Liquid crystal display (LCD) devices may be found in many electric devices. LCD devices include a screen with pixels that are configured to transmit or not transmit light according to an image input to form an image. Among other factors, the resolution of the image depends on the size of the pixels. Generally speaking, smaller pixels may be used to generate an image with a higher resolution than larger pixels. Accordingly, it is often desirable to produce LCD devices with as small of a pixel size as possible.
LCD devices typically include liquid crystal material contained between a pair of display panels. One of the display panels often includes the electronics to cause the liquid crystal material to transmit or not transmit light for each pixel, and the other display panel often includes a color filter to allow color to be produced by a pixel when it transmits light. The color filter may include optical layers such as a black matrix layer, one or more color filter layers, a planarization layer, and a dielectric layer. In producing a display panel with a color filter, it is generally desirable to generate the color filter as small as possible while maintaining the precision of the optical layers therein.
One form of the present invention provides a system for generating a color filter for a display panel. The system comprises a photoconductor drum, a first liquid toner cartridge configured to transfer first liquid toner to a first discharged portion of the photoconductor drum to form a first image on the photoconductor drum, a cylindrical intermediate transfer member configured to receive the image from the photoconductor drum, and an impression mechanism configured to drive a substrate along the intermediate transfer member to cause the first image to be transferred to the substrate.
In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.
As described herein, a system and method for creating layers on a front panel of a liquid crystal display (LCD) using a liquid electrophotography (LEP) process is provided. The layers may include one or more color filter layers, a black matrix layer, a planarization layer, and a dielectric layer, for example. Using the system and method, each layer is generated on a photoconductor drum and transferred to an intermediate transfer medium such as a blanket. The combined layers on the intermediate transfer medium are transferred to a substrate that comprises the front panel of a liquid crystal display (LCD).
Imaging system 102 is a laser imager configured to create a latent image on photoconductor drum 106. Charging system 104 includes a scorotron assembly (not shown) that includes one or more scorotron units (not shown). The scorotron units are configured to negatively charge photoconductor drum 106 as photoconductor drum 106 is rotated past charging system 104 as indicated by an arrow 118. Image system 102 includes at least one writing head configured to project a laser beam onto selected areas of photoconductor drum 106 to discharge the selected areas as photoconductor drum 106 is rotated past imaging system 102. The discharged areas of photoconductor drum 106 comprise the latent image.
Each of the liquid toner cartridges 108 includes a developer 109 and liquid toner of a selected type, e.g., black matrix, color filter, planarization, or dielectric, and color, e.g., red, green, blue, or black. The liquid toner comprises particles that have been milled into a pigmented plastic and dissolved into Isoparâ„¢, i.e., an Isoparaffinic solvent available from ExxonMobil Chemical Company, 13501 Katy Freeway, Houston, Tex. 77079 USA, along with a charge director. In one embodiment, one liquid toner cartridge 108 includes a black pigment that is used to create a black matrix layer. Three liquid toner cartridges 108 include red, green, and blue pigments, respectively, that are used to create color filter layers. One liquid toner cartridge 108 includes a transparent material that is used to create a planarization layer, and one liquid toner cartridge 108 includes a dielectric material that is used to create a dielectric layer. In other embodiments, system 100 includes other types or numbers of liquid toner cartridges 108.
In response to being activated, a liquid toner cartridge 108 develops the liquid toner using developer 109. As the discharged areas of photoconductor drum 106 pass over an activated liquid toner cartridge 108, liquid toner transfers from developer 109 in activated liquid toner cartridge 108 to the discharged areas of photoconductor drum 106 to create an image.
The image is transferred electrostatically from photoconductor drum 106 to blanket 112 as photoconductor drum 106 rotates past intermediate transfer member 110. Intermediate transfer member 110 rotates in the direction indicated by arrow 120. In one embodiment, blanket 112 comprises a multi-layer fabric-reinforced foam rubber configured to electrostatically transfer the liquid toner from photoconductor drum 106 to intermediate transfer member 110. In other embodiments, blanket 112 comprises another type of material. Intermediate transfer member 110 heats the image on blanket 112 to cause the Isopar in the image to evaporate. Blanket 112 also absorbs some of the Isopar in the image to increase the solid content of the image.
A discharge system (not shown) such as a light emitting diode (LED) erase lamp removes residual charge from photoconductor drum 106 prior to the image being transferred to blanket 112. After the image is transferred to blanket 112, a cleaning system (not shown) cleans photoconductor drum 106 to remove any remaining toner.
System 100 repeats the above process to create any number of additional layers of images on blanket 112. The additional layers may be the same type and/or color, i.e. use liquid toner from the same liquid toner cartridge 108, or may be a different type and/or color, i.e. use liquid toner from a different liquid toner cartridge 108 as any previous layers.
After all of the layers have been created on blanket 112, the combined image is transferred from blanket 112 to substrate 116 using impression mechanism 114. Impression mechanism 114 drives substrate 116 along intermediate transfer member 110 in the direction indicated by an arrow 122 and applies pressure to substrate 116 to cause the combined image, i.e. all layers created on blanket 112, to be transferred to substrate 116. The combination of substrate 116 and the layers transferred to substrate 116 are referred to herein as display panel 116. Substrate 116 comprises any material suitable for use as a display panel for a LCD device such as glass or clear plastic.
In other embodiments, photoconductor drum 106 includes a permanent pattern that comprises the latent image. In those embodiment, imaging system 102 may be omitted.
In
The developed image is transferred from photoconductor drum 106 to intermediate transfer member 110 as indicated in a block 206. To transfer the developed image from photoconductor drum 106 to intermediate transfer member 110, an electrical bias is applied to blanket 112 to cause the charged liquid toner that comprises the developed image to transfer to blanket 112 on intermediate transfer member 110.
The image is conditioned on intermediate transfer member 110 as indicated in a block 208. Intermediate transfer member 110 heats blanket 112 to cause the Isopar in the liquid toner to evaporate and the plastic-coated particles in the liquid toner to form a film to condition the image. By evaporating the Isopar, the liquid toner solidifies on blanket 112.
A determination is made as to whether there is another layer to generate as indicated in a block 210. If there is another layer to generate, then the process of blocks 202 through 208 is repeated for the next layer. The next layer may be generated using liquid toner from the same or a different liquid toner cartridge 108 as the previous layer.
If there is not another layer to generate, then the combined image, i.e. the images from each layer generated in the process of blocks 202 through 210, is transferred from intermediate transfer member 110 to substrate 116 as indicated in a block 212. Impression mechanism 114 drives substrate 116 between intermediate transfer member 110 and impression mechanism 114 and applies pressure between substrate 116 and intermediate transfer member 110 to cause the combined image to be transferred to substrate 116.
In one embodiment of the method of
In
An electrical bias is applies to intermediate transfer member 110 to transfer the image from photoconductor drum 106 to blanket 112 as indicated in a block 312. Intermediate transfer member 110 heats blanket 112 to condition the image by causing the Isopar in the liquid toner to evaporate and the plastic-coated particles in the liquid toner to form a film as indicated in a block 314.
A determination is made as to whether there is another layer to generate as indicated in a block 316. If there is another layer to generate, then photoconductor drum 106 is cleaned to remove any remaining toner as indicated in a block 318 and the process of blocks 302 through 314 is repeated for the next layer. The next layer may be generated using liquid toner from the same or a different liquid toner cartridge 108 as the previous layer.
If there is not another layer to generate, then impression mechanism 114 applies pressure between substrate 116 and intermediate transfer member 110 to cause the combined image to be transferred from blanket 112 to substrate 116 as impression mechanism 114 drives substrate 116 between intermediate transfer member 110 and impression mechanism 114 as indicated in a block 320.
In one embodiment of the method of
In
LCD device 702 comprises any type of LCD device such as a flat screen or rear projection television, a personal computer system display, a laptop or notebook computer system display, or a video or image display system, for example.
Although specific embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. Those with skill in the mechanical, electromechanical, electrical, and computer arts will readily appreciate that the present invention may be implemented in a very wide variety of embodiments. This application is intended to cover any adaptations or variations of the preferred embodiments discussed herein. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.