MXPA01001275A - Apparatus and method for developing a latent charge image - Google Patents

Abstract

The invention includes an apparatus (40, 140) for developing a latent charge image formed on a photoreceptor (36) disposed on an interior surface of a faceplate panel (12). The apparatus (40, 140) comprises a developer tank (42) having a sidewall (44) closed at one end by a bottom portion (46) and at the other end by a panel support (48) having an opening (50) therethrough to provide access to the faceplate panel (12). The back electrode (52) has a potential applied thereto to establish an electrostatic drift field between the back electrode and the photoreceptor (36), which is grounded. Triboelectrically-charged, dry-powdered, light emitting phosphor material, having a charge of the same polarity as the potential applied to the back electrode (52), is injected into the developer tank (42), between the back electrode (52) and the faceplate panel (12). The triboelectrically charged phosphor material is directed toward the photoreceptor (36) on the faceplate panel (12) by the applied electrostatic drift field. Panel skirt sidewall shields (66, 68) are disposed around a peripheral sidewall (18) of the faceplate panel (12) to repel the triboelectrically-charged phosphor material from the panel sidewall (18).

Description

APPARATUS AND METHOD FOR DEVELOPING A LATENT LOAD IMAGE FIELD OF THE INVENTION The invention relates to an apparatus and method for developing a latent charge image in a photoreceptor disposed on the inner surface of a cover plate of a cathode ray tube (CRT) and more particularly to an apparatus that it has a lower electrode and a side wall cover and a method for operating an apparatus for revealing with the lower electrode and the cover.

BACKGROUND OF THE INVENTION An apparatus for developing a latent charge image on a photoreceptor that is disposed on the inner surface of a cover plate of a deployment device, such as a cathode ray tube (CRT), which utilizes charged particles triboelectrically, it is described in U.S. Patent No. 5,477,285, published December 19, 1995, to GHN Riddie et. to the. In one embodiment of the apparatus for developing, a developing chamber is described having insulating side walls and an insulating board support. A triboelectric gun having a rotating nozzle system directs a mixture of air and phosphorus charged particles, dried into the developing chamber, where the phosphor collides with the walls of the surrounding chamber. The phosphorus-charged particles create a build-up of charge in the insulating side walls of the developer and in the insulating cover which prevents the deposition of phosphorus on the side of the board of the cover plate, in a revealing grid, more widely described in the patent. No. 5,093,217, issued to Datta et. al., March 3, 1992. It is necessary to frequently clean the internal components of the developer to eliminate the accumulation of phosphorus before it is released and deposited on the photoreceptor in an uncontrolled manner. Additionally, after impact with the internal surfaces of the developer, the displaced phosphor particles approach the photoreceptor by virtue of the uncontrolled repulsion of the loading space. This impact produces agglomerates having a load and a defined deteriorated mass, which could cause the phosphor particles to settle in undesired places in the photoreceptor provided on the inner surface of the cover plate board. This results in the combination of different colored phosphor lines formed in the photoreceptor. There is a need for a developer that effectively reduces the accumulation of phosphorus in its interior elements to reduce the cleaning frequency, minimize the disadvantages described above and provide a more uniform phosphor deposition in the photoreceptor, with greater control over the DEPOSITION PROCESS BRIEF DESCRIPTION OF THE INVENTION In accordance with the present invention, an apparatus and a method for developing a latent electrostatic charge image that is formed in a photoreceptor that is disposed on the inner surface of a coating board board are disclosed. of a CRT. The apparatus comprises a developer tank having a side wall closed at one end by a lower portion and at the other end by a board support with an opening therethrough to provide access to the board. A rear electrode is located within the developer tank and is separate from, but parallel to, the interior surface of the cover plate board. The rear electrode has a first potential applied to it to establish an electrostatic displacement field between the rear electrode and the photoreceptor that is grounded. The triboelectrically charged, dry powder, light-emitting phosphor materials having a charge of the same polarity as the first potential applied to the back electrode are introduced into the developer tank between the back electrode and the cover plate board. The phosphorus materials triboelectrically charged, they are directed towards the photoreceptor on the cover plate board by the applied electrostatic displacement field. A sidewall cover of the side of the board is disposed around the peripheral side wall of the cover plate board to repel the phosphor materials triboelectrostically charged from the side wall of the board. The method for developing a latent charge image formed in a photoreceptor disposed on an inner surface of a covering board of a CRT, includes the steps of placing the cover plate board in the apparatus; place the cover of the side wall of the side of the board near the side wall of the board; grounding the photoreceptor; apply a first potential to the rear electrode and introduce it inside the developer tank, between the rear electrode and the cover plate board, the triboelectrically charged phosphor materials have the same polarity as the first potential applied to the rear electrode, so the materials of phosphorus are directed towards the photoreceptor on the cover plate board by the applied electrostatic displacement field.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: Figure 1 is a plan view, partially in axial section, of a color CRT made in accordance with the present method; Figure 2 is a section of the cover plate board with a structure on an interior surface thereof during a step of the manufacturing process; Figure 3 is a section of the full screen unit of the tube shown in Figure 1; Figure 4 is a section of the cover plate board of the CRT showing a photoreceptor that is superimposed on the structure during another step of the manufacturing process; Figure 5 shows the first embodiment of the disclosure apparatus used in the present invention; Figure 6 is an enlarged section of the cover plate board of the CRT and the cover shown within the circle 6 of Figure 5; and Figure 7 shows the second embodiment of the apparatus for revealing.

DETAILED DESCRIPTION OF THE PREFERRED MODALITY Figure 1 shows a color CRT 10 having a cover 11 glass, which comprises a rectangular cover plate board 12 and a tubular neck 14 connected by a funnel 15. The funnel 15 has an internal conductive coating (not shown) which contacts the button 16 of the anode and extends inside the neck 14. The board 12 comprises a cover plate 17 for display and a side wall 18 or peripheral flange, which is sealed with the funnel 15 by a glass layer 19. As shown in Figure 2, a relatively thin, light-absorbing structure 20, having a plurality of openings 21, is provided on the inner surface of the display cover plate 17. A luminescence three-color phosphor screen 22 is carried on the inner surface of the cover plate 17 and is superimposed on the structure 20. The screen 22, shown in Figure 3, is preferably a line screen. which includes a multiplicity of screen elements composed of green, blue and red emitting phosphor bands R, B and G, centered on the different openings 21 of the structure and configured in color groups or three-band or three-dimensional picture elements , in a cyclical order. The bands extend in a direction that is generally normal to the plane in which the electron beams are generated. In the normal mode display position, the phosphor bands extend in the vertical direction. Preferably, the portions of the phosphor bands are superimposed on at least a portion of the absorbent structure 20 surrounding the openings 21. Alternatively, a dot screen may be used. A thin conductive layer 24, preferably aluminum, is superimposed on the screen 22 and provides a means to apply a uniform potential on the screen, as well as to reflect the light emitted from the phosphor elements, through the plate Coating 17. The screen 22 and the overlay aluminum layer 24 comprise a screen unit. Again, with reference to Figure 1, a color selection electrode with multiple apertures, such as a shadow mask, a tension mask or a focus mask, electrode 25 is removably mounted by a conventional means, in a ratio Separate default of the display unit. The color selection electrode 25 is releasably coupled with a plurality of uprights 26 embedded in the side wall 18 of the board 12, in a manner known in the art. An electron gun 27, shown schematically by dashed lines, is mounted centrally within the neck 14, to generate and direct three electron beams 28 along converging paths, through the openings in the electrode 25 for selecting the electron. color to the screen 22. The electron gun is conventional and can be any gun known in the art. The tube 10 is designed to be used with an external magnetic deflection fork, as a fork 30, located in the region of the junction of funnel to neck. When activated, the fork 30 subjects the three beams 28 to magnetic fields, which causes the rays to explode vertically and horizontally, in a rectangular tracker on the screen 22. The initial deflection plane (at zero deflection) is shown by the line PP in Figure 1, approximately halfway through the fork 30. For reasons of simplification, the actual curvatures of the deflection paths of the rays in the deflection zone are not shown. The screen 22 is manufactured by an electrophotographic screened (EPS) process which is described in U.S. Patent No. 4,921,767 issued to Datta et. al., May 1, 1990.

Initially, the board 12 is cleaned by being washed with a caustic solution, rinsed in water, etched in strong water with hydrofluoric acid buffer and rinsed again with water, as is known in the art. The interior surface of the display cover plate 17 is then provided with a light absorbing structure 20, preferably, using the conventional wet structure process described in U.S. Patent No. 3,558,310, issued to Mayaud on May 26. January 1971. In the wet structure process, a suitable photoresist solution is applied to the interior surface, for example, by spiral coating and the solution is dried to form a photoresist layer. Then, the color selection electrode 25 is inserted into the board 12 and the board is placed on a light box, three in one (not shown) which exposes the photoresist layer to actinic radiation from a light source, which projects the light through the openings in the color selection electrode. The exposure is repeated twice more with the light source located to simulate the paths of the electron beams from the three electron guns. The light selectively alters the solubility of the exposed areas of the photoresist layer. After a third exposure, the board is removed from the light box and the color selection electron is removed from the board. The photoresist layer is developed, using water, to remove the most soluble areas thereof, whereby it exposes the underlying inner surface of the display coating plate and leaves intact the less soluble, exposed areas of the photoresist layer. Next, a suitable solution of light absorbing material is uniformly provided on the inner surface of the cover plate board to cover the exposed portion of the display coating plate and the less soluble, retained areas of the photoresist layer. The layer of light absorbing material is dried and developed using a suitable solution which will dissolve and remove the retained portion of the photoresist layer and superimposed light absorbing material, which forms the openings 21 in the structure 20, which adheres to the inner surface of the display coating plate. For a board 12 having a diagonal dimension of 51 cm (structure 20 inches), the openings 21 formed in the structure 20 have a width of approximately 0.13 to 0.18 mm, and the opaque structure lines have a width of approximately 0.1 to 0.15 mm. The inner surface of the display coating plate 17 has the structure 20 thereon, and is then coated with a suitable layer of an organic, volatile conductive material (OC), not shown, which provides an electrode for the layer (OPC) organic photoconductor, volatile superimposed, also not shown. The OPC layer and the OC layer in combination, comprise a photoreceptor 36, shown in Figure 4. Materials suitable for an OC layer include certain quaternary ammonium polyelectrolytes described in U.S. Patent No. 5,370,952 issued to P. Datta et al. . al., December 6, 1994. Preferably, the OPC layer is formed by coating the OC layer with a solution containing polystyrene; an electron donor material, such as 1,4 d i (2,4-methylphenyl) 1,4-diphenylbutatriene (2,4-DMPBT); permissible electron materials, such as 2,4,7-trinitro-9-fluorene (TNF) and 2 ethylanthroquinone (2 EAQ); and a suitable solvent, such as toluene, xylene or a mixture of toluene and xylene. A surfactant, such as silicone U 7602 and a plasticizer, such as dioctyl phthalate (DOP), can also be added to the solution. Surfactant U 7602 is marketed by Union Carbide, Danbury, CT. The photoreceptor 36 is electrostatically charged in a uniform manner, using a corona discharge device (not shown), but described in U.S. Patent No. 5,519,217 issued May 21, 1996 to Wilbur et. al., which charges the photoreceptor 36 to a voltage in the range of about +200 to +700 volts. The color selection electrode 25 is then inserted into the board 12, which is placed over a light box (also not shown) and the positively charged OPC layer of the photoreceptor 36 is exposed, through the color selection electrode 25, to illuminate a tube of flashes of xenon or another source of light of sufficient intensity, like a mercury arc, arranged inside the light box. The light passing through the openings in the color selection electrode 25, at an angle identical to that of the electron beams of the electron gun of the tube, discharges the illuminated areas in the photoreceptor 36 and forms an image of latent load (not shown). The color selection electrode 25 is removed from the board 12 and the board is placed on a first phosphor developer apparatus 40, such as that shown in Figure 5. In a first embodiment of the present invention, the apparatus The phosphor developer comprises a developer tank 42 having a side wall 44 closed at one end by a lower portion 46 and at the upper end by a board support 48, preferably made from PLEXIGLÁS or other insulating material, having a opening 50 therethrough to provide access to the interior of the cover plate board 12. The side wall 44 and the bottom portion 46 of the developer tank 42 are made of an insulator such as PLEXIGLÁS, externally surrounded by a ground cover made of metal. A rear electrode 52 is disposed within the developer tank 42 and is approximately electrode 25 spaced 30 cm below the center of the interior surface of the cover plate board 12. A positive potential of approximately 25 to 30 kV electrode is applied to the rear electrode 52 and the organic conductor of the photoreceptor 36 is grounded. With a separation of 30 cm between the rear electrode 52 and the cover plate board 12, a displacement field of 1 kV / cm or 105 V / cm is established. The phosphor material, in the form of dry powder particles, of the desired color light emitter is dispersed from a phosphor feeder 54, for example by a borer, not shown, within a stream of air passing through the tube 56 inside a Venturi tube 58, where it is mixed with the phosphor particles. The phosphorus mixture with air passes through channels into a tube 60, which imparts a triboelectric charge to the phosphorus powder due to the contact between the phosphor particles and the inner surface of the tube 60. For example, to positively charge the material of phosphorus a polyethylene tube is used. The air-phosphorous mixture then passes through a three-way ball valve 62, which directs the mixture in one of two equal lengths of the polyethylene pipe 60. Each of the tubes 60 ends in a manifold tube, not shown, which has a series of flat profile outlet nozzles 64, of which only two are shown, which spray the air mixture with phosphorus in a direction parallel to the 52 rear electrode. To achieve a uniform deposition of phosphorus in the charge image formed in the photoreceptor 36, the phosphor particles are injected from the nozzles 64 of a manifold tube for approximately 60 seconds. Then, the ball valve 62 is turned over, and the phosphor particles are injected from the nozzles 64 of the other manifold tube during the same period. The phosphorus particles of the injected phosphorus material have a typical μ mobility of approximately 3x10"6 (m / s) / (V / m), and the displacement velocity characteristic v, of the phosphor particles in the displacement field is approximately 0.3 m / sec As the phosphor material is injected into the displacement space, near the rear electrode 52, typically within about 10 cm from the rear electrode, the phosphor particles move toward the photoreceptor 36 on the board 12 and arrive there in a fraction of a second To avoid deposition of the phosphor material in the inner side wall of the rectangular board 12, two pairs of covers 66 and 68 of the side wall of the side of the board are used to form a rectangular array The covers 66 are separated from the short sides of the side wall of the board, while the covers 68 are separated from the long sides of the board. lateral network of the board. The covers 66 and 68 are formed of an insulating material, such as nylon, and have a thickness of approximately 2.5 mm and a height of approximately 5 cm for a cover plate board with a diagonal dimension of approximately 51 cm. The pairs of covers 66 and 68 have a dielectric constant that is three times that of the vacuum. When the injection of triboelectrically charged phosphorus particles starts, the pairs of covers 66 and 68 will initially be impacted by certain phosphorus charged particles and will accumulate the charge before this charge neutralizes the normal component of the electric field and the subsequent phosphorus collection charge is stopped by the covers. The typical value for an EPS board deposit of 51 cm is ten microcoulombs, μC, of phosphorus charge. The initial cover deposit of 2μC is a significant fraction of the board deposit. In case the covers 66 and 68 are not cleaned between the successive boards deposits, with normal dry air, the load in the covers will be conserved by multiple deposits of phosphorus. However, the electrostatic conditions near the covers 66 and 68 are not constant. For example, when the deposition of the phosphor particles in the latent charge image is completed, the board 12 is discharged from the apparatus 40. In order to cooperate with the loading and unloading of the board, the covers move away from the inner side wall of the board. board, which changes the capacity between the loaded surface of covers 66 and 68 and that of the side wall to the board ground. Because covers 66 and 68 have a constant charge and since V = Q / C, where V is the capacitor voltage, Q is the stored charge, and C is the capacity of the covers, as capacity decreases, the local voltage on the roofs increases and these voltage changes can cause a lateral movement of the phosphor, or the migration of the load on the roofs. This can result in the displacement or removal of accumulated phosphorus from the roofs and the resulting deposition of unwanted phosphorus on the photoreceptor, leading to board defects. To prevent the accumulation of the phosphor particles in the covers 66 and 68, the covers are printed with positive ions before loading the board 12 in the developing apparatus 40. In order to prime the covers 66 and 68, a ground plate or a board coated with only one OC layer is placed in the developer and the positive ions are injected from the nozzles 64 into the travel space between the rear electrode 52 and board 12. Positive ions will be deposited on decks 66 and 68 and will override the normal component of the electric field in the deck, so that in the subsequent phosphor deposition process, the decks do not attract and accumulate the charged phosphor particles. positively An alternative measure to inject positive ions into the displacement space is to ionize the air in the displacement space. This can be achieved, for example by ionizing radiation. When the air in the displacement space is ionized, preferably in the region near the positive back electrode 52, the negative ions will be collected by the positively charged back electrode and the positive ions will be displaced to a grounding plate board. Positive ions will also be attracted to covers 66 and 68 to ground. One method to significantly reduce changes in the capacity of the covers 66 and 68, when the covers move away from the inner side wall of the board during loading and unloading of the board 12 of the developing apparatus 40, is to provide a plate 70. to ground, shown in Figure 6, on the surfaces facing the side or rear wall of the covers 66 and 68. The capacity of the system formed by the plate 70 to ground and the covers 66 and 68 loaded does not change during the movement of the cover and therefore, does not change the local voltage on the covers. In this way, the lateral movement of phosphorus in the covers 66 and 68 is significantly reduced. Figure 7 shows a second embodiment of a developer 140. In this mode, the same numbers are used to indicate the elements identical to those of the first modality. The developer 140 comprises a developer tank 42 having a side wall 44 closed at one end by a lower portion 46 and at the upper end by a support 48 of the board, preferably made of PLEXIGLÁS or other insulating material, having an opening 50 therethrough to provide access to the inside of the cover plate board 12. The side wall 44 and the bottom portion 46 of the developer tank 42 are made of an insulator, such as PLEXIGLÁS, externally surrounded by a ground cover made of metal. A rear electrode 152 is disposed within the developer tank 42 and is spaced approximately 36 cm below the center of the interior surface of the cover plate board 12. A positive potential of approximately 35 kV is applied to the rear electrode 152 and the organic conductor of the photoreceptor 36 is grounded. The rear electrode 152 has a dimension of 51 cm by 41.3 cm and is positioned approximately photoreceptor 36 cm below the center of the board 12. The rear electrode 152 is biased to a positive potential d 35 kV with respect to the OC layer of the photoreceptor 36 The rear electrode 152 has an opening therein for accommodating the rotating nozzle unit 161 having two nozzles 162, spaced by a distance of approximately 17.8 cm. The uniformity of the deposition of the phosphor particles through the board 12 is controlled by adjusting the angular orientation of the rotating nozzles, as described in US Pat. No. 5,477,285, issued to Riddie et. al., December 19, 1995. As described above, the phosphor material, in the form of dry powder particles, of the desired color of light emission is dispersed from the phosphor feeder 54, for example by a borer , not shown, within a stream of air passing through the tube 56 into a Venturi tube 58, where it is mixed with the phosphor particles. The air-phosphorous mixture passes through channels into the tube 60, which imparts the triboelectric charge to the phosphorus powder due to the contact between the phosphor particles and the inner surface of the tube 60. For example, to positively charge the phosphor material. Phosphorus a polyethylene tube is used. The air-phosphorus mixture is directed into a rotating nozzle unit 161 and out of the nozzles 162. To prevent deposition of the phosphor material in the inner side wall of the rectangular board 12, two pairs of wall coverings 66 and 68 The lateral side of the board is used to form a rectangular roof arrangement, as described above. The time of phosphorus deposition using these parameters is approximately 45 seconds. A test was carried out using fifty development cycles on two cover plate boards 12 On a board, covers 66 and 68 did not have a ground plate lf disposed on the side view surface of the deck of the deck. covers. In the other board, covers 66 and 68 have a plate 70 grounded thereon. Decks 66 and 68 in both group tests were adjustable rather than stationary. The effectiveness of the plate 70 to ground was determined by defining two sample areas of 80 thousand x 80 thousand in each board and measuring the number of larger agglomerates of phosphorus particles in one area, and in the other area by measuring the amount of cross contamination. Cross contamination is defined as the number of phosphor particles in a given color, which are deposited in a line position designated for a different color. The sample area of agglomerates was located at the 8th diagonal corner of the board and the cross contamination sample area was located at the 6 o'clock edge of the board. The results of the test are summarized in the TABLE. TABLE It can be seen that the presence of the plate 70 to ground in the covers 66 and 68 provides a substantial reduction in defects of the board

Claims (5)

1. CLAIMS 1. An apparatus for developing, with suitable triboelectrically charged, light-emitting, light-emitting phosphor materials, a latent charge image formed in a photoreceptor that is disposed on an inner surface of a coating plate board having a peripheral side wall, the apparatus comprises: a developer tank having a side wall closed at one end by a lower portion and at the other end by a board support having an opening therethrough to provide access to the board; a rear electrode disposed within the developer tank separated from, but parallel to, the interior surface of the cover plate board, the rear electrode has a potential applied thereto to establish a displacement field between the rear electrode and the photoreceptor; At least one injector for injecting the triboelectrically charged, light-emitting, light-emitting phosphor materials into the developer tank between the back electrode and the cover plate board, the triboelectrically charged phosphor materials have a charge of same polarity as the potential applied to the back electrode, where phosphor materials are directed towards the photoreceptor in the cover plate board; and a side wall arrangement of the side of the board disposed around the side wall to repel the phosphor materials triboelectrically charged therefrom. The apparatus according to claim 1, wherein the sidewall cover arrangement of the side of the board comprises two pairs of insulating members. The apparatus according to claim 2, wherein the insulating members also comprise a ground plate on a surface of each of the insulating members. The apparatus according to claim 3, wherein the ground plate is disposed on a surface of the insulating members facing the peripheral side wall of the cover plate board. 5. A method for developing a latent charge image on a photoreceptor that is arranged on an interior surface of a cover plate board of a cathode ray tube (CRT) with phosphor materials, light emitters, dry powder, triboelectrically loaded, the cover plate board has a peripheral side wall, the method comprises the steps of: placing the cover plate board on a board support of a developer, the developer includes a sidewall cover arrangement of the side of the board arranged around the peripheral side wall of the cover plate board, a tank having a side tank wall closed at one end by a lower portion and at the other end with the board support with an opening therethrough to provide access to the cover plate board, a rear electrode disposed within the developer tank and separate from, but parallel to, the interior surface of the deck. cover plate; grounding the photoreceptor; providing a load on the sidewall cover arrangement of the side of the board to prevent triboelectrically charged phosphor materials from accumulating thereon; provide a positive potential to the rear electrode to establish a displacement field between the rear electrode and the photoreceptor; and injecting the light-emitting phosphor, dry powder, triboelectrically loaded material into the developer tank, between the back electrode and the cover plate board, the triboelectrically charged phosphor materials have a charge of the same polarity as the applied potential to the back electrode, where the phosphor material is directed towards the photoreceptor on the cover plate board. SUMMARY The invention includes a developer apparatus 40, 140 to develop a latent charge image formed in a photoreceptor 36 disposed on an inner surface of a cover plate board 12. The developer apparatus 40, 140 comprises a developer tank 42 having a side wall 44 closed at one end by a lower portion 46 and at the other end by a board support 48 having an opening 50 therethrough to provide access to board 12 of cover plate. The rear electrode 52 has a potential applied thereto to establish an electrostatic displacement field between the rear electrode and the photoreceptor 36, which is grounded. The triboelectrically charged, dry powder light emitting phosphor material has a charge of the same polarity as the potential applied to the back electrode 52, is injected into the developer tank 42, between the back electrode 52 and the plate board 12 covering. The triboelectrically charged phosphorous material is directed towards the photoreceptor 36 in the cover plate board 12 by the electrostatic displacement field. The sidewall covers 66, 68 of the side of the board are arranged around the peripheral side wall 18 of the cover plate board 12 for repelling the triboelectrically charged phosphor material from the side wall 18 of the board. The method for developing the latent charge image formed in the photoreceptor 36, which is disposed on the inner surface of the cover plate board 12, includes the steps of placing the cover plate board 12 on a board support 48 of the apparatus. 40, 140, and placing the side wall cover means 66, 68 on the side of the board near the side wall 18 of the cover plate board 12. The photoreceptor 36 is grounded and a potential is applied to the rear electrode 52. The triboelectrically charged phosphor materials, which have a charge of the same polarity as the potential applied to the back electrode 52, are introduced into the developer tank 42, between the back electrode 52 and the cover plate board 12. The phosphor material is directed towards the photoreceptor 36 in the cover plate board 12 by the electrostatic displacement field applied and repelled from the side wall 18 of the cover plate board by the side wall covers 66, 68 on the side of the cover plate. board.