TWI678580B - Backlight unit - Google Patents

Abstract

A backlight unit includes a light source module, an adhesive layer, and a protective film. The light source module has a central area and a peripheral area surrounding the central area. The adhesive layer is adhered to the peripheral area of the light source module, and the protective film covers the light source module. The protective film is adhered to the light source module through an adhesive layer. The protective film has a plurality of cut patterns. These cut patterns are separated from each other, and on a projection plane parallel to the protective film, these cut patterns do not overlap with the peripheral region.

Description

   Backlight unit   

The present disclosure relates to a backlight unit, and more particularly to a backlight unit having a protective film.

In order to avoid the risk that the surface of the optical film on the backlight unit will be damaged during transportation or storage, the conventional technology will first set a protective film on the surface of the optical film of the backlight unit. When the backlight unit needs to be processed , And then remove the protective film.

However, because the material of the protective film is polyethylene terephthalate (PET), it has a certain degree of stiffness. And the stiffness will cause the protective film to return to flatness (inertia) immediately after tearing off. Therefore, when the protective film is torn off the surface of the backlight unit, the protective film will have a certain degree of bending force value. When the protective film is just detached, this bending force value will instantly act on the corners of the protective film, and it will be scratched on the protective film. Scratches on the optical film of the backlight unit.

One of the purposes of the backlight unit disclosed herein is to improve the manufacturing yield of the backlight unit by having a protective film capable of releasing stress.

One of the purposes of the backlight unit of the present disclosure is to prevent scratches of the optical film.

An embodiment of the present disclosure includes a backlight unit. The backlight unit includes a light source module, an adhesive layer, and a protective film. The light source module has a central area and a peripheral area surrounding the central area. An adhesive layer is adhered to the peripheral area of the light source module. A protective film covers the light source module. The protective film is adhered to the light source module through an adhesive layer. The protective film has a plurality of cut patterns. These cut patterns are separated from each other, and on a projection plane parallel to the protective film, these cut patterns do not overlap with the peripheral region.

Based on the above, the backlight unit of the embodiment of the present disclosure can effectively release the stress by setting the cutout pattern on the protective film, thereby preventing the protective film from scratching the surface of the light source module when it is detached from the light source module. In this way, the manufacturing yield of the backlight unit can be effectively improved.

100‧‧‧ backlight unit

110‧‧‧light source module

111, 112, 113‧‧‧ Optical diaphragm

114‧‧‧light guide

115‧‧‧ frame

120‧‧‧ Adhesive layer

130, 530, 630‧‧‧ protective film

131,531,631‧‧‧‧cut pattern

133‧‧‧ protrusion

a, b, L, x, y‧‧‧ length

AD1‧‧‧first arrangement direction

AD2‧‧‧Second arrangement direction

CA‧‧‧Central District

CP1‧‧‧First Notch Unit

CP2‧‧‧Second Notch Unit

CR1‧‧‧First Corner

CR2‧‧‧Second Corner

DL‧‧‧Diagonal

F‧‧‧ bending force

ED1‧‧‧First extension direction

ED2‧‧‧Second extension direction

LS‧‧‧long side

P‧‧‧force action point

PL‧‧‧ projection plane

PA‧‧‧Peripheral area

PS1‧‧‧The first pattern segment

S‧‧‧Pitch

SS‧‧‧Short side

ST‧‧‧ connecting section

S1‧‧‧First surface

S2‧‧‧Second surface

θ1‧‧‧First angle

θ2‧‧‧ second angle

θ3‧‧‧ third angle

β1, β2, β3, β4‧‧‧ angle

1A-1A‧‧‧ hatching

Read the following detailed description and the corresponding drawings to understand the various aspects of this disclosure. It should be noted that according to standard practice in the industry, multiple features are not drawn to scale. In fact, the dimensions of multiple features can be arbitrarily increased or decreased to facilitate clarity of discussion.

FIG. 1A is a cross-sectional view of a backlight unit according to an embodiment of the disclosure.

FIG. 1B is an exploded view of a backlight unit according to an embodiment of the disclosure.

Fig. 2 is a front view of the protective film of Fig. 1A.

FIG. 3A is a partial front view of a protective film according to an embodiment of the disclosure.

FIG. 3B is a side view of the protective film according to an embodiment of the present disclosure when it is peeled off.

4A to 4B are front views of a protective film according to different embodiments of the present disclosure.

FIG. 5 is a front view of a protective film according to another embodiment of the disclosure.

FIG. 6 is a front view of a protective film according to another embodiment of the disclosure.

FIG. 1A is a cross-sectional view of a backlight unit 100 according to an embodiment of the present disclosure, and FIG. 1B is an exploded view of the backlight unit 100 according to an embodiment of the present disclosure, wherein FIG. 1A is a section line along FIG. 1B 1A-1A sectional view. Fig. 2 is a front view of the protective film 130 of Fig. 1A. As shown in FIGS. 1A to 2, the backlight unit 100 of this embodiment includes a light source module 110, an adhesive layer 120, and a protective film 130. Specifically, as shown in FIG. 1A to FIG. 1B, in this embodiment, the light source module 110 includes, for example, at least one optical film, a light guide plate 114, a light source assembly 116, and an outer frame 115. In order to provide a uniform area light source to the display panel. For example, in this embodiment, three optical films 111, 112, and 113 are taken as an example. The optical films 111 and 112 may be cymbals and the optical film 113 may be a diffusion film. This is limited. The outer frame 115 may be, for example, a plastic frame, and a reflective sheet is attached to the bottom of the plastic frame through an adhesive member, but is not limited thereto. For example, the light source module 110 may further include a casing (not shown) to cover the plastic frame and the plastic frame. Reflective sheet, adjustable according to demand. The light source module 116 includes, for example, a light source and a circuit substrate. In this embodiment, a side-type light source module is taken as an example, but it is not limited to this. In practice, a direct-type light source module can also be used, which can be adjusted according to actual needs.

As shown in FIG. 1A to FIG. 1B, in this embodiment, the light source module 110 has a central area CA and a peripheral area PA surrounding the central area CA. The adhesive layer 120 is adhered to the peripheral area PA of the light source module 110. Specifically, as shown in FIG. 1A to FIG. 1B, in this embodiment, the protective film 130 covers the light source module 110 and is adhered to the light source module 110 through the adhesive layer 120. In one embodiment, after the protective film 130 is removed, the display panel can be adhered to the light source module 110 through the adhesive layer 120, and the central area CA of the light source module 110 can correspond to the visual area of the display panel (i.e., the Active Area). ) To provide uniform light to the display panel.

In addition, as shown in FIGS. 1A to 1B, the protective film 130 is connected to the light source module 110 through the adhesive layer 120. In one embodiment, the protective film 130 is connected to at least one optical film 111 of the light source module 110 through the adhesive layer 120, for example. In one embodiment, the adhesive layer 120 is disposed on at least the top surface of the outer frame 115, for example. Specifically, when the backlight unit 100 has a narrow frame design, the adhesive layer 120 is adhered to the top surface of the outer frame 115 and the edge of the uppermost optical film 111 to provide a sufficient attachment area, thereby effectively fixing. Protective film 130. However, this disclosure is not limited to this. When the optical film 111 has ears, or is relatively difficult to slide, or the edge of the outer frame 115 is large, the adhesive layer 120 may be provided only on the top surface of the outer frame 115, which can provide a sufficient attachment area.

Further, as shown in FIG. 2, in this embodiment, the protective film 130 has a plurality of cutout patterns 131, and these cutout patterns 131 are separated from each other. In one embodiment, each of the cutout patterns 131 can pass through the protective film 130, that is, the protective film 130 can have a first surface S1 and a second surface S2 opposite to each other, and each of the cutout patterns 131 can be a through hole and The first surface S1 and the second surface S2 are penetrated. Each of the cutout patterns 131 can penetrate the protective film 130, which can help release stress more effectively, and thus avoid the protective film 130 from scratching the surface of the light source module 110 when it is detached from the light source module 110. In addition, in this embodiment, the production of the cut pattern 131 penetrating the protective film 130 may be integrated into the manufacturing process of the adhesive layer 120 and the protective film 130 of the backlight unit 100. For example, in the process of performing the secondary punching (outer edge punching) and waste disposal of the adhesive layer 120, the adhesive layer 120 and the protective film 130 thereon can be cut at the same time to form the exposed adhesive at the same time. The layer 120 and the cutout pattern 131 are out of shape. In other words, in this embodiment, the manufacturing process of the cutout pattern 131 can be integrated into the secondary punching and waste disposal process of the adhesive layer 120. Specifically, after the above steps are performed, the edge of the protective film 130 and the edge of the adhesive layer 120 may be aligned (as shown in FIG. 1A).

In this way, in the process of forming the adhesive layer 120 and the protective film 130, a plurality of cutout patterns 131 of the protective film 130 can also be formed, and since the process of forming the cutout patterns 131 can be integrated into the original process of the backlight unit 100, No additional production costs.

Further, please refer to FIG. 2 again. In this embodiment, for example, the plurality of cutout patterns 131 may form a plurality of first cutout units CP1, and the first cutout units CP1 may be parallel to each other, and respectively along a first An extension direction ED1 extends, and the first cutout units CP1 are arranged along a first arrangement direction AD1 substantially perpendicular to the first extension direction ED1. As shown in FIG. 2, in this embodiment, each of the first cutout units CP1 is, for example, formed by arranging a plurality of first pattern segments PS1 along the first extending direction ED1, and the outline of each first pattern segment PS1 is, for example, Straight. As shown in FIG. 2, in this embodiment, the front end of a certain first pattern segment PS1 can be connected to the rear end of another adjacent first pattern segment PS1; in other words, in this embodiment, the On a projection plane PL where the film 130 is parallel, the first notch unit CP1 can be combined into a discontinuous dotted pattern, for example, by a plurality of first pattern segments PS1, but the disclosure is not limited thereto.

For example, in this embodiment, the width of the cut pattern 131 is substantially about 30 micrometers. In this way, since the particle size of foreign materials (such as dust) is generally about 150 microns, generally, the foreign materials will not enter the backlight unit 100 through the cutout pattern 131, and the protective film 130 can still prevent the foreign materials from entering and avoid damage. Which component. It should be noted that the above parameter ranges are only for illustrative purposes, and are not intended to limit the present disclosure.

In addition, as shown in FIG. 2, in this embodiment, the cutout patterns 131 are separated from each other, and on a projection plane PL parallel to the protective film 130, the cutout patterns 131 do not overlap with the peripheral area PA. In detail, the projection plane PL is a parallel protective film 130, and each of these cutout patterns 131 is vertically projected onto the projection plane PL without overlapping the peripheral area PA. In other words, in this embodiment, the cutout patterns 131 are not connected to each other, nor extend to the peripheral area PA where the adhesive layer 120 of the light source module 110 is located.

Specifically, in order to meet the requirements of a narrow frame, the cutout pattern 131 cannot be completely disposed in the peripheral area PA. However, if the cutout pattern 131 crosses the boundary between the central area CA of the light source module 110 and the peripheral area PA where the adhesive layer 120 is located, the intersection may have a height difference caused by the thickness of the adhesive layer 120, which may cause a cutout. The width of the pattern 131 is stretched, and there is a risk that foreign matter may enter. Therefore, in this embodiment, the protective film 130 arranges the cutout pattern 131 at the center of the light source module 110 by making the cutout patterns 131 not overlap with the peripheral area PA on the projection plane PL parallel to the protective film 130. District CA. In addition, since the process of the cut pattern 131 of the protective film 130 in this embodiment can be integrated into the die-cutting process of the adhesive layer 120, there is no relative displacement generated when it is attached to the backlight unit 100, and the cut pattern 131 can avoid the possibility of overlapping with the peripheral area PA where the adhesive layer 120 is located, thereby avoiding the risk of foreign objects entering the backlight unit 100.

In addition, it should be noted that, because the corners of the protective film 130 have the configuration of the cutout pattern 131, the stiffness of the corners of the protective film 130 is reduced, and the protective film 130 can be prevented from being separated from the light source module 110. The optical film 111 of the light source module 110 is damaged. This will be further explained with reference to Figures 3A to 3B.

FIG. 3A is a partial front view of the protective film 130 according to an embodiment of the disclosure. FIG. 3B is a side view when the protective film 130 is peeled off according to an embodiment of the disclosure. As shown in FIG. 3A, in this embodiment, each of the first pattern segments PS1 has a length L, and adjacent first pattern segments PS1 have, for example, a distance S, and the length L may be greater than the distance S. . The diagonal lines DL of the first pattern segments PS1 along the first extending direction ED1 and the protective film 130 may have a first included angle θ1 , and the angle of the first included angle θ1 is greater than zero. For example, in this embodiment, a pair of diagonal lines DL of the first extending direction ED1 and the protective film 130 may be substantially perpendicular to each other, that is, the first included angle θ1 is substantially 90 degrees, but this disclosure does not take this as an example. Limited. It should be noted that the above parameter ranges are only for illustrative purposes, and are not intended to limit the present disclosure.

In this way, as shown in FIG. 3A and FIG. 3B, when the protective film 130 is detached from the light source module 110, the first slit unit CP1 can be arranged along the first arrangement direction AD1 perpendicular to the first extension directions ED1. As a result, the main force application point P of the bending force F on the protective film 130 will be moved upward, and direct contact with the surface of the light source module 110 can be avoided. In addition, the bending force F is weakened by the first notch units CP1 layer by layer, so that the stiffness of the protective film 130 is greatly reduced, and the tendency to restore flatness (that is, inertia) is reduced. In this way, when the protective film 130 is detached from the light source module 110, the probability of damaging the uppermost optical film 111 of the light source module 110 is reduced.

Specifically, in this embodiment, when the application direction of the bending force F and the first extension direction ED1 where the first notch unit CP1 extends are substantially close to 90 degrees, the first notch unit CP1 weakens the bending force. The effect of F is the best. Therefore, when the user tears off the protective film 130 from the light source module 110 through a protruding portion 133 of the protective film 130 (shown in FIGS. 4A and 4B), the first notch unit The geometric configuration of the first extension direction ED1 of CP1 and the protruding portion 133 of the protective film 130 will conform to a specific mathematical formula so that the angle between the direction of application of the bending force F and the first extension direction ED1 is substantially close to 90 degrees. . This will be explained further with reference to Figures 4A to 4B.

4A to 4B are front views of the protective film 130 according to different embodiments of the present disclosure. Specifically, as shown in FIG. 4A, in this embodiment, the protective film 130 has, for example, a first corner CR1 and a second corner CR2, and the first corner CR1 and the second corner CR2 may be respectively located on the protective film 130. On the opposite ends of the pair of diagonal lines DL, the protective film 130 may further include a protruding portion 133, the protruding portion 133 may protrude from the second corner CR2, and the first notch units CP1 may be located at the first corner CR1. It should be noted that, in order to clearly express the corresponding relationship, the notch pattern is omitted in FIGS. 4A and 4B.

On the other hand, as shown in FIG. 4A, the protective film 130 has, for example, a pair of long sides LS and a pair of short sides SS, and each of the long sides LS is adjacent to these short sides SS, respectively, where the long side LS and the short side SS are substantially Vertically, the first corner CR1 may be located on an end where the long side LS and the short side SS of the protective film 130 intersect. Further, in the present embodiment, the short side SS of the protective film 130 has a length x, and the long side LS of the protective film 130 has a length y. For example, as shown in FIG. 4A, in this embodiment, the protruding portion 133 protrudes from one of the short sides SS of the protective film 130, and the outline of the protruding portion 133 has a length a and a length b, where The length b is the length of one side of the protrusion 133 substantially parallel to the long side LS (or substantially perpendicular to the short side SS), and the length a is the protrusion 133 is substantially perpendicular to the long side LS (or substantially parallel) For short side (SS). In addition, as shown in FIG. 4A, the shortest distance from the edge of the protruding portion 133 to the long side LS away from the second corner CR2 may be a distance s.

Further, as shown in FIG. 3A and FIG. 4A, in this embodiment, the first extending direction ED1 of the first slit unit CP1 and the long side LS of the protective film 130 have a second included angle θ 2, The second included angle θ 2 ranges between a first angle β1 and a second angle β2 . Therefore, when the first angle β1 and the second angle β2 meet the following relationship: β1 = 90 ° -arc tan [s / (y + b)] , and β2 = 90 ° -arc tan [(s + a) / y ] , The angle between the direction of application of the bending force F and the first extension direction ED1 of the first notch unit CP1 is substantially close to 90 degrees, and can have a better effect of weakening the bending force F, but this disclosure does not This is the limit. In another embodiment, the protruding portion 133 may also protrude from one of the long sides LS of the protective film 130. At this time, the first extending direction ED1 of the first slit unit CP1 and the short side SS of the light source module 110. Would fit into another relationship.

For example, as shown in FIG. 4B, when the protruding portion 133 protrudes from one of the long sides LS of the protective film 130, the length b at this time is the length of the protruding portion 133 that is substantially perpendicular to one side of the short side SS. The length, the length a, is the length of the convex portion 133 substantially parallel to one side of the short side SS. As shown in FIG. 4B, the shortest distance from the edge of the protruding portion 133 to the short side SS far from the second corner CR2 is the distance s. Further, as shown in FIGS. 3A and 4B, the first extending direction ED1 and the short side SS of the light source module 110 at this time have a third included angle θ 3, and the range of the third included angle θ 3 is between one Between the third angle β3 and a fourth angle β4 , wherein the third angle β3 and the fourth angle β4 conform to the following relationship: β3 = 90 ° -arc tan [s / (x + a)] and β4 = 90 °- arc tan [(s + b) / x] . Thus, under this arrangement relationship, when the protective film 130 is torn from the light source module 110 by the protruding portion 133, the angle between the direction of the bending force F and the first extension direction ED1 of the first slit unit CP1 It is substantially close to 90 degrees, and can have a better effect of weakening the bending force F.

FIG. 5 is a front view of a protective film 530 according to another embodiment of the disclosure. Please refer to FIG. 5. The protective film 530 in FIG. 5 is similar to the protective film 130 in FIG. 2, and the differences are as follows. As shown in FIG. 5, in this embodiment, the outline of each of the first pattern segments PS1 of the cutout pattern 531 is curved, and the curved outline protrudes toward the first corner CR1 of the protective film 530. However, it is not limited to this. In another embodiment, the contour of each first pattern segment PS1 is curved, and the curved contour is concave toward the first corner CR1 (not shown) of the protective film 530.

Further, as shown in FIG. 5, in this embodiment, the first pattern segments PS1 of each of the first notch units CP1 are also arranged along the first extending direction ED1, and a certain first pattern segment PS1 The front end of the first continuous pattern is connected to the rear end of the adjacent first pattern segment PS1. In other words, in this embodiment, on the projection plane PL parallel to the protective film 530, the first notch unit CP1 is composed of a plurality of first patterns. The segments PS1 are combined to form a discontinuous wave pattern, but this disclosure is not limited thereto.

Thus, in this embodiment, the backlight unit 100 can also effectively release the stress by providing the cutout pattern 531 on the protective film 530, thereby preventing the protective film 530 from scratching the light source module 110 when detached from the light source module 110. s surface. In this way, the manufacturing yield of the backlight unit 100 can be effectively improved.

FIG. 6 is a front view of a protective film 630 according to another embodiment of the disclosure. Please refer to FIG. 6. The protective film 630 in FIG. 6 is similar to the protective film 130 in FIG. 2, and the differences are as follows. As shown in FIG. 6, in this embodiment, the cutout pattern 631 may further include forming a plurality of second cutout units CP2. These second cutout units CP2 may be parallel to each other and may extend along a second extension direction ED2, respectively. And the second cutout units CP2 may be arranged along a second arrangement direction AD2 substantially perpendicular to the second extension direction ED2, and the first extension direction ED1 is not parallel to the second extension direction ED2.

For example, as shown in FIG. 6, in this embodiment, the first extending direction ED1 of the first slit unit CP1 is, for example, substantially parallel to one of the long side LS and the short side SS of the protective film 630. The second extending direction ED2 of the two-notch unit CP2 is, for example, substantially parallel to the other of the long side LS and the short side SS of the protective film 630. In one embodiment, the long side LS and the short side SS of the protective film 630 may be substantially perpendicular. In addition, as shown in FIG. 6, in this embodiment, the protective film 630 has a first corner CR1, and the first corner CR1 is located at an end where the long side LS and the short side SS of the protective film 630 intersect. The first corner CR1 has, for example, a connecting segment ST in a direction away from the first corner CR1, and the first notch units CP1 and the second notch units CP2 are connected by the connecting segment ST. In the present embodiment, the connection segment ST extends substantially along, for example, the direction of the diagonal line DL, but is not limited thereto.

In this way, when the protective film 630 is torn away from the light source module 110, the bending force on the protective film 630 is weakened by the first notch unit CP1 and the second notch unit CP2 layer by layer, so that the stiffness of the protective film 630 is large In order to reduce, the tendency to return to flattening (ie, inertia) is weakened. In addition, by the presence of the connecting segment ST, it is also possible to prevent the protective film 630 from being broken when it is peeled off. In this way, when the protective film 630 is detached from the light source module 110, the optical film 111 of the backlight unit 100 can be prevented from being damaged.

In summary, the backlight unit according to the embodiment of the present disclosure can effectively release the stress by setting the cutout pattern on the protective film, thereby preventing the protective film from scratching the surface of the light source module when it is detached from the light source module. In this way, the manufacturing yield of the backlight unit can be effectively improved.

Claims (16)

A backlight unit includes: a light source module having a central area and a peripheral area surrounding the central area; an adhesive layer adhered to the peripheral area of the light source module; and a protective film covering the light source module, The protective film is adhered to the light source module through the adhesive layer, wherein the protective film has a plurality of cutout patterns, the cutout patterns are separated from each other, and the cutout patterns are on a projection plane parallel to the protective film. The peripheral regions do not overlap, and each of the cut patterns runs through the protective film. The backlight unit according to item 1 of the scope of patent application, wherein the cutout patterns form a plurality of first cutout units, the first cutout units are parallel to each other, and each extends along a first extension direction, and the The first notch units are arranged along a first alignment direction substantially perpendicular to the first extension direction. The backlight unit according to item 2 of the scope of patent application, wherein each of the first cutout units is formed by arranging a plurality of first pattern segments along the first extending direction, and the outline of each of the first pattern segments is linear . According to the backlight unit described in item 3 of the scope of patent application, each of the first pattern segments has a length, and there is a gap between the adjacent first pattern segments, and the length is greater than the gap. The backlight unit according to item 2 of the scope of patent application, wherein each of the first cutout units is formed by arranging a plurality of first pattern segments along the first extending direction, and the outline of each of the first pattern segments is curved. . The backlight unit according to item 2 of the patent application, wherein a diagonal line between the first extending direction and the protective film has a first included angle, and the angle of the first included angle is greater than zero. The backlight unit according to item 6 of the application, wherein the first extension direction and the diagonal line of the protective film are substantially perpendicular to each other. The backlight unit according to item 6 of the patent application scope, wherein the protective film has a first corner and a second corner, and the first corner and the second corner are respectively located opposite to the diagonal of the protective film. On the end, the protective film further includes a protruding portion protruding from the second corner, and the first cutout units are located at the first corner. The backlight unit according to item 8 of the scope of patent application, wherein the protective film has a pair of long sides and a pair of short sides, and each of the long sides is adjacent to the short sides, and when the protruding portion protrudes from the protective film In one of the short sides, the first extending direction and the long side of the protective film have a second included angle, and the range of the second included angle is between a first angle β1 and a second angle β2 , wherein the The first angle β1 and the second angle β2 conform to the following relationship: β1 = 90 ° -arc tan [s / (y + b)] β2 = 90 ° -arc tan [(s + a) / y] where y is The length of the long side of the protective film, b is the length of the side of the protrusion substantially parallel to the long side, a is the length of the side of the protrusion substantially perpendicular to the long side, and s is the protrusion The shortest distance from the edge of the exit to the long side far from the second corner. The backlight unit according to item 8 of the scope of patent application, wherein the protective film has a pair of long sides and a pair of short sides, and each of the long sides is adjacent to the short sides, and when the protruding portion protrudes from the protective film In one of the long sides, the first extending direction and the short side of the protective film have a third included angle, and the range of the third included angle is between a third angle β3 and a fourth angle β4 , where the The third angle β3 and the fourth angle β4 conform to the following relationship: β3 = 90 ° -arc tan [s / (x + a)] β4 = 90 ° -arc tan [(s + b) / x] where x is The length of the short side of the protective film, b is the length of the side of the protruding portion substantially perpendicular to the short side, a is the length of the side of the protruding portion substantially parallel to the short side, and s is the protrusion The shortest distance from the edge of the exit to the short side far from the second corner. The backlight unit according to item 2 of the scope of patent application, wherein the cutout patterns further form a plurality of second cutout units, the second cutout units are parallel to each other, and extend along a second extension direction, respectively, and the The two notch units are arranged along a second arrangement direction substantially perpendicular to the second extension direction, wherein the first extension direction is not parallel to the second extension direction. The backlight unit according to item 11 of the scope of patent application, wherein the protective film has an adjacent long side and a short side, wherein one of the long side and the short side is substantially parallel to the first extending direction, And the other of the long side and the short side is substantially parallel to the second extending direction. The backlight unit according to item 12 of the application, wherein the long side and the short side of the protective film are substantially vertical. The backlight unit according to item 12 of the patent application scope, wherein the protective film has a first corner, and the first corner is located on an end where the long side and the short side of the protective film intersect, and the protective film is formed from the first corner. A corner portion has a connection section in a direction away from the first corner, and the first cutout units and the second cutout units are connected by the connection section. The backlight unit according to item 1 of the application, wherein an edge of the protective film is aligned with an edge of the adhesive layer. The backlight unit according to item 1 of the patent application scope, wherein the light source module includes at least one optical film, and the protective film is connected to the at least one optical film of the light source module through the adhesive layer.