Detailed Description
The foregoing and other technical and scientific aspects, features and utilities of the present invention will be apparent from the following detailed description of a preferred embodiment when read in conjunction with the accompanying drawings. Directional terms as referred to in the following examples, for example: up, down, left, right, front or rear, etc., are simply directions with reference to the drawings. Accordingly, the directional terminology is used for purposes of illustration and is in no way limiting.
Fig. 1A is a schematic top view of a light source module according to an embodiment of the invention. Fig. 1B is a cross-sectional view of the light source module of the embodiment of fig. 1A. Fig. 1C is a schematic cross-sectional view of a light guide plate of the light source module in the embodiment of fig. 1A. Please refer to fig. 1A and fig. 1B. FIG. 1B is a schematic view of the
light source module 10 of FIG. 1A
A schematic cross-section of a line. The
light source module 10 includes a
light guide plate 100 having a graded microstructure and a
light source 200. The
light guide plate 100 includes a
light emitting surface 110, a
bottom surface 120, a
light incident surface 130, and a plurality of
first microstructures 140. The
bottom surface 120 is opposite to the
light emitting surface 110. The
light incident surface 130 connects the
light emitting surface 110 and the
bottom surface 120. The
light guide plate 100 is made of a light-transmissive material such as polymethyl methacrylate (PMMA) or Polycarbonate (PC).
The light source 200 is used to provide a light beam I. In the present embodiment, the light source 200 is disposed beside the light incident surface 130 of the light guide plate 100, so that the light beam I can enter the light guide plate 100 from the light incident surface 130. In the present embodiment, the light source 200 may include a plurality of light emitting elements 210, and the light emitting elements 210 are arranged beside the light incident surface 130 along the second direction D2. The light emitting device 210 is, for example, but not limited to, a light emitting diode. In another embodiment, the light emitting elements 210 can be replaced by lamps. In order to clearly illustrate the structural features of the light source module, fig. 1A only illustrates the light guide plate 100 and the light source 200 of the light source module 10, and other elements are omitted.
The plurality of first microstructures 140 are disposed on the light emitting surface 110. Each of the plurality of first microstructures 140 extends along the first direction D1, and the plurality of first microstructures 140 are arranged along the second direction D2. The first direction D1 is parallel to the normal direction of the light incident surface 130, in other words, the first direction D1 is perpendicular to the light incident surface 130. The second direction D2 is perpendicular to the first direction D1. That is to say, the first microstructures 140 are disposed in a plurality of stripe structures on the light emitting surface 110 of the light guide plate 100, and the first microstructures 140 extend from the light incident surface 130 to a side surface (not labeled) opposite to the light incident surface 130, and are arranged on the light emitting surface 110 from one side edge of the light incident surface 130 to the other side edge of the light incident surface 130. In other embodiments, the light guide plate 100 further includes two opposite side surfaces (not shown), which are respectively connected to the light emitting surface 110, the bottom surface 120, the light incident surface 130, and the opposite side surfaces. The first microstructures 140 are arranged on the light emitting surface 110 from a side edge where the light emitting surface 110 is connected to one of the two side surfaces to a side edge where the light emitting surface 110 is connected to the other of the two side surfaces. In the present embodiment, the plurality of first microstructures 140 is integrally formed with the light guide plate 100.
Please refer to fig. 1A to fig. 1C. FIG. 1C is a schematic view of the
light guide plate 100 shown in FIG. 1A
A schematic cross-section of a line. As shown in fig. 1C, the plurality of
first microstructures 140 are disposed on the
light emitting surface 110 of the
light guide plate 100. In the present embodiment, the plurality of
first microstructures 140 includes a first microstructure
A first microstructure
A first microstructure
…, and a first microstructure
A first microstructure
…, etc. The invention is not limited to the number of first microstructures 140Therefore, a person skilled in the art can adjust the number of the
first microstructures 140 disposed on the
light guide plate 100 according to the design requirements of the actual product and referring to the teachings of the present embodiment. The
light guide plate 100 includes a
center 100M. The
center 100M of the light guide plate may be located at the center of the
light guide plate 100 in the second direction D2, or near the center of the
light guide plate 100 in the second direction D2. The light beam from the light source may enter the
light guide plate 100 along the first direction D1. In some embodiments, the plurality of
first microstructures 140 may be symmetrical to the
center 100M of the
light guide plate 100.
As shown in fig. 1C, each of the plurality of
first microstructures 140 has a triangular prism shape, for example. Each of the
first microstructures 140 has an inner angle α and an outer angle β with the
light emitting surface 110; in each of the
first microstructures 140, the inner included angle α is closer to the
center 100M of the
light guide plate 100 than the outer included angle β. As shown in fig. 1C, a first microstructure
With inner angle
And outside included angle
(ii) a First microstructure
With inner angle
And outside included angle
(ii) a And so on. In detail, each of the plurality of
first microstructures 140 has a
first microstructure surface 140S, and each of the plurality of
first microstructures 140S has an inner side (not labeled) and an outer side (not labeled) opposite to each other. First microstructure
The inner side and the outer side of the
first microstructure surface 140S may intersect with the
light emitting surface 110 of the
light guide plate 100 at an inner side X and an outer side Y, respectively, wherein the inner side X is closer to the
center 100M of the
light guide plate 100 than the outer side Y. First microstructure
The included angle between the tangent plane of the
first microstructure surface 140S at the inner side X and the
light emitting surface 110 is an inner side included angle
(ii) a First microstructure
The included angle between the tangent plane of the
first microstructure surface 140S at the outer side Y and the
light emitting surface 110 is an outer included angle
(ii) a And so on. In the present embodiment, the plurality of
first microstructures 140 further includes a first microstructure located at the
center 100M of the
light guide plate 100
Wherein the first microstructure is located at the
center 100M of the
light guide plate 100
The inner side surface and the outer side surface of the
first microstructure surface 140S may respectively form an included angle with the
light emitting surface 110 of the
light guide plate 100 at the same angle
That is to say the first microstructure
Is an isosceles triangle. In other embodiments, the first microstructures are located at the
center 100M of the
light guide plate 100 and located at two adjacent first microstructures
,
Adjacent to (3).
In the present embodiment, the included angle β between the outer sides of the
first microstructures 140 increases with distance from the
center 100M of the light guide plate. In other words, the first microstructure farther from the
center 100M
Outside included angle of
Is larger than the first microstructure
Outside included angle of
Angle of (2), first microstructure further from the
center 100M
Outside included angle of
Is larger than the first microstructure
Outside included angle of
The first microstructure further from the
center 100M
Outside included angle of
Is larger than the first microstructure
Outside included angle of
Angle of (2), first microstructure further from the
center 100M
Outside included angle of
Is larger than the first microstructure
Outside included angle of
In the same way, and so on. That is, as the distance between the
first microstructures 140 and the
center 100M of the light guide plate increases, the angle of the bottom angle of the
first microstructures 140 away from the center side increases. On the other hand, the angle of the inside included angle α of the plurality of
first microstructures 140 is a fixed value. In other words, the first microstructure
Inner side included angle of
A first microstructure
Inner side included angle of
.., and a first microstructure
Inner side included angle of
A first microstructure
Inner side included angle of
.., etc. are all the same. By the structural design of the plurality of
first microstructures 140, the angle and brightness of the light beam I emitted through the inner side of each
first microstructure 140 can be maintained, and the angle of the light beam I emitted through the outer side of each
first microstructure 140 can be changed, so that the light-emitting opening angles at different positions on the
light source module 10 can be controlled, the luminance of the
light source module 10 at two sides (for example, two opposite sides in the second direction D2) can be increased, the problem of dark bands at two sides of the
light source module 10 can be solved, and the overall uniformity of the picture can be improved. In addition, the embodiment of the invention can increase the luminance of the
light source module 10 at both sides, and still maintain the average luminance of the central region of the screen (e.g. relative to the middle portion of both sides in the second direction D2). Therefore, the average luminance of the whole screen area can be increased, and the efficiency of the
light source module 10 can be improved.
In another embodiment, the light guide plate 110 further includes blank regions (not shown) located at two ends of the light emitting surface in the second direction D2. The light-emitting surface 110 may have a blank region near the side edge connected to the two side surfaces, that is, the blank region does not have the first microstructures 140. Since the first microstructures 140 can increase the luminance of the light source module at two sides (e.g., two opposite sides in the second direction D2), when the light source module 10 further includes a plastic frame or a back plate surrounding the light guide plate 100, the plastic frame and the back plate can reflect the light emitted from the first microstructures 140 at the side edge portion where the light emitting surface 110 is connected to the two side surfaces toward the two sides of the light guide plate 100, so that the light source module 10 can generate edge bright lines at the two side portions of the light guide plate 100, thereby affecting the visual perception. Therefore, the brightness of the light guide plate 100 near the plastic frame or the back plate can be reduced through the white space on the light emitting surface 110 near the side edge connected to the two side surfaces, and the edge bright lines are avoided.
Please continue to refer to fig. 1C. In the present embodiment, a plurality of first microstructures140 have a width W along the second direction D2, the width W of the plurality of
first microstructures 140 decreasing away from the
center 100M of the
light guide plate 100. In the present embodiment, the first microstructure farther from the
center 100M
Width of (2)
Smaller than the first microstructure
Width of (2)
First microstructure further from the
center 100M
Width of (2)
Smaller than the first microstructure
Width of (2)
,., and so on. This feature of the
first microstructure 140 can help to improve the brightness of the light source module at both sides.
In addition, in some embodiments of the invention, each of the plurality of
first microstructures 140 has a height H relative to the
light emitting surface 110, and the height H of the plurality of
first microstructures 140 is a fixed value. In other words, the heights H of the plurality of
first microstructures 140 are substantially the same. In some embodiments, a plurality of first microstructures 140 (first microstructures)
A first microstructure
A first microstructure
…, and a first microstructure
A first microstructure
…, etc.) falls within the range of 0 millimeters to 0.2 millimeters.
In some embodiments of the present invention, the included angle α (e.g., included angle α) of the
first microstructures 140 is smaller than the included angle α of the first microstructures
Inner side included angle
.., and inner angle
Inner side included angle
.., etc.) and an outboard angle beta (e.g., an outboard angle
Outer side included angle
Outer side included angle
.., and outside angle
Outer side included angle
.., etc.) falls within the range of 0 degrees to 80 degrees. In some embodiments, the difference between the outer angles β of any two adjacent
first microstructures 140 in the plurality of
first microstructures 140 is in the range of 0 to 10 degrees. For example, adjacent first microstructures
And a first microstructure
Outside included angle
Angle with the outside
Falls within the range of 0 to 10 degrees. In some embodiments, the angle difference between the outer angles β of the adjacent
first microstructures 140 is constant, and the angles of the outer angles β of the plurality of
first microstructures 140 form an equal-difference sequence, wherein the first microstructures
Outside included angle of
According to the conditional formula:
where n is an integer and x can fall within the range of 0 to 10 degrees. However, in other embodiments, the angle difference between the outer angles β of the adjacent first microstructures 140 may not be constant, and the invention is not limited thereto.
As shown in fig. 1C, in the present embodiment, the plurality of first microstructures 140 are continuously disposed on the light emitting surface 110, that is, the interval between the plurality of first microstructures 140 in the second direction D2 is substantially 0. The length of each of the plurality of first microstructures 140 in the first direction D1 may fall within a range of 0 mm to 500 mm. In addition, the first microstructures 140 may be spaced apart from the light incident surface 130 in the first direction D1.
In the embodiment, each of the plurality of first microstructures 140 has a vertex angle (not labeled) far away from the light emitting surface 110, and the angle of the vertex angles decreases with the distance from the center 100M of the light guide plate 100. This feature of the first microstructure 140 can help to improve the brightness of the light source module 10 at both sides.
Please refer to fig. 1B. The light guide plate 100 may further include a plurality of second microstructures 150 disposed on the bottom surface 120. In the present embodiment, each of the second microstructures 150 is a concave structure. The second microstructure 150 may disrupt the total reflection of the light beam I. Therefore, the light beam I can exit from the light exit surface 110 and leave the light guide plate 100. That is, in the light source module 10 of the present embodiment, the second microstructures 150 can make the bottom surface 120 provide a diffusion effect to the light beam, so that the light beam I provided by the light source module 10 has better uniformity.
In addition, the light source module 10 may further include a reflective sheet 300. The reflective sheet 300 is disposed on the bottom surface 120 of the light guide plate 100. When the light beam I penetrates from the bottom surface 120 or the second microstructures 150 to leave the light guide plate 100, the reflective sheet 300 can reflect the light beam I back into the light guide plate 100, thereby increasing the light utilization efficiency of the light source module 10.
In addition, the light source module 10 may further include an optical film 400. The optical film 400 is disposed above the light emitting surface 110 of the light guide plate 100. The optical film 400 includes, for example, a prism sheet, a reverse prism sheet, a diffusion sheet, or a combination thereof, and different optical films can be selected according to different design requirements, which is not limited in the present invention. In the embodiment, the light beam emitted from the light emitting surface 110 passes through the optical film 400 and then exits from the light source module 10.
Fig. 2 is a schematic optical path diagram of a light guide plate according to an embodiment of the invention. The light guide plate 100 of fig. 2 may be similar to the light guide plate 100 of fig. 1A to 1C, but specific values, such as the number and size of the first microstructures 140, may be different.
Please refer to fig. 2. The light guide plate 100 may be divided into a central region CA and an edge region PA in the second direction D2, for example. The first microstructures 140 in the edge regions PA may have a larger included angle β than the central region CA. Therefore, when the light beam is emitted from the light emitting surface 110 of the light guide plate 100 through the first microstructure 140, the light emitting field angle of the edge area PA can be larger than that of the central area CA, so that the luminance of the edge area PA is improved, and the overall uniformity of the picture is improved.
In addition, because the first microstructures 140 in the central area CA and the edge area PA have fixed inner angles α, the brightness of the light emitted from the central area CA can be maintained, and the gradual change effect of the outer angle β can be prevented from being cancelled. Therefore, in the embodiment of the invention, while the light-emitting luminance of the light guide plate 100 in the edge area PA is improved, the light-emitting luminance of the central area CA can be maintained, so that the average luminance of the whole image can be improved. In the present embodiment, the inner angle α of the first microstructures 140 is a fixed value. Compared with the present embodiment, in the comparative example where the inner side included angles α of the plurality of first microstructures 140 are different, the light emitted from the first microstructures 140 in the central area CA may be non-uniform, and the light emitted from the portion of the first microstructures 140 close to the inner side included angle α may interfere with the light emitted from the portion of the first microstructures 140 close to the outer side included angle β, so that the luminance of the central area CA may be reduced, or the effect of improving the luminance of the light emitted from the edge area PA by the gradual change design that the outer side included angle β is reduced may be achieved.
Fig. 3A to 3C are schematic views of first microstructures of a light guide plate according to different embodiments of the invention. Please refer to fig. 3A to fig. 3C. The first microstructures 140 of the embodiment of fig. 3A are similar to the first microstructures 140 of the light guide plate 100 of fig. 1C. In the present embodiment, the plurality of first microstructures 140 are triangular prism-shaped structures. As shown in fig. 3A, the first microstructure 140 may have an inner angle α and an outer angle β.
The first microstructures 140a of the embodiment of fig. 3B are similar to the first microstructures 140 of fig. 3A, except that in the embodiment, the first microstructures 140a are free-form surface columnar structures. The free-form surface columnar structure can be a spherical columnar structure with a cross section outline of a conical curve, an aspheric columnar structure, or any free-form surface columnar structure with a cross section outline of a non-conical curve. As shown in fig. 3B, the first microstructure 140a may have an inner angle α and an outer angle β.
The first microstructures 140b of the embodiment of fig. 3C are similar to the first microstructures 140 of fig. 3A, but in this embodiment, the first microstructures 140b are pillar-shaped structures with flat tops. The first microstructure 140b may be similar to the first microstructure 140 or the columnar structure of the first microstructure 140a, but has a flat surface PS at the top portion thereof, which is substantially parallel to the light emitting surface 110 of the light guide plate. As shown in fig. 3C, the first microstructure 140b may have an inner angle α and an outer angle β.
Fig. 4 is a schematic cross-sectional view of a light guide plate of a light source module according to another embodiment of the invention. Please refer to fig. 4. The light guide plate 100a of the embodiment of fig. 4 is similar to the light guide plate 100 of fig. 1C, and the differences are as follows. The light guide plate 100a includes a plurality of first microstructures 140c, and the plurality of first microstructures 140c are disposed on the light emitting surface 110. The first microstructures 140C of the present embodiment are similar to the first microstructures 140C shown in fig. 1C, and the difference is that each of the first microstructures 140C has an inner side surface 140SA and an outer side surface 140SB opposite to each other, an inner side included angle α is formed between the inner side surface 140SA and the light emitting surface 110, an outer side included angle β is formed between the outer side surface 140SB and the light emitting surface 110, and the outer side surface 140SB includes two first surfaces 140SB1 arranged in parallel and a second surface 140SB2 arranged between the two first surfaces 140SB1 and vertically connecting the two first surfaces 140SB 1. It is known that when the light beam incident from a lower large angle enters the outer side surface 140SB, the light beam is refracted and then guided to exit in the forward direction of the light exit surface 110 of the light guide plate 100, and the light beam cannot exit in the side direction to overcome the side dark band problem. In the embodiment, for the light (for example, the light beam I1 in fig. 4) incident on the outer side surface 140SB of the first microstructure 140c at a relatively large angle from the lower side of the plurality of first microstructures 140c, the second surface 140SB2 can deflect part of the light from the lower side to the side direction for emitting, so that the problem that the light incident from the lower side at a large angle cannot be effectively guided to the two sides of the light guide plate 100 for emitting and still has dark side bands can be overcome, but the invention is not limited thereto.
Fig. 5 is a schematic cross-sectional view of a light guide plate of a light source module according to another embodiment of the invention. Please refer to fig. 5. The light guide plate 100b of the embodiment of fig. 5 is similar to the light guide plate 100 of fig. 1C, and the differences are as follows. The light guide plate 100b includes a plurality of first microstructures 140 d. The plurality of first microstructures 140d are disposed on the light emitting surface 110. The first microstructures 140d of the present embodiment are similar to the first microstructures 140 shown in fig. 1C, and the difference is that each of the first microstructures 140d has an inner side surface 140SA and an outer side surface 140SB opposite to each other, an inner side included angle α is formed between the inner side surface 140SA and the light emitting surface 110, an outer side included angle β is formed between the outer side surface 140SB and the light emitting surface 110, the inner side surface 140SA is a first curved surface C1, and the curvatures of the first curved surfaces C1 of the first microstructures 140d are all the same. In the embodiment, the inner side surface 140SA with a curved surface configuration is adopted to increase the forward emitting effect of the light, but the invention is not limited thereto.
Fig. 6 is a schematic cross-sectional view of a light guide plate of a light source module according to still another embodiment of the invention. Please refer to fig. 6. The light guide plate 100C of the embodiment of fig. 6 is similar to the light guide plate 100 of fig. 1C, and the differences are as follows. The light guide plate 100c includes a plurality of first microstructures 140 e. The first microstructures 140e are disposed on the light emitting surface 110. The first microstructures 140e of the present embodiment are similar to the first microstructures 140 shown in fig. 1C, and the difference is that each of the first microstructures 140e has an inner side surface 140SA and an outer side surface 140SB opposite to each other, an inner side included angle α is formed between the inner side surface 140SA and the light emitting surface 110, an outer side included angle β is formed between the outer side surface 140SB and the light emitting surface 110, the inner side surface 140SA is a first curved surface C1, and the curvatures of the first curved surfaces C1 of the first microstructures 140e are all the same. And the outer side 140SB is the second curved surface C2, the curvature of the second curved surface C2 of the first microstructure 140e increases with distance from the center 100M of the light guide plate 100C. In the embodiment, for the light rays from the lower portions of the plurality of first microstructures 140e that are incident on the outer side 140SB of the first microstructures 140e at relatively large angles, the outer side 140SB of the first microstructures 140e can effectively guide the light rays to exit laterally, so as to improve the problem of side dark bands.
In summary, the light source module or the light guide plate of the invention can increase the brightness of the light source module at both sides by the structural design of the inner included angles and the outer included angles of the plurality of first microstructures, thereby improving the problem of dark bands at both sides of the light source module and improving the overall uniformity of the picture. In addition, the embodiment of the invention can maintain the average brightness of the central area of the picture while increasing the brightness of the light source module at two sides. Therefore, the average brightness of the whole picture area can be increased, and the efficiency of the light source module can be improved.
The above description is only a preferred embodiment of the present invention, and the scope of the present invention should not be limited thereby, and all the simple equivalent changes and modifications made according to the claims and the content of the specification should be included in the scope of the present invention. It is not necessary for any embodiment or claim of the invention to achieve all of the objects or advantages or features disclosed herein. Furthermore, the abstract and the title of the specification are provided only for assisting the retrieval of patent documents and are not intended to limit the scope of the present invention. Furthermore, the terms "first", "second", and the like in the description or the claims are used only for naming elements (elements) or distinguishing different embodiments or ranges, and are not used for limiting the upper limit or the lower limit on the number of elements.