Turning film having variable pitch

• US 20070019434A1
• Filed: 07/22/2005
• Published: 01/25/2007
• Est. Priority Date: 07/22/2005
• Status: Abandoned Application

• Current Assignee: SKC Haas Display Films Co., Ltd. (Dow, Inc.)
• Original Assignee: Eastman Kodak Company
• Inventors: Lee, Junwon
• Application Number:
  US11/188,153
• Publication Number:
  US 20070019434A1
• Time in Patent Office: Days
• US Class Current: 362/606
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer

Abstract

A light-redirecting article has a width and a length and has a light-redirecting surface with a plurality of light-redirecting structures elongated along the length of the light-redirecting article and arranged side-by-side. Each light-redirecting structure has a first side surface oriented away from a normal to the light-redirecting article at a first angle and a second side surface oriented away from a normal to the light-redirecting article at a second angle. The first and second side surfaces meet at an apex. The cross-sectional shape of each light-redirecting structure has at least one convex surface. For at least two adjacent light-redirecting structures, over the length of the at least two adjacent light-redirecting structures, the widthwise pitch between apexes of the adjacent light-redirecting structures varies by more than +/−3%.

Claims

1. A light-redirecting article having a width and a length, comprising:

a light-redirecting surface comprising a plurality of light-redirecting structures elongated along the length of the light-redirecting article and arranged side-by-side,

wherein each light-redirecting structure comprises;

(i) a first side surface oriented away from a normal to the light-redirecting article at a first angle;

(ii) a second side surface oriented away from a normal to the light-redirecting article at a second angle,

wherein the cross-sectional shape of each light-redirecting structure has at least one convex surface;

wherein the first and second side surfaces meet at an apex; and

wherein, for at least two adjacent light redirecting structures, over the length of the adjacent light redirecting structures the widthwise pitch between apexes of the adjacent light-redirecting structures varies by more than +/−

3%.

2. The light-redirecting article of claim 1 wherein the apex is a flat surface.

3. The light-redirecting article of claim 1 wherein the light-redirecting article comprises a layer integral with a film substrate.

4. The light-redirecting article of claim 1 wherein the light-redirecting structures are applied to a substrate layer.

5. The light-redirecting article of claim 1 wherein at least two adjacent light-redirecting structures have substantially the same height.

6. The light-redirecting article of claim 1 wherein all of the light-redirecting structures have substantially the same height.

7. The light-redirecting article of claim 1 wherein the widthwise pitch between the apexes of the adjacent light-redirecting structures increases and decreases in a random pattern over the length of the light-directing surface.

8. The light redirecting article of claim 7 wherein the pitch between the apexes of the adjacent light-redirecting structures increases and decreases by more than +/−

3% in a random pattern over the length of the element.

9. The light-redirecting article of claim 1 wherein at least two adjacent light-redirecting structures extend along a substantially sinusoidal path over the length of the light-directing surface.

10. The light-redirecting article of claim 1 wherein the first angle is between 1 and 25 degrees from normal.

11. The light-redirecting article of claim 1 wherein the convex curvature is spherical.

12. A method of manufacture of a light-redirecting article comprising:

a) rotating a cylinder;

b) scribing the rotating cylinder with a tool to form adjacent scribe marks having a pitch that, over one full rotation of the cylinder, varies by more than +/−

3%; and

c) forming the light-redirecting article using the scribed cylinder in an injection roll molding process.

13. The method of manufacturing of claim 12 wherein the resulting light redirecting article has a width and a length, comprising:

a light-redirecting surface comprising a plurality of light-redirecting structures elongated along the length of the light-redirecting article and arranged side-by-side,

wherein each light-redirecting structure comprises;

(i) a first side surface oriented away from a normal to the light-redirecting article at a first angle;

(ii) a second side surface oriented away from a normal to the light-redirecting article at a second angle,

wherein the cross-sectional shape of each light-redirecting structure has at least one convex surface ;

wherein the first and second side surfaces meet at an apex; and

wherein, for at least two adjacent light redirecting structures, over the length of the adjacent light redirecting structures the widthwise pitch between apexes of the adjacent light-redirecting structures varies by more than +/−

3%.

14. The method of manufacture according to claim 12 wherein scribing the rotating cylinder comprises tracing a substantially sinusoidal path with a scribing tool.

15. A display apparatus comprising

a) a light source;

b) a light guiding plate for directing light from the light source outward from an output surface, over a range of angles;

c) a light-redirecting article for accepting the light from the light guiding plate, the light redirecting article having a width and a length, comprising;

a light-redirecting surface comprising a plurality of light-redirecting structures elongated along the length of the light-redirecting article and arranged side-by-side,

wherein each light-redirecting structure comprises;

(i) a first side surface oriented away from a normal to the light-redirecting article at a first angle;

(ii) a second side surface oriented away from a normal to the light-redirecting article at a second angle,

wherein the cross-sectional shape of each light-redirecting structure has at least one convex surface;

wherein the first and second side surfaces meet at an apex; and

wherein, for at least two adjacent light redirecting structures, over the length of the adjacent light redirecting structures the widthwise pitch between apexes of the adjacent light-redirecting structures varies by more than +/−

3%.

the light-redirecting article providing illumination thereby; and

,

d) a light gating device for modulating the incident illumination from the light-redirecting article.

16. The display apparatus of claim 15 wherein the apexes of the light redirecting structures are a flat surface.

17. The display apparatus of claim 15 wherein the light-redirecting article is integral with a film substrate.

18. The display apparatus of claim 15 wherein the light-redirecting structures of the light redirecting article are applied to a substrate layer.

19. The display apparatus of claim 15 wherein the at least two adjacent light-redirecting structures of the light redirecting article have substantially the same height.

20. The display apparatus of claim 15 wherein all of the light-redirecting structures of the light redirecting article have substantially the same height.

21. The display apparatus of claim 15 wherein the widthwise pitch between the apexes of the adjacent light-redirecting structures increases and decreases in a random pattern over the length of the light-directing surface.

22. The display apparatus of claim 21 wherein the pitch between the apexes of the adjacent light-redirecting structures increases and decreases by more than +/−

3% in a random pattern over the length of the light-directing surface.

23. The display apparatus of claim 15 wherein the apex angles of the at least two adjacent light-redirecting structures of the light redirecting article extend along a substantially sinusoidal path along the length of the light-directing surface.

24. The display apparatus of claim 15 wherein the first angle of the light redirecting structure is between 1 and 25 degrees from normal.

25. The display apparatus of claim 15 wherein the convex curvature of the cross-sectional shape of each light-redirecting structure is spherical.