Abstract: A display device includes a light guide plate including a hologram element and a light emitter that emits light to the light guide plate. In addition, the light emitter includes a light source that emits light, and a first optical body including a plurality of first lenses capable of adjusting a contour of the light emitted by the light source. An outline of each of the plurality of first lenses is analogous to a shape of the hologram element.

Abstract: An optical modulator is a Mach-Zehnder-type optical modulator having a substrate and an optical waveguide layer including a lithium niobate film formed on the substrate. The optical waveguide layer includes a plurality of flat portions and n ridge portions arranged between the flat portions to be adjacent, where n is two or more. Each of the n ridge portions includes a main waveguide to which visible light is input, a first multimode interference waveguide through which the main waveguide is branched into a first and a second optical branch waveguide, and a second multimode interference waveguide through which the first and the second optical branch waveguide are coupled to form a coupling waveguide. Visible light beams having different wavelengths are input to the n ridge portions. The first multimode interference waveguide and the second multimode interference waveguide have shorter lengths when input light having a longer wavelength is transmitted.

Abstract: The optical coupler is a multimode interference type optical coupler that couples a plurality of laser lights of different wavelengths. The optical coupler includes an optical coupling main body, two input taper portions which are tapered input ports that are disposed on the input side of the optical coupling main body and of which the width of each becomes narrower as it is away from a connection end with the optical coupling main body, and one output taper portion which is a tapered output port that is disposed on the output side of the optical coupling main body and of which the width becomes narrower as it is away from a connection end with the optical coupling main body.

Abstract: This optical coupler includes a plurality of light input ports to which a plurality of visible light beams can be input, a light output port capable of coupling all of the plurality of visible light beams and outputting coupled light, an optical coupling portion to which a light-input-side optical waveguide and a light-output-side optical waveguide are connected, and at least one high-order mode removal portion provided to remove a high mode with respect to each of the plurality of visible light beams. The optical coupling portion and each high-order mode removal portion are arranged so that each of the plurality of visible light beams passes through only a high-order mode removal portion for visible light or passes through only the high-order mode removal portion for the visible light and a high-order mode removal portion for visible light having a shorter wavelength than the visible light.

Abstract: A Y-branch type optical coupler includes an optical coupling part to which a plurality of input-side optical waveguides through which the plurality of lights propagate, and one output-side optical waveguide are connected, wherein the optical coupling part has an isosceles trapezoid shape of which the width is narrowed in a taper shape at a first angle ? from the input side to the output side (a traveling direction of light) in a plan view, at least two input-side optical waveguides among the plurality of input-side optical waveguides are disposed symmetrically with respect to a symmetry axis of the isosceles trapezoid, are inclined at a second angle ? that is different from the first angle ?, and are connected to a lower bottom portion of the isosceles trapezoid, and the difference between the first angle and the second angle is 0.9° or more and 14.8° or less.

Abstract: An optical waveguide element includes: an optical waveguide having a ridge part and a slab part having a thickness less than the ridge part. The optical waveguide includes: a first waveguide having a first ridge with and a first slab film thickness; a second waveguide having a second ridge width and a second slab film thickness; a first intermediate waveguide connected to the first waveguide and having a third ridge width and the first slab film thickness; and a second intermediate waveguide connected to the second waveguide and having a fourth ridge width and the second slab film thickness. The first waveguide, the first intermediate waveguide, the second intermediate waveguide, and the second waveguide are arranged in this order; the second slab film thickness is larger than the first slab film thickness; and the third ridge width is larger than the fourth ridge width.

Abstract: An optical coupler of the present invention is an optical coupler that couples laser lights of three different wavelengths, and includes a two-stage MMI type optical coupler in which a first MMI type optical coupling part and a second MMI type optical coupling part are connected from the input side, and the width of the first MMI type optical coupling part is wider than the width of the second MMI type optical coupling part.

Abstract: A visible light modulation device includes a light source part having a plurality of optical semiconductor devices configured to emit light with a visible light wavelength of 400 nm to 700 nm, and a light modulation output part having three Mach-Zehnder type optical waveguides consisting of a convex fabricated lithium niobate film, and being configured so that light emitted from each of the plurality of optical semiconductor devices is incident on the corresponding Mach-Zehnder type optical waveguide.

Abstract: An optical coupler includes: light input ports on a first side surface; monitoring light output ports on a second side surface; one light output port on a third side surface; and multimode-interference-type optical coupling parts, a first multimode-interference coupling part is connected to a first light-input-side waveguide on the input side, and to a first monitoring-light-output-side waveguide and a first connecting waveguide on the output side, the second multimode-interference coupling part is connected to a second light-input-side waveguide and the first connecting waveguide on the input side, and to a second monitoring-light-output-side waveguide and a second connecting waveguide on the output side, and the third multimode-interference coupling part is connected to a third light-input-side waveguide and the second connecting waveguide on the input side, and connected to a third monitoring-light-output-side waveguide and a light-output-port-connected waveguide on the output side, and the monitoring-ligh

Abstract: This optical coupler for coupling a plurality of visible light beams having different wavelengths includes: a substrate made of a material different from lithium niobate; and an optical coupling function layer formed on a main surface of the substrate. The optical coupling function layer includes: two multimode-interference-type optical coupling parts; optical-input-side waveguides and an optical-output-side waveguide connected to one multimode-interference-type optical coupling part, and optical-input-side waveguides and an optical-output-side waveguide connected to the other multimode-interference-type optical coupling part. The multimode-interference-type optical coupling parts, the optical-input-side waveguides, and the optical-output-side waveguides are made of a lithium niobate film.

Abstract: An optical system includes a light guide member and a prism. The light guide member has: an incident surface on which light is incident; and a first surface and a second surface facing each other. The second surface is a light emergent surface. The prism is provided for the first surface and reflects, toward the second surface, the light passing inside the light guide member. The light guide member includes a direct optical path, along which the light that has entered the light guide member through the incident surface is directly reflected from the prism and allowed to emerge from the second surface.

Abstract: Provided is a head-up display including a backlight configured to emit light, a light-diffusion member through which the light emitted by the backlight is transmitted, a Fresnel lens through which the light transmitted through the light-diffusion member is transmitted, a display screen through which the light transmitted through the Fresnel lens is transmitted, and a mirror that reflects the light transmitted through the light-diffusion member toward a target space.

Abstract: An optical system includes a light guide member having a light incident surface, a first surface, and a light emergent surface facing the first surface; and a prism provided in the first surface for reflecting light passing inside the light guide member towards the light emergent surface. The light guide member includes a direct optical path, along which the light that has entered the light guide member through the incident surface is directly reflected from the prism and allowed to emerge from the light emergent surface. At least one of the first surface or the light emergent surface includes a luminous intensity distribution control member configured to control a luminous intensity distribution of light to be extracted from the light emergent surface. The luminous intensity distribution control member includes a Fresnel lens.

Abstract: A projection device includes: a plurality of light sources arranged in a first direction; a spatial modulation element that modulates incident light into image information and emits the image information; a lens that changes an optical path of light emitted from each of the plurality of light sources such that the light emitted from each light source reaches substantially the same region of an incident surface of the spatial modulation element; and a first reflective optical member that deflects the light emitted from the lens toward the spatial modulation element, the first reflective optical member having a shape that reflects light emitted from the lens so as to be incident on an arbitrary point on the incident surface of the spatial modulation element at a predetermined reference incident angle.

Abstract: A head-up display includes a liquid-crystal panel including a display screen provided at a front surface thereof, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion structure between the liquid-crystal panel and the Fresnel lens, a backlight that emits light toward the Fresnel lens, a light-transmissive member between the backlight and the Fresnel lens, a body part accommodating the Fresnel lens, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space. The body part has a step-shaped structure including a first step surface and a second step surface, the first and second step surfaces are oriented in the same direction as the front surface of the liquid-crystal panel. The first step surface is located on the liquid-crystal panel side from the second step surface.

Abstract: A projection device includes: a plurality of light sources arranged in a first direction; a spatial modulation element that modulates incident light into image information and emits the image information; a lens that changes an optical path of light emitted from each of the plurality of light sources such that the light emitted from each light source reaches substantially the same region of an incident surface of the spatial modulation element; and a first reflective optical member that deflects the light emitted from the lens toward the spatial modulation element, the first reflective optical member having a shape that reflects light emitted from the lens so as to be incident on an arbitrary point on the incident surface of the spatial modulation element at a predetermined reference incident angle.

Abstract: Provided is a head-up display including a display system that has a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, and a backlight that emits light toward the Fresnel lens. The head-up display also includes a first mirror that reflects light from the display system, a second mirror that reflects light from the first mirror, and a control circuit that controls the liquid-crystal panel, where a center of the second mirror is closer to a center of the control circuit than a center of the display system in a direction connecting a center of the first mirror and the center of the second mirror.

Abstract: Provided is a head-up display including a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion structure between the liquid-crystal panel and the Fresnel lens, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space, where the light-diffusion structure is thinner than the Fresnel lens, and the light-diffusion structure has a thickness equal to or smaller than 300 ?m.

Abstract: An optical modulation element is provided with a substrate, a waveguide layer formed on the substrate, a dielectric layer formed on the waveguide layer, and an electrode formed on the dielectric layer. An outer peripheral end portion of the dielectric layer has an offset area positioned inside an outer peripheral end portion of the substrate. In at least a part of the offset area, a distance from the outer peripheral end portion of the substrate to the outer peripheral end portion of the dielectric layer is equal to or less than a distance from the outer peripheral end portion of the substrate to the outer peripheral end portion of the electrode.

Abstract: Provided is a head-up display including a liquid-crystal panel including a display screen, a Fresnel lens which is on an opposite side of the liquid-crystal panel from the display screen, a light-diffusion structure between the liquid-crystal panel and the Fresnel lens, a backlight that emits light toward the light-transmissive member, and a mirror that forms a virtual image corresponding to an image displayed on the display screen of the liquid-crystal panel, in a target space, where the light-diffusion structure includes a plurality of fine particles and an average particle size of the plurality of fine particles is equal to or smaller than 20 um.