JP2000147447A - Liquid crystal display device and production therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make even small-sized substrates to be correspondable with a double focus microscope at the time of aligning the substrates by arrangingly forming alignment marks for alignment at diagonal positions corresponding with each other of respective substrates respectively. SOLUTION: A driving substrate 1 on which TFTs for controlling pixels are formed is formed to be a quadriangle and on one side of the substrate 1, a wiring pattern part 2 which is to be electrically connected to the driving circuit of the TFTs is provided. Alignment marks 3a, 3b are formed on the driving substrate 1 and respective alignment marks 3a, 3b are arrangingly formed respectively at diagonal positions of the substrate 1. A counter substrate 4 on which color filters and microlenses or the like are formed is also formed to be a quadriangle. The counter substrate 4 constitutes a liquid crystal panel by laminating with the driving substrate 1. Moreover, alignment marks 5a, 5b are arrangingly formed at the diagonal positions in a form in which the marks 5a, 5b are made to correspond to the mark formation positions of the side of the driving substate 1 with each other on the counter substrate 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device in which two substrates are bonded to each other to form a liquid crystal panel, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the spread of electronic equipment with a liquid crystal display device such as a personal computer, a small television, and a liquid crystal projector, demands for higher performance of the liquid crystal display device have been increasing. Improvements have been made to increase the definition and brightness of the display device.

In general, a panel (liquid crystal panel) of a liquid crystal display device includes a thin film transistor (hereinafter, referred to as "TF") for controlling each pixel.
T), a driving substrate on which a storage capacitor and the like are formed, and a counter substrate on which a color filter (in the case of a color liquid crystal panel), a black matrix, and the like are formed. Of these, the drive substrate has a TFT portion and an opening for taking in incident light, but as a result of the TFT portion occupying an area, sufficient light transmittance may not be ensured in some cases. Therefore, a structure is employed in which light is condensed on each pixel by forming a microlens on the opposite substrate corresponding to the opening of each pixel. As a method of forming a microlens, a method of forming a glass substrate using a transparent resin is known.

In such a liquid crystal display device, the above-mentioned drive substrate and counter substrate are attached to each other at the stage of assembling. In this attachment, for example, the relative positions of the corresponding microlenses and pixels are shifted. , The desired luminance cannot be obtained. for that reason,
When bonding substrates, high positioning accuracy is required.

Therefore, conventionally, in FIG.
As shown in (b), alignment marks 52a and 52b are formed on both sides of the drive substrate 51 in advance, and
Correspondingly, alignment marks 54a and 54b are formed on both sides of the opposing substrate 53, and in actual bonding, each mark position is determined in a state where the driving substrate 51 and the opposing substrate 53 are overlapped. While observing from above with a microscope (not shown), the other substrate (for example, the opposing substrate 53) is moved with the stage relative to the one substrate (for example, the driving substrate 51). At this time, the alignment marks 52a, 54a and 52b, 54
b, the drive substrate 51 and the opposing substrate 5
Since the alignment with the substrate 3 is performed, both substrates are bonded together with a sealing material through a predetermined gap (cell gap) in this state. Incidentally, the gap between the substrates is ensured by spacers spread on the driving substrate 51 or the opposing substrate 53 before the substrates are bonded.

[0006]

When the substrates are aligned using a microscope as described above, the alignment marks 52a, 52 provided on both sides of each substrate are required.
In order to simultaneously check 2b and 54a, 54b in one visual field, it is necessary to set the lens magnification low. However, when the magnification of the lens is reduced, it is not possible to confirm a minute displacement of the alignment marks 52a, 54a and 52b, 54b, so that high positioning accuracy cannot be obtained.

On the other hand, when the magnification of the lens is increased in order to obtain high positioning accuracy, the alignment marks 52a, 54a or 52b, 54b on one side are provided in one field of view.
Only b can be stored. Then, the alignment marks 52a, 54a and 52b on both sides,
It is necessary to frequently move the stage until 54b is completely matched and repeat this many times, so that it takes time to align the substrate.

Further, when the driving substrate 51 and the opposing substrate 53 with microlenses are superimposed, the mark position of each substrate in the optical axis direction of the microscope becomes different. When aligned with the alignment marks 52a and 52b on the 51 side, the images of the alignment marks 54a and 54b on the counter substrate 53 side are blurred.

For these reasons, alignment marks 52a, 54a and 52 provided on both sides of each substrate are provided.
b and 54b were simultaneously developed with a high magnification, and a microscope unit capable of confirming both of these mark images in a just-focused state was developed.
Has been put to practical use.

As shown in FIG. 7, the microscope unit includes a pair of left and right double-focus microscopes (hereinafter simply referred to as “microscopes”).
55a and 55b, and each microscope 55a and 55b has a dual focus function, that is, the drive substrate 5
One-side alignment marks 52a, 52b and counter substrate 5
It has a function that can simultaneously focus on the alignment marks 54a and 54b on the third side. CCD cameras 56a, 56b are provided at the upper ends of the microscopes 55a, 55b.
Is mounted, and images (mark images) captured by the CCD cameras 56a and 56b are displayed on a monitor.

When positioning the substrates using the microscope unit having the above configuration, the distance Lr between the optical axes of the left and right microscopes 55a and 55b is determined by adjusting the alignment marks 52a provided on both sides of each substrate. , 52b and 54a, 54b, the distance between the alignment marks 52a, 54a and 5b is adjusted.
Simultaneous observation of 2b and 54b is realized.

However, in the above-described microscope unit, the lens barrel sizes of the left and right microscopes 55a and 55b are enlarged by the addition of the dual focus function.
The minimum adjustment value of the distance Lr between the optical axes a and 55b is strongly restricted by the lens barrel size of each other. Therefore, there is a drawback in that a bifocal microscope cannot cope with a case where the distance La between the alignment marks 52a, 52b and 54a, 54b provided on both sides of each substrate is smaller than the minimum adjustment value of the distance Lr between the optical axes. is there. By the way, at present, 1.
It can only handle liquid crystal panels of 3 inches or more.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and a liquid crystal panel is constructed by bonding two rectangular substrates together.
In a liquid crystal display device in which alignment marks for alignment are formed on each of the two substrates, a configuration is employed in which alignment marks are arranged and formed at diagonal positions corresponding to the respective substrates.

In the liquid crystal display device having the above structure, the alignment marks for positioning are formed at the corresponding diagonal positions of the respective substrates, so that the distance between the alignment marks can be reduced even if the substrates have the same size. Longer than As a result, when positioning the substrates, it is possible to use a bifocal microscope even with a smaller-sized substrate.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram illustrating an embodiment of a liquid crystal display device according to the present invention. First, as shown in FIG. 1A, a drive substrate 1 on which TFTs for controlling each pixel and the like are formed is rectangular. One side (the upper side in the figure) of the driving substrate 1 has a TFT
Is provided with a wiring pattern section 2 which is electrically connected to the driving circuit. Further, two alignment marks 3a and 3b are formed on the drive substrate 1. Each of the alignment marks 3 a and 3 b has, for example, a cross shape, and is arranged and formed at a diagonal position of the drive substrate 1.

On the other hand, as shown in FIG. 1B, the opposing substrate 4 on which a color filter, a micro lens, and the like are formed is also formed in a square shape. The opposing substrate 4 constitutes a liquid crystal panel by being bonded to the driving substrate 1. In the counter substrate 4, alignment marks 5a and 5b are arranged and formed at diagonal positions corresponding to the mark forming positions on the drive substrate 1 side. Each of the alignment marks 5a and 5b has, for example, a shape in which a smaller diameter square is drawn in a square frame and a straight line is drawn from each corner of the smaller diameter square to each side of the larger diameter square. No.

Incidentally, the alignment marks 3a and 3b on the drive substrate 1 side and the alignment marks 5a and 5b on the counter substrate 4 side are used in the respective substrate manufacturing processes.
For example, when constructing various functional units (TFT, microlens, etc.) using a conductive material (metal, etc.) and an insulating material (resin, etc.) on a transparent glass substrate made of non-alkali glass, etc. It is formed simultaneously (in the same process).

The driving substrate 1 and the opposing substrate 4 having the above configuration
When a liquid crystal panel is constructed using
In a state where the substrates 1 and 4 are superimposed on each other, while observing each mark position from above with a microscope (not shown), one substrate (for example, the driving substrate 1) and the other substrate (for example, The opposing substrate 4) is relatively moved. At this time, the alignment marks 3a, 5a and 3
By aligning b and 5b, the driving substrate 1 and the counter substrate 4 are aligned with each other. In this state, both substrates are bonded to each other with a sealing material through a predetermined gap (cell gap). Further, a liquid crystal is filled between the drive substrate 1 and the opposing substrate 4 (cell gap), which have been bonded, by, for example, a vacuum injection method, and the injection port is closed with a sealing material to form one liquid crystal panel. Complete.

In this embodiment, the alignment marks 3a and 3a are positioned at diagonal positions corresponding to the two substrates, that is, the driving substrate 1 and the opposing substrate 4, respectively.
3b, 5a and 5b are arranged and formed, so that the distance Lb between the alignment marks 3a, 3b and 5a and 5b is smaller than that in the conventional case where alignment marks are formed on both sides of each substrate. Mark distance (Fig. 6
Is wider than the distance La).

As a result, when the position of the driving substrate 1 and the position of the opposing substrate 4 are aligned using a bifocal microscope, as shown in FIG. When the microscopes (two bifocal microscopes) are arranged, the positions of the lens barrels (shown by broken lines) in the hatched portions interfere with each other. However, as in the present embodiment, the alignment marks 3a, 3b and 5a,
If 5b is disposed at each diagonal position MPb of each of the substrates 1 and 4, the lens barrel positions (shown by solid lines in the figure) of the two microscopes do not interfere with each other.

As a result, it is possible to cope with even smaller-sized substrates (liquid crystal panels) by using a bifocal microscope.
By the way, as a corresponding size of the bifocal microscope, a liquid crystal panel having a size of 1.3 inches or more has been conventionally supported, but by adopting the present embodiment, a liquid crystal panel having a size of about 0.9 inches can be supported by adopting the present embodiment. It becomes possible.

In the case of a microscope unit having a pair of right and left microscopes (see FIG. 7), the direction in which the distance between the optical axes of the two microscopes (the distance Lr in FIG. 7) is adjusted is orthogonal to the optical axis of the microscope. In addition, it is restricted only in the direction connecting the optical axes (uniaxial direction). On the other hand, when the size (inch size) of the liquid crystal panel changes, the distance Lb (see FIG. 1) between the alignment marks 3a, 3b and 5a, 5b formed at the diagonal positions of the respective substrates correspondingly changes. Change. Therefore, in order to support liquid crystal panels of various sizes with a common microscope unit, the direction of adjusting the distance between the optical axes is determined by changing the line segment connecting the alignment marks 3a, 3b and 5a, 5b, that is, the diagonal line of the substrates 1, 4. Must match direction.

In such a case, for example, if the alignment marks 3a and 3b on the side of the drive substrate 1 are formed in a cruciform shape in accordance with the xy coordinates where the horizontal direction of the substrate is the x direction and the vertical direction is the y direction, the mark image is formed. When captured by a CCD camera or the like and displayed on a monitor, the cross mark
It looks like a cross (x) as shown in FIG. Then, when the operator aligns the substrate while looking at the mark image projected on the monitor, the "x" shape is more difficult to align than the cross shape due to the relationship between the mark angle and visibility. Become. The same can be said for the alignment marks 5a and 5b formed on the counter substrate 4 side.

Therefore, in this embodiment, FIG.
As shown in (a) and (b), the alignment marks 3a and 3b on the drive substrate 1 and the alignment marks 5a and 5b on the counter substrate 4 are formed obliquely along the diagonal line K of each substrate. is there. Specifically, assuming that the horizontal direction of each substrate is the x-axis direction and the diagonal line K of each substrate forms an angle α with respect to the x-axis, the alignment marks 3, 3b and 5a have the same angle α. , 5b are inclined.

Accordingly, even when the direction of adjusting the distance between the optical axes of the microscope unit is made to coincide with the diagonal direction of the substrate as described above, for example, the cross-shaped alignment marks 3a and 3b formed on the driving substrate 1 side can be used. As shown in FIG. 4B, since the image is displayed in a cross shape on the screen of the monitor, the positioning operation can be easily performed while watching the monitor screen, and the work efficiency is improved.

Generally, the positioning of the driving substrate 1 and the opposing substrate 4 is performed by moving the other substrate (eg, the opposing substrate 4) relative to one substrate (eg, the driving substrate 1). The alignment is performed by aligning the alignment marks 3a, 3b and 5a, 5b formed on each of the substrates 1, 4 with the relative movement of the other substrate being x-.
This is performed using a y-θ stage.

At this time, the coordinate system of the liquid crystal panel, that is, the horizontal direction of each substrate (drive substrate 1, counter substrate 4) is defined as the x-axis direction,
Use a coordinate system in which the vertical direction is the y-axis direction (xy-θ
Of the moving direction of the substrate by the stage, the x direction is set to the horizontal direction of the substrate and the y direction is set to the vertical direction of the substrate), and the adjustment direction of the optical axis distance of the microscope unit is set to the diagonal direction of the substrate as described above. If they are matched, the following problems occur. That is, when the operator operates the xy-θ stage adjustment knob or the like to move the stage in the x direction (or y direction), the mark position on the monitor moves diagonally. In addition, a sensible shift occurs between the actual movement of the stage and the movement of the mark on the monitor, thereby deteriorating work efficiency.

Therefore, in this embodiment, an alignment coordinate system as shown in FIG. 5 is adopted. FIG.
In the above, the x direction, the y direction, and the θ direction are the above xy-
The direction of movement of the substrate by the θ stage is shown. In this alignment coordinate system, the x-axis direction, which is one of the directions of movement of the substrate by the xy-θ stage, is made coincident with the diagonal direction of the substrates 1 and 4 passing the alignment mark formation position MP.

More specifically, when, for example, the counter substrate 4 is placed on the xy-θ stage, an alignment mark (mark center) 5 is formed at a diagonal position of the counter substrate 4.
The xy-θ stage is tilted in the θ direction by the diagonal angle α of the substrate (see FIG. 3) so that the axis direction passing through a and 5b substantially matches the x-axis direction of the xy-θ stage. Like that.

By aligning the substrate in such a state, when the substrate (for example, the opposing substrate 4) is moved in the x direction (or y direction) by the xy-θ stage, it is displayed on the monitor. Mark position moves in the horizontal direction (or the vertical direction). As a result, the actual movement of the stage and the movement of the mark on the monitor are intuitively matched, so that the positioning of the substrate is facilitated and the working efficiency is improved.

When positioning the substrate, x-
The same effect as described above can be obtained even when the y-axis direction orthogonal to the x-axis direction of the substrate moving direction by the y-θ stage is made to coincide with the diagonal direction of the substrate.

[0032]

As described above, according to the liquid crystal display device of the present invention, the alignment marks for positioning are formed at the corresponding diagonal positions of the respective substrates. Even with a substrate (panel) of a size, the distance between the alignment marks can be secured longer than before. Thereby, when positioning the substrates, even a smaller-sized substrate can be handled by a bifocal microscope, and particularly, a small liquid crystal display panel can be accurately assembled in a short time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a diagram illustrating a relationship between a mark formation position and a position of a lens barrel of a microscope.

FIG. 3 is a diagram showing a state of inclination of an alignment mark with respect to a substrate.

FIG. 4 is a diagram showing a display state of an alignment mark on a monitor.

FIG. 5 is a diagram illustrating a method for manufacturing a liquid crystal display device according to the present invention.

FIG. 6 is a diagram illustrating a conventional example.

FIG. 7 is a diagram illustrating a configuration of a microscope unit for substrate positioning.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Driving board, 3a, 3b, 5a, 5b ... Alignment mark, 4 ... Counter substrate

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H088 EA03 FA04 FA10 FA16 FA17 FA18 FA30 HA08 HA25 MA03 MA04 2H089 NA09 NA24 NA38 NA53 NA56 NA60 QA11 QA12 TA09 TA12 TA16 5F031 CA05 CA07 JA38 KA06 KA08 5G435 AA17 BB12 KK05 LL05

Claims (3)

[Claims] 1. A liquid crystal display device comprising: a liquid crystal panel formed by adhering two rectangular substrates to each other; and forming alignment marks for alignment on the two substrates, respectively. Are arranged and formed at corresponding diagonal positions of the substrates, respectively. 2. The liquid crystal display device according to claim 1, wherein said alignment mark is formed obliquely along a diagonal line of each of said substrates. 3. When manufacturing the liquid crystal display device according to claim 1, the one of the two substrates is relatively moved with respect to one of the two substrates by an xy-θ stage. A method of positioning the two substrates, wherein, among the moving directions of the other substrate by the xy-θ stage, the x-axis direction or the y-axis direction is substantially in the diagonal direction of the substrate. A method for manufacturing a liquid crystal display device, comprising: positioning a substrate in a state where the substrates are aligned.