JPH10148829A - Plane type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plane type display device which is high in fineness, luminance and contrast and is low in electric power consumption. SOLUTION: Plural rows of cathode electrodes 34 are arranged on a glass substrate 32 and very small cold cathodes 38 are arranged on these cathode electrodes 34 in a matrix form. Insulation layers 40 having the bores to enclose the cold cathodes are formed on the cathode electrodes 34 and plural columns of gate electrodes 36 orthogonal with the cathode electrodes 34 are formed on these insulation layers 40. The intersection points of the cathode electrodes 34 and the gate electrodes 36 are made to pixels. A glass plate 42 is disposed apart from the gate electrodes 36 and an anode electrode 44 is formed over the entire surface of the cold cathode side front surface of this glass plate 42. Phosphors 46 are formed by every pixel on the cold cathode side front surface of this anode electrode 44. Liquid panel parts 60 for controlling the transmission quantity of the light emitted by each of the respective pixels are arranged thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display device utilizing light emission from a phosphor excited by an electron beam.

[0002]

2. Description of the Related Art A typical flat panel display device is a liquid crystal display device. This is currently widely used as a display device of a notebook personal computer. However, the liquid crystal display device is a display device that displays an image by modulating (controlling) the amount of transmitted light without emitting light by itself, and therefore requires a light source (backlight) on the back surface. Since this backlight light source is required, there are various disadvantages such as high power consumption, low contrast, and low peak luminance.

FIG. 1 shows an example of a conventional liquid crystal display device with a backlight. A diffusion plate 12 under the liquid crystal display panel 10;
A light guide plate 14 is provided. A fluorescent lamp 16 is arranged at one end of the light guide plate 14. The direct light from the fluorescent lamp 16 and the light reflected by the reflection plate 18 are incident on the light guide plate 14, are reflected upward by the reflection plate 20 below the light guide plate 14, and are diffused above the light guide plate 14. The light is incident on the entire surface of the panel 10 through the panel 12. Since the liquid crystal display panel 10 as an optical modulator is publicly known, a detailed description thereof is omitted. However, the liquid crystal display panel 10 has a transparent pixel electrode and controls on / off of a light transmission amount for each pixel.

[0004] The fluorescent lamp 12 is a tube in which an inert gas is sealed, and when a voltage is applied, plasma is generated in the tube to generate ultraviolet rays. The ultraviolet rays collide with the phosphor applied on the inner wall of the tube, and the phosphor is excited to emit light.

As described above, a conventional fluorescent lamp as a backlight of a liquid crystal display device has a very low luminous efficiency and high power consumption because ultraviolet rays for exciting a phosphor are generated by generating plasma. There was a problem. In addition, since the entire surface of the liquid crystal display panel emits light so that light is incident on the entire surface of the liquid crystal display panel, the light is incident even on a pixel that is not performing display. In addition, since light of uniform brightness is incident on the entire surface of the liquid crystal, the contrast ratio is low, and even if the brightness of a pixel at a specific location is made extremely bright, the brightness of the backlight becomes uniform. There is a problem in that it is limited and high peak luminance cannot be obtained.

On the other hand, a field emission display (F) has been proposed as a flat display device for solving the drawbacks of the liquid crystal display panel.
ED) devices have recently been developed. One example is Micr
otips Fluorescent Display, IEDM 91, pp 197-200. The field emission cold cathode electron source used in this device is the same triode as a conventional vacuum tube, but without using a hot cathode, it concentrates a high electric field on a sharp cathode (emitter) and performs quantum mechanical tunneling. The difference is that a cold cathode that extracts electrons due to the effect is used. Then, electrons extracted from the cold cathode are accelerated by the voltage between the anode and the cathode and collide with the phosphor film formed on the anode to excite the phosphor film to emit fluorescence. As described above, this display device is the same as a conventional CRT in terms of excitation and emission of a phosphor by a cathode ray, and can obtain a wide viewing angle of 180 ° in principle. However, while the CRT uses a point electron source, the FED uses a planar matrix electron source composed of a micron-sized (1-2 μm) micro cold cathode array for each pixel. As a structure of a phosphor for color display, a phosphor layer of three colors of RGB is applied on a uniform ITO layer serving as an anode on a glass substrate.
There are two types: a switched anode and a switched anode that separately forms an anode electrode layer for each of the three RGB phosphors and sequentially and selectively excites the RGB phosphors. The latter has the advantage that there is no need to form a cathode for each of the RGB pixels; the alignment between the anode and the cathode is simple.

However, the cold cathode itself has been miniaturized,
Although it is possible to make a minute one, it has been difficult to make the phosphor ultra-fine (to achieve a resolution comparable to a photograph). The reason is that it is difficult to separately form RGB three-color phosphors for each minute pixel due to the restriction on the particle size of the phosphor; in order to improve the contrast, the phosphor pixels are bordered with carbon, so-called black. It is difficult to achieve high definition because a matrix is formed.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a flat-panel display device having high definition, high brightness, high contrast and low power consumption. . Another object of the present invention is to provide a liquid crystal display device which uses a backlight having a high luminous efficiency, enhances the use efficiency of light from the backlight to reduce overall power consumption, and has a high contrast ratio and a high peak luminance. Is to provide. Another object of the present invention is to provide a field emission display (FED) device that inherits the characteristics of a CRT and enables ultra-high definition.

[0009]

In order to solve the above problems and achieve the object, the present invention uses the following means. A display device according to the present invention includes a light source including a plurality of light source elements, a light modulator including a plurality of light modulation elements into which light from each light source element is incident and selectively transmitting light, the light modulation element and the light source element Wherein each light source element has a field emission type cold cathode, an anode electrode arranged opposite to the cold cathode, and a cold cathode side surface of the anode electrode. And a phosphor that emits light by electrons emitted from the cold cathode toward the anode electrode.

According to the display device of the present invention, the light generated by colliding electrons emitted from the cold cathode by the quantum mechanical tunneling phenomenon with the phosphor is used as the light source of the image display device. Instead of generating plasma and then generating ultraviolet light to excite the phosphor as in a backlight of a display device, electrons are directly collided with the phosphor to emit light with high efficiency. In addition, since light is emitted by emitting electrons only from the cold cathode at a portion corresponding to a pixel to be displayed, light use efficiency is high and power consumption is low. Furthermore, since the cold cathode is used, the amount of current of the electron beam can be extremely large. Also, since a minute electron beam can be formed, only a desired point or area of the screen can be selectively and brightly emitted, and the peak luminance can be obtained. It is possible to increase the contrast ratio.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a flat panel display according to the present invention will be described with reference to the drawings. (First Embodiment) FIG. 2 is a perspective view showing a configuration of a liquid crystal display device according to a first embodiment of the present invention. This liquid crystal display device includes a light source unit (backlight) 30 and a liquid crystal panel unit 6.
0.

First, the configuration of the light source unit 30 will be described. On a glass substrate 32, a plurality of cathode electrodes 34-
Are arranged along the row direction. 1
The cathode electrodes 34 correspond to one row of pixel columns. In the present embodiment, for color display, R, G, B
One display pixel is formed from these three pixels.
The term “pixel” simply refers to the former. Cathode electrode 34-
, 34-2,..., A plurality of gate electrodes 36-1, 3-2 in a direction orthogonal to the cathode electrode via the insulating layer 40.
6-2, 36-3,... Are arranged along the column direction. The intersection of the cathode electrode 34 and the gate electrode 36 corresponds to one pixel. The gate electrodes 36-1, 36-2, 36-3,... Located on the cathode electrodes 34-1, 34-2,. Is formed by etching or the like. On the cathode electrodes 34-1, 34-2,..., A small conical cold cathode 38, for example, a conical cold cathode 38 is inserted so as to enter this hollow.
Are formed. The cold cathode serves as a light source of the liquid crystal display panel. In principle, one cold cathode is sufficient for each pixel. (In practice, there are usually several hundreds to thousands of cold cathodes.) A cold cathode 38 is provided as a light source for one pixel to provide redundancy.

A glass plate 42 is spaced apart from the above structure. An anode electrode 44 made of, for example, a light-transmitting ITO film is formed on the entire surface (lower surface) of the glass plate 42 on the side of the cold cathode 38. On the surface (lower surface) of the anode electrode 44 facing the cold cathode, a phosphor 46 is provided for each pixel. That is, a large number of phosphors 46-1-1, 46-1-2, 46-2-1,... Are formed in a matrix above the position where the cathode electrode 34 and the gate electrode 36 intersect.

Although not shown, the cathode electrode 34,
The gate electrode 36 and the anode electrode 44 are connected to a light source driving circuit, and a voltage is applied from the light source driving circuit. Phosphor 4
Numeral 6 is formed of a mixed fluorescent material including a plurality of types of fluorescent materials that emit white light as a whole when electrons collide. In addition, it may be formed of one kind of fluorescent substance that emits white light. For example, the phosphor 46 is formed of a spherical fine particle phosphor.

In order to obtain a high-definition color image display device, a fluorescent surface in which two or more kinds of phosphors having different emission colors are superposed in a multilayer is provided, and the magnitude of the acceleration voltage of the electron beam is reduced. A so-called penetration phosphor, which changes the emission color by changing the penetration depth of the electron beam into the phosphor particles by changing it, may be used. Further, a similar concept is used to form a phosphor screen in which two or more phosphors having different emission colors are stacked in a multilayer, or a so-called penetration phosphor screen in which a dielectric layer of a non-light emitting surface is sandwiched between these phosphor layers. Is also good.

A method for manufacturing the cold cathode 38 will be described. This embodiment employs a transfer molding method. The transfer molding method will be described with reference to FIGS. As shown in FIG. 3A, the (100) Si substrate 200 is anisotropically etched using a thermally oxidized SiO ₂ mask using a 30% KOH aqueous solution, and a very sharp triangular pyramid, that is, a mold is formed. It is formed. Unlike the conventional manufacturing method using Si anisotropic etching, this etching process stops automatically. Therefore, many molds can be formed uniformly and with good reproducibility. The width of the opening is usually 1.0 to
3.0 μm. After removing the SiO ₂ mask, S
The i-mold is thermally oxidized to form a high quality emitter-gate insulating layer 202 with little leakage. Thermal oxidation S
resistance iO ₂ layer 203 is 2 to 3 times the SiO ₂ layer was deposited. In the process of growing the thermally oxidized SiO ₂ layer 203, the shape of the SiO ₂ layer on the side wall of the mold becomes convex. LaB ₆ , Ti
The emitter layer 204 such as N
Deposited on _two layers and filled into the mold. The shape of the emitter chip on the bottom surface of the mold is sharp as shown in FIG. Further, an ITO layer 206 is formed by sputtering. Then, as shown in FIG. 3C, the emitter layer is bonded to the glass substrate 208 having the Al back electrode 210 by applying several hundred volts of DC.

In order to remove the Si mold substrate and the SiO ₂ layer, as shown in FIG. 3D, anisotropic Si etching using a tetramethylammonium hydroxide (TMAH) solution and SiO ₂ etching using a buffered HF solution. Is performed. The SiO ₂ layer 202 acts as an etch stop for the TMAH solution. Therefore, the emitter array is transferred from the Si substrate to the glass substrate. The emitter tip is essentially sharpened during the process and does not need to be sharpened after formation.

To form a gate-emitter array,
The following process is required. As shown in FIG.
Gate array 212 and resist layer 214 are applied over SiO ₂ layer 202 that was not removed during the gate fabrication process. As shown in FIG. 4B, the thin resist layer 2
14 is dry-etched in an oxidizing plasma, and the applied resist layer 214 is exposed only at the tip of the emitter portion. The gate electrode 212 is opened by wet etching so as to expose a part of the thermally oxidized SiO ₂ layer 202 (FIG. 4C).
_{The two} layers are wet-etched so that the tip of the emitter 204 is exposed (FIG. 4D). As a result, a submicron opening is formed in the center of the gate of the emitter.

Next, the configuration of the liquid crystal panel section 60 formed on the light source section 30 will be described. This liquid crystal panel section 6
Reference numeral 0 denotes a known liquid crystal display panel driven by active matrix driving. The switching element for performing the active matrix driving may be a thin film diode (TFD) type or a thin film transistor (TFT) type. The driving method may be simple matrix driving instead of active matrix driving.

A first polarizer 62 that passes only a linearly polarized light component is disposed immediately above the light source unit 30, and a glass substrate 64 is disposed above the polarizer 62. Glass substrate 6
4, a large number of phosphors 46-1-1, 46 of the light source unit 30
, A large number of transparent pixel electrodes 66-1-1, 66-1-2, 66-2- at positions corresponding to -1-2, 46-2-1,...
Are arranged in a matrix. Although the drawing is complicated and difficult to understand, and is a well-known matter, although not shown, a pixel signal 66 is provided on the pixel electrode 66 similarly to a normal active matrix type liquid crystal display element. A switching element for connecting the electrode, the signal electrode and the pixel electrode 66, a scanning electrode for controlling ON / OFF of the switching element, and a liquid crystal driving circuit connected to the signal electrode and the scanning electrode and applying a voltage to both electrodes are provided. Is provided. That is, a switching element is provided for each pixel electrode 66, and a plurality of rows of scanning electrodes for controlling on / off of the switching element are arranged in the row direction.
A plurality of columns of signal electrodes for applying a voltage to each pixel electrode 66 are arranged in a direction orthogonal to the direction in which the scanning electrodes extend, that is, in the column direction.

A glass substrate 68 is spaced above the glass substrate 64. Glass substrate 64 of glass substrate 68
A red filter 70-1, a green filter 70-2, and a blue filter 70-3 corresponding to each pixel are provided on the side surface (lower surface).
Are repeatedly formed to form a color filter layer 70. A transparent common electrode 72 is formed on the surface of the color filter layer 70 (facing the glass substrate 64). A liquid crystal layer 74 filled with liquid crystal is formed between the glass substrate 64 and the common electrode 72. Glass substrate 6
Surface opposite to color filter layer 70 (upper surface)
Is provided with a second polarizer 76 that passes only the linearly polarized light component. The linearly polarized light component passing through the second polarizer 76 and the linearly polarized light component passing through the first polarizer 62 are arranged in an orthogonal relationship.

The cathode electrode 34 and the gate electrode 36
, The arrangement position of the phosphor 46, and the pixel electrode 66
Are arranged so as to overlap the same position.
The operation of this embodiment will be described. First, the light emission of the light source unit 30 will be described. As in the case where a conventional fluorescent tube is used, full-surface light emission can be performed. However, since a light source (cold cathode) is provided for each pixel, an operation for controlling light emission for each pixel so as to improve luminous efficiency can be performed. explain.

A voltage is applied to the anode electrode 44 and one cathode electrode 34-i. When a voltage is applied to one gate electrode 36-j, electrons are emitted from the cold cathode 38 at the intersection of the cathode electrode 34-i to which the voltage is applied and the gate electrode 36-j, and the electrons are cooled. Cathode 38
The phosphor 46-ij emits light by colliding with the phosphor 46-ij provided on the upper part of. Thus, by selecting the cathode electrode and the gate electrode,
The phosphor can emit light for each pixel located at the intersection.

As described above, according to the present embodiment, the light generated by colliding the electrons emitted from the cold cathode 38 by the quantum mechanical tunneling phenomenon with the phosphor 46 is used as the backlight of the liquid crystal display panel 60. Therefore, unlike the conventional example using a fluorescent tube, light emission can be performed without generating plasma, and light emission is performed with high efficiency. In addition, light can be emitted by emitting electrons only from the cold cathode at a portion corresponding to a pixel to be displayed. By controlling a backlight for each pixel, light use efficiency is high and power consumption is low. Furthermore, since a cold cathode is used, the amount of current of the electron beam can be extremely large. Also, since a minute electron beam can be formed, only a desired point or area of the screen can be brightly illuminated. Can be increased.

Next, the operation of the liquid crystal panel section 60 will be described. Linearly polarized light is extracted from the light emitted from the phosphor 46 by the polarizer 62. The liquid crystal layer 74 is sandwiched between the common electrode 72 and the pixel electrode 66, and is turned on / off according to application / non-application of a voltage between the two electrodes. Liquid crystal layer 7
Reference numeral 4 denotes a TN (Twisted Nematic) liquid crystal, for example.
In the off state, the molecular arrangement is twisted by 90 °, and the polarization plane of the incident light is rotated by 90 ° along this twist. In the ON state in which a voltage is applied between both electrodes, the twist is released, the molecules rearrange in the direction of the electric field, and the plane of polarization does not rotate. Therefore, when the liquid crystal layer 74 is in the off state, the linearly polarized light that has passed through the lower polarizer 62 is rotated by 90 ° in the liquid crystal layer 74 and can pass through the upper polarizer 76, and the display pixel is in a bright state. .
However, when the liquid crystal layer 74 is turned on, the linearly polarized light that has passed through the lower polarizer 62 cannot pass through the upper polarizer 76 whose polarization direction is shifted from the lower polarizer 62 by 90 °.
The display pixel is in a dark state. Therefore, when a voltage is applied to the scanning electrode, a switching element connected to the pixel electrode 66 is turned on, and a signal corresponding to image data is input from the signal electrode to the pixel electrode 66, the pixel is controlled according to the input signal. The liquid crystal layer 7 filled between the electrode 66 and the common electrode 72
4 is turned on / off for each pixel, and the amount of light transmitted through the liquid crystal layer 74 can be controlled (modulated).

The light that has passed through the liquid crystal layer 74 is colored R, G, or B by the color filter layer 70. The above description is about the display of one pixel. Next, the display of an actual image will be described.

First, a voltage is applied to one scanning electrode and a voltage is applied to the common electrode 72 so as to turn on the switching element corresponding to the pixel electrode 66 arranged in a certain row. Then, from all the signal electrodes to the pixel electrodes 66
, 66-1-2, 66-1-3,... Are simultaneously applied with signal voltages corresponding to image data. Thereby, the pixel electrodes 66-1-1, 66-1-2, 66-1
The liquid crystal layer 74 between -3,... And the common electrode 72 is turned on and off in accordance with the image data, respectively. . At this time, in the light source unit 30, the anode electrode 44
To the pixel electrode 66 of the selected row.
-1, 66-1-2, 66-1-3,... Corresponding to the cathode electrode 34-1 and the gate electrode 36-1,
A voltage is applied to each of the pixels 36-2, 36-3,..., And electrons are emitted from the cold cathodes 38 of the intersecting pixel portions. Therefore, the light source drive circuit and the liquid crystal drive circuit are linked. When the emitted electrons collide with the phosphor 46, the phosphor 46 emits white light. The white light from the phosphor 46 becomes linearly polarized light when passing through the polarizer 62 and enters the liquid crystal layer 74. The incident light rotates according to the on / off state of the liquid crystal layer 74. When the liquid crystal layer 74 is in the off state, the incident light rotates by 90 °, is colored by a color filter, and passes through the second polarizer 76. In this manner, display of one row is performed while sequentially applying signal voltages corresponding to image data to the RGB pixel electrodes of one row from the signal electrodes, and display of the next row is also performed sequentially.

A signal voltage is simultaneously applied to the pixel electrodes 66 connected to one row of scanning electrodes. The liquid crystal layer 74 between the pixel electrodes 66 and the common electrode 72 adjusts the rotation angle of the liquid crystal for a while. Even if light is sequentially emitted from the backlight panel unit 30 for each pixel, an image corresponding to the data for each pixel is displayed on the liquid crystal panel 60 because it is held.

As described above, according to the liquid crystal display device of the present embodiment, a field emission array for causing electrons to directly collide with a phosphor to emit light without using a conventional fluorescent lamp as a backlight light source is used. Since there is no need to generate plasma and emit ultraviolet light, luminous efficiency is high and power consumption is reduced. In addition, unlike the conventional full-surface light emission of a fluorescent lamp, light emission is performed for each pixel to be displayed, so that power consumption is further reduced and, at the same time, contrast is improved. Further, since the cold cathode capable of obtaining a large current density is used, the peak luminance can be increased and the contrast can be further improved. Further, a light source thinner than a fluorescent lamp can be obtained.

This embodiment can be implemented by being modified as follows. For example, when light emission is performed, in the above description, light emission is sequentially performed for each pixel, but voltage is applied to all the gate electrodes 36. Alternatively, driving may be performed in which electrons are simultaneously drawn from all the cold cathodes formed on one cathode electrode 34 and light is emitted for each row. When this driving is performed, as shown in FIG. 2, a plurality of rows of gate electrodes 36-1, 36-2,.
May be formed over the entire surface of the insulating layer 40.

Although the phosphor 46 is formed for each pixel electrode, it may be formed on the entire surface of the anode electrode 44.
The phosphor does not have to emit white light as long as color display is enabled by the color filter layer. For example, light emission of the same color as the color filter, for example, red, green, or blue light may be used. In the case of a monochrome image display device, single color light emission of green, orange, or the like may be used. As the color filter layer, a filter of a color other than red, green, and blue can be used as long as color display can be performed. Further, if the phosphor emits red, green and blue components, no color filter is required.

The present embodiment is not limited to a direct-view display device, but may be applied to a projection display device. That is,
Although the liquid crystal projector uses a halogen lamp or the like as a light source, the light source unit 30 of the present embodiment may be used instead of the halogen lamp. When the backlight unit of the present invention is used for a projector, power consumption is reduced, a cooling fan is not required, the thickness of the entire apparatus is reduced, and a high-intensity point light source is also possible. It has effects such as no image distortion.

In the embodiment, a liquid crystal panel is used as an optical modulator for controlling the amount of transmitted light. However, a plurality of pixels for controlling the amount of transmitted backlight are arranged in a matrix, and the amount of transmitted light is determined for each pixel. It is also possible to use a device other than the liquid crystal panel as long as it has means for controlling the display.
For example, PLZT (Lead Lanthanum Zirconate Titanat
An optical modulator composed of an optical modulation element using e) can also be used.

The phosphor may not emit white light, but may emit light of a color (for example, red, green, or blue) corresponding to the pixel. In this case, the color purity may be poor. (Second Embodiment) FIG. 5 is a perspective view showing a configuration of a field emission array type display device according to a first embodiment of the present invention. In the present embodiment, the light source unit 3 of the first embodiment is used.
This embodiment differs from the first embodiment in that a color liquid crystal shutter 100 is provided on the display panel 0 instead of the liquid crystal panel section 60. The color liquid crystal shutter 100 includes a first polarizing filter 102, a first liquid crystal panel 104 for each pixel, a second polarizing filter 106, and a second
, And a third polarizing filter 110. The first polarizing filter 102 is a neutral polarizing plate, and transmits R, G, and B having a plane of polarization in the horizontal direction. The second and third polarizing filters 106 and 110 are color polarizing plates. The second polarizing filter 106 transmits B having a plane of polarization in the horizontal direction and R and G having planes of polarization in the vertical direction. The polarizing filter 110 transmits R having a plane of polarization in the horizontal direction and B and G having planes of polarization in the vertical direction. The first and second liquid crystal panels 104 and 108 are formed by using the color filter layer 7 from the liquid crystal panel unit 60 of the first embodiment.
0, the polarizers 62 and 76 are removed. When ON (when a voltage is applied), the polarization plane remains as it is, and when OFF (when no voltage is applied), the polarization plane rotates 90 °. Then, the incident light is transmitted.

That is, in the second embodiment, the first and second liquid crystal panels 104 and 108 are selectively turned on and off for each pixel, so that the white light from the light source unit 30 is converted into any one of RGB color components. Display a color image by coloring. First,
When the second liquid crystal panels 104 and 108 are on and off, only a component having a plane of polarization in the horizontal direction of the white light emitted from the light source passes through the first polarizing filter 102. Then, since the first liquid crystal panel 104 is on,
The light passes through the polarization plane as it is, and passes through the second polarization filter 106.
Incident on. Since the second polarizing filter 106 transmits only B having a color having a plane of polarization in the horizontal direction, only B passes through here and enters the second liquid crystal panel 108. Since the second liquid crystal panel 108 is off, the polarization plane is changed to 9 here.
The light is rotated by 0 °, becomes B having a plane of polarization in the vertical direction, and enters the third polarizing filter 110. Since the third polarizing filter 110 transmits B having a polarization plane in the vertical direction, the light transmitted through the third polarizing filter 110 becomes B.

Similarly, the first and second liquid crystal panels 104,
When the switch 108 is off and on, the light transmitted through the third polarizer 110 is G, and the first and second liquid crystal panels 104 and
When both 108 are off, the light transmitted through the third polarizing plate 110 is R.

As described above, according to the second embodiment, by changing the voltage applied to the color liquid crystal shutter in accordance with the image signal, monochromatic light with high color purity and high precision can be extracted. In addition, since only monochromatic light can be extracted, a high contrast can be obtained. Therefore, there is no need to form a black matrix, and the resolution is determined only by the field emission array and the liquid crystal panel. Therefore, an ultra-high definition flat display device is provided. The light source unit 30
The characteristics of low power consumption, high brightness, and high contrast resulting from the above are similarly achieved in the second embodiment. The second embodiment can be modified and implemented similarly to the first embodiment.

[0038]

As described above, according to the image display device of the present invention, the electrons emitted from the cold cathode by using the quantum mechanical tunnel effect whose energy conversion efficiency is basically 100% are converted to the phosphor. Light generated by the collision is used as a light source of the image display device. Therefore, since light is emitted by directly colliding electrons with the phosphor without generating plasma, light is emitted with high efficiency. In addition, since light is emitted by sequentially emitting electrons from the cold cathode at a portion corresponding to a pixel to be displayed, light use efficiency is high and power consumption is low.

Further, since a cold cathode is used, the amount of electron beam current can be extremely large. Also, since a minute electron beam can be formed, a desired point or area on the screen is illuminated brightly, and the peak luminance and the contrast ratio are increased. It becomes possible to do.

Furthermore, the fluorescent screen is not necessarily red, green and blue.
There is no need to apply different colors, and a high-definition image display device can be obtained in combination with the micron-sized small cold cathode. The present invention is not limited to the embodiments described above, and can be implemented with various modifications.

[Brief description of the drawings]

FIG. 1 is a diagram showing a conventional example of a liquid crystal display device with a backlight.

FIG. 2 is an exploded perspective view showing a configuration of a liquid crystal display device as a flat panel display device according to a first embodiment of the present invention.

FIG. 3 is a diagram for explaining a method of manufacturing the cold cathode array according to the first embodiment.

FIG. 4 is a diagram illustrating a method for manufacturing the cold cathode array according to the first embodiment.

FIG. 5 is an exploded perspective view showing a configuration of a field emission array type display device as a display device according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 30 light source unit 60 liquid crystal panel unit 32 glass substrate 34-1, 34-2 cathode electrode 40 insulating layer 36-1, 36-2, 36-3 gate electrode 38 cold cathode 42 glass plate 44 ... Anode electrode 46-1-1, 46-1-2, 46-2-1 ... Phosphor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G09G 3/36 G09G 3/36 H01J 31/12 H01J 31/12 C

Claims (14)

[Claims] 1. A light source comprising a plurality of light source elements, wherein each light source element is a field emission cold cathode, an anode electrode disposed opposite to the cold cathode, and a cold cathode side of the anode electrode. And a phosphor that emits light by electrons emitted from the cold cathode toward the anode electrode, and receives light from the light source elements to adjust the amount of light transmitted from each light source element. A flat panel display device comprising an optical modulator. 2. The light emitting device according to claim 1, wherein the phosphor emits light in one of white and three primary colors of display, and the light modulator receives light from the light source element and has a first linear polarization plane. And a light modulating layer that receives light from the first polarizer, rotates a polarization plane of the incident light by a predetermined angle according to data to be displayed, and receives light from the light modulating layer. A color filter for coloring incident light into any one of the three primary colors of display; and a second linear polarization plane to which light from the color filter is incident and different from the first linear polarization plane by the predetermined angle. The flat panel display according to claim 1, further comprising a second polarizer. 3. The first polarizer having a first linear polarization plane, wherein the phosphor emits light in one of the three primary colors of display, and the light modulator receives light from the light source element. A light modulating layer that receives light from the first polarizer, rotates a polarization plane of the incident light by a predetermined angle according to data to be displayed, and receives light from the light modulating layer, The flat panel display according to claim 1, further comprising: a first polarizer having a first linear polarization plane and a second polarizer having a second linear polarization plane different by the predetermined angle. 4. The phosphor emits white light, and the light modulator receives light from the light source element, and sets a first linear polarization plane or a first linear polarization plane with respect to all color components. A first polarization filter having a second linear polarization plane having a different angle; a first polarization filter that receives light from the first polarizer and rotates the polarization plane of the incident light by the predetermined angle according to data to be displayed; A light modulating layer, light from the first light modulator being incident thereon, having a first linear polarization plane for some color components, and a second linear polarization plane for the remaining color components. A second light modulation layer that receives light from the second polarization filter and rotates a polarization plane of the incident light by a predetermined angle according to data to be displayed; and the second light modulation. Light from the vessel is incident and the first linear polarization plane for some color components The flat panel display device according to claim 1, further comprising: a third polarization filter having a second linear polarization plane for the remaining color components. 5. The flat panel display according to claim 2, wherein the predetermined angle is 90 °. 6. The second polarization filter has a horizontal polarization plane for the blue component, has a vertical polarization plane for the red and green components, and the third polarization filter has a horizontal polarization plane for the red component. 5. The flat panel display device according to claim 4, wherein the display device has a horizontal polarization plane and a vertical polarization plane for blue and green components. 7. The flat panel display according to claim 2, wherein the light modulation layer is made of liquid crystal. 8. The light modulation layer is formed of a PLZT (Lead Lanthan).
um Zirconate Titanate), the flat panel display device according to any one of claims 2, 3 and 4. 9. The light modulation layer is a TFT type or a TFD.
5. The flat panel display device according to claim 2, wherein the flat panel display device is driven by active matrix driving means using a switching element of a type. 10. The flat panel display device according to claim 2, wherein said light modulation layer is driven by a simple matrix driving means. 11. The light source device according to claim 1, wherein each of the light source devices includes a plurality of field emission cold cathodes.
4. The flat panel display device according to 1. 12. The flat panel display device according to claim 1, further comprising: means for driving the light source and the light modulator in conjunction with each other. 13. The flat panel display according to claim 12, wherein the driving unit drives the light source and the light modulator for each of the light source elements. 14. The flat panel display according to claim 12, wherein the driving unit drives the light source and the light modulator for each column of the light source elements.