TW201028740A - Optical element, manufacturing method thereof, and a backlight module - Google Patents

Abstract

The invention provides an optical element, manufacturing method thereof, and a backlight module. The backlight includes said backlight module. The optical element includes pluralities of microstructures and pluralities of reflecting members. Each of the microstructures is extended along a first direction and arranged along a second direction on the emitting surface. The second curve is not parallel to the first curve. In the second direction, the distance between the first curve and the second curve is not equal to the distance between the other first curve and the second curve. Each of the reflecting members is extended along the first direction and arranged along the second direction on the incident surface. The position of each reflecting member is corresponding to the intersection of two microstructures. The thickness of the reflecting member is t, the width of the base of the microstructures is P, and the refractive index of the optical element is n. The t, P, and n satisfy the following equation: tan-1(P/10t) > sin-1(1/n) The optical element, satisfying the above equation, will achieves prefer optical effectiveness.

Description

201028740 VI. Description of the Invention: [Technical Field] The present invention relates to an optical element, and more particularly to an optical element having a micro structure and a reflective structure. [Prior Art] Fig. 1 is a partial cross-sectional view showing a brightness enhancement film of U.S. Patent No. 7,309,149. Referring to Fig. 1, a light-incident surface 12' of the brightness enhancement film includes a reflection structure 13'' when the first light L1, the second light L2, and the third light L3 are incident on the light-incident surface 12 of the brightness enhancement film. Thereafter, the first light ray L1 is refracted toward the front surface of the brightness enhancement film, the second light ray L2 is reflected from the reflection structure 13, and the third light ray L3 is reflected by the reflection structure 13, or the prism unit u. The reflected second light L2 and the third light L3 are again reflected by the reflecting plate (not shown) under the brightness enhancing film 200 to re-use the second light L2 and the third light L3. Due to the arrangement of the reflective structure 13', the light incident on the light incident surface is less likely to be refracted toward the side of the brightness enhancing film, so that when the user is viewed from the front side of the brightening group 1', it will feel higher. brightness. In US 7,309,149, its gauge reflective structure 13 has a width less than or equal to two-thirds of the distance between the prism elements 11'. However, it does not specify the spacing and thickness of the reflective structure 13', so that there is a general design in the art that cannot be further optimized according to US 7,309,149. Further, the above-mentioned prism units 11' are arranged in parallel with each other on the thin film 1'. Since the pixel electrodes on the liquid crystal panel are also arranged in parallel with each other, it is visually easy to generate the 4 201028740 ° month. Moire pattern.疋 It is worthwhile in this field. So how to solve the above problems. Usually the intellectuals think about it. SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical component that effectively eliminates the problem of a moiré pattern and also

: Specification with thickness to enable the general knowledge of the field = optimized design. According to the above and other objects, the present invention provides an optical device having a light emitting surface and a light incident surface, and light emitted by at least one light source placed in the light incident surface is generated inside the optical element. Eve optical path. The optical element includes a plurality of microstructures and a plurality of structures, wherein the microstructures extend along a first direction and are arranged on the light exit surface in a second direction. Each of the microstructures has a = edge. The top edge is located on the light exit surface and forms a plurality of first lines and a plurality of first curves adjacent to each other. The first curve and the second curve extend in a first direction. The distance between the first curve and the second curve in the second direction is unequal and non-parallel, and the second curve and the other first curve The distance between the second directions is not equal and not parallel. An additional 'each reflective structure extends along the first direction and is arranged on the light incident surface in accordance with the second direction, and the position of each reflective structure corresponds to the intersection of the two U$ type structures. The thickness t of the reflective structure, the width P of the bottom of the micro-structure, and the refractive index η of the optical element satisfy the following formula: 201028740 tan lOt >sin

Vn; wherein the optical path is incident on the light incident surface of the optical element by the thickness of the reflective structure to control the optical path, and the microstructures on the light exiting surface are used to converge the optical path. ~

In the above optical component, the profile of the longitudinal section of the microstructure is an arc 'the radius of curvature of the arc is R, and the distance between the first curve and the second curve in the second direction is d, r and D satisfy ^ The formula below: 0.5R < D < 3R. In the above optical element, the focal length FD of the microstructure and the width P of the bottom of the microstructure satisfy the following formula:

FD 0.25 <2.4<2.4 P 〇 In accordance with the above and other objects, the present invention provides a method of producing an optical element for manufacturing the above-described optical element, the method of manufacturing the optical element comprising the following steps. First, a transparent substrate is provided, and a molding gel is applied to the side of the transparent substrate. Further, a mold is provided having a plurality of molding patterns on the surface thereof, the shapes of the molding patterns corresponding to the microstructures on the optical elements. Thereafter, the mold is embossed on the molding gel, and the embossed molding compound is hardened to form a microstructure. Further, a photoresist layer is coated on the other side of the transparent substrate. Next, the photo-resist layer is subjected to an exposure and development process to form a junction-defective region, and the photoresist layer in the non-structural region is removed. Thereafter, a layer of reflective material is applied. Then, the photoresist layer of the structural region and the reflective material layer disposed thereon are removed, 6 201028740 and form a reflective structure. According to the above and other objects, the present invention provides a backlight module including an optical thin plate, at least one light source, and the optical component described above. The optical component is placed on the light emitting surface side of the optical thin plate. The optical sheet is a diffusion plate or a light guide plate. Φ In the above backlight module, the light source is a cold cathode fluorescent tube or a light emitting diode. The above described objects, features, and advantages of the present invention will become more apparent from the following description. [Embodiment] In the following embodiments, the second direction is represented by the X-axis direction, and the y-axis direction represents the first direction, but those skilled in the art should understand that this is only for convenience of representation, and Not limited to the first direction and the second direction. Referring to Figure 2, there is shown a perspective view of an optical component in accordance with a first embodiment of the present invention. The optical element 2 is substantially in the form of a thin plate, for example, disposed above the diffusing plate in the direct type backlight module, that is, the light emitting surface side of the diffusing plate. The light-emitting surface 21 of the optical element 2 has a plurality of microstructures 22 arranged on the light-emitting surface 21 along the X direction, and each of the microstructures 22 has a top edge 221 . Among them, the function of these micro structures 22 is to arrogate the optical path of the light 7 201028740 line ^

Further, a plurality of reflective structures 23 are disposed on the light incident surface 24 of the optical element 2. The reflective structures 23 are arranged on the light incident surface 24 along the X direction. The reflective structure 23 is made of titanium dioxide or magnesium oxide. Moreover, the position of each of the reflective structures 23 and the valleys 222 formed between the two micro-junctions 22 correspond to each other. Wherein, the thickness of the reflective structure "23 is t', the width of the bottom of the microstructure 22 is ρ, and the refractive index of the optical element 2 is η, and the following formula is satisfied: taniD>sini 丄) ........... ............Formula 1). As can be seen from Fig. 2, part of the light ray L4 is incident on the light incident surface 24, and part of the light ray L5 is reflected by the reflection structure 23, and the optical path of the light ray can be controlled by the thickness t of the reflection structure 23. Moreover, the microstructure 22 on the light exit surface 21 converges the optical path of the light ray L4. Referring to FIG. 2 and FIG. 3, FIG. 3 illustrates a plurality of curves formed by projection of the top edge on the pupil plane. As can be seen from Figure 2, the microstructure 22 extends substantially in the y-direction and the extended path of the microstructure 22 is curved. When the top edge 221 of the microstructure 22 is projected in the town, a variety of different curves are formed. Here, the curve from the left side to the odd position is called the first curve 221 = bit needs to be noted for convenience, and does not mean that The first curve 2212 has the same curved shape, and the first curve 2211 does not mean that all of the second curves 2212 8 201028740 have the same curved shape. Referring to FIG. 3, the first curve 2211 and the second curve 2212 are not parallel between the first curve 2211 and the second curve 2212. Wherein, each second curve 2212 is located between the two first curves 2211, and the distance between the first curve 2211 and the second curve 2212 on one side is D1, and the first curve 2211 on the other side is The distance between the second curves 2212 is D2. Wherein, the distance D1 and the distance D2 change along the y direction, and the distance D1 and the distance D2 are not the same. The profile of the longitudinal section of the microstructure 22 is an arc and the radius of curvature of the arc is R. Regardless of the distance D1 and the distance D2, collectively referred to herein as the distance D, the relationship with the radius of curvature R can be expressed as the following formula: 0.5R<D<3R................ ............Formula (2). In addition, the focal length of the microstructure is FD (not shown in the figure), and the following formula is satisfied:

FD 0.25 < — <2.4 P ...........................Formula (3). Since the pixel electrodes on the liquid crystal panel are also arranged in parallel with each other, and the extension path of the microstructure 22 of the present embodiment is curved, it is visually less likely to generate a moiré pattern. In addition, the applicant of the present invention performs computer simulation of the optical element 2 described above. In this simulation, the width P of the bottom of the microstructure 22 is set to 185 // m, and the refractive index η of the optical element 2 is 1.63. 201028740 Simulation state 1 --- 2 thickness t (private m) 43 --- 33 intensity 0.68 0.83 1/2 angle of view (·) 12.4 ------ J4.1

Wherein, the "intensity" of the above table represents the light intensity exhibited when viewed from the front of the optical element 2, and the "1/2 viewing angle" represents the viewing angle when the light intensity is reduced to 1/2 of the intensity of the front viewing light. Moreover, the simulation states 1 to 2 do not satisfy the formula (1), and the simulation states 3 to 5 satisfy the formula (1). Therefore, in summary, those skilled in the art can use the thickness of the reflection structure 23 The optical path of the light is controlled, and when the setting of the optical element 2 &)* satisfies the formula (1), it has a preferable optical effect. Hereinafter, a method of manufacturing the optical element 2 will be described. 4Α〜图4Ε. First, referring to FIG. 4A, a molding gel 22' is coated on one side of a transparent substrate 25, and the material of the transparent substrate 25 is, for example, polycarbonate or polynaphthalene. Polyethylene naphthalate (PEN) or polyethylene terephthalate (PET), the plastic 22' is, for example, an ultraviolet curing rubber or a thermoplastic resin. Further, a roller 4 is provided. 4 on the surface 41 a plurality of molding patterns (not shown) having a shape corresponding to the microstructure 22 of the optical element 2 (shown in FIG. 2). That is, the microstructure 22 has an upwardly convex shape and a molding pattern. Then, they are in the shape of a recessed downward 201028740, which complement each other. Then, referring to FIG. 4B, when the roller 4 is embossed on the molding compound 22, and the molding glue is hardened, a microstructure can be formed on the transparent substrate 25. 22. The curing method of the molding adhesive 22' varies depending on the type of the molding adhesive 22, for example, if the molding adhesive 22 is an ultraviolet curing adhesive, it is irradiated with ultraviolet rays to form it, and if the molding adhesive 22 is The thermoplastic resin is molded by heating. Further, in the present embodiment, the molding glue 22' is embossed using the roller 4, but those skilled in the art can replace the roller 4 with another type. Referring to FIG. 4C, after the fabrication of the microstructure 22 is completed, a photoresist layer is applied on the other side of the transparent substrate 25. Then, after the photoresist layer is applied, an exposure and development process is performed. To form The structural region 261 removes the photoresist layer other than the structural region 261 with a chemical agent, leaving only a portion of the structural region 261. Referring again to FIG. 4D, a reflective material layer 23 is applied, the reflective material layer 23, covering the structural region 26 and the photoresist layer of the structural region 261 will bond with the reflective material layer 23. Thereafter, please refer to FIG. 4E 'the photoresist layer of the structural region 261 and the reflective material layer 23 thereon 'Removal, the reflective structure 23 can be formed. After the fabrication of the reflective structure 23 is completed', the optical element 2 of the present invention is completed. Please refer to FIG. 5, which is shown in FIG. 5 as a direct type backlight using the optical element of the present invention. Module. The backlight module 5 includes a diffusing plate 51, a plurality of light sources 52, a reflecting cover 53 and the optical component 2 shown in FIG. 4, 201028740. In the embodiment, the light source 52 is a cold cathode fluorescent tube, but Change it to a light-emitting diode. The light source 52 is disposed in the reflective cover 53, and the reflective cover 53 reflects the light emitted from the light source 52 into the diffuser plate 51. The function of the diffusing plate 51 is to diffuse the light emitted by the light source 52. The main constituent material of the diffusing plate 51 is, for example, polymethyl methacrylate, polycarbonate or polyethylene terephthalate. Such as transparent substances. Further, a plurality of light-diffusing particles (not shown) are dispersed in the diffusion plate 51. The refractive index β of the light-diffusing particles is different from the main constituent material of the diffusion plate 51. Therefore, when the light passes through the light-diffusing particles, The optical path is deflected to achieve the effect of diffusing light. In FIG. 5, the backlight module 5 is a direct-type backlight module, but the optical component 2 of the present invention can also be used in other types of backlight modules, such as an edge-lit backlight module. In the edge-lit backlight module, the optical element 2 is disposed on the light guide plate. The present invention is described above by way of examples, and is not intended to limit the scope of the patent claims claimed herein. The scope of patent protection is subject to the scope of the patent application and its equivalent. Modifications or modifications made by those skilled in the art, without departing from the spirit or scope of the invention, are equivalent to the equivalents or modifications made in the spirit of the invention and should be included in the following claims. Inside. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partial cross-sectional view showing a brightness enhancement film of US7309M9t. 12 201028740

2 is a view showing an optical element according to a first embodiment of the present invention. Figure 3 depicts the projection of the top edge on the xy plane. 4A to 4E illustrate a method of manufacturing an optical element. FIG. 5 illustrates a backlight module according to a first embodiment of the present invention. [Main component symbol description] 1': Brightening film 11': prism unit 13': reflection structure L1: first light L2: second light L3: third light 2: optical element 21: light-emitting surface 22: microstructure 22 ' : molding adhesive 221 : top edge 222 : trough 2211 : first curve 2212 : second curve 23 : reflective structure 23 ′ : reflective material layer 24 : light incident surface 25 : transparent substrate 261 : structural region 4 · roller 41 : Surface 5: backlight module 51: diffuser 52: light source 53: reflector R: radius of curvature t: thickness P: width η: refractive index Dl, D2: distance L4, L5: light 13

Claims (1)

201028740 VII. Patent application scope: 1. An optical component having a light emitting surface and a light incident surface, and the light emitted by at least one light source placed on the light incident surface side generates at least one optical path inside the optical component. The optical component includes: a plurality of microstructures extending along a first direction and arranged along a second direction on the light exit surface, each of the microstructures having a top edge, the top edge being located on the light exit surface and adjacent to each other a plurality of first curves and a plurality of second curves, wherein the first curve and the second curve extend in the first direction, and the distance between the first curve and the second curve in the second direction is not equal Not parallel, and the distance between the second curve and the second curve in the second direction is not equal and non-parallel; a plurality of reflective structures each extending along the first direction and along the first Two directions are arranged on the light incident surface, and the position of each reflective structure corresponds to the intersection of the two microstructures, the thickness t of the reflective structure, the width P of the bottom of the microstructure, and the refraction of the optical element The rate η satisfies the following formula: >sin — ί Ρ ) tan——uotj wherein the optical path is incident from the light incident surface, and the optical path is controlled by the thickness of the plurality of reflective structures, and the light is emitted On the face These microstructures are used to converge the optical path. 2. The optical component of claim 1, wherein the profile of the longitudinal section of the microstructure is an arc, the radius of curvature R of the arc, and the first curve and the second curve are in the second direction The distance D above satisfies the following formula: 0.5R < D < 3R. The optical component of claim 1, wherein the focal length FD of the microstructure and the width P of the bottom of the microstructure satisfy the following formula: 0.25 < FD P < 2, 4 〇 4. A method of manufacturing an optical element for manufacturing an optical element according to claim 1, wherein the method of manufacturing the optical element comprises: Providing a transparent substrate, and applying a molding glue on one side of the transparent substrate; providing a mold having a plurality of molding patterns on the surface of the mold, and the appearance of the molding patterns and the optical element Corresponding to the micro-structure; embossing the mold on the molding glue, and hardening the embossed molding glue to form the micro-structure; applying a photoresist to the other side of the transparent substrate And performing an exposure and development process on the photoresist layer to form a structural region ′ and removing the photoresist layer of the non-structural region; coating a reflective material layer, the reflective material layer covering the structural region; The photoresist layer of the structural region is removed from the reflective material layer on the structural region to form the reflective structure. 5. The method of producing an optical component according to claim 4, wherein the material of the reflective material layer is titanium dioxide or magnesium oxide. 6. The method of producing an optical component according to claim 4, wherein the molding compound is an ultraviolet curing adhesive. The method of manufacturing an optical component according to claim 4, wherein the molding compound is a thermoplastic resin. 8. The optical component of claim 4, wherein the transparent substrate is made of polycarbonate, polyethylene naphthalate or polyethylene terephthalate. 9. A backlight module, comprising: an optical sheet; at least one light source disposed on a light incident side of the optical sheet; and, as described in any one of claims 1 to 3 An optical element placed on a light-emitting surface side of the optical sheet. 10. The backlight module of claim 9, wherein the optical sheet is a diffuser. 11. The backlight module of claim 9, wherein the optical sheet is a light guide. 12. The backlight module of claim 9, wherein the light source is a cold cathode fluorescent tube or a light emitting diode. 16