A newly patterned electrode is designed for a dielectric liquid lens. The electrode has a radial interdigitated structure which can provide a symmetrical-nonuniform fringing field. This electric field can effectively deform the shape of a dielectric liquid droplet in radial direction, causing the focal length of the liquid droplet to change. For a lens using glycerol as the droplet and optical oil (SL-5267) as the surrounding medium, its focal length (f) can be tuned in the range of ∼ −8.28 ≦̸ f ≦̸ ∼ −4.4 mm, when the applied voltage is changed from 0 to 120 Vrms. In contrast to previous approaches, the liquid lens with radial interdigitated electrode has the advantages of scalable aperture size, wide variability of focal length, and good optical characteristics. Moreover, the driving voltage is insensitive to the size of the droplet.

Real-world scenes usually contain a set of cluttered and yet contextually related objects. Here we used fMRI to investigate where and how contextually related multiple objects were represented in the human ventral visual pathway. Specifically, we measured the responses in face-selective and body-selective regions along the ventral pathway when faces and bodies were presented either simultaneously or in isolation. We found that, in the posterior regions, the response for the face and body pair was the weighted average response for faces and bodies presented in isolation. In contrast, the anterior regions encoded the face and body pair in a mutually facilitative fashion, with the response for the pair significantly higher than that for its constituent objects. Furthermore, in the right fusiform face area, the face and body pair was represented as one inseparable object, possibly to reduce perceptual load and increase representation efficiency. Therefore, our study suggests that the visual system uses a hierarchical representation scheme to process multiple objects in natural scenes: the average mechanism in posterior regions helps retaining information of individual objects in clutter, whereas the nonaverage mechanism in the anterior regions uses the contextual information to optimize the representation for multiple objects.

In this work, an adaptive liquid lens using a novel transparent electrically responsive fluid, dibutyl adipate (DBA), is demonstrated. The DBA liquid lens with a hemispherical plano-convex shape can change its curvature according to the application of various input voltages. More specifically, when an external direct current (DC) electric field is applied to the DBA liquid, the charges that are injected from the cathode move along with the DBA molecules toward the anode and accumulate on the surface of the anode. When the DC electric field is removed, the shape of the DBA liquid is recovered to its original state. This electrostatic force induces the deformation of the DBA liquid lens within a concentric annular anode electrode. In addition, the focal length of our system is increased from a value of approximately 7.5 mm to 13.1 mm when the voltage is changed from 0 to 100 V. Interestingly, the resolution of our DBA liquid lens can reach a value of ∼28.5 lp/mm. The proposed DBA liquid lens exhibits high optical transmittance (∼95%), good thermal stability (20–100°C), simple structure, and an excellent imaging property, which implies that the DBA liquid is a promising candidate for fabricating novel adaptive liquid lenses.