TWI842546B - Light source module - Google Patents

Abstract

A light source module including a light guide plate and a light source is provided. The light guide plate has a light incident surface and a light exit surface connected to each other. The light source is disposed on a side of the light incident surface of the light guide plate. The light guide plate comprises a substrate and a first optical microstructure and a second optical microstructure embedded in the substrate and overlapped with each other along the normal direction of the light exit surface. The refractive index of each of the first optical microstructure and the second optical microstructure is different from the refractive index of the substrate. The first optical microstructure has a first bottom surface and a first vertex angle away from each other. The second optical microstructure has a second bottom surface and a second vertex angle away from each other. The first bottom surface of the first optical microstructure is away from the second bottom surface of the second optical microstructure. The first vertex angle of the first optical microstructure faces the second vertex angle of the second optical microstructure. The first vertex angle and the second vertex angle are within a range of 120 degrees to 145 degrees.

Description

Light source module

The present invention relates to a light source module, and in particular to a light source module with a highly collimated light guide plate.

The demand for anti-obstruction display and high brightness display has driven the development of high-collimation light guide plates. Generally speaking, in addition to the dot design, high-collimation light guide plates are also equipped with reverse prisms with a top angle of less than 70 degrees to guide the light to the required angle. This feature can also be applied to fully reflective display panels. Since it is used as a front light source, the dots of the light guide plate cannot be set on the bonding surface with the fully reflective display panel, but must be set on the exterior surface instead. In order to prevent the dots from being scratched and unable to produce a refractive effect, an additional cover plate must be set on the exterior side for protection, which will inevitably increase the overall thickness of the fully reflective display device.

The present invention provides a light source module which has better light collimation and is suitable for thin and light display devices.

The light source module of the present invention comprises a light guide plate and a light source. The light guide plate has a light incident surface and a light emitting surface connected to the light incident surface. The light source is arranged on one side of the light incident surface of the light guide plate. The light guide plate comprises a substrate, a first optical microstructure and a second optical microstructure. The substrate is provided with a light emitting surface and a light incident surface. The first optical microstructure and the second optical microstructure are embedded in the substrate and overlap each other along the normal direction of the light emitting surface. The refractive index of each of the first optical microstructure and the second optical microstructure is different from the refractive index of the substrate. The first optical microstructure has a first bottom surface and a first top angle away from the first bottom surface. The second optical microstructure has a second bottom surface and a second top angle away from the second bottom surface. The first bottom surface of the first optical microstructure and the second bottom surface of the second optical microstructure are opposite to each other. The first top angle of the first optical microstructure and the second top angle of the second optical microstructure face each other. The first vertex angle and the second vertex angle are each within the range of 120 degrees to 145 degrees.

In an embodiment of the present invention, the first optical microstructure of the light source module further comprises a first inclined plane, a first curved plane and a second inclined plane. The first curved plane connects the first inclined plane and the second inclined plane. The second curved plane is located between the first curved plane and the light incident surface. The first inclined plane and the second inclined plane define a first vertex angle. The second optical microstructure further comprises a third inclined plane, a second curved plane and a fourth inclined plane. The second curved plane connects the third inclined plane and the fourth inclined plane. The third curved plane is located between the second curved plane and the light incident surface. The third inclined plane and the fourth inclined plane define a second vertex angle. The first curved plane of the first optical microstructure overlaps the fourth inclined plane of the second optical microstructure along the normal direction of the light exit surface of the light guide plate, and the second curved plane of the second optical microstructure overlaps the second inclined plane of the first optical microstructure along the normal direction of the light exit surface of the light guide plate.

In one embodiment of the present invention, the angle between the first inclined surface and the first bottom surface of the first optical microstructure of the light source module and the angle between the third inclined surface and the second bottom surface of the second optical microstructure are in the range of 20 degrees to 45 degrees.

In one embodiment of the present invention, the angle between the second inclined surface of the first optical microstructure of the light source module and the first bottom surface and the angle between the fourth inclined surface of the second optical microstructure and the second bottom surface are in the range of 15 degrees to 25 degrees.

In one embodiment of the present invention, the first optical microstructure of the light source module further has a fifth inclined surface connected to the second inclined surface. The second optical microstructure further has a sixth inclined surface connected to the fourth inclined surface. The angle between the fifth inclined surface of the first optical microstructure and the first bottom surface and the angle between the sixth inclined surface of the second optical microstructure and the second bottom surface are in the range of 28 degrees to 38 degrees.

In one embodiment of the present invention, the light guide plate of the light source module further has a surface connected to the light receiving surface and facing away from the light emitting surface. A gap is provided between the first curved surface of the first optical microstructure and the second curved surface of the second optical microstructure. The light guide plate has a thickness along the normal direction of the light emitting surface. The geometric center of the gap has a distance from the light emitting surface or the surface along the normal direction of the light emitting surface, and the ratio of the distance to the thickness is in the range of 0.25 to 0.5.

In one embodiment of the present invention, the ratio of the distance between the geometric center of the gap of the light source module and the light emitting surface along the normal direction of the light emitting surface to the thickness is in the range of 0.25 to 0.5, and the first optical microstructure is located between the second optical microstructure and the light emitting surface.

In one embodiment of the present invention, the ratio of the distance between the geometric center of the gap of the light source module and the surface of the light guide plate along the normal direction of the light emitting surface to the thickness is in the range of 0.25 to 0.5, and the first optical microstructure is located between the second optical microstructure and the surface of the light guide plate.

In one embodiment of the present invention, the refractive index of the substrate of the light source module is in the range of 1.4 to 1.65, and the refractive index of the first optical microstructure and the second optical microstructure is in the range of 1.69 to 1.81.

In one embodiment of the present invention, the light guide plate of the light source module further has a surface connected to the light receiving surface and away from the light emitting surface, and the surface is provided with a texture structure. The texture structure includes a plurality of first micro-protrusions and a plurality of second micro-protrusions. These first micro-protrusions extend in a first direction. These second micro-protrusions extend in a second direction. The second direction intersects with the first direction. These first micro-protrusions and these second micro-protrusions are arranged alternately along the first direction and the second direction, respectively. Each first micro-protrusion has a first height along the normal direction of the light emitting surface. Each second micro-protrusion has a second height along the normal direction of the light emitting surface. The first height is different from the second height.

In one embodiment of the present invention, the first direction of the light source module is parallel to the light incident surface. The second direction is perpendicular to the light incident surface, and the ratio of the first height of each first micro-protrusion to the second height of each second micro-protrusion is in the range of 1.5 to 2.5.

In one embodiment of the present invention, an air gap is provided between the first optical microstructure and the second optical microstructure of the light source module.

Based on the above, in a light source module of an embodiment of the present invention, a first optical microstructure and a second optical microstructure are embedded in the light guide plate. The two optical microstructures have two top angles facing each other and between 120 and 145 degrees and two bottom surfaces facing each other. In this way, in addition to preventing the optical microstructure from being exposed on the surface of the light guide plate and being unusable due to scratches, the demand for highly collimated light can also be met.

1: Display device

100, 100A, 100B: Light guide plate

100es: bright surface

100is: light-entering surface

100s, 111s, 112s: surface

110, 110A: Substrate

111, 112, 111A, 112A: base material

115: Adhesive layer

120: Light source

210: Pixel array substrate

220: Color filter substrate

230:Drive circuit board

AD: Adhesive layer

AG: Air gap

A1-1, A1-2, A2-1, A2-2, A3-1, A3-2: Angle

BS1: First bottom surface

BS2: Second bottom surface

CS1: First curved surface

CS2: Second curved surface

CV: Chamber

d, d”: distance

DP: Display Panel

DS: Display Surface

G: Gap

GC: Geometry Center

H1: First height

H2: Second height

IP1: First slope

IP2: Second slope

IP3: Third slope

IP4: Fourth slope

IP5: Fifth slope

IP6: Sixth slope

LB: Light

LSM, LSM-A, LSM-B: Light source module

MP1: First micro protrusion

MP2: Second micro protrusion

MS1, MS1-A: The first optical microstructure

MS2, MS2-A: Second optical microstructure

T, t1, t2, t1”, t2”: thickness

TS, TS”: Texture structure

VA1: First vertex

VA2: Second top angle

X, Y, Z: direction

I-I’: section line

FIG1 is a schematic cross-sectional view of a display device according to the first embodiment of the present invention.

Figure 2 is a schematic cross-sectional view of the light source module of Figure 1.

FIG3 is an enlarged cross-sectional view of a local area of the light guide plate of FIG2.

Figure 4 is a three-dimensional schematic diagram of the first optical microstructure and the second optical microstructure of Figure 3.

Figures 5A to 5C are cross-sectional schematic diagrams of the manufacturing process of the light guide plate of Figure 2.

FIG6A is a top view schematic diagram of the texture structure provided on the surface of the light guide plate of FIG2 away from the light emitting surface.

FIG6B is a schematic top view of a texture structure according to another variant embodiment of the present invention.

FIG7 is a schematic cross-sectional view of the texture structure of FIG6A.

Figure 8A and Figure 8B are three-dimensional schematic diagrams of the first optical microstructure and the second optical microstructure according to the second embodiment of the present invention.

FIG9 is a schematic cross-sectional view of a light source module according to the third embodiment of the present invention.

FIG10 is a schematic cross-sectional view of a light source module according to the fourth embodiment of the present invention.

The above-mentioned other technical contents, features and effects of the present invention will be clearly presented in the detailed description of the preferred embodiment with reference to the following drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only referenced to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and are not used to limit the present invention.

FIG1 is a schematic cross-sectional view of a display device according to a first embodiment of the present invention. FIG2 is a schematic cross-sectional view of a light source module of FIG1. FIG3 is an enlarged cross-sectional view of a local area of a light guide plate of FIG2. FIG4 is a three-dimensional schematic view of a first optical microstructure and a second optical microstructure of FIG3. FIG5A to FIG5C are schematic cross-sectional views of a manufacturing process of a light guide plate of FIG2. FIG6A is a schematic top view of a texture structure provided on a surface of the light guide plate of FIG2 away from a light emitting surface. FIG6B is a schematic top view of a texture structure according to another variant embodiment of the present invention. FIG7 is a schematic cross-sectional view of a texture structure of FIG6A. FIG7 corresponds to section line I-I' of FIG6A.

Referring to FIG. 1 , the display device 1 includes a display panel DP and a light source module LSM. In the present embodiment, the display panel DP is, for example, a reflective liquid crystal display panel and has a display surface DS. The light source module LSM is disposed on one side of the display surface DS of the display panel DP, that is, the light source module LSM can be used as a front light source of the display panel DP. In the present embodiment, the display panel DP may include a pixel array substrate 210, a color filter substrate 220, a liquid crystal layer (not shown) sandwiched between the pixel array substrate 210 and the color filter substrate 220, and a driving circuit board 230 bonded to the pixel array substrate 210, but is not limited thereto.

For example, the pixel array substrate 210 may be provided with a plurality of pixel structures (not shown), a plurality of signal traces electrically connected to the pixel structures (such as data lines or scan lines, not shown), and a driving circuit electrically connected to the signal traces (such as a source driving circuit or a gate driving circuit, not shown). The color filter substrate 220, for example, includes a plurality of color filter patterns (not shown) corresponding to the aforementioned plurality of pixel structures. These color filter patterns are respectively suitable for allowing light of different colors (such as red, green and blue, but not limited thereto) to pass through, so as to achieve a color display effect.

On the other hand, the light source module LSM includes a light guide plate 100 and a light source 120. The light guide plate 100 has a light incident surface 100is and a light emitting surface 100es and a surface 100s connected to the light incident surface 100is and facing each other. The light source 120 is disposed on one side of the light incident surface 100is of the light guide plate 100. The light emitting surface 100es of the light guide plate 100 faces the display surface DS of the display panel DP. For example, in this embodiment, the light guide plate 100 can be attached to the color filter substrate 220 of the display panel DP by an adhesive layer AD, wherein the adhesive layer AD can be a pressure sensitive adhesive (PSA), an optical clear resin (OCR) optical adhesive or a liquid optically clear adhesive (LOCA), but is not limited thereto.

Referring to FIG. 2 and FIG. 3 , the light guide plate 100 includes a substrate 110, a plurality of first optical microstructures MS1, and a plurality of second optical microstructures MS2. It is particularly noted that the first optical microstructures MS1 and the second optical microstructures MS2 are embedded in the substrate 110 and overlap each other along the normal direction (e.g., direction Z) of the light emitting surface 100es. More specifically, the first optical microstructures MS1 and the second optical microstructures MS2 are disposed in the substrate 110 and are spaced between the light emitting surface 100es and the surface 100s.

In detail, the substrate 110 of the light guide plate 100 may include a substrate 111 and a substrate 112. The first optical microstructure MS1 is disposed on a surface 111s of the substrate 111 facing the substrate 112. The second optical microstructure MS2 is disposed on a surface 112s of the substrate 112 facing the substrate 111. The first optical microstructure MS1 has a first bottom surface BS1 in contact with the surface 111s of the substrate 111 and a first top angle VA1 away from the first bottom surface BS1. The second optical microstructure MS2 has a second bottom surface BS2 in contact with the surface 112s of the substrate 112 and a second top angle VA2 away from the second bottom surface BS2. More specifically, the first bottom surface BS1 of the first optical microstructure MS1 and the second bottom surface BS2 of the second optical microstructure MS2 are opposite to each other, and the first top angle VA1 of the first optical microstructure MS1 and the second top angle VA2 of the second optical microstructure MS2 are facing each other.

Preferably, the first vertex angle VA1 of the first optical microstructure MS1 and the second vertex angle VA2 of the second optical microstructure MS2 may each be in the range of 120 degrees to 145 degrees. In this embodiment, the first vertex angle VA1 and the second vertex angle VA2 may be selectively the same, but are not limited thereto. In other embodiments, the first vertex angle VA1 of the first optical microstructure MS1 may be different from the second vertex angle VA2 of the second optical microstructure MS2.

From another point of view, the first optical microstructure MS1 has a first bevel IP1, a second bevel IP2 and a first curved surface CS1. The first curved surface CS1 connects the first bevel IP1 and the second bevel IP2. The second bevel IP2 is located between the first curved surface CS1 and the light incident surface 100is. The first bevel IP1 and the second bevel IP2 can define a first vertex angle VA1. Similarly, the second optical microstructure MS2 has a third bevel IP3, a second curved surface CS2 and a fourth bevel IP4. The second curved surface CS2 connects the third bevel IP3 and the fourth bevel IP4. The third bevel IP3 is located between the second curved surface CS2 and the light incident surface 100is. The third bevel IP3 and the fourth bevel IP4 can define a second vertex angle VA2.

Preferably, the angle A1-1 between the first inclined surface IP1 of the first optical microstructure MS1 and the first bottom surface BS1 and the angle A1-2 between the third inclined surface IP3 of the second optical microstructure MS2 and the second bottom surface BS2 may be in the range of 20 degrees to 45 degrees. The angle A2-1 between the second inclined surface IP2 of the first optical microstructure MS1 and the first bottom surface BS1 and the angle A2-2 between the fourth inclined surface IP4 of the second optical microstructure MS2 and the second bottom surface BS2 may be in the range of 15 degrees to 25 degrees.

In this embodiment, the first optical microstructure MS1 further has a fifth inclined surface IP5 connected to the second inclined surface IP2, and the second optical microstructure MS2 further has a sixth inclined surface IP6 connected to the fourth inclined surface IP4. Preferably, the angle A3-1 between the fifth inclined surface IP5 of the first optical microstructure MS1 and the first bottom surface BS1 and the angle A3-2 between the sixth inclined surface IP6 of the second optical microstructure MS2 and the second bottom surface BS2 may be in the range of 28 degrees to 38 degrees. That is, a fold angle is formed between the second inclined surface IP2 and the fifth inclined surface IP5 of the first optical microstructure MS1, and a fold angle is formed between the fourth inclined surface IP4 and the sixth inclined surface IP6 of the second optical microstructure MS2.

In this embodiment, the first optical microstructure MS1 and the second optical microstructure MS2 may be of a semi-spun hammer-like shape (as shown in FIG. 4 ), but the present invention is not limited thereto.

It should be noted that, although the first optical microstructure MS1 and the second optical microstructure MS2 overlap each other along the normal direction (e.g., direction Z) of the light emitting surface 100es, the first curved surface CS1 of the first optical microstructure MS1 does not overlap the second curved surface CS2 of the second optical microstructure MS2. More specifically, the first curved surface CS1 of the first optical microstructure MS1 overlaps the fourth inclined surface IP4 of the second optical microstructure MS2 along the normal direction of the light emitting surface 100es of the light guide plate 100, and the second curved surface CS2 of the second optical microstructure MS2 overlaps the second inclined surface IP2 of the first optical microstructure MS1 along the normal direction of the light emitting surface 100es of the light guide plate 100.

After the light LB from the light source 120 and transmitted in the substrate 110 enters the second optical microstructure MS2, it will leave the second optical microstructure MS2 through the refraction of the fourth inclined surface IP4, and enter the first optical microstructure MS1 through the refraction of the first curved surface CS1. Through the matching design of the inclined surfaces and curved surfaces of the two overlapping optical microstructures, the light LB can be effectively directed to the required light output angle to avoid a large amount of light energy loss, thereby greatly improving the lighting efficiency of the light source module LSM for the display panel.

In the present embodiment, an adhesive layer 115 is filled between the first optical microstructures MS1 and the second optical microstructures MS2, and the refractive index of each of the first optical microstructures MS1 and the second optical microstructures MS2 is different from the refractive index of each of the substrate 110 and the adhesive layer 115. Preferably, the refractive index of each of the first optical microstructures MS1 and the second optical microstructures MS2 may be in the range of 1.69 to 1.81, and the refractive index of each of the substrate 110 and the adhesive layer 115 may be in the range of 1.4 to 1.65. For example, the refractive index of the first optical microstructures MS1 and the second optical microstructures MS2 may be the same and, for example, 1.7, and the refractive index of the substrate 110 and the adhesive layer 115 may be the same and, for example, 1.56, but the present invention is not limited thereto. In other embodiments, the refractive index of the adhesive layer 115 may be different from the refractive index of the substrate 110, or the refractive index of the first optical microstructure MS1 may be different from the refractive index of the second optical microstructure MS2.

A gap G is provided between the first curved surface CS1 of the first optical microstructure MS1 and the second curved surface CS2 of the second optical microstructure MS2. The light guide plate 100 has a thickness T along the normal direction of the light emitting surface 100es, and the geometric center GC of the gap G has a distance d from the light emitting surface 100es along the normal direction of the light emitting surface, and the ratio of the distance d to the thickness T is 0.25. That is, in this embodiment, the first optical microstructure MS1 and the second optical microstructure MS2 are arranged on a side closer to the light emitting surface 100es of the light guide plate 100, and the first optical microstructure MS1 is located between the second optical microstructure MS2 and the light emitting surface 100es, but is not limited thereto.

In another embodiment not shown, the ratio of the distance between the geometric center of the gap between the two curved surfaces of the two optical microstructures and the light emitting surface of the light guide plate to the thickness of the light guide plate may also be greater than 0.25 and less than or equal to 0.5. That is, the ratio may be in the range of 0.25 to 0.5.

The following is an exemplary description of the manufacturing process of the light guide plate 100 of this embodiment.

First, a plurality of first optical microstructures MS1 are formed on the surface 111s of the substrate 111, and a plurality of second optical microstructures MS2 are formed on the surface 112s of another substrate 112, as shown in FIG. 5A and FIG. 5B. It is particularly noted that in this embodiment, the thickness t1 of the substrate 111 may be significantly smaller than the thickness t2 of the substrate 112.

Please refer to FIG. 5C. Next, the surface 112s of the substrate 112 is placed facing the surface 111s of the substrate 111, so that the plurality of second optical microstructures MS2 and the plurality of first optical microstructures MS1 are arranged opposite to each other, and the substrates 111 and 112 are assembled. For example, but not limited to this, before assembly, the first optical microstructures MS1 on the substrate 111 or the second optical microstructures MS2 on the substrate 112 may be coated with a layer of adhesive. After assembly, the adhesive filled between the first optical microstructures MS1 and the second optical microstructures MS2 may be subjected to a light or heat curing process to form an adhesive layer 115 that joins the two substrates, as shown in FIG. 2. At this point, the manufacture of the light guide plate 100 of this embodiment is completed.

From another point of view, the first optical microstructure MS1 and the second optical microstructure MS2 of the assembled light guide plate 100 are covered by the substrate 110 and the adhesive layer 115 formed by the substrate 111 and the substrate 112. In other words, these optical microstructures are not exposed on the light emitting surface 100es or the surface 100s of the light guide plate 100, so these optical microstructures can be prevented from being scratched and unusable, which greatly increases the durability of the light guide plate 100. In addition, since the optical microstructure of this embodiment is embedded in the substrate 110, the application scope and design flexibility of the light source module LSM are greatly increased.

For example, the light source module LSM of this embodiment can also be used as a backlight module of a transmissive liquid crystal display panel. That is, the light source module LSM can be arranged on the side of the transmissive liquid crystal display panel away from the display surface, and the light emitting surface of the light guide plate can be defined by the aforementioned light emitting surface 100es or surface 100s, and it is not necessary to consider the matching relationship between the light guide plate and the display panel or the optical film when the surface of the light guide plate is provided with an optical microstructure.

Furthermore, in order to allow the display device 1 of FIG. 1 to have a paper-like effect on the surface 100s of the light guide plate 100 of the light source module LSM (for example, to achieve a visual effect and touch similar to that of cardboard), the surface 100s of the light guide plate 100 may be provided with a texture structure TS, as shown in FIG. 6A. For example, the texture structure TS may include a plurality of first micro-protrusions MP1 extending in a direction X and a plurality of second micro-protrusions MP2 extending in a direction Y, wherein the direction X may be selectively perpendicular to the direction Y, but is not limited thereto.

In this embodiment, a plurality of first micro-protrusions MP1 and a plurality of second micro-protrusions MP2 may be arranged alternately along directions X and Y, respectively, to form a texture structure TS in a plain pattern. However, the present invention is not limited thereto. Referring to FIG. 6B , in another variant embodiment, a plurality of first micro-protrusions MP1 and a plurality of second micro-protrusions MP2 may also be arranged in different ways along directions X and Y, respectively, for example: two second micro-protrusions MP2 and one first micro-protrusion MP1 are arranged alternately along direction X, and two first micro-protrusions MP1 and one second micro-protrusion MP2 are arranged alternately along direction Y, to form a texture structure TS in a twill pattern."

Please refer to FIG. 6A . In this embodiment, the extension direction of the first micro-protrusion MP1 may be selectively parallel to the light incident surface 100is of the light guide plate 100, and the extension direction of the second micro-protrusion MP2 may be selectively perpendicular to the light incident surface 100is of the light guide plate 100, but it is not limited thereto. Please refer to FIG. 7 . The first micro-protrusion MP1 and the second micro-protrusion MP2 have a first height H1 and a second height H2 respectively along the normal direction (e.g., direction Z) of the surface 100s, and the first height H1 is different from the second height H2.

In this embodiment, the first height H1 of the first micro protrusion MP1 may be greater than the second height H2 of the second micro protrusion MP2, and the ratio of the first height H1 of the first micro protrusion MP1 to the second height H2 of the second micro protrusion MP2 may be in the range of 1.5 to 2.5. Preferably, the ratio of the first height H1 of the first micro protrusion MP1 to the second height H2 of the second micro protrusion MP2 may be 2. For example, the texture structure TS may be manufactured by embossing or injection molding, but is not limited thereto.

It is worth mentioning that by forming the above-mentioned texture structure TS, in addition to making the surface 100s of the light guide plate 100 have a paper-like touch, it can also enhance its reflective ability (i.e. glossiness) for light in a specific direction.

The following will list some other embodiments to illustrate the present disclosure in detail, wherein the same components will be marked with the same symbols, and the description of the same technical content will be omitted. For the omitted parts, please refer to the aforementioned embodiments, which will not be elaborated below.

FIG8A and FIG8B are three-dimensional schematic diagrams of the first optical microstructure and the second optical microstructure according to the second embodiment of the present invention. Please refer to FIG8A and FIG8B. Different from the semi-spun hammer-shaped optical microstructure of the aforementioned embodiment, the first optical microstructure MS1-A and the second optical microstructure MS2-A of this embodiment may have a fan-shaped appearance (as shown in FIG8B). Since the angle relationship between the two inclined surfaces of the optical microstructure of this embodiment and the bottom surface is similar to that of the aforementioned embodiment, the detailed description can refer to the relevant paragraphs of the aforementioned embodiment, and will not be repeated here.

FIG9 is a schematic cross-sectional view of a light source module according to the third embodiment of the present invention. Referring to FIG9 , the difference between the light source module LSM-A of the present embodiment and the light source module LSM of FIG2 is that the optical microstructure is set at a different position. Specifically, the ratio of the distance d" between the geometric center GC of the gap G between the first curved surface CS1 of the first optical microstructure MS1 of the light source module LSM-A and the second curved surface CS2 of the second optical microstructure MS2 and the surface 100s of the light guide plate 100A along the normal direction of the surface 100s (e.g., direction Z) to the thickness T of the light guide plate 100A is 0.25.

That is, in this embodiment, the first optical microstructure MS1 and the second optical microstructure MS2 are disposed on a side closer to the surface 100s of the light guide plate 100A, and the first optical microstructure MS1 is located between the second optical microstructure MS2 and the surface 100s. From another point of view, in this embodiment, the thickness t2" of the base material 112A of the substrate 110A is less than the thickness t1" of the base material 111A.

However, the present invention is not limited thereto. In another embodiment not shown, the ratio of the distance between the geometric center of the gap between the two curved surfaces of the two optical microstructures and the surface of the light guide plate to the thickness of the light guide plate may also be greater than 0.25 and less than or equal to 0.5. That is, the ratio may be in the range of 0.25 to 0.5.

Since the overlapping relationship between the first optical microstructure MS1 and the second optical microstructure MS2 of the light guide plate 100A and the effect on the light LB are similar to the first optical microstructure MS1 and the second optical microstructure MS2 of the light guide plate 100 in FIG. 2 , please refer to the relevant paragraphs of the aforementioned embodiment for detailed description, which will not be repeated here.

FIG10 is a schematic cross-sectional view of a light source module according to the fourth embodiment of the present invention. Referring to FIG10 , unlike the light source module LSM in FIG2 , the light source module LSM-B in this embodiment does not have the adhesive layer 115 in FIG2 filled between the first optical microstructure MS1 and the second optical microstructure MS2, but is replaced by an air gap AG.

For example, in this embodiment, the substrate 110B of the light guide plate 100B can be integrally formed and provided with a cavity CV. A plurality of first optical microstructures MS1 and a plurality of second optical microstructures MS2 of the light guide plate 100B are disposed in the cavity CV. Since the refractive index of the air layer is less than the refractive index of each of the first optical microstructure MS1 and the second optical microstructure MS2, the refractive effect of the first optical microstructure MS1 and the second optical microstructure MS2 on the light LB from the light source 120 and transmitted in the substrate 110B is similar to the first optical microstructure MS1 and the second optical microstructure MS2 of the light guide plate 100 of FIG. 2. For detailed description, please refer to the relevant paragraphs of the aforementioned embodiment, which will not be repeated here.

In summary, in a light source module of an embodiment of the present invention, a first optical microstructure and a second optical microstructure are embedded in the light guide plate. The two optical microstructures have two top angles facing each other and between 120 and 145 degrees and two bottom surfaces facing each other. In this way, in addition to preventing the optical microstructure from being exposed on the surface of the light guide plate and being scratched and unusable, the demand for highly collimated light can also be met.

100: Light guide plate

100es: bright surface

100is: light-entering surface

100s, 111s, 112s: surface

110: Substrate

111, 112: Base material

115: Adhesive layer

120: Light source

BS1: First bottom surface

BS2: Second bottom surface

CS1: First curved surface

CS2: Second curved surface

d: distance

G: Gap

GC: Geometry Center

LB: Light

LSM: Light Source Module

MS1: The first optical microstructure

MS2: Second optical microstructure

T:Thickness

VA1: First vertex

VA2: Second top angle

Z: Direction

Claims (10)

A light source module comprises: a light guide plate having a light incident surface and a light emitting surface and a surface connected to the light incident surface and opposite to each other, the light guide plate comprising: a substrate having the light emitting surface and the light incident surface; and a first optical microstructure and a second optical microstructure, which are arranged in the substrate and spaced between the light emitting surface and the surface, the first optical microstructure and the second optical microstructure overlap each other along the normal direction of the light emitting surface, the refractive index of each of the first optical microstructure and the second optical microstructure is different from the refractive index of the substrate, and the first optical microstructure has a first The first optical microstructure has a first bottom surface and a first top angle away from the first bottom surface, the second optical microstructure has a second bottom surface and a second top angle away from the second bottom surface, wherein the first bottom surface of the first optical microstructure is opposite to the second bottom surface of the second optical microstructure, the first top angle of the first optical microstructure and the second top angle of the second optical microstructure are opposite to each other, and the first top angle and the second top angle are respectively within the range of 120 degrees to 145 degrees; and a light source is arranged on one side of the light incident surface of the light guide plate, wherein the first optical microstructure also has a first inclined surface, A first curved surface and a second inclined surface, the first curved surface connects the first inclined surface and the second inclined surface, the second inclined surface is located between the first curved surface and the light incident surface, the first inclined surface and the second inclined surface define the first top angle, the second optical microstructure also has a third inclined surface, a second curved surface and a fourth inclined surface, the second curved surface connects the third inclined surface and the fourth inclined surface, the third inclined surface is located between the second curved surface and the light incident surface, the third inclined surface and the fourth inclined surface define the second top angle, the first curved surface of the first optical microstructure is along the normal of the light emitting surface of the light guide plate The fourth inclined surface of the second optical microstructure overlaps in the direction of the light guide plate, and the second curved surface of the second optical microstructure overlaps in the direction of the normal line of the light emitting surface of the light guide plate on the second inclined surface of the first optical microstructure. A gap is provided between the first curved surface of the first optical microstructure and the second curved surface of the second optical microstructure. The light guide plate has a thickness along the normal line of the light emitting surface. A geometric center of the gap has a distance from the light emitting surface or the surface along the normal line of the light emitting surface, and the ratio of the distance to the thickness is in the range of 0.25 to 0.5. The light source module as described in claim 1, wherein the angle between the first inclined surface of the first optical microstructure and the first bottom surface and the angle between the third inclined surface of the second optical microstructure and the second bottom surface are in the range of 20 degrees to 45 degrees. The light source module as described in claim 1, wherein the angle between the second inclined surface of the first optical microstructure and the first bottom surface and the angle between the fourth inclined surface of the second optical microstructure and the second bottom surface are in the range of 15 degrees to 25 degrees. The light source module as described in claim 1, wherein the first optical microstructure further has a fifth inclined surface connected to the second inclined surface, the second optical microstructure further has a sixth inclined surface connected to the fourth inclined surface, and the angle between the fifth inclined surface of the first optical microstructure and the first bottom surface and the angle between the sixth inclined surface of the second optical microstructure and the second bottom surface are in the range of 28 degrees to 38 degrees. The light source module as described in claim 1, wherein the ratio of the distance between the geometric center of the gap and the light-emitting surface along the normal direction of the light-emitting surface to the thickness is in the range of 0.25 to 0.5, and the first optical microstructure is located between the second optical microstructure and the light-emitting surface. The light source module as described in claim 1, wherein the ratio of the distance between the geometric center of the gap and the surface of the light guide plate along the normal direction of the light emitting surface to the thickness is in the range of 0.25 to 0.5, and the first optical microstructure is located between the second optical microstructure and the surface of the light guide plate. A light source module as described in claim 1, wherein the refractive index of the substrate is in the range of 1.4 to 1.65, and the refractive index of each of the first optical microstructure and the second optical microstructure is in the range of 1.69 to 1.81. A light source module as described in claim 1, wherein the surface is provided with a texture structure, the texture structure comprising: a plurality of first micro-protrusions extending in a first direction; and a plurality of second micro-protrusions extending in a second direction, the second direction intersecting the first direction, wherein the first micro-protrusions and the second micro-protrusions are alternately arranged along the first direction and the second direction, respectively, each of the first micro-protrusions has a first height along the normal direction of the surface, each of the second micro-protrusions has a second height along the normal direction of the surface, and the first height is different from the second height. The light source module as described in claim 8, wherein the first direction is parallel to the light incident surface, the second direction is perpendicular to the light incident surface, and the ratio of the first height of each of the first micro-protrusions to the second height of each of the second micro-protrusions is in the range of 1.5 to 2.5. A light source module as described in claim 1, wherein an air gap is provided between the first optical microstructure and the second optical microstructure, the substrate is integrally formed and provided with a chamber, and the first optical microstructure and the second optical microstructure are arranged in the chamber.

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