Semiconductor light emitting device including a superstrate having a patterned surface

Abstract

A semiconductor light emitting device comprises: a light emitting diode (LED) chip; a receptor luminescent medium on the LED chip; and a patterned cover plate on the receptor luminescent medium opposite the LED chip, the patterned cover plate comprising a patterned cover plate on the receptor luminescent medium opposite the LED chip, the patterned cover plate comprising a patterned surface, the patterned surface being configured to reduce the variation of the color point of light emitted by the semiconductor light emitting device with angles away from the optical axis of the LED chip.

Description

[0001] Related Applications

[0002] This application claims the benefit under 35 USC §119(e) of U.S. Provisional Application Serial No. 62 / 661,359, filed on April 23, 2018, entitled “SEMICONDUCTOR LIGHT EMITTING DEVICES INCLUDING SUPERSTRATES WITH PATTERNED SURFACES,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to light emitting devices, and more particularly, to semiconductor light emitting devices including a superstrate having a patterned surface. Background Art

[0004] Today, semiconductor light-emitting devices are widely used. Semiconductor light-emitting devices typically include one or more light-emitting diode chips ("LEDs" or "LED chips"). Each LED chip can include a series of semiconductor layers, which can be epitaxially grown on a substrate such as a sapphire, silicon, silicon carbide, gallium nitride, or gallium arsenide substrate. One or more semiconductor pn junctions are formed in these epitaxial layers. When a sufficient voltage is applied across the pn junction, electrons in the n-type semiconductor layer and holes in the p-type semiconductor layer flow toward the pn junction. As the electrons and holes flow toward each other, the electrons will "collide" with the corresponding holes and recombine, which will result in the emission of photons of light. The wavelength distribution of the light emitted by the LED chip typically depends on the semiconductor materials used and the structure of the thin epitaxial layers that constitute the "active region" of the device, which is where electron-hole recombination occurs.

[0005] LED chips are almost monochromatic light sources and appear to emit light having a single color. The spectral power distribution of the light emitted by the LED can be centered about a "peak" wavelength, which is the wavelength at which the spectral power distribution of the LED chip reaches its maximum value detected by a light detector. The width of the spectral power distribution of the LED chip is typically between about 10 nm and 30 nm, where the width can be measured at half the maximum illumination on each side of the emission peak (this width can be referred to as the full width at half maximum or "FWHM" width).

[0006] Visible light may include light having a variety of different wavelengths. The apparent color of visible light may be illustrated with reference to a two-dimensional chromaticity diagram, such as Figure 1 The 1931 CIE chromaticity diagram shown in , which provides a reference for defining color as a weighted sum of colors. Figure 1Colors on the CIE chromaticity diagram are defined by x (ccx) and y (ccy) coordinates (i.e., chromaticity coordinates) that fall within a generally U-shaped region, as shown in . Colors on or near the outside of the region are saturated colors composed of light having a single wavelength or a very small distribution of wavelengths, while colors on the inside of the region are unsaturated colors composed of a mixture of different wavelengths. Usually near the middle of the diagram, in Figure 1 White light, which may be a mixture of many different wavelengths, is found in the region labeled 10 in FIG. 1. As evidenced by the size of region 10, there are many different hues of light that may be considered "white." For example, some "white" light, such as light generated by high-power sodium vapor lighting devices, may appear to have a yellowish color, while other "white" light, such as light generated by certain fluorescent lighting devices, may appear to have a more bluish color.

[0007] The combination of light from the light sources emitting light of the first and second colors may appear to have a color different from either of the two constituent colors. The color of the combined light may depend on the wavelengths and relative intensities of the two light sources. For example, light emitted by a combination of a blue light source and a red light source may appear purple or magenta to an observer. Similarly, light emitted by a combination of a blue light source and a yellow light source may appear white to an observer. Figure 1 Each point on the graph of is called a "color point" of a light source that emits light of that color. Figure 1 As shown in , there is a color point locus called the "black body" locus 15, which corresponds to the location of the color point of light emitted by a black body radiator heated to various temperatures. The black body locus 15 is also called the "Planck" locus because the chromaticity coordinates (i.e., color points) along the black body locus obey the Planck equation: E(λ) = Aλ -5 / (e B / T -1), where E is the emission intensity, λ is the emission wavelength, T is the color temperature of the black body, and A and B are constants. Color points that lie on or near the black body locus 15 produce pleasing white light for human observers.

[0008] As a heated object becomes incandescent, it will first emit reddish light, then yellowish light, and finally bluish light as the temperature increases. This occurs because the wavelength associated with the peak radiation of a blackbody radiator becomes gradually shorter as the temperature increases, which is consistent with Wien's displacement law. Therefore, illuminants that produce light on or near the blackbody locus 15 can be described according to their correlated color temperature (CCT). As used herein, the term "white light" refers to light that is perceived as white, which is within the 7 MacAdam ellipse of the blackbody locus on the 1931 CIE chromaticity diagram and has a CCT ranging from 2000K to 10,000K. White light with a CCT of 4000K may appear to be yellowish in color, while white light with a CCT of 8000K or higher may appear to be bluish in color and may be referred to as "cold" white light. "Warm" white light can be used to describe white light with a CCT between about 2500K and 4500K, which is more reddish or more yellowish in color.

[0009] A semiconductor light emitting device that emits white light can be provided by surrounding an LED chip with one or more luminescent materials such as phosphors, which absorb some of the light emitted by the LED chip and responsively emit one or more other colors of light. This process is also referred to herein as "converting" some of the light emitted by the LED chip into (one or more) other colors of light. The combination of light emitted by the LED that is not converted by the luminescent material and light of (one or more) other colors emitted by the luminescent material can produce light that appears to an observer to be white or nearly white.

[0010] As an example, a white emitting LED package may be formed by coating a gallium nitride based blue LED (i.e., an LED emitting light having a peak wavelength in the blue range as defined herein) with a "yellow" phosphor (i.e., a phosphor emitting light having a peak wavelength in the yellow range), such as a cerium doped yttrium aluminum garnet phosphor having the chemical formula Y3Al5O 12:Ce, commonly referred to as YAG:Ce. The blue LED emits light having a peak wavelength of, for example, about 460nm. Some of the blue light emitted by the LED passes between and / or through the YAG:Ce phosphor particles without being converted, while other blue light emitted by the LED is absorbed by the YAG:Ce phosphor, becoming excited and emitting a broad-spectrum fluorescence having a peak wavelength of about 550nm. The broad-spectrum light emitted by the YAG:Ce phosphor can include a variety of different colors of light (e.g., green, yellow, orange, and even red light), and generally appears to be yellowish in color because the peak intensity of the emitted light is in the yellow range. The combination of blue light from the LED that is not converted by the YAG:Ce phosphor and light of other colors emitted by the YAG:Ce phosphor may appear white to an observer. This light is generally considered to be cool white because it primarily includes light in the lower half (shorter wavelength side) of the visible emission spectrum. In order to make the emitted white light appear "warmer" and / or exhibit better color rendering, phosphor particles emitting light with a peak wavelength in the red range, such as those based on Eu 2+ A phosphor of doped CaAlSiN3 is added to the coating applied to the blue LED.

[0011] Typically, a phosphor absorbs light having a first wavelength, and re-emits light having a second wavelength that is different (typically longer) than the first wavelength. For example, a "down-conversion" phosphor may absorb light having a shorter wavelength and re-emit light having a longer wavelength. It will be understood that the term "phosphor" is used broadly herein to include not only materials that are traditionally referred to as phosphorescent, but also other luminescent materials such as quantum dots that absorb light at one wavelength and re-emit light at a different wavelength in the visible spectrum, for example.

[0012] Typically, for example, the phosphor particles are mixed into a binder material such as an epoxy-based or silicone-based curable resin, which is then coated, sprayed or poured onto the LED or another surface of the luminaire. In this article, such a mixture is referred to as a "receptor luminescent medium". The receptor luminescent medium can include a layer in which one or more phosphors are mixed, a plurality of stacked layers, and / or a plurality of spaced-apart layers, each of which can include one or more of the same or different phosphors, and each of which can include the same or different phosphors. Summary of the invention

[0013] According to some embodiments of the present invention, a semiconductor light emitting device includes: a light emitting diode (LED) chip; an acceptor light emitting medium on the LED chip; and a patterned cover on the acceptor light emitting medium opposite to the LED chip, wherein the patterned cover includes a patterned surface configured to reduce the variation of a color point of light emitted by the semiconductor light emitting device with an angle away from an optical axis of the LED chip.

[0014] In some embodiments, the patterned surface comprises a plurality of optical elements.

[0015] In some embodiments, the plurality of optical elements are configured to reduce the amount of light emitted by the semiconductor light emitting device while reducing a variation in a color point of the light emitted by the semiconductor light emitting device with viewing angle.

[0016] In some embodiments, at least one of the plurality of optical elements comprises a convex protrusion.

[0017] In some embodiments, the convex protrusion comprises a non-linear sidewall.

[0018] In some embodiments, at least one of the plurality of optical elements comprises a concave recess.

[0019] In some embodiments, at least one of the plurality of optical elements has a circular cross-section.

[0020] In some embodiments, at least one of the plurality of optical elements has a polygonal cross-section.

[0021] In some embodiments, a plurality of optical elements are arranged in a grid on a patterned superstrate.

[0022] In some embodiments, a surface of the patterned superstrate opposite the patterned surface is a substantially planar surface.

[0023] In some embodiments, a plurality of optical elements are on a top surface of the patterned superstrate.

[0024] In some embodiments, a plurality of optical elements are on a bottom surface of the patterned superstrate.

[0025] In some embodiments, a height of at least one of the plurality of optical elements is between 1 and 3 micrometers (μm), and a width of at least one of the plurality of optical elements is between 2 and 4 μm.

[0026] In some embodiments, the pitch of the plurality of optical elements is between 0.5 and 10 μm.

[0027] In some embodiments, a pitch of the plurality of optical elements is between 0.5 and 10 times the width of a corresponding one of the plurality of optical elements.

[0028] In some embodiments, the patterned surface is a first patterned surface, the patterned cover plate includes a second patterned surface on an opposite side of the patterned cover plate from the first patterned surface, and the plurality of optical elements includes a first optical element on the first patterned surface and a second optical element on the second patterned surface.

[0029] In some embodiments, the patterned superstrate directly contacts the recipient light emitting medium.

[0030] In some embodiments, the semiconductor light emitting device further includes an air gap between the patterned superstrate and the recipient light emitting medium.

[0031] In some embodiments, the patterned superstrate includes a first patterned superstrate, and the semiconductor light emitting device further includes a second superstrate on the first patterned superstrate, the second superstrate having a major surface adjacent to the patterned surface of the first patterned superstrate.

[0032] In some embodiments, the first patterned superstrate includes a plurality of first optical elements, and the second superstrate includes a second patterned superstrate including a plurality of second optical elements.

[0033] In some embodiments, the first patterned superstrate includes a first index of refraction and the second superstrate includes a second index of refraction different from the first index of refraction.

[0034] In some embodiments, the semiconductor light emitting device further includes an adhesive layer between the recipient luminescent medium and the LED chip.

[0035] In some embodiments, the patterned cover plate is transparent.

[0036] In some embodiments, the patterned surface is configured to reduce the variation of both ccx and ccy coordinates of light emitted by the semiconductor light emitting device to within 0.01 for substantially all viewing angles within 40 degrees of an optical axis extending through the LED chip and perpendicular to the major surface of the LED chip.

[0037] According to some embodiments of the present invention, a semiconductor light emitting device includes: a light emitting diode (LED) chip and a chip cover directly mounted on the LED chip. The chip cover includes: a patterned cover plate including a plurality of optical elements; and a receptor luminescent medium on the patterned cover plate, wherein the receptor luminescent medium is between the LED chip and the patterned cover plate.

[0038] In some embodiments, at least one of the plurality of optical elements comprises a convex protrusion.

[0039] In some embodiments, the convex protrusion comprises a non-linear sidewall.

[0040] In some embodiments, at least one of the plurality of optical elements comprises a concave recess.

[0041] In some embodiments, at least one of the plurality of optical elements has a circular cross-section.

[0042] In some embodiments, at least one of the plurality of optical elements has a polygonal cross-section.

[0043] In some embodiments, a plurality of optical elements are arranged in a grid on a patterned superstrate.

[0044] In some embodiments, the patterned superstrate includes a patterned surface, and a surface of the patterned superstrate opposite the patterned surface is a substantially planar surface.

[0045] In some embodiments, a plurality of optical elements are on a top surface of the patterned superstrate.

[0046] In some embodiments, the plurality of optical elements are on a bottom surface of the patterned superstrate.

[0047] In some embodiments, the patterned superstrate directly contacts the recipient light emitting medium.

[0048] In some embodiments, the semiconductor light emitting device further includes an air gap between the patterned superstrate and the recipient light emitting medium.

[0049] In some embodiments, the patterned superstrate includes sapphire, silicon carbide, fused silica, and / or glass.

[0050] In some embodiments, the plurality of optical elements are configured to reduce the amount of light emitted by the semiconductor light emitting device while reducing a variation in a color point of the light emitted by the semiconductor light emitting device with viewing angle.

[0051] In some embodiments, a height of at least one of the plurality of optical elements is between 1 and 3 micrometers (μm), and a width of at least one of the plurality of optical elements is between 2 and 4 μm.

[0052] In some embodiments, the pitch of the plurality of optical elements is between 0.5 and 10 μm.

[0053] In some embodiments, a pitch of the plurality of optical elements is between 0.5 and 10 times the width of a corresponding one of the plurality of optical elements.

[0054] In some embodiments, the patterned superstrate includes a first patterned superstrate having a patterned surface, and the semiconductor light emitting device further includes a second superstrate on the first patterned superstrate, the second superstrate having a major surface adjacent to the patterned surface of the first patterned superstrate.

[0055] In some embodiments, wherein the first patterned superstrate comprises a plurality of first optical elements and the second superstrate comprises a second patterned superstrate comprising a plurality of second optical elements.

[0056] In some embodiments, the first patterned superstrate includes a first index of refraction and the second superstrate includes a second index of refraction different from the first index of refraction.

[0057] In some embodiments, the semiconductor light emitting device further includes an adhesive layer between the recipient luminescent medium and the LED chip.

[0058] In some embodiments, the patterned cover sheet is transparent.

[0059] In some embodiments, the patterned superstrate includes a first patterned surface and a second patterned surface, the second patterned surface being on an opposite side of the patterned superstrate from the first patterned surface, and the plurality of optical elements includes a first optical element on the first patterned surface and a second optical element on the second patterned surface.

[0060] In some embodiments, the patterned superstrate is configured to reduce the variation of both ccx and ccy coordinates of light emitted by the semiconductor light emitting device to within 0.01 for substantially all viewing angles within 40 degrees of an optical axis extending through the LED chip and perpendicular to a major surface of the LED chip.

[0061] According to some embodiments of the present invention, a semiconductor light emitting device includes: a light emitting diode (LED) chip; an acceptor light emitting medium on the LED chip; and a patterned cover on the acceptor light emitting medium opposite the LED chip, the patterned cover including a patterned surface configured to reduce the variation of both ccx and ccy color coordinates of light emitted by the semiconductor light emitting device to within 0.01 for substantially all viewing angles within 40 degrees of an optical axis extending through the LED chip and perpendicular to a major surface of the LED chip.

[0062] In some embodiments, the recipient luminescent medium includes a phosphor material and a binder material, and the difference between a first refractive index of the binder material and a second refractive index of the patterned superstrate is at least 0.3.

[0063] In some embodiments, the patterned surface includes a plurality of optical elements.

[0064] In some embodiments, the plurality of optical elements redirect a portion of light emitted from the LED chip that is at least 45° from the optical axis to within 30° of the optical axis extending through the LED chip and perpendicular to a major surface of the LED chip.

[0065] In some embodiments, the plurality of optical elements redirect a portion of light emitted from the LED chip that is at least 10° from the optical axis to be more than 30° from the optical axis extending through the LED chip and perpendicular to a major surface of the LED chip.

[0066] In some embodiments, at least one of the plurality of optical elements comprises a convex protrusion.

[0067] In some embodiments, the convex protrusion comprises a non-linear sidewall.

[0068] In some embodiments, at least one of the plurality of optical elements comprises a concave recess.

[0069] In some embodiments, at least one of the plurality of optical elements has a circular cross-section.

[0070] In some embodiments, at least one of the plurality of optical elements has a polygonal cross-section.

[0071] In some embodiments, a surface of the patterned superstrate opposite the patterned surface is a substantially planar surface.

[0072] In some embodiments, a plurality of optical elements are on a top surface of the patterned superstrate.

[0073] In some embodiments, a plurality of optical elements are on a bottom surface of the patterned superstrate.

[0074] In some embodiments, the plurality of optical elements are configured to reduce the amount of light emitted by the semiconductor light emitting device while reducing a variation in a color point of the light emitted by the semiconductor light emitting device with viewing angle.

[0075] In some embodiments, a height of at least one of the plurality of optical elements is between 1 and 3 microns, and a width of at least one of the plurality of optical elements is between 2 and 4 μm.

[0076] In some embodiments, the pitch of the plurality of optical elements is between 0.5 and 10 microns.

[0077] In some embodiments, a pitch of the plurality of optical elements is between 0.5 and 10 times the width of a corresponding one of the plurality of optical elements.

[0078] In some embodiments, a plurality of optical elements are arranged in a grid on a patterned superstrate.

[0079] In some embodiments, the grid is hexagonal.

[0080] In some embodiments, the plurality of optical elements are arranged in an irregular pattern on the patterned cover plate.

[0081] In some embodiments, the patterned surface is a first patterned surface, the patterned cover plate includes a second patterned surface on an opposite side of the patterned cover plate from the first patterned surface, and the plurality of optical elements includes a first optical element on the first patterned surface and a second optical element on the second patterned surface.

[0082] In some embodiments, the patterned surface is configured to reduce the variation of both ccx and ccy coordinates of light emitted by the semiconductor light emitting device to within 0.005 for substantially all viewing angles within 40 degrees of an optical axis extending through the LED chip and perpendicular to the major surface of the LED chip.

[0083] In some embodiments, the patterned cover sheet is transparent.

[0084] In some embodiments, the patterned superstrate directly contacts the recipient light emitting medium.

[0085] In some embodiments, the semiconductor light emitting device further includes an air gap between the patterned superstrate and the recipient light emitting medium.

[0086] In some embodiments, the patterned superstrate includes sapphire, silicon carbide, fused silica, and / or glass.

[0087] In some embodiments, the patterned superstrate includes a first patterned superstrate, and the semiconductor light emitting device further includes a second superstrate on the first patterned superstrate, the second superstrate having a major surface adjacent to the patterned surface of the first patterned superstrate.

[0088] In some embodiments, the first patterned superstrate includes a plurality of first optical elements, and the second superstrate includes a second patterned superstrate including a plurality of second optical elements.

[0089] In some embodiments, the first patterned superstrate includes a first index of refraction and the second superstrate includes a second index of refraction different from the first index of refraction. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] The patent or application file contains at least one drawing printed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0091] Figure 1 The 1931 CIE chromaticity diagram for defining colors by chromaticity coordinates is illustrated.

[0092] Figure 2 is a schematic cross-sectional view of a conventional semiconductor light emitting device including a chip cover.

[0093] Figure 3Ais a schematic cross-sectional view of a conventional semiconductor light emitting device, illustrating various viewing angles of light emitted from the device.

[0094] Figure 3B and Figure 3C is a graph illustrating the relationship between changes in the perceived color of light emitted from a conventional semiconductor light emitting device and the viewing angle of the emitted light.

[0095] Figure 4 is a schematic cross-sectional view of a semiconductor light emitting device according to an embodiment of the present invention.

[0096] Figure 5A and Figure 5B is a simulation diagram illustrating the operation of the semiconductor light emitting device according to the embodiment of the present invention compared with a conventional device. Figure 5C and Figure 5D yes Figure 5B The enlarged part.

[0097] Fig. 6A , Figure 6B , Figure 6C , Fig. 7A , Figure 7B , Figure 7C , Fig. 8A , Figure 8B and Figure 8C is a schematic cross-sectional view of an example configuration of an optical element included in a semiconductor light emitting device according to some embodiments of the present invention.

[0098] Fig. 9A is a schematic cross-sectional view of a semiconductor light emitting device according to an embodiment of the present invention, wherein an optical element is on a top surface of a patterned superstrate.

[0099] Fig. 9B It is a graphic Fig. 9A Schematic diagram of the operation of the semiconductor light emitting device.

[0100] Fig. 10A , Fig. 10B and Fig. 10C The diagram shows the Fig. 6A , Fig. 7A and Fig. 8A A semiconductor light emitting device similar to the semiconductor light emitting device of the present invention, wherein the optical element is recessed into the surface of the patterned cover plate.

[0101] Fig.11A and Fig. 11B is a schematic cross-sectional view of an example semiconductor light emitting device including a recessed optical element in a patterned superstrate.

[0102] Fig. 12A and Fig. 12Bis a schematic cross-sectional view of an example semiconductor light emitting device in which an optical element is provided as a protrusion between two superstrate plates.

[0103] Fig. 12C and Fig.12D is a schematic cross-sectional view of an example semiconductor light emitting device in which an optical element is disposed as a recess between two superstrate plates.

[0104] Fig.12E and Fig.12F is a schematic cross-sectional view of an example semiconductor light emitting device including more than one patterned superstrate.

[0105] Figure 12G and Fig.12H is a schematic cross-sectional view of an example semiconductor light emitting device having a patterned superstrate with optical elements on both surfaces.

[0106] Fig.13 is a schematic cross-sectional view of a semiconductor light emitting device in which a patterned superstrate includes an internal optical element.

[0107] Fig.14 is a schematic cross-sectional view of a semiconductor light emitting device further comprising an air gap between the patterned superstrate and the recipient light emitting medium.

[0108] Fig.15 is included in a molded lighting device including a lens Figure 4 Schematic cross-sectional view of a semiconductor light emitting device.

[0109] Fig.16 is a schematic cross-sectional view of a patterned superstrate used in a semiconductor light emitting device including a plurality of LED chips.

[0110] Fig.17A and Fig. 17B is a graph illustrating the color variation with angle of a conventional device and a semiconductor light emitting device according to an embodiment of the present invention.

[0111] Fig. 17C is a graph illustrating the difference in color-angle performance of semiconductor light emitting devices with different types of patterned superstrate according to an embodiment of the present invention.

[0112] Fig.18A and Fig.18B is a graph illustrating the sharpness degradation that may be encountered using a conventional diffuser as compared to an example semiconductor light emitting device according to an embodiment of the present invention.

[0113] Fig.19A and Fig.19Bare graphs illustrating additional performance comparisons between conventional devices and example semiconductor light emitting devices according to embodiments of the present invention.

[0114] Fig. 20A and Fig. 20B is a graph showing the performance of a conventional semiconductor light emitting device.

[0115] Fig.21A and Fig. 21B is a graph illustrating the performance of an apparatus according to some embodiments described herein.

[0116] Fig.22A and Fig. 22B Included are graphs showing the variation of color with angle (CoA) in a semiconductor light emitting device including an optical element having a circular base and a semiconductor light emitting device including an optical element having a hexagonal base.

[0117] It should be noted that these figures are intended to illustrate the general characteristics of the methods, structures and / or materials utilized in certain example embodiments and to supplement the written description provided below. However, these figures are not drawn to scale and may not accurately reflect the structure or performance characteristics of any given embodiment and should not be interpreted as defining or limiting the range of values ​​or properties covered by the example embodiments described herein. For example, the relative thickness and position of layers, regions and / or structural elements may be reduced or exaggerated for clarity. The use of similar or identical reference numerals in the various figures is intended to indicate the presence of similar or identical elements or features. DETAILED DESCRIPTION

[0118] According to embodiments of the present invention, the uniformity of the color of light emitted by a semiconductor light emitting device over a range of viewing angles may be improved by adding a patterned overlay placed on a receptor luminescent medium of the semiconductor light emitting device opposite to the LED chip(s). The addition of the patterned overlay may alter the characteristics of the light emitted by the semiconductor light emitting device, thereby providing a more uniform color for the emitted light when viewed from different angles.

[0119] Conventional semiconductor light emitting devices utilizing LED chips with acceptor luminescent media may emit light that exhibits a change in the color of the emitted light as the viewing angle of the emitted light changes. For example, the color of light emitted from the semiconductor light emitting device may be a first color when the semiconductor light emitting device is viewed directly (e.g., straight-on) from the semiconductor light emitting device, but the color may be a second color as the viewing angle increases relative to straight-on. In other words, the perceived color of light emitted from the semiconductor light emitting device may be different when viewed from an oblique angle than when viewed from directly in front. The change in the color of light emitted by a semiconductor light emitting device at various viewing angles is known as the color variation over angle (CoA) of the device.

[0120] According to embodiments described herein, the CoA performance of a semiconductor light emitting device can be improved by including a patterned cover having a plurality of optical elements formed therein in the semiconductor light emitting device. The patterned cover can be positioned to receive light emitted from a recipient light emitting medium, which includes both light emitted by a phosphor in the recipient light emitting medium and unconverted light from an LED chip. As discussed herein, the use of the patterned cover can introduce additional refraction and / or reflection to the emitted light so as to improve the CoA variation of the emitted light over a wide viewing angle range.

[0121] According to some embodiments of the present invention, a semiconductor light emitting device is provided, which includes an LED chip, a receptor luminescent medium on the LED chip, and a patterned superstrate on the receptor luminescent medium opposite the LED chip. The patterned superstrate can be a patterned surface that reduces the variation of the color point of light emitted by the semiconductor light emitting device with the angle of deviation from a line perpendicular to the emitting surface of the LED chip.

[0122] According to a further embodiment of the present invention, a semiconductor light emitting device is provided, which includes an LED chip and a chip cover directly mounted on the LED chip. The chip cover may include a patterned cover plate and a receptor luminescent medium on the patterned cover plate, the patterned cover plate including a plurality of optical elements. The receptor luminescent medium may be positioned between the LED chip and the patterned cover plate.

[0123] According to an additional embodiment of the present invention, a semiconductor light emitting device is provided, the semiconductor light emitting device comprising an LED chip, a receptor luminescent medium on the LED chip, and a patterned superstrate on the receptor luminescent medium opposite the LED chip. The patterned superstrate comprises a patterned surface configured to reduce the variation of both ccx and ccy color coordinates of the emitted light to within 0.01 for substantially all viewing angles within 40 degrees of an axis extending perpendicular to a major surface of the LED chip.

[0124] Exemplary embodiments of the present invention will now be described in more detail with reference to the accompanying drawings.

[0125] Figure 2 2 is a schematic cross-sectional view of a conventional semiconductor light emitting device 200 including a chip cover 220. Figure 2As shown in , the chip cover 220 includes a superstrate 130 on which a receptor luminescent medium 110 is disposed. The chip cover 220 can substantially cover the LED chip 100 and can be positioned so that the receptor luminescent medium 110 is between the LED chip 100 and the superstrate 130. The LED chip 100 can, for example, be mounted on a support substrate 160 such as a ceramic substrate. The support substrate 160 can have a reflective upper surface so that light incident on the support substrate 160 is redirected back through the LED chip 100. The superstrate 130 can protect the surface of the receptor luminescent medium 110. For example, superstrate is discussed in U.S. Patent Application No. 15 / 657,027 to Andrews et al., entitled "Light Emitting Diodes, Components and Related Methods." The receptor luminescent medium 110 is typically sprayed and / or otherwise coated on the surface of the superstrate 130. For example, the acceptor luminescent medium is discussed in U.S. Patent Application No. 14 / 053,404 to Heikman et al., entitled “Chip with Integrated Phosphor.” The chip cover 220 can then be attached to the LED chip 100 using a transparent adhesive layer 105 to provide a semiconductor light emitting device 200. The term “superstrate” is used herein to refer to a layer placed on the LED chip, with the acceptor luminescent medium between the superstrate and the LED chip. It will be understood that the superstrate can be on either side of the LED chip. For example, in a flip chip configuration, the superstrate can be below the LED chip. The term “superstrate” is used herein in part to avoid confusion with other substrates that may be part of a semiconductor light emitting device, such as a substrate of an LED chip. The term “superstrate” is not intended to limit the orientation, position, and / or composition of the structure it describes.

[0126] Figure 3A yes Figure 2 Schematic cross-sectional view of a semiconductor light emitting device 200, which illustrates various viewing angles θ of light emitted from the device 200. Figure 3AAs shown in , the LED chip 100 can have an emission surface 100s through which light is emitted. The emission surface 100s can be a major surface of the LED chip 100, through which most of the light emitted by the LED chip 100 enters the acceptor luminescent medium 110. The emission surface 100s can be, for example, the top surface or the bottom surface of the LED chip 100. The light emitted by the LED chip 100 enters the acceptor luminescent medium 110. The acceptor luminescent medium 110 can convert some of the light emitted from the LED chip 100 into one or more different colors of light, while other light emitted by the LED chip 100 can pass through the acceptor luminescent medium without conversion. Therefore, the emitted light 120 output from the semiconductor light emitting device 200 includes both unconverted light generated by the LED chip 100 and light emitted by the acceptor luminescent medium 110.

[0127] like Figure 3A As shown in , the emitted light 120 may include light emitted at multiple angles. For example, the emitted light 120 may include a first light component 120a that is emitted at a relatively small angle θ1 relative to an optical axis N (e.g., the optical axis) that is perpendicular to the emission surface 100s of the LED chip 100. In this document, the optical axis N may also be referred to as the "surface normal" of the semiconductor light emitting device. Although the optical axis N may be described relative to the emission surface 100s of the LED chip 100, it will be understood that in some embodiments, the emission surface 100s may include a nonlinear and / or variable surface. In addition, in some embodiments, a majority of the light may be emitted through other surfaces such as a perpendicular LED surface adjacent to the surface 100s. Generally, the optical axis N refers to a direction corresponding to the peak emission luminous intensity of the device. An observer observing the semiconductor light emitting device 200 may observe the semiconductor light emitting device 200 from a position primarily facing the semiconductor light emitting device 200 (e.g., Figure 3A The first emitted light component 120a is sensed at position A) in the image.

[0128] In addition, the emitted light 120 may include a second emitted light component 120b emitted along a line that forms an angle θ2 with the optical axis N perpendicular to the emission surface 100s of the LED chip 100. An observer observing the semiconductor light emitting device 200 may observe the semiconductor light emitting device 200 from a position that is mainly oriented at a relatively large angle relative to the emission surface 100s of the LED chip 100 (e.g., Figure 3A The second light component 120b is sensed at position B) in the image.

[0129] As the viewing angle θ increases, the color of the emitted light 120 may also change. Figure 3B and Figure 3C 2 is a graph illustrating the relationship between the change in color of light emitted from a conventional semiconductor light emitting device 200 and the viewing angle θ of the emitted light 120. Figure 3B , the x-axis illustrates the viewing angle θ of light relative to the emission surface 100s of the LED chip 100. A viewing angle θ of 0 degrees indicates a viewing angle oriented along the optical axis N. Increasing (and decreasing) angles of the viewing angle θ indicate an angle along the optical axis N offset from the emission surface 100s perpendicular to the LED chip 100 (e.g., such as Figure 3A Points A and B in the image are oriented in perspective.

[0130] exist Figure 3B , the y-axis illustrates the change (dccx) of the ccx component of the emitted light 120 of the LED chip 100 with viewing angle θ as specified in the 1931 CIE chromaticity diagram. The change is relative to the color perceived along the optical axis N of the semiconductor light emitting device 200 (e.g., viewing angle θ of 0 degrees). For example, referring to Figure 1 , a change in the ccx component of the emitted light 120 may represent a shift in the color point of the emitted light 120 in the x-direction in the 1931 CIE chromaticity diagram. Figure 3C A similar change (dccy) of the ccy component of the color of the emitted light 120 with viewing angle θ (relative to the color perceived at a viewing angle θ of 0 degrees) is illustrated. Figure 3B and Figure 3C As shown in FIG. 1 , as the viewing angle θ increases relative to the optical axis N, the color of the emitted light 120 may change in the ccx and ccy directions. As a result of these changes, the color point of the light may change as the viewing angle θ changes relative to the semiconductor light emitting device 200, which may result in a change in the color point of the light from a first angle (e.g., at Figure 3A and light viewed from a second angle (e.g., at Figure 3A The perceptible color difference between the light viewed at position B).

[0131] The change in color may be due in part to the different paths taken by different components of the emitted light 120 as it passes through the recipient luminescent medium 110. Referring again to Figure 3A, a first emitted light component 120a that passes through the recipient luminescent medium 110 along a line that makes a relatively small angle θ1 with the optical axis N can take a relatively straight path through the recipient luminescent medium 110. In contrast, a second emitted light component 120b that passes through the recipient luminescent medium 110 at a relatively large angle θ2 with the optical axis N can traverse a greater distance through the recipient luminescent medium 110 than the first emitted light component 120a. As a result, the luminescent material of the recipient luminescent medium 110 can convert a greater proportion of the second emitted light component 120b than the first emitted light component 120a. Thus, light emitted at a larger angle with the optical axis N can include more "converted light" (i.e., light emitted by the luminescent material in the recipient luminescent medium 110) and less "through light" (i.e., light emitted by the LED chip 100 that passes through the recipient luminescent medium without undergoing wavelength conversion) than light emitted at a smaller angle with the optical axis N.

[0132] Conventional semiconductor light emitting devices have attempted to address this CoA variation by providing a diffuser layer (e.g., a layer including particles of TiO2, fused silica, etc.) on the recipient luminescent medium 110. However, such a diffuser layer may result in a reduction in the sharpness and / or contrast of the light emitted from the device compared to a conventional semiconductor light emitting device without such a layer, which may be of significant concern in some applications and may also increase the cost of the device. In addition, the diffuser layer may scatter a significant portion of the light back toward the LED chip 100 to where it may be absorbed, thereby reducing the overall efficiency of the LED chip 100 relative to the case where the scatterer is not present. Therefore, it is generally desirable to utilize optical effects such as refraction and total internal reflection (TIR) ​​to adequately mix the light while minimizing the amount of light directed back toward potentially absorbing surfaces.

[0133] Figure 4 is a schematic cross-sectional view of a semiconductor light emitting device 400 according to an embodiment of the present invention. Figure 2 As in the conventional device, Figure 4 The semiconductor light emitting device 400 includes an LED chip 100 on a support substrate 160. However, Figure 4 The semiconductor light emitting device 400 includes an improved chip cover 420. The improved chip cover 420 includes an acceptor light emitting medium 410 and a patterned superstrate 430. The patterned superstrate 430 may include a plurality of structures configured to redirect some of the light incident on the patterned superstrate 430 from the acceptor light emitting medium 410 in a favorable manner. In some embodiments, the structures may be on one or more surfaces of the patterned superstrate 430. In other embodiments, the structures may be within an interior region of the patterned superstrate 430.

[0134] The structure included in the patterned cover 430 may be referred to herein as an optical element 450. The optical element 450 is a feature formed in the patterned cover 430 that can be distinguished from random variations that may occur naturally and / or as an unintentional product of a manufacturing operation. In some embodiments, the optical element 450 may be arranged in a grid or other repeating configuration. In some embodiments, the optical element 450 may be a protrusion (e.g., extending from a convex shape of the patterned cover 430) and / or a depression (e.g., a concave feature in the patterned cover 430) in the surface of the patterned cover 430. In some embodiments, the optical element 450 may be a structural change in the surface of the patterned cover 430 that is intentionally placed to facilitate optical reflection. In some embodiments, the optical element 450 may be on multiple portions of the surface of the patterned cover 430, including on the edge and center of the surface of the patterned cover 430. In some embodiments, the optical element 450 may have a uniform shape and spacing across the patterned cover 430, while in other embodiments, the spacing or shape may vary across the patterned cover 430 according to the design.

[0135] Despite Figure 4 4 is shown as having a triangular cross-section, but the shape of the optical element 450 can vary in size and configuration, as further described herein, and Figure 4 The shape of the optical element 450 in FIG. 4 is for illustration only. The optical element 450 may be configured to further reflect the emission light 480 (which may include both direct light and converted light) emitted from the recipient light emitting medium in order to improve the CoA variation of the semiconductor light emitting device 400 .

[0136] like Figure 4 As shown in FIG. 4 , the acceptor luminescent medium 410 can be positioned between the optical element 450 and the LED chip 100 of the patterned superstrate 430. In some embodiments, the thickness of the acceptor luminescent medium 410 can be between 10 micrometers (μm) and 100 μm. In some embodiments, the patterned superstrate 430 can have a thickness between 125 μm and 165 μm.

[0137] In some embodiments, the patterned cover plate 430 may be composed of, for example, sapphire, silicon carbide, organosilicon, and / or glass (e.g., borosilicate and / or fused quartz). The patterned cover plate 430 may be formed by a bulk substrate that is patterned and then divided. In some embodiments, the bulk substrate may be patterned by an etching process (e.g., wet etching or dry etching). In some embodiments, the patterning of the bulk substrate may be performed by changing the surface in other ways, such as by a laser or saw. In some embodiments, the bulk substrate may be thinned before or after the patterning process is performed. The acceptor luminescent medium 410 may then be placed on the bulk substrate by, for example, spraying and / or otherwise coating the bulk substrate with the acceptor luminescent medium 410. The acceptor luminescent medium 410 is typically applied to the bulk substrate and then divided, for example, with a laser or mechanical saw, to form a separate chip cover 420 including the acceptor luminescent medium 410 and the patterned cover plate 430, but embodiments of the present invention are not limited thereto. The chip cover 420 may be attached to the LED chip 100 using, for example, a transparent adhesive layer 105. In some embodiments, the transparent adhesive layer 105 can be about 5 μm thick. A separate chip cap 420 can be placed on the LED chip 100 using, for example, a pick-and-place manufacturing process.

[0138] Although the patterned cover plate 430 is illustrated as part of the chip cover 420, embodiments of the present invention are not limited thereto. It will be understood that the semiconductor light emitting device 400 can be formed using the patterned cover plate 430 and the acceptor luminescent medium 410 without forming an intermediate improved chip cover 420. For example, in some embodiments, the acceptor luminescent medium 410 can be placed on the LED chip 100, for example, by spraying, pouring or coating, and the patterned cover plate 430 can be placed on the acceptor luminescent medium 410, such as by a pick-and-place operation. In other words, the acceptor luminescent medium 410 and the patterned cover plate 430 can be placed separately on the LED chip 100 without first forming a separate chip cover 420. In such an embodiment, the transparent adhesive layer 105 may not exist, but the embodiments described herein are not limited thereto. For example, if the LED chip 100 is configured as a flip-chip configuration, the transparent adhesive layer 105 may not exist.

[0139] Figure 4 Also included is an opaque filling region 470. The opaque filling region 470 may include a highly reflective surrounding material that may suppress side light emission from the semiconductor light emitting device 400 and favor top light emission, which is preferred. In some embodiments, the opaque filling region 470 may be composed of an organic silicon material and / or scattering particles. Figure 4The opaque fill region 470 shown in FIG. 4 may be included in each of the embodiments described herein. However, for the sake of brevity, the opaque fill region 470 may be omitted from the various illustrations of the semiconductor light emitting device included herein.

[0140] Figure 4 The structure of the semiconductor light emitting device 400 shown in the figure is intended to be representative, but embodiments of the present invention are not limited thereto. For example, additional layers such as adhesive layers, diffusion layers (e.g., adhesives with scattering particles), reflective and / or wavelength conversion layers may be present between the LED chip 100 and the patterned cover plate 430 and / or on the patterned cover plate 430.

[0141] Figure 5A and Figure 5B is a simulation diagram illustrating the operation of the semiconductor light emitting device according to the embodiment of the present invention compared with a conventional semiconductor light emitting device. Figure 5C and Figure 5D yes Figure 5B A magnified portion of the reference Figure 5A and Figure 5B , the simulation includes blue and yellow areas / lines. The blue area / line (an example of which is in Figure 5A 540 in the figure) represents light emitted at a small angle to the axis perpendicular to the light emitting surface of the underlying LED (e.g., Figure 3A The first component of the emitted light 120a), while the yellow area / line (an example of which is shown in Figure 5A 550) indicates light emitted at a relatively large angle to an axis perpendicular to the light emitting surface of the underlying LED (e.g., Figure 3A The second component of the emitted light 120b). Figure 5A and Figure 5B The light emitted from the individual emission points of the LED is schematically illustrated. In other words, Figure 5A and Figure 5B This does not necessarily represent all of the light emitted across the entire surface of the underlying LED (not shown), but rather is focused at a particular emission point 510. It will be understood that an LED has multiple emission points across the surface of the LED, emission point 510 being only one of them. Figure 5A and Figure 5B The phenomenon schematically illustrated in can be repeated across multiple points on the surface of the LED.

[0142] Figure 5A Light emission from a conventional semiconductor light emitting device is illustrated. Figure 5A The lower part of the diagram shows Figure 5A An exploded view of the upper portion "A". Figure 5AAs shown in , light emitted from emission point 510 at an angle close to perpendicular to the optical axis of the light emitting surface of the LED (e.g., light designated by blue region / line 540) is primarily directed outward along a central viewing angle (e.g., from about -45° to about 45°) with respect to the optical axis of the semiconductor light emitting device. Figure 5A As further illustrated in FIG. 5 , light emitted at a larger angle from the emission point 510 that is perpendicular to the axis of the light emitting surface of the LED (e.g., light designated using yellow region / line 550) is reflected at the interface between the recipient luminescent medium 110 and the conventional cover plate 130. This higher angle light is concentrated within a wider viewing angle (e.g., from a first portion between about -45° and -90° to a second portion between about 45° and 90°) from the optical axis of the semiconductor light emitting device. Figure 5A As can be seen, while there is internal reflection of emitted light within conventional cover sheet 130, the reflection is primarily of higher angle light (e.g., light designated by yellow area / line 550). Figure 5A In the lower portion of FIG. 1 , a slight bending and / or refraction of light rays is evident at the boundary between the luminescent medium 110 and the conventional cover plate 130. This refraction is due to the difference in refractive index between the two layers. Figure 5A In the case shown in FIG. 1 , the light emitting layer 110 has a lower refractive index (eg, 1.41) relative to the refractive index of a conventional superstrate (eg, 1.8).

[0143] Figure 5B Light emission from a semiconductor light emitting device according to some embodiments of the present invention is illustrated. Figure 5B The lower part of the diagram shows Figure 5B Exploded view of the upper part "B". Figure 5B As shown in , light emitted from emission point 510 at a small angle to an axis perpendicular to the light emitting surface of the LED (e.g., light designated by blue region / line 540) is directed outward along multiple viewing angles (e.g., from about -70° to about 70°) from the optical axis of the semiconductor light emitting device. Light emitted from emission point 510 at a larger angle to an axis perpendicular to the light emitting surface of the LED (e.g., light designated using yellow region / line 550) is also distributed across a wider viewing angle (e.g., from about -90° to about 90°) from the optical axis of the semiconductor light emitting device. Figure 5B As shown in FIG. 4 , for higher angle light (e.g., light designated using yellow regions / lines 550), there is internal reflection of the emitted light within the patterned cover plate 430. By mixing the angular distributions of normal and higher angle light, this combination of effects, i.e., refractive bending of normal angle light (e.g., light designated using blue regions / lines 540) toward higher angles and internal reflection of higher angle light (e.g., light designated using yellow regions / lines 550) toward normal, overcomes the non-uniformity of conventional CoA. In other words, compared to the conventional case (e.g., Figure 5A), internal reflection of light within the patterned cover plate 430 allows the distribution of light exiting the patterned cover plate 430 to be more consistent across a wider range of viewing angles.

[0144] The increased reflection within the patterned cover plate 430 is at least partially due to the optical element 450. The optical element 450 introduces an additional surface with an interface with the receptor luminescent medium 410, resulting in an increased refraction of light entering the patterned cover plate 430. It should be noted that this effect is not simply random scattering (e.g., isotropic scattering) of light that may be performed by other materials (such as diffusers). Rather, the interface between the patterned cover plate 430 and the receptor luminescent medium 410 presents a non-random distribution of interfaces with materials having different refractive indices. This increased surface area of ​​refractive index differences provides more opportunities for refraction of light that passes through the receptor luminescent medium 410 into the patterned cover plate 430 than is conventionally the case. This additional refracted light can then be reflected within the patterned cover plate 430 (e.g., via total internal reflection), resulting in an increased distribution of emitted light.

[0145] Thus, variables that may improve and / or affect the CoA variation of the device include the material used for the patterned superstrate 430 and the configuration of the optical element 450. For example, the material of the patterned superstrate 430 may contribute to the difference in refractive index between the patterned superstrate 430 and the recipient light emitting medium 410. The greater the difference between the refractive index of the patterned superstrate 430 and the refractive index of the recipient light emitting medium 410, the greater the amount of refraction, which may increase the amount of light that may be redirected in a manner that may improve the CoA performance of the semiconductor light emitting device. Although the described embodiments primarily include the case where the refractive index of the light emitting receptor medium 410 is lower than the refractive index of the patterned superstrate 430, it should be understood that in some embodiments, the difference may be reversed such that the light emitting receptor medium 410 has a higher refractive index than the patterned superstrate 430. In some embodiments, there may be intermediate layers or coatings having further different refractive indices or even a refractive index gradient.

[0146] In some embodiments, refraction can result in total internal reflection of a portion of the light. In some embodiments, reflection can be increased for light emitted at a relatively large angle to an axis perpendicular to the light emitting surface of the underlying LED. For example, with LEDs such as Figure 4Light that contacts an optical element 450, such as the optical element shown in FIG. 4 , can be altered twice. First, due to the difference between the refractive index of the patterned cover plate 430 and the refractive index of the recipient light emitting medium 410, the light can hit the first surface of the optical element 450 and be refracted. Second, the light can continue to travel through the optical element 450 and be altered again when it hits the opposite side (e.g., the opposite sidewall) of the optical element 450. The opposite side of the optical element 450 can reflect the light back into the patterned cover plate 430, and the light can be further reflected by other features of the semiconductor light emitting device before finally exiting the device through the patterned cover plate 430. The end result can be that light with a more uniform color point is emitted from the device across a wide range of viewing angles. By adjusting the configuration of the optical element 450 and the materials used in the patterned cover plate 430, the refractive index difference can be adjusted to enhance the distribution of light within the patterned cover plate 430. In some embodiments, the difference between the refractive index of the patterned cover plate 430 and the refractive index of the recipient light emitting medium 410 can be at least about 0.3, but the present disclosure is not limited thereto. In some embodiments, the difference between the refractive index of patterned superstrate 430 and the refractive index of recipient luminescent medium 410 may be between 0.1 and 2. In some embodiments, the difference between the refractive index of patterned superstrate 430 and the refractive index of recipient luminescent medium 410 may be between 0.01 and 0.5.

[0147] In addition to the material of the patterned cover plate 430, the placement and configuration of the optical element 450 can also play a role in the type of light that leaves the semiconductor light emitting device at different viewing angles. For example, the shape of the optical element 450 can affect the surface provided to the light emitted by the receptor light emitting medium 410. As will be further described herein, the shape of the optical element 450 can be selected to adjust the distribution of the light emitted by the semiconductor light emitting device. In addition, the arrangement (e.g., pitch) of the optical element 450 can also contribute to the change in the surface provided to the light emitted by the receptor light emitting medium 410. Therefore, the pitch of the optical element 450 can also be selected to adjust the distribution of the light emitted by the semiconductor light emitting device.

[0148] Figure 5C and Figure 5D yes Figure 5B The enlarged part. Figure 5C Various simulations are shown of the paths that higher angle light (eg, light designated as "yellow" in graph 550) might travel when encountering optical element 450. As shown in FIG. Figure 5D A similar simulation is shown for the path of light at a lower angle (e.g., light designated as "blue" in plot 540). Figure 5C and Figure 5D , the optical axis N of the semiconductor light emitting device is illustrated for orientation purposes. Figure 5C, higher angle light can contact optical element 450 as it leaves recipient luminescent medium 410. Due to the difference in refractive index between the materials of recipient luminescent medium 410 and optical element 450, refraction can occur. In some cases, the refraction of light can change the direction of travel of the light so that it contacts the opposite sidewall of optical element 450. When this occurs, total internal reflection (TIR) ​​can occur, which can cause the light to reflect back toward the top surface of patterned cover plate 430. An example of light traveling on this path is shown in FIG. Figure 5C 4 is labeled as "Refraction + TIR" in FIG. In some cases, the direction of travel of the light may be altered (e.g., refracted), but the alteration may not be sufficient to cause the light to strike the opposite sidewall of the optical element 450. In this case, the light may be refracted toward the top surface of the patterned cover plate 430 at a shallower angle than the light reflected from the opposite sidewall of the optical element 450. An example of light traveling on this path is shown in FIG. Figure 5C In some embodiments, the optical element 450 can redirect a portion of the light emitted from the LED that is at least 45° from the optical axis N to within 30° of the optical axis N. In some embodiments, the optical element 450 can redirect a portion of the light emitted from the LED that is at least 10° from the optical axis N to more than 30° from the optical axis N.

[0149] refer to Figure 5D , light at a smaller angle (e.g., light having an angle closer to perpendicular to the emitting surface of the LED) can contact the optical element 450 as it leaves the recipient luminescent medium 410. Figure 5C As discussed previously, the difference in refractive index between the materials of the receptor luminescent medium 410 and the optical element 450 can cause the smaller angle light to be refracted when the light contacts the first surface of the optical element 450. However, due to the steeper angle of the smaller angle light, the refraction may not be as good as at the first surface of the optical element 450. Figure 5C , so less (or none) of the lower angle light may strike the opposite sidewall of the optical element 450. Thus, despite the increasing angle relative to the optical axis N, the light may be refracted toward the top surface of the patterned cover plate 430. An example of light traveling on this path is Figure 5D is marked as "Refractive Only".

[0150] As mentioned earlier, Figure 5A-5DThe "yellow" (550) and "blue" (540) designations of light in FIG. 1 are not intended to represent color, but rather the angle of light emitted from the combination of the LED chip 100 and the recipient luminescent medium 110, 410. Light emitted at a greater angle to the optical axis N will travel farther through the recipient luminescent medium 110, 410 and therefore have a proportionally higher component of light that is converted to a different wavelength within the recipient luminescent medium 110, 410. Similarly, light emitted at a smaller angle relative to the optical axis N will have a proportionally smaller component of light that is converted to a different wavelength within the recipient luminescent medium 110, 410. By distributing the two types of light across a wider range of viewing angles, a more consistent CoA can be achieved.

[0151] Fig. 6A , Figure 6B and Figure 6C An example configuration of an optical element 450a according to an embodiment of the present invention is shown. Fig. 6A As shown in FIG. 4 , the optical element 450a may have a substantially conical shape. The conical optical element 450a may protrude from the patterned cover plate 430. In other words, the patterned cover plate 430 may be formed by patterning the cover plate to have the conical optical element 450a protruding therefrom. In some embodiments, the patterned cover plate 430 may be formed by an etching process (e.g., wet etching or dry etching). Fig. 6A The protrusion shown in is used to form the optical element 450a. Figure 6B FIG. 4 is a plan view of an arrangement of conical optical elements 450a on a patterned cover plate 430. In some embodiments, each conical optical element 450a may be separated from adjacent conical optical elements 450a by a pitch Pa. Fig. 6A The conical optical element 450a shown in FIG. 4 includes a linear sidewall, but embodiments of the present invention are not limited thereto. For example, in some embodiments, the sidewall of the optical element 450 including the conical optical element 450a may include a curved and / or nonlinear sidewall 630a, such as Figure 6CAs shown in the profile diagram. In some embodiments, the height of the conical optical element 450a can be from about 1 μm to about 2 μm. The diameter of the base of the conical optical element 450a can be from about 2.2 μm to about 3 μm. The pitch Pa can be between about 2 μm and about 4 μm. In other embodiments, the height of the conical optical element 450a can be from about 0.5 μm to about 4 μm, the diameter of the base of the conical optical element 450a can be from about 1.0 μm to about 4 μm, and the pitch Pa can be between about 1.5 μm and about 8 μm. In some embodiments, the pitch Pa can vary between 0.5 μm and about 10 μm. In some embodiments, the pitch Pa can be based on the size of the conical optical element 450a. For example, in some embodiments, the pitch Pa can be between 0.5 and 10 times the size (e.g., width) of the conical optical element 450a.

[0152] Fig. 7A , Figure 7B and Figure 7C Additional example configurations of optical element 450b according to embodiments of the present invention are illustrated. Fig. 7A As shown in , the optical element 450b may be configured in a substantially quadrilateral pyramid shape. The quadrilateral pyramid optical element 450b may be configured to protrude from the patterned cover plate 430. The base of the quadrilateral pyramid optical element 450b may have, for example, a quadrilateral design having four sides. Figure 7B FIG. 4 shows a plan view of the arrangement of quadrilateral pyramid optical elements 450 b on the patterned cover plate 430 . Each quadrilateral pyramid optical element 450 b may be separated from adjacent quadrilateral pyramid optical elements 450 b by a pitch Pb. Figure 6C As discussed, the sidewalls 630b of the quadrilateral pyramid optical element 450b may be curved and / or non-linear, such as Figure 7C The curve of the side wall 630b can be Figure 6CThe curves of the sidewalls 630a shown in may be the same or different. In some embodiments, the height of the quadrilateral pyramid optical element 450b may be from about 1 μm to about 2 μm. The size (e.g., length or width) of the side of the base of the quadrilateral pyramid optical element 450b may be from about 2.2 μm to about 3 μm. The pitch Pb may be between about 2 μm and about 4 μm. In other embodiments, the height of the quadrilateral pyramid optical element 450a may be from about 0.5 μm to about 4 μm, the diameter of the base of the quadrilateral pyramid optical element 450a may be from about 1.0 μm to about 4 μm, and the pitch Pb may be between about 1.5 μm and about 8 μm. In some embodiments, the pitch Pb may vary from 0.5 μm to about 10 μm. In some embodiments, the pitch Pb may be based on the size of the quadrilateral pyramid optical element 450b. For example, in some embodiments, the pitch Pb may be between 0.5 and 10 times the size (eg, width) of the quadrilateral pyramid optical element 450b.

[0153] Fig. 8A , Figure 8B and 8C Additional example configurations of optical element 450c according to embodiments of the present invention are illustrated. Fig. 8A As shown in , the optical element 450c may be configured in a substantially hexagonal pyramid shape. The hexagonal pyramid optical element 450c may be configured to protrude from the patterned cover plate 430. The base of the hexagonal pyramid optical element 450c may have, for example, a hexagonal design with six sides. Figure 8B FIG. 4 is a plan view of an arrangement of hexagonal pyramid optical elements 450c on a patterned cover plate 430. Each hexagonal pyramid optical element 450c can be separated from adjacent hexagonal pyramid optical elements 450c by a pitch Pc. Figure 6C As discussed, the sidewalls 630c of the hexagonal pyramid optical element 450c can be curved and / or non-linear, such as Figure 8C The curve of the side wall 630c can be Figure 6C The curve of the side wall 630a shown in FIG. Figure 7CThe curve of the sidewall 630b shown in may be the same or different. In some embodiments, the height of the hexagonal pyramid optical element 450c may be from about 1 μm to about 1.5 μm. The widest dimension of the base of the hexagonal pyramid optical element 450c may be from about 1.8 μm to about 2.7 μm. The pitch Pc may be between about 2.4 μm and about 2.8 μm. In other embodiments, the height of the hexagonal pyramid optical element 450a may be from about 0.5 μm to about 3 μm, the diameter of the base of the hexagonal pyramid optical element 450a may be from about 1.0 μm to about 4 μm, and the pitch Pc may be between about 1.5 μm and about 5 μm. In some embodiments, the pitch Pc may vary from 0.5 μm to about 10 μm. In some embodiments, the pitch Pc may be based on the size of the hexagonal pyramid optical element 450c. For example, in some embodiments, the pitch Pc can be between 0.5 and 10 times the size (eg, width) of the hexagonal pyramid optical element 450c.

[0154] Although it has been about Figures 6A-8C Specific shapes are described, but it will be understood that other shapes may be provided for the optical element 450 to provide further embodiments of the present invention. For example, the optical element 450 may be other types of geometric shapes, including pyramids, spheres, ellipsoids, cubes, cylinders, paraboloids, etc., having bases with different numbers of sides. Similarly, the individual optical elements 450 may be arranged on the patterned cover 430 in various ways. For example, the optical elements 450 may be arranged in a grid of various configurations (e.g., squares, rectangles, hexagons, etc.). In addition, the optical elements 450 may be arranged on the patterned cover in an irregular and / or non-periodic arrangement (e.g., randomly patterned, quasi-crystals, etc.). In some embodiments, the optical elements 450 may be arranged at a first position (e.g., an edge or the middle) of the patterned cover 430 in a first arrangement and at a second position (e.g., an edge or the middle) of the patterned cover 430 in a second arrangement. For example, a first position of the patterned overlay 430 may include optical elements 450 arranged in a regular grid, and a second position of the patterned overlay 430 may include optical elements 450 arranged randomly. In some embodiments, a first position of the patterned overlay 430 may include optical elements 450 arranged in a grid having a first configuration (e.g., squares), and a second position of the patterned overlay 430 may include optical elements 450 arranged in a grid having a second configuration (e.g., hexagons). In some embodiments, the optical elements 450 on the patterned overlay 430 may be composed of a variety of shapes and sizes. For example, a first type and / or shape of optical elements 450 (e.g., Figure 6A-6CConical optical element 450a) may be used in a first portion of patterned cover plate 430, and a second type and / or shape of optical element 450 (e.g., Figure 8A-8C Hexagonal pyramid optical elements 450c) may be used in the second portion of the patterned cover plate 430. In some embodiments, the pitch between adjacent optical elements 450 may be between 0.5 and 10 times the size (eg, width) of the optical element 450.

[0155] although Figure 4 An example is illustrated in which the optical element 450 is on the bottom surface of the patterned superstrate 430 (eg, the surface of the patterned superstrate 430 closest to the LED chip 100), but it will be understood that other configurations are possible. Fig. 9A FIG. 9 is a diagram illustrating a semiconductor light emitting device 900 according to an embodiment of the present invention, wherein the optical element 450 is on the top surface of the patterned cover plate 430′. Fig. 9A As shown in FIG. 4 , the bottom surface of the patterned cover plate 430 ′ can be adjacent to the recipient light emitting medium 410 , and the optical element 450 can be placed on the opposite side (eg, the top surface) of the patterned cover plate 430 ′ from the recipient light emitting medium 410 . Figure 4 Like the lighting device 400 of the present invention, the patterned cover plate 430' and the acceptor luminous medium 410 may include a chip cover 420' together, but the present invention is not limited thereto. In some embodiments, the patterned cover plate 430' may be placed on the LED chip 100 separately from the acceptor luminous medium 410. In such an embodiment, the transparent adhesive layer 105 may not be required.

[0156] Fig. 9B It is a graphic Fig. 9A Schematic diagram of the operation of the semiconductor light emitting device 900. Fig. 9B Including Figure 5A and Figure 5B A similar designation of light rays from a point source illustrated as blue (540) or yellow (550) based on the emission angle from an LED is shown in FIG. For the sake of brevity, this description will not be repeated here. Fig. 9B As shown in FIG. 1 , the operation of the semiconductor light emitting device 900 having the optical element 450 on the top surface of the patterned cover plate 430 ' is similar to that of the semiconductor light emitting device having the optical element 450 on the bottom surface of the patterned cover plate 430 ' (eg, Figure 4The operation of the semiconductor light emitting device 400 of the embodiment of the present invention is different from that of the semiconductor light emitting device 400 of the embodiment of the present invention. However, the change in the refractive index of the material between the patterned superstrate 430' and the recipient light emitting medium 410 still causes the reflection within the patterned superstrate 430' to be increased. As a result, the CoA variation of the semiconductor light emitting device 900 is modified compared to conventional devices. In addition, the brightness of the light emitted from the semiconductor light emitting device 900 having the optical element 450 on the top surface of the patterned superstrate 430' can be increased compared to the brightness of other semiconductor light emitting devices.

[0157] Although the previously described embodiments illustrate optical element 450 protruding from patterned superstrate 430 , it will be understood that embodiments of the present invention are not limited thereto. For example, in some embodiments, optical element 450 may be configured as a depression in patterned superstrate 430 . Fig. 10A , Fig. 10B and Fig. 10C The diagrams show the Fig. 6A , Fig. 7A and Fig. 8A Embodiments of optical element 450 are similar in shape to those of , except that optical element 450 is recessed into the surface of patterned cover plate 430 rather than protruding therefrom. For example, Fig. 10A Conical optical elements 450a' are shown recessed into the surface of patterned superstrate 430. Fig. 10B Quadrangular pyramid optical elements 450b' are illustrated as being recessed into the surface of patterned superstrate 430. Fig. 10C A hexagonal pyramid optical element 450c' is illustrated as being recessed into the surface of the patterned cover plate 430. The recessed optical elements 450a', 450b', 450c' may be formed by etching (e.g., via dry or wet etching) a bulk substrate and then slicing the bulk substrate to form the optical elements 450a', 450b', 450c'.

[0158] In such Figure 4 and the device configuration shown in FIG. 9 using a device configuration including a Fig. 10A , Fig. 10B and Fig. 10C A patterned cover plate 430 of a recessed optical element 450 such as the recessed optical element 450 shown in FIG. For example, Fig.11A An example semiconductor light emitting device 1100 is shown, wherein a semiconductor light emitting device 1100 is shown. Figure 4In some embodiments, the recessed optical element 450' is disposed in the bottom surface of the patterned cover plate 430. In some embodiments, the receptor light emitting medium 410 may be within and / or fill the recess of the recessed optical element 450', but the embodiments described herein are not limited thereto. For example, in some embodiments, the recess of the recessed optical element 450' may be configured to include a void therein (e.g., having an air gap). Fig. 11B An example lighting device 1100 ″ is illustrated in which a recessed optical element 450 ″ is in a top surface of a patterned superstrate 430 ″ in a manner similar to FIG. 9 .

[0159] and Figure 4 Like the semiconductor light emitting device 400, Fig.11A and Fig. 11B The patterned cover plate 430, 430' and the acceptor luminescent medium 410 may also form the chip cover 420, 420' together, but the embodiments of the present invention are not limited thereto. In some embodiments, the patterned cover plate 430, 430' may be placed on the LED chip 100 separately from the acceptor luminescent medium 410. In such an embodiment, the transparent adhesive layer 105 may not be required.

[0160] The semiconductor light emitting device according to an embodiment of the present invention can also benefit from the use of two cover plates, at least one of which is a patterned cover plate. By using two cover plates, the optical element can be separated from the recipient light emitting medium. This separation can allow additional reflection of the emitted light within the two cover plates, thereby further improving (e.g., reducing) the CoA variation of the semiconductor light emitting device. Fig. 12A and Fig. 12B An example semiconductor light emitting device 1200 is illustrated in which an optical element 450 is disposed between two superstrate panels. Fig. 12A , the patterned cover plate 430' can be disposed on the recipient light emitting medium 410. The patterned cover plate 430' can be provided with an optical element 450 disposed on the top surface of the patterned cover plate 430'. The optical element 450 can be, for example, Figures 6A-8C Any of the optical elements 450a, 450b, 450c described above, as well as other shapes. In the semiconductor light emitting device 1200, a second cover plate 440 may be disposed on the patterned cover plate 430'. In some embodiments, the patterned cover plate 430' and the second cover plate 440 may be composed of the same material. In some embodiments, the patterned cover plate 430' and the second cover plate 440 may be composed of different materials. By using different materials, the two cover plates may introduce an additional difference between the refractive index of the patterned cover plate 430' and the refractive index of the second cover plate 440, which may introduce additional beneficial adjustments to the CoA of the semiconductor light emitting device 1200.

[0161] Since the optical element 450 protrudes from the patterned cover plate 430', a gap may be formed between the patterned cover plate 430' and the second cover plate 440. In some embodiments, the gap between the patterned cover plate 430' and the second cover plate 440 may be filled with a transparent filler material, such as an acrylic and / or silicone material. In some embodiments, the gap may remain substantially empty, for example, as an air gap.

[0162] Fig. 12B Semiconductor light emitting device 1200 is illustrated wherein second superstrate 440 is placed on recipient light emitting medium 410 and patterned superstrate 430 is placed on second superstrate 440. In this example, optical element 450 protrudes from the bottom surface of patterned superstrate 430 at the interface between patterned superstrate 430 and second superstrate 440.

[0163] like Fig. 12A and Fig. 12B As shown in , the interface between the patterned cover plate 430' and the second cover plate 440 may provide additional structure to promote reflection within the patterned cover plate 430' and / or the second cover plate 440. Figure 4 Like the semiconductor light emitting device 400, Fig. 12A and Fig. 12B The patterned cover plate 430, 430', the second cover plate 440 and the acceptor luminescent medium 410 may together form the chip cover 420, 420', but the embodiments described herein are not limited thereto. In some embodiments, the patterned cover plate 430, 430' may be placed on the LED chip 100 separately from the acceptor luminescent medium 410. In such an embodiment, the transparent adhesive layer 105 may not be required.

[0164] Fig. 12C and Fig.12D An example semiconductor light emitting device 1200 ′ is illustrated in which an optical element 450 ′ is disposed as a recess between two superstrate plates. Fig. 12C Embodiments include Fig. 12A The second cover plate 440 may be similar to the configuration of the patterned cover plate 430', except that the patterned cover plate 430' includes the optical element 450' as a depression rather than a protrusion. Thus, the second cover plate 440 may be on the upper surface of the patterned cover plate 430', and in some embodiments may be flush with the upper surface of the patterned cover plate 430'. Fig.12D Embodiments include Fig. 12B A configuration similar to that of , wherein optical element 450 is positioned in the bottom surface of patterned cover plate 430. Fig. 12C and Fig.12DIn some embodiments, the optical element 450' formed by the recess of the patterned cover plate 430, 430' can be filled with a material (e.g., an acrylic and / or silicone material), or in some embodiments, a void / gap can be left within the optical element 450'.

[0165] Figures 12A-12D An embodiment is illustrated in which a patterned superstrate 430, 430' can be combined with an unpatterned second superstrate 440 to reduce CoA variation of light emitted from a semiconductor light emitting device. In some embodiments, more than one patterned superstrate can be combined within a lighting device. Fig.12E and Fig.12F is a cross-sectional view of a semiconductor light emitting device 1200'' according to an embodiment of the present invention, wherein the semiconductor light emitting device 1200'' includes more than one patterned cover plate. Fig.12E As shown in , more than one patterned cover plate 430 ' can be stacked on top of each other to further adjust the light emitted from the semiconductor light emitting device 1200 ' ' . By using two patterned cover plates 430 ' , light that has passed through the first set of optical elements 450 ' ' of the first patterned cover plate 430 ' ' can be further reflected by the second set of optical elements 450 ' ' of the second patterned cover plate 430 ' . Although Fig.12E The device 1200 ' ' illustrates a stack of two patterned superstrate 430 ' 's including an optical element 450 ' ' as a recess, but it will be understood that a semiconductor light emitting device may similarly utilize more than two patterned superstrate 430 ' s. Similarly, a patterned superstrate including an optical element as a protrusion, such as Figure 4 Those shown in , can also be stacked on top of each other.

[0166] Furthermore, patterned covers utilizing different types of optical elements can be stacked on top of each other. Fig.12F As shown in FIG. 1 , a semiconductor light emitting device 1200 ″ may have a patterned superstrate 430 including protruding optical elements 450 stacked on a patterned superstrate 430 ″ including concave optical elements 450 ″. It will be understood that Fig.12F The stacking order shown in is only an example. In some embodiments, the optical elements of the stacked patterned cover plates can be on shared or opposite surfaces of the stacked patterned cover plates. Fig.12E and Fig.12F Both, the stacked patterned superstrate 430, 430' can be combined with the acceptor light emitting medium 410 to form a chip cover 420', but the embodiments described herein are not limited thereto.

[0167] Figure 12G and Fig.12His a schematic cross-sectional view of a semiconductor light emitting device 1200 ˊ ˊ ˊ having a patterned superstrate 430 ˊ ˊ having optical elements 450 , 450 ˊ on its two major surfaces. Figure 12G As shown in , the semiconductor light emitting device 1200ˊˊˊ may include, for example, a patterned superstrate 430ˊˊ having protruding optical elements 450 on both the upper and lower surfaces of the patterned superstrate 430ˊˊ. Having two sets of optical elements 450 may allow for additional refractive surfaces to further adjust the light reflected by the semiconductor light emitting device 1200ˊˊˊ. Fig.12H An example is shown in which the patterned superstrate 430"" includes optical elements 450"" as recesses on both the upper and lower surfaces of the patterned superstrate 430""". Figure 12G and Fig.12H In addition, the stacked patterned superstrate 430"" and the acceptor light emitting medium 410 may be combined to form a chip cover 420""; however, the embodiments described herein are not limited thereto. Figure 12G and Fig.12H An embodiment is illustrated in which the patterned cover 430'' includes the same type of optical elements 450, 450'', but it will be understood that other configurations are possible. For example, in some embodiments, one surface of the patterned cover 430''' may include the optical elements 450 as protrusions, while another surface may include the optical elements 450'' as depressions. Similarly, in some embodiments, one surface of the patterned cover may include a first shape (e.g., with respect to Figures 6A-8C One surface may include an optical element 450, 450' having one or other of the shapes discussed, while the other surface may include an optical element 450, 450' having a second, different shape.

[0168] Fig.13 A semiconductor light emitting device 1300 is illustrated in which a patterned cover plate 430ˊˊˊ includes an internal optical element 450ˊˊ. The optical element 450ˊˊ may be formed inside the patterned cover plate 430ˊˊˊ rather than on its surface. In some embodiments, the internal optical element 450ˊˊ may be formed by focusing a laser on an internal region of a bulk substrate. The laser may focus energy on an internal region of the bulk substrate, thereby inducing microcracks within the bulk substrate. The microcracks may deform and / or alter the structure of the bulk substrate, thereby forming the internal optical element 450ˊˊ. Thus, the optical element 450ˊˊ may include a structural feature within the patterned cover plate 430ˊˊˊ (e.g., between the top and bottom surfaces of the patterned cover plate 430ˊˊˊ).

[0169] After formation, the bulk substrate can be singulated and placed on LED chips 100 as described herein with respect to other devices (e.g., Figure 4In some embodiments, the internal optical element 450 ˊ ˊ can be formed in the patterned cover plate 430 ˊ ˊ ˊ after the patterned cover plate 430 ˊ ˊ ˊ has been singulated and placed on the LED.

[0170] like Fig.13 As shown in , internal optical element 450 ' ' can provide additional structure to promote reflection within patterned cover plate 430 ' ' ' . Figure 4 Like the semiconductor light emitting device 400, Fig.13 The patterned superstrate 430ˊˊˊ and the acceptor luminescent medium 410 may be combined in an improved chip cover 420ˊˊˊ, but the embodiments described herein are not limited thereto. In some embodiments, the patterned superstrate 430ˊˊˊ and the acceptor luminescent medium 410 may be placed separately on the LED chip 100. In such an embodiment, the transparent adhesive layer 105 may not be required.

[0171] Fig.14 A semiconductor light emitting device 1400 is shown that includes an air gap 1410 between a patterned superstrate 430 and a recipient light emitting medium 410. The semiconductor light emitting device 1400 is similar to Figure 4 The semiconductor light emitting device 1400 is a semiconductor light emitting device, and thus, for the sake of brevity, descriptions of similar elements of the semiconductor light emitting device 1400 will be omitted. The positioning of the air gap 1410 can provide an additional interface between the acceptor light emitting medium 410 and the air gap 1410, which provides an additional refractive index difference. Therefore, light emitted from the acceptor light emitting medium 410 will encounter a first interface having a first refractive index difference between the acceptor light emitting medium 410 and the air gap 1410 and a second interface having a second refractive index difference between the air gap 1410 and the patterned cover plate 430. The air gap 1410 can be created by raising the patterned cover plate 430 above the acceptor light emitting medium 410 using a support structure 1420. Fig.14 An example is illustrated where the support structure 1420 is a riser that supports the patterned superstrate 430 at the sides of the LED chip 100. However, it will be appreciated that other types of support structures 1420 may also create the air gap 1410 without departing from the embodiments described herein.

[0172] Fig.15 The molded lighting device including the lens 1510 is shown. Figure 4Semiconductor light emitting device 400. Semiconductor light emitting device 400. In some embodiments, the material of the lens 1510 can directly contact the upper surface of the patterned cover 430. The material of the lens 1510 can therefore provide a different refractive index for light emitted from the patterned cover 430. Therefore, compared to other configurations (for example, there is an air gap above the patterned cover 430), the configuration of the patterned cover 430 can be configured to take into account the change in refractive index as described herein. In some embodiments, an air gap can be provided between the lens 1510 and the patterned cover 430, for example by using a spacer. Filling material 1520 can be provided at the side of the semiconductor light emitting device 400. In some embodiments, the filling material 1520 can be a reflective material configured to facilitate reflection of light emitted from the semiconductor light emitting device 400. In some embodiments, the filling material 1520 can be an opaque filler. The lens 1510 can be provided to encapsulate the semiconductor light emitting device 400, thereby providing a molded lighting device with reduced CoA variation. Although Fig.15 The use of semiconductor light emitting device 400 is illustrated, but it will be understood that other semiconductor light emitting devices (e.g., semiconductor light emitting devices 1100, 1100', 1200, 1200', 1200'ˊ, 1200"ˊ, 1300, and 1400) may be similarly used without departing from the embodiments described herein.

[0173] Although the previously described embodiments include using the patterned superstrate 430 with a single LED chip 100 , it will be appreciated that the patterned superstrate 430 may also be used in conjunction with a plurality of LED chips 100 . Fig.16 The diagram shows a patterned superstrate 430 used in a semiconductor light emitting device 1600 having a plurality of LED chips 100. Fig.16, a plurality of LED chips 100 may be disposed on a support substrate 160 (e.g., a ceramic substrate). An acceptor luminescent medium 1610 may be provided as an encapsulation filler on the top surface of each of the plurality of LED chips 100. In some embodiments, the acceptor luminescent medium 1610 may be located within a space between adjacent LED chips 100 in the plurality of LED chips 100, and in some embodiments may fill a space between adjacent LED chips 100 in the plurality of LED chips 100. The acceptor luminescent medium 1610 may include a phosphor and / or other material such that the acceptor luminescent medium 1610 may perform conversion of light emitted from the plurality of LED chips 100. As with the previously discussed devices, a patterned superstrate 430 may be placed on the acceptor luminescent medium 1610, and may include an optical element 450 configured to reduce CoA variations of the semiconductor light emitting device 1600. Therefore, as described with respect to a single LED, the patterned superstrate 430 and the acceptor luminescent medium 1610 will perform similar functions to improve CoA variations with respect to the plurality of LED chips 100.

[0174] although Fig.16 A specific embodiment of the optical element 450 is illustrated in which the optical element 450 is presented as protruding from the bottom surface of the patterned cover plate 430, but it will be understood that other embodiments of the patterned cover plate 430, 430', 430'', 430''' may be substituted. Fig.16 The patterned cover plate 430 is provided to provide an additional semiconductor light emitting device according to an embodiment of the present invention. For example, Fig.16 The patterned cover plate 430 may include an optical element 450 on the top surface, the bottom surface, and / or the middle area of ​​the patterned cover plate 430. The optical element 450 may be a variety of shapes, including cones, pyramids, and / or other geometric shapes. The optical element 450 may protrude from the patterned cover plate 430, or may be integrated into the patterned cover plate 430 as a recess.

[0175] like FIG. 17A to FIG. 1 As shown in FIG. 7c, the semiconductor light emitting device according to the embodiment of the present invention can show improved CoA variation compared with the conventional device. Fig.17A and Fig. 17B , the CoA variation of the improved CoA device 1720 including the patterned overlay is compared with the CoA variation of the conventional device 1710 . Figure 17A-Figure 17C The conventional device shown in is such as Figure 2 , where a smooth sapphire superstrate (ie, without patterning and / or optical elements) is placed over the acceptor luminescent medium. Fig.17A Indicates the change of the ccx coordinate of the color with the viewing angle θ (dccx). Fig. 17BIndicates the change of ccy coordinate of color with viewing angle θ (dccy). Figure 3B and Figure 3C As discussed, the performance of conventional device 1710 varies significantly as the viewing angle θ increases relative to an axis normal to the emitting surface of the LED. For example, as the viewing angle θ increases, the deviation in both the ccx and ccy directions increases.

[0176] As in Fig.17A and Fig. 17B As can be seen in the , for substantially all viewing angles within 75 degrees of the axis perpendicular to the light emitting surface of the LED, the semiconductor light emitting device according to an embodiment of the present invention exhibits a significant reduction in the variation in the ccx and ccy components of the emitted light. In fact, for substantially all viewing angles within 75 degrees of the axis perpendicular to the light emitting surface of the LED, both the ccx and ccy components of the emitted light are maintained within a range of 0.01. Moreover, for substantially all viewing angles within 40 degrees of the axis perpendicular to the light emitting surface of the LED, both the ccx and ccy components of the emitted light are maintained within a range of 0.005.

[0177] Fig. 17C The difference in CoA variation for different types of patterned overlays is illustrated. For example, Fig. 17C FIG. 1 illustrates an optical element having a conical shape (e.g., a circular cross section) according to an embodiment of the present invention (e.g., similar to Figure 6A-6C The semiconductor light emitting device 1720a of the embodiment described in the present invention and the hexagonal pyramid optical element according to the embodiment of the present invention (for example, similar to Figure 8A-8C Compared with the semiconductor light emitting device 1720b of the embodiment described above, the CoA performance of the conventional semiconductor light emitting device 1710 is improved. Fig. 17C As can be seen in the , both embodiments 1720a and 1720b provide minimal deviation in the ccy direction compared to conventional device 1710. In the viewing angle range within 60 degrees from the axis perpendicular to the light emitting surface of the LED, although embodiment 1720a using a conical optical element has a slight positive deviation in the ccy component of the emitted light, and embodiment 1720b using a hexagonal pyramid optical element has a slight negative deviation in the ccy component of the emitted light, both embodiments 1720a and 1720b have smaller deviations than conventional device 1710.

[0178] As mentioned previously, some conventional devices utilize diffusers such as fused silica to improve CoA performance. However, such diffusers may reduce the perceived sharpness and contrast of the light. Fig.18A and Fig.18B The illustration shows the reduction in sharpness that may be encountered using a diffuser compared to some embodiments described herein. Fig.18A The figure shows a comparison of the relative brightness between different types of semiconductor light emitting devices. Fig.18A In FIG. 1 , the y-axis indicates the relative brightness of light emitted from the semiconductor light emitting device, and the x-axis indicates the distance (in millimeters) from the center of the semiconductor light emitting device. In an ideal environment, the relative brightness will be uniform across the entire surface of the semiconductor light emitting device. In practice, the relative brightness tends to be maximum at the center portion of the semiconductor light emitting device. Fig.18A A comparison is made between a conventional device 1805 having a fused silica diffuser, a conventional device 1810 having a chip cover including a smooth sapphire cover plate, a device 1820a having a chip cover including a patterned cover plate utilizing conical optical elements according to an embodiment described herein, and a device 1820b having a chip cover including a patterned cover plate utilizing hexagonal pyramid optical elements according to an embodiment described herein. Fig.18B yes Fig.18A A zoomed-in version of the upper portion of the graph. Fig.18B , it can be seen that the conventional devices 1805, 1810 using both diffusers and smooth sapphire begin to lose relative brightness towards the edge of the device relatively earlier than the devices 1820a, 1820b using patterned overlays. In addition, the relative brightness of the devices 1820a, 1820b according to the embodiments described herein include peaks in relative brightness at the outer edges of the semiconductor light emitting device that are higher than the peaks of the conventional devices 1805, 1810. These peaks may be due to an increase in light reflection within the semiconductor light emitting device according to the embodiments described herein.

[0179] Fig.19A and Fig.19B Additional performance comparisons between conventional devices and some of the embodiments described herein are illustrated. Fig.19A The graph shows data related to the contrast ratio of emitted light, where lower numbers are generally considered better. Fig.19A As can be seen in the embodiments 1820a, 1820b using a patterned cover plate as described herein outperform the conventional device using diffuser 1805 and are comparable to the conventional device 1810 using a smooth sapphire cover plate while maintaining the small CoA variation as described herein. Similarly, Fig.19B Data related to the sharpness of emitted light is illustrated, where lower numbers are generally considered better.Here, embodiments 1820a, 1820b using a patterned superstrate as described herein outperform both conventional device 1805 using a diffuser and conventional device 1810 using a smooth sapphire superstrate.

[0180] Fig. 20A and Fig. 20B is a graph showing the CoA performance of a conventional semiconductor light emitting device. Fig. 20A and Fig. 20B The device modeled in the graph is similar in structure to Figure 2 A conventional semiconductor light emitting device includes a chip cover having a smooth sapphire cover plate on a receptor light emitting medium. Fig. 20A The diagram illustrates how the color of light emitted from a conventional semiconductor light emitting device changes with viewing angle. Fig. 20A shows the vˊ coordinate of the emitted light in the 1976 uV CIE chromaticity diagram, which is similar to Figure 1 The 1931 CIE Chromaticity Diagram shown in is similar, but modified so that similar distances on the 1976 uV CIE Chromaticity Diagram represent similar perceived differences in color to a human observer. Fig. 20A As shown in , for a conventional semiconductor light emitting device, as the viewing angle increases from 0 degrees to 80 degrees, the perceived v' of light emitted by the semiconductor light emitting device varies between 0.48 and 0.51. Fig. 20A The small peak or bump in the image near about 0 degrees is probably due to statistical noise in the data. A spherical grid can be used to collect Fig. 20A , and the "bins" used to collect the data get smaller near the poles (at 0 and 180 degrees) - just as the slices produced by the latitude and longitude lines on a global map get smaller near the poles. Relative to the larger boxes near the "equator", smaller bins mean fewer data points and therefore potentially more statistical noise (e.g., lower signal-to-noise ratio), leading to statistical anomalies near the 0 degree mark. Fig. 20B The luminous intensity of a conventional semiconductor light emitting device within the same range of viewing angles is shown. Fig. 20B As can be seen in , the perceived intensity of light emitted by a conventional semiconductor light emitting device also varies with viewing angle.

[0181] Fig.21A and Fig. 21B FIG. 1 is a diagram showing a semiconductor light emitting device according to an embodiment of the present invention. Fig. 20A and Fig. 20B The same performance parameters are shown in Figure 2. Fig.21A and Fig. 21B The semiconductor light emitting device modeled in the graph of includes a patterned sapphire superstrate on a receptor light emitting medium. The patterned superstrate includes an optical element on a lower surface of the patterned superstrate, similar to Figure 4 The device shown in , and the optical element is a conical optical element, as described in this article about Figure 6A-6C discussed. Fig.21A The diagram shows how the color of light emitted from a semiconductor light emitting device changes with viewing angle. Fig.21AIt is shown that the v' coordinate of the light emitted by the semiconductor light emitting device changes only slightly between 0.49 and 0.5 as the viewing angle increases from 0 to 80 degrees. Therefore, the semiconductor light emitting device according to the embodiment of the present invention has a significantly reduced CoA variation compared to the conventional device. Fig.21A Illustration about Fig. 20A Similar statistical anomalies are discussed near the 0 degree mark. Fig. 21B It can be seen that the intensity curve of the light emitted by the semiconductor light emitting device according to the embodiment of the present invention is very similar to the intensity curve of the conventional device. Therefore, the semiconductor light emitting device according to the embodiment of the present invention can reduce the CoA variation of the emitted light without almost affecting the perceived intensity of the emitted light.

[0182] As discussed herein, optical element 450 can be a variety of shapes, including shapes with segmented sides and / or rounded sidewalls. The shape of optical element 450 can be divided into two parts: a base shape (e.g., a cone, a pyramid, a hemisphere, etc.) and deviations from the base shape (intentional or due to etching / processing of patterned features, etc.), such as bows or bends that can be observed along the feature sidewalls when viewed from the profile (see Figure 6C , Figure 7C , Figure 8C ).

[0183] Shapes that rotate smoothly and symmetrically about a major axis (e.g., cones, spheres, etc.) may have beneficial properties over multi-faceted shapes (e.g., pyramids, prisms, etc.) that can improve radial or azimuthal uniformity. For example, if a cone is viewed at an angle to the normal and then rotated about its major axis (from the base to the tip), the profile does not change. This is not the case with a pyramid. Therefore, the pyramid may cause the color uniformity of the portion used as the patterned cover plate 430 to change. For example, if the LED chip 100 and the patterned cover plate 430 including the optical element 450 having a pyramid shape are viewed at an angle to the normal and then rotated, their respective profiles may change at least in part based on the segmented side of the pyramid-shaped optical element 450. In terms of measured data, this may cause the individual curves in the DCCY diagram (representing various measured azimuths) to have significant expansion relative to each other, rather than all being the same. In some embodiments, this variation may mean that the semiconductor light emitting device will pass the DCCY requirement when viewed at certain azimuths, but perform poorly at other azimuths. This phenomenon is Fig.22A and Fig. 22B , which includes an optical element having a circular base (e.g., such as Figure 6A-6C In a semiconductor light emitting device including a conical optical element as shown in FIG. 1 and in an optical element having a hexagonal base (e.g., such as Figure 8A-8C A graph showing the change in CoA in a semiconductor light-emitting device having a hexagonal pyramid optical element (as shown in FIG. 4 ). Fig.22A illustrates the variation of dccx with respect to the angle of emitted light, and Fig. 22B The dccy variation with respect to the angle of the emitted light is shown. Fig.22A and Fig. 22B , individual slices from two samples (A and B) taken at different angles (0°, 45°, 90°, 135°) for a conical optical element (labeled "circular") and a hexagonal pyramid optical element (labeled "hexagonal") are shown. Fig.22A and Fig. 22B As shown in , the CoA performance variation of the conical optical element is smoother than that of the hexagonal pyramid optical element.

[0184] Adding curvature to the profile (or naturally occurring curvature) can help or hurt CoA uniformity, depending on the dimensions of the underlying base shape. Simulations show that curvature can improve CoA for some cone height-to-base ratios, but can actually increase CoA non-uniformity for others. In general, the effects of the two are related, and either can be used (if controllable) to compensate for the negative effects of the other.

[0185] In some embodiments, the optical feature spacing can be used to increase or decrease the effect of the pattern. The flat areas between the optical features may behave the same as an unpatterned cover, so the light emitted through these areas may have poor CoA uniformity. The effect may be most obvious at high angles. In some embodiments, the closer the optical features are together, the less contribution from the unpatterned areas to the emitted light of the semiconductor light emitting device.

[0186] Thus, as described herein, semiconductor light emitting devices utilizing patterned superstrate can provide improvements with respect to CoA variation without degrading other characteristics of light performance. Because patterning the superstrate for the embodiments described herein can use existing equipment with relatively minor modifications to processing techniques, the benefits of CoA variation of the semiconductor light emitting device can be achieved with minimal disruption or increased expense.

[0187] As used herein, the term "semiconductor light emitting device" may include LEDs, laser diodes, and any other semiconductor light emitting devices including one or more semiconductor layers, as well as packaged lamps, bulbs, lamps, etc. including such semiconductor light emitting devices. The semiconductor layers included in these devices may include silicon, silicon carbide, gallium nitride, and / or other semiconductor materials, optional semiconductor or non-semiconductor substrates, and one or more contact layers that may include metal and / or other conductive materials. The expressions "light emitting device" and / or "illumination device" used herein are not limited except that it is a device capable of emitting light.

[0188] Semiconductor light emitting devices according to embodiments of the present disclosure may include LEDs based on Group III-V nitrides (e.g., gallium nitride) fabricated on silicon carbide, sapphire, or gallium nitride substrates, such as various devices manufactured and / or sold by Cree, Inc. of Durham, NC. Such LEDs may (or may not) be configured to operate so that light emission occurs through a substrate in a so-called "flip chip" orientation. Semiconductor light emitting devices according to embodiments of the present disclosure include both: a vertical device having a cathode contact on one side of the LED and an anode contact on the opposite side of the LED; and a device in which both contacts are on the same side of the device. The design and manufacture of semiconductor light emitting devices are well known to those skilled in the art, and further description thereof will be omitted.

[0189] In conjunction with the above description and the accompanying drawings, a number of different embodiments have been disclosed herein. It will be understood that it would be unduly repetitive and confusing to describe and illustrate verbatim every combination and subcombination of these embodiments. Therefore, this specification, including the accompanying drawings, should be interpreted as constituting a complete written description of all combinations and subcombinations of the embodiments described herein and the manner and process of making and using them, and should support the right to claim any such combination or subcombination.

[0190] The present invention has been described above with reference to the accompanying drawings, in which certain embodiments are shown. However, the present disclosure should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. In the accompanying drawings, the thickness of layers and regions is magnified for clarity. Throughout the text, the same reference numerals refer to the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the items listed in question.

[0191] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used herein, the singular forms "a", "an" and "the" are intended to also include plural forms unless the context clearly indicates otherwise. It will be further understood that when used in this specification, the terms "include" and / or "comprise" and their derivatives specify the presence of the elements and / or components, but do not exclude the presence or addition of one or more other elements, components and / or groups thereof.

[0192] It will be understood that when an element, such as a layer, region, or substrate, is referred to as being "on" or extending "on" another element, it may be directly on or extending directly on the other element, or there may also be intervening elements. Conversely, when an element is referred to as extending "directly on" or "directly on" another element, there are no intervening elements. It will also be understood that when an element is referred to as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intervening elements. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements.

[0193] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions and / or layers, these elements, components, regions and / or layers should not be limited by these terms. These terms are only used to distinguish an element, component, region or layer from another element, component, region or layer. Therefore, without departing from the teachings of the present invention, the first element, component, region or layer discussed below may be referred to as the second element, component, region or layer.

[0194] In addition, relative terms such as "lower" or "bottom" and "upper" or "top" may be used herein to describe the relationship of one element to another element as shown in the figures. It will be understood that the relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as being on the "lower" side of another element would be oriented as being on the "upper" side of the other element. Thus, the exemplary term "lower" may encompass both "lower" and "upper" orientations, depending on the particular orientation of the figures.

[0195] Embodiments of the present disclosure are described herein with reference to cross-sectional illustrations, which are schematic illustrations of idealized embodiments (and intermediate structures) of the present disclosure. For clarity, the thickness of the layers and regions in the drawings may be exaggerated. In addition, due to, for example, manufacturing technology and / or tolerances, variations in the illustrated shapes may be expected. Therefore, embodiments of the present disclosure should not be interpreted as being limited to the specific shapes of the regions illustrated herein, but include shape deviations, such as those caused by manufacturing.

[0196] In the drawings and specification, embodiments of the present disclosure have been disclosed, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the present disclosure being set forth in the appended claims.

Claims

1. A semiconductor light emitting device, comprising: Light emitting diode LED chip; Acceptor luminescent medium on LED chip; and a patterned superstrate on the recipient luminescent medium opposite the LED chip, the patterned superstrate comprising a patterned surface configured to reduce the variation of a color point of light emitted by the semiconductor light emitting device with angles away from an optical axis of the LED chip, wherein the patterned surface of the patterned cover plate is on a side of the patterned cover plate facing the acceptor light emitting medium; Wherein the patterned surface is configured to reduce the variation of both ccx and ccy coordinates of light emitted by the semiconductor light emitting device to within 0.01 for substantially all viewing angles within 40 degrees of an optical axis extending through the LED chip and perpendicular to a major surface of the LED chip.

2. The semiconductor light emitting device according to claim 1, wherein: The patterned surface includes a plurality of optical elements.

3. The semiconductor light emitting device according to claim 2, wherein: The plurality of optical elements are configured to reduce an amount of light emitted by the semiconductor light emitting device while reducing a variation in a color point of the light emitted by the semiconductor light emitting device with a viewing angle.

4. The semiconductor light emitting device according to claim 2, wherein: At least one of the plurality of optical elements includes a convex protrusion.

5. The semiconductor light emitting device according to claim 4, wherein: The convex protrusion includes a non-linear sidewall.

6. The semiconductor light emitting device according to claim 2, wherein: At least one of the plurality of optical elements includes a concave recess.

7. The semiconductor light emitting device according to claim 2, wherein: At least one of the plurality of optical elements has a circular cross-section.

8. The semiconductor light emitting device according to claim 2, wherein: At least one of the plurality of optical elements has a polygonal cross-section.

9. The semiconductor light emitting device according to claim 2, wherein: The plurality of optical elements are arranged in a grid on the patterned cover plate.

10. The semiconductor light emitting device according to claim 2, wherein: A surface of the patterned superstrate opposite the patterned surface is a substantially flat surface.

11. The semiconductor light emitting device according to claim 2, wherein: A height of at least one of the plurality of optical elements is between 1 micron and 3 microns, and a width of the at least one of the plurality of optical elements is between 2 μm and 4 μm.

12. The semiconductor light emitting device according to claim 11, wherein: The plurality of optical elements has a pitch between 0.5 μm and 10 μm.

13. The semiconductor light emitting device according to claim 11, wherein: A pitch of the plurality of optical elements is between 0.5 and 10 times the width of a corresponding one of the plurality of optical elements.

14. The semiconductor light emitting device according to claim 2, wherein: The patterned surface is a first patterned surface, wherein the patterned cover plate comprises a second patterned surface on an opposite side of the patterned cover plate to the first patterned surface, and The plurality of optical elements include a first optical element on the first patterned surface and a second optical element on the second patterned surface.

15. The semiconductor light emitting device according to claim 1, wherein: The patterned superstrate is in direct contact with the recipient light emitting medium.

16. The semiconductor light emitting device of claim 1, further comprising an air gap between the patterned superstrate and the recipient light emitting medium.

17. The semiconductor light emitting device according to claim 1, wherein: The patterned cover plate includes a first patterned cover plate, and The semiconductor light emitting device further includes a second cover plate on the first patterned cover plate, wherein the second cover plate has a main surface adjacent to the patterned surface of the first patterned cover plate.

18. The semiconductor light emitting device according to claim 17, wherein: The first patterned cover plate includes a plurality of first optical elements, and The second cover plate includes a second patterned cover plate, and the second patterned cover plate includes a plurality of second optical elements.

19. The semiconductor light emitting device according to claim 17, wherein: The first patterned cover plate comprises a first refractive index, and Wherein the second cover plate comprises a second refractive index different from the first refractive index.

20. The semiconductor light emitting device of claim 1, further comprising an adhesive layer between the recipient luminescent medium and the LED chip.

21. The semiconductor light emitting device according to claim 1, wherein: The patterned cover plate is transparent.

22. The semiconductor light emitting device according to claim 17, wherein: The second superstrate is between the first patterned superstrate and the recipient light emitting medium.

23. A semiconductor light emitting device, comprising: Light emitting diode LED chip; and A chip cover directly mounted on an LED chip, the chip cover comprising: a patterned cover plate comprising a plurality of optical elements; and a receptor luminescent medium on the patterned superstrate, wherein the receptor luminescent medium is between the LED chip and the patterned superstrate, and the plurality of optical elements are on a side of the patterned superstrate facing the receptor luminescent medium; wherein the patterned cover is configured to reduce the variation of both ccx and ccy coordinates of light emitted by the semiconductor light emitting device to within 0.01 for substantially all viewing angles within 40 degrees of an optical axis extending through the LED chip and perpendicular to a major surface of the LED chip.

24. The semiconductor light emitting device according to claim 23, wherein: At least one of the plurality of optical elements includes a convex protrusion.

25. The semiconductor light emitting device according to claim 24, wherein: The convex protrusion includes a non-linear sidewall.

26. The semiconductor light emitting device according to claim 23, wherein: At least one of the plurality of optical elements includes a concave recess.

27. The semiconductor light emitting device according to claim 23, wherein: At least one of the plurality of optical elements has a circular cross-section.

28. The semiconductor light emitting device according to claim 23, wherein: At least one of the plurality of optical elements has a polygonal cross-section.

29. The semiconductor light emitting device according to claim 23, wherein: The plurality of optical elements are arranged in a grid on the patterned cover plate.

30. The semiconductor light emitting device according to claim 23, wherein: The patterned cover plate includes a patterned surface, and Wherein, a surface of the patterned cover plate opposite to the patterned surface is a substantially flat surface.

31. The semiconductor light emitting device according to claim 23, wherein: The patterned superstrate is in direct contact with the recipient light emitting medium.

32. The semiconductor light emitting device of claim 23, further comprising an air gap between the patterned superstrate and the recipient light emitting medium.

33. The semiconductor light emitting device according to claim 23, wherein: The patterned cover plate includes sapphire, silicon carbide, fused silica and / or glass.

34. The semiconductor light emitting device according to claim 23, wherein: The plurality of optical elements are configured to reduce an amount of light emitted by the semiconductor light emitting device while reducing a variation in a color point of the light emitted by the semiconductor light emitting device with a viewing angle.

35. The semiconductor light emitting device according to claim 23, wherein: A height of at least one of the plurality of optical elements is between 1 micron and 3 microns, and a width of at least one of the plurality of optical elements is between 2 μm and 4 μm.

36. The semiconductor light emitting device according to claim 35, wherein: The plurality of optical elements has a pitch between 0.5 μm and 10 μm.

37. The semiconductor light emitting device according to claim 35, wherein: A pitch of the plurality of optical elements is between 0.5 and 10 times the width of a corresponding one of the plurality of optical elements.

38. The semiconductor light emitting device according to claim 23, wherein: The patterned cover plate includes a first patterned cover plate having a patterned surface, and The semiconductor light emitting device further includes a second cover plate on the first patterned cover plate, wherein the second cover plate has a main surface adjacent to the patterned surface of the first patterned cover plate.

39. The semiconductor light emitting device according to claim 38, wherein: The first patterned cover plate includes a plurality of first optical elements, The second cover plate includes a second patterned cover plate, and the second patterned cover plate includes a plurality of second optical elements.

40. The semiconductor light emitting device according to claim 38, wherein: The first patterned cover plate comprises a first refractive index, and Wherein the second cover plate comprises a second refractive index different from the first refractive index.

41. The semiconductor light emitting device of claim 23, further comprising an adhesive layer between the recipient luminescent medium and the LED chip.

42. The semiconductor light emitting device according to claim 23, wherein: The patterned cover plate is transparent.

43. The semiconductor light emitting device according to claim 23, wherein: The patterned cover plate includes a first patterned surface and a second patterned surface, the second patterned surface being on an opposite side of the patterned cover plate from the first patterned surface, and The plurality of optical elements include a first optical element on the first patterned surface and a second optical element on the second patterned surface.

44. The semiconductor light emitting device according to claim 23, wherein: The plurality of optical elements are within the interior of the patterned cover plate between the first major surface and the second major surface of the patterned cover plate.

45. A semiconductor light emitting device, Light emitting diode LED chip; Acceptor luminescent medium on the LED chip; and a patterned superstrate on the recipient luminescent medium opposite the LED chip, the patterned superstrate comprising a patterned surface configured to: reduce variations in both ccx and ccy color coordinates of light emitted by the semiconductor light emitting device to within 0.01 for substantially all viewing angles within 40 degrees of an optical axis extending through the LED chip and perpendicular to a major surface of the LED chip; in, The patterned surface of the patterned superstrate is on a side of the patterned superstrate that faces the recipient light emitting medium.

46. ​​The semiconductor light emitting device according to claim 45, wherein: The receptor luminescent medium includes a phosphor material and a binder material, and Wherein, the difference between the first refractive index of the adhesive material and the second refractive index of the patterned cover plate is at least 0.

3.

47. The semiconductor light emitting device according to claim 45, wherein: The patterned surface includes a plurality of optical elements.

48. The semiconductor light emitting device according to claim 47, wherein: The plurality of optical elements redirect a portion of light emitted from the LED chip that is at least 45° from the optical axis to within 30° of the optical axis extending through the LED chip and perpendicular to a major surface of the LED chip.

49. The semiconductor light emitting device according to claim 47, wherein: The plurality of optical elements redirect a portion of light emitted from the LED chip that is at least 10° from the optical axis to be at least 30° from the optical axis that extends through the LED chip and is perpendicular to a major surface of the LED chip.

50. The semiconductor light emitting device according to claim 47, wherein: At least one of the plurality of optical elements includes a convex protrusion.

51. The semiconductor light emitting device according to claim 50, wherein: The convex protrusion includes a non-linear sidewall.

52. The semiconductor light emitting device according to claim 47, wherein: At least one of the plurality of optical elements includes a concave recess.

53. The semiconductor light emitting device according to claim 47, wherein: At least one of the plurality of optical elements has a circular cross-section.

54. The semiconductor light emitting device according to claim 47, wherein: At least one of the plurality of optical elements has a polygonal cross-section.

55. The semiconductor light emitting device according to claim 47, wherein: A surface of the patterned superstrate opposite the patterned surface is a substantially flat surface.

56. The semiconductor light emitting device according to claim 47, wherein: The plurality of optical elements are configured to reduce an amount of light emitted by the semiconductor light emitting device while reducing a variation in a color point of the light emitted by the semiconductor light emitting device with a viewing angle.

57. The semiconductor light emitting device according to claim 47, wherein: A height of at least one of the plurality of optical elements is between 1 micron and 3 microns, and a width of at least one of the plurality of optical elements is between 2 μm and 4 μm.

58. The semiconductor light emitting device according to claim 57, wherein: The plurality of optical elements have a pitch between 0.5 microns and 10 microns.

59. The semiconductor light emitting device according to claim 57, wherein: A pitch of the plurality of optical elements is between 0.5 and 10 times the width of a corresponding one of the plurality of optical elements.

60. The semiconductor light emitting device according to claim 47, wherein: The plurality of optical elements are arranged in a grid on the patterned cover plate.

61. The semiconductor light emitting device according to claim 60, wherein: The grid is hexagonal.

62. The semiconductor light emitting device according to claim 47, wherein: The plurality of optical elements are arranged in an irregular pattern on the patterned cover plate.

63. The semiconductor light emitting device according to claim 47, wherein the patterned surface is a first patterned surface, in, The patterned cover plate includes a second patterned surface on an opposite side of the patterned cover plate from the first patterned surface, and The plurality of optical elements include a first optical element on the first patterned surface and a second optical element on the second patterned surface.

64. The semiconductor light emitting device according to claim 45, wherein: The patterned surface is configured to reduce variations in both ccx and ccy coordinates of light emitted by the semiconductor light emitting device to within 0.005 for substantially all viewing angles within 40 degrees of an optical axis extending through the LED chip and perpendicular to a major surface of the LED chip.

65. The semiconductor light emitting device according to claim 45, wherein: The patterned cover plate is transparent.

66. The semiconductor light emitting device of claim 45, wherein the patterned superstrate directly contacts the recipient light emitting medium.

67. The semiconductor light emitting device of claim 45, further comprising an air gap between the patterned superstrate and the recipient light emitting medium.

68. The semiconductor light emitting device according to claim 45, wherein: The patterned cover plate includes sapphire, silicon carbide, fused silica and / or glass.

69. The semiconductor light emitting device according to claim 45, wherein: The patterned cover plate includes a first patterned cover plate, and The semiconductor light emitting device further includes a second cover plate on the first patterned cover plate, wherein the second cover plate has a main surface adjacent to the patterned surface of the first patterned cover plate.

70. The semiconductor light emitting device according to claim 69, wherein: The first patterned cover plate includes a plurality of first optical elements, and The second cover plate includes a second patterned cover plate, and the second patterned cover plate includes a plurality of second optical elements.

71. The semiconductor light emitting device according to claim 69, wherein: The first patterned cover plate comprises a first refractive index, and Wherein the second cover plate comprises a second refractive index different from the first refractive index.

72. The semiconductor light emitting device according to claim 69, wherein: The second superstrate is between the first patterned superstrate and the recipient light emitting medium.

Images