KR20080018503A - Display apparatus - Google Patents

Abstract

A display apparatus is provided to convert ultraviolet rays into visible rays through an auxiliary film to reduce a total amount of ultraviolet rays so as to reduce photochemistry reaction by ultraviolet rays and damage of parts exposed to ultraviolet rays, thereby increasing durability. A display panel displays images. A light emitting unit is mounted under the display panel for generating light to supply the light to the display panel. An optical film(200) is formed between the display panel and the light emitting unit and has an auxiliary material(1) absorbing the light and converting wavelength thereof to emit the light. The optical film includes the auxiliary material inside or has an auxiliary film(10) having the auxiliary material applied at an upper side or a lower side of the optical film.

Description

Display device {DISPLAY APPARATUS}

1 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 2 is a detailed view of the display panel of FIG. 1.

3 is a detailed view of the light emitting unit of FIG. 1.

4 is a detailed view of the optical film of FIG. 1.

5A and 5B are cross-sectional views illustrating the optical film structure of FIG. 4 in accordance with different embodiments of the present invention.

* Description of the symbols for the main parts of the drawings *

100-Light emitting unit 110-Light emitting unit

120-LGP 130-Reflector

140-Storage Container 200-Optical Film

210-Diffusion Sheet 220-Prism Sheet

300-display panel 310-first substrate

320-second substrate

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to a display device in which a lifespan is increased and a high brightness image is displayed.

The display device includes a display panel that displays an image and a light emitting unit that generates light and provides the light to the display panel. The light includes visible light, and an image is displayed using the visible light. On the other hand, in addition to the visible light, the light has various wavelengths, and includes, for example, ultraviolet light having a wavelength shorter than that of the visible light.

The ultraviolet light is not visible but strong chemical action, causing a photochemical reaction or sterilization. By the chemical action, components installed on the path through which the ultraviolet light passes may be deformed.

In particular, the display device may include an optical film having various functions between the display panel and the light emitting unit so that the light is uniformly provided to the display panel, and the optical film is affected by the ultraviolet rays. Performance deteriorates and shortens life. In addition, the light is reduced while passing through the optical film, thereby lowering the brightness of the display device.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a display device in which a lifetime is increased and an image of high brightness is displayed.

The display device according to the exemplary embodiment of the present invention includes a display panel, a light emitting unit, and an optical film. The display panel displays an image. The light emitting unit is mounted under the display panel to generate light and provide the light to the display panel. The optical film is formed between the display panel and the light emitting unit, and includes an optical film having an auxiliary material that absorbs the light and converts and emits the light.

In the above display device, the optical film includes the auxiliary material therein or an auxiliary film coated with the auxiliary material on at least one of an upper surface and a lower surface of the optical film.

In the display device, the light includes ultraviolet rays, and the auxiliary material converts the ultraviolet rays into visible light and emits the same. Alternatively, the light includes ultraviolet rays and visible light, and the auxiliary material absorbs light having a wavelength of 200-600 nm and converts the light into 400-700 nm.

In the display device, the auxiliary material may be a fluorescent material or a phosphorescent material.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be applied and modified in various forms. Rather, the following embodiments are provided to clarify the technical spirit disclosed by the present invention, and furthermore, to fully convey the technical spirit of the present invention to those skilled in the art having an average knowledge in the field to which the present invention belongs. Therefore, the scope of the present invention should not be construed as limited by the embodiments described below.

In addition, in the drawings presented with the following examples, the size of each region is simplified or somewhat exaggerated to emphasize a clear description, the same reference numerals in the drawings represent the same components.

In addition, the "first / second" or "top / bottom" mentioned in the following examples are used as a relative concept. The term 'first / second' is used to distinguish different components from each other. The term 'top / bottom' may change the 'top' to 'bottom' and 'bottom' to 'top' according to the rotation of the components or the viewing angle of the observer.

1 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, a light emitting unit 100, an optical film 200, and a display panel 300 are provided. The display panel 300 has a rectangular planar shape and an image is displayed through one surface of the display panel 300. The light emitting unit 100 generates light and provides the light to the display panel 300 so that the image can be displayed. The light emitting unit 100 is attached to an opposite surface on which the image is displayed on the display panel 300. For example, the light emitting unit 100 is attached to the lower surface of the display panel 300, and an image is displayed in the direction of the upper surface of the display panel 300. The optical film 200 is formed between the display panel 300 and the light emitting unit 100 to play an auxiliary role to display a high quality image.

Hereinafter, each of the display panel 300, the light emitting unit 100, and the optical film 200 will be described in detail with reference to the drawings.

FIG. 2 is a detailed view of the display panel of FIG. 1.

Referring to FIG. 2, the display panel 300 includes a first substrate 310 and a second substrate 320. The gate line 311, the data line 312, the thin film transistor 313, and the pixel electrode 314 are formed on the first substrate 310. The gate line 311 and the data line 312 are formed in plural, and cross each other insulated from each other. Regions that are divided while the plurality of gate lines 311 and the data line 312 cross each other correspond to pixel regions. The pixel area represents a minimum unit in which an image is displayed, and all pixel areas have the same structure.

The thin film transistor 313 and the pixel electrode 314 are formed in the pixel region. The thin film transistor 313 has a control electrode, an input electrode, and an output electrode connected to the gate line 311, the data line 312, and the pixel electrode 314, respectively.

The light blocking film pattern 321, the color filter 322, and the common electrode 323 are formed on the second substrate 320. The light blocking film pattern 321 is formed to correspond to the boundary of the pixel area, and blocks light transmission in the corresponding area. The color filter 322 is formed on the light blocking film pattern 321 and displays a color image according to a combination of red (R), green (G), and blue (B) corresponding to three primary colors of light. The common electrode 323 is formed on the color filter 322 to face the pixel electrode 314.

A liquid crystal layer (not shown) having a liquid crystal is formed between the first and second substrates 310 and 320. In operation of the liquid crystal display, a signal is transmitted to the gate line 311 and the data line 312, and a data voltage is applied to the pixel electrode 314 by the signal. At the same time, a common common voltage is applied to the common electrode 323, and an electric field is formed in the liquid crystal layer due to the difference between the data voltage and the common voltage.

The liquid crystal constituting the liquid crystal layer has dielectric anisotropy, and the arrangement direction thereof changes according to the electric field. In addition, the liquid crystal has refractive index anisotropy, and transmittance with respect to light varies depending on the arrangement direction. Therefore, when the electric field is applied, an image corresponding to the arrangement of the liquid crystal is displayed.

3 is a detailed view of the light emitting unit of FIG. 1.

Referring to FIG. 3, the light emitting unit 100 includes a light emitting unit 110, a light guide plate 120, a reflecting plate 130, and a storage container 140. The light emitting unit 110 has a structure in which a plurality of light sources are separated into dots. The light source may be configured as a light emitting diode (LED). The light emitting diode generates carriers (electrons and holes) using a p-n junction structure of a semiconductor, and generates light as the carriers recombine.

The light guide plate 120 is formed on the side surface of the light emitting unit 110, and guides the light generated by the light emitting unit 110 to the display panel 300. The light guide plate 120 has a size corresponding to the display panel 300. The light guide plate 120 is formed to have a constant thickness and has an entrance surface 121 / an emission surface 122 / a reflection surface 123. The incident surface 121 is positioned adjacent to the light emitting unit 110, and the light from the light emitting unit 110 is incident on the light guide plate 120 through the incident surface 121. The emission surface 122 is formed by extending an upper side of the incident surface 121, and the incident light is emitted to the display panel 300 through the emission surface 122. The reflection surface 123 faces the emission surface 122, and the incident light is reflected to the emission surface 122 through the reflection surface 123.

The reflective plate 130 is formed at a lower portion of the light guide plate 120 to correspond to the reflective surface 123, and reflects light passing through the reflective surface 123 toward the light guide plate 120 to improve light efficiency. do.

The storage container 140 has a rectangular planar shape corresponding to the reflecting plate 130. The storage container 140 has an upper surface open to form an accommodation space therein, and the light emitting unit 110, the light guide plate 120, and the reflective plate 130 are accommodated in the storage space.

In FIG. 3, an edge type structure in which the light emitting unit 110 is disposed on the side of the display panel 300 in a plan view is shown. However, a direct type structure in which the light emitter 110 is disposed on the lower surface of the display panel 300 in a plane may be applied. In addition, various light sources such as a fluorescent lamp may be applied to the light source of the light emitting unit 110 in addition to the light emitting diode.

4 is a detailed view of the optical film of FIG. 1.

Referring to FIG. 4, the optical film 200 has a size corresponding to the exit surface 122 of the light guide plate 120 and includes a diffusion film 210 and a prism film 220. The diffusion film 210 diffuses the light emitted from the light guide plate 120 to uniformly spread the light to the entire area of the display panel 300.

The prism film 220 may be provided in plural or more. The prism film 220 collects light emitted from the light guide plate 120 in a direction perpendicular to the display panel 300 by using a refractive phenomenon and emits the light. A direction perpendicular to the display panel 300 corresponds to a front direction in which the user views the liquid crystal display, and visibility of the front of the liquid crystal display is improved by the prism film 220.

The optical film 200 includes an auxiliary material. The auxiliary material increases the lifespan and luminance of the liquid crystal display. Hereinafter, the operation of the auxiliary material will be described with reference to the accompanying drawings.

5A and 5B are cross-sectional views illustrating the optical film structure of FIG. 4 in accordance with different embodiments of the present invention.

Referring to FIG. 5A, auxiliary films 10 are formed on upper and lower surfaces of the optical film 200. The auxiliary film 10 may be formed on at least one of the upper surface and the lower surface, and may not necessarily be formed on both surfaces of the optical film 200.

The auxiliary film 10 is made of an auxiliary material 1. The auxiliary material 1 absorbs the light generated by the light emitting unit 100 (arrow mark), converts its wavelength, and then emits the light. As the auxiliary material 1, a fluorescent material or a phosphorescent material may be used.

The fluorescent material is stimulated by light to emit light. The physical process of generating fluorescence is described as a phenomenon in which a fluorescent material absorbing light energy radiates part of it as light energy again. Since the radiated light has less energy than the light stimulating the fluorescent material, the wavelength is longer.

The phosphor is also stimulated by light to emit light similarly to the fluorescent material. However, fluorescence disappears when the stimulating light is removed, whereas phosphorescence generates light for a long time even after the light is removed. This is because fluorescence occurs when the electrons in the fluorescent material absorbing the light enter the ground state in the excited state, but phosphorescence occurs when the phosphor is in the intermediate state and then returns to the ground state in the excited state.

By converting the wavelength of the light generated by the light emitting unit 100 using the auxiliary film 10 as described above has the following advantages. The light has various wavelengths and includes visible light and ultraviolet light. The visible light is used to display an image, but the ultraviolet light cannot be used to display an image because it is invisible to the eye. However, when the auxiliary film 10 is used, ultraviolet rays may be converted into visible light. Therefore, compared with the related art, the amount of light used to display an image is increased, thereby improving luminance.

In general, ultraviolet rays may cause photochemical reactions and damage components of a display device exposed to ultraviolet rays. By the way, when the auxiliary film 10 is used, ultraviolet rays are converted into visible light and the total amount of ultraviolet rays is reduced. Therefore, the photochemical reaction by the ultraviolet rays is reduced, and the parts exposed to the ultraviolet rays can be prevented from being damaged and the life thereof can be extended.

On the other hand, when the auxiliary film 10 is used, color light having a shorter wavelength in visible light may be converted into color light having a longer wavelength. For example, when the red light needs to be provided to the display panel 300 of the liquid crystal display, the auxiliary film 10 may provide the red light to the display panel 300 using the blue light.

As the auxiliary material 1 included in the auxiliary film 10, both organic and inorganic materials may be used. For example, polyfluorene-based, polyparaphenylene-based, polyparaphenylene-vinylene-based high molecular materials, those containing heavy metals in sulfides or zinc sulfides of alkaline earth metals can be used.

The polymer material may adjust the optical wavelength before and after the conversion by adjusting the conjugation length. For example, the polyfluorene-based polymer material may absorb 300-400 nm light to emit blue light, green light or red light. As described above, the color of the light to be provided to the display panel 300 may be adjusted by adjusting the components of the auxiliary material 1. In the liquid crystal display device, it is generally preferable to absorb light having a wavelength of 200-600 nm including ultraviolet rays to emit light having a wavelength of 400-700 nm.

Referring to FIG. 5B, the optical film 200 is formed in a state in which the auxiliary material 1 is mixed therein without a separate auxiliary film 10. For example, the optical film 200 can be manufactured by the method of injection in the state in which the constituent material and the auxiliary material 1 are mixed. The auxiliary material 1 serves to reduce the amount of ultraviolet light generated by the light emitting unit 100 or to absorb and convert the light into light having a desired wavelength range. In addition, the auxiliary material 1 serves to protect the optical film 200 as described below.

Table 1 below shows the material of the optical film and the resulting optical properties.

Referring to Table 1, at least one of polyester, polystyrene, polyethylene, polypropylene, polyvinyl chloride, polycarbonate, polyamide, and polymethyl methacrylate may be used as a constituent material of the optical film 200. In Table 1, the wavelength indicates a specific range in which the above-described constituent materials can absorb and decompose light.

For example, as shown in Table 1, polymethylmethacrylate is vulnerable to light of 290-315 nm wavelength. In the liquid crystal display device, the optical film 200 of the polymethyl methacrylate component and the light of the wavelength of 290 to 315 nm are used together. Therefore, the polymethyl methacrylate component may be decomposed and damaged, and the auxiliary material 1 is used to prevent this. That is, the auxiliary material 1 may reduce the amount of light absorbed by the polymethyl methacrylate polymer by absorbing light passing through the optical film 200 instead.

In order to sufficiently generate light absorption by the auxiliary material 1, the auxiliary material 1 may be included in the optical film 200 in a predetermined amount or more. For example, the auxiliary material (1) is at least ¹⁰ preferably comprises at least ⁸ mol.

The effect of preventing photolysis by the auxiliary material 1 may also be applied to the salping embodiment with reference to FIG. 5A. However, in the embodiment of FIG. 5A, the auxiliary film 10 is formed on the lower surface of the optical film 200 so that the light may be absorbed from the auxiliary film 10 before the optical film 200. desirable.

While some embodiments have been described in terms of examples above, those skilled in the art will appreciate that various modifications can be made without departing from the spirit and scope of the invention as set forth in the claims below. And can be changed.

According to the above embodiments, the lifespan of the display device is increased and an image of high brightness is displayed.

Claims (10)

A display panel on which an image is displayed; A light emitting unit mounted under the display panel and configured to generate light and provide the light to the display panel; And And an optical film formed between the display panel and the light emitting unit and having an auxiliary material that absorbs the light and converts and emits the light. The method of claim 1, The optical film may include the auxiliary material therein. The method of claim 1, The optical film is a display device, characterized in that the auxiliary film coated with the auxiliary material is formed on at least one of the upper surface and the lower surface. The method of claim 1, The light includes ultraviolet light, and the auxiliary material converts the ultraviolet light into visible light and emits the light. The method of claim 1, The light includes ultraviolet rays and visible light, and the auxiliary material absorbs light having a wavelength of 200-600 nm, converts the light into 400-700 nm, and emits the light. The method of claim 1, And the auxiliary material is a fluorescent material. The method of claim 1, And the auxiliary material is a phosphor. The method of claim 1, And the auxiliary material includes at least one of polyfluorene, polyparaphenylene, and polyparaphenylenevinylene. The method of claim 1, And the optical film comprises at least one of polyester, polystyrene, polyethylene, polypropylene, polyvinylchloride, polycarbonate, polyamide, and polymethyl methacrylate. The method of claim 1, The display panel, First and second substrates facing each other; And And a liquid crystal layer interposed between the first and second substrates.

Images