Thermally-conductive sheet, LED mounting substrate, and LED module

摘要

The present invention provides a thermally-conductive sheet excellent in heat dissipation properties. The thermally-conductive sheet includes a polymer matrix and a thermally-conductive filler dispersed in the polymer matrix. The present invention is a thermally-conductive sheet including a polymer matrix and non-spherical particles of a thermally-conductive filler that are dispersed in the polymer matrix. At least a part of the thermally-conductive filler particles are oriented in a thickness direction of the sheet. When a portion of the sheet where the thermally-conductive filler particles have the highest degree of orientation in the thickness direction of the sheet is defined as a center of orientation, and an axis passing through the center of orientation and perpendicular to sheet surfaces is defined as a central axis of orientation, the thermally-conductive sheet has a region where the thermally-conductive filler particles are oriented toward one point on the central axis of orientation and where the degree of orientation of the thermally-conductive filler particles in the thickness direction of the sheet decreases from the center of orientation toward a periphery of the sheet.

主权项

1. A thermally-conductive sheet comprising a polymer matrix and non-spherical particles of a thermally-conductive filler that are dispersed in the polymer matrix, wherein
at least a part of the thermally-conductive filler particles are oriented in a thickness direction of the sheet, wherein a portion of the sheet where the thermally-conductive filler particles have the highest degree of orientation in the thickness direction of the sheet is defined as a center of orientation, and an axis passing through the center of orientation and perpendicular to sheet surfaces is defined as a central axis of orientation, the thermally-conductive sheet has a region where the thermally-conductive filler particles are oriented toward one point on the central axis of orientation and where the degree of orientation of the thermally-conductive filler particles in the thickness direction of the sheet decreases from the center of orientation toward a periphery of the sheet, 60% or more of the thermally conductive filler particles are oriented at an angle of 45° or more relative to the sheet surfaces, and a ratio λ1/λ2 is 1.5 or more, where λ1 represents a thermal conductivity measured by applying heat to one of the sheet surfaces that is closer to the one point on the central axis of orientation and λ2 represents a thermal conductivity measured by applying heat to the other of the sheet surfaces that is farther from the one point on the central axis of orientation.