Light guide plate, backlight module and display device

A light guide plate, a backlight module and a display device are provided. The light guide plate includes a main body, first stripe microstructures, second stripe microstructures and third stripe microstructures. The main body includes a light incidence surface and an optic surface having a first area and a second area. The first area is disposed nearer the light incidence surface. The first stripe microstructures and the second stripe microstructures are respectively disposed on the first area and the second area. Each of the first stripe microstructures and the second stripe microstructures extends along the direction vertical to the light incidence surface. A width of one end of each second stripe microstructure near the light incidence surface is smaller than a width of the other end away from the light incidence surface. The third stripe microstructures are distributed on a partial or the whole region of the optic surface.

BACKGROUND

Field of Invention

The present invention relates to a light guide element and its application. More particularly, the present invention relates to a light guide plate and its applications in a backlight module and a display device.

Description of Related Art

A conventional backlight module mainly includes a light bar and a light guide plate. The light bar includes a circuit board and plural light-emitting diodes disposed on a surface of the circuit board. The light guide plate is disposed adjacent to the light-emitting diodes, and a light-incident surface of the light guide plate contacts a light-emitting surface of each of the light-emitting diodes, thereby effectively improving light efficiency generated from the light-emitting diodes. However, because the light-incident surface of the light guide plate is connected to the light-emitting surface of each of the light-emitting diodes, a hotspots phenomenon or a non-uniform brightness phenomenon is likely to occur on a portion of the light guide plate adjacent to the light-emitting diodes, thus seriously affecting the optical appearance of the light guide plate.

On the other hand, in order to mix the light passing through the light guide plate uniformly, prism microstructures are generally disposed on the light-emitting surfaces of the light guide plate. However, such prism microstructures would result in the light guide plate with too much light concentration and too strong light directivity. Consequently, the light guide plate will have has obvious brightness and darkness, and bright and dark bands, fringes or hotspots are generated thereon.

SUMMARY

An object of the invention is to provide a light guide plate, a backlight module and a display device, in which the light guide plate has plural stripe microstructures, thereby solving the problem of the non-uniform brightness phenomenon generated on the light guide plate and increasing illumination uniformity of the backlight module and the display device.

According to the aforementioned object, a light guide plate is provided. The light guide plate includes a main body, plural first stripe microstructures, plural second stripe microstructures and plural third stripe microstructures. The main body includes a light incidence surface and an optic surface connected to the light incidence surface, in which the optic surface has a first area and a second area, and the first area is disposed nearer the light incidence surface than the second area. The first stripe microstructures are disposed on the first area of the optic surface, and each of the first stripe microstructures extends along a direction which is vertical to the light incidence surface. The second stripe microstructures are disposed on the second area of the optic surface, and each of the second stripe microstructures extends along the direction which is vertical to the light incidence surface, and a width of one end of each second stripe microstructure near the light incidence surface is smaller than a width of the other end of each second stripe microstructure away from the light incidence surface. The third stripe microstructures are distributed on a partial or the whole region of the optic surface which is not implemented with the first stripe microstructures and the second stripe microstructures.

According to an embodiment of the present invention, an inherent type of the first stripe microstructures is different from an inherent type of the second stripe microstructures.

According to an embodiment of the present invention, each of the third stripe microstructures extends along the direction which is vertical to the light incidence surface.

According to an embodiment of the present invention, the first area and the second area are arranged along the direction which is vertical to the light incidence surface.

According to an embodiment of the present invention, each of the second stripe microstructures is a convex structure, and a height of one end of each second stripe microstructure near the light incidence surface is smaller than a height of the other end of each second stripe microstructure away from the light incidence surface.

According to an embodiment of the present invention, each of the second stripe microstructures is a concave structure, and a depth of one end of each second stripe microstructure near the light incidence surface is smaller than a depth of the other end of each second stripe microstructure away from the light incidence surface.

According to an embodiment of the present invention, the main body further includes a tapered portion and a plate portion, and the light incidence surface is located at a side of the tapered portion, and the optic surface is located on the plate portion.

According to an embodiment of the present invention, the first stripe microstructures are continuously arranged side by side.

According to an embodiment of the present invention, each of the first stripe microstructures includes a strip portion and a tapered structure, and the tapered structure is connected to one end of the strip portion which is away from the light incidence surface, and a width of the tapered structure becomes gradually smaller from one end of the tapered structure near the light incidence surface to the other end of the tapered structure away from the light incidence surface.

According to an embodiment of the present invention, each of the second stripe microstructures comprises a strip portion and a tapered structure, in which the tapered structure is connected to one end of the strip portion which is near the light incidence surface, and a width of the tapered structure becomes gradually greater from one end of the tapered structure near the light incidence surface to the other end of the tapered structure away from the light incidence surface.

According to an embodiment of the present invention, a first contour line is defined by an end portion of each first stripe microstructure, and a second contour line is defined by an end portion of each second stripe microstructure. Therefore, a fan-shape area can be defined between the first contour line and the second contour line.

According to an embodiment of the present invention, the third stripe microstructures include plural first structure units. One end of each of the first structure units is connected to the first stripe microstructures, and the other end of each of the first structure units is connected to the second stripe microstructures.

According to an embodiment of the present invention, the third stripe microstructures include plural second structure units. One end of each of the second structure units is connected to the first stripe microstructures, and the other end of each of the second structure units is connected to a side edge of the optic surface which is away from the light incidence surface.

According to an embodiment of the present invention, the third stripe microstructures include plural third structure units. One end of each of the third structure units, and one end of each of the third structure units is connected to a first side edge of the optic surface which is near the light incidence surface, and the other end of each of the third structure units is connected to a second side edge of the optic surface which is away from the light incidence surface.

According to an embodiment of the present invention, the third stripe microstructures include plural fourth structure units. One end of each of the fourth structure units is connected to a side edge of the optic surface which is near the light incidence surface, and the other end of each of the fourth structure units is connected to the second stripe microstructures.

According to an embodiment of the present invention, the third stripe microstructures include plural fifth structure units. One end of each of the fifth structure units is located between a first side edge of the optic surface which is near the light incidence surface and a second side edge of the optic surface which is away from the light incidence surface, and the other end of each of the fifth structure units is connected to the second side edge.

According to an embodiment of the present invention, the third stripe microstructures include plural sixth structure units. One end of each of the sixth structure units is located between a first side edge of the optic surface which is near the light incidence surface and a second side edge of the optic surface which is away from the light incidence surface, and the other end of each of the sixth structure units is connected to the second stripe microstructures.

According to the aforementioned object, a backlight module is provided. The backlight module includes the aforementioned light guide plate and a light source. The light source disposed adjacent to the light incidence surface of the light guide plate.

According to the aforementioned object, a display device is provided. The display device includes the aforementioned light guide plate, a light source and a display panel. The light source is disposed adjacent to the light incidence surface of the light guide plate. The display panel is disposed in front of the light guide plate.

It can be known from the aforementioned embodiments of the present invention that, the light guide plate of the present invention has at least three different types of stripe microstructures disposed on the optic surface of the light guide plate, and the shapes, the heights, the depths, or the arrangement manners of the stripe microstructures can be varied to change the optical trends and the light-gathering capability of the light guide plate, thereby increasing light luminance value and luminance uniformity of the light guide plate.

DETAILED DESCRIPTION

Referring toFIG. 1andFIG. 2,FIG. 1andFIG. 2respectively illustrate a perspective view and a cross-sectional view of a backlight module400in accordance with a first embodiment of the present invention. The backlight module400of the present embodiment mainly includes a light guide plate500and a light source410. The light source410is disposed at a side of the light guide plate500. The light guide plate500mainly includes a main body510, plural first stripe microstructures520, plural second stripe microstructures530and plural third stripe microstructures540. The first stripe microstructures520, the second stripe microstructures530and the third stripe microstructures540are disposed on the main body510. The first stripe microstructures520are mainly used to mix light leaked from a portion near the light-incident side of the light guide plate500to improve a non-uniform brightness phenomenon near the light-incident side. The second stripe microstructures530are used to control optical trends of the light guide plate500, thereby solving the problem of bright bands generated on the light guide plate500. The third stripe microstructures540are used to increase light-emitting efficiency and uniformity of the overall light-emitting appearance of the light guide plate500. As shown inFIG. 1andFIG. 2, the main body510of the light guide plate500mainly includes a light incidence surface511and an optic surface512connected to the light incidence surface511. The optic surface512has a first area512aand a second area512b, in which the first area512ais disposed nearer the light incidence surface511than the second area512b. In the present embodiment, the first area512aand the second area512bare arranged along a direction D1, in which the direction D1is vertical to the light incidence surface511. As shown inFIG. 1andFIG. 2, the first stripe microstructures520are disposed in the first area512a, and each of the first stripe microstructures520extends along the direction D1. The second stripe microstructures530are disposed in the second area512b, and each of the stripe microstructures530also extends along the direction D1. In the present embodiment, an inherent type of the first stripe microstructures520is different from an inherent type of second stripe microstructures530. It is noted that, the “inherent type” used herein means the shapes or the arrangement densities of the first stripe microstructures520and the second stripe microstructures530.

Referring toFIG. 1andFIG. 2, each of the first stripe microstructures520includes a strip portion520aand a tapered structure520b. The tapered structure520bof each first stripe microstructure520is connected to an end of the strip portion520awhich is away from the light incidence surface511. A width of the tapered structure520bbecomes gradually smaller from one end of the tapered structure520bnear the light incidence surface511to the other end of the tapered structure520baway from the light incidence surface511. The strip portion520ahas a uniform width. On the other hand, each of the second stripe microstructures530is a tapered structure. A width of one end of each second stripe microstructure530near the light incidence surface511is smaller than a width of the other end of each second stripe microstructure530away from the light incidence surface511. Therefore, light leaked from a portion of the light guide plate500near the light incidence surface511can be mixed by the first stripe microstructures520. Moreover, light luminance of an area of the optic surface512near the light incidence surface511can be adjusted to be consistent with light luminance of an area of the optic surface512away from the light incidence surface511by the second stripe microstructures530.

Referring toFIG. 1andFIG. 2again, in the present embodiment, the third stripe microstructures540are distributed on the whole region of the optic surface512which is not implemented with the first stripe microstructures520and the second stripe microstructures530. Each of the third stripe microstructures540extends along the direction D1, thereby increasing the light-emitting efficiency and uniformity of the overall light-emitting appearance of the light guide plate500. In the present embodiment, the first stripe microstructures520are continuously arranged side by side, and the second stripe microstructures530are also continuously arranged side by side. The third stripe microstructures540include plural first structure units541. As shown inFIG. 1, one end of each first structure unit541is connected to the first stripe microstructures520, and the other end of each first structure unit541is connected to the second stripe microstructures530. In the present embodiment, the third stripe microstructures540are continuously arranged side by side, but not limited thereto. In other embodiments, the third stripe microstructures540can be discontinuously arranged.

In the present invention, the third stripe microstructures may have different designs according to the arrangement manners or the structural shapes of the first stripe microstructures and the second stripe microstructures. Referring toFIG. 3,FIG. 3illustrates a partial perspective view of a light guide plate600in accordance with a second embodiment of the present invention. The structure of the light guide plate600shown inFIG. 3is similar to that of the light guide plate500shown inFIG. 1, and the main difference therebetween is that second stripe microstructures603and third stripe microstructures604of the light guide plate600have different designs. As shown inFIG. 3, a portion of each second stripe microstructure603is a tapered structure, and the second stripe microstructures603are separated from each other by a distance. In addition, each of the second stripe microstructures603includes a strip portion603aand a tapered structure603b. The tapered structure603bis connected to one end of the strip portion603awhich is near the light incidence surface511. A width of the tapered structure603bbecomes gradually greater from one end of the tapered structure603bnear the light incidence surface511to the other end away from the light incidence surface511. The strip portion603ahas a uniform width.

Referring toFIG. 3again, in the present embodiment, the third stripe microstructures604includes plural first structure units604aand plural second structure units604b. One end of each first structure unit604ais connected to the first stripe microstructures520, and the other end of each first structure unit604ais connected to the second stripe microstructures603. One end of each second structure unit604bis connected to the first stripe microstructures520, and the other end of each second structure unit604bis connected to a side edge512cof the optic surface512which is away from the light incidence surface511. Therefore, the third stripe microstructures604can achieve the same object as the third stripe microstructures540, and therefore will not be described again herein. In the present embodiment, the third stripe microstructures604are continuously arranged side by side, but not limited thereto. In other embodiments, the third stripe microstructures604can be discontinuously arranged.

Referring toFIG. 4,FIG. 4illustrates a partial perspective view of a light guide plate610in accordance with a third embodiment of the present invention. The structure of the light guide plate610shown inFIG. 4is similar to that of the light guide plate500shown inFIG. 1andFIG. 2, and the main difference therebetween is that first stripe microstructures612, second stripe microstructures613and third stripe microstructures614of the light guide plate610have different designs. As shown inFIG. 4, the first stripe microstructures612on the light guide plate610are separated from each other by a distance, and the second stripe microstructures613are also separated from each other by a distance.

Referring toFIG. 4, in the present embodiment, the third stripe microstructures614include plural first structure units614a, plural third structure units614band plural fourth structure units614c. One end of each first structure unit614ais connected to the first stripe microstructures612, and the other end of each first structure unit614ais connected to the second stripe microstructures613. In addition, one end of each third structure unit614bis connected to a side edge512dof the optic surface512which is near the light incidence surface51, and the other end of each third structure unit614bis connected to the side edge512cof the optic surface512which is away from the light incidence surface511. Moreover, one end of each fourth structure unit614cis connected to the side edge512dof the optic surface512which is near the light incidence surface511, and the other end of each fourth structure unit614cis connected to the second stripe microstructures613. Therefore, third stripe microstructures614can achieve the same object as the third stripe microstructures540, and therefore will not be described again herein. In the present embodiment, the third stripe microstructures614are continuously arranged side by side, but not limited thereto. In other embodiments, the third stripe microstructures614can be discontinuously arranged.

It is noted that, in the aforementioned embodiments, distances between each second stripe microstructure and the light incidence surface are the same. In other embodiments, distances between each second stripe microstructure and the light incidence surface can be designed according to a radiation pattern generated by the light source. Referring toFIG. 5,FIG. 5illustrates a partial perspective view of a backlight module700in accordance with a fourth embodiment of the present invention. The backlight module700of the present embodiment mainly includes a light source710and a light guide plate720. The light source710is disposed at a light-incident side of the light guide plate720and includes a circuit board711and plural light-emitting diodes712disposed on the circuit board711. The structure of the light guide plate720shown in the present embodiment is similar to that of the light guide plate500shown inFIG. 1andFIG. 2, and the main difference therebetween is that second stripe microstructures723and third stripe microstructures724of the light guide plate720have different designs.

As shown inFIG. 5, the second stripe microstructures723are separated from each other by a distance. In addition, each of the second stripe microstructures723includes a strip portion723aand a tapered structure723b. The tapered structure723bis connected to an end of the strip portion723awhich is near the light incidence surface511. A width of the tapered structure723bbecomes gradually greater from one end of the tapered structure723bnear the light incidence surface511to the other end away from the light incidence surface511. The strip portion723ahas a uniform width. In the present embodiment, light emitted from each of the light-emitting diodes712is scattered into the light guide plate720, and a region of the light guide plate720which is in front of the light-emitting diodes712receives more light quantity than a region of the light guide plate720which is not in front of the light-emitting diodes712. Therefore, in the present embodiment, the distances between the light incidence surface511and the second stripe microstructures723located in front of the light-emitting diodes712are greater than the distances between the light incidence surface511and the second stripe microstructures723not located in front of the light-emitting diodes712, so that a fan-shape area is formed between the first stripe microstructures520and the second stripe microstructures723. In other words, the fan-shape area is formed between a first contour line A1and a second contour line A2, in which the first contour line A1is defined by an end portion of each first stripe microstructure520, and the second contour line A2is defined by an end portion of each second stripe microstructure723. Therefore, light quantity emitted from the second stripe microstructures723which are not located in front of the light-emitting diodes712is more efficiency than that emitted from the second stripe microstructures723which are located in front of the light-emitting diodes712, thereby uniforming light luminance of the light guide plate720.

Referring toFIG. 5again, in the present embodiment, the third stripe microstructures724include plural first structure units724aand plural second structure units724b. One end of each first structure unit724ais connected to the first stripe microstructures520, the other end of each first structure unit724ais connected to the second stripe microstructures723. One end of each second structure units724bis connected to the first stripe microstructures520, the other end of each second structure units724bis connected to the side edge512cof the optic surface512away from the light incidence surface511. Therefore, the third stripe microstructures724can achieve the same object as the third stripe microstructures540, and therefore will not be described again herein. In the present embodiment, the third stripe microstructures724are continuously arranged side by side, but not limited thereto. In other embodiments, the third stripe microstructures724can be discontinuously arranged.

It is noted that, it is not limited that the third stripe microstructures are distributed on the whole region of optic surface512which is not implemented with the first stripe microstructures and the second stripe microstructures. In other embodiments, the third stripe microstructures can be only distributed on a partial region of the optic surface which is not implemented with the first stripe microstructures and the second stripe microstructures. Referring toFIG. 6,FIG. 6illustrates a partial perspective view of a light guide plate800in accordance with a fifth embodiment of the present invention. The structure of the light guide plate800shown inFIG. 6is similar to that of the light guide plate600shown inFIG. 3, and the main difference therebetween is that third stripe microstructures704of the light guide plate800have different designs.

Referring toFIG. 6again, in the present embodiment, the third stripe microstructures704include plural fifth structure units704aand plural sixth structure units704b. One end of each fifth structure unit704ais located between the side edge512dof the optic surface512near the light incidence surface511and the side edge512cof the optic surface512away from the light incidence surface511, and the other end of each fifth structure unit704ais connected to the side edge512c. In other words, one end of each fifth structure unit704ais not connected to the side edge512dor the first stripe microstructures520, and the other each fifth structure unit704ais directly connected to the side edge512c. As shown inFIG. 6, one end of each sixth structure unit704bis located between the side edge512dof the optic surface512near the light incidence surface511and the side edge512cof the optic surface512away from the light incidence surface511, and the other end of each sixth structure unit704bis connected to the second stripe microstructures603. In other words, one end of each sixth structure unit704bis not connected to the side edge512dor the first stripe microstructures520, and the other end of each sixth structure unit704bis directly connected to the second stripe microstructures603. Therefore, the third stripe microstructures704can achieve the same object as the aforementioned third stripe microstructures604, and therefore will not be described again herein. In the present embodiment, the third stripe microstructures704are continuously arranged side by side, but not limited thereto. In other embodiments, the third stripe microstructures704can be discontinuously arranged.

It is noted that, the present invention is not limited to the aforementioned types of the third stripe microstructures and can be extended to any type of third stripe microstructures. In different embodiments, the third stripe microstructures may include the first structure units, second structure units, third structure units, fourth structure units, fifth structure units and sixth structure units, or any combination thereof, so as to meet different requirements. It is noted that, the terms “first”, “second”, “third”, “fourth”, “fifth” and “sixth” recited in the specification are merely used to name the elements and should not be regarded as the order or the number of the elements.

The main body of the light guide plate of the present invention may be a main body with a non-uniform thickness. Referring toFIG. 7,FIG. 7illustrates a partial perspective view of a light guide plate900in accordance with a sixth embodiment of the present invention. The structure of the light guide plate900of the present embodiment is similar to that of the light guide plate500shown inFIG. 1, and the main difference therebetween is that a main body910of the light guide plate900has different designs.

As shown inFIG. 7, the light guide plate900mainly includes a main body910, plural first stripe microstructures920, plural second stripe microstructures930and plural third stripe microstructures940. The first stripe microstructures920, second stripe microstructures930and third stripe microstructures940are disposed on the main body910. In the present embodiment, the main body910further includes a tapered portion910aand a plate portion910b. The main body910has a light incidence surface911and an optic surface912. The light incidence surface911is located at a side of the tapered portion910a, and the optic surface912is located on the plate portion910b. In addition, a thickness of one end of the tapered portion910anear the light incidence surface911is greater than a thickness of the other end of the tapered portion910aaway from the light incidence surface911. In the present embodiment, the first stripe microstructures920, the second stripe microstructures930and the third stripe microstructures940are disposed on the optic surface912. It is noted that, structures of the first stripe microstructures920, the second stripe microstructures930and the third stripe microstructures940are similar to those of the aforementioned first stripe microstructures520and612, the second stripe microstructures530,603,613and723, and the third stripe microstructures540,604,614,704and724, which will not be described again herein.

In the aforementioned embodiments, the second stripe microstructures530,603,613,723and930are convex structures, and a height of one end of each second stripe microstructures530,603,613,723and930near the light incidence surface511is smaller than a height of the other end away from the light incidence surface511. In other embodiments, each of the second stripe microstructures can be a concave structure, and a depth of one end of each second stripe microstructure near the light incidence surface is smaller than a depth of the other end of each second stripe microstructure away from the light incidence surface.

Referring toFIG. 8,FIG. 8illustrates a perspective view of a display device in accordance with an embodiment of the present invention. The display device1000includes the backlight module400as shown inFIG. 1andFIG. 2and a display panel1100. As shown inFIG. 8, the display panel1100is disposed in front of the light guide plate500of the backlight module400, so as to achieve the same objective as described above, and therefore will not be described again herein. It is noted that, the backlight module400shown inFIG. 26which has the light guide plate500is merely used as an example applied to the display device1000for explanation, and embodiments of the present invention are not limited thereto. In other embodiments, other light guide plates, such as the light guide plates500,600,610,720,800and900, of the aforementioned embodiments also can be applied to a display device, so as to achieve the same effect.

It can be known from the aforementioned embodiments of the present invention that, the light guide plate of the present invention has at least three different types of stripe microstructures disposed on the optic surface of the light guide plate, and the shapes, the heights, the depths, or the arrangement manners of the stripe microstructures can be varied to change the optical trends and the light-gathering capability of the light guide plate, thereby increasing light luminance value and luminance uniformity of the light guide plate.