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LEDs with shaped growth substrates for side emission

A technology for growing substrates and emitting light, applied in semiconductor devices, electrical components, circuits, etc., can solve problems such as reducing the efficiency of LED modules

Active Publication Date: 2018-06-22
LUMILEDS HLDG BV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] Since the vast majority of all light emitted by the LED die 10 passes through its top surface, and almost half of the light emitted by the phosphor above the LED die 10 is directed downward toward the LED die 10, there is A large amount of light absorbed, which reduces the efficiency of the LED module

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  • LEDs with shaped growth substrates for side emission
  • LEDs with shaped growth substrates for side emission
  • LEDs with shaped growth substrates for side emission

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Embodiment Construction

[0028] The present technology can be applied to many types of different LEDs, and an example of an LED structure will be described to illustrate the application of the present invention. In an example, the LEDs are GaN-based LEDs that emit blue light. Suitable transparent growth substrates for GaN-based LEDs are typically sapphire, SiC or GaN.

[0029] figure 2 A sapphire growth substrate wafer 42 is illustrated. Such wafers are available in diameters between 2-6 inches, although larger wafers are contemplated and included within the scope of the present invention. Since a typical LED is only about 1mm 2 , so thousands of LEDs can be formed on a single wafer 42. Typical thicknesses of such wafers are less than 100 microns, or the minimum thickness considered necessary by the manufacturer for mechanical support of the LED layers during processing. In this process, however, a much thicker wafer 42 is used to accommodate the depth of the side-emitting optical features and c...

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Abstract

An array of optical features is formed in the surface of a relatively thick growth substrate wafer. The LED layers are epitaxially grown on opposite surfaces of the growth substrate wafer. The LED layer includes an active layer that emits light toward the growth substrate wafer. The resulting LED wafer is singulated to form individual LED dies having growth substrate portions each having at least one optical feature. The optical features redirect a substantial portion of the light emitted from the active layer to exit the LED die through the sidewalls of the growth substrate portion. A side-emitting LED die is mounted in a reflective cup and encapsulated with a phosphor material. The LED light thus excites the phosphor particles that do not overlap the LED die, so less phosphor light is absorbed by the LED die and efficiency is improved.

Description

technical field [0001] The present invention relates to light emitting diodes (LEDs), and in particular to techniques for providing LEDs with enhanced side emission. Background technique [0002] The vast majority of all light emitted from an LED die is from its top surface opposite the LED's mounting surface. This essentially creates a pinpoint type of light because the top surface area is within 1mm 2 on the order of magnitude. [0003] figure 1 Indicates a common use for LEDs in reflective cups used to direct light in specific directions, such as LED flashes used in smartphone cameras. figure 1 is a cross-sectional view of a typical flip-chip LED die 10 with its anode contact 12 and its cathode contact 14 formed on the bottom surface of the die 10 . Contacts 12 and 14 occupy a large area of ​​the bottom surface of LED die 10 and are reflective. Die 10 may optionally be mounted on a substrate with more robust metal pads for bonding to electrodes of package 20 . [00...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L33/00H01L33/20H01L33/46
CPCH01L33/20H01L33/46H01L33/0093H01L2224/16145H01L2224/16245H01L33/405H01L33/62H01L33/60H01L33/505H01L33/0066H01L33/0095H01L2933/0033H01L2933/0041H01L2933/0016H01L2933/0058H01L2933/0066
Inventor M.M.布特沃思
Owner LUMILEDS HLDG BV