Abstract: According to one embodiment, an electronic apparatus includes a processor. The processor is configured to acquire position information indicating first and second installation positions of a plurality of pieces of equipment receive characteristic information of a first piece of equipment obtained from a first propagation characteristic and a second propagation characteristic, and characteristic information of a second piece of equipment obtained from a third propagation characteristic and a fourth propagation characteristic. The processor is configured to estimate a position where each of the first and second pieces of equipment is installed, based on the position information, and the characteristic information of the first and the second piece of equipment.

Abstract: An imaging lens includes a first lens; a second lens; a third lens having negative refractive power; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The sixth lens is formed in a shape so that a surface thereof on the image plane side is concave at a paraxial region thereof. The seventh lens is formed in a shape so that a surface thereof on the image plane side is aspheric. The first lens and the second lens have a specific composite focal length. The third lens have a specific focal length.

Abstract: An imaging lens includes a first lens; a second lens; a third lens having negative refractive power; a fourth lens having positive refractive power; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens has at least one aspheric surface. The fifth lens has two aspheric surfaces. The sixth lens is formed in a shape so that a surface thereof on the object side is convex at a paraxial region thereof and a surface thereof on the image plane side is concave at a paraxial region thereof. The seventh lens has two aspheric surfaces.

Abstract: An imaging lens includes a first lens; a second lens; a third lens having negative refractive power; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens is formed in a meniscus shape at a paraxial region thereof. The sixth lens is formed in a shape so that a surface thereof on the object side is convex at a paraxial region thereof. The fourth lens and the fifth lens have a specific composite focal length. The sixth lens and the seventh lens have a specific composite focal length.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The sixth lens is formed in a shape so that a surface thereof on the image plane side is concave at a paraxial region thereof. The seventh lens is formed in a shape so that a surface thereof on the image plane side is aspheric. The first lens and the second lens have a specific composite focal length. The third lens have a specific focal length. The fourth lens and the fifth lens have a specific composite focal length. The sixth lens and the seventh lens have a specific composite focal length.

Abstract: An imaging lens includes a first lens group having positive refractive power; a second lens group; and a third lens group having negative refractive power, arranged in this order from an object side to an image plane side. The first lens group includes a first lens, a second lens, and a third lens. The second lens group includes a fourth lens and a fifth lens. The third lens group includes a sixth lens and a seventh lens having negative refractive power. The first lens is formed in a meniscus shape at a paraxial region thereof. The fourth lens is formed in a meniscus shape at a paraxial region thereof. The seventh lens is formed in a meniscus shape at a paraxial region thereof. The seventh lens has a specific focal length. The second lens is disposed away from the third lens by a specific distance.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens is formed in a meniscus shape at a paraxial region thereof. The third lens is formed in a shape so that a surface thereof directing to the image plane side is concave at a paraxial region thereof. The fourth lens is formed in a meniscus shape at a paraxial region thereof. The seventh lens has a specific focal length.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens having negative refractive power; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens is formed in a meniscus shape near an optical axis thereof. The third lens is formed in a meniscus shape so that a surface thereof directing to the object side is convex near an optical axis thereof. The sixth lens is formed in a meniscus shape near an optical axis thereof.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens; a third lens having negative refractive power; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens is formed in a meniscus shape near an optical axis thereof. The third lens is formed in a meniscus shape so that a surface thereof directing to the object side is convex near an optical axis thereof. The sixth lens is formed in a meniscus shape near an optical axis thereof.

Abstract: An imaging lens includes a stop; a first lens having positive refractive power; a second lens having negative refractive power; a third lens; a fourth lens having positive refractive power; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens is formed in a meniscus shape near an optical axis thereof. The third lens is formed in a shape so that a surface thereof directing to the image plane side is concave near an optical axis thereof. The sixth lens is formed in a meniscus shape near an optical axis thereof.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side with a space between each of the lenses. The second lens is formed in a shape so that a surface thereof on the object side has a positive curvature radius. The third lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius. The sixth lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius. The seventh lens has a specific Abbe's number. The fourth lens and the fifth lens have a specific composite focal length. The sixth lens and the seventh lens have a specific composite focal length.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens having positive refractive power; a sixth lens having negative refractive power; and a seventh lens, arranged in this order from an object side to an image plane side with a space between each of the lenses. The second lens is formed in a shape so that a surface thereof on the object side has a positive curvature radius. The third lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius. The seventh lens has a specific Abbe's number. The sixth lens and the seventh lens have a specific composite focal length.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side with a space between each of the lenses. The second lens is formed in a shape so that a surface thereof on the object side has a positive curvature radius. The third lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius. The sixth lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius. The seventh lens has a specific Abbe's number. The sixth lens and the seventh lens have a specific composite focal length.

Abstract: An imaging lens includes a first lens having positive refractive power; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side with a space between each of the lenses. The third lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius. The sixth lens is formed in a shape so that a surface thereof on the image plane side has a positive curvature radius. The seventh lens has a specific Abbe's number. The sixth lens has a specific focal length. The seventh lens has a specific focal length.

Abstract: An imaging lens includes a first lens; a second lens; a third lens having negative refractive power; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The sixth lens is formed in a shape so that a surface thereof on the image plane side is concave at a paraxial region thereof. The seventh lens is formed in a shape so that a surface thereof on the image plane side is aspheric. The first lens and the second lens have a specific composite focal length. The third lens have a specific focal length.

Abstract: An imaging lens includes a first lens; a second lens; a third lens having negative refractive power; a fourth lens having positive refractive power; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens has at least one aspheric surface. The fifth lens has two aspheric surfaces. The sixth lens is formed in a shape so that a surface thereof on the object side is convex at a paraxial region thereof and a surface thereof on the image plane side is concave at a paraxial region thereof. The seventh lens has two aspheric surfaces.

Abstract: An imaging lens includes a first lens; a second lens; a third lens having negative refractive power; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens is formed in a meniscus shape at a paraxial region thereof. The sixth lens is formed in a shape so that a surface thereof on the object side is convex at a paraxial region thereof. The fourth lens and the fifth lens have a specific composite focal length. The sixth lens and the seventh lens have a specific composite focal length.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The sixth lens is formed in a shape so that a surface thereof on the image plane side is concave at a paraxial region thereof. The seventh lens is formed in a shape so that a surface thereof on the image plane side is aspheric. The first lens and the second lens have a specific composite focal length. The third lens have a specific focal length. The fourth lens and the fifth lens have a specific composite focal length. The sixth lens and the seventh lens have a specific composite focal length.

Abstract: An imaging lens includes a first lens group having positive refractive power; a second lens group; and a third lens group having negative refractive power, arranged in this order from an object side to an image plane side. The first lens group includes a first lens, a second lens, and a third lens. The second lens group includes a fourth lens and a fifth lens. The third lens group includes a sixth lens and a seventh lens having negative refractive power. The first lens is formed in a meniscus shape at a paraxial region thereof. The fourth lens is formed in a meniscus shape at a paraxial region thereof. The seventh lens is formed in a meniscus shape at a paraxial region thereof. The seventh lens has a specific focal length. The second lens is disposed away from the third lens by a specific distance.

Abstract: An imaging lens includes a first lens; a second lens; a third lens; a fourth lens; a fifth lens; a sixth lens; and a seventh lens, arranged in this order from an object side to an image plane side. The first lens is formed in a meniscus shape at a paraxial region thereof. The third lens is formed in a shape so that a surface thereof directing to the image plane side is concave at a paraxial region thereof. The fourth lens is formed in a meniscus shape at a paraxial region thereof. The seventh lens has a specific focal length.