The strength of glass panels is critical for the performance of touch-screen displays, especially in regards to how it responds to impact or drop. Insufficient drop testing performance can be related to two parameters: fracture strength and flaw size. The fracture strength of touch screen panels, everything else being equal, is primarily driven by the degree of strengthening performed on the surface of the glass. Glass of less than 1/8th inch thickness for touch screen panel applications tends to require a chemical strengthening process as thermal quenching can induce warpage in these thinner glass sheets. Chemical strengthening is performed through an ion-exchange mechanism, typically in a potassium-based solution. The larger potassium ion (r+ = 0.133 nm) substitutes for the smaller sodium ion (r+ = 0.098 nm), inducing a volumetric increase and creating residual compressive stresses at the outer layer of the glass (see Figure 1).
A very smart person once noted that all the problems in the world seem to occur at the boundary between one entity and another. While this analogy might be slightly overkill, it does place a spotlight on one of the most common problems in electronic and electro-mechanical design: board- to-board connections.
Board-to-board connections can be complex problems to solve, as they need to be responsive to a number of product requirements. Most critical of these are typically, cost, dimensional limitations, and the ability to perform rework. These problems can be solved, but designers are often not aware of the variations of board-to-board connections that are available and, due to competing requirements, can sometimes select solutions that satisfy some, but not all of the needs of the manufacturing process and the customer.
In this white paper, DfR will provide a brief overview of some of the more common board-to- board connections available and the process for selecting the optimum solution for your product design.
Counterfeit components have been defined as a growing concern in recent years as demand increases for reducing costs. A counterfeit is any item that is not as it is represented with the intention to deceive its buyer or user. The misrepresentation is often driven by the known presence of defects or other inadequacies in regards to performance. Whether it is used for a commercial, medical or military application, a counterfeit component could cause catastrophic failure at a critical moment.
The market for long life electronics, based on commercial off the shelf (COTS) parts, such as those used in medical, military, commercial depot repair, or long term use applications (e.g. street and traffic lights, photovoltaic systems), seems to create a perfect scenario for counterfeiters. With these products, components wear out and need to be replaced long before the overall product fails. The availability of these devices can be derived in many ways. For example, a typical manufacturer may render a component obsolete by changing the design, changing the functionality, or simply discontinuing manufacture. Also, the parts that are available after a design has been discontinued are often distributed by brokers who have very little control over the source or supply. And finally, as demand and price increase, the likelihood of counterfeits also increases.
The purpose of a cyclic THB test is to assess the ability of a product to operate reliably under condensing conditions (dew point). The rationale for more than one cycle is based on observations that repeated applications of temporary condensation events can lead to wearout type behavior ( > 1) over time. Initial condensation events “weaken” the circuit by inducing dissolution of conductor material (in this case, copper). The elevated presence of these metals eventually is sufficient to induce electrochemical migration between insulated conductors.
Eutectic AuSn solder is increasingly used in high reliability and/or high temperature applications where conventional SnPb and Pb-free solders exhibit insufficient strength, creep resistance, and other issues. These applications include hybrid microelectronics (particularly flip chips), MEMS, optical switches, LEDs, laser diodes, RF devices, and hermetic packaging for commercial, industrial, military, and telecommunications applications. For most of these applications, AuSn provides the additional benefit of not requiring flux during reflow, significantly reducing the potential for contamination and pad corrosion. However, the materials and processing considerations are substantially different than for conventional solders. Many companies struggle with issues such as poor solder flow, excessive void formation, variable reflow temperature (arising from off-eutectic compositions), heterogeneous phase distribution, and others, all contributing to development delays, process yield loss, and field reliability issues. This paper reviews the critical issues in material and process selection, as well as long term diffusion and mechanical stability.
We’ve all had that moment of panic when our beverage of choice, possibly sitting a little too close to the computer, gets bumped by a careless, quick movement or an unnoticing coworker passing by. Have you ever wondered, “will this just be a pain to clean or will it actually damage my computer (or keyboard, mouse, etc.)?” If the computer is on, this has everything to do with a possible short. A short is only possible if your drink is conductive. So, how conductive do you think drinks are? DfR Solutions has taken conductivity measurements of a sizable number of common drinks using a graduated cylinder, a conductivity meter, and a dip cell.
One of the greatest concerns during this transition to Pb‐free electronics, and therefore Pb‐free components, has been the supposed rapid and widespread adoption of pure tin plating as the solderability plating of choice. A number of questionable surveys have driven this belief, with some promoting that ‘pure’ tin has captured 75% or more of the market.
Optical transceivers & transponders are an integral part of fiber optic networks for data communication and Ethernet applications. By definition, they are co-packaged transmitters (Tx) and receivers (Rx) along with control electronics; transceivers and transponders have serial and parallel electrical interfaces, respectively. The Tx subcomponents are typically fixed wavelength, and offered for each coarse or dense wavelength division multiplexing (CWDM or DWDM) channel, so that multiple transceivers can be operated simultaneously on a single optical fiber. However, in the last 10 years, tunable transponders have become available, capable of operating on each of 100-200 channels centered on the telecom wavelengths of 1310 and 1550 nm.