JP2000243325A - Image forming device and pressure inspection method inside of image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To develop an inspection process using an easier method without inspecting an image forming device by actually displaying an image. SOLUTION: In an image forming device having an electron source having plural electron emitting elements 13 on a base board in an envelope 5, an image forming member (a face plate 4) oppositely arranged on the base board and a getter material 2 for maintaining a degree of vacuum in the envelope 5, a pressure detecting means 17 is arranged to detect pressure in the image forming device on the basis of a change in a surface color of the getter material 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus provided with an electron source and an image forming member (phosphor) for forming an image by irradiating an electron beam emitted from the electron source in a vacuum vessel. The present invention relates to an image forming apparatus provided with a unit for inspecting the pressure in a vacuum vessel and a method for inspecting the pressure.

[0002]

2. Description of the Related Art CRTs have been widely used as image forming apparatuses for displaying images using electron beams.

On the other hand, in recent years, flat-panel display devices using liquid crystal have become widespread in place of CRTs. However, since the flat panel display device is not a self-luminous type, there is a problem that a backlight must be provided, and development of a self-luminous type display device has been desired.

A plasma display has recently begun to be commercialized as a self-luminous display device.
The principle of light emission is different from RT.
At present, it must be said that it is slightly inferior to CRT due to its good color development. Further, if a plurality of electron-emitting devices are arranged and used in a flat panel image forming apparatus, it is expected that light emission of the same quality as that of a CRT can be obtained, and much research and development has been carried out.

[0005] The electron-emitting device constituting the electron source of the flat plate type image forming apparatus is required to be able to form uniformly over a large area and to be simple in the manufacturing process.

As a typical example of an electron-emitting device that may satisfy this condition, a surface conduction electron-emitting device having a structure schematically shown in FIG. 13 and an image forming apparatus using the same have been proposed.

FIGS. 13A and 13B show a surface conduction electron-emitting device and an image forming apparatus using the same, wherein FIG. 13A is a plan view and FIG. 13B is a sectional view. In FIG. 13, 1
31 denotes a substrate, 132 and 133 denote device electrodes, 134 denotes a conductive thin film, and 135 denotes an electron-emitting portion.

The details of the structure and manufacturing method of the electron-emitting device and the image forming apparatus are described in, for example,
It is described in JP-A-235255, JP-A-7-235275, and the like. Hereinafter, a brief description will be given of a method of manufacturing an image forming apparatus in which a plurality of such surface conduction electron-emitting devices are arranged on a substrate.

Regarding the arrangement of the elements on the substrate, for example,
A large number of electron-emitting devices are arranged in parallel, a large number of rows of electron-emitting devices having both ends of each element connected by wiring (called a row direction), and arranged in a direction orthogonal to the wiring (column direction). ), An array configuration (called a ladder type) in which electrons are controlled and driven by a control electrode (called a grid) installed in a space above the electron source, and n
An arrangement form (referred to as a simple matrix arrangement) in which the Y-directional wirings are disposed via an interlayer insulating layer, and the X-directional wiring and the Y-directional wiring are connected to a pair of device electrodes of the surface conduction electron-emitting device, respectively. No.

Next, the simple matrix arrangement will be described in detail.

According to the three basic features of the surface conduction electron-emitting device described in the above-mentioned publication, the electrons emitted from the surface conduction electron-emitting device have a threshold voltage higher than the threshold voltage. Can be controlled by the peak value and width of the pulse-like voltage applied to the. On the other hand, below the threshold voltage, almost no electrons are emitted. According to this characteristic, even when a large number of electron-emitting devices are arranged, if the pulse-like voltage is appropriately applied to each of the devices, the surface-conduction electron-emitting device is selected according to an input signal, and the electron is selected. The amount of release can be controlled.

Hereinafter, the configuration of the electron source substrate configured based on this principle will be described with reference to FIG.

As shown in FIG. 11, m X-direction wirings 5
2 is composed of D _x1 , D _x2 ,..., D _xm , and is formed on the insulating substrate 51 by a vacuum evaporation method, a printing method, a sputtering method, or the like, and is made of a conductive metal or the like having a desired pattern. The material, the film thickness, the wiring width, and the like are designed so that a substantially uniform voltage is supplied to many surface conduction electron-emitting devices. An interlayer insulating layer (not shown) is provided between the m X-directional wirings 52 and the n Y-directional wirings 53, and is electrically separated to form a matrix wiring. Both are positive integers).

The interlayer insulating layer (not shown) is made of SiO ₂ or the like formed by a vacuum deposition method, a printing method, a sputtering method, or the like, and has a desired shape on the entire surface or a part of the substrate 51 on which the X-direction wiring 52 is formed. The thickness, material, and manufacturing method are appropriately set so as to be formed, and particularly to withstand the potential difference at the intersection of the X-direction wiring 52 and the Y-direction wiring 53. The X-direction wiring 52 and the Y-direction wiring 53 are led out as external terminals.

Further, opposing electrodes (not shown) of the surface conduction electron-emitting device 54 are provided with m X-direction wirings 52 (D _x1 , D _x
x2, ···, D _xm) and n Y-directional wirings 53 (D _y1, D
_y2 ,..., _Dyn ) are electrically connected to each other by a connection made of a conductive metal or the like.

Here, m X-directional wires 52 and n Y wires
Some or all of the constituent elements of the conductive metal of the element electrode facing the directional wiring 53 and the connection 56 may be the same or different.

As will be described in detail later, the X-direction wiring 52 is provided with a scanning signal (not shown) for scanning a row of the surface conduction electron-emitting devices 54 arranged in the X direction in accordance with an input signal. It is electrically connected to the scanning signal applying means. On the other hand, the Y-direction wiring 53 is a modulation signal generating means (not shown) for applying a modulation signal for modulating each column of the surface conduction electron-emitting devices 54 arranged in the Y direction according to an input signal.
Is electrically connected to

Further, the drive voltage applied to each element of the surface conduction electron-emitting device is supplied as a difference voltage between a scanning signal and a modulation signal applied to the element.

Next, an electron source using the electron source substrate manufactured as described above, and an image forming apparatus used for display and the like will be described with reference to FIGS. FIG. 7 is a schematic diagram of a fluorescent film, and FIG. 12 is a basic configuration diagram of an image forming apparatus.

In FIG. 12, reference numeral 14 denotes an electron-emitting device 13.
, A rear plate 15 to which the electron source substrate 14 is fixed, 4 a fluorescent film 7 on the inner surface of the glass substrate 6
And a face plate on which a metal back 8 and the like are formed. Reference numeral 3 denotes a support frame, which is coated with frit glass on the rear plate 15, the support frame 3, and the face plate 4 and is heated at 400 to 500 ° C. in the air or in nitrogen.
By baking for 0 minutes or more, sealing is performed to form the envelope 5.

In FIG. 12, reference numerals 11 'and 12' denote an X-direction wiring and a Y-direction wiring connected to a pair of device electrodes of the surface conduction electron-emitting device. Also, the wiring to these device electrodes, if the device electrode and the wiring material are the same,
It may be called an element electrode.

The envelope 5 is composed of the face plate 4, the support frame 3, and the rear plate 15 as described above. However, since the rear plate 15 is provided mainly for the purpose of reinforcing the strength of the substrate 14, the If the substrate 14 itself has sufficient strength, the separate rear plate 15 is unnecessary, and the substrate 14
Alternatively, the support frame 3 may be directly sealed, and the envelope 5 may be constituted by the face plate 4, the support frame 3, and the substrate 14.

On the other hand, by providing a support (not shown) called a spacer between the face plate 4 and the rear plate 15, the envelope 5 having sufficient strength against the atmospheric pressure can be formed. .

At the time of performing the above-mentioned sealing, in the case of a color image forming apparatus, it is necessary to make the respective phosphors and the electron-emitting devices shown in FIG. 7 correspond to each other. There is.

The envelope 5 passes through an exhaust pipe (not shown).
After the degree of vacuum is set to about 3 × 10 ⁻⁵ Pa, sealing is performed.

In some cases, a getter process is performed to maintain the degree of vacuum after the envelope 5 is sealed. This is because the getter material disposed at a predetermined position (not shown) in the envelope 5 is heated by a heating method such as resistance heating or high-frequency heating immediately before or after the envelope 5 is sealed. This is a process for forming a deposited film. The getter material is usually composed mainly of Ba or the like.
The vacuum degree of 3 × 10 ⁻³ or 1 × 10 ⁻⁷ Pa is maintained.

In the image display device completed as described above, each electron-emitting device has terminals D _{x1 to} D _xm , D _y1 outside the container.
To _Dyn to emit electrons by applying a voltage, apply a high voltage of several kV or more to the metal back 8 or a transparent electrode (not shown) through the high voltage terminal Hv to accelerate the electron beam, and The image is displayed by causing excitation and light emission by colliding with the light.

[0028]

In an image forming apparatus using the above-described surface conduction electron-emitting device, it is necessary that the inside of the envelope is maintained at a high vacuum for a long period of time. For this purpose, it is desirable that the pressure in the container can be detected before the image forming apparatus is completed as a final product. Because of the shutoff, there was no direct way to check the pressure in the container.

If the pressure inside the image forming apparatus is abnormal (vacuum leak or the like), unnecessary components are mixed into the image forming apparatus. The mixed gas is ionized by the electrons emitted from the electron source, accelerated by an electric field formed between the electron source and the image display member,
In some cases, the electron source may be damaged, or a discharge may be caused to destroy the electron source. In such a case, the image forming apparatus becomes defective and cannot be used as a product.

Conventionally, a process of actually performing image display and inspection has been performed, but development of an inspection process using a simpler method has been desired.

[0031]

In order to achieve the above object, an image forming apparatus according to the present invention comprises: an electron source having a plurality of electron-emitting devices disposed on a substrate in an envelope; In an image forming apparatus having an image forming member arranged to face a substrate and a getter material for maintaining a degree of vacuum in the envelope, the image forming device performs the image forming based on a change in the surface color of the getter material. A pressure detecting means for detecting a pressure in the device is provided.

Further, the image forming apparatus according to the present invention is characterized in that, in an envelope, an electron source having a plurality of electron-emitting devices disposed on a substrate, and an image forming member disposed to face the substrate. ,
In an image forming apparatus having a getter material for maintaining a degree of vacuum in the envelope, a pressure inside the image forming apparatus is increased based on a change in a surface color of a non-evaporable getter material formed by a thermal spraying method. It is characterized in that pressure detecting means for detecting is provided.

Further, according to the pressure test method for an inside of an image forming apparatus according to the present invention, an electron source in which a plurality of electron-emitting devices are arranged on a substrate in an envelope is disposed so as to face the substrate. The image forming member, and a method for inspecting the pressure inside the image forming apparatus having a getter material for maintaining the degree of vacuum in the envelope, based on a change in the surface color of the getter material, It is characterized in that the pressure in the image forming apparatus is detected.

Further, according to the pressure inspection method for an inside of an image forming apparatus according to the present invention, in an envelope, an electron source having a plurality of electron-emitting devices disposed on a substrate is disposed so as to face the substrate. And a method for inspecting the pressure inside the image forming apparatus having a getter material for maintaining the degree of vacuum in the envelope, wherein the non-evaporable getter material formed by the thermal spraying method is used. The pressure in the image forming apparatus is detected based on a change in surface color.

Here, a CCD camera, a video camera, or the like can be used as an observation means for observing a change in the surface color of the non-evaporable getter material.

The thickness of the non-evaporable getter material formed by the above-mentioned thermal spraying method is preferably 10 to 100 μm.

Further, the electron source may be an electron source in which a plurality of electron-emitting devices arranged in a matrix are arranged on a substrate.

The electron source may have a surface conduction electron-emitting device.

[0039]

Embodiments of the present invention will be described below.

FIG. 2 schematically shows an example of the configuration of the image forming apparatus according to the present invention. In FIG. 2, reference numeral 1 denotes an electron source in which a plurality of electron-emitting devices 13 are arranged on a substrate, and appropriate wirings 11 and 12 are provided. Reference numeral 3 denotes a support frame, and reference numeral 4 denotes a face plate. At a joint portion, they are adhered to each other using frit glass or the like to form an envelope 5.

The face plate 4 is formed by forming a fluorescent film 7 and a metal back 8 on a glass substrate 6, and this portion becomes an image display area. The phosphor film 7 is made of only a phosphor in the case of a display device for displaying a black and white image. However, when displaying a color image, the phosphor film 7 is composed of phosphors of three primary colors of red, green and blue. Call) is formed,
In some cases, the structure is separated by a black conductive material.
Black conductive material, depending on its shape, black stripe,
It is called a black matrix. Details will be described later.

The metal back 8 is formed of a conductive thin film of Al or the like. The metal back 8 converts the light, which has been emitted from the phosphor, that travels toward the electron source 1 into the glass substrate 6.
To improve the brightness by reflecting in the direction of
It also functions to prevent the gas remaining in the phosphor from damaging the phosphor due to the impact of ions generated by ionization by the electron beam. Further, it provides conductivity to the image display area of the face plate 4 to prevent charge from being accumulated, and serves as an anode electrode for the electron source 1. The metal back 8 is electrically connected to the high-voltage terminal Hv so that a voltage can be applied from outside the envelope 5 through the high-voltage terminal Hv.

On the wiring 12 (upper wiring), a non-evaporable getter 2 is formed as an inspection object for maintaining the pressure in the envelope 5 and for inspecting the pressure in the envelope 5. . The non-evaporable getter 2 is formed by a low pressure plasma spraying method.
The thickness of the prepared getter film is to maintain the exhaust capability for a long period of time, and to maintain the getter capability of the raw material powder for easy handling. The thickness is also determined, and is preferably about 10 μm or more. Further, in order to prevent film peeling after thermal spraying, the thickness of the getter material is preferably 100 μm or less. As the getter material, a commonly used non-evaporable getter can be used. For example, Ti, Zr, H
Metals such as f, V, Nb, Ta, W, and alloys thereof can be used. In addition, A1, F
e, Ni, Mn, etc. may be contained.

Since the surface of the sprayed film of the getter has irregularities of several μm to several tens μm, it has a larger surface area than the surface of the vapor-deposited film that is vacuum-deposited on a smooth surface, and therefore can have a higher pumping speed. .

In addition, a film having a thickness of about 10 to 100 μm can be easily formed in a short time by a single thermal spraying. By forming such a thick film, the life of the getter material can be extended. it can.

A non-evaporable getter as an inspection object is connected to the wiring 1
It is also possible to provide it in an area different from the area above 2 (upper wiring) and use it for inspection. With such an arrangement, an inspection window or the like is provided at a portion away from the image display area, and when the image forming apparatus is completed, the observation window can be hidden by a frame material or the like.

In FIG. 2, reference numeral 11 denotes a row selection terminal for selecting a row of elements to emit electrons, and reference numeral 12 denotes a signal input for inputting a signal for controlling the amount of electron emission of the electron-emitting devices belonging to the selected row. Terminal. Note that the row selection terminal 11 is connected to the X-direction wiring in the electron source, and the signal input terminal 12 is connected to the Y-direction wiring. The form of these terminals is appropriately selected depending on the structure of the electron source 1 and the control method, and is not limited to the structure shown in FIG.

In some cases, an evaporable getter 10 (a ring-shaped getter is schematically shown in FIG. 1) is provided in the envelope 5 as an auxiliary pump for keeping the interior of the envelope 5 at a vacuum.
In this case, the getter material is scattered in the image display area, and in order to prevent an electrical short circuit between the electrodes, the getter material is connected between the evaporable getter 10 and the area including the electron-emitting devices 13, the wiring groups 11, 12, and the anode electrode. , A shield 9 is provided. It should be noted that only the non-evaporable getter 2 formed on the wiring 12 is
If the inside can be kept sufficiently vacuum, the evaporable getter 10 and the shield 9 need not be formed.

Next, the structure of the above-described fluorescent film 72 will be described.

FIG. 7A shows a case where the phosphors 72 are arranged in stripes, and the phosphors 72 of three primary colors of red (72R), green (72G) and blue (72B) are formed in order. Are separated by a black conductive material 71. In this case, the portion of the black conductive material 71 is called a black stripe.

FIGS. 7B to 7D show the arrangement of the dots of the phosphor 72 in a grid pattern, which are separated by the black conductive material 71. In this case, the black conductive material 71 is called a black matrix.

As a patterning method of the black conductive material 71 and the phosphor 72 on the glass substrate 6, a slurry method, a printing method, or the like can be used. After the fluorescent film 7 is formed,
A metal back 8 is formed.

The support frame 3 formed as described above,
The face plate 4 and the electron source 1 are joined. If the substrate of the electron source 1 alone cannot withstand the atmospheric pressure after evacuation, a spacer is disposed between the electron source 1 and the face plate 4 or a reinforcing plate is provided on the back surface of the electron source 1. May be combined. The joining is performed by attaching frit glass to the joining portion and heating to about 400 ° C. As an actual operation, a heat treatment at about 300 ° C. is performed in the air to remove components contained as a binder in the frit glass (this step is referred to as “temporary firing”), and then an inert gas such as Ar ( In an inert gas, a heat treatment at 400 ° C. is performed to weld the joint.

When the electron source 1 includes a surface conduction electron-emitting device, necessary processing such as forming and activation of the electron-emitting device is performed, and the inside of the envelope 5 is sufficiently evacuated.

Thereafter, the entire envelope 5 is heated at a high temperature of about 350 ° C. for several hours to several tens of hours to activate the non-evaporable getter 2 on the wiring 12 and to connect an exhaust pipe (not shown) to a burner. Heat and seal off.

Finally, if necessary, the evaporative getter 10 (in the figure, a ring-shaped getter is schematically shown) provided in the envelope 5 is heated, and the getter material is attached to the inner wall of the envelope 5. Is deposited to form a getter material film. The getter film thus formed is located outside the image display area in the envelope 5.

In order to check whether or not the pressure in the completed image forming apparatus is normal, the non-evaporable getter 2 is passed through an observation window 16 provided in advance at the end of the image forming apparatus.
The inspection is performed using the detection means 17 for detecting the change in the surface color of the image. As a means for detecting the color of the surface of the non-evaporable getter 2, a small CCD camera, a video camera, or the like can be used.

The non-evaporable getter is sensitive to the oxygen partial pressure at a predetermined temperature in the image forming apparatus. That is, when the pressure in the image forming apparatus during the heating reaches the oxygen partial pressure equal to or higher than a predetermined value, the surface color of the non-evaporable getter changes to dark black, and the state of the pressure change is remarkably detected. It is possible to do.

In the present invention, the above-mentioned detecting means is used as a means for detecting the surface color change. As a method of determining the difference in color change, the surface color at a predetermined temperature under various oxygen partial pressure conditions is stored in a storage area in the inspection apparatus in advance and compared with the stored surface color. There is a method of detecting that the value does not exceed the threshold value. Further, it is also possible to make a determination by detecting the light reflectance or the like.

If the pressure is abnormal in the final stage of the image forming apparatus, the surface color of the non-evaporable getter 2 must have changed. Inspection becomes possible.

Next, NTS is performed by the above-described image forming apparatus.
An example of a structure of a driving circuit for performing television display based on a C-system television signal will be described with reference to FIG. 14, reference numeral 141 denotes an image forming apparatus (also referred to as a display panel) of the present invention, 142 denotes a scanning circuit, 143 denotes a control circuit, and 144 denotes a shift register. Also, 14
5 is a line memory, 146 is a synchronization signal separation circuit, 147
Is a modulation signal generator, and Vx and Va are DC voltage sources.

The image forming apparatus 141 has terminals _{Dox1 to Dox1
oxm} , terminals _{Doy1 to Doyn} , and a high voltage terminal Hv are connected to an external electric circuit. Terminals D _{ox1 -D
oxm} is a scanning device for sequentially driving electron sources provided in the image forming apparatus, that is, a group of surface conduction electron-emitting devices arranged in a matrix of m rows and n columns, one row at a time (n elements). A signal is applied.

To the terminals _{Doy1 to Doyn} , a modulation signal for controlling the output electron beam of each element of the surface conduction electron-emitting device in one row selected by the scanning signal is applied. The high-voltage terminal Hv is connected to the DC voltage source Va, for example, by one.
A DC voltage of 0 kV is supplied, which is an accelerating voltage for applying sufficient energy to the electron beam emitted from the surface conduction electron-emitting device to excite the phosphor.

The scanning circuit 142 will be described. Scanning circuit 142 are those having the m-number of switching devices therein (in the figure, is schematically shown in S ₁ to S _m).
Each switching element selects either the output voltage of the DC voltage source Vx or 0 V (ground level),
The terminals D _{ox1 to} D _oxm of the image forming apparatus 141 are electrically connected. Each switching element S ₁ to S _m, which operates based on a control signal T _scan control circuit 143 outputs, it can be configured by combining switching elements such as FET.

In the case of the present embodiment, the DC voltage source Vx is based on the characteristics (electron emission threshold voltage) of the surface conduction electron-emitting device, and the driving voltage applied to the non-scanned device is the electron emission threshold. It is set to output a constant voltage that is equal to or lower than the value voltage.

The control circuit 143 has a function of matching the operation of each unit so that appropriate display is performed based on an image signal input from the outside. This control circuit 143
Is the synchronization signal T sent from the synchronization signal separation circuit 146.
Based on the _sync , T _scan and T _sft and T _mry control signals are generated for each unit.

The synchronizing signal separating circuit 146 is a circuit for separating a synchronizing signal component and a luminance signal component from an NTSC television signal input from the outside, and uses a general frequency separating (filter) circuit or the like. Can be configured. The synchronizing signal separated by the synchronizing signal separating circuit 146 includes a vertical synchronizing signal and a horizontal synchronizing signal, but is shown here as a _Tsync signal for convenience of explanation. The luminance signal component of the image separated from the television signal is represented as a DATA signal for convenience. This DATA signal is input to the shift register 144.

The shift register 144 is for serially / parallel converting the DATA signal input serially in time series for each line of an image. The shift register 144 converts the DATA signal into a control signal _Tsft sent from the control circuit 143. (Ie, the control signal _Tsft is a shift clock of the shift register 144).
The data for one line of the serial / parallel-converted image (corresponding to the drive data for n electron-emitting devices) is I _d1
To _{Idn as} the n parallel signals.
4 is output.

The line memory 145 is a storage device for storing data for one line of an image for a required time.
In accordance with the control signal T _mry sent from the control circuit 143 stores the contents of the appropriate I _d1 ~I _dn. The stored contents are output as I _{d′ 1 to} I _{d′ n} , and the modulated signal generator 1
47 is input.

The modulation signal generator 147 outputs the image data I
_d'1 is ~I signal source for properly driving modulating each of the surface conduction electron-emitting device according to each of _d'n, the output signal through a terminal _D oy1 ~D oyn, an image forming apparatus 141 is applied to the surface conduction electron-emitting device.

As described above, the electron-emitting device to which the present invention can be applied has the following basic characteristics with respect to the emission current _Ie . That is, a clear threshold voltage V is required for electron emission.
_th There is, only electron emission when it is applied to the V _th or more of voltage occurs. For a voltage equal to or higher than the electron emission threshold, the emission current also changes according to the change in the voltage applied to the device. From this, when applying a pulsed voltage to this element,
For example, when a voltage lower than the electron emission threshold is applied, electron emission does not occur, but when a voltage higher than the electron emission threshold is applied, an electron beam is output. At this time, by varying the peak value V _m of pulse, it is possible to control the intensity of the output electron beam. Also, the pulse width P
By changing _w , it is possible to control the total amount of charges of the output electron beam.

Accordingly, as a method of modulating the electron-emitting device according to the input signal, a voltage modulation method, a pulse width modulation method, or the like can be adopted. When implementing the voltage modulation method, a circuit of a voltage modulation method that generates a voltage pulse of a fixed length and modulates the peak value of the pulse appropriately according to input data is used as the modulation signal generator 147. be able to.

When implementing the pulse width modulation method,
As the modulation signal generator 147, a pulse width modulation type circuit that generates a voltage pulse having a constant peak value and appropriately modulates the width of the voltage pulse according to input data can be used.

The shift register 144 and the line memory 14
5 can be a digital signal type or an analog signal type. This is because the serial / parallel conversion and storage of the image signal may be performed at a predetermined speed.

When the digital signal type is used, it is necessary to convert the output signal DATA of the synchronization signal separation circuit 146 into a digital signal. For this purpose, an A / D converter is provided at the output of the synchronization signal separation circuit 146. Just do it. In this connection, the circuit used for the modulation signal generator 147 differs slightly depending on whether the output signal of the line memory 145 is a digital signal or an analog signal. That is, in the case of the voltage modulation method using a digital signal, the modulation signal generator 14
For example, a D / A conversion circuit is used in 7 and an amplification circuit and the like are added as necessary. In the case of the pulse width modulation method, the modulation signal generator 147 includes, for example, a high-speed oscillator and a counter for counting the number of waves output from the oscillator, and a comparison for comparing the output value of the counter with the output value of the memory. The circuit which combined the device (comparator) is used. If necessary, an amplifier for voltage-amplifying the pulse width modulated signal output from the comparator to the drive voltage of the surface conduction electron-emitting device can be added.

In the case of the voltage modulation method using an analog signal, an amplification circuit using, for example, an operational amplifier can be employed as the modulation signal generator 147, and a level shift circuit and the like can be added as necessary. In the case of the pulse width modulation method, for example, a voltage-controlled oscillation circuit (VOC) can be employed, and an amplifier for amplifying the voltage up to the drive voltage of the surface conduction electron-emitting device can be added as necessary.

In the image forming apparatus of the present invention which can have such a configuration, each of the electron-emitting devices is provided with a terminal D outside the container.
_ox1 to D _oxm, by applying a voltage via the _D oy1 ~D oyn, electron emission occurs. And the high voltage terminal Hv
A high voltage is applied to the metal back 8 via the, and the electron beam is accelerated. The accelerated electrons collide with the fluorescent film 7 and emit light to form an image.

The configuration of the image forming apparatus described here is an example of an image forming apparatus to which the present invention can be applied, and various modifications can be made based on the technical idea of the present invention. For example, the input signal is described in the NTSC system. However, the input signal is not limited to the NTSC system. In addition to the PAL and SECAM systems, a TV signal including a larger number of scanning lines (for example, MUSE system and the like) High-definition TV system).

The image forming apparatus of the present invention can be used as a display device for a television broadcast, a display device such as a video conference system or a computer, or an image forming device as an optical printer using a photosensitive drum or the like. Can be used.

[0080]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to preferred examples, but the present invention is not limited to these examples, and each element within a range in which the object of the present invention is achieved. This also includes those in which substitutions or design changes have been made.

<Embodiment 1> An image forming apparatus inspected and prepared by the pressure inspection method inside the image forming apparatus according to the present embodiment has the same configuration as the apparatus schematically shown in FIG. , A plurality (100 rows × 300 columns) of surface conduction electron-emitting devices are arranged in a simple matrix wiring.

FIG. 3 shows a plan view of a part of the electron source 1. FIG. 4 is a sectional view taken along the line AA 'in FIG. In FIGS. 3 and 4, members having the same functions are denoted by the same reference numerals and described.

Here, 51 is an electron source substrate, 52 is an X-direction wiring corresponding to _Doxm in FIG. 1, 53 is a Y-direction wiring corresponding to _Doyn in FIG. 1, 54 is a surface conduction electron-emitting device,
5 is a non-evaporable getter, 61 is an interlayer insulating layer, 62 and 63 are device electrodes, 64 is a conductive film including an electron emission portion, and 65 is a device for electrically connecting the device electrode 63 and the Y-direction wiring 53. It is a contact hole.

FIGS. 1, 2, 5, and 6 show a method of manufacturing and an inspection method of the image forming apparatus according to the present embodiment.
This will be described with reference to FIG. Step-a 5 nm-thick Cr and 600 nm-thick Au were sequentially laminated by vacuum evaporation on an electron source substrate 51 in which a 0.5 μm-thick silicon oxide film was formed on a cleaned blue plate glass by a sputtering method. Thereafter, a photoresist (AZ1370 Hoechst) is spin-coated with a spinner and baked, and then a photomask image is exposed and developed to form a Y-directional wiring 5.
A resist pattern 3 is formed, and the Au / Cr deposited film is wet-etched to form a Y-directional wiring 53 having a desired shape (FIG. 5A). Step-b Next, an interlayer insulating layer 61 made of a silicon oxide film having a thickness of 1.0 μm is deposited by an RF sputtering method (FIG. 5).
(B)). Step-c A photoresist pattern for forming the contact hole 65 is formed in the silicon oxide film deposited in the step b, and the interlayer insulating layer 61 is etched using the photoresist pattern as a mask to form the contact hole 65. Etching is CF
RIE (Reactive Io) using ₄ and H ₂ gas
n Etching) method (FIG. 5 (c)). Step-d After that, a pattern to be the element electrodes 62 and 63 and the element electrode interval G is formed by a photoresist (RD-200N-41).
Hitachi Chemical Co., Ltd.) and a thickness of 5 n
m of Ti and 100 nm of Ni were sequentially deposited. The photoresist pattern was dissolved with an organic solvent, the Ni / Ti deposited film was lifted off, and the device electrodes 62 and 63 were formed with the device electrode interval G of 3 μm and the device electrode width of 300 μm (FIG. 5D). Step-e After forming a photoresist pattern of the X-direction wiring 52 on the device electrodes 62 and 63, 5 nm thick Ti and 500 nm thick Au are sequentially deposited by vacuum deposition, and unnecessary Remove the part to get the desired shape of X
The direction wiring 52 was formed (FIG. 6E). Step-f A Cr film 66 having a thickness of 100 nm is deposited and patterned by vacuum evaporation, and a Pd amine complex solution (ccp
4230 Okuno Pharmaceutical Co., Ltd.) was spin-coated with a spinner and heated and baked at 300 ° C. for 10 minutes.

Further, the thus formed conductive film 64 for forming an electron emitting portion composed of fine particles composed of Pd as a main element has a thickness of 8.7 nm and a sheet resistance of 3.2 × 1.
0 was ^{4 Ω} / □. (FIG. 6 (f)). Step-g A desired pattern was formed by etching the Cr film 66 and the conductive film 64 for forming the electron emission portion after firing with an acid etchant (FIG. 6G). Step-h A pattern is formed such that a resist is applied to portions other than the contact hole 65, and a 5 nm-thick T
i, Au having a thickness of 500 nm was sequentially deposited. Unnecessary portions were removed by lift-off to bury the contact holes 65 (FIG. 6H).

Through the above steps, a plurality (100 rows × 300 columns) of conductive films 64 for forming electron-emitting portions are formed on the electron source substrate 51 by simple matrix wiring using the X-directional wiring 52 and the Y-directional wiring 53. An electron source 1 was formed. Step-i Next, a face plate 4 serving as an image display portion was prepared. In the face plate 4, a transparent electrode (not shown) made of ITO was provided on the glass substrate 6 in order to increase the conductivity of the fluorescent film 7. The fluorescent film 7 serving as an image forming member is a stripe-shaped phosphor (see FIG. 7A) in order to realize a color, a black stripe is formed first, and each color is formed by a slurry method in a gap. The phosphors 72R, 72G, and 72B were applied to form the phosphor film 7. As a material for the black stripe, a material mainly containing graphite, which is commonly used, was used.

Further, a metal back 8 was provided on the inner surface side of the fluorescent film 7. The metal back 8 was manufactured by performing a smoothing process (usually called filming) on the inner surface of the fluorescent film 7 after the fluorescent film 7 was manufactured, and then performing vacuum deposition of Al. Step-j Next, a non-evaporable getter was formed on the Y-directional wiring 53. The formation of the non-evaporable getter was performed by a thermal spraying method using a normal photolithography technique. In the thermal spraying, the electron source substrate 51 is mounted in a reduced-pressure plasma thermal spraying apparatus (7MC type manufactured by Sulzer Metco) and an alloy of a non-evaporable getter material (Zr (75%)-V (20%)-Fe (5%)) Powder # 325 mesh) was sprayed. At this time, the pressure inside the pressure reducing tank is temporarily reduced to 1.3 × 10 Pa, and then A
Thermal spraying was performed by setting the pressure in the tank to 4.7 × 10 ³ Pa with r gas. After the thermal spraying, the pressure in the tank was again reduced to 1.3 × 10 Pa, and then nitrogen gas was introduced to the atmospheric pressure. After the temperature of the non-evaporable getter was sufficiently lowered, the tank was opened to the atmosphere and taken out. The thickness of the formed getter material was about 40 μm on average. Step-k Next, the envelope 5 shown in FIG. 2 was manufactured by the following procedure.

The electron source 1 created by the above-described steps
The support frame 3, the shield 9, the ring-type evaporable getter 10, and the face plate 4 are combined, and the positions of the electron source 1 and the phosphors of each color of the face plate 4 are strictly adjusted. Was formed. The sealing method is as follows: frit glass is applied to the joint portion, and calcined at 300 ° C. in the air.
Heat treatment was performed at 0 ° C. for 10 minutes to perform bonding.

Before describing the next step, the vacuum processing apparatus and inspection apparatus used in the subsequent steps will be described with reference to FIG.

In FIG. 1, reference numeral 42 denotes a gate valve, which separates the side of the image forming apparatus 30 (area A in the figure) from the other vacuum processing system and gas introduction control system (area B in the figure). . By exchanging the A area, the system in the B area
It can be used for other image forming apparatuses. 31 is an exhaust pipe. Further, the vacuum chamber 32 is connected to a gate valve 33, and the gate valve 33 is connected to the exhaust device 3.
4. The exhaust device 34 is configured by a backup dry pump connected to a magnetic levitation type turbo molecular pump via a valve (not shown).

The vacuum chamber 32 has a pressure gauge 35 for monitoring the internal pressure and a quadrupole mass spectrometer (Q-ma) for monitoring the gas partial pressure inside the vacuum chamber 32.
ss) 36 is provided. Furthermore, vacuum chamber 3
Numeral 2 is connected to an ampule 40 and a cylinder 41 in which an introduced substance source 39 is sealed, via a gas introduction line 37 and a gas introduction control device 38 provided in the middle of the gas introduction line 37. In the present embodiment, a variable leak valve compatible with ultra-high vacuum was used as the gas introduction control device 38, and the ampoule 40 was equipped with acetone (CH ₃ ) ₂ CO. The following steps were performed using the above vacuum processing apparatus and inspection apparatus. Step-1 The gas in the envelope 5 completed in the previous step is exhausted by the exhaust device 34 through the exhaust pipe 31 and the vacuum chamber 32, and reaches about 1 × 10 ⁻³ Pa as indicated by the pressure gauge 35. After that, FIG.
The forming was performed using the apparatus shown in FIG.

FIG. 8 is a schematic view of an apparatus for applying a voltage to an image forming apparatus under a manufacturing process in a forming process. In this embodiment, the device is also used in an activation process which is a subsequent process.

As shown in FIG. 8, in the image forming apparatus 30 under the manufacturing process, the Y-direction wirings D _{y1 to} D _yn are commonly connected and connected to the ground, while the X-direction wirings D _{x1 to} D _xm are Each is connected to a corresponding terminal of the switching box 104. Reference numeral 101 denotes a control device, which is a pulse generator 10.
2. The switching box 104 is controlled through a control signal bus, and the measured value measured by the ammeter 103 is obtained through a measurement data transfer bus.

The switching box 104 selects one line from the X-direction wirings D _{x1 to} D _xm , and _supplies the selected line to the pulse generator 102 through the ammeter 103.
Is applied. The unselected lines are connected to the ground potential by the switching box 104. The forming process was performed for each element row in the X direction (300 elements).

The waveform of the applied pulse was a rectangular wave pulse as shown in FIG. 9A, and the peak value (peak of the voltage difference between the device electrodes) was gradually increased from 0V. Note that the pulse width T ₁ = 1 msec and the pulse interval T ₂ = 10 msec.

Further, a peak value of 0.1 is applied between rectangular wave pulses.
A rectangular wave pulse of V was inserted (FIG. 9B), and the resistance of each row was measured by measuring the current. 3.3k resistance
When it exceeded Ω (1 MΩ per element), the forming of that row was terminated, and the process proceeded to the next row. This process is performed for all the rows to complete the forming of all the conductive films (the conductive films 64 for forming the electron emission portions), to form the electron emission portions in each of the conductive films, and to form a plurality of surface conduction type electrons. An electron source 1 in which emission elements were wired in a simple matrix was prepared. Step-m Next, acetone (CH ₃ ) ₂ CO
And adjusted so that the indicated value of the pressure gauge 35 becomes about 2 × 10 ⁻³ Pa. At that time, it is confirmed that the gas molecules of acetone are surely introduced into the vacuum chamber 32 by using the Q-mass 36.

Thereafter, similar to the forming step, FIG.
By applying a pulse voltage through each of the X-direction wirings using the device described above, the activation process of each electron-emitting device was performed. The pulse waveform generated by the pulse generator 102 is
The rectangular wave shown in FIG. 9A has a peak value of 15 V, a pulse width T ₁ = 1 msec, and a pulse interval of 100 msec. The switching box 104, repeating to switch sequentially select line for each 1msec to D _x1 to D _x100, this result, in each element row, T ₁ = 1mse
c, a rectangular wave of T ₂ = 100 msec is applied with the phase slightly shifted for each row (FIG. 10).

The ammeter 103 is used in a mode for detecting the current value in the ON state of the rectangular wave pulse (when the voltage is 15 V), and the average of the current value in each element row is 600 mA (2 mA per element). ), The pulse application was terminated, the inside of the envelope 5 was evacuated, and the activation process was terminated. Step-n It is assumed that the whole of the image forming apparatus 30 and the vacuum vessel 32 is maintained at 200 ° C. for 5 hours by a heating device (not shown) while being evacuated, and is adsorbed on the envelope 5 and the inner wall of the vacuum chamber 32. Possible (CH ₃ ) ₂ CO and its decomposition products were once evacuated.

Then, the whole container was heated at 350 ° C. for about 10 hours.

Thereafter, the exhaust pipe was heated with a burner and sealed off. Subsequently, the evaporable getter 10 previously set outside the image display area was flashed by high-frequency heating. Step-o For the completed image forming apparatus, the color of the surface of the non-evaporable getter 2 formed on the wiring in the Y direction from the observation window 16 provided in advance using a small CCD camera (not shown). Was inspected. In such a case, the surface of the non-evaporable getter 2 became dark black and exceeded the threshold value of the data value (brightness and lightness) of the image held in the storage area inside the inspection device. The pressure inside the device was determined to be abnormal. Therefore, the image forming apparatus was determined to be defective.

<Embodiment 2> In the step-n in the embodiment 1, the entire image forming apparatus 30 and the vacuum vessel 32 are kept at 200 ° C. for 5 hours by a heating device (not shown) while the evacuation is continued. (CH ₃ ) ₂ CO and its decomposition products, which are considered to be adsorbed on the inner wall of the envelope 5 and the vacuum chamber 32, were once evacuated. Then, the entire container was heated at 350 ° C. for about 10 hours.

Thereafter, the exhaust pipe was heated with a burner and sealed off. Subsequently, the evaporable getter 10 previously set outside the image display area was flashed by high-frequency heating.

The reflection of the surface of the non-evaporable getter 2 formed on the Y direction wiring from the observation window 16 provided in advance to the completed image forming apparatus by using a small CCD camera (not shown). The light intensity was monitored. In such a case, the surface of the non-evaporable getter 2 becomes dark black and becomes smaller than the data value of the reflected light intensity held in the storage area inside the inspection device, so that the inspection device reduces the pressure inside the image forming device. It was determined to be abnormal. Therefore, the present image forming apparatus
It was determined to be defective.

[0104]

As described above, according to the image forming apparatus and the pressure inspection method inside the image forming apparatus of the present invention,
Before the image forming apparatus is completed, simple matrix driving or the like is performed to detect the state of the pressure in the image forming apparatus without displaying the entire image.

Further, according to the pressure inspection method of the present invention, the components inside the image forming apparatus can be used by using the components of the image forming apparatus without adding a new special inspection mechanism to the conventional assembling process. Since the pressure is detected, there is no need to make any change to the process of forming the conventional image forming apparatus. Thereby, the yield of the image forming apparatus has been improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an outline of a vacuum processing apparatus and an inspection apparatus used for manufacturing and inspecting an image forming apparatus.

FIG. 2 is a perspective view showing the structure of the image forming apparatus of the present invention.

FIG. 3 is a schematic diagram for explaining an arrangement relationship between an electron source and a non-evaporable getter according to the present invention.

FIG. 4 is a sectional view taken along line A-A 'of the electron source shown in FIG.

FIG. 5 is a schematic view for explaining a manufacturing process of the electron source shown in FIG.

FIG. 6 is a schematic view for explaining a manufacturing process of the electron source shown in FIG.

FIG. 7 is a schematic diagram for explaining a structure of a fluorescent film.

FIG. 8 is a schematic diagram illustrating a configuration of an apparatus used for a manufacturing process, a forming process, and an activation process of the image forming apparatus.

FIG. 9 is a diagram illustrating an example of a pulse voltage waveform applied to a forming process.

FIG. 10 is a diagram showing a pulse voltage waveform applied to each X-direction wiring and a temporal relative relationship during an activation process.

FIG. 11 is a schematic diagram showing a configuration of an electron source having a matrix wiring electron source used for explaining a conventional technique.

FIG. 12 is a schematic diagram showing an example of an image forming apparatus using the electron source of FIG.

FIG. 13 is a schematic plan view (A) and a schematic cross-sectional view (B) showing the configuration of a surface conduction electron-emitting device used in the description of the conventional technique.

FIG. 14 is a block diagram illustrating a configuration example of a driving circuit for performing television display based on an NTSC television signal by an image forming apparatus configured using an electron source in a matrix arrangement.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electron source 2 Non-evaporable getter 3 Support frame 4 Face plate 5 Enclosure 6 Glass substrate 7 Fluorescent film 8 Metal back 9 Shield 10 Evaporative getter 11 Row selection terminal 11 'X-direction wiring 12 Signal input terminal 12' Y direction wiring 13 Surface conduction electron-emitting device 14 Electron source substrate 15 Rear plate 16 Observation window 17 Detecting means 30 Image forming apparatus 31 Exhaust pipe 32 Vacuum chamber 33 Gate valve 34 Exhaust device 35 Pressure gauge 36 Q-Mass 37 Gas introduction line Reference Signs List 38 gas introduction control device 39 introduction material source 40 ampule 41 cylinder 42 gate valve 51 electron source substrate 52 X-direction wiring 53 Y-direction wiring 54 surface conduction electron-emitting device 55 non-evaporable getter 56 connection 61 interlayer insulating layer 62, 63 device Electrode 64 Conductive film including electron-emitting portion 65 Contact Hole 66 Cr film 71 Black conductive material 72R, 72B, 72G Phosphor 101 Control device 102 Pulse generator 103 Ammeter 104 Switching box 131 Substrate 132, 133 Element electrode 134 Conductive thin film 135 Electron emission section 141 Display panel 142 Scanning circuit 143 Control circuit 144 Shift register 145 Line memory 146 Synchronous signal separation circuit 147 Modulated signal generator

Claims (12)

[Claims] 1. An electron source having a plurality of electron-emitting devices disposed on a substrate in an envelope, an image forming member disposed to face the substrate, and a degree of vacuum in the envelope. An image forming apparatus having a getter material for maintaining the image quality, wherein a pressure detecting unit for detecting a pressure in the image forming apparatus based on a change in a surface color of the getter material is provided. Forming equipment. 2. An electron source having a plurality of electron-emitting devices disposed on a substrate in an envelope, an image forming member disposed to face the substrate, and a degree of vacuum in the envelope. An image forming apparatus having a getter material for maintaining the pressure, wherein a pressure detecting means for detecting a pressure inside the image forming apparatus based on a change in a surface color of the non-evaporable getter material formed by a thermal spraying method. An image forming apparatus, comprising: 3. The image forming apparatus according to claim 2, wherein a CCD camera, a video camera, or the like is used as an observation unit for observing a change in surface color of the non-evaporable getter material. 4. The image forming apparatus according to claim 2, wherein the thickness of the non-evaporable getter material formed by the thermal spraying method is 10 to 100 μm. 5. The image forming apparatus according to claim 1, wherein said electron source is an electron source in which a plurality of electron-emitting devices arranged in a matrix are arranged on a substrate. apparatus. 6. The image forming apparatus according to claim 1, wherein said electron source has a surface conduction electron-emitting device. 7. An electron source in which a plurality of electron-emitting devices are disposed on a substrate in an envelope, an image forming member disposed to face the substrate, and a degree of vacuum in the envelope. A method for inspecting the pressure inside an image forming apparatus having a getter material for maintaining the pressure, wherein the pressure inside the image forming apparatus is detected based on a change in a surface color of the getter material. Pressure inspection method inside the image forming apparatus. 8. An electron source in which a plurality of electron-emitting devices are disposed on a substrate in an envelope, an image forming member disposed to face the substrate, and a degree of vacuum in the envelope. A method for inspecting the pressure inside an image forming apparatus having a getter material for maintaining the pressure, wherein based on a change in the surface color of the non-evaporable getter material formed by a thermal spray method, A pressure inspection method inside an image forming apparatus, comprising detecting pressure. 9. The pressure inspection inside the image forming apparatus according to claim 8, wherein a CCD camera, a video camera, or the like is used as an observation unit for observing a change in the surface color of the non-evaporable getter material. Method. 10. The method according to claim 8, wherein the thickness of the non-evaporable getter material formed by the thermal spraying method is 10 to 100 μm. 11. The image forming apparatus according to claim 7, wherein said electron source is an electron source in which a plurality of electron-emitting devices arranged in a matrix are arranged on a substrate. How to check the pressure inside the device. 12. The pressure inspection method according to claim 7, wherein the electron source includes a surface conduction electron-emitting device.