Abstract: Provided is a method for manufacturing an optical element, the method including: an electrode forming step of forming metal films on the plus z face and minus z face of a ferroelectric substrate to fabricate electrodes; a periodic electrode forming step of forming the metal film on the plus z face into a periodic electrode; a polarization reversal forming step of applying a voltage between the periodic electrode and the electrode on the minus z face to form polarization-reversed regions in the ferroelectric substrate; a surface treating step of removing the electrode, the periodic electrode, and surface layers on the plus z face and minus z face of the ferroelectric substrate; and an annealing step of applying predetermined heat to the ferroelectric substrate having the surface layers removed therefrom.

Abstract: Provided is a method for manufacturing a wavelength conversion element 3 for converting a fundamental wave into a second harmonic wave, the method including the aging step (step 4) of irradiating a nonlinear optical crystal substrate 1 with a first light beam 4 having the same wavelength as the fundamental wave until the amount of variation per unit time in the phase matching temperature becomes a predetermined reference value or smaller while keeping the temperature of the nonlinear optical crystal substrate 1 at around the phase matching temperature after forming a periodical polarization-reversed structure in the nonlinear optical crystal substrate 1 (step 2).

Abstract: A display device (100) of the present invention has a first switch (3) and a second switch (4) on an upper surface of its casing, and includes a control circuit (18) for controlling the first switch (3) and the second switch (4) and a light source (19) inside the casing. The control circuit (18) performs control so that the light source (19) is turned on when the second switch (4) is pressed after a predetermined period of time has passed from when the first switch (3) was pressed. Thereby, the display device (100) of the present invention prevents entering of a person into a projection area before projection of video, and controls inadvertent start-up.

Abstract: A wavelength conversion element (1) for converting fundamental waves (2) into harmonic waves (3) having wavelengths shorter than those of the fundamental waves (2), the wavelength conversion element (1) includes a low refractive index region (4) having a refractive index lower than those of the other regions. The low refractive index region (4) is formed in the forming region of a thermal lens and is desirably formed between the light outputting side and the light collecting position of the fundamental waves (2). The wavelength conversion element (1) of the present invention includes the low refractive index region (4) that reduces a refractive power generated by the thermal lens, thereby achieving a stable output even with a high output. An apparatus for generating short wavelength light by using the wavelength conversion element (1) includes a fundamental wave light source and a light collecting optical system (5) that collects the fundamental waves.

Abstract: A wavelength converter is provided with an infrared light source (1) for emitting a fundamental wave having a wavelength of 2000 nm or shorter, a wavelength conversion element (3) composed of a nonlinear optical crystal having a periodical polarization reversal structure and adapted to convert a fundamental wave emitted from the infrared light source (1) into a harmonic wave, and a heater (4) for heating the wavelength conversion element (3). The period of the polarization reversal structure is designed so that a quasi phase matching temperature of the fundamental wave and the harmonic wave is 40° C. or higher. The heater (4) heats the wavelength conversion element (3) to a temperature at which quasi phase matching is established, and the nonlinear optical crystal contains a lithium niobate or lithium tantalate including at least any one of additives Mg, In, Zn and Sc as a main component. Thus, optical damage can be suppressed and visible light absorption attributed to ultraviolet light can be reduced.

Abstract: Upon obtaining green light as wavelength converted light by causing infrared light to be incident on a wavelength conversion element, the absorption of the green light occurs due to the generation of ultraviolet light as sum-frequency light of the infrared light and the green light in the wavelength conversion element and the destruction of a crystal composing the wavelength conversion element occurs due to heat generated at this time. In a laser wavelength converter of the present invention, a condensed position of the infrared light in the wavelength conversion element is deviated from a position assumed to be optimal when the influence of the generated heat is ignored. Consequently, crystal destruction is suppressed, a high-efficiency wavelength conversion is enabled and high-output wavelength converted light exceeding several watts, which was difficult to attain in conventional wavelength conversion elements, is attained.

Abstract: A semiconductor laser light source emits a laser beam for pumping. An optical resonator includes a solid laser crystal to be excited by the incident of a laser beam to oscillate a fundamental wave and a pair of fundamental wave reflective coats arranged at the opposite sides of the solid laser crystal. A wavelength conversion element converts the fundamental wave into a plurality of harmonics. The wavelength conversion element is so arranged in the optical resonator that the optical axis of at least one of the plurality of harmonics, generated in the optical resonator is made different from that of the fundamental wave and the at least one harmonic whose optical axis is made different is output substantially in the same direction as the other harmonic. By this construction, it is possible to stabilize a harmonic output and utilize a plurality of harmonics without increasing the number of parts.

Abstract: A display for illuminating a liquid crystal display panel with laser light of uniform light quantity distribution, and an illuminator for irradiating with laser light of uniform light quantity distribution. The display includes a liquid crystal display panel (204), laser light sources (205, 206, 207) emitting laser light having wavelengths of green, red, and blue colors, a waveguide plate (201) arranged at the back side of the liquid crystal display panel (204) and performing multiple reflection of laser light, and a diffusion plate (202) arranged at the back side of the waveguide plate (201), diffusing laser light propagating in the waveguide plate (201) and emitting the light toward the liquid crystal display panel (204).

Abstract: A laser light source device, which is capable of multi-wavelength oscillation, includes a laser light source; and a laser cavity including (i) a fiber, (ii) a first fiber grating provided at a side of the fiber toward the laser light source and having a plurality of reflection peaks, and (iii) a second fiber grating provided at a light emission end of the fiber and having a plurality of reflection peaks. Further, the laser light source includes a wavelength converter converting a fundamental wave emitted from the laser cavity into a harmonic wave; a reflection wavelength varying unit shifting reflection wavelengths of the reflection peaks of the second fiber grating; and a controller controlling phase matching conditions of the wavelength converter. As a result, intervals between adjacent reflection peaks of the first fiber grating are different from those between adjacent reflection peaks of the second fiber grating.

Abstract: A 2-dimensional beam scan unit reflects emission beams from a red laser light source, a green laser light source and a blue laser light source and scans in a 2-dimensional direction. Diffusion plates diffuse the respective light beams scanned in the 2-dimensional direction to introduce them to corresponding spatial light modulation elements. The respective spatial light modulation elements modulate the respective lights in accordance with video signals of the respective colors. A dichroic prism multiplexes the lights of the three colors after the modulation and introduces the multiplexed lights to a projection lens so that a color image is displayed on a screen. Since the 2-dimensional light emitted from the beam scan unit is diffused to illuminate the spatial light modulation element, it is possible to change the optical axis of the beam emerging from the light diffusion member for irradiating the spatial light modulation element moment by moment, thereby effectively suppressing speckle noise.

Abstract: A wavelength conversion laser device includes a laser light source which emits a laser beam, two reflective surfaces which reflect therefrom a laser beam, a wavelength converter provided between the two reflective surfaces, which converts a laser beam into a wavelength-converted laser beam, and condensing optics which condense the laser beams to be injected between the two reflective surfaces, wherein at least one of the two reflective surfaces has a curvature for reflecting a laser beam to be re-injected into the wavelength converter between the two reflective surfaces repeatedly while forming multi paths of laser beams injected into the wavelength converter at different incident angles, and the condensing optics are arranged to disperse beam waists of the laser beams in the wavelength converter, which reciprocate between the two reflective surfaces.

Abstract: A projector system is provided with at least one projector mobile in a specified space and adapted to project a video to a projection area included in the specified space in accordance with inputted video information, a plurality of position sensors each including a position detecting section for detecting a positional relationship of the projector with the projection area and arranged in a specified positional relationship with the specified space, and a controller for controlling a video to be projected from the projector to the projection area based on detection results by the position detecting sections of the plurality of position sensors.

Abstract: There is provided a light source device which can miniaturize a two-dimensional image display device as small as possible. The light source device is provided with three coherent light sources (11a), (11b), and (11c) corresponding to red, blue, and green; prisms (12a) and (12c) for reflecting lights emitted from the coherent light sources (11a) and (11c); and a diffraction part (20) comprising a single volume hologram on which plural gratings are multiply-formed, which gratings diffract the light emitted from the coherent light source (11b), and the lights that are emitted from the coherent light sources (11a) and (11c) and reflected by the prisms (12a) and (12b) so that these lights propagate in the same optical path.

Abstract: A light source of the present invention includes: a semiconductor light emitting device which has a light emitting face and emits light from part of the light emitting face; a container which has a light transmitting window for transmitting the light and accommodates the semiconductor light emitting device; and a gettering portion for performing gettering of a material containing at least one of carbon and silicon. The gettering portion is positioned, in the container, in a region other than the part of the light emitting face of the semiconductor light emitting device.

Abstract: A 2-dimensional beam scan unit reflects emission beams from a red laser light source, a green laser light source and a blue laser light source and scans in a 2-dimensional direction. Diffusion plates diffuse the respective light beams scanned in the 2-dimensional direction to introduce them to corresponding spatial light modulation elements. The respective spatial light modulation elements modulate the respective lights in accordance with video signals of the respective colors. A dichroic prism multiplexes the lights of the three colors after the modulation and introduces the multiplexed lights to a projection lens so that a color image is displayed on a screen. Since the 2-dimensional light emitted from the beam scan unit is diffused to illuminate the spatial light modulation element, it is possible to change the optical axis of the beam emerging from the light diffusion member for irradiating the spatial light modulation element moment by moment, thereby effectively suppressing speckle noise.

Abstract: A wavelength conversion element is provided with a substrate including a nonlinear optical single crystal having a periodically poled structure, wherein a visible light transmittance of the substrate is 85% or higher when ultraviolet light is irradiated to the substrate. Further, a laser light having an average output of 1 W or more is outputted by shortening a wavelength of inputted laser light having a wavelength of 640 nm to 2000 nm. By improving visible light transmission characteristics when the ultraviolet light is irradiated in this way, a breakdown of crystal can be prevented and a stabilization of output characteristics at high output can be realized. As a result, an absorption of green light induced by ultraviolet light can also be suppressed and a saturation of output and the breakdown of crystal can be avoided.

Abstract: A wavelength conversion laser is provided with a pair of fundamental wave reflecting surfaces for reflecting a fundamental wave to define a plurality of fundamental wave paths passing a wavelength conversion element at different angles, and a control unit for controlling wavelength conversion efficiencies so that the wavelength conversion efficiency on a specific one of the plurality of fundamental wave paths extending in different directions between the pair of fundamental wave reflecting surfaces is highest.

Abstract: A short wavelength light source includes a wavelength conversion element having an incident surface, on which a fundamental wave is incident, and an output surface, from which a harmonic wave is outputted. The wavelength conversion element converts the fundamental wave into the harmonic wave. In addition, the wavelength conversion element includes a holder holding the wavelength conversion element, wherein the wavelength conversion element has a specific region on a light output side, which is arranged so as to suppress variations in phase matching condition between the fundamental wave and the harmonic wave resulting from heat generated by absorbing the harmonic wave during a wavelength conversion.

Abstract: A video projector includes a laser projection unit that has linear-polarization short-wavelength laser light sources and emits laser lights from the laser light sources, a lens system that collects the laser lights from the laser projection unit, a liquid crystal cell that spatially modulates the collected laser lights, a camera shake correcting optical system that is capable of translating vertically and horizontally on a plane that is perpendicular to the optical axis of the laser projection unit, a prism that transmits the laser lights from the liquid crystal cell and branches the light reflected by the screen, and a camera device that can observe or capture the video image that is branched by the prism. The present invention provides a video projector that can prevent the camera shake and can be held in hands.

Abstract: A wavelength conversion laser device includes a laser light source which emits a laser beam, two reflective surfaces which reflect therefrom a laser beam, a wavelength converter provided between the two reflective surfaces, which converts a laser beam into a wavelength-converted laser beam, and condensing optics which condense the laser beams to be injected between the two reflective surfaces, wherein at least one of the two reflective surfaces has a curvature for reflecting a laser beam to be re-injected into the wavelength converter between the two reflective surfaces repeatedly while forming multi paths of laser beams injected into the wavelength converter at different incident angles, and the condensing optics are arranged to disperse beam waists of the laser beams in the wavelength converter, which reciprocate between the two reflective surfaces.