Method of making a liquid crystal display with color filters

• US 4,673,253 A
• Filed: 04/04/1986
• Issued: 06/16/1987
• Est. Priority Date: 10/07/1983
• Status: Expired due to Term

• Current Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Original Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Inventors: Yamamoto, Etsuo, Tanabe, Hiroshi, Aota, Katsumi, Togashi, Seigo, Sekiguchi, Kanetaka, Sorimachi, Kazuaki
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Lewis, David
• Application Number:
  US06/848,894
• Time in Patent Office: 438 Days
• Field of Search: 350/339 F, 350/320, 428/1, 428/108, 430/313, 430/20
• US Class Current: 349/106
• CPC Class Codes: G02F 1/133516 Methods for their manufacture, e.g. printing, electro-deposition or photolithography
• CPC Class Codes: G03F 7/0007 Filters, e.g. additive colour filters; Components for display devices
• CPC Class Codes: Y10S 359/90 Methods

Abstract

A liquid crystal display device having a color filter comprises a liquid crystal shutter device, at least one color filter layer formed on one surface of the liquid crystal shutter device, and at least one diffusion preventing layer for protecting the color filter layer. The color filter layer is prepared by a photolithographic process comprising the steps of forming a layer being colored of gelatin and the like on one surface of the liquid crystal shutter device, coating a photoresist layer thereon, while illuminating the liquid crystal shutter device by white light from the other surface thereof, applying a voltage to the selected opposed surface thereof, applying a voltage to the selected opposed electrode groups to form a latent image in alignment with the electrode groups by a photochemical action, developing the latent image to form a photomask, and while using this mask as a guide, coloring the layer being colored.

Claims

1. A process for making a liquid crystal display device having a color filter by a photolithographic method, the process comprising the steps of:

providing a liquid crystal shutter device having;

a pair of opposed glass plates;

opposed electrode groups on the respective inner surfaces of the glass plates;

at least one polarizer;

a liquid crystal layer between the opposed electrode groups; and

a voltage applying means for selectively applying

a voltage applying means for selectively applying a voltage across the electrode groups;

forming a layer being colored on one surface of the liquid crystal shutter device;

forming a photoresist layer thereon;

while illuminating the liquid crystal shutter device from the other surface thereof by white light, applying the voltage across the selected opposed electrode groups through the voltage applying means to form a latent image on the photoresist layer by a photochemical action, the latent image being aligned with the electrode groups;

developing the latent image to form a photomask;

after a while, while using the photomask as a guide, coloring the layer being colored to form a color filter layer; and

forming a diffusion preventing layer on the color filter layer for protecting the color filter layer.

2. A process for making a liquid crystal display device having a color filter by a photolithographic method, the process comprising the steps of:

providing a liquid crystal shutter device having;

a pair of opposed glass plates;

opposed electrode groups on the respective inner surfaces of the glass plates;

at least one polarizer;

a liquid crystal layer between the opposed electrode groups; and

a voltage applying means for selectively applying a voltage across the electrode groups;

forming a first layer being colored on one surface of the liquid crystal shutter device;

forming a first photoresist layer of a negative type thereon;

while illuminating the liquid crystal shutter device from the other surface thereof by white light, applying the voltage across the first selected opposed electrode groups through the voltage applying means to prevent the light from passing through a portion of the liquid crystal layer to which the voltage is applied and to expose a portion of the photoresist layer sensitive to light, thereby forming a first pattern latent image, the first latent image being hardened;

developing the first latent image to form a first pattern mask;

while using the mask as a guide, etching away the portion of the first layer being colored corresponding to the first selected opposed electrode groups;

removing the mask;

coating and dying the unetched portion of the first layer being colored with a first color of three primary colors to form a first colored layer;

forming a first diffusion preventing layer on an upper surface of the first colored layer;

forming a second layer being colored and a second photoresist layer of the negative type on an upper surface of the first preventing layer;

while illuminating the liquid crystal shutter device from the other surface thereof by white light, applying the voltage across the second selected opposed electrode groups through the voltage applying means to prevent the light from passing through a portion of the liquid crystal layer to which the voltage is applied and to expose a portion of the second photoresist layer sensitive to the light, thereby forming a second pattern latent image, the second pattern latent image being hardened;

developing the second latent image to form a second pattern mask,

while using the mask as a guide, etching away the portion of the second layer being colored corresponding to the second selected opposed electrode groups;

removing the second pattern mask;

coating and dyeing the unetched portion of the second layer being colored with a second color of the three primary colors to form a second colored layer;

forming a second diffusion preventing layer on an upper surface of the second colored layer;

forming a third layer being colored and a third photoresist layer of the negative type on an upper surface of the second preventing layer;

while illuminating the liquid crystal shutter device from the other surface thereof by white light, applying the voltage across the third selected opposed electrode groups through the voltage applying means to prevent the light from passing through a portion of the liquid crystal layer to which the voltage is applied and to expose a portion of the third photoresist layer sensitive to the light, thereby forming a third pattern latent image, the third pattern latent image being hardened;

developing the second latent image to form a second pattern mask;

while using the mask as a guide, etching away the portion of the third layer being colored corresponding to the third selected opposed electrode groups;

removing the third pattern mask;

coating and dyeing the unetched portion of the third layer being colored with a third color of the three primary colors to form a third colored layer; and

forming a third diffusion preventing layer on an upper surface of the third colored layer.

3. A process for making a liquid crystal display device having a color filter by a photolithographic method, the process comprising the steps of:

providing a liquid crystal shutter device having;

a pair of opposed glass plates;

opposed electrode groups on the respective inner surfaces of the glass plates;

at least one polarizer;

a liquid crystal layer between the opposed electrode groups; and

a voltage applying means for selectively applying a voltage across the electrode groups;

forming a layer being colored on one surface of the liquid crystal shutter device;

forming a first photoresist layer of a positive type thereon;

while illuminating the liquid crystal shutter device from the other surface thereof by white light, applying the voltage across the first selected opposed electrode groups through the voltage applying means to prevent the light from passing through a portion of the liquid crystal to which the voltage is applied and to expose a portion of the first photoresist layer sensitive to the light, thereby forming a first latent image which is soluble;

developing the latent image to leave the unexposed portion of the first photoresist layer, thereby forming a mask for a first coloring guide;

pouring a dye of a first color of three primary colors into the first layer being colored from a hole therein caused by the solution of the mask to form a first colored portion;

removing the mask for a first coloring guide to reveal the layer being colored having the first colored portion;

forming a second photoresist layer of the positive type on an upper surface of the layer being colored;

while illuminating the liquid crystal shutter device from the other surface thereof by white light, applying the voltage across the second selected opposed electrode groups through the voltage applying means to prevent the light from passing through a portion of the light crystal to which the voltage is applied and to expose a portion of the second photoresist layer sensitive to light, thereby forming a second latent image which is soluble;

developing the latent image to leave the unexposed portion of the second photoresist layer, thereby forming a mask for a second coloring guide;

pouring a dye of a second color of the three primary colors into the second layer being colored from a hole therein caused by the solution of the mask to form a second colored portion;

removing the mask for a second coloring guide to reveal the layer being colored having the first and second colored portions;

forming a third photoresist layer of the positive type of the upper surface of the layer being colored;

while illuminating the liquid crystal shutter device from the other surface thereof by white light, applying the voltage across the third selected opposed electrode groups through the voltage applying means to prevent the light from passing through a portion of the liquid crystal to which the voltage is applied and to expose a portion of the third photoresist layer sensitive to the light, thereby forming a third latent image which is soluble;

developing the latent image to leave the unexposed portion of the third photoresist layer, thereby forming a mask for a third coloring guide;

pouring a dye of a third color of the three primary colors into the third layer being colored from a hole therein caused by the solution of the mask to form a third colored portion;

removing the mask for a third coloring guide to reveal the layer having the first, second and third colored portions, part of the first, second and third portions being overlapping; and

forming a diffusion preventing layer on the upper surface of the layer having the first, second and third colored portions.