JP3226428B2 - Image forming device - Google Patents

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 using an electron source.

[0002]

2. Description of the Related Art Conventionally, two types of electron emitting devices, a thermionic electron source and a cold cathode electron source, are known. The cold cathode electron source includes a field emission type (hereinafter abbreviated as FE type), a metal / insulating layer / metal type (hereinafter abbreviated as MIM type), and a surface conduction type electron emission element.

[0003] An example of the FE type is WP Dyke & WW Do
lan, “Filed emission”, Advancein Electron Physic
s, 8 89 (1956) or CA Spindt, “Physical Prope
rties of thin-film field emission cathodes with mo
lybdenium ", J. Appl. Phys., 47 5248 (1976).

[0004] CA Mead, "The
tunnel-emission amplifier ”, J. Appl. Phys., 32 64
6 (1961) are known.

Examples of the surface conduction electron-emitting device type include:
MI Elinson, Radio Eng. Electron Phys., 10 (1965)
Etc.

[0006] The surface conduction electron-emitting device utilizes the phenomenon that electron emission occurs when a current flows through a small-area thin film formed on a substrate in parallel with the film surface. Examples of the surface conduction electron-emitting device include a device using an SnO ₂ thin film by Elinson et al. And a device using an Au thin film [G. Dittmer: “Thin Solid Films”, 9 317 (1972)].
, In ₂ O ₃ / SnO ₂ thin film [M. Hartwell
and CG Fonstad: “IEEE Trans. ED Conf.”, 519
(1975)], and those using a carbon thin film [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1, p. 22, page (1983)] and the like have been reported.

As a typical device configuration of these surface conduction electron-emitting devices, the above-mentioned M.D. FIG. 15 shows a device configuration of the Hartwell. In FIG. 1, reference numeral 1 denotes a substrate. Reference numeral 4 denotes a conductive thin film, which is formed of a metal oxide thin film or the like formed by sputtering in an H-shape, and the electron emission portion 5 is formed by an energization process called energization forming described later. In the drawing, the element electrode interval L is 0.5 to 1 mm, and W ′ is 0.1
mm. Since the position and shape of the electron-emitting portion 5 are unknown, they are shown as schematic diagrams.

Conventionally, in these surface conduction electron-emitting devices, the electron-emitting portion 5 is subjected to an energization process called energization forming in advance before the electron emission.
It was common to form That is, energization forming means applying a DC voltage or a very slowly increasing voltage, for example, about 1 V / min, to both ends of the conductive thin film 4 and energizing the conductive thin film 4 to locally destroy, deform or alter the conductive thin film. The purpose is to form the electron-emitting portion 5 in a state of high resistance. In the electron emitting portion 5, a crack is generated in a part of the conductive thin film 4, and electrons are emitted from the vicinity of the crack. The surface conduction type electron-emitting device that has been subjected to the energization forming process causes the electron-emitting portion 5 to emit electrons by applying a voltage to the conductive thin film 4 and causing a current to flow through the device.

The above-mentioned surface conduction electron-emitting device has an advantage that a large number of devices can be arranged and formed over a large area because of its simple structure and easy manufacture. Therefore, various applications that can take advantage of this feature are being studied. For example, a display device such as a charged beam source and an image forming apparatus may be used.

FIG. 17 is a sectional view showing the structure of a conventional flat plate type image forming apparatus. In FIG. 17, reference numeral 1 denotes a substrate on which an electron-emitting device group (not shown) is mounted, and a face plate 6 on which an image forming member (not shown) is mounted is disposed to face the substrate 1. Substrate 1 and face plate 6
The support frame 12 disposed therebetween is sealed and fixed by the frit glass 7 to form the display panel 121. The internal pressure of the image forming apparatus in FIG. 17 is maintained at a vacuum of about 10 ⁻⁶ Torr.

In the image forming apparatus having such a structure, a temperature difference occurs between the face plate 6, the substrate 1, and the support frame 12 due to the heat generated by the electron-emitting device and the metal back formed on the face plate. In addition, there is a possibility that a color shift, a decrease in luminance, a screen distortion, or the like may occur due to a difference in a thermal expansion amount. Conventionally, to solve this problem, FIG.
6, heat is radiated from the substrate using a radiator (a heat sink substrate, a radiating fin).
-196782).

[0012]

However, the amount of heat radiation generally has a relationship proportional to the temperature difference between the radiator temperature and the ambient temperature, and the surface area of the radiator. There was a problem that it was difficult to increase the surface area due to restrictions.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a high-definition image forming apparatus which can reduce the temperature difference between members and effectively eliminate color shift. I have.

[0014]

In order to achieve the above object, the present invention provides an electron source substrate on which an electron-emitting device group is mounted;
A face plate on which an image forming member on which an image is formed by irradiating an electron beam emitted from the electron-emitting device group is arranged facing the electron source substrate, the electron source substrate and the face plate; An image forming apparatus having at least a display panel including a support frame disposed between peripheral portions of the electron source substrate, a heat conductive member having a higher thermal conductivity than the electron source substrate, the support frame, and the face plate. And an outer surface of the support frame, and an image forming apparatus provided along the outer surface of the face plate excluding the display unit, wherein the heat conducting member is attached or integrally formed with a radiator. Fins are provided on the radiator so that the longitudinal direction of the fins coincides with the vertical direction of the image forming apparatus. The radiator uses convection heat transfer, the radiator of the radiator uses forced convection heat transfer, and a gap between the heat conducting member and the electron source substrate, the face plate, and the support frame. And an electron-emitting device group is a surface conduction electron-emitting device.

[0015]

According to the image forming apparatus of the present invention, the heat is efficiently conducted from the high temperature section to the low temperature section through the heat conduction member, and the temperature difference between the high temperature section and the low temperature section is reduced. Unlike the conventional method of reducing the temperature difference by releasing the heat from the high temperature part, the temperature difference between the members can be effectively reduced.

Further, the amount of heat radiation can be made equal to or more than that of the conventional method. As a result, a temperature difference between the members is reduced, and an image forming apparatus having a high-definition display panel with less color shift can be obtained.

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

FIG. 1 is a sectional view of an image forming apparatus showing an embodiment of the present invention. In FIG. 1, reference numeral 6 denotes a face plate on which an image forming member (not shown) is mounted, and 91 denotes an electron-emitting device group ( (Not shown). Reference numeral 12 denotes the face plate 6 and the electron source substrate 91.
, And each member is sealed and fixed by frit glass 7 to form a vacuum container.

Reference numeral 8b denotes a heat conducting member for equalizing the temperature on the electron source substrate 91. The heat conducting member 8b is brought into close contact with the electron source substrate along the bottom and side surfaces of the electron source substrate 91 to improve heat conduction from the substrate. ing. 8a efficiently transfers heat generated in the electron source substrate 91 to the support frame 12 and the face plate 6, thereby reducing temperature unevenness between members such as the electron source substrate 91, the face plate 6, and the support frame 12. It is a heat conducting member to be made. It is desirable that the heat conductive members 8 a and 8 b are members whose heat conductivity is higher than the heat conductivity of the electron source substrate 91, the face plate 6 and the support frame 12.

Further, the heat conductive members 8a and 8b are integrally formed, the electron source substrate 91, the face plate 6
And a display panel comprising a support frame 12 and a heat conducting member 8a,
It is preferable that a heat conductive paste is applied to the contact surface with 8b because the heat resistance is reduced. In order to improve the heat radiation effect and reduce the absolute temperature, a heat radiator (not shown) may be attached to the heat conducting member, or may be integrally formed.

Further, the cold cathode electron source used in the present invention has a simple structure, and is preferably a surface conduction electron-emitting device which can be easily manufactured.

There are basically two types of surface conduction electron-emitting devices that can be used in the present invention, a planar surface conduction electron-emitting device and a vertical surface conduction electron-emitting device.

FIG. 4 is a schematic plan view and a sectional view showing the structure of a basic surface conduction electron-emitting device.

In FIG. 4, 1 is a substrate, 2 and 3 are device electrodes, 4 is a conductive thin film, and 5 is an electron emitting portion.

As the substrate 1, quartz glass, glass having a low impurity content such as Na, blue plate glass, a glass substrate having SiO ₂ formed on its surface, and a ceramic substrate such as alumina are used. As a material for the device electrodes 2 and 3, a general conductor is used. For example, Ni, Cr, Au, Mo,
Printed conductors composed of metals or alloys such as W, Pt, Ti, Al, Cu, Pd and the like, and metals or metal oxides such as Pd, Ag, Au, RuO ₂ , Pd—Ag and glass, In ₂ O ₃ is appropriately selected from a transparent conductive material such as -SnO ₂ and semiconductor materials such as polysilicon.

The element electrode interval L is preferably from several hundred angstroms to several hundred micrometers. Further, it is desirable that the voltage applied between the device electrodes is low, and a preferable device electrode interval is required to be several tens to several tens of micrometers because it is required to produce the device with good reproducibility. The length W of the device electrode is preferably from several micrometers to several hundred micrometers in view of the resistance value and the electron emission characteristics of the electrode, and the film thickness of the device electrodes 2 and 3 is preferably several micrometers to more than several hundred angstroms. In addition to the configuration shown in FIG. 4, a configuration in which the conductive thin film 4 and the electrodes of the device electrodes 2 and 3 are sequentially formed on the substrate 1 may be adopted.

The conductive thin film 4 is particularly preferably a fine particle film composed of fine particles in order to obtain good electron emission characteristics. The film thickness is determined by the step coverage to the device electrodes 2 and 3 and the resistance between the device electrodes 2 and 3. It is set as appropriate depending on the value and the energizing forming conditions to be described later, but is preferably from several angstroms to several thousand angstroms, particularly preferably from 10 angstroms to 500 angstroms. The sheet resistance is 10 ^{3 to} 10 ⁷ Ω / □.

The material constituting the conductive thin film 4 is P
d, Pt, Ru, Ag, Au, Ti, In, Cu, C
metals such as r, Fe, Zn, Sn, Ta, W, Pb, Pd
Oxides such as O, SnO ₂ , In ₂ O ₃ , PbO, Sb ₂ O ₃ , HfB ₂ , ZrB ₂ , LaB ₆ , CeB ₆ , YB
_4, GdB boride such as _{4, TiC, ZrC, HfC,} T
carbides such as aC, SiC, WC, TiN, ZrN, Hf
Examples include nitrides such as N, semiconductors such as Si and Ge, and carbon.

The fine particle film described here is a film in which a plurality of fine particles are gathered, and has a fine structure not only in a state where the fine particles are individually dispersed and arranged, but also in a state where the fine particles are adjacent to each other or overlap each other (an island). (Including the shape). The particle size of the fine particles is from several angstroms to thousands of angstroms, preferably from 10 angstroms to 200 angstroms.

The electron-emitting portion 5 is a high-resistance crack formed in a part of the conductive thin film 4 and is formed by energization forming or the like. The crack may have conductive fine particles having a particle size of several Angstroms to several hundred Angstroms. The conductive fine particles contain at least some of the elements constituting the conductive thin film 4. Further, the electron emitting portion 5 and the conductive thin film 4 in the vicinity thereof may include carbon and a carbon compound. FIG. 5 is a schematic diagram showing the configuration of a basic vertical surface conduction electron-emitting device. 5, the same members as those in FIG. 4 are denoted by the same reference numerals. 51 is a step forming part. The substrate 1, the device electrodes 2 and 3, the conductive thin film 4, and the electron emitting portion 5 can be made of the same material as that of the above-mentioned flat surface conduction type electron emitting device. The step forming portion 51 is made of an insulating material, and the film thickness of the step forming portion 51 corresponds to the element electrode interval L of the flat surface conduction electron-emitting device described above. The spacing is from tens of micrometers to hundreds of angstroms. The distance can be controlled by the manufacturing method of the step forming portion and the voltage applied between the device electrodes, but is preferably from several hundred angstroms to several micrometers.

The conductive thin film 4 is laminated on the device electrodes 2 and 3 so as to be formed after the device electrodes 2 and 3 and the step forming portion 51 are formed. In FIG. 5, the electron emitting portion 5 is shown as being formed linearly on the step forming portion 51, but the shape and position are not limited to this depending on the forming conditions, energizing forming conditions, and the like. Absent.

Various methods are conceivable as a method of manufacturing the above-mentioned surface conduction electron-emitting device. One example is shown in FIG.

Hereinafter, a method of manufacturing the electron source substrate will be described with reference to FIGS. The same members as those in FIG. 4 are denoted by the same reference numerals.

1) After sufficiently washing the substrate with a detergent, pure water and an organic solvent, a device electrode material is deposited by a vacuum evaporation method, a sputtering method or the like. Thereafter, device electrodes 2 and 3 are formed on the substrate by a photolithography technique (FIG. 6).
(A)).

2) An organometallic solution is applied to the substrate 1 on which the device electrodes 2 and 3 are provided and left to form an organometallic thin film. The organometallic solution here is a solution of an organometallic compound containing the above-mentioned metal forming the conductive film 4 as a main element. Thereafter, the organic metal thin film is heated and baked, and is patterned by lift-off, etching, or the like to form the conductive thin film 4 (FIG. 6B). Here, the description has been given of the method of applying the organometallic solution, but the present invention is not limited to this, and the method is formed by a vacuum deposition method, a sputtering method, a chemical vapor deposition method, a dispersion coating method, a dipping method, a spinner method, or the like. There is also.

3) Subsequently, an energization process called energization forming is performed. The energization forming is to energize a power supply (not shown) between the element electrodes 2 and 3 to locally destroy, deform or alter the conductive thin film 4 to form a portion having a changed structure. The portion where the structure is locally changed is referred to as an electron emitting portion 5 (FIG. 6C). FIG. 7 shows an example of the voltage waveform of the energization forming.

The voltage waveform is particularly preferably a pulse waveform. When a voltage pulse having a constant pulse peak value is continuously applied (FIG. 7A), and when a voltage pulse is applied while increasing the pulse peak value (FIG. 7B). There is. First, the case where the pulse crest value is a constant voltage (FIG. 7A) will be described.

In FIG. 7A, T1 and T2 are the pulse width and pulse interval of the voltage waveform.
0 milliseconds, T2 is 10 microseconds to 100 milliseconds,
The height of the triangular wave (the peak voltage for the energization forming) is properly selected depending on the form of the surface conduction electron-emitting device, an appropriate degree of vacuum, for example, under vacuum atmosphere of about 10 ^-5 Torr, the number of seconds tens Min. Note that the waveform applied between the electrodes of the element is not limited to a triangular wave, and a desired waveform such as a rectangular wave may be used.

T1 and T2 in FIG. 7b are the same as those in FIG. 7a, and the peak value of the triangular wave (peak voltage at the time of energization forming) is increased, for example, in steps of about 0.1 V and applied under an appropriate vacuum atmosphere.

In the energization forming process in this case, the element current is measured at a voltage that does not locally destroy or deform the conductive thin film 4 during the pulse interval T2, for example, a voltage of about 0.1 V, and the resistance is measured. A value is obtained. For example, when a resistance of 1 MΩ or more is indicated, the energization forming is terminated.

4) Next, it is desirable to apply a process called an activation process to the element after the energization forming.

The activation step is, for example, 10 ^-4 to 10 ^-5
Similar to energization forming, a process of repeatedly applying a voltage pulse having a constant pulse peak value at a degree of vacuum of about Torr, and depositing carbon and carbon compounds caused by an organic substance present in a vacuum on a conductive thin film. Element current If,
This is a process for significantly changing the emission current Ie. The activation process ends while measuring the device current If and the emission current Ie, for example, when the emission current Ie is saturated. Further, it is preferable that the voltage pulse to be applied is performed by an operation drive voltage.

Here, the carbon and the carbon compound are graphite (indicating both single and polycrystalline) and amorphous carbon (indicating a mixture of amorphous carbon and polycrystalline graphite). The thickness is preferably Å or less, more preferably 300 Å or less.

5) It is preferable that the electron-emitting device thus produced is operated and driven in an atmosphere having a higher degree of vacuum than the energization forming step and the activation step.
80 ° C. to 150 ° C. in an atmosphere with a higher degree of vacuum
It is desirable to drive operation after heating.

The degree of vacuum higher than the degree of vacuum in the energization forming step and the activation treatment is, for example, a degree of vacuum of about 10 ⁻⁶ or more, more preferably an ultrahigh vacuum system, and a new carbon and carbon compound. Is a vacuum degree that hardly deposits on the conductive thin film. By doing so, the element current If,
The emission current Ie can be stabilized.

FIG. 8 is a schematic configuration diagram of a measurement evaluation apparatus for measuring the electron emission characteristics of the device having the configuration shown in FIG. 8, the same reference numerals as those in FIG. 4 denote the same components. Reference numeral 81 denotes a device voltage Vf applied to the electron-emitting device.
, A current meter 80 for measuring a device current If flowing through the conductive thin film 4 between the device electrodes 2 and 3, and an emission current 84 emitted from an electron emission portion of the device.
e, an anode electrode 83 for capturing a voltage, a high-voltage power supply 83 for applying a voltage to the anode electrode 84, an ammeter 82 for measuring an emission current Ie emitted from the electron-emitting portion 5 of the device, and a vacuum 85. The device, 86 is an exhaust pump.

Next, the image forming apparatus of the present invention will be described.

The electron source substrate used in the image forming apparatus is formed by arranging a plurality of surface conduction electron-emitting devices on the substrate.

In a method of arranging the surface conduction electron-emitting devices, the surface conduction electron-emitting devices are arranged in parallel, and both ends of each element are connected by wiring in a ladder-type arrangement (hereinafter referred to as a ladder-type arrangement electron source substrate). And a simple matrix arrangement in which an X-directional wiring and a Y-directional wiring are connected to a pair of device electrodes of a surface conduction electron-emitting device, respectively (hereinafter referred to as a matrix-type disposed electron source substrate). Note that an image forming apparatus having a ladder-type arranged electron source substrate requires a control electrode (grid electrode) that is an electrode for controlling the flight of electrons from the electron-emitting devices.

The configuration of the electron source based on this principle will be described below with reference to FIG. Reference numeral 91 denotes an electron source substrate, 92 denotes an X-direction wiring, 93 denotes a Y-direction wiring, 94 denotes a surface conduction electron-emitting device, and 95 denotes a connection. The surface conduction electron-emitting device 94 may be either the above-mentioned flat type or the vertical type.

In the figure, the substrate used as the electron source substrate 91 is the above-mentioned glass substrate or the like, and the shape is appropriately set according to the application.

The m X-directional wirings 92 are Dx, Dx2,
.., Dxm, and the Y direction wiring 93 is Dy1, D
.., Dyn. Further, the material, the film thickness, and the wiring width are appropriately set so that a substantially uniform voltage is supplied to many surface conduction type elements. A matrix wiring is formed by electrically separating the m X-directional wirings 92 and the n Y-directional wirings 93 by an interlayer insulating layer (not shown). (M and n are both positive integers).

The interlayer insulating layer (not shown) is formed in a desired region on the entire surface or a part of the substrate 91 on which the X-directional wiring 92 is formed. The X-direction wiring 92 and the Y-direction wiring 93 are respectively drawn as external terminals.

Further, the device electrodes (not shown) of the surface conduction electron-emitting device 94 are electrically connected to the m X-directional wirings 92, the n Y-directional wirings 93 and the connection 95.

The surface conduction electron-emitting device may be formed on either the substrate or the interlayer insulating layer (not shown).

As will be described later in detail, the X-direction wiring 9
2 is electrically connected to a scanning signal generating means (not shown) for applying a scanning signal for scanning a row of the surface conduction electron-emitting devices 94 arranged in the X direction according to an input signal. On the other hand, the Y-direction wiring 93 includes a modulation signal generating means (not shown) for applying a modulation signal for modulating each of the rows of the surface conduction electron-emitting elements 94 arranged in the Y-direction in accordance with an input signal. It is electrically connected. Further, the driving 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.

In the above configuration, individual elements can be selected and driven independently only by simple matrix wiring. Next, an image forming apparatus using the matrix-type arranged electron source substrate prepared as described above will be described with reference to FIGS. 10, 11, and 12. FIG. FIG. 10 is a basic configuration diagram of an image forming apparatus, FIG. 11 is a block diagram of a fluorescent film, and FIG. 12 is a block diagram of a driving circuit for displaying in accordance with an NTSC television signal. Represents a device. In FIG. 10, reference numeral 91 denotes a power supply substrate on which an electron-emitting device is formed, 101 denotes a rear plate on which the electron source substrate 91 is fixed, and 106 denotes a fluorescent film 1 on the inner surface of a glass substrate 103.
04 is a face plate on which a metal back 105 and the like are formed, 102 is a support frame, 101 is a rear plate,
The envelope 108 is constituted by these members.

In FIG. 10, reference numeral 94 corresponds to the electron-emitting portion in FIG. Reference numerals 92 and 93 denote X-direction wiring and Y-direction wiring connected to a pair of device electrodes of the surface conduction electron-emitting device.

The envelope 108 is composed of the face plate 106, the support frame 102, and the rear plate 101 as described above. The rear plate 101 is mainly used for reinforcing the strength of the electron source substrate 91. When the electron source substrate 91 itself has sufficient strength, the separate rear plate 101 is unnecessary, and the support frame 102 is directly provided on the electron source substrate 91, and the face plate 106 and the support frame 1 are provided.
02, the envelope 108 may be constituted by the electron source substrate 91. In FIG. 11, reference numeral 112 denotes a phosphor. The phosphor 112 is composed of only the phosphor in the case of monochrome, but in the case of a color phosphor film, depending on the arrangement of the phosphor, a black conductive material 111 called a black stripe or a black matrix is used.
And a phosphor 112. Black stripe,
The purpose of providing the black matrix is to make the color separation between the phosphors 112 of the necessary three primary color phosphors black in the case of color display, thereby making color mixing less noticeable, and contrast due to external light reflection on the phosphor film 104. Is to suppress the decrease in The material of the black stripe is not limited to a commonly used material containing graphite as a main component, as long as it is conductive and has little light transmission and reflection.

As a method of applying the phosphor on the glass substrate 103, a precipitation method or a printing method is used regardless of monochrome or color. A metal back 105 (FIG. 10) is provided on the inner surface side of the fluorescent film 104 (FIG. 10). The purpose of the metal back is to improve the brightness by mirror-reflecting the light emitted from the phosphor toward the inner surface side to the face plate 106 side, to act as an electrode for applying an electron beam acceleration voltage, This is to protect the phosphor from damage caused by the impact of negative ions generated in the chamber. After forming the fluorescent film, the metal back is subjected to a smoothing treatment (usually called filming) of the inner surface of the fluorescent film, and then to the Al backing.
Can be produced by depositing by vacuum evaporation or the like.

The face plate 106 may be provided with a transparent electrode (not shown) on the outer surface side of the fluorescent film 104 in order to further increase the conductivity of the fluorescent film 104.

The envelope 108 passes through an exhaust pipe (not shown),
The degree of vacuum is set to about 0 ^-7 Torr, and sealing is performed. In some cases, getter processing is performed to maintain the degree of vacuum of the envelope 108 after sealing. This is done by heating a getter disposed at a predetermined position (not shown) in the envelope 108 by a heating method such as resistance heating or high-frequency heating immediately before or after sealing the envelope 108, and performing vapor deposition. This is a process for forming a film. The getter is usually composed mainly of Ba or the like,
Due to the adsorption action of the deposited film, for example, 1 × 10 ⁻⁵ Torr
Alternatively, a degree of vacuum of 1 × 10 ⁻⁷ Torr is maintained. Steps after forming the surface conduction electron-emitting device are appropriately set.

Next, a schematic configuration of a driving circuit for performing a television display based on an NTSC television signal in an image forming apparatus constituted by using a matrix type arrangement electron source substrate will be described with reference to a block diagram of FIG. explain. 121 is the display panel, 122 is a scanning circuit, 123
Is a control circuit, 124 is a shift register, 125 is a line memory, 126 is a synchronization signal separation circuit, 127 is a modulation signal generator, and Vx and Va are DC voltage sources.

The function of each part will be described below. First, the display panel 121 is connected to the terminals Dox1 to Doxm and the terminal Doy.
It is connected to an external electric circuit via 1 to Doyn and the high voltage terminal Hv. Terminals Dox1 to Doxm
Scanning 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.

On the other hand, to the terminals Dy1 to Dyn, a modulation signal for controlling an output electron beam of each element of the one row of surface conduction electron-emitting devices selected by the scanning signal is applied. In addition, a DC voltage source Va is applied to the high voltage terminal Hv.
For example, a DC voltage of 10 [kV] is supplied, which is an accelerating voltage for applying sufficient energy to the electron beam output from the surface conduction electron-emitting device to excite the phosphor.

Next, the scanning circuit 122 will be described. This circuit includes M switching elements inside (in the figure, schematically indicated by S1 to Sm), and each switching element is provided with an output voltage of a DC voltage source Vx or 0 V.
[V] (ground level) is selected and electrically connected to the terminals Dx1 to Dxm of the display panel 121. Each of the switching elements S1 to Sm operates based on the control signal Tscan output from the control circuit 123, but can be actually configured by combining switching elements such as FETs.

The DC voltage source Vx is controlled based on the characteristics (electron emission threshold voltage) of the surface conduction electron-emitting device so that the drive voltage applied to the unscanned device is equal to or lower than the electron emission threshold voltage. It is set to output voltage.

The control circuit 123 has a function of matching the operations of the respective units so that appropriate display is performed based on an image signal input from the outside. A synchronization signal Tsync sent from a synchronization signal separation circuit 126 described below.
Tscan, Tsft and Tm for each part based on
ry control signals are generated.

The synchronizing signal separating circuit 126 is a circuit for separating a synchronizing signal component and a luminance signal component from an NTSC television signal input from the outside, and can be formed by using a frequency separating (filter) circuit. As is well known, the synchronization signal separated by the synchronization signal separation circuit 126 includes a vertical synchronization signal and a horizontal synchronization signal, but is illustrated here as a Tsync signal for convenience of explanation. On the other hand, the luminance signal component of the image separated from the television signal is referred to as a DATA signal for the sake of convenience, and the signal is input to the shift register 124.

The shift register 124 is for serially / parallel converting the DATA signal input serially in time series for each line of an image, and operates based on a control signal Tsft sent from the control circuit 123. . (That is, the control signal Tsft is
24 shift clocks. )
The data for one line of the serial / parallel-converted image (corresponding to the drive data for N electron-emitting devices) is I
It is output from the shift register 124 as N parallel signals of d1 to Idn.

The line memory 125 is a storage device for storing data for one line of an image for a required time only, and stores the contents of Idl to Idn as appropriate according to a control signal Tmry sent from the control circuit 123. The stored contents are output as Id1 to Idn and input to the modulation signal generator 127.

The modulation signal generator 127 outputs the image data I
A signal source for appropriately driving and modulating each of the surface conduction electron-emitting devices in accordance with each of d1 to Idn, and an output signal thereof is supplied to the display panel 1 through terminals Doy1 to Doyn.
21 is applied to the surface conduction electron-emitting device.

The electron-emitting device according to the present invention has an emission current Ie
Has the following basic characteristics. That is, electron emission has a clear threshold voltage Vth, and electron emission occurs only when a voltage equal to or higher than Vth is applied.

For a voltage equal to or higher than the electron emission threshold, the emission current also changes in accordance with the change in the voltage applied to the device. Note that the value of the electron emission threshold voltage Vth and the degree of change of the emission current with respect to the applied voltage may be changed by changing the material, configuration, and manufacturing method of the electron emission element,
In any case, the following can be said.

That is, when a pulse-like voltage is applied to the device, for example, when a voltage lower than the electron emission threshold is applied, no electron emission occurs, but when a voltage higher than the electron emission threshold is applied, the electron beam is output. Is done. At that time, first, the intensity of the output electron beam can be suppressed by changing the peak value Vm of the pulse. Second, it is possible to control the total amount of charges of the output electron beam by changing the pulse width Pw.

Therefore, as a method of modulating the electron-emitting device in accordance with the input signal, a voltage modulation method, a pulse width modulation method, or the like can be used. A voltage modulation circuit that generates a voltage pulse and modulates the peak value of the pulse appropriately according to input data is used.

In order to implement the pulse width modulation method, the modulation signal generator 127 generates a voltage pulse having a constant peak value, but modulates the width of the voltage pulse appropriately according to input data. A circuit of a width modulation system is used.

With the series of operations described above, the image forming apparatus of the present invention can display a television using the display panel 121. Although not specifically described in the above description, the shift register 124 and the line memory 125 may be of a digital signal type or an analog signal type. In short, serial / parallel conversion and storage of image signals can be performed at a predetermined speed. It should be done.

When the digital signal type is used, it is necessary to convert the output signal DATA of the synchronizing signal separating circuit 126 into a digital signal. This can be achieved by providing an A / D converter at the output portion of the 126. In connection with this, the circuit used for the modulation signal generator 127 is slightly different depending on whether the output signal of the line memory 125 is a digital signal or an analog signal.

First, the case of a digital signal will be described.
In the voltage modulation method, for example, a well-known D / A conversion circuit may be used as the modulation signal generator 127, and an amplification circuit or the like may be added as necessary. In the case of the pulse width modulation system, the modulation signal generator 127 includes, for example, a high-speed oscillator, a counter for counting the number of waves output from the oscillator, and a comparator for comparing the output value of the counter with the output value of the memory. (Comparator) can be used. If necessary, an amplifier for amplifying the voltage of the pulse width modulated signal output from the comparator to the drive voltage of the surface conduction electron-emitting device may be added.

Next, the case of an analog signal will be described.
In the voltage modulation method, for example, an amplification circuit using a well-known operational amplifier or the like may be used as the modulation signal generator 127, and a level shift circuit or the like may be added as necessary. In the case of the pulse width modulation method, for example, a well-known voltage-controlled oscillation circuit (VCO) may be used, and an amplifier for amplifying the voltage up to the driving voltage of the surface conduction electron-emitting device may be added as necessary. You may.

In the image forming apparatus completed as described above, the external terminals Dox1 to Dox are connected to each electron-emitting device.
Electrons are emitted by applying a voltage through xm, Doy1 to Doyn, and a high voltage is applied to a metal back 105 or a transparent electrode (not shown) through a high voltage terminal Hv to accelerate an electron beam and cause the fluorescent film 104 to emit light. Collide,
An image can be displayed by exciting and emitting light.

The configuration described above is a schematic configuration necessary for manufacturing a suitable image forming apparatus used for display and the like. For example, detailed portions such as materials of each member are not limited to the above-described contents. Is appropriately selected so as to be suitable for the use of the image forming apparatus. Also, the NTSC system has been described as an example of the input signal, but the present invention is not limited to this, and PAL, SECA
Various systems such as the M system may be used, and a TV signal composed of a larger number of scanning lines (for example, a high-definition TV including the MUSE system) may be used.

Next, the above-mentioned ladder-type arrangement electron source substrate and an image forming apparatus using the same will be described with reference to FIGS.

In FIG. 13, reference numeral 130 denotes an electron source substrate, 1
31 is an electron-emitting device, 132 is a common wiring connected to the electron-emitting devices Dx1 to Dx10. A plurality of the electron-emitting devices 131 are arranged on the substrate 130 in parallel in the X direction (this is called an element row). A plurality of such element rows are arranged on a substrate to form a ladder-type electron source substrate. By appropriately applying a drive voltage between the common wires of each element row, each element row can be driven independently. That is, a voltage equal to or higher than the electron emission threshold may be applied to an element row that emits an electron beam, and a voltage equal to or lower than the electron emission threshold may be applied to an element row that does not emit an electron beam. Further, the common wirings Dx2 to Dx9 between the element rows, for example, Dx2 and Dx3 may be the same wiring.

FIG. 14 is a view showing the structure of an image forming apparatus having a ladder-type electron source. 140 is a grid electrode, 141 is a hole through which electrons pass, 142
Is a terminal outside the container made of Dox1, Dox2,..., Doxm, and 143 is a G connected to the grid electrode 140.
, Gn, the external terminal 130 is an electron source substrate in which the common wiring between the element rows is the same as described above. 10 and 13 indicate the same members. The difference from the above-described image forming apparatus having the simple matrix arrangement (FIG. 10) is that a grid electrode is provided between the electron source substrate 130 and the face plate 106.

A grid electrode 140 is provided between the substrate 130 and the face plate 106. The grid electrode 140 is capable of modulating the electron beam emitted from the surface conduction electron-emitting device, and allows the electron beam to pass through a stripe-shaped electrode provided orthogonally to the ladder-type arrangement element row. One circular hole 141 is provided for each element. The shape and installation position of the grid need not always be as shown in FIG. 14, and a large number of passage openings may be provided in a mesh shape as openings, and may be provided, for example, around or near the surface conduction electron-emitting device. .

The outer container terminal 142 and the outer grid container terminal 143 are electrically connected to a control circuit (not shown).

In this image forming apparatus, a modulation signal for one line of an image is simultaneously applied to the grid electrode rows in synchronization with the sequential driving (scanning) of the element rows one by one.
By controlling the irradiation of each electron beam to the phosphor, an image can be displayed line by line.

Further, according to the present invention, it is possible to provide an image forming apparatus suitable for a display device such as a television conference system and a computer as well as a display device for a television broadcast. Further, it can be used as an image forming apparatus as an optical printer including a photosensitive drum or the like.

The electron-emitting device is applicable not only to a surface conduction electron-emitting device but also to a cold cathode electron source such as a MIM electron-emitting device and a field emission electron-emitting device.
Further, the present invention can be applied to an image forming apparatus using a thermoelectron source.

[0092]

The present invention will be described in detail with reference to the following examples. Example 1 An image forming apparatus was manufactured using a matrix-type arranged electron source substrate 91 (FIG. 9) having the surface conduction electron-emitting devices obtained as described above.

FIG. 1 is a sectional view showing the structure of the image forming apparatus manufactured in the embodiment. In the figure, 6 is a face plate on which an image forming member (not shown) is mounted, and 12 is a support frame. The electron source substrate 91, the face plate 6, and the support frame 12 are obtained by cutting blue sheet glass.
Each member was sealed with frit glass 7 and fixed.

In FIG. 1, reference numeral 8b denotes an aluminum heat conducting member for uniformizing the temperature on the electron source substrate 91, and 8a denotes an aluminum heat conducting member for conducting heat to the face plate 6 and the support frame 12. Silicon grease (not shown) is applied as a heat conductive paste to each contact portion between the heat conductive members 8a and 8b and the display panel including the electron source substrate 91, the face plate 6 and the support frame 12, and the gap portion is formed. The thermal resistance was reduced by interposing silicon grease in the steel. The thermal resistance is further reduced by improving the flatness of the display panel and the heat conducting member by polishing or the like.

The size of the heat conducting member 8b is 300 × 350 m
m, the thickness was 3 mm, the peripheral portion had a thickness of 5 mm at the upper end, and the middle portion had a thickness of 2 mm. The thickness of the heat conducting member 8a was 17 mm.

The following describes the face plate 6 and the support frame 1
2, and a method of manufacturing a display panel including the power supply substrate 91 will be briefly described. Details are shown in the embodiment. First,
The frit glass 7 was previously applied to the face plate 6 on which the image forming member was mounted by a dispenser according to the above-described method, and the support frame 12 was adjusted to a desired position, and then temporarily fired and fired to be fixed. Next, the electron source substrate 9
Frit glass 7 was applied to 1 with a dispenser, and the support frame 12 and the face plate 6 prepared above were preliminarily baked, baked and fixed after performing predetermined alignment.

After completion of the assembling process, the inside of the envelope produced in the above process was evacuated to about 10 ^-6 Torr through an exhaust pipe (not shown) in order to evacuate the inside. Thereafter, the exhaust pipe was sealed. Silicon grease was applied on the electron source substrate, the support frame, and the face plate of the display panel in contact with the heat conductive member, and then the heat conductive member was provided. In order to absorb the difference in the amount of thermal expansion between the material of the display panel and the aluminum plate and to avoid breakage, on the opposite surface of the support frame, one of the heat conducting members is a pressing surface, and the other is a pressing surface by a spring. (Not shown). Finally, terminals (not shown) were connected to corresponding external drive circuits (not shown). The image forming apparatus thus obtained was driven by sending an electric signal from an external drive circuit to display an image. As a result, no color shift was observed in the image even when the image was displayed for a long time, and no damage occurred. Also, when the thermal stress in the display panel was calculated by computer simulation,
It became clear that the thermal stress was reduced by about 27% by installing the heat conducting member.

As described above, the temperature difference between the members is reduced by the provision of the heat conductive member, the deterioration of the image quality such as color shift can be prevented, and the strength of the display panel can be improved. Example 2 An image forming apparatus was manufactured using the matrix-type arranged electron source substrate 91 (FIG. 9) having the surface conduction electron-emitting devices obtained as described above. FIG. 2 is a cross-sectional view illustrating a configuration of the image forming apparatus manufactured in the example. FIG.
1, the same reference numerals as those in FIG. 1 denote the same components.

In the figure, 6 is a face plate on which an image forming member (not shown) is mounted, and 12 is a support frame. The electron source substrate 91, the face plate 6, and the support frame 12 are obtained by cutting blue plate glass, and the respective members are sealed with frit glass 7 and fixed.

In FIG. 2, reference numeral 8b denotes an aluminum heat conducting member for uniformizing the temperature on the electron source substrate 91, and 8a denotes an aluminum heat conducting member for conducting heat to the face plate 6 and the support frame 12. is there. Silicon grease (not shown) is applied as a heat conductive paste to a contact portion between the heat conductive members 8a and 8b and the display panel including the electron source substrate 91, the face plate 6, and the support frame 12, and a heat resistance due to the gap is provided. Was reduced. The thermal resistance is further reduced by improving the flatness of the display panel and the heat conducting member by polishing or the like.

Reference numeral 9 denotes a radiator provided with fins formed by cutting an aluminum plate, and the radiator can reduce the temperature of the entire image forming apparatus. The longitudinal direction of the fin was formed so as to coincide with the vertical direction of the display panel. The heat radiator may be formed integrally with the heat conducting member, and there is no problem even if the heat radiator is extended along the support frame.

The size of the fin was 10 cm × 2 cm and the thickness was 2 mm, and the distance between the fins was 4 mm.

The method of manufacturing a display panel including the face plate 6, the support frame 12, and the electron source substrate 91 is the same as that in the first embodiment. In this example, after the display panel was completed, silicon grease was applied to the heat radiator 9 and fixed to the heat conducting member 8b with screws (not shown). The image forming apparatus thus obtained was driven by sending an electric signal from an external drive circuit to display an image. As a result, no color shift was observed in the image even when the image was displayed for a long time, and no damage occurred. Further, although the temperature differs depending on the location of the display panel, the temperature was lowered by about several degrees Celsius as compared with Example 1.

As described above, the temperature difference between the members was reduced by the installation of the heat conducting member and the heat radiator, and the deterioration of the image quality such as color shift could be prevented.

[0105]

Embodiment 3 An image forming apparatus was manufactured using a matrix-type arranged electron source substrate 91 (FIG. 9) having the surface conduction electron-emitting devices obtained as described above.

FIG. 3 is a sectional view showing the structure of the image forming apparatus manufactured in the embodiment. In FIG. 3, the same reference numerals as those in FIG. 2 indicate the same components. In the drawing, reference numeral 6 denotes a face plate on which an image forming member (not shown) is mounted. Reference numeral 12 denotes a support frame. The electron source substrate 91, the face plate 6, and the support frame 12 are formed by cutting blue plate glass. Yes,
Each member was sealed with frit glass 7 and fixed.

In FIG. 3, reference numeral 8b denotes an aluminum heat conductive member for achieving temperature uniformity on the electron source substrate 91, and 8a denotes an aluminum heat conductive member for transmitting heat to the face plate 6 and the support frame 12. is there. Silicon grease (not shown) is applied as a heat conductive paste to a contact portion between the heat conductive members 8a and 8b and the display panel including the electron source substrate 91, the face plate 6, and the support frame 12, and a heat resistance due to the gap is provided. Was reduced. The thermal resistance is further reduced by improving the flatness of the display panel and the heat conducting member by polishing or the like.

Reference numeral 9 denotes a radiator provided with fins formed by cutting an aluminum plate, and this radiator can reduce the temperature of the entire image forming apparatus. The longitudinal direction of the fin was formed so as to coincide with the vertical direction of the display panel. The heat radiator may be formed integrally with the heat conducting member, and there is no problem even if the heat radiator is extended along the support frame. A fan 20 for forcibly cooling the radiator 9 has a performance of an air flow rate of 1 m ³ / min.

The method of manufacturing a display panel including the face plate 6, the support frame 12, and the electron source substrate 91 is the same as that of the second embodiment.

The image forming apparatus thus obtained was driven by sending an electric signal from an external drive circuit (not shown) to display an image. As a result, no color shift was observed in the image even when the image was displayed for a long time, and no damage occurred. Further, although the temperature differs depending on the location of the display panel, the temperature was lowered by about several degrees Celsius as compared with Example 1.

As described above, in addition to the heat conducting member,
Even if the radiator and the forced cooling fan were installed together, the temperature difference between the members was reduced, and deterioration of the image quality such as color shift could be prevented.

[0112]

As described above, according to the present invention, a heat conductive member having a thermal conductivity at least higher than that of the electron source substrate, the support frame, and the face plate is provided on the electron source substrate, the support frame, and the face plate. Accordingly, it is possible to reduce the temperature difference between the members, not only to improve the strength by reducing the thermal stress, but also to prevent the image quality from deteriorating due to color misregistration. In addition, a combination of a heat conducting member, a radiator, and forced air cooling is also possible, and these are effective.

As a result, the safety of the image forming apparatus is increased, and a high-quality display panel can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an image forming apparatus showing one embodiment of the present invention.

FIG. 2 is a sectional view showing one embodiment of the present invention.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIGS. 4A and 4B are a schematic plan view and a cross-sectional view, respectively, showing the configuration of a basic surface conduction electron-emitting device used in the present invention.

FIG. 5 is a schematic view showing a configuration of a basic vertical surface conduction electron-emitting device used in the present invention.

FIG. 6 is a process chart showing an example of a method for manufacturing a surface conduction electron-emitting device used in the present invention.

FIGS. 7A and 7B are graphs showing voltage waveform examples of different energization forming, respectively.

FIG. 8 is a schematic configuration diagram illustrating an example of a measurement evaluation device for measuring electron emission characteristics.

FIG. 9 is an explanatory diagram showing a configuration of an electron source having a simple matrix arrangement.

FIG. 10 is a schematic configuration perspective view of an image forming apparatus.

FIGS. 11A and 11B are explanatory diagrams showing configurations of two types of fluorescent films of FIGS.

FIG. 12 is a block diagram of an image forming apparatus having a drive circuit for performing display in accordance with an NTSC television signal.

FIG. 13 is an explanatory diagram showing a configuration of an electron source having a ladder arrangement.

FIG. 14 is a schematic configuration perspective view of an image forming apparatus in which an electron source having a ladder arrangement is incorporated.

FIG. 15 is a plan view showing a configuration of a conventional surface conduction electron-emitting device.

FIG. 16 is an explanatory view showing a heat radiation method of a conventional image forming apparatus.

FIG. 17 is a cross-sectional view showing an example of a basic flat plate type image forming apparatus using a conventional surface conduction electron-emitting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2, 3 Element electrode 4 Conductive thin film 5 Electron emission part 6 Face plate 7 Frit glass 8a, 8b Heat conduction member 9 Heat radiator 12 Support frame 20 Fan 51 Step formation part 80 Ammeter 81 Power supply 82 Ammeter 83 High voltage power supply 84 Anode electrode 85 Vacuum device 86 Exhaust pump 91 Electron source substrate 92 X-direction wiring 93 Y-direction wiring 94 Surface conduction electron-emitting device 95 Connection 101 Rear plate 102 Support frame 103 Glass substrate 104 Fluorescent film 105 Metal back 106 Face plate 107 High voltage Terminal 108 Enclosure 111 Black conductive material 112 Phosphor 121 Display panel 122 Scanning circuit 123 Control circuit 124 Shift register 125 Line memory 126 Synchronous signal separation circuit 127 Modulation signal generator 130 Electron source substrate 131 Electron emitting element 1 2 common wiring 140 grid electrodes 141 holes 142 vessel terminals 143 vessel terminals Vx, Va dc voltage sources

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-261026 (JP, A) JP-A-4-137331 (JP, A) JP-A-4-132139 (JP, A) JP-A-2- 92653 (JP, A) JP-A-4-68361 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 29/86 H01J 31/12 H01J 31/15

Claims (7)

(57) [Claims] 1. An image forming apparatus, comprising: an electron source substrate on which an electron emitting element group is mounted; and an image forming apparatus arranged to face the electron source substrate and forming an image by irradiation of an electron beam emitted from the electron emitting element group. A face plate on which members are mounted,
In an image forming apparatus having at least a display panel including a support frame disposed between a peripheral portion of the electron source substrate and the face plate, a thermal conductivity is higher than that of the electron source substrate, the support frame, and the face plate. Heat conduction member on the outer surface of the electron source substrate,
An image forming apparatus, which is disposed along an outer surface of a support frame and an outer surface of a face plate excluding a display unit. 2. The image forming apparatus according to claim 1, further comprising a heat radiator attached to or integrally formed with the heat conductive member. 3. The image forming apparatus according to claim 2, wherein the radiator is provided with the fin such that the longitudinal direction of the fin coincides with the longitudinal direction of the image forming apparatus. 4. The image forming apparatus according to claim 1, wherein the heat radiation means of the heat radiation body uses natural convection heat transfer. 5. The image forming apparatus according to claim 1, wherein the heat radiation means of the heat radiation body uses forced convection heat transfer. 6. The image forming apparatus according to claim 1, wherein a heat conductive paste is interposed in a gap between the heat source and the electron source substrate, the face plate, and the support frame. . 7. The image forming apparatus according to claim 1, wherein the electron-emitting device group is a surface conduction electron-emitting device.