Red-Green-Blue Monolithic Integrated High-Purity Microlight Emitting Diode Display Device

Abstract

A color conversion resonator system (600) comprising a first partially reflective region (120) that transmits light (742) at a first wavelength and reflects light (744) at a second wavelength; a second partially reflective region (116) that at least partially transmits light at the first and second wavelengths and reflects light (746) at a third wavelength; a third partially reflective region (112) that at least partially reflects light at the third wavelength; and a first color conversion resonator cavity (118) that receives input light having a first wavelength through the first partially reflective region and converts at least a portion of the light at the first wavelength to light at a second wavelength, wherein the first color conversion resonator cavity is configured such that the second wavelength resonates within the first color conversion resonator cavity and the resonated light having the second wavelength is output through the second partially reflective region. and a second color conversion resonator cavity (114) that receives input light comprising a second wavelength through a second partially reflective region and converts at least a portion of the second wavelength into light of a third wavelength, wherein the second color conversion resonator cavity is configured such that the third wavelength resonates within the second color conversion resonator cavity and the resonated light having the third wavelength is output through the third partially reflective region, wherein the first and second resonator cavities are configured to provide partial overlapping, non-overlapping, and overlapping portions, thereby defining first and second light emitting surfaces, respectively, wherein the first light emitting surface provides resonated light at the second wavelength and the second light emitting surface provides resonated light at the third wavelength.

Description

[Technical Field]

[0001] The present invention relates to a light-emitting diode structure and a method for forming a light-emitting diode structure. More specifically, but not limited to, the present invention relates to a vertically integrated color conversion resonator system. [Background technology]

[0002] It is known that a pump-source light-emitting diode (LED) is used to provide input light, and a color conversion material is used to convert such input light into light of a desired wavelength, thereby generating a wavelength of a desired main peak wavelength. Such color conversion materials can be, for example, phosphor materials or quantum dots (QDs). Of particular importance is the generation of light having wavelengths corresponding to red, green, and blue light. The emission of such colors is important in display applications.

[0003] It is known that red, green, and blue light can be provided from a single wafer of monolithically grown light-emitting diode devices that generate light of a specific wavelength (usually blue light) by using a QD material for downconverting the light. Similarly, stacked devices can be created by stacking red, green, and blue light-emitting structures containing quantum wells (QWs) on top of each other. In such devices, the top QW lights up at low current levels, and the middle and bottom QWs are sequentially lit by increasing the current level.

[0004] However, QD materials typically have a load capacity of 0.2 W / cm². 2Because it degrades easily above a certain input power, it cannot be immediately used for micro-LED display applications. Furthermore, when QDs are used as color conversion materials, the thickness of the QD material layer is typically at least 20 μm to completely absorb the input light. Therefore, the thickness of the QD material required to provide sufficient conversion of light wavelengths is greater than that suitable to provide the pixel size and pitch required in high-resolution micro-LED arrays. Moreover, typical color conversion materials such as QDs and phosphor materials result in a large full width at half maximum (FWHM) spectrum, and consequently, a reduced color gamut.

[0005] Therefore, separate sources of light with different wavelengths, such as red, green, and blue light, are needed to have an expanded color gamut suitable for microLEDs. [Overview of the project] [Means for solving the problem]

[0006] To alleviate at least some of the above-mentioned problems, a color conversion resonator system and a method for forming a color conversion resonator system are provided according to the attached claims.

[0007] A color conversion resonator system comprising: a first partial reflection region configured to transmit light of a first principal peak wavelength and reflect light of a second principal peak wavelength; a second partial reflection region configured to transmit light of the first and second principal peak wavelengths at least partially and reflect light of a third principal peak wavelength; a third partial reflection region configured to reflect light having a third principal peak wavelength at least partially; and a system that receives input light having a first principal peak wavelength through the first partial reflection region and converts at least a portion of the light of the first principal peak wavelength. A first color-converting resonator cavity configured to provide light of two principal peak wavelengths, wherein the first color-converting resonator cavity is configured such that a second principal peak wavelength resonates within the first color-converting resonator cavity and resonant light having the second principal peak wavelength is output through a second partial reflection region; and a second color-converting resonator cavity configured to receive input light including the second principal peak wavelength through the second partial reflection region, convert at least a portion of the second principal peak wavelength, and provide light of a third principal peak wavelength, wherein the second color-converting resonator cavity is configured such that the third principal peak wavelength is A color conversion resonator system is provided, comprising: a second color conversion resonator cavity, which resonates within the second color conversion resonator cavity and is configured to output resonant light having a third principal peak wavelength through a third partial reflection region, wherein the first color conversion resonator cavity and the second resonator cavity are configured to partially overlap, provide non-overlapping portions and overlapping portions, thereby defining a first light-emitting surface and a second light-emitting surface, respectively, the first light-emitting surface being configured to provide resonant light of a second principal peak wavelength, and the second light-emitting surface being configured to provide resonant light of a third principal peak wavelength.

[0008] Preferably, the third partial reflection region is further configured to reflect light having a fourth principal peak wavelength, and the color conversion resonator system comprises a fourth partial reflection region configured to at least partially reflect light having a fourth principal peak wavelength, and a third color conversion resonator cavity configured to receive input light including the third principal peak wavelength through the third partial reflection region, convert at least a portion of the third principal peak wavelength, and provide light of the fourth principal peak wavelength, wherein the third color conversion resonator cavity is configured such that the fourth principal peak wavelength is the third color conversion resonator The invention further comprises a third color-converting resonator cavity, which resonates within the cavity and is configured to output resonant light having a fourth principal peak wavelength through a fourth partial reflection region, wherein the second and third color-converting resonator cavities are configured to partially overlap, non-overlapping, and overlapping portions, thereby defining a second and third light-emitting surface, respectively, the second light-emitting surface being configured to provide resonant light of a third principal peak wavelength, and the third light-emitting surface being configured to provide resonant light of a fourth principal peak wavelength.

[0009] Such a configuration forms a monolithic system of epitaxial layers. In contrast to known monolithic LED devices, the color conversion resonator system of the present invention can provide distinct light of different wavelengths in a vertically integrated system. Growing such a color conversion resonator system monolithically eliminates the need for the conventional time-consuming "pick and place" method, in which LEDs are grown individually on a wafer and moved separately onto the display electronics. Furthermore, the partial overlap created between the first and second color conversion resonator cavities and the second and third color conversion resonator cavities due to selective etching allows the system to emit light of different colors with relatively narrow full width at half maximum (FWHM) spectra. Moreover, such a system improves the directivity of the emitted light and reduces the need for the integration of collimators or lenses, which may require complex processes for implementation. Advantageously, this results in improved light output, enabling narrow beam angles and narrow spectra for use, for example, in near-eye displays. Advantageously, the color conversion resonator system enables the formation of wide color gamut displays and high-resolution micro-LED arrays. Advantageously, the optical color conversion resonator system enables wafer-level processing, narrow beam angle emission without the use of a collimator, and compressed emission spectra with reduced efficiency losses.

[0010] A color conversion resonator system can be configured to emit red, green, and blue light from different light-emitting surfaces. Such a system is particularly useful for micro-LED applications for display screens.

[0011] Preferably, the first partial reflection region and the second partial reflection region are λ in (N+1). converted / 2n(λ converted The distances are separated by the product of ), where N is a positive integer and λ converted This is the second main peak wavelength, and n( λ converted) is the effective refractive index of the material separating the first partial reflection region and the second partial reflection region, thereby defining the length of the first color conversion resonator cavity, and / or the second partial reflection region and the third partial reflection region are separated by a distance of (N + 1) multiplied by λ converted / 2n(λ converted ), where N is a positive integer and λ converted is the third main peak wavelength, and n(λ converted ) is the effective refractive index of the material separating the second partial reflection region and the third partial reflection region, thereby defining the length of the second color conversion resonator cavity, and / or the third partial reflection region and the fourth partial reflection region are separated by a distance of (N + 1) multiplied by λ converted / 2n(λ converted ), where N is a positive integer and λ converted is the fourth main peak wavelength, and n(λ converted ) is the effective refractive index of the material separating the third partial reflection region and the fourth partial reflection region, thereby defining the length of the third color conversion resonator cavity.

[0012] Such a configuration enables constructive interference of the second main peak wavelength in the first color conversion resonator cavity, constructive interference of the third main peak wavelength in the second color conversion resonator cavity, and constructive interference of the fourth main peak wavelength in the third color conversion resonator cavity. Advantageously, careful adjustment of the color conversion resonator cavity enables improvement of the output emission.

[0013] Preferably, the color conversion resonator system further comprises at least one LED. More preferably, the color conversion resonator system comprises a first LED configured to control light emission from the first light emitting surface and a second LED configured to control light emission from the second light emitting surface.

[0014] More preferably, the color conversion resonator system includes a first LED configured to control light emission from a first light emitting surface, a second LED configured to control light emission from a second light emitting surface, and a third LED configured to control light emission from a third light emitting surface. Advantageously, such a system allows each pixel to be individually controlled.

[0015] For example, a system having at least three individual LEDs configured to emit red, green, and blue light can allow only blue pixels to emit light, or only green pixels to emit light, or only red pixels to emit light. In addition, combinations of pixels can emit light such that blue and green light are emitted in combination, or blue and red light are emitted in combination, or red and green light are emitted in combination, or red, green, and blue light are emitted in combination.

[0016] Preferably, the input light is at least one of ultraviolet (UV) light and blue light, and preferably, the input light has a wavelength of 340 nm to 460 nm. Advantageously, a high-quality established input LED source having a wavelength shorter than the wavelengths of the additional visible light colors required for an optical display is used to provide an input pump source for color conversion within the color conversion resonator cavity.

[0017] Preferably, at least one of the color conversion resonator cavities includes at least one quantum well layer, and preferably, at least one quantum well layer is arranged to coincide with the antinode of the standing wave wavelength of the color conversion resonator cavity for the converted light, thereby improving at least one of the intensity, spectral width, and directivity of the output light having the resonant conversion wavelength of the light.

[0018] Alternatively, or in addition, a color conversion resonator system, wherein at least one of the color conversion resonator cavities includes a quantum well layer including at least one quantum well and a further quantum well layer including at least one quantum well, and the separation of the quantum well layer and the further quantum well layer is N multiplied by λ converted / 2n(λ converted ), where , N is a positive integer, λ converted is the wavelength of the resonant light in the color conversion resonator cavity, and n(λ converted ) is the effective refractive index of the material between the quantum well layer and the further quantum well layer at the wavelength of the resonant light in the color conversion resonator cavity, a color conversion resonator system is provided.

[0019] Advantageously, such a configuration places each quantum well layer at the antinode of the resonant standing wave of the light in the color conversion resonator cavity, thereby enabling constructive interference and enhancement of the output light.

[0020] Preferably, at least one of the color conversion resonator cavities includes at least one absorption layer configured to absorb the input light, thereby enabling transfer of energy from the input light wavelength into at least one of the quantum well layers, and preferably the absorption layer includes a material having an energy bandgap lower than the energy of the input light. Advantageously, the absorption layer enables carriers to recombine within the quantum well layer, thus assisting the process that enables improvement of the resonance of the converted light emitted by the quantum well layer.

[0021] Preferably, the color conversion resonator system further includes at least one diffusion barrier configured to reduce diffusion of carriers from at least one of the color conversion resonator cavities. Advantageously, the use of the diffusion barrier reduces carrier diffusion, and thus improves radiative recombination within the color conversion resonator cavity.

[0022] Preferably, the color conversion resonator system comprises at least one additional partial reflection region corresponding to at least one of the first, second, or third light-emitting surfaces. Advantageously, the partial reflection region is tuned to optimize which wavelengths are emitted by the light-emitting pixels formed by the composite of the color conversion resonator cavity system and the LED device. Advantageously, light of a predetermined wavelength is reused within the color conversion resonator cavity to improve the conversion efficiency from input light with a dominant peak wavelength to output light with a different dominant peak wavelength.

[0023] Preferably, at least one of the partial reflection region and / or further partial reflection region includes a distributed Bragg reflector (DBR), and preferably the DBR is at least one of a dual-band DBR, a conventional DBR, and a vertical stack of two DBRs.

[0024] Preferably, at least one of the partial reflection regions includes a blue wavelength-centered low Herpin refractive index Bragg reflector (DBR), or a green wavelength-centered low Herpin refractive index DBR, or a red wavelength-centered low Herpin refractive index DBR.

[0025] Preferably, the color conversion resonator system comprises a blue wavelength-centered low Harpin refractive index DBR, a green wavelength-centered low Harpin refractive index DBR, and a red wavelength-centered low Harpin refractive index DBR. Advantageously, such a configuration produces one pixel optimized for blue wavelength light, one pixel optimized for green wavelength light, and one optimized pixel for red wavelength light.

[0026] Preferably, at least one of the partial reflection region and the color conversion resonator cavity includes an epitaxial crystalline layer, and preferably, the color conversion resonator system includes at least one of a dielectric material and a III-V semiconductor material. Advantageously, the partial reflection region is formed using a technique that allows for the seamless integration of the functional layers within the color conversion resonator cavity.

[0027] Preferably, the color conversion resonator system forms an array of pixels, the array comprising a first pixel configured to emit light of a different wavelength than a second pixel, and a third pixel configured to emit light of a different wavelength than the first and second pixels. Preferably, The first and / or second pixels, and / or third pixels, include further partial reflection regions corresponding to their light-emitting surfaces. Advantageously, light-emitting pixels based on a composite of a light-emitting device, such as an LED device, and a color conversion resonator cavity, mean that high-purity color light-emitting pixels can be formed on a scale that means they can be implemented within a high-resolution microscale array.

[0028] The color conversion resonator system is preferably produced by forming at least one of the color conversion resonator cavities on a substrate, preferably by forming at least one of the color conversion resonator cavities on a substrate, which involves the epitaxial growth of multiple layers. The method includes forming at least one of the partial reflection regions on a substrate, preferably by forming at least one of the partial reflection regions on a substrate, which involves sequentially forming the color conversion resonator cavity and at least one of the partial reflection regions on a substrate. The method preferably includes bonding the color conversion resonator system to at least one LED and selectively etching the color conversion resonator system to provide an emitting surface. Advantageously, forming the color conversion resonator cavities on a substrate allows for the formation of large-scale color conversion resonator cavities for integration with light-emitting devices. Advantageously, known growth and processing techniques can be applied to form the structure using high-quality, low-defect-density materials that provide efficient light input and light conversion for use in light-emitting pixels.

[0029] Further aspects of the present invention will become apparent from the description and the appended claims.

[0030] A detailed description of embodiments of the present invention will be given only by reference to the figures. [Brief explanation of the drawing]

[0031] [Figure 1] Figure 1 shows a cross-sectional view of the system of three color conversion resonator cavities. [Figure 2] Figure 2 shows a cross-sectional view of the system in Figure 1, in which the color conversion resonator cavity is joined to the LED. [Figure 3] Figure 3 shows a cross-sectional view of the system of three color conversion resonator cavities from Figure 2, which has been further modified. [Figure 4] Figure 4 shows a cross-sectional view of the system of three color conversion resonator cavities from Figure 3, which has been further modified. [Figure 5] Figure 5 shows a cross-sectional view of the system of three color conversion resonator cavities from Figure 4, which has been further modified. [Figure 6] Figure 6 shows a cross-sectional view of the optical input and the emission from the system of three color conversion resonator cavities. [Figure 7] Figure 7 shows a cross-sectional view of a system of three color conversion resonator cavities with independently addressable optical inputs. [Figure 8] Figure 8 shows a cross-sectional view of the system of three color conversion resonator cavities. [Figure 9] Figure 9 shows a cross-sectional view of the system of three color conversion resonator cavities from Figure 8, which has been further modified. [Figure 10] Figure 10 shows a cross-sectional view of the system of three color conversion resonator cavities from Figure 9, which has been further modified. [Figure 11] Figure 11 shows a cross-sectional view of the three color conversion resonator cavity system from Figure 10, which has been further modified. [Modes for carrying out the invention]

[0032] To address the disadvantages associated with the devices in the prior art, at least as described above, structures and methods for forming such structures are described below with reference to Figures 1 to 11. A color conversion resonator cavity system is described that provides a sophisticated way to efficiently downconvert and reuse input light in order to provide a multicolor wavelength light output system. Advantageously, such a system provides high-purity narrow FWHM output light with a narrower beam angle, This improves light output control and provides a system with a superior color gamut and controlled directivity. Advantageously, the formation and processing of epitaxially grown crystal layers can be used to provide a high-quality, and therefore highly efficient, system for improved light output. Such epitaxially grown crystal layers can be used to form a color conversion resonator cavity system in a single growth process, or groups of one or more epitaxially grown crystal layers can be individually optimized and joined together to form a color conversion resonator cavity, thereby enabling the parallel growth and processing of individually optimized layers.

[0033] Furthermore, advantageously, the formation and fabrication of color conversion resonator cavities formed from epitaxially grown systems allows for the definition of light-emitting surfaces associated with the emission of different colors of light, thereby advantageously enabling micro-LED pixel arrays (100 μm 2 The following, and preferably 16 μm 2 It is associated with pixels that can be formed on a scale suitable for implementation in high-resolution microLED arrays having the following pixel light-emitting surfaces and a pixel pitch of 10 μm or less, and preferably 5 μm or less.

[0034] Figure 1 shows a cross-sectional view of a color conversion resonator system 100, which is an epitaxial structure having three color conversion resonator cavities. The epitaxial structure is formed and later fabricated to provide a color conversion resonator system combined with an optical input device, as described with reference to Figures 2 to 11.

[0035] The color conversion resonator system 100 is a laminate of epitaxial crystalline compound semiconductor layers. The epitaxial crystalline compound semiconductor layers are provided by sequential growth of epitaxial layers on a growth substrate 102. The growth substrate 102, for example, silicon, silicon carbide, sapphire, gallium nitride, or other suitable growth substrate, can be removed after the epitaxial compound semiconductor crystalline layers have been formed. Advantageously, the growth of such epitaxial compound semiconductor crystalline layers can be controlled with high precision to result in a high-quality material with a low defect density, as well as a controlled layer thickness and efficient radiative recombination of carriers at controlled wavelengths of light.

[0036] The three chromatic conversion resonator cavities of the epitaxial structure are each designed to receive input light from one or more input light sources, convert the input light having a primary peak wavelength from the input light sources, and provide output light having different, converted primary peak wavelengths of light. When the epitaxial structure is fabricated and combined with the input light source, the converted primary peak wavelength light resonates within its respective chromatic conversion resonator cavities of the epitaxial structure, and is designed so that multiple resonant converted lights of different wavelengths are output from the chromatic conversion resonator system 100. Appropriate fabrication of the epitaxial structure enables the provision of a polychromatic emitter in which multiple chromatic conversion resonator cavities are associated with different light-emitting surfaces for emitting light of different wavelengths, as described at least herein.

[0037] Figure 1 shows a buffer 104 grown on a growth substrate 102. The substrate 102 is a silicon substrate, and the buffer 104 is an aluminum gallium nitride (AlGaN) epitaxial layer. In further examples, alternatively or in addition, the buffer 104 is formed of at least one of aluminum gallium nitride (AlGaN), aluminum nitride (AlN), and gallium nitride (GaN). An etch stop 106 is grown on the buffer 104. The etch stop 106 is an AlGaN layer with a relatively high aluminum content. The etch stop 106 facilitates precise control of the processing steps used to remove material from the epitaxial structure 100 in order to provide a processed system.

[0038] A partial reflection region 108 is grown on the etch stop 106. A chromatic conversion resonator cavity 110 and a further partial reflection region 112 are grown on the partial reflection region 108. The chromatic conversion resonator cavity 110 is configured to receive input light of a main peak wavelength and convert this input light into converted light of a different main peak wavelength.

[0039] Further color-conversion resonator cavities 114 and further color-conversion resonator cavities 116 are grown on the partially reflective region 112. The color-conversion resonator cavities 114 are configured to receive input light of a different principal peak wavelength and convert this input light into converted light of a different principal peak wavelength. In further examples, an etch-stop layer is formed between the partially reflective region 112 and the further color-conversion resonator cavities 114. The etch-stop layer (not shown) facilitates precise control in subsequent steps for removing material from the structure. In further examples, alternative or additional etch-stop layers are formed within the structure to facilitate control of layer removal by the etching process.

[0040] Further color-converting resonator cavities 118 and further partial-reflection regions 120 are grown on the partially reflective region 116. The color-converting resonator cavities 118 are configured to receive input light of a further principal peak wavelength and convert this input light into converted light of a different principal peak wavelength. In further examples, an etch-stop layer is formed between the partially reflective region 116 and the further color-converting resonator cavities 118. The etch-stop layer (not shown) facilitates precise control in subsequent steps for removing material from the structure. In further examples, alternative or additional etch-stop layers are formed within the structure to facilitate control of layer removal by the etching process.

[0041] The chromatic resonator system 100 forms a monolithic system of epitaxial layers. Such epitaxial layers are planar layers. The chromatic resonator system 100 in Figure 1 is formed using epitaxial compound semiconductor growth techniques such as metal-organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE). In addition, or alternatively, the chromatic resonator system 100 may be formed using any suitable technique.

[0042] The order of the epitaxial layers is such that, when the system is inverted and joined to the LED, the order of proximity of the color conversion resonator cavities to the LED is such that shorter wavelength light, such as UV light from the LED, is absorbed in the color conversion resonator cavity 118, and then longer wavelength light, such as blue light, is output from the color conversion resonator cavity 118. The light output from the color conversion resonator cavity 118 and the LED is absorbed in the color conversion resonator cavity 114. The color conversion resonator cavity 114 then outputs light with a longer wavelength than that of the LED and the color conversion cavity 118, such as green light. The light output from the color conversion resonator cavity 118, the color conversion resonator cavity 114, and the LED is absorbed in the color conversion resonator cavity 110, which then outputs even longer wavelength light, such as red light. This means that the input light can be absorbed and emitted by the chromatic conversion resonator cavities in such a way that the light emitted by the successive chromatic conversion resonator cavities is reused before it leaves the final structure.

[0043] Advantageously, growing the epitaxial structure of the color conversion resonator system 100 in this order means that the color conversion resonator cavities 118, 114, and 110 can be manipulated using the growth substrate 102 on which the color conversion resonator system 100 layer is formed, thereby facilitating bonding with LED structures without requiring further processing steps to enable alignment and bonding of the color conversion resonator system 100 with one or more light-emitting devices formed on different substrates.

[0044] The color conversion resonator system 100 described with respect to Figure 1 is formed from a nitride-based material. Specifically, the epitaxial crystalline compound semiconductor layer is a gallium nitride (GaN)-based material. Although the structure described with respect to Figure 1 relates to a nitride-based semiconductor compound material, those skilled in the art will understand that the concepts described herein are also applicable to other materials, in particular to other semiconductor materials, such as other III-V compound semiconductor materials or II-VI compound semiconductor materials.

[0045] The provision of three color-converting resonator cavities makes it possible to form a structure that emits multiple different principal peak wavelengths of light. Those skilled in the art will understand that in further examples, alternative or additional structures may be used to provide different structures that emit different principal peak wavelengths of light.

[0046] The partial reflection region 108 and the further partial reflection region 112 are λ in (N+1). converted / 2n(λ converted The distances are separated by the product of ), where N is a positive integer and λ converted n(λ) is the converted main peak wavelength emitted from the color conversion resonator cavity 110. converted ) is the effective refractive index of the material separating the partial reflection region 108 and the further partial reflection region 112. Such a configuration allows the light of the converted main peak wavelength to resonate within the color conversion resonator cavity 110. In further examples, the partial reflection region 108 and the further partial reflection region 112 are separated by different distances.

[0047] Similarly, the partial reflection region 112 and the further partial reflection region 116 are λ in (N+1). converted / 2n(λ converted The distances are separated by the product of ), where N is a positive integer and λ converted n(λ) is the converted main peak wavelength emitted from the color conversion resonator cavity 114. converted ) is the effective refractive index of the material separating the partial reflection region 112 and the further partial reflection region 116. Such a configuration allows the light of the converted main peak wavelength to resonate within the color conversion resonator cavity 114. In further examples, the partial reflection region 112 and the further partial reflection region 116 are separated by different distances.

[0048] In addition, the partial reflection region 116 and the further partial reflection region 120 are λ in (N+1) converted / 2n(λ converted The distances are separated by the product of ), where N is a positive integer and λ convertedn(λ) is the converted main peak wavelength emitted from the color conversion resonator cavity 118. converted ) is the effective refractive index of the material separating the partial reflection region 116 and the further partial reflection region 120. Such a configuration allows the light of the converted main peak wavelength to resonate within the color conversion resonator cavity 118. In a further example, the partial reflection region 116 and the further partial reflection region 120 are separated by different distances.

[0049] The chromatic conversion cavity 110 includes at least one quantum well layer. The quantum well layer includes multiple quantum wells. In further examples, the quantum well layer includes a single quantum well. The quantum well layer is located at the wave antinode of the standing wavelength of the chromatic conversion cavity for the converted principal peak wavelength emitted from the chromatic conversion cavity 110. Similarly, the chromatic conversion cavity 114 includes at least one quantum well layer located at the wave antinode of the standing wavelength of the chromatic conversion cavity for the converted principal peak wavelength emitted from the chromatic conversion cavity 114. The quantum well layer includes multiple quantum wells. In further examples, the quantum well layer includes a single quantum well. In addition, the chromatic conversion cavity 118 includes at least one quantum well layer located at the wave antinode of the standing wavelength of the chromatic conversion cavity for the converted principal peak wavelength emitted from the chromatic conversion cavity 118. The quantum well layer includes multiple quantum wells. In further examples, the quantum well layer includes a single quantum well. Such a configuration improves at least one of the output light having intensity, spectral width, and resonant converted principal peak wavelength. In a further example, color conversion resonator cavities 110, 114, Each of the 118 layers has alternative or additional layers, for example, single or multiple quantum wells within the quantum well layer are positioned to coincide with wave antinodes of different light conversion wavelengths within their respective color conversion resonator cavities 110, 114, and 118.

[0050] The chromatic conversion resonator cavities 110, 114, and 118 each contain multiple quantum wells (MQWs). In further examples, the chromatic conversion resonator cavities 110, 114, and 118 each contain single quantum wells (SQWs). In further examples, the chromatic conversion resonator cavities 110, 114, and 118 contain different layers from each other. The quantum well layers are designed to allow carriers to recombine, thereby enabling radiative recombination to produce an output of light with a dominant peak wavelength different from the wavelength of the input light that gives rise to the emission of output light.

[0051] To enable emission, the input light is absorbed by an absorption layer associated with each quantum well layer inside each of the color conversion resonator cavities 110, 114, and 118. The input light absorbed in the absorption layer has a main peak wavelength. In one example, the input light is blue light with a wavelength of approximately 450 nm. The wavelength of the light output by the quantum well layer is longer than the wavelength input. The output wavelength of the light is the conversion wavelength of the light. The input light is blue light, but in further examples, additional or alternative wavelengths of the input light are used. More preferably, each absorption layer contains a material having an energy bandgap lower than the energy of the input main peak wavelength.

[0052] The epitaxial structure of the color conversion resonator system 100 is designed to be inverted and bonded to the light-emitting device once formed, with the substrate 102, buffer material 104, and etch stop 106 being removed. Thus, the sequence of input light and subsequent converted output light layers within the epitaxial structure of the color conversion resonator system 100 is considered before growth, and the formation of the partial reflection regions is described in more detail below with reference to Figures 2 and 3. The partial reflection regions 108, 112, 116, and 120 are distributed Bragg reflectors (DBRs). In further examples, the partial reflection regions 108, 112, 116, and 120 include alternative or additional structures.

[0053] Once system 100 is formed, it is inverted and bonded to the LED structure. This is shown in Figure 2. Figure 2 shows a color conversion resonator system 200 comprising a light-emitting diode (LED) 224 and a substrate device 202. The substrate device is a temporary substrate used to facilitate the fabrication of the color conversion resonator system 200. Alternatively, in one example, the substrate device 202 is a complementary metal oxide semiconductor (CMOS) backplane composited with a light-emitting device, such as a light-emitting diode device, to provide and control the input light in the final structure. The color conversion resonator system 100 described with reference to Figure 1 is composited with the substrate device 202 and LED 224 by inverting the color conversion resonator structure 100 described with reference to Figure 1 and bonding the epitaxial layer of the uppermost partial reflection region 120 to the LED 224 using a bonding layer 222. Subsequently, the substrate 102, buffer material 104, and etch stop 106 are removed, leaving the structure shown in Figure 2.

[0054] Advantageously, the order of proximity of the color-converting resonator cavities to the LED224 is such that shorter wavelength light, such as blue light, from the LED224 is absorbed in the first color-converting resonator cavity; then, the light emitted from the first color-converting resonator cavity and the LED224 is absorbed in the second color-converting resonator cavity; and finally, the light emitted from the first color-converting resonator cavity, the second color-converting resonator cavity, and the LED224 is absorbed in the third color-converting resonator cavity. This means that the input light can be absorbed and emitted by the color-converting resonator cavities in such a way that the light emitted by the color-converting resonator cavities is reused before it leaves the final structure.

[0055] Therefore, the partial reflection region 120 is shown just above the junction layer 222 on the LED 224. Above the partial reflection region 120 is a color conversion resonator cavity 118, followed by a further partial reflection region 116. Above the partial reflection region 116 is a further color conversion resonator cavity 114, followed by a further partial reflection region 112. Above the partial reflection region 112 is a further color conversion resonator cavity 110, followed by a further partial reflection region 108.

[0056] The color conversion resonator system 100 in Figure 1 is fabricated for bonding to the LED 224, as shown in Figure 2. In a further example, the epitaxial layer of the color conversion resonator system 200 is grown directly on the LED 224. Advantageously, such direct growth of the layer on the LED 224 eliminates the need for a later bonding step in the manufacturing of such a device.

[0057] While the epitaxial layers of the color conversion resonator system 100, as described with reference to Figure 1, are shown to be grown in a specific order to enable structural bonding to the light-emitting diode structure, in further examples, the growth order is reversed to preserve efficient absorption and emission of light from shorter wavelengths to longer wavelengths, from the color conversion resonator cavity closest to the input LED light source to the color conversion resonator cavity furthest from the input LED.

[0058] Figure 2 shows the color conversion resonator system 200. As described above, the color conversion resonator system 200 is formed by inverting the color conversion resonator system 100, bonding the color conversion resonator system 100 to the LED 224 via the bonding layer 222, thereby bonding the partial reflection region 120 directly to the LED 224 and the bonding layer 222, and the partial reflection region 108 to the color conversion resonator system 200, and then removing the substrate 102 and buffer material 104 from the color conversion resonator system 200. The color conversion resonator system 100 can be inverted by manipulating the substrate 102 and buffer material 104 of the color conversion resonator system 100 before removing the above layers.

[0059] The LED 224 is bonded to the partial reflection region 120 using a dielectric junction. The surface of the LED 224 that will be bonded to the partial reflection region 120 is terminated with a high-density oxide film to facilitate such bonding. The surface of the partial reflection region 120 that will be bonded to the input LED 224 is also terminated with a high-density oxide film to facilitate wafer-level oxide bonding. Therefore, the main light-emitting surface of the LED 224 is positioned in close proximity to, or in contact with, the partial reflection region 120 so that the light output from the LED 224 serves as the input light for the color conversion resonator system 200.

[0060] In further examples, the LED 224 is bonded to the partially reflective region 120 using polymer bonding, such as polyimide bonding. In further examples, additional or alternative bonding mechanisms are used to attach the LED 224 to the partially reflective region 120. Advantageously, the LED 224 is bonded to the partially reflective region 120 to minimize interface losses of light emitted from the LED 224 at the interface with the color conversion resonator system 200, thereby forming a single device.

[0061] The chromatic resonator system 200 is configured to receive input light of a first principal peak wavelength and convert this input light into light of a second principal peak wavelength. The chromatic resonator system 200 further converts the light of the second principal peak wavelength (and the light of the first principal peak wavelength) into light of a third principal peak wavelength. The light of the third principal peak wavelength (and the first and second principal peak wavelengths) is then converted into light of a fourth principal peak wavelength.

[0062] This mechanism allows the color conversion resonator cavity 118 to receive input light of the first principal peak wavelength from the LED 224 in front of the further color conversion resonator cavities 114 and 110. This is because the color conversion resonator cavity 118 is configured for resonant light of the second principal peak wavelength. Furthermore, this is efficient when this wavelength is smaller than the third and fourth main peak wavelengths. The third main peak wavelength is greater than the second main peak wavelength and smaller than the fourth main peak wavelength.

[0063] For example, the color conversion resonator cavity 118 can be optimized for the wavelength of light corresponding to blue light (e.g., approximately 450 nm, so that the input light, e.g., UV light at approximately 380 nm, has a shorter wavelength), a further color conversion resonator cavity 114 can be optimized for the wavelength of light corresponding to green light (e.g., approximately 530 nm, so that the input light, e.g., blue light and UV light, has a shorter wavelength), and a further color conversion resonator cavity 110 can be optimized for the wavelength of light corresponding to red light (e.g., approximately 630 nm, so that the input light, e.g., green light, blue light, and UV light, has a shorter wavelength).

[0064] To enable resonance of light wavelengths, the partial reflection regions 108, 112, 116, and 120 are configured to improve the passage of light from the light input LED 224 through the color conversion resonator system 200 to the light-emitting surface.

[0065] The partial reflection region 120 has a relatively high reflectivity for the wavelength of the converted light generated within the color conversion cavity 110 and a relatively high transmittance for the wavelength of the input light. In one example, the partial reflection region 120 has a relatively low reflectivity, for example, less than 20% of the main peak wavelength of the input light from the LED 224 joined to the partial reflection region 120, and a relatively high reflectivity, for example, more than 80% of the converted light generated by the absorption and re-emission of the input light within the color conversion cavity 118. In further examples, different reflectivity values ​​are used for the partial reflection region 120. In one example, the partial reflection region 120 has a reflectivity of less than 10% of the input light and a reflectivity of more than 90% of the converted light. In further examples, the partial reflection region 120 has a reflectivity of less than 5% of the input light and a reflectivity of more than 95% of the converted light. Similarly, the partial reflection region 116 has a relatively high reflectivity for the wavelength of the converted light generated within the color conversion cavity 114 and a relatively high transmittance for the wavelength of the input light.

[0066] In one example, the partial reflection region 116 has a relatively low reflectivity, for example, less than 20% of the main peak wavelength of the input light, and a relatively high reflectivity, for example, more than 80% of the converted light generated by the absorption and re-emission of the input light within the color conversion resonator cavity 114. In further examples, different reflectivity values ​​are used for the partial reflection region 116. In one example, the partial reflection region 116 has a reflectivity of less than 10% of the input light and a reflectivity of more than 90% of the converted light. In further examples, the partial reflection region 116 has a reflectivity of less than 5% of the input light and a reflectivity of more than 95% of the converted light. In addition, the partial reflection region 112 has a relatively high reflectivity with respect to the wavelength of the converted light generated within the color conversion resonator cavity 110, and a relatively high transmittance with respect to the wavelength of the input light.

[0067] In one example, the partial reflection region 112 has a relatively low reflectivity, for example, less than 20% of the main peak wavelength of the input light, and a relatively high reflectivity, for example, more than 80% of the converted light generated by the absorption and re-emission of the input light within the color conversion resonator cavity 110. In further examples, different reflectivity values ​​are used for the partial reflection region 112. In one example, the partial reflection region 112 has a reflectivity of less than 10% of the input light and a reflectivity of more than 90% of the converted light. In further examples, the partial reflection region 112 has a reflectivity of less than 5% of the input light and a reflectivity of more than 95% of the converted light.

[0068] In one example, the partial reflection region 108 has a relatively low reflectivity, for example, less than 20% of the main peak wavelength of the input light, and a relatively high reflectivity, for example, more than 80% of the converted light generated by the absorption and re-emission of the input light within the color conversion resonator cavity 110. In further examples, Different reflectance values ​​are used for the partial reflection region 108. In one example, the partial reflection region 108 has a reflectance of less than 10% of the input light and a reflectance of more than 90% of the converted light. In a further example, the partial reflection region 108 has a reflectance of less than 5% of the input light and a reflectance of more than 95% of the converted light.

[0069] The partial reflection regions 108, 112, 116, and 120 are formed from alternating epitaxial crystalline layers with different refractive indices. The refractive indices and thicknesses of the layers are selected to produce a reflectivity response as a function of the wavelength of incident light in the partial reflection regions 108, 112, 116, and 120. This method of DBR growth enables the seamless formation of a high-crystal-quality color conversion resonator system 100.

[0070] Partial reflection regions 108, 112, 116, and 120 are DBRs, but in further examples alternative or additional regions are used. In further examples, partial reflection region 108 includes a DBR, or a vertical stack of two different DBRs, or a biband DBR. In further examples, partial reflection region 108 is omitted. In further examples, partial reflection regions 112 and / or partial reflection regions 116 and / or partial reflection regions 120 include DBRs having relatively high reflectance at the conversion wavelength of light and low reflectance at the input wavelength. For example, as a filter for high reflectance of blue light and low reflectance of green and red light, or as a filter for low reflectance of blue light and high reflectance of green and red light. Both the reflectance and wavelength ranges of light can also be implemented. When "H" defines a high refractive index material with a thickness of one-quarter wavelength and "L" defines a low refractive index material with a thickness of one-quarter wavelength, for N layers,

number

number

number

number

[0071] The partial reflection regions 108, 112, 116, and 120 are DBRs formed from nitride-based epitaxial layers, but in further examples, the partial reflection regions 108, 112, 116, and 120 are formed by different methods, in addition to, or alternatively, while maintaining functionality that allows for the reflection of some wavelengths of light and the transmission of different wavelengths of light. For example, partial reflection Region 108, and / or partially reflective region 112, and / or partially reflective region 116, and / or partially reflective region 120 are formed from a dielectric laminate. In a further example, partially reflective region 108, and / or partially reflective region 112, and / or partially reflective region 116, and / or partially reflective region 120 are formed from alternating layers of GaN and porous GaN. Since the porosity of the epitaxial crystalline layers is related to their refractive index, the porosity of the epitaxial crystalline GaN layers forming partially reflective regions 108, 112, 116, and 120 is controlled to yield a desired reflectivity response as a function of wavelength. Advantageously, a DBR thus formed can be provided using GaN alone.

[0072] Preferably, at least one diffusion barrier is provided that is configured to reduce the diffusion of carriers from the color conversion resonator cavities 110, 114, and 118. The diffusion barrier is incorporated into the structure to improve the resonant emission of the converted light within the color conversion resonator cavities.

[0073] Figure 3 shows a color conversion resonator system 300 comprising an LED 224, a junction layer 222, a partial reflection region 120, a color conversion resonator cavity 118, a further partial reflection region 116, and a further color conversion resonator cavity 114. Each of these layers is grown sequentially as described above (for example, in the inverted order shown in Figure 1, or in the uninverted order shown in Figure 2). On this series of layers, layers partially etched from the structure described with respect to Figures 1 and 2 are shown. The etched layers are the partial reflection region 112, the color conversion resonator cavity 110, and the partial reflection region 108. These layers were etched such that layers 108, 110, and 112 form a partial overlap region with the remaining layers 224, 222, 120, 118, 116, and 114.

[0074] The color conversion resonator system 300 is formed by selectively etching the color conversion resonator system 200 within a first region. The surface of the partial reflection region 108 is selectively patterned according to a well-known technique. Such selective patterning allows for selective etching of regions of the color conversion resonator system (e.g., using well-known wet or dry etching techniques). As shown in Figure 3, the first etch removed the partial reflection regions 108, 112 and the color conversion resonator cavity 110 from the color conversion resonator system 200 within the first region. The use of an etch stop (not shown) between the color conversion resonator cavity 114 and the partial reflection region 112 facilitates control of material removal by etching. In further examples, in addition or alternatively, the partial reflection region 112 is not removed during the first etch process. The first etch process forms an emissive surface region associated with the partial reflection region 108. Although one region is shown as the partial reflection region 108, in further examples, multiple regions are etched to provide an emissive surface associated with the partial reflection region 108. These multiple regions are used to form an array.

[0075] Once a first etching process is performed to selectively remove the material associated with the color conversion resonator cavity 110, a second etching process is performed. This is shown in Figure 4.

[0076] Figure 4 shows a color conversion resonator system 400 comprising an LED 224, a bonding layer 222, a partial reflection region 120, and a color conversion resonator cavity 118. These layers, grown sequentially as described above, remain unetched. On layers 224, 222, 120, and 118 are a partial reflection region 116 and a further color conversion resonator cavity 114. The partial reflection region 116 and the color conversion resonator cavity 114 were selectively etched such that layers 114 and 116 form a partial overlap region with the remaining layers 224, 222, 120, and 118. As described above, on layers 114 and 116 are a further partial reflection region 112, a further color conversion resonator cavity 110, and a further partial reflection region 108. As a result, layers 112, 110, and 108 form a partial overlap region with layers 114 and 116. The use of an etch stop (not shown) between the color conversion cavity 118 and the partial reflection region 116 facilitates control of material removal by etching. In further examples, in addition, or alternatively, the partial reflection region 116 is not removed during the second etch process. The second etch process forms an exposed light-emitting surface region associated with the color conversion cavity 114 and an exposed light-emitting surface region associated with the color conversion cavity 118. The etch process has been described with respect to cross-sectional views of three exposed regions associated with different layers of the color conversion cavity, but in further examples, multiple regions are etched to provide light-emitting surfaces associated with different layers of the color conversion cavity in order to form an array having a two-dimensional array of light-emitting pixels, where each light-emitting pixel has an associated light-emitting surface.

[0077] The color conversion resonator system 400 is formed by etching the color conversion resonator system 300 in a second region. The second etching removed the partial reflection region 116 and the color conversion resonator cavity 114 from the color conversion resonator system 300 in the second region.

[0078] Advantageously, such a system creates a color conversion resonator system 400 having light-emitting surfaces associated with different regions, the light-emitting surfaces provided by the exposed regions, and allowing light of three different main peak wavelengths to be emitted from the color conversion resonator system 400.

[0079] Figure 5 shows a chromatic conversion resonator system 400, described with reference to Figure 4, further modified to provide a first further partial reflection region 526, a second further partial reflection region 528, and a third further partial reflection region 530. The third further partial reflection region 530 associated with the chromatic conversion resonator cavity 110 is provided in place of the partial reflection region 108 formed within the initial epitaxial structure. Alternatively, the partial reflection region 108 remains in place, and the third further partial reflection region 530 is not formed within the structure shown in Figure 5. The first further partial reflection region 526 is formed on the exposed surface of the chromatic conversion resonator cavity 118. The second further partial reflection region 528 is formed on the exposed surface of the chromatic conversion resonator cavity 114.

[0080] Partial reflection regions 108, 112, 116, and 120, and / or further partial reflection regions 526, 528, and 530, include distributed Bragg reflectors (DBRs). Such DBRs are preferably one of a dual-band DBR, a conventional DBR, and a vertical stack of two DBRs. More preferably, partial reflection regions 112, 116, and 120 include a low Harpin refractive index DBR, while partial reflection region 108 and further partial reflection regions 526, 528, and 530 include a dual-band DBR, a conventional DBR, and a vertical stack of two DBRs.

[0081] In one example, partial reflection regions 108, 112, 116, and 120 include a blue wavelength-centered low Harpin refractive index DBR, or a green wavelength-centered low Harpin refractive index DBR, or a red wavelength-centered low Harpin refractive index DBR. For example, partial reflection region 120 may have a blue wavelength-centered low Harpin refractive index DBR so that the first pixel is optimized for blue wavelength light. Partial reflection region 116 may have a green wavelength-centered low Harpin refractive index DBR so that the second pixel is optimized for green wavelength light. Partial reflection region 112 may have a red wavelength-centered low Harpin refractive index DBR so that the third pixel is optimized for red wavelength light.

[0082] Such a configuration provided by the color conversion resonator system 500 allows the light-emitting surface to be provided to form an array of pixels. Etching and deposition of the aforementioned partial reflection regions results in the fabrication of a first pixel having a first further partial reflection region 526 as the uppermost layer, a second pixel having a second further partial reflection region 528 as the uppermost layer, and a third pixel having a third further partial reflection region 530 as the uppermost layer. The first pixel is The first pixel has a pixel dimension of 532. The second pixel has a pixel dimension of 534. The third pixel has a pixel dimension of 536. Pixel dimensions 532, 534, and 534 are shown in cross-section, but those skilled in the art will understand that in plan view, the pixels have exposed light-emitting surfaces associated with dimensions 532, 534, and 536 (for example, pixels having a square light-emitting surface area - in further examples, pixels with different forms of arrays and shapes of light-emitting surfaces are formed). Furthermore, the first and second partial reflection regions 526, 528 are shown to partially abut regions 116 and 112, respectively, but in further examples, the first and second partial reflection regions 526, 528 have different surface covering regions. Furthermore, the relative thickness of the cross-sectional image is shown in the figure, but those skilled in the art will understand that in further examples, the layers have different relative dimensions.

[0083] Figure 6 shows a chromatic conversion resonator system 500 bonded to a CMOS backplane 602, further indicating an input light 742 with a first main peak wavelength, a converted light 744 with a second main peak wavelength, a converted light 746 with a third main peak wavelength, and a converted light 748 with a fourth main peak wavelength.

[0084] The partial reflection region 120 is designed so that light 742 of the first main peak wavelength is transmitted and light 744 of the second main peak wavelength is reflected. The partial reflection region 116 is configured so that light 742 of the first main peak wavelength and light 744 of the second main peak wavelength are partially transmitted and light 746 of the third main peak wavelength is reflected. The partial reflection region 112 is configured so that light 742 of the first main peak wavelength, light 744 of the second main peak wavelength and light 746 of the third main peak wavelength are partially transmitted and light 748 of the fourth main peak wavelength is reflected.

[0085] The input light 742 with the first principal peak wavelength is emitted from the LED 224 through the color conversion resonator system 700. In the example in Figure 6, the first principal peak wavelength 742 corresponds to UV light. The light 742 with the first principal peak wavelength is transmitted through the partial reflection region 120 into the color conversion resonator cavity 118, where it is absorbed and downconverted by radiative recombination. The light 742 with the first principal peak wavelength is converted into light 744 with a second principal peak wavelength within the color conversion resonator cavity 118. In the example in Figure 6, the light with the second principal peak wavelength corresponds to blue light.

[0086] When an LED, such as the light-emitting device 224, is coupled to the color conversion resonator system 600, the angular distribution of light emission from the input LED 224 is changed. When input light from an LED 224 having such a Lambertian distribution of light emission is absorbed in the MQW and pump absorption layer of the color conversion resonator cavity 118, electron-hole pairs are generated in the MQW and pump absorption layer. The electrons and holes generated in the pump absorption layer move to the MQW. Therefore, the emitted light wavelength is determined by the MQW transition wavelength. When the QW material is AlxInyGa1-x-yN, this transition wavelength has a spectral range (FWHM: full width at half maximum) of approximately 30 nm for green and approximately 50 nm for red. Generally, AlxInyGa1-x-yN or AlxInyGa1-x-yP MQWs emit light in all directions, but the color conversion cavity resonator improves emission to satisfy the cavity conditions. As a result, the light 744 with the second main peak wavelength emitted from the color conversion resonator system 600 in Figure 6 exhibits a narrow beam angle and concentrated emission spectrum. Similar absorption and transmission occur in the other color conversion resonator cavities 114 and 110, according to their respective absorption and emission characteristics.

[0087] Light 744 of the second principal peak wavelength resonates within the color conversion resonator cavity 118 and is at least partially transmitted through the partial reflection region 116. Light 744 of the second principal peak wavelength is also transmitted through the first further partial reflection region 526 and emitted from the associated light-emitting surface.

[0088] The relative characteristics of the partial reflection regions 116 and 526 on the color conversion resonator cavity 118 are as follows: 44 is emitted from a first pixel associated with the partial reflection region 526 (for example, a pixel having dimensions 532 in Figure 5), and any converted light 744 having a second main peak wavelength and light having a first main peak wavelength pass through the partial reflection region 116, thereby enabling efficient reuse of light within the portion of the color conversion resonator system 600.

[0089] Therefore, in the regions associated with the second and third pixels (for example, the regions associated with pixel dimensions 534 and 536 in Figure 5), light 744 of the second principal peak wavelength is received in the color conversion resonator cavity 114 through the partial reflection region 116. Light 742 of the first principal peak wavelength that was not converted is also received in the color conversion resonator cavity 114.

[0090] The light 742 with the first principal peak wavelength and the light 744 with the second principal peak wavelength are at least partially converted to the light 746 with the third principal peak wavelength within the color conversion resonator cavity 114. In the example in Figure 6, the third principal peak wavelength corresponds to green light.

[0091] Light 746 at the third main peak wavelength resonates within the color conversion resonator cavity 114 and is transmitted through the partial reflection region 112. Light 746 at the third main peak wavelength is also transmitted through a second further partial reflection region 528 and emitted.

[0092] In the second pixel (for example, the pixel associated with pixel dimension 534 in Figure 5), light 746 of the third principal peak wavelength is transmitted through a second further partial reflection region 528 and emitted. In the third pixel (for example, the pixel associated with pixel dimension 536 in Figure 5), light 742 of the first principal peak wavelength, light 744 of the second principal peak wavelength, and light 746 of the third principal peak wavelength are received in the color conversion resonator cavity 110 through the partial reflection region 112. Light 746 of the third principal peak wavelength is converted into light 748 of the fourth principal peak wavelength in the color conversion resonator cavity 110. Light 748 of the fourth principal peak wavelength corresponds to red light.

[0093] Light 748 of the fourth principal peak wavelength resonates within the color conversion resonator cavity 110, is transmitted through the partial reflection region 108 and / or a third further partial reflection region 530, and is emitted.

[0094] Preferably, the input light 742 with the first main peak wavelength has a wavelength corresponding to ultraviolet (UV) light. Alternatively, or in addition, the input light 742 with the first main peak wavelength has a wavelength corresponding to blue light. In further examples, different wavelengths of light are used.

[0095] While a system demonstrating color conversion for providing blue, green, and red converted light outputs is explicitly shown, in further examples, blue light is used as the first primary peak wavelength. Advantageously, when red, green, and blue light outputs are desired, one of the color conversion resonator cavities and associated partial reflecting layers do not need to be used.

[0096] The input light 742 with the first main peak wavelength has a wavelength corresponding to UV wavelength light. The converted light 744 with the second main peak wavelength corresponds to blue wavelength light, thereby causing the first pixel to emit blue light. The converted light 746 with the third main peak wavelength corresponds to green wavelength light, thereby causing the second pixel to emit green light. The converted light 748 with the fourth main peak wavelength corresponds to red wavelength light, thereby causing the third pixel to emit red light. Such embodiments enable the monolithic integration of red, green, and blue pixels to provide a monolithic color conversion system.

[0097] In some examples, the first, second, and third pixels are isolated and individually addressable by the CMOS backplane 602, thereby enabling the formation of a multi-color light-emitting display.

[0098] Figure 6 shows LED 224, but in further examples, individual light-emitting diodes are used to selectively provide light to a light-emitting surface associated with a specific color-converting resonator cavity and associated output light. Figure 7 shows an alternative embodiment of the color-converting resonator system 700. The color-converting resonator system 700 comprises a first LED 224, a second LED 638, and a third LED 640. LEDs 224, 638, and 640 are arranged adjacent to each other. Layers 222, 120, 118, 116, 114, 112, 110, 108, 526, 528, and 530 are grown sequentially on LEDs 224, 638, and 640 to form a selectively etched configuration of the color-converting resonator system 500.

[0099] The first LED 224 is bonded so that the input light from the first LED 224 is supplied to a first pixel having pixel dimensions 532; the second LED 638 is bonded so that the input light from the second LED 638 is supplied to a second pixel having pixel dimensions 534; and the third LED 640 is bonded so that the input light from the third LED 640 is supplied to a third pixel having pixel dimensions 536. The LEDs 224, 638, and 640 are bonded to the color conversion resonator cavity system according to the techniques described herein with reference to Figures 1 to 6. The LEDs 224, 638, and 640 are individually addressable LED devices that can be addressed using a suitable backplane, such as a Si-based CMOS backplane.

[0100] Advantageously, the color conversion resonator system 700 enables controlled light emission from each of the three pixels individually. The improved angular distribution, intensity, and color purity shown herein provide significant benefits, particularly with respect to augmented reality applications where a high-resolution array of LEDs is used to form a display very close to the user. Furthermore, advantageously, using epitaxially grown layers to form the color conversion resonator cavity system means that the size constraints imposed by quantum dot-based color conversion systems can be overcome, potentially providing a smaller light-emitting surface for micro-LED-based light-emitting pixels and an array of light-emitting pixels with a reduced pixel pitch.

[0101] Figures 1 to 7 show epitaxially grown color-converting resonator systems formed by sequential growth of layers on a substrate, but in further examples, a series of layers are grown epitaxially and then bonded to another series of epitaxial layers. Advantageously, this method allows for the independent optimization and bonding of individual color-converting resonator cavities, or groups of color-converting resonator cavities, to each other, thereby providing high-crystal-quality color-converting resonator cavities optimized for their specific wavelengths of resonant light.

[0102] Figure 8 shows an alternative embodiment of the color conversion resonator system 800. The color conversion resonator system 800 comprises a color conversion resonator cavity 118 that is epitaxially grown on a partial reflection region 120 and then bonded to an input LED 224 and a substrate device 202 via a bonding layer 222. On this series of layers, a partial reflection region 116 and a color conversion resonator cavity 114 are bonded via a bonding layer 850. In addition, on this series of layers, a partial reflection region 112, a color conversion resonator cavity 110, and optionally a partial reflection region 108 are bonded via a bonding layer 852. Substantially, each color conversion resonator cavity 110, 114, 118 and its respective partial reflection region are provided separately and bonded to each other to form the structure of Figure 8. Advantageously, each color conversion resonator cavity 110, 114, 118 and its respective partial reflection region can be individually optimized before being bonded to each other to form the final structure. Such individual optimizations mean, for example, that blue and green light-emitting structures may be formed based on nitride materials, while red light-emitting structures may be formed using different materials, such as phosphide materials. In further examples, different combinations of materials are used to provide structures optimized for color conversion and resonance at specific frequencies of light.

[0103] LED224 is bonded to the partial reflection region 120 using a dielectric junction. The surface of LED224 that will be bonded to the partial reflection region 120 is terminated with a high-density oxide film to facilitate such bonding. The surface of the partial reflection region 120 that will be bonded to the input LED224 is also terminated with a high-density oxide film to facilitate wafer-level oxide bonding. Therefore, the main light-emitting surface of LED224 is positioned in close proximity to, or in contact with, the partial reflection region 120 so that the light output from LED224 serves as the input light for the color conversion resonator system 800. Similarly, the color conversion resonator cavity 118 and the partial reflection region 116 are terminated with a high-density oxide film to facilitate wafer-level oxide bonding. In addition, the color conversion resonator cavity 114 and the partial reflection region 112 are terminated with a high-density oxide film to facilitate wafer-level oxide bonding.

[0104] In a further example, the LED 224 is bonded to the partial reflection region 120 using a polymer bond, such as a polyimide bond. Similarly, the color conversion resonator cavity 118 is bonded to the partial reflection region 116 using a polymer bond, such as a polyimide bond. Furthermore, the color conversion resonator cavity 114 is bonded to the partial reflection region 112 using a polymer bond, such as a polyimide bond. In a further example, additional or alternative bonding mechanisms are used to attach the corresponding layers. Advantageously, the layers are bonded to form a single device with minimal interfacial loss of light emission from the LED 224 at the interface with the color conversion resonator system 800.

[0105] In Figure 8, the layers are shown to be joined using bonding layers 222, 850, and 852, but in further examples, additional and / or alternative bonding layers are used to form structure 800 in Figure 8.

[0106] Figure 9 shows a color conversion resonator system 900 comprising an LED 224, a bonding layer 222, a partial reflection region 120, a color conversion resonator cavity 118, a bonding layer 850, a further partial reflection region 116, and a further color conversion resonator cavity 114. Each of these layers is grown sequentially and then bonded, as described above in Figure 8. On this series of layers, layers partially etched from the structure described with respect to Figure 8 are shown. The etched layers are the bonding layer 852, the partial reflection region 112, the color conversion resonator cavity 110, and the partial reflection region 108. These layers were etched such that layers 108, 110, and 112, and 852 form a partial overlap region with the remaining layers 224, 222, 120, 118, 850, 116, and 114.

[0107] In a further example, the color conversion resonator system 900 is provided by joining already etched layers to provide a partial overlap region. For example, an array of etched layers is provided and joined together to provide a partial overlap region corresponding to different optical output wavelengths.

[0108] Figure 10 shows a color conversion resonator system 1000 comprising an LED 224, a bonding layer 222, a partial reflection region 120, and a color conversion resonator cavity 118. As described above, these layers, which are grown sequentially and bonded, remain unetched. On the layers 224, 222, 120, and 118 are a bonding layer 850, a partial reflection region 116, and a further color conversion resonator cavity 114. The bonding layer 850, the partial reflection region 116, and the color conversion resonator cavity 114 were selectively etched such that layers 114, 116, and 850 form a partial overlap region with the remaining layers 224, 222, 120, and 118. As described above, on layers 114, 116, and 850 there is a bonding layer 852, a further partial reflection region 112, a further color conversion resonator cavity 110, and a further partial reflection region 108, thereby the layers 852, 112, 110, and 108 are on layers 114, 116, and A partial overlap region is formed with 850. The use of an etch stop (not shown) between the color conversion resonator cavity 118 and the bonding layer 850 facilitates control of material removal by etching. A second etch process forms an exposed light-emitting surface region associated with the color conversion resonator cavity 114 and an exposed light-emitting surface region associated with the color conversion resonator cavity 118. In a further example, the color conversion resonator system 1000 is provided by bonding already etched layers to provide a partial overlap region. For example, an array of etched layers is provided and bonded to each other to provide a partial overlap region corresponding to different light output wavelengths.

[0109] Figure 11 shows a color-converting resonator system 1100, in which the color-converting resonator system 1000 described with reference to Figure 10 is further modified to provide a first further partial reflection region 526, a second further partial reflection region 528, and a third further partial reflection region 530. The third further partial reflection region 530 associated with the color-converting resonator cavity 110 is provided in place of the partial reflection region 108 formed within the initial epitaxial structure. Alternatively, the partial reflection region 108 remains in place, and the third further partial reflection region 530 is not formed within the structure shown in Figure 11. The first further partial reflection region 526 is formed on the exposed surface of the color-converting resonator cavity 118. The second further partial reflection region 528 is formed on the exposed surface of the color-converting resonator cavity 114.

[0110] Although LED224 is shown as a single LED, in further examples, LED224 is formed from individually addressable LED devices, each corresponding to the light output in one or more pixels formed from a partially overlapping region of the color conversion resonator system 1100. In this way, a high-resolution display can be formed.

[0111] In further examples, different combinations of cavities are grown together and then joined to each other. For example, chromatic resonator cavities 118 and 114 can be grown together with partial reflection regions 120 and 116 in one step. These epitaxially grown layers can then be joined to chromatic resonator cavities 110 and partial reflection regions 112 and 108 via a bonding layer. Advantageously, such a process allows chromatic resonator cavities 118 and 114 to be grown from similar materials, providing high-quality cavities, while chromatic resonator cavities 110 can be grown from different materials that are more optimal for the wavelengths of light required within the chromatic resonator cavities 110. For example, chromatic resonator cavities 118 can correspond to blue wavelength light, and chromatic resonator cavities 114 can correspond to green wavelength light. Therefore, it may be optimal to grow chromatic resonator cavities 118 and 114 together from a nitride-based material. The color conversion resonator cavity 110 can respond to red wavelength light. Therefore, it may be optimal to grow the color conversion resonator cavity 110 separately from a phosphide-based material.

[0112] To facilitate the bonding process described with reference to Figures 8 to 11, a working wafer or growth substrate is used for each individual component and removed at an appropriate stage in the device fabrication process.

[0113] Therefore, the color conversion resonator system 1100 can be used to provide an array of pixels, such as a high-resolution micro-LED array of pixels emitting light of different wavelengths, in a manner similar to that described with the color conversion resonator systems in Figures 1 to 7.

[0114] Methods for forming a color conversion resonator system have been described above with reference to Figures 1 to 11, but those skilled in the art will understand that in further examples additional or alternative steps are used, and in even further examples some steps are omitted. In further examples, one or more LED structures are provided that are combined with one or more color conversion resonator cavities, resulting in improved luminescence characteristics as described herein, while the order of the processing steps is changed. It can be done.

Claims

1. A color conversion resonator system, A first partial reflection region configured to transmit light of a first principal peak wavelength and reflect light of a second principal peak wavelength, A second partially reflective region configured to at least partially transmit light of the first and second main peak wavelengths and reflect light of the third main peak wavelength, A third partial reflection region configured to at least partially reflect light having the third main peak wavelength, A first color conversion resonator cavity configured to receive input light having a first principal peak wavelength through a first partial reflection region, convert at least a portion of the input light having the first principal peak wavelength, and provide light of a second principal peak wavelength, wherein the first color conversion resonator cavity is configured such that the second principal peak wavelength resonates within the first color conversion resonator cavity and resonant light having the second principal peak wavelength is output through a second partial reflection region, A color conversion resonator system comprising: a second color conversion resonator cavity configured to receive input light including the second principal peak wavelength through the second partial reflection region, convert at least a portion of the second principal peak wavelength, and provide light of the third principal peak wavelength, wherein the second color conversion resonator cavity is configured such that the third principal peak wavelength resonates within the second color conversion resonator cavity and resonant light having the third principal peak wavelength is output through the third partial reflection region, wherein the first color conversion resonator cavity and the second color conversion resonator cavity are configured to partially overlap, non-overlapping portions and overlapping portions, thereby defining a first light-emitting surface and a second light-emitting surface, respectively, wherein the first light-emitting surface is configured to provide resonant light of the second principal peak wavelength and the second light-emitting surface is configured to provide resonant light of the third principal peak wavelength.

2. The color conversion resonator system according to claim 1, wherein the color conversion resonator system is a monolithic color conversion system.

3. The first partial reflection region and the second partial reflection region are (N+1) λ ｃｏｎｖｅｒ ｔｅｄ / 2n(λ ｃｏｎｖｅｒｔｅｄ ) is separated by a distance that is multiplied by, where N is a positive integer and λ ｃｏｎｖｅｒｔｅｄ is the second main peak wavelength, and n(λ ｃｏｎｖｅｒｔｅｄ ) is the effective refractive index of the material separating the first partial reflection region and the second partial reflection region, thereby defining the length of the first color conversion resonator cavity, and / or the second partial reflection region and the third partial reflection region are separated by a distance that is multiplied by (N + 1)λ' ｃｏｎｖｅｒｔｅｄ / 2n(λ' ｃｏｎｖｅｒｔｅｄ ), where N is a positive integer and λ' ｃｏｎｖｅｒｔｅｄ is the third main peak wavelength, and n(λ' ｃｏｎｖｅｒｔｅｄ ) is the effective refractive index of the material separating the second partial reflection region and the third partial reflection region, thereby defining the length of the second color conversion resonator cavity. The color conversion resonator system according to claim 1 or 2.

4. The color conversion resonator system according to any one of claims 1 to 3, wherein the color conversion resonator system comprises at least one LED.

5. The color conversion resonator system according to claim 4, further comprising: a first LED configured to control light emission from the first light-emitting surface; and a second LED configured to control light emission from the second light-emitting surface.

6. The third partial reflection region is further configured to reflect light having a fourth principal peak wavelength, and the color conversion resonator system is configured A fourth partial reflection region configured to at least partially reflect light having the fourth main peak wavelength, A third color conversion resonator cavity is configured to receive input light including the third principal peak wavelength through the third partial reflection region, convert at least a portion of the third principal peak wavelength, and provide light of the fourth principal peak wavelength, wherein the third color conversion resonator cavity is configured such that the fourth principal peak wavelength resonates within the third color conversion resonator cavity and resonant light having the fourth principal peak wavelength is output through the fourth partial reflection region, and the third and fourth partial reflection regions are λ'' in (N+1). ｃｏｎｖｅｒｔｅｄ / 2n(λ'' ｃｏｎｖｅｒｔｅｄ The distance is determined by multiplying by ), where N is a positive integer and λ'' ｃｏｎｖｅｒｔｅｄ is the fourth main peak wavelength, and n(λ'') ｃｏｎｖｅｒｔｅｄ ) is the effective refractive index of the material separating the third partial reflection region and the fourth partial reflection region, thereby defining the length of the third color conversion resonator cavity, the third color conversion resonator cavity, A color conversion resonator system according to any one of claims 1 to 5, further comprising:

7. The color conversion resonator system according to claim 6, wherein the second color conversion resonator cavity and the third color conversion resonator cavity are configured to partially overlap, provide non-overlapping portions and overlapping portions, thereby defining the second light-emitting surface and the third light-emitting surface, respectively, wherein the second light-emitting surface is configured to provide resonant light of the third principal peak wavelength, and the third light-emitting surface is configured to provide resonant light of the fourth principal peak wavelength.

8. The color conversion resonator system according to any one of claims 1 to 7, wherein the first color conversion resonator cavity includes at least one quantum well layer, the at least one quantum well layer is positioned to coincide with a wave antinode of the standing wavelength of the first color conversion resonator cavity for the conversion light, thereby improving at least one of the intensity, spectral width, and directivity of output light having a resonant conversion wavelength of light.

9. The second color conversion resonator cavity includes at least one quantum well layer, the at least one quantum well layer being positioned to coincide with a wave antinode of the standing wavelength of the second color conversion resonator cavity for the converted light, thereby enabling the output light having the resonant converted wavelength of the light, spectrum A color conversion resonator system according to any one of claims 1 to 7, which improves at least one of the cricket width and directivity.

10. The color conversion resonator system according to claim 8, wherein at least one of the first color conversion resonator cavity and the second color conversion resonator cavity includes at least one absorbing layer configured to absorb input light, thereby enabling the transfer of energy from the input light into the at least one quantum well layer, the absorbing layer comprising a material having an energy bandgap lower than the energy of the input light.

11. At least one of the first color conversion resonator cavity and the second color conversion resonator cavity includes a quantum well layer containing one or more quantum wells, and a further quantum well layer containing one or more quantum wells, wherein the separation of the quantum well layer and the further quantum well layer is λ''' to N ｃｏｎｖｅｒｔｅｄ / 2n(λ''' ｃｏｎｖｅｒｔｅｄ This is the result of multiplying by ), where N is a positive integer and λ''' ｃｏｎｖｅｒｔｅｄ n(λ'') is the wavelength of the resonant light in at least one of the color-converting resonator cavities, which is one of the first color-converting resonator cavities and the second color-converting resonator cavities, where n(λ'') ｃｏｎｖｅｒｔｅｄ The color conversion resonator system according to any one of claims 1 to 10, wherein ) is the effective refractive index of the material between the quantum well layer and the further quantum well layer at the wavelength of the resonant light in at least one of the color conversion resonator cavities, the first color conversion resonator cavity and the second color conversion resonator cavity.

12. The color conversion resonator system according to any one of claims 1 to 11, further comprising at least one further partial reflection region corresponding to at least one of the first and second light-emitting surfaces.

13. The color conversion resonator system according to any one of claims 1 to 12, wherein at least one of the first partial reflection region, the second partial reflection region, the third partial reflection region and / or the further partial reflection region includes a distributed Bragg reflector, the distributed Bragg reflector being at least one of a dual-band distributed Bragg reflector, a conventional distributed Bragg reflector, and a vertical stack of two distributed Bragg reflectors.

14. The color conversion resonator system according to any one of claims 1 to 13, wherein at least one of the first partial reflection region, the second partial reflection region, the third partial reflection region, the first color conversion resonator cavity, and the second color conversion resonator cavity includes an epitaxial crystal layer, and the color conversion resonator system includes at least one of a dielectric material and a III-V semiconductor material.

15. An array of pixels comprising the color conversion resonator system according to any one of claims 1 to 14.

16. The array according to claim 15, wherein the array comprises a first pixel configured to emit light of a different wavelength than the second pixel, and the first and / or second pixel includes a further partial reflection region corresponding to its light-emitting surface.

17. The pixel array according to claim 16, further comprising a third pixel configured to emit light of a different wavelength than the first pixel and the second pixel.

18. A method for forming a color conversion resonator system according to any one of claims 1 to 14.

19. The method according to claim 18, comprising forming at least one of the first color conversion resonator cavity and the second color conversion resonator cavity on a substrate.

20. The method according to claim 19, wherein forming at least one of the first color conversion resonator cavity and the second color conversion resonator cavity on the substrate includes the epitaxial growth of a plurality of layers.

21. The method according to claim 20, comprising forming at least one of the first partial reflection region, the second partial reflection region, and the third partial reflection region on the substrate, wherein forming at least one of the first partial reflection region, the second partial reflection region, and the third partial reflection region on the substrate comprises sequentially forming at least one of the first color conversion resonator cavity, the second color conversion resonator cavity, the first partial reflection region, the second partial reflection region, and the third partial reflection region on the substrate.

22. The method according to any one of claims 18 to 21, comprising joining the color conversion resonator system to at least one LED.

23. The method according to any one of claims 18 to 22, comprising joining two or more of the first partial reflection region, the second partial reflection region, the third partial reflection region, the first color conversion resonator cavity, and the second color conversion resonator cavity to each other.

24. The method according to any one of claims 18 to 22, comprising selectively etching the color conversion resonator system to provide the first light-emitting surface and the second light-emitting surface.

Images