Hygromechanical Analysis of Liquid Crystal Display Panels

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Toru Ikeda ◽  
Tomonori Mizutani ◽  
Kiyoshi Miyake ◽  
Noriyuki Miyazaki
Keyword(s):  
Boundary Layer ◽  
Liquid Crystal ◽  
Numerical Analysis ◽  
Diffusion Coefficients ◽  
Liquid Crystal Display ◽  
Fem Analysis ◽  
Contact Condition ◽  
Henry's Law ◽  
Henry’S Law ◽  
The Difference

Liquid crystal displays (LCDs) are getting larger, and the homogeneity of an LCD panel is becoming very important for the quality of the display. Inhomogeneity in an LCD panel can be caused by inhomogeneity of its materials and the defective production process, warpage of the panel due to changes in the temperature and humidity, and so on. In this study, we developed a scheme of hygromechanical analysis to reduce the warpage of an LCD. First, we measured the diffusion coefficients and Henry's law coefficients of the respective components of an LCD using a thermogravimetric analyzer (TGA) under controlled humidity. We then measured the coefficients of moisture expansion (CME) of the components using a humidity-controlled thermomechanical analyzer (TMA). We analyzed the hygromechanical deformations of the respective components, a polarizing plate and an LCD panel using the finite element method (FEM) with measured diffusion coefficients, Henry's law coefficients and the CMEs of the respective components. The analyzed deformations of the respective components corresponded quantitatively with the deformations measured experimentally. However, the analyzed deformation of the polarizing plate did not correspond with the measured deformation perfectly. A polarizing plate is made by sandwiching a polarizer between two sheets of protection film. We ignored the effect of the thin boundary layer between the polarizer and its protecting film in this analysis, and the effect of this boundary layer on the diffusion of moisture may have caused the difference between the analysis and the measurement. The expected warpage of the analyzed LCD corresponded qualitatively with the measured warpage. However, the numerical analyzed strains near the edge of the LCD panel strongly shifted to the compression side compared to the experimental measured strains. A possible reason for this shift was the difference in the boundary condition at the edge of the LCD panel between the numerical analysis and the experimental measurement. The actual edge of the LCD panel was fastened by a bezel, and the contact condition between the LCD panel and the bezel was ambiguous. To perform a quantitative analysis, we will need to investigate the contact condition between the LCD panel and the bezel and introduce it to the numerical analysis. This is left for a future study. We qualitatively investigated the warpage of LCDs with two types of protecting film and different directions of polarizing plates using the developed technique of FEM analysis.

Hygro-Mechanical Analysis of LCD Panels

2009 ◽  
Author(s):  
Toru Ikeda ◽  
Tomonori Mizutani ◽  
Noriyuki Miyazaki
Keyword(s):  
Boundary Layer ◽  
Diffusion Coefficients ◽  
Fem Analysis ◽  
Mechanical Analysis ◽  
Protective Film ◽  
Henry's Law ◽  
Pressure Sensitive Adhesive ◽  
Moisture Expansion ◽  
Henry’S Law ◽  
Glass Plates

Liquid crystal displays (LCDs) are getting larger, and the homogeneity of an LCD panel is becoming very important for the quality of the display. Inhomogeneity in an LCD panel can be caused by inhomogeneity of its materials and the defective production process, warpage of the panel due to changes in the temperature and humidity, and so on. In this study, we developed a scheme of hygro-mechanical analysis to reduce the warpage of an LCD. First, we measured the diffusion coefficients and Henry’s law coefficients of the respective components of an LCD using a thermo-gravimetric analyzer (TGA) under controlled humidity. We then measured the coefficients of moisture expansion (CME) of the componenets using a humidity-controlled thermo-mechanical analyzer (TMA). We analyzed the hygro-mechanical deformations of the respective components, a polarizing plate and an LCD panel using the finite element method (FEM) with measured diffusion coefficients, Henry’s law coefficients and the CMEs of the respective components. The analyzed deformations of the respective components corresponded quantitatively with the deformations measured experimentally. However, the analyzed deformation of the polarizing plate did not correspond with the measured deformation perfectly. A polarizing plate is made by sandwiching a polarizer by two sheets of protective film; the effect of the thin boundary layer between the polarizer and its protecting film was ignored in this analysis. The effect of this boundary layer on the diffusion of moisture may have caused the difference between the analysis and the measurement. The expected warpage of the analyzed LCD corresponded qualitatively with the measured warpage. In LCD panels, glass plates and polarizing plates are bonded using pressure-sensitive adhesive. Slippage between the glass plates and the polarizing plates may occur during the deformation of an LCD. We investigated the warpage of LCDs with two types of protecting film and different directions of polarizing plates using the developed technique of FEM analysis.

Experiments in switching the bistable boundary layer liquid crystal display by the application of dc

1984 ◽  
Vol 55 (10) ◽  
pp. 3846-3855 ◽  
Author(s):  
R. N. Thurston ◽  
G. D. Boyd ◽  
Donna Cowell Senft
Keyword(s):  
Boundary Layer ◽  
Liquid Crystal ◽  
Liquid Crystal Display

Multiplexing the bistable boundary layer liquid crystal display

1984 ◽  
Vol 44 (7) ◽  
pp. 655-657 ◽  
Author(s):  
Donna Cowell Senft ◽  
Gary D. Boyd ◽  
R. N. Thurston
Keyword(s):  
Boundary Layer ◽  
Liquid Crystal ◽  
Liquid Crystal Display

Discovery of dc switching of a bistable boundary layer liquid crystal display

1983 ◽  
Vol 43 (4) ◽  
pp. 342-344 ◽  
Author(s):  
Robert B. Meyer ◽  
R. N. Thurston
Keyword(s):  
Boundary Layer ◽  
Liquid Crystal ◽  
Liquid Crystal Display

scholarly journals Backward Spectral Characterization of Liquid Crystal Display Based on Forward Spectral Characterization

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Jian-qing Zhang ◽  
Fang Cai ◽  
Xiao-ying Shen ◽  
Zhen Liu ◽  
Ming Zhu
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystal Display ◽  
Color Space ◽  
Spectral Characterization ◽  
Spectral Radiation ◽  
Digital Input ◽  
Space Transformation ◽  
Color Space Transformation ◽  
Characterization Model ◽  
The Difference

A backward spectral characterization for Liquid Crystal Display by the use of rule for the maximum peak of spectral radiation curves changing with the digital input values is proposed; this new model is developed based on forward spectral characterization. It deals with estimation ofRGBused as input to the digital display from known spectral radiation curves. We first investigate the rule for the peak of spectral radiation curves changing with the digital input values of primaries; then the initial digital inputRGBare calculated based on that rule using the known spectral radiation curvesρ0. Third,RGBare inputted into forward spectral characterization model and the corresponding spectral radiation curvesρ1are predicted. Last,RGBare modified according to the difference between predictedρ1and knownρ0, until this difference satisfied the prediction accuracy of the inverse characterization model. The inverse model has the advantage of using the same model for both forward and inverse color space transformation. This improves the accuracy of the color space transformation and reduces the source of errors. Results for 3 devices are shown and discussed; the accuracy of this model is considered sufficient for many applications.

Sorption and surface diffusion in porous glass

1952 ◽  
Vol 213 (1113) ◽  
pp. 250-265 ◽  
Keyword(s):  
Surface Diffusion ◽  
Porous Glass ◽  
Diffusion Coefficients ◽  
Hysteresis Loops ◽  
Transient State ◽  
Substantial Contribution ◽  
Henry's Law ◽  
Henry’S Law ◽  
Type Iv ◽  
Adsorbed Films

Sorption, gas-phase diffusion in the region of molecular streaming, and surface diffusion in very dilute adsorbed films have been studied quantitatively for a number of gases in membranes of porous glass. The sorption of oxygen, nitrogen, argon, sulphur dioxide and ammonia near their liquefying temperatures resulted in type IV isotherms with very characteristic hysteresis loops. From the isotherms porosity, surface area and mean pore radius were evaluated. Heats of sorption, Δ H , have been obtained in very dilute adsorbed films and in films where v/v m approaches or exceeds one. These heats showed the porous glass to be an energetically non-uniform sorbing surface. The Henry’s law region of sorption was studied and Henry’s law sorption constants evaluated at 273, 290, 323 and 343° K for the most dilute adsorbed films of oxygen, nitrogen, argon, krypton, methane and ethane. Nearly all this information is essential for measurements of surface diffusion by the transient state method of Barrer & Grove (1951). The micropore structure was so fine that non-sorbed gases diffused within the porous glass only by molecular streaming at pressures up to half an atmosphere or more. Effects of sorption upon this diffusion were inappreciable for helium, neon and possibly hydrogen; for oxygen, nitrogen, argon, krypton, methane and ethane the influence of sorption upon timelags and diffusion coefficients became progressively more marked. In the steady state of flow there was little evidence of surface diffusion when, in the most dilute adsorbed films, Henry’s law is obeyed. On the other hand, in the transient state of flow, surface diffusion makes a substantial contribution to flow. Reasons are given for the difference in the extent to which surface mobility can be detected in the two states of flow. Consistent values of the surface diffusion coefficients, D 8 , were obtained for oxygen, nitrogen, argon, krypton, methane and ethane. These values of D 8 were compatible with the Arrheniusequation D 8 = D 0 exp ( – E / RT ) over the temperature range of 273 to 343° K investigated. The ratio of E to Δ H for very dilute adsorbed films lay between 0·5 and 0·6, and should in order of magnitude be characteristic of a heterogeneous sorbing surface. The numerical values of D 8 have been compared with D for liquids, and analyzed in terms of entropy and energy of activation.

Sistem Kontrol Pengisian Air Otomatis Dengan Dua Sumber Suplai Berbasis Mikrokontroler (ATmega 8535)

2016 ◽  
Vol 1 (2) ◽  
pp. 84 ◽  
Author(s):  
Sumardi Sumardi ◽  
Muhammad Nur Anggoro
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystal Display

Sistem kontrol pengisian air otomatis dengan dua sumber suplai berbasis mikrokontroler merupakan sebuah sistem yang dapat digunakan untuk mengendalikan level air pada sebuah bak penampungan secara otomatis. Bahan dan alat yang digunakan dalam sistem kontrol berupa mikrokontroler ATmega 8535, sensor air, downloader DI-USB AVR ISP V2/DI-USB to Serial TTL, liquid crystal display, transisor, resistor, pompa air, adaptor 12 volt dc, saklar, dan program editor code vision avr. Metode yang digunakan dalam pembuatan sistem kontrol pengisian air otomatis ini adalah melakukan percobaan dan ujicoba peralatan secara langsung. Sistem kontrol ini bekerja dalam dua kondisi yaitu ketika air dalam bak penampungan melewati batas bawah maka bak penampungan akan terisi secara otomatis dan ketika telah mencapai batas atas yang ditentukan maka suplai air ke bak penampungan akan berhenti, selanjutnya ditambah pengaturan dari dua buah sumber air sebagai suplai yang akan bekerja sesuai dengan prioritasnya. Proses tersebut dilakukan oleh sensor bagian input yang berupa sensor air pada masukan sumber air yang kemudian diproses oleh mikrokontroler terprogram. Hasil percobaan menunjukkan sensor air berhasil memberikan logika Low atau High pada keluarannya sebagai fungsinya untuk memberikan sinyal masukan pada port mikrokontrol. Pada kondisi high, sensor air mampu memberikan nilai tegangan 4,89 Volt DC untuk digunakan sebagai masukan mikrokontroler. Dan pada kondisi low, sensor air mampu memberikan nilai tegangan 0,11 Volt dc sebagai masukan mikrokontroler ketika elektroda tehubung dengan common oleh media air. Driver Masukan terbukti dapat digunakan untuk menggendalikan kerja dari motor pompa 220 V AC dan lampu indikator 12 V DC. Hasil yang dari sistem kontrol pengisian air ini adalah terjadinya pengurangan kerugian yang ditimbulkan karena masalah ketersediaan air dan juga mempermudah kegiatan dalam pengendalian ketersediaan air. Kata kunci : Sistem kontrol, pengisan air otomatis, mikrokontroler, sensor air.

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