OPTICAL FILM

• US 20190025631A1
• Filed: 07/16/2018
• Published: 01/24/2019
• 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, Shen, Chuen-Nan, Lin, Meng-Jie, Lin, Chia-Feng, Cheng, Meng-Chia
• Granted Patent: US 10,642,086 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 27/4272 having plural diffractive elements positioned sequentially along the optical path
• CPC Class Codes: G02B 5/1842 Gratings for image generation G02B5/1847 takes precedence
• 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
• CPC Class Codes: G02B 5/223 containing organic substances, e.g. dyes, inks or pigments
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G11B 7/135 Means for guiding the beam from the source to the record carrier or from the record carrier to the detector

Abstract

The invention provides an optical film for improving image quality of a liquid crystal display comprising: a light directing structure layer, a first filling layer, a plurality of first diffraction gratings and a second filling layer. The light directing structure layer comprises a plurality of light directing micro structures, wherein the ratio of height to width of each light directing micro structure is in the range of 1.5 to 6. The first filling layer is disposed on the light directing structure layer, and the refractive index of the first filling layer and the light directing structure layer are different. The first diffraction gratings along with a first direction are formed on the first filling layer. The second filling layer is disposed on the first diffraction gratings and the refractive index of the second filling layer and the first diffraction gratings are different.

Claims

1. An optical film comprising:

a light directing structure layer comprising a plurality of light directing micro structures, wherein the ratios of height to width of the light directing micro structures are in the range of 1.5 to 6;

a first filling layer disposed on the light directing micro structures and covering the light directing micro structures, wherein the refractive index of the first filling layer and the light directing structure layer are different;

a plurality of first diffraction gratings along with first direction formed on the first filling layer; and

a second filling layer disposed on the first gratings, wherein the refractive index of the second filling layer and the first diffraction gratings are different.

2. The optical film according to claim 1, wherein the heights of the light directing micro structures are independently in the range of 15 μ

m to 30 μ

m.

3. The optical film according to claim 1, wherein the widths of the light directing micro structures are independently in the range of 5 μ

m to 9 μ

m.

4. The optical film according to claim 1, wherein the gaps between adjacent two of the light directing micro structures are independently in the range of 24 μ

m to 45 μ

m.

5. The optical film according to claim 1, wherein the light directing micro structures are continuous or discontinuous columnar micro structures.

6. The optical film according to claim 1, wherein the cross-sectional shape of each light directing micro structure is independently selected from one of the group consisting of polygon, circle, oval, quadrilateral and diamond shape.

7. The optical film according to claim 1, wherein the difference of the refractive index of the second filling layer and the first diffraction gratings is no less than 0.1 and no more than 0.3.

8. The optical film according to claim 1, wherein a plurality of second diffraction gratings along with second direction are formed on the second filling layer;

and the first direction and the second direction are substantially parallel.

9. The optical film according to claim 8, further comprising a third filling layer disposed on the second diffraction gratings for filling the second diffraction gratings, wherein the refractive index of the third filling layer and the second diffraction gratings are different.

10. The optical film according to claim 9, wherein the difference of the refractive index of the third filling layer and the second diffraction gratings is no less than 0.1 and no more than 0.3.

11. The optical film according to claim 8, wherein the widths of the first diffraction gratings and the widths of the second diffraction grating are independently in the range of 0.3 μ

m to 1.5 μ

m.

12. The optical film according to claim 8, wherein the gaps between adjacent two of the first diffraction gratings and the gaps between adjacent two of the second diffraction gratings are independently in the range of 0.3 μ

m to 1.5 μ

m.

13. The optical film according to claim 8, wherein the heights of the first diffraction gratings and the heights of the second diffraction gratings are independently in the range of 0.5 μ

m to 1.5 μ

m.

14. The optical film according to claim 1, wherein the light directing structure layer further comprising a dye including at least dye molecules or light-absorbing particles for absorbing light with a specific wavelength.

15. The optical film according to claim 1, wherein the first filling layer further comprising a dye including at least dye molecules or light-absorbing particles for absorbing light with a specific wavelength.

16. The optical film according to claim 1, wherein the second filling layer further comprising a dye including dye molecules or light-absorbing particles for absorbing light with a specific wavelength.

17. The optical film according to claim 9, wherein the third filling layer further comprising a dye including at least dye molecules or light-absorbing particles for absorbing light with a specific wavelength.

18. The optical film according to claim 1, further comprising an adhesive layer disposed between the first filling layer and the first diffraction gratings.

19. The optical film according to claim 9, further comprising a functional film adhered to the third filling layer, wherein the functional 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.