Abstract: Image recording as long as possible during one activity is required in deep sea exploration. Necessity of multi-directional image recording, optical and chemical observations and probing of mineral resources of seabed are also increased. There is no underwater exploration device enable these requirements. It is disclosed that at least one battery-driven underwater exploration body having three pressure-resistant hollow glass spheres for housing an image capturing device, an illumination device, a recording device, an acoustic communication device and a control device controlling thereof and at least one battery body having an approximately the same shape and structure as the underwater exploration body are connected with each other by a connecting tool to provide the connectedly-formed underwater exploration device.

Abstract: In a pressure-resistant glass sphere used for exploration of deep sea, ocean floor or the like, it is an important issue to reduce weight and increase a floating force while keeping pressure resistance capable of withstanding high water pressure of deep sea or the like and being used repeatedly. A pressure-resistant glass sphere of the present invention is composed of a pair of glass-made hollow hemispherical bodies, wherein the glass-made hollow hemispherical bodies are joined with each other at ground joint surfaces located on an equatorial plane of the pressure-resistant glass sphere so that the ground joint surfaces serve as a joining surface, and characterized in that a thickness of a spherical shell of the glass-made hollow hemispherical bodies is thicker at an equatorial plane portion than the portion other than the equatorial plane portion having a predetermined width from the ground joint surfaces.

Abstract: To provide a photovoltaic device and a light condensing device having a high condensing rate which can be manufactured easily and at low cost. This light condensing device is provided with: a light-guiding subtract for causing light to propagate between a rear-side surface and a front-side surface for receiving light from a light source; a reflective layer for light guiding, in which a reflection-type hologram is formed for reflecting light incident at a first incidence angle less than the critical angle of the light-guiding substrate at a reflection angle greater than the critical angle, the reflective layer being provided to the rear-side surface; and an emission window for causing light incident at a second incidence angle equal to or greater than the critical angle to be emitted from the light-guiding substrate, the emission window being provided to the front-side surface and/or the rear-side surface.

Abstract: The present invention provides a housing for use in an underwater video camera which does not require a window comprised from a thick parallel flat plate and large scale pressure resistant sealing container and which can take 3D images in deep water or hadal zone. A housing for an underwater video camera formed from a glass hollow sphere for housing an imaging video camera including filling a roughly spherical segmental shape correction lens to a spherical segment enclosed by a cutting plane parallel to a lens surface of an imaging lens of the imaging video camera housed inside the glass hollow sphere, the cutting plane being a flat surface facing the lens surface and an inner surface of a spherical crown of the glass hollow sphere cut out using the cutting plane.

Abstract: A glass polarizer applicable to projection-type liquid crystal displays and the like and having an excellent transmittance and extinction ratio with respect to light in the visible light region (500 nm to 600 nm) using silver halide containing glass as a starting material is provided. A glass polarizer for visible light according to the present invention is a polarizer manufactured by heating and stretching borosilicate glass in which silver halide particles are dispersed and deposited by heat treatment and reducing at least a portion of silver halide particles oriented and stretched in the glass to produce metallic silver particles. An average transmittance (T? % 500 to 600 nm) in a wavelength range of 500 nm to 600 nm of light having a polarization plane perpendicular to a longitudinal direction of metallic silver particles having shape anisotropy that is uniaxially oriented and dispersed is 75% or more and an extinction ratio in the wavelength range is 25 dB or more.

Abstract: A glass polarizer having an excellent transmittance and extinction ratio with respect to light in the visible light range including blue using silver halide containing glass as a starting material is provided. A manufacturing method according to the present invention to manufacture glass polarizers is characterized in that borosilicate glass in which silver halide particles are dispersed and deposited by heat treatment is reduced to generate metallic silver particles from at least a portion of silver halide and then, heated for stretching to generate silver halide particles oriented and stretched in the glass.