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Surface Mount Technology (SMT) and Tape Automated Bonding (TAB)
Published in Jack Arabian, Computer Integrated Electronics Manufacturing and Testing, 2020
Before excising, however, the interconnection pattern on the tape must be tested. Past the outer lead window or annulus, the circuit pattern radiates outward to test pads which are used to probe-test and verify the electrical integrity of the created interconnection leads. This test can be done on the continuous tape (known as “reel-to-reel testing”) (see below), or each pattern can be cut and mounted on a temporary carrier and/or a socket (see the section entitled “Test Considerations for TAB”). Other operations such as thermal and burn-in tests, I LB, or other handling can be performed while the carrier is attached. The final step is the attachment of the interconnection circuit and its semiconductor chip to the next interconnection level, such as a PWB. For this, the tape is excised, the leads are “formed,” and the OLB operation is completed. “Lead forming” bends and shapes the leads, usually in a gull-wing or inverted gull-wing outline (see the section entitled “Excising and Lead Forming”). This avoids short-circuiting of an otherwise flat lead on the edge of the next, higher-level substrate.
Component Placement and Soldering
Published in Fred W. Kear, Hybrid Assemblies and Multichip Modules, 2020
When planar leads can be shortened to the gull-wing configuration, which is almost always the case with DIP packages, some of these problems can be mitigated, and placement of the component is greatly simplified. At the same time, the gull-wing lead is still a cantilevered member and can be bent or damaged in handling. Lead straightening or planarity sensing may be necessary before attempting to place these component leads onto the solder paste. Automated pick-and-place equipment may automatically check planarity. Manual assembly may require that the operator pass the leads through a jig to check or adjust their planarity.
Recent Progress and Some Challenges in Thermal Modeling of Electronic Systems
Published in W.J. Minkowycz, E.M. Sparrow, Advances in Numerical Heat Transfer, 2018
As an example of the combined heat transfer effects, consider the transport in a small height-to-width aspect ratio enclosure in Fig. 3, investigated computationally and experimentally by Adams et al. [16, 17], The enclosure dimensions (0.1524 m × 0.1524 m × 0.0318 m on the inside) are representative of a laptop computer. The enclosure is constructed of 0.0127-m-thick plexiglas side walls, a 0.0063-m-thick plexiglas bottom wall, and a 0.0095-m-thick nominally isothermal aluminum top plate. The internal power dissipation is simulated by a three-by-three array of 88-lead plastic quad flat packages (PQFP) containing silicon chip or die, seen in Fig. 4. The 22 package leads on each of the four sides of the chips are in a “gull wing” configuration and are soldered to an epoxy fiberglass printed wiring board (PWB). An air gap of 0.064 m exists between the PWB and bottom plexiglas plate of the enclosure.
Head-up displays assist helicopter pilots landing in degraded visual environments
Published in Theoretical Issues in Ergonomics Science, 2018
Neville A. Stanton, Aaron P. Roberts, Katherine L. Plant, Craig K. Allison, Catherine Harvey
The development of the HUD was part of a larger research project in which the concept was designed with the aid of Cognitive Work Analysis (see Stanton and Plant 2010, 2011; Stanton et al. 2016). The requirement was that the HUD would be capable of assisting the pilot with performing approach and landing in a degraded visual environment. In line with potential future cockpit capabilities, the HUD was developed in a full-colour system with an extended field-of-view (e.g. future windshield displays). To assist with the landing task, the HUD included a flight path vector, which represented the point on the ground that would be hit if velocity was maintained (see Figure 1, #1). Perspective view augmented reality ‘trees’ were located in a fixed position at the landing site starting at 150 ft, providing a visual reference point when landing (see Figure 1, #2). The arrows on the trees moved in accordance to aircraft's altitude, to provide intuitive information concerning height and rate of descent (see Figure 1, #3). The HUD concept was created using GL Studio. A two-way data interface was developed to allow flight data to be transferred from Prepar3D and synchronised symbology to be transferred from GL studio. During the flight conditions with the HUD, the concept was overlaid onto the simulated environment using an open source ghost window application. The HUD contained the following 2D flight instruments: conformal compass, heading readout, airspeed indicator, gull wing horizon line, attitude indicator, vertical speed indicator, air speed indicator, wind direction and strength indicator, ground speed and distance to go (see Figure 1).