• Proceedings of the KSME Conference
• /
• 2001.06a
• /
• pp.90-95
• /
• 2001

Thermo-mechanical and flexural behavior of a wire-bond plastic ball grid array (WB-PBGA) are characterized by high sensitive $moir{\acute{e}}$ interferometry. $Moir{\acute{e}}$ fringe patterns are recorded and analyzed at several various bending loads and temperature steps. At the temperature higher that $100^{\circ}C$, the inelastic deformation in solder balls became more dominant. As a result the bending of the molding compound decreased while temperature increased. The strain results show that the solder ball located at the edge of the chip has largest shear strain by the thermal load while the maximum average shear strain by the bending moment occurs in the end solder. The results also show that $moir{\acute{e}}$ interferometry is a powerful and effective tool in experimental studies of electronic packaging.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 2009.11a
• /
• pp.49-53
• /
• 2009

미래병사를 위한 전투지원 시스템은 여러 가지 디지털 디바이스로 구성되며, 이러한 디바이스들을 적절한 위치에 분산시킴으로써 병사의 전투력을 향상시킬 수 있도록 설계하는 것이 중요하다. 분산 디자인을 위해서는 동작에 따른 인체의 변화를 측정하는 것이 중요하며, 특히 센서를 탑재하기 위해서는 인체 표면의 변화가 세밀히 분석되어야 할 것이다. 본 연구는 Moir$\acute{e}$ 계측방법을 이용하여 동작에 따른 체표변화를 측정함으로써 각종 디지털 디바이스를 탑재할 적절한 신체 부위를 알아내어 기기를 배치함으로써 미래 전장에 적합한 스마트 전투복 디자인을 개발하는 것을 목표로 한다.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.1027-1032
• /
• 2003

Thermo-mechanical behavior of flip-chip plastic ball grid array (FC-PBGA) packages are characterized by high sensitive $Moir{\acute{e}}$ interferometry. $Moir{\acute{e}}$ fringe patterns are recorded and analyzed for several temperatures. Deformation analysis of bending displacements of the packages and average strains in the solder balls for a single-sided package assembly and a double-sided package assembly are presented. The bending displacement of the double-sided package assembly is smaller than that of the single-sided one. The largest of effective strain occurred in the solder ball located at the edge of the chip and its magnitude of the double-sided package assembly is greater than that of single-sided one.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.10 no.1
• /
• pp.117-123
• /
• 2008

When it comes to clothing design, after the mid 20th century some internationally renowned designers began to recognize the pivotal role clothing materials play in attracting the hearts of customers. Accordingly, they started to take advantage of new clothing materials in the sector of clothing design. While the theme of fashionable clothing products shifts from style and color to clothing materials, fashion designers place the quality of materials at the center of clothing designs. Fashion designers also realize that good quality of materials should be used to boost the value of products as well as to satisfy the conditions of creativity, practicality and aesthetics. In particular, as the non-apparel industry in which clothing materials are the most important aspect between fashionable color, silhouette and details is enhancing their attention to develop various materials in order to meet the needs of customers, the fashion industry places a high premium on textile design which is the pinnacle of expressing emotion on clothing materials. In addition, the industry raises awareness of developing more sophisticated and differentiated materials. Our thesis covers the way how to apply $moir{\acute{e}}$ pattern to clothing design on the basis of research. In order to put that research into practical use, we produced textiles which effectively display $moir{\acute{e}}$ pattern. Before this process, we tried to ensure that radial grating created $moir{\acute{e}}$ pattern effects. To this end, the weaving process was applied, depending on whether light can penetrate textiles or not. Then, we manufactured test-products using $moir{\acute{e}}$ pattern.

• Journal of Digital Convergence
• /
• v.17 no.2
• /
• pp.171-176
• /
• 2019

In modern times, many IoT products are being used as all things and devices are connected to the Internet and IoT products become easily accessible through the network. For the convenience of users, IoT products can be remotely operated automatically without manual operation. Various research and development are underway to improve the convenience of users by using IoT products. However, since only the convenience of the users is pursued, in terms of security, there is a serious problem that exposes the user's personal information. This paper has proposed a method to apply $moir{\acute{e}}$ technology to IoT products in order to improve the performance of security, and a method to increase the safety of IoT products using user face authentication based on shadow $moir{\acute{e}}$ as a $moir{\acute{e}}$ phenomenon method, and the projection $moir{\acute{e}}$. When comparing the existing IoT products and IoT products applied with $moir{\acute{e}}$ technology, IoT products applied with $moir{\acute{e}}$ technology are safer in terms of security.

• Journal of the Microelectronics and Packaging Society
• /
• v.24 no.1
• /
• pp.57-65
• /
• 2017

The electronic components in mobile device are composed of electronic chips and various other materials. These components become extremely thin and the constituent materials have different coefficient of thermal expansion, so that considerable warpages occurs easily due to temperature change or external load. Shadow $moir{\acute{e}}$ is non-contact, whole field technique for measuring out-of-plane displacement, but the measurement sensitivity is not less than $50{\mu}m/fringe$, which is not suitable for measuring the warpage of the electronic components. In this paper, we implemented a measurement method with enhanced sensitivity of $25{\mu}m/fringe$ by investigating and optimizing various experimental conditions of the shadow $moir{\acute{e}}$. In addition, four $moir{\acute{e}}$ fringe patterns recorded by the phase shift are processes to obtain a $moir{\acute{e}}$ fringe patterns with a sensitivity four times higher. The measurement technique is applied to small electronic components of a smart phone for measuring warpage with a high sensitivity of $5{\mu}m/fringe$ at room temperature and at the temperature of $100^{\circ}C$.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.1407-1412
• /
• 2003

In MEMS devices, packaging induced stress or stress induced structure deformation become increasing concerns since it directly affects the performance of the device. In this paper, deformation behavior of MEMS gyroscope package subjected to temparature change is investigated using high-sensitivity $Moir{\acute{e}}$ interferometry. Using the real-time $Moir{\acute{e}}$ setup, fringe patterns are recorded and analyzed at several temperatures. Temperature dependent analyses of warpages and extensions/contractions of the package are presented. Linear elastic behavior is documented in the temperature region of room temperature to $125^{\circ}C$. Analysis of the package reveals that global bending occurs due to the mismatch of thermal expansion coefficient between the chip, the molding compond and the PCB.

• Journal of the Optical Society of Korea
• /
• v.12 no.2
• /
• pp.93-97
• /
• 2008

The superposing angle of the viewing zone forming optics and the display panel in the contact type 3 dimensional imaging systems for minimizing $moir{\acute{e}}s$ is found for a rectangular shape pixel with different aspect ratios. The angles are $26.2609^{\circ}$ for square shape pixels and $13.9858^{\circ}$ for the rectangular with aspect ratio 2. These angles result in the $moir{\acute{e}}s$ with the smallest period for the respective aspect ratio. The effectiveness of the angles is also experimentally demonstrated.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.428-431
• /
• 2004

This paper proposes a new 3-D display without glasses using $Moir\acute{e}$ system. It is possible to create a new three-dimensional expression that is different from conventional 3-Dimages. In this study we have geometrically analyzed the process by which moire takes on a three-dimensional property and validated the results of this analysis.

• Journal of Korean Ophthalmic Optics Society
• /
• v.5 no.2
• /
• pp.181-186
• /
• 2000

The setup of the moir$\acute{e}$ deflectometry using the virtual grating was done, so the convergence and divergence of a pencil of ray was determined. The light source was He-Ne laser(3mW). The focal length of the first lens, the second lens being 18 mm, 250 mm respectively was used for the setup of the beam expander. The optics of the moir$\acute{e}$ deflectometry determining the vergence was used a diffraction grating(pitch = $1.6{\mu}m/line$) and a front flat reflection mirror. The effective focal length of the trial lens set was measured and compared with the theoretical value.