High-Density μLED-Based Optical Cochlear Implant With Improved Thermomechanical Behavior.
High-Density μLED-Based Optical Cochlear Implant With Improved Thermomechanical Behavior.
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DOI：
10.3389/fnins.2018.00659
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发表时间：
2018
影响因子：
4.3
通讯作者：
Ruther P
中科院分区：
文献类型：
--
作者：
Klein E;Gossler C;Paul O;Ruther P
本研究报道了一种具有优化热机械性能的光学人工耳蜗（oCI）的实现，用于光遗传学实验。oCI探头由144个微型发光二极管（μ led）组成，分布在一个可弯曲的1.5 cm长、350 μm宽、26 μm厚的探头轴上，通过n × p矩阵互连单独控制。与我们之前基于不同热膨胀系数的聚酰亚胺（PI）和环氧树脂的方法相反，μ led和互连线现在被嵌入到单一的、生物相容性的、高度透明的环氧材料的三层堆叠中。与早期方法的材料对相比，新材料组合的结果是明显减少了热机械弯曲。我们开发了一种旋转涂层工艺，使整个载体晶圆上的环氧树脂层厚度变化小于7%，厚度变化小于5 μm。我们观察到环氧树脂层的交联很大程度上取决于旋涂参数，旋涂参数与不同密度环氧树脂组分的潜在分离有关。此外，还研究了不同的金属化层和相应的附着力促进层。我们确定了碳化硅与钛基金属化的组合，以提供最高的剥离强度，实现与环氧树脂的附着力提高两倍。为了获得较高的工艺产率，我们利用电化学溶解牺牲铝层建立了无应力植入释放。直接比较使用单一环氧树脂材料和PI和环氧树脂组合的oCI探针，发现仅使用环氧树脂的探针具有最小的热机械弯曲和可忽略的滞后。热探针表征表明，在μLED直流电流高达10 mA的情况下，温度升高限制在1 K以内，这取决于刺激时间和探针周围的介质。在10 mA、10 kHz、占空比为10%的条件下，该器件的光输出功率和峰值波长分别为0.82 mW和462 nm。光功率对应于407 mW/mm2的辐射发射，足以使用通道视紫红质-2进行光遗传学实验。
This study reports the realization of an optical cochlear implant (oCI) with optimized thermomechanical properties for optogenetic experiments. The oCI probe comprises 144 miniaturized light-emitting diodes (μLEDs) distributed along a bendable, 1.5-cm-long, 350-μm-wide and 26-μm-thick probe shaft, individually controlled via a n × p matrix interconnection. In contrast to our earlier approach based on polyimide (PI) and epoxy resin with different thermal expansion coefficients, the μLEDs and interconnecting wires are now embedded into a triple-layer stack of a single, biocompatible, and highly transparent epoxy material. The new material combination results in a pronounced reduction of thermomechanical bending in comparison with the material pair of the earlier approach. We developed a spin-coating process enabling epoxy resin layers down to 5 μm at thickness variations of less than 7% across the entire carrier wafer. We observed that the cross-linking of epoxy resin layers strongly depends on the spin-coating parameters which were found to be correlated to a potential separation of epoxy resin components of different densities. Furthermore, various metallization layers and corresponding adhesion promoting layers were investigated. We identified the combination of silicon carbide with a titanium-based metallization to provide the highest peeling strength, achieving an adhesion to epoxy improved by a factor of two. In order to obtain a high process yield, we established a stress-free implant release using the electrochemical dissolution of a sacrificial aluminum layer. The direct comparison of oCI probe variants using a single epoxy material and the combination of PI and epoxy resin revealed that the epoxy-resin-only probe shows minimal thermomechanical probe bending with a negligible hysteresis. The thermal probe characterization demonstrated that the temperature increase is limited to 1 K at μLED DC currents of up to 10 mA depending on the stimulation duration and the medium surrounding the probe. The optical output power and peak wavelengths of the new oCI variant were extracted to be 0.82 mW and 462 nm when operating the μLEDs at 10 mA, 10 kHz, and a duty cycle of 10%. The optical power corresponds to a radiant emittance of 407 mW/mm2, sufficient for optogenetic experiments using channelrhodopsin-2.
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影响因子：
39.3
作者：
Nyns ECA;Kip A;Bart CI;Plomp JJ;Zeppenfeld K;Schalij MJ;de Vries AAF;Pijnappels DA
通讯作者：
Pijnappels DA
影响因子：
1.2
作者：
Felix, Sarah H.;Shah, Kedar G.;Pannu, Satinderpall S.
通讯作者：
Pannu, Satinderpall S.
影响因子：
5.1
作者：
Lin Mengzhe;Cao Qing;Chen Lianghui
通讯作者：
Chen Lianghui
DOI：
10.1109/tbcas.2013.2282318
发表时间：
2013-10-01
影响因子：
5.1
作者：
Kwon, Ki Yong;Sirowatka, Brenton;Li, Wen
通讯作者：
Li, Wen
影响因子：
25
作者：
Boyden, ES;Zhang, F;Deisseroth, K
通讯作者：
Deisseroth, K