CN102455458B - Light guide device and backlight module - Google Patents

Abstract

The present invention discloses a light guide device and a backlight module. The light guide device includes a body and a plurality of microstructure parts. The body has a refractive index n and includes a light emitting surface, a base surface and at least one light incident surface. The base surface is separated from the light emitting surface by a thickness T. The microstructure parts are located on the base surface. Each microstructure part has a width P and includes a first distance _L1 and a second distance _L2 . The spacing between two microstructure parts is S. The light guide device satisfies the following relationship:

Therefore, the light guide device and the backlight module used therein have optimal optical uniformity.

Description

Light guide device and backlight module

technical field

The invention relates to a light guide device and a backlight module using the light guide device, in particular to a light guide device with both light guide and light diffusion effects and a backlight module used therein.

Background technique

In recent years, traditional cathode ray tube displays (commonly known as CRT displays) have been gradually replaced by liquid crystal displays. The main reason is that the amount of radiation emitted by liquid crystal displays is far less than that of CRT displays. The manufacturing cost of LCDs has decreased significantly, which is why LCD monitors are gradually becoming the mainstream of the TV or computer screen market.

Generally speaking, a liquid crystal display includes a liquid crystal panel and a backlight module; in a small-sized liquid crystal display, in order to avoid excessive thickness or high cost of the liquid crystal display, a side-type backlight module is usually used. Usually, the side-type backlight module will include a light guide device and at least one light source. , the light is transmitted inside the light guide device, and then emitted from one side of the light guide device. Among them, the most important function of the light guide device is to guide light through the arrangement of microstructures or partial reflection of reflective dots, so that the light is evenly emitted from the surface of the light guide device.

However, due to structural constraints, the light emitted by the light guide device usually exhibits a "dark band phenomenon" with alternating light and dark, which makes the uniformity of the entire backlight module poor and affects the user's visual perception.

Contents of the invention

The purpose of the embodiment of the present invention is to provide a light guide device for the defects of the above-mentioned prior art, so that the light emitted by the light guide device has better uniformity, eliminate the "dark band phenomenon" of the backlight module, and further improve the liquid crystal display. optical effect.

The technical scheme that the present invention takes in order to realize the above object is:

The invention provides a light guide device, which includes a body and a plurality of microstructure parts, the body has a refractive index n, and includes a light exit surface, a base surface and at least one light incident surface, the light incident surface is located on the light exit surface One side of the surface, the base surface corresponds to the light-emitting surface, and the distance between the base surface and the light-emitting surface is a thickness T; the microstructure parts are located on the base surface, and each microstructure part also includes a distance P A first base and a second base, an apex, a first reflective surface, a second reflective surface and a flat unit; wherein, the first reflective surface connects the first base and the apex, and the first There is a first distance L ₁ between the base and the apex, the second reflective surface connects the second base and the apex, and a second distance L ₂ exists between the second base and the apex, and the flat unit is located on the Between the second base and the first base, there is a distance S between the second base and the first base, and the following relationship is satisfied:

$\mathrm{<span\; class="notranslate">\; 0.47</span>}<span\; class="notranslate">\; <</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; *</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="P"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">P</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; PL</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 4.8</span>}<span\; class="notranslate">\; .</span>$

To achieve the above object, the present invention provides a backlight module, which includes at least one light source and a light guiding device, the light source is used to project a first optical path and a second optical path, and the light guiding device is used to receive the first optical path An optical path and the second optical path; wherein, the light guiding device includes a body and a plurality of microstructure parts, the body has a refractive index n, and includes a light exit surface, a base surface and at least one light incident surface, the The light-incident surface is located on one side of the light-emitting surface, the base surface corresponds to the light-emitting surface, and the distance between the base surface and the light-emitting surface is a thickness T; these microstructure parts are located on the base surface, and each microstructure part also includes a first base and a second base, a vertex, a first reflective surface, a second reflective surface and a flat unit separated by a width P; wherein the first reflective surface connects the first base and the vertex part, and the first base and the vertex are separated by a first distance L ₁ , the second reflective surface connects the second base and the vertex, and the second base and the vertex are separated by a second distance L ₂ , the flat unit is located between the second base and the first base, the second base is separated from the first base by a distance S, and satisfies the following formula:

$\mathrm{<span\; class="notranslate">\; 0.47</span>}<span\; class="notranslate">\; <</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; *</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="P"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">P</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; PL</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 4.8</span>}<span\; class="notranslate">\; .</span>$

Thus, the first optical path travels to the flat unit and is totally reflected in the body, and the second optical path is reflected to the light-emitting surface through the plurality of microstructure parts.

The above-mentioned light guide device, wherein the plurality of microstructure parts are convex structures or concave structures located on the base surface.

In the above-mentioned light guiding device, wherein, the relational expression of the light guiding device further includes: 4.5<n*T/S<46.

The above-mentioned light guiding device, wherein the lengths of the first distance L ₁ and the second distance L ₂ of the microstructure portion are not equal.

In the above-mentioned light guiding device, wherein, the cross-section of the first reflective surface or the second reflective surface is a straight line, a hyperbola, an elliptic curve or a parabola.

Therefore, the light guide device and the backlight module used in the embodiments of the present invention have the best optical uniformity, and the uniformity effect of the light is better, and the "dark band phenomenon" between light and dark will not occur.

Description of drawings

FIG. 1A is a schematic diagram of a backlight module and its optical path provided by Embodiment 1 of the present invention;

Fig. 1B is an optical effect diagram of the light guide device in Fig. 1A;

Fig. 1C is an optical effect diagram of light guide devices with different structural sizes;

Figure 1D is a schematic diagram of parameter combination for n=1.53, H/P=0.5 when the range of G is between 0.47 and 4.8;

Figure 1E is a schematic diagram of the combination of parameters for T=2mm and H/P=0.5 when the range of G is between 0.47 and 4.8;

Figure 1F is a schematic diagram of parameter combinations for T=2mm and n=1.53 when the range of G is 0.47-4.8;

FIG. 2 is a schematic diagram of a backlight module provided by Embodiment 2 of the present invention;

FIG. 3 is a schematic diagram of a backlight module provided by Embodiment 3 of the present invention;

Fig. 4 is a schematic diagram of the microstructure part provided by Embodiment 4 of the present invention;

Fig. 5 is a schematic diagram of the microstructure part provided by Embodiment 5 of the present invention;

Fig. 6 is a schematic diagram of a light guiding device provided by Embodiment 6 of the present invention;

FIG. 7 is a schematic diagram of a light guiding device provided by Embodiment 7 of the present invention.

In the accompanying drawings, the components represented by each label are listed as follows:

1, 2, 3: backlight module, 11, 21, 31: lampshade, 12, 22, 32: light source, 13, 23, 33, 43, 53, 63, 73: light guide device, 13A: light exit surface, 13B: Light incident surface, 13C, 33C: base surface, 131, 631, 731: main body, 132, 232, 332, 432, 632, 732: microstructure part, 1321: first base part, 1322: second base part, 1323: apex Department, 1324, 4324, 5324: first reflective surface, 1325, 4325, 5325: second reflective surface, 133, 233: flat unit;

θ: angle, T: thickness, P: width, H: depth, S: spacing, L ₁ : first distance, L ₂ : second distance, I ₁ : first optical path, I ₂ : second optical path .

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the implementation manner of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Please refer to FIG. 1A . FIG. 1A is a schematic diagram of a backlight module and its optical path provided by Embodiment 1 of the present invention. As shown in FIG. 1A , a backlight module 1 includes a light source 12 , a lampshade 11 and a light guiding device 13 . The light source 12 and the lampshade 11 are both arranged on the left side of the light guide device 13. The light source 12 is used to emit light. The left side enters the interior of the light guiding device 13 . The light guiding device 13 includes a body 131, a plurality of flat units 133 and a plurality of microstructure parts 132; the body 131 has a refractive index n, and includes a light-emitting surface 13A, a base surface 13C, and a light-incident surface 13B; these microstructures Part 132 is a convex structure located on the base surface 13C. As shown in the enlarged view of FIG. surface 1324 and a second reflective surface 1325 . Wherein, the material of the light guiding device 13 can be polyethylene terephthalate (Polyethylene Terephthalate, PET), polycarbonate (Polycarbonate, PC), tri-acetyl cellulose (Tri-acetyl Cellulose, TAC), polymethyl Methyl acrylate (Polymethylmethacrylate, PMMA), methyl methacrylate-styrene copolymer (Methylmethacrylate styrene), polystyrene (Polystyrene, PS) or cycloolefin copolymer (Cyclic Olefin Copolymer, COC), or at least two or more composed of said materials. The light-emitting surface 13A is located on the top of the light-guiding device 13, the light-incident surface 13B is located on the left side of the light-guiding device 13, and the base surface 13C is located below the light-guiding device 13, so the light-incident surface 13B is on the left side of the light-emitting surface 13A, and the base surface 13C Corresponding to the light-emitting surface 13A. The base surface 13C is separated by a thickness T from the light-emitting surface 13A. The microstructure portions 132 are located on the base surface 13C, and the distance between the first base portion 1321 and the second base portion 1322 is a width P. The first reflective surface 1324 connects the first base portion 1321 and the apex portion 1323, and the first base portion 1321 and the apex portion 1323 are separated by a first distance L ₁ ; the second reflective surface 1325 connects the second base portion 1322 and the apex portion 1323, and the second The base portion 1322 is separated from the apex portion 1323 by a second distance L ₂ . The flat unit 133 is located between the second base portion 1322 and the first base portion 1321 , and the distance of its section is the interval S, that is, the flat unit 133 is a horizontal area between two adjacent microstructure portions 132 . In this embodiment, the size and shape of each microstructure portion 132 are the same, and the spacing S of each flat unit 133 is also the same.

As shown in FIG. 1A , the light emitted by the light source 12 includes a first optical path I ₁ and a second optical path I ₂ , and the light guiding device 13 receives the first optical path I ₁ and the second optical path I ₂ of the light. Afterwards, the first optical path _I1 will travel to the plurality of flat units 133 and be totally reflected into the body 131; the second optical path _I2 will travel to the plurality of microstructure parts 132 and be reflected to the light-emitting surface 13A. That is to say, the first optical path _I1 and the second optical path _I2 are reflected by the flat unit 133 and the microstructure part 132 respectively, and then exit the light guide device 13 through the light exit surface 13A.

In a preferred embodiment, the light source 12 may be a cold cathode fluorescent lamp (Cold cathode fluorescent lamp, CCFL) or a light emitting diode (Light emitting diode, LED). In other embodiments, the light source 12 and the lampshade 11 can also be provided respectively on the left and right outer sides of the light guide device 13 according to requirements. In this way, the left and right sides of the light guiding device are light incident surfaces, and the light emitted by the two light sources can respectively enter the interior of the light guiding device from the left and right sides of the light guiding device.

For this structure, the inventors of the present invention conducted experiments on the optical effects of the structure of the light guide device 13 . Please refer to FIG. 1B . FIG. 1B is an optical benefit diagram of the light guide device in FIG. 1A . Wherein, the horizontal axis is different horizontal positions relative to the light guiding device 13 , and the vertical axis is the relative brightness of these different positions, and the relative brightness=average brightness/maximum brightness. As shown in FIG. 1B , the relative brightness of the light guide device 13 is related to the arrangement of the microstructure part 132 , and at the microstructure part 132 , the relative brightness value presents a peak. If the difference between the peak value and the average value is too large, it will cause "dark band phenomenon".

In order to improve the "dark band phenomenon" of traditional liquid crystal displays and improve the quality of its displayed images, the inventors of the present invention have made relative brightness calculations on the premise of different thicknesses T, different refractive indices n, and different spacings S of the light guide device 13. experiment. Please refer to FIG. 1C . FIG. 1C is an optical effect diagram of light guide devices with different structural sizes. As shown in FIG. 1C , no matter what the thickness T or the refractive index n is, as the spacing S of the microstructure portions 132 gradually decreases, the relative brightness thereof gradually increases. That is to say, when the pitch S of the microstructure parts 132 is smaller, it means that the light guide device 13 can be provided with more microstructure parts 132, that is, the higher the density of the microstructure parts 132, the "dark band phenomenon" of the liquid crystal display It is also less obvious. According to experience, when the relative brightness reaches above 0.4, people cannot distinguish the light and dark stripes with the naked eye, and the "dark band phenomenon" will no longer appear.

Therefore, in order to obtain the mathematical relationship between relative luminance and thickness T, spacing S, and refractive index n, the inventors of the present invention, after many experiments, found that thickness T, spacing S, and refractive index n can be combined into a dimensionless parameter U , which is used as the characteristic dimension of the light guide device; where:

U=n*T/S;

Here, the unit of the parameter U is dimensionless. Because the parameter U is a function of the thickness T, the spacing S and the refractive index n, the value of the parameter U of different materials can be measured through different thicknesses T and spacing S. Through experiments, it is found that when the dimensionless parameter U ranges from 4.5 to 46, the light guiding device 13 will have a better homogenization effect. Right now:

4.5＜n*T/S＜46 (1)

In addition, in addition to the structure of the light guide device 13 , the appearance and contour of the microstructure portion 132 are also important factors affecting the light extraction effect. Therefore, in addition to the dimensionless parameter U, the range of the aspect ratio of the microstructure part 132 will also affect the light output effect; as shown in the enlarged view of FIG. 1A, the aspect ratio is H/P, and the depth H is The distance of the microstructure part 132 in the vertical direction. According to experience, the aspect ratio of the microstructure part 132 should be between 0.05˜0.5. Right now:

0.05＜H/P＜0.5 (2)

In order to combine the size effect of the microstructure part 132 with the effect of the spacing S, the above-mentioned formula (1) and formula (2) are combined here, and the derivation is as follows:

Formula (1)*Formula (2);

→4.5*0.05＜(n*T/S)*(H/P)＜46*0.5;

$<span\; class="notranslate">\; \&Right\; Arrow;</span>\mathrm{<span\; class="notranslate">\; 0.225</span>}<span\; class="notranslate">\; <</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; T</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; *</span><span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}{\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; twenty\; three</span>}<span\; class="notranslate">\; ;</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

故Wherein, θ is the angle between the first reflective surface 1324 and the base surface 13C. In addition, since P, L ₁ , and L ₂ encircle to form a triangle, so

so

$<span\; class="notranslate">\; \&Right\; Arrow;</span>\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="P"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">P</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="P\; L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">P</figure-callout></span><figure-callout\; id="1"\; label="P\; L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">\; </figure-callout>}{\mathrm{<span\; class="notranslate">\; </span>}}_{}{\mathrm{<span\; class="notranslate">L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; ;</span>$

$<span\; class="notranslate">\; \&Right\; Arrow;</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="cos"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">cos</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}<span\; class="notranslate">\; =</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="P"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">P</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; PL</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; ;</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Substitute formula (4) into formula (3):

$<span\; class="notranslate">\; \&Right\; Arrow;</span>\mathrm{<span\; class="notranslate">\; 0.225</span>}<span\; class="notranslate">\; <</span><span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; T</span>}}{\mathrm{<span\; class="notranslate">\; S</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; *</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; P</span>}}\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="P"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">P</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; PL</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; twenty\; three</span>}<span\; class="notranslate">\; ;</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Divide the formula (5) into square root:

$<span\; class="notranslate">\; \&Right\; Arrow;</span>\mathrm{<span\; class="notranslate">\; 0.47</span>}<span\; class="notranslate">\; <</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; *</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="P"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">P</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; P</span>}{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 4.8</span>}<span\; class="notranslate">\; ;</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

Wherein, the lengths of the first distance L ₁ and the second distance L ₂ of the microstructure portion 132 may be unequal.

From the above derivation, it can be known that if the above formula (6) is satisfied, the light emission effect of the backlight module 1 can be made more uniform, and the "dark band phenomenon" of the light guide device 13 will no longer exist. Thus, through the definition of formula (6), the homogenization range of the light guide device 13 and the backlight module 1 used therefor can be obtained, so that the manufacturer can design an optimized light guide device 13 and the backlight module 1, There is no need to worry about the "dark band phenomenon" between light and dark.

The refractive index n, thickness T, spacing S, width P, first distance L ₁ , and second distance L ₂ of the above formula (6) can then define a homogenization index G:

$\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; =</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; *</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="P"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">P</figure-callout></span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="L"\; filenames="HSA00000317297900041.png,HSA00000317297900051.png"\; state="\{\{state\}\}">L</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; P</span>}{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; ;</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

Therefore, when the uniformity index G ranges from 0.47 to 4.8, the light guide device 13 will not produce the "dark band phenomenon".

In order to make it easier for those skilled in the art to clearly know the combination of various parameters of G, the relationship between the G value and the spacing S when the homogenization index G ranges from 0.47 to 4.8 is further listed here in a graph. Please refer to FIG. 1D . FIG. 1D is a schematic diagram of parameter combinations for n=1.53 and H/P=0.5 when G ranges from 0.47 to 4.8. As shown in FIG. 1D , when the thickness T of the light guiding device 13 is larger, the uniformity index G is also higher. In addition, under the condition of the same thickness T, when the distance S is smaller, the uniformity index G will be higher. The higher the homogenization index G, the better the homogenization effect of the light guiding device 13 , and the less "dark band phenomenon" will occur. It can be seen from this figure that when the thickness T of the light guide device 13 is 1mm, the G value is about 1.1-2.9; when the thickness T is 2mm, the G value is about 1.5-3.9; when the thickness T is 3mm, the G value is about 2~4.8.

Please refer to FIG. 1E . FIG. 1E is a schematic diagram of parameter combinations for T=2mm and H/P=0.5 when the range of G is 0.47-4.8. As shown in FIG. 1E , when the light guide device 13 uses different materials, the difference in the uniformity index G caused by the different refractive indices n is not large. Same as the trend in Figure 1D, when the spacing S is smaller, the homogenization index G will be higher. It can be known from this figure that no matter what kind of material the light guide device 13 is made of, its G value is about 1.5-3.9.

Please refer to FIG. 1F . FIG. 1F is a schematic diagram of parameter combinations for T=2mm and n=1.53 when G ranges from 0.47 to 4.8. As shown in FIG. 1F , when the aspect ratio of the light guiding device 13 is larger, the value of H/P is larger, and the uniformity index G is also higher. Also, when the spacing S is smaller, the homogenization index G will be higher. When the aspect ratio H/P of the light guiding device 13 is 0.05, its G value is about 0.5-1.2; when the aspect ratio H/P of the light guiding device 13 is 0.25, its G value is about 1.1-2.8; When the aspect ratio H/P of the light guiding device 13 is 0.50, its G value is about 1.6-4; when the aspect ratio H/P of the light guiding device 13 is 0.75, its G value is about 2-4.8.

Of course, there are other embodiments of the present invention. Please refer to FIG. 2 . FIG. 2 is a schematic diagram of a backlight module according to Embodiment 2 of the present invention. As shown in FIG. 2 , the backlight module 2 includes a light source 22 , a lampshade 21 and a light guiding device 23 . Wherein, similar structures will not be repeated here. The cross sections of the multiple microstructure parts 232 of the backlight module 2 are isosceles obtuse triangles with the same shape and the same size. The cross-sectional spacing S of the flat units 233 between two adjacent microstructure portions 232 is not equal; as shown in FIG. 2 , the spacing S of the plurality of flat units 233 becomes smaller as it goes to the right. Because, near the light source 22, the density of the light (not shown) is relatively high, it is necessary to reflect the light through a flat unit 233 with a larger area, so that the light can be transmitted to the right side of the light guide device 23; The light energy of device 23 just can be uniform.

Please refer to FIG. 3 . FIG. 3 is a schematic diagram of a backlight module according to Embodiment 3 of the present invention. As shown in FIG. 3 , the backlight module 3 includes a light source 32 , a lampshade 31 and a light guiding device 33 . Wherein, the plurality of microstructure parts 332 of the backlight module 3 are concave structures located on the base surface 33C, and these microstructure parts 332 can also be used to reflect light, so that the light inside the light guide device 33 (not shown in this figure) is evenly distributed. pass to the right.

Please refer to FIG. 4 . FIG. 4 is a schematic diagram of the microstructure part of Embodiment 4 of the present invention. As shown in FIG. 4 , the first reflective surface 4324 of the light guide device 43 is a plane, so the cross section of the first reflective surface 4324 is a straight line. The second reflective surface 4325 of the light guide device 43 is a slightly downwardly convex curved surface, so the cross-section of the second reflective surface 4325 can present a hyperbola, an elliptic curve or a parabola. Thus, the light guiding device 43 can pass through the first reflective surface 4324 and the second reflective surface 4325 with different contours of the microstructure portion 432 , so that the reflected light can achieve a better light guiding effect.

Please refer to FIG. 5 . FIG. 5 is a schematic diagram of the microstructure part of Embodiment 5 of the present invention. As shown in FIG. 5 , the first reflective surface 5324 of the light guide device 53 is a slightly upwardly concave curved surface, and the second reflective surface 5325 is a slightly downwardly convex curved surface. Thus, this embodiment can also achieve the aforementioned effects.

Please refer to FIG. 6 . FIG. 6 is a schematic diagram of a light guide device according to Embodiment 6 of the present invention. As shown in FIG. 6 , the light guiding device 63 includes a plurality of microstructure parts 632 , and these microstructure parts 632 are in the shape of triangular prism columns, and are respectively distributed on different heights of the body 631 . In a preferred embodiment, these microstructure parts 632 are distributed in a manner of periodic ups and downs.

Please refer to FIG. 7 . FIG. 7 is a schematic diagram of a light guide device according to Embodiment 7 of the present invention. As shown in FIG. 7 , the light guide device 73 includes a plurality of microstructure parts 732 that are horizontally distributed at the same height of the body 731 , and each microstructure part 732 is in the shape of a repeatedly curved arc.

To sum up, the light guide device and the backlight module used in the embodiment of the present invention can obtain the optical efficacy of structures with different sizes by making the size characteristics of the light guide device and the microstructure part non-dimensional. As mentioned above, no matter what kind of embodiment, when the size characteristics of the light guide device and the microstructure part meet the range of formula (6), the light guide device has the best optical uniformity, and its light The homogenization effect is better, and there will be no "dark band phenomenon" between light and dark.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (8)

1. A light guiding device, characterized in that it comprises: A body, the body has a refractive index n, and includes a light exit surface, a base surface and at least one light incident surface, the light incident surface is located on one side of the light exit surface, the base surface corresponds to the light exit surface, and the base The distance between the surface and the light-emitting surface is a thickness T; A plurality of microstructure parts, the microstructure parts are located on the base surface, each microstructure part also includes: a first base and a second base separated by a width P; a vertex; a first reflective surface, connecting the first base and the apex, and the first base and the apex are separated by a first distance L ₁ ; a second reflective surface, connecting the second base and the apex, and the second base and the apex are separated by a second distance L ₂ ; A flat unit is located between the second base in one microstructure and the first base of an adjacent microstructure, the second base is separated from the first base by a distance S, and the relational expression is as follows: $\mathrm{<span\; class="notranslate">\; 0.47</span>}<span\; class="notranslate">\; <</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; *</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; PL</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 4.8</span>}<span\; class="notranslate">\; .</span>$ 2 . The light guide device according to claim 1 , wherein the plurality of microstructure portions are convex structures or concave structures on the base surface. 3 . 3 . The light guide device according to claim 1 , wherein the relational expression of the light guide device further comprises: 4.5<n*T/S<46. 4 . The light guiding device according to claim 1 , wherein the lengths of the first distance L ₁ and the second distance L ₂ of the microstructure portion are not equal. 5 . The light guiding device according to claim 1 , wherein a cross section of the first reflective surface or the second reflective surface is a straight line, a hyperbola, an elliptic curve or a parabola. 6. A backlight module, characterized in that, comprising: at least one light source for projecting a first optical path and a second optical path; A light guiding device for receiving the first optical path and the second optical path, the light guiding device further includes: A body, the body has a refractive index n, and includes a light exit surface, a base surface and at least one light incident surface, the light incident surface is located on one side of the light exit surface, the base surface corresponds to the light exit surface, and the base The distance between the surface and the light-emitting surface is a thickness T; A plurality of microstructure parts, the microstructure parts are located on the base surface, each microstructure part also includes: a first base and a second base separated by a width P; a vertex; a first reflective surface, connecting the first base and the apex, and the first base and the apex are separated by a first distance L ₁ ; a second reflective surface, connecting the second base and the apex, and the second base and the apex are separated by a second distance L ₂ ; A planar unit, located between the second base in one microstructure and the first base of an adjacent microstructure, the second base is separated from the first base by a distance S; Wherein, the first optical path travels to the flat unit and is totally reflected in the body, and the second optical path is reflected to the light-emitting surface through the plurality of microstructure parts, and satisfies the following equation: $\mathrm{<span\; class="notranslate">\; 0.47</span>}<span\; class="notranslate">\; <</span>\sqrt{\frac{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; T</span>}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{\mathrm{<span\; class="notranslate">\; S</span>}<span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; *</span>\sqrt{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; PL</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 4.8</span>}<span\; class="notranslate">\; .</span>$ 7. The backlight module according to claim 6, wherein the lengths of the first distance _L1 and the second distance _L2 of the microstructure part are not equal. 8 . The backlight module according to claim 6 , wherein a section of the first reflective surface or the second reflective surface is a straight line, a hyperbola, an elliptic curve or a parabola.

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