JPH012245A - discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a discharge lamp, in particular, to a discharge lamp that does not have an electrode inside the bulb, and uses a high-frequency electromagnetic field from the outside to generate a gas such as a rare gas or metal vapor inside the lamp. This invention relates to technology for preventing luminous flux fading (blackening) in so-called electrodeless discharge lamps, etc.

[Background technology]

So-called electrodeless discharge lamps, which do not have electrodes inside the bulb and discharge gases such as rare gases and metal vapors inside the lamp using a high-frequency electromagnetic field from the outside, have the characteristics of small size, high output, and long life. Because of this, its application as a light source for reading originals in optical devices such as electronic copying machines and facsimile machines is being considered, and research and development are actively being carried out.

Such an electrodeless discharge lamp is usually constructed by filling a bulb with a rare gas and an element desired to emit light.

- Ar is commonly used as the rare gas sealed in the bulb, and mercury (Hg) is used as the element for boat fishing.

Then, a high-frequency magnetic field is applied from outside the bulb to discharge the gases filled in, such as the rare gases and elements, to obtain light.

The distribution of the discharge spectrum of gases is usually biased toward the ultraviolet region, so in discharge lamps for general lighting, a phosphor layer or reflective film is formed on the inner wall of the bulb to The layer works to convert ultraviolet rays into visible light, which is then extracted as light. On the other hand, in the case of lamps in which the discharge itself emits visible light, so-called ultraviolet lamps that extract ultraviolet rays from the discharge, or lamps that emit specific wavelengths, there is no need to provide such a phosphor layer or reflective film. .

In the discharge lamp as described above, the inner wall surface of the bulb becomes black with use, and the luminous efficiency of the lamp decreases, which is a problem called luminous flux attenuation. Luminous flux attenuation is mainly caused by trace amounts of alkali metals (
This occurs when NaSK, Li, etc.) react with elements such as Hg during discharge operation and adhere to the inner wall surface of the bulb.

In normal discharge lamps, in order to prevent such luminous flux attenuation, there is a 1201.5 ins.
Alkali elution prevention treatment is carried out by applying a sol such as Ti1t. However, although such alkali elution prevention 1F treatment is effective (with limitations) for ordinary discharge lamps with built-in electrodes, it is not an effective means for preventing luminous flux decline in the aforementioned electrodeless discharge lamps. This is not possible and has become a problem.

[Object of the invention This invention was made in view of the above circumstances,
The object of the present invention is to provide a discharge lamp having an excellent effect of preventing luminous flux fading.

[Disclosure of the invention]

In order to achieve the above objective, the inventors investigated why the conventional alkali elution prevention treatment does not have sufficient effects.
I considered saying that. As a result, as mentioned above, A1□0
It was found that the film for alkali elution prevention treatment, which is formed by applying a sol such as , 5iO-1TiO-, is not dense and non-uniform, and blackening occurs from thin or weak parts of the film. . Therefore, an attempt was made to form a thick and uniform alkali elution prevention film, and this invention was completed.

That is, the present invention provides a discharge lamp that generates light by discharging gases sealed in the bulb, in which an alkali elution prevention film provided on the inner wall surface of the bulb is formed by coating and baking an organic metal compound solution. The gist is a discharge lamp characterized by:

The present invention will be explained in detail below.

The valves are made of the same materials as before.

That is, if the lamp is a normal fluorescent lamp,
Soda glass, lead glass, etc. are used as bulbs.
When the lamp is an electrodeless discharge lamp, quartz glass or hardened silicate glass (so-called Pyrex glass) is used in order to withstand high temperatures (200 to 300° C.) during operation. Additionally, if the lamp emits light of a specific wavelength, special glass is used accordingly.

The shape of the bulb can also be made into a straight pipe shape, an annular shape, a short arc shape, etc. according to the purpose of use, as in the conventional case.

The alkali elution prevention film formed on the inner wall surface of such a valve is formed by applying and baking a solution of an organic metal compound such as a metal alkoxide.

The structure of the alkali elution prevention film to be formed is not particularly limited in the present invention, but if the lamp is a normal fluorescent lamp or the like, a high refractive index dielectric weight 1 film may be used. Examples of dielectrics with a high refractive index include totally refractive oxides such as Ti1t, Ce(h, and ZrO□), and ZnS. O
t-Cs11t)4, Ti(OCtlls)4, Ce(
tlxcc.

CHOCCH*)s , Ce(llsccOcHOcc
It is formed by applying a coating solution containing an alcohol diluted solution of an organometallic compound such as a metal alkoxide such as H, ) 4 or Zr(Oi-CsHt) 4 and firing.

For applying the coating solution to the inner wall surface of the valve, ordinary coating methods such as dipping coating, in which the bulb is immersed in the coating solution, and a method in which the coating solution is poured into the bulb, are employed.

Components other than the alcohol diluted solution of the organometallic compound contained in the coating solution include (catalyst) IC1;
HNO! , inorganic acids such as o*so4 and cHscoon.

HCOOtl-(CHtCO)2o, Ctl-C
Organic acids such as HzCHtCOOH or N)1. cHO
etc., and water for hydrolysis.

Firing conditions are not particularly limited in the present invention, but heating for 60 minutes or more at a temperature of about 470°C or higher, which is the lower limit temperature at which the organometallic compound described above decomposes (converts into a single layer GT) and becomes the dielectric material described above. However, it is desirable to perform sufficient firing.

This is because, if baking is not carried out sufficiently, carbon in the organic groups may remain in the film, causing the film to turn black, and oxygen in unreacted substances may be absorbed by the manganese ( This is because black MngO* may be produced by reacting with Mn), resulting in a decrease in light transmittance.

The thickness of the resulting high refractive index dielectric thin film is preferably controlled within a range that allows the maximum amount of light at the peak wavelength to be extracted. For example, if the dielectric is Ti1t and the light you want to transmit is visible light, the film thickness is 110
The number should be about 0 to 1200 people.

However, when the wavelengths of the light to be extracted are diverse, for example, when the phosphor layer is composed of several types of phosphors (usually 430 layers m, 540 nm, as shown by the broken line in Figure 2)
(often has peaks at three wavelengths: n+, 610 layer m), etc., it is not possible to control the transmittance of all these wavelengths by simply controlling the thickness of the single layer film, as shown by the solid line in the figure. Therefore, in such a case, 1. As shown in FIG. 1, if the alkali elution prevention film 2 is constituted by an optical multilayer film in which dielectric thin films 2a with a high refractive index and dielectric thin films 2b with a low refractive index are alternately laminated on the inner wall surface of the bulb 1. good.

The dielectric thin film with a high refractive index is the same dielectric as the above single layer film,
formed by a similar method.

As a low refractive index dielectric material that becomes a low refractive index dielectric thin film, SiO^1.0. Metal oxides such as CaF, M
Examples include fluorides such as gFt.

Such a low refractive index dielectric film is 5t (0λ-CsH
v) 4.5i (OCJs) 4, Al (Oz-CJy)
It is formed by applying a coating solution containing an alcohol diluted solution of an organometallic compound such as a metal alkoxide such as s and baking it.

The coating method, firing conditions, components other than the alcohol diluted organic metal compound solution contained in the coating solution, etc. are the same as in the case of the high refractive index dielectric described above.

The number of layers of both dielectric thin films constituting the optical multilayer film is not particularly limited in the present invention, but usually a dielectric thin film 1F with a low refractive index is sandwiched between two dielectric thin films with a high refractive index. 3
The layered structure is sufficient to achieve the purpose. Of course, the optical multilayer film may have two layers, or may have four or more layers. The thickness of each layer is not particularly limited, but in the above three-layer structure, the high refractive index dielectric thin film is TiOx, the low refractive index dielectric thin film is 5iQz, and the light to be transmitted is the entire visible light range, Ti0J. Odor 1100-1200 people, 5iOzl
It is sufficient if there are about 17oo-isoo ffi people.

Such an optical multilayer film can maximize transmittance in the entire visible light region by appropriately selecting the thickness of each dielectric thin film and the refractive index of each layer.

A high refractive index dielectric single layer film formed as described above,
Alternatively, an alkali elution prevention film consisting of an optical multilayer film is
Since it is made by baking an organic metal compound and is a dense and uniform film, it is possible to completely prevent the occurrence of blackening.

If the discharge lamp is one that directly extracts light from gas discharge, the gas for discharge may be sealed in the bulb on which the alkali elution prevention film is formed.

As before, the gases to be sealed include He, Ne,
Rare gases such as ^r-, Kr5XeSRn, and mixtures of these rare gases with elements for emitting light at a specific wavelength are used.

Examples of elements for emitting light at a specific wavelength include, but are not limited to, the following elements.

AS% B15Brs CcL l1g, P % P
b5S SSb,, Se, Sn,, Tes 71
% Zll et al.

Among these elements, those that can be easily vaporized or are gaseous from the beginning may be encapsulated as they are, while elements that are difficult to vaporize may be encapsulated in the form of iodide, chloride, amalgam, etc.

The amount of gases such as rare gases and elements is not particularly limited in the present invention, and the amount of gases may be filled depending on the type of discharge lamp to be formed. For example, when the discharge lamp is an electrodeless discharge lamp, the amount of the element enclosed may be adjusted so that the pressure of the element is optimal at the operating temperature (200 to 300° C.).

If the discharge lamp converts light from gas discharge into visible light and extracts it, after forming a phosphor layer or a reflective film on the alkali elution prevention film,
Gases for the above-mentioned discharge may be sealed in the bulb.

As a phosphor, Cats(PO4)aFcl:Sb:
Mn, 3Cas(PO4)yCaFz:Sb:Mn,
3Cas(POa)tcacIz:Sb:Mn,
ZnxsiOa:Mn, (ZnBe)xsio4:M
An ordinary film consisting of a system such as n, 6Mg0:^5zoa:Mn can be used, and Ties or the like can be used as the reflective film. The phosphor layer and the reflective film can be formed by a conventional method, such as by coating the above-mentioned compounds dispersed in a suitable solvent or the like on the alkali elution prevention film.

Next, examples of the present invention will be described together with comparative examples.

(Example 1) After cleaning a Pyrex glass bulb with a diameter of 16 mm and a length of 300 mm, it was immersed in a T'+Ot coating solution having the following composition, and pulled out of the solution at a pulling speed of 320 mm/min. <riot coating solution formulation> Ti (Qt-CmHt) 4: 1 B g ethanol =
80g Hydrochloric acid: 0.4g Water: 1.6g After removing the coating film formed on the outside of the bulb, 120g
C. for 5 minutes and 600.degree. C. for 60 minutes to form an alkali elution prevention film consisting of a single layer of Ties on the inner wall surface of the bulb. The thickness of the obtained alkali elution prevention film was 1
There were 100-1200 people.

Next, calcium halophosphate (Ca, @(PO4), FCl:Sb:Mn
) After forming a phosphor film, Ar gas and Ilg were sealed to form an electrodeless discharge lamp.

When the resulting electrodeless discharge lamp was lit at high frequency and the transmittance distribution in the visible light region was measured, as shown by the solid line in Figure 2, the emission wavelength of the phosphor was 540 nm.
The light transmittance was 92%. This transmittance was almost the same as that of Pyrex glass on which no alkali elution prevention film was formed, and it was found that the alkali elution prevention film in this example had excellent permeability.

Further, when the luminous efficiency of this electrodeless discharge lamp was measured after being continuously lit for 100 hours, only a decrease of 10% or less was observed.

(Example 2) Instead of the TiO = coating solution, a ZrOx coating solution consisting of the following component composition was used, and this ZrO□
The valve lifting speed from the coating solution was 350n.
An alkali elution prevention film consisting of a single layer of ZrO□ was formed in the same manner as in Example 1, except that the heating time was changed to 1/min, and an electrodeless discharge lamp was produced in the same manner as in Example 1.

Note that the film thickness of Zr0xlW was 1200.

<ZrO□ coating solution formulation> Zr(Of-CsHv) 4: 25 g Butanol: 4
When the transmittance of 540 nm light of the obtained electrodeless discharge lamp was measured, it was found to be almost the same as that of Pyrex glass without an alkali elution prevention film, as in Example 1. It was found that the elution prevention membrane had excellent permeability.

Further, when the luminous efficiency of this electrodeless discharge lamp was measured after being continuously lit for 100 hours, only a decrease of 10% or less was observed.

(Example 3) Instead of the Tilt coating solution, a Cent coating solution consisting of the following ingredient combination was used, and this CeO!
Valve lifting speed from coating solution to 200m
CeO*
An alkali elution prevention film consisting of a single layer film was formed, and the rest was carried out in the same manner as in Example 1 to produce an electrodeless discharge lamp.

The thickness of the CeO film was 1000.

(CeO-coating solution formulation) Ce(H*CC0CHOCCHs): 25 g
Butanol: 30 g When the 540 nm light transmittance of the obtained electrodeless discharge lamp was measured, as in Example 1, it was almost the same as that of Pyrex glass without an alkali elution prevention film. It was found that the alkali elution prevention membrane had excellent permeability.

Further, when the luminous efficiency of this electrodeless discharge lamp was measured after being continuously lit for 100 hours, only a decrease of 10% or less was observed.

(Example 4) After forming a Ti0 = film (high refractive index dielectric thin film) on the inner wall surface of the bulb in the same manner as in Example 1 using the above coating solution, this material was coated with the following components. The sample was immersed in a coating solution of the same composition for 5 inches and pulled out of the solution at a pulling rate of 180 min/min to form a coating film.

(Sins coating solution formulation) 5i (OCJs) a: 22.8 g Ethanolonia 3.6 g Hydrochloric acid: 0.2 g Water: 3.4 g After removing the coating film formed on the outside of the bulb, 120 g
℃ x 5 minutes and 600℃ x 60 minutes, and the above T
5ift film (low refractive index dielectric E4 P!
) were laminated.

Next, a TiO□ film was again placed on this 5ins film under the same conditions as the previous TiO□ film to form an alkali elution prevention film consisting of a three-layered optical multilayer film. The thickness of each layer of the obtained alkali elution prevention film is as follows:
t membrane is 1100-1200 people, 5iO in the middle layer = 1 membrane
There were 700-1800 people.

Next, 3Ca (PO
a) *CaXt:Sb:Mn (wherein X is F or CI
After forming a phosphor film by applying 6Mg0:AsxOs:Mn-added phosphor to
An electrodeless discharge lamp was formed by filling gas and Hg.

When the obtained electrodeless discharge lamp was lit at high frequency and the transmittance distribution in the visible light region was measured, the spectrum curve showed that no alkaline elution prevention film was formed, as seen by the solid line in Figure 3. It almost coincides with that of Pyrex glass (broken line in the figure), and it was found that the alkali elution prevention membrane in this example had excellent permeability.

Further, when the luminous efficiency of this electrodeless discharge lamp was measured after being continuously lit for 100 hours, only a decrease of 10% or less was observed.

On the other hand, an electrodeless discharge lamp prepared in the same manner as in Example 4 except that no alkali elution prevention film was formed had a luminous efficiency of 40% after continuous lighting for 100 hours.
% has also decreased.

(Example 5) Instead of the Si0g coating solution, an AItos coating solution consisting of the following component composition was used, and this AItos coating solution was used.
The valve pulling rate from the os coating solution was set to 25
Ti
An electrodeless discharge lamp was produced in the same manner as in Example 4, except that an alkali elution prevention film having a three-layer structure of O*/AIJ*/TiOx was formed.

Note that the 1lrA thickness of the AlloI layer was 1500.

<Altos coating solution formulation> ^1(OCJ*)s: 22.9 g Butanolnia 3.4 g Hydrochloric acid: 0.4 g Water: 3.3 g Transmittance distribution in the visible light region of the obtained electrodeless discharge lamp As in Example 4, the spectrum curve almost matched that of Pyrex glass without the alkali elution prevention film, indicating that the alkali elution prevention film in this example had excellent permeability. It was found that it has.

Further, when the luminous efficiency of this electrodeless discharge lamp was measured after being continuously lit for 100 hours, only a decrease of 10% or less was observed.

〔Effect of the invention〕

The discharge lamp of the present invention is as described above, and the alkali elution prevention film provided on the inner wall surface of the bulb is a dense and uniform film formed by coating and baking a solution of an organic metal compound such as a metal alkoxide. Therefore, it has an excellent luminous flux reduction prevention effect, and can be effective in preventing luminous flux reduction in, for example, electrodeless discharge lamps.

[Brief explanation of the drawing]

Figure 1 is a layer configuration diagram explaining the state of the bulb and the alkali elution prevention film of a discharge lamp of the present invention in which the alkali elution prevention film is an optical pot rF4, and Figure 2 shows the luminescence distribution of the phosphor and the alkali elution prevention film. Figure 3 is a graph showing an example of the transmittance distribution in the visible light region when the crotch is a single-layer film and when the alkali elution prevention film is an optical multilayer film. This is a graph illustrating an example of the transmittance distribution in the visible light region with a bulb that does not have a light bulb. 1... Valve 2... Alkali elution prevention membrane agent
Patent Attorney Takehiko Matsumoto Figure 2 Figure 3 Wavelength (nm)

Claims (5)

[Claims] (1) In a discharge lamp that generates light by discharging gases sealed in the bulb, the alkali elution prevention film provided on the inner wall of the bulb is formed by coating and baking an organic metal compound solution. A discharge lamp characterized by: (2) The discharge lamp according to claim 1, wherein the alkali elution prevention film is a dielectric single layer film with a high refractive index. (3) The discharge lamp according to claim 1, wherein the alkali elution prevention film is an optical multilayer film in which high refractive index dielectric thin films and low refractive index dielectric thin films are alternately laminated. (4) High refractive index dielectric material is TiO_2, CeO_2, Z
The discharge lamp according to claim 2 or 3, which is at least one selected from the group consisting of rO_2 and ZnS. (5) Low refractive index dielectric material is SiO_2, Al_2O_2
The discharge lamp according to claim 3, wherein the discharge lamp is at least one selected from the group consisting of , CaF_2 and MgF_2.