Abstract: A first substrate includes a first surface and a second surface opposite to the first surface. A second substrate includes a third surface and a fourth surface opposite to the third surface. A third substrate includes a fifth surface and a sixth surface opposite to the fifth surface. The first substrate is made of an insulator, and includes a mounting portion for mounting an electronic element at the first surface, and the mounting portion is a rectangular shape. The third substrate is made of a carbon material, and the fifth surface is connected to at least the second surface at location overlapped with the mounting portion in plan view. The third substrate has a larger heat conduction in a direction perpendicular to the longitudinal direction of the mounting portion than heat conduction in the longitudinal direction of the mounting portion in plan view.

Abstract: A wiring board includes an insulating substrate including a first surface and a mounting portion for an electronic component on the first surface, the insulating substrate having a rectangular shape in a plan view of the first surface; a via conductor located inside the insulating substrate and at a corner portion of the insulating substrate in a plane perspective, and extending in a thickness direction of the insulating substrate; a wiring conductor located on the first surface and connecting the mounting portion and the via conductor to each other; and a heat dissipation portion located inside the insulating substrate at a position overlapping the mounting portion in a plane perspective view, wherein the first surface includes, between the heat dissipation portion and the via conductor in a plane perspective view, a first region surrounded by the wiring conductor in a plan view.

Abstract: A substrate for mounting electronic element includes: a first substrate including a first surface and a second surface opposite to the first surface; a second substrate including a third surface and a fourth surface opposite to the third surface; and heat dissipation bodies each including a fifth surface and a sixth surface opposite to the fifth surface. The first substrate includes at least one mounting portion for at least one electronic element at the first surface. Heat conduction of the heat dissipation bodies in a direction perpendicular to a longitudinal direction of the at least one mounting portion and perpendicular to a direction along opposite sides of the second substrate is greater than heat conduction of the heat dissipation bodies in the longitudinal direction of the at least one mounting portion and in the direction along opposite sides of the second substrate in a transparent plan view of the substrate.

Abstract: A first substrate includes a first surface and a second surface opposite to the first surface. A second substrate includes a third surface and a fourth surface opposite to the third surface. A third substrate includes a fifth surface and a sixth surface opposite to the fifth surface. The first substrate is made of an insulator, and includes a mounting portion for mounting an electronic element at the first surface, and the mounting portion for mounting the electronic element is a rectangular shape. The third substrate is made of a carbon material, and the fifth surface is connected to at least the second surface at location overlapped with the mounting portion for mounting the electronic element in plan view. The third substrate has a larger heat conduction in a direction perpendicular to the longitudinal direction of the mounting portion than heat conduction in the longitudinal direction of the mounting portion in plan view.

Abstract: A substrate for mounting electronic element includes: a first substrate including a first surface and a second surface opposite to the first surface; a second substrate including a third surface and a fourth surface opposite to the third surface; and heat dissipation bodies each including a fifth surface and a sixth surface opposite to the fifth surface. The first substrate includes at least one mounting portion for at least one electronic element at the first surface. Heat conduction of the heat dissipation bodies in a direction perpendicular to a longitudinal direction of the at least one mounting portion and perpendicular to a direction along opposite sides of the second substrate is greater than heat conduction of the heat dissipation bodies in the longitudinal direction of the at least one mounting portion and in the direction along opposite sides of the second substrate in a transparent plan view of the substrate.

Abstract: An electronic element mounting substrate includes: a first substrate including a first principal face; a second substrate located inside the first substrate in a plan view of the electronic element mounting substrate, the second substrate being made of a carbon material; a third substrate located between the first substrate and the second substrate in the plan view, the third substrate being made of a carbon material; and a first mounting portion for mounting a first electronic element, the first mounting portion being located on the first principal face side in a thickness direction of the substrate. The second substrate and the third substrate each have a low heat conduction direction and a high heat conduction direction. The second substrate and the third substrate is arranged so that the low heat conduction directions thereof are perpendicular to each other, and the high heat conduction directions thereof are perpendicular to each other.

Abstract: A wiring board includes an insulating substrate including a first surface and a mounting portion for an electronic component on the first surface, the insulating substrate having a rectangular shape in a plan view of the first surface; a via conductor located inside the insulating substrate and at a corner portion of the insulating substrate in a plane perspective, and extending in a thickness direction of the insulating substrate; a wiring conductor located on the first surface and connecting the mounting portion and the via conductor to each other; and a heat dissipation portion located inside the insulating substrate at a position overlapping the mounting portion in a plane perspective view, wherein the first surface includes, between the heat dissipation portion and the via conductor in a plane perspective view, a first region surrounded by the wiring conductor in a plan view.

Abstract: An electronic component mounting substrate includes: an insulating substrate having a recess that opens in a main surface of the insulating substrate, the recess for mounting an electronic component; a metal layer located on a bottom surface of the recess; an external electrode located on the other main surface of the insulating substrate, the other main surface opposite to the main surface; a connection wiring located between the metal layer and the external electrode in a thickness direction of the insulating substrate; a plurality of first vias that connects the metal layer and the connection wiring and that is located along a side wall of the recess in a perspective plan view; and a plurality of second vias that connects the connection wiring and the external electrode and that is located in a strip shape in the perspective plan view.

Abstract: An electronic element mounting substrate includes: a first substrate including a first principal face and a second principal face opposite to the first principal face; a second substrate including a third principal face and a fourth principal face opposite to the third principal face, the second substrate being made of a carbon material; and a plurality of via conductors that are arranged in the first substrate. The second substrate is located inside the first substrate in the plan view. In the plan view, the plurality of via conductors are arranged with the second substrate in between. In the plan view, heat conduction of the second substrate is greater in a direction perpendicular to a direction in which the plurality of via conductors are arranged with the second substrate in between than in the direction in which the plurality of via conductors are arranged with the second substrate in between.

Abstract: An electronic element mounting substrate includes: a first substrate including a first principal face; a second substrate located inside the first substrate in a plan view of the electronic element mounting substrate, the second substrate being made of a carbon material; a third substrate located between the first substrate and the second substrate in the plan view, the third substrate being made of a carbon material; and a first mounting portion for mounting a first electronic element, the first mounting portion being located on the first principal face side in a thickness direction of the substrate. The second substrate and the third substrate each have a low heat conduction direction and a high heat conduction direction. The second substrate and the third substrate is arranged so that the low heat conduction directions thereof are perpendicular to each other, and the high heat conduction directions thereof are perpendicular to each other.

Abstract: A wiring board includes an insulating substrate including a cutout portion that opens in a main surface of the insulating substrate and a side surface of the insulating substrate, an inner surface electrode on an inner surface of the cutout portion, an external electrode on the main surface of the insulating substrate, and a connecting section where the inner surface electrode and the external electrode are connected to each other. The connecting section is thicker than the inner surface electrode and the external electrode.

Abstract: A first substrate includes a first surface and a second surface opposite to the first surface. A second substrate includes a third surface and a fourth surface opposite to the third surface. A third substrate includes a fifth surface and a sixth surface opposite to the fifth surface. The first substrate is made of an insulator, and includes a mounting portion for mounting an electronic element at the first surface, and the mounting portion for mounting the electronic element is a rectangular shape. The third substrate is made of a carbon material, and the fifth surface is connected to at least the second surface at location overlapped with the mounting portion for mounting the electronic element in plan view. The third substrate has a larger heat conduction in a direction perpendicular to the longitudinal direction of the mounting portion than heat conduction in the longitudinal direction of the mounting portion in plan view.

Abstract: A substrate for mounting electronic element includes: a first substrate including a first surface and a second surface opposite to the first surface; a second substrate including a third surface and a fourth surface opposite to the third surface; and heat dissipation bodies each including a fifth surface and a sixth surface opposite to the fifth surface. The first substrate includes at least one mounting portion for at least one electronic element at the first surface. Heat conduction of the heat dissipation bodies in a direction perpendicular to a longitudinal direction of the at least one mounting portion and perpendicular to a direction along opposite sides of the second substrate is greater than heat conduction of the heat dissipation bodies in the longitudinal direction of the at least one mounting portion and in the direction along opposite sides of the second substrate in a transparent plan view of the substrate.

Abstract: A wiring board includes an insulating substrate that is rectangular in a plan view, a plurality of mount electrodes arranged to face each other on a first main surface of the insulating substrate along a pair of opposing sides of the insulating substrate in a plan view, a plurality of terminal electrodes arranged to face each other on a second main surface of the insulating substrate along the pair of opposing sides of the insulating substrate in a perspective plan view, and an inner metal layer arranged inside the insulating substrate and extending in a direction perpendicular to the pair of opposing sides of the insulating substrate in a perspective plan view.

Abstract: An electronic component mounting substrate includes: an insulating substrate having a recess that opens in a main surface of the insulating substrate, the recess for mounting an electronic component; a metal layer located on a bottom surface of the recess; an external electrode located on the other main surface of the insulating substrate, the other main surface opposite to the main surface; a connection wiring located between the metal layer and the external electrode in a thickness direction of the insulating substrate; a plurality of first vias that connects the metal layer and the connection wiring and that is located along a side wall of the recess in a perspective plan view; and a plurality of second vias that connects the connection wiring and the external electrode and that is located in a strip shape in the perspective plan view.

Abstract: A wiring board includes an insulating substrate including a cutout portion that opens in a main surface of the insulating substrate and a side surface of the insulating substrate, an inner surface electrode on an inner surface of the cutout portion, an external electrode on the main surface of the insulating substrate, and a connecting section where the inner surface electrode and the external electrode are connected to each other. The connecting section is thicker than the inner surface electrode and the external electrode.

Abstract: A wiring board includes an insulating substrate that is rectangular in a plan view, a plurality of mount electrodes arranged to face each other on a first main surface of the insulating substrate along a pair of opposing sides of the insulating substrate in a plan view, a plurality of terminal electrodes arranged to face each other on a second main surface of the insulating substrate along the pair of opposing sides of the insulating substrate in a perspective plan view, and an inner metal layer arranged inside the insulating substrate and extending in a direction perpendicular to the pair of opposing sides of the insulating substrate in a perspective plan view.

Abstract: A wiring board includes an insulating substrate that is rectangular in a plan view, a plurality of mount electrodes arranged to face each other on a first main surface of the insulating substrate along a pair of opposing sides of the insulating substrate in a plan view, a plurality of terminal electrodes arranged to face each other on a second main surface of the insulating substrate along the pair of opposing sides of the insulating substrate in a perspective plan view, and an inner metal layer arranged inside the insulating substrate and extending in a direction perpendicular to the pair of opposing sides of the insulating substrate in a perspective plan view.

Abstract: A wiring board includes an insulating substrate, mount electrodes arranged to face each other on a first main surface of the insulating substrate along a pair of opposing sides of the insulating substrate in a plan view, and terminal electrodes arranged to face each other on a second main surface of the insulating substrate along another pair of opposing sides of the insulating substrate in a perspective plan view.

Abstract: An electronic component mounting substrate includes an insulating base having a rectangular shape in plan view and including a first main surface, a second main surface facing the first main surface, and a recess open on the first main surface, a band-shaped metal layer on a sidewall of the recess, and an electrode extending from a bottom surface of the recess into the insulating base. The electrode has an end disposed in the insulating base, and the end includes an inclined portion inclined toward the second main surface.