CN1510439A - Light guide plate and backlight module - Google Patents

Abstract

Translated fromChinese

本发明是关于一种导光板和采用该导光板的背光模组，该导光板包括一第一表面、一与该第一表面相对的第二表面、多个边侧面和多个扩散单元。其中，该第二表面是光出射面，该扩散单元设置于该第一表面，该多个边侧面中至少有一个为光入射面，而其它边侧面则为光反射侧面。各扩散单元在该第一表面的投影面积，和其与该多个边侧面内或外的至少一坐标点集合中各坐标点、和该各坐标点在该光反射侧面上形成的镜像坐标点的距离倒数平方和成正比。该扩散单元可以提高配合线光源的导光板和采用该导光板的背光模组的出光均匀度。

The invention relates to a light guide plate and a backlight module using the light guide plate. The light guide plate includes a first surface, a second surface opposite to the first surface, multiple sides and multiple diffusion units. Wherein, the second surface is a light emitting surface, the diffusing unit is disposed on the first surface, at least one of the plurality of sides is a light incident surface, and the other sides are light reflecting sides. The projected area of each diffusion unit on the first surface, and each coordinate point in the set of at least one coordinate point inside or outside the plurality of side surfaces, and the mirror image coordinate point formed by each coordinate point on the light-reflecting side surface The reciprocal sum of the squares of the distance is proportional to . The diffusion unit can improve the light uniformity of the light guide plate matched with the line light source and the backlight module adopting the light guide plate.

Description

Light guide plate and module backlight

[technical field]

The present invention relates to the module backlight of a kind of light guide plate and this light guide plate of employing.

[background technology]

Because the liquid crystal itself in the panel of LCD is not had a characteristics of luminescence, so,, need to give the LCD panel that one planar light source device is provided for reaching display effect, as module backlight, its function is area source abundant to panel of LCD supply briliancy and that be evenly distributed.

Prior art module backlight mainly is made up of light source, light guide plate, reflecting plate, diffuser plate and prism plate.Wherein, this light source can be arranged at light guide plate one side or two opposite sides and with light emission to this light guide plate.The effect of this light guide plate is the transmission direction of direct light line, makes light by the even outgoing of the exiting surface of light guide plate.Because the light that light source sends is to enter from the light guide plate side, so light guide plate is brighter near the part of light source, and darker away from the part of light source, therefore, for increasing the light extraction efficiency and the uniformity coefficient of light guide plate, the one side in light guide plate is provided with V-shaped groove or configuration light diffusion site usually.When light transmission during to V-shaped groove or light diffusion site, reflection and scattering will take place in light, and to each different directions transmission, finally by the exiting surface ejaculation of light guide plate.Utilize various densitys, the V-shaped groove that varies in size or light diffusion site, can make light guide plate luminous evenly.

A kind of prior art module backlight with bottom surface network point distribution as depicted in figs. 1 and 2, it is exposed in No. the 5th, 363,294, the United States Patent (USP) of bulletin on November 8th, 1994.The module backlight that this patent discloses comprises alight guide plate 22, aline source 21, adiffuser plate 27 and two reflectingplates 25,29.Thislight guide plate 22 comprises alight entrance face 223, light-emittingface 221,end face 224 andbottom surface 222, thisline source 21 is positioned at thislight guide plate 22light entrance faces 223 1 sides, this reflectingplate 29 is arranged at thisend face 224 1 sides, thesediffuser plate 27 relative these light-emittingfaces 221 are provided with, and these reflectingplate 25 relative thesebottom surfaces 222 are provided with.Wherein, onereflection lampshade 28 is set around thisline source 21 for the light that effectively utilizesline source 21 to be sent.Theselight guide plate 22 bottom surfaces are provided withmany sites 26 that the ranks shape is arranged that are.

Seeing also Fig. 2, is the distribution schematic diagram of thissite 26 in theselight guide plate 22 bottom surfaces 222.The direction of these 26 edges, site andline source 21 axially parallels is lined up multiple row, andsite 26 big or small identical in each row.Multirow is lined up withline source 21 axial vertical directions in these 26 edges, site, and the varying in size ofsite 26 in each row, wherein, nearsite 26 minimums ofline source 21, along with andline source 21 between the increase of distance, thissite 26 is linear to become big gradually.Owing to the increase along with transmission range of the intensity ofline source 21 emitted lights reduces, andlight guide plate 22 is posted reflecting plate 29 (as shown in Figure 1) away from an end face ofline source 21,29 pairs of reflections that are incident upon its glazed thread of this reflecting plate, causing theselight guide plate 22 interior light intensities is not to reach minimum at theend face 224 away fromline source 21, and its minimum light line strength present position is betweenlight entrance face 223 andend face 224 and near this end face 224.The minimum place of the size of thissite 26 light intensity in thislight guide plate 22 reaches maximum, and thereupon with constant size distribution to theend face 224 of thislight guide plate 22 away fromline source 21.

Thislight guide plate 22 can solve near the part ofline source 21 luminous brighter substantially, and away from the luminous darker technical matters ofline source 21 parts, but, because theselight guide plate 22end faces 224 are provided with reflectingplate 29, it is with in the light reflected backlight guide plate 22 of incident on it, causing near theselight guide plate 22 end faces 224 actual light line strengths is not to be constant size distribution, but the mostclose end face 224 place's light intensities are than the part away fromend face 224 is big slightly, this is called the edge reflection effect, so near the constant size distribution of thissite 26end face 224 can not make theselight guide plate 22 bright dippings even.Equally, also there is the edge reflection effect problem in light guide plate near 22 sides 225, and row can not make theselight guide plate 22 bright dippings even to the constant size distribution of thesite 26 of arranging.

In addition, because the light that sends ofline source 21 is inlight guide plate 22 in the transmission course, usually repeatedly reflection betweenlight guide plate 22 light-emittingfaces 221 andbottom surface 222, itslight guide plate 22 fromlight source 21 to end face near 224 partly actual light line strength be not to be the linear relationship variation.Becauseline source 21 has certain-length, the light thatlight guide plate 22 is accepted near the part atline source 21 centers is more than the part nearline source 21 two ends, and, low in the middle of the brightness ratio ofline source 21 two ends near the electrode part, causelight guide plate 22 lower than the luminosity ofclose line source 21 cores near the luminosity ofline source 21 two end portions, therefore, the distribution of thissite 26 in theselight guide plate 22 bottom surfaces still is difficult to realize the complete uniformity of wholelight guide plate 22 luminous exitances.

In addition, whenline source 21 replaces to pointolite such as a plurality of light emitting diode (LightEmitting Diode) (scheming not show), because these a plurality of light emitting diodes form a line, the part near these a plurality of light emitting diode ranks two ends is many for the light thatlight guide plate 22 is accepted near the part at this a plurality of light emitting diode ranks center, causelight guide plate 22 lower than part luminosity near this a plurality of light emitting diode ranks center near near part (the side 225) luminosity of these a plurality of light emitting diode ranks two ends, andlight guide plate 22 is close to each light emitting diode luminosity partly than the part height between each light emitting diode, thereby influences the optical property of this light guide plate.

Equally, adopt the luminous uniformity coefficient of module backlight of light guide plate of above-mentioned points of engagement light source also lower.

[summary of the invention]

The defective of non-uniform light the invention provides a kind of light guide plate and module backlight that adopts pointolite to have higher luminous uniformity coefficient when adopting pointolite as light source in order to overcome prior art light guide plate and module backlight.

The technical scheme that technical solution problem of the present invention is adopted is: a light guide plate is provided, and this light guide plate comprises a first surface, one and this first surface opposing second surface, a plurality of flank side surface and a plurality of diffusion unit.Wherein, this second surface is a light-emitting face, and this diffusion unit is arranged on this first surface, and these a plurality of flank side surface have at least one to be light entrance face, and other flank side surface then is the light mirrored sides.The inverse distance quadratic sum of each diffusion unit mirror image coordinate points that each coordinate points and this each coordinate points form on this light mirrored sides in the projected area of this first surface and itself and these a plurality of flank side surface or in outer at least one coordinate points set is directly proportional.

The present invention provides a kind of module backlight simultaneously, and this module backlight comprises an at least one pointolite and an above-mentioned light guide plate.

Compare with prior art, the present invention has the following advantages: it is proportional that intensity is derived at the light of the projected area of this bottom surface and light-emitting face corresponding region in the site of bottom surface of light guide plate of the present invention, can make the light guide plate of pointolites such as this cooperations light emitting diode and adopt the module backlight of this light guide plate luminous even.

[description of drawings]

Fig. 1 is the side view of prior art module backlight.

Fig. 2 is the network point distribution synoptic diagram of bottom surface of light guide plate shown in Figure 1.

Fig. 3 is the side view of light guide plate first embodiment of the present invention.

Fig. 4 is the network point distribution synoptic diagram of bottom surface of light guide plate shown in Figure 3.

Fig. 5 is coordinate points set shown in Figure 4 and its mirror image coordinate points set synoptic diagram in this light guide plate light mirrored sides.

Fig. 6 is the synoptic diagram that adopts the module backlight of light guide plate first embodiment of the present invention.

Fig. 7 is the side view of light guide plate second embodiment of the present invention.

Fig. 8 is the synoptic diagram of the network point distribution of bottom surface of light guide plate shown in Figure 7.

Fig. 9 is the side view of light guide plate the 3rd embodiment of the present invention.

[embodiment]

Please consulting Fig. 3 and Fig. 4 together, is the side view of light guide plate first embodiment of the present invention and the network point distribution synoptic diagram of bottom surface.Thislight guide plate 32 comprises alight entrance face 323, a light-emittingface 321, a plurality oflight reflection surface 324, abottom surface 322 and a plurality oflight diffusion site 36 that is distributed in bottom surface 322.Wherein, thislight guide plate 32 is rectangular flats, and this light-emittingface 321 andbottom surface 322 are to be oppositely arranged.

Thislight guide plate 32 is to make with transparent material such as acryl resin, polycarbonate, polyvinyl resin or glass etc.Thislight entrance face 323 receives from the light source light of (figure does not show), and it is imported in this light guide plate 32.This light-emittingface 321 is derived thislight guide plate 32 with light.Thislight reflection surface 324 will be incident upon light reflected backlight guide plate 32 on it from by these light-emittingface 321 outgoing, cause damage from theselight reflection surface 324 outgoing to prevent light.Light reflection surface 324 andbottom surface 322 can attach reflecting plate, also can adopt reflectance coating directly to plate thereon, so that the light of transmission fully reflects inlight guide plate 32, finally from light-emittingface 321 outgoing.

Thissite 36 is arranged on theselight guide plate 32bottom surfaces 322, and it is outstanding outside bottom surface 322.Thissite 36 is the outgoing light homogeneity that are used for improving thislight guide plate 32, and it is other light diffusion unit also, as prism structure etc.Thissite 36 can make by the method for printing or ejection formation.Thissite 36 is circle spherical surface body, and its projection inlight guide plate 32bottom surfaces 322 is circular, and certainly, thissite 36 also can be ellipsoid, polyhedron, cone or the most advanced and sophisticated taper platform etc. of pruning, its in thebottom surface 322 projection also corresponding can be ellipse or polygon.Thissite 36 presents the ranks distribution of shapes on thebottom surface 322 of thislight guide plate 32, wherein, the edge is provided withmultiple row site 36 withlight entrance face 323 parallel directions (being denoted as Y among the figure) with proportional spacing, and the edge is provided withmultirow site 36 withlight entrance face 323 vertical directions (being denoted as X among the figure) with proportional spacing.For further strengthening the effect of the 36 pairs of light in site, also can stagger the hemistich distance respectively and present the alternating expression distribution withlight entrance face 323 parallel and adjacent odd column and evencolumn sites 36, certainly, thissite 36 also can be otherwise regularly arranged.

Seeing also Fig. 5, is coordinate points set 37 shown in Figure 4 and its mirror image coordinate points set 37 ' synoptic diagram in theselight guide plate 32 smooth mirrored sides 324.Because this light mirroredsides 324 is minute surfaces, so this coordinate points set 37 is a minute surface and form three mirror image coordinate points and gather 37 ' in thatlight guide plate 32 is outside with three light mirrored sides 324.Each coordinate points is relevant in the projected area ofsite 36 on thisbottom surface 322 and thislight entrance face 323 or in outer at least one coordinate points set 37, also relevant with the mirror image coordinate points 37 ' that on this light mirroredsides 324, forms of each coordinate points in theset 37 of this coordinate points, its physical relationship is: thissite 36 on thisbottom surface 322 projected area and its with these a plurality of smooth mirroredsides 324 in or each coordinate points in outer at least one coordinate points set 37, and the inverse distance quadratic sum of the mirror image coordinate points 37 ' that on this light mirroredsides 324, forms of this each coordinate points be directly proportional.The radius size R of eachsite 36 satisfies formula:

$R=r_0+k\sqrt{\underset{h=1}{\overset{w-m}{\mathrm{\Σ}}}\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\underset{i=1}{\overset{n_i}{\mathrm{\Σ}}}{f}_h\frac{1}{{(X-X_{\mathrm{hji}})}^2+{(Y-Y_{\mathrm{hji}})}^2}+\underset{j=1}{\overset{m}{\mathrm{\Σ}}}\underset{i=1}{\overset{n_j}{\mathrm{\Σ}}}\frac{1}{{(X-X_{\mathrm{ji}})}^2+{(Y-Y_{\mathrm{ji}})}^2}}$

Wherein, (X, Y), (X_Ji, Y_Ji) and (X_Hji, Y_Hji) belong to a rectangular coordinate system, (X Y) is the coordinate ofsite 36, (X_Ii, Y_Ii) be the coordinate of each coordinate points in theset 37 of respective coordinates point, (X_Hji, Y_Hji) be the coordinate of each coordinate points each coordinate points in the mirror image coordinate points 37 ' of this light mirroredsides 324 in theset 37 of respective coordinates point, w is the summation oflight guide plate 32 wholelight entrance faces 323 and light mirroredsides 324 numbers, m is the number oflight entrance face 323, then the number of light mirroredsides 324 is: w-m, suppose that eachlight entrance face 323 only has coordinate points set 37, n_jBe the number of coordinate points in the correspondinglight entrance face 323 1 side coordinate points set 37, for present embodiment, m is 1, and w is 4, so the number of light mirroredsides 324 is 3, and n_jPromptly be n₁, numerical value is 3, f_hBe the reflectivity of corresponding light mirroredsides 324, i and j are natural number, and h is an integer, r₀With k be constant, corresponding to the light guide plate of different structure and size, different coordinate points set 37 has different k value and r with wherein coordinate points quantity with the position₀Value.

Whenlight guide plate 32 of the present invention is used for module backlight, assite 36 not being set in itsbottom surface 322, in it light derive intensity fromlight entrance face 323 to the light mirrored sides near 324 partly (C districts) far away more weak more fromlight entrance face 323,light guide plate 32 betweenlight entrance face 323 and the mirroredsides 324 partly (B district) luminous relative C districts a little less than, but, owing to have the edge reflection effect near thelight guide plate 32 smooth mirroredsides 324, the actual light line strength in (A district) is bigger away from this light mirroredsides 324 places (B district) intensity than slightly near theselight guide plate 32 smooth mirroredsides 324, like this, when thebottom surface 322 in thislight guide plate 32 is provided with thesite 36 that distributes according to the present invention, sincesite 36 on thisbottom surface 322 projected area and the light of light-emittingface 321 corresponding regions to derive intensity proportional, thereby can realize the whole evenly bright dipping of thislight guide plate 32.

Please refer to Fig. 6, is the synoptic diagram that adopts module backlight one embodiment of light guide plate of the present invention.This module backlight compriseslight guide plate 32 and is arranged on the light source 31 of its side that as a plurality of light emitting diodes, theselight guide plate 32bottom surfaces 322 are provided with reflecting plate or reflectance coating (figure does not show).Light penetrates from light source 31, enter a part of light inlight guide plate 32 backs and on thesite 36 ofbottom surface 322, carry out scattering and reflection, in the reflecting plate or reflectance coating reflected backlight guide plate 32 that the light that is incident uponbottom surface 322 is provided with by thisbottom surface 322, thereby can realize the whole uniformly light-emitting of this module backlight.

Second embodiment of light guide plate of the present invention as shown in Figure 7 and Figure 8.This light guide plate 42 comprises the site 46 on two light entrance faces 423, a light-emitting face 421, light reflection surface 424, a bottom surface 422 and the bottom surface 422.Wherein, this light guide plate 42 is rectangular flats, and this light-emitting face 421 and bottom surface 422 are to be oppositely arranged.This embodiment and first embodiment are basic identical, and difference is that the light entrance face 423 of second embodiment is two, and certainly, light entrance face 423 also can be more than two.Coordinate points set 47 is all arranged near this two light entrance face 423, its number adds up to 6, certainly, also can be other numerical value, and arrange in the projected area of this bottom surface 422 and depend on that this coordinate points gathers the distance of 47 numbers and the set 47 of each coordinate points and this site 46 in this site 46.

When present embodiment light guide plate 42 is used for module backlight, if site 46 is not set in its bottom surface 422, then in it light to derive intensity partly far away more weak more from light entrance face 423 near 424 from light entrance face 423 to the light mirrored sides, the light guide plate 42 between light entrance face 423 and the light mirrored sides 424 partly luminous relatively a little less than.But, owing to have the edge reflection effect near the light guide plate 42 smooth mirrored sides 424, near these light guide plate 42 smooth mirrored sides 424 actual light line strength is big away from these light mirrored sides 424 place's intensity more slightly, and when the site 46 that distributes according to the present invention is set in these light guide plate 42 bottom surfaces 422, because it is proportional that intensity is derived at the light of the projected area of this bottom surface 422 and light-emitting face 421 corresponding regions in site 46, thereby can realize this light guide plate 42 whole uniformly light-emittings.

Seeing also Fig. 9, is the side view of light guide plate the 3rd embodiment of the present invention.Thislight guide plate 52 comprises the site 56 on alight entrance face 523, a light-emittingface 521,light reflection surface 524, abottom surface 522 and the bottom surface 522.Wherein, thislight guide plate 52 is clapboards, and this light-emittingface 521 andbottom surface 522 are to be oppositely arranged, and the projected area of this site 56 on thisbottom surface 522 distributes similar with first embodiment of the invention.

Certainly, light guide plate of the present invention can also be other shape, as arc, bending plate etc.; This site also can be arranged at the light-emitting face of light guide plate of the present invention; This site also can recessed this bottom surface; This coordinate points set also can be arranged in the light entrance face of this light guide plate.

When above-mentioned light guide plate is used for module backlight, in the light guide plate flank side surface or outer coordinate points set place can the set-point light source, as light emitting diode.

Claims (9)

1. light guide plate, it comprises a first surface, one with this first surface opposing second surface, a plurality of flank side surface and a plurality of diffusion unit, this second surface is a light-emitting face, these a plurality of flank side surface have at least one to be light entrance face, other flank side surface is the light mirrored sides, this diffusion unit is arranged at this first surface, it is characterized in that: each diffusion unit in the projected area of this light guide plate first surface and itself and this a plurality of flank side surface or outer at least one coordinate points gather in each coordinate points, the inverse distance quadratic sum that is integrated into each coordinate points in the mirror image coordinate points set that forms on this light mirrored sides with this each coordinate points is directly proportional.

2. light guide plate as claimed in claim 1 is characterized in that: the diffusion unit on this light guide plate first surface protrudes or recessed this bottom surface.

3. light guide plate as claimed in claim 1 is characterized in that: this diffusion unit is circular in the projection of this light guide plate first surface.

4. light guide plate as claimed in claim 1 is characterized in that: this diffusion unit is ellipse or polygon in the projection of this light guide plate first surface.

5. light guide plate as claimed in claim 1 is characterized in that: this diffusion unit shape is roughly the same.

6. light guide plate as claimed in claim 1 is characterized in that: this diffusion unit is an arranged.

7. light guide plate as claimed in claim 1 is characterized in that: this first surface and this diffusion unit are one-body molded.

8. light guide plate as claimed in claim 3 is characterized in that: this diffusion unit at the circular radius R of the projection of this first surface is:

$R=r_0+k\sqrt{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\∫}_0^{L_i}\frac{1}{{(X-(l_i\cos {\mathrm{\θ}}_i+{\mathrm{xs}}_i))}^2+{(Y-(l_i\sin {\mathrm{\θ}}_i+{\mathrm{ys}}_i))}^2}}{\mathrm{dl}}_i$

Wherein, (X, Y), (X_Ji, Y_Ji) and (X_Hji, X_Hji) belong to a rectangular coordinate system, (X Y) is the coordinate of each diffusion unit, (X_Ji, Y_Ji) be the coordinate of each coordinate points in the set of respective coordinates point, (X_Hji, Y_Hji) be the coordinate of each coordinate points each coordinate points in the mirror image coordinate points of this light mirrored sides in the set of respective coordinates point, w is the summation of whole light entrance faces of light guide plate and light mirrored sides number, m is the number of light entrance face, w-m is the number of light mirrored sides, suppose that each light entrance face only has coordinate points set, n_jBe the number of coordinate points in the corresponding light entrance face one side coordinate points set, f_hBe the reflectivity of corresponding light mirrored sides, I and j are natural number, and h is an integer, r₀With k be constant, with the position different k value and r are arranged with wherein coordinate points quantity corresponding to the light guide plate of different structure and size, different coordinate points set₀Value.

9. a module backlight comprises an at least one pointolite and a light guide plate, and this pointolite is arranged on this light guide plate light entrance face one side, it is characterized in that: this light guide plate is as each described light guide plate of claim 1 to 9.

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