Optical film having multi-story and multi-peak prisms

Abstract

An optical film comprises: a transparent supporting layer, and a plurality of multi-story prisms having multiple peaks formed thereon and juxtapositionally integrally formed on the supporting layer, each peak of the prism tapered or narrowed upwardly towards a light output direction for increasing a light concentrating effect of the prism in order to increase the brightness of the optical film.

Description

BACKGROUND OF THE INVENTION

This application is an improvement of the prior application also filed by the same inventor of this application.

The prior application was filed on Mar. 3, 2006 given with an application Ser. No. 11/366,870, of which a typical drawing figure is attached herewith (as shown in FIG. 1) of this application.

The optical film of the prior application as shown in FIG. 1 includes a plurality of prisms 6 juxtapositionally formed on a supporting layer 5.

Each prism 6 of the prior application includes: a lower prism element 61 integrally formed with the supporting layer 5 and having two lower dihedral faces 6a, 6b disposed on opposite sides of the lower prism element 61 and cooperatively defining a first apex angle θ₁ between the two lower dihedral faces 6a, 6b; and an upper prism element 62 integrally superimposed on the lower prism element 61 and having two upper dihedral faces 7a, 7b disposed on opposite sides of the upper prism element 62 and cooperatively defining a second apex angle θ₂ between the two upper dihedral faces 7a, 7b; with the two lower dihedral faces 6a, 6b forming a first apex E₁, which is positioned below a second apex (E₂) as formed by the two upper dihedral faces 7a, 7b.

However, such a prior art has its first apex E₁ superimposed and “concealed” under the second apex E₂, thereby limiting a light concentrating effect of the prism 6, and influencing the luminance, brightness and luminous flux of an optical film thus formed.

The present inventor has made an improvement based upon the prior art by forming multi-peak and multi-story prisms on the supporting layer of the optical film.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an optical film comprising: a transparent supporting layer, and a plurality of multi-story prisms having multiple peaks formed thereon and juxtapositionally integrally formed on the supporting layer, each peak of the prism tapered or narrowed upwardly towards a light output direction for increasing a light concentrating effect of the prism in order to increase the brightness of the optical film.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an optical film of the prior art.

FIG. 2 shows a first preferred embodiment of the present invention.

FIG. 3 is a modification of the embodiment as shown in FIG. 2.

FIG. 4 shows another preferred embodiment of the present invention.

FIG. 5 shows another modification based on the embodiment as shown in FIG. 2.

FIG. 6 shows further preferred embodiment of the present invention.

FIG. 7 shows a modification based on the embodiment as shown in FIG. 6.

DETAILED DESCRIPTION

As shown in FIG. 2, the optical film of the present invention comprises: a transparent supporting layer 1, a basic prism 2 integrally formed on the supporting layer 1, and at least a parasitic prism 3 integrally formed on the basic prism 2.

The basic prism 2 is formed by two basic dihedral faces 21, 22 tapered upwardly towards a light output direction towards a viewer as generally indicated by numeral “L” as shown in FIG. 2 to define a first apex angle θ₁ between the two dihedral faces 21, 22, which may be 104° or any other proper degrees, having the two basic dihedral faces 21, 22 convergently intersected to form a first apex (or first peak) 23 on the top of the basic prism 2.

The parasitic prism 3 is formed by two parasitic dihedral faces 31, 32 tapered upwardly to define a second apex angle θ₂, which may be a right angle or an acute angle, having the two parasitic dihedral faces 31, 32 convergently intersected to form a second apex (or second peak) 33 on the top of the parasitic prism 3.

The second apex 33 is higher than the first apex 23 (H₂>H₁) so that the parasitic prism 3 may absorb the incidence light projecting into the parasitic prism 3 to reduce light loss of the optical film. Meanwhile, the prism 3 is tapered or narrowed upwardly to enhance its light concentrating effect. The basic prism 2 and the parasitic prism 3 have two peaks 23, 33 to thereby increase the brightness, luminance and luminous flux of the optical film, to be superior to the prior art.

The prisms 2, 3 may form two storys and there are two peaks (or two apexes). Accordingly, the present invention may be designated as an optical film having multi-story & multi-peak prisms.

The transparent supporting layer 1 may be made of thermoplastic resin including polyethylene terephthalate (PET), polycarbonate (PC), etc.

The prisms 2, 3 may be made of photo-sensitive or photo-curable resin or thermosetting resin including UV-curable resin, which are formed on the supporting layer 1 by molding or printing process.

As shown in FIG. 3, one face of the two dihedral faces 21, 22 has been formed as a curved surface 22a. The curvature radius may be made as large as possible.

Each of the dihedral faces of the prism may be formed as a flat or curved face, not limited in this invention.

The second apex 33 is formed on a left side of the first apex 23. However, the second apex 33 may also be positioned at the right side of the first apex 23.

The face 21 of the dihedral faces 21, 22 as shown in FIG. 2 may also be formed as a curved surface (not shown). Or, both dihedral faces 21, 22 may be formed as curved faces respectively.

As shown in FIG. 4, the optical film includes: a basic prism 2 integrally formed on the supporting layer 1 having a first apex 23 formed on a top of the basic prism 2 as convergently intersected by two basic dihedral faces 21, 22 tapered upwardly for defining a first apex angle θ₁; a first parasitic prism 3 integrally formed on the basic prism 2 having a second apex 33 formed on a top of the first parasitic prism 3 as convergently intersected by two parasitic dihedral faces 31, 32 tapered upwardly for defining a second apex angle θ₂; and a second parasitic prism 4 integrally formed on the basic prism 2 and juxtapositated opposite to the first parasitic prism 3, having a third apex 43 formed on a top of the second parasitic prism 4 as convergently intersected by two parasitic dihedral faces 41, 42 tapered upwardly for defining a third apex angle θ₃.

The third apex 43 may be higher than the second apex 33. Of course, the angle of each apex angle and the height of each apex is not limited in the present invention.

Preferably, at least one peak of the prisms should be the tallest among the peaks of the prisms in order to efficiently “catch” any incidence light projected inwardly from any external light sources or directions to prevent light loss of the optical film.

The first apex 23 of the basic prism 2 is “sandwiched” in between the two apexes 33, 43 of the two parasitic prisms 3, 4.

As shown in FIG. 4, the first apex 23 is coincidently located at the “valley” in between the two prisms 3, 4. However, the first apex 23 may also be protruded upwardly (not shown) to form triple peaks or apexes on a top portion of the basic prism 2 for increasing light concentrating effect of the optical film.

As shown in FIG. 5, the first apex 23 of the basic prism 2 as aforementioned has been modified to be a round peak or apex 23a, which becomes a preferred embodiment of the present invention.

As shown in FIG. 6, the parasitic prism 3 has its dihedral faces 31, 32 tapered upwardly respectively from the first apex 23 of the basic prism 2 and a right face 22 of the dihedral faces 21, 22 of the basic prism 2. The parasitic prism 3 is tapered upwardly to be narrower than the prism element (62) of the prior art as dotted line shown in FIG. 6 to increase its light concentrating effect of the optical film.

As shown in FIG. 7, the left face 21 of the dihedral faces 21, 22 of the basic prism 2 as shown in FIG. 6 has now been modified to be a curved face 21a and the right face 22 of the basic prism 2 has now been formed as a “base” of the parasitic prism 3 and been encompassed by the two dihedral faces 31, 32 of the parasitic prism 3. This is a further modification based on the embodiment as shown in FIG. 6.

The angles, shapes, heights, number of the prisms and peaks (or apexes) are not limited in the present invention. The number of storys of the prisms are also not limited.

The multiple or plural parasitic prisms may be juxtapositionally formed on the basic prism 2, or partially superimposed on the basic prism 2 to present multiple or plural peaks or apexes of the parasitic prisms formed on an upper or top portion of the basic prism 2 to increase the light concentrating effect of the optical film.

The present invention also comprises a method by forming, molding or printing the structured layer or layers including the multiple parasitic prisms and multiple peaks of the parasitic prisms on the basic prism.

The present invention may be modified without departing from the spirit and scope of the present invention.

Claims

1. An optical film comprising:

a transparent supporting layer;

a basic prism integrally formed on said supporting layer and having two basic dihedral faces of said basic prism tapered upwardly from said supporting layer to define a first apex angle between the two basic dihedral faces and to form a first apex or peak on a top of said basic prism as convergently intersected by the two basic dihedral faces; and

at least a parasitic prism integrally formed on said basic prism and having two parasitic dihedral faces of said parasitic prism tapered upwardly from one face of said two basic dihedral faces of said basic prism to define a second apex angle between said two parasitic dihedral faces and to form a second apex or peak on a top of said parasitic prism to be juxtapositioned to said first apex of said basic prism for forming multiple peaks above an upper or top portion of said basic prism for increasing a light concentrating effect.

2. An optical film according to claim 1, wherein each said peak of said prism is formed as a round peak.

3. An optical film according to claim 1, wherein each said face of said dihedral faces of the prism is selected from a flat face and a curved face.

4. An optical film according to claim 1, wherein said prisms include at least a peak which is the tallest among the multiple peaks of said prisms.

5. An optical film according to claim 1, wherein one said parasitic prism includes said two parasitic dihedral faces tapered upwardly respectively from said apex of said basic prism and from one face of said two basic dihedral faces of said basic prism.

6. An optical film according to claim 1, wherein said parasitic prism is tapered and narrowed upwardly towards a light output direction.

7. A process for making the optical film as set forth in claim 1 by integrally forming, molding or printing at least one said parasitic prism on said basic prism integrally formed on said supporting layer.