JP2011062650A - Method of cleaning mask for organic el, program, device for cleaning mask for organic el, device for manufacturing organic el display, and organic el display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform laser cleaning of a mask for organic EL at a high cleaning degree without exerting excessive energy on the mask for organic EL when the laser cleaning is performed by scanning the mask for organic EL using a pulse laser. <P>SOLUTION: In a method of cleaning a mask for organic EL which removes vapor-deposited materials adhering to the mask 2 for organic EL by laser scanning, when the scanning is performed by intermittently irradiating a laser to the mask 2 for organic EL, circular removal areas from which the vapor-deposited materials are removed by the laser irradiation are partially overlapped, so that the removal areas cover the whole surface of a cleaning area, and the scanning is performed so as not to overlap the center of one removal area and the other removal areas. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an organic EL mask cleaning method, a program, an organic EL mask cleaning apparatus, an organic EL display manufacturing apparatus, and an organic EL display that perform cleaning by scanning an organic EL mask with laser light.

  2. Description of the Related Art Organic EL (Electro Luminescence) displays are widely used as low power consumption, lightweight, and thin image display devices that do not require a backlight. As the structure, an organic EL thin film layer is laminated on a transparent glass substrate, and the organic EL thin film layer adopts a structure in which a light emitting layer is sandwiched between an anode layer and a cathode layer. The light emitting layer is often formed as a thin film by vapor-depositing an organic material on a glass substrate, and each pixel region constituting the display is divided into three to deposit organic materials of three colors of RGB. . Therefore, vapor deposition is performed using an organic EL mask (shadow mask) in which a large number of openings are formed in order to deposit different color organic materials (organic dye materials) in the three regions of each pixel. The deposition process of the light emitting layer is completed by depositing each color deposition material while shifting the organic EL mask by the pixel pitch.

  When performing the vapor deposition process, the organic material adheres not only to the glass substrate but also to the organic EL mask. Since the mask for organic EL is not used only for one vapor deposition process but is used repeatedly, if a vapor deposition material adheres to the mask for organic EL when performing the next vapor deposition process, a new glass substrate will be used. Vapor deposition material is transferred and contaminated. In addition, an organic material is deposited on edge portions of the openings formed in the organic EL mask so that the area of the openings is partially or entirely blocked. Of course, if the entire area of the opening is blocked, or even if the area of the opening changes due to partial blocking, the deposition accuracy when using the organic EL mask is significantly reduced and it can be used. Is not. Therefore, the organic EL mask is periodically cleaned (preferably after completion of one vapor deposition process) to remove the vapor deposition material.

  As cleaning of the organic EL mask, wet cleaning using a surfactant or the like is mainly performed. Wet cleaning is cleaning performed by supplying a liquid to the organic EL mask. However, the organic EL mask to be cleaned is an ultrathin metal plate on the order of microns (several tens of microns), and a large amount of damage such as distortion or deformation is caused to the organic EL mask by the action of liquid pressure during wet cleaning. Given. In addition, when wet cleaning is performed using chemicals such as surfactants, a chemical solution supply mechanism and a drainage treatment mechanism for processing used chemicals (drainage) are required, which complicates the mechanism and causes environmental pollution due to drainage. There is also a problem.

  On the other hand, Patent Document 1 discloses a technique relating to cleaning (laser cleaning) performed by irradiating an organic EL mask with laser light as cleaning without using a chemical solution for wet cleaning. By irradiating the metal organic EL mask with laser light, a peeling force is applied between the organic EL mask and the organic material. The technique of Patent Document 1 is to perform cleaning by removing the organic material from the organic EL mask by this peeling force. And the adhesive film is affixed on the mask for organic EL, and the cleaning process is performed by transferring the peeled organic material to an adhesive film.

JP 2006-169573 A

  Laser cleaning that cleans the organic EL mask with laser light is performed by scanning one line toward the surface of the organic EL mask to form a scan line, and gradually shifting the scan line. . For example, when the galvanometer mirror disclosed in Patent Document 1 is used, scanning is performed by causing laser light oscillated from a laser light source to enter the galvanometer mirror and causing the mirror to vibrate slightly. At this time, a pulse laser is often used as the laser light source. The pulse laser oscillates laser light at a timing synchronized with a pulse having a very short time width, and repeats an oscillation state and a stop state. Thereby, the energy peak of the laser beam in the oscillation state is increased.

  Then, thermal shock or high temperature vaporization acts on the vapor deposition material adhering to the organic EL mask by the laser light irradiated toward the organic EL mask. Thereby, a vapor deposition substance is removed from the mask for organic EL. At this time, the cross section of the optical path of the laser light is circular, and the spot of the laser light irradiated on the organic EL mask is also circular, so the region of the vapor deposition material to be removed is also circular. This circular area (removal area) may coincide with the spot diameter of the laser beam, or may be greater than or less than the spot diameter. In any case, the scan line formed by scanning the laser beam has a shape in which a large number of circular removal regions are arranged in one row. The surface is cleaned by slightly shifting the scan lines formed in one row in a direction perpendicular to the scan direction.

  Accordingly, a large number of removal regions are arranged in the scanning direction (laser beam scanning direction) and the orthogonal direction (direction orthogonal to the scanning direction). Here, when scanning is performed by forming a number of removal regions using a pulse laser to form a scan line, there are two problems, that is, a cleaning degree problem and damage to the organic EL mask. The first problem is a problem caused by a gap between the removal regions. When a gap is generated between the removal regions, the vapor deposition material in the gap portion remains in the organic EL mask even though laser cleaning is performed. For this reason, a cleaning degree becomes low.

  Of course, when the removal areas are separated from each other, a gap is generated. However, a gap is also generated when scanning is performed so that the removal areas are in contact with each other. This is because a gap is inevitably generated when the circular shapes are arranged in contact with each other. Since this gap portion is not irradiated with laser light, the vapor deposition material remains, and the degree of cleaning is greatly reduced.

  On the other hand, when irradiation is performed so that the removal regions are overlapped with each other, the organic EL mask may be seriously damaged. The laser beam has a Gaussian intensity distribution, and its center is extremely high. Therefore, even if the removal regions are overlapped, if the center of one removal region and another removal region overlap, the intensity of the laser light becomes excessively strong. For this reason, there is a possibility that excessive energy that affects deformation such as distortion or warping is applied to the organic EL mask. As described above, the organic EL mask is repeatedly reused. However, if the mask itself is deformed, it cannot be reused.

  Therefore, the present invention has an object to perform cleaning with a high degree of cleaning without causing excessive energy to act on the organic EL mask when laser cleaning is performed by scanning the organic EL mask using a pulse laser. To do.

  In order to solve the above-mentioned problems, the organic EL mask cleaning method according to claim 1 of the present invention is a method for cleaning an organic EL mask that removes vapor deposition substances adhering to the organic EL mask by scanning laser light. When the scanning is performed by intermittently irradiating the organic EL mask with the laser light, a circular removal region of the vapor deposition material removed by irradiating the laser light is partially overlapped. Thus, scanning is performed so that the removal region extends over the entire cleaning area, and the center of one removal region and another removal region do not overlap.

  According to this organic EL mask cleaning method, since the removal region extends over the entire surface of the cleaning area, all the vapor deposition materials in the area are removed. Thereby, a high cleaning degree can be obtained. Since the laser beam is scanned so that the other removal region does not overlap the center of the removal region, excessive energy does not act on the organic EL mask.

  The organic EL mask cleaning method according to a second aspect of the present invention is the organic EL mask cleaning method according to the first aspect, wherein a scan line is scanned so that the plurality of removal regions are arranged in one direction. When scanning with a shift in a direction perpendicular to the direction, when the distance between the centers of two adjacent removal regions in the scan line and the shift amount of the scan line are L, and the radius of each removal region is R In addition, scanning is performed such that “R <L ≦ √2 × R”.

  According to this organic EL mask cleaning method, scanning is performed so as to satisfy the above formula. By setting “R <L”, the other removal region does not overlap the center of one removal region, and by setting “L ≦ √2 × R”, there is a gap between the removal region and the removal region. Will not occur, and the removal area can be applied to the entire area.

  The organic EL mask cleaning method according to a third aspect of the present invention is the organic EL mask cleaning method according to the first aspect, wherein a scan line is scanned so that the plurality of removal regions are arranged in one direction. When scanning in a direction orthogonal to the direction, the distance between the centers of two adjacent removal regions in each scan line, the distance between odd-numbered scan lines, and the distance between even-numbered scan lines Is L, and the radius of each removal region is R, so that “L = 2 × R”, and the odd-numbered and even-numbered scan lines are orthogonal to the scan direction and the scan direction. It is characterized in that the scanning is performed while being shifted by the radius R in each direction.

  According to this organic EL mask cleaning method, scanning is performed so as to satisfy the above formula. The removal regions constituting the odd-numbered scan lines and the even-numbered scan lines are formed so as to be in contact with each other in two directions, but the odd-numbered and even-numbered scan lines are arranged in the scan direction and the orthogonal direction. Therefore, no gap is generated. Further, the other removal region does not overlap the center of one removal region.

  The organic EL mask cleaning method according to claim 4 of the present invention is the organic EL mask cleaning method according to claim 3, wherein one of the odd-numbered scan lines and the even-numbered scan lines is scanned. After scanning all of the above, the other scan line is scanned, and the intensity of the laser light of the scan line to be scanned later is set lower than the scan line to be scanned first.

  According to this organic EL mask cleaning method, the scan lines in one of the odd-numbered columns and even-numbered columns are scanned, and then the scan lines in the other column are scanned. As a result, the vapor deposition material remains in part due to the scan line scanned earlier, but the adhesion strength is weak, so the vapor deposition material can be removed even if the laser light intensity in the next scan is weakened. Thereby, a high degree of cleaning can be obtained without applying excessive energy to the organic EL mask.

  According to a fifth aspect of the present invention, there is provided a program for causing a computer to execute the procedure of the organic EL mask cleaning method according to any one of the first to fourth aspects.

  The organic EL mask cleaning device according to a sixth aspect of the present invention is an organic EL mask cleaning device that removes vapor deposition substances adhering to the organic EL mask by scanning a laser beam, The removal region extends over the entire surface of the cleaning area by partially overlapping a laser scanning unit that intermittently scans the laser beam and a circular removal region of the vapor deposition material that is removed by irradiating the laser beam. And laser control means for controlling the laser scanning means so that the center of one removal area does not overlap with another removal area.

  The organic EL mask cleaning device according to a seventh aspect of the present invention is the organic EL mask cleaning device according to the sixth aspect, wherein the laser control means is arranged so that the plurality of removal regions are arranged in one direction. When scanning is performed by shifting the scanned scan line in a direction perpendicular to the scan direction, the interval between the centers of two adjacent removal regions in the scan line and the shift amount of the scan line are set to L, The laser scanning unit is controlled so that “R <L ≦ √2 × R” when the radius is R.

  An organic EL mask cleaning apparatus according to an eighth aspect of the present invention is the organic EL mask cleaning apparatus according to the sixth aspect, wherein the laser control means is configured so that the plurality of removal regions are arranged in one direction. When scanning is performed by shifting the scanned scan line in a direction orthogonal to the scan direction, the interval between the centers of two adjacent removal regions in each scan line, the interval between odd-numbered scan lines, and the even-numbered column Scan the odd-numbered and even-numbered scan lines so that “L = 2 × R” where L is the interval between the scan lines and R is the radius of each removal region. The laser scanning means is controlled so as to be shifted by the radius R in the direction perpendicular to the direction and the scanning direction.

  An organic EL mask cleaning apparatus according to a ninth aspect of the present invention is the organic EL mask cleaning apparatus according to the eighth aspect, wherein the laser control means includes an odd-numbered scan line and an even-numbered scan line. One of the scan lines is scanned, then the other scan line is scanned, and the intensity of the laser beam of the scan line scanned after the first scan line is set lower.

  An organic EL display manufacturing apparatus according to a tenth aspect of the present invention includes the organic EL mask cleaning apparatus according to any one of the sixth to ninth aspects. An organic EL display according to an eleventh aspect of the present invention is manufactured by the organic EL display manufacturing apparatus according to the tenth aspect.

  In the present invention, the organic EL mask is irradiated with laser light to remove the vapor deposition material so that the circular removal region covers the entire surface of the area to be cleaned, and another removal region is provided at the center of one removal region. Since the scanning of the laser beam is performed so that the regions do not overlap, a high degree of cleaning can be obtained without applying excessive energy that causes deformation or the like to the organic EL mask. .

It is an external view of the mask cleaning apparatus for organic EL. It is the side view and top view of the organic EL mask which were made to contact | abut to the glass substrate. It is a block diagram of a light source control part, and a hardware block diagram at the time of implement | achieving a laser control part with a computer. It is a figure explaining the relationship of the removal area | region in 1st scanning mode. It is a figure explaining the relationship of the removal area | region in 2nd scanning mode.

  Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, an organic EL mask cleaning device (device for laser cleaning the surface of an organic EL mask with laser light) of the present invention includes a base 1, an organic EL mask 2, a mask holding member 3, and laser scanning means 4. It has a schematic configuration. The base 1 is a base for mounting each element of the organic EL mask cleaning device. Here, in FIG. 1, the X direction and the Y direction are two directions orthogonal to each other on the horizontal plane, and the Z direction is a vertical direction. The direction indicated by the arrow in the Z direction is upward, and the opposite side is downward. Therefore, gravity acts in the opposite direction of the arrow.

  The organic EL mask 2 is an object to be cleaned that is cleaned using an organic EL mask cleaning device. As shown in FIG. 2, the organic EL mask 2 is an ultra-thin metal plate used for patterning by depositing an organic material (evaporation substance) as a light emitting layer on a glass substrate 20 constituting an organic EL display. It is. In order to deposit a vapor deposition substance on the glass substrate 20 with high accuracy, the thickness of the organic EL mask 2 is a very thin metal plate on the order of microns. As the size of the organic EL display is increased, the size of the organic EL mask 2 is also increased. For this reason, the organic EL mask 2 is an extremely thin and large metal plate.

  The organic EL mask 2 has a mask body 21 and is a mask metal plate (shadow mask) in which a large number of openings 22 regularly arranged in the mask body 21 are formed. Various materials can be used as the material of the organic EL mask 2, but an alloy of cobalt and nickel is applied here. The organic EL mask 2 is made to deposit an organic material from a deposition source in a state of being in close contact with the glass substrate 20 in a vacuum deposition tank (not shown) for depositing the organic material of the light emitting layer.

  Various materials can be used as the evaporating material for the light emitting layer. For example, an organometallic complex such as an aluminum complex (trisaluminum: Alq) is used. Note that an organic compound other than the organometallic complex (which may or may not contain a metal) may be applied as a vapor deposition substance. The vapor deposition material evaporated from the vapor deposition source is deposited on the glass substrate 20 through the opening 22 of the organic EL mask 2. As a result, the vapor deposition material as the light emitting layer is deposited on the region corresponding to the pixel of the glass substrate 20 to form a pattern. Since the organic EL mask 2 is a large and extremely thin metal plate, as shown in FIG. 2, a reinforcing frame 23 is attached around the periphery thereof to provide shape retention. The reinforcing frame 23 may be a metal material or a material other than metal.

  When the vapor deposition process is performed once using the organic EL mask 2, the vapor deposition material adheres not only to the glass substrate 20 but also to the organic EL mask 2. Since the vapor deposition process is repeated, cleaning of the vapor deposition material adhering to the organic EL mask 2 is performed at a predetermined timing (preferably for each vapor deposition process). Since the cleaning tank in which the organic EL mask cleaning device is disposed and the vacuum deposition tank for vapor deposition on the glass substrate 20 are provided separately and independently, the organic EL mask 2 is used when performing the organic EL mask cleaning device. It is transferred from the vacuum deposition tank to the cleaning tank.

  As shown in FIG. 1, the organic EL mask 2 is held in a vertical state (the normal direction of the surface of the organic EL mask 2 is the horizontal plane direction). For this reason, the mask holding member 3 has the same size as or larger than the size of the organic EL mask 2, and a large number of magnets (not shown) are arranged on the mask holding member 3 (for example, in a lattice shape). Regularly arranged). As a result, the organic EL mask 2 can be held upright. If the magnets are regularly arranged in a lattice pattern, the organic EL mask 2 can be held uniformly and the planarity of the organic EL mask 2 is improved.

  Here, the organic EL mask 2 is sucked and held by magnetic force, but may be held by another holding means such as a vacuum suction means. The organic EL mask 2 may be held in a laid state (the normal direction of the surface of the organic EL mask 2 is vertical). In this case, means such as a magnet and vacuum suction are not necessary.

  Returning to FIG. 1, the laser scanning means 4 will be described. The laser scanning unit 4 includes a laser light source 41, a galvano mirror 42, and a galvano driving unit 43, and is schematically configured. The laser light source 41 is a light source that oscillates laser light.

  The laser light source 41 is arranged so that laser light is oscillated downward in the Z direction, and a galvano mirror 42 is arranged at the incident position of the laser light. The galvano mirror 42 is a reflection mirror that scans the surface of the organic EL mask 2 with laser light, and the reflection direction of the laser light changes by minutely vibrating the mirror at high speed. Thereby, the laser beam is scanned. Laser light scanning is performed on a predetermined area (cleaning area) of the organic EL mask 2. Therefore, the laser beam is scanned in the X direction to form one scan line, and the area (surface) is scanned by finely shifting the scan line in the Z direction. When the cleaning area is set on the entire surface of the organic EL mask 2, the entire surface is cleaned, but may be set on a part of the area.

  A galvano driving unit 43 is attached to the galvano mirror 42, and the galvano driving unit 43 vibrates the galvano mirror 42. The laser light source 41, the galvanometer mirror 42, and the galvano drive unit 43 constitute a laser scanning unit. The laser controller 50 shown in FIG. 3 controls the laser scanning means.

  The laser control unit 50 is a laser control unit, and includes a light source control unit 51, a galvano control unit 52, and a setting unit 53. The light source control unit 51 controls the laser light source 41. The laser light source 41 is a pulse laser that oscillates laser light in synchronization with a pulse having a very short time width (for example, nano-order or less). That is, it becomes intermittent irradiation which repeats an oscillation state and a stop state. By making the laser light source 41 a pulse laser, the energy of the laser light can be concentrated and a high peak can be obtained. The light source controller 51 outputs pulse width data to the laser light source 41, and the laser light source 41 oscillates laser light based on the pulse width. Further, the light source control unit 51 controls the oscillation intensity of the laser light source 41 so that the laser beam can be oscillated with an arbitrary oscillation intensity.

  The galvano control unit 52 controls the galvano drive unit 43. The data of the vibration amount of the galvano mirror 42 is output from the galvano control unit 52 to the galvano driving unit 43, and the galvano driving unit 43 vibrates the galvano mirror 42 based on the data. This is data including a vibration amount for vibrating the galvanometer mirror 42 during the time of the pulse width, a vibration amount for vibrating when the scan line is changed, and the like. The galvano control unit 52 controls the galvano drive unit 43 to scan the laser beam. The galvano drive unit 43 receives pulse width data from the light source control unit 51.

  The setting unit 53 is connected to the light source control unit 51 and the galvano control unit 52. The light source control unit 51 outputs oscillation intensity data, and the galvano drive unit 43 outputs scan mode data. Based on the oscillation intensity data output from the setting unit 53, the light source control unit 51 adjusts the oscillation intensity of the laser light source 41. As will be described later, there are two scanning modes for laser light scanning, and the vibration control of the galvano mirror 42 differs depending on which scanning mode is selected. Therefore, scan mode data is output from the setting unit 53 to the galvano control unit 52. If the oscillation intensity can be set directly for the light source control unit 51 and the scanning mode can be set directly for the galvano drive unit 43, the setting unit 53 need not be provided.

  FIG. 3B is a hardware block diagram when the contents of the laser control unit 50 are realized by a computer, and includes a CPU 54, a memory 55, a storage unit 56, an input unit 57, an output unit 58, and a bus 59. The schematic configuration. The CPU 54 executes a program in which the control content of the laser control unit 50 is stored, and the memory 55 temporarily stores the program. The storage unit 56 stores other necessary data, and the input unit 57 is a means by which various setting contents can be manually input. For example, a scanning mode can be selected. The output unit 58 is an interface connected to the laser light source 41 and the galvano drive unit 43, and outputs various data to each.

  Returning to FIG. 1, the conveying air flow forming means 6 will be described. The carrier air flow forming means 6 includes a blower unit 61 and an air suction unit 62 and is schematically configured. The blower 61 is attached to a blower support 63 consisting of two struts extending in the Y direction, and the air suction part 62 is also attached to a wind suction support 64 consisting of two struts extending in the Y direction. Yes. Further, the air blowing support portion 63 and the air suction support portion 64 are each attached to the base 1. The air suction part 62 is provided with a recovery part 65, and the recovery part 65 recovers the sucked free substance.

  The blower 61 is formed with a blow slit 61S having a long slit length and a short slit width. Similarly, a wind absorption slit 62S having a long slit length and a short slit width is also formed in the wind absorption portion 62. The air blowing slit 61S and the air suction slit 62S are formed so as to face the same position in the Y direction, and are formed at positions separated from the surface of the organic EL mask 2. Air is blown downward from the blower slit 61 </ b> S, and the air suction slit 62 </ b> S sucks the upper air, so that an air flow is formed between the blower 61 and the air sucker 62. This air flow is referred to as a carrier air flow. In addition, although the conveyance airflow is formed by the slit provided in the ventilation part 61 and the air suction part 62, you may employ | adopt mechanisms other than a slit.

  The mask moving means 7 will be described. The mask moving means 7 is a moving means for moving the organic EL mask 2, and is schematically constituted by a moving table 71. The moving table 71 is a table for fixing and moving the mask holding member 3 in a vertical state. As the moving table 71, for example, a ball screw means, a linear motor means, a robot means or the like can be applied. As the moving table 71 moves, the organic EL mask 2 moves in a vertical state. Although the movement table 71 shows an example of moving in the X direction, it may be movable in the Y direction and the Z direction.

  Next, the operation will be described. In the present invention, there are two laser beam scanning modes, and the setting unit 53 sets in advance which scanning mode is used. Details of this scanning mode will be described later.

  First, after depositing vapor deposition material on the glass substrate 20 using the organic EL mask 2 in a vacuum vapor deposition tank (not shown), the organic EL mask 2 is carried into the organic EL mask cleaning device disposed in the cleaning tank. . At the time of carry-in, the organic EL mask 2 is held in contact with the mask holding member 3 and is held upright. In this state, the moving table 71 moves the organic EL mask 2 to the position of the carrier air flow forming means 6 in the X direction and stops at that position.

  Cleaning is started with the organic EL mask 2 stopped. This cleaning is performed by irradiating the organic EL mask 2 with laser light. This cleaning is laser cleaning. Here, laser cleaning will be described. The laser cleaning is cleaning that irradiates the organic EL mask 2 with laser light in order to remove the vapor deposition material adhering to the organic EL mask 2. The organic EL mask 2 is disposed such that the surface (front surface) to which the vapor deposition material is attached faces the direction of laser light irradiation, and the laser light reflected by the galvano mirror 42 is irradiated to the organic EL mask 2. .

  When the organic EL mask 2 is irradiated with the laser light, a thermal shock is given to the organic EL mask 2 by the energy of the laser light, or the vapor deposition material adhering to the organic EL mask 2 is instantaneously vaporized at a high temperature. Removed. The removed vapor deposition material is separated from the organic EL mask 2 as a free material such as very fine powder or gas. Although the mass of free material is very small, gravity acts. Therefore, the free substance separated from the organic EL mask 2 falls due to gravity. In the direction away from the organic EL mask 2, a conveying air flow is formed by the air blowing unit 61 and the air sucking unit 62, and the separated free substance is captured by the carrier air flow to the air sucking unit 62. It will be transported. Thereby, the free substance separated from the organic EL mask 2 does not reattach to the organic EL mask 2.

  By irradiating the organic EL mask 2 with laser light, the vapor deposition material is partially removed by thermal shock or high temperature vaporization. The cross section of the optical path of the laser light is circular, and the laser light is incident from the normal direction of the organic EL mask 2, so that the region where the vapor deposition material is removed is also circular. This circular area (removed area) may coincide with the spot diameter of the spot formed when the laser beam is irradiated on the organic EL mask 2, and if it is larger than the spot diameter, it will be smaller than the spot diameter. Sometimes it becomes. However, in any case, the region where the vapor deposition material is removed by irradiating the laser beam becomes circular. Note that the removal region may be substantially circular as long as it is not completely circular. For example, an ellipse having almost no difference between the major axis and the minor axis is also included in the removal region.

  The laser light oscillated from the laser light source 41 is a pulse laser, and the laser light is oscillated in synchronization with a pulse having a very short time width. Then, by oscillating the galvanometer mirror 42 and changing the reflection angle at high speed, a large number of circular removal regions are formed in the organic EL mask 2 at minute pitch intervals.

  Then, the laser beam is scanned in one direction (X direction) to form a scan line, and this scan line is finely shifted in a direction (Z direction) perpendicular to the scan direction, thereby scanning the surface. Do. In other words, one scan line is formed by a large number of circular removal regions arranged in a line at a minute pitch interval, and the scan of the surface is performed by minutely shifting the scan line by the collection of the removal regions in the Z direction.

  In this case, the setting of the interval of the removal region and the scanning method are different between the first scanning mode and the second scanning mode. In the first scanning mode, as shown in FIG. 4, adjacent removal regions (shown as RA in the drawing) in one scan line partially overlap with each other, and removal regions in adjacent scan lines Scanning is performed so that they partially overlap each other. At this time, when there are few overlapping regions of the removal regions, a gap is generated between the removal regions, but the gap is not generated by increasing the area of the overlapping portion to some extent. As a result, the laser beam is irradiated over the entire area to be scanned.

  Then, scanning is performed so that the center of each removal region and the adjacent removal region do not overlap. The intensity distribution of the laser beam is Gaussian, and the intensity at the center is the highest in the entire circular removal region. Therefore, strong energy acts on the organic EL mask 2 at the center of the removal region. For this reason, when another removal region overlaps the center of one removal region, energy further acts on a point (removal region center) where strong energy originally acts. Thereby, excessive energy acts on the organic EL mask 2 (a certain point). Accordingly, by not including the center in the portion where the removal region and the removal region overlap, excessive energy is prevented from acting on the organic EL mask 2.

  The laser beam is scanned so that a large number of removal regions are formed at intervals that satisfy the above conditions. At this time, when the radius of the removal area is “R”, the distance between the centers of the adjacent removal areas and the shift amount of the scan line are “L”, “R <L ≦ √2 × R”. Take control. As shown in FIG. 4, a large number of removal regions are arranged in the X direction and the Z direction, and in order to prevent the center from being included in the interval L between the removal regions in one scan line, “R < L ”. At the same time, in order not to include the center in the Z direction, the shift amount is set to the same L, and “R <L”.

  Then, “L ≦ √2 × R” is set so that the removal region covers the entire surface of the cleaning area. A gap is formed between the circular removal regions because the distance (center) between the centers of the removal regions (removal regions adjacent to each other in the oblique direction) separated by one in the X direction and the Z direction is the diameter of the removal region. Therefore, it is necessary to satisfy “M ≦ 2 × R”. At this time, the distance between the centers of the removal regions adjacent to each other in the X direction and the Z direction is L, and the relationship between M and L is “M = √2 × L”. Therefore, in order to satisfy “M ≦ 2 × R”, the relationship between L and R needs to be “L ≦ √2 × R”. By satisfying this condition, there is no gap between the removal region and the removal region.

  Therefore, the laser beam is scanned so that “R <L ≦ √2 × R”. The galvano controller 52 of the laser controller 50 controls the galvano controller 52 so as to satisfy this condition. The radius R of the removal region is known. When it matches the spot diameter of the laser beam, R is the spot diameter of the laser beam. Even if they do not match, the radius R can be obtained from the intensity of the laser beam, the material of the vapor deposition material, the material of the organic EL mask 2, and the like. The L is a change amount of the irradiation position of the laser beam that is changed during one pulse. That is, the laser light is irradiated to a certain position with one pulse, and the laser light is irradiated to the next position with the next pulse, and a large number of removal regions are formed in the organic EL mask 2. The amount of change in the irradiation position of the laser beam that has changed to L is the above-mentioned L.

  For this purpose, the galvano control unit 52 receives data of one pulse width (one pulse time) from the light source control unit 51, and how much the galvano drive unit 43 is vibrated during this one pulse to thereby generate laser light. The amount of vibration for changing the irradiation position is determined. Then, based on the determined vibration amount, the galvano drive unit 43 vibrates the galvano mirror 42. Thereby, the distance L between the centers of the removal regions can be controlled. As described above, since the radius R of the removal region is known, the galvanometer mirror 42 is vibrated so that the distance L satisfies “R <L ≦ √2 × R”. Similarly, when shifting from one scan line to the next scan line, the shift amount to be slightly shifted in the Z direction is also L, that is, a shift that satisfies “R <L ≦ √2 × R”. Set to quantity.

  By performing the laser beam scanning so as to satisfy the above formula, it becomes possible to exert a laser beam removal region over the entire area to be scanned, and it is excessive with respect to the organic EL mask 2. Energy stops working.

  Next, the second scanning mode will be described. As described above, the cleaning area is cleaned by shifting the scan lines in the Z direction. In the second scan mode, each scan line is grouped into odd-numbered scan lines and even-numbered scan lines. Divide. First, all odd-numbered scan lines are scanned, and then all even-numbered scan lines are scanned. Of course, the odd-numbered columns may be operated after scanning the even-numbered columns first. Therefore, in the second scanning mode, the cleaning area is scanned twice. In FIG. 5, the removal region of the odd-numbered scan lines is indicated by a solid line, and the removal region of the even-numbered scan lines is indicated by a virtual line.

  In the first scan (scan of odd-numbered scan lines), the laser beam is scanned so that each removal region is in contact with an adjacent removal region. That is, as in the case described above, when the radius of the removal area is “R” and the distance between the centers of the adjacent removal areas is “L”, the first scan is “L = 2 × R”. Do as follows. For this purpose, the galvano control unit 52 receives pulse width data from the light source control unit 51, and the galvano drive unit 43 so that the irradiation position of the laser beam changes by “L = 2 × R” during one pulse. To control. Then, one scan line is formed, and the scan line is slightly shifted in the Z direction. The shift amount at this time is also shifted so as to be “L = 2 × R”.

  Laser light is scanned over the entire surface of the cleaning area by the first scanning. However, in the first scan, there is a portion where the laser beam is not irradiated between the removal region and the removal region. This is because the removal area is circular, and therefore a gap is always generated when the removal areas are arranged in contact with each other. Therefore, a second scan (scan of even-numbered scan lines) is performed.

  The second scan is performed from a position shifted by the radius R in the X direction and the Z direction from the position where the first scan was performed. That is, the removal region formed by the first scan and the removal region formed by the second scan are shifted by the radius R in two directions (X direction and Z direction) orthogonal to each other. become. Therefore, the scan line to be formed first starts scanning from the position shifted by the radius R in the X direction and Z direction from the scan line formed first in the first scan. Then, the scan line is gradually shifted in the Z direction. This shift amount is also L, and “L = 2 × R”. Then, the entire surface of the cleaning area is scanned.

  As shown in FIG. 5, the gap generated by the first scan is completely covered by the second scan. That is, the laser beam is irradiated so as to cover the entire area to be cleaned by the first and second scans. In the first time and the second time, scanning is performed from a position shifted by the radius R in the X direction and the Z direction (because the reference position for starting scanning is shifted), the center of one removal region And other removal regions do not overlap. Therefore, the cleaning can be performed with a high degree of cleaning, and the organic EL mask 2 is not excessively damaged.

  Note that scanning of all scan lines in odd columns is performed as the first scan, and scanning of all scan lines in even columns is performed as the second scan. The scanning of the scan line in the column may be alternately performed to perform one scanning. In this case, every time scanning of one scan line is finished, it is shifted by the radius R in the X direction and the Z direction. Further, as described later, when there is a difference in strength, the strength is changed each time.

  Although the scanning mode differs between the first scanning mode and the second scanning mode, basically, the entire surface of the cleaning area is irradiated with laser light, and the center of one removal region is the other. This prevents the removal regions from overlapping each other. Therefore, there is no particular difference between the first scanning mode and the second scanning mode. However, the second scanning mode has an advantage that damage to the organic EL mask 2 can be reduced as compared with the first scanning mode.

  In the second scanning mode, the entire area to be cleaned is scanned twice. The gap generated by the first scan becomes a region surrounded by four circular removal regions, and the region is an independent region divided by each removal region formed by the first scan (each of the four circles 1 / A region formed by four rounds: hereinafter, a remaining region). Therefore, the remaining regions are arranged in a matrix in the X direction and the Z direction. In the second scan, the laser beam is scanned so as to include the remaining region.

  Since the surrounding vapor deposition material is removed from each remaining region and is divided, the adhesion strength of the vapor deposition material in the remaining region is greatly weakened by the first scanning. Therefore, even if the laser beam used for the second scan has a lower intensity than the laser beam used for the first scan, the vapor deposition material in the remaining region can be sufficiently removed. Therefore, the light source control unit 51 controls the oscillation intensity of the laser light source 41 to be lower in the second time than in the first time. As a result, the intensity of the laser beam in the second scanning can be lowered, and the energy acting on the organic EL mask 2 can be reduced. However, since a certain amount of adhesion strength remains in the vapor deposition material in the remaining region, the laser beam at the time of the second scanning should have an oscillation intensity that can be removed.

  In addition, although a certain amount of time is required to switch the oscillation intensity of the laser light source 41, since the number of scans is divided into two in the second scanning mode, it is possible to provide a sufficient switching time. That is, the first scan is performed over the entire cleaning area, and then the second scan is performed over the entire area. Therefore, since there is some time margin when switching between the first scan and the second scan, the oscillation intensity of the laser light source 41 can be switched at this time.

2 Organic EL Mask 4 Laser Scanning Means 41 Laser Light Source 42 Galvano Mirror 43 Galvano Drive Unit 50 Laser Control Unit 51 Light Source Control Unit 52 Galvano Drive Unit 52 Galvano Control Unit 53 Setting Unit

Claims (11)

An organic EL mask cleaning method for scanning a laser beam to remove a vapor deposition material adhering to the organic EL mask,
When the organic EL mask is scanned by intermittently irradiating the laser beam, a circular removal region of the vapor deposition material removed by irradiating the laser beam is partially overlapped. An organic EL mask cleaning method, characterized in that scanning is performed so that the removal region extends over the entire surface of the cleaning area, and the center of one removal region does not overlap another removal region. When scanning is performed by shifting a scan line scanned so that a plurality of the removal regions are arranged in one direction in a direction perpendicular to the scan direction,
When the interval between the centers of two adjacent removal regions in the scan line and the shift amount of the scan line are L, and the radius of each removal region is R,
The organic EL mask cleaning method according to claim 1, wherein scanning is performed such that “R <L ≦ √2 × R”. When performing scanning by shifting a scan line scanned so that a plurality of the removal regions are arranged in one direction in a direction perpendicular to the scanning direction,
When the distance between the centers of two adjacent removal areas in each scan line, the distance between the odd-numbered scan lines and the distance between the even-numbered scan lines are L, and the radius of each removal area is R. The scanning is performed by shifting the odd-numbered scan lines and the even-numbered scan lines by the radius R in the scan direction and the direction orthogonal to the scan direction so that “L = 2 × R”. The organic EL mask cleaning method according to claim 1. After scanning one scan line of all of the odd-numbered scan lines and even-numbered scan lines, the other scan line is scanned,
4. The organic EL mask cleaning method according to claim 3, wherein the intensity of the laser beam of the scan line scanned after the first scan line is set lower.   The program for making a computer perform the procedure of the mask cleaning method for organic EL of any one of Claims 1 thru | or 4. An organic EL mask cleaning device that scans a laser beam to remove a vapor deposition material attached to the organic EL mask.
Laser scanning means for intermittently scanning the laser light on the organic EL mask;
The removal region extends over the entire surface of the cleaning area by partially overlapping a circular removal region of the vapor deposition material that is removed by irradiating the laser beam, and the center of one removal region and another Laser control means for controlling the laser scanning means so as not to overlap the removal region;
An organic EL mask cleaning device comprising: The laser control means includes
The interval between the centers of two adjacent removal regions in the scan line when scanning is performed by shifting a scan line scanned so that the plurality of removal regions are arranged in one direction in a direction orthogonal to the scan direction. The laser scanning unit is controlled so that “R <L ≦ √2 × R” where L is the shift amount of the scan line and R is the radius of each removal region. Item 7. The organic EL mask cleaning device according to Item 6. The laser control means includes
The distance between the centers of two adjacent removal regions in each scan line when scanning is performed by shifting a scan line scanned so that the plurality of removal regions are arranged in one direction in a direction perpendicular to the scan direction. When the distance between the scan lines in the odd-numbered columns and the distance between the scan lines in the even-numbered columns is L, and the radius of each removal region is R, “L = 2 × R” and the odd-numbered columns 7. The laser scanning unit is controlled so that the scan line of the eye and the scan line of the even-numbered column are shifted by a radius R in a scan direction and a direction orthogonal to the scan direction, respectively. Organic EL mask cleaning device. The laser control means scans one of the odd-numbered scan lines and the even-numbered scan lines, and then scans the other scan line, and then scans after the first scan line. 9. The organic EL mask cleaning device according to claim 8, wherein the intensity of the laser beam of the scan line to be scanned is set low.   An organic EL display manufacturing apparatus comprising the organic EL mask cleaning apparatus according to claim 6.   An organic EL display manufactured by the apparatus for manufacturing an organic EL display according to claim 10.

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