EP0389717A2 - Ultraviolet ray-shielding tube - Google Patents
Ultraviolet ray-shielding tube Download PDFInfo
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- EP0389717A2 EP0389717A2 EP89312420A EP89312420A EP0389717A2 EP 0389717 A2 EP0389717 A2 EP 0389717A2 EP 89312420 A EP89312420 A EP 89312420A EP 89312420 A EP89312420 A EP 89312420A EP 0389717 A2 EP0389717 A2 EP 0389717A2
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- European Patent Office
- Prior art keywords
- ultraviolet ray
- shielding
- tube
- binder
- lamps
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J61/00—Gas-discharge or vapour-discharge lamps
- H01J61/02—Details
- H01J61/38—Devices for influencing the colour or wavelength of the light
- H01J61/40—Devices for influencing the colour or wavelength of the light by light filters; by coloured coatings in or on the envelope
Definitions
- the present invention relates to an ultra-violet ray-shielding agent and tube. More particularly, the present invention relates to an ultraviolet ray-shielding agent and tube for a discharge lamp.
- luminescent lamps for example, mercury lamps, metal halide vapor lamps, sodium lamps, xenon lamps and halogen lamps, have an excellent luminance and brightness, a high illumination efficiency, and a long durability, and thus are useful for illuminating buildings such as shops, and as fish-luring lamps.
- Luminescent lamps irradiate strong ultraviolet rays in addition to visible rays, and due to recent increases in the luminance or brightness of the luminescent lamps, for example, halogen lamps, the ultraviolet ray-radiation therefrom can no longer be ignored. Namely, when these lamps are used to illuminate, for example, department stores, the ultraviolet rays cause a discoloration and deterioration of the goods, and when used as fish-luring lights, the ultraviolet rays burn the skin of the users and may cause skin cancer or a deterioration of the eyesight of the users. Therefore, it is necessary that some form of shielding from the ultraviolet rays emitted by luminescent lamp be provided.
- titanium dioxide or cerium oxide is utilized as the ultraviolet ray-shielding material, but these compounds are disadvantageous in that they have the following properties:
- ultraviolet ray-shielding coating materials must satisfy all of the following requirements:
- An object of the present invention is to provide an ultraviolet ray-shielding agent and tube for luminescent lamps, which have a high transparency to and a low scattering of visible rays, and provide an effective shield against ultraviolet rays.
- the above-mentioned object can be attained by the ultraviolet ray-shielding agent and tube of the present invention for luminescent lamps.
- the ultraviolet ray-shielding agent of the present invention comprises; a binder capable of transmitting visible rays therethrough, and extremely fine zinc oxide particles having an average size of 0.1 ⁇ m or less and dispersed in the binder in a mixing ratio of the zinc oxide particles to the binder of 1:10 to 10:1.
- the ultraviolet ray-shielding tube of the present invention for visible ray-irradiation luminescent lamps comprises a transparent substrate tube for sealing a light emission source therein, and at least one ultraviolet ray-shielding coating formed on at least one surface of the substrate tube, comprising a binder capable of transmitting visible rays therethrough and extremely fine zinc oxide particles having an average size of 0.1 ⁇ m or less and dispersed in the binder in a mixing ratio of the zinc oxide particles to the binder of 1:10 to 10:1; this coating having a thickness of 0.5 to 50 ⁇ m.
- the ultraviolet ray-shielding agent and tube of the present invention provide an effective shield against ultraviolet rays without reducing the luminance or brightness and the color-rendering property of the luminescent lamps.
- the ultraviolet ray-shielding agent of the present invention usable for luminescent lamps comprises a binder capable of transmitting visible rays therethrough and extremely fine zinc oxide (ZnO) particles having an average size of 0.1 ⁇ m or less, and dispersed in the binder.
- the mixing ratio of the zinc oxide particles to the binder is from 1:10 to 10:1.
- the upper end wave length in the ultraviolet ray-absorption of zinc oxide is about 380 nm; which is very close to 400 nm, an upper end of the ultraviolet ray band.
- the conventional zinc oxide particle having a size of more than 0.1 ⁇ m exhibit high visible ray-scattering and shielding properties and thus appear white, and therefore, the conventional zinc oxide particles are used as a white pigment. But when used as a coating material for a luminescent lamp, and thus the conventional zinc oxide particles reduce the luminance and color-rendering property of the luminescent lamp, and thus the conventional zinc oxide particles are useless as a visible ray-transmitting coating material.
- the extremely fine zinc oxide particles of the present invention having a size of 0.1 ⁇ m or less have a very sharp end in the ultraviolet ray absorption located at a wave length close to 400 nm and can transmit and scatter the visible rays, and therefore, are very suitable as a coating material capable of transmitting and scattering the visible rays and selectively shielding the ultraviolet rays.
- the extremely fine zinc oxide particles having an average size of 0.1 ⁇ m or less are evenly dispersed, preferably in the binder, in a mixing ratio of the zinc oxide particle to the binder, of 1:10 to 10:1, preferably 2:1 to 1:2.
- the mixing ratio When the mixing ratio is lower than 1/10, the resultant ultraviolet ray-shielding agent exhibits an unsatisfactory ultraviolet ray-shielding effect. Also, a mixing ratio of higher than 10/1 causes the resultant ultraviolet ray-shielding agent layer to exhibit an unsatisfactory mechanical strength.
- the binder usable for the present invention must be capable of forming a solid film having a high transparency for visible rays, a satisfactory heat resistance and durability, provide a satisfactory dispersion of the extremely fine zinc dioxide particles therein, and firmly adhere to a substrate tube or bulb for containing an emission source.
- the binder should have a thermal expansion coefficient similar to that of the substrate tube.
- the binder usable for the present invention preferably comprises at least one member selected from the group-consisting of colloidal silica, polysiloxanes, polyborosiloxanes, polycarbosilanes, and polyphosphazenes.
- the colloidal silica is preferably selected from aqueous silica sol and a hydrolysis product of a silicon alkoxide.
- the polysiloxane can be selected from conventional polysiloxane resins.
- the binder may contain specific metal ions or boron to adjust the thermal expansion coefficient of the resultant ultraviolet ray-shielding coating layer to the same level as that of the substrate tube of the luminescent lamp.
- the ultraviolet ray-shielding tube of the present invention for visible ray-irradiation luminescent lamps comprises a transparent substrate tube for sealing a light emission source therein, and at least one ultraviolet ray-shielding coating layer formed on at least one surface of the substrate tube.
- the coating layer comprises the ultraviolet ray-shielding agent as mentioned above, and has a thickness of 0.5 to 50 ⁇ m, preferably, 3 to 30 ⁇ m.
- the resultant coating layer When the thickness is less than 0.5 ⁇ m, the resultant coating layer exhibits an unsatisfactory ultraviolet ray-shielding effect. Also, when the thickness is more than 50 ⁇ m, the resultant coating layer reduces the luminance and color-rendering property of the tube.
- the transparent substrate tube is usually formed of a glass, for example, a quartz glass.
- the substrate tube to be coated with the ultraviolet ray-shielding agent may be an outer bulb of a luminescent lamp or an inner tube for sealing a light emission source of a luminescent lamp.
- the luminescent lamp is selected from the group consisting of mercury vapor lamps, metal halide vapor lamps, sodium lamps, xenon lamps, and halogen lamps.
- the ultraviolet ray shielding coating layer is formed, in a xenon lamp or halogen lamp, on either one or both of the outside and inside surfaces of the outer bulb, and in a mercury vapor lamp, metal halide vapor lamp or sodium lamp, on either one or both of the outside and inside surfaces of an outer bulb or on the outside surface of an inner bulb.
- a halogen lamp has a outer bulb 1 made from a quartz glass and a light emission source 2 (tungsten filaments), and an ultraviolet ray-shielding coating 3 is formed on an outside surface of the outer bulb 1; i.e., the coating layer 3 is exposed to the ambient air atmosphere.
- a light emission source 2 tungsten filaments
- a mercury vapor lamp has an outer bulb 1, main electrodes 4, supplementary electrodes 4, a light-emission inner tube 6, conductive supporting rods 7, an initiating resistance element 9, and an ultraviolet ray-shielding coating 3 is formed on the outside surface of the outer tube 1; i.e., the coating layer 3 is exposed to the ambient air atmosphere.
- an ultraviolet ray-shielding coating 3 is formed on the outside surface of the light-emission inner tube 6. The coating 3 is exposed to the gas atmosphere contained in the outer bulb 1.
- the ultraviolet ray-shielding coating can be formed by applying a coating liquid containing the ultraviolet ray-shielding agent of the present invention on a surface of an outer or inner bulb of the luminescent lamp, by a dipping method, spraying method, flow coating method, or brushing method, and solidifying the coated liquid by drying.
- a mixture of 100 parts by weight of tetraethoxy silane, 300 parts by weight of isopropyl alcohol, and 35 parts by weight of a 0.1N hydrochloric acid aqueous solution was stirred at a temperature of 60° for 2 hours to prepare an aqueous silica colloid dispersion.
- the resultant aqueous silica colloid dispersion was mixed with 30 parts by weight of zinc oxide particles having a size of from 0.005 ⁇ m to 0.02 ⁇ m and an average size of 0.01 ⁇ m, and the mixture was dispersed in a sand mill for 2 hours to provide a coating liquid.
- This coating liquid contained extremely fine particles of zinc oxide and silica, 99% by weight of which have a size of 0.1 ⁇ m or less.
- a quartz outer bulb for a 100 W halogen luminescent lamp was immersed in the coating liquid and taken up at a constant speed to form a liquid coating having an even thickness on the outside surface of the bulb and the liquid coating was dried at a temperature of 150°C for 15 minutes, to provide a transparent coating having a thickness of 1.5 ⁇ m.
- the resultant conventional halogen luminescent lamp had the relationship between a wave length and a relative intensity of emission of irradiated rays through the non-coated outer bulb, as shown in Fig. 2.
- the rays irradiated through the non-coated outer bulb contain a specific intensity of ultraviolet rays having a wave length of 400 nm or less.
- the conventional lamp exhibited an intensity of illumination and a quantity of ultraviolet ray irradiation as shown in Table 1.
- Figure 3 shows a relationship between a wave length and a relative intensity of emission of rays irradiated from the halogen luminescent lamp through the outer bulb coated with the ultraviolet ray-shielding agent.
- the coating formed on the outer bulb surface shielded only the ultraviolet rays, without shielding the visible rays.
- Example 2 The same coating liquid as mentioned in Example 1 was applied to an outside surface of a quartz outer bulb of a 1000 W mercury vapor luminescent lamp by a flow-coating method and the resultant liquid coating was dried at a temperature of 150°C for 15 minutes.
- the non-coated outer bulb exhibited a spectral transmittance performance as indicated in Fig. 5.
- Figure 5 shows that the non-coated outer bulb allowed the transmission of ultraviolet rays having a wave length of about 400 nm or less therethrough.
- the conventional mercury vapor luminescent lamp having the non-coated outer bulb exhibited the intensity of illumination and quantity of ultraviolet ray irradiation as shown in Table 1.
- the resultant coated outer bulb did not allow a transmission of the ultraviolet rays therethrough, as indicated in Fig. 6. Also, from a comparison of Fig. 6 with Fig. 5, it is clear that the coated outer bulb did not shield the visible rays.
- the mercury vapor luminescent lamp having the coated outer bulb exhibited the intensities of illumination and quantities of ultraviolet ray irradiation at the initial stage of the lighting operation, and at 1000 hours after the start of the lighting operation, as indicated in Table 1.
- a light-emission inner bulb made from a quartz glass was immersed in the same coating liquid as described in Example 1 and taken up at a constant speed and the resultant coating formed on the outer surface of the inner bulb was dried at a temperature of 500°C for 30 minutes. The above-mentioned procedures were repeated twice, and the resultant transparent coating had a thickness of 2.0 ⁇ m.
- the coated inner bulb was inserted into an outer bulb made from a brone-silicic acid glass to provide a 1000 W mercury vapor luminescent lamp as shown in Figs. 7A and 7B.
- the resultant mercury vapor luminescent lamp exhibited a spectral transmittance performance as indicated in Fig. 8.
- Figure 8 clearly shows that the ultraviolet rays having a wave length of about 400 nm or less are shielded by the coated inner bulb.
- the mercury vapor luminescent lamp having the coated inner bulb exhibited the intensities of illumination and quantities of ultraviolet ray irradiation at the initial stage of the lighting operation, and at 1000 hours after the start of the lighting operation, as indicated in Table 1.
- Example 2 The same procedures as those described in Example 1 were carried out except that the titanium oxide particles in the coating liquid had a size of from 0.05 to 0.1 ⁇ m and an average size of 0.08 ⁇ m.
- the properties of the comparative lamp having the non-coated bulb and another comparative lamp having the coated bulb are shown in Table 1.
- Table 1 Example No. Example 1 2 3 Comparative Example 1 Item Type of bulb Property Non-coated Intensity of illumination (lx) 138,000 7,880 7,800 7,800 Quantity of ultraviolet ray irradiation (mW/m2) 1.00 1.02 1.02 1.02 Coated Intensity of illumination (lx) Initial stage 14,490 8,060 8,260 6,700 1000 hr after 14,000 7,900 8,100 6,430 Quantity of ultraviolet ray irradiation (mW/m2) Initial stage 0 0 0 0 1000 hr after 0 0 0 0 Note: The intensity of illumination and quantity of ultraviolet ray irradiation were measured at a point 10 cm from the center of the luminescent lamp in Example 1, and 60 cm from the center of the luminescent lamp in Examples 2 and 3 and Comparative Example 1.
- Table 1 clearly shows that, in each of Examples 1 to 3, the resultant ultraviolet ray shielding layer of the present invention did not reduce the intensity of illumination of the luminescent lamp but caused an increase thereof, and had a high durability over a long period of time.
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- Vessels And Coating Films For Discharge Lamps (AREA)
- Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
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Abstract
Description
- The present invention relates to an ultra-violet ray-shielding agent and tube. More particularly, the present invention relates to an ultraviolet ray-shielding agent and tube for a discharge lamp.
- It is known that various types of luminescent lamps, for example, mercury lamps, metal halide vapor lamps, sodium lamps, xenon lamps and halogen lamps, have an excellent luminance and brightness, a high illumination efficiency, and a long durability, and thus are useful for illuminating buildings such as shops, and as fish-luring lamps.
- Luminescent lamps irradiate strong ultraviolet rays in addition to visible rays, and due to recent increases in the luminance or brightness of the luminescent lamps, for example, halogen lamps, the ultraviolet ray-radiation therefrom can no longer be ignored. Namely, when these lamps are used to illuminate, for example, department stores, the ultraviolet rays cause a discoloration and deterioration of the goods, and when used as fish-luring lights, the ultraviolet rays burn the skin of the users and may cause skin cancer or a deterioration of the eyesight of the users. Therefore, it is necessary that some form of shielding from the ultraviolet rays emitted by luminescent lamp be provided.
- Several attempts have been made to shield the ultraviolet rays, as shown in the following description:
- (1) In a metal vapor luminescent lamp, a coating layer of a titanium dioxide is formed on an outside or inside surface of a tube or bulb in which a luminescent source is contained.
- (2) In a xenon lamp, a tube or bulb for containing a luminescent source is made from a transparent quartz containing 10 to 300 ppm of at least one member selected from titanium dioxide and cerium oxide.
- Nevertheless, in the above-mentioned ultraviolet ray-shielding tubes, titanium dioxide or cerium oxide is utilized as the ultraviolet ray-shielding material, but these compounds are disadvantageous in that they have the following properties:
- (1) A high refractive index and a poor transparency, and thus the luminance of the luminescent lamp is lowered.
- (2) When titanium dioxide is used in the form of fine particles, the particles absorb visible rays, and thus the luminance or brightness and color-rendering property of the lamp are lowered, due to a relatively large size of these particles.
- (3) When an organic titanium compound is employed, it is difficult to form a coating layer having a large thickness, and thus the resultant coating layer exhibits an unsatisfactory ultraviolet ray-shielding property.
- (4) The transparent quartz containing titanium dioxide or cerium oxide is expensive. Also there is an upper limit to the amount of titanium dioxide or cerium oxide that can be added to the quartz, and thus the ultraviolet ray-shielding property of the resultant quartz tube or bulb is still unsatisfactory.
- Generally, ultraviolet ray-shielding coating materials must satisfy all of the following requirements:
- (1) The coating material must be able to shield ultraviolet rays at a wave length of around 400 nm or less.
- (2) The coating material must be stable for practical use over a long period.
- (3) The coating material must be harmless to the human body.
- The conventional ultraviolet ray-shielding agents however, cannot satisfy all of the above-mentioned requirements.
- An object of the present invention is to provide an ultraviolet ray-shielding agent and tube for luminescent lamps, which have a high transparency to and a low scattering of visible rays, and provide an effective shield against ultraviolet rays.
- The above-mentioned object can be attained by the ultraviolet ray-shielding agent and tube of the present invention for luminescent lamps. The ultraviolet ray-shielding agent of the present invention comprises; a binder capable of transmitting visible rays therethrough, and extremely fine zinc oxide particles having an average size of 0.1 µm or less and dispersed in the binder in a mixing ratio of the zinc oxide particles to the binder of 1:10 to 10:1.
- Also, the ultraviolet ray-shielding tube of the present invention for visible ray-irradiation luminescent lamps comprises a transparent substrate tube for sealing a light emission source therein, and at least one ultraviolet ray-shielding coating formed on at least one surface of the substrate tube, comprising a binder capable of transmitting visible rays therethrough and extremely fine zinc oxide particles having an average size of 0.1 µm or less and dispersed in the binder in a mixing ratio of the zinc oxide particles to the binder of 1:10 to 10:1; this coating having a thickness of 0.5 to 50 µm.
- The ultraviolet ray-shielding agent and tube of the present invention provide an effective shield against ultraviolet rays without reducing the luminance or brightness and the color-rendering property of the luminescent lamps.
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- Figure 1A is a cross-sectional view of a halogen luminescent lamp to which ultraviolet ray-shielding tube of the present invention is applied;
- Fig. 1B is a magnified cross-sectional view of a portion B of the ultraviolet ray-shielding tube shown in Fig. 1A;
- Fig. 2 is a graph showing a relationship between a wave length and a relative intensity of light emission of rays irradiated from a halogen luminescent lamp through a conventional outer bulb;
- Fig. 3 is a graph showing a relationship between a wave length and a relative intensity of light emission of the rays irradiated from a halogen luminescent lamp through an ultraviolet ray-shielding tube of the present invention;
- Fig. 4A is a cross-sectional view of a mercury luminescent lamp provided with an ultraviolet ray-shielding outer tube according to the present invention;
- Fig. 4B is a magnified cross-sectional view of a portion B of the ultraviolet ray-shielding tube shown in Fig. 4B;
- Fig. 5 is a graph showing a relationship between a wave length and a relative intensity of light emission of the rays irradiated from a conventional mercury luminescent lamp;
- Fig. 6 is a graph showing a relationship between a wave length and a relative intensity of light emission of the rays irradiated through an ultraviolet ray-shielding tube of the present invention when applied to a mercury luminescent lamp;
- Fig. 7A is a cross-sectional view of another mercury luminescent lamp provided with an ultraviolet ray-shielding inner tube according to the present invention;
- Fig. 7B is a magnified cross-sectional view of a portion B of the ultraviolet ray-shielding inner tube shown in Fig. 7A; and,
- Fig. 8 is a graph showing a relationship between a wave length and a relative intensity of light emission of rays irradiated through an ultraviolet ray-shielding tube of the present invention applied to a mercury luminescent lamp, as shown in Fig. 7A and 7B.
- The ultraviolet ray-shielding agent of the present invention usable for luminescent lamps, comprises a binder capable of transmitting visible rays therethrough and extremely fine zinc oxide (ZnO) particles having an average size of 0.1 µm or less, and dispersed in the binder. The mixing ratio of the zinc oxide particles to the binder is from 1:10 to 10:1.
- The upper end wave length in the ultraviolet ray-absorption of zinc oxide is about 380 nm; which is very close to 400 nm, an upper end of the ultraviolet ray band.
- The conventional zinc oxide particle having a size of more than 0.1 µm exhibit high visible ray-scattering and shielding properties and thus appear white, and therefore, the conventional zinc oxide particles are used as a white pigment. But when used as a coating material for a luminescent lamp, and thus the conventional zinc oxide particles reduce the luminance and color-rendering property of the luminescent lamp, and thus the conventional zinc oxide particles are useless as a visible ray-transmitting coating material.
- The extremely fine zinc oxide particles of the present invention having a size of 0.1 µm or less have a very sharp end in the ultraviolet ray absorption located at a wave length close to 400 nm and can transmit and scatter the visible rays, and therefore, are very suitable as a coating material capable of transmitting and scattering the visible rays and selectively shielding the ultraviolet rays.
- In the ultraviolet ray-shielding agent of the present invention, the extremely fine zinc oxide particles having an average size of 0.1 µm or less are evenly dispersed, preferably in the binder, in a mixing ratio of the zinc oxide particle to the binder, of 1:10 to 10:1, preferably 2:1 to 1:2.
- When the mixing ratio is lower than 1/10, the resultant ultraviolet ray-shielding agent exhibits an unsatisfactory ultraviolet ray-shielding effect. Also, a mixing ratio of higher than 10/1 causes the resultant ultraviolet ray-shielding agent layer to exhibit an unsatisfactory mechanical strength.
- The binder usable for the present invention must be capable of forming a solid film having a high transparency for visible rays, a satisfactory heat resistance and durability, provide a satisfactory dispersion of the extremely fine zinc dioxide particles therein, and firmly adhere to a substrate tube or bulb for containing an emission source.
- Also, the binder should have a thermal expansion coefficient similar to that of the substrate tube.
- The binder usable for the present invention preferably comprises at least one member selected from the group-consisting of colloidal silica, polysiloxanes, polyborosiloxanes, polycarbosilanes, and polyphosphazenes.
- The colloidal silica is preferably selected from aqueous silica sol and a hydrolysis product of a silicon alkoxide. The polysiloxane can be selected from conventional polysiloxane resins.
- The binder may contain specific metal ions or boron to adjust the thermal expansion coefficient of the resultant ultraviolet ray-shielding coating layer to the same level as that of the substrate tube of the luminescent lamp.
- The extremely fine zinc oxide particles can be evenly mixed with and dispersed in the binder, together with a solvent for the binder, by using one or more conventional mixing and dispersing devices, for example, a ball mill, sand mill, atomizer, roll mill, homogenizer, and paint shaker.
- The ultraviolet ray-shielding tube of the present invention for visible ray-irradiation luminescent lamps comprises a transparent substrate tube for sealing a light emission source therein, and at least one ultraviolet ray-shielding coating layer formed on at least one surface of the substrate tube. The coating layer comprises the ultraviolet ray-shielding agent as mentioned above, and has a thickness of 0.5 to 50 µm, preferably, 3 to 30 µm.
- When the thickness is less than 0.5 µm, the resultant coating layer exhibits an unsatisfactory ultraviolet ray-shielding effect. Also, when the thickness is more than 50 µm, the resultant coating layer reduces the luminance and color-rendering property of the tube.
- The transparent substrate tube is usually formed of a glass, for example, a quartz glass.
- The substrate tube to be coated with the ultraviolet ray-shielding agent may be an outer bulb of a luminescent lamp or an inner tube for sealing a light emission source of a luminescent lamp.
- There is no specific restriction on the type of luminescent lamps to which the ultraviolet ray-shielding tube of the present invention can be applied, but usually the luminescent lamp is selected from the group consisting of mercury vapor lamps, metal halide vapor lamps, sodium lamps, xenon lamps, and halogen lamps. For example, the ultraviolet ray shielding coating layer is formed, in a xenon lamp or halogen lamp, on either one or both of the outside and inside surfaces of the outer bulb, and in a mercury vapor lamp, metal halide vapor lamp or sodium lamp, on either one or both of the outside and inside surfaces of an outer bulb or on the outside surface of an inner bulb.
- Referring to Figures 1A and 1B, a halogen lamp has a outer bulb 1 made from a quartz glass and a light emission source 2 (tungsten filaments), and an ultraviolet ray-shielding
coating 3 is formed on an outside surface of the outer bulb 1; i.e., thecoating layer 3 is exposed to the ambient air atmosphere. - Referring to Figs. 4A and 4B, a mercury vapor lamp has an outer bulb 1,
main electrodes 4,supplementary electrodes 4, a light-emissioninner tube 6, conductive supportingrods 7, an initiatingresistance element 9, and an ultraviolet ray-shieldingcoating 3 is formed on the outside surface of the outer tube 1; i.e., thecoating layer 3 is exposed to the ambient air atmosphere. - Referring to Figs. 7A and 7B, an ultraviolet ray-shielding
coating 3 is formed on the outside surface of the light-emissioninner tube 6. Thecoating 3 is exposed to the gas atmosphere contained in the outer bulb 1. - The ultraviolet ray-shielding coating can be formed by applying a coating liquid containing the ultraviolet ray-shielding agent of the present invention on a surface of an outer or inner bulb of the luminescent lamp, by a dipping method, spraying method, flow coating method, or brushing method, and solidifying the coated liquid by drying.
- The present invention will be further explained in the following specific examples, which are representative and do not restrict the scope of the present invention.
- A mixture of 100 parts by weight of tetraethoxy silane, 300 parts by weight of isopropyl alcohol, and 35 parts by weight of a 0.1N hydrochloric acid aqueous solution was stirred at a temperature of 60° for 2 hours to prepare an aqueous silica colloid dispersion. The resultant aqueous silica colloid dispersion was mixed with 30 parts by weight of zinc oxide particles having a size of from 0.005 µm to 0.02 µm and an average size of 0.01 µm, and the mixture was dispersed in a sand mill for 2 hours to provide a coating liquid. This coating liquid contained extremely fine particles of zinc oxide and silica, 99% by weight of which have a size of 0.1 µm or less.
- A quartz outer bulb for a 100 W halogen luminescent lamp was immersed in the coating liquid and taken up at a constant speed to form a liquid coating having an even thickness on the outside surface of the bulb and the liquid coating was dried at a temperature of 150°C for 15 minutes, to provide a transparent coating having a thickness of 1.5 µm.
- When a non-coated outer bulb was used, the resultant conventional halogen luminescent lamp had the relationship between a wave length and a relative intensity of emission of irradiated rays through the non-coated outer bulb, as shown in Fig. 2. In Fig. 2, the rays irradiated through the non-coated outer bulb contain a specific intensity of ultraviolet rays having a wave length of 400 nm or less. The conventional lamp exhibited an intensity of illumination and a quantity of ultraviolet ray irradiation as shown in Table 1.
- Figure 3 shows a relationship between a wave length and a relative intensity of emission of rays irradiated from the halogen luminescent lamp through the outer bulb coated with the ultraviolet ray-shielding agent. In a comparison of Fig. 3 with Fig. 2, it is clear that the coating formed on the outer bulb surface shielded only the ultraviolet rays, without shielding the visible rays.
- The halogen luminescent lamp having the coated outer bulb exhibited the intensities of illumination and quantities of ultraviolet ray irradiation at the initial stage of the lighting operation and at 1000 hours after the start of the lighting operation, as indicated in Table 1.
- The same coating liquid as mentioned in Example 1 was applied to an outside surface of a quartz outer bulb of a 1000 W mercury vapor luminescent lamp by a flow-coating method and the resultant liquid coating was dried at a temperature of 150°C for 15 minutes.
- The above-mentioned procedures were repeated twice to provide a transparent coating having a thickness of 2.5 µm.
- Before the application of the coating liquid, the non-coated outer bulb exhibited a spectral transmittance performance as indicated in Fig. 5. Figure 5 shows that the non-coated outer bulb allowed the transmission of ultraviolet rays having a wave length of about 400 nm or less therethrough.
- The conventional mercury vapor luminescent lamp having the non-coated outer bulb exhibited the intensity of illumination and quantity of ultraviolet ray irradiation as shown in Table 1.
- After coating with the coating liquid containing the ultraviolet ray-shielding agent of the present invention, the resultant coated outer bulb did not allow a transmission of the ultraviolet rays therethrough, as indicated in Fig. 6. Also, from a comparison of Fig. 6 with Fig. 5, it is clear that the coated outer bulb did not shield the visible rays.
- The mercury vapor luminescent lamp having the coated outer bulb exhibited the intensities of illumination and quantities of ultraviolet ray irradiation at the initial stage of the lighting operation, and at 1000 hours after the start of the lighting operation, as indicated in Table 1.
- A light-emission inner bulb made from a quartz glass was immersed in the same coating liquid as described in Example 1 and taken up at a constant speed and the resultant coating formed on the outer surface of the inner bulb was dried at a temperature of 500°C for 30 minutes. The above-mentioned procedures were repeated twice, and the resultant transparent coating had a thickness of 2.0 µm.
- The coated inner bulb was inserted into an outer bulb made from a brone-silicic acid glass to provide a 1000 W mercury vapor luminescent lamp as shown in Figs. 7A and 7B.
- The resultant mercury vapor luminescent lamp exhibited a spectral transmittance performance as indicated in Fig. 8. Figure 8 clearly shows that the ultraviolet rays having a wave length of about 400 nm or less are shielded by the coated inner bulb.
- A comparative conventional mercury vapor luminescent lamp having a non-coated inner bulb exhibited intensity of illumination and quantity of ultraviolet ray irradiation as shown in Table 1.
- Also, the mercury vapor luminescent lamp having the coated inner bulb exhibited the intensities of illumination and quantities of ultraviolet ray irradiation at the initial stage of the lighting operation, and at 1000 hours after the start of the lighting operation, as indicated in Table 1.
- The same procedures as those described in Example 1 were carried out except that the titanium oxide particles in the coating liquid had a size of from 0.05 to 0.1 µm and an average size of 0.08 µm.
- The properties of the comparative lamp having the non-coated bulb and another comparative lamp having the coated bulb are shown in Table 1.
Table 1 Example No. Example 1 2 3 Comparative Example 1 Item Type of bulb Property Non-coated Intensity of illumination (lx) 138,000 7,880 7,800 7,800 Quantity of ultraviolet ray irradiation (mW/m²) 1.00 1.02 1.02 1.02 Coated Intensity of illumination (lx) Initial stage 14,490 8,060 8,260 6,700 1000 hr after 14,000 7,900 8,100 6,430 Quantity of ultraviolet ray irradiation (mW/m²) Initial stage 0 0 0 0 1000 hr after 0 0 0 0 Note: The intensity of illumination and quantity of ultraviolet ray irradiation were measured at a point 10 cm from the center of the luminescent lamp in Example 1, and 60 cm from the center of the luminescent lamp in Examples 2 and 3 and Comparative Example 1. - Table 1 clearly shows that, in each of Examples 1 to 3, the resultant ultraviolet ray shielding layer of the present invention did not reduce the intensity of illumination of the luminescent lamp but caused an increase thereof, and had a high durability over a long period of time.
- In Comparative example 1, however, the zinc oxide particles having an average size of more than 0.1 µm caused the resultant luminescent lamp to exhibit a reduced intensity of illumination.
Claims (8)
a binder capable of transmitting visible rays therethrough; and
extremely fine zinc oxide particles having an average size of 0.1 µm or less and dispersed in the binder in a mixing ratio of the zinc oxide particles to the binder of 1:10 to 10:1.
a transparent substrate tube for sealing a light emission source therein, and
at least one ultraviolet ray-shielding coating formed on at least one surface of the substrate tube, comprising a binder capable of transmitting visible rays therethrough and extremely fine zinc oxide particles having an average size of 0.1 µm or less and dispersed in the binder in a mixing ratio of the zinc oxide particles to the binder of 1:10 to 10:1, said coating having a thickness of 0.5 to 50 µm.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP73874/89 | 1989-03-28 | ||
JP7387489A JPH02253554A (en) | 1989-03-28 | 1989-03-28 | Ultraviolet-ray shielding lamp and its manufacture |
Publications (3)
Publication Number | Publication Date |
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EP0389717A2 true EP0389717A2 (en) | 1990-10-03 |
EP0389717A3 EP0389717A3 (en) | 1991-04-24 |
EP0389717B1 EP0389717B1 (en) | 1996-09-11 |
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Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP89312420A Expired - Lifetime EP0389717B1 (en) | 1989-03-28 | 1989-11-29 | Ultraviolet ray-shielding tube |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0389717B1 (en) |
JP (1) | JPH02253554A (en) |
DE (1) | DE68927166T2 (en) |
HK (1) | HK1000298A1 (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4137819A1 (en) * | 1991-11-16 | 1993-05-19 | Wegmann & Co Gmbh | Data carrier e.g. ROM or RAM memory for identifying munitions - contains manually and=or automatically written and read data carriers at defined positions on munitions |
NL9301024A (en) * | 1992-07-08 | 1994-02-01 | Koito Mfg Co Ltd | ELECTRICAL DISCHARGE LAMP DEVICE AS LIGHT SOURCE FOR A CAR LIGHTING DEVICE. |
EP0662704A1 (en) * | 1993-12-28 | 1995-07-12 | Toshiba Lighting & Technology Corporation | Lamp and lighting apparatus utilizing same |
US5464462A (en) * | 1992-09-15 | 1995-11-07 | Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh | Method of making a quartz glass tube having a reduced ultraviolet radiation transmissivity |
DE4432770A1 (en) * | 1994-09-14 | 1996-03-28 | Brueck Alexandra | UV tube |
EP0758141A2 (en) * | 1995-08-05 | 1997-02-12 | Central Research Laboratories Limited | A radio frequency interference shield |
WO1999023687A1 (en) * | 1997-10-31 | 1999-05-14 | Nanogram Corporation | Articles or compositions comprising nanoscale particles; methods of utilizing or producing such particles |
CN110349833A (en) * | 2019-06-02 | 2019-10-18 | 威海鑫润德贸易有限公司 | A kind of fluorescent tube inner coating and preparation method thereof |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4177720B2 (en) * | 2003-06-25 | 2008-11-05 | ハリソン東芝ライティング株式会社 | Flash discharge lamp, flash discharge lamp lighting device and light irradiation device |
JP2006216360A (en) * | 2005-02-03 | 2006-08-17 | Matsushita Electric Ind Co Ltd | Flash discharge tube and stroboscopic device |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2774903A (en) * | 1951-01-17 | 1956-12-18 | Sylvania Electric Prod | Non-actinic fluorescent lamp |
GB937448A (en) * | 1960-09-13 | 1963-09-18 | Philips Electrical Ind Ltd | Improvements in or relating to ultra-violet radiators and envelopes therefor |
DE1915510A1 (en) * | 1967-07-31 | 1970-09-17 | Westinghouse Electric Corp | Lamp bulbs of photo-resistant sodium-cal- - cium silicate glass |
GB2184356A (en) * | 1985-12-18 | 1987-06-24 | Kao Corp | Anti-suntan cosmetic composition |
US4792716A (en) * | 1981-10-29 | 1988-12-20 | Duro-Test Corporation | Energy-efficient electric discharge lamp with reflective coating |
EP0383634A2 (en) * | 1989-02-17 | 1990-08-22 | Kabushiki Kaisha Toshiba | Ultraviolet-suppressed light source, coating agent used in the same, and method for manufacturing the same |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4006378A (en) * | 1975-10-01 | 1977-02-01 | General Electric Company | Optical coating with selectable transmittance characteristics and method of making the same |
NL7805804A (en) * | 1978-05-29 | 1979-12-03 | Philips Nv | DEVICE FOR APPLYING A CONTROL VOLTAGE OVER A PIEEZO ELECTRICAL POSITIONING ELEMENT. |
JPS62131463A (en) * | 1985-11-30 | 1987-06-13 | Iwasaki Electric Co Ltd | High-pressure discharge lamp |
-
1989
- 1989-03-28 JP JP7387489A patent/JPH02253554A/en active Pending
- 1989-11-29 DE DE1989627166 patent/DE68927166T2/en not_active Expired - Fee Related
- 1989-11-29 EP EP89312420A patent/EP0389717B1/en not_active Expired - Lifetime
-
1997
- 1997-09-26 HK HK97101855A patent/HK1000298A1/en not_active IP Right Cessation
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2774903A (en) * | 1951-01-17 | 1956-12-18 | Sylvania Electric Prod | Non-actinic fluorescent lamp |
GB937448A (en) * | 1960-09-13 | 1963-09-18 | Philips Electrical Ind Ltd | Improvements in or relating to ultra-violet radiators and envelopes therefor |
DE1915510A1 (en) * | 1967-07-31 | 1970-09-17 | Westinghouse Electric Corp | Lamp bulbs of photo-resistant sodium-cal- - cium silicate glass |
US4792716A (en) * | 1981-10-29 | 1988-12-20 | Duro-Test Corporation | Energy-efficient electric discharge lamp with reflective coating |
GB2184356A (en) * | 1985-12-18 | 1987-06-24 | Kao Corp | Anti-suntan cosmetic composition |
EP0383634A2 (en) * | 1989-02-17 | 1990-08-22 | Kabushiki Kaisha Toshiba | Ultraviolet-suppressed light source, coating agent used in the same, and method for manufacturing the same |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4137819A1 (en) * | 1991-11-16 | 1993-05-19 | Wegmann & Co Gmbh | Data carrier e.g. ROM or RAM memory for identifying munitions - contains manually and=or automatically written and read data carriers at defined positions on munitions |
NL9301024A (en) * | 1992-07-08 | 1994-02-01 | Koito Mfg Co Ltd | ELECTRICAL DISCHARGE LAMP DEVICE AS LIGHT SOURCE FOR A CAR LIGHTING DEVICE. |
US5464462A (en) * | 1992-09-15 | 1995-11-07 | Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh | Method of making a quartz glass tube having a reduced ultraviolet radiation transmissivity |
US5572091A (en) * | 1992-09-15 | 1996-11-05 | Patent-Treuhand-Gesellschaft f ur elektrische Gl uhlampen mbH | Quartz glass with reduced ultraviolet radiation transmissivity, and electrical discharge lamp using such glass |
EP0662704A1 (en) * | 1993-12-28 | 1995-07-12 | Toshiba Lighting & Technology Corporation | Lamp and lighting apparatus utilizing same |
DE4432770A1 (en) * | 1994-09-14 | 1996-03-28 | Brueck Alexandra | UV tube |
DE4432770C2 (en) * | 1994-09-14 | 1998-11-19 | Brueck Alexandra | UV tube and its use |
EP0758141A2 (en) * | 1995-08-05 | 1997-02-12 | Central Research Laboratories Limited | A radio frequency interference shield |
EP0758141A3 (en) * | 1995-08-05 | 1997-03-12 | Central Research Laboratories Limited | A radio frequency interference shield |
WO1999023687A1 (en) * | 1997-10-31 | 1999-05-14 | Nanogram Corporation | Articles or compositions comprising nanoscale particles; methods of utilizing or producing such particles |
CN110349833A (en) * | 2019-06-02 | 2019-10-18 | 威海鑫润德贸易有限公司 | A kind of fluorescent tube inner coating and preparation method thereof |
Also Published As
Publication number | Publication date |
---|---|
EP0389717A3 (en) | 1991-04-24 |
DE68927166D1 (en) | 1996-10-17 |
JPH02253554A (en) | 1990-10-12 |
EP0389717B1 (en) | 1996-09-11 |
DE68927166T2 (en) | 1997-02-20 |
HK1000298A1 (en) | 1998-02-20 |
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