TW201604598A - Light guide plate and light source module - Google Patents

Abstract

A light guide plate including a first substrate, a second substrate opposite to the first substrate, a plurality of first microstructures, a plurality of second microstructures, and a plurality of third microstructures is provided. The first substrate has a light emitting surface, a first bottom surface opposite to the light emitting surface, and a light incidence surface connecting the light emitting surface and the first bottom surface. The first bottom surface is located between the light emitting surface and the second substrate. The second substrate has a top surface and a second bottom surface. The top surface is opposite to the second bottom surface and located between the first substrate and the second bottom surface. The first microstructures and the second microstructures are disposed on the light emitting surface and the second bottom surface respectively and extend along a first direction parallel to the light incidence surface respectively. The third microstructures are connected between the first bottom surface and the top surface and extend along a second direction perpendicular to the light incidence surface respectively. A light source module is also provided.

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.

Generally, the light source module can be mainly divided into a direct light source module and a side input light source module according to different positions of the light source. For example, the side light source module is disposed on the side of the light guide plate, so that the light beam emitted from the light source enters the light guide plate from the side of the light guide plate.

The side-entry light source module usually has two cymbals and two diffusion sheets on the light-emitting surface of the light guide plate to enhance brightness and light uniformity. However, these optical films are easy to absorb or scatter part of the light beam due to factors such as material or surface characteristics, and cause a certain amount of light loss, so that the light extraction efficiency of the light source module cannot be effectively improved. Especially when the light beam is transmitted to the cymbal, part of the light beam is easily unable to be effectively utilized due to Fresnel reflection. Therefore, how to effectively improve the light extraction efficiency is one of the problems that researchers in this field are eager to solve.

The present invention provides a light guide plate that can collimate a light beam.

The invention further provides a light source module, which has good light extraction efficiency.

A light guide plate of the present invention is adapted to be disposed beside the light source. The light guide plate includes a first substrate, a second substrate, a plurality of first microstructures, a plurality of second microstructures, and a plurality of third microstructures. The second substrate is opposite to the first substrate. The first substrate has a light emitting surface, a first bottom surface, and a light incident surface. The first bottom surface is opposite to the light emitting surface and is located between the light emitting surface and the second substrate. The light incident surface is connected to the light emitting surface and the first bottom surface, and the light source is disposed beside the light incident surface. The second substrate has a top surface and a second bottom surface. The top surface is opposite to the second bottom surface and is located between the first substrate and the second bottom surface. The first microstructures are disposed on the light exit surface and extend in a first direction parallel to the light incident surface, respectively. The second microstructure is disposed on the second bottom surface and extends in the first direction, respectively. The third microstructure is coupled between the first bottom surface and the top surface and extends in a second direction perpendicular to the light incident surface, respectively.

In an embodiment of the invention, each of the first microstructures has a first side surface and a first light guiding surface. The first side is located between the first light guiding surface and the light incident surface, and an angle between the first light guiding surface and the light emitting surface in the first substrate is greater than 0 degrees and less than or equal to 5 degrees. Each of the second microstructures has a second side and a second light guiding surface. The second side is located between the second light guiding surface and the light incident surface, and the corners of the second light guiding surface and the second bottom surface in the second substrate are in a range of 25 degrees to 35 degrees.

In an embodiment of the invention, each of the third microstructures has a first connection surface, a second connection surface, a third connection surface, and a fourth connection surface. The first connecting surface is connected to the first bottom surface. The second connecting surface is connected to the top surface. Third connection surface and fourth The connecting faces are respectively connected to the first connecting face and the second connecting face, and the width of the first connecting face in the first direction is smaller than the width of the second connecting face in the first direction.

In an embodiment of the invention, the third connecting surface and the top surface are in a range of 60 degrees to 70 degrees in the corner of the third microstructure, and the fourth connecting surface and the top surface are in the third microstructure. The inner corner of the clip is in the range of 60 to 70 degrees.

In an embodiment of the invention, the materials of the first substrate, the second substrate, the first microstructure, the second microstructure, and the third microstructure are the same.

In an embodiment of the invention, the light exiting surface, the first bottom surface, the top surface, and the second bottom surface are parallel to each other.

In an embodiment of the invention, the light guide plate further includes a reflective layer. The reflective layer is disposed on the second microstructure and disposed on a region of the second bottom surface that is not covered by the second microstructure.

A light source module of the present invention includes a light source and the above-described light guide plate.

In an embodiment of the invention, the light source module further includes a diffusion sheet, wherein the first microstructure is located between the diffusion sheet and the first substrate.

Based on the above, the light guide plate of the above-described embodiment of the present invention collimates the light beam by the arrangement of the first microstructure, the second microstructure, and the third microstructure. Therefore, the light source module applying the above-mentioned light guide plate can omit the setting of the cymbal, so that the light extraction efficiency can be effectively improved.

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

100‧‧‧Light source module

110‧‧‧Light source

112‧‧‧Lighting elements

120‧‧‧Light guide

121‧‧‧First substrate

122‧‧‧second substrate

123‧‧‧First microstructure

124‧‧‧Second microstructure

125‧‧‧ Third microstructure

130‧‧‧Diffuser

B, B', BB, BB’‧‧‧ beams

C‧‧‧cavity

D1, D2, D3‧‧‧ distance

SB1‧‧‧ first bottom

SB2‧‧‧ second bottom surface

SC1‧‧‧ first connection surface

SC2‧‧‧second connection surface

SC3‧‧‧ third connection surface

SC4‧‧‧4th connection surface

SE‧‧‧Glossy

SG1‧‧‧first light guide

SG2‧‧‧second light guide

SI‧‧‧Into the glossy surface

SS1‧‧‧ first side

SS2‧‧‧ second side

ST‧‧‧ top surface

W1, W2‧‧‧ width

X1‧‧‧ first direction

X2‧‧‧ second direction

Θ1, θ2, θ3, θ4‧‧‧ angle

1 is a schematic diagram of a light source module in accordance with an embodiment of the invention.

2 is a partially enlarged schematic view of the first substrate, the second substrate, and the second microstructure of FIG. 1.

3 and 4 are schematic cross-sectional views of the light source module of FIG. 1.

1 is a schematic diagram of a light source module in accordance with an embodiment of the invention. 2 is a partially enlarged schematic view of the first substrate, the second substrate, and the second microstructure of FIG. 1. Referring to FIGS. 1 and 2 , the light source module 100 includes a light source 110 and a light guide plate 120 . Light source 110 includes, for example, a plurality of light emitting elements 112. 1 shows that the number of light-emitting elements 112 is four, but this embodiment does not need to limit the number of light-emitting elements 112. Each of the light-emitting elements 112 is, for example, a light-emitting diode (LED), but is not limited thereto. In another embodiment, the light source 110 can also replace the light-emitting elements 112 with a light tube.

The light guide plate 120 includes a first substrate 121, a second substrate 122, a plurality of first microstructures 123, a plurality of second microstructures 124, and a plurality of third microstructures 125. 1 shows that the number of the first microstructure 123, the second microstructure 124, and the third microstructure 125 are 5, 5, and 8, respectively, but the embodiment does not need to define the first microstructure 123 and the second microstructure 124. And the number of third microstructures 125.

The first substrate 121 is opposite to the second substrate 122. The first substrate 121 has The light emitting surface SE, the first bottom surface SB1, and the light incident surface SI. The first bottom surface SB1 is opposite to the light-emitting surface SE and is located between the light-emitting surface SE and the second substrate 122. The light incident surface SI is connected to the light emitting surface SE and the first bottom surface SB1. The light source 110 is disposed beside the light incident surface SI, and each of the light emitting elements 112 is arranged, for example, along the long side of the light incident surface SI. In another embodiment, when the light source 110 replaces the light emitting elements 112 with a light tube, the extending direction of the light tube is parallel to the long side of the light incident surface SI.

The second substrate 122 has a top surface ST and a second bottom surface SB2. The top surface ST is opposite to the second bottom surface SB2 and is located between the first substrate 121 and the second bottom surface SB2. In the present embodiment, the light-emitting surface SE, the first bottom surface SB1, the top surface ST, and the second bottom surface SB2 are parallel to each other.

The first microstructures 123 are disposed on the light exit surface SE and extend in a first direction X1 parallel to the light incident surface SI, respectively, and are arranged, for example, in a second direction X2 perpendicular to the light incident surface SI. Further, the adjacent two first microstructures 123 are separated by a distance D1, and the distance D1 of the present embodiment is reduced, for example, as the distance from the light incident surface SI increases, but is not limited thereto.

The second microstructures 124 are disposed on the second bottom surface SB2 and extend in the first direction X1, respectively, and are arranged, for example, in the second direction X2. In other words, the second microstructure 124 is disposed, for example, in parallel with the first microstructure 123. Further, the adjacent two second microstructures 124 are separated by a distance D2, and the distance D2 of the present embodiment is reduced, for example, as the distance from the light incident surface SI increases, but is not limited thereto.

In this embodiment, the shape of each of the first microstructures 123 and the shape of each of the second microstructures 124 are, for example, triangular prisms, and each of the first microstructures 123 has a first a side surface SS1 and a first light guiding surface SG1, wherein the first side surface SS1 is located between the first light guiding surface SG1 and the light incident surface SI, and the first light guiding surface SG1 and the light emitting surface SE have an angle in the first substrate 121. Θ1. In addition, each of the second microstructures 124 has a second side surface SS2 and a second light guiding surface SG2, wherein the second side surface SS2 is located between the second light guiding surface SG2 and the light incident surface SI, and the second light guiding surface SG2 and The two bottom surfaces SB2 have an included angle θ2 in the second substrate 122. By adjusting the angle θ1 and the angle θ2, the angle at which the light beam is emitted from the light guide plate 120 can be controlled. In the present embodiment, the angle θ1 is greater than 0 degrees and less than or equal to 5 degrees, and the included angle θ2 falls within the range of 25 degrees to 35 degrees, so that the light beam is collimated in the second direction X2, and the self-light guide plate 120 is lifted. The proportion of the beam that is emitted in the forward direction. In a preferred embodiment, the included angle θ1 is 1 degree and the included angle θ2 is 31 degrees.

The third microstructures 125 are connected between the first bottom surface SB1 and the top surface ST, and extend in the second direction X2, respectively, and are arranged along the first direction X1. In other words, the orthographic projection of the third microstructure 125 on the light exit surface SE is staggered to the first microstructure 123, and the orthographic projection of the third microstructure 125 on the second bottom surface SB2 is staggered to the second microstructure 124.

In this embodiment, the shape of each of the third microstructures 125 is, for example, a trapezoidal column. As shown in FIG. 2, each of the third microstructures 125 has a first connection surface SC1, a second connection surface SC2, a third connection surface SC3, and a fourth connection surface SC4. The first connection surface SC1 is connected to the first bottom surface SB1. The second connection surface SC2 is connected to the top surface ST. The third connection surface SC3 and the fourth connection surface SC4 are connected to the first connection surface SC1 and the second connection surface SC2, respectively.

According to the principle of étendue, the larger the cross-sectional area, the smaller the solid angle. Therefore, this embodiment causes the first connection surface SC1 to be in the first direction X1. The width W1 is smaller than the width W2 of the second connection surface SC2 in the first direction X1 such that the cross-sectional area of the third microstructure 125 on the first bottom surface SB1 is smaller than the third microstructure 125 on the top surface ST. Cross-sectional area. As such, the light spread of the light beam entering the third microstructure 125 from the first connection surface SC1 can be reduced, thereby collimating the light beam in the first direction X1.

However, as shown by the broken line in FIG. 2, after the light beam enters the third microstructure 125 from the first substrate 121, the light beam B reflected by the second bottom surface SB2 of the second substrate 122 is again reflected by the third microstructure 125, The effect of collimation cannot be achieved. In order to improve the above situation, the present embodiment modulates the angle θ3 between the third connection surface SC3 and the top surface ST in the third microstructure 125 and the angle θ4 between the fourth connection surface SC4 and the top surface ST in the third microstructure 125. To prevent the light beam B' from the second bottom surface SB2 (shown by the solid line in FIG. 2) being secondarily reflected by the third microstructures 125, so that the light beam B' from the second bottom surface SB2 is directly emitted from the third microstructures 125. To achieve the effect of collimation. For example, the included angle θ3 and the included angle θ4 fall within the range of 60 degrees to 70 degrees, respectively, and the included angle θ3 and the included angle θ4 are preferably 66 degrees, respectively, and the width W1 is 20 μm.

In this embodiment, the materials of the first substrate 121, the second substrate 122, the first microstructure 123, the second microstructure 124, and the third microstructure 125 may all be the same, for example, by polymethyl methacrylate (PMMA). Made. In addition, the first substrate 121 and the first microstructure 123 may be fabricated together, and the second substrate 122, the second microstructure 124, and the third microstructure 125 may be fabricated together. The production together is, for example, injection molding together, but is not limited thereto. And, the third microstructure 125 and the first substrate 121 A bottom surface SB1 is joined to each other by, for example, an optical glue such as a photo-curable adhesive. An optical glue (not shown) is located, for example, at an interface where the first bottom surface SB1 is in contact with the first connection surface SC1. Further, the transmission medium of the light beam in the cavity C surrounded by the adjacent two third microstructures 125, the first substrate 121, and the second substrate 122 is air. However, the present invention is not required to limit the method of fabricating the light guide plate 120. For example, the first substrate 121, the first microstructure 123, and the third microstructure 125 may be fabricated together, and the second substrate 122 and the second microstructure 124 may be fabricated together, and the third microstructure 125 and the second substrate 122 The top surfaces ST are joined to each other by optical glue. Alternatively, the first substrate 121, the second substrate 122, the first microstructure 123, the second microstructure 124, and the third microstructure 125 may be separately fabricated and bonded to each other by optical glue.

The light guide plate 120 of the present embodiment may further provide a reflective layer (not shown) on the second microstructure 124 and the region where the second bottom surface SB2 is not covered by the second microstructure 124, and transmit the reflection to the second microstructure 124. Or the light beam of the second bottom surface SB2, and avoiding the light beam from being emitted from the bottom surface of the light guide plate 120. The reflective layer is formed by, for example, forming a material having reflective properties on the second microstructure 124 and on the region of the second bottom surface SB2 that is not covered by the second microstructure 124. For example, silver may be plated on the second microstructure 124 and the region of the second bottom surface SB2 not covered by the second microstructure 124, so that the reflective layer conforms to the second microstructure 124 and the second bottom surface SB2 is not The area covered by the two microstructures 124 is not limited thereto.

In addition, the light source module 100 of the embodiment may further include a diffusion sheet 130 on the light guide plate 120, so that the first microstructure 123 is located on the diffusion sheet 130 and the first substrate. Between 121, the light uniformity of the light source module 100 is improved.

3 and FIG. 4 are schematic cross-sectional views of the light source module of FIG. 1. The difference between FIG. 3 and FIG. 4 is that FIG. 3 is a cross-sectional view of the third microstructure 125, and FIG. 4 is a cross section of the cavity C. Figure. Referring to FIG. 3 and FIG. 4 , the light beam emitted by the light source 110 enters the first substrate 121 of the light guide plate 120 from the light incident surface SI. As shown in FIG. 3, a portion of the light beam BB entering the first substrate 121 is incident into the third microstructure 125, and is transmitted to the bottom surface of the light guide plate 120 through the top surface ST (such as the second bottom surface SB2 or the second micro The structure 124) is reflected by the bottom surface of the light guide plate 120. The light beam BB reflected by the bottom surface of the light guide plate 120 may be directly emitted from the light exit surface SE or transmitted to the bottom surface of the light guide plate 120 via the reflection of the first microstructure 123. The first microstructure 123 is adapted to deflect the light beam BB such that the incident light angle of the light beam BB that is again transmitted to the bottom surface of the light guide plate 120 is reduced, so that the light beam BB reflected by the bottom surface of the light guide plate 120 has a chance to self-illuminate the light surface SE Exit. Under the optical path architecture of FIG. 3, by modulating the distribution density of the second microstructures 124 (eg, the distance D2 between the adjacent two second microstructures 124), the amount of light emitted by each region of the light guide plate 120 can be controlled, By appropriately adjusting the distribution density of the second microstructures 124, the light uniformity can be effectively improved.

In addition, as shown in FIG. 4, a portion of the light beam BB' entering the first substrate 121 is transmitted to the first bottom surface SB1 not in contact with the third microstructure 125, and most of the light beam BB' is due to total internal reflection (total internal The reflection is transmitted back and forth between the first light guiding surface SG1 of the first microstructure 123 and the first bottom surface SB1. By deflecting the beam BB' by the first microstructure 123, the angle of incidence of the beam BB' delivered to the first bottom surface SB1 is reduced, thereby allowing the beam BB' to pass through the cavity C to transmit light. The bottom surface of the plate 120 (such as the second bottom surface SB2 or the second microstructure 124) is again emitted from the light exit surface SE via reflection of the bottom surface of the light guide plate 120. In the optical path architecture of FIG. 4, by modulating the distribution density of the first microstructures 123 (eg, the distance D1 between the adjacent two first microstructures 123), the amount of light emitted by each region of the light guide plate 120 can be controlled, and The loss of the light beam BB' caused by the back-and-forth reflection in the first substrate 121 is reduced. Therefore, by appropriately adjusting the distribution density of the first microstructures 123, the light uniformity and the light-emitting efficiency can be effectively improved.

The ratio of the above-mentioned light beams BB, BB' depends on the distance D3 (shown in FIG. 2) between the adjacent two third microstructures 125. In the present embodiment, the third microstructures 125 are, for example, equidistantly arranged. And the distance D3 is equal to, for example, the width W1, but is not limited thereto.

In summary, the light guide plate of the above embodiment of the present invention collimates the light beam by the arrangement of the first microstructure, the second microstructure, and the third microstructure. Therefore, the light source module applying the light guide plate can omit the setting of the cymbal, thereby solving the negative influence of the Fresnel reflection phenomenon on the light utilization efficiency under the structure of setting the cymbal, and effectively improving the light extraction efficiency. . In addition, in an embodiment, the distribution density of the first microstructure may be modulated to improve the uniformity of light emission of the light source module, and the distribution density of the second microstructure may be modulated to enhance the light source mode. The light uniformity and light extraction efficiency of the group.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Light source module

110‧‧‧Light source

112‧‧‧Lighting elements

120‧‧‧Light guide

121‧‧‧First substrate

122‧‧‧second substrate

123‧‧‧First microstructure

124‧‧‧Second microstructure

125‧‧‧ Third microstructure

130‧‧‧Diffuser

D1, D2, D3‧‧‧ distance

SB1‧‧‧ first bottom

SB2‧‧‧ second bottom surface

SE‧‧‧Glossy

SG1‧‧‧first light guide

SG2‧‧‧second light guide

SI‧‧‧Into the glossy surface

SS1‧‧‧ first side

SS2‧‧‧ second side

ST‧‧‧ top surface

X1‧‧‧ first direction

X2‧‧‧ second direction

Θ1, θ2‧‧‧ angle

Claims (15)

A light guide plate is disposed adjacent to a light source, the light guide plate includes: a first substrate; a second substrate opposite to the first substrate, the first substrate has a light emitting surface, a first bottom surface, and an input a light surface, the first bottom surface is opposite to the light emitting surface and located between the light emitting surface and the second substrate, the light incident surface is connected to the light emitting surface and the first bottom surface, and the light source is disposed beside the light incident surface. The second substrate has a top surface and a second bottom surface opposite to the second bottom surface and located between the first substrate and the second bottom surface; a plurality of first microstructures disposed on the light emitting surface And extending in a first direction parallel to the light incident surface; a plurality of second microstructures disposed on the second bottom surface and extending along the first direction respectively; and a plurality of third microstructures connected Between the first bottom surface and the top surface, and extending in a second direction perpendicular to the light incident surface. The light guide plate of claim 1, wherein each of the first microstructures has a first side surface and a first light guiding surface, wherein the first side surface is located at the first light guiding surface and the light incident surface And the angle between the first light guiding surface and the light emitting surface in the first substrate is greater than 0 degrees and less than or equal to 5 degrees, and each of the second microstructures has a second side surface and a second light guiding surface. The second side surface is located between the second light guiding surface and the light incident surface, and the second light guiding surface and the second bottom surface are in a range of 25 degrees to 35 degrees in a corner of the second substrate. The light guide plate of claim 1, wherein each of the third microstructures has a first connection surface, a second connection surface, a third connection surface, and a fourth connection surface, the first connection surface Connecting with the first bottom surface, the second connecting surface is connected to the top surface, the third connecting surface and the fourth connecting surface are respectively connected to the first connecting surface and the second connecting surface, and the first connecting surface is The width in the first direction is smaller than the width of the second connecting surface in the first direction. The light guide plate of claim 3, wherein the third connecting surface and the top surface of the top surface are in a range of 60 to 70 degrees, and the fourth connecting surface is The top surface of the top surface is in the range of 60 to 70 degrees. The light guide plate of claim 1, wherein the first substrate, the second substrate, the first microstructures, the second microstructures, and the third microstructures are made of the same material. The light guide plate of claim 1, wherein the light exit surface, the first bottom surface, the top surface, and the second bottom surface are parallel to each other. The light guide plate of claim 1, further comprising: a reflective layer disposed on the second microstructures and disposed on a region of the second bottom surface that is not covered by the second microstructures. A light source module includes: a light source; and a light guide plate, comprising: a first substrate; a second substrate opposite to the first substrate, the first substrate has a light emitting surface, a first bottom surface, and a light incident surface, wherein the first bottom surface is opposite to the light emitting surface and is located on the light emitting surface and the second substrate The light incident surface is connected to the light emitting surface and the first bottom surface, and the light source is disposed beside the light incident surface, the second substrate has a top surface and a second bottom surface, the top surface and the second bottom surface Oppositely located between the first substrate and the second bottom surface; a plurality of first microstructures disposed on the light-emitting surface and extending along a first direction parallel to the light-incident surface; a structure disposed on the second bottom surface and extending along the first direction; and a plurality of third microstructures connected between the first bottom surface and the top surface and respectively perpendicular to the light incident surface A second direction extends. The light source module of claim 8, wherein each of the first microstructures has a first side surface and a first light guiding surface, wherein the first side surface is located on the first light guiding surface and the light incident surface And the angle between the first light guiding surface and the light emitting surface in the first substrate is greater than 0 degrees and less than or equal to 5 degrees, and each of the second microstructures has a second side surface and a second light guiding surface The second side surface is located between the second light guiding surface and the light incident surface, and the second light guiding surface and the second bottom surface are in a range of 25 degrees to 35 degrees in a corner of the second substrate. . The light source module of claim 8, wherein each of the third microstructures has a first connection surface, a second connection surface, a third connection surface, and a fourth connection surface, the first connection The surface is connected to the first bottom surface, and the second connecting surface is The top surface is connected to the first connecting surface and the second connecting surface, and the width of the first connecting surface in the first direction is smaller than the second connecting surface The width in the first direction. The light source module of claim 10, wherein the third connecting surface and the top surface of the top surface are in a range of 60 to 70 degrees, and the fourth connecting surface The corners of the top surface in the third microstructure are in the range of 60 to 70 degrees. The light source module of claim 8, wherein the first substrate, the second substrate, the first microstructures, the second microstructures, and the third microstructures are made of the same material. The light source module of claim 8, wherein the light emitting surface, the first bottom surface, the top surface, and the second bottom surface are parallel to each other. The light source module of claim 8, wherein the light guide plate further comprises a reflective layer disposed on the second microstructures and disposed on the second bottom surface without the second micro On the area covered by the structure. The light source module of claim 8, further comprising: a diffusion sheet, wherein the first microstructures are located between the diffusion sheet and the first substrate.