The present invention relates to a coating device and method, and in particular to a micro patch coating device which can be applied in the fabrication of color filters of flat panel liquid crystal displays (LCD) and coloring unit of the fluorescent film in plasma display modules, or in the manufacturing of biomedical products and flexible electronics and cells.
With the development of information technology, flat panel display has gradually replaced the conventional cathode ray tubes (CRT) display. Flat panel LCD, for instance, which takes up the largest market share among all flat panel displays, is composed of backlight source, light polarizer, glass substrate, liquid crystal, thin film transistor (TFT), color filter (CF), etc., while the color filter is the key component determining the color characteristics and contrast of a LCD.
Color filters in LCD and coloring unit for the fluorescent film in plasma display panel modules are the key components of the structures that convert black and white flat panel display into colorful ones. The coating structures of color filter for flat panel LCD, for instance, comprises a plurality of pixels of red (R), green (G) and blue (B) colors which are arranged in arrays on glass substrate, while a couple of pixels (normally three) correspond to one color dot on the display. When white light passes through the trichromatic pixels, it generates three primary colors of light, namely the red, green and blue light, which, by means of gray scale effect generated by the liquid crystal molecules, are further blended and form various colors.
The technologies for the fabrication of color filters can be classified into three types. The first coating type is photolithography method, which is the most frequently used technology currently. In the technology, uniform liquid films are coated to the substrate and defined patterns by photolithography method sequentially. This technology is applied to many methods including dyeing method, pigment dispersing method, electro-deposition, etc. Another type of technology is stamping, in which the patterns are respectively decided by stamps and impressed onto the substrate. The third type of technology is ink injection, in which miniscule droplets of ink are injected onto a substrate by ink injecting heads, allowing direct formation of micro patch patterns.
Referring to photolithography technology mentioned above, the prerequisite is to coat a liquid film uniformly. Currently, the most frequently used coating method is spin coating (as disclosed in
The conventional dyeing method (as disclosed in
Conventional pigment dispersing method (as disclosed in
Known electro-deposition (as disclosed in
To conclude, the conventional coating technology fails to define patterns directly at coating, and it relies, instead, on exposure to remove excessive materials. Thus, it results in low material utility rate throughout the whole process, e.g. less than one third of the material, failing to satisfy the needs for mass production and at low costs.
A manufacturing method using stamping is disclosed in Taiwan Patent No.
An ink injection method is taught in Taiwan Patent No.
However, since the ink injection method basically forms a line or surface pattern by a numerous dots, each droplet must be injected with extremely high accuracy into a block of a few microns or even smaller dimension. Besides, the traveling paths of droplets are susceptible to air flow disturbance, and it is likely that the ink droplets are injected accidentally to adjacent blocks and results in contamination. Therefore, a high precision machine is required. Also, the moving rate of the ink injecting head module is limited to secure precise injection. This can be what holds up the application of the method in industry. Because each of ink injecting heads is allowed to jet only one droplet at one time, the production efficiency is very low. In order to solve this problem, the numbers of the ink injecting heads have to be increased (which inevitably increase the cost). Besides, when ink injections are taking place in parallel movements, all ink injecting heads have to be in good condition without any clogging or abnormal situation. When the ink injection method is applied in large sized display panels, an enlarged dimension of machine is used. It should be careful to maintain good machine mobility and coating uniformity. These problems are yet to be solved in the future when large dimension TV displays will become the major products.
Thus, it is desired to develop a coating method that is simple in operation, has good yield rate and is economical for application.
A primary object of the present invention is to provide a micro patch coating device to overcome the drawbacks of above-mentioned conventional methods. In the present invention, at least one coating fluid and at least one auxiliary fluid are conveyed into a coating die comprising a micro channel structure, generating a two-phase fluid having alternate arrangement of the coating fluid and the auxiliary fluid. The coating die is driven to move along a direction in parallel to a substrate and injects the two-phase fluid directly on the substrate at predetermined locations and forms micro patches.
Another object of the present invention is to provide a slit coating method for generating discontinuous pattern. The coating method comprises a fluid generator which alternatively intercepts the supply of a coating fluid and that of an auxiliary fluid. By moving the coating die or the substrate and coating the two-phase fluid on the substrate, micro patches are formed on the substrate.
To fulfill the above objects, the present invention provides a device according to claims 9 to 17 and a method for micro patch coating according to claims 1 to 8. The micro patch coating device comprises a coating die with a micro channel structure. A coating fluid is supplied through a coating fluid inlet and an auxiliary fluid is supplied through an auxiliary fluid inlet. After a segment of a predetermined length of the coating fluid is formed at a two-phase fluid output section, the coating fluid flow is intercepted. In turn, a segment of predetermined length of the auxiliary fluid is formed at the two-phase fluid output section, and then the auxiliary fluid flow is intercepted. A two-phase fluid is formed and flows out of the coating die to the substrate to form micro patches thereon.
The coating method in the present invention overcomes the low material utility rate problem happened in spin coating and photolithography, and is applicable in coating larger dimension display panels. The present invention also solves the problems of low yield rate and low production efficiency in ink injection method, and it allows high degree of variation of the pattern which cannot be achieved by stamping. The method of the present invention lowers the manufacturing costs, improves the production efficiency, and is capable to be used for producing larger dimension display panels and sophisticated micro patch patterns for matching the future development.
Furthermore, the present invention provides higher material utility rate than that of photolithography that requires repeated exposure procedures. The present invention saves the processing time. In the coating method of the present invention, coating patterns are formed by varying the output ratio of the coating and auxiliary fluid and the relative movements between the coating die and the substrate. Besides, by directly coating the two-phase fluid to the substrate, the pattern is easily changed than that produced by stamping. Meanwhile, the method does not require of high precision injection as that as required in conventional ink injecting and enables higher yield rate in production.
The present invention will be apparent to those skilled in the art by reading the following description of embodiment thereof, with reference to the attached drawings, in which:
With reference to the drawings and in particular to
The micro channel 12 is supported by the supporting member 14 coupled to the driving mechanism 13. The supporting member 14 is driven to displace along a horizontal direction I back and forth by the driving mechanism 13. In this embodiment, the micro channel 12 may be a capillary tube.
The micro channel 12 has an inlet 121 and an outlet 122. The outlet 122 of the micro channel 12 is kept at a predetermined distance from the top surface of a substrate 6. The inlet 121 of the micro channel 12 is connected to the fluid driving mechanism 16 composed of a syringe 161, a plunger 162, and a pump 163. The connector 15 is connected between the inlet 121 of the micro channel 12 and the syringe 161.
The syringe 161 comprises a plunger 162 which is connected to the pump 163. The pump 163 is controlled by a control device (not shown) to push the plunger 162 forward or pull the plunger 162 backward along a direction II parallel to the lengthwise direction of the syringe 161. When the pump 163 pushes the plunger 162 forward, the two-phase fluid 11 contained in the micro channel 12 is driven to flow out to the outlet 122 of the micro channel 12.
Meanwhile, the driving mechanism 13 drives the micro channel 12 via the supporting member 14 to displace along the horizontal direction I in parallel to the surface of the substrate 6.
Please refer to
As it can be seen from the drawings, when the driving mechanism 13 moves the micro channel 12 to displace horizontally and the fluid driving mechanism 16 pushes the two-phase fluid 11 in the micro channel 12, the two-phase fluid 11 flows out from the outlet 122 of the micro channel 12, thereby forming a fluid film 7' on the substrate 6.
After flowing out of the outlet 122, the two-phase fluid 11 is coated at predetermined locations of the substrate 6 and thereby a micro-patch pattern comprising a number of micro patches 7a is formed on the substrate 6.
In the case a gas is used as the auxiliary fluid 3, micro patches 7a are directly formed on the substrate 6. In the case a liquid that is immiscible with the coating fluid 2a is used as the auxiliary fluid 3, the substrate 6 could be heated to vaporize the auxiliary fluid 3 by baking, leaving the coating fluid 2a to form the micro patches 7a. The flowing velocity of the two-phase fluid 11 is determined by the pumping rate of the pump 163 which is controlled through the control device.
The coating fluid 2a has a surface tension at the through hole 181 that prevents the leakage of the coating fluid 2a from the coating fluid supply tank 18, even though no stopper or sealing is provided at the through hole 181.
For obtaining the two-phase fluid 11, the driving mechanism 13 drives the micro channel 12 to displace along the horizontal direction I, and the micro channel 12 penetrates through the through hole 181 to the coating fluid supply tank 18, as shown in
Please refer to
In the first embodiment, the auxiliary fluid is a gas. In application, the auxiliary fluid 3 may comprise a liquid immiscible with the coating fluid 2a. An auxiliary fluid supply tank (not shown) is provided for supplying the auxiliary fluid.
The two-phase fluid generating device in
The first embodiment of the micro patch coating device described above is provided with only one micro channel therein. In application, a number of micro channels may be installed in the micro patch coating device for forming a number of parallel micro patches spaced from each other with a predetermined distance on the substrate at the same time. For example,
With reference to
As shown in
The micro channel structure 4 comprises a plurality of coating fluid buffering sections 211, 212, 213, a plurality of coating fluid passages 21a', 21b', 21c', a plurality of auxiliary fluid passages 22a, 22b, 22c and a plurality of two-phase fluid output sections 23a, 23b, 23c.
Each of the coating fluid buffering sections 211, 212, 213 is connected to a coating fluid inlet 21a, 21b, 21c. The coating fluid buffering sections 211, 212 and 213 are arranged between the coating fluid inlets 21a, 21b, 21c and the coating fluid passages 21a', 21b', 21c'. The coating fluids 2a, 2b, 2c are respectively supplied from the coating fluid inlets 21a, 21b, 21c through the coating fluid buffering sections 211, 212, 213 to the coating fluid passages 21a', 21b', 21c'. The auxiliary fluid passages 22a, 22b, 22c are connected to the auxiliary fluid inlet 22.
The size of the coating fluid passage 21a', 21b', 21c' is smaller than that of the coating fluid buffering sections 211, 212, 213 and that of the coating fluid inlets 21a, 21b, 21c. A two-phase fluid generator 5a, 5b, 5c is arranged at a junction between the coating fluid passage 21a', 21b', 21c' and the corresponding auxiliary fluid passage 22a, 22b, 22c.
Each of the two-phase fluid output sections 23a, 23b, 23c comprises a two-phase fluid inlet 231, 232, 233 at one end and a two-phase fluid outlet 24a, 24b, 24c at the other end. The two-phase fluid inlets 231, 232, 233 are respectively connected to the two-phase fluid generators 5a, 5b, 5c for conveying the two-phase fluids 11 generated by the two-phase fluid generators 5a, 5b, 5c. The two-phase fluid outlets 24a, 24b, 24c are arranged at the bottom of the coating die 2 and kept at a predetermined distance from the surface of the substrate 6, such that the two-phase fluids 11 flow from the two-phase fluid output sections 23a, 23b, 23c out through the fluid outlets 24 of the coating die 2.
In practical applications, the auxiliary fluid 3 may comprise a liquid or a gas immiscible with the coating fluids 2a, 2b, 2c. After flowing out of the fluid outlet 24 of the coating die 2, the two-phase fluid 11 are coated at predetermined locations of the substrate 6 by the movement of the coating die 2 and the substrate 6 along a parallel direction relative to each other. In the case a gas is used as the auxiliary fluid, micro patches 7a, 7b, 7c are directly formed on the substrate. In the case a liquid that is immiscible with the coating fluids 2a, 2b, 2c is used as the auxiliary fluid 3, the substrate 6 could be heated to vaporize the auxiliary fluid 3 by baking, leaving the coating fluid 2a, 2b, 2c to form the micro patches 7a, 7b, 7c.
Please refer to
The coating fluids 2a are delivered through the coating fluid inlet 21 a to the coating fluid buffering section 211 and then to the coating fluid passage 21 a' . The auxiliary fluid 3 is delivered from the auxiliary fluid inlet 22 to the auxiliary fluid passage 22a. After a predetermined amount of the coating fluid 2a flows through the interceptor 5a1 to generate a segment 2a' of a predetermined length in the two-phase fluid output section 23a, the interceptor 5a1 intercepts the flowing of the coating fluid 2a. In turn, the intercepted 5a1 allows the auxiliary fluid 3 to flow from the auxiliary fluid passage 22a. After a predetermined amount of the auxiliary fluid 3 flows through the interceptor 5a1 to generate a segment 3' of a predetermined length in the two-phase fluid output section 23a, the interceptor 5a1 intercepts the flowing of the coating fluid 2a. The interception actions of the interceptor 5a1 to the coating fluid flow and to the auxiliary fluid flow are proceeded alternatively, forming a two-phase fluid 11 in the two-phase fluid output sections 23a. The auxiliary fluid 3 remains immiscible with the coating fluid 2a.
In the embodiment mentioned above, the two-phase fluid generators are arranged in the micro channel structure 4 inside the coating die 2, forming the two-phase fluid. In practical application, the two-phase fluid generators may be arranged at an exterior of the coating die 2 for forming the two-phase fluid just as well.
As shown in
Please refer to
Furthermore, both the driving mechanism 21 and the panel driving mechanism 6a may be used at the same time. The driving mechanism 21 drives the coating die 2 to move and the panel driving mechanism 6a drives the substrate 6 to move simultaneously along a horizontal direction I to allow parallel and opposite movements. In this way, the coating procedure is speeded up for improving the production efficiency. In practical application, if the auxiliary fluid 3 is a gas, either the coating die 2 or the substrate 6 may be driven to move both in a direction perpendicular to the surface of the substrate 6 of
In the case when the auxiliary fluid 3 is a gas, either the coating die 2 and the substrate 6 can also be arranged to move in a direction perpendicular to the surface of the substrate 6 of
After the coating die is prepared, a coating fluid is supplied to the micro channel structure of the coating die from the coating fluid inlet at step 102. An auxiliary fluid is supplied to the auxiliary fluid inlet of the micro channel structure at step 103.
The flowing of the coating fluids and the flowing of auxiliary fluid are alternatively intercepted by a two-phase fluid generator (Step 104), generating a two-phase fluid comprising a segment of coating fluid of a predetermined length and a segment of auxiliary fluid of a predetermined length.
In step 105, the two-phase fluid are conveyed to the two-phase fluid output section, and then flows through the two-phase fluid outlet of the fluid output section to the fluid outlet of the coating die at step 106.
Lastly, the coating die and the substrate are allowed to move in parallel and opposite direction, allowing the two-phase fluids to flow out of the coating die and coat at predetermined locations on the substrate, defining micro patches directly at step 107a in the case that the auxiliary fluid is a gas. In the case that the auxiliary fluid is a liquid immiscible with the coating fluid, the substrate is heated to vaporize the auxiliary fluid by baking, leaving the coating fluid to define micro patches at step 107b.
The coating fluid 2a flows from the coating fluid inlet 21a, through the coating fluid buffering section 211 and the coating fluid passage 21a' to the two-phase fluid generator 5a. The auxiliary fluid 3 flow from the auxiliary fluid inlet 22 and the auxiliary fluid passage 22a to the two-phase fluid generator 5a. As shown in
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.