JPH09134685A - Field emission element, and field emission display having function of touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify its device constitution by having both these functions by a single element though an FE element itself as a constitutive element has merely respectively and independently a display function and an input function so far in a sensor or a display using field electron emission (FE). SOLUTION: When voltage is impressed between an emitter E1 and a transparent electrode A1 of a positive electrode by a power source V1 , FE is generated, and an emitting electron excites a phosphor F1 so as to emit the light, and has a display function. A glass thin plate T1 formed as a diaphragm and the transparent electrode A1 change a relative position between electrodes by external force, and change an electric current by the emitting electron, and this electric current is detected by an electric current detecting part I1 . It follows that the external force has a touch input function by a finger. The emitting light by an FE electric current is controlled by the power source V1 , impression voltage on a gate electrode G1 and displacement of the electrodes formed into a diaphragm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission device, and more particularly, to a sensor,
Alternatively, the present invention relates to a field emission element having both an input function such as a touch panel and a display function, or a display.

[0002]

2. Description of the Related Art As a conventional technique, a device for reading a location on a display screen designated by a finger or the like is known as a pointing device on a display in which a touch panel is installed on the display device, and is designated on the display screen. There is known an input device configured to determine the content of input data designated in relation to a designated place. In this type of input device, a CRT, a liquid crystal display, or the like is used as a display device.

On the other hand, a field emission display (FED) is a display device which is expected to be used as a thin display device and is being actively studied at present (Japanese Patent Laid-Open No. 6-11).
1713 gazette). This FED has an electron source for each display pixel and has a display performance equivalent to that of a CRT.
The display device can be made thinner. Figure 6 shows this FE
It is a figure which shows the structure of the representative example of D. In the example shown in FIG. 6, the device is configured between 2 mm glass substrates B.
The electrons emitted from the emitter E into the vacuum move toward the transparent electrode A of the anode and excite the phosphor F to emit light of each color. Light emission is observed through the transparent electrode A and the glass substrate B, and forms a display screen as a whole.

Further, a field emission (field emission: F) is used as an element (sensor) for detecting a change in input state.
The application of E) is considered. This sensor is
This utilizes the change in emission current due to the change in the distance between the cathode and the anode that causes field emission as the state change. FIG.
It is a figure which shows the outline of a structure of an FE pressure sensor as an example of the sensor which applied FE. In the example shown in FIG. 7, an electrode is provided on the pressure receiving surface of the diaphragm D, and the diaphragm D is bent by pressure. The electrode of the diaphragm D is used as an anode, and the distance between the anode electrode and the cold cathode E changes according to the pressure change, and accordingly, the change of the electrons emitted from the cold cathode is detected by the ammeter I. Is configured.

Here, the current J ₀ emitted from the cathode by field electron emission is usually shown as follows.

[0006]

(Equation 1)

Therefore,

[0008]

(Equation 2)

Here, since the applied electric field F of the above equation 3 can be F = V / d from the relationship between the distance d between the cathode and the anode and the applied voltage V, if the work function φ is determined,

[0010]

(Equation 3)

Can be expressed using the distance d between the electrodes.

As described above, among the above-mentioned conventional techniques, the sensor senses a change in the state as a change in the distance between the electrodes and outputs a detection signal, which can be used as an input device. It has nothing to do with the display function by light emission used in the FED. And
The FED in the above-described conventional technology does not have the function of an input device such as a touch panel type pointing device in the FED itself, but only has the function of a display device. Furthermore, in the above-mentioned conventional display equipped with a touch panel, input on the display device is realized by combining different elements of the display device unit and the input device unit, but the device itself is independent of each other. There is a problem in that a simple and large-scale device is structurally and circuitly constructed by simply combining elements having the function of.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art. In an input device such as a sensor using field electron emission, the input state of the input device itself is set. In addition, the field emission display constituting the display surface is provided with the same input function as a touch panel, and the configuration is simplified as compared with the conventional display. The purpose is to do.

[0014]

According to the invention of claim 1, there is provided a field emission device having an electrode that contributes to field electron emission and a phosphor that emits light by electrons emitted from a cathode in the electrode. At least one of the electrodes is made movable so that the relative position between the electrodes is changed, and a field electron emission current is detected, and a driving voltage is applied to the electrodes so that electrons emitted from the cathode are phosphors. It has a display function by emitting light by exciting the fluorescent substance, and when one of the electrodes is moved by an external operation to change the relative position between the electrodes, the change in the state is displayed by the amount of light emission. In addition, the field electron emission current from the electrode can be detected and output.

According to a second aspect of the present invention, in the first aspect of the present invention, the electrode is composed of a cathode, an anode and a gate electrode, and a gate electrode is added as an element to have a display function and an input function. By expanding the range of functions as the element and selecting the gate electrode as a movable electrode, the degree of freedom in design is increased.

According to a third aspect of the invention, in the first or second aspect of the invention, the movability of the electrode is given by a diaphragm, and the displacement of the electrode operated by an external force and the force are constant. And is effective as a sensor or an input device.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the diaphragm is made up of a thin transparent substrate and a transparent electrode that are bent by an external force, and a means for embodying the diaphragm is provided. .

According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, the phosphor is applied to the anode, and means for embodying the arrangement of the phosphor is provided.

According to a sixth aspect of the present invention, the field emission devices according to any one of the first to fifth aspects are arranged in a one-dimensional or two-dimensional manner, and the field emission elements are arranged in relation to the light emission display on the display surface (screen). By pushing a designated place with a finger or the like, it becomes possible to generate input data having additional information corresponding to the designated position.

[0020]

FIG. 1 is a diagram illustrating a configuration of an embodiment of a field emission (FE) element or a field emission display (FED) according to the present invention. In the example shown in FIG. 1, a unit element of an FE element is formed between a glass substrate B ₁ and a glass thin plate T ₁ that also serves as a protective film and a lid of a vacuum container by a spacer S ₁ , and this unit element is formed. They are arranged to form an FED.

In this example, the emitter E ₁ extends from the cathode electrode C ₁ provided on the glass substrate B ₁ into the discharge space,
The counter electrode is constituted by the transparent electrode A ₁ which is an anode coated with the phosphor F ₁ through the space. The transparent electrode A
₁ is integrated with the glass thin plate T _1, and the integrated structure forms a diaphragm, and the relative position between the counter electrodes is variable due to the nature of this diaphragm.

In addition, the cathode electrode C ₁ and the anode A ₁ which are opposed to _{each other}
The power supply V ₁ and the current detection unit I ₁ are connected between the two. In the example of FIG. 1, the common power source and the current detection unit are connected to the counter electrode, but they may be independent of each other. The gate electrode G ₁ is an electrode that controls the emission of electrons from the emitter E ₁ .

The operation of the device in the embodiment of FIG.
When the power supply V ₁ voltage is applied between the opposing electrodes E ₁ and A _1, it occurs field electron emission, emitted electrons, phosphor F
It emits light by exciting ₁ and can see the light from the outside, so it has a display function. The brightness can be changed by changing the voltage of the power source V _{1 or} the voltage of the gate electrode G ₁ .

The constituent elements on the anode side which form the diaphragm are bent by pressure from the outside, etc., and the distance between the electrode and the emitter E ₁ is changed, so that the amount of emitted electrons is changed and therefore the emission brightness is changed. When the current occurs, the magnitude of the pressure or whether or not the FE element is under the action of the pressure (ON / OFF signal) is detected by detecting it in the current detector. Since this detection signal is used as an input signal to the external device, it also has an input function.

FIG. 2 shows the FE element or F according to the present invention.
It is a figure which illustrates the structure of other embodiment of ED. FIG.
In the example shown in Fig. 1, the power supply, the current detection unit and the gate electrode shown in Fig. 1 are omitted, but the difference in the illustrated components from Fig. 1 is that the cathode electrode C ₂ and the anode A ₂
The arrangement is reversed and the emitter E ₂ is provided on the cathode side element having the function of the diaphragm.

Further, an embodiment of a more detailed structure of the cathode electrode in which the emitter is arranged on the electrode side having the function of the diaphragm to which an external force is applied as shown in FIG. 2 will be shown.
FIG. 3 is a perspective view showing an outline of such a cathode electrode. As shown in FIG. 3, the cathode electrode C ₃ of the cross in the glass sheet T ₃ provided, the emitter E ₃ are arranged at intersections of the cross.

According to this structure, an input state such as an external pressure applied can be seen as a change in the light emission of the phosphor F ₂ on the anode A ₂ through the gap of the cathode electrode C ₃ ( (See FIG. 3).

FIG. 4 is a diagram illustrating the configuration of another embodiment of the FE element or FED according to the present invention. In the example shown in FIG. 4, an electrode having a diaphragm function is arranged on a glass thin plate T ₄ to which an external pressure is applied as an emission current control transparent electrode (gate electrode) G ₄ . The cathode electrode C ₄ and the anode (positive) electrode are arranged on opposite side surfaces of the spacer S ₄ on both sides, and emitted electrons move between the opposite electrodes through a variable space created by the physical gate P ₄ and the gate electrode G ₄ . To do. Also in this example, the generation of the emitted electrons flowing between the counter electrodes is controlled by the gate electrode G ₄ bending due to the external pressure, and the change can be displayed and detected as an input signal.

FIG. 5 is a diagram showing an outline of an embodiment of the present invention in which FE elements are two-dimensionally arranged (which can be understood as including one dimension) to form an FED. As shown in FIG. 5, as a two-dimensional array example, the emitters E ₅ are regularly arranged in rows in the horizontal and vertical directions to form a panel to form a panel.

In this example, a simple matrix system is adopted, and when a video signal is input to the display drive circuit DD,
The display drive circuit DD outputs an X address to the horizontal shift register HSR and a Y address to the vertical shift register VSR, applies a drive voltage corresponding to these XY addresses to the emitter E ₅ of each FE element, and emits an emission current. generate. The FE element emitted by the operation of the display drive circuit DD forms a display image forming a panel.

In the above operation, the emission current is sequentially detected by the current detector I ₅ simultaneously with the driving of the display, and the detected value is associated with the X and Y address information output from the display drive circuit DD. This makes it possible to know which position on the panel generates what kind of emission current. Since the FE element has a touch panel input function using a diaphragm as described above, it is possible to detect which position on the panel is touched from the state of this emission current. , XY position input device and sensor is effective.

[0032]

【The invention's effect】

Effect of claim 1: As an FE element, the emission is controlled by controlling the field electron emission from the cathode to have a display function. Further, since at least one of the electrodes contributing to the field electron emission of this FE element is movable to change the relative position between the electrodes, an input function is provided in which this change is input and the emission current is output. Further, when using this input function, the input state can be confirmed by a light emitting display. Then, an apparatus having both a display function and an input function with a simple and compact structure of the FE element is provided.

Effect of claim 2: In addition to the effect of claim 1, the display function and the input function can be widened by including a gate electrode as an electrode contributing to field electron emission. In addition, the degree of freedom in designing the device is increased.

Effect of Claim 3: In addition to the effects of Claims 1 and 2, the diaphragm that gives the electrode mobility is operated so that a force applied from the outside and a displacement of the electrode have a constant relationship. Therefore, an effective means as a sensor or an input device is provided.

Advantageous effect of claim 4: In addition to the advantageous effect of claim 3, by providing a diaphragm embodying means, an FE element which can be more easily put into practical use is provided.

Effect of claim 5: In addition to the effects of claims 1 to 4, an FE element which is easy to put into practical use can be provided by providing effective means for arranging the phosphor as a light emitter. Will be provided.

Effect of claim 6 In addition to the effects of claims 1 to 5, an image can be displayed on the one-dimensional or two-dimensional screen of the FED panel, and the element position (X, Y position) on the screen can be displayed. The coordinates) and the input state (touch or magnitude of applied force) of the element can be input. Further, at the time of input, since the input can be confirmed in the light emission display state of each element of the FED panel, it is possible to prevent an input error.

[Brief description of the drawings]

FIG. 1 shows the field emission (F
It is a figure which illustrates the structure of embodiment of E) element or a field emission display (FED).

FIG. 2 is a diagram illustrating the configuration of another embodiment of an FE element or FED according to the present invention.

FIG. 3 is a perspective view showing an outline of a cathode electrode having a diaphragm function.

FIG. 4 is a diagram illustrating a configuration of another embodiment of an FE element or FED according to the present invention.

FIG. 5 is a diagram showing an outline of an embodiment of the present invention which constitutes an FED in which FE elements are two-dimensionally arranged.

FIG. 6 is a diagram showing a structure of an example of a conventional FED.

FIG. 7 is a diagram showing an outline of a configuration of an FE pressure sensor as an example of a sensor to which FE is applied.

[Explanation of symbols]

A, A ₁ ... transparent electrode (anode), A ₂ ~A ₄ ... _{anode, B, B 1, B 2} , B 4 ... glass substrate, C, C ₁ ~
C ₄ ... Cathode electrode, D ... Diaphragm, E, E _{1 to} E ₅
... emitter, F, F ₁ to F ₄ ... phosphor, G, G ₁ ... gate electrode, G ₄ ... emission control transparent electrode (gate electrode),
I, I ₁ , I ₅ ... Current detection unit, S ₁ , S ₂ , S ₄ ... Spacer, T ₁ , T ₂ , T ₄ ... Glass thin plate, V, V ₁ ... Power supply, DD
... Display drive circuit, VSR ... Vertical shift register, HSR
... A horizontal shift register having a current detection function.

Claims (6)

[Claims] 1. In a field emission device having an electrode that contributes to field electron emission and a phosphor that emits light by electrons emitted from a cathode in the electrode, a relative position between the electrodes is changed. A field emission device characterized in that at least one of the electrodes is movable and a field electron emission current is detected. 2. The field emission device according to claim 1, wherein the electrode comprises a cathode, an anode and a gate electrode. 3. The movability of the electrode is provided by a diaphragm.
Field emission element described. 4. The field emission device according to claim 3, wherein the diaphragm is composed of a thin transparent substrate and a transparent electrode that are bent by an external force. 5. The field emission device according to claim 1, wherein the phosphor is applied to an anode. 6. A field emission display having a touch panel function, characterized in that the field emission elements according to any one of claims 1 to 5 are arranged one-dimensionally or two-dimensionally.