JPH0689075A - Display device and method of manufacturing fluorescent screen used therefor - Google Patents

Abstract

(57) [Abstract] [Purpose] To realize a large-screen display with high display quality, high brightness, and low power consumption. [Structure] R, G, B visible light emission fluorescent light disposed on a fluorescent screen 2 by a luminous flux of ultraviolet excitation light emitted from cathode ray tubes 51 to 53 of an ultraviolet laser surface light source having an optical resonator on a fluorescent surface. Exciting body dots. Further, a light shielding plate 50 having a plurality of ultraviolet light transmitting portions provided on its optical path is arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and is particularly relevant to application to a display field such as a projection type image display device.

[0002]

2. Description of the Related Art Currently, the CRT is most often used as a display with high display quality. However, a large screen, especially a C with a size of 40 inches or more
The RT has problems that it is deep and heavy, and it is difficult to obtain high brightness. In addition, there is also a problem that the cost is dramatically higher than that of a small-to-medium-sized CRT because of a low yield in manufacturing a CRT.

In recent years, in order to solve these problems, CRTs have been proposed.
Various methods have been proposed as high-definition large-screen displays, which are used in place of, for example, plasma displays, EL displays, liquid crystal displays, and color flat panels (S.I.D. 1985 digest No. 185-186).
Page (announced in SID '85 Digest 185p-186p, Apr.1985) and the like, flat panel displays such as CRT projection type displays and liquid crystal projection type displays are being studied.

[0004]

However, the conventional large-screen display systems of the flat panel display and the projection type display have the following problems, respectively.

(1) Problems of flat panel display ○ Plasma display has low efficiency and large power consumption ○ EL display has not yet obtained high-efficiency phosphors, especially red and blue, which are necessary for high brightness full colorization. ○ Liquid crystal displays are high in cost due to problems such as signal delay due to wiring resistance and parasitic capacitance due to the increase in area, and complicated processes and reduced yields. ○ Color flat panels display quality due to their complicated structure. There are problems such as deterioration of temperature, deterioration over time, weight increase, and cost increase. That is, it is extremely difficult to realize a high-brightness large-screen flat panel display with low cost and low power consumption.

(2) Problems of projection type display ○ CRT projection type display is difficult to obtain high brightness because of low light condensing efficiency of lens system. ○ Liquid crystal projection type display has aperture ratio and polarizing plate transmittance of liquid crystal panel. Or because the lens system has a low light collection rate, it is necessary to use a high-output backlight to obtain high brightness.
There is a problem that the light resistance and power consumption of the polarizing plate and liquid crystal are high.

Further, these projection-type displays have C
Although it is relatively easy to increase the screen size compared to RTs and flat panel displays, unlike them it is not a so-called direct-view type in which the screen itself emits light, and the light from the light source is projected from the front of the screen or from the back. It is a device to watch the image. Therefore, the display quality such as contrast is inferior to that of the direct-view display. In addition, a lenticular lens is provided on the screen to improve the brightness in the front direction. This, on the other hand, reduces the brightness when viewing from an angle and narrows the viewing angle.

The present invention is lightweight, compact and low cost,
An object of the present invention is to provide a display device which can realize a large-screen display with low power consumption and high display quality, and a method for manufacturing a fluorescent screen used in this display device.

[0009]

DISCLOSURE OF THE INVENTION The present invention is directed to an ultraviolet light source that emits ultraviolet light in a plane, a projection lens arranged in the passage direction of the ultraviolet light emitted from this ultraviolet light source, and an ultraviolet light that has passed through this projection lens is irradiated. The above problem is solved by a display device including a phosphor screen having a phosphor layer containing a visible light emitting phosphor that emits visible light.

Further, a preferred embodiment of the display device of the present invention is that an ultraviolet light source that emits ultraviolet light in a planar shape, a projection lens arranged in the passing direction of the ultraviolet light emitted from this ultraviolet light source, and an ultraviolet light that has passed through this projection lens are A fluorescent screen provided with a phosphor layer containing a visible light-emitting phosphor that emits visible light upon irradiation, and light having a portion through which the ultraviolet light passing through the projection lens passes between the projection lens and the fluorescent screen. A display device having a shielding plate, as a method of manufacturing a fluorescent screen of the preferred display device of the present invention, the ultraviolet rays emitted from the ultraviolet source through the projection lens,
A pattern exposure light source is installed at a position corresponding to the irradiation area on the fluorescent screen, and the light shielding plate is used as a mask, and the screen is coated with a negative resist containing a visible light emitting phosphor. It is a method for manufacturing a fluorescent screen, which includes a step of developing a negative resist and forming a pattern of a visible light emitting phosphor on the screen.

[0011]

The display device of the present invention mainly comprises a planar ultraviolet light source, a projection lens, and a fluorescent screen. The ultraviolet light emitted from the ultraviolet source is magnified by the projection lens,
Visible light is emitted by exciting the visible light-emitting phosphor of the fluorescent screen.

In the display device of the present invention, the visible light-emitting phosphor contained in the fluorescent screen is excited by the ultraviolet light emitted from the planar ultraviolet light source through the projection lens, and emits the desired visible light to produce the screen. It is a direct view type displayed on the top.

That is, in the display device of the present invention, the ultraviolet light emitted from the planar ultraviolet source is directly magnified by the projection lens and is directly converted from the ultraviolet light into the visible light by the visible light emitting phosphor contained in the fluorescent screen. The planar ultraviolet light source referred to in the present invention is an ultraviolet light emitting cathode ray tube in which the area for scanning the ultraviolet light emitting phosphor is planar, or the ultraviolet light emitting area is configured by arranging each pixel in a planar shape. It is any one of electroluminescent devices.

If a light shielding plate having a portion that transmits ultraviolet light is provided between the projection lens and the fluorescent screen of the display device of the present invention, the ultraviolet light is emitted from the ultraviolet source and the ultraviolet light is transmitted through the projection lens. It is possible to irradiate the visible light-emitting phosphor contained in the fluorescent screen as excitation light with good control. That is, the ultraviolet light emitted from the ultraviolet source is expanded by the projection lens after being converted into a parallel light flux. A luminous flux of ultraviolet light passes through an ultraviolet light transmitting portion provided on a light shielding plate disposed at a predetermined distance from the fluorescent screen surface, and only the transmitted light is a visible light emitting phosphor corresponding to a predetermined position. And emits fluorescence. The ultraviolet light transmitting portion of the light shielding plate is installed at a relative position such that the light flux of the ultraviolet light from the ultraviolet light source that has passed through the projection lens and the ultraviolet light transmitting portion is irradiated only on a predetermined visible light emitting phosphor. Therefore, the specific luminous flux from the ultraviolet source always excites the specific visible light-emitting phosphor corresponding to the luminous flux.

[0015]

The ultraviolet source of the display device of the present invention is a cathode ray tube equipped with an ultraviolet light emitting phosphor that emits ultraviolet light when excited by an electron beam,
Alternatively, any electroluminescent device including an ultraviolet fluorescent substance that emits ultraviolet rays by electroluminescence can be applied.

According to the constitution of the display device of the present invention, the ultraviolet light emitted from the planar ultraviolet light source is directly expanded on the fluorescent screen to directly display the light emission image, that is, the image information by the ultraviolet light is visualized as a visible image. It is, so to speak, an indirect direct view type. For this reason,
The display device of the present invention is a conventional C
Compared to RT, of course, more than the conventional projection type,
It can be lightweight and compact. Further, it is possible to provide a large-screen display device that is lower in cost than a flat panel display.

The operation when the ultraviolet ray source of the present invention is a cathode ray tube will be described. When the cathode ray tube is operated, the electron beam emitted from the electron gun excites the ultraviolet light emitting phosphor and emits ultraviolet light to the outside of the face plate. The ultraviolet light thus generated is used as excitation light for the visible light-emitting phosphor, and after being converted into a parallel light flux by a projection lens arranged in front of the cathode ray tube, it is expanded and irradiated on a fluorescent screen equipped with the visible light-emitting phosphor arranged in front. It On the fluorescent screen, a fluorescent layer containing a single or multiple types of visible light-emitting phosphors is arranged,
A desired visible light-emitting phosphor is excited through a projection lens to emit visible light of a predetermined color. Therefore, a monochrome or full-color image is displayed on the fluorescent screen by inputting a predetermined image signal to the cathode ray tube.

That is, according to the present invention, it is possible to enlarge the screen at low cost in terms of expanding and projecting the excitation light from the cathode ray tube. In addition, the display quality is high because the screen itself is a direct-view type in which excitation light emits light. That is, according to the present invention, a lightweight, compact, low-cost, high-quality large-screen display can be realized.

In particular, the ultraviolet ray source of the present invention is a cathode ray tube, and an electron beam is applied to a fluorescent surface formed of an optical resonator composed of a pair of reflecting mirrors provided above and below a light emitting layer so as to sandwich it. Then, the light emitting layer is excited to emit ultraviolet light. This light is repeatedly reflected between the pair of reflecting mirrors to cause stimulated emission of ultraviolet light in the light emitting layer. It is preferable that the power of the electron beam is equal to or higher than a certain threshold because laser oscillation occurs. The threshold value can be determined by an optical resonator, an ultraviolet phosphor material, or the like.

The laser light passes through the semitransparent reflecting mirror and is emitted to the outside. Laser light is emitted in a direction perpendicular to the reflecting mirror with a narrow emission angle which is mainly determined by the emission wavelength and the area of the light emitting portion. Since the emission angle of the laser light is narrow, the light is efficiently applied to the fluorescent screen through the lens system.
The visible light-emitting phosphor of the fluorescent screen is excited by this ultraviolet laser light and emits spontaneous emission light of a predetermined color in the visible region. That is, the present invention is lightweight, compact, low cost,
It is possible to realize a high-quality, large-screen display with high brightness and low power consumption.

The operation when the ultraviolet light source of the present invention is an electroluminescent device will be described. When a predetermined AC electric field is applied between the pair of electrodes of the electroluminescent device, ultraviolet light is emitted due to the action of electroluminescence in the ultraviolet light emitting layer. These ultraviolet excitation lights pass through a transparent or semitransparent electrode and are emitted to the outside of the electroluminescent device. The ultraviolet light thus generated is used as excitation light for the visible light-emitting phosphor, is converted into a parallel light flux by a projection lens arranged on the front surface of the electroluminescent element, is expanded, and is irradiated on the fluorescent screen arranged on the front surface. A fluorescent layer containing one or more kinds of visible light emitting phosphors is disposed on the fluorescent screen, and a desired visible light emitting phosphor is excited through a projection lens to emit visible light of a predetermined color. Therefore,
By inputting a predetermined image signal to the thin film electroluminescent device, a monochrome or full-color image is displayed on the fluorescent screen.

Ultraviolet light emitting phosphors applicable to the present invention include diamond and silicon carbide, such as GaN and Al.
III-V group compound semiconductors such as N and BN, for example, ZnO and Z
IIb-VI group compound semiconductors such as nSe, ZnS, and CdS,
For example, IIa-VI group compound semiconductors such as MgS, CaS, SrS, and BaS, chalcopyrite compounds such as CuAlS ₂ , manganese chalcogenide compounds such as MnTe, MnSe, and MnS, or multicomponent compounds containing these or, if necessary, A material obtained by adding a light-emitting donor impurity or an acceptor impurity to these materials may be used. In particular, it is preferable to add a donor impurity or an acceptor impurity because emission efficiency is improved.

Further, the ultraviolet light emitting phosphor applicable to the present invention is, for example, a phosphate phosphor such as Ca ₃ (PO ₄ ) ₂ : Tl ⁺ ,
For example, BaSi ₂ O ₅ : Pb ²⁺ , (Ba, Sr, Mg) ₃
Si ₂ O ₇ : Pb ²⁺ , Ca ₂ MgSi ₂ O ₇ : Ce ³⁺ , Zn ₂
SiO _4: silicate phosphor such as Ti, for example, SrB ₄ O
₇ F: so-called emission center ion-containing phosphor of phosphor such as Eu ²⁺ , yttrium oxide compound, tungsten oxide compound, aluminum oxide compound, rare earth oxide, IIa-
VII2 compounds, IIb-VII2 compounds, alkali halides and the like are also included.

Among such ultraviolet light emitting phosphors, it is preferable that the luminescent center impurity is a lanthanoid ion or an actinide ion having an incomplete f-electron shell because the luminous efficiency becomes high or laser oscillation easily occurs. .

Particularly, the gadolinium ion is preferable as the emission center impurity. That is, in the energy level of the gadolinium ion, the ground level ( ⁸ S _7/2 ) and the first excitation level ( ⁶
The electric dipole transition between P _7/2 ) is originally a ff transition which is forbidden like the other lanthanoid ions, but is allowed under the influence of the crystal field in the crystal matrix. Also ⁸ S _7/2
The energy gap between and ⁶ P _7/2 corresponds to the wavelength in the ultraviolet region. Moreover, the _host material is transparent or semitransparent to the fluorescence associated with the transition of ⁶ P _7/2 → ⁸ S _7/2 . Therefore, when gadolinium ions are used as the emission center of the phosphor material of a cathode ray tube or a thin film electroluminescent device, the fluorescence of the ultraviolet region accompanying the transition of ⁶ P _7/2 → ⁸ S _7/2 of gadolinium ions in the matrix is efficiently obtained. Can be issued. Therefore, a laser of ultraviolet light of about 300 nm can be oscillated.

As the emission center impurity, not only those having an incomplete f-electron shell but also transition metal ions having an incomplete d-electron shell can be applied.

The bandgap of these ultraviolet-emitting phosphors at room temperature is preferably 3.1 eV or more, because ultraviolet rays of 400 nm or less can be emitted.

Since the display device of the present invention excites the visible light-emitting phosphor with ultraviolet rays, it is preferable to install an ultraviolet ray cut filter on the side of the fluorescent layer of the fluorescent screen opposite to the projection lens, because leakage of ultraviolet rays can be prevented. Further, it is preferable to install an ultraviolet light reflecting mirror on the surface of the phosphor screen opposite to the projection lens of the phosphor layer, because it can reflect the ultraviolet rays emitted from the phosphor screen to the outside and re-excite the visible light-emitting phosphor to improve the luminous efficiency. The ultraviolet cut filter and the ultraviolet light reflecting mirror may be installed at the same time. In this case, it goes without saying that the ultraviolet light cut filter is installed outside the ultraviolet light reflecting mirror.

Further, when a visible light reflector is installed between the fluorescent screen and the projection lens of the display device of the present invention, visible light emitted from the visible light-emitting phosphor can be reflected back to the inner projection lens side, This is preferable because the display brightness can be improved.

The display device of the present invention is also compatible with a plurality of colors. In order to support a plurality of colors, a plurality of ultraviolet light sources corresponding to the colors that emit light, a projection lens corresponding to a plurality of ultraviolet light sources, and a fluorescent screen having a plurality of visible light emitting phosphors may be provided. Especially when displaying in a plurality of colors, if a light shielding plate having a portion that transmits ultraviolet light is provided between the projection lens and the fluorescent screen, the ultraviolet light incident from the ultraviolet source through the projection lens can be given a predetermined amount. It is preferable because the visible light-emitting phosphor contained in the fluorescent screen can be irradiated and excited with good control. That is, the ultraviolet light generated from a plurality of ultraviolet light sources is expanded after being made into a parallel light flux by the projection lens arranged in front of them. The light flux of the ultraviolet light that has passed through the projection lens passes through the ultraviolet light transmitting portion provided on the light shielding plate arranged at a predetermined distance from the fluorescent screen surface, and only the transmitted light is the respective ultraviolet light source. The phosphor dots of the emission color corresponding to are emitted to emit fluorescence. A light beam emitted from a predetermined light emitting point of each planar ultraviolet light source reaches each ultraviolet light transmitting portion, and even after passing through the ultraviolet light transmitting portion, the optical path goes straight on and reaches the fluorescent screen surface. Since the sources are installed at different positions, the incident direction and angle of the light flux that reaches a certain ultraviolet light transmitting portion are different. Therefore, the position where each light flux reaches each visible phosphor of the fluorescent screen also differs. Since the ultraviolet light transmitting portion of the light shielding plate is arranged at a relative position such that the luminous flux of the ultraviolet light transmitted from each of the ultraviolet light sources is irradiated to only one predetermined type of phosphor dot, respectively. The luminous flux from the ultraviolet light source excites the visible light emitting phosphor dots of a certain emission color. That is, it is possible to provide a display device of a plurality of colors with no color shift.

The fluorescent screen of the display device provided with the light shielding plate of the present invention can be manufactured as follows. A screen serving as a fluorescent screen, a projection lens, and a light shielding plate are installed at the position of the display device of the present invention, and a position corresponding to an irradiation area irradiated from the ultraviolet source of the display device of the present invention onto the fluorescent screen through the projection lens. A pattern exposure apparatus is used in which a planar pattern exposure light source is installed in the place where the irradiation is performed. Using the pattern exposure apparatus having such a configuration, the light shielding plate itself provided with a plurality of ultraviolet light transmitting portions is used as an exposure mask, and the pattern is applied to the screen coated with the negative resist containing the visible light emitting phosphor. -Exposure from a light source, exposing the negative resist to light, and developing to form a pattern of visible light-emitting phosphor on the screen.

Specifically, a negative resist mixed with a visible light-emitting phosphor that emits fluorescence of a desired wavelength is applied to the screen. Next, the exposure light source is made to emit light. The light emitted from the exposure light source passes through the projection lens and is expanded after being collimated.
This light beam illuminates the light shielding plate, transmits the ultraviolet light transmitting portion of the light shielding plate, and irradiates the screen with a shape similar to the ultraviolet light transmitting portion. The light flux irradiated on the screen sensitizes the negative resist containing the visible light emitting phosphor, and fixes the pattern of the visible light emitting phosphor on the screen. By washing the screen after the exposure, the negative resist other than the irradiated portion is removed together with the visible light emitting phosphor, and the fluorescent screen can be manufactured.
The position where the pattern is irradiated on the screen is determined by the incident direction of the light beam, the incident angle, and the distance between the fluorescent screen and the light shielding plate.

The method of manufacturing a fluorescent screen of the present invention is particularly effective in displaying a plurality of colors. The difference in the manufacturing method of the fluorescent screen between the case of displaying in multiple colors and the case of displaying in single color is that the number of exposure light sources is the same as the number of display colors,
The only difference is that the type of visible light-emitting phosphor that emits fluorescence corresponding to the display color is required, and the rest can be basically manufactured in the same manner.

First, a negative resist containing a mixture of visible light emitting phosphor powder A of a predetermined light emitting color is applied on a phosphor screen. Next, the exposure light source a equivalent to the ultraviolet light source corresponding to the visible light emitting phosphor A is caused to emit light. The light emitted from the exposure light source a passes through the projection lens and is converted into a parallel light flux, and then expanded. This light beam illuminates the light shielding plate, transmits the ultraviolet light transmitting portion of the light shielding plate, and irradiates the screen with a shape similar to the ultraviolet light transmitting portion. The luminous flux irradiated on the screen is a visible light-emitting phosphor A.
The negative resist containing the is exposed to light to fix the pattern α of the visible light emitting phosphor A on the screen. The position of the pattern α of the visible light-emitting phosphor A is determined by the incident direction of the light flux, the incident angle, and the distance between the fluorescent screen surface and the ultraviolet light transmitting portion, as in the case of the above-described single color. After the exposure, the screen is washed so that the negative resist other than the irradiation part is exposed to the visible light emitting phosphor A.
Along with this, the pattern α of the visible light emitting phosphor A can be produced.

Next, a photosensitive negative resist in which the visible light emitting phosphor A and the visible light emitting phosphor powder B having a different emission color are mixed is coated on the fluorescent screen. An exposure light source b equivalent to an ultraviolet ray source corresponding to the visible light emitting phosphor B is caused to emit light. As a result, as in the case of the visible light emitting phosphor A, the exposure light source b
The light emitted from the light is expanded through a projection lens after being converted into a parallel light flux, which is then irradiated onto the light shielding plate and transmitted through the ultraviolet light transmitting portion of the light shielding plate, and then is irradiated onto the screen in a shape similar to the ultraviolet light transmitting portion. Then, the irradiated light flux sensitizes the negative resist containing the visible light emitting phosphor b, fixes the pattern of the visible light emitting phosphor B on the screen, and cleans the screen so that the negative resist other than the irradiated portion is visible. A fluorescent screen having visible light emitting phosphors A and B, which is removed together with the light emitting phosphor B, can be formed.

Since the exposure light source a and the exposure light source b are disposed at a predetermined distance, the incident direction of the light flux from each exposure light source entering the same ultraviolet light transmitting portion of the light shield plate,
The angle of incidence is different. That is, the position where the light flux from the exposure light source b is projected on the fluorescent screen is different from that from the exposure light source a. Therefore, the position of the pattern β of the visible light emitting phosphor B formed by the exposure with the light flux from the exposure light source b is different from the position of the pattern α of the visible light emitting phosphor A. The above process can be performed for each exposure light source corresponding to the display color to provide a pattern of visible light emitting phosphors of each emission color.

The pattern of the visible light emitting phosphor thus formed on the screen is the same optical path of the ultraviolet light as in the display device of the present invention, and the visible light is emitted by the ultraviolet light generated from the ultraviolet light source through the projection lens. There is an effect that the efficiency of exciting the phosphor is high. It is preferable to use the ultraviolet light source of the present invention as the pattern exposure light source because the structure of the display device itself becomes a pattern exposure device.

Particularly, in the case of a fluorescent screen for displaying a plurality of colors, it is preferable to form a so-called black matrix layer in which means for surrounding the boundary of each visible light emitting phosphor pattern with a black streak is formed because the contrast is improved.

The fluorescent screen provided with this black matrix layer is prepared by mixing a black colorant such as carbon powder with a photosensitive positive resist to prepare a required number of visible light emitting phosphor patterns. Apply to.
All exposure light sources are driven on a fluorescent screen coated with a positive resist containing a black colorant to irradiate all visible light emitting phosphor pattern positions with ultraviolet rays. Then, the phosphor screen is washed to remove the positive resist containing the black colorant, which was covered on each phosphor dot. By the above work, the black matrix layer can be formed in a place other than each visible light emitting phosphor pattern.

Next, the present invention will be described in more detail with reference to specific examples of the display device of the present invention.

(Embodiment 1) FIG. 1 is a sectional view of an embodiment of the display device of the present invention. A fluorescent screen 2 is provided on the front surface of the container 1, and a cathode ray tube 3 is provided at a predetermined position inside the container 1. Further, the projection lens 4 and the reflecting mirrors 5 and 6 are provided at positions where the light emitted from the cathode ray tube 3 to the front surface is enlarged and projected on the fluorescent screen 2.

FIG. 2 shows a sectional view of the cathode ray tube 3 used in this embodiment. The cathode ray tube 3 is mainly composed of an ultraviolet light emitting phosphor surface 11
Other than that, the structure is similar to that of a normal CRT. An electron gun 16 including a cathode 14 and an electron lens 15 is provided on a neck portion 13 of a glass bulb 12 whose inside is kept in a high vacuum. An ultraviolet light emitting phosphor surface 11 is provided on the inner surface of the face plate 17, and the surface of the glass bulb 12 is electrically connected to an inner conductive film 18 that has been subjected to a conductive treatment on a predetermined area of the inner surface of the glass bulb 12, and a predetermined area is externally provided via an anode button 19. A voltage can be applied. A deflection yoke 20 is provided at the neck portion 13. The glass bulb 12 may partially use metal or the like, if necessary.

The thickness of the ultraviolet light emitting phosphor surface 11 is 100 n.
The ultraviolet light emitting phosphor layer 21 having a thickness of about m to 100 μm and the total film thickness provided on the face plate side thereof is 100 nm to 1
It is composed of a multilayer film reflecting mirror 22 having a thickness of about 00 μm and a metal reflecting mirror 23 having a film thickness of several tens to several hundreds nm, which is also provided on the electron gun side. The metal reflecting mirror 23 is electrically connected to the internal conductive film 18.

As one example, a single crystal film of zinc sulfide is used for the ultraviolet fluorescent layer 21, and SiO 2 is used for the multilayer film reflecting mirror 22.
It will be described the case of using ₂ thin film and multilayer film TiO ₂ made of thin film composite membranes have been several cycles to several tens period stacking. The thickness of each dielectric film is 1/4 of the emission wavelength in them.
It was set to a value close to an odd multiple of. Further, a vapor deposition film of aluminum was used for the metal reflecting mirror 23. Face plate 1
A glass having a composition that well transmits the ultraviolet light emitted from the phosphor screen 11 was used for 7.

FIG. 3 shows a perspective view of a fluorescent screen used in a display device, taking a color display device as an embodiment of the display device of the present invention. The size of the fluorescent screen of this embodiment is a large screen with a diagonal size of 40 inches or more. The fluorescent screen includes a screen substrate 31, a band-shaped visible light emitting phosphor stripe 32 which is periodically formed on the inner surface side of the container, and a black matrix 33 which is formed in the space between the visible light emitting phosphor stripes 32. It is composed of.

The visible light emitting phosphor stripe 32 is, for example, a red light emitting phosphor (R), a green light emitting phosphor (G), a blue light emitting phosphor (B), a red light emitting phosphor (R), ... It is arranged in. For the screen base 31, a resin plate or a glass plate that is transparent to these visible lights can be applied,
In this example, glass was used.

Zn _0.2 Cd _0.8 S: Ag and Zn are provided on the red, green and blue visible light emitting phosphor stripes 32, respectively.
_0.6 Cd _0.4 S: Ag, (Sr, Ca) ₁₀ (PO ₄ ) ₆ Cl
₂ : A visible light emitting phosphor powder of Eu was used. Note that the visible light-emitting phosphor may be any phosphor that emits red, green, and blue, and the material is not particularly selected.

Carbon powder was used as the black colorant of the black matrix 33. This may also be made of another light-resistant black material or the like.

The operation of this embodiment shown in FIGS. 1 to 3 will be described below. A positive voltage of about several kV to 100 kV is applied to the phosphor screen 11 with respect to the potential of the cathode 14, and the electron gun 16
The electron beam ejected from is focused on a predetermined beam diameter, accelerated, and impinged on the phosphor screen 11. Electron beam
It is deflected by the deflection yoke 20 and scanned on the phosphor screen at a predetermined cycle. A predetermined image signal is transmitted to the electron gun 16 and the deflection yoke 20.
And enter.

The electron beam is transmitted through the metal reflecting mirror 23 and is injected into the ultraviolet fluorescent layer 21 to excite the zinc sulfide matrix. Zinc sulfide emits ultraviolet light having a wavelength of, for example, about 340 nm, which corresponds to transition between excitons and band gaps.

For the ultraviolet light emitting phosphor layer 21, it is preferable to use a high quality single crystal film having few non-emission centers such as lattice defects in order to efficiently emit light.

The multilayer reflecting mirror 22 and the metal reflecting mirror 23, which are provided on both sides of the ultraviolet light emitting phosphor layer 21 so as to face each other with the ultraviolet light emitting phosphor layer 21 interposed therebetween, serve to emit light from the ultraviolet light emitting phosphor layer 21. In contrast, it has a high reflectance and acts as an optical resonator for light emission. That is, when emitting light, the reflecting mirrors 22 and 2
Reflection is repeated between 3 and 3, and the ultraviolet emission phosphor layer 21 causes stimulated emission of substantially the same wavelength. Here, laser oscillation occurs when the power density of the electron beam exceeds a certain threshold value. The laser light passes through the semitransparent multilayer-film reflective mirror 22 and is emitted to the outside. The laser light is emitted with a narrow divergence angle mainly determined by the emission wavelength and the area of the light emitting portion, with good parallelism in the vertical direction to the reflecting mirror. The laser light passes through the face plate 17 and is emitted in front of the cathode ray tube 3.

The thickness of the ultraviolet light emitting phosphor layer 21 is preferably set so that the energy conversion efficiency from the input to the laser light output is maximized under a predetermined driving condition. Specifically, a film thickness that allows the energy of the electron beam to be absorbed by the ultraviolet light emitting phosphor layer 21 as efficiently as possible with respect to the penetration depth of the electron beam, and the loss due to reflection and absorption in the optical resonator is minimized. Set to. Metal reflector 2
It is desirable that the film thickness of 3 is set to an optimum value in which the reflectance of the ultraviolet fluorescent layer 21 for light emission is sufficiently high and the electron beam can be transmitted as much as possible. In this example, the reflectance of the metal reflecting mirror 23 for light emission was about 80% or more.
Moreover, the number of laminated layers of the multilayer-film reflective mirror 22 was set so that the reflectance for light emission was about 90% or more. In order to reduce the threshold power density of laser oscillation, it is desirable to use a high quality single crystal film with low loss for the ultraviolet light emitting phosphor layer 21 and to maximize the reflectance of both reflecting mirrors.

The laser light emitted from the cathode ray tube 3 is efficiently enlarged and projected on the fluorescent screen 2 via the projection lens 4, the reflecting mirror 5 and the reflecting mirror 6 as shown in FIG.

The ultraviolet laser light projected on the fluorescent screen 2 excites the visible light emitting phosphors of the visible light emitting phosphor stripe 32, and efficiently emits the visible light of each color. These visible lights pass through the screen substrate 31,
It is radiated diffusely to the front of the screen.

The layer thickness of the visible light emitting phosphor powder of the phosphor stripe 32 is set to an optimum thickness capable of efficiently absorbing the ultraviolet laser light and radiating it to the front surface efficiently.

The ultraviolet laser light scans the fluorescent screen 2 and sequentially excites the red, green and blue visible light emitting phosphor stripes. In the cathode ray tube 3, R,
The image signal is input so that an ultraviolet laser beam having an output corresponding to the G and B luminance signals is emitted. That is, the ultraviolet laser light is synchronously scanned so that, for example, when the laser light having an optical output corresponding to the R signal is emitted, it is just irradiated on the red phosphor.

The area where the electron beam of the cathode ray tube 3 scans the phosphor screen 11, the spot diameter of the electron beam, and the incident power are set so that the brightness, resolution, etc. required for the display image on the fluorescent screen 2 are satisfied.

When the display device of the present embodiment as described above was driven under predetermined conditions, the fluorescent screen 2 itself emitted light, so that high display quality such as contrast was obtained.

Further, since the divergence angle of the laser light emitted from the cathode ray tube 3 is narrow, the projection lens 4 can collect and project the light from the cathode ray tube 3 at a high light collecting rate of about 80% or more. That is, in a conventional projection tube using a fluorescent screen, the emitted light is spontaneous emission and is diffusely emitted from the fluorescent screen. Therefore, even if an optimal projection lens is used to collect light, the light collection rate is about 10%. Compared with the low value, the display device of the present invention has a much higher light collection rate. That is, even if the loss at the time of energy conversion from ultraviolet light to visible light on the fluorescent screen 2 is subtracted, it is possible to more efficiently display with high brightness. Therefore, in the conventional projection display, sufficiently high brightness can be obtained without providing the lenticular lens provided on the screen in order to increase the brightness in the front direction of the screen. Thus, unlike the conventional projection display, the display light of the display device of the present invention is diffusely emitted from the screen to the front surface thereof, so that a display device having a wide viewing angle can be realized.

As described above, according to the invention shown in this embodiment, it is possible to realize a large-screen display which is lightweight, compact, low in cost, particularly high in image quality, high in brightness and low in power consumption.

Next, a method of manufacturing the phosphor screen 11 of the display device of this embodiment will be described below. First, GaAs single crystal substrate (1
(00) On the surface, a ZnS single crystal epitaxial film was grown to a predetermined thickness using the molecular beam epitaxial growth method to form the ultraviolet light emitting phosphor layer 21. High-purity ZnS polycrystalline grains were used as the evaporation source. A film having a sufficient crystallinity was obtained at a predetermined film thickness or more.

Next, an SiO ₂ layer and a TiO ₂ layer were alternately deposited thereon by an electron beam evaporation method so that each had a predetermined film thickness, and the multilayer film reflecting mirror 22 was completed. .

The ultraviolet fluorescent layer 21 and the multilayer reflecting mirror 2 are provided on the surface.
2 is formed on the GaAs substrate by the face plate 17
Was adhered so that the multilayer film reflecting mirror 22 side was in contact. For example, a polyimide resin transparent to ultraviolet light was uniformly and thinly applied on a smooth face plate, and the substrate was attached and then heated to adhere.

Next, these were immersed in an etching solution for etching only the GaAs substrate for a predetermined time to remove the GaAs substrate. As the etching liquid, for example, a mixed liquid of hydrogen peroxide water and ammonia water was used. On the surface where the GaAs substrate is removed and the ultraviolet fluorescent layer 21 is exposed, aluminum is vapor-deposited to a predetermined thickness by using a vacuum vapor deposition method, and the metal reflector 2
3 was produced. The phosphor screen 11 was completed as described above.

A printing method was used to form the phosphor stripe 32. That is, a phosphor powder mixed with a binder that does not easily absorb the ultraviolet light from the cathode ray was printed on the screen base 31 for each color. In addition to this, for example, a heat-resistant material such as glass may be used for the screen base 31, and the fluorescent screen 2 may be heated to remove the binder.

Another embodiment of the method for manufacturing the ultraviolet light emitting phosphor surface 11 is shown below. Bond the ZnS single crystal substrate to the pedestal,
After polishing the surface so that it has a predetermined thickness, a multilayer-film reflective mirror 22 composed of a SiO ₂ layer and a TiO ₂ layer is formed on the surface.
Was completed by the film forming method similar to the above-mentioned embodiment. Next, this was adhered to the face plate 17 so that the multilayer film reflection mirror 22 side was in contact. Next, the pedestal was peeled from the ZnS single crystal substrate. On the surface where the ultraviolet light emitting phosphor layer 21 is exposed, aluminum is vapor-deposited to a predetermined thickness to form a metal reflector 23
Was produced.

In this embodiment, the ultraviolet light emitting phosphor layer 2 is used.
Although ZnS was used as the material of No. 1, any other material may be used as long as it has a bandgap of 3.1 eV or more at room temperature and efficiently emits ultraviolet light when irradiated with an electron beam. Specifically, as the ultraviolet light emitting phosphor layer 21, II, such as diamond, SiC, GaN, AlN, or BN, is used.
Group IV compounds, IIb-VI compounds such as ZnO, IIa-VI compounds such as MgS, CaS, SrS and BaS, chalcopyrite compounds such as CuAlS ₂ and manganese such as MnTe, MnSe and MnS. A chalcogenide compound or a multi-component compound containing at least these may be used. Moreover, you may use what added the luminescent donor property impurity or acceptor property impurity to these materials as needed.

Further, a phosphate phosphor such as Ca ₃ (PO ₄ ) ₂ : Tl ⁺ , or BaSi ₂ O ₅ : Pb ²⁺ , (Ba, S
r, Mg) ₃ Si ₂ O ₇ : Pb ²⁺ , Ca ₂ MgSi ₂ O ₇ : C
A so-called luminescent center ion-containing ultraviolet phosphor such as a silicate phosphor such as e ³⁺ , Zn ₂ SiO ₄ : Ti, or a phosphor such as SrB ₄ O ₇ F: Eu ²⁺ may be used.

Other base materials include yttrium oxide compounds, tungsten oxide compounds, aluminum oxide compounds, rare earth oxides,
Alternatively, a IIa-VII ₂ compound, a IIb-VII ₂ compound, an alkali halide or the like may be used.

In addition, in the emission center ion, incomplete f
Of the lanthanoid or actinide ion having an electron shell or the transition metal ion having an incomplete d electron shell, a predetermined ion that efficiently fluoresces in the ultraviolet region in the base material is adopted. In particular, Gd as the emission center ion
^{When 3+} was used to drive the cathode ray tube 3 using, for example, an ultraviolet light emitting phosphor layer 21 dispersed in a host crystal of ZnF _{2 at} a predetermined concentration, the phosphor screen 11 was excited by an electron beam.
In, it was possible to cause laser oscillation of ultraviolet light having a wavelength of around 310 nm. At that time, other parts such as the multilayer film reflecting mirror were also designed to be optimal for this wavelength. By using this cathode ray tube in the display device, it was possible to realize a high-quality large-screen display having the same function as that of the above-mentioned embodiment.

The method for producing the ultraviolet light emitting phosphor layer 21 was as follows. First, GaAs single crystal substrate (1
A ZnF ₂ : Gd ³⁺ film was grown on the (00) surface using the molecular beam epitaxial growth method. ZnF ₂ grains and GdF ₃ grains were used as evaporation sources. The multilayer-film reflective mirror 22 and the metal reflective mirror 23 were manufactured by the same method as in the above-described embodiment.

In the above embodiment, the multilayer film reflecting mirror 22 is used.
As the dielectric multi-layered film composed of the SiO ₂ layer and the TiO ₂ layer was used as the material, other dielectric materials can be used as long as the materials have different refractive indexes and are transparent or semitransparent to the light emitted from the ultraviolet fluorescent layer. Membrane combinations may also be used. For example, CeO ₂ or the like as the high refractive index film material, CaF ₂ as the low refractive index film material,
LiF, MgF ₂ or the like may be used. A predetermined semiconductor multilayer film may be used as long as the above conditions are satisfied. Alternatively, a multilayer film formed of a dielectric film and a semiconductor film may be used.

Instead of the multilayer film reflecting mirror 22, a semitransparent metal film reflecting mirror made of, for example, an Au thin film having a film thickness of several 10 nm may be used.

In some cases, the multilayer-film reflective mirror 22
Need not be provided. In that case, it is desirable that the reflectance of the laser light at the laser light emission side interface of the ultraviolet fluorescent layer 21 or the interface corresponding thereto is as high as possible.

If necessary, the multilayer reflecting mirror 22 may be used instead of the metal reflecting mirror 23.
At that time, when a material having no conductivity is used for the multilayer film reflecting mirror, it is preferable to provide a conductive layer on the surface thereof.

(Second Embodiment) A second embodiment of the display device of the present invention will be described below. The second embodiment differs from the first embodiment in the configuration of the ultraviolet light emitting phosphor surface 11 and the manufacturing method thereof. FIG. 4 is a sectional view of a cathode ray tube used in the second embodiment. On a transparent substrate 40 made of sapphire single crystal, ZnMnSSe films having different composition ratios were alternately laminated for several cycles to several tens cycles with film thicknesses close to odd multiples of 1/4 of the emission wavelength among them. A semiconductor multilayer film reflecting mirror 41 is formed, and an ultraviolet light emitting phosphor layer 21 made of a ZnSSe single crystal film having a predetermined film thickness is formed thereon.
A rear reflecting mirror 43 composed of a dielectric thin film 42 made of SiO ₂ and a metal thin film 43 made of Al is provided thereon. ZnSS forming the ultraviolet light emitting phosphor layer 21
The composition ratio of e was set so that the band gap was 3.1 eV or more. The composition ratio of the ZnMnSSe mixed crystal forming the semiconductor multilayer film reflecting mirror 41 was set to such a ratio that the band gap thereof was larger than the band gap of the ultraviolet light emitting phosphor layer 21. As another constituent material of the semiconductor multilayer film reflecting mirror 41, for example, a ZnMgSSe mixed crystal thin film or the like may be used.

The operation of this embodiment is similar to that of the first embodiment.
The electron beam emitted from the electron gun 16 is accelerated and strikes the ultraviolet light emitting phosphor surface 11. The electron beam passes through the back reflecting mirror 42 and is injected into the ultraviolet light emitting phosphor layer 21 to excite ZnSSe. ZnSSe emits ultraviolet light of 340 to 400 nm corresponding to the band gap. The semiconductor multilayer film reflection mirror 41 and the back reflection mirror 43 have high reflectance with respect to the light emission of the ultraviolet light emitting phosphor layer 21,
It plays the role of an optical resonator for light emission. That is, the emitted light is repeatedly reflected between the two reflecting mirrors 41 and 43 to cause the ultraviolet light emitting phosphor layer 21 to oscillate at substantially the same wavelength. The laser light passes through the semitransparent semiconductor multilayer film reflecting mirror 41 and the transparent substrate 40 and is emitted in front of the cathode ray tube 3. This laser light sequentially excites the visible light emitting phosphor stripes 32 while scanning the phosphor screen 2. The fluorescent stripes 32 emit R, G, and B visible fluorescence to the front surface.

When the display device of this embodiment was driven under predetermined conditions, high display quality and high brightness were obtained as in the first embodiment.

Next, a method for manufacturing the phosphor screen 11 of this embodiment will be described below. First, a ZnMnSSe thin film having a different composition ratio was alternately grown on a sapphire single crystal substrate by a molecular beam epitaxial growth method so as to have a predetermined film thickness. At that time, their composition ratios were set so that their band gaps were wider than the energy corresponding to the emission wavelength from the ultraviolet fluorescent layer 21 and the difference in refractive index between them was as large as possible. Furthermore, their lattice constants should be as close as possible to the lattice constant of ZnSSe forming the ultraviolet light emitting phosphor layer 21,
It is preferable to set the composition ratio. The ZnMnSSe film could be epitaxially grown as a single crystal on the sapphire substrate under predetermined conditions. These ZnMn
The SSe thin films were alternately laminated in a predetermined cycle to complete the semiconductor multilayer film reflecting mirror 41.

A ZnSSe single crystal epitaxial film having a predetermined film thickness was formed thereon by the same molecular beam epitaxial growth method.

A SiO ₂ film is vapor-deposited thereon using an electron beam vapor deposition method, and then an Al thin film is vapor-deposited thereon to form a back reflector 43.
Was completed.

A sapphire single crystal substrate having an ultraviolet light emitting phosphor surface 11 formed on the surface thereof was adhered to a glass bulb 12 with the ultraviolet light emitting phosphor surface 11 inside, and sealed to complete the cathode ray tube 3.

(Embodiment 3) Next, a third embodiment of the display device of the present invention will be described below. In each of Examples 1 and 2, a cathode ray tube provided with an ultraviolet light emitting phosphor surface of a laser structure having an optical resonator was used, but in this Example, a cathode ray tube having a conventional structure was used. That is, in place of the ultraviolet light emitting phosphor surface 11 in FIG. 2 or 4, an ultraviolet light emitting phosphor powder layer that efficiently emits ultraviolet light by electron beam excitation was used. A metal back layer was provided on it as appropriate.

The ultraviolet light emitting phosphor powder may be, for example, Ca.
₃ (PO ₄ ) ₂ : Tl ⁺ , BaSi ₂ O ₅ : Pb ²⁺ , (Ba,
Sr, Mg) ₃ Si ₂ O ₇ : Pb ²⁺ , Ca ₂ MgSi ₂ O ₇ :
Ce ³⁺ , Zn ₂ SiO ₄ : Ti, SrB ₄ O ₇ F: Eu ^{2+ and the} like can be mentioned. In this example, Ca ₃ (PO ₄ ) ₂ : Tl ⁺ was used. An Al thin film was used for the metal back layer.

The electron beam emitted from the electron gun 16 is accelerated and injected into the ultraviolet light emitting phosphor powder layer. The ultraviolet light emitting phosphor powder layer emits ultraviolet light having a predetermined wavelength. This ultraviolet light is spontaneous emission light and is diffusely emitted in front of the cathode ray tube 3. The light is condensed by a projection lens, converted into a parallel light flux, expanded, and projected onto the fluorescent screen 2 via the reflecting mirrors 5 and 6. This ultraviolet light sequentially excites the phosphor stripes 32 while scanning the phosphor screen 2. The fluorescent stripes 32 emit R, G, and B visible fluorescence to the front surface.

When the display device of the present example was driven under predetermined conditions, a direct-viewing type large screen display was possible. However, the brightness did not reach that of Examples 1 and 2.

(Embodiment 4) Next, the display device of the present invention will be described.
A fourth embodiment will be shown below. In this embodiment, the cathode ray tube
Instead, use matrix-driven thin film EL devices
It was FIG. 5 is a sectional view of one pixel portion of this embodiment. Gala
A transparent conductive film made of ITO with a thickness of about 200 nm on the substrate 44.
Electrolytic film 45 is vapor-deposited, and the thickness is about 300 nm.
Degree BaTa ₂O₆The insulating film 46 made by the rf sputtering method
It is vapor-deposited. On top of that, Gd is used as the emission center.³⁺To
ZnF with a thickness of about 800 nm containing several mol%₂:
GdF_xThe ultraviolet light emitting phosphor layer 47 made of
It is provided by the deposition method, and the thickness of 300n is again provided on it.
BaTa of about m₂O₆Made insulating film 48 and thickness 200n
A counter electrode 49 made of Al and having a size of about m is provided.

When this EL device was driven under predetermined conditions, the ultraviolet light emitting phosphor layer 47 efficiently emitted ultraviolet light in the vicinity of 310 nm. This ultraviolet light was transmitted through the glass substrate 44, condensed by a projection lens arranged in front of the glass substrate 44, converted into a parallel light flux, expanded, and projected onto the fluorescent screen 2 via the reflecting mirrors 5 and 6.

Ultraviolet light sequentially excited the visible light emitting phosphor stripes 32 while scanning the phosphor screen 2. Visible fluorescence of R, G, B was radiated to the front from the visible light emitting phosphor stripe 32.

In all of the above embodiments, the fluorescent screen is irradiated with ultraviolet light from the rear surface to emit light. However, an ultraviolet light source such as a cathode ray tube or a thin film EL element is arranged on the front surface of the fluorescent screen, May excite the phosphor of the fluorescent screen.

(Fifth Embodiment) Next, a fifth embodiment of the display device of the present invention will be described below. FIG. 6 is a sectional view of the display device of this embodiment. The main difference of the configuration of the present embodiment from the above-described embodiments is that the light shielding plate 50 is provided at a predetermined position on the ultraviolet excitation light irradiation side of the fluorescent screen 2.
That is, three cathode ray tubes 51, 52, 53 that emit ultraviolet light corresponding to the respective R, G, B emission colors are provided horizontally.

FIG. 7 shows an enlarged view of the vicinity of the light shielding plate 50 and the screen 2. The light shielding plate 50 is provided with a plurality of ultraviolet light transmitting portions 54 at predetermined intervals. Further, the fluorescent screen 2 is provided with R, G, and B types of visible light emitting phosphor dots 55, 56, and 57, one set for each ultraviolet light transmitting portion 54.

In this embodiment, a glass plate which transmits the ultraviolet light from the cathode ray tube is used as the base material of the light shielding plate 50. On top of that, a black paint that is resistant to ultraviolet light,
The light shielding plate 50 is printed by printing in a place excluding the ultraviolet light transmitting portion 54.
Was completed.

The same phosphor material as that used in Example 1 was used for forming the phosphor dots 55, 56 and 57. The printing method was used in the same manner as in Example 1 to create these.

In order to form a predetermined phosphor dot at an appropriate relative position of the ultraviolet light transmitting portion, a computer is used to prepare the light flux from each cathode ray tube when the light shield plate 50 and the phosphor dot are prepared. The optical path was calculated and the optimum design was performed.

The cathode ray tubes 51, 52 and 53 respectively have R,
An image signal that emits an ultraviolet laser beam having an output corresponding to the G and B luminance signals is input.

The excitation light emitted from each cathode ray tube 51, 52, 53 is magnified by the projection lens arranged in front of them. The luminous flux of the excitation light is transmitted through only the ultraviolet light transmitting portion provided on the light shielding plate, and each of the cathode ray tubes 5
Visible luminescent phosphor dots 55 of luminescent colors corresponding to 1 to 53
It is projected to ~ 57 and emits fluorescence. The light flux emitted from a predetermined light emitting point on the face plate of each cathode ray tube reaches each ultraviolet light transmitting portion of the light shielding plate, and after passing through the ultraviolet light transmitting portion, goes straight along its optical path and reaches the fluorescent screen surface. However, since each cathode ray tube is installed at a different position, the incident direction and angle of each light flux reaching a certain ultraviolet light transmitting portion are different. Therefore, the position where each light flux reaches the fluorescent screen surface also differs. The visible light emitting phosphor dots 55, 56, 57 are
Since the R, G, and B cathode ray tubes 51, 52, and 53 are installed at relative positions so that only the luminous fluxes 58, 59, and 60 of the excitation light are emitted, for example, ultraviolet rays from the R cathode ray tube 51 are used. The luminous flux 58 of the excitation light selectively irradiates only the R light emitting phosphor dots 55, and the G light emitting phosphor dots 56 and B are emitted.
The light emitting phosphor dots 57 are not irradiated.

In the first to fourth embodiments described above, the irradiation position of the luminous flux of the excitation light changes with time due to, for example, the thermal drift, and the blue phosphor stripe is irradiated with the excitation light corresponding to the red signal, for example. There is a possibility of causing a so-called color shift such as being lost, but in the display device of the present embodiment, for example, the excitation light from the R cathode ray tube 51 always irradiates only the R phosphor dot 55, so there is no such concern. That is, according to the present embodiment, it is possible to obtain a fluorescent screen having no further color shift.

When the display device of this example was driven under predetermined conditions, it was of high quality and high brightness as in the above examples.
Furthermore, we were able to realize a large-screen display with no color shift over time.

In the present embodiment, three cathode ray tubes, one for each of R, G, and B, are provided as a radiation source of the excitation light, but a total of three cathode ray tubes are provided.
A plurality of cathode ray tubes, for example, two cathode ray tubes in total, may be provided for each color, that is, a total of six cathode ray tubes.

Further, as the material of the light shielding plate 50, other than the above-mentioned embodiment, for example, a metal plate having holes at predetermined intervals may be used.

Further, although the cathode ray tubes are arranged in one horizontal line in this embodiment, they may be arranged in another arrangement such as a triangular shape if necessary.

Next, a method of manufacturing the fluorescent screen 2 used in the display device of this embodiment will be described. The light shield plate itself or a mask corresponding thereto was placed as an exposure mask at a predetermined position from the fluorescent screen surface. The relative position between the exposure mask and the fluorescent screen is equal to the relative position between the fluorescent screen and the light shielding plate in the display device of this embodiment.

As an exposure light source for the visible light emitting phosphor dots of each color of the fluorescent screen, an ultraviolet light source itself or a light source for irradiating the fluorescent screen with an equivalent light flux was set at a predetermined position together with a predetermined projection lens. That is, the light trace of the light flux from each exposure light source to at least the fluorescent screen through the ultraviolet light transmitting portion of the exposure mask,
The position of the exposure light source was determined so as to pass through the same relative position as the light trace in the completed display device.

First, a photosensitive negative resist in which the powder R of the visible light emitting phosphor for R was mixed was applied on the fluorescent screen. Next, the exposure light source r for R was driven to emit ultraviolet light from the exposure light source r. The ultraviolet light is expanded by the projection lens, the light flux is irradiated to the ultraviolet light transmitting portion provided in the light shielding plate, only the region of the ultraviolet light transmitting portion is transmitted and the fluorescent screen surface has the same shape as the ultraviolet light transmitting portion. Is projected as a luminous flux of. The photosensitive negative resist was exposed only at the place where the ultraviolet light was projected, and the visible light emitting phosphor dots r having the same shape as the ultraviolet light transmitting portion were fixed on the fluorescent screen. After that, the fluorescent screen was washed to remove the visible light emitting phosphor powder R attached to other places.

Next, a photosensitive negative resist in which the powder G of the visible light emitting phosphor for G was mixed was coated on the above fluorescent screen, and different exposure light sources g were caused to emit light. The ultraviolet light is expanded by the projection lens, and its light flux is applied to the ultraviolet light transmitting portion provided on the light shielding plate and is transmitted only to the ultraviolet light transmitting portion area, and the visible light emitting phosphor dots r on the fluorescent screen surface are formed. Is projected as a light beam having the same shape as that of the ultraviolet light transmitting portion on a different place. The photosensitive negative resist was exposed only at the place where the ultraviolet light was projected, and the visible light emitting phosphor dots g having the same shape as the ultraviolet light transmitting portion were fixed. After that, the fluorescent screen was washed to remove the visible light emitting phosphor powder G attached to other places.

The same process was carried out on the visible-light-emitting phosphor powder for B to prepare visible-light-emitting phosphor dots b.

Next, a photosensitive positive resist mixed with carbon powder was applied on the fluorescent screen. Driving all exposure light sources, all visible light emitting phosphor dots r,
Ultraviolet rays were irradiated to the positions of g and b. After that, the fluorescent screen was washed to remove the carbon powder covered on each visible light emitting phosphor dot, and the black matrix layer could be formed at a place other than each phosphor dot. The fluorescent screen was completed by the above method.

After the above steps, the resin component remaining in the phosphor dots and the black matrix may be removed by a predetermined method such as a heating method, if necessary.

(Sixth Embodiment) Next, a sixth embodiment of the present invention will be described. FIG. 8 is a cross-sectional view of the fluorescent screen of this example. An ultraviolet cut filter 61 having light resistance is provided on the back side of the screen base 31. As the ultraviolet cut filter material, any suitable inorganic or organic material can be applied. The visible light emitting phosphor dots 62 and the black matrix 33 are provided thereon. Further, a visible light reflection layer 63 is provided on it.

The ultraviolet cut filter 61 is made of a material that transmits the visible light emission 64 of the visible light emitting phosphor dots 62 and absorbs the ultraviolet excitation light 65 from the ultraviolet light source. Further, the visible light reflecting mirror 63 transmits the ultraviolet excitation light 65 on a glass substrate transparent to the ultraviolet excitation light 65, but R,
The visible light emission 64 of G and B was obtained by depositing a predetermined dielectric multilayer film that reflects light.

The following effects can be obtained by this embodiment. That is, since the ultraviolet cut filter blocks the ultraviolet excitation light 65, harmful ultraviolet light does not leak to the front surface of the fluorescent screen. Further, since the visible light reflection layer 63 reflects the visible light emission 64 of the phosphor dots 62 to the front surface, the brightness is improved.

Instead of providing the ultraviolet cut filter 61, the screen substrate 31 itself may be made of a material that does not transmit ultraviolet light. Also, UV cut filter 6
Instead of 1, an ultraviolet light reflecting mirror made of a predetermined dielectric multilayer film that transmits each visible light emission 64 of R, G, B but reflects the ultraviolet excitation light 65 may be used. The ultraviolet light reflecting mirror 63 is
At the same time do not let the ultraviolet light leak to the front of the fluorescent screen,
The ultraviolet light, which is not completely absorbed by the fluorescent layer or the fluorescent dots, is reflected and made incident on the ultraviolet light again, so that the brightness is improved.

[0115]

Industrial Applicability The present invention is directed to an ultraviolet light source that emits ultraviolet light in the form of a plane, a projection lens that is arranged in the passage direction of the ultraviolet light that is emitted from the ultraviolet light source, and the visible light that is irradiated by the ultraviolet light that has passed through the projection lens. Since it is a display device including a phosphor screen having a phosphor layer containing a visible light emitting phosphor that emits light, it is easy to increase the screen size at low cost, and the screen itself emits light, so that the display quality is high. In addition, since a fluorescent screen can be efficiently irradiated with ultraviolet light from a radiation source of ultraviolet excitation light, or the ultraviolet light can be efficiently converted into visible light emission, a large-screen display with high brightness and low power consumption can be realized. . In addition, according to the invention of the present application, it was possible to obtain a fluorescent screen having no color shift with time. Also,
It was possible to easily manufacture a fluorescent screen without color shift. In addition, harmful ultraviolet light does not leak to the outside of the display device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an embodiment of a display device of the present invention.

FIG. 2 is a sectional view of a cathode ray tube used in an embodiment of the display device of the present invention.

FIG. 3 is a perspective view of a fluorescent screen used in an embodiment of the display device of the present invention.

FIG. 4 is a sectional view of a cathode ray tube used in another embodiment of the display device of the present invention.

FIG. 5 is a thin film E used in another embodiment of the display device of the present invention.
Sectional view of L element

FIG. 6 is a cross-sectional view illustrating the configuration of an embodiment of a display device of the present invention.

FIG. 7 is an enlarged view of the vicinity of a light shielding plate and a fluorescent screen used in another embodiment of the display device of the present invention.

FIG. 8 is a sectional view of a fluorescent screen used in another embodiment of the display device of the present invention.

[Explanation of symbols]

 2 Fluorescent Screen 3, 51, 52, 53 Cathode Ray Tube 4 Projection Lens 5, 6 Reflector 11 UV Emitting Phosphor Surface 17 Face Plate 21 UV Emitting Phosphor Layer 22 Multilayer Reflector 23 Metal Reflector 31 Screen Base 32 Visible Fluorescent Body stripe 33 Black matrix 40 Transparent substrate 41 Semiconductor multilayer film reflecting mirror 43 Back reflecting mirror 45 Transparent conductive film 46, 48 Insulating film 47 Ultraviolet light emitting phosphor layer 49 Counter electrode 50 Light shielding plate 54 Ultraviolet light transmitting part 55, 56, 57 , 62 visible light emitting phosphor dots 58, 59, 60 luminous flux 61 ultraviolet cut filter 63 visible light reflecting mirror 64 visible light emission 65 ultraviolet excitation light

Claims (14)

[Claims] 1. An ultraviolet light source that emits ultraviolet light in a planar form, a projection lens that is arranged in the passage direction of the ultraviolet light that is emitted from the ultraviolet light source, and a visible light emission that emits visible light when the ultraviolet light that has passed through the projection lens is irradiated. A display device comprising a phosphor screen having a phosphor layer containing a phosphor. 2. The display device according to claim 1, further comprising a light shielding plate having a portion that transmits ultraviolet light, provided between the projection lens and the fluorescent screen. 3. The display device according to claim 1, wherein an ultraviolet cut filter or an ultraviolet light reflecting mirror is provided on the surface of the phosphor layer of the fluorescent screen opposite to the projection lens side. 4. A visible light reflecting mirror is installed between the fluorescent screen and the projection lens.
The display device according to any one of claims. 5. The display device according to claim 1, wherein the ultraviolet ray source is a cathode ray tube having an ultraviolet light emitting phosphor which emits ultraviolet light when excited by an electron beam, in a planar manner. 6. The display according to claim 5, wherein the cathode ray tube has a planar light emitting layer having an ultraviolet light emitting phosphor and a reflecting mirror disposed on at least one surface of the light emitting layer. apparatus. 7. An ultraviolet light source, wherein the ultraviolet light source includes an ultraviolet light emitting phosphor that emits ultraviolet light by electroluminescence, a dielectric layer provided on at least one surface of the ultraviolet light emitting layer, the ultraviolet light emitting layer and the dielectric layer. 2. The display device according to claim 1, comprising an electrode pair facing each other with a body layer interposed therebetween, and at least one of the electrode pair being a transparent or semitransparent electroluminescent element. 8. The ultraviolet light emitting phosphor is selected from the group consisting of diamond, silicon carbide, III-V group compound semiconductors, IIb-VI group compound semiconductors, IIa-VI group compound semiconductors, chalcopyrite compounds and manganese chalcogenite compounds. It is at least 1 type which is characterized by the above-mentioned.
The display device according to any one of claims. 9. The display device according to claim 8, wherein the ultraviolet light emitting phosphor contains a donor impurity or an acceptor impurity. 10. An ultraviolet light emitting phosphor comprising a phosphate compound, a silicate compound, a yttrium oxide compound, a tungsten oxide compound, an aluminum oxide compound, a rare earth oxide, IIa.
The display device according to claim 5, wherein the display device is at least one selected from the group consisting of —VII ₂ compounds, IIb-VII ₂ compounds, and alkali halides. 11. The ultraviolet-emitting phosphor contains an emission center impurity of either a lanthanoid ion having an f-electron shell or an actinide ion.
Or the display device according to any one of 10. 12. The display device according to claim 11, wherein the emission center impurities are gadolinium ions. 13. An ultraviolet light source that emits ultraviolet light in a planar shape, a projection lens that is arranged in a passage direction of the ultraviolet light that is emitted from the ultraviolet light source, and a visible light emission that emits visible light when the ultraviolet light that has passed through the projection lens is irradiated A display comprising a phosphor screen having a phosphor layer containing a phosphor on the screen, and a light shielding plate having a portion between the projection lens and the phosphor screen, through which the ultraviolet light passing through the projection lens passes. The fluorescent screen of the apparatus, wherein the ultraviolet light emitted from the ultraviolet light source through the projection lens is provided with a pattern exposure light source at a position corresponding to an irradiation area on the fluorescent screen, An exposure step of irradiating and exposing the screen coated with the negative resist containing the visible light emitting phosphor using the shielding plate as a mask, and the negative resist after the exposure step. And a step of developing a pattern of the visible light-emitting phosphor on the screen, and manufacturing the phosphor screen for use in a display device. 14. The method for manufacturing a fluorescent screen used in a display device according to claim 14, wherein the exposure light source is an ultraviolet light source.