Filter and Method for Forming the Same

Abstract

A filter and a method for forming the same. The filter includes: a substrate; a matrix layer located on the substrate, the matrix layer having an opening therein; a color filter layer located within the opening, the color filter layer having a stacked structure, and the spectral half-widths of the color filter layers of different layers in the visible light range are different; due to the stacked structure of the color filter layer, for any layer of the color filter layer, in a spectrogram with the ordinate being the transmittance and the abscissa being the visible light wavelength, the spectral half-widths are different. Since each layer of the color filter layer filters light, in the total spectrogram of the color filter layer with the stacked structure, an effect of spectral half-width narrowing appears. The color purity of the filter is related to the width of the spectrum in the total spectrogram of the color filter layer. Narrowing of the spectrum helps to improve the color purity of the filter, thereby making the presentation effect of the color image more vivid.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid crystal display manufacturing, and particularly to a color filter and a method for forming the same. Background Art

[0002] As a digital display device, an LCD (Liquid Crystal Display) filters light sources through liquid crystals and color filters to generate images on a flat panel. It has the advantages of small occupied space, low power consumption, low radiation, no flicker, and reduced visual fatigue, and is widely used in various display devices.

[0003] The color filter is one of the key components of a liquid crystal display. In the material cost of a TFT-LCD panel, the color filter accounts for about 30%. The color filter generates the three primary colors of red, green, and blue by filtering light, and then mixes the three primary colors in different proportions to generate various colors, making the LCD present colors.

[0004] However, the existing color filters still need to be improved. Summary of the Invention

[0005] The problem solved by the present invention is to provide a color filter and a method for forming the same, which helps to improve color purity and make the presentation effect of color images more vivid.

[0006] To solve the above problems, the present invention provides a color filter, including: a substrate; a matrix layer located on the substrate, the matrix layer having openings therein; a color filter layer located in the openings, the color filter layer adopting a stacked structure, and the transmittance spectral half-widths of different layers of the color filter layer in the visible light range are different.

[0007] Optionally, the color filter layer adopts a two-layer structure or a three-layer structure.

[0008] Optionally, when the color filter layer adopts a two-layer structure, the color filter layer includes a first color filter layer and a second color filter layer, the first color filter layer is located in the opening, and the second color filter layer covers the first color filter layer.

[0009] Optionally, the transmittance spectral half-width of the second color filter layer in the visible light range is greater than that of the first color filter layer.

[0010] Optionally, the line width of the second color filter layer is greater than that of the first color filter layer.

[0011] Optionally, the thickness of the first color filter layer is 1.5um - 2.5um.

[0012] Optionally, the thickness of the second color filter layer is 1.5um - 2.5um.

[0013] Optionally, the color filter layer includes a plurality of color pixel units, and the color pixel units are composed of R sub-pixels, G sub-pixels, and B sub-pixels.

[0014] Optionally, it further includes a protective layer, which is located on the substrate and covers the matrix layer and the color filter layer.

[0015] Optionally, it further includes: a plurality of support columns, which are located on the protective layer and are arranged at intervals.

[0016] Correspondingly, the present invention further provides a method for forming a filter, including: providing a substrate; forming a matrix layer on the substrate, and forming an opening in the matrix layer; forming a color filter layer in the opening, the color filter layer adopts a laminated structure, and the spectral half-width of the transmittance spectrum of different layers of the color filter layer in the visible light range is different..

[0017] Optionally, the color filter layer adopts a two-layer structure or a three-layer structure.

[0018] Optionally, when the color filter layer adopts a two-layer structure, the color filter layer includes a first color filter layer and a second color filter layer, the first color filter layer is located in the opening, and the second color filter layer covers the first color filter layer.

[0019] Optionally, when the color filter layer adopts a two-layer structure, the color filter layer includes a first color filter layer and a second color filter layer, and the forming method of the color filter layer includes: forming the first color filter layer in the opening; forming the second color filter layer on the first color filter layer, and the second color filter layer covers the first color filter layer.

[0020] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0021] The filter includes: a substrate, a matrix layer is located on the substrate, there is an opening between adjacent matrix elements, a color filter layer is located in the opening, the color filter layer adopts a laminated structure, and the spectral half-width of the transmittance spectrum of different layers of the color filter layer in the visible light range is different. Since the color filter layer adopts a laminated structure, for any layer of the color filter layer, in the frequency spectrum diagram with the ordinate being the transmittance and the abscissa being the visible light wavelength, the spectral half-width is different. Because each layer of the color filter layer has a filtering effect on light, in the total frequency spectrum diagram of the laminated color filter layer, there is an effect of narrowing of the half-width. The color purity of the filter is related to the width of the spectrum in the total frequency spectrum diagram of the color filter layer. The spectrum narrows, which helps to improve the color purity of the filter, thereby making the presentation effect of the color image more vivid. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of a filter;

[0023] Figure 2 Schematic diagram of light emission from a display;

[0024] Figure 3 It is the transmittance spectrum of an existing filter;

[0025] Figures 4 to 6 It is a schematic structural diagram corresponding to each step in the method for forming a filter in an embodiment of the present invention;

[0026] Figure 7 It is the transmittance spectra of the first color filter layer and the second color filter layer in an embodiment of the present invention;

[0027] Figure 8 It is the transmittance spectrum of the filter in an embodiment of the present invention. Detailed implementation manners

[0028] Due to the inherent reasons of the material properties of the current filter, the transmittance spectrum of the photoresist material used in liquid crystal displays cannot achieve the color purity of OLED materials. For specific analysis, please refer to Figures 1 to 3 .

[0029] Please refer to Figure 1 , a structure of a filter, the filter includes: a substrate 100; a matrix layer 101 located on the substrate 100, and the matrix layer 101 has a plurality of openings 102 therein; a color filter layer 103 filling the openings 102; a protective layer 104 covering the matrix layer 101 and the color filter layer 103. Among them, the color filter layer 103 is a single-layer structure, and the color filter layer 103 contains an R pixel layer, a G pixel layer, and a B pixel layer; a support column 105 located on the protective layer 104.

[0030] The inventor found that, please refer to Figure 2 and Figure 3 , Figure 2 schematic diagram of light emission from a display, Figure 3 is the transmittance spectrum of the filter, 106 is liquid crystal, 107 is a light source, 105 is the human eye. The inventor found that due to the inherent reasons of the material properties, the transmittance spectrum of the photoresist material used in liquid crystal displays cannot achieve the color purity of OLED materials, thus restricting the use of the filter to a certain extent.

[0031] The inventors' research found that, since the color filter layer adopts a stacked structure, for any layer of the color filter layer, in the spectral diagram with the vertical coordinate being the transmittance and the horizontal coordinate being the visible light wavelength, the spectral half-widths are different. Because each layer of the color filter layer has a filtering effect on light, in the total spectral diagram of the stacked color filter layer, an effect of narrowing of the half-width appears. The color purity of the color filter is related to the width of the spectrum in the total spectral diagram of the color filter layer. The narrowing of the spectrum helps to improve the color purity of the color filter, thereby making the color image presentation effect more vivid.

[0032] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings.

[0033] Please refer to Figure 4 , a substrate 200 is provided.

[0034] In this embodiment, the substrate 200 includes a first surface and a second surface, and the first surface and the second surface are distributed oppositely.

[0035] In this embodiment, the substrate 200 is glass.

[0036] In other embodiments, the substrate 200 may also adopt a transparent material similar to glass materials.

[0037] Please refer to Figure 5 , a matrix layer 201 is formed on the substrate 200, and openings 202 are formed in the matrix layer 201.

[0038] In this embodiment, the formation process of the matrix layer (BM) 201 is as follows: a photoresist coating layer is formed on one surface (the first surface or the second surface) of the substrate 200. The photoresist coating layer generally uses a black photoresist material, aiming to define the boundaries of each pixel in the display area. Using a photomask with a preset pattern, ultraviolet light is irradiated onto the photoresist coating layer through the photomask to complete the exposure process. Then, the areas not irradiated by ultraviolet light are removed with an alkaline solution to form the matrix layer (BM) 201 with openings 202.

[0039] Please refer to Figure 6 , a color filter layer 203 is formed in the openings 202, and the color filter layer 203 adopts a stacked structure.

[0040] In this embodiment, the spectral half-widths of the transmittance spectra of different layers of the color filter layer are different within the visible light range.

[0041] In this embodiment, the stacked color filter layer 203 can improve color purity and enhance the quality of color image presentation. Since the color filter layer adopts a stacked structure, for any layer of the color filter layer, in the spectrogram with transmittance on the vertical coordinate and visible light wavelength on the horizontal coordinate, the spectral half-width is different. Because each layer of the color filter layer has a filtering effect on light, in the total spectrogram of the stacked color filter layer, an effect of narrowing of the half-width appears. The color purity of the filter is related to the width of the spectrum in the total spectrogram of the color filter layer. Narrowing of the spectrum helps to improve the color purity of the filter, thereby making the presentation effect of the color image more vivid.

[0042] In this embodiment, the color filter layer 203 adopts a two-layer stacked structure; in other embodiments, the color filter layer 203 can also adopt a stacked structure of three layers, four layers, etc. However, as the number of stacked layers of the color filter layer 203 increases, the transmittance decreases significantly, and at the same time, the difficulty of forming the color filter layer 203 increases, affecting the quality of the final imaging.

[0043] The color filter layer includes a plurality of color pixel units, and the color pixel units are arranged in a certain pattern by three primary color pixel layers of an R (red) pixel layer, a G (green) pixel layer, and a B (blue) pixel layer, and correspond one by one to the arrangement of TFTs (transistors).

[0044] In this embodiment, the color filter layer 203 includes a first color filter layer 204 and a second color filter layer 205.

[0045] In this embodiment, the photoresist material in the first color filter layer 204 is different from the photoresist material in the second color filter layer 205.

[0046] In other embodiments, the photoresist material in the first color filter layer 204 is the same as the photoresist material in the second color filter layer 205.

[0047] In this embodiment, the thickness of the first color filter layer 204 is 1.5um to 2.5um. When the thickness of the first color filter layer 204 is less than 1.5um, the thickness of the first color filter layer 204 is too thin, increasing the process difficulty and having a poor effect of spectral narrowing; when the thickness of the first color filter layer 204 is greater than 2.5um, the effect of spectral narrowing will be better, but the peak of the transmittance decreases too much, affecting the imaging quality. Additionally, the limitation of the current thickness manufacturing process is also a reason.

[0048] In this embodiment, the thickness of the second color filter layer 205 is 1.5um to 2.5um; when the thickness of the second color filter layer 205 is less than 1.5um, the thickness of the second color filter layer 205 is too thin, increasing the process difficulty and having a poor effect on spectral narrowing; when the thickness of the second color filter layer 205 is greater than 2.5um, the spectral narrowing effect will be better, but the peak of the transmittance decreases too much, affecting the imaging quality. Additionally, it is also due to the limitation of the current thickness manufacturing process.

[0049] Please refer to Figure 7 which respectively show the transmittance spectra of the first color filter layer 204 and the second color filter layer 205.

[0050] In this embodiment, the full-width at half-maximum of the transmittance spectrum of the second color filter layer 205 in the visible light range is greater than that of the first color filter layer 204.

[0051] In this embodiment, the line width of the second color filter layer 205 is greater than the line width of the first color filter layer 204.

[0052] In this embodiment, the difference range between the line width of the second color filter layer 205 and the line width of the first color filter layer 204 is 0.5 microns to 1 micron; when the difference between the line width of the second color filter layer 205 and the line width of the first color filter layer 204 is less than 0.5 microns, due to the too small difference between the line width of the second color filter layer 205 and the line width of the first color filter layer 204, it is restricted by the process conditions, resulting in the second color filter layer 205 being unable to completely cover the first color filter layer 204, causing color inconsistency at the edges and in the middle between the second color filter layer 205 and the first color filter layer 204 and resulting in display abnormalities; when the difference between the line width of the second color filter layer 205 and the line width of the first color filter layer 204 is greater than 1 micron, the formed second color filter layer 205 is too large, causing waste of the material of the second color filter layer 205 and increasing the cost.

[0053] In this embodiment, the first color filter layer 204 and the second color filter layer 205 have the same thickness.

[0054] In other embodiments, the thicknesses of the first color filter layer 204 and the second color filter layer 205 may also be different.

[0055] In this embodiment, the first color filter layer 204 fills the opening 202, and the first color filter layer 204 also covers part of the matrix layer 201.

[0056] In this embodiment, the second color filter layer 205 covers the first color filter layer 204.

[0057] In this embodiment, the three primary color pixel layers, namely the R (red) pixel layer, G (green) pixel layer, and B (blue) pixel layer, in the second color filter layer 205 correspond one-to-one with the three primary color pixel layers, namely the R (red) pixel layer, G (green) pixel layer, and B (blue) pixel layer, in the first color filter layer 204.

[0058] In this embodiment, the method for forming the color filter layer 203 includes: forming the second color filter layer 205 on the first color filter layer 204, and the second color filter layer 205 covers the first color filter layer 204.

[0059] Specifically, the formation process of the color filter layer 203 includes: forming an initial filter layer, such as an initial R (red) pixel layer, on the substrate 200 and the matrix layer 210. Using a mask with a preset pattern, ultraviolet light irradiates the initial filter layer, that is, the initial R (red) pixel layer, through the mask, and the R (red) pixel layer is formed on the corresponding substrate 200 and matrix layer 210. Then, the unexposed area by ultraviolet light is removed with an alkaline solution. After forming the R (red) pixel layer, the G pixel layer and the B pixel layer are formed in the openings at the required positions in the same way in sequence, so as to form three primary color pixel layers with a certain positional arrangement relationship. One three-primary-color pixel layer constitutes a color pixel unit, and multiple color pixel units constitute one layer of the color filter layer 203.

[0060] In this embodiment, after the three primary color pixel layers, namely the R (red) pixel layer, G (green) pixel layer, and B (blue) pixel layer, in the first color filter layer 204 are all formed, the second color filter layer 205 is formed.

[0061] In other embodiments, after forming the R (red) pixel layer in the first color filter layer 204, the R (red) pixel layer in the second color filter layer 205 is formed at the corresponding position; and so on to form the first color filter layer 204 and the second color filter layer 205.

[0062] In this embodiment, after forming the second color filter layer 203, a protective layer 206 is formed.

[0063] The protective layer (OC) 206 is located on the substrate 200 and covers the matrix layer 201 and the color filter layer 203.

[0064] In this embodiment, the purpose of the protective layer (OC) 206 is to protect the color filter layer 203 and the matrix layer 201.

[0065] In this embodiment, after forming the protective layer 206, a support pillar 207 is further formed.

[0066] In this embodiment, the forming step of the support pillar 207 includes: forming an initial support pillar layer on the protective layer 206, etching the initial support pillar layer, and forming the spaced-apart and discrete support pillars 207 on the protective layer 206.

[0067] The support pillars 207 are located on the protective layer 206 and are spaced apart.

[0068] In this embodiment, please refer to Figure 8 the transmittance spectrum of the filter. Since the color filter layer adopts a stacked structure, for any layer of the color filter layer, in the spectrogram with the ordinate being the transmittance and the abscissa being the visible light wavelength, the spectral half-width is different. Because each layer of the color filter layer has a filtering effect on light, in the total spectrogram of the stacked color filter layer, an effect of spectral half-width narrowing appears. The color purity of the filter is related to the width of the spectrum in the total spectrogram of the color filter layer. The narrowing of the spectrum helps to improve the color purity of the filter, thereby making the color image presentation effect more vivid.

[0069] Correspondingly, please refer to Figure 6 , the present invention also provides a filter, including a substrate 200; a matrix layer 201 located on the substrate 200, with openings 202 in the matrix layer 201; a color filter layer 203 located in the openings 202, and the color filter layer 203 adopts a stacked structure, and the spectral half-widths of different layers of the color filter layer are different in the visible light range.

[0070] In this embodiment, since the color filter layer 203 adopts a stacked structure, for any layer of the color filter layer, in the spectrogram with the ordinate being the transmittance and the abscissa being the visible light wavelength, the spectral half-width is different. Because each layer of the color filter layer has a filtering effect on light, in the total spectrogram of the stacked color filter layer 203, an effect of spectral half-width narrowing appears. The color purity of the filter is related to the width of the spectrum in the total spectrogram of the color filter layer. The narrowing of the spectrum helps to improve the color purity of the filter, thereby making the color image presentation effect more vivid.

[0071] In this embodiment, the color filter layer 203 adopts a two-layer structure, including a first color filter layer 204 and a second color filter layer 205.

[0072] In other embodiments, the color filter layer 203 may also adopt a three-layer structure or a four-layer structure, etc.

[0073] In this embodiment, the first color filter layer 204 is located within the opening 202, and the second color filter layer 205 covers the first color filter layer 204.

[0074] In this embodiment, the thickness of the first color filter layer 204 is 1.5um to 2.5um. When the thickness of the first color filter layer 204 is less than 1.5um, the thickness of the first color filter layer 204 is too thin, increasing the process difficulty and at the same time, the higher the light transmittance, the poorer the spectral narrowing effect, reducing the quality of the pattern imaging. When the thickness of the first color filter layer 204 is greater than 2.5um, although the thicker the first color filter layer 204, the lower the transmittance and the better the spectral narrowing effect. However, as the thickness of the first color filter layer 204 increases, when the thickness is too thick, the transmittance is too low, affecting the imaging quality. Additionally, it is also due to the limitation of the current thickness manufacturing process.

[0075] In this embodiment, the thickness of the second color filter layer 205 is 1.5um to 2.5um. When the thickness of the second color filter layer 205 is less than 1.5um, the thickness of the second color filter layer 205 is too thin, increasing the process difficulty and at the same time, the higher the light transmittance, the poorer the spectral narrowing effect, reducing the quality of the pattern imaging. When the thickness of the second color filter layer 205 is greater than 2.5um, although the thicker the second color filter layer 205, the lower the transmittance and the better the spectral narrowing effect. However, as the thickness of the second color filter layer 205 increases, when the thickness is too thick, the transmittance is too low, affecting the imaging quality. Additionally, it is also due to the limitation of the current thickness manufacturing process.

[0076] In this embodiment, the color filter layer includes a plurality of color pixel units, and the color pixel units are composed of R sub-pixels, G sub-pixels, and B sub-pixels.

[0077] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope defined by the claims.

Claims

1. A filter, characterized in that, Comprising: A substrate; A matrix layer located on the substrate, with openings formed therein; A color filter layer located within the openings. The color filter layer adopts a stacked structure, and the spectral half-width of the transmittance of different layers of the color filter layer within the visible light range is different. Among them, the color filter layer adopts a two-layer structure, and the color filter layer includes a first color filter layer and a second color filter layer. The first color filter layer is located within the openings, and the second color filter layer covers the first color filter layer.

2. The optical filter according to claim 1, wherein the spectral half-width of the transmittance of the second color filter layer within the visible light range is greater than that of the first color filter layer.

3. The optical filter according to claim 1, wherein the line width of the second color filter layer is greater than that of the first color filter layer.

4. The filter according to claim 1, wherein The thickness of the first color filter layer is 1.5 μm to 2.5 μm.

5. The optical filter according to claim 1, wherein The thickness of the second color filter layer is 1.5 μm to 2.5 μm.

6. The filter according to claim 1, characterized in that, The color filter layer includes a plurality of color pixel units, and the color pixel units are composed of R sub-pixels, G sub-pixels, and B sub-pixels.

7. The filter according to claim 1, characterized in that It further includes a protective layer located on the substrate and covering the matrix layer and the color filter layer.

8. The filter according to claim 7, characterized in that, It further comprises: A plurality of support columns located on the protective layer and arranged at intervals.

9. A method for forming a filter, characterized in that, Comprising: Providing a substrate; Forming a matrix layer on the substrate and forming openings within the matrix layer; Forming a color filter layer within the openings. The color filter layer adopts a stacked structure, and the spectral half-width of the transmittance of different layers of the color filter layer within the visible light range is different. Among them, the color filter layer adopts a two-layer structure, and the color filter layer includes a first color filter layer and a second color filter layer. The first color filter layer is located within the openings, and the second color filter layer covers the first color filter layer.

10. The method for forming a filter according to claim 9, wherein, The color filter layer adopts a two-layer structure, and the color filter layer includes a first color filter layer and a second color filter layer. The forming method of the color filter layer includes: Forming the first color filter layer within the openings; Forming the second color filter layer on the first color filter layer, and the second color filter layer covers the first color filter layer.

Images