Abstract: There is provided a substrate for crystal growth used for a vapor phase growth of a crystal, wherein a plurality of seed crystal substrates made of a group III nitride crystal are arranged in a disc shape, so that their main surfaces are parallel to each other and adjacent lateral surfaces are in contact with each other; and the plurality of seed crystal substrates constituting at least a portion other than a peripheral portion of the substrate for crystal growth respectively has a main surface whose planar shape is a regular hexagon, and a honeycomb pattern obtained by matching the seed crystal substrates has two or more symmetries, when the substrate for crystal growth is rotated once, with an axis passing through a center of a main surface of the substrate for crystal growth and orthogonal to the main surface as a central axis.

Abstract: There is provided a substrate for crystal growth used for a vapor phase growth of a crystal, wherein a plurality of seed crystal substrates made of a group III nitride crystal are arranged in a disc shape, so that their main surfaces are parallel to each other and adjacent lateral surfaces are in contact with each other; and the plurality of seed crystal substrates constituting at least a portion other than a peripheral portion of the substrate for crystal growth respectively has a main surface whose planar shape is a regular hexagon, and a honeycomb pattern obtained by matching the seed crystal substrates has two or more symmetries, when the substrate for crystal growth is rotated once, with an axis passing through a center of a main surface of the substrate for crystal growth and orthogonal to the main surface as a central axis.

Abstract: An image readout apparatus for photoelectrically reading an image of an original document which is suitable for use in a facsimile apparatus to transmit and receive the image data of the original document. This apparatus includes: a CCD image sensor to read an image and generate electric data indicative of the image; a reference white plate; a memory to store the reference data obtained by reading the white plate by the image sensor; a correction circuit to correct the image data obtained by reading an original document with the image sensor on the basis of the reference data stored in the memory; and a control circuit for allowing the white plate to be read by the image sensor and allowing the reference data to be stored in the memory even when the original document cannot be read by the image sensor.