Sub-pixelated pixels for emission of polychromatic light

Abstract

The present invention relates to a pixel for emitting polychromatic light, the pixel comprising a base member and a plurality of light emitting elements. The light emitting elements each include an epitaxially grown semiconductor layer stack having an active region and are arranged on the base member spaced apart from each other. The light emitting elements are individually addressable via the base member, and at least a portion of the light emitting elements includes a similar epitaxially grown stack of semiconductor layers. At least a portion of the light emitting elements is configured to emit light of a first wavelength range when a first current is applied to the at least a portion of the light emitting elements, and is configured to emit light of a second wavelength range when a second current is applied to the at least a portion of the light emitting elements, the first wavelength range and the second wavelength range are not overlapped.

Description

[0001] This application claims the priority of German patent application DE 10 2023 101296.7, filed on January 19, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to a sub-pixelated pixel for emitting multi-color light and a method of operating the pixel. Background Art

[0003] μ-LEDs for augmented reality (AR) applications require a minimum emitting area, e.g. <50 μm 2 , efficient light outcoupling from μ-LEDs and high quantum efficiency of red (R), green (G) and blue (B) light to provide, for example, RGB pixels.

[0004] While μ-LEDs configured to emit green and blue light are typically fabricated from indium gallium nitride (InGaN) material systems, μ-LEDs configured to emit red light are typically fabricated from indium gallium aluminum phosphide (InGaAlP) material systems. However, when the LED size is reduced, InGaAlP undergoes high non-radiative surface recombination, resulting in low efficiency, particularly for this color. Another approach for red-emitting components is to increase the indium (In) content in the InGaN material system, however, this is accompanied by an increase in strain within the material, resulting in a large current-induced blue shift, and therefore, when the brightness of the component is increased, the emitted light deviates from the red. Although elastic relaxation can lead to red emission stabilization to offset this blue shift with the help of, for example, micro / nanorod growth, nanofin structures and / or porous substrates, these methods have problems with manufacturing instability and low efficiency of the resulting devices. In addition, all of these technologies are limited by monochrome imager panels, which means that μ-LEDs emitting red, green and blue need to be manufactured on separate wafer substrates.

[0005] In summary, RGB-based AR μ-LED imagers are difficult to implement due to fundamental materials issues, which are most evident for components configured to emit red light.

[0006] It is therefore an object of the present application to provide a small pixel, in particular an RGB pixel, and a method for operating the pixel, which counteracts at least one of the aforementioned problems. Summary of the Invention

[0007] This and other objects are solved by the subject matter of the independent claims. Features and further aspects of the proposed principle are outlined in the dependent claims.

[0008] The core of the present invention is to sub-pixelize already small pixels in the μ-range for emitting multi-color light, wherein at least a portion of the light-emitting elements associated with each sub-pixel includes a similar epitaxially grown semiconductor layer stack, which is configured to emit light of two different wavelength ranges (for example, light in the red spectrum and light in the green spectrum) when two different currents are applied thereto. When the lower current of the two currents is applied for emitting light of the first wavelength range (for example, light in the red spectrum), due to the lower current, the brightness of the light emitted by each light-emitting element is of course lower than when the higher current of the two currents is applied for emitting light of the second wavelength range (for example, light in the green spectrum). However, in order to provide similar brightness of the overall pixel for each of the two different wavelength ranges (for example, light in the red spectrum and light in the green spectrum), sub-pixelization can be used in the following form: the lower current of the two currents for emitting light of the first wavelength range can be applied to more light-emitting elements than the higher current of the two currents for emitting light of the second wavelength range.

[0009] In particular, light-emitting elements comprising similar epitaxially grown semiconductor layer stacks can include InGaN, a material system with a relatively high indium content. Therefore, the inventors exploited the recognized problem that highly strained material systems experience an increasing blue shift as the current applied to a light-emitting element comprising such a material increases, to produce light in different wavelength ranges using the same material system. Therefore, rather than providing relaxation of high-indium-content InGaN to stabilize red light with increasing current, the inventors aimed to do the exact opposite: provide highly strained, high-indium-content InGaN light-emitting elements. Highly strained InGaN light-emitting elements emit light in the red spectrum, but with low intensity, when a low current is applied. Simultaneously, highly strained InGaN light-emitting elements emit light in the green spectrum with higher intensity when a high current is applied. To achieve the same intensity for both red and green light, either a lower current needs to be applied to more light-emitting elements, or a higher current needs to be applied to fewer light-emitting elements. Consequently, subpixelation can be used, as the current required for the desired light intensity in the corresponding wavelength range can be applied to the desired number of light-emitting elements in a pixel.

[0010] According to one aspect, a pixel for emitting polychromatic light comprises a base member and a plurality of light-emitting elements, also referred to as sub-pixels. The plurality of light-emitting elements each comprises an epitaxially grown semiconductor layer stack having an active region, wherein the light-emitting elements are arranged on the base member spaced apart from each other. In addition, the light-emitting elements are individually addressable via the base member, and at least a portion of the light-emitting elements comprise similar epitaxially grown semiconductor layer stacks. In particular, at least a portion of the light-emitting elements may be substantially identical. In addition, at least a portion of the light-emitting elements is configured to emit light of a first wavelength range when a first current is applied to at least a portion of the light-emitting elements, and is configured to emit light of a second wavelength range when a second current is applied to at least a portion of the light-emitting elements, wherein the first wavelength range and the second wavelength range do not overlap.

[0011] According to some aspects, at least a portion of the light-emitting elements are configured to emit light in a red spectrum when a first current is applied to at least a portion of the light-emitting elements, and to emit light in a green spectrum when a second current is applied to at least a portion of the light-emitting elements. Thus, the second current can be, for example, at least 2.5 times, at least 5 times, or at least 10 times higher than the first current.

[0012] According to some aspects, at least a portion of the light-emitting elements are configured to emit light in a third wavelength range when a third current is applied to at least a portion of the light-emitting elements, wherein the first wavelength range, the second wavelength range, and the third wavelength range do not overlap. In particular, the third wavelength range can correspond to light in the blue spectrum. In particular, the third current can be higher than the first current and the second current, for example, at least 2.5 times, at least 5 times, or at least 10 times higher than the second current, and / or at least 25 times, at least 50 times, or at least 100 times higher than the first current.

[0013] In particular, for a light-emitting element configured to emit light of a first wavelength range when a first current is applied thereto, further configured to emit light of a second wavelength range when a second current is applied thereto, and further configured to emit light of a third wavelength range when a third current is applied thereto, wherein the first wavelength range, the second wavelength range, and the third wavelength range correspond, for example, to light of a red spectrum, light of a green spectrum, and light of a blue spectrum, all light-emitting elements can be substantially identical. Thus, at least a portion of the light-emitting elements can be associated with all of the plurality of light-emitting elements of a pixel. This can have the following advantages: substantially identical light-emitting elements manufactured on the same wafer can be used, and the light-emitting elements can be transferred to the base member using the same transfer process.

[0014] According to some aspects, at least one of the light-emitting elements, and in particular one of the light-emitting elements that is not at least a portion of the light-emitting elements, is configured to emit light in a third wavelength range when a third current is applied thereto, wherein the first wavelength range, the second wavelength range, and the third wavelength range do not overlap. In particular, the third wavelength range may correspond to light in the blue spectrum. In particular, at least one of the light-emitting elements may include a semiconductor layer stack that is epitaxially grown differently than at least a portion of the light-emitting elements, for example, including a different material system and / or a different material composition and / or a different doping of the active region. In particular, at least one of the light-emitting elements may include a lower strain, in particular a lower strain active region, than at least a portion of the light-emitting elements.

[0015] According to some aspects, the pixel comprises less than 50 μm when viewed on top of the pixel. 2 For example, a pixel may include a projection area of less than 50 μm 2 The shape / outer contour of the pixel can be a square, rectangle, hexagon, any other polygon or circle with an area of ​​about 100 μm. In the case of a square, the pixel can, for example, have an edge length of less than 7 μm and can therefore have a size comparable to a μ-LED. Thus, the pixel can already be a small component, which can then be sub-pixelated with even smaller light-emitting elements.

[0016] According to some aspects, the light emitting element comprises less than 5 μm when viewed on top of the pixel. 2 For example, the light emitting element may include a projection area of less than 5 μm 2 The shape / outer contour of the base member may be a square, rectangle, hexagon, any other polygon or circle of an area of ​​the pixel. In the case of a square, the light-emitting element may, for example, include an edge length of less than 2.5 μm. Thus, within the already small projected area of the pixel, a plurality of even smaller light-emitting elements can be arranged on the base member to form sub-pixels of the pixel.

[0017] According to some aspects, the base member is a CMOS backplane. The light-emitting elements can be electrically coupled to the CMOS backplane such that all light-emitting elements are individually addressable via the submicron structure of the CMOS backplane. This allows for individual selection of the number of light-emitting elements to which the first current, the second current, or an optional third current is applied to emit light of a desired intensity within the corresponding wavelength range.

[0018] According to some aspects, at least a portion of the light-emitting element includes a highly strained material, and in particular, a highly strained quantum well (QW) structure within the corresponding active region. Due to the highly strained quantum well structure, the light emitted by the light-emitting element undergoes a significant current-induced blue shift, and thus, when the current applied to the light-emitting element is increased, the light emitted from the light-emitting element deviates from the red. However, this effect is actively used by the inventors to provide emission of light having different wavelength ranges using the same light-emitting element. Therefore, measures to provide elastic relaxation in the quantum well structure may be undesirable.

[0019] According to some aspects, at least a portion of the light-emitting element includes a semiconductor layer stack of InGaN. InGaN can be a particularly suitable material system for light-emitting elements configured to emit green and blue light. When the indium content of the InGaN is increased, the material system is also configured to emit red light. Increasing the indium content of the InGaN material system leads to high strain within the quantum well structure of the light-emitting element, which is generally an undesirable effect. However, in this case, the inventors actively exploited this generally undesirable effect, enabling the same light-emitting element to emit light in different wavelength ranges by applying different currents to the same light-emitting element. Therefore, in the active region of the light-emitting element, the indium content can be, for example, greater than 30%, and even more particularly, greater than 35%. In particular, the quantum well structure responsible for light emission should have an In content greater than 35%. This indium content will allow the emission of red and green light, and in the case of sufficiently high strain, also allow the emission of blue light for corresponding high currents. Strain-induced plastic relaxation, which can reduce the efficiency of the light-emitting element and reduce the current-induced blue shift of the light emitted by the light-emitting element and may therefore be undesirable, can be minimized by reducing the number of QWs and their thickness. Nanostructuring technology below the QW can also support stability against plastic relaxation.

[0020] According to some aspects, the pixel further comprises an optical element / coupling structure arranged on top of the plurality of light-emitting elements. The optical element can be, for example, a lens or a μ-lens array and helps to provide uniformly distributed multi-color light emitted from the pixel. With the aid of the optical element, it is possible, for example, to define the emission area and the emission angle of the light emitted from the pixel. The optical element can include sub-elements, where each sub-element corresponds to a light-emitting element, or the optical element can cover the pixel as a single component.

[0021] According to some aspects, a pixel is configured to emit light of a first wavelength range when a first current is applied to at least a portion of the light-emitting elements, and wherein the pixel is configured to emit light of a second wavelength range with substantially similar brightness when a second current is applied to a sub-portion of at least a portion of the light-emitting elements. In order to achieve the same brightness for the light of the first wavelength range and the second wavelength range, the first current needs to be applied to more light-emitting elements or the second current needs to be applied to fewer light-emitting elements. Therefore, sub-pixelation can be used because the corresponding current can be applied to the required number of light-emitting elements of the pixel for the required light intensity of the corresponding wavelength range.

[0022] According to some aspects, the pixel is configured to emit light of a third wavelength range having a brightness substantially similar to that of light of the first wavelength range and the second wavelength range when a third current is applied to at least one of the light-emitting elements, wherein the first wavelength range, the second wavelength range, and the third wavelength range do not overlap. In order to achieve the same brightness for the light of the first wavelength range, the second wavelength range, and the third wavelength range, the first current and the second current need to be applied to more light-emitting elements, or the third current needs to be applied to fewer light-emitting elements. Therefore, sub-pixelation can be used because the corresponding current can be applied to the required number of light-emitting elements of the pixel for the required light intensity of the corresponding wavelength range.

[0023] According to some aspects, the pixel is configured to emit polychromatic light, and in particular white light, by mixing light of a first wavelength range, a second wavelength range, and a third wavelength range. Possible methods of mixing light of the first wavelength range, the second wavelength range, and the third wavelength range, for example, to provide white light, will be described later in this application.

[0024] According to yet another aspect, an optoelectronic device is provided, comprising a plurality of pixels according to at least some aspects of the proposed principles. The pixels are arranged adjacent to one another, for example, on a carrier substrate or backplane. The optoelectronic device may be, for example, a display, a lamp, or the like configured to provide a plurality of pixels of light having a desired wavelength range.

[0025] According to yet another aspect, there is provided a method of operating a pixel according to at least some aspects of the proposed principles. The method comprises the following steps:

[0026] driving at least a portion of the light emitting elements with a first current so that at least a portion of the light emitting elements emit light in a first wavelength range; and

[0027] A sub-portion of at least a portion of the light emitting elements is driven with a second current so that the sub-portion of at least a portion of the light emitting elements emits light in a second wavelength range.

[0028] According to some aspects, the method further comprises the step of: driving at least one of the light-emitting elements with a third current such that the at least one light-emitting element emits light in a third wavelength range. Thus, the at least one light-emitting element may be a light-emitting element substantially similar to all other light-emitting elements, or may be a light-emitting element different from at least some of the light-emitting elements.

[0029] According to some aspects, the steps of driving at least a portion of the light-emitting elements, driving a sub-portion of at least a portion of the light-emitting elements, and driving at least one light-emitting element are performed sequentially to mix light of the first wavelength range, the second wavelength range, and the third wavelength range into light of a fourth wavelength range. Thus, the fourth wavelength range can, for example, be related to the spectrum of white light, but can also be related to light of any other desired color provided by the pixel.

[0030] According to some aspects, in order to mix light in a fifth wavelength range that is different from the fourth wavelength range, a first current is used to drive a different number of light-emitting elements than that used to mix the light in the fourth wavelength range, and / or a second current is used to drive a different number of light-emitting elements than that used to mix the light in the fourth wavelength range, and / or a third current is used to drive a different number of light-emitting elements than that used to mix the light in the fourth wavelength range.

[0031] According to some aspects, the step of driving at least a portion of the light-emitting elements and / or the step of driving a sub-portion of at least a portion of the light-emitting elements and / or the step of driving at least one light-emitting element includes driving the corresponding light-emitting element using a pulse width modulated current. If the pulses are emitted sufficiently quickly one after another, a single pulse of light of the first wavelength range and / or the second wavelength range and / or the third wavelength range can produce, at least for the human eye, a mixed light of a fourth wavelength range. Thus, the mixed light of the fourth wavelength range can, for example, be related to the spectrum of white light, but can also be related to light of any other desired color to be provided by the pixel.

[0032] According to some aspects, in order to mix light of a fifth wavelength range that is different from the fourth wavelength range, at least a portion of the light-emitting elements are driven using a first current having a pulse length different from that used to mix the light of the fourth wavelength range, and / or a sub-portion of at least a portion of the light-emitting elements are driven using a second current having a pulse length different from that used to mix the light of the fourth wavelength range, and / or at least one light-emitting element is driven using a third current having a pulse length different from that used to mix the light of the fourth wavelength range.

[0033] Advantages of pixels according to at least some aspects of the proposed principles may be, for example, reduced cost and complexity, since the light-emitting elements need only be transferred to the base member at the wafer level once in the case where the light-emitting elements are configured to emit light in the first wavelength range, the second wavelength range and the third wavelength range, or only need to be transferred to the base member at the wafer level twice in the case where the light-emitting elements are configured to emit light in the first wavelength range and the second wavelength range and a separate light-emitting element is configured to emit light in the third wavelength range. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Further aspects and embodiments according to the proposed principles will become apparent with respect to the various embodiments and examples described in detail with reference to the accompanying drawings, in which:

[0035] Figure 1A and Figure 1B each showing a top view of an embodiment of a pixel according to some aspects of the proposed principles;

[0036] Figure 2A and Figure 2B each showing a top view of an embodiment of an optoelectronic device according to some aspects of the proposed principles; and

[0037] Figures 3A to 3C Each shows a top view of a possible operating state of a pixel according to some aspects of the proposed principles. DETAILED DESCRIPTION

[0038] The following embodiments and examples disclose various aspects and combinations thereof according to the proposed principles. The embodiments and examples are not always drawn to scale. Similarly, different elements may be shown in enlarged or reduced sizes to emphasize various aspects. It is obvious that various aspects of the embodiments and examples shown in the accompanying drawings can be combined with each other without difficulty, and this does not conflict with the principles of the present invention. Some aspects show regular structures or forms. It should be noted that in practice, slight differences and deviations from the ideal form may occur, but this does not conflict with the inventive concept.

[0039] Furthermore, the various figures and aspects are not necessarily shown to the correct scale, nor are the proportions between the various elements necessarily substantially correct. Some aspects are highlighted by enlarging them. However, terms such as "above," "above," "below," "below," "larger," "smaller," etc., are accurately represented with respect to the elements in the figures. Therefore, such relationships between the elements can be inferred based on the figures.

[0040] Figure 1A and Figure 1BEach shows a top view of an embodiment of a pixel 1 according to some aspects of the proposed principles. The pixel 1 comprises a base member 2, on which a plurality of light-emitting elements 3 are arranged spaced apart from each other. The base member 2 may, for example, be a CMOS backplane comprising submicron structures via which the light-emitting elements 3 can be individually addressed. In the embodiment shown, the base member 2 comprises a projected area 5 having a hexagonal shape, however any other shape such as, for example, a square, polygonal or circular is possible. On the other hand, in the embodiment shown, the light-emitting element 3 comprises a projected area 6 having a square shape, however any other shape such as, for example, a hexagonal, polygonal or circular is possible. The shape of the light-emitting elements may, for example, depend on the manufacture of the light-emitting elements.

[0041] The light-emitting elements 3 are arranged on the base member 2 in rows arranged one above the other and at a substantially similar pitch to any adjacent light-emitting elements, so as to fill the projection area 5 with the light-emitting elements 3 in the most efficient manner. However, any other arrangement on the base member 2 is possible, as this may occur due to a specific transfer process or manufacturing method. At the same time, the arrangement of the light-emitting elements 3 can affect the light-emitting characteristics of the pixel 1 and can therefore be selected in a desired manner.

[0042] At least a portion 4 of the light-emitting elements 3 (indicated by hatching) includes a similar epitaxially grown semiconductor layer stack, particularly a semiconductor layer stack of InGaN having an indium content of at least 30% within the active region of the light-emitting element. This indium content results in high strain in the light-emitting element, which the inventors exploited because this high strain in the light-emitting element, and particularly in the active region, causes a high current-induced shift in the emission wavelength of the light-emitting element. For this reason, at least a portion 4 of the light-emitting elements 3 is configured to emit light in a first wavelength range when a first current is applied to the at least a portion 4 of the light-emitting elements 3, and is configured to emit light in a second wavelength range when a second current is applied to the at least a portion 4 of the light-emitting elements 3, wherein the first wavelength range and the second wavelength range do not overlap. By applying two different currents to the same light-emitting element, the same light-emitting element is configured to emit light in different wavelength ranges.

[0043] In the embodiment shown, the light-emitting element 3 (not hatched) in the center of the pixel is configured to emit light of a third wavelength range when a third current is applied thereto. Thus, the light-emitting element 3 in the center can be substantially the same as the other light-emitting elements, and emission of the third wavelength range can be provided by applying an even higher third current to the light-emitting element 3 in the center, causing an even higher shift in the emission wavelength, or the light-emitting element 3 in the center can be different from the other light-emitting elements and therefore configured to emit a different third wavelength range. In the embodiment shown, only one light-emitting element is configured to emit light of the third wavelength range, and in particular, the light-emitting element is a light-emitting element that is different from the other light-emitting elements. However, the number one should be understood to be merely exemplary, and more than one light-emitting element 3 can be configured to emit the third wavelength range.

[0044] Apart from Figure 1A In addition, Figure 1B Also shown is a pixel 1 comprising an optical element 7 arranged on top of the light emitting element 3. In particular, the optical element 7 is a lens covering the light emitting element 3, the lens being configured to provide an evenly distributed multi-colored light emitted from the pixel 1.

[0045] Figure 2A and Figure 2B Each shows a top view of an embodiment of an optoelectronic device 10 according to some aspects of the proposed principles. The optoelectronic device 10 exemplarily comprises four pixels 1 arranged adjacent to each other, however the number 4 is to be understood as merely exemplary and any other number of pixels 1 may be arranged adjacent to each other in relation to the application of the optoelectronic device 10. Figure 2A In addition, Figure 2B Also shown are each optical element 7 arranged on top of a pixel 1. The optical elements 7 are, for example, in the form of a μ-lens array, each optical element 7 being a lens covering one of the pixels 1 and each lens being configured to provide uniformly distributed polychromatic light emitted from the pixel 1.

[0046] Figures 3A to 3C Each shows a top view of a possible operating state of a pixel according to some aspects of the proposed principles. Figure 3A An operating state is shown in which a first current I1 is applied to at least a portion 4 of the light emitting elements 3 to emit light in a first wavelength range. Figure 3B The operating state is shown in which a subsection 4a of at least a portion 4 of the light emitting element 3 is applied with a second current I2 to emit light in a second wavelength range. Figure 3C The central light emitting element 3 is shown in an operating state where a third current I3 is applied to emit light in a third wavelength range. Thus, the first wavelength range is particularly relevant to light in the red spectrum, the second wavelength range is particularly relevant to light in the green spectrum, and the third wavelength range is particularly relevant to light in the blue spectrum.

[0047] Since the first current I1 for emitting light in the first wavelength range is relatively low, all light-emitting elements in at least one portion 4 must be applied with the first current I1 to achieve an overall brightness similar to that of the second current for emitting light in the second wavelength range and the third current for emitting light in the third wavelength range. As shown in the figure, only a sub-portion 4a in at least one portion 4 is applied with the second current to achieve an overall brightness similar to that of the first current, and an even smaller portion 8, i.e., one, of the light-emitting elements 3 is applied with the third current to achieve an overall brightness similar to that of the first and second currents.

[0048] In terms of the red, green and blue spectrum and therefore pixels operating as RGB pixels this could mean:

[0049] Red operation: operating all light-emitting elements 3 in at least one portion 4 at a low current I1. This results in a low brightness of each light-emitting element, but a high cumulative brightness of the pixel 1.

[0050] Green operation: operating a subsection 4a of at least a portion 4 of the light-emitting elements 3 at a medium current I2 while switching off all other light-emitting elements 3 in at least a portion 4. This results in a medium brightness per light-emitting element, but a high cumulative brightness of the pixel 1.

[0051] - Blue operation: an even smaller portion 8 of the luminous elements 3, ie one luminous element, is operated at the third current I3, while switching off the luminous elements 3 in at least one portion 4. This results in a high brightness of each luminous element and of the pixel 1.

[0052] For such pixels, in particular RGB pixels, white light or any other color can be produced by mixing light of different wavelength ranges. Thus, light can be mixed by means of the pulse width modulation principle, which means that the amount / brightness of light of different wavelength ranges emitted by the pixel is controlled by means of the pulse length of the corresponding wavelength. Therefore, within a time that the eye cannot distinguish, the three wavelength ranges are emitted one after another in the desired ratio to obtain light of the desired color. Another way to mix light of the desired color can be to address a specific number of light-emitting elements 3 each with a corresponding current to control the brightness of the light emitted by each wavelength range individually via the number of light-emitting elements being operated. Then, within a time that the eye cannot distinguish, the light of the corresponding wavelength ranges is emitted again one after another to obtain mixed light of the desired color.

[0053] Reference Signs List

[0054] 1 pixel

[0055] 2 base components

[0056] 3 Light-emitting elements

[0057] 4 parts

[0058] Subpart 4a

[0059] 5 Projection area

[0060] 6 Projection area

[0061] 7 Optical Elements

[0062] 8 parts

[0063] I Current

Claims

1. A pixel (1) for emitting polychromatic light, the pixel comprising: base member (2); as well as a plurality of light-emitting elements (3), each of which comprises an epitaxially grown semiconductor layer stack having an active region and is arranged on the base member (2) at a distance from one another; wherein the light emitting elements (3) are individually addressable via the base member (2); wherein at least a portion (4) of the light emitting element (3) comprises a stack of similar epitaxially grown semiconductor layers; and wherein the at least a portion (4) of the light-emitting elements (3) is configured to emit light in a first wavelength range when a first current (I1) is applied to the at least a portion (4) of the light-emitting elements (3), and is configured to emit light in a second wavelength range when a second current (I2) is applied to the at least a portion (4) of the light-emitting elements (3), wherein the first wavelength range and the second wavelength range do not overlap.

2. The pixel according to claim 1, wherein The at least one portion (4) of the light-emitting elements (3) is configured to emit light in a red spectrum when the first current (I1) is applied to the at least one portion (4) of the light-emitting elements (3), and to emit light in a green spectrum when the second current (I2) is applied to the at least one portion (4) of the light-emitting elements (3).

3. The pixel according to claim 1 or 2, wherein: At least one of the light emitting elements (3) is configured to emit light in a blue spectrum when a third current (I3) is applied to the at least one light emitting element (3).

4. A pixel according to any one of the preceding claims, wherein When viewed on top of the pixel (1), the pixel (1) comprises less than 50 μm 2 The projection area (5).

5. A pixel according to any one of the preceding claims, wherein When viewed on top of the pixel, the light emitting element (3) comprises less than 5 μm 2 The projection area (6).

6. A pixel according to any one of the preceding claims, wherein The base component (2) is a CMOS backplane.

7. A pixel according to any one of the preceding claims, wherein The at least one portion (4) of the light emitting element (3) comprises a high strain material, and in particular a high strain quantum well structure in a corresponding active region.

8. A pixel according to any one of the preceding claims, wherein: The at least one portion (4) of the light emitting element (3) comprises a semiconductor layer stack of InGaN.

9. The pixel according to claim 8, wherein: The at least one portion (4) of the light emitting element (3) comprises an indium content greater than 30%, and in particular comprises a quantum well structure within the corresponding active region having an indium content greater than 30%.

10. The pixel according to any of the preceding claims, further comprising an optical element (7) arranged on top of the plurality of light emitting elements (3).

11. A pixel according to any one of the preceding claims, wherein The pixel (1) is configured to emit light of the first wavelength range when the first current (I1) is applied to the at least part (4) of the light-emitting elements (3), and wherein the pixel (1) is configured to emit light of the second wavelength range with substantially similar brightness when the second current (I2) is applied to a sub-portion (4a) of the at least part (4) of the light-emitting elements (3).

12. The pixel according to claim 11, wherein The pixel (1) is configured to emit light in a third wavelength range having a brightness substantially similar to that of light in the first wavelength range and the second wavelength range when the third current (I3) is applied to at least one of the light-emitting elements (3), wherein the first wavelength range, the second wavelength range, and the third wavelength range do not overlap.

13. The pixel according to claim 12, wherein: The pixel (1) is configured to emit white light by mixing light of the first wavelength range, the second wavelength range, and the third wavelength range.

14. An optoelectronic device (10) comprising a plurality of pixels (1) according to any one of the preceding claims arranged adjacent to one another.

15. A method of operating a pixel (1) according to any one of claims 1 to 14, the method comprising the steps of: driving the at least one portion (4) of the light-emitting element (3) with a first current (I1), so that the at least one portion (4) of the light-emitting element (3) emits light in the first wavelength range; as well as A subsection (4a) of the at least one portion (4) of the light-emitting element (3) is driven by a second current (I2), so that the subsection (4a) of the light-emitting element (3) emits light in the second wavelength range.

16. The method according to claim 15, further comprising the steps of: At least one of the light-emitting elements (3) is driven by a third current (I3), so that the at least one light-emitting element (3) emits light in a third wavelength range.

17. The method according to claim 16, wherein The steps of driving the at least one portion (4) of the light-emitting elements (3), driving the sub-portion (4a) of the at least one portion (4) of the light-emitting elements (3), and driving the at least one light-emitting element (3) are sequentially performed to mix the light of the first wavelength range, the second wavelength range, and the third wavelength range into light of a fourth wavelength range.

18. The method according to claim 17, wherein In order to mix light of a fifth wavelength range that is different from the fourth wavelength range, the first current (I1) is used to drive a different number of light-emitting elements (3) than that used to mix the light of the fourth wavelength range, and / or the second current (I2) is used to drive a different number of light-emitting elements than that used to mix the light of the fourth wavelength range, and / or the third current (I3) is used to drive a different number of light-emitting elements than that used to mix the light of the fourth wavelength range.

19. The method according to any one of claims 15 to 18, wherein The step of driving the at least one portion (4) of the light-emitting elements (3) and / or the step of driving the sub-portion (4a) of the at least one portion (4) of the light-emitting elements (3) and / or the step of driving the at least one light-emitting element (3) comprises driving the corresponding light-emitting element using a pulse width modulated current.

20. The method according to claim 19, wherein In order to mix light of a fifth wavelength range different from the fourth wavelength range, the at least one portion (4) of the light-emitting elements (3) is driven by the first current (I1) having a pulse length different from that used for mixing the light of the fourth wavelength range, and / or the sub-portion (4a) of the at least one portion (4) of the light-emitting elements (3) is driven by the second current (I2) having a pulse length different from that used for mixing the light of the fourth wavelength range, and / or the at least one light-emitting element (3) is driven by the third current (I3) having a pulse length different from that used for mixing the light of the fourth wavelength range.

21. The method according to any one of claims 15 to 20, wherein The second current (I2) is at least 5 times higher than the first current (I1).

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