EP4736236A1

EP4736236A1 - Lighting arrangement

Info

Publication number: EP4736236A1
Application number: EP24733646.4A
Authority: EP
Inventors: Ties Van Bommel
Original assignee: Signify Holding BV
Current assignee: Signify Holding BV
Priority date: 2023-06-27
Filing date: 2024-06-24
Publication date: 2026-05-06
Also published as: WO2025003056A1; CN121400102A

Abstract

A lighting arrangement comprises a respective plurality of first and second light emitting diodes M-LEDs, N-LEDs, arranged on a carrier. Each of the M-LEDs comprising a die having a first surface area SA1 with a largest spatial extent SE1 that is at most 100 micrometers. The N-LEDs are arranged on the carrier, each of the N-LEDs comprising a die having a second surface area SA2 with a largest spatial extent SE2 that is at most 300 micrometers. The M-LEDs emit first light LG1 having a first emission peak wavelength in ultraviolet, violet and/or blue light. The N-LEDs emit second light LG2 having a second emission peak wavelength, in green and/or red light. A ratio defined by SA2/SA1 is equal to or larger than 10. The arrangement light is white light having a correlated color temperature, CCT, in a range 2000-6500K and a color rendering index of at least 80.

Description

LIGHTING ARRANGEMENT

FIELD OF THE INVENTION

The present invention generally relates to lighting arrangements configured to provide white light. More specifically, the present invention is related to a lighting arrangement comprising a plurality of light emitting diodes (LEDs).

BACKGROUND OF THE INVENTION

A trend in the development of LED lighting is the development of long- lifetime products, for example lighting arrangements that are capable of 100.000 hours operation. Other trends in this development include use of low-cost materials for optical components, decrease of material use in optical components to achieve a lower environmental impact, introduction of biodegradable/bio-based materials for optical components for sustainability. However, these materials are susceptible for blue light (440- 470nm), especially for short wavelength blue light (420-440nm), and more specially for violet light (380-420nm) or even more specially for UV light (<380nm), resulting in an increased risk of browning of the optical components. Since these LEDs may be used in applications such as color point tunable and disinfection lighting, browning of the components is a drawback which has to be addressed.

SUMMARY OF THE INVENTION

It is of interest to provide a lighting arrangement that overcomes drawbacks of the prior art as discussed above.

This and other objects are achieved in a first aspect by providing a lighting arrangement having the features of the appended independent claim. Preferred embodiments are defined in the appended dependent claims.

Hence, according to the present invention, there is provided a lighting arrangement configured to provide arrangement light. The lighting arrangement comprises a carrier, a plurality of first light emitting diodes (M-LEDs) arranged on the carrier, each of the M-LEDs comprising a die having a first surface area (SAI), wherein the SAI has a largest spatial extent (SEI) that is less than or equal to 100 micrometers. A plurality of second light emitting diodes (N-LEDs) are arranged on the carrier, each of the N-LEDs comprising a die having a second surface area (SA2), wherein the SA2 has a largest spatial extent (SE2) that is greater than or equal to 300 micrometers.

Note that where reference is made to surface area, this relates to the epitaxial or epitaxy (in short ‘epi’) surface area of the die which may only be on the top surface of the die.

The M-LEDs are configured to emit first light (LG1) having a first emission peak wavelength (XI) in a wavelength range of ultraviolet light (UV), violet light (V) and/or blue light (B). The N-LEDs are configured to emit second light (LG2) having a second emission peak wavelength (X2), in a wavelength range of green light (G) and/or red light (R). A ratio (Rl) defined by SA2/SA1 is equal to or larger than 10. The arrangement light is white light having a correlated color temperature, CCT, in a range from 2000K to 6500K and a color rendering index (CRI) of at least 80 or at least 85.

UV light is light in the wavelength range from lOOnm to 380nm. UVA light is UV light in the wavelength range from 315nm to 380nm. UVB light is UV light in the wavelength range from 280nm to 315nm. UVC light is UV light in the wavelength range from lOOnm to 280nm. Violet light is light in the wavelength range 380nm to 420nm. Violet light in the wavelength range 400nm to 420 nm (i.e. Violet II light) is more safe than violet light in the wavelength range 380nm to 400nm (i.e. Violet I light). Blue light is light in the wavelength range 420nm to 490nm. Royal blue is blue light in the wavelength range 440nm to 465nm. Green light is light in the wavelength range 510nm to 580nm. High efficient and/or high quality green light is green light in the wavelength range 520nm to 565nm i.e. “midrange green light”. Red is light in the wavelength range 600nm to 780nm High efficient and/or high quality red light is red light in the wavelength range 610nm to 660nm i.e. “short wavelength-red light”.

Such a lighting arrangement provides an improved performance, especially in terms of less browning, and thereby prolonged lifetime/reliability, of closely arranged components, due to the effect that the local UV/violet/blue LED light intensity is significantly reduced. Especially, polymer components/layers are degraded over time due to high intense UV/violet/blue LED light.

Although an effect of reduced light intensity may be considered as being undesired, such reduction is not present for wavelengths that are longer than those of the UV/violet/blue LED light. Because LEDs with a larger die area are relatively cheaper than LEDs with a smaller die area e.g. in terms of assembly costs, it is desired to use these types of LEDs for these other, longer, wavelength ranges.

By configuring embodiments of the lighting arrangement such that SEI is less than or equal to 80 micrometers, SE2 is greater than or equal to 500 micrometers and R1 is greater than or equal to 20, it is possible to obtain an even higher improvement in reliability and lifetime for the lighting arrangement.

In embodiments, SEI may be less than or equal to 80 micrometers, preferably <70 micrometers, more preferably <60 micrometers, most preferably <50 micrometers such as for example 40 micrometers.

In embodiments, SE2 may be greater than or equal to 400 micrometers, preferably >500 micrometers, more preferably >600 micrometers, most preferably >700 micrometers such as for example 800 micrometers.

In embodiments, R1 may be greater than or equal to 20, preferably >25, more preferably >30, most preferably >35 such as for example 40.

The number of M-LEDs of the plurality of M-LEDs may be X, the number of N-LEDs of the plurality of N-LEDs may be Y and wherein X is greater than or equal to 5 times Y. That is, due to the fact that the size of the M-LEDs are smaller than the size of the N-LEDs, the number of M-LEDs are greater than the number of N-LEDs in order to enable the lighting arrangement to provide sufficient light in the B/V/UV wavelength range.

The plurality of M-LEDs may be homogeneously distributed with a first pitch (Pl) within a first region on the carrier and the plurality of N-LEDs may be homogeneously distributed with a second pitch (P2) within a second region on the carrier. The second region at least partly overlaps the first region and P2 is greater than or equal to 2 times PL In other words, by configuring the lighting arrangement with homogeneous distributions having different pitch of the M-LEDS and the N-LEDs, the performance of the lighting arrangement may be even further improved. It will improve spreading of the B/V/UV light and thus lowering the local intensity of the B/V/UV light.

Each of the M-LEDs may have a first length (LI), a first width (Wl) and a first aspect ratio (ARI) defined by Ll/Wl. Each of the N-LEDs may have a second length (L2), a second width (W2) and a second aspect ratio (AR2) defined by L2/W2, where AR2 is greater than ARI. Due to the size of the M-LEDs and N-LEDs, for the M-LEDs a high aspect ratio is not possible, while this is possible for the N-LEDs Such a configuration is advantageous in that it may simplify electrical connections in terms of a larger distances between anode and cathode pads in the N-LEDs. By using a smaller aspect ratio for the B/V/UV MicroLEDs local intensity of the B/V/UV light is further reduced.

The dies of the M-LEDs may be free from any luminescent material. The N- LEDs may comprise a wavelength converter and the dies of the N-LEDs may be covered by the wavelength converter comprising a luminescent material. Such a configuration provides improved quality of white light due to more light at other wavelength due to phosphor conversion which typically have broader emission peaks than LEDs.

The M-LEDs may comprise (i) one or more B LEDs (emitting the blue light) and (ii) one or more V LEDs (emitting the violet light) and/or one or more UV LEDs (emitting the UV light). That is, in some applications such as lighting arrangements for providing crispy white or disinfection white lighting, both blue light and violet/UV light are needed. High light intensity in all these wavelength ranges have a negative impact on closely arranged components. Therefore, for all these types of light a lower intensity is desired which is obtained by using well distributed M-LEDs for these wavelength ranges.

In embodiments, the M-LEDs may comprise UVA, UVB, UVC, V and/or blue LEDs.

The M-LEDs may comprise one or more B LEDs and the N-LEDs may comprise one or more G LEDs (emitting the green light) and one or more R LEDs (emitting the red light). That is, such a configuration of the lighting arrangement is an RGB architecture that is capable of, e.g., creating (high quality) white light.

The number of G N-LEDs may be greater than or equal to 2 or 3 times the number of R N-LEDs. That is, such a configuration of the lighting arrangement is capable of providing white light with a high efficiency.

The N-LEDs may comprise one or more white phosphor converted LEDs. That is, the N-LEDs may be configured such that the die is covered by a wavelength converter, wherein the wavelength converter comprises a luminescent material, wherein the luminescent material comprises a green-yellow phosphor and a red phosphor, wherein the die emits blue light, and wherein the green-yellow phosphor converts part of the blue light into green-yellow light, and wherein the red phosphor converts the blue light and/or the greenyellow light into red light.

Each N-LED may be neighbored by at least 2 B M-LEDs, preferably at least 3 B M-LEDs. That is, such a configuration of the lighting arrangement provides an optimal color mixing, e.g. for creating high quality white light. Each N-LED may comprise 4 sides, wherein each side is neighbored by at least 1 B M-LED. That is, such a configuration of the lighting arrangement provides an optimal color mixing, e.g. for creating high quality white light.

The plurality of M-LEDs may be connected with a respective anode having an anode surface area (AS Al) and a respective cathode having a cathode surface area, CSA1. The plurality of N-LEDs may be connected with a respective anode having an anode surface area (ASA2) and a respective cathode having a cathode surface area (CSA2). ASA2 may be greater than or equal to 4 times ASA1 and/or CSA2 may be greater than or equal to 4 times CSA1. In other words, the electrodes/electrical tracks are scaled to a suitable configuration.

The plurality of M-LEDs may be connected via a first circuitry and the plurality of N-LEDs may be connected via a second circuitry. The lighting arrangement may comprise a controller configured to individually control the emission of the first light emitted by said plurality of M-LEDs via the first circuitry and the emission of the second light emitted by said plurality of N-LEDs via the second circuitry.

For example, the first circuitry may comprise a first number of parallel arrangements (PAI) and the second circuitry may comprise a second number of parallel arrangements (PA2), or the second circuitry may be a series circuit. PAI is greater than PA2 or the se second circuitry is a series circuit.

In embodiments, the lighting arrangement may comprises a light exit window e.g. an envelope or a plate. The light exit window may be light diffusive / scattering. The light exit window may be a diffuser having a reflectivity R. R may be in a range from 15% to 45%, especially 15% to 35%.

In embodiments, a LED package may comprise the lighting arrangement.

In a second aspect there is provided a lamp or a luminaire comprising the lighting arrangement as summarized above. Such a lamp or luminaire provides corresponding effects and advantages as described above. The lamp may comprise a connector such as a cap to electrically and/or mechanically connect the lamp to a socket of a luminaire. The lamp may also have an antenna which is functionally connected to the controller allowing remote control of the lamp e.g. adjusting the intensity and/or color point/correlated color temperature e.g. using a remote control e.g. a mobile phone. The lamp may also have an envelope enveloping the lighting arrangement. The luminaire may have a mounting means to mount the luminaire to a wall or ceiling. The luminaire may comprise a light exit window such as a translucent plate to exit the arrangement light. BRIEF DESCRIPTION OF THE DRAWINGS

This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing embodiment(s) of the invention.

Fig. la schematically illustrates a top view of a lighting arrangement,

Fig. lb schematically illustrates a cross-sectional view of the lighting arrangement illustrated in figure la,

Fig. 1c schematically illustrates a top view of an N-LED and four M-LEDs,

Fig. Id schematically illustrates anodes and cathodes in an N-LED and in four M-LEDs,

Fig. le schematically illustrates a lighting arrangement connected to a controller via circuitry,

Fig. If schematically illustrates two parallel arrangements of LEDs,

Fig. 1g schematically illustrates a parallel and a serial arrangement of LEDs, and

Fig. 2 schematically illustrates a lamp or a luminaire.

DETAILED DESCRIPTION

As illustrated in figure la and figure lb, a lighting arrangement 100 configured to provide arrangement light comprises a carrier 151. A plurality of first light emitting diodes, M-LEDs, 101 are arranged on the carrier 151, each of the M-LEDs 101 comprising a die 111 having a first surface area, SAI, wherein the SAI has a largest spatial extent, SEI, that is less than or equal to 100 micrometers. A plurality of second light emitting diodes, N-LEDs 102 are arranged on the carrier 151, each of the N-LEDs 102 comprising a die 112 having a second surface area, SA2, wherein the SA2 has a largest spatial extent, SE2, that is greater than or equal to 300 micrometers.

The M-LEDs 101 are configured to emit first light, LG1, having a first emission peak wavelength, I, in a wavelength range of ultraviolet light, UV, violet light, V, and/or blue light, B. The N-LEDs 102 are configured to emit second light, LG2, having a second emission peak wavelength, X2, in a wavelength range of green light, G, and/or red light, R. A ratio, Rl, defined by SA2/SA1 is equal to or larger than 10 and the arrangement light is white light having a correlated color temperature, CCT, in a range from 2000K to 6500K and a color rendering index, CRI, of at least 80.

For example, the M-LEDs 101 may comprise (i) one or more B LEDs and (ii) one or more V LEDs and/or one or more UV LEDs. Also, for example, the M-LEDs 101 may comprise one or more B LEDs and the N-LEDs 102 may comprise one or more G LEDs and one or more R LEDs and, in such examples, the number of G N-LEDs 102 may be greater than or equal to 2 times the number of R N-LEDs 102.

In some embodiments, the N-LEDs 102 comprises one or more white phosphor converted LEDs.

In some embodiments, each N-LED 102 is neighbored by at least 2 B M-LEDs 101, preferably at least 3 B M-LEDs 101.

In some embodiments, and as schematically illustrated in figure 1c, each N- LED 102 may comprise 4 sides, wherein each side is neighbored by at least 1 B M-LED 101.

In some embodiments of the lighting arrangement 100, SEI is less than or equal to 80 micrometers, SE2 is greater than or equal to 500 micrometers and R1 is greater than or equal to 20.

Although the lighting arrangement 100 schematically illustrated in figure la comprises a specific number of LEDs, i.e.16 N-LEDs and 64 M-LEDs, the number of M- LEDs of the plurality of M-LEDs (101) may be X and the number of N-LEDs of the plurality of N-LEDs (102) may be Y and wherein X is greater than or equal to 5 times Y.

As illustrated in figure la, the plurality of M-LEDs 101 may be homogeneously distributed with a first pitch, Pl, within a first region 161 on the carrier 151 and the plurality of N-LEDs 102 may be homogeneously distributed with a second pitch, P2, within a second region 162 on the carrier 151. The second region 162 may at least partly be overlapping the first region 161 and P2 may be greater than or equal to 2 times PL

As illustrated in figure 1c, the M-LEDs 101 and the N-LEDs 102 may have other shapes than the round shape exemplified in figure la. For example, as illustrated in figure 1c where the M-LEDs 101 and the N-LEDs 102 have rectangular shapes. For example, each of the M-LEDs 101 may have a first length, LI, a first width, Wl, and a first aspect ratio, ARI, defined by Ll/Wl. Each of the N-LEDs 102 may have a second length, L2, a second width, W2, and a second aspect ratio, AR2, defined by L2/W2, and AR2 may be greater than ARI.

The dies 111 of the M-LEDs 101 may be free from any luminescent material; and the N-LEDs 102 may comprises a wavelength converter 160 as exemplified in figure lb. The dies 112 of the N-LEDs 102 are thus covered by the wavelength converter 160 comprising a luminescent material.

Turning now to figure Id, in some embodiments, the plurality of M-LEDs 101 may be connected with a respective anode 121 having an anode surface area, ASA1, and a respective cathode 122 having a cathode surface area, CSA1. Similarly, the plurality of N- LEDs 102 may be connected with a respective anode 131 having an anode surface area, ASA2, and a respective cathode 132 having a cathode surface area, CSA2. In some embodiments, ASA2 may be greater than or equal to 4 times ASA1 and/or CSA2 may be greater than or equal to 4 times CSA1.

As schematically illustrated in figure le, the plurality of M-LEDs 101 may be connected via a first circuitry 141 and the plurality of N-LEDs 102 may be connected via a second circuitry 142. The lighting arrangement 100 may comprise a controller 140 configured to individually control the emission of the first light emitted by said plurality of M-LEDs 101 via the first circuitry 141 and the emission of the second light emitted by said plurality of N-LEDs 102 via the second circuitry 142.

For example, as illustrated in figure If, the first circuitry 141 may comprise a first number of parallel arrangements PAI and the second circuitry 142 may comprise a second number of parallel arrangements PA2 or, as illustrated in figure 1g the second circuitry 142 may be a series circuit. In embodiments where both the first and second circuitry 141, 142 are parallel arrangements, then PAI is greater than PA2.

A lamp 200, or a luminaire 200, comprising a lighting arrangement 100 is schematically illustrated in figure 2. Such a lamp 200 or luminaire 200 may comprise a housing 201 and a transparent cover 202.

Claims

CLAIMS:

1. A lighting arrangement (100) configured to provide arrangement light, comprising: a carrier (151); a plurality of first light emitting diodes, M-LEDs, (101) arranged on said carrier (151), each of the M-LEDs (101) comprising a die (111) having a first surface area, SAI, wherein the SAI has a largest spatial extent, SEI, that is less than or equal to 100 micrometers; and a plurality of second light emitting diodes, N-LEDs (102) arranged on said carrier (151), each of the N-LEDs (102) comprising a die (112) having a second surface area, SA2, wherein the SA2 has a largest spatial extent, SE2, that is greater than or equal to 300 micrometers; wherein the M-LEDs (101) are configured to emit first light, LG1, having a first emission peak wavelength, I, in a wavelength range 100-380 nm of ultraviolet light, UV, 380-420 nm of violet light, V, and/or 420-490 nm of blue light, B; wherein the N-LEDs (102) are configured to emit second light, LG2, having a second emission peak wavelength, X2, in a wavelength range 510-580 nm of green light, G, and/or 610-680 nm of red light, R; wherein the number of M-LEDs of the plurality of M-LEDs (101) is X; the number of N-LEDs of the plurality of N-LEDs (102) is Y; and X is greater than or equal to 5 times Y, and wherein a ratio, Rl, defined by SA2/SA1 is equal to or larger than 10; and wherein said arrangement light is white light having a correlated color temperature, CCT, in a range from 2000K to 6500K and a color rendering index, CRI, of at least 80.

2. The lighting arrangement (100) according to claim 1, wherein:

SEI is less than or equal to 80 micrometers;

SE2 is greater than or equal to 500 micrometers; and Rl is greater than or equal to 20.

3. The lighting arrangement (100) according to any one of the preceding claims, wherein: the plurality of M-LEDs (101) are homogeneously distributed with a first pitch, Pl, within a first region (161) on the carrier (151); the plurality of N-LEDs (102) are homogeneously distributed with a second pitch, P2, within a second region (162) on the carrier (151), the second region (162) at least partly overlapping the first region (161); and wherein P2 is greater than or equal to 2 times Pl.

4. The lighting arrangement (100) according to any one of the preceding claims, wherein: each of the M-LEDs (101) has a first length, LI, a first width, Wl, and a first aspect ratio, ARI, defined by LI AVI; each of the N-LEDs (102) has a second length, L2, a second width, W2, and a second aspect ratio, AR2, defined by L2AV2; and

AR2 is greater than ARI .

5. The lighting arrangement (100) according to any one of the preceding claims, wherein: the dies (111) of the M-LEDs (101) are free from any luminescent material; and the N-LEDs (102) comprises a wavelength converter (160), and the dies (112) of the N-LEDs (102) are covered by the wavelength converter (160) comprising a luminescent material.

6. The lighting arrangement (100) according to any one of the preceding claims, wherein: the M-LEDs (101) comprises (i) one or more B LEDs and (ii) one or more V LEDs and/or one or more UV LEDs.

7. The lighting arrangement (100) according to any one of the preceding claims, wherein: - the M-LEDs (101) comprises one or more B LEDs; the N-LEDs (102) comprises one or more G LEDs and one or more R LEDs.

8. The lighting arrangement (100) according to claim 7, wherein: the number of G N-LEDs (102) is greater than or equal to 2 times the number of R N-LEDs (102).

9. The lighting arrangement (100) according to any one of the preceding claims, wherein the N-LEDs (102) comprises one or more white phosphor converted LEDs.

10. The lighting arrangement (100) according to any one of the preceding claims, wherein each N-LED (102) is neighbored by at least 2 B M-LEDs (101), preferably at least 3 B M-LEDs (101).

11. The lighting arrangement (100) according to any one of the preceding claims, wherein each N-LED (102) comprises 4 sides, wherein each side is neighbored by at least 1 B M-LED (lOl).

12. The lighting arrangement (100) according to any one of the preceding claims, wherein: the plurality of M-LEDs (101) are connected with a respective anode (121) having an anode surface area, ASA1, and a respective cathode (122) having a cathode surface area, CSA1; the plurality of N-LEDs (102) are connected with a respective anode (131) having an anode surface area, ASA2, and a respective cathode (132) having a cathode surface area, CSA2; and

ASA2 is greater than or equal to 4 times ASA1 and/or CSA2 is greater than or equal to 4 times CSA1.

13. The lighting arrangement (100) according to any one of the preceding claims, wherein: the plurality of M-LEDs (101) are connected via a first circuitry (141), preferably the first circuitry (141) comprising a first number of parallel arrangements, PAI; the plurality of N-LEDs (102) are connected via a second circuitry (122), preferably the second circuitry (142) comprising a second number of parallel arrangements, PA2, PAI being greater than PA2, or the second circuitry (142) being a series circuit; and wherein: the lighting arrangement (100) comprises a controller (140) configured to individually control the emission of the first light emitted by said plurality of M-LEDs (101) via the first circuitry (141) and the emission of the second light emitted by said plurality of N-LEDs (102) via the second circuitry (142).

14. A lamp (200) or a luminaire (300) comprising the lighting arrangement (100) according to any one of the preceding claims.