TWI475300B - Backlight module and applications thereof - Google Patents

Description

Backlight module and its application

The invention relates to a backlight module and an application structure thereof, and in particular to a backlight module having a narrow frame structure and an application structure thereof.

With the vigorous development of the optoelectronic industry, liquid crystal display (LCD) is widely used in television (TV), monitor, notebook (NB), personal digital assistant (personal digital) Assistant; PDA) and electronic devices such as cell phones. However, a liquid crystal display is a non-self-illuminating flat panel display that requires an external backlight or a side light source to provide illumination. Therefore, in the liquid crystal display, a backlight module is used as a light source, and the high brightness and high uniformity illumination of the backlight module enables the liquid crystal display to efficiently display a high-quality image.

Conventional backlight modules typically include a light source, a backing plate, an optical plate, and an optical film. Wherein, the light source and the optical plate are placed in the back plate; and the optical film is laid flat on the optical plate, and the mounting ear of the optical film edge is passed through the positioning pin or the back plate folding wall. The way to fix it. However, since the thermal expansion space must be reserved between the optical film and the back plate, the optical film may affect the image quality due to the warpage of the extrusion. In addition, in order to prevent the hanger from being torn due to the expansion of the optical film, a certain width must be left at the mounting ear of the pin or the back panel. Therefore, the backlight module is used to hide the border of the non-visible area, and the available space cannot be effectively reduced, which does not meet the current design requirements for the small-frame backlight module.

Therefore, there is a need to provide a novel backlight module that can effectively reduce the optical film. The size of the positioning structure of the sheet is to solve the problem that the frame size of the conventional backlight module cannot be effectively reduced, and at the same time, the display quality of the liquid crystal display is improved.

In view of this, an aspect of the present invention provides a backlight module including: a housing, an optical plate, a light source, a reflective sheet, and a first optical film. The optical plate is located in the housing and has a light emitting surface, a first side connected to the light emitting surface, and a second side opposite to the first side. The light source is disposed between the housing and the optical plate. The reflective sheet is located between the housing and the optical plate and faces the opposite side of the light exiting surface. The first optical film, facing the light exit surface, has a first extension extending between the housing and the first side.

In an embodiment of the invention, the extension is adhered to the first side by a double-sided tape or a single-sided tape.

In an embodiment of the invention, the backlight module further includes a side plate fixed to the first side, and has a reflecting surface facing the first side. In an embodiment of the invention, the coverage of the single-sided tape exceeds the first extension, and the adhesive side of the single-sided tape faces the side panel.

In an embodiment of the invention, the coverage of the single-sided tape exceeds the first extension, and the adhesive surface of the single-sided tape is a reflective surface.

In an embodiment of the invention, the extension of the first extension exceeds one-half of the thickness of the optical plate.

In an embodiment of the invention, the light incident surface of the optical plate is located on the opposite side of the first side.

In an embodiment of the invention, the light incident surface of the optical plate is located on the opposite side of the light emitting surface, and the light source is located between the optical plate and the reflective sheet.

In an embodiment of the invention, the backlight module further includes a second optical film The sheet, located between the first optical film and the light exiting surface, has a second extension extending between the housing and the first side and not overlapping the first extension.

In an embodiment of the invention, the first optical film further has a third extension extending between the housing and a third side of the optical plate.

In an embodiment of the invention, the first extension has an opening.

Another aspect of the present invention is to provide a display element including: a backlight module and a display panel. The backlight module includes a housing, an optical plate, a light source, a reflective sheet, and a first optical film. The optical plate is located in the housing and has a light emitting surface, a first side connected to the light emitting surface, and a second side opposite to the first side. The light source is disposed between the housing and the optical plate. The reflective sheet is located between the housing and the optical plate and faces the opposite side of the light exiting surface. The first optical film faces the light exit surface and has a first extension extending between the housing and the first side. The display panel is disposed on one side of the light emitting surface of the first optical film.

In an embodiment of the invention, the extension is adhered to the first side by a double-sided tape.

In an embodiment of the invention, the extension is attached to the first side by a single-sided tape.

In an embodiment of the invention, the backlight module further includes a side plate fixed to the first side, and the side plate has a reflecting surface facing the first side. In an embodiment of the invention, the coverage of the single-sided tape exceeds the first extension, and the adhesive side of the single-sided tape faces the side panel.

In an embodiment of the invention, the coverage of the single-sided tape exceeds the first extension, and the adhesive surface of the single-sided tape is a reflective surface.

In an embodiment of the invention, the extension of the first extension exceeds one-half of the thickness of the optical plate.

In an embodiment of the invention, the display element further comprises a light source adjacent to On the second side.

In an embodiment of the invention, the display element further includes a light source between the optical plate and the reflective sheet.

In an embodiment of the invention, the display element further includes a second optical film between the first optical film and the light exiting surface, the second optical film has a second extending portion extending from the housing and the first Between the sides, and not overlapping the first extension.

In an embodiment of the invention, the first optical film further has a third extension extending between the housing and the third side of the optical plate.

In an embodiment of the invention, the first extension has an opening.

According to the above, an embodiment of the present invention provides a backlight module and an application device thereof, wherein the backlight module includes an optical film facing the light emitting surface of the backlight module, and the edge of the optical film has an extension portion extending from the optical film Between the back plate of the backlight module and the side of the optical plate for carrying the optical film; and by attaching the tape to the extension, the optical film can be fixed on the side of the optical plate.

Because of the space between the back plate and the side of the optical plate, a thermal expansion space is reserved, and the thickness of the optical film and the tape is relatively thin. Therefore, the extension extending between the back plate and the side of the optical plate is fixed by tape without additionally increasing the frame size. Not only has the technical advantage of reducing the width of the frame, but also meets the design requirements of the current facing small frame backlight module. Moreover, due to the expansion coefficient of the optical plate, it is generally larger than the expansion coefficient of the optical film. If the optical film is extended and fixed between the back plate and the side of the optical plate, the optical film will expand with the optical plate having a large expansion coefficient, and be stretched synchronously to be more flat. It does not cause the optical film to be insufficiently reserved due to the expansion space, but is subject to the warpage of the back plate or the tearing of the hanging ear. Thereby, the problem of uneven brightness of the image caused by the film waving of the optical plate can be improved, which helps to improve the light uniformity of the backlight module and enhance the display. Display quality.

The present invention provides a backlight module having a narrow bezel structure to solve the problem that the frame size of the conventional backlight module cannot be effectively reduced. The above and other objects, features and advantages of the present invention will become more apparent and understood. And in conjunction with the drawings, a detailed description will be given below.

1A and FIG. 1B, FIG. 1A is a cross-sectional view showing the structure of an edge-lit backlight module 100 having a narrow bezel structure according to an embodiment of the invention. FIG. 1B is a partial perspective structural view of the backlight module 100 according to FIG. 1A . 1A is generally depicted along the tangent S of FIG. 1B. For the sake of clarity, FIG. 1B does not show all the components of the backlight module 100, but some of the components are not shown.

The backlight module 100 includes a housing 101, an optical plate 102, a reflective sheet 103, a first optical film 104, and a light source 105. The casing 101 has a bottom surface 101a and a vertical wall 101b surrounding the bottom surface 101a. In this embodiment, the housing 101 is preferably a back iron frame of the backlight module 100.

The optical plate 102 is located in the housing 101. In this embodiment, the optical plate 102 is a light guide plate of the backlight module 100, and has a light emitting surface 102a, a light incident surface, and a plurality of side surfaces connected to the light emitting surface 102a, for example, the second side surface 102b, the first side surface 102c, and the first side surface 102b. The three sides 102d and the fourth side 102e (as shown in FIG. 1B). The second side surface 102b of the first side surface 102c is a light incident surface of the optical plate 102; the first side surface 102c is located at a side opposite to the second side surface 102b; and the third side surface 102d connects the first side surface 102c and the second side surface 102b. The fourth side 102e is located on the opposite side of the third side 102d.

The light source 105 is disposed adjacent to the light incident surface (second side 102b) of the optical plate 102. In the present embodiment, the light source 105 is located in the housing 101 and is adjacent to the second side 102b. The light emitted by the light source 105 enters the optical plate 102 through the second side surface 102b, and is emitted outward from the light exiting surface 102a of the optical plate 102. In some embodiments of the present invention, the light source 105 may be a Light Emitting Diode (LED), a Cold Cathode Fluorescent Lamp (CCFL), a Hot Cathode Fluorescent Lamp (HCFL), or Other suitable light sources. In the present embodiment, it is preferable to use a light-emitting diode as the light source 105 of the backlight module 100.

In order to avoid light leakage, in some embodiments of the present invention, the backlight module 100 further includes a side plate 108 adjacent to and fixed to the first side surface 102c and having a reflective surface 108a facing the first side surface 102c. The light emitted from the inside of the optical plate 102 and passing outward through the first side surface 102c is reflected into the optical plate 102.

The reflection sheet 103 is disposed in the casing 101 and located between the bottom surface 101a of the casing 101 and the optical plate 102. In some embodiments of the present invention, the reflective sheet 103 may be a metal plate; or a metal layer directly plated on the bottom surface 101a of the housing 101. In the present embodiment, the reflection sheet 103 is a metal plate having a reflection surface 103a facing the surface 102f on the opposite side of the light-emitting surface 102a of the optical plate 102.

The first optical film 104 is disposed above the optical plate 102 and faces the light emitting surface 102a and has at least one extending portion, for example, a first extending portion 104a extending from the vertical wall 101b of the housing 101 and the first side of the optical plate 102. Between 102c. In some embodiments of the present invention, the first optical film 104 is laid flat on the light emitting surface 102a of the optical plate 102, and the first extending portion 104a is extended outward from the edge of the first optical film 104. And by bending to make it with the light-emitting surface 102a An angle θ is sandwiched and received between the vertical wall 101b of the housing 101 and the first side surface 102c to provide a space 106 reserved for thermal expansion of the optical plate 102.

It is to be noted that, in the present embodiment, the angle θ between the first extending portion 104a of the first optical film 104 and the light-emitting surface 102a of the optical plate 102 is preferably 90°. However, in some embodiments of the present invention, in order to allow the space 106 to additionally accommodate other mechanisms, such as a light guide stop (not shown), the first extension 104a of the first optical film 104 and the optical plate 102 The angle θ sandwiched by the light-emitting surface 102a can be adjusted to other angles.

In some embodiments of the present invention, the extension length H of the first extension portion 104a exceeds one-half of the thickness T of the optical plate 102; the maximum height may be substantially equal to the height of the vertical wall 101b of the housing 101 surrounding the bottom surface 101a (ie, The real value is equal to the depth of the housing 101). In some embodiments of the invention, the center of the first extension 104a has at least one opening 104b that facilitates securing the first extension 104a to the first side 102c or the upright wall 101b of the housing 101. For example, when the first extending portion 104a is adhered and fixed to the first side surface 102c of the optical plate 102 by using the single-sided tape 109, the opening of the opening 104b can increase the bonding area of the single-sided tape 109. However, in other embodiments of the invention, the first extension 104a is not provided to any opening (please refer to Figure 6). In addition, for the convenience of folding and fixing, a sachet line (not shown) is preferably disposed between the first extending portion 104a and the edge of the first optical film 104. In an embodiment of the present invention, the first extending portion 104a is attached to the side plate 108 outside the first side surface 102c by a single-sided tape 109 coated with an adhesive layer 109b (please refer to FIG. 1A again). . Wherein, one of the length or the width of the single-sided tape 109 is substantially larger than the extended length H of the first extending portion 104a, or substantially larger than the width of the first extending portion 104a. For example, in the present embodiment, the coverage of the single-sided tape 109 exceeds the size of the first extension portion 104a. Wherein, a part of the adhesive layer 109a of the single-sided tape 109, Facing and directly adhering to the side of the first extending portion 104a away from the side plate 108; the other portion of the adhesive layer 109b is not directly adhered to the first extending portion 104a, but directly adhered to the side plate 108 and not the first The portion where the extension portion 104a contacts (for example, a portion of the adhesive layer 109b is directly adhered to the side plate 108 through the opening 104b), thereby causing the first extension portion 104a to be firmly attached to the side plate 108.

In the present embodiment, the first optical film 104 further includes another second extending portion 104c (as shown in FIG. 1B) extending outward from the other side edge of the first optical film 104 via the bending. Thereafter, it can be accommodated in the space 106 reserved between the vertical wall 101b of the casing 101 and the third side 102d of the optical plate 102.

It is also worth noting that the backlight module 100 may also include other optical films. For example, in the embodiment, in addition to the first optical film 104, the backlight module 100 further includes a second optical film 110 between the first optical film 104 and the light-emitting surface 102a of the optical plate 102. . Like the first optical film 104, the second optical film 110 also has an extending portion 110a (as shown in FIG. 1B), which can be extended by the bending of the vertical wall 101b of the housing 101 and the optical plate 102. A space 106 is reserved between one side 102c. The extension portion 110a of the second optical film 110 preferably does not overlap with the first extension portion 104a of the first optical film 104 to avoid occupying too much the width of the accommodating space 106, so that the original is reserved for the optical The expansion space of the plate 102 is greatly reduced.

In some embodiments of the present invention, the extension portion 110a of the second optical film 110 may also be fixed by the aforementioned single-sided tape 109. In order to simultaneously fix the first extension 104 of the first optical film 104 and the extension 110a of the second optical film 110 to the side panel 108, the length of the single-sided tape 109 preferably spans and covers the first extension. The portion 104 and the extension portion 110a are both in between. And the width of the single-sided tape 109 substantially exceeds the extended length of the first extension portion 104 and the extension portion 110a.

Referring to FIG. 2, FIG. 2 is a cross-sectional view showing a portion of an edge-lit backlight module 200 having a narrow bezel structure according to another preferred embodiment of the present invention. The structure of the backlight module 200 is substantially similar to that of the backlight module 100. The difference is that the backlight module 200 uses different single-sided tapes 209 to fix the first extending portion 104a. For the sake of clarity, the following illustrations will use the same element symbols to identify the same elements.

In the present embodiment, the single-sided tape 209 for fixing the first extending portion 104a to the first side surface 102c of the optical plate 102 has an adhesive surface 209b coated with an adhesive layer 209a. The adhesive surface 209b can be a reflective surface having the same function as the side plate 108 illustrated in FIG. 1A, and the light emitted outward through the first side surface 102c can be reflected into the optical plate 102. Therefore, the side plate 108 can be directly omitted, and the first extending portion 104a is pressed firmly onto the first side surface 102c of the optical plate 102.

In addition, referring to FIG. 3, FIG. 3 is a cross-sectional view showing a partial structure of an edge-lit backlight module 300 having a narrow bezel structure according to another preferred embodiment of the present invention. The structure of the backlight module 300 is substantially similar to that of the backlight module 100. The difference is that the backlight module 300 uses the double-sided tape 309 to fix the first extension portion 104a of the first optical film 104 to the optical plate 102. On one side 102c. In the present embodiment, the double-sided tape 309 has two front and back adhesive faces 309a and 309b which are respectively coated with adhesive layers 309c and 309d; wherein the adhesive layer 309c is adhered to the first optical film 104. The first extension portion 104a faces one side of the first side surface 102c of the optical plate 102, and the size of the double-sided tape 309 is substantially equal to the size of the first extension portion 104a of the extension portion 104a.

Referring to FIG. 6, FIG. 6 is a cross-sectional view showing a portion of an edge-lit backlight module 600 having a narrow bezel structure according to still another preferred embodiment of the present invention. The backlight module 600 has a structure substantially similar to the backlight module. Similar to the 300, the only difference is that the optical film 604 used in the backlight module 600 does not have any openings in the extension portion 604a; and the extension portion 604a is coated with the double-sided adhesive 609a and 609b. The side plate 608 is fixed to the first side surface 102c of the optical plate 102. In this embodiment, the side plate 608 is coated with a side 608a of the adhesive 609a, adhered to the first side 102c of the optical plate 102, and the side plate 608 is coated with the other side 608b of the adhesive 609b, and the optical film is adhered. An extension 604a of the piece 604.

It is worth noting that the above narrow frame structure design can also be applied to a direct type backlight module. For example, referring to FIG. 4, FIG. 4 is a cross-sectional view showing a structure of a direct type backlight module 400 having a narrow bezel structure according to still another preferred embodiment of the present invention. The backlight module 400 includes a housing 101 , an optical plate 102 , a reflective sheet 103 , an optical film 404 , and a light source 405 .

The casing 101 has a bottom surface 101a and a standing wall 101b surrounding the bottom surface 101a of the casing 101. In this embodiment, the housing 101 is preferably a back iron frame of the backlight module 400. The optical plate 102 is located in the housing 101. In this embodiment, the optical plate 102 is a light guide plate or a diffusing plate of the backlight module 400, and has a light emitting surface 102a, a light incident surface, and a plurality of vertical walls connected to the light emitting surface 102a, for example, the second side surface 102b and the first side surface. 102c. The second side 102b is located on the opposite side of the first side 102c. The light incident surface of the optical plate 102 is a surface 102f on the opposite side of the first side surface 102a. The light source 405 is located between the optical plate 102 and the reflective sheet 103. The light emitted by the light source 405 passes through the optical plate 102 and is emitted outward from the light exit surface 102a.

The optical film 404 is disposed above the optical plate 102 and faces the light exit surface 102a and has at least one extension, such as extensions 404a and 404b. The extension portion 404a is extended between the vertical wall 101b of the housing 101 and the second side surface 102b of the optical plate 102 by bending; the extension portion 404b is extended to the vertical wall of the housing 101. Between 101b and the first side 102c of the optical plate 102, it is further received in a space 106 reserved between the housing 101 and the optical plate 102. In the embodiment, the backlight module 400 uses the double-sided tape 309 as shown in FIG. 3 to fix the extensions 404a and 404b to the second side 102b and the first side 102c of the optical plate 102, respectively. Since the structure of the double-sided tape 309 and its fixing manner have been described in detail in FIG. 3, it will not be described here.

The backlight module of all the above embodiments can be further applied to the display element whether it is a sidelight type or a direct backlight module. For example, please refer to FIG. 5. FIG. 5 is a cross-sectional view showing the structure of a display 40 using a direct type backlight module 400 having a narrow bezel structure according to an embodiment of the invention. The display 40 includes the direct type backlight module 400 and the display panel 41 illustrated in FIG. 4 . The backlight module 400 includes a housing 101 , an optical plate 102 , a reflective sheet 103 , and an optical film 404 .

The optical plate 102 is located in the housing 101 and has a light exiting surface 102a, a light incident surface and a plurality of side surfaces, such as a second side surface 102b and a first side surface 102c. Wherein, the second side surface 102b and the first side surface 102c are connected to the light-emitting surface 102a; and the second side surface 102b is opposite to the first side surface 102c. The light incident surface of the optical plate 102 is a surface 102f on the opposite side of the light emitting surface 102a. The reflection sheet 103 is located between the casing 101 and the optical plate 102 and faces the opposite side of the light-emitting surface 102a. The light source 405 is located between the optical plate 102 and the reflective sheet 103. The optical film 404 faces the light exit surface 102a and has extensions 404a and 404b extending between the housing 101 and the second side 102b and the first side surface 102c, respectively. The display panel 41 is disposed on one side of the backlight module 400.

According to the above, an embodiment of the present invention provides a backlight module and an application device thereof, wherein the backlight module includes an optical film facing the light emitting surface of the backlight module. The edge has an extension portion extending from the back panel of the backlight module and used for bearing Between the sides of the optical plate carrying the optical film; and by attaching the tape to the extension, the optical film can be attached to the side of the optical plate.

Since the back plate and the side of the optical plate for carrying the optical film are originally reserved for the thermal expansion space of the optical plate, the spatial size is much larger than the thickness of one optical film. Therefore, the extension portion is accommodated in this reserved space, and in addition to the thickness of the optical film, it does not occupy too much space, and there is no need to additionally increase the frame size. In addition, the use of relatively small-sized tape instead of the conventional optical film positioning structure such as positioning pin, back plate folding wall or mounting ear to fix the optical film not only has the technical advantage of reducing the width of the frame, but also conforms to the current Design requirements for small border backlight modules. Moreover, since the expansion coefficient of the optical plate is generally larger than the expansion coefficient of the optical film, and the optical film is fixed on the side of the optical plate by at least one extension portion; therefore, when operated, the optical film expands The optical plate with a larger coefficient expands and is stretched synchronously to be flatter. There is no problem that the expansion space is insufficiently reserved, and the back plate is pressed and warped, or is broken by the hanging ear, which is more helpful to improve the light uniformity of the backlight module.

While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

40‧‧‧ display

41‧‧‧ display panel

100‧‧‧Side-light backlight module

101‧‧‧shell

101a‧‧‧ bottom

101b‧‧‧立立

102‧‧‧Optical board

102a‧‧‧Glossy

102b‧‧‧ second side

102c‧‧‧ first side

102d‧‧‧ third side

102e‧‧‧fourth side

102f‧‧‧ surface

103‧‧‧reflector

103a‧‧‧reflecting surface

104‧‧‧First optical diaphragm

104a‧‧‧First Extension

104b‧‧‧Opening

104c‧‧‧Second extension

105‧‧‧Light source

106‧‧‧ Space

108‧‧‧ side panels

108a‧‧‧reflecting surface

109‧‧‧Single-sided tape

109a‧‧‧Partial adhesive layer

109b‧‧‧Other part of the adhesive layer

110‧‧‧Second optical film

110a‧‧‧Extension

200‧‧‧Side-light backlight module

209‧‧‧Single-sided tape

209a‧‧ ‧ adhesive layer

209b‧‧‧adhesive surface

300‧‧‧Side-light backlight module

309‧‧‧Double-sided tape

309a‧‧‧adhesive surface

309b‧‧‧adhesive surface

309c‧‧ ‧ adhesive layer

309d‧‧‧adhesive layer

400‧‧‧Direct type backlight module

404‧‧‧Optical diaphragm

404a‧‧‧Extension

404b‧‧‧Extension

405‧‧‧Light source

600‧‧‧Backlight module

604‧‧‧Optical diaphragm

604a‧‧‧Extension

608‧‧‧ side panel

608a‧‧‧ side of the side panel

608b‧‧‧The other side of the side panel

609a‧‧‧ Backing

609b‧‧‧ Backing

Θ‧‧‧ angle

H‧‧‧Extension length of the extension

T‧‧‧ side thickness

S‧‧‧ tangent

1A is a cross-sectional view showing the structure of an edge-lit backlight module having a narrow bezel structure according to an embodiment of the invention.

FIG. 1B is a partial perspective structural view of the backlight module according to FIG. 1A.

2 is a diagram of a preferred embodiment according to the present invention A schematic cross-sectional view of a partial structure of an edge-lit backlight module with a narrow bezel structure.

3 is a cross-sectional view showing a portion of an edge-lit backlight module having a narrow bezel structure according to another preferred embodiment of the present invention.

4 is a cross-sectional view showing a structure of a direct type backlight module having a narrow bezel structure according to still another preferred embodiment of the present invention.

FIG. 5 is a cross-sectional view showing the structure of a display using a direct type backlight module having a narrow bezel structure according to a preferred embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a portion of a side-lit backlight module having a narrow bezel structure according to still another preferred embodiment of the present invention.

100‧‧‧Side-light backlight module

101‧‧‧shell

101a‧‧‧ bottom

101b‧‧‧立立

102‧‧‧Optical board

102a‧‧‧Glossy

102b‧‧‧ second side

102c‧‧‧ first side

102f‧‧‧ surface

103‧‧‧reflector

103a‧‧‧reflecting surface

104‧‧‧Optical diaphragm

104a‧‧‧Extension

105‧‧‧Light source

106‧‧‧ Space

108‧‧‧ side panels

108a‧‧‧reflecting surface

109‧‧‧Single-sided tape

109a‧‧‧Partial adhesive layer

109b‧‧‧Other part of the adhesive layer

110‧‧‧Optical diaphragm

H‧‧‧Extension length of the extension

T‧‧‧ side thickness

Claims (20)

A backlight module includes: a housing; an optical plate located in the housing, and having a light emitting surface, a light incident surface, and a first side connected to the light emitting surface; a light source adjacent to the light source a light-incident surface; a reflective sheet located between the housing and the optical plate and facing the opposite side of the light-emitting surface; a first optical film facing the light-emitting surface and having a first extension portion extending Between the housing and the first side; and a second optical film between the first optical film and the light-emitting surface, having a second extension extending from the housing and the first Between the sides, and not overlapping the first extension. The backlight module of claim 1, wherein the first extension is fixed to the first side by a double-sided tape or a single-sided tape. The backlight module of claim 2, further comprising a side plate disposed on the first side, having a reflecting surface facing the first side. The backlight module of claim 3, wherein the single-sided tape has a coverage beyond the first extension, and one of the adhesive faces of the single-sided tape faces the side panel. The backlight module of claim 2, wherein the single side The adhesive tape has a coverage beyond the first extension, and one of the adhesive faces of the single-sided adhesive tape is a reflective surface. The backlight module of claim 1, wherein the first extension has an extended length that exceeds one-half of a thickness of the optical plate. The backlight module of claim 1, wherein the light incident surface of the optical plate is located on an opposite side of the first side. The backlight module of claim 1, wherein the light incident surface of the optical plate is located on an opposite side of the light emitting surface, and the light source is located between the optical plate and the reflective sheet. The backlight module of claim 1, wherein the first optical film further has a third extending portion extending between the housing and a third side of the optical plate. The backlight module of claim 1, wherein the first extension has an opening. A display device includes: a backlight module, comprising: a housing; an optical plate located in the housing, and having a light emitting surface, a first side connected to the light emitting surface, and the first surface a second side of the side; a light source disposed between the housing and the optical plate; a reflective sheet located between the housing and the optical plate and facing the opposite side of the light emitting surface; a first optical film facing The light exiting surface has a first extending portion extending between the housing and the first side surface; and a second optical film between the first optical film and the light emitting surface, having a second The extension portion extends between the housing and the first side surface and does not overlap with the first extension portion; and a display panel is disposed on one side of the backlight module. The display element of claim 11, wherein the extension is fixed to the first side by a double-sided tape or a single-sided tape. The display element of claim 11, further comprising a side plate adjacent to the first side and having a reflecting surface facing the first side. The display element of claim 13, wherein the one-sided tape has a range beyond the first extension, and one of the adhesive faces of the one-sided tape faces the side panel. The display element of claim 12, wherein the single-sided tape has a range beyond the first extension, and one of the adhesive faces of the single-sided tape is a reflective surface. The display element of claim 11, wherein the first extension has an extended length that exceeds a thickness of one of the thickness of the optical plate. One. The display element of claim 11, wherein the light source is adjacent to the second side. The display element of claim 11, wherein the light source is located between the optical plate and the reflective sheet. The display element of claim 11, wherein the first optical film further has a third extension extending between the housing and a third side of the optical plate. The display element of claim 11, wherein the first extension has an opening.