KR102490168B1 - Display Device - Google Patents

Abstract

The present invention relates to a display device, wherein an edge of an optical sheet constituting a backlight unit is attached to and fixed to a bottom surface of a guide panel, the height of the attachment surface of the optical sheet and the guide panel is lower than the reference surface of the optical sheet, By fixing the sheet with downward tension applied, the optical sheet and its lower parts can be firmly supported, deformation of the optical sheet due to heat or humidity can be prevented, and moisture permeation from the outside can be prevented. .

Description

Display Device {Display Device}

The present invention relates to a display device, and more particularly, to a display device having a structure capable of firmly fixing an optical sheet included in a backlight unit for a display device.

As the information society develops, the demand for display devices for displaying images is increasing in various forms. Recently, liquid crystal displays (LCDs), plasma displays (PDPs), organic electric fields Various display devices such as an organic light emitting diode display device (OLED) are being used.

Among such display devices, a liquid crystal display (LCD) includes an array substrate including a thin film transistor as a switching element for controlling each pixel area on/off, and a color filter and/or a black matrix. It consists of an upper substrate, a display panel including a liquid crystal material layer formed therebetween, a driving unit for controlling thin film transistors, and a back light unit (BLU) providing light to the display panel. , It is a device that displays an image by adjusting the arrangement state of the liquid crystal layer according to the electric field applied between the pixel (PXL) electrode and the common voltage (Vcom) electrode provided in the pixel area and adjusting the transmittance of light accordingly.

In the case of such a liquid crystal display device, there must be a backlight device that provides light from the outside, and this backlight unit may include a light source and subunits such as a light guide plate, a reflector, and an upper sheet, and support for mounting these subunits. It includes one or more frames or chassis as a structure.

As such a frame or chassis, a cover bottom, which is a plate-like member supporting parts of the side and rear surfaces of the backlight unit, and a guide panel provided in relation to the cover bottom to support between the backlight unit and the display panel Alternatively, a guide sheet or the like is used.

Meanwhile, a plurality of optical sheets for diffusing or concentrating light from the light guide plate are used in the backlight unit. These optical sheets are disposed on the light guide plate, but may not be adhered to the light guide plate and thus have fluidity, so that a frame, etc. It needs to be supported and fixed to some of the display device support structures.

In this way, although various methods have been developed to fix the optical sheet constituting the backlight unit, there are problems in that the structure is complicated or the supporting force is not provided in a certain direction.

In addition, according to the recent thinning trend of display devices and the trend of narrow bezels to reduce the width of the bezel portion of display devices, various limitations exist in the existing structure for fixing the optical sheet to the display device. this is happening

The present invention focuses on this point, and proposes a structure capable of firmly supporting the optical sheet of the backlight unit even when the thickness and bezel width of the display device are small.

Against this background, an object of the present invention is to provide a display device including a support structure for firmly fixing an optical sheet of a backlight unit.

Another object of the present invention is to attach and fix the edge of the optical sheet constituting the backlight unit to the bottom surface of the guide panel, arrange the height of the attachment surface of the optical sheet and the guide panel to be lower than the reference surface of the optical sheet, By fixing the optical sheet in a tensioned state, an optical sheet is firmly fixed, deformation due to heat or humidity is prevented, and moisture permeation from the outside can be prevented.

Another object of the present invention is to form a guide panel supporting a display panel in an upper and lower split type, fix an edge of an optical sheet to a coupling portion of the upper and lower guide panels, and form the coupling portion of the upper and lower guide panels to be lower than the reference plane of the optical sheet. Accordingly, an object of the present invention is to provide a display device capable of firmly fixing an optical sheet.

Another object of the present invention is to attach and fix the edge of the uppermost optical sheet among the plurality of optical sheets disposed on the light guide plate of the backlight unit to the lower surface of the guide panel, and the uppermost optical sheet is made of a lower expansion material or a lower moisture absorption material than the rest of the optical sheets. Accordingly, it is to provide a display device capable of preventing display defects due to expansion of the optical sheet due to heat or moisture while firmly fixing the optical sheet.

In order to achieve the above object, in one embodiment of the present invention, in a display device including a display panel, a guide panel, and a backlight unit, an edge portion of an optical sheet included in a backlight unit is attached to and fixed to the bottom surface of the guide panel, The edge portion of the optical sheet and the attachment surface of the guide panel may be disposed lower than the reference surface of the central region of the optical sheet.

In this case, the guide panel may be configured as a separate type of an upper guide panel and a lower guide panel, and the optical sheet may be attached to and fixed to a coupling surface of the upper guide panel and the lower guide panel.

In addition, in order to combine the detachable guide panel and the optical sheet, the upper guide panel includes a protrusion and/or a hook, the lower guide panel includes a corresponding accommodation groove and/or a hook groove, and the edge of the optical sheet includes a protrusion. It may include a mounting slot into which is inserted.

The optical sheet includes one or more lower optical sheets and an uppermost optical sheet disposed on the lower optical sheet. In this case, only an edge portion of the uppermost optical sheet may be attached to and fixed to the lower surface of the guide panel, and the uppermost optical sheet may be It may be made of a material having a lower thermal expansion coefficient than the material of the lower optical sheet or having a low moisture absorption characteristic.

According to one embodiment of the present invention, there is an effect of firmly fixing the optical sheet of the backlight unit to the support structure of the display device.

In addition, the edge of the optical sheet constituting the backlight unit is attached to and fixed to the bottom surface of the guide panel, but the height of the attachment surface of the optical sheet and the guide panel is lower than the reference surface of the optical sheet, and tension is applied to the optical sheet. By being fixed, the optical sheet and its lower parts can be firmly supported, deformation of the optical sheet due to heat or humidity can be prevented, and moisture permeation from the outside can be prevented.

In addition, by forming a guide panel supporting the display panel in a vertical split type, fixing the edge of the optical sheet to a coupling part of the upper and lower guide panels, and forming the attachment surface of the upper and lower guide panels to be lower than the reference surface of the optical sheet, The optical sheet may be firmly fixed to the support structure of the display device in a state in which tension is applied.

In addition, by attaching and fixing the edge of the uppermost optical sheet among the plurality of optical sheets disposed on the light guide plate of the backlight unit to the lower surface of the guide panel, the uppermost optical sheet is made of a lower expansion material or a lower moisture absorption material than the rest of the optical sheets, While firmly fixing the optical sheet, display defects due to expansion of the optical sheet due to heat or moisture may be prevented.

1 shows a cross-section of a general type liquid crystal display to which the present invention can be applied.
2 shows an embodiment of a structure for fixing an optical sheet.
3A is a cross-sectional side view of a display device using the optical sheet fixing method of FIG. 2, and FIG. 3B is a partial plan view.
FIG. 4 is a cross-sectional view of a display device using an optical sheet fixing method according to an exemplary embodiment. FIG. 4A shows a state before the optical sheet is fixed, and FIG. 4B shows a state after the optical sheet is fixed.
5A is a plan view of an uppermost optical sheet having mounting slots according to an exemplary embodiment, and FIG. 5B illustrates an upper guide panel having protrusions inserted into the mounting slots of the uppermost optical sheet.
6 is a plan view of an uppermost optical sheet according to another embodiment, showing a structure in which mounting slots are intermittently formed along one side of the uppermost optical sheet.
7 shows a hook-type coupling structure that is an example of a coupling structure between an upper guide panel and a lower guide panel.
8 is a diagram illustrating various effects when an optical sheet fixing method according to the present embodiment is applied.
FIG. 9 shows an optical sheet fixing method according to another embodiment of the present invention. FIG. 9A shows a state before the optical sheet is fixed, and FIG. 9B shows a state after the optical sheet is fixed.
FIG. 10 shows an optical sheet fixing method according to another embodiment of the present invention. FIG. 10A shows a state before the optical sheet is fixed, and FIG. 10B shows a state after the optical sheet is fixed.
11 is a detailed configuration diagram of an optical sheet used in this embodiment, showing an example of one or more lower optical sheets and an uppermost optical sheet disposed thereon.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention are described in detail below with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even if they are displayed on different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

Also, terms such as first, second, A, B, (a), and (b) may be used in describing the components of the present invention. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the corresponding component is not limited by the term. When an element is described as being “connected,” “coupled to,” or “connected” to another element, that element is or may be directly connected to that other element, but intervenes between each element. It will be understood that may be "interposed", or each component may be "connected", "coupled" or "connected" through other components.

Figure 1 shows a side cross-sectional view of a liquid crystal display device of a general structure to which the present invention can be applied.

As shown in FIG. 1 , a display device to which the present invention can be applied includes a display panel 140 such as a liquid crystal display panel and a backlight unit 120 disposed under the display panel and radiating light to the display panel, and the backlight unit 120 ) and a metal or plastic cover bottom or plate bottom 110 extending over the entire rear surface of the display device.

In addition, a plastic guide panel 140 having a structure that is fixed to the plate bottom 110 and connects the backlight unit 120 and the display panel 140 may be additionally provided. A double-sided tape (not shown) is attached to a portion of the upper surface of the horizontally extended portion of the guide panel 130 and the display panel 140 is disposed thereon, so that the display panel can be fixedly mounted.

In addition, the display device may further include a case top 150 that covers the side surface of the outermost plate bottom 110 and is bent and extended to a part of the front surface of the display panel to protect the front edge of the display panel. .

The case top 150 surrounds the side surface of the plate bottom 110 and extends to a partial area of the front portion of the display panel 140 to protect the display panel and simultaneously drive a display device that can be disposed behind the plate bottom. It performs a function of protecting a chip-on-film (COF) circuit part, which is a connection circuit for connecting a printed circuit board (not shown) and a display panel.

In the case of a liquid crystal display panel, the display panel 140 includes a plurality of gate lines and data lines and pixels defined at intersections thereof, and a thin film transistor as a switching element for controlling light transmittance in each pixel. It may include an array substrate, an upper substrate having a color filter and/or a black matrix, and a liquid crystal material layer formed therebetween.

Meanwhile, the display panel to which the present invention can be applied is not limited to such a liquid crystal display panel, and all types of display panels displaying images by receiving light from a backlight unit as well as display devices such as plasma displays. can include

On the other hand, the backlight unit 120 used in the liquid crystal display to which an embodiment of the present invention can be applied includes a light source module (not shown) including a light source such as an LED, a holder for fixing the light source, and a light source driving circuit, A light guide plate (122) or diffuser plate for diffusing light to the entire panel area, a reflector 124 for reflecting light toward the display panel, and a circuit for controlling the on/off of the light source. It may include sub-units such as a circuit and one or more optical sheets 126 disposed on the light guide plate to improve luminance, diffuse and protect light, and the like.

Among the backlight unit 120, the optical sheet 126 is disposed on the light guide plate 122 and may not be bonded to the light guide plate 122.

Even if the optical sheet 126 is adhered to the upper surface of the light guide plate 122, external impact may be applied during transportation or testing to mount the display device on a set device, which is a final electronic product such as a laptop computer or TV. In this case, the optical The position of the seat 126 may vary.

As will be described later, since the optical sheet 126 functions to condense and diffuse light from the light guide plate, a display image may be deteriorated when the position of the optical sheet 126 is changed.

Therefore, it is necessary to prevent positional change of the optical sheet by fixing the optical sheet to the rest of the fixing support structure of the display device, in addition to simply seating the optical sheet on the upper portion of the light guide plate.

To this end, various types of optical sheet structures have been proposed, and FIG. 2 shows one example of them.

FIG. 2 shows an embodiment of a structure for fixing an optical sheet, FIG. 3A is a side cross-sectional view of a display device using the optical sheet fixing method of FIG. 2 , and FIG. 3B is a partial plan view.

According to the optical sheet fixing structure shown in FIGS. 2 and 3 , a portion of the edge of the optical sheet 226 has a rectangular protrusion 227 protruding outwardly, and the guide panel 230 has a rectangular protrusion 227 of the optical sheet. A seating groove 232 for accommodating is formed.

According to this structure, the rectangular protrusion 227 of the optical sheet 226 is seated in the seating groove 232 of the guide panel 232, and then a foam pad 272, which is a kind of single-sided adhesive tape, is attached to the upper portion of the optical sheet 226 to provide optical protection. The sheet is fixed to the guide panel.

At this time, as shown in FIG. 2B, the fixing of the optical sheet is performed at two or three positions of one side of the panel.

However, in the optical sheet fixing method of FIGS. 2 and 3, the upper surface of the rectangular protrusion 227 of the optical sheet is bonded to the adhesive surface of the lower surface of the foam pad 270, and has the following disadvantages.

The first disadvantage occurs during transportation or testing of the display device, and although the rectangular protrusion 227 of the optical sheet is adhesively fixed to the lower surface of the foam pad 270, strong external impact is applied during movement or testing of the display device. When received, the adhesion with the foam pad may fall, and the contact with the foam pad is released, and the optical sheet may flow in the X direction in FIG. 2 .

The second disadvantage occurs during the use of the display device. When the display device is in use, heat from the light source of the backlight unit is transferred to the light guide plate and the optical sheet, and thus the light guide plate and the optical sheet are repeatedly expanded and contracted by the heat. . However, in the structure shown in FIGS. 2 and 3, since the optical sheet is adhesively fixed to the foam pad and the guide panel, when thermal deformation in the X direction occurs during use of the display device, such thermal deformation cannot be accommodated, resulting in As a result, problems such as bending of the optical sheet may occur.

The third disadvantage is a problem caused by the thin and narrow bezel trend of the display device.

Recently, the size of the edge area of the display device is decreasing according to the thinning trend of thinning the thickness T of the display device and the narrow bezel trend to reduce the width of the bezel portion of the display device.

Therefore, in the conventional structure for fixing the optical sheet to the display device as shown in FIGS. 2 and 3, when the bezel width Wb, which is the panel edge area, is reduced, it is difficult to design the protruding part of the optical sheet and the size of the protruding part and the fixing area accordingly As a result, the fixing force of the optical sheet is reduced.

Therefore, there is a possibility that the optical sheet and its lower parts may flow due to external impact, and in this process, there is a high possibility that defects such as wrinkles and splits of the optical sheet may occur due to friction between parts.

In addition, since the fixing force of the optical sheet is weakened due to the decrease in the fixing area, the possibility of deformation of the optical sheet due to heat and humidity increases.

In addition, as shown in FIG. 3B, a certain gap g is formed between the protruding part 227 of the optical sheet and the seating groove 232 of the guide panel 230 by design. There is a possibility of penetrating into the inside of the display device, and there is also a concern that a light leakage phenomenon in which light leaks through such a gap may occur.

The present specification is proposed to solve the disadvantages of the optical sheet fixing method according to FIGS. 2 and 3, and the edge portion of the uppermost optical sheet among the optical sheets is directly attached to a guide panel and mounted on the bottom of the cover to be fixed. The attachment surface of the sheet and the guide panel is configured to be lower than the reference surface of the uppermost optical sheet.

Hereinafter, a display device including an optical sheet fixing structure according to various embodiments of the present invention will be described with reference to FIGS. 4 to 11 .

FIG. 4 is a cross-sectional view of a display device using an optical sheet fixing method according to an exemplary embodiment. FIG. 4A shows a state before the optical sheet is fixed, and FIG. 4B shows a state after the optical sheet is fixed.

The display device according to the present embodiment includes a display panel 440, a guide panel 430 supporting the lower edge of the display panel, and a backlight unit including optical sheets 426 and 426', the guide panel and the backlight unit. and a cover bottom 410 supporting the uppermost optical sheet 426' among the optical sheets, and the edge portion of the uppermost optical sheet 426' is attached to and fixed to the lower surface of the guide panel, and the edge portion of the uppermost optical sheet and the attachment surface S2 of the guide panel are fixed. The height H2 is lower than the height H1 of the reference plane S1, which is the remaining surface of the uppermost optical sheet.

Therefore, as shown in FIG. 4B, the uppermost optical sheet 426' can be fixed while having tension Ft, which is a force directed toward the lower portion of the display device, thereby enabling the optical sheet and its lower parts to be firmly fixed or supported. .

In addition, since the edge of the optical sheet is fixed to the guide panel as a whole, the fixing power of the optical sheet is improved compared to the method in which only a partial area is fixed as shown in FIGS. 2 and 3, and furthermore, the optical sheet can be firmly fixed even in a narrow bezel environment. It happens.

Meanwhile, the backlight unit includes a light source (not shown), a light guide plate 422 transmitting light from the light source, and a reflector 424 disposed under the light guide plate, and two optical sheets are provided on the light guide plate 422. can be placed above.

In this case, the two or more optical sheets may include one or more lower optical sheets disposed on the light guide plate and an uppermost optical sheet disposed over the lower optical sheets.

In this embodiment, all of the two or more optical sheets may be fixed to the guide panel in the above structure, but only the edge of the uppermost optical sheet may be attached to and fixed to the lower surface of the guide panel in the above structure.

4 shows a first embodiment of the present invention, in which the guide panel 430 is divided into an upper guide panel 432 and a lower guide panel 434, and the uppermost optical sheet is the upper guide panel and the lower guide. It is attached and fixed to the bonding surface of the panel.

In addition, in the embodiment of FIG. 4, the upper guide panel 432 is provided with a protrusion 433 disposed in the longitudinal direction, and the lower guide panel 434 is provided with a receiving groove 435 in which the protrusion is received and coupled. At the edge of the uppermost optical sheet 426', a mounting slot 427 into which the protruding portion 433 of the upper guide panel is inserted is formed.

In addition, the height h of the upper surface of the lower guide panel is lower than the height h' of the upper surface of the lower optical sheet 426 .

As shown in FIG. 4A , parts of the backlight unit composed of the reflector 424, the light guide plate 422, and the lower optical sheet 426 are disposed on the inner surface of the cover bottom 410, and the mounting slot 427 of the uppermost optical sheet 426'. After mounting the protrusion 433 of the upper guide panel 432 to be inserted into the upper guide panel 432, the protrusion 433 of the upper guide panel 432 is pressed into the receiving groove 435 of the lower guide panel 434 and coupled.

Therefore, the edge of the uppermost optical sheet 426' is fixed at the bonding surface between the upper guide panel 432 and the lower guide panel 434, and the height H2 of S2, which is the attachment surface between the edge of the uppermost optical sheet and the guide panel, is It is fixed so as to be lower than the height H1 of the reference plane S1, which is the central area surface of the uppermost optical sheet 426'.

As a result, as shown in FIG. 4B, the edge of the uppermost optical sheet 426' is fixed in a state in which tension Ft, which is a downward force, is applied.

In addition, according to the embodiment of FIG. 4 , the edge portion of the uppermost optical sheet 426' is firmly fixed to the guide panel as a whole.

Therefore, even if the width of the bezel is reduced, the optical sheet constituting the backlight unit can be securely fixed, and since the top optical sheet is fixed with the lower tension applied, movement of the lower parts including the light guide plate and the lower optical sheet can be prevented. can

5A is a plan view of an uppermost optical sheet having mounting slots according to an exemplary embodiment, and FIG. 5B illustrates an upper guide panel having protrusions inserted into the mounting slots of the uppermost optical sheet.

6 is a plan view of an uppermost optical sheet according to another embodiment, showing a structure in which mounting slots are intermittently formed along one side of the uppermost optical sheet, and FIG. 7 is an example of a coupling structure between an upper guide panel and a lower guide panel. The hook-type coupling structure is shown.

As shown in FIG. 5A , mounting slots 427 may be formed on all four sides constituting the edge of the uppermost optical sheet 426', except for the side where the light source unit of the backlight unit is disposed.

As shown in FIG. 5B, the protruding portion 433 of the upper guide panel 432 is also disposed to protrude in the longitudinal direction on three sides of the upper guide panel to correspond to the formation position of the mounting slot as shown in FIG. 5A.

Of course, as shown in FIG. 6, the mounting slots 427 and 427' are not entirely formed on one side of the uppermost optical sheet 426', but two or more are intermittently formed on one side of the uppermost optical sheet 426'. may be formed. In this case, two or more protrusions of the upper guide panel should also be formed on one side.

In addition, as shown in FIG. 7, the protruding part 433 of the upper guide panel includes a hook part 433', and the receiving groove 435 of the lower guide panel 434 has a hook groove 435 into which the hook part is inserted. ') can be formed.

In this way, since the upper guide panel and the lower guide panel are coupled in a hook structure, the coupling force of the guide panel can be increased and assembly convenience can be provided.

As shown in FIG. 4, the process of fixing the edge of the uppermost optical sheet to the guide panel is facilitated by configuring the guide panel as a top-down separable type that is press-fitted or hook-coupled, and forming a mounting slot at the edge of the uppermost optical sheet. This has the effect of simplifying the assembly process.

In addition, as will be described in detail with reference to FIG. 11 , the optical sheet includes one or more lower optical sheets and an uppermost optical sheet disposed on the lower optical sheet, and at this time, only the edge of the uppermost optical sheet is attached to the lower surface of the guide panel. and fixed, there is an advantage in that it is sufficient to change only the structure of the uppermost optical sheet without changing the structure of the lower optical sheet among the plurality of optical sheets.

In addition, since the lower optical sheet is partially protected from the influence of heat or external moisture by the uppermost optical sheet, there is an advantage in that the selection of materials for the lower optical sheet can be widened.

Hereinafter, detailed configurations of components constituting a display device according to an embodiment of the present invention will be described in detail.

In an embodiment of the present invention, the light source unit of the backlight unit may include a light source element and a light source holder having a long plate-like structure including a light source element and an LED driving circuit for supporting the light source element and driving the light source, and the light source element of the light source module is a light emitting diode. (LED) or a light emitting diode strip may be used, but is not limited thereto, and any type of light source may be used as long as it can provide necessary light to the display panel.

The light guide plate (LGP) 422 may be formed of a rectangular clear plastic sheet that is generally die-cut, extruded, or injection molded from a plastic sheet, and light from a light source such as a light emitting diode array is directed toward the edges of the light guide plate. is emitted into the light guide plate, is totally reflected inside the light guide plate, diffuses across the rear surface of the display panel, and the light emitted through the flat top surface of the light guide plate functions as a backlight of the display panel.

Materials constituting the light guide plate 422 include polymethyl methacrylate (PMMA), MS (methlystylene) resin, polystyrene (PS), polypropylene (PP), and polyethylene terephthalate. :PET) and polycarbonate (PC), but may be at least one light-transmissive material selected from, but is not limited thereto.

The reflector 424 is positioned on the rear surface of the light guide plate 422 and functions to improve the luminance of light by reflecting light passing through the rear surface of the light guide plate toward the display panel 440 .

The optical sheets 426 and 426' disposed on the light guide plate 422 include a light collecting sheet or prism sheet (PS) that functions to collect light, a diffusing sheet (DS) that diffuses light, and a DBEF ( It can be composed of two or more sheets among various functional sheets, such as a reflective polarizing film for brightness enhancement called a dual brightness enhancement film), and a more uniform surface light source for the display panel by diffusing or concentrating the light passing through the light guide plate. to be admitted.

At this time, the edge of the uppermost optical sheet 426' among the optical sheets used in the embodiment of the present invention is attached to the lower surface of the guide panel, and in particular, in the embodiment of FIG. 4, the edge of the uppermost optical sheet 426'. A mounting slot 427 may be formed.

In general, among the functional individual sheets constituting the optical sheets 426 and 426', the light collecting sheet PS has a light collecting function of collecting incident light in a certain direction by including a certain light collecting pattern in a sheet in the form of a transparent film. do.

On the other hand, a diffuser sheet (DS) that diffuses light is an optical sheet that functions to diffuse incident light in various directions, and may be configured to include a certain diffusion pattern or diffusion particles in a sheet in the form of a transparent film. there is.

In addition, the reflective polarizing film is an optical film that transmits only light vibrating in one direction among incident natural light while vibrating in various directions and reflects light vibrating in the other direction, and improves brightness called DBEF (dual brightness enhancement film; DBEF). It is a concept that includes film.

The cover bottom 410 constitutes the rear and side exteriors and support of the display device according to the present embodiment, and is a frame structure made of metal or plastic material that is bent in an L-shape as a whole.

The lower surface of the lower guide panel 434 is seated on the inner surface of the cover bottom 410, and a double-sided tape or the like is disposed therebetween to couple the guide panel and the cover bottom.

The guide panel 430 according to the present embodiment has a frame structure made of plastic or metal, and is coupled to the inner surface of the sidewall of the cover bottom 410, and the edge of the display panel 440 is seated and supported on the upper surface of the guide panel. do.

The guide panel 430 may be a separable structure including two upper guide panels 432 and a lower guide panel 434 coupled to a protrusion and a receiving groove or a hook structure, as in the embodiment of FIG. 4, but is limited thereto. It is not.

For example, as shown in FIG. 9, the guide panel may be a separable structure in which the lower surface of the upper guide panel 532 and the upper surface of the lower guide panel 534 are coupled by an adhesive pad or the like without protrusions or receiving grooves, As shown in FIG. 10, it may be a single non-separable guide panel 630.

Meanwhile, in the present specification, the cover bottom 410 is not limited to the term, and includes a plate bottom, a base frame, a metal frame, a metal chassis, and a chassis base ( Chassis Base), m-chassis, etc., and can be used as a support for fixing at least one of the display panel and the backlight unit, and should be understood as a concept including all types of frames or plate-shaped structures disposed at the very base of the display device. something to do.

In addition, the guide panel 430 in the present specification may be replaced with other expressions such as a plastic chassis, a p-chassis, a support main, a main support, a mold frame, and the like, and a square frame-shaped structure having a cross-sectional shape with a plurality of bent parts. It should be understood that the term includes all types of plastic members connected to the cover bottom 410 and used to support the optical sheet and the display panel of the backlight unit.

The guide panel 600 is made of a mold material of a synthetic resin such as polycarbonate, and may be manufactured through an injection molding method, but is not limited thereto.

Also, although not shown, a case top extending from the side of the cover bottom to a part of the front surface of the display panel to protect a part of the front surface of the display panel may be further included.

When the display panel 440 used in the display device according to the present embodiment is a liquid crystal display panel, a plurality of gate lines and data lines and pixels defined in the intersection area thereof, and the light transmittance of each pixel are adjusted. It may include an array substrate including a thin film transistor as a switching element, an upper substrate including a color filter and/or a black matrix, and a liquid crystal material layer formed therebetween.

In this specification, the term "display device" refers to a display device in a narrow sense such as a liquid crystal module (LCM) including a display panel and a driving unit for driving the display panel, as well as a laptop computer that is a finished product including such an LCM. , It is used as a concept including set electronic devices or even set devices, such as televisions, computer monitors, mobile electronic devices such as smart phones or electronic pads.

That is, the display device in this specification is used in the sense of including not only a narrow display device such as an LCM, but also a set device, which is an application product including the display device.

8 is a diagram illustrating various effects when an optical sheet fixing method according to the present embodiment is applied.

As shown in FIG. 8, according to the present embodiment, the edge of the uppermost optical sheet 426' among the optical sheets constituting the backlight unit is attached to the lower surface of the guide panel and fixed, but the edge of the uppermost optical sheet and the guide panel are attached. By making the height of the surface lower than the height of the reference plane of the central region of the uppermost optical sheet, the optical sheet is fixedly coupled with the lower tension applied to the uppermost optical sheet.

Accordingly, it is possible to firmly fix or support the optical sheet and lower parts thereof, and to prevent movement of parts such as the light guide plate and the lower optical sheet disposed under the uppermost optical sheet.

In addition, since the edge of the optical sheet is fixed to the guide panel as a whole, the fixing power of the optical sheet is improved compared to the method in which only a partial area is fixed as shown in FIGS. 2 and 3, and furthermore, the optical sheet can be firmly fixed even in a narrow bezel environment. It happens.

In addition, since the edge of the uppermost optical sheet is assembled to the guide panel as a whole without any gaps, penetration of moisture or foreign matter through the gap between the protruding part (edge part) of the optical sheet and the guide panel, which occurred in the structures shown in FIGS. 2 and 3 There is also an effect of preventing a defect due to or a light leakage phenomenon through a gap.

FIG. 9 shows an optical sheet fixing method according to another embodiment of the present invention. FIG. 9A shows a state before the optical sheet is fixed, and FIG. 9B shows a state after the optical sheet is fixed.

In the above-described embodiment, a case in which the guide panel for fixing the edge of the uppermost optical sheet is composed of an upper guide panel and a lower guide panel that are press-fitted or coupled in a hook structure has been exemplified.

However, as in the embodiment of FIG. 9 , a form in which the lower surface of the upper guide panel 532 and the upper surface of the lower guide panel 534 are coupled by an adhesive pad or the like without a protrusion or receiving groove may also be possible.

That is, in the embodiment of FIG. 9 , the guide panel is composed of an upper guide panel 532 having a frame structure having a flat bottom surface and a lower guide panel 534 having a flat top surface, and the uppermost optical sheet 526' A mounting slot is not formed on the edge portion, and the edge portion may be attached between the coupling surfaces of the upper and lower guide panels by means of double-sided tape or adhesive.

As shown in FIG. 9A , a first adhesive member 550 such as double-sided tape is attached to the lower surface of the upper guide panel 532, and the edge of the uppermost optical sheet 526' is adhered to the other surface of the adhesive member.

Meanwhile, the bottom and side surfaces of the lower guide panel 534 are fixed to the inner surface of the cover bottom, and a second adhesive member 550' such as double-sided tape is attached to the upper surface of the lower guide panel 534.

Of course, the height of the upper surface of the lower guide panel 534 is set lower than the height of the lower optical sheet of the backlight unit. That is, the height of S2, which is the bonding surface between the upper guide panel 532 and the lower guide panel 534 and the attachment surface between the edge of the uppermost optical sheet and the guide panel, is lower than the height of the reference surface S2 of the central region of the uppermost optical sheet.

In this state, when the upper guide panel 532 and the lower guide panel 534 are bonded, the edge of the uppermost optical sheet is already fixed to the lower surface of the upper guide panel by the first adhesive member, and the edge of the uppermost optical sheet Since the height of the guide panel attachment surface S2 is lower than the height of the reference surface S2 of the central region of the uppermost optical sheet, the uppermost optical sheet 526' is fixed while receiving downward tension as shown in FIG. 9B.

Therefore, it is possible to have the same effects as those of the first embodiment described in FIG. 4 .

FIG. 10 shows an optical sheet fixing method according to another embodiment of the present invention. FIG. 10A shows a state before the optical sheet is fixed, and FIG. 10B shows a state after the optical sheet is fixed.

Unlike the previous embodiment, in the embodiment of FIG. 10 , a single non-separable guide panel 630 is used instead of a separate guide panel.

That is, a first adhesive member 550 such as double-sided tape is attached to the bottom surface of the single non-separable guide panel 630, and an edge portion of the uppermost optical sheet 626' is adhered to the other surface of the adhesive member.

Meanwhile, a second adhesive member 550' such as a double-sided tape is also attached to the inner surface of the cover bottom 410.

In this state, when the non-separable guide panel 630 is coupled to the cover bottom, the edge of the uppermost optical sheet is already fixed to the lower surface of the non-separable guide panel 630 by the first adhesive member, and the edge of the uppermost optical sheet Since the attachment surface S2 of the non-separable guide panel 630 substantially coincides with the upper surface of the cover bottom, the uppermost optical sheet 626' is fixed while receiving downward tension, as shown in FIG. 10B.

Therefore, it is possible to have the same effects as those of the first embodiment described in FIG. 4 .

11 is a detailed configuration diagram of an optical sheet used in this embodiment, showing an example of one or more lower optical sheets and an uppermost optical sheet disposed thereon.

As shown in FIG. 11 , the optical sheet used in this embodiment may be a combination of multiple optical sheets including one or more lower optical sheets disposed on the light guide plate and an uppermost optical sheet disposed on the lower optical sheet.

11 is an example of an optical sheet assembly according to the present embodiment, in which a diffusion sheet (DS), a light collecting sheet (PS), a reflective polarizing film (DBEF) for improving luminance, or a light collecting sheet (PS) are disposed on a light guide plate. show the case

At this time, the reflective polarizing film (DBEF) or the light collecting sheet (PS) disposed on the uppermost portion becomes the uppermost optical sheet 426', and the diffusion sheet (DS) and the light collecting sheet (PS) disposed on the lower portion are the lowermost optical sheet (426'). It can be expressed as an optical sheet 426.

In this case, only the edge of the uppermost optical sheet 426' is attached to and fixed to the guide panel, and the lower optical sheet 426 may not be attached to the guide panel.

Of course, edges of all of the two or more optical sheets including the uppermost optical sheet may be attached and fixed to the guide panel.

In this way, if only the edge portion of the uppermost optical sheet 426' is attached to and fixed to the guide panel, it is sufficient to change only the structure of the uppermost optical sheet without changing the structure of the lower optical sheet among the plurality of optical sheets. In addition, since the lower optical sheet is partially protected from the influence of heat or external moisture by the uppermost optical sheet, the selection of materials for the lower optical sheet can be widened.

In addition, only the edge portion of the uppermost optical sheet 426' is attached to and fixed to the guide panel, but the material constituting the uppermost optical sheet has a lower coefficient of thermal expansion than the material constituting the lower optical sheet, or the uppermost optical sheet A material constituting the lower optical sheet may have a lower moisture absorption characteristic than a material constituting the lower optical sheet.

For example, materials for optical sheets include polymethyl methacrylate (PMMA), MS (methlystylene) resin, polystyrene (PS), polypropylene (PP), and polyethylene terephthalate (polyethylene terephthalate). PET) and polycarbonate (PC), etc. may be used, and among these materials, the top optical sheet 426' is composed of a material having a low thermal expansion property or a moisture absorption expansion property (moisture absorption property), and a higher thermal expansion property or The remaining lower optical sheet may be made of a material having moisture absorption and expansion characteristics (moisture absorption characteristics).

In this way, since only the uppermost optical sheet 426' is exposed to the outside of the backlight unit and covers and protects components disposed thereunder, the uppermost optical sheet has lower thermal expansion characteristics or moisture absorption characteristics (moisture absorption characteristics) than the lower optical sheet. When configured so as to, there is an advantage in that even when humidity and heat are applied from the outside, deformation due to wrinkles, expansion, and splitting of the uppermost optical sheet is minimized, and components disposed below can be protected from the external environment.

As described above, according to one embodiment of the present invention, the edge of the optical sheet constituting the backlight unit is attached to the bottom surface of the guide panel and fixed, but the height of the attachment surface of the optical sheet and the guide panel is lower than the reference surface of the optical sheet. By placing and fixing the optical sheet with downward tension applied, the optical sheet and its lower parts can be firmly supported, deformation of the optical sheet due to heat or humidity is prevented, and moisture permeation from the outside can be prevented. There is a preventive effect.

In addition, by forming a guide panel supporting the display panel in a vertical split type, fixing the edge of the optical sheet to a coupling part of the upper and lower guide panels, and forming the attachment surface of the upper and lower guide panels to be lower than the reference surface of the optical sheet, The optical sheet may be firmly fixed to the support structure of the display device in a state in which tension is applied.

In addition, by attaching and fixing the edge of the uppermost optical sheet among the plurality of optical sheets disposed on the light guide plate of the backlight unit to the lower surface of the guide panel, the uppermost optical sheet is made of a lower expansion material or a lower moisture absorption material than the rest of the optical sheets, While firmly fixing the optical sheet, display defects due to expansion of the optical sheet due to heat or moisture may be prevented.

The above description and accompanying drawings are merely illustrative of the technical idea of the present invention, and those skilled in the art can combine the configuration within the scope not departing from the essential characteristics of the present invention. , various modifications and variations such as separation, substitution and alteration will be possible. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed according to the claims below, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

410: cover bottom 430, 630: guide panel
432, 532: upper guide panel 434, 534: lower guide panel
422: light guide plate 424: reflector
433: protrusion 435: receiving groove
440: display panel
426', 526', 626': (top) optical sheet
550, 550': 1/2 adhesive member

Claims (9)

display panel;
a guide panel including an upper guide panel and a lower guide panel to support the display panel;
a backlight unit including a light source, a light guide plate transmitting light from the light source, and one or more optical sheets disposed on the light guide plate; and
a cover bottom supporting the guide panel and the backlight unit;
Including,
An edge portion of the optical sheet is attached to and fixed to coupling surfaces of the upper guide panel and the lower guide panel, and an attachment surface of the edge portion and the coupling surface is disposed lower than a reference surface of the central region of the optical sheet, so that the optical sheet A display device that is fixed with tension applied to the seat. delete According to claim 1,
The upper guide panel is provided with a protrusion disposed in the longitudinal direction, and the lower guide panel is provided with a receiving groove in which the protrusion is received and coupled,
A display device comprising a mounting slot into which the protruding portion of the upper guide panel is inserted is provided at an edge of the optical sheet. According to claim 3,
The display device of claim 1 , wherein the protruding portion of the upper guide panel includes a hook portion, and a hook groove into which the hook portion is inserted is disposed in a receiving groove of the lower guide panel. According to claim 1,
The optical sheet includes at least one lower optical sheet and an uppermost optical sheet disposed on the lower optical sheet,
A display device in which only an edge portion of the uppermost optical sheet is attached to and fixed to a lower surface of the guide panel. According to claim 5,
The material constituting the uppermost optical sheet has a lower coefficient of thermal expansion than the material constituting the lower optical sheet. According to claim 5,
A material constituting the uppermost optical sheet has a lower moisture absorption characteristic than a material constituting the lower optical sheet. According to claim 3,
and mounting slots formed on three sides of the edge portion of the optical sheet except for a side where the light source is disposed among four sides constituting the edge portion, into which the protruding portion of the upper guide panel is inserted. According to claim 1,
A display device wherein a first adhesive member is bonded to a bottom surface of the upper guide panel, and a second adhesive member is bonded to an upper surface of the lower guide panel.

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