Patent Application
20150325759
1. Field of the Invention
This invention pertains generally to light emitters and the optical elements used therewith, and particularly to optical elements having an integrated indicator.
2. Description of the Related Art
Incandescent or filament-based lamps or bulbs are commonly used as light sources for both residential and commercial facilities. However, such lamps are highly inefficient light sources, with as much as 95% of the input energy lost, primarily in the form of heat or infrared energy. One common alternative to incandescent lamps, so-called compact fluorescent lamps (CFLs), are more effective at converting electricity into light but require the use of toxic materials which, along with its various compounds, can cause both chronic and acute poisoning and can lead to environmental pollution. One solution for improving the efficiency of lamps or bulbs is to use solid state devices such as light emitting diodes (LED or LEDs), rather than metal filaments, to produce light.
Light emitting diodes generally comprise one or more active layers of semiconductor material sandwiched between oppositely doped layers. When a bias is applied across the doped layers, holes and electrons are injected into the active layer where they recombine to generate light. Light is emitted from the active layer and from various surfaces of the LED.
In order to use an LED chip in a circuit or other like arrangement, it is known to enclose an LED chip in a package to provide environmental and/or mechanical protection, color selection, light focusing and the like. An LED package can also include electrical leads, contacts or traces for electrically connecting the LED package to an external circuit.
In a typical LED package 10 illustrated in
Packages and fixtures that emit a combination of different wavelengths of light, and particularly multicolor source packages and fixtures with chips emitting different wavelengths, often cast shadows with color separation and provide an output with poor color uniformity. For example, a package featuring blue and yellow sources may appear to have a blue tint when viewed head on and a yellow tint when viewed from the side. Thus, one challenge associated with multicolor light sources is good spatial color mixing over the entire range of viewing angles to achieve acceptable color spatial uniformity (“CSU”). An LED package with good CSU will emit light of relatively constant CCT across many viewing angles. One known approach to the problem of color mixing is to use a diffuser to scatter light from the various sources. Another known method is to reflect or bounce the light off of several surfaces before it is emitted.
Many different encapsulant shapes are possible. The encapsulant 12 is cylindrical. The encapsulant can be shaped for purposes including but not limited to maximizing efficiency and improving color mixing. For example, many traditional packages utilize a hemispheric encapsulant, which can minimize total internal reflection, to improve output efficiency.
Unlike incandescent lights which illuminate regardless of electrical polarity, LEDs will only light when forward-biased. If reverse-biased, very little current flows and no light is emitted. If a package and/or encapsulant is substantially symmetrical, such as the package 10 and encapsulant 12, LED packages can contain orientation indicators to ensure that they are correctly mounted such that the LED(s) will be forward-biased. Packages such as the package 10 must be mounted on a mount surface such that the LEDs therein will be forward-biased when operating.
Referring to
Some newer LED packages do not include an uncovered portion of a mount surface. This can help to minimize the overall package footprint. For example,
However, as described above, many modern packages include encapsulants which include wavelength conversion material such as phosphor. For example,
One solution to this problem is to include a polarity indicator on the bottom of the package. Referring back to
The need exists for reliable and cost-effective methods of indicating package polarity in certain types of packages, while at the same time avoiding the sacrifice or alteration of other package characteristics.
Briefly, and in general terms, the invention is directed toward polarity indicators in, on, or otherwise included with optical elements.
One embodiment of a light emitting device according to the present invention includes an optical element comprising an indicator.
One embodiment of an optical element according to the present invention is shaped to define an integrated indicator.
One method of forming an optical element according to the present invention can include providing a substantially symmetrical optical element and forming an integrated indicator such that the optical element is no longer substantially symmetrical.
One embodiment of an emitter wafer according to the present invention can include a plurality of emitter packages collectively having one or more common layers. The one or more common layers can include a top layer that is shaped to define an integrated indicator in each of the emitter packages.
These and other aspects and advantages of the invention will become apparent to those skilled in the art from the following detailed description and the accompanying drawings, which illustrate by way of example the features of the invention.
The present invention is directed toward indicators that can be included in encapsulants or other optical elements. Indicators can make determining the mounting orientation of the device easier for a technician or mounting mechanism while having little or no effect on device output. Indicators can be additive (e.g., a “bump”) or subtractive (e.g., a “hole”), and can be formed in many different ways. Indicators that are defined by the shape of an optical element, or integrated indicators, can be particularly useful when indicators would not be visible on a traditional indication surface, such as the top surface of a substrate.
Integrated indicators can take many different forms and can be included with many different types of optical elements. For example, an additive indicator can take the form of a bump on an optical element, whereas a subtractive indicator can take the form of a dip within the optical element. Indicators can be included with encapsulants and remote phosphor elements of any type or shape, as well as with many other types of optical elements.
Integrated indicators can be large enough to be visible to the human eye while minimizing any effect on the package or fixture output. For example, an indicator can have a diameter of about 200 μm to about 500 μm, or about 300 μm. Packages with encapsulants including integrated polarity indicators have been tested to have the same or about the same lumen output and a similar or negligibly different beam spread as equivalent packages without an indicator.
Integrated indicators can be included in traditional optical materials such as silicone. One method for forming silicone optical elements with an indicator is molding. Laser imprinting or ablation can be used with many different optical materials, including but not limited to glass. In one embodiment the laser can be pulsed while either the laser or a host wafer is moved, such that the laser deposits an indicator at the same spot of each package with each pulse. In another embodiment the laser can be continuously on while either the laser or host wafer is moved, depositing a line or trench indicator that is not along a line of symmetry, such as the x- or y-axis or a diagonal of a rectangle.
Indicators according to the present invention can communicate many different types of information to a technician or mounting mechanism. For instance, in some embodiments the indicator is used to communicate one or more pieces of information about that specific package. For instance, the location of an indicator can communicate the polarity of the package, the orientation in which the package is to be mounted, the location of one or more solder pads, and/or the primary emission direction of the package. “Location” as used herein can also include a direction communicated by an indicator. For example, an indicator can be in the center of an optical element, but can be shaped to indicate one side/corner of the package (e.g., shaped like an arrow). These above indicators can sometimes be referred to as “orientation indicators.” Embodiments other than these are possible.
In some embodiments, the indicator is used to communicate a characteristic of the package having to do with its type as opposed to a physical location or orientation, which can be referred to “type indicators.” For example, two different types of packages can often look the same to a technician or mounting mechanism, and/or can have the same footprint. The inclusion of a first type of indicator on one type of package and either no indicator or a second type of indicator on another type of package can differentiate the package types. These characteristics include but are not limited to type of chip(s) within the package, number of chips within the package, epitaxial characteristics, emission color, emission brightness, etc. In one embodiment, a type indicator is located such that the optical element is still symmetrical despite the inclusion of the indicator, since the optical element can still communicate the type of package despite being symmetrical, which may not be possible in orientation indicators. This can sometimes increase emission uniformity. Many different type characteristics can be communicated by indicators according to the present invention, and the above examples are in no way limiting.
Combination indicators are also possible. For example, in any of the below embodiments and in other embodiments of the present invention, one characteristic of an indicator can communicate type while another characteristic of the indicator can communicate orientation, polarity, or some other characteristic. In one embodiment, the shape of the indicator communicates the type of package while the location of the indicator communicates orientation, polarity, etc. In other embodiments, two different indicators are used, one as an orientation indicator and one as a type indicator. Many different embodiments and combinations are possible.
The present invention is described herein with reference to certain embodiments, but it is understood that the invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In particular, the present invention is described below in regards to certain LED packages having LED chips in different configurations, but it is understood that the present invention can be used for many other LED packages with other LED configurations. The LED packages can also have many different shapes beyond those described below, such as rectangular, and solder pads and attach pads can be arranged in many different ways. In other embodiments, the emission intensity of the different types of LED chips can be controlled to vary the overall LED package emission.
The present invention can be described herein with reference to conversion materials, wavelength conversion materials, remote phosphors, phosphors, phosphor layers and related terms. The use of these terms should not be construed as limiting. It is understood that the use of the term remote phosphors, phosphor or phosphor layers is meant to encompass and be equally applicable to all wavelength conversion materials.
The present invention can be described herein with reference to scatterers, scatters, scattering particles, diffusers, and related terms. The present invention can also be described herein with reference to reflectors, reflective particles, reflective surfaces, and related terms. The use of these terms should not be construed as limiting. It is understood that the use of these terms is meant to encompass and be equally applicable to all light scattering materials and/or reflective materials.
The embodiments below are described with reference to an LED or LEDs, but it is understood that this is meant to encompass LED chips, and these terms can be used interchangeably. These components can have different shapes and sizes beyond those shown, and one or different numbers of LEDs can be included. It is also understood that the embodiments described below utilize co-planar light sources, but it is understood that non co-planar light sources can also be used. It is also understood that an LED light source may be comprised of multiple LEDs that may have different emission wavelengths. As mentioned above, in some embodiments at least some of the LEDs can comprise blue emitting LEDs covered with a yellow phosphor along with red emitting LEDs, resulting in a white light emission from the LED package. In multiple LED packages, the LEDs can be serially interconnected or can be interconnected in different serial and parallel combinations.
It is also understood that when a feature or element such as a layer, region, encapsulant or submount may be referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. Furthermore, relative terms such as “inner”, “outer”, “upper”, “above”, “lower”, “beneath”, and “below”, and similar terms, may be used herein to describe a relationship of one layer or another region. It is understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. Further, many of the embodiments of the present invention are shown with a “top” primary emission surface. It is understood that any one or more surfaces, including but not limited to a top surface, can be (or can combine to form) a primary emission surface. For example, a package can be designed to have a primary emission out a side emission surface.
Although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.
Embodiments of the invention are described herein with reference to cross-sectional view illustrations that are schematic illustrations of embodiments of the invention. As such, the actual thickness of the layers can be different, and variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances are expected. Embodiments of the invention should not be construed as limited to the particular shapes of the regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. A region illustrated or described as square or rectangular will typically have rounded or curved features due to normal manufacturing tolerances. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region of a device and are not intended to limit the scope of the invention.
Many different phosphors can be used in encapsulants according to the present invention being particularly adapted to lamps emitting white light. Light sources used in embodiments of the present invention can be LED based with at least some, and in some embodiments all, of the LEDs emitting light in the blue wavelength spectrum. The phosphor layer can absorb some of the blue light and re-emit yellow. This allows the lamp to emit a white light combination of blue and yellow light. In some embodiments, the blue LED light can be converted by a yellow conversion material using a commercially available YAG:Ce phosphor, although a full range of broad yellow spectral emission is possible using conversion particles made of phosphors based on the (Gd,Y)3(Al,Ga)5O12:Ce system, such as the Y3Al5O12:Ce (YAG). Other yellow phosphors that can be used for creating white light when used with a blue emitting LED based emitter include but are not limited to:
Some arrangements according to the present invention can utilize multiple phosphors, such as two or more phosphors mixed in together or in separate sections. In some embodiments, each of the two phosphors can absorb the LED light and can re-emit different colors of light. In these embodiments, the colors from the two phosphor layers can be combined for higher CRI white of different white hue (warm white). This can include light from yellow phosphors above that can be combined with light from red phosphors. Different red phosphors can be used including:
Other phosphors can be used to create color emission by converting substantially all light to a particular color. For example, the following phosphors can be used to generate green light:
The following lists some additional suitable phosphors that can be used as conversion particles, although others can be used. Each exhibits excitation in the blue and/or UV emission spectrum, provides a desirable peak emission, has efficient light conversion, and has acceptable Stokes shift:
(Sr, Ca, Ba) (Al, Ga)2S4:Eu2+
Ba2(Mg, Zn) Si2O7:Eu2+
Gd0.46Sr0.31Al1.23OxF1.38:Eu2+0.06
(Ba1-x-ySrxCay) SiO4:Eu
Ba2SiO4:Eu2+
Lu3Al512 doped with Ce3+
(Ca, Sr, Ba) Si2O2N2 doped with Eu2+
CaSc2O4:Ce3+
(Sr, Ba) 2SiO4:Eu2+
Lu2O3:Eu3+
(Sr2-xLax) (Ce1-xEux) O4
Sr2Ce1-xEuxO4
Sr2-xEuxCeO4
SrTiO3:Pr3+, Ga3+
CaAlSiN3:Eu2+
Sr2Si5N8:Eu2+
Different sized phosphor particles can be used including but not limited to particles in the range of 10 nanometers (nm) to 30 micrometers (μm), or larger. Smaller particle sizes typically scatter and mix colors better than larger sized particles to provide a more uniform light. Larger particles are typically more efficient at converting light compared to smaller particles, but emit a less uniform light.
The converter can comprise one or multiple layers of different phosphor materials, with some multiple layer arrangements described in commonly assigned U.S. patent application Ser. No. 13/029,063 to Hussell et al. and entitled “High Efficiency LED Lamp With Remote Phosphor and Diffuser Configuration,” which is fully incorporated by reference herein in its entirety.
Different embodiments of packages according to the invention can also comprise different types and arrangements of scattering particles or scatterers. Some exemplary scattering particles include:
Other materials not listed may also be used. Various combinations of materials or combinations of different forms of the same material can also be used to achieve a particular scattering effect. For example, in one embodiment a first plurality of scattering particles includes alumina and a second plurality of scatting particles includes titanium dioxide. In other embodiments, more than two types of scattering particles are used. Scattering particles are discussed generally in the commonly assigned applications U.S. patent application Ser. No. 11/818,818 to Chakraborty et al. and entitled “Encapsulant with Scatterer to Tailor Spatial Emission Pattern and Color Uniformity in Light Emitting Diodes,” and U.S. patent application Ser. No. 11/895,573 to Chakraborty and entitled “Light Emitting Device Packages Using Light Scattering Particles of Different Size,” each of which is fully incorporated by reference herein in its entirety.
Embodiments of the present invention can include an indicator integrated into the encapsulant. These indicators can be, for example, orientation indicators, polarity indicators, type indicators, etc., which can indicate to a technician or machine any number of pieces of information about the package. It is understood that the terms “indicator,” “orientation indicator,” “polarity indicator,” “type indicator,” and other similar terms are used interchangeably herein unless otherwise noted, such as when specifically referring to an orientation, polarity, or package type, for example.
Indicators according to the present invention can communicate many different package characteristics. In one embodiment an indicator communicates the polarity of the package. In another embodiment the indicator communicates the mounting orientation of the package. In another embodiment the indicator communicates the location of one or more solder pads. In another embodiment the indicator communicates the primary emission direction of the package. In another embodiment the indicator communicates the number and/or type of chips within the package. In another embodiment the indicator communicates one or more emission characteristics of the package, such as emission color, brightness, and/or emission pattern. Any of the indicators described herein, including those described in relation to the below embodiments, can serve to communicate any type of information about the package which the user desires it to communicate. Further, any characteristic of the indicator, including but not limited to shape, size, location, additive/subtractive, and other characteristics can serve to communicate one or more pieces of information to the user.
Each characteristic can indicate a different piece of information, such that the number of pieces of information that can be communicated is limited only by the number of characteristics of the indicator. For example, location can indicate a first characteristic, location a second characteristic, size a third characteristic, etc. Further, one characteristic could communicate more than one piece of information. For example, location can indicate two or more characteristics, such as one orientation characteristic and one type characteristic. The presence of an indicator on the corner of an optical element may communicate an orientation and that the package is of a first type; the presence of an indicator displaced from the corner toward the center of the optical element may communicate an orientation and that the package is of a second type. Many different embodiments are possible.
Polarity indicators can be particularly useful in cases when a majority of a top surface of a substrate or submount is covered, such as by the encapsulant or optical element. In some embodiments of the present invention, 80% or more of the top surface is covered. In some embodiments 90% or more is covered. In some embodiments 95% or more is covered. In some embodiments, such as the package 40 from
The package 40 comprises an encapsulant 42 which itself comprises and/or is shaped to define and/or has a shape that comprises an indicator 48. The indicator 48 can be, for example, additive or subtractive. These terms are used interchangeably herein unless specifically noted otherwise. The encapsulant can be made of many different materials; one common material is silicone. The integrated indicator 48 can be concave and/or subtractive, and can be formed by creating a void within the encapsulant 42, although other embodiments are possible. In the embodiment shown the indicator 48 is a hemispheric or frustospheric void, although many different shapes are possible, some of which will be described below. In the embodiment shown the indicator 48 has a diameter of about 50 μm to about 1 mm, or about 100 μm to about 500 μm, or about 300 μm, although many different sizes are possible. In one embodiment the diameter is about 500 μm or less.
The indicator 48, and other indicators described herein, can indicate to a technician a particular corner or side of interest. For example, the indicator 48 in
Integrated indicators according to the present invention, such as the indicator 48, can be big enough to be visible to the human eye, while minimizing any effect on the output profile of a package, such as the package 40. For example,
The color output along two axes of the
While the encapsulant 42 is shown as generally rectangularly prismatic and with side walls that taper inward as they rise, it is understood that the encapsulant and other encapsulants described herein comprising indicators can take many different shapes, including hemispheric, frustospheric, cubic, rectangular prismatic, cylindrical, etc. Some encapsulant shapes are described, for example, in U.S. patent application Ser. No. 13/902,080 to Lowes et al. and entitled “Emitter Package with Integrated Mixing Chamber,” which is commonly assigned with the present application and which is fully incorporated by reference herein in its entirety. Polarity indicators according to the present invention can be used in conjunction with encapsulants of any shape.
While the indicator 48 from
A device similar to the package 70 was measured as having an output very similar or identical to the outputs of the packages that are shown in
Embodiments of the present invention can include more than one indicator, and in some embodiments different indicators can indicate different package qualities. For example,
While in the embodiment shown the indicator 88a is an additive frustosphere and the indicator 88b is a subtractive frustocylindrical trench, these indicators can take any shape and any placement that indicates a certain type of orientation and/or package characteristic. In some embodiments including that shown, different shapes are used to indicate different qualities. However, this need not always be the case. For instance, in some embodiments indicator location can be used with indicators of the same shape, such as a corner indicator with a position similar to the indicator 88a indicating a first quality, such as polarity, and a side indicator with a position similar to the indicator 88b indicating another quality, such as primary emission direction. Examples of different pieces of information that can be communicated have been described above, and as with all other indicators described herein, the piece(s) of information communicated by the indicators 88a,88b are in no way limited.
While the encapsulants 42 and 72 from
While the packages shown above include an indicator on a top surface, many different locations are possible. For example, the package 90 in
In some instances, two indicators can be included on an encapsulant. This can in some instances facilitate easier fabrication. In these cases, the indicators can be mirror images of one another, such as the indicators 98a,98b best seen in
Many different methods can be used to fabricate the indicators 98a,98b. For instance, the indicators can be attached to the rest of the optical element 92 after it is already hardened, such as by a welding or molding process. Alternatively, the encapsulant 92 including the indicators 98a,98b can be molded at once, such as by injection molding. Many different methods are possible.
Encapsulants can have different sections of opaqueness and clearness. For example, particles used in embodiments of the present invention, including but not limited to wavelength conversion particles, phosphor particles, scattering particles, and quantum dots, can be distributed in different regions with different types of particles and/or different concentrations of particles. Encapsulants having different particle regions are described in U.S. patent application Ser. No. 12/498,253 to Le Toquin and entitled “LED Packages with Scattering Particle Regions,” and U.S. patent application Ser. No. 13/902,080 to Lowes et al. and entitled “Emitter Package with Integrated Mixing Chamber,” each of which is commonly assigned with the present application and each of which is fully incorporated by reference herein in its entirety.
While an indicator on the top surface of the substrate may be visible when the package is viewed from a certain angle in some embodiments, viewing such an indicator could prove to be difficult and require excessive time and/or effort, unlike an integrated indicator. Thus, the use of an integrated indicator can improve mounting ease and efficiency. For example,
While the above embodiments describe indicators integrated into encapsulants, it is understood that indicators according to the present invention can be included in many different types of elements and optical elements, including but not limited to remote phosphor elements. For instance, indicators can be included in embodiments described in commonly assigned U.S. patent application Ser. No. 14/185,123 to Kircher et al. and entitled “Remote Phosphor Element Filled with Transparent Material and Method for Forming Multisection Optical Elements,” which is fully incorporated by reference herein in its entirety. Some embodiments described in this patent comprise an optical element mounted to a substrate/source arrangement or an LED package. In some of these embodiments, the optical element may block or cover areas where prior art indicators would be included, such as the top surface of the substrate. Optical elements including an integrated indicator may be particularly suited for such cases.
Polarity indicators can also be particularly applicable to emitters that are not on a traditional substrate and/or emitters with a hard or rigid optical element. For example, commonly assigned U.S. patent application Ser. No. 14/053,404 to Heikman et al. and entitled “Chip with Integrated Phosphor,” which is fully incorporated by reference herein in its entirety, describes “virtual wafers” of light emitters held together by converter material and/or one or more other layers. For example,
Whether part of a wafer comprising packages 120 or part of a singular package 120, one or more of the holding layers 121 can provide the primary mechanical support for the package. In this sense, these one or more holding layers 121 can provide the support that would otherwise be provided by a traditional substrate.
In one embodiment the bottom utility layer 124 can be silicone while the top utility layer 126 can be glass, plastic, or silicone. In other embodiments only one layer may be present, such as a layer of glass, silicone, or another material. The use of a material that is more hard and/or rigid than a silicone bottom utility layer 124, such as glasses like borosilicate glass or plastic, can increase the stability of the virtual wafer and/or can decrease or eliminate mechanical distortion due to shrinking of the bottom utility layer during cooling, such as that which may occur after high temperature curing. This process is described more fully in U.S. patent application Ser. No. 14/053,404 to Heikman et al.
In one embodiment, packages such as the package 120 can have a top layer that is shaped to define an integrated indicator, such as the integrated indicator 128. It is understood that while the top layer can be shaped to define an integrated indicator, other layers may also be shaped to define the same indicator. For example, a subtractive indicator may extend beyond the top layer into one or more of the layers below.
While the integrated indicator 128 is substractive, it can be additive in other embodiments, and can have any of the shapes or attributes of integrated indicators previously described. Polarity indicators in packages similar to the package 120 can be formed on a top surface prior to singulation. Alternatively, they can be formed on a side surface of the package, such as after singulation.
Optical elements according to the present invention can be manufactured in many different manners, such as by molding (including overmolding). If being manufactured by molding, the mold cavity can be altered to include an indicator portion. In one specific additive method, an indicator feature can be molded or welded onto the remainder of the encapsulant. Welding or molding can occur during or after the hardening or curing of the encapsulating material, for example. U.S. patent application Ser. No. 14/185,123 to Kircher et al. describes methods of forming multisection optical elements which can be applied to the present invention; for example, the indicator of the present invention can be attached to the remainder of the encapsulant just as different sections of an optical element are attached to one another in U.S. patent application Ser. No. 14/185,123. In another similar method, an optical element, such as a glass optical element, can be softened and reshaped to define an indicator, or can be softened and additional material welded onto or otherwise attached to the main glass element to form the indicator.
In one specific subtractive method, an indicator imprint can be pushed into an optical element to form a subtractive indicator such as the indicator 48 from
Another specific subtractive method is bead blasting or sand blasting. A specific target area of an optical element can be isolated, such as by a metal mask, and blasted with high velocity beads and/or sand to form a subtractive indicator. This method can be used with softer optical elements, such as silicone, but is particularly well adapted for use with harder materials such as glass.
Another method of forming indicators according to the present invention can include imprinting and/or ablation, such as by laser. Although laser methods can be used to form an indicator on any type of optical element, these methods can be particularly applicable to subtractive indicators, optical elements which are not molded, and/or optical elements which comprise a hard material, such as certain glasses including borosilicate glass. For example, this method can be used with packages similar to or the same as the package 120 from
One device that can be used to form indicators according to the present invention is the Universal® Laser Systems VLS Desktop Series, such as the VLS 2.30 or VLS 3.50, the data sheets of which are fully incorporated by reference herein in their entirety. Many other systems can also be used. The intensity of the laser used can depend on a number of factors, including but not limited to the properties of the host material (e.g., hardness, optical properties, thickness, etc.) and the desired properties of the indicator (e.g. depth, width, shape, etc.).
As can be seen using the scale, the top surface corresponds to a reference height of approximately 500-600 μm, or about 550 μm. The bottoms of the holes correspond to a reference height of about 50-150 μm, or about 100 μm. Thus, in this case, the integrated indicators have a depth of about 350-550 μm, or about 450 μm. Many different depths are possible, as previously described. For example, in the previously described frustospherical subtractive indicator 48 from
In the
It should be noted that the streaks through areas 132 and the small circles in the middle of segments 134 represent interference and/or areas of no data, and as such are not indicative of any structure.
Continuous integrated indicators, such as the indicators 144, can be formed on packages so as to indicate one side or corner of the package. For example, in a square package such as those represented in
In the embodiments of the present invention, such as those described above, the integrated indicator can be designed to be visible to the human eye such that it can indicate to a technician the proper alignment of the package. In some embodiments, regardless of whether or not the integrated indicator is visible to the human eye but especially in embodiments where it is not, it may be more efficient to locate the indicator via machine and/or software, such as software with feature identification tools.
The placement of the indicator where it is visible from above (e.g., on a top or side surface of an optical element) can make the identification process easier and more efficient, since otherwise each package would have to be placed over a camera for feature identification, then physically moved to a mounting position. In order to best identify an indicator on the top surface of an optical element according to the present invention, the lens or identification tool should focus upon the elevation of the sought indicator (e.g., the top of the optical element). For instance,
Software can be used in combination with pick-and-place mechanical devices in order to properly orient embodiments of the present invention. For example,
The setup in
It is understood that embodiments presented herein are meant to be exemplary. Embodiments of the present invention can comprise any combination of compatible features shown in the various figures, and these embodiments should not be limited to those expressly illustrated and discussed.
Although the present invention has been described in detail with reference to certain preferred configurations thereof, other versions are possible. Therefore, the spirit and scope of the invention should not be limited to the versions described above.
