Patent Description:
LED-based devices are known in the art. <CIT>, for instance, describes a light emitting diode package comprising a package main body with a cavity; a plurality of light emitting diode chips mounted in the cavity; a wire connected to an electrode of at least one light emitting diode chip; and a plurality of lead frames formed in the package main body, wherein at least one lead frame is electrically connected to the light emitting diode chip or a plurality of wires. The plurality of light emitting diode chips include a horizontal light emitting diode chip with two electrodes disposed in a horizontal structure, and/or a vertical light emitting diode chip with electrodes disposed in a vertical structure. At least one of the light emitting diode chips includes a P electrode or an N electrode die-bonded to the lead frame.

<CIT> discloses a light emitting display with a light emitting diode chip. The light emitting display body composed of a light emitting diode chip, which is connected to a first conductive pattern formed on the back surface of the display body substrate via a through hole, and a conductive portion formed on the front surface of the display body substrate and a display. The light emitting portion base is formed by a part of the second conductive pattern insulated and separated from the conductive portion formed on the surface of the body substrate, and the conductive portion forming the light emitting portion base and the second conductive portion. A light emitting diode chip having a complementary relationship with each other is provided as a pair with each of a part of the conductive pattern, and the different polar upper surfaces of both of these light emitting diode chips are bridged and connected by a bonding wire to each of the light emitting parts. A light emitting display body using a light emitting diode chip, which comprises forming a series connection of two light emitting diode chips.

<CIT> discloses a vertical structure chip series connection structure and a series connection method, wherein the series connection structure comprises two vertical structure chips, a prefabricated substrate and a gold wire, wherein the two vertical structure chips comprise a vertical structure chip with an upward p electrode and a vertical structure chip with an upward n electrode; downward electrodes of the two vertical structure chips are respectively welded on the prefabricated substrate, the upward electrodes are connected by welding the gold wire, and the series connection of the vertical structure chips is realized. Therefore, the vertical structure chips are not connected through routing in the process of series connection, and the reliability is improved while the cost is greatly lowered.

It appears that there is a desire to provide light generating devices based on LEDs which may be operated at higher voltages than e.g. about <NUM> V for the blue and/or green LEDs and <NUM> V for the red LED. There appears a desire to provide light generating devices with an improved electrical design. Further, there appears to be a desire to provide compact light generating devices based on LEDs, especially in a relatively simple way. Further, there is a desire for relatively efficient solutions for light generating devices based on LEDs. Hence, it is an aspect of the invention to provide an alternative light generating device (and/or system comprising such device), which preferably further at least partly obviates one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

In a first aspect, the invention provides a light generating device ("device" or "lighting device") comprising (i) a first series of at least two first LEDs, which are electrically conductively coupled. Further, the device comprises (ii) a first support configured to support the at least two first LEDs. The at least two first LEDs comprise solid-state LEDs configured to generate red LED light. Further, the at least two first LEDs comprise a p-side up LED and an n-side up LED. The at least two LEDs are configured to generate essentially the same light, i.e. light having essentially the same spectral power distribution. In particular, the at least two first LEDs are configured to generate first LED light having dominant wavelengths within <NUM> of each other, such as within about <NUM> of each other. Therefore, especially the invention provides in embodiments a light generating device comprising (i) a first series of at least two first LEDs, which are electrically conductively coupled, and (ii) a first support configured to support the at least two first LEDs, wherein: (a) the at least two first LEDs comprise solid-state LEDs; and (b) the at least two first LEDs comprise a p-side up LED and an n-side up LED.

With such device, it is possible to provide a compact lighting solution. Further, it appears possible to drive longer wavelength LEDs, such as red LEDs, at higher voltages. With the present invention, it is also possible to provide a color tunable lighting device that may be relatively compact.

Especially, in specific embodiments the at least two first LEDs are configured to generate first LED light having dominant wavelengths within <NUM> of each other, such as within about <NUM>, like especially within about <NUM>. This may provide first light sources which may provide first light having essentially the same color point (even more especially essentially the same spectral power distribution).

Alternatively or additionally, in specific embodiments color points differ at maximum <NUM> for u' and/or at maximum <NUM> for v', such as at maximum <NUM> for u' and/or at maximum <NUM> for v', like at maximum <NUM> for u' and/or at maximum <NUM> for v'. Especially, for at least one of u' and v', the difference in the color points is at maximum <NUM>. This may provide first light sources which may provide first light having essentially the same color point.

As indicated above, the light generating device comprises a first series of at least two first LEDs, which are electrically conductively coupled. Especially, the at least two first LEDs are configured in series. When there are more than two first LEDs, two or more first LEDs may be configured parallel, though at least two LEDs are (also) configured in series. In specific embodiments, the light generating device may comprise a plurality of first series of each (at least) two first LEDs. Hence, the term "first series" may also refer to a plurality of first series. When there is more than one first series, the plurality of first series may be configured all in series. However, in (yet other) embodiments two or more first series may be configured parallel. Further, in specific embodiments wherein there are two or more first series, all first LEDs may be controlled as group. However, in other specific embodiments wherein there are two or more first series, two or more first series of the two or more first series may be controlled individually.

The term "electrically conductively coupled" especially refers to embodiments wherein a p electrode of one of the first LEDs in the first series is electrically conductively coupled to an n electrode of another one of the first LEDs in (the same) first series, or to embodiments wherein an n electrode of one of the first LEDs in the first series is electrically conductively coupled to a p electrode of another one of the first LEDs in (the same) first series. As will be further elucidated below, this electrically conductive coupling may in embodiments be provided by the first support.

Especially, the at least two first LEDs comprise solid-state LEDs. The first LEDs are especially configured to provide essentially first LED light. The first LED light may essentially be based due to electron-hole recombination by which a photon may be generated. Hence, the first LED may especially not comprise a luminescent material. Further embodiments of the first LED are described below. The presence of the at least two first LEDs does not exclude the availability of further LEDs, which may be of different types (see also further below).

As indicated above, the light generating device further comprises a first support configured to support the at least two first LEDs. In embodiments, the support may comprise or may be comprised by a PCB ("printed circuit board" or "board"). As known in the art, a printed circuit board may mechanically support and electrically connect electronic components or electrical components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a nonconductive substrate (shortly indicated as "track" or "conductive track"). Hence, in embodiments a PCB may comprise an insulating layer arranged between a substrate and a conductive layer. An (electronic) component, such as a solid stage light source, may generally be soldered onto the PCB to both electrically connect and mechanically fasten it to the PCB. For instance, a basic PCB may consist of a flat sheet of insulating material and a layer of copper foil, laminated to the substrate. Chemical etching divides the copper into separate conducting lines called tracks or circuit traces, pads for connections, vias to pass connections between layers of copper, and features such as solid conductive areas for EM shielding or other purposes. The tracks function as wires fixed in place, and are insulated from each other by air and the board substrate material. The surface of a PCB may have a coating that protects the copper from corrosion and reduces the chances of solder shorts between traces or undesired electrical contact with stray bare wires. For its function in helping to prevent solder shorts, the coating is called solder resist. the shape of a PCB may in general be plate-like. In specific embodiments, the board may comprise a printed circuit board. Especially, the board may comprise one or more of a CEM-<NUM> PCE, a CEM-<NUM> PCE, a FR-<NUM> PCE, a FR-<NUM> PCB, a FR-<NUM> PCB, a FR-<NUM> PCB, and aluminum metal core PCB, especially one or more of a CEM-<NUM> PCB, a CEM-<NUM> PCB, a FR-<NUM> PCB, and a FR4 PCB and an aluminum metal core PCB, more especially one or more of a CEM-<NUM> PCB, a CEM-<NUM> PCB, a FR-<NUM> PCB. In specific embodiments, the printed circuit may be flexible. In yet other embodiments, the printed circuit board may be rigid.

In embodiments, the at least two first LEDs comprise a p-side up LED and an n-side up LED. Instead of the term "n-side up LED" also the term "p-side down LED" may be applied. Likewise, of the term "p-side up LED" also the term "n-side down LED" may be applied. Herein further, especially the terms "p-side up LED" and "p-side up" and "n-side up LED" and "n-side up", respectively, are used. These terms and such LEDs are known in the art. It is for instance referred to <CIT>, <NPL>, <NPL>, which are herein incorporated by reference. Sometimes, p-side up is also indicated as "epi-up" and p-side down as "epi-down". Further, "p-side down" or "epi-down" may also be indicated as "flip chip".

As indicated above, the at least two first LEDs are "electrically conductively coupled". As in embodiments the at least two first LEDs comprise a p-side up LED and an n-side up LED, in embodiments the n-electrode of the p-side up and the p-electrode of the n-side up may be electrically conductively coupled via an electrical conductor, such as comprised by the first support. Such first support may comprise an electrical conductor, such as an electrically conductive track, which may be used to electrically conductively couple (e.g.) the n-electrode of the p-side up and the p-electrode of the n-side up. This allows a relatively compact arrangement and/or may allow a relatively easy processing.

As indicated also above, the at least two first LEDs comprise a p-side up LED and an n-side up LED. In this context, the phrase "first series of at least two first LEDs" may also refer to e.g. a first series comprise n sets of each a p-side up LED and an n-side up LED, like in specific embodiments a series of two p-side up LEDs and two n-side up LEDs. Here, n refers to a natural number of <NUM> or larger, such as n=<NUM> (see further also below). Especially, the n sets of each a p-side up LED and an n-side up LED are configured as serial configuration of (n-side up + p-side up)n. Herein, in general "n-side up + p-side up" is the same as "p-side up + n-side up".

As can amongst others be derived from the above cited documents, in embodiments the p-side up LED and an n-side up LED may (each) be obtainable by a combination of front-side processing and back-side processing of epitaxially grown layers. In specific embodiments, the n-side up LED is obtainable by a combination of front-side processing and back-side processing of epitaxially grown layers. Alternatively or additionally, in embodiments the p-side up LED is obtainable by front-side processing only of epitaxial grown layers. However, especially the p-side up LED may be obtainable by a combination of front-side processing and back-side processing of epitaxially grown layers. Hence, in embodiments the n-up LED may be obtainable by a one-time flip of the substrate. The p-up LED may in embodiments be obtainable by a two-times flip of the substrate.

Especially, in embodiments the at least two first LEDs may provide first LED light that is essentially the same. Hence, the first LED light of one of the at least two first LEDs may essentially be the same as the first LED light of another one of the at least two first LEDs. When there are more than two first LEDs in the first series, in embodiments all first LEDs in the first series may provide essentially the same light.

Here, the term "essentially the same light", and similar terms, may refer to embodiments wherein the first LED light of the first LEDs may have dominant wavelengths within about <NUM>, such as within about <NUM>, such as especially within about <NUM>. Therefore, in specific embodiments the at least two first LEDs are configured to generate first LED light having dominant wavelengths within <NUM> of each other. Especially, the first LED light of the first LEDs may have dominant wavelengths within about <NUM>. The term "dominant wavelength" is known in the art. The term "dominant wavelength" may refer to the wavelength of the monochromatic stimulus that, when additively mixed in suitable proportions with the specified achromatic stimulus, matches the color stimulus considered.

Here, the term "essentially the same light", and similar terms, may alternatively or additionally (in specific embodiments) also indicate that the respective color points differ at maximum <NUM> for u' and/or at maximum <NUM> for v'. Here, u' and v' are color coordinate of the light in the CIE <NUM> UCS (uniform chromaticity scale) diagram.

Hence, the first LEDs, even though being different in the sense that one may be p-up and the other may be n-up, the active layers may essentially be the same such that the light generated by the different first LEDs may be essentially the same. The (shape of the) spectral power distributions may in embodiments thus be essentially the same.

The above described device, comprising (i) a first series of at least two first LEDs, which are electrically conductively coupled, and (ii) a first support configured to support the at least two first LEDs, wherein: (a) the at least two first LEDs comprise solid-state LEDs; and (b) the at least two first LEDs comprise a p-side up LED and an n-side up LED, and wherein in specific embodiments the at least two first LEDs are configured to generate first LED light having dominant wavelengths within <NUM> of each other, may especially be able to generate light ("device light") when a voltage is applied over the series.

Hence, in specific embodiments the device may further comprise an electrical power source. Especially, the electrical power source is configured to apply a voltage difference over the first series of the at least two first LEDs (during an operational mode of the device). Further, especially the voltage may be controllable. To this end, the device may further comprise a control system, which may especially be configured to control the voltage over the first series. Hence, in specific embodiments (of the light generating device), the device may further comprise an electrical power source and a control system, wherein the electrical power source and the control system are configured to apply a controllable voltage difference over the first series of the at least two first LEDs. Note that in embodiments the electrical power source and the control system may be an integrated system.

In specific embodiments, in an operational mode of the device the electrical power source and the control system are configured to apply (in an operational mode) a voltage difference selected from the range of <NUM>-<NUM> V over the first series of the at least two first LEDs, especially selected from the range of <NUM>-<NUM> V, even more especially selected from the range of <NUM>-<NUM> V, such as <NUM> V or <NUM> V. For instance, this may be the voltage at maximum power when the first series comprises a (single) p-side up LED and a (single) n-side up LED. Would there two first series of each a p-side up and an n-side up be configured in series, i.e. two p-side up LEDs and two n-side up LEDs, the voltage thereover may especially be selected from the range of <NUM>-<NUM> V. Note that the phrase "two first series of each a p-side up LED and an n-side up LED be configured in series" may also be indicated as a first series comprising two p-side up LEDs and two n-side up LEDs. Hence, in specific embodiments the voltages over the first series may be selected from the range of <NUM>-<NUM> V. Therefore, in specific embodiments the first series comprises either (a) a single p-side up LED and a single n-side up LED (which may in embodiments be driven with a voltage selected from the range of <NUM>-<NUM> V), or (b) the first series comprises two p-side up LEDs and two n-side up LEDs (which may in embodiments be driven with a voltage selected from the range of <NUM>-<NUM> V).

Further, especially series with single blue or single green LEDs may be driven at a voltage selected from the range of <NUM>-<NUM> V, such as e.g. <NUM> V or <NUM> V.

The control system may also be configured to receive and execute instructions form a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or I-phone, a tablet, etc.. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

The system, or apparatus, or device may execute an action in a "mode" or "operation mode" or "mode of operation". Likewise, in a method an action or stage, or step may be executed in a "mode" or "operation mode" or "mode of operation" or "operational mode". The term "mode" may also be indicated as "controlling mode". This does not exclude that the system, or apparatus, or device may also be adapted for providing another controlling mode, or a plurality of other controlling modes. Likewise, this may not exclude that before executing the mode and/or after executing the mode one or more other modes may be executed.

In specific embodiments, the solid-state LEDs comprise AlGaInP based LEDs. Hence, the first LEDs of the first series may all be AlGaInP based LEDs. For instance, Th. Gessmann et al. (see also above), described such LEDs.

In specific embodiments, the at least two first LEDs comprise omni-directional reflectors ("ODR"). ODRs are describe in amongst others <NPL>, and also in Th. Gessmann et al.

AlGaInP based LEDs may be most efficient above about <NUM>, but may be able to emit at wavelengths down to about <NUM> (but at lower efficiencies than above about <NUM>), or even down to about <NUM>. Further, AlGaInP based LEDs may be able to emit at wavelengths up to about <NUM>. Therefore in specific embodiments the AlGaInP based LEDs are (each) configured to generate first light having a wavelength selected from the range of <NUM>-<NUM>. Hence, in embodiments the solid-state LEDs are configured to generate red LED light. Alternatively, in embodiments the solid-state LEDs are configured to generate green LED light. Other colors, such as yellow or orange may also be possible. Hence, alternatively in embodiments the solid-state LEDs are configured to generate yellow LED light or orange LED light. Further, note that in specific embodiments there may be more than one (first) series, wherein LEDs in different series may be configured to provide different colors, respectively. The terms "violet light" or "violet emission" especially relates to light having a wavelength in the range of about <NUM>-<NUM>. The terms "blue light" or "blue emission" especially relates to light having a wavelength in the range of about <NUM>-<NUM> (including some violet and cyan hues). The terms "green light" or "green emission" especially relate to light having a wavelength in the range of about <NUM>-<NUM>. The terms "yellow light" or "yellow emission" especially relate to light having a wavelength in the range of about <NUM>-<NUM>. The terms "orange light" or "orange emission" especially relate to light having a wavelength in the range of about <NUM>-<NUM>. The terms "red light" or "red emission" especially relate to light having a wavelength in the range of about <NUM>-<NUM>. The term "pink light" or "pink emission" refers to light having a blue and a red component.

Hence, especially the first LEDs may be configured to generate visible light. Even more especially, the first LEDs may, e.g. in examples not forming part of the invention, be configured to generate visible light having a wavelength selected from the range of <NUM>-<NUM> (see also above), such as having a dominant wavelength within this range. Would in embodiments further LEDs be available (see also below), in specific embodiments such further LEDs may also be configured to generate visible light. The terms "visible", "visible light" or "visible emission" and similar terms refer to light having one or more wavelengths in the range of about <NUM>-<NUM>.

With the above defined first series of at least two LEDs it may in embodiments be possible to provide device light with an essentially non-tunable spectral power distribution. Would that be desirable, a plurality of individually controllable first series should be applied. Alternatively, another series of one or more light sources, especially solid states light sources may be applied. Such further series of one or more solid state light sources, be it similar type of solid state light sources as the first series, or other type of solid state light sources are herein indicated as second series, third series, etc.. Here below, some embodiments in relation to a second series and a second series and a third series are further elucidated. However, more than three different series may in embodiments also be possible. Hence, in specific embodiments the term "third" may refer to third and one or more further.

Hence, the light generating device according to the invention is further comprising (i) a second series of one or more second LEDs. Such second series comprises one or more second LEDs. Such one or more LEDs may be of the same type as described above, and may provide LED light having essentially the same spectral power distribution as of the first LEDs. Hence, in (very) specific embodiments the second series at least two second LEDs comprise a p-side up LED and an n-side up LED, in embodiments the n-electrode of the p-side up and the p-electrode of the n-side up may be electrically conductively coupled via an electrical conductor, such as comprised by a second support (see also above). Especially, however, in embodiments the second LEDs are configured to provide second LED light having a spectral power distribution different from the first LED light. Hence, in embodiments of the invention the at least two first LEDs and the one or more second LEDs are configured to generate first LED light and second LED light, respectively, having different colors.

As can be derived from the above, the term "different colors" may especially imply in embodiments that that the respective color points differ at least about <NUM>. Hence, the wavelengths of the dominant wavelengths may differ at least about <NUM>.

As can be derived from the above, the term "different colors" may especially imply in embodiments that that the respective color points differ at least <NUM> for u' and/or at least <NUM> for v', such as at least <NUM> for u' and/or at least <NUM> for v', like especially at least <NUM> for u' and/or at least <NUM> for v'.

Hence, with respect to the second LED or second LEDs the same embodiments as described in relation to the first LEDs may apply, though especially there is a difference in spectral power distribution, more especially in the color of the first LED light and the second LED light. Hence, in specific embodiments there are at least two second LEDs which are "electrically conductively coupled". In yet further specific embodiments the at least two second LEDs comprise a p-side up LED and an n-side up LED, wherein in yet further specific embodiments the n-electrode of the p-side up and the p-electrode of the n-side up may be electrically conductively coupled via an electrical conductor, such as comprised by a second support.

The one or more second LEDs are supported by a second support, which may be comprised by a larger support also comprising the first support (see also below). Such second support may comprise an electrical conductor, such as an electrically conductive track, which may be used to electrically conductively couple two or more second LEDs, such as in specific embodiments the n-electrode of the p-side up and the p-electrode of the n-side up. This allows a relatively compact arrangement and/or may allow a relatively easy processing. Note, however, that the second series may also comprise a single second LED. As indicated above, the light generating device may further comprise a second support configured to support the one or more second LEDs. Therefore, in specific embodiments the light generating device may further comprise (i) a second series of one or more second LEDs, and (ii) a second support configured to support the one or more second LEDs, wherein the at least two first LEDs and the one or more second LEDs are configured to generate first LED light and second LED light, respectively, having different colors (such as having color points that differ at least <NUM> for u' and/or at least <NUM> for v').

In specific embodiments, the light generating device is configured to generate device light comprising one or more of the first LED light and the second LED light, wherein the light generating device further comprises the electrical power source and the control system as defined herein, wherein the electrical power source and the control system are configured to apply a controllable first voltage difference over the first series of the at least two first LEDs and a controllable second voltage difference over the second series of the one or more second LEDs. In specific embodiments, in an operational mode the device light is white device light (see further also below).

Especially, the one or more second LEDs are solid state light sources. As indicated above, in specific embodiments the one or more second LEDs may be AlGaInP based LEDs.

The light generating device of the invention is further comprising (i) a third series of one or more third LEDs. Such third series comprises one or more third LEDs. Such one or more LEDs may be of the same type as described above (in relation to the first LEDs (and optionally the second LEDs), and may, in embodiment not forming part of the invention as claimed, provide LED light having essentially the same spectral power distribution as of the first LEDs. Hence, in (very) specific embodiments the third series comprising at least two third LEDs may comprise a p-side up LED and an n-side up LED, in embodiments the n-electrode of the p-side up and the p-electrode of the n-side up may be electrically conductively coupled via an electrical conductor, such as comprised by a third support (see further also below). Especially, however, in embodiments according to the invention the third LEDs are configured to provide third LED light having a spectral power distribution different from the first LED light (and from the second LED light). Hence, especially in accordance with the invention the at least two first LEDs, the second LEDs, and the one or more third LEDs are configured to generate first LED light, second LED light, and third LED light, respectively, having different colors.

As indicated above, the term "different colors" may especially imply that that the respective color points differ at least <NUM> for u' and/or at least <NUM> for v', such as at least <NUM> for u' and/or at least <NUM> for v', like especially at least <NUM> for u' and/or at least <NUM> for v'.

Hence, with respect to the third LED or third LEDs the same embodiments as described in relation to the first LEDs and optionally the second LEDs) may apply, though especially there is a difference in spectral power distribution, more especially in the color of the first LED light, the second LED light, and the third LED light. Hence, in specific embodiments there are at least two third LEDs which are "electrically conductively coupled". In yet further specific embodiments the at least two third LEDs comprise a p-side up LED and an n-side up LED, wherein in yet further specific embodiments the n-electrode of the p-side up and the p-electrode of the n-side up may be electrically conductively coupled via an electrical conductor, such as comprised by a third support.

The first LEDs are solid state LEDs. Hence, the first LED light is the first light. Likewise, the second LEDs may (essentially) be solid state LEDs. Hence, the second LED light is the second light. Likewise, the third LEDs may (essentially) be solid state LEDs. Hence, the third LED light may (essentially) be the third light.

The one or more third LEDs are supported by a third support, which may be comprised by a larger support also comprising the first support and the second (see also below). Such third support may comprise an electrical conductor, such as an electrically conductive track, which may be used to electrically conductively couple two or more third LEDs, such as in specific embodiments the n-electrode of the p-side up and the p-electrode of the n-side up. This allows a relatively compact arrangement and/or may allow a relatively easy processing. Note, however, that the third series may also comprise a single third LED. Hence, in embodiments the light generating device is, according to the invention as claimed, further comprising (i) a third series of one or more third LEDs, and (ii) a third support configured to support the one or more third LEDs, wherein the at least two first LEDs, the one or more second LEDs, and the one or more third LEDs are configured to generate first LED light, second LED light, and third light, respectively, having different colors (such as having color points that differ at least <NUM> for u' and/or at least <NUM> for v').

In the embodiments according to the invention, the light generating device is comprising (i) a first series of at least two first LEDs, which are electrically conductively coupled, and (ii) a first support configured to support the at least two first LEDs, wherein:.

the one or more second LEDs comprising a p-electrode and a n-electrode on the same side, and the one or more third LEDs comprising a p-electrode and a n-electrode on the same side.

The obtained effect is an improved light generating device (e.g. a RGB LED package) having an improved electrical design and/or compact shape. The light generating device providing red light and other colors has an improved electrical design while being compact. The voltage (V) and/or current (I) characteristics (obtained by the particular configuration) of the first series of at least two first LEDs are better matched with the second series of one or more second LEDs and third series of one or more third LEDs.

Especially, the one or more third LEDs are solid state light sources.

In yet further specific embodiments, the light generating device is configured to generate device light comprising one or more of the first LED light, the second LED light, and the (optional) third LED light as defined herein, wherein the light generating device further comprises the electrical power source and the control system as defined herein, wherein the electrical power source and the control system are configured to apply a controllable first voltage difference over the first series of the at least two first LEDs, a controllable second voltage difference over the second series of the one or more second LEDs, and a controllable third voltage difference over the (optional) third series of the one or more third LEDs. In yet more specific embodiments, in an operational mode the device light is white device light.

The term "white light" herein, is known to the person skilled in the art. It especially relates to light having a correlated color temperature (CCT) between about <NUM> and <NUM>, such as between <NUM> and <NUM>, especially <NUM>-<NUM>, for general lighting especially in the range of about <NUM> and <NUM>. In embodiments, for backlighting purposes the correlated color temperature (CCT) may especially be in the range of about <NUM> and <NUM>. Yet further, in embodiments the correlated color temperature (CCT) is especially within about <NUM> SDCM (standard deviation of color matching) from the BBL (black body locus), especially within about <NUM> SDCM from the BBL, even more especially within about <NUM> SDCM from the BBL.

As indicated above, the light generating device may comprise a (main) support, wherein the (main) support comprises the first support, the second support, and the optional third support. Such (main) support may comprise a PCB. See further above for embodiments of the PCB. Hence, in embodiments the first support, the second support, and the optional third support may be parts of a (main support). Especially, in embodiments the first support, the second support, and the optional third support are enclosed by the same housing.

In specific embodiments, the light generating device comprises the (main) support, which (is configured) to support (I) the first series comprises either (a) a single p-side up LED and a single n-side up LED (which may in embodiments be driven with a voltage selected from the range of <NUM>-<NUM> V), or (b) the first series comprises two p-side up LEDs and two n-side up LEDs (which may in embodiments be driven with a voltage selected from the range of <NUM>-<NUM> V); (II) the second series of one or more second LEDs, especially the second series comprising a single LED; and (III) the third series of one or more third LEDs, especially the third series comprising a single LED. Optionally, further series may be available. Especially, the LEDs of the respective series are configured to generate LED light that differs, like e.g. RGB. For instance, the first series is configured to generate red light, the second series may be configured to generate green light and the third series may be configured to generate blue light. In this way a gamut of color points (of the device light) may be obtainable.

In specific embodiments, the light generating device comprises the (main) support, which (is configured) to support (I) the first series comprises either (a) a single p-side up LED and a single n-side up LED (which may in embodiments be driven with a voltage selected from the range of <NUM>-<NUM> V), or (b) the first series comprises two p-side up LEDs and two n-side up LEDs (which may in embodiments be driven with a voltage selected from the range of <NUM>-<NUM> V); and (II) the second series of one or more second LEDs, especially the second series comprising a single LED. Optionally, further series may be available. Especially, the LEDs of the respective series are configured to generate LED light that differs, like e.g. in embodiments whitish light (such as white light having a high color temperature; or off-white with a relatively high contribution of green and/or blue, especially both) from the second series, and red light (from the first series). For instance, the first series may be configured to generate red light, the second series may be configured to generate white or whitish light. In this way, e.g. the color temperature (of the device light) may be controlled.

In specific embodiments, in an operational mode the control system is configured to control the correlated color temperature of the device light while maintaining a constant flux of the device light. Such operational mode may also be indicated with the reference "M2". Alternatively or additionally, in an(other) operational mode the control system is configured to control the correlated color temperature of the device light while maintaining a maximum flux of the device light. Such operational mode may also be indicated with the reference "M1".

The lighting device may be part of or may be applied in e.g. office lighting systems, household application systems, shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fiber-optics application systems, projection systems, self-lit display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems, automotive applications, (outdoor) road lighting systems, urban lighting systems, green house lighting systems, horticulture lighting, etc.. In embodiments, the light generating device may be a T-LED or a downlight luminaire. In yet other embodiments, the light generating device may be comprised by a T-LED or a downlight luminaire.

In yet a further aspect, the invention provides a light generating system comprising the light generating device as defined herein and a communication system for a wireless control of the control system. For instance, the communication system may be comprised by the light generating device as defined above. However, in embodiments the communication system may also be external of one or more, especially a plurality, of the light generating devices comprised by the system. The communication system may be a master slave system with an external master communication system, and with each light generating device comprising a slave communication system. Likewise, the control system may be a master-slave system with an external master control system, and with each light generating device comprising a slave control system. Further, the communication system may be comprised by the control system or may be functionally coupled to the control system. The control system may e.g. comprise a "bridge" or Wi-Fi router, etc. Hence, in specific embodiments the light generating device is comprised by a connected lighting system. Hence, the light generating system may comprise two or more light generating devices which are connected. For instance, communication between light generating devices may be via Bluetooth, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology.

The phrases "different light sources" or "a plurality of different light sources", and similar phrases, may in embodiments refer to a plurality of solid state light sources selected from at least two different bins. Likewise, the phrases "identical light sources" or "a plurality of same light sources", and similar phrases, may in embodiments refer to a plurality of solid state light sources selected from the same bin.

In alternative embodiments, the dominant wavelengths of two first light sources of the at least two first light sources of the first series may differ with a value selected from the range of <NUM>-<NUM> (i.e. they may not differ or may differ with up to <NUM>), such as selected from the range of <NUM>-<NUM> (in accordance with the claimed invention), like <NUM>-<NUM>.

In specific embodiments, the light generating device comprising: (i) more first LEDs than second LEDs, and more first LEDs than third LEDs.

In specific embodiments, the light generating device comprising N second LEDs and M third LEDs, wherein N = M.

In specific embodiments, the light generating device comprising N second LEDs and M third LEDs, and the light generating device comprising Z first LEDs, wherein the ratio Z : N : M = <NUM> : <NUM> : <NUM>. For example, the lighting device may comprise <NUM> first LEDs, <NUM> second LED and <NUM> third LED, the lighting device may comprise <NUM> first LEDs (e.g. <NUM> p-side up LEDs and <NUM> n-side up LEDs), <NUM> second LEDs and <NUM> third LEDs, or the lighting device may comprise <NUM> first LEDs (e.g. <NUM> p-side up LEDs and <NUM> n-side up LEDs), <NUM> second LED and <NUM> third LEDs.

In specific embodiments, like the embodiments of the invention, the first LEDs emit red LED light.

In specific embodiments, the second LEDs emit green LED light.

In specific embodiments, the third LEDs emit (orange and/or) red LED light.

In specific embodiments, the first series of at least two first LEDs emit red LED light.

In specific embodiments, the second series of one or more second LEDs emit green LED light.

In specific embodiments, the third series of one or more third LEDs emit (orange and/or) red LED light.

In the embodiments according to the invention, the second LEDs are comprising a p-electrode and a n-electrode on the same side, and the third LEDs are comprising a p-electrode and a n-electrode on the same side. The same side may be on a top surface or on a bottom surface of the LED. Such type of LEDs are easy and low to mount and/or manufacture.

In specific embodiments, one of the following applies:.

The obtained effect of previous embodiments is a further improved light generating device (e.g. a RGB LED package). The light generating device has an improved electrical design and/or is more compact. The voltage (V) and/or current (I) characteristics of the first series of at least two first LEDs are even better matched with the second series of one or more second LEDs and third series of one or more third LEDs, thus an improved electrical design. Such configuration allows for a simple and/or low-cost design of the light generating device (e.g. an RGB LED package) and/or a allows for a simple and/or low-cost design of a controller/driver which can be used for said light generating device. Furthermore, such device is compact.

<FIG> schematically depicts an embodiment of a light generating device <NUM>. The light generating device <NUM> comprises a first series <NUM> of at least two first LEDs <NUM>, which are electrically conductively coupled. Further, the light generating device <NUM> comprises a first support <NUM> configured to support the at least two first LEDs <NUM>.

In accordance with the invention, the at least two first LEDs <NUM> comprise solid-state LEDs <NUM>. Especially, the at least two first LEDs <NUM> comprise a p-side up LED <NUM> and an n-side up LED <NUM>. Further, in specific embodiments the at least two first LEDs <NUM> are configured to generate first LED light <NUM>, e.g. having dominant wavelengths within <NUM> of each other.

In embodiments, the p-side up LED <NUM> and an n-side up LED <NUM> are (both) obtainable by a combination of front-side processing and back-side processing of epitaxially grown layers. These front-side processing and back-side processing may thus differ, see further also below. In alternative embodiments, instead of the p-side up obtainable by a combination of front-side processing and back-side processing of epitaxially grown layers, normal epitaxially grown p-up LED may be chosen.

In embodiments, the solid-state LEDs <NUM> may comprise AlGaInP based LEDs.

Further, in specific embodiments the solid-state LEDs <NUM> may be configured to generate red LED light <NUM>, or green LED light <NUM>, or yellow LED light <NUM>, or orange LED light <NUM>.

As further schematically depicted, the light generating device <NUM> may further comprise an electrical power source <NUM> and a control system <NUM>. In specific embodiments, the electrical power source <NUM> and the control system <NUM> may be configured to apply a controllable voltage difference over the first series <NUM> of the at least two first LEDs <NUM>. Further, in specific embodiments in an operational mode of the device <NUM> the electrical power source <NUM> and the control system <NUM> are configured to apply a voltage difference selected from the range of <NUM>-<NUM> V, such as <NUM>-<NUM> V, like <NUM>-<NUM> V, over the first series <NUM> of the at least two first LEDs <NUM>. This may refer to an operational mode wherein the maximum power is provided to the first series of first LEDs.

<FIG> in fact also schematically depicts an embodiment of a light generating system <NUM> comprising the light generating device <NUM> and a communication system <NUM> for a wireless control of the control system <NUM>. The system may comprise a lamp including all elements. However, the system <NUM> may also comprise a lamp and an external control system (see also e.g. below).

<FIG> schematically depicts an embodiment according to the invention as claimed wherein the light generating device <NUM> further comprises a second series <NUM> of one or more second LEDs <NUM>. Yet further, in embodiments the light generating device <NUM> as schematically depicted (or other embodiments) further comprises, in accordance with the invention, a second support <NUM> configured to support the one or more second LEDs <NUM>. Especially, the at least two first LEDs <NUM> and the one or more second LEDs <NUM> are configured to generate first LED light <NUM> and second LED light <NUM>, respectively, having different colors. In <FIG>, also schematically an embodiment is depicted wherein the light generating device <NUM> further comprises, in accordance with the invention, a third series <NUM> of one or more third LEDs <NUM> and a third support <NUM> configured to support the one or more third LEDs <NUM>. Especially, the at least two first LEDs <NUM>, the one or more second LEDs <NUM>, and the one or more third LEDs <NUM> are configured to generate first LED light <NUM>, second LED light <NUM>, and third light <NUM>, respectively, having different colors.

As schematically depicted, the light generating device <NUM> may further comprise a support <NUM>, wherein the support <NUM> comprises the first support <NUM>, the second support <NUM>, and the optional third support <NUM>.

Especially, all LEDs <NUM>, <NUM>, <NUM> are solid state LEDs, indicated with reference <NUM>. However, these solid state LEDs may emit (solid state) light <NUM> at different wavelengths. The first LEDs are solid state LEDs. Hence, the first LED light may be the first light. Likewise, the second LEDs may be solid state LEDs. Hence, the second LED light may be the second light. Likewise, the third LEDs may be solid state LEDs. Hence, the third LED light may be the third light.

As also schematically depicted in <FIG>, the light generating device <NUM> is configured to generate device light <NUM> comprising one or more of the first LED light <NUM>, the second LED light <NUM>, and the third LED light <NUM>. The light generating device <NUM> may (thus) further comprise the electrical power source <NUM> and the control system <NUM>. In specific embodiments, the electrical power source <NUM> and the control system <NUM> may be configured to apply a controllable first voltage difference over the first series <NUM> of the at least two first LEDs <NUM>, a controllable second voltage difference over the second series <NUM> of the one or more second LEDs <NUM>, and a controllable third voltage difference over the optional third series <NUM> of the one or more third LEDs <NUM>. Further, in specific embodiments in an operational mode of the device <NUM>, the device light <NUM> may be white device light <NUM>.

<FIG> schematically depicts another embodiment of a light generating system <NUM> comprising the light generating device <NUM> and a communication system <NUM> for a wireless control of the control system <NUM>. Here, the light generating system <NUM> comprises a plurality of light generating devices and an external control system. For instance, the light generating devices <NUM> may be hue devices. Further, in specific embodiments the light generating device may be able to communicate between one another. In this way a control signal may be communicated from one light generating device <NUM> to another. Reference <NUM> indicates a slave controller and reference <NUM> a master controller. References <NUM> indicates a user interface, such as a graphical user interface. For instance, such interface may be comprised by or provided by a Smartphone or I-phone or other portable (communication) device.

<FIG> schematically depicts an embodiment wherein the light generating device <NUM> is selected from the group consisting of a T-LED and downlight luminaire. Here, the light generating device comprises a T-LED.

<FIG> schematically depicts two embodiments wherein on the x-axis the correlated color temperature (CCT) in Kelvin is indicated, and the y-axes (not indicated) represent the flux of the device light and power. Examples of flux (F) and power (P) curves are indicated, with on the left an embodiment wherein e.g. the control system may be is configured to control the correlated color temperature of the device light while maintaining a constant flux of the device light (M2 embodiment), and on the right an embodiment wherein the control system may be configured to control the correlated color temperature of the device light while maintaining a maximum flux of the device light. Such operational mode may also be indicated with the reference "M1". Other shapes of the curve on the right may of course also be possible. The curves are especially indicated to show that the dependence on the CCT is approximately the same.

With reference to Gessmann et al. , the following information in relation to p-side up and n-side up LED is herein incorporated: Two fabrication routes for AlGaInP-based ODR LEDs n-type up or p-type up are shown schematically in <FIG>. Both processes start out with "p-side up" epiwafers, which are the standard for epitaxial growth, and include front- and backside processing of the ODR-LED, removal of the original substrate, and bonding to a conductive carrier. The conductive carrier should ensure good heat sinking and should be thermal-expansion matched with respect to the epilayer. The p-type up process involves more steps ~due to the use of a temporary holder, but has the potential for lower contact resistances at the LED backside contact since the small-area contact pattern is applied to n-type material. The n-type up process does not require a temporary holder but the backside ohmic contacts are to p-type material, which likely results in higher contact resistances. Chemo-mechanical polishing can be employed to thin the GaAs wafer down to a thickness of about <NUM>-<NUM>. The remaining layer can then be removed by selective wet chemical etching. The wet-chemical etching step, however, requires one or more etch stop layers covering the bottom window layer of the LED to prevent etch damage. With optimized thickness, composition, and sequence of several etch stop layers the damage to the lower window layer can be minimized. The epitaxial ODR LED layer needs to be bonded to a permanent holder. Several materials are suited as holders: Si and metal substrates have high thermal conductivity when compared to GaAs or GaP and therefore provide for efficient heat sinking. However, suitable holder materials have to ensure thermal expansion matching, which is required to avoid stress damage to the LED during processing steps at elevated temperatures. The bonding process has to result in a uniform large-area bond between the substrate and the LED, which is able to sustain temperature cycling required during further LED processing such as annealing of electrical contacts. The bond may be accomplished by forming a binary intermetallic compound located between the conductive holder and the LED epilayer. For this purpose, the bonding surfaces may be covered either directly with the alloy or with the two separate components in a layer sequence with individual thicknesses ensuring the correct alloy composition. Subsequently the two surfaces are stacked face-to-face and annealed. The bonding is mediated by solid phase reactions such as solid-phase epitaxial regrowth at the alloy/epilayer and the alloy/holder interfaces. Preferably, it also involves liquid-phase reactions that help to reduce surface roughness. The bonding material should adhere to the LED epilayer as well as to the holder and should have low electrical resistance. The bonding process should take place at sufficiently low temperatures in order to avoid dopant redistribution in the heterostructure. Note that the requirements for the bonding process discussed above are less critical than for the semiconductor-to-semiconductor bonding processes used in TS technology. As an example, the AuGe intermetallic compound is capable of forming low-resistivity contacts to n-type GaAs and can therefore be employed to bond the ODR-LED epilayer to a GaAs holder. AuGe forms a eutectic phase during the bonding process at temperatures close to the melting point Tm=<NUM> of the eutectic. Other systems such as PdIn with a transient liquid phase have been used for bonding of GaN epilayers to Si. An alternate possibility to permanently bond the epilayer to a holder is the use of silver-loaded epoxy. The epoxy offers excellent electrical conductivity, adhesion, and bond strength. It can be easily and uniformly dispensed on the sample and is extremely reliable. However, during subsequent contact annealing the degradation temperature of the epoxy polymer TD≈<NUM> must not be exceeded. In addition, the thermal expansion is different from GaP and therefore thermal expansion matching is difficult.

In <FIG>, reference EL indicates epitaxial layers and reference S indicates a substrate. Reference C indicates a contact, in <FIG> a p-type contact, which is here thus p-side up configured. Reference TH indicates a temporary holder. Reference C1 are micro contacts, in <FIG> of the p-side up LED and in <FIG> of the n-side up LED. Reference R indicates the omnidirectional reflector.

Hence, <FIG> also schematically depict an embodiment wherein first LED <NUM> comprises omni-directional reflectors.

Amongst others, it is further referred to embodiments described by Chen-Fu Chu et al. , such as in <FIG>.

The term "comprise" includes also embodiments wherein the term "comprises" means "consists of".

Claim 1:
A light generating device (<NUM>) comprising (i) a first series (<NUM>) of at least two first LEDs (<NUM>), which are electrically conductively coupled, and (ii) a first support (<NUM>) configured to support the at least two first LEDs (<NUM>), wherein:
- the at least two first LEDs (<NUM>) comprise solid-state LEDs (<NUM>) configured to generate red LED light (<NUM>); and
- the at least two first LEDs (<NUM>) comprise a p-side up LED (<NUM>) and an n-side up LED (<NUM>), and wherein the at least two first LEDs (<NUM>) are configured to generate first LED light (<NUM>) having dominant wavelengths within <NUM> of each other;
- the light generating device further comprising (i) a second series (<NUM>) of one or more second LEDs (<NUM>), and (ii) a second support (<NUM>) configured to support the one or more second LEDs (<NUM>); and
- the light generating device further comprising (i) a third series (<NUM>) of one or more third LEDs (<NUM>), and (ii) a third support (<NUM>) configured to support the one or more third LEDs (<NUM>), wherein:
- the at least two first LEDs (<NUM>), the one or more second LEDs (<NUM>), and the one or more third LEDs (<NUM>) are configured to generate first LED light (<NUM>), second LED light (<NUM>), and third LED light (<NUM>), respectively, having different colors;
- the one or more second LEDs comprising a p-electrode and a n-electrode on the same side, and the one or more third LEDs comprising a p-electrode and a n-electrode on the same side.