TWI400531B - Optical plate and backlight module using the same - Google Patents

Description

Backlight module and optical plate thereof

The invention relates to a backlight module and an optical plate thereof, in particular to a backlight module for liquid crystal display and an optical plate thereof.

Referring to FIG. 1 , a conventional direct type backlight module 100 includes a frame 11 , a plurality of light sources 12 disposed inside the frame 11 , and a diffusion plate 13 disposed above the light source 12 .

In use, light generated by the complex light source 12 can be diffused after entering the diffuser plate 13. However, after being diffused through the diffusion plate 13, the angle of light emitted from the diffusion plate 13 becomes disordered, so that the brightness thereof is not high in a specific viewing angle range; and since the light source 12 transmits more light directly above it, diffusion It is often difficult for the plate 13 to directly diffuse the light from the light source 12 uniformly, so that the light emitted from the diffusing plate 13 is likely to cause residual light source, that is, a region where light intensity is different.

In order to improve the brightness of the backlight module 100 in a specific viewing angle range and avoid the generation of residual light of the light source, thereby improving the uniformity of the light emitted by the backlight module 100, an optical plate 10 and an upper diffusion are generally disposed above the diffusion plate 13. Sheet 14. As shown in FIG. 2, the optical plate 10 includes a transparent substrate 101 and a ruthenium layer 103 formed on the transparent substrate 101. The ruthenium layer 103 has a plurality of elongated V-shaped projections 105 thereon. Length of optical plate 10 The strip-shaped V-shaped protrusions 105 can cause the emitted light to be concentrated to a certain extent, thereby improving the brightness of the backlight module 100 within a specific viewing angle range. The upper diffusion sheet 14 can further diffuse light emitted from the optical plate 10.

However, when light is transmitted through the optical plate 10 and the upper diffusion sheet 14, part of the light is absorbed to cause light loss; and there is an air layer between the optical plate 10 and the upper diffusion sheet 14, which increases light during transmission. The number of interfaces increases the interface loss of light transmission and reduces the brightness of the light.

In view of the above situation, it is necessary to provide a backlight module having a high brightness and an optical plate thereof.

A backlight module includes a frame, a light source, and an optical plate. A light source is located within the frame and an optical plate is positioned above the light source. The optical plate includes a first surface and a second surface opposite the first surface. A plurality of microstructures are formed on the first surface. The outline of the microstructure on the first surface encloses an olive shape, and the long axis and the short axis of the olive form respectively establish an XYZ three-dimensional rectangular coordinate system for the X axis and the Y axis, and the y coordinate value of any point on the contour line and x The coordinate values satisfy the following relationship: The projection of the protrusion on the XZ plane is a closed pattern surrounded by a ridge line and an X-axis, wherein the z-coordinate value and the x-coordinate value of any point on the ridge line satisfy the following relationship: Wherein, S, y ₀ , A, x _c , w ₁ , w ₂ , w ₃ and θ are all constants, and the ranges are respectively -13.549 < y ₀ < -9.549, -1.0 < x _c < 1.0, 62.754 < A <72.754, 45.72 < w ₁ < 280.2, 8.01 < w ₂ < 53.03, 8.01 < w ₃ < 53.03, 45 ° < θ < 175 °, 0.1 < S < 3, the second surface is a plane.

An optical plate includes a first surface and a second surface opposite the first surface. A plurality of microstructures are formed on the first surface. The outline of the microstructure on the first surface encloses an olive shape, and the long axis and the short axis of the olive form respectively establish an XYZ three-dimensional rectangular coordinate system for the X axis and the Y axis, and the y coordinate value of any point on the contour line and x The coordinate values satisfy the following relationship: The projection of the protrusion on the XZ plane is a closed pattern surrounded by a ridge line and an X-axis, wherein the z-coordinate value and the x-coordinate value of any point on the ridge line satisfy the following relationship: Wherein, S, y0, A, xc, w1, w2, w3 and θ are all constants, and the ranges are -13.549<y0<-9.549, -1.0<xc<1.0, 62.754<A<72.754, 45.72<w1< 280.2, 8.01 < w2 < 53.03, 8.01 < w3 < 53.03, 45 ° < θ < 175 °, 0.1 < S < 3, the second surface is a plane.

The optical plate can refract, reflect and diffract light incident thereon, thereby causing specific diffusion to form a uniform light exiting surface. The raised structure on the first surface can also converge the exit angle of the outgoing light to enhance the brightness of the light.

The backlight module and the optical plate of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

Referring to FIG. 3, an optical plate 20 according to a preferred embodiment of the present invention has a first surface 201 and a second surface 203 opposite the first surface 201. Wherein, the first surface 201 is formed with a plurality of micro-structures 2011 arranged in a plurality of arrays. In this embodiment, the microstructures 2011 are protrusions extending outward from the first surface 201, and the second surface 203 is a plane.

The optical plate 20 is made of a transparent material. The transparent material is one or a mixture of one or more of polymethyl methacrylate, polycarbonate, polystyrene, and styrene-methyl methacrylate copolymer.

Referring to FIGS. 4-7, the microstructure 2011 is surrounded by a bottom surface 2012 and two side surfaces 2013, and the two side surfaces 2013 intersect at the top of the microstructure 2011 to form a ridge line 2014. The bottom surface 2012 is generally olive-shaped, which is surrounded by two contour lines 2015 of the microstructure 2011 on the first surface 201. The bottom surface 2012 has a long axis 2016 and a short axis 2017. The long axis 2016 is the X axis, the short axis 2017 is the Y axis, and the intersection of the long axis 2016 and the short axis is the origin to establish a three-dimensional rectangular coordinate system. The direction of the Z axis points to the extension direction of the microstructure 2011, and the microstructure 2011 itself is relatively Both the XZ plane and the YZ plane are symmetrical. In the above three-dimensional Cartesian coordinate system, the trajectory of the contour line 2015 can be described by the following equation: .

In the above equation, y is the coordinate value of any point on the contour line 2015 on the Y-axis, and x is the coordinate value of the point on the X-axis. The rest are constants, wherein the preferred range of x and each constant is as follows: -13.549 < y < -9.549, -213.5 < x < 213.5, -1.0 < xc < 1.0, 62.754 < A < 72.754, 45.72 < w1 < 280.2, 8.01 <w2<53.03, 8.01<w3<53.03, 0.1<S<3.

Since the microstructure 2011 is symmetric about the XZ axis, the ridge line 2014 extends in the XZ plane, and the projection of the ridge line 2014 on the XZ plane is itself. The microstructure 2011 is divided into triangles by the plane parallel to the YZ plane (Fig. 5), and the apex angle of the triangle is denoted by θ , then the Z-axis coordinate value z and its Y for any point on the microstructure 2011 ridge line 2014 The axis coordinate value y has the following relationship:

The above formula is the relationship between the Z coordinate and the X coordinate of any point on the ridge line 2014, that is, the curved trajectory of the ridge line 2014 projected on the X-Z plane (Fig. 6).

Wherein, the preferred range of x and each constant in the above formula is as follows: -13.549 < y < -9.549, -213.5 < x < 213.5, -1.0 < xc < 1.0, 62.754 < A < 72.754, 45.72 < w1 < 280.2, 8.01 W2<53.03, 8.01<w3<53.03, 45°<θ<175°, 0.1<S<3.

The top of the microstructure 2011 is at least partially planarized, or curved, to enhance the overall strength of the optical plate 20. At this time, the projection of the ridge line 2014 on the X-Z plane satisfies the trajectory equation of the ridge line 2014 described above.

The microstructures 2011 on the optical plate 20 may be formed on the first surface 201 with a transparent material, or may be formed in the mother mold by a corresponding groove, and integrally molded by injection molding.

In use, the second surface 203 of the optical plate 20 is adjacent to the light source as a light incident surface, and the first surface 201 is away from the light source as a light exit surface. After the light emitted by the light source enters from the second surface 203, a specific refraction occurs in the microstructure 2011. , diffraction and total reflection, converge the angle of light out of the light, so that the brightness of the light increases.

Of course, the inclination angle of the ridges 2014 of the microstructures 2011 at the ends of the Y-Z may be different from the X-axis, so that the microstructures 2011 have an asymmetrical shape with respect to the Y-Z plane.

The structure of the microstructure 2011 is not limited to the protrusions, and may be the same shape, the groove extending from the first surface 201 toward the inside of the optical plate 20. At this time, the outline of the microstructure 2011 on the first surface 201 is the same as when it is convex, the ridge line 2014 of the microstructure 2011 will be located below the first surface 201, and the Z axis is directed to the second surface 203. When the microstructure 2011 is a groove, the effect of the optical plate 20 is substantially the same as that when the microstructure 2011 is a protrusion.

Referring to FIG. 8 , a backlight module 200 according to a preferred embodiment of the present invention includes an optical plate 20 , a frame 21 , and a light source 22 . The light source 22 is located in the frame 21 , and the optical plate 20 is located in the light source 22 . Above.

The frame 21 may be made of metal or plastic having high reflectivity or metal or plastic coated with a high reflectivity coating.

The light source 22 can be a complex line source or a plurality of point sources. In this embodiment, the plurality of line sources are arranged closely. Preferably, the plurality of line sources are a plurality of cold cathode fluorescent lamps.

The second surface 203 of the optical plate 20 in the backlight module 200 faces the light source 22 as a light incident surface and the first surface 201 away from the light source 22 as a light exit surface. The plurality of cold cathode fluorescent lamps are arranged closely, and the emitted light is incident on the optical plate 20 to cause specific optical effects such as refraction, scattering, reflection, and diffraction, thereby allowing the light emitted from the optical plate 20 to be specifically diffused. Thereby, an exit surface with a relatively uniform brightness is formed. among them, The microstructure 2011 structure on the first surface 201 can converge the exit angle of the light, increasing the brightness of the exiting light within a particular range. It can be seen that the backlight module 200 can improve the light uniformity of the backlight module and enhance the brightness of the light. Of course, when the light source 22 is a complex point light source, the plurality of point light sources are closely arranged in an array, and the effect of using the plurality of line sources can be similarly achieved. Preferably, the plurality of point sources are complex LEDs.

In order to further verify the effect of the optical plate 20, nine test points are taken on the light-emitting surfaces of the backlight module 100 and the backlight module 200 to perform a light-brightness comparison test under the same light source. The test results are shown in the following table.

As can be seen from the above table, at each test point, the brightness of the backlight module 200 is greater than that of the backlight module 100, and the brightness is improved by at least 14%, and the effect is obvious.

When the distance between the light sources 22 is large, a diffusion plate can be added between the optical plate 20 and the light source 22 of the backlight module 200 of the present invention, so that the light can be evenly diffused and the light output of the whole backlight module can be improved. Sex.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

100, 200‧‧‧ backlight module

10, 20‧‧‧ Optical board

101‧‧‧Substrate

103‧‧‧稜鏡

105‧‧‧Long V-shaped bulge

11, 21‧‧‧ framework

12, 22‧‧‧ Light source

13‧‧‧Diffuser

201‧‧‧ first surface

2011‧‧‧Microstructure

2012‧‧‧ bottom

2014‧‧‧ ridge line

2015‧‧‧ contour

2016‧‧‧ long axis

2017‧‧‧Short axis

203‧‧‧ second surface

1 is a schematic cross-sectional view of a conventional backlight module.

2 is a perspective view of an optical plate of the backlight module shown in FIG. 1.

3 is a perspective view of an optical plate according to a preferred embodiment of the present invention.

Figure 4 is a perspective view showing the projection of the optical plate shown in Figure 3.

Figure 5 is a cross-sectional view of the projection of the optical plate shown in Figure 3 on the Y-Z plane.

Figure 6 is a projection view of the projection of the optical plate shown in Figure 3 on the X-Z plane.

Figure 7 is a cross-sectional view of the projection of the optical plate shown in Figure 3 on the X-Y plane.

Fig. 8 is a schematic view showing a backlight module using the optical plate shown in Fig. 3.

20‧‧‧Optical board

201‧‧‧ first surface

2011‧‧‧Microstructure

203‧‧‧ second surface

Claims (13)

A backlight module includes a frame, a light source, and an optical plate, wherein the light source is located in the frame, the optical plate is located above the light source, and the optical plate comprises a first surface and a second surface opposite to the first surface, the first The two surfaces face the light source, and the improvement is that: the first surface is formed with a plurality of microstructures, and the outline of the plurality of microstructures on the first surface is surrounded by an olive shape, wherein the long axis and the short axis of the olive shape are respectively The X-axis and the Y-axis establish an XYZ three-dimensional Cartesian coordinate system, and the microstructure extends along the Z-axis direction, and the y coordinate value and the x coordinate value of any point on the contour line satisfy the following relationship: The projection of the microstructure on the XZ plane is a closed pattern surrounded by a ridge line and an X-axis, wherein the z-coordinate value and the x-coordinate value of any point on the ridge line satisfy the following relationship: _{Wherein, S, y 0, A,} x c, w 1, w 2, w 3 and θ are constants, respectively, range _{-13.549 <y 0 <-9.549, -1.0} <x c <1.0,62.754 <A <72.754, 45.72 < w ₁ < 280.2, 8.01 < w ₂ < 53.03, 8.01 < w ₃ < 53.03, 45 ° < θ < 175 °, 0.1 < S < 3, the second surface is a plane. The backlight module of claim 1, wherein the micro-junction The protrusion is formed to protrude outward from the first surface, and the contour of the microstructure on the first surface is the bottom surface of the protrusion. The backlight module of claim 1, wherein the microstructure is a groove extending from the first surface into the optical plate. The backlight module of claim 3, wherein the light source is a plurality of line sources, and the plurality of line sources are closely arranged. The backlight module of claim 1, wherein the microstructure is cut into an isosceles triangle by a plane parallel to an arbitrary parallel Y-Z plane. The backlight module of claim 1, wherein at least a portion of the top of the microstructure is planarized. The backlight module of claim 1, wherein at least a portion of the top of the microstructure is rounded. An optical plate comprising a first surface and a second surface opposite to the first surface, wherein the first surface is formed with a plurality of microstructures, and the plurality of microstructures are contoured on the first surface The contour line is formed into an olive shape, and the long axis and the short axis of the olive form respectively form an XYZ three-dimensional rectangular coordinate system for the X axis and the Y axis, and the microstructure extends along the Z axis direction, and the y coordinate of any point on the contour line The value and the x coordinate value satisfy the following relationship: The projection of the microstructure on the XZ plane is a closed pattern surrounded by a ridge line and an X-axis, wherein the z-coordinate value and the x-coordinate value of any point on the ridge line satisfy the following relationship: Wherein, S , y ₀ , A , x _c , w ₁ , w ₂ , w ₃ and θ are all constants, and the ranges are -13.549< y ₀ <-9.549, -1.0<x _c <1.0, 62.754<A, respectively. <72.754, 45.72 < w ₁ < 280.2, 8.01 < w ₂ < 53.03, 8.01 < w ₃ < 53.03, 45 ° < θ < 175 °, 0.1 < S < 3, the second surface is a plane. The optical plate of claim 8, wherein the microstructure is a protrusion extending outward from the first surface, and the outline of the microstructure on the first surface is the bottom surface of the protrusion. The optical sheet of claim 8, wherein the microstructure is a groove extending from the first surface into the optical plate. The optical sheet of claim 9, wherein the microstructure is cut into an isosceles triangle by a plane parallel to the plane of any parallel Y-Z plane. The optical sheet of claim 9, wherein at least a portion of the top of the microstructure is planarized. The optical sheet of claim 9, wherein at least a portion of the top of the microstructure is rounded.