Patent Application
20070247566
Exemplary embodiments of the present invention can be understood in more detail from the following descriptions taken in conjunction with the accompanying drawings, in which:
a and 3b are graphical views showing a wire grid polarizing plate o
a to 4d are graphical views showing a method of manufacturing a light reflecting layer of the wire grid polarizing plate according to an exemplary embodiment of the present invention;
a to 6d are graphical views showing a method of manufacturing a light reflecting layer of the wire grid polarizing plate according to an exemplary embodiment of the present invention;
a and 11b are cross-sectional view illustrating a location of lower retardation films of
Exemplary embodiments of the invention are described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
Referring to
The backlight unit 130 comprises a light source unit 132: a diffusing sheet 136 diffusing light coming from the light source unit 132, and a reflecting sheet 134 formed below the lower portion of the light source unit 132.
The light source unit 132 may be a cold cathode fluorescent tamp (CCFL) or an external electrode fluorescent tamp (EEFL). The light source unit 132 generates light and emits the light toward the diffusing sheet 136.
The reflecting sheet 134 is formed of a material with a high reflectivity and reflects the light proceeding in an opposing direction against the diffusion sheet 136 toward the diffusing sheet 136, and thus the reflecting sheet 134 may reduce a loss of light.
The diffusing sheet 136 directs the light incident from the light source unit 132 to the front surface of the LCD panel 100 and diffuses the light so as to uniformly distribute the light. Then, the diffusing sheet 136 delivers the uniformly diffused light to the LCD panel 100. The diffusing sheet 136 may be a film formed of a transparent resin coated with a member for light diffusion on both sides of the transparent resin.
The LCD panel 100 comprises a thin film transistor (TFT) substrate 106, a countering substrate 104 facing the TFT substrate 106 a liquid crystal layer 102 interposed between the countering substrate 104 and the TFT substrate 106, upper and tower retardation films 108, 110 attached to the outer surfaces of the countering substrate 104 and the TFT substrate 106, respectively, and a film type polarizer 112 attached to the whole surface of the upper retardation film 108.
The countering substrate 104 may comprise a black matrix (BM) preventing light leakage, a plurality of color filters, a common electrode and an upper alignment layer deposited on the common electrode for alignment of the liquid crystal layer.
The TFT substrate 106 is provided with a TFT array (not shown) comprising a plurality of gate lines, a plurality of data lines intersecting the gate lines, a plurality of TFTs formed at an intersected portion of each of the data lines and each of the gate lines, a plurality of pixel electrodes connected to the TFT, and a lower alignment layer deposited on the pixel electrodes for alignment of the liquid crystal layer.
The upper and lower phase difference films 108, 110 are attached to the countering substrate 104 and the TFT substrate 106, respectively, so as to compensate phase difference resulting from a difference of a polarization of the liquid crystal layer in accordance with a variation of a viewing angle caused by birefringence.
The film type polarizer 112 is preferably an iodine-based film. The polarizer 112 transmits light parallel with its own transmission axis and reflects light perpendicular to the transmission axis. The polarizer 112 has a polarizing direction perpendicular to that of the wire grid polarizing plate 120 when the liquid crystal layer 102 is a TN mode (i.e. a twisted angle of 90°).
As shown in
Referring to
The transparent substrate 122 may be formed of a material for example, a glass.
The light reflecting layer 124 may be formed on the transparent substrate 122 in one type of stripe, curve, chevron, or matrix, etc. using a metal that may include, for example, Al, Cr, Mo, Ag, Cu and/or Au or an opaque polymer material. The light reflecting layers 124 are spaced apart from each other with a transmission hole 126 disposed therebetween. At this time, the transmission hole 126 is formed with a width of about 100˜300 nm, preferably, 120 nm, less than the wavelength of a blue color being a minimum wavelength in a range of a visible ray. The light reflecting layer 124 is formed with the same width as that of the transmission hole 126. Alternatively, the light reflecting layer 124 is formed with a width more than that of the transmission hole 126 by about 20%. Further, an insulating film 128 may be formed for covering the light reflecting layer 124 as shown in
The light reflecting layer 124 is formed by a photolithography method, a printing method, or a laser radiation method suitable for a micro process.
A method of manufacturing the light reflecting layer 124 using a laser radiation method will be described with reference to
Referring to
In this way, a plurality of the light reflecting layers 124 may be formed on the transparent substrate 122 by repeating the above process.
Referring to
The laser light source unit 152 generates a laser light by means of amplification and oscillation using emission phenomenon of inner energy of material. The laser light source unit 152 may use, for example, a UV laser, a CO2 laser or a YAG laser.
The first light expanding portion 154 expands and uniformly distributes a laser light, and then converts it into a laser beam in the direction of a major axis.
The second light expanding portion 156 expands and uniformly distributes the laser light converted in the first light expanding portion 154, and then converts it into a laser beam in the direction of a major axis it should be noted that the first and second light expanding portions 154, 156 serve to illustrate exemplary optical accessories usable for the present embodiment of the invention. Other like accessories known to one skilled in the art that can perform the same or similar functions are within contemplation for use herein.
The cylinder lens 158 has an incident surface receiving light emitted from the second light expanding portion 156 and having a planar shape, and an emission surface having a convex shape. The cylinder lens 158 converts the emitted light into light parallel with an optical axis and emits one laser light toward the transparent substrate 122.
Referring to
Referring to
The laser light source unit 142 generates a laser beam by means of amplification and oscillation using emission phenomenon of inner energy of a material. The laser light source unit 142 may use; for example, a UV laser, a CO2 laser or a YAG laser.
The first light expanding portion 144 expands and uniformly distributes a laser light, and firstly converts it into a laser light in the direction of a major axis.
The second light expanding portion 146 expands and uniformly distributes the laser light converted in the first light expanding portion 144, and secondly converts it into a laser light in the direction of a major axis.
The first cylinder lens 148 has an incident surface receiving light output from the second light expanding portion 146 and having a planar shape, and an emission surface having a convex shape. The first cylinder lens 148 converts the emitted light into light parallel with an optical axis and emits it. The second cylinder lens 150 converts the emitted light into a light parallel with an optical axis and emits it toward the transparent substrate 122. At this time, the laser light being emitted through a plurality of the second cylinder lens 150 may be a point light, a slit beam or an anisotropic line beam, etc.
The wire grid polarizing plate 120 formed by the above apparatus and method transmits light parallel with its own transmission axis and reflects light perpendicular to the transmission axis. In other words, the wire grid polarizing plate 120 transmits a linearly polarized light, for example, light in X axis, having the same oscillating direction as that of the transmission hole 126 among light incident on the wire grid polarizing plate 120. Further, the wire grid polarizing plate 120 transmits a linearly polarized light, for example, light in Y axis, having the direction perpendicular to the transmission hole 126 among light incident on the wire grid polarizing plate 120.
The light converting portion 138 may be formed on the back surface of the wire grid polarizing plate 120 or on front or back surfaces of the diffusing sheet 136 or on the front surface of the reflecting sheet 134. The light converting portion 138 has a refraction index different from that of adjacent elements upward or downward and is formed of a material with a refraction index more than that of the air The light converting portion 138 refracts light reflected from the wire grid polarizing plate 120 and light reflected from the reflecting sheet 134. The refracted light is converted to transmit the wire gird polarizing plate 120.
Referring to
Meanwhile, a Y-directional polarized light that is not parallel with the transmission axis of the wire grid polarizing plate 120 among light generated from the light source unit 132 is reflected. The Y-directional polarized light reflected by the wire grid polarizing plate 120 is refracted by the light converting plate 138 and is incident on the reflecting sheet 134. The Y-directional polarized light incident on the reflecting sheet 134 is reflected again and is incident on the light converting plate 138. The Y-directional light incident on the light converting plate 138 is refracted again and converted into X,Y double directional polarized light that comprises both the X-directional polarized light (X) and the Y-directional polarized light (Y). The X-directional polarized light (X) that is parallel with the transmission axis of the wire grid polarizing plate 120 among the mixed light passes through the wire grid polarizing plate 120 and the Y-directional polarized light (Y) perpendicular to the transmission axis of the wire grid polarizing plate 120 is reflected. The Y-directional polarized light reflected repeats the above process. In this way, light is recycled between the wire grid polarizing plate 120 and the reflecting sheet 134, and thus brightness may be enhanced by more than 30% and the transmission rate of the polarization may be enhanced by more than 80% as well.
Referring to
The lower phase difference film 110 is formed of a RMM (Reactive Mesogen Mixture) material on the TFT substrate 106 so as to compensate phase difference resulting from a difference of the polarization of the liquid crystal layer based on a viewing angle by birefringence.
In other words, as shown in
Alternatively, as shown in
Alternatively, the lower phase difference film 110 may be disposed between the gate of the TFT 180 and an active layer (not shown) and functions as a gate insulating film 186 as well.
Referring to
An electroluminescence (EL) type backlight unit 172 supplies light to the LCD panel 100. The EL type backlight unit 172 comprises a light source substrate 162, a reflecting electrode 164 formed on the light source substrate 162 a transmission electrode 168 intersecting the reflecting electrode 164, and an organic thin film layer 166 interposed between the reflecting electrode 164 and the transmission electrode 168. Further, the EL type backlight unit 172 may comprise a separate protective layer 170 formed on the transmission electrode 168 so as to prevent damages of the EL type backlight unit 172.
The light source substrate 162 may be formed of a glass material or a plastic material with a flexible property.
The reflecting electrode 164 is formed on the light source substrate 162 and receives a driving signal for injecting electrons or holes. The reflecting electrode 164 uses a metal of a high reflectivity or an alloy of two or more metals so as to reflect light generated from the organic thin film layer 166,
The organic thin film layer 166 comprises a hole injection layer, a hole carry layer, a light emitting layer, an electron carry layer, and an electron injection layer sequentially deposited on the reflecting electrode 164.
The transmission electrode 168 is formed on the organic thin firm layer 166 and receives a driving signal for injecting holes or electrons. The transmission electrode 168 is formed of a transparent conductive material, for example, indium tin oxide (ITO) or indium zinc oxide (IZO), to transmit a visible ray generated from the organic thin film layer 166 to outside.
The EL type backlight unit 172 emits electrons and holes when the reflecting electrode 164 and the transmission electrode 168 receive a driving signal, and the holes and electrons emitted from the reflecting electrode 164 and the transmission electrode 168 are recombined in the organic thin film layer 166, thereby generating a visible ray.
The EL type backlight unit 172 is a flat light-emitting device, and as such the light is uniform within an emitting area without the need for a separate optical sheet such as a diffusion sheet, etc. Further, the light-emitting cells in the EL type backlight unit 172 may correspond to the pixels of the LCD panel (in other words, one light-emitting cell for every one pixel). Thus, the gray levels can be controlled like a pixel of the LCD panel.
The wire grid polarizing plate 120 transmits light parallel with its own transmission axis and reflects light perpendicular to the transmission axis. As shown in
Alternatively, as shown in
Alternatively, as shown in
Meanwhile, the wire grid polarizing plate 120 may be formed in the TFT substrate. For example, if the wire grid polarizing plate 120 is formed on the whole surface of the lower portion of the TFT substrate 106, the light converting portion is formed on the back surface of the TFT substrate 106.
According to at least one embodiment of the present invention, the liquid crystal display module can dispense with a separate brightness enhancement film since the liquid crystal display module selectively transmits and reflects light generated from the light source unit using the wire grid polarizing plate. Accordingly, the liquid crystal display module may enhance brightness and a polarizing transmission rate without a separate brightness enhancement film. Although the exemplary embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the present invention should not be limited to those precise embodiments and that various other changes and modifications may be affected therein by one of ordinary skill in the related art without departing from the spirit or scope of the invention. All such changes and modifications are intended to be included within the scope of the invention as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-0035181 | Apr 2006 | KR | national |
