Engineered scattering in LED encapsulant for tunable optical far field response

Abstract

A light engine having distinct light sources sharing at least one optical device may employ scattering particles to alter the brightness line profile of one or more light sources such that they are more uniformly mixed in the far field. The scattering particles may be integrated into a phosphor layer of a particular light source, or may be disposed in a separate layer. The scattering particles may be tunable based on specific characteristics of the light source, such as their spectral characteristics or their chemical mixing characteristics.

Description

[0001] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] This invention was made with government support under DE-EE0009167 awarded by the U.S. Department of Energy. The government has certain rights in this invention.

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims the benefit of priority to U.S. Provisional Application No. 63 / 355,483, filed on June 24, 2022, which is incorporated by reference in its entirety into this application. Technical Field

[0005] The present disclosure generally relates to LEDs, pcLEDs, LED arrays and pcLED arrays, light sources including LEDs, pcLEDs, LED arrays or pcLED arrays, and displays including LEDs or pcLED arrays. In particular, the present disclosure relates to methods and devices for integrating phosphors into semiconductor light emitting diodes. Background Art

[0006] Semiconductor light emitting diodes and laser diodes (collectively referred to herein as "LEDs") are among the most efficient light sources currently available. The emission spectrum of an LED typically exhibits a single narrow peak at a wavelength determined by the structure of the device and the composition of the semiconductor material from which it is constructed. By appropriately selecting the device structure and material system, an LED can be designed to operate at ultraviolet, visible, or infrared wavelengths.

[0007] The LED can be combined with one or more wavelength conversion materials (generally referred to herein as "phosphors") that absorb light emitted by the LED and emit longer wavelength light in response. For such a phosphor-converted LED ("pcLED"), the fraction of light emitted by the LED that is absorbed by the phosphor depends on the amount of phosphor material in the optical path of the light emitted by the LED, for example, on the concentration of phosphor material in a phosphor layer disposed on or around the LED and the thickness of the layer. The phosphor-converted LED can be designed so that all light emitted by the LED is absorbed by one or more phosphors, in which case the emission from the pcLED is entirely from the phosphor. In this case, for example, the phosphor can be selected to emit light in a narrow spectral region that is not directly and efficiently generated by the LED. Alternatively, the pcLED can be designed so that only a portion of the light emitted by the LED is absorbed by the phosphor, in which case the emission from the pcLED is a mixture of light emitted by the LED and light emitted by the phosphor. By appropriately selecting the LED, phosphor, and phosphor composition, such a pcLED can be designed to emit, for example, white light having a desired color temperature and desired color rendering properties.

[0008] Technical and commercial applications of LEDs and pcLEDs include use in displays, matrices, and light engines, including: automotive adaptive headlights, augmented reality (AR) displays, virtual reality (VR) displays, mixed reality (MR) displays, smart glasses, and displays for mobile phones, smart watches, monitors, and televisions, as well as flash lighting for cameras in mobile phones. For example, the backlighting of liquid crystal displays typically employs pcLEDs that include a combination of green and red phosphors. Individual LEDs or pcLEDs in these architectures can have an area of ​​a few square millimeters to a few square micrometers (microLEDs).

[0009] LEDs and pcLEDs are used in luminaires or light engines, which provide lighting for general purposes, such as to illuminate a room. Light engines typically combine spectrally distinct light sources together, mixing them into a uniform beam, in order to provide light of the appropriate color and intensity. Primary optics may be used in these light engines to mix these light sources in the far field. However, in order to obtain a suitable uniform mix, these light engines may also need to utilize additional secondary optics in addition to the primary optics, in order to accommodate the different scattering profiles of the various light sources within the light engine. This may be necessary whether the light engine utilizes segmented LEDs of different colors, or phosphor-converted LEDs versus direct-emitting LEDs. These secondary optics are bulky, and adding them to the light engine is undesirable. What is needed is a better solution that similarly allows different light sources to be mixed into a uniform beam in the far field. Summary of the invention

[0010] Embodiments of the present invention include methods and devices for combining different light sources to achieve uniform mixing of the different light sources in the far field. In particular, a light engine having spectrally distinct light sources that share at least one optical device can employ scattering particles to broaden or narrow the brightness line profile of one or more light sources so that the light sources are uniformly spatially mixed in the far field. The scattering particles can be integrated into the phosphor layer of a particular light source, or can be disposed in a separate layer. The scattering particles can be disposed above some or all of the light sources and can be adjustable based on the specific characteristics, spectral or other characteristics of the light source.

[0011] Additional aspects and advantages of the present disclosure will be readily apparent to those skilled in the art from the following detailed description, wherein only illustrative embodiments of the present disclosure are shown and described. As will be appreciated, the present disclosure is capable of other and different embodiments, and its several details are capable of modification in various obvious respects, all without departing from the present disclosure. Therefore, the drawings and descriptions are to be regarded as illustrative in nature, and not restrictive. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic cross-sectional view of an example pcLED is shown.

[0013] Figure 2A and Figure 2B A schematic cross-sectional view and a top view of a pcLED array are shown, respectively.

[0014] Figure 3A shows a schematic top view of an electronic board on which a pcLED array may be mounted, and Figure 3B Similarly, the installation Figure 3A pcLED array on an electronic board.

[0015] Figure 4A A schematic cross-sectional view of a pcLED array arranged relative to a waveguide and projection lens is shown. Figure 4B shows the difference between the case without waveguide and Figure 4A The arrangement is similar to the arrangement of .

[0016] Figure 5 An example camera flash system is schematically shown.

[0017] Figure 6 An example display (e.g., AR / VR / MR) system is schematically illustrated.

[0018] Figure 7 A cross-sectional view of a light emitting device having a first light emitting array and a second light emitting array including scattering particles is shown.

[0019] Figure 8 A cross-sectional view of a light emitting device having a first light emitting array including scattering particles and a second light emitting array including scattering particles is shown.

[0020] Fig. 9 A cross-sectional view of a light emitting device is shown having a first light emitting array including scattering particles and a second light emitting array including a scattering particle layer without a phosphor layer.

[0021] Fig.10 A cross-sectional view of a light emitting device is shown having a first light emitting array with phosphor particles and a second light emitting array without a phosphor layer, including a layer of scattering particles.

[0022] Fig.11 A cross-sectional view of a light emitting device having three light emitting arrays, each light emitting array having a phosphor layer including scattering particles therein is shown.

[0023] Fig.12A cross-sectional view of a light emitting device is shown, the light emitting device having: a first light emitting array having a scattering particle layer separated from a phosphor particle layer; and a second light emitting array having a scattering particle layer separated from the phosphor particle layer.

[0024] Fig.13 A cross-sectional view of a light emitting device is shown having a first light emitting array having a layer of spatially varying phosphor particles and a layer of spatially varying scattering particles.

[0025] Fig.14 The actual visual of a single pixel of three different colors turned on is shown, along with its corresponding brightness line profile.

[0026] Fig.15 The actual visual effect of turning on an array of pixels of three different colors is shown, along with their corresponding brightness line profiles. DETAILED DESCRIPTION

[0027] The following detailed description should be read with reference to the accompanying drawings, wherein the same reference numerals refer to similar elements throughout the different figures. The drawings, which are not necessarily to scale, depict selective embodiments and are not intended to limit the scope of the invention. The detailed description illustrates the principles of the invention by way of example, not by way of limitation.

[0028] Figure 1 An example of an individual pcLED 100 is shown, which includes a light emitting semiconductor diode (LED) structure 102 disposed on a substrate 104, and a phosphor layer 106 (also referred to herein as a wavelength conversion structure) disposed on the LED. The light emitting semiconductor diode structure 102 generally includes an active region disposed between an n-type layer and a p-type layer. Application of a suitable forward bias voltage to the diode structure results in emission of light from the active region. The wavelength of the emitted light is determined by the composition and structure of the active region.

[0029] For example, the LED may be a Group III nitride LED that emits ultraviolet, blue, green, or red light. LEDs formed from any other suitable material system and emitting any other suitable wavelength of light may also be used. Other suitable material systems may include, for example, Group III phosphide materials, Group III arsenide materials, and Group II-IV materials.

[0030] Any suitable phosphor material may be used, depending on the desired optical output and color specifications for the pcLED.The phosphor layer may, for example, comprise phosphor particles dispersed in or bonded to one another with a binder material, or may be or comprise a sintered ceramic phosphor plate.

[0031] Figure 2A-2BA cross-sectional view and a top view are shown, respectively, of an array 200 of pcLEDs 100 including a phosphor layer 106 disposed on a substrate 202. Such an array may include any suitable number of pcLEDs arranged in any suitable manner. In the illustrated example, the array is depicted as being monolithically formed on a shared substrate, but alternatively, the pcLED array may be formed of individual mechanically separated pcLEDs disposed on a substrate. The substrate 202 may optionally include CMOS circuitry for driving the LEDs, and may be formed of any suitable material.

[0032] although Figure 2A-2B A three-by-three array of nine pcLEDs is shown, but such an array may include, for example, tens, hundreds, or thousands of LEDs. The width (e.g., side length) of each LED in the plane of the array may be, for example, less than or equal to 1 millimeter (mm), less than or equal to 500 microns, less than or equal to 100 microns, or less than or equal to 50 microns. The LEDs in such an array may be separated from each other by streets or lanes having a width in the plane of the array of, for example, hundreds of microns, less than or equal to 100 microns, less than or equal to 50 microns, less than or equal to 10 microns, or less than or equal to 5 microns.

[0033] LEDs having a dimension in the plane of the array (eg, a side length) less than or equal to about 50 microns are generally referred to as micro-LEDs, and an array of such micro-LEDs may be referred to as a micro-LED array.

[0034] Although the illustrated examples show rectangular LEDs or pcLEDs arranged in a symmetrical matrix, the LEDs or pcLEDs and arrays may have any suitable shape or arrangement and need not all be the same shape or size. For example, LEDs or pcLEDs located in the center portion of the array may be larger than LEDs or pcLEDs located in the peripheral portion of the array. Alternatively, LEDs or pcLEDs located in the center portion of the array may be smaller than LEDs or pcLEDs located in the peripheral portion of the array.

[0035] In a pcLED array, all pcLEDs can be configured to emit substantially the same spectrum of light. Alternatively, the pcLED array can be a multicolor array, where different pcLEDs in the array can be configured to emit different spectra (colors) of light by employing different phosphor compositions. Similarly, in an array of direct emitting LEDs (i.e., without wavelength conversion by a phosphor), all LEDs in the array can be configured to emit substantially the same spectrum of light, or the array can be a multicolor array that includes LEDs configured to emit different colors of light.

[0036] Individual LEDs or pcLEDs in the array may be individually operable (addressable) and / or may be operable as part of a group or subset of (eg, adjacent) LEDs or pcLEDs in the array.

[0037] An LED or pcLED array, or portions of such an array, can be formed as a segmented monolithic structure in which the individual LEDs or pcLEDs are electrically isolated from each other by trenches and / or insulating materials, but the electrically isolated segments are still physically connected to each other through portions of the semiconductor structure.

[0038] Thus, the LED or pcLED array may be or include a monolithic multicolor matrix of individually operable LED or pcLED light emitters.The LEDs or pcLEDs in the monolithic array may, for example, be micro-LEDs as described above.

[0039] A single individually operable LED or pcLED or a group of adjacent such LEDs or pcLEDs may correspond to a single pixel (picture element) in a display. For example, a group of three adjacent individually operable LEDs or pcLEDs including a red emitter, a blue emitter, and a green emitter may correspond to a single color-tunable pixel in a display.

[0040] like Figure 3A-3B As shown in FIG. 1 , the LED or pcLED array 200 can be mounted on an electronic board 300 that includes a power and control module 302, a sensor module 304, and an attachment area 306. The power and control module 302 can receive power and control signals from an external source and signals from the sensor module 304, and the power and control module 302 controls the operation of the LED / pcLED based on these signals. The sensor module 304 can receive signals from any suitable sensor (e.g., from a temperature or light sensor). Alternatively, the array 200 can be mounted on a board (not shown) separate from the power and control module and the sensor module.

[0041] Each LED or pcLED may optionally be combined or arranged in combination with a lens or other optical element positioned adjacent to or disposed on the phosphor layer. Such optical elements, not shown in the figures, may be referred to as "primary optical elements". Figure 4A-4B As shown in , the array 200 (e.g., mounted on an electronic board 300) can be arranged in combination with secondary optical elements (such as waveguides, lenses, or both) for use in the intended application. Figure 4A In FIG. 4 , light emitted by pcLED 100 is collected by waveguide 402 and directed to projection lens 404. For example, projection lens 404 may be a Fresnel lens. This arrangement may be suitable for use, for example, in a motor vehicle headlight. Figure 4BIn the embodiment of the present invention, the light emitted by the pcLED 100 is collected directly by the projection lens 404 without the use of an intervening waveguide. This arrangement may be particularly suitable when the LEDs or pcLEDs can be spaced sufficiently close to each other, and may also be used in automotive headlights and camera flash applications. For example, micro LED display applications may use a method similar to Figure 4A-4B An optical arrangement of the optical arrangement depicted in .

[0042] In another example arrangement, a center block of LEDs or pcLEDs in an array may be associated with a single common (shared) optic, and edge LEDs or pcLEDs in the array located at the periphery of the center block are each associated with a corresponding individual optic.

[0043] In general, any suitable arrangement of optical elements may be used in combination with the LED arrays and pcLED arrays described herein, depending on the desired application.

[0044] LED arrays and pcLED arrays as described herein can be used in applications that require or benefit from fine-grained intensity, spatial, and temporal control of light distribution. These applications can include, but are not limited to, precise special patterning of emitted light from individual LEDs or pcLEDs or from groups (e.g., blocks) of LEDs or pcLEDs. Depending on the application, the emitted light can be spectrally distinct, adaptive over time, and / or environmentally responsive. Such arrays can provide pre-programmed light distributions in various intensity, spatial, or temporal patterns. The emitted light can be based at least in part on received sensor data and can be used for optical wireless communications. The associated electronics and optics can be distinct at the individual LED / pcLED, group, or device level.

[0045] An array of independently operable LEDs or pcLEDs can be used in conjunction with a lens, a lens system, or other optical devices or optical systems (e.g., as described above) to provide lighting suitable for a particular purpose. For example, in operation, such an adaptive lighting system can provide lighting that changes color and / or intensity across the illuminated scene or object, and / or aims at a desired direction. The beam focusing or steering of the light emitted by the LED or pcLED array can be performed electronically by activating the LEDs or pcLEDs in groups of different sizes or activating the LEDs or pcLEDs in sequence to allow dynamic adjustment of the beam shape and / or direction without moving the optical device or changing the focus of the lens in the lighting device. The controller can be configured to receive data indicating the position and color characteristics of an object or person in the scene, and based on this information, control the LEDs or pcLEDs in the array to provide lighting suitable for the scene. Such data can be provided by, for example, an image sensor, an optical (e.g., laser scanning) sensor, or a non-optical (e.g., millimeter wave radar) sensor. Such adaptive lighting is increasingly important for motor vehicles (e.g., adaptive headlights), mobile device cameras (e.g., adaptive flash), VR and AR applications (such as those described below).

[0046] Figure 5 An example camera flash system 500 including an LED or pcLED array and a lens system 502 is schematically shown, which can be or include an adaptive lighting system as described above, in which the LEDs or pcLEDs in the array can be individually operable. In operation of the camera flash system, illumination from some or all of the LEDs or pcLEDs in the array and lens system 502 can be adjusted (disabled, operated at full intensity, or operated at intermediate intensities). As described above, the array can be a monolithic array, or include one or more monolithic arrays. As described above, the array can be a micro-LED array.

[0047] The flash system 500 also includes an LED driver 506 controlled by a controller 504, such as a microprocessor. The controller 504 may also be coupled to a camera 507 and a sensor 508, and operate according to instructions and profiles stored in a memory 510. The camera 507 and the LED or pcLED array and lens system 502 may be controlled by the controller 504, for example, to match the illumination provided by the system 502 (i.e., the field of view of the illumination system) to the field of view of the camera 507, or to otherwise adapt the illumination provided by the system 502 to the scene viewed by the camera as described above. The sensor 508 may include, for example, a position sensor (e.g., a gyroscope and / or accelerometer) and / or other sensors that may be used to determine the position and orientation of the system 500.

[0048] Figure 6An example display (e.g., AR / VR / MR) system 600 is schematically shown, which includes an array 610 of individually operable LEDs or pcLEDs, a display 620, a light array controller 630, a sensor system 640, and a system controller 650. As described above, the array 610 can be a monolithic array, or include one or more monolithic arrays. The array can be monochrome. Alternatively, the array can be a multi-color array, in which different LEDs or pcLEDs in the array are configured to emit light of different colors, as described above. Thus, the array can be or include a monolithic multi-color matrix of individually operable LED or pcLED light emitters, which can be, for example, micro-LEDs as described above. A single individually operable LED or pcLED in the array or a group of adjacent such LEDs or pcLEDs can correspond to a single pixel (picture element) in the display. For example, a group of three individually operable adjacent LEDs or pcLEDs including a red emitter, a blue emitter, and a green emitter can correspond to a single color-adjustable pixel in the display. The array 610 can be used to project light in a graphic pattern or an object pattern, which can support an AR / VR / MR system.

[0049] Control inputs are provided to the sensor system 640, while power and user data inputs are provided to the system controller 650. In some embodiments, the modules included in the system 600 may be compactly arranged in a single structure, or one or more elements may be mounted separately and connected via wireless or wired communications. For example, the array 610, display 620, and sensor system 640 may be mounted on a headset or glasses, with the light array controller and / or system controller 650 mounted separately.

[0050] System 600 may incorporate a variety of optics (not shown) to couple light emitted by array 610 into display 620. Any suitable optics may be used for this purpose.

[0051] Sensor system 640 may include, for example: external sensors to monitor the environment, such as cameras, depth sensors, or audio sensors; and internal sensors to monitor the position of the AR / VR / MR headset, such as accelerometers or two-axis or three-axis gyroscopes. Other sensors may include, but are not limited to, air pressure, strain sensors, temperature sensors, or any other suitable sensor required for local or remote environmental monitoring. In some embodiments, control inputs may include detected touches or taps, gesture inputs, or controls based on the position of the headset or display.

[0052] In response to data from the sensor system 640, the system controller 650 can send images or instructions to the light array controller 630. Changes or modifications to the images or instructions can also be made through user data input or automatic data input as needed. User data input can include, but is not limited to, data input provided by audio commands, tactile feedback, eye or pupil positioning, or a connected keyboard, mouse, or game controller.

[0053] The device as described above may include a reflective side coating on the light emitting elements. The reflective side coating optically isolates adjacent light emitting elements, thereby reducing crosstalk and increasing contrast between adjacent light emitting elements.

[0054] A device as described above may include different pixels or pcLEDs with different spectral characteristics, including colors. Different pixels or pcLEDs with different spectral characteristics may appear at different locations in the far field, or otherwise mix poorly, even when they are directed by the same optical element, such as projection lens 404. This may be problematic when a uniform beam in the far field is desired.

[0055] Figure 7 An embodiment of the present invention is shown in the form of a light emitting device 700 having a first array 702 and a second array 704, each having an optical element 715. The light emitting device 700 may be a light engine. The first array 702 includes an LED 710, a phosphor layer 720, and a first phosphor particle 752 in the phosphor layer. The second array 704 includes an LED 710, an integrated phosphor layer 722, and a second phosphor particle 762 and a second scattering particle 766 in the integrated phosphor layer. The first array 702 may emit a first light of a first color or color temperature, and the second array 704 may emit a second light of a second color or color temperature different from the first color or color temperature of the first light. For example, the first array 702 may emit red, blue, or green light, and the second array 704 may emit red, blue, or green light different from the first array 702. In another example, the first array 702 may emit a first light of a cool white color, and the second array 704 may emit a second light of a warm white color.

[0056] The first array 702 and the second array 704 may each have an optical element 715. The individual optical elements 715 may be arranged only in the optical path of their respective arrays, or they may be arranged only in the optical path of most or most of the light emitted from their respective arrays. The optical element 715 mixes the first light and the second light of the first and second arrays 702 and 704 so that they are spatially and spectrally uniformly mixed in the far field. For example, the far field may be Figure 7701 (at which the light rays depicted exiting the phosphor layer and passing through the optical element converge) such that only one optical element is required between the phosphor layer and the far field to mix evenly at the surface 701, and the optical element 715 can be a converging lens. As a result, the first light and the second light can be mixed to appear as or substantially appear as a single color beam in the far field, rather than two spatially and spectrally distinct beams. The individual optical elements 715 can be the same type of lens and the same size as each other, or they can be different types of lenses and / or different sizes from each other.

[0057] The first array 702 and the second array 704 both include LEDs 710. Each LED 710 can be associated with a single pixel in the array. Figure 7 , the first array 702 is depicted as having three visible pixels, and the second array 704 is depicted as having three visible pixels. Figure 7 The cross section depicted, the array can of course be an X by X two-dimensional grid of pixels / LEDs, such as a 3×3, 7×7, or 9×9 array of pixels / LEDs. The LEDs 710 can emit light of the same color as each other (e.g., blue light), although this is not required, and the first array 702 and the second array 704 can each include LEDs that emit light of different colors from each other. The first array 702 can have a phosphor layer 720 having first phosphor particles 752 that are different from the second phosphor particles 762 disposed in the integrated phosphor layer 722 of the second array 704. For example, the first phosphor particles 752 can absorb light of a first wavelength or a first wavelength range and emit light of a second wavelength or wavelength range, while the second phosphor particles 762 can absorb light of the first wavelength or wavelength range and emit light of a third wavelength or wavelength range. For example, the first phosphor particles 752 can absorb blue light emitted from the LED 710 and emit green light, while the second phosphor particles can absorb blue light emitted from the LED 710 and emit red light. In another example, the second phosphor particles can absorb the first wavelength of blue light emitted from the LED 710 and emit a second wavelength of blue light. The first phosphor particles 752 can be or include a different material from the second phosphor particles 762. They can have different shapes, densities and / or size distributions from each other. Alternatively, they can have the same shape and / or size distribution as each other.

[0058] The density of the first phosphor particles 752 of the phosphor layer 720 can be different from the density of the second phosphor particles 762 of the integrated phosphor layer 722. The different densities can be greater or less. This is because the first array 702 and the second array 704 are designed to emit different colors, so that the first phosphor particles 752 and the second phosphor particles 762 can have different distances in the color space between the light of the LED 710 and their corresponding output colors. Therefore, these different color space distances may require differences in the relative amounts of phosphor included in the phosphor layer 720 of the first array 702 relative to the phosphor included in the integrated phosphor layer 722 of the second array 704. If the phosphor layer 720 and the integrated phosphor layer 722 have the same form factor (i.e., the same size), then it must have a greater density to account for the increase in the amount of phosphor particles required to achieve the desired spectral characteristics of the emitted light. Hypothetically consider that if the integrated phosphor layer 722 of the second array 704 did not include the second scattering particles 766, the increased density of phosphor particles in one of the phosphor layers of the first array 702 or the second array 704 may result in greater scattering within that phosphor layer compared to the other.

[0059] If phosphor layer 720 and integrated phosphor layer 722 do not have different phosphor particle densities, one may have a larger form factor than the other in order to accommodate the difference in the amount of phosphor required. This may also result in increased scattering of one phosphor layer over the other.

[0060] In order to address the scattering differences between phosphor layers of different arrays, scattering particles can be integrated into the integrated phosphor layer 722. The integrated phosphor layer 722 can have a greater or lesser phosphor particle density than the phosphor layer 720, so that in the absence of the second scattering particles 766, light propagating through the integrated phosphor layer 722 can be more or less scattered than light propagating through the phosphor layer 720. The second scattering particles 766 normalize the scattering differences between the integrated phosphor layer 722 and the phosphor layer 720. That is, the second scattering particles 766 included in the integrated phosphor layer 722 can increase or decrease the scattering in the integrated phosphor layer 722, so that the phosphor layer 720 and the integrated phosphor layer 722 both have the same or substantially the same amount of scattering. In other words, the second scattering particles 766 can widen or narrow the line profile of the second array 704 to match or more closely match the line profile of the first array 702. As a result, the first light emitted by the first array 702 and the second light emitted by the second array 704 can be uniformly mixed by the optical element 715. Without the second scattering particles 766, the first light and the second light may have color and / or spatial separation in the far field even after propagating through the optical element 715. Fig.14 and Fig.15The line profiles of brightness in the near field without scattering particles are shown separately. The line profiles in the far field can be similar and / or proportional to the line profiles in the near field. In other words, the relative differences in spatial widths between arrays in the near field can be preserved in the far field, depending on the optical element through which the light propagates. Alternatively, the optical element can distort the line profiles so that the relative differences of the arrays in the far field are different from the relative differences in the near field. Fig.14 A green pcLED array, a red pcLED array, and a green pcLED array are shown, with one pixel in each array turned on. As can be seen, the line profiles for each of these pixels are different (taken from a cross section of the line superimposed on the actual pixel image) because they spread out at different widths from one another. For example, the width can be measured at the full width at half maximum or at the bottom of the line profile, although the width can be measured in any other position as well, since the differences in line profiles between pixels are caused by scattering of phosphors of different colors and / or different compositions. Fig.15 The same array is shown with all pixels turned on. The line profiles of each of these arrays are also different. As a result of these differences, for example, in the absence of the second scattering particles 766, the light emitted from the light emitting device 700 may show color rings. Alternatively, in addition to the optical element 715, the light emitted from the light emitting device 700 may require additional complex and / or bulky optical elements to eliminate the color rings in the absence of the second scattering particles 766. When the scattering particles are included in one or more phosphor layers, the color rings can be eliminated from the emitted light beam so that only solid circles of a single color are visible in the far field without the additional use of more optical elements. In other words, the scattering profiles of light sources of different colors within the light engine can be standardized. Once it has been standardized, the brightness profile in the far field for a single pixel can be the same or substantially the same between light sources or arrays of different colors. That is, the brightness profiles of different arrays can have the same or substantially the same spatial width at each point, so that the curves of the line profiles overlap perfectly or nearly perfectly.

[0061] The presence, composition, transparency, refractive index, shape, density, and / or other similar characteristics of the scattering particles in some or all of the phosphor layers of the light emitting device 700 can be adjusted based on the desired brightness profile of the light emitting device 700 and the specific colors emitted from various arrays of light emitting devices 700. The type and amount of scattering particles can be selected based on the specific goals and elements of each light emitting device 700.

[0062] Scattering particles can be any particles that can achieve an adjustable increase in scattering without significant optical loss. They can be particles with high transparency and high refractive index. For example, they can be particles composed entirely of or including aluminum oxide, titanium dioxide or glass. Scattering particles can change the trajectory of light incident on them and may not change the wavelength of light incident on them. For example, the scattering particles can be non-phosphorescent, although this is not required. The scattering particles can be a different size and / or material than the phosphor particles.

[0063] The scattering particles may also be adjustable for mixing into the phosphor layer. That is, the size of the scattering particles may be adjustable to mix with the phosphor particles in the phosphor layer without size segregation. For example, the second scattering particles 766 may be selected to have a size distribution that is the same or substantially the same as the size distribution of the second phosphor particles 762 in the integrated phosphor layer 722. In addition, the scattering particles may undergo surface functionalization. Silane or other functional molecules may be applied to the surface of each scattering particle so that it becomes more energetically advantageous in the binder of the phosphor layer, and the scattering particles and the phosphor particles will be suspended in the binder. This surface functionalization improves the mixing of the scattering particles with the phosphor particles. In both the phosphor layer 720 and the integrated phosphor layer 722, the first phosphor particles 752 and the second phosphor particles may be uniformly arranged in their respective layers, for example, spatially uniform from one pixel to another, and / or spatially uniform when a length scale longer than the wavelength of light emitted from the LED 710 is considered. The second scattering particles 766 can also be uniformly disposed within the integrated phosphor layer 722. Additionally, deaggregation and / or two-phase mixing can be used to help form an integrated phosphor layer with scattering particles.

[0064] The phosphor layer may include a binder in which the phosphor particles and / or scattering particles may be suspended. The binder may be organic or inorganic and may be transparent. The binder may match the refractive index of the phosphor particles and / or scattering particles, or they may have different refractive indices. For example, the binder may be silicone, aluminum oxide, and / or other similar materials.

[0065] Figure 8An embodiment of the present invention is shown in the form of a light emitting device 700 having a first array 702 having an integrated phosphor layer 722 with first scattering particles 756 and a second array 704 having an integrated phosphor layer 720 with second scattering particles 766. In this case, the scattering particles are included in both the first array 702 and the second array 704. The first scattering particles 756 can have a different composition, density, size and / or shape than the scattering particles 762. For example, if the first phosphor particles 752 have a different size distribution than the second phosphor particles 762, the first scattering particles 756 can be selected to have a different size distribution than the second scattering particles, for example, a size distribution that matches or substantially matches the size distribution of the first phosphor particles 752. The first scattering particles 756 can cause greater or less scattering than the second scattering particles 766. For example, the first scattering particles 756 can narrow the line profile width of the pixel brightness from the first array 702, while the second array 704 can widen the line profile width of the corresponding pixel brightness from the second array 704, so that the corresponding pixel brightness from the first and second arrays 702 have matching line profiles. Alternatively, the first scattering particles 756 can widen the line profile width of the pixel brightness from the first array 702, while the second array 704 can narrow the line profile width of the corresponding pixel brightness from the second array 704, so that the corresponding pixel brightness from the first and second arrays 702 have matching line profiles.

[0066] Fig. 9An embodiment of the present invention is shown in the form of a light emitting device 700 having a first array 702 having an integrated phosphor layer 722 with first scattering particles 756 and a second array 704 having no phosphor layer but having a scattering layer 724 with third scattering particles 786. The second array 704 may be a direct emission array designed to emit light from an LED 710 without phosphor conversion. For example, the second array 704 may be designed to emit blue light from the LED 710. In any case, the line profile of the brightness from the light emitted by the second array 704 may need to be widened or narrowed in order to match the light emitted from the first array 702. For example, the first scattering particles 756 may widen the line profile of the first array 702, while the third scattering particles 786 narrow the line profile of the second array 704, or vice versa. Alternatively, both the first scattering particles 756 and the third scattering particles 786 may narrow the line profiles of their respective arrays, or may widen the line profiles of their respective arrays. In this case, the narrowing or widening effect of the first scattering particles relative to the third scattering particles may be different from each other. This arrangement may be desired if a specific line profile for the light emitting device 700 is desired outside the range of line profiles defined by the natural line profiles of the first and second arrays 702, 704 without the first and third scattering particles 756, 786. In other words, the scattering particles in the scattering layer 724 scatter light and widen or narrow the line profiles of their respective arrays in the same manner as the scattering particles within the integrated phosphor layer containing the scattering particles.

[0067] The scattering layer 724 may include a binder in which the third scattering particles are disposed. The binder may be the same binder as that used in the phosphor layer 720. Alternatively, the binder in the scattering layer 724 is different from that used in the phosphor layer 720.

[0068] Fig.10 An embodiment of the present invention is shown, which is arranged with Fig. 9 Similar, but the first array 702 has a phosphor layer 720 with first phosphor particles 752 without any scattering particles. In this case, the direct-emitting second array 704 has third scattering particles 786 designed to increase or decrease scattering (e.g., widen or narrow the line profile of light emitted from the second array 704) to match the line profile of the first array 702.

[0069] Fig.11The first array 702 includes an integrated phosphor layer 722 with first scattering particles 756, a second array 704 includes an integrated phosphor layer 722 with second scattering particles 766, and a third array 706 includes an integrated phosphor layer 722 with third scattering particles 776. The third scattering particles 776 can differ from the first scattering particles 756 in the same manner as the second scattering particles 766 in shape, size, density, composition, and / or other characteristics (e.g., Figure 8 and as described in the description of other figures above) and are different from or the same as the first scattering particles 756 and / or the second scattering particles 766.

[0070] Fig.12 The present invention includes: a first array 702 having a phosphor layer 720 without scattering particles and a scattering layer 724 with fourth scattering particles 796; and a second array 704 having a phosphor layer 722 without scattering particles and a scattering layer 724 with fifth scattering particles 796. The fourth scattering particles 796 and the fifth scattering particles 806 can be different from the first scattering particles 756 in the same manner as the second scattering particles 766 in terms of shape, size, density, composition and / or other characteristics (e.g., in Figure 8 and as described in the description of the other figures above) and are different from each other. Fig.12 The scattering layers 724 in the LEDs 710 are disposed above the phosphor layer 720 in their respective arrays. They may be in direct contact with the phosphor array or spaced apart. Even when they are in direct contact, they may be considered to be in separate layers, for example, in terms of mixing properties. Alternatively, the scattering layers 724 may be below the phosphor layer 720, so as to be between the phosphor layer 720 and the LEDs 710. In addition to these characteristics, Fig.12 The scattering layer 724 in the Fig. 9 The scattering layer 724 in the direct emission array is the same or similar.

[0071] The scattering particles in the scattering layer 724 scatter light and broaden or narrow the line profile of its corresponding array in the same manner as scattering particles within an integrated phosphor layer containing scattering particles. Because these scattering particles are placed in a separate scattering layer 724, their size is independent of the size segregation of the phosphor they are placed on top of because they are placed in a separate layer. They also do not need to be surface functionalized.

[0072] Fig.13A first array 702 is included, which has a spatially varying phosphor layer 723 that spatially varies in phosphor properties and a spatially varying scattering layer 726 that spatially varies in scattering particle properties. Phosphor and scattering particle properties include material, shape, size and / or size distribution, and / or density. For example, the properties of the phosphors and scattering particles disposed on individual pixels that emit the same color (but may not be adjacent to each other) can be the same for all of them. As a result, even if the spatially varying phosphor layer 723 includes three types of phosphor regions 752, 762, and 772 for three different types and / or colors of pixels, the spatially varying scattering layer 726 also has three types of scattering particle regions 796, 806, and 816 corresponding to the three types of pixels, respectively. In this way, the three types of scattering particle regions 796, 806, and 816 provide different levels of scattering to normalize the three types of pixels so that they have, for example, the same or substantially the same brightness line profile in the far field after they propagate through the optical element 715. The respective regions 796, 806 and 816 of scattering particles and the respective phosphor regions 752, 762 and 772 may be disposed only within the boundaries of an imaginary vertical line drawn from the sidewalls of their respective LEDs 710, although this is not required.

[0073] The present disclosure is illustrative, and not restrictive. Further modifications will be apparent to those skilled in the art in view of the present disclosure, and are intended to fall within the scope of the appended claims.

Claims

1. A light emitting device, comprising: Optical components; A first light emitting array configured to emit first light through the optical element into a far field, the first light comprising light of a first wavelength and light of a second wavelength and having a first brightness line profile with a first spatial width in the far field, the first light emitting array comprising: a first light emitting diode (LED) configured to emit light at the first wavelength, a first phosphor layer disposed in a light path of the first LED and comprising first phosphor particles configured to absorb at least some of the light at the first wavelength and emit light at the second wavelength; a second light emitting array disposed adjacent to the first light emitting array and configured to emit second light through the optical element into a far field, the second light comprising light of the first wavelength and light of a third wavelength, the second light emitting array comprising: a second LED configured to emit light at the third wavelength, a second phosphor layer arranged in a light path of the second LED, comprising: second phosphor particles configured to absorb at least some of the light at the third wavelength and emit light at a fourth wavelength, and Second scattering particles are arranged to scatter at least one of the light of a third wavelength emitted by the second LED and the light of a fourth wavelength emitted by the second phosphor particles, so that a second brightness line profile of the second light emitted by the second light-emitting array in the far field is widened or narrowed to have a second spatial width. 2 . The light emitting device according to claim 1 , wherein the first light is one of red, blue, and green, and the second light is another one of red, blue, and green different from the first light.

3. The light emitting device according to claim 1, wherein the light of the first wavelength is blue, the light of the second wavelength is one of yellow, green and red, and the light of the fourth wavelength is another one of yellow, green and red different from the light of the second wavelength. The light emitting device according to claim 1 , wherein the first space width is substantially as wide as the second space width.

5. The light-emitting device according to claim 1, wherein the first phosphor layer includes first scattering particles, and the first scattering particles are arranged to scatter at least one of the first wavelength of light emitted by the first LED and the second wavelength of light emitted by the second phosphor particles, so that the first brightness line profile in the far field is widened or narrowed to have the first spatial width. 6 . The light emitting device according to claim 5 , wherein the first brightness line profile is widened or narrowed to have the first spatial width, and the second brightness line profile is widened or narrowed identically to the first brightness line profile to have the second spatial width. The light emitting device according to claim 1 , wherein the optical element is a lens. 8 . The light emitting device according to claim 1 , wherein the second phosphor particles are uniformly distributed in the second phosphor layer, and the second scattering particles are uniformly distributed in the second phosphor layer. 9 . The light emitting device according to claim 1 , wherein the second scattering particles include or are aluminum oxide, titanium dioxide, or glass.

10. The light emitting device of claim 1, wherein the first phosphor layer does not include scattering particles of aluminum oxide, titanium dioxide, or glass. The light emitting device of claim 1 , wherein the first phosphor layer and the second phosphor layer are discrete layers spaced apart from each other without direct contact. 12 . The light emitting device of claim 1 , wherein the first phosphor layer and the second phosphor layer are integrated to form a continuous phosphor layer.

13. The light-emitting device according to claim 1 further includes a third light-emitting array, which is arranged adjacent to one of the first light-emitting array and the second light-emitting array and is configured to emit a third light including a fifth wavelength of light through the optical element into the far field, and the third light-emitting array includes a third LED configured to emit the fifth wavelength of light. The light emitting device according to claim 1 , wherein the first wavelength and the third wavelength are the same wavelength.

15. A light emitting device, comprising: Optical components; A first light emitting array configured to emit first light through the optical element into a far field, the first light comprising light of a first wavelength and light of a second wavelength and having a first brightness line profile with a first spatial width in the far field, the first light emitting array comprising: a first light emitting diode (LED) configured to emit light at the first wavelength, comprising a first phosphor layer of first phosphor particles configured to absorb at least some of the light at the first wavelength and to emit light at the second wavelength; a second light emitting array disposed adjacent to the first light emitting array and configured to emit a second light through the optical element into a far field, the second light comprising light of a third wavelength, the second light emitting array comprising: a second LED configured to emit light at the third wavelength, A second scattering layer including second scattering particles, wherein the second scattering particles are arranged to scatter at least one of the third wavelengths of light emitted by the second LED so as to widen or narrow a second brightness line profile of the second light emitted by the second light emitting array in the far field to have a second spatial width.

16. A light-emitting device according to claim 15, wherein the first phosphor layer has first scattering particles, the first scattering particles including first scattering particles arranged to scatter at least one of the first wavelength of light emitted by the first LED and the second wavelength of light emitted by the second phosphor particles, so that the first brightness line profile in the far field is widened or narrowed to have the first spatial width.

17. The light emitting device according to claim 15, further comprising a third light emitting array, the third light emitting array being disposed adjacent to one of the first light emitting array and the second light emitting array and configured to emit third light including light of the fourth wavelength and light of the fifth wavelength through the optical element into the far field, the third light emitting array comprising: a third LED configured to emit light at a fourth wavelength; a third phosphor layer arranged in a light path of the third LED, comprising: third phosphor particles configured to absorb at least some of the light at the fourth wavelength and emit light at a fifth wavelength, and Third scattering particles are arranged to scatter at least one of light of a fourth wavelength emitted by the third LED and light of a fifth wavelength emitted by the third phosphor particles, so that a third brightness line profile of the third light emitted by the second light-emitting array in the far field is widened or narrowed to have a third spatial width.

18. A light emitting device comprising: Optical components; A first light emitting array configured to emit first light through the optical element into a far field, the first light comprising light of a first wavelength and light of a second wavelength and having a first brightness line profile with a first spatial width in the far field, the first light emitting array comprising: a first light emitting diode (LED) configured to emit light at the first wavelength, comprising a first phosphor layer of first phosphor particles configured to absorb at least some of the light at the first wavelength and emit light at the second wavelength, a first scattering layer including first scattering particles, the first scattering particles being arranged to scatter at least one of light of a first wavelength emitted by the first LED and light of a second wavelength emitted by the first phosphor particles so as to widen or narrow a first brightness line profile of first light emitted by the first light emitting array in the far field to have a first spatial width; a second light emitting array arranged and configured to emit second light through the optical element into a far field, the second light comprising light of a third wavelength and light of a fourth wavelength, the second light emitting array comprising: a second LED configured to emit light at a third wavelength, a second phosphor layer including second phosphor particles configured to absorb at least some of the light of the third wavelength and emit light of a fourth wavelength, A second scattering layer includes second scattering particles, wherein the second scattering particles are arranged to scatter at least one of light of a third wavelength emitted by the second LED and light of a fourth wavelength emitted by the second phosphor particles, so that a second brightness line profile of second light emitted by the second light-emitting array in the far field is widened or narrowed to have a second spatial width.

19. The light emitting device according to claim 18, further comprising a third light emitting array, the third light emitting array being disposed adjacent to one of the first light emitting array and the second light emitting array and configured to emit a third light including light of a fifth wavelength through the optical element into the far field, the third light emitting array comprising: a third LED configured to emit light at a fifth wavelength; A third scattering layer includes third scattering particles, wherein the third scattering particles are arranged to scatter light of a fifth wavelength emitted by the third LED so that a third brightness line profile of second light emitted by the third light emitting array in the far field is widened or narrowed to have a third spatial width.

20. The light emitting device according to claim 19, wherein: The third light emitting array further includes a third phosphor layer including third phosphor particles configured to absorb at least some of the light of the fifth wavelength and emit light of a sixth wavelength, The third light emitted by the third light emitting array and passing through the optical element into the far field also includes light of a sixth wavelength, and The third scattering layer is arranged to scatter light of a sixth wavelength emitted by the third phosphor layer.

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