# US 2018/0024280 A1 · Diffuser and method for manufacturing the same

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- Number: US 2018/0024280 A1
- Document ID: US20180024280A1
- Status: Published application
- Kind: A1
- Application number: 15/723,570
- Filed: 2017-10-03
- Published: 2018-01-25
- Earliest claimed: 2015-04-06
- Assignees: Nalux Co., Ltd.
- Applicants: Nalux Co., Ltd.
- Inventors: Kazuya YAMAMOTO; Makio NISHIMAKI; Daisuke SEKI
- Web page: https://patentgrep.com/patent/US20180024280A1

## CPC

- G02B 5/0268: {characterized by the fabrication or manufacturing method}
- B29C 33/42: characterised by the shape of the moulding surface, e.g. ribs or grooves
- F21V 5/004: {using microlenses}
- B29C 33/424: {Moulding surfaces provided with means for marking or patterning (for injection moulding B29C45/372)}
- F21V 3/049: {Patterns or structured surfaces for diffusing light, e.g. frosted surfaces}
- G02B 5/0221: {the surface having an irregular structure (G02B5/0226 takes precedence)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR

## Abstract

A diffuser is provided with a recess-protrusion structure formed on a plane. When a z-axis is defined as a normal to the plane, an x-axis is defined on the plane, the x-axis is divided into plural intervals, Snx represents length of an interval nx, Sx-max and Sx-min represent the maximum and the minimum of Snx, respectively, the relationship 2<Sx-max/Sx-min holds, Snx varies on a random basis between Sx-min and Sx-max, in an xz cross section, a recess portion and a protrusion portion are formed on each of adjacent intervals along the x-axis, respectively, and when dznx represents a difference between the maximum and the minimum of z coordinate of the recess-protrusion structure in the interval nx in the xz cross section, Anx represents a ratio between dznx and Snx, Anx-max and Anx-min represent the maximum and the minimum of Anx, the relationship Ax-max/Ax-min<1.3 holds.

## Claims

### Claim 1

A diffuser provided with a recess-protrusion structure formed on a plane,
wherein when a z-axis is defined as a normal to the plane, an x-axis is defined on the plane, the x-axis is divided into plural intervals, nx represents a positive integer for identifying an interval along the x-axis, Snx represents length in the x-axis direction of an interval nx, Sx-max represents the maximum value of Snx, and Sx-min represents the minimum value of Snx, the relationship
2<Sx-max/Sx-min
holds, Snx varies on a random basis between Sx-min and Sx-max, the recess-protrusion structure is configured such that in an xz cross section, a recess portion and a protrusion portion are formed on each of adjacent intervals along the x-axis, respectively, and when dznx represents a difference between the maximum value and the minimum value of z coordinate of the recess-protrusion structure in the interval nx in the xz cross section, Anx represents a ratio between dznx and Snx, Anx-max represents the maximum value of Anx, and Anx-min represents the minimum value of Anx, the recess-protrusion structure is configured such that the relationship
Ax-max/Ax-min<1.3
holds.

### Claim 2 (depends on 1)

A diffuser according to claim 1, wherein when in the xz cross section, z coordinate of the recess-protrusion structure is represented as a function of x, the function of x on each interval can be approximated by a smooth function.

### Claim 3 (depends on 2)

A diffuser according to claim 2, wherein the function of x on each interval can be approximated by a quadratic function.

### Claim 4 (depends on 1)

A diffuser according to claim 1, wherein when a y-axis is defined on the plane so as to be orthogonal to the x-axis, the recess-protrusion structure is configured such that the shape of an xz cross section is identical independently of y coordinate.

### Claim 5 (depends on 1)

A diffuser according to claim 1, wherein when a y-axis is defined on the plane so as to be orthogonal to the x-axis, the y-axis is divided into plural intervals, my represents a positive integer for identifying an interval along the y-axis, Smy represents length in the y-axis direction of an interval my, Sy-max represents the maximum value of Smy, and Sy-min represents the minimum value of Smy, the relationship
2<Sy-max/Sy-min
holds, Smy varies on a random basis between Sy-min and Sy-max, the recess-protrusion structure is configured such that in a yz cross section, a recess portion and a protrusion portion are formed on each of adjacent intervals along the y-axis, respectively, and when dzmy represents a difference between the maximum value and the minimum value of z coordinate of the recess-protrusion structure in the interval my in the yz cross section, Amy represents a ratio between dznx and Smy, Ay-max represents the maximum value of Amy, and Ay-min represents the minimum value of Amy, the recess-protrusion structure is configured such that the relationship
Ay-max/Ay-min<1.3
holds.

### Claim 6

A method for manufacturing a diffuser provided with a recess-protrusion structure,
wherein when a z-axis is defined as a normal to a flat surface of a substrate, and an x-axis is defined on the flat surface, the method includes the steps of
dividing the x-axis into plural intervals such that the relationship
2<Sx′-max/Sx′-min
holds, and Snx′ varies on a random basis between Sx′-min and Sx′-max, where nx′ represents a positive integer for identifying an interval along the x-axis, Snx′ represents length in the x-axis direction of an interval nx′, Sx′-max represents the maximum value of Snx′, and Sx′-min represents the minimum value of Snx′;
forming a provisional recess-protrusion structure on the substrate by etching such that in an xz cross section, a recess portion and a protrusion portion are formed on each of adjacent intervals along the x-axis, respectively; and
forming a synthetic resin coating on the provisional recess-protrusion structure by spin coating such that the relationship
Ax-max/Ax-min<1.3
holds, where an interval nx represents an interval along the x-axis that corresponds to a recess portion or a protrusion portion of the recess-protrusion structure coated with the synthetic resin coating in the xz cross section, Snx represents length in the x-axis direction of the interval nx, dznx represents a difference between the maximum value and the minimum value of z coordinate of the recess-protrusion structure in the interval nx in the xz cross section, Anx represents a ratio between dznx and Snx, Anx-max represents the maximum value of Anx, and Anx-min represents the minimum value of Anx.

### Claim 7 (depends on 6)

A method for manufacturing a diffuser according to claim 6, wherein when a y-axis is defined on the flat surface so as to be orthogonal to the x-axis, in the step of forming the provisional recess-protrusion structure, the provisional recess-protrusion structure is formed such that the shape of an xz cross section is identical independently of y coordinate.

### Claim 8 (depends on 6)

A method for manufacturing a diffuser according to claim 6, wherein when a y-axis is defined on the flat surface so as to be orthogonal to the x-axis, the method further includes the step of
dividing the y-axis into plural intervals, before the step of forming the provisional recess-protrusion structure, such that the relationship
2<Sy′-max/Sy′-min
holds, and Smy′ varies on a random basis between Sy′-min and Sy′-max, where my′ represents a positive integer for identifying an interval along the y-axis, Smy′ represents length in the y-axis direction of an interval my′, Sy′-max represents the maximum value of Smy′, and Sy′-min represents the minimum value of Smy′,
in the step of forming the provisional recess-protrusion structure, the provisional recess-protrusion structure is formed on the substrate such that in a yz cross section, a recess portion and a protrusion portion are formed on each of adjacent intervals along the y-axis, respectively, and
in the step of forming the synthetic resin coating, the synthetic resin coating is formed such that the relationship
Ay-max/Ay-min<1.3
holds, where an interval my represents an interval along the y-axis that corresponds to a recess portion or a protrusion portion of the recess-protrusion structure coated with the synthetic resin coating in the yz cross section, Smy represents length in the y-axis direction of the interval my, dzmy represents a difference between the maximum value and the minimum value of z coordinate of the recess-protrusion structure in the interval my in the yz cross section, Amy represents a ratio between dznx and Smy, Ay-max represents the maximum value of Amy, and Ay-min represents the minimum value of Amy.