Microfluidic device with droplet pre-charge on input

An electrowetting on dielectric (EWOD) device comprising:

• a first substrate and an opposing second substrate defining a gap between the first and second substrates, each substrate including an insulating surface facing the pap;
• an array of elements comprising a plurality of individual elements that are actuatable for manipulation of a liquid droplet within the gap, each individual element including a plurality of electrode elements to which actuation voltages are applied;
• and
• a pre-charging structure that includes a channel in fluid communication with the gap and that is configured to receive a fluid reservoir for generation of the liquid droplet, and the pre-charging structure includes an electrical element electrically exposed to the channel;
• wherein the electrical element pre-charges the fluid reservoir within the channel, and a portion of the gap containing the liquid droplet spaced apart from the channel is electrically isolated from the electrical element such that the liquid droplet is at a floating electrical potential when located within said portion of the gap;
• wherein the pre-charging structure comprises an input structure defining an input channel in fluid communication with the gap, wherein the input channel is the channel that is configured to receive the input of the fluid reservoir;
• and
• wherein the electrical element comprises an externally connected pre-charging element that is inserted into the input channel and is located within the input channel spaced apart from the plurality of electrodes.

An electrowetting on dielectric (EWOD) device comprising:

• a first substrate and an opposing second substrate defining a gap between the first and second substrates, each substrate including an insulating surface facing the gap;
• an array of elements comprising a plurality of individual elements that are actuatable for manipulation of a liquid droplet within the gap, each individual element including a plurality of electrode elements to which actuation voltages are applied;
• and
• a pre-charging structure that includes an input channel in fluid communication with the gap and that is configured to receive a fluid reservoir for generation of the liquid droplet within the gap, and the pre-charging structure includes an electrical element electrically exposed to the channel;
• wherein the electrical element pre-charges the fluid reservoir within the channel, and a portion of the gap containing the liquid droplet spaced apart from the channel is electrically isolated from the electrical element such that the liquid droplet is at a floating electrical potential when located within said portion of the gap;
• wherein the channel comprises a side opening between the first and second substrates that is in fluid communication with the gap;
• wherein the EWOD device further includes a side support that defines a portion of the input channel leading to the side opening;
• and
• wherein the side support is electrically conductive.