius greater than r 1 The maximum radius r x The minimum height h m Furthermore, in an embodiment, the curved polymer window may have a width W=r x -r m In this embodiment, the curved optical window may not have particles embedded therein.

[0118] Still further, in an embodiment, the control system 1500 may be configured to control the actuator system 500 such that the radius r1 is at least 150 mm.

[0119] Figure 4 Schematically depicted is one embodiment of a light generating system 1000. In another aspect, the invention may provide a light generating system 1000 comprising a housing 1040 and a light generating device 100. In particular, the housing 1040 may comprise a (curved) light exit window 1050. More particularly, the light generating device 100 may be configured to generate device light 101 (having a wavelength in the visible wavelength range).

[0120] Furthermore, in an embodiment, the light exit window 1050 may comprise a curved optical window 400 , wherein the light exit window 1050 may be configured to transmit at least a portion of the device light 101 (to the outside of the housing 1040 ) and to reflect at least a portion of the device light 101 .

[0121] In addition, in an embodiment, the polymer material 1401 may include one or more of PMMA and PC. In particular, the scattering particles 1402 may include one or more of inorganic particles and silicone particles, wherein the scattering particles 1402 may have a size (d) selected from the range of 20nm-4000nm (in particular, 100nm-2000nm).

[0122] Figure 5An embodiment of a luminaire 2 comprising a light generating system 1000 as described above is schematically depicted. Reference numeral 301 indicates a user interface, which may be functionally coupled to a control system 300, which is comprised by or functionally coupled to the light generating system 1000. Note that the control system 300 in the embodiment may be used to control the light generating system (the control system 300 is different from the control system 1500 (the control system 1500 may be used by the system 2000 to provide a curved optical window)). Thus, Figure 5 Schematically depicted is an embodiment of a lighting device 1200, the lighting device 1200 being selected from the group of a lamp 1, a lamp fixture 2, a projector device 3, a disinfection device, a photochemical reactor, and an optical wireless communication device, the lighting device 1200 comprising a light generating system 1000 as described herein. In an embodiment, such a lighting device may be a lamp 1, a lamp fixture 2, a projector device 3, a disinfection device, or an optical wireless communication device. Lighting device light escaping from the lighting device 1200 is indicated with reference numeral 1201. The lighting device light 1201 may essentially consist of the system light 1001, and thus in a specific embodiment may be the system light 1001. In an embodiment, the light generating device 1200 may be configured to provide the system light 1001 on one or more surfaces in a room 1300. In particular, the light generating system 1000 may illuminate a wall 1307, or a floor 1305, or a ceiling 1310 in the room 1300.

[0123] The term "plurality" refers to two or more.

[0124] Those skilled in the art will understand the terms "substantially" or "essentially" and similar terms herein. The terms "substantially" or "essentially" may also include embodiments with "all", "completely", "all", etc. Therefore, in embodiments, the adjectives substantially or substantially may also be removed. Where applicable, the term "substantially" or the term "essentially" may also relate to 90% or higher, such as 95% or higher, in particular 99% or higher, even more in particular 99.5% or higher, including 100%.

[0125] The term "comprising" also includes embodiments wherein the term "comprising" means "consisting of.

[0126] The term "and / or" particularly relates to one or more of the items mentioned before and after "and / or". For example, the phrase "item 1 and / or item 2" and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may refer to "consisting of" in one embodiment, but may also refer to "including at least the specified species and optionally one or more other species" in another embodiment.

[0127] In addition, the terms first, second, third, etc. in the specification and claims are used to distinguish similar elements and not necessarily to describe a sequential or chronological order. It should be understood that the terms so used are interchangeable under appropriate circumstances, and that the embodiments of the invention described herein are capable of operation in other sequences than those described or illustrated herein.

[0128] Among other things, an apparatus, device or system may be described herein during operation. It will be clear to one skilled in the art that the present invention is not limited to methods of operation, or apparatus, devices or systems in operation.

[0129] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

[0130] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0131] The use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the specification and claims, the words "comprises," "comprising," etc. should be interpreted in an inclusive sense, rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to."

[0132] The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0133] The invention can be implemented by means of hardware comprising several distinct elements and by means of a suitably programmed computer. In an apparatus claim, or a device claim or a system claim, several means are enumerated, several of which may be embodied by the same item of hardware. The simple fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. In a further aspect, the invention (therefore) provides a software product which, when run on a computer, is capable of implementing (one or more embodiments of) the method as described herein.

[0134] The present invention also provides a control system that can control a device, apparatus or system, or can perform a method or process described herein. Still further, the present invention also provides a computer program product that, when functionally coupled to a device, apparatus or system or run on a computer included in the device, apparatus or system, controls one or more controllable elements of such a device, apparatus or system.

[0135] The present invention also applies to a device, an apparatus or a system comprising one or more of the characterizing features described in the specification and / or shown in the drawings. The present invention also relates to a method or a process comprising one or more of the characterizing features described in the specification and / or shown in the drawings.

[0136] The various aspects discussed in this patent can be combined to provide additional advantages. In addition, those skilled in the art will appreciate that the embodiments can be combined, and more than two embodiments can also be combined. In addition, some of the features can form the basis of one or more divisional applications.

Claims

1. A light generating system (1000), comprising a housing (1040) and a light generating device (100); wherein the housing (1040) comprises a light exit window (1050); wherein the light generating device (100) is configured to generate device light (101), wherein the light exit window (1050) comprises a curved optical window (400), wherein the light exit window (1050) is configured to transmit at least a portion of the device light (101) and to reflect at least a portion of the device light (101); - wherein the curved optical window (400) has a maximum height (h x )、Minimum height (h m ) and radius (r1); where 0.7≤h m / h x <1, wherein the thickness (h) of the curved optical window (400) is from the minimum height (h m ) gradually increases to the maximum height (h x ), where the minimum height (h m ) is at a maximum radius (r1) greater than the radius (r2) x ) and wherein the maximum height (h x ) is at a minimum radius (r1) smaller than the radius (r2) m ) at; wherein the curved optical window (400) comprises a polymer material (1401); and - wherein the curved optical window (400) comprises a curved polymer diffuser (400).

2. The light generating system (1000) according to claim 1, wherein the polymer material (1401) comprises one or more of PMMA and PC.

3. The light generating system (1000) according to any of the preceding claims, wherein the curved polymer diffuser (400) comprises the polymer material (1401), wherein scattering particles (1402) are embedded in the polymer material (1401).

4. The light generating system (1000) according to claim 3, wherein the scattering particles (1402) include one or more of inorganic particles and silicone particles.

5. The light generating system (1000) according to claim 4, wherein the inorganic particles include one or more of the following: TiO2 particles, BaSO4 particles and Al2O3 particles.

6. The light generating system (1000) according to any one of claims 3 to 5, wherein the scattering particles (1402) have a size (d) selected from the range of 20 nm to 4000 nm.

7. A light generating system (1000) according to any of the preceding claims, wherein the polymer material (1401) comprises one or more of PMMA and PC; wherein the curved polymer diffuser (400) comprises the polymer material (1401), wherein scattering particles (1402) are embedded in the polymer material (1401); wherein the scattering particles (1402) comprise one or more of inorganic particles and silicone particles, wherein the scattering particles (1402) have a size (d) selected from the range of 20 nm to 4000 nm.

8. The light generating system (1000) according to any one of the preceding claims, wherein the maximum height (h x ) is selected from the range of 0.9*1-3mm.

9. The light generating system (1000) according to any one of the preceding claims, wherein 0.85 ≤ h m / h x ≤0.

95.

10. The light generating system (1000) according to any of the preceding claims, wherein the radius (r1) is chosen to be at least 150 mm.

11. The light generating system (1000) according to any one of the preceding claims, wherein the maximum height (h x ) is selected from the range of 0.9*1-3mm; wherein 0.85≤h m / h x ≤0.95; and wherein the radius (r1) is selected to be at least 150 mm.

12. A light generating system (1000) according to any one of the preceding claims, wherein the curved optical window (400) has a first main surface (401) and a second main surface (402) defining the thickness (h) of the curved optical window (400), wherein when one of the first main surface (401) and the second main surface (402) is vertically irradiated with light in the visible wavelength range, at least 15% of the light is reflected and at least 50% of the light is transmitted.

13. The light generating system (1000) according to any of the preceding claims, wherein the curved optical window can have a tortuous configuration, wherein an axis of the curved optical window can include multiple curves.

14. The light generating system (1000) according to any of the preceding claims, wherein the curved optical window has a length of at least 4 meters.

15. A lighting device (1200) selected from the group of a lamp (1) and a luminaire (2), the lighting device comprising the light generating system (1000) according to any of the preceding claims 13 to 14.

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