Electric lamp or space discharge component or device manufacturi – Process – With assembly or disassembly
Reexamination Certificate
2000-11-03
2003-08-12
Ramsey, Kenneth J. (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
With assembly or disassembly
C427S532000, C427S537000, C427S064000, C313S495000, C313S496000
Reexamination Certificate
active
06604972
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to suitable manufacturing method for an image-forming apparatus using an electron beam such as a field emission display (FED) or cathode ray tube (CRT), for example, and a face plate used in such an image-forming apparatus.
2. Related Background Art
There is a demand for much larger image-forming apparatuses such as CRTs, and a great deal of research is being carried out in this regard. As size increases, achieving thinness, light weight, and low cost of the apparatus have become major concerns.
However, as the structure of a CRT is such that electrons accelerated by a high voltage are deflected by deflecting electrodes, and irradiate a phosphor on the face plate, causing excitation, when the size is increased, depth is necessary in principle, making it difficult to achieve thinness and light weight.
The inventor has been conducting research into an image-forming apparatus using surface conduction electron-emitting devices, as an image-forming apparatus capable of solving the above described problem.
Application to a multi-electron-beam source of an electron-emitting device by means of an electrical wiring method such as that shown in
FIG. 4
are disclosed in U.S. Pat. No. 5,936,342, U.S. Pat. No. 5,451,835, and WO 00/44022, etc.
The apparatus shown in
FIG. 4
has a 2-dimensional arrangement of a plurality of surface conduction electron-emitting devices, and, as shown in the figure, these devices constitute a multi-electron-beam source wired in simple matrix form.
FIG. 4
shows a circuit diagram for the case where surface conduction elctron-emitting devices are connected by matrix-wiring.
In the figure, reference numeral
4012
schematically indicates a surface conduction elctron-emitting device, reference numeral
4002
indicates column-directional wiring, reference numeral
4003
indicates row-directional wiring, and reference numeral
4004
indicates resistances.
For the purposes of illustration, a 6×6 matrix is shown, but the scale of the matrix is not, of course, limited to this: as many devices as are sufficient to perform the desired image display are arrayed and wired.
FIG. 5
shows the structure of a flat type cathode ray tube using this multi-electron-beam source.
In
FIG. 5
, surface conduction electron-emitting devices
4012
are provided on a substrate
4001
, and the structure consists of a rear plate
4005
and side wall
4007
, a face plate
4006
provided with a phosphor layer
4008
, and an electroconductive film (so-called metal back)
4009
on the phosphor layer.
The configuration is such that a high voltage is applied to the metal back
4009
from a high voltage power supply
4010
through a high voltage input terminal
4011
.
In order to output the desired electron beams, in the multi-electron-beam source in which surface conduction electron-emitting devices
4012
are simple-matrix-wired, appropriate electrical signals are applied to the column-directional wiring
4002
and row-directional wiring
4003
.
For example, to drive an arbitrary row of surface conduction electron-emitting devices within the matrix, a selection voltage Vs is applied to the row-directional wiring
4003
of the selected row, and at the same time a non-selection voltage Vns is applied to the row-directional wiring
4003
of the non-selected rows.
In synchronization with this, a drive voltage Ve for outputting electron beams is applied to the column-directional wiring
4002
.
According to this method, voltage Ve−Vs is applied to the surface conduction electron-emitting devices of the selected row, and voltage Ve−Vns is applied to the surface conduction electron-emitting devices of the non-selected rows.
If the size of these voltages Ve, Vs, and Vns is adjusted appropriately, an electron beam of the desired intensity is output only from the surface conduction electron-emitting devices of the selected row, and if a different drive voltage Ve is applied to each column-directional wire, electron beams of different intensity are output from each device of the selected row.
As the response speed of the surface conduction electron-emitting devices is fast, by changing the length of time for which the drive voltage Ve is applied, it is also possible to change the length of time for which the electron beam is output.
By means of the above described voltage application, the electron beams output from the multi-electron-beam source configured by surface conduction electron-emitting devices are applied to the metal back
4009
to which a high voltage Va is being applied, pass through the metal back
4009
, strike the phosphor of the phosphor layer
4008
, which is a target, and excite the phosphor, causing it to emit light.
Therefore, the image-forming apparatus shown in
FIG. 5
becomes an image display apparatus by appropriately applying voltage signals corresponding to image information, for example.
Thus, the above described image display apparatus displays an image by applying a high voltage to the metal back
4009
, generating an electric field and accelerating electrons between the rear plate
4005
and the face plate
4006
, and exciting the phosphor, causing it to emit light.
Meanwhile, in order to realize a drastically thinner image display apparatus, it is necessary to reduce the distance between the rear plate
4005
and face plate
4006
shown in
FIG. 5
, for example.
Therefore, a considerably higher field strength arises between the rear plate
4005
and face plate
4006
than in the case of a CRT. Also, the higher the acceleration voltage, the stronger is the light emission and the greater the brightness of the image display apparatus.
The metal back
4009
is generally configured by a metal film. The reasons for this are to enable a high voltage to be applied to the entire phosphor layer, to remove charge by the metal back from the phosphor which is an insulator, and also to enable light emitted from the phosphor toward the rear (in the direction of the rear plate) to be conveyed (reflected) toward the front by means of a mirror-surface effect. It is therefore necessary for the metal back to be a continuous film with a certain degree of thickness.
As the accelerated electron beams must excite the phosphor through the metal back
4009
, the thickness of the metal back
4009
is limited, although this also depends on the potential applied to the metal back.
Meanwhile, as the phosphor is generally a powder, the phosphor layer
4008
is porous and its surface has a considerable number of irregularities.
There are also a considerable number of irregularities on the surfaces of black members (such as the black matrix) provided for such reasons as preventing color mixing of the phosphor, preventing color shifting even if the beam position shifts a certain amount, and improving the image contrast by absorbing external light.
So, it is difficult to produce a continuous metal film directly on the phosphor layer with desired thickness, and so a filming step is generally used as the metal back creation step.
In this filming step, an acrylic or similar resin film is disposed on the surface of the phosphor layer, etc., and the surface of the phosphor layer, etc., is made flat. On the flattened film (resin film), a metal film is formed by means of vacuum evaporation, etc., and then the resin film is thermally decomposed and eliminated by baking, as a result of which the metal film is attached to the phosphor layer, creating the metal back.
As the above described resin film undergoes thermal decomposition and elimination by baking after the metal film is disposed, the resin film becomes a gas, and holes through which that gas escapes are created in the metal back (metal film) (see FIG.
13
). In
FIG. 13
, reference numeral
4006
denotes the face plate, reference numeral
2
denotes phosphor particles, reference numeral
3
denotes the metal film (metal back), and reference numeral
104
denotes protrusions formed around the holes created in the metal film (metal back). In many cases, the
Colón German
Ramsey Kenneth J.
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