The white light‐emitting diode (LED) modules, in which the GaN‐based blue‐LED chip with 4 × 4 arrayed pixels are packaged with chip‐on‐board technique and welded on a print circuit board, are fabricated for both illumination and visible light communication (VLC). The effects of the mesa size on the characteristic features are explored. It shows that the pixels with small size can sustain high saturated current density. Under the saturated current density, the highest luminous flux of 278.4 lm can be obtained by using the largest pixel of 160 µm‐diameter, or the highest 3‐dB modulation bandwidth of 127.3 MHz can be obtained by using the smallest pixels of 60 µm‐diameter. In case the white‐LED module works for a long time, the injected current density should be far away from the saturated current density. On condition that the 3‐dB modulation bandwidth of 100 MHz is required, the white‐LED module with 100 µm‐diameter pixels is proposed and the luminous flux can reach 164.8 lm. Subsequently, the electrode size is optimized to get higher luminous flux. By enlarging the p‐electrode, the white‐LED module with 120 µm‐diameter pixels can achieve the luminous flux of 235.2 lm while the 3‐dB modulation bandwidth holds 100 MHz.
This paper employs control techniques to analyze kinematic relationships via block diagrams for planetary gear systems. The revealed tangent-velocity equations at each contact point of the mechanical gearsets are utilized to plot the block diagrams. Then, the concepts of feedback and feedforward strategies are adopted to illustrate speed-reduction and increasing functions in kinematics with sensitivity analysis. The structural difference between unusual planetary gears and common ones is also explained based on the characteristic equation of feedback strategies for structural constraints in terms of stability conditions. A cam-controlled planetary gear is further illustrated for the constraint and kinematic analysis by using the block diagram technique and characteristic equation, and the computational simulations for the sensitivity and the motion output of this planetary gear are obtained. Through the correspondence between control and kinematics, this paper provides a guide for engineers in various fields to easily understand the function of mechanical design.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.