Light redirecting film

• US 10,649,225 B2
• Filed: 11/24/2017
• Issued: 05/12/2020
• Est. Priority Date: 07/20/2017
• Status: Active Grant

• Current Assignee: BENQ Materials Corporation
• Original Assignee: BENQ Materials Corporation
• Inventors: Kuo, Chen-Kuan, Hong, Cyun-Tai, Wu, Fung-Hsu
• Primary Examiner(s): Chang, Audrey Y
• Application Number:
  US15/821,893
• Publication Number:
  US 20190025480A1
• Time in Patent Office: 900 Days
• Field of Search: 359576, 359569, 359566, 348291, 348342, 349112, 349 62
• CPC Class Codes: G02B 1/04 made of organic materials, e.g. plastics G02B1/08 takes precedence
• CPC Class Codes: G02B 27/4211 correcting chromatic aberrations G02B27/0056, G02B27/4222, G02B27/4227 take precedence
• CPC Class Codes: G02B 27/4272 having plural diffractive elements positioned sequentially along the optical path
• CPC Class Codes: G02B 5/0252 using holographic or diffractive means
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/1823 in an overlapping or superposed manner
• CPC Class Codes: G02B 5/1842 Gratings for image generation G02B5/1847 takes precedence
• CPC Class Codes: G02B 5/1847 Manufacturing methods
• CPC Class Codes: G02B 5/1852 using mechanical means, e.g. ruling with diamond tool, moulding
• CPC Class Codes: G02B 5/1866 Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence

Abstract

A light redirecting film in a sandwich-laminated structure is provided. The light redirecting film comprises a first layer, a second layer; and an intermediate layer sandwiched between the first layer and the second layer. The intermediate layer includes a first grating surface having a plurality of first gratings extending in a first grating direction and a second grating surface opposite to the first grating surface having a plurality of second gratings extending in a second grating direction, wherein the first grating direction and the second grating direction cross each other at an angle of 90°±10°, and the first grating surface and the second grating surface of the intermediate layer are gap-filled and planarized with the first layer and the second layer respectively to generate the light redirecting film.

Claims

1. A light redirecting film in a sandwich-laminated structure, comprising:

a first layer having a first refraction index of n1;

a second layer having a third refraction index of n3; and

an intermediate layer having a second refraction index of n2, disposed between the first layer and the second layer, including a first grating surface having a plurality of first gratings extending in a first grating direction and a second grating surface opposite to the first grating surface having a plurality of second gratings extending in a second grating direction, wherein the first grating direction and the second grating direction cross each other at an angle of 90°

±

10°

;

wherein the first grating surface and the second grating surface of the intermediate layer are gap-filled and planarized with the first layer and the second layer respectively, and n2 is greater than n1 and n3, and when the light redirecting film is attached in front of the displaying side of a LCD, gamma values reflecting to the contrast ration and color saturation of the LCD are greater than 0.9 at different horizontal and/or vertical viewing angles ≤

80 degrees.

2. The light redirecting film according to claim 1, wherein the first refraction index of n1, the second refraction index of n2, and the third refraction index of n3 are all in the range of 1.4 to 1.7.

3. The light redirecting film according to claim 2, wherein n1 and n3 can be the same or different.

4. The light redirecting film according to claim 2, wherein the difference of n2 and n1 is no less than 0.1 and no more than 0.3.

5. The light redirecting film according to claim 2, wherein the difference of n2 and n3 is no less than 0.1 and no more than 0.3.

6. The light redirecting film according to claim 1, wherein each of the first gratings has a width of w1, each of the second gratings has a width of w2, and w1, w2 are independently in the range of 0.3 μ

m to 1.5 μ

m.

7. The light redirecting film according to claim 1, wherein each of the first gratings has a depth of d1, each of the second gratings has a depth of d2, and d1, d2 are independently in the range of 0.5 μ

m to 1.5 μ

m.

8. The light redirecting film according to claim 1, wherein the grating gap of g1 between adjacent two of the first gratings and the grating gap of g2 between adjacent two of the second gratings are independently in the range of 0.3 μ

m to 1.5 μ

m.

9. The light redirecting film according to claim 1, wherein the widths, the depths and the grating gaps of the first gratings and the second gratings can be the same or different.

10. The light redirecting film according to claim 1, further comprising an optical film adhered to the light redirecting film, wherein the optical film is selected from one of a group consisting of a polarizing film, a hard-coating film, a low reflective film, an anti-reflective film, an anti-glaring film and a protective film or combinations thereof.

11. A liquid crystal display (LCD) comprising:

a liquid crystal panel; and

a light redirecting film in a sandwich-laminated structure attached in front of the displaying side of the liquid crystal panel, comprising;

a first layer having a first refraction index of n1;

a second layer having a third refraction index of n3; and

an intermediate layer having a second refraction index of n2, disposed between the first layer and the second layer, including a first grating surface having a plurality of first gratings extending in a first grating direction and a second grating surface opposite to the first grating surface having a plurality of second gratings extending in a second grating direction, wherein the first grating direction and the second grating direction cross each other at an angle of 90°

±

10°

, and the first grating surface and the second grating surface of the intermediate layer are gap-filled and planarized with the first layer and the second layer respectively, and n2 is greater than n1 and n3;

wherein, gamma values reflecting to the contrast ration and color saturation of the liquid crystal display (LCD) are greater than 0.9 at different horizontal and/or vertical viewing angles ≤

80 degrees.

12. The liquid crystal display (LCD) according to claim 11, wherein the first refraction index of n1, the second refraction index of n2, and the third refraction index of n3 are all in the range of 1.4 to 1.7.

13. The liquid crystal display (LCD) according to claim 11, wherein the difference of n2 and n1 is no less than 0.1 and no more than 0.3.

14. The liquid crystal display (LCD) according to claim 11, wherein the difference of n2 and n3 is no less than 0.1 and no more than 0.3.

15. The liquid crystal display (LCD) according to claim 11, wherein each of the first gratings has a width of w1, each of the second gratings has a width of w2, and w1, w2 are independently in the range of 0.3 μ

m to 1.5 μ

m.

16. The liquid crystal display (LCD) according to claim 11, wherein each of the first gratings has a depth of d1, each of the second gratings has a depth of d2, and d1, d2 are independently in the range of 0.5 μ

m to 1.5 μ

m.

17. The liquid crystal display (LCD) according to claim 11, wherein the grating gap of g1 between adjacent two of the first gratings and the grating gap of g2 between adjacent two of the second gratings are independently in the range of 0.3 μ

m to 1.5 μ

m.

18. The liquid crystal display (LCD) according to claim 11, wherein the widths, the depths and the grating gaps of the first gratings and the second gratings can be the same or different.

19. The liquid crystal display (LCD) according to claim 11, further comprising an optical film adhered to the light redirecting film, wherein the optical film is selected from one of a group consisting of a polarizing film, a hard-coating film, a low reflective film, an anti-reflective film, an anti-glaring film and a protective film or combinations thereof.