Canon Kabushiki Kaisha

Ryota Kadowaki

Yu Yamauchi

Atsushi Okuyama

Takashi Sudo

Yuya Kurata

Minoru Ohkoba

The wavelength conversion element converts a wavelength of part of an exciting light to generate a fluorescent light and thereby generate a combined light in which the fluorescent light is combined with a non-converted light whose wavelength is the same as that of the exciting light. The element includes a fluorescent body, a binder contacting the fluorescent body, and multiple diffuser particles included in the binder. A minimum particle diameter of the multiple diffuser particles is &#xbc; or more and 4 times or less of a wavelength of the fluorescent light, and a ratio of a volume of the multiple diffuser particles to a total volume of the binder and multiple diffuser particles is 25% or more and 50% or less.

Wavelength conversion element, light source apparatus and image projection apparatus

A fluorescent element includes a fluorescent light layer that converts a light flux from an LD light source into light having a different wavelength, a scattering layer, and a reflective element. The fluorescent light layer is provided between the scattering layer and the reflective element.

Optical element, light source device using the same, and projection display apparatus

Provided is the image display apparatus including: the light source which emits excitation light; a phosphor which converts the excitation light into fluorescent light and rotates; an image display element which modulates the fluorescent light; and a control unit which controls the image display element so that the image display element repeats first displaying based on an image signal and second displaying which is darker than the first displaying, at a predetermined frequency, wherein when a higher frequency of the predetermined frequency and a rotation frequency of the phosphor is represented by Fhigh, and a lower frequency thereof is represented by |Fhigh/2&#x2212;Flow|&#x3c;15.

Image display apparatus

A light source unit includes a fluorescent member configured to emit, when irradiated with excitation light, fluorescence light having a wavelength different from a wavelength of the excitation light, and a controller configured to adjust a conversion efficiency from the excitation light to the fluorescence light of the fluorescent member so that a gradient T satisfies 0.35G&#x2266;T&#x2266;0.8G in a fluorescence characteristic of the fluorescent member when a horizontal axis represents a normalized light intensity of the excitation light so that a maximum light intensity of the excitation light incident on the fluorescent member is normalized to 1, and a vertical axis represents the light intensity of the fluorescence light from the fluorescence member irradiated with the normalized light intensity of the excitation light, where G represents a gradient in the fluorescence characteristic when the normalized light intensity of the excitation light is 0.3.

Light source unit, control method thereof, and projection-type display apparatus

An optical system for image projection is disclosed which is capable of improving contrast while suppressing reduction of light amount. The optical system includes a converging optical system, and a polarization beam splitting surface transmitting an incoming light flux having a first polarization direction from the converging optical system, to introduce it to the image-forming element and causing light having a second polarization direction, of an outgoing light flux from the image-forming element, to proceed to a projection optical system. In a first cross-section parallel to a normal to the polarization beam splitting surface, the converging optical system has a configuration causing an incident angle on the splitting surface of a light ray passing through a barycenter of intensity distribution of the outgoing light flux to be larger than an incident angle thereon of a light ray passing through a barycenter of intensity distribution of the incoming light flux.

Optical system for image projection and image projection apparatus including a polarization beam splitting surface

An illumination optical system configured to guide a light flux from a light source unit onto an illuminated surface includes a compression system configured to compress the light flux at a different compression ratio in a first cross section and a second cross section which are orthogonal to each other, and a polarized light splitting unit including a polarization split surface. The second cross section includes a line normal to the polarization split surface. Where a compression ratio for compressing a light flux in the first cross section is &#x3b1;, a compression ratio in the second cross section is &#x3b2;, and an F number smaller of F numbers calculated according to a maximum angle of a light flux incident on an illuminated surface in the first and the second cross sections is Fno, the following conditions are satisfied:&#x2212;0.18*()+1.245*()&#x2212;1.260&#x3c;&#x3b1;/&#x3b2;&#x3c;1 1.4&#x2266;&#x2266;3.6.

Growing community of inventors

Saitama, Japan

Ryota Kadowaki