Patent ID: 8235073

Claim:
A valve unit comprising: a channel formed in a platform, wherein the channel comprises a protrusion portion having a first channel depth, and channel groove portions disposed on opposite sides of the protrusion portion and having a second channel depth which is greater than the first channel depth so that the protrusion portion forms a step with respect to the channel groove portions; a valve filler which comprises a phase transition material that is disposed and hardened in the protrusion portion of the channel in a solid state at room temperature to close the channel and is melted when energy is applied thereto; and at least one capillary channel which extends from a sidewall of the protrusion portion of the channel and into which the valve filler flows when the valve filler is melted, wherein the at least one capillary channel has a cross-sectional area which is less than a cross-sectional area of the channel.