Patent ID: 7252653
Filing Date: 2007-08-07
Classification: A61M

Abstract:
1. A liquid injection needle used for percutaneous self-administration or a dental treatment comprising: a hollow needle part for injecting a liquid; a supporting part to which the needle part is fixed, wherein said hollow needle part comprises wherein said distal end has a distal side outer diameter that is constant over an entire length of the distal end, and said middle part has an outer diameter that gradually reduces toward said distal end to smoothly connect said distal end and said proximal end, wherein said distal side outer diameter is equal to or greater than 0.1 mm and equal to or less than 0.25 mm, and a proximal side outer diameter is greater than said distal side outer diameter and equal to or greater than 0.3 mm and equal to or less than 2 mm, a distal side internal diameter is larger than 0.05 mm and smaller than 0.15 mm, and a proximal side internal diameter is equal to or larger than 0.20 mm and equal to or smaller than 1.2 mm, wherein said puncturing part has a total length greater than the entire length of the distal end, the total length being equal to or greater than 1.5 mm and equal to or less than 15 mm, wherein the entire length of the distal end is ⅔ or more of the total length of the puncturing part when the total length of the puncturing part is equal to or greater than 1.5 mm and equal to or less than 5 mm, wherein the entire length of the distal end is ⅗ or more of the total length of the puncturing part when the total length of the puncturing part is greater than 5 mm and equal to or less than 15 mm, and wherein said needle part possesses a flow path resistance equal to or less than 350 gram-force under a sustained water flow rate of 20 μl/sec.