WO2019134819A1

WO2019134819A1 - Method for manufacturing an object comprising an rf-structure

Info

Publication number: WO2019134819A1
Application number: PCT/EP2018/085384
Authority: WO
Inventors: Anteneh Alemu ABBO; Rifat Ata Mustafa Hikmet; Hongming Yang; Dave Willem VAN GOOR; Harald Josef Günther RADERMACHER
Original assignee: Signify Holding B.V.
Priority date: 2018-01-02
Filing date: 2018-12-18
Publication date: 2019-07-11

Abstract

The present invention relates to a method for manufacturing an object comprising a radio frequency, RF, structure being arranged to control a radio frequency beam. The method comprises manufacturing the object by a fused deposition modelling using a fused deposition modelling material that comprises electrically conductive particles mixed into a polymer base, wherein each electrically conductive particle has a minimum bounding box, and wherein at least one of a width, height and length of the minimum bounding box is larger than 1 µm.

Description

METHOD FOR MANUFACTURING AN OBJECT COMPRISING AN RF-STRUCTURE

FIELD OF THE INVENTION

The invention relates to method for manufacturing an object comprising a radio frequency structure being arranged to control a radio frequency beam. The invention further relates to an additive manufacturing material for additive manufacturing of an object comprising a radio frequency structure.

BACKGROUND OF THE INVENTION

Objects, such as luminaires, may be equipped with other functionalities than the primary light generation function. Radio frequency (RF) based indoor localization is one such functionality. Such an RF based indoor localization may involve using Bluetooth based beacons. Luminaires may also be equipped with connectivity functionality, such as by Bluetooth or ZigBee, for lighting control. RF based presence detection techniques are also being introduced in luminaires where conventional passive infrared (PIR) is not desired.

Problems associated with using RF based solutions relates to the radiation beam width which has impact on the performance of the intended application. For lighting control application, communication between a luminaire and controllers or between luminaires often requires a wide beam width to maximize the access range. On the other hand, localization application requires a narrow beam width to associate a beacon to a specific luminaire so that the lighting floorplan can be used for generating location and navigation services.

Although techniques are available to control RF beam widths, such techniques typically are bulky or complex and may not be suitable, for example, for luminaires for aesthetical, practical or technical reasons. Further, such techniques maybe difficult to incorporate with objects, such as a luminaire. Known techniques to handle RF

communication typically are cumbersome to manufacture and integrate with objects, such as luminaires.

Thus, there is a need for providing and manufacturing structures to control the RF beam width and to direct an RF beam to suit a desired functionality of an object, such as a luminaire, and to incorporate such structures with an object such as a luminaire. Further, there is a need for such structures to provide an overall esthetically and/or technical suitable solution together with an object, such as a luminaire.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome at least some of the above problems.

According to a first aspect, this and other objects are achieved by providing a method for manufacturing an object comprising a radio frequency, RF, structure being arranged to control a radio frequency beam. The method comprises: manufacturing the object by a fused deposition modelling process using a fused deposition modelling material, wherein the fused deposition modelling material, used during the manufacturing of the RF- structure, comprises electrically conductive particles mixed into a polymer base, wherein each electrically conductive particle has a minimum bounding box, and wherein at least one of a width, height and length of the minimum bounding box is larger than 1 pm.

Objects comprising an RF-structure allows the object to be equipped with functionalities.

Fused deposition modelling is an example of a 3D printing technology. Fused deposition modelling, also called fused filament fabrication or filament 3D printing, is one of the most commonly used forms of 3D printing. In a fused deposition modelling process, a 3D printer creates an object in a layer-by-layer manner by extruding a printable material (typically a filament of a thermoplastic material) along tool paths that are generated from a digital representation of the object. The printable material (in the context of the present invention referred to as fused deposition modelling material) is heated just beyond solidification and extruded through a nozzle of a print head of the 3D printer. The extruded printable material fuses to previously deposited material and solidifies upon a reduction in temperature. In a typical 3D printer, the printable material is deposited as a sequence of planar layers onto a substrate that defines a build plane. The position of the print head relative to the substrate is then incremented along a print axis (perpendicular to the build plane), and the process is repeated until the object is complete.

Fused deposition modelling printers are relatively fast, low cost and can be used for printing complicated three-dimensional objects. Such printers are used in printing various shapes using various 3D printable materials. The technique is also being further developed in the production of FED luminaires and lighting solutions. The fused deposition modelling process allows for efficient design of the object, and for a wide selection of shape of the object. Further, embedding, within the object, of functionalities and devices gained by the RF-structure(s) is efficiently realised. Thereby control of RF beam width may efficiently be integrated with the object.

The fused deposition modelling material comprising a polymer base with admixed electrically conductive particles lends the RF-structure suitable RF-shielding, RF- reflecting, and/or RF-directing properties. Thereby, RF beams may be controlled. The electrically conductive particles having a minimum bounding box, with at least one of a width, height and length of the minimum bounding box being larger than 1 pm, renders the RF-structure suitable for handling wavelengths in the GHz range, preferably in the 3 GHz to 30 GHz range.

The method may further comprise receiving a design of the object and the therein comprised RF-structure, wherein the act of manufacturing the object comprises manufacturing the object and the therein comprised RF-structure according to the design. Thereby, the object and the therein comprised RF-structure may efficiently be manufactured according to a desired design.

The fused deposition modelling process allows for the RF-structure to be embedded in the object. Thereby, the RF-structure may be protected by the object. Further, the RF-structure may be made invisible and the object aesthetically pleasing. The polymer base may be suitable for providing an environment for the RF-structure.

The RF-structure may comprise an RF-shield, an RF-reflector, and/or an RF- director. Thus, RF beams may be controlled to suit different purposes. Further, efficient RF control and communication related to the object is enabled. Yet further, such RF-structures provides means to control the beam width per activated functionality.

The RF-structure may further comprise an electrically driven element. The electrically driven element may be an antenna in the form of an RF sender. The electrically driven element may be arranged to be connected to RF power. The electrically driven element may function as a directional antenna. Thereby, the object may comprise an RF- antenna.

The method may further comprise adding the electrically driven element to the object, wherein the electrically driven element is a readymade structure.

The method may further comprise manufacturing the electrically driven element during the fused deposition modelling. The fused deposition modelling material used during the manufacturing of the electrically driven element may comprise admixed silver particles.

The electrically conductive particles may be present in the fused deposition modelling material at a numerical density at or above (l/(2x(l+d)))³, wherein

d is the average width, height or length of the minimum bounding box of the electrically conductive particles expressed in a unit of length, and

the numerical density is expressed as number of particles per cubic unit of length.

The highest numerical density may be within the range of 0.02 to 1000 particles per mm³. The highest numerical density may vary within the range of 0.02 to 1000 particles per mm³, as the average width, height or length of the minimum bounding box of the electrically conductive particles varies between 5 mm to 1 pm.

Such numerical density lends the RF-structure suitable properties for RF signals in the GHz range, preferably in the range of 3 GHz to 30 GHz.

An average distance between the electrically conductive particles in the RF- structure may be 1 mm or below.

The electrically conductive particles may have a dimension in the range of 1 pm to 5 mm.

Such numerical densities of the electrically conductive particles and such dimension of the electrically conductive particles lend the RF-structure suitable RF properties for RF signals in the GHz range, preferably in the range of 3 GHz to 30 GHz.

The particles may have any suitable shape. For example, the particles may have a shape selected from flat cylinders, or platelets, flakes, spherical, and cylindrical, and combinations thereof.

The electrically conductive particles may comprise a material selected from the group consisting of copper, silver, aluminum, iron, platinum and gold, and combinations thereof.

Thereby, suitable electrical conductive properties may be achieved.

The polymer base may comprise polymers such as polycarbonate, polyethylenetelapthalate, polyamide, polystyrene, polyacrylate, or polyethylene.

Such a polymer base allows for efficient fused deposition modelling and provides the object with suitable properties.

The particles may be dispersed in the polymer mixture. An object being manufactured according to the above is an object comprising a radio frequency, RF, structure that is arranged to control a radio frequency beam. An example of such an object is a luminaire.

The above object is achieved by providing a fused deposition modelling material for manufacturing, by means of fused deposition modelling, a radio frequency, RF, structure being arranged to control a radio frequency beam. The fused deposition modelling material comprises a polymer base, and electrically conductive particles having a at least one of a width, height and length of a minimum bounding box being larger than 1 pm admixed in the polymer base.

The electrically conductive particles may be present in the additive manufacturing material at a numerical density at or above (l/(2x(l+d)))³, wherein d is the average width, height or length of the minimum bounding box of the electrically conductive particles expressed in a unit of length, and the numerical density being expressed as number of particles per cubic unit of length.

The polymer base may comprise polycarbonate, polyethylenetelapthalate, polyamide, polystyrene, polyacrylate, or polyethylene. Such polymer base is suitable for additive manufacturing, while at the same time providing suitable properties to the object comprising the RF-structure.

A further scope of applicability of the present invention will become apparent from the detailed description given below. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the scope of the invention will become apparent to those skilled in the art from this detailed description.

Hence, it is to be understood that this invention is not limited to the particular component parts of the device described or steps of the methods described as such device and method may vary. It is also to be understood that the terminology used herein is for purpose of describing particular embodiments only, and is not intended to be limiting. It must be noted that, as used in the specification and the appended claim, the articles“a,”“an,”“the,” and“said” are intended to mean that there are one or more of the elements unless the context clearly dictates otherwise. Thus, for example, reference to“a unit” or“the unit” may include several devices, and the like. Furthermore, the words“comprising”,“including”,

“containing” and similar wordings does not exclude other elements or steps.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiments of the invention. The figures should not be considered limiting the invention to the specific embodiment; instead they are used for explaining and understanding the invention.

FIG 1 illustrates a method for manufacturing an object comprising an RF- structure.

FIG 2a and 2b illustrates different states of an object manufactured according to the method of FIG. 1.

FIG. 2c illustrates an antenna structure.

FIG 3 illustrates an fused deposition modelling material to be used in the method of manufacturing according to FIG. 1.

As illustrated in the figures, the sizes of layers and regions are exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of

embodiments of the present invention. Like reference numerals refer to like elements throughout.

DETAILED DESCRIPTION

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the invention to the skilled person.

With reference to figure 1 a method 1 for manufacturing an object comprising an RF-structure will now be described. The RF, structure is a structure arranged to control a radio frequency beam. The method comprises manufacturing 2 the object by a fused deposition modelling process. The RF-structure is also manufactured during the fused deposition modelling process. The RF-structure is manufactured using a fused deposition modelling material comprising electrically conductive particles mixed into a polymer base. The electrically conductive particles have a minimum bounding box, wherein at least one of a width, height and length of the minimum bounding box being larger than 1 pm.

The method 1 may further comprise receiving 4 a design of the object and the therein comprised RF-structure, wherein the act of manufacturing 2 the object comprises manufacturing the object and the therein comprised RF-structure according to the design.

With methods described herein, an RF-structure such as an RF shield, an RF director and/or an RF reflector, or combinations thereof, may be integrated in an object by an additive manufacturing process. The object maybe a luminaire. The RF-structure may be manufactured in the form of a plate, a curved surface such a hollow hemisphere, wire stripes or a mesh having suitable shape and dimensions. For example, by means of fused deposition modelling an RF-beam shaping structure in the form of RF shield, RF director or RF reflector a desired beam shape may be generated during use of the object. During the fused deposition modelling also an electrically driven element, such as an RF-antenna, may be manufactured. The electrically driven element and the beam shaping structure may be manufactured in subsequent steps, or otherwise suitably positioned within the object.

It has been realized that, at high frequencies, there is no need for the RF structure to be manufactured in the form of solid metal structures in order to function as desired but conductive particles admixed in a polymer base, wherein the particle sizes and spacing meet the wavelength requirement, may efficiently be used as described herein. For example, RF wavelength in the frequency range of GHz, preferably 3 GHz to 30 GHz requires that the distance between the particles is less than lmm, and the particles need to have dimensions larger than 1 pm in at least one of a width, height and length of the minimum bounding box of the RF structure to function as desired. The electrically conductive particles may have a width, height or length of the minimum bounding box in the range of 1 pm to 5 mm.

Suitably, the electrically conductive particles comprise, or essentially consists of, metal selected from copper, silver, aluminum, iron, platinum and gold, or combinations thereof.

As an example, during the production of a luminaire, a polymer base with admixed electrically conductive particles may be used to print RF-structures in various areas to produce, for example, multiple antenna orientations and/or one or more of an RF shield, an RF director and/or an RF reflector. By choosing the shape and direction of the RF-structures radiation direction and shape of the beam can be adjusted. The RF-structure may comprise a structure which may be described as a mesh, grid or by stripes or wires.

With reference to figure 2a and 2b, schematic manufacturing of an object 6 is illustrated. In the manufacturing, multiple antenna structures 8a-c are manufactured by addition of a polymer base with admixed electrically conductive particles as illustrated in figure 2a. Further, suitable electronics 12 may be integrated with the object 6, which electronics 12 may comprise, for example, an antenna selection switch.

As illustrated in figure 2b, one or more shielding structures lOa, lOb with suitable geometric shapes to desirably match the RF beam pattern maybe added to the object 6. The shielding structure may be any one of an RF shield, an RF director and/or an RF reflector. The shielding structures 10a, 1 Ob are manufactured by addition of a polymer base with admixed electrically conductive particles. The shielding structures lOa, lOb may, for example, comprise wire or mesh structures. The shielding structures lOa, lOb may reflect RF waves to desired directions and/or block signals from undesired directions. The shielding structures lOa, lOb may be manufactured using fused deposition modelling directly on the object 6. Alternatively, or in combination, the shielding structures lOa, lOb may be separately manufactured and thereafter attached to the object 6.

The object 6, as illustrated in figure 2b may handle and transfer RF beams to the antenna structures 8a, 8b, 8c by means of the shielding structures lOa, lOb. In this illustrated example, the design allows shielding structure 10a to direct a constrained RF beam towards antenna structure 8a for the purpose of RF presence sensing. Further, shielding structure 10b direct a narrow RF beam towards antenna structure 8b for the purpose of localization beacon. Antenna structure 8c is not associated with a particular shielding structure, and antenna structure 8c may suitably be applied for receiving a wide RF beam for the purpose of communication. Although not illustrated, antenna structures 8a-c and RF electronics may be suitably connected by, for example, wires or other suitable type of means for connection.

Figure 2c illustrates schematically an antenna structure 8a-c with corresponding impedance matching network 14 comprising ground 16.

During the manufacturing, the antenna structures 8a-c and corresponding impedance matching network are designed with respect to properties and type of material used in the printing process and of the object, such as, for example, dielectric coefficient of the object 6. With reference to figure 3, a fused deposition modelling material 30 for manufacturing of an RF-structure by means of fused deposition modelling is schematically illustrated. The fused deposition modelling material 30 comprises a polymer base 32, and electrically conductive particles 34. The electrically conductive particles having a at least one of a width, height and length of a minimum bounding box being larger than 1 pm. The electrically conductive particles are admixed in the polymer base 32. ln this example, the electrically conductive particles 16 are illustrated as being essentially spherical with a diameter being larger than 1 pm. However, the electrically conductive particles 16 may have other shapes. For example, the particles may have a shape selected from flat cylinders, platelets, flakes, spherical, and cylindrical, and combinations thereof.

The electrically conductive particles 16 may comprise or essentially consist of a material selected from the group consisting of copper, silver, aluminum, iron, platinum and gold, and combinations thereof.

The polymer base 14 may comprise polycarbonate, polyethylenetelapthalate, polyamide, polystyrene, polyacrylate, or polyethylene.

RF beam shaping or shielding enabled with embodiments described herein, may suitable and in addition be applied, for example, in situations where shielding of sensitive electronic subsystem from external interference is desired, or to block locally generated electro -magnetic interference.

The electrically driven element which is powered with RF signal can be a ready to use element such as an electrically conductive wire or printed electrically conductive lines on a substrate. This ready to use element may be inserted into the RF structure. The electrically driven element may also be manufactured by means of fused deposition modelling or by (dispensing) using a conductive material such as silver suspended in a solution. Preferably the conductivity of the driven element is above lxlO ⁷ W.hi.

Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims ln the claims, the word“comprising” does not exclude other elements or steps, and the indefinite article“a” or“an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

Claims

CLA1MS:

1. A method for manufacturing an object comprising a radio frequency, RF, structure being arranged to control a radio frequency beam, the method comprising:

manufacturing the object by means of fused deposition modelling using a fused deposition modelling material, wherein the fused deposition modelling material, used during the manufacturing of the RF-structure, comprises electrically conductive particles mixed into a polymer base, wherein each electrically conductive particle has a minimum bounding box, and wherein at least one of a width, height and length of the minimum bounding box is larger than 1 pm.

2. The method according to claim 1, further comprising

receiving a design of the object and the therein comprised RF-structure, wherein the act of manufacturing the object comprises manufacturing the object and the therein comprised RF-structure according to the design.

3. The method according to claim 1 or 2, wherein the RF-structure is embedded in the object.

4. The method according to anyone of the previous claims, wherein the RF- structure comprises an RF-shield, an RF-reflector, and/or an RF-director.

5. The method according to anyone of the previous claims 1 to 4, wherein the RF-structure further comprises an electrically driven element.

6. The method according to claim 5, further comprising adding the electrically driven element to the object, wherein the electrically driven element is a readymade structure.

7. The method according to claim 5, further comprising manufacturing the electrically driven element during the fused deposition modelling.

8. The method according to any one of claims 1-4, wherein the electrically conductive particles are present in the fused deposition modelling material, used during the manufacturing of the RF-structure, at a numerical density at or above (l/(2x(l+d)))³, wherein d is an average width, height or length of the minimum bounding box of the electrically conductive particles expressed in a unit of length,

the numerical density being expressed as number of particles per cubic unit of length.

9. The method according to anyone of claims 1-8, wherein the electrically conductive particles have a width, height or length of the minimum bounding box in the range of 1 pm to 5 mm.

10. The method according to anyone of claims 1-9, wherein the electrically conductive particles comprise a material selected from the group consisting of copper, silver, aluminum, iron, platinum and gold, and combinations thereof.