CN103081132B - Light-emitting diode display with the LED component for tilting peak emission and comprising such devices - Google Patents

Abstract

An LED package and lead frame comprising a reflective cup having a bottom surface, wherein the LED is positioned asymmetrically on the bottom surface, and a wall surface that is inclined relative to the bottom surface and defines an opening at its upper end. The bottom surface of the reflective cup has a first axial dimension along a first axis and a second axial dimension along a second axis, the second axis being perpendicular to the first axis. A display having an asymmetric FFP and an asymmetric screen curve includes an array of LED modules including a plurality of LED packages. At least some LED packages contain a dome-shaped lens positioned asymmetrically with respect to the geometric center of the bottom surface of the reflective cup.

Description

LED devices with sloped peak emission and LED displays comprising such devices

technical field

The present disclosure relates generally to light emitting diodes (LEDs), and more particularly, to LED devices having sloped peak emission, and to LED displays including such devices.

Background technique

In recent years, LED technology has advanced significantly, so that LEDs with enhanced brightness and color fidelity have been adopted. Thanks to these improved LEDs and improved image processing techniques, large-size, full-color LED video screens have become available and are now commonly used. Large format LED displays typically comprise a combination of individual LED panels, providing an image resolution determined by the distance between adjacent pixels, or "pixel pitch."

Outdoor displays, which are intended to be viewed from greater distances, have relatively large pixel pitches and typically include discrete arrays of LEDs. In discrete LED arrays, groups of individually mounted red, green, and blue LEDs are driven to form full-color pixels that are displayed to a viewer. LED-based large-screen displays (often referred to as giant screens) are becoming more common in many indoor and outdoor venues, such as at sporting events, racetracks, concerts, and large public areas such as Times Square in New York City . Many of these displays or screens can be as large as 60 feet high and 60 feet wide. These screens can include thousands of "pixels" or "pixel modules," each of which can contain multiple LEDs. The pixel modules use highly efficient and bright LEDs to enable the display to be viewed from a relatively long distance, even when it is illuminated by the sun during the day. A pixel module can have as few as three or four LEDs (one red, one green, and one blue), which allow the pixel to emit multiple different colors of light through combinations of red, green, and/or blue light. In the largest jumbo screens, each pixel module can have many LEDs. The pixel modules are arranged in a rectangular grid. For example, a grid can be 640 modules wide and 480 modules high, and the final size of the screen depends on the actual size of the pixel modules.

Traditional LED-based displays are controlled by a computer system that receives an input signal (such as a TV signal) and forms an overall display image based on the particular color desired at the pixel modules. The computer system decides which LEDs in each pixel module emit light And how bright it is. A power system may also be included that provides power to each pixel module and the power to each LED can be adjusted so that it emits light at a desired brightness. Conductors are provided to apply appropriate power signals to each LED in the pixel module.

The vast majority of these giant screens are typically mounted at a height above the observer's eye level, such as on the side of a building or on top of a bleacher in a sports arena. Therefore, most of the light emitted by the display is not seen by the viewer and is wasted. Additionally, the wasted light can lead to light pollution by creating unwanted light reflections and/or glare. One way to reduce the amount of wasted light is by mounting the display at an angle to better match the viewer's line of sight, but this requires complex and expensive mounting hardware which is difficult to apply, especially for installations at high heights very large monitors.

Contents of the invention

It is an object of the present disclosure to provide an improved LED device that increases the efficiency of light emitted by large LED displays. The disclosed LED devices and LED displays can also save energy and reduce light pollution.

One embodiment of an LED package includes a reflective cup having a bottom surface and a wall surface, the wall surface being inclined relative to the bottom surface and defining an opening at its upper end. LEDs are mounted on the bottom surface. The bottom surface of the reflective cup has a first axial dimension of about 0.91 mm to 1.1 mm along a first axis and a second axial dimension of about 0.66 mm to about 0.91 mm along a second axis perpendicular to the first axis.

Another embodiment discloses a display that includes a lead frame including a reflective cup having a bottom surface and a wall that is sloped relative to the bottom surface and defines an opening at an upper end thereof. The bottom surface has a first axial dimension of about 0.91 mm to about 1.1 mm along a first axis and a second axis of about 72% to about 100% of the first axial dimension along a second axis perpendicular to the first axis to size.

Yet another embodiment discloses a display comprising a substrate carrying an array of light emitting diode (LED) packages arranged in vertical columns and horizontal rows. At least one of the LED packages has a lead frame with a reflective cup. The reflective cup has a bottom surface and a wall surface, the wall surface is inclined relative to the bottom surface and defines an opening at its upper end. There are LEDs mounted on the bottom surface. The bottom surface has a first axial dimension of about 0.91 mm to about 1.1 mm along a first axis and a second axial dimension of about 0.66 mm to about 0.91 mm along a second axis perpendicular to the first axis. The display further includes signal processing and LED driver circuitry electrically connected to selectively energize the array of LED packages to produce a visible image on the display.

A further embodiment discloses an LED package comprising a reflective cup having a bottom surface and a wall surface, the wall surface being inclined relative to the bottom surface and defining an opening at an upper end thereof. LEDs are mounted on the bottom surface. The bottom surface has a first axial dimension along a first axis and a second axial dimension along a second axis perpendicular to the first axis. The bottom surface has a curved border portion and a straight border portion. The length of the curved portion is much greater than half the circumference of the bottom surface.

Yet another embodiment discloses an LED package comprising a reflective cup having a bottom surface and a wall surface, the wall surface being sloped with respect to the bottom surface and defining an opening at an upper end thereof. LEDs are mounted on the bottom surface. The bottom surface of the elliptical reflective cup has a first axial dimension of less than about 0.89 mm and a second axial dimension of less than about 0.64 mm along a second axis perpendicular to the first axis.

Description of drawings

FIG. 1 is a top view of an LED device according to an embodiment of the present disclosure;

Figure 2 is a cross-sectional view of the embodiment shown in Figure 1, taken along section line 2-2;

Figure 3 is a cross-sectional view of the embodiment in Figure 1, taken along viewing line 3-3;

4 is a top view of an LED device according to another embodiment of the present disclosure;

5 is an illustration of a partially cut-away cross-sectional view of a lens-covered LED, taken along viewing line 5-5;

6 is a first side cross-sectional view of a lens covering an LED device;

Fig. 7 is a sectional view of the lens in Fig. 6;

8 is a second side view of the lens covering the LED device in FIG. 6;

Fig. 9 is a top view of the lens in Fig. 6;

10 is a plan view of a portion of an LED display screen including LED devices according to an embodiment of the present disclosure;

Fig. 11 is an illustration related to the observer of the LED display screen of Fig. 10;

Figure 12(a) is a plot of the horizontal far field pattern of an LED device according to one embodiment of the present disclosure.

Figure 12(b) is a plot of the horizontal far-field pattern versus the first negative viewing angle for an LED device according to one embodiment of the present disclosure;

Figure 12(c) is a plot of the horizontal far-field pattern versus the second negative viewing angle for an LED device according to one embodiment of the present disclosure;

Figure 12(d) is a plot of the vertical far-field pattern of an LED device according to one embodiment of the present disclosure;

Figure 13(a) is a plot of the horizontal screen curve (screen curve) of the LED screen according to one embodiment;

Figure 13(b) is a plot of the horizontal screen curve of an LED device according to an embodiment of the present disclosure versus the first negative viewing angle;

Figure 13(c) is a plot of the horizontal screen curve of an LED device according to an embodiment of the present disclosure versus a second negative viewing angle;

Figure 13(d) is a plot of the vertical screen curve of an LED device according to one embodiment of the present disclosure.

detailed description

The following description presents preferred embodiments of the disclosure, showing the best mode contemplated for carrying out the disclosure. This description is not for purposes of limitation, but merely for the purpose of describing the general principles of the disclosure, the scope of which is defined by the appended claims.

Embodiments of the invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. However, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood that when an element such as a layer, region, or substrate is referred to as being “on” or extending “onto” another element, it can be directly on the Either it extends directly onto another element or intermediate elements can also be present. In contrast, when an element is referred to as being "directly on" or extending "directly onto" another element, there are no intervening elements present. It will also be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

Related terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" can be used herein The relationship of one element, layer or region to another element, layer or region shown in the figures is described. It will be understood that these terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures.

The terminology employed herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural unless the context clearly dictates otherwise. It should be further understood that when the terms "comprises", "comprising", "includes" and/or "including" are used herein, they refer specifically to claimed features, general , steps, operations, elements and/or parts, but does not exclude the existence or addition of one or more features, integers, steps, operations, elements, parts and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It should be further understood that the terms used herein should be interpreted as having a meaning consistent with the meaning in this specification and the content in the relevant technical field, and should not be interpreted as an idealized or overly formal meaning, unless is expressly defined herein.

1-3 depict one embodiment of an LED package 10 in different views. 1 is a top view of an LED package 10 showing a reflective cup 20 having a bottom surface 22 and a wall 23 that is inclined relative to the bottom surface 22 and defines an opening 24 at the upper end of the reflective cup 20 . LEDs 30 are mounted on bottom surface 22 . The bottom surface 22 has a first axial dimension 26 along a first axis 40 and a second axial dimension 28 along a second axis 50 perpendicular to the first axis 40 . In some embodiments, preferably, the first axial dimension 26 is from about 0.91 mm to about 1.1 mm, and the second axial dimension 28 is from about 0.66 mm to about 0.91 mm. More preferably, the first axial dimension 26 is from about 0.95mm to about 1.05mm, and the second axial dimension 28 is from about 0.75mm to about 0.85mm.

In accordance with the present disclosure, it is contemplated that reflective cup 20 is sized to be manufactured with extremely tight dimensional tolerances. These tight tolerances are limited only by the manufacturing capabilities of the stamping process used to form the reflective cup and the leadframe assembly process, and are limited to the smallest finite dimensions of the LED 30 . Accordingly, in other embodiments, the first axial dimension 26 is less than about 0.89 mm, and the second axial dimension 28 is less than about 0.64 mm. Further, the first axial dimension 26 can be less than about 0.85 mm and the second axial dimension 28 is less than about 0.6 mm. Still further, first axial dimension 26 and second axial dimension 28 are about the same length as LED 30 with a slightly increased dimension to allow electrical connection of LED 30 and performance characteristics consistent with the devices disclosed herein. light propagation.

In one embodiment, the area of the bottom surface 22 is larger than the area of the bottom surface of the LED 30 and smaller than the area of the opening 24 . In other embodiments, the ratio of the first axial dimension 26 to the second axial dimension 28 can range from about 1:1 to about 11:7. For example, the ratio of the first axial dimension 26 to the second axial dimension 28 can be about 5:4. Preferably, in some embodiments, the second axial dimension 28 is from about 72% to about 100% of the first axial dimension 26 . More preferably, the second axial dimension 28 is approximately 75% to 90% of the first axial dimension 26 . Most preferably, the second axial dimension 28 is approximately 78% to 85% of the first axial dimension 26 .

The opening 24 also has a first axial dimension 32 along a first axis 40 and a second axial dimension 34 along a second axis 50 , which is perpendicular to the first axis 40 . Preferably, the first axial dimension 32 is from about 1.3mm to about 1.5mm and the second axial dimension 34 is from about 0.94mm to about 1.14mm. More preferably, the first axial dimension 32 is from about 1.35mm to about 1.45mm and the second axial dimension 34 is from about 0.99mm to about 1.09mm.

Consistent with the assumption that within manufacturing tolerances and the finite dimensions of LED 30 define dimensional characteristics, the size of opening 24 will remain relative to the size of bottom surface 22 so that light propagation is consistent with the performance characteristics of the devices disclosed herein. Accordingly, in other embodiments, the first axial dimension 32 is less than about 1.25 mm and the second axial dimension 34 is less than about 1.00 mm. Further, the first axial dimension 32 can be less than about 1.2 mm, and the second axial dimension 34 is less than about 0.95 mm.

In the embodiments disclosed herein, the first dimension is longer than the second dimension so that the viewing angle along the first axis 40 is wider than the viewing angle along the second axis 50 . For example, the first axial dimension 26 is longer than the second axial dimension 28 by about 0.2 mm to about 0.4 mm. For example, LED 30 can have a horizontal viewing angle along first axis 40 of approximately -60° to +60°. As used herein, the term "view angle" is the angular range over which the intensity of light emitted by an LED in a far field pattern (FFP) is approximately 50% of the peak intensity. FFP is an optical characteristic of an LED and represents the luminous intensity in space. Most commonly, FFP indicates the normalized ratio of luminous intensities at different radiation angles. In this embodiment, the LED package 10 is modified to produce an asymmetric FFP in a first direction and a uniform FFP in a second direction. Additional features of asymmetrically positioned LEDs and reflective cup designs are disclosed in applicant's co-pending U.S. patent application Ser. No. 12/498,277 and co-pending U.S. patent application Ser. No. 12/868,567, the disclosures of which are incorporated by reference at this.

LED 30 , when arranged at the geometric center of the bottom surface, can have a vertical viewing angle of about -28° to +28° along second axis 50 . When the LED 30 is displaced (displaced) away from the geometric center of the bottom surface 22, which in FIG. 1 is the intersection between the first axis 40 and the second axis 50, the LED 30 can have vertical viewing angle and peak intensity at approximately -20°. In this case, the viewing angle is tilted at approximately -20°. As used herein, the term "geometrical center" of a surface is defined as the centroid of a planar pattern or, in other words, the intersection of a line dividing a planar pattern into two parts of the same moment. In the context of the devices disclosed herein, in some embodiments, the planar pattern is the opening of a reflective cup.

In some embodiments, the geometric center of the bottom surface 22 can coincide with or overlap the intersection of the first axis 40 and the second axis 50 to produce a relatively small oblique viewing angle. However, the geometric center of the bottom surface 22 can also be displaced away from the intersection of the first axis 40 and the second axis 50 to obtain relatively large oblique viewing angles. Similarly, in some embodiments, the geometric center of opening 24 can coincide with or overlap the intersection of first axis 40 and second axis 50 , resulting in a relatively small oblique viewing angle. Further, in some embodiments, the geometric center of opening 24 can be displaced away from the intersection of first axis 40 and second axis 50 , resulting in a relatively large oblique viewing angle.

Figure 2 is a cross-sectional view of the embodiment of Figure 1, taken along section line 2-2. LED 30 is mounted on bottom surface 22 in reflective cup 20 . In the illustrated embodiment, the reflective cup 20 has a depth of preferably about 0.2 mm to about 0.3 mm, so that the wall 23 has a height "h" of about 0.2 mm to about 0.3 mm. In some embodiments, height "h" can be less than about 0.2 mm. In other embodiments, the height "h" can be less than about 0.15 mm. Further, the height h can range from about 0.16 mm to about 0.24 mm. Consistent with the assumption of a minimum size feature of reflective cup 20 , height "h" can only be as large as to accommodate the profile height of LED 30 . In some embodiments, height "h" can be even less than the profile height of LED 30 . A vertical axis 60 extends through the center of reflective cup 20 .

LED package 10 includes a lead frame having bond pads 70 and 80 that are conductively connected to leads 76 and 86, respectively. Further, the reflective cup 20 has a wall 44 which is conductively connected to the LED chip 30 and the lead 86 . Wall 44 can have a non-uniform thickness and the material of construction of wall 44 and leads 76 and 78 can be copper, iron, or other conductive material that also dissipates heat. Thermal spreading is advantageous because LED package 10 is capable of producing peak luminous intensities up to about 3000 mcd. Notably, the operating current is less than about 20mA. The operating current can be less than about 10 mA.

Figure 3 shows a cross-sectional view of the LED package 10 of Figure 1, taken along section line 3-3. As can be seen in FIG. 3 , LEDs 30 are offset from vertical axis 60 . Referring to FIGS. 1-3 , the LED package 10 has a reflective cup 20 including a bottom surface 22 and a wall surface 23 , and the wall surface is inclined relative to the bottom surface 22 . The reflective cup 20 can have an oval shape or a generally circular shape. The inclination of the wall surface 23 relative to the bottom surface 22 changes continuously, so that the wall surface 23 has a relatively steep portion 48 and a relatively shallow portion 46 . In FIG. 3 , the relatively steep portion 48 can be near the lower portion of the reflective cup 20 and the relatively gentle portion 46 can be near the upper portion of the reflective cup 20 . For example, the wall surface 23 defines a first angle 54 between the steep portion 48 and a plane 52 extending outwardly from the bottom surface 22 , and a second angle 56 between the gentle portion 46 and the plane 52 . Preferably, angle 56 is inclined at about 40° to about 50° relative to bottom surface 22 and angle 54 is inclined at about 50° to about 85° relative to bottom surface 22 . More preferably, the first angle 54 may be from about 75° to about 85°, and the second angle may be from about 42° to about 48°. Further, the first angle 54 can be greater than the second angle 56 so that, for example, more light is reflected from the upper portion of the reflective cup 22 toward a lower viewing angle.

4 is a top view of an LED device according to another embodiment of the present disclosure, and FIG. 5 shows a cross-sectional view of the embodiment in FIG. 4, taken along section line 5-5. Similar to the previous embodiments, the LEDs 30 are offset relative to the vertical axis 60 . As seen in FIGS. 4 and 5 , the bottom surface 22 has a straight border portion on its lower side and a curved border portion on its upper side. The curved border portion is longer than the straight border portion. The curved border portion of the bottom surface 22 has a length greater than half the circumference of the bottom surface 22 . Similarly, the opening 24 has a straight border portion on the lower side and a curved border portion on the upper side. Preferably, the curved border portion of the opening 24 has a length greater than half the circumference of the bottom surface 24 . Correspondingly, the angle 54 in FIG. 5 can be slightly smaller than in the first embodiment in FIGS. 1-3 . For example, angle 54 is preferably from about 50° to about 75°, more preferably from about 55° to about 65°, and most preferably from about 57° to about 63°.

FIG. 6 shows reflective cup 20 covered by lens 62 and FIGS. 7-9 show different views of lens 62 . The lens 62 preferably has a dome-shape positioned asymmetrically with respect to the geometric center of the bottom surface 22 . Lens 62 can have a profile height of preferably about 5.3mm to about 7.3mm, more preferably about 5.8mm to about 6.8mm, and most preferably about 6.0mm to about 6.6mm. Two vertical axes 64 and 65 are shown in FIGS. 6 and 7 . Axis 64 is vertically aligned with the geometric center 66 of the lens, and axis 65 is vertically aligned with the lens cross-sectional center 64 taken at the bottom of lens 62 near section line 9-9 of FIG. 7 . The lens 62 has a circular upper surface 68 joined to an associated vertical wall 69 . Upper surface 68 has a geometric center 66 at the intersection of axis 64 and upper surface 68 . The distance 76 between the axis 64 and the axis 65 is about 0.2 mm to about 0.4 mm. For example, the geometric center 66 can be displaced about 0.2 mm to about 0.4 mm away from the geometric center of the bottom cross-section of the lens along section line 9 - 9 , as shown in FIGS. 7 and 9 . Preferably, distance 76 is from about 0.25 mm to about 0.35 mm, and more preferably, from about 0.27 mm to about 0.33 mm. Accordingly, the profile of lens 62 is slightly skewed in one direction and as seen in FIG. 9 , lens 62 has an approximately oblong cross-sectional profile with a slightly flatter side and a relatively more rounded side.

Figure 10 is a plan view of a portion of an LED display 100, for example an outdoor display comprising a driver PCB 102 carrying a number of substrates 104 arranged in rows and columns. The display screen 100 is segmented into a plurality of pixels 110, each pixel comprising a substrate 104 having at least red, blue, and green LEDs 106 thereon. Each pixel of the display can have dimensions of about 10mm by about 10mm or more. Further, each substrate 104 can be driven by a different voltage level. Substrate 104 contains at least some LEDs 106 having the design features described above. The substrate 104 is electrically connected to metal lines or pads (not shown) on the PCB 102, which connect the LEDs to suitable electrical signal processing and driving circuits (not shown). There may be holes 108 between pixels 110 for anchoring PCB 102 to a mounting platform.

To save energy and reduce light pollution, the display includes at least one substrate 104 with LED devices 106 having reflective cups as disclosed above. FIG. 11 shows LED display 100 with viewer 140 in a viewing position below horizontal projection line 120 . Horizontal projection line 120 represents a line substantially perpendicular to the viewing plane of display 100 . The angle θ between the line of sight 130 and the horizontal projection line 120 is defined as the viewing angle relative to the display 100 . Further, because the observer 140 is located below the horizontal line 120, the viewing angle θ has a negative value.

12(a-c) illustrate the horizontal FFP of LED 106 at viewing angles of about 0°, about -18°, and about -36°, respectively. FIG. 12( d ) shows the vertical FFP of LED 106 . In each of Figures 12(a-d), two curves depict LEDs emitting different colors. For example, curves 152, 156, 160, and 172 depict LEDs that emit red light, while curves 154, 158, 162, and 174 depict LEDs that emit green light. As can be seen in Figures 12(a-d), curves 152, 156, 160, and 172 match curves 154, 158, 162, and 174, respectively. Accordingly, LEDs constructed according to the present disclosure emit light of different colors and have very similar FFPs at different viewing angles. In some embodiments, the disclosed LED packages have a peak FFP of about 3000 mcd at a viewing angle of about -18°. The corresponding operating current is less than about 20mA. In some embodiments, the operating current can be less than about 10 mA. For example, to emit a peak luminescence of approximately 1253mcd, the disclosed LED package has an operating current of approximately 8.4mA. Therefore, approximately 32% power can be saved by employing the disclosed LED package.

A screen curve is an optical characteristic of a display screen that indicates the normalized ratio of luminous intensities at different radiation angles. Those skilled in the art recognize that it is advantageous if the screen curves for the different colors produced by the LED display are closely matched. 13(a-c) show the horizontal screen curves of the LED display 100 at viewing angles of about 0°, about -18°, and about -36°, respectively. FIG. 13( d ) shows the vertical screen curve of the LED display 100 . In each of Figures 13(a-d), two curves describe LEDs emitting different colors. For example, curves 176, 180, 184, and 188 depict screen curves when all pixels of LED display 100 emit red light. Correspondingly, curves 178, 182, 186, and 190 depict screen curves when all pixels of LED display 100 emit green light. Since curves 176, 180, 184, and 188 match curves 178, 182, 186, and 190, respectively, LED display 100 is expected to exhibit very similar screen curves when emitting different colors.

Further, the LED display 100 has a relatively wide horizontal viewing angle centered around 0°. Correspondingly, the LED display 100 has a relatively narrow vertical viewing angle centered at about -8° to about -28°. More preferably, LED display 100 has a relatively narrow vertical viewing angle centered at about -13° to about -23°, and most preferably, a relatively narrow vertical viewing angle centered at about -18°.

From the foregoing, it can be seen that the embodiments provide an LED package comprising a reflective cup having a bottom surface and a wall surface, the wall surface being inclined relative to the bottom surface and defining an opening at its upper end. The LEDs are mounted on the bottom surface and can be at least partially covered by the asymmetric lens. Light emitted by the LED packages disclosed herein is thus oblique and directed towards the eyes of a viewer located below an LED display containing LED packages arranged in accordance with the present disclosure. Further, the amount of wasted light is reduced in giant display screens incorporating the disclosed LED packages.

It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and it should be understood that the following claims, including all equivalents, are intended to define the spirit and scope of this disclosure.

Claims (40)

1. A light emitting diode (LED) package comprising: a reflective cup having a bottom surface and a wall surface inclined relative to the bottom surface and defining an opening at an upper end thereof, wherein the bottom surface includes a single straight border portion and a curved border portion; and LED, mounted on the bottom surface, wherein said bottom surface has a first axial dimension along a first axis and a second axial dimension along a second axis perpendicular to said first axis, said first axis extending parallel to said straight border portion ,and wherein the LED is closer to the curved boundary portion where the second axis intersects the curved boundary portion than where the second axis intersects the straight boundary portion. Where the boundary parts intersect. 2. The light emitting diode (LED) package of claim 1, wherein the first axial dimension is 0.2 mm to 0.4 mm longer than the second axial dimension. 3. The light emitting diode (LED) package of claim 1, wherein an area of the bottom surface is larger than an area of the bottom surface of the LED and smaller than an area of the opening. 4. The light emitting diode (LED) package of claim 1, wherein the first axial dimension is 0.95 mm to 1.05 mm. 5. The light emitting diode (LED) package of claim 1, wherein the second axial dimension is 0.75 mm to 0.85 mm. 6. The light emitting diode (LED) package of claim 1, wherein the wall has a height of 0.2 mm to 0.3 mm. 7. The light emitting diode (LED) package of claim 1, wherein the intersection of the first and second axes is located away from a geometric center of the bottom surface. 8. The light emitting diode (LED) package of claim 1, wherein an intersection of the first and second axes coincides with a geometric center of the bottom surface. 9. The light emitting diode (LED) package of claim 1, wherein a geometric center of the opening is displaced away from the intersection of the first and second axes. 10. The light emitting diode (LED) package of claim 1, wherein a geometric center of the opening coincides with an intersection of the first and second axes. 11. The light emitting diode (LED) package of claim 1, wherein a wall extending away from the wall surface has a non-uniform thickness. 12. The light emitting diode (LED) package of claim 11, wherein an inclination of the wall surface with respect to the bottom surface varies such that the wall surface has a steep portion and a gentle portion. 13. The light emitting diode (LED) package of claim 12, wherein the gentle portion is inclined at an angle of 40° to 50° relative to the bottom surface, and the steep portion is inclined at an angle of 50° to 75° ° The angle is inclined with respect to the bottom surface. 14. The light emitting diode (LED) package of claim 2, wherein a ratio of the first axial dimension to the second axial dimension is 5:4. 15. The light emitting diode (LED) package of claim 1, further comprising a dome-shaped lens positioned asymmetrically with respect to a geometric center of the bottom surface and covering the reflective cup. 16. The light emitting diode (LED) package of claim 15, wherein the lens has an asymmetrical cross-section having a first dimension of 3.5 mm to 4.5 mm and perpendicular to the first dimension. Second dimension of 2.5mm to 3.5mm. 17. The light emitting diode (LED) package of claim 16, wherein the lens has a profile height of 5.3 mm to 7.3 mm. 18. The light emitting diode (LED) package of claim 15, wherein the lens has a circular upper surface with a geometric center displaced away from a base cross-section with respect to the lens 0.2mm to 0.4mm geometric center. 19. The light emitting diode (LED) package of claim 15, wherein the light emitting diode (LED) package produces a peak luminous intensity of 3000 mcd and has an operating current of less than 20 mA. 20. A display comprising: a substrate carrying an array of light emitting diode (LED) packages arranged in vertical columns and horizontal rows; At least one of said light emitting diode (LED) packages includes a lead frame having a reflective cup having a bottom surface and a wall surface inclined relative to the bottom surface and defining an opening at an upper end thereof , wherein the bottom surface includes a single straight boundary portion and a curved boundary portion; LEDs mounted on the bottom surface, wherein the bottom surface has a first axial dimension along a first axis and a second axial dimension along a second axis perpendicular to the first axis, the first axis extending parallel to the straight border portion, and wherein the LED is closer to the curved border portion than a location on the straight border portion where the second axis intersects the straight border portion where said second axis intersects said curved boundary portion; and Signal processing and LED driver circuitry is electrically connected to selectively energize the array of light emitting diode (LED) packages to produce a visible image on the display. 21. The display of claim 20, wherein an area of the bottom surface is larger than an area of the bottom surface of the LED and smaller than an area of the opening. 22. The display of claim 21, wherein a ratio of the first axial dimension to the second axial dimension is in the range from 1:1 to 11:7. 23. The display of claim 20, wherein the first axial dimension is 0.2mm to 0.4mm longer than the second axial dimension. 24. The display of claim 23, wherein the display has an asymmetric far-field pattern with a peak luminous intensity below a horizontal central axis of the display. 25. The display of claim 20, wherein the first axial dimension is 0.95 mm to 1.05 mm. 26. The display of claim 20, wherein the second axial dimension is 0.75mm to 0.85mm. 27. A lead frame comprising: a reflective cup having a bottom surface and a wall surface inclined relative to the bottom surface and defining an opening at its upper end, wherein the bottom surface includes a single straight border portion and a curved border portion, wherein the bottom surface has a first axial dimension along a first axis and a second axial dimension along a second axis perpendicular to the first axis which is 72% to 100% of the first axial dimension , the first axis extends parallel to the straight boundary portion, and wherein the LED is closer to the curved boundary portion on the second axis than to a position on the straight boundary portion where the second axis intersects the straight boundary portion The location of the intersection. 28. The leadframe of claim 27, wherein the first axial dimension is 0.95 mm to 1.05 mm. 29. The lead frame of claim 27, wherein the second axial dimension is 0.75 mm to 0.85 mm. 30. The lead frame of claim 27, wherein the reflective cup has a depth of 0.2 mm to 0.3 mm. 31. The lead frame of claim 27, wherein a wall extending from the wall surface has a non-uniform thickness. 32. The lead frame of claim 27, wherein the curved border portion is longer than the straight border portion. 33. The leadframe of claim 27, wherein the second axial dimension is 80% of the first axial dimension. 34. A light emitting diode (LED) package comprising: a reflective cup having a bottom surface and a wall inclined relative to the bottom surface and defining an opening at its upper end; and LED, mounted on the bottom surface, wherein the bottom surface has a first axial dimension along a first axis and a second axial dimension along a second axis perpendicular to the first axis, the bottom surface has a curved border portion and a single straight border portion , the curved portion has a length greater than half the perimeter of the bottom surface, wherein said bottom surface has a first axial dimension of 0.91 mm to 1.1 mm along a first axis and a second axial dimension of 0.66 mm to 0.91 mm along a second axis perpendicular to said first axis, and wherein the LED is closer to the curved boundary portion where the second axis intersects the curved boundary portion than where the second axis intersects the straight boundary portion. Where the boundary parts intersect. 35. The light emitting diode (LED) package of claim 34, wherein the straight border portion has a length that is less than the first axial dimension. 36. A light emitting diode (LED) package comprising: a reflective cup having a bottom surface and a wall surface inclined relative to the bottom surface and defining an opening at an upper end thereof, wherein the bottom surface includes a single straight border portion and a curved border portion; and LED, mounted on the bottom surface, Wherein, the bottom surface has a first axial dimension of less than 0.89 mm along a first axis and a second axial dimension of less than 0.64 mm along a second axis perpendicular to the first axis, the first axes being parallel to extends along the straight boundary portion, and wherein the LED is closer to the curved boundary portion where the second axis intersects the curved boundary portion than where the second axis intersects the straight boundary portion. Where the boundary parts intersect. 37. The light emitting diode (LED) package of claim 36, wherein the wall has a height of less than 0.25 mm. 38. The light emitting diode (LED) package of claim 37, wherein the height is less than 0.2 mm. 39. The light emitting diode (LED) package of claim 37, wherein the height is less than 0.15 mm. 40. The light emitting diode (LED) package of claim 37, wherein the height is 0.16 mm to 0.24 mm.