CN1158489A - Method of electrophotographically manufacturing luminescent screen assembly for cathode-ray tube - Google Patents

Abstract

Disclosed is a method for manufacturing CRT (10) fluorescent screen components (22, 24) on the internal surface of a screen panel (12) with a photoabsorption substrate (23) by electrophotography, which comprises an organic conductive (OC) layer (32) which is covered by an organic photoconductive (OPC) layer (34) and arranged on the substrate. Electrostatic voltage is formed on the OPC layer; the light of an exposure platform selectively enables area discharging. Fluorescent material makes the discharging area to be developed to form a first color light fluorescent cell (G). A second color light fluorescent cell (B) can be formed by repeating the above steps. A gap g is formed between certain first fluorescent cell and certain second fluorescent cell. Then an electrostatic charge is created on the OPC layer and the fluorescent cells. Floodlight exposure is realized on the OPC layer through ultraviolet light, and a third fluorescent cell (R) is formed through developing the rest opening areas and gaps by a third fluorescent material.

Description

Make the method for luminescent screen assembly for cathode-ray tube with electrofax

The present invention relates to electrofax system screen process (EPS), utilize the fluorescence structure material of triboelectric charging to make the method for cathode ray tube (CRT) luminescent screen assembly, particularly use the method for the device fabrication luminescent screen assembly littler than conventional equipment.

United States Patent (USP) 4921767 (1990.5.1. authorizes people such as Datta) has disclosed a kind of triboelectric charging fluorescence structure material that utilizes, and makes the method for the luminescent screen assembly on the CRT screen inner surface with electrofax.In this patented method, cover organic light-guide electricity (OPC) layer on organic conductive (OC) layer by electrostatic charging to positive voltage.Then, by removably being attached to the shadow mask in the screen dish, make the OPC layer by light exposure from the suitable light source in the Trinity exposure desk.This light is to approach from a branch of convergent angle incident in the electron beam of electron gun.On the light discharge zone of OPC layer with first kind in the light-emitting fluophor of three kinds of triboelectric chargings of deposit (just).After each exposure, mobile light diverse location to the exposure desk is with the incidence angle exposure by other electron beam.Need expose altogether three times according to three different light positions in the Trinity exposure desk, make and subsequently the deposit fluorophor is formed fluoroscopic OPC layer region discharge.

After the exposure technology step, take off shadow mask from the screen dish, the screen dish is placed the matrix developer, this developer comprises suitably prepd light absorption black matrix material dry powder shape particle.In developer,, it is deposited on the OPC layer that fills positive charge by positive development to host material triboelectric charging (bearing).

The OPC layer that has matrix is recharged equably to positive potential, and shadow mask is embedded the screen dish again.The screen dish is placed on the first accurate exposure desk, use up the OPC layer segment discharge that makes corresponding to the unit and fluorescence unit position of sending out first coloured light.The first accurate exposure desk provides the light that has near the convergent angle of a branch of incidence angle in the electron beam.Before the deposit fluorophor, take off shadow mask, the screen dish is placed first developer that contains the fluorophor of sending out first coloured light from the screen dish.In developer,, it is deposited on the OPC layer region of discharge by negative development to sending out the fluorescent material triboelectric charging of first coloured light.Utilize second, third accurate exposure desk and developer, repeat charging, exposure and the developing process of secondary OPC layer again.The light of each has and is similar to second and the convergent angle of three electron-beam respectively in these two accurate exposure desks.United States Patent (USP) 5340674 (1994.8.23. authorizes people such as Moscony) utilizes the variation of above-mentioned technology, with EPS process deposit light absorption matrix.In the patent that authorize back one, at three kinds of colour light emitting phosphor depositions after the OPC layer, OPC layer with little space between the fluorescent material of sending out different colours light is charged to negative potential, and with the fluorophor exposure of floodlight to repeatedly putting, the current potential of the OPC layer segment that is covered by fluorophor is not discharged.By negative development, the black matrix material granule of triboelectric charging (bearing) is deposited on the discharge portion of OPC layer.With the problem of this process is on the less former fluorophor of sending out colourama that has deposited of black matrix deposition of materials.Needn't invest the very big benefit that routine is used for the Trinity exposure desk of matrix technology though the exposure of the floodlight of deposit matrix has brought, defective is that the colourama fluorophor of sending out of black matrix material has impurity.

But, by before the step of exposure that fluorophor utilized of sending out colourama in deposit be reduced by at least an accurate exposure desk and embedding and the relevant step of taking off shadow mask afterwards, can save equipment cost and processing time considerablely.In addition, minimizing embeds and takes off one of shadow mask step and can reduce shadow mask or fluoroscopic damage probability.

The purpose of this invention is to provide a kind of method, be included in deposit light absorption matrix on the CRT screen inner surface, repeatedly put volatilizable OC layer thereon, and on this OC layer, repeatedly put volatilizable OPC layer with EPS technology manufacturing color CRT luminescent screen assembly.On the OPC layer, set up substantially uniform voltage.Then, make a large amount of OPC layer first select the zone by shadow mask with holes, to change the voltage that OPC layer first is selected on the zone to visible light exposure from first exposure desk.Then, make first to select the zone to develop, forms the unit and fluorescence unit of a large amount of first coloured light with the fluorescent material of sending out colourama of first triboelectric charging.On OPC layer and a large amount of unit and fluorescence unit of sending out first coloured light, rebulid substantially electrostatic pressure uniformly.Make a large amount of OPC layer second select the zone by shadow mask with holes, to change the voltage that OPC layer second is selected on the zone to visible light exposure from second exposure desk.The fluorescent material of sending out colourama with second triboelectric charging makes OPC layer second select the zone to develop, and forms a large amount of unit and fluorescence units of sending out second coloured light.The unit and fluorescence unit of sending out first and second coloured light is overlapped on the part of matrix at least, thereby produces the gap at least between the unit and fluorescence unit of a certain first and second coloured light.On OPC layer and a large amount of unit and fluorescence unit of sending out first, second coloured light, rebulid substantially electrostatic pressure uniformly.With the UV radiation to OPC layer floodlight exposure, make on the remaining open area and the gap on voltage change.At last, developed in the remaining open area of OPC layer, form a large amount of unit and fluorescence units of sending out the 3rd coloured light with the fluorescent material of sending out the 3rd coloured light.The fluorescent material of sending out the 3rd coloured light also is deposited in the gap, but the material of sending out the 3rd coloured light in this gap is shielded by light absorption matrix.

In the accompanying drawing,

Fig. 1 is the plane graph of the band localized axial section of the color CRT made by the present invention;

Fig. 2 is the section of the luminescent screen assembly of picture tube shown in Figure 1;

Fig. 3-10 illustrates the screen dish section in several conventional steps of EPS technology; With

Figure 11 and 12 illustrates the screen dish section by process of the present invention.

Fig. 1 illustrates the color CRT 10 of band glass bulb 11, and it comprises rectangle screen dish 12 and the tubular neck portions 14 that links to each other by rectangular cone 15.Cone 15 has with anode button 16 and contacts and extend to internal conductive coating (not shown) in the neck 14.Screen dish 12 comprises watches panel or substrate 18 and with periphery flange or the sidewall 20 of melted glass 21 sealing-ins on cone 15.Tricolour phosphor screen 22 is located on substrate 18 inner surfaces.Phosphor screen 22 shown in Figure 2 is the line-screen that comprises a large amount of screen units.Screen unit is made up of phosphor strip R, the G and the B that launch red, green, blue respectively, be arranged in three or ternary color-set or pixel by circular order.Phosphor strip is along extending perpendicular to the plane that produces electron beam usually.Normal viewing location at embodiment sees that phosphor strip vertically extends.Phosphor strip preferably is positioned at the opening that is limited by light absorption matrix 23, is overlapped on the light absorption matrix to the small part phosphor strip, just as is known in the art situation.Also can form the point-like screen with this technology.The electrically conductive layer 24 that is preferably aluminium covers on the screen 22, provides one to apply even current potential and by the device of panel 18 reflections from the light of unit and fluorescence unit emission to screen 22.Screen 22 and the aluminium lamination 24 that covers are formed luminescent screen assembly.The porous color selection utmost point or shadow mask 25 are used conventional method, detachably install with the predetermined space of relative fluorescence screen assembly.

Electron gun 26 by dotted line signal among Fig. 1 is contained in the neck 14 coaxially, and the aperture that produces and pass on the shadow mask 25 along converging passageway guiding three-beam electron-beam 28 arrives phosphor screen 22.Electron gun is conventional, can be any suitable known electronic rifle of the prior art.

Picture tube 10 is designed to be used in the external magnetic deflection yoke that is fixed on cone and the neck join domain, such as deflecting coil 30.When adding excitation, deflecting coil 30 scans the rectangular raster of three-beam electron-beam 28 on the action of a magnetic field lower edge phosphor screen 22 horizontally and vertically.Line P-P among Fig. 1 illustrates the initial deflection plane (zero deflection place) about deflecting coil 30 middle parts.For simplifying, the actual curve of deflection beam track is not shown in the deflection area.

With the EPS prepared phosphor screen described in the above-mentioned United States Patent (USP) 4921767.Fig. 3-10 illustrates part technology.At first, by prior art, for deposit light absorption matrix 23 prepare panel 12, promptly with alkali lye clean, rinsing in the water, with the buffered hydrofluoric acid corrosion with use water rinse again.Conventional wet type matrix method described in the most handy United States Patent (USP) 3558310 (1971.1.26. authorizes Mayaud) is provided with light absorption matrix 23 watching on plate 18 inner surfaces.In the wet type matrix method, for example use spin coating, suitable moisture photoresist liquid is coated on the inner surface of screen dish 12, dry then this solution forms photoresist layer.Then, shadow mask is inserted the screen dish, and should place (not shown) on the Trinitarian exposure desk by the screen dish, make photoresist layer actinic radiation exposure from light source by the opening incident on the shadow mask.With the imitation that is provided with from the light source repeated exposure in the three-beam electron-beam path of CRT electron gun more than twice.This light changes the solubility of subsequently photoresist layer of deposit fluorescent material being exposed the zone selectively.After three exposures, remove the screen dish from exposure desk, and remove shadow mask from the screen dish.Water develops photoresist layer, removes the zone of its more dissolving, thereby exposes the panel inner surface substrate, stays the harmless exposure area of photoresist layer of less dissolving.Suitable light absorbing material solution (not shown) is set on panel 18 inner surfaces, is uniformly dispersed on the photoresist layer zone of remaining less dissolving on the exposed portions serve of panel and the screen dish 12.Dry light absorbing material layer develops it with suitable solution, and the remainder of this solution dissolving and removal photoresist layer is repeatedly put light absorbing material, thereby forms the fenestra in the hypothallus that sticks to screen inner surface.

With volatilizable organic conductive material evenly coating have matrix 23 watch panel 18 inner surfaces, form organic conductive (OC) layer 32, for volatilizable organic light-guide electricity (OPC) layer of repeatedly putting 34 provides an electrode.OC layer 32 and the temperature of OPC layer 34 about 425 ℃ are volatile.Fig. 3 is illustrated in the screen dish 12 of the OC layer 32 of watching carrying substrates on the panel 18 23 and band OPC layer 34.The material that is suitable for OC layer 32 comprises some quaternary ammonium polyeletrolyte of mentioning in the United States Patent (USP) 5370952 (1994.12.6 authorizes people such as Datta).Constitute OPC layer 34 by the suitable resin that forms the solution that covers on the OC layer 32, electronic donor material, electronics acceptor material, surfactant and organic solvent.United States Patent (USP) 5413885 (1995.5.9. authorizes people such as Datta) has disclosed the example that is suitable for forming OPC layer 34 material.On the other hand, matrix 23 can be formed by above-mentioned United States Patent (USP) 4921767 or the described EPS technology of United States Patent (USP) 5229234 (1993.7.20. authorizes people such as Riddle).

As shown in Figure 4, make OPC layer 34 be charged as the positive potential of 200-800V scope with glow discharge apparatus 36.Then, as shown in Figure 5, shadow mask 25 is inserted screen dish 12, screen dish 12 is placed on the first accurate exposure desk 38, be used for making the OPC layer exposure that is filled with positive charge by shadow mask 25 from placing the xenon flash lamp 40 in the exposure desk or the light of the light source that for example other intensity of mercury-arc lamp and so on is enough.With pass aperture on the shadow mask 25, along with irradiate light OPC layer 34 from the identical angle of one of electron beam of CRT electron gun 26, make by the discharge of the zone of photograph, form the charging figure.Shadow mask is taken off from screen dish 12, as shown in Figure 6, the screen dish is placed the first fluorescer developer 42, developer 42 comprises the fluorescent material of sending out first kind of coloured light, the fluorescent material of dry powder powder green light for example, handle with suitable charge control material in advance on its surface, seals these particles and can form the friction positive charge thereon.In developer to sending out the positive triboelectric charging of fluorescent powder grain of first kind of coloured light, and guiding OPC layer 34.Be called the known processes that " negative (reversal) " develops with this area, the positively charged fluorescent powder grain of sending out first kind of color of light is subjected to being formed at the positive charge zone of the charging figure on the OPC layer 34 to be repelled, and is deposited on its zone of being discharged.In the negative development, the triboelectric charging particle of screen structure material is subjected to the repulsion in the identical charging zone of OPC layer 34, is deposited on its zone of having discharged, forms a large amount of unit and fluorescence units of sending out first coloured light as bar shaped or point-like.The size of the unit and fluorescence unit of each first coloured light is a bit larger tham the opening size in the light absorption matrix 23, covers each opening fully and the parameatal light absorption host material that overlaps slightly.Then, as shown in Figure 7, the OPC layer 34 that is deposited with the unit and fluorescence unit of sending out first coloured light is recharged, rebulid the positive voltage in the 200-800V scope on OPC layer 34 and on the unit and fluorescence unit of sending out first coloured light of deposit with charging device 36.After recharging step, shadow mask 25 is embedded screen dish 12 again, screen dish 12 is placed again on the second accurate exposure desk 44, as shown in Figure 8, this exposure desk has light source 40, and is identical with the light source of first exposure desk 38.With pass aperture on the shadow mask 25, along with irradiate light OPC layer 34 from the angle of the second beam electrons Shu Xiangtong of CRT electron gun 26, the irradiated area discharge forms the second charging figure.Shadow mask is taken off from screen dish 12, as shown in Figure 9, the screen dish is placed the second fluorescer developer 46, this developer 46 comprises the fluorescent material of sending out second coloured light, the fluorescent material of dry powder powder blue light-emitting for example, handle with suitable charge control material in advance on the surface of fluorescent material, seals these particles and can form the friction positive charge thereon.In developer to sending out the positive triboelectric charging of fluorescent powder grain of second coloured light, and guiding OPC layer 34.By " bearing " developing process method, the positive charge that just charges the zone and be positioned at the first coloured light unit and fluorescence unit that the fluorescent powder grain of sending out second coloured light that is just being charged is subjected to being formed on the charging figure of OPC layer 34 repels, and be deposited on the zone of having discharged, form a large amount of unit and fluorescence units of sending out second coloured light.The size of unit and fluorescence unit that is deposited on each second coloured light on the OPC layer 34 covers each opening and the parameatal light absorption host material that overlaps slightly fully also greater than the matrix opening size.

As shown in figure 10, the OPC layer 34 that is deposited with first and second unit and fluorescence units with 36 pairs of charging devices recharges, and constitutes positive voltage again on first, second unit and fluorescence unit of OPC layer 34 and deposit.The novelty of this process is shown in Figure 11 and 12.In order to simplify the remaining step of EPS process, reduce equipment cost and reduce the process time, with suitable light source 48, comprise in advance that as mercury-arc lamp floodlight irradiation deposit sends out the OPC layer 34 that is recharged of the unit and fluorescence unit of first, second coloured light, this light source 48 has the spectral distribution of the ultraviolet light that comprises wavelength 365nm.The filter 50 of logical, the visible photoresistance of a ultraviolet light can be set between light source 48 and OPC layer 34, Corning Glass Works for example, Corning, No. 5840 filters that NY makes are with the light of filtering wavelength greater than 400nm.Ultraviolet light is incident on OPC layer 34 remaining open area, is promptly sent out the zone of the unit and fluorescence unit covering of first and second coloured light, makes it be discharged to the value that reduces from initial value., the unit and fluorescence unit of first, second coloured light on other zone of OPC layer 34 that overlaps will absorb the ultraviolet light of incident, and shielding action is provided thus, and the positive charge on the substrate OPC layer 34 will not reduce like this, and remain on its initial value.Then, as shown in figure 12, the screen dish 12 that will comprise the OPC layer 34 that is shone by floodlight is sent in the 3rd developer 52, this developer 46 comprises the fluorophor of sending out the 3rd coloured light, the fluorescent material that glows of dry powder powder for example, phosphor surface is handled with suitable charge control material in advance, seals these particles and can form the friction positive charge thereon.In developer to sending out the positive triboelectric charging of fluorescent material of the 3rd coloured light, and guiding OPC layer 34.The fluorescent material of sending out the 3rd coloured light that is just being charged is subjected to being positioned at the positive charge zone repulsion of first, second deposit unit and fluorescence unit, and by " bearing " development, be deposited on the residue open area of being shone by floodlight, discharged, on this zone, form a large amount of unit and fluorescence units of sending out the 3rd coloured light.The size of unit and fluorescence unit that is deposited on each the 3rd coloured light on the OPC layer 34 is also greater than the matrix opening size, guaranteeing that not having the gap produces, and the parameatal light absorption host material that overlaps slightly.Owing to before the 3rd fluorescer develops, shine with floodlight, make the open area discharge of remaining OPC layer 34, thereby do not need the 3rd accurate exposure desk, need and not embed and remove shadow mask before the exposure of the 3rd OPC layer afterwards yet, thereby saved the processing time, reduced damage shadow mask or fluoroscopic possibility.

Shown in Figure 11 and 12, certain part has little gap " g " at least between the adjacent unit and fluorescence unit of sending out first and second coloured light.This gap is positioned on the light absorption matrix 23.Above-mentioned floodlight step of exposure not only makes the 34 remaining open area discharge of OPC layer, also make the OPC layer discharge in the gap " g ", this gap " g " is being deposited between first and second coloured light unit and fluorescence unit in advance, thereby the fluorescent material of sending out the 3rd coloured light is deposited on this gap and the remaining open area of OPC layer.Yet, can't the exert an influence problem of phosphor screen quality of the fluorescent material of sending out the 3rd coloured light is arranged in the gap, because 23 shieldings of light absorption matrix overlap at fluorescent material on the matrix and the fluorescent material in the gap, make it does not passed the radiation of visible light of viewing screen 18.

Use appropriate fixative, as methylisobutylketone (MIBK) contact fluorescer, the fluorophor of sending out the light of three kinds of colors is fixed on the above-mentioned OPC layer 34, fixative slowly dissolves the polystyrene of OPC layer 34 and unit and fluorescence unit is adhered on it.Then to unit and fluorescence unit coated with film, on screen 22, form the smooth surface layer, the evaporation of deposit thereon aluminium lamination 24.Film forming can be conventional spraying or latex film, or the dry type film, for example described in the United States Patent (USP) 5028501 (1991.7.2. authorizes people such as Ritt).Behind film and deposit aluminium, curing this luminescent screen assembly about 30 minutes under about 425 ℃ temperature, remove the volatile component of screen assembly.

Claims (2)

1, a kind of method of making the luminescent screen assembly (22,24) on CRT (10) screen dish (12) inner surface with electrofax, matrix (23) is arranged on the described inner surface of described screen dish, cover organic conductive (OC) layer (32) of described matrix, organic light-guide electricity (OPC) layer (34) and a large amount of screen unit of the described organic conductive layers of covering, described screen unit comprises the unit and fluorescence unit (G, B, R) of sending out first coloured light, sending out second coloured light and Fa Di three coloured light, be arranged in the described matrix opening by color-set, it is characterized in that this method comprises the following steps:

A) go up foundation electrostatic pressure in fact uniformly at described OPC layer (34);

B) shadow mask (25) by perforate makes a large amount of first of described OPC layer select the zone to the visible light exposure from first exposure desk (38), to change the voltage on it;

C) make described first of described OPC layer select the zone to develop with fluorescent material first triboelectric charging, that the dry powder powder is sent out colourama, forms the unit and fluorescence unit (G) of a large amount of first coloured light;

D) on the unit and fluorescence unit of described OPC layer and described first coloured light, set up electrostatic pressure in fact uniformly again;

E) by described shadow mask make be different from described first select the zone, described OPC layer a large amount of second select the zone to visible light exposure, to change the voltage on it from second exposure desk (44);

F) make described second of described OPC layer select the zone to develop with fluorescent material second triboelectric charging, that the dry powder powder is sent out colourama, form a large amount of unit and fluorescence units (B) of sending out second coloured light, the unit and fluorescence unit of described first and second coloured light overlaps on the described matrix of part at least, thereby in that some is sent out between the unit and fluorescence unit of first and second coloured light and produces gap (8) at least;

G) on the unit and fluorescence unit of described OPC layer and described first, second coloured light, set up electrostatic pressure in fact uniformly again;

H) shine described OPC layer with the ultraviolet radiation floodlight, make the remaining open area voltage discharge that comprises the gap; With

I) with the fluorescent material of sending out colourama the 3rd triboelectric charging, the dry powder powder developed in the remaining open area of described OPC layer, form a large amount of unit and fluorescence units (R) of sending out the 3rd coloured light, the fluorescent material of described the 3rd coloured light also is deposited in the gap.

2, the method for claim 1 is characterized in that step I) also comprise the following steps: afterwards

J) unit and fluorescence unit (G, B, R) with described first, second and the 3rd coloured light is fixed on the described OPC layer (34), forms phosphor screen (22);

K) to described phosphor screen coated with film;

L) conductive layer that overlaps on described phosphor screen forms luminescent screen assembly (22,24); With

M) cure described luminescent screen assembly, remove volatile component.

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