JPS6228839B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a low-speed electron beam-excited fluorescent display tube whose fluorescent film is a phosphor whose surface is coated with pigment particles (hereinafter referred to as "pigmented phosphor"). As is well known, a low-speed electron beam-excited fluorescent display tube (hereinafter abbreviated as a "fluorescent display tube") has an anode plate having a fluorescent film on one side, and a cathode facing the fluorescent film. The device essentially has a structure in which it is sealed in a vacuum container, and the fluorescent film on the anode plate is excited by the low-speed electron beam emitted from the cathode, causing it to emit light. 1 and 2 are schematic diagrams of typical examples of fluorescent display tubes, with FIG. 1 showing a diode tube and FIG. 2 a triode tube. 1st
As shown in the drawings and FIG. 2, a fluorescent film 12 is provided on one side of an anode plate 11 made of an aluminum plate or the like. Anode plate 11 is supported by ceramic substrate 13. Anode plate 1
A cathode 14 is provided opposite the fluorescent film 12 provided on one side of the fluorescent film 1, and the fluorescent film 12 is excited by the low-speed electron beam emitted from the cathode 14 to emit light. In particular, in the triode shown in Fig. 2, the cathode 14
A grid electrode 15 is provided in the gap between the cathode 14 and the fluorescent film 12 for controlling or diffusing the low-speed electron beam emitted from the cathode 14. Although one cathode 14 is used in the fluorescent display tube shown in FIGS. 1 and 2, two or more cathodes may be provided when the fluorescent film 12 has a large area. There is no particular limit to the number. Fluorescent film 1 on one side
2, a ceramic substrate 13 and a cathode 14 (FIG. 1), or an anode plate 11 having a fluorescent film 12 on one side, a ceramic substrate 13, a cathode 14 and a grid electrode 15 (a second
(Fig.) is sealed in a transparent container 16 made of glass or the like, and the interior 17 thereof is maintained at a high vacuum of 10 ^-5 to ^{10 -9} Torr. Conventionally, zinc-activated zinc oxide phosphor (ZnO:
Zn) is known. When this ZnO:Zn phosphor is excited with a slow electron beam at an accelerating voltage of 1KV or less, particularly 100V or less, it exhibits high-intensity green-white light emission with an emission spectrum peak around 510nm, and this ZnO:Zn A fluorescent display tube having the above structure having a fluorescent film made of a fluorescent substance can be used, for example, in a desktop computer,
It is widely used industrially as a display element for various measuring instruments. Generally, when using a fluorescent display tube with a ZnO:Zn phosphor as a phosphor film as a display element, a part of the visible range of the emission spectrum of the ZnO:Zn phosphor is used to increase the contrast of the display. A filter (a green-white filter) is installed in front of the fluorescent display tube to cut out and absorb some of the external light. However, it is not preferable to install a filter in front of the fluorescent display tube because it increases the number of accessories attached to the fluorescent display tube. In addition, in the case of a fluorescent display tube in which the fluorescent film of each display segment is composed of multiple types of phosphors with different emission colors including ZnO:Zn phosphors, that is, a multicolor fluorescent display tube, the fluorescent film The filter installed on the front of the display tube is effective for increasing the contrast of the light emitted by the segment whose phosphor film is ZnO:Zn phosphor.
This is not preferable because it significantly absorbs light from segments whose fluorescent film is made of a phosphor other than the Zn phosphor.
Therefore, there is a need for a fluorescent display tube that uses a ZnO:Zn phosphor as a fluorescent film and can emit high-contrast light without installing a filter on the front surface. The present invention was made in view of the above-mentioned current situation, and exhibits higher contrast luminescence than a fluorescent display tube using a conventional ZnO:Zn phosphor as a fluorescent film.
Therefore, an object of the present invention is to provide a fluorescent display tube using a ZnO:Zn phosphor as a fluorescent film, which does not require a filter to improve contrast on the front surface when used as a display element. It is something to do. In order to achieve the above object, the present inventors used ZnO:
Various studies have been conducted on improving the contrast of Zn phosphors. As a result, an appropriate amount of TiO ₂ −ZnO
-CoO-NiO based oxide green-white pigment particles are attached to a ZnO:Zn phosphor to make the ZnO:Zn phosphor into a pigmented phosphor. A part of the visible range of the light emission spectrum of the light object is cut out, making the emission color clearer.
Furthermore, they have discovered that contrast is improved because part of the external light is absorbed and reflected light is reduced, leading to the completion of the present invention. That is, the fluorescent display tube of the present invention is a fluorescent display having a structure in which an anode plate having a fluorescent film on one side and a cathode facing the fluorescent film are enclosed in a container with a vacuum inside. In the tube, the fluorescent film is composed of a ZnO:Zn phosphor and TiO ₂ -ZnO-CoO-NiO-based oxide green pigment particles attached to the surface of the phosphor, and the amount of the pigment particles attached is Said
ZnO: It is characterized in that it consists of a pigmented phosphor that is more than 0% by weight and less than 35% by weight of the total amount of the Zn phosphor and the pigment particles. The present invention will be explained in detail below. The ZnO:Zn phosphor used in the pigmented phosphor for fluorescent display tubes of the present invention is produced by baking zinc oxide (ZnO) in a reducing atmosphere or adding a zinc compound such as zinc sulfide (ZnS) to ZnO. It is obtained by a conventionally known manufacturing method such as adding a small amount and firing in air. On the other hand, TiO ₂ −ZnO−CoO−NiO, which is the other component of the pigmented phosphor for fluorescent display tubes of the present invention,
As the green oxide pigment particles, those commonly available on the market are used. TiO ₂ −ZnO−CoO−
NiO-based oxide green pigments are mainly composed of titanium oxide (TiO ₂ ), zinc oxide (ZnO), cobalt oxide (CoO), and nickel oxide (NiO).
TiO ₂ -ZnO-CoO-NiO-based oxide green pigment particles used in the pigmented phosphor of the present invention, although the body color varies depending on the manufacturing method, particle size, content of each of the above components, etc. is the reflectance in the visible range, i.e. 400nm, 450nm, 500nm, 550nm, 600n, when the reflectance of the magnesium oxide diffuser plate is 100%.
The reflectance at m, 650 nm and 700 nm is within the range shown in the table below.

[Table] Figure 3, curve e, illustrates the reflection spectrum of TiO ₂ -ZnO-CoO-NiO based oxide green pigment particles used in the pigmented phosphor for fluorescent display tubes of the present invention. In FIG. 3, the reflectance on the vertical axis is shown as a relative value with the reflectance of the magnesium oxide diffuser plate as 100%. Further, the TiO ₂ -ZnO-CoO-ZiO type oxide green pigment particles used in the pigmented phosphor for a fluorescent display tube of the present invention preferably have an average particle diameter of 3.0 μm or less. Average particle size is larger than 3.0μ
When TiO ₂ -ZnO-CoO-Nio based oxide green pigment particles are used, sufficient adhesion strength cannot be obtained because the particle size is too large. A more preferable average particle diameter is 0.1μ to 1.5μ. ZnO: TiO ₂ −ZnO−CoO−NiO on the Zn phosphor surface
As a method for producing a pigmented phosphor for a fluorescent display tube according to the present invention by depositing green pigment particles, a conventional pigmented phosphor such as that described in JP-A No. 50-56146 can be used. The manufacturing method may also be adopted. In JP-A-50-56146, pigment particles dispersed in a suitable water-soluble resin solution such as polyvinylpyrrolidone and a phosphor dispersed in a gelatin solution are mixed and stirred, and the resulting precipitate is dried. In this way, pigmented phosphors are manufactured. However, in producing a pigmented phosphor, it is important to uniformly and firmly adhere the pigment particles to the surface of the phosphor. Methods for more uniformly and more firmly adhering pigment particles to the surface of the phosphor include a manufacturing method using an electrostatic coating method (Japanese Patent Application Laid-Open No. 133088/1988), which the applicant previously applied for a patent for, and a suspension method. Production method using polymerization method (JP-A-52-133089), copolymerization method (JP-A-53-3980), and production method using a mixture of gelatin and gum arabic as an adhesive (JP-A-53-1989) No. 5088), but a manufacturing method in which a phosphor suspension is mixed with an acrylic or polystyrene emulsion in which pigment particles are dispersed is also recommended. In the pigmented phosphor for fluorescent display tubes of the present invention,
ZnO: TiO ₂ − attached to the surface of Zn phosphor
As the amount of ZnO−CoO−NiO oxide green pigment particles increases, the emission intensity of the pigmented phosphor gradually decreases, but at the same time, the specific reflectance of the pigmented phosphor also gradually decreases. descend. And the contrast of the pigmented phosphor is TiO ₂ -ZnO-CoO-NiO-based oxide.Conventional ZnO without green pigment particles attached:
The contrast is higher than that of Zn phosphor.
TiO ₂ −ZnO−CoO−NiO based oxide The amount of pigmented phosphor that provides the amount of attached green pigment particles (i.e.,
ZnO: more than 0% by weight of the total amount of Zn phosphor and TiO ₂ -ZnO-CoO-NiO-based oxide green pigment particles 35
(hereinafter referred to as TiO ₂ −ZnO−
CoO−NiO oxide green pigment particle adhesion amount by weight%
, the weight percent was calculated in the same way as above). _TiO2 −ZnO−CoO−NiO
When the amount of green pigment particles attached is more than 35% by weight, the contrast of the resulting pigmented phosphor is lower than that of the ZnO:Zn phosphor to which no pigment particles are attached. The purpose is not achieved, and the emission intensity is also significantly reduced. especially
When the amount of TiO ₂ -ZnO-CoO-NiO based oxide green pigment particles is in the range of 5% to 30% by weight, a remarkable contrast effect can be obtained under practical conditions. FIG. 3 shows a pigmented phosphor for a fluorescent display tube of the present invention;
ZnO: This shows the reflection spectra of Zn phosphor and TiO ₂ -ZnO-CoO-NiO-based oxide green pigment particles, and curves a, b and c are TiO ₂ -ZnO-
The curve d of the reflection spectrum of the pigmented phosphor for fluorescent display tubes of the present invention in which the amount of CoO−NiO green oxide pigment particles attached is 0.1, 9, and 33.3% by weight, respectively, is
ZnO: The reflection spectrum of Zn phosphor, curve e is
It is a reflection spectrum of _TiO2 -ZnO-CoO-NiO-based oxide green pigment particles. Note that the reflectance on the vertical axis is shown as a relative value with the reflectance of the magnesium oxide diffuser plate as 100%. As is clear from FIG. 3, the pigmented phosphor used in the fluorescent display tube of the present invention
TiO ₂ −ZnO−CoO−NiO-based oxide green pigment particles are
ZnO has a reflection spectrum peak around 530-550 nm, and this peak exists around 510 nm:
It matches the peak of the emission spectrum of Zn phosphor relatively well. Therefore, TiO ₂ −ZnO attached to the ZnO:Zn phosphor surface has a high reflectance over the entire visible wavelength range (i.e., the body color is white).
−CoO−NiO-based oxide green pigment particles are ZnO:Zn
It selectively transmits the light in the green region emitted by the phosphor, absorbs the light in the visible region other than the green region, and at the same time absorbs the light in the visible region other than the green region of the external light, so that the light on the surface of the phosphor is absorbed. It exhibits an excellent filtering effect in reducing its reflection. _TiO2 −ZnO
As the amount of -CoO-NiO-based oxide green pigment particles attached increases, this filter effect becomes more significant. Figure 4 shows the pigmented phosphor for fluorescent display tubes of the present invention.
It is a graph showing the relationship between the amount of TiO ₂ -ZnO-CoO-NiO-based oxide green pigment particles adhered to the emission intensity (curve a) and the average reflectance (curve b). Emission intensity and average reflectance are both the emission intensity and average reflectance of ZnO:Zn phosphor without pigment particles attached.
The values are shown relative to 100%. Note that the average reflectance is a value expressed as a percentage of the integral value of the reflection spectrum from 400 nm to 700 nm with respect to that of the reflection spectrum of magnesium oxide. Fourth
As is clear from the figure, as the amount of TiO ₂ −ZnO−CoO−NiO-based oxide green particles increases, the average reflectance of the pigmented phosphor gradually decreases, and at the same time, the emission intensity decreases. also gradually decreases. The rate of decrease in average reflectance is greater than the rate of decrease in luminescence intensity until the amount of TiO ₂ −ZnO−CoO−NiO-based oxide green pigment particles adheres to 35% by weight, but at 35% by weight
When exceeding , the rate of decrease in emission intensity is greater than the rate of decrease in average reflectance, and therefore TiO ₂ −ZnO−
When the amount of CoO−NiO-based oxide green pigment particles attached exceeds 35% by weight, the contrast of the resulting pigmented phosphor becomes lower than that of the ZnO:Zn phosphor to which no pigment particles are attached. purpose is not achieved. In other words, the contrast (C) on the phosphor surface of a fluorescent display tube is generally C=B/E ₀ K+1 (where B is the emission intensity of the phosphor surface, E ₀ is the intensity of ambient light, and K is the fluorescence It is expressed as the reflectance of the film surface), so there are no pigment particles attached.
ZnO: When a phosphor surface made of Zn phosphor and a phosphor surface made of pigmented phosphor emit light under ambient light E ₀ , the contrast is C ₀ and C, respectively. If the emission intensity on the film surface is B ₀ and B, and the reflectance on the fluorescent film surface is K ₀ and K, respectively, then the difference between the contrasts C ₀ and C is C ₀ −C=1/E ₀・B ₀ /K ₀ {1-(B/B ₀ )/
(K/K ₀ )}. Therefore, the ratio of the luminescence intensity (B/B ₀ ) and the reflectance of the phosphor film surface made of a pigmented phosphor and the phosphor film surface made of a ZnO:Zn phosphor to which no pigment particles are attached. It can be seen that when the ratio of (K/K ₀ ), that is, the value of (B/B ₀ )/(K/K ₀ ), is 1 or more, C becomes larger than C ₀ regardless of the intensity of the ambient light. . This shows that when comparing a phosphor film surface made of a pigmented phosphor and a phosphor film surface made of a ZnO:Zn phosphor to which no pigment particles are attached, the relative luminescence intensity of the former to that of the latter is shown. When the value (B/B ₀ ) is larger than the relative value (K/K ₀ ) of the average reflectance of the former to the average reflectance of the latter, the former, that is, the surface of the phosphor film made of the pigmented phosphor has more pigment. This means that the contrast is higher than that of a phosphor film surface made of ZnO:Zn phosphor without particles attached. As is clear from Figure 4, when the amount of TiO ₂ -ZnO-CoO-NiO-based oxide green pigment particles attached is 35% by weight or less, the luminance value is larger than the average reflectance value, and A pigmented phosphor in which the amount of TiO ₂ −ZnO−CoO−NiO-based oxide green pigment particles attached is in the range of more than 0% by weight and less than 35% by weight is a ZnO:Zn phosphor without pigment particles attached. Provides a fluorescent film with higher contrast. The ambient light intensity (E ₀ ) is 200 ft-L (indoor brightness during the day is around this level), and ZnO:Zn
At 200ft, the emission intensity (B ₀ ) of the phosphor is close to the emission intensity of ZnO:Zn phosphor in currently practical fluorescent display tubes.
When the contrast of the pigmented phosphor is calculated and illustrated using the above-mentioned formula for a practical ambient light intensity and emission intensity of -L, the results shown in FIG. 5 are obtained. That is, FIG. 5 shows the pigmented phosphor for fluorescent display tubes of the present invention under practical conditions.
It is a graph showing the relationship between the amount of TiO ₂ -ZnO-CoO-NiO-based oxide green pigment particles attached and contrast. Contrast naturally changes as the ambient light intensity and the emission intensity of the ZnO:Zn phosphor change, but the fifth
As is clear from the figure, ambient light intensity and ZnO:
Under practical conditions where the emission intensity of the Zn phosphor is 200 ft-L, the amount of TiO ₂ -ZnO-CoO-NiO oxide green pigment particles attached is in the range of 5% to 30% by weight. In some cases, the contrast of the fluorescent film is significantly improved. The fluorescent display tube of the present invention is manufactured by the method described below. First, the pigmented phosphor described above is coated by a precipitation coating method onto an anode plate, which is usually supported by a ceramic substrate, to form a phosphor film.
That is, an anode plate is placed in a suspension of a pigmented phosphor dispersed in water, and the pigmented phosphor is applied by settling onto one side of the anode plate by the weight of the pigmented phosphor. The water is then removed and the coating is dried. In order to improve the adhesion of the resulting fluorescent film to the anode plate, a small amount (0.01 to 0.1%) of water glass may be added to the suspension. The appropriate coating density is 2 mg/cm ² to 30 mg/cm ² .
Although the above-mentioned precipitation coating method is generally used as a method for forming a fluorescent film and is widely practiced, the method for forming a fluorescent film in the fluorescent display tube of the present invention is not limited to this precipitation coating method. Next, the linear heater is BaO,
A cathode coated with an oxide such as SrO or CaO is placed facing the fluorescent film on the anode plate with an interval of approximately 1 mm to 5 mm, and this pair of electrodes is placed in a transparent container such as glass. After installing the container, exhaust the inside of the container. When the inside of the container reaches a vacuum level of at least 10 ^-5 Torr, stop the exhaust and seal it. After sealing, the getter is removed to further increase the vacuum inside the container. In this manner, the fluorescent display tube of the present invention can be obtained. Note that the fluorescent film on the anode plate is flat,
Since the cathode is linear, it is desirable to install a mesh-like grid electrode as a diffusion electrode between the cathode and the fluorescent film, as shown in FIG. 2, in order to diffuse the low-speed electron beam emitted from the cathode. In this case, better results can be obtained if the mesh is as narrow as possible so that the loss of the amount of light emitted by the fluorescent film is small and the low-speed electron beam is well diffused. Specifically, it is desirable that the diameter of the mesh is 500 microns or less, and the aperture ratio (the area of the holes that transmit low-speed electron beams relative to the total area of the grid electrode) is 50% or more. The anode plate can display any character or figure by dividing its electrode form into the required character or figure shapes and making it possible to selectively apply the required voltage to each electrode. be able to. In addition, the anode plate is divided into dots or lines, and a fluorescent film of the pigmented phosphor of the present invention is formed on some of the electrodes, and the pigmented phosphor emits light on other electrodes. A fluorescent display tube capable of displaying multiple colors can be obtained by forming a fluorescent film made of fluorescent materials for excitation of slow electron beams of different colors. As explained above, the present invention has an acceleration voltage of 1KV.
Hereinafter, we will provide a high-contrast fluorescent display tube whose fluorescent film is a pigmented phosphor that emits light with higher contrast than conventional ZnO:Zn phosphors, especially when excited with a slow electron beam of 100 V or less. It is something to do. When using the fluorescent display tube of the present invention as a display element, it is necessary to add a filter to improve the contrast, as in the case of conventional fluorescent display tubes using ZnO:Zn phosphor as the fluorescent film. There is no need to install it in front of it. Next, the present invention will be explained with reference to Examples. Example 1 50 g of ZnO:Zn phosphor was placed in a 300 ml beaker, 100 ml of pure water was added, and the mixture was stirred for 15 minutes using a magnetic stirrer to prepare a water-dispersed suspension of ZnO:Zn phosphor. TiO ₂ −ZnO−CoO− with an average particle size of approximately 0.5μ is contained in the resulting aqueous suspension of the phosphor.
5 g of NiO-based oxide green pigment particles (Dainichisei Chemical Industry Co., Ltd. #9320) were added and stirred for 30 minutes using a magnetic stirrer to form a uniformly dispersed suspension of the ZnO:Zn phosphor and the pigment particles. Next, 0.17 ml of acrylic emulsion (Nicazole RX-242 manufactured by Nippon Carbide, solid content 60%) was diluted 10 times and added to the uniformly dispersed suspension of phosphor-pigment particles, followed by stirring for 15 minutes. After standing, the supernatant liquid was removed by decantation, and the precipitate was dried at 100°C for 3 hours and passed through a 300 mesh sieve. In this way, a pigmented phosphor for excitation with slow electron beams was obtained with a pigment particle adhesion amount of 9.1% by weight. Next, the pigmented phosphor 100 obtained as described above was
A phosphor film was deposited on a 2 cm x 1 cm aluminum anode plate supported by a ceramic substrate by a precipitation coating method using a suspension of 1.0 mg of water glass dispersed in 100 ml of distilled water containing 0.01% water glass. Formed. Next, a cathode made of a tungsten wire heater coated with oxide is placed facing the fluorescent film on the anode plate with an interval of approximately 5 mm, and this pair of electrodes is placed in a hard glass container. , the inside of the container was evacuated. After the vacuum level inside the container reaches approximately 10 ^-5 Torr, the exhaust is stopped and the container is sealed.
Next, the getter was blown off to further increase the degree of vacuum inside the container. In this manner, a fluorescent display tube having the structure shown in FIG. 1 was produced. When the fluorescent film was excited under the same conditions, the resulting fluorescent display tube was as good as a conventional fluorescent display tube prepared in the same manner as described above using a ZnO:Zn phosphor to which no pigment particles were attached. When the luminous intensity is 200ft-L, 130ft-
The luminescence intensity of L is shown. At this time, the contrast of this fluorescent display tube is approximately 1.3 times that of a conventional fluorescent display tube when the ambient light intensity is 200 ft-L, and even without a filter on the front of the fluorescent display tube, it can be compared to a conventional fluorescent display tube. It showed light emission with good contrast, similar to when a filter was placed in front of the fluorescent display tube. Example 2 ZnO: 49g of Zn phosphor and TiO ₂ -ZnO-
A pigmented phosphor for excitation with a slow electron beam was obtained in the same manner as in Example 1, except that 1 g of CoO--NiO-based oxidized green pigment particles was used, and the amount of pigment particles attached was 2% by weight. Next, using the obtained pigmented phosphor, Example 1
A fluorescent display tube having the structure shown in FIG. 1 was prepared in the same manner as above. When the fluorescent film was excited under the same conditions, the resulting fluorescent display tube was as good as a conventional fluorescent display tube prepared in the same manner as described above using a ZnO:Zn phosphor to which no pigment particles were attached. When the luminous intensity is 200ft-L, 136ft-
The luminescence intensity of L is shown. At this time, the contrast of this fluorescent display tube is approximately 1.05 times that of a conventional fluorescent display tube when the ambient intensity is 200 ft-L, and even if no filter is installed in front of the fluorescent display tube, the contrast of the fluorescent display tube is approximately 1.05 times that of a conventional fluorescent display tube. Light emission with good contrast was exhibited, similar to when a filter was placed in front of the light display tube. Example 3 ZnO: 40g of Zn phosphor, TiO ₂ −ZnO−CoO−
A pigmented phosphor for low-speed electron beam excitation with a pigment particle adhesion amount of 20% by weight was obtained in the same manner as in Example 1, except that 10 g of NiO-based oxide green pigment particles and 0.34 ml of acrylic emulsion were used. . Next, using the obtained pigmented phosphor, Example 1
A fluorescent display tube having the structure shown in FIG. 1 was prepared in the same manner as above. When the fluorescent film was excited under the same conditions, the resulting fluorescent display tube was as good as a conventional fluorescent display tube prepared in the same manner as described above using a ZnO:Zn phosphor to which no pigment particles were attached. When the luminous intensity is 200ft-L, 96ft-L
The luminescence intensity was shown as follows. At this time, the contrast of this fluorescent display tube is approximately 1.26 times that of a conventional fluorescent display tube when the ambient light intensity is 200 ft-L, and even without a filter installed in front of the fluorescent display tube, the contrast of the fluorescent display tube is approximately 1.26 times that of a conventional fluorescent display tube. Light emission with good contrast was exhibited, similar to when a filter was placed in front of the light display tube.

[Brief explanation of the drawing]

1 and 2 are schematic diagrams of typical examples of fluorescent display tubes, with FIG. 1 being a diode and FIG. 2 being a triode. FIG. 3 shows the pigmented phosphor for fluorescent display tubes of the present invention, the ZnO:Zn phosphor, and the TiO ₂ −ZnO−CoO− used in the pigmented phosphor for fluorescent display tubes of the present invention.
It is a graph showing the reflection spectrum of NiO-based oxide green pigment particles. FIG. 4 is a graph showing the relationship between the amount of TiO ₂ --ZnO--CoO--NiO-based oxide green pigment particles adhered to the pigmented phosphor for a fluorescent display tube of the present invention, the emission intensity, and the average reflectance. FIG. 5 shows the pigmented phosphor for fluorescent display tubes of the present invention, TiO ₂ −ZnO−CoO.
- It is a graph showing the relationship between the amount of adhesion of NiO-based oxide green pigment particles and contrast. 11... Anode plate, 12... Fluorescent film, 13
... Ceramic substrate, 14 ... Cathode, 15 ... Grid electrode, 16 ... Container, 17 ... Inside of display tube kept in high vacuum.

Claims (1)

[Scope of Claims] 1. A low-speed electron beam-excited fluorescent lamp having a structure in which an anode plate having a fluorescent film on one side and a cathode facing the fluorescent film are enclosed in a vacuum container. In the light display tube, the phosphor film is attached to a zinc-activated zinc oxide phosphor and to the surface of this phosphor.
TiO ₂ -ZnO-CoO-NiO-based oxide green pigment particles, and the amount of the pigment particles attached is more than 0% by weight and not more than 35% by weight of the total amount of the phosphor and the pigment particles. A low-speed electron beam-excited fluorescent display tube comprising a fluorescent material. 2 The reflectance of the pigment particles is 400 nm, 450 nm,
500nm, 550nm, 600nm, 650nm and 700nm
When the reflectance of the magnesium oxide diffuser plate is 100% at the wavelength of A low-speed electron beam-excited fluorescent display tube according to claim 1, characterized in that: 3 The pigment particle adhesion amount is 5% by weight to 30% by weight.
A low-speed electron beam-excited fluorescent display tube according to claim 1 or 2, characterized in that the fluorescent display tube is within the range of .