WO2021037815A1

WO2021037815A1 - A layout generation system, corresponding method and computer program for generating a layout of a printed circuit board

Info

Publication number: WO2021037815A1
Application number: PCT/EP2020/073665
Authority: WO
Inventors: Albertus Adrianus SMITS; Olena Viktorivna IVANOVA
Original assignee: Signify Holding B.V.
Priority date: 2019-08-28
Filing date: 2020-08-24
Publication date: 2021-03-04

Abstract

The present invention relates to a system, corresponding method and computer program for generating a layout of a printed circuit board, PCB (800, 1000), and to an area light source comprising the generated layout. The system (1) comprises an optical requirements providing unit (10), a building blocks providing unit (20), a unit (30) for providing an electrical layout (220, 320) of the PCB (800, 1000), the electrical layout (220, 320) comprising a linear connection of building blocks (22, 24, 26, 820, 920) provided by the building blocks providing unit (20) in order to form a strip-like electrical layout (220, 320), a unit (40) for positioning the light elements of the building blocks of the electrical layout (220, 320) along a not-self-intersecting curve on the surface of the PCB (800, 1000) under consideration of the optical requirements, a unit (50) for providing a printed circuit board of a particular shape, and a unit (60) to determine the not-self- intersecting curve (510, 530, 540, 550, 560, 610, 620, 630, 640, 650, 660, 810, 1010) of a predefined width so as to fill the shape of the printed circuit board (800, 1000).

Description

A layout generation system, corresponding method and computer program for generating a layout of a printed circuit board

FIELD OF THE INVENTION

The present invention relates to a layout generation system, a corresponding method and a corresponding computer program for generating a layout of a printed circuit board. The present invention further relates to an area light source such as a ceiling luminaire generated using the system or method according to the invention.

The present invention finds particular application in the field of lighting devices such as luminaires, however, the present invention is not limited to these applications.

BACKGROUND OF THE INVENTION

Devices using area light sources are known and used, for instance, as ceiling luminaires. Such devices often intend to generate a substantially uniform or desired luminance across the whole area of the area light source.

In the development of such devices, it is known to position light elements, such as light emitting diodes (LEDs), on a printed circuit board (PCB) in order to fulfil optical requirements of a desired luminance pattern.

In particular, in multichannel layouts, e.g. for multicolor or tunable white luminaires, the correct electrical connection of light elements positioned according to the known procedures can be complicated and involve the use of extra components like jumpers to cross other traces.

It is further challenging to, at the same time, ensure good color mixing or flux homogeneity and to fulfil the cooling requirements of the light elements, which can be requirements in conflict with the electrical connection.

SUMMARY OF THE INVENTION

It can therefore be regarded an object of the present invention to improve the generation of a layout of a PCB, in particular regarding the need to introduce additional components. According to a first aspect, a layout generation system configured to generate a layout of a PCB is provided. The layout generation system comprises: an optical requirements providing unit configured to provide optical requirements of a luminance pattern to be emitted by the PCB, a building blocks providing unit configured to provide at least one type of building blocks, the at least one type of building blocks comprising electrical connections to at least one adjacent building block and at least one light element and, an electrical layout generating unit configured to provide an electrical layout of the PCB, the electrical layout comprising a linear connection of building blocks provided by the building blocks providing unit in order to form a strip-like electrical layout, a light elements positioning unit configured to position the light elements of the building blocks of the electrical layout provided by the electrical layout generating unit along a not-self-intersecting curve on the surface of the PCB under consideration of the optical requirements.

Since the building blocks providing unit provides building blocks, which can be connected in a linear manner to create a strip-like electrical layout, this strip-like electrical layout can be mapped onto the curve on the surface of the PCB while ensuring that the light elements be electrically connected in a correct way, while the need for extra components such as jumpers can be reduced or avoided.

It is key for the present invention to recognize that a curve on the surface of the PCB, which is not-self-intersecting, can be used to be mapped with a strip-like electrical layout formed of building blocks. By mapping the linear, strip-like electrical layout with the curve, the electrical connections between the building blocks and thus the light elements can be preserved. At the same time, the step of mapping the strip-like electrical layout to the curve can guarantee that the electrical connections on the PCB are correct.

The optical requirements preferentially include color requirements, e.g. multicolor or tunable white requirements, and can include further requirements of the desired luminance pattern, for instance the size and/or shape thereof. Further, the optical requirements can include diffusion or other optical properties and the like.

In a preferred embodiment, the light elements positioning unit is configured to optimize the positions of the building blocks of the electrical layout along the not-self- intersecting curve on the basis of at least one of color mixing and output flux homogeneity.

In the procedures known from the prior art as described above, the light elements are positioned on the PCB to comply with the requirements of the luminance pattern and with the optical requirements. Based on the constraint of the positions of the light elements, the electrical connections were previously designed, thereby causing the difficulties described above.

According to the present invention, the order of steps is inverted with respect to the known procedures.

The present invention first provides the strip-like electrical layout, which is mapped onto the not-self-intersecting curve. The electrical layout can thus be regarded fixed and poses a constraint for the positions of the light elements. The positions of the light elements can thus advantageously be defined along the not-self-intersecting curve to comply with the optical requirements without implications on the electrical layout.

Expressed differently, according to the present invention the positions of the light elements are defined in a second steps, after the strip-like electrical layout is defined in a first step. The positions are then advantageously defined under consideration of a linear constraint, i.e. the positions are preferably restricted to be along the not-self-intersecting curve.

In this embodiment, due to the degree of freedom in positioning the light elements along the curve, the positions of the light elements can ensure good color mixing and flux homogeneity as desired or as imposed by the optical requirements. Preferentially, the light elements positioning unit implements an optimization algorithm for determining the positions of the light elements along the curve.

In a preferred embodiment, the building blocks providing unit is configured to dimension the electrical connections under consideration of a cooling requirement of the at least one light element.

The electrical connections are suitable to dissipate heat from the light elements. Sufficient dimensions of the electrical connections can thus guarantee enough heat dissipation to comply with the cooling requirements of the light elements.

In a preferred embodiment, the electrical connections comprise copper.

Copper is a particularly efficient heat conductor.

In a preferred embodiment, the building blocks comprise at least one of a strip start building block, a light elements building block, a resistor block, and a strip end building block. Thus, the complete electrical layout can be composed of linearly connected, adjacent building blocks.

In a preferred embodiment, the light elements building block comprises three light elements of different color. Thus, the building blocks allow a multichannel layout of the PCB. In other embodiments additionally or alternatively building blocks with one light element, two light elements or more than three light elements are provided.

In a preferred embodiment, the layout generation system further comprises a shape providing unit configured to provide the printed circuit board of a particular shape, a filling unit configured to determine the not-self-intersecting curve of a predetermined width so as to fill the shape of the printed circuit board.

The curve, which can also in some embodiments be referred to as a spiral, with which the shape of the PCB is filled, accounts for a continuous and non-intersecting path which covers substantially the entire PCB surface.

Filling the PCB surface can also be expressed as drawing a continuous and not self intersecting space filling free form line. A plurality of forms of filling the shape of the PCB are known.

In one embodiment, an algorithm as described in WO 2017/181497 A1 can be advantageously employed. Using this algorithm, a continuous path filling a singly connected two-dimensional region, such as the shape of the PCB, can be found. It is preferred that the curve has few turns and is composed of long, low curvature paths, which is beneficial for the generation of the layout of the PCB, in particular in respect to the mapping of the electrical layout.

The width of the curve is preferentially chosen in accordance with the requirements of the building blocks, i.e. the width of the curve corresponds at least to a width of the building blocks.

For instance, in one example a luminance pattern which requires a low spatial density of light elements allows for a larger width of the curve, i.e. to a pattern in which adjacent turns of the curve have a larger distance from each other. In the opposite case, in case the rather high light element density is required for the desired luminance pattern, it is preferred to provide the curve with the lower width, such that adjacent turns of the curve are closer together.

It should be noted that filling the shape of the PCB does not necessarily require a complete coverage of the shape by the curve. Instead, the substantially complete coverage, as is the result by the above indicated algorithm, for instance, is considered a curve filling the PCB. In a preferred embodiment, the predefined width of the curve corresponds at least to a width of the strip-like electrical layout. Thus, colliding positions or an intersecting of light elements of different turns of the curve can be avoided.

In a preferred embodiment, the electrical layout generating unit is configured to generate at least two separate electrical layouts of the printed circuit board, wherein each of the at least two separate electrical layouts is configured to independently create the desired luminance pattern, wherein the light elements positioning unit is configured to position the light elements of the building blocks of each of the electrical layouts along the not-self- intersecting curve.

In a preferred embodiment, the layout generation system further comprises a dividing unit configured to divide the printed circuit board into a number of sub-boards, the number of sub-boards corresponding to the number of separate electrical layouts, wherein each of the sub-boards comprises all light elements of one of the separate electrical layouts.

Since the layout generation system creates at least two sub-boards which independently serve to create the desired luminance pattern, the utilization of the PCB is at least doubled. Expressed differently, since two independently operating sub-boards, each suitable for illuminating with the desired luminance pattern, are obtained, the PCB area of each area light source can significantly be reduced.

In a preferred embodiment, the dividing unit is configured to divide the printed circuit board using a meandering cut along the curve such that the cut intersects a center of the curve between two light elements of different separate electrical layouts.

Since in this embodiment the cut intersects the center of the curve between two light elements of different separate electrical layouts, two adjacent building blocks or light elements along the curve will be located at opposite sides with respect to the cut, i.e. will be positioned at different sub-boards, respectively. The meandering cut can in principle have any shape, while straight lines are in one embodiment preferred over curved shapes due to the simpler implementation in practice. Thus, preferentially, a meandering cut is executed in the form of a square saw tooth shape along the curve. The cut is of course not limited to this shape and other shapes are contemplated.

In a preferred embodiment, the light elements positioning unit is configured to define the positions of the light elements along a center of the curve. Using the center of the curve, a minimum distance between light elements of adjacent turns of the curve can be preserved. A center of the curve is in this embodiment to be understood as a center in the width wise direction of the curve. Thus, two light elements being defined at adjacent turns of the curve are positioned with at least a width of the curve apart. Further, the separation of the PCB into sub-boards gets facilitated.

In a preferred embodiment, the light elements positioning unit is configured to define non-intersecting positions of the light elements.

In a preferred embodiment, the light elements positioning unit is configured to cyclically alternate light elements of each separate electrical layout along the curve.

In a preferred embodiment the dividing unit is configured to divide the printed circuit board such that each of the obtained sub-boards provides a connected surface.

Since each of the obtained sub-boards provides a connected surface, the luminance pattern generated by each of separate electrical layouts is located on a single sub board. Thus, no electrical connection between two or more sub-boards is necessary in order to achieve the desired luminance pattern. To the contrary, each sub-boards providing the connected surface achieves the desired luminance pattern by itself.

In a preferred embodiment at least one of the sub-boards is a multichannel printed circuit board. Thus, the at least one sub-board can achieve a multichannel luminance by itself. Additionally, or alternatively, at least two of the sub-boards can be complementary sub-boards, such that one two different channels are implemented in the at least two sub boards. Thus, a multichannel layout can be achieved by stacking the at least two sub-boards together. Thus, the flexibility of the obtained luminance device is increased.

Since each of the sub-boards becomes flexible after the cut due to its shape, a 3D or volumetric light source can be achieved by flexing the sub-board in a direction normal to or perpendicular to the original plane of the PCB.

In a preferred embodiment, the optical requirements providing unit is configured to provide optical requirements on the basis of a substantially uniform area luminance pattern as the luminance pattern. Of course the luminance pattern is not limited to uniform, and also color mixes or temporally varying luminance patterns are contemplated.

In a preferred embodiment, the light elements comprise at least one of warm white light emitting diodes, LEDs, cold white LEDs and colored LEDs.

According to a second aspect, a layout generation method to generate a layout of a printed circuit board is provided, the layout generation method comprising: an optical requirements providing step of providing optical requirements of a luminance pattern to be emitted by the printed circuit board, a building blocks providing step of providing at least one type of building blocks, the at least one type of building blocks comprising electrical connections to at least one adjacent building block and at least one light element and, an electrical layout generating step of providing an electrical layout of the printed circuit board, the electrical layout comprising a linear connection of building blocks provided by the building blocks providing unit in order to form a strip-like electrical layout, a light elements positioning step of positioning the light elements of the building blocks of the electrical layout provided by the electrical layout generating unit along a not-self-intersecting curve on the surface of the printed circuit board under consideration of the optical requirements.

The layout generation method according to this aspect can achieve the same advantages as the layout generation system according to the first aspect, and can further beneficially be combined with the preferred embodiments described with respect to the first aspect.

According to a third aspect, an area light source comprising a printed circuit board generated by carrying out the layout generation method according to the second aspect using the layout generation system according to first aspect is provided.

According to a fourth aspect, a computer program for generating a printed circuit board is provided, the computer program comprising program code means for causing a layout generation system according to the first aspect to carry out the layout generation method according to the second aspect, when the computer program is run on the layout generation system.

It shall be understood that the layout generation system of claim 1, the layout generation method of claim 13, the area lights source of claim 14, and the computer program of claim 15, have similar and/or identical preferred embodiments, in particular, as defined in the dependent claims.

It shall be understood that a preferred embodiment of the present invention can also be any combination of the dependent claims or above embodiments with the respective independent claim.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS In the following drawings: Fig. 1 schematically and exemplarily illustrates a layout generation system,

Fig. 2 schematically and exemplarily illustrates an example of building blocks, Fig. 3 schematically and exemplarily illustrates a further example of building blocks,

Fig. 4 schematically and exemplarily illustrates a further example of building blocks,

Fig. 5 schematically and exemplarily illustrates examples of curves for filling a surface,

Fig. 6 schematically and exemplarily illustrates examples of curves for filling a surface,

Fig. 7 schematically and exemplarily illustrates a PCB,

Fig. 8 schematically and exemplarily illustrates a PCB according to the present invention,

Fig. 9 schematically and exemplarily illustrates a PCB according to the present invention,

Fig. 10 schematically and exemplarily illustrates an example of dividing a

PCB,

Fig. 11 schematically and exemplarily illustrates a further example of dividing a PCB, Fig. 12 schematically and exemplarily illustrates a further example of dividing a PCB, Fig. 13 schematically and exemplarily illustrates a further example of dividing a PCB, Fig. 14 schematically and exemplarily illustrates a further example of dividing a PCB, Fig. 15 schematically and exemplarily illustrates a further example of dividing a PCB, Fig. 16 schematically and exemplarily illustrates a further example of dividing a PCB and Fig. 17 schematically and exemplarily illustrates a flowchart of a method.

DETAILED DESCRIPTION OF EMBODIMENTS

Fig. 1 shows schematically and exemplarily a layout generation system 1 configured to generate a layout of a printed circuit board (PCB). Layout generation system 1 comprises an optical requirements providing unit 10, a building blocks providing unit 20, an electrical layout generating unit 30, a light elements positioning unit 40, a shape providing unit 50, a filling unit 60 and a dividing unit 70.

The optical requirements providing unit 10 is configured to provide optical requirements of a luminance pattern to be emitted by the PCB. The optical requirements include color requirements, e.g. multicolor or tunable white requirements, and can include further requirements of the desired luminance pattern, for instance the size and/or shape thereof. Further, the optical requirements can include diffusion or other optical properties and the like.

Further, the building blocks providing unit 20 provides at least one type of building blocks. The at least one type of building blocks will be detailed with regard to figures 2 to 4 below.

Further, an electrical layout generating unit 30 is provided, which is configured to provide an electrical layout of the PCB based on the building blocks provided by the building blocks providing unit 20, in order to form a strip-like electrical layout.

Fig. 2 schematically and exemplarily illustrates a first example of building blocks 22 obtained from a single channel electrical layout 200. A parallel circuit 210 of a plurality of lighting elements 212 can equally be expressed by a linear, strip-like connection of building blocks 22, as shown in a strip-like electrical layout 220 in the lower part of Fig. 2.

In this example, electrical connections 214 and 216, which were arranged at opposite ends of the electric layout of parallel circuit 210, are provided at the same side, e.g. the beginning, of strip-like electrical layout 220 as shown on the left side of Fig. 2.

Each building block 22 comprises a light element 212, in this example a LED, as well as a supply and a return line 218, 219. Thus, each building block 22 comprises three connections to the preceding building block and three connections to a subsequent building block, for instance another building block 22. Accordingly, a linear connection of building blocks 22 is straightforward.

In essence, the single channel board with three parallel strings as illustrated in the electric layout of parallel circuit 210 is converted to a strip-like electrical layout 220 using building blocks 22. It should be noted that building blocks 22 can automatically be determined based on the electric layout of parallel circuit 210 or can be provided by a product architect, for instance. Fig. 3 schematically and exemplarily illustrates the creation of a strip-like electrical layout 320 from a multichannel layout 300. In this example, classical electrical layout 310 comprises two parallel lines of three parallel lines of different light elements 312,

314, 316 each. In this example, red light elements 312 are parallel arranged with green light elements 314 and blue light elements 316.

A building block 24 comprises accordingly three light elements 312, 314 and 316, such that each color is represented once in building block 24. Additionally, each building block 24 comprises three supply lines 318 and needs only one return line 319. Thus, building block 24 can allow the creation of a strip-like electrical layout 320 for a multichannel board with seven connections on both sides to adjacent building blocks.

Fig. 4 schematically and exemplarily illustrates building blocks 25, 26, 27, 28, 29 for an electrical layout of one-sided three channel strips, which are connectable in parallel.

Building block 25 is a strip start building block. Building block 26 is the light elements building block comprising a red light element 312 the green light element 314 and a blue light element 316 together with a plurality of supply lines 318 and return lines 319. Building block 27 is a resistor building block, in this example, a green light element resistor block. Building blocks 28 and 29 are two alternatives of a strip and building block. Building blocks 25 and 29 as well as 27 comprise resistors 250 and jumpers 290, for instance.

An example of a layout of two boards connected in parallel comprises, in order, building block 25, 26, 27 with red resistor, 26, 27 with green resistor, 26, 27 with blue resistor, 26, 26, 26, 28, 29 and in parallel thereto 26, 27 with red resistor, 26, 27 with green resistor, 26, 27 with blue resistor, 26, 26, 26, 28.

Building blocks 22, 24, 25, 26, 27, 28 and 29 are of course examples of suitable building blocks, wherein the possibility of defining additional building blocks is of course contemplated and readily known for the skilled person.

Returning to Fig. 1, layout generation system one further comprises a light elements positioning unit 40, which is configured to position the light elements of the electrical layout, such as electric layout 320 or 220, on the PCB. For this purpose, the strip-like electrical layout is mapped onto the PCB. Details of the operation of light elements positioning unit 40 will be described below.

Layout generation system 1 further comprises a shape providing unit 50 configured to provide the printed circuit board of a particular shape, and a filling unit 60, which is configured to determine a not-self intersecting curve of the predetermined width so as to fill that shape of the PCB. Preferentially, an algorithm as disclosed in W02017/181497 A1 is used for filling an area of the PCB with a curve of a certain width. The width of the curve preferentially corresponds to at least a width of the building blocks as defined by building blocks providing unit 20. Thus, a mapping between the strip-like electrical layout and the not-self intersecting curve as provided by filling unit 60 is easily achieved.

Various examples of curves for filling a surface are illustrated with reference to Figs. 5 and 6. Fig. 5 illustrates a zigzag filling 510, a Hilbert filling 530, a spiral filling 540, a first Fermat spiral 550 and a second Fermat spiral 560. The first and second Fermat spiral 550 and 560 differ in the beginning and end points, which are on opposite edges in the first Fermat spiral 550 and in the same edge for the second Fermat spiral 560.

Fig. 6 schematically and exemplarily illustrates the result of the above indicated algorithm for arbitrary shaped PCBs. A curve 610 illustrates the filling for a dancer, just like curves 620 and 630. A curve 640 illustrates the filling of a crane, a curve 650 of a butterfly and a curve 660 of a hand. Of course the shape is not limited to the illustrated shapes and arbitrary shapes are feasible. Compared to, in particular, the zigzag filling 510, curves 610 to 660 have fewer turns and are composed mostly of long, low curvature paths, which is highly beneficial for electrical layout.

Returning again to Fig. 1, layout generation system 1 comprises, as indicated above, light elements positioning unit 40, which is configured to position the light elements of the building blocks of the electric layout along the curve. Thus, the light elements of the building blocks, such as building blocks 22, 24, or 26 can be shifted along the curve, such as curve 610, 620, 630, to achieve appropriate color mixing and luminance homogeneity. Preferentially, and optimization algorithm is employed by light elements positioning unit 40 for this purpose.

Fig. 7 schematically and exemplarily illustrates the layout of a PCB 700, which does not employ layout generation system 1 according to the present invention. PCB 700 comprises in total 24 blocks of three light elements, namely one cool white, one RGB and one warm white, each. Three strings of eight blocks of three light emitting elements that are connected in series, are connected in parallel with a return track placed on the top surface of PCB 700.

Figs. 8 and 9 schematically and exemplarily illustrates a PCB 800, which has been generated using layout generation system 1 according to the present invention. A curve 810, in this example a spiral, has been drawn on PCB 800 and building blocks 820 are positioned in series along curve 810. Building blocks 820 can, for instance, correspond to building blocks 22, 24 or 26 as described above. Compared to the layout of PCB 700 as shown in Fig. 7, the luminance uniformity across PCB 800 is improved, as can be defined as the number of three light element blocks, compared to the original layout. In Fig. 9, building blocks 920 are used instead of building blocks 820 as illustrated in Fig. 8. In this example, the orientation of light elements differs between building blocks 820 and 920, wherein the arrangement of the three light elements is radially in building blocks 920 and circumferentially building blocks 820.

The invention allows the creation of a multichannel board as is used for multicolor or tunable white luminaires which fulfill the generally conflicting requirements of positioning light elements for good color mixing and flux homogeneity, the free area requirement for cooling the light elements and the correct electrical connection of the light elements. Further, layout generation system 1 as described in this invention works for all kinds of board shapes, like round, rectangular and so on.

Further, layout generation system 1 is suitable for both single-channel and multichannel boards. The algorithm of the present invention is different from the known approaches, since first building blocks are identified, which are formed by the component and the electrical connections between the next component. Examples of building blocks are building blocks 22, 24 and 26 as well as 820 and 920. Building blocks should contain enough electric connection material, such as copper, to achieve sufficient cooling for the light elements. With these building blocks, a strip-like board fulfilling the electrical requirements and facilitating electrical connections can be created.

The strip-like board is then mapped on the board to guarantee that the electrical connection is correct. In such case, preferentially no jumper 290 is needed. As a next step, building blocks can be shifted along the curve to which the strip-like layout is mapped to meet the optical requirements, for instance for color mixing and flux homogeneity.

Returning to Fig. 1, layout generation system 1 further comprises a dividing unit 70 configured to divide the PCB into a number of sub-boards. The number of sub-boards corresponds to the number of separate electrical layouts generated by the electrical layout generating unit 30 in some embodiments. Each of the at least two separate electrical layouts is configured to independently create the desired luminance pattern.

Dividing unit 70 improves the utilization of the available PCB size or, expressed differently, reduces the PCB size necessary for arbitrary shaped area luminance sources. It is known that some applications, such as the ceiling luminaires, require area light sources of a large area. These can have a large PCB area with very sparsely distributed light elements. Dividing unit 70 can thus help in reducing the PCB size without significant impact on the board performance.

With the method as outlined below, an arbitrary shape PCB can be divided into a plurality of sub boards in such a way that each of the resulting sub boards can produce uniform or desired luminance, i.e. fulfill the optical requirements.

The sub-boards can further be stacked back together, if needed. This allows for the flexibility of creating boards comprising a plurality of sub-boards with double flux or, for instance, tunable white boards or tunable color boards.

For example, to create the tunable white board, the original PCB is cut into two pieces, then, on one of those boards, warm white light elements are placed and on the other board cool white light elements are placed. These boards can then be used either alone to provide a cold white or a warm white source separately, or they can be stacked back together to create a universal white source.

Additionally, after dividing the board using the method as outlined below, each of the sub boards becomes flexible in the direction perpendicular to the surface of the original PCB. This flexibility can be used to create not only 2-D area light sources, but also 3-D volumetric light sources by flexing the board in a direction perpendicular to the original PCB plane.

Fig. 10 illustrates PCB 1000 on which a curve 1010 has been determined, for instance by filling unit 60. Along curve 1010, light elements 1020 and 1030 are alternately provided. Light elements 1020 and 1030 can also be arbitrary building blocks comprising one or more light elements, such as building blocks 22, 24 or 26 as described above.

A cut 1012 is drawn along the curve 1010 to separate PCB 1000 into two sub boards 1100, 1200, wherein each of the light element 1020 belonging to one of at least two separate electrical layouts is arranged on one side of cut 1012 and each of light elements 1030 belonging to the other of the two separate electrical layouts as illustrated in Fig. 10 is on the other side of cut 1012.

Thus, two independently operating sub boards 1100, 1200 are obtained. Light elements 1020 and light elements 1030 do not intersect and satisfy the thermal requirements, i.e. have a minimum distance between them. For the arrangement of light elements 1020 in 1030 along curve 1010, and optimization algorithm can be employed.

Cut 1012 is shown as a saw tooth shaped meandering cut however, also other shapes of cut 1012 are of course contemplated. Fig. 11 schematically and exemplarily illustrates the subdivision into three sub boards 1100, 1200, 1300. Sub-board 1100 comprises all light elements 1040, sub-board 1200 comprises all light elements 1030 and sub-board 1300 comprises all light elements 1020. In this example is, two cuts 1012 are to be provided.

Fig. 12 schematically and exemplarily illustrates a further division of PCB 1000 into four sub boards 1100, 1200, 1300, 1400 comprising the complete set of light elements 1020, 1030, 1040 or 1050, respectively.

It should be emphasized that the division by dividing unit 70 is not limited to two, three or four sub-boards and any arbitrary division of PCB 1000 is possible, as long as the width of the resulting sub boards is thick enough in order to fulfill stability and electrical connection requirements.

Figs. 13 to 16 schematically and exemplarily illustrate the division of a PCB 1000 of arbitrary shape into two sub-boards 1100, 1200. Different types of Fermat spirals are used for filling PCB 1000 with a continuous and not-self intersecting curve of a fixed width.

Fig. 13 and 14 are similar to each other, wherein curve 1010 starts and ends at opposite edges in Fig. 13 and starts and ends at the same edge in Fig. 14.

Fig. 15 illustrates schematically and exemplarily a circular board, while Fig.

16 illustrates the cutting into two sub boards for an egg-shaped PCB 1000.

Fig. 17 schematically and exemplarily illustrates a flow diagram of a method 100 for generating a layout of the PCB. The method comprises a step 110 of providing optical requirements of a luminance pattern to be emitted by the PCB.

Further, method 100 comprises a step 120 of providing at least one type of building blocks, such as building blocks 22, 24, 26, wherein the at least one type of building blocks comprises electrical connections to at least one adjacent building block and at least one light element, such as the LED.

Further, in a step 130, an electrical layout of the PCB is provided. The electrical layout comprises a linear connection of building blocks, which are connected in order to form a strip-like electrical layout.

Finally, in a step 140, light elements of the building blocks of the electrical layout are positioned along a not-self intersecting curve on the surface of the PCB under consideration of the optical requirements. To this end, the strip-like electrical layout is mapped onto the curve, wherein the light elements are preferentially shifted along the not-self intersecting curve in order to optimize their position in terms of luminance pattern. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

A single unit or device may fulfill the functions of several items recited in the claims. The mere 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.

Procedures like the provision of optical requirements, the provision of building blocks, the provision of the electrical layout, the filling of the shape of the PCB, the positioning of the light elements, the division of the PCT into sub-boards, et cetera, performed by one or several units or devices can be performed by any other number of units or devices. These procedures, particularly the filling of the PCB with a not-self-intersecting curve of a predefined width and the defining of the positions of the light elements can be implemented as program code means of a computer program and/or as dedicated hardware.

A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium, supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

Any reference signs in the claims should not be construed as limiting the scope.

The present invention thus relates to a system, corresponding method and computer program for generating a layout of a PCB and to an area light source comprising the generated layout. The system comprises an optical requirements providing unit, a building blocks providing unit, a unit for providing an electrical layout of the PCB, the electrical layout comprising a linear connection of building blocks provided by the building blocks providing unit in order to form a strip-like electrical layout and a unit for positioning the light elements of the building blocks of the electrical layout along a not-self-intersecting curve on the surface of the PCB under consideration of the optical requirements. The generation of a layout of a PCB is thereby improved.

Claims

CLAIMS:

1. A layout generation system configured to generate a layout of a printed circuit board (800, 1000), the layout generation system (1) comprising: an optical requirements providing unit (10) configured to provide optical requirements of a luminance pattern to be emitted by the printed circuit board (800, 1000), a building blocks providing unit (20) configured to provide at least one type of building blocks (22, 24, 26, 820, 920), the at least one type of building blocks (22, 24, 26, 820, 920) comprising electrical connections to at least one adjacent building block (22, 24,

25, 26, 27, 28, 29, 820, 920) and at least one light element (212, 312,314, 316), an electrical layout generating unit (30) configured to provide an electrical layout (220, 320) of the printed circuit board (800, 1000), the electrical layout (220, 320) comprising a linear connection of building blocks (22, 24, 26, 820, 920) provided by the building blocks providing unit (20) in order to form a strip-like electrical layout (220, 320), a light elements positioning unit (40) configured to position the light elements (212, 312,314, 316) of the building blocks (22, 24, 26, 820, 920) of the electrical layout (220, 320) provided by the electrical layout generating unit (30) along a not-self-intersecting curve on the surface of the printed circuit board (800, 1000) under consideration of the optical requirements, a shape providing unit (50) configured to provide the printed circuit board (800, 1000) of a particular shape, and a filling unit (60) configured to determine the not-self-intersecting curve (510, 530, 540, 550, 560, 610, 620, 630, 640, 650, 660, 810, 1010) of a predetermined width so as to fill the shape of the printed circuit board (800, 1000).

2. The layout generation system (1) according to claim 1, wherein the light elements positioning unit (40) is configured to optimize the positions of the building blocks (22, 24, 26, 820, 920) of the electrical layout (220, 320) along the not-self-intersecting curve on the basis of at least one of color mixing and output flux homogeneity.

3. The layout generation system (1) according to claim 1, wherein the building blocks providing unit (20) is configured to dimension the electrical connections under consideration of a cooling requirement of the at least one light element.

4. The layout generation system (1) according to claim 1, wherein the building blocks (22, 24, 26, 820, 920) comprise at least one of a strip start building block, a light elements building block (22, 24, 26, 820, 920), a resistor block, and a strip end building block.

5. The layout generation system (1) according to claim 4, wherein the light elements building block (24, 26) comprises three light elements of different color.

6. The layout generation system (1) according to claim 1, wherein the predefined width of the curve corresponds at least to a width of the strip-like electrical layout (220, 320).

7. The layout generation system (1) according to claim 1, wherein the electrical layout generating unit (30) is configured to generate at least two separate electrical layouts of the printed circuit board (800, 1000), wherein each of the at least two separate electrical layouts is configured to independently create the desired luminance pattern, wherein the light elements positioning unit (40) is configured to position the light elements of the building blocks (22, 24, 26, 820, 920) of each of the electrical layouts along the not-self-intersecting curve.

8. The layout generation system (1) according to claim 7, further comprising a dividing unit (70) configured to divide the printed circuit board (800, 1000) into a number of sub-boards (1100, 1200, 1300, 1400), the number of sub-boards (1100,

1200, 1300, 1400) corresponding to the number of separate electrical layouts, wherein each of the sub-boards (1100, 1200, 1300, 1400) comprises all light elements of one of the separate electrical layouts.

9. The layout generation system (1) according to claim 8, wherein the dividing unit (70) is configured to divide the printed circuit board (800, 1000) using a meandering cut (1012) along the curve such that the cut intersects a center of the curve between two light elements of different separate electrical layouts.

10. The layout generation system (1) according to claim 9, wherein the light elements positioning unit (40) is configured to cyclically alternate light elements of each separate electrical layout along the curve.

11. The layout generation system (1) according to claim 8, wherein the dividing unit is configured to divide the printed circuit board (800, 1000) such that each of the obtained sub-boards (1100, 1200, 1300, 1400) provides a connected surface.

12. A layout generation method to generate a layout of a printed circuit board, the layout generation method (100) comprising: an optical requirements providing step (110) of providing optical requirements of a luminance pattern to be emitted by the printed circuit board (800, 1000), a building blocks providing step (120) of providing at least one type of building blocks (22, 24, 26, 820, 920), the at least one type of building blocks (22, 24, 26, 820, 920) comprising electrical connections to at least one adjacent building block (22, 24,

26, 820, 920) and at least one light element, an electrical layout generating step (130) of providing an electrical layout of the printed circuit board (800, 1000), the electrical layout comprising a linear connection of building blocks (22, 24, 26, 820, 920) in order to form a strip-like electrical layout (220,

320), a light elements positioning step (140) of positioning the light elements of the building blocks (22, 24, 26, 820, 920) of the electrical layout (220, 320) along a not-self- intersecting curve on the surface of the printed circuit board (800, 1000) under consideration of the optical requirements, a shape providing step of providing the printed circuit board (800, 1000) of a particular shape, and a filling unit step of determining the not-self-intersecting curve (510, 530, 540, 550, 560, 610, 620, 630, 640, 650, 660, 810, 1010) of a predetermined width so as to fill the shape of the printed circuit board (800, 1000).

13. An area light source comprising a printed circuit board generated by carrying out the layout generation method (100) according to claim 12 using the layout generation system (1) according to claim 1.

14. A computer program for generating a printed circuit board, the computer program comprising program code means for causing a layout generation system (1) as defined in claim 1 to carry out the layout generation method (100) as defined in claim 12, when the computer program is run on the layout generation system (1).