Design Talk: Year in Review
Increasing Ruggedization and Viewability in Mobile Displays
By William S. Bandel, DuPont Display Enhancements, www.vertak.dupont.com
When designing displays for mobile applications it’s often a balancing act between increasing ruggedization and keeping the product’s weight down. These two seemingly opposite ideas can be solved by optically bonding substrates to the LCD front surface thereby eliminating the air gap which increases ruggedization without adding weight. Additional benefits resulting from the removal of the air gap include: the elimination of condensation and fogging, better viewing experience, thinner display designs and the reduction of parallax issues especially in tablet PC applications
Another concern for mobile displays is outdoor readability. In displays using a non-bonded cover glass, the ambient light reflects off three interfaces resulting in as much as 13.5% reflectance. One approach to increasing viewability is to use coverplates treated with anti-reflective (AR) coatings. However this solution only minimizes light reflectivity and doesn’t address the need for greater display contrast. Instead, you can optically bond the AR-coated substrate directly to the LCD eliminating the air gap between the two reflective surfaces of the cover glass and the LCD allowing great reductions in reflectance and reducing the number of anti-reflective treatments needed. With optical bonding, the contrast ratio can increase by as much as 400% verses a non-bonded display.
For these reasons, optical bonding should be considered when designing displays that are going into high-performance consumer or industrial mobile applications. Since DuPont first developed DuPont™ Vertak™ direct bonding technology for optical bonding, it has been used extensively in marine electronics, medical applications, commercial avionics, notebook and tablet PCs, and touch screen devices. Vertak™ technology has continued to withstand the highly-demanding environmental challenges faced by these displays supporting stable performance under extreme temperatures and altitudes by increasing outdoor readability up to 400%, enhancing impact and scratch resistance by 300%, improving durability to withstand shock and vibration, providing a barrier to stains, dirt, moisture and scratches, and even enabling thinner and lighter display designs.
Timing: Oscillators in a Modern Circuit
By: Randall Restle, Technical Marketing Manager, Newark, www.newark.com
Timing is critical to the operation of a modern digital system. A variety of techniques and solutions may be used to create a clock source, but whether the required frequency is a few kilohertz or over 100MHz, designers must consider factors including cost, power consumption, footprint, stability over temperature and supply voltage, and generated noise.
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