led along the top surface of the fins 1 to the surface of the column 2 in addition to the air flow 5 a thereby further improving the heat dissipation properties 0067 fig4 a shows a heatsink which has the fins 1 disposed radially with one point on the base line 9 a as base point in this case the air flow area can be increased as in the case of fig3 b compared with fig3 a further enhancing the heat dissipation properties 0068 fig4 b shows the heatsink of fig3 a in which the fins 1 are bent at right angles such heatsinks can also achieve the same performance properties as the heatsinks illustrated in fig3 b and fig4 a 0070 fig5 shows a perspective view of the fins of the heatsink in accordance with the first and second preferred embodiments of the present invention as the external shape of the fins 1 in fig5 illustrates by forming protrusions and recesses on the surface of the fins 1 of the heatsink the surface area increases enhancing the heat dissipating capability the protrusions and recesses can be formed only on a part of the fins 1 furthermore even if they are formed on some of the fins the same effect can be obtained the surface of the fins 1 can be provided with dimples the fins 1 can be formed such that the width near the bottom and the top end are the same as shown in fig5 a the fins 1 can also be formed such that they have diminishing taper either from bottom to top.