JP2871162B2 - Liquid crystal display panel manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display panel. More specifically, the present invention relates to an improvement in a method of manufacturing an active matrix type liquid crystal display panel for performing panel sealing with high accuracy and high cleanliness.

[0002]

2. Description of the Related Art In recent years, the development of display devices has been remarkable, and in particular, flat displays have rapidly spread in terms of thinness and light weight. Above all, liquid crystal display devices have low drive voltage and are inexpensive, and therefore are actively introduced into OA equipment fields such as personal computers and word processors.

Recently, a black-and-white liquid crystal display device using a double cell or a retardation film has been developed and used. However, further development of a color liquid crystal display device capable of color display is eagerly demanded in the future, and for that purpose, a panel manufacturing technique with high precision and high cleanliness is required.

FIG. 2 is a diagram showing an example of the structure of a liquid crystal display panel, which is an example of a so-called active matrix type color liquid crystal display panel having a thin film transistor matrix structure. 1A is an exploded perspective view, and FIG. 1B is a cross-sectional view.

On one transparent substrate 1, for example, a black matrix layer 301 made of a chromium (Cr) thin film for preventing light from leaking in a non-pixel portion, and R, G, and B colors divided by the black matrix layer 301 are formed. A filter 300 and a top coat layer 302 are formed, on which, for example, a transparent ITO
Solid common electrode 200a made of (In ₂ O ₃ —SnO ₂ ) film
Further, an alignment film 400 is formed by coating the polyimide resin film thereon and then rubbing it with a rayon brush to perform an alignment process.
A common electrode substrate is configured.

On the other transparent substrate 1, for example, a thin-film transistor array made of amorphous Si (a-Si) is formed in a matrix, and a transparent IT which becomes a pixel electrode 200d is formed on a source electrode of each transistor.
An O film is formed to constitute a pixel portion. A gate bus line and a data bus line connecting the gate electrode and the drain electrode of each thin film transistor are formed in a pattern, and are connected to the gate electrode 200b and the data electrode 200c, which are external connection terminals, respectively. Then, an alignment film 400 is also formed on the pixel portion by rubbing,
A so-called thin film transistor matrix substrate is configured.

[0007] Both substrates face each other with the orientation film 400 facing 5 μm.
A spacer (not shown) is sandwiched so as to form a narrow space of about m, and a sealing agent 2 ′ is applied to the periphery of the substrate and then bonded to form a so-called empty cell. For example, a TN (Twisted Nematic) type liquid crystal is injected and sealed from the injection port 20 'to form an active matrix type liquid crystal display panel.

Reference numeral 201 in the figure denotes a transfer electrode made of, for example, a conductive spacer for electrically connecting the common electrode 200a of the common electrode substrate to the common electrode terminal 202 formed on the thin film transistor matrix substrate side. .

Usually, a screen printing method is often used for forming a seal layer with the sealant 2 ', and there is an advantage that a seal layer can be formed with a uniform width and high accuracy, and is applied to a general monochrome liquid crystal display device. I have. However, this method has a high possibility that various contaminants are transferred onto a substrate from a printing plate of screen printing, and requires formation of a high-density pattern like a liquid crystal display panel of a color display (normal black and white display). If the pattern density is more than 3 times that of
There are drawbacks such as display failure and yield reduction due to such contamination.

Therefore, recently, a method of preventing contamination such as application of a sealant by a dispenser has been studied. FIG. 3 is a view showing an example of a conventional method of applying a sealant, in which a high-cleanliness panel seal is performed using a dispenser.

The transparent substrate 1, for example, a thin film transistor matrix substrate is mounted on a moving stage (not shown), and is configured to apply a sealant 2 'to a peripheral portion of the substrate in a required shape using a dispenser 3. ing.

The dispenser 3 contains a sealant 2 ', for example, an adhesive made of an epoxy resin, and its upper end is covered with a cover 31 hermetically sealed with an O-ring. An air pipe 40 is connected to the cover 31, and compressed air controlled to an appropriate pressure by the control valve 4 is sent to discharge a predetermined amount of the sealant 2 ′ from the needle 30 to a predetermined width and height on the substrate. The seal layer is applied by moving a stage (not shown).

In some cases, the imaging device 10 and the TV
The monitor 11 and the image processing controller 9 monitor the dropping amount of the sealant 2 ′, that is, the width and height of the seal layer, and feed back the data to the control valve 4 to finely adjust the pressure of the compressed air to perform dispenser operation. The amount of the sealant 2 ′ dropped from 3 is controlled.

[0014]

However, in the conventional method of forming a seal using the dispenser 3, the distance between the tip of the needle 30 and the substrate is made constant, or test coating is performed in advance in an empty space on the substrate, that is, the empty space is formed. Even if the application amount is controlled by punching, the width and height of the seal layer vary within the same substrate or between substrates due to variations in the diameter of the needle and changes in the viscosity of the sealant 2 ′ over time, Problems such as poor sealing, difficulty in cutting the edge of the substrate, and poor connection of the wiring terminal portions occur, and a solution is required.

[0015]

The above object is achieved by applying a sealant 2 to at least the peripheral portions of two transparent substrates 1 on which a drive electrode 200 and an alignment film 400 are laminated, and bonding the two substrates together. In a method for manufacturing a liquid crystal display panel in which a liquid crystal 100 is injected and sealed between substrates, a liquid crystal in which the sealant 2 is made of a luminescent sealant and the amount of the sealant 2 applied is controlled by measuring the emission luminance. The problem can be solved by a method for manufacturing a display panel. Specifically, the test application and the main application of the sealant 2 may be performed using the dispenser 3. Further, the sealant 2 may be made of a mixture of a non-light-emitting sealant and a fluorescent substance.

[0016]

According to the method of the present invention, the amount of light emitted from the sealant 2 applied at the time of test application (idling) of the sealant 2 or during the actual application is detected to control the amount of discharge from the dispenser 3. ing. In this case, the amount of light emission is almost proportional to the amount of the applied sealant 2, that is, the volume, so that the amount of application can be controlled extremely accurately and easily, and therefore, with high accuracy. This makes it possible to seal panels with high cleanliness.

[0017]

FIG. 1 shows an embodiment of the present invention. FIG. 1 (a) shows an example of the apparatus configuration, and FIG. 1 (b) shows an example of experimental data.

In the drawing, reference numeral 8 denotes an optical fiber for guiding ultraviolet rays from a mercury lamp (not shown) or the like to collimate the lens 8.
0 is provided to irradiate the blanked or applied sealant 2 through 0.

Reference numeral 5 denotes a light receiving element, for example, a photodiode, and reference numeral 6 denotes an electronic circuit including a lock-in amplifier and the like for performing fine adjustment of the control valve 4 by receiving an electric signal from the light receiving element 5 in a measurement control device. Reference numeral 7 denotes a recorder that records the amount of light emission, for example, luminance.

Reference numerals 81 and 82 denote filters, for example, UV
A cut filter and a green transmission filter. In addition,
The same parts as those described in the above drawings are denoted by the same reference numerals, and the description of the same parts will be omitted.

In FIG. 1A, as the transparent substrate 1, for example, a glass plate having a size of 250.times.400 mm and a thickness of 1.1 mm is used.
A thin film transistor array made of (a-Si) was formed in a matrix, and a transparent ITO film serving as a pixel electrode was formed on a source electrode of each transistor to form a pixel portion.
A gate bus line and a data bus line are formed by connecting the gate electrode and the drain electrode of each thin film transistor,
Each is connected to a gate electrode and a data electrode which are external connection terminals. Then, on the pixel portion, for example, a thin film transistor matrix substrate formed by forming an alignment film obtained by rubbing a polyimide resin film was placed on a moving stage (not shown).

The moving stage is provided with a hole through which light emitted from the applied sealant 2 passes downward. Examples of the sealant 2 include a sealant made of a clear epoxy resin and ZnS: Cu, A which is a green fluorescent substance.
The mixture having a viscosity of about 20,000 CP mixed with 1% by weight of l was put into the dispenser 3 and used. The particle size of the fluorescent substance is 2-4μ
About m is appropriate. If the particle size is too small, the luminous efficiency decreases and the reproducibility deteriorates. On the other hand, if the particle size is too large, it becomes difficult to control the panel gap for enclosing the liquid crystal.

The inner diameter of the tip of the needle 30 of the dispenser 3 is 100 to 200 μmφ. First, before the main coating, that is, the seal coating, a test coating, so-called blank shot, is performed. At that time, the ultraviolet light is irradiated onto the sealant 2 discharged through the optical fiber 8, and the light emitting element 5 and the measurement control device 6 measure the emission luminance. I do.

The predetermined value emission luminance, for example, by controlling the pressure of the compressed air by the control valve 4 so that the B ₀ to adjust the discharge amount of the sealing agent 2 from the needle 30. Then, the emission luminance from the sealing agent 2 discharged again is measured.

When a predetermined discharge amount can always be obtained by repeating this process, the main application, that is, the seal application may be performed. FIG. 2B shows an example of test application data, in which the vertical axis represents luminance and the horizontal axis represents the number of test application times.
Note that the brightness B ₀ is determined by the discharge sealant 2 which can obtain a predetermined discharge amount.
This is the light emission luminance from.

[0026] That is, the test applied (blank beating) is up to 1-3 times in position is varied above and below the predetermined luminance B _0, 4
It can be seen that the target luminance _B0 is stabilized by the fifth to fifth discharge amount adjustments.

When the discharge amount of the sealant 2 is stabilized, the main application, that is, the seal application may be started within 30 seconds.
Even after the start of the main application, if the emission luminance is measured and the luminance is recorded by the recorder 7, the stability of the applied seal layer can be detected, adjusted, and confirmed.

According to this embodiment, for example, the width is 0.5 mm
Can be applied to the seal layer with the design value of ± 10% with an error within ± 10%.
Compared to 50%, a great improvement in accuracy and stability was realized.

In the above embodiment, Zn was used as the fluorescent substance.
S: Cu, Al was used, but not limited to this, Y ₂ O ₃ : E
Other fluorescent substances such as u, ZnS: Ag, ZnS: Mn may be used. In this case, it goes without saying that a color filter corresponding to each emission spectrum is used as the filter 82.

The above-described embodiment is an example.
As long as it complies with the gist of the present invention, it is needless to say that materials and configurations to be used may be suitably used, or a combination thereof may be used.

[0031]

As described above, according to the present invention, the amount of light emitted from the sealant 2 applied at the time of test application (idling) of the sealant 2 or at the time of main application is detected by the dispenser 3 according to the present invention. Is controlled. In this case, the amount of light emission is almost proportional to the amount of the applied sealant 2, that is, the volume, and therefore, the control of the amount of application is extremely accurate.
Moreover, it can be easily performed, and therefore, a panel seal with high accuracy and high cleanliness can be achieved, which greatly contributes to improvement in performance, quality and yield of the liquid crystal display device.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating a structural example of a liquid crystal display panel.

FIG. 3 is a diagram illustrating an example of a conventional sealing agent application method.

[Explanation of symbols]

 1 is a transparent substrate, 2 is a sealant, 3 is a dispenser, 4 is a control valve, 5 is a light receiving element, 6 is a measurement control device, 7 is a recorder, 8 is an optical fiber, 30 is a needle, 31 is a cover, and 32 is O Ring, 40 is air piping, 81, 82 are filters,

Claims (3)

(57) [Claims] 1. A sealant (2) is applied to the periphery of at least two transparent substrates (1) on which a drive electrode (200) and an alignment film (400) are laminated, and the two substrates are bonded to each other. In a method for manufacturing a liquid crystal display panel in which a liquid crystal (100) is injected and sealed therebetween, the sealant (2) is made of a luminescent sealant, and the application amount of the sealant (2) is controlled by the emission luminance. A method for manufacturing a liquid crystal display panel, which is performed by measurement. 2. The method for manufacturing a liquid crystal display panel according to claim 1, wherein the test application and the main application of the sealing agent (2) are performed using a dispenser (3). 3. The sealant according to claim 1, wherein said sealant comprises a mixture of a non-light-emitting sealant and a fluorescent substance.
Or the method for manufacturing a liquid crystal display panel according to 2.