CN101819294B - An optical element, its manufacturing method and a backlight module - Google Patents

Abstract

The invention provides an optical element, a method for manufacturing the same and a backlight moduleAnd the backlight module comprises the optical element. The optical element comprises a plurality of micro-structures and a plurality of reflecting structures, wherein the micro-structures extend along a first direction and are arranged on the light-emitting surface along a second direction, the first curve and the second curve have unequal and nonparallel distances in the second direction, and the second curve and the other first curve have unequal and nonparallel distances in the second direction. Each reflection structure extends along the first direction and is arranged on the light incident surface along the second direction, the position of each reflection structure corresponds to the joint of two microstructures, the thickness t from each reflection structure to the light incident surface is provided, the length of each microstructure along the second direction is a width P, and the refractive index n of the optical element satisfies the following formula:

when the design of the optical element satisfies the above formula, it has better optical effect.

Description

A kind of optical element and its manufacturing approach and a backlight module

Technical field

The present invention relates to a kind of optical element and its manufacturing approach and a backlight module, relate in particular to a kind of optical element and its manufacturing approach and backlight module about having microstructure and reflection configuration.

Background technology

Fig. 1 illustrate is the part cut-open view of the brightness enhancement film among the US7309149.With reference to Fig. 1; Comprise a reflection configuration 13 ' on the incidence surface 12 ' of brightness enhancement film 1 '; After the first light L1, the second light L2 and the 3rd light L3 are incident in the incidence surface 12 ' of brightness enhancement film 1 '; First light L1 refraction towards the front of brightness enhancement film 1 ', the second light L2 is from reflecting structure 13 ' reflection, the 3rd light L3 then be reflected structure 13 ' or prism unit 11 ' reflection.Second light L2 that is reflected and the 3rd light L3 can be once again by the reflections of the reflecting plate (not shown) of brightness enhancement film 200 belows, so that utilize the second light L2 and the 3rd light L3 again.

Because the setting of reflection configuration 13 ' can make the light that is incident to incidence surface be difficult for the side refraction towards brightness enhancement film, therefore when the user was watched by the front of brightness enhancement film 1 ', it can experience higher brightness.

In US7309149, the width of its standard reflection configuration 13 ' be less than or equal to 11 of prism unit spacing 2/3rds.Yet it does not make standard to the interval of reflection configuration 13 ' with thickness, so those of ordinary skills can't make the design of further optimization according to US7309149.And; Described prism unit 11,11 ' all is arranged in brightness enhancement film 1 with parallel mode, on 1 '; Because the pixel electrode on the liquid crystal panel also is to arrange with parallel mode, therefore visually be easy to produce so-called folded line figure (moire pattern).

Therefore, how solving the above problems, is to be worth those of ordinary skills to go to consider ground.

Summary of the invention

The purpose of this invention is to provide a kind of optical element, this optical element can effectively be eliminated the problem of folded line figure, also standard is made with thickness in the interval of reflection configuration simultaneously, so that those of ordinary skills can make the design of optimization.

According to above-mentioned purpose and other purposes, the present invention provides a kind of optical element, and it has an exiting surface and an incidence surface, and the light that at least one light source sent that is positioned over the incidence surface side can produce at least one optical path in that optical element is inner.Optical element comprises a plurality of microstructures and a plurality of reflection configuration, and wherein microstructure is arranged on the exiting surface along first direction extension and along a second direction.Each microstructure has a top margin, and said top margin is positioned on the said exiting surface and forms multiple different curve at least, and the curve that number is positioned at odd positions from the left side is called first curve, and the curve that number is positioned at the even number position from the left side is called second curve.First curve and second curve extend toward first direction; Said first curve and said second curve distance between on the said second direction is unequal and not parallel, and between on the said second direction of said second curve and another first curve apart from unequal and not parallel.

In addition, each reflection configuration is arranged on the incidence surface along the first direction extension and according to second direction, and the position of each reflection configuration is corresponding each other with the junction of two microstructures.Each of said reflective structure to said light incident surface having a thickness t, while the second micro-structure along the line width is a length in the direction P, and the micro-structure of the refractive index of said optical element n, satisfies the following formula :

${\tan }^{-1}\left(\frac{P}{10t}\right)>{\sin }^{-1}\left(\frac{1}{n}\right).$

Wherein, optical path is the incidence surface incident by optical element, and the thickness through reflection configuration is with the control optical path, and the said microstructure on the exiting surface is in order to optical path is restrained.

In above-mentioned optical element, the profile of the longitudinal profile of microstructure is a camber line, and the radius-of-curvature of said camber line is R, and first curve and the distance of said second curve on said second direction are D, the formula below R and D satisfy: 0.5R＜D＜3R.

In above-mentioned optical element, the focal length FD of microstructure and described width P, the formula below satisfying:

$0.25<\frac{\mathrm{FD}}{P}<2.4.$

According to above-mentioned purpose and other purposes, the present invention provides a kind of manufacturing approach of optical element, is used to make above-mentioned optical element, and the manufacturing approach of this optical element comprises following step.At first, a transparent base is provided, and is coated with a moulding glue in a wherein side of said transparent base.Come, a mould is provided, have a plurality of moulding patterns on the surface of said mould, the external form of these moulding patterns is corresponding with the microstructure on the optical element.Afterwards, mould impresses on moulding glue, and the moulding glue behind the impression is hardened, to form microstructure.Come again, be coated with a photoresist layer in the other side of transparent base.Then, photoresist layer is carried out the exposure imaging processing procedure, forming a structural region, and the photoresist layer beyond this structural region removed.Afterwards, be coated with a last layer of reflective material, said layer of reflective material covers said structural region.Come again, the photoresist layer and the position layer of reflective material on it of structural region are removed, to form reflection configuration.

According to above-mentioned purpose and other purposes, the present invention provides a kind of backlight module, and this backlight module comprises an optical sheet, at least one light source and above-mentioned optical element, and optical element is positioned over the exiting surface side of optical sheet.

In above-mentioned backlight module, optical sheet is a diffuser plate or a LGP.

In above-mentioned backlight module, light source is cathode fluorescent tube or light emitting diode.

Compared with prior art, optical element of the present invention can effectively be eliminated the problem of folding the line figure, also standard is made with thickness in the interval of reflection configuration simultaneously, so that those of ordinary skills can make the design of optimization.

For letting above-mentioned purpose of the present invention, the feature and advantage more can be obviously understandable, hereinafter will and cooperate appended diagram with embodiment, elaborate as follows.

Description of drawings

Fig. 1 illustrate is the part cut-open view of the brightness enhancement film among the US7309149;

Fig. 2 illustrate is the optical element of the first embodiment of the present invention;

Fig. 3 illustrate is the projection of top margin on the xy plane;

Fig. 4 A～Fig. 4 E illustrate is the manufacturing approach of optical element;

Fig. 5 illustrate is the backlight module of the first embodiment of the present invention.

Description of reference numerals: 1,1 '-brightness enhancement film; 11,11 '-prism unit; 13 '-reflection configuration; L1-first light; L2-second light; L3-the 3rd light; The 2-optical element; The 21-exiting surface; The 22-microstructure; 22 '-moulding glue; The 221-top margin; The 222-trough; 2211-first curve; 2212-second curve; The 23-reflection configuration; 23 '-layer of reflective material; The 24-incidence surface; The 25-transparent base; The 261-structural region; The 4-roller; The 41-surface; The 5-backlight module; The 51-diffuser plate; The 52-light source; The 53-reflex housing; The R-radius-of-curvature; T-thickness; The P-width; The n-refractive index; D1, D2-distance; L4, L5-light.

Embodiment

In following embodiment, will represent second direction with the x direction of principal axis, the y direction of principal axis is represented first direction, understands this just convenience in order to represent but those of ordinary skills are said, but not the qualification that first direction and second direction are done.

Please with reference to Fig. 2, Fig. 2 illustrate is the stereographic map of the optical element of the first embodiment of the present invention.It is one lamellar that optical element 2 is substantially, and it for example is the top that is configured in the diffuser plate in the direct type backlight module, just the exiting surface side of diffuser plate.Wherein, the exiting surface 21 of optical element 2 has a plurality of microstructures 22, and these microstructures 22 are to be arranged on the exiting surface 21 along the x direction of principal axis, and each microstructure 22 has a top margin 221.Wherein, the function of these microstructures 22 is for the optical path of light is restrained.

In addition, on the incidence surface 24 of optical element 2, also being provided with a plurality of reflection configurations 23, these reflection configurations 23 are-are arranged on the incidence surface 24 along the x direction of principal axis, the material of reflection configuration 23 is titania or magnesium oxide.And the formed trough of 22 of the position of each reflection configuration 23 and two microstructures 222 is corresponding each other.Wherein, said each reflection configuration has a thickness t to said incidence surface, and the lengthwise length of two microstructures is a width P (the width P of each microstructure 22 bottom just), and the refractive index of optical element 2 is n, and the formula below satisfying:

${\mathrm{Tan}}^{-1}\left(\frac{P}{10t}\right)>{\mathrm{Sin}}^{-1}\left(\frac{1}{n}\right)$ ... ... ... ... .. formula (1).

Can be known that by Fig. 2 part light L4 is by incidence surface 24 incidents, the light L5 of part structure 23 reflection that then is reflected can be controlled the optical path of light through the thickness t of reflection configuration 23.And the microstructure 22 on exiting surface 21 can restrain the optical path of light L4.

Please with reference to Fig. 2 and Fig. 3, Fig. 3 illustrate is formed many curves of the projection of top margin on the xy plane.Can know that by Fig. 2 microstructure 22 is to extend toward the y direction basically, and the extension path of microstructure 22 is curved.When being projected on the xy plane up to I haven't seen you for ages, the top margin 221 of microstructure 22 forms multiple different curve; To be called first curve 2211 from the curve that left side number is positioned at odd positions at this, and will be called second curve 2212 from the curve that left side number is positioned at the even number position.Be noted that, curve is divided into the just convenience of explanation of first curve 2211 and second curve 2212, do not represent the first all curves 2211 all to have identical curve shape, also do not represent the second all curves 2212 all to have identical curve shape.

Please with reference to Fig. 3,2212 of first curve 2211 and second curve, 2212, the first curves 2211 and second curves are also not parallel.Wherein, each second curve 2212 is wherein between 2 first curves 2211, and the distance that is positioned at 2212 of first curve 2211 and second curves of a side wherein is D1, and the distance that is positioned at 2212 of first curve 2211 and second curves of an other side is D2.Wherein, distance B 1 can change along the y direction with distance B 2, and distance B 1 and distance B 2 and inequality.

The profile of the longitudinal profile of microstructure 22 is a camber line, and the radius-of-curvature of this camber line is R.No matter be distance B 1 and distance B 2, be referred to as distance B at this, can state following formula as with the relation of radius of curvature R:

0.5R＜D＜3R............................ formula (2).

In addition, the focal length of microstructure is FD (Focus Distance) (not being illustrated among the figure), and the formula below satisfying:

$0.25<\frac{\mathrm{FD}}{P}<2.4$ ... ... ... ... .... formula (3).

Because the pixel electrode on the liquid crystal panel also is to arrange with parallel mode, and the extension path of the microstructure 22 of present embodiment is curved, so it visually is difficult for producing folded line figure.

In addition, the applicant of this case carries out computer simulation with above-mentioned optical element 2, and in this simulation, the width P of the bottom of microstructure 22 is made as 185 μ m, and the refractive index n of optical element 2 is 1.63, is t through the thickness that changes reflection configuration 23, can obtain following table:

Emulation mode	1	2	3	4	5
						Thickness t (μ m)	43	33	20	13	4
Intensity	0.68	0.83	1.0	1.0	1.0
						1/2 visual angle (.)	12.4	14.1	16.5	17.8	19.4

Wherein, the light intensity that when the front of optical element 2 is watched, appeared of " intensity " of last table representative, 1/2 o'clock viewing angle of the light intensity that on behalf of light intensity, " 1/2 visual angle " then be kept to watch in the front.And emulation mode 1～2 does not satisfy formula (1), and 3～5 of emulation modes satisfy formula (1).

Therefore, in sum, those of ordinary skills can control the optical path of light through the thickness of reflection configuration 23, and when formula (1) was satisfied in the design of optical element 2, it had preferable optical effect.

Below, will introduce the manufacturing approach of above-mentioned optical element 2, please with reference to Fig. 4 A～Fig. 4 E.At first; Please with reference to Fig. 4 A; A moulding glue 22 ' in the coating of the wherein side of a transparent base 25, the material of this transparent base 25 for example be polycarbonate (polycarbonate), PEN (polyethylene naphthalate, PEN) or polyethylene terephthalate (polyethylene terephthalate; And moulding glue 22 ' for example is UV cured glue or thermmohardening glue PET).

Come, a roller 4 is provided, have a plurality of moulding patterns (not illustrating) on the surface 41 of said roller 4, the external form of these moulding patterns is corresponding with the microstructure 22 of optical element 2 (as shown in Figure 2).Just, microstructure 22 is shape protruding upward, and the moulding pattern then is the shape to lower recess, mends each other.

Afterwards, please with reference to Fig. 4 B, after roller 4 hardens at moulding glue 22 ' last impression and to moulding glue, just can on transparent base 25, form microstructure 22.The sclerosis mode of moulding glue 22 ' is difference along with the difference of the kind of moulding glue 22 '; For example if moulding glue 22 ' is UV cured glue; Then use ultraviolet ray to shine so that its moulding if moulding glue 22 ' is thermmohardening glue, then uses the mode of heating to make its moulding.In addition, in the present embodiment, use 4 pairs of moulding glue 22 ' of roller to impress, but those of ordinary skills can replace to roller 4 mould of other kenels.

Come again,, after the making of accomplishing microstructure 22, be coated with a photoresist layer at transparent base 25 opposite sides please with reference to Fig. 4 C.Then, behind the coating photoresist layer, carry out the exposure imaging processing procedure,, utilize chemical agent that the photoresist layer beyond the structural region 261 is removed, only stay the part of structural region 261 to form a structural region 261.

Come again,, be coated with a last layer of reflective material 23 ' please with reference to Fig. 4 D, said layer of reflective material 23 ' covered structure zone 261, and the photoresist layer of structural region 261 can produce the key knot with layer of reflective material 23 '.Afterwards,, the photoresist layer and the position layer of reflective material 23 ' on it of structural region 261 are removed, just can be formed reflection configuration 23 please with reference to Fig. 4 E.After accomplishing the making of reflection configuration 23, also just accomplished optical element 2 of the present invention.

See also Fig. 5, Fig. 5 illustrate is for using the direct type backlight module of optical element of the present invention.This backlight module 5 comprises a diffuser plate 51, a plurality of light source 52, a reflex housing 53 and optical element 2 shown in Figure 4, and wherein light source 52 is a cathode fluorescent tube in the present embodiment, but also can change it into light emitting diode.Light source 52 is to be configured in the reflex housing 53, and reflex housing 53 can reflex to the light that light source 52 is sent in the diffuser plate 51.The effect of diffuser plate 51 is that the light that light source 52 is sent is spread, and the main composition material of diffuser plate 51 for example is transparency materials such as polymethylmethacrylate (poly methyl methacrylate), polycarbonate or polyethylene terephthalate.And; In diffuser plate 51, then be scattered with a plurality of smooth diffusion particles (not illustrating), the main composition material of the refractive index of said smooth diffusion particle and diffuser plate 51 is also inequality, therefore when light passes through the light diffusion particle; Its optical path can produce deviation, thereby reaches the effect that makes the light diffusion.

In Fig. 5, backlight module 5 is a bottom-lighting type back light module, but optical element of the present invention 2 also can be used on the backlight module of other kenels, for example: side light type back light module.In side light type back light module, optical element 2 is to be configured on the LGP.

The above is merely preferred embodiment of the present invention, only is illustrative for the purpose of the present invention, and nonrestrictive.Those of ordinary skills understand, and in spirit that claim of the present invention limited and scope, can carry out many changes to it, revise, in addition equivalent, but all will fall in protection scope of the present invention.

Claims (10)

1. An optical element, characterized in that it has a light-emitting surface and a light-incident surface, and the light emitted by at least one light source placed on the side of the light-incidence surface will generate at least one optical element inside the optical element. The path, the optical element has a plurality of microstructures, the plurality of microstructures extend along a first direction and are arranged on the light-emitting surface along a second direction; each of the microstructures has a top edge , and the top edge is located on the light-emitting surface, and the x-axis direction represents the second direction, the y-axis direction represents the first direction, and the top edge is projected on the xy plane to form at least a variety of different curves; the curve at the odd position counting from the left is called the first curve, and the curve at the even position counting from the left is called the second curve, and the first curve and the second curve go toward the first curve. direction, the distance between the first curve and the second curve in the second direction is not equal and not parallel, and the distance between the second curve and another first curve in the second direction is not the same equal and not parallel; Wherein, the light-incident surface of the optical element is further provided with a plurality of reflective structures, each reflective structure extends along the first direction and is arranged on the light-incident surface along the second direction, And the position of each reflective structure corresponds to the intersection of two microstructures, each reflective structure has a thickness t to the light incident surface, and the width of the bottom of each microstructure is P, which is consistent with the The refractive index n of the optical element satisfies the following formula: ${\mathrm{<span\; class="notranslate">\; the\; tan</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; P</span>}}{\mathrm{<span\; class="notranslate">\; 10</span>}\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>{\mathrm{<span\; class="notranslate">\; sin</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; )</span>$ Wherein, the optical path is incident on the light-incident surface, and the optical path is controlled by the thickness of the plurality of reflective structures, and the plurality of microstructures on the light-emitting surface are used to convert the optical The path converges. 2. The optical element according to 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 The distance D of the curve in the second direction satisfies the following formula: 0.5R<D<3R. 3. The optical element according to claim 2, wherein the focal length FD and the width P of the microstructure satisfy the following formula: $\mathrm{<span\; class="notranslate">\; 0.25</span>}<span\; class="notranslate">\; <</span>\frac{\mathrm{<span\; class="notranslate">\; FD</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 2.4</span>}<span\; class="notranslate">\; .</span>$ 4. A method for manufacturing an optical element, used to manufacture the optical element as claimed in claim 1, wherein It is characterized in that the manufacturing method of the optical element comprises: providing a transparent substrate, and coating a molding glue on one side of the transparent substrate; providing a mold, the surface of the mold has a plurality of molding patterns, and the shapes of the plurality of molding patterns correspond to the microstructures on the optical element; embossing the mold on the molding glue, and hardening the embossed molding glue to form the microstructure; Coating a photoresist layer on the other side of the transparent substrate; Exposing and developing the photoresist layer to form a structure area, and removing the photoresist layer outside the structure area; applying a layer of reflective material covering the structured area; and The photoresist layer of the structure area and the reflective material layer on the structure area are removed to form the reflective structure. 5 . The method for manufacturing an optical element according to claim 4 , wherein the reflective material layer is made of titanium dioxide or magnesium oxide. 6 . The manufacturing method of the optical element according to claim 4 , wherein the molding glue is ultraviolet curing glue or thermosetting glue. 7 . 7. The method for manufacturing an optical element according to claim 4, wherein the material of the transparent substrate is polycarbonate, polyethylene naphthalate or polyethylene terephthalate. 8. A backlight module, characterized in that it comprises the optical element according to any one of claims 1 to 3, said backlight module comprising: an optical sheet; at least one light source placed on the light incident side of the optical sheet; and The optical element is placed on the light emitting surface side of the optical thin plate. 9. The backlight module according to claim 8, wherein the optical thin plate is a diffuser plate or a light guide plate. 10. The backlight module according to claim 8, wherein the light source is a cold cathode fluorescent lamp or a light emitting diode.

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