Diffuser plate
AssigneeKuraray Co., Ltd.
InventorsAtsushi Uchida, Masaru Karai, Junji Watanabe
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Abstract
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×P×Sk≤400 [μm2], 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≤200 [μm], and Sk≥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.
Claims12
A diffuser plate, comprising:
- a microlens array comprising a plurality of microlenses 1 to n having two or more types of lens functions arranged on a main surface of a substrate,
- wherein
- the microlens array covers an area having a front side, a rear side, a left side, and a right side each of which are coincident with the directionality of the diffuser plate,
- intensity of diffused light within a target diffusion angle range is substantially uniform,
- the diffuser plate satisfies a relation of P×P×Sk≤400 [μm2], where P is an average pitch of the plurality of microlenses, Sk is a standard deviation of relative front luminances of microlenses 1 to n in the microlens array, and 0<P≤200 [μm], and Sk≥0.005,
- the shapes of the plurality of microlenses of the microlens array are a combination of a phase modulation shape and shapes of a plurality of reference microlenses,
- the shapes of the plurality of reference microlenses are microlenses each having a symmetric axis, and
- the phase modulation shape is a continuously changing three-dimensional curved surface without a symmetric axis.
Dependencies are inferred from the claim text.