Light source module and display device

Abstract

The invention provides a light source module and a display device. The light source module comprises a light guide plate and light sources. The light guide plate comprises a first light guide layer, a second light guide layer and a light-transmitting adhesive layer. The second light guide layer is bonded to the first light guide layer through the light-transmitting adhesive layer. The absolute value of the refractive index difference between any one of the first light guide layer and the second light guide layer and the light-transmitting adhesive layer is smaller than or equal to 0.02. The light source is disposed adjacent to a side of the light guide plate.

Description

Technical Field

[0001] The present invention relates to a module and a device, and more particularly to a light source module and a display device. Background Art

[0002] Although the development of light source modules and display devices has become increasingly mature, there are still some problems (such as light extraction efficiency, stress, etc.) to be improved. Summary of the Invention

[0003] The present invention provides a light source module and a display device, which help to improve at least one of the above problems.

[0004] According to an embodiment of the present invention, the light source module includes a light guide plate and a light source. The light guide plate includes a first light guide layer, a second light guide layer, and a light-transmissive adhesive layer. The second light guide layer is joined to the first light guide layer through the light-transmissive adhesive layer. The absolute value of the refractive index difference between any one of the first light guide layer and the second light guide layer and the light-transmissive adhesive layer is less than or equal to 0.02. The light source is disposed adjacent to a side surface of the light guide plate.

[0005] According to an embodiment of the present invention, the display device includes a display panel and a light source module. The light source module is disposed on the display panel and includes a light guide plate and a light source. The light guide plate includes a first light guide layer, a second light guide layer, and a light-transmissive adhesive layer. The second light guide layer is joined to the first light guide layer through the light-transmissive adhesive layer. The absolute value of the refractive index difference between any one of the first light guide layer and the second light guide layer and the light-transmissive adhesive layer is less than or equal to 0.02. The light source is disposed adjacent to a side surface of the light guide plate.

[0006] In an embodiment according to the present invention, the storage modulus of the light-transmissive adhesive layer is less than 60 kPa.

[0007] In an embodiment according to the present invention, the thickness of the light-transmissive adhesive layer is 25 μm to 75 μm.

[0008] In an embodiment according to the present invention, the material of the light-transmissive adhesive layer includes an optically transparent adhesive or an optically transparent resin.

[0009] In an embodiment according to the present invention, the thickness of the light guide plate is less than the thickness of the light source.

[0010] In an embodiment according to the present invention, a plurality of microstructures are formed on a surface of the second light guide layer away from the light-transmissive adhesive layer.

[0011] In an embodiment according to the present invention, the first light guide layer, the second light guide layer, and the light-transmissive adhesive layer have the same area.

[0012] To make the above features and advantages of the present invention more obvious and understandable, specific embodiments are given below and described in detail in conjunction with the accompanying drawings as follows. Brief Description of the Drawings

[0013] The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated into and constitute a part of this specification. The drawings illustrate embodiments of the present invention and, together with the description, are used to explain the principles of the present invention.

[0014] Figure 1 is a partial cross-sectional schematic diagram of a light source module according to an embodiment of the present disclosure;

[0015] Figure 2 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present disclosure.

[0016] Explanation of reference numerals in the drawings

[0017] 1: Light source module;

[0018] 2: Display panel;

[0019] 10: Light guide plate;

[0020] 12: Light source;

[0021] 100: First light guide layer;

[0022] 102: Second light guide layer;

[0023] 104: Transparent adhesive layer;

[0024] B: Light beam;

[0025] B’: Display light beam;

[0026] DD: Display device;

[0027] M: Microstructure;

[0028] P: Pitch;

[0029] SB: Bottom surface;

[0030] SS: Side surface;

[0031] ST: Top surface;

[0032] T10, T12, T100, T102, T104: Thickness;

[0033] X, Y, Z: Directions. Detailed implementation manners

[0034] The directional terms mentioned herein, such as "up", "down", "front", "back", "left", "right", etc., are only with reference to the directions in the accompanying drawings. Therefore, the directional terms used are for explanation and not for limiting the present invention.

[0035] In the accompanying drawings, each drawing shows the general characteristics of the methods, structures, and / or materials used in specific embodiments. However, these drawings should not be construed as defining or limiting the scope or nature covered by these embodiments. For example, for clarity, the relative dimensions, thicknesses, and positions of each film layer, region, or structure may be reduced or enlarged.

[0036] In the accompanying drawings, the same or similar elements will be denoted by the same or similar reference numerals, and the description thereof will be omitted in the specification. In addition, the features in different embodiments can be combined with each other without conflict, and simple equivalent changes and modifications made according to this specification or the claims still fall within the scope covered by the present invention.

[0037] The terms "first", "second", etc. mentioned in this specification or the claims are only used to name different elements or distinguish different embodiments or scopes, and are not used to limit the upper or lower limits of the number of elements, nor to define the manufacturing order or setting order of the elements. In addition, an element / film layer being disposed on (or above) another element / film layer can cover the case where the element / film layer is directly disposed on (or above) the other element / film layer and the two element / film layers are in direct contact; and the case where the element / film layer is indirectly disposed on (or above) the other element / film layer and there is one or more element / film layers between the two element / film layers.

[0038] Figure 1 is a partial cross-sectional schematic view of a light source module according to an embodiment of the present disclosure. Please refer to Figure 1 , the light source module 1 may include a light guide plate 10 and a light source 12. The light guide plate 10 may include a first light guide layer 100, a second light guide layer 102, and a light-transmitting adhesive layer 104. The second light guide layer 102 is joined to the first light guide layer 100 through the light-transmitting adhesive layer 104. The absolute value of the refractive index difference between any one of the first light guide layer 100 and the second light guide layer 102 and the light-transmitting adhesive layer 104 is less than or equal to 0.02. The light source 12 is disposed adjacent to the side surface SS of the light guide plate 10.

[0039] Specifically, as Figure 1As shown, the light guide plate 10 can be a composite light guide plate formed by alternately stacking multiple light guide layers (such as the first light guide layer 100 and the second light guide layer 102) and at least one light-transmitting adhesive layer (such as the light-transmitting adhesive layer 104) along the thickness direction of the light source module 1 (such as the direction Z). The materials of the multiple light guide layers (including the first light guide layer 100 and the second light guide layer 102) include, for example, plastics such as polymethyl methacrylate (PMMA) or polycarbonate (PC), but are not limited thereto. The materials of the light-transmitting adhesive layer (including the light-transmitting adhesive layer 104) include, for example, sticky and light-transmitting materials such as optical clear adhesive (OCA) or optical clear resin (OCR), but are not limited thereto.

[0040] The shape of the light guide plate 10 can be flat. Taking a rectangular flat plate as an example, the light guide plate 10 can have a top surface ST, a bottom surface SB, and four side surfaces SS. The top surface ST and the bottom surface SB are opposite to each other, and the four side surfaces SS are respectively located around the top surface ST / bottom surface SB and connect the top surface ST and the bottom surface SB. The top surface ST is, for example, the surface of the second light guide layer 102 away from the light-transmitting adhesive layer 104, the bottom surface SB is, for example, the surface of the first light guide layer 100 away from the light-transmitting adhesive layer 104, and each side surface SS is, for example, composed of the side wall surfaces of the first light guide layer 100, the light-transmitting adhesive layer 104, and the second light guide layer 102 on the same side.

[0041] The light source 12 is disposed adjacent to at least one of the multiple side surfaces SS of the light guide plate 10. Taking a single-sided light-incident light source module as an example, the light source 12 can be disposed adjacent to one side surface SS of the light guide plate 10. Taking a multi-sided light-incident light source module as an example, the light source 12 can be disposed adjacent to multiple side surfaces SS of the light guide plate 10. In some embodiments, although not shown, the light source 12 can include multiple light-emitting diodes. In Figure 1 Under the architecture of, the multiple light-emitting diodes can be arranged along the direction Y beside the side surface SS of the light guide plate 10, but are not limited thereto.

[0042] The light beam B emitted by the light source 12 can enter the light guide plate 10 through the side surface SS of the light guide plate 10, and the light beam B entering the light guide plate 10 can be transmitted in the direction away from the light source 12 (such as the direction X) in the form of total internal reflection (TIR). One of the top surface ST and the bottom surface SB of the light guide plate 10 can be formed with multiple microstructures M to break the total internal reflection so that the light beam B can exit the light guide plate 10. The multiple microstructures M can protrude or recess from one of the top surface ST and the bottom surface SB of the light guide plate 10. Taking a front light module as an example, such as Figure 1As shown, the top surface ST of the light guide plate 10 (such as the surface of the second light guide layer 102 away from the light-transmissive adhesive layer 104) may be formed with a plurality of microstructures M, so that the light beam B can exit the light guide plate 10 from the bottom surface SB of the light guide plate 10. Taking the backlight module as an example, although not shown, the bottom surface SB of the light guide plate 10 (such as the surface of the first light guide layer 100 away from the light-transmissive adhesive layer 104) may be formed with a plurality of microstructures M, so that the light beam B can exit the light guide plate 10 from the top surface ST of the light guide plate 10.

[0043] In some embodiments, the pitch P of the plurality of microstructures M may decrease in the direction away from the light source 12 (such as the direction X) to improve the light emission uniformity in the direction X, but not limited thereto. In some embodiments, although not shown, the plurality of microstructures M may be staggered in the direction Y to improve the light emission uniformity in the direction Y, but not limited thereto.

[0044] In some embodiments, the light source module 1 may be a foldable light source module or a rollable light source module. In these embodiments, the thicknesses (such as the thickness T100 and the thickness T102) of the multi-layer light guide layers (including the first light guide layer 100 and the second light guide layer 102) may be thinned to less than 400 μm (such as 100 μm or 50 μm, but not limited thereto) to facilitate folding or curling. In addition, the thickness T104 of the light-transmissive adhesive layer 104 may be 25 μm to 75 μm, that is, 25 μm ≤ T104 ≤ 75 μm, to balance the adhesion and the flexure (such as folding or curling) characteristics. The storage modulus of the light-transmissive adhesive layer 104 is, for example, less than 60 kPa to facilitate folding or curling.

[0045] The thickness T10 of the light guide plate 10 becomes thinner as the thicknesses of the multi-layer light guide layers and / or the light-transmissive adhesive layer are thinned. On the other hand, limited by the traditional packaging design or yield considerations, the thinning of the light source 12 has its limit, so that the thickness T10 of the light guide plate 10 may be less than the thickness T12 of the light source 12. When the thickness T10 of the light guide plate 10 is less than the thickness T12 of the light source 12, the thinner the thickness T10 of the light guide plate 10, the lower the light coupling efficiency, that is, the less the light beam B entering the light guide plate 10. Compared with using a single-layer thinned light guide layer, the light coupling efficiency can be improved by increasing the number of light guide layers.

[0046] Two adjacent light guide layers (including the first light guide layer 100 and the second light guide layer 102) may be fixed together via a light-transmissive adhesive layer (including the light-transmissive adhesive layer 104). The light-transmissive adhesive layer can reduce the shielding of the light beam B and can serve as a buffer layer to reduce the stress during folding or curling.

[0047] In some embodiments, such as Figure 1As shown, the multi-layer light guide layers (including the first light guide layer 100 and the second light guide layer 102) and the light-transmissive adhesive layer (including the light-transmissive adhesive layer 104) in the light guide plate 10 may have the same orthogonal projection. For example, the orthogonal projections of the first light guide layer 100, the second light guide layer 102, and the light-transmissive adhesive layer 104 on the XY plane formed by the direction X and the direction Y may be the same, so as to achieve the full adhesion of the first light guide layer 100 and the second light guide layer 102.

[0048] In the full adhesion structure, the refractive index of the light-transmissive adhesive layer 104 may match the refractive index of any one of the first light guide layer 100 and the second light guide layer 102, so as to improve the light extraction efficiency, light output brightness, and / or contrast of the light source module 1. The refractive index of the light-transmissive adhesive layer 104 matching the refractive index of any one of the first light guide layer 100 and the second light guide layer 102 means that the refractive index of the light-transmissive adhesive layer 104 is the same as or close to the refractive index of any one of the first light guide layer 100 and the second light guide layer 102. The refractive index being close means that the absolute value of the refractive index difference is less than or equal to 0.02. If the refractive index of the first light guide layer 100 is n1, the refractive index of the second light guide layer 102 is n2, and the refractive index of the light-transmissive adhesive layer 104 is n3, then |n3 - n1| ≤ 0.02 indicates that the refractive index of the light-transmissive adhesive layer 104 matches / is close to the refractive index of the first light guide layer 100, and |n3 - n2| ≤ 0.02 indicates that the refractive index of the light-transmissive adhesive layer 104 matches / is close to the refractive index of the second light guide layer 102.

[0049] In other embodiments, although not shown, the light guide plate 10 may include more light guide layers and more light-transmissive adhesive layers. For example, the light guide plate may include N light guide layers and (N - 1) light-transmissive adhesive layers alternately stacked in the direction Z, where N may be a positive integer greater than 2.

[0050] In other embodiments, although not shown, the light source module 1 may further include other elements or film layers, such as one or more optical films, but not limited thereto.

[0051] Figure 2 is a partial cross-sectional schematic diagram of a display device according to an embodiment of the present disclosure. Please refer to Figure 2 , the display device DD may include a display panel 2 and a light source module 1. The light source module 1 is disposed on the display panel 2 and may include a light guide plate 10 and a light source 12. The light guide plate 10 may include a first light guide layer 100, a second light guide layer 102, and a light-transmissive adhesive layer 104. The second light guide layer 102 is joined to the first light guide layer 100 through the light-transmissive adhesive layer 104. The absolute value of the refractive index difference between any one of the first light guide layer 100 and the second light guide layer 102 and the light-transmissive adhesive layer 104 is less than or equal to 0.02. The light source 12 is disposed adjacent to the side surface SS of the light guide plate 10.

[0052] As shown Figure 2 in FIG. 0, the light source module 1 is, for example, a side-light type front light module. The light beam B from the light source 12 enters the light guide plate 10 through the side surface SS of the light guide plate 10, and the light beam B is transmitted in the direction away from the light source 12 (such as the direction X) in a total reflection manner. A plurality of microstructures M located on the top surface ST of the light guide plate 10 break the total reflection, so that the light beam B exits the light guide plate 10 from the bottom surface SB of the light guide plate 10 and is transmitted toward the display panel 2 located below the light source module 1. The display side of the display panel 2 (i.e., the side where the display panel 2 provides an image) faces the light source module 1. The light beam B incident on the display panel 2 is converted by the display panel 2 into a display light beam B' (for example, a light beam with grayscale and / or color information). The display light beam B' is reflected back to the light source module 1 by the display panel 2 and then penetrates the light source module 1 and exits from the display device DD. By using a light-transmissive adhesive layer 104 to bond the first light guide layer 100 and the second light guide layer 102, the shielding of the display light beam B' by the light-transmissive adhesive layer 104 can be reduced. The display panel 2 may include a reflective display panel (such as an electrophoretic display panel, but not limited thereto) or a partially transmissive and partially reflective display panel, but not limited thereto.

[0053] When the material of the substrate (not shown) in the display panel 2 is different from the material of the light guide layers (such as the first light guide layer 100 and the second light guide layer 102) in the light guide plate 10, for example, when the substrate in the display panel 2 is a glass substrate and the light guide layers in the light guide plate 10 are plastic light guide layers, warping problems caused by mismatched thermal expansion coefficients are likely to occur. Through the design of multiple light guide layers and at least one light-transmissive adhesive layer, the light-transmissive adhesive layer can serve as a buffer layer to reduce the stress during warping. In addition, when the display device DD is a foldable display device or a rollable display device, the light-transmissive adhesive layer can also serve as a buffer layer to reduce the stress during folding or rolling.

[0054] In summary, in the embodiments of the present invention, stress can be reduced through the design of multiple light guide layers and at least one light-transmissive adhesive layer, and the light extraction efficiency, light output brightness, and / or contrast ratio can be improved through the design of the refractive index matching between the light guide layer and the light-transmissive adhesive layer.

[0055] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light source module, characterized in that, Comprising: A light guide plate, comprising a first light guide layer, a second light guide layer, and a light-transmitting adhesive layer, wherein the second light guide layer is joined to the first light guide layer through the light-transmitting adhesive layer, and the absolute value of the refractive index difference between any one of the first light guide layer and the second light guide layer and the light-transmitting adhesive layer is less than or equal to 0.02; and A light source, disposed adjacent to a side surface of the light guide plate.

2. The light source module according to claim 1, characterized in that, The storage modulus of the light-transmitting adhesive layer is less than 60 kPa.

3. The light source module according to claim 1, wherein The thickness of the light-transmitting adhesive layer is 25 μm to 75 μm.

4. The light source module according to claim 1, wherein The material of the light-transmitting adhesive layer comprises an optically transparent adhesive or an optically transparent resin.

5. The light source module according to claim 1, characterized in that, The thickness of the light guide plate is less than the thickness of the light source.

6. The light source module according to claim 1, wherein A plurality of microstructures are formed on a surface of the second light guide layer away from the light-transmitting adhesive layer.

7. The light source module according to claim 1, wherein The first light guide layer, the second light guide layer, and the light-transmitting adhesive layer have the same orthogonal projection.

8. A display device, characterized in that, Comprising: A display panel; And A light source module, disposed on the display panel and comprising: A light guide plate, comprising a first light guide layer, a second light guide layer, and a light-transmitting adhesive layer, wherein the second light guide layer is joined to the first light guide layer through the light-transmitting adhesive layer, and the absolute value of the refractive index difference between any one of the first light guide layer and the second light guide layer and the light-transmitting adhesive layer is less than or equal to 0.02; and A light source, disposed adjacent to a side surface of the light guide plate.

9. The display device according to claim 8, wherein The storage modulus of the light-transmitting adhesive layer is less than 60 kPa.

10. The display device according to claim 8, wherein, The thickness of the light-transmitting adhesive layer is 25 μm to 75 μm.

11. The display device according to claim 8, wherein The material of the light-transmitting adhesive layer comprises an optically transparent adhesive or an optically transparent resin.

12. The display device according to claim 8, wherein, The thickness of the light guide plate is less than the thickness of the light source.

13. The display device according to claim 8, characterized in that, A plurality of microstructures are formed on a surface of the second light guide layer away from the light-transmitting adhesive layer.

14. The display device according to claim 8, wherein The first light guide layer, the second light guide layer, and the light-transmitting adhesive layer have the same orthogonal projection.

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