Vertical integration of light-emitting diode chips

A novel design and method for assembling a tri-color light-emitting diode (LED) device is proposed and demonstrated. LED chips of the primary colors are physically and tightly stacked on top of each other, enabled by laser-micromachined trenches on the backside of chips. Light emitted from each layer of the stack passes through each other, and thus is mixed naturally without additional optics. As a color-tunable device, a wide range of colors can be generated, making it suitable for display purposes. As a phosphor-free white light LED, both high luminous efficacy and CRI was achieved. © 2011 IEEE.link_to_subscribed_fulltex