Honeycomb filter

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 tp of 150 μm or more and 460 μm or less, and
• the trapping layer has an average thickness tAve of 5 μm or more and 80 μm or less, and
• a film thickness ratio Y1 of a downstream thickness t1 to an up- and mid-stream thickness thm satisfies the relationship of the formula (1), wherein th denotes the thickness of the trapping layer in an upstream region of the honeycomb filter, tm denotes the thickness of the trapping layer in a midstream region of the honeycomb filter, t1 denotes the thickness of the trapping layer in a downstream region of the honeycomb filter, and thm denotes the mean value of the upstream thickness th and the midstream thickness tm,
• a film thickness ratio Y2 of a maximum thickness tmax to an average thickness tAve satisfies the relationship of the formula (2), wherein tmax denotes the maximum thickness of the trapping layer, and tAve denotes the average thickness of the trapping layer, and
• the hydraulic diameter HDin of the cell on the inlet side satisfies the relationship of the formula (3).
• −4/375·tAve+2.05≦Y1≦−17/375·tAve+10.23 (1)
• Y2≦−1/15·tAve+8.33 (2)
• 0.95≦HDin≦2.0 (3)