Patent ID: 8293183

Claim:
A honeycomb filter for trapping and removing solid components contained in a fluid, the honeycomb filter comprising: a plurality of porous partition portions each forming a cell, the cell being open at one end and closed at the other end and serving as a flow path of the fluid; and a trapping layer for trapping and removing the solid components contained in the fluid, the trapping layer being disposed on each of the partition portions, wherein the partition portions have a thickness t p of 150 μm or more and 460 μm or less, and the trapping layer has an average thickness t Ave of 5 μm or more and 80 μm or less, and a film thickness ratio Y 1 of a downstream thickness t l to an up- and mid-stream thickness t hm satisfies the relationship of the formula (1), wherein t h denotes the thickness of the trapping layer in an upstream region of the honeycomb filter, t m denotes the thickness of the trapping layer in a midstream region of the honeycomb filter, t l denotes the thickness of the trapping layer in a downstream region of the honeycomb filter, and t hm denotes the mean value of the upstream thickness t h and the midstream thickness t m , a film thickness ratio Y 2 of a maximum thickness t max to an average thickness t Ave satisfies the relationship of the formula (2), wherein t max denotes the maximum thickness of the trapping layer, and t Ave denotes the average thickness of the trapping layer, and the hydraulic diameter HD in of the cell on the inlet side satisfies the relationship of the formula (3). −4/375 ·t Ave +2.05 ≦Y 1 ≦17/375 ·t Ave +10.23 (1) Y 2 ≦−1/15 ·t Ave +8.33 (2) 0.95≦HD in ≦2.0 (3)