CN1841445A - Display device - Google Patents

Abstract

The present invention relates to a display device comprising: a display panel displaying an image; a light source unit supplying light to the display panel; and a light guide unit including a light guide portion including: a light source unit adjacent to the light source unit a receiving surface; opposite to the display panel, and guiding light emitted by the light source unit to a light emitting surface of the display panel; forming a side wall portion for receiving a receiving space of the display panel along an edge of the light guide portion; and The light guide portion is fixed to a fixed portion on the display device.

Description

display device

technical field

The present invention relates to a display device, more specifically, to a display device with improved assembly process of a backlight assembly and enhanced brightness to improve light efficiency.

Background technique

Recent advances in semiconductor technology have reduced the size and weight of display devices. Flat display panels for small and lightweight display devices are classified into field emission display (FED) panels, vacuum fluorescent display (VFD) panels, liquid crystal display (LCD) panels, organic light emitting tube display (OLED) panels, and plasma display panels ( PDP). Each of the above-mentioned display panels generally includes a pair of substrates arranged opposite to each other, and the inner space between the substrates is maintained in a high vacuum state.

For example, a liquid crystal display (LCD) device using a liquid crystal display panel has many advantages such as small size, light weight, and low power consumption, and is used in many different information processing devices requiring a display device.

The liquid crystal display device changes the molecular arrangement of the liquid crystal by applying a voltage, which is converted into a change in optical characteristics, such as birefringence, optical rotation, dichroism, and light scattering of the liquid crystal cell, so that the emitted light translates into visual changes. That is to say, the liquid crystal display device is a light-receiving display device that modulates light through liquid crystal cells to display data.

As a light-receiving display device, a liquid crystal display device is supplied with light from a backlight assembly, and displays an image on a liquid crystal display panel. The light source unit of the backlight assembly emits light, which is guided by the light guide plate. The brightness of the light is enhanced by an optical sheet group located on the light guide plate, and then, the light is supplied to the liquid crystal panel.

A conventional backlight assembly includes many components such as a light source unit, a light guide plate, an optical thin layer group, and a mold frame for receiving and supporting the components.

Therefore, due to the complicated process of assembling the backlight assembly, the time of the assembly process increases, increasing the possibility of failure occurring during the assembly process. In addition, when elements forming the backlight assembly are moved or misaligned due to external impact or the like, it is difficult to effectively utilize light emitted from the light source unit. Especially, for example, when a display device has two display panels respectively mounted on the front surface and the rear surface of the device folder, such as a mobile phone, the structure of the backlight assembly is more complicated, and therefore, the above-mentioned problem may become more serious.

In addition, before the light emitted from the light source unit reaches the light guide plate and is guided by the light guide plate, light leakage may occur in the light path, resulting in loss of luminance.

Contents of the invention

The present invention provides a display device capable of improving an assembly process of a backlight assembly and increasing brightness to improve light efficiency.

In the description which follows, additional features of the invention will be set forth, and in part will be obvious from the description, or may be learned by practice of the invention.

The present invention discloses a display device, which includes: a display panel for displaying images; a light source unit for supplying light to the display panel; and a light guide unit including a light guide part including: a light receiving face; opposite to the display panel, and guide the light emitted by the light source unit to the light emitting surface of the display panel; a side wall portion defining a space for receiving the display panel along an edge portion of the light guide portion; and for fixing the Fixed part of the light guide section.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Description of drawings

The accompanying drawings to provide a further understanding of the invention are given here, which constitute a part of this specification, and illustrate embodiments of the invention, and together with the description, serve to explain the principle of the invention:

FIG. 1 is an exploded perspective view showing a display device according to an embodiment of the present invention;

2 is a perspective view showing a coupled state of the light guide unit and the printed circuit board shown in FIG. 1;

Fig. 3 is a schematic diagram showing the path of light passing through the light guide unit shown in Fig. 1;

4 is a perspective view showing a light-shielding film and a light-reflecting film attached to the light guide unit shown in FIG. 1;

5 is a coupled state of a light guide unit, a molding frame, a bottom chassis and a printed circuit board according to another embodiment of the present invention.

Detailed ways

Hereinafter, a display device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, a display device employing twin backlight assemblies, ie, a dual-fold type mobile phone, is schematically shown as an example. The embodiments of the present invention are only intended to illustrate the present invention, and thus the present invention is not limited to these

Example.

Elements that are not relevant to the practice of the present invention are omitted for convenience, and the same reference numerals are used throughout the specification to designate elements that are the same as or similar to each other.

Next, an embodiment of the present invention will be described with reference to FIGS. 1, 2, 3 and 4. FIG.

As shown in FIG. 1 , the display device 10 may include a display panel assembly 200 , and backlight assemblies 300 and 400 respectively providing light to the display panels 210 and 220 . The display device 10 may further include a top chassis 510 , a molding frame 550 and a bottom chassis 520 to fix and/or support the display panel assembly 200 and the backlight assemblies 300 , 400 .

The display panel assembly 200 includes a main board unit 210 , a sub-board unit 220 , a first flexible circuit board 230 , a second flexible circuit board 240 , a printed circuit board 250 , and an integrated circuit chip 260 . The integrated circuit chip 260 is formed in the form of COF (Chip On Film) or TCP (Tape Carrier Package).

Although two board units 210 and 220 are shown in FIG. 1 , the present invention is not limited to two board units 210 and 220 . Two or more plate units may be included, that is to say at least two plate units. Similarly, although two liquid crystal display panels are shown as panel units 210 and 220 in FIG. 1, this is intended to illustrate the panel units employed by the present invention, but the present invention is not limited thereto. Accordingly, one or more liquid crystal display panels may be included, or other light receiving display panels may be used.

The main board unit 210 is larger than the sub board unit 220 opposite to the main board unit 210 . The display device 10 may especially be used on a folder-type or clamshell-type mobile phone in which the main board unit 210 is provided on the inner surface of the folder and the sub-board unit 220 is provided on the outer surface of the folder. Therefore, when the folding part of the folding device is closed, a relatively small amount of information such as time can be displayed in the sub-board unit 220 having a small screen size; A relatively large amount of information is displayed in the motherboard unit 210 of the size.

Next, the internal structure of the motherboard unit 210 using a liquid crystal display panel will be described. Since the structure of the sub-board unit 220 is substantially equivalent to that of the main board unit 210, a detailed description of the sub-board unit 220 is omitted.

The motherboard unit 210 includes: a first TFT board 211 on which a plurality of thin film transistors (TFTs) are formed; a first color filter board 212 opposite to the first TFT board 211; liquid crystal (not shown). Although not shown in the illustration, a polarizing plate is installed on the front of the first color filter plate 212 and the rear of the first TFT plate 211 so that the polarizing plate linearly polarizes visible light provided from the backlight assembly 300 .

The first TFT plate 211 includes: a plurality of gate lines and data lines in a matrix shape formed on a transparent insulating substrate (not shown); formed between the gate lines and data lines (not shown) a thin film transistor at the cross point of the thin film transistor; and a pixel electrode coupled with the thin film transistor and made of a transparent conductive material such as ITO (Indium Tin Oxide). In a thin film transistor, a source terminal is connected to a data line, a gate terminal is connected to a gate line, and a drain terminal is connected to a pixel electrode.

Accordingly, signal data is transferred from the printed circuit board 250 to the gate and data lines of the main board unit 210 through the first flexible circuit board 230 and input to the source and gate terminals of the thin film transistor. According to the signal data, the thin film transistor is turned on and off, thereby switching the pixel electrode connected to its drain terminal.

The first color filter plate 212 is opposite to the first TFT plate 211 and disposed on it. In a non-limiting example, the first color filter plate 212 may be a plate: pixels with three primary colors are formed on the first color filter plate 212, for example, red, green, blue, or cyan, magenta, yellow. , as color pixels that display a predetermined color when transmitting light, and a common electrode made of ITO is formed on the entire surface of the first color filter plate 212 . Therefore, when the thin film transistor as the switching element is turned on, an electric field is formed between the pixel electrode and the common electrode. The alignment angle of the liquid crystal molecules provided between the first TFT plate 211 and the first color filter plate 212 is changed due to the electric field, and thus, a desired image change in light transmittance is obtained due to the change in the alignment angle.

In order to control the alignment angle of the liquid crystal molecules and the alignment time of the liquid crystal molecules, driving signals and timing signals are provided to the gate lines and the data lines of the first TFT panel 211 . The integrated circuit chip 260 is located or mounted on the first TFT board 211, and may be covered with a protective film. A drive signal is supplied from the printed circuit board 250 to the integrated circuit chip 260 through the flexible circuit board 230, and a data drive signal and a gate drive signal for driving the main board unit 210 are generated, as well as a plurality of timing signals for supplying the signal at an appropriate time. , and transmit the gate driving signal and the data driving signal to the gate line and the data line of the motherboard unit 210 respectively.

The sub-board unit 220 includes a second TFT board 221 and a second color filter board 222 , and receives a driving signal provided by the printed circuit board 250 through another integrated circuit chip (not shown) through the second flexible circuit board 240 .

A plurality of ohmic elements 255 for supplying signals to the first flexible circuit board 230 and the second flexible circuit board 240 are mounted on the printed circuit board 250, and an external connector such as a mobile phone connector 256 is mounted at an end thereof. . A signal indicating the degree or angle of opening and closing of the window of the folding portion is provided to the first flexible circuit board 230 through the mobile phone connector 256 . The first flexible circuit board 230 is connected to the main board unit 210 with a printed circuit board. Although the first flexible circuit board 230 is cut away in FIG. 1 for convenience, the first flexible circuit board 230 is connected with the main board unit 210 to form a main body.

The backlight assembly includes a first backlight assembly 300 and a second backlight assembly 400 which provide light emitted from the light source units 310 and 410 to the main board unit 210 and the sub-board unit 220, respectively, and which are The mainboard unit 210 and the subboard unit 220 are in contact with each other. According to the above-described embodiment of the present invention shown in FIG. 1 , the first backlight assembly 300 is accommodated or disposed in the molding frame 550 , and the second backlight assembly 400 is mounted on and coupled to the printed circuit board 250 .

The first backlight assembly 300 includes: a first light source unit 310 that provides light to the motherboard unit 210; a light guide plate 320 that guides the light emitted from the light source unit 310; a reflective thin layer 340 that reflects light; brightness, and provide the light to the first optical thin layer group 330 of the motherboard unit 210; and a molding frame that accommodates and supports at least the components of the first backlight assembly 300 described above.

Although FIG. 1 shows a light emitting diode (LED) positioned or installed on the flexible board 312 as the first light source unit 310, this is only an example of the first light source and the present invention is not limited thereto. Therefore, other light sources may also be used as the first light source unit 310, such as lamps. In addition, a line light source and a surface light source having the light-emitting diodes 311 in modules can also be used. Although three light emitting diodes 311 are shown in FIG. 4 , it should be understood that the present invention is not limited thereto, and the number of light emitting diodes 311 can be set as required. The flexible board 312 is connected to the printed circuit board 250 and provides light source control signals to drive the first light source unit 310 .

The first optical thin layer group 330 includes a diffusing thin layer and a prism thin layer, and the diffusing thin layer is used to diffuse the light to improve the uniformity of the light, so that the light traveling toward the motherboard unit 210 will not be partially concentrated in the light guide plate 320 to Spots are formed in the main board unit 210, and the prism thin layer is used to improve brightness by causing light passing through the diffusion thin layer to pass through the main board unit in a vertical direction. The first set of optical lamellae 330 may further include a protective lamina that protects the diffusion and prism lamina that are sensitive to dust, scratches, or other contaminants, and prevents the introduction of particles.

The reflective thin layer 340 reduces light loss and helps light to diffuse by reflecting light emitted in the opposite direction of the main board unit 210 through the light guide plate 320 and toward the light guide plate 320 again, thereby improving light transmission to the main board unit 210. Uniformity.

The molding frame 550 accommodates and supports the first light source unit 310 , the light guide plate 320 , the reflective thin layer 340 and the first optical thin layer group 330 , and accommodates and supports the main board unit 210 therewith. A top frame 510 and a bottom frame 520 are respectively provided at the top and bottom of the forming frame 550 to accommodate the above-mentioned components. The top and bottom of the forming frame 550 are coupled to each other at the sides of the forming frame 550 .

The second backlight assembly 400 includes a second light source unit 410 that provides light to the sub-board unit 220; and a light guide unit 420 that is coupled to the printed circuit board 250 and guides light emitted from the second light source 410 to the sub-board unit 220 , which accommodates and supports the second optical thin layer group 430 and the sub-board unit 220 . The second backlight assembly 400 may further include a reflective plate 440 provided between the light guide unit 420 and the printed circuit board 250 . The printed circuit board is directly coupled with the light guide unit 420 and disposed under the chassis 520 .

A coupling hole 251 , which is coupled to the light guide unit 420 , may be formed in a predetermined position of the printed circuit board 250 . The reflection plate 440 is installed on at least a part of the printed circuit board 250 , which is coupled to the light guide unit 420 . The reflection plate 440 may be installed on the printed circuit board 250 according to various techniques, such as using double-sided tape or adhesive.

The second light source unit 410 may be directly mounted on the surface of the printed circuit board 250 connected to the light guide unit 420 . The second light source unit 410 includes a light emitting diode, which can be directly mounted on the printed circuit board 250 by soldering technology.

The reflective film 253 is formed on the peripheral area of the second light source unit 410 on the printed circuit board 250 . For example, the reflective film 253 may be formed by silk coating. Also, the reflective film 253 may be made of a material including silver (Ag) paste. Since the reflective film 253 is white or silver, the reflective film 253 reflects light. When the light emitted by the second light source unit 410 is provided to the sub-board unit 220 through the light guide unit 420 , the reflective film 253 can prevent possible loss of light. Specifically, the reflective film 253 may prevent light loss that may occur before the light emitted from the second light source 410 reaches the position where the reflective plate 440 is formed.

Therefore, according to an embodiment of the present invention, since the second light source unit 410 in the display device 10 is directly mounted or attached to the printed circuit board 250, an assembly process may be simplified. Therefore, the reflective film 253 is formed on the printed circuit board 250 to prevent the light emitted from the second light source unit 410 from being lost in the light path before reaching the reflective plate 440 . For example, until light is guided through the light guide unit 420, maximum brightness may be improved or increased to maximize light efficiency.

As shown in FIG. 2 , the light guide unit 420 includes: a light guide portion 421 having a light receiving surface opposite to the second light source unit 410 and a light emitting surface opposite to the sub-board unit 220 (see FIG. 1 ), the light guide portion 421 The light emitted from the second light source unit 410 is guided to the sub-board unit 220; the side wall portion 422 extends integrally to the sub-board unit 220 along the edge of the light guide portion 421, and forms a second optical thin layer group 430 (see FIG. 1) and the accommodating space of the sub-board unit 220 ; and the fixing portion 423 for fixing the light guide portion 421 . According to a non-limiting example of the present invention, the fixing part 423 is in the shape of a square column, which is inserted into the engaging hole 251 of the conductive printed circuit board 250 . For example, the light guide unit 420 may be composed of a material including polymethyl methacrylate (PMMA) or polycarbonate (PC), which is not easily deformed or broken due to its high strength and high light transmittance.

The light guide unit 421 includes: one or more grooves 425 formed along the edge of the light emitting surface for preventing light leakage; and receiving grooves 424 formed in the light receiving surface to receive at least a portion of the second light source unit 410 . A groove 425 for preventing light leakage may be formed in the light guide part 421 in a direction perpendicular to the light emitting surface 426 by a method of punching or pressing the light guide part 421 .

As shown in FIG. 3, the groove 425 prevents light leakage, specifically, prevents light supplied to the light guide portion 421 from the second light source unit 410 from leaking from the side of the light guide portion 421 according to Snell's Law, thereby enabling As much light as possible is emitted from the light emitting surface 426 . For example, Snell's law states that when light travels from a medium with a larger refractive index to a medium with a smaller refractive index, all light can be reflected and no refracted light will be produced. That is to say, when the light leakage prevention groove 425 is formed along the edge portion of the light emitting surface 426 of the light guide portion 421, the light emitted to the side of the light guide portion 421 contacts the air in the light leakage prevention groove 425, and the refraction of the air The index is smaller than the refractive index of the light guide portion 421, the light does not leak to the outside, for example, the light is reflected to the light guide portion 421 substantially completely. Therefore, it should be understood that the reflection loss corresponds to the refractive index.

The light guide part 421 has a predetermined pattern formed on a part of the opposite surface of the light emitting surface 426 , which is separated from the second light source unit 410 by a predetermined distance. That is, the pattern is not formed on a part of the opposite surface of the light emitting surface 426 close to the second light source unit 410 . The length of the portion of the opposite surface of the light-emitting surface 426 on which no pattern is formed is set so that light entering the light-receiving surface is uniformly scattered in the light-guiding portion 421 according to Snell's law.

The light guide unit 420 according to the embodiment of the present invention discussed above and shown in FIG. The optical thin layer group 430 can be fixed or attached to the printed circuit board 250 . In addition, a groove 425 for preventing light leakage is formed in the light guide unit 420, and the groove 425 can prevent loss of light, thereby improving a brightness level.

As shown in FIG. 4 , the light shielding film 428 may be arranged or formed along the edges of the second optical thin layer group 430 and the light guide portion 421 which are accommodated or disposed by the side walls. In the accommodation space formed by the portion 422 , and a reflective film 429 may be provided on one or more side surfaces among the sides of the light guide unit 420 except for the light emitting surface 426 of the light guide portion 421 . For example, a reflective film pattern can be printed instead of using a reflective film.

The light shielding film 428 and the reflective film 429 can prevent light from leaking from the surroundings of the light guide unit 420, thereby reducing light loss. The light shielding film 428 may be made of a material including a pressure sensitive adhesive (PSA), thereby preventing loosening of the second optical thin layer group 430 accommodated in the accommodation space of the light guide unit 420 .

The second optical thin layer group 430 may have substantially the same structure as the first optical thin layer group 330 of the first backlight assembly 300 described above. The reflective plate 440 may be directly provided on the printed circuit board 250 , unlike the reflective sheet 340 of the first backlight assembly 300 , and has substantially the same operational advantages as the reflective sheet 340 .

Next, another embodiment of the present invention will be described with reference to FIG. 5 .

As shown in FIG. 5, in a non-limiting embodiment of the present invention, the display device 10 includes: a light guide unit 420 having a hook-shaped fixing portion 423; frame 550. The fixing part 423 of the light guide unit 420 includes: a protrusion part 423 a extending from the side wall part 422 in a direction parallel to the light guide unit 420 ; and a hook part 423 b bent from the protrusion part 423 a toward the molding frame 550 .

Between the molding frame 550 and the light guide unit 420 are provided the printed circuit board 250 and the chassis 520 area, both of which have formed perforated grooves 251 and 521, so that the fixing portion 423 of the light guide unit 420 can be fixed or attached to the molding frame, respectively. 550 fastening groove 555 . By coupling the molding frame 550 with the light guide unit 420 , the bottom chassis 520 and the printed circuit board 250 disposed therebetween are coupled with the molding frame 550 and the light guide unit 420 . Similar to the first embodiment, the reflective plate 440 may be installed on at least a part of the printed circuit board 250 coupled with the light guide unit 420 , and form a reflective film 253 to surround the second light source 410 .

Therefore, the light guide unit 420 that guides the light emitted from the second light source unit 410 to the sub-board unit 220 and accommodates and supports the sub-board unit 220 and the second optical sheet may be fixed or attached to the molding frame 550. Group 430. In addition, the molding frame 550, the bottom chassis 520, the printed circuit board 250, and the light guide unit 420 may be coupled together.

Although the description and illustration of the structure of the light guide unit are only given for the application in the second backlight assembly, the purpose is to illustrate the structure and layout of the display device according to the present invention, and the present invention is not limited to these Example. Therefore, the structure of the light guide unit according to the present invention can be applied to the first backlight assembly, and the structure and layout of the display device can be modified in various forms.

As described above, in the display device according to the present invention, the display panel and the optical thin layer group can be stable and sufficiently supported while guiding light from the light source unit to the display panel. In addition, display panels and optical laminates can be easily coupled with printed circuit boards and molding frames. In addition, the grooves to prevent light leakage can reduce light loss, thereby enhancing brightness.

In addition, since the reflective film may be formed on or directly on the printed circuit board surrounding the light source unit, it is possible to prevent light emitted from the light source unit from being lost before reaching the reflective plate, thereby maximizing light efficiency.

Various modifications and changes in the present invention will be apparent to those skilled in the art without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

Claims (17)

1. A display device comprising: display board, displaying images; a light source unit providing light to the display panel; and The light guide unit includes a light guide part, and the light guide part includes: a light receiving surface disposed adjacent to the light source unit; a light emitting surface, opposite to the display panel, and guiding the light emitted from the light source unit to the display panel; a side wall portion defining a space for accommodating the display panel; and A fixing member fixes the light guide part to the display device. 2. The display device according to claim 1, wherein the light guide unit further comprises: A light leakage preventing groove is formed along at least one edge portion of the light emitting surface. 3. The display device according to claim 1, wherein the light guide unit further comprises: The accommodation groove provided in the light receiving surface is used to accommodate at least a part of the light source unit. 4. The display device according to claim 1, wherein a pattern is formed on the light emitting surface. 5. The display device according to claim 1, further comprising: a set of optical lamellae housed in the space formed by said side wall portion, Wherein, a light shielding film is provided along edge portions of the light guide unit and the optical thin layer group. 6. The display device of claim 1, wherein a reflective film is provided along one of sides of the light guide unit except for a light emitting surface of the light guide part. 7. The display device according to claim 1, further comprising: The printed circuit board transmits the driving signal to the display board. 8. The display device of claim 7, wherein the printed circuit board comprises: fastening groove, Wherein, the fixing part of the light guide unit is fastened. 9. The display device according to claim 8, further comprising: A reflection plate is provided on the light guide unit. 10. The display device of claim 7, wherein the light source unit is directly provided on the printed circuit board. 11. The display device of claim 10, further comprising: A reflective film surrounding the light source unit. 12. The display device of claim 11, wherein the reflective film is formed by screen coating. 13. The display device of claim 11, wherein the reflective film comprises silver paste. 14. The display device of claim 1, further comprising: a molding frame, coupled with the light guide unit, having a fastening groove formed therein, Wherein, the fixing part of the light guide unit is fastened to the fastening groove. 15. The display device according to claim 14, wherein the fixing part comprises: A portion extending from the sidewall portion in a direction generally parallel to the light guide portion. Another portion bent from the protruding portion toward the forming frame. 16. The display device of claim 14, further comprising: a printed circuit board provided between the light guide unit and the mold frame, and coupled with the light guide unit and the molding frame; and A reflection plate is provided on at least a part of the printed circuit board coupled with the light guide unit. 17. The display device of claim 1, wherein the light source unit comprises a light emitting diode.

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