University of Fukui

Seiren Kst Corp.

Akira Nakao

Toshio Katsuyama

Shoji Yamada

Susumu Yonezawa

Akira Himeno

Koichi Horii

Hitoshi Higuchi

An optical multiplexer includes a first and a second optical waveguides, and a multiplexing unit. The first and second optical waveguides have a first and a second mode coupling regions being proximate to each other with a predetermined gap width, the optical waveguides in the coupling regions form the multiplexing unit. Light transfers between the optical waveguides in the first and second mode coupling regions, first light in the optical waveguide in the first mode coupling region and second light in the optical waveguide in the first or second mode coupling regions having the wavelength different from the first light are multiplexed to one of the waveguides in the mode coupling regions, and the core cross-section of the optical waveguide at least in the first and second mode coupling regions in the first and second optical waveguides is asymmetric in the height direction.

Optical multiplexer and manufacturing method for the same

A retinal scanning display device including an optical system emits laser light to a pupil of a user, an optical multiplexer individually receives types of laser light having different wavelengths emitted from a plurality of semiconductor lasers, which combines the types of laser light coaxially to output the combined laser light. On the optical multiplexer, a beam shaper shapes the combined laser light into a light beam having a predetermined divergence or convergence angle, and a direction-of-emission changer changes image signal corresponding to an image to be formed, the direction of emission of the light beam output through the beam shaper within at least a plane intersecting the direction of emission. Then, an optical engine formed with the semiconductor lasers, the optical multiplexer, the beam shaper and the direction-of-emission changer guides the laser light emitted from the direction-of-emission changer to the position of the pupil of the user.

Image display device using retinal scanning display unit and image display system

An optical multiplexer reduced in background light and reduced in size is provided. The optical multiplexer takes a plurality of light beams having different wavelengths as input from respective waveguides, and outputs multiple light obtained by multiplexing the plurality of light beams by a directional coupler. Background light is reduced by a reflection groove which reflects excess light outputted from a discard port of the directional coupler, and downsizing of the optical multiplexer is achieved.

Optical multiplexer reduced in background light

An optical multiplexer and an optical multiplexing method capable of multiplexing light of four or more types of wavelengths are provided. An optical multiplexer capable of multiplexing light of a plurality of wavelengths includes a plurality of coupling parts each including a pair of main entrance paths, a pair of main exit paths, and a main coupler arranged between the main entrance paths and the main exit paths, the main coupler causing light entering from the main entrance paths to be coupled and exit from the main exit paths, in which one of the main entrance paths of the coupling parts is joined to one of the main exit paths of anther coupling parts and the main coupler has coupling length different from at least one other main coupler.

Optical multiplexer and optical multiplexing method

Provided is a light beam emission device and a light beam projection device, that are downsizable, have a simple configuration, and simplify complicated processing of video signals, such as the timing adjustment of video output signals, without generating color irregularity. The devices include: a plurality of light sources; and a condensing member. A range in the light source array direction, in which emission spots of the light beams emitted from the plurality of light sources respectively exist, is within a size in the array direction of a light beam, immediately after the light beam emitted from an emission spot located most closely to the center of the plurality of light sources, with respect to the condensing member, passed through the condensing member.

Light beam emission device and light beam projection device equipped therewith

To provide a multiplexer that makes it possible to achieve a reduction in size and that minimizes the influence of the expansion of laser light on a multiplexing unit. A multiplexer is provided with a plurality of waveguides, multiplexing units that are provided at an intermediate location within the waveguides, and laser light sources, wherein: the first multiplexing unit is arranged at a position that is closest to the laser light sources; and the laser light sources that have an optical axis at a position that is separated from the transmission axis of the visible light that is introduced into the first multiplexing unit are arranged so that the optical axis is inclined with respect to the transmission axis and the outer periphery of laser light that expands at a predetermined expansion angle passes in front of the first multiplexing unit.

Growing community of inventors

Fukui, Japan

Akira Nakao