JPH03250543A - Display device - Google Patents

Abstract

PURPOSE:To provide a display device with as high a brightness and contrast as CRT and as high a flatness as liquid crystal display by constituting each unitary light emitting element from an electron emitter, control electrode, collector electrode, and light emitting substance film, which are formed on the surface of a base board. CONSTITUTION:In each of the unitary light emitting elements arranged on a display in matrix form, an electron emitter 12, control electrode 14, and electron shield 17 have negative potential while electron collector electrodes 15 have pos. potentials suitable for R, G, B light-emitting materials. Electrons emitted by the emitter 12 are deflected under quantitative control by the control electrode 14, and bombard a certain electrode 15 with an energy corresponding to the potential difference so as to excite a light emitting substance film 16 to cause emission of a specific color light, and are released out through a clear sealant 18. The light emission mechanism is quite the same as that of CRT display, having high brightness and contrast performance, and can be accomplished as flat as a liquid crystal display as one electron source corresponds to each picture element.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] [Industrial Application Field] The present invention relates to display devices used in televisions, computers, etc., and particularly relates to flattened display devices.

(Conventional technology) With the advancement of the information society, display devices are
It has now become indispensable as a machine interface. As the application of display devices to various uses progresses, requirements for display quality and performance have become stricter and more sophisticated. As the current direction of development,
Development of flat panel displays is active, with improvements in performance such as larger size and higher definition, and flattening of devices.

Various technologies and methods have been tried in the development of flat panel displays, such as liquid crystal displays (
LCD), plasma display (FDP), EL display, fluorescent display tube (VFD), etc., each of which has its advantages and disadvantages, has been put into practical use. Among these, LCDs using active matrix are seen as promising not only as displays for man-machine interfaces but also as screens for home televisions. However, LCDs have CRs in screen brightness and contrast.
There are weaknesses in terms of performance, which is far behind T-Display.

On the other hand, CRT displays have high brightness and contrast performance, but because electron beams generated from a single electron source are scanned in a vacuum, it is difficult to make them into flat panels using existing technologies. As flattening techniques for CRT displays, a beam index method and a channel multiplier method have been reported.

Figure 9 shows a CRT using the channel multiplier method.
Conventional examples of flattening displays are shown (A, G,
Knapp et, al, -Large-areach
annel electron multiplfer
f'or CRTapplication IE
E PROCEEDINGS, Vol, 131°Pt, 1. Feb., 1984), in this example, electrons generated from an electron source 1 mounted parallel to the screen are scanned in the line direction by the first deflection plate 2. A relatively low-energy electron beam 3 is inverted by an electron lens 4 mounted opposite the electron source 1, and multiplied and accelerated within a multiplier plate 5. Then, when these accelerated electrons collide with the phosphor surface 6, the phosphor surface 6 selectively emits light. Note that the orbit of the electron is maintained in a vacuum in the metal box 7,
It is also shielded against electric fields.

The key points of this multiplier system are that the electron beam 7 with relatively low energy is used to increase the deflectable angle, and the electron lens 4 that reverses the beam trajectory is used to increase the distance the electron beam travels necessary for scanning. The multiplier plate 5 is used to accelerate the electrons to the energy necessary to excite the phosphor and emit light. However, with this method, a certain amount of thickness is still required to secure the trajectory of the electron beam necessary for scanning, so it is difficult to flatten the panel to a flat panel, as with other methods.

(Problems to be Solved by the Invention) As described above, the brightness of the screen has traditionally been made possible by flat panels such as liquid crystal displays.

The contrast is nowhere near that of a CRT display, and the brightness is similar to that of a CRT display.

There is a problem in that it is difficult to make a flat panel if the contrast is sufficiently high.

The present invention has been made in consideration of the above circumstances, and its purpose is to provide a flat panel display device that has brightness and contrast comparable to that of a CRT display, and can be made as flat as a liquid crystal display. It's about doing.

[Structure of the Invention (Means for Solving the Problems) The gist of the present invention is to apply a microcold cathode tube in which an emitter and a collector for field emission are arranged in a plane to a light emitting element.

That is, the present invention provides a display device in which a plurality of unit light emitting elements are arranged in a matrix on a substrate. a control electrode provided near the emitter to control the amount of electron beam emitted from the emitter; an electron collector electrode provided at a position farther from the emitter than the control electrode; and an electron collector electrode provided on the collector electrode to control the amount of electron beam emitted from the emitter. It consists of a light-emitting thin film that emits light when excited by a beam, and adjacent unit light-emitting elements are separated by an electronic shield, and the area where the unit light-emitting elements are placed is kept in a vacuum by a transparent sealing body placed facing the substrate surface. It was designed to be maintained.

Further, preferred embodiments of the present invention are as follows. That is, the electron shield is an electrode set to a negative potential, the separation of the electron beam between the plurality of electron collector electrodes is performed by an electrode having the same potential as the electron shield, and the light emission formed on the electron collector electrode is body thin membrane Rl
Configuring either G or B to emit light, setting the individual electron collector electrodes to a potential corresponding to each light emission, and the total area of the electron collector electrodes on which the R, G, and B light emitting thin films are formed. is configured in proportion to the product of the luminous efficiency of each electron beam with each luminous energy and the human visual sensitivity, the electron emission emitter is a field emission mechanism, and at least one of the control electrodes is set at a negative potential. At least one of the control electrodes is set to a different potential from the other control electrodes to deflect the emitted electrons, and the control electrodes are formed in multiple layers with an insulator sandwiched between them. at least one of the electrodes is set at a positive potential, and secondary electrons generated by colliding electrons with the control electrode are used as an electron source; At least a part of the surface of the sealing body facing the substrate has conductivity, and that part is set to a positive potential. The conductive part of the sealing body is located near the conductive part of the sealing body facing the electron emission emitter and has a convex shape.

(Operation) According to the present invention having the above configuration, C
While maintaining brightness and contrast comparable to RT, it is possible to achieve flatness comparable to that of a liquid crystal display.

First, brightness and contrast will be explained.

Since the light emitting mechanism is exactly the same as a CRT display, the brightness and contrast performance is high. Furthermore, C
While the RT display extracts light through the light-emitting film, the present invention extracts light from the light-emitting surface side, resulting in higher luminance efficiency. Since the electron-emitting emitter can be formed to a size of several micrometers or less by, for example, silicon micromanipulation technology, there is no problem that the light-emitting surface becomes smaller due to the electron-emitting emitter.

Next, flattening will be explained. The reason why a CRT display needs to be thicker as it has a larger screen is that it must have a larger solid angle to deflect a high-energy electron beam guided from one electron source without distortion. In contrast, in the present invention, since at least one electron source is provided for each pixel, the area required for scanning one electron source is small, and the distance that the electron beam travels from the electron source is not required. . Therefore, it is not necessary to make it as thick as a CRT display, and it is possible to make it as flat as a liquid crystal display.

(Example) Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

Figures 1 and 2 are for explaining one embodiment of the present invention, respectively. Figure 1 is a diagram showing the schematic structure of a unit light emitting element, and Figure 2 is a flat panel display using this element. FIG. 1 is a plan view showing the overall configuration of the device.

First, the configuration of a unit light emitting element will be explained with reference to the plan view of FIG. 1(a). At the center of the unit light emitting element, an electron emitting emitter 12 of a field emission mechanism is formed, for example, by silicon micromachining technology. Four control electrodes 14 are formed independently around the electron emitter 12 with an insulating film 13 in between. Four electron collector electrodes 15 having different areas are formed around the control electrode 14 with an insulating film 13 in between. A light-emitting thin film 16 that is excited and emits light by an electron beam is formed on the collector electrode 15.

The potentials applied to the electron collector electrode 15 are R and G, respectively.
, B to obtain an electron beam with energy suitable for the material of the light emitter. The area of the electron collector electrode 15 on which R, G, and B light emitting films are formed is the same as that of each light emitting thin film 1.
6, it is formed in proportion to the product of the luminous efficiency for the electron beam with each energy and the human visual sensitivity.

An electronic shield 17 consisting of one electrode is formed around the electron collector electrode 15 with an insulating film 13 interposed therebetween. This electronic shield 17 includes each electron collector electrode 15.
It is also formed between the electrodes 15, and not only isolates the unit light emitting elements but also isolates the electron beam between the electrodes 15.

Next, the structure of the unit light emitting element will be explained with reference to the cross-sectional view of FIG. 1(b). An electron emitting emitter 12 is formed on a substrate 11, and the substrate 1 excluding this emitter 12 is
An insulating film 13 is formed on top of the insulator film 1 . A control electrode 14 is placed on this insulator film 13. An electron collector electrode 15 and an electron shield 17 are formed, and a light emitter thin film 16 is further formed on the electron collector electrode 15.

Above the substrate 11, a transparent sealing body 18 made of, for example, glass is arranged to face the substrate 11, and the space between them is kept in a vacuum. Although not shown in the figure, the substrate 1
1 includes a driving element and a driving circuit, each driving element having an electron emission emitter 12 . Control electrode 14
゜Electrically connected to the electron collector electrode 15.

In addition, since the potential of the electronic shield 17 does not need to be constant,
There is no need to connect each element.

Similar to an LCD, such unit light emitting elements 20 are arranged in a matrix as shown in FIG. 2, and are driven line by line by a driving section (not shown). That is, the drive element controls and selects the amount of emitted electrons, the potential difference, the color of the emitted light, etc., and the unit light emitting element is scanned by the drive circuit to output an image.

In the display device configured in this way, by appropriately setting the potential of each electrode 12, 14, 15, the electron beam emitted from the electron emitter 12 is guided to the electron collector electrode 15, and the electron beam on the collector electrode 15 is guided. The light emitter thin film 16 can be made to emit light. For example, the potential of each electrode can be changed to the electron emission emitter 12, a negative potential, and the control electrode 14.
is also at a negative potential, and the electron collector electrode 15 is R, G, and B, respectively.
It is assumed that the electron shield 17 has a positive potential suitable for the material of the light emitting body, and the electron shield 17 has a negative potential.

In this case, the electrons emitted from the electron emitter 12 are quantitatively controlled and deflected by the negative potential of the control electrode 14, and then sent to a certain electron collector electrode 15 due to the potential difference between the electron emitter 12 and the electron collector electrode 15. They collide with corresponding energy. At this time, collector electrode 1
The light emitting thin film 16 on the phosphor 5 is excited, and R,G.

A specific light B is emitted, and this light is emitted to the outside through the transparent sealing body 18.

Thus, according to this embodiment, not only does it function as a two-dimensional display device, but also the unit light emitting device is composed of an electron emitting emitter 12, a control electrode 14, and a control electrode 14, as shown in FIG. Since it is composed of the electron collector electrode 15, the light emitting thin film 16, etc., it has the following advantages. That is, since the light emitting mechanism is exactly the same as that of a CRT display, the performance of brightness and contrast is high. Furthermore, since one electron source is provided for one pixel, the surface that needs to be scanned by one electron source is small, and the distance that the electron beam travels from the electron source is not required to be large.

Therefore, it is not necessary to make it as thick as a CRT display, and it is possible to make it as flat as a liquid crystal display. In other words, it is possible to maintain brightness and contrast comparable to that of a CRT, while achieving flatness comparable to that of a liquid crystal display.

Next, various modifications of the unit light emitting device of the present invention are shown in FIGS. 3 to 8.

In the example shown in FIG. 3, an insulator film 31 is formed between the electron collector electrode 15 and the insulator film 13 below it, and the control electrode 1
The electron collector electrode 15 is lower than the insulator film (]3) under 4.
The insulator film (13, 31) below is formed thicker. This is to take into account the high potential applied to the electron collector electrode 15, improve withstand voltage characteristics, and reduce the influence of carriers induced on the surface of the substrate 11. In addition,
Although the insulating film under the electron collector electrode 15 has a multilayer structure, it may have a structure in which the negative layer of the insulating film is etched.

The feature of FIG. 4 is that an insulating film 13 is embedded in the surface of the substrate 11, and the electron emitter 12 is formed on the same surface as the control electrode 14. This is because the positional relationship between the electron emitter 12 and the control electrode 14 is sensitive to quantitative control of the electron beam density, so the electron beam density is increased at the expense of controllability. In this way, the positions of the electron-emitting emitter 12 and the control electrode 14 have suitable conditions depending on the requirements.

The features of FIG. 5 include the electron emission emitter 12 and the control electrode 14.
A second control electrode 32 is formed with an insulating film 13 interposed therebetween.

This causes emitted electrons to collide with the control electrode 14 and the second control electrode 32, which are set at a positive potential, to generate secondary electrons.
Its purpose is to multiply and deflect electrons. As mentioned above, an extremely large electric field is required to significantly deflect the trajectory of an electron beam that has enough energy to emit light without causing collisions. Therefore, in this embodiment, secondary electrons generated by colliding electrons are used to deflect the electrons in the lateral direction while multiplying the electrons.

The feature of FIG. 6 is that the second control electrode 3 in the example of FIG.
2, a third control electrode 33 is provided.

In this example, the control electrode 33 closest to the electron emission emitter 12 is given a negative potential to perform quantitative control using a blocking electric field for emitted electrons, thereby making it possible to quantitatively control the brightness.

The feature of FIG. 7 is that a portion 34 of the surface of the transparent sealing body 18 facing the substrate 11 is made conductive. In this case, by setting a positive potential on the conductive surface 34, electrons can collide with the surface 34 to generate secondary electrons, thereby multiplying and deflecting the electrons. In this example, since the energy of the electron beam necessary for light emission can be selected based on the potential difference between the conductive surface 34 and the electron collector electrode 15, there is an advantage that the degree of freedom regarding the potential of the electron-emitting emitter 12 is greatly increased. Furthermore, since it uses electron collision, it is possible to send electrons to the substrate side without applying an unreasonable electric field. Note that the conductive surface 34 may be at a constant potential throughout the device. The conductive surface 34 can also be formed, for example, by slightly reducing glass with heat in a hydrogen atmosphere and then etching away unnecessary portions.

In addition to the example of FIG. 7, the feature of FIG. 8 is that at least a portion 35 of the conductive surface 34 on which electrons collide is processed into a convex shape,
The purpose is to facilitate the horizontal deflection of secondary electrons. In this way, it is possible to keep the thickness of the vacuum part to 10 μm or less.

Note that the present invention is not limited to the embodiments described above. In the embodiment, the electron collector electrode in the unit light emitting element is divided into four parts, but it may be divided into three parts, one each of R, G, and B, or even into five or more parts. Furthermore, in the case of a monochrome display rather than a color display, there is no need to divide the electron collector electrode, and it is possible to use only one electron collector electrode to further simplify the structure of the unit light emitting element. In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As detailed above, according to the present invention, since a unit light emitting element is constituted by an electron emitting emitter, a control electrode, a collector electrode, a light emitting thin film, etc. formed on the surface of a substrate, it can be used as a CRT display. It is possible to realize a flat display device with brightness and contrast comparable to that of a liquid crystal display.

[Brief explanation of drawings]

Figures 1 and 2 are for explaining one embodiment of the present invention, respectively. Figure 1 is a diagram showing the schematic structure of a unit light emitting element, and Figure 2 is a flat panel display using this element. Plan views showing the overall configuration of the device, Figures 3 to 8
Each figure is a cross-sectional view of an element structure for explaining the present invention in detail, and FIG. 9 is a perspective view showing a schematic structure of a CRT display using a conventional channel multiplier system. DESCRIPTION OF SYMBOLS 11... Substrate, 12... Electron emission emitter, 13.31... Insulator film, 14.32.33... Control electrode, 15... Electron collector electrode, 16... Luminescent thin film , 17... Electronic shield, 18... Transparent sealing body, 20... Unit light emitting element, 34... Conductive surface, 35... Convex portion.

Claims (1)

[Scope of Claims] The unit comprises a plurality of unit light emitting elements arranged in a matrix on a substrate, and a transparent sealing body arranged facing the surface of the substrate and maintaining a region where the unit light emitting elements are arranged in a vacuum. The light-emitting element includes an electron-emitting emitter that is provided on the substrate and emits electrons when an electric field is applied, a control electrode that is provided near the emitter and controls the amount of electron beam emitted from the emitter, and this control electrode. It consists of an electron collector electrode provided at a position farther from the emitter than the emitter, and a light-emitting thin film provided on the collector electrode that emits light when excited by the electron beam, and adjacent unit light-emitting elements are separated by an electron shield. A display device characterized by: