Kuraray Co., Ltd.

Kurarayco., Ltd.

Atsushi Uchida

Masaru Karai

Junji Watanabe

Masashi Hirai

Keisuke Ikeda

Koji Ishida

The present invention provides a diffuser plate in a simple structure capable of achieving optical properties with less luminance irregularity and color irregularity and good quality of appearance. A diffuser plate is a diffuser plate where a plurality of microlenses are placed on a principal surface, shapes of the plurality of microlenses along a cross-section perpendicular to the principal surface are different from one another and do not have an axis of symmetry. A method for designing the diffuser plate includes steps of determining a specific reference microlens; placing the reference microlens on the principal surface; forming a specific phase modulation shape; and determining a shape of the plurality of microlenses by combining the specific reference microlens and the specific phase modulation shape.

Diffuser plate and method for designing diffuser plate

Provided is a diffuser plate that makes it possible to mitigate unevenness of luminance or unevenness of color while suppressing speckle noise of transmitted light or reflected light. The diffuser plate of the present invention includes a microlens array having a structure that creates an optical path length difference for incident light or reflected light, the microlenses having the same effective diameter. The microlens array constitutes a basic block structure in which periodic arrangement is provided with a period of an integer multiple of the effective diameter, a two-dimensional second periodic structure having a period that is N times the period of the microlens array in the basic periodic structure is configured by a repetitive arrangement of the basic blocks, and the microlenses are set to create an optical path length difference based upon a specific arrangement within the basic block structure.

Diffuser plate

A diffuser plate includes a plurality of fine structures having two or more types of lens functions arranged on a main surface. Intensity of diffused light within a desired diffusion angle range is substantially uniform, and the diffuser plate satisfies a relation of P&#xd7;P&#xd7;Sk&#x2264;400 [&#x3bc;m], where P is an average pitch of the plurality of fine structures, Sk is a standard deviation of relative luminance of the plurality of fine structures in their front directions, P&#x2264;200 [&#x3bc;m], and Sk&#x2265;0.005. Thus, it is possible to provide a diffuser plate having a simple structure capable of achieving optical properties with little luminance and color unevenness and excellent appearance quality when an image is projected.

The present invention provides a diffuser plate whose luminance of emission light emitted from a microlens is even in a diffusion range. The diffuser plate comprises a projection side main surface, an emission side main surface, and a fine structure having a plurality of microlens shape parts with a microlens-like shape. A numerical aperture NA of the projection light is greater than 0 and 0.140 or less. An incident angle &#x3b8;i formed by an optical axis of the projection light at the microlens shape part and a normal of the projection side main surface intersecting with each other is in a range of 0 to 50 degrees. At least one of the plurality of microlens shape parts emits the emission light at an emission angle &#x3b8;o formed by the optical axis of the emission light and the normal of the projection side main surface intersecting with each other.

Diffuser plate and projection-type image displaying device

A diffuser plate capable of achieving excellent appearance quality when an image is projected. A transmissive diffuser plate including a microlens angle modulation distribution group provided on at least one of a light incident surface and a light emitting surface is provided. A microlens angle modulation distribution group includes a plurality of microlenses and an angle modulation part having an angle modulation distribution for angle-modulating a direction of main light emitted from each of the plurality of microlenses. When a ratio &#x3bb;/P of a wavelength &#x3bb; [&#x3bc;m] of the main light to an average arrangement period P [&#x3bc;m] of the microlens is denoted by &#x3b8; [rad], and when the direction of the main light emitted from each of the plurality of microlenses is modulated by a modulation angle &#x3b1; [rad], a ratio &#x3b1;/&#x3b8; of the modulation angle &#x3b1; to &#x3b8; satisfies 0.1&#x3c;&#x3b1;/&#x3b8;&#x3c;10.0.

Transmissive diffuser plate having a microlens angle modulation distribution group

A composite diffuser plate capable of inhibiting luminance unevenness from occurring locally is described. The composite diffuser plate includes a first diffuser plate and a second diffuser plate arranged in this order from an incident side. At least one of the first diffuser plate and the second diffuser plate is composed of a random microlens array including multiple microlenses. The microlenses include a plurality of parameters defining a lens shape. At least one of the plural parameters is randomly distributed. The random microlens array causes a phase difference to be generated in transmitted light.

Composite diffuser plate

The present invention provides a diffuser plate and a method for producing a diffuser plate that can improve variations in luminance of transmitted light or reflected light in a simple structure and that enable easy design and production. The diffuser plate according to the present invention is a diffuser plate where a plurality of microlenses are placed on a principal surface, wherein a phase difference generation part is inserted between the plurality of microlenses and the principal surface, the plurality of microlenses have two or more types of lens shapes, and the number of microlenses having the two or more types of lens shapes is determined so that a quantity ratio of the two or more types of lens shapes is a specific value, each of the lens shape types is selected corresponding to each of coordinates on the principal surface in which centers of undersurfaces of the plurality of microlenses are placed, and an angle range in which the diffuse light intensity is substantially uniform is in a range of +10% to &#x2212;10% of a desired angle range.

Diffuser plate and method for producing diffuser plate

The present invention provides a method for designing a light diffusion pattern with which a light diffusion pattern to exhibit desired light diffusion properties can be designed depending on a few systematic procedures. The method includes a lens data preparation step of preparing lens data having desired light diffusion properties, a placement step of placing a plurality of lens data () prepared in the lens data preparation step in a predetermined region (), a cutting step of, when an overlap () of lenses () occurs in the placement step, cutting out a part () of a lens shape to eliminate the overlap (), and a repositioning step of replicating a shape of the cutout part () and repositioning it to another place.

Growing community of inventors

Kamisu, Japan

Atsushi Uchida