CN1949048A - Backlight module and light guiding plate thereof - Google Patents

Abstract

The invention relates to light guiding board and back light die set. The light guiding board includes one light exiting face, one back face, many light entering faces. The geometric centre of the back face is inner depressed towards the light guiding board; its base line forms one cone-shaped body with the geometric center to generate many inclined planes each which respectively forms many V type crowning which is parallel with the back face, has the same shape; and the longer its distance from the back face, the bigger its density and size are. The invention also supplies back light die set which has the advantages of high emitted light brightness uniformity.

Description

Backlight module and its light guide plate

【Technical field】

The invention relates to a backlight module and its light guide plate, in particular to a backlight module and its light guide plate using side lighting.

【Background technique】

Since the liquid crystal itself of the liquid crystal display panel does not have light-emitting characteristics, in order to achieve the display effect, it is necessary to provide the liquid crystal display panel with a surface light source device, such as a backlight module, whose function is to supply a surface light source with sufficient brightness and uniform distribution to the liquid crystal display panel.

The side-mounted backlight module in the prior art is mainly composed of a light source, a light guide plate, a reflection plate, a diffuser plate and a prism plate. The light source can be arranged on at least one side of the light guide plate and emit light to the light guide plate. The function of the light guide plate is to guide the direction of light transmission, so that the light is uniformly emitted from the light-emitting surface of the light guide plate. utilization rate. The diffuser plate and the prism plate are sequentially arranged relative to the light-emitting surface of the light guide plate to make the distribution of light emitted from the light guide plate more uniform, thereby improving the brightness and uniformity of the liquid crystal display panel.

However, the liquid crystal display using the side-mounted backlight module is generally only widely used in small-sized liquid crystal displays, such as mobile phones, because of its low brightness. Generally, large-sized liquid crystal displays have a demand for light weight and high brightness, such as notebook computers, liquid crystal televisions and other fields.

Please refer to Fig. 1, in order to make the side-mounted backlight module achieve the effect of light weight and high brightness, the prior art provides a backlight module 10, which includes four cold cathode fluorescent lamps (Cold Cathode Fluorescent Lamp, CCFL) 11 and a The light guide plate 12 , the light guide plate 12 includes a light exit surface 122 , a bottom surface 124 opposite to the light exit surface 122 , and four light incident surfaces 121 connecting the light exit surface 122 and the bottom surface 124 . The geometric center of the bottom surface 124 is recessed into the light guide plate 12 , so that the thickness of the light guide plate 12 gradually becomes thinner from the edge to the geometric center. The geometric center and the four bases of the bottom surface 124 form a four-sided pyramid, so that the bottom surface 124 forms four slopes. The four inclined surfaces face the four light-incident surfaces 121 respectively. The four CCFLs 11 are respectively close to the four light incident surfaces 121 and irradiate light thereto.

However, since the bottom surface of the light guide plate 12 has a concave structure, it will affect the uniformity of the emitted light on the light emitting surface. Moreover, the design of using four CCFLs 11 to irradiate light to the four light-incident surfaces 121 has the following disadvantages: the luminance of the two ends of the CCFL 11 is lower than that of the middle part, so that dark areas are easily formed at the four corners of the light guide plate 12 .

In view of this, it is necessary to provide a light guide plate and a backlight module with high uniformity of outgoing light, light weight and high brightness.

【Content of invention】

A light-weight, high-brightness light guide plate and a backlight module using the light guide plate will be described below with examples.

A light guide plate, which includes a light exit surface, a bottom surface opposite to the light exit surface, and a plurality of light incident surfaces connecting the light exit surface and the bottom surface, the geometric center of the bottom surface is recessed into the light guide plate, and the geometric The center forms a cone with multiple bases of the bottom surface, so that the bottom surface forms multiple slopes, wherein each slope forms a plurality of V-shaped protrusions parallel to the corresponding base, and the V-shaped protrusions have the same shape , and the farther away from the bottom edge, the denser the arrangement density of the V-shaped protrusions, and the larger the size.

A backlight module, which includes a plurality of light sources and a light guide plate, the light guide plate includes a light exit surface, a bottom surface opposite to the light exit surface, and a plurality of light incident surfaces connecting the light exit surface and the bottom surface, the multiple Each of the light sources is close to the multiple light incident surfaces, the geometric center of the bottom surface is recessed into the light guide plate, and the geometric center and the multiple bottom edges of the bottom surface form a cone, so that the bottom surface forms multiple slopes, each of which The two slopes respectively form a plurality of V-shaped protrusions parallel to the corresponding bottom edges. The V-shaped protrusions have the same shape, and the farther they are from the bottom edge, the denser the arrangement density of the V-shaped protrusions is, and the larger the size is.

Compared with the prior art, the light guide plate has the following advantages: a plurality of V-shaped protrusions are formed from the bottom edge of the slope toward the geometric center, from sparse to dense, and from small to large. To strengthen the compression effect of the geometric center and its surroundings on the beam emission angle, thereby effectively improving the uniformity of the light output brightness of the entire light guide plate, and the backlight module using the light guide plate also has the advantage of high uniformity of light output brightness.

【Description of drawings】

FIG. 1 is a schematic structural diagram of a side-mounted backlight module in the prior art.

FIG. 2 is a schematic diagram of a three-dimensional structure of a backlight module according to a preferred embodiment 1 of the present invention.

Fig. 3 is a schematic cross-sectional view along line III-III of Fig. 2 .

FIG. 4 is an enlarged schematic view of part IV of FIG. 3 .

FIG. 5 is a schematic top view of a backlight module according to a second preferred embodiment of the present invention.

Fig. 6 is a schematic cross-sectional view along line VI-VI of Fig. 5 .

【Detailed ways】

The light guide plate of the present invention and the backlight module using the light guide plate will be further described in detail below with reference to the drawings and multiple embodiments.

Please refer to FIG. 2 and FIG. 3 together. The first preferred embodiment of the present invention provides a backlight module 20 . The backlight module 20 includes four linear light sources 21 and a light guide plate 22. The light guide plate 22 includes: a light-emitting surface 222, a bottom surface 224 opposite to the light-emitting surface 222, and four holes connecting the light-emitting surface 222 and the bottom surface 224. A light incident surface 221. The four line light sources 21 are respectively close to the four light incident surfaces 221 and irradiate incident light thereto.

The geometric center of the bottom surface 224 is recessed into the light guide plate 22 , so that the thickness of the light guide plate 22 gradually becomes thinner from the edge to the geometric center. The geometric center and four bases of the bottom surface 224 form a quadrangular pyramid, so that the bottom surface 224 forms four slopes. The four slopes face the four light incident surfaces 221 respectively, and each slope forms an acute angle with the corresponding light incident surface 221 .

The slopes of the bottom surface 224 respectively form a plurality of V-shaped protrusions 228 parallel to the corresponding bottom sides. The V-shaped protrusions 228 on each slope have the same shape, and the farther away from the bottom edge, the denser the arrangement density of the V-shaped protrusions 228 and the larger the size. The plurality of V-shaped protrusions 228 are V-shaped elongated bumps of different sizes. Each V-shaped protrusion 228 has a uniform height along the length direction.

Please refer to FIG. 3 and FIG. 4 together, the section of the light guide plate 22 is taken along the line III-III perpendicular to the light incident surface 221 . Since the plurality of V-shaped protrusions 228 have the same shape, the cross-section of each V-shaped protrusion 228 has the same first base angle θ1 , second base angle θ2 and top angle θ3 adjacent to the corresponding base. The value range of the first base angle θ1 is 5-60 degrees, the value range of the second base angle θ2 is 60-170 degrees, and the value range of the apex angle θ3 is 60-170 degrees. The distance between adjacent V-shaped protrusions 228 ranges from 0.001 mm to 3.0 mm. The height of the V-shaped protrusion 228 ranges from 0.001 mm to 1.0 mm.

Since the geometric center of the bottom surface 224 is far away from the four light incident surfaces 221 , the light output brightness of the corresponding position on the light exit surface 222 of the light guide plate 22 is smaller than that of the position close to the corresponding light incident surface 221 . However, a plurality of V-shaped protrusions 228 are formed from the bottom edge of the inclined plane to the geometric center direction, from sparse to dense, and from small to large, which can strengthen the compression effect of the geometric center and its surrounding parts on the beam exit angle. , so as to effectively improve the brightness uniformity of the entire light guide plate. In addition, by properly selecting the first base angle θ1, the second base angle θ2, and the apex angle θ3 of the V-shaped structure 228, it is possible to control the angle of the outgoing light beam of the light guide plate, so that most of the light beam is perpendicular to the light-emitting surface 222. Direction shoots out.

The light guide plate 22 of this embodiment can be made of light-weight transparent resin materials, such as acrylic resin, polycarbonate, polyethylene resin, and the like. The linear light source 21 in this embodiment can be a cold cathode fluorescent tube.

The light emitting surface 222 is a discharge fog surface. The degree of atomization at the four corners of the light-emitting surface is greater than that at its adjacent positions, which is used to solve the problem that the brightness of the light at both ends of the line light source 21 is lower than that at the middle part, so that dark areas are easily formed at the four corners of the light guide plate 22 The problem.

It can be understood that the light guide plate of the present invention can also be pentagonal, hexagonal or other shapes, and its bottom surface forms a five-sided, hexagonal or other polygonal cone, and each slope of the bottom surface faces the light guide plate respectively. Multiple light incident surfaces of the light panel. Correspondingly, the backlight module of the present invention also includes multiple light sources that cooperate with multiple light incident surfaces of the light guide plate.

Please refer to FIG. 5 and FIG. 6 together. The second preferred embodiment of the present invention provides a backlight module 40 . The backlight module 40 is similar to the backlight module 20 of the first preferred embodiment, the difference is that a reflector 44 is added. The backlight module 40 includes four line light sources 41 and a light guide plate 42 . The light guide plate 42 includes a light emitting surface 422 , four light incident surfaces 421 , a bottom surface 424 and a plurality of V-shaped protrusions 428 .

The reflector 44 is a frame structure surrounding the light guide plate 42 and the plurality of line light sources 41 . Four inner sides of the reflector 44 facing the light incident surface 421 of the light guide plate 42 respectively form a rectangular groove 441 for accommodating the four linear light sources 41 . Wherein, the upper and lower sides 442 , 443 of the rectangular groove 441 can clamp the light guide plate 42 . The reflector 44 is an integral structure.

Since the reflector 44 has an integral frame structure, it has better mechanical strength and can provide better protection for the four linear light sources 41 and the light guide plate 42 . The reflector 44 is made of a metal material with good ability to reflect light, such as copper or aluminum. In addition, the reflector 44 can also form a total reflection film on the inner side of the reflector 44 facing the light incident surface of the light guide plate, so as to further improve the utilization rate of light energy.

It can be understood that the linear light source of the present invention can also use L-shaped CCFL tubes instead of linear CCFL tubes, and can also use multiple light-emitting diode point light sources. In addition, the cross section of the reflector of the present invention can also be a frame structure with a semicircular curved surface.

The light guide plate of the present invention has the following advantages: the design of a plurality of V-shaped protrusions from sparse to dense and from small to large is formed from the bottom edge of the slope toward the geometric center, which can strengthen the geometric center and its structure. The compression effect of the surrounding part on the beam output angle effectively improves the uniformity of the light output brightness of the entire light guide plate. Moreover, the light-emitting surface is a discharge fog surface, and the degree of atomization at its four corners is greater than that at its adjacent positions, which can solve the problem that the four ends of the light guide plate are caused by the low brightness of the two ends of the line light source compared with the middle part. The problem of dark areas easily formed in the corners further improves the uniformity of the light output brightness. In addition, the integrated reflector has better mechanical strength and can provide better protection for the multiple line light sources and the light guide plate. Therefore, the backlight module of the present invention has the advantages of high uniformity of light emitting brightness and high mechanical strength.

In addition, those skilled in the art can also make other changes within the spirit of the present invention. Of course, these changes made according to the spirit of the present invention should be included in the scope of protection claimed by the present invention.

Claims (12)

1. A light guide plate, comprising: a shiny surface; a bottom surface opposite to the light-emitting surface; and A plurality of light-incident surfaces connecting the light-emitting surface and the bottom surface, the geometric center of the bottom surface is recessed into the light guide plate, and the geometric center and the bottom edges of the bottom surface form a cone, so that the bottom surface forms a plurality of slopes , which is characterized in that each slope forms a plurality of V-shaped protrusions parallel to the corresponding bottom, the V-shaped protrusions have the same shape, and the farther away from the bottom, the denser the arrangement density of the V-shaped protrusions, and the smaller the size big. 2. The light guide plate as claimed in claim 1, wherein the light emitting surface is a discharge fog surface. 3. The light guide plate according to claim 2, wherein the degree of fogging at the four corners of the light-emitting surface is greater than that at adjacent positions thereof. 4. The light guide plate according to claim 1, wherein the V-shaped protrusion has a first bottom angle adjacent to the corresponding bottom edge, a second bottom angle and a top angle, and the value range of the first bottom angle is is 5-60 degrees, the value range of the second base angle is 60-170 degrees, and the value range of the top angle is 60-170 degrees. 5. The light guide plate according to claim 1, wherein the distance between adjacent V-shaped protrusions ranges from 0.001 mm to 3.0 mm. 6 . The light guide plate according to claim 1 , wherein the height of the V-shaped protrusion ranges from 0.001 mm to 1.0 mm. 7. The light guide plate as claimed in claim 1, characterized in that the light guide plate is made of transparent resin material. 8. The light guide plate as claimed in claim 7, wherein the transparent resin material comprises acrylic resin, polycarbonate, polyethylene resin. 9. A backlight module, comprising: multiple light sources; A light guide plate, the light guide plate includes: As soon as the light comes out, a bottom surface opposite to the light-emitting surface, and The multiple light incident surfaces connecting the light emitting surface and the bottom surface, the multiple light sources are respectively close to the multiple light incident surfaces, the geometric center of the bottom surface is recessed into the light guide plate, and the geometric center and the multiple bottom surfaces of the bottom surface The edge forms a cone, so that the bottom surface forms a plurality of slopes, and it is characterized in that each slope forms a plurality of V-shaped protrusions parallel to the corresponding bottom edge, the V-shaped projections have the same shape, and the distance from the bottom edge is closer Far, the denser the arrangement density of the V-shaped protrusions is, the larger the size will be. 10. The backlight module according to claim 9, wherein the line light source comprises a linear cold cathode fluorescent lamp, an L-shaped cold cathode fluorescent lamp and a light emitting diode. 11. The backlight module according to claim 9, characterized in that the backlight module further comprises a reflector, the reflector is a frame structure surrounding the light guide plate and the plurality of line light sources, and it faces the A groove is formed inside the light incident surface of the light guide plate. 12. The backlight module as claimed in claim 11, wherein the reflector further comprises a total reflection film formed inside the groove.

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