Adaptive Driving Beam (ADB) applications are proliferating from premium vehicles into the mainstream car models. Technology advances are creating the inflection point enabling cost effective digital headlighting to replace light steering by electro-mechanical swiveling shutters. Today’s LED matrix solutions support the mainstream ADB functionality with 5-25 independently addressable pixels. Meanwhile, the premium segment is evolving to a pixel count in the thousands to the one million range driven by additional functional value in beam content. We can predict the usual functionality migration from premium to mainstream segment and hence anticipate the adoption of increasing pixel count ADB solutions in the mainstream to support increased functionality, but at the appropriate cost point. Given the emerging range of high pixel count solutions today and an equally wide range of emerging technologies which support these, it is useful to shed light on which of these solutions have the potential to meet the mainstream requirements. This is the motivation for the work presented in this paper. We will look at all of the major competing technologies and offer an analysis on which technologies could support the requirements to enter the mainstream and based on this, predict the leading solutions with clear justifications. This will allow us also to forecast which new ABD functions are most likely to make the transition from premium to mainstream.
As solid-state lighting adoption moves from bulb socket replacement to lighting system engineering, luminaire manufacturers are beginning to actualize far greater cost savings through luminaire optimization rather than the simplistic process of component cost pareto management. Indeed, there are an increasing number of applications in which we see major shifts in the value chain in terms of increasing the L1 (LED) and L2 (LED array on PCB) value. The L1 value increase stems from a number of factors ranging from simply higher performing LEDs reducing the LED count, to L1 innovation such as high voltage LEDs, optimizing driver efficiency or to the use of high luminance LEDs enabling compact optics, allowing not only more design freedom but also cost reduction through space and weight savings. The L2 value increase is realized predominantly through increasing L2 performance with the use of algorithms that optimize L1 selection and placement and/or through L2 integration of drivers, control electronics, sensors, secondary lens and/or environmental protection, which is also initiating level collapse in the value chain. In this paper we will present the L1 and L2 innovations that are enabling this disruption as well as provide examples of fixture/luminaire level benefits.
High power LEDs were introduced in automotive headlights in 2006-2007, for example as full LED headlights in the
Audi R8 or low beam in Lexus. Since then, LED headlighting has become established in premium and volume
automotive segments and beginning to enable new compact form factors such as distributed low beam and new functions
such as adaptive driving beam. New generations of highly versatile high power LEDs are emerging to meet these
In this paper, we will detail ongoing advances in LED technology that enable revolutionary styling, performance and
adaptive control in automotive headlights. As the standards which govern the necessary lumens on the road are well
established, increasing luminance enables not only more design freedom but also headlight cost reduction with space and
weight saving through more compact optics. Adaptive headlighting is based on LED pixelation and requires high
contrast, high luminance, smaller LEDs with high-packing density for pixelated Matrix Lighting sources. Matrix
applications require an extremely tight tolerance on not only the X, Y placement accuracy, but also on the Z height of the
LEDs given the precision optics used to image the LEDs onto the road. A new generation of chip scale packaged (CSP)
LEDs based on Wafer Level Packaging (WLP) have been developed to meet these needs, offering a form factor less than
20% increase over the LED emitter surface footprint. These miniature LEDs are surface mount devices compatible with
automated tools for L2 board direct attach (without the need for an interposer or L1 substrate), meeting the high position
accuracy as well as the optical and thermal performance. To illustrate the versatility of the CSP LEDs, we will show the
results of, firstly, a reflector-based distributed low beam using multiple individual cavities each with only 20mm height
and secondly 3x4 to 3x28 Matrix arrays for adaptive full beam. Also a few key trends in rear lighting and impact on LED
light source technology are discussed.
Planar optics have become the leading technology for DWDM applications, due to its high performance and low
manufacturing costs enabled by wafer scale processing. A powerful new design tool has been successfully applied to
Planar Lightwave Circuit (PLC) design and fabrication, enabling rapid design information turns, mask and process error
correction, and higher final device yields. We also present a new wideband AWG design that permits a low-ripple
passband shape over a larger range of the DWDM spectrum. Combined with state-of-the-art semiconductor fabrication
techniques, these new designs and methodologies have enabled a new generation of high-performance, high-yield PLC-based
Reconfigurable Optical Add-Drop Modules (ROADM's). Optical data from a representative sample of almost 200
ROADM modules is presented, showing a tight statistical distribution of wide passband, low ripple, low insertion loss,
and low polarization dependent loss devices.
The Advanced Silicon Etch (ASE<SUP>R</SUP>) process has been used for silicon substrate etching for the manufacture of SCALPEL<SUP>R</SUP> (SCattering using Angular Limitation Projection E-beam Lithography) masks. The current SCALPEL<SUP>R</SUP> mask fabrication process uses an aqueous solution of KOH to etch the membrane support struts in 100 mm diameter, <100> crystalline silicon wafers. This technique is undesirable for the manufacture of large diameter masks with thicker substrates, as it limits the maximum printable die size. Inductively coupled plasma (ICP) etching, using the ASE<SUP>R</SUP> process, provides the only alternative etch technique. This gives support struts with vertical profiles, yielding a higher printable area than with wet etching, and is ideal for etching the substrates of large diameter masks. In addition to this, and to the benefits of dry over wet etching, the ASE<SUP>R</SUP> process allows the use of wafers of any crystal orientation and gives greater flexibility in pattern placement and geometry. This paper presents process optimization data based on 200 mm diameter wafers, using a system designed specifically for this application. The key aspects of this work have focused on etch rate, CD control and uniformity enhancement. Etch rate determines the economic feasibility of this approach, particularly with etch depths of approximately 750 micrometer. Uniform etching is required to minimize the time to clear the membranes, and the CD tolerances must be met so that structural integrity is maintained. The large exposed silicon areas, (> 40% global and > 80% local), the macro loading effects caused by the edge of the pattern, and the need for near vertical strut profile, make these requirements more difficult to achieve. Etch rate and uniformity achieved, exceed the minimum specification of > 2 micrometer/min and < +/- 6% respectively.
High density plasmas are beginning to dominate the market for advanced anisotropic silicon etching for MEMS applications. This paper looks at the reasons behind this dominance for high etch rate, deep anisotropic etching. A discussion of anisotropic etch mechanisms highlights the need for sidewall passivation to meet these requirements. Results are presented of a novel room temperature advanced silicon etch process: >= 2 micrometers /min; >= 70:1 selectivity to resist (and >= 150:1 to oxide); up to 30:1 aspect ratio; 500 micrometers depth capability; using a non-toxic, non-corrosive environmentally acceptable fluorine-based chemistry.