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Article
Publication date: 1 April 1996

I.P. Hall

The drive towards low unit cost in optoelectronic packaging is assisted by avoiding the need for hermeticity and by the use of simple assembly techniques. Silicone gels

228

Abstract

The drive towards low unit cost in optoelectronic packaging is assisted by avoiding the need for hermeticity and by the use of simple assembly techniques. Silicone gels can solve this problem, provided the reliability meets the application requirements. Extensive lifetest data for semiconductor lasers and PIN photodiodes coated in silicone gels are reported in this paper. Results to date show great promise and promote confidence in the use of these materials for the environmental protection of optoelectronic devices. Apart from silicone gels, light cured resin materials can also offer benefits towards lower cost assembly processes. Tests are reported of the degradation in optical transmission of these resins and also bulk degradation under differing environmental conditions. The use of these polymer materials can play an integral part in low‐cost optoelectronic packaging developments, two specific designs of which — a silicon laser optical bench and a ceramic ferrule co‐axial structure — will be described. Both of these packages take advantage of a passive fibre/device alignment allowed by the use of an expanded beam laser design.

Details

Microelectronics International, vol. 13 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 February 1994

I.P. Hall

The drive towards low unit cost in optoelectronics packaging is assisted by simple, rapid assembly processes, and by avoiding the need for hermeticity. This paper…

Abstract

The drive towards low unit cost in optoelectronics packaging is assisted by simple, rapid assembly processes, and by avoiding the need for hermeticity. This paper discusses the use of visible blue‐light cured resins as an important issue in assembly techniques. Results are also reported on trials of silicone gels as a means to produce hermetic equivalence performance in optoelectronic (O‐E) components and associated electronics. Photodiodes coated in these gels could be expected to have a service life of >60 years and results for coated lasers are encouraging with degradations of 4%/1000 h of damp heat stress, while GaAs ICs showed no degradation. The potential of these technologies has made possible the fabrication of a simple photodiode mount with coupling efficiencies approaching 100%. Low cost laser assembly has also been investigated. To demonstrate the feasibility of these technologies an O‐E transceiver module has been produced.

Details

Microelectronics International, vol. 11 no. 2
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 1 February 1976

W. MacLeod Ross

In this paper a review is given of the more commonly employed organic polymers for coating and embedment of electronic modules. Following discussion of the basic types and…

Abstract

In this paper a review is given of the more commonly employed organic polymers for coating and embedment of electronic modules. Following discussion of the basic types and their properties, problems arising from emission of volatiles from encapsulants are outlined and the importance of considering these in early design stages is stressed.

Details

Circuit World, vol. 2 no. 3
Type: Research Article
ISSN: 0305-6120

Content available
Article
Publication date: 3 July 2009

34

Abstract

Details

Pigment & Resin Technology, vol. 38 no. 4
Type: Research Article
ISSN: 0369-9420

Article
Publication date: 1 January 1991

D. Ročak, M. Kosec and F. Jan

An evaluation of some silicone and epoxy materials for primary chip and top coatings on hybrid circuits and of their relative merits on the basis of humidity and…

Abstract

An evaluation of some silicone and epoxy materials for primary chip and top coatings on hybrid circuits and of their relative merits on the basis of humidity and temperature cycling is presented.

Details

Microelectronics International, vol. 8 no. 1
Type: Research Article
ISSN: 1356-5362

Article
Publication date: 1 June 2005

S.M. Tavakoli, D.A. Pullen and S.B. Dunkerton

Aims to review polymeric materials used as adhesives and the related bonding procedures applicable in the medical industry.

1744

Abstract

Purpose

Aims to review polymeric materials used as adhesives and the related bonding procedures applicable in the medical industry.

Design/methodology/approach

The main types of polymeric materials used as adhesives are described. Details and the main points of the adhesive bonding processes are also described with comments on their adaptability to automated assembly. Finally, typical examples of the use of adhesives in medical device applications are provided.

Research limitations/implications

Review paper with examples of applications of adhesives in assembly of medical materials and devices.

Practical implications

The appropriate selection of adhesive types and bonding parameters are critical for successful application of this technology in joining medical materials. Most currently available medical grade adhesives are only suitable for short‐term (<30 days) implantable application. The users must ensure that the properties of the selected adhesives, particularly the relevant biocompatibility and toxicity data are available and fully comply with any specific medical device application and regulation.

Originality/value

Although this is a general review paper, it contains information about new materials and processing techniques applied in successful application of adhesive bonding technology in medical devices. The information provided is expected to be of significant benefit to material scientists and design engineers evaluating and identifying suitable joining techniques for the assembly of medical devices.

Details

Assembly Automation, vol. 25 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 1 May 2006

Sung Yi, Sang Kyoo Park and Kiat Choon Teo

To provide a design guideline for an automotive electronic module in order to improve its reliability in elevated environmental environments as well as in vibration environments.

Abstract

Purpose

To provide a design guideline for an automotive electronic module in order to improve its reliability in elevated environmental environments as well as in vibration environments.

Design/methodology/approach

Wire looping profiles, gel heights, and effects of mechanical vibration on aluminium wire bond failures are studied. Natural frequencies of various wire profiles are evaluated and effects of gel heights on reliability of products are studied using stochastic finite element analyses. The frequency dependent properties of silicone gels used in electronic modules are characterized by the corn and plate test. An experiment was also conducted in order to confirm numerical results.

Findings

The present study shows that the gel plays an important role in wire bond failures and reliability of the product. The gel reduces the amplitude of vibration of electronic modules due to its damping characteristics. However, both analytic and experimental results indicate that the gel imposes extra weight on the wires and may induce stresses on heels.

Research limitations/implications

In the future study, it is suggested that other gel materials should be studied since the properties of gel strongly depend on the frequency which will affect the fatigue behavior of bonding wires.

Practical implications

The findings can be used as general design guidelines for wire bonding for automotive electronic modules.

Originality/value

The results will be very useful to design bonding wires for automotive electronic modules.

Details

Microelectronics International, vol. 23 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 1 February 1949

A.E WILLIAMS

Silicones were developed by the Dow Corning Corporation and have been manufactured in the U.S.A. for several years. More recently they have become available in Great…

Abstract

Silicones were developed by the Dow Corning Corporation and have been manufactured in the U.S.A. for several years. More recently they have become available in Great Britain. One of the several uses is in the sphere of lubrication. Experience with these relatively new materials shows that they possess a combination of properties which go a long way in eliminating some of the problems encountered by the lubrication engineer. In this article, MR. WILLIAMS, a consulting chemist, who has been responsible for considerable original research on oils, describes some of the advantages and disadvantages that these new materials possess and points out that their particularly good viscosity index, low pour point and excellent chemical stability will make their adoption for various lubricating purposes increasingly inviting.

Details

Industrial Lubrication and Tribology, vol. 1 no. 2
Type: Research Article
ISSN: 0036-8792

Article
Publication date: 13 June 2016

M. Grujicic, S. Ramaswami, J. S. Snipes, R. Yavari and P. Dudt

The design of the Advanced Combat Helmet (ACH) currently in use was optimized by its designers in order to attain maximum protection against ballistic impacts (fragments…

Abstract

Purpose

The design of the Advanced Combat Helmet (ACH) currently in use was optimized by its designers in order to attain maximum protection against ballistic impacts (fragments, shrapnel, etc.) and hard-surface/head collisions. Since traumatic brain injury experienced by a significant fraction of the soldiers returning from the recent conflicts is associated with their exposure to blast, the ACH should be redesigned in order to provide the necessary level of protection against blast loads. The paper aims to discuss this issue.

Design/methodology/approach

In the present work, an augmentation of the ACH for improved blast protection is considered. This augmentation includes the use of a polyurea (a nano-segregated elastomeric copolymer) based ACH external coating. To demonstrate the efficacy of this approach, blast experiments are carried out on instrumented head-mannequins (without protection, protected using a standard ACH, and protected using an ACH augmented by a polyurea explosive-resistant coating (ERC)). These experimental efforts are complemented with the appropriate combined Eulerian/Lagrangian transient non-linear dynamics computational fluid/solid interaction finite-element analysis.

Findings

The results obtained clearly demonstrated that the use of an ERC on an ACH affects (generally in a beneficial way) head-mannequin dynamic loading and kinematic response as quantified by the intracranial pressure, impulse, acceleration and jolt.

Originality/value

To the authors’ knowledge, the present work is the first reported combined experimental/computational study of the blast-protection efficacy and the mild traumatic brain-injury mitigation potential of polyurea when used as an external coating on a helmet.

Details

Multidiscipline Modeling in Materials and Structures, vol. 12 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

Article
Publication date: 8 August 2016

Mica Grujicic, S Ramaswami, Jennifer Snipes, Ramin Yavari and Philip Dudt

The purpose of this paper is to optimize the design of the advanced combat helmet (ACH) currently in use, by its designers in order to attain maximum protection against…

Abstract

Purpose

The purpose of this paper is to optimize the design of the advanced combat helmet (ACH) currently in use, by its designers in order to attain maximum protection against ballistic impacts (fragments, shrapnel, etc.) and hard-surface/head collisions. Since traumatic brain injury experienced by a significant fraction of the soldiers returning from the recent conflicts is associated with their exposure to blast, the ACH should be redesigned in order to provide the necessary level of protection against blast loads. In the present work, augmentations of the ACH for improved blast protections are considered. These augmentations include the use of a polyurea (a nano-segregated elastomeric copolymer)-based ACH external coating/internal lining.

Design/methodology/approach

To demonstrate the efficacy of this approach, instrumented (unprotected, standard-ACH-protected, and augmented-ACH-protected) head-mannequin blast experiments are carried out. These experimental efforts are complemented with the appropriate combined Eulerian/Lagrangian transient non-linear dynamics computational fluid/solid interaction analysis.

Findings

The results obtained indicated that: when the extent of peak over-pressure reduction is used as a measure of the blast-mitigation effectiveness, polyurea-based augmentations do not noticeably improve, and sometimes slightly worsen, the performance of the standard ACH; when the extent of specific impulse reduction is used as a measure of the blast-mitigation effectiveness, application of the polyurea external coating to the standard ACH improves the blast-mitigation effectiveness of the helmet, particularly at shorter values of the charge-detonation standoff distance (SOD). At longer SODs, the effects of the polyurea-based ACH augmentations on the blast-mitigation efficacy of the standard ACH are inconclusive; and the use of the standard ACH significantly lowers the accelerations experienced by the skull and the intracranial matter. As far as the polyurea-based augmentations are concerned, only the internal lining at shorter SODs appears to yield additional reductions in the head accelerations.

Originality/value

To the authors’ knowledge, the present work contains the first report of a combined experimental/computational study addressing the problem of blast-mitigation by polyurea-based augmentation of ACH.

Details

International Journal of Structural Integrity, vol. 7 no. 4
Type: Research Article
ISSN: 1757-9864

Keywords

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