JP5756813B2 - Substrate exposure method - Google Patents

Description

The present invention relates to a display panel substrate and a substrate exposure method. More specifically, the present invention relates to a display panel substrate suitable for scanning exposure performed in a photo-alignment processing step of an alignment film, and an exposure method for the substrate.

The alignment film formed on the surfaces of the TFT array substrate and the color filter substrate of the liquid crystal display panel is subjected to an alignment process in order to align liquid crystal molecules in a predetermined direction. Conventionally, rubbing with a fiber material has been generally used as a method for this alignment treatment, but recently, a photo-alignment treatment has been used as an alternative alignment treatment method.

The photo-alignment process is a process that gives predetermined alignment characteristics to the surface of the alignment film by irradiating the alignment film with light from a predetermined direction. In this specification, “light” is not limited to visible light, but includes ultraviolet light (ultraviolet light) that is an electromagnetic wave having a shorter wavelength than visible light. As an exposure method in the photo-alignment treatment, for example, a method in which a mask provided with an opening having a predetermined shape is arranged so as to cover the entire surface of the substrate, and light is irradiated from above the mask.

In such an exposure method, it is necessary to increase the size of the mask as the substrate size increases, leading to an increase in the cost of the mask. Further, when the mask is enlarged, the position of the opening is likely to be displaced due to bending.

On the other hand, an exposure method has been proposed in which a substrate is moved while irradiating light on a partial region of the substrate surface using a small mask having slit-shaped openings (Patent Document 1). 2). According to this exposure method, a specific region on the substrate surface is exposed in a stripe shape. Also, in this exposure method, while moving the substrate while irradiating light, the pattern formed on the surface of the substrate is photographed, and the position of the actual illumination is monitored using the photographed image. To do. As a result, the area that is actually exposed does not deviate from the area to be exposed, and correction is performed when the area does not deviate.

When performing such an exposure method, an alignment mark is formed on the substrate so that the exposure can be performed with high precision in the vicinity of the exposure start position of the substrate. In Patent Document 1, an alignment mark for correcting in advance the position and angle of a mask with respect to a substrate on the outside of an area where a pattern of picture elements is formed in a lattice pattern and in the vicinity of the area of the substrate to be exposed. Forming a dummy pattern is disclosed.

JP 2007-41175 A International Publication No. 2007/113933

The exposure start position should be exposed even when the alignment mark is arranged outside the area where the picture element pattern is formed in a lattice pattern and just around the periphery of the area as in Patent Document 1. There is a possibility of further devising because the exposure position shifts out of the region and is called “following failure”.

The present invention has been made in view of the above-described present situation, and an object thereof is to provide a display panel substrate and a substrate exposure method capable of accurately starting exposure from a predetermined position in a predetermined direction. Is.

The present inventors have disclosed an exposure method (in other words, scanning exposure) in which a substrate is moved while irradiating light onto a partial region of the substrate surface using a small mask having slit-like openings formed therein. As a result of various studies, attention was paid to the fact that exposure may not be performed accurately near the exposure start position of the substrate. That is, the present inventors recognize the alignment mark in an aspect in which the alignment mark is arranged outside the region where the pixel pattern is formed in a lattice shape (in other words, the exposure region) and in the immediate vicinity of the exposure region. It has been found that the exposure area may reach under the mask after the mask correction is completed. Therefore, the present inventors can complete the adjustment of the position and orientation of the mask before the exposure area reaches under the mask by arranging the center of the alignment mark at a position 2 mm or more away from the display area. Thus, the present invention has been achieved as a result of conceiving that exposure can be accurately started from a predetermined position in a predetermined direction and the above-mentioned problems can be solved brilliantly.

That is, the present invention is a display panel substrate having a display area in which a plurality of picture elements are arranged and a frame area adjacent to the display area,
An alignment mark is provided in the frame area,
The center of the alignment mark is a display panel substrate located at a position 2 mm or more away from the display area.

The display panel substrate of the present invention is suitable as a substrate to which scanning exposure is applied, and the alignment mark is preferably used for positioning during scanning exposure. For example, exposure accuracy can be improved by configuring an exposure system that reads information on the position and orientation of the alignment mark and adjusts the position and orientation of the photomask.

The present invention is also a substrate exposure method in which the display panel substrate placed on the stage is scanned and exposed by an exposure machine including a light source, a photomask, a stage, and an imaging device,
In the scanning exposure, at least one of the display panel substrate and the photomask is moved, and light emitted from the light source is irradiated to the display region through a light transmitting portion provided in the photomask. Yes,
The substrate exposure method is as follows:
Before scanning and exposing the inside of the display area, information on the position and orientation of the alignment mark is read by the imaging device,
It is also a substrate exposure method in which the position and / or orientation of the photomask is adjusted based on the information while the photomask moves from the frame area to the display area.

In the present specification, the frame region is not particularly limited as long as it is a region excluding the display region in the display panel substrate, and includes, for example, an outer peripheral region of the display panel substrate. When the display panel substrate is a mother glass substrate and a plurality of display areas are arranged in the display panel substrate, the frame area may include an area between the plurality of display areas. , It does not have to be included.

The center of the alignment mark is preferably at a position within 50 mm from the display area. If the center of the alignment mark is placed more than 50 mm away from the display area, even if the mask position and orientation are adjusted to the optimum state based on the alignment mark, the mask position and orientation when reaching the display area is optimal. There is a possibility that it is out of the normal state.

As an embodiment of the present invention, the display panel substrate may include a wiring in the frame region, and the alignment mark may be disposed in a region between the wiring and the display region. According to this embodiment, it is possible to prevent the distance between the display area and the alignment mark from becoming too large, and to prevent the wiring in the frame area from being misidentified as the alignment mark.

The alignment mark is not particularly limited as long as it can read information on the position and orientation by the imaging device. For example, as an embodiment of the present invention, the alignment mark may be formed by a light shielding member extending in a row. The pattern extending in a row is effective for obtaining information on both the position and the orientation, and the light shielding body is effective for obtaining information by the imaging device. Moreover, since it is a simple shape, there is little possibility that the imaging apparatus will fail to recognize.

As one form of this invention, the said alignment mark has the form extended in parallel with the alignment pattern in a display area. According to this aspect, the imaging apparatus can recognize the alignment pattern in the display area accurately and easily using the alignment mark provided in the frame area as a clue. The alignment mark and the alignment pattern extending in parallel mean that the angle formed by the straight line portion included in the alignment mark and the straight line portion included in the alignment pattern is less than 3 °. , Preferably less than 1 °.

As one form of this invention, the said alignment mark has a form which has a 150 micrometers or more linear part parallel to the alignment pattern in a display area. If the alignment mark is provided with a straight line portion having the same length as that of the picture element, information regarding the position and orientation can be accurately determined by the imaging device.

As one form of this invention, the said alignment mark is arrange | positioned in parallel with the alignment pattern in a display area, and the form arrange | positioned at dotted line form is mentioned. Also in this form, the imaging apparatus can recognize the alignment pattern in the display area accurately and easily using the alignment mark provided in the frame area as a clue.

As one form of this invention, the said board | substrate for display panels is a board | substrate used for a liquid crystal display panel, and the form provided with an alignment film is mentioned. Since the exposure state in the photo-alignment process is strongly related to the display quality of the liquid crystal display device, if the exposure accuracy in the photo-alignment process is improved by providing the alignment mark in the frame region, the liquid crystal display device The display quality can be improved.

According to the display panel substrate and the substrate exposure method using the display panel substrate according to the present invention, the exposure can be accurately started in a predetermined direction from a predetermined position. Can be accurately exposed.

In the exposure method which concerns on Embodiment 1, it is a perspective schematic diagram which shows the state before the exposure to a display area. In the exposure method which concerns on Embodiment 1, it is a perspective schematic diagram which shows the state during the exposure to a display area. 4 is an enlarged schematic plan view showing alignment marks formed on a display panel substrate according to Embodiment 1 and end portions of a display region corresponding to an array substrate. FIG. In the exposure method which concerns on Embodiment 1, it is a plane schematic diagram which shows the state before adjusting the direction of the board | substrate for display panels, and the centerline of the translucent part provided in the photomask in parallel. FIG. 3 is a side view conceptually showing the configuration of the main part of the exposure apparatus according to Embodiment 1. It is the figure which showed typically the photo-alignment process with respect to the array substrate using the exposure method which concerns on Embodiment 1. FIG. It is the figure which showed typically the optical orientation process with respect to the color filter substrate using the exposure method which concerns on Embodiment 1. FIG. FIG. 8 is a diagram schematically showing the orientation direction of liquid crystal molecules in each pixel in a liquid crystal display panel configured by bonding the array substrate shown in FIG. 6 and the color filter substrate shown in FIG. 7. FIG. 3 is a schematic plan view showing a configuration of a photomask for an array substrate used in the exposure method according to Embodiment 1. It is the figure which showed the relationship of the dimension and position of the photomask of FIG. 9, and the pattern formed in the array substrate. It is the figure which showed the relationship of the dimension and position of the photomask for color filter substrates used for the exposure method which concerns on Embodiment 1, and the pattern formed in the color filter substrate. FIG. 5 is a schematic plan view showing an enlarged alignment mark formed on a display panel substrate according to Embodiment 2. FIG. 6 is a schematic plan view illustrating an enlarged alignment mark formed on a display panel substrate according to Embodiment 3. FIG. 10 is a schematic plan view illustrating an enlarged alignment mark formed on a display panel substrate according to Embodiment 4.

Embodiment 1
A display panel substrate according to the present embodiment and an exposure method using the substrate will be described with reference to FIGS.

FIG. 1 is a schematic perspective view illustrating a state before exposure of a display area in the exposure method according to the first embodiment. FIG. 2 is a state during exposure of the display area in the exposure method according to the first embodiment. FIG.

The substrate exposure method according to the present embodiment uses a so-called “scanning exposure” method. As shown in FIGS. 1 and 2, the mother glass substrate 10 is used while irradiating the surface of the mother glass substrate 10 with ultraviolet rays through the light transmitting portion of the mask 50 using a mask 50 having a slit-like light transmitting portion. It is to be moved. The arrows in FIGS. 1 and 2 indicate the moving direction of the mother glass substrate 10. The exposure method according to this embodiment is applied to a step of performing a photo-alignment process on an alignment film formed on the mother glass substrate 10.

The mother glass substrate 10 is for manufacturing an array substrate or a color filter substrate of a liquid crystal display panel, and six array substrates or color filter substrates can be cut out from one mother glass substrate 10. In this embodiment, the mother glass substrate 10 is described as an example of the display panel substrate. However, the display panel substrate of the present invention may be a single array substrate or a single color filter substrate.

The mother glass substrate 10 is provided with six display areas 11 corresponding to each array substrate or color filter substrate. In the display region corresponding to the array substrate, the source signal lines and the gate signal lines intersecting each other are formed in a mesh pattern, and the thin film transistor and the pixel electrode are formed in each pixel region partitioned by the source signal line and the gate signal line. Is formed. In the display area corresponding to the color filter substrate, a black matrix is formed in a mesh shape, and a color filter is formed in each pixel area partitioned by the black matrix. An alignment film to which a photo-alignment process can be applied is formed on the surface of the mother glass substrate.

An alignment mark 13 is provided in the outer peripheral region (frame region) of the mother glass substrate 10. This alignment mark 13 is used to adjust the position and orientation of the mask 50 in advance in accordance with the position and orientation of the substrate 10 before starting the exposure to the display area 11 in the execution of the exposure method according to the present embodiment. belongs to. By such adjustment, the mask 50 is not suddenly largely displaced at the time of starting exposure on the display area 11, the accuracy of the exposure position can be improved, and the occurrence of exposure unevenness can be prevented. In addition, since the pattern in the display area 11 is complicated, it may fail to recognize a predetermined follow-up pattern (alignment pattern) in the display area 11 when exposure to the display area 11 is started. Since the pre-adjustment is performed by the alignment mark 13 arranged at the position, the capturing accuracy of the follow-up pattern (alignment pattern) can be improved.

The center of the alignment mark 13 is provided at a position 2 mm to 50 mm away from the display area 11. According to the experiment of the present inventor, when the alignment mark 13 is arranged adjacent to the display area 11 (the length of the alignment mark 13 is 2 mm, and the distance between the center of the alignment mark 13 and the boundary of the display area 11 is 1 mm), the follow-up pattern (alignment pattern) in the display area 11 could not be accurately recognized at a rate of 80% or more. Further, when the alignment mark 13 is arranged at a position 52 mm away from the display area 11, the rate at which the tracking pattern (alignment pattern) in the display area 11 cannot be accurately recognized is about 1 to 2%. Met. However, it is often difficult to provide a frame region of 50 mm or more in order to arrange the alignment mark 13 in consideration of other design elements of the display device substrate. Further, in the above experimental results, the defect rate is about 1 to 2%. However, if the distance between the center of the alignment mark 13 and the display area 11 becomes too large, the defect rate may increase.

Further, the amount of deviation when reading the alignment mark 13 (the amount that needs to be corrected at that time) is about 50 μm at the maximum. On the other hand, the operation status of a general apparatus is, for example, that the maximum moving speed of the mask during alignment is 1 mm / sec, the acceleration is 25 mm / sec ² , and the substrate transport speed is 90 mm / sec. From this condition, it can be said that the distance between the center of the alignment mark 13 and the display area 11 is 6.3 mm in order to correct the deviation of 50 μm. However, for example, the conveyance speed of the substrate is not limited to 90 mm / sec, and a general range is 50 mm / sec to 200 mm / sec. For these reasons, the lower limit of the distance between the center of the alignment mark 13 and the display region 11 is preferably 5 mm or more, and more preferably 8 mm or more. The upper limit of the distance between the center of the alignment mark 13 and the display area 11 is preferably 20 mm or less. Moreover, it is preferable that the alignment mark 13 is arrange | positioned in the area | region between the wiring in a frame area | region, and a display area from a viewpoint of improving a recognition rate.

The dimension of the alignment mark 13 is not particularly limited. The width of the alignment mark 13 is preferably 10 μm or more, and preferably 50 μm or less. The length of the alignment mark 13 in the substrate transport direction is preferably 150 μm or more, more preferably 500 μm or more, and preferably 10 mm or less. From the viewpoint of causing the exposure machine to recognize the alignment mark 13, the length of the alignment mark 13 in the substrate transport direction is usually 1 mm or less.

FIG. 3 is an enlarged schematic plan view showing the alignment marks formed on the display panel substrate according to the first embodiment and the end of the display area corresponding to the array substrate. As shown in FIG. 3, if the mother glass substrate to be exposed is for manufacturing an array substrate, a rectangular pattern having a width of about 15 μm and a length of about 500 μm is formed from 2 mm to 50 mm from the display area 11 corresponding to the array substrate. The alignment mark 13 is formed at a distant position. Since the rectangular pattern 13 has a simple shape, it is advantageous in that it is less likely to be recognized by the imaging apparatus. The rectangular pattern 13 is formed in the same process as the source signal line 15 and is made of the same material as the source signal line 15.

The two source signal lines 15 are arranged as one set, and the rectangular pattern 13 is formed at a position where the center line coincides with the center line of the one set of source signal lines 15 formed in the display region 11. Is done. Since the rectangular pattern 13 and the center line of the set of source signal lines 15 coincide with each other, the imaging device is prevented from failing to capture the set of source signal lines 15. The imaging apparatus uses a set of source signal lines 15 as a follow-up pattern (alignment pattern) in the display area 11, whereby accurate exposure is performed on the entire display area 11.

If the mother glass substrate to be exposed is for manufacturing a color filter substrate, a rectangular pattern having a width of about 15 μm and a length of about 500 μm is positioned 2 mm to 50 mm away from the display area 11 corresponding to the color filter substrate. The alignment mark 13 is formed. The rectangular pattern 13 is formed in the same process as the black matrix, and its center line is formed at a position that coincides with the center line of the black matrix formed in the display area 11. The imaging apparatus uses a black matrix as a follow-up pattern (alignment pattern) in the display area 11, whereby accurate exposure is performed on the entire display area 11.

As described above, in the display panel substrate according to the present embodiment, the alignment mark 13 can be formed together in the step of forming the source signal line 15 or the black matrix. Therefore, it is not necessary to add a special process for forming the alignment mark 13, and the cost and time for manufacturing the substrate are not increased.

FIG. 4 is a schematic plan view showing a state before adjusting the orientation of the display panel substrate and the center line of the translucent portion provided on the photomask in the exposure method according to the first embodiment. As shown in FIG. 4, the substrate 10 is inclined with respect to the transport direction (see the arrow in FIG. 4), and is not parallel to the center line of the slit-like light transmitting portion of the photomask 50. In the state, the display area 11 cannot be exposed along the arrangement direction of the picture elements provided on the substrate 10. If the length of the substrate in the conveyance direction is 2460 mm, a positional deviation of about 250 μm may actually occur between the front end and the rear end of the substrate, whereas the follow-up pattern (alignment pattern) has a predetermined position. If it deviates 5 μm or more from the distance, it becomes difficult to recognize.

On the other hand, in the present embodiment, before the display area 11 of the substrate 10 reaches below the photomask, the position and orientation of the alignment mark 13 positioned on the photomask 50 side 2 mm to 50 mm from the display area 11 are determined. Check. Then, based on the confirmation result, the conveyance direction of the substrate 10 and the center line of the slit-like light transmitting portion of the photomask 50 are at a desired angle (for example, parallel) without stopping the conveyance of the substrate 10. The position and angle of at least one of the substrate 10 and the photomask 50 are adjusted. Thus, since exposure can be accurately started from a predetermined position in a predetermined direction, exposure can be performed with high accuracy even at the end of the display area 11 that is the exposure start position of the substrate.

FIG. 5 is a side view conceptually showing the structure of the main part of the exposure apparatus according to the first embodiment. The exposure machine includes an exposure unit 51 that irradiates the substrate 10 with ultraviolet rays, and a stage 55 for placing and moving the substrate 10.

The exposure unit 51 includes an ultraviolet light source that emits ultraviolet light, and is configured to irradiate the surface of the substrate 10 with ultraviolet light at a predetermined irradiation angle via the mask 50. What is necessary is just to select a light source suitably according to irradiation object, and the light source which emits visible light may be sufficient.

Each exposure unit 51 includes an imaging unit 53, a storage unit, a collation unit, and a mask moving unit. The imaging unit 53 can photograph the surface of the substrate 10. For example, a CCD camera or the like can be applied. The storage means can store a reference image serving as a reference for exposure alignment. The collating unit compares and collates the image captured by the image capturing unit 53 with the reference image, and calculates a difference between the actual exposure position and the position to be exposed. The mask moving unit corrects the position and / or angle of the mask 50 based on the shift calculation result by the collating unit. Note that the collating means can similarly correct the position and / or angle of the mask 50 by a method of comparing and collating the result of imaging the substrate 10 and the result of imaging the mask 50 instead of using the reference image. it can.

The mask 50 is, for example, a plate-like member, and a light-transmitting portion having a predetermined dimension is provided at a predetermined location. Therefore, when the substrate 10 is transported and passes directly under the mask 50, only the region that has passed directly under the light transmitting portion of the mask 50 is exposed. As a result, a predetermined elongated linear area on the surface of the substrate 10 is exposed. The light transmitting portion is not particularly limited as long as it can transmit light (ultraviolet rays in the present embodiment). For example, the light transmitting portion may be an opening provided in a mask or a portion where a transparent film is formed. Also good.

Further, as shown in FIG. 1, the exposure apparatus includes a plurality of masks 50 (in other words, exposure units 51). Then, the exposure units 51 are arranged perpendicular to the traveling direction of the substrate 10. Thereby, it can expose by one scan over the full width of the board | substrate 10. FIG. Each exposure unit 51 can perform the above operation independently.

Next, an operation of performing the exposure method according to the embodiment of the present invention on the substrate according to the embodiment using an exposure machine will be described.

First, the substrate 10 is placed on the stage 55. At this time, the substrate 10 is placed so that the alignment mark 13 is positioned at the forefront in the direction of travel of the substrate 10 by the stage 55 (the direction indicated by the arrow in FIG. 1).

When the conveyance of the substrate 10 by the stage 55 is started, first, the alignment mark 13 formed on the surface of the substrate 10 enters the field of view of the imaging means 53 of each exposure unit 51, and the imaging means 53 takes an image thereof. The collating unit compares and collates the image of the alignment mark 13 photographed by the imaging unit 53 with the reference image stored in the storage unit, and calculates a deviation between the position to be exposed and the actually exposed position. To do. The correcting means corrects the position of the mask 50 (particularly, the position perpendicular to the traveling direction of the substrate 10) and the angle (particularly the angle relative to the traveling direction of the substrate 10) based on the calculation result.

The center line of the alignment mark 13 coincides with the set of source signal lines 15 or black matrix center lines formed in the display region 11 (see FIG. 3). Therefore, when the position and angle of the mask 50 are corrected using the alignment mark 13, the same effect as that obtained by photographing and correcting a set of source signal lines 15 or black matrix formed in the display region 11 is obtained. It is done. The set of source signal lines 15 or the black matrix is used as an alignment pattern to be imaged by the imaging unit when the display area 11 is exposed.

When the alignment mark 13 reaches a position where it can be imaged by the imaging means 53, the display area 11 of the substrate 10 does not reach directly below the mask 50. That is, the exposure is not yet started. Therefore, even if the mask 50 is largely moved by the correction using the alignment mark 13, the exposure on the display area 11 is not affected at all.

As the substrate 10 further advances, the display area 11 of the substrate 10 enters the field of view of the imaging means 53. Then, the imaging unit 53 can photograph the alignment pattern formed in the display area 11, and the position and angle of the mask 50 are corrected based on the alignment pattern. At almost the same time, the display area 11 of the substrate 10 reaches a position where it is exposed. As described above, the position and angle of the mask 50 are corrected by the alignment mark 13 until the substrate 10 reaches this position. Therefore, when this position is reached, the position and angle of the mask 50 do not change significantly. As a result, it is possible to improve the accuracy of the exposure position in the vicinity of the exposure start position with respect to the display area 11, and to prevent the occurrence of exposure unevenness.

Thereafter, while the substrate 10 is being transported, the alignment pattern formed in the display region 11 is imaged, the exposure position shift is calculated by comparing and comparing the captured image and the reference image, and the position of the mask 50 based on the calculation result In addition, the angle correction is continuously performed. As a result, it is possible to expose a predetermined linear portion by carrying the substrate 10 once.

As described above, the exposure method according to the present embodiment corrects the position and angle of the mask 50 using the alignment mark 13 formed in advance outside the display area 11 before the exposure to the display area 11 is started. .

In order to realize such an operation, the alignment mark 13 of the substrate 10 is formed at a position where the imaging means 53 of the exposure unit 51 can take an image when the substrate 10 is placed on the stage 55 and conveyed. The number of alignment marks 13 formed on the substrate 10 is equal to the number of exposure units 51 provided in the exposure machine.

The exposure method according to this embodiment is applied to a step of performing a photo-alignment process. The optical alignment treatment can be applied to liquid crystal display panels in various display modes, and is particularly suitable for a liquid crystal display panel in a twisted nematic vertical alignment (VATN) mode. Hereinafter, a method of manufacturing a VATN mode liquid crystal display panel by the exposure method according to the present embodiment will be described with reference to FIGS. 6-8, the pattern formed in the display area 11 is simplified from the pattern shown in FIG. 3 for convenience of explanation.

FIG. 6 is a diagram schematically showing a photo-alignment process for the array substrate using the exposure method according to the first embodiment. The structure of the picture element applied to this embodiment is not particularly limited. Here, a pixel element 21 is formed in a region surrounded by the source signal line 19 and the gate signal line 17, and a pixel having a general configuration in which driving of the pixel is controlled by a thin film transistor will be described as an example. . For the array substrate, as shown in FIG. 6, two regions are assumed to be formed by being divided into approximately halfway between the source signal lines 19 on both sides (line A in the drawing) in each picture element. Then, each region is irradiated with ultraviolet rays from a direction inclined by a predetermined angle θ with respect to the normal of the surface of the picture element. The direction of the irradiation of ultraviolet rays with respect to each region is such that, when the optical axes of the irradiated ultraviolet rays are projected onto the surface of the picture element, the projected optical axes are parallel to the source signal lines 19 and differ from each other by 180 °. To do.

FIG. 7 is a diagram schematically showing a photo-alignment process for the color filter substrate using the exposure method according to the first embodiment. As shown in FIG. 7, on the color filter substrate, a black matrix 23 is formed in a lattice shape, and a color filter layer is formed in each picture element divided by the lattice. The color filter substrate is formed by being divided into two substantially at the middle (line B in the figure) of the two sides constituting the boundary of the picture element, which is parallel to the gate signal line 17 of the array substrate when bonded to the array substrate. Assume two regions to be used. Then, each region is irradiated with ultraviolet rays from a direction inclined by a predetermined angle θ with respect to the normal of the surface of the picture element. The direction of the irradiation of ultraviolet rays with respect to each region is such that, when the optical axes of the irradiated ultraviolet rays are projected onto the surface of the picture element, the projected optical axes are parallel to the gate signal lines 17 of the array substrate and 180 to each other. ° Different orientation.

FIG. 8 is a diagram schematically showing the orientation direction of the liquid crystal molecules in each pixel for the liquid crystal display panel formed by bonding the array substrate shown in FIG. 6 and the color filter substrate shown in FIG. is there. When the liquid crystal display panel is configured by bonding the substrates subjected to the alignment treatment as described above, the liquid crystal molecules filled between the two substrates are applied to each region of each substrate as shown in FIG. Alignment is performed according to the direction of the alignment treatment, that is, the irradiation direction of ultraviolet rays. As a result, a plurality of domain regions having different orientation directions of liquid crystal molecules are formed in each picture element. The arrows in FIG. 8 indicate the orientation directions of the liquid crystal molecules located at the same distance from both substrate surfaces.

FIG. 9 is a schematic plan view showing the configuration of an array substrate photomask used in the exposure method according to the first embodiment. FIG. 10 is a diagram showing the relationship between the size and position of the photomask of FIG. 9 and the pattern formed on the array substrate. In FIG. 10, for convenience of explanation, the pattern formed in the display area 11 is simplified from the pattern shown in FIG.

As shown in FIG. 9, the array substrate photomask 60 is a substantially rectangular plate-shaped member. A plurality of slit-like translucent portions 61 through which ultraviolet rays can pass are formed in parallel at a predetermined pitch Px. As shown in FIG. 10, the pitch Px is set equal to the pitch of the source signal lines 19 formed on the array substrate. Further, the width (dimension on the short side) Lx of the translucent portion 61 is set to a dimension that is approximately ½ of the pitch of the source signal lines 19.

FIG. 11 is a diagram showing the relationship between the dimensions and positions of the color filter substrate photomask used in the exposure method according to the first embodiment and the pattern formed on the color filter substrate.

The color filter substrate photomask 70 has substantially the same configuration as the array substrate photomask 60 (see FIG. 9). That is, a plurality of slit-like light transmitting portions 71 through which ultraviolet rays can pass are formed in parallel at a predetermined pitch Py. The pitch Py is set to be equal to the pitch of the black matrix 23 formed on the color filter substrate (here, the pitch of the side parallel to the gate signal line 17 of the array substrate when superimposed on the array substrate). The Further, the width (dimension on the short side) Ly of the translucent part 71 is set to a dimension that is about ½ of the pitch of the black matrix 23.

When each substrate is exposed by the above-described exposure method using such masks 60, 70, half of each pixel is exposed by one movement of the substrate. After that, the exposure position is shifted by a half pitch of the translucent part, and the angle of ultraviolet irradiation is changed to expose the remaining half region. As a result, the half of each picture element is oriented in different directions.

Embodiment 2
The present embodiment shows another example of alignment marks arranged in the frame region of the display panel substrate. FIG. 12 is an enlarged schematic plan view showing alignment marks formed on the display panel substrate according to the second embodiment. As shown in FIG. 12, in the present embodiment, a slit-shaped notch (extracted portion) having a width (W) of 15 μm and a length (L) of about 500 μm is provided in the planarly arranged member. The notch is used as an alignment mark. As the member arranged in a planar shape, a metal member formed in the same process as the source signal line is used as long as it is provided at a position 2 mm to 50 mm away from the display area corresponding to the array substrate. In the case of being provided at a position 2 mm to 50 mm away from the display area corresponding to the filter substrate, a light shielding member formed in the same process as the black matrix is used. The center line of the notch is formed at a position that coincides with the center line of the source signal line or black matrix formed in the display area.

Embodiment 3
The present embodiment shows another example of alignment marks arranged in the frame region of the display panel substrate. FIG. 13 is an enlarged schematic plan view showing alignment marks formed on the display panel substrate according to the third embodiment. As shown in FIG. 13, in the present embodiment, the alignment mark has an H-shape, and the left and right directions are respectively provided at the upper end and the lower end of a linear portion having a width (W) of 15 μm and a length (L) of about 500 μm. The straight line portions extending in a straight line are connected at the midpoint so as to form a right angle. If it is provided at a position 2 mm to 50 mm away from the display area corresponding to the array substrate, a metal member formed in the same process as the source signal line is used, and 2 mm to 50 mm from the display area corresponding to the color filter substrate. If it is provided at a distant position, a light shielding member formed in the same process as the black matrix is used. The center line of the alignment mark is formed at a position that coincides with the center line of the source signal line or black matrix formed in the display area. The H-shaped alignment mark is advantageous in that it does not easily cause confusion with other patterns.

Embodiment 4
The present embodiment shows another example of alignment marks arranged in the frame region of the display panel substrate. FIG. 14 is a schematic plan view showing an enlarged alignment mark formed on the display panel substrate according to the fourth embodiment. As shown in FIG. 14, in this embodiment, the alignment mark is a dotted line pattern having a width (W) of 15 μm and a total length (L) of about 500 μm. If it is provided at a position 2 mm to 50 mm away from the display area corresponding to the array substrate, a metal member formed in the same process as the source signal line is used, and 2 mm to 50 mm from the display area corresponding to the color filter substrate. If it is provided at a distant position, a light shielding member formed in the same process as the black matrix is used. The center line of the alignment mark is formed at a position that coincides with the center line of the source signal line or black matrix formed in the display area.

Various modifications may be made to the above-described embodiments without departing from the technical idea of the present invention. For example, a configuration described in a specific embodiment may be changed according to a configuration described in another embodiment. You may replace and you may combine each embodiment.

In each of the embodiments described above, the array substrate is exposed while moving the substrate in the extending direction of the source signal line. However, the array substrate may be exposed while moving in the extending direction of the gate signal line. . In this case, the position where the alignment mark is formed may be changed, and the “gate signal line” and the “source signal line” in the above description may be read.

In each of the above-described embodiments, the step of performing the photo-alignment process is exemplified. However, the display panel substrate and the exposure method using the substrate according to the present invention are applied to the production of a color filter substrate and the production of an array substrate. May be. Even in those cases, the same effect can be obtained by applying the present invention to the arrangement of the alignment marks.

Examples of producing a color filter substrate include exposure for forming a black matrix pattern and exposure for forming a color filter pattern of each color. The color of the color filter is not particularly limited, and may be three colors of red, green, and blue, or may be four colors of red, green, blue, and yellow. In this case, the light irradiation angle (θ) is not particularly limited, and may be 0 °.

In the case of producing an array substrate, for example, exposure for forming a pattern such as a gate signal line, a source signal line, and an insulating film can be mentioned. A resist may be applied on the various thin films that form the pattern and exposed, or if the various thin films that form the pattern are photosensitive materials, direct exposure may be performed. In formation of wiring and the like, it is also possible to form a complicated pattern other than a straight line by repeatedly irradiating light to be exposed in a pulse shape.

In addition, this application claims the priority based on the Paris Convention or the laws and regulations in the country to which transition is based on Japanese Patent Application No. 2010-270563 filed on December 3, 2010. The contents of the application are hereby incorporated by reference in their entirety.

10 Mother glass substrate 11 Display area 13 Alignment mark (rectangular pattern)
15 Source signal line 17 Gate signal line 19 Source signal line 21 Picture element electrode 23 Black matrix 50 Mask 51 Exposure unit 53 Imaging unit 55 Stage 60 Photomask 61 for array substrate Translucent portion 70 Photomask 71 for color filter substrate Translucent portion

Claims (7)

A light source, an exposure unit with a photo-mask及 Beauty imaging apparatus, the exposure apparatus having a stage, the display panel substrate placed on the stage to a substrate exposure method of scanning exposure,
The display panel substrate has a display area in which a plurality of picture elements are arranged, and a frame area adjacent to the display area,
An alignment pattern in the display area, and an alignment mark in the frame area;
The alignment mark is a rectangular pattern extending in parallel with the alignment pattern , and is provided in the same number as the number of the exposure units ,
The center of the alignment mark is at a position 2 mm or more away from the display area,
In the scanning exposure, at least one of the display panel substrate and the photomask is moved, and the display area is irradiated with light emitted from the light source through a light transmitting portion provided in the photomask. Yes,
The substrate exposure method includes:
Before scanning exposure in the display area, the information on the position and orientation of the alignment mark is read by the imaging device,
A substrate exposure method, wherein the position and / or orientation of the photomask is adjusted based on the information while the photomask moves from the frame area to the display area. The substrate exposure method according to claim 1, wherein the center of the alignment mark is located at a position within 50 mm from the display area. The display panel substrate includes a wiring in the frame region,
The substrate exposure method according to claim 1, wherein the alignment mark is disposed in a region between the wiring and the display region. 4. The substrate exposure method according to claim 1, wherein the alignment mark is formed by a light shielding member extending in a row. 5. The substrate exposure method according to claim 1, wherein the alignment mark has a straight line portion of 150 μm or more parallel to the alignment pattern in the display area. The substrate exposure method according to claim 1, wherein the alignment marks are arranged in a dotted line shape. The substrate exposure method according to claim 1, wherein the display panel substrate is a substrate used for a liquid crystal display panel, and includes an alignment film.

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