Abstract: The present invention relates to a manufacturing method of a display apparatus having a display portion that is made of dot-like reflection portions. The method comprising steps of: heating at least one of a blade portion of a machining tool and a light guide plate, descending the machining tool along a specific formation direction of the blade portion all through this descending step to press the blade portion into a back surface of the light guide plate, ascending the machining tool along a specific formation direction of the blade portion all through this ascending step to pull out the blade portion from the light guide plate, moving the machining tool horizontally, and arranging at least one light source along at least one edge face of the light guide plate. The steps of descending, ascending, and horizontally moving the machining tool are performed repeatedly to form the dot-like reflection portions.

Abstract: A method of manufacturing a display apparatus that includes: a light guide plate; and a light source provided on an edge face of the light guide plate. In the light guide plate, a display portion made of a dot-like reflection portion with a reflection surface for reflecting a light beam emitted from the light source to a surface is formed. In the display portion, the reflected light beam from the dot-like reflection portion is configured to be visible. This display apparatus manufactured by the method is excellent in transparency, has a display portion visually recognizable with ease, and can be manufactured at a low cost.

Abstract: This display apparatus 10 includes: a light guide plate 1; and a light source 6 provided on an edge face 1a of the light guide plate 1. In the light guide plate 1, a display portion 3 made of a dot-like reflection portion 2 with a reflection surface 2a for reflecting a light beam emitted from the light source 6 to a surface 1b is formed. In the display portion 3, the reflected light beam from the dot-like reflection portion 2 is configured to be visible. This display apparatus 10 is excellent in transparency, has a display portion visually recognizable with ease, and can be manufactured at a low cost.

Abstract: An optical fiber amplifier comprises an optical fiber for light loss which is provided in a later stage than an optical fiber amplification section or midway therein, the amount of light absorption and the wavelength dependency of the absorption of the optical fiber changing according to the power of input light; whereby the optical fiber amplifier can maintain flat gain in a wide wavelength band, the gain flatness not changing over a wide dynamic range and being maintained irrespective of variation in the power of input signal light.

Abstract: In an optical amplifier using a rare earth element-doped optical fiber such as an erbium-doped optical fiber, a variation of amplification gain resulting from temperature change is suppressed and the gain-temperature characteristic is enhanced. Moreover, the quantity of temperature compensation in the gain is easily adjustable. Light from an excitation light source is input to an optical fiber for optical amplification comprising a rare earth element-doped optical fiber, via a temperature compensation optical fiber comprising a rare earth element-doped optical fiber such as an erbium-doped optical fiber. By changing the length of this temperature compensation optical fiber, the quantity of temperature compensation is finely adjusted.

Abstract: An optical fiber amplifier comprises an optical fiber for light loss which is provided in a later stage than an optical fiber amplification section or midway therein, the amount of light absorption and the wavelength dependency of the absorption of the optical fiber changing according to the power of input light; whereby the optical fiber amplifier can maintain flat gain in a wide wavelength band, the gain flatness not changing over a wide dynamic range and being maintained irrespective of variation in the power of input signal light.

Abstract: An oxygen sensor device is disclosed having a glass dome fluid-tightly connected at its circumferential base edge to one surface of an oxygen conductive solid electrolyte plate to form a diffusion chamber defined by the glass dome and the solid electrolyte plate. The diffusion chamber may be vacant, or may have a porous inorganic material packing layer fixedly disposed in the entire space thereof. Alternatively, the diffusion chamber may have a porous inorganic material semi-packing layer fixedly disposed in an upper portion thereof remote from the electrolyte plate, while leaving vacant the remainder of the chamber. The oxygen sensor device is advantageous from the viewpoints of miniaturization, power consumption saving and reliability.