THESIS
2010
xvii, 177 p. : ill. (some col.) ; 30 cm
Abstract
Monolithic III-nitride based LED micro-arrays offer many potential applications due to
their superior characteristics such as high brightness, long lifetime and high contrast. In
previously developed passive addressable LED micro-arrays, display dimensions and pixel
brightness were limited by the loading effect in the same row or column. Therefore, a new
addressing scheme and fabrication technology are needed to improve the operation
effectiveness of the LED micro-arrays.
In this thesis, III-nitride based light emitting diodes on silicon (LEDoS) displays were
designed and fabricated by integrating LED micro-arrays and active matrix substrates through
Flip-Chip technology. An active matrix driving scheme was designed to provide sufficient
drive capability and individual contro...[
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Monolithic III-nitride based LED micro-arrays offer many potential applications due to
their superior characteristics such as high brightness, long lifetime and high contrast. In
previously developed passive addressable LED micro-arrays, display dimensions and pixel
brightness were limited by the loading effect in the same row or column. Therefore, a new
addressing scheme and fabrication technology are needed to improve the operation
effectiveness of the LED micro-arrays.
In this thesis, III-nitride based light emitting diodes on silicon (LEDoS) displays were
designed and fabricated by integrating LED micro-arrays and active matrix substrates through
Flip-Chip technology. An active matrix driving scheme was designed to provide sufficient
drive capability and individual controllability of each LED pixel. Three generations of the
LEDoS displays were introduced and demonstrated.
Firstly, an 8×8 monolithic LEDoS display was fabricated with an emission wavelength of 440nm. The pixel size was 300μm by 300μm in a square shape with a 350μm pitch. The
LEDoS display panel was measured by applying scan and data signals, demonstrating
sufficient driving capability for the LED micro-array. Secondly, an 8×8 LED micro-array unit
was designed as a basic module. With this module, the LEDoS display panel can be scaled up
to 16×16, 24×24 or even bigger according to full-custom designs of the active matrix
substrates. Forward voltage uniformity of the LED pixels was greatly improved using a novel
double-ground structure. Red, green and blue phosphors were applied on the top of the
LEDoS panel to realize a full-color display. Thirdly, high-resolution and fine-pixel LED
micro-arrays were designed with either 30×30 or 60×60 pixels on a single chip. The circular
shape pixels had diameter of diameter of 100μm in 140μm pitch and 50μm in 70μm pitch,
respectively. With a peripheral driving board, the LEDoS micro-display panel was
programmed row by row and column by column individually. Representative images, numeric
and alphabets were displayed. The LEDoS has potential applications such as micro-displays,
portable projectors, bio-sensor arrays, back-light units for LCDs and programmable lighting
sources.
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