JP2014041295A - Method for manufacturing liquid crystal display device - Google Patents

Abstract

A method for manufacturing a liquid crystal display device capable of suppressing a decrease in manufacturing yield is provided.
A first color filter having a transmittance peak in a first wavelength range on an insulating substrate, and a second color filter having a transmittance peak in a second wavelength range different from the first wavelength range. Forming an alignment mark on the first color filter, irradiating the alignment mark with reference light, and detecting the alignment mark, wherein the alignment mark and the alignment mark A method for manufacturing a liquid crystal display device, wherein a first contrast of the first color filter with respect to the reference light is higher than a second contrast of the alignment mark and the second color filter with respect to the reference light.
[Selection] Figure 7

Description

  Embodiments described herein relate generally to a method for manufacturing a liquid crystal display device.

  2. Description of the Related Art In recent years, flat display devices have been actively developed. In particular, liquid crystal display devices have attracted particular attention because of their advantages such as light weight, thinness, and low power consumption. In particular, an active matrix liquid crystal display device in which a thin film transistor (TFT) is incorporated as a switching element in each pixel has a configuration in which a transmissive liquid crystal display panel and a backlight are combined.

  Recently, with the increase in brightness of the backlight, power consumption has increased, and a decrease in battery duration has become a problem in portable displays and the like. Therefore, in order to effectively use the light from the backlight, an interference color filter using optical interference is provided on the array substrate side, so that the light that has been absorbed by the conventional color filter and lost can be used effectively. Proposed. This interference color filter has, for example, three types of color filters that transmit three primary colors (for example, red (R), green (G), and blue (B)) necessary to realize full color display. That is, when white light is irradiated to the interference color filter, wavelength selectivity for light transmission and reflection occurs in each of the three types of color filters. Such an interference color filter may extend not only to an active area for displaying an image but also to a peripheral area of the array substrate in order to reduce a photolithography process and improve a manufacturing yield. .

  In the process of manufacturing a liquid crystal display device, it is important to optically detect the presence or absence of each substrate or align each substrate based on the alignment mark. However, when the alignment mark overlaps the interference color filter, in the manufacturing apparatus for manufacturing the liquid crystal display device, it becomes difficult to detect the alignment mark, and the presence or absence of the array substrate cannot be detected optically, There is a problem that the array substrate cannot be aligned. Such inconvenience contributes to a decrease in manufacturing yield.

Japanese National Patent Publication No. 8-508114

  An object of the present embodiment is to provide a method of manufacturing a liquid crystal display device capable of suppressing a decrease in manufacturing yield.

According to this embodiment,
Forming a first color filter having a transmittance peak in a first wavelength range and a second color filter having a transmittance peak in a second wavelength range different from the first wavelength range on an insulating substrate; A method for manufacturing a liquid crystal display device, comprising: forming an alignment mark on the first color filter; and irradiating the alignment mark with reference light to detect the alignment mark, wherein the alignment mark and the first color filter The first contrast with respect to the reference light is higher than the second contrast with respect to the reference light between the alignment mark and the second color filter.

FIG. 1 is a diagram schematically showing a configuration of a liquid crystal display device according to the present embodiment. FIG. 2 is a diagram schematically showing a configuration and an equivalent circuit of the liquid crystal display panel shown in FIG. FIG. 3 is a diagram schematically showing a cross-sectional structure of the liquid crystal display panel shown in FIG. FIG. 4 is a diagram illustrating an example of a reflection spectrum and a transmission spectrum of the color filter layer illustrated in FIG. 3. FIG. 5 is a cross-sectional view for explaining a process of forming a color filter layer on an insulating substrate. FIG. 6 is a cross-sectional view for explaining a process of forming alignment marks on the color filter layer. FIG. 7 is a plan view of the first mother substrate shown in FIG. FIG. 8 is a plan view for explaining a process of drawing a sealing material on the first mother substrate shown in FIG. FIG. 9 is a plan view for explaining a step of dropping a liquid crystal material on the first mother substrate shown in FIG. FIG. 10 is a plan view for explaining a process of bonding the first mother substrate and the second mother substrate shown in FIG. FIG. 11 is a plan view for explaining a step of taking out the liquid crystal display panel from the mother substrate pair shown in FIG. FIG. 12 is a plan view showing an example of the first alignment mark arranged on the first mother substrate. FIG. 13 is a cross-sectional view for explaining a step of detecting the first alignment mark. FIG. 14 is a cross-sectional view for explaining another process of detecting the first alignment mark. FIG. 15 is a plan view of another first mother substrate applicable to this embodiment.

  Hereinafter, the present embodiment will be described in detail with reference to the drawings. In each figure, the same reference numerals are given to components that exhibit the same or similar functions, and duplicate descriptions are omitted.

  FIG. 1 is a diagram schematically showing a configuration of a liquid crystal display device according to the present embodiment.

  That is, the liquid crystal display device 1 includes an active matrix type transmissive liquid crystal display panel LPN, a driving IC chip 2 and a flexible wiring board 3 connected to the liquid crystal display panel LPN, a backlight 4 that illuminates the liquid crystal display panel LPN, and the like. I have.

  The liquid crystal display panel LPN includes an array substrate AR, a counter substrate CT arranged to face the array substrate AR, and a liquid crystal layer (not shown) held between the array substrate AR and the counter substrate CT. . Such a liquid crystal display panel LPN includes an active area ACT for displaying an image, a peripheral area PRP outside the active area ACT, and the like. This active area ACT is composed of a plurality of pixels PX arranged in an m × n matrix (where m and n are positive integers). The peripheral area PRP includes a mounting portion MT on which signal supply sources such as the driving IC chip 2 and the flexible wiring board 3 are mounted. The mounting portion MT is formed on the array substrate AR that extends outward from the substrate end portion CTE of the counter substrate CT.

  The backlight 4 is disposed on the back side of the array substrate AR. As such a backlight 4, a light source provided with a light emitting diode (LED) or a cold cathode tube (CCFL) as a light source is applied, but a detailed description of the structure is omitted.

  FIG. 2 is a diagram schematically showing a configuration and an equivalent circuit of the liquid crystal display panel LPN shown in FIG.

  The array substrate AR includes a plurality of gate lines G (G1 to Gn), a plurality of auxiliary capacitance lines C (C1 to Cn), a plurality of source lines S (S1 to Sm), and the like in the active area ACT. Each gate line G is drawn outside the active area ACT and connected to the gate driver GD. Each source line S is drawn outside the active area ACT and connected to the source driver SD. Each auxiliary capacitance line C is drawn outside the active area ACT and is electrically connected to a voltage application unit VCS to which an auxiliary capacitance voltage is supplied.

  Each pixel PX includes a switching element SW and a pixel electrode PE disposed on the array substrate AR, a counter electrode CE, and the like. The switching element SW is electrically connected to the gate line G and the source line S. The pixel electrode PE is electrically connected to the switching element SW. The counter electrode CE is formed in common to the plurality of pixel electrodes PE via the liquid crystal layer LQ. The counter electrode CE is electrically connected to, for example, a power supply unit VS to which a common potential is supplied.

  In the present embodiment, the counter electrode CE may be disposed on the array substrate AR or may be disposed on the counter substrate CT. In the liquid crystal display panel LPN having the configuration in which the counter electrode CE is disposed on the array substrate AR together with the pixel electrode PE, the liquid crystal layer LQ is mainly used by utilizing a horizontal electric field formed between the pixel electrode PE and the counter electrode CE. The liquid crystal molecules that make up the are switched. Further, in the liquid crystal display panel LPN having a configuration in which the counter electrode CE is disposed on the counter substrate CT, a liquid crystal layer mainly utilizing a vertical electric field or an oblique electric field formed between the pixel electrode PE and the counter electrode CE. The liquid crystal molecules constituting the LQ are switched.

  FIG. 3 schematically shows a cross-sectional structure of the liquid crystal display panel LPN shown in FIG. Here, a cross-sectional structure of the first pixel PX1 that displays green, the second pixel PX2 that displays blue, and the third pixel PX3 that displays red is shown.

  That is, the first pixel PX1 includes a first color filter CF1, a first switching element SW1, a first pixel electrode PE1, and the like. The second pixel PX2 includes a second color filter CF2, a second switching element SW2, a second pixel electrode PE2, and the like. The third pixel PX3 includes a third color filter CF3, a third switching element SW3, a third pixel electrode PE3, and the like.

  The array substrate AR is formed using a first insulating substrate 10 having optical transparency such as a glass substrate or a resin substrate. The color filter layer 30 including the first color filter CF1, the second color filter CF2, and the third color filter CF3 is disposed on the first insulating substrate 10. The first to third color filters are interference color filters, respectively.

  Although details will be described later, the first color filter CF1 mainly transmits light in a first wavelength range including a green wavelength (for example, a wavelength range of 500 nm to 580 nm), and has a transmittance peak in the first wavelength range. It is what you have. The second color filter CF2 mainly transmits light in a second wavelength range (for example, a wavelength range of 400 nm to 500 nm) including a blue wavelength different from the first wavelength range, and a transmittance peak in the second wavelength range. It is what has. The third color filter CF3 mainly transmits light in a third wavelength range (for example, a wavelength range of 580 nm to 700 nm) including a red wavelength different from the first wavelength range and the second wavelength range, and this third wavelength. It has a transmittance peak in the range.

  The first color filter CF1, the second color filter CF2, and the third color filter CF3 mainly reflect wavelengths outside the transmitted wavelength range. The first color filter CF1 has a higher reflectance in the second wavelength range and the third wavelength range than in the first wavelength range. The second color filter CF2 has a higher reflectance in the first wavelength range and the third wavelength range than in the second wavelength range. The third color filter CF1 has a higher reflectance in the first wavelength range and the second wavelength range than in the third wavelength range.

  In this embodiment, the color filter layer 30 employs a Fabry-Perot interference color filter utilizing the principle of optical interference, and is configured by laminating a plurality of thin films of inorganic materials having different refractive indexes. Yes. That is, the color filter layer 30 includes a first semi-transmissive layer 31 disposed on the inner surface 10A of the first insulating substrate 10, a transmissive layer (or spacer layer) 33 positioned on the first semi-transmissive layer 31, and a transmissive layer. A second semi-transmissive layer 32 is provided on the layer 33.

  The first semi-transmissive layer 31 and the second semi-transmissive layer 32 are provided in common to the first color filter CF1, the second color filter CF2, and the third color filter CF3, respectively. In the first color filter CF1, the second color filter CF2, and the third color filter CF3, the film thickness of the first semi-transmissive layer 31 is substantially constant, and the film thickness of the second semi-transmissive layer 32. Is also substantially constant.

  The first semi-transmissive layer 31 and the second semi-transmissive layer 32 have a configuration in which a plurality of dielectric films having different refractive indexes are stacked. As an example, the first semi-transmissive layer 31 and the second semi-transmissive layer 32 are each configured by a dielectric multilayer film in which silicon nitride (SiN) layers and silicon oxide (SiO) layers are alternately stacked. . The number of laminated dielectric multilayer films is two or more. However, as the number of layers increases, the number of manufacturing steps increases and the manufacturing cost increases.

  The transmissive layer 33 is provided in common for the first color filter CF1, the second color filter CF2, and the third color filter CF3. However, in the first color filter CF1, the second color filter CF2, and the third color filter CF3, the film thickness of the transmission layer 33 is different. In the illustrated example, the thickness of the transmission layer 33 in the second color filter CF2 is smaller than the thickness of the transmission layer 33 in the first color filter CF1, and the thickness of the transmission layer 33 in the third color filter CF3 is the first. It is thinner than the thickness of the transmission layer 33 in the two-color filter CF2. Such a transmission layer 33 is constituted by, for example, a silicon nitride layer or a silicon oxide layer.

  Hereinafter, a more specific configuration example of the color filter layer 30 will be described. In the illustrated example, the color filter layer 30 has a configuration in which each of the first semi-transmissive layer 31 and the second semi-transmissive layer 32 is formed by stacking four thin films. Note that the number of thin films constituting the color filter layer 30 is not limited to the illustrated example.

  The first semi-transmissive layer 31 includes a first silicon nitride layer 311 disposed on the inner surface 10A of the first insulating substrate 10, a first silicon oxide layer 312 stacked on the first silicon nitride layer 311, A second silicon nitride layer 313 stacked on the first silicon oxide layer 312 and a second silicon oxide layer 314 stacked on the second silicon nitride layer 313 are configured. The first silicon nitride layer 311, the first silicon oxide layer 312, the second silicon nitride layer 313, and the second silicon oxide layer 314 all have a first color filter CF1 and a second color filter CF2. And continuously formed over the third color filter CF3 without interruption.

  The transmission layer 33 includes a third silicon nitride layer 331, a fourth silicon nitride layer 332, and a fifth silicon nitride layer 333. The third silicon nitride layer 331 is formed in an island shape corresponding to the first color filter CF1, and is stacked on the second silicon oxide layer 314. The fourth silicon nitride layer 332 is formed in an island shape corresponding to the first color filter CF1 and the second color filter CF2. That is, the fourth silicon nitride layer 332 covers the third silicon nitride layer 331 corresponding to the first color filter CF1, and is stacked on the second silicon oxide layer 314 corresponding to the second color filter CF2. Has been. The fifth silicon nitride layer 333 is continuously formed without interruption over the first color filter CF1, the second color filter CF2, and the third color filter CF3. That is, the fifth silicon nitride layer 333 covers the fourth silicon nitride layer 332 corresponding to the first color filter CF1 and the second color filter CF2, and the second silicon oxide layer 333 corresponding to the third color filter CF3. It is laminated on the physical layer 314.

  The second semi-transmissive layer 32 includes a third silicon oxide layer 321 stacked on the fifth silicon nitride layer 333, a sixth silicon nitride layer 322 stacked on the third silicon oxide layer 321, and The fourth silicon oxide layer 323 is stacked on the sixth silicon nitride layer 322, and the seventh silicon nitride layer 324 is stacked on the fourth silicon oxide layer 323. The third silicon oxide layer 321, the sixth silicon nitride layer 322, the fourth silicon oxide layer 323, and the seventh silicon nitride layer 324 all have a first color filter CF1 and a second color filter CF2. And continuously formed over the third color filter CF3 without interruption.

  A first silicon nitride layer 311, a second silicon nitride layer 313, a third silicon nitride layer 331, a fourth silicon nitride layer 332, a fifth silicon nitride layer 333, a sixth silicon nitride layer 322, and The seventh silicon nitride layer 324 functions as a high refractive index layer (the refractive index in the visible light wavelength range is about 2.0 to 2.7). The first silicon oxide layer 312, the second silicon oxide layer 314, the third silicon oxide layer 321, and the fourth silicon oxide layer 323 have a low refractive index that is lower than that of the high refractive index layer. It functions as an index layer (the refractive index in the visible light wavelength range is about 1.5).

  The first silicon nitride layer 311, the second silicon nitride layer 313, the sixth silicon nitride layer 322, and the seventh silicon nitride layer 324 include the first color filter CF1, the second color filter CF2, and the first color filter CF2. Each of the three color filters CF3 has the same film thickness, for example, a film thickness of 58 nm. The first silicon oxide layer 312, the second silicon oxide layer 314, the third silicon oxide layer 321, and the fourth silicon oxide layer 323 include the first color filter CF1, the second color filter CF2, and the first color filter CF2. Each of the three color filters CF3 has the same film thickness, for example, a film thickness of 92 nm. That is, the low refractive index layer constituting the first semi-transmissive layer 31 and the second semi-transmissive layer 32 is thicker than the high refractive index layer.

  The third silicon nitride layer 331 has a thickness of 37 nm, for example. The fourth silicon nitride layer 332 has a thickness of 48 nm, for example. The fifth silicon nitride layer 333 has a thickness of 30 nm, for example. In other words, in the first color filter CF1, the transmission layer 33 constituted by the stacked body of the third silicon nitride layer 331, the fourth silicon nitride layer 332, and the fifth silicon nitride layer 333 has a thickness of 115 nm. have. Further, in the second color filter CF2, the transmission layer 33 constituted by the stacked body of the fourth silicon nitride layer 332 and the fifth silicon nitride layer 333 is thinner than the first color filter CF1 and has a thickness of 78 nm. Have. In the third color filter CF3, the transmission layer 33 constituted by the fifth silicon nitride layer 333 is thinner than the second color filter CF2 and has a thickness of 30 nm.

  The color filter layer 30 having such a configuration is covered with the first insulating film 11. That is, the first insulating film 11 is disposed on the seventh silicon nitride layer 324. Such a first insulating film 11 is a silicon oxide (SiO) layer.

  The first to third switching elements SW1 to SW3 are formed on the first insulating film 11. In the illustrated example, the first switching element SW1 is located above the first color filter CF1, the second switching element SW2 is located above the second color filter CF2, and the third switching element SW3 is the third color filter CF3. Is located above. Each of the first to third switching elements SW1 to SW3 is a top gate type thin film transistor provided with a polysilicon semiconductor layer and has the same structure, but here, paying attention to the first switching element SW1. The structure will be described more specifically, and the description of the structure of the second switching element SW2 and the third switching element SW3 will be omitted.

  The first switching element SW1 includes a polysilicon semiconductor layer SC located on the first insulating film 11. The polysilicon semiconductor layer SC is covered with the second insulating film 12. The second insulating film 12 is also disposed on the first insulating film 11. On the second insulating film 12, the gate electrode WG of the first switching element SW1 is disposed. The gate electrode WG is covered with the third insulating film 13. The third insulating film 13 is also disposed on the second insulating film 12. The second insulating film 12 and the third insulating film 13 are made of an inorganic material such as silicon oxide (SiO) or silicon nitride (SiN).

  On the third insulating film 13, the source electrode WS and the drain electrode WD of the first switching element SW1 are disposed. The source electrode WS and the drain electrode WD are in contact with the polysilicon semiconductor layer SC, respectively. These source electrode WS and drain electrode WD are covered with a fourth insulating film 14. The fourth insulating film 14 is also disposed on the third insulating film 13. The fourth insulating film 14 is formed of an inorganic material such as silicon oxide (SiO) or silicon nitride (SiN) or a resin material.

  The first pixel electrode PE1 is formed on the fourth insulating film 14 and is located above the first color filter CF1. The first pixel electrode PE1 is electrically connected to the drain electrode WD of the first switching element SW1 through a contact hole that penetrates the fourth insulating film 14. Similarly, the second pixel electrode PE2 is formed on the fourth insulating film 14 and is located above the second color filter CF2. The second pixel electrode PE2 is electrically connected to the drain electrode WD of the second switching element SW2. Similarly, the third pixel electrode PE3 is formed on the fourth insulating film 14 and is located above the third color filter CF3. The third pixel electrode PE3 is electrically connected to the drain electrode WD of the third switching element SW3.

  The first pixel electrode PE1, the second pixel electrode PE2, and the third pixel electrode PE3 are made of a light-transmitting conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). ) Etc. The first pixel electrode PE1, the second pixel electrode PE2, and the third pixel electrode PE3 are covered with the first alignment film AL1.

  The counter substrate CT is formed using a second insulating substrate 20 having optical transparency such as a glass substrate or a resin substrate. The counter substrate CT includes a black matrix BM on the inner surface 20A of the second insulating substrate 20 facing the array substrate AR. The black matrix BM is disposed so as to face the first switching element SW1, the second switching element SW2, the third switching element SW3, and wiring portions such as a source wiring, a gate wiring, and an auxiliary capacitance line.

  In the illustrated example, the counter substrate CT includes the first colored layer CF11, the second colored layer CF12, and the third colored layer CF13 on the inner surface 20A of the second insulating substrate 20, but may be omitted. . The first colored layer CF11 is formed of a colored resin (for example, a green resin) that transmits light in the first wavelength range. The second colored layer CF12 is formed of a colored resin (for example, a blue resin) that transmits light in the second wavelength range. The third colored layer CF13 is formed of a colored resin (for example, a red resin) that transmits light in the third wavelength range.

  In the illustrated example, the counter substrate CT includes a counter electrode CE on the surface of the first colored layer CF11, the second colored layer CF12, and the third colored layer CF13 that faces the array substrate AR. As described above, the counter electrode CE may be provided on the array substrate AR. Further, an overcoat layer made of a transparent resin material may be interposed between the first colored layer CF11, the second colored layer CF12, the third colored layer CF13, and the counter electrode CE. The counter electrode CE is formed of a light-transmitting conductive material such as ITO or IZO, for example. The surface of the counter substrate CT facing the array substrate AR is covered with the second alignment film AL2.

  The array substrate AR and the counter substrate CT as described above are arranged so that the first alignment film AL1 and the second alignment film AL2 face each other. At this time, between the array substrate AR and the counter substrate CT, for example, a columnar spacer integrally formed on one substrate with a resin material is disposed, and a predetermined cell gap, for example, a cell gap of 2 to 7 μm is formed. It is formed.

  The liquid crystal layer LQ is held in a cell gap formed between the array substrate AR and the counter substrate CT, and is disposed between the first alignment film AL1 and the second alignment film AL2.

  A first optical element OD1 including a first polarizing plate PL1 and the like is disposed on the outer surface 10B of the first insulating substrate 10 constituting the array substrate AR. The first optical element OD1 is located on the side facing the backlight 4 of the liquid crystal display panel LPN, and controls the polarization state of incident light incident on the liquid crystal display panel LPN from the backlight 4.

  A second optical element OD2 including a second polarizing plate PL2 is disposed on the outer surface 20B of the second insulating substrate 20 constituting the counter substrate CT. The second optical element OD2 is located on the display surface side of the liquid crystal display panel LPN, and controls the polarization state of the outgoing light emitted from the liquid crystal display panel LPN.

  According to such a configuration, of the backlight light emitted from the backlight 4, the transmitted light from the liquid crystal display panel LPN in the optical path passing through the first pixel electrode PE1 via the first color filter CF1 is green (G). The transmitted light from the liquid crystal display panel LPN in the optical path passing through the second pixel electrode PE2 via the second color filter CF2 exhibits blue (B), and the optical path passing through the third pixel electrode PE3 via the third color filter CF3 The transmitted light from the liquid crystal display panel LPN is red (R).

  The light that has not passed through the first color filter CF1, the second color filter CF2, and the third color filter CF3 is almost entirely reflected, returned to the backlight 4 side, and reused. That is, the backlight 4 has a high reflectance surface that covers the light source and the like, and the reflected light reflected toward the backlight 4 is directed again toward the liquid crystal display panel LPN with almost no light loss on the high reflectance surface. Reflected. For this reason, the reflected light from the first color filter CF1, the second color filter CF2, and the third color filter CF3 is reused to improve the light use efficiency.

  FIG. 4 is a diagram illustrating an example of a reflection spectrum and a transmission spectrum of the color filter layer 30 illustrated in FIG. 3. The horizontal axis represents wavelength [nm], and the vertical axis represents the reflectance and transmittance of the color filter layer 30. The value on the vertical axis is a value normalized with the transmittance peak of the transmission spectrum CF3T of the third color filter CF3 as 1.

  The transmission spectrum CF1T of the first color filter CF1 has a transmittance peak in the vicinity of 540 nm. Further, the reflection spectrum CF1R of the first color filter CF1 has a reflectance bottom near 540 nm, and has a high reflectance in a wavelength range other than the same wavelength.

  The transmission spectrum CF2T of the second color filter CF2 has a transmittance peak in the vicinity of 470 nm. Further, the reflection spectrum CF2R of the second color filter CF2 has a reflectance bottom near 470 nm, and has a high reflectance in a wavelength range other than the same wavelength.

  The transmission spectrum CF3T of the third color filter CF3 has a transmittance peak in the vicinity of 610 nm. Further, the reflection spectrum CF3R of the third color filter CF3 has a reflectance bottom in the vicinity of 610 nm, and has a high reflectance in a wavelength range other than the same wavelength.

  Note that the transmission spectrum, the transmittance peak position, the reflection spectrum, and the reflectance bottom position of each of the first color filter CF1, the second color filter CF2, and the third color filter CF3 shown here are as follows. Adjustment is possible by changing the combination of the film thickness, thin film material, refractive index, and the like of the transmissive layer 31, the second semi-transmissive layer 32, and the transmissive layer 33.

  Next, a method for manufacturing the liquid crystal display panel LPN will be described with reference to FIGS.

  FIG. 5 is a cross-sectional view for explaining a process of forming the color filter layer 300 on the insulating substrate 100.

  The illustrated first mother substrate M1 forms a plurality of array substrates AR in a lump. The first mother substrate M1 is formed using a transparent insulating substrate 100 such as a glass substrate. The insulating substrate 100 corresponds to the first insulating substrate 10 constituting the array substrate AR. The color filter layer 300 is continuously formed over substantially the entire surface of the insulating substrate 100. The color filter layer 300 corresponds to the color filter layer 30 constituting the array substrate AR. That is, the color filter layer 300 includes the first color filter CF1, the second color filter CF2, and the third color filter CF3 as described above.

  Such a color filter layer 300 is formed as follows. That is, the first semi-transmissive layer 31 is formed by alternately laminating thin films of silicon oxide and silicon nitride on the insulating substrate 100. Then, the silicon nitride film is formed and patterned twice on the first semi-transmissive layer 31, and then the silicon nitride film is further formed to form the transmissive layer 33. Then, the second semi-transmissive layer 32 is formed by alternately laminating thin films of silicon oxide and silicon nitride on the transmissive layer 33.

  FIG. 6 is a cross-sectional view for explaining a process of forming alignment marks on the color filter layer 300.

  After the color filter layer 300 is formed on the insulating substrate 100, alignment marks and switching elements SW are formed on the color filter layer 300. In the illustrated example, the first alignment mark AM <b> 1 and the second alignment mark AM <b> 2 are formed on the color filter layer 300. The first alignment mark AM1 and the second alignment mark AM2 are formed on a specific color filter CFX in the color filter layer 300. The color filter CFX is one of the first color filter CF1, the second color filter CF2, and the third color filter CF3. Selection of the color filter CFX overlapping the alignment mark will be described later.

  The illustrated switching element SW corresponds to the first to third switching elements SW1 to SW3 of the array substrate AR. Although not shown in the drawings, on the color filter layer 300, respective insulating films corresponding to the first insulating film 11, the second insulating film 12, the third insulating film 13, and the fourth insulating film 14 are provided. Is formed. In the process of forming the polysilicon semiconductor layer of the switching element SW, polysilicon is formed and patterned, and in the process of forming the gate electrode, the source electrode, and the drain electrode of the switching element SW, molybdenum, Film formation and patterning of a metal material such as tungsten, titanium, and aluminum are performed. The alignment mark is formed simultaneously with the process of forming such a switching element SW. That is, the alignment mark is formed using polysilicon or a metal material such as molybdenum, tungsten, titanium, or aluminum. Selection of the material for forming the alignment mark will be described later.

  In the manufacturing process after the alignment mark is formed, based on the alignment mark, the presence or absence of the first mother substrate M1 is optically detected in the manufacturing apparatus, or the first mother substrate M1 is detected in the manufacturing apparatus. It is possible to match the positions and the position of the mask applied to the first mother substrate M1.

  FIG. 7 is a plan view of the first mother substrate M1 shown in FIG.

  A plurality of effective areas EF,... Are formed on the first mother substrate M1. Each of the effective areas EF corresponds to an area for forming the array substrate AR. The effective area EF includes an active area ACT and a peripheral area PRP. In the active area ACT, in addition to the above-described various insulating films and switching elements SW, pixel electrodes, alignment films, and the like are formed. In the peripheral area PRP, a mounting for mounting a driving IC chip and a flexible wiring board is provided. The portion MT and the like are formed, but detailed illustration is omitted. For example, the first alignment mark AM1 and the second alignment mark AM2 previously formed can be used when forming a contact hole in the fourth insulating film or patterning the pixel electrode.

  Further, “CTL” in the illustrated first mother substrate M1 is a planned cutting line for cutting the first mother substrate M1 when the array substrate AR is individually taken out from the first mother substrate M1 later. Each of the effective areas EF corresponds to an area surrounded by the planned cutting line CTL.

  In such a first mother substrate M1, alignment marks are formed in at least two places from the viewpoint of alignment accuracy. In the illustrated example, the first mother substrate M1 has a first alignment mark AM1 and a second alignment mark AM2 as alignment marks. The first alignment mark AM1 and the second alignment mark AM2 are formed in the periphery of the effective area EF. That is, neither the first alignment mark AM1 nor the second alignment mark AM2 in the illustrated example remains on the array substrate AR taken out from the first mother substrate M1, and is cut off when the first mother substrate M1 is cleaved. .

  As an example of the positions of the first alignment mark AM1 and the second alignment mark AM2, the first alignment mark AM1 is located at the first corner MC1 of the first mother substrate M1, and the second alignment mark AM2 is located on the first mother substrate M1. It is located at the second corner MC2. Note that the first alignment mark AM1 is positioned diagonally to the second alignment mark AM2, but the position of these alignment marks is not limited to the illustrated example. For example, the first alignment mark AM1 and the second alignment mark AM2 may be arranged along the long side or the short side of the first mother substrate M1, or arranged on the same straight line as the planned cutting line CTL. Also good. As a matter of course, the alignment mark may be added in addition to the first alignment mark AM1 and the second alignment mark AM2.

  Although not shown, on the one hand, a second mother substrate M2 for forming the counter substrate CT is prepared. The second mother substrate M2 has, for example, the same dimensions as the first mother substrate M1. Although not described in detail, an alignment mark is also formed on the second mother substrate M2.

  FIG. 8 is a plan view for explaining a process of drawing the sealing material SE on the first mother substrate M1 shown in FIG.

  That is, after the first mother substrate M1 having the above-described configuration is prepared, the sealing material SE having a shape surrounding the active area ACT of the effective area EF is formed on the first mother substrate M1. The sealing material SE having such a shape is formed, for example, by continuously drawing the sealing material using a dispenser. In the illustrated example, the sealing material SE is formed in a closed loop shape. When drawing such a sealing material SE, the first alignment mark AM1 and the second alignment mark AM2 formed in advance can be used.

  FIG. 9 is a plan view for explaining a step of dropping a liquid crystal material on the first mother substrate M1 shown in FIG.

  That is, after the sealing material SE having the above-described shape is formed, the liquid crystal material LM is dropped on the first mother substrate M1 on the inner side (including the active area ACT) surrounded by the sealing material SE for each of the effective regions EF. To do. At this time, the liquid crystal material LM is disposed on the first alignment film AL1 formed on the surface of each effective region EF. When the liquid crystal material LM is dropped, the previously formed first alignment mark AM1 and second alignment mark AM2 can be used.

  FIG. 10 is a plan view for explaining a process of bonding the first mother substrate M1 and the second mother substrate M2 shown in FIG.

  That is, after the liquid crystal material LM is dropped onto the first mother substrate M1, the first mother substrate M1 and the second mother substrate M2 are bonded together. At this time, the first mother substrate M1 is aligned based on the first alignment mark AM1 and the second alignment mark AM2 in a reduced pressure environment (or in a vacuum environment) such as in a vacuum chamber. Then, the second mother substrate M2 is aligned based on the third alignment mark AM3 and the fourth alignment mark AM4. As an example, the positions of the first mother substrate M1 and the second mother substrate M2 are adjusted so that the first alignment mark AM1 faces the third alignment mark AM3 and the second alignment mark AM2 faces the fourth alignment mark AM4. . Then, the second mother substrate M2 is overlaid on the sealing material SE and the liquid crystal material LM on the first mother substrate M1.

  Thereafter, the first mother substrate M1 and the second mother substrate M2 are pressurized by returning to atmospheric pressure from the reduced pressure environment. At this time, the applied sealing material SE is crushed, and the liquid crystal material LM spreads inside the sealing material SE. Then, the sealing material SE is cured, and the first mother substrate M1 and the second mother substrate M2 are bonded together. Accordingly, a mother substrate pair MX in which the liquid crystal layer LQ is formed between the first mother substrate M1 and the second mother substrate M2 is formed in each effective region EF.

  FIG. 11 is a plan view for explaining a process of taking out the liquid crystal display panel LPN from the mother substrate pair MX shown in FIG.

  That is, after the mother substrate pair MX is formed, both the first mother substrate M1 and the second mother substrate M2 are cleaved by the cleaving line CTL. Thereby, the array substrate AR is taken out from the first mother substrate M1, and the counter substrate CT is taken out from the second mother substrate M2, and the liquid crystal display panel in which the liquid crystal layer LQ is held between the array substrate AR and the counter substrate CT. LPN is manufactured.

  Next, the method for detecting the alignment mark will be described using the first alignment mark AM1 as an example.

  FIG. 12 is a plan view showing an example of the first alignment mark AM1 disposed on the first mother substrate M1.

  In the illustrated example, the rectangular first alignment marks AM1 are arranged in a 2 × 2 matrix, but the present invention is not limited to this example.

  FIG. 13 is a cross-sectional view for explaining a process of detecting the first alignment mark AM1.

  In the illustrated example, the reference light emitted from the light source is emitted toward the first alignment mark AM1, and based on the reference light, the reflected light from the first alignment mark AM1 and the reflected light from the color filter CFX. The first alignment mark AM1 is detected. Upon detection of the first alignment mark AM1, the reflected light from the first alignment mark AM1 and the reflected light from the color filter CFX are received by the light receiving unit. Note that both the light source and the light receiving portion are located on the side facing the first alignment mark AM1. The light receiving unit outputs a signal corresponding to the intensity of the received reflected light. At this time, the difference between the reflectance at the first alignment mark AM1 and the reflectance at the color filter CFX with respect to the reference light (or the difference between the reflected light intensity from the first alignment mark AM1 and the reflected light intensity from the color filter CFX). Difference) creates contrast. That is, the first alignment mark AM1 on the color filter CFX is detected by processing the signal output from the light receiving unit. The detection sensitivity of the first alignment mark AM1 increases as the contrast of the first alignment mark AM1 and the color filter CFX with respect to the reference light increases (that is, the reflectance of the first alignment mark AM1 and the reflectance of the color filter CFX). The greater the difference, the better.

  Examples of the light source applied in such a detection process include a red laser light source that emits red light as reference light, a green laser light source that emits green light as reference light, and a white light source that emits white light as reference light. .

  Hereinafter, an optimal combination of the material of the first alignment mark AM1 and the color filter CFX that can improve the detection sensitivity of the first alignment mark AM1 will be discussed.

[Embodiment 1]
In the first embodiment, a case where a red laser light source is applied as a light source will be described. For example, the red laser light source emits red light having a wavelength of 632 nm as reference light. When titanium was applied as the material of the first alignment mark AM1, the reflectance of the first alignment mark AM1 with respect to the reference light was 58%. When molybdenum was applied as the material of the first alignment mark AM1, the reflectance at the first alignment mark AM1 with respect to the reference light was 45%. When polysilicon is applied as the material of the first alignment mark AM1, the reflectance of the first alignment mark AM1 with respect to the reference light is 41%. That is, when titanium was applied as the material of the first alignment mark AM1, a relatively high reflectance with respect to the reference light was obtained.

  On the other hand, when the first color filter (green color filter) CF1 is applied as the color filter CFX, the reflectance of the color filter CFX with respect to the reference light is 88%. When the second color filter (blue color filter) CF2 was applied as the color filter CFX, the reflectance of the color filter CFX with respect to the reference light was 85%. When the third color filter (red color filter) CF3 was applied as the color filter CFX, the reflectance of the color filter CFX with respect to the reference light was almost 0%. Note that the reflectance of the first mother substrate M1 with respect to the reference light when the color filter CFX was not arranged was 4%. That is, when the third color filter CF3 is applied as the color filter CFX, a relatively low reflectance is obtained with respect to the reference light, and the reflectance at the first mother substrate M1 when the color filter CFX is not disposed. It was confirmed that it is almost equivalent.

  Thus, when detecting the first alignment mark AM1 formed on the color filter CFX, when a red laser light source is applied as the light source, for example, titanium is applied as the material of the first alignment mark AM1. A combination in which the third color filter CF3 is applied as the color filter CFX is preferable. With such a combination, it is possible to improve the contrast of the first alignment mark AM1 and the color filter CFX with respect to the reference light.

  That is, when titanium is applied as the material of the first alignment mark AM1, the third color filter CF3 is applied as compared with the case where the first color filter CF1 and the second color filter CF2 are applied as the color filter CFX. In this case, it is possible to obtain a higher contrast with respect to the reference light. Therefore, according to the above combination, it is possible to improve the detection sensitivity of the first alignment mark AM1. Accordingly, it is possible to reliably detect the presence or position of the first mother substrate M1 based on the first alignment mark AM1 and to perform alignment, and it is possible to suppress a decrease in manufacturing yield.

[Embodiment 2]
In the second embodiment, a case where a green laser light source is applied as a light source will be described. The green laser light source emits, for example, green light having a wavelength of 532 nm as reference light. When titanium was applied as the material of the first alignment mark AM1, the reflectance of the first alignment mark AM1 with respect to the reference light was 57%. When molybdenum was applied as the material of the first alignment mark AM1, the reflectance at the first alignment mark AM1 with respect to the reference light was 40%. When polysilicon is applied as the material of the first alignment mark AM1, the reflectance of the first alignment mark AM1 with respect to the reference light is 39%. That is, when titanium was applied as the material of the first alignment mark AM1, a relatively high reflectance with respect to the reference light was obtained.

  On the other hand, when the first color filter (green color filter) CF1 is applied as the color filter CFX, the reflectance of the color filter CFX with respect to the reference light is almost 0%. When the second color filter (blue color filter) CF2 was applied as the color filter CFX, the reflectance of the color filter CFX with respect to the reference light was 92%. When the third color filter (red color filter) CF3 was applied as the color filter CFX, the reflectance of the color filter CFX with respect to the reference light was 91%. Note that the reflectance of the first mother substrate M1 with respect to the reference light when the color filter CFX was not arranged was 4%. That is, when the first color filter CF1 is applied as the color filter CFX, a relatively low reflectance is obtained with respect to the reference light, and the reflectance at the first mother substrate M1 when the color filter CFX is not disposed. It was confirmed that it is almost equivalent.

  Thus, when detecting the first alignment mark AM1 formed on the color filter CFX, when a green laser light source is applied as the light source, for example, titanium is applied as the material of the first alignment mark AM1. A combination in which the first color filter CF1 is applied as the color filter CFX is preferable. With such a combination, it is possible to improve the contrast of the first alignment mark AM1 and the color filter CFX with respect to the reference light.

  That is, when titanium is applied as the material of the first alignment mark AM1, the first color filter CF1 is applied as compared with the case where the second color filter CF2 or the third color filter CF3 is applied as the color filter CFX. In this case, it is possible to obtain a higher contrast with respect to the reference light. In the second embodiment, the same effect as that of the first embodiment can be obtained.

[Embodiment 3]
In the third embodiment, a case where a white light source is applied as a light source will be described. The case where the white light source is applied here corresponds to, for example, imaging an alignment mark with a television camera or the like, and the light source that positively emits white light toward the alignment mark is not necessarily provided. Absent.

  When titanium was applied as the material of the first alignment mark AM1, the reflectance of the first alignment mark AM1 with respect to the reference light (white light) was 55%. When molybdenum was applied as the material of the first alignment mark AM1, the reflectance at the first alignment mark AM1 with respect to the reference light was 40%. When polysilicon is applied as the material of the first alignment mark AM1, the reflectance at the first alignment mark AM1 with respect to the reference light is 40%.

  On the other hand, when the first color filter (green color filter) CF1 was applied as the color filter CFX, the reflectance of the color filter CFX with respect to the reference light was 58%. When the second color filter (blue color filter) CF2 was applied as the color filter CFX, the reflectance of the color filter CFX with respect to the reference light was 45%. When the third color filter (red color filter) CF3 was applied as the color filter CFX, the reflectance of the color filter CFX with respect to the reference light was 67%. Note that the reflectance of the first mother substrate M1 with respect to the reference light when the color filter CFX was not arranged was 4%.

  Thus, when detecting the first alignment mark AM1 formed on the color filter CFX, when a white light source is applied, for example, molybdenum or polysilicon is applied as the material of the first alignment mark AM1, A combination in which the third color filter CF3 is applied as the color filter CFX is preferable. With such a combination, it is possible to improve the contrast of the first alignment mark AM1 and the color filter CFX with respect to the reference light.

  That is, when molybdenum or polysilicon is applied as the material of the first alignment mark AM1, the third color filter CF3 is compared with the case where the first color filter CF1 or the second color filter CF2 is applied as the color filter CFX. When is applied, higher contrast can be obtained with respect to the reference light. In the third embodiment, the same effect as that of the first embodiment can be obtained.

  In the first to third embodiments, the preferred combination of the material of each first alignment mark AM1 and the color filter CFX has been described. However, any combination that can obtain a relatively high contrast is used in the above-described combination. It is not limited.

  Next, another method for detecting alignment marks will be described.

  FIG. 14 is a cross-sectional view for explaining another process of detecting the first alignment mark AM1.

  In the illustrated example, the reference light emitted from the light source is irradiated toward the first alignment mark AM1, and among the reference light, the transmitted light transmitted through the first alignment mark AM1 and the transmitted light transmitted through the color filter CFX. Based on this, the first alignment mark AM1 is detected. Upon detection of the first alignment mark AM1, the transmitted light transmitted through the first alignment mark AM1 and the transmitted light transmitted through the color filter CFX are received by the light receiving unit. The light source is located on the side facing the first alignment mark AM1, and the light receiving part is located on the side facing the insulating substrate 100 (that is, the side opposite to the first alignment mark AM1). The light receiving unit outputs a signal corresponding to the intensity of the received transmitted light. At this time, the difference between the transmittance at the first alignment mark AM1 and the transmittance at the color filter CFX with respect to the reference light (or the difference between the transmitted light intensity from the first alignment mark AM1 and the transmitted light intensity from the color filter CFX). Difference) creates contrast. That is, the first alignment mark AM1 on the color filter CFX is detected by processing the signal output from the light receiving unit. The detection sensitivity of the first alignment mark AM1 increases as the contrast of the first alignment mark AM1 and the color filter CFX with respect to the reference light increases (that is, the transmittance of the first alignment mark AM1 and the transmittance of the color filter CFX). The greater the difference, the better.

  Various light sources that can be applied in such a detection step can be applied. Here, as an example, a case where a red laser light source that emits red light as reference light is applied will be described.

[Embodiment 4]
In the fourth embodiment, a case where a red laser light source similar to that described in the first embodiment is applied as the light source will be described. When titanium was applied as the material of the first alignment mark AM1, the transmittance of the first alignment mark AM1 with respect to the reference light was almost 0%. When molybdenum was applied as the material of the first alignment mark AM1, the transmittance of the first alignment mark AM1 with respect to the reference light was almost 0%. When polysilicon is used as the material of the first alignment mark AM1, the transmittance of the first alignment mark AM1 with respect to the reference light is 80%. That is, when titanium or molybdenum is applied as the material of the first alignment mark AM1, a relatively low transmittance can be obtained with respect to the reference light, whereas when polysilicon is applied, the transmittance is relatively low with respect to the reference light. A high transmittance was obtained.

  On the other hand, when the first color filter (green color filter) CF1 is applied as the color filter CFX, the transmittance of the color filter CFX with respect to the reference light is 11%. When the second color filter (blue color filter) CF2 was applied as the color filter CFX, the transmittance of the color filter CFX with respect to the reference light was 14%. When the third color filter (red color filter) CF3 was applied as the color filter CFX, the transmittance of the color filter CFX with respect to the reference light was 95%. Note that the transmittance of the first mother substrate M1 with respect to the reference light when the color filter CFX was not arranged was 95%. That is, when the third color filter CF3 is applied as the color filter CFX, a relatively high transmittance can be obtained with respect to the reference light, and the transmittance of the first mother substrate M1 when the color filter CFX is not disposed. It was confirmed that it is almost equivalent. Further, when the first color filter CF1 and the second color filter CF2 were applied as the color filter CFX, a relatively low transmittance with respect to the reference light was obtained.

  Thus, when the first alignment mark AM1 formed on the color filter CFX is detected, when a red laser light source is applied as the light source, for example, titanium or molybdenum is used as the material of the first alignment mark AM1. A combination in which the third color filter CF3 is applied as the color filter CFX is suitable. A combination in which polysilicon is applied as the material of the first alignment mark AM1 and the first color filter CF1 or the second color filter CF2 is applied as the color filter CFX is also suitable. With such a combination, it is possible to improve the contrast of the first alignment mark AM1 and the color filter CFX with respect to the reference light. Therefore, according to the above combination, it is possible to improve the detection sensitivity of the first alignment mark AM1. Accordingly, it is possible to reliably detect the presence or position of the first mother substrate M1 based on the first alignment mark AM1 and to perform alignment, and it is possible to suppress a decrease in manufacturing yield.

  As described above, in this embodiment, the material of the alignment mark on the color filter layer constituted by the interference color filter is selected in consideration of the reflectance and transmittance with respect to the reference light from the light source applied at the time of detection. Is done. The material for forming the alignment mark can be selected from materials for forming the switching element, for example. That is, the alignment mark is formed in the same process as the polysilicon semiconductor layer, the gate electrode, or the source electrode of the switching element. For this reason, it is not necessary to prepare a separate process for forming the alignment mark. Further, the material of the alignment mark can be selected in such a combination that the contrast of the alignment mark becomes high in consideration of the reflectance and transmittance of the color filter layer serving as the base of the alignment mark with respect to the reference light. For this reason, it becomes possible to improve the detection sensitivity of the alignment mark. Thereby, it is possible to improve the manufacturing yield.

  Next, a modification of this embodiment will be described.

  FIG. 15 is a plan view of another first mother substrate M1 applicable to this embodiment.

  The example shown in FIG. 15 is different from the example shown in FIG. 7 in that an alignment mark is added in the effective area EF in addition to the first alignment mark AM1 and the second alignment mark AM2. . The alignment mark added here is, for example, a mark for the planned cutting line CTL, or a mark for mounting a signal supply source on the mounting portion MT of the liquid crystal display panel LPN taken out from the mother substrate pair MX. It is.

  For example, a pair of fifth alignment marks AMS1 sandwiching the first cutting planned line CTL1 is formed near the upper end of the first cutting planned line CTL1, and the first cutting planned line is formed near the lower end of the first cutting planned line CTL1. A pair of sixth alignment marks AMS12 sandwiching CTL1 are formed. Thus, when the first mother substrate M1 is cut along the first cutting planned line CTL1, alignment can be performed based on the fifth alignment mark AMS1 and the sixth alignment mark AMS12.

  A pair of seventh alignment marks AMS21 sandwiching the second cutting planned line CTL2 is formed near the left end of the second cutting planned line CTL2, and the second cutting planned line is formed near the right end of the second cutting planned line CTL2. A pair of eighth alignment marks AMS22 sandwiching CTL2 are formed. As a result, when the first mother substrate M1 is cut along the second cutting plan line CTL2, alignment can be performed based on the seventh alignment mark AMS21 and the eighth alignment mark AMS22.

  Although not shown, alignment marks may be formed in the vicinity of the end portions of other planned cutting lines, and alignment marks may be formed at positions where the planned cutting lines CTL intersect.

  A ninth alignment mark AMS3 is formed in the peripheral area PRP of the first effective area EF1. Therefore, after the first effective area EF1 is taken out from the first mother substrate M1 as the array substrate, the ninth alignment mark AMS3 remains on the array substrate. Thereby, when mounting a signal supply source in mounting part MT, it can align based on the 9th alignment mark AMS3.

  Although not shown, an alignment mark similar to the ninth alignment mark AMS3 may be formed in each of the other effective areas EF.

  Each alignment mark formed in the effective area EF remains on the array substrate taken out from the first mother substrate M1.

  As described above, according to this embodiment, it is possible to provide a method for manufacturing a liquid crystal display device capable of suppressing a decrease in manufacturing yield.

  In addition, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

LPN ... liquid crystal display panel AR ... array substrate CT ... counter substrate LQ ... liquid crystal layer 30 ... color filter layer 31 ... first semi-transmissive layer 32 ... second semi-transmissive layer 33 ... transmissive layer CF1 ... first color filter CF2 ... second Color filter CF3 ... Third color filter AM1 ... First alignment mark AM2 ... Second alignment mark

Claims (6)

Forming a first color filter having a transmittance peak in a first wavelength range and a second color filter having a transmittance peak in a second wavelength range different from the first wavelength range on an insulating substrate;
Forming an alignment mark on the first color filter;
A method for manufacturing a liquid crystal display device, wherein the alignment mark is detected by irradiating the alignment mark with reference light,
A first contrast of the alignment mark and the first color filter with respect to the reference light is higher than a second contrast of the alignment mark and the second color filter with respect to the reference light. Production method.   2. The method of manufacturing a liquid crystal display device according to claim 1, wherein the first color filter and the second color filter are Fabry-Perot interference color filters using optical interference.   3. The method of manufacturing a liquid crystal display device according to claim 1, wherein the alignment marks are formed at least at two locations on the first color filter.   4. The method of manufacturing a liquid crystal display device according to claim 1, wherein the alignment mark is formed in a peripheral portion of an effective area for forming the array substrate.   5. The alignment mark according to claim 1, wherein the alignment mark is detected based on reflected light from the alignment mark and reflected light from the first color filter among the reference light. 6. A method for manufacturing a liquid crystal display device.   5. The alignment mark according to claim 1, wherein the alignment mark is detected based on transmitted light transmitted through the alignment mark and transmitted light transmitted through the first color filter among the reference light. 6. The manufacturing method of the liquid crystal display device of description.

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