TW201346402A - Device for inspecting liquid crystal dispensing state and liquid crystal dispenser having the same - Google Patents

Abstract

Disclosed herein are a device for inspecting a liquid crystal dispensing state of a substrate on which a liquid crystal is dispensed, and a liquid crystal dispenser having the device. The dispensing-state inspecting device includes a light source having a first polarizing plate, and an inspection camera having a second polarizing plate. Light emitted from the light source passes through the first polarizing plate to be radiated to the substrate on which a liquid crystal is dispensed, and light reflected or refracted by the substrate or liquid crystal is incident on the inspection camera through the second polarizing plate.

Description

Device for checking liquid crystal coating state and liquid crystal coating machine having the same

The present invention generally relates to an apparatus for inspecting a liquid crystal coating state and a liquid crystal coater having the same. More specifically, the present invention relates to an apparatus for inspecting a liquid crystal coating state of a substrate coated with a liquid crystal, and a liquid crystal coater having the same.

A liquid crystal display (LCD) is a display that uses the light modulation properties of liquid crystals. In general, an LCD is manufactured by placing a liquid crystal layer between a substrate having a color filter layer and a substrate on which a driving device is disposed, and then bonding the two substrates to each other.

A liquid crystal coater is a device that applies liquid crystal on a substrate in an LCD manufacturing process. The liquid crystal coater is configured to apply liquid crystal on the substrate in the form of droplets or fine particles.

The amount of liquid crystal coated on the substrate by the liquid crystal coater must be controlled as accurately as possible within a preset error range. To this end, Korean Patent No. 964949 proposes a method of precisely controlling the number of liquid crystal droplets. According to the above patent, the number of liquid crystal droplets can be calculated in a fairly reliable manner.

Meanwhile, the inventors of the present invention found that it is necessary to inspect the liquid crystal coating state of the substrate. This is a condition in which it is necessary to detect that the liquid crystal is not precisely coated, for example, a condition in which some liquid crystal droplets are not normally discharged during the liquid crystal coating process, or a state in which the liquid crystal is not coated according to a predetermined liquid crystal coating pattern.

Accordingly, the present invention has been made in view of the problems occurring in the prior art, and an object of the present invention is to provide an apparatus for inspecting a liquid crystal coating state by obtaining an image of a substrate coated with a liquid crystal.

Another object of the present invention is to provide a liquid crystal coater having means for inspecting a liquid crystal coating state.

In order to achieve the above object, the present invention provides an apparatus for inspecting a liquid crystal coating state, comprising: a light source for emitting light, a first polarizing plate, being provided between the light source and the substrate, and the liquid crystal system being coated on the substrate, first The polarizing plate selectively passes the light emitted from the light source through the second polarizing plate, selectively passes the light reflected or refracted by the substrate or the liquid crystal after passing through the first polarizing plate, and inspects the camera, and receives the passed The light of the two polarizers converts the light into electrical signals.

The coating state inspection device according to the present invention may further include: a main frame, a pallet, a predetermined position at an upper portion of the main frame to support the substrate, and a support frame provided at a predetermined position on the upper portion of the main frame, wherein the light source and the inspection camera Installed to the support frame.

According to an embodiment, the coating state inspection device may further include a rotation device for adjusting a polarization direction of the first polarizing plate or the second polarizing plate provided on the inspection camera.

The apparatus may further include a control unit that analyzes an image obtained from the inspection camera and controls a rotation angle of the first polarizing plate or the second polarizing plate by the rotating device.

Furthermore, the polarization direction of the first polarizing plate provided on the light source may be parallel to the rubbing direction processed on the substrate.

According to an embodiment, the light source may be provided laterally along the support frame, and the inspection camera may be a line scan camera or an area scan camera.

In order to achieve the above object, the present invention provides a liquid crystal coating machine for coating liquid crystal to a substrate, comprising: a main frame and a pallet, which are provided at predetermined positions on the upper portion of the main frame to support the substrate and the support frame, and are provided in a predetermined position of the upper part of the main frame, the coating head unit is provided at a predetermined position of the supporting frame to apply the liquid crystal and the light source, and is provided at a predetermined position of the supporting frame, wherein the first polarizing plate is provided on the light output port of the light source, And the inspection camera is provided at a predetermined position of the support frame, wherein the second polarizing plate is provided on the light incident surface thereof.

According to an embodiment, the coating head unit and the inspection camera may be provided on both sides of the support frame.

Further, a liquid crystal coater can be provided on the support frame. The support frame may include an external force device to apply an external force to the liquid crystal coated on the substrate. The external force device may include any of an ultrasonic generator, an ionizer, a plasma generator, and an electric field generator.

Further, if the state of the liquid crystal coated on the substrate is considered to be defective based on the result of analyzing the image obtained from the inspection camera, a control operation can be performed to additionally coat the liquid crystal by the coating head unit.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the same or similar elements in the different drawings will have the same reference numerals. Furthermore, in order to enhance the clarity of the description, the familiar functions and architectures related to the present invention will be omitted. Furthermore, the preferred embodiments of the present invention are described below, but those skilled in the art should understand that the technical concept of the present invention is not limited to the preferred embodiments, and various other forms are possible.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view showing an apparatus for inspecting a liquid crystal coating state according to a preferred embodiment of the present invention, and Fig. 2 is a schematic view showing an apparatus for inspecting a liquid crystal coating state according to a preferred embodiment of the present invention.

The apparatus 1 for inspecting a liquid crystal coating state according to a preferred embodiment of the present invention includes a light source 20 having a first polarizing plate 22 and an inspection camera 30 having a second polarizing plate 32. The coating state inspection apparatus 1 may include a support frame 16 on which the light source 20 and the inspection camera 30 are mounted, a pallet 14 that supports the substrate 12, and a main frame 10 on which the support frame 16 and the pallet 14 are attached. The support frame 16 can be configured to move linearly relative to the substrate 12. To this end, a support frame drive unit 18 can be provided. According to an embodiment, the support frame drive unit 18 can be a linear motor. Reference numeral 13 of Fig. 2 denotes a liquid crystal 13 coated on a substrate 12. Furthermore, the coating state inspection apparatus 1 according to the preferred embodiment of the present invention may include a control unit 40 that processes images obtained from the inspection camera 30 and includes a display unit 42 that outputs the resulting image.

The light source 20 emits light such as blue light, red light, or visible light. According to an embodiment, the light source 20 is disposed across the substrate 12 along the length of the support frame 16. The light emitted from the light source 20 is incident on the substrate 12 in the horizontal direction (assuming that the moving direction of the support frame 16 is the vertical direction). Light output cooker for light source 20 There is a first polarizing plate 22. The first polarizing plate 22 deflects the light emitted from the light source 20 in a specific direction, and only the light polarized by the first polarizing plate 22 illuminates the substrate 12. Here, the irradiation direction of the light source 20 can be set as an area in which the inspection camera 30 acquires an image.

The inspection camera 30 acquires an image of the substrate 12. According to an embodiment, the inspection camera 30 can be an area scan camera or a line scan camera. The area scan camera can only scan and transmit one frame at a time. The area scan camera uses an image sensor with a plurality of horizontal pixels and a plurality of vertical pixels. The line scan camera uses an image sensor with only a single column of horizontal pixels, thus taking an image of the line. In the case of using the area scanning camera or the line scanning camera as the inspection camera 30, the image obtained by the inspection camera 30 must be an image obtained by capturing the light emitted from the light source 20 to the area of the substrate 12.

The second polarizing plate 32 is provided on the front end of the inspection camera 30. Therefore, the inspection camera 30 recognizes only light polarized in the specific direction.

According to an embodiment, the control unit 40 outputs the image obtained by the inspection camera 30 to the display unit 42. Furthermore, the control unit 40 functions to analyze the image obtained from the inspection camera 30, and thus determines whether or not the liquid crystal is normally applied. An example of determining whether a liquid crystal is normally applied includes calculating the amount or configuration of the actual applied liquid crystal and comparing it to the amount or configuration of the normally coated liquid crystal.

Such a control unit 40 can perform at least one of the following functions based on the image obtained from the inspection camera 30: a function of calculating the amount of liquid crystal coated on the substrate 12, and performing a preset liquid crystal coating pattern with the actually applied liquid crystal pattern. Compare functions, calculate the number of coated liquid crystals, and calculate the function of the total amount of liquid crystal (weight of unit liquid crystal x number of coated liquid crystals) coated on the substrate or compare the size of the coated liquid crystal with the size of the liquid crystal coated in a normal state. Therefore, it is judged whether or not the liquid crystal to be coated is appropriate.

3A and 3B are configuration diagrams showing a polarizing plate in an apparatus for inspecting a liquid crystal coating state according to a preferred embodiment of the present invention.

As shown in FIG. 3A, the first polarizing plate 22 and the second polarizing plate 32 may be disposed such that their polarization directions are identical to each other. Alternatively, the first polarizing plate 22 and the second polarizing plate 32 may be configured such that their polarization directions are perpendicular to each other as shown in FIG. 3B. However, according to an embodiment of the present invention, the angle between the polarization direction of the first polarizing plate 22 and the polarization direction of the second polarizing plate 32 is not limited to the angle shown in FIG. 3A or FIG. 3B, but may be improved. The image quality of the liquid crystal applied to the substrate 12 can be adjusted in the range of 0° to 90°.

In the present invention, the reason why the first polarizing plate 22 is provided on the light output port of the light source 20 and the second polarizing plate 32 is provided on the front end of the inspection camera 30 is as follows: the state of the liquid crystal is a state of matter having a property between liquid and crystal, Also known as quasicrystal or anisotropic liquid. When the liquid crystal is a liquid, it has the optical properties of a crystal. If an electric field is applied to the liquid crystal, the directivity of the molecular arrangement is changed. The LCD displays an image by controlling the transmittance of light when the liquid crystal molecules are aligned in the same direction when a voltage is applied to the liquid crystal molecules.

The most commonly used in LCD is nematic liquid crystal (nematic liquid) Crystal). In the nematic liquid crystal, the strip liquid crystal molecules are almost aligned in a uniform direction, and there is no laminated structure. Most of the liquid crystal molecules have a hard strip shape. Liquid crystals have optically anisotropic properties that have different refractive indices in directions parallel to the molecular axis and in the direction perpendicular. These properties cause the polarized light to change the direction of the polarization when passing through the liquid crystal. In the LCD, an electric field is applied to the liquid crystal to configure the liquid crystal in a desired form, thereby controlling the penetration of light.

In the example in which the liquid crystal is coated on the substrate 12, the liquid crystal is configured to have a certain degree of directivity even when an electric field is not applied. For example, when liquid crystal is applied to the substrate 12 that has been subjected to the rubbing process, it is highly likely that the orientation of the liquid crystal coincides with the rubbing direction. When the liquid crystal coating state of the substrate 12 that has passed through the rubbing process is inspected, the polarization direction of the first polarizing plate 22 can be set to correspond to the rubbing direction of the substrate 12. This is because the orientation of the liquid crystal is likely to coincide with the rubbing direction.

A case in which light emitted from the light source 20 is polarized by the first polarizing plate 22 and then irradiated to the substrate 12 will be considered. If water droplets, rather than liquid crystals, drips on the substrate 12, the light polarized by the first polarizing plate 22 is refracted and reflected by the water droplets, but does not change the direction of the polarization. However, if the liquid crystal falls on the substrate 12, the light polarized by the first polarizing plate 22 changes the direction of the polarization due to the liquid crystal, and the light whose direction of the polarization changes is incident on the inspection camera 30. Here, the direction of the polarization which is changed by the liquid crystal can have many various directions.

When the first polarizing plate 22 and the second polarizing plate 32 have the polarization direction as shown in FIG. 3A, the light reflected by the substrate 12 is incident on the inspection camera 30 in such a manner that the polarization direction of the light does not change. Therefore, the image of the area of the substrate 12 captured by the inspection camera 30 will be bright. In contrast, the light reflected or refracted by the liquid crystal enters in such a way that the polarization direction of the light changes. The camera 30 is fired such that some of the light does not pass through the second polarizer 32. Therefore, the portion having the liquid crystal may be darker than the region of the substrate 12. Meanwhile, when the first polarizing plate 22 and the second polarizing plate 32 have the polarization direction as shown in FIG. 3B, the light reflected by the substrate 12 is incident on the inspection camera 30 in such a manner that the polarization direction does not change. Therefore, the light is blocked by the second polarizing plate 32, so that the image of the area of the substrate 12 captured by the inspection camera 30 may be dark. In contrast, the light reflected or refracted by the liquid crystal is incident on the inspection camera 30 in such a manner that the direction of the polarization is changed. Therefore, some of the light passes through the second polarizing plate 32, causing the portion having the liquid crystal to be brighter than the area of the substrate 12. This principle enables the inspection camera 30 to more clearly identify the liquid crystal 13 applied to the substrate 12.

Fig. 4 is a view showing an example of an image captured by an inspection camera of a device for inspecting a liquid crystal coating state according to a preferred embodiment of the present invention.

In FIG. 4, the polarization directions of the first polarizing plate 22 and the second polarizing plate 32 are in the direction of FIG. 3A, and the area scanning camera is used as the inspection camera 30. The area of the substrate 12 is displayed in a bright area in the image captured by the camera 30, and the liquid crystal 13 is displayed in a dark area. Therefore, even if the image is not additionally processed, the liquid crystal coating state can be clearly obtained.

Fig. 5 is a block diagram showing the configuration of a polarizing plate for controlling an image obtaining device in an apparatus for inspecting a liquid crystal coating state according to a preferred embodiment of the present invention.

When the image of the liquid crystal 13 applied to the substrate 12 is obtained, the molecules in the liquid crystal 13 can be in various orientations depending on the situation. Therefore, in order to obtain a clear image, it is necessary to adjust the polarization directions of the first polarizing plate 22 and the second polarizing plate 32. The first polarizing plate 22 is provided on the light output of the light source 20, and thus The first polarizing plate 22 can be easily adjusted. At the same time, the second polarizing plate 32 is attached to the front end of the inspection camera 30, so that the polarization direction can be easily adjusted by manually or automatically rotating the second polarizing plate 32. According to an embodiment of the present invention, the first polarizing plate 22 may be rotatable instead of the second polarizing plate 32, or both the first polarizing plate 22 and the second polarizing plate 32 may be naturally rotated.

In FIG. 5, a rotating device 44 is provided to rotate the second polarizing plate 32, and the control unit 40 controls the rotation of the rotating device 44. In the example of the rotating device 44, the rotating device 44 can be configured to include a motor (not shown) and a driving gear coupled to the motor, and the gear teeth are formed on the outer circumference of the second polarizing plate 32 to rotate the second polarizing plate by the motor. 32. The control unit 40 drives the rotating device 44 to rotate the second polarizing plate 32, thereby acquiring an image from the inspection camera 30. The control unit 40 analyzes the resulting image and sets the angle of the second polarizing plate 32 to provide a clear contrast between the liquid crystal portion and the substrate portion. In the image analysis example executed by the control unit 40, histogram analysis of the image can be performed. If the image contrast is high, it means that the substrate portion and the liquid crystal portion of the image have a clear contrast with each other. In this case, the histogram of the image is distributed over a wide area.

Figure 6 is a perspective view showing an apparatus for inspecting a liquid crystal coating state according to another preferred embodiment of the present invention.

The general configuration of the apparatus 1 for inspecting the liquid crystal coating state of Fig. 6 remains the same as that of Fig. 1. However, unlike the apparatus of FIG. 1, the apparatus 1 of FIG. 6 has a plurality of inspection cameras 30. In Figure 6, inspection camera 30 can be an area scan camera. The plurality of area scanning cameras capture individual areas divided by the wide substrate 12.

Figure 7 is a perspective view showing a liquid crystal coater having a device for inspecting a liquid crystal coating state in accordance with a preferred embodiment of the present invention.

The liquid crystal coater 100 includes a main frame 10 and a pallet 14 which are attached to the upper surface of the main frame 10 to support the substrate 12 and the support frame 16, and are movably mounted to the main frame 10 and the coating head unit 50. The support frame 16 is movably coupled and coated with liquid crystal to the substrate 12 via individual nozzles as it moves relative to the substrate 12. The liquid crystal coater 100 also includes a light source 20 having a first polarizing plate 22 and an inspection camera 30 having a second polarizing plate 32. The light source 20 and the inspection camera 30 are mounted on the support frame 16.

Referring to FIG. 7, the coating head unit 50 is provided on one surface of the support frame 16, and the light source 20 and the inspection camera 30 are provided on the other surface of the support frame 16. With this configuration, when the liquid crystal is discharged from the coating head unit 50 and applied to the substrate 12 while the support frame 16 is moved, the inspection camera 30 can obtain an image of the substrate 12 coated with the liquid crystal. According to the situation, after all the liquid crystals are applied onto the substrate 12, the image of the entire substrate 12 can be obtained when the support frame 16 is driven, so that the liquid crystal coating state can be inspected.

According to an embodiment of the present invention, if the liquid crystal coating is found to be defective based on the image obtained by the inspection camera 30, a control operation can be performed to move the support frame 16 to a desired area, and the liquid crystal is additionally discharged by the coating head unit 50.

The functions of the above control unit 40 related to the control of the coating head unit 50 will be further explained below.

According to the present invention, a clearer and more clear liquid crystal coating state can be obtained. Image.

The control unit 40 compares the liquid crystal preset coordinate value of the substrate with the state in which the liquid crystal is actually applied to the substrate, thereby judging whether the position or pattern of the applied liquid crystal is appropriate, or whether there is a portion where the liquid crystal coating is missing.

The control unit 40 can calculate the amount of liquid crystal applied on the substrate using the number of liquid crystals applied and the area to which the liquid crystal is applied. Thereby, the control unit 40 determines whether the actually applied amount of liquid crystal does not reach or exceed the total amount of liquid crystal to be applied per unit panel.

The control unit 40 can calculate the area of each of the coated liquid crystals based on the obtained image to determine whether the size of each liquid crystal droplet is appropriate.

Furthermore, after comprehensively checking the above conditions, the control unit 40 can determine whether the actually applied liquid crystal pattern or liquid crystal amount is within the error tolerance range.

When the control unit 40 determines that the liquid crystal coating state is not good, the coating head unit 50 is controlled to additionally coat the liquid crystal to a specific neglected position or additionally coat the liquid crystal, thereby supplementing the missing liquid crystal amount.

Figure 8 is a side view showing a liquid crystal coater having a device for inspecting a liquid crystal coating state according to another preferred embodiment of the present invention.

Referring to FIG. 8, the liquid crystal coater 100 further includes an external force device 60 to apply an external force to the liquid crystal 13 applied to the substrate 12. According to an embodiment, the external force device 60 is provided at the lower end of the support frame 16, but may be positioned at the rear end of the coating head unit 50. The external force device 60 applies an external force to the liquid crystal to make the liquid crystal The molecules in the configuration are in a specific direction. When the light emitted by the light source 20 is irradiated through the first polarizing plate 22 to the substrate 12, and the light reflected or refracted by the substrate 12 and the liquid crystal is irradiated to the inspection camera 30 through the second polarizing plate 32, this is used to provide a clear image of the liquid crystal. . An ultrasonic generator, an ionizer, a plasma generator or an electric field generator can be used as the external force device 60. If an external force is applied to the applied liquid crystal to make the molecular arrangement of the liquid crystal more regular, the image input to the inspection camera 30 can be made clearer.

As described above, the present invention can provide a clear image of the liquid crystal state coated on the substrate. Furthermore, the present invention can clearly understand the liquid crystal coating state based on the liquid crystal image applied to the substrate without additional image processing or with minimal image processing.

Furthermore, the present invention can make the liquid crystal portion of the image clearer by adjusting the polarization direction of the polarizing plate. According to the present invention, the liquid crystal portion of the image can be made sharper by adjusting the orientation of the liquid crystal by adjusting the external force applied to the liquid crystal.

Furthermore, the present invention integrates the apparatus for inspecting the liquid crystal coating state into the liquid crystal coater so that the liquid crystal coating state can be easily checked immediately after the liquid crystal is applied or after the liquid crystal is applied. Further, if the liquid crystal coating state is defective, a control operation is performed to additionally coat the liquid crystal, thereby solving the problem caused by the defective liquid crystal coating state.

While the invention has been described with respect to the preferred embodiments of the present invention, it is understood that various modifications, additions and substitutions may be made without departing from the scope and spirit of the invention. Therefore, the embodiments and accompanying drawings disclosed herein are not limiting but illustrative, and The technical scope of the present invention is not limited to these embodiments and accompanying drawings. The scope of the invention should be construed as the scope of the claims, and all technical concepts of the scope of the claims are intended to fall within the scope of the invention.

1‧‧‧Device for checking the state of liquid crystal coating

10‧‧‧ main frame

12‧‧‧Support substrate

13‧‧‧LCD

14‧‧‧托台

16‧‧‧Support frame

18‧‧‧Support frame drive unit

20‧‧‧Light source

22‧‧‧First polarizer

30‧‧‧Check camera

32‧‧‧Second polarizer

40‧‧‧Control unit

42‧‧‧Display unit

44‧‧‧Rotating device

50‧‧‧ Coating head unit

60‧‧‧External force device

100‧‧‧LCD coating machine

The above and other objects, features, and advantages of the present invention will become more <RTIgt; FIG. 3A and FIG. 3B are diagrams showing a configuration of a polarizing plate in a device for inspecting a liquid crystal coating state according to a preferred embodiment of the present invention; FIG. 4 is a view showing a device for inspecting a liquid crystal coating state according to a preferred embodiment of the present invention; FIG. 5 is a view showing an image captured by an inspection camera of a device for inspecting a liquid crystal coating state according to a preferred embodiment of the present invention; FIG. 5 is a view showing a device for controlling an image capturing device in a device for inspecting a liquid crystal coating state according to a preferred embodiment of the present invention; FIG. 6 is a perspective view showing a device for inspecting a liquid crystal coating state according to another preferred embodiment of the present invention; FIG. 7 is a view showing a device for inspecting a liquid crystal coating state according to a preferred embodiment of the present invention; A perspective view of a liquid crystal coater; and Fig. 8 is a side view showing a liquid crystal coater having a device for inspecting a liquid crystal coating state according to another preferred embodiment of the present invention.

12‧‧‧Support substrate

13‧‧‧LCD

20‧‧‧Light source

22‧‧‧First polarizer

30‧‧‧Check camera

32‧‧‧Second polarizer

40‧‧‧Control unit

42‧‧‧Display unit

Claims (11)

The device for inspecting a liquid crystal coating state comprises: a light source emitting light; a first polarizing plate provided between the light source and a substrate, a liquid crystal coated on the substrate, the first polarizing plate being selectively Passing light emitted by the light source; a second polarizing plate selectively passing light reflected or refracted by the substrate or the liquid crystal through the first polarizing plate; and an inspection camera, the receiving has passed the first The light of the two polarizers converts the light into an electrical signal. The device of claim 1, further comprising: a rotating device for adjusting a polarization direction of the first polarizing plate or the second polarizing plate. The device of claim 2, further comprising: a control unit that analyzes an image obtained from the inspection camera, and controls a rotation of the first polarizing plate or the second polarizing plate by the rotating device angle. The device of claim 1, wherein the polarization direction of the first polarizing plate provided on the light source is parallel to a rubbing direction of the substrate processing. The device of claim 1, wherein the inspection camera is a line scan camera or an area scan camera. For example, the device described in claim 1 further includes: A control unit determines whether the coating of the liquid crystal is appropriate based on the image obtained from the inspection camera. A liquid crystal coating machine for coating a liquid crystal to a substrate, comprising: a main frame; a tray provided on an upper portion of the main frame to support the substrate; and a support frame provided on the main frame The upper portion; a coating head unit is provided on the support frame to coat the liquid crystal; a light source is provided on the support frame, wherein a first polarizing plate is provided on one of the light output ports of the light source; and an inspection A camera is provided on the support frame, wherein a second polarizer is provided on a light incident surface thereof. The liquid crystal coater of claim 7, wherein the coating head unit and the inspection camera are provided on both sides of the support frame. The liquid crystal coater of claim 7, wherein the support frame comprises an external force device for applying an external force to the liquid crystal coated on the substrate. The liquid crystal coating machine of claim 9, wherein the external force device comprises any one of an ultrasonic generator, an ionizer, a plasma generator, and an electric field generator. The liquid crystal coating machine according to any one of claims 7 to 10, wherein if the state of the liquid crystal coated on the substrate is considered to be defective based on a result of analyzing an image obtained from the inspection camera, A control operation is then performed to additionally coat the liquid crystal by the coating head unit.