JP2008305668A - Evaluation method of liquid discharging head, and liquid applying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately measure an amount of discharge at each nozzle to uniformly apply all patterns, when forming a film by ink jet direct drawing such as drawing when forming an SED element film. <P>SOLUTION: This evaluation method of a liquid discharging head includes liquid in which an application substance is dispersed or dissolved, the liquid discharging head having a nozzle to discharge the liquid as a liquid drop, a liquid applying device to apply an application substance on the surface of an object to be applied by discharging the liquid drop from the liquid discharging head, a shape measuring means to measure a three-dimensional shape value of the application substance applied and deposited on the object to be applied, and a volume calculating means to calculate a volume value of the application substance from the shape-measured value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for evaluating a liquid discharge head for applying a liquid in which a coating substance is dispersed or dissolved, and further relates to a method and apparatus for applying a liquid in which a coating substance is dispersed or dissolved, for example, an ink jet drawing apparatus. The present invention relates to an electron-emitting device, an apparatus for manufacturing an electron source substrate, an electron source, a display panel, and the like using the device, and a liquid discharge head evaluation method thereof.

  A surface conduction electron-emitting device used for electron source substrates, electron sources, display panels, etc. is a phenomenon in which electrons are emitted when a current flows parallel to the film surface through a small-area thin film formed on the substrate. Is to be used. A configuration example of the surface conduction electron-emitting device is shown in FIGS.

  FIG. 8 is a schematic diagram showing an example of an electron-emitting device to which the ink jet ejecting apparatus of the present invention can be applied. FIG. 9 is a diagram showing an example of a surface conduction electron-emitting device that can be manufactured using the ink jet ejecting apparatus.

  In FIGS. 8 and 9, 1 is a substrate, 2 and 3 are element electrodes, 4 is a conductive thin film, 5 is an electron emitter, 7 is a droplet applying device, 24 is a droplet, and 25 is a conductive thin film before energization forming. It is.

  In this example, first, the device electrodes 2 and 3 are formed on the substrate 1 with a distance of L1 (FIG. 9A). Next, a droplet 24 made of a solution containing a metal element is discharged from a droplet applying device (inkjet recording device) 7 (FIG. 9B), and the conductive thin film 4 is formed so as to be in contact with the device electrodes 2 and 3. (FIG. 9C). Next, for example, by a forming process described later, a crack is generated in the conductive thin film to form the electron emission portion 5.

  By using such a droplet application method, minute droplets of the contained solution can be selectively formed only at a desired position, so that the material constituting the element portion is not wasted. In addition, a vacuum process requiring an expensive apparatus and patterning by photolithography including a large number of steps are unnecessary, and the production cost can be reduced.

  If a specific example of the droplet applying device 7 is given, any device can be used as long as it is an apparatus capable of forming an arbitrary droplet. In particular, the control is performed in the range of about several tens to several tens of ng. An ink jet type apparatus that can easily form a minute amount of droplets of about 10 ng to several tens of ng is preferable.

  A method for producing a surface conduction electron-emitting device using an ink jet ejecting apparatus is described in JP-A-11-354015.

The conductive thin film 4 is particularly preferably a fine particle film composed of fine particles in order to obtain good electron emission characteristics. The film thickness is determined by the step coverage to the device electrodes 2 and 3, the resistance value between the device electrodes 2 and 3, and Although it is appropriately set depending on energization forming conditions and the like described later, it is preferably several to several thousands, and particularly preferably 10 to 500. The sheet resistance value Rs is 10 ³ to 10 ⁷ Ω / □.

The material forming the conductive thin film 4 is Pd, Pt, Ru, Ag, Au, Ti, In, Cu, Cr, Fe, Zn, Sn, Ta, W, Pb, or other metals, PdO, SnO ₂ , In _2. Oxides such as O ₃ , PbO, Sb ₂ O ₃ , borides such as HfB ₂ , ZrB ₂ , LaB ₆ , CeB ₆ , YB ₄ , GdB ₄ , carbides such as TiC, ZrC, HfC, TaC, SiC, WC And nitrides such as TiN, ZrN, and HfN, semiconductors such as Si and Ge, and carbon.

  The fine particle film described here is a film in which a plurality of fine particles are aggregated, and the fine structure is not only in a state where the fine particles are individually dispersed and arranged, but also in a state where the fine particles are adjacent to each other or overlap (including island shapes). It refers to a membrane, and the particle size of the fine particles is from several to several thousand, preferably from 10 to 200.

  Examples of the solution on which the droplets 24 are based include those obtained by dissolving the constituent material of the conductive thin film described above in water, a solvent, or the like, or an organic metal solution.

As the substrate 1, quartz glass, glass with a low impurity content such as Na, blue plate glass, a glass substrate on which SiO ₂ is formed, and a ceramic substrate such as alumina are used.

As a material for the device electrodes 2 and 3, a general conductive material is used. For example, a metal or alloy such as Ni, Cr, Au, Mo, W, Pt, Ti, Al, Cu, Pd, and Pd, Appropriately selected from printed conductors composed of metals such as Ag, Au, RuO ₂ , Pd—Ag, or metal oxides and glass, transparent conductors such as In ₂ O ₃ —SnO ₂ , and semiconductor materials such as polysilicon. Is done.

  The electron emission portion 5 is a high-resistance crack formed in a part of the conductive thin film 4 and is formed by energization forming or the like. The crack may have conductive fine particles having a particle diameter of several to several hundreds. The conductive fine particles contain at least a part of elements constituting the conductive thin film 4. Moreover, the electron emission part 5 and the electroconductive thin film 4 of the vicinity may have carbon and a carbon compound.

  The electron emission portion 5 is formed by performing an energization process called energization forming of an element formed with the conductive thin film 4 and the element electrodes 2 and 3. As described in Japanese Patent Application Laid-Open No. 2-56822, the energization forming is performed by energizing between the element electrodes 2 and 3 from a power source (not shown) to locally break, deform or alter the conductive thin film 4, A site whose structure has been changed is formed. This region where the structure is locally changed is referred to as an electron emission portion 5. The voltage waveform of the energization forming is preferably a pulse shape, and there are a case where a voltage pulse having a constant pulse peak value is applied continuously and a case where a voltage pulse is applied while increasing the pulse peak value.

  When a voltage pulse is applied while increasing the pulse peak value, the pulse peak value (peak voltage during energization forming) is increased by, for example, about 0.1 V step and applied in an appropriate vacuum atmosphere.

  In this case, the energization forming process is performed by measuring the element current at a voltage at which the conductive thin film 4 is not locally broken or deformed, for example, at a voltage of about 0.1 V, and obtaining a resistance value, for example, a resistance of 1 MΩ or more. The energization forming ends when indicated.

Next, it is desirable to perform a process called an activation process on the element for which energization forming has been completed. The activation step is, for example, a process of repeatedly applying a voltage pulse having a constant pulse peak value at a degree of vacuum of about 10 ⁻⁴ to 10 ⁻⁵ Torr and the same as the energization forming. In this process, carbon and carbon compounds derived from materials are deposited on a conductive thin film, and the device current If and the emission current Ie are remarkably changed. The activation process ends when, for example, the emission current Ie is saturated while measuring the device current If and the emission current Ie.

  Here, carbon and carbon compound are graphite (refers to both single crystal and polycrystalline) and amorphous carbon (refers to a mixture of amorphous carbon and polycrystalline graphite), and the film thickness is 500 mm. The following is preferable, and more preferably 300 mm or less.

  The electron-emitting device fabricated in this way is preferably operated and driven in an atmosphere having a higher degree of vacuum than the degree of vacuum in the energization forming process and the activation process. In addition, it is desirable to drive the operation after heating at 80 ° C. to 150 ° C. in an atmosphere with a higher degree of vacuum.

The degree of vacuum higher than that of the energization forming process and the activation treatment is, for example, a degree of vacuum of about 10 ⁻⁶ Torr or more, more preferably an ultra-high vacuum system, and carbon and carbon compounds are newly made conductive. The degree of vacuum hardly deposits on the thin film. By doing so, the device current If and the emission current Ie can be stabilized.

  A planar surface conduction electron-emitting device can be manufactured as described above.

  FIG. 2 shows an external view of an ink jet ejecting apparatus for producing a surface conduction electron-emitting device.

  In FIG. 2, 101 is a housing for storing the control device, 102 is a monitor of a personal computer stored in the housing, 103 is a personal computer keyboard or operation panel, 104 is a stage on which a substrate is mounted, and 105 is an inkjet head that ejects liquid. , 106 is a substrate on which the surface conduction electron-emitting device is formed, 107 is an XY stage that freely moves in both vertical and horizontal directions so that droplets can be applied to any position on the substrate 106, and 108 is the entire inkjet ejecting apparatus A platen 109 for holding the liquid crystal is an alignment camera for aligning the droplet application position on the substrate 107.

  FIG. 14 is a schematic configuration diagram showing various embodiments of the electron-emitting device manufacturing apparatus usable in this example, and FIG. 15 is a flowchart showing the steps of one embodiment of the electron-emitting device manufacturing method of this example. is there.

  In FIG. 14, 7 is an ink jet ejecting apparatus (droplet applying apparatus), 8 is a light emitting means, 9 is a light receiving means, 10 is a stage, 11 is a controller, and 12 is a control means. In the light emitting means and the light receiving means referred to here, the object to be generated / received is not limited to light, and any object can be used as long as it can be recognized as a signal. There are diodes and infrared lasers. Further, the light receiving means may be any one that can receive a signal in accordance with the light emitting means. Further, these light emitting means and light receiving means may be configured to generate or receive signals that are transmitted or reflected through the insulating substrate.

  Items relating to the state of the liquid droplet detected in the method and apparatus for manufacturing the electron-emitting device of this example are the amount of liquid droplet applied to the gap, which is a recess between the pair of device electrodes, the position of the liquid droplet, The presence / absence of a droplet itself. Based on the acquired information regarding such items, the number of ejections and the ejection position, and in the inkjet ejecting apparatus using piezoelectric elements, the ejection parameters of the inkjet ejecting apparatus including the driving conditions are controlled by the control means.

  Further, as means for performing the above detection, there are a droplet information detecting means for detecting the presence / absence and amount of a droplet discharged from a nozzle by an ink jet method, and a landing position for detecting a position where the droplet has landed And detecting means.

  In this case, the landing position detection means optically detects an electrode pattern or a dedicated alignment mark before ejection, or optically detects the modulation of transmittance by the droplet after ejection, after landing. The position of the droplet is detected. Note that the position of the droplet is detected by detecting the transmittance at a plurality of points in the gap and in the vicinity of the gap, and taking the correlation therebetween.

  As shown in FIG. 15, in the manufacturing method of this example, the liquid application position is detected by detecting light passing between the electrodes or reflected light by the light emitting means and the light receiving means using the electrode interval, The head of the inkjet apparatus is moved to a position where droplets can be applied between the electrodes (positioning step). Next, droplets are applied between the electrodes by the ink jet ejecting apparatus (droplet applying step), and, for example, whether the droplets are applied between the electrodes by a signal that passes or reflects between the electrodes as in the alignment step. (Information on the presence or absence of the above-mentioned droplet itself) is detected (droplet detection step). Then, if a droplet is applied to a desired region at a desired position in the droplet detection step, the process proceeds to the next alignment step between electrodes. If no droplet is applied, the droplet is applied again.

  In addition, dummy droplets for information detection are preliminarily discharged to locations other than between the device electrodes, and the discharge conditions are set to an appropriate one based on the detection results, and then the droplet discharge between the device electrodes is performed. There is also a method.

  As a method for controlling the discharge conditions, the detection signal difference component of the droplet information is used as a correction signal, and parameters such as drive pulse height, pulse width, pulse timing, and number of pulses are set so that the detected value is held at an optimum value. There are a method of feedback control of at least one in real time, a method of correcting at least one of the parameters according to an algorithm determined in advance according to the amount of deviation of the detected value from the optimum value, and the like.

  The position detection means optically detects an electrode pattern or a dedicated alignment mark before discharging, or optically detects the modulation of transmittance by the discharged droplet, thereby determining the position of the droplet after landing. To detect. In that case, the position of the droplet is detected by detecting the transmittance at a plurality of points in the gap and in the vicinity of the gap, and taking the correlation therebetween.

  After the thin film is applied by the above method, the conductive thin film is formed by heat treatment to evaporate the solvent. Subsequent forming and the like are performed in the same manner as described above.

The above substrate alignment method, conductive thin film forming method, and forming method are described in JP-A-11-354015. Further, a method of manufacturing a display panel using the surface conduction electron-emitting device manufactured by the above method is described in Japanese Patent Laid-Open No. 11-354015.
JP-A-11-354015 Japanese Patent Laid-Open No. 2-56822 JP-A-9-48111 JP 2000-193814 A JP 2001-147317 A US Pat. No. 4,340,306

  When a display panel is manufactured by arranging the above-described surface conduction electron-emitting devices on a flat surface, the variation in the size of the electron source becomes the variation in the luminance of each pixel of the display panel, which is the image quality of the display panel. Greatly affects quality. Therefore, it is desirable that the element film forming liquid applied by the liquid applying apparatus has the same size for all droplets. Otherwise, the variation in the size of the liquid droplets for forming the element film becomes the variation in the electron source element film, resulting in uneven brightness of the display panel.

  In particular, the use of a liquid coating apparatus having a plurality of nozzles is effective for increasing the production efficiency of element film formation. However, if the discharge amount for each nozzle varies, the electron source element film varies, and the display panel The brightness becomes uneven.

  Therefore, it is necessary to accurately measure the liquid amount of the discharged droplets. In particular, it is necessary to accurately measure the amount of liquid droplets discharged for each nozzle. For this purpose, the first method is a liquid consumption measurement method, and the second is a method for measuring the absorbance of coated droplets.

  The first liquid consumption measuring method is a method of continuously discharging droplets under the same conditions as those applied to a substrate, collecting all discharged liquids, and measuring the weight or volume of the discharged liquids, Alternatively, the ink amount in the ink tank is measured and compared with the weight or volume before and after ink consumption. An electronic microbalance is used to measure a minute weight, and a micropipette is used to measure a minute volume. In these methods, it takes time to collect the minimum amount of liquid necessary for measuring the weight or volume of the liquid, and the measurement accuracy is low. Also, with this method, the average amount of a plurality of droplets can be measured, but the discharge amount variation of one discharge cannot be measured. However, it is necessary and important to measure the discharge amount variation of one discharge at a time in order to evaluate the coating stability of the liquid coating apparatus and to ensure the quality of the display panel.

  The second method for optically measuring applied droplets is a method in which a droplet landed on a substrate is read by a camera, and the weight or volume of the droplet is measured from the absorbance of the droplet landed by image processing on the read image. This method is described as a discharge amount measuring method in a color filter manufacturing apparatus in JP-A-9-48111, JP-A-2000-193814, JP-A-2001-147317, and the like. The method will be described.

  A fixed-size frame (hereinafter referred to as a window) as shown in FIG. 17 is applied to the image of the measurement target dot captured by the measurement camera. Originally, in order to measure the density of the dot itself, it is desirable to integrate the density levels of all the smallest pixels within the range of the dot. However, when actually observing the dot with a microscope, the density in the peripheral area is thin. It is extremely difficult to determine the boundary. Therefore, a window having a size in which the measurement target dot can surely enter (including the peripheral portion) is set, and the density levels of all the pixels in the window are integrated to obtain the integrated density of the measurement target dot.

  Before obtaining the integrated density of dots shown in FIG. 17, the window is first applied to a place where there are no printed dots to obtain the integrated luminance in the window, and this is the state where the absorption rate of transmitted light is the lowest (that is, the density is the lowest). Is set as a reference integrated luminance. Then, the actually obtained luminance of the measurement target dot is divided by the reference integrated luminance, and the reciprocal of the value is used as the absorption rate (density data) of the measurement target dot.

  Next, a method for obtaining a calibration curve that serves as a reference for measuring the amount of ink discharged per time discharged from an arbitrary nozzle of the inkjet head under an arbitrary condition will be described. First, as a first work, among the plurality of nozzles of the ink jet head for which the discharge amount is to be measured, the discharge amount of at least two or more nozzles that differ as much as possible in a single discharge amount under a certain condition is described above. Obtain by measurement method. That is, ink is ejected from a desired nozzle a predetermined number of times, the total weight of the ejected ink is measured, and this is divided by the number of ejections to obtain the ejection amount per nozzle.

  Next, ink is ejected from the plurality of nozzles whose ejection amount per time is thus determined under the same conditions as when the ejection amount is obtained, and these ink dots are formed on the glass substrate 10. Is measured by the method as described above. By performing such measurement, the amount of ink discharged from a plurality of nozzles and the density of ink dots formed by the ink are determined in a one-to-one correspondence.

  FIG. 18 is a graph plotting the relationship between the amount of ink discharged once for four different nozzles and the density of ink dots formed on the glass substrate by the ink. In FIG. 4, the black circles indicate the ink discharge amounts and ink dot densities of the four nozzles. From this figure, it can be seen that the four points are on a substantially straight line. Therefore, if a straight line passing through these four points is drawn, the density of the ink dots with respect to an arbitrary ejection amount is uniquely determined as a point on the straight line. This straight line is called a calibration curve.

  Thereafter, the dot density of the ink ejected from an arbitrary nozzle under an arbitrary condition can be measured by the above method, and the ink ejection amount of the nozzle can be obtained from the calibration curve.

  FIG. 19 is a view showing a printing apparatus incorporating a discharge amount measuring apparatus as described above. In FIG. 19, 51 has an image processing function, and further a personal computer (hereinafter referred to as a PC) for controlling the printing apparatus and the discharge amount measuring portion, 52 is a printer main body, 53 is a printer stage on which a printing object is placed, and 54 is an inkjet. In this embodiment, printing is performed while the head moves left and right. 55 is a printing object such as paper, 56 is a CCD camera, 57 is a microscope for enlarging printing dots, 58 is a microscope stage (which is hollow so that a transmissive light source can be used), 59 is a transmissive light source, and 60 is transparent such as glass. A substrate 61 is a roller for moving the transparent substrate 60 on the microscope stage 58.

  In the above apparatus, the print head 54 prints on the print object 55 while moving left and right. When a predetermined time or a predetermined number of lines are printed throughout the printing period, the print head 54 moves to the transparent substrate 60 and prints dots using the nozzles currently used for printing. The density of the printed dots is measured by the transparent substrate 60 moving under the microscope 57 and using the transmission light source 59 and the CCD camera 56 by the method described above. Next, the PC 51 instantly converts the measured density into an ink discharge amount based on the calibration curve that has already been obtained. If the ink discharge amount exceeds the specified range, a pulse is given to the head nozzle. Control is performed so that the ink discharge amount is appropriate by changing the width and the like.

  With the above method, in the color filter manufacturing apparatus, it is possible to accurately measure the discharge amount of each nozzle once.

  However, the situation is different in the case where an electron-emitting device and an electron source substrate, an electron source, a display panel, and the like using the ink-jet drawing apparatus are manufactured by the same method.

  Even if droplets made of a solution containing a metal element are applied to the substrate by the above-described method, the solution is not colored like the color filter ink. If the metal-containing solution contains neither a pigment component nor a color component, the droplets or dots applied on the substrate become nearly transparent. The closer the droplet color is to transparent, the lower the accuracy of the measurement method that measures the droplet amount based on the density of the image captured by the CCD camera, as used in the above-described color filter manufacturing apparatus.

  In the meantime, in a method instead of the optical density measurement method, for example, the ink weight measurement method, the measurement accuracy is low and the droplet amount for each application droplet cannot be easily measured. Measuring the discharge amount variation of each discharge is necessary and important for evaluating the coating stability of the liquid coating apparatus and ensuring the quality of the display panel.

  In order to solve the above problems, a liquid discharge head evaluation method of the present invention includes a liquid in which a coating material is dispersed or dissolved, a liquid discharge head including a nozzle that discharges the liquid as droplets, and the liquid discharge head. A liquid application apparatus that discharges the droplets to apply the application substance on the surface of the object to be applied; a shape measuring unit that measures a three-dimensional shape value of the application substance applied and adhered onto the object to be applied; Since the volume calculation means for calculating the volume value of the coating substance from the shape measurement value is used, and the liquid discharge amount performance of the liquid discharge head is evaluated using the volume value, it is performed once for each nozzle. The liquid discharge amount for each can be measured with high accuracy.

  Furthermore, in the liquid coating apparatus of the present invention, a liquid in which a coating substance is dispersed or dissolved, a liquid ejection head having a nozzle that ejects the liquid as droplets, and the droplets are ejected from the liquid ejection head. A liquid application device that applies the above-mentioned application substance to the surface of the application object, a nozzle discharge amount control means that controls the liquid discharge amount from the nozzle, and a three-dimensional shape of the application substance that has been applied and adhered onto the object to be applied A shape measuring means for measuring the value and a volume calculating means for calculating the volume value of the coating substance from the shape measured value, and a control means for controlling the liquid discharge amount using the volume value. The discharge amount from the nozzle of the coating apparatus can be controlled to a desired value.

  Furthermore, the liquid discharge amount from the nozzle can be controlled so that the coating amount of the coating material to be applied in a predetermined region on the surface of the coating material becomes a desired value.

  Furthermore, when the present invention is used in a liquid application apparatus having a plurality of nozzles, the amount of liquid discharged from the nozzles so that the amount of liquid discharged from some or all of the plurality of nozzles is substantially constant. Will be able to control

  As described above, when the liquid discharge head discharge amount evaluation method of the present invention is used, it is possible to accurately measure the liquid discharge amount by measuring the three-dimensional shape value of the coating substance applied on the object to be coated. Therefore, the quality of the liquid discharge head or the basic discharge performance can be accurately evaluated.

  In addition, when the liquid application method and the liquid application apparatus of the present invention are used, it is possible to accurately measure the application amount of each drop and control the application accurately, so that a highly accurate liquid application method and liquid application apparatus are realized. can do.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  The droplet discharge amount measuring method of the present invention will be described with reference to FIG.

  In the present invention, a droplet is applied on a flat substrate, heated to form a dot film, and the volume of the applied droplet is calculated by calculating the volume from the shape of the dot film. taking measurement.

  Here, it is necessary to pay attention to the water repellency of the surface of the flat substrate to which the coating material used for measurement is applied. If the water repellency is too low, the droplets flow widely and a clean circular dot is not formed, so that the discharge amount measurement accuracy is lowered. On the other hand, even if the water repellency is too high, the droplets are attracted and gathered locally after landing on the substrate, so that clean circular dots are not formed, and the discharge amount measurement accuracy is lowered. In order to correctly measure the volume, it is desirable to use a glass substrate with an appropriate surface treatment.

  FIG. 1 is a diagram in which a three-dimensional shape of a dot obtained by applying a droplet on a flat glass substrate by an ink jet means and evaporating a liquid component by heat treatment is observed.

  FIG. 1 was observed using a stereomicroscope device named “New View 100” from ZYGO using scanning white light interferometry. The principle of scanning white interferometry adopted in this device is described in USP4340306 (N. Balasubramanian), etc., but it converts multiple interference intensity data accompanying reference mirror scanning into phase data. FIG. 5 shows a schematic configuration diagram of the method for measuring the wavefront shape.

  In FIG. 5, the light from a white light source (halogen lamp) is irradiated onto the surface to be measured through an objective lens that can scan in the optical axis direction. The light reflected from the test surface passes through the objective lens again, is reflected by the beam splitter, and an image of the test surface is formed on the CCD camera. Interference fringes appear in the image of the CCD camera due to the optical path difference between the objective lens and the test surface. This is called Fizeau fringes. When the light source is monochromatic light, clear interference fringes appear, but when the light source is white light, different interference fringes for each color can be observed with CCD.

  Next, the interference fringes are moved by moving the objective lens little by little to change the optical path length. If the part of the CCD screen where the interference intensity is the maximum, that is, the point where the difference between the light peak and the dark peak when the optical path length is shifted by moving the objective lens, is connected with a line, Shape contours are created. By further moving the objective lens at full scale, contour lines of any height can be created.

  In “New View 100”, in order to further increase the height resolution, the above processing is performed on all light wavelength components, and further by using the interference fringe analysis method, the resolution is much smaller than the light source light wavelength, That is, a small resolution of 0.3 nm in the height direction is realized.

  “New View 100” uses a scanning white light interferometry to realize a stereo microscope. In addition to this method, there is an apparatus called a scanning laser microscope that uses monochromatic light interference. . There is also a method of measuring the shape using a scanning electron microscope or an atomic force microscope.

  Next, a method for calculating the volume from the shape of the dot-like film using the shape measuring microscope as described above will be described. With the above-mentioned stereomicroscope, the unevenness data of the test surface can be obtained three-dimensionally. This data is expressed as a value of height Z from the test surface corresponding to all X and Y values, with a certain plane close to the test surface as the measurement reference surface and the reference surface expressed in XY coordinates. It is.

  Referring to FIG. 1, the horizontal direction in FIG. 1 is the X axis, the depth direction is the Y axis, and the height method is the Z axis. With regard to the measurement data, 320 pixels in the X axis direction and 240 pixels in the Y axis direction. Thus, Y-direction height data for a total of 76800 pixels is measured. FIG. 1 shows Y data on the XY coordinates displayed three-dimensionally. However, in order to make it easy to see in FIG. 1, the tilt correction processing is performed so that the tilt of the XY plane of the substrate is horizontal with the measurement reference plane. Further, the height direction is enlarged and displayed by about 2000 times compared to the plane direction.

  FIG. 1 shows the shape of a disk-shaped film having a diameter of about 0.06 mm and a height of about 0.03 μm on a flat substrate. If the columnar shape (actually disk-like shape) of the applied substance that is formed into a film by applying liquid in the form of dots in this way is smaller, use this type of stereo microscope. Then, since the shape of the part which cannot be seen from an upper surface cannot be grasped | ascertained, the volume of a coating substance cannot be calculated | required correctly from there. However, as shown in the figure, the volume of the coating substance can be obtained correctly if the shape is the same size at the top and bottom of the cylinder or the shape expands toward the bottom.

  FIG. 6 is a cross-sectional view in which the vicinity of the center of the coating substance in FIG. 1 is cut in the Y-axis direction. As shown in this figure, the measurement reference plane is inclined. Therefore, using only the data of the flat substrate portions on both sides, a plane approximation straight line is obtained as shown in the figure. In order to use only the data of the flat substrate portions on both sides, for example, a method of using only 1/5 data at both ends is used. In this case, it is premised that there is no coating substance in the region of 1/5 both ends in the Y-axis direction on the screen. The plane approximation straight line thus obtained is an oblique straight line in FIG.

  Next, the plane approximate straight line value is subtracted from each data value. Then, it becomes 7 in the figure. That is, the figure is a figure obtained by correcting the plane inclination of FIG.

  Next, in order to obtain the volume, the entire range of FIG. 7 is integrated. This integral value indicates the volume of a portion obtained by thinly slicing the vicinity of the center of the coating substance with a thickness of a pixel unit. In this integration, there is a method in which the part where the coating substance is not attached on both sides is excluded from the integration range for volume calculation, but this part is a part where the integration value is approximately ± 0 in terms of calculation. Therefore, the numerical results will not change even if they are not specifically excluded.

  Next, the above calculation process is similarly executed on 320 lines in the X direction. At that time, a plane approximate straight line value is obtained for each line, and plane inclination correction is performed for each line. Further, the integral value data corresponding to the 320 lines is added to obtain an overall integral value. In this case as well, the integral value at both ends of the X axis is approximately ± 0, so it is not necessary to exclude it from the calculation.

  The sum of the integral values obtained as described above corresponds to the volume value of the applied substance.

  By determining the concentration of the liquid coating material to a predetermined value, the volume value of the coating material is proportional to the discharge amount. Therefore, by measuring the amount of liquid consumed and the number of discharges for one sample, and further determining the volume value of the coating substance by the above method and determining the proportional coefficient of both, Thereafter, the liquid discharge amount can be known by obtaining the volume value of the coating substance.

  Next, a method for producing a surface conduction electron-emitting device using an ink jet ejecting apparatus using the above liquid discharge amount measuring means will be described.

  In the photolithography described below, an electron emission portion is formed in an electron emission portion formation region 1201 using a substrate (X wiring 72 and Y wiring 73) in which element electrodes as shown in FIG. Then, an electron source substrate on which a plurality of surface conduction electron-emitting devices are arranged is manufactured. Note that the X wiring and the Y wiring are electrically insulated by an insulating member (not shown) at the intersection. FIG. 9 is a diagram showing a manufacturing procedure of the surface conduction electron-emitting device. FIG. 8 is a plan view and a cross-sectional view of a surface conduction electron-emitting device manufactured according to this example.

  Element electrodes are formed on the substrate by photolithography according to the following procedure.

  (1) A quartz substrate is used as the insulative substrate 1, which is sufficiently washed with an organic solvent, and then the electrodes 2 and 3 made of Ni are formed on the substrate 1 by a general vacuum film forming technique and a photolithography technique. Form.

  (2) Next, one droplet (1 dot) of the organic palladium-containing solution is applied between the electrodes 2 and 3 by using an inkjet ejector using a piezoelectric element as the droplet applying device 7.

  (3) Next, heat treatment is performed to form a fine particle film made of palladium oxide (PdO) fine particles, and the thin film 4 is obtained. The fine particle film described here is a film in which a plurality of fine particles are aggregated, and as a fine structure thereof, refers to a film in which fine particles are adjacent to each other or overlap each other as well as a state in which fine particles are individually dispersed and arranged.

  (4) Next, a voltage is applied between the electrodes 2 and 3, and the thin film 4 is energized (energization forming process), thereby forming the electron emission portion 5.

  Using the electron source substrate thus manufactured, an envelope is formed by the face plate, the support frame, and the rear plate, sealing is performed, and a television display is performed based on a display panel and further an NTSC television signal. An image forming apparatus having a driving circuit for manufacturing the image forming apparatus is manufactured.

  As a result, an electron-emitting device manufactured by the manufacturing method of the present embodiment and an electron source substrate, a display panel, and an image forming apparatus manufactured using the electron-emitting device can be manufactured.

  FIG. 2 shows an external view of a liquid coating apparatus, that is, an ink jet ejecting apparatus for producing a surface conduction electron-emitting device.

  In FIG. 2, reference numeral 101 denotes a housing for storing the control device, 102 a personal computer monitor housed in the housing, 103 a personal computer keyboard or operation panel, 104 a stage on which the substrate is mounted, and 105 an inkjet head that ejects liquid. , 106 is a substrate on which the surface conduction electron-emitting device is formed, 107 is an XY stage that freely moves in both vertical and horizontal directions so that droplets can be applied to any position on the substrate 106, and 108 is the entire inkjet ejecting apparatus A platen 109 for holding the liquid crystal is an alignment camera for aligning the droplet application position on the substrate 107.

  FIG. 20 is a schematic block diagram of a discharge control system in forming a thin film by an ink jet method. Reference numeral 1 denotes a substrate in each unit cell, and 2 and 3 denote element electrodes facing each other. Reference numeral 1501 denotes an ejection nozzle of the ink jet ejecting apparatus, and 1502 denotes an information detection optical system for droplets. Reference numeral 1503 denotes a displacement control mechanism that includes an ink jet cartridge including a discharge nozzle, an ink tank, and a supply system, and a detection optical system. The displacement control mechanism 1503 includes a coarse movement mechanism that transfers between unit cells on a matrix wiring electrode substrate, and a unit cell. And a fine movement mechanism for finely adjusting the horizontal position and adjusting the distance between the substrate and the discharge nozzle. For example, in a piezo-type ink jet apparatus, the discharge amount per time is determined by the pulse height, pulse width, pulse timing, number of pulses, and the like of a voltage pulse fed to a piezo element that extrudes a metal-containing liquid.

  The discharge condition control circuit 1507 controls the droplets discharged from the discharge nozzle 1501 by controlling any one of the pulse height, pulse width, pulse timing, and pulse number of the voltage pulse fed to the piezoelectric element that pushes out the metal-containing liquid. The amount is controlled so as to be a desired value.

  By the above method, the amount of droplets discharged from all the used nozzles becomes a constant desired value.

FIG. 11 shows the circuit configuration of the ejection condition correction circuit of this embodiment.
A circuit connected to the head 303 includes a coating pattern data serial / parallel conversion circuit 322 for converting coating pattern serial data 319 for selecting whether or not each nozzle of the nozzle is discharged from the drawing control unit 311 into parallel data, and the converted data. Image data latch circuit 321 latched by data latch signal 318 Further, each Ch nozzle is selected based on this latch data, and the drive signal for driving the ejection drive element 309 of this nozzle is driven by drive timing signal 317 An ejection drive signal is supplied to the head from the output charge / discharge circuit 316 of the nozzle drive circuit 304 via the signal pattern output circuit 320. In the case of a piezo head, the ejection drive element corresponds to a piezoelectric element used on the ejection drive side wall of the ink chamber of the nozzle.

  At this time, the circuit configuration for controlling the discharge amount described in this embodiment is a case where the discharge amount is controlled by a pulse of a voltage pulse fed to the piezo element. A signal reference voltage circuit 314, a signal voltage control circuit 313, and an output voltage amplifier circuit 315 are configured.

  The signal reference voltage circuit 314 and the signal voltage control circuit 313 receive a command of the set control voltage value from the drawing control unit, the signal reference voltage circuit 314 sets the center value of the drawing voltage, and the signal voltage control circuit sets the center of each nozzle. Set the correction voltage for the voltage value.

  The output voltage amplification circuit 315 supplies a drive voltage to the output charge / discharge circuit 316 based on the corrected control voltage.

  FIG. 10 shows a circuit diagram example of the output charge / discharge circuit 316 in FIG.

  In FIG. 10, Tr is a transistor or FET. IN1 is a TTL level drive signal. Vcc is a DC stable voltage set to an arbitrary voltage value.

  In FIG. 10, when IN1 is at a high level, Tr1 and Tr2 are turned ON, TR3 is turned ON and Tr4 is turned OFF, current is discharged from OUT1, and OUT1 becomes a desired voltage.

  In FIG. 10, when IN1 is at a low level, Tr1 and Tr2 are turned off, TR3 is turned off and Tr4 is turned on, current is sucked into OUT1, and OUT1 becomes a ground level or a low voltage level. As described above, the corrected drive signal is output to the head from the output charge / discharge circuit circuit independently for each nozzle, and the ejection amount of the head is controlled.

  The procedure for controlling the discharge amount for each nozzle using the above-described discharge amount control means for each nozzle will be described with reference to the flowchart of FIG.

  In order to control the discharge amount for each nozzle using the discharge amount control means for each nozzle, first, the discharge amount for each nozzle of the head and variable characteristics of variable conditions (here, the discharge amount is variable by the drive voltage) are measured. The nozzle is measured under the condition of a voltage range in which the characteristics before and after the voltage value scheduled to be used for discharge amount control can be predicted. For example, set the voltage value with a small discharge amount and the voltage value with a large discharge amount to at least two or more points and apply coating to check the discharge amount under the condition of the drive signal of the same pulse width used at the time of drawing. On the substrate. In order to easily measure the shape with a microscope, this coating is performed so that a single dot of ink drops forms a circular dot. Alternatively, a predetermined number of droplets are overlaid at the same location to form a circular dot shape that can be easily measured by a microscope.

  The coated substrate is heat-treated to form a circular film of the coating material on the substrate.

  Next, in order to increase the measurement accuracy with a microscope, the optical reflectance between the glass substrate and the object to be inspected is made uniform by coating a noble metal such as platinum with a vacuum deposition bubble or the like.

  Next, the shape of the liquid on the glass substrate is measured with a stereoscopic microscope using a scanning white light interferometry or the like, and the volume value of the applied thin film is calculated from the shape value.

  Next, an ejection amount correction voltage control line as shown in FIG. 13 is obtained from the volume value and voltage value of three points of large, medium, and small voltages. Further, a voltage value corresponding to a desired predetermined volume is calculated from this line. However, the discharge amount correction voltage control line as shown in FIG. 13 is only shown here for the sake of explanation. Actually, a voltage value corresponding to a desired predetermined volume may be calculated by calculation in the control device arithmetic circuit.

  In the same manner, the volume of the applied substance with respect to the voltage values of all nozzles is measured from the drawing results of all nozzles under the drawing conditions used, the discharge amount correction voltage control line is calculated for each nozzle, and the voltage value corresponding to the desired predetermined volume Is calculated. The voltage value is set in the signal voltage control circuit 313.

  The series of calculations and settings described above are automatically calculated in a personal computer incorporated in the discharge control device.

  After the above setting, the discharge amounts of all the nozzles whose discharge drive voltages have been corrected and the volume value of the coated material are made uniform.

  FIG. 16 collectively shows the configuration and procedure of the apparatus for producing a uniform surface conduction electron-emitting device using the liquid discharge amount measuring means and the ink jet ejecting apparatus described above.

  In FIG. 16, first, a liquid application device (inkjet apparatus) is used to apply a liquid for discharge amount measurement with two or more voltage values to create a dot-like liquid application substrate, and a dot-like element film is formed using a heat treatment device. Create a 3D shape measurement substrate by depositing a noble metal film on the surface for microscopic observation with a vacuum evaporation system, measure the 3D shape with a 3D shape measurement microscope, and measure the 3D shape measurement value or the volume of coated deposits. Get. After the correction calculation for each nozzle and the drive voltage value setting for each nozzle based on the result from the measured value, the discharge amount is made uniform, liquid is applied to the non-coated substrate, and when it is heat-treated, a uniform element is obtained. A substrate with a film is completed.

  The liquid applicator measures the amount of droplets when the coating head is changed, when the coating conditions change, when the environmental conditions change, etc., and until the next droplet amount measurement, the voltage pulse that feeds the piezoelectric element is measured. The pulse height, pulse width, pulse timing, and number of pulses are controlled under the same conditions. As the substrate to be coated, a predetermined dedicated substrate for measuring the amount of droplets, for example, a non-patterned transparent glass substrate whose surface has been washed and subjected to water repellent treatment is used. For example, after applying to a non-patterned transparent glass substrate with a pitch between dots as shown in FIG. 3 and aligning it on the XY control stage, the movement pitch in the X direction and Y direction of the stage is designated. Thereby, the density | concentration of the application dot of the same nozzle or the application dot of a different nozzle can be measured continuously. And the volume value of the coating material apply | coated by each nozzle is calculated | required with the coating material volume measuring method shown previously. From this data, one of the pulse height, pulse width, pulse timing, and number of pulses of the voltage pulse fed to the piezo element is controlled so that the ejection amount for each nozzle becomes a constant desired value.

  After forming droplets by the above method, a voltage is sequentially applied between the device electrodes, and the thin film is energized (forming) to form an electron emission portion at the center of the device electrode gap of each cell.

  When the electron source substrate formed in this way is attached to the electron emission characteristic evaluation apparatus shown in FIG. 5 and emits electrons, the electron emission characteristics of all the elements become uniform.

  Further, a drive circuit for forming an envelope with a face plate, a support frame, a rear plate, etc. using the electron source substrate thus formed, sealing, and performing a display panel and further a television display When an image forming apparatus having the above is produced, all elements emit electrons and the characteristics become uniform. Thereby, it is possible to form a good TV image without luminance variation.

  In addition, the present invention controls not only the case of manufacturing an electron source substrate for a display panel but also a liquid application device that controls the amount of liquid discharged from each nozzle of the liquid droplet application device by using a liquid application device that is transparent or nearly transparent. By doing so, it is useful when trying to apply uniformly on the object to be applied.

  A plurality of nozzles are provided, and the amount of liquid discharged from the nozzles is controlled so that the amount of liquid discharged from some or all of the nozzles is substantially constant. According to the invention, it is possible to accurately control the application amount by accurately measuring the application amount of each drop.

  Alternatively, even if the discharge amount of the liquid discharged from the plurality of nozzles is not substantially constant, the plurality of nozzles can be used alternately to control the discharge amount to at least one of the plurality of nozzles. If this is arranged, the liquid discharge amount from the nozzle can be controlled so that the application amount of the application material applied in a certain area of the surface of the object to be applied becomes substantially constant. Therefore, since the application amount of each drop can be accurately measured and application control can be performed with high accuracy, a highly accurate liquid application method and liquid application apparatus can be realized.

  Furthermore, the present invention is useful not only when uniformly applying on an object to be applied, but also when applying with a desired application amount with high accuracy by using an application amount pattern on the object to be applied.

  As described above, when the liquid discharge head discharge amount evaluation method of the present invention is used, it is possible to accurately measure the liquid discharge amount by measuring the three-dimensional shape value of the coating substance applied on the object to be coated. Therefore, the quality of the liquid discharge head or the basic discharge performance can be accurately evaluated.

  In addition, when the liquid application method and the liquid application apparatus of the present invention are used, it is possible to accurately measure the application amount of each drop and control the application accurately, so that a highly accurate liquid application method and liquid application apparatus are realized. can do.

  Furthermore, if the electron emission portion of the display panel is manufactured using the liquid coating method of the present invention of the present invention, the conductive thin film constituting the electron emission element can be uniformly arranged, so that high image quality can be obtained. The display panel can be manufactured.

  Alternatively, the above invention is used when manufacturing an electron-emitting device and an electron source substrate, an electron source, a display panel, and the like using the ink-jet drawing apparatus, and some or all of the plurality of nozzles If the amount of liquid discharged from the nozzles is controlled so that the amount of liquid discharged from these nozzles is substantially constant, the size of the electron-emitting device can be manufactured to be constant.

  Alternatively, in the case where the above-described invention is applied with a desired application amount in a predetermined cell region on the substrate, the application product can be applied with high accuracy.

It is explanatory drawing explaining the method of the volume measurement of the coating substance which is a part of structural requirements of the Example of this invention, and is an output value of a three-dimensional shape measurement means. 1 is an external view of a liquid coating apparatus as an example of an embodiment of the present invention. It is a schematic diagram of the droplet application pattern at the time of measuring the droplet amount as an example of the embodiment of the present invention. It is a flowchart explaining the procedure of liquid discharge fixed liquid application by the droplet amount measuring method of this invention. FIG. 4 is an explanatory diagram of the operation principle of the three-dimensional shape measuring apparatus used in the present invention. It is a figure explaining the method of calculating a volume from the shape measurement value of the three-dimensional shape measuring apparatus used by this invention. It is a figure explaining the method of calculating a volume from the shape measurement value of the three-dimensional shape measuring apparatus used by this invention. It is a schematic diagram which shows an example of the electron emission element which can apply the inkjet liquid coating apparatus of this invention. It is a figure which shows the manufacture procedure of the surface conduction electron-emitting device which can be produced using an inkjet liquid application apparatus. It is an example of the circuit diagram of the output charging / discharging circuit 316 used with the liquid application apparatus of this invention. It is a circuit block diagram which shows the circuit structural example of the discharge amount correction circuit used by this invention. It is a schematic diagram of the electron source substrate for display panels manufactured by the manufacturing method of the present invention. It is explanatory drawing of the discharge amount correction voltage control line calculated and used by the discharge amount equalization liquid application means of this invention. It is the schematic which shows an example of the droplet provision process in the manufacturing method to which this invention is applied. It is a flowchart which shows the flow about an example of the manufacturing method to which this invention is applied. It is a figure which shows the whole structure of the liquid application apparatus without unevenness of this invention. It is explanatory drawing explaining the method of measuring the liquid discharge amount of a liquid application apparatus by measuring an optical dot density | concentration which is a prior art. It is explanatory drawing explaining the method of measuring the liquid discharge amount of a liquid application apparatus by measuring an optical dot density | concentration which is a prior art. It is the figure which showed the printing device which incorporated the measuring device of discharge amount. It is a schematic block diagram of the discharge control system in the thin film formation by the inkjet method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 2, 3 Element electrode 4 Conductive thin film 5 Electron emission part 6 Droplet provision apparatus (inkjet injection apparatus)
7 droplet 8 light emitting means 9 light receiving means 10 stage 11 controller 12 control means 24 droplet 25 conductive thin film before energization forming 303 inkjet head 304 head drive circuit 309 drive element 311 drawing control control unit 312 nozzle drive output circuit 313 voltage control Circuit 314 signal reference voltage 315 output voltage amplifier circuit 316 output charge / discharge circuit 317 drive timing signal 318 data latch signal 319 image serial data 320 drive signal pattern generation output circuit 321 image data latch output circuit 322 image data serial parallel conversion circuit

Claims (7)

A liquid in which a coating material is dispersed or dissolved, a liquid ejection head having a nozzle that ejects the liquid as droplets, and the droplets are ejected from the liquid ejection head to apply the coating material on the surface of an object to be coated. Liquid applicator, shape measuring means for measuring the three-dimensional shape value of the applied substance applied and adhered on the object to be applied, and volume calculating means for calculating the volume value of the applied substance from the shape measured value. Have
A liquid discharge head evaluation method for evaluating the liquid discharge amount performance of the liquid discharge head using the volume value. A liquid in which a coating material is dispersed or dissolved, a liquid ejection head having a nozzle that ejects the liquid as droplets, and the droplets are ejected from the liquid ejection head to apply the coating material on the surface of an object to be coated. A liquid application apparatus that performs the above, a nozzle discharge amount control unit that controls a liquid discharge amount from the nozzle, a shape measurement unit that measures a three-dimensional shape value of a coating substance that has been applied and adhered onto the object to be coated, Having a volume calculation means for calculating the volume value of the coating substance from the shape measurement value,
A liquid application method using a liquid application apparatus having a control means for controlling a liquid discharge amount using the volume value.   2. The liquid application method according to claim 1, wherein the liquid discharge amount from the nozzle is controlled so that the application amount of the application material applied in a predetermined region of the surface of the application object becomes a predetermined value.   2. The liquid application according to claim 1, comprising a plurality of nozzles, wherein the liquid discharge amount from the nozzles is controlled so that the discharge amount of the liquid discharged from some or all of the plurality of nozzles is substantially constant. Method. A liquid in which a coating material is dispersed or dissolved, a liquid ejection head having a nozzle that ejects the liquid as droplets, and the droplets are ejected from the liquid ejection head to apply the coating material on the surface of an object to be coated. A liquid application apparatus that performs the above, a nozzle discharge amount control unit that controls a liquid discharge amount from the nozzle, a shape measurement unit that measures a three-dimensional shape value of a coating substance that has been applied and adhered onto the object to be coated, Having a volume calculation means for calculating the volume value of the coating substance from the shape measurement value,
A liquid coating apparatus having a control means for controlling a liquid discharge amount using the volume value. A liquid in which a coating material is dispersed or dissolved, a liquid ejection head having a nozzle that ejects the liquid as droplets, and the droplets are ejected from the liquid ejection head to apply the coating material on the surface of an object to be coated. Liquid applicator, shape measuring means for measuring the three-dimensional shape value of the applied substance applied and adhered on the object to be applied, and volume calculating means for calculating the volume value of the applied substance from the shape measured value. Have
In the liquid discharge head evaluation apparatus that evaluates the liquid discharge amount performance of the liquid discharge head using the volume value,
A liquid coating apparatus that controls a liquid discharge amount from the nozzle so that a coating amount of a coating material to be applied in a predetermined region on a surface of the coating object becomes a predetermined value. A liquid in which a coating material is dispersed or dissolved, a liquid ejection head having a nozzle that ejects the liquid as droplets, and the droplets are ejected from the liquid ejection head to apply the coating material on the surface of an object to be coated. Liquid applicator, shape measuring means for measuring the three-dimensional shape value of the applied substance applied and adhered on the object to be applied, and volume calculating means for calculating the volume value of the applied substance from the shape measured value. Have
In the liquid discharge head evaluation apparatus that evaluates the liquid discharge amount performance of the liquid discharge head using the volume value,
A liquid coating apparatus that includes a plurality of nozzles, and controls a liquid discharge amount from the nozzles so that a discharge amount of liquid discharged from some or all of the plurality of nozzles is substantially constant.

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