## 5 Applications and Challenges
### Applications
#### 5.1.1 Auto-Zoom Imaging
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Year**} & \multirow{2}{*}{**Tuning Principle**} & \multirow{2}{*}{**Construction**} & **Dielectric** & \multirow{2}{*}{**Focusing**} & \multirow{2}{*}{**Absility**} & \multirow{2}{*}{**Response Time**} & \multirow{2}{*}{**DE Material**} & \multirow{2}{*}{**Ref.**} \\  & & & **Field** & & & & & \\  & & & **Strength** & & & & & \\ \hline
2011 & Deformation-based & Monolithic & 150 V/\(\mu\)m & - & - & Nitrile rubber & [46] \\
2011 & Deformation-based & Monolithic & 58 V/\(\mu\)m & 16.72–273 mm & 60 ms & Acrylic (VHB 4905) & [30] \\
2012 & Deformation-based & Monolithic & 25 V/\(\mu\)m & 12.5–15.5 cm & - & Silicone (R-2652) & [32] \\
2013 & Deformation-based & Monolithic & 40 V/\(\mu\)m & - & - & Silicone & [78] \\
2013 & Deformation-based & Monolithic & 45 V/\(\mu\)m & 16 cm–770 cm & \(<\)1 s & Acrylic (VHB 4905) & [64] \\  & & & & \(<\)450 ms (drive) & & & \\
2014 & Deformation-based & Monolithic & 13.3 V/\(\mu\)m & 25.4–105.2 mm & \(<\)700 ms & & \\  & & & & (recover) & & & \\
2014 & Deformation-based & Monolithic & 36 V/\(\mu\)m & 13.1–16.1 mm & - & & \\  & & & & Aperture & & & \\  & & & & 1.85 mm: & & & \\
2015 & Deformation-based & Monolithic & - & 3–5.6 mm & 540 ms (drive) & Material Compound, & \\  & & & & Aperture & 240 ms (recover) & Trigonov & \\  & & & & 0.376 mm: & & & 101-455-ps) & \\  & & & & 400–620\(\mu\)m & & & & \\
2016 & Displacement-based & Composite & 17.5 V/\(\mu\)m & 1.8–7.8 mm & \(<\)1 ms & Silicone (Elastosil & [70] \\
2017 & Deformation-based & Array & 5 V/\(\mu\)m & 950 mm-\(\infty\) & - & Acrylic (VHB 4910) & [73] \\
2017 & Displacement-based & Monolithic & 200 V/\(\mu\)m & 15.4–20 cm & 23 ms (drive) & Silicone (Elastosil & [42] \\
2018 & Displacement-based & Metalenses & - & 50–103.5 mm & - & Acrylic (VHB 4905) & [77] \\
2019 & Deformation-based & Monolithic & 44.1 V/\(\mu\)m & Zoom ratio: & - & Acrylic (VHB 4910) & [65] \\  & & & & 180\% & & Silicone & \\  & & & & & & \\
2020 & Deformation-based & Monolithic & 25 V/\(\mu\)m & 4.32–8.35 mm & 7.1 ms & (PDMS-MVS, & [80] \\  & & & & & PDMS-MOS) & \\
2021 & Deformation-based & Monolithic & 41 V/\(\mu\)m & 26.1–33.6 mm & - & Silicone (LSR 4305, 3 & wt\% CuPc) & [81] \\
2022 & Displacement-based & Composite & 24 V/\(\mu\)m & 20–850 mm & 330 ms (drive) & Unimorph & \\  & & & & 100 ms (recover) & & nanocomposite & \\  & & & & & 124 ms (drive) & & \\
2023 & Displacement-based & Composite & 71.4 V/\(\mu\)m & 5.2–19.5 mm & 203 ms (recover) & Acrylic (VHB 4905) & [82] \\
2024 & Displacement-based & Composite & 33.6 V/\(\mu\)m & 6.3–12.0 mm & 150 ms (drive) & Acrylic (VHB 4905) & [83] \\
2025 & Displacement-based & Composite & 33.6 V/\(\mu\)m & \(-\)118—1476 mm, & 185 ms (drive) & Acrylic (VHB 4905) & [84] \\  & & & & 118–1476 mm & 296 ms (recover) & Acrylic (VHB 4905) & [82] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of DETL performance (“\({}^{\prime}\) indicates unknown). lightweight and rapid response advantages, DETL is well-suited to pursuing thin and light smartphone designs. With the continuous improvement of material properties and manufacturing processes, DETL-based auto-zoom imaging systems are expected to achieve a wider zoom range, faster response speed, and better image quality, significantly enhancing the overall performance of smartphone lenses. With its low power consumption and flexible deformation characteristics, this auto-zoom technology is also suitable for portable cameras, endoscopes, smart glasses, and machine vision, among other fields, demonstrating broad application prospects. DETL must accelerate technological breakthroughs in lowering driving voltage, increasing cycle life, and closed-loop control of focal length field to fully capitalise on its advantages.