TWI574062B - Light guide plate and light source module - Google Patents

Description

Light guide plate and light source module

The present invention relates to an optical component and an optical module, and more particularly to a light guide plate and a light source module.

Conventional light source modules mostly use a LED light bar as a light source, and a light source is disposed on the side of the light guide plate in order to reduce the overall thickness of the light source module. However, when the distance between the light source and the light guide plate is too close, the light guide plate generates a hot spot corresponding to the area of the light-emitting diode on the light-emitting diode light strip, resulting in uneven light emission of the light source module. If the distance between the light source and the light guide plate is increased to improve the above-mentioned hot spot phenomenon, it is difficult to meet the requirement of a narrow bezel. Therefore, how to balance the uniformity of light and the demand for narrow borders is one of the problems that researchers in the field are eager to solve.

The "prior art" paragraphs are only intended to aid in understanding the present invention, and thus the disclosure of the "prior art" section may contain prior art that is not known to those of ordinary skill in the art. The content disclosed in the "Prior Art" section does not represent the content or the problem to be solved by one or more embodiments of the present invention, nor does it mean that it is known to those of ordinary skill in the art or prior to the present application. Cognition.

The invention provides a light guide plate which can achieve both light uniformity and a narrow bezel.

The invention provides a light source module which can have a narrow bezel and can provide a uniform surface light source.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein.

In order to achieve one or a part or all of the above or other purposes, an embodiment of the present invention provides a light guide plate having a light coupling region and a light exit region. The light guide plate includes a light incident surface, a light exit surface, a bottom surface, and a plurality of recessed structures. The coupling region is located between the light incident surface and the light exit region. The light exit surface is connected to the glossy surface. The bottom surface is connected to the light surface and opposite to the light exit surface. The recessed structure is located in the light-coupled region and is recessed in at least one of the light-emitting surface and the bottom surface, wherein the orthographic projection of each recessed structure on the concave surface (one of the light-emitting surface and the bottom surface) has a first side, a first Two sides and a third side connecting the first side and the second side. The first side and the second side meet , (x, y) are coordinates in the first direction and the second direction. The first direction is parallel to the light incident surface and the light exit surface. The second direction is perpendicular to the light incident surface. a and b are real numbers.

In order to achieve one or a part or all of the above or other purposes, an embodiment of the present invention provides a light source module including a light guide plate and a light source. The light guide plate has a light coupling area and a light exit area. The light guide plate includes a light incident surface, a light exit surface, a bottom surface, and a plurality of recessed structures. The coupling region is located between the light incident surface and the light exit region. The light exit surface is connected to the glossy surface. The bottom surface is connected to the light surface and opposite to the light exit surface. The recessed structure is located in the light-coupled region and is recessed in at least one of the light-emitting surface and the bottom surface, wherein the orthographic projection of each recessed structure on the concave surface (one of the light-emitting surface and the bottom surface) has a first side, a first Two sides and a third side connecting the first side and the second side. The first side and the second side meet , (x, y) are coordinates in the first direction and the second direction. The first direction is parallel to the light incident surface and the light exit surface. The second direction is perpendicular to the light incident surface. a and b are real numbers. The light source is located next to the entrance surface.

Based on the above, embodiments of the present invention have at least one of the following advantages or effects. The recessed structure in the coupling region helps to guide the light beam entering the light guide plate from the light incident surface, for example, the concave structure can make the light beam divergence in a direction parallel to the light incident surface (ie, the first direction), which helps The width of the coupling region in the second direction is reduced. Therefore, the light guide plate of the present invention can meet the requirements of light uniformity and narrow bezel, and the light source module of the present invention can have a narrow bezel and can provide a uniform surface light source. On the other hand, by adjusting the relative arrangement relationship between the recessed structure and the light-emitting elements in the light source, the recessed structure can also be used to converge the light beam in the first direction to modulate the brightness of the area of the surface light source emitted from the light guide plate. Therefore, the application range of the light source module of the present invention is improved, for example, the light source module can be applied to a regional lighting display and a stereoscopic (3D) display.

The above described features and advantages of the invention will be apparent from the following description.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only directions referring to the additional drawings. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

1A is a partial top plan view of a light source module in accordance with a first embodiment of the present invention. 1B is a cross-sectional view of the light guide plate of FIG. 1A in a first reference plane. 1C is a cross-sectional view of the light source module of FIG. 1A in a second reference plane. FIG. 1D illustrates the pattern of the first side and the second side of the recessed structure at different values of a and b. 2 is a partial top plan view of a light source module of a comparative example.

Referring to FIG. 1A to FIG. 1D , the light source module 100 includes a light guide plate 110 and a light source 120 . The light guide plate 110 has a light coupling area A1 and a light exit area A2. As shown in FIG. 1C , the light guide plate 110 includes a light incident surface SI, a light exit surface SO, a bottom surface SB, and a plurality of recess structures 112. The light coupling area A1 is located between the light incident surface SI and the light exit area A2. The light exit surface SO is connected to the light surface SI. The bottom surface SB is connected to the light surface SI and faces the light-emitting surface SO. The recess structure 112 is located in the coupling region A1 and is recessed in at least one of the light emitting surface SO and the bottom surface SB. In the present embodiment, the recessed structure 112 is recessed in the light-emitting surface SO and the bottom surface SB, wherein the recessed structure 1122 recessed into the light-emitting surface SO overlaps the recessed structure 1124 recessed into the bottom surface SB, but is not limited thereto.

The orthographic projection OP of each recessed structure 112 on the concave surface (including the orthographic projection of the recessed structure 1122 on the light exiting surface SO and the orthographic projection of the recessed structure 1124 on the bottom surface SB) has a first side E1, a second side E2, and a connection One side E1 and the third side E3 of the second side E2. The first side E1 and the second side E2 meet Where a, b are real numbers, and (x, y) are coordinates in the first direction D1 and the second direction D2. The first direction D1 is parallel to the light incident surface SI and the light exit surface SO. The second direction D2 is perpendicular to the light incident surface SI, and the first side E1 and the second side E2 have an axis of symmetry O1 parallel to the second direction D2. In this embodiment, the orthographic projection OP of each concave structure 112 on the concave surface is, for example, an isosceles triangle, wherein the first side E1, the second side E2, and the third side E3 are straight lines, respectively, but not limit.

For example, as shown in FIG. 1D, when the values of a and b are respectively equal to 1, the first side E1 and the second side E2 may respectively be curves. In addition, when the values of a and b are respectively close to 0, the first side E1 and the second side E2 may be straight lines respectively, wherein the angle θ1 between the first side E1 and the second side E2 (ie, the top of the isosceles triangle) The angle increases as the ratio of b to a (i.e., b/a) increases. The magnitude of the angle θ1 is proportional to the magnitude of the maximum width W112M of the third side E3 in the first direction D1, and the maximum width W112M affects the active area of the recessed structure 112. In the present embodiment, the angle θ1 falls within a range of, for example, 30 degrees to 120 degrees, that is, a and b satisfy .

As shown in FIG. 1B, the slit line SL1 of each recessed structure 112 on the first reference plane R1 parallel to the light incident surface SI may be a curve, and the curve is in a third direction perpendicular to the first direction D1 and the second direction D2. D3 has an axis of symmetry O2. In another embodiment, the stub line SL1 can also be a fold line. For example, the cross-sectional shape of each recessed structure 112 on the first reference plane R1 parallel to the light incident surface SI may be V-cut, and the fold line also has an axis of symmetry O2 in the third direction D3, but Not limited to this.

As shown in FIG. 1C, the variation of the depth H112 of each recessed structure 112 in the second direction D2 may include a stepwise decrease or a stepwise increase. It should be noted that FIG. 1C only shows the appearance of the depth H112 of the recess structure 112 gradually increasing in the second direction D2, but is not limited thereto. In other embodiments, the depth H112 of the recessed structure 112 may also be gradually decreasing, increasing first, then decreasing, or decreasing first and then increasing in the second direction D2. Further, the ratio of the maximum width W112M (refer to FIG. 1A) of the third side E3 of each recess structure 112 in the first direction D1 to the maximum depth H112M of the recess structure 112 is, for example, not less than 5.

Each of the recessed structures 112 has a first surface S1 and a second surface S2, wherein the first surface S1 is located between the light incident surface SI and the second surface S2. In this embodiment, the section SL1 of the first surface S1 on the second reference plane R2 perpendicular to the light incident surface SI and the light exiting surface SO and the section SL3 of the second surface S2 on the second reference plane R2 are both Straight line, but not limited to this. In another embodiment, one of the cut lines SL2, SL3 may be a straight line, and the other of the cut lines SL2, SL3 may be a curve. Alternatively, the cut lines SL2, SL3 may all be curved.

The light source 120 is located beside the light incident surface SI, which may include a plurality of light emitting elements 122. As shown in FIG. 1A, the light emitting elements 122 may be arranged along the first direction D1, wherein each of the recess structures 112 are respectively located in front of one of the light emitting elements 122, and each of the light emitting elements 122 corresponds to at least one of the recess structures 112. . In other words, the light-emitting element 122 and the recessed structure 112 can be disposed in a one-to-one relationship, but not limited thereto. For example, the light-emitting element 122 and the recess structure 112 may also have a one-to-many arrangement relationship. In this embodiment, the light source 120 may further include a circuit board 124, wherein the light emitting element 122 is disposed on the circuit board 124, and the light emitting element 122 is located between the light incident surface SI and the circuit board 124.

Referring to FIG. 1A and FIG. 2 simultaneously, the light-emitting element 122 faces the light incident surface SI and is adapted to emit the light beam L toward the light incident surface SI. The divergence angle θ2 of the light beam L converges on the light incident surface SI due to the refraction. The oblique line areas in FIGS. 1A and 2 indicate the illumination range (ie, the bright area) of each of the light-emitting elements 122 in the light-coupled area A1, and the area other than the oblique line area in the light-coupled area A1 is a dark area. The line connecting the intersection point X of the adjacent two bright areas in the first direction D1 is defined as the boundary I between the coupling area A1 and the light exit area A2. Since the obvious light and dark distribution of the coupling area A1 affects the uniformity of the surface light source, the coupling area A1 needs to be shielded to avoid affecting the visual effects of the light source modules 100 and 200. In other words, the larger the coupling area A1, the harder it is to achieve a narrow bezel.

As shown in the light source module 200 of FIG. 2, under the recess structure (such as the recess structure 112 of FIG. 1A), the light beam L incident on the light-coupled region A1 is transmitted in the direction of the light-emitting region A2, wherein the light guide plate 210 The magnitude of the distance A' between the boundary I and the light source 120 depends mainly on the divergence angle θ2 of the light-emitting element 122 and the refractive index of the light guide plate 210. In contrast, as shown in the light source module 100 of FIG. 1A , the light beam L incident on the coupling light region A1 is totally reflected by the recessed structure 112 and then diverges to both sides of the symmetry axis O1, thereby expanding the illumination range. At the same pitch P of the light-emitting elements 122, the distance A between the boundary I and the light source 120 can be smaller than the distance A' of FIG. In other words, the arrangement of the recessed structure 112 helps to reduce the A/P ratio (Active area/Pitch ratio) in addition to narrowing the bezel of the light source module 100. In the case where the A/P ratio is fixed, since the distance A between the boundary I and the light source 120 can be smaller than the distance A' of FIG. 2, the present embodiment can reduce the light-emitting element 122 by increasing the pitch P of the light-emitting elements 122. The number thus helps to reduce the cost of the light source 120 and can be both thermally stable.

In addition, since the recessed structure 112 can increase the degree of divergence of the light beam L, and help to increase the proportion of the light beam L incident at a large angle into and out of the light area A2, the brightness of the large-angle light beam L emitted from the light exiting area A2 is improved, thereby It helps to improve the light uniformity of the light source module 100 and the viewing angle of the light source module 100. Furthermore, the diverging structure 112 is used to enhance the divergence characteristic of the light beam L. In this embodiment, the divergence angle θ2 of the light-emitting element 122 and the refractive index of the light guide plate 210 are reduced for the illumination range, and thus the setting of the recess structure 112 is also helpful. The degree of freedom in selecting the light-emitting element 122 is improved.

Other embodiments of the light source module and the light guide plate of the present invention will be described below with reference to FIGS. 3 to 5. 3 to 5 are partial top views of the light source module according to the second to fourth embodiments of the present invention, respectively. Referring to FIG. 3, the light source module 300 is similar to the light source module 100, and similar or identical elements are denoted by the same reference numerals and will not be described again. The main difference between the light source module 300 and the light source module 100 is that the concave projections 312 of the light guide plate 310 have a fourth side E4 on the concave projection surface (such as the light exit surface SO), and the fourth side E4. It is connected between the first side E1 and the second side E2, and the fourth side E4 is located between the light incident surface SI and the third side E3. In this embodiment, the orthographic projection OP1 of each recessed structure 312 on the light-emitting surface SO is, for example, a trapezoid, wherein the first side E1, the second side E2, the third side E3, and the fourth side E4 are straight lines, respectively, but not Limited.

Referring to FIG. 4, the light source module 400 is similar to the light source module 100, and similar or identical elements are denoted by the same reference numerals and will not be described again. The main difference between the light source module 400 and the light source module 100 is that the portion 412 of the light guide plate 410 in the light coupling area A1 and the portion 414 of the light guide plate 410 in the light exit area A2 are independent of each other. The portions 412 of the light-guiding region A1 and the portion 414 of the light-guide plate 410 in the light-emitting region A2 are separately fabricated and not integrally formed, wherein the portion 412 of the light-guiding plate 410 in the light-coupled region A1 may be one. The light-guiding plate 410 can be a separate light-guiding member in the portion 414 of the light-emitting area A2. In order to accurately align the portion 412 and the portion 414, the portion 412 and the portion 414 can be fixed to each other through the adhesive bonding or the mechanism clamping limit, but not limited thereto. For example, when the light source module 400 is longitudinally disposed (upright), such as when the portion 412 is between the portion 414 and the ground, the portion 414 will bear against the portion 412 due to gravity. Thus, the adhesive layer or the stopper mechanism can be omitted.

In the above embodiment, the recessed structures 112, 312 are all disposed in front of the light-emitting element 122 to achieve the effect of diverging the light beam L, but the invention is not limited thereto. Referring to FIG. 5, the light source module 500 is similar to the light source module 100, and similar or identical elements are denoted by the same reference numerals and will not be described again. The main difference between the light source module 500 and the light source module 100 is that the recessed structures 112 in the light source module 500 are respectively disposed between any two adjacent light emitting elements 122. Under this architecture, the light beam L incident on the coupling light region A1 is totally reflected by the recess structure 112 and then diverges to the sides of the symmetry axis O1, so that the light beam L is directed between the adjacent recess structures 112 (or the front of the light emitting element 122). ) Convergence. In this configuration, the recessed structure 112 can be used to converge the light beam L in the first direction D1, and is adapted to modulate the brightness of the area of the surface light source emitted from the light guide plate 510, for example, to form a region of the light guide plate 510 corresponding to the light-emitting element 122. The bright area, and the light guide plate 510 corresponding to the area between the light-emitting elements 122 form a dark area, thereby improving the application range of the light source module 500, for example, the light source module 500 can be applied to the local lighting (Local Dimming) display and stereo (3D) Display, etc.

In summary, embodiments of the present invention have at least one of the following advantages or benefits. The recessed structure in the coupling region helps to guide the light beam entering the light guide plate from the light incident surface. For example, the recessed structure allows the light beam to diverge in a direction parallel to the light incident surface (ie, the first direction) to help reduce the width of the light coupling region in the second direction. Therefore, the light guide plate of the present invention can meet the requirements of light uniformity and narrow bezel, and the light source module of the present invention can have a narrow bezel and can provide a uniform surface light source. On the other hand, by adjusting the relative arrangement relationship between the recessed structure and the light-emitting elements in the light source, the recessed structure can also be used to converge the light beam in the first direction to modulate the brightness of the area of the surface light source emitted from the light guide plate. Thereby, the application range of the light source module of the invention is improved.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention. In addition, the terms "first", "second" and the like mentioned in the specification or the scope of the claims are only used to name the elements or distinguish different embodiments or ranges, and are not intended to limit the number of elements. Upper or lower limit.

100, 200, 300, 400, 500: light source module 110, 210, 310, 410, 510: light guide plate 112, 312: recess structure 120: light source 122: light-emitting element 124: circuit board 412, 414: part A, A ': distance A1: coupling area A2: light exit area D1: first direction D2: second direction D3: third direction E1: first side E2: second side E3: third side E4: fourth side H112: depth H112M: maximum depth I: boundary L: beam O1, O2: axis of symmetry OP, OP1: orthographic projection P: pitch R1: first reference plane R2: second reference plane SB: bottom surface SI: light incident surface SL1, SL2 SL3: Cut line SO: Light exit surface W112M: Maximum width X: Intersection point θ1: Angle θ2: Divergence angle

1A is a partial top plan view of a light source module in accordance with a first embodiment of the present invention. 1B is a cross-sectional view of the light guide plate of FIG. 1A in a first reference plane. 1C is a cross-sectional view of the light source module of FIG. 1A in a second reference plane. FIG. 1D illustrates the pattern of the first side and the second side of the recessed structure at different values of a and b. 2 is a partial top plan view of a light source module of a comparative example. 3 to 5 are partial top views of the light source module according to the second to fourth embodiments of the present invention, respectively.

100: light source module 110: light guide plate 112: recessed structure 120: light source 122: light-emitting element 124: circuit board A: distance A1: light-coupled area A2: light-emitting area D1: first direction D2: second direction D3: third Direction E1: First side E2: Second side E3: Third side I: Junction L: Beam O1: Symmetry axis OP: Orthographic projection P: Pitch R1: First reference plane R2: Second reference plane SI: Into light Surface SO: illuminating surface W112M: maximum width X: intersection point θ2: divergence angle

Claims (15)

A light guide plate having a light-coupled region and a light-emitting region, the light guide plate comprising: a light-incident surface, the light-coupled region is located between the light-incident surface and the light-emitting region; and a light-emitting surface is connected to the light-incident surface; a bottom surface connecting the light incident surface and opposite to the light emitting surface; and a plurality of concave structures located in the light coupling region and recessed in at least one of the light emitting surface and the bottom surface, wherein each of the concave structures is The orthographic projection of the concave surface has a first side, a second side, and a third side connecting the first side and the second side, the first side and the second side satisfying (x, y) is a coordinate in a first direction and a second direction, the first direction being parallel to the light incident surface and the light exit surface, the second direction being perpendicular to the light incident surface, a, b For real numbers, where a and b satisfy 0.0718 3. The light guide plate of claim 1, wherein each of the concave structures is a curve or a broken line on a first reference plane parallel to the light incident surface, and the curve or the fold line is vertical A third axis in the first direction and the second direction has an axis of symmetry. The light guide plate of claim 1, wherein each of the recessed structures has a first surface and a second surface, the first surface being located between the light incident surface and the second surface, the first surface being A line perpendicular to the light incident surface and a second reference plane of the light exiting surface is a straight line or a curved line, and a line of the second surface on the second reference plane is a straight line or a curved line. The light guide plate of claim 1, wherein the portion of the light guide plate in the light coupling region and the portion of the light guide plate in the light exit region are independent of each other. A light source module includes: a light guide plate having a light-coupled region and a light-emitting region, the light guide plate includes: a light-incident surface, the light-coupled region is located between the light-incident surface and the light-emitting region; Connecting the light incident surface; a bottom surface connecting the light incident surface and opposite to the light emitting surface; and a plurality of concave structures located in the light coupling region and recessed in at least one of the light emitting surface and the bottom surface, The orthographic projection of each of the recessed structures on the recessed surface has a first side, a second side, and a third side connecting the first side and the second side, the first side and the second side Satisfy (x, y) is a coordinate in a first direction and a second direction, the first direction being parallel to the light incident surface and the light exit surface, the second direction being perpendicular to the light incident surface, a, b Included as a real number; and a light source located beside the light entrance surface, where a and b satisfy 0.0718 3. The light source module of claim 5, wherein the change in the depth of each of the recessed structures in the second direction comprises stepwise decreasing or stepwise incrementing, and the third side of each of the recessed structures is at the first The ratio of the maximum width in the direction to the maximum depth of the recessed structure is not less than 5. The light source module of claim 5, wherein the orthographic projection of each of the recessed structures on the concave surface further has a fourth side, the fourth side being connected to The first side is between the first side and the second side, and the fourth side is located between the light incident surface and the third side. The light source module of claim 5, wherein each of the concave structures is a curve or a broken line on a first reference plane parallel to the light incident surface, and the curved line or the broken line is A third axis perpendicular to the first direction and the second direction has an axis of symmetry. The light source module of claim 5, wherein each of the recessed structures has a first surface and a second surface, the first surface being located between the light incident surface and the second surface, the first surface A section line perpendicular to the light incident surface and a second reference plane of the light exiting surface is a straight line or a curved line, and a line of the second surface on the second reference plane is a straight line or a curved line. The light source module of claim 5, wherein the portion of the light guide plate in the light coupling region and the portion of the light guide plate in the light exit region are independent of each other. The light source module of claim 5, wherein the light source comprises a plurality of light emitting elements, and the light emitting elements are arranged along the first direction. The light source module of claim 11, wherein each of the recessed structures is located in front of one of the light emitting elements, and each of the light emitting elements corresponds to at least one of the recessed structures. The light source module of claim 11, wherein the recessed structures respectively correspond between any two adjacent light-emitting elements of the light-emitting elements. A light guide plate has a light-coupled region and a light-emitting region, the light guide plate includes: a light-incident surface, the light-coupled region is located between the light-incident surface and the light-emitting region; and a light-emitting surface is connected to the light-incident surface; a bottom surface connecting the light incident surface and opposite to the light emitting surface; and a plurality of concave structures located in the light coupling region and recessed in at least one of the light emitting surface and the bottom surface, wherein each of the concave structures is The orthographic projection of the concave surface has a first side, a second side, and a third side connecting the first side and the second side, the first side and the second side satisfying (x, y) is a coordinate in a first direction and a second direction, the first direction being parallel to the light incident surface and the light exit surface, the second direction being perpendicular to the light incident surface, a, b a real number, wherein the change in the depth of each of the recessed structures in the second direction comprises a stepwise decreasing or stepwise increment, and a maximum width of the third side of each of the recessed structures in the first direction and a maximum of the recessed structure The ratio of depth is not less than 5. A light guide plate having a light-coupled region and a light-emitting region, the light guide plate comprising: a light-incident surface, the light-coupled region is located between the light-incident surface and the light-emitting region; and a light-emitting surface is connected to the light-incident surface; a bottom surface connecting the light incident surface and opposite to the light emitting surface; and a plurality of concave structures located in the light coupling region and recessed in at least one of the light emitting surface and the bottom surface, wherein each of the concave structures is The orthographic projection of the concave surface has a first side, a second side, and a third side connecting the first side and the second side, the first side and the second side satisfying (x, y) is a coordinate in a first direction and a second direction, the first direction being parallel to the light incident surface and the light exit surface, the second direction being perpendicular to the light incident surface, a, b a real number, wherein the orthographic projection of each of the concave structures on the concave surface further has a fourth side, the fourth side is connected between the first side and the second side, and the fourth side is located in the Between the smooth side and the third side.