Microchip
A flow path groove is formed in the surface of at least one of two resin substrates; the two resin substrates are joined with the surface in which the flow path groove is formed facing inward; a through-hole having a substantially round cross section is formed in either one of the two resin substrates such that the through-hole connects with the flow path groove from the surface opposite the surface where the two resin substrates join; protruding parts, which protrude in the direction of thickness of the resin substrates and are disposed enclosing the through-hole, are formed in the surface on the opposite side; a space, which has a substantially round cross-sectional shape concentric with the through-hole and has depth in the same direction as the direction of thickness of the resin substrates, is formed in the joined surfaces when the protruding parts are projected from the direction substantially perpendicular to the joined surfaces; and the correlation of fc>fa is satisfied when the edges on the base end side of the through-hole are projected onto the joined surfaces from a substantially perpendicular direction, where the diameter on the base end side of the through-hole is fa and the diameter on the end edge side of the space touching the joined surfaces is fc.
1. A microchip comprising:
a plurality of resin substrates;
a flow channel groove formed in a surface of at least one resin substrate of the plurality of resin substrates, the plurality of resin substrates being joined with a face facing inward where the flow channel groove is formed, and at least one resin substrate of the plurality of resin substrates having formed therein a through-hole of an almost circularly cross-sectional shape leading to the flow channel groove from a face of an opposite side to the face where the plurality of resin substrates are joined; and
a protrusion, in the face of the opposite side, protruding in a thickness direction of the at least one resin substrate and integrally formed with the at least one resin substrate so as to surround the through-hole;
wherein the microchip in which a space having an almost circularly cross-sectional shape concentric with the through-hole and a depth in the same direction as the thickness direction of the at least one resin substrate is formed on a joint face of the at least one resin substrate or another resin substrate of the plurality of resin substrates which is the joint face where the protrusion is projected from an almost perpendicular direction to the joint face;
wherein, when a base end side edge of the through-hole is projected on the joint face from the almost perpendicular direction, a relationship of φc>φa is satisfied and a relationship of φc≧φb is satisfied, provided that a diameter of the base end side of the through-hole is designated as φa, a diameter of the based end of the protrusion where the base end of the protrusion is projected on the joint face from the almost perpendicular direction is designated as φb and a diameter of an end edge side of the space making contact with the joint face is designated as φc;
wherein the space is formed in the joint face of the plurality of resin substrates in which the flow channel groove has been formed in the at least one resin substrate of the plurality of resin substrates;
wherein the space has a peripheral wall face slanting from the end edge side of the space toward the base end side edge of the through-hole or a tip side edge of the through-hole; and
wherein the microchip further satisfies the relationship of T≦Tc≦Td, provided that the depth of the space is designated as Tc, the thickness of the at least one resin substrate is designated as T, and the depth of the through-hole is designated as Td, respectively.
2. The microchip of claim 1 , wherein the microchip further satisfies a relationship of 2.5×φb>φc.
3. The microchip of claim 1 , wherein the depth of the space is such that a clearance remains between the base end side edge of the through-hole and the joint face even when the plurality of resin substrates is joined.
4. The microchip of claim 3 , wherein the microchip further satisfies the relationship of Ta≦Tc, provided that the depth of the flow channel groove is designated as Ta.
5. The microchip of claim 3 , wherein the tip side edge of the through hole is the base side edge of the through-hole and is at the tip of the protrusion surrounding an aperture.