Response times and voltages for PDLC light shutters

Wu, Baogang; Erdmann, John H.; Doane, J. William

doi:10.1080/02678298908027783

Cited by 353 publications

(158 citation statements)

References 13 publications

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“…Theoretical models for the device switching (related to the liquid crystal reorientation) process have been presented in order to aid the understanding of such effects. [30,62,129] These publications presented equations that can be used to predict both the field threshold and device switching rates.…”

Section: Bulk Studiesmentioning

confidence: 99%

“…It is now wellknown that highly shaped droplets (i.e., those whose shapes depart significantly from spheroidal) [30,34,61,62,64] exhibit much faster reorientation dynamics. Shown in Figure 9 are the results of studies in which the timescale for orientational relaxation was measured for films containing spheroidal and ellipsoidal droplets.…”

Section: Bulk Studiesmentioning

confidence: 99%

“…[6,36] As a result, the dynamics vary both between and within droplets of differing size, shape, interfacial interactions, and liquid crystal configuration. [30,34,61,62,64] …”

Section: Liquid Crystal Reorientation Dynamicsmentioning

confidence: 99%

See 2 more Smart Citations

Probing the Mesoscopic Chemical and Physical Properties of Polymer-Dispersed Liquid Crystals

2000

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Section: Bulk Studiesmentioning

confidence: 99%

Section: Bulk Studiesmentioning

confidence: 99%

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Probing the Mesoscopic Chemical and Physical Properties of Polymer-Dispersed Liquid Crystals

2000

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“…It is known that the reorientation field scales inversely with droplet size because the small liquid crystal domains produce high free energy of elastic deformations within the liquid crystal [20]. Typical response times of the films are shown in Figure 7, Table 3 and Table 4 for different types of clay and clay contents.…”

Section: Response Timesmentioning

confidence: 99%

Memory effect of polymer dispersed liquid crystal by hybridization with nanoclay

Jeong¹,

Sun²,

Kang³

et al. 2010

Express Polym. Lett.

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Abstract. The electro-optical performances of polymer dispersed liquid crystal (PDLC) were investigated in the presence of organically modified clays. With the addition and increasing amount of modified clay, driving voltage and memory effect, viz. transparent state of the film after the electricity is off simultaneously increased due most likely to the increased viscosity. Among the two types of modifier, 4-(4-aminophenyl) benzonitrile having greater chemical affinity with LC than hexylamine, gave finer dispersion of clay in liquid crystal, greater viscosity, larger driving voltage and response time, and greater memory effect.

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“…Methods have been developed for faster response including polymer-stabilized LC, [1][2][3] polymer-dispersed LC, 4 and π-cells. [5][6][7][8] However, the transition time of all of these devices are still in the range of several milliseconds and not sufficient for the high-frame rates needed for multifield sequential displays.…”

Section: Introductionmentioning

confidence: 99%

Fast-response liquid crystal variable optical retarder and multilevel attenuator

2013

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Abstract. We propose and demonstrate a fast-response liquid crystal (LC) variable optical retarder or attenuator with several transmission levels. The fast-response LC optical device consists of dual π-cells. The device is designed so that the transition between any two states is controlled by the application of an increased voltage level rather than by applying a lower level. This design offers transition times in the range of tens of microseconds between any transmission states. A limitation of the device is that the time between transitions cannot be arbitrarily short and is typically milliseconds. 1 Introduction A fast-response liquid crystal (LC) optical retarder or an attenuator with multilevel transmission is needed for many applications, where LC devices are considered to be too slow [e.g., in the field of optical communications or for field sequential three-dimensional (3-D) displays of the future].The response time of conventional nematic LC devices is usually in the range of milliseconds. Methods have been developed for faster response including polymer-stabilized LC, 1-3 polymer-dispersed LC, 4 and π-cells. 5-8 However, the transition time of all of these devices are still in the range of several milliseconds and not sufficient for the high-frame rates needed for multifield sequential displays.To understand why many previous approaches have not been sufficient in decreasing the response time of LC devices, it is helpful to consider what governs that time. In most LC devices, the director orientation results from the competition between torques exerted by an applied electric field, and the elastic torques resulting from the director are not being uniformly aligned with the surface-imposed orientation. The response time of the device is different for the case of the transition to a more distorted director field with the application of a higher voltage (call this, the voltage-applied transition) than it is to the less distorted director field with the application of a lower voltage (call this, the voltage-removed transition). If we would like to decrease the response time for the first case, an approach is just to apply a higher voltage during the transition, but the response time of the second case is limited by the material properties of the LC material that cannot be chosen at will. Therefore, it is typical that the total response time of a LC device is limited by the time required for transition to the less distorted state when the applied voltage is lowered (or removed).Therefore, it has been the focus of a great deal of research to modify the material properties of LC materials to decrease the response time. But for many applications, the results of this work have not been sufficient.

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Response times and voltages for PDLC light shutters

Cited by 353 publications

References 13 publications

Probing the Mesoscopic Chemical and Physical Properties of Polymer-Dispersed Liquid Crystals

Probing the Mesoscopic Chemical and Physical Properties of Polymer-Dispersed Liquid Crystals

Memory effect of polymer dispersed liquid crystal by hybridization with nanoclay

Fast-response liquid crystal variable optical retarder and multilevel attenuator

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