Light emitting devices with phosphor wavelength conversion and methods of fabrication thereof

This application is filed in US Patent Application No. 11 / 906,545 (agent reference number ITMX-00226US0), entitled LIGHT EMITTING DEVICES WITH PHOSPHOR WAVELENGTH CONVERSION AND METHODS OF FABRICATION THE REOF, submitted by James Caruso et al. On October 1, 2007. Claim priority.

Background of the invention Field of invention The present invention relates to a method and an apparatus for manufacturing a light emitting device having a phosphor wavelength conversion. More specifically, the present invention presents a light emitting diode (LED) capable of operating to emit light in the first wavelength range and a phosphor material that converts at least a portion of the light into light in the second wavelength range. It is related to a light emitting device of a method including and.

Description of related technology White light emitting diodes (LEDs) are known in the art and are a relatively recent technological innovation. It was not until the development of LEDs that emit light in the blue / ultraviolet part of the electromagnetic spectrum that it became practical to develop a white light source based on LEDs. As an example, as taught in US Pat. No. 5,998,925, a white photoluminescent LED (white LED) absorbs some of the radiation emitted by the LED and re-emits radiation of a different color (wavelength). Includes one or more phosphor materials, i.e. photoluminescent materials. Usually, the LED chip or die produces blue light, the phosphor absorbs a percentage of the blue light and re-emits a combination of yellow light or green and red light, green and yellow light or yellow and red light. Some of the blue light produced by the LEDs that is not absorbed by the phosphor, in combination with the light emitted by the phosphor, provides light that is visible to the human eye as an almost white color.

As is known, the correlated color temperature (CCT) of a white light source is determined by comparing its hue with a theoretically heated blackbody radiator. The CCT is indicated by Kelvin (K) and matches the temperature of a blackbody radiator that emits white light of the same hue as the light source. The CCT of a white LED is generally determined by the fluorophore composition and the amount of fluorophore incorporated into the LED.

White LEDs are often manufactured by mounting the LED chip in a metal or ceramic cup (housing) using an adhesive and then bonding the lead wire to the chip. To increase the efficiency of the device, the cup often has a reflective inner surface that reflects light out of the device. Usually, the fluorophore material in powder form is mixed with the silicone adhesive, after which the fluorophore mixture is placed on top of the LED chip. A problem in the manufacture of white LEDs is the variation in CCT and hue of color between LEDs that are nominally assumed to be the same. Especially in the white color range, this problem is exacerbated by the fact that the human eye is extremely sensitive to subtle changes in hue of color.

As mentioned earlier, to alleviate the problem of color variation in LEDs with phosphor wavelength conversion, especially white LEDs, LEDs are a "bin out" or "binning" system after production. Is categorized using. In binning, each LED is operated and the actual color of its emitted light is measured. The LEDs are then categorized or binned according to the actual color of the light produced by the device, without being based on the target CCT at creation. FIG. 1 is a CIE (International Commission on Illumination) 1931 chromaticity diagram of a cold white (CW) LED displaying four areas or color bins of a color space. More commonly, nine or more bins are used to classify white LEDs. Often, only two of the nine bins are acceptable for the intended use, and as a result, as challenges arise for the supply chain of white LED suppliers and consumers, the drawbacks of binning increase production. Cost and low yield rate.

U.S. Pat. No. 6,623,142 teaches that the spectral characteristics of an LED can be adjusted by placing a filter in the LED light emission path. The filter has a filter pattern that varies at least one color and intensity of light and is generated based on a shift value that matches the deviation of at least one color and intensity of emitted light from the reference. The filter can be printed on the LED lens or on a cap that is later attached to the LED using inkjet printing or other printing methods. The particular ink color selected for the filter depends on the deviation of the emitted light of each LED from the indicated tolerance. Filters are stated to provide a high degree of color and intensity uniformity without the need for labor and cost intensive binning. The drawback of filtering is that it is based on absorption to remove spectral components from the emission spectrum, resulting in reduced LED efficiency. Also, in the absence of spectral components, filtering cannot be used to correct spectral emissions, in other words, it is not possible to "add" spectral wavelengths to white LED emissions with this technique.

Variations in the hue of the emitted light color in LEDs with conventional phosphor wavelength conversion are believed to be the result of variations in the volume, composition, and position of the phosphor material on the LED chip. However, we have recognized that the variation in hue of colors may be further dependent on factors including: Variations in the shape and location of bonding wires that can affect the wetting of the phosphor Adhesive bleed out that can affect the wetting of the phosphor Variation in the emission direction of the LED chip Variation in reflector characteristics Variation of phosphor / silicone mixture or deterioration over time -Wavelength emission distribution of LED chips. It is believed that all of these factors can affect the hue of the color of the light produced by a light emitting device that includes phosphor wavelength conversion.

Outline of the invention The present invention, at least in part, stems from efforts to address the issue of LED color hue and / or CCT variability, including phosphor wavelength conversion, and reduce or eliminate the need for binning.

In an embodiment of the invention, a preselected amount of one or more phosphor materials is deposited on the light emitting surface of a light emitting diode; the light emitting diode is operated and the color of the light emitted by the device is measured; Aimed at depositing (adding) and / or removing (reducing) the fluorophore material to achieve the desired target color (target CIExy).

According to the present invention, a light emitting device having a specific target color (CIExy) of emitted light, at least one light emitting diode (LED) capable of operating to emit light in a first wavelength range, and at least. A device comprising at least one phosphor material that converts a portion of the light into light in a second wavelength range, and the light emitted by the device comprising a combination of light in the first and second wavelength ranges. How to make: a) The step of depositing a preselected amount of at least one fluorophore material on the light emitting surface of at least one LED; b) The process of operating at least one LED; c) The process of measuring the color of the light emitted by the device; d) The process of comparing the measured color to a particular target color; and e) The step of depositing and / or removing an amount of fluorophore material to achieve substantially a particular target color, depending on the comparison. Methods are provided, including.

To ensure the deposition of additional fluorophore material to achieve a particular target color (CIExy), this method also requires a ratio of light in the second wavelength range to be higher than that required for a particular target color. A step of selecting a preselected amount can be included to ensure that it is also low. Alternatively, the method can include selecting a preselected amount to ensure that the proportion of light in the second wavelength range is higher than in a particular target color. This arrangement ensures the removal of the fluorophore material to achieve a particular target color.

Preferably, the amount of fluorophore material deposited and / or removed is selected using a look-up table.

The method involves operating at least one light emitting diode more times and the light emitted by the device to verify that the color of the light emitted by the device substantially matches a particular target color. A step of measuring the color of the light emitting diode can be further included. Preferably, this information is used to update the look-up table when measuring color over a further number of times. Steps b) ~ e) of the method many times required to achieve a particular target color or to achieve a color within a predefined limitation (in other words, the range of CIE xy coordinates). Can be repeated.

Fluorescent material can be removed by melting, slicing, milling, polishing, drilling, routing, buffing or grinding. Alternatively, the fluorophore can be removed by wiping before the adhesive material solidifies.

To increase the intensity of the light emitted by the device, the device can each include at least one phosphor material and can include a plurality of light emitting diodes, usually arranged. When manufacturing such a device, this method is: a) The step of depositing a preselected amount of at least one fluorophore material on the light emitting surface of each LED; b) The process of operating all LEDs; c) The process of measuring the color of the light emitted by the device; d) The process of comparing the measured color to a particular target color; and e) The step of depositing and / or removing a fixed (unit) amount of fluorophore material for a number of light emitting diodes selected to achieve substantially a particular target color, depending on the comparison. including. As a specific effect of such a method, only a fixed amount of fluorophore needs to be deposited and / or removed, which can simplify the method.

The present invention is particularly suitable for the manufacture of white light emitting devices at a particular correlated color temperature (CCT). Often, such devices include two or more different fluorophore materials, each emitting light in a different wavelength range. According to a further aspect of the invention, a light emitting device having a particular target color (CIExy) of emitted light, a light emitting diode capable of operating to emit light in a first wavelength range, and at least one of the light. The light emitted by the device contains at least the first and second phosphor materials that separately convert the parts into light in the second and third wavelength ranges, and the light emitted by the device is in the first, second and third wavelength ranges. A method of manufacturing devices that include light combined with: a) The step of depositing a preselected amount of the first and second phosphor materials on the light emitting surface of the light emitting diode; b) The process of operating the light emitting diode; c) The process of measuring the color of the light emitted by the device; d) The process of comparing the measured color to a particular target color; and e) The step of depositing and / or removing the amounts of the first and second phosphor materials selected to achieve substantially a particular target color, depending on the comparison. Methods are provided, including.

Like the method according to the first embodiment of the present invention, the method ensures that the proportion of light in the second and third wavelength ranges is lower than in a particular target color. A step of selecting a preselected amount can be further included. Alternatively, the method further comprises selecting a preselected amount of phosphor material to ensure that the proportion of light in the second and third wavelength ranges is higher than in a particular target color. Can include. Preferably, the amount of fluorophore material deposited and / or removed is selected using a look-up table. When the light emitting device comprises a plurality of light emitting diodes including at least the first and second phosphor materials, the method, according to comparison, is a number of light emitting diodes selected to achieve substantially a particular target color. Includes the step of depositing and / or removing a fixed amount of the fluorophore material from.

According to still further aspects of the invention, a light emitting device having a particular target color of emitted light, a light emitting diode capable of operating to emit light in a first wavelength range, and at least a portion of the light. For manufacturing a device comprising at least one phosphor material that converts light into light in a second wavelength range, wherein the light emitted by the device comprises a combination of light in the first and second wavelength ranges. It's a device: Dispenser for depositing at least one phosphor material in a preselected amount on the light emitting surface of a light emitting diode; A controller that can operate to operate a light emitting diode; and A light measuring means for measuring the color of the light emitted by the device; The controller can be operated to compare the measured color with a specific target color, and depending on the comparison, deposit a further selected amount of phosphor material to achieve a substantially specific target color. There is a device provided.

In an alternative embodiment, a device for manufacturing a light emitting device having a specific target color of emitted light is: A dispenser capable of operating to deposit at least one phosphor material in a preselected amount on the light emitting surface of a light emitting diode; A controller that can operate to operate a light emitting diode; Light measuring means for measuring the color of light emitted by the device; and Fluorescent remover capable of acting to remove an amount of fluorophore material to achieve a particular target color Including, the controller can operate to compare the measured color with a specific target color and, depending on the comparison, select the amount of phosphor material removed to achieve a substantially specific target color. is there.

Advantageously, the device may further include a look-up table for selecting the amount of additional fluorophore material to be deposited and / or removed.

In one arrangement, the dispenser includes a plunger-type dispenser head capable of applying a nanoliter volume of fluorescent material.

Advantageously, the fluorophore removal means comprises a laser capable of operating to melt a selected amount of fluorophore material.

When the light emitting device contains multiple light emitting diodes including at least one phosphor material, a fixed amount of phosphor is compared to a number of light emitting diodes selected to achieve substantially a particular target color, according to comparison. The controller can be made operational to deposit material. Alternatively, the controller can operate to remove a fixed amount of fluorophore material from a number of light emitting diodes selected to achieve substantially a particular target color, depending on the comparison.

The present invention is particularly suitable for the manufacture of light emitting devices comprising two fluorophore materials, such as white light emitting devices. According to still further aspects of the invention, at least one light emitting diode having a particular target color of emitted light and capable of operating to emit light in the first wavelength range, and at least one of the light. The light emitted by the device contains the first, second and third wavelength ranges, including the first and second phosphor materials that separately convert the parts into light in the second and third wavelength ranges. A device for manufacturing devices, including combined light: A first dispenser for depositing a mixture of preselected amounts of first and second phosphor materials on the light emitting surface of at least one light emitting diode; Second dispenser for depositing the first fluorophore material; A third dispenser for depositing a second fluorophore material; A controller capable of operating at least one light emitting diode; A light measuring means for measuring the color of the light emitted by the device; Including, the measured color is compared with a specific target color, and depending on the comparison, the second and third dispensers are used and the amount of the first and selected amounts to achieve substantially the specific target color. An apparatus is provided in which the controller can operate to deposit a second phosphor material.

Here, for a better understanding of the present invention, embodiments of the present invention will be described here, with reference to the accompanying drawings, for example only:<figref num="1">FIG. 1 is a CIExy1931 chromaticity diagram showing a "bin out" of a cold white (CW) light emitting diode as described above;</figref><figref num="2A">FIG. 2A is a schematic diagram of the steps of the method of the invention for manufacturing a white light emitting device that includes phosphor wavelength conversion;</figref><figref num="2B">FIG. 2B is a schematic diagram of the steps of the method of the invention for manufacturing a white light emitting device that includes phosphor wavelength conversion;</figref><figref num="2C">FIG. 2C is a schematic diagram of the steps of the method of the invention for manufacturing a white light emitting device that includes phosphor wavelength conversion;</figref><figref num="2D">FIG. 2D is a schematic diagram of the steps of the method of the invention for manufacturing a white light emitting device that includes phosphor wavelength conversion;</figref><figref num="2E">FIG. 2E is a schematic diagram of the steps of the method of the invention for manufacturing a white light emitting device that includes phosphor wavelength conversion;</figref><figref num="2F">FIG. 2F is a schematic diagram of the steps of the method of the invention for manufacturing white light emitting devices including phosphor wavelength conversion;</figref><figref num="3">FIG. 3 is a CIExy1931 chromaticity diagram showing the method of color correction of the method of FIG. 2;</figref><figref num="4A">FIG. 4A is a schematic diagram of a process of a method according to a further embodiment of the present invention for manufacturing a color emitting device comprising phosphor wavelength conversion.</figref><figref num="4B">FIG. 4B is a schematic diagram of the steps of a method according to a further embodiment of the invention for manufacturing a color emitting device comprising phosphor wavelength conversion.</figref><figref num="4C">FIG. 4C is a schematic diagram of the process of a method according to a further embodiment of the invention for manufacturing a color emitting device comprising phosphor wavelength conversion.</figref><figref num="4D">FIG. 4D is a schematic diagram of the steps of a method according to a further embodiment of the invention for manufacturing a color emitting device comprising phosphor wavelength conversion.</figref><figref num="4E">FIG. 4E is a schematic diagram of a process of a method according to a further embodiment of the present invention for manufacturing a color emitting device comprising phosphor wavelength conversion.</figref><figref num="5">FIG. 5 is a CIE chromaticity diagram showing the color correction method of the method of FIG.</figref>

Method 1 A method according to the first embodiment of the present invention will be described with respect to the manufacture of a white light emitting device having a specific color temperature and hue. In the present patent specification, a color is converted into a chromaticity value and defined, and a specific color is defined as having a specific CIE xy chromaticity coordinate. However, it is recognized that other color defining systems can be used for the methods of the invention.

The white light device 10 produces an LED chip 20, eg, excitation radiation (light) in the first wavelength range, typically blue light with a wavelength of 400-465 nm, InGaN / GaN (indium gallium nitride / gallium nitride). Includes LED chips. Device 10 uses two different light emitting phosphor (photoluminescence or wavelength conversion) materials that separately convert at least a portion of the light emitted by the chip into light of different colors, eg, yellow and green light, for example. Is further included. The blue light emitted by the chip is combined with the yellow and green light emitted by the phosphor to give an emitted light that appears white in color and has a specific color temperature and / or hue. The LED chip 20 is actually mounted in a ceramic or metal cup, but the attached figure does not depict such packaging.

With reference to FIGS. 2 (A) to 2 (F), the process of the method of the present invention for manufacturing a white light emitting device 10 having a specific color temperature (hue of color) is shown. The hue of a specific color, which is hereinafter referred to as the target color in the present specification, is displayed as a point 200 on the CIE chromaticity diagram of FIG. 3, and the chromaticity coordinate CIE (x).₁, y₁). The method of the present invention is preferably embodied in the form of a fully automated production line.

Step 1-Figure 2 (A) and (B): Fluorescent material in powder form with a transparent adhesive (bonding) material in a preselected ratio, eg, a quick-drying thermosetting transparent silicone. Mix. An example of a suitable silicone material is GE's Silicone RTV615. The charge weight ratio of the fluorophore mixture to silicone depends on the required target color of the device and is in the range of 5-50%. In the first step, a preselected amount of the yellow and green light emitting phosphor mixture 30 is deposited on the light emitting surface of the LED chip 20. A dispenser 40, eg, a nanoliter-sized plunger-type dispenser head made by Asymtek, can be used to deposit a mixture of phosphor and adhesive. The ratio of yellow and green light is the target color CIE (x)₁, y₁) Is selected in a preselected amount (volume) of the fluorophore mixture to ensure lower. A reduced proportion of green light generally results in a lower CIE (y), and a reduced proportion of yellow light generally results in a lower CIE (x). Be recognized.

Step 2-Figure 2 (C): Turn on the LED chip 20 and measure the color of the light 50 emitted by the device 20 using a photometer (colorimeter or spectrometer) 60. The color is preferably measured by converting it into the chromaticity coordinates CIEx, y. The hue of the measured color, displayed as point 220 in the chromaticity diagram of Figure 3, is the target color 200 CIE (x).₁, y₁) And calculate the amount of additional yellow and green fluorescent material needed to achieve the target color. In FIG. 3, the addition of the yellow phosphor material causes the color to move in the direction substantially matching the arrow 240, and the addition of the green phosphor causes the color to shift in the direction substantially matching the arrow 260. Is shown. (It is recognized that with the addition of the yellow fluorophore, the color moves much less in the direction of arrow 260, and similarly, with the addition of the green fluorophore, the color moves less less in the direction of arrow 240. By using two different phosphor materials whose amounts can be controlled individually, the colors can be controlled substantially individually in the x and y directions of the chromaticity diagram. In a preferred device, a look-up table (typically referred to as a LUT, used herein) is used to determine the amount of additional fluorophore material to be deposited. The LUT can contain the following parameters: Goal CIE (x)₁, y₁), Actual CIE (x, y), amount of additional yellow fluorophore and amount of additional green fluorophore. A look-up table can be obtained by first manufacturing a library of devices with different amounts of phosphors and measuring the color of the emitted light. LUTs are preferably color values that are perceptually linear in a uniform color space, eg, for example, changes in the same amount of color values create approximately the same changes in visual importance. CIE1976 (L^*a^*b b^*) Based on the color space (CIELAB).

Step 3-Figures 2 (D) and (E): A selected amount of yellow 70 and green 80 fluorescent material calculated to achieve the target color is deposited on the LED chip 20. Each dispenser 90, 100 can be used to deposit the respective material in a selected volume and deposit the fluorophore material. Fluorescent dispensers 40, 90 and 100 preferably include nanoliter-sized plunger-type dispenser heads of multi-head dispensers, each of which allows the fluorescent material to be applied in the same place. Since the actual color of the device emission is already close to the target color, only a small additional amount of fluorophore needs to be deposited, using a fluorophore mixture with a lower fluorophore charge and depositing of the fluorophore It is preferable to achieve more precise control over the amount.

Step 4-Figure 2 (F): In some cases, the LED chip 20 is powered on twice, the color of the light emitted by the device 10 is measured, and the device sets the target color CIE (x).₁, y₁) Is emitted. It is not necessary to measure the color of the light emitted by the device twice, but a method of quality control checking can be provided. In addition, the measured colors can be used to update the look-up table to refine the system.

Since there may be variations in the spectral emission of the LED chip, this method measured the process of first turning on the power of the LED chip 20 and the step of measuring the color of the emitted light using a photometer 60. A step of selecting a preselected amount of the fluorescent mixture 30 to be deposited in step 1 based on color can be further included.

Although the method has been described for the manufacture of a single light emitting device, it is recognized that the method is particularly suitable and intended for mass production of light emitting devices. In one method, light emitting devices can be manufactured in lots by processing a large number of LED chips at once. First, a preselected amount of the phosphor mixture is deposited on each chip. After that, each LED chip is turned on and the color of the light emitted by the device is measured. For each device, calculate the amount of additional phosphor required to achieve the target color of emitted light. Finally, a selected amount of fluorophore material is deposited on each device. The production line can be embodied in the form of an automated conveyor where lots of LED chips pass between various stations.

So far, we have described this method of manufacturing a light emitting device, including a single LED chip with phosphor wavelength conversion. However, in many cases, light emitting devices based on high intensity LEDs, such as those intended for lighting applications, include multiple or array of LED chips. The methods of the present invention can be readily applied to the manufacture of such devices.

Here, the manufacture of a white light emitting device including 16 LED chips in a 4 × 4 array will be described, but this method can be applied to other LED arrays, for example, linear arrays with different numbers of LED chips. it can. A preselected amount of yellow and green light emitting fluorescent material is deposited on each LED chip in the array. Again, the ratio of yellow and green light is the target color CIE (x)₁, y₁) Is deliberately lower than required to achieve), the preselected amount of fluorophore material to be deposited first is selected. Steps 2 and 3 described above can be used to optimize the color of the light emitted by each LED chip in the array to the target color. However, the alternative method optimizes the final color of the light emitted by the device to the target color. The latter powers on all the LED chips in the array and measures the final color of the light emitted by all the LEDs in the array. Compare the measured color to the target color and calculate the amount of yellow and green phosphor material that needs to be deposited to achieve the target color. In the first arrangement, a selected amount of fluorophore material is deposited on each LED chip in the array by the method of step 4. The disadvantage of this method is that variable amounts of fluorophore material must be deposited to achieve the target color of different devices. The alternative method is to deposit only a set unit amount (volume) of fluorophore on one or more LED chips in the array. In an array containing 16 LED chips and two fluorophore materials, there can be 256 (16 x 16) color corrections for a given unit volume of fluorophore.

Method 2 In the second method, excess fluorophore material is deliberately deposited and then the fluorophore material is removed to achieve the target color. This method is more suitable for light emitting devices that contain only a single fluorophore material. The method of the present invention is described with respect to the manufacture of a color emitting device having a hue of a specific target color. The color emitting device 310 is an LED chip 320, eg, an InGaN / GaN (indium gallium nitride / gallium nitride) that produces excitation radiation in the first wavelength range, eg, blue light with a wavelength of 400-450 nm. ) Includes LED chips. The device further comprises a light emitting phosphor (photoluminescence or wavelength conversion) material that converts at least a portion of the light emitted by the chip into light of a different color, eg, green light, for example. The blue light emitted by the chip and the green light emitted by the phosphor combine to give a particular hue, eg, a turquoise-looking emitted light. The hue of a specific color, which is hereinafter referred to as the target color in the present specification, is displayed as a point 400 on the CIE chromaticity diagram of FIG. 5, and the chromaticity coordinate CIE (x).₂, y₂).

With reference to FIGS. 4A to 4E, the process of the method of the present invention for manufacturing a color emitting device of a target color is shown.

Step 1-Figures 4 (A) and 4 (B): The fluorophore material is mixed with a clear adhesive (bonding) material and a preselected amount of the fluorophore mixture 330 is deposited on the light emitting surface of the LED chip 320. .. As in the first method, a dispenser 340, for example a nanoliter size plunger head, can be used to deposit a mixture of phosphor and adhesive. However, unlike the first method, the ratio of light produced by the phosphor is the target color CIE (x).₂, y₂) Intentionally exceeds, in other words, the device selects a preselected amount of phosphor to be deposited to ensure that a higher proportion of green light is produced.

Step 2-Figure 4 (C): Power on the LED chip 320 and measure the color of the light 350 emitted by the device using a photometer (colorimeter or spectrometer) 360. Compare the measured color, displayed as point 420 in FIG. 5, with the target color 400 and calculate the amount of phosphor removed to achieve the target color. Referring to FIG. 5, the removal of the fluorophore material causes the color to move along line 460 in the direction of arrow 440. Line 460 connects the points on the CIE diagram that match the color of the light emitted by the LED chip (blue in this example) and the color of the light emitted by the phosphor (green in this example). In a preferred device, a LUT is used to determine the amount of fluorophore material removed. The LUT preferably contains the following parameters: Goal CIE (x)₂, y₂), The actual CIE (x, y) and the amount of phosphor removed.

Step 3-Figure 4 (D): A selected amount of phosphor material is removed from the surface of the LED chip 320 to achieve the target color. Preferably, a laser 370 is used to melt the surface of the fluorophore coating and remove the fluorophore material. Alternatively, the fluorophore can be removed by other methods, such as slicing, milling, polishing, drilling, routing, buffing, grinding or mechanical means including wiping before the adhesive material solidifies.

Step 4-Figure 4 (E): In some cases, again, the LED chip 320 is powered on, the color of the light emitted by the device 310 is measured, and the device sets the target color CIE (x).₂, y₂) Is emitted. As in the first method, the measured color can be used to update the LUT to refine the system or as a quality control check.

Since the spectral emission of the LED chip can vary, this method measured the process of first powering on the LED chip 320 and the process of measuring the color of the emitted light using a photometer 360. A step of selecting a preselected amount of the fluorescent mixture 330 to be deposited in step 1 based on color can be further included.

Like the first method, the method according to the second embodiment can be used for mass production of light emitting devices and production of devices including a plurality of LED chips. In the latter case, the fluorophore material can be selectively removed from one or more LED chips, optimizing the device for the final emitted light or optimizing the light output color of each LED.

As a special advantage of the method of the present invention, the need for binning can be eliminated. The method of the present invention comprises an inorganic fluorescent material, eg, for example, having a general composition of A.₃Si (OD)₅Or A₂Si (OD)₄Where Si is silicon, O is oxygen, A contains strontium (Sr), barium (Ba), magnesium (Mg) or calcium (Ca), D is chlorine (Cl), fluorine Intended for use in silicate-based phosphors containing (F), nitrogen (N) or sulfur (S). Examples of silicate-based phosphors are co-pending US patent applications 2006/0145123, 2006/028122, 2006/261309 of the present inventors, the respective contents of which are incorporated herein by reference. And disclosed in No. 2007/029526.

Europium (Eu) as taught in U.S. Patent Application No. 2006/0145123²⁺) Activated silicate-based green phosphor is a general formula (Sr, A)₁)_x(Si, A₂) (O, A₃)_{2 + x}:EU²⁺And here: A₁2+ cations, 1+ and 3+ cations, for example Mg, Ca, Ba, zinc (Zn), sodium (Na), lithium (Li), bismuth (Bi), yttrium (Y) or cerium ( At least one of the Ce) combinations; A₂Are 3+, 4+ or 5+ cations, eg boron (B), aluminum (Al), gallium (Ga), carbon (C), germanium (Ge), N or phosphorus (P); A₃Is a 1-, 2- or 3-anion, eg, F, Cl, bromine (Br), N or S, for example. The formula is A₁Cation replaces Sr; A₂The cation replaces Si and A₃Described to indicate that the anion replaces O. The value of x is an integer or non-integer from 2.5 to 3.5.

In U.S. Patent Application 2006/028122, Equation A₂SiO₄:EU²⁺Has D, where A is at least one of the divalent metals containing Sr, Ca, Ba, Mg, Zn or cadmium (Cd); D is F, Cl, Br, iodine (I), P , S and N-containing dopants, silicate-based yellow-green phosphors. Dopant D can be present in the fluorophore in an amount in the range of approximately 0.01-20 mol percent. The phosphor is (Sr_1-xyBa_xM_y) SiO₄:EU²⁺Can include F, where M comprises Ca, Mg, Zn or Cd.

In U.S. Patent Application No. 2006/261309, the crystal structure is (M1).₂SiO₄First phase, which is substantially the same as; and the crystal structure is (M2)₃SiO₅It has a second phase that is substantially the same as, here teaching a two-phase silicate-based phosphor in which M1 and M2 contain Sr, Ba, Mg, Ca or Zn, respectively. At least one phase is divalent europium (Eu)²⁺), And at least one of the phases contains a dopant D containing F, Cl, Br, S or N. It is believed that at least some dopant atoms are located at the oxygen atom lattice sites of the host silicate crystal.

In U.S. Patent Application No. 2007/029526, the formula (Sr_1-xM_x)_yEU₂SiO₅Where M is at least one of the divalent metals containing Ba, Mg, Ca or Zn; 0 &lt;x &lt;0.5; 2.6 &lt;y &lt;3.3; and 0.001 &lt;z &lt;0.5, silicate The orange phosphor is disclosed. The phosphor is configured to emit visible light with a peak emission wavelength higher than approximately 565 nm.

Fluorescent materials are aluminate-based materials as taught in our co-pending U.S. Patent Applications 2006/0158090 and 2006/0027786, each of which is incorporated herein by reference. Can also be included.

In U.S. Patent Application 2006/0158090, Equation M_1-xEU_xAl_yO_{[1 + 3y / 2]}Where M is at least one of the divalent metals containing Ba, Sr, Ca, Mg, Mn, Zn, Cu, Cd, Sm and thulium (Tm), 0.1 &lt;x &lt;0.9 and 0.5 It teaches an aluminate-based green phosphor with y 12.

In U.S. Patent Application No. 2006/0027786, Equation (M)_1-xEU_x)_2-zMg₂Al_yO_{[1 + 3y / 2]}Here, an aluminate-based phosphor in which M is at least one of the divalent metals of Ba or Sr is disclosed. In one composition, the phosphor is configured to absorb radiation with wavelengths in the range of approximately 280 nm to 420 nm and emit visible light with wavelengths in the range of approximately 420 nm to 560 nm, and 0.05 &lt;x &lt;0.5. Or 0.2 &lt;x &lt;0.5; 3 y 12 and 0.8 z 1.2. The phosphor is further doped with a halogen dopant H, such as Cl, Br or I, to give it a general composition (M)._1-xEU_x)_2-zMg_zAl_yO_{[1 + 3y / 2]}Can be: H.

The fluorophore is not limited to the examples described herein, and any inorganic fluorophore material, including, for example, nitride and sulfate phosphor materials, oxynitrides and oxysulfate phosphors or garnet materials (YAG). It is recognized that can include.

Furthermore, it is recognized that the present invention is not limited to the particular embodiments described and can make variants within the scope of the present invention. As an example, in another embodiment of the invention, different light emitting phosphor materials can be used to adjust (modify) the device to a target color hue or CCT. In one embodiment, a preselected amount of a first fluorophore, eg, a yellow light emitting fluorophore, is deposited on a blue LED chip, eg, a cold white (CW) with a CCT of 6000-7000K. By creating a light emitting device that emits light, a warm white (WW) light emitting device with a target CCT (eg, 3000K) can be manufactured. The device is then powered on, the color of the emitted light is measured and compared to the target color (CCT). Then, in response to the comparison, a selected amount of a second fluorophore, eg, a green light emitting fluorophore, is deposited on the device and the emitted CCT is adjusted (modified) to the target CCT. Also, while the first method has been described for the manufacture of white light emitting devices, it is recognized that this method can be used to manufacture light emitting devices of any color and / or hue of a specific color. ..

The fluorophore material can be deposited using any technique, eg, inkjet printing, spraying, etc., for example. As an example, it is envisioned that a halftone system is used to deposit the fluorophore material as a pattern containing an array of evenly spaced, non-overlapping areas (dots) of varying size. When using two different fluorophore materials, the dots alternate between the fluorophore materials and the relative size and / or spacing of the dots is used to control the relative amount of the two phosphors.

The phosphor can be mixed with other adhesive materials and in one embodiment it is envisioned that a UV curable material, such as a UV curable silicone material, will be used. Here, this UV curing method is advantageous when a system with a particularly high throughput is desired, as is most often the case.

The method can also include a combination of methods of the invention that selectively add and / or remove phosphor material to achieve a particular target color hue.