This invention relates to the field of lasers, light-emitting diodes (LEDs), and light sources, and more specifically to a method and hybrid light source that includes LED and laser-pumped phosphor light sources combined together to provide light-intensity profiles suitable for various headlight-illumination ranges, wherein, in some embodiments, the light is projected using, e.g., a multiple-mirror DMD (digital micromirror device) with various projected patterns, for increased safety.
Road safety has become an important subject to be addressed by automotive lighting, including projection of symbols, dimming headlights in response to the approach of oncoming vehicles, increased output for pedestrians, and other safety purposes. All these functions can be done using active imagers, such that the desired or required light pattern can be projected. One major obstacle is the differing brightness requirements of low-beam, high-beam, and extreme-high-beam automotive headlighting. At this time, there is no single light source that can achieve such multiple requirements using a single imager chip, such as a Texas Instruments' DLP® DMD. As a result, many new automobiles are designed with multiple headlights, one for low beam, one for high beam, and one for extreme high beam. Having three or more headlights on left and right sides is not uncommon, and may be found in many new automobiles, such as those shown in car shows. On the other hand, automobile designers often do not like to see headlights, as they disturb the “profiles” and the “look” of automobiles. As a result, there have been movable headlight covers in the past, to cover the large headlights. Recent headlight designs are targeted for very low and extremely low profiles. Total height in the range of 10 mm has been shown and designed. Such designs, however, still require multiple headlights to provide the various ranges of illumination mentioned above.
U.S. Pat. No. 4,520,116 issued to Gentilman et al. on May 28, 1985 with the title “Transparent aluminum oxynitride and method of manufacture” and is incorporated herein by reference. U.S. Pat. No. 4,520,116 describes a polycrystalline cubic aluminum oxynitride having a density of at least 98% of theoretical density, and being transparent to electromagnetic radiation in the wavelength range from 0.3 to 5 micrometers with an in-line transmission of at least 20% in this range. A method of preparing the optically transparent aluminum oxynitride is also provided including the steps of forming a green body of substantially homogeneous aluminum oxynitride powder and pressureless sintering said green body in a nitrogen atmosphere and in the presence of predetermined additives which enhance the sintering process. Preferred additives are boron and yttrium in elemental or compound form.
U.S. Pat. No. 4,686,070 issued to Maguire, et al. on Aug. 11, 1987 with the title “Method of producing aluminum oxynitride having improved optical characteristics” and is incorporated herein by reference. U.S. Pat. No. 4,686,070 describes a method of preparing substantially homogeneous aluminum oxynitride powder that includes the steps of reacting gamma aluminum oxide with carbon in the presence of nitrogen, and breaking down the resulting powder into particles in a predetermined size range. A method of preparing a durable optically transparent body from this powder is also provided that includes the steps of forming a green body of substantially homogeneous cubic aluminum oxynitride powder and sintering said green body in a nitrogen atmosphere and in the presence of predetermined additives which enhance the sintering process. Preferred additives are boron, in elemental or compound form, and at least one additional element selected from the group of yttrium and lanthanum or compounds thereof. The sintered polycrystalline cubic aluminum oxynitride has a density greater than 99% of theoretical density, an in-line transmission of at least 50% in the 0.3- to 5-micron range, and a resolving angle of 1 mrad or less.
There remains a need in the art for methods and apparatus to better control the brightness of automotive headlight beams, and to provide the ability to dynamically reshape various portions of such vehicle headlight beams.
In some embodiments, the present invention provides a hybrid light source with LED and laser-pumped-phosphor elements combined together to provide light-intensity profiles for various ranges required in automotive driving, with the output beam projected using a single digital micromirror device (DMD), with the ability to project patterns, for increased safety.
FIG. 8A1 is a side-cross-sectional-view block diagram of an LED/laser-pumped-phosphor light source assembly 801, according to some embodiments of the present invention.
FIG. 8A2 is a plan-view block diagram of LED/laser-pumped-phosphor light source assembly 801.
FIG. 8B1 is a side-cross-sectional-view block diagram of an LED/laser-pumped-phosphor light source assembly 802, according to some embodiments of the present invention.
FIG. 8B2 is a plan-view block diagram of LED/laser-pumped-phosphor light source assembly 802.
FIG. 8C1 is a side-cross-sectional-view block diagram of an LED/laser-pumped-phosphor light source assembly 803, according to some embodiments of the present invention.
FIG. 8C2 is a plan-view block diagram of LED/laser-pumped-phosphor light source assembly 803.
FIG. 8D1 is a side-cross-sectional-view block diagram of an LED/laser-pumped-phosphor light source assembly 804, according to some embodiments of the present invention.
FIG. 8D2 is a plan-view block diagram of LED/laser-pumped-phosphor light source assembly 804.
FIG. 8E1 is a side-cross-sectional-view block diagram of an LED/laser-pumped-phosphor light source assembly 805, according to some embodiments of the present invention.
FIG. 8E2 is a plan-view block diagram of LED/laser-pumped-phosphor light source assembly 805.
Although the following detailed description contains many specifics for the purpose of illustration, a person of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the invention. Specific examples are used to illustrate particular embodiments; however, the invention described in the claims is not intended to be limited to only these examples, but rather includes the full scope of the attached claims. Accordingly, the following preferred embodiments of the invention are set forth without any loss of generality to, and without imposing limitations upon the claimed invention. Further, in the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. The embodiments shown in the Figures and described here may include features that are not included in all specific embodiments. A particular embodiment may include only a subset of all of the features described, or a particular embodiment may include all of the features described.
The leading digit(s) of reference numbers appearing in the Figures generally corresponds to the Figure number in which that component is first introduced, such that the same reference number is used throughout to refer to an identical component which appears in multiple Figures. Signals and connections may be referred to by the same reference number or label, and the actual meaning will be clear from its use in the context of the description.
In smart automotive headlight applications, in order to provide a wide field of view (FOV) while maintaining high on-center brightness, the illumination source luminance for the on-center portion of the FOV must increase in proportion to the relative FOV area increase. Otherwise, the hot-spot brightness will fall in inverse proportion to the area increase of the total FOV covered by the digital micromirror device (DMD). Effectively, the area dilution of the brightness from increasing the FOV must be counteracted by an increase in source luminance (for the center hot-spot section only). For example, if only 1% of the total area at the center needs to have a higher brightness, without a hot spot it would require the whole area to have a higher brightness, increasing the total output power, making it difficult or impossible to implement (within commercialization constraints such as size, heat-dissipation capability and/or cost). This invention discloses an optical configuration in which the center portion of the LED is pumped using a laser such that a hot spot is formed in the center section of the output illumination, with a sharp roll-off to a relatively lower luminance in outer sections of the LED output illumination.
In some embodiments, phosphor layer 112 is in direct contact with LED 122 such as shown in phosphor layer 212 and LED 222 of
In some embodiments, the light-intensity profile 203 or 204 on the DMD 114 with the selectively activatable hot spot 242 is then projected (using projection optics, not shown here in
In some embodiments, light beam 343 is imaged onto DMD 314, which in some embodiments, includes a plurality of individually activatable micromirrors, generating an output beam 344 that is used to provide a smart headlight with a selectably activated hot spot for the high beam. In some embodiments, light source 301 has white-LED assembly 323, collimating-lens assembly 331, pumping laser 321, and blue-reflecting mirror 313 housed inside enclosure 315, which also functions as a heatsink. In some embodiments, transparent window 318 seals enclosure 315 to protect the inside structure of light source 301 from dust, moisture, and corrosion. In some embodiments, coupling lens 332 is used to image the LED/laser/phosphor light onto DMD 314 through the TIR prism assembly 340, with the output 344 of the DMD 314 projected to the roadway, optionally using optional projection-lens assembly 350 (which includes one or more lenses; in other embodiments, projection-lens assembly 350 is replaced by a concave projection reflector assembly (not shown)). In various embodiments, any of the LED structures shown in
FIG. 8A1 is a side-cross-sectional-view block diagram of an LED/laser-pumped-phosphor light source assembly 801, according to some embodiments of the present invention. For simplicity, clarity and generality, the one or more laser beams that pump the top phosphor are shown schematically as laser beam 841 in FIGS. 8A1, 8B1, 8C1, 8D1, and 8E1.
In some embodiments, assembly 801 includes a blue-light LED 822 affixed to heatsink 823, a phosphor layer 812 affixed to blue-light LED 822, and a crystal phosphor layer 851 affixed to phosphor layer 812. As compared to
FIG. 8A2 is a plan-view block diagram of LED/laser-pumped-phosphor light source assembly 801.
FIG. 8B1 is a side-cross-sectional-view block diagram of an LED/laser-pumped-phosphor light source assembly 802, according to some embodiments of the present invention. In some embodiments, LED/laser-pumped-phosphor light source assembly 802 includes a blue-light LED 822 affixed to heatsink 823, a phosphor layer 812 affixed to blue-light LED 822, and a crystal phosphor 852 affixed to heat-conducting structures 853 that are affixed to heatsink 823 and separated by an offset distance to the sides of phosphor layer 812. Heat-conducting structures 853 are provided to provide a heat-conduction path from crystal phosphor plate 852 to heatsink 823, and are sized such that crystal phosphor plate 852 is separated by a gap 854 (of air or other gas or a vacuum) from phosphor layer 812. In this configuration, the original LED 822 and its phosphor layer 812 are not physically “touched” by the additional components 852 and 853, thus preserving the integrity of the original assembled LED 822 and its phosphor layer 812. There has been a tremendous amount of research and development done in improving the performance of white LEDs, and it is important to capitalize on these development efforts when making improvements. With a small gap 854 between the standard white LED structure 812/822 and the crystal phosphor plate 852, the best commercially available LED can be used, providing the best possible system for this “hot spot” LED assembly 802 using laser pumping. In a manner similar to the white LED 812/822 shown in
FIG. 8B2 is a plan-view block diagram of LED/laser-pumped-phosphor light source assembly 802.
FIG. 8C1 is a side-cross-sectional-view block diagram of an LED/laser-pumped-phosphor light source assembly 803, according to some embodiments of the present invention. In some embodiments, assembly 803 includes a blue-light LED 822 affixed to heatsink 823, a phosphor layer 812 affixed to blue-light LED 822, and a crystal phosphor plate 855 that is smaller than phosphor layer 812 and affixed to a portion of phosphor layer 812. As compared to FIG. 8A1, LED/laser-pumped-phosphor light source assembly 803 has the additional layer of crystal phosphor 855 affixed on top of a portion of the phosphor layer 812, which is deposited on blue-light LED 822. In some embodiments, assembly 803 is substantially equivalent to assembly 801 of FIG. 8A1, except that the additional layer of crystal phosphor 855 covers only a portion (in some embodiments, less than half) of the outer surface of phosphor layer 812.
FIG. 8C2 is a plan-view block diagram of LED/laser-pumped-phosphor light source assembly 803.
FIG. 8D1 is a side-cross-sectional-view block diagram of an LED/laser-pumped-phosphor light source assembly 804, according to some embodiments of the present invention. In some embodiments, assembly 804 includes a blue-light LED 822 affixed to heatsink 823, a phosphor layer 812 affixed to, or deposited on, blue-light LED 822, a transparent heatsink window 856 affixed to a heat-conductive surrounding wall 853 that surrounds a perimeter of (but is separated by a gap from) blue-light LED 822 and phosphor layer 812, and a crystal phosphor plate 855 that is smaller than phosphor layer 812 and affixed to a portion of transparent heatsink layer 856. As compared to FIG. 8A1, LED/laser-pumped-phosphor light source assembly 804 has the additional layer of crystal phosphor 855 affixed on top of a portion of transparent heatsink layer 856, which covers blue-light LED 822 and phosphor layer 812. In some embodiments, assembly 804 is substantially equivalent to assembly 802 of FIG. 8B1, except that heat-conductive surrounding wall 853 surrounds the entire perimeter of (but is separated by a gap from) blue-light LED 822 and phosphor layer 812, and is covered and sealed by transparent heatsink window 856, thus sealing that blue-light LED 822 and phosphor layer 812; and the additional crystal phosphor plate 855 covers only a portion (in some embodiments, less than half) of the outer surface of phosphor layer 812, from which it is separated by transparent heatsink window 856. In some embodiments, transparent heatsink window 856 is made of sapphire, quartz, or other suitable material, such that blockage of light emitted from the LED is minimized. In some embodiments, transparent heatsink 855 is in turn mounted on heatsink wall 853 around LED assembly 822-812, such that heat from phosphor plate 856 is conducted away to LED heatsink 823 through transparent heatsink window 856. In some embodiments, transparent heatsink window 856 is made of a transparent heatsink material such as synthetic diamond or aluminum oxynitride (AlON ceramic, such as ALON-brand by Surmet Corp., or such as described in U.S. Pat. No. 4,520,116 by Gentilman et al. titled “Transparent aluminum oxynitride and method of manufacture” or U.S. Pat. No. 4,686,070 by Maguire, et al. titled “Method of producing aluminum oxynitride having improved optical characteristics,” or the like). In other embodiments, where a sealed compartment is not required, transparent heatsink layer 856 can use a perforated metal such as an aluminum honeycomb plate, or aluminum sheet having etched or punched holes therethrough, or the like.
FIG. 8D2 is a plan-view block diagram of LED/laser-pumped-phosphor light source assembly 804.
FIG. 8E1 is a side-cross-sectional-view block diagram of an LED/laser-pumped-phosphor light source assembly 805, according to some embodiments of the present invention. In some embodiments, assembly 805 includes a blue-light LED 822 affixed to heatsink 823, a phosphor layer 812 affixed to, or deposited on, blue-light LED 822, a cantilevered heatsink platform 857 affixed to a heat-conductive wall 858 that is near a perimeter of (but that is separated by a gap from) blue-light LED 822 and phosphor layer 812, and a crystal phosphor plate 855 that is smaller than phosphor layer 812 and affixed to a portion of heatsink platform 857 which is suspended and separated above phosphor layer 812. In some embodiments, assembly 805 includes a reflective crystal phosphor plate 855 placed on top of a cantilevered heatsink 857-858 connected to the LED heatsink 823 around LED 822 and its phosphor layer 812, such that the heat generated from the reflective crystal phosphor plate 855 is dissipated to heatsink 823. There is a small gap 859 between the crystal phosphor plate 855's heatsink 857-858 and LED assembly 812-822, and crystal phosphor plate 855.
In another embodiment, phosphor plate 855 (which, in some embodiments, may be a crystal phosphor or other phosphor-containing layer) is partially transparent and mounted on a transparent heatsink 857, such as sapphire, quartz, synthetic diamond, or other suitable material, such that part of the LED emission (e.g., in some embodiments, blue light from LED 822 and yellow light from phosphor layer 812) is transmitted through phosphor plate 855, increasing the output at the phosphor-plate area. In this case, phosphor plate 855 together with the original LED's phosphor layer 812 form a composite layer, such that the original LED's phosphor layer 812 absorbs most of the LED blue light from LED 822, with very little absorbed by phosphor plate 855. At the same time, most of the laser light is absorbed by the phosphor plate 855 and very little is absorbed by the LED's phosphor layer 812. This combination allows the use of high-efficiency LED phosphor 812 for broad-area emission and the use of high-temperature phosphor plate 855 for small-spot emission. As compared to LED/laser-pumped-phosphor light source assembly 803 of FIG. 8C1, LED/laser-pumped-phosphor light source assembly 805 has the additional layer of crystal phosphor 855 affixed on top of a portion of heatsink platform 857, which covers a small portion of blue-light LED 822 and phosphor layer 812. In some embodiments, heatsink platform 857 is made of a metal with high heat conductivity, and has a highly reflective upper surface to reflect any downward-directed pump light or wavelength-converted yellow light back upward into or through phosphor plate 855. In other embodiments, heatsink platform 857 is a transparent plate such as transparent heatsink layer 856 described above for FIGS. 8D1 and 8D2. In some embodiments, assembly 805 is substantially equivalent to assembly 803 of FIG. 8C1, except that heat-conductive wall 858 that is near the perimeter of (but separated by a gap from) blue-light LED 822 and phosphor layer 812 holds cantilevered heatsink platform 857, thus separating, by a small gap 859, the additional crystal phosphor plate 855 from blue-light LED 822 and phosphor layer 812. In some embodiments, cantilevered heatsink platform 857 and crystal phosphor plate 855 cover only a portion (in some embodiments, less than half) of the outer surface of phosphor layer 812.
FIG. 8E2 is a plan-view block diagram of LED/laser-pumped-phosphor light source assembly 805.
Continuing,
In order to provide the automotive-headlight-intensity profile required, the light source of some embodiments of the present invention provides higher intensity at the top center of the headlight beam, and a more uniform, lower intensity for the rest of the area.
In some embodiments, a scene sensor 1695 is configured to actively (e.g., using LiDAR or the like) and/or passively (using a camera or the like) sense the environment 1600 around the vehicle in which DMD-based LED/laser-pumped-phosphor light source 1601 is housed, and the received signals or data 1694 received by sensor 1695 are processed into sensed data 1696 and operatively coupled to processor 1690, which then adjusts the shape, direction and/or intensity of various low-beam, high-beam and/or extreme-high-beam portions of headlight beam 1643 as described above.
In some embodiments, the present invention provides a first apparatus (such as illustrated in
In some embodiments of the first apparatus, the LED source further includes: a heatsink; a blue-emitting LED, mounted to the heatsink, wherein the blue-emitting LED outputs blue-LED pump light having LED pump wavelengths; and a phosphor layer located on the blue-emitting LED and operatively coupled to receive the blue-LED pump light and to wavelength-convert a portion of the blue-LED pump light to wavelength-converted LED light having longer wavelengths than the LED pump wavelengths.
Some embodiments of the first apparatus further include a pump laser that outputs a laser beam having a pump-laser wavelength, wherein the laser-pumped phosphor material is a crystal-phosphor plate operatively coupled to receive the laser beam and configured to wavelength-convert a portion of the laser-beam pump light to wavelength-converted laser light having longer wavelengths than the pump-laser wavelength.
In some embodiments of the first apparatus, the LED source further includes: a first heatsink, a blue-emitting LED, mounted to the heatsink, wherein the blue-emitting LED outputs blue-LED pump light having LED pump wavelengths, and a first phosphor layer located on the blue-emitting LED and operatively coupled to receive the blue-LED pump light and wavelength-convert a portion of the blue-LED pump light to wavelength-converted LED light having longer wavelengths than the LED pump wavelengths; and the laser-pumped phosphor material is a crystal-phosphor plate that is mounted in contact with the first phosphor layer and that covers at least a portion of a surface of the first phosphor layer.
In some embodiments of the first apparatus, the LED source further includes: a first heatsink; a blue-emitting LED, mounted to the heatsink, wherein the blue-emitting LED outputs blue-LED pump light having LED pump wavelengths; and a first phosphor layer located on the blue-emitting LED and operatively coupled to receive the blue-LED pump light and wavelength-convert a portion of the blue-LED pump light to wavelength-converted LED light having longer wavelengths than the LED pump wavelengths; and the laser-pumped phosphor material is a crystal-phosphor plate that is mounted in contact with, and covering no more than 50% of, a surface of the first phosphor layer. In some such embodiments, the crystal-phosphor plate covers no more than 40% of the surface of the first phosphor layer. In some such embodiments, the crystal-phosphor plate covers no more than 30% of the surface of the first phosphor layer. In some such embodiments, the crystal-phosphor plate covers no more than 20% of the surface of the first phosphor layer. In some such embodiments, the crystal-phosphor plate covers no more than 10% of the surface of the first phosphor layer.
In some embodiments of the first apparatus, the LED source further includes: a first heatsink; a blue-emitting LED, mounted to the heatsink, wherein the blue-emitting LED outputs blue-LED pump light having LED pump wavelengths; and a first phosphor layer located on the blue-emitting LED and operatively coupled to receive the blue-LED pump light and wavelength-convert a portion of the blue-LED pump light to wavelength-converted LED light having longer wavelengths than the LED pump wavelengths; and the laser-pumped phosphor material is a crystal-phosphor plate that is mounted to a thermally conductive structure that is in contact with the first heatsink but separated from the blue-emitting LED and the first phosphor layer by a gap, and wherein the crystal-phosphor plate covers an entirety of a surface of the first phosphor layer.
In some embodiments of the first apparatus, the LED source further includes: a first heatsink; a blue-emitting LED, mounted to the heatsink, wherein the blue-emitting LED outputs blue-LED pump light having LED pump wavelengths; and a first phosphor layer located on the blue-emitting LED and operatively coupled to receive the blue-LED pump light and wavelength-convert a portion of the blue-LED pump light to wavelength-converted LED light having longer wavelengths than the LED pump wavelengths; and the laser-pumped phosphor material is a crystal-phosphor plate that is mounted to a thermally conductive structure that is in contact with the first heatsink but separated from the blue-emitting LED and the first phosphor layer by a gap, and wherein the crystal-phosphor plate covers less than 50% of a surface of the first phosphor layer. In some such embodiments, the crystal-phosphor plate covers no more than 40% of the surface of the first phosphor layer. In some such embodiments, the crystal-phosphor plate covers no more than 30% of the surface of the first phosphor layer. In some such embodiments, the crystal-phosphor plate covers no more than 20% of the surface of the first phosphor layer. In some such embodiments, the crystal-phosphor plate covers no more than 10% of the surface of the first phosphor layer.
In some embodiments of the first apparatus, the projection optics further includes: coupling optics operatively coupled to receive light from the LED light source and the laser-pumped phosphor material; a total-internal-reflection (TIR) prism assembly (e.g., assembly 340 of
In some embodiments of the first apparatus, the projection optics further includes: coupling optics operatively coupled to receive light from the LED light source and the laser-pumped phosphor material; a total-internal-reflection (TIR) prism assembly operatively coupled to receive light transferred from the coupling optics; and a concave projection-reflector assembly operatively coupled to receive light redirected by the TIR prism assembly and configured to project a headlight beam based on the received light from the TIR prism assembly.
Some embodiments of the first apparatus further include a controller (such as shown in
Some embodiments of the first apparatus further include a vehicle (such as shown in
In some embodiments, the present invention provides a second apparatus (such as illustrated in FIG. 8A1, 8B1, 8C1, 8D1, 8E1, 8F, or 8G) that includes a light-source assembly, wherein the light-source assembly includes: a first heatsink; a first light-emitting diode (LED) light source affixed to the heatsink and configured to emit LED pump light having wavelengths in a first wavelength range; a first phosphor layer affixed to the first LED light source and configured to absorb at least a portion of the LED pump light such that the first phosphor layer outputs a full-area illumination that is a combination of wavelength-converted LED light having wavelengths in a second wavelength range and an unconverted portion of the LED pump light having wavelengths in the first wavelength range; and a laser-pumped second phosphor layer thermally coupled to the heatsink, wherein the laser-pumped second phosphor layer is operatively coupled to receive laser pump light and output wavelength-converted laser light such that a hotspot illumination is generated within the full-area illumination of the first phosphor layer.
In some embodiments of the second apparatus, the first wavelength range is about 420 nanometers (nm) to about 490 nm, inclusive, and wherein the second wavelength range is about 560 nm to about 660 nm, inclusive.
In some embodiments of the second apparatus, the second phosphor layer is a crystal phosphor layer.
Some embodiments of the second apparatus further include a vehicle, wherein the light-source assembly is mounted to the vehicle and controlled to provide smart headlight functions.
Some embodiments of the second apparatus further include a digital micromirror device (DMD) operatively coupled to receive the full-area illumination and the hot-spot illumination, wherein the DMD includes a plurality of micromirrors, wherein each of the plurality of micromirrors of the DMD is configured to selectively reflect light in one of a plurality of directions; and projection optics operatively coupled to receive light selectively reflected by the DMD and configured to project the received light as a beam having a shaped illumination intensity pattern.
In some embodiments of the second apparatus, the second phosphor layer is fused directly to the first phosphor layer.
Some embodiments of the second apparatus further include one or more heat-conducting structures coupled to both the heatsink and the second phosphor layer such that the one or more heat-conducting structures provide a heat-conduction path from the second phosphor layer to the heatsink, wherein the one or more heat-conducting structures are separated by an offset distance from sides of the first phosphor layer, and wherein the one or more heat-conducting structures are sized such that the second phosphor layer is separated from a major face of the first phosphor layer by a gap.
In some embodiments of the second apparatus, the second phosphor layer is fused directly to a first portion of the first phosphor layer.
In some embodiments of the second apparatus, the first phosphor layer has a first area, wherein the second phosphor layer has a second area, wherein the second area is smaller than the first area, and wherein the second phosphor layer is fused directly to a first portion of the first phosphor layer.
Some embodiments of the second apparatus further include a heat-conductive wall thermally coupled to the heatsink, wherein the heat-conductive wall surrounds a perimeter of the first LED light source and the first phosphor layer, wherein the heat-conductive wall is separated from the perimeter of the first LED light source and the first phosphor layer by a gap; and a transparent heatsink window, wherein the transparent heatsink window is thermally coupled to the heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer is conducted to the heatsink through the transparent heatsink window and the heat-conductive wall.
Some embodiments of the second apparatus further include a heat-conductive wall thermally coupled to the heatsink, wherein the heat-conductive wall surrounds at least a portion of a perimeter of the first LED light source and the first phosphor layer, wherein the heat-conductive wall is separated from the perimeter of the first LED light source and the first phosphor layer by a gap; and a transparent heatsink window, wherein the transparent heatsink window is coupled to the heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer is conducted to the heatsink through the transparent heatsink window, wherein the transparent heatsink window separates the first phosphor layer from the second phosphor layer, wherein the first phosphor layer has a first area, wherein the second phosphor layer has a second area, and wherein the second area is smaller than the first area.
Some embodiments of the second apparatus further include a heat-conductive wall thermally coupled to the heatsink, wherein the heat-conductive wall surrounds a perimeter of the first LED light source and the first phosphor layer, wherein the heat-conductive wall is separated from the perimeter of the first LED light source and the first phosphor layer by a gap; and a transparent heatsink window, wherein the transparent heatsink window is thermally coupled to the heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer is conducted to the heatsink through the transparent heatsink window and the heat-conductive wall, wherein the transparent heatsink window is made of a material that includes aluminum oxynitride (AlON).
Some embodiments of the second apparatus further include a first heat-conductive wall thermally coupled to the heatsink, wherein the first heat-conductive wall is separated by an offset distance from a first side of the first phosphor layer; and a cantilevered heatsink platform coupled to both the first heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer flows through the cantilevered heatsink platform and the first heat-conductive wall to the heatsink, wherein the cantilevered heatsink platform is suspended and separated above the first phosphor layer.
Some embodiments of the second apparatus further include a first heat-conductive wall thermally coupled to the heatsink, wherein the first heat-conductive wall is separated by an offset distance from a first side of the first phosphor layer; and a cantilevered heatsink platform coupled to both the first heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer flows through the cantilevered heatsink platform and the first heat-conductive wall to the heatsink, wherein the cantilevered heatsink platform is suspended and separated above the first phosphor layer, wherein the first phosphor layer has a first area, wherein the second phosphor layer has a second area, and wherein the second area is smaller than the first area.
Some embodiments of the second apparatus further include a first heat-conductive wall thermally coupled to the heatsink, wherein the first heat-conductive wall is separated by an offset distance from a first side of the first phosphor layer; and a cantilevered transparent heatsink coupled to both the first heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer flows through the cantilevered transparent heatsink and the first heat-conductive wall to the heatsink, wherein the cantilevered transparent heatsink is suspended and separated above the first phosphor layer, wherein the first phosphor layer has a first area, wherein the second phosphor layer has a second area, and wherein the second area is smaller than the first area.
In some embodiments of the second apparatus, the first LED light source is one of a plurality of LED light sources, wherein each respective LED light source of the plurality of LED light sources includes a corresponding first phosphor layer affixed to the respective LED light source, wherein the second phosphor layer is a reflective phosphor plate fused directly to at least a first one of the plurality of LED light sources.
In some embodiments of the second apparatus, the first LED light source is one of a plurality of LED light sources, wherein each respective LED light source of the plurality of LED light sources includes a corresponding first phosphor layer affixed to the respective LED light source, wherein the second phosphor layer is a reflective phosphor plate fused directly to at least a first one of the plurality of LED light sources, the light-source assembly further including: one or more lasers configured to optically pump the reflective phosphor plate, wherein the one or more lasers are supplied by an electric current; and a safety circuit integrated into the reflective phosphor plate and operatively coupled to the one or more lasers, wherein the safety circuit is configured to interrupt the electric current supplied to the one or more lasers when the reflective phosphor plate is broken.
In some embodiments, the present invention provides a third apparatus (such as illustrated in FIG. 8A1, 8B1, 8C1, 8D1, 8E1, 8F, or 8G) that includes a first heatsink; a first light-emitting diode (LED) light source affixed to the heatsink; a first phosphor layer affixed to the first LED light source; and a laser-pumped second phosphor layer thermally coupled to the heatsink, wherein the laser-pumped second phosphor layer is a crystal phosphor layer.
In some embodiments of the third apparatus, the first LED light source provides full-area illumination, and wherein the laser-pumped second phosphor layer provides hot-spot illumination, and the light-source assembly further includes: a digital micromirror device (DMD) operatively coupled to receive light from the full-area illumination and the hot-spot illumination, wherein the DMD includes a plurality of micromirrors, wherein each of the plurality of micromirrors of the DMD is configured to selectively reflect light in one of a plurality of directions; and projection optics operatively coupled to receive light selectively reflected by the DMD and configured to project the received light as a beam having a shaped illumination intensity pattern.
In some embodiments of the third apparatus, the second phosphor layer is fused directly to the first phosphor layer.
Some embodiments of the third apparatus further include one or more heat-conducting structures coupled to both the heatsink and the second phosphor layer such that the one or more heat-conducting structures provide a heat-conduction path from the second phosphor layer to the heatsink, wherein the one or more heat-conducting structures are separated by an offset distance from sides of the first phosphor layer, and wherein the one or more heat-conducting structures are sized such that the second phosphor layer is separated from the first phosphor layer by a gap.
In some embodiments of the third apparatus, the second phosphor layer is fused directly to a first portion of the first phosphor layer.
In some embodiments of the third apparatus, the first phosphor layer has a first area, wherein the second phosphor layer has a second area, wherein the second area is smaller than the first area, and wherein the second phosphor layer is fused directly to a first portion of the first phosphor layer.
Some embodiments of the third apparatus further include a heat-conductive wall coupled to the heatsink, wherein the heat-conductive wall surrounds a perimeter of the first LED light source and the first phosphor layer, wherein the heat-conductive wall is separated from the perimeter of the first LED light source and the first phosphor layer by a gap; and a transparent heatsink window, wherein the transparent heatsink window is coupled to the heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer is conducted to the heatsink through the transparent heatsink window.
Some embodiments of the third apparatus further include a heat-conductive wall coupled to the heatsink, wherein the heat-conductive wall surrounds a perimeter of the first LED light source and the first phosphor layer, wherein the heat-conductive wall is separated from the perimeter of the first LED light source and the first phosphor layer by a gap; and a transparent heatsink window, wherein the transparent heatsink window is coupled to the heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer is conducted to the heatsink through the transparent heatsink window, wherein the transparent heatsink window separates the first phosphor layer from the second phosphor layer, wherein the first phosphor layer has a first area, wherein the second phosphor layer has a second area, and wherein the second area is smaller than the first area.
Some embodiments of the third apparatus further include a heat-conductive wall coupled to the heatsink, wherein the heat-conductive wall surrounds a perimeter of the first LED light source and the first phosphor layer, wherein the heat-conductive wall is separated from the perimeter of the first LED light source and the first phosphor layer by a gap; and a transparent heatsink window, wherein the transparent heatsink window is coupled to the heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer is conducted to the heatsink through the transparent heatsink window, wherein the transparent heatsink window is made of a material that includes aluminum oxynitride (AlON). In other embodiments, the transparent heatsink window is made of a material that includes diamond, sapphire and/or glass.
Some embodiments of the third apparatus further include a first heat-conductive wall coupled to the heatsink, wherein the first heat-conductive wall is separated by an offset distance from a first side of the first phosphor layer; and a cantilevered heatsink platform coupled to both the first heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer flows through the cantilevered heatsink platform and the first heat-conductive wall to the heatsink, wherein the cantilevered heatsink platform is suspended and separated above the first phosphor layer.
Some embodiments of the third apparatus further include a first heat-conductive wall coupled to the heatsink, wherein the first heat-conductive wall is separated by an offset distance from a first side of the first phosphor layer; and a cantilevered heatsink platform coupled to both the first heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer flows through the cantilevered heatsink platform and the first heat-conductive wall to the heatsink, wherein the cantilevered heatsink platform is suspended and separated above the first phosphor layer, wherein the first phosphor layer has a first area, wherein the second phosphor layer has a second area, and wherein the second area is smaller than the first area.
Some embodiments of the third apparatus further include a first heat-conductive wall coupled to the heatsink, wherein the first heat-conductive wall is separated by an offset distance from a first side of the first phosphor layer; and a cantilevered transparent heatsink coupled to both the first heat-conductive wall and the second phosphor layer such that heat from the second phosphor layer flows through the cantilevered transparent heatsink and the first heat-conductive wall to the heatsink, wherein the cantilevered transparent heatsink is suspended and separated above the first phosphor layer, wherein the first phosphor layer has a first area, wherein the second phosphor layer has a second area, and wherein the second area is smaller than the first area.
In some embodiments of the third apparatus, the first LED light source is one of a plurality of LED light sources, wherein each respective LED light source of the plurality of LED light sources includes a corresponding first phosphor layer affixed to the respective LED light source, wherein the second phosphor layer includes a reflective phosphor plate fused directly to at least a first one of the plurality of LED light sources.
In some embodiments of the third apparatus, the first LED light source is one of a plurality of LED light sources, wherein each respective LED light source of the plurality of LED light sources includes a corresponding first phosphor layer affixed to the respective LED light source, wherein the second phosphor layer is a reflective phosphor plate fused directly to at least a first one of the plurality of LED light sources, the light-source assembly further including: one or more lasers configured to optically pump the reflective phosphor plate, wherein the one or more lasers are supplied by an electric current; and a safety circuit integrated into the reflective phosphor plate and operatively coupled to the one or more lasers, wherein the safety circuit is configured to interrupt the electric current supplied to the one or more lasers when the reflective phosphor plate is broken.
In some embodiments, the present invention provides a fourth apparatus (such as illustrated in
Some embodiments of the fourth apparatus further include a controller operatively coupled to the DMD; a first light dump; and a second light dump, wherein the controller controls reflection directions of the plurality of micromirrors of the DMD such that light from the first light source is reflected to either the projection optics or the first light dump, and light from the second light source is reflected to either the projection optics or the second light dump.
Some embodiments of the fourth apparatus further include a vehicle, wherein the hybrid light source is mounted to the vehicle and controlled to provide smart headlight functions.
Some embodiments of the fourth apparatus further include a concave reflector, wherein the first light source of full-area illumination is projected onto the DMD by reflection from the concave reflector, and wherein the second light source of hot-spot illumination is projected onto the DMD through an aperture in the concave reflector.
In some embodiments of the fourth apparatus, the first light source of full-area illumination further includes: a light-emitting diode (LED) assembly; a lens operably coupled to receive light from the light-emitting diode (LED) assembly; a flat reflector operably coupled to receive light focused by the lens; and a concave reflector operably coupled to receive light reflected by the flat reflector, wherein light from the first light source of full-area illumination is projected onto the DMD by reflection from the concave reflector, and wherein the second light source of hot-spot illumination is projected onto the DMD through an aperture in the concave reflector.
In some embodiments of the fourth apparatus, the second light source of hot-spot illumination further includes: a phosphor plate; a blue-light laser that generates a blue-light laser beam that is focused onto the phosphor plate, wherein a portion of the blue-light laser beam is wavelength converted to yellow light; and collimating optics operably coupled to receive the wavelength-converted yellow light and an unconverted portion of the blue-light laser beam and configured to output collimated light as the beam of hot-spot illumination.
In some embodiments of the fourth apparatus, the second light source of hot-spot illumination further includes: a phosphor plate; a focusing lens; a blue-light laser that generates a blue-light laser beam that is focused by the focusing lens onto the phosphor plate, wherein a first portion of the blue-light laser beam is wavelength converted to yellow light and a second portion of the blue-light laser beam is unconverted and transmitted through the phosphor plate; and collimating optics operably coupled to receive the wavelength-converted yellow light and the unconverted portion of the blue-light laser beam and configured to output collimated light as the beam of hot-spot illumination.
In some embodiments, the present invention provides a fifth apparatus (such as illustrated in
Some embodiments of the fifth apparatus further include: a collimating optics structure configured to receive light from the phosphor structure and to collimate the light from the phosphor structure into a collimated beam having a collimated beam axis and a collimated beam direction; a reflector filter configured to selectively reflect at least light of the primary laser-light wavelength and positioned to reflect the laser light along the collimated beam axis in a direction opposite the collimated beam direction through the collimating lens structure toward a center of the phosphor structure. Some such embodiments further include a coupling lens structure configured to receive light from the phosphor structure and to collimate the light from the phosphor structure into a collimated beam having a collimated beam axis and a collimated beam direction; and a digital micromirror device (DMD) located and configured to reflect light from the collimated beam. Some such embodiments further include a projection lens assembly; and a total-internal-reflection (TIR) prism configured to receive the collimated beam and direct a resulting beam onto the DMD and to receive light reflected from the DMD and direct a resulting beam toward the projection lens assembly.
Some embodiments of the fifth apparatus further include a vehicle, wherein the hybrid light source is mounted to the vehicle and controlled to provide smart headlight functions.
Some embodiments of the fifth apparatus further include an enclosure window, wherein the heatsink forms a hollow enclosure that has the enclosure window sealed to a light-exit end of the hollow enclosure, and wherein the blue LED and the laser are mounted substantially inside of the hollow enclosure.
In some embodiments, the present invention provides a sixth apparatus (such as illustrated in
In some embodiments, the present invention provides a seventh apparatus (such as illustrated in
Some embodiments of the seventh apparatus further include a laser arranged to emit laser light that has a blue laser-light wavelength into the second phosphor structure through the second face of the second phosphor structure. Some such embodiments further include a safety circuit that automatically turns the laser off if the second phosphor structure breaks. In some such embodiments, the second phosphor structure is a crystal phosphor plate and wherein the safety circuit includes an electrically conductive trace on the crystal phosphor plate.
It is to be understood that the above description is intended to be illustrative, and not restrictive. Although numerous characteristics and advantages of various embodiments as described herein have been set forth in the foregoing description, together with details of the structure and function of various embodiments, many other embodiments and changes to details will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should be, therefore, determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein,” respectively. Moreover, the terms “first,” “second,” and “third,” etc., are used merely as labels, and are not intended to impose numerical requirements on their objects.
This application claims priority benefit, including under 35 U.S.C. § 119(e), of U.S. Provisional Patent Application 62/862,549 titled “ENHANCEMENT OF LED INTENSITY PROFILE USING LASER EXCITATION,” filed Jun. 17, 2019, by Kenneth Li; U.S. Provisional Patent Application 62/874,943 titled “ENHANCEMENT OF LED INTENSITY PROFILE USING LASER EXCITATION,” filed Jul. 16, 2019, by Kenneth Li; U.S. Provisional Patent Application 62/938,863 titled “DUAL LIGHT SOURCE FOR SMART HEADLIGHT APPLICATIONS,” filed Nov. 21, 2019, by Y. P. Chang et al.; and U.S. Provisional Patent Application 62/954,337 titled “HYBRID LED/LASER LIGHT SOURCE FOR SMART HEADLIGHT APPLICATIONS,” filed Dec. 27, 2019, by Kenneth Li; each of which is incorporated herein by reference in its entirety. This application is related to: P.C.T. Patent Application No. PCT/US2020/034447, filed May 24, 2020 by Y. P. Chang et al., titled “LiDAR INTEGRATED WITH SMART HEADLIGHT AND METHOD,” U.S. Provisional Patent Application No. 62/853,538, filed May 28, 2019 by Y. P. Chang et al., titled “LIDAR Integrated With Smart Headlight Using a Single DMD,” U.S. Provisional Patent Application No. 62/857,662, filed Jun. 5, 2019 by Chun-Nien Liu et al., titled “Scheme of LIDAR-Embedded Smart Laser Headlight for Autonomous Driving,” and U.S. Provisional Patent Application No. 62/950,080, filed Dec. 18, 2019 by Kenneth Li, titled “Integrated LIDAR and Smart Headlight using a Single MEMS Mirror,” PCT Patent Application PCT/US2019/037231 titled “ILLUMINATION SYSTEM WITH HIGH INTENSITY OUTPUT MECHANISM AND METHOD OF OPERATION THEREOF,” filed Jun. 14, 2019, by Y. P. Chang et al. (published Jan. 16, 2020 as WO 2020/013952); U.S. patent application Ser. No. 16/509,085 titled “ILLUMINATION SYSTEM WITH CRYSTAL PHOSPHOR MECHANISM AND METHOD OF OPERATION THEREOF,” filed Jul. 11, 2019, by Y. P. Chang et al. (published Jan. 23, 2020 as US 2020/0026169); U.S. patent application Ser. No. 16/509,196 titled “ILLUMINATION SYSTEM WITH HIGH INTENSITY PROJECTION MECHANISM AND METHOD OF OPERATION THEREOF,” filed Jul. 11, 2019, by Y. P. Chang et al. (published Jan. 23, 2020 as US 2020/0026170); U.S. Provisional Patent Application 62/837,077 titled “LASER EXCITED CRYSTAL PHOSPHOR SPHERE LIGHT SOURCE,” filed Apr. 22, 2019, by Kenneth Li et al.; U.S. Provisional Patent Application 62/853,538 titled “LIDAR INTEGRATED WITH SMART HEADLIGHT USING A SINGLE DMD,” filed May 28, 2019, by Y. P. Chang et al.; U.S. Provisional Patent Application 62/856,518 titled “VERTICAL CAVITY SURFACE EMITTING LASER USING DICHROIC REFLECTORS,” filed Jul. 8, 2019, by Kenneth Li et al.; U.S. Provisional Patent Application 62/871,498 titled “LASER-EXCITED PHOSPHOR LIGHT SOURCE AND METHOD WITH LIGHT RECYCLING,” filed Jul. 8, 2019, by Kenneth Li; U.S. Provisional Patent Application 62/857,662 titled “SCHEME OF LIDAR-EMBEDDED SMART LASER HEADLIGHT FOR AUTONOMOUS DRIVING,” filed Jun. 5, 2019, by Chun-Nien Liu et al.; U.S. Provisional Patent Application 62/873,171 titled “SPECKLE REDUCTION USING MOVING MIRRORS AND RETRO-REFLECTORS,” filed Jul. 11, 2019, by Kenneth Li; U.S. Provisional Patent Application 62/881,927 titled “SYSTEM AND METHOD TO INCREASE BRIGHTNESS OF DIFFUSED LIGHT WITH FOCUSED RECYCLING,” filed Aug. 1, 2019, by Kenneth Li; U.S. Provisional Patent Application 62/895,367 titled “INCREASED BRIGHTNESS OF DIFFUSED LIGHT WITH FOCUSED RECYCLING,” filed Sep. 3, 2019, by Kenneth Li; U.S. Provisional Patent Application 62/903,620 titled “RGB LASER LIGHT SOURCE FOR PROJECTION DISPLAYS,” filed Sep. 20, 2019, by Lion Wang et al.; and PCT Patent Application No. PCT/US2020/035492, filed Jun. 1, 2020 by Kenneth Li et al., titled “VERTICAL-CAVITY SURFACE-EMITTING LASER USING DICHROIC REFLECTORS”; each of which is incorporated herein by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US20/37669 | 6/14/2020 | WO |
Number | Date | Country | |
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62862549 | Jun 2019 | US | |
62874943 | Jul 2019 | US | |
62938863 | Nov 2019 | US | |
62954337 | Dec 2019 | US |